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K5NEsVinTqpXqDTD | ENG 236: Introduction to the Short Story | 52 Meet the President
Zadie Smith (2016)
“What you got there, then?”
The boy didn’t hear the question. He stood at the end of a ruined pier, believing himself quite alone. But now he registered the presence at his back, and turned.
“What you got there?”
A very old person, a woman, stood before him, gripping the narrow shoulder of a girl child. Both of them local, typically stunted, dim: they stared up at him stupidly. The boy turned again to the sea. All week long he had been hoping for a clear day to try out the new technology–not new to the world, but new to the boy–and now at last here was a break in the rain. Gray sky met gray sea. Not ideal, but sufficient. Ideally he would be standing on a cairn in Scotland or some other tropical spot, experiencing backlit clarity. Ideally he would be–
“Is it one of them what you see through?”
A hand, lousy with blue veins, reached out for the light encircling the boy’s head, as if it were a substantial thing, to be grasped like the handle of a mug.
“Ooh, look at the green, Aggie. That shows you it’s on.”
The boy was ready to play. He touched the node on his finger to the node at his temple, raising the volume. “Are you somebody, then?”
Hair as white as paper. A long, shapeless black dress, made of some kind of cloth, and what appeared to be a pair of actual glasses. Forty-nine years old, type O, a likelihood of ovarian cancer, some ancient debt infraction–nothing more. A blank, more or less. Same went for the girl: never left the country, eighty-five-per-cent chance of macular degeneration, an uncle on the database, long ago located, eliminated. She would be nine in two days. Melinda Durham and Agatha Hanwell. They shared no more DNA than strangers.
“Can you see us?” The old woman let go of her charge and waved her hands wildly. The tips of her fingers barely reached the top of the boy’s head. “Are we in it? What are we?”
The boy, unused to proximity, took a single step forward. Farther he could not go. Beyond was the ocean; above, a mess of weather, clouds closing in on blue wherever blue tried to assert itself. On his first day here the boy had trailed his father on an inspection tour to meet those hands: intent young men at their monitors, over whose shoulders the boy’s father leaned, as he sometimes leaned over the boy to insure he ate breakfast.
“What d’you call one of them there?”
The boy tucked his shirt in all round: “AG 12.”
The old woman snorted as a mark of satisfaction, but did not leave.
He tried looking the females directly in their dull brown eyes. It was what his mother would have done, a kindly woman with a great mass of waist-length flame-colored hair, famed for her patience with locals. But his mother was long dead, he had never known her, he was losing what little light the day afforded. He blinked twice, said, “Hand to hand.” Then, having a change of heart: “Weaponry.” He looked down at his torso, to which he now attached a quantity of guns.
“You carry on, lad,” the old woman said. “We won’t get in your way. He can see it all, duck,” she told the girl, who paid her no mind. “Got something in his hands–or thinks he does.”
She took a packet of tobacco from a deep pocket in the front of her garment and began to roll a cigarette, using the girl as a shield from the wind.
“Them clouds, dark as bulls. Racing, racing. They always win.” To illustrate, she tried turning Aggie’s eyes to the sky, lifting the child’s chin with a finger, but the girl would only gawk stubbornly at the woman’s elbow. “They’ll dump on us before we even get there. If you didn’t have to, I wouldn’t go, Aggie, no chance, not in this. It’s for you I do it. I’ve been wet and wet and wet. And I bet he’s looking at blazing suns and people in their what-have-yous and all-togethers! Int yer? Course you are! And who’d blame you?” She laughed so loud the boy heard her. And then the child–who did not laugh, whose pale face, with its triangle chin and enormous, fair-lashed eyes, seemed capable only of astonishment–pulled at his actual leg, forcing him to mute for a moment and listen to her question.
“Well, I’m Bill Peek,” he replied, and felt very silly, like somebody in an old movie.
“Bill Peek!” the old woman cried. “Oh, but we’ve had Peeks in Anglia a long time. You’ll find a Peek or two or three down in Sutton Hoo. Bill Peek! You from round here, Bill Peek?”
His grandparents? Very possibly. Local and English–or his great-grandparents. His hair and eyes and skin and name suggested it. But it was not a topic likely to engage his father, and the boy himself had never felt any need or desire to pursue it. He was simply global, accompanying his father on his inspections, though usually to livelier spots than this. What a sodden dump it was! Just as everyone had warned him it would be. The only people left in England
were the ones who couldn’t leave.
“From round here, are you? Or maybe a Norfolk one? He looks like a Norfolk one, Aggs, wouldn’t you say?”
Bill Peek raised his eyes to the encampment on the hill, pretending to follow with great interest those dozen circling, diving craft, as if he, uniquely, as the child of personnel, had nothing to fear from them. But the woman was occupied with her fag and the girl only sang “Bill Peek, Bill Peek, Bill Peek” to herself, and smiled sadly at her own turned-in feet. They were too local even to understand the implied threat. He jumped off the pier onto the deserted beach. It was low tide–it seemed you could walk to Holland. He focussed upon the thousands of tiny spirals on the sand, like miniature turds stretching out to the horizon.
Felixstowe, England. A Norman village; later, briefly, a resort, made popular by the German royal family; much fishing, once upon a time. A hundred years earlier, almost to the very month, a quaint flood had killed only forty-eight people. Over the years, the place had been serially flooded, mostly abandoned. Now the sad little town had retreated three miles inland and up a hill. Pop.: 850. The boy blinked twice more; he did not care much for history. He narrowed his attention to a single turd. Arenicola marina. Sandworms. Lugworms. These were its coiled castings. Castings? But here he found his interest fading once again. He touched his temple and said, “Blood Head 4.” Then: “Washington.” It was his first time at this level. Another world began to construct itself around Bill Peek, a shining city on a hill.
“Poor little thing,” Melinda Durham said. She sat on the pier, legs dangling, and pulled the girl into her lap. “Demented with grief she is. We’re going to a laying out. Aggie’s sister is laid out today. Her last and only relation. Course, the cold truth is, Aggie’s sister weren’t much better than trash, and a laying out’s a sight too good for her– she’d be better off laid out on this beach here and left for the gulls. But I ain’t going for her. I do it for Aggie. Aggie knows why. Aggie’s been a great help to me what with one thing and another.”
While he waited, as incidental music played, the boy idly checked a message from his father: at what time could he be expected back at the encampment? At what time could he be expected. This was a pleasing development, being an inquiry rather than an order. He would be fifteen in May, almost a man! A man who could let another man know when he could be expected, and let him know in his own sweet time, when he had the inclination.
“Maud, that was her name. And she was born under the same steeple she’ll be buried under. Twelve years old. But so whorish–” Melinda covered Aggie’s ears, and the girl leaned into the gesture, having mistaken it for affection. “So whorish she looked like a crone. If you lived round here, Bill Peek, you’d’ve known Maud, if you understand me correctly. You would’ve known Maud right up to the Biblical and beyond. Terrible. But Aggie’s cut from quite different sod, thank goodness!” Aggie was released and patted on the head.
The boy placed a number of grenades about his person. In each chapter of the Pathways Global Institute (in Paris, New York, Shanghai, Nairobi, Jerusalem, Tokyo), the boy had enjoyed debating with friends the question of whether it was better to augment around the “facts on the ground,” incorporating whatever was at hand (“flagging,” it was called, the pleasure being the unpredictability), or to choose spots where there were barely any facts to work around. The boy was of the latter sensibility. He wanted to augment in clean, blank places, where he was free to fully extend, unhindered. He looked down the beach as the oil streaks in the sand were overlaid now with a gleaming pavement, lined on either side by the National Guard, saluting him. It was three miles to the White House. He picked out a large pair of breasts to wear, for reasons of his own, and a long, scaled tail, for purposes of strangulation.
I can’t go to no laying out without it. It’s more than my soul’s worth. Oh, Aggie, how did you ever let me leave without it? She’s a good girl, but she’s thoughtless sometimes–her sister were thoughtless, too. Bill Peek, you will keep an eye on her, won’t you? I won’t be a moment. We’re shacked up just on that hill by the old Martello tower. Eight minutes I’ll be. No more. Would you do that for me, Bill Peek?”
Bill Peek nodded his head, once rightward, twice leftward. Knives shot out of his wrists and splayed beautifully like the fronds of a fern.
It was perhaps twenty minutes later, as he approached the pile of rubble–pounded by enemy craft–that had once been the Monument, that young Bill Peek felt again a presence at his back and turned and found Aggie Hanwell with her fist in her mouth, tears streaming, jaw working up and down in an agonized fashion. He couldn’t hear her over the explosions. Reluctantly, he paused. “She ain’t come back.”
“Excuse me?”
“She went but she ain’t come back!”
“Who?” he asked, but then scrolled back until he found it. “M. Durham?” The girl gave him that same astonished look.
“My Melly,” she said. “She promised to take me but she went and she ain’t come back!”
The boy swiftly located M. Durham–as much an expedience as an act of charity–and experienced the novelty of sharing the information with the girl, in the only way she appeared able to receive it. “She’s two miles away,” he said, with his own mouth. “Heading north.”
Aggie Hanwell sat down on her bum in the wet sand. She rolled something in her hand. The boy looked at it and learned that it was a periwinkle–a snail of the sea! He recoiled, disliking those things which crawled and slithered upon the earth. But this one proved broken, with only a pearlescent nothing inside it.
“So it was all a lie,” Aggie said, throwing her head back dramatically to consider the sky. “Plus one of them’s got my number. I’ve done nothing wrong but still Melly’s gone and left me and one of them thing’s been following me, since the pier–even before that.”
“If you’ve done nothing wrong,” Bill Peek said, solemnly parroting his father, “you’ve nothing to worry about. It’s a precise business.” He had been raised to despair of the type of people who spread misinformation about the Program. Yet along with his new maturity had come fresh insight into the complexities of his father’s world. For didn’t those with bad intent on occasion happen to stand beside the good, the innocent, or the underaged? And in those circumstances could precision be entirely guaranteed? “Anyway, they don’t track children. Don’t you understand anything?”
Hearing this, the girl laughed–a bitter and cynical cackle, at odds with her pale little face–and Bill Peek made the mistake of being, for a moment, rather impressed. But she was only imitating her elders, as he was imitating his.
“Go home,” he said.
Instead she set about burrowing her feet into the wet sand.
“Everyone’s got a good angel and a bad angel,” she explained. “And if it’s a bad angel that picks you out”–she pointed to a craft swooping low–“there’s no escaping it. You’re done for.”
He listened in wonderment. Of course he’d always known there were people who thought in this way–there was a module you did on them in sixth grade–but he had never met anyone who really harbored what his anthro-soc teacher, Mr. Lin, called “animist beliefs.”
The girl sighed, scooped up more handfuls of sand, and added them to the two mounds she had made on top of her feet, patting them down, encasing herself up to the ankles. Meanwhile all around her Bill Peek’s scene of fabulous chaos was frozen–a Minotaur sat in the lap of stony Abe Lincoln and a dozen carefully planted I.E.D.s awaited detonation. He was impatient to return.
“Must advance,” he said, pointing down the long stretch of beach, but she held up her hands, she wanted pulling up. He pulled. Standing, she clung to him, hugging his knees. He felt her face damp against his leg.
“Oh, it’s awful bad luck to miss a laying out! Melly’s the one knew where to go. She’s got the whole town up here,” she said, tapping her temple, making the boy smile. “Memoried. No one knows town like Melly. She’ll say, ‘This used to be here, but they knocked it down,’ or, ‘There was a pub here with a mark on the wall where the water rose.’ She’s memoried every corner. She’s my friend.”
“Some friend!” the boy remarked. He succeeded in unpeeling the girl from his body, and strode on down the beach, firefighting a gang of Russian commandoes as they parachuted into view. Alongside him a scurrying shape ran; sometimes a dog, sometimes a droid, sometimes a huddle of rats. Her voice rose out of it.
“Can I see?”
Bill Peek disembowelled a fawn to his left. “Do you have an Augmentor?” “No.”
“Do you have a complementary system?” “No.”
He knew he was being cruel–but she was ruining his concentration. He stopped running and split the visuals, the better to stare her down.
“Any system?” “No.”
“Therefore no. No, you can’t.”
Her nose was pink, a drop of moisture hung from it. She had an innocence that practically begged to be corrupted. Bill Peek could think of more than a few Pathways boys of his acquaintance who wouldn’t hesitate to take her under the next boardwalk and put a finger inside her. And the rest. As the son of personnel, however, Bill Peek was held to a different standard.
“Jimmy Kane had one–he was a fella of Maud’s, her main fella. He flew in and then he flew out–you never knew when he’d be flying in again. He was a captain in the Army. He had an old one of them . . . but said it still worked. He said it made her nicer to look at when they were doing it. He was from nowhere, too.”
“Nowhere?” “Like you.”
Not for the first time the boy was struck by the great human mysteries of this world. He was almost fifteen, almost a man, and the great human mysteries of this world were striking him with satisfying regularity, as was correct for his stage of development. (From the Pathways Global Institute prospectus: “As our students reach tenth grade they begin to gain insight into the great human mysteries of this world, and a special sympathy for locals, the poor, ideologues, and all those who have chosen to limit their own human capital in ways that it can be difficult at times for us to comprehend.”) From the age of six months, when he was first enrolled in the school, he had hit every mark that Pathways expected of its pupils–walking, talking, divesting, monetizing, programming, augmenting–and so it was all the more shocking to find himself face-to-face with an almost nine-year-old so absolutely blind, so lost, so developmentally debased.
“This”–he indicated Felixstowe, from the beach with its turd castings and broken piers, to the empty-shell buildings and useless flood walls, up to the hill where his father hoped to expect him–“is nowhere. If you can’t move, you’re no one from nowhere. ‘Capital must flow.’ ” (This last was the motto of his school, though she needn’t know that.) “Now, if you’re asking me where I was born, the event of my birth occurred in Bangkok, but wherever I was born I would remain a member of the Incipio Security Group, which employs my father–and within which I have the highest clearance.” He was surprised by the extent of the pleasure this final, outright lie gave him. It was like telling a story, but in a completely new way–a story that could not be verified or checked, and which only total innocence would accept. Only someone with no access of any kind. Never before had he met someone like this, who could move only in tiny local spirals, a turd on a beach.
Moved, the boy bent down suddenly and touched the girl gently on her face. As he did so he had a hunch that he probably looked like the first prophet of some monotheistic religion, bestowing his blessing on a recent convert, and, upon re-watching the moment and finding this was so, he sent it out, both to Mr. Lin and to his fellow Pathways boys, for peer review. It would surely count toward completion of Module 19, which emphasized empathy for the dispossessed.
“Where is it you want to go, my child?”
“St. Jude’s!” she cried. She kept talking as he replayed the moment to himself and added a small note of explanatory context for Mr. Lin, before he refocussed on her stream of prattle: “And I’ll say goodbye to her. Whatever they said about her she was my own sister and I loved her and she’s going to a better place–I don’t care if she’s stone cold in that church, I’ll hold her!”
“Not a church,” the boy corrected. “14 Ware Street, built 1950, originally domestic property, situated on a floodplain, condemned for safety. Site of ‘St. Jude’s’–local, outlier congregation. Has no official status.”
“St. Jude’s is where she’ll be laid out,” she said and squeezed his hand. “And I’ll kiss her no matter how cold she is.” The boy shook his head and sighed. “We’re going in the same direction. Just follow me. No speaking.” He put his finger to his lips, and she tucked her chin into her neck meekly, seeming to understand. Re-starting, he flagged her effectively, transforming little Aggie Hanwell into his sidekick, his familiar, a sleek reddish fox. He was impressed by the perfect visual reconstruction of the original animal, apparently once common in this part of the world. Renamed Mystus, she provided cover for his left flank and mutely admired Bill Peek as he took the traitor Vice-President hostage and dragged him down the Mall with a knife to his neck.
After a spell they came to the end of the beach. Here the sand shaded into pebbles and then a rocky cove, and barnacles held on furiously where so much else had been washed away. Above their heads, the craft were finishing their sallies and had clustered like bees, moving as one back to the landing bay at the encampment. Bill Peek and his familiar were also nearing the end of their journey, moments away from kicking in the door to the Oval Office, where–if all went well–they would meet the President and be thanked for their efforts. But at the threshold, unaccountably, Bill Peek’s mind began to wander. Despite the many friends around the world watching (there was a certain amount of kudos granted to any boy who successfully met the President in good, if not record, time, on his first run-through), he found himself pausing to stroke Mystus and worry about whether his father would revoke his AG after this trip. It had been a bribe and a sop in the first place–it was unregistered. Bill had wanted to stay on at the Tokyo campus for the whole summer, and then move to Norway, before tsunami season, for a pleasant fall. His father had wanted him by his side, here, in the damp, unlit graylands. An AG 12 was the compromise. But these later models were security risks, easily hacked, and the children of personnel were not meant to carry hackable devices.
Previously the boy had believed that the greatest testament to love was the guarantee–which he had had all his life-of total personal security. He could count on one hand the amount of times he’d met a local; radicals were entirely unknown to him; he had never travelled by any mode of transport that held more than four people. But now, almost adult, he had a new thought, saw the matter from a fresh perspective, which he hoped would impress Mr. Lin with its age-appropriate intersectionality. He rested against the Oval Office door and sent his thought to the whole Pathways family: “Daring to risk personal security can be a sign of love, too.” Feeling inspired, he split the visual in order to pause and once more appreciate the human mysteries of this world slash how far he’d come.
He found that he was resting on a slimy rock, his fingers tangled in the unclean hair follicles of Agatha Hanwell. She saw him looking at her. She said, “Are we there yet?” The full weight of her innocence emboldened him. They were five minutes from Ware Street. Wasn’t that all the time he needed? No matter what lay beyond that door, it would be dispatched by Bill Peek, brutally, beautifully; he would step forward, into his destiny. He would meet the President! He would shake the President’s hand.
“Follow me.”
She was quick on the rocks, perhaps even a little quicker than he, moving on all fours like an animal. They took a right, a left, and Bill Peek slit many throats. The blood ran down the walls of the Oval Office and stained the Presidential seal and at the open windows a crowd of cheering, anonymous well-wishers pressed in. At which point Mystus strayed from him and rubbed herself along their bodies, and was stroked and petted in turn. “So many people come to see your Maud. Does the soul good.”
“How are you, Aggie, love? Bearing up?”
“They took her from the sky. Boom! ‘Public depravity.’ I mean, I ask you!” “Come here, Aggs, give us a hug.”
“Who’s that with her?”
“Look, that’s the little sis. Saw it all. You go straight through. You’ve more right than anybody.”
All Bill Peek knew is that many bodies were lying on the ground and a space was being made for him to approach. He stepped forward like a king. The President saluted him. The two men shook hands. But the light was failing, and then failed again; the celebrations were lost in infuriating darkness. . . . The boy touched his temple, hot with rage: a low-ceilinged parlor came into view, with its filthy window, further shaded by a ragged net curtain, the whole musty hovel lit by candles. He tried to locate Agatha Hanwell, but her precise coordinates were of no use here; she was packed deep into this crowd–he could no more get to her than to the moon. A distressing female with few teeth said, “Leave him be.” Bill Peek felt himself being pushed forward, deeper into the darkness. A song was being sung, by human voices, and though each individual sang softly, when placed side by side like this, like rows of wheat in the wind, they formed a weird unity, heavy and light at the same time. “Because I do not hope to turn again . . . Because I do not hope . . .” In one voice, like a great beast moaning. A single craft carrying the right hardware could take out the lot of them, but they seemed to have no fear of that. Swaying, singing.
Bill Peek touched his sweaty temple and tried to focus on a long message from his father–something about a successful inspection and Mexico in the morning–but he was being pushed by many hands, ever forward, until he reached the back wall where a long box, made of the kind of wood you saw washed up on the beach, sat on a simple table, with candles all around it. The singing grew ever louder. Still, as he passed through their number, it seemed that no man or woman among them sang above a whisper. Onward they pushed him; he saw it all perfectly clearly in the candlelight–the people in black, weeping, and Aggie on her knees by the table, and inside the driftwood box the lifeless body of a real girl, the first object of its kind that young Bill Peek had ever seen. Her hair was red and set in large, infantile curls, her skin very white, and her eyes wide open and green. Yet none of it struck him quite as much as the sensation that there was someone or something else in that grim room, both unseen and present, and coming for him as much as for anybody. | 5,644 | common-pile/pressbooks_filtered | https://pressbooks.nvcc.edu/eng236/chapter/meet-the-president/ | pressbooks | pressbooks-0000.json.gz:77640 | https://pressbooks.nvcc.edu/eng236/chapter/meet-the-president/ |
h4nG9GGsng1bmv2u | 36.1: Review of the Female Reproductive System | 36.1: Review of the Female Reproductive System
By the end of this section, you should be able to:
- 36.1.1 Describe the structure and function of the female reproductive system.
- 36.1.2 Discuss common conditions that affect the female reproductive system.
Structure and Function of the Female Reproductive System
The female reproductive system (also referred to as the ovarian reproductive system ) is made up of internal and external organs (see Figure 36.2). The external parts, known also as the vulva (see Figure 36.3), include the labia majora, labia minora, clitoris, vaginal and urethral openings, and the mons pubis. The internal organs are the vagina, cervix, uterus, fallopian tubes, and ovaries (Hoare & Kahn, 2022; Netter, 2022).
The labia majora provide protection to the other external organs. The labia minora cover the openings to the urethra and the vagina. The clitoris is the junction of the labia minora and is the organ that allows sexual arousal to occur. Pubic hair grows from the mons (Hoare & Kahn, 2022; Netter, 2022).
The uterus, or womb, is where a fertilized egg implants to develop into the fetus. If an egg is not fertilized and implanted, the uterus sheds its inner lining in the process usually known as menstruation or a period. The vagina is the birth canal, which connects the cervix, the lowest end of the uterus, to the outside of the body. During labor, the cervix gradually dilates to allow the fetus to enter the vagina. Strong contractions push the fetus through the vagina to the point where the fetus is born, meaning it has been delivered outside the body (Betts et al., 2023; Hoare & Kahn, 2022; Netter, 2022).
Hormones
The major hormones affecting the female reproduction system are secreted from three locations in the body. The hypothalamus secretes a hormone known as the gonadotropin-releasing hormone (GnRH) . The anterior pituitary is stimulated by GnRH to secrete two hormones: Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) . Finally, the ovaries (gonads) themselves secrete estrogen and progesterone (gonadotropins) in response to FSH and LH released by the anterior pituitary. Each of these hormones is released during the monthly menstrual cycle, but in different amounts depending on the stage of the cycle. Estrogen and progesterone are gonadotropins.
GnRH is a critical hormone in the hypothalamic-pituitary-gonadal axis, acting as the central regulator. It is responsible for regulating the start of puberty, onset of menstrual cycle, development of sex characteristics, and ovulation. GnRH is also responsible for producing the gonadal sex hormones, LH and FSH (Casteel & Singh, 2023).
FSH and LH stimulate the development of ovarian follicles and the release of mature ova (eggs) from mature follicles. Additionally, FSH and LH prepare the body for pregnancy and support pregnancy until the time of delivery.
Estrogen is produced in three types: estradiol, estriol, and estrone. It initiates the development of the female genitalia and breast tissue and plays many roles during pregnancy to conserve energy for the fetus, increase metabolism, increase uterine motility, and other actions to prepare the body for pregnancy and delivery. Progesterone performs many of the same functions as estrogen does, to promote maturation of sex organs, prepare the body for pregnancy, and maintain a healthy uterine environment for development of the fetus.
The adrenal cortex secretes gonadocorticoids (gonadotropins), which are the sex hormones. Male hormones (androgens/testosterone) and female hormones (estrogen) are secreted in opposite sexes in very small amounts. However, they have minimal effect on the opposite sex (testosterone in females and estrogen in males) because hormones from the testes and ovaries override them. In menopause, androgen has more of a masculinization effect on females because the ovaries secrete less estrogen (Nassar, 2023).
Menstrual Cycle
The menstrual cycle refers to the monthly changes in hormones and reproductive organs that usually occurs on a 28-day cycle. The length of the cycle is different for each client and may be shorter or longer or even irregular for some individuals. The first menstrual cycle is known as menarche and generally begins around age 12, with some clients starting earlier and some not starting until their mid-teens. Each menstrual cycle begins with the first day of bleeding from the uterus. The bleeding is the discharge of blood and endometrial tissue, the lining of the uterus, which had been prepared for the implantation of a fertilized egg. Bleeding lasts around 5 days, though the length of time is individualized. Approximately 14 days after the first day of the cycle, ovulation occurs. The ovary releases an egg, and it travels through the fallopian tubes to the uterus to be fertilized and implanted. If no fertilization occurs, the egg, along with the endometrial content, is expelled from the uterus, and the bleeding starts another menstrual cycle (McLaughlin, 2023; Rosner et al., 2022).
Hormones play a key role in the menstrual cycle through increased or decreased secretion from the hypothalamus, anterior pituitary, and ovaries. At the start of each cycle, the ovaries increase the production of estrogen until about day 14, when ovulation occurs; estrogen production then sharply decreases. During the second half of the cycle, estrogen secretion increases until about day 20 and then decreases to its lowest point when menstruation restarts, marking day 1 of a new cycle. Progesterone secretion, in contrast, is low until just before ovulation and then increases sharply, reaching a peak on about day 20. It then decreases gradually and remains low until the next ovulation at days 12–14 (McLaughlin, 2023; Rosner et al., 2022).
GnRH, LH, and FSH stimulate target cells (the cells that respond to a specific hormone) in the ovaries, causing the increased production of estrogen and progesterone. The hormone GnRH is secreted in bursts that vary in amplitude and frequency. The variations of amplitude and frequency also impact the start of other hormonal changes that regulate the menstrual cycle. Testosterone and progesterone decrease the frequency of GnRH bursts, whereas estrogens increase the frequency (Casteel & Singh, 2023). Additionally, LH and FSH increase the number and size of the target cells. Both LH and FSH secretion rise slightly at the start of the menstrual cycle, decrease, and then sharply increase immediately before day 14, or ovulation. They decrease significantly and rapidly after ovulation and remain steady until just before the start of a new cycle (McLaughlin, 2023; Rosner et al., 2022).
Figure 36.4 shows the phases of hormonal secretion.
Link to Learning
Dr. Paulien Moyaert is a Belgian nuclear medicine resident and science communicator. In this video, Dr. Moyaert explains the hormonal changes that occur during the menstrual cycle .
Pregnancy
Pregnancy means that an egg produced by the ovary has been released, fertilized by sperm, and implanted into the lining of the uterus and has begun to grow into a fetus. During pregnancy, the client will not have monthly menstrual cycles.
Three main groups of medications are related to pregnancy and will be discussed later in the chapter: contraceptives for clients who do not want to become pregnant, fertility medications for females who need help to become pregnant and maintain the pregnancy, and medications used during labor and delivery.
Menopause
Once a client has passed the age when they have regular monthly cycles, they have entered perimenopause . During perimenopause, the monthly menstrual cycle generally becomes irregular. A client may experience a missed cycle for one month and then have a period the following month. Cycles may occur closer together, the actual bleeding time may be shorter, and the amount of bleeding may decrease. Menopause is diagnosed once a client has not had any monthly cycles for 12 consecutive months (Peacock & Ketvertis, 2022; Mayo Clinic, 2023b; North American Menopause Society (NAMS) 2022 Hormone Therapy Position Statement Advisory Panel, 2022).
Menopause can occur in a client as early as their 30s until their mid-50s, with an average age of 51 years. Clients who experience menopause younger than age 40 are considered to have early menopause, usually the result of a genetic or chromosomal problem. Surgical menopause happens when the ovaries are surgically removed. Additionally, induced menopause may occur as the result of medications or radiation therapy that damages the ovaries. Whatever the reason for menopause, the signs and symptoms will be the same (Peacock & Ketvertis, 2022; Mayo Clinic, 2023b; NAMS 2022 Hormone Therapy Position Statement Advisory Panel, 2022).
During menopause, certain conditions develop that are the result of decreased hormones, specifically estrogen and progesterone. Vaginal dryness, hot flashes, night sweats, mood changes, weight gain, trouble sleeping, and thinning hair are what most clients experience during menopause. The intensity of each menopausal condition is individualized, so comparing one person’s experience to another person’s is not supportive to individual clients (Hariri & Rahman, 2023; NAMS 2022 Hormone Therapy Position Statement Advisory Panel, 2022; Mayo Clinic, 2023b; Peacock & Ketvertis, 2022).
One primary concern of menopause is the loss of bone mass, which can lead to fractures. This topic will be covered in more detail in the next section.
Link to Learning
Dr. Jen Gunter discusses what happens to the bodies of clients during menopause. | 1,956 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Nursing/Pharmacology_for_Nurses_(Openstax)/36%3A_Reproductive_Health_Drugs/36.01%3A_Review_of_the_Female_Reproductive_System | libretexts | libretexts-0000.json.gz:15313 | https://med.libretexts.org/Bookshelves/Nursing/Pharmacology_for_Nurses_(Openstax)/36%3A_Reproductive_Health_Drugs/36.01%3A_Review_of_the_Female_Reproductive_System |
U9mKdYDQgKvttLVI | Report of the chief engineer on the survey of the N.C. Railroad, May 1851. | NORTH CAROLINA RAILROAD.
At a meeting of the Directors of the North Carolina Rail Road Company, at Raleigh, had on the 12th and continued to the 16th of May, the Report of the Chief Engineer, of the Survey and Location of the said Road was made to the Board and adopted, and ordered that three thousand copies of said Report be printed for distribution.
The line of the Road, as recommended by the Chief Engineer, commences at the Wilmington and Raleigh Rail Road, passes by Waynesboro', crossing the Neuse about four miles above Smithfield, by Raleigh, Crabtree Bridge, Hillsborough Graham, Greensborough, Lexington, Salisbury, Concord, to Charlotte— 223 miles in length.
It was further ordered, that the President and Chief Engineer let the contracts for all the grading, masonry, bridging, and timber for superstructure, to be completed by the 1st of January, 1854, unless longer time be given by the Board.
Acting under your instructions to me of July 18th, 1 proceeded to organize four parties of Engineers. To give efficiency to these parties devolve due responsibility, and incite a laudable emulation, I gave to each party acting under my instructions a separate and independent charge, and to this end the line was divided into four divisions.
The First Division commences at the Wilmington and Raleigh Rail Road and terminates six and a half miles west of Raleigh The Second Division commencing at the last named poinCextends to the Guilford County line. The Third Di;-ision thence to Lexington, and the Fourth Division from Lexingfcofi to Charlotte. The duty of surveying and locatmgtnese divisions, was assigned respectively to Mr. Lewis M Provost. Jr., Mr. John C. McRae, Mr. J. L. Gregg, and Mr John McRae, with the rank of Principal Assistants. Each party was furnished with the necessary Assistants, Draftsmen, Rodmen, Chainmen, and Axemen.
of August.
The aggregate number of miles run by these parties, including the experimental surveys, the approximate and final location, amounts to 1494 miles. When it is remembered that the period of their employment embraced the inclement season of the late fall months, and the winter and early springmonths, the amount of labor they have performed cannot but prove satisfactory, and it fully attests the energy, industry, and fidelity on the part of the heads of the respective parties.
The condition imposed by the Charter, make Raleigh and Salisbury intermediate points in the line of the road. By a resolution of the stockholders at their meeting held in Salisbury on the 12th of July, instructions were given to ascertain )y' actual survey whether a route passing near the Towns of Hillsboro', Graham, Greensboro', Lexington and Concord, all things considered, would not be the most practicable. Keeping these instructions before me, regarding them however as. imperative only so far as respects the requirements of the Charter, to construct a Rail Road from ths Wilmington and Raleigh Rail Road via Raleigh and Salisbury to Charlotte, and only as absolute under the directions of the stockholders to ascertain the practicability in comparison with other routes, of a location through the towns of Hillsboro', Graham, Greensboro', Lexington and Conord, and not by any means as restricting the location to those towns. The line would occupy precisely the ground which it does had no allusion to those towns been made in the proceedings of the stockholders. I explored or caused to be examined every route between- the , Wilmington and Raleigh Rail Road, and Charlotte via Raleigh and Salisbury, which I thought at all feasible, and sur- ' veyed every line that in my judgment was deemed necessary to the attainment of the most practicable route, and the results of those examinations it is now my purpose as briefly as may be to lay before you. But it may be pertinent before entering upon a description of the lines which were surveyed, to submit a few remarks upon the general features of the inter-
mediate country between Raleigh and Salisbury, and their influence upon the location. An inspection of the map of tho State -will shew that a straight line between Raleigh and Salisbury is crossed by the waters of the Haw and Yadkin rivers, and by their almost innumerable tributaries, embracing among the most conspicuous, with their branches, New Hope, Rocky Deep and Uharie rivers. Any one who has travelled the direct road from Raleigh to Salisbury, by Pittsboro' and Ashboro', must have indelibly impressed on his mind the many uups and downs" which he encounters, and it must have occurred to him when slowly climbing up the hills which ever and anon rise before him, how much the road might be improved by winding around them through some of the numerous ravines ' which constantly present themselves on the one hand or the other. These hills which so much obstruct the common road, 4 and the graduation of which to easy grades, would render it so serpentine and devious, and carry it so much out of the direct eours'e, would affect in a much greater degree the route of a rail road ; no line of any extent either level or of a given inclination to the horizon could be maintained, without resorting to a continued succession of heavy cuttings and fillings, and an infinite series of abrupt curves. In many places the ridges and hills that would be crossed are composed of gravel intermixed with stones and not unfrequently they are formed entirely of rock, which would add greatly to the expense of graduation.
The extent of these difficulties may be regarded as unlimited on the South towards which the water courses that are crossed flow ; in search of a route, on the North, there is no medium short of the sources or nearly so of the principal tributaries above mentioned of the Haw and the Yadkin. Being satisfied, therefore, that no line could be obtained on the direct route without such frequent deflections as would make it quite as long, that it would be more costly and objectionable both in grades and curvature, than the route around the heads of the water courses before mentioned, that no intermediate route could be found, and that a survey of the direct route would be
attended with no "better results than loss of time and unnecessary expenditure, I determined to abandon it at once, and make the detour of the ridge, so plainly indicated by the topography of the country as the route for the rail road, which I shall now proceed to describe under four separate heads, corresponding to the four divisions of the line heretofore defined..
FIRST DIVISION.
This Division unites the North Carolina Rail Road with the Wilmington and Raleigh Rail Road, thus forming a continuous line from the Seaboard through the heart of the State and reducing to realization the long deferred hopes of the advocates of a Central Rail Road.
The Charter requires that the Rail Road shall connect with the Wilmington and Raleigh Rail Road, "where the same passes over the Neuse. " The bridge of the Wilmington and Raleigh Rail Road, over the Neuse, is united to the main land on each side by trestle work across extensive low grounds, subject to frequent inundations, which affords no secure site for a landing or suitable place for building. As this provision of the charter was evidently intended to unite the Rail Road with Steamboat Navigation on the Neuse, and. thus extend its benefits and a participation of. its advantages -to the lower Neuse, I have on account' of the objections above assigned to a strict compliance with the letter of the charter, directed the approach to the Wilmington and Raleigh Rail Road, by the way of Waynesboro', which affords the nearest eligible site to the point, where the Wilmington and Raleigh Rail Road passes the Neuse, for a landing. Here the channel washes the base of a high bank which is rarely if ever overflowed, affording every necessary facility for transhipment. Making Waynesboro' therefore, a point in the location, three lines were run from station 228, four and a half miles west of Goldsboro', to the Wilmington and Raleigh Rail Road, one by the way of Goldsborough, and thence to Waynesboro', making Waynesboro' the terminus of the ::ad. One by Waynesboro' to Goldsboro* di-
These lines are all laid down on the accompanying map in the order here referred to, lettered A, B, and C, and a comparison of their cost, length and grades will he found on a sheet hereto annexed, upon an examination of which it will be found, that the line passing through Waynesboro' and intersecting the Wilmington and Raleigh Rail Road 1.08 mile south of Goldsboro', designated as C, on the map, is 8,887 feet shorter and will cost §10,277 less than line A, which stands next in the -comparison. Commencing at station 228, the point -of divergence of the routes above described, two lines were run to Mount Auburn, ten miles East of Raleigh, one crossing the Neiise river at Smithfield, the other crossing on the lands of Mr. Yinsons four miles above Smithfield. The result shows 1 mile, 1720 feet in distance and $11,000 in cost in favor of the line by Yinsons' ; the rate of grade and length of straight line, is also hi favor of this route ; it was therefore selected as the basis of the estimate and is designated on the map by the red line.
From Mount Auburn, after a most thorough examination and survey of the country, with a view of obtaining the best route. through the City of. Raleigh, three lines were selected for comparison which will be designated as the South, middle and North lines. The South line runs down wild Cat branch, crosscsWalnut creek,near Holleman's bridge and runs up Rocky branch to its head, passing in the rear o?the Governor's and Judge Cameron's residences, and thence in the vicinity of the Hillsboro' road to the end of this division, six and a half miles Wrest of Raleigh.
The middle line descends Poole's branch to its junction with Walnut creek, and after crossing Walnut creek near Mr. Hutchins', it ascends along the slope of the ridge between Walnut and Crabtree, to its summit in the race field, thence it follows nearly the course of the ridge, passes South of Mr. Atkinson'a and through Raleigh by Hargett street to its re-union with the South line at Judge Cameron's?,
The North line is indentical with the middle line, until it reaches a point "between the race-field and Mr. Atkinson's, it then runs a little South of Mr, Atkinson's and through Lane street by the Raleigh and Gaston Rail Road Depot, back of the Female Seminary and connects with the middle and Southern lines near the Haywood road on the lands of Dr. Cook. It appears from a comparison of these lines as exhibited in the accompanying table, that the South linei3 1875 feet shorter and that the cost of graduation and construction is $6788 less than on the Middle line, and that in comparison with the Northern line, the length is 2175 feet and the cost is $45,029 in its favor. The maximum grade is the same on all these lines, the grade being rather in favor of the Middle route ascending westward and about the same in both directions as the Northern line. The curvature is also in favour of the South line as compared with both of the other lines.
A line was also run uniting the South and North line through Harrington street, which increased the distance over the South line 2750 feet and the cost $25,511.
The cost distance and degree of curvature being; all in favor of the South line, I am compelled in a professional point of view to give it my preference. There are other considerations however which may properly influence the Board, such as the pror priety, probably the necessity and obligation of the Company, to put a depot within the corporate limits of Raleigh, which would be attended with no serious objections so far as the grades of the road are concerned on the Middle line ; while on the South line the road ascends with a uniform grade of 47 J feet per mile past Raleigh, upon which the establishment of a depot would be very objectionable, on account of the difficulty of stopping the descending and starting the ascending trains, and this objection can only be removed by introducing a lighter grade which can in no other way be effected than by increasing the rate of ascent from Walnut Creek, which would operate against this line ;but as the grade would be in favor of the heavy tonnage, it would still maintain its superiority over the middle lineRecurring again to the commencement of the line at th&
Wilminton and Raleigh Rail Road, I would recommend the eetaplishment of the Depot at Goldsboro', instead of at the point of connection of the roads — for the reasons that tha Wilmington and Raleigh Rail Road Company having warekouses alreay erected at Goldsboro', could without additional expense to them give accommodations that would be a saving to the Company.
After several trial lines across Crabtree creek which is encountered six miles from the commencement of this division, a line was selected crossing at Mr. Jere. Morris', thence it aseends along the sloping ground drained into Crabtree to Mr. Robt. Witherspoon's on the ridge dividing the waters of New Hope and Neuse Rivers, thence the line pursues this ridge, departing from it only at one place to maintain the general direction and at the same time avoid the Brasfield hills which are passed, leaving them a half a mile on the North, 'at a trifling expense encountered in embanking across two small branches of New Hope. At Desarne's, ten miles east of Hillsboro', two routes present themselves, one pursuing the ridge dividing the waters of the Eno and New Hope rivers, forming an independent line crossing Haw river at Gilbreath's ford, and thence to Providence meeting house, designated on the map as the Chapel Hill ridge line. The other passes by Hillsboro,' and crossing Haw river at Trollinger's bridge re-unites with the other at Providence meeting house. These routes may be united by a cross line on the ridge dividing the waters of the Eno and Haw rivers by a deflection from the first line at Gravelly Hill, and thus the various routes crossing Haw river, which will hereafter be described, may be made a part of either line and a comparison between the two be , made ; adopting either of the crossings of the river. Suffice it to say, however, that the result by any combination that could be made would be in favor of the route by Hillsboro', in all the essentials of grades, cost, curvature and distance. I shall therefore dismiss the Chapel Hill route, as it is designated on the map, and con-
fine my observations to the Hillsboro' route, which after it became evident that it would be the preferred route, was subjected to the most elaborate explorations and surveys. The first important enquiry was the pass of the Valley of the Eno, the result of which was the establishment of a crossing at the upper end of the town of Hillsboro' and again just below the bridge near Brown's Mill, thence the line ascends along the side hills of Seven Mile Greek to the ridge dividing the waters of the Eno from those of Back creek, a branch of Haw river, and along this ridge it is traced to the vicinity of the Orange and Alamance- county line. From this point to the Haw^iver a thorough reconnoisance of the country was made and the river examined from the Shallow Ford to Ruffin's Mills. The result of this reconnoisance was the selection of four line's crossing. Haw River respectively at Gilbreath's ford, at the mouth of Freeland's creek, Conrad Long's and near Trollingers bridge, all uniting at Providence Meeting House. The first line was abandoned on account of its increased length and cost, and the second for the same reasons and in addition thereto in consequence of its objectionable curves and the heavy rock excavations between Back Creek and Haw River. This narrowed down the choice between the two routes crossing at Long's and at Trollinger's bridge, noted on the map as the upper and the lower lires. A comparison of these lines gives the following results viz: The upper line costs less by $5,000 and the length is one mile less than the lower line. The lower line has less curvature of the minimum radius and the' length of the maximum grades is less, but these favorable features not being sufficient to counterbalance its increased length and cost, I give the upper line the preference and recommend its adoption. From Providence Meeting House, the line of this division is traced over very favourable ground along the ridge dividing the wa- ' ters of Haw and Alamance rivers, to its termination on the dividing line between Alamance and Guilford counties.
With the view of cutting off the detour, on the route by Hills-' 'boro', around the head of New Hope, a line was reconnoitred diverging at Parris Yates, on this division, one and a half miles
fvora its commencement, passing around the head of Crabtree and by Mr. BartJey Sears' eight miles from Yates', thence along a ridge dividing the waters of North East, New Hope and and White Oak Swamp to Mr. Marmaduke Williams', where it crosses New Hope, thence on a ridge between Morgan's and Boiling's creeks, to a point about two miles from Chapel Hill, where the -ridge, upon which the College is situated rises very abruptly ; to ascend to the summit of this ridge either Morgan's or Boiling's are available; having attained the summit, at Mr. Arch. Andrew's,, owing to the necessity of exceeding our maximum grades in the passage of Cain and Haw creeks, the line would be compelled to follow the ridge heading these creeks, until it intersects the line heretofore described as the Chapel Hill ridge line, near Mr. Fred. William's, and thence with that line as run. Owing to these frequent deflections this route, although called the direct route, would be about two miles longer than the line by Hillsboro,' and a comparison of the grades, curvature and cost would also be against it. This being the result of the reconnoisance, it was not thought advisable to incur the expense of a survey.
This division begins on the Alamance and Guilford lines, about one and a half miles north of the stage road on the ridge dividing the waters of Traverse creek from those of xllamance, and continues on this ridge about two miles, thence it descends the Valley of Rock creek which it crosses at its junction with Cedar prong, thence upon the south slope of Cedar prong valley to the summit of the ridge, dividing its waters from Birch creek, thence along the South slope of the ridge, dividing Alamance and South Buffaloe creeks, crossing it at the intersection of the Shallowford and Fayetteville roads. The line then descends to south Buffaloe creek, crossing it about one thousand feet below the stage road bridge, thence it ascends to the ridge between North and South Buffaloe creeks on which it continues to Greensboro', crossing South street three hundred feet north of the Caldwell Institute, thence on the
ridge to station 928 near Mr. Nathan Hiatt's. From this point to Lexington, three lines present themselves for comparison— -which we will designate the Fair Grove, middle and Northern lines.
The Fair Grove and middle lines are common to Prospect meeting house ; before reaching this point the line crosses South Buffaloe near Mr.jjA. Wilson's, Bull Run a little below the stage road ford, and Deep river 1200 feet below the stage road bridge ; thence the line passes a little to the South of Jamestown, up the South prong of Big branch to station 1839, a quarter of a mile west of Prospect meeting house on the summit of the ridge between Deep river and the Yadkin. From station 1839 it continues heading nearly the waters of Hunt'B Fork, thence it descends along the South slope of the valley of Hambies' creek, crossing the Raleigh road near Fair Grove meeting house and continuing upon the north side of the road to a point near the house of Mr. Smith Curry, thence keeps near the Raleigh road and passes about 300 feet to the left of the Poor House, thence it descends to Abbott's creek, crossing it about three fourths of a mile below Randolph bridge; thence it passes up the south slope of the valley of Grimes' branch to the summit of the ridge between Abbott's and Swearing creeks near Parks', at the crossing of the stage road about 4,500 feet west of the Court House, where it joins the 4tb division.
The middle line diverges from the Fair Grove line at station 1839, crosses the head waters of Hunt's Fork to the ridge between Rich Fork and Hambie's creek, which it follows threo miles; thence it descends into the valley of Jimmie's creek to Conrad's old mill ; here the line crosses the creek and again makes two crossings at the bend opposite Mrs. Lopp's and passes over the point of ridge between Jimmie's creek and Rich Fork, crossing the latter near its junction with Hambie's creek, thence it crosses Abbott's creek about half a mile above the junction of Rich Fork, thence it passes down the valley of Abbott's creek, crosses Leonard creek near its mouth and thence along the sloping ground of Leonard's creek to Parka',
passing Lexington 1200 feet South of the Court House. This line may be straightened by a route leaving the line -which ie common to it and the Fair Grove line at station 1641, passing three fourths of a mile north of Prospect meeting house, and coming into the middle line again about 5 miles 1744 feet from the point of starting.
Northern line. This line deflects from the Fair Grove and middle lines, at station 928, at Hiatt's; thence it crosses South Buffaloe Creek, a little below the Salem road, it then ascends to the summit of the ridge between Haw and Deep rivers ; thence it descends Piney branch to its mouth, where it crosses the North prong of Deep river, thence passing over the ridge between the North and South prong, it crosses the South prong just below Chiprnan's mill. Thence it follows up Tan Yard branch to its head, thence crosses Rich Fork near its source and immediately ascends to the ridge between Abbott's creek and Rich Fork, along which it runs to Mr. Andrew Sink's on the stage road, where it commences descending and crosses Abbott's creek about half a mile below the stage road bridge and thence along the grounds of Abbott's creek to its re-union- with the middle line at station 2381. The length, curvature, grades, cost of construction and maintenance being in favor of the middle line, I give it preference and recommend its adoption.
of the Third Division above described.
The line passes through the far-famed fertile lands of the Jersey Settlement. Swearing creek and North Potts creek, which water these lands, are crossed, the 1st at Yarbrough's old mill and the second about a mile below Dr. Holt's mill on the lands of Dr. Holt, which furnish the best evidence on the line of the beneficial effects of a judicious combination of science and practical experience in farming. The second branch of Pott's creek is crossed at the Trading Ford road, and by a cut across this road, the line enters the Valley of the Yadkin,
which it pursues to station 2720 on the land of- Mr. T. McDonald. From this point two lines "were located across the Yadkin. The upper line crosses the river a little below Lock's bridge, on a bridge 60,0 feet long, 40 feet above low water and HO feet abovehigh water. The lower line crosses the river near the lower end of Cowan's Island, by a bridge 1000 feet long, 8 feet above high water and 24 feet above low water. I am not prepared to give an opinion as to the comparative advantages of these two lines and express my preference until a farther examination has been made, which will be done the first low stage of the water. I shall however,- .place in. the general estimates such, a sum as will embrace the cost and any contingencies of a farther examination. These two lines re-unite at station 2517 on the ridge near the heads of small branches of the Yadkin, and thence for a distance of '22-1 miles follows the ridge, keeping within the vicinity of the stage road. and passing at station 2815 the town of Salisbury. From station 1328 the line descends to .the valley of Irish Buffaloe and crosses the creek near the' old mill dam a quarter of a, mile below the public road and about a mile from the vilkge of Concord. Thence crossing Caudle creek and Rocky river, 4.63 and 5.78 miles respectively from Irish Buffaloe, the line passes over into the valley of Back creek^ and ascending the ridge between Back and Mallard creeks, the summit of which is gained near Col. Cochran's, it then follows the crest of the ridge from which it descends, crossing some of the head waters of the tributaries of Sugar creek, into the valley of one of the main branches of that creek, along which it is traced to a favorable point for crossing at station 132, thence to Charlotte passing on the southeastern side of the town to station 1049, the end of the Charlotte Bail Road.
The line above described is the result of a full reconnoisanee of the country and a comparison of the Cost, grades and length with a trial line between Lexington and the Yadkin, and it was also tested by the merits of a line from the vicinity of Concord to Charlotte, crossing Irish Buffaloe at Coleman's quarter and passing to the West of Back creek, by. different crossings of
to be objectionable.
In the above description of the several divisions I have omitted numerous lines that were surveyed and examined, which will be found in the memoirs of the Principal Assistants, herewith laid before you, and to which I beg leave to refer.
I supposed the stockholders might feel an interest.
The surveys have been made throughout in reference solely to the interests of the Company. It has been your pleasure to leave me free and untrammeled, with no other declaration of opinion on your part than an expression of your solicitude for the selection of the best and most practicable route, audit has been my most earnest desire to conform to your wishes ; no pains have been spared on my part and no labor has been wanting on the part of those entrusted with the duty of carry- ; ing into effect my instructions. The country has been thoroughly explored ; whenever any doubts existed they have been solved by instrumental surveys, and the competing lines tested and compared by well known and acknowledged principles, verified by experience ; nothing has been left to speculation* theory reduced to practice is the formula by which I have been governed in my efforts, in the language of the charter, to obtain the most practicable route for a rail road from the Wilmington and Raleigh Rail Road, via Raleigh and Salisbury, to the town of Charlotte.
I believe such a route is now presented to you, and that there is not a Rail Road in the country of the same length which possesses equal facilities for the economical application of Locomotive power. The grades nowhere exceed fifty feet per mile and curves of five degrees deflection adopted as the minimum, occur in but very few instances. The length of the road is 223 miles.
I have estimated for a single track with the condition of the ttaste earth being disposed and the borrowed earth taken by widening the cuts with a view to a double track, the Road be4
to be formed of gravel or other suitable material to the depth of a foot, and for a superstructure with a T-rail of sixty pounds to the yard. The drains and culverts are all to be built of stone or brick, and the wooden bridges to be on the most substantial plan of arch bracing, resting on stone abutments, and every description of work to be as permanent and durable as any of a similar kind in the country. The warehouses will be of wood.
The whole cost of the road on this plan, including engineering expenses, superstructure and land damages and every thing appertaining to the road way, will be $3,165,332.
In this estimate I have endeavored to provide for every possible contingency that may arise ; such as increase of labor and provisions, unforeseen difficulties in sinking foundations, and although the amount of rock excavation has been ascertained hj repeated borings on nearly the whole line, lest it might have been missed in our examination, I have made a liberal allowance for that contingency, also, so that I feel every confidence in stating the above sum as full and sufficient to cover all expenditures for the items therein embraced ; and, every tbi^g is included except the locomotives, cars and coaches and the shops for renewal and repairs.
The cost of the shop and fixtures may be put down at $100,000 though this whole of the expenditure will not bo necessary before the completion of the road ; it may be spread over two or three years after the road goes into operation.
The number of Locomotives and their trains depend of course entirely on the amount of business, and may be increased as the Wants of the company require. It is not usual to embrace in vhe original estimates and charge to capital more than barely sufficient to put the road into operation, and with inconsiderable additions, carry it through and enable it to do the business of the first year. "With this restriction I submit the Hollowing estimate, viz s
No difficulty or extraordinary expenditures will be encountered to any portion of the line in procuring substantial foundations for the works of art. The soil on every portion is peculiarly adapted to the formation of a dry and firm road bed ; timber for sills are found every where convenient to the line ; for several of the bridges, it will have to be transported a considerable- distance ; with this exception and the scarcity of good building rock at some points, suitable materials of every kind are found every where convenient to the line.
In relation to the income of the road I have no data, if it were my province to do so,upon which I would be willing to venture even a conjecture of the specific amount. But, upon a subject of so much importance to the stockholders it may be expected that I should say something, at least in relation to the prospects and just expectations that may be entertained by those who have embarked in it.
This rail road passes 'through the almost entire length of the State, it embraces in its route a variety of soil and productions not to be found on any railroad in the country. It commences in the rice fields on the Cape Fear and terminates in the cotton fields of the ancient and honored count}7 of Mecklenburg, traversing on its way a highly productive Grain, Tobacco and Cotton growing country. What is deficient on one part of the line to supply the wants of man is found on another, the raw material on one point will supply the manufacturers at another, who in turn will send out the wrought fabrics to the producer. The wheat and flour of the West will be exchanged for the products of the coast, and thus a reciprocal, growing and constantly inoreasing way trade will spring up,
which the history of railroads shew, is the most profitable bus^ ness ; indeed, that it is the only business that pays. Then there is the enterprising and flourishing town of Wilmington which may be regarded as the eastern terminus of the road, with her large "West Indian trade and varied commerce, giving her the ability to supply the wants of the producers and creating a constant demand for the productions, and the markets of Virginia thrown open by their Raleigh, and Gaston. Rail Road, with their demands and means of supply, all uniting to stimulate industry and production arid thus add such an amount of tonnage and business to the road as to render it almost unnecessary to look beyond its limits for the sources of its productive-, ness. But, if we were permitted to look abroad, we could with quite as much plausibility of argument as we see urged, every day, in connection with other schemes, place this one also m communication with Memphis, which seems to be regarded by many as a point on the great high way to. the Pacific, and we could then without any very great stretch of the imagination, extend this road to Beaufort, and fancy her safe and secure harbor crowded with shipping from ail parts of the world.. Such speculations would probably not be considered rational, though far within the bounds of the visions which fill the mind of the projectors of Rail RjO.ads possessing nothing like the probabilities of accomplishment as would seem to attend the yery reasonable project of extending the North Carolina Road into Tennessee and down to Beaufort.
And why should not North Carolina accomplish this enterprise ? X believe she will; she has already authorised surveys to ascertain the cost of extending the road over the mountains and granted a charter for a Rail Road to Newbern ; both schemes are entirely feasible and practicable, and will at no distant day, I have no doubt, be accomplished.' They are probable in theory, and what is. probable in theory has in practice always proved true. But these schemes are in the future, although in my opinion in the certain future. I prefer reasoning from the past and grasping what is before me. Rooking, then, as I have said, to, the wide spread demand &$&
to the ability and capacity of the Country on the immediate borders of the road to supply that demand, I have no fears of the result & feel in no need- of travelling beyond the borders of the State in search of trade and travel to demonstrate the pro* ductiveness of the Stock of the North Carolina Hail Road. I am, however, not indifferent to the income arising from the through business; it is. one of the certainties of the present which I count largely upon from our connection with the Charlotte and South Carolina Rail Road, Having, however, in the outset confined myself to the limits of the road, and to a simple statement of its influences in promoting home indus-: try, and thereby adding to the wealth of the State, and creating business for itself — I have, although entertaining just expectations, not felt myself at liberty to draw heavily from other sources— J prefer leaving that branch of the estimate to o-. thers quite as competent to the computation as myself, to make such additions as may suit their views.
The effect of rail roads every where is to increase the value of lands. The ratio of increase is dependent upon the fertility of the Soil and the remoteness of the lands from market, and the amount of increase is exactly the capitalized sum which the saving in the transportation upon the annual produce of an acre would give. For instance, if the annual saving in the transportation of the produce of an acre of land is one dollar,, the value of the land will be increased $10,2-3, the capital which at six per cent, would yield a dollar. My own impression is that the lands on the line of the North Carolina Rail Road will be increased in a greater ratio than this, now universally acknowledged principle of computation would give, forthe reason that they are from some cause greatly underrated, especially from Lexington to Charlotte ; the lands on this portion of the road which grow Cotton as well as Grain, compared with lands in Virginia similarly situated in reference to markets and which grow only grain and grass, are valued at very little more than half the price of the lands in Virginia. The effect of the Rail Road will be to raise these lands to their proper standard of value and add also thereto the ep..-
portation.
The manufacturing establishments on the line of the work, which are now in a comparatively feeble and declining condition, will receive an impulse that will reward their enterprising proprietors, and revive the drooping hopes of the advocates of home industry. For it must be obvious to every one how. much they are affected by the cost of transportation.
The expense of transporting the raw material, and manufactured goods, constitutes an element in the cost of those goods in market. The means of transportation are in fact but a part of the machinery in the manufacture of goods for market, and the same principle applies as well in the improvement of the one 'as in the other. The man with good machinery can manufacture profitably and sell at a price at which the one Avith poor machinery would be ruined. If then we apply this principle to the transportation of the raw material, bread stuffs, and other a rticles of consumption in manufacturing establishments, it needs no argument or calculation to shew that he who can make use of a Rail Road for this purpose can always undersell those who are without the accommodation. This is the true secret of the success of the Northern manufactories ; the liberal system of internal improvement at the iTorth has cheapened the transportation of their supplies. I doubt not, it would prove upon investigation, that the transportation of a bag of Cotton from the interior of Georgia in the vicinity of her rail road to Lowell, costs less than the transportation to many of the manufactories in N. Carolina, within a hundred miles of the Cotton fields.
The reduction in the price of transportation must be attended at least with the working of the existing establishments up to their full capacity, and with their success the erection of others will follow, until in course of time the State will become a manufaturing and by consequence a consuming as well producing State.
est which is the great interest of the btate. And thus the great ends of government will be accomplished by the silent workings of the system of internal improvements, without doing violence to the theories or prejudices of any one. The greatest benefit will be conferred on the greatest number. In fact all willbe benefitted. For the North Carolina Rail Road is not a mere line of Railroad accommodating a single line of travel and operating on a narrow section of the State ; there is scarcely any portion or any interest in the State that is not benefitted by this work. It traverses nearly the whole length of the State, it is the Central Rail Road projected by the old and ardent friends of internal improvement, crossing the channels of some of the principal water courses, bringing their water falls and Manufactories into the actual vicinity of the Seaboard. It would be difficult to plan a work, so properly, so obviously and so essentially a State work. The people themselves have made it so by their wide spread and unprecedented individual sub scription of a million of dollars, and by their endorsement of the copartnership of the State from one end of it to the other, in her subscription of two millions more. That they will not be disappointed in their expectations, I am quite sure, unless it should turn out, and there is no reason why it should be so, that the same cause in North Carolina will not produce the same effects as in other States, North, South, East and West. In those States it is found that rail roads relieve the burden of taxation. First by the difference in the cost of transportation by common roads and by rail roads, which may be stated at about two to one. Secondly by increasing the taxable property on the line of the road, a general reduction of taxes is made, thus lessening the taxes on lands more remote, gives them an additional value, and thus the benefits of the road are extended far and wide, and are felt by the whole agricultural community. And furthermore, the general benefits which result to trade and commerce from railroads in other States extend to every portion of their territory ; every branch of industry is affected by the trade and commerce opened by these channels of communication. No one can doubt that the same
results will be experienced in North Carolina. In short, tkd feffect of a judicious system of internal improvement is to unite1 a State as it were in one great community with all their wants, demands and supplies brought to view, stimulating enterprize and industry in all the arts and various pursuits of man.
And last-, though not on this account the least, of the important benefits of the N. Carolina Railroad, is the effect it will have to withdraw the inducement to emigration which sve'ry year deprives the State of a portion of her most vigo= tfcus, enterprising and intelligent population. I am, gentlemen, very respectfully,
UNIVERSITY OF N.C. AT CHAPEL HILL
This book may be kept out one month unless a recall notice is sent to you. It must be brought to the North Carolina Collection (in Wilson Library) for renewal.
| 9,174 | common-pile/pre_1929_books_filtered | reportofchiefeng00nort | public_library | public_library_1929_dolma-0011.json.gz:3625 | https://archive.org/download/reportofchiefeng00nort/reportofchiefeng00nort_djvu.txt |
Ukj4nV2qrNmvc3TQ | Concepts of Biology - 1st Canadian Edition | Chapter 19. The Musculoskeletal System
19.2 Bone
charles-molnar and jane-gair
Learning Objectives
By the end of this section, you will be able to:
- Classify the different types of bones in the skeleton
- Explain the role of the different cell types in bone
- Explain how bone forms during development
Bone, or osseous tissue, is a connective tissue that constitutes the endoskeleton. It contains specialized cells and a matrix of mineral salts and collagen fibers.
The mineral salts primarily include hydroxyapatite, a mineral formed from calcium phosphate. Calcification is the process of deposition of mineral salts on the collagen fiber matrix that crystallizes and hardens the tissue. The process of calcification only occurs in the presence of collagen fibers.
The bones of the human skeleton are classified by their shape: long bones, short bones, flat bones, sutural bones, sesamoid bones, and irregular bones (Figure 19.16).
Long bones are longer than they are wide and have a shaft and two ends. The diaphysis, or central shaft, contains bone marrow in a marrow cavity. The rounded ends, the epiphyses, are covered with articular cartilage and are filled with red bone marrow, which produces blood cells (Figure 19.17). Most of the limb bones are long bones—for example, the femur, tibia, ulna, and radius. Exceptions to this include the patella and the bones of the wrist and ankle.
Short bones, or cuboidal bones, are bones that are the same width and length, giving them a cube-like shape. For example, the bones of the wrist (carpals) and ankle (tarsals) are short bones (Figure 19.16).
Flat bones are thin and relatively broad bones that are found where extensive protection of organs is required or where broad surfaces of muscle attachment are required. Examples of flat bones are the sternum (breast bone), ribs, scapulae (shoulder blades), and the roof of the skull (Figure 19.16).
Irregular bones are bones with complex shapes. These bones may have short, flat, notched, or ridged surfaces. Examples of irregular bones are the vertebrae, hip bones, and several skull bones.
Sesamoid bones are small, flat bones and are shaped similarly to a sesame seed. The patellae are sesamoid bones (Figure 19.18). Sesamoid bones develop inside tendons and may be found near joints at the knees, hands, and feet.
Sutural bones are small, flat, irregularly shaped bones. They may be found between the flat bones of the skull. They vary in number, shape, size, and position.
Bone Tissue
Bones are considered organs because they contain various types of tissue, such as blood, connective tissue, nerves, and bone tissue. Osteocytes, the living cells of bone tissue, form the mineral matrix of bones. There are two types of bone tissue: compact and spongy.
Compact Bone Tissue
Compact bone (or cortical bone) forms the hard external layer of all bones and surrounds the medullary cavity, or bone marrow. It provides protection and strength to bones. Compact bone tissue consists of units called osteons or Haversian systems. Osteons are cylindrical structures that contain a mineral matrix and living osteocytes connected by canaliculi, which transport blood. They are aligned parallel to the long axis of the bone. Each osteon consists of lamellae, which are layers of compact matrix that surround a central canal called the Haversian canal. The Haversian canal (osteonic canal) contains the bone’s blood vessels and nerve fibers (Figure 19.19). Osteons in compact bone tissue are aligned in the same direction along lines of stress and help the bone resist bending or fracturing. Therefore, compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions.
Which of the following statements about bone tissue is false?
- Compact bone tissue is made of cylindrical osteons that are aligned such that they travel the length of the bone.
- Haversian canals contain blood vessels only.
- Haversian canals contain blood vessels and nerve fibers.
- Spongy tissue is found on the interior of the bone, and compact bone tissue is found on the exterior.
Spongy Bone Tissue
Whereas compact bone tissue forms the outer layer of all bones, spongy bone or cancellous bone forms the inner layer of all bones. Spongy bone tissue does not contain osteons that constitute compact bone tissue. Instead, it consists of trabeculae, which are lamellae that are arranged as rods or plates. Red bone marrow is found between the trabuculae. Blood vessels within this tissue deliver nutrients to osteocytes and remove waste. The red bone marrow of the femur and the interior of other large bones, such as the ileum, forms blood cells.
Spongy bone reduces the density of bone and allows the ends of long bones to compress as the result of stresses applied to the bone. Spongy bone is prominent in areas of bones that are not heavily stressed or where stresses arrive from many directions. The epiphyses of bones, such as the neck of the femur, are subject to stress from many directions. Imagine laying a heavy framed picture flat on the floor. You could hold up one side of the picture with a toothpick if the toothpick was perpendicular to the floor and the picture. Now drill a hole and stick the toothpick into the wall to hang up the picture. In this case, the function of the toothpick is to transmit the downward pressure of the picture to the wall. The force on the picture is straight down to the floor, but the force on the toothpick is both the picture wire pulling down and the bottom of the hole in the wall pushing up. The toothpick will break off right at the wall.
The neck of the femur is horizontal like the toothpick in the wall. The weight of the body pushes it down near the joint, but the vertical diaphysis of the femur pushes it up at the other end. The neck of the femur must be strong enough to transfer the downward force of the body weight horizontally to the vertical shaft of the femur (Figure 19.20).
Concept in Action
View micrographs of musculoskeletal tissues as you review the anatomy.
Cell Types in Bones
Bone consists of four types of cells: osteoblasts, osteoclasts, osteocytes, and osteoprogenitor cells. Osteoblasts are bone cells that are responsible for bone formation. Osteoblasts synthesize and secrete the organic part and inorganic part of the extracellular matrix of bone tissue, and collagen fibers. Osteoblasts become trapped in these secretions and differentiate into less active osteocytes. Osteoclasts are large bone cells with up to 50 nuclei. They remove bone structure by releasing lysosomal enzymes and acids that dissolve the bony matrix. These minerals, released from bones into the blood, help regulate calcium concentrations in body fluids. Bone may also be resorbed for remodeling, if the applied stresses have changed. Osteocytes are mature bone cells and are the main cells in bony connective tissue; these cells cannot divide. Osteocytes maintain normal bone structure by recycling the mineral salts in the bony matrix. Osteoprogenitor cells are squamous stem cells that divide to produce daughter cells that differentiate into osteoblasts. Osteoprogenitor cells are important in the repair of fractures.
Development of Bone
Ossification, or osteogenesis, is the process of bone formation by osteoblasts. Ossification is distinct from the process of calcification; whereas calcification takes place during the ossification of bones, it can also occur in other tissues. Ossification begins approximately six weeks after fertilization in an embryo. Before this time, the embryonic skeleton consists entirely of fibrous membranes and hyaline cartilage. The development of bone from fibrous membranes is called intramembranous ossification; development from hyaline cartilage is called endochondral ossification. Bone growth continues until approximately age 25. Bones can grow in thickness throughout life, but after age 25, ossification functions primarily in bone remodeling and repair.
Intramembranous Ossification
Intramembranous ossification is the process of bone development from fibrous membranes. It is involved in the formation of the flat bones of the skull, the mandible, and the clavicles. Ossification begins as mesenchymal cells form a template of the future bone. They then differentiate into osteoblasts at the ossification center. Osteoblasts secrete the extracellular matrix and deposit calcium, which hardens the matrix. The non-mineralized portion of the bone or osteoid continues to form around blood vessels, forming spongy bone. Connective tissue in the matrix differentiates into red bone marrow in the fetus. The spongy bone is remodeled into a thin layer of compact bone on the surface of the spongy bone.
Endochondral Ossification
Endochondral ossification
is the process of bone development from hyaline cartilage. All of the bones of the body, except for the flat bones of the skull, mandible, and clavicles, are formed through endochondral ossification.
In long bones, chondrocytes form a template of the hyaline cartilage diaphysis. Responding to complex developmental signals, the matrix begins to calcify. This calcification prevents diffusion of nutrients into the matrix, resulting in chondrocytes dying and the opening up of cavities in the diaphysis cartilage. Blood vessels invade the cavities, and osteoblasts and osteoclasts modify the calcified cartilage matrix into spongy bone. Osteoclasts then break down some of the spongy bone to create a marrow, or medullary, cavity in the center of the diaphysis. Dense, irregular connective tissue forms a sheath (periosteum) around the bones. The periosteum assists in attaching the bone to surrounding tissues, tendons, and ligaments. The bone continues to grow and elongate as the cartilage cells at the epiphyses divide.
In the last stage of prenatal bone development, the centers of the epiphyses begin to calcify. Secondary ossification centers form in the epiphyses as blood vessels and osteoblasts enter these areas and convert hyaline cartilage into spongy bone. Until adolescence, hyaline cartilage persists at the epiphyseal plate (growth plate), which is the region between the diaphysis and epiphysis that is responsible for the lengthwise growth of long bones (Figure 19.21).
Growth of Bone
Long bones continue to lengthen, potentially until adolescence, through the addition of bone tissue at the epiphyseal plate. They also increase in width through appositional growth.
Lengthening of Long Bones
Chondrocytes on the epiphyseal side of the epiphyseal plate divide; one cell remains undifferentiated near the epiphysis, and one cell moves toward the diaphysis. The cells, which are pushed from the epiphysis, mature and are destroyed by calcification. This process replaces cartilage with bone on the diaphyseal side of the plate, resulting in a lengthening of the bone.
Long bones stop growing at around the age of 18 in females and the age of 21 in males in a process called epiphyseal plate closure. During this process, cartilage cells stop dividing and all of the cartilage is replaced by bone. The epiphyseal plate fades, leaving a structure called the epiphyseal line or epiphyseal remnant, and the epiphysis and diaphysis fuse.
Thickening of Long Bones
Appositional growth is the increase in the diameter of bones by the addition of bony tissue at the surface of bones. Osteoblasts at the bone surface secrete bone matrix, and osteoclasts on the inner surface break down bone. The osteoblasts differentiate into osteocytes. A balance between these two processes allows the bone to thicken without becoming too heavy.
Bone Remodeling and Repair
Bone renewal continues after birth into adulthood. Bone remodeling is the replacement of old bone tissue by new bone tissue. It involves the processes of bone deposition by osteoblasts and bone resorption by osteoclasts. Normal bone growth requires vitamins D, C, and A, plus minerals such as calcium, phosphorous, and magnesium. Hormones such as parathyroid hormone, growth hormone, and calcitonin are also required for proper bone growth and maintenance.
Bone turnover rates are quite high, with five to seven percent of bone mass being recycled every week. Differences in turnover rate exist in different areas of the skeleton and in different areas of a bone. For example, the bone in the head of the femur may be fully replaced every six months, whereas the bone along the shaft is altered much more slowly.
Bone remodeling allows bones to adapt to stresses by becoming thicker and stronger when subjected to stress. Bones that are not subject to normal stress, for example when a limb is in a cast, will begin to lose mass. A fractured or broken bone undergoes repair through four stages:
- Blood vessels in the broken bone tear and hemorrhage, resulting in the formation of clotted blood, or a hematoma, at the site of the break. The severed blood vessels at the broken ends of the bone are sealed by the clotting process, and bone cells that are deprived of nutrients begin to die.
- Within days of the fracture, capillaries grow into the hematoma, and phagocytic cells begin to clear away the dead cells. Though fragments of the blood clot may remain, fibroblasts and osteoblasts enter the area and begin to reform bone. Fibroblasts produce collagen fibers that connect the broken bone ends, and osteoblasts start to form spongy bone. The repair tissue between the broken bone ends is called the fibrocartilaginous callus, as it is composed of both hyaline and fibrocartilage (Figure 19.22). Some bone spicules may also appear at this point.
- The fibrocartilaginous callus is converted into a bony callus of spongy bone. It takes about two months for the broken bone ends to be firmly joined together after the fracture. This is similar to the endochondral formation of bone, as cartilage becomes ossified; osteoblasts, osteoclasts, and bone matrix are present.
- The bony callus is then remodelled by osteoclasts and osteoblasts, with excess material on the exterior of the bone and within the medullary cavity being removed. Compact bone is added to create bone tissue that is similar to the original, unbroken bone. This remodeling can take many months, and the bone may remain uneven for years.
Scientific Method Connection
Question: What effect does the removal of calcium and collagen have on bone structure?
Background: Conduct a literature search on the role of calcium and collagen in maintaining bone structure. Conduct a literature search on diseases in which bone structure is compromised.
Hypothesis: Develop a hypothesis that states predictions of the flexibility, strength, and mass of bones that have had the calcium and collagen components removed. Develop a hypothesis regarding the attempt to add calcium back to decalcified bones.
Test the hypothesis: Test the prediction by removing calcium from chicken bones by placing them in a jar of vinegar for seven days. Test the hypothesis regarding adding calcium back to decalcified bone by placing the decalcified chicken bones into a jar of water with calcium supplements added. Test the prediction by denaturing the collagen from the bones by baking them at 250°C for three hours.
Analyze the data: Create a table showing the changes in bone flexibility, strength, and mass in the three different environments.
Report the results: Under which conditions was the bone most flexible? Under which conditions was the bone the strongest?
Draw a conclusion: Did the results support or refute the hypothesis? How do the results observed in this experiment correspond to diseases that destroy bone tissue?
Summary
Bone, or osseous tissue, is connective tissue that includes specialized cells, mineral salts, and collagen fibers. The human skeleton can be divided into long bones, short bones, flat bones, and irregular bones. Compact bone tissue is composed of osteons and forms the external layer of all bones. Spongy bone tissue is composed of trabeculae and forms the inner part of all bones. Four types of cells compose bony tissue: osteocytes, osteoclasts, osteoprogenitor cells, and osteoblasts. Ossification is the process of bone formation by osteoblasts. Intramembranous ossification is the process of bone development from fibrous membranes. Endochondral ossification is the process of bone development from hyaline cartilage. Long bones lengthen as chondrocytes divide and secrete hyaline cartilage. Osteoblasts replace cartilage with bone. Appositional growth is the increase in the diameter of bones by the addition of bone tissue at the surface of bones. Bone remodeling involves the processes of bone deposition by osteoblasts and bone resorption by osteoclasts. Bone repair occurs in four stages and can take several months.
Exercises
- The Haversian canal:
- is arranged as rods or plates
- contains the bone’s blood vessels and nerve fibers
- is responsible for the lengthwise growth of long bones
- synthesizes and secretes matrix
- The epiphyseal plate:
- is arranged as rods or plates
- contains the bone’s blood vessels and nerve fibers
- is responsible for the lengthwise growth of long bones
- synthesizes and secretes bone matrix
- The cells responsible for bone resorption are ________.
- osteoclasts
- osteoblasts
- fibroblasts
- osteocytes
- Compact bone is composed of ________.
- trabeculae
- compacted collagen
- osteons
- calcium phosphate only
- What are the major differences between spongy bone and compact bone?
- What are the roles of osteoblasts, osteocytes, and osteoclasts?
Answers
- B
- C
- A
- C
- Compact bone tissue forms the hard external layer of all bones and consists of osteons. Compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions. Spongy bone tissue forms the inner layer of all bones and consists of trabeculae. Spongy bone is prominent in areas of bones that are not heavily stressed or at which stresses arrive from many directions.
- Osteocytes function in the exchange of nutrients and wastes with the blood. They also maintain normal bone structure by recycling the mineral salts in the bony matrix. Osteoclasts remove bone tissue by releasing lysosomal enzymes and acids that dissolve the bony matrix. Osteoblasts are bone cells that are responsible for bone formation.
Glossary
- appositional growth
- increase in the diameter of bones by the addition of bone tissue at the surface of bones
- bone remodeling
- replacement of old bone tissue by new bone tissue
- bone
- (also, osseous tissue) connective tissue that constitutes the endoskeleton
- calcification
- process of deposition of mineral salts in the collagen fiber matrix that crystallizes and hardens the tissue
- compact bone
- forms the hard external layer of all bones
- diaphysis
- central shaft of bone, contains bone marrow in a marrow cavity
- endochondral ossification
- process of bone development from hyaline cartilage
- epiphyseal plate
- region between the diaphysis and epiphysis that is responsible for the lengthwise growth of long bones
- epiphysis
- rounded end of bone, covered with articular cartilage and filled with red bone marrow, which produces blood cells
- flat bone
- thin and relatively broad bone found where extensive protection of organs is required or where broad surfaces of muscle attachment are required
- Haversian canal
- contains the bone’s blood vessels and nerve fibers
- intramembranous ossification
- process of bone development from fibrous membranes
- irregular bone
- bone with complex shapes; examples include vertebrae and hip bones
- lamella
- layer of compact tissue that surrounds a central canal called the Haversian canal
- long bone
- bone that is longer than wide, and has a shaft and two ends
- osseous tissue
- connective tissue that constitutes the endoskeleton
- ossification
- (also, osteogenesis) process of bone formation by osteoblasts
- osteoblast
- bone cell responsible for bone formation
- osteoclast
- large bone cells with up to 50 nuclei, responsible for bone remodeling
- osteocyte
- mature bone cells and the main cell in bone tissue
- osteon
- cylindrical structure aligned parallel to the long axis of the bone
- sesamoid bone
- small, flat bone shaped like a sesame seed; develops inside tendons
- short bone
- bone that has the same width and length, giving it a cube-like shape
- spongy bone tissue
- forms the inner layer of all bones
- suture bone
- small, flat, irregularly shaped bone that forms between the flat bones of the cranium
- trabeculae
- lamellae that are arranged as rods or plates | 4,306 | common-pile/pressbooks_filtered | https://opentextbc.ca/biology/chapter/19-2-bone/ | pressbooks | pressbooks-0000.json.gz:42086 | https://opentextbc.ca/biology/chapter/19-2-bone/ |
Og5yUb05Z_QiCjUv | Navigating Digital Media Literacy | Digital Story Maker
Now have students visit the MediaSmarts Digital Story Maker using the link in the Digital Story Maker student chapter. Explain that they are going to use this tool to make their three-segment digital stories.
The digital story maker can be accessed on any device that has an internet browser such as Chrome, Firefox, Safari and so on.
Students can make an account with either their names and email addesses, or just a usernames. If they use their email addresses, they will be sent a confirmation link to that address. They must click it to activate the account. If they ever forget your password, a recovery email will be sent to that address. If you want students to use this method, it is recommended that you have them set up accounts a day before you do this activity, so that class time is not used waiting for emails to arrive and accounts to be activated.
If students use just a username, they will be logged in right away. There is no way to recover a lost password if they use this method, so they should make sure to record their usernames and passwords.
This is particularly important if you plan to deliver the Second Draft lesson, in which students revise a digital story project they made earlier in the course.
Go through the steps of using the tool with students:
Creating a digital story
To start making your digital story, they will need to click or tap “Start Here”:
Next, go through the instructions. Point out to students that they have already done a lot of this while planning their stories and making their story tables.
Students should then give your stories a name and click or tap “Start”:
Adding segments
Next, students add the audio and image for each segment. For the audio, they can use the story maker to record your narration or upload narration they made previously, such as with their phones. They can also leave a segment silent by choosing “No audio”.
They can either upload an image for each segment or choose one from the gallery.
Note to students that it is only possible to use still images in the digital story maker. Explain that this is intended to keep things simple while they are learning the format.
For both the audio and images, if students are using imported files they will have to identify under what right they are using them. Some sources of royalty-free and copyright-cleared images include Pixabay, Pexels and the Internet Archive. You can use the Council of Ministers of Education’s Fair Dealing Decision tool to determine whether your students can use other online sources for this project. For a more thorough explanation of Fair Dealing and Creative Commons, see the lesson Remixing Media or the article Fair Dealing for Media Education.
Choosing music
Once students have made at least three segments, they can choose their music. There are a limited range of music options. Have students listen to the options and click or tap the circle next to the title of the one they want:
Rendering and downloading
Once students have made at least three segments and chosen their music, they can render their videos. That turns the project into a video format that can be played in other apps and on other devices. To do that, they click or tap Render video.
Once the video is rendered, students will be able to download it onto their device by clicking or tapping Download video:
Use the Assessment rubric for digital story assignment if you are delivering this as a separate unit, or use the assessment rubric for the specific unit into which you are integrating it.
If you like, you can have students share the videos they made with the class.
For each video, ask students:
- Was the story clear?
- Did they understand the video maker’s point of view and why the story is important to them?
- Did the images, narration and music work together to make them feel a certain way?
Rendering turns a project file into a format that can be downloaded and played by others. | 900 | common-pile/pressbooks_filtered | https://pressbooks.pub/navigatingdml/chapter/digital-story-maker-2/ | pressbooks | pressbooks-0000.json.gz:82484 | https://pressbooks.pub/navigatingdml/chapter/digital-story-maker-2/ |
X5XNpu_Hte-G-QWm | Mithradates of Parthia and Hyspaosines of Characene: a numismatic palimpsest, by Edward T. Newell. | With many plates, illustrations, maps and tables. Less than a dozen complete sets of the Jour- — nal remain on hand. Prices on application. —
NumIsMATIC NOTES AND MONOGRAPHS is devoted to essays and treatises on subjects relating to coins, paper money, medals and decorations, and is uniform with Hispanic Notes and Monographs published by the Hispanic Society of America, and with Indian Notes and Monographs issued by the Museum of the American Indian—Heye
By Epwarp T. NEWELL
Some fifteen years ago, in a rather typical parcel of ancient copper coins sent the writer from Baghdad, there were a number of unusual pieces bearing the head of the Parthian king, Mithradates II. These particular specimens, six in number, formed a group by themselves, distinguished from the remainder of the lot not only by their types but also by a peculiar reddish patina which they bore.. Apparently, they were a “‘find’’, ora portion of one. Other matters intervening, it was not until recently that a perusal of an article by Col.
A NUMIip ai
A. de la Fuye! brought a reminder of the forgotten parcel from Baghdad. Now, Col. de la I'uye discusses twenty-seven pieces similar to the ones described below, together with twenty-three of the autonomous coins of Seleucia on the Tigris. The specimens in our lot, as mentioned above, numbered six. Five belong to one denomination, and the sixth was evidently the half of the larger pieces. Their description is as follows :
The coins are poorly struck, apparently from loose dies. No two of the reverse dies are the same. Because of the rather weak striking and the interfering traces of an earlier type it is practically impossible to establish the identity of any two of the obverse dies.
With the exception of the brief description and ‘mention made by Col. Allotte de la Fuye the coins appear not to have been previously known.
Dela Fuye would assign them to Mithradates I, basing his attribution on the similarity which he finds between the portrait on these copper coins and the head which appears on certain well-known tetra-
A NUMISMADT EC
drachms and drachms? of that king. But here a serious difficulty arises. The silver coins in question bear the two dates [ OP or AOP which can have been reckoned according to the Seleucid era only. These silver coins, then, were certainly struck in 3abylonia by Mithradates I in 140/39 and 139/38 B.c., the two years which intervened between his defeat of Demetrius II and his own death. This assignment] has been followed by the latest authorities on the subject of the Parthian coinage and can hardly be seriously questioned. Our copper coins,'on the other hand, bear the date A?P which, following the Seleucid system of reckoning, would be 122-1 B.c. Col. de la Fuye refers A?P to the era of Alexander in Persia (330 B.c.), made known to us by a Chinese treatise3 on the life of Mohammed, itself probably a translation of an earlier Arabic or Persian document. This era is further known to us only from Albiruni’s Athar ul bakiya. According to Col. de la Fuye’s hypothesis, then, our copper coins must also have been struck in 140/39 B:C. ;
Peer Vier SH S T
Such a result, however, is hardly admissible. We should have appearing in the same year silver coins dated according to the Seleucid era, and copper coins dated according to an obscure Alexander era, known to us only from later Mohammedan sources. To make matters worse, both categories of coins were certainly struck in the same general district, for both the silver and the copper coins are characteristically Babylonian in fabric and style, and their usual find-spots would seem to support this assignment. Furthermore, on the remainder of their dated coin issues, the Parthians invariably employed the Seleucid era. And particularly in Pabylonia—where the mint of our bronze coins must have been located —the use of the Seleucid era under the Parthians is attested by numerous clay tablets bearing dates according to that era.4 There is, then, no other admissible postulate than that A?P is based on the Seleucid system of reckoning and that it represents the date 122-121 B.c. This date falls within the reign of Mithradates II who ascended
While admitting that the portrait on these bronze coins is very similar to that found on the Babylonian tetradrachms and drachms of Mithradates I, may this not be due to the fact that both heads face to the right, that their place of origin being the same, (Babylonia), their products should also be very similar, and that the features of Mithradates I are, taken as a whole, not so very dissimilar [rom those of his grandson, Mithradates II? As the usual issues of the latter are of somewhat different style and fabric, it results that at first sight the head on our bronze coins seems to vary slightly from that usually attributed to Mithradates II. If, however, we should carefully compare it with one of the earliest and finest of the latter’s silver issues (Plate II, 9) it will at once be seen that, feature by feature, the two portraits are not so very dissimilar after all. As the date borne by the copper coins would seem to make their attribution certain, the slight variation noticeable in the king’s features may safely be
fecal MPSES T
set down to the local Hellenic influence of the mint at which the coins were struck, and to the fact that they belong to the very first years of Mithradates II’s long reign.
The reverse type of the larger denomination (Nos. 1-5) is new for the issues of Mithradates II. It 1s, in fact, the earliest appearance of the Cornucopiae as a Parth1an type. Under the later kings this particular type was but seldom used. It occurs only once ona small bronze coin of Gotarzess and, in a double form, on a bronze coin of Phraates IV. On the other hand, the Bow in Case of the smaller denomination (No. 6) is a well known type of Mithradates II,7 as well as of other Parthian kings. The short inscription BASIAEQ= APZAKOY is unknown on the issues of Mithradates II who was more partial to increasingly grandiloquent titles, such as BASIAEQ= MELTAAOY AP2AKOY EITTIPANOYS; BASIAEQS
TOY KAI @IAEAAHN. — It will thus be seen that to the Parthian series as a whole, and to the issues of Mithradates II in particular, the coins here published are both new and interesting.
yet to be described.
A glance at the specimens themselves quickly reveals the important fact that one and all are overstrikes on some earlier issue. This is also true of the similar coins in Col. de la Fuye’s Collection. Traces of this overstriking may be seen in each and every case, but only on one or two specimens does enough of the earlier impression remain to allow us to determine what and whose the first issue must have been. On the reverses of Nos. 3 and 5 and on the obverse of No. 2 traces of a beardless, diademed, male head to right may just be distinguished (see Plate I], Nos. 1, 3, and 2 respectively). As all really individual features have been almost entirely obliterated by the restriking, it would be difficult, if not impossible, to determine without further aid whose portrait
Pate MP SES T
the head is intended to represent. On the obverse of No. 5 a few traces of the old reverse type can still be made out (Plate I; 5). These traces consist of the base with its usual ring, part of the shaft, and the left-hand flange of an ancient anchor set upright in the Seleucid manner. To the left of this object are traces of four error f = ILA. ;.: Also on the reverse of No. 4 (Plate II, 4) traces of —2TTA.. can still be made out.
Because of the anchor, one’s first thought, naturally enough, is that we have here to do with some earlier Seleucid issue. A careful search in the writer’s own collection, as well as through the exhaustive catalogues of the Paris, London, Petrograd and Glasgow collections, failed to produce a single Seleucid coin whose types quite answer in their details to the traces at our disposal. The nearest approach is a copper coin of Demetrius II (Paris Nos. 935-8, Pl. XIX,7; London No. 25, Pl. XVIII, 7) a specimen of which from the writer’s collection is reproduced on Plate II, No. 8. However, it is at once
evident that this cannot be the original coin on which the Parthian overstrikes have been placed. The flan does not possess a bevelled edge. In its essential outlines the portrait of Demetrius II is quite at variance with what remains of the earlier head on our coins. Finally, the three letters which happen to be fully preserved, — = TT A — — — —, do not occur in this order on the Seleucid coin whose inscription reads either BAZIAEQS AHMHT— PIOY NIKATOPO? or BAZSIAEOS
series.
Turning now to the smallest of our coins, No. 6, while the actual reverse design of the original piece has been effectually obliterated, it is a most fortunate chance that still preserves for us some six letters of the inscription. With the hint furnished us by Nos. 4 and 5, the letters Y 21T AO &- - -can now readily be made out. In other words, the coins re-used as blanks by the Parthian mint-master turn
out to be specimens of some unknown bronze issue of the first king of Characene, Hyspaosines son of Sagdodonakos.
The coinages of the kings of Characene, an important district comprising the delta of the Tigris and Euphrates rivers, have been exhaustively studied by Waddingtom) babelon’?, and Mr.. Hill. These writers have shown that the issues commenced with Hyspaosines, known to have founded the chief city, Xapa& “Torraoatvov (Spasinou Charax). His period has been established by his known coins which bear the date HITP. This would represent 125-4 B.c. if, as has been assumed, the Seleucid era was the one used. Mr. Hill? says that while “‘there is no absolutely certain evidence that the Seleucid era is that which is employed on the Characenian coins”’ this is nevertheless extremely probable. Of this our coins now furnish us with the necessary confirmation. Hyspaosines’ copper coins must have been issued previous to 122-1 B.c., for the Parthian type superimposed upon them is dated A?P, and we know that the
Parthians reckoned their dates according to the Seleucid era. Judging by the traces (in themselves sharp enough) of the old types, still to be seen on our coins, these could not have been in circulation so very long before they were put to use as blanks in the Parthian mint. The only date so far found on Hyspaosines’ coins (his two tetradrachms) is HTTP which, if we reckon according to the Seleucid era, would be 125-124 B.C., or just three years previous to the date borne by our Parthian overstrike. Everything points, therefore, to the correctness of the belief that the Seleucid era was used for dating the Characenian coinage.
What the particular occasion could have been which caused types of Mithradates II of Parthia to be struck upon those of Hyspaosines of Charax, we do not know. It may merely be that such Characenian coins as chanced to come by trade the short distance upstream to the great city of Seleucia on the Tigris, were employed as coin blanks by the Parthian mint located in that city. However, as yet we
have no means of being certain that these coins were really re-coined in Seleucia. It should be noticed that every one of the specimens at our disposal is thus overstruck,'3 and itis hardly probable that such an important mint should have been forced to depend for its coin blanks solely upon such Characenian coins as happened to reach it.
Analogy with later Parthian overstrikes™ —almost invariably the result of some military success — would seem to suggest that in the present instance, too, the overstriking might have been the direct consequence of a victory gained by Mithradates over the king of Characene, whereby a large number of the latter’s coins fell into his hands. But our lamentably fragmentary history is entirely silent with regard to any campaign conducted by Mithradates against Hyspaosines. We only know that at the time of his accession, Mithradates, by his great ability, saved the Parthian kingdom from disintegration. He checked the advance of the Scythians, and modern historians have surmised that at this time
A NUM Sata
he also, put down an attempt made by Himerus,viceroy's of Babylon, tomake himselfking. Thelatter’s onlyknown dated coin was struck in OTTP (124-123 B.c.)'© and gives to Himerus the title of Nuandopos. As one of our few historical notices of this shadowy ruler actually states that he made war upon Messene (a province of Characene and often synonymous for it) perhaps the title has a direct reference to the outcome of that campaign. Possibly Justin’s general statement (xlii. 2): ‘He (Mithradates) carried on many wars, with great bravery, against his neighbors, and added many provinces to the Parthian kingdom,’’ may be regarded as implying a campaign against Characene. If so, however, the suggestion must not be taken too literally, at least as far as regards Characene. That province actually remained more or less independent of Parthian rule throughout the reign of Mithradates II, as the extant coins of its kings sufficiently prove. Nothing would hinder us however from supposing that Mithradates might have been victorious, and
to his kingdom.
From the foregoing it may be surmised, either that Mithradates, after suppressing Himerus, successfully carried on the operations commenced by the latter against Characene, or that in Himerus’ treasury was found a lot of Characenian money captured from Hyspaosines but which had not yet been re-minted by Himerus.!7 These coins, if our conjecture —and it is merely a conjecture —be correct, Mithradates, in the year 122-121 B.C., put to his own use by overstriking with his types.
The only coins of Hyspaosines hitherto known are two silver tetradrachms, the one in the Berlin collection, the other in Paris. That Hyspaosines should also have struck a series of copper coins might have been surmised, and for this supposition we now have evidence. The types of the larger of the two denominations.are, obverse : diademed, beardless head of Hyspaosines to r., exactly as on his silver coins; reverse: Seleucid anchor upright
A NUM DSS fue
between BASIAEQS (probably) and YSTTAOSINOY. A proposed restoration of this piece is given, Plate II, no. 7. Of the smaller denomination the obverse type only is preserved. It consists of a similar portrait of Hyspaosines tor. The reverse type, with the exception of the king’s name, has been completely obliterated by the Parthian overstrike. It is to be hoped that some future find will give us both coins with types intact. In the meanwhile we must needs remain content with what the vicissitudes of time, the expedient found necessary by the Parthian mint master, and the hasty or careless procedure of his workmen have preserved for us.
able to inspect these coins in Col. de la Fuye’s collection. All show signs of overstriking — though unfortunately none show sufficient
Diodorus, xxxiv, 21, actually calls him ‘‘king’’, 6 Tov IIdpOwy Baoire’s. The coins would seem to bear him out in this (B. MM; Car Parthia, p. 23, Nos. 1, 2, and note 2). See also the writer’s ‘‘A Parthian MHoard,’’ in Num. Chron., 1924.
silver money are known, as yet not a single bronze coin of his has come to light. The copper specimen published by Petrowicz, Plate xxv, 4, is more likely to be a coin of Phraates II (= B. M, Gat. Parthia) Pieineo)}
| 3,438 | common-pile/pre_1929_books_filtered | mithradatesofpar00newe | public_library | public_library_1929_dolma-0022.json.gz:4383 | https://archive.org/download/mithradatesofpar00newe/mithradatesofpar00newe_djvu.txt |
11Nmu2tZsD3PE4J- | 8.16: Links to Primary Sources | 8.16: Links to Primary Sources
Ancient Accounts of Arabia 430 BCE – 550 CE
legacy.fordham.edu/halsall/a...nt/arabia1.asp
Ibn Ishaq (d. c. 773 CE): Selections from the Life of Muhammad
legacy.fordham.edu/halsall/s...mmadi-sira.asp
The Prophet Muhammad: Last Sermon
legacy.fordham.edu/halsall/s...uhm-sermon.asp
Muhammad Speaks of Allah
www.mircea-eliade.com/from-pr...o-zen/040.html
Muhammad’s Call
www.mircea-eliade.com/from-pr...o-zen/231.html
Muhammad is the Messenger of God
www.mircea-eliade.com/from-pr...o-zen/232.html
Muhammad Proclaims the Prescriptions of Islam
www.mircea-eliade.com/from-pr...o-zen/122.html
The Sunnah, (traditions of the Prophet Muhammad), excerpts
legacy.fordham.edu/halsall/s...nnah-horne.asp
Abu Hamid al-Ghazali (1058 – 1111 CE): The Remembrance of Death and the Afterlife
legacy.fordham.edu/halsall/s.../alghazali.asp
The Battle of Badr, 624 CE
http://web.archive.org/web/199801191...m/battleof.htm
Al-Baladhuri: The Battle of The Yarmuk (636 CE) and After
legacy.fordham.edu/halsall/source/yarmuk.asp
Accounts of the Arab Conquest of Egypt, 642 CE
legacy.fordham.edu/halsall/s...gypt-conq2.asp
Yakut: Baghdad under the Abbasids, c. 1000 CE
legacy.fordham.edu/halsall/s...000baghdad.asp
Abul Hasan Ali Al-Masu’di (Masoudi) (c. 895? – 957 CE): The Book of Golden Meadows, c. 940 CE
legacy.fordham.edu/halsall/source/masoudi.asp
The Seven Voyages of Sinbad the Sailor story from the Thousand and One Nights
http://www.sacred-texts.com/neu/lang1k1/tale15.htm
Ibn Rushd (Averroës) (1126 – 1198 CE): Religion & Philosophy, c. 1190 CE.
legacy.fordham.edu/halsall/s...90averroes.asp
Firdausi: The Epic of Kings, c. 1000 CE
http://classics.mit.edu/Ferdowsi/kings.html
Sa’di (1184 – 1292 CE): Gulistan, 1258 CE | 236 | common-pile/libretexts_filtered | https://human.libretexts.org/Bookshelves/History/World_History/Book%3A_World_History_-_Cultures_States_and_Societies_to_1500_(Berger_et_al.)/08%3A_Islam_to_the_Mamluks/8.16%3A_Links_to_Primary_Sources | libretexts | libretexts-0000.json.gz:28829 | https://human.libretexts.org/Bookshelves/History/World_History/Book%3A_World_History_-_Cultures_States_and_Societies_to_1500_(Berger_et_al.)/08%3A_Islam_to_the_Mamluks/8.16%3A_Links_to_Primary_Sources |
_1UzfbkSFR68YBAl | Abnormal Psychology | 218 Introduction
A rudimentary knowledge of the different substances and their unique psychoactive effect is necessary in order to understand and treat substance use disorders because treating alcohol abuse is different from treating someone who has been abusing LSD or methamphetamines. In order to be effective, treatment must not only the physiological effects of the substance, but most also extend to the subjective psychological experience of the drug, the culture around the drug, the social views on the drug, the normal course of withdrawal, and finally, separation from use of the drug.
Underlying or co occurring emotional disorders must also be assessed since these disorders can mimic or exacerbate the effects of a mental disorder. Knowing the behavioral and mood altering effects of substances then is also essential for optimal assessment and treatment.
Substance abuse is not only a problem for the individual, but also leads to social and ethical problems for the society in which it occurs.
Finally, having an objective knowledge of drugs can help the treating professional understand when use of a substance is life threatening and should be referred for in patient and more intensive treatment. | 247 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/herkimerabnormalpsych/chapter/introduction/ | pressbooks | pressbooks-0000.json.gz:36837 | https://library.achievingthedream.org/herkimerabnormalpsych/chapter/introduction/ |
uPjUer-Vn9xJaMx0 | 12: Rings, Moons, and Pluto | 12: Rings, Moons, and Pluto
“Our imaginations always fall short of anticipating the beauty we find in nature.” —Geologist Laurence Soderblom, discussing the 1989 Voyager encounter with Neptune’s moons
All four giant planets are accompanied by moons that orbit about them like planets in a miniature solar system. Nearly 200 moons are known in the outer solar system—too many to name individually or discuss in any detail. Astronomers anticipate that additional small moons await future discovery. We have also discovered a fascinating variety of rings around each of the jovian planets.
Before the Voyager missions, even the largest of the outer-planet moons were mere points of light in our telescopes. Then, in less than a decade, we had close-up images, and these moons became individual worlds for us, each with unique features and peculiarities. The Galileo mission added greatly to our knowledge of the moons of Jupiter, and the Cassini mission has done the same for the Saturn system. In 2015, the NASA New Horizons spacecraft completed the initial exploration of the “classical” planets in the solar system with its flyby of Pluto and its moons. We include Pluto here because in some ways it resembles some of the larger moons in the outer solar system. Each new spacecraft mission has revealed many surprises, as the objects in the outer solar system are much more varied and geologically active than scientists had anticipated.
-
- 12.1: Ring and Moon Systems Introduced
- The four jovian planets are accompanied by impressive systems of moons and rings. Nearly 200 moons have been discovered in the outer solar system. Of the four ring systems, Saturn’s is the largest and is composed primarily of water ice; in contrast, Uranus and Neptune have narrow rings of dark material, and Jupiter has a tenuous ring of dust.
-
- 12.2: The Gailean Moons of Jupiter
- Jupiter’s largest moons are Ganymede and Callisto, both low-density objects that are composed of more than half water ice. Callisto has an ancient cratered surface, while Ganymede shows evidence of extensive tectonic and volcanic activity, persisting until perhaps a billion years ago. Io and Europa are denser and smaller, each about the size of our Moon. Io is the most volcanically active object in the solar system.
-
- 12.3: Titan and Triton
- Saturn’s moon Titan has an atmosphere that is thicker than that of Earth. There are lakes and rivers of liquid hydrocarbons, and evidence of a cycle of evaporation, condensation, and return to the surface that is similar to the water cycle on Earth (but with liquid methane and ethane). The Cassini-Huygens lander set down on Titan and showed a scene with boulders, made of water ice, frozen harder than rock. Neptune’s cold moon Triton has a very thin atmosphere and nitrogen gas geysers.
-
- 12.4: Pluto and Charon
- Pluto and Charon have been revealed by the New Horizons spacecraft to be two of the most fascinating objects in the outer solar system. Pluto is small (a dwarf planet) but also surprisingly active, with contrasting areas of dark cratered terrain, light-colored basins of nitrogen ice, and mountains of frozen water that may be floating in the nitrogen ice. Even Pluto’s largest moon Charon shows evidence of geological activity. Both Pluto and Charon turn out to be far more dynamic.
-
- 12.5: Planetary Rings
- Rings are composed of vast numbers of individual particles orbiting so close to a planet that its gravitational forces could have broken larger pieces apart or kept small pieces from gathering together. Saturn’s rings are broad, flat, and nearly continuous, except for a handful of gaps. The particles are mostly water ice, with typical dimensions of a few centimeters. Enceladus is today erupting geysers of water to maintain the tenuous E Ring, which is composed of very small ice crystals.
Thumbnail: This montage, assembled from individual Galileo and Voyager images, shows a “family portrait” of Jupiter (with its giant red spot) and its four large moons. From top to bottom, we see Io, Europa, Ganymede, and Callisto. The colors are exaggerated by image processing to emphasize contrasts. (credit: modification of work by NASA). | 900 | common-pile/libretexts_filtered | https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/12%3A_Rings_Moons_and_Pluto | libretexts | libretexts-0000.json.gz:44949 | https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/12%3A_Rings_Moons_and_Pluto |
4O6c1vHNmOG9Dcnw | 9.9: Preparing to Use a Database- What Do You Need to Find? | 9.9: Preparing to Use a Database- What Do You Need to Find?
One of the main tasks that you will do within library databases is find articles, often scholarly journal articles. Fortunately, many library databases include filters that limit your results to just scholarly journal articles. This is especially helpful when using the big aggregator search tools from EBSCO, ProQuest, and Gale. But there are often other considerations to take into account when finding resources. As a reminder, always check your assignment requirements and ask yourself these questions:
- How many resources am I required to find?
- What types of resources am I required to find?
- Are there any types of resources that I am not allowed to use?
- Is there a requirement related to the publication date of the resources?
- Are there any other requirements that might be helpful to remember (due dates, citation styles, etc.)?
Let’s look at our scenario for this chapter to answer these questions:
Your English professor has assigned the class an argumentative essay. Your assigned topic for the essay is artificial intelligence. You are required to find evidence to support your argument from scholarly journals, magazines, newspapers, and books.You have to cite at least seven sources, at least one of each type, and you also have the option to use a video for one of your sources. Your professor states that she doesn’t want you to use websites for your essay; you must use library databases and format your citations according to MLA.
According to the Scenario, we can answer the guiding questions as follows:
- Seven resources.
- At least one scholarly journal article, one magazine article, one newspaper article, and one book. That’s only four out of the seven. You must find more of those resources to equal seven, and you can also use videos. All resources must come from library databases.
- You can’t use websites.
- No publication date restrictions were provided.
- MLA citation style must be used.
Having this information outlined for yourself will help you stay focused as you search through the library databases. After identifying some keywords to seek resources related to your topic, you can then use filters to limit your results to specific resource types (depending on the library database you are using). You should also be able to limit to a publication date when necessary. | 514 | common-pile/libretexts_filtered | https://human.libretexts.org/Bookshelves/Research_and_Information_Literacy/Introduction_to_College_Research_(Butler_Sargent_and_Smith)/09%3A_Using_Library_Databases/9.09%3A_Preparing_to_Use_a_Database-_What_Do_You_Need_to_Find | libretexts | libretexts-0000.json.gz:33455 | https://human.libretexts.org/Bookshelves/Research_and_Information_Literacy/Introduction_to_College_Research_(Butler_Sargent_and_Smith)/09%3A_Using_Library_Databases/9.09%3A_Preparing_to_Use_a_Database-_What_Do_You_Need_to_Find |
W1Gy-hn_TFkAwVhk | Mathematics for collegiate students of agriculture and general science. | PREFACE
This book is designed as a text in freshman mathematics for students specializing in agriculture, biology, chemistry, and physics, in colleges and in technical schools.
The selection of topics has been determined by the definite needs of these students. An attempt has been made to treat these topics and to select material for illustration so as to put in evidence their close and practical relations with everyday life, both in and out of college. It is certain that the interest of the student can be aroused and sustained in this way. We believe also that he can be trained to understand and to solve those mathematical problems which will confront him in the subsequent years of his college work and in after-life, without losing anything in orderly arrangement or in clear and accurate logical thinking.
Reference to the table of contents will indicate the scope and proportions of the material presented and something of the means employed in relating the material to the vital interests of the student and of correlating it to his experience and his intellectual attainments. Many of the chapter subjects and paragraph headings are traditional. Nothing has been introduced merely for novelty. Since this course is to constitute the entire mathematical equipment of some students, some chapters have been inserted which have seldom been available to freshmen; for example, the chapters on annuities, averages, and correlation, and the exposition of Mendel's law in the chapter on the binomial expansion.
Particular attention has been given to the illustrative examples and figures, and to the grading of the problems in the lists. The exercises constitute about one fifth of the text and contain
a wealth of material. They include much data taken from agricultural and other experiments, carefully selected to stimulate thinking and to show the application of general principles to problems which actually arise in real life, and in the solution of which ordinary men and women are vitally interested.
The book is intended for a course of three hours a week for one year, but it can be shortened to a half-year course. The chapters on statics, small errors, land surveying, annuities, compound interest law, and as many as is desired at the end, can be omitted without breaking the continuity of the course.
The first two chapters are more than a mere review. This matter is so presented as to give the student a new point of view. The treatment will show the significance and importance of certain fundamental relations among the concepts and processes of arithmetic and algebra which the student may have used somewhat mechanically .in secondary school work. Well prepared students can read these chapters rather rapidly, however.
The four place mathematical tables printed at the end of the text have been selected and arranged for practical use as the result of long experience and actual use in computing, and are adapted to the requirements of the examples and exercises in the book.
The first edition of this book contained problems, formulas and other matter taken from a large number of sources. Those passages that were directly from other books have now been entirely rewritten ; but the book remains indebted to a number of others, notably SKINNER, Mathematical Theory of Investment, and DAVENPORT, Principles of Breeding. Other references occur throughout the text.
INTRODUCTION
1. Uses of Mathematics. The applications of mathematics are chiefly to determine the magnitude of some quantity such as length, angle, area, volume, mass, weight, value, speed, etc., from its relations to other quantities whose magnitudes are known, or to determine what magnitude of some such quantity will be required in order to have certain prescribed relations to other known quantities.
2. Measurement. To measure a quantity is to find its ratio to a conveniently chosen unit of the same kind. This number is called the numerical measure of the quantity measured.
• The expression of every measured quantity consists of two components: a number (the numerical measure), and a name (that of the unit employed). For example, we write: 10 inches, 27 acres, 231 cubic inches, 16 ounces, 22 feet per second.
3. Arithmetic and Algebra. In arithmetic we study the rules of reckoning with positive rational numbers. In algebra negative, irrational, and imaginary numbers are introduced, letters are used to represent classes of numbers, and the rules of reckoning are extended and generalized. Algebra differs from arithmetic also in making use of equations for the solution of problems requiring the discovery of numbers which shall satisfy certain prescribed conditions.
4. Positive Numbers. The natural numbers 1, 2, 3, 4, etc., are the foundation on which the whole structure of mathematics is built. They are also called whole numbers, or positive integers. Together with the fractions, of which 1/2, 5/3, .9, 2.31, are examples, they form the class of positive rational numbers.
whose numerator and denominator are whole numbers.
Two quantities of the same kind are said to be commensurable when there is a unit in terms of which each has for numerical measure a whole number. Consequently, their ratio is a rational number. If two quantities are not commensurable, they are said to be incommensurable.
The ratio of two quantities which are incommensurable, such as the side and the diagonal of a square, or the diameter and the circumference of a circle, is an irrational number.
No irrational number can be expressed as a fraction whose numerator and denominator are whole numbers. However, it is always possible to find two rational numbers, one less and the other greater than a given irrational number, whose difference is as small as we please. For example,
and the difference between the first and the last of these numbers is only .000001. Two such rational numbers whose difference is still less can easily be found. In all practical applications, one of these rational numbers is used as an approximation for the irrational number. Thus, we may find the length of the circumference of a circle approximately by multiplying its diameter by 3f. If a closer approximation is needed, the value 3.1416 is often used.
5. Negative Numbers. Zero. To every positive real number r, there corresponds a negative real number — r, called negative r. The negatives of the natural numbers are called negative integers. The real number zero separates the negative numbers from the positive numbers. It is neither positive nor negative and corresponds to itself.
6. The Four Fundamental Operations. The direct operations of addition and multiplication of real numbers are so defined that they are always possible, and so that the result in each case is a unique real number. These operations are subject to the rules of signs and to the following fundamental laws of algebra.
The indirect operations of subtraction and division of real numbers are always possible, division by zero excepted,* and the result is a unique real number.
7. Involution and Evolution. Involution, or raising to powers, is always possible, and the result is unique when the base is any real number provided the exponent is a positive integer.
* Division by zero is excluded because, in general, it is impossible, and when possible it is trivial. Thus there is no real number which will satisfy the equation 0 -x = o 4= 0, and every real number satisfies the equation 0 -x = 0.
Evolution, or extraction of roots,* is not always possible. Even when possible, it is not always unique. In particular, the square of every real number is a positive real number. Hence no negative number can have a real square root. On the other hand, every positive real number, a, has two real square roots: a positive one, which is denoted by the symbol •^a; and a negative one, which is denoted by — Va. In fact, every positive real number has exactly two real nth roots of every even index n, denoted by Va and — "N/o, respectively. Every real number, r, has a unique real nth root of every odd index n, denoted by Vr; it is positive when r is positive, and negative when r is negative.
8. Rational Exponents. Involution is extended to fractional exponents as follows. If a is a positive real number, and if m and n are natural numbers, we define amln by the equation
A consequence of this definition is the rule: A factor may be moved from the numerator to the denominator of a fraction, or vice versa, on changing the sign of its exponent. For example,
10. Laws of Exponents. The following five laws are useful for the reduction of exponential and radical expressions to simpler forms. They are valid, (1) when the bases are any real numbers whatever, provided the exponents are integers or zero, and (2) when the exponents are any real numbers whatever, provided the bases are positive.
Similarly, each of the other laws can be proved when the exponents are positive integers. When the exponents are negative, we make use of the definition of § 9. If they are positive fractions we make use of the following lemma: // a and b are real numbers of like sign, and if an = bn, where n is a positive integer, then a = b.
By observing the coefficients and the exponents of x and of y in the various terms, we observe the law by which these results can be written down without the work of multiplying them out.
(2) The exponent of x in the first term is n and it decreases by 1 in each succeeding term; the exponent of y in the second term is 1 and it increases by 1 in each succeeding term.
(3) The first coefficient is 1; the second is n; the coefficient of any term after the second may be found from the preceding term by multiplying the coefficient by the exponent of x and dividing by a number 1 greater than the exponent of y.
These three statements constitute the binomial theorem, which will be proved in § 208, Chapter XVI, for all values of x and y no matter how large the positive integer n may be. The coefficients which appear in these expansions are called binomial coefficients. For example, the numbers
12. Use of Equations. As indicated before, the chief advantage of algebra over arithmetic in solving problems lies in the method of attack. The algebraic method is to translate the problem into an equation and then to solve the equation by general methods.
13. Definition of an Equation. An equation is a statement of the equality of two expressions. Each of the expressions may contain letters and figures called knowns, representing numbers supposed to be given or known; letters called unknowns, representing numbers to be found; and symbols of operation and combination, such as +, — , etc.
The expression on the left of the equality sign is called the left member, or the left side, of the equation. The other is called the right member, or right side.
14. Substitution. It is often necessary to substitute for the unknowns in an expression such as one of the members of the above equations, certain definite numbers, called values of the unknowns. The result of such substitution is, in general, to reduce the expression to a single number.
y, each member reduces to 1.
15. Solution of an Equation. Any set of values of the unknowns which reduces each of the two members of an equation to the same number is said to satisfy the equation, and to be a solution of the equation. A solution of an equation in one unknown is also called a root of the equation.
The final test to determine whether a set of values of the unknowns in an equation is a solution or not, is to substitute these values for the unknowns and see whether the equation is satisfied or not.
For example, x = 20 is a solution of equation (1), § 13. The value x = 10 does not satisfy it. Again, z = |, x = 1, x = — 2, are three solutions of (2). Every real number is a solution of (3). The value x = 2 is a solution of (4). The value x = 15 is a solution of (5). The values x = 2, y = — 1 constitute a solution of (6). Every pair of real numbers constitutes a solution of (7).
16. Identities. An equation which is satisfied by all values of the unknowns (excepting those values if there are any for which either member is not defined) is called an identity. An
neither side is defined.
The distinction in point of view between identities and conditional equations is fundamental. To show that an equation is not an identity, we need only find a single set of values of the unknown quantities for which both sides are defined, and for which the equation is not true.
17. Equivalent Equations. Two equations are said to be equivalent when every solution of the first is a solution of the second and conversely, every solution of the second is a solution of the first.
If all the terms of an equation be transposed to the left side (so that the right member is zero), if the left member be factored, and if each of the factors be equated to zero, then the solutions of the separate equations so formed are all solutions of the original equation, and it has no others.
The following changes in an equation lead to a new equation which is satisfied by every solution of the given equation, but which generally has other solutions also.
same positive integral power.
Since the new equation is not, in general, equivalent to the given equation, it is necessary to test all results by substituting them in the given equation in its original form.
which results from squaring and transposition in the former; but they are not equivalent; the latter equation has the two solutions x = 2, x = 7, while the former has only one, x = 7.
19. Simultaneous Equations. When a common solution of two or more equations is sought, the equations are said to be simultaneous. For example, each of the equations
has an infinite number of solutions: (0, — 2), (2, 1), (4, 4), (G, 7), etc., satisfy (8), and (1, - 1), (2, 1), (3, 3), (4, 5), etc., satisfy (9). But (2, 1) is the only common solution.
By a solution of a set of equations is meant a common solution of all the equations of the set, regarded as simultaneous equations. Thus, the set of equations (8) and (9) has a unique solution, namely, x = 2, y = 1.
each set is satisfied by all of the solutions of the other set.
If each of two or more equations from a set of simultaneous equations be multiplied through by any constant, or by any expression containing unknowns,* and if the resulting equations
be added or multiplied together, the new equation will be satisfied by all the (common) solutions of the given set. EXAMPLE. If in the set of simultaneous equations,
20. Elimination. By a proper choice of multipliers we can use the above principle to secure a new equation lacking a certain term, or certain terms, which occur in the given set of equations. The missing terms are said to have been eliminated and this process is called elimination by addition.
by multiplying by — 2 and + 5, respectively, and adding. The result is 13x = 26. We conclude that if the given equations have a common solution, it is x = 2, and we verify that this is a solution of each. If we eliminate x2 from the equations,
When it is possible to solve one of a set of simultaneous equations for one of the unknowns, we can eliminate this unknown by substituting the value thus found in the other equations of the set. This is called elimination by substitution.
If we can solve each of two simultaneous equations for the same unknown, this unknown will be eliminated by equating these two values to each other. This is called elimination by comparison.
21. Linear Equations. An equation of the first degree in the unknown quantities is called a linear equation. A set of linear simultaneous equations can be solved, if they have a solution, by successively eliminating the unknowns until a single equation in one unknown is obtained.
which is equivalent to y = — 4. Substituting — 4 f or y in either of the given equations, we fird x = — 3. Finally, we verify that x = — 3, y = — 4, is a solution of the given set.
Ans. 8 and 4 pints.
10. Two given mixtures contain respectively p% and q% of a certain ingredient. Show that if x units of the first be combined with y units of the second so that the resulting mixture contains r% of this ingredient, then x:y = r — p:q — r.
10. Assume that gravel has 45% voids and sand 33%, and that 4 bags of cement make 3.8 cu. ft., how much cement, sand, and gravel are necessary to make 1 cu. yd. of concrete?
A polynomial, in x for example, is a sum of terms each containing a positive integral power of x multiplied by a coefficient independent of x, and usually also an absolute term.
To each value of x, which is called the variable, there corresponds a unique value of the polynomial. For example, the values of x2 — 3x + 2 which correspond to x = 0, x = 1, x = \, are 2, 0, f .
The degree of any term in a polynomial is the exponent of the variable in that term. The degree of a polynomial is the degree of the term of highest degree in it. Polynomials are usually arranged according to the degrees of the terms and it is sometimes convenient to supply with zero coefficients missing terms of degree lower than the degree of the polynomial; thus
A sharp distinction is to be made between the coefficients and the exponents in a polynomial. The coefficients are very general: they may be any real numbers whatever, natural numbers, rational or irrational numbers, positive, negative, or zero. On the other hand the exponents are very special: they must be positive integers. Thus while the expressions
are not.
23. Polynomial of the nth Degree. A polynomial of degree n in x (n being any given natural number 1, 2, 3, • • •) can be reduced by merely rearranging its terms and adding the coefficients of like powers of x to the form
24. Linear Equations. An equation of the first degree, or a linear equation, in one unknown, x for example, is the result of equating to zero a polynomial of the first degree in x,
finding the solution is already known to the student.
25. Quadratic Equations. An equation of the second degree, or a quadratic equation, in x for example, is the result of equating to zero a polynomial of the second degree in x,
is a quadratic.
SOLUTION BY FACTORING. If the polynomial axz + bx + c can be factored into two linear factors in x (i. e., polynomials of the first degree in x) the roots of the quadratic equation ax2 + bx + c =0 can be found by inspection.
EXAMPLE 1. Solve 6x2 + x = 15. Transpose all terms to the left side and factor. In order to do this we seek a pair of numbers whose product is 6 and another pair whose product is — 15 and such that the cross product is 1. The work may be put down as follows:
On equating the first factor to zero (mentally) and solving we get Xi = — 5/3 and similarly from the second factor xz = +3/2, and these are the two solutions of the given quadratic equation.
If there are fractional coefficients in a quadratic it is usually best to reduce it to an equivalent equation free from fractions by multiplying every term by the least common multiple of all the denominators. Thus in Example 2, we could multiply every term by 21 and obtain,
cannot readily be factored by inspection, the equation can be solved by transposing the absolute term c, completing the square of the terms in x and extracting the square roots of both sides.
To complete the square of ax2 + bx is to find a number d such that ax2 + bx + d is the square of a linear factor in x and it can always be done as follows: 1) extract the square root of the first term; 2) double this; 3) divide this into the second term; 4) square the quotient.
The computations are more easily made, if we multiply the given equation through by a number which will make the coefficient of x2 a perfect square. In the above example we should have to solve the equivalent equation,
27. Solution of a Quadratic by a Formula. By the process of completing the square, a formula for the roots of the general quadratic equation can be found as follows. Given the equation
This result may be used as a formula for the solution of any quadratic equation by substituting for a, 6, c, of this formula their values from the given equation.
37. If the radius of a circle be divided in extreme and mean ratio the greater part is the side of the regular inscribed decagon. What is the perimeter of the regular decagon inscribed in a circle 2 feet in diameter? Ans. 6.180
38. When a heavy body is thrown upward with an initial velocity v ft. per second, its distance from the earth's surface at the end of t seconds is given by the equation d — vt — 16<2. If a projectile is shot upward with a muzzle velocity of 1000 ft. per second, when will it be 15,600 ft. high? Ans. 30 and 32^ sec.
28. Equations in Quadratic Form. The terms of an equation which is not a quadratic in the unknown can sometimes be grouped so as to make it a quadratic in an expression containing the unknown. Thus, x4 — 13z2 + 36 = 0 is not a quadratic in x but it is a quadratic in x2] again if the terms of x* — 6x3 + 7x2 + Qx = 8 be grouped in the form
29. Imaginary Roots. . There are quadratics which are not satisfied by any real number. For example, z2 = — 4, x2 + 2x + 2 = 0. This is because the square of every real number (except 0) is positive. If we attempt to solve the equation x2 + 2x + 2 = 0 either by completing the square or by the formula we are led to the indicated square root of a negative number, and this is not a real number; thus
These, and other considerations have led to the invention of numbers whose squares are negative real numbers; they are called imaginary numbers. The imaginary unit is usually denoted by i. Hy definition, we have
The number r-i, where r is any real number is called a pure imaginary number; e. g., 2i, 5i, — 3i, -- %i, i V3, etc. The squares of pure imaginary numbers are negative real numbers; e. g., (2i)z = 22i2 = - 4; (- 3i)2 = (- 3)2i2 = - 9; (i VJF)2 = - 3.
Conversely, the square roots of negative real numbers are imaginary numbers; the square roots of — 4 are 2i and — 2i; i. e., V^l =_i VI" = 2i, - - V- 4 = - i VI" = - 2i; V^3
p is a real positive number.
Expressions of the form 2 + 5i, 1 — i, 3 — 2i, — I + i, etc., indicating the sum of a real and an imaginary number are called complex numbers. They may be added, subtracted, multiplied, and divided by the laws of algebra as though i were a real number and the results simplified by putting — 1 for i-,
can be separated into linear factors, its roots can be found by inspection. Therefore if we wish to make up a quadratic equation whose roots shall be two given numbers, r and s for example, we hare only to write
and multiply out. The factor a is arbitrary and may be chosen so as to clear the equation of fractions if desired; thus, to make an equation whose roots shall be f and — f , we write,
and this shows that no quadratic can have more than two roots. Some quadratics have only one root; for example 4z2 + 9 = 12x is satisfied only by x = 3/2.
one root, and conversely.
For, if 62 — 4oc = 0, then c = 62/4a and this is precisely the number necessary to complete the square of ox2 + bx. Also if 62 — 4oc = 0, the formula (13), § 27, gives not two but one root.
33. Kind of Roots. If a, b, and c, are real numbers and if 62 — 4ac > 0, then the quadratic equation ax* + bx + c = 0 has two real roots; but if 62 — 4oc < 0, the equation has two imaginary roots.
roots.
If a, b, and c, are rational numbers, then the roots of the equation ax2 + bx + c = 0 are rational if b2 — 4ac is a perfect square, i. e., the square of a rational number: in particular if a, b, and c, are integers and if b2 — 4ac is a perfect square the left member of the equation can be factored by inspection.
(9) 3x(x + 1) = (3 - x)(3 + x). (r) 3x2 = 13(x - 1). t(s) 0, + 2)(V - 2) = 2y - 7. (0 3fo + l)fo - 1) = 4y. (M) 60(3 - %) = 19(0 - I)2- (») 2/2 - 2yV3 + 7 = 0.
GRAPHIC REPRESENTATION
34. Graphic Methods. The methods studied in plane geometry for constructing various figures when certain of their dimensions and angles are known are used extensively in making designs for machines, plans for buildings and various other structures, and also for solving problems that require the determination of unknown dimensions, angles, areas, etc.
These methods often give the desired results with sufficient accuracy for practical purposes, and they are more direct and rapid than numerical computation. Of even greater importance however is their use in checking the results of calculations, since there are always possibilities of error even when great care is exercised. It should be emphasized that every practical calculation (i.e. one which is to be used in construction, or other actual work where time, material, and money will be wasted if the calculation is incorrect) should always be checked by some independent means.
are equal and their corresponding dimensions are proportional.
35. Drawing to Scale. When two plane figures are similar, each is said to be a scale drawing of the other. The smaller is said to be reduced or drawn to a smaller scale. For example, if a drawing be made of a floor plan of a house so that the angles in the drawing are equal to those in the house itself, and the dimensions of the drawing are -^ of those of the house, it is said to be drawn to a scale of ^ inch to one foot. From such a drawing the builder can read off on a scale divided into quarter inches the dimensions of the parts he is about to construct.
This method of drawing figures to scale, reading off their unknown angles on a protractor, and their unknown dimensions on a conveniently divided scale, furnishes a graphic solution of many problems and it has many practical applications.
EXAMPLE. The distance AB = 98 yards, Fig. 1, and the angles PAB = 51°, PBA = 63°, having been measured from one side of a river, the triangle can be drawn to scale and the width PR of the river can be read off on the scale, about 75 yards.
Ans. 1.3s
4. The pitch of a roof is the ratio of the height of the ridge above the plates to the distance between the plates. Find the length of the rafters and their inclination for a f pitch roof on a building 28 ft. wide.
5. Find the length of the corner rafters, and also of the middle rafter on each side of a square roof on a house 34 X 34 feet, the apex of the roof being 12 feet above the top floor. Find also their inclinations.
Ans. 32.6 ft.
7. To determine the horizontal distance between two points P and Q on the same level but separated by a hill, a point R is selected from which P and Q are visible. Then PR = 200 ft., QR = 223 ft., and angle PRQ = 62° are measured. Draw the figure and scale off PQ. Ans. 210.
9. Plot four points on a sheet of paper. Mark them A, B, C, D. Construct a point P one-half the way from A to B, a point Q onethird the way from P to C, and a point R one-fourth the way from Q to D. Mark the four given points in some other order and repeat the construction. What conclusion do you draw ?
FIG. 2
soon as we know its distance and sense from each of the two perpendicular lines X' X and Y'Y. These lines are taken first, and are drawn in any convenient position.
The distance from X' X (RP = b in the figure) is called the ordinate of the point P. The distance from Y'Y (SP = a in the figure) is the abscissa of P.
Abscissas measured to the right of Y'Y are positive, those to the left of Y'Y are negative. Ordinates measured above X' X are positive, those below negative.
The abscissa and ordinate taken together are called the coordinates of the point, and are denoted by the symbol (a, 6). In this symbol it is agreed that the number written first shall stand for the abscissa.
origin of coordinates.
The axes of coordinates divide the plane into four parts called quadrants. Figure 3 indicates the proper signs of the coordinates in the different quadrants.
FlG. 4
37. Plotting Points. To plot a point is to locate it with reference to a set of coordinate axes. The most convenient way to do this is to first count off from 0 along X'X a number of divisions equal to the abscissa, to the right or left according as the abscissa is positive or negative. Then from the point so determined count off a number of divisions equal to the ordinate, upward or downward according as the ordinate is positive or negative. The work of plotting is much simplified by the use of coordinate paper, or squared paper, which is made by ruling off the plane into equal squares, the sides being parallel to the axes. Thus, to plot the point (4, — 3), count off four divisions from 0 on the axis of X to the right, and then three divisions downward from the point so determined on a line parallel to the axis of Y, as in Fig. 4.
If we let both x and y take on every possible pair of real values, we have a point of the plane corresponding to each pair of values of (x, ?/). Conversely, to every point of the plane corresponds a pair of values of (x, y).
9. (a) What relation exists between the coordinates of any point of a line bisecting the angle between the positive directions of the two axes? (6) Between the positive direction of the y-axis and the negative direction of the x-axis?
10. What relation would exist between the coordinates of any point of the line in Ex. 9 (a), if it were raised four units parallel to itself? If it were lowered five units?
38. Statistical Data. The following table shows the rainfall in inches, as observed at the Agricultural Experiment Station at LaFayette, Indiana, by months for 1916, 1917, and the average for the past 30 years.
While it is possible by a study of this table to compare the rainfall month by month in the same year, or for the same month in the two years, or any month with the normal for that month,
these comparisons are more easily made and the facts are presented much more emphatically by the diagram shown in Fig. 5. This is made from the data of the table as follows. The 24 vertical lines represent the months of the two-year period. The altitudes of the horizontal lines represent inches of rainfall. The height (ordinate) of the point marked on any vertical line shows the rainfall for that month. The points are connected by lines to aid the eye in following the march of the rainfall. The full line represents the rainfall for 1916 and 1917, the dotted line the normal rainfall as shown by the experience of 30 years.
Rainfall is a discontinuous phenomenon. Moisture is not precipitated continuously, but intermittently. However, if we make a similar diagram showing the temperature at each hour of the day we might have inserted many other points. We
think of the change in temperature as a continuous phenomenon ; e.g. when the temperature rises from 42° at 8 A.M. to 51° at 9 A.M., we think of it as having passed through every intervening degree in that hour. Thus we can think of the points which represent the temperature on the diagram from instant to instant as lying thick on a continuous curved line. This curve is called the temperature curve.
In making a graph of a discontinuous function like rainfall, we connect the points with straight lines as in Fig. 5, but in case of a continuous function like temperature, a smooth curve which passes through all the plotted points is the best graphic representation of the function.
versity for as many years back as you can secure the data.
8. The following data give the Chicago price per bu. of No. 2 corn by months from Jan., 1903, to May, 1908. Plot the data using years as abscissas and price as ordinates.
9. Find from the graph that month in each year in which the highest price occurred. The lowest price. Find the difference for each year between the highest and lowest price for that year. Does there appear to be any relation between these prices and the period of harvest?
10. The following data gives the Chicago price of No. 2 oats by months from Jan., 1903 to May, 1908. Plot the data using years as abscissas and price as ordinates.
11. Handle the data in Ex. 10 as directed in Ex. 9.
12. A restaurant keeper finds that if he has G guests a day his total daily expenditure is E dollars and his total daily receipts are R dollars. The following numbers are averages obtained from the books:
For one curve use E as ordinates, for the other use R as ordinates.
Below what value of G does the business cease to be profitable? Connect the points (G, E) by a smooth curve. Continue this curve until it cuts the line (7 = 0. What is the meaning of the ordinate E for G = 0? Through what point ought the curve connecting the points (G, R) to pass? Ans. (0, 0).
respectively as ordinates.
15. The monthly wages in dollars of a man for each of his first 13 years of work was as follows: 28, 30, 37.50, 45, 60, 65, 90, 95, 95, 137, 162, 190, 210. Plot the curve showing the change. Estimate his salary for the fourteenth and fifteenth years. Can you be certain of his salaries for these years?
Plot the above data. Make two graphs. In each graph use deaths as ordinates; in one use months as abscissas, in the other use years. When is the ordinate smallest? largest? Does a small ordinate for the years 99-100 and 106-107 indicate a low death rate? Explain. Note the continuous decrease in the ordinate of the first curve.
17. Using the data below and on p. 46, plot a curve using years as abscissas and price of corn as ordinates. Do you notice any regularity in the number of years elapsing between successive high prices? successive low prices? Draw like graphs for the other crops listed?
18. Plot the prices for the yrs. 74,. 81, 87, 90, 94, 01, 08, 11, 1916. What do you observe from this curve as to the tendency in the high price of corn? Do you observe any tendency in the lowest prices of corn that is in the prices for the yrs. 72, 78, 84, 89, 96, 02, 06, 1910?
Potatoes.
Other Graphic Methods. The statistical data given in the preceding articles has been studied by means of curves or graphs drawn on rectangular cross-section paper. There arc other important methods of representing statistical data. Of these methods we will give names to three:
41. Double Bar Diagrams. In certain diagrams it is advantageous to have the bars extend in both directions from the base line as in the following figure which gives the distribution by age and sex of the total population for 1910.
966,000
43. Circular Diagrams. The following diagram shows the relative percentage of improved and unimproved land area in farms for the total land area of the U. S. 1850-1880-1910. (U. S. census report 1910.)
The circles indicate by the size of their sectors the relative ratio of lands improved and unimproved in farms to the total land area of the U. S. Note the rapid decrease in the area not in farms, also the increase in the proportion of improved to the unimproved. In 1910 less than 50% of the total area is in farms.
44. Different Shadings or Colors are sometimes used in maps to represent different statistical facts. The annexed chart gives the average value of farm land per acre in Delaware. The average for the state is $33.63.
EXERCISES
1. Draw a map of Connecticut showing the counties and mark to show the average value of farm land per acre. Average value for state is $33.03. Average value by counties is: Fairfield $75 to $100 per acre. New Haven and Hartford $25 to $50 per acre. Litchfield, Tolland, Windharn, Middlesex, and New London $10 to $25 per acre.
2. Draw a map, give legend, and mark to show per cent, of improved land in farms operated by tenants by states in 1910. Utah, less than 10 per cent. Wyoming, 10 to 20 per cent. Colorado and Missouri, 20 to 30 per cent. Kansas, Nebraska, and Iowa, 30 to 40 per cent. Illinois, 40 to 50 per cent.
45 . Distance between two Points. Let PI and P2 be the end points of a given segment in the plane. PI and P2 are given points, i.e., their coordinates (Xi, YI) and (^2, ^2) are given or known numbers.
and may be expressed in words thus : The distance between two points given by their rectangular coordinates is equal to the square root of the sum of the square of the difference of the abscissas and . the square of the difference of the ordinates.
46. Ratio of Division. Let PI and P2 be two fixed points on a line and P any third point. Then the point P is said to divide the segment PiP2 in the ratio
If the segments PiP and PiP2 have the same sense, the division ratio is positive and P and P2 lie on the same side of P\. If the segments PiP and PiP2 are oppositely directed, then the division ratio is negative and P and P2 are on opposite sides of PI. Thus, if the abscissas of PI and P* are 2 and 14, the abscissas of the points that divide PiP2 in the ratios 3, ^, f , - 1, - 1, - 2 are 6, 8, 10, - 4, - 10, - 22.
Draw PiQi, PQ, P2Q2 parallel to the y-axis, and PiRi, PR, P2R2 parallel to the z-axis. Then Q and R divide Q\Q2 and R\Ri, respectively, in the ratio X. Now as OQ\ = Xi, OQ2 = x2, OQ = x, it follows from (4) § 46 that
49. Locus of a Point in a Fixed Plane. If a point is forced to move so as to be always equidistant from two fixed points, we know that it must lie on the perpendicular bisector of the segment joining these points. If a point must be at a constant distance from a fixed point, it will lie on a circle. If a point must be always equidistant from a fixed point and a fixed line, it will lie on a certain curve, called a parabola, which we have not yet studied.
If x and y are the coordinates of a point P, the values of x and y change as P moves in the plane. For this reason they are called variables. If P is subject to a condition which forces it to lie on a certain curve, then x and y must satisfy a certain condition which can be expressed as an equation in x and y.
For example, if P is always equidistant from (1, 2) and (2, 1), then, for all positions of P, x — y = 0. If P is always equidistant from (0, 2) and the x-axis then x2 — 4y + 4 = 0. If P is always 3 units from the origin, then x2 + yz = 9.
Whenever a plane curve and an equation in x and y are so related that every point on the curve has coordinates which satisfy the equation, and conversely, every real solution of the equation furnishes coordinates of a point on the curve, then the equation is called the equation of the curve, and the curve is called the locus of the equation. This dual relation between equation and curve is the subject of study in Analytic Geometry.
50. Equation of a Locus. To find the equation of the locus of a point which moves in a plane according to some stated law, we proceed as follows: First, draw a pair of coordinate axes; and locate and denote by appropriate numbers or letters all fixed distances, including the coordinates of fixed points. Second, mark a point P with coordinates x and y, to represent the moving point ; express the conditions of the problem in terms of x, y, and the given constants ; and simplify the resulting equation.
equidistant from a fixed line and a fixed point.
First. We are free to choose the axes where we please. It is convenient to take the fixed line for the z-axis, and to take the y-axis through the fixed point. Then the coordinates of the fixed point may be called (0, a).
Second. The distance from P(x, y) to the fixed line is y, and its distance to the fixed point (0, a) is ^x2 + (y — a)2. Hence the condition expressed in the problem gives y = Vz2 -|- (y — a)2. This simplifies to
Third. It is easy to show, by reversing the above prqcess, that if x = h, y = k, is any solution of this equation, then the point Q (h, k) is equidistant from the re-axis and the point (0, a).
51. Locus of an Equation. In general a single equation in x and y has an infinite number of real solutions. Each of these solutions furnishes the coordinates of a point on the locus.
To find solutions and plot points on the curve, solve the equation, if possible, for y in terms of x, or vice versa. Determine and tabulate a convenient number of solutions by assigning values to x and computing the corresponding values of y. Using these for coordinates, plot the points which they represent and draw a smooth curve through the plotted points.
We note that each value of x gives two values of y, i.e. there are two
points on the curve having the same abscissa. We find also that values of x ^ 7 do not give real values of y and that the same is true for values of x ^ — 1.
When these points have been plotted and a curve drawn through them we have the locus as shown in Fig. 16a.
and extent of the locus can be
learned by a study of its equation. In the first example above, the equation is of the first degree in y. From this we infer that every value of x, without exception, gives exactly one value of y. Therefore every vertical line cuts the curve in one and only one point. As x increases beyond 2, y always increases, and the curve goes off beyond all limit in the first quadrant. The same is true in the second quadrant. On the other hand, the equation is of the second degree in x. When solved, it gives
hence every value of y greater than — 1 gives two real values of x but every value of y less than — 1 gives an imaginary value of x. Hence every horizontal line above y = — 1 cuts the curve in two points, but there are no points on the curve below y = — 1.
The equation of the second example, when solved for y as above, shows that values of x which make 1 + 6x — x2 < 0 give imaginary values for y. Hence there are no points on the curve to the left of the line x = 3 — V 10 = — 0.16, nor to the right of the line x = 3 + V 10 = 6.16, but every vertical line between these limits cuts the curve in two points.
hence there are no points below_the line y = 1 — VlO = — 2.16 nor above the line y = 1 + VlO = 4.16, but every horizontal line between these lines cuts the curve in two points.
an axis when the line AB is bisected at right angles by the axis.
If the points of a curve can be arranged in pairs which are symmetric with respect to an axis or a point, then the curve itself is said to be symmetric with respect to thai axis or point.
* The intercepts of a curve on the axis of x are the abscissas of the points of intersection of the curve and the z-axis. The intercepts on the j/-axis are the ordinates of the points of intersection of the curve and the j/-axis.
RULE III. // the equation of a locus remains unchanged in form when in it x and y are replaced by — x and — y, then the locus is symmetric with respect to the origin.
54. Points of Intersection. If two curves whose equations are given intersect, the coordinates of each point of intersection must satisfy both equations when substituted in them for x and y. In algebra it is shown that all values satisfying two equations in two unknowns may be found by regarding these equations as simultaneous in the unknowns and solving. Hence the rule to find the points of intersection of two curves whose equations are given.
55. Straight Line Parallel to an Axis. Suppose a point moves about on a piece of coordinate paper in such a way that it is always two units to the right of the axis of y. It would
evidently be on the line A B that is parallel to the y-axis and at a distance of two units to the right of OF. Every point of the line AB has an abscissa of two (x = 2), and every point whose abscissa is two lies on the line AB. For this reason we say that the equation
where a is any real number, represents a straight line parallel to the y-axis and at a distance a from it. Similarly, the equation y = b represents a line parallel to the z-axis.
56. Straight Line through the Origin. Suppose a point moves about on a piece of coordinate paper in such a way that its distance from the x-axis, represented by y, is always equal to m times its distance from the ?/-axis, represented by x. The equation of the locus of the point is
This is the equation of a straight line through the origin. The points of this line have the property that the ratio y/x of their coordinates is the same number m, wherever on this line the point is taken. Moreover for any point Q, not on this line, the ratio y/x must evidently be different from m. The number m is catted the slope of the line.
57. Proportional Quantities. Whenever two quantities y and x vary in such a manner that their ratio y/x is always constant, say m, they are said to be proportional. The constant m is called the factor of proportionality. Many instances occur
in the applied sciences of two quantities related in this manner. It is often said that one quantity varies as the other. Thus Hooke's law states that the elongation E of a stretched wire or spring varies as the tension t; that is, E = kt, where A; is a constant. For a given wire, when E was expressed in thousandths of an inch and t in pounds, the following relation was found:
two Points. Let the two given
points be PI(XI, yi), Pz(x2, y2). Let P(x, y) be any other point on the line joining PiP2. Draw PiRS parallel to the z-axis. Draw P\M\, P2M2, PM, parallel to the y-axis.
the straight line.
If both intercepts are given, say Z -intercept = a, ^/-intercept = b, we can find the equation of the line by means of the equation for a line through two given points. We have
Hence,
That is the slopes of any two non-vertical parallel lines are equal. 61. Perpendicular Lines. Consider two perpendicular lines LI and Z/2 intersecting at P\(x\, t/i). Let PI(XI + a, y\ + &) be a second point on L\\ then since the given lines are perpendicular, the point Qi(x\ — b, yi + a) lies on L2 as shown by construction in the figure. Then the slope of L\ is mi = b/a, by the definition of slope, § 58; and the slope of L2 is m2 =*
where A, B, C are constants, is called the general equation of the first degree in x and y because every equation of the first degree may be reduced to that form. For any values whatsoever of A, B, and C, provided A and B are not both zero, the general equation of the first degree represents a straight line.
(e) a = 3, 6 = 3. (/) a = 4, 6 = 2. (0) a = - 3, 6 = - 3. (h) a = 4, & = - 2. (t) a = - 3, b = 3. 0') a = 2, 6=4.
11. Write the equation of the line which shall pass through the intersection of 2y + 2x + 2 = 0 and 3y — x — 8 = 0, and having a slope = 4. Am. IQx — 4y + 51 =0.
14. Find the equations of the two straight lines passing through the point (2, 3), the one parallel, the other perpendicular to the line 4x - 3y = 6. Ans. 4x - 3y + 1 = 0, 3x + 4y - 18 = 0.
16. Passing through the point of intersection of 4x + y + 5 = 0 and 2x — 3y + 13 = 0, one parallel, the other perpendicular to the line through the two points (3, 1) and (— 1, — 2).
18. Find the equation of the straight line passing through the point of intersection of 2x + 5y — 4 = 0 and 2x — y + 1 =0 and perpendicular to the line 5x — Wy = 17. Ans. 6x + 3y = 2.
Find the rate of growth after 110 days.
[The rate of growth is the slope of the curve. The slope of a curve at a given point is defined to be the slope of the tangent line drawn to the curve at the given point. Draw the tangent with a ruler and with the aid of the eye.] Ans. 7/10 in. per day; 0.55 in. per day.
three numbers are involved. By omitting each number in turn there arise three different problems. If we omit the 100, we have the familiar question in involution:
ponential form. (2) is called the logarithmic form. Either of the statements (1) or (2), implies the other. The exponent in (1) is the logarithm in (2), a fact which may be emphasized by writing
For example, the following relations in exponential form: 32 = 9, 24 = 16, (1/2)3 = 1/8, a" = x, are written respectively in the logarithmic form:
We shall now give the following
DEFINITION OF A LOGARITHM. The power to which a given number called the base must be raised to equal a second number is called the logarithm of the second number.
(d) logs 729 = 5. (j) Iog2 1/8 = - 3. (c) logs 625 = 4. (fc) logn 1 = 0. (/) log» 1728 = 3. (0 loga o = l.
64. Properties of Logarithms. Any positive number, except 1, may be the base of a system of logarithms of all the real positive numbers. In any such system,
65. Computation of Common Logarithms. While any positive number except unity could be used as the base of a system of logarithms, only two systems are in general use. One, called the natural, or Napierian system is used in analytical work and has the number e = 2.71828 + for its base. The other, known as the common, or Briggs system is used for all purposes involving merely numerical computations and has for its base the number 10. Unless specifically stated to the contrary the common system will be the one used throughout this book.
written as an abbreviation of logio x.
Every positive number has a common logarithm, and the value of this logarithm may be obtained correct to as many places of decimals as may be desired. Negative numbers and zero have no real logarithms.
If we extract the square root of 10, the square root of the result thus obtained, and so on, continuing the reckoning in each case to the fifth decimal figure, ,we obtain the following table :
EXAMPLE. Find the common logarithm of 4.26.
Divide 4.26 by the next smaller number in the table, 3.16228. The quotient is 1.34719. Hence 4.26 = 3.16228 X 1.34719. Divide 1.34719 by the next smaller number in the table, 1.33352. The quotient is 1 0102. Hence 4.26 = 3.16228 X 1.33352 X 1.0102. Continue thus, always dividing the quotient last obtained by the next smaller number in the table. We shall obtain by this method an expression for 4.26 in the form of a product:
When the logarithm of a number is not an integer it may be represented approximately by a decimal fraction correct to any desired number of places; thus log 426 = 2.6294 to four decimal places.
The integral part of the logarithm is called the characteristic and the decimal part is called the mantissa. In log 426, the characteristic is 2 and the mantissa is .6294. For convenience in computing it is desirable to have the mantissa positive even when the logarithm is a negative number. For example, log \ = - 0.3010, but - 0.3010 = 9.6990 - 10, and we write
Moving the decimal point n places to the right (left) in a number increases (decreases) the characteristic of its common logarithm by n, but does not affect its mantissa.
words, the common logarithms of two numbers which contain the same sequence of figures differ only in their characteristics. Hence, tables of logarithms of numbers contain only the mantissas and the computer must determine the characteristics mentally. This can be done by the following simple rules.
On the other hand if N is a decimal fraction (i. e., a positive number less than 1), we may move the decimal point 10 places to the right and apply Rule I., provided we subtract 10 from the resulting logarithm. For example,
the number so obtained subtract 10.
. A very large number such as the distance in feet from the earth to the sun, 490,000,000,000 (correct to two significant figures), is conveniently written (on moving the decimal point 11 places to the left) in the form
and the characteristic of its common logarithm is 11. Similarly a very small number such as 0.000,000,453,8 can be written (on moving the decimal point 7 places to the right),
This form of expression is frequently used where only a few significant figures are known to be correct, and if the decimal point is placed after the first significant figure, the exponent of 10 is the characteristic of the logarithm of the number.
67. Use of Tables. 1) The characteristic is not given in the table of logarithms. It is to be found by the above two rules. It should be written down first, and always expressed even though it be zero, in order to avoid error due to forgetting it.
2) The mantissa of the common logarithms of numbers, correct to four decimal places, are printed in Table I., at the end of the book. For convenience in printing the decimal points are omitted.
To find the mantissa of a number consisting of one, two, or three digits (exclusive of ciphers at the beginning or end, and the decimal point), look in the column marked N for the first two digits and select the column headed by the third digit; the mantissa will be found at the intersection of this row and this column. For example, to find the mantissa of 456, we run down the column headed N to 45 and then run across the page
68. Interpolation. If there are more than three significant figures in the given number, its mantissa is not printed in the table; but it can be found approximately by the principle of proportional parts: when a number is changed by an amount which is very small in comparison with the number itself, the change in the logarithm of the number is nearly proportional to the change in the number itself.
The difference between these mantissas, called the tabular difference, is 11. We note that an increase of 10 in 3760 produces an increase of 11 in its mantissa and we conclude that an increase of 8 in 3760 (to bring it up to 3768, the given digits) would produce an increase of .8 X 11 = 8.8 in the mantissa. This number 8.8, called the correction, is to be added to the
Near the beginning of Table I. the tabular differences are so large as to make this process of interpolation inconvenient and in some instances unreliable. On this account there are printed on the third and fourth pages of Table I., the mantissas of all four figure numbers whose first digit is 1. By using these we can avoid interpolation at the beginning of the table. Thus, on the third page of the table we find,
EXAMPLE 1. Find the logarithm of .003467. Opposite 34 in column 6 find 5391; the tabular difference is 12; .7 X 12 = 8.4; the mantissa is then 5391 + 8 = 5399; hence log .003467 = 7.5399 - 10
EXAMPLE 2. Find log 2.6582. Opposite 26 in column 5 find 4232; the tabular difference is 17; .82 X 17 = 13.9; the mantissa is 4232 + 14 = 4246; hence log 2.6582 = 0.4246.
69. Accuracy of Results. The accuracy of results obtained by means of logarithms depends upon the number of decimal places given in the tables that are used, and this accuracy has reference to the significant figures counted from the left. In general, a table will give trustworthy results to as many significant figures, counted from the left, as there are decimal places given in the logarithms. For example, four-place logarithms would show no difference between 35492367 and 35490000.
Neither a four-place nor a five-place table would be of any use in financial computations where large sums are involved. It would take a nine-place table to yield exact results if the sums involved should reach a million dollars.
70. Reverse Reading of the Table. To find the number when its logarithm is known. This is sometimes called finding the antilogarithm. For this process we have the following rule.
RULE III. // the mantissa is found exactly in the table, the first two figures of the corresponding number are found in the column N of the same row, while the third figure of the number is found at the top of the column in which the mantissa is found.
We find the mantissa 7427 in the row which has 55 in column N. The column in which 7427 is found has 3 at the top. Thus the significant figures in the number are 553. Since the characteristic is 1 we must have 2 figures to the left of the decimal point. Thus N = 55.3.
RULE IV. When the given mantissa is not found in the table, write down three digits of the number corresponding to the mantissa in the table next less than the given mantissa, determine a fourth digit by dividing the actual difference by the tabular difference, and locate the decimal point so that the rules for characteristics are fulfilled.
The mantissa 4675 is not recorded in the table, but it lies between the two adjacent mantissas 4669 and 4683. The mantissa 4669 corresponds to the number 293. The tabular difference is 14. The actual difference between 4669 and 4675 is 6. The number 4675 is 6/14 of the interval from 4669 to 4683, and the corresponding number N is
In practice this is done mentally by beginning at the left not omitting the characteristic, and subtracting each digit from 9, except the last significant digit, which is subtracted from 10.
In the process of division subtracting the logarithm of a number and adding its cologarithm are equivalent operations since dividing by N is equivalent to multiplying by its reciprocal.
72. Computation by Logarithms. It should be kept in mind that a logarithm is unchanged if at the same time any given number is added to and subtracted from it. This is useful in two cases:
34. The amount a of a principal p at compound interest of rate r for n years is given by the formula: a = p(l + r)n. Find the amount of $486 in 5 years at five per cent, (r = .05) if the interest is compounded annually. Ans. $620.27
36. Find the simple interest on $6,237.43 for 7 years at six per cent. Would the computation made with four-place logarithms, be sufficiently accurate for commercial purposes? Explain. Ans. $2619.72.
where x takes one of the values 5, 7, or 10, C being the maximal central visual acuity, VPi the visual field, A/Af the action of the extrinsic muscles, Cj and C2 the central visual acuity of each eye, and A/P2 the peripheric vision. Compute the value of # if C = 1, PI = 1, M = 1, Ci = 1, Cs = 0.58, x = 10, P2 = 1. Ans. 97.2%
where F — functional ability, V = necessary knowledge, K — the ability to compete (demand for him), x has one of the values 5, 7, or 10. Compute E for F = 0.78792, V = 1, x = 10, K = 0.39396.
46. When w grams of a substance is dissolved in v liters of water at t° centigrade, the osmotic pressure, p, of the solution and the molecular weight, M, of the solute are connected by the equation
73. The Slide Rule. The slide-rule is an instrument for carrying out mechanically the operations of multiplication and division. It is composed of two pieces, usually about the shape of an ordinary ruler; one of the pieces (called the slide,) fits in a groove in the other piece. Each piece is marked in divisions
number ab on scale A.
Divisions can be performed by reversing this process. Thus if 6 on scale B be set opposite c on scale A, the 1 on scale B will be opposite c/b on scale A.
actual procedure in any case.
Scales C and D are made just twice the size of scales A and B. It follows that any number on scale C, for example, is exactly opposite the square of that number on scale A. This facilitates the finding of squares and square roots, approximately.
Scales C and D may be used in place of scales A and B for multiplication and division. Indeed, after some practice, scales C and D will be preferred for this purpose.
More elaborate slide-rules, marked with several other scales, are for sale by all supply stores. Descriptions of these and full directions for their use will be found in special catalogs issued bv instrument makers.
A simple slide-rule can be bought at a moderate price. One sufficient for temporary practice may be made by the student by cutting out the large figure printed on one of the fly-leaves of this book, and following the directions printed there.
processes.
As exercises the teacher may assign first very simple products and quotients. When the operation of the slide-rule has been mastered, the student may check the answers to the exercises on p. 86.
TRIGONOMETRY
74. Introduction. The sides and angles of a plane triangle are so related that any three given parts, provided at least one of them is a side, determine the shape and the size of the triangle.
triangle from the numerical values of the given parts.
Geometry shows in a general way that the sides and angles of a triangle are mutually dependent. Trigonometry begins by showing the exact nature of this dependence in the right triangle, and for this purpose employs the ratios of the sides.
75. Definitions of Trigonometric Functions. Let A be any acute angle. Place it on a pair of axes as in Fig. 24, with the vertex at the origin, one side along
the ar-axis to the right, and the other side in the first quadrant. On this side choose any point M (except 0) and drop M N perpendicular to the or-axis. Let OM = r; then by plane geometry,
y ordinate
These six ratios are called the trigonometric functions of the angle A. They do not at all depend upon the choice of the point M on the side of the angle but only upon the magnitude of the angle itself.
From these definitions we deduce the following relations which are of fundamental importance in computing the unknown parts of right triangles.
complementary acute angle.
77. Functions of 30°, 45°, 60°. On the sides of a right angle lay off unit distances A B and AC and draw BC, forming an isosceles right triangle, Fig. 28. The angles at B and C are each 45°, and the hypotenuse BC is equal to V2~ (why?).
Construct an equilateral triangle whose sides are 2 units long, Fig. 29. Bisect one of its angles forming a right triangle ACD, in which A = 60°, C = 30°, and the altitude CD is equal to A/3 (why?). Then from the definitions,
The values of these functions can also be found graphically by constructing a right triangle the ratio of whose sides are such as to make the sine of one angle equal to 1/2. This can evidently be done by making the side opposite equal to 1 and the hypotenuse equal to 2; then the side adjacent is equal to >/3. (Why?) The other functions can now be read directly from the
79. Solution of Right Triangles. The values of the six trigonometric ratios have been computed for all acute angles, and recorded in convenient tables. They are given to four decimal places in Table II, at the end of the book. These tables, together with the definitions of the functions, enable us to solve all cases of right triangles.
estimate their values.
(2) // one of the given parts is an acute angle, consider the relation of the known parts to the one which it is desired to find, and apply the appropriate one of formulas (7), (8), (9), p. 93.
ploys the two given sides.
(4) Check the results. The larger side must be opposite the larger angle, and the square of the hypotenuse must be equal to the sum of the squares of the other two sides.
The following examples illustrate the process of solution.
EXAMPLE 1. Given the hypotenuse = 26, and one angle = 43° 17'; find the two sides and the other acute angle. Do not use logarithms.
Draw a figure ABC in which AC = 26, A = 43° 17' and denote the unknown parts by suitable letters, x, y, and C. Find C as the complement of
EXAMPLE 3. The hypotenuse of a right triangle is 42.7 and one side is 18.5. Find the other parts. To find one of the angles, as C, note that the hypotenuse and side adjacent are known. Then
81. Graphical Solution. As shown in § 35, if the triangle be drawn to scale, the unknown sides can be read off on the scale, and the unknown angles on a protractor. The results so obtained will be accurate enough to detect any large errors in the computations.
1. Solve graphically the following triangles:
(a) a = 5, b = 4, c = 7. Ans. A = 44° 30', B = 34°, C = 101° 30'. Ans. A = 22°, B = 60°, C = 98°. Ans. A = 38°, B = 60°, C = 82°.
3. The width of the gable of a building is 32 ft. 9 in. The height of the ridge of the roof above the plates is 14 ft. 6 in. Find the inclination of the roof, and the length of the rafters.
6. A cord is stretched around two wheels with radii of 7 feet and 1 foot respectively, and with their centers 12 feet apart. Find the length of the cord. Ans. 12 V3 + 10w = 52.2 ft.
7. Two objects A, B in a rectangular field are separated by a thicket. To determine the distance between them, the lines AC = 45 rods, BC = 36 rods, are measured parallel to the sides of the field. Find the distance AB. Ans. 57.63
8. One bank of a river is a bluff rising 75 ft. vertically above the water. The angle of depression of the water's edge on the opposite bank is 20° 27'. Find the width of the river. Ans. 201.1
9. A smokestack is secured by wires running from points on the ground 35 ft. from its base to points 3 ft. from its top. These wires are inclined at an angle of 40° to the ground, (a) What is the height of the smokestack? (6) The length of the wires? (c) What is the least number of wires necessary to secure the stack? If they are symmetrically placed, how far apart are their ground ends? (d) How far are the lines joining their ground ends from the foot of the stack? (e) From the top of the stack? (/) What angle do the wires make with these lines? (<?) With each other? (h) What angle does the plane of two wires make with the ground? (i) What angle does the perpendicular from the foot of the stack on this plane make with the ground? (j) What is its length? [DURFEE]
10. A tree stands on a horizontal plane. At one point in this plane the angle of elevation of the top of the tree is 30°, at another point 100 feet nearer the base of the tree the angle of elevation of the top is 45°. Find the height of the tree.
11. Find the length of a ladder required to reach the top of a building 50 ft. high from a point 20 ft. in front of the building. What angle would the ladder in this position make with the ground?
82. General Angles. Rotation. Up to this point we have defined and used the trigonometric functions of acute angles only. Many problems require the consideration of obtuse angles and others, particularly those concerned with the rotating parts of machinery, involve angles greater than 180° or 360° even, and it is necessary to distinguish between parts in the same or parallel planes which rotate in the same or in opposite directions.
generated by clockwise rotation is said to be negative. In drawings a curved arrow may be used to show the direction of rotation, the arrow head indicating the terminal side.
on the terminal side and let x, y be its coordinates (positive, negative, or zero depending upon the position of P in the plane) ; let r be the distance from 0 to P (always positive). Then the trigonometric functions of $ are defined as follows:
These definitions apply of course to all acute angles and give the same values as the definitions in § 75. These new definitions are more general because they apply to angles to which the former do not apply.
These ratios are independent of the choice of P on the terminal side of the given angle. They depend upon the magnitude and sign of the angle. For, if we choose a different point P' on the terminal side of <£, we shall have
The signs of the trigonometric functions of an angle 0 depend upon the quadrant of the plane in which the terminal side of <f> falls when it is placed on the axes. An angle <£ is said to be an angle in the first quadrant when its terminal side falls in that quadrant, and similarly for the second, third, and fourth quadrants. The signs of the sine and the cosine of an angle in each of the quadrants should be thoroughly learned. The accompanying diagram indicates these signs.
The signs of the other functions are determined by noting that tan <£ is positive when sin <£ and cos <j> have like signs and negative when they have unlike signs; and that reciprocals have like signs.
tions. The fundamental identities (10) to (18) which were proved for acute angles in § 78 are valid for any angle whatever. The proofs which are similar to those already given are left to the student.
85. Quadrantal Angles. Let P be a point on the terminal side of an angle 0 at a distance r from the origin.
Often it is said that tan 90° = °o } but this does not mean that 90° has a tangent; it means that as an angle 0 increases from 0° to 90°, tan 0 increases without limit, and that before $ reaches 90°. Similar remarks apply to the statements ctn 0° = oo , tan 270° = oo , etc.
86. Line Representations of the Trigonometric Functions. The trigonometric functions denned in § 83 are abstract numbers; each is the ratio of two lengths. They are not lengths nor lines. They can however very conveniently be represented by line segments in the sense that the number of length units in the segment is equal to the magnitude of the function, and the sign of the segment is the same as the sign of the function.
Let an angle 0 of any magnitude and sign be placed on the axes, Fig. 39. With the origin as center and a radius one unit length draw a circle cutting the positive z-axis at A, the positive y-axis at B, and the terminal side of 0 at P. Draw tangents to this circle at ^4. and at B and produce the terminal side in one or both directions from 0 to cut these tangents in T and S respectively. Draw PQ perpendicular to the z-axis. Then, if we agree that QP shall be positive upward, OQ shall be positive to the right, and that OT, or OS, shall be positive when it has the same sense as OP and negative when it has the opposite sense,
QP represents sin 0, OQ represents cos 0, A T represents tan 0, AS represents ctn 0, OT represents sec 0, OS represents esc 0.
For, sin </» = QP/OP = the number of units of length in QP since OP = unit length and sin $ and QP agree in sign from quadrant to quadrant. Similarly the others may be proved.
87. Congruent Angles. Any angle formed by adding to or subtracting from a given angle <f>, any multiple of 360° is said to be congruent to 0; thus — 217° and 143° are congruent. It is obvious from the definitions and from the line representations of the functions of an angle that two congruent angles have equal functions. The functions of any angle formed by adding to or subtracting from a given angle a multiple of 360° are the same as the corresponding functions of the given angle.
88. Trigonometric Equations. To solve the equation sin x = 1/2 is to find all angles which satisfy it. We know that x = 30° is a solution for sin 30° = 1/2; x = 150°, x = - 210°, x = 750°, are also solutions. We can find all its solutions by the following graphical method.
where s is a given number between - 1 and + 1, draw a unit circle center at the origin and on the y-Sixis lay off OB = s (above 0 if s > 0, below if s < 0) and through B draw a parallel to the z-axis cutting the circle in C and D, Then the positive angles
are solutions (and the only solutions between 0° and 360°) of the given equation. Any angle congruent to a or to /3 is also a solution, and there are no others. These results follow directly from the line representations of the functions in § 86. 2) To solve the equation
where c is a given number between — 1 and + 1, draw a unit circle center at the origin, Fig. 41, and lay off on the z-axis OB = c (to the right if c > 0, to the left if c < 0) and draw through B a parallel to the 7/-axis cutting the circle in C and D. Then the positive angles
are solutions (and the only solutions between 0° and 360°) of the given equation. Any angle congruent to a or to /3 is also a solution and there are no others.
are solutions (and the only solutions between 0° and 360°) of the given equation. Any angle congruent to a or to /3 is also a solution, and there are no others.
Many other trigonometric equations can be reduced to one of these three forms by the transformations given in § 78 and hence can be solved by the above methods.
the left side, and factoring.
8Q. Graphs of the Trigonometric Functions. The variation in the sine of a given angle as the angle increases from 0° to 360° may be exhibited graphically as follows.
circle into a convenient number of equal arcs. In Fig. 43, the points of division are marked 0, 1, 2,3, ••• 12. The length of the circumference is approximately 6.3; lay this off on the z-axis (Fig. 44) and divide it into the same number of equal parts and number them to correspond with the points of division on the circumference.
At each point of division on the a>axis lay off vertically the line representation QP, of the sine of the angle whose terminal side goes through the corresponding point of division on the circle. Connect the ends of these perpendiculars by a smooth curve. This is called the sine curve or the graph of sin x.
As the angle increases from 0° to 360°, P moves along the circle successively through the points 0, 1, 2, 3, •••, 12, Q' moves along the z-axis successively through the corresponding points 0, 1, 2, 3, • • •, 12, and P' traces the sine curve.
If the angle increases beyond 360°, P makes a second revolution around the circle, and the values of all the trigonometric functions repeat themselves in the same order and the graphs from x = 6.3 to x = 12.6 will in all cases be a repetition of those from x = 0 to x = 6.3. If P goes on indefinitely the graph will be repeated as many times as P makes revolutions.
Functions which repeat themselves as the variable or argument increases are called periodic functions. The period is the smallest amount of increase in the variable which produces the repetition of the value of the function. Thus, sin a; is a periodic function with a period of 360°, while the period of tan x is 180°.
lay off OP' = OP and draw PPf. Let x, y be the coordinates of P and x', y' those of P'; let OP = r and OP' = r'. Then no matter what the magnitude or sign of 4>,
angle </> be placed on the axes; draw a circle, center at the origin, with any convenient radius r, cutting the terminal side of 0 in P and the terminal side of <f> + 90° in Q. Let the coordinates of P be (a, &); then no matter in what quadrant P is, Q is in the next quadrant and its coordinates are (—6, a), for the right triangles OMP and QNO have the hypotenuse and an acute angle of the one equal to the hypotenuse and an acute angle of the other. Then by the definitions, § 83
92. Functions of ± 9, 90° ± 6, 180° ± 0, 270° ± 6. If we put for 0 in succession, - 6, 6, 90° - 6, 90° + 6, 180° - 0, 180° + 6, 270° - 9, 270° + 6, we obtain the values in the following table, 6 being any angle.* By drawing diagrams the results tabulated can be verified. The student is advised to do this.
function does not change name.
EXAMPLE 1. sin 177° = sin (180° - 3°) = + (rule 1) sin (rule 2) 3°. EXAMPLE 2. cos 177° = cos (90° + 87°) = - (rule 1) sin (rule 2) 37°. EXAMPLE 3. tan300° = tan (180° + 120°) = + (rule 1) tan (rule2) 120°.
93. Plotting Graphs from Tables. For many purposes, such as the measurement of arcs and the speed of rotations, and generally in the calculus and higher mathematics, angles are measured in terms of a unit called the radian.
A radian is a positive angle such that when its vertex is placed at the center of a circle the intercepted arc is equal in length to the radius. This unit is thus a little less than one of the angles of an equilateral triangle, 57°. 3 approximately. It is easy to change from radians to degrees and vice versa, by remembering that
Unless some other unit is expressly stated, it is always understood that in graphs of the trigonometric functions the radian is the unit angle and that 1 unit on the x-axis represents 1 radian. These graphs can be constructed from a table of their values such as Table III at the end of the book. Thus to plot the graph of sin x, draw a pair of rectangular axes on squared paper
and mark the points 1, 2, 3, • • • on the x-axis. These unit lengths are divided by the rulings of the cross-section paper into tenths. At each of these points of division on the x-axis lay off parallel to the y-axis the sine of the angle from the table, e. g., at 1 we plot AP = .84 = sin 1 (radian). The curve may be extended beyond the first quadrant by the principles of § 92. Similarly the graphs of cos x and tan x can be plotted from their tabulated values.
4. Simplify each of the following expressions.
(a) sin (90° + x) sin (180° + x) + cos (90° + x) cos (180° - x). (6) cos (180° + x) cos (270° - y) - sin (180° + x) sin (270° - y). (c) sin 420° cos 390° + cos (- 300°) sin (- 330°).
8. In each of the following equations find graphically the two solutions which are between 0° and 360° and compute the values of the other five functions of each of these angles.
94. Sine and Cosine of the Sum of two Angles. Let
AOB = x, BOC = y, then AOC = x + y. With 0 as center and a convenient radius r > 0, strike an arc cutting OC in P. Drop PQ perpendicular to OB, also PR and QS perpendicular to
x and y. They are called the addition formulas.
It is readily proved that if x = a and y = /3 are any two acute angles for which these formulas hold good they will hold good for any two of the angles a, ft, a + 90°, a - 90°, /3 + 90°, /3 — 90°. Therefore, since we have found that they hold good for all acute angles, they hold good for all positive or negative angles of any magnitude whatever.
97. Functions of Half an Angle. The preceding formulas are true for all values of x for which they have a meaning. Hence we may replace x by any other quantity. If we write x/2 in place of x in (28) and (29), § 96, and solve the resulting equations for sin (z/2) and cos (z/2), we find
19. Prove each of the following identities, (a) cos (A + B) cos (A - B) = cos2 A - sin2 B. (6) sin (A + B) cos B — cos (A + B) sin B = sin A.
(i) cos £ sin (y — z) + cos y sin (z — x) + cos z sin (x — y) = 0. 0') sin A + sin 5 = 2 sin f(A + 5) cos f (A - B). (fc) sin A - sin B = 2 cos i(^ + B} sin |(A - B).
(m) cos A — cos 5 = — 2 sin |(A + .B) sin %(A — B). (n) sin A cos (B — C) — sin £ cos (A. — C) = sin (A. — JB) cos C. (o) cos2 %<f>(l + tan |0)2 = 1 + sin 0. (p) sin2 |x(ctn |x — I)2 = 1 — sin x.
98. Solution of Oblique Triangles. One of the chief uses of trigonometry is to solve triangles. That is, having given three parts of a triangle (sides and angles) at least one of which must be a side, to find the others. In plane geometry it has been shown how to construct a triangle, having given
CASE IV. Three sides.
When the required triangle has been constructed by scale and protractor the parts not given may be found by actual measurement. The results obtained by such graphic methods are not, however, sufficiently accurate for many practical purposes.
Nevertheless, they are very useful as a check upon the computed values of the unknown parts. Other checks are furnished by the theorems of plane geometry that the sum of the angles of any triangle is 180°, and that if two sides (angles) are unequal the greater side (angle) lies opposite the greater angle (side). The properties of isosceles triangles can also be used in certain special cases.
The direction solve a triangle tacitly assumes that a sufficient number of parts of an actual triangle are given. A proposed problem may violate this assumption and there will be no solution. Thus, there is no triangle whose sides are 14, 24, and 40 ; likewise, there is no triangle of which two sides are 9 and 10 and the angle opposite the former is 64° 10'. Any triangle which can be constructed can be solved.
Any oblique triangle can be divided into right triangles by a perpendicular from a vertex upon the opposite side, and this method when applied to the various cases leads to three laws, called the law of sines, the law of cosines, and the law of tangents, by means of which the unknown parts of any oblique triangle can be computed. We proceed to prove these laws.
other as the sines of the opposite angles.
In any oblique triangle let a, b and c be the measures of the lengths of the sides and A, B, and C the measures of the angles opposite. Drop the perpendicular CD = p from the vertex of angle C to the opposite side.
It is evident that a triangle may be solved by the aid of the law of sines if two of the three known parts are a side and its opposite angle. The case of two angles and the included side being given, may also be brought under this head, since we may find the third angle which lies opposite the given side.
100. Law of Cosines. In any triangle, the square of any side is equal to the sum of the squares of the other two sides minus twice the product of these two sides into the cosine of their included angle.
These formulas may be used to find the angles of a triangle when the three sides are given and also to find the third side when two sides and the included angle are given.
101. Law of Tangents. The sum of any two sides of a triangle is to their difference as the tangent of half the sum of their opposite angles is to the tangent of half their differ&nce.
As a check, (38) is the more convenient form, while for solving triangles, (39) is preferred by some computers. If 6 > a, then B > A. The formula is still true, but to avoid negative numbers the formula in this case should be written in the form
angles A and B.
102. Methods of Computation. The method to be used in computing the unknown parts of a triangle depends on what parts are given. In what follows triangles are classified according to the given parts and the methods of computation are stated and illustrated by examples.
103. Case I. Given two Angles and one Side. There is always one and only one solution, provided the sum of the given angles is less than 180°.
The third angle is found by subtracting the sum of the two given angles from 180°. The unknown sides are found, successively, by the law of sines.
then the rule: Multiply the pair of knowns and divide by the known in the other pair; or, Add the logarithms of the pair of knowns and the cologarithm of the known in the other pair.
Similarly we may compute c. Using logarithms, we find c = 267.7. Not using logarithms, we find 267.6. The difference in the two answers is due to the slight inaccuracy caused by our using only four decimal places.
104. Case II. Given two Sides and the Angle opposite one of Them. This case sometimes admits two solutions and on this account is called the ambiguous case. The number of solutions can be determined by constructing the triangle to scale as follows.
To fix our ideas, let the given angle be A, the given opposite side a, and the given adjacent side 6. Construct the given angle A, and on one of its sides lay off AC = b, the given adjacent side, and drop a perpendicular CP, of length p, from C to the other side of the given angle A. With C as center and with radius o, the given opposite side, strike an arc to determine the vertex of the third angle B. Several possible cases are shown in Fig. 54.
A study of these diagrams shows that there will be two solutions when, and only when, the given angle is acute and the length of the given opposite side is intermediate between the lengths of the perpendicular and the given adjacent side; that is
To solve the triangle AB&, we first find BI = 129° 37' being the supplement of 52, and then the third angle Ci = 16° 00'. To find Ci (i. e., the side ABi) use the law of sines,
3. A 50 ft. chord of a circle subtends an angle of 100° at the center. A triangle is to be inscribed in the larger segment having one side 40 ft. long. How long is the third side? How many solutions?
105. Case III. Given two Sides and the included Angle.
There is always one and only one solution. The third side can be found by the law of cosines and if the angles are not required, this is a convenient method of solution, especially if the given sides are not large.
If the other two angles as well as the third side are required, the two angles should be found by the law of tangents and then the third side can be found by the law of sines. Both these computations can be made by logarithms.
4. To find the distance between two objects A and B, separated by a swamp, a station C is selected so that CA = 300 ft., CB = 277 ft., and angle ACB = 65° 47', can be measured. Compute AB.
106. Case IV. Given the three Sides. There is one and only one solution, provided no side is greater than the sum of the other two.
25 = 49 + 64 - 2 X 7 X 8 cos B, cos B = -B = 0.7857, B = 38° 13'. 64 = 25 + 49 - 2 X 5 X 7 cos C, cos C = | = 0.1429, C = 81° 47'. CHECK. 60° + 38° 13' + 81° 47' = 180° 00'.
107. Area of a Triangle. It is shown in plane geometry that the area of a triangle is equal to one half the product of any side and the perpendicular from the opposite vertex upon that side.
4. Venus is nearer to the Sun than the Earth. Assume that the orbit of Venus is a circle with the Sun at its center. The distance from the Earth to the Sun is 92.9 millions of miles. What is the distance from Venus to the Sun if the greatest angular distance of Venus from the sun as seen from the Earth is 46° 20'? Ans. 67,200,000 mi.
5. On a clear day, twilight ceases when the sun has reached a position 18° below the horizon (HAS = 18°) . Find the height AE of the atmosphere which is sufficiently dense to reflect the sun's rays. Take OC = 4,000 miles. The result must be diminished by 20% to allow for refraction. [MORITZ] . Ans. 40 miles.
6. The mean distances of the Earth and Mars from the sun are 92.9 and 141.5 millions of miles respectively. How far is Mars from the Earth when its angular distance from the sun is 28° 10' ?
Ans. 21,280,000 mi.
7. From two points on the same meridian, the zenith distances of the moon are 35° 25' and 40° 11'. The difference in latitude between the points of observation is 74° 26'. Find the distance of the moon from the earth, assuming the FIG. 62 radius of the earth as 3,959 miles. [MORITZ]
Ans. 239,000 miles, approximately.
8. A search light 20 feet above the edge of a tank is directed to a point on the surface of the water 40 feet from the edge. If the tank is 15 feet deep how far will be the illuminated spot on the floor of the tank from the edge, the index of refraction being 4/3? Ans. 62.5 ft.
9. A man whose eye is 6 feet above the edge of a tank 10 feet deep sees a coin in a direction making an angle of 34° with the surface of the water. If the index of refraction is 4/3, how far is the coin from the side of the tank? Ans. 16.83 ft.
10. Three forces of 12, 16, and 22 pounds in equilibrium can be represented by the 3 sides of a triangle taken in order. Find the angles which they make with each other.
11. A sharpshooter and an enemy are 220 feet apart and on the same side of a street 100 feet wide. Both are concealed by buildings. A bullet striking a building on the opposite side of the street at an angle x is deflected from the building at an angle y so that 3 sin a; = 4 sin y. Find x so that the sharpshooter may be able to hit the enemy.
12. A ship is going 15 miles per hour. How far to the side of a target 1 mile distant must the gunner aim if the shot travels 2000 ft. per second and the shot is fired when directly opposite?
13. An aeroplane is observed from the base and from the top of a tower 40 feet high. The angles of elevation are found to be 10° 40' and 9° 50'. Find the distance from the base to the plane and the height of the plane. Ans. 2713 ft., 502.4 ft.
14. To determine the distance of a hostile fort A from a place B, a line BC and the angles ABC and BCA were measured and found to be 1006.6 yd., 44°, and 70°, respectively. Find the distance AB.
Ans. 1,036 yd.
15. In order to find the distance between two objects, A and B, separated by a pond, a station C was chosen, and the distance CA = 426 yd., CB = 322.4 yd., together with the angle ACB = 68° 42', were measured. Find the distance from A to B. Ans. 430.9 yd.
16. A surveyor wished to find the distance of an inaccessible point 0 from each of two points A and B, but had no instrument with which to measure angles. He measured A A' = 150 ft. in a straight line with OA, and BE' — 250 ft. in a straight line with OB. He then measured AB = 279.5 ft., BA' = 315.8 ft,, A'B' = 498.7 ft. From these measurements find each of the distances AO and BO.
Ans. 152.3 ft., 319.7 ft.
17. Two stations, A and B, on opposite sides of a mountain, are both visible from a third station C. The distance AC = 11.5 mi., BC = 9.4 mi., and angle ACB = 59° 30'. Find the distance between A and B.
LAND SURVEYING
108. The Surveyor's Function. Land surveying consists in measuring distances and angles and marking corners and lines upon the ground, and in recording these measurements in field notes from which a map can be drawn and the area computed.
The original survey of a tract of land having been made and recorded, a surveyor may subsequently be called upon to find the corners, to relocate them if lost, to retrace the old boundaries, and to renew the corner posts and monuments if decayed or destroyed. This is called a resurvey.
109. Instruments. Distances
on the ground are measured with the chain or tape. The land surveyor's chain is 66 feet (4 rods) long and is divided into 100 links each 7.92 inches long. The steel tape is usually 100 feet long, subdivided to hundredths of a foot.
transit. This is an instrument
mounted on a tripod, and composed of the following parts: (a) the telescope provided with cross hairs to determine the line of sight, a sensitive spirit level, and a graduated circle on which the
angular turn of the telescope in the vertical plane is read; (6) the alidade, carrying the telescope, provided with spirit levels to bring its base into the horizontal plane and a large graduated circle on which is read the angular turn of the telescope in measuring horizontal angles; and (c) the magnetic compass.
110. Bearing of Lines. The direction of a line on the ground may be given by its bearing; this is the angle between the line and the meridian through one end of it. For example, a line bearing N 26° E is one which makes an angle of 26° on the east side of north; one bearing S 85° W makes an angle of 85° on the west side of south. The bearing of a line which is run by the transit is read off on the compass circle but is subject to a correction depending upon the time and place since the magnetic needle does not point due north at all times and places.
111. Government Surveys. In government surveys of the public lands, a north and south line called a principal meridian is first accurately laid out and marked by permanent monuments. From a convenient point on the principal meridian a base line is run east and west and carefully marked. North and south lines, called range lines, are then run from points six miles apart on the base line. Then township lines six miles apart are run east and west from the principal meridian.
The land is thus divided into townships six miles square. A tier of townships running north and south is called a range. Ranges are numbered consecutively east and west from the principal meridian. Townships are numbered north and south from the base line.
In deeds and records a township is located, not by the county, but as " Township No. — north (or south) of a certain base line and in range No. — east (or west) of a certain principal meridian. Townships are divided into thirty-six sections each one mile square containing 640 acres, and are numbered from
The first principal meridian runs north from the junction of the Ohio and Big Miami rivers on the boundary between Ohio and Indiana. The second coincides with 86° 28' of longitude west of Greenwich running north from the Ohio river near the towns of English, Bedford, Lebanon, Culver, Walkerton, and Warwick, Indiana. The surveys in Indiana (with the exception of certain lands in the southeast corner) are governed by this second principal meridian and a base line in latitude 38° 28' 20" crossing this meridian about 5 miles south of Paoli, in Orange County.* Thus a certain parcel of land is described in the Indiana records as " E \ of NW \ of Section nineteen (19), Township twenty-three (23) N, Range four (4) W."
The surveys extending east from one meridian will not generally close with those extending west from the preceding meridian; the same is true of the ranges of townships extending north
* The first six principal meridians are designated by number ; some twenty -odd others by name. E. g., the Mount Diablo meiidian, 120° 54' 48" W, which governs surveys in California and Nevada. The first six base lines are neither numbered nor named but all subsequent ones are named. The locations of all the principal meridians and base lines is given in the Manual of Instructions for the Survey of the Public Lands issued from timo to time by the GENERAL LAND OFFICE, Washington. D. C. For details and a historical sketch see also, PENCE AND KETCHUM, Surveying Manual.
sections.
112. Corners. In an original survey one of the most important of the surveyor's duties is the marking of corners in such a manner as to perpetuate their location as long as possible. The Manual of Instructions (see 1894 edition, p. 44) says, " If the corners be not perpetuated in a permanent and workmanlike manner, the principal object of the surveying operations will not have been attained."
The Instructions prescribe in detail the kind of monument and the mark to be put upon it to establish each of the various kinds of corners that are located in the government surveys. Wooden posts and stakes, stones, trees, and mounds of earth are used. Witness trees or witness points are trees or other objects located near the corner, suitably marked and described in the field notes to make easy a subsequent relocation of the corner.
If called upon to make a resurvey of land that was originally laid out under the direction of the General Land Office, the surveyor will do well to make a careful study of the instructions concerning corners that were in force when the original survey was made, as the practice has varied somewhat from time to time.
113. Judicial Functions of Surveyors.* Many years have elapsed since the greater part of the government surveys were made and in many cases the original corner marks have entirely disappeared. The first settlers and original owners often failed to fix their lines accurately while the monuments remained, and the subsequent owners have no first hand knowledge of their location. When in such cases a surveyor is called upon to
make a resurvey, it is his duty to find if possible where the original corners and boundary lines were, and not at all where they ought to have been. However erroneous the original survey may have been, the monuments that were set must never-^ theless govern, for the parties concerned have bought with reference to these monuments and are entitled only to what is contained within the original lines.
If the original monument and all the witness trees and other identification marks mentioned in the field notes of the original survey have disappeared, the corner is lost and it is the duty of the surveyor to relocate it in the light of all the evidence in the case, including the testimony of persons familiar with the premises, existing fences, ditches, etc., at the point where this evidence shows it most probably was.
In making a resurvey the surveyor has no authority to settle disputed points ; if the disputing parties do not agree to accept his decision, the question must be settled in the courts. In a controversy between adjacent owners over the location of corners and division lines, it is well established in law that a supposed boundary line long accepted and acquiesced in by both parties is better evidence of where the real line should be than any survey made after the original monuments have disappeared. It is common belief that boundary lines do not become fixed by acquiescence in less than 21 years, but there is no particular time that must elapse to establish boundary lines between private owners where it appears that they have accepted a particular line as their boundary and all concerned have claimed and occupied up to it.
114. Measuring on Level Ground. The line to be measured is first ranged out and marked with range poles or its direction is determined by the line of sight of the transit set on the line. The leader sticks a pin at the starting point, takes ten in his hand and steps forward on the line dragging the
chain behind him. At a signal from the follower, given just before the full length has been drawn out, he turns, aligns, and levels the chain, stretches it to the proper tension, and, while the follower holds the rear end at the starting point, sticks a pin at the forward end on the line determined by the follower and a range pole or by the transitman. At a signal from the leader the follower pulls his pin and both move forward on the line another chain's length and set the next pin. This process is repeated until the leader has set his tenth pin, when the follower goes forward, counting his pins as he goes and, if there are ten, hands them to the leader who also counts them. The count of tallies is kept by both. When the end of the line is reached the follower walks forward and reads the fraction of the chain at the pin and notes the number of pins in his hand to determine the distance from the last tally point which is recorded in the field notes.
the count of pins.
116. Offsets. In case measurements cannot be made on the desired line on account of a fence, hedge, pond or other obstacle, a perpendicular to the line, called an offset, is measured, sufficiently long to avoid the obstruction and the measurements are
From any point on a line a right angle (or any other required angle) can be laid off with the transit. An angle of 90° or 60° can be laid off in a clear space with chain or tape and pins as shown in Fig. 68, from the facts that (1) a triangle whose sides are to each other as 3 : 4 : 5 has a right angle opposite the longest side; and (2) an equilateral triangle has three 60° angles.
117. Passing Obstacles. An obstacle in the line can be passed and the line prolonged beyond it by means of perpendicular offsets as shown in Fig. 67, if the nature of the locality makes it convenient.
in Fig. 69. The angle HAB, the distance AB, the angle KBC,
are measured; then the distance BC and the angle MOD are computed; the distance BC is measured off and the point C is located and the angle at C is turned off and the direction CD established; AC is computed
distance AB are arbitrary and may be taken so as to avoid difficulties of the surroundings. If the circumstances permit the angle HAB may be made 60°, and angle KEG = 120°; then the triangle ABC will be equilateral and computations will be avoided.
are invisible each from the other, a line AC, called a random line, is run as nearly in the direction of A B as can be determined and stakes Si, S2, 83, etc., are set at regular measured distances. On coming out near B a perpendicular is let fall from B to AC precisely locating the point C. The lengths of the offsets SiTi, $2^2, $3^3, etc., all perpendicular to AC, can be computed and on retracing CA, stakes can be set at T$, Tt, T3, etc., on the desired line AB. For example, if the stakes on AC are 12 chains apart, if S$C = 6.46 chains, and if BC = 54 links, then the offset, in links, at any stake S, is found by multiplying its distance AS, in chains, from A, by the ratio 54/66.46 = 0.8125. Thus the offset S4T4 = 48 X 0.8125 = 39. It is left to the student to show that A B is longer than AC by less than 1/4 a link and that the stakes on AB are practically 12 chains apart.
119. Computing Areas. If the boundaries of a tract are all straight lines, i. e., if its perimeter is a polygon, the area can be computed by dividing it into triangles, or into rectangles and triangles, provided enough measurements are made so that the required dimensions of each part are known or can be com-
puted. It is customary to measure more lines on the ground than is theoretically necessary in order to check the computations. These extra measurements are called proof lines in the field notes.
120. Irregular Areas by Offsets. When one side of a field is not straight as occurs if the boundary is a stream or curved road, a line may be run cutting off the
any number of sides and prove the following rule.
Multiply each abscissa by the difference of its adjacent ordinatcs, always making the subtractions in the same sense around the perimeter, and take one-half the algebraic sum of the products.
Ans. 16.175 A.
12. Starting on the bank of a river a line is run across a bend 20.00 ch., to the bank again. Offsets are measured every two chains as follows: 1.61, 2.27, 1.96, 4.23, 3.70, 2.92, 3.26, 2.50, 1.25 ch. Make a plot of the land between the line and the river and find the area.
13. Find the measurements so as to run a line from the vertex A of a triangle ABC to a point D on the side BC = 8.75 ch., so as to cut off 2/5 of the area next to B. Ans. BD = 3.50 ch.
14. Find the measurements so as to run a line through a point E on BC of the triangle of Ex. 13, parallel to AB so as to cut off 2/5 of the area in the trapezoid. Ans. CE = 6.78 ch.
15. Two lines meet at P. PA bears S. 65° 30' E., PB bears N. 78° 15' E. Determine measurements to run a line perpendicular to PA so as to cut off five acres. Ans. Base = lOVctn 36° 15' = 11.68 ch.
16. A triangular field contains 6 A. Show how to find on the plot a point inside the triangle from which lines drawn to the vertices will divide it into three triangular fields of 1, 2, and 3 A., and so that the smallest and largest shall be adjacent respectively to the smallest and
20. A tract of land A BCD, lies between two converging streets as shown in Fig. 75. AB = 1980 ft., AC = 590 ft., BD = 1380 ft. Determine the measurements for running lines PQ, RS, etc., perpendicular to AB, so as to divide the tract into ten lots of equal area.
21. From the notes in Ex. 8 (6), make a plot and (a) run a line from S to a point M on PQ so as to divide the field into two parts of equal areas, (6) run a line from R to a point N on SP so as to cut off 10 acres in the triangle.
area is 10.094 acres.
24. It is desired to mark out and measure a line PQ. A random line PR is run and stakes are set on it every 100 ft. The perpendicular from Q upon PR is 48.82 ft. long and meets it at R, 22.18 ft. beyond the 42nd stake. Compute the offsets for setting the stakes over on PQ, their distance apart, and the length of PQ.
25. To prolong a line AB past an obstacle 0, a right turn 40° is made at B, 400 ft. is measured to C, and a left turn of 116° is made. Compute the distance to D on AB produced through O and the right turn which must be made at D. How far from D should hundred foot stakes be resumed?
STATICS
122. Statics. Statics treats of bodies at rest and of bodies whose motion is not changing in direction or in speed. A body whose motion is not changing is said to be in equilibrium. The chief problem of statics is to find the conditions of equilibrium.
123. Mass. The weight, W, of a body is not constant. For instance a body weighs less on a mountain top than at sea level. Also the acceleration, g, due to gravity is not constant. It likewise is less on a mountain top than at sea level. An increase in acceleration is accompanied by a proportional increase in weight. But the ratio W/g is constant. The constant number represented by this ratio is called the mass of the body. A unit of mass is the gram, and is 1/1000 of the mass of a certain piece of platinum which is preserved at Paris. Another unit of mass is the avoirdupois pound. One thousand grams is equal to 2.20462125 Ibs. The mass of any body is then the number expressing the ratio of its weight to the weight of a unit of mass. The weight is to be determined by means of a spring balance.
124. Momentum. When a given mass is in motion, we require to know not only the magnitude of the mass, but also its velocity. The product of the mass of a body and its velocity is called its momentum.
125. Force. If a body possesses a certain amount of momentum, it is impossible for it to alter its motion in any manner unless acted upon by some other body which pushes or pulls it.
Force is that which tends to produce a change of motion in a body on which it acts. This change of motion is proportional to the force and takes place in the direction of the straight line in
which the force acts. Thus, to increase the speed of an automobile, the driving force must be increased. The greater the force, the greater the rate of increase in the speed.
This illustrates the fact that forces are of different magnitudes.
If a motionless croquet ball is struck, its subsequent motion depends upon the direction of the stroke. This illustrates the fact that forces have different lines of action. If a billiard ball is struck, the motion of the ball depends upon the point at which the cue struck the ball. This illustrates the fact that we must take into account the point of application of the force.
A force is said to be completely determined if we know (a) its magnitude; (6) its line of action; (c) its direction along the line of action; (d} its point of application.
In practice forces are never applied at a point. The force is applied over an area such as the pressure of a thumb on the head of a tack or the pressure of a book on a table. A force may act throughout an entire volume as is the case with attraction. These forces are called distributed forces. In practice we often consider the forces which applied at a point would produce the same effect as the given distributed forces. Such forces are termed concentrated forces.
126. Unit of Force. The unit of force is sometimes taken as the weight of a unit mass. This unit of force is not constant. It changes both with altitude and with latitude. These changes are small but for scientific purposes cannot be neglected. To obtain a constant unit it is sufficient to make the following definition :
say at London, Paris, or Washington.
127. Graphic Representation of Forces. A force P is completely determined if we know its magnitude, its line of action, its direction along this line, and its point of application. It
VII, 128J STATICS 155
follows that a force can be completely represented by anything which possesses these attributes. It can, for example, be represented by a directed segment of a straight line. For we may let any point 0, Fig. 76, represent the point of application. From 0 draw any line segment OA the number of units
in whose length is the same as the number of units in the given force. The length of the segment represents then the magnitude of the force. The line of which OA is a part represents the line of action of the force. We can represent the direction along the line by an arrowhead placed on OA.
128. Composition of Forces. — Parallelogram of Forces. If two or more forces act in the same straight line and in the same direction, their resultant, or sum, is obtained by adding the numbers representing the magnitudes of the forces.
their algebraic sum.
When the forces do not act in the same straight line the total or resultant force is found by means of a rule called the parallelogram of forces: If two forces not in the same straight line are represented in direction and in magnitude by two adjacent sides of a parallelogram, the single force which would produce the same effect as the two given forces is represented in direction and in magnitude by that diagonal of the parallelogram which passes through the same vertex as the two given forces.
In Fig. 77, the forces FI and F2 are represented by the lines AB and AC, respectively. Their resultant R is represented by AD. The magnitude of the resultant is given by the equation
The direction a of the resultant force may be found from this equation. Thus R is completely determined. When 6 = 90°, equation (1) reduces to
Two forces which have a given force for their resultant are called the components of this force. Thus FI and F2 are components of R. The process of finding the resultant of any number of forces is known as the composition of forces. The process of finding the components of a given force is called the resolution of forces. Two systems of forces acting on a particle and having the same resultant are said to be equivalent.
spectively, parallel and perpendicular to a given line. Such components are called rectangular components. In this case — the magnitudes of the compon-
Similarly the component of any given force along any given line is equal to the magnitude of the force multiplied by the cosine of the angle between the line and the force.
9. A particle is acted upon by two forces, of 8 and 10 pounds respectively, making an angle of 30° with each other. Find the magnitude of the resultant. Ana. 17.39
10. A boat is being towed by two ropes making an angle of 60° with each other. The pull on one rope is SCO pounds, the pull on the other is 300 pounds. In what direction will the boat tend to move? What single force would produce the same result? [MILLER-LILLY]
11. Let a raft move in a straight line down stream with a uniform speed of 2 feet per second; suppose a man upon the raft walks at a uniform speed of 4 feet per second in a direction making an angle of 60° with the direction of movement of the raft. Find the speed and direction qf_the man relative to the earth.
12. A river one mile wide flows at a rate of 2.3 miles per hour. A man, who in still water can row 4.2 miles per hour, desires to cross to a point directly opposite. Find in what direction he must row and how long he will be in crossing.
minutes approximately.
13. A man in a house observes rain drops falling with a speed of 32 feet per second. The direction of descent makes an angle of 30° with the vertical. Find the velocity of the wind.
Ans. 18.5 ft. per sec.
14. A motor boat points directly across a river which flows at the rate of 3.5 miles per hour; the boat has a speed in still water of 10 miles per hour. Find the speed of the boat and the direction of its motion.
speed and direction.
130. Triangle of Forces. It will be seen at once on referring to Fig. 77 that the sum or resultant of the two forces FI and F2 could be obtained more easily by 7g drawing a triangle ABD, as in Fig. 79;
and opposite to the resultant R were applied at A, this force and the forces FI and Fz would balance, and the point A would be in equilibrium. Another way of stating the proposition would be as follows.
// three concurrent forces are in equilibrium, their magnitudes arc proportional to the three sides of a triangle whose sides, taken in order, are parallel to the directions of the given forces. Conrcrwly, if the magnitudes of three concurrent forces are proportional to the three sides of a triangle and their directions are parallel to the sides taken in order, these forces will be in equilibrium.
1. Draw a triangle ABC whose sides BC, CA, AB are 7, 9, 11 units long. If ABC is a triangle for three forces in equilibrium at a point P, and if the force corresponding to the side BC is a force of 21 Ibs., show in a diagram how the forces act, and find the magnitude of the other two forces. Ans. 27, 33.
2. Draw two lines AB and AC containing an angle of 120°, and suppose a force of 7 units to act from A to B and a force of 10 units from A to C. Find by construction the resultant of the forces, and the number of degrees in the angle its direction makes with AB.
3. Draw an equilateral triangle ABC, and produce BC to D, making CD equal to BC. Suppose that BD is a rod (without weight) kept at rest by forces acting along the lines AB, AC, AD. Given that the force acting at B is one of 10 units acting from A to B, find by construction (or otherwise) the other two forces, and specify them completely.
A and B being in the same horizontal line. When the rope is held taut by a weight W, attached to the middle point, C, of the line, C is four feet below the horizontal line AB. Find the weight of the heaviest boy it will support without breaking. [MILLER-LILLY]
Ans. 117.7, Ibs.
7. A street lamp weighing 100 pounds is supported by means of a pulley which runs smoothly on a cable supported at A and B, on opposite sides of the street. If A is 10 feet above B, and the street 60 feet wide, and the cable 75 feet long, find the point on the cable where the pulley rests, and the tension in the cable. [MILLER-LILLY]
8. A particle of weight W lies on a smooth plane which makes an angle a with the horizon. Show that P = W sin a, R — W cos a, where P is the force acting along the plane to keep the particle from slipping and R is the reaction of the plane.
131. The Simple Crane. One of the most useful applications of the triangle of forces is the case of an ordinary crane. It has a fixed upright member AB called the crane post, a member AC called the jib, and a tie-rod BC, A weight W suspended
rigidly at C is kept in position by three forces in equilibrium. These forces are (a) the weight W, (b) the pull in the tie-rod, and (c) the thrust in the jib. To determine their magnitudes construct to scale a force triangle EFG. Draw EF parallel to the line of action of the weight W and equal to W in magnitude. From F draw F G parallel to the jib and from E draw
EG parallel to the tie-rod. The lengths of EG and FG to the same scale on which EF was drawn represent the thrust in the jib and the pull in the tie-rod. The directions of the forces acting along the tie-rod and jib are given by following around the triangle in order from E to F to G to E.
When a crane is used to raise or lower a weight, the weight is held by a rope passing over a pulley at C. The tension of the rope must now be taken into account.
Suppose a chain or rope supporting the weight is made to pass over a pulley at C, and is then led on to a drum at A round which the rope or chain is coiled. The pull in the rope and tie-rod together is the same as before and is represented by EG. The tension in the rope is the same on each side of the pulley. Therefore if we mark off on EG a distance HE equal to EF, this distance will represent the pull in the rope, thus leaving GH to represent the pull in the tie-rod.
5. The jib of a crane is subjected to a compressive force equal to the weight of 24 tons, the suspended load being 10 tons. If the inclination of the jib to the horizontal is 60°, find the tension in the tierod. Ans. 16.1 tons.
8. The jib of a crane is subjected to a compressive force equal to the weight of 4000 Ibs., the suspended load being 2000 Ibs. If the inclination of the jib to the horizontal is 45°, find the tension in the tie-rod.
132. Polygon of Forces. The resultant of three or more concurrent forces lying in the same plane may be found by repeated applications of the triangle of forces.
Let a particle at 0 be acted upon by any number of forces, Fi, F2, • • • ; to be definite, say Fi, F2, F3, F4. To find their resultant proceed as follows. For the forces FI and F2 construct the triangle of forces OAB (Fig. 81). Then OB is the
resultant of FI and F2. For the forces OB and F3 construct the triangle of forces OBC. The sum is given by OC. In a similar manner combine OC and F4. The resultant is R = OD. The construction of the lines OB and OC is unnecessary and should be omitted. The figure OABCDO is called the polygon of forces. OD, the closing side, is called the resultant. It will be noticed that the arrows on the vectors representing the
while the arrow of the resultant runs in the opposite sense.
If any number of forces acting at a point can be represented by the sides of a closed polygon taken in order, the point is in equilibrium and the resultant is zero.
finding the resultant of any number of forces.
From any point 0 draw a line OA to represent in magnitude and direction the force F\. From the extremity A draw a linc~ AB to represent in magnitude and direction the force F%. Continue thix process for each of the given system of forces. Then the line which it is necessary to draw from 0 to close the polygon represent* the resultant in magnitude and direction.
133. Resultant of Several Concurrent Forces. Analytic Formula. Let any number of forces Fi, F2, •••, lying in the same plane, act on a particle at 0. To fix the ideas, suppose there are three forces. With 0 as origin refer the forces to a pair of coordinate axes, OX and OY (Fig. 82). Resolve each
The given system of forces is equivalent to another set consisting of the rectangular components of the forces of the given system. Let us use the letters X and Y to represent the sum of these components along the x-axis and the 7/-axis, respectively. Then
The two forces X and Y acting at right angles to each other are equivalent to the given system of forces. The single force R which is the resultant of X and Y is also the resultant of the given system of forces. We have
1. If four forces of 5, 6, 8, and 11 units make angles of 30°, 120°, 225°, and 300° respectively, with a fixed horizontal line, find the magnitude and the direction of the resultant. Ans. 7.39 ; — 81° 6'.
3P, 4P.
3. A particle is acted on by five coplanar forces ; a force of 5 Ibs. acting horizontally to the right, and forces of 1, 2, 3, 4 Ibs. making angles of 45°, 60°, 225°, and 300° respectively with the 5-lb. force. Find the magnitude and the direction of the resultant.
134. Resultant of Parallel Forces. Let FI and F2 be two parallel forces acting in the same direction and with their points of application at the points A and B, Fig. 83. At A and B apply two equal and opposite forces, AS and BT, whose line of action coincides with AB. These will balance and will not change the effect of the other forces. Find the resultant AD of AS and FI, and the resultant BE of B T and F2, by constructing the parallelograms of forces. Then by constructing a
parallelogram of forces at 0, the intersection of AD and BE produced, we may find their resultant OR, which is evidently the resultant of FI and F2. Draw MK parallel to AB. Then
since OM is equal to AD in magnitude and in direction and MR is equal to BE in magnitude and direction, it follows that the triangles OMK and ADFi are equal, and the triangles MKR and BTE are equal. Hence the resultant OR is equal to FI + F2, and its line of action is a line through the point 0 parallel to the lines of action of FI and F2.
A similar proof can be given for the case of unequal parallel forces acting in opposite directions. Both results may be combined into the following theorem.
is parallel to the forces and equal to their algebraic sum and cuts a line joining their points of application into segments, the lengths of which are inversely proportional to the magnitudes of the forces.
135. Moment of a Force. The moment of a force with respect to a point, called the center of moments, is the product of the magnitude of the force and the perpendicular distance, called the arm, from the point to the line of action of the force.
Geometrically the moment of a force is represented by twice the area of a triangle whose base is the line representing the given force and whose vertex is the center of moments.
The moment of a force in a given plane with respect to a line perpendicular to that plane is the moment of the force with respect to the foot of that perpendicular. The line is called the axis of moments.
of moments.
136. Composition of Moments. The algebraic sum of the moments of any two forces with respect to any point of their plane is equal to the moment of their resultant with respect to the same point.
the forces are not parallel.
PROOF. Let OP, OQ be two forces acting at 0, and OR their resultant; and let A be any point in the plane about
We exclude the case in which the forces are equal and opposite.
Suppose that two forces P and Q act on the body at the points A and B, Fig. 85. From any point 0, draw OACB perpendicular to the lines of action of the forces. Let OA = p, AC = x. Then by § 134, CB = Px/Q. Taking moments about 0 we find
If P and Q are in opposite directions the proof is similar to the above and is left to the student. The proof in case P and Q are equal but opposite in direction is given in the following section.
magnitude and opposite in direction, is called a couple. The perpendicular distance between the lines of action of the forces is called the arm of the couple; and the plane containing the forces is called the plane of the couple.
The moment of a couple is the algebraic sum of the moments of its forces about any axis perpendicular to its plane and is equal to the product of either force and the length of the arm. For, let 0 be any axis, perpendicular to the plane of the couple, and OA and OB, the moment arms of the forces with respect to 0. Taking moments about 0, we have
The algebraic sum of the moments of the forces (written SAf) about any point is equal to the moment of the resultant. If the forces are in equilibrium, R = 0; therefore
where F represents the magnitude of a force. If the algebraic sum of the moments of the forces about any point is not zero, while the algebraic sum of the forces is zero, the resultant is a couple, and the body is not in equilibrium. Hence a necessary condition for equilibrium is that (15) 2F • x = 0,
SOLUTION. We have in this problem a balanced system of forces acting through the point A, namely, the load of 1000 Ibs. and the forces FI and F2 in the members AC and AB. Both AC and AB are subjected to a compression. Hence both members exert a thrust in the direction indictated by the arrows. The problem is to determine the magnitude of two unknown forces in a balanced system of three forces, the directions of the forces being known. This problem may be solved in any one of the three following ways.
sented by the sides of a triangle taken in order, Fig. 88. If the figure is drawn to scale the magnitudes of the unknown forces F\ and Ft may be obtained directly from the figure by measurement.
If the lengths of all of the members of the frame ABC are known or can be computed, we can obtain the magnitudes of FI and Ft by proportion, since the triangle ABC and the force triangle are similar.
THIRD METHOD. (Moments.) The sum of the moments of all the forces about any arbitrarily chosen point leads to one equation containing the unknowns. If we take the sum of the moments of all the forces about as many arbitrary points as there are unknowns then we will have as many equations as unknowns. The solution of these equations gives the magnitudes of the unknown forces. It is often advantageous to choose for the points about which moments are taken, points on the lines of action of the unknown forces, one on each line.
forces at A and D, Ex. 5.
8. Find the stresses in the members of the crane in Ex. 5, when the boom makes an angle of 15° with the horizontal.
10. Let F = 150 Ibs. (Fig. 93) and let the weight also be 150 Ibs What will be the largest angle between the inclined plane and the hori zontal at which the weight will not slip ? Ans. 30°.
11. Experiments indicate that a horse exerts a pull on his traces equal to about one-tenth of his weight, when the working day does not exceed 10 hours. The draft of a certain wagon is due to (a) axle friction = 5 Ibs. per 2000 Ib. load ; (6) gradient or hills ; (c) rolling draft depending on height of wheel, width of tire, condition of road-bed, etc.
12. What extra pull must a horse exert on his traces (assumed horizontal) if on a level road the wheel, 4 feet in diameter, strikes a stone 2 inches high, the load being 1000 Ibs. Ans. 436 Ibs.
13. A carriage wheel whose weight is W and whose radius is r rests on a level road. Show that any horizontal force acting through the center of the wheel greater than
in the rope. Ana. 625 Ibs.
16. A wire 90 feet long carries a weight of 25 Ibs. at each of its trisection points. When the wire is taut each weight is 5 feet below the horizontal line connecting the points of support. Find the tension in each segment of the wire. Ans. 150 ; 147.9 ; 150 Ibs.
21. If a horse exerts a pull on his traces equal to one-tenth of his weight, where should the single-tree for each of two horses weighing 1200 and 1600 Ibs., respectively, be fastened to a double-tree in order that each horse shall do his proper share of the work ?
22. The center clevis pin A, of a double-tree is a inches in front of the mid-point B, of the line connecting the end clevis pins C and D, which are b inches apart. If one horse is pulling c inches ahead of the other what fraction of the load L is each horse pulling, Fig. 101 ?
25. In Ex. 24 put a — 2, b — 40. Plot a curve using values of 9 as abscissas and values of the load pulled by one horse as ordinates. What can you say about the part of the load pulled by this horse as 0 increases ?
each horse if the total pull on the load is 362.88 Ibs.
27. The middle clevis pin A of a three-horse evener is a inches in front of the point B of the line connecting the end clevis pins C and D. The end clevis pins are b and 26 inches from the point B. Find what fractional part of the load is borne by the horse on the longer end when it is c inches behind the other horses.
3 3b
30. In Ex. 29 put a = 2, b = 25. Plot a curve using values of 0 as abscissas and fractional parts of the load pulled by the horse on the long end as ordinates. Discuss the problem.
SMALL ERRORS
139. Errors of Observation. Suppose that we measure the length of a building and record the result. Such a record is called a reading or an observation. Suppose that we measure the same length and record the reading on each of several successive days. On comparison it is likely we shall find that they do not exactly agree. What then is the true length? Whatever the actual length may be the difference between it and any observation of it is called an error of observation.
Suppose that we measure the length of a building with a tape whose smallest division is one foot. If the length is not a whole number of feet, we estimate by the eye the fraction of a foot left over. This estimate will almost certainly be in error. If we measure the same length with a tape divided to eighths of an inch, the end of the building may coincide with a division of the tape or we may have to estimate the fraction of an eighth. Subsequent readings are not likely to agree exactly with the first, and even if they do all agree we cannot be sure that we have the true length. Inattention and lack of precision of the observer, inexperience in using the measuring instrument, or the use of an instrument which is defective or out of adjustment, all tend to introduce errors. It is important to keep in mind that such errors are always present, in greater or less degree, in every set of observations.
If a is the recorded reading of a measurement of an unknown quantity u, a measure of the error in this reading is a positive number m, such that u lies between a — m and a + m. The actual error may be very much less than its measure m. For example if a rod of (unknown) length / be measured with a scale
It is evident that any number will be in error if it is derived by computation from other numbers which are inexact. Approximations are used in computations not only for recorded measurements but also in the case of irrational numbers, such as surds, most logarithms, trigonometric functions, TT, etc. We have 3-place, 5-place, 7-place, 10-place tables in order to secure the degree of accuracy desired in the computed result. In what follows it is shown how to find a measure of the error in a number computed by some of the simpler processes of arithmetic from given numbers the measures of whose errors are known.
140. Error in a Sum. Suppose that in measuring two quantities whose actual (and unknown) values are u and v, we make errors Aw and Av respectively, and record the readings a and b.
sum of their errors.
This result is readily extended to the sum of more than two readings. The error in the difference of two readings is never greater than the sum of their errors, though it may be greater than their difference.
EXAMPLE. Find the sum and difference of 46.8 ± 0.65 and 12.4 ± 0.15. Here the readings are 4.68, 12.4 and the measures of their errors are 0.65, 0.15 respectively. The measure of the error of their sum is
measure of their product divided by the square of the divisor.
EXAMPLE. Find the product and quotient of 12.4 ± 0.15 and 46.8 ± 0.65. By § 141, a measure of the error in the product is (12.4) (0.65) + (46. 8) (0.15) = 15.08 and the error in their quotient is measured by 15.08/(46.8)2 = 0.0069.
tient.
9. A line is measured with a chain (100 links each 1 ft. long). Afterwards, it is found that the chain is one foot too long. If the measured length was 10.36 chains, what is its true length if the error is assumed to be distributed through the chain? Ans. 10.4636 chains.
10. A line is measured with a 100-ft. tape and found to be 723.36 feet long. The tape is afterwards found to be 0.02 of a foot short. What is the true length of the line? Ans. 723.22 ft.
11. A certain steel tape is of standard length at 62° F. A tape will expand or contract sixty-five ten millionths of its length for each Fahrenheit degree change of temperature. A line is measured when the temperature of the tape is approximately 80° and found to be 323.56 feet long. What is its true length? Is it necessary to know the nominal or standard length of the tape to solve this problem?
between lots 2 and 3 extended, when the temperature is 40° F. Assuming that the map distances are correct, what lengths must be measured from 7th street and 8th street monuments respectively to locate the point A, the monuments being in the center lines of the streets? Ans. 160.02; 280.04
23. Compute 2.01 X 4.02 X 3.02 Draw a figure (parallelepiped) to represent this product and indicate 3 X 4 X .01; 2 X 3 X .02; 2 X 4 X .02; .01 X .02 X .02; 2X4X3. Ans. 24.4
143. Data derived from Measurements. The preceding results apply immediately to the case in which numbers obtained by measurement are stated without any accompanying indication of the probable error.
In such cases it is understood that the given figures are all reliable, i. e., that we stop writing decimal places as soon as they are doubtful. The last figure written down should be as accurate as is possible. Then the error will surely not be more than 5 in the next place past the last one actually written.
Thus, if a certain length is reported to be 2.54 ft., we would understand that the true length is not more than 2.545 ft., and not less than 2.535 ft. For if the true length is more than 2.545 ft., it should be given as 2.55 ft.; and so on.
It may happen that the last figure written down is 0. This means that that place is reliable. Thus, to say that a given length is 2.4 ft. means that the true length is between 2.35 ft. and 2.45 ft. But to say that a given length is 2.40 ft. means that the true length is between 2.395 ft. and 2.405 ft.
by actual measurement, to be 2.54 ft. and 6.24 ft., respectively.
Since the error in writing 2.54 ft. may be as great as .005, we must write for the length of this side (2.54 ± .005) ft. Likewise, we must write for the other side (6.24 ± .005) ft. Hence, by the rule of § 141, the error in the product may be as large as
1. Assuming that the numbers stated below are the results of measurements, and that each of them is stated to the nearest figure in the last place, find the required answer and state it so that it also is correct to the nearest figure in the last place you give, or else to within a stated limit of possible error.
4. Suppose that the dimensions of a bin are measured roughly to the nearest foot, and that they are 8 ft. by 4 ft. by 3 ft. How large may the volume actually be? How small may it be?
Ans. 118.1 cu. ft., 65.6 cu. ft.
5. The floor of a room is found by measurement to be 22 ft. X 15 ft., each dimension being to the nearest foot. How should the area be stated? Ans. 330 ± 18 sq. ft., or 300 sq. ft.
foot, express the volume of the room.
144. Error in a Square. If a is an observed value of an unknown quantity u, then it follows directly from § 141 that a measure of the error in w2 is approximately
sin a = sin (a ± Aa) = sin a cos Aa ± cos a sin Aa. Now if Aa is small, cos Aa is nearly equal to 1, and sin Aa is nearly equal to Aa. Whence we have, approximately, sin a •= sin a ± cos a • Aa,
and the smaller Aa is, the better the approximation. Hence, a measure of the error in the sine of an angle is the error in the reading (expressed in radians) multiplied by the cosine of the reading.
147. Computation of Error from Tables. This will be illustrated by an example. To find sin (36° 40' ± 10') we look in a table of sines and find sin 36° 50' = .5995, sin 36° 40' = .5972, sin 36° 30' = .5948 ; the difference between the first and second is .0023 and that between the second and third is .0024. Choosing the larger we write sin (36° 40' ± 10') = .5972 ± .0024.
for regularly spaced values of the argument. For example, a measure of the error in log u = log (o ± Aw) is the greater of the differences log (a + Aw) — log a and log a — log (a — Aw). Thus to find log (17.4 ± 0.7) we look up in the table log 16.7 = 1.2227, log 17.4 = 1.2405, log 18.1 = 1.2577. The larger difference is 0.0178 and we write
log (17.4 ± 0.7) = 1.2405 ± 0.0178 148. Errors in Computed Parts of Triangles, applications, e.g. in surveying, the given parts of triangles are subject to errors of measurement and consequently the computed parts are also in error. Suppose the base AB of the triangle ABC in Fig. 103 is 23.4 ± 0.02, the side AC = 15.6 ± 0.04, and the angle A = 32° 30' ± 10'. Then the altitude
Again, the area is given by the following computation.
Area = £(23.4 ± 0.02) (8.382 ± 0.06) = 98.069 ± 0.786. Similarly a measure of the error in any computed part of a triangle may be found by the foregoing principles of this chapter.
Calculate the error and the per cent, error of the square in each of the following numbers. Where no estimate of the error is expressed the error is supposed to be not greater than 5 in the next place past the last one written (§ 143).
19. By applying twice the formula for the error of the .square root of a ± Aa, show that the error of the fourth root of a ± Aa is Aa/4a. Find the error in the fourth root of 256 ± 1. Ans. 0.001
29. The formula for index of refraction is m = sin i/sin r, where i denotes the angle of incidence, and r the angle of refraction. If i = 50° and r = 40°, each subject to an error of 1%, what is m, and what its actual and percentage error?
is A = Vs(s - a)(s - b)(s — c) where s = \(a + b + c). A triangular field is measured with a chain that is afterwards found to be one link too long. The sides as measured are 6 chains, 4 chains, and 3 chains respectively. What is the computed area, and what is the true area?
32. Show that the erroneous area of a field, determined from measurements with an erroneous tape, will be to the true area as the square of the nominal length of the tape is to the square of its true length.
34. The acceleration of gravity as determined by an Atwood's machine is given by the formula: g = 2s /I2. Find approximately the error due to small errors in observing s and t.
35. A right circular cylinder has an altitude 12 ft. and the radius of its base is 3 ft. Find the change in its volume (a) by increasing the altitude by 0.1 ft., and (6) the radius by 0.01 ft. (c) By increasing each simultaneously. Ans. (a) 2.83; (6) 3.02; (c) 5.85
Show that AT IT = %Al/l — %Ag/g and hence a small positive error of k per cent, in observing I will increase the computed time by k/2%, and a small positive error of k'% m the value of g will decrease the computed time by k'/2 per cent.
where Wi is the weight of the body in air, w2 is the weight of a sinker in water, and w3 is the weight in water of the body with sinker attached. Determine the specific gravity of a body and the probable error if
39. To determine the contents of a silo I measure the inside diameter and height in feet and inches and find D = 8 ft. 2 in., h = 21 ft. 6 in. Find the error in the computed contents if there are errors AD = ± 0.4 in., A/i = 0.3 in. in the measured dimensions. Ans. 2.22 cu. ft.
40. My neighbor wants to buy the wheat from one of my bins. The measurements are: length = 12 feet; width = 6 feet; depth of wheat in bin = 8 ft. I make a mistake however of 1 /4 inch in measuring each 2 feet of linear measure. Find the error of contents in cubic inches. Find the error in bushels if 2150.4 cu. in. make 1 bushel. A more accurate value is 2150.42 Find the error due to using 2150.4 instead of 2150.42 Find the error if 2150 is used.
41. I decide to sell to a neighbor by measurement my corn in the crib. I measure with a yard stick placing my thumb to mark the end of the yard and holding my thumb in place proceed to measure beyond it thus making an error of 1/2 inch. My measurements are length = 30 ft. 3 in.; width = 11 ft. 9 in.; height 13 ft. 6 in. Find the error in cubic inches due to my method of measuring.
CONIC SECTIONS
149. Derivation. The circle, the ellipse, the parabola, and the hyperbola, are curves which can be cut out of a right circular conical surface by planes passing through it in various directions. For this reason, they are called also conic sections. Being plane curves, however, they can be defined and studied as the locus of a point moving in a plane under certain conditions.
in which the coefficients are real numbers and a, 6, c, are not all zero. The equation of the circle which we have obtained is of this form and has always 6 = 0 and a = c. Conversely, the special equation of the second degree
is the equation of a circle or of no locus. To show this we have only to complete the square of the terms in x and of the terms in y. This process will reduce it to the form of (1) § 150, as is shown in the next paragraph.
152. Determination of Center and Radius. When the equation of a circle is given, the center and radius can be found by transposing the constant term to the right and completing the square of the terms in x and also of the terms in y.
This shows that the given equation is satisfied by the point (3/5, 2/3) and by no other point in the plane. This case may be looked upon as the limiting case of a circle whose center is at (3/5, 2/3), and whose radius is zero.
2. Write the equation of a circle of radius 6 when the origin is (a) at the highest point of the circle ; (6) at the lowest point ; (c) at the leftmost point ; (d) at the rightmost point ; (e) when the origin divides the horizontal diameter from left to right in the ratio 1/3.
4. Show that if the coefficients of x2 and y2 in the equation of a circle are each + 1, the coordinates of the center can be found by taking negative one-half the coefficient of x and negative one-half the coefficient of y.
by the process of Ex. 4.
(a) x2 + y2 - 4x - 6y + 9 = 0. (d) x2 + y2 - 2x + 4y + 1 = 0. (6) x2 + y2 + 6x + 4y + 9 = 0. (e) x2 + y2 - 3x + 5y + 3 = 0. (c) x2 + ?/ - 4y = 0. (/) 2x2 + 2y2 + 4x - 6y + 1 =0.
6. The value of the polynomial P = x2 + y2 — 2x — 4y + 3 at any point of the xy-plane is found by substituting the coordinates of the point for r and y in P. Thus at (3, 2), P = 2. Show that all points at which P is positive lie outside a certain circle, and all points at which P is negative lie inside the same circle. With respect to this circle, where are the points (0, 1), (1, 2), (2, 3), (4, 5), (0, 3), (1, 4), (2, 2)?
153. Translation of Axes. Given a pair of axes OX and 0 Y, a curve C, and its equation in terms of the coordinates x = OA and y = AP. (Fig. 105.) Move the origin to the
These equations are true no matter which way nor how far the origin is moved if the new axes are parallel to the old ones. These values substituted in the old equation of the curve, give the new equation. Hence, to find the new equation, substitute in the old equation, in the place of x, the new x plus the abscissa of the new origin and in the place of y, the new y plus the ordinate of the new origin.
called the directrix.
155. Equation of the Parabola. Let F be the focus and RS the directrix of a parabola. (Fig. 106.) Draw FD perpendicular to the directrix. The
We have now proved that every point on the parabola satisfies the equation (5). It follows that the parabola has no points on the left of the y-axis, for negative values of x cannot satisfy the equation (5).
The parabola is symmetric with respect to the line through its focus perpendicular to its directrix. This line is called the axis of the parabola. The point where the parabola crosses its axis is called its vertex. The chord through the focus perpendicular to the axis of the parabola is called its latus rectum. Let the student show that the length of the latus rectum is 4p.
The parabola y2 = 4px crosses every horizontal line exactly once, and every vertical line to the right of the 7/-axis twice, once above and once below the z-axis. The farther the vertical line is to the right, the farther from the z-axis does the curve cut it.
The position of each of these curves should be related to its equation as follows: yz = 4px is a parabola tangent to the y-axis at the origin, having its focus on the x-axis to the right. The student should make similar statements concerning equations (6), (7), and (8).
represents a parabola whose vertex is at (h, k) and whose axis is either horizontal (equation (9)) or vertical (equation (10)). For, on translating the axes to this point they reduce to one of the types (5), (6), (7), or (8) considered above. In particular, the equation
represents a parabola whose axis is vertical. It is concave up or down according as a is positive or negative, and the vertex, focus, and directrix can be found by completing the square of the terms in x and reducing it to the form (10).
is j above the vertex.
Similarly, the equation x = ay2 -\-by-\-c can be reduced to the type (9) by completing the square of the terms in y, and from this a sketch of the parabola can be made.
6. The cable of a suspension bridge assumes the shape of a parabola if the weight of the suspended roadbed (together with that of the cables) is uniformly distributed horizontally. Suppose the towers of a bridge 240 ft. long are 60 ft. high and the lowest point of the cables is 20 ft. above the roadway. Find the vertical distances from the roadway to the cables at intervals of 20 ft.
7. An arch in the form of a parabolic curve is 29 ft. across the bottom and the highest point is 8 ft. above the horizontal. What is the length of a beam placed horizontally across it, 4 ft. from the top?
Similarly the point A' to the left of F' such that A'O = a, is a point on the ellipse. The points A and A' are called the vertices. The segment A' A is called the major axis of the ellipse.
on the axes.
Let a denote the acute angle OFB. Then cos a is called the eccentricity of the ellipse, and is denoted by e. It is evident that e = OF JO A. Hence, from the right triangle OFB, we have
The numbers a, b, e, are positive, a > 6, e < 1, &2/a2 = 1 — e2. The coordinates of the foci are (ae, o) and (— ae, 0). The focal distances of any point on the ellipse are a — ex and a + ex, respectively.
The equation shows that the curve is symmetric with respect to the x-axis and also with respect to the ?/-axis. It follows that the curve is symmetric with respect to the origin. It is only necessary to plot that part of the curve which lies in the first quadrant to determine the shape of the whole curve, which is as shown in Fig. 111.
The ellipse can be drawn by the continuous motion of a pencil point by means of a pair of tacks set at the foci and a loop of string around them as shown in Fig. 112. This1 is the best method of tracing an ellipse on a drawing board. It can be used to lay out an ellipse of any desired size on the ground. Let the student show that the length of the loop of string is 2o(l + e).
shows that any ordinate of the ellipse is to the corresponding ordinate of the circle as b is to a. The diameter of this circle (20) is the major axis of the ellipse. For this reason, the circle (20) is called the major auxiliary circle, or simply the auxiliary circle. The points where any ordinate cuts the ellipse and the auxiliary circle are called corresponding points.
159. Area of an Ellipse. Since the horizontal dimensions of the ellipse and its auxiliary circle are the same, and since their vertical dimensions are in the ratio b : a, we have
160. Projection. If a circle of radius a be drawn on a plane making an angle a with the horizontal plane, then the vertical projection of this circle on the horizontal plane is an ellipse whose semi-major axis is a and whose semi-minor axis is a cos a, since its ordinates are to the corresponding ordinates of the circle as a cos a is to a.
EXAMPLE 1. Reduce the equation of the ellipse 3x2 + 4y2 = 48 to standard form; find a, b, and c, the coordinates of the foci, the focal distances to the point (2, 3), and the area of the ellipse.
Dividing through by 48, we find
Then, by comparison with (19), we have o2 = 16 and b2 = 12, whence a = 4 and b = 2V3. From (13) we find e = £; hence ae = 2. It follows that the foci are (—2, 0) and (2, 0). The right-hand focal distance to (2, 3) is a — ex = 3 and the left-hand focal distance is a + ex = 5. The area is irab = 87rA/3 = 43.53 +
1. Find the semi-axes, the eccentricity, locate the foci, and find the focal distances to any point (x, y) on the curve; construct the rectangle on the axes, and sketch the curve:
2. In each of the following cases find the values of a, b, e, if they are not given. Locate the foci, and write the equation of the ellipse. Construct the rectangle on the axes and sketch the curve.
7. A circular window in the south wall of a building is 4 ft. in diameter. Light from the sun passes through the window and falls on the floor. Find the area of the bright spot at noon, when the angle of elevation of the sun is (a) 60°, (6) 45°, (c) 30°.
8. An ellipse whose semi-axes are 10 and 9 is in a horizontal position. Through what angle must it be rotated about its minor axis hi order that its projection on a horizontal plane shall be a circle.
in a manner analogous to those for the ellipse.
By an analysis similar to that given in § 157 for the ellipse, it can be shown that the equation of the hyperbola whose semitransverse axis is a, whose semi-conjugate axis is 6, whose center is at the origin and whose foci are on the cc-axis, is
The curve consists of two branches and is symmetric with respect to both axes and with respect to the origin, as shown in Fig. 115. The quantities a, b, and e (= sec a), are positive, a = b, e > 1, 62/a2 = e2 — 1; the coordinates of the foci are (ae, o) and ( — ae, o) ; the focal distances to a point on the right branch are ex — a and ex + a, and to a point on the left branch, the negatives of these. The diagonals OC and OC",
The rectangle on the axes is a square, the eccentricity is sec 45° = V2, and the asymptotes are the two perpendicular lines y = x and y = — x. This is called a rectangular or equilateral hyperbola. It plays a role among hyperbolas analogous to that played by the circle among ellipses.
The product of the distances of any point on an equilateral hyperbola to its asymptotes is constant. For the distance to the asymptote y = x is (x — y) cos 45°, and the distance to the asymptote y = .— x is (x + y) cos 45°; hence the product of these distances is a2 cos2 45° = £a2.
To sketch the curve, lay off OA = 3, OB = 4, Fig. 117, construct the rectangle on the axes, locate the foci by circumscribing a circle about this rectangle. Sketch in the curve free hand in four parts beginning each time at a vertex, using the asymptotes as guides, the curve approaching them in distance and direction.
1. Find the semi-axes, the eccentricity, the coordinates of the foci, the focal distances to the point indicated, the equations of the asymptotes; construct the rectangle on the axes and the asymptotes, and sketch each of the following hyperbolas.
and the constant is 2a.
5. Find the locus of a point where two sounds emitted simultaneously at intervals one second apart at two points 2,000 ft. apart are heard at the same time, the speed of sound in air being 1,090 ft. per second.
6. On a level plain the crack of a rifle and the thud of the bullet on the target are heard at the same instant. The hearer must be on a certain curve; find its equation. (Take the origin midway between the marksman and the target.)
163. Intersection of Loci. If a point lies on a curve, its coordinates must satisfy the equation of that curve. Conversely, any pair of values of x and y which satisfy an equation determines a point on the locus of that equation. If the same pair of values of x and y satisfies two equations, it locates a point which is common to the two curves, i. e., a point of intersection. Hence, to find the points of intersection of two curves, solve their equations simultaneously to find all their common solutions.
164. Straight Line and Conic. The equations of the circle, parabola, ellipse, and hyperbola, are all of the second degree in x and y. Conversely, it can be shown that every such equation represents a conic section, if it represents any curve at all. Given a straight line and a circle we know that one of three things will happen, 1) there may be two intersections, 2) there may be no intersection, or 3) there may be only one point in common and then the line is a tangent. The same three cases occur with the intersections of a straight line with any conic section.*
When we solve simultaneously the equation of a straight line with the equation of a conic, we may begin by substituting the value of y from the first equation in the second. The result is a quadratic equation in x. This quadratic equation (§§ 32, 33), (27) Ax2 + Ex + C = 0
EXAMPLE. Of the three parallel
lines 8z - 9y = 20, 8z - Qy = 30, and 8x — 9y = 25, the first cuts the ellipse 4x2 + 9?/2 = 25 in two points (5/2, 0) and (7/10, - 8/5), the second does not intersect it at all, and the third intersects it at (2, — 1) only, i. e. it is tangent at that point.
1. Show that one of the three lines 4x + 25 = Wy, 4x + 27 = lOy, 4x + 21 = lOy, intersects the parabola y2 = 4x in two points, another is tangent, and the third does not intersect it at all.
165. Tangent and Normal. Focal Properties. The
equation of the tangent to a conic can be found by the principles of § 164 if the slope of the tangent is known, or if the coordinates of one point on the tangent are known. This given point may be the point of contact or some other point through which the tangent is to pass.
By (13) § 61, the slope of the required tangent is 3, and by (11) § 59, y = 3x + b is parallel to it no matter what value b has. Proceeding to find the points where this line intersects the parabola we are led to the quadratic equation,
We' first verify that the given point is in fact on the ellipse. Then by (10) § 59, y — 3 = m (x — 2) is the equation of a line through (2, 3) no matter what value m has. Solving this simultaneously with the equation of the ellipse we get the quadratic equation,
We learn in Physics that light is reflected by a mirror in such a way that the angle of incidence is equal to the angle of reflection. Hence, a ray of light emanating from a source at the focus and
striking the parabola at any point, will be reflected parallel to the axis. This is the principle of parabolic reflectors which are extensively used for head lights. It is easily seen that if the light be moved slightly beyond the focus, the reflected rays will tend to illuminate the axis.
The normal at any point of an ellipse bisects the angle between the focal radii to that point, Fig. 120. It follows that rays of light, or sound, emanating from one focus F, will after reflection by the ellipse, converge at the other focus F". Hence the name focus. This is the principle of whispering galleries.
14. The ground plan of an auditorium is elliptic in shape. The extreme length is 2,725 ft. and the width is 2,180 ft. By what path will a sound made at one focus arrive first at the other focus, i. e., directly or by reflection from the walls? How much sooner if sound travels 1,090 ft. per second?
166. Intersection of Conies. Simultaneous Quadratics.
Two conies intersect, in general, in four points. Since their equations are of the second degree in x and y, this corresponds to the fact that two quadratics in x and y have, in general, four solutions. In some cases these solutions are not all real, or there may be less than four so that the conies represented intersect in less than four points.
As shown in Fig. 121a, the hyperbola x2 — y- = 5 intersects the ellipse x2 + 4?/2 = 25 in the four points (3, 2), (- 3, 2), (-3, - 2), and (3, - 2). The parabola 4x2 = Qy cuts the same ellipse only in (3, 2) and (— 3, 2), as shown in Fig. 1216.
We find that the solutions of (a) are (3, 2) and ( — 3, — 2) ; and those of (6) are (3, — 2) and (— 3, 2). It is easy to verify that these are all solutions of the given equations by actual substitution.
Eliminate x2 and solve for y2. This gives y2 = 4, whence y = ± 2. Then eliminate y2 and solve for x2. This gives x2 = 9, whence x = ± 3. Verify that (3, 2), (- 3, 2), (-3, - 2), (3, - 2), are all solutions of the given equations.
Hence the values of x and y are x = ± 3 or ± 2, y = ± 3, or ± 2. Testing these values in the given equations we verify that (3, 2), (2, 3) (—2, — 3), (—3, — 2), are solutions.
VARIATION
167. Function and Variables. One of the most common scientific problems is to investigate the causes or effects of certain changes. The change or variation of one quantity in the problem is produced or caused by changes in other variable quantities and is said to depend upon, or be a function of these variables. Thus the growth of a plant depends on the amount of certain constituents in the soil, upon the temperature and humidity of the soil and of the atmosphere, upon the intensity of the light, and doubtless upon several other variables. The volume of gas contained in an elastic bag depends on the pressure and the temperature. The circumference of a circle depends only on the radius.
To study the effect of any one variable upon a function of two or more variables, we try to arrange conditions so that all the other variables of the problem shall remain constant, while this one varies. Thus we keep the temperature of a gas constant to find the effect on the volume of a change of the pressure. To study the effect of carbonate of lime on the growth of alfalfa, we arrange a series of plats of soil so that they shall have all the other constituents the same, and all be subject to the same conditions of light, heat, and moisture, but differ from plat to plat by known amounts of pulverized limestone.
The precise form of the relation between a function and its variables is often very complicated and difficult or impossible to obtain. Often, the best that can be done is to record the results of experiments and to study these records to deduce
processes of nature.
168. Direct Variation. One of the simplest relations that can exist between two variables is called direct variation. When the ratio of two variables is constant, each is said to vary directly as the other.
170. Joint Variation. When a function z depends upon two variables x and y, in such a manner that z varies as the product xy, i. e., z = kxy, then z is said to vary jointly as x and y. Thus, the area of a rectangle varies jointly as the length and the
breadth. This definition may be extended to functions of three or more variables. A function /, depending upon several variables x, y, • - • , z, is said to vary jointly as x and y, • • • , and z, when it varies as their product, i. e., / = kx-y • - - z. Thus, simple interest varies jointly as the principal, and the rate, and the time.
It is evident that if one variable z depends on two other variables x and y, and if z varies as x when y is constant, and z varies as y when x is constant, then z varies jointly as x and y when x and y vary simultaneously. Thus, the area of a triangle varies as the altitude when the base is constant and varies as the base when the altitude is constant; therefore the area varies jointly as the base and the altitude.
This principle is readily extended to functions of three or more variables. Thus, simple interest varies as the principal when rate and time are constant, as the rate when principal and time are constant, and as the time when principal and rate are constant; therefore simple interest varies jointly as the principal, the rate, and the time.
know one other point on the line, i. e., one pair of simultaneous values of x and y; and values of y corresponding to any given values of x, can be read directly from the graph. Then k is the difference of two values of y divided by the difference of the corresponding values of x (§ 58).
Plotting the point (2, 1) and drawing the line OP we have the graph of the relation between x and y. From this we read off y = | when x = 1, y = 3i when x = 6|, etc. Fig. 122.
When y varies inversely as x, the graph of their relation xy = k is a rectangular hyperbola asymptotic to the x and y axes. Here again one point is sufficient to determine k and fix the curve.
172. Determination of the Constant. By substituting in an equation of variation a set of simultaneous values of the variables, the constant of variation can be determined.
EXAMPLE 1. Given, y varies as x and y = 8 when x = 10. We may write y = kx, as in § 168. Substituting x = 10 and y = 8, we find 8 = ft- 10. From this equation, we can find k by dividing both sides by 10. This gives k = 4/5. Hence we have y = (4/5)x.
EXAMPLE 2. A light is 24 inches above the center of a table. The illumination I at any point P of the surface of the table varies directly as the cosine of the angle of incidence, i, of the ray LP, and also •p ^24 inversely as the square of the distance LP = x to the
light. If the illumination at C is 10, what is it at any point P of a circle of radius 18 inches about C? SOLUTION. The illumination 7 at any point is
of their mean distances from the sun.
4. With the statement of Ex. 3 (c) find the heat generated by a mass of 8 kilograms striking the sun with a velocity of 500 miles per second if a body weighing one kilogram and moving with a velocity of 380 miles per second on striking the sun produces 45,000,000 calories of heat.
5. The simple interest due on P dollars varies jointly as the amount P, the rate, and the time. If $1000 yields $30 interest in six months find the interest on $1200 for eight months at 7%.
(b) Mercury has a diameter of 3000 miles and is 36 million miles from the Sun. The Earth has a diameter of 8000 miles and is 93 million miles from the Sun. Compare the amounts of heat they receive.
30 units. Ans. 165 yrs.
8. The amount of heat received on a surface of given size varies inversely as the distance from the source. One body is twice as far as another from the source. Compare the amounts of heat received.
of the velocity. Discuss the effect of doubling the velocity.
10. The maximum load P that a rectangular beam supported at one end will hold without breaking varies directly as the breadth, the square of the depth and inversely as the length. A beam 4" X 2" X 10' supports 300 pounds. What load will the same beam support when placed on edge?
11. The deflection y in a rectangular beam supported at the ends and loaded in the middle varies directly as the cube of the length, inversely as the breadth, and inversely as the cube of the depth. A beam 6 inches wide, 8 inches deep, 15 feet long, supporting 1000 Ibs., has a deflection of \ inch at the middle. Find the deflection in a beam 4 inches wide, 4 inches deep, 10 feet long, supporting 800 Ibs.
19. Similar figures vary in area as the squares of their like dimensions. A new grindstone is 48 inches in diameter. How large is it in diameter when one-fourth of it is ground away?
of each side of the hexagon is doubled.
22. Similar solids vary in volume as the cubes of their like dimensions. A water pail that is 10 inches across the top holds 12 quarts. Find the volume of a similar pail that is 12 inches across the top.
23. Using the rectangular pack, 432 apples 2 inches in diameter can be put in a box 12 X 12 X 24. How many 3 inch apples can be packed in the same box? How many 4 inch apples? Ans. 128; 54.
24. If a lever with a weight at each end is balanced on a fulcrum, the distances of the two weights from the fulcrum are inversely proportional to the weights. If 2 men of weights 160 Ibs. and 190 Ibs. respectively are balanced on the ends of a 10 foot stick, what is the length from the fulcrum to each end? Ans. 4^ ft.; 5f ft.
26. Two persons of the same build are similar in shape; their weights should vary as the cube of their heights. A man 5| ft. tall weighs 150 Ibs. Find the weight of a man of the same build and 6 feet tall.
28. The size of a stone carried by a swiftly flowing stream varies as the 6th power of the speed of the water. If the speed of a stream is doubled, what effect does it have on its carrying power? What effect if trebled?
EMPIRICAL EQUATIONS
173. Empirical Formulas. In practice, the relations between quantities are usually not known in advance, but are to be found, if possible, from pairs of numerical values of the quantities discovered from experiment.
In order to determine the relation between these quantities it is useful to first plot the corresponding pairs of values upon cross-section paper, and draw a smooth curve through the plotted points. If the curve so drawn resembles closely one of the following types of curves:
we assume that the relation connecting the quantities is the corresponding equation of the above set and it remains to determine the constants of the equation.
to be in error, errors will occur in the computed values of the coefficients. The curve represented by the final equation will not in general pass through the points representing the observed data. Some of these points will be on one side and some on the other. All will be near the curve.
174. Computation of the Coefficients in the Assumed Formula. In case the plotted points appear to be upon a straight line, a parabola, or a curve of the nth degree, the corresponding equation is assumed and we proceed to determine the coefficients by a method which is illustrated in the following example.
Two equations are necessary and sufficient for the determination of the two unknowns a and b. In general if we have more equations than unknowns the equations are not consistent. That is, the values of a and b as determined from the first two equations are not the same as those obtained from the last two, or from the second and third, etc. Our problem then is to derive from the given set two equations such that the values of a and b obtained therefrom when used as coefficients in the assumed equation will give us a straight line which fits closely the points plotted from the observed data. There are in common use a number of ways of doing this.
FIRST METHOD. Multiply each equation in turn by the coefficient of a in that equation and add. This gives one equation containing a and b. Multiply each equation in turn by the coefficient of b in that equation and add. This gives a second equation containing a and b. Using the data in (8) above we find in this way the following equations : 53764a + 4246 = 20744,
SECOND METHOD. When on plotting it is clear that a straight line is the best fitting curve, draw a straight line among the points so that about half are above and half below. The y coordinate of the intersection of this line with the y-axis can then be read directly from the graph and gives the value of 6 in the equation y = ax + b. Measure the angle a that this line makes with the z-axis and then a = tan a.
should be assumed, use n + 1 points evenly distributed along the curve. This method gives us always the same number of equations as there are unknown coefficients to be determined.
4. In an experiment to determine the coefficient of friction between two surfaces (oak) the following values of F were required to give steady motion to a load W. Plot F and W on squared paper, and find M where M = F/W. [CASTLE] Ans. M = 3.302
11. A restaurant keeper finds that if he has G guests a day his total daily expenditure is E dollars, and his total daily receipts are R dollars. The following numbers are averages, obtained from the books
Find the simple algebraic laws which seem to connect E and R with G. [R = mG; E = aG + b.] What are the meanings of m, a, and fe? Below what value of G does the business cease to be profitable?
12. The following statistics (taken from Bulletin 110, part 1 of the Bureau of Animal Industry, U. S. Dept. of Agriculture) give the changes in average egg production between 1899 and 1907:
142.77
With the actual and modified averages in hand we may inquire: what has been the general trend of the mean annual egg production during the period covered by the investigation? The clearest answer to this question may be obtained by plotting the figures in the fourth and sixth columns of the above table, and then striking through each
of the two zigzag lines so obtained the best fitting straight line, as determined by the method of least squares. The equations of the two straight lines are as follows:
meaning of the constant term in each equation.
175. Substitution. If on plotting the given values of x and y the plotted points are seen to be approximately on a branch of a rectangular hyperbola with vertical and horizontal asymptotes we assume a relation of the form
There are many curves which resemble closely the curve given by equation (14), but whose equation is somewhat different. In order to determine whether (14) is the best equation to represent the plotted data, obtain from the figure an approximate value of a. In many cases a = 0. Make the substitution l/(x — a) = u and plot the new points (u, y). If these are approximately upon a straight line then
assume.
If on plotting the observed values of x and y the plotted points appear to be on a parabola with axis parallel to one of the axes and vertex on that axis then call that axis the ?/-axis and assume (15) y = a + bx2. '
where u = xz. As a check that (15) is the correct form to assume plot pairs of values of u and y. If these points appear to be on a straight line then equation (15) is the correct form to assume.
1. The following data on the relation of temperature to insect life gives the number of days at a given temperature to complete a given stage of development and is taken from Technical Bulletin, No. 7, Dec. 1913 of the New Hampshire College Ag. Exp. Station, each case the plotted points are on a curve of the type
The term developmental zero is used to designate that point at which an insect may be kept, theoretically at least, without change for an indefinite period. The developmental zero for the insect and stage approximates the point where the reciprocal curve (calculated from the time factor) intersects the temperature axis. (6 = developmental zero.)
3. The pressure p, measured in centimeters of mercury, and the volume v, measured in cubic centimeters, of a gas kept at constant temperature, were found to be as follows.
5. If a body slides down an inclined plane, the distance «, in feet, that it moves is connected with the time t, in seconds, after it starts by an equation of the form s = kP. Find the best value of k consistent with the following data.
If the values of x and y are tabulated in columns, and their logarithms X and Y are looked up and written in parallel columns opposite, then the points (X, Y) should lie on a straight line to justify the assumption of equation (16). And if they do lie fairly on a line, its slope and y-intercept determine the constants m and b of equation (16). This can often be done graphically from the drawing with sufficient accuracy, but if greater accuracy is required they can be determined from the data by least squares.
and determine k and log c by the method of least squares.
177. Logarithmic Paper. Paper, called logarithmic paper, may be bought that is ruled in lines whose distances, horizontally and vertically, from a point 0 are proportional to the logarithms of the numbers 1, 2, 3, etc.
Such paper may be used instead of actually looking up the logarithms in a table. For if the given values be plotted on this new paper, the resulting "figure is identically the same as that obtained by plotting the logarithms of the given values on ordinary squared paper.
2. The amount of water A, in cu. ft., that will flow per minute through 100 feet of pipe of diameter d, in inches, with an initial pressure of 50 Ibs. per sq. in., is as follows:
14. Plot a curve from the following data, find its equation, and estimate the pressure for a velocity of 110 miles per hour. The pressure is given in pounds per square foot of cross section of the first car in a train of ten, and the velocity in miles per hour.
THE PROGRESSIONS
178. Arithmetic Progression. A sequence of numbers in which each term differs from the preceding one by the same number is called an arithmetic progression (denoted by A. P.). The common difference is that number which must be added to any term to obtain the next one.
is not an A. P.
179. Notation. The following symbols are commonly used to denote five important numbers, called elements, which are considered in connection with arithmetic progressions.
Given any three of the elements a, n, I, d, s, either of the other two can be found by substituting in (1) or (2) and solving. If n is to be found, the given elements must be such that the formula will be satisfied by a positive integral value of n.
The value n = — 3 is inadmissible. Substituting n = 10 in (3), we obtain a = — 3. Hence n = 10, a = — 3, and the arithmetic progression is - 3, - 2\, - 2, - 1|, - 1, - i, 0, i, 1, H.
181. Arithmetic Means. The terms of an arithmetic progression between the first and last terms are called arithmetic means. Between any two numbers as many arithmetic means as desired can be inserted. To do this we can use equation (1) to compute the common difference d, for a and / are known and n is two more than the number of terms to be inserted. Then the required means are. a + d, a + 2d, etc.
The problem of inserting one arithmetic mean between two numbers is the same as the problem of finding the average of two numbers. If m is the average of o and b, then
m is called the arithmetic mean of a and 6.
EXAMPLE. Insert 4 arithmetic means between 7 and 20. Here a = 7, I = 20, n = 6. Substituting these values in (1), we have 20 = 7 + 5-d, whence d = 2|. Hence, the required means are 9$, 12i, 14f, 17|.
30. I desire to close up one side of crib 12 feet 4 inches high, with 6 inch boards. I have just 21 boards. I desire to leave a 1 inch crack at top and bottom. How far apart must I place the boards to have them equally spaced? Ans. 1 inch.
32. The population of a certain town has made a net gain of the same number of people each year for the last 30 years. In 1893 it was 1523 ; in 1906 it was 2212. What was it in 1890 ? in 1902 ? in 1916 ? Predict the population for 1925.
33. What will it cost to erect the steel work of a 20 story building at $3000 for the first story and $250 more for each succeeding story than for the one below? Ans. $107500.
34. I drop a rock over a cliff 400 ft high. How long before I hear it strike bottom if it falls 16 ft. the 1st second, 48 ft. the 2d second, 80 ft. the 3d second, etc., and sound travels 1090 ft. per second in air?
Ans. 5f sec. nearly.
35. A ball rolling down an incline goes 2 ft. the first second and 6 ft., 10 ft., 14 ft., respectively in the next three seconds, starting from rest. How far will it roll in 15 seconds? Ans. 450 ft.
37. A farmer is building a fence along one side of a quarter section. The post holes are dug one rod apart and the posts are piled at the first. How far will he walk to distribute them one at a time and return to set the first one? Ans. 20| miles.
increased by 1, the result is a perfect square.
182. Geometric Progression. A sequence of numbers in which each term may be found by multiplying the preceding term by the same number is called a geometric progression (denoted by G. P.). The constant multiplier is called the common ratio. Thus
is a G. P. in which the common ratio is 5.
The elements of a geometric progression are the first term a or oi, the number of terms n, the last or nth term / or an, and the sum s or sn of the first n terms.
184. Geometric Means. If three positive numbers are in geometric progression the middle one is said to be the geometric mean of the other two. It is easy to see that the geometric mean of two numbers is the square root of their product. Thus 3 is the geometric mean of 2| and 4.
mediate terms are said to be geometric means between the first and last terms. We can insert as many geometric means as we wish between any two positive numbers. To do this we use equation (4), § 183, to compute r; a, I, and n being known. Then the desired means are ar, ar2, ar3, etc.
EXAMPLE. Insert three geometric means between 4 and 16. Since 16 is to be the 5th term we have a = 4. ar4 = 16, whence r4 = 4 and r = V2 ; hence the five terms are 4, 4V2, 8, 8 V2, 16.
26. It takes 32 nails to shoe a horse. A blacksmith agrees to drive them as follows : 2 cents for the first, 4 cents for the second, 8 cents for the third, etc. What is the total cost? Ans. $85,899,345.90
29. A man promises to pay $10,000 at the end of 5 yr. What amount must be invested each year at 6 % compound interest so that at the end of the time the debt can be paid?
34. A potato cuts into 4 parts for planting, each piece produces 5 good sized potatoes, 80 of which make a bushel. If I plant each year all that I raised the preceding year, how many bushels of potatoes will I have at the end of the fifth year? How much are they worth at $4.00 per bu. ? Ans. $160,000.
35. One kernel of corn planted produces a stalk with 2 ears with 16 rows each, 50 kernels to the row. Suppose 100 ears make a bushel and that I plant each year one-half of all that I raised the preceding year and that one-half of the kernels grew and produced. How many
36. I have one sow. Let us suppose that the average litter of pigs is 6, sexes equally distributed, and that I keep all of the sows each year but sell all the others. How many sows in the sixth generation? How many pigs will have been sold after I have disposed of 1 /2 of the last or 5th litter? Am. 243; 363.
37. The common housefly matures and incubates a new litter every 3 weeks. There are approximately 200 to a litter evenly distributed as to sex. What will be the number of descendents of one female fly in 12 weeks? Ans. 2 X 108.
38. Grasshoppers hatch yearly a brood of 100 evenly distributed as to sex. Assuming that none are destroyed, what will be the number of descendants of one female grasshopper at the end of 5 years? 6 years?
39. The apple aphis matures and incubates in 10 days. The progeny, all females, are 5 in number. The female propagates 5 each day for 30 days. What will be the number of descendants of one female at the end of 30 days?
41. Find the amount of money that could profitably be expended for an overcoat which lasts 5 years provided it saved an annual doctor bill of $5, money being worth 6% compound interest.
42. The effective heritage contributed by each generation and by each separate ancestor according to the law of ancestral heredity as stated by Galton is shown in the following table from Davenport.
Compute the effective contribution of the last 20 generations. The number of ancestors involved in the 20th generation backward and the total number of ancestors involved. The effective contribution of each ancestor in the 20th generation backward.
185. Infinite Geometric Series. A geometric progression can be extended to as many terms as we please, since on multiplying any term by the common ratio we obtain the next one. Any series which has no last term and can be indefinitely extended is called an infinite series.
Suppose the terms of a geometric series are all positive. If we begin at the first and add term after term the sum always increases. If r > 1, this sum becomes infinite, i.e., if we choose a positive number N no matter how large it is possible to add terms enough that the sum will exceed N. If however r < 1, the case is quite different. The sum does not become infinite ; it converges to a limit, i.e., it is possible to find a number L such that the sum will exceed any number whatever less than L, but it will never reach L. For example the sum obtained by adding terms of the geometric series
in which r = -|, will never reach 1.5, but terms enough can be added to make the sum exceed any number less than 1.5. If, e.g., we wish to make the sum greater than 1.49, five terms are sufficient.
A geometric series in which r < 1 is called a decreasing geometric series. The limit to which the sum of the first n terms of a decreasing geometric series converges is a/(\ — r), i.e., the first term divided by one minus the ratio.
Now as we add more and more terms, the n in this formula gets larger and larger, a and r remain fixed. Since r < 1, it follows that r2 < r, r3 < r2, etc., and rn converges to zero when n is taken larger and larger. Therefore the second term on the right converges to zero, and sn converges to a/(l — r). This
EXAMPLE. The repeating decimal .666 ••• can be written thus .6 + .06 + .006 + •••. It is therefore an infinite geometric series whose first term is .6 and whose common ratio is .1. Hence
186. Definitions. Suppose you take out a life insurance policy on which you agree to pay a premium of $100 at the end of each year for 10 years. Such an annual payment of money for a stated time is termed an annuity. Instead of paying $100 a year you may prefer to pay $24 at the end of every three months or $206 at the end of every two years. In any case the stated amount paid at the end of equal intervals of time is called an annuity.
Suppose the stated sums are not paid when due and that after the lapse of say 5 years you desire to pay off your indebtedness with interest compounded. The sum due is called the amount of the annuity for the five years.
Suppose you buy a house and agree to pay $1000 at the end of each year for 4 years. This is an annuity. An equivalent cash price at the time of sale is called the present value of the annuity.
be proportional to this.
The first payment of one dollar made at the end of the first year will bear interest for n — 1 years, and at the end of the period the amount due will be (1 + t)™"1. The second payment will bear interest for n — 2 years and will increase to (1 + i)n~2. The next to the last payment will bear interest for one year and will increase to 1 + i. The last payment will be one dollar and it will bear no interest. The total amount S^, due at the end of n years is therefore
In this geometric progression the first term is 1, the last term is (1 + i)n~S and the ratio is 1 + i. Substituting these values in the formula (5) § 183 for the sum of a geometric progression, we find
189. Partial Payments. Suppose that the payments instead of being made at the end of each year are made at the end of each pth part of a year for n years. Consider an annuity of one dollar.
The payment to be made at each payment period is l/p. The first payment will bear interest for n — \/p years. The second payment will bear interest for n — 2/p years, and so on. The next to the last payment will bear interest for l/p years. The
As shown in § 145 for the square root, the pth root of 1 + i is nearly equal to 1 + i/p. In fact it is customary in computing the amount of one dollar at interest compounded p times a year, to use 1 + i/p instead of Vl + i- See § 217. If this approximate value be used in formula (2), the right member reduces to
190. Given the Amount of an Annuity to find the Annuity. Let the annual payment be x. The first payment made one year from the beginning of the term of the annuity will bear interest for n — 1 years and will increase to x(l + i)n~l. Likewise, the second will increase to x(l + i}n~~, the third to (1 + z')"~3> and so on, while the last payment x will bear no interest. If the sum of the amounts due at the end of n years is $1, we have
x[(\ + t)"-1 + (1 + i)"-2 + •" + (1 + i) + i] = 1. The expression within the square brackets is a geometric progression of n terms with ratio (1 + i} ; hence, by (5), § 183, we have
4. A city decides to pave some of its streets. For this purpose bonds, bearing 6% interest, to the amount of $50,000 are issued. The bonds are due in 10 years. What sum must be collected yearly in taxes and invested at 6% to pay off the bonds when due?
191. Present Value of an Annuity. The present value of one dollar due in one year is (1 + *)-1, one dollar due in two years is (1 + i)~2>
1. A man buys a farm, agreeing to pay $1500 cash and $1500 at the end of each year for three years. What would be the equivalent cash value of the farm if money is worth 6%?
2. A man buys a farm, agreeing to pay $2000 cash and $2000 at the end of each year for ten years. What would be the equivalent cash value of the farm if money is worth 6%?
3. A contractor performs a piece of work for a city and takes bonds in payment. The bonds do not bear interest, and are payable in 10 equal annual installments of $2000, the first payment to be made one year from date. Money being worth 6%, payable annually, what is the cash value of the bonds on the date of issue ?
192. Cost of an Annuity. A man desires to provide for his family, in event of his death, an annuity of $5000 a year for 20 years. What amount must he set aside in his will to provide for this annuity, assuming that money is worth 6%.
5. A man with $10,000 pays it into a life insurance company which agrees to pay him or his heirs a stated sum each year for 20 years. What is the yearly payment, money being worth 4%?
193. Perpetuities. In the previous problems treated in this chapter the payments continued over a fixed number of years and then stopped. The annual amount expended for repairs on a gravel road does not stop at the end of a given period, but continues forever. Such payments constitute an endless annuity, which is called a perpetuity. Other examples are the annual repairs on a house, taxes, annual wage for a flag man, annual pay of a section gang. The amount of an annuity would evidently increase indefinitely as time went on. The present value of a perpetuity, however, has a definite meaning. The present value of a perpetuity is a sum which put at interest at the given rate will produce the specified annual income forever. Denote by V the present value of the perpetuity and by P the annual payment. Then
This is an infinite geometric progression whose first term is P(l + i)-" and whose ratio is (1 + t)"". Hence, by (7), § 185, the present value of the perpetuity is
5. The life of a certain farming implement costing $100 is 6 yrs. Find what sum must be set aside to provide for an indefinite number of renewals, money being worth 4%.
6. The life of a University building costing $100,000 is 100 years. A man desires to will the University enough money to erect the building and to provide for an indefinite number of renewals. How much must he leave the institution?
194. Meaning of an Average. In referring to a group of individuals, a detailed statement of the height of each would take considerable time, when large numbers are involved. In comparing two or more groups, such a mass of detail might fail to leave a definite impression as to their relative heights. What is needed is a single number, between that of the shortest and that of the tallest, which is representative of the group with respect to the character measured. Such an intermediate number is called an average.
The idea of an average is in use in everyday affairs. We hear mentioned frequently such expressions as the average rainfall, the average weight of a bunch of hogs, the average yield of wheat per acre for a county or state, the average wage, the average length of ears of corn, the average increase in population, etc. Often these expressions are used with only an indefinite idea as to what is really meant.
195. Arithmetic Average. The arithmetic average is the
* The authors of this book are indebted for many ideas in this Chapter and for some of its methods to an Appendix by H. L. RIETZ to E. DAVENPORT, Principles of Breeding, Ginn and Co. Some use has been made also of ZIZEK, Statistical Averages, Henry Holt and Co. ; PEARSON, Grammar of Science; BOWLEY, Elements of Statistics; and SECRIST, Introduction to Statistical Methods, Macmillan/
number of measurements
Thus, if we measure seven ears of corn and find their lengths to be 6, 7, 8, 9, 10, 11, 12 inches, the arithmetic average of their lengths is 9 inches. Again, the arithmetic average of 6, 7, 8, 12, 12 is 9. This example shows that the arithmetic average gives no indication of the distribution of the items and that there may be no item whose measurement coincides with the average. However, it is influenced by each of the items, and it is easily understood and computed. It should seldom be used except in conjunction with other forms of averages. When used alone it should be for descriptive purposes only.
In the simple case mentioned above, the weighted arithmetic average gives the same result as the arithmetic average. Its chief advantage is that it facilitates computations. For example the average length of the ears of corn whose individual lengths are 6, 7, 8, 12, 12 can be found as follows :
several times. Thus, in measurements, an item that is known to be particularly trustworthy may be counted doubly or triply. In such cases, the weighted average differs from the arithmetic average.
197. The Median. If we arrange the numbers representing the measurements of the items in order of magnitude, the middle number is called the median. Thus, the median length of the ears of corn whose lengths are 6, 7, 8, 12, 12 inches is 8 inches. In case there are an even number of items the median is midway between the two middle terms. Thus if the lengths of four ears of corn are 6, 7, 9, 10 inches, the median length is 8 inches. There is no ear of this length among those measured.
The median is often used because it is so easily found. Like the arithmetic mean, it gives no indication of the distribution. It can be used even when a numerical measure is not attached to the various items. For example, ears of corn can be arranged in order of length without knowing the numerical length of any ear ; clerks can be ranked in order of excellence ; shades of gray may be arranged with respect to darkness of color ; etc. The median is the central one of a group and is unaffected by the relative order of the other members of the group. Thus it is used when the primary interest is in the central members.
198. The Mode. In measuring the items of a given set it may happen that some one measurement occurs more frequently than any other. This measurement is called the mode. Thus, the modal length of six ears of corn whose lengths are 6, 7, 8, 12, 12, 13 inches is 12 inches. A set of measurements may have more than one mode. Thus in a given factory there might be few men who received $2 per day, a large number who received $3, a small number who received $4, and a large number who received $5, while few received more than $5. There would then be two modes for wages, namely $3, and $5.
If a curve be plotted using measurements as abscissas and the number of items corresponding to each frequency as ordinates, the mode corresponds to the maximum ordinate or ordinates. (See § 225.)
Unlike the arithmetic average, and the median, the mode is always the value of one individual measurement. Extreme measurements have no effect upon it.
In measuring heights of men we might place all those over 4.5 and under 5.5 feet at 5 feet. For this distribution the mode would necessarily fall at one of the integers. If we arrange the heights in three-inch intervals the mode might not appear as an integer, although it would be near the mode first obtained. Thus it is seen that the mode depends upon the grouping of the measurements.
The existence of a mode shows the existence of a type. It is the mode that we have in mind when we speak of the average height of a three-year-old apple tree, the average price of land, or the average interest rate.
199. The Geometric Average. The geometric mean of two positive numbers has been defined in § 184. By analogy we may define the geometric average of n positive numbers as the nth root of their product.
If a growing tree doubles its diameter in 20 years what is its annual percentage rate of increase ? It is not 5%, for an increase of 5% a year would give the following diameters at the end of the 1st, 2d, 3d, . . ., 20th year
of about 3|% will double anything in 20 years. The geometric average is used in many practical affairs. Knowing the average rate of growth of a city in the past the geometric average is used to predict its future growth. When a new school building is being designed, for example, it should be made large enough to meet the future growth of the community as shown by this geometric average.
200. Conclusion. Given a set of items numerically measured or not, we should first determine whether or not the data is such as to warrant any kind of an average. Then the decision whether one or another kind of average is to be employed depends upon the use to which the result is to be put. If the data is not complete, the arithmetic average cannot be used. If we desire to characterize a type in such a case, we may find the mode, for which the data need not be complete.
Frequently it is best to make use of more than one kind of average in describing a distribution. It must be remembered that any average at best conveys only a general notion and never contains as much information as the detailed items which it represents.
2. Determine in the following cases which average is meant : mean daily temperature ; average student ; average price of butter ; average of a flock with respect to egg production ; average salary for all of the teachers of a state ; average number of bushels of corn per acre for a state or nation ; normal rainfall ; average number of pigs per litter ; average number of hours of sunshine per day ; average speed of train between two stops ; average wind velocity ; mean annual rainfall ; average sized apple ; average price of oranges when arranged according to sizes ; average date of the last killing frost in the spring ; average price of land per acre in a given locality ; average gain in weight per day of a hog.
3. What kind of an average is meant in each of the following cases : one fly lays on an average 120 eggs; 63% of the food of bobolinks is insects ; every sparrow on the farm eats j oz. of weed seed every day ; the average gas bill is $2 per month ; the average price received for lots in a subdivision was $800; repairs, taxes, and insurance on a house average $100 per year ; the average amount of material for a dress pattern is 8 yards, 36 inches wide ; a college graduate earns on an average $1125 a year, while the average yearly earnings of a day laborer, who has no more than completed the elementary school, is $475.
4. Suppose that we consider 5 millionaires and 1000 persons who are in poverty. Find the arithmetic average, the median, and the mode of the wealth of this group. Which best portrays conditions?
5. In the Christian Herald for March 10, 1915, p. 237, it is stated that : "The average salary of ministers of all denominations is $663. The few large salaries bring up the average." Which average is used here? Is it the best to portray conditions? Is the result too high or too low to represent conditions properly?
11. If in the last 20 years the number of deaths in the U. S. due to consumption has increased 50%, find the annual rate of increase, using the geometric average. Ans. 2%.
13. Find the average (arithmetic) word, sentence, and paragraph length, of some one of the writings of Longfellow, Holmes, Whittier, Poe ; of some short story ; of some newspaper article.
persons born on the same day are 5,023,371. If the total number of -years to be lived is divided by the number of persons the quotient will be the average number of future years to be lived by each person. What kind of an average is this ? What average age does it give ?
PERMUTATIONS AND COMBINATIONS
201. Introduction. In how many ways can I make a selection of two men to do a day's work if there are 3 men available for the forenoon and 4 for the afternoon? Having hired one man for the forenoon, I can hire any one of 4 for the afternoon, and since this is true for each of the three, there are 3 X 4 = 12 ways of making the selection. This reasoning is general ; that is, it does not depend upon the special properties of the numbers 3 and 4. Hence we see that if there are p ways of doing a first act, and if corresponding to each of these p ways there are q ways of doing a second act, then there are pq ways of doing the sequence of two acts in that order.
more than two acts and we may say,
If there are p ways of doing a first act; and if after this has been done in any one of these p ways there are q ways of doing a second act; etc.; and if after all but the last of the sequence have been done there are r ways of doing the last act, then all the acts of the sequence can be done in the given order in pq ••• r ways.
3. There are 6 routes from Chicago to Seattle, 4 from Seattle to Portland, 3 from Portland to San Francisco. How many ways are there of going from Chicago to San Francisco via Seattle and Portland?
202. Combinations and Permutations. A group of things selected from a larger group is called a combination. The things which constitute the group are called elements. Two combinations are alike if each contain all the elements of the other irrespective of the order in which they appear. Two combinations are different if either contains at least one element not in the other.
A permutation of the elements of a group or combination, or simply a permutation, is any arrangement of these elements. Two permutations are alike if, and only if, they have the same elements in the same order. Thus, eat, tea, and ate are the same combination of three letters a, e, t ; but they are different permutations of these three letters.
203. Number of Permutations. The number of permutations of three elements taken all at a time is 6, as may be seen by writing them down and counting them :
If the number of elements is large the process of counting is tedious. It is possible to derive general formulas for the number of permutations of any number of elements by which the number can be easily computed.
204. Permutations of n Things. A rule for the number of permutations of n things taken all at a time is easily deduced by means of the principle of § 201 . We have n elements and n places to fill. We may think of a row of cells numbered from 1 to n.
The first cell can be filled in n different ways and after it has been filled the second cell can be filled in n — 1 ways. Therefore the first two can be filled in n(n — 1) ways. When they have been filled in any one of these possible ways the third cell can be filled in (n — 2) ways. Therefore the first three cells 2an be filled in n(n — l}(n — 2) ways. Continuing thus we see that the first k cells (k < n) can be filled in n(n — l}(n — 2) ••• (n — k + 1) ways, and that all the n cells can be filled in n(n — l}(n — 2) -"2 • 1 ways. This product of all the natural numbers from 1 to n is called factorial n, and is denoted by n ! or \n. Thus, 2 ! = 2, 3 ! = 6, 4 ! = 24, 10 ! = 3,628,800. Therefore,
can be put into 10 stanchions in 3,628,800 ways.
By the same reasoning the number of permutations of n things k at a time (k ^ n) is the number of ways that k cells can be filled from n things. The symbol nPt is used to denote this number. Then, as shown above,
To remember this formula, note that the first factor is n and the number of factors is k. Thus B^3 = 5 • 4 • 3 = 60. The number of ways in which 4 stanchions can be filled out of a herd of 10 cows is 10P4 = 10 • 9 • 8 • 7 = 5040. In this notation we should write for the number of permutations of n things all at a time
the number of distinguishable permutations is less than n \ For example, the number of distinct permutations that can be made out of the 7 letters of the word reserve is not 7 ! The number of permutations of the 7 characters ri, ei, s, 62, r2, v, 63 is indeed 7 ! ; but when the subscripts are dropped the permutations TI e\ s e^rzv 63 and r^ £2 s e3 r\ v e\ become identical.
Let x be the number of different permutations of the letters of the word reserve. For each of these x there will be 2 ! permutations of the characters r\ e s e r<z v e and for each of these x • 2 ! there will be 3 ! permutations of the characters r\ c\s cz rz v 63, making x • 2 ! 3 ! in all. It follows that
This reasoning can be extended to show that the number of distinguishable permutations of n elements of which p are alike, q others are alike, etc., •••, r others are alike, is equal to
3. Find the number of permutations of the letters in each of the following words : (a) degree, (6) natural, (c) Indiana, (d) Mississippi, (e) Connecticut, (/) Kansas, (g) Pennsylvania, (h) Philadelphia, (i) Onondaga, (j) Cincinnati.
12. How large a vocabulary could be formed with 9 letters, no repetitions being allowed? How many with ten? How many with twenty-six? (There are about 100,000 words in Webster's dictionary. The average man has a vocabulary of less than 5000 words.)
206. Combination of n Things k at a Time. The symbol nCk or (2) is used to denote the number of different combinations (§ 202) that can be made from n elements taken k at a time.
A combination of k elements can be arranged into k ! permutations of these elements. That is, there are k I times as many permutations as there are combinations of k elements taken all at a time. Whence
This is what we should expect when we think that the numbers of ways that k things can be selected from a group of n must be the same as the number of ways that n — k can be rejected.
in which the coefficients have the following values:
Ci = 01 + a2 + «3 + • • • + an. The number of these terms is n. C2 = Oi02 + • • • aian + aza3 +'•••+ a3a4 + • • • + an-i«n.
This is known as the binomial expansion, or binomial formula.
208. Binomial Theorem. If x and y are any real (or imaginary) numbers and if n is a positive integer, then the binomial formula (2) is valid. The following observations will be of value.
by 1 in each succeeding term.
(3) The coefficient of the first term is 1, that of the second term is n. The coefficient of any term can be found from the next preceding term by multiplying the coefficient by the exponent of x and dividing by one more than the exponent of y.
209. Binomial Coefficients. The coefficients in the binomial expansion are called binomial coefficients. Their values are given in the following table for a few values of n. This table is called Pascal's triangle.
its right, the sum is the number under the latter.
210. Sum of Binomial Coefficients. A great many uses for binomial coefficients and a great many relations among them have been discovered. Two of these are as follows.
211. Use of the Binomial Theorem. In expanding a binomial with a given numerical exponent, the student is urged to find thq successive coefficients by using the statement (3) § 208, and not by substitution in a formula. This is illustrated in the following examples.
equal to the same numbered one, counted from the last.
212. Selected Terms. To select a particular term in the expansion of a binomial without computing the preceding terms, we can use the formula for the (r + l)th term, namely,
213. The Binomial Series. The binomial theorem and the symbols nCr for the number of combinations of n things taken r at a time, have no meaning except when n and r are positive integers. On the other hand we know that such expressions as
If we should expand a binomial whose exponent is not a positive integer by the binomial theorem (that is form the coefficients and exponents by the same rules as though the exponent were a positive integer), we should get a non-terminating series of terms. For example,
Now it is shown in advanced courses in mathematics, that this binomial series is actually valid, provided the numerical value of the first term of the binomial is greater than the numerical value of the second term. It is then valid, in the sense that if we begin at the first and add term after term, the more terms we take the nearer the sum approaches to the true value sought and that, by taking terms enough, the sum which we are computing will approximate the true value as nearly as we please.
214. Mendel's Law.* An Austrian monk by the name of Mendel planted some sweet peas of different colors in the garden of the monastery. These blossomed and produced seed. This seed was gathered and planted the following year. The flowers produced the second summer contained all of the colors of the first summer, but other colors were present. By observing and counting the number of flowers of each color Mendel discovered the law which bears his name. In its simplest form it may be explained as follows.
Suppose a bed of sweet peas with blossoms half of which are red and half of which are white. Fertilization of the flowers by wind and insects will take place without selection. That is, pollen from a white flower is equally likely to fertilize a red or a white flower. If pollen from a white flower fertilizes a white
LAWS OF HEREDITY
flower the seed produced is of pure stock and will produce pure white flowers the following year. Such flowers let us denote by W2. If pollen from a white flower fertilizes a red flower, or vice versa, the seed produced will be mixed stock and the following year will show its mixed character by producing flowers which are neither red nor white but some intermediate shade. Such flowers let us denote by RW. The symbol R2 is now self-explanatory. On counting the flowers which are pure white, mixed, and red, we would discover their numbers to be approximately in the ratio 1:2: 1. These are the coefficients in the expansion of (R + W)2. This is what one might have expected beforehand, as is seen from the adjoined table. Observe that there are twice as many flowers of mixed color as of either of the pure colors.
215. Successive Generations. Let R* denote the result of fertilizing R2 with R2 ; RSW denote the result of fertilizing R2 with RW, and so on. Then the results of indiscriminate fertilization of the flowers will be shown in the second generation, but in the third year, as given in the following table.
Result of mixing : R* + 4RW + 6RW2 + 4RW3 + W* Observe that the result in the second generation of mixing is the binomial expansion of (R + W)4.
216. Mixing of Three Colors. Make a table, as above, but for three colors. Suppose the third color to be blue (B). Then a complete expression for the effect, in the first generation after mixing, is the following :
Mendel's law of heredity, as illustrated above by the distribution of color in the successive generations of plants, applies to other transmissible characters in both plants and animals. That this distribution follows the mathematical laws of the binomial formula is due to the fact that each individual plant or animal inherits the characteristics of two parents, and hence the number two and its mathematical properties have their analogies in the laws of biology.
3. A farmer buys two different kinds of thoroughbred chickens but allows them to mix freely. How many different kinds of chickens will he have at the end of (a) the first, (6) the second, (c) the third year of hatching? Ans. (a) 3, (6) 5, (c) 9.
7. I plant 8 sweet pea seeds — 4 red, 4 white. Each seed produces 16 flowers — each flower matures 2 seeds which germinate and grow the following season. Find the total number of flowers, the proportion and number of the different kinds of flowers, in the (a) first, (6) second, and (c) third generations.
THE COMPOUND INTEREST LAW
217. Compound Interest. Suppose one dollar to be loaned at compound interest at r% per annum payable annually. The interest i, due at the end of the first year, is r/100. The amount due is 1 + i- If interest is payable semiannually the amount due at the end of the first half year is 1 + i/2* If the interest is payable quarterly the amount due at the end of the first quarter is 1 + i/4.
In general terms if the interest is payable p times a year at r% per annum compound, the amounts due on a principal of one dollar at the end of the 1st, 2d, • • •, pth period are respectively,
p times a year on a principal of P dollars is given by the formula
* The amount of one dollar for n years compound interest at r% payable annually is (1 + i)n. If a settlement is made between two interest dates there is some divergence of practice in computing the interest for the fractional part of a year. The amount of one dollar for the pth part of a year by analogy to (1 + t)w would be (1 +t) l/p = Vl + i, but 1 + - is often used instead. When, however, by the terms of the note the interest is payable p times a year, and is to be compounded, it is clear that the amounts due at the end of 1, 2, •••, n periods are
218. Continuous Compounding. The larger p is the shorter the interval between the successive interest paying dates. As p increases without bound this interval approaches zero ; i.e. we can take p large enough to make this interval as small as we please. In the limit interest is said to be compounded continuously. While this state is never realized in financial affairs it is closely approximated. For example, large retail stores sell goods over the counter very nearly continuously and continuously replenish their stock.
zero, the quantity (1 + x)x converges to a certain number between 2 and 3. This number is the base of the natural or Napierian system of logarithms and is usually denoted by e. To five decimal places c = 2.71828. It can be shown that the following steps are justifiable, although the proof will not be given here. By the Binomial Formula,
Scientific investigations reveal many examples of quantities whose rate of increase (or decrease) varies as the magnitude of the quantity itself. For example, the number of bacteria in a favorable medium, or the growth of an organic body by cell multiplication ; again the rate of decrease in atmospheric pressure in ascending a mountain is proportional to the pressure, and the rate of change in the volume of a gas expanding against resistance varies as the volume. The proverbial phrases, the rich grow richer, the poor poorer; nothing succeeds like success; a stitch in time saves nine; are expressions in popular language which show a recognition of this law in crude form.*
In general terms if y and x are two varying quantities such that the rate of change in y (as regards a change in x) is known to vary directly as y itself, then they are connected by an equation of the form
in which c and k are constants.
EXAMPLE. Suppose that atmospheric pressure at the earth's surface is 15 Ibs. per square inch and that it is 10 Ibs. per square inch at a height of 12,000 ft. If now it be assumed that the rate of decrease in the pressure is proportional to the pressure, we have from equation (4)
by means of which the pressure at any height h can be computed.
This example illustrates the method of solving similar problems which fall under the compound interest law. We assume an equation of the form of (4) and determine the constants c and k by substituting in known pairs of values of x and y. Having determined the constants we insert them in the assumed formula which is then in form to give the value of y corresponding to any value whatever of x.
1. Do you see any relation between the growth of plants, or the increase in population, and the compound interest law? Is the relation exact? What circumstances tend to limit its application?
3. The population of the state of Washington was 349,400 in 1890 and in 1900 it was 518,100. Assume the relation P = ceT, where P = population, T = time in years after 1890, and predict the population for 1910.
4. Using the data of Ex. 3, find the average annual rate of increase from 1890 to 1900. Assuming the same average rate to be maintained for the next 10 years, predict the population for 19^0.
5. When heated, a metal rod increases in length according to the compound interest law. If a rod is 40 ft. long at 0° C., and 40.8 ft. long at 100° C., find (a) its length at 300° C; (&) at what. temperature its length will be 41 ft. 6 in. Ans. (a) 42.448 ; (&) 185°.8
6. The rate of increase in the tension of a belt is proportional to the tension as the distance changes from the point where the belt leaves the driven pulley. If the tension = 24 Ibs. at the driven pulley, and 32 Ibs. ten feet away, what is it six feet away? fAns. 28.52
7. Assuming that the rate of increase in the number of bacteria in a given quantity of milk varies as the number present, if there are 10,000 at 6 A.M., 60,000 at 9 A.M., how many will there be at 2 P.M.? At 3 P.M.? At 6 P.M.? Ans. 2 P.M., 1,188,700.
8. In the process of inversion of raw sugar, the rate of change is proportional to the amount of raw sugar remaining. If after 10 hours 1000 Ibs. of raw sugar has been reduced to 800 Ibs., how much raw sugar will remain at the end of 24 hours? Ans. 586 Ibs.
PROBABILITY
219. Definition of Probability. // an event can happen in h ways, and fail in f ways, the total number of ways in which the event can happen and fail is h +/. Then h/(h +/) is said to be the probability that the event will happen, andf/(h-\-f) is said to be the probability that the event will fail.
For example, suppose we have a box containing 4 red marbles and 5 white ones. Let us determine the chance of drawing a red marble the first time. This event can happen in 4 ways, and fail in 5 ways, while the total number of ways in which the event can happen and fail is nine. Then by the preceding definition the probability of drawing a red marble is 4/9, and the probability of not drawing a red marble is 5/9. Observe that one of these things is certain to happen. The measure of this certainty is the sum of the probabilities of the separate events. This sum is 1 . Hence, if p is the probability that an event will happen, the probability q that it will not happen is 1 — p.
220. Statistical Probability. In a throw of a penny, before the event takes place, there is no reason to suspect that heads are more likely to turn up than tails. The probability of a man's making a safe hit in a game of baseball, and that of not making a safe hit are not equal. Here the individuality of the batter enters and before the event takes place, if the batter
is unknown, we have nothing on which to make an estimate. If the batter is known, our estimate is based on his past performance and this, unlike a throw of dice, depends upon the particular individual at bat. If out of the last 60 times at bat, he has made a safe hit 20 times, then we say that the probability of his making a safe hit this time at bat is 1/3.
Again what is the probability that a man aged 70 will die within the next year? Clearly this depends upon the individual, his present state of health, his habits, etc. In this case, however, we can construct a measure of his probability of dying which is independent of these personal elements. From the American Experience Mortality Table (see Tables, p. 329), we find that out of 38,569 persons living at age 70, within the year 2,391 die. Hence the probability that a man aged 70 will die within the year is 2,391 -4- 38,569.
1. According to the mortality table (p. 329) it appears that of 100,000 persons at the age of 10, only 5,485 reach the age of 85. What is the probability that a child aged 10 will reach the age of 85?
ticket out of a total of 1000 tickets. Ans. 30 cents.
222. Mutually Exclusive Events . Two events are said to be mutually exclusive if the occurrence of one of them precludes the occurrence of the other. For example, in a race between A, B, and C, if A wins, B and C do not win.
// the probabilities of the mutually exclusive events E\, E%, •••, En are p\, pz, •••, pn, then the probability that some one will occur is the sum of the probabilities of the separate events.
The meaning will be made clear by means of the following illustration. A bag contains 3 red, 4 white, and 5 blue balls. What is the probability that in a first draw we obtain a red or a white ball? Then from the definition of probability the chance of drawing a red ball or a white ball is 7/12. But the probability of drawing a red ball is 3/12 and that of drawing a white ball is 4/12 and (3/12) + (4/12) = 7/12.
223. Dependent Events. Events are said to be dependent if the occurrence of one influences the occurrence of the other. // the probability of a first event is p\ ; and if after this has happened the probability of a second event is p^; etc., ••• ; and if after all those have happened the probability of an nth event is pn ; then 'the probability that all of the events will happen in the given order is Pi, P2 "• pn.
For, if the first event can happen in hi ways and can fail in /i ways ; and if after this has happened the second can happen in h% ways and can fail in fa ways ; etc., ••• ; and if after these have hap-
pened the nth event can happen in hn ways and can fail in /„ ways ; then they can all happen and fail in (hi + fi)(hz + f%) ••(hn + /») ways. Now all the events can happen together in the given order in hi A2 ••• hn ways. Then by the definition of probability the chance that all of the dependent events will take place in the given order is
(hi +fi)(h2 +/2) -. (hn +/„) hi +/! For after drawing one red ball and not replacing it the probability of drawing a red ball the second time is 2/4.
3. Suppose I enter 2 horses for a race and that the probabilities of their winning are respectively | and j. What is the probability that one or the other will win the race? Ans. 3/4.
4. Does Ex. 3 teach us anything with respect to diversified farming? Discuss the probability of crop failure of a single crop as compared with that of two or more different crops.
7. In a certain zone in times of war 23 out of 5000 ships are sunk by submarine in one week. What is the chance that a single vessel will cross the zone safely? What is the chance that all of 4 vessels which enter the zone at the same time will cross in safety ? What is the chance that of these 4 exactly 3 will cross in safety ? That at least 3 will cross in safety?
8. In certain branches of the army service 2% of the men are killed each year. Three brothers enlist in this branch of the service for a period of two years. Compute the probability that (a) all will survive, (b) exactly 2 will survive, (c) at least 2 will survive, (d) exactly one will survive, (e) at least one will survive, (/) none will survive.
13. Three horses are entered for a race. The published odds are 5 : 4 for A ; 3:2 against B ; 4:3 against C. Is it possible to place bets in such a way that I win some money no matter which horse wins ?
14. Suppose n horses entered for a race, and let the published odds be (a — 1) to 1 against the first ; (6 — 1) to 1 against the second, (c — 1) to 1 against the third and so on. A man bets (a — l)/a to I/a against the first; (b — l)/6 to 1/6 against the second, etc. Show that whatever horse wins his gains are represented algebraically by the formula
225. Frequency Distribution Curves.* A sample of 400 oats plants were taken from an experimental plot and measured as to height in centimeters with the following results : f
agrees with the grouping of the measurements as to height.
* In the remainder of this Chapter (§§ 225-231), the authors are indebted for many ideas to E. DAVENPORT, Principles of Breeding [Chapter XII and Appendix (H. L. HIETZ)]. Other books containing similar matter are JOHNSON, Theory of Errors and Method of Least Squares: WRIGHT AND HAYFORD, Adjustments of Observations; MERRIMAN, Textbook of Least Squares; WELD, Theory of Errors and Least Sqiiares; etc.
in Fig. 128.
The upper parts of these rectangles form an irregular curve made up of segments of straight lines. A smoother curve is obtained by connecting the middle points of the upper bases of these rectangles by segments of straight lines as shown by the dotted line in Fig. 128. Instead of the dotted line we may draw a smooth curve as near as possible to the middle points of the upper bases. Any curve drawn as nearly as possible through a series of plotted points representing a distribution with respect to a given character is called a frequency distribution curve.
Such curves are useful in presenting to the eye some of the features of a distribution. The type of character most frequent is represented by the mode (§ 198), which is the value of the abscissa corresponding to the highest point of the curve. The median measurement of the group (§ 197) is represented by the abscissa of that ordinate on either side of which there are equal areas under the curve. The arithmetic average (§ 195) is the abscissa of the center of gravity of the area under the curve.
Frequency distribution curves are plotted for a great variety of things, such as frequency distribution of people with respect to height, weight, or age ; grains of wheat with respect to weight ; alfalfa with respect to duration of bloom in days ; cherry trees with respect to earliness of bloom ; pigs with respect to size of litter; diphtheria with respect to time of year; women with respect to age of marriage ; etc.
226. Probability Curve. If a large number of measurements are made upon the same item, they will not in general agree. Let us plot as abscissas the measurements observed and as ordinates their relative frequencies. In most cases, the positive
and negative errors are equally likely to occur, and small errors are more numerous than large ones. The frequency curve for the observed data would then have its highest point at the true value of the measured magnitude, would be symmetric about an ordinate through this highest point, and would rapidly approach the axis of abscissas both to the right and left of this maximum ordinate. If we take the vertical through the highest point as an axis of y, then abscissas will represent errors of observation and ordinates will represent frequency of error.
in which cr is what we shall call the standard deviation, e = 2.71828 ••• the base of Napierian logarithms, n the number of observations, x the error of a reading, y the probability of an
of error.
While the theoretical curve (1) is symmetric, the curves obtained by plotting the results of statistical study are often not symmetric. However the formulas developed in this chapter for the symmetric case can be used for approximate results in the non-symmetric cases.
the mode.
The general theory will be explained by means of the data of § 225, which represents the measurements of the heights of 400 oat plants. From this data the average height of oat plant is 70.8 centimeters. Compute the deviation, D, of these plants from their average height. Multiply the square of each deviation by its corresponding frequency and add the results. We get 19,320. Divide by the sum, 400, of the frequencies. The quotient is 48.3. We next extract the square root since the deviations have all been squared in the above calculations. We get 6.95~, and this is called the standard deviation.
In general, to find the standard deviation,
Compute the deviation of each frequency from the arithmetic average. Multiply the square of each deviation by its corresponding frequency and add the results. Divide by the sum of thefrequenci.es. Extract the square root.
small, and the curve B represents the distribution when a is large.
For example, the two sets of numbers 7, 7, 8, 8, 8, 8, 9, 9 and 5, 6, 7, 8, 8, 9, 10, 11 have the same arithmetic mean. The second set, however, shows a greater tendency to vary from the arithmetic average (type) than does the first. This greater tendency to vary is shown by the larger value for cr for the second set. The values of a- are 0.706 and 1.87 respectively.
Again, suppose two men are shooting at a mark, and that we compute the standard deviation for each. The man for whom <r is smallest is said to be the more consistent shot.
228. Coefficient of Variability. A comparison of the standard deviations of two different groups conveys little information as to their respective tendencies to deviate from the arithmetic average. This is due to two causes : (1) the measurements may be in different units, as centimeters and grams, (2) one average may be much larger than the other, for example the average height of a group of men would be larger than the average length of ears of corn. We need then a measure of variability which is independent of the units used and takes into account the relative magnitudes of the means. Such a measure is the coefficient of variability, which is denoted by C and is determined by the formula,
229. Probable Error of a Single Measurement. Any individual measurement is likely to be in error. This error is approximately the difference between this measurement and the arithmetic average of all the measurements. Compute these errors for all the measurements, some positive, some negative. Give them all positive signs and arrange them in order of magnitude. The median of this list is called the probable error of a single measurement of the set and is denoted by Es. It is shown in the theory of probability that
230. Probable Error in the Arithmetic Average. Take a sample of 500 ears of corn from a crib. Compute the arithmetic average of their lengths. We use this to represent the mean length of all the ears in the crib. Quite likely it differs from their true arithmetic average. We now find by means of equation
(5) below, a number Em, called the probable error in the arithmetic average. This is a number such that it is equally likely whether or not the computed arithmetic average of the 500 ears selected lies between ra — Em and m + Em, where m denotes the (unknown) true arithmetic average for all the ears in the crib. In other words if a very large number of persons take a sample of ears and each computes an average length, then, in a sufficiently large number of cases, one half of these averages will be within the limits set and one half will be without. In treatises on probability it is shown that
many observations.
231. Probable Error in the Standard Deviation. Compute the standard deviation, § 227, of the lengths of 500 ears of corn from a crib. This will differ slightly from the true standard deviation <r, of the lengths of all the ears in the crib. Next find, by means of equation (6) below, the probable error Eay of the standard deviation. Then for a sufficiently large number of samples from the crib, the computed standard deviations will fall one half within the limits a- — E* and a- + Ey, and one half without. The formula for the probable error in the standard deviation is
Frequency. . . .
4. Compute from the following data the mode, the mean, the coefficient of variability, the standard deviation, the probable error in the mean, and the probable error in the standard deviation.
Draw the distribution curve.
5. The following table is taken from BULLETIN 110, PART 1, Bureau of Animal Husbandry, U. S. Dept. of Agriculture on "A BIOMETRICAL STUDY OF EGG PRODUCTION IN THE DOMESTIC FOWL" and shows the frequency distribution for hens in first-year egg production.
6. From Table I at the end of Chapter XIX compute for each weight (length) the mean, the median, and the mode for length (weight). Compute <r, C, E<r, Em, E, of weight (length) for each length (weight).
232. Meaning of Correlation. Whenever two quantities are so related that an increase in one of them produces or is accompanied by an increase in the other and the greater the increase in the one the greater the increase in the other, these quantities are said to be correlated positively. If an increase in one produces, or is accompanied by, a decrease in the other, they are said to be correlated negatively. If a change in one is not accompanied by any change in the other, there is no correlation, and the quantities are said to be unrelated. Perfect positive correlation is represented by the number + 1, perfect negative correlation by — 1, no correlation by zero. There is perfect positive correlation between the area of a rectangular field and its length, the extension of a spiral spring and the suspended load. There is perfect negative correlation between the pressure and volume of a perfect gas. No relation exists between the price of coal and the length of ears of corn.
There are quantities, common in everyday life, such that a change in one is not accompanied by a proportionate change in the other, but a given change in one is always accompanied by some change in the other. Such quantities are still said to be correlated. The degree of relationship may be anywhere between complete independence and complete dependence, that is
* Throughout this Chapter, the authors have consulted the following books, and are indebted to them for ideas: E. DAVENPORT, Principles of Breeding (Chap. XIII); ZIZEK, Statistical Averages; SECRIST, Introduction to Statistical Methods; PEAKSON, Grammar of Science; BOWLEV, Elements of Statistics.
versa.
^Ve desire a numerical measure for this correlation. Any adequate expression must be such that it becomes zero when there is no correlation, — 1 when there is perfect negative correlation, + 1 for perfect positive correlation, and which is always between — 1 and + 1. Yule has proposed a formula which satisfies these conditions. Arrange the observed data with reference to the two quantities in question as in the following diagram :
tion between use of fertilizer and yield.
233. Correlation Table. Let it be proposed to find the degree of correlation, if any, between the lengths of ears of corn and their weight, between their lengths and number of rows of kernels, between length and circumference, between length and yield per acre, between length of head of wheat and yield per acre, between height of wheat and yield per acre. The problem is now more complex. Let us take for example a given number of ears of corn and examine them as to weight in ounces and length in inches. The measurements may be tabulated as shown in the accompanying table. Each column is a frequency distribution of lengths for a constant weight. Each row is a frequency distribution of weights for a constant length. The distribution of the ears of length 8 inches with respect to weight is 3, 7, 19, 25, 17, 22, 17, 3, 1.
It is to be noticed that the table extends across the enclosing rectangle from the upper left-hand corner to the lower righthand corner. Whenever data tabulated with respect to two measurable characters show this skew arrangement, correlation exists. In the accompanying table weights increase from left
CORRELATION
to right and lengths increase as we move downward. We have in this case positive correlation. An extension of the array from the upper right-hand corner to the lower left would have indicated negative correlation.
with the above table. Find the arithmetic mean of each character involved — in this case mean length of ear, MI, and mean weight of ears, Mw. Find the deviation DI of ear length from mean length, and the deviation Dw of weight from mean weight, for each ear tabulated. For each ear tabulated find the product of DI and Dw and then add all of these products. This sum we will indicate by 3DiDw. Find in the usual way the standard deviation of length of ears, <TI, and the standard deviation of weight of ears, <rw. Then the coefficient of correlation, r, is
Dw for each ear weight is shown in the table below.
The row labeled 6.5 inches (table § 233), gives the frequency distribution of ears with respect to weight. There is one ear of weight 4 oz., 6 ears of weight 5 oz., 11 ears of weight 6 oz., 26 ears of weight 7 oz., etc.; a total of 70 ears, fi, of length 6.5 inches. fiVi = 1X4 + 6X5 + 11X6 + 26 X7 + 11X8 + 8X9
All of the symbols used have been defined with the exception of the following : <r/ is the standard deviation of length ; /„, is the number (frequency) of ears of same weight w ; Vi stands for the value of length of ears with given frequency ; Vw represents the value of weight of ears with given frequency. This gives MI = 7.85. In the row labeled 6.5 and in the column headed DI we write the difference between this mean length 7.85 and the length 6.5. This gives the number — 1.3 of the column headed D/. The number 306.8 in the last column is obtained as follows :
That is, the ear of weight 4 oz. deviates from the mean weight by 6.7 oz., the 6 ears of weight 5 oz. deviate from the mean weight by 5.7 oz., the 11 ears of weight 6 oz. deviate from the mean weight by 4.7 oz., etc.
The number 306.8 represents the sum of the products of the corresponding length and weight deviations for every individual in the horizontal row to which the number belongs. To find the correlation coefficient add the numbers in the column headed DiDw, obtaining in this case 4947.2.
Divide this number 4947.2 by n X <TI X «•„. In this case n = 993, and <TI, ffw have been computed to be 1.57 and 3.63 respectively. This gives the correlation coefficient
235. The Regression Curve. For each recorded height (see table, § 233) compute the arithmetic average of length of ears. Thus the ears of weight 4 oz. have an average length of 5.1 inches. The ears of weight 5 oz. have an average length of 5.46 inches, etc. Plot a curve using for abscissas the weights, and for ordinates the computed average lengths. The curve so plotted is called a regression curve. In many cases this curve is a straight line. It can be shown that the straight line which best represents the plotted data is given by the equation
Another regression curve can be plotted for the same data, using lengths as ordinates and mean weights for abscissas. This curve does not in general coincide with the first. Its equation is
4. From Table II, p. 312, which gives the correlation of height of oat plants with the average number per plant of kernels per culm, compute the mean height, the mean number of kernels per culm, the standard deviation with respect to height, the standard deviation with respect to number of kernels per culm, the correlation coefficient, and the regression coefficients.
Me — mean height of adult children, ffp = standard deviation of height of mid-parents, ffe = standard deviation of height of adult children, r = the correlation coefficient, and both regression coefficients.
9. Construct a correlation table from your own observations on length and breadth of leaves, (a) Use 30 classes for length, (fe) Use 15 classes for length, thus making the class interval twice as large. Compute in each case the correlation coefficient.
10. From Table I, below, which gives the conslation of lengths and weights of ears of corn, compute the mean length, the mean weight, the standard deviation with respect to length, the standard deviation with respect to weight, the correlation coefficient, and both regression coefficients.
II. CORRELATION OP AVERAGE HEIGHT OF OAT PLANTS IN CENTIMETERS AND AVERAGE NUMBER OF KERNELS PER CULM PER PLANT. [LOVE-LEIGHTY.] r = 0.73.
DIRECT READING OF THE VALUES. This table gives the sines, cosines, tangents and cotangents of the angles from 0° to 45°; and by a simple device, indicated by the printing, the values of these functions for angles from 45° to 90° may be read directly from the same table. For angles less than 45° read down the page, the degrees and minutes being found on the left; for angles greater than 45° read up the page the degrees and minutes being found on the right.
To find a function of an angle (such as 15° 27', for example) we employ the process of interpolation. To illustrate, let us find tan 15° 27'. In the table we find tan 15° 20' = .2742 and tan 15° 30' = .2773; we know that tan 15° 27' lies between these two numbers. The process of interpolation depends on the assumption that between 15° 20' and 15° 30' the tangent of the angle varies directly as the angle; while this assumption is not strictly true, it gives an approximation sufficiently accurate for a four-place table. Thus we should assume that tan 15° 25' is halfway between .2742 and .2773. We may state the problem as follows: An increase of 10' in the angle increases the tangent .0031; assuming that the tangent varies as the angle, an increase of 7' in the angle will increase the tangent by .7 X .0031 = .00217. Retaining only four places we write this .0022. Hence
The difference between two successive values in the table is called the tabular difference (.0031 above). The proportional part of the tabular difference which is used is called the correction (.0022 above), and is found by multiplying the tabular difference by the appropriate fraction (.7 above).
Rule. To find a trigonometric function of an angle by interpolation: select the angle in the table which is next smaller than the given angle, and read its sine (cosine, tangent, or cotangent as the case may be) and the tabular difference. Compute the correction as the proper proportional part of the tabular difference. In case of sines or tangents ADD the correction: in case of cosines or cotangents, SUBTRACT it.
Looking in the table we find the sine which is next less than the given sine to be .3283, and this belongs to 19° 10'. Subtract the value of the sine selected from the given sine to obtain the actual difference = .0011; note that the tabular difference = .0028. We may state the problem as follows: an increase of .0028 in the function increases the angle 10'; then aa increase of .0011 in the function will increase the angle 11/28 of 10 = 4 (to be added). Hence x = 19° 14'.
The cosine in the table next less than this is .2896 and belongs to 73° 10'; the tabular difference is 28; the actual difference is 4; correction = 4/28 of 10 = 1 (to be subtracted). Hence x = 73° 9'.
FOUR PLACE TABLES 333
Rule. To find an angle when one of its trigonometric functions is given: select from the table the same named function which is next less than the given function, noting the corresponding angle and the tabular difference: compute the actual difference (between the selected value of the function and the given value), divide it by the tabular difference, and multiply the result by 10; this gives the correction which is to be added if the given function is sine or tangent, and to be subtracted if the given function is cosine or cotangent.
3. THE LOGARITHMS OF THE TRIGONOMETRIC FUNCTIONS. If it is
required to find log sin 63° 52', the most obvious way is to find sin 63° 52' = .8978, and then to find in Table I, log .8978 = 9.9532 - 10, but this involves consulting two tables. To avoid the necessity of doing this, Table II gives the logarithms of the sines, cosines, tangents, and cotangents. The student should note that the sines and cosines of all acute angles, the tangents of all acute angles less than 45° and the cotangents of all acute angles greater than 45° are proper fractions, and their logarithms end with — 10, which is not printed in the table, but which should be written down whenever such a logarithm is used.
In the row having 58° 20' on the right and in the column having sine at the bottom find log sin 58° 20' = 9.9300 - 10; the tabular difference is 8; correction = .4 X 8 = 3 (to be added). Hence
The log tan in Table II next less than the given one is 0.0253 and belongs to 46° 40'; actual difference is 10; tabular difference is 25; correction = 10/25 of 10 = 4. Hence x = 46° 44'.
The logarithmic cosine next less than the given one is 9.9725 — 10 and belongs to 20° 10'; actual difference = 1; tabular difference = 5; correction = 1/5 X 10 = 2 (subtract). Hence x = 20° 8'.
FROM THE PREFACE
The book contains a minimum of purely theoretical matter. Its entire organization is intended to give a clear view of the meaning and the immediate usefulness of Trigonometry. The proofs, however, are in a form that will not require essential revision in the courses that follow. . . .
The number of exercises is very large, and the traditional monotony is broken by illustrations from a variety of topics. Here, as well as in the text, the attempt is often made to lead the student to think for himself by giving suggestions rather than completed solutions or demonstrations.
The text proper is short; what is there gained in space is used to make the tables very complete and usable. Attention is called particularly to the complete and handily arranged table of squares, square roots, cubes, etc. ; by its use the Pythagorean theorem and the Cosine Law become practicable for actual computation. The use of the slide rule and of four-place tables is encouraged for problems that do not demand extreme accuracy.
Only a few fundamental definitions and relations in Trigonometry need be memorized; these are here emphasized. The great body of principles and processes depends upon these fundamentals; these are presented in this book, as they should be retained, rather by emphasizing and dwelling upon that dependence. Otherwise, the subject can have no real educational value, nor indeed any permanent practical value.
A textbook for the freshman year in colleges, universities, and technical schools, giving a unified treatment of the essentials of trigonometry, college algebra, and analytic geometry, and introducing the student to the fundamental conceptions of calculus.
The various subjects are unified by the great centralizing theme of functionality so that each subject, without losing its fundamental character, is shown clearly in its relationship to the others, and to mathematics as a whole.
More emphasis is placed on insight and understanding of fundamental conceptions and modes of thought ; less emphasis on algebraic technique and facility of manipulation. Due recognition is given to the cultural motive for the study of mathematics and to the disciplinary value.
Combines with analytic geometry a number of topics, traditionally treated in college algebra, that depend upon or are closely associated with geometric representation. If the student's preparation in elementary algebra has been good, this book contains sufficient algebraic material to enable him to omit the usual course in College Algebra without essential harm. On the other hand, the book is so arranged that, for those students who have a college course in algebra, the algebraic sections may either be omitted entirely or used only for review. The book contains a great number of fundamental applications and problems. Statistics and elementary laws of Physics are introduced early, even before the usual formulas for straight lines. Polynomials and other simple explicit functions are dealt with before the more complicated implicit equations, with the exception of the circle, which is treated early. The representation of functions is made more prominent than the study of the geometric properties of special curves. Purely geometric topics are not neglected.
This work combines with analytic geometry a number of topics traditionally treated in college algebra that depend upon or are closely associated with geometric sensation. Through this combination it becomes possible to show the student more directly the meaning and the usefulness of these subjects.
The idea of coordinates is so simple that it might (and perhaps should) be explained at the very beginning of the study of algebra and geometry. Real analytic geometry, however, begins only when the equation in two variables is interpreted as defining a locus. This idea must be introduced very gradually, as it is difficult for the beginner to grasp. The familiar loci, straight line and circle, are therefore treated at great length.
in connection with the circle.
The treatment of solid analytic geometry follows the more usual lines. But, in view of the application to mechanics, the idea of the vector is given some prominence; and the representation of a function of two variables by contour lines as well as by a surface in space is explained and illustrated by practical examples.
The exercises have been selected with great care in order not only to furnish sufficient material for practice in algebraic work but also to stimulate independent thinking and to point out the applications of the theory to concrete problems. The number of exercises is sufficient to allow the instructor to make a choice.
To reduce the course presented in this book to about half its extent, the parts of the text in small type, the chapters on solid analytic geometry, and the more difficult problems throughout may be omitted.
This book presents as many and as varied applications of the Calculus as it is possible to do without venturing into technical fields whose subject matter is itself unknown and incomprehensible to the student, and without abandoning an orderly presentation of fundamental principles.
The same general tendency has led to the treatment of topics with a view toward bringing out their essential usefulness. Rigorous forms of demonstration are not insisted upon, especially where the precisely rigorous proofs would be beyond the present grasp of the student. Rather the stress is laid upon the student's certain comprehension of that which is done, and his conyiction that the results obtained are both reasonable and useful. At the same time, an effort has been made to avoid those grosser errors and actual misstatements of fact which have often offended the teacher in texts otherwise attractive and teachable.
Purely destructive criticism and abandonment of coherent arrangement are just as dangerous as ultra-conservatism. This book attempts to preserve the essential features of the Calculus, to give the student a thorough training in mathematical reasoning, to create in him a sure mathematical imagination, and to meet fairly the reasonable demand for enlivening and enriching the subject through applications at the expense of purely formal work that contains no essential principle.
in the University of Missouri
Plane and Solid Geometry, doth, izmo, 319 pp., $125 Plane Geometry, cloth, I2mo, 213 pp., $ .80 Solid Geometry, doth, I2mo, 106 pp., $ .80
tape binding that is characteristic of Macmillan textbooks.
"Geometry is likely to remain primarily a cultural, rather than an information subject,"" say the authors in the preface. " But the intimate connection of geometry with human activities is evident upon every hand, and constitutes fully as much an integral part of the subject as does its older logical and scholastic aspect." This connection with human activities, this application of geometry to real human needs, is emphasized in a great variety of problems and constructions, so that theory and application are inseparably connected throughout the book.
These illustrations and the many others contained in the book will be seen to cover a wider range than is usual, even in books that emphasize practical applications to a questionable extent. This results in a better appreciation of the significance of the subject on the part of the student, in that he gains a truer conception of the wide scope of its application.
The logical as well as the practical side of the subject is emphasized.
Definitions, arrangement, and method of treatment are logical. The definitions are particularly simple, clear, and accurate. The traditional manner of presentation in a logical system is preserved, with due regard for practical applications. Proofs, both foimal and informal, are strictly logical.
A reasonably accurate slide-rule may be made by the student, for temporary practice, as follows. Take three strips of heavy stiff cardboard 1".3 wide by 6" long; these are shown in cross-section in (1), (2), (3) above. On (3) paste or glue the adjoining cut of the slide rule. Then cut strips (2) and (3) accurately along the lines marked. Paste or glue the pieces together as shown in (4) and (5). Then (5) forms the
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rRkfjCcF9Nw6BSBQ | The ternary system : benzene, acetic acid and water. | BY A. T. LINCOLN
It was shown by Bancroft,1 about ten years ago, that the condition of equilibrium in a large number of cases of physical reactions could be represented by the Law of Mass Action ; that the exponential factors are not necessarily integers and in most cases are not ; and that, as in the case of chemical reactions, they are independent of the temperature. He showed that in the case of two non-miscible liquids and a consolute liquid, the equilibria can be represented by the Mass Caw Equation, and that there are only two sets of equilibria over the whole range of concentration, and these are represented by two different equations. He has shown the application of the mass law to a large number of other cases of physical reactions, such as, to two partially miscible liquids and a consolute liquid, to the precipitation of a salt by a liquid, to the precipitation of a liquid by a salt, and to the precipitation of one salt by another. In none of these latter cases, however, has the relation between the facts and theory been worked out as yet with a very high degree of accuracy.
In the case of one ternary system, benzene, water, and alcohol, the writer2 has shown that the Mass Caw Equation does represent the conditions of equilibria with a very high degree of accuracy, and that the Caw of Mass Action is applicable to this physical reaction, also, that the exponential factors are independent of the temperature as in the case of chemical reactions. Previously, Waddell3 studied the system, benzene, acetic acid, and water. He concludes from his experiments, that the Caw of Mass Action does not apply to this physical reaction, that the equilibria are not represented by simple expo-
Benzene , Acetic Acid and Water
nential formulae, and that at higher temperatures the deviation from the Mass Law Equation is very much more pronounced than at lower temperatures. In view of the fact that my work had shown such a marked approximation of the experimental results to the values required by the theory in the case of a system analogous to this one with which Waddell worked, it seemed worth while to repeat his work and to ascertain if his conclusions are correct. With this in view the work was undertaken, and the results are given below.
The thiophene-free benzene employed was fractionated and that portion coming over at 79.50 C under a pressure of 755.8 mm was collected and then recrystallized twice. The distilled water of the laboratory was treated with barium hydroxide in contact with which it remained for several days, when it was siphoned off and distilled. This distillate was collected by means of a block tin condenser and only the middle portion of the distillate was collected. A sample of the acetic acid was fractionated a number of times and the portion coming over between 115011 6. 50 was collected and recrystallized many times. This sample had a melting-point of 14.6°, and according to Allen,1 represents a purity of 98.7 percent. On titration with a N/40 barium hydroxide solution it was found to be 98.6 percent pure. In all the following work a correction was made for the water contained in acetic acid of this purity.
All of the flasks and bottles used were thoroughly cleaned and steamed. The bottles in which the benzene, water and acetic acid, as well as the standard solution of barium hydroxide, were stored, were connected with accurately calibrated burettes, which were so arranged that the air which entered the bottles passed through drying vessels containing sulphuric acid or potassium hydroxide. They were, also, so connected that when the burettes were emptied, the air which took the place of the liquid came from the storage bottles. By these precautions the solutions were thoroughly protected during the series of experiments.
The determinations were made in 50 cc flasks (or in- 200 cc flasks) which had been thoroughly cleaned and steamed. Into one of the flasks were introduced 5 cc of acetic acid (or 100 cc) and to this was added a definite quantity of benzene, and then enough water was introduced to produce clouding at room temperature. The mixture was then warmed up a few degrees above the temperature at which the determination was to be made. When the contents of the flask became homogeneous the flask was transferred to a bath which was kept at the desired temperature. After remaining in the bath long enough to acquire the temperature of the same, if clouding did not result, the flask was removed, and a few drops of water added from the burette, and the flask warmed until the contents became homogeneous, when it was returned to the bath and allowed to remain with occasional shaking until it had acquired the temperature of the bath. If clouding did not result, this process was continued until it was found that one drop of water caused the second liquid layer to appear. In order to. ascertain this point the flask had to be removed from the bath in which it was kept. So in order to make the observation and at the same time prevent the clouding resulting from cooling the walls of the flasks by contact with the air, the flasks were placed in a beaker in the bath and the beaker containing the flask and water from the bath was removed and the observation made.
The bath employed was an ordinary Ostwald thermostat provided with a water turbine for stirring and no difficulty was experienced in keeping the temperature constant to within a few hundredths of a degree.
In the manner just described the data given in the following tables were collected. In Table I are the data for the equilibrium determinations at 25 0 C and the calculated values for the amount of water that should have been found and also the values of the constant are given in the last column. The headings of the other columns are self-explanatory.
0.2496
One of the greatest difficulties to be contended with in the experimental work was obtaining the point of equilibrium. It was difficult to detect the appearance of the second liquid layer as it did not manifest itself in the same manner over the whole range of concentration. Over one portion there was first a very slight opalescence which, upon further addition of water, increased until a decided cloudiness resulted, and finally the second liquid layer was very apparent. Over the other portion of the concentrations where the water was in excess of the benzene, the second liquid layer appeared as fine clear globules which floated on the surface, thus indicating that it was the benzene layer that was separating out. Owing to these two different appearances of the second liquid layer, it was somewhat difficult to determine the true point of equilibrium.
It was no doubt this difficulty which presented itself to Waddell when he determined the equilibrium of the system benzene, acetic acid and water, for he states that he took as the endpoint, i. e., as the point of equilibrium, the same degree of clouding. That one cannot use the same degree of clouding as the end-point for the establishment of equilibrium is very apparent
0.8331
from the fact that in one portion of the series of concentrations there is a decided clouding, while at the other end of the series there is no clouding, but the separation of the second liquid layer as clear transparent globules. In that portion of the concentrations where decided clouding does take place, the same de-
gree of clouding does not represent the points of equilibrium. For example, in one experiment, No. 3 at 30°, it requires 1.56 cc of water to produce a decided opalescence and 1.79 cc to produce a decided clouding, while in another experiment opalescence was produced by the addition of 2.18 cc, while the same degree of clouding as in the preceding experiment was produced by 2.30 cc of water. The calculated value in the first case was 1.58 cc and in the second 2.16 ccof water. In Table II, column 3, are the values of the quantities of water that were required to produce the same degree of clouding in these various cases. By comparison with the corresponding values in column 2 it will be observed how much more was required than that just necessary to produce the decided opalescence which we took as the indication of the appearance of the second liquid layer, that is, as the point of equilibrium. From this I think we are justified in concluding that Waddell’s results are wrong. He was not working with a system in equilibrium, but had an excess of one of the components, and for that reason we could not expect the results to conform to the law of Mass Action.
If we apply the law of Mass Action to the data given in the tables above wherein we let x = cc of benzene, y — cc of water, and 2 = cc of acetic acid, then our equation takes the form xayp — 2a + p. Since the acetic acid was kept constant and we have xayp = C1, and if we define a//3 = n , our equation then takes the form xny — C, or expressed logarithmically, we have n log x + log y = log C. Now this is in the form of the equation of a straight line wherein we have the logarithm of the quantities in place of the quantities themselves. Hence, if we plot the logarithm of the quantities of benzene and water used, the resulting curve should be a straight line with the slope n. From this curve the value of n can be determined, which in the case of the determinations at 250 C given in Table I are plotted on Fig. 1. It will be readily seen that we have two distinct curves and that one curve does not represent the condition of equilibrium over the whole range of concentration ; but confirms Bancroft’s statements that for two non-miscible liquids and a consolute liquid there are two sets of equilibria, and we have
two curves corresponding to these two sets of equilibria. Further, the different end-points seem to correspond with these two sets, for over the greater part of one we get the second liquid layer appearing as fine transparent globules and over a considerable part of the other as an opalescence. Having determined the values for n and n\ we then have the distinct curves of different slopes. If now we substitute the value of n and n ' in their respective equations we obtain the values for log C and log C1 as given in the last column. If the mean value be substituted in our formula and we solve for the value of the amount of water that should have been added, we obtain the values given in column y calc , which agrees fairly well with those found experimentally and given in column 2. Under x calc are given the calculated values for benzene, assuming the value of y known.
Fig. 1
If this physical reaction follows the Mass Law the exponential factors should be independent of the temperature, i. e., the values of n should be the same at whatever temperatures the equilibrium is established. Waddell states that at 35 0 C the deviation of this equilibrium from the Mass Law is even more
pronounced than at 250 C. A series of determinations was made at 350 C and the results are given in Table II, and the plotted results are represented in Fig. 1. It will be observed that there are two curves corresponding to the two equilibria and further the value of n (0.61) at 350 is very nearly the same as n (0.6136) at 250, while the values for n’ (0.92 against 0.9166) are almost exactly the .same at both temperatures. Hence it seems that we are justified in concluding that the temperature does not affect the value of the exponential factor and that this physical reaction between benzene, acetic acid and water conforms to the Mass Law Equation.
| 2,655 | common-pile/pre_1929_books_filtered | ternarysystemben00linc | public_library | public_library_1929_dolma-0008.json.gz:629 | https://archive.org/download/ternarysystemben00linc/ternarysystemben00linc_djvu.txt |
aRvH3BQy2snYU7DI | 8.6: Transformers as Two-Port Devices | 8.6: Transformers as Two-Port Devices
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Section 8.5 explains the principle of operation of the ideal transformer. The relationship governing the terminal voltages \(V_1\) and \(V_2\) was found to be \[\frac{V_1}{V_2} = p\frac{N_1}{N_2} \nonumber \] where \(N_1\) and \(N_2\) are the number of turns in the associated coils and \(p\) is either \(+1\) or \(-1\) depending on the relative orientation of the windings; i.e., whether the reference direction of the associated fluxes is the same or opposite, respectively.
Figure \(\PageIndex{1}\): The transformer as a two-port circuit device.We shall now consider ratios of current and impedance in ideal transformers, using the two-port model shown in Figure \(\PageIndex{1}\). By virtue of the reference current directions and polarities chosen in this figure, the power delivered by the source \(V_1\) is \(V_1 I_1\), and the power absorbed by the load \(Z_2\) is \(-V_2 I_2\). Assuming the transformer windings have no resistance, and assuming the magnetic flux is perfectly contained within the core, the power absorbed by the load must equal the power provided by the source; i.e., \(V_1 I_1 = -V_2 I_2\). Thus, we have 1
\[\boxed{ \frac{I_1}{I_2} = -\frac{V_2}{V_1} = -p\frac{N_2}{N_1} } \nonumber \]
We can develop an impedance relationship for ideal transformers as follows. Let \(Z_1\) be the input impedance of the transformer; that is, the impedance looking into port 1 from the source. Thus, we have
\begin{aligned}
Z_{1} & \triangleq \frac{V_{1}}{I_{1}} \\
&=\frac{+p\left(N_{1} / N_{2}\right) V_{2}}{-p\left(N_{2} / N_{1}\right) I_{2}} \\
&=-\left(\frac{N_{1}}{N_{2}}\right)^{2}\left(\frac{V_{2}}{I_{2}}\right)
\end{aligned}
In Figure \(\PageIndex{1}\), \(Z_2\) is the the output impedance of port 2; that is, the impedance looking out port 2 into the load. Therefore, \(Z_2 = -V_2/I_2\) (once again the minus sign is a result of our choice of sign conventions in Figure \(\PageIndex{1}\)). Substitution of this result into the above equation yields
\[Z_1 = \left(\frac{N_1}{N_2}\right)^2 Z_2 \nonumber \]
and therefore \[\boxed{ \frac{Z_1}{Z_2} = \left(\frac{N_1}{N_2}\right)^2 } \nonumber \] Thus, we have demonstrated that a transformer scales impedance in proportion to the square of the turns ratio \(N_1/N_2\). Remarkably, the impedance transformation depends only on the turns ratio, and is independent of the relative direction of the windings (\(p\)).
The relationships developed above should be viewed as AC expressions, and are not normally valid at DC. This is because transformers exhibit a fundamental limitation in their low-frequency performance. To see this, first recall Faraday’s Law:
\[V = - N \frac{\partial}{\partial t} \Phi \nonumber \]
If the magnetic flux \(\Phi\) is not time-varying, then there is no induced electric potential, and subsequently no linking of the signals associated with the coils. At very low but non-zero frequencies, we encounter another problem that gets in the way – magnetic saturation . To see this, note we can obtain an expression for \(\Phi\) from Faraday’s Law by integrating with respect to time, yielding
\[\Phi(t) = -\frac{1}{N}\int_{t_0}^{t}V(\tau)d\tau + \Phi(t_0) \nonumber \]
where \(t_0\) is some earlier time at which we know the value of \(\Phi(t_0)\). Let us assume that \(V(t)\) is sinusoidally-varying. Then the peak value of \(\Phi\) after \(t=t_0\) depends on the frequency of \(V(t)\). If the frequency of \(V(t)\) is very low, then \(\Phi\) can become very large. Since the associated cross-sectional areas of the coils are presumably constant, this means that the magnetic field becomes very large. The problem with that is that most practical high-permeability materials suitable for use as transformer cores exhibit magnetic saturation; that is, the rate at which the magnetic field is able to increase decreases with increasing magnetic field magnitude (see Section 7.16). The result of all this is that a transformer may work fine at (say) 1 MHz, but at (say) 1 Hz the transformer may exhibit an apparent loss associated with this saturation. Thus, practical transformers exhibit highpass frequency response.
It should be noted that the highpass behavior of practical transistors can be useful. For example, a transformer can be used to isolate an undesired DC offset and/or low-frequency noise in the circuit attached to one coil from the circuit attached to the other coil.
The DC-isolating behavior of a transformer also allows the transformer to be used as a balun , as illustrated in Figure \(\PageIndex{2}\). A balun is a two-port device that transforms a single-ended (“unbalanced”) signal – that is, one having an explicit connection to a datum (e.g., ground) – into a differential (“balanced”) signal, for which there is no explicit connection to a datum. Differential signals have many benefits in circuit design, whereas inputs and outputs to devices must often be in single-ended form. Thus, a common use of transformers is to effect the conversion between single-ended and differential circuits. Although a transformer is certainly not the only device that can be used as a balun, it has one very big advantage, namely bandwidth.
Figure \(\PageIndex{2}\): Transformers used to convert a singleended (“unbalanced”) signal to a differential (balanced) signal, and back. (© CC BY SA 3.0 (modified); SpinningSpark)Additional Reading:
- S.W. Ellingson, “Differential Circuits” (Sec. 8.7) in Radio Systems Engineering , Cambridge Univ. Press, 2016.
- The minus signs in this equation are a result of the reference polarity and directions indicated in Figure \(\PageIndex{1}\). These are more-or-less standard in electrical two-port theory (see “Additional Reading” at the end of this section), but are certainly not the only reasonable choice. If you see these expressions without the minus signs, it probably means that a different combination of reference directions/polarities is in effect.↩ | 1,168 | common-pile/libretexts_filtered | https://phys.libretexts.org/Courses/Berea_College/Electromagnetics_I/08%3A_Time-Varying_Fields/8.06%3A_Transformers_as_Two-Port_Devices | libretexts | libretexts-0000.json.gz:32892 | https://phys.libretexts.org/Courses/Berea_College/Electromagnetics_I/08%3A_Time-Varying_Fields/8.06%3A_Transformers_as_Two-Port_Devices |
3QPn-85ZfqVx91-q | Hymns and Spiritual Songs | H. Alford
COME, ye thankful people, come,
Raise the song of harvest-home:
All is safely gathered in,
Ere the winter storms begin;
God, our Maker doth provide
For our wants to be supplied:
Come to God’s own temple, come,
Raise the song of harvest-home.
2
All the world is God’s own field,
Fruit unto His praise to yield;
Wheat and tares together sown,
Unto joy or sorrow grown;
First the blade, and then the ear,
Then the full corn shall appear:
Lord of harvest, grant that we
Wholesome grain and pure may be.
3
For the Lord our God shall come,
And shall take His harvest home;
From His field shall in that day
All offenses purge away;
Give His angels charge at last
In the fire the tares to cast;
But the fruitful ears to store
In His garner evermore.
4
Even so, Lord, quickly come
To Thy final harvest-home;
Gather Thou Thy people in,
Free from sorrow, free from sin;
There, forever purified,
In Thy presence to abide:
Come, with all Thine angels, come,
Raise the glorious harvest-home. | 234 | common-pile/pressbooks_filtered | https://pressbooks.pub/hymnbook/chapter/come-ye-thankful-people-come/ | pressbooks | pressbooks-0000.json.gz:96412 | https://pressbooks.pub/hymnbook/chapter/come-ye-thankful-people-come/ |
u404fJNQg5MNbP-l | General Psychology 2e | 8
CHAPTER OUTLINE
5.1 Sensation versus Perception
5.2 Waves and Wavelengths
5.3 Vision
5.4 Hearing
5.5 The Other Senses
5.6 Gestalt Principles of Perception
INTRODUCTION: Imagine standing on a city street corner. You might be struck by movement everywhere as cars and people go about their business, by the sound of a street musician’s melody or a horn honking in the distance, by the smell of exhaust fumes or of food being sold by a nearby vendor, and by the sensation of hard pavement under your feet.
We rely on our sensory systems to provide important information about our surroundings. We use this information to successfully navigate and interact with our environment so that we can find nourishment, seek shelter, maintain social relationships, and avoid potentially dangerous situations.
This chapter will provide an overview of how sensory information is received and processed by the nervous system and how that affects our conscious experience of the world. We begin by learning the distinction between sensation and perception. Then we consider the physical properties of light and sound stimuli, along with an overview of the basic structure and function of the major sensory systems. The chapter will close with a discussion of a historically important theory of perception called Gestalt.
5.1 Sensation and Perception
LEARNING OBJECTIVES
- Distinguish between sensation and perception
- Describe the concepts of absolute threshold and difference threshold
- Discuss the roles attention, motivation, and sensory adaptation play in perception
Sensation
What does it mean to sense something? Sensory receptors are specialized neurons that respond to specific types of stimuli. When sensory information is detected by a sensory receptor, sensation has occurred. For example, light that enters the eye causes chemical changes in cells that line the back of the eye. These cells relay messages, in the form of action potentials (as you learned when studying biopsychology), to the central nervous system. The conversion from sensory stimulus energy to action potential is known as transduction.
You have probably known since elementary school that we have five senses: vision, hearing (audition), smell (olfaction), taste (gustation), and touch (somatosensation). It turns out that this notion of five senses is oversimplified. We also have sensory systems that provide information about balance (the vestibular sense), body position and movement (proprioception and kinesthesia), pain (nociception), and temperature (thermoception).
The sensitivity of a given sensory system to the relevant stimuli can be expressed as an absolute threshold. Absolute threshold refers to the minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time. Another way to think about this is by asking how dim can a light be or how soft can a sound be and still be detected half of the time. The sensitivity of our sensory receptors can be quite amazing. It has been estimated that on a clear night, the most sensitive sensory cells in the back of the eye can detect a candle flame 30 miles away (Okawa & Sampath, 2007). Under quiet conditions, the hair cells (the receptor cells of the inner ear) can detect the tick of a clock 20 feet away (Galanter, 1962).
It is also possible for us to get messages that are presented below the threshold for conscious awareness—these are called subliminal messages. A message below that threshold is said to be subliminal: We receive it, but we are not consciously aware of it. Over the years there has been a great deal of speculation about the use of subliminal messages in advertising, rock music, and self-help audio programs. Research evidence shows that in laboratory settings, people can process and respond to information outside of awareness. But this does not mean that we obey these messages like zombies; in fact, hidden messages have little effect on behavior outside the laboratory (Kunst-Wilson & Zajonc, 1980; Rensink, 2004; Nelson, 2008; Radel, Sarrazin, Legrain, & Gobancé, 2009; Loersch, Durso, & Petty, 2013).
Absolute thresholds are generally measured under incredibly controlled conditions in situations that are optimal for sensitivity. Sometimes, we are more interested in how much difference in stimuli is required to detect a difference between them. This is known as the just noticeable difference (jnd) or difference threshold. Unlike the absolute threshold, the difference threshold changes depending on the stimulus intensity. As an example, imagine yourself in a very dark movie theater. If an audience member were to receive a text message that caused the cell phone screen to light up, chances are that many people would notice the change in illumination in the theater. However, if the same thing happened in a brightly lit arena during a basketball game, very few people would notice. The cell phone brightness does not change, but its ability to be detected as a change in illumination varies dramatically between the two contexts. Ernst Weber proposed this theory of change in difference threshold in the 1830s, and it has become known as Weber’s law: The difference threshold is a constant fraction of the original stimulus, as the example illustrates.
Perception
While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to sensory information from a stimulus in the environment driving a process, and top-down processing refers to knowledge and expectancy driving a process, as shown in Figure 5.2 (Egeth & Yantis, 1997; Fine & Minnery, 2009; Yantis & Egeth, 1999).
Alternatively, top-down processes are generally goal directed, slow, deliberate, effortful, and under your control (Fine & Minnery, 2009; Miller & Cohen, 2001; Miller & D’Esposito, 2005). For instance, if you misplaced your keys, how would you look for them? If you had a yellow key fob, you would probably look for yellowness of a certain size in specific locations, such as on the counter, coffee table, and other similar places. You would not look for yellowness on your ceiling fan, because you know keys are not normally lying on top of a ceiling fan. That act of searching for a certain size of yellowness in some locations and not others would be top-down—under your control and based on your experience.
One way to think of this concept is that sensation is a physical process, whereas perception is psychological. For example, upon walking into a kitchen and smelling the scent of baking cinnamon rolls, the sensation is the scent receptors detecting the odor of cinnamon, but the perception may be “Mmm, this smells like the bread Grandma used to bake when the family gathered for holidays.”
Although our perceptions are built from sensations, not all sensations result in perception. In fact, we often don’t perceive stimuli that remain relatively constant over prolonged periods of time. This is known as sensory adaptation. Imagine going to a city that you have never visited. You check in to the hotel, but when you get to your room, there is a road construction sign with a bright flashing light outside your window. Unfortunately, there are no other rooms available, so you are stuck with a flashing light. You decide to watch television to unwind. The flashing light was extremely annoying when you first entered your room. It was as if someone was continually turning a bright yellow spotlight on and off in your room, but after watching television for a short while, you no longer notice the light flashing. The light is still flashing and filling your room with yellow light every few seconds, and the photoreceptors in your eyes still sense the light, but you no longer perceive the rapid changes in lighting conditions. That you no longer perceive the flashing light demonstrates sensory adaptation and shows that while closely associated, sensation and perception are different.
There is another factor that affects sensation and perception: attention. Attention plays a significant role in determining what is sensed versus what is perceived. Imagine you are at a party full of music, chatter, and laughter. You get involved in an interesting conversation with a friend, and you tune out all the background noise. If someone interrupted you to ask what song had just finished playing, you would probably be unable to answer that question.
One of the most interesting demonstrations of how important attention is in determining our perception of the environment occurred in a famous study conducted by Daniel Simons and Christopher Chabris (1999). In this study, participants watched a video of people dressed in black and white passing basketballs. Participants were asked to count the number of times the team dressed in white passed the ball. During the video, a person dressed in a black gorilla costume walks among the two teams. You would think that someone would notice the gorilla, right? Nearly half of the people who watched the video didn’t notice the gorilla at all, despite the fact that he was clearly visible for nine seconds. Because participants were so focused on the number of times the team dressed in white was passing the ball, they completely tuned out other visual information. Inattentional blindness is the failure to notice something that is completely visible because the person was actively attending to something else and did not pay attention to other things (Mack & Rock, 1998; Simons & Chabris, 1999).
In a similar experiment, researchers tested inattentional blindness by asking participants to observe images moving across a computer screen. They were instructed to focus on either white or black objects, disregarding the other color. When a red cross passed across the screen, about one third of subjects did not notice it (Figure 5.3) (Most, Simons, Scholl, & Chabris, 2000).
Our perceptions can also be affected by our beliefs, values, prejudices, expectations, and life experiences. As you will see later in this chapter, individuals who are deprived of the experience of binocular vision during critical periods of development have trouble perceiving depth (Fawcett, Wang, & Birch, 2005). The shared experiences of people within a given cultural context can have pronounced effects on perception. For example, Marshall Segall, Donald Campbell, and Melville Herskovits (1963) published the results of a multinational study in which they demonstrated that individuals from Western cultures were more prone to experience certain types of visual illusions than individuals from non-Western cultures, and vice versa. One such illusion that Westerners were more likely to experience was the Müller-Lyer illusion (Figure 5.4): The lines appear to be different lengths, but they are actually the same length.
Children described as thrill seekers are more likely to show taste preferences for intense sour flavors (Liem, Westerbeek, Wolterink, Kok, & de Graaf, 2004), which suggests that basic aspects of personality might affect perception. Furthermore, individuals who hold positive attitudes toward reduced-fat foods are more likely to rate foods labeled as reduced fat as tasting better than people who have less positive attitudes about these products (Aaron, Mela, & Evans, 1994).
5.1 TEST YOURSELF
5.2 Waves and Wavelengths
LEARNING OBJECTIVES
By the end of this section, you will be able to:
- Describe important physical features of wave forms
- Show how physical properties of light waves are associated with perceptual experience
- Show how physical properties of sound waves are associated with perceptual experience
Visual and auditory stimuli both occur in the form of waves. Although the two stimuli are very different in terms of composition, wave forms share similar characteristics that are especially important to our visual and auditory perceptions. In this section, we describe the physical properties of the waves as well as the perceptual experiences associated with them.
Amplitude and Wavelength
Two physical characteristics of a wave are amplitude and wavelength (Figure 5.5). The amplitude of a wave is the distance from the center line to the top point of the crest or the bottom point of the trough. Wavelength refers to the length of a wave from one peak to the next.
Light Waves
The visible spectrum is the portion of the larger electromagnetic spectrum that we can see. As Figure 5.7 shows, the electromagnetic spectrum encompasses all of the electromagnetic radiation that occurs in our environment and includes gamma rays, x-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. The visible spectrum in humans is associated with wavelengths that range from 380 to 740 nm—a very small distance, since a nanometer (nm) is one billionth of a meter. Other species can detect other portions of the electromagnetic spectrum. For instance, honeybees can see light in the ultraviolet range (Wakakuwa, Stavenga, & Arikawa, 2007), and some snakes can detect infrared radiation in addition to more traditional visual light cues (Chen, Deng, Brauth, Ding, & Tang, 2012; Hartline, Kass, & Loop, 1978).
Sound Waves
Like light waves, the physical properties of sound waves are associated with various aspects of our perception of sound. The frequency of a sound wave is associated with our perception of that sound’s pitch. High-frequency sound waves are perceived as high-pitched sounds, while low-frequency sound waves are perceived as low-pitched sounds. The audible range of sound frequencies is between 20 and 20000 Hz, with greatest sensitivity to those frequencies that fall in the middle of this range.
As was the case with the visible spectrum, other species show differences in their audible ranges. For instance, chickens have a very limited audible range, from 125 to 2000 Hz. Mice have an audible range from 1000 to 91000 Hz, and the beluga whale’s audible range is from 1000 to 123000 Hz. Our pet dogs and cats have audible ranges of about 70–45000 Hz and 45–64000 Hz, respectively (Strain, 2003).
The loudness of a given sound is closely associated with the amplitude of the sound wave. Higher amplitudes are associated with louder sounds. Loudness is measured in terms of decibels (dB), a logarithmic unit of sound intensity. A typical conversation would correlate with 60 dB; a rock concert might check in at 120 dB (Figure 5.9). A whisper 5 feet away or rustling leaves are at the low end of our hearing range; sounds like a window air conditioner, a normal conversation, and even heavy traffic or a vacuum cleaner are within a tolerable range. However, there is the potential for hearing damage from about 80 dB to 130 dB: These are sounds of a food processor, power lawnmower, heavy truck (25 feet away), subway train (20 feet away), live rock music, and a jackhammer. About one-third of all hearing loss is due to noise exposure, and the louder the sound, the shorter the exposure needed to cause hearing damage (Le, Straatman, Lea, & Westerberg, 2017). Listening to music through earbuds at maximum volume (around 100–105 decibels) can cause noise-induced hearing loss after 15 minutes of exposure. Although listening to music at maximum volume may not seem to cause damage, it increases the risk of age-related hearing loss (Kujawa & Liberman, 2006). The threshold for pain is about 130 dB, a jet plane taking off or a revolver firing at close range (Dunkle, 1982).
Of course, different musical instruments can play the same musical note at the same level of loudness, yet they still sound quite different. This is known as the timbre of a sound. Timbre refers to a sound’s purity, and it is affected by the complex interplay of frequency, amplitude, and timing of sound waves.
5.2 TEST YOURSELF
5.3 Vision
LEARNING OBJECTIVES
By the end of this section, you will be able to:
- Describe the basic anatomy of the visual system
- Discuss how rods and cones contribute to different aspects of vision
- Describe how monocular and binocular cues are used in the perception of depth
The visual system constructs a mental representation of the world around us (Figure 5.10). This contributes to our ability to successfully navigate through physical space and interact with important individuals and objects in our environments. This section will provide an overview of the basic anatomy and function of the visual system. In addition, we will explore our ability to perceive color and depth.
Anatomy of the Visual System
The eye is the major sensory organ involved in vision (Figure 5.11). Light waves are transmitted across the cornea and enter the eye through the pupil. The cornea is the transparent covering over the eye. It serves as a barrier between the inner eye and the outside world, and it is involved in focusing light waves that enter the eye. The pupil is the small opening in the eye through which light passes, and the size of the pupil can change as a function of light levels as well as emotional arousal. When light levels are low, the pupil will become dilated, or expanded, to allow more light to enter the eye. When light levels are high, the pupil will constrict, or become smaller, to reduce the amount of light that enters the eye. The pupil’s size is controlled by muscles that are connected to the iris, which is the colored portion of the eye.
While cones are concentrated in the fovea, where images tend to be focused, rods, another type of photoreceptor, are located throughout the remainder of the retina. Rods are specialized photoreceptors that work well in low light conditions, and while they lack the spatial resolution and color function of the cones, they are involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field.
Rods and cones are connected (via several interneurons) to retinal ganglion cells. Axons from the retinal ganglion cells converge and exit through the back of the eye to form the optic nerve. The optic nerve carries visual information from the retina to the brain. There is a point in the visual field called the blind spot: Even when light from a small object is focused on the blind spot, we do not see it. We are not consciously aware of our blind spots for two reasons: First, each eye gets a slightly different view of the visual field; therefore, the blind spots do not overlap. Second, our visual system fills in the blind spot so that although we cannot respond to visual information that occurs in that portion of the visual field, we are also not aware that information is missing.
The optic nerve from each eye merges just below the brain at a point called the optic chiasm. As Figure 5.13 shows, the optic chiasm is an X-shaped structure that sits just below the cerebral cortex at the front of the brain. At the point of the optic chiasm, information from the right visual field (which comes from both eyes) is sent to the left side of the brain, and information from the left visual field is sent to the right side of the brain.
The Ethics of Research Using Animals
David Hubel and Torsten Wiesel were awarded the Nobel Prize in Medicine in 1981 for their research on the visual system. They collaborated for more than twenty years and made significant discoveries about the neurology of visual perception (Hubel & Wiesel, 1959, 1962, 1963, 1970; Wiesel & Hubel, 1963). They studied animals, mostly cats and monkeys. Although they used several techniques, they did considerable single unit recordings, during which tiny electrodes were inserted in the animal’s brain to determine when a single cell was activated. Among their many discoveries, they found that specific brain cells respond to lines with specific orientations (called ocular dominance), and they mapped the way those cells are arranged in areas of the visual cortex known as columns and hypercolumns.
In some of their research, they sutured one eye of newborn kittens closed and followed the development of the kittens’ vision. They discovered there was a critical period of development for vision. If kittens were deprived of input from one eye, other areas of their visual cortex filled in the area that was normally used by the eye that was sewn closed. In other words, neural connections that exist at birth can be lost if they are deprived of sensory input.
What do you think about sewing a kitten’s eye closed for research? To many animal advocates, this would seem brutal, abusive, and unethical. What if you could do research that would help ensure babies and children born with certain conditions could develop normal vision instead of becoming blind? Would you want that research done? Would you conduct that research, even if it meant causing some harm to cats? Would you think the same way if you were the parent of such a child? What if you worked at the animal shelter?
Like virtually every other industrialized nation, the United States permits medical experimentation on animals, with few limitations (assuming sufficient scientific justification). The goal of any laws that exist is not to ban such tests but rather to limit unnecessary animal suffering by establishing standards for the humane treatment and housing of animals in laboratories.
As explained by Stephen Latham, the director of the Interdisciplinary Center for Bioethics at Yale (2012), possible legal and regulatory approaches to animal testing vary on a continuum from strong government regulation and monitoring of all experimentation at one end, to a self-regulated approach that depends on the ethics of the researchers at the other end. The United Kingdom has the most significant regulatory scheme, whereas Japan uses the self-regulation approach. The U.S. approach is somewhere in the middle, the result of a gradual blending of the two approaches.
There is no question that medical research is a valuable and important practice. The question is whether the use of animals is a necessary or even best practice for producing the most reliable results. Alternatives include the use of patient-drug databases, virtual drug trials, computer models and simulations, and noninvasive imaging techniques such as magnetic resonance imaging and computed tomography scans (“Animals in Science/Alternatives,” n.d.). Other techniques, such as microdosing, use humans not as test animals but as a means to improve the accuracy and reliability of test results. In vitro methods based on human cell and tissue cultures, stem cells, and genetic testing methods are also increasingly available.
Today, at the local level, any facility that uses animals and receives federal funding must have an Institutional Animal Care and Use Committee (IACUC) that ensures that the NIH guidelines are being followed. The IACUC must include researchers, administrators, a veterinarian, and at least one person with no ties to the institution: that is, a concerned citizen. This committee also performs inspections of laboratories and protocols.
Color and Depth Perception
We do not see the world in black and white; neither do we see it as two-dimensional (2-D) or flat (just height and width, no depth). Let’s look at how color vision works and how we perceive three dimensions (height, width, and depth).
Color Vision
Normal-sighted individuals have three different types of cones that mediate color vision. Each of these cone types is maximally sensitive to a slightly different wavelength of light. According to the trichromatic theory of color vision, shown in Figure 5.14, all colors in the spectrum can be produced by combining red, green, and blue. The three types of cones are each receptive to one of the colors.
Colorblindness: A Personal Story
Several years ago, I dressed to go to a public function and walked into the kitchen where my 7-year-old daughter sat. She looked up at me, and in her most stern voice, said, “You can’t wear that.” I asked, “Why not?” and she informed me the colors of my clothes did not match. She had complained frequently that I was bad at matching my shirts, pants, and ties, but this time, she sounded especially alarmed. As a single father with no one else to ask at home, I drove us to the nearest convenience store and asked the store clerk if my clothes matched. She said my pants were a bright green color, my shirt was a reddish-orange, and my tie was brown. She looked at my quizzically and said, “No way do your clothes match.” Over the next few days, I started asking my coworkers and friends if my clothes matched. After several days of being told that my coworkers just thought I had “a really unique style,” I made an appointment with an eye doctor and was tested (Figure 5.15). It was then that I found out that I was colorblind. I cannot differentiate between most greens, browns, and reds.
The trichromatic theory of color vision is not the only theory—another major theory of color vision is known as the opponent-process theory. According to this theory, color is coded in opponent pairs: black-white, yellow-blue, and green-red. The basic idea is that some cells of the visual system are excited by one of the opponent colors and inhibited by the other. So, a cell that was excited by wavelengths associated with green would be inhibited by wavelengths associated with red, and vice versa. One of the implications of opponent processing is that we do not experience greenish-reds or yellowish-blues as colors. Another implication is that this leads to the experience of negative afterimages. An afterimage describes the continuation of a visual sensation after removal of the stimulus. For example, when you stare briefly at the sun and then look away from it, you may still perceive a spot of light although the stimulus (the sun) has been removed. When color is involved in the stimulus, the color pairings identified in the opponent-process theory lead to a negative afterimage. You can test this concept using the flag in Figure 5.16.
Depth Perception
Our ability to perceive spatial relationships in three-dimensional (3-D) space is known as depth perception. With depth perception, we can describe things as being in front, behind, above, below, or to the side of other things.
Our world is three-dimensional, so it makes sense that our mental representation of the world has three-dimensional properties. We use a variety of cues in a visual scene to establish our sense of depth. Some of these are binocular cues, which means that they rely on the use of both eyes. One example of a binocular depth cue is binocular disparity, the slightly different view of the world that each of our eyes receives. To experience this slightly different view, do this simple exercise: extend your arm fully and extend one of your fingers and focus on that finger. Now, close your left eye without moving your head, then open your left eye and close your right eye without moving your head. You will notice that your finger seems to shift as you alternate between the two eyes because of the slightly different view each eye has of your finger.
A 3-D movie works on the same principle: the special glasses you wear allow the two slightly different images projected onto the screen to be seen separately by your left and your right eye.
Although we rely on binocular cues to experience depth in our 3-D world, we can also perceive depth in 2-D arrays. Think about all the paintings and photographs you have seen. Generally, you pick up on depth in these images even though the visual stimulus is 2-D. When we do this, we are relying on a number of monocular cues, or cues that require only one eye. If you think you can’t see depth with one eye, note that you don’t bump into things when using only one eye while walking—and, in fact, we have more monocular cues than binocular cues.
An example of a monocular cue would be what is known as linear perspective. Linear perspective refers to the fact that we perceive depth when we see two parallel lines that seem to converge in an image (Figure 5.17). Some other monocular depth cues are interposition, the partial overlap of objects, and the relative size and closeness of images to the horizon.
DIG DEEPER
Stereoblindness
Bruce Bridgeman was born with an extreme case of lazy eye that resulted in him being stereoblind, or unable to respond to binocular cues of depth. He relied heavily on monocular depth cues, but he never had a true appreciation of the 3-D nature of the world around him. This all changed one night in 2012 while Bruce was seeing a movie with his wife.
The movie the couple was going to see was shot in 3-D, and even though he thought it was a waste of money, Bruce paid for the 3-D glasses when he purchased his ticket. As soon as the film began, Bruce put on the glasses and experienced something completely new. For the first time in his life he appreciated the true depth of the world around him. Remarkably, his ability to perceive depth persisted outside of the movie theater.
There are cells in the nervous system that respond to binocular depth cues. Normally, these cells require activation during early development in order to persist, so experts familiar with Bruce’s case (and others like his) assume that at some point in his development, Bruce must have experienced at least a fleeting moment of binocular vision. It was enough to ensure the survival of the cells in the visual system tuned to binocular cues. The mystery now is why it took Bruce nearly 70 years to have these cells activated (Peck, 2012).
5.3 TEST YOURSELF
5.4 Hearing
LEARNING OBJECTIVES
By the end of this section, you will be able to:
- Describe the basic anatomy and function of the auditory system
- Explain how we encode and perceive pitch
- Discuss how we localize sound
Our auditory system converts pressure waves into meaningful sounds. This translates into our ability to hear the sounds of nature, to appreciate the beauty of music, and to communicate with one another through spoken language. This section will provide an overview of the basic anatomy and function of the auditory system. It will include a discussion of how the sensory stimulus is translated into neural impulses, where in the brain that information is processed, how we perceive pitch, and how we know where sound is coming from.
Anatomy of the Auditory System
The ear can be separated into multiple sections. The outer ear includes the pinna, which is the visible part of the ear that protrudes from our heads, the auditory canal, and the tympanic membrane, or eardrum. The middle ear contains three tiny bones known as the ossicles, which are named the malleus (or hammer), incus (or anvil), and the stapes (or stirrup). The inner ear contains the semi-circular canals, which are involved in balance and movement (the vestibular sense), and the cochlea. The cochlea is a fluid-filled, snail-shaped structure that contains the sensory receptor cells (hair cells) of the auditory system (Figure 5.18).
The activation of hair cells is a mechanical process: the stimulation of the hair cell ultimately leads to activation of the cell. As hair cells become activated, they generate neural impulses that travel along the auditory nerve to the brain. Auditory information is shuttled to the inferior colliculus, the medial geniculate nucleus of the thalamus, and finally to the auditory cortex in the temporal lobe of the brain for processing. Like the visual system, there is also evidence suggesting that information about auditory recognition and localization is processed in parallel streams (Rauschecker & Tian, 2000; Renier et al., 2009).
Pitch Perception
Different frequencies of sound waves are associated with differences in our perception of the pitch of those sounds. Low-frequency sounds are lower pitched, and high-frequency sounds are higher pitched. How does the auditory system differentiate among various pitches?
Several theories have been proposed to account for pitch perception. We’ll discuss two of them here: temporal theory and place theory. The temporal theory of pitch perception asserts that frequency is coded by the activity level of a sensory neuron. This would mean that a given hair cell would fire action potentials related to the frequency of the sound wave. While this is a very intuitive explanation, we detect such a broad range of frequencies (20–20,000 Hz) that the frequency of action potentials fired by hair cells cannot account for the entire range. Because of properties related to sodium channels on the neuronal membrane that are involved in action potentials, there is a point at which a cell cannot fire any faster (Shamma, 2001).
The place theory of pitch perception suggests that different portions of the basilar membrane are sensitive to sounds of different frequencies. More specifically, the base of the basilar membrane responds best to high frequencies and the tip of the basilar membrane responds best to low frequencies. Therefore, hair cells that are in the base portion would be labeled as high-pitch receptors, while those in the tip of basilar membrane would be labeled as low-pitch receptors (Shamma, 2001).
In reality, both theories explain different aspects of pitch perception. At frequencies up to about 4000 Hz, it is clear that both the rate of action potentials and place contribute to our perception of pitch. However, much higher frequency sounds can only be encoded using place cues (Shamma, 2001).
Sound Localization
The ability to locate sound in our environments is an important part of hearing. Localizing sound could be considered similar to the way that we perceive depth in our visual fields. Like the monocular and binocular cues that provided information about depth, the auditory system uses both monaural (one-eared) and binaural (two-eared) cues to localize sound.
Each pinna interacts with incoming sound waves differently, depending on the sound’s source relative to our bodies. This interaction provides a monaural cue that is helpful in locating sounds that occur above or below and in front or behind us. The sound waves received by your two ears from sounds that come from directly above, below, in front, or behind you would be identical; therefore, monaural cues are essential (Grothe, Pecka, & McAlpine, 2010).
Binaural cues, on the other hand, provide information on the location of a sound along a horizontal axis by relying on differences in patterns of vibration of the eardrum between our two ears. If a sound comes from an off-center location, it creates two types of binaural cues: interaural level differences and interaural timing differences. Interaural level difference refers to the fact that a sound coming from the right side of your body is more intense at your right ear than at your left ear because of the attenuation of the sound wave as it passes through your head. Interaural timing difference refers to the small difference in the time at which a given sound wave arrives at each ear (Figure 5.19). Certain brain areas monitor these differences to construct where along a horizontal axis a sound originates (Grothe et al., 2010).
Deafness is the partial or complete inability to hear. Some people are born without hearing, which is known as congenital deafness. Other people suffer from conductive hearing loss, which is due to a problem delivering sound energy to the cochlea. Causes for conductive hearing loss include blockage of the ear canal, a hole in the tympanic membrane, problems with the ossicles, or fluid in the space between the eardrum and cochlea. Another group of people suffer from sensorineural hearing loss, which is the most common form of hearing loss. Sensorineural hearing loss can be caused by many factors, such as aging, head or acoustic trauma, infections and diseases (such as measles or mumps), medications, environmental effects such as noise exposure (noise-induced hearing loss, as shown in Figure 5.20), tumors, and toxins (such as those found in certain solvents and metals).
When the hearing problem is associated with a failure to transmit neural signals from the cochlea to the brain, it is called sensorineural hearing loss. One disease that results in sensorineural hearing loss is Ménière's disease. Although not well understood, Ménière’s disease results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus (constant ringing or buzzing), vertigo (a sense of spinning), and an increase in pressure within the inner ear (Semaan & Megerian, 2011). This kind of loss cannot be treated with hearing aids, but some individuals might be candidates for a cochlear implant as a treatment option. Cochlear implants are electronic devices that consist of a microphone, a speech processor, and an electrode array. The device receives incoming sound information and directly stimulates the auditory nerve to transmit information to the brain.
Deaf Culture
In the United States and other places around the world, deaf people have their own language, schools, and customs. This is called deaf culture. In the United States, deaf individuals often communicate using American Sign Language (ASL); ASL has no verbal component and is based entirely on visual signs and gestures. The primary mode of communication is signing. One of the values of deaf culture is to continue traditions like using sign language rather than teaching deaf children to try to speak, read lips, or have cochlear implant surgery.
When a child is diagnosed as deaf, parents have difficult decisions to make. Should the child be enrolled in mainstream schools and taught to verbalize and read lips? Or should the child be sent to a school for deaf children to learn ASL and have significant exposure to deaf culture? Do you think there might be differences in the way that parents approach these decisions depending on whether or not they are also deaf?
5.4 TEST YOURSELF
5.5 The Other Senses
LEARNING OBJECCTIVES
By the end of this section, you will be able to:
- Describe the basic functions of the chemical senses
- Explain the basic functions of the somatosensory, nociceptive, and thermoceptive sensory systems
- Describe the basic functions of the vestibular, proprioceptive, and kinesthetic sensory systems
Vision and hearing have received an incredible amount of attention from researchers over the years. While there is still much to be learned about how these sensory systems work, we have a much better understanding of them than of our other sensory modalities. In this section, we will explore our chemical senses (taste and smell) and our body senses (touch, temperature, pain, balance, and body position).
The Chemical Senses
Taste (gustation) and smell (olfaction) are called chemical senses because both have sensory receptors that respond to molecules in the food we eat or in the air we breathe. There is a pronounced interaction between our chemical senses. For example, when we describe the flavor of a given food, we are really referring to both gustatory and olfactory properties of the food working in combination.
Taste (Gustation)
You have learned since elementary school that there are four basic groupings of taste: sweet, salty, sour, and bitter. Research demonstrates, however, that we have at least six taste groupings. Umami is our fifth taste. Umami is actually a Japanese word that roughly translates to yummy, and it is associated with a taste for monosodium glutamate (Kinnamon & Vandenbeuch, 2009). There is also a growing body of experimental evidence suggesting that we possess a taste for the fatty content of a given food (Mizushige, Inoue, & Fushiki, 2007).
Molecules from the food and beverages we consume dissolve in our saliva and interact with taste receptors on our tongue and in our mouth and throat. Taste buds are formed by groupings of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud (Figure 5.21). Taste buds have a life cycle of ten days to two weeks, so even destroying some by burning your tongue won’t have any long-term effect; they just grow right back. Taste molecules bind to receptors on this extension and cause chemical changes within the sensory cell that result in neural impulses being transmitted to the brain via different nerves, depending on where the receptor is located. Taste information is transmitted to the medulla, thalamus, and limbic system, and to the gustatory cortex, which is tucked underneath the overlap between the frontal and temporal lobes (Maffei, Haley, & Fontanini, 2012; Roper, 2013).
Olfactory receptor cells are located in a mucous membrane at the top of the nose. Small hair-like extensions from these receptors serve as the sites for odor molecules dissolved in the mucus to interact with chemical receptors located on these extensions (Figure 5.22). Once an odor molecule has bound a given receptor, chemical changes within the cell result in signals being sent to the olfactory bulb: a bulb-like structure at the tip of the frontal lobe where the olfactory nerves begin. From the olfactory bulb, information is sent to regions of the limbic system and to the primary olfactory cortex, which is located very near the gustatory cortex (Lodovichi & Belluscio, 2012; Spors et al., 2013).
Many species respond to chemical messages, known as pheromones, sent by another individual (Wysocki & Preti, 2004). Pheromonal communication often involves providing information about the reproductive status of a potential mate. So, for example, when a female rat is ready to mate, she secretes pheromonal signals that draw attention from nearby male rats. Pheromonal activation is actually an important component in eliciting sexual behavior in the male rat (Furlow, 1996, 2012; Purvis & Haynes, 1972; Sachs, 1997). There has also been a good deal of research (and controversy) about pheromones in humans (Comfort, 1971; Russell, 1976; Wolfgang-Kimball, 1992; Weller, 1998).
Touch, Thermoception, and Nociception
A number of receptors are distributed throughout the skin to respond to various touch-related stimuli (Figure 5.23). These receptors include Meissner’s corpuscles, Pacinian corpuscles, Merkel’s disks, and Ruffini corpuscles. Meissner’s corpuscles respond to pressure and lower frequency vibrations, and Pacinian corpuscles detect transient pressure and higher frequency vibrations. Merkel’s disks respond to light pressure, while Ruffini corpuscles detect stretch (Abraira & Ginty, 2013).
Pain Perception
Pain is an unpleasant experience that involves both physical and psychological components. Feeling pain is quite adaptive because it makes us aware of an injury, and it motivates us to remove ourselves from the cause of that injury. In addition, pain also makes us less likely to suffer additional injury because we will be gentler with our injured body parts.
Generally speaking, pain can be considered to be neuropathic or inflammatory in nature. Pain that signals some type of tissue damage is known as inflammatory pain. In some situations, pain results from damage to neurons of either the peripheral or central nervous system. As a result, pain signals that are sent to the brain get exaggerated. This type of pain is known as neuropathic pain. Multiple treatment options for pain relief range from relaxation therapy to the use of analgesic medications to deep brain stimulation. The most effective treatment option for a given individual will depend on a number of considerations, including the severity and persistence of the pain and any medical/psychological conditions.
Some individuals are born without the ability to feel pain. This very rare genetic disorder is known as congenital insensitivity to pain (or congenital analgesia). While those with congenital analgesia can detect differences in temperature and pressure, they cannot experience pain. As a result, they often suffer significant injuries. Not surprisingly, individuals suffering from this disorder have much shorter life expectancies due to their injuries and secondary infections of injured sites (U.S. National Library of Medicine, 2013).
The Vestibular Sense, Proprioception, and Kinesthesia
The vestibular sense contributes to our ability to maintain balance and body posture. As Figure 5.24 shows, the major sensory organs (utricle, saccule, and the three semicircular canals) of this system are located next to the cochlea in the inner ear. The vestibular organs are fluid-filled and have hair cells, similar to the ones found in the auditory system, which respond to movement of the head and gravitational forces. When these hair cells are stimulated, they send signals to the brain via the vestibular nerve. Although we may not be consciously aware of our vestibular system’s sensory information under normal circumstances, its importance is apparent when we experience motion sickness and/or dizziness related to infections of the inner ear (Khan & Chang, 2013).
These sensory systems also gather information from receptors that respond to stretch and tension in muscles, joints, skin, and tendons (Lackner & DiZio, 2005; Proske, 2006; Proske & Gandevia, 2012). Proprioceptive and kinesthetic information travels to the brain via the spinal column. Several cortical regions in addition to the cerebellum receive information from and send information to the sensory organs of the proprioceptive and kinesthetic systems.
5.5 TEST YOURSELF
5.6 Gestalt Principles of Perception
LEARNING OBJECTIVES
By the end of this section, you will be able to:
- Explain the figure-ground relationship
- Define Gestalt principles of grouping
- Describe how perceptual set is influenced by an individual’s characteristics and mental state
In the early part of the 20th century, Max Wertheimer published a paper demonstrating that individuals perceived motion in rapidly flickering static images—an insight that came to him as he used a child’s toy tachistoscope. Wertheimer, and his assistants Wolfgang Köhler and Kurt Koffka, who later became his partners, believed that perception involved more than simply combining sensory stimuli. This belief led to a new movement within the field of psychology known as Gestalt psychology. The word gestalt literally means form or pattern, but its use reflects the idea that the whole is different from the sum of its parts. In other words, the brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways. Gestalt psychologists translated these predictable ways into principles by which we organize sensory information. As a result, Gestalt psychology has been extremely influential in the area of sensation and perception (Rock & Palmer, 1990).
One Gestalt principle is the figure-ground relationship. According to this principle, we tend to segment our visual world into figure and ground. Figure is the object or person that is the focus of the visual field, while the ground is the background. As Figure 5.25 shows, our perception can vary tremendously, depending on what is perceived as figure and what is perceived as ground. Presumably, our ability to interpret sensory information depends on what we label as figure and what we label as ground in any particular case, although this assumption has been called into question (Peterson & Gibson, 1994; Vecera & O’Reilly, 1998).
We might also use the principle of similarity to group things in our visual fields. According to this principle, things that are alike tend to be grouped together (Figure 5.27). For example, when watching a football game, we tend to group individuals based on the colors of their uniforms. When watching an offensive drive, we can get a sense of the two teams simply by grouping along this dimension.
According to Gestalt theorists, pattern perception, or our ability to discriminate among different figures and shapes, occurs by following the principles described above. You probably feel fairly certain that your perception accurately matches the real world, but this is not always the case. Our perceptions are based on perceptual hypotheses: educated guesses that we make while interpreting sensory information. These hypotheses are informed by a number of factors, including our personalities, experiences, and expectations. We use these hypotheses to generate our perceptual set. For instance, research has demonstrated that those who are given verbal priming produce a biased interpretation of complex ambiguous figures (Goolkasian & Woodbury, 2010).
DIG DEEPER
The Depths of Perception: Bias, Prejudice, and Cultural Factors
In this chapter, you have learned that perception is a complex process. Built from sensations, but influenced by our own experiences, biases, prejudices, and cultures, perceptions can be very different from person to person. Research suggests that implicit racial prejudice and stereotypes affect perception. For instance, several studies have demonstrated that non-Black participants identify weapons faster and are more likely to identify non-weapons as weapons when the image of the weapon is paired with the image of a Black person (Payne, 2001; Payne, Shimizu, & Jacoby, 2005). Furthermore, White individuals’ decisions to shoot an armed target in a video game is made more quickly when the target is Black (Correll, Park, Judd, & Wittenbrink, 2002; Correll, Urland, & Ito, 2006). This research is important, considering the number of very high-profile cases in the last few decades in which young Blacks were killed by people who claimed to believe that the unarmed individuals were armed and/or represented some threat to their personal safety.
5.6 TEST YOURSELF
Summary
5.1 Sensation versus Perception
Sensation occurs when sensory receptors detect sensory stimuli. Perception involves the organization, interpretation, and conscious experience of those sensations. All sensory systems have both absolute and difference thresholds, which refer to the minimum amount of stimulus energy or the minimum amount of difference in stimulus energy required to be detected about 50% of the time, respectively. Sensory adaptation, selective attention, and signal detection theory can help explain what is perceived and what is not. In addition, our perceptions are affected by a number of factors, including beliefs, values, prejudices, culture, and life experiences.
5.2 Waves and Wavelengths
Both light and sound can be described in terms of wave forms with physical characteristics like amplitude, wavelength, and timbre. Wavelength and frequency are inversely related so that longer waves have lower frequencies, and shorter waves have higher frequencies. In the visual system, a light wave’s wavelength is generally associated with color, and its amplitude is associated with brightness. In the auditory system, a sound’s frequency is associated with pitch, and its amplitude is associated with loudness.
5.3 Vision
Light waves cross the cornea and enter the eye at the pupil. The eye’s lens focuses this light so that the image is focused on a region of the retina known as the fovea. The fovea contains cones that possess high levels of
visual acuity and operate best in bright light conditions. Rods are located throughout the retina and operate best under dim light conditions. Visual information leaves the eye via the optic nerve. Information from each visual field is sent to the opposite side of the brain at the optic chiasm. Visual information then moves through a number of brain sites before reaching the occipital lobe, where it is processed.
Two theories explain color perception. The trichromatic theory asserts that three distinct cone groups are tuned to slightly different wavelengths of light, and it is the combination of activity across these cone types that results in our perception of all the colors we see. The opponent-process theory of color vision asserts that color is processed in opponent pairs and accounts for the interesting phenomenon of a negative afterimage. We perceive depth through a combination of monocular and binocular depth cues.
5.4 Hearing
Sound waves are funneled into the auditory canal and cause vibrations of the eardrum; these vibrations move the ossicles. As the ossicles move, the stapes presses against the oval window of the cochlea, which causes fluid
inside the cochlea to move. As a result, hair cells embedded in the basilar membrane become enlarged, which sends neural impulses to the brain via the auditory nerve.
Pitch perception and sound localization are important aspects of hearing. Our ability to perceive pitch relies on both the firing rate of the hair cells in the basilar membrane as well as their location within the membrane.
In terms of sound localization, both monaural and binaural cues are used to locate where sounds originate in our environment.
Individuals can be born deaf, or they can develop deafness as a result of age, genetic predisposition, and/or environmental causes. Hearing loss that results from a failure of the vibration of the eardrum or the resultant
movement of the ossicles is called conductive hearing loss. Hearing loss that involves a failure of the transmission of auditory nerve impulses to the brain is called sensorineural hearing loss.
5.5 The Other Sense Organs
Taste (gustation) and smell (olfaction) are chemical senses that employ receptors on the tongue and in the nose that bind directly with taste and odor molecules in order to transmit information to the brain for processing. Our ability to perceive touch, temperature, and pain is mediated by a number of receptors and free nerve endings that are distributed throughout the skin and various tissues of the body. The vestibular sense helps us maintain a sense of balance through the response of hair cells in the utricle, saccule, and semicircular canals that respond to changes in head position and gravity. Our proprioceptive and kinesthetic systems provide information about body position and body movement through receptors that detect stretch and tension in the muscles, joints, tendons, and skin of the body.
5.6 Gestalt Principles of Perception
Gestalt theorists have been incredibly influential in the areas of sensation and perception. Gestalt principles such as figure-ground relationship, grouping by proximity or similarity, the law of good continuation, and closure are all used to help explain how we organize sensory information. Our perceptions are not infallible, and they can be influenced by bias, prejudice, and other factors.
Critical Thinking Questions
- Not everything that is sensed is perceived. Do you think there could ever be a case where something could be perceived without being sensed?
- Please generate a novel example of how just noticeable difference can change as a function of stimulus intensity.
- Why do you think other species have such different ranges of sensitivity for both visual and auditory stimuli compared to humans?
- Why do you think humans are especially sensitive to sounds with frequencies that fall in the middle portion of the audible range?
- Compare the two theories of color perception. Are they completely different?
- Color is not a physical property of our environment. What function (if any) do you think color vision serves?
- Given what you’ve read about sound localization, from an evolutionary perspective, how does sound localization facilitate survival?
- How can temporal and place theories both be used to explain our ability to perceive the pitch of sound waves with frequencies up to 4000 Hz?
- Many people experience nausea while traveling in a car, plane, or boat. How might you explain this as a function of sensory interaction?
- If you heard someone say that they would do anything not to feel the pain associated with significant injury, how would you respond given what you’ve just read?
- Do you think a person’s sex influences the way they experience pain? Why do you think this is?
- The central tenet of Gestalt psychology is that the whole is different from the sum of its parts. What does this mean in the context of perception?
- Take a look at the following figure. How might you influence whether people see a duck or a rabbit?
Personal Application Questions
- Think about a time when you failed to notice something around you because your attention was focused elsewhere. If someone pointed it out, were you surprised that you hadn’t noticed it right away?
- If you grew up with a family pet, then you have surely noticed that they often seem to hear things that you don’t hear. Now that you’ve read this section, you probably have some insight as to why this may be. How would you explain this to a friend who never had the opportunity to take a class like this?
- Take a look at a few of your photos or personal works of art. Can you find examples of linear perspective as a potential depth cue?
- If you had to choose to lose either your vision or your hearing, which would you choose and why?
- As mentioned earlier, a food’s flavor represents an interaction of both gustatory and olfactory information. Think about the last time you were seriously congested due to a cold or the flu. What changes did you notice in the flavors of the foods that you ate during this time?
- Have you ever listened to a song on the radio and sung along only to find out later that you have been singing the wrong lyrics? Once you found the correct lyrics, did your perception of the song change?
Access for free at https://openstax.org/books/psychology-2e/pages/1-introduction
what happens when sensory information is detected by a sensory receptor
conversion from sensory stimulus energy to action potential
minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time
messages presented below the threshold of conscious awareness
difference in stimuli required to detect a difference between the stimuli
way that sensory information is interpreted and consciously experienced
system in which perceptions are built from sensory input
interpretation of sensations is influenced by available knowledge, experiences, and thoughts
not perceiving stimuli that remain relatively constant over prolonged periods of time
failure to notice something that is completely visible because of a lack of attention
change in stimulus detection as a function of current mental state
height of a wave
lowest point of a wave
length of a wave from one peak to the next peak
(also, crest) highest point of a wave
number of waves that pass a given point in a given time period
portion of the electromagnetic spectrum that we can see
all the electromagnetic radiation that occurs in our environment
logarithmic unit of sound intensity
sound’s purity
transparent covering over the eye
small opening in the eye through which light passes
colored portion of the eye
curved, transparent structure that provides additional focus for light entering the eye
small indentation in the retina that contains cones
light-sensitive lining of the eye
light-detecting cell
specialized photoreceptors that works best in bright light conditions and detects color
specialized photoreceptor that works well in low light conditions
carries visual information from the retina to the brain
point where we cannot respond to visual information in that portion of the visual field
X-shaped structure that sits just below the brain’s ventral surface; represents the merging of the optic nerves from the two eyes and the separation of information from the two sides of the visual field to the opposite side of the brain
color vision is mediated by the activity across the three groups of cones
color is coded in opponent pairs: black-white, yellow-blue, and red-green
continuation of a visual sensation after removal of the stimulus
ability to perceive depth
cues that relies on the use of both eyes
slightly different view of the world that each eye receives
cue that requires only one eye
perceive depth in an image when two parallel lines seem to converge
visible part of the ear that protrudes from the head
eardrum
middle ear ossicle; also known as the hammer
middle ear ossicle; also known as the anvil
middle ear ossicle; also known as the stirrup
fluid-filled, snail-shaped structure that contains the sensory receptor cells of the auditory system
auditory receptor cells of the inner ear
thin strip of tissue within the cochlea that contains the hair cells which serve as the sensory receptors for the auditory system
perception of a sound’s frequency
sound’s frequency is coded by the activity level of a sensory neuron
different portions of the basilar membrane are sensitive to sounds of different frequencies
one-eared cue to localize sound
two-eared cues to localize sound
partial or complete inability to hear
deafness from birth
failure in the vibration of the eardrum and/or movement of the ossicles
failure to transmit neural signals from the cochlea to the brain
results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus, vertigo, and an increase in pressure within the inner ear
taste for monosodium glutamate
groupings of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud
sensory cell for the olfactory system
bulb-like structure at the tip of the frontal lobe, where the olfactory nerves begin
chemical message sent by another individual
touch receptor that responds to pressure and lower frequency vibrations
touch receptor that detects transient pressure and higher frequency vibrations
touch receptor that responds to light touch
touch receptors that detects stretch
temperature perception
sensory signal indicating potential harm and maybe pain
pain from damage to neurons of either the peripheral or central nervous system
genetic disorder that results in the inability to experience pain
contributes to our ability to maintain balance and body posture
perception of body position
perception of the body’s movement through space
field of psychology based on the idea that the whole is different from the sum of its parts
segmenting our visual world into figure and ground
things that are close to one another tend to be grouped together
things that are alike tend to be grouped together
(also, continuity) we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines
organizing our perceptions into complete objects rather than as a series of parts
ability to discriminate among different figures and shapes
educated guesses used to interpret sensory information | 13,182 | common-pile/pressbooks_filtered | https://fhsu.pressbooks.pub/openstaxpsychologynycctversion/chapter/sensation-and-perception/ | pressbooks | pressbooks-0000.json.gz:44734 | https://fhsu.pressbooks.pub/openstaxpsychologynycctversion/chapter/sensation-and-perception/ |
0FhaS4a9BQUPlf37 | 32.3: Equal and Equivalent | 32.3: Equal and Equivalent
Lesson
Let's use diagrams to figure out which expressions are equivalent and which are just sometimes equal.
Exercise \(\PageIndex{1}\): Algebra Talk: Solving Equations by Seeing Structure
Find a solution to each equation mentally.
\(3+x=8\)
\(10=12-x\)
\(x^{2}=49\)
\(\frac{1}{3}x=6\)
Exercise \(\PageIndex{2}\): Using Diagrams to Show That Expressions are Equivalent
Here is a diagram of \(x+2\) and \(3x\) when \(x\) is \(4\). Notice that the two diagrams are lined up on their left sides.
In each of your drawings below, line up the diagrams on one side.
- Draw a diagram of \(x+2\), and a separate diagram of \(3x\), when \(x\) is \(3\).
- Draw a diagram of \(x+2\), and a separate diagram of \(3x\), when \(x\) is \(2\).
- Draw a diagram of \(x+2\), and a separate diagram of \(3x\), when \(x\) is \(1\).
- Draw a diagram of \(x+2\), and a separate diagram of \(3x\), when \(x\) is \(0\).
- When are \(x+2\) and \(3x\) equal? When are they not equal? Use your diagrams to explain.
- Draw a diagram of \(x+3\), and a separate diagram of \(3+x\).
- When are \(x+3\) and \(3+x\) equal? When are they not equal? Use your diagrams to explain.
Exercise \(\PageIndex{3}\): Identifying Equivalent Expressions
Here is a list of expressions. Find any pairs of expressions that are equivalent. If you get stuck, try reasoning with diagrams.
\(\begin{array}{lllllllll}{a+3}&{\qquad}&{a\div\frac{1}{3}}&{\qquad}&{\frac{1}{3}a}&{\qquad}&{\frac{a}{3}}&{\qquad}&{a}\\{a+a+a}&{\qquad}&{a\cdot 3}&{\qquad}&{3a}&{\qquad}&{1a}&{\qquad}&{3+a}\end{array}\)
Are you ready for more?
Below are four questions about equivalent expressions. For each one:
- Decide whether you think the expressions are equivalent.
- Test your guess by choosing numbers for \(x\) (and \(y\), if needed).
- Are \(\frac{x\cdot x\cdot x\cdot x}{x}\) and \(x\cdot x\cdot x\) equivalent expressions?
- Are \(\frac{x+x+x+x}{x}\) and \(x+x+x\) equivalent expressions?
- Are \(2(x+y)\) and \(2x+2y\) equivalent expressions?
- Are \(2xy\) and \(2x\cdot 2y\) equivalent expressions?
Summary
We can use diagrams showing lengths of rectangles to see when expressions are equal. For example, the expressions \(x+9\) and \(4x\) are equal when \(x\) is \(3\), but are not equal for other values of \(x\).
Sometimes two expressions are equal for only one particular value of their variable. Other times, they seem to be equal no matter what the value of the variable.
Expressions that are always equal for the same value of their variable are called equivalent expressions . However, it would be impossible to test every possible value of the variable. How can we know for sure that expressions are equivalent? We use the meaning of operations and properties of operations to know that expressions are equivalent. Here are some examples:
- \(x+3\) is equivalent to \(3+x\) because of the commutative property of addition.
- \(4\cdot y\) is equivalent to \(y\cdot 4\) because of the commutative property of multiplication.
- \(a+a+a+a+a\) is equivalent to \(5\cdot a\) because adding 5 copies of something is the same as multiplying it by 5.
- \(b\div 3\) is equivalent to \(b\cdot\frac{1}{3}\) because dividing by a number is the same as multiplying by its reciprocal.
In the coming lessons, we will see how another property, the distributive property, can show that expressions are equivalent.
Glossary Entries
Definition: Equivalent Expressions
Equivalent expressions are always equal to each other. If the expressions have variables, they are equal whenever the same value is used for the variable in each expression.
For example, \(3x+4x\) is equivalent to \(5x+2x\). No matter what value we use for \(x\), these expressions are always equal. When \(x\) is 3, both expressions equal 21. When \(x\) is 10, both expressions equal 70.
Practice
Exercise \(\PageIndex{4}\)
- Draw a diagram of \(x+3\) and a diagram of \(2x\) when \(x\) is \(1\).
- Draw a diagram of \(x+3\) and of \(2x\) when \(x\) is \(2\).
- Draw a diagram of \(x+3\) and of \(2x\) when \(x\) is \(3\).
- Draw a diagram of \(x+3\) and of \(2x\) when \(x\) is \(4\).
- When are \(x+3\) and \(2x\) equal? When are they not equal? Use your diagrams to explain.
Exercise \(\PageIndex{5}\)
- Do \(4x\) and \(15+x\) have the same value when \(x\) is \(5\)?
- Are \(4x\) and \(15+x\) equivalent expressions? Explain your reasoning.
Exercise \(\PageIndex{6}\)
- Check that \(2b+b\) and \(3b\) have the same value when \(b\) is 1, 2, and 3.
- Do \(2b+b\) and \(3b\) have the same value for all values of \(b\)? Explain your reasoning.
- Are \(2b+b\) and \(3b\) equivalent expressions?
Exercise \(\PageIndex{7}\)
80% of \(x\) is equal to 100.
- Write an equation that shows the relationship of 80%, \(x\), and 100.
- Use your equation to find \(x\).
(From Unit 6.2.2)
Exercise \(\PageIndex{8}\)
For each story problem, write an equation to represent the problem and then solve the equation. Be sure to explain the meaning of any variables you use.
- Jada’s dog was \(5\frac{1}{2}\) inches tall when it was a puppy. Now her dog is \(14\frac{1}{2}\) inches taller than that. How tall is Jada’s dog now?
- Lin picked \(9\frac{3}{4}\) pounds of apples, which was 3 times the weight of the apples Andre picked. How many pounds of apples did Andre pick?
(From Unit 6.1.5)
Exercise \(\PageIndex{9}\)
Find these products.
- \((2.3)\cdot (1.4)\)
- \((1.72)\cdot (2.6)\)
- \((18.2)\cdot (0.2)\)
- \(15\cdot (1.2)\)
(From Unit 5.3.4)
Exercise \(\PageIndex{10}\)
Calculate \(141.75\div 2.5\) using a method of your choice. Show or explain your reasoning.
(From Unit 5.4.5) | 1,141 | common-pile/libretexts_filtered | https://math.libretexts.org/Bookshelves/Arithmetic_and_Basic_Math/Basic_Math_(Grade_6)/06%3A_Expressions_and_Equations/32%3A_Equal_and_Equivalent/32.03%3A_Equal_and_Equivalent | libretexts | libretexts-0000.json.gz:21459 | https://math.libretexts.org/Bookshelves/Arithmetic_and_Basic_Math/Basic_Math_(Grade_6)/06%3A_Expressions_and_Equations/32%3A_Equal_and_Equivalent/32.03%3A_Equal_and_Equivalent |
ilENGSqDBgL6Qg8w | A first book in psychology, by Mary Whiton Calkins. | Norwood, Mass., U.S.A.
MIHI CARISSIMAE AD CARMINA CONDENDA CONSILIA PRAEBENDA SOLATIA ADFERENDA NATAE HUNC LIBRUM QUAMVIS EA INDIGNUM ANIMO AMANTISSIMO DEDICAVI
PREFACE
This book has been written in the ever strengthening conviction that psychology is most naturally, consistently, and effectively treated as a study of conscious selves in relation to other selves and to external objects — in a word, to their environment, personal and impersonal. However he defines his science, every psychologist talks and writes about selves — of myself and yourself — as conscious of people, of things, or of laws and formulas. The psychology of self, which this book sets forth, is a conscious adoption and scientific exposition of this natural and practically inevitable conception.
The book differs in several ways from its predecessor, " An Introduction to Psychology." In general, I have tried to make a simpler, directer approach to the subject. In the earlier book, I treated psychology in a twofold fashion, both as science of selves and as science of ideas (or 'mental processes '), discussing all forms of consciousness from both points of view. I have here abandoned this double treatment, with the intent to simplify exposition, not because I doubt the validity of psychology as study of ideas, but because I question the significance and the adequacy, and deprecate the abstractness, of the science thus conceived. In a second fashion this book differs from the other. I have tried to embody what appear to me to be the important results of so-called functional psychology. That is to say, I have taken explicit account of the charac-
teristic bodily reactions on environment wliich accompany perception, thought, emotion, and will ; and I have briefly considered the various forms of consciousness as factors in conduct, and as significant in individual and in social development. The order of topics has been radically changed. I have included in the Appendix the sections on the physiology of nervous system and sense organs, and on abnormal consciousness, as well as the brief discussions of moot points in psychology. The consideration of the different classes of elements of consciousness instead of being massed together at the beginning of the book, have been introduced singly, as subordinate parts of the chapters, or groups of chapters, on perception and imagination, recognition, and thought, emotion and will.
This is, then, a new book, not the condensation of an old one ; yet it does not teach a new form of psychology. The same conception of psychology underlies the two ; and I have not scrupled to transfer, though seldom without some change, pages, paragraphs, and sentences from the earlier book.
Time would fail me to name all the people whose help in the preparation of this book I gratefully remember. My greatest indebtedness is to Professor Eleanor A. McC. Gamble, for her discriminating criticism of the book as a whole. My warm thanks are due, also, to my colleague. Dr. Helen Dodd Cook, and to my former colleague. Professor L. W. Cole, for their critical reading of portions of the text. And I am glad of this opportunity to acknowledge the expert assistance of Miss Helen G. Hood, who has prepared the Index.
II. The Affective Elements 369
a. (§ 2). Stump 's Doctrine of 'Pleasantness' and 'Unpleasantness' as Sensational. (With bibliography) . . 369 ^- (§ 3)' Wundt's Tridimensional Theory of the Affections.
I. The Nature of Psychology
Psychology may be defined provisionally as science of consciousness— ^of perception, memory, emotion, and the like. Many psychologists find this definition sufficient as it stands, but, in the view of the writer of this book, it docs not go far enough. For consciousness does not occur impersonally. Consciousness, on the contrary, always is a somebody-being-conscious. There is never perception without a somebody who perceives, and there never is thinking unless some one thinks. Bearing this fact in mind, we may define psychology more exactly by naming it science of the self as conscious.^
Either definition leads at once to a consideration of the meaning of the word 'science.' The scientist is distinguished from the ordinary observer in that he describes exactly and, if possible, explains the objects which both observe. Exact description includes, first, analysis and, second, classification through observed likenesses and differences; explanation consists in linking one fact to allied facts of its own or of another order. A scientist, for example, and an unscientific
* Cf. Appendix, Section I. (§ i). Throughout the book these numerical exponents, beginning anew in each chapter and not always consecutive, refer to the divisions (§§) of a section in the Appendix numbered to correspond with the given chapter.
2 A First Book in Psychology
observer pick up, each, a stone from the roadside. The latter will tell you that he has found a big, smooth, gray stone. The former describes his stone as a smoothed and striated boulder of granite, rich in mica, and explains it as dropped from some glacier. Similarly, the unscientific observer of consciousness tells you that he better remembers Booth's Hamlet than Patti's Lucia. His psychologically trained friend will describe the memory of Hamlet as a case of visual imagination, distinguishing it as more intense than the auditory imagination of Patti's singing; and will explain the difference as due to the fact that he has been trained to draw, whereas he does not know one note from another. In a word, the scientist in each of these cases first describes phenomena, that is, observes them analytically, compares, and classifies them; and he next seeks, if he can, to explain phenomena — in these cases, the stone by the roadside and the vivid memory.
This attempt to distinguish science from everyday observation must be followed by an effort to mark off science from philosophy, for the psychologist, it must be confessed, is sometimes tempted to overstep the border. In brief, the distinction is this : philosophy seeks to discover the ultimate or irreducible nature of any (or of all) reality, whereas a science voluntarily limits itself to one group of facts, takes for granted the existence of coordinate groups, and does not seek to reduce one to the other or both to any deeper kind of reality. The philosopher, for example, asks whether mind is a function of matter, or matter an expression of mind, or whether both are manifestations of a more ultimate reality, whereas the psychologist takes for granted, on the basis of ordinary observation, that minds and material objects exist.
conscious; and we rightly therefore ask for a further description, even if only a jjreHminary description, of the self. The conscious self of each one of us is not a reality which is merely inferred to exist: it is immediately experienced as possessed of at least four fundamental characters. The self as immediately experienced is (i) relatively persistent — in other words, I am in some sense the same as my childhood self; is (2) complex — I am a perceiving, remembering, feeling, willing self; is (3) a unique, an irreplaceable self — I am closely like father, brother, or friend, but I am, after all, only myself : there is only one of me. The self is experienced finally (4) as related to objects which are either personal or impersonal. For example, I am fond of my mother (relation to a personal object) and I am tasting an orange (relation to an impersonal object).
As the last sentences have indicated, a person or an impersonal fact, to which the self is related, is called its object — that of wdiich it is conscious.^ And every such object, whether personal or impersonal, may be further distinguished as either private or public (common) object. The common, or public, personal object of any self is some other self. For example. President Taft, as he greets me at a White House reception, is my personal object — but my common, not my private or peculiar object, since the sight of him is shared by all the other people in the line behind me. When, on the other hand, I am conscious of myself as, for instance, enchanted to meet the President — I am my own personal and private object; that is to say, I am conscious of myself in a peculiar w^ay in which no one else is conscious of me. Within the class, also, of impersonal objects a distinction may be made between private and common objects,
that is, l)et\vccn (a) my experiences — my feelings, for cxami)lc — regardctl as ])eculiarly mine and (b) impersonal objects of anybody's consciousness, such as chemical formuhe and sidewalks. And there is, finally, the important distinction between externalized and non-externalized impersonal objects. Thus, the sidewalk is an externalized object, that is, it is conceived as if independent of any and of all selves. On the other hand, neither my feeling, a private impersonal object, nor the chemical formula, a common object, is externalized. Rather, each is realized as experience — the feeling as the experience which one self has, the formula as the common experience of many selves. It should be added that I am always, inattentively or attentively, conscious of the private, personal object, myself, whatever the other objects of my consciousness.
The establishment of these distinctions between objects of consciousness serves thus to differentiate groups of sciences. It appears that psychology deals with 'private objects,' primarily with my particular, intimately known 'own self,' but
also with percepts, thoughts, and feelings as they appear to me and to nobody else. The concern of sociology on the other hand is with selves as common, or universal, phenomena, objects of anybody's consciousness; and logic and mathematics deal with thoughts — with arithmetical rules and logical axioms, for example — which are public property, parts of common experience. Sharply distinguished from all these are the physical sciences which concern themselves with externalized objects — with plants, animals, stones, acids, falling bodies. Psychology, to be sure, since its object — the self — is related to objects of every sort, takes account of all these objects of the other sciences ; that is to say, I — as psychologist — study myself as related to other self, to universal principle or thought, and to external object; but psychology has to do with all these objects not in themselves but only in relation to the ' myself.' Sometimes, indeed, the word ' object ' is narrowed so as to apply only to impersonal objects of one class or another, and not to the self.
It must be pointed out that certain real difficulties attend this classification of the self's objects. There is, first, the difficulty of conceiving the self as both subject and object. And there is, second, the difficulty in\-olved in conceiving the 'thing,' the externalized object, as independent of all selves, when yet the self is related to it and conscious of it. But both these are difficulties only for the metaphysician. The psychologist who, like every scientist, must accept certain facts, without looking for their ultimate explanation, rests in the first case on the immediate certainty that I am conscious of myself. He avoids the second difficulty in that he does not assert that external objects, independent of all sehes, really exist. He teaches merely
of such independent objects.
This account, brief as it is, of the self as related, provides the outline for our study of psychology. The chapters which follow will develop these distinctions. They will include also some attempt to explain these facts of psychology ; and in the effort to explain they will range beyond the domain of psychology proper and will look for facts of physics, of biology, and of physiology, for phenomena of vibration, of adaptation, of anatomical structure, with which to link the psychic changes.
The methods of psychology are, in general, the two methods of every science : description (that is, analysis and classification) and explanation. But besides these fundamental forms of procedure, every science has certain methods peculiar to itself; and the method which distinguishes psychology is that of introspection. This follows directly from what has been said of the subject-matter of psychology. Its facts are not the common, independent, externalized facts of the physical sciences, but the inner facts, selves, and ideas. To observe the psychic fact one has not, therefore, to sweep the heavens with a telescope, nor to travel about in search of rare geological formations ; but one has merely to ask oneself such questions as: "How do I actually feel?" "What do I mean when I say that I perceive, remember, believe?"
The method has obvious advantages. It makes no especial conditions of time and place; it requires no mechanical adjunct; it demands no difficult search for suitable material; at any moment, in all surroundings, with no external outfit,
The Methods of Psychology 7
one may study the rich material provided by every imaginable experience. In an extreme sense, all is grist that comes to the psychologist's mill. The apparent facility of introspection is, however, one of its greatest dangers. Nothing seems easier than to render to ourselves a true account of what goes on in our consciousness. We are tempted, therefore, to overlook the need of training in introspection and to minimize its characteristic difficulties. Chief among these is the change which it makes in its own object. To attend to a particular experience actually alters it. If I ask myself in the midst of a hearty laugh, "Just what is this feeling of amusement?" forthwith the feeling has vanished, and a strenuous, serious mood has taken its place. Much the same is true of every form of consciousness. To observe myself perceiving, remembering, or judging is no longer simply to perceive, to remember, and to judge, but to reflect upon perception, memory, and judgment. It is true, therefore, as many psychologists have shown, that introspection is never of the immediate present, but is rather a case of memory, and subject, therefore, to all the uncertainties of memory.
The verification of our introspection is best secured by an important subsidiary method shared by psychology with many of the physical sciences — the method of experiment. To experiment is to regulate artificially the conditions of phenomena in such wise as to repeat, to isolate, and to vary them at will. In a multitude of ways, therefore, experiment aids scientific observation. Repetition of phenomena insures accuracy of analysis, and makes it possible to verify the results of a single observation ; isolation of conditions narrows the object of study, and avoids the distraction of the observer's attention ; and, finally, variation of conditions makes
it possible to cx])lain a j)hcnomcnon exactly, by connectin;^ it with those conditions only which it always accompanies. But because psychic facts differ from i)hysical phenomena in that they can never be repeated or exactly measured, psychological experiment directly concerns itself with the physical stimulation of psychic facts and with the physical reactions to these stimuli. For example, though I cannot measure the vividness of a memory image, I can count the number of repetitions of a series of words which I read aloud to the person on whom I experiment; and I can compare the number of errors he makes in repeating the word-series when he has heard it once only, three times, or five times. In this way I can gain, experimentally, a conclusion about the relation of memory to frequency of experience, and by repeating the experiment many times with the same individual and with others, I may arrive at some trustworthy general conclusion.
This chapter has so far dealt, as this book will mainly deal, with the fundamental form of psychology — normal, introspective psychology, the scientific study of oneself being conscious. Based on this introspective study is a second important, though subsidiary, branch of the science, comparative or inferential jjsychology, the science of inference from the structure or from the behavior of living organisms, human or merely animal, to the nature of other selves. The objects of normal comparative psychology are animals, children, and primitive men. Its methods are the careful observation of the words or actions of the animals and people whom it studies, and the inference of the conscious exi^ericnccs which underlie these outer manifestations. Such inference
involves introspection, because it consists in attributing one's own experience, under given circumstances, to other selves; but this introspection, because imputed to others, has not the same value as the study of one's own consciousness. Yet comparative studies of structure and of behavior have usefully directed introspection and have richly contributed to the explanatory side of psychology. The following summary enumerates these different forms of psychology : —
A final question still calls for a provisional answer, the question: Of what special use is the study of psychology? The technical psychologist may be tempted to ignore the question on the ground that it should never have been asked, that — rather — the student must assume at the outset the essential imj)ortance of all study, the vital significance of knowing anything. But the psychologist, in our sense of the term, has no need to take this ground. He studies the related self; and human conduct is the acti\'e relation of self to other
selves. A deeper acc^uaintance with my own nature may surely, therefore, have a significant inllucnce on my behavior. True, the study of behavior as such belongs to ethics and to pedagogy rather than to psychology ; but in studying psychology one may keep in mind the bearing of the science upon practical problems. In more concrete terms : the study of psychology is practically useful in so far as it aids me, on the one hand, to preserve and to develop myself, and, on the other hand, effectively to influence my environment.
Related Self
What am I at this present moment ? I am a self, conscious of holding a blue celluloid pen, of looking down upon a white page, of hearing " The Road to Mandalay " whistled by a man who is mowing beneath my window, conscious also of the fragrance of the freshly cut grass and the warmth of the day, and, all the while, imagining a Tyrolese mountain landscape which I have never seen, I am, in other words, a perceiving and imagining self, and though this is certainly no exhaustive account of me, still I may well attempt no more, at this stage of my psychologizing, than the close description and the explanation of perception and imagination, the experiences so far enumerated in the self of the present.*
It will be convenient to begin with the analysis of perception. I notice first that in perceiving pen, paper, and tune I am directly aware of a certain inevitableness and involuntariness in the experience. I must see and touch just this pen; I can-
* Before reading further, and without consulting any book, the student should state, in writing, all the likenesses and the differences which he can observe between (i) his experience as he perceives the desk (or rug, or hat) at which he is looking, and (2) his experience as he imagines a similar desk (rug, or hat) in some other room. The record of this introspection may profitably be compared with that of other students.
not hclj) feeling warm; I must hear this tune and must smell the odor of the falling grass. I may wish that I held a silver pen, that I were cool, not warm, that I were smelling roses instead of hay; but I am bound down, in my perceiving, to precisely this experience. I am, in a word, directly conscious of myself as receptive. And this direct consciousness of receptivity, prominent in my perception, is wanting to my imagination. In some sense, at least, my imaginings are under my own control. In the present case, for example, I can turn from the inner contemplation of the mountain view to the imagining — let us say — of the prosaic interior of a German psychological laboratory.
A second significant difference between perceiving and imagining is revealed not of necessity during the perception, but as I reflect on it or look back on it. To such reflective observation it is evident that my perception has been shared, or at any rate that it might have been shared, by other selves ; whereas I need not, unless I will, share my imaginings. For example, the housemaid dusting the room can see my blue pen and white paper, can hear the whistled melody, and smell the hay and feel the warmth. But the housemaid does not share my imagination of the Tyrolese mountains any more than I read the imagination which has brought a smile to her lips. People share our imaginings in a sense, when they try to reproduce them, yet, evidently, the world of imagination has a privacy foreign to the common world of our j^erceptions.
From this privacy of imagination follows a third dift'erence. It is this : perception is reflectively regarded as my consciousness of relation to an external or ' independent' object, whereas the object of imagination, though impersonal, is not externalized. The object of i)erception is thus, from the point of
Perception and Imagination 13
view of the j')sychologist, the external [)en or mowing-machine, whereas the object of imagination is no external object, but rather the mere image of landscape or of harmony.
Three differences have thus been emphasized as distinguishing perception from imagination : (i) my immediately realized receptivity, or passivity, in perceiving; (2) the reflectively realized community of my perception with the experience of other selves; (3) my relation in perception to an object which I regard as independent and external. But these distinctions must not obscure the likenesses. Perception resembles imagination in at least three ways, (i) Both are known (to reflection, if not immediately) as impersonal consciousness, in the sense that in perceiving and imagining I am not predominantly conscious of selves. I perceive or imagine pen, paper, tune, but I do not perceive or imagine you or myself. In the second place, (2) both perception and imagination are forms of particularizing consciousness. I do not, for example, perceive or imagine pens in general, or even the class of celluloid pens, but rather this particular, individual pen. A final, highly important likeness of perception and imagination is the following : (3) Both are chiefly sensational experiences concerned with vision, touch, and hearing rather than with feeling or with the consciousness of relation. This consideration will lead us to a psychological analysis difl"erent from that already attempted. It is expedient, therefore, to summarize our results. Perception has been described as sensational, passive, impersonal, externalizing, and particularizing consciousness reflectively realized as common to other selves. Imagination has been described as sensational, im[)ersonal, and particularizing, but as lacking the consciousness of passivity, of externality,
The conscious self is, as we have seen, persistent, unique, related, and complex. If now we arbitrarily drop out of account the persistence, the uniqueness, and even the rclatcdness, we are still conscious of complexity. The mental reduction of this complex experience to its lowest terms gives what are called the structural elements of consciousness. These apparently irreducible constituents seem to fall into three main classes which have been called 'sensational' (or 'substantive')*; (2) 'attributive' (sometimes called by the name of the chief subclass 'affective' elements); and (3) 'relational.' To illustrate from the experience which we are studying : My consciousness of blueness is a sensational element ; my consciousness of the unpleasantness of the warm day is an affective element ; and, finally, my consciousness of the contrast between the blue of the pen handle and the blue of my account-book cover is a relational experience. It is evident that my experiences may be distinguished according as one or other of these elemental kinds of consciousness predominates ; and jt is equally evident that, from this point of view, perception and imagination are both chiefly sensational in character, distinguished mainly as the consciousness of colors, sounds, and fragrances.
Between perception and imagination as sensational complexes three further distinctions may ordinarily be made. If I close my eyes, and then imagine the oval gilt frame
which stands on my desk, and if I then reopen my eyes and compare perception with imagination, I shall find that the im agination differs from the perception, first, in that it is sensationally less intense — the gilt of the imaged frame is duller; second, in that it is less complex — I lack altogether the consciousness of certain details of the frame; and finally, in that it is more evanescent, more readily displaced by other imaginings. And yet there are cases of imagination which lack one or more of these characteristics. The perception of one's bodily attitude, for example, may be less intense, less accurate, and less permanent than the visual imagination of a face or the auditory imagination of a melody ; one's perception of an unknown substance, which one merely tastes or smells, may be less vivid, also, than one's visual imagination of a bowl of strawberries or of a roasted duck, ' All this proves thai intensity, detail, and stability are merely common and not necessary characteristics of perception. Indeed, the only invariable distinctions are those enumerated in the preceding section of this chapter.
In perception and in imagination alike, my sensational experiences are of different sorts : I see, hear, smell, and touch. And one way of classifying both perception and imagination is according to predominant sense-elements. Such a classification is, however, of most significance as applied to imagination, for, as has appeared, my imagination is in some degree controllable ; and I may therefore make practical use of the discovery that my imagination is chiefly visual or auditory. In what follows we shall study imagination as sensational, but we must remind ourselves that all the distinctions which arc made are equally, though less fruitfully, ajjplicable to perception.
("oncretc imagination — that is to say, the imagination ol things, scenes, and events — must, in the first jjlace, he (Hstinguishcd from merely verbal imagination. Concrete imagination may belong to any sense-order, but it is in the main cither visual, auditory, or tactual; or else it belongs to a 'mixed' tyi)e, including elements of several kinds. Every student of j)sychology should undertake an introspective study of the sense-type of his imagination by the use of some such questionary as the following : * —
4. The crack of a whip.
* Condensed from a questionary formulated by Professor Gamble and used in the Wellesley College Laboratory since 1898-1899. These questions should be answered, in writing, before the student reads further.
10. The taste of salt.
It is obvious that one who 'sees' the pink and green anrl shape of the rose has a visual imagination, and that visual imaginations differ according as colors or forms arc more distinctly visualized. The person with auditory imagination can 'hear' the sound of the organ and the crack of the whip; and, in similar fashion, the other types of concrete imagination are tested by these questions. It should be noted that, in many experiences, visual imagination supplements the perception of pressure and of sound, as when we 'localize' a touch by imagining the look of wrist or of forehead, on which it falls, or imagine the puffing red motor-car at sound of its bell.
There is no character in which individuals differ more widely than in the prevailing sense-type of their imagination. In recalling, for example, the balcony scene in " Romeo and Juliet," some people see with the eye of the mind the shadowy form_ of Romeo and the figure of Juliet, clear-cut against the lighted window, the 'stony limits,' the cypresses, statues, and fountains of the Italian garden, and the "blessed moon . . . that tips with silver all these fruit-tree tops"; others, like Juliet, may "know the sound of that tongue's utterance," and may hear, in imagination, Romeo's deep-voiced lovemaking and the "silver-sweet sound" of Juliet's replies "like softest music to attending ears." Still others, finally, may image Romeo's movements as "with love's light wings" he " did o'erperch these walls."
The study of an imaginative writer often reveals the predominant sense-order of his imagination. His pages may glow with color or thrill with music or (juiver with rhythmic motion. The blind poet, Philip Bourke ISIarston, for example, describes a garden ravaged by "winds in the night, without pity or pardon," in verses which contain no colorword, though they make mention of the garden's 'scent and sound,' and arc full of striking images of pressure and of cold : —
forest, swept by the
"... wild West Wind, thou breath of Autumn's being. Thou, from whose unseen presence the leaves dead Are driven, like ghosts from an enchanter fleeing, Yellow, and black, and pale, and hectic red."
Sometimes, indeed, a poet's lines seem to disclose to us his peculiar delight in special colors or sounds. So Shelley, once more, seems most readily to imagine the greens and
to clouds " fleck'd with fire and azure." Even his gardens are full of "tender blue bells," of "flowers azure, black, and streak'd with gold," and of "broad flag-flowers, purple prank'd with white."
v The most common type of concrete imagination probably is the visual, for, in spite of individual differences, most people can imagine objects in some vague outline and in some dull color. Every sculptor, painter, or architect who sees his vision before he embodies it has \'isual imagination. The inventor also 'sees' his engine or his dynamo in all its parts and connections, before he enters upon the actual construction of it; and the well-dressed woman sees the end from the beginning, the completed gown within the shapeless fabric. Above all, visual imagination is the endowment of the geometer and of the scientist. The one imagines the projections and intersections of lines and planes; the other beholds the planets
moving in tlicir courses, pcojjlcs the earlli with the forms of animals long extinct, or makes of every common object a palpitating dance of atoms and subatoms. Even a poet's imagination may hesitate before the challenging hypotheses of science, for it is said that Wordsworth once exclaimed, "I have not enough imagination to become a geologist."
Yet in spite of the value of visual images to artists, inventors, and mathematicians, it must at once be acknowledged that, even to them, the visual type of imagination is not indispensable, but that it may be replaced by what we know as the j;actual-motor tyi:)c, the imaging of the movements by which one traces the outlines of figures or of designs. Galton found, as result of careful inquiry, that "men who declare tliemselves entirely deficient in the power of seeing mental ])ictures — can become painters of the rank of Royal Academicians." And James says of himself, "I am a good draughtsman and have a very lively interest in pictures, statues, architecture, and decoration, and a keen sensibility to artistic effects. But I am an extremely poor visualizer, and find myself often unable to reproduce in my mind's eye pictures which I have most carefully examined." * In these cases, a quickness to recognize and to discriminate colors and forms is combined with the inability to imagine them. Evidently, visual imagination is here replaced by pressure imagination — imagination of the motions necessary to the production of sculpture, machine, or figure : a sculptor of this type reproduces in imagination the movements of his chisel, and the geometrician draws his figure or indicates by imaged movements the sweep of orbits and the intersection of lines.
imagination.* He tested the color-imagery of several students by pronouncing in a darkened room the names of colors and requiring them to describe the resulting experiences. One of these young men proved utterly incapable, with the strongest effort, of imagining any color whatever. Another historic exami)le is Charcot's patient, a man whose visual imagery was impaired through nervous disease. "Asked to draw an arcade, he says, ' I remember that it contains semicircular arches, that two of them meeting at an angle make a vault, but how it looks I am absolutely unable to imagine.' . . . He complains of his loss of feeling for colors. 'My wife has black hair, this I know; but I can no more recall its color than I can her person and features !'" f
The auditory type of imagination is unquestionably less common than the \'isual, and it is almost always closely combined with imagery of the motor-tactual sort. It is the imagetype of the great musicians, of Beethoven, for exami)le, who composed his symphonies when totally unable to hear a note of them. But though less significant to most of us than the visual images, the concrete auditory imagination belongs, at least in some degree, to all people who are able to recall voices and melodies. The prevalence of auditory imagery is suggested by the ordinary ruse of violin players, who produce the effect of a diminuendo, lengthened beyond the actual sound, by continuing the drawing motion of the bow when it no longer touches the string.
The most significant type of tactual (or pressure) imagination is frequently called the tactual-motor type — the imagination of the pressures, often internal, which are originally
due to bodily movements; the imagination, for example, of one's shortened breath as one is running. Imagination may be, also, of some other dermal sense-type, that is, of pain, of warmth, or of cold. Such experiences are perhaps rare, but they unquestionably occur. Keats, for example, vividly images the coldness of
One must carefully distinguish between such imagining and the corresponding peripherally aroused sensation. The vivid account of a wound or a physical injury may excite, through the connection of cortical neurones through motor neurones with organic reactions, the actual, visceral pressuresensations which constitute the feeling of faintness, and it may even excite the pain end-organs. In the same way, I grow actually hot over a remembered mortification and I shiver with cold at a revived fear.
Smell and taste imagination are relatively infrequent and their occurrence is, indeed, often denied. It is said that when we imagine objects fragrant in themselves, such as roses or cheese or coffee, we imagine their look or their feel without imagining their odor; and that when we suppose ourselves to imagine tastes, we are really imagining the colors and the forms of food. It will be admitted that from our dream dinners we are apt to wake before tasting anything, and that poetic descriptions of banquets dwell chiefly on the color of 'dusky loaf of 'golden yolks' and 'lucent s}Tops,' and on the texture of 'fruit . . . rough or smooth rined' or of 'jellies soother than the creamy curd' ! Yet no one will deny that the poet must have imagined odors, and not colors , when he writes in the fifth stanza of the '' Ode to a Nightingale" : —
Besides this unintended evidence from imaginative writers we have well-attested instances of the smell and taste imagination, both in waking experience and in dreams, of well-trained observers. An inquiry among fifty Wellesley College students, somewhat trained in introspection, disclosed the fact that thirty-one were sure that they could imagine the odors of certain substances, such as burning tar, burning sulphur, and mignonette.
More common than any of these classes of concrete imagination is that to which we ha\e already referred as the 'mixed type.' The imagination of any object is likely, in other words, to include elements of more than one senseorder : it is not wholly visual and still less is it entirely auditory or tactual. Either the visual or auditory elements may predominate, l)Ut the imagination — of a dinner-party, for example — is rarely a mere complex of the colors and forms of dresses, faces, candles, flowers, foods, nor yet of the sounds of conversation, laughter, and service, but it includes both visual and au(Htory images, perhaps with a pressure image also of the 'feel' of linen or of siher, and a gustatory or olfactory image of the taste of beef or the odor of roses.
one, save the ])sychologist, realizes. Tn the exj)ericnce of many people these altogether crowd out concrete imaginings. We suppose ourselves to be imagining the Heraion at Argos, the "Madonna della Sedia," or Liszt's "Hungarian Rhapsod}-," when, as a matter of fact, we are mainly saying to ourselves the words 'Heraion,' 'madonna,' 'rhapsody.' Of course this is an artificial state of affairs. Words are conventional symbols, not instinctive reactions; they play no part at all in the imaginative life of animal or of baby, and little part in that of the savage. The civilized being, however, is born into a world of people whose most characteristic activity is neither eating, walking, nor fighting, but talking. At first, through pure imitation, and afterwards because he recognizes the utility of language, he largely occupies himself with words, first heard and spoken, and later read and written. And as habits fall away through disuse, so, little by little, in the experience of most of us, word-images take the place of concreter images of color, sound, and the like. It is unnecessary to dwell on the immense utility of verbal imagination, for we are already victims of what Mr. Garrison calls 'the ignorant prejudice in favor of reading and writing,' and, he might have added, 'of talking.' Words serve not only as the means of communication, and thus as the surest method of social development, but — by their abstract, conventional form — as an aid to rapid memorizing and to clear reasoning; they are indispensable parts of our intellectual equipment; yet they are in themselves but poor and insignificant experiences, and they work us irreparable harm if they banish, from the life of our imagination, the warm colors, broad spaces, liquid sounds, and subtle fragrances which might enrich and widen our experience.
Verbal Imagination 25
We have ample proof that this is no purely fictitious danger. Gallon's most significant conclusion from his statistical study of imagination is that the "faculty of seeing pictures, . . . if ever possessed by men of highly generalized and abstract thought, is very aj)t to be lost by disuse." Many of the ' men of science,' whose imagination he tested, had "no more notion" of the nature of visual imagery "than a color-blind man . . . has of the nature of color. ' It is only by a figure of speech,'" one of them says, "'that I can describe my recollection of a scene as a mental image that I can see with my mind's eye, ... I do not see it . . . any more than a man sees the thousand lines of Sophokles which under due pressure he is ready to repeat.' " Every mixed figure is in truth a witness to the common lack of concrete imagery. The earnest preacher who exhorted his hearers to water the sparks of grace, and the fervid orator who bewailed the cup of Ireland's misery as 'long running over, but not yet full,' were, of course, without the visual images which their words should suggest. Doubtless, most of their hearers received these astounding statements without a quiver of amusement — not, j)rimarily, because they lacked a sense of humor, but because they failed to translate the words into visual imagery.
The study of the varying forms of verbal imagination discloses the fact that, like the forms of concrete imagination, they belong usually to a visual, an auditory, a tactual, or a 'mixed' class, though they may conceivably be of other sense-types. The good visualizer images his words as they are printed on a page, reading them off, sentence by sentence or verse by verse, recalling the precise part of the page on which a given word or sentence appears. Galton tells of a statesman who sometimes hesitates in the midst of a speech, because
plagued by the image of his manuscript speech with its original erasures and corrections. Even musicians may be helped by symbolic imagery and may play by mentally reading their scores. Again, verbal imagination may be of words as heard ; and such masters of musical verse as Sophokles, Tennyson, and Swinburne must have auditory verbal imagery. One may 'hear' words spoken by oneself or by others, one may listen in imagination to conversations between different people, or one may recall whole scenes of a play in the characteristic intonations of different actors. '"When I write a scene,' said Legouve to Scribe,* 'I hear but you sec. In each phrase which I write, the voice of the personage who speaks strikes my ear. Vous qui etes le theatre meme your actors walk, gesticulate before your eyes; I am a listener, you a spectator.^ 'Nothing more true,' said Scribe; 'do you know where I am when I write a piece? In the middle of the parterre.'"
One's verbal imagery, finally, may be of the tactual-motor type; one may imagine oneself as speaking, or, less often, as writing the words. A simple proof of the frequent occurrence of these motor images was suggested by Dr. Strieker : f the attempt to imagine a word containing several labials — such a word as 'bob' or 'pepper' — without the faintest imaged or actual movement of the lips. Most people will be unsuccessful in such an experiment, which brings to light the presence, in verbal imagining, of the imagination or perception of movements of the throat and lips. Even the distinct effort to visualize words may result in tactualmotor images. James, for example, "can seldom call to
The various phenomena of aphasia, the cerebral disease affecting the word-consciousness, confirm tlicse results of introspection. They show that verbal imagery is impaired by injury to the visual, to the auditory, or to any tactualmotor centre, or by injury to the neurones connecting these areas, and that corresponding with these different pathological conditions there may be independent loss of words as read, as heard, as spoken, or as written.
Several general conclusions follow from the study of the sense-orders of our images: the impossibility, first of all, of supposing that any normal person is unimaginative. Since imagination is not of necessity an artistic impulse, a lofty soaring in empyrean isolation from the everyday life, but merely, as we have seen, the imaging of colors, sounds, pressures, odors, tastes, or even of words, it follows that everybody who is conscious of anything whatever, in its absence, is in so far imaginative. When I am conscious of the hat which I yesterday bought or of the dinner which I shall eat to-day, no less than when I muse upon the picture I shall paint or of the world I shall discover, I am, in a strict sense, imaginative. Our study, furthermore, makes it clear that almost everybody is capable of inciting himself to vivid and accurate imagination of one sort or another. If, try as he will, the colors are washed out and the outlines indistinct in his visual images of an opera or of a country outlook, he may hear, in imagination, the varying parts of strings and horns in the orchestral prelude, the melodies of the songs and the harmonies of the choruses, or the liquid bird-notes, lapping
waves, and murnuiring leaves of the summer afternoon. Even the minor image-types may be well developed, as the experiences of many defectives show. Helen Keller, who has been blind and deaf from earliest childhood, so that she can have neither visual nor auditory imagination, none the less imagines with peculiar vividness and detail pressures, movements, and even tastes and smells. A passage from her " Story of My Life " illustrates this lively and accurate imagining and may fitly close this chapter : —
"Everything," she says, "that could hum, or buzz, or sing had a part in my education — noisy-throated frogs, katydids, and crickets held in my hand till they trilled their reedy note. I felt the bursting cotton bolls and fingered their soft fibre and fuzzy seeds . . ., I felt the low soughing of the wind through the corn stalks, the silky rustling of the long leaves, and the indignant snort of my pony ... as we put the bit in his teeth. ... Ah, me! How well I remember the spicy, clovery smell of his breath."
IMAGINATION
In the second section of the preceding chapter, imagination — and, by implication, perception — have been described accorcHng to sensational content. But the sensational elements themselves have been only incidentally considered. To repair this neglect, it will be well to recur to our initial example — I am writing with a blue pen on a warm summer's day within sound of a gardener's whistling. My present consciousness includes, therefore, the experiences of blueness, of whiteness, of tone, of warmth, and of pressure. These sensational elements of my consciousness maybe studied in any order. In this chapter, the first to be considered are
Here we come at once upon a curious fact. An elemental consciousness of color, the experience of green, for example, is utterly indefinable. I'^.vcry normal person realizes, yet no one can tell, what it is. I may say, "I am conscious of green in looking at the trees;" or, "my consciousness of green is produced by a mixture of blue and yellow pigments;" but these are statements about the consciousness of green, not
descrii)tions of it. In truth, such descriptions arc inherently impossible because description, or definition, invohcs an analysis of content, whereas an elemental experience is irreducible, that is, further unanalyzablc.
It follows that very little may be said, in terms of mere description, about the sensational color-qualities, that is, the elemental kinds of color-consciousness. At least four sensational color-qualities (that is, kinds of color experience) arc admitted by almost all psychologists as unanalyzablc, or Red Yellow elemental. These four are the con-
sciousness of red, of yellow, of green, and of blue ; they are often described, also, as 'principal colors,' and for the following reason : If we have a succession of color-experiences in the spectrum order, we are certain to recognize
sciousness of yellow to consciousness of green, and so on; and that the experiences nearest to each end term differ from it by being like one or other of the contiguous end terms. For example, my consciousness of yellowish orange differs from that of yellow by being like both the consciousness of red and the consciousness of yellow ; whereas my consciousness of olive differs from that of yellow by being like both the consciousness of yellow and the consciousness of green. We rightly, therefore, distinguish between the elemental experiences of red, yellow, green, and blue, and the other color-experiences, each of which is like two of the elements or 'turning-points' of the color-square. Some psy-
Elemental Visual Experiences 31
chologists believe that only tlic four ' ])rinci])ar color-qualities are elemental and that all the others are analyzablc into two or more of the four. Other i>sychologists hold that there arc as many elemental as distinguishable color-experiences. Into the details of this rather academic discussion we need not enter.
Besides our experiences of color — of red, green, blue, and the like — we have also the introspectively different experiences of colorless light, that is, of white, gray, and black. There is wide diversity among psychologists in their account of the relation of these experiences. Some reckon the consciousness of gray as a complex experience analyzable into that of white and of black ; others hold that there is but one colorless light ciuality — the consciousness of gray, and that the exjjeriences of white and of black are really experiences of light and dark gray.* A third view enumerates among the colorless light elements the consciousness of white, of black, and of all distinguishable grays. A fourth view recognizes three colorless light qualities (the consciousness of white, of ])lack, and of gray), explaining the differences in sensations of gray as distinctions in intensity. It is unnecessary and perhai)s impossible to choose between these accounts. The important ])oint is to note the evident distinction between the 'colorless-light qualities,' the consciousness of white, of gray, and of black on the one hand, and the 'color-qualities' on the other. Significant also is the fact that though one may have the colorless-light consciousness without the color-conscious-
* For experiment, rf. Sanford, "Experimental Psychology," 140a. (References througliout the footnotes to "Sanford" are to this book; and the numerals refer to his numbered experiments.)
ncss — in other words, lhoiifj;h one may see white, gray, or black untinged by color — one is never conscious of color without colorless light. In the terms of physics : we never see an absolutely pure or, as it has been called, a 'saturated' blue or red. Most of our colors, indeed, are decidedly ' unsaturated,' that is to say, they seem to be mixed with colorless light.
of which resembles both the consciousness of color or hue and that of dark gray or black. An admirable way in which to represent to ourselves this wealth of our visual experience is by the figure known as the color j^yramid.* The base of
this symbol represents the exj^iericnces of most saturated color — those in whieh there is least consciousness of white, of gray, or of black. Its rectangular form suggests the fact lliat tlic consciousness of red, of yellow, of green, and of blue arc, as has been shown, turning-points in the colorquality series. The dotted vertical represents the ex])erienccs of white, of gray, of black. Toward the top, the surface of tlic pyramid represents the experiences of pale green, of straw-yellow, of sky-blue, and of pink ; toward the bottom the experiences of indigo-blue, of l)rown, of dark red, and of bottle-green, are represented. "All these tones," to quote Titchener again, "are the most saturated possible, the most coloured colours of their kind," l)ut " if we peel the figure" (like an onion), "leaving the black and white poles untouched, we get precisely what we had before, save that all the colour tones are less saturated, lie so much nearer to tlie neutral tones."
2. Visual Intensities: Experiences of Brightness
One cannot be conscious of a color, a red or a blue, for example, or of a colorless light, a white or black or gray, without being at the same time conscious of brightness. The experience of brightness as well as that of color or of gray, is a distinct and unanalyzaljlc element of consciousness. It cannot, of course, be separated from the consciousness of colorless light with which it is coml^ined, but it may be jierfectly distinguished from it. The visual intensities are, as every one admits, indefinite in number. They are furthermore distinguished from sensational qualities of color and of
colorless li<j;ht, by their capacity for direct and simple serial arrangement.* ^^ liut, ])artly because our practical and aesthetic interests are concerneil only with extremes of intensity, we are not interested in naming the experiences of brightness as wc arc in naming those of color. For these reasons, the visual intensity-elements are estimated by comparison with each other, and not with reference to absolute standards; and the intensity-series can be indicated only b}words : " bright — brighter — still more bright, etc."
3. Visual Elements of Exiensity
Always along with our consciousness of color we experience a certain bigness, or extensity.* ^^ This, too, is an elemental sensational consciousness, an unanalyzable experience quite distinct from every other. In the words of James, it is " an element in each sensation, just as intensity is. The latter every one will admit to be a distinguishable though not separable ingredient. ... In like manner extensity, being an entirely peculiar kind of feeling indescribable except in terms of itself, and inseparable in actual experience from some sensational quality which it must accompany, can itself receive no other name than that of sensational element.''^
have next to seek some exjjlanation of them. A brief reflection will con\ince us that this ex|)lanation cannot be in terms of psychology, for very evidently it does not depend on me whether my present experience includes consciousness of green- or of blue, of bright or of dull, ) The accepted explanation of every sort of sensational consciousness is in terms of ])hysics and physiology, and the explanation of the colorconsciousness is somewhat as follows : I have the sensational consciousness of green, let us say, because green light, namely, ether vibrations nearly six hundred billions to the second, are refracted by the lenses of my eye to the retina, and there excite a physiological process which is propagated by the optic nerve to the occipital lobe of my brain. Thus the physical condition of our consciousness of color is ether-vibrations. The ether is described by physicists as an ' incompressible medium' of extreme tenuity and elasticity which is supposed to pervade all space and to penetrate within the molecules of material substances. So impalpable a material has never been actually observed, but its existence is hypothetically assumed, because it offers the only plausible explanation of many physical phenomena. Because the ether pervades all bodies, it must be thrown into motion by their vibrating molecules, and its periodic, transverse vibrations are assumed to be the physical stimuli which condition the sensational qualities of color. Thus the colors vary according to the number of ether vibrations in a given time. The slowest vibrations, about four hundred and fifty billion each second, condition the retinal process which accompanies the sensational quality ' red ' ; and the swiftest vibrations, about seven hundred and eighty billion each second, form the physical stimulus to 'violet.' The following table includes these
figures for five colors, naming also the length of the cthcrwavcs, that is, the tlistance from wave to wave. It is evident that the longer the waves the smaller the numl)cr which can be propagated in a given time : —
The external conditions of the consciousness of colorless light are more complicated. Two sorts of relation between stimulus and consciousness must be distinguished ; the consciousness of white, gray, or black is due either (i) to a mixture of colored lights or (2) to a single colored light.
(i) Not every combination of colored lights produces the colorless-light consciousness, but for every colored light another may be found such that, if the two be mixed and if they fall simultaneously on the retina, a consciousness of colorless light will result. Color-stimuli which stand in this relation to each other are called complementary. Furthermore, a mixture of three, of four, and of more color-stimuli, rightly chosen, will produce the consciousness of colorless light; and daylight, which is yjhysically a compound of ether-waves of all wave-lengths, of course has the same effect.* (2) But
* For experiments, cf. Sanford, op.cit., 148c and 149a; Titchener, "Experimental Psychology, Student's Manual, (Qualitative," §8. (Footnote references to "Titchener" are toJhis book.)
the colorless-light consciousness results not only from mixture of colored liglUs; it is sometimes excited by a single stimulus. The three most important cases in which one colored light, falling on the retina, is seen as gray are (a) in the faint light or twilight when, as the saying is, "all cats are gray"; (b) in color-blind eyes ^^ to which some one color (most often red or green) or even all colors appear as gray ; * (c) when the colored light falls on the peripheral or outer edge of the retina. If, for instance, a small colored object be brought toward the field of vision from the right side, while the left eye is closed and the riglit eye firmly fixated on something directly in front of the face, it will be found that the colored object at first seems gray, and that it is seen in its true color only as it approaches the centre of the eye.f
of Color and Colorless Light
Even the attempt to offer a physical explanation of our visual sensations has led us, thus, to refer to physiological retinal conditions. We must now undertake a completer enumeration of these physiological conditions of vision. And it will be convenient to describe together the conditions of the colorconsciousness and the colorless-light consciousness.
In brief, the main physiological conditions of vision are the following: (i) A specific retinal process; (2) an excitation of the oi)tic nerve which connects retina and brain; (3) an excitation of the visual 1)rain centre — pr()ba1)ly the cortex of
t For experiments, cf. Sanford, 137 «; Titcluiur, §(>; C. E. Seashore, "Elementary Experiments in Psychology," Chajjter III. (Footnote references to "Seashore" arc to this book.)
the occii)ital lobe. Besides these antecedent, or conditioning, physiological j)rocesses, there occur always (4) accompanying and following nio\ements of e\es and head.
In considering the nature of the retinal process which excites color- vision, it is necessary to have in mind the structure of the human eye/'' Roughly speaking, it is a sort of sjjherical camera obscura, protected by a shutter, the eyelid, and containing a compound lens whose refractiveness (or ability to focus light-rays) changes, so that clear images now of near and now of far objects may be thrown upon its plate, the retina. More literally, the eyeball is a sphere, moved by six strong muscles, composed of three membranous layers enclosing certain transparent substances, and pierced, from the rear, by the optic nerve. The outside layer of the eyeball is an opaque, whitish membrane, the sclerotic, which in its forward part becomes transparent and is called the cornea. The forward portion of the second, or choroid, coating of the eyeball is the iris, which we see as the * blue ' or ' brown ' of the eye. It is a sort of ' automatic diaphragm ' with an opening, the pupil, which grows larger in faint light and smaller in bright light. Behind the iris is the crystalline lens, most important of the transparent substances of the eye.y By an automatic muscular contraction it becomes more refractive when near objects are fixated. The third coating, the retina," covers the posterior two-thirds of the inner surface of the eyeball. It is composed of several layers, and the ninth of these layers consists of minute structures, of two types, known as rods and cones. These are so arranged that there are many cones and few rods in the centre, and many rods on the outlying portions of the retina. The rays of light from an object are refracted by the lenses of the eye, pierce through
the inner layers of the retina, and exeite the rod and cone layer. The activity of rods and cones stimulates the optic nerve, and the optic nerve, in turn, transmits this excitation to the occipital lobes of the cerebral hemispheres.
The retinal processes which condition the color and the colorless-light consciousness are very probably the following : ^(i) Colored light — for example, red light (that is, ether waves four hundred and fifty billion to the second, six hundred and ninety millionths of a millimeter long) — partially decomposes a chemical substance on the cones of the retina. There arc four possible phases of the decomposition of this cone-substance, and corresponding to them are the sensational experiences of red, of yellow, of green, and of bluc.'^ (2) A mixture of colored lights totally decomposes this same conesubstance, and the consciousness of colorless light follows. (3) The consciousness of colorless light due to a single colorstimulus is excited by the decomposition of a similar, but less comj)lex, chemical substance found on the rods of the retina. Any light stimulus suffices to break up this substance, and it is decomposable not in separate stages but only all at once. The three cases, already named, in which colored light excites colorless-light consciousness are thus explained : (a) When, as in twilight, the colorless-light stimulus is very faint, it lacks the intensity necessary to excite the processes of the cone-substance, whereas the rod-substance is jiarticularly sensitive to faint light." (b) When a colored light falls on the outlying, or perij^heral, part of the retina, it excites only the rod-substance, since this i)art of the retina contains no cones. (V) In partial color-blindness the cones of the retina may be ^supposed to be only partly developed, and the cone-substance to be decomposable in only two of the normal four stages.
In total color-blindness (if due to retinal and not to brain conditions) it may be supi)osed either tliat the retina contains only rods, and not cones, or that the cone-substance is as undeveloped as that on the rods.^^
Brightness and Exlcnsity
By a little amplification this account of physical and physiological processes may be expanded so as to explain also the consciousness of brightness and of visual extensity. The visual qualities are conditioned by the length, and the corresponding number per second, of the ether waves; the visual intensities, that is, the brightnesses, are conditioned by the wave amplitudes; the visual extensities, or bignesses, are conditioned presumably by the diffusion of the waves in space. The physiological conditions of these elemental visual experiences are probably the following: The 'qualities' (experiences of color and of colorless lights) are conditioned by the mode of the retinal excitation (partial or total decomposition of a retinal substance) , whereas visual intensities are conditioned by the degree of excitation ; and visual extensities are conditioned by the number of nerve-elements excited.^**
It must be noted, in conclusion, that color sensations stand in more constant relation to physiological than to physical conditions. The phenomena of color contrast offer an admirable illustration.^" If one look fixedly for ten to twenty seconds at an illuminated green window and then look off at a neutral background, the background will appear not white or gray, but pinkish-purple; of, if the illuminated window is blue, the background will appear as yellow. That is.
if a brightly colored object has been fixated, gray light falling on the same part of the retina results in the complementary color sensation — a case of successive contrast.* Here the objective stimulus, colorless light, occasions a sensation not of gray but of a color. The explanation, in terms of the special case, is the following: the green light has exhausted, temporarily, a j)art of the photochemical substance in the retina, so that the process normally resulting in sensation of green does not follow. When, therefore, the retina is stimulated by colorless light (a comljination of ether-waves of all \ibration rates) , the green constituent of the white light is inetTectivc, and its remaining constituents excite the processes which condition the consciousness of purple.
Cases of simultaneous contrast also occur: that is, gray objects, seen on a colored background, appear to be of color complementary to the background. f
a. ENUMERATION
We have so far analyzed into its visual elements my j)crception of the moment. But I am a hearing as well as a seeing self: I am listening, it will be remembered, to "The Road to Mandalay" whistled to the accompaniment of a lawn-mower ; and my experience includes at least one tonal quality, my consciousness of a pitch, say C, and a second auditory experience, perha[)s elemental — my consciousness of a whirring noise. The consciousness of pitch is the character-
istic factor of my consciousness that a tone is high or low, that a voice is soprano or alto. The most notable character of the pitch-qualities (experiences of ])itch) is their capacity for arrangement in recurring series, the octaves. The number of these tonal qualities (of pitch) is variously stated. On the ground that the trained hearer can distinguish about eleven thousand different tones, most psychologists assume an equal number of pitch-qualities. But on the ground of the close resemblance between a tone and its octave it has been urged that there are only as many pitch-qualities as there are distinguishable elements in an octave.* ^^
Psychologists are not agreed about the nature of our consciousness of noise. Many teach that it is a mere conglomerate of many pitch-qualities ; and in favor of this view it may be urged that in most if not all noises — in the roar of the streets, and in the hum of insects — we detect what we call pitch. Other psychologists hold that a consciousness of noise, even when complex, includes some characteristic noisequality — as, for example, the consciousness of puff, of thud, or of rumble. t These alleged noise-qualities have been distinguished as continuous or momentary, but have been, on the whole, insufficiently studied. On the other hand, experiences of pitch have been the object of minute consideration as forming an important factor of the aesthetic consciousness.
The elemental consciousness of a sound-quality, a pitch or a noise, is always fused, or combined, with the elemental experience of an auditory intensity, or loudness: that is, one is conscious of every sound as more or less loud or soft.
And according to many (though not to all) j)sychologists, the consciousness of quality and of intensity are fused also with that of auditory extcnsity, or bigness.^" This auditory extensity, or voluminousness, is the {)redominant factor in our distinction of one instrument from another — 'cello from organ, or llute from violin — when both are playing at the same pitch and intensity.
To sum up the results of the preceding paragraphs: the following auditory, sensational elements of consciousness occur: (i) auditory qualities (pitches, or tonal qualities and, perhaps, noise-qualities) ; (2) loudnesses, or auditory intensities; (3) auditory extensities. A fusion of loudness and voluminousness with predominating pitch-quality is a tone. A fusion of loudness and voluminousness with noise-quality is a noise. (Or, if the occurrence of specific noise-qualities is denied, a noise may be defined as a complex of tones without any one prolonged or emphasized pitch-quality.)
I. TJie Physical Conditions of Auditory Sensation
We shall find it convenient to consider the physical, and therefore secondary and remote, conditions of pitch and noise-quality, before regarding the more immediate physiological antecedents. The physical condition of the auditory consciousness in general may be described as oscillation of airparticles, producing rarefactions and condensations of the air. A rarefaction followed bv a condensation is called an
atmospheric wave, {a) The consciousness of pitch is, in all probability, occasioned by a succession of simple and regular atmospheric waves. The experience of noise is probably due either to a momentary unperiodic vibration, or to a combination of air- waves of nearly identical length — for example, to the complex of air-waves which are set into vibration when one simultaneously strikes a great number of piano keys. Different qualities of pitch are found by experiment to correspond to the varying length of the atmospheric waves. The swifter the atmospheric vibrations, that is, the greater the number and the shorter the length of the air-waves in any secondof time, the higher is the pitch-quality; and, on the other hand, the slower the vibrations, that is, the fewer and longer the air-waves in a second, the lower or deeper is the pitchquality. This is the principle on which all stringed instruments are constructed. The shorter strings of the piano are struck to produce its higher notes ; and the violinist's finger divides his string to obtain from the swifter air- vibrations, propagated by the motion of each half, a tone an octave higher than that produced by the slower vibration of the entire length. As, therefore, a definite number of ether-vibrations corresponds with each experience of color, so each consciousness of pitch has its air- vibration number : the consciousness of low c, for example (in what is called the small octave) , is produced, through the excitation of nerve-endings and brain-cells, by one hundred and twenty-eight vibrations; and that of its octave, c', is excited by exactly twice as many, or two hundred and fifty-six vibrations, ih) The amplitude of an atmospheric wave, that is, the length of the extreme excursion (one way or other) of each air-particle is the condition of our consciousness of sound-intensity; and the wave diffusion (the
Air-waves pass from the outer ear/** through a short tube, and strike upon a stretched membrane (the tympanic membrane) at the entrance to the middle ear. This membrane is thus thrown into \ibration and transmits its motion to a series of three small bones, which serve to transform amplitude into strength of vibration. The foot of the ' stirrup,' or inmost of these bones, fits into an opening in the inner ear ; and the inner ear is a complex of bony tubes, lined with membrane and filled with liquid, embedded in the temjjoral bone of the skull. Probal)ly only one of the three main divisions, namely, th& cochlea, oi the inner car has to do with sensational elements of sound. The cochlea contains a structure, the basilar membrane,*" made up of fibres graded in length so as to correspond to vibrations of different periods; and the auditory nerve has its ending in certain cells supported by these fibres.
The process whicli conditions hearing is, according to the theory of Helmholtz, the following : ^' The tympanic membrane, set in motion by an air-wave, say of one hundred and twenty-eight vibrations per second, communicates this motion to the bones of the middle ear and thence to the liquid contained in the inner ear. The movement of this liquid excites those only of the fibres of the basilar membrane whose vibration number is exactly, or approxi-
matcly, one hundred and twenty-eight. If several Ijaslhir membrane fibres are exeited by a (•()m])()und vibration, the complex consciousness of a clang, or chord, follows. The consciousness of noise is perhaps best explained as due to the excitation of basilar membrane fibres in which " one fibre does not vibrate more strongly than the rest." * This explanation covers not only cases in which the consciousness of noise is excited because " a considerable part of the basilar membrane is thrown into uniform vibration" by a complex of air-waves of closely similar vibration-number, but also those in which the consciousness of noise is due to an unperiodic stimulus which "lasts for an exceedingly brief time." For, in both cases, there is "no well-defined point of maximal stimulation,"
It should be added that the air vibrations which produce very high and very loud sounds may be directly carried to the cochlea by the bony walls of the skull. Very high and very loud sounds are therefore audible to persons who have lost the organs of the middle ear. But however the cochlear process is stimulated, and whatever is its nature, it excites the auditory nerve terminals in the basilar membrane cells, and the excitation is conveyed to the auditory centres in the exterior temporal lobes of the brain.'' As in the case of visual stimulation, such excitation always passes over into outgoing motor nerves, and bodily movements, especially head movements, result. Characteristic among these movements, in the case of the higher vertebrate animals, are adjustments of the outer ear such as w^e know so well in the dog and in the horse. Most human beings have lost the capacity for ear movements.
W'liile listcnint^ to the mower's whistling T am, it will be remembered, faintly conscious of the odor of freshly cut grass : that is, my sensational experience includes smelling as well as seeing and hearing. In i)urcly descriptive technical terms, there seems little to be said about the elements of smell-ex])ericnce. I can in truth discriminate many odors, which means that my smelling includes different sensational equalities and intensities; but nobody has succeeded in analyzing the experience into irreducible elemental qualities, fixed by definite names.'** Complex smell-expcricnces are named, ordinarily, from objects to which they belong; or are known simjjly by the feeling which accompanies them, as ])leasant or unpleasant.
Little is known of the external conditions of smell. The smell stimulus must be gaseous in form, and it affects endorgans lying in the membranous lining of the upper part of the nostrils."*. The nostrils open into the pharynx ; and thus the smell end-organs may be excited by way of the mouth cavity, and it is also true that particles may reach the mouth through the nostrils. The following section will call attention to one result of this close connection Ijetween smell and taste-organs. The cerebral centre for smell is in the median side of the tem))oral lol^es," and the excitation of this brain centre is normally followed by characteristic movements.
The ordinary in(H\idual, asked to name what he had 'tasted' at dinner, might answer that he had tasted beefbouillon, roast duck, potato, onion, dressed celery, peach ice, and colTee. But the psychologist would conclude at once that some of these experiences were complex, made up of simpler elements. And the ex])erimentalist would go farther: he would take means to isolate, so far as he could, the conditions of taste, so that other sense-elements should be shut out from consciousness. To this end he would select, if possible, as subject of the experiments, an anosmic person, that is, one without smell-sensations, or else he would close the subject's nostrils, so as to eliminate most of these smell-sensations; and he would certainly blindfold the subject, to prevent his seeing the articles which he tasted. These substances would be presented to him at an even temperature, and the solids would be finely minced so as to be indistinguishable in form. Judging by the results of actual experiments, in particular those of Professor G. T. W. Patrick, the results of such a test, as applied to our suggested menu, would be the following: the blindfolded and anosmic subject would as likely as not suppose that he had tasted chicken broth, beef, potato, an unknown sweetish substance, another unknown material mixed with a thick, tasteless oil, a sweet unflavored substance and a slightly bitter liquid — perhaps a dilute solution of quinine. A normal person, also blindfolded, but without closed nostrils, would recognize the onion, the peach, the coffee, and often the olive oil; but would be likely to confuse the beef and the duck; whereas, if these were unsalted, the anosmic subject would fail to recognize them
even as meats. Certain substances, on the other hand, for instance, the different sorts of bread, of white, graham, and rye flours, would be better (hscriminated by the anosmic subject.
These results are easy of interpretation. What we know as tasting is a complex experience 'made up' of experiences of odor, of pressure, and of pain — not to speak of visual elements — in varying combination with a limited number of distinct exj)eriences of taste, (i) The consciousness of odor is the significant factor in 'tasting' egg, fruit, wine, onion, chocolate, coffee, and tea. Tea and coffee are, indeed, undistinguished from quinine, when the odor-elements are excluded, and are differentiated from each other only by the slight astringency of the tea, that is, by the peculiar pressure-experience, the 'puckering,' which it incites. (2) The experience due to tasting nuts, vegetables, or grains forms a second class, for it consists, in large j^art, of pressure-sensations excited by stimulation of the tongue. It follows that because of his trained attention to degrees of roughness, smoothness, hardness, and softness, the anosmic jK-rson can distinguish better than the normal person, if both are blindfolded, breads made of different grains. (3) The ex])erience of pungent taste, in the third place, is largely distinguished by sensational elements of pain and ])erhaps of heat. (4) And finally, in another kind of tasting, the important feature is visual, as is j^roved by the fact that the varieties of meats and of bread are so frequently undistinguished by tlie blindfolded oljserver.
But, though so-called tasting is thus proved to contain the sense-consciousness of smell, of ])rcssure, and of color, it is characterized also by certain distinctive elemental taste-
experiences. According to experimental introspection, there arc four lastc-(iualilics: sweet, salt, sour, and bitter, besides an indefinite number of sense-intensities. Some psychologists believe there are also taste-extcnsities, that in eating roast beef, for example, one has a consciousness of bigness, absent from the consciousness of lemon. It should be noted that the taste-qualities, the experiences of salt, sweet, sour, and bitter, do not introspectively order themselves either (like the color-qualities) in an articulated series, or (like the auditory qualities) in a periodic series. Like the colorqualities, however, they are capable of contrast effects — for example, lemonade is very sour after ice-cream.*
Concerning the external stimulus of taste, little can be said. Chemically distinct substances may even arouse the same sensational quality; for example, both sugar and acetate of lead give a ' sweet' taste. The stimulus must, however, be in liquid form ; for, if the top of the tongue be carefully dried, a grain of sugar or of quinine placed upon it will not be tasted till the tongue becomes moist again. The physiological endorgans of taste are minute structures contained in the mucous membrane of mouth and of throat, especially in the papillae (or little hillocks) of the tongue.^^ The cerebral centres are probably near the smell-centres,^ and the characteristic motor accompaniments are movements of the tongue.
new-mown hay, but I am conscious of grasping my i)cn. My sensational consciousness certainly includes the experience of tactual quality, of tactual intensity, and of tactual bigness. Everybody admits that there are indefmitcly many pressure intensities and extensities, and it has been thought that as there are many qualities of color and of pitch, so also there are many pressure-qualities — the experiences, for example, of contact, of hardness and softness, of roughness and smoothness, and of wetness. On close inspection these turn out, however, to be complex (though relatively simple) experiences in which pressure-quality is the essential component. Thus, the consciousness of contact is that of faint pressure ; the experience of smoothness seems to be that of uninterrupted pressure; and the alleged sensation of hardness is a complex whose chief constituent is the sensation of intense pressure due to excitation of end-organs in the joints. The experience of wetness seems, at first thought, unambiguously elemental and unanalyzable, but it is really a complex of warmth or cold consciousness combined with the experience of smoothness and, often, with a visual image of the licjuid stimulus. This is proved by the fact that one often cannot tell the difference between dry or wet hotness or coldness. One does not know, for example, by the mere 'feeling' of them, whether one's feet are w^et or merely cold ; and whether a hot compress is dry or wet.
The physical stimulus of our pressure-sensations is mechanical. As it atTects the skin, it must produce an actual deformation ; and we therefore feel the surface pressure of a large object only at its terminal lines: for example, if the hand is plunged in water, the pressure is felt only where the wrist emerges. But contact with the skin docs not alwavs result
in pressure-sensation. For, contrary to our usual view, the skin is not, as a whole, sensitive to pressure stimuli.-" If I am blindfolded, and a small blunted point of cork or wood is drawn gently over the surface of any part of my body, for example, of my arm, I shall feel it as touching my skin at certain points only — usually at the roots of the hairs of the skin, but in hairless spots also.* This shows that certain minute structures embedded in the skin are end-organs of pressure; and it has been found that these organs are of two sorts: (i) hair-cells and (2) more developed structures known as Meissner's corpuscles.^^
NAL EXCITATION
End-organs of pressure are found not only in the skin but on the joint-surfaces, and perhaps embedded in the muscles.^^ Pressure-sensations through bending the joints are, indeed, strong and readily discriminated. One may readily convince oneself of their occurrence if one lower a weight by a string attached to the forefinger till it strikes floor or table. At the moment when it strikes, one experiences a sensation, evidently of pressure, which can only be due to the backward movement of the lower upon the upper joint-surface of the arm.f
Besides these admitted pressure-sensations, there are several other sensational experiences due also to internal excitation, of which, probably, or possibly, pressure-sensations are the main constituent. These internally excited sensations are (i) the alleged sensation of strain. This is occasioned by
lifting weights and by assuming rigid bodily attitudes. A simple way to excite it, for example, is to clench the hand firmly, but in such wise that its surfaces do not touch each other. No external [pressure can then be felt, but the resulting experience is said to include, not only a weak sensation of pressure from the moving of the surfaces of the finger- joints on each other, but also a new experience, that of strain, regarded by some as elemental, by others as a complex consciousness of pressure and of pain. It is specifically due to excitation of the tendons.
(2) A second alleged sensation from internal excitation is that of dizziness, due to excitation of the semicircular canals.*^ What is known as dizziness is probably either a complex experience or a mere pressure-sensation. It includes, or is closely accompanied by, moving visual images of objects and figures rotating slowly, or slipping and swimming about in one's field of vision. It is furthermore sometimes, though by no means invariably, accompanied by the feeling of nausea. For the rest, it seems to consist of a pressuresensation 'located' within the head.
(3) So-called 'organic ' sensations are more evidently complex ex])eriences. These include (a) the so-called sensations from excitation of the alimentary canal, hunger, thirst, nausea, and (b) the so-called circulatory and respiratory sensations. Carefully analyzed, each of these, in the writer's opinion, will disclose itself as complex, and not, in any sense, elemental. Thirst, for example, is a complex of pressure and warmth sensations; it is due to a drying of the mucous membrane of the mouth-cavity, which becomes a ])oorer conductor of warmth. The chief element in hunger, also, is probably that of pressure, brought about by some chemical
action on the lining of the stomach. What is called nausea is a still more complex experience, but its essential ingredient is pressure, due to the antiperistaltic reflexes of the oesophagus.
The alleged respiratory sensations, such as breathlessness, suffocation, and stuffiness, are evidently experiences including several elements: first, and most important, pressure-sensations; often also, sensations of strain, as when one holds one's breath; and, finally, for most people, a visual image of the part of the body — chest or throat — which is affected. The 'circulatory' sensations are either, like itching and feverishness, compounds of warmth and pressure-sensations, or else they arc the massive pressure-sensations from difficult breathing or from abnormally strong heart-beat.
These 'organic' experiences, though seldom attended to, are nevertheless of great significance, for they may form part of our most complex ideas and moods. Emotions are, as we shall see, especially rich in 'organic' sensations. When, for example, I am afraid, my heart flutters ; when I am grieved, my throat is choked ; when I am perplexed, there is a weight on my chest. And though I concern myself little with these seemingly unimportant experiences, they none the less effectively color my moods.*
The cerebral condition of pressure-sensation, whether from external or from internal excitation, is, in the view of most physiologists, excitation of the region about the fissure of Rolando.'' From this centre, motor nerves spread outward and downward to all muscles of the body (and limbs) and pressure-sensations are, therefore, normally accompanied and followed by bodily movements of all varieties.
VI. Elemental Pain Experience
The pin point which, gently applied, excites first a sensational experience of pressure, may bring about, an instant later, a very ditTerent sort of consciousness, that of pain. This is evidently distinct from all other sensation-elements through stimulation of the skin, and no good observer confuses the pressure-consciousness with the pain due to a heavy weight. But it is perhaps less easy to realize that the consciousness of pain is quite distinct from that of unpleasantness. It is unpleasant, for example, not painful, to discover that one has given to the deck steward twice too large a fee; and the sight of the rose-pink gown of the lady with auburn hair is unpleasant and not painful. The confusion is mainly due to the fact that the sensational ex|)erience of ])ain is always accompanied by unpleasantness. In the case of apparent exceptions, as of the slight pain which we intentionally inflict upon ourselves to see how it will feel, the pleasantness is probably that of the novelty, not of the pain. But it does not follow from the fact that j^ains are always unpleasant, that unpleasantnesses are always painful, still less that the two are identical. Our first conclusion, therefore, is that painfulness, an experience which follows upon the burning, bruising, or cutting of the skin and ujx)n certain internal changes, is dilTerent from unpleasantness or disagreeableness.
Some psychologists believe that there is one quality of pain, as of pressure, and that the experiences which we differentiate as acute, dull, stinging, gnawing j)ains are qualitatively the same, though differing in intensity, i)erhaps in extcnsitv or bigness, and in steadiness. Professor Ebbinghaus, on the other hand, teaches that there arc two pain-([ualities, the
When we ask for the physical condition of pain we are met by an unusual relation. For every other form of sense-quality we have found a dcfmite, even if vaguely characterized, physical stimulation. In the case of pain, however*, it is obvious at once that no specific form of energy occasions it, but that the same stimuli which excite sensations of pressure, warmth, and cold, and possibly even those which excite visual and auditory sensations, may bring about painfulness also, if only they are very intense, long-continued, or often repeated. Hard or long-continued pressure, intense heat and cold, and possibly blinding lights and crashing sounds may be called painful; whereas excessive sweetness and heavy fragrance are merely unpleasant.
It used to be held that just as, physically, pain seems due to high degrees of mechanical and thermal stimulus, so, physiologically, it must be referred to excessive functioning of pressure (perhaps, also, of warmth and cold) end-organs. But this is disproved by the fact that certain anaesthetics destroy the sensitiveness of the skin to pain stimuli, whereas other drugs make the skin insensitive to pressure. If the oculist treats one's eye with cocaine, one is distinctly conscious of the contact of his instruments, but feels no pain ; a similar use of saponin annihilates pressure-sensations and leaves pain. Furthermore, 'pain-spots' have been found on various areas of the skin f — whereas, from other parts, large areas of the cheeks, for example, they are lacking. When these spots are excited by any stimulus, mechanical or thermal,
Elemental Experiences of Temperature 57
electrical or chemical, consciousness of jmin without pressure results. Either, then, the skin must contain special end-organs of pain " — as most physiologists now hold — or, as Goldschcidcr the discoverer of pain-spots suggests, pain is physiologically due not to the activity of any nerve end-organs in the skin but to a transformation, in the gray substance of the spinal cord, of nerve-excitations conveyed from especially exposed pressureorgans.
Pain-sensation, like [pressure-sensation, may be excited within the body; yet the abdominal organs are, in the main, insensitive to mechanical and thermal stimulation, " may be handled, pinched, or cauterized," as Foster says, "without pain or indeed any sensation being felt." The consciousness of pain is, however, conditioned by excitation of the external i)eritoneum and the lining of the abdomen, and by pressure against the diaphragm. No special cerebral centre of pain is known. jSIovements of avoidance and withdrawal accompany the experience.
Experiences of warmth, cold, and hotness are grouped together because of apparent similarity. Nobody questions that the consciousness of warmth and that of cold are elemental experiences, further unanalyzable and radically different from other sorts of sensational consciousness — from the consciousness of pain or of pressure, for example. It is less easy to classify, introspectively, the sensational experience of hotness. Clearly, it is not, as is often assumed, merely an intenser consciousness of warmth. But whether it is a third elemental experience or a complex of warmth and
No direct relation can be discovered between the degree of the thermometer and the cold, or warmth, or heat sensation. In other words, we are not always warm when the thermometer registers a high degree, and cold when it stands at a low figure. On the contrary, the room which seems warm to me as I enter it after a brisk walk seems chilly an hour later, though the height of the mercury is unchanged; and if I warm one hand and cool another, the same lukewarm water will seem cool to the first and warm to the second.* These experiences, and others like them, seem clearly to show that the surface sensation of warmth or of cold or of heat is not determined by the actual temperature of an organ, but by the relation between the temperature of an organ and that of its environment. When the physical temperature of the organ exceeds that of its environment, the sensation is of cold; and, on the other hand, when the temperature falls below that of the environment, one has the experience of warmth, changing — as we have seen — at a certain point to that of heat.
The thermal stimulation of the skin is occasioned in two ways: by radiation of heat from outer objects and by muscular activity, which means loss of energy in the form of heat. I may grow warm, for example, by basking in the sun, or by swinging dumb-bells. Not the skin as a whole, however, but certain definite end-organs are affected. This is shown by applying warm and cold surfaces of very small extent to different parts of the body. A bit of metal may
be moved along for some little distance on the surface of the body, without rousing the experience of cold, which, however, will suddenly occur as the stimulus reaches one of the 'cold spots' over an end-organ of cold. There are fewer of these than of pressure or pain spots, and the warmth-spots are least frequent of all and most scattered.* The cornea of the eye is sensitive to cold, but not to pressure; and both warmth and cold spots are found within the mouth-cavity where no pain-spots have been discovered. Most of the inner surfaces of the body, however, seem to lack warmth and cold end-organs. Even the mucous lining of the mouth-cavity is less sensitive than the outer skin, so that one may drink, with perfect comfort, coffee which seems unbearably hot if it touches the lip."
The sj)ccific end-organs of warmth and of cold have not been definitely determined. But experiment seems to show quite conclusively that I feel hotncss when end-organs for cold and for warmth are simultaneously excited. No special cerebral centre is known, and no peculiarly characteristic movements follow.
With this consideration of our sensational consciousness of warmth and of cold we have come to the end of our merely structural analysis f of percejition and imagination into sensational elements. Two ])oints must be touched upon, in conclusion. It must be noted in the first place that a sensational quality always occurs in close combination with an intensity and often with an extensity. One is, for example, simultaneously conscious of bigness, brightness, and blueness as one looks at the summer sky. The fusion of quality
with intensity (and with bi^t^ncss) is called sensation. Some psychologists treat the sensation as unit of perception and describe the qualities, — of color, pitch, and the like, — the intensities — brightnesses, loudnesses, and so on — and the extensities, not as sensational elements but as attributes of sensation.'-"
The succeeding chapter will speak further of fusions. In the meantime, a word must be said of the physiological conditions of perception and imagination. In ordinary perception, some sensational elements are excited through stimulation of end-organs (that is, 'peripherally' excited), whereas all sensational elements in imagination are conditioned by brain excitation ('centrally' excited). So, when I imagine the Theatre of Dionysos, at Athens, only my occipital lobe is excited, but when I look out at Symphony Hall, my retina is excited as well; when I imagine the flute-like song of the hermit thrush, only my temporal lobe is excited; but when I hear the telephone bell ring, the inner organs of my cochlea are in vibration.
It should be noted that this account of the physiological condition of perception does not hold in the case of the hallucination. The hallucination, like the illusion, is a perception which does not directly correspond with any external object.* Both hallucination and illusion are perception — that is, involuntary and predominantly sensational experience, reflectively attributed to other people, of objects regarded as impersonal and external. But whereas the illusion includes peripherally excited elements, a hallucination contains only centrally excited sense-elements. The dream or delirium
FJcmcnial Rxpcrinucs of Tcui pcratuyc 6r
imac;c of a ghost, for example, is a hallucination, because it is not excited l)y any external object, whereas the traditional confusion of window-curtain with ghost is an illusion. Evidently, therefore, the hallucination, though a form of j)ercej)tion, is not distinguishable, by [)hysiological condition, from imagination.
'I'here is jierhaps a danger lest this long, though at every point abbreviated, study of ourselves as sensationally conscious may retard our ap])rehension of the essential nature of our ])erceiving and imagining. We run the risk of not seeing the woods for the trees — of missing the figure for the details. For this reason, we shall here again summarize the basal conclusions of the two preceding chapters without special reference to the structural analysis undertaken in this cha])ter. According to these conclusions, perception, like imagination, is the comj)lex and predominantly sensational consciousness of a particularized impersonal object in relation to myself. But the perceiving self differs from the imagining self (i) in that it knows itself to be involuntarily conscious; (2) in that it may later regard itself as having shared its experience with unj)articularized other selves; and (3) in that it regards its imj^ersonal object as external, that is, indei)endent of itself. The imagining self, on the other hand, to some degree controls its ex|)erience, which, accordingly, is regarded as more '])ri\-ate' and as normally unshared ; and its objects are not externalized. To recur to our initial exam{)le: I am sensationally conscious both of the desk which I see and of the Tyrolese landscape which 1 imagine; but I realize that I am inevitably conscious of an external desk, whereas I mav direct mv attention awa\' from mv mountain-
image; and (as I later relleet), I share my conseiousness of the desk with the housemaid who dusts it, whereas she does not know that 1 am imagining snowy mountains any more than I know what enthralHng image brings the smile to her lips and diverts her attention from the dustiest corner of the desk.
lation
It has appeared, in an earlier chapter, that perception and imagination are analyzable into irreducible sensational elements. It is necessary now to emphasize the fact that in ordinary ])erceiving and imagining one is not aware of these elemental constituents of consciousness, the different qualities, intensities, and extensities. Such analysis is the reflective work of the psychologist, not the immediate experience of the perceiving self. Thus, one's immediate consciousness of a tone is an undistinguished, unitary consciousness, and is not an awareness of a pitch, an intensity and a timbre, though tone-consciousness is analyzable, in after reflection, into these factors, and though it is due to cHstinguishable physical and physiological conditions. Similarly, the immediate consciousness of a tone sounded simultaneously with its octave is rarely an experience of two tones as distinguishable from each other, though united; indeed, it is often difllcult to differentiate these tones even by an effort of attention.
By fusion is meant, therefore, the absence of discrimination in an experience which is nevertheless (i) due to several endorgan excitations, and therefore (2) analyzable in after-reflection into distinguishable elements. The combination, for example, of the C and G, the loudness, and the volume of a given chord, is a case of fusion; and so is the combination of the experiences of redness, yellowness, colorless light, brightness, bigness, odor, coolness, pressure through joint and skin stimulation, and of pleasure, from an apple which one is rolling about in one's hand. Each one of the combined or fused elements must be directly excited by the stimulation of an end-organ, and not merely indirectly excited through the stimulation, by connecting fibres, of the corresponding braincentres.
Fusions differ from each other only in the degree of closeness with which the diverse elements are connected, and this is tested by the difficulty of the analysis in different cases. The closest fusions which we know are those of the different elements invariably connected in a sensation, the quality, intensity, and extensity.* Almost, if not quite, as close as this fusion is that of a color with colorless light: this is the closest combination which we know of different qualities. Other examples are the fusion of taste and smell in many socalled tastes, of the experiences of pressure and of temperature in what is named touch, and of the consciousness of extensity and pressure in the experience of smoothness or of roughness.
Assimilation is the negative unity, that is, absence of discrimination, in an experience reflectively analyzable into simpler experiences of which one (at least) is a recurring
Fusion and Assimilation 65
consciousness, ccrcbrally excited. As T look, for example, at a j)olislied marljle. or at a velvet cloak, I get (besides the experiences of color and form, light and shade) a distinct impression of its texture, even though I do not touch it. Such a texture-feeling is, of course, cerebrally excited (for the endorgans in my fingers are not stimulated), and T explain it as due to my past simultaneous exi)erience of similar light-effects with feeling of roughness or of smoothness. Every adult perception is an assimilation as well as a fusion of simpler experiences. I perceive the automobile, — that is, 1 am conscious of its color, form, and motion, — though the only experience peripherally excited is the auditory consciousness of puffing and ringing. And I perceive the orange which the child in the street-car seat behind me is eating, — I am conscious of its color, and roundness, and rough, cool 'feel,' — though only my olfactory end-organs are excited. The reason in both cases is that J have often before received simultaneously the different sorts of impression. It follows, of course, that e\ery perception is the result not only of present stimulation but of past experience: that a man ])erceives more than a child, and a child than a savage. The baby, for example, burns his hand because his visual perception of fiame does not include the assimilated consciousness of heat; and the West Indian negro carries the wheelbarrow on his head because his perception of it does not include the assimilated consciousness of its being wheeled.*
* The term 'assimilation' is used, in this section, as equivalent to 'simultaneous association.' For the distinction often made between these expressions, see Appendix, Section VII. (§ i). For discussion of Successive Association, see Chapter VII.
nation AND Differentiation
Perception, like imagination, is sensational consciousness, and is, thus, a unity in the negative sense that the perceiver fails to differentiate elements of consciousness which are distinguishable to after-reflection. But both perception and imagination include also a certain consciousness, very often \ ague and unemphasized, of the connectedness, the harmony, the ' together-ness ' (to borrow a term from Dickens), and at the same time of the distinctness, of sense-elements. These experiences of unity and of distinctness may be called forms of elemental relational consciousness. They are more prominent in recognition, in thought, and in will than in perception and imagination; and the detailed discussion of them will consequently be postponed to later chapters.* Yet the consciousness of combination, or together-ness, and of distinctness, or apartness, form a part of certain experiences so predominantly sensational that they are best treated as forms of perception and imagination. Three such experiences form the topic of this chapter, but only one of these, the consciousness of space, will be considered in any detail.
a. The Elements of the Space Consciousness
My consciousness of space is analyzable into elements of three sorts : first and foremost, the sensational consciousness, visual or tactual, of mere extensity or bigness; second, certain relational experiences of distinctness and unification; third, the sensational experiences, mainly tactual, due to move-
The Consciousness of Space 67
ment of my limbs, or eyes, or body. The elementary consciousness of extensily or bigness is fused with our \isual consciousness of color and colorless light and with our tactual consciousness of pressure. That is to say, we are conscious both of colors and of ])ressurcs as extended." The consciousness of this blue or of this heavy object as more or less extended is, however, an indefmitely less complex experience than that which we call the consciousness of space. Such a consciousness of 'mere cxtensity' — a constituent, we may suppose, of the experience of the new-born child when his retina or hand is stimulated — is not a consciousness of precise size, of defmite form, or of exact position ; it is not even a consciousness of surface or of depth ; it is a vague, unrelated, elemental consciousness, to be compared, perhaps, with such spatial consciousness as a grown person has when opening his eyes in a dark room. Yet the elemental consciousness of extensity is the centre and core of the complex experiences of spatial form and position.
h. The Consciousness of Distance, or Apartness
The simplest form of my complex spatial consciousness is the experience, visual and tactual, of apartness or distance.' I sec, for example, that my ink-bottle stands apart from my paper-weight; and 1 am conscious, with closed eyes, that the collar and the cuff which chafe me are apart from each other. Some psychologists ha\'e regarded the experience of ajiartness as an elemental consciousness incapable of further analysis, but careful intros])ecti()n will disclose that it is made up of a consciousness of the two-ness, or duality (of sense objects or qualities) fused with a consciousness of intervening extensity. Thus, when I perceive that a red dot lies ai:)art from
a blue (lot, 1 am simultaneously conscious (i) of the redness and the jjlueness, (2) of their ilistinctness, and (3) of a certain extensity (that of a portion of the sheet on which the dots are written) as (4) condition of the distinctness of the dots. I am conscious, in other words, of extensity intervening between two colors. And when, with eyes closed, I am conscious that a warm object lies, at some distance from a cold object, on my arm, I experience the cold and the warmth, the distinctness, or two-ness, of them, and, once more, an intervening extensity. The nature and conditions of this complex experience of apartness must be studied in somewhat more detail. To begin with the experience of twoness: light-stimuli falling about .004 to .006 millimetre apart on the retina are realized as two.* With cutaneous stimulation the case is different. Experiment has shown that the consciousness of two-ness does not follow on a twofold stimulation of closely contiguous spots on all parts of the skin. If two points be placed upon any surface of the skin, some distance may be found at which they will excite the consciousness, not of two pressures, but of a single one. This distance varies in different localities, and is smaller on the mobile organs: about one millimetre, for example, on the tongue, two millimetres on the finger-tips, and sixty-five millimetres on the middle of the back. The areas within which two points are felt as one are called ' sensory circles, ' and it is important to notice that they are relatively, not absolutely, defined. That is to say, the skin is not mapped off into definite portions, such that a point near the edge of one portion is felt as distinct from a very near point which, however, is over the border of the given 'sensory circle.' On the contrary, the distance between any two points felt as one
The condition of the consciousness of two-ness is evidently, therefore, double excitation of skin and retina (providing always that the stimulating objects be at suflhcient objective distance from each other) . The consciousness of an extensity as separating or intervening between these distinct stimuli cannot be so simply explained. It will be convenient to consider first the cutaneous and next the visual intervening extensity. (i) There is no objective, or physical, stimulus, of the experience of an extensity 'between' two pressures: two separated points touch my skin, and the intervening surface is not stimulated. Yet I am conscious of intervening extensity. The explanation is probably the following : When two points touch my skin, I not only perceive the pressure and the two-ness, but I imagine the extended pressure of an object stimulating the intervening extensity. This imagination of an intervening extensity is probably to be explained by the fact that the two pressure organs have most often been excited not by separate points, but by a single object exciting both at once.f On the j^hysiological side, the explanation probably is the following: Nerve excitation spreads from the place of excitation to contiguous nervetracts, especially to those which have been frequently excited together. Therefore, the cerebral excitation due to the stimulation of separated points of the skin tends to rouse the cerebral excitation corresponding to the frequent stimulation of the intervening area of the skin.
cxtensity appears more simple. The cxtensity whicli is realized as separating the red and the blue dots is that of the white cackground; and in retinal terms, end-organs or substances, between those stimulated by the red and blue I.glit are excited by white light. The problem, here, is to explain why — when the whole retina is stimulated by the white light from the paper background — just this particular part of the stimulating background should be realized as in especial relation to the red and the blue dots; in other words, why this particular part of the total consciousness of extended whiteness should be combined with the consciousness of distinct red and blue. Again the explanation may be given in terms of habitual experience. We are accustomed to the sight of objects with edges in accentuated color ; and we see the 'middle ground' of these objects as cxtensity intervening between the two borders. We therefore gain the habit of regarding that part of a background which lies between lines, or even between dots, rather than any other part of the background, as related to these lines or dots.
My spatial consciousness is more than a mere awareness of cxtensity and apartness. I am at this moment, for example, conscious not only that my letter-paper has bigness and lies apart from my penwiper, but also that the paper is oblong and the penwiper round; and I am furthermore conscious that the paper is flat and the ink-bottle cubical. I am conscious, in other words, of two-dimensional and of threedimensional form.
consciousness in thai it explicitly includes the experience of unification of points. ''I'he [)oint' is 'the apart'; the form is a unification of points. The consciousness of two-dimensional form is almost certainly due, in part, to the movements made by eyeballs or hand in outlining or tracing an object; and probably, also, includes a vague consciousness of these outlining movements. Such movements are instincti\ely j)erformed as one perceives an object.* When I am visually conscious of my paper as rectangular and then of my |)en wiper as round, my eyeballs make two series of movements, characteristically and markedly differing from each otlier. If with closed eyes I am tactually conscious of these objects, my finger makes (or starts to make) in the one case a broken movement, in the other a sweeping movement, as it follows their outlines. Such outlining movements, whether of eye or of hand, may be more or less completely executed. The baby, who is finding out that the plate is round, continues the outlining, exploring movement of his finger all about its circumference. The grown person may make merely the first part of the movement; or lie mav make a slight and unnoticed movement ; or, finally, he may have merely a tendency to movement, that is, an excitation of motor neurones, without any actual muscular contraction. But without doubt these movements (of eyeballs, hands, and tongue) play an important part in the develoj)ment of the space-consciousness. The unattcnded-to experience of such movements (whether performed, and thus percei\ed, or merely imagined) probably constitutes a part of my complex consciousness of two-dimensional, or surface,
forms. The experience of surface-form may, thus, be described as a fusion of (i) the sensational experiences of extensity and of sense quality due to excitation of end-organs by stimulating object ; (2) the relational experiences of distinctness and of unification; and (3) the experiences, also sensational, due to the instinctive movements of the eyeballs and hand.
overestimated ; and this overestimation seems to be due to an attraction of the eye, as it follows the horizontal line inward toward the oblique lines. An inattentive consciousness of these movements seems to be part of a consciousness of form.
The consciousness of three-dimensional or depth form has still to be discussed.** I am conscious not only of rectilinear and circular figures, but of cubical and spherical forms. Our present problem concerns the nature and the conditions
of this experience of depth. Some psychologists hold that it is an elementary experience, differing from the consciousness of surface-extensity somewhat as the consciousness of red difTers from that of green. The more usual and, in the view of -the writer, the truer opinion is the following: The consciousness of depth-form is not an elementary and unanalyzable experience; rather, it is a consciousness of two-dimensional form fused with a very complex but very vague consciousness of the bodily movements necessary for apprehension of the object. These movements are either movements of the body-as-a-whole, or (in the case of such three-dimensional objects as are within grasp) movements of arm and hand outward from the body. Thus, the consciousness of the three-dimensional form of a house includes a consciousness of my body moving toward it and around it; anrl the consciousness of the depth-form, the specifically cylindrical character, of a barrel probably includes a dim consciousness of the movements by which I explore its form, as outward from my body. The notable feature of the consciousness of solid or depth-form is thus not the occurrence or consciousness of bodily movements, — for this belongs also to the experience of surface-form, — but the realized character of these movements as either motions of the body-as-a-whole or as movements of one of the limbs from or toward Lhe rest of the body.
It is important to realize that thisconsciousness of the bodv, which is so inherent a part of the consciousness of depth, is not instinctive l)ut, rather, very gradually developed. T, grown-ujj ])erson, feel — let us say — the pressure of one hand which I lay upon the other. The Httle baby may make a I>recisely similar movement of liis liand and may gain a pre-
ciscly similar touch consciousness. But he has not yet consciousness of his hand or of his body; that is to say, he does not connect the visual consciousness (the 'look') with the tactual consciousness (the ' feel') of his hand at rest ; nor does he connect the tactual consciousness, due to excitation of joint and muscle, of his moving hand with the visual appearance of it. Indeed he does not realize the identity of hand at rest with moving hand ; and still less is he conscious of any connection between hand, foot, and head. Not till the baby becomes conscious of all these experiences as related, and as relatively permanent, or reproducible, has he a consciousness of his hand ; and in similar fashion he must gain the consciousness of other parts of the body, and of the body as a unified whole.
An important condition of the depth consciousness is the occurrence of right and left eye images differing slightly. The experience of closing first one eye, then the other, when looking directly at a solid object, will convince every one that the right 'sees' slightly more to the right of a given object, the left eye rather more to the left of the object. The facts of stereoscopy ^ prove that the simultaneous occurrence of such images is folio wxd by the depth consciousness; for in looking through a stereoscope with eyes unmoving and parallel, pictures drawn separately for right and for left eye fall upon the two retinas; and I see the pictured object as single and solid.* The occurrence of right and left images is not, however, an essential or invariable condition of the consciousness of tridimensional form, for experiment shows that, with one eye closed, T may perceive depth. In this case a muscular change in the accommodation, and thus in the
Localization 75
icfractivcncss, of the eve may eondition the depth experience; or some visual character, perhaps the distribution of shadow on the object, may suggest it.*
d. Localization : The Consciousness of Position
My spatial consciousness includes, finally, the consciousness of ])osition. 1 am conscious not only that the paper is oblong and the ink-bottle cubical; but also that the ink-bottle lies behind the paper and to the right of the letter-scale. I am conscious also that the date of my letter is written above the signature ; I am conscious that the palm of my hand is touched near the thumb by a heated object, and touched near the little finger by a cold object; finally, I am perhaps conscious that a piano is being played above me.
It is evident that cases of localization fall into two classes: of three-dimensional and two-dimensional localization, as wc name them. The experience of the horizon or of the stars or of the outgoing ship as far away from me, and the experience of the ink-bottle as behind the paper, or of the desk as beyond "the chair, are cases of three-dimensional localization. Experiences of the signature as below the date, or of the cold object as inward from the warm object, are instances of the consciousness of two-dimensional position. Localization of either sort differs from the consciousness of form, in that it emphasizes apartness rather than unification. Yet localization, the consciousness of position, is more than mere consciousness of apartness, for one is sometimes conscious of objects as apart without being conscious of their position. One is sometimes conscious, for example, of the spatial distinctness of two stimulated points of the skin without
being able to designate either one as above or below, right or left, of the other. In truth, the consciousness of position includes, besides the bare realization of apartness, a specific consciousness, emphasized or unemphasized, of the body or of parts of the body. Thus, 'up' means 'near the head, ' and conversely, ' down ' means ' near the feet.' * Right ' means 'toward the more readily moving hand.' 'Out' and 'in,' 'in front' and 'behind,' are terms used with reference to the bodv as a whole in its relation to the field of vision.
The difference between the two sorts of localization has been suggested in the last paragraph. Three-dimensional localization — the consciousness that the mountain is far away, that the sound is behind me — is a consciousness of the apartness of an object from my body, and includes the consciousness of a movement imagined, initiated, or completed, of my whole body (or of a limb 'outward' from my whole body). Thus, the consciousness that the sky is over me includes a vague consciousness of my body floating upward, and the consciousness that the cake plate is in front of me includes the movement, or tendency to movement, of my arm toward the cake plate. In its developed form, three-dimensional localization involves a consciousness of three-dimensional space, an image gradually built up by the imagined addition of distance to distance, in all directions, from my body. Two-dimensional localization, the consciousness, for example, that the red stripe of the plaid is above the blue one, is conditioned bymovement (complete or incomplete, imagined or perceived) of eye or of hand; but this movement is not an outward movement, and the consciousness of body-as-a-whole and of space-as-a-wholc is lacking.
ncss of objects as near or far from my body, as in front or l)ehin(l, to right or to left of me — is of great Ijiologieal significance. An animal able to react promptly and accurately to the sight, sound, or touch which reveals the jjresence of dangerous foe, of friend, or of mate is evidently favored in the struggle for existence. It follows that the localizing reactions, and the consciousness of them, must have been advanced by the extinction of poor localizers and by the preservation and propagation of good ones.
Visual localization is conditioned by muscular changes, chiefly of two kinds. When (within certain limits) an object is moved nearer or farther from the eyes, there is first a change in 'accommodation,' ^ that is, in the contraction of the ciliary muscle, such that the crystalline lens of the eye either bulges farther forward or is more flattened, thus becoming more or less refractive as the object is nearer or farther ; there is, second, a change in the convergence of the two eyes such that the angle of convergence is more or less acute according as the object is farther or nearer.® As I look, for example, from the sail on the horizon to the rosebush at my windowsill, my eyes converge.
Other conditions of the consciousness of visual distance are, first, the occurrence of dilTering retinal images,* and second, a number of so-called 'signs' of distance, notably: (i) the distribution of shadows, (2) the apparent interference of intervening objects, and (3) mistiness of the atmosphere. The significance of these factors may be shown in many ways. Thus, a mask, hollow side to the observer, if so placed that
no shadows arc cast inside it, will seldom look concave; the arch in the design here outlined seems to lie behind the pillar ; and, since far-away objects appear hazy, hills and trees and houses look farther away on a misty day, while the horizon line seems almost to strike one in the face on a very clear day. That is, indeed, a reason why painters love foggy clays and misty
that they at once excite, or suggest, it.
Auditory localization has next to be considered — the experience, for example, that a mosquito is buzzing behind me or that a street-car is approaching from the right. Such localization may be described as consciousness of the position of a sounding object as above or below, before or behind, to right or to left, of my body : it includes a vague consciousness of a more or less incomplete movement toward the sounding object. Recent experimental investigations have concerned themselves with the nature and the conditions of auditory localization. ^^ It has been experimentally established that sounds from the right are never confused with sounds from the left, that sounds from in front are constantly confused with sounds from behind, and yet that two sounds, close together, are best discriminated when given in front or behind.
These facts arc best explained by llu- liypothesis, experimentally tested, that the chief conch'tion of the consciousness of auditory position is the comparative intensity of sounds as stimulating the right and the left ears. A sound from the right stimulates the organs of the right ear strongly, those of the left ear fainlly; and it calls out a mo\'ement or tendency to moNcment of the head toward the right. On the contrary, a sound from exactly in front and a sound from behind stimulate right and left ears with equal intensity and are readily confused. Two sounds, fmally, given close together, in front or behind, are well discriminated because a change in the ratio of intensities, received by the two ears from sounds which readily reach both, is easily perceptible. The measurement of the mere distance or apartness of sounds from my body is mainly, as experiments have shown, an inference from the greater or less intensity of the sounds; though the consciousness of differences in timbre may contribute also to the distance consciousness.*
The main results of this chapter may well be summarized in a concluding paragraph: The significant elemental constituents of the space-consciousness have been found to be: first, the sensational consciousness of extensity; second, relational experiences primarily of distinctness and of unification; third, the tactual sensational experiences due to movements of the body. The successive stages of the spatial consciousness,^ it has appeared, are, first, the consciousness of mere aj)artness — a consciousness of extensity intervening between two colors or between two pressures; second, the consciousness of form, or unification of separated [joints; third, the consciousness of position either of objects apart * For experiments, cf. Seashore, Chapter V.
from the body or of objects apart from each other. The consciousness of one's body and, in particular, of bodily movements has been shown to be an important factor in the consciousness of position and of depth.
The discovery of the importance of movement as concHtion of the space-consciousness, with the reahzation that a consciousness of movement is part of many spatial experiences, has given rise to a mistaken analysis of the consciousness of space — a denial of the occurrence of any elemental consciousness of extensity. According to this view, the consciousness of color or of pressure as 'extended,' 'big,' or 'spread out' consists solely in a consciousness of bodily movements gained by experience of the colored or tactual objects. This 'empiricist' account of the spatial consciousness must, however, be rejected." In the first place, it contradicts introspection, to which the bigness, or spread-outness, of an object surely is as distinct and unanalyzable a character as its Ijlueness. The empiricist doctrine is in opposition, also, to the results of experiments on persons who have recovered, through operation, from total congenital blindness. Such persons are able to recognize at once a difference between round and square objects, seen and not touched. The empiricist theory — that the extensity consciousness consists in the consciousness of eye or of hand movements — is founded on a correct analysis of our consciousness of form and of position, and on the correct observation that we learn, by experience only, to estimate sizes and to measure our movements to the actual distances of objects. But the proof of the significance of movement and the consciousness of movement, in our complex and developed consciousness of space,
A second perceptual experience of combination with differentiation — a consciousness, as Ebbinghaus calls it, of 'unity in diversity' — is that of auditory harmony." This consciousness of the differentiated unity of tones must be dis tinguishcd carefully from tonal fusion. When one vibrating body, a string, rod, or plate of some musical instrument, is set into motion, the untrained listener is conscious of a tonal fusion, a sound in which he does not distinguish different elements of pitch, but hears only the one pitch. The tone which he hears may, to be sure, be different from that which he would hear if the string vibrated only as a whole; but he knows this difference (if, indeed, he is aware of it at all) as voluminousness or timbre, not as a combination of different pitch-elements.* The trained listener, on the other hand, is conscious of a unity of differentiated elements ; and among these he recognizes not a single pitch, but several. These distinct elements of pitch are due to the fact that the vibrating body \ibrates both as a whole and also (more swiftly) in sections.!
It thus appears that, for the trained listener, consciousness of harmony, that is, of a unity of different pitch-elements, is produced by the vibration in sections of a single vibrating body. In place of a fusion he experiences that combination of a lower, stronger tone, the fundamental, with one or more higher tones called overtones, partials, or harmonics. The
lowest of these overtones is always at least an octave higher than the fundamental, ilial is to say, its vibration-rate is twice as great. For exam]^le, if the C-string of a violin be vibrated, the trained listener may hear a combination of the pitch-element C, its octave c, the g above the octave, and the c, e, and g of the next higher octave.
(2) But untrained as well as trained listeners are conscious of harmony when, in the second place, combinations of airwaves are due to the simultaneous vibration of several different bodies, instead of being due to the sectional vibration of a single body — string, rod, or plate.* The consciousness of harmony is, in fact, physically conditioned by a combination of air-waves such that their vibration numbers stand to each other in uncomplicated ratios as 1:2 or 2:3. The vibration ratios of the modern musical octave are : —
The so-called perfect intervals are accordingly: the octave (C-c), the fifth (C-G), and the fourth (C-F), with vibration ratios of i : 2, 2 : 3, and 3 : 4, respectively. (To the untrained listener the octave, even when produced by the vibrations of different bodies, is ordinarily a fusion, not a harmony — in other words, the two pitch-elements are not distinguished.)
Besides these perfect intervals or experiences of harmony, there are also the 'imperfect intervals' conditioned by the major third (C-E), the minor third (C-t?E), the major sixth (C-A), and the minor sixth (C-t^A), with vibration ratios,
The Consciousness of Rhythm and of Melody 83
rcs])ccti\'cl}-, of 4 : 5, 5 : 6, 3 : 5, and 5 : S. In tlirsc c\])CTiences the consciousness of the difference of the tones is rehiti\ely eni])hasi/e(l. W'lien tliis consciousness of difference obliterates, or almost obliterates, that of unity, the agrecableness characteristic of the consciousness of harmony disapj^ears, and we have the experience of discord or disharmony, conditioned bv the union of air-waves of complicated xiljralion-ratios.'" The principal discordant intervals, with their vibration-ratios, arc the major second (C-D), the minor second (C-f?D), the major seventh (C-B), and the minor seventh (C-;^B), with the vibration ratios 8 : q, 15 : 16, 8:15, g : 16.
The nature of the physiological processes, excited in the end-organs of the ear by these combinations of air-waves, and the nature of the cerebral processes, assumed to condition the experiences of unity and of difference, are still tojjics of conjecture rather than of established hypothesis. The occurrence, however, of the consciousness of the harmony of different tones is indisputable.
One is conscious of rhythm*- in dancing, reading poetry, playing an instrument, and in watching the dance and listening to poem or to music* Such an experience of rhythm is a consciousness of the regular alternation of temporally distinct sense-phenomena, either bodily movements or sounds. It is based on the alternation of regularly varying bodily processes — in particular, on the alternations of short inspiration with long exjMration, and of strong with weak pressures in walking. To quote from Professor Titchener : ".\swerun
or walk, the legs swing alternately, and with each leg swings the arm of the opposite side. Here we have the basis of the idea of rhythm; a strong sensation-mass from the leg whose foot rests upon the ground, the leg that carries the weight of the body, followed at equal intervals by a weak sensation-mass from the leg that swings through the air. ... As the leg swings, the arm swings; and at the moment that the foot is set down, the arm pulls with its full weight upon the shoulder. . , ." *
These natural tactual rhythms are, however, mere alternations of two bodily phases. Dance-rhythms and auditory rhythms — regular alternations of sounds, weaker and stronger, longer and shorter, are capable of much greater variation and are consequently far more complex. The unit of musical rhythm is a measure; measures are combined in phrases; and phrases are grouped in musical periods. The unit of word-rhythm is a poetic foot; and verse and stanza are progressively complex combinations of poetic feet. The consciousness of these more complex rhythms is an experience of group within group.
It is important to observe that auditory and motor rhythms are normally combined. The chorus-dance, out of which the drama developed, is an expression of this close relation between the sensory and the motor nerve structures, which we illustrate whenever we keep time, with hand or foot, to music.
The consciousness of melody is a complex experience of a rhythmic series of harmonious tones in which the harmony is successive, not simultaneous. As in the case of the rhythmconsciousness, the unified terms are temporally distinct.
Fundamental, therefore, to both experiences, that of rhythm and of melody, is the consciousness of time, an unsensational experience which will later be discussed.*
The study of all these forms of perceptual unity shows clearly that in perception and imagination the consciousness of unity and of difference is combined with a limited grouj) of sense-elements — that is, with a part only of the total sensational experience of the moment. Another way of stating this contrast between the sensational experience as undifferentiated total and perception as limited complex is in terms of the oljjcct of each. The merely sensational consciousness conditioned by any combination of physical stimuli has an object, the undistinguished mass of colors, sounds, pressures, and the like. The perceptual consciousness conditioned by the same stimuli has differentiated objects.^ The distinction may be illustrated by comparing my consciousness at this moment with that of the baby whom I am holding in my arms. His sensational consciousness may be as rich as my own, for he is sensationally conscious of a totality of colors, brightnesses, bignesses, tones, and noises; but he has not yet the perception of objects. The object of his consciousness is, rather, in the often-quoted words of James, a ' great, blooming, buzzing confusion of undistinguished colors and sounds.' This is an experience which the adult occasionally approximates — for example, when he enters from the dark a brightly
lighted room and no object stands out from the dazzHng confusion of hght and color;* or when, in his first waking moments, he is vaguely conscious of colors, warmth, pressures, and sounds which, as he slowly wakens, seem to range and round themselves into wall, furniture, bed-coverings, and knock-upon-thc-door. In a word, perception, like imagination, is the consciousness not of an undifferentiated totality but of differentiated objects. And the differentiation, the realization of different groups of qualities as making up each distinct object, is plainly due to the habitual occurrence of certain experiences in close connection. So, when the experiences of wetness, whiteness, warmth, and sweetness have often enough coincided, the baby has the consciousness of milk; and when the experiences of redness, softness, w^oolliness, and roundness have often enough occurred together, he is conscious of the ball. The outcome of this chapter is, then, to amplify the account of perception and imagination by regarding each as the fusion and assimilation of a limited group of sense-elements with the consciousness of unity and of difference.
Of all so-called external ()l)jects, my body stands in closest relation to myself. It is related also in a twofold fashion to other external objects: through its sense-organs and ingoing nerves it is affected by them; through its outgoing nerves and muscular contractions it affects them. Indeed, the physiological process initiated by the excitation of a sense-organ is unfinished until it is terminated in a muscular contraction; in other words, a complete physiological process is neither sensory nor motor, but sensori-motor.*
It was shown in Chapter TIT. that the different modes of sensational experience — visual, tactual, and the rest — are marked off from one another not only by the excitation of different end-organs and of different cerebral areas, but by the characteristic bodily movements — of eyeball, hand, and tongue — which accompany them. This chapter will treat of perceptual bodily reactions and will describe them
* The student is advised to read, in connection with this chapter (i) on sensori-motor reactions : J. R. Angcll, " Psychology'," Chapter III. (2) On habit: W. James, "The Principles of Psycholog)'," Vol. I., Chapter IV., or " Psychology, Briefer Course," Chapter X. (3) On instinct: C. L. Morgan, " Animal Life and Intelligence," Chapter XL, or " Comparative Psycholog)'," Chapter XII., or James, "The Principles of Psycholog>','" Vol. II., Chapter XXIV., or " Psychology, Briefer Course," Chapter XXV.
(i) The perceptual reaction is distinguished as coordinated, or unified, from the merely sensational movement. The significance of this distinction will be clear if one contrast the behavior and the probable consciousness of a little baby with that of an older child in the presence of a visual object — let us say, of a woolly red ball. The older child fixes his eyes upon the ball, follows it, if it is moved toward one side, by his eyes and his turning head, and seizes hold of it if it is within reach. The week-old baby, far from fixating it, does not ev^en converge his eyes upon it, for each eye still moves more or less independently of the other ; he does not turn his head toward it if it is moved away ; and though his hands move aimlessly and may accidentally strike the ball, the two hands do not meet on the ball, and there is no coordination of the complex movements necessary for seizing it. Yet the baby is reacting to the ball : his eyeballs make more movements, his hands flap more wildly than before the ball was held and moved before him. Such a reaction, sometimes called an 'excess-reaction,' is due to the diffusion of incoming nerve-impulses over outgoing nerves and muscles. It differs as widely from the unified and coordinated movement characteristic of perception as the sensational consciousness of redness differs from the perception of a red object.*
(2) Perceptual and therefore coordinated bodily reactions tend, in the second place, to be repeated, that is, to become habitual. My reactions, at different times, to the same object or class of objects are closely alike. I make the
same jaw-movcmcnts whenever I eat, and I hold and move my pen in the same fashion every day. These habitual movements are, it should be noticed, of twofold origin — instinctive or acquired.* * My pen-mo\'cments have been acquired, that is, learned. The movements which I make in eating are, on the other hand, instinctive; and this means that they are not acquired. So, a baby instinctively moves its hands and eyes, but it acquires the movements of convergence and of grasping with both hands; and a duck instinctively enters the water, but learns Ijy imitation to drink. Instinctive reactions are racially hereditary and are severally characteristic of different animal groups. By far the greater number of them become habitual, but some instinctive acts — for example, the egg-laying of certain insects — are but once performed. Instinctive reactions may be classified, further, as movements of withdrawal or of approach ; and movements of approach are either antagonistic or cooperative. Acquired reactions are of two main types : movements learned by imitation and reactions learned through purely individual experieftce."
(3) From the habitualness of the perceptual reaction follows a noticeable character : its relative immediacy. The reaction which accompanies not only perception but also many forms of imagination, and even certain kinds of thinking, is relatively immediate as compared with the reactions distinguishing reasoning and choice. The distinction between immediate and delayed activity is, to be sure, relative and not absolute, but is readily made between extremes of the two classes. Hold out an apple — or, for that matter, a cateri)illar — to
a baby of eight months: he will ])rom])tly seize it and carry it to his month. Offer the same dainty to a three-year old: he will hesitate. Memories of disagreeable tastes or of sharp penalties vie with the impulse to grasp at every object; his response, whether of advance or of withdrawal, is hesitating and delayed. The dog's response is immediate : he barks, he leaps up into the air, he runs madly around the room. For several minutes the boy makes no obvious motion ; then he slowly piles footstool into chair, climbs up and tries to open the cupboard door — again a case of delayed as contrasted with relatively immediate reaction. These are examples of advantageously delayed reactions. In many situations, on the other hand, immediate perceptual reactions, to dangerous or to momentarily favorable environment, are of crucial importance for the individual and for the race.
(4) The observation that the perceptual reaction is relatively immediate must not lead to a confusion of it with the reflex reaction. A reflex act is an act which follows on a stimulus without intervening consciousness. It may be consciously performed; in other words, it may be accompanied by consciousness, but it is not excited, or invariably preceded by, consciousness, I sip my coffee at the sight of the brimming cup and I move my fan to the sound of the music, that is to say, a unified consciousness of the object precedes my reaction to it. In technical terms, my perceptual reaction is impulsive, not reflex; although the consciousness of reaction is a constituent of the complete perception.
The Bodily Reactions in Perception and Imagination 91
handkiTcliicf when one has dropped it is an impulsive act following on the consciousness of it as it lies on the ground ; to throw one's handkerchief to the lions (after the fashion of the lady in the i)oem), that one's lover may risk his life to snatch it from them, is a volitional act. Or, again, to j)ick up mv cards from the table is an impulsive act, whereas to discard from a strong and not from a weak suit is a volitional act. The distinction is readily stated. Both perceptual and volitional reaction arc conditioned by consciousness; in technical terms, both are ideo-motor acts. But only the volitional, not the perceptual, act is planned or anticipated. 1 do not say to myself: "I will drink this coffee, or move this fan," but the bare sight of coffee or of fan excites the habitual reaction. The perceptual reaction is sometimes, indeed, opposed to my will. For example, I may drink the coffee in si)itc of having definitely planned to delay coffee-drinking unfit after taking my tonic ; and I may find myself moving my fan, even though I am deeply principled against keeping time to music.
I. The Nature of Attention
Every one knows that there is a distinction between attention and inattention* Our special problem, at this stage of our study, is the nature of attentive perception and imagination; but even now we realize that attention is a factor also of other experiences. We may profitably begin our study by an illustration of perceptual attention. Suppose that I am perched on a rock, on a sunny September afternoon, lazily looking off upon a quiet sea, dotted here and there with gleaming sails, some near the shore, others on the liorizon. I am awake and open-eyed, receptively and sensationally conscious. In a word, I am perceiving. Now supj)Ose that a sloop comes into view around the rocky headland at my left, I am no longer im])artially conscious of sea and of boat ; nor do my eyes wander idly from horizon to shore and from shore to horizon again. Rather I bend forward and fix
* Before reading farther, the student should answer, in writing, the following questions: (i) Name two things to which you naturally (without training) gave attention. (2) Name two subjects to which you have learned to attend. (3) What bodily movements anfl attitudes characterize your attention to a faint sound ? (4) What bodily movements and attitudes characterize a dog's attention to a faint sound? (5) Describe, in full, your attentive consciousness (a) of the irregularity in contour of the period at the end of this sentence; and (6) of the boundaries of the state of New York (as you now, in imagination, bound the stale).
my eyes uijon the sloop ; or, to use the everyday expression, I concentrate my consciousness on the boat and, so long as it remains in view, I am not in the same way conscious of anything else. In other words, I attend to the boat. And tomorrow, when I am altogether unable to tell whether the rocks in the foreground were brown or gray and whether the sky was clear or cloudy, I shall remember that the boat was a yawl-rigged schooner with a black hull.
But though it is relatively easy to describe an attentive experience, its bodily accompaniments, and its psychic effects, it will be found impossible to define that special factor of the experience which is known as attention.^* Rather, as most psychologists implicitly admit, attention is an elemental, a further unanalyzable and an indescribable sort of consciousness. We realize it best by contrasting it with the inattentive consciousness, for example, with the drowsy consciousness, or with our normal consciousness of objects which stimulate only the outer zones of the retina. But we cannot define attention or reduce it to more elemental constituents. Attention — is just attention.
One further statement may be made. Attention, though elemental, seems not to be sensational.^ On the side of physiological condition it is distinguished by the lack of any specific end-organ; and, apart from this physiological distinction, attention differs from sensation by being sometimes present, sometimes absent, from our consciousness. In other words, we sometimes attend and, again, we are inattentive, whereas we are always sensationally conscious even when, as is usual, we are more-than-sensationally conscious.
cannot describe attention, even though we know what it is,
— our further study will turn out to be mainly a study not of attention itself Init of its objects, conditions, and results. We may well begin by considering the objects of attention ; and three important statements must be made about them. {a) We may attend, in the first place, to objects of any kind
— personal or imj^ersonal, jniblic or private, externalized or non-externalized, sensational, afTective, or relational.^ In more concrete terms : my attention may be centred on myself or on my friend — personal objects, the one private, the other public; again, my attention may be directed to Botticelli's " Pallas," or to the emotion with which I regard the picture — both impersonal objects, the second private and non-externalized, the other public and externalized; I may attend, finally, to the binomial theorem or to my lead pencil — both impersonal and public objects, but the last only externalized. It follows that all kinds of consciousness, perception and emotion, thought and will, may be ' attentive,' accom])anied by attention. Certain forms of consciousness are indeed, as will appear, necessarily and inherently attentive.
{h) The object of attention is, in the second place, always a relatively stable, or persistent, object. In inattentive perception, my eye moves from object to object; in inattentive imagination, one image follows on another in a swift succes-
sion. In attentive perception, on the other hand, my eyes are hxed on the unmoved object and move only to follow the moving thing; and in attentive imagination I linger over the imaged object or scene. In apparent opposition to this teaching, stress is sometimes laid on a fluctuation in objects of attention : it is asserted that one cannot attend longer than a few seconds to any sense-object. But though it is true that the fixated color grows alternately bright and dull, and that the sound to which I listen is now loud and again soft, yet these phenomena, classed as fluctuations of the objects of attention, are really only fluctuations in the intensity of sounds, colors, and the like. Such fluctuations are partly explained, perhaps, by oscillations in the contraction of the muscular apparatus of sense-organs, but are mainly due to 'the oscillatory character of psychophysical processes in general ' * — to the rhythmic changes, for example, in blood pressure.
It should be added that the object of attention may be stable, or prolonged, while yet attention may be relatively unstable. The object of attention is always stable in comparison with a similar object of the inattentive consciousness — for example, if I attentively observe a tree from a carriage, I turn my head and prolong my view of it. But my attention during this drive may well be more unstable, that is, interrupted by inattention, than the attention with which I sit rapt by some great ])icture. In its extreme form, prolonged attention is absorption, a complete merging of oneself in the object of one's consciousness so that the restless flow of consciousness is checked and the world narrows to the observing self and this one object. Esthetic, logical, and purely
ing consciousness.
{c) The object to which I attend is, in the third place, a part only, not the whole, of the total object of my consciousness at any moment. Thus, to recur to our initial example, I do not attend simultaneously to rock and ocean and sloop. On the contrary, while I attend to the bellying. Happing canvas I am inattentively conscious of the sea and of the rock. Or, to take another example, I attend not to the whole side of the room but to the desk; perhaps not to the desk but to the polished brass inkstand; or, finally, not even to the whole inkstand but to its carved griffin-top. I may even attend to a single inseparable element or factor of a given object — to the redness of the rose, to the novelty of my surroundings, to the pleasantness of my emotional experience, to the causal connection between stimulus and movement.
No exact limits have been so far set by experimental observation to the complexity of the object of attention. In general, any group of terms which can be unified can be attended to. Experimenters, as well as every-day observers, have concerned themselves with this problem, and have i)roved abundantly that small objects, too numerous to be separately attended to, are attentively jjcrceived if combined into a pattern or scheme. If, for example, one drop a screen for less than one quarter of a second (an interval so short that it excludes eye-movements), thus exposing a surface on which five or six small crosses have been drawn, in irregular order, one will find that attentive observers often fail in telling the number of the crosses, whereas they can reproduce the figure
made by the crosses. This shows that the observers attended not to the single figures (the crosses) but to the complex figure, or scheme, composed of all the crosses.* About half a dozen small objects can thus be unified and attended to. Some psychologists believe that we may attend also to two (or at most to three) independent objects; and to the introspection of the writer this seems true. One may train oneself, for example, to attend simultaneously to a fixated visual object and another object seen in indirect vision; and it is impossible to unify these. Most cases, however, of so-called 'divided' attention are either instances of the simultaneous occurrence of attentive consciousness and a merely reflex action, — as when one writes a letter while one mechanically hums a tune or repeats a series of numerals, — or else instances of alternating attention. Julius Caesar did not really dictate four letters while writing a fifth, but his attention vibrated from one to another; and the phenomenal chess-players shift their attention from one to another of the games which they are said to play ' simultaneously.' t
Attention to part of one's total object of consciousness of course implies inattention to the rest. The 'absent-minded' person, who is blind and deaf to the sights and sounds of his environment, is inattentive to them precisely because he is attentive to something else, for example, to some imagined scene or more ideal project. The narrower the object of my attention, the more 'absent-minded' I become. Sometimes, indeed, this negative aspect of attention, the glaring inatten-
* For other experiments, cf. L. Witmer, "Analytic Psychology," p. 54, Exp. XVI.; Titchener, § 38, p. 113 (4); Seashore, p. 165 ff. t For experiment, cf. Seashore, p. 164.
attcntiveness.
((/) The discovery that one attends to a part only of the total object of consciousness at once suggests the question: To what part ? The answers to this question may, perhaps, reduce themselves to three. It is a matter of common observation that I attend (i) to the pleasant or unpleasant — for example, to the compliment which some one pays me or to my toothache ; and (2) to the novel, or unusual, for example, to the figure of a turbaned Hindu in an Oxford audience which fills the Sheldonian theatre. My attention to a sensationally intense object, for example, to a thunder-clap, and my attention to a moving object, for example, to a flying bird or to a moving signal, are cases of attention to the surprising or unusual. B inally (3) I attend to that part of my total field of consciousness which is connected with other objects of my attention. If I am studying the problem of immigration from Southern Europe I notice the most casual newspaper references to Slavs and to Italians, and I remember the southern type of this or that face in a crowd. If I have hurried the carpenters out of the house which they are building for me, by helping to fill with putty the holes left by the nails in the woodwork, then for weeks I mark the variations of color between wood and putty in the wainscotings and furnishings of the houses which I visit. No one of these three characters invariably distinguishes the object of attention — one may attend to the dull color or the soft sound ; an object closely connected with our ordinary interests may be unattended to; and finally — though psychologists arc not in agreement on this point — one may attend to an object which is neither jjleasant nor unpleasant.
But though the object of attention is not inevitably distinguished by each of these characters, it is probably always describable in at least one of these ways : it is pleasant or unpleasant, or else novel, or it is closely connected with experience.
Attention
A common classification of attention is as (i) natural or instinctive, and (2) acquired. It will be observed that this distinction does not imply any difference in the nature of the two sorts of attention. Natural and acquired attention do not differ at all, regarded merely as attention. The dift'erence lies simply in the fact that attention of the first sort is instinctive, untaught, whereas attention of the second sort is acquired through individual experience or through imitation.* All natural attention is evidently, therefore, involuntary. Acquired attention is either involuntary or voluntary, that is, willed. To illustrate: five minutes ago I was instinctively attentive to the whistle of the incoming steamer ; whereas I willed my present acquired attention to this chapter on attention. If I were attending neither to the whistle nor to the scientific discussion, but to a thrilling page of some novel, my attention would be acquired, indeed, — for a printed page is not naturally interesting, — but involuntary. Natural attention is in fact directed to objects which are unusual, pleasant, or unpleasant. The objects of acquired attention are, directly or indirectly, connected or associated with these. We have, thus, the following classification of attention as —
Voluntary J with an object naturally attended to.
The relation between will and attention, which is sometimes denied, will be further discussed in a later chapter.* It is, however, immediately clear that acquired attention is of great practical significance. If our attention were purely instinctive, we should go on through life enlarging our primary childhood interests — absorbed in the objects, brilliant, novel, or pleasant, of our immediate perception. We acquire new interests through our ability to compel ourselves to attend to what is normally uninteresting and unattended to. Thus, voluntary attention attests the power of intellectual development. As Professor Barrett Wendell says: "The practical aim of a general education is such training as shall enable a man to devote his faculties intently to matters which of themselves do not interest him. The power which enables a man to do so is obviously the power of voluntary, as distinguished from spontaneous, attention."
Of the bodily conditions of attention there is little to be said. There are evidently no end-organ excitations of attention. And though we are justified by physiological analogy in postulating some special neural condition of attention, the physiologists speak in vague and more or less divergent terms of the nature of such a neural process. Some sort of special 'preparedness of brain-centres' must be assumed to exist. The characteristic muscular contractions which ac* Cf. Chapter XIII., i>. 227.
company attention arc more readily described. They arc of two sorts : in the first place, contractions, usually instinctive, of the muscular apparatus of the sense-organs, tending to adapt these organs to the conditions of distinct consciousness. For example, wc instinctively change the convergence or the accommodation of our eyes in order to obtain a distincter outline of the object which interests us ; we turn our heads toward the source of the music to which we are attending ; and we follow a moving object with our eyes. Muscular contractions of this sort are, of course, peculiar to sense-attention. A second class of muscular contractions is characteristic of all sorts of attention — such contractions, namely, as prevent disturbing movements of any sort. The rigidity and stillness of the body is, indeed, an obvious accompaniment of attention.
In the successive sections of this chapter attention has been described as elemental 'attributive' consciousness; the object of attention has been distinguished as a relatively stable part of the total field of consciousness and as sensationally novel, or affectively toned, or associatively connected; attention has been distinguished as instinctive or acquired, involuntary or voluntary, and, finally, the bodily correlates of attention have been indicated. It remains to speak briefly of what may be named the results of attention. First and most important is the normal recurrence of the attentive consciousness. In concrete terms, we are likely to remember what we attend to, and, conversely, we forget what we inattentively experience.*
Tlic Classes, Conditions, and Results of Attention 103
imagining; it forms, in a word, the starting-point of association. The next chapter will lay more stress on the relation of attention to association.* Here wc need merely name and illustrate this connection. Not the whole experience of a given moment, but the emphasized, that is, the attentive, part of it is likely to form the starting-point of my imagination. For example, my outlook on the view from my window is probably followed not by the imagining of a closely similar landscape, but by the imagination — let us say — of a lighted Christmas tree due to my attentive consciousness of the evergreen tree near my window. Attention is thus a condition alike of association and of retention. The chapters which follow will make this more evident.
A word should be said, in conclusion, of the relation between interest and attention. The term ' interest ' is best used as synonym for involuntary attention. I am interested in the objects to which, without effort of will, I attend.
I. Productive and Reproductive Imagination
This chapter is devoted to the study of imagination from a new point of view.* Imagination has, up to this point, been described as sensational, unifted, and 'private' consciousness of particularized objects, and has been classified according to sense-types. We are now to take account of the distinction, practically and aesthetically significant, between reproductive (or recurring) and productive (or inventive) imagination. Relatively accurate and complete reproductive imagination is called memory.
It must at once be noted that the 'structural elements' of imagination always are reproduced (that is, repeated) and not in any sense 'novel.' They are part of our original endowment, instinctive forms of consciousness, as we may call them. I can imagine no brand-new color, and no new taste. The novelty involved in so-called creative imagination is therefore a novelty of combination, for one complex experience may differ from every previous one, though, taken singly, no ele-
* Before reading farther, the student should answer, in writing, the following questions: (i) What seems to you to be the difference between imagining and remembering? (2) What method would you use in order to memorize (u) the objects in a Jeweller's window? (6) a Shakespearian sonnet?
mcnl or part of the ' novel ' experience is new. Every instance of creative imagination illustrates this statement. Jn imagining a centaur, one combines the image of a man's head with that of a horse's body; in inventing the telegraph, Morse prolonged in imagination the image of charged wire, and united it with that of vibrating lever and writing point. These are instances of the combination of images in themselves far from simple. The parts combined may, however, be much less complex — mere elements or very simple images.
The forms of imagination thus provisionally illustrated must be more closely considered. Of creative imagination two main forms are ordinarily distinguished : the mechanical and the organic. The mechanical image is a complex, not of qualities, but of relative totals, of experiences complete in themselves, as if a painter were to paint a picture of Tuscan olive trees on a New England hillside. The organic image is a complex of single elements or of fragmentary aspects of different objects, which fuse into a new whole of organically related parts. Within the class of organic imagination one may distinguish, also, the fanciful from the uni\ersal imagination, on the ground that the first lays stress on more or less bizarre and accidentally interesting characters, the second on essential, universally appealing qualities. Thus, Kipling's description of the "Workers" includes a bold fancy : —
The study of reproductive imagination will involve us in more detail. It has already been classified as complete or incomplete, accurate or inaccurate. These are relative terms, and it is probable, of course, that no case of literally complete and accurate reproductive imagination ever occurs. Practically complete and accurate imagination is called memory and is, as everybody knows, a significant factor in conduct and an indispensable basis for thought. The questions, " How do I remember?" and "How may I foster and, if possible, increase my chance of remembering?" assume, therefore, a practical importance of high order. The admitted answer to the first of these questions is as follows: "I remember through association." The meaning of this term we have next to discuss.
Successive association is the sequence of an imagination on a perception (or another imagination), a sequence which is attributed (in after-reflection) to the previous occurrence, simultaneously or in swift succession, of the two experiences.**
* The term 'association' is often used in the sense of 'successive' association. For the distinction between 'successive' and 'simultaneous' association, cf. Chapter IV., p. 65, with Note, and Appendix, Section VII. (§ i). The Arabic numerals, throughout the chapter, refer to numbered divisions of the Appendix, Section VII.
The Nature of Association 107
For example, my present memory of a Parisian dinner-table — the brightly lighted salle-a-niaiigcr, the long table, the white-haired hostess — is associated with my present percept of a knock on my door, that is, it follows upon the knock and is exj^lained by the fact that, night after night, just such a mullled tap from the ser\-ant who summoned me preceded my consciousness of the dinner-table.
The most important and obvious classes of association may best be descriljcd by the terms ' total' and ' partial.' * ' Total association' is that between com])lex experiences which are complete in themselves. It is an external and prosaic sort of connection exi)lained as due to the simultaneous or the successive occurrence of 'the same' experiences in the past. The association, one after another, of the imaged notes of a melody, words of a poem, or implements of a trade, are examples of this common form of association which may be readily symbolized by the following diagram : —
cept of dog of master
In this diagram, the small letter (y) stands for 'image' and the capitals stand for 'either percept or image'; the arrow designates the fact and the direction of the association, and the line connecting A'" and 1'" incHcates tliat tlie two experiences
* These terms were suggested by James. The expression 'total' must not, of course, he interpreted as if it required that the entire experience of a given moment should be associated with the imagination which follows on it. On the other hand, the term 'total' covers cases in which the first term of the association is very limited in extent, in which, for cxam[)lc, the first term is the consciousness of a single word.
Partial association is the association of elements of consciousness or of groups of elements. Its most extreme case, which James aptly calls 'focalized association,' is the observed connection between one single element and another elemental or complex experience. This type of association is more varied in form and less obviously attributed to continuity in past experience, and must therefore be considered in more detail.
First of all, let us assure ourselves that the partial association does indeed involve the assumed identity of its terms with past experiences, which were either simultaneous or successive. We may select, as an extreme instance, the association implied in these verses of Shelley : —
"And the hyacinth, purple and white and blue. Which flung from its bells a sweet peal anew Of music, so delicate, soft and intense, It was felt like an odor within the sense."
Now, it is in the highest degree improbable that Shelley had so often or so vividly experienced together the fragrance of hyacinths and the sound of bells that the one should suggest the other. At first sight, therefore, this seems to be a case of association which does not involve an assumed identity of the connected terms with past experiences occurring together. But on closer scrutiny we discover that the actual connection, for Shelley, between imagination of sound and perception of fragrance was the consciousness of the bell-shape of the flower. None of the other elements of the perception of the hyacinths, the consciousness, for example, of their color, their height, their texture, has any connection with the imagi-
nation of the peal of music. But this connecting link, the consciousness of the form of the llowers, is not associated with the ima.^ination of souncUng bells as a whole, for it is itself one element of this imagination; in fact the only association involved is that between (i) the elemental consciousness of * bell-shape,' common to both the perception of the fragrant hyacinth and the imagination of the pealing bell, and (2) the remaining elements of the imagination of the bell, the auditory imagination of j^itch, intensity and volume of tone, and the visual imagination of the color and form of the bell. This will be made clearer through the following diagram: —
of hyacinth shape of bell
Here the Roman numerals, I. and II., represent the total, concrete facts of consciousness, the hyacinth-percept and the bell-image; X is the element common to both (the consciousness of shape) ; y represents the group of elemental imaginings, of pitch, intensity, and the like {m, n, and 0), associated by X and forming with it the image of the pealing bell ; whereas W groups together those elements, the consciousness of color, height, and so on (a, b, and c) of the hyacinth-percept, which have no part in the association. Comparing this, therefore, with the concrete associations, we find that it has the following distinguishing characteristics: first and foremost the
starting-point of the association is very narrow, either a single element or — as we shall see — a group of elements, but never a concrete total. This first term (A') of the association is, in the second place, a part both of the first and of the second of the successive, concrete experiences (the hyacinth-percept, I., and the image of the bell, II.) and the association is, thus, entirely within the second of these experiences, the image of the bell. It follows, also, that only this second one (II.) of the concrete totals of consciousness need be regarded as identical with any former experience; in the present case, for example, Shelley need never before have seen a hyacinth, but he must already have seen and heard a pealing bell, in order to have the association. Finally, it is evident that, in cases of successive association, the first of the associated elements or groups of elements (X) necessarily persists in consciousness, whereas the elements combined with it in the earlier complex (I.) fade gradually away; and that the persisting element is then surrounded by the added elements (m, n, o) of the second concrete (II.). This persistence of the earlier experience, though occurring in concrete association, is especially characteristic of the 'partial' type.
The connecting term of a partial association (the X) may include more than a single element. We have then an instance of what may be named 'multiple association.' When Wordsworth, for example, says of Milton : —
the star reminds him of Milton's soul, not merely by its aloofness but by its light. Or, to take a more prosaic illustration, if the sight of an Italian salt ship calls up an
image of a Roman trireme, the association is not belwt'en consciousness of salt ship and of Roman trireme as total experiences, for I surely have not been conscious of them at one time or in immediate succession on each other. But neither does this association start from any single feature of the perceived ship. Rather, a highly complex combination of elements (falling short, however, of a concrete total) — the consciousness of dark hull, of masts, and of rigging — is common both to the perception and to the imagination; and these factors common to both experiences are associated with the images, cerebrally excited, of banks of oars and Roman ligures, which complete the consciousness of the trireme.
It has thus been shown that the partial, like the total, association is accounted for by the assumed identity of associated experiences with earlier experiences; but that these recurring experiences, instead of being concrete wholes, are either elements or groups of elements, which have been combined in former perceptions or imaginings — of pealing bells and of Roman trireme, for example. An association should always, therefore, be analytically studied. The important point is the determination of its first term, and the common error is the supposition that a complex experience is invariably to be taken as a whole in tracing the associative cbnnection. On the other hand, as we have seen, all subtler associations are instances of association "between more or less elemental parts of total experiences. Undoubtedly the greater number of associations are of the total sort — associations between consciousness of object and of use, between the percept of a face and the image of a name, and between the terms of verbal and motor series. But the
associations which distinguish the imaginative from the prosaic type of mind, which arc the essence of all metaphor and the very heart of humor, belong, all of them, to the ' partial' type. No opposition is too fixed, no separation of time or place too wide, to be bridged by this sort of association.
ASSOCIATION
I. Total or Concrete Association, of complete experiences (with or without persistence of the iirst term). II. Partial Association, of persisting elements of consciousness: —
Before taking up the more practical question of the definite direction of association, two theoretical comments must be made. It must be pointed out in the first place that one's experiences never recur, in the sense that the percepts or images of one moment are actually identical with those of a preceding moment. On the contrary, my present image of Faneuil Hall, of my uncle, or of tlie date of the fall of Khartoum is quite a different event from my earlier perception or image of the same building, person, or date. Unquestionably, however, I assume a certain ' recurrence ' of the past experience, and this assumed identity or recurrence is rightly recognized by the psychologist as a character of association. A further discussion of the possibility and nature of recurrence would be metaphysical.
the study of association involves the distinction, already discussed, between (i) my subject-self, the unique and persisting subject of complex experiences; and (2) these same experiences regarded as impersonal, though not externalized, objects belonging to a special point of time. Such a treatment ])rovcs to be necessary to adequate psychological description. It is dangerous only if one forget that the distinction of subject-self from its experiences is an abstraction — that the experiences never occur except as experienced by a self and that a self is not absolutely divorced from, or opposed to, but rather inclusive of, these experiences.
III. The Direction of Association
The discussion of association has thus made evident the close interweaving of partial contents of our complex total experience. It is evident that when one of these partial experiences ' recurs,' as perception or imagination, some other, previously continuous with it, recurs also, as imagination. A very vital question concerns the actual direction of association. Given a recurring perception or imagination, it has perhaps already occurred a score of times in as many different connections. Which, then, of the images that might conceivably follow on it will actually be associated ? If, for example, the sight of a topaz necklace is the starting-point of the association, will it be followed by a vague imagining of Delhi, from which it came, by an imagination of the crown jewels in the Tower of London, or fmally l)y some mainly verbal image — the image, for example, of the words ' topaz necklace ' or of the verses —
Obviously, it is of practical importance to learn, if we can, the principles according to which one image rather than another is associated ; for thus we may increase the chance of recalling what is useful or pleasant rather than the indifferent or harmful parts of our earlier experience. Now experiment confirms the every-day observation that experiences are likely to be associated in proportion as they are (i) naturally interesting or (2) frequent or (3) recent.* By naturally interesting experiences are meant those which involve instinctive attention, and it has appeared already that the objects of instinctive attention — so far as they can be characterized — are sensationally intense, or novel, or affectively toned. Two sorts of frequency, also, should be distinguished. An experience may occur frequently in the same connection — for example, a bell may ring thirty times a day, always by pressure of the same button ; or the experience may recur frequently but in different connections — for example, pressing a button, turning a handle, and working a treadle, each a dozen times a day, may ring the same beU. Recent experiences need not be further classified.
We may readily find examples of associated imaginings of these different sorts.^ If the sight of the necklace suggests the words ' topaz necklace, ' it is because of the frequent connection of visual impression and words; if, on the other hand, it reminds me of the verses, this is because I was last night rereading "The Miller's Daughter" ; if it suggests an imagination of Delhi or of the crown jewels, it is because these are images inherently interesting through sensational intensity or
* Similarly, it is true that, of the percepts or images of a given moment, the suggestive one — that which forms the starting-point of association — will be interesting, recent, or repeated.
The Uses and Methods of Memorizing 115
through emotional thrill. Or, to take another illustration : if the si<j;ht of a surrey, with yellow awning, reminds me of the carriage in which I drove from landing-dock to hotel, in Gibraltar, this is because the Gibraltar experience was very vivid — sensationally novel and intense as well as markedly ])leasant; if the surrey, however, reminds me of the rugged Maine farmer who drives it, this is because he yesterday drove me to Bar Harbor in it; if, finally, it reminds me of a prosaic train-hack, this is because my most frequent drives are to and from railway stations.*
The practical ai)jjlications of these principles of association will be referred to again in the concluding part of this chapter. The discussion of this section may be concluded by a brief statement about the probable physiological explanation of association. In a general way it may be said that the physiological condition of association is the excitation of intra-cortical fibres connecting different cerebral areas. The larger these connected brain-areas, the more nearly 'total' is the association ; and the more continuous the cerebral excitation, the more persistent is the consciousness. It is also natural that connecting fibres which have been frequently or recently or strongly excited should offer little resistance to the excitation ; and in this probability we have the suggestion of a ])hysiological basis for the secondary laws of associative frequency, recency, and interest.
in creative imagination I reach out also beyond the limits of past and present. As a merely perceiving self I am bound to this desk, this loom, this ])lot of ground ; but as a remembering self I live through, once more, the exhilarating adventures and the beautiful scenes of my past experience, and as a creatively imagining self I am hampered neither by 'now' nor by 'then.' I go beyond my own actual experience, I see visions, I dream dreams, I create new forms. In Stevenson's words : —
Evidently, therefore, we shall wisely seek to foster both memory and creative imagining. But it is plain at once that one cannot directly will novelty or spontaneity or independence in imagining; and that one may as well try to harness Pegasus as to frame rules for the fancy. In other words, the cultivation of imagination is limited to the cultivation of memory — the effort to reproduce accurately and vividly. Indirectly, indeed, this cultivation of the memory lays the foundation, as it were, for creative imagination and fancy. In other words, memory is not a mere end in itself, and we memorize not only in order to re-live our past experiences, but in order to become capable of new ones. For all creative imagining, as has appeared, consists in the novel combination of the reproduced images of color, sounds, and movements, or of words. The creative suggestion, the flight of fancy, follows only on the vivid and faithful reproduction of the actual experience; and imagination, lacking this accuracy and fidelity, is insignificant and ineffective. Thus, the truly imaginative poet is endowed
with what Lcwcs called ' vision, ' and his work is distinguished by "great accuracy in depicting things ... so that we may be certain the things presented themselves in the field of the poet's vision and were painted because seen." *
Not only creative imagination but all forms of thought are based on memory. Thus, 1 could not generalize without memory — for cxamj^le, I could not be conscious of chairs as a class, if I could not remember different sorts of chairs which I have seen ; and I could not reason — for example, I could not reason out the solution of an algebraic problem — if I could not remember the values, once learned, of the different terms. Now analytic reasoning and creative imagination are the two psychological forms of learning, that is, acquisition of new experience ; f and it is therefore true that memory (though in itself a preservation of old experiences) is essential to learning. Even physiological learning, the acquirement of new bodily dexterities, is dependent on memory ; for the old instinctive reactions would be repeated again and again — the lish would always snap the hook and the child would invariably touch the flame — but for memories of the painful results of such activities.
Obviously, therefore, it is well worth our while to concern ourselves with methods of memorizing; for, despite great individual differences in the ability to memorize, experimental investigation has failed to disclose any one utterly incapable of improving his memory. On the contrary, unexpected capacity for improvement has been brought to light. In a long series of experiments carried on in the Wellesley College
laboratory * one subject was trained to reproduce correctly series of eighty-one colors or odors or nonsense syllables; another learned to reproduce series of sixty-one terms; and no subject failed to show some improvement through practice.
Methods of memorizing have been formulated on the basis of the principles of attention and of association/ These methods vary somewhat according as one seeks to memorize one fact or many, and according as one wishes to memorize facts as ordered or facts irrespective of order. Certain conclusions, however — one may perhaps call them rules for memorizing — emerge clearly from the experimental study of methods. t The first of these has already been stated: One should attend to that which one wishes to remember. To promote memory one must, therefore, observe with attention ; to secure the recurrence of an experience, one must concentrate oneself upon it. A classic illustration of the dependence of memory on attentive apprehension occurs in Wordsworth's "Daffodils": —
* Cf. "A Study in Memorizing Various Materials by the Reconstruction Method," by Eleanor A. McC. Gamble, Psychological Review Monograph Supplements, Psychological Series, No. 42, 1909. The remaining portion of this chapter is based, in great part, upon the experimental investigation and the conclusions of this book.
The second rule for mcmorizinf:; is designed to meet a difficulty in attentive apprehension due to the multiplicity of objects which it is desired to attend to, and thus to remember. Attention, it is e\-ident, should be directed to those parts of a complex or of a series which are normally most often forgotten. So far as series are concerned, ordinary observation and experiment alike disclose the fact that the middle part of a series is most likely to be forgotten — a fact readily understood when one remembers that the first of a series has a certain interest, and that the last of a series possesses the advantage of recency in experience. It is evidently, then, expedient to direct one's attention toward the middle of the series — experimental indications point to the part just beyond the middle. Thus, if one is trying to visualize a series of the colors green, gray, brown, pink, blue, white, red, black, mauve, the attention should be directed not to green and gray, nor to black and mauve, but to blue and white.
Another method for attending to a group of facts is recognized by the third rule for memorizing: single facts to be remembered should be grouped or unified. Words, for exami)le, are most readily remembered as linked in sentences or in stanzas; and the streets in a city or rooms in a building are best recalled as related parts of a map or plan. Even meaningless material, if one is trying to remember it, should be grouped — nonsense syllables, for example, in rhythmical measures, or colored papers in blocks of three or four. Indeed, every-day observation shows that facts of any sort are best remembered when grouped. Thus, I learn the date, 1690, of the jHililication of Locke's "Essay" by connecting it with the date, 1688, of the coming of William and Mary anfl with the fact that Locke returned from his exile in Holland on
the ship which Ijore the Princess of Orange; and I connect the invention of printing and the discovery of America with the late fifteenth century by regarding both as manifestations of the renaissant spirit of adventure.
The fourth rule for memorizing follows from a principle of association: that an experience occurring frequently in different connections is the more likely to recur. If the professor of economics and the professor of German and the professor of ethics alike quote Nietzsche in their lectures, I am likely to be reminded of Nietzsche more often than if he were favored by one only of my teachers. It follows that one should emphasize existing connections and form new connections of the fact-to-be-remembered with other facts likely to recur and to suggest it. This rule, though important, needs to be guarded. For, first, the greater the variety of facts indirectly or directly connected, the greater the likelihood that, in a given situation, an undesired image — or no image — will recur. If the nonsense syllable mej appears in the fifth place of a series which I am trying to learn, the fact that it has held second place in yesterday's series and eighth place in a last week's series makes it likely that, on trying to repeat to-day's list, I assign we; to second or eighth, not to fifth, place, or that I am altogether doubtful of its position. The formation, in the second place, of artificial connections is commonly of very questionable value, for such connections lack the very conditions of associative recurrence. It is futile, for example, to .transfer one's ring to the middle finger for the sake of reminding oneself to wind the clock. Clock-winding and ringon-third-finger are not normally connected in my experience, but occur together seldom, and there is therefore little likelihood that the sight of the ring, a few hours hence, will recall
precisely the image of clock-winding. Indeed, the artificial auxiliary image, expressly formed to suggest some other image, has a pertinacious way of absorbing attention and thus of preventing the association desired. If I try to remember Mr. Saltmarsh's name by ' connecting' it with the term ' Freshmeadow,' I am more than likely to strain our relations by calling Mr. Saltmarsh ' Freshmeadow ' when next I meet him. A final rule for memory has already been implied: one should repeal the fact, or the series, or the group of facts to be remembered. This rule is based on the principle underlying association that the frcr^uently occurring experience is likely to be suggested, or remembered; and that it is also, by virtue of mere repetition, likely to be suggestive. However commonplace or naturally uninteresting the scene or the paragraph, let it often enough be repeated in one's experience and one is bound to remember it — perhaps to the exclusion of the vivider landscape or stanza. This is a truth of very great pedagogical importance. We know that naturally interesting and recent and frequent experiences are likely to recur. But the interest — that is, roughly speaking, the pleasantness or unpleasantness, or unusualness — of an exjxrience is, for the most part, beyond our direct control. We cannot at will make our experiences vivid in order to remember them, nor dull their poignancy in order to forget them. And though we are often able to secure the recency of our experience — to refresh our memories and to 'cram' overnight for examinations — yet this sort of memory is notoriously evanescent. In repetition, on the other hand, we have a memory-method which is, in great degree, directly subject to our control and variation and which is also significant and relatiwly permanent in effect. With a sufBcient number of repetitions one may remember, for a while
at least, almost anything; one may supplement associations which have been formed through impressive or through recent experiences; and one may even supplant harmful associations already formed. A child who often enough repeats, from the safe vantage-ground of his father's arms, the experience of stroking Jack, the dog, will in the end exorcise from his mind the memory of Jack's ovcrrough welcome; and anybody may correct the most ingrained misspellings who will often enough copy the misspelled word in its proper form. Ordinary observation, supported by a certain amount of experimental study, suggests that this voluntary repetition of facts to be remembered is more trustworthy when slow than when fast. It is true that swift learning, when successful at all, is more effective than slow learning, in proportion to the time spent on it ; but many series and groups of facts are too large to be learned at all after this fashion, and facts quickly learned — for example, Shakespearian lines and chronological tables ' crammed ' for examination — seem to be forgotten far more quickly than facts more slowly acquired. Doubtless the great advantage of slow learning is that it facilitates what Miss Gamble calls 'good technique' in memorizing; and by this is meant, wisely distributed attention, artificial grouping, and emphasis upon the connection between terms in a series.
Experimental investigation has concerned itself especially with repetition as a factor in memorizing series and has supplied two corollaries to the theorem that repetition strengthens memory. These are : first, that repetition has a diminishing effect : that I learn more in the first few repetitions than in many later ones; second, that repetitions are more effective if distributed than if massed — that it is better, for example,
hours than to repeat it twelve times on a stretch.
We conclude then that, for each one of us, there is good hope of cultivating the memory. By discriminating attention, by careful grouping of the diverse, one may wisely apprehend one's material; and by [)atient repetition one may increase the likelihood of its reappearance. Even the man with the wretched verbal memory should not give over hope of improving it; for an exact verbal memory is a priceless possession. A word may summarize, as no other can, a mass of details or may express a meaning which no other can carry. And a beautiful word-sc([uencc on the li[)s or on the pen of a master of style has an irreplaceable music and charm.
I. Recognition as Personal Attitude
The word ' memory ' is commonly used with two distinct meanings. "I remember" Goethe's "Erlkonig" when I can correctly repeat it; but "I remember" the teacher who set me to learning the poem when I recognize her, twenty years later, an unexpected figure in the Potsdamer Bahnhof. These two experiences, though very often combined, are utterly different and are therefore wisely distinguished by different names. In this book, accordingly, the word ' recognition ' is used to indicate the consciousness of an object as identical with an object of my earlier experience, whereas 'memory' is used of accurate reproductive imagination, the repetition of former consciousness. Memory, in this sense, is very often supplemented by recognition, yet is possible without it. For example, I am remembering if I "see with my mind's eye" a vision of the Dent du Midi, even though I do not at the moment realize tliat this imagined mountain is called "Dent du Midi," or that I have ever before seen it. But I am recognizing when I say to myself, "I saw this mountain on a July day from the INIontreux terrace," or even if I reflect, "I have seen this mountain before, though I don't know where or when." Recognition may accompany perception, and indeed every sort of experience as well as memory. The example just given is of recognition with memory; but
when in the summer of igoi I actually saw the Dent rhi Mi(H, for the second time, I recognized it as the same mountain which I had first seen ten years before — and this was recognition with perception. Recognition is distinguished, also, as more or less complete. When I recognize a figure in a Paris crowd as one I have seen before, but try in vain to recall name or home or other association, this is very incomplete recognition. The recognition is relatively complete if, on the other hand, I recognize the figure as that, for exam])le, of Professor Harold Hoffding; if I recall that I first met him in the World's Fair Building at St. I.ouis in 1904; that he has written a book on psychology, a history of philosophy, and a philosophy of religion; that he has a son w-ho is much concerned in problems of Danish education, and so on.
It is evident that there are indefinitely many grades of completeness of recognition, and it must now be shown that this completeness consists in the supplementation of recognition by associated imagination. Totally incomplete recognition, which occurs seldom (according to some psychologists, never), is that in which one perceives or imagines an object without any associated imagination of former place or circumstance. The recognition is nearly incomplete if there occur only a single supplementary imagination — for example, if the recognition of a face suggests one image only, that of a steamer-deck; it grows fuller if there follow more images — for instance, if the steamer-deck image is succeeded by the verbal image, " Devonian, 1Q02"; it is more nearly complete when there follow — probably after a pause and in a rush — still other images, verbal or concrete, for instance, the images of "Colonel Blake, Civil War veteran, travelling with a ])retty young wife."
useful recognizing that some psychologists have described recognition as any experience supplemented by imagination. This account of recognition is, however, discredited by certain experimental studies. These show at least three types of recognition which would be impossible if the recognition consisted in supplementing imagination pure and simple. There are, first, cases in which imagination follows on the consciousness of an unrecognized object, as when I call an unfamiliar object by a totally incorrect name. Obviously, recognition cannot consist in the image of a word which does not have any connection with the object recognized. Cases occur, in the second place, in which the recognition precedes the supplementary imagination by a marked interval — in which, for example, an odor is recalled as familiar long before the imagination of name or of circumstance. Here, the recognition precedes the supplementary imagination and cannot, therefore, be identical with it. There are finally a few cases on record — too few, however, to be, in themselves, decisive — in which an object has been recognized without the occurrence of any supplemental imagining.' *
Up to this point, recognition has been described and illustrated in a more or less untechnical way. We must now discover and formulate its essential characters; and first of these is the emphasized persistence of fhe self in recognition. When I recognize, I regard my present self as experiencing in the present what I, this same self, experienced in the past. John Stuart Mill dwells on this character of recognition in a well-known passage about memory (by which, as will appear, he means what we are calling recognition).
Recognition as Relational Consciousness 127
"What is memory?" he asks.* "It is not merely having the idea of [a] fact recalled. It is having the idea recalled along with the belief that the fact, which it is idea of, really hai)j)ened . . . and ... to myself. Memory implies an Ego who formerly experienced the facts remembered, and who was the same Ego then as now." The consciousness of myself as ' same ' through changing experience is thus an integral j^art of recognition.
We may next ask: Of what besides my persisting self am I conscious in recognition ? in other words, what is the object of my recognition? Apparently it may be of any tyj)e. I may recognize a person; an external thing or scene; an impersonal rule or law ; or, finally, my own experience as such. More carefully scrutinized, the object of recognition is person, thing, or impersonal fact regarded as identical with the same object experienced in my past. The object of recognition, in a word, is an object related to myself.
The structural analysis of recognition will form the final stage of this description. From percej)tion and imagination, which (it will be remembered) are analyzed into elements mainly sensational, recognition is distinguished by the prominence of elements of a totally different sort, relational elements, as they have been called. The nature of these relational elements has next to be considered.
hold that there are but two classes of elements: sensational elements, the color-qualities, taste-qualities, and the like, and affective elements, the feelings of pleasantness and of unpleasantness.* The element of attention, or clearness, is sometimes named in addition to these.f But many contemporary psychologists, including the writer of this book, are convinced that all these analyses are inadequate; that we have certain experiences which are not completely analyzed, even structurally, when the sensational and the affective elements and the attention, which form part of them, have been enumerated; that there are, in other words, elements of consciousness other than the sensational and affective elements and attention. These neglected elements of consciousness have been named relational, and it is not difficult to discover experiences into which they enter as significant part. When, for example, I try to match one green with another, my consciousness of greenness, of colorless light, of brightness, and of extensity are not the only elements of my consciousness. On the contrary, the consciousness of the likeness or difference of the given green as compared with the standard is the very essence of the experience. Again, when I think of a vibrating string as cause of a sound, the consciousness of causal relation is as distinct a feature of my experience as the sensational consciousness of pitch or of loudness.
But, easy as it is to point out experiences characterized by relational elements, the attempt to enumerate them discloses extraordinary obstacles. They have no special physical stimuli, and they are physiologically conditioned not by any end-organ excitation but by brain-change only — either by
Uk- excitation of the so-called association centres, or by the excitation of transserse fibres, or in both ways.* Un account of this lack of distinctive physical stimuli, the relational elements cannot easily be isolated and varied by experimental devices, since experiment must be applied to physical stimuli and not directly to consciousness itself.f In our study of these relational elements we are in great part, therefore, thrown back upon individual introspection — notoriously untrustworthy and at this point especially difficult. We are thus liable to mistake a relatively simple yet analyzable experi ence for one which is really elemental. For all these reasons it is unwise to attempt a full classification of relationa: elements. The following enumeration is incomplete, and indeed merely tentative. Of the experiences which it names, some, doubtless, are not wholly unanalyzable ; but all are irreducible to merely sensational and affective elements : The experiences of 'one' and of 'many' are peculiarly constant elements of this class, that is, they seem to lie at the base of most relational experiences; and what James calls the 'feelings' ^ of 'and,' and of 'but' — that is, the consciousness of connection and of opposition — and the experiences of 'like' and of 'different,' of 'more' and of 'less,' are certainly relational experiences and are probably also elemental.
Few wide-aw'akc adult experiences arc destitute of these relational elements. Perception and imagination, for examplCj though predominantly sensational, are characterized, as we have seen, by a consciousness of unification (or together-ness) and of separateness.J And whenever, as in the experience
now under discussion, that is. in recognition, I am conscious of time, there the relational consciousness is significant. Psychologists who deny the occurrence of any elemental relational consciousness believe that recognition may be adequately described without recourse to it. When, for example, I recognize a certain picture in the Hague gallery, my consciousness includes, they hold, merely (i) the visual elements involved in my consciousness of the rich brown tints, the high lights, and the contour of the face; (2) the verbal imaginationof the names of picture and of painter — "Homer," by Rembrandt; (3) the organic sensations due to my relaxed attitude as I come upon a well-remembered picture among many unfamiliar ones ; and (4) a feeling of pleasure. But though all these are truly elements in my consciousness of the picture, by themselves they would not constitute recognition. To this belongs a simple, though not an elemental, experience, which may be named the consciousness of familiarity. It is hard to analyze, yet clearly characterized by nonsensational elements other than the affection of pleasantness, and attention. Like some sensational complexes, the consciousness of humidity, for example, it is so intimate a fusion of elements as to have an individuality of its own. But like that, too, it is after all capable of analysis into simpler parts, the relational consciousness of 'same' and of 'past.' In other words, the consciousness of an object as familiar, that is, the recognition of an object, seems to include, when reflected on, the consciousness of sameness with a past thing, and the recognition of an event means the awareness of ' this event identical-with-something-past.' Closely observed, therefore, every experience of familiarity is analyzable into these factors. This does not mean that we necessarily think of the words 'same'
or 'past,' but thai we liavc special sorts of consciousness expressed 1)\- these words. The experience of sameness is relati\el\' simple. The anal\'sis of the consciousness of the j)ast is far more dilTicult. It involves, like all consciousness of temporal relation, a realization of the ' moment,' that is, of the fact which is linked with other facts in two directions. But the 'past' is the irrevocable, unrevivable moment. The experience of the past may, therefore, be roughly described as the consciousness of an irrevocable fact, linked in two directions with other facts.
The study of volition will involve a consideration of another sort of relational consciousness of time, that is, the consciousness of the future.* But the chapter immediately following on this will discuss, instead, those impersonal forms of relational consciousness which are called thought. The results of the present chapter may be recapitulated in the statement that the recognizing self is (i) relationally conscious of (2) itself as persistent and of objects as related to its past. Comparing recognition with perception and imagination we find, therefore, that it differs mainly in two respects from both. It is, first, an ex])licit and emphasized consciousness of myself, and, in particular, of myself as persistent. Every experience, it is true, includes this consciousness of persisting self, but in perception and in imagination the awareness of self is unemphasized and unattended-to, whereas, in recognition, it is the centre and core of the consciousness. Recognition is, in the second place, an experience in which not sensational but relational elements arc predominant.
memory,' which is l)cttcr named false recognition. It has two forms, j)erceptual and imaginative recognizing. An example of the I'lrst is the 'been-here-before' feeling which sometimes overwhelms us when we enter strange places and new scenes. Rossetti has vividly described this experience: —
In the second type of paramnesia one "recognizes," as belonging to one's past, imaginations which correspond with no past occurrence. Many of our dream imaginations and many experiences of the mentally deranged are of this type ; but even commoner illustrations of it are the inaccurate testimony and the fictitious 'recollections' of perfectly honest people. Nicolay and Hay, the biographers of Lincoln, are quoted as saying, from their experience in editing recollections, that "mere memory, unassisted by documentary evidence, is utterly unreliable after a lapse of fifteen years."
THOUGHT : CONCEPTION
The words 'thought' and 'thinking' are often on our lips and are used with many shades of meaning. To begin with : 'thought' is often identified with 'consciousness,' and is thus contrasted with 'matter' or 'extension.' This is the meaning which Descartes gives to the word in his famous proposition : "Cogito ergo sum." Again, 'thinking' is often used to describe all non-perceiving consciousness: "What are you doing in the dark?" some one asks me; "Just thinking," I may answer — and ' thinking ' here means imagining, indulging in revery. The psychologist, however, is wont to use the terms in stricter and narrower fashion and to mean by ' thinking' not consciousness in general, but a form of consciousness to be distinguished as well from imagination as from perception — namely, the consciousness of objects as related to each other. The thinking self is the self (i) relationally conscious (2) of related objects which (3) it knows, reflectively if not immediately, as objects, also, of other selves. We shall consider these characters of thought in a slightly different order; and shall begin by seeking illustrations of the difference] between perception and imagination, on the one hand, and thought, on the other. I see or imagine a strawberry and a tomato; a scaly loljster ; an electric drum which rexolves after I touch a button. But 1 think about tiie likeness of strawberry to tomato ; of the class of Crustacea ; and of the causal
connection between electric contact and mo\ing drum. In my thinking I am, in other words, attentively conscious not of color, sound, or fragrance, nor of happiness or unhappincss, but of likeness, of causal relation, or of logical grouping.
The related objects of thought may be of any sort, personal or impersonal, external or non-external, puljlic or private. I may, for example, compare (and thus think about) selves, about things, about formulas, even about my own experiences. I think about these objects, however, as related, and as related not to me but to each other. Otherwise stated, the relation is impersonal, even when the related objects are personal. Herein thought-objects are sharply distinguished from recognized (or familiar) objects, from the objects of my love, my hate, and my other emotions, and from the objects of my will. Of all these objects I am directly aware as related to myself; whereas, in thinking, I am only vaguely conscious of myself but attentively conscious of the objects, as related.
We have next to notice that thinking is not, like imagination, a 'private' experience. As in the case of perception I am conscious, either immediately (during my thinking) or reflectively (as I look back on my thinking) , that I am sharing the ' experience of other thinking selves.^ * Otherwise stated : thought-relations are public, universal, not peculiarly my own. There is something private and particular about my reveries and my day-dreams, but my thoughts are never regarded as personal property. My castles in Spain are private dwellings, but the great halls of thought swing wide to
every comer. This is most readily illustrated from the more abstract sorts of thinking, and the most striking of all examples are from logic and mathematical science. No man appropriates the multiplication table or the axiom that things equal to the same thing arc equal to each other, or the theorem that the sum of the angles of a triangle equals two right angles, as an ex])erience peculiar to himself.
The character of thought which has still to be emphasized is revealed by a structural analysis. My consciousness of objects as related is distinguished by elemental experiences of a special sort — relational experiences, or feelings, as the preceding chaj^ter has designated them. These feelings of likeness and of difference, of totality, of opposition, are exj)eriences as distinct as the sensations of blue, of noise, of saltness, and the affective feeling of pleasantness. There are no physical stimuli, and no well-established or finely differentiated neural phenomena with which we may coordinate them ; but they are all, none the less, distinct experiences, and not to be resolved into sensational and affective elements. There are as many kinds of thinking as there are impersonal relational experiences, and these forms of thinking are most readily grouped according as their objects are temporally or nontemporally related. Causal thinking, invohing a reference to temporal order, belongs to the first class; comparison, the consciousness of objects as like or dilTerent or equal, is a form of non-temporal thinking, for 2X2 is 4, and white is other tlian black, not now or to-morrow, Init without any reference to time. To discuss in detail all the forms of thought would carry us beyond our limits. We shall, therefore, consider only three: conception, judgment, and reasoning.
Conception is the relational consciousness (reflectively attributed to other selves also) of a group or of an object as member of a group. Conception is, indeed, distinguished from all other kinds of consciousness by its generalized object. I perceive or imagine, for example, my own striped pussy or the pumpkin on the kitchen table, but I conceive the class ' cats,' or 'any pumpkin.' Conceptions of both sorts are the terms, as will appear, of general judgments expressed in such propositions as "cats eat mice," or "pumpkin is for making pies."
The relational experiences especially distinctive of conception are the experiences of generality. These are two (corresponding with the two sorts of object of conception) : the consciousness of class, and the consciousness of 'anyness,' that is, of membership in a class. Thus, my consciousness of the pumpkin includes not only (i) the sensational consciousness, probably indistinct and shifting, of the yellowness, smoothness, and roundness of the pumpkin and (2) the vague relational consciousness of oneness and of distinctness — for if this were all, conception \^'ould not be structurally different from perception and imagination — but also (3) one of the two relational experiences of generality, the consciousness of class or the consciousness of ' any.' Neither of these is a strictly elemental consciousness. The first is the consciousness of the oneness of many similars, and therefore involves at least three elemental experiences. The second is the consciousness of similarity to the many forming a group, and is consequently even more complex. But somewhat as the sensational consciousness of quality, the consciousness of intensity, and that
in a consciousness of generality.
Conception may be described cither in terms of its object or in terms of the elemental kinds of consciousness into which it is structurally analyzable, for the two sorts of description are, roughly speaking, parallel. From the first point of view, conception is classified by reference to the common features of the class which constitutes its object ; according to structural content, conception differs in that the consciousness of generality attaches to one or another of the experiences into which the conception is analyzable. It would be foolish to attempt an exhaustive enumeration; but three important types of conception must be named. These are (i) verbal, the consciousness of a class (or member of a class) whose common character is a name; (2) relational, the consciousness of a class (or of a member of a class) whose common character is a relation — say of order, opposition, or degree ; (3) motor, the consciousness of a class (or member of a class) whose common character consists in this, that each one of the class calls forth a similar bodily reaction. These descriptions are in terms of the object of conception. Described from the standpoint of structural analysis, verbal conception is the i)erception or imagination of a word, supplemented by a feeling of generality ; relational conception is that in which the consciousness either of class or of 'anyness' attaches itself to a j^redominantly relational experience; ynolor conception is conception in which the consciousness of bodily reaction is the significant and characteristic centre to which the consciousness of 'class' or of 'any' attaches.
consist mainly of verbal imagination augmented by a feeling of generality. Yet the role of verbal imagination in thinking has probably been overemphasized ; and abstract conception is doubtless more often relational than purely verbal. When, for example, in studying logic or theoretical natural science, I conceive order, series, function, force, or causality, my consciousness is best described as a relational experience accompanied by the consciousness (also relational) of generality; and the object of my thought is rather a relation than a word.
Concrete conception is in great part of the motor type. The generalized feature of my 'hat,' for example, is not the material, or color, or form, because no one of these is common to the innumerable, widely different objects known as hats. Between the minister's silk hat and his wife's picture-hat with the ostrich feather there is, in fact, little in common except the characteristic motor reaction called forth by each. The hat is thus the 'to-be-put-on-the-head,' and this imagination of bodily reaction is probably the part of my consciousness of 'hat' which is accompanied by the experience of generality and followed by a series of images, — of mortar-board, cardinal's hat, and peasant's cap, — very different objects, similar in this one respect, that they are things to be put on the head. In the same way, foods differ in every conceivable particular of color, form, and consistency, but agree in calling forth a common system of bodily movements. The generalized feature of the object ' food ' is thus the fact that it is the ' to-beeaten.' In the same way, the pen is the ' to-be-written-with,' the flower is the ' to-be-smelled' or 'to-bc-picked,' the chair is the ' to-be-sat-down-in.' ^
conception belonging to a given moment is associative of a scries of images of closely resembling objects/ In other words, a conception forms the starting-point for a scries of partial associations. This mark of conception, it will be observed, is not a constituent feature but a function of it — not a part of it, but a result of it, as it were. There can be no doubt that a conception is, as a matter of fact, followed by a series, longer or shorter, of images of objects said to belong to a class. The conception of 'boat,' for example, suggests a panoramic series of images of canoes, sloops, fishing schooners, and warships; and the conception of 'bag' is followed by a rapidly shifting procession of images of travelling bag, shoe bag, ragbag, knitting bag. This function of suggesting the images of similar objects is often expressed by saying that a conception, or generalization, "represents" or "stands for" a group of similar objects. Herein it is sharply contrasted with ungcneralizcd perception or imagination. My perception of one particular kind of opal ring is likely to associate an imagination of the odd little shop in "la rue de la Grosse Horloge," where I bought the ring, and this in turn may be followed by the image of the friend who incited me to buy it and by the memory of her disquisition on ancient gems. The images succeeding on perception or imagination may thus be of objects very different from each other and from the initiating experience. In the case of conception it is otherwise. The conception 'ring,' for example, associates a series of images of rings, each resembling all the others in the possession of certain common qualities, and the conception 'theorem' is followed by the consciousness of ])ropositions and of figures from the dilTerent books of Euclid, each more or less similar to the rest.
b. The Uses and Dangers of Conccpiion
There is no more insistent mental impulse and no more persistent mental habit than that of framing conceptions. Once I have learned to generalize I am eager to refer every new object, event, or situation to its class, and to regard it as 'any' or as ' one of a group ' and not merely as ' this.' I see an oddly shaped piece of metal; it is an irregular, oblong object, silvery, carven, hollow : I am uneasy until I -classify it as a vase or as a tea-caddy or as a paper-weight, that is, until I group it with other objects similar to it in few or in many characters. Or I find, as I walk for the first time in the Maine woods, a flower which I never have seen, and I do not rest until I group it with the orchids, regarding it not as a single individual but as one of a class.
This ineradicable tendency has its justification, and — in a way — its explanation, in the significance of conception in the mental life. It is true that by conceiving I in no wise enlarge my experience — that is, I learn nothing in the technical sense of the word ' learn ' ; but, on the other hand, I wisely sort out and distribute and preserve the results of past experience. It will, however, appear in the next chapter that the general judgment (which is merely the conception supplemented by a feeling of wholeness and analyzed by discriminating attention) is an important constituent of reasoning ; * and in this way conception, like memory, though itself a preserving function, lays the foundation for creative experience, for acquisition. It will be shown, also, in our study of will, how conception
simplifies choice by helping us to subordinate j)articular possibilities of thought or action* to classes which \vi' ha\e earlier chosen or rejected. In brief, generalization groups objects of our consciousness, and the result of this grouping is that a single pulse of attention covers a mass of phenomena that must otherwise be dealt with singly, at great loss of time, or utterly neglected.
It will later be shown that conception has a social as well as a mainly individual value in that it facilitates intercourse between conscious beings by making possible conventional language.f Conception aids intercourse also in an even more fundamental way. We communicate with people the more readily because we and they form conceptions. For in conceiving we lay stress on common experiences and we abstract from that which is peculiar to ourselves. Thus, we may talk or write to people who have met few or none of the particular objects of our acquaintance precisely because we have common conceptions; because, for e.\amj)le, we mutually know 'friends' and 'foods' and 'amusements,' though we have no common friends, and live on different fare, and amuse ourselves in very different ways.
It is time to turn from this enumeration of the advantages to a consideration of the dangers of conception. Conception is, as has appeared, a form of generalization, and may therefore menace the life of imagination, of reasoning, and of emotion. We are best fitted, at our present stage of progress, to understand the first of these perils. The fundamental excellencies of imagination are vividness and accuracy of detail. Conception, on the other hand, implies indistinctness and vagueness
of sensational detail. My conccj^tion of andirons may be, to be sure, an imagination (supplemcnlcd by a feeling of generality) of andirons; but the sensational experiences of color, of shape, and of surface, are far less vivid and detailed than in concrete imagining. Indeed, if I were vividly imagining the andirons, I should be absorbed in this particular experience; it would no longer 'stand for,' or associate, a lot of similar images ; it would be a ' this' not an ' any.' Evidently, therefore, one ne\'er forms a conception save at the expense of one's imagination; and it follows that one should never generalize when sensational richness is one's chief concern. Obviously, also, conception is peculiarly opposed to creative imagining, the consciousness of the novel, for to conceive is precisely to ignore what is new, to seize on every novel object, scene, or event, and triumphantly to shut' it in with its predecessors in a pigeon-hole already labelled. It is, of course, true that conception may effectively work over the products of creative imagination, but too exclusive occupation with the general leaves no scope for originality or initiative. For a similar reason, conception imperils emotion and will. These, as will later appear, are intensely individualizing experiences, whereas conception, ignoring differences, reduces people and objects to groups and to classes. There is, thus, a double reason why the artist should eschew generalizations. For the work of art should be an embodiment of the imagination of its maker and an incitement to the aesthetic emotion of the observer; and both imagination and emotion are particularizing experiences which have no concern with the general as such.
generalize where we ought to cherish the vi\i(l and the indivichial, yet our h'xes are chaos unless they are ordered by the awareness of rule and group. Without encroaching on the province of imagination we may wisely, therefore, train oursehes to frame useful conceptions. And such training will he gained both b}- attention to similarities of appearance, behavior, and relation, and by the attempt to follow general reasonings as embodied in scientific and philosophical works.
Judgment 145
example, I look oil" at a gray church spire, half a mile below me, and have a consciousness of grayness, form, roughness, oneness, and limitedness. I do not reflect upon this object nor analyze it ; and no one part of it — grayness or tapering height — impresses me more than another. So far, then, my experience is mere perception. But now, for some reason, the grayness of the spire draws my attention ; I lay little stress on its form, but I am interested in its color, — in other words, I have an 'abstract notion' of the color. Finally, however, I am conscious of the grajness as a part of the spire, as belonging to it, as forming with its shape and other features one whole; and now for the first time I am judging, conscious of a complex as a whole inclusive of an emphasized part. Perception and perceptual judgment alike are distinguished, first, from abstraction by their complexity, and second, from the total sensational complex by their limitedness. But judgment is distinguished from i)ercc])tion by the added feeling of wholeness, and by the invariable emphasis of some part within its total or of some excluded factor. The three sorts of experience— perception, abstraction, perce])tual judgment — may be represented in words, by the expressions: "I am conscious of this gray spire," " . . . of grayness," " . . . that this spire is gray." The propositional form of the last clause em])hasizes both the totality of the object of the judgment and the emphasized part of it. These are examples of particular judgments, A similar general judgment would be expressed in the words, "I am conscious that Gothic spires are gray."
according as they start from perception (or from imagination) or else from conception. Judgments are grouped, in the second place, as (2) positive or negative, according as an emphasized factor is included or excluded from the object of the judgment — that is, from the whole of which, in judging, one is conscious. Judgments, finally (3), may be classified from the manner of their formation, as analytic or synthetic, that is, as judgments of reflection or of discovery. An analytic judgment is the result of attention to a whole (external thing, or self, or my own experience). For example, I have seen shadows on the snow a hundred times, but at last I emphasize, by attention, the distinctly blue color of the shadows cast by tree trunks; and then for the first time I make the judgment expressed in the words, " the shadows are blue." I am then definitely conscious of the whole "blue shadows," within which I emphasize the character of blueness. I may make, in similar circumstances, a negative analytic judgment if I am conscious that "the shadows arc not gray." In this case the 'judgment' is rather to be described as complex of succeeding imagination upon persisting perception (or upon imagination) than as simple perception or imagination. For example, this experience of being conscious that "the shadows are not gray" is a succession of the imagination of gray shadows upon the perception of blue ones. The feeling of wholeness attaches to the perception of blue shadows; but the emphasis of attention falls also on the excluded character, the grayncss.
A synthetic judgment arises through the successive consciousness of different objects. In the positive synthetic judgments the two objects are then regarded as parts of one whole. Thus, on the perception of a toad c^uietly sunning
himself follows mv perception of liis mouth opcnint^ in enj^ulf a lly. The eluiraeter of eatinj; Hies forms, henceforth, a factor of the whole, 'toad eating llies,' which is the oljject of my judgment. In this case (of synthetic judgment), though the judgment is reached by a sequence of perception on ])erception, the judgment itself is complex perception or imagination (with emphasized part), characterized by feeling of wholeness. It should be noted that the object of a judgment may conceivably include more than one emphasized part. Since, however, our attention is very limited, it is probable that the greater number of judgments include, psychologically as well as logically, but a single predicate. The judgment, for example, "paramecia are unicellular and have but one form of reaction," though expressed in a single proposition, is, for most of us, two judgments, in which the feeling of wholeness attaches successively to the consciousness of the complex objects, 'paramecia-unicellular' and ' paramecia-reacting-inone-way.'
One final distinction must be noted. Negative judgments are always analytic, for tliey can be framed only on the basis of such experience as makes a judgment analytic. T can attribute a character to an object, though I have never before been conscious of the two together — for example, I can make the synthetic positive judgment, "some water-lilies are pink"; but I cannot exclude from an oljject anything which 1 do not first imagine as belonging to it. Thus, the judgment, "these water-lilies are not white," involves an earlier percept or image of water-lilies as white; and the judgment, " this soup is not hot," implies that soup should be hot, that is, it implies a former acquaintance with hot soup. These are, therefore, analytic judgments.
a. Tlie Nature and Classes of Reasoning
Judgment is best known in the form of reasoning. We seldom reflect upon the single judgment, the mere consciousness of discriminated wholeness in our immediate perception and imagination, but we notice the continuous judging which we call reasoning. A reasoning, or a demonstration, is a succession of judgments leading to a new judgment. It has two main forms — • deductive reasoning, in which the concluding judgment is narrower in scope than some one of the preceding judgments, and inductive reasoning, in which the conclusion is wider than any preceding judgment. These distinctions must be illustrated and elaborated.
The objects of the succeeding judgments of deductive reasoning are related in the following way: each of the partial objects forming the total object of the conclusion, or final judgment, has been combined (as object of a preceding judgment) with another partial object, the ' middle term ' ; and this middle term docs not form an emphasized part of the object of the conclusion. The objects of these succeeding judgments may be symbolized thus : xy, yz, xz, where y stands for the suppressed middle term. In more concrete fashion, this description of deductive reasoning is illustrated by any actual instance. Suppose, for example, the successive judgments expressed in the following propositions: —
Here the first judgment is the consciousness of the bell, with emphasis on the excluded character of ringing. The second judgment is an accentuation of still another character of the bell — the fact of its being an electric bell, and consists in the consciousness of the bell as a whole, with special stress on the fact of its electric connections. In the third judgment most characters of the bell are unattended to, but the consciousness of it as electric is still emphasized and is supplemented by a new consciousness, that of connection with renewed batteries. Finally, in the conclusion, the character of the bell as itself electric is relatively unaccented, but the two characters successively connected with this, (i) that of the bell as ringing (or not ringing) and (2) that of the bell as connected with a renewed battery arc realized as emphasized parts of the whole, 'table bell which rings because connected with renewed batteries.' Thus, the concluding judgment is the realized connection of the terms of two preceding judgments; each of these terms was previously connected with a third term, now unemphasizcd ; and the whole experience is properly called ' deductive reasoning ' or ' mediate judgment.'
Inductive reasoning is less complex. A series of parallel, particular judgments is followed by a judgment, general or particular, more inclusive than any of the preceding judgments. From several observations, for example, of the fact that sal ammoniac added to the batteries makes the bell ring, I formulate the general judgment expressed in the proposition, "all electric bells ring when the batteries are renewed." Such inductive reasoning is thus expressed in a syllogism of the following sort : —
All electric bells ring when sal ammoniac is added.
It is clear that induction is a normal precursor and preliminary to deductive reasoning. For example, the conclusion of this inductive syllogism about electric bells forms part of the deductive reasoning about the table bell. All scientific reasoning is, in truth, a combination of induction with deduction — a series of particular judgments leading to general conclusions followed by the application of these conclusions to still other particulars. The law of the conservation of energy, for example, was formulated as a result of successive judgments, based on observation. The repeated observations of Carnot, Joule, Mayer, and Helmholtz, that mechanical energy is convertible into an equal amount of heat led to the formulation of the general principle that "to create or annihilate energy is impossible and that all material phenomena consist in transformations of energy." The law% once formulated through induction, was applied to energy of all sorts — of light, of electricity, of magnetism; and again these deductions have been inductively established. Thus, induction and deduction supplement each other in all effective scientific procedure. It must be noted, however, that deductive reasoning is not universally based on induction. Instead, it may be based upon judgment immediately known as universal. An example is expressed in the following syllogism : —
Therefore A and B are equal.
Here the second judgment is perfectly general, or universal, but its universality is not derived from the enumeration of many instances of equal alternate-internal angles.
Reasoning, whether deductive or inductive, may consist of varying combinations of many sorts of judgment. The judgments which it includes may be positive or negative, particular or general, analytic or synthetic. In the example of page 148, for instance, the first judgment is negative, the others positive; the first, second, and last are particular judgments referring to my own tal)le bell, Imt tlie third is a general judgment, the consciousness of an important character, connection with renewed batteries, of the whole class of ringing electric bells. The final distinction, that between analytic and synthetic judgments, since it concerns only the manner of formation, not the character of the finished judgment, is not readily expressible in words. It is, however, probable that the first and fourth of these judgments are analytic, and that the third is synthetic. The second judgment may be either analytic or synthetic. It is the business of formal logic to study separately these different forms of reasoning in order to distinguish them as valid or as in\alid. Thus, the logician teaches that reasoning is illicit if it is made uj) entirely of negative judgments, or if the conclusion is wider in sco])e than the premises taken together. Psychology, on the other hand, studies actual cases of reasoning irrespective of their validity or invalidity, taking account |)rimarily of the way in which people do reason, not of the way in which they should reason.
But though the psychologist may concern himself with all sorts of reasoning, it will be convenient to select for discussion the especially effective type of deductive reasoning — founded often on induction — which may be known as analyticsynthetic reasoning. It consists of the following order of judgments: there is, first, an analytic judgment in which some one feature of a whole object is singled out and brought to the foreground of attention ; second, a synthetic judgment whose object is the emphasized part of the first judgment's object combined with some new character; and, finally, a judgment whose object is the originally unanalyzed whole, supplemented by this new character. Analytic-synthetic reasoning may thus be described in the words which James applies to judgment in general, as the 'substitution of parts and their implications or consequences for wholes.' One concerns oneself, for example, with the question of the restriction of the power of the British House of Lords. One's consciousness of the House of Lords is highly complex and very vague : it includes visual imaginings of hall and of figures, many verbal images, and relational consciousness — in particular the experience of wholeness. If any conclusion is to be reached, it must be by the emphasis of some one feature of that complex object, the House of Lords — the fact, let us say, that it is a hereditary house. At once the simpler consciousness of ' hereditary house ' suggests (as the consciousness of the more complex object had failed to suggest) that a hereditary body under constitutional government should not interfere with legislation. This character supplements the initial object of judgment, the British House of Lords, and is realized as forming with it a whole. We have, therefore, as expression of this reasoning, the syllogism : —
TJic Uses and Dangers of Reasoning 153
The British House of Lords is a hereditary house; Hereditary bodies should not interfere with legislation; The British House of Lords should not interfere with legislation.
A final remark must be made. It must expressly be noted that a given result may often be reached without reasoning as well as through reasoning. The consciousness of a given situation may be followed immediately, without intervening judgments, by a judgment similar to that to which one might have reasoned. The perception that my bell does not ring might, for example, be followed immediately, without intervening analysis, by the consciousness of adding sal ammoniac to the battery. This would be a case of associated imagination and would be explained through the fact that I had previously seen a broken bell rei)aired after this fashion. Cases of supposed reasoning, for example of animal reasoning, are often immediate associative imagining, without the analysis and the mediate judgments involved in reasoning. The next section will compare these two sorts of mental procedure.
The most efficient form of reasoning is the combination of analytic judgments of reflection with synthetic judgments of discovery. Reasoning of this sort is an important kind of self-development, or learning, a means of acquiring new outlooks, new points of view, new bases for action. Analytic-synthetic reasoning attains these ends by means of the analysis involved in the first judgment. For this judgment, since it is analytic, emphasizes a quality or an attribute within a whole object or situation^ and because this discriminated [)art is
less complex than the total in which it belongs it has fewer possible consequences; and because it has these definite consequences, the analytic judgment is likelier than a more complex experience to form the nucleus of a second judgment. When, for example, I judge that a certain mosslike substance is animal, not vegetable, — that is, when I emj)hasize its animal characters — I readily reach conclusions impossible by mere observation of it as a whole. All this is clearly taught by James.* " Whereas the merely empirical thinker," he says, "stares at a fact in its entirety and remains helpless or gets 'stuck' if it suggests no concomitant or similar, the [analytic] reasoner breaks it up and notices some one of its separate attributes. This attribute has . . . consequences which the fact until then was not known to have."
This enumeration of the uses of analytic-synthetic reasoning will be checked by a very natural question. It has been pointed out that this sort of reasoning is not the only method, though the usual one, of enabling us to reach new results. For it is always possible that immediate judgment may replace even analytic reasoning in any given case. One man may gain by a flash of intuition the same result which another attains only by the closest reasoning; and the bare result is as valuable in the one case as in the other. But granting that the mediate method of analytic reasoning is not the only way of attaining the adequate solution, there still remain several unassailable advantages with the analytic reasoner. His results, in the first place, are readily repeated. Intuitions, that is, immediate judgments or mere associations, occur we know not how; and we cannot reproduce them at will. The result which a man has reached by an unexplained * Op. cit.. Vol. II., p. 330.
association, once forgotten, is beyond his voluntary control. On the other hand, he can repeat at will the reasoning founded on close analysis. A student has forgotten, let us say, the accusative singular of the Greek word, iXirk. He remembers, however, the reasoning process by which lie first fixed in his mind the fact that third declension nouns in -i?, when accented on the last syllable, have the lengthened accusative, to avoid the abrupt stop. Thus the accusative eXiriSa, forgotten in itself, is remembered as one link in a chain of reasoning. In the same way, one can repeat a geometrical demonstration, though one has forgotten it, by beginning with the close analysis of the figure; one can recover the lost date, by reasoning from some fact associated with it, by arguing, for example, that, a statesman who smoked could not have lived before the reign of Queen Elizabeth. It behooves, therefore, even the j)erson of quick intuition and of ready memory to train his reasoning power. The (lash of inspiration may be more brilliant, but is surely far less steady, than the light of reason. The Aladdin role in the mental life is no sustained part; the genius which appears at one's first bidding may well forbear to come at a second summons. In plain English, the power to analyze and to reason is relaliw'ly stable, whereas unreasoned association is capricious and untrustworthy. It is, therefore, the part of wisdom to secure a reasoned theology or scientific system or practical philosophy, precisely because one thus has the chance to review and to recall it.
This suggests another advantage of reasoning over immediate association: the oj)portunity which it olTers to the candid person to revise and to amend his results. The most dogmatic and unyielding of individuals is the man who has
jumped at his conclusions. He is naturally tenacious of them, because he has no idea how he came by them and no hope of gaining any others if he lets them go. So the most ardent sectarian is the one who doesn't know the raison d'etre of his own sect, and the most zealous political partisan can give you no reason for his vote beyond the utterance of a talismanic name or symbol. It would be too much, of course, to claim that every reasoning person is open-minded ; but it is quite fair to say that only persons who reason are open-minded. For nobody can reverse his decision who cannot retrace the path of deliberate reasoning which has led up to it.
So far, only the mainly individual advantages of reasoning have been considered. Reasoning has, none the less, a distinctly social value. For the reasoner has at least a fighting chance of sharing his results with other people's. The lucky man who guesses correctly may be brilliant and inspiring, but he cannot well be convincing. He may be absolutely certain that prohibition does not prohibit, or that Sophocles is greater than Aeschylus, or that Hegelianism is absurd; he can even temporarily impose his enthusiastic beliefs on other people, but he cannot work permanent change in their intellectual convictions. We are constantly hearing that argument is futile, and yet there seems no other way of effectively sharing one's conclusions.
It would, however, be unwise to conclude that the results of reasoning are inevitably good. On the contrary, there is always danger lest deductive reasoning be trivial, and lest inductive reasoning be misleading. Deductive reasoning, in the first place, is a waste of time if it is concerned with unimportant matters which are as well turned over to the swifter process of associative imagination; and deductive
reasoning is deadening and dulling when it chokes the spontaneity of imagination. There is no more tiresome human being than the man who insists on arguing every unimportant detail. Even greater peril attends the abuse of inductive reasoning — namely, incomplete induction based on scanty and overhasty observation. General conclusions, inadequately established yet obstinately cherished, are terrible barriers in the way of progress. Indeed, strictly speaking, no absolute certainty attaches to a general proposition based on an induction. As Hume says, "experience can be allowed to give direct and certain information of those ])rccise objects only . . . which fell under its own cognizance;" and it is very rarely possible to examine directly all instances referred to in an inductively grounded universal judgment. One cannot, for example, measure the results of all transformations of energy; and one cannot observe that every particle of matter in the universe attracts every other. The highest degree of probability attaches to the great inductions of science; and there is undoubted utility in inductions based on fewer observations, provided such inductions are used purely as working hypotheses to be thrown aside when found to conflict with fresh observations. But there is absolutely no excuse for the hasty induction except as startingj)oint for further investigation. The progress of science has been constantly obstructed by this over-tenacious clinging to the results of incomplete inductions — to the corj)uscular theory of light, for example, or to catastrophism as explanation of the extinction of prehistoric forms of life. Hasty inductions about peoj)le and
nations arc especially unsafe, because human beings, as com])ar(.'(l with ])hysical phenomena, are peculiarly irregular in behavior. And yet books about America and France and Turkey are still written as the outcome of three-months' observations and we are still taught that all Frenchmen are insincere, that all Americans are materialistic, and that all Germans arc musical. To be sure, many observations contradict all these conclusions, but the motto of the inveterate generalizer has been well stated in the words, " If the facts don't correspond with my theory, so much the worse for the facts." The truth is that there should be no exception to the rule: inadequate inductions are never to be made except as basis for necessary decision or for further scientific testing.
in Particular of Reasoning
We reminded ourselves at the outset of our study that physiological and psychical phenomena seem to correspond closely, and that the human body is the most constant of the objects of our perception. Accordingly we undertook to classify and, as far as possible, to explain the facts of our consciousness by constant reference to regularly preceding, accompanying, and following bodily processes. We have now to carry out this part of our programme with reference to thought, and in particular with reference to reasoning. So far as brain processes are concerned, little need be added to what has been said about the brain conditions of relational experience.* More obviously significant than these hypothesized brain conditions are the observable bodily reactions which accompany thinking. They vary, of course,
Bodily Accompaniments of Reasoning 159
with the different forms of thought, but we should notice especially first, the habitual reactions called forth by conceptions (as by perceptions) ; * and second, the delayed and often hesitating reactions which accompany reasoning. The habitual movements corresponding to our concei)tions have been discussed in the preceding chapter. f The hesitating reactions of reasoning demand further comment. As contrasted with the relatively immediate reactions which accom[)any our perceiving, our imagining, and even certain forms of thinking, — swift comparisons, for example, — the outward behavior in reasoning is markedly slow. Let us suppose, for example, that a boy jumps into his dory and l)ushes off for a row. To place the oars in the rowlocks is a reaction, coordinated through experience, which follows at once at sight of the oars. But suppose that the oars have been left behind, and that he reasons out, somewhat as follows, the way of getting back to shore : —
The seat will serve as oar.
The bodily reactions which accompany this reasoning do not follow instantaneously on his consciousness that the oars are gone. There is perhajjs a moment, while he is thinking of the forgotten oars, when he makes no movement; then his eyes wander from one end to the other of the boat; then he grasps the board in the bottom of the boat and tries in vain to pry it up; finally he loosens the seat and begins awkwardly
to paddle with it. Such a scries of bodily motions is sharply contrasted on the one hand with the instantaneous and coordinated reaction which would have followed on the perception of the oars, and on the other hand with the equally immediate but uncoordinated, chaotic, excited reactions which would have accompanied a mainly emotional (that is, frightened), unreasoning consciousness that the oars were gone.* In this latter case there would have been no pause, no regular movements of eyes and hands, but rather excited, interrupted movements — shrieks, excited waving of the hands, jumping from one end to another of the boat. Conceivably, one of these excited movements might have turned out to be successful in getting the boat to shore, — • for instance, he might accidentally have seized the boat-hook, have swept it back and forth in the water, and so have brought himself toward land, — Ijut this success would have been neither a result nor a proof of his having reasoned out the way of reaching the shore. It would have been the accidental outcome of the random movements that accompany emotional consciousness.
The obviously hesitating and delayed character of reasoning reactions has furnished to comparative psychologists an important objective criterion of the occurrence of reasoning in young children and in animals.^ Untechnical observers incorrectly suppose that the spontaneous, untaught performance of any successful action, which is not an instinctive response, is in itself a proof of reasoning. The objection to this conclusion lies in the fact that the animal may have performed the supposedly reasoned act either
through accidental immediate reaction or else through memory, not through reasoning. The dog who brings the sponge has, presumably, often seen the sponge both in the boat and in the shed to which he runs to fetch it; immediate association without reasoning sufTices to explain his action. And the dog who opens the gate may have opened it first by an accidental mo\'ement, and later by memory of that movement.
To test this last hypothesis, many psychologists have experimented in the following fashion: The dog, cat, bird, monkey, or other animal on whom the experiment has been made, has been conhncd, when more or less hungry, in a cage, or large box; food has been placed in sight of him, but outside his enclosure; and this has been so arranged that the animal may escape by "manipulating some simple mechanism" through movements which he is perfectly capable of making — for example, by "pulling down a loop of wire, depressing a lever, or turning a button." The animals have invariably responded by instinctive, excited, random movements of all sorts — by leaping, biting, clawing, trying to sc^ueeze through holes. In other words, they have responded with the immediate, random, excess movements characteristic of the affective and excited consciousness, not with the delayed and relatively calm responses of the reasoning mind. In the course of these excited movements they have, it is true, chanced, ordinarily, on the successful reaction which has released them from confinement. But such a reaction is certainly no proof of reasoning. For not only is it made in the course of the animal's chaotic, random movements; it is often, though not always, an action ne\-er repeated. To quote Professor Thorndike: "In the case of some dilTicult associations," t]io animals "would happen to do the thing six or seven
times, but after long j)crio(ls of j)romiscuoiis scrabbling, and then forever after would fail to do it." This observation has been substantiated by other experimenters, and shows abundantly that in these cases the successful acts are performed accidentally, and not through reasoning. For what one has reasoned out, one remembers: in Thorndike's words: "If they had acted from inference in any case, they ought not to have failed in the seventh or eighth trial. What had been inferred six times should have been inferred the seventh." *
It is fair to conclude, on the basis of this evidence, that there is so far no proof of the occurrence of animal reasoning. None the less, many animals possess an alert and many-sided intelligence ; for the immediately associated imagination may, as has been pointed out, lead to the same result, in action, as the reasoned conclusion. In questioning the ability of higher animals to reason, we are not, therefore, questioning their capacity to act effectively, or their possession of rich percepts and of swift-coming images.
IV. Thought and Language
A brief consideration of the nature and the function of language is rightly included in this chapter ; for conventional language is, in a way, both effect and condition of the two significant factors in thought : generalization and abstraction. Generalization in its two forms, conception and general judgment, has already been considered. By abstraction ^ is meant attention, with emphasis upon the excluding aspect of attention. For in attending to anything one abstracts from the unattended-to part of the total object of experience; and in
this sense the attended-to is the aljstract (more literally, the abstracted), and attention is abstraction. Language, in its widest sense, is an aggregate of bodily reactions (or results of bodily reaction) — in particular, an aggregate of articulate sounds or of gestures — by which conscious beings communicate with each other/ Of language, thus defmed, there are two forms ; and the first of these is natural language in which the communicated sounds and gestures are mere immediate and instinctive reactions, imitative and interjectional in their origin.* The different barks by which a dog signals to another, 'food,' 'danger,' 'friend,' are instances of this so-called 'natural language.' Obviously it is highly significant in the development of social relations, emotional and purposive, of conscious beings with each other. Certainly, however, it need not inx'olve thought of any sort. And — what seems at first sight more curious — natural language can be understood by such animals only as are of common species and environment. Mr. Garner, for example, who spent many months in learning the 'language' of monkeys, in one of our Zoos, was disappointed in the hope of gaining thereby an understanding of the cries and calls of monkeys in the African jungles. This is because the natural sounds and movements are so variously modified by differences in bodily structure and in environment.
With conventional language the case is different. The word, just because it is not, in its present form, the instinctive expression of any feeling, or the copy of any natural sound or shape, may be learned by all individuals who are capable of apprehending and {)roducing it. A word is, in fact, an
artificial sign realized as representative of something besides itself. The aljility to know a given sound or gesture as a sign demands first, abstraction, that is, exclusive attention to the representative character as distinguished from all the more naturally interesting sense-qualities of the sound or the gesture; and second, generalization, that is, the grouping together of a lot of sensibly dissimilar sounds and motions by virtue of this likeness of function. Animals seem to lack this ability to abstract and generalize the sign-character, that is, to learn that phenomena so different as w^ords pronounced, barks, and paws crossed are alike in the character of standing-for-something.^ It follows that animals make and understand sounds and movements which actually serve as signs, but that they do not know sounds and movements as belonging together to the class ' signs.' Thus, I may teach my dog. Doc, that a sharp bark will secure release from confinement, or that crossing his paws will bring him food, and I may even teach him to distinguish certain words, as 'food' and 'water,' and to associate them with the appropriate objects. But he knows these words and barks and postures, each for each, as associated with a particular object, not as possessed of the general character of standing-for-something else.*
It has thus appeared that abstraction and generalization are essential to the formation of conventional language; and it must now be shown that abstraction and generalization (the important factors of thought) are greatly facilitated by conventional language. Conventional language aids abstraction or attention, because the reference of any word may be so limited. I may, it is true, abstract without the use of words — for example, in looking at a marble, I may attend
to its sha[)c, abstracting from its color; but I cannot help seeing the color with llie shape, and therefore the use of the word 'spherical,' referring as it does to form exclusively, assists abstraction. In other words, verbal imagination lacks the distracting comj)lexity of concrete imagination.
Language must, in the second place, aid generalization, since every word of a conventional language (exclusi\e of its proper nouns and its interjections) is a general term — that is, the consciousness of a word may suggest any one of a whole group of objects. Of course a concrete image sometimes serves this same purpose of suggesting a group of similar objects, but the very poverty and simplicity of the word specially fits it for this general reference. The image, for example, of my special lynx muff will be followed by the consciousness of places where I have carried it, railroad stations in which I have left it, and the like, whereas the perception or imagination of the word 'mulT,' free of vivid, particular associations, more readily recalls the whole class of muffs. Thus, words serve often as a sort of tag, or sign, for the class once formed, an artificial help toward distinguishing and remembering it.
But while it is thus abundantly evident that thought and language are closely related, we must guard ourselves against two psychologically untenable views: first, the supposition that words invariably suggest classes of objects, and second, the belief that every general term implies a corresponding conception. As to the first point: experience shows that though a word is always a general term in the sense that it may suggest a class of objects, yet it actually often suggests a single particular object or relation. The word 'wave,' for example, in the lines, "The breaking waves dashed high, on a stern and rockbound coast," may, of course, suggest the
class 'waves' and may be followed by a series of resembling images — say of waves of the sea and of air-vibrations. More likel}-, however, the word at once suggests a concrete object or scene ; and one has a vision of a headland of the rocky New England coast. Indeed, the aim of poet and of narrator is precisely to hold words to the function of suggesting particular scenes and emotions and to prevent their use as representative of the class or group. Thus the potential general term may remain a mere verbal image. In the second place, a word may be a general term and perform its function of suggesting similars while yet it corresponds to no conception or general notion. This is the case wherever the word-consciousness is unaccompanied by an awareness of generality. I may read the word ' chest,' for instance, and it may suggest to me a series of boxes of different shapes and sizes, and yet I may not be conscious of any generality. In this case, though the spoken or written word 'chest' may be called a 'general term,' the verbal imagination of 'chest' is not, according to our doctrine, a conception.
It is thus evident that words need not correspond directly with conceptions. It is equally important to realize that conception and, indeed, all forms of thinking, are possible without language." It is true that most of us think in words. We find it difficult or impossible to carry out a long train of reasoning without formulating in words the different stages of it ; and even when we reason silently, we are likely to discover ourselves imagining sub silentio the words of our argument. In conception, also, the verbal imagination often forms the centre of our experience ; so that, for instance, the conception 'truth' almost always includes a verbal image. Etymologists, indeed, argue that the absence from a given language of a
particular sort of words or signs is probably indication of a lack of the corresponding conceptions. Savages unpossessed of a system of numerals count up to five or six only, and ])crform no intricate arithmetical operations; and from the j)aucity of color-terms in Homeric Greek it is argued, not unreasonably (though not decisively), that the Hellenes of this period discriminated few colors. But all this simply shows that conventional language facilitates and establishes thought, and that the two develop by a sort of mutual interrelation. To insist, as Max Muller insists, that thought is impossible without language, is to overlook the outcome of much introspection and to misapprehend the nature as well of thought as of language. Conventional language is, as has been said, a system of signs, composed of certain images, usually auditory, motor, or visual. Thinking, on the other hand, necessarily includes a consciousness of impersonal relations. It is absurd to assert that the experience of objects as related is absolutely dependent on one's possession of any specific set of images, ,
Certain experiences of the deaf and dumb furnish interesting testimony on exactly this point. DT.strella, an educated deaf-mute, has given a detailed account of his moral and theological reasoning in the very early years of his neglected childhood.* He had never attended school, knew nothing of the conventional gesture-language, and i)ossessed, in fact, only a few rude signs, none of them standing for abstract ideas. Yet, during this time, he not only gained a belief that the moon is a person, — a conclusion carefully reasoned from facts of the moon's motion and regular appearance, — but, by meditating on other nature-facts, he found for himself a god, * James, Philosophical Rei'iew, Vol. I., pp. 613 seq.
a Strong Man behind the hills, who threw the sun up into the sky as bo)s throw fireballs, who puffed the clouds from his pipe, and who showed his passion by sending forth the wind. Mr. Ballard, another deaf-mute, describes a parallel experience,* his meditation " some two or three years before . . . initiation into the rudiments of written language," on "the question, How came the world into being?" Testimony of this sort, though of course it may be criticised as involving the memory of long-past experiences, confirms the antecedent probability that thinking may be carried on in any terms — concrete as well as verbal. Whenever one is conscious of a group, or of a member of a group, then one is conceiving. The conception may include a verbal image, but need not. Whenever one is conscious of the wholeness of a complex, with emphasized part, then one is judging. The judgment often includes an imaged proposition, but does not necessarily contain it. Whenever, finally, one is conscious of successive, connected, discriminated wholes, one reasons. Reasoning, to be sure, more often than conceiving or judging, has a verbal constituent, yet reasoning also may be carried on without words.
Conversely, the use of the general term, proposition, or syllogism, is no sure indication of judging or reasoning. For these forms of word-series have become so habitual that one may use them without full realization of their meaning. For example, the proposition, "the apple is yellow," may not mean more to the man who speaks it than the words 'yellow apple,' that is to say, no judgment at aU, no experience of differentiated wholeness, need be involved ; and the prepositional form of the words may be a mere unconscious
reflex, due to habit. Evidently, therefore, the psychologist must be on his guard against the false supposition, that wherever proposition or syllogism is, there also is judgment or reasoning. He, of all men, must be alive to the possibility that words do not always reveal, or even conceal, any 'thought within,' but that they may be used without any meaning, for mere pleasure in their lirjuid syllables, their rotund vowels, their emotional impressiveness.
The I, or conscious self, as so far described, is an exclusively perceiving and imagining, recognizing and thinking self. But nobody merely sees and hears, thinks and imagines: rather, every self also loves and hates and enjoys and is disappointed. We shall turn now to the study of this affectively and emotionally conscious self. Emotion is, first and foremost, an intensely individualizing experience. In loving and fearing I am conscious of myself as this self and no other ; and I am, furthermore, conscious of the individual and unique nature of the friend whom I love or of the superior whom I fear. In more technical terms : both the subject and the object ^* of emotion are realized as unique or irreplaceable. In this doubly individualizing character, emotion is distinguished from perception and from all forms of thought, for in these I lay no special stress on myself, as just this individual, nor do I regard the object of my consciousness as peculiarly individual. Rather, I realize, reflectively if not immediately, that other selves see and hear as I do, and I assume that any other self must think as I do. It is true that,
as I reUcct on my life of imaginalion, I scorn to have been in my imagining a peculiarly isolated, unique self. Yet this unicjueness and indi\i(luality forms no inherent part of the imagining. In my emotion, on the other hand, T immediately realize myself as a unique self; I imd it difficult to believe that there is any other lover or hater in the world, that then, "s any grief save my grief: in a word, I individualize myself .n emotion. And with equal emphasis I individualize the object of my love or hate or fear. I love this child; I hate that man; I delight in this sunlit stretch of river. I do not love children, and hate men in general, and enjoy any river scene. To say that I love any such class or group is either mere fiction or else it is a metaphorical way of saying that I love this and this and this child, — in fact, that I cannot think of any child whom I do not love; that 1 hate every man whom I know; and that I delight in every river scene. Herein, again, emotion is distinguished from most other experiences. The objects of perception and imagination, it is true, and the objects of some forms of thought, are reflectively known as particular, — I say, for example, that 1 perceive this house and imagine this particular scene, — but such consciousness of the object as jjarlicular is a sort of after-exj)erience, not at all an immediate, inherent factor in perceiving the house and in imagining the scene, whereas it is the very core of emotion to be conscious of the individual.
In a second character, its receptivcness, emotion evidently resembles perception. In happiness and in unhapjiiness of every sort — in hope and in fear, in enjoyment and in dislike, in envy and in sympathy — I am conscious of being alTected by my environment, that is, b\- the selves and by the things of which I am conscious. " Mv soul," as Coleridge savs, lies
"passive, driven as in surges." All emotion includes this awareness of being influenced or affected — in a word, emotion is a receptive, or passive, experience. This character of emotion is often overlooked, partly because emotion is normally preceded or accompanied by very obvious bodily movements and partly because it is so often followed by the assertive, or active, conscious relations, will and faith. In the later study of these two other individualizing, yet assertive, experiences the inherent receptiveness of emotion will become more apparent.*
As so far studied, emotion is, thus, an evidently complex, receptive, doubly individualizing experience with either personal or impersonal object. Emotion as complex or inclusive experience has now to be regarded from another point of view. Perception, it will be remembered, is an experience, (i) immediately realized as receptive consciousness of externalized and impersonal object, and (2) reflectively realized as shared with other selves; it is also (3) a sensational experience. The description of perception as sensational is gained by analyzing perception, without explicit reference to the perceiving self, into irreducible elements, — of color, quality, pitch, loudness, — each belonging to a definite time. Such an analysis, which is called 'structural,' must now be undertaken of emotion. We must know whether love and fear and envy and the rest reduce also to sensational elements, — say, of warmth and of pressure
due to hcarl-bcat, — or whether they inchide other elements of consciousness. When we j)Ul the fjuestion in this way, there is h"ttle doubt about the answer. An emotion is characterized, always, as ])leasant or unpleasant (or both) : for example, liking is pleasant and terror is unpleasant; and pleasantness and unpleasantness are clearly elemental feelings. One can no more tell what one means by agrecableness or by disagreeableness than one can tell what redness and warmth and acidity are: in other words, these arc distinct and irreducible experiences.
From the class of sense-elements affections are, however, plainly differentiated. Unlike sensational elements, they are not always present in consciousness, and cannot conceivably occur by themselves without belonging, as it were, to other experiences. The fact that we are not always conscious of either pleasantness or unpleasantness is ordinarily expressed by saying that much of our every-day experience is 'indifferent' to us. The other characteristic is clearly shown by the reflection that we are conscious, not of agrecableness or disagreeableness by itself, but always of an agreeable or disagreeable somewhat, of a pleasant familiarity, for example, or of an unpleasant taste. These distinctions, of course, are not immediate constituents of either pleasantness or unpleasantness, that is to say, when one is conscious of pleasure one does not necessarily say to oneself, "this exjx'rience might have been perfectly indifferent, and the pleasantness of it belongs to its color consciousness." On the contrary, these are only possible after-reflections about the agreeableness or disagreeableness. The fact that the affections are not always present in consciousness, and that they seem, as has been said, lo 'belong to' other experience of
Some psychologists maintain that besides pleasantness and unpleasantness there are four other affective elements of consciousness (or 'feelings'); namely, excitement and tranquillity, tension, and relief.^ On this theory, there would be six affective elements of three sorts, opposed to each other two by two. In the opinion of the writer of this book, this is a mistaken view; and for the following reasons. In the first place, though emotions are rightly characterized as exciting or tranquillizing, 'excitement' and 'tranquillization' are complex rather than elemental experiences, fusions of temporal-relational with organic-sensational consciousness. 'Tension,' in turn, seems to be nothing more nor less than attention; and attention, though classified as attributive element, and so coordinate with the class of affections, is not an affection, 'Relief,' finally, seems to mean little more than absence from tension. We shall, therefore, abide by the traditional view that the elemental experiences peculiar to emotion are the two: pleasantness and unpleasantness.
Emotions are characterized also — and that by common admission — by the organic sensations which they include. Most conscious experiences contain, of course, the vague awareness of bodily processes; but in emotion these organic sensations are peculiarly prominent. The experiences of quickened heart -beat, of faintness or of dizziness, of growing warmth or of creeping chill, are factors of most emotional experiences.
The Forms of Emotion 175
Tlic mention of tlu'se experiences clue to internal bodil}changes suggests the problem of the physiological explanation of emotion. It will be convenient, however, to postpone this discussion to the fourth section of this chapter and to turn at once to a more detailed psychological analysis of emotions.
In the effort to be true to the distinctions of actual experience, we shall find that emotions are commonly grouped according to the varying relations of different selves to each other and on the basis of the contrast between pleasantness and unpleasantness. Our study of emotional experiences will start from the following outline of the basal emotions : ^ —
The fact must be emphasized that this outh'ne makes no pretence of including all forms of emotion. Two omitted distinctions should specially be named : that between certain emotions according as their objects are past or future; and the distinction, already mentioned, between exciting and depressing emotions. From tht former point of view, anxiety is distinguished from disappointment as having a future, not a past, object ; and from the latter, hatred is different from
extreme terror in that it is exciting and not depressing. All these distinctions might be added to the table of emotions, but at the risk of complicating it too greatly.
a. Personal Emotion
We have first to study the most primitive and most significant of the forms of emotion — i)ersonal emotion. It apjjears in the two well-marked phases which underlie all personal relation, as egoistic or as altruistic, that is, as laying stress on myself or on other self. W'c must, however, guard against the error of describing egoistic emotion as if it included no awareness of other self or selves. If this were true, there would be no personal emotion at all, for that demands the relation to a particular other self, and exists only in so far as it emphasizes and individuates the other self or other selves. Like and dislike, fear and gratitude, and all the rest, are obviously expressions of one's attitude to other selves, but these ' others ' are not realized as themselves caring and hating and fearing, but only as the conscious, yet unfeeling, targets or instruments to one's own emotions.
It follows from this distinction that many kindly, goodnatured feelings are rightly classed as unsympathetic. Mere liking, for example, is as unsympathetic and egoistic an experience as dislike. By this particular self one is pleasantly affected; by this other, unpleasantly. But the pleasure is as distinctly individual and unshared as the dissatisfaction. The other selves are means to one's content or discontent, and are thought of a^ subordinated to one's own interests.
discontent, the hostile fear or hate or contempt, of the man who reah"zes himself as unfavorably related to other selves. Quite as significant, on the other hand, is the unruffled good nature, the sunshiny content, the unaffected liking, or even gratitude, of the individual who feels that he is happy in his relations with other selves. The common temptation is, of course, to give to these genial feelings an ethical value, and to contrast dislike, as selfishness, with liking, as if that were unselfish. The truth is, however, that the one attitude is as 'egoistic' as the other. To like people is to realize them as significant to one's own happiness, not to identify oneself with their happiness. And, in truth, a great part of what is known as 'love' of family or of country is of this strictly egoistic nature. Dombey loved his son because the boy was ' important as a part of his own greatness' ; and many a man loves family, church, or country merely as the embodiment of his own particular interests and purposes.
It is even possible to secure other people's pleasure and to avoid paining them, not in the least to gain their happiness, but because their cries of grief assault our ears as their happy laughter delights us. The most consummately heartless figure of modern literature, Tito Melema, is so tenderhearted that he turns his steps lest he crush an insect on the ground, and devotes a long afternoon to calming a little peasant's grief. "The softness of his nature," we are told, " required that all sorrow should be hidden away from him." But this same Tito Melema betrays wife and foster-father and country, in the interests of his own self-indulgence : other people's emotions are insignificant to him in themselves; he regards them only as the expression of them rouses him to delight or to sorrow; he never for an instant enters into
The avoidance of another's pain does, it must be added, require what is sometimes called sympathy, the involuntary tendency to share the organic sensational consciousness of other people. The pain which one feels at the sight of somebody's wound is an illustration of this experience, known as ' organic sympathy.' We are, however, here concerned with emotion not with sensation.
Besides this fundamental difference between the personal emotions, liking and reverence and love, which involve pleasantness, and the opposite ones, dislike, terror, and hate, which are unpleasant experiences, we must take account also of another difference, which marks off the simpler from the more complex form of these feelings. In all these experiences, our happiness or unhappiness is referred, as we have seen, to other selves, and is realized as connected with them. When the consciousness of this relation becomes explicit, that is, when other people are clearly and definitely realized as aftecting us and as sources of our happiness or unhappiness, then those vaguer personal feelings of like and dislike give w^ay to emotions in which the realization of others is more sharp-cut and more exactly defmed. Closely regarded, the distinctions among these complex emotions arc found to be based on the estimate which is formed of those 'other selves' who are means to one's happiness or unhappiness. When these other selves are realized as greater, stronger, than oneself, the resulting emotions are reverence and terror; wdicn they are conceived as on an equality with oneself, the emotions are love and hate; w^hen they appear, finally, as weaker or inferior, the feelings are scorn and tenderness.
It is not diflicult to illustrate these abstractly worded definitions. Reverence, the individualizing, receptive, happy consciousness of a greater self, is the emotional attitude of child to father, of soldier to commander, of worshipper to God. It is the emotion thrilling through the lines of Coleridge to Wordsworth, " friend of the wise and teacher of the good," and culminating in the last verses : —
For the parallel emotion toward a self conceived neither as greater nor , as weaker than oneself, there is no precise name. The terms 'love' and 'friendship' are employed in this chapter; but to this usage it may well be objected that these are no mere emotions, but that, in their complete form, love and friendship include the active attitudes of loyalty and trust. But, named or unnamed, there is surely a happy emotion which obliterates distinctions of greater and weaker. To paraphrase Aristotle : love is the character of friendship, and by love friends, however outwardly unequal, "make themselves equal." The word 'tenderness' even more inadequately expresses the happy emotion centred in some one weaker than oneself. It is the feeling of the mother for her child, of the master for the cherished pupil, of every lover for the beloved one who is weak or afraid. It is the feeling which stirred the heart of Alkestis for Admetos, the emotion which Sokrates felt when he played, in that "way which he had," with the hair of Phaidon, as he said, "To-morrow, I suppose, these fair locks will be severed."
anny and oppression is a lix-ini; illustration of the contrast between terror or fear and haired. Why did the French peasantry, who endured the burdens of Louis Qualorze, rebel against the materially lessened impositions of Louis Seize? What is the nature of the emotional contrast between the two generations, only a century apart : in the earlier period, hapless suffering from disease, starvation, and exaction of every sort, without the stirring of opposition ; a hundred years later, fierce and furious resentment against oppression and misery? There is only one answer to questions such as these. The peasants of the older period were still bound by the traditional belief that court and nobles were naturally above them, loftier and more i)owerful than they. Their feeling to these superior beings, realized as instruments to their own undoing, was of necessity, therefore, the paralyzing emotion of terror; but the feeling, though intense, remained impotent and futile, and led to no effective reaction so long as the nobles held, in the minds of these peasants, their position of lofty isolation. The French Revolution was, in fact, directly due to the spread of the doctrine of social equality. Rousseau's teaching of the essential likeness of man to man, once it took root in the mind of the French people, grew of necessity into the conviction that peasants and nobles were no longer separated by an impassable barrier. And with this conviction of their equality, the unnerving emotion of terror gave way to hate with its outcome of fury and rebellion. So in England, four centuries earlier, the peasants rebelled under Wat Tyler not through mere discontent with industrial conditions but because the levelling emotion of hate had been excited by the teaching of the Lollard priests and of John Ball. The men of Kent and of Essex, persuaded of the
against whom they rose.
Apparent exceptions are really illustrations of this principle, for the outburst of fury against one's superior always turns out to be due to a momentary denial of his superiority, a temporary tearing of the god from its pedestal. The fear of the superior beings readily, however, reasserts itself, and this explains the temporary nature of many revolts and the easy resumption of authority. A handful of soldiers may check the violence of a mob, because t-he vision of brass buttons and uniforms inspires an unreasoning conviction of the superiority of military force, and transforms hate and rage into futile fear. The insubordinate fury of usually obedient children is like mob-violence, a temporary assertion of equality with their old-time superiors ; and like mob-fury, the anger of children readily gives way to the old acceptance of authority.
The emotion of scorn, finally, involves the conviction of another's inferiority. It is evidently impossible to despise a man, so long as one regards him as one's own superior, or even as one's equal. Contempt is, thus, the dissatisfaction involved in one's relation to an inferior person. The inferiority may be real or imagined, and of any sort ; but just as reverence or respect may be regarded as a virtue, so contempt is readily considered from the ethical standpoint, and it is rightly rated as morally unworthy if it takes account of the superficial inferiority of fortune or of station.
These emotions have other selves as emphasized object. In contrast to them are emotions whose chief object is myself. '"Tis evident," Hume says, " that pride and humility have
the same object . . . self, of which we have an intimate memory and consciousness. According as our idea of ourself is more or less advantageous, we . . . are elated by l)ride or dejected by humility. . . . Every valuable quality of the mind," Hume continues, "... wit, good sense, learning, courage, integrity; all these are the causes of j)ride, and their opposites of humility. Nor are these passions confm'd to the mind. ... A man may be proud of his agility, good mien, address in dancing, riding, fencing. . . . This is not all. The passion, looking farther, comprehends whatever objects are in the least ally'd or related to us. Our country, family, children, relations, riches, houses, gardens, horses, dogs, cloaths ; any of these may become a cause either of pride or of humility." * Spino/a sums up this conception in fewer words: Pride, or self-ajjproval (acquiesccntia), is, he says, "joy arising from the fact that a man contemplates himself and his power to act," whereas "humility is sadness arising from this, that a man contemplates his own i)owerlessness." f
Besides this obvious distinction between the hapj)iness of self-content and the unhappiness of self-depreciation, there is a difference between emotions in which the core of my happiness or unhapj^iness is my relatively independent valuation of myself and those in which my elation and dejection consist j)rimarily in my consciousness of others' estimation of me. From this point of view, we may distinguish pride, as " isolated self-esteem" in which "the mind stops at home, turns in ujion itself, and sits before the glass in pleased admiration," from vanity, the "de[)endenl and sympathetic type of self-esteem," which is "uneasy till conrirmed by
other voices; unable to refrain from inviting applause."* And, similarly, we may contrast humility with shame, the shrinking consciousness of the loathing of one's fellows. Spinoza names these emotions 'glory' and 'shame.' They arise, he says simply, "when a man believes himself to be praised or blamed."
It is not necessary to insist on just these meanings for the words pride and vanity, humility and shame. 'Vanity,' for example, is often limited in application to baseless and empty self-conceit ; and ' humility' may be used of a tranquil realization, untouched by sadness, of one's low estate. But whatever names be chosen to express the distinctions, it is important to the analyst of human emotions to recognize the experiences to which these terms are here applied. Aristotle's great-souled man who, "being worthy of great things, rates himself highly," is proud, not vain. His supreme content is rooted in self-satisfaction, and he disregards, if he does not scorn, the approval of other people. Malvolio, on the other hand, is vain: he delights in his appearance precisely because he believes himself to be the observed of all observers. The despairing self-contempt of Philip Nolan, "the Man without a Country," is so deep that he has no thought for the estimate of his companions; but Sigismond's shame is his consciousness of the scorn of the Bohemians who have heard the stinging reproach of John Hus: I came here trusting in the word of an emperor. It is probable, indeed, that the social forms of these emotions are original and primitive; and it may even be that pride and humility are never utterly self-sufhcient ; and that, in one's seemingly isolated approval or contempt of self, one is, after all, judg-
of society.
The experiences which we have so far described have all been characterized by their egoistic narrowing of consciousness, by their heavy emphasis on one's own concerns and interests, by their incurable tendency to regard other selves merely as ministers to one's own individual satisfactions and dissatisfactions. The sympathetic emotions arc manifestations of the altruistic phase of self-consciousness, the widening embrace of other people's interests, the sharing of other people's hai)piness and unhappiness. In one's sympathetic relations witli other jjeople, one regards them as possessing a significance of their own, quite aside from their relations of advantage or disadvantage to oneself, and one shares these new interests and ideals in such wise as to enlarge the boundaries of one's own experience.
Emotions of personal sympathy are of two main types: I am happy in another's happiness or unhappy in his grief. There is no English word to express the sharing of joy, and we are forced to borrow from the Germans their e.xact and j)erfect word, Mitfreude. The poverty of the English language expresses, unhappily, a defect in human nature. I certainly am quicker to sympathize with people's sorrow than to delight in their happiness. It is easier to weep to my friends' mourning than to dance to their piping, easier to share their griefs than to share their amusements, infiritely easier to console them than to make holiday with them.
The greatest distinction in these simple feelings of sympathy is in the narrowness or the widcness of them. There may be but one individual whose experience I actually share,
whose joys and sorrows 1 feci as mine. In the presence of this one other self my strictly individual happiness is disregarded, and the boundaries of my self-consciousness arc enlarged. I live no longer my own life, but this other life — or rather, my own life includes this other life. Yet my relations to all others save this cherished one may remain narrowly egoistic: I may still be concerned only for myself, and interested in these others only as foils to my emotions. Life and literature abound in examples of sympathy within the narrowest limits, of egoistic emotion giving way at one point only. Aaron Latta is a modern illustration of this attitude: he lives his self-centred life undisturbed by the wants, the hopes, the cares, of the village life about him, but he is quick to notice the shade on Elspeth's brow and the merest quiver on her lip. With a true intuition, indeed, the novelists and the dramatists have united to represent the most unsympathetic of mortals as vulnerable at some point. Dickens, the keen student of the emotions, has only one Scrooge, 'quite alone in the world . . . warning all human sympathy to keep its distance,' and represents even the Squeerses as possessed of 'common sympathies' with their own children.
Closely following upon the narrowest form of sympathy, which recognizes the claims and adopts the interests of one individual only, are family-feeling, club-feeling, college-feeling, church-affiliation, and all the other sympathies with widening groups of people. For sympathy is normally of slow growth. The more primitive emotions are naturally self-centred, and they give place only gradually to the identification of oneself, first with the joys and griefs of one's mother or nurse or most intimate playmate, then with the
emotional experiences of Ihe whole famil_\- j^rouj), later with the hopes and fears and regrets and deh'ghts of a larger circle. It is interesting lo observe that, with every widening of one's sympathy, the limiting circumference of one's own self is pushed farther outward. The sympathetic man has always a richer, concreter personality than the self-centred man. He has actually shared in experiences that are not immediately hi^ own; he has seen with others' eyes and heard with their cars, and his pulses have beat high to their hopes and joys ; his experience has been enlarged by his symj)athies.
There is something abnormal, therefore, in the checking at any point of this outgrowth of symj)athy. People whose sympathies embrace only the members of their family, their cult, or their class, arc only incompletely human, for a lack of emotional comprehension, or sympathy, marks a stunted personality. Even patriotism, so far as it limits sym})athy to feeling with the inhabitants of any one corner of the globe, deprives a man of his birthright : communion in the joys and sorrows of life with 'all nations of men,' or rather, with that which Tolstoi calls 'the one nation.'
We have, imally, to consider heterogeneous sympathetic emotions: happiness through realization of another's unhappiness, that is, malice, and unhappiness through consciousness of another's happiness, that is, envy. By common consent, these are morally undesirable emotions, yet there can be no question that they are sympathetic, as well as egoistic, that is, that they require a genuine sharing of another's experience. I cannot envy you, if I am so deeply occupied with my own emotions that I do not realize you as happy. And I cannot really know that you are happy without, in some degree, experiencing or sharing }our haj^piness.
This, to be sure, is often denied : I am said to possess the idea of an emotion without experiencing the emotion itself. But, surely, to be conscious of emotion means nothing if it does not mean to have the emotion. I may, of course, have the purely verbal images, 'happy,' 'unhappy,' 'emotion', without any affective consciousness and without any realization of myself in relation to others; but nobody's emotion can influence my own without my experiencing or sharing it to some degree. The resulting relations to other selves are, therefore, heterogeneous sympathetic, or mixed, emotions. Not only do they combine happiness and unhappiness, but they supplement a sympathetic by an egoistic emotion: the happiness which we faintly share with another, in our envy, is swamped in the egoistic unhappiness which it arouses, and the unhappiness of our fellow, dimly felt in our maliciousness, is swallowed up in a surging happiness that is quite our own.
It would be a mistake, however, to suppose that malice and envy exhaust the nature of this emotional experience. Barrie has shown us a perfect embodiment of mixed emotion in the figure of Sentimental Tommy. Never was anybody more sympathetic than Tommy, boy and man. He entered into the feeling of friend and of foe alike : divined and shared in Elspeth's loneliness, Aaron's bitterness, Grizel's passion and scorn, and Corp's loyalty. He never could have been what he was to all of them, had he not, up to a certain point, shared actually in their feelings; had he not believed in himself as Elspeth and Corp believed in him, hated himself as Aaron hated him, alternately loved and despised himself as Grizel loved and despised him. Such sympathy, as element of one's egoistic and unshared hapj)iness or unhai)pincss, is that which is here called heterogeneous sympathetic emotion.
This chapter has so far been concerned with personal emotion, the conscious relation of happy or unhappy self with other selves. But one may like or dislike the furnishings of a room as cordially as one likes or dislikes its inmates, and one may be as desperately frightened by a loaded gun as by a tyrannical master. This means that emotion, though primarily a realized relation of oneself to other selves, may be also a relation of oneself to impersonal objects.
Some emotions, to be sure, are necessarily personal. Every form of sympathy presupposes our realization of other selves, and reverence, like contempt, is felt toward selves and not toward things. Hate, also, is a i)crsonal emotion — since, although we often feel a certain irritation, more than bare dislike, for inanimate objects when they thwart our purposes, yet in these cases we ])robably personify the things at which \\c are angry. Such personification of inanimate objects is ridiculously clear in a child's anger at the stones which refuse to be built into forts, or at the doors which resist his efforts to open them; and even grown-up resentment against smoking fires and catching hooks involves a personification of the offending object.
an indi\ idualizinjf, or jKirticularizing, experience. Just as I love or hale, j)ity or envy, this particular person or these people, and do not impartially and indiscriminately care for 'anybody,' so, also, I like or dislike this special thing or these things, am bored by this monotony, and pleased with that familiar experience; and my aesthetic pleasure is always an absorption in this Chopin Mazurka, this tree white with blossoms, this Shakespeare sonnet, not an indiscriminate delight in a class or group.
We have already instanced impersonal like and dislike for things, not people. We have many experiences, also, of satisfaction or dissatisfaction with the relational aspects of things or events. Our outline names only two of these: enjoyment of the familiar, and the parallel distaste for the repeated or monotonous. Both feelings are well known: the cosey comfort of the old chair and the worn coat, even when one can find a thousand flaws in both; and, on the other hand, the flat, stale profitlessness of the well-known scene and the every-day objects. We, poverty-stricken, English-speaking people, have no noun by which to designate this latter experience: we may call it tediousness, or may speak of ourselves as 'bored,' but we are often driven to borrow one of the adequate foreign expressions, emiui or Langweile.
Like and dislike and the relational emotions are distinctly egoistic, laying special stress on myself and my condition. Among the impersonal emotions, however, are certain highly significant experiences which are embodiments of the other phase, the altruistic, self-effacing phase of consciousness. The first of these, aesthetic emotion,* must be considered brieflv: a full treatment of it would
require another volume, and would lead us far afield into domains of philosophy and of art. i^sthetic emotion is the conscious happiness in which one is absorbed, and, as it were, immersed in the sense-object. No words describe aesthetic emotion better than Byron's question : —
For the aesthetic consciousness, as truly as sympathetic emotion, is a widening and deepening of self — never a loss of self — by identification of the narrow myself, not with other selves, but with sense-things.
It is important to dwell on the consciousness of self involved in the aesthetic feeling because there is, as we have seen, a sense in which the aesthetic consciousness, because it refers to things, not to people, is rightly called impersonal. But absorption in the beautiful is never a loss of self. Most of that with which one is usually concerned is indeed lost : one's practical needs, one's scientific interests, even one's loves arid hates and personal relationships are vanished, but in place of these there is the beauty of this or that sensething, which one feels, accepts, and receives, widening thus the confines of one's personality. There is an easy introspective verification of this account of the aesthetic consciousness. Let a man scrutinize closely the feeling with which he emerges from one of those 'pauses of the mind,' in which he 'contemplates' an object 'icsthetically' : he is sure to experience a curious feeling of having shrunken away from a certain largeness and inclusiveness of experience, and though he has regained interests which he had tem])orarily lacked, he has also lost somethint; from his verv self.
From this general description of aesthetic emotion as an adoption and acknowledgment of sense-objects, an immersion of oneself in the external and objective, we enter upon a more detailed consideration of its characteristics. The aesthetic emotion is, first and foremost, enjoyment, not dissatisfaction, a mode of happiness, never of unhappiness. This follows from the completeness of absorption in the aesthetic object, for unhappiness and dissatisfaction involve always desire, aversion, or resentment, the effort to escape from one's environment. The aesthetic emotion is, therefore, a consciousness always of the beautiful, never of the ugly. Not the emotional aesthetic experience but the reflective aesthetic judgment has to do with ugliness; for ugliness is not a positive term at all, but a reflective description of an object as unaesthetic, an epithet which can only be applied after ofle has had experience of the beautiful.
The description of the aesthetic consciousness as absorption of oneself in the sense-object indicates a second character of the aesthetic experience, its attentiveness. This conception of aesthetic emotion, as involving attention, helps us account for the things which people call beautiful. It is an open question whether simple experiences, such as single colors or tones, have any beauty; but if we do attribute beauty to them, it is certainly by virtue of their intensity or distinctness, as when we admire the bright color or the distinct sound. For intense and distinct experiences are, as we know, ready objects of attention, so that it is fair to conclude that sensational experiences are beautiful, if ever, when easily attended to. A careful scrutiny of complex objects of beauty shows that they, too, are easily attended to, though for another reason. The sense-object which is beautiful is
always a unique totality of characters, and both by the unity in which its details are united, and by the individuality of the combination, it is readily attended to. Every beautiful object is an illustration of the principle. Thus, curves are beautiful, and broken lines are ugly, in part because the curve is a whole, readily apprehended, whereas the broken line is a series of unessentially connected sections, with difliculty grasped as a whole; and rhythm is beautiful because it binds into a whole, expectantly apprehended, the successive movements, tones, or words of the dance, the melody, or the poem. The more complex the parts which are bound together, if only the complexity does not overstrain the attention, the more organic the unity and the greater the beauty. By this principle we may explain what we call the development of our aesthetic consciousness. To a child, the couplet or the quatrain may well give more aesthetic pleasure than the sonnet, jjrcciscly because he can attend to the one and not to the other, as harmonious whole. He will prefer the short lines of the "Cavalier Tune" —
Consciousness of the beautiful is, in the third place, direct and immediate, not reflective and associative; that is, the beautiful is always an object of direct and immediate perception, .^n object may gain interest, significance, and value, but never beauty, by its suggest iveness. This is an important point, for sentimental moralists and even sober psychologists are constantly contrasting what is called
the beaut V of expression, or significance, with immediately apprehended beauty. We are told, for instance, that the bent figure of a laborer is 'beautiful' because the man has worked bravely and faithfully, or that an ill-pro})ortioned, wooden building is beautiful because it is a happy home. These are misleading metaphors : nothing can be beautiful which is not a direct and immediate object of sense-perception; the figure is ugly, though the man's life is an inspiration; the building is hideous, though it enshrines happiness. Nothing is gained, indeed, by confusing every value with the distinct and well-defined value of the beautiful. What we mean by aesthetic consciousness is a direct experience; and, as Miinsterberg teaches, only the unconnected, the ' isolated fact in its singleness,' can be beautiful — can bring about, in other words, the complete absorption of self in sense-object. A final feature of the aesthetic consciousness has already been suggested; it is a characteristic emphasized by Kant, by Schiller, by Schopenhauer, and, indeed, by all the great teachers — the entire disinterestedness of aesthetic pleasure. This means that the contrast between one self and other selves is all but vanished in the aesthetic experience, and that one becomes, as Schopenhauer says, ' a world-eye,' a perceiving and enjoying, not a grasping or a holding self. To enjoy a bronze or a painting because it is mine, or to delight in a view because it stretches out before my window, is thus an utterly unjEsthetic experience, for the sense of beauty admits no joy in possession, and beauty does not belong to any individual. This disinterestedness of the aesthetic consciousness explains the mistaken opposition, sometimes made, of the 'beautiful,' to the 'useful.' It is quite incorrect to hold that a useful object may not also be beautiful; and, indeed, men like
Morris and Ruskin have fairly converted even this Phih'stine age to the possibiHty of welding together use and beauty, in the ])ractiealobjectsof every-daylife, in buildings, furnishings, and utensils. But it is true that one's consciousness of the utility is not identical with one's sense of the beauty, and that one seldom, at one and the same moment, appreciates the convenience of a coflfcc-pot handle and the beauty of its curve, or realizes the brilliancy of a color and the likelihood that it will not fade. While, therefore, objectively regarded, the union of beauty and utility is the end of all the arts and crafts, subjectively considered, the consciousness of utility must not be identified with the sense of beauty, precisely because the aesthetic sense demands the subordination of narrow, ])ersonal ends.
The common distinction of aesthetic from una?sthetic senseexperiences may be accounted for in a similar fashion. The organic sensations, such as satisfied hunger and thirst, bodily warmth, active exercise, — all these are pleasant but they are not ' aesthetic' pleasures, because they are, of necessity, sharply indi\"idualized and referred to my particular self. Tastes, also, and smells are exjjcriences which serve narrow and definite ])ersonal ends of bodily sustenance. They are seldom, therefore, artistically treated as objects of aesthetic pleasure. For the beautiful object is cut off as utterly from my narrow neids and interests as from the associative connection with other facts; in the words of Schopenhauer, it is 'neither pressed nor forced to our needs nor battled against and conquered by other external things.' Thus the world of beauty narrows to include one object of beauty.
enjoyment of logical unity, often discussed under the name 'intellectual sentiment.' Every student knows the feeling, and counts among the most real of his emotional experiences the satisfied contemplation of an achieved unity in scientific classillcation or in philosophical system. The feeling should be sharply distinguished from another characteristic pleasure of the student, the excitement of the intellectual chase, the enjoyment of activity in even unrewarded search. The pleasure in logical unity follows upon this tormenting pleasure of the chase, as achievement follows upon endeavor. It clearly resembles aesthetic emotion not only in its absorption and disinterestedness, but also in the characteristic harmony, or unity, of the object of delight. For this reason, the enjoyment of logical unity is sometimes reckoned as itself an aesthetic experience. The writer of this book, however, approves the usage which restricts the application of the term 'beautiful' to sense-objects. This limitation, of course, forbids the treatment of enjoyment of logical unity as a form of aesthetic pleasure.
Brief reference must be made, finally, to a third form of impersonal and altruistic emotion — the 'sense of humor. '^ For our present purpose, it is most important to dwell upon the self- absorbing, externalizing nature of the experience. Just as we are said to forget ourselves in our apprehension of the beautiful, so also we forget ourselves, that is, our narrow individuality, our special interests and purposes,' in our appreciation of the humor of a situation. What Professor Santayana has well said of the aesthetic consciousness w'e may equally apply to the saving sense of humor : there is hardly a "situation so terrible that it may not be relieved by the momentary pause of the mind to contemplate it aesthetically "
The Bodily Conditions and Corniatcs of Emotion 197
or humorously. It is because wc have such need of j)auses, in the arduous business of h'ving, that we vahic the sense of humor so highly, and for this same reason wc find the most estimable people, if devoid of humor, so inexpressibly tiresome.
There arc as many theories of the comic as of the beautiful, but \irtually all of them agree in defining the sense of humor as enjoyment of an unessential incongruity. Narrowly scrutinized, every 'funny' scene, every witty remark, every humorous situation, reveals itself as an incongruity. The incongruity of humor must, however, be an unessential discordance, else the mood of the observer changes from happiness to unhappiness, and the comic becomes the pathetic.
This section, which concerns itself with less purely psychological considerations, will first discuss the physical and physiological conditions of emotion, — more precisely of those elements of consciousness to which a structural analysis reduces emotion. These elements include, as has appeared, at least the following: (i) affective elements of pleasantness and unpleasantness, and (2) organic sensational elements.
(i) The affections are distinguished from sensational elements in that they have no definite j)hysical stimulus, no distinct form of physical energy which corresponds with them, in the way in which \'ibrations of the ether normally condition sensations of color, and atmospheric waves condilion sensations of sound. This independence of ])hysical stimulation is admitted by everybody, so far as the mode of physical
stimulus is concerned. Klhcr or almosi)licrc vibrations, and mechanical or electrical, licjuid or gaseous, stimulus may bring about now a pleasant, now an unpleasant, now a perfectly indifferent, experience. It is true that certain sensational qualities — pain and probably also certain smells and tastes — are always unpleasant, and there may be certain sensational qualities which are always pleasant; but, none the less, every class of sensational (jualitics (except that of pain) includes both agreeable and disagreeable experiences; and many sensational qualities arc sometimes pleasant, at other times unpleasant, and again indifferent.* It follows, as has been said, that the affective tone cannot vary with the mode of physical stimulus.
Some psychologists have, however, supposed that a detinite relation may be found between the degree — and possibly also the duration — of physical stimulation and the affective experience.^ This relation is usuall}' formulated as follows: any stimulus of great intensity, and many stimuli of prolonged duration, occasion unpleasantness, whereas stimuli of medium intensity bring about pleasantness, and very faint stimuli excite inditTerent experiences. But this is not an accurate statement of the facts. Both moderate stimuli, and even stimuli which at one time are strong enough to be unpleasant, may become indifferent — for example, workers in a factory may grow indifferent to the buzz of the wheels which is intolerable to visitors; and low degrees of stimulation, for instance, the faint pressure of fingers on the skin, are sometimes pleasant. The pleasantness and unpleasantness of all save sensational experiences of great intensity seem to depend, so far as they can be explained at all, not on the physical inten-
sityof their stimuli, but on two other factors — the unexpectedness and the inlermillence of the stimuh'. The constantly repeated stimulus, unless very strong, is indifferent, whereas the unexpected stimulus occasions pleasure.
We have thus been unsuccessful in the effort to discover definite physical stimuli of the affections. We have, however, reached certain positive, though as yet uncoordinated, results. \'ery intense, and intermittent stimuli occasion unpleasantness; unexpected stimuli of moderate intensity excite j)leasure; and habitual stimuli are indilYerent. A further consideration of these results of our inquiry leads us to a study of the physiological conditions of affective elements of consciousness. These, to be sure, can be only hypothetically assigned, because they have eluded discovery by direct cxjierimental or by pathological methods. We must proceed cautiously in the absence of direct experiment, but we are safe in asserting, first of all, that there are no peripheral or surface end-organs of pleasantness or unpleasantness, since such endorgans could only be excited by s])ecial physical stimuli, of which, as we have seen, lliere are none. Tt is also probable that pleasantness and unpleasantness are not brought about by the excitation of the sensory cells in the brain, that is, of the cells directly connected by afferent nerves with the surface end-organs. For variation in the locality of these functioning cells, in the degree of their excitation, and in the number excited, have been seen to correspond, in all probability, with sensational qualities, intensities, and extensities.
Bearing in mind that any theory of j)hysiological conditions is uncertain, until it has been verified by exj)erimental observation, we may still ])rohtably guess at the ])hysiological basis for the affections." In the writer's opinion, one plaus-
iblc account of this physiological condition is the following: pleasantness and unpleasantness are occasioned by the excitation of fresh or of fatigued cells in the frontal lobes of the brain, and the frontal lobe is excited by way of neurones from the Rolandic area of the brain. When the neurones (or cells) of the frontal lobes, because of their well-nourished and unfatigued condition, react more than adequately to the excitation which is conveyed to them from the Rolandic area, an experience of pleasantness occurs ; when, on the other hand, the cells of the frontal lobe, because they are ill nourished and exhausted, react inadequately to the excitation from the Rolandic area, then the affection is of unpleasantness; when, finally, the activity of frontal-lobe cells corresponds exactly to that of the excitation, the given experience is neither pleasant nor unpleasant, but indifferent.* This theory is assumed, as working hypothesis, in this chapter. From this suggested explanation of the affective factors in emotion we must turn to an attempted account of (2) the sensational constituents.^ These are of two main classes: first, those which are brought about by internal bodily changes, especially by changes of heart-beat and of arterial pressure; second, those which are due to the movements of head, limbs, and trunk, including respiratory movemcnts.f Many psychologists have tried to discover, experimentally, exact differences between bodily conditions of pleasantness and unpleasantness respectively. J The results of these inves-
first reading of the chapter.
t On this subject, the student is advised to read James, " Psychology, Briefer Course," Chapter XXIV., pp. 373-386; or "The Principles of Psychology," II., Chapter XXV., pp. 449-471.
ligations are not unambiguous, for the difTicuItics of experimenting on emotional conditions are very great. It is, in the first place, hard to bring about any genuine emotion under laboratory conditions — to rouse keen joy or pronounced grief while one is encased in apparatus destined to measure the bodily processes; and, in the second place, emotional states are so complex that it is hard to isolate pleasantness and unpleasantness for experimental testing. The following distinctions may, however, be accepted as more or less probable: ^ —
(i) Pleasantness is characterized by a slow and strong pulse, by dilating arteries, and by bodily warmth. Unpleasantness is characterized by a fast, weak pulse and by bodily chill. This is the result best established by experiment and by introspection.
(2) Pleasantness is perhaps charactcrizerl by relatively quick and weak breathing; un])leasantness by slow and deep breathing. This conclusion is not so well substantiated.
It should be added that all these bodily conditions may conceivably occur without our being conscious of them ; but that the consciousness due to the internal changes (the consciousness of heart -beat, of warmth, of cold, and the like) are jjrobably always a part, even if an unemphasized part, of emotion ; whereas the consciousness of some, at least, of tin- external changes, of altered breathing or of actual movements of the body, is only a fre((uent and not an invariable, constituent of emotion. My amusement, for examjjle, often include-^ my consciousness of my smile, yet I may be amused without smiling.
in rcs])iralion, and in the- movements of face and limbs — condition and accompany the emotions. But we have not completed our study of the bodily conditions of emotion until we try to discover the brain or nerve changes which condition these changes in pulse, respiration, and the rest. A probable account of these brain changes is the following. First, (a) sensory brain-centres are excited through perception or imagination of a given object; next {b) the excitation of these sensory neurones spreads to the brain-centre of bodily sensations and movements, that is, to the region forward and back of the fissure of Rolando, and there excites motor cells.* This excitation of the motor neurones of the Roland ic region is then carried (i) downward to lower brain-centres in the medulla oblongata, which control the unstriped muscular coatings of inner organs of the body, such as blood-vessels, heart, and intestines. In this way the internal circulatory changes are brought about : the heart -beat and pulses are checked or increased, and the arteries (not the big ones near the heart, but the smaller, thin-walled vessels in outlying parts of the body) are dilated or constricted, thus occasioning either a flush and rising temperature or pallor and chilliness. The downward excitation is carried (2) to the striped or skeletal muscles attached to the bones of the body, and thus the ' external ' changes in breathing and muscular contraction are occasioned. Both sorts of bodily change, the 'internal' and the 'external,' excite end-organs of pressure, and the internal changes excite also end-organs of warmth and cold ; and these excitations of the end-organs of pressure and of warmth or cold are carried upward by ingoing nerves to the sensory cells of the bodily-sensation-and-movement-centre
(thf Rolandic area). The excitation of these sensory cells •s the ininu'(h'ate conch'tion of all the organic sensations (whether due to internal changes or to external movements) which arc present in emotional experience. And from the Rolandic area, excitations carried to the frontal lobe bring about that adetjuate (or inadequate) excitation of neurones which conditions the pleasantness (or un])leasanlness) of emotion.
We may illustrate this com])licated description by the hypothetical account of the bodily conditions of some special emotion — for cxamj)le, of the delight wiili wliich I hail the unexpected arrival of a friend. The conditions of this joy are, presumably : —
First, {a) the spread of excitations from the sense-centres, excited by the sight of my friend, to motor nc-urones in the Rolandic area; and {b) the excitation of downward motor neurones.
Fourth, {a) excitation of end-organs of pressure, occasioned by the internal bodily movements which always occur, and by the external muscular contractions when they occur; and {b) the upward spread of these excitations to sense-cells of the Rc^landic area. The excitation of one grou|) of these sense-cells occasions the sensations of internal warmth and pressure, which are always a part of the emotion of joy; and the excitation of another grouj) of these cells, when il occurs,
Fifth, the spread of excitations from these Rolandic senseneurones, to the frontal lobes, followed by the adequate excitation of frontal-lobe cells. This vigorous excitation may be explained, at least in part, in the following manner : the stronger heart-beat, characteristic of joy, pumps blood from the heart, and all parts of the body, including the brain, are therefore relatively well nourished. The result of this adequate excitation of well-nourished frontal-lobe neurones is the affective element of the emotion — its pleasantness or unpleasantness. A diagram may make all this clearer (see page 205) : —
in Emotion
Important to a study of emotion is a consideration of those bodily reactions which accompany and, in part, condition emotional states. They are noticeable, in the first place, as interruptions of preceding bodily reactions of every sort. On the one hand, they are interruptions of those regular and habitual reactions which normally accompany perception; and, on the other hand, they interrupt the deliberate and purposive bodily movements of thought and of will. A second character of emotional reactions allies them with sensational and with perceptual reactions : they are swift and immediate, following directly on stimulation. Emotional reactions, in the third place, like all merely sensational and like some perceptual reactions, are instinctive, untaught. The deliberative reaction to a new situation — the movements necessary, for example, in setting up a new piece of apparatus — and even
the less complex perceptual reactions — the movements, for example, with which I react to the ringing of my telephone bell — have all been accjuired, that is, learnetl through imitation of somebody else or through my individual experience of success and failure; but my caress, my shudder, my laughter, — all these are instinctive bodily responses.
Emotional reactions are classified in two ways. They arc distinguished, in the first place, as either chaotic excess-reactions or as coordinated hereditary reactions. The distinction may best be brought out by illustration. Suppose that I am seated at my desk and dictating a letter to my stenographer, in part reading from manuscript and in part composing. My consciousness is quite unemotional. My bodily reactions are compounded of (i) the habitual bodily reflexes which accompany and follow my perception of the letter which I read, and of (2) the more deliberate and hesitating reflexes which accompany my adoption of the phrases which I add. At this moment I am frightened, let us say, by the sight of a beast escaped from a travelling menagerie. What now is the character of the bodily response to this environment ? It is of course, an instinctive reaction, and it involves an instantaneous 'checking' of the behavior of the previous moment : I at once drop the letter I have been holding and I stop speaking. And it is either a chaotic and unordered reaction — a helpless shriek, and an impotent running to and fro — or it is a coordinated action of the hereditary type; for example, I run away from the beast or I attack him with some bludgeon. Professor Angell has admirably explained emotional reactions of these two types. The stimulus of the emotion — whether external object or image — checks the reaction,
liabilual or volitional, of the i)rec(.(lin<^ movfincnl, so that (in Angell's words)* "llu- motor chaniu'is of at(|uircd coordinated . . . movements are somewhat obstructed." These motor impulses "overtlow . . . into channels leading partly to the involuntary muscles," and thus resulting in aimless, futile movements, ''and partly, through hereditary intluences, to the voluntary system," resulting in useful and coordinated, though unplanned, reactions.
Within this group of coordinated and hereditary reactions a second distinction may, finally, be made. The reactions which accompany the happy emotions arc movements of advance — such movements as the baby's outstretching of his arms to his mother; the reactions which accompany the unhappy emotions are movements of withdrawal, such as the shrinking of the child ivom the unfamih'ar figure. All these instinctive hereditary reactions may be studied from the standpoint of their biological significance. Darwin and others have shown that the bodily changes in emotion are modified survivals of instinctive reactions of animals and of primitive men to Tlieir en\-ironment." The trembling of fear, for example, is an instinctive movement which takes the place of actual flight from the enemy ; the snarl of hate is a modified survival of the way in which an animal uncovers his teeth, in order to tear and devour his i)rey, and the quickened breath of anger is a survival of the labored breath of an animal or of a savage, in a lifc-and-dealh contest with an enemy, f
to read Cliaptcrs Will, and XIX. in full.
t The student should consult Darwin, "E.xpression of the Emotions," e.xamining the illustrations. For condensed statement of Darwin's teaching, cf. James, the end of each of the chapters cited on p. 200.
IV, The Significance of Emotion
The two fundamental characters of emotion press to the foreground of our attention as we turn again to the ])ractical question: What is the bearing of our psychology on our behavior? Precisely because of these basal characters, emotion is an important factor in behavior. Emotion is, in the first place, an individualizing experience: it fosters explicit self-realization and direct personal relations and it makes other people real to me. And it is, in the second place, a receptive experience, and makes me sensitive to my environment and responsive to every aspect of it. A secondary character of emotion is also significant from the i)oint of view of conduct. By its very vividness and coerciveness emotion tends to interrupt the habitual course of perception and of thought — somewhat as the emotional bodily reaction breaks in on the habitual response or on the deliberate chain of reactions. And this emotional interruption has, of course, its uses and its corresponding defects. If my habitual activities are never interrupted by emotion, I shall react in undeviating fashion to my environment for all the world like a well-wound wax figure ; and if my reasonings are never broken in upon by feeling, I am little more than a calculating machine. On the other hand, if my thinking is never secure from the inroad of my emotions, I am like a heap of fireworks, ready to be set off by any chance spark.
The practical conclusions from this estimate of the significance of emotion are very obvious and yet are worth a restatement. All of them presuppose, of course, the possibility of stimulating, checking, modifying — in a word, the possibility of controlling the emotions. On this point one preliminary observation must be made. The emotions are
only indirectly controllable. Nobody can wave a wand and say to himself, "Now J '11 be haj^py," or "Now is the time to feel mournful." This is a fact which people arc always overlooking. Yet, though one may not by a feat of will exorcise the evil passion or the gnawing melancholy there are devices for removing the conditions of emotion. 1 may mechanically turn my attention to an absorbing and distracting book or occupation; I may open my mind to some tranquillizing influence; or I may arbitrarily assume the bodily postures which accompany pleasure. I shall be most successful in these indirect efforts to expel emotion if, by their means, I can rouse a strong emotion opposed to the one which T am trying to banish. Love that is perfect casts out fear because I cannot be at the same time vividly and happily conscious of another self in equal companionship with me and yet unhappily conscious of the same self as my superior and as cause of my unhappiness. And in like fashion love may exorcise demons of unhallowed desire and of sullen melancholy. Shakespeare, great analyst of the human passions, vividly emphasizes this truth : —
"When in disgrace with fortune and men's eyes, I all alone beweep my outcast state And trouble deep heaven with my bootless cries And look upon myself and curse my fate
From this preliminary study of tlic ways of controlling emotion wc must turn back to the more specific problem: What are the helpful and what the harmful emotions? At the outset, we must recognize that emotion is an important, and indeed an inevitable, constituent of the psychic life. We are not to try, therefore, to suppress all emotion — and not to suppose that we can be successful if we try. To be universally bored or blase is for most people a pose and an affectation; and in so far as the effort is sincere it is a mere sign of incompleteness, an admission that one is only half a human being.
But though it is alike futile and mistaken to attempt to banish emotion from experience, it is none the less certain that emotions may be harmful. Emotions are positively harmful if they interfere with essential habits; they are harmful also if they do not stimulate to active consciousness — that is, to volitions or to beliefs. The first of these assertions is so obvious that it hardly needs to be enlarged upon. I simply cannot go on living unless I can protect my useful habits from the incursions of my emotions ; and I cannot carry on any train of reasoning while I am strongly swayed by my passions or by my feelings. It is even more necessary to emphasize, in the second place, the truth that emotion is not an end in itself; that emotion, though in itself receptive or passive, is significant in so far as it is incentive to activity; and that emotion turned upon itself, and issuing in no action not only fails of its particular result but inhibits the future tendency to activity. Indulgence in emotions never leading to action may become, in truth, the starting-point of actual disease, nervous and mental ; and one of the soundest methods of scientific psvchotherapy is the discovery of a patient's
■suppressed emotions,' and the efTort to guide them into safe outlets of action.* To hug one's emotions to oneself, to seek or cherish them after Rousseau's or Werther's fashion, for the mere delight or excitement of having them is, therefore, to run the risk of cripi)ling one's power to will, to choose, and to play an active role in life. Constant theatre-going and novel-reading are injurious precisely because they stimulate the emotions without providing any natural outlet of activity. The reality of this danger and the practical method of guarding against it have been well set forth by Professor James. "Every time," he says, "a fine glow of feeling evaporates without bearing practical fruit is worse than a chance lost; it works so as positively to hinder future resolutions. . . . One becomes filled with emotions which habitually pass without prompting to any deed, and so the inertly sentimental condition is kept up. The remedy would be, never to sufi'er oneself to have an emotion, . . . without expressing it afterward in some active way."t
Thjs conclusion about the relation of emotion to activity furnishes, as will at once appear, the most important criterion of the value of j)articular emotions. Emotions are of very manifold sorts and kinds, and are consequently of diverse and unequal value. In fostering and in checking emotion we must, therefore, recognize the ditTerent values of the different emotions. For the complete estimation of emotions, as adajjted to varying situations, there is here no opportunity, but the main principles of such an estimate may be stated. In brief: I should seek, in the control and development of my emotions, as complete an emotional
experience as is consistent with the function of emotion to stimulate helpful activity. On this basis, three practically significant conclusions . may be formulated. First, in and for themselves, the pleasurable emotions are helpful and the unpleasant emotions are harmful. This statement stands in direct opposition to the teaching of asceticism that pleasure is in itself an evil, but follows immediately from the principle that emotion is useful in so far as it stimulates activity. For pleasure more often and more intensely than its opposite, pain,* leads to activity. The desire to avoid pain is, to be sure, a stimulus alike to conscious and to bodily activity. But greater decisions are made, truer loyalty is shown, more seemingly impossible results are achieved through hope than through fear, through love than through hate, through confidence than through anxiety. Evidently, therefore, other things being equal, one should seek to rouse and to perpetuate pleasant emotions; and, conversely, it is absurd to urge any one to choose a profession or an occupation or a course of study because it is unpleasant and therefore salutary. It will appear immediately that many pleasant emotions are harmful; but this is always by virtue of some character other than their pleasantness.
Second, altruistic emotions, because most of them are less instinctive, are more in need of cultivation than egoistic emotions. In general, only people whose instincts have been warped by unnatural training need to be exhorted to seek happiness for themselves. Most of us, surely, would be larger and more effective selves if the scope of our sympa-
Ihics were widened, and if the happiness and unhajipiness which we sliarc with other selves were intensified. In order to widen my own personality and in order to transform merely passive emotion into active loyalty, I should therefore cultivate my altruistic emotions.
Third, neitlier the personal nor the impersonal emotions should be cherished to the exclusion of the others. This 'rule' is i)rimarily in the interest of completeness of experience. There are people who arc never stirred by the beauty of harmony, of form, or of color, who never draw breaths of satisfaction at the completeness of a demonstration or at the nicety of a logical distinction. Such people may be vividly emotional — they may be moved to their depths by personal contact, they may love and hate and envy, and may quiver with sympathy. And yet they miss part of what life might give them; and for lack of the occasional detachment from the personal, their emotional life is one-sidecl and thwarted.
The opposite defect is, however, more serious. By missing the impersonal joys of life one defrauds mainly oneself; but by lacking the personal emotions one impoverishes other selves as well. The characteristic temptation of certain temperaments is to regard the personal as if impersonal, to look at all human happenings from the standpoint of aesthetic and intellectual emotion. Thus regarded, a squalid tenement house is merely picturesque, and a defalcation is an interesting social situation. The dangers of this attitude are apparent. The impersonal emotions lead to contemplation and are perilously out of place in situations which demand action.
happy for the unha])j)y experience. But this abandonment should never be from choice of tlie unhappy-as-such. In spite of, not because of, the unhappiness which it brings me, I should exchange my delighted contemplation of the thatched cottage for a sympathetic consciousness of the discomfort of its damp and smoky interior. The estimation of the comparative value of pleasure is one of the concerns of ethics. Every student of ethics and e\ery keen observer of life admits that the desire for pleasure must be strictly controlled, not because pleasure is evil in itself but because it is so instinctively sought that it tends to displace more important objects of choice.
A brief reference must be made, in conclusion, to the unhealthy fashion of stimulating unpleasant emotion in the alleged interest of completeness of experience. The popularity of sensational novels and of problem-plays is the contemporary indication of this tendency. But nobody needs to seek unpleasantness merely in order to enrich his experience, for life is bound to furnish enough that is unpleasant. The only safe rule is never to create or to seek the unpleasant save as it leads to action individually necessary or socially helpful. Such a principle lies at the basis of a sound estimate in the New York Nation of certain widely read novels. "Their revelations of the hideous conditions of life," the Nation says, "are not calculated to make any person of good-will seek out that suffering and relieve it. . . . In a time when sensationalism and overemphasis of all kinds bid fair to be regarded as the chief literary virtues, these sordid infernos go a step farther and deal consciously in the revolting. . . . To view a brutal action may be salutary if it prompts one to knock the brute down; to penetrate the
lowest human depths, l)carinu; aid, is well; to classify a new gangrene is well if it evokes a remedy; but to i)ry about a pathological laboratory that one may experience the last qualm of disgust, and then to ex])loit such disgust for literary purposes, is to create a public nuisance."
Sharply contrasted with the receptive, passive relations of my conscious self to its object, or environment, are two supremely assertive, active, experiences: will, or volition, and faith. In perceiving, I cannot help seeing and hearing and smelling; and though I can, to a degree, control my imaginings, yet I am a victim, often, of my imagination, for, in normal as well as in abnormal states, insignificant word-series may repeat themselves with wearisome iterations, grewsome scenes may thrust themselves upon me, and bitter experiences may unroll themselves before my unwilling eyes. In emotion, finally, I am influenced by people and things, 'prostrate beneath them,' as Goethe somewhere says.* Opposed to all these receptive attitudes are will and faith : the dominant assertive relations of the self to objects of any sort. Will is a consciousness of my active connection with other selves or with things, an egoistic, imperious relation, a domineering mood, a sort of bullying attitude. In will I am actively, assertively, related to my environment, I am conscious of my superiority and my independence of it,
Every leader or captain among men is thus an embodiment of will : his domain may be great or small, spiritual or physical, civil or literary; he may be king or cabinetmaker, archbishoj) or machinist, inventor or novehst; whate\cr his position, if he consciously imposes himself on others, if he moulds to his ideals, on the one hand, their civic functions, their forms of worship or their literary standards, or, on the other hand, their furniture and their means of transportation, he stands to them in the relation of imperious, domineering, willing self.
The rebel and the stoic arc even more striking embodiments of will than the mere leaders of men. For stoicism and rebellion are instances of imperiousness, in the face of great or even overwhelming natural odds, — assertions of one's independence in the very moment of opposition or defeat. The stoic, in spite of his conviction that apparent success is with his opponent, is unflinching in the assertion of his' own domination. " In the fell clutch of circumstance," he declares the more firmly —
" Fiend, I defy thee ! with a calm fixed mind, All that thou canst inflict I bid thee do. Foul tyrant both of Gods and humankind, One only being shalt thou not subdue. ***** *
II is this altilude of mind, not any specific direction of consciousness toward a definite result, which constitutes what we call will, in the most intimate meaning of that word: a realization of one's independence of people and of things, a sense, more or less explicit, of the subordination of one's environment to one's own use, bodily or spiritual, — such a possession of oneself as is, in its completest development, a subjugation of every outlying circumstance, of every opposing self, and even of every insubordinate desire and thought. For only then is my self-assertion complete whpn I can say —
Will is thus an egoistically assertive experience. It is also (like emotion) a profoundly and a doubly individualizing experience. Never am 1 more poignantly conscious of myself as single individual, as I-and-no-other, than when I assert myself in domination over my environment or in opposition to it. And with equal emphasis I individualize the object of my will : I assert my superiority over this individual, I command this soldier, I dominate this obstacle.
There are two fundamentally important forms of will — will directed toward a future object and will without temporal reference. Will of the first type has as object a specific future event. Will without temporal object is the consciousness of my domination of opposing person or of outlying circumstance, and need not include any contemplation of future change. It is a more fundamental experience than will directed toward future object, for this latter form of will is the expression, ordinarily, of the underlying non-temporal volitional attitude. One often, indeed, issues commands solely as expression of an overbearing disposition, after the fashion of the mother who
From the objects of thought of which one is aware as related primarily to each other * objects of will, like objects of emotion, are sluirply distinguished in that lliey are immediately realized as related to the self. In truth, the assert iveness of will imj)lies the subordinate relation of objects, personal and impersonal, to me, the willing self. These future objects of will are called ends and must be further discussed.
The end of will is, in the first place, real ; that is to say, what I will, I always will to be real. Whether it be the will to make my moorings, or to fit together the pieces of a picture jjuzzle, or to resist a temptation to drive a sharp bargain, the end of mv will is always regarded as a real occurrence, in the sense that I will it to be real. This is, indeed, the distinction between the object of my will and the object of my wish. The wish no less than the volition is directed toward a future object, but whereas I may wish for a fairy godmother or for a canal-boat in Mars, the ends of my will never seem to me to be unattainable. Another obvious character of the end is precisely its temporal relation, its futurity. A moment is that which-is-linked-in-two-directions, with its past and with its future. From both past and i)rescnt the future moment is, however, distinguished by a lack of the irrevocableness which attaches to past and to present. Past and present are beyond change, whereas the future appears to be undetermined.
The object of will is realized, fmally, as in a way dej)endcnt on the willing. It is, to be sure, an open question whether there is justification for this conviction that the end is in any * Cf. Chapter IX., p. 134.
sense dependent on the volition; but unquestionably the object of will is so regarded and is thus, as will appear, distinguished from the object of belief.*
Roughly parallel with the study of the objects of will is the structural analysis — an analysis of will conceived without necessary or explicit reference to the subject-self. We are entering now upon a famous battle-ground of psychology. Some psychologists have held that there is a specific elemental consciousness characteristic of will; others teach that will is analyzable into a complex of elements mainly sensational.^ f In the opinion of the writer of this book, neither view is justified. To begin with the doctrine of the sensationalists : they teach that will consists simply and entirely in a mass of sensation, including always the sensational consciousness of bodily movement. Suppose, for example, that in rowing 1 will to feather my oar. According to the sensationalists, my will consists in (i) the sensational consciousness of the slight and mainly unnoticed movements which, instinctively, I actually make during volition, and (2) the sensational consciousness which constitutes the image preceding the deliberate voluntary movements of my rowing. This antecedent image may be either of the movement to be executed in feathering the oar, or of the way in which the oar will look when feathered. Even in inner volition, the sensationalists teach, — in the effort, for example, to solve the problem or to remember the
Will as Aniicipaiory Coii.sriotisiicss 221
forgotten date, — one is apt to wrinkle one's forehead, to clench one's fingers, and to hold one's breath; and volition is simply the sensational consciousness of these movements. Now it doubtless is true that the willing consciousness includes these sensations of movement ; but there is a conclusive objection to the view that volition consists wholly in the consciousness of such movements: experience furnishes each of us with countless examples of movement preceded by imagination of movement, which we never think of calling voluntary. I imagine an operatic air, for instance, and am surprised to find myself humming it, or I listen to an orchestra, and my waving fan moves unconsciously to the rhythm of the symphony. These are instances of movement preceded by the consciousness-of-movement, yet nobody calls the antecedent images — of operatic air or of musical rhythm — volitions; and one names the movements impulsive, not voluntary.* But this admitted difference between impulse and volition would be impossible if volition were an image constituted by purely sensational consciousness.
The discovery that volition contains unsensational elements has led to the assumption of a special volitional, or 'conative' element. But the analysis which follows, of volition, will show no trace of any such irreducible constituent;. Roughly stated, volition differs (structurally analyzed) from the mere antecedent imagination in that it includes a certain realized *anticipatoriness.' This does not mean that volition is a consciousness later realized as having been anticij)atory : rather the anticipatoriness is part of the volition. The term 'anticipatoriness' is used to indicate a complex experience including at least three factors: (i) the consciousness of realness;
(2) Ihc consciousness of the future; and (3) an experience of linkage or connectedness — the consciousness of the dependence of the end u]:)on the voHtion. Obviously these three sorts of unsensational experience correspond exactly with the relations, just discussed, of the willed object. Thus, the volition to feather my oar includes not only sensational consciousness, perceptual and imagined, of movement, but distinctive unsensational experiences, describable only as the consciousness of realness, of futurity, and of the dependence of future end on present volition. These experiences, as must constantly be reiterated, are actual psychical ingredients, as it were, of volition — as unmistakable as the sensations of movement, of color, or of sound. Since they are elemental, or nearly elemental, they cannot be described any more than sensational elements can be described ; and, unlike sensational elements, they cannot be explained and classified by reference to definite physical stimuli and to differentiated end-organ excitation. But, like sensational elements, they can be pointed out, or indicated, as indeed we have indicated them, by reference to their objects. For example, just as one may indicate to a foreigner the meaning of the word 'red' by saying that red is the visual consciousness which one has in looking at strawberries and at tomatoes, so one may indicate the meaning of the 'feeling of realness' if one say that it distinguishes the volition from the wish to ride a bicycle ; one may designate the consciousness of futurity as part of the essential distinction between my consciousness of this August day and my consciousness of a similar day next summer; and, finally, one may refer to the consciousness of the dependence of end on volition as that which marks off my will that my chauffeur shall observe speed regulations from the belief that he will observe them.
The Forms of Will 223
Of these three structural factors of the ' feeh'ng of anticij)at()riness,' two — the consciousness of the dependence of end on volition, and the consciousness of the future — arc relational experiences.* The third — the feeling of realness — is rather to be grouped with elemental attention and with the affections, the feelings of pleasantness and of unpleasantness, as an attributive clement. Like these (and unlike the sensational elements) it is not always present in our consciousness — in other words, we may be conscious of objects without regarding them as either real or unreal; and, like the attributive but unlike the relational elements, the feeling of realness is always fused with another element or with other elements of any order, f
This outline, it will be observed, concerns itself only with volition directed to the future, making no attempt to classify the delicately varying non-temporal relations of self to other selves — to distinguish, for example, imperiousness from aggression, or mere opposition from inventiveness.* The outline is based on the distinction of the will to act, or outer volition, from the will to think, or inner volition, — on the distinction, for example, of the volition to sign a check, or to fire a gun or to make an electric contact, from the volition to attend to the elusive analogy, to remember the forgotten name, or to think out the unsolved problem.
Outer volition, or the will to act, may have as object either a bodily movement or a result of movement. In the expression of James, it may have either a 'resident' or a 'remote' end. It is thus a consciousness of straining muscle or of moving hand, or else a consciousness of the effect of these movements, of the note to be sounded, the button to be fastened, or the outline to be drawn. This consciousness of the remote end may be visual, auditory, or, in fact, of any sense-type whatever. Such a consciousness of the remote end is followed by movements; but the movements are involuntary, though the consciousness is volitional, because the image which precedes them is an imagination of result, not of movement. A man wills, for example, to reach the railway station, and involuntarily he breaks into a run toward it; he has a visual consciousness of the platform, which means that a centre in his occipital lobe is excited; this excitation spreads along neurones which lead to the Ro-
Outer and Inner Volition 225
landic centres of leg-muscle activity, and by the excitation of these centres his movements of running are excited. He is conscious of the running, but only after it has begun, and he is even unconscious of some of the leg-contractions involved in the running. In other words, he actively relates himself to the railroad station, not to his leg-muscles, and the movements follow as rellexes, without being specifically willed.*
Twa corollaries about outer volition are of such importance ihal they must receive sj)ecial emphasis. The volition, in the first^place, though called outer volition, is named from.. the anticipated end, not from any perceivable resiLlt ; that is, it occurs quite independently of any external result. The fact that I am prevented, by bodily incapacity or by external circumstance, from carrying out my purpose, does not alter the volitional nature of the consciousness itself. The volition is, in other words, not an external event, but rather the anticipation of an outer event (of an act or of its result), including the feeling of anticijjation, the consciousness of the necessary connection of this definite experience with a future real event. The physiological phenomenon which follows on volition certainly is the excitation of outgoing motor neurones. But this nervous impulse may exhaust itself before the contraction of any muscles occurs; or the contraction may indeed take place, but insufTicienlly ; or, fmally, my successful action may miss the needed support of other actions. I may address the ball with inilnite pains, but to]) it ingloriously ; or I may throw the tiller hard over, but fail to bring my boat into the wind. In every case, whatever the reason of external failure, outer
nature.
The second of these corollaries of the doctrine of outer volition is the following: movfiioents conditioned, or. regularly preceded, by consciousness are not of necessity voluritary movements. Every conscious experience, sensational, affective, or relational, as well as volitional, stimulates motor reaction; but such stimulation is volition only when it includes anticipation in the sense already explained. As mere involuntary stimulus to action, every percept, emotion, or relational experience may be termed an impulse.*(A practically useful application may be made, by way of digression, from the observation that actions follow normally from impulses as well as from volitions — in other words, that actions and bodily conditions and mental states are likely to follow on the vivid consciousness of them. For, if this is true, it is evident that one's volitions should be positive rather than negative. To say to oneself, "I will not run my bicycle into that tree" is to cherish an image that is only too likely to prove an impulse to action long before the tardier volition can inhibit it. So, to resolve that "I will not lie awake to-night," or "I will not fill my mind with these corrupting thoughts," is to occupy oneself with the very experience which should be avoided. The most effective volition is always therefore affirmative: one wills to keep to the road, not to avoid the tree; to breathe deeply and sleepily, not to stop lying awake ; to " think on . . things . . . honest, . . . just . . . and pure, " not to avoid evil thoughts).
passed without detailed discussion. Like outer xolition, it is anticijjation of an end wliich is real. The end is, however, in this case, another consciousness, not a physical action or situation, but a psychic experience. The volition to remember the forgotten name or date, to guess the riddle, and to understand the working of the intricate mechanism, arc examples of what is meant by inner volitions. Compared with outer volitions, it is evident that they do not so closely resemble their ends (or objects). The volitional image of an act may be, in detail, like the act as performed; but the object of inner volition is itself consciousness, and to have the anticipatory consciousness of a consciousness, precisely similar yet not identical, is impossible. Inner volition may, therefore, be defined as anticipatory consciousness, including the idea of linkage with an end, and normally followed by partially similar experience, not by action.
h. Simple Volition and Choice
Within each of the classes, outer and inner will, there is another fundamental distinction : the distinction between simple will and choice, that is, will after deliberation. Deliberation is a conflict of will with will, an alternation in the tendencies or directions of self-assertiveness. It is a sort of clashing and warring between my varying attitudes toward different selves and things; a successive subordination to myself now of one, now of another, person ; the will to possess now this object, now that, to suppress now this inclination and again this other. I choose, let us say, to sail to Southwest Harbor instead of walking to Turtle Lake, but my choice is preceded by what is called deliberation, a sort of mental see-saw of forest and ocean consciousness: now I hear
in imagination the sound of the wind in the tree- tops, but its music is drowned by that of the water on the keel of the boat; again, I imagine the vivid brown of the brook bed and the patches of sunlight sifting through the interlaced boughs of the birch trees, but the vision is blotted out by that of the mountains rising sheer out of Somes's Sound.
Imaginings of the accompaniments and of the results of rival objects of choice may play leading roles in my deliberation. If I am deciding between a course of violin lessons and a stateroom on the Mauretania, not merely the images of fiddle and of steamer alternate, but the imagination of myself as playing "Schubert's Serenade" will be confronted by the imagination, let us say, of Winchester Cathedral Close. If I am wavering between a set of golf clubs and the new Clarendon Press translations of Aristotle, the imagination of a round on the Myopia links may be crow^ded out by a vision of myself as reading, before my study fire, a good translation of the " Metaphysics." This whole experience of alternating imaginations is attended by feelings of perplexity and unrest, the characteristic discomfort of ' making up one's mind.'
In considering the different sorts of choice, we shall do well to follow the lead of James, distinguishing 'choices without effort' from 'choices with effort.'* The difference is simply this : in the choice without effort, I fully abandon one alternative, whereas, in the choice with effort, I choose one alternative in full view of the other. The choice without effort, however prolonged and restless the deliberation
time of making it no other act or result is contemplated.
The choice without effort usually conforms with our habits of thought, inclination, ajid action. I am deliberating, let us suppose, whether to have the Bokhara or the Persian carpet. The Persian is more subdued in color, but the Bokhara is silkier in texture. The Persian is larger, but the Bokhara follows more nearly the shape of my room. So far I am undecided, but now I see that the blue of the Persian rug does not tone with the blue of my hangings, and at once, quite without effort, I decide upon the Bokhara. Or I am trying to decide whether or not to buy this volume of Swinburne. The paper is poor and the print is fine, but the price is low and the poems are complete. "I really must have it," I say to myself. " But the print is impossible," I reflect. My indecision, however prolonged, is ended by the discovery that the book is an unauthorized American reprint. Now I long since decided to buy only authorized editions of English books, and my actual decision, to reject the book, is made without effort, that is, without even a thought of the advantage of the book.
When confronted, therefore, w^ith what seems a new decision, one wisely tends to consider its relation to former choices, to fundamental inclinations, and to habitual actions. The result of such a * classification,' as James calls it, is usually a decision without effort. An action, clearly realized as essential to the fulfilment of a choice already made, will promptly be chosen. The advantage of what the older psychologists called 'governing choices' is precisely this, that they make 'subordinate choices' easy.
by longer or more painful deliberation (that is, vacillating consciousness) than the efifortless choice. The essential difference is simply this, that the choice is made with full consciousness of the neglected alternative. " Both alternatives," James says, "are steadily held in view, and in the very act of murdering the vanished possibilit}-, the chooser realizes how much he is making himself lose." George Eliot has suggested this experience in the story of Romola's meeting with Sa^'onarola, as she sought to escape from Tito and from Florence. "She foresaw thai she should obey Savonarola and go back. His arresting \oice had brought a new condition to her life, which made it seem impossible to her that she could go on her way as if she had not heard it; yet she shrank as one who sees the path she must take, but sees, too, that the hot lava lies there ^ *
The most strenuous deliberations of all these types are those of the moral life: the fluctuations between good and evil, right and wrong, desire and obedience. Lifelike descriptions of deliberation are, for this reason, almost always accounts of moral choices. Of this fact the dramatists and the novelists give abundant illustration; and even on the pages of the moralists one may find vivid suggestions of the warring of personal tendencies in dehberation. "I see another law in my members," St. Paul exclaims, "warring against the law of my mind." "Clearly there is," says Aristotle, "besides Reason, some other natural principle which fights with and strains against it."
III. Thp: Bodily Conditions and Correlates oe Will
A statement concerning the neuraj conditions and the motor consequents and accompaniments of volition will conclude this chapter. So far as the neural conditions are concerned, there is little to sa_\' : the brain cliani^es, wliatever they are, which condition the feeling of realness and the relational consciousness of time, along with the ever present excitations of sense-centres, must be the physiological conditions of will. More significant is the distinction, already made, of voluntary movements, as delayed and hesitating, from the impulsive movements following on perception and emotion. The delay is especially marked in deliberate acts; yet every voluntary act (that is, every act preceded by an anticipatory image of itself or even of its end) must be performed less promptly than an action excited mechanically and instantaneously without the intervening brain excitation corresponding to the anticipatory imagination.
The relation between these volitional reactions and reflex, instinctive reactions should be noted carefully. Instinctive actions are untaught, and all reflex acts (whether instincts or lajjsed habits) are immediate, whereas our volitional and our thought reactions are always learned through imitation or through individual exjjcricnce, and are always delayed. Regarded, however, merely as muscular contractions, without reference to their immediacy, to their orgin, or to the consciousness i)receding and accomj)anying them, voluntary movements may be similar, as well as dissimilar, to purely instincti\e reaitions in a giwn situation. Indfcd, the simple movements of which a comi)licated xoluntary mo\ement is composed — the bending, grasping, pulling, for example —
cannot dilTcr from these same movements performed as mere reflexes. And one may also definitely will to perform an originally instinctive act, in a word, one may supplement instinct by will. It follows that voluntary, like instinctive, emotional reactions of the egoistic type may be classified as reactions of withdrawal or of advance (here, of aggression). It has been pointed out already, and the fact will later be reemphasized, that voluntary reactions of all sorts tend to be replaced by immediate and habitual reflexes. In truth, the development of the life of consciousness always tends to suppress the direct motor volitions. Almost all bodily movements are better executed when our aim is directed toward the result to which they lead, that is to say, when the end of volition is an 'outer object,' not an imaged bodily movement.
I. The Nature and Forms or Faith and Belief
Faith, as distinct from will, is an adopting or acknowledging, not an imperious, demanding phase of consciousness; it lays emphasis not on myself but on the 'other self.' In the attitude of will, I subordinate others to myself; in that of faith or loyalty, I submit myself to others. In the mood of will, I am 'captain of my soul'; in my faith, I acknowledge another leader. Yet faith, like will, is an assertive, not a receptive, attitude of one self to other selves. It is no emotional sinking beneath the force of opponent or environment, but a spontaneous, self-initiated experience, the identification of oneself with another's cause, the throwing oneself into another's life, or the espousal of another's interests. In the words of Edmund Gosse : " No one who is acquainted with the human heart will mistake this attitude for weakness of purpose;" it is not "poverty of will" it is "abnegation." More accurately, such a relation is a supreme instance of faith ; and men of faith have always, like the heroes of Hebrew history, "subdued kingdoms, wrought righteousness, obtained promises, stoj)ped the mouths of lions," and this, through the active identification of themselves with great selves, great ideals, and great theories. Primarily, this attitude of acknowledgment and adoption is a relation to other selves: in other words, the object of faith is a self t)r selves. By belief,
on the other hand, is meant the assertive attitude of a self to an impersonal objeet. A man has faith in his father, his physician, his fellow student, liis God; he believes the necessity of tariff reform, the doctrine that acquired characters are inherited, the dogma of the inspiration of the Bible.
Evidently faith and belief, like will, are assertive and doubly individualizing experiences, with personal or impersonal, external or non-external, 'real' objects. Structurally analyzed, faith and belief — still like will — include the elemental consciousness of reality.* So much for the likeness: faith and belief differ from will mainly in that each is, as has appeared, an altruistic, not an egoistic, an adoptive, not an imperious, attitude toward other selves or ideals or facts. A second difference is the following: the object of belief is always an object congruent with its environment. That which seems real to me at the same time seems harmonious. It follows that the objects of belief are of the most varied sort, but that they all agree in being regarded as congruent. When objects of our perception are called 'real,' by contrast with objects of our imagination, they are known as harmonious with each other: the meeting-house which I see accords perfectly with its surroundings, the mosque which I imagine is incongruent with every architectural feature of this New England town ; the electric bells which I hear are congruent with the sounds of the city streets, the strains of the " Pastoral Symphony " which I imagine are unrelated with . my entire surroundings.
Faitli ami Belief 235
real, according as il is comparccl with one set of facts or w ith another. James has briUianlly ilkistratcd this truth under the heading, "The >hiny Worlds of Reality," and has suggested seven such worlds,* ineludini^ the worlds of sense, of science, of abstract truths, of fiction, and of individual opinion. The motion of the sun, which is real in the senseworld, is thus unreal in the world of science; Goethe's Lotte, though unreal in the sense-world, is so real in the world of poetry that we sharply contrast with her Thackeray's parodied Charlotte, whom we unhesitatingly pronounce unreal. And these distinctions mean merely that the motion of the sun is a [)henomenon, congruent with the facts of our every-day observation, — sunrises, moons, and twilights, — but contradicted by the Copernican conception of our earth and the other planets of our system, in revolution about the sun; and that the romantic Lotte is a figure congruent with the life and environment of Goethe's W'crther, whereas Thackeray's prosaic Charlotte is utterly unrelated to the Werther world of Goethe's creation. Faith and belief are thus distinguished both by the feeling of realness and by the feeling of congruence; and the objects of faith and belief are harmonious with their environment.
Besides this fundamental difference between faith and belief, on the one hand, and all forms of will, two distinctions, must be named between the ends, or objects, of will as directed toward the future, and the objects of belief. These objects of belief, in the lirst j^lace, are not necessarily future. One may believe a past or a present as well as a futuie event, as when, for example, one believes that Kleisthenes reformed
the constitution of Athens, or that some one is at the front door. In the second place, the object of beUef is not regarded as in any sense dependent on the belief. My belief that my new fur-lined cloak will be sent home to me next Thursday differs from my volition that it shall be sent home, because the belief lacks, what the volition has, a sense that this antecedent consciousness has a certain bearing on the result which will follow. In terms, therefore, of structural analysis, belief differs from will not only because the consciousness of the future is unessential to belief, but because belief includes a relational consciousness of harmony or congruence, and lacks the relational consciousness of the dependence of future on present.
Brief mention only need be made of the physiological conditions and of the bodily reactions characteristic of faith and belief. Of the brain conditions little need be added to what was said of the neural conditions of will.* The bodily movements which accompany faith or belief resemble those which follow on will in being hesitating, or deliberative, but differ from them in a marked way. For, whereas will-reactions are movements of opposition, of aggression, and of withdrawal, the reactions characteristic of trust and of belief are movements exclusively of approach: they are imitative and cooperating reactions.
Certain corollaries of the doctrine of faith or belief, as characterized by the feeling of realness, are so important that they demand consideration. It should be noted, in the first place, that side by side with the experience of realness grows
up what may be called a feeling of not-rcalness. This I-^ evidently a c()mj)osite of the consciousness of oi)[)osition wiili the consciousness of reality. Neither the consciousness of realness nor that of unrealness can be a first consciousness in any life, because both are learned through experience of such contrasts as that between ])erception and imagination, fulfilment and hope, execution, and volition, in illustration of the fact that the feeling of unrealness is not a primitive experience, James supposes * 'a new-born mind' for whom experience has begun, 'in the form of a visual impression of a hallucinatory candle.' " What possible sense," he asks, "for that mind would a suspicion have that the candle was not real? . . . When we, the onlooking psychologists, say that it is unreal, we mean something quite definite, viz. that there is a world known to us which is real, and to which we perceive that the candle does not belong. . . . By hypothesis, however, the mind which sees the candle can spin no such considerations about it, for of other facts, actual or possible, it has no inkling whatever." From this correct doctrine that the naive mind has no inkling of an unreality, James and Baldwin and other psychologists draw, however, the erroneous conclusion that the undisputed, uncontradicted objects of the primitive consciousness are felt as real. The "newborn mind," James says, "cannot helj) believing the candle real," because "the primitive impulse is to alTirm the reality of all that is conceived." But the proof that no object is primitively regarded as unreal falls far short of a proof that it is thought of as real; and, on the contrary, our observation of ordinary experience shows us many instances in which we are conscious neither of realness nor of unrealness. When I *0/>. cii., Vol. ir., p. 287.
am really absorbed in the adventures, for example, of ISIonte Cristo or in a Giovanni Bellini "Holy Family," I am not saying to myself, "this event is not historical," or "this is a portrait figure." In a word, I am conscious neither of realness nor of unrealness, but exclusively of stirring e\'ent and of glowing color.
The second of the corollaries from the doctrine of this section is the following: Though faith and belief certainly include the consciousness of reality, such consciousness may be so vague and unemphasized as to be truly an unimportant constituent of the total belief or faith. This fact is of high practical importance, for the doctrine of faith is most often obscured by confusing it with the bare consciousness of reality. A certain consciousness of reality is, it is true, essential to the active attitude toward selves and toward things, that is, essential both to faith and to will. But the mere awareness of reality is a very subordinate part of the experience of faith or belief. Faith is always an active, personal attitude toward another self; belief is always an active, personal attitude toward things, events, or truths; and both faith and belief involve, but are not exhausted by, a consciousness of the realness of selves or of things.
The relation between faith and the mere awareness of reality is most often discussed on an ethical basis. We receive, from great teachers of righteousness, fervid exhortations to have faith and to believe. But still other teachers warn us, as solemnly, that it is alike irrational and immoral to proclaim an obligation to hold opinions. These moralists insist that it is meaningless to assert the ethical superiority of one opinion to another, and they teach that the alleged duty, to hold this or that view of reality, is in opposition to the only
intellectual oMii^ation, uns\vcr\-ing honc^t\■ in investigation. This revolt against the "duty to believe" would he justified, if it did not j)resui:)i)ose a wrong interjiretation of the exhortations to faith. The truth is, that the great moral teachers always regard faith as j)ersonal acknowledgment of great selves and of great personal ideals. Such acknowledgment may involve, it is true, a certain consciousness of reality, and is never possible toward self or toward cause which is held as definitely unreal. On the other hand, such a personal acknowledgment does not presuppose any reasoned conclusion or any philosophic conviction about reality, and may even exist along with an unemphasized or a fluctuating consciousness of the reality of the self whom one follows or of the cause which one espouses. The (kity to have faith is always, therefore, the obligation lo identify oneself with the persons or the causes which seem the highest; and the exhortation to faith is always, on the lips of the great teachers, an incentive to loyalty. Thus, the New Testament commands to believe emphasize, always, the need or the duty of an affirming, consenting, personal attitude toward a divine self, and do not require that one hold an opinion about him; and the great creeds, also, are expressions of a ])ersonal relation. For, from this j^oint of view, a conception of the duty of faith may clearly be held, since personal relations, not convictions of reality, are the objects of obligation, and since faith is the assertive, adoptive attitude of one self toward another.
Faith and belief are thus described as assertive, doubly individualizing ado})tive attitudes to objects of any sort, and as distinguished by the elemental consciousness of realness and by that of congruence. An attempt to classify will show that,
like volition, faith and belief may be inner or outer, that is, may consist in the acknowledgment of ideal or of deed, and may be deliberative or simple. Deliberative struggles of faith with faith, of belief with belief, are universal experiences. Antigone's faithful love for her l.-trother in opposition to her obedience to the state, the loyalty of the Soeur Simplicc to Jean Valjean battling with her devotion to the ideal of truth, Robert Lee's allegiance to his state in conflict with his love for the Union, — are classic examples of an experience to which nobody is a stranger. Midway between this form of deliberation and the purely voluntary conflict of will with will — the alternating impulses to subordinate to oneself now one, now another, person or external thing — are the crucial struggles between will and faith. The crisis in the life of Neoptolemos was such a conflict between will, the impulse to crush Philoctetes despoiled of his weapons, and faith, the loyal acknowledgment of the rights of Philoctetes and the active adoption of his cause. Romola's deliberation, also, is essentially the vibration between these two fundamental tendencies toward self-assertion and self-effacement, toward the satisfaction of her own craving for a new life and the acknowledgment of a higher authority than her own desire. Both these are instances of an alternation, not between one willing tendency and another, but a fluctuation between will and faith, the egoistic and altruistic tendencies, the imperious and the acknowledging modes, the decision to lose one's life for another's sake or to save it.
II. The Significance of Faith and of Will Faith and will stand in such close relation that the practical outcome of the study of the two experiences is
The Significance of Faith and of Will 241
wisely formulated in a single section. Tt is certain that only in will and in faith — in my self-assertion and in my dc\'0tion — do I come fully to myself; and that only in will and in loyalty, only as assertive, active self — as leader or as follower — do I influence my environment. Obviously, therefore, these are practically significant experiences; and indeed all other forms of consciousness — memory, reasoning, and, notably, emotion — are estimated always not for themselves merely, but as material or incentive for self-assertion and for loyalty. No quickness of discernment, no power of thought, no depth of emotion, can ever take the place of what may be named energy of spirit. He who lacks it may well echo the cry, " Ce n'est pas de conseils, c'est de force et de fecondite spirituelle que j'ai besoin."
The evident outcome of this conviction of the supreme value . of activity is to stimulate me to cherish and to foster my will and my loyalty. This statement must at once be modified by two important observations. To begin with: assertivcness, in either of its forms, is out of place in some situations. There are times when I have no responsibility for action, when I would better contemplate or obser\'e or enjoy with utter receptivity, abandoning myself to stimulations from my environment. In the second place, even in my active relations, I should aim to reduce the number of my specific volitions and acknowledgments. Will and faith are, essentially, the active attitude, imperious or adopti\'e, of the self as a whole to other self or selves, and to inclusi\'c interests or to complete situations. Therefore will and faith are not most effectively directed to single acts or thoughts; but these result, with greater precision and with distinct economy of consciousness, not from the specitic volition, but rather from the
underlying will and from the wide-reaching loyalty or belief. It is true that I am not always capable of these inclusive and fundamental volitions and loyalties. While I am training myself to unaccustomed habits of mind or of body, and whenever will and faith are made difficult by opposing inclinations or desires, then I must make frequent special volitions and must espouse near and not far-away ideals. I must learn to dance, for example, by practising steps, that is, I must will the special movement of the foot and bend of the body. And the most effective way to make myself study an uninteresting subject may wtU be to will the mechanical operations of rising, getting and opening my book, following with eyes and with voice the lines and paragraphs. But these detailed and repeated volitions are characteristic of the will-in-training, not of the disciplined and educated will. When I have learned to dance, it is sufficient for me to direct my will to the accomplishment of a certain figure, and when I have habituated myself to study, the thought of the subject to be mastered will be followed mechanically by the movements involved in reading. In a word, reactions once willed tend to become involuntary, and, indeed, bodily reactions tend to become unconscious; and not only involuntary and unconscious bodily reactions, but immediate and unwilled mental reactions are likely to be more precise and exact than those which result from specific volition. Only when we no longer have to will the particular turn of the wrist or position of the hand are these movements mechanically accurate; only when we no longer need to bend to our will the words of poem or of formula can we put it to adequate use. In technical terms, the objects of our will and of our faith should be, as far as possible, inclusive and 'remote,' and our specific acts and
It thus a])|)ears that self-development involves a gradual reduction in the number of our volitions and beliefs. In like fashion, deliberation should give place to simple volitions and beliefs. In the beginning, almost every situation which involveseither will or faith calls for deliberation. There is a possible alternative to every action, and every decision may be debated. But unquestionably the ideal is to attain volitions so comprehensive and beliefs so fundamental, so farreaching, that the particular acts and conclusions of life follow from them without anticipation or as results of simple volition and faith. The Rubicon once crossed, Julius Caesar has no place for further deliberation; the road to Rome once taken, Victor Emmanuel need not pause till the breach is made in the wall by the Porta Pia; his allegiance to the party once fully given, William Gladstone has no need to debate this issue as every new bill is introduced into Parliament. In other words, when once the governing purpose is formulated, when the large allegiance is given, lesser decisions become effortless, former deliberations become needless; even simple volitions, for the most part, give place to unpurposed conclusions and acts. This is the reason why the lives of great men are always, relatively speaking, simple lives. So fundamental and abiding are the great choices which they make, so encompassing and deejjly rooted is their loyalty, that they perform naturally, even mechanically, the trivial acts and conclusions on which lesser men deliberate.
We have so far spoken of will and of faith as coordinate forms of assertiveness or self-activity, setting aside the important difference between them. But it must already have
appeared that both — the egoistic, dominating assertivcness of will and the altruistic, adoptive assertion of faith or belief — are essential aspects of the complete self. Most of us are prone to overestimate the significance of will. Like the little boys in their play-regiments, we all want to be officers, and we extol leadership at the expense of loyalty. But selfassertion, though it deepens, cannot widen, my self-realization; imperiousness and domination may be relatively external attitudes toward my environment. Only if I adopt and espouse and take into myself the aims and ideals of other selves do I make of myself what I may be. Even more obviously, I intiict irreparable wrong on my fellow if I imperil his individuality by subduing his will to mine, by imposing my personality upon him; and I fail of the contribution to the social good of which I am capable, if I do not follow where others lead and espouse causes which I have not initiated. It is a commonplace of every-day ethics that only those who have learned to obey know how to lead, and the study of the lives of the really great leaders makes this clear. Only the second-rate commanders are sticklers for recognition. "I will hold his horse for him if he will win me a battle," Lincoln exclaims of one of his generals.
It is equally one-sided, though perhaps not equally common, to follow where one ought to lead, to imitate where one ought to initiate, to obey where one should take command. The truth is that both will and faith, both self-assertion and loyal acknowledgment, are essential factors of the complete life. Each is a manifestation of the deepest individuality, for the great leader cherishes instead of repressing the individuality of his followers; and the whole-souled disciple expresses himself in his devotion.
Most of the forms of consciousness of which individual psychology treats are, or may be, social: in other words, they include, or may include, a consciousness of relation to other selves. Personal emotion, loyalty, the attitude of command — even reflective perception and thought — involve my experienced relation to other selves. In a narrower sense, the term ' social consciousness ' is applied to the awareness of my relation not to an individual but to a group of selves. There are two main types of social group: the mob, or crowd, and the society. The first is a group of selves, of whom each imitates the external acts and the unreflective consciousness of the others. The mob, hoAvever, in so far as it concerns the social psychologist, is consciously imitative. It is probably true, to be sure, that mob-actions may be unconsciously performed. The most serious-minded may be carried out of bounds at an exciting football game, and may wake up to find that, quite unconsciously, he has himself joined lustily in ear-splitting yells during several mad minutes. But this unconsciously active mob is the concern of the sociologist, and only incidentally of the psychologist. The social psychologist's interest is chiefly with the group of pcoi)le who realize their imitativeness, who are conscious, however vaguely, of
shared experiences and actions, who know ihal they are joining the shout of a thousand voices, or that they are rushing on in a great, moving mass of i)eo])le. Such vague social consciousness the people of the mob almost always possess.
We have next to remark the strict limitations of the mobconsciousness. The individuals who compose it share each other's perceptual and emotional exj)erience, but their actions are too precipitate to admit time for thought, and they are too deeply swayed by emotion to be capable of loyalty or of deliberate will. The mob-consciousness is not only fundamentally imitative, but utterly lacking in deliberation and reflection, and it is therefore capricious and fantastic. For this reason, the acts of a mob are absolutely unpredictable, since they spring from the emotions, notably the most temporary of our subjective attitudes. The fickleness of the crowd is, therefore, its traditional attribute; the mob which has cried aloud for the republic rends the air with its Vive le Roi, and the Dantons and Robespierres, who have been leaders of the crowd, become its victims.
What is sometimes called the insanity of a mob is, in reality, therefore, a psychological, not a pathological, phenomenon. Every emotion and passion gains strength as it is shared, and is characterized by reactions of increasing vigor. The accelerated force of primitive emotions, shared by scores and hundreds of people, is for a time irresistible, the more so because both emotions and the acts which go with them are unchecked by reasoning or by deliberation. No one supposes that the crew of the Bourgogne deliberately trampled women down in an effort to reach the boats. No one imagines that the Akron mob would have set fire to the public buildings, when they knew that the man
whom they sought had escaped, had ihcy reasoned the matter out. Seamen and citizens alike were a prey to elemental passions uncontrolled by deliberation.
The activities of a mob may, none the less, be constructive as well as destructive, ideal as well as material. Gustave le Bon, a brilliant French writer, lays great stress on the capacity of a mob to perform capriciously generous deeds as well as cruel ones; and he instances the crusades as example of a great altruistic mob-movement. "A crowd," Le Bon says, "may be guilty of every kind of crime, but it is also capable of loftier acts than those of which the isolated individual is capable." It is, however, perfectly unequal to any logical conclusions, any reasoned acts, any purposed, planned, or deliberately chosen performance. Whether it drive the tumbril or rescue the Holy Sepulchre, its action is purely emotional and caj)ricious, and it takes its cue unreflectively from the leader of the moment, for "a man . . . isolated . . . may be a cultivated individual ; in a crowd he is a barbarian."
Many modern writers, Le Bon among them, believe that the crowd or mob is the only social group. They thus completely identify the crowd with 'society,' teaching that the mob-consciousness is the only type of social consciousness. From this doctrine we have good reason to dissent most emphatically, for we clearly fmd in human experience what has been named the reflective social consciousness. We may compare, for illustration, the reflective national consciousness with mob-patriotism. Everybody is familiar with the mob-activities of so-called ])atriotism: the shouts, the fire-crackers, the flag-wavings. They are all a part of the contagious feeling and action of a lot of consciously, but
unreflcctivcly, imitative selves. A reflective national consciousness is an utterly different sort of exj)ericnce. The possessor of it has certain deep-seated social conceptions, ideals, and purposes; these have their significance to him as shared with a group of selves who are consciously related with himself and with each other. These principles and ideals would be meaningless to the reflectively social individual, if they were merely his own. Yet he individually adopts and promulgates them, and he acts them out at the primaries, at the polls, and in public office. Such a reflective national consciousness may well be emotional, but it is not purely emotional, and its emotional attitudes are constant, not temporary and capricious.
Different forms of college spirit illustrate the same distinction. To cheer oneself hoarse at the athletic meet, and to join the men who carry the hero of the games in triumph from the field, may be a mere manifestation of mob-consciousness, an unreasoned, unpurposed wave of feeling, which carries one off one's feet in the contagion of a great enthusiasm. But there is also a deliberate college spirit. The student is profoundly conscious that his pursuit of a wellshaped academic course, of a life of close social affiliations, and of an honorable college degree, is the aim of hundreds of other students. He realizes that he is imitating and, in some ways, leading them, and that they are both imitators and leaders of each other and of him. He more or less clearly recognizes that his advance is an alternate imitation of his teachers and his fellows, and a reaction against them. His degree has a purely social value dependent on other people's estimate of it. In a word, his college life is consciously and reflectivelv social.
The Reflective Social Consciousness 24Q
These illustrations liave paved the way for a flefinition of the reflectively social consciousness, as (i) the reflective adoption of, or domination over, the external activities and the conscious experience of other selves, who (2) arc regarded as forming a social group. Such a group of reflectively social persons may be called 'society' in contrast with a crowd or mob.
There is need to emphasize the truth that the reflective social consciousness is not merely imitative. The reflectively social person is aware of his power to lead, as well as of his capacity to follow. This tendency of the developed social consciousness has been greatly underemphasized. Monsieur Tarde, for example, believes that the essential nature of society is imitativeness. "Socialite," he says,* " c'est I'imitativit^." It is perfectly evident that this definition leaves out of account the characteristic attitude of the leader of society. Even those who have confused society with the mob have been the first to acknowledge the leader as related to the mob, yet not a member of it. "A crowd," Le Bon declares,! " is a servile flock — incapable of ever doing without a master." In truth, however wide the place we make for imitation as a social function, it can never displace spontaneity and leadership. The charge is lost when the officer falls, and the mob disperses when its leader wavers. Customs and conventions and fashions are imitations which are dominated by invention, and every institution is, as Emerson said, 'the lengthened shadow of a man.' Nobody can deny that these masters of men, these captains of industry, these world-conquerors, are men possessed
of social consciousness. \Vc certainly cannot attribute social feeling to the Old Guard and deny it to Napoleon. We cannot assert that the doers of the law have a realization of a j)ublic self, society, and that the makers of the law are without it. The sense of moulding tlie common purpose, of inflaming the public feeling, and of inciting a group of selves to imitative action, is as truly a social consciousness as the realization that one is imitating the thoughts and feelings and acts of a group of similarly imitative selves, at the inspiration of the same leader.
This dominating phase of the reflectively social consciousness does not belong to the great leaders and masters only. On the contrary, every reflectively social individual may assume the dominating, imperious attitude, as well as the imitative, acknowledging attitude. Anybody may, moreover, take this attitude not only toward individuals but toward society — the reflectively social group whose members are realized as either imitative of each other or as dominating each other. The consciousness of this relation of influence lies at the basis of what is known as the realization of one's social duty. One may go to religious services, for example, and observe church festivals, not as a personal duty, but because one believes the observances socially valuable, and is conscious of one's actions as likely to affect other people's. More than this, as our study of will has suggested,* a dominating, not an imitative, attitude toward society is entirely possible when one is not master of a situation, and when, rather, one is leading a forlorn hope or, single-handed, defying a mob. Thus, the experience of Sokrates was profoundly social when, in the Heliastic Court, he stood alone
for a lc<:;;il trial ot" I he generals of yEgos[)otami, while the Athenians, beside themselves with horror over the unburied crews, were crying out for fjuick vengeance on the leaders of that luckless sea-hght. Certainly Sokrales was conscious of himself as opposing, not a single man nor any fortuitous aggregate, but all Athens, a composite group-self whose members were being swept on in a universal passion to a common crime.
The most important form of the reflectively social consciousness is the moral experience. Ethical systems differ, indeed, at many points and, in particular, some include and others exclude the consciousness of obligation as an essential factor of the moral consciousness. But all systems, with the one exception of that form of hedonism which teaches that individual pleasure is the chief good of life, unite in the admission that the moral life involves an altruistic recognition, by one individual, of the claims and of the needs of others. The great moral teachers — Jesus, Aristotle, Spinoza, Kant, and Hegel — always conceive morality as realized relation" of myself to others, and found all formulations of specific duly on the conception of myself as social being (ttoXitlkov !^6t)ov),* as 'member of the universal kingdom of ends ' t (^r <i^ neighbor and brother. By some moralists, indeed , the moral consciousness in its social phase is not distinguished at all from the reflective social consciousness, and any reflective realization of oneself, as member of a group of related selves, is regarded as a definitely moral experience. In the ojjinion of the writer, there is, however, a difference between the merely social and the ethically social attitude: any group,
however small, of related selves, can be the object of a genuinely social consciousness, but the moral consciousness keeps in view the relationship, not of any single group, but of all human selves, with each other. The purpose of ethical conduct, therefore, is the realization of complete union between one self and all other selves. In other words, when I am acting morally, I am not aiming at my own pleasure or profit, I am not working to secure the ends of my friend, my family, my society, or even of my state : I am inspired by a wider purpose, an ideal of the harmonized claims and needs of all individuals.
II. Imitation and Opposition
As so far studied, the social consciousness has been distinguished according to the social group — mob or society — which is its object. We may profitably discuss, a little further, two contrasted aspects, imitation and opposition, of the social consciousness and incidentally of social activities. Opposition in its two forms, invention and imperiousness, is the attitude of the social leader; imitation and the allied relation of obedience are the attitudes of the follower, the member of the group, to the leader. We are here especially concerned with imitation and invention. Each, it is evident, is a phase of learning, a widening of individual experience; but whereas imitation involves no social advance, but merely our individual progress, opposition in the form of invention implies an addition to the sum of human acquisition.
If we try to discover how many of our daily acts are repetitions of those of other people, we shall perhaps be surprised at our conclusion. We rise, breakfast, travel by car or by train, enter workroom or office or shop, work behind
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machine or counter or desk, lunch, work again, return to our houses, dine, amuse ourselves, and sleep; and innumerable other peojjle, near and far, are also breakfasting, travelling, working, dining, and sleeping. Yet we are in error if we reckon all these repeated activities as imitations. An absolutely isolated individual, without opportunity to imitate any one, would nevertheless eat and sleep and move about. An imitation is an act or a conscious experience conditioned by another, or by others, similar to it. Repeated activities are not, then, of necessity, imitations, but may be independent expressions of an individual, though common, instinct.
When, however, we weed out from the tangle of our repeated acts and experiences those which are mere instinctive or else accidental repetitions, a goodly growth of imitations still remains. For example, though we sleep, not because others do, but because of the conditions of our individual bodies, yet we sleep on the ground or on beds, and from eight o'clock till five, or from dawn till noon, simply because the ])eople who educated us and the people who surround us do the same. So we eat, not because others eat, l)ut to satisfy individual needs; yet we eat tallow or rice or terrajjin, we eat with our fingers or with chop-sticks or with forks, and we eat from the ground, from mats or from tables, partly because people have taught us these ways, and ])artly because these are the manners of those about us. Again, our wanderings from place to place are unimitative, instinctive activities, but the manner of our travelling, on horseback, by automobile, or by acn)])lanc is, oftener than we think, a caprice of fashion.
The list of our imitative acts is scarcely begun. The rootwords of a language, except such as are instinctive vocal outcries, are imitations of nature sounds, and language is always
acquired by imitation. Peo])le s])eak English or Dutcli or Portuguese not accidentally, — as the child suggested, who feared that his baby brother might speak German, in place of English, — but through imitation of the people about us. Our handwriting is an imitation of our teacher's, and the earliest handwriting was abbreviated from the pictured imiitation of natural objects. We bow to each other instead of rubbing noses ; we lace on calf boots instead of binding on sandals; we read and write short stories instead of threevolumed romances; we revel in sociological heroines in place of romantic ones ; and we study psychical research and no longer burn witches. But all these acts, ideals, and tendencies are directly due to custom or fashion, that is, to imitation. We do and think all these things, and scores of others, because others act and think in these ways.
Two forms of imitation are socially significant: fashion, or imitation of the present, of contemporary selves and facts, and tradition, or imitation of the past, of one's ancestors, their thoughts and their acts. In Paris, for instance, dress is regulated by fashion, which changes with every season, and every woman therefore dresses as her neighbor does. In Brittany, dress is a tradition, and every woman dresses as her great-grandmother did; the paysanne, who moves from one province to another, tranquilly, and as a matter of course, wears a coiffe which is as tall as that of the neighborhood is broad, as pointed as that is square, as unadorned as that is richly embroidered. This adherence to tradition as opposed to custom is the real distinction between conservative and radical. The latter need not himself be original and inventive, but he is friendly to innovation and receptive of the customs of his contemporaries; he l)reaks with the past and
Another ilistinction is that between ])hysieal and j)sychic imitation, imitation of movement and imitation of emotion or idea. Uniformities of movement — for example, those of drilling soldiers or of training oarsmen — are illustrations of the first class, and fashions in creed or in theory, such as the evolution hypothesis or the modern movement in favor of simplified spelling, are instances of the second sort. The truth is, however, that conscious imitation is only secondarily of thought or of act. Primarily and fundamentally, the object of imitation is another self or other selves, an individual or a social group; and the imitation consists in a conscious attempt to make oneself into this fascinating personality or to become one of this attractive circle. So the child imitates his father's stride, because it is his father's, not from any intrinsic interest in the movement in itself, and is a fierce Jingo because his father sides with the imperialists, not because he himself inclines toward these principles rather than toward others. The life of the child shows most clearl}-, indeed, the intensely personal nature of imitation. The development of his own personality is, as Royce has taught * by the successive assumption of other people's personality. Now, he imitates, or throws himself into, the life of the explorer; he harnesses his cocker spaniel to an Arctic sledge made of an overturned chair, and he reaches the North Pole ahead of either Cook or Peary. A little later, his ideals are incarnated in the persons of military heroes: you will find him gallantly defending the pass at Thermopylae behind a breastwork of pillows, or sailing out to meet the
Spanish Armada on a |)rccarious ship of tables ; he adopts { military step, organizes his companions into a regiment, attempts military music on his toy trumpet, cultivates in himself, and demands from others, the military virtues of obedience and courage. And in all this he is primarily imitating people, and is imitating specific acts and ideals, only as they are characteristic of these people.
One need not turn, indeed, to the life of childhood for illustration of the fundamentally personal nature of imitation. For there surely are few adults whose aims are not embodied in human beings. WTiether one's ideal is that of the student, the physician, or the diplomat, it stands out before one most clearly in the figure of some daring and patient scholar, some learned and sympathetic physician, some diplomat with insight and training. One's effort often explicitly, and almost always implicitly, to be like this ideal self, to realize in oneself his outlook and his achievements; and one is consciously satisfied with oneself when one has completed an investigation, made a diagnosis, or negotiated a treaty as this ideal self might have done it. The moral life, perhaps, offers the most frequent illustration of the personal character of imitation. Our ethical ideals live in the person of some great teacher, and our moral life is a conscious effort to be like him; our aims, also, are set before us as a supreme personal ideal, and we are bidden to "be perfect as our Father in Heaven is perfect."
Leaving imitation, we have briefly to consider the main forms of the contrasted tendency. These have already been named: on the one hand, mere opposition to other selves and to their thoughts and their acts; and, on the other hand,
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the leader's attitude, whether domination or invention, toward these other selves. In its simjjlest form, opposition consists in the will to be different from others. Unquestionably, this tendency has been underrated, in consequence of the almost exclusive interest of the sociologists in the function of imitation. In all save the most servile forms of the social consciousness there occurs alongside of the impulse to follow one's neighbors the instinct to show oneself unlike them, or — as the impulse is sometimes formulated — to show one's own individuality. We are most likely, of course, to find opposition 'writ large' in the actions of children. But the mischief of a child which prompts him quite wilfully to say 'dog' or 'cow' when he knows well that he has spelled c-a-t, to run when he is expected to walk sedately, and to talk when silence is demanded, is merely a more obvious expression of the pposition instinct, which lies at the basis of all eccentricity in dress, repartee in conversation, and inventiveness in science or in art. Throughout these varying manifestations we may descry the tendency to be different, to attain what Royce calls the ' contrast effect,' quite for its own sake and without effort to influence other people. In this way, 'opposition' is distinct from the kinrlred form of domination, or command, the spirit of the leader of crowds and the organizer of societies.
It must be pointed out, in conclusion, that imitation and invention are never sei:)arate in the sense that some people and some achievements are imitative and others inventive. The truth is that every normal person unites in himself, in varying proportions, these two fundamental tendencies of consciousness. Nobody could be absolutely original, if that means unimitative; and conversely, one could hardly be a self withs
out some trace of opposition to one's environment. Thus, the most daring inventor makes use of the old principle, and the most original writer is imitative, at least to the extent of using language. On the other hand, few copies are so servile that they are utterly undistinguishable from the model.
The intimate union of the two tendencies is shown, also, by the fact that the usual road to inventiveness is through imitation. In truth, any honest effort to imitate intelligently must result in transformation rather than in mechanical copying. The healthy mind simply cannot follow copy without the spontaneous and unexpected occurrence of suggestions for change — of hot air instead of steam, an iambic metre in place of a trochaic, burnt umber rather than sienna, or zinc solution in place of chloride. It matters not whether we work at machinery, at poetry, at painting, or at chemistry: we all become inventive by trying to imitate. A curious, yet common, result of this relation is the inventor's inability to realize the extent of the changes which he brings about. Fichte, for example, supposed that he was merely expounding Kant, until Kant disclaimed the exposition and stamped Fichte's doctrine as an injurious and heretical system of thought.
Not only is it true that invention is always by way of imitation. It is also certain that the practically successful, that is, the permanent innovation, is the one which can be readily imitated. The inventor of machinery, so complicated that the common man cannot use it, will not succeed in introducing his machines, and the promulgator of doctrine, so profound that few men can apprehend it, will not greatly influence contemporary thought. This is the reason why the most original thinkers are so seldom leaders of their ov^ti
age; why, for cxanipK', the teachings of Sokrates, of Jesus, of (lalileo, and of S])inoza exerted so little intluenee on contemporary thought. On the other hand, the brilliantly successful man almost always has that highest grade of commonplace mind which strikes out nothing essentially new, hut which is }et keenly susceptible to most suggestions, selecting from these, with unerring good judgment, the readily imitable features. "Too original a thought is," as Baldwin says, "a social sjjort." Neither Rousseau nor the French Revolution, he ])oints out,* could make a democracy of France; for centuries under absolute rule had unfitted the French to imitate and to adopt ideals of libertc, egalile, f rater nit e. For a like reason, Constantine could not christianize his legions by baptizing them ; and indeed nobody ever yet foisted on a group of jieople an\- ideal which they were unprepared to imitate.
I. Typical Personal Relations
From the conception of psychology as science of myself in relation to my environment, personal and impersonal, it follows that every concrete personal relation may be the basis of a psychological study. My relation to this friend and to that, to brother or father or wife or child, to my employer or to my servant — every one, indeed, of the relations, in which my life consists, maybe reflected on, analyzed, and explained after this manner of the psychologist/ The truth is, however, that a very healthy instinct prevents us, ordinarily, from this sort of analysis of our personal relations. We are too deeply absorbed, in living these relations, to reflect about them from the dispassionate scientist's point of view. We hesitate, and rightly, to pluck out the heart of our own mysteries ; we prefer to love and to have faith, to sympathize and to enjoy, to command and to yield, without rendering up to ourselves a balanced account of our attitude to other people. But though we rarely expose our personal relations to the dissecting knife of the psychologist, there is yet no reason why the text-book in psychology, in so far as it treats of the relations of selves, should not supply the lack of scientific analysis in our own lives, by furnishing us with a series of studies of typical, personal relations — studies, for example, of the filial, the fraternal, or the civic relation, or even more general studies,
after the fashion of Hegel's analysis of typical moods of youth — the romantic, the Quixotic, and the Byronic. But there is a practical reason why the text-book on jjsychology does not, ordinarily, include such studies of typical and universal relations. The novel and the drama have already usurped this function of the psychological treatise, and just because their characters, however typical, are also particular and highly individual, therefore the psychology of novel or of drama is more absorbing and closer to life than that of any treatise. It follows that the novel has become, in some degree, the popular introduction to psychology.
The novel or drama is, of course, a study in the psychology of personal relations only. With the enumeration of structural elements of consciousness and the assignment of each to a physiological condition, it is only incidentally concerned; but the complexity and richness of the relations of its dramatis persona; are the \ery soul of it. The interest of a Shakespeare play docs not centre in the scene — the witches'. heath or the field of Agincourt — nor in the rhythm and melody of the verses, but in the developing and contrasting relations of the central figures to each other and to the lesser characters. Thus, the plays of which King Henry the Fifth is hero are a study of a youth of prominently active nature, in whom the emotions are undeveloped and unaccentuated. The love scene is sufficient proof of this : King Henry complains that he has "no genius in protestation," and that he " cannot look greenly nor gasp out his eloquence," but though he doubtless himself believes that he lacks only cxj)ression, the discriminating reader realizes that he is not capable of deep emotion, and that e\en while he laughs and plays jjranks with FalstalT, and makes love to Kate, he is never carried out of
himself, never a prey to feeling; in a word, never in passive emotional relation to anybody, even to his sweetheart. Always, therefore, on the battle-field or in the court of love, he is the plain soldier, actively and imperiously related to men, whether he hand them their death-warrants or give them his gloves as favors, whether he boast of his army's prowess or hearten his soldiers in their discouragement.
But though, for the most part, we are content to leave in the hands of dramatist and of novelist the treatment of concrete personal relations, there is one such relation so universal, so significant, and so often misapprehended, that we shall here consider it. This is the relation of human to divine self.
II. The Religious Consciousness
The study of religion may be undertaken from several points of view. One may study the history of religions, tracing the development of one from another and taking note of the place of religion in the life of different peoples; or one may study the philosophy of religion, assigning to its objects a place in the whole universe of reality. Fundamental, however, both to the history and to the philosophy of religion is the psychological study of the religious consciousness. Such a study must begin, like every psychological investigation, by a study of my own consciousness, but will be supplemented by reference to historical records of religious experience. Its specific starting-point must be some admitted definition of the religious consciousness. Many definitions may be found, but simplest and most adequate, in the opinion of the writer, is the conception of religion as the conscious relation of human self to divine self, that
If there were space to argue in detail for this conception of the religious consciousness, one would first of all point out that it lies at the base of all historical forms of religion. As is well known, living beings and nature j)henomena are the objects of the i)rimitive religious consciousness. Ancestor-worship is the most important form of the worship of conscious beings ; fetichism and the worshij) of the heavenly bodies are the extreme forms of the nature religions. Now it is obvious that the worship of the dead warrior or patriarch, and indeed the worship of any person, or even of any animal, living or dead, is a conscious relation of the worshipper to another self. But it seems, at first sight, as if the worship of a nature phenomenon could not be in any sense a conscious relation to a greater self. A fetich is an insignificant object, a bit of bone or a twig or a pebble, not a living being; and sun, moon, air, and water, the gods of the nature religions, are inanimate beings. A closer study, however, shows that these objects, fetiches as well as sun and moon and stars, are worshipped, not for what they arc, but because they are looked upon as embodiments of conscious selves. And no Aryan, we may be sure, ever bowed down before the Sim, feeling that his god was a mere fiaming, yellow ball. He worshii)ped the sun as a being apart from him and infinitel}- greater than he, yet none tlu' less a self, however * For Notrs i and 2, rf. .\p{)ciiciix, Section X\'.
vaguely conceived. Nature souls, in the words of Pfleiderer, a well-known liislorian of religion, "are originally nothing but the livingness and active power of the phenomena of nature, conceived after the analogy of animal and man as willing and feeling beings." *
If this were a book about religion, instead of being a book about psychology, it would go on to show that the systems which seem to diverge from this conception are no true exceptions. It would show, also, that the history of religion chronicles, in a sort of pendular succession, a reaction of two motives, one upon the other. A given religion, while it must include both factors, emphasizes either the superior power of its gods or else their essential likeness to human beings. In the lower forms of animism, for example, there is little difference between god and worshipper; and the gods of the Hellenes, who live among men, feasting, plotting, making love, come perilously near to losing the divine attribute of power. The higher nature-deities, on the other hand, are revered as immeasurably greater than human beings.
The history of religious rite offers another proof of the personal nature of the religious consciousness. "To speak boldly," Clement of Alexandria says, "prayer is conversation with God." t In similar fashion, Tylor defines prayer as "the address of personal spirit to personal spirit." ff The prayer, often quoted, of the Samoyed woman on the steppes shows very clearly how simple may be this communication of the human with the divine. In the morning, bowing
* "Philosophy of Religion," Vol. III., p. 237. Cf. E. B. Tylor, "Primitive Culture," Vol. II., pp. 185 and 294. t " Slromatum," Vol. VII., 242, d. tt Op. cit., Vol. II., p. 364.
down before the sun, she said only, 'When thou risest, I too rise from my bed,' and in the evening she said, 'When thou sinkcst down, I too get me to rest.' * Here we have neither petition, confession, nor explicit adoration, but mere intercourse, that is, acknowledgment of common exj)ericncc. Prayer may be, indeed, a mere request for material good like the Gol<l Coast negro's prayer, "God give me rice and yams, gold and agries, give me slaves, riches, and health,"* or it may be a prayer for forgiveness, like the Aryan's cry, "Through want of strength, thou strong and bright God, have I gone wrong; have mercy, almighty, have mercy; " f but whate\'cr its form, ])rayer, like sacrifice, is always the communion of the human with the more-than-human sj)irit. This introductory reference to the history of religions and of religious rites prepares us for our sj)ecific problem, the nature of the religious consciousness. The conception which we have gained enables us, in the first place, ft to limit the essentials of the religious experience. Ritual and ceremonial, theories of heaven and hell, and even hopes of immortality, are religious only in so far as they grow out of the consciousness of God or grow up into it ; in the realization and immediate acrpiaintance with God, the religious experience has its centre and its circumference. We shall gain a truer understanding, therefore, of the religious consciousness, if we do not regard it as an experience radically difTerent from the other personal relations of our lives. For if God be just a greater self, then one's attitude toward him
cannot be utterly unlike one's attitude toward a powerful human friend or chief. In our study of the religious consciousness, we must thus be guided throughout by the analogy of human relalionshij)s.
Now human beings are, first of all, liked or disliked, feared or thanked, loved or hated, and in the same way the religious experience is always, certainly in part, emotional. At its lowest emotional terms, it includes at least the feeling of the dependence of the human on the divine. But ordinarily the religious experience is far richer in emotion, and there is, indeed, no significant phase of human feeling which may not as well characterize the relation of man to God as that of man to man. Abject fear, profound gratitude, bitter hatred, or devoted love may be factors of the religious experience.
We have found, however, in our analysis of personal relations, that there is an active as well as a passive attitude to other selves, a relation of faith or will, as well as an emotional relation of fear or reverence. This active acknowledgment of loyalty or faith is the second characteristic phase of religious experience. It may be touched by emotion, yet it is sometimes an utterly unemotional acknowledgment of the divine self, a submission to what one conceives to be his will, an adoption of what one looks upon as his ideal, a resolute loyalty unlighted by emotions supported only by a sober and perhaps rather dreary conviction of duty. It may be questioned whether there is a
Wc arc thus brought, face to face, with the significant problem regarding the connection between the religious and the ethical experience. Our defmilion of religion, as relation of the human self to the divine, ])rovides us with a standard by which to test the frequent claim that morality is religion. This claim is often strongly opposed on historical grounds. It is pointed out that primitive religions are full of positively immoral customs and rites, that the Borneans, for example, gain new spirits by head-hunting, and that the Oceanians have a god of thieving, to whom they offer a bit of their booty, bribing him to secrecy with such words as these: "Here is a bit of the pig; take it, good Hiero, and say nothing of it." * Such an argument, however, is inadequate, no matter how firmly establislicd the facts on which it is based. For though Borneans and Oceanians and all other savage people perform acts, which we call wrong, as parts of their religious observance, it may be that they do not thereby violate their own moral codes.
The opposition between religion and morality lies deeper. The religious experience is fundamentally a consciousness of God or of gods, a realized relation of the worshipper to a spirit or to spirits who are greater than he and greater also than his fellow-men. The moral consciousness, on the other hand, is, as has ap])eared, a form of the social consciousness, a man's recognition of his place in the whole interrelated organism of human beings. Now, just as any human relation is incomj)lete and unworth\-, if it lacks ihr
moral experience, the consciousness, in some sense, of obligation toward another self, so the religious consciousness is superficial, unhealthy, and fragmentary, if it does not include the acknowledgment of duty toward God. But though religion without morality is ethically degrading, it is none the less religion. Any conscious relation to God, however low and lifeless, however destitute of moral responsibility, is religion; and no morality, however sublime, no life, however noble, is religious, if it lack this conscious relation to God. It follows, of course, that a bad man may be religious and that a good man may lack the consciousness of his relation to God. Undoubtedly, therefore, certain ethical systems are better and safer guides than certain religious creeds. Religion, however, is not and cannot be morality, simply because religion is, and morality is not, a conscious relation of human self to the divine.
The aesthetic, almost as frequently as the moral, experience is mistaken for religion. The profound emotion, with which one falls upon one's knees with the throng of worshippers in a great cathedral, is named religious awe, though it is quite as likely to be what Du Maurier calls mere 'sensuous attend)' is sement.^ The stately proportions of nave and transept, the severe beauty of pillar and arch, the rich coloring of stained glass, the thrilling sounds of the organ, and the heavy odor of the incense may hold one's whole soul enthralled, and leave no room for the realization of any personal attitude to a God who is in or behind all this beauty. In the same way, the absorbed study of nature beauty is a self-forgetful, but not, for that reason, a religious, experience.
modern tendency to class experiences as religious if they do not deal directly with material needs and conditions. But the very breadlh and comjjrehensiveness of these conceptions make them, in the writer's opinion, valueless. It is indeed true that the religious, the ethical, and the iesthetic consciousness are alike, in that they are, in a greater or less degree, altruistic rather than merely egoistic experiences. It is, however, misleading to confuse relations which, though similar in one respect, are none the less sharply distinguished.
Our study of the religious experience has not yet even named what is ordinarily accounted its most important factor: the conviction of God's reality, or — as it is commonly called — belief. The truth is that belief, in this sense, is not a part of any personal experience, that is, of any relation of one self with another. We are not occupied, in our personal relationships, with reflections upon one another's reality: we merely like or dislike each other, and are loyal or imperious. We may, to be sure, be conscious of the reality of (jod and of our human fellows, but this reflection upon "reality is usually a phase of the philosophical consciousness, and not even an ingredient of the religious experience. Certainly, a bare conviction of the actual existence of another self, human or divint-, by whom one does not feel oneself affected, to whom one is utterly unrelated, is not a personal experience at all. A belief of the reality of the deposed Turkish Sultan, Abdul Hamid, is no personal relation with him; and the mere persuasion thai there exists a Supreme Being does not constitute a religious experience.
that no ri'lationship with God is possible to one who is distinctly convinced that there is no God. Some degree of the conviction of God's reality must, therefore, form the background of every religious experience, except the primitive personal relation in which one neither questions nor believes.* But this sense of God's reality has unsuspected gradations of assurance, lying between the extremes of doubt and reasoned conviction. The consciousness of God's reality may attain the completeness of philosophical dogma, but it may, on the other hand, be incomplete and illogical; it may be firmly held or it may be feeble and vacillating. For the truth is, as we have seen, that this consciousness of reality is, at most, a secondary and unemphasized part of religious experience; and religion is, as we cannot too often repeat, a relation with God, like our relations with our fellow-men. In Fichte's words: "Herein religion doth consist, that man in his own person and not in that of another, with his own spiritual eye and not through that of another, should immediately behold, have, and possess God."
APPENDIX
This Appendix contains: (i) Bibliographical lists and footnote references. (2) Critical discussions of disputed problems in psychology, and supplementary notes upon topics briefly treated in the body of the book. (3) An account (Section III.) of the human body, in particular, of the nervous system and of the sense-organs, which amplifies the condensed statements of the preceding chapters. (4) A brief section (XVI.) on abnormal psychology. (5) A collection (Section XVII.) of questions, designed to test the student's first-hand understanding of the facts of psychology, and following the order of topics discussed in the successive chapters of the book.
The references to literature are in no sense exhaustive. They are fullest in the case of the difficult subjects and with reference to the topics most under dispute. Few references have been given to the standard text-books and, on the other hand, an eiifort has been made to take account of recent periodical and monograph literature. For other bibliographies, the student may consult: M. W. Calkins, "An Introduction to Psychology," 1901, pp. 492 ff. (with supplement to the bibliography ■ in the second edition, 1905) ; E. B. Titchener, "Experimental Psychology, Qualitative Experiments, Instructor's Manual," 1901, passim, and Appendix II., and "A Text-book of Psychology," 1909, passim ; also, the yearly Index of periodical literature published by the Psychological Review.
a. psychology as science of ideas
§ I. Psychology, as we have studied it, is the science of self in relation to environment. This conception must be compared with two others widely held. According to the first of these, psychology studies not the self but the succession of ideas (so-called mental processes) one upon the other, each as belonging to a definite moment. From this ])oint of view, the psychologist is concerned not with the self as perceiving, but with the percept ; not with the self as willing, or in assertive relation to other self or thing, but with the volition — in a word, not with the self as conscious of objects, but with consciousness regarded impersonally without reference to any self.
In the opinion of the writer of this book, this conception of psychology is self-consistent and possible. In other words, consciousness may be treated, scientifically, as series of ideas; and percepts, images, thoughts, and the rest may be analyzed, classified, and explained by reference to parallel physical and physiological phenomena. But there are two conclusive objections to such a procedure. In the first place, it arbitrarily neglects a part of our immediate consciousness, and, in the second place, it olTers an
* Sections I. -XV. of this Appendix correspond, each for each, with the fifteen chapters of the body of the book. Each section is divided into subsections, indicated by Arabic numerals; and indices from each chapter of the book refer to these numbered subsections. The page headings of the Appendix refer back to those pages in the body of the book on which the Appendix roinments.
inadequate description of consciousness. To begin with the first of these criticisms: on this view, psychology is science of ideas. But I cannot he conscious of an idea except as idea of a self; implicitly, if not explicitly, I am always conscious of a self, as having the idea or experience. If, therefore, I defme psychology as science of ideas, I raise the inevitable question: ''whose idea?" and then refuse arbitrarily to answer the question.
Idea-psychology, in the second place, though it unquestionably offers a scientific treatment of consciousness, does not adequately describe the different forms of human experience. The characteristic methods which it shares with all forms of psychology are, (i) structural analysis and (2) classification and explanation* by reference to regularly preceding, accompanying, and following physical and physiological conditions. But our study of psycholog}' lias surely shown that perception and recognition and thought, and, more obviously but no more truly, emotion, will, and faith, are incompletely described when analyzed into merely structural elements and referred to bodily conditions. Perception is, indeed, indistinguishable from imagination except as it is regarded as a shareable and not a private experience; emotion is not merely pleasant or unpleasant : it is an individualizing and a receptive experience. For both the reasons which have been named, the conception of psychology, as science of ideas, must be rejected as an unsatisfactory programme for the psychologist,
A second contemporar}' conception of psychology is as science of mental functions, or functional psychology'. This doctrine is not so clearly cut nor so precisely formulated as that of ideapsychology, for the word ' function' is used with different shades of meaning by different writers of this group^ Common to all 'functional' theories is the conception of function as activity; but — partly, no doubt, because of the indefiniteness of this term ' activity '
— many funrtional psvcliolojfists (K'fiiu' it more precisely as reaction directed toward environim-nl ; and ol'teii |jro( eed to describe the reaction as biologically useful.*
To this, as a com])lete concei)tion of psycholog)', there is an objection exactly ])arallel to the first of those advanced against ideapsychology. A function, whether defined merely as activity or as useful reaction to environment, is the function of a functioner; and there is no activity which is not the activity of an actor. Therefore, I simply cannot study mental functions without at the same time studying the functioning self. For just as the study of ideas raises the unavoidable question, "whose idea?" so the consideration of mental functions directly involves the (juestion: " functions of whom?" To detine psychology as science of mental functions without referring the functions to the functioning self, is, therefore, an entirely artificial proceeding.
More closely scrutinized, functional psychology turns out, in the second place, to be either a synonym for self-psychology or else, once more, only a partial psychology. If the term 'function ' be taken with the meaning 'reaction to environment,' and if the environment be then described, in Professor Angell's words, as * social ' and not merely 'physical,'! it must follow that a 'function' is a social relation, ■ — in other words, a [)ersonal attitude. If, on the other hand, the term 'function' be taken in a strictly biological sense, then the account of different sorts of consciousness as different reactions to environment, — as adaptations or variations, as self-preservations or propagations, — these accounts will explain and classify psychic phenomena, but will in no sense describe them psychologically. To call fear, for example, an instinctive, self-preservative reaction of withdrawal, classifies and (in a way) explains the emotion of fear, but no more describes it than the statement, "a Watteau painted fire screen protects from the heat of the fire" describes the Watteau figures. The classification of a psychological experience as biologically useful is both correct and significant, but so far from fulfilling the requirements
of psychological analysis, it is not psychological description at all. Such description is, indeed, impossible without the study of a self, in ]iersonaI relation, emphasized or unemphasized, receptive or assertive, egoistic or altruistic, to an environment which is personal as well as biological.
I. Answers to Objections
The discovery that many psychologists oppose or ignore this conception of psychology, as science of self, obliges us to marshal the arguments for the theory. We may profitably begin by considering the objections which have been urged against it. These are chiefly three. It is objected, in the first place, that the conce])tion of self, however justified, is a philosophical rather than a scientific conception. This objection is, perhaps, too technical to be discussed here in detail. Those, however, who believe with the writer, that any fact open to everyday observation — a stone, a word, a manoeuvre — may be scientifically studied will see no difliculty in the conception of a scientific study of facts so universally admitted to exist as selves.
One form which this objection takes must, however, be opposed with energy. Briefly stated, it consists first in identifying the self of psychology with some philosophical conception of self and then in arguing, rightly enough, that the philosophical conception is out of place in psychology. But between the philosophical and the psychological conception of the self there is a well-marked distinction. The psychologist does not ask whether or not the self is material or immaterial, inherently worthy or worthless, endless or finite. By self (or subject, ego, mind, soul) the psychologist may mean much less than the philosopher means. Certain characters of the soul as conceived by mediaeval and modern philosophy are entirely excluded from the psychologist's self. Obviously, therefore, the self cannot be drummed out of the psychologist's camp by arguments directed against one form or another of the philosophical conception.
A second objection to the doctrine of self as set forlli in this I)ook is l^rought forward by some of the functional jxsychologists. This conception of the self is, they urge, too exclusively psychological. VVe know no disembodied selves, and the psychologist should therefore study the mind in the body. Or, as this theory is sometimes staled, the unit or basal conception of j)sychology is the psychophysical organism, the unity of mind and body. To this objection the following reply may be made: Unquestionably, the self whom, as psychologists, we study, is a self in close relation to a body; and the study of the physical conditions and of the bodily reactions accompanying consciousness is of great importance. But there is no complete 'unity of mind and body.' By this distinction they implicitly refer the physiological functions to the physiological organism, the body, and the psychical functions to a conscious functioner, the self.* Psychology may well treat this conscious functioner as its peculiar subject-matter.
A final objection is urged against self-psychology (and, for that matter, against functional psychology) by the idea-psychologists. These claim that the structural analysis into elements — sensational, "affective, and the like — is possible only if consciousness be conceived as stream of ideas. If this objection were well-founded, it would be decisive; for it is evident that perception, for example, is sensational ; that emotion is affective — in a word, that consciousness is incompletely described without the structural analysis into elements. But the self-psychologist rightly denies the premiss of this argument. One can as well analyze * my perceiving' as 'a percept' into sensational elements; one can as well reduce * my fear' as 'a fear' to elements among which unpleasantness and organic sensations are prominent.
2. Positive Considerations
The answer to objections is an insufficient basis for any theor}'. The doctrine of psychology as science of self has, however, a more independent foundation — the testimony of introspection. Because I am directly conscious of a unique, a relatively persisting self in relation to its environment, therefore I assert the existence of a self and scientifically study its constituents and relations.
It follows that the self-psychologist has no way of answering an opponent who asserts, "I have no consciousness of self." In other words, psychology as science of selves can be studied only by one who believes, or assumes, that he is directly conscious of himself. But even to an opponent who denies the fact from which he starts, the self-psychologist can at least show the plausibility or respectability of his position by pointing out, first, that some or all of those who deny the existence of a self-for-psychology implicitly assume the existence of such a self; and second, that many psychologists of admitted worth explicitly adopt the conception.
To substantiate the first of these statements, one has only to read the books of the idea-psychologists and to notice how constantly they describe and define consciousness in terms of the self, or I. Professor Ebbinghaus, for example, though he describes the soul as "nothing save (nichts ausser) the totality" of mental contents, none the less says that the soul is "a being," that it "has thoughts, sensations, wishes, is attentive or inattentive, remembers {erinnert 5/'c/^), etc." * And Dr. Witasek, though he teaches that " we ( ! ) find in our consciousness only ideas, feelings, etc., and not something else besides which should be fundamental to them," yet says unequivocally: "Psychic facts belong to individuals: a feeling, for example, is either mine or somebody else's." f
The idea-psychologist has, it is true, two answers A this charge of making implicit use of the conception of self . In/the first place, he urges that he means by 'self,' as he uses the term, merely my
body — either my physical organism as a whole or my nervous system in particular. But in this case he should regard the l)ody, not the mind, as the real object of psychology; and this is foreign to the point of view of idea-psychology. Again, liie opjjonent of self-p.sychology justifies his use of its words by the oi)servation that, j)rovided he deline his terms, he has a right to employ everyday language in a technical sense. If, then, he define 'mind' as 'sum-total of ideas,' and 'self or ' I ' as 'human body,' he may say " I fear," and should be understood to mean: "A process occurs which is referred to the human body, and is analyzable into unpleasantness and organic sensations." The conventional expression, 'I,' he holds, no more binds the user to the obvious ever^'day meaning of it than the remark "the sun has set" marks an advocate of the Ptolemaic thcor\' of astronomy. One may reply to this argument by carrying the illustration further. Surely, no Copcrniran, particularly in the days when the doctrine was still in (lisi)ute, would have claimed the right to describe astronomical phenomena in terms of the Ptolemaic theory. Similarly, the opponent of selfpsychology should describe the phenomena of consciousness without use of a term which, to say the least, predisjioses his reader to substitute for the conception of self as body, and of mind as sum of ideas, the conception, explicitly defied, of conscious self in relation to environment. The self-psychologist has then some right to urge that idea-psychologists are implicitly assuming or leading their readers to assume the existence of a self, when they describe consciousness in such words as "I attend to a color," "I perceive objects"; and still more when they mark off certain experiences as peculiarly personal; that is, as especially related to myself. ;
In addition to these cfytillenged implications of self, many uncompromising assertions/that psychology is science of the self may be found i\the writi/gs of contemi)orary psychologists, though they often substitute, fibr the word 'self,' some one of the expressions, subject, ego, miiHl, </ even soul. Thus, Professor Ward defines the standpoint of psychology as that 'of the living subject in intercourse with his special environment.' And Professor Judd says ex-
II. The Conception of the Object in Psychology
§ 2. The conception of object which this book sets forth is so likely to be misunderstood, that it will here be amplified. It should first be noted that the standpoint from which one speaks of objects of the self is, as James says, dualistic; but that it is psychologically, not ultimately, dualistic, so that the monist in philosophy may, as psychologist, unconcernedly adopt it. The basis of the conception is the fact that I always find myself conscious of an object: of myself or my experience, of other self or thing or relation. More fully stated: In being conscious, I am always conscious (even if vaguely conscious) of myself as related either to an object or to that totality of objects which I call my environment. Psychology, if it is to take account of the self, must, therefore, take account of the object. Indeed, all psychologists, whether or not they purport to study the self, really describe and classify consciousness with reference to objects. They classify attention, for example, as sensational or intellectual, according as one attends to sensational or to unsensational objects ; or they refer to color and to tone not only as sensations, but as existing outside eye or ear. This book follows Ward and James in the explicit recognition of the object of consciousness. In the words of the former: "Psychology deals with the subjective standpoint of individual experience, but we find that in this experience both subject and object are factors." * Or, to quote Professor Mitchell (who, however, for 'object' uses the word 'content'), " When conscious, I am always conscious of a definite something or other; and this is called the content of my experience or consciousness." f
* British Journal of Psychology (cited p. 283), I., i, p. 17. t " Structure and Growth of the Mind," Lecture I., § 3, p. 11. Mitchell defines ' object ' as content of knowledge or thought.
rcct uses of tlie term. The object of the psw hological self may take one of several forms, and cannot therefore he forthwith identified with any one of them. These forms, already enumerated,* are the following: (1) public objects of many or all selves whether (a) personal (that is, other selves) or (/>) impersonal, and in this ca.se, either external j)hysical objects, or non-external relations, laws, and the like; (2) private, or psychological, objects, either (a) myself, in relation to environment, or {h) my experiences. Our greatest danger is that of confusing the object, in the general and inclusive sense, with the public object — what Ward calls the cpistemological object . — and especially with the external object of the physical sciences. It is permissible, however, but only where no ambiguity thereby arises, to use the word ' object ' in what was perhaps its primary meaning, as indicating the 'otherthan-myself ' (that is, as including all forms of object except the private personal object), f and even to use the term, in either of the narrower senses, to mean ' public ' or ' external ' object.
A common confusion of the object with one special form of external object must be avoided with particular care. By the object of the self or of consciousness is never meant the stimulus, physical or physiological, of consciousness. The two are, indeed, to be contrasted sharply. When the object of my consciousness is, for example, the theatre curtain, the physical stimuli are ether vibrations, and the physiological excitations are obscure processes in retina and in brain of which I need never have heard and which, at best, I infer and do not perceive. In a word, the physical and physiological stimuli of consciousness are the phenomena of physical science, usually inferred, not perceived, whereas the object of consciousness is that of which I am conscious, without reference to which I cannot adequately describe my consciousness.
It has been pointed out in Chapter I. that important questions are raised by the conception of the ol)jcct of consciousness: a fundamental question about the identity of subject and object ; a second question about the alleged externality of objects of percep-
tion; and, we may licrc add, a sj^ccial problem about the precise nature of the objects of the rehitional consciousness. None of these questions, it must be reiterated, force themselves upon the psychologist so long as he holds steadily to his own business, the description and ex])lanation of consciousness, regarded as the relation of self to environment. The ])S3^chologist, in other words, assumes, on the testimony of his direct consciousness, that a self related to object exists. By reflection, he distinguishes different attitudes of self and different forms of the object. The ultimate nature of both he leaves to the philosopher to discuss.
OF Psychology
(a) On psychology as science of self, as science of ideas, as science of functions: (i) Summary: M. W. Calkins, Psychology: What is it About, Journal of Philosophy, Psychology, and Scientific Method, 1907, Vol. IV., pp. 673 ff. ; 1908, pp. 12 ff., 64 ff., 113 ff.
(2) On structural psychology : E. B. Titchener, The Postulates of a Structural Psychology, Philos. Reinew, 1898, VII., pp. 449 H.; A Textbook of Psychology, 1909, §§ 2-9. F. H. Bradley, A Defence of Phenomenalism in Psychology, Mind, 1900, N.S. IX., pp. 26 ff. H. Miinsterberg, Grundzuge der Psychologie, Kapitel II.
(3) On functional psychology: J. R. Angell, The Province of Functional Psychology, Psychol. Review, XIV., pp. 63 H. K. Stumpf, Erscheinungen und psychische Funktionen, 1907.
(4) For criticisms of self -psychology: W. B. Pillsbury, The Ego and Empirical Psychology, Philos. Review, XVI., pp. 387 ff, E. B. Titchener, ibid., 1906, XV., pp. 93 ff. M. F. Washburn, Journal of Philosophy, II., p. 716.
(5) On self -psychology : M. W. Calkins, An Introduction to Psychology, 1901, 1905, Der doppelte Standpunkt in der Psychologie, 1905; A Reconciliation between Structural and Functional Psychology, Psychol. Review, 1906, XIII., pp. 61 ff. ; Psychology: What is it About (cited above). W. Mitchell, Structure and Growth of the Mind, 1907, Lecture I.,esp. §§ 3, 5, 7. J. Rehmke, Lehrbuch der AUgemeinen Psychologie, Iter Teil, esp. §§ 11, 12. W. Stern, "Person und Sache, System der philosophischen Weltanschauung," I. J. Ward, On the
(b) On the conception of the object: Cf. Mitchell and Ward, cited above. Also, W. James, The Principles of Psychology, Vol. I., Chapter VIII., pp. 218 fT. ; Chapter IX., pp. 271 fT. IT. Miinsterberg, Grundziige der Psychologic, pp. 65 fF., esp. p. 72; and Psychotherapy, VI., pp. 130 (T.
(c) On parallelism in psychology: H. Ehbinghaus, Grundziige der Psychologic, 1902, I., §4, pp. 27 ff. (For the opposite view, cf. James, op. cit., I., Chapter V., esp. pp. 128-138. G. S. Stratton, Modified Causation for Psychology, Psychol. Bulletin, 1907, IV., 129 fT.
(d) For criticisms {mainly metaphysical) of the conception of consciousness : W. James, Does Consciousness Exist ? Journal of Philosophy, etc., I., pp. 477 ff. R. B. Perry, Conceptions and Misconceptions of Consciousness, Psychol. Review, XL, pp. 282 fT. F. J. E. Woodbridge, The Problem of Consciousness, Garman Commemorative Volume, pp. 137 fT. (Cf. Journal of Philosophy, 1907, IV., p. 677, for further references to James, Bawden, Montague; and for comments.)
Note on the ' reflective observation ' of perception and imagination {cf. Chapter II., p. 12). The discussion of perception introduces the important distinction between an immediate consciousness and the reflective observation of such a consciousness. Reflective observation is the after-consciousness of an earlier experience, the psychologist's awareness of an experience — his own or another's. To say that I am immediately conscious of the characters or relations which only afterreflection attributes to my experience is to commit what James calls the psychologist's fallacy. Yet, on the other hand, immediate and reflective observation may coincide. In any case, it is as allowable to classify an experience by taking account of the characters regularly attributed to it in after-reflection as to classify it by reference to physiological conditions.
Bibliography. — G. T. Fechner, Elementc der Psychophysik, i860, Bd. II., XLIV. F. Galton, Inquiries into Human Faculty. W. James, op. cit., Vol. II., Chapter XVIII. O. Kulpe, Outline of P.sychology, English translation, 1895, §§ 27, 28. W. Lay, Mental Imagery, Psychol. Review Monograph Supplement, 1898. G. H. Lewes, Principles of Success in Literature, Chapter III. J. Sully, The Human Mind, Vol. I., Chapter X. M. G. Caldwell, A Study of the Sense-Epithets of Shelley and Keats (Wellesley College Psychological Studies). Poet Lore, 1898, Vol. X., PP- 573 ff-
Standpoint
§ I. It is not the specific province of jjsychoUigy to study the human body, yet the psychologist must possess an acquaintance with the structure and functions of the body in order to explain and to classify those facts about the conscious self which are the proper objects of his investigation. A formal definition of 'the body' need not here be attempted. It may be described first in its relation to myself; second, in comparison with other objects. From the first point of view, my body is an ol)ject of which I am sensationally conscious; it is the object of which I am most persistently conscious; and it is, finally, a medium of relation between me and other external olijects. From the second standpoint, — that is, in com])arison with other objects, — the body is an organism, a sy.stematic- complex of structures and activities such that each is subordinated to the whole.
The function of the body as, so to speak, midterm between self and external things is due to two fundamental characters: it is readily affected by environing ol)jects and, in turn, it easily affects them. Though it consist, as in the case of the protozocin, of a single cell, that cell affects, and is affected by, its environment. The amoeba, for example, moves aside from an ol)stacle, attaches itself to a solid body, and unites these forms of reaction by [)rojecting ])arts of its body and closing them over food.*
But though all living cells are fundamentally alike in function, yet with the development of the animal body there goes on in the cells a progressive differentiation both in structure and in fimction. The changes of especial importance to the psychologist are the
286 Supplement to Chapter III.
following: Certain structures, known as sense-organs, situated for the most part on the bodil\' surfaces, become specially adapted to excitation by the environment; other organs, bones and muscles, take over the essential function of motor reaction to the environment; and connecting the two (though histologically closely related to the sense-organs) is the group of structures known as the nervous system.
I. THE MOTOR STRUCTURES OF THE BODY
§ 2. For the purposes of the psychologist it is sufficient merely to name the muscles, masses of contractile tissue, penetrated by blood-vessels, most of them ending in tendons, fibrous cords which are connected with the more than two hundred hones of the body. The bones, moving on each other at the joints, form a peculiarly flexible framework.
JSIotions of internal organs — for example, heart-beat and movements of the alimentary canal — are the contractions of the muscles composing these organs.
§ 3. From this reference to the specifically motor and the definitely sensor)^ organs of the body, we turn to the closer study of the structure connecting the two. Rudimentar}^ forms of such a connective system are found low in the biological scale, among the simpler (if not the simplest) of the metazoa. Beginning with the lowest of the vertebrates, we find the essential features of a cerebrospinal nen'ous system — a central system of nerve-centres connected on the one hand with all the sensory surfaces and, on the other hand, directly connected with all the skeletal muscles, and indirectly connected with the internal organs. (Besides the cerebro-spinal nervous system, the body contains both scattered 'sporadic ganglia,' and a number of nerv-e-centres, loosely united, the so-called 'sympathetic nerve system.' These centres, which are partly ' self-directing,' partly e.xcited through the central nervous system, control the activity of the internal organs, digestive, respiratory, and circulator}^)
§ 4. The cerel)n) sj^inal nervous system is made up of connected nerve-centres; and a nerve-centre is a tangled mass of neurones, or branching cells which are anatomically distinct. The structurally distinguishable parts of a typical neurone are the following:
Fig. 6. — Motor cell of gray matter of cord. From human fetus. The asterisk (*) marks the axone; the other branches are dendrites. From W. H. Howell, ".\ Te.xt-book of Physiology," Fig. 54 (after Lenhossek.)
(i) the cell-body, a bit of ])rotoplasm containing a nucleus; and (2) nenc-processes, prolonged from the cell-body, of two sorts, {a) the dendrites, broad in their origin from the cell-body and devious in their course, which give off intricately branching, 'antler-like' processes beginning near the cell-body, and (/») the axone, a narrow tibre, usually direct in its course. The axone is either a long
t'ibrc, enclosed in an albuminous covering (the medullary sheath), giving off few branches until it breaks up into a bunch of fibres at the end, or it is a short fibre "breaking up in a dendritic manner into a large number of fine branches." * As a whole, the neurone has been said to resemble "a bit of string frayed out at both ends and here and there along its course." f
Neurones are embedded in a spongy substance, called neuroglia. Masses in which cell-bodies predominate are called ganglia and are grayish in color, because the fibres which they contain are without medullary sheath. Masses in which nen^e fibres predominate are called 'nerves,' and look white. The nerve impulse is conducted, in the human body, at the rate of approximately t^t^ meters (loo feet) per second, by the nen^e fibres; it spreads from the terminal fibres of the axone of one neurone to the contiguous dendrites — ■ sometimes to the cell-body — of another. According to the direction in which the nerve impulse is conducted, nerves are distinguished as (i) afferent, or ingoing, nerves which convey inward the impulse communicated from some outer stimulus; and (2) efferent, or outgoing, nerves which convey the nerve excitation to a muscle. Midway between the two are found (3) the neurones of the nerve-centres of brain and spinal cord, whose function seems to be the redistribution, perhaps the modification, of the excitation conveyed by afferent nerves. Some psychologists hold that the function of redistribution belongs peculiarly to the cell-bodies.
I. The Spinal Cord
§ 5. Aside from the sympathetic system, there are two main groups of ner\'e-centres ; that is, of neurones massed together, those of spinal cord and of brain. The spinal cord, enclosed in its bony sheath of linked vertebrae, contains fibres which run (i) inward from the surface of trunk and of limbs, (2) outward, and (3) up and down
within the cord. The afTcrcnt (ingoing) filjres enter through the spinal ganglia, which lie inside the sjjinal column but outside the cord in the posterior nerve-roots. The efferent (outgoing) fibres are found in the anterior roots, some connect diflfcrent levels of the cord, while others connect the cord with the brain. The outer portion of the cord is made up mainly of axones each in its medullar}' sheath; the inner portion consists chiefly of cell-bodies and of dendrites, but contains also axones with and without medullary
mediately redistributed by the
spinal nerve-centres to an efferent nerve, or it may be transmitted along one of the upward fibres to a redistributing centre in the brain. The immediate spinal reaction is unaccompanied by consciousness, a fact established l)y the experimental observation that uncon-
scious movements of a limb, in
response to stimulation of the skin, occur after such injury to the spinal cord as prevents transmission of e.xcitation to the brain. The spinal cord is thus, first, a centre for unconscious reflex movements from cutaneous stimulation, and second, a transmitter of excitations to the brain. Many of the fibres running downward from the brain to the spinal cord cross from the right side of the brain to the left side of the cord (Figure 8) ; and consequently the stimulation of one side of tlie brain is followed by motion of the opposite side of the body.
Fig. 7. — ijcliL-niatic figure of the spinal cord. Posterior ganglion, x; affiTent nerve, y; efferent nerve, z. From W. H. HoweU, "A Te.xt-book of Physiologv," Fig. 62 (after
2. The Brain
§ 6. It is not possiljle to give an accurate verbal description of the brain; and its complicated structure can be fully understood only if one trace its development from the lowest vertebrate form. For the present purposes of psychology the student should familiar-
Fig. 8. — Schematic transverse section of the brain through the Rolandic region. S, Fissure of Sylvius; N.C. and N.L. (parts of a corpus striatum) and O.T. (optic thalamus), interior ganglia of the brain; C, one of the crura cerebri (bundles of up-and-down neurones); M, one side of the medulla oblongata; VII., the facial nerves. From James, "Psychology, Briefer Course," Fig. 43 (after Starr).
ize himself with diagrams, or })referably with models of the brain, and should distinguish between (i) lower brain (medulla, cerebellum, pons,, and crura, (2) interior brain (the basal nerve-centres enclosed within the hemispheres, N. C, N. L., and O. T. in
It is a moot question whether sense-consciousness accompanies the functioning of these lower and interior centres. The probability,* however, is that in the case of the lower vertebrates, with less develo])ed hemis])heres, the excitation of lower and of interior brain is accompanied by consciousness, and that, on the contrary, excitation of the hemispheres is necessary to human consciousness. It is certain that excitation of the hemispheres is the es* H. Donaldson, American Journal of Psychology, Vol. IV.
Fig. 9. — Schematic figure to illustrate reflex and ideo-motor movements. Adapted from W. James, "The Principles of Psychol-
sential ccrcliral condition of memory and of foresight. The l)odily movements characteristic of cerebral activity are, therefore, no longer the unconscious reflexes of the spinal cord nor even acts of which one has a bare sense-perception ; they are deliberative acts performed with a memory of past results and an image of future happenings. It follows that the response to a particular stimulation is not, as in the case of a spinal reflex, inevitable and determined. We may illustrate this by a diagram (Figure 9). The unconscious spinal reflex (a-b-f-g), following upon the touch of a hot surface, is the withdrawal of the hand. Suppose, however, that the stimulus conducted by the afferent nerve (a-h-r) is transmitted to the hemispheres instead of being at once redistributed in the spinal centres. The centre (e), corresponding with the sensation of warmth, is first stimulated, but the impulse is at once transrnitted to other brain-centres (y and x) and the total cortical excitation is accompanied by the conscious reflection that a hot application will cure neuralgic pain. The efferent nerve (d), which is finally stimulated, in turn excites a muscle whose contraction checks the instinctive movement away from the hot surface. Thus the motor response {d-h-i), to the excitation transmitted to the hemispheres, is a firmer grasp of the heated object, whereas the instinctive spinal reflex (a-b-f-g) would have consisted in the withdrawal of the hand. The following table summarizes these distinctions of bodily activity and consciousness as associated with different nen^e-centres : —
§ 7. It is possible to study, in even greater detail, the relation of the excitation of the cortex to different functions of consciousness. For this purpose, it is necessary to gain a clearer notion of the conformation of the hemispheres. It has been shown already that the immense expansion of each hemisphere results in a folding of its surface in upon itself. Each hemisphere thus consists of an irregular mass of folds, the convolutions, separated by deep gullies, the fissures. The most important of these appear'
very early in the growth of each embryonic hemisphere, on its outer surface. They are the fissure of Sylvius, which starts from a point below and in front of the middlqgjf each hemisphere (cf. Figure g), and runs backward, curving upward at its termination; and the fissure of Rolando, which runs downward and forward, from the median, ui)])cr part of each hemisphere (Figure 9) to a point near to that where the fissure of Sylvius begins. These fissures and others form the basis of the ordinary division of the hemisphere into five areas, or lobes. Roughly speaking, the frontal lobe lies forward of the fissure of Rolando and above the fissure of Sylvius; the parietal lobe lies back of the frontal, and also above the fissure
of Sylvius; the occipital lobe lies behind the parietal, and is separated from it by a fissure which appears most definitely on the median side of the hemisphere; and the temporal lobe lies below the fissure of Sylvius and forward of the occipital lobe. (The fifth lobe, the 'island of Reil,' is folded in within the temporal and the parietal lobes, and is not represented in the diagram.) On the median surface of the hemisphere (cf. Figure lo), it is important to distinguish, first, the triangular area of the occipital lobe, called
from its wedge shape the cuneus; second, the convolution along the upper edge, called 'marginal'; and finally, the curving convolution, called the iincinale (or hippocampus).
The study of cortical areas is important to the psychologist only for the following reason : investigation has shown that the excitation of certain parts of the corte.x is accompanied by definite forms of sense-consciousness and of bodily movement. There is much dispute, among the anatomists, about special features of cerebral localization, but the following results may be accepted as practically assured : —
its median surfaic known as tlio cuncus (Figure ii), is tlic cortical 'centre' of the visual perception of the different colors and hues, and is the centre, also, of movements of the eye-muscles.*
Fig. 12. — i'ijjures representing the probable location of the chief motor and sensory areas of the cerebral hemispheres in man. .4, outer surface. B, median surface. From W. H. Howell, "A Te.xt-book of Physiology," Fig. 82 (taken from E. A. Schafer, "Text-book of Physiology," Fig. 340).
with the left visual centre.
* Cf. Donaldson, American Journal uf Psychology, Vol. I\'., p. 121; Flcchsig, " Gchirn und Scelc," 2d edition, 1896, p. 77 ; Nagri, " Handbuch dcr Physiologic dcs Menschen," Bd. IV. i, i)p. 94 IT., csp. p. 99.
The area forward and hack of the fissure of Rolando is admitted to be a centre of bodily movements — of all movements of trunk and limbs, and of such movements of eyes, tongues, nostrils, and ears as are indirectly brought about Ijy mechanical stimuli. Many psychologists believe that the Rolandic area is the centre also of cutaneous sensation; but Schafcr, supported by some others, holds that the median gyrus fornicatus is the centre of cutaneous sensation and the direct centre of the movements initiated by cutaneous stimuli.*
The centre of hearing is the first temporal convolution; the cortical smell-centre, and possibly the taste-centre, are in the uncinate convolution of the median temporal lobe. These probably are centres also for such movements of ear, nostrils, and tongue as are directly due to stimulation of the end-organs of hearing, smell, and taste. The following summary of the sensory centres in the hemispheres combines these data: —
Of all muscles.
§ 8. It has been held by some psycliologists that an image is distinguished from a percept, not merely by the different degree and duration, but by the different locality of its cerebral excitation. Flechsig argues from the vagueness of some memory-images that they may occur when merely association-centres, not the sense-
centres, arc excited,* whereas the scnse-cenlrcs must, of course, be active in ])ercci)tion. James Ward Ijascs a similar argument on the case of patients who are able to recall familiar objects, but totally unable to recognize them when they are seen. He concludes that the centres for percept and for image must differ, however little, in locality. f But both these arguments are insufficient. The people who could recall and describe objects named to them may have had purely verbal images, and need not have visualized the objects at all. And every image, however 'vague,' contains sense-elements and must, therefore, be conditioned by the excitation of sense-centres. ft
§ g. The lowest form, biologically, of end-organ sensitive to light stimulus is a pigment-spot on the skin of an animal as far down in the scale as the volvox, an organism midway between unicellular and multicellular animals. § But there is nothing to show that the consciousness corres))onding to these stimuli differs from that which follows on mechanical stimulation. Next in the scale of light-adapted organs is the faceted eye, found in some Crustacea and in insects, familiar to us in the fly and in the bee. It consists in a large number of little cone-shai)ed organs, each of which transmits only the ray of light which passes directly through it; oblique rays are absorbed by the pigmented material with which these cones are surrounded. The result is a miniature 'sti])pled,' or mosaic, reproduction of the field of vision, since each of the thousand cones transmits light from one point only. A third type of eye, found also in insects, is the ocellus — a small eye, consisting
mainly of lens, retina, and rods, and of use, it is suy)[)Osed, in darkness and for near ohjects. 'I'liere is, tinally, the true eye, with its lens and its retina, found in crustaceans and in most vertebrates. § lo. The human eye has already been described, but in insufficient detail. It is a sphere, moved, in a bony cavity of the skull,
ment, whose forward portion is the iris (/) ; (3) the retina {R) which surrounds the posterior three-fourths of the eyeball. These membranes enclose three transparent bodies : the aqueous humor, a very fluid substance behind the cornea ; second, and most important to vision, the double-convex crystalline lens (L), enclosed in an elastic capsule attached (by a circular ligament) to the choroid coat; and finally, the vitreous humor (VH) a jellylike substance, full of floating particles, which occupies more than two-thirds of the cavity of the eyeball and "gives it substance." Together, aqueous humor, crystalline lens and vitreous humor form a double-convex lens.
TI1C eye is adapted by three sorts of muscular adjustment, for reaction to objects at ditTercnt distances: (1) Convergence and divergence are movements of the eyeballs, by the eye-muscles, which facilitate vision of near and far objects. When the eyeballs are parallel, clear images of indetuiitely distant objects, for exami)le of the stars, are formed. As the eyeballs converge more and more, that is, as the fronts of the eyeballs roll together and the backs roll apart, rays of light from every point of a nearer object are brought together at corresponding points on the retina^ of lioth eyes, so that the two eyes act as one.* (2) Accommodation is bodily process which changes the refractiveness of the lenses themselves. Accommodation is due to the contraction of the ciliary muscle (C.P)., "a muscle lying in the forward part of the choroid coat, outside the iris, composed in small part of circular fibres l)arallel to the circumference of the iris and in large part of fibres radiating from this edge of the iris." This muscle, contracting somewhat after the fashion in which a purse-string is pulled up, "draws the forward half of the choroid coat forward and inward, thus lessening the tension of the elastic capsule in which the cr}stalline lens is swung, and allowing the lens to bulge from front to back." t (3) The third of these muscular adjustments is the jHirely unconscious relle.x movement by whk4rthtrpTTpTr an opening in the iris of the eye, is enlarged or narrowed according to the distance of the object and the intensity of the light. There are great differences in these reflexes. The pupils of night-seeing animals — owls, for example — dilate far more widely in the night than the pu])ils of human eyes, and contract, in daylight, to a mere slit.
To sum up the main features of this description: The divergent rays from each point of a relatively near object are (i) brought together on the foveie of both eyes by convergence; are (2) bent more sharply by the bul<;in,<^ of the crj'Stalline lens through accommodation, and are (3) kept, by contraction of the pupil, from striking on the edges of the crystalline lens and producing chromatic effects.
Fig. 14. — Schematic diagram cf the structure of the human retina. From anterior (inside) to posterior (outside) of retina: I., Pigment layer; II., rod and cone layer; III., outer nuclear layer; IV., external ple.xiform layer; V., layer of horizontal cells; VI., layer of bipolar cells, inner nuclear; VII., layer of amacrucial cells (without axones); VIII., inner plexiform layer; IX., ganglion cell layer; X., nerve fibre layer. Adapted from VV. H. Howell, "A Text-book of Physiology," Fig. 143 (after Greefif).
and the structure of this innermost coat of the eyci)all must therefore be described in slightly more detail. It is composctl throughout most of its extent of ten layers; a layer of pigment cells (I); the layer (II) containing the minute transparent structures, rods and cones, which are the only j)arts of the retina directly affected by light; several interconnected layers of branching neurones; and the layer (X) formed by nerve-fibres ramifying in all directions from the oi)tic nerve {O.N . in Figure 13). This nerve pierces the sclerotic and choroid membranes from the rear; and the part of the retina at which it enters (displacing other retinal elements) is, as experiments show,* unaffected by the light. Outward from this 'blind spot,' in the centre of a colored yellow sjiot (the macula lulea), there is a little pit or depression {i\\Q. fovea, f.c.) in which the retina has thinned so that light more directly affects the cones, which here appear in unusual numbers with few or no rods among them. The retinal excitation is transmitted by the optic nerve, to the occipital lobe of the cortex ; and the following fact, already mentioned, concerning the correspondence of retina to brain-centres is important. When the branches of the optic nerve from right to left eyes meet (in what is called the optic chiasma), the fibres cross in such wise that fibres from the nasal side of the right retina and from the temporal side of the left retina are continued to the left brain hemisphere, whereas fibres from the tem])oral side of the right retina and from the nasal side of the left are continued to the right hemisphere. Thus, the two retina; — including the macul(c, or places of clearest vision — are represented in both hemispheres.
§ 12. To this account of the structure of the eye must be added a brief statement of certain theories of retinal process which differ from the hypothesis adopted in Cha])ter III. It must be borne in mind that these color theories are, one and all, hypothetical
descriptions of retinal processes which have so far eluded direct observation. Chronologically first is the theor)- indei)endently formulateil by Thomas Young and Hermann von Ilelmholtz. It holds that there are three retinal elements or processes whose excitation ct)nditions three color sensations — red, green, and violet. It explains sensations of colorless light as due simply to the combination in equal degrees of these three color-processes. Evidently this is a reasonable explanation of the cases in which a mixture of ether-waves of all lengths conditions the consciousness of colorless light. The Young-Helmholtz theory also explains, in the following manner, the excitation of colorless light sensations through the mixture of only two color-stimuli : ether vibrations of a given rate tend to set up in the retina not only the processes specifically corresponding with them, but also those which correspond with proximate vibration numbers. So blue light excites the retinal process which conditions the sensation-quality green, as well as that which accompanies blue; and yellow light stimulates the processes for red as well as for yellow. Therefore the combination of two complementary color-stimuli produces the same effect, physiologically, as the combination of all the color-stimuli. The specific physical condition of the sensation-qualities of colorless light is thus such a mixture of ether-waves as will stimulate simultaneously and nearly equally all physiological color-processes.
The conclusive objection, though not the only objection, to the Young-Helmholtz theory is the fact that it fails utterly to account for the four cases in which a sensation of colorless light follows upon a single color-stimulus. It is impossible to suppose that three color-processes are aroused when a single color-stimulus falls on the outer rim or on a small part of the retina, or when the colorstimulus is very faint. And, finally, the theorj' cannot possibly be reconciled with the facts of color-blindness. For in colorblindness one at least of the normal retinal processes is wanting, and there can therefore be no combination of three retinal processes.
A far more satisfactory explanation is that of Hering. He holds that a sensational consciousness of color is physiologically due to the activity of one of two antagonistic processes of an inferred
rt'tinal suhstaiuc. Oi theso substances, he l)elieves llial (here are two, each caj)able of an anal)olic, that is, assiniihitive or ' building up' process, and of a katal)oHc-, that is, destructive or 'tearing down' process. To tiiese four processes correspond tiie sensations of red, yellow, green, blue, whose exact relation may be seen by the following summar)' : —
1 Katabolic. Yellow.
So far Hering has explained simply our color sensations. To account for the colorless-light consciousness, he assumes another retinal substance with opposed ])rocesscs: —
An ecjuilibrium between the two processes occasions a sensation of middle gray ; and an unequal combination of the two processes excites sensations of light or dark gray. The white-black substance is excited by every light-stimulus, and is more widely spread than the color-substances over the surface of the retina.
With these presuppositions Hering explains as follows the various ways of e.xciting the consciousness of colorless light : When such consciousness is due to the combination of color-stimuli, antagonistic proce.s.ses in the color-substances destroy each other by simultaneous action, and the white-black substance remains in activity. When, for example, blue and yellow light fall simultaneously on the retina, the blue tends to set the blue-yellow substance into anabolic at tivity, whereas the yellow tends equally to stimulate the katabolic activity of the blue yellow substance. These opl)()site ])rocesses cancel each other; and ,so equilibrium is maintained and the blue-yellow substance, etjually stimulated in two
opposite directions, remains inactive, whereas the white-black substance, as has been said, is always active. Excitation by white light, that is, excitation by ether-waves of all lengths amounts to excitation through the combination of two pairs of complementary color-stimuli, red and green, blue and yellow, and results therefore in the inactivity of both color-substances.
In explanation of the colorless-light consciousness as conditioned by a single stimulus, Hering advances far beyond Helmholtz. He supposes (i) that sensations of colorless light arise w'hen small extents of the retina are excited by a single color-stimulus, because the stimulation of such small extents of the red-green or of the blue-yellow substance is not sufficient to rouse it to activity, whereas the ever active white-black substance is excited even by a colorstimulus; (2) that the excitations in faint light are not intense enough to affect a color-substance, but do excite the sensitive whiteblack substance; (3) that stimulation of the retinal periphery by color-stimuli excites sensations of colorless light, because only the white-black substance is found on the outer zones of the retina. Hering teaches finally (4) that a color-stimulus excites a sensation of colorless light when the subject is color-blind, because the retina of a color-blind person lacks one or both color-substances so that the color-stimulus affects only the easily excited white-black substance. Hering has certainly, therefore, furnished a plausible explanation for sensations of colorless light whether conditioned by a single stimulus or by a combination of stimuli. Grave objections have, however, been brought against the Hering theor}^ The most important of them may be briefly stated: (i) It is highly improbable that an assimilative bodily process should condition consciousness. (2) It is inconsistent to suppose that opposite color-processes, simultaneously excited, balance each other, and result in an absence of color-consciousness, whereas the opposite processes of the black-white substance, if excited together, occasion the consciousness of gray.* (3) As a matter of fact, a
mixture of red and green lights docs not, as Hering implies, occasion colorless-light sensation. On the contrary, the color-stimulus which, mixed with red light, produces a colorless-light sensation, is blue-green. This shows that the red and green which are psychically elemental are not physiologically antagonistic.
The theory set forth in Chapter III. is that of Mrs. C. L. Franklin, which is in agreement with that of von Kries in the fundamental teaching that the functioning of retinal rods has to do with the excitation of colorless-light sensations. In the opinion of the writer it meets the objections to the Helmholtz and to the Hering theories, and has also certain independent advantages. Three amplifications of our earlier statement of the Franklin theory should here be made.
§ 13. It should be stated first of all, in more detail, how on this theory the partial decomposition of the cone substance is brought about. Each molecule of the cone substance is, in fact, conceived as consisting of four parts, of which each is fitted to vibrate to one only of the color-stimuli — red, yellow, green, and blue light. Therefore a colored light is regarded as partially decomposing the cone substance by 'shaking out ' one of the atoms from each of its molecules.
It will be obsen^ed, also, that the von Kries and Franklin theories closely correspond with well-known facts concerning the distribution and the function of the retinal rods. For the rods, which (on this theor)') are organs of such colorless-light consciousness as is due to single stimulation, are found on the periphery of the outer zones of the retina, and are known by experimental observation to be readily affected in faint light. (Mrs. Franklin supposes that the visual purple, a retinal substance actually observed on the rods, reenforces faint light vision by absorbing a large amount of the light which usually passes entirely through the transparent rods and cones.)
§ 14. In the third place, these theories accord notably well with certain facts summarized under the name of the Purkinje phenomenon. These facts are the following: (i) Green and blue seen in faint light have a greater intensity than red and yellow.* On a
suiniiicr evening, for cxam])le, tlu' green of the marshes may be seen against the blue of the sea long after the goldenrod and tansy have lost their color and after the old red farm-house has turned gray. (2) If two grays — one j)roduced by the mixture of red and blue-green lights, the other by the mixture of blue and yellow lights — be precisely matched in a bright light, the first of the two will be seen as brighter than the other when both are observed in faint light. Both facts give support to the theory that the rods, and consequently the visual purple which lies on the rods, have to do with colorless light-vision. For all forms of the Purkinje phenomenon appear only in faint illumination, and the visual purple is active only in faint light; moreover, the Purkinje phenomenon consists in the intensification of green and secondarily of blue lights, and the visual purple absorbs green rays — and, after green, blue rays — most readily; finally, the Purkinje phenomenon, as has been found,* does not occur when the foveae of normal and partially color-blind eyes are excited; that is to say, it does not occur by excitation of the region of the retina which lacks visual purple and rods.
§ 15. The von Kries and Franklin theories, finally, offer a plausible explanation of color-blindness. The facts, though not undisputed, may be summarized as follows: There are two general classes of color-blindness, partial and total. Red-blindness (in which the spectrum order of colors appears as gray, yellow, blue) and green blindness (in which the order is yellow, gray, blue) are the most common form of dichromasia, or partial color-blindness; but there are also a few alleged cases of yellow-blue blindness, in which the patient sees grays, reds, and greens, but no blues and yellows. There are two forms of achromasia, or total colorblindness: in one, probably retinal in origin, the fovea is totally blind, and there are accompanying defects of vision ; in the second form of achromasia, very likely due to cerebral defects, the fovea is not totally blind, and there are no defects of vision other than
the color-hlindnoss. Tlu'sc facts ahsoluti-ly contradict the Helmholtz theorv ; are with dilTuuhy harmonized with the Hering theory ; supiHirt, or at least do not oppose, a theory of tiie fijencral type of the Frankhn liy])othesis.
The conformity of the I-'rankhn tiieor}' with these facts may best be shown by a somewhat more detailed discussion of red and green blindness. The red-green blind person has a normal vision of blue and of yellow, but confuses red and green objects with each other. Dalton, for exam])le, could not see his scarlet academic gown as it lay on the grass ; and another red-green blind man could not distinguish one branch, turned scarlet, of a maple tree from the rest of the tree which was still green. In these cases Hering assumed that both objects were seen as gray, and explained the color-blindness as due to the total lack in the retina of the green-red .substance and the ceaseless functioning of the w-hite-black sul)stance. But this explanation does not cover the distinction, e.x])erimentally discovered, between two sorts of red-green blindness. In that of the first ty])e, the red is matched with gray and the green with yellow ; for example, color-blind subjects examined by the Holmgren test, that is, recjuired to sort a lot of worsted skeins of different color and hue,* throw the unmixed red skein into the pile of the grays and the green into the pile of the yellows. In colorblindness of the second type, the red is matched with yellow and the green with gray. But according to the Hering theon*' there is no rea.son to suppose that, because the red-green substance is lacking from the retina, red or green light should affect the blueyellow substance. t The Franklin theory certainly has a negative advantage in that it does not meet this ditYiculty. Positively, it offers a plausible explanation of the two forms of red-green blindness by the teaching that color molecules in their primitive form contain two, not four, vibrating parts or atoms, one which e.xcites the sensation of blue and one which excites the sensation of yellow,
t More recently, Hering explains the distinctions in red-green blindness as due to individual difTerences in the macula lulea, or yellow spot. For comment on the inadequacy of this view, cf. C. L. Franklin, Psychological Review, VI., p. 82.
and that lliis yellow-exciting part is later diflferentiated into the jiarts which excite sensations of red and of green. This hypothesis exj)lains both the greater commonness of red-green blindness, since organs and functions latest accjuired are always first lost, and the tendency of red and green light to set in vibration the yellow-exciting atom.
Bibliography. — On color -theories: H. L. F. von Helmholtz, Handbuch dcr physiologischen Optik, 1896, esp. §§ 19, 20, 23. E. Hering, Zur Lehre vom Lichtsinne, 1874; and Grundziige der Lehre vom Lichtsinn, I. II., 1905, 1907. G. E. Miiller, Zur Psychophysik der Gesichtsempfindungen (reprint from Zeitschrift fiir Psycfiol. u. Physiol, der Sinnesorgane, 1897). C. L. Franklin, Mind, 1893, pp. 472 flf. ; The Functions of the Rods of the Retina, Psychol. Review, Vol. III., pp. 71 ff.; J. von Kries, Zeitschrift, IX., pp. 82 flF., and XV., pp. 247 ff. ; Abhandlungen, 1897; Die Gesichtsempfindungen, in Nagel's Handbuch der Physiologie des Menschen, Bd. III., pp. 109 ff. J. W. Baird, The Color Sensitivity of the Peripheral Retina, 1905.
§ 16. Brief reference has been made in the text of Chapter III. to the phenomena of color and light contrast. A little more must be said of simultaneous contrast. There are many everyday illustrations of it ; for example, the decided blue of the shadows on a sun-lighted field of snow. There are also many experimental verifications of the phenomenon.* The simplest is the examination of squares or rings of gray, on colored surfaces, through a tissue paper covering, which obscures the outline of the gray figures ; these gray figures will then appear in the color complementary to the background, yellow on a blue background, red on bluish green, and so on.
An exact explanation of this curious ])hcnomenon has never been given, but it has been established by Hering, against the teaching of Hclmholtz, that the explanation, whatever it is, of simultaneous contrast, must be physiological in its nature. Helmholtz taught that simultaneous contrast is no more nor less than a psychological illusion. According to his theory, we 'really' see, not a complementary contrast-color, but the physically e.xcited, actual gray figure, though we fallaciously suppose that this gray is yellow, if it lies on a blue background, or green, if it is seen against purple. The cx])lanation, for so wides[)read an illusion, is found in the admitted fact that people are accustomed to look at familiar, colored objects through a complementary colored medium which makes them seem gray. For example, we see a red brick wall through the green lights of a hall door; the wall seems gray, but w'e still think of it as red. Or again, the blue gown looks gray in the yellow gaslight, but is known to be blue. The gray figures of the simultaneous contrast experiences are thus, Helmholtz holds, inferred — not actually seen — to be of a color complementary to that of the background. But opposed to this theory of Helmholtz are insurmountable obstacles- In the first place, it directly contradicts our introspection. We not only do not naturally see objects, in simultaneous contrast, as gray, but in most cases we cannot force ourselves to do so; the gray ring on the colored background is immediately, and inevitably, blue or yellow or red. It is highly im])robable, in the second place, that our comparatively infrequent and unnoticed experiences of colored objects, in light of a complementary color, should have formed in us such a habit of inference as this theory supposes. The Helmholtz theory is disproved, finally, by direct and unambiguous experiments.*
It is fair to conclude, with Hering, that simultaneous contrast is physiologically conditioned ; in other words, that when one part of the retina is directly excited by a colored light, retinal processes which condition a complementary color are set up in the neighboring retinal regions. This undoubted fact can be stated in terms
On simultaneous contrast: H. von Helmholtz, Handbuch der Physiologischen Optik, 2te Aufl., § 24. E. Hering, Beitrag zur Lehre vom Simultan-Kontrast, Zeitschr. J. Psych, u. Physiol, d. Sinncsorgane, I., 18. C. L. Franklin, in Mind, N.S., II., 1893.
Fig. 15. — Semi-diagrammatic section through the right ear. B, one semicircular canal; 5, cochlea; Vt, Scala vestihuli ; Ft, Scala lympani. For meaning of other symbols, see text. From H. N. Martin, "The Human Body," Fig. 143 (after Czermak).
varied in length. These structures are found in certain of the lower invertebrates — for example, in jellyfish, in Crustacea, and, in insects — and in the lower vertebrates. It is probable, however, or at least very possible, that these are organs not of hearing, but of pressure consciousness, and that the sensations which accompany the excitation of these organs do not qualitatively differ from sensations due to mechanical stimulation. The vibration of air or water striking on these organs then acts merely as a jgr: It will appear that one part of the human ear has probably the same function.
§ 18. The human ear has three rudely distinguished divisions: the outer ear, inner ear, and middle ear. The outer ear consists in the pinna or concha {M) opening into a hollow tube, the external meatus (G) ; and this tube is closed by a surface, the tympanic membrane {T). This is thrown into vibration by the motion of air-particles, and its motion is transmitted to a series of three bones, called, from their shape, malleus, incus, and stapes (that is, hammer, anvil, and stirrup). These bones lie within the drum or middle ear (P), a hollow in the temporal bone from which the Eustachian tube (R) leads downward to the pharynx. The middle ear communicates by two foramina, or windows, with tin- inner car, a complex bony tube embedded in the sjjongy part of the temporal bone of the skull. The inner ear has three main divisions, and these must be described in some detail. They are (i) a middle chamber, the vestibule (F), which is an irregularly rounded envelope containing two small membranous bags, or sacs, the saccule and thf utricle; (2) the three semicircular canals, at right angles to each other — one horizontal, one running forward and back, one running right to left, all of them oi)ening into the utricle.
the semicircular canals (to the right of the diagram). Utri^-le, It; saccule, s; cochlea, c. From J. R. Angell "Psychology," Fig. 44 (after McKcndrick and Snod-
Each bony canal contains a membranous tube, of the same general shape yet more nearly completing a circle, and each tube ends in a dilation, or ampulla, opening into the vestibule. Each sac of the
Fig. 17. — A transverse section of a circle of the cochlea. Org. C, organ of Corti; m.t., tectorial membrane. For meaning of other sjTabols, see text. From M. Foster, "A Textbook of Physiology," Fig. 180.
vestibule and each membranous canal is surrounded by a liquid, the perilymph, and.filled with a liquid, the endolymph. A branch of the auditory nerve penetrates each of these ampullae and the vestibule as well, ending in cells from which hairs project; and in
the vestibule, at least, there arc small, hard substances, the ear stones, or otoliths. The essential feature of the apparatus is its extreme sensitiveness to changes of bodily position. The slightest movement which tends to unbalance the body must alter the position of the semicircular canals, and thus put in motion the endolymph. This movement, with or without the additional pressure of an otolith, bends the hairs of the ampulhc and stimulates the vestibular section of the acoustic nerve, and this excitation reaches the cerebellum, which is the subcortial nerve-centre for the movements affecting bodily equilibrium. Actual experiments show the connection of these organs with the preservation of balance. Animals deprived either of cerebellum or of semicircular canals stagger and fall about in an unbalanced and helpless way; and deaf people whose semicircular canals are injured cannot preserve their equilibrium if they are blindfolded and therefore unable to regulate their movements by the visual perceptions of bodily positionAs so far described, the ear, like the otocyst, seems an organ adapted rather for excitation of pressure sensations, due to change of position, than for the excitation of the auditory consciousness. Auditory consciousness results, in all probability, from processes excited in (3) the cochlea, a bony spiral of two and one-half coils around an axis. From this axis projects a bony shelf, the lamina spiralis (Layn. sp. in Figure 17), which ends in the basilar membrane {m.h.). Together, bone and membrane divide each spiral into two winding half-coils, the scala tympani (Sc.T.) and the scala vestibidi {Sc.V.). The former opens by the round foramen into the middle ear; the latter is connected with the vestibule. Each contains a liquid, the perilymph. A third division, the cochlear canal, or scala media (C.Chl.), is partitioned off by a membrane (m.R.) from the scala vestibnli. The. cochlear canal forms the membranous cochlea and contains a liquid, the endolymph, whose vibrations, as will appear, excite the auditory end-organs. § 19. The basilar membrane consists of cross-fibres, radially stretched strings varying in length from bottom to top, base to apex, of the cochlea — the longest strings near the top, where the lamina spiralis, or bony side of the partition, is narrower. Some of
these fibres support the inner and the outer rods of Corti, which number respectively about six thousand and about four thousand. These are tiny membranous rods increasing in size from base to apex of the cochlea and leaned against each other to form an arch. The cochlear branch of the auditory nerve runs through
Fig. i8. — Diagrammatic view of the organ of Corti and the accessory structures. A, inner rods of Corti; B, outer rods of Corti; C, tunnel of Corti; D, basilar membrane; E, single row of inner hair cells; 6 ,6', 6", rows of outer hair cells; 7, 7', supporting cells of Deiters. (There are supporting cells beneath the inner hair cells, also.) The hairs of the inner cells are seen projecting through the meshes of the reticulate membrane. From W. H. Howell, " A Text-book of Physiology," Fig. 162 (after Testut).
the whole length of the lamina spiralis, and terminates in hair-cells which lean against the rods of Corti. Hairlike filaments grow upward from these cells.* Just above, and apparently projecting from the edge of the lamina spiralis, is another delicate membrane, the tectorial membrane {m.t., in Fig. 17).!
* These 'hairs' extend through minute openings in a thin membrane, the reticulate membrane (/?) which extends in both directions from the summit of the arch formed by the rods of Corti.
It is iiiii)ossible to state with certainty the function of all these structures in hearing. It used to be thought that the rods of Corti ]ilay the i)art in our ears of strings in a piano, vibrating because of their differing length and span with air-waves of different rates. Several arguments, however, tell strongly against this view. The rods are neither sufficient in number, nor sufficiently varied in size, to serve this jjurpose; they are not found in the auditory endorgans of birds whose ability to discriminate pitches can hardly l)e doubted; and finally, they are not directly connected with the fibres of the auditory nen'e, which terminate, as has been said, in the hair-cells of the basilar membrane. The following is a more probable, though by no means a definitely justified, account of the function of these structures. It is based on the general assumptions of the Helmholtz theory : When certain fil)res of the basilar membrane are thrown into sym])athetic vii^ration, the rods of Corti are moved U])ward, and with them hair-cells lying on their sides. The filaments projecting from these hair-cells are, thus, pushed against the tectorial membrane and the downward reaction from this contact excites the auditory nerve-endings in the hair-cells.
§ 20. A noticeable feature of the auditory consciousness excited by the simultaneous vibration of two sounding bodies is the occurrence of beats, swift and regular alternations of loud and weak sound. Beats are occasioned by a combination of pendular airwaves whose vibration numbers are near each other. Such airwaves "reenforce the vibration of air particles which they affect so long as their phases are alike," Init when one of these air-waves by itself would set the air particle vibrating in one direction while the other would affect the air particle in the opposite way, the two counteract each other; and at a given moment the air particle will be held in equilibrium so that it will not vibrate at all. Professor Myers distinguishes "four stages" in the beating of two tones
according as a tone of, say, 256 viljrations beats (i) with a tone of fewer than 264 vibrations, (2) with a tone of 264 to 284 vibrations, (3) with a tone of 284 to about 300 vibrations, and (4) with a still higher tone. "In the first stage," he says, the beats "have a surging, in the second a thrusting, and in the third a rattling character; finally they fuse and pass into a stage where only roughness remains, beyond which they completely disappear."* Helmholtz attributed disagreeable auditory combinations of pitch, or dissonances, to the occurrence of beats.
Simultaneous pendular vibrations, not too closely alike, produce so-called combination tones of two sorts — difference tones and summation tones. In the first case, the attentive listener hears not merely two fundamental tones, but a sound whose vibration number equals their difference, sometimes also a second difference tone whose vibration number is the difference between the lower primary and the first difference tone, and sometimes even lower difference tones. In the second case, but with more difficulty, the practised listener hears a sound whose vibration number is the sum of the two fundamentals. Combination tones are sometimes 'objective'; that is, they are due to external air- waves, but more often they are ' subjective,' that is, due to conditions within the ear. Indeed, difference tones must always be in this sense subjective, unless produced by some secondary vibration of the sounding body. It is likely that combination tones are due to the vibrations of the tympanic membrane — perhaps also to the vibrations of the membrane of the fenestra rotunda. f
§ 21. Certain alternatives proposed by contemporary psychologists to the Helmholtz theory should briefly be named. In criticism of the theory it is urged, first, that the basilar meml^rane fibres are not capable of vibrating so freely as the theory requires; and
second, that their variations in lengtii — only 0.04 to 0.49 between tlie longest and the shortest of the 24,000 fibres — is too slight to permit vibrations ranging from 15 to more than 20,000 ])er second. In lieu of the Helmholtz hypothesis, and to avoid these diiTicultics, the following theories, among others, have been advanced: —
(i) The hypothesis of Rutherford (the so-called telephone theory) regards the cochlea merely as a transmitting instrument, and holds that the sjiecial characters of a sound sensation have jjurcly cerebral explanation.
(2) The theory of Kwald is based on experiments with elastic membranes, some of them of minute size and of great delicacy. Ewald found that such a membrane vibrates throughout its length at each stimulation and that, examined under a microscope, it presents the picture of a series of waves, visible as 'dark, transverse streaks.' These sound-pictures, as Ew^ald calls them, vary, that is, the crests of the waves vary in their interval for each tone; and Ewald supposes that, at these intervals, hair-cells and nervefibres are stimulated.
(3) The theory of Max Meyer is not easily stated in abbreviated form. He supposes that successive sound waves, of a given vibration number, travelling up the scala vestibuli, press down the basilar membrane, and that pitch is due to the number per second of these downward pressures, and loudness to the extent of basilar membrane, and thus to the number of nerve terminations, excited.
The first of these theories is rather a confession of ignorance than a positive hypothesis. The objection to them all is that they fail to take account of the very elaborate dilTerentiation of structures in the organ of Corti.* Yet both the Ewald and the Meyer hypotheses are worthy of further study.
Bibliography. — On theories of hearing: Rutherford, Rcjwrt to British A.ssociation for the Advancement of Science, 1886. K. Ewald, Zur Physiologic des Labyrinths, Archivfiir die gesammte Physiol., 1899, LXXvi., pp. 147 ff.; 1903, XCIII., pp. 4S5 ff. Max Meyer, An Introduction to the Mechanics of the Inner Ear, Utiiv. of Missouri Studies,
Scicntijk Scries, up-j, 11., i (cf. Zrilsriiri/l, 1898, X\'I.). H. L. F. von Hclmholtz, Sensations of Tone, transl. by A. J. Ellis, 1895. C. Stumpf, Tonpsychologie, Bd. I., 1883, Bd. II., 1890. K. L. Schafer, Der Gehorsinn, in Nagel's Handbuch der Physiologic der Menschen, Bd. III. ; J. G. M'Kcndrick, in E. A. Schafcr's Text -book of Physiology, Vol. II., pp. 1 1 79 tT.
§ 22. The hypothesis that there are as many elemental qualities of pitch as there are distinguishable qualities in an octave is suggested by McDougall, and supported by the following considerations: "(i) The ^analogy of the other senses, in which . . . the elementary qualities are few, renders improbable the assumption of a very large number in the case of hearing. (2) We know that it is impossible for some ears to analyze complex tones or clangs which are easily analyzed by others, and that even a well-trained ear may find difficulty in analyzing the complex form of a tone and its octave or first overtone. (3) Pure tones are not merely more or less different in pitch; some that are of very different pitches have nevertheless a great resemblance; . . . The first overtone or octave of any tone differs from it, as regards pitch, more than any of the intermediate tones of the scale, and yet is, in another indefinable fashion, more like it, so much like it that even a trained ear may mistake a tone for its first overtone. This fact suggests that each pure tone is a fusion of at least two elementary qualities, one of which is common to it and all its upper and lower octaves, another which is peculiar to it and . . . constitutes its pitch. (4) If each distinguishable tone were an elementary^ quality, we should expect to find that when the air is made to vibrate at a steadily increasing rate, as when a violinist runs his finger up the bowed string . . . the pitch would rise by a series of steps from one elementary quality to another; but this is not the case; the transition is perfectly smooth and continuous. . . . We are therefore driven to believe that the so-called simple tones are . . . complexes, and we have no certain guidance as to the number of elementary qualities by the fusions of which all the tones are pro-
iluccd. . . . PtThaps thr most satisfactory view, if the physical mechanism of the internal ear t an be shown to admit of its adoption, is that all the elementary (lualities are contained in a single octave, which might he likened to the complete color-series, and that the differences of pitch that distinguish the same (|ualitics in different octaves are not properly differences of quality, depending upon specific differences of the psycho-physical processes, but are rather of the same order as differences of extensity or voluminousncss in the case of visual, tactual, or temperature sensations, and are due to differences in the number of sensory neurones excited, the deep pitch (the voluminous) being due to simultaneous stimulation of many neurones, high pitch to stimulation of few."* 'J1ie physiological assumjition of this theory is not, on a priori grounds, incompatible with any one of the theories of tone.
§ 23. Evidently, the ability to respond to the chemical stimulus of food is at least as potent a factor in the preservation and development of animal life as the sensitiveness to mechanical stimulation from external objects. As a matter of fact, certain unicellular animals, amoebae and many metazoa of simple form, respond by a special reaction to chemical stimulation. A hydra, for example, always avoids mechanical objects, but seizes on food with its tentacles. t We must guard ourselves, however, from attributing either taste or smell, as we know them, to animals who have no trace of distinct taste and smell end-organs and who give no evidence of reacting in different fashion to liquid and to gaseous stimulus. Such differentiated organs and reactions are not found in animals lower in the scale than insects, and are lacking in many of the lower vertebrates. ff The comparative psychologists give the name 'chemical sensations' to the simple consciousness which may be supposed to accompany the undifferentiated reactions to chemical stimuli.
§ 24. In the human body the end-organs l)oth of smell and of taste are structurally similar to those of contact, though they occur neither on the outer or joint surfaces nor in the muscles, but in the epithelial linings of nose and throat cavities. The end-organs of smell are situated in the upper part of the nose. The nasal
Two facts experimentally observed seem to show that the endorgans of smell are of differentiated structure, and thus fitted to respond, some to one olfactory stimulus, some to another. These * For experiment, cf. Sanford, 57, 58; Titchener, § 28.
Fig. 19. — Schematic fi.^ure of the interior of the left nostril. .5' represents the septum, or partition between the nostrils as artificially turned upward. The shaded portion represents the olfactory membrane. Yron-i W. Nagel, "Handbuch der Physiologic des Menschen " Fig. 106 (after V. Brunn, taken from Zwaardemaker," Physiologic des Geruchs.")
facts arc (i) ])artial anosmia, or ))crmancnt insensibility to some smells, not to all. an infre(|uent hut well-cstahlishetl experience; and (2) the normal etTect of fatigue. A person, for exami)le, whose end-organs of smell have been fatigued by continuously smelling camphor, can smell creosote as well as ever, almond but faintly, and turpentine not at all. If smell end-organs were of one type only, all would be alike fatigued, and complete insensibility would be the result.* We have, however, no list of elemental smell cjualities by which to test in an exact way the differentiation of smell end-organs. Zwaardemaker has, to be sure, proposed a classification on the basis of that of Linnaais, into ethereal, aromatic, balsamic, amber-musk, alliaceous, burning, hircine, repulsive, and nauseating smells. f Obviously, however, this is no list of elemental qualities, but an empirical grouping of complex odors.
The olfactory nerve leads from the smell end-organs in the peak of the nostril to the olfactory lobe, originally a projection from the hemispheres, but, in the adult brain, lying on the lower surface of the frontal lobe. From the' olfactory lol)e, nerve-libres lead to the median surface of the temporal lobe. The olfactory lobes and tracts are much more developed in other vertebrate brains than in the human brain: and it will be remembered that the sense of smell,- in the higher vertebrate animals, though perhaps less differentiated, is far keener than ours.
$25. The end-organs of taste are situated near the entrance to the alimentary canal, within the papillae or folds formed by the membranous covering of the tongue and the forward part of the palate. Two kinds of papilla; have to do with taste excitation: large circumvallate papillae, like castles surrounded by moats, found mainly near the root of the tongue; and elongated fungiform papillae, visiljle as red dots on the forward and middle part of the tongue. All the circumvallate papillae and some of the fungiform j)apill;v carry taste-buds, minute globular bodies containing
Fig. 20. — Section through the circumvallate papilla of a calf, greatly enlarged. Taste-bud, a; nerve-endings, />. From Th. W. Englcmann, Fig. 270, in Strieker, " Lehre von den Geweben," Bd. II.
In children, all parts of the tongue and even the mucous membrane linings of the cheeks are sensitive to taste stimulation; in adults, the cheek linings and the middle part of the tongue are completely insensitive. Different parts of the tongue are sensitive to different stimuli — in general, the back of the tongue to bitter, the tip to sweet, and the borders of the middle part to sour, The insensitive areas dififer for different stimuli as the accompanying figure representing the work of one investigator indicates. It
* Excitations of the taste end-organs are carried to the hemispheres from the back part of the tongue and from the throat by the glosso-pharyngeal nerve; from the forward two-thirds of the tongue by the lingual part of the fifth and by the seventh nerve. (For discussion of the respective functions of the lingual and the seventh nerves, cf. Howell, "Text-book of Physiology," p. 270; Nagel, in " Handbuch der Physiologie der Menschen," III., pp. 624 flf. ; and Foster, "A Text-book of Physiology," one-volume edition, 1895, p. 1036.)
the median temporal lobe.
Bibliography. — On scnsalions of smell: Zwaardemaker, Die Physiologic des Geruchs, Fig. 21. — Schematic iSg5. W. Nagel, Der Geruch.sinn, in Nagel's diagram of the surface of
above), Bd. III. F. Kicsow, Beitriigc zur physiologischcn Psychologie des Geschmacksinnes, Wundt's Philosophischc Studicn, X. and XII. C. S. Myers, The Taste-names of Primitive People, British Journal of Psychology, 1904, I., pp. 117 fif. ; G. T. W. Patrick, American Journal of Psychology, 1899, pp. 160 ff. H. Zwaardemaker, Geschmack, in K. .\shcr und Spiro's Ergebnisse der Physiologie, II., ii., 1903.
Fig. 22. — Semi-schematic section of the skin of the pulp of the fingers. Sp, papillary layer of the skin ; Sr, reticular layer of the skin ; za, fat ; cM, Meissner's corpuscles ; cP, transverse sections of Pacinian corpuscles ; ON, RufiSni's endings; At, arteriole; gs, sudoriparous glands. From L. F. Barker, "The Nervous System and its Constituent Neurones," Fig. 245 (after Ruffini).
have been (lovclo])cd from dilTcrentiated structures in the skin. The uncritical observer thinks of the skin as 'organ' of contact, of temperature, and of pain sensations ; but the skin — besides serving as excretory organ — merely contains and jjrotccts the minute organs affected by the external physical stimulus. The most important of these organs are: (i) Hair-bulbs, from which |)roject the fine hairs which transmit any movement with accelerated force. (2) Tactile corpuscles (Meissner's), found chiefly in the jiapilkT of the dermis of hand and of foot. (3) Touch cells (Merkcl's) 'of the same essential structure,' but receiving only one nerve-fibre each, distributed all over the skin. (4) Pacinian corpuscles widely distributed in the skin, the periosteum of the bone, the covering of the viscera, the muscles, and the tendons. (4) Articular end-bulbs, found on joint surfaces. (5) The so-called end-bulbs of Krause, found in tendons, cross-striated muscles, outer skin, cornea, and lining of the mouth. (6) The endings of Ruftini, cylindrically shaped, deep-lying bodies.
cells and the Meissner corpuscles are organs of pressure sensation due to stimulation of the skin. For the hairy parts of the skin are especially sensitive to pressure; and one or more pressure spots are almost always found near the place where each hair leaves the skin. On the hairless surfaces (which however are few and of small extent) the cori)uscles of Aleissner correspond fairly well in number with the actually discovered pressure-spots. Furthermore, with the exception of the hair-cells and the Meissner corjuiscles, no end-organs occur in numbers at all e(jual to lhu:>c of the pressure-spots of any given locality.
There is less certainty concerning the end-organs of pain, cold, and warmth. Von Frey teaches that the end-organs of cutaneous pain sensation are the so-called 'free' nerve-endings — that is to say, the endings of nerves without differentiated terminal organs — in the epidermis, or bloodless upper layer of the skin.* He reaches this conclusion on the ground that the relation of weight of stimulus to intensity of sensation proves that the pain endorgans lie above the pressure organs, a condition fulfilled by the free ncn-e-endings only.* An apparent objection to this theory is the fact that pain, with end-organs nearer the surface, is less easily excited than pressure. This difficulty is met by the supposition that, in the case of stimuli of moderate intensity and duration, the inelastic epidermis, in which are the free nerve-endings, simply transmits the stimulus to the lower-lying cutis, in which are the pressure organs. The fact that the warmth spots on the skin are so much less easily determined than the cold spots suggests the possible identification of organs of cold with the 'end-bulbs of Krause ' and of warmth organs with the deeper-lying ' endings of Ruffini.' The excitation of cold spots by a stimulus above 45° centigrade gives the so-called 'paradoxical sensation' of cold.
Comparing the sensitive spots of the skin — the pressure spots, pain spots, warmth and cold spots which cover end-organs of these various sorts — we reach the following results : In spite of the differences in distribution, already noted, f the greater part of the skin may be said to contain pressure, pain, cold, and warmth spots. The pain spots are most frequent, though pain is less easily excited than pressure sensation. There are on the average at least 100 pain spots, J 25 pressure spots, 12 cold spots, and 2 warmth spots on a square centimeter of the skin. All the endorgans, except those of pain, seem to become adapted to longcontinued stimulation : for example, we no longer notice the warmth
inattentive to it.
It should he added that recent exjjeriments point to the existence of a second, previously undiscovered, cutaneous sensory apparatus. Phenomena which attend the healing, after cutting, of afferent cutaneous nerves indicate that accurately localized sensations (of light contact and of moderate cold and warmth, not of pain) occur indejiendently of the sensations due to excitation of the end-organs just described.*
§ 28. Tn addition to the sense-organs in the skin, end-organs differing from these in external form which are yet (in all probability) modifications of essentially similar endings are found in the muscles and joints. These deeper-lying end-organs condition sensations of which the greater number, at least, seem to be of the same nature as cutaneous sensations: pressure, cold, warmth, and pain. Among these dcc[)er-lying organs arc the Pacinian corpuscles in the muscles and joints, to whose excitation are due the sensations, probably of pressure, following on the independent stimulation of muscle and of joint. f Strain-sensation, due to excitation of the tendons, very likely has as end-organs the socalled 'spindles of Golgi.'
Some psychologists have attributed to subcutaneous end-organs what they regard as the sensational consciousness of bodily position and of bodily movement — so-called ' static ' | and ' kinaesthetic '
* Cf. Head, Rivers, and Shcricn, Rivers, Rivers and Head, and Franz, cited on p. 328 below. This newly discovered 'epicritic' sensory mechanism is distinguished from the ordinary 'protopathic' system (with its nerves ending in the terminal end-organs) in that excitation of this 'epicritic' system is not punctiform. In other words, not specific areas of the skin but the whole surface seems sensitive to light contact, cold, and warmth. Furthermore the sensations due to excitation of the epicritic .system (not those duo to excitation of the protopathic apparatus) may be graded in intensity.
sensation. In the opinion of the writer of this book these are, however, complex not simple experiences, perceptions not sensations. According to this view, the perception of bodily position includes along with pressure sensations due to supporting objects — chair, couch, or floor — a visual consciousness, perceptual or imagined, of the body. Where this visual consciousness is lacking, as when one wakes suddenly, there is a loss of consciousness of position. Similarly the consciousness of movement of the body is made up of the pressure consciousness due somewhat to muscular contraction but mainly to the movement of joint-surfaces on each other and supplemented by the visual consciousness of the body in successive positions.
Bibliography. — On cutaneous sensations: Max von Frey: Beitrage zur Sinnesphysiologie der Haut, Berichte der Geseltsch. d. Sdclis. Ges. d. A. Goldscheider, Gesammelte Abhandlungen, I., 1898. C. S. Sherrington, in Schafer's Text-book of Physiology, II., pp. 920 ff. T. Thunberg, Physiologie der Druck, Temperatur und Schmerzempfindungen, in Nagel's Handbuch, 1905, III., 647 ff.
On sensations fotlowing nerve-division: Head, Rivers, and Sherren, The Afferent Nervous System from a New Aspect, Brain, 1905, XXVIII., pp. 99 ff. ; Rivers, Psychot. Bulletin, 1908, V., pp. 48-49. Rivers and Head, A Human Experiment in Nerve-division, Brain, 1908, XXXI., pp. 323 ff. 8. I. Franz, Sensations following Nerve-division, Journal of Comp. Neurology, 1909, XIX., 107-123, 216-235.
as a further unanalyzablc result of a structural * analysis of consciousness — a distinguishable, though never separate, constituent of experience. Other criteria which have been proposed are 'independent variation' (cf. M. F. Washburn cited below) and abscjlute, atomic distinctness (cf. H. Miinsterberg, " Grundzuge der Psychologic," Kap. XV., sec. 4). For defence of the conception of qualities, intensities, and extensities as 'attributes' of the sensation, regarded as element, cf. E. B. Talbot, Philos. Review, 1895, IV., pp. 154 ff. ; for summary, cf. M. F. Washburn, Philos. Review, 1902, XI., pp. 445 flf.
§ 30. The conception of sensational intensity and extensity as elements of consciousness has been opposed on the ground that no physical and physiological conditions of intensity and extensity can be assigned. For detailed consideration of this objection, cf. Psychological Review, 1899, pp. 506 flf.
§ 31. Within the class of sensational elements, psychological method recognizes three subclasses, usually distinguished as qualities, intensities, and extensities. The fundamental ground for this division is the observed distinctness of these groups of elements, the fact that the experiences of hue, of j)itch, and of taste seem, from one point of view, to belong together, and to be equally distinct from the experiences of brightness, of loudness, and of taste intensity, or from the consciousness of visual and auditory bigness. The experiences of intensity and of extensity are further distinguished on the ground of their capacity for being ordered in direct and .simple sensational series. For amplification of this distinction, cf. the writer's " An Introduction to Psychology," f second edition, 1905, [)p. 43 ff., 105 ff., with citation, and MiinI sterberg, "Grundzuge," Kap. VIII., pp. 276 ff., 283 ff.
§ 32. For further discussion of sensational extensity, cf. Chapter IV., pp. 66 ff., and Appendix, Section IV., § 2, pp. 333 ff. For emphasis on the distinction between the elemental experience of extensity, or bigness, and the complex consciousness of position, ff. pp. 67 ff. It is still a moot question, even among f)sychologists who admit the elemental nature of visual and pressure extensity,
accompanying sounds, tastes, and other sensational qualities.
§ 2,T,. Duration is often named along with quality, intensity, and extensity as a sensational element (or, when the older terminology is adopted, as 'attribute of sensation'). But the consciousness of duration, when it occurs, is a complex, not an elemental, experience; and it does not even form a part of all sensational experience. For defence of this view, cf. M. W. Calkins, Psychol. Review, 1899, VI., p. 510, and "An Introduction to Psychology," second edition, p. 491, and M. F. Washburn, Psychol. Review, 1903, X., pp. 416 ff.
§ 34. This book recognizes three sorts of elemental experience : sensational, attributive, relational. These classes are distinguished as follows. Sensational elements seem to be present in every conscious experience. However abstract a thought or however impassioned an emotion, always it seems to include sensational elements, the consciousness, for example, of warmth or of cold, of quickened or of retarded breathing.* Corresponding with every sensational element, there is some assignable change, both in an area of the brain-cortex and in a peripheral nerve end-organ. For almost every sensational element there is a distinct physical condition. Thus, the rate of ether-wave vibration conditions the consciousness of color-quality, and the amplitude of the wave the consciousness of color-intensity.
Contrasted vidth the ever-present, relatively self-sufficient sensational elements, correlated as they are with definite physical and peripheral physiological phenomena, are two classes of elements of consciousness, the attributive and the relational. Within the former group this book includes attention, the affective consciousness of pleasantness and unpleasantness, and the consciousness of realness. Among simple relational experiences it has named the consciousness of ' one ' of ' many ' of ' like ' of ' different ' of 'more' of 'less' and the like. The following statements may be made about elements of both these classes, (i) It is at least probable that there are experiences which contain neither attrib* Cf. for consideration of a different view, p. 364, below.
Certainly we may have inattentive, indifferent consciousness untinged with the feeling of reality; and it is likely that the very primitive or very sleepy consciousness contains no consciousness of unification, of distinction, or of connection. (2) There are ol)\-iously no definite physical modes of stimulation and thus no end-organs of the attributive and the relational consciousness. (3) From the first of these characters it follows that an attributive or relational element is reflectively known as, so to speak, belonging to, attached to, another element or constituent of the complex experience of the given moment. And the relational is distinguished from the attributive element as belonging to at least two such other elements or factors. Thus. I am always conscious of a pleasant something — taste or familiarity; I attend to a color, I hold a sound as real. In other words, the attributive experiences are somehow 'attached to' sensational consciousness. Similarly, we are conscious of the likeness or unlikencss of one color or i)leasure or relation to another — that is, the relational consciousness is, as it were, subordinated to two other elemental experiences. These criteria of the elements of consciousness are, one and all, reflectively observed characters, facts later 'known aljout' the elements of consciousness. This statement is of importance as guafding against the charge of treating the characters of independence, attachedness, and the like, as if they were constituents of the elements of consciousness.
C. The Psychophysical Law
§ 35. The psychophysical law formulates a well-known relation between physical stimulation and sensational consciousness: the more intense a stimulus to sensation the more it must be altered in order that the accompanying consciousness may vary. If, for example, I am carrying a quarter pound of tea I sliall feci the weight of an added ounce, whereas the same ounce, if it were added to a pound or two-pound package, would be followed by no consciousness of additional weight. Similarly, in a quiet room I hear a fly's buzzing which I should not hear in a whirring factory. Psychological experimenting, especially in the early days, was largely concerned with the verification and llie application of this law. The general outcome of it is the following: to obtain a series of sensational intensities, just perceptibly different from each other, the series of physical stimuli must differ, one from the other, by a certain definite ])rop()rtion. The proportion varies with the form of stimulus: the degree of sound stimulus must increase by one-third, of gaseous olfactory stimulus by about one-fourth, of mechanical surface stimulus by onetwentieth, of mechanical j)ull by one-fortieth, and of light stimulus by one one-hundredth. For example, if one can just tell the difference between weights of one hundred and one hundred and five grams applied to the ends of the fingers, one will not be able to distinguish weights of two hundred and two hundred and five grams, but will barely discriminate weiglUs of two hundred and two hundred and ten.
SECTION IV
§ I. On the negative character of fusion, cf. C. S. Myers, op. cit., pp. 6-7. On the difficulty of analysis in fusion, cf. Titchener, " Experimental Psychology, Qualitative, Instructor's Manual," § 45; Kulpe, op. cit., § 42 ff.
§ 2. The teaching of this book, that there is an elemental consciousness of extensity, accords with the prevailing doctrine of contemporary psychology. It has been disputed, none the less, by acute psychologists who urge that the consciousness of extensity is no distinctive and elemental experience but rather a fusion in which the consciousness of eye or hand movements predominates. This account (the empiricist theory, as it is called) of the extensity consciousness is based mainly on two facts, abundantly proved: (i) that the newly born and those recently recovered from congenital blindness are unable rightly to estimate distances and to compare shapes; and (2) that our consciousness of form and of position includes the consciousness of eye and of hand movements. But these admitted facts do not disprove the occurrence of an elementary extensity consciousness. They prove that the space consciousness is a complex, including consciousness of movement; and that the capacity to measure and to compare forms and distances grows with experience. In other words, the empiricists prove that the consciousness of space is more than an elemental extensity experience, not that the consciousness of space is devoid of an elemental extensity consciousness.
The truth is that the empiricist theory is intended to oppose the so-called nativistic doctrine — the assertion that we are born with a ready-made consciousness of space. Against such a view
the argunu'Uts of the t'in[)iriiists d,) hold. But it is not iiropi-r to fonfound the ' nativistic ' tearhln<; al)out the time of the earliest space eonseiousness with the 'sensationalist' doctrine of an cxtensity element. For bibliography, cf. M. W. Calkins, "An Introduction to Psychology," ])p. 495, 496; and add on the sensationalist side, Kbbinghaus, Grundziigc, pp. 422 lY.; Titchener, "Text-book," I., 1909, § 12; S. Witasek, " Grundlinien der Psychologie, " 1908, p. 187.
§ 3. On the consciousness of apartness, cf. especially, Ebbing haus, op. cit., 436-437, and Lipps, cited by Ebbinghaus, p. 431. The doctrine of Chapter IV. differs from that of Lipps and Ebbinghaus in regarding the consciousness of apartness not as elemental but as fusion of the sensational consciousness of extension with tlie relational experience of plurality (" more^han-one-ness'). Ebl)inghaus tends to confuse this el(>mental I)ut relational consciousness with the more complex and jiartly sensational experience of apartness.
Von Erey has shown by experiment that successive e.xcitation of end-organs of pressure lying .side by side, however close to each other, gives rise to distinguishable pressure .sensations; but that the ])ressures thus distinguished are not always localized, eitlier correctly or incorrectly. Thus, a subject niay recognize two stimuli on his wrist, but may be unable to tell whether one is above or beside the other. Von Erey inclines to the belief that the ba.sis of distinction between these sensations must be a difference in l)ressure quality (ein qualitatives MerkzcicJien) ; but it is not improbable that the two sensations dilTcr in intensity or in extensity, rather than in quality.*
stimulus applied to the skin. If 1 sit blindfolded and some one touch me with i^encil point on forehead, hand, or chest, and if I am then ref|uired myself to touch the point of stimulation, I shall succeed api)roximately, although not without errors. And I shall be able to describe in words the place of contact. Evidently, this consciousness of the point of contact presupposes the consciousness of the body as a whole. The problem is to explain why the stimulation of a single point of the skin should excite the far more complex consciousness of the body as a whole, or that of a region of the body. Since the time of Lotze, that character or accompaniment of a tactual sensation through which it is referred to one part or another of the body has been called the tactual local sign. Similarly, the character of a visual sensation through which it is 'referred' to ofie part or another of the field of vision is called the visual local sign.
There are two theories of the local sign, (i) According to the first, or kinaesthetic, theory, suggested by Lotze, the local sign of either a visual or a pressure sensation is the consciousness (perception or imagination) of an habitual reflex movement of eye or of hand. (Such consciousness of movement may be supplemented by a concrete visual image of the part of the body stimulated, or by a verbal image, as of the word 'forehead,' 'arm.') The local sign of a visual sensation is the eye movement necessary to secure excitation of the fovea by the stimulating object. The local sign of a pressure sensation differs with the portion of the body excited — it may be, for example, the imagination of the movement by which a pencil, touching the wrist, slides toward the fingers.
According to (2) the other view, which may be called the element-theory, there is in every sensation an immediately realized, unspatial character due to the specific position of the bodily structures which are excited — due, for example, to the excitation of more or less closely crowded skin end-organs or retinal structures. This unnamed character* is to be confused neither with the consciousness of color or of pressure, nor with the experience of visual
The two accounts of tlie local sign differ therefore in the following way. The kina;sthelic theory conceives the local sign as associated jjerce])lion or imagination of movement ; the ' nativistic ' or elemental theory conceives it as an indescribable element of the sensation. But both agree in the important negative teaching that the local sign, because it is the character of a single sensation, is not itself a consciousness of place. For the consciousness of place, or position, is a consciousness of apartness — that is, of more-thanone-ness. It cannot then be a constituent either of the consciousness of stimulation of one skin-jjoint, or of the consciousness of any one point in the field of vision. In the words of James: "although a feeling of . . . l)igness may, a feeling of j)lace cannot possibly, form an immanent element in any single sensation." f
illusions of size, best illustrated by the Mliller-Lyer figure in which the line ab, though objectively equal to eh, appears longer; and (2) illusions of direction. To the latter class belong (a) the tw-odimensional illusions illustrated by the Zollner figure, in which the lines ab and cd, though parallel each with cf, yet seem to diverge from it in opposite directions, J and by the Poggendorf illusion,
* Cf. E. Hcring, and C. S. Myers, op. cit., 238 fT., with bibliography, p. 242. In favor of this view are urged (i) the alleged testimony of introspection; (2) the fact that localization occurs so soon after congenital blindness that there has been no time for setting up hat)itual eye movements.
in wliich the short line a/, though really a continuation of a/>, seems {iis])laced downward; and {li) the three-dimensional illusions of perspective, of which the example best known is Schroder's figure. This seems N to represent, especially if c be fixated, the upper side of a staircase, at other times — more readily if h be fixated — the under side of the same stairs.
The types of explanation most frequently applied to these illusions are either in terms of perception or in terms of attention. To the first group belong the following theo
Illusion.
(i) The figures are explained as illusions of reversible perspective. It is pointed out that the Schroder illusion changes according
*For summary of facts, and brief discussion of theories: Sanford, op. cit., 1898, Chapter VII., pp. 212 ff.; Titchener, Experimental Psychology, Qualitative, Teachers' Manual, 1901, pp. 303 ff. (Cf. especially bibliography, pp. 305 ff.) Cf. also Ebbinghaus, Grundziidge, 2ter Band, ite Lieferung, 1908, pp. 51 ff.
(2) The second ])ercei)lual ihrory <>f these ilkisions offers different accounts of differcnl illusions, but these all a<^ree in explainin_i,' the illusi(.)ns not through eye movements hut through certain innate retinal factors. f
(3) The third theory explains the illusions as due to eye movements.! In its earlier form this theory supposed that corresponding, point by point, with the peripheral changes due to (jur
eye movements perceptions of these movements occur, and that accordingly these spatial illusions are the consciousness of actual movements: that the line cb, for example, in Figure 24, seems shorter than ah because the eye actually executes a shorter movement. In this extreme form the eye-movement theor}^ is, however,
also Myers, op. cil., pp. 304, 298, 296.
X The enumeration of these three types of explanation leaves out of account not only many detail-e.xplanations and all forms of the explanation of the illusions as mainly phenomena of attention, but the systematic doctrine of Lipps (" Raumaesthetik u. geometrisch. optische Tiiuschungen," iSg"), based on the view that we regard every figure as a sort of personil'ied combination of opposing mechanical forces.
experimentally disproved l^y the experiments of Stratton,* Dodge,t J udd, X 3,nd others. These experimenters have photographed the actual eye movements made during observation of different forms, and have shown that we do not have an exact consciousness of the movements actually performed by our eyes. For, in the first place, as any ordinary obsen^ation of a moving eye confirms, the eye invariably makes a jerky movement in passing slowly over the field of vision, and yet we are totally unconscious of these pauses in the apparently continuous movements of the eye. And, in particular, the movements of our eyes in regarding such figures as that of Miiller-Lyer are not of the sort which, on this theory, are demanded. It simply is not true that, in looking at Figure 24, I am conscious of my eyes as following the outward sweep of the lines ad, ae, bf, hg, and that thus I overestimate ab, whereas I underestimate cb because my eye movements are arrested by the inward turn of ch, ci, bf, and bg. For experiments have shown cases of the Miiller-Lyer illusion in which there were no 'frequent «r marked modifications of the eye movements' in overestimating ab, and in which a short movement in looking at cb was supplemented by 'a secondary movement which . . . carries the eye to the true extremity of the underestimated figure. '§ Experiments on the ZoUner illusion show that for three out of four subjects the eyes were dellected in a direction opposite to that of the illusion.! I
Evidently the theory that the eye movements vary precisely with the illusion and that the illusion is itself a consciousness of definite eye movements must be abandoned. Yet, none the less, the Yale experiments show a parallelism, though irregular and
incomplete, of eye movements and illusion.* Tlic writer of this book accordingly holds it probable that (1) some more or less vague consciousness of eye movements is a constituent not only of our ordinary space consciousness but of this consciousness of illusions; that (2) it is impossible that specitic illusions can be explained by precisely corresponding eye movements; that (3) we must therefore suppose a characteristic, but so far undescribed, cortical change produced by the eye movements and in part, at least, conditioning the illusion. f It must, however, be admitted that so general a conclusion leaves almost unanswered the special problems raised by these geometrical i!lusit)ns. And it well may be that the illusions are explicable rather in terms of attending and of relating than in terms of sensation, whether retinal or motor. J
c. I . The Nature of the Consciousness of Depth
§ 6. Hering, James, and Stumpf are the main upholders of the doctrine that we are immediately and elementally conscious of depth as distinguished from surface. Cf. Hering, Beitrdge zur Physiologie, V., and Hermann's Handbuch d. Physiol., III., pp. 572 fif. ; Stumpf, "Die Ursprung der Raumvorstellung," 1873, Chapter H.; James, op. cit., II., pp. 212 ff. Most contemporary psychologists, however, though they admit an elemental factor in
* Yale Psychological Studies, 1905, N.S., I., pp. 81-, in-, 135.' t Professor Judd's conclusion is stated in these words: "Whatever sensory impulses can be brought into coordination and equilibrium by a single act will be grouped together. Whatever sensory impulses must be responded to by a succession of acts will be grouped apart." (Yale Psychol. Studies op. cit., p. 225-.)
X For explanation in terms of attention, cf. R. Schumann, Beitrdge, Zcitschr. fur Psychol., Bd. 23, i ff., Bd. 24, i ff., Bd. 30, 241 ff., 321 ff., and Ebbinghaus, cited on p. 338, pp. 69, 79, 83, et al. For explanation in terms of 'analytic' and 'synthetic' apprehension, cf. Benussi, " Zur Psychologic des Gestalterfassens," in Mcinong's " Untersuchungen zur Gegenstandstheorie," 1904, pp. 303 ff. For summary of these theories and for a somewhat similar explanation of the tactual illusions of filled and unfilled space, cf. Helen Dodd Cook, "Die taklile Schiitzung von ausgefulllcn und leeren Strecken," .irchiv/Ur die gesamtc Psychol., 1910, XVI., csp. pp. 539 ff.
all s])ace consciousness, yet teach in agreement with the doctrine of this book that the consciousness of distance, or depth, is complex, including, along with the elemental consciousness of mere bigness or extensity, other elements and, in particular, either a consciousness of movements or, at any rate, a consciousness due to movements. Cf. Ebbinghaus, op. eit., § 38, pp. 423 ff., and Lipps there cited.
§ 7. It is certain that the occurrence of disparate retinal images — that is, of right and left eye images which differ slightly — is an occasion of our consciousness of depth; for otherwise the stereoscopic illusion could not exist. Hering holds, indeed, that the occurrence of these disparate images is the sole and sufficient explanation of the visual depth consciousness. An apparently decisive objection to this view is the fact that depth is perceived in monocular vision when the occurrence of more than one retinal image is entirely excluded.*
§ 8. The monocular visual perception of depth is probably conditioned by accommodation, since it occurs when one eye is closed so that only a single retinal image can be formed. Yet (i) as Baird has shown, some individuals seem to lack, or nearly to lack, the monocular consciousness of depth. f And (2) as Judd has proved, by photographing eye movements, parallel movements of the closed eye are present in monocular vision: in other words, accommodation does not occur alone, but is ac-
t For the statement and criticism of a theory, that of F. Hiilebrand, which denies the influence on the depth consciousness of sensations due to accommodation, cf. J. W. Baird, "The Influence of Accommodation and Convergence upon the Perception of Depth." Ainer. Jour. 0/ Psychol., 1903, XIV., pp. 150-200, csp., pp. 163, 165, 192, 200. k
companicd hy hiiTnular eye movements/'-' I'inally (3) all exj)crimenters agree that, in monocular vision, the distance of far objects is less accurately measured than that of near objects or, in technical terms, that " the limens of approach are uniformly less tlian those of recession." Baird explains this phenomenon by the sup|)()sition that the relaxation of the ciliary muscle, when one regards far objects, occasions fainter tactual-motor sensations than the tension oi the muscle when one accommodates for near objects. t
^^ 9. Changes in the convergence of the eyeballs, like disjiarate images, are invariable correlates of the binocular consciousness of depth an(i distance. There is, however, a marked difference in the two situations. In perceiving depth one obviously cannot at the same lime i)erceive the retinal images, whereas one always perceives, however inattentively, the changes in convergence of the eyes. If I hold my two forefingers Ijefore my eyes, approximately in the line of clearest vision, the one about a foot and the other about two feet away from me, and if then I look from one to the other I am distinctly conscious of the movements which are made as the eyeballs converge less or diverge more. Not merely, then, are convergence and divergence conditions of depth perception, but the consciousness of the greater or less convergence is a constituent of tlie deptli or distance consciousness.
§ 10. A discussion of auditory localization must take account of its physical and physiological conditions and of its psychic nature. Such a discussion may profitably be based on an enumeration of the more important facts of auditory localization, as established by experiment. These are the following: —
3. (a) Sounds given in the median plane, that is, from front to back, are constantly confused. All investigators agree on this point. Yet median plane localization is capable of great improvement.f {b) Many other pairs of 'confusion points' occur, symmetrically situated with reference to the point at which the monaural stimulus is most intense. J
4. Discrimination of the direction of two sounds is keener when the sounds are given near the front and near the back (not, however, in the exact front or back) than when given at the sides. §
5. Equidistant sounds seem to vary both in intensity and in distance with different positions. In particular, a sound at the side (near the 'aural axis') seems louder and nearer than a sound in another position. ||
6. {a) Sounds seem to vary in timbre and even in pitch with different positions, {b) Complex tones — the tones of the voice, for example — are better localized than simple tones, such as those of a tuning-fork, ^f
On these results of experimentation a consideration of the physical conditions of localization has now to be based. Several inferences from the facts may be made with some assurance. First, binaural localization depends either [a) on the intensity, or (b) on the pitch and timbre, of sound stimuli, (a) A sound stimulus affects the right and left ear differently according as it is situated more to the right or more to the left. Localization is due in large part to this 'binaural ratio of intensities.' This is argued from the facts (i and 4, in the enumeration just given) that binaural localiza-
tion is superior to monaural; ami that sounds at the front or baek are better discriminated than sounds at the side. F(jr a sound near the front or the back affects the two ears with nearly e(|ual intensities, and consequently a change in the ratio of these intensities is readily noticed. The occurrence of confusion points is another argument to this conclusion, for the binaural ratio of sounds at confusion points is the same. Yet (b) variations in timbre and in ])itch, as well as variations in intensity, are conditions of l)inaural localization. This is argued from the introspection of observers, (cf. 6 above), and from the improvement, through practice, in median plane localization when sound intensities are equal for the two ears. (Cf. 3 (a).)
Second, monaural localization, also, is due both lo variations in tlie intensity and to variations in the pitch and the timbre of sound stimuli, (i) The dependence of monaural localization on the intensity of sound is shown by the relatively accurate and mainly monaural localization of sounds given in the aural axis. (Cf. 5, on p. 344). (2) The significance of pitch and timbre is shown by the cases of monaural localization (inaccurate, to be sure) of sounds which are not near the aural axis.
The physiological conditions of auditory localization are ne.xt to be discussed. They are not so readily assigned, and four different theories have, in fact, been held. Auditory localization has been attributed : 7?r5/, to the excitation of specific organs in the semi-circular canals;* and second, to the cutaneous e.xcitation of the shell and drum of the ear.f With greater probability, auditory localization is explained as due, third, to specific brain processes, in particular, to processes corresponding respectively with the consciousness of right and of left.t Fourth and finally, as the preachers used to say, auditory localization has been attributed to the occurrence of reflex movements, especially of head movements. §
Of these four physiological theories, the first has been decisively disproved * and for the second there is no im[)ortant evidence.f In default of any further explanation one has, thus, to choose between the last two ; and such a choice at once involves the problem : What is the nature of the consciousness of the position of sounds? Two types of description are in the field — the nativistic and the empiricist. The first or nativistic theory, corresponding with the theory of specific brain processes, either holds, with Stumpf, that special sensations of right and left occur or, with Pierce, it asserts simply that "auditory impressions originally possess positional characters." The second, or empiricist, account of auditory locaHzation teaches that the primary constituents of the distance consciousness are certain movements or tendencies to movement excited by the varying intensities and qualities of sounds.
The writer of this book inclines to adopt the 'motor' theory just stated. According to this view, auditory as well as visual localization is primarily describable in terms of perception or imagination of bodily motion supplemented, for all seeing people, by visual imagination of the body and its environment. The movements, perceived or imagined, which condition this consciousness may be movements of the body as a whole, or even eye movements, toward the source of sound. The physical conditions of these movements are the varying intensities and qualities of sound stimuli.
Two amplifications of this statement are necessary. It must be noticed, in the first place, that such a motor theory need not imply that every consciousness of position is conditioned by a definite reaction, reflexly excited, and that it consists in the consciousness of this precise reflex movement. The notorious errors
* Cf. Breuer, Bloch, p. 18; Pierce, 139 ff., esp. p. 142'. The point of Bloch's criticism is that all sound waves must affect the semicircular canals alike, since all reach it through the external meatus.
t Cf. Angell and Fite, pp. 236, 246. It should be stated that this criticism does not deny the fact that the pinna, or shell of the ear, may dellect the direction of sound-waves and thus, indirectly, affect localization. Cf. Bloch, pp. 36', 48^; Starch, 1905, p. 24.
of localization, aiul the failures of attempts to demonstrate an cxat t parallel between bodily movements and accurate localizations, make this view untenable.* It will be observed, in the second place, that a motor theory is entirely compatible with an admission of the significance of visual imagination (either the imagination of feet, face, or hair, or the imagination of certain j)arts of the ordinary environment) in the consciousness of 'up' and 'down,' 'front' and 'back.' It is even possible that, in the developed localizing consciousness of some subjects, these visual images may have crowded out the motor consciousness. Originally, however, and probably in most adult e.xperiences, these visual images are supplementary to the percejjts or images of instinctive motor reactions to the source of sound.
It is at once evident that this theory is readily harmonized with the facts established by obsen^ation. In particular, it accounts for the lack of confusion between right and left. And it explains the errors in localizing sounds in the median [)lane, for such sounds are equidistant from right and left ears, and there is consequently no tendency to move rather in the one direction than in the other. It has furthermore a decisive advantage over every visual theory in that it offers an e.xplanation of the consciousness of right and of left. For how conceivably can right be distinguished from left in purely visual terms? Right and left, as Kant long ago pointed out, are perfectly symmetrical, and accordingly there .seems to be nothing by which to distinguish either the visual (or the merely tactual) consciousness of the right of my body from that of the left. The psychologist has, therefore, to adopt either the motor theory, which conceives the right as 'that which is realized to be more mobile,' or he has to espouse the StumpfPreycr theory of .specific right and left sensations. This Stumpf theor}', it will be admitted, is readily harmonized with many facts of localization, yet it is open to important objections: (i) The
* Thi.s admission, rouplod with t!ic rccogniu'on of hixiy and cvi- movrmcnls, as well as head movements, as conditions of localization, seems to meet the objections raised by liloch (p. 19) and by Pierce (pp. 150 fT.) to the Miinsterberg theory.
tht'Dry requires the hypothesis of j)recisely similar end-organs whose excitation results in different sensations merely because the organs are situated respectively to right and to left. This supposition clearly is contrary to physiological analogy. (2) Many children learn but slowly to distinguish right from left, and some i)eo[)le never learn to make the distinction save through artificial associations, that, for example, of the left with the ring finger. This would scarcely be possible if there were immediate and original sensations of right and of left. (3) Simultaneous sounds of the same quality, given one to the right ear and one to the left, fuse into one sound attributed to an intermediate position. This fact is readily explicable by the supposition of a single movement as resultant of stimuli to two opposed movements, but is not easily harmonized with the hypothesis of distinct right and left sensations. For these reasons, the Stumpf theory can scarcely win assent, and Pierce's form of the nativistic theory is too indefinite to serve the purpose of a localization theory.*
The strongest objection to this modified form of the motor theory is based on the results of experiments showing that two sounds of different quality simultaneously given, one from the right and one from the left, are often simultaneously attributed to approximately their actual positions. Such localization seems to involve an opposition and consequent cancelling of rightward by leftward movement. f The objection, however, loses most of its force when it is remembered first that the memory of movements
* Pierce seems virtually to admit that undifferentiated 'positional characters ' play no part in localization, for he says (p. 193-) "When I say that a sound is 'here' or 'there' ... I mean . . . the sort of reaction that must be made in order that the sounding body may be seen or touched or brought to the position of most distinct hearing." His main argument for positional characters is based on the fact that, under experimental conditions, a sound may be localized in the head, and on the conclusion that such localization must be elemental because (p. 181) "neither vision nor touch has any actual experience with the endocephalic masses." This observation, however, directly contradicts that of the writer and of others, who certainly sometimes have a visual image, very schematic, of the interior of the skull.
may perhaps persist when actual inoveinent is clicckccl, and second, that so-called simultaneous localization may well consist in a consciousness of rightward swiftly succeeded by that of leftward movement.
Bibliography. — J. R. Angell, A rreliminary Study of the Significance of Partial Tones in the Localization of Sound, Psychol. Rev., 1903, X., I IT. ; Angkll and Fitk, The Monaural Localizalion of Sound, Psychol. Rev., 1901, VIII., 225 ff. and 449 IT.; K. Bloch, Das binauralc Iloren, pp. 61. \\'iesbaden, 1893 (of. A. Gambli:, The Perception of Sound Direction as a Conscious Process, Psychol. Rev., 1902, IX., pp. 357 ff. ; Gamble and Starch, W'eiicsiey College Studies, Psychol. Rev., 1909, XVI., pp. 416 ff. ; J. vox Kkies, Uber das Erkennen der Schallrichtung, Zeitschr. fur Psychol., 1890, I., 236 ff. ; M. Matsumoto, Researches on Acoustic Space, Yale Studies in Psychology, V., 1897; II. MiJNSTERBERG, Raumsinn desOhres, m Bcitrdg zur experimcntallcn Psychologic, II., 1889; Miixstkrberg and Pierce, The Localization of Sound, Psych. Rev., 1894, I., 461 ff. ; W. Preyer, Die Wahrnehmung der Schallrichtung mittiest der Bog ngange, Pfliiger's Archiv, 1887, XL., 586 ff. ; D. Starch, Perimetry of the Localization of Sound, Part I., University of Iowa Studies in Psychology, 1905; Part II., ibid., 1908; K. Stumpf, Uber den psychologischen Ursprung der Raumvorstellung, 1873; Ton psychologic, I. (1883), esp. pp. 207-210; II. (1890), pp. 50 ff. ; V. Urbantschitsch, Zur Lehre von der Schallrichtung, Pfluger's Archiv, 1881, XXIV., 579 ff. ; W. Wundt, Grundzuge der physiologischen Psychologic, II.^ 1902, 486 tT. ; Wilson and Myers, British Journal of Psychology, 1908, II., 363 ff.
§ ir. Bibliogr.'\phy. — On the consciousness of Jiarmouy and of melody : cf. above, pp. 315 ff. on beats; al.so Ebbixghaus, Grundziigc, pp. 298; H. VON Helmholtz, Sensations of Tone, 1895, chapter XII. ; K. Stumpf, Tonpsychologie, II., esp. §§ 23-26, 28; and Diffcrenztone und Konsonanz, Zeitschr. fiir Psychol, 1905, XXXIX., 269 ff. ; R. Konig, Uber den Zusammenklang zwcicr Tone, Poggeiidorff'sAnnalen, CLVIL, p. 177, cited by El)binghaus, op. cil., pp. 305, 308; F. Kruger, Das Bewusstsein der Konsonanz, 1903; M. Meyer, Uber Kombinationslone u. s. w., Zeitschr. fur Psychol., 1896, XL, 177; F. Weinmann, Zur Struktur dcr Melodic, Zeitschr. fiir Psychol., 1904, XXXV'., 340 ff.
§12. Bibliography. — On the consciousness of rhythm: T. L. Bolton, Rhythm, American Journal of Psycliology, 1893, I., 14c; IT., 310 fT.; E. Meumann, Untersuchungen zur Psychologic und Aesthetik des Rhythmus, Philos. Studien, 1894, X., 249 tT., 393 fi". : M. K. Si\iiTH, ibid., 1900, 71 IT., 197 ff.
I. The Psychology of Instinct
§ I. The study of instinct is common ground to biologist and lo psychologist proper. From the Ijiological point of view the instinct is an unlearned, or innate, reaction of organism to environment, normally characteristic of a family or species, and j)resumably of use to the race and often, also, to the individual. (A distinction sometimes made between the instinctive as coordinated and complex reaction and the reflex as simple seems to the writer to add an unnecessary character. A baby's first vague movements, though uncoordinated, are properly called 'instinctive. ')
The psychologist is concerned both ^\^th the instinctive bodily reaction as sequent or accomjjaniment of the conscious relation of self to environment and with the instinctive consciousness — whether jjerceptual or emotional. (For modes of consciousness as well as movements may be distinguished as instinctive or acquired.) In both cases the fundamental distinction, never to be obscured, is between the unlearned and the acquired. In other words, a mode of consciousness or a reaction which has not been acquired is to be called instinctive, even if one cannot as yet prove it to be a race-activity, and even if one cannot prove it to be u.seful in the perpetuation or development nf the race. In truth, the utihty of an activity or experience is a trait too difficult of observation and demonstration to be named as primarj'' mark of instinct. Accordingly, the definition of 'instinctive action' as 'something purposive but involuntary'* subordinates the fundamental to the secondary character.
* Wundt, "Lectures on Human and .\nimal Psyrliology," XXN'II., § i, Kng. tr., p. 395. Cf. Schneider, "Der thierische Wille," p. Oi, and James, "Psychology, Hricfcr Course," p. 30T.
Yet, though the instinct he not defined as useful, it rcinains true that the constant result of biological study is to discover the usefulness of instinctive reactions. For the individual, indeed, an instinctive act may be useless or perilous — for example, the water hen flicks her tail before the undertail has grown white so as to serve as signal; and the insect dies in the act of laying her eggs; Ijut for the race the instinctive activity is reasonably inferred, if indeed it is not olxserved, to be of use. And llic utility of instinctive reactions is the presupposition of all theories a!)out their origin.
From three different points of view one may profitably classify instincts. There is first the contrast between habitual instincts, such as walking and swimming, and instinctive movements which are seldom, or even once, performed — the reaction, for example, of the yucca moth to the flower which, once only, it fertilizes with the pollen of another flower that opens on one night only. There are early instincts, such as pecking and sucking, and deferred instincts — walking, for example, and biting. Indeed, specific instincts, mental as well as bodily, mark off successive life stages from each other. There is an age when most children are instinctively social, followed — and perhaps preceded — by a period of instinctive shyness. There is an age when a boy is instinctively a hunter, or a collector of treasure. The wise teacher will eagerly foster and stimulate the transitory instincts which should issue in permanent habits, and will limit the outflow of the dangerous instincts. The child thus trained may form gracious habits of social intercourse which will tide him over the shallows of his shy age, and may outgrow his tormenting instinct without forming habits of cruelty.
This reference to the training of instinct suggests the third distinction, pedagogically most important of all, that between unmodified and modified instincts. The main difference, as James has pointed out, between animals and men is, from this standpoint, not as usually stated, that animals have many instincts and men only a few. On the contrary, the difference is simply this : that
anim;il instinrts arc largely unnKxlificd, whereas both the animal and the s|)C(iri( ally liunian instlni ts of men are modified, sometimes indeed completely checked (that is, 'inhibited'). The simplest way of modifying instinct is by controlling, limiting, and altering its objects. The boy's combative instinct may be directed toward weeds and woodpiles in place of smaller boys, his acquisitive instinct may be turned in the direction of postage stamps in place of posters. Again, an instinct may be modified by exciting another and an inhibiting instinct. To the little child, for instance, a strange object is naturally both interesting and terrifying; and it therefore rouses the opposite instincts of apjjroach and withdrawal. The child may slowly come close to the strange dog or to the new motor-car, or he may gradually shrink back, or tinally one instinct may balance another and he may hold his ground, neither advancing nor fleeing, but revealing by hesitating movement and changing expression the conllict of instincts. In quite parallel fashion the instinctive selfishness of the older child may struggle with his instinct of generosity. One may watch his vacillation between the instinctive movement to snatch from his playmate tile coveted marbles and the altruistic instinct to give up those which he has himself rightfully won.
The pedagogical ap})lIration is clear. Instincts should be controlled, not inhibited. The ideal of education is not an ascetic life of crushed instincts, but rather a life in which every instinct is brought into joyous captivity to right ends. Shyness and sociability, acquisition and combativeness, the instinctive desires for personal good and for the hapjiiness of other selves, the sjjccific desires for food and wealth and beauty, — all have a rightful place in life when coordinated with each other, directed to good objects, functioning at proper times, and subject, in the last resort, to the control of will.
the acquisition of new bodily dexterities or of novel experiences.* Normally, of course, the two forms are combined, and learning is psychophysical. The education of hand and muscle implies a corresponding training of reasoning and will; and the coordination of movements accompanies the coordination of thoughts. The acquisition of new bodily reactions is biologically important because the animal possessed only of fixed, inherited instincts is helpless in face of violent changes in his environment : the animal, for example, who devours every food succumbs to poisons or to fishhooks. On the psychic side, the inability to learn would imply the lack of creative imagination and of reasoning, — the two main forms of psychic learning. A creature which could learn nothing would simply retain its original stock of percepts, feelings, and reactions ; it would receive like impressions day after day, and would react on them in the old, inevitable ways. It would be unaffected and unmodified by its own experiences.
The main purpose of this section is to make the distinction, particularly as regards psychical reactions, between the indi\idual and the social form of learning. f A preliminary statement is important. All learning, whether physical or psychical, presupposes consciousness in the form of memory. For this reason, indeed, conservative biologists propose as test of consciousness the ability to modify instinctive reactions and to profit by accidental experience. Contemporary comparative psychology largely concerns itself with the experimental study of animal learning. The first result of these studies, constantly in progress, has been the positive proof that animals, low and high in the biological scale, learn by individual experience. Thus, Yerkes has shown by his experiments that turtles can learn new reactions : his turtles, while crawling to the base of an inclined plane for food, accidentally fell from its side, and learned to repeat this fortunate method of shortening the path to food.| Evidently this perpetuation of an accidental reaction indicates that the turtles remembered
the fall and its results. Similar experiments on birds, rodents, and the higher vertebrates, offer conclusive proof of an ability to learn new reactions. Certain e.xperiments of Professor Jennings seem ts) prove also that even some unicellular animals alter their reaction according as the stimulus is posterior or anterior.
All these are cases of purely individual learning. By social learning is meant learning by imitation; and it is still a moot question whether or not animals learn by imitation. It is nccessar>' to distinguish sharply between imitation and mere fortuitous and instinctive repetition — as when the roosters of a barnyard crow in swift succession, not imitatively, but because all react immediately to their environment. A second important distinction must be made between merely mechanical and reflective imitation. It is altogether likely that many animal reactions are " mechanical imitations, known as such by the observers, not by the performers, in which the action of one animal serves as the direct stimulus (of another animal's act)."* Reflective imitation, however, — imitation in the only strictly psychological sense, — involves one animal's consciousness that he is repeating the act of another. It is obviously difficult to prove experimentally that imitation in this sense occurs. Many experiments, notably those of Thorndike, have told against the probability of animal imitation. Dogs, cats, and monkeys have been shut up with other animals which have learned to perform certain simple movements, by which to release themselves from captivity or to obtain food, and yet the newcomers have failed to imitate the successful reactions of their companions. With still other animals, however, notably with anthropoid apes, experiments have indicated the presence of reflective imitation. The unsuccessful cases seem to be due to the difficulty of inducing animals to hx their attention on each other.
The contrast between the human and the animal consciousness is nowhere more striking. It has appeared already, in Chapter XV., that a vast number of normal human activities are imitations. And the phenomena of hypnotism are merely the abnormal manl-
festations of the instinct of imitation. Even more, perhaps, through imitation of his fellows than through profiting by individual experience, man struggles out of ignorance into his measure of wisdom.
On instinct: works cited, pp. 87, 351, and 376; H. R. Marshall, Instinct and Reason; K. Grogs, The Play of Man, The Play of Animals; G. Schneider, Der menschliche Wille.
On learning in animals: cf. M. W. Calkins, The Limits of Genetic and of Comparative Psychology, British Journal of Psychology, I., pp. 267 flf., and Allen, Bethe, Jennings, Loeb, Peckham, Small, Watson, and others, there cited; also R. M. Yerkes, Journal of Philosophy, 1905, II., 141.
On imitation in animals: cf. E. L. Thorndike, Animal Intelligence, Psychol. Review Monograph Supplement, No. 4, The Mental Life of the Monkeys, ibid.. No. 15, 1901 ; C. S. Berry, An Experimental Study of Imitation in Cats, Journal of Campar. Neurol, and Psychol., 1908, XVIII., pp. I ff. ; Haggarty, Imitation in Monkeys, ibid., 1909, XIX., pp. 337 flf; also BoHN, L. W. Cole, Kinnaman, Porter.
On habit, instinct, imitation, and learning in children: cf. the biographical studies of child psychology, by Preyer, Perez, Shinn, Moore, E. A. KiRKPATRiCK, Genetic Psychology, Chapters IV., V., X., with bibliograpliies; and the journals, in German and in English, devoted to child psychology.
§ I. For advocacy of the view that attention is elemental, the student is referred to Titchener, as cited l)elow. Attention, or 'clearness,' is, according to Titchener, 'an indc|jcndent attribute of sensation' — that is, attention is cocirdinate with sensational intensity and extensity, and thus (in the terminology not of Titchener, but of the writer) itself elemental.
§ 2. The main difference between the teaching of Titchener and that of this book has been indicated in tlie last sentence. Titchener holds that attention, 'sensible clearness,' as he calls it, is purely sensational, — in other words, that we can attend to 'sensible objects only,' to sights and sounds, never to our affective ex{)erience, our emotions.* The introspection of the writer does not confirm that of Titchener on this point. Unquestionably, prolonged attention to emotion as such, to one's happiness or unhappiness, diminishes, [)erhaps even destroys, the affective quality. In the words of Maeterlinck, "il n'y a aucun bonheur dans le bonheur lui meme tant (ju'il ne nous aide pas a songer a autre chose." But similarly, attention to [)erception — as distinguished from attention to the perceived — is likely to destroy perception as such, that is, to turn perceiving into thinking. The irutli is, that introspection is attention. f We must therefore be able, if only for a brief time, to attend to pleasantness and unpleasantness, else we should not introspective ly distinguish the affections from their sensational accompaniments. |
* The question whether we attend to relations does not, for Titchener, e.\ist, because he believes that the relational consciousness reduces to sensational elements. (Cf. p. 364.)
There is great vagueness and indecision in most discussions of attention. The reader is referred especially (i) to the discussions of Wundt, in the "Lectures on Human and Animal Psychology," XVII., the "Grundriss" (§ 15), and the "Grundziige der physiolog. Psychologie, " III.'', 1903, pp. 331 fif. ; (2) to C. Stumpf, " Tonpsychologie," I.,67ff. ; II., 276 ff.; (3) to E. B. Titchener, "The Psychology of Feeling and Attention," 1908 (with extensive bibliographies) .
The doctrine of Titchener has been briefly summarized. Wundt teaches the elemental character of attention,* or clearness, though not always from a purely structural standpoint. Stumpf's opinion is that " attention is identical with interest and interest is a feeling." Accordingly, he defines attention as " Lust am Bemerken selbst. "f He emphasizes the prolongation, through association, of the object of attention.
For discussion of the neural conditions of attention, cf. Titchener, op. cit., pp. 206 and 359 (Note 42); W. McDougall, Mind, 1903; M. Meyer, Psychol. Review, 1908, XV., pp. 358 £f. ; 1909, XVI., pp. 36 £f. ; and (for summary to date), A. J. Hamlin, Amer. Jour, of Psychol., 1896, VIIL, 3 fif.. Chapters I.-III.
Cf. also M. W. Calkins, " An Introduction to Psychology, " Appendix VII. (for brief classification of types of attention doctrine), and W. B. Pillsbury, " L' Attention, " 1906, and "Attention," 1908.
Association and Memory
§ I. The following table states the relations between fusion and association on the one hand, successive and simultaneous association on the other. The term 'assimilation' may, however, be used, as on page 65 of this book, to cover both the elemental and the complex form of simultaneous association. A simultaneous association consists essentially in the persistence of the first term of a successive association.
For sliglitly varying uses of these terms, and for further distinction between forms of fusion, cf. Klilpe, " Grundriss der Psychologie," §§ 42 ff.; and Wundt, "Grundziige," 11.^, pp. 526 ff.
§ 2. On the classification of association as total or partial, cf. James, "The Principles of Psychology," Vol. I., pp. 569 IT., 578 fif., and " Psychology, Briefer Course," pp. 259 fiF. For criticism of the older division between ' association by contiguity ' and 'association by similarity,' cf. F. H. Bradley, "The Principles of Logic," p. 294 ; James, " Principles," I., pp. 590 fif. ; M. W. Calkins, "Association," pp. 12 ff. For examples of association suitable for analysis, cf. this Appendix, Section XVII., pp. 403-404.
§ 3. The study of the nature of associations, as the.se vary from time to time, and from individual to individual, has been carried on by experiments of two main types, 'spontaneous' and 'con-
trolled.' Spontaneous associations arc very readily studied through a simple experiment (which may indeed be performed with a whole class of students as subjects). The instructor pronounces a word, directing the students to write, as (|uickly as possible, a word or phrase descriptive of the lirst suggested image ; next, to write a word (or phrase) descriptive of the second image suggested ; and so on, for a given period — one minute, for example. The resulting scries of associations is v;orked over by each writer, in order to discover the type of connection. Thus, the association of 'swallow' with 'nest' may be due to the writer's interest in birds, the association of ' nest' with ' boy' may be due to his recent reading of a story of robbing nests ; the association of ' boy ' with 'blue' may be due to the frequency of liis repetition of "Little Boy Blue." Experiments of this sort are well suited for comparing the associations and imagery of different individuals and groups. A child's list of associations differs materially from an adult's, a farmer's from a sailor's. Such a comparison is facilitated if the suggestive word is ambiguous — some such word, for example, as ' swallow' or ' ball ' ; for the first word on a given list is likely to indicate an interest or occupation of the writer: Thus, a boy might write 'nest' after 'swallow,' while a physician would write 'throat.'
In experiments of the 'controlled' variety, the subject is not left free to imagine what he will, once he has been started. Rather, a list of words is read him and he records his first association to each. The list is carefully selected, usually with a view to furthering one sort of associations rather than another. The more serious experiments are carried on with one suljjcct only, and the time of the association-reaction is measured, that is to say, the time which intervenes between the moment when the subject hears a word and the moment when he responds with the word thus suggested to him. Controlled association experiments of this type are nowadays used as a method of mental diagnosis. It is found that the association-reaction is lengthened, even against the will of the subject, when the suggesting word has to do with an emotionally interesting experience.
Professor Miinstcrherg lias i^roposcd to test the connection of suspected persons with a given crime, by requiring them to indicate the 'idea associated' by each one of a list of words, and by including in the list words suggestive <jf the crime or its surroundings. Similar experiments have been used in the effort to discover both from the nature and from the time of the associations the source and objects of the mental disturbance of the cerebrally diseased.
Bibliography. — On this form of mental diagnosis: C. G. JuxG, Dlagnostische Associationsstudicn, Bcitrdgc ziir cxp. Psychopalliologic, I., 1906, and Zur Tatbestandsdiagnostik, Zcilsclir. fiir angewandte Psychologic, 1908, Bd. I., 163 ff. ; F. Kramer and W. Stkrn', Scll)slverrat durch .'\ssocialion, Beitrdge zur Psychol, dcr Aussage, 1906, IV.; H. MuNSTERBicRG, On thc Witness-stand, 1908, csp. pp. 73 ff. ; M. WkrtHJiiMER, E.\ peri men to lie Untersuchungen zur Tatbestandsdiagnostik, Archiv filr die ges. Psychol., 1905, VI., 59 fF. ; R. M. Yerkes and C. S. Berry, The Association Reaction Method of Mental Diagnosis, American Journal of Psychology, 1909, XX., 22-37 (with bibliography)
On 'psychoanalysis' (the form of mental 'diagnostic' in which the experimenter is in complete ignorance of his subject's mental history) : Breuer u. Freud, Uber den psychischen Mechanismus hysterischer Phanomcnc, Neurolog. Zentralblatt, 1*893; Freud, Zur Psychopathologic des Alltagslebcns, 1904; J. II. Schui.tz, Psychoanalyse, Zcilschr. fiir angewandte Psychol., 1909, II., 440 tT. (with l)ibliography).
§ 4. On memorizing, cf. E. A. Gamble, The Reconstruction Method in Memorizing, Chapter III.; Mbbinghaus, Orundziige, §61; H. J. Watt, The Economy and Training of Memory, 1909; St. Augustine, Confessions, Book X., Chapter 8 ll.
I. Experimental Study of Recognition
§ I. Experiments on the nature of the familiarity consciousness were planned and carried through by A. Lehmann (Wundt's Philosop/iistiic Sdtdien, Bd. VIL, pp. 169 ff.). He tested several observ'ers with a series of 66 odors, and found (in opposition to his own prepossession) that in 7 per cent of the cases the subjects recognized the odors without being able to name them or to connect them with other experiences. Similar experiments were carried out, in the Wellesley College laboratory in greater number and under stricter conditions, with the results summarized above (p. 126). Cf. Gamble and Calkins, Zcitschrift fur Psychol, und Physiol, der Sinnesorgane, 1903, Bd. 32, pp. 177 £f.
§ 2. The doctrine of elements of consciousness which are neither sensational nor in any sense coordinate with the affections or feelings is upheld by psychologists of the most diverse schools. Herbert Spencer was the first to name and to discuss them,^* but his teaching attracted little notice, and thirty years passed before Ehrenfels rediscovered the Gestaltqualitdten,^ and James wrote of the 'transitive feehngs' of 'and,' 'but,' and 'if.'^ To-day two groups, or schools, and several individuals among Continental psychologists and a considerable number of English-speaking psychologists more or less unequivocally teach the occurrence of elements of consciousness neither sensational nor affective. There is, first, the school of Meinong,^ Hofler,^ and Witasek,"
* The Arabic numerals of this section (Appendix VHI.,§ 2) refer to the numerals of the Bibliography which follows (p. 365). The section is condensed and revised from a paper in The A:ncrican Journal of Psychology, iQog, XX., pp. 269 ff.
which discusses relational elements under the names 'fundirle Inhalte'' and ' Gegensldndc hoherer Ordnung.^ The second of the Continental schools is that of Kiilpe and the students and workers in the Wiirzburg Institut, Watt/ Ach,** Messer," Biihler,'" and others. Individual upholders of the theory are Binet," Stumpf ^with his doctrine of Gebilde and Verhdltnissc, CorneHus/^ and, finally, in spite of great divergence in terminology, Ebbinghaus " and Miinsterbcrg.'''
Of writers in I*>nglish, Stout.""' R. S. Woodworth,^^ and the writer of tliis book,''* have most explicitly taught the occurrence of these elements of consciousness, neither sensational nor affective, which are especially characteristic of what is called thought. Judd, also, describes concept and judgment in terms of relation ; ^' and Angell, in spite of his denial of literally imageless thought, seems to indicate by his term 'meaning' a relational experience.-"
It thus appears that the introspection of a score of psychologists, of different periods, prepossessions, and training, speaks unequivocally in favor of the occurrence of elements neither sensational nor affective.
It must be added that this testimony has been fortified, in recent years, by the attempt to control introspection through experimental conditions. One of the latest of such investigations is made by Biihler, whose method — a modification of that of Marbe and Messer — is, in brief, the following : He puts to his subjects, trained introspecters, questions answerable by 'yes' or 'no,' which are intended to excite their thought. After a question has been answered, the subject at once analyzes the consciousness preceding and leading to his answer. The questions are suited to the interests of the subjects. Illustrations are: "Can you reach Berlin in seven hours?" "Does monism mean the annihilation of personality?" The results of the investigation have been (i) the assertion in most cases by the observers that they are distinctly conscious of unsensational and nonaffective e-xperiences; (2) the apparent occurrence of some cases where no image, verbal or concrete, can be detected; (3) the
confirmation of this inlrospection by the discovery that a sul)ject often remembers not the images, but only the relation — say, of likeness or of opposition — in an earlier experience. Wundt^^ has very sharply criticised the method of these experiments on the ground, mainly, that it involves disturbance of the subject, and that it does not admit of repetition and variation of the experience to be studied. In the opinion of the writer, Biihler successfully meets this attack, appealing to the records of his subjects for evidence of their being undisturbed; and holding that repetition and variation are, in fact, obtainable in the essential sense that questions of the same or of regularly varying types may be repeated.
Wood worth's method and results resemble those of the Wiirzburg school, except that he confines himself to the study of comparison (the discovery of equivalent relation), and that in one group of his experiments he offers concrete material — colors and forms — for comparison. Earlier experimenters have found traces of relational experiences in the course of investigations concerned primarily with association. The experiments, for example, by which Professor Gamble and the writer tested Lehmann's assertion that recognition consists in associated images, disclosed a large number of cases in which the consciousness of familiarity, occurring markedly earlier than any associated images, is, in the view of the writer, most readily described as relational experience.
The criticism of the relational-element doctrine has, however, achieved one important result : it has effectively challenged the assertion that imageless thought occurs. For it is always possible to question the completeness and the accuracy of the introspection on which this conclusion is based. And, as Professor Titchener^^ and others have shown, it is probable that introspecters have often overlooked the occurrence in thought, and in recognition, of characteristic kinsesthetic and organic sensational elements. But the admission that thought and recognition contain sensational factors does not disprove the result of such multiplied introspection : that along with imagery, and often
recognizes, are elements neither sensational nor affective.
Bibliography. - The founders of the doclrine: i. II. Spkmckr, TIic Principles of Psychology, first cflition (1855), §8r, p. 285. 2. Chr. Ehrenfels, Vurteljahrsehr. fiir tmssenscJuifllichc Philos., XIV., p. 24Q, 1890. 3. W. James, I'rinciplcs of Psychology, I., pp. 247 ff., with Note.
Writers of the Meinang School: 4. A. Meixong : Zeitschrift, II., p. 247, 1891 ; and XXI., pp. 182 fF. ; and Ueber Annahmen, 1902. 5. :\. Hofler (Psychologic), and 6. S. Witasek (Grundlinicn der Psychologic, 1908), have incorporated Meinong's doctrine in systematic treatises.
Writers of the Wiirzburg School: 7. H. 8. N. AcH, Ueber die Willenstatigkeit und das Denken (based on experiments carried on in Wurzburg and in Gottingen), Gottingen, 1905. 9. Messer, Archiv, VIII., i ff., 1906. 10. K. BUHLER, Archiv, IX., 297 ff., 1907; XII., 9ff., 1908. (.\ccount and defence of experimental investigation. For account of experiments by similar method, cf. K. Marbe, Experimentell-Psychologische Untersuchungcn Uber das Urteil, Leipzig, 1901.)
Other continental psychologists: 11. A. Binet, L'dtude experimentelle de rinlcliigcnce, Paris, 1903. 12. C. Stumpf, Erscheinungen und Psychische Funktionen, Konigl. Akad. d. Wissensclmfien, Berlin, 1907, pp. 7 ff., 29 ff. 13. H. Cornelius, Psychologic als Erfahrungswissenschaft, pp. 70, 164 et al; cf. also Zeitschrift, XXII., pp. loi ff. (1899), where Cornelius develops a teaching of G. E. Muller. 14. Ebbinghaus recognizes as elements only sensations and affections, while 15. Mi'N'Sterberg admits sensations only. Yet the first includes under the head of 'general attributes of sensation' (Grundziige, I., pp. 410 ff.) anrl the second grouj^ in the class of value-qualities (Grundziige, I., pp. 290 ff.) what are here considered as relational elements.
Contemporary English-speaking psychologists: 16. G. Stout, Analytic Psychology, I., pp. 66, 78-96; II., p. 42. 17. R. S. Wooihvorth, Imageless Thought, Journal of Philosophy, Psychology, and Scientific }fethod, III., pp. 701 ff., 1906; The Cau.se of a Voluntary Movement in Studies in Philosophy and Psychology by Students of C. E. Carman, pp. 351 ff. ; Non-Sensorial Components of Sense-Perception, Journal of Philosophy, etc., IV., pp. 164 ff., 1907. 18. M. W. Calkixs, An Introduction to Psychology, 1901, Chapter X. (especially in the second edition, 190O; Der doppelte Standpunkt in der Psychologie, 1(705, PP- 25 ff.
this view.
Critics: 21. I. M. Bentley, American Journal of Psychology, 1902, pp. 26911. 22. R. SciiiTM.WN, Zeilsclir. 1898, XVII., pj). 128 ff. 23. E. B. TiTCHENER, E.xperimental Psychology of the Thought Processes, 1909. 24. W. WuxDT, Ueber Ausfragee.xperimente, Psychologische Sludien, 1907, III., pp. 300-360. (A criticism of Biihler. Cf. Biihler's reply, Archiv, XII., esp. pp. 94, 103, 107; and Wundt's rejoinder to the reply, ArcJiiv, 190S, XL); 25. Von Aster, Zeitschr. fiir Psychol., Bd. 49, 56 fif. ; 26 DiJRR, ihid., 313 ff. (Cf. Buhler's reply, ibid., Bd. 51, 108 ff.) 27. S. S. CoLViN, Psychol. Bulletin, VI., p. 236 and VII., p. 59.
Bull., VI., 369 ff.
On the consciousness of time: cf. Munsterberg, op. cit., pp. 244 ff.; Ebbixgh.\us, op. cit., 457 ff. (in which a doctrine of elemental time-consciousness is set forth); and B. Bourdon, La perception de temps, Revue Philosophique, 1907, LXIIL, pp. 449 ff.
§ 3. The term 'feeling' is nowadays usually employed to cover the consciousness of pleasantness and unpleasantness and any strictly coordinate elemental experiences. Both Spencer* and James, t on the other hand, and more recently W. Mitchell,| refer by the term to any experience whatever, elemental or complex. This usage seems to the writer of this book highly convenient, because there is no other single word which can well be put to this sendee, whereas ' feelings ' of pleasantness and unpleasantness may be termed 'affections' and grouped with any coordinate experiences under the term 'attributive elements.' This general application of the term 'feeling' has, however, met with little approval, and accordingly the word is seldom used in this book except in the narrower sense.
Notes on the Nature of Thought and Generalization
§ I. On thought as sharing or shareable consciousness, cf. J. M. Baldwin, "Thought and Things," Vol. II., Chapter III., on "Common Acceptance and Acknowledgment."
§ 2. On the historically developed doctrine of the 'general notion, ' cf. Locke, " Essay Concerning Human Understanding," Book III., Chajiter III., §§ 6 fif., Berkeley, "Principles of Human Knowledge," Introduction, §§ 6-20; also, T. Hu.xley, "Hume," p. 112, and AI. W. Calkins, "An Introduction to Psychology," pp. 221 ff.
§3. On conception as 'motor' consciousness, cf. Baldwin, "Mental Development in the Child and Race," pp. 325 ff.; Royce there cited on j). 330; C. H. Judd, Journal of Philosophy, VI., p. 90.
§ 4. According to a recent theory, conception is identical except in function with imagination. That is to say, imagination becomes conception merely I)y virtue of associating similar images. On this view, no characteristic attitude or clement is invohed in conception ; and a given experience is conception, or generalization, not for what it is but for what it does.
A very clear statement of this \new is that of Profes.sor Dickinson Miller {Psycholo(^ical Revinv, Vol. II., pp. 537 ff.). In the opinion of the writer. Dr. Miller is altogether right in this view that the function of conception is the association of similar images, but wrong in the denial of the structurally simple consciousness of generality which distinguishes conception.
bibliographical notes
§ I. On the classification of judgment and reasoning, cf. the text-l^ooks of logic. On the distinction between analytic and synthetic judgments, cf. Kant, Kritik of Pure Reason, Introduction, IV.
pp. 97, 99.
§ 2. On animal reasoning, cf. C. L. Morgan, Animal Life and Intelligence, Chapter IX. (with citations) ; James, The Principles of Psychology, II., pp. 349 ff.; Thomdike, cited p. 356.
§ 3. On the nature of abstraction, cf. M. W. Calkins, An Introduction to Psychology, pp. 224 ff. ; James, Psychology, Brief Course, pp. 248 ff. ; The Principles of Psychology, I., 487 fif., 502 ff.; IL, 332 ff.
§§ 4-5. On the nature and origin of language, and on the language of animals, cf. James, op. cit., II. 356 ff. ; G. J. Romanes, Mental Evolution in Man, pp. 13S ff . ; W. Whitney, Language and the Study of Language, pp. 426 ff. ; article on Phik)logy in Encycl. Brilannica, 9th ed.. Vol. XVIII. , pp. 766 ff. ; Muller and the Science of Language, pp. 9 fif. ; Max Muller, Science of Thought, I., 192 ff. ; Science of Language, I., 404 ff. ; C. L. Morgan, Animal Life and Intelligence, pp. 343 ff.
§ 6. On the relation of language to thought, cf. Muller, Science of Thought, I., pp. 50 ff. ; W. Whitney, Language and the Study of Language, pp. 405 ff. ; Muller and the Science of Language, pp. 26 ff.; H. B. Alexander, Visual Imagery, in Psychol. Review^ 1904, XL, p. 335.
§ I. The term 'object' in the first paragraph of Chapter XI. is used not in the widest possible sense to include myself-asobject (the private, personal object), but to refer to the 'otherthan-myself, ' whether personal or impersonal, external or internal. Cf. pp. 3 flf. and 281, above.
a. the sensationalist theory of stumpf
§ 2. Stumpf distinguishes sharply between pleasantness and unpleasantness (Lust and Unlust) on the one hand and higher feeling (Ajfekl or Gemiilsbevjegimg) on the other. He then describes unpleasantness as pain-sensation and pleasantness as faint form of the sensations of ' itch,' of ' tickle,' etc. This account is based mainly on the following considerations: {a) the alleged invariable unpleasantness of pain; {b) the alleged difliculty of assigning physiological conditions of pleasantness regarded as unsensational; (r) the belief that this account is less complex than other theories. No one of these arguments is undisputed.
BiBLroGRAPHV. — C. Stumpf, Uber Gefuhlsempfindungen, Zeitschr. filr Psychol, und Physiol. XLIV., i flf.; Von Frey, Die Gefuhle, 1894; Bourdon, La sensation de piaisir, Revue philosophique, 1893; SoLLiER, Le mdcanisme dcs Amotions, 1905.
In crilkism of the theory, cf. E. B. Titchf.ner, The Psvcholoji;y of Feeling and .Attention, 1908, Lect. I., passim, and Loot. III.; Max Meyer, The Nervous Correlate of Pleasantness and Unpleasantness, L, Psychological Review, 190S, XV., pp. 205 IT. ; C. H. JonxsTOX in the Psychological Bulletin, 1908, V., pp. 65 flf. 2B 369
Wundt includes in tlie gr()U[) of the affections, or feelings, four elements or (rather classes of elements) coordinate with pleasantness and unpleasantness. These four are: tension and relaxation (S pannung-Losiing) , excitement and quiescence {ErregungBeriiliignng). Relaxation is opposed to tension and quiescence to excitement, as pleasantness is opposed to unpleasantness, so that we have three pairs of opposites, or, as Wundt calls them, 'dimensions' of feeling.
The arguments for this view may be summarized as follows: The Wundtians point out in the first place that emotional states differ, according to common consent, not merely as pleasant and unpleasant, but also as exciting or quieting, straining or relaxing. Both melancholy and terror, for example, are unpleasant emotions, yet the first is quieting, or depressing, while the second is as clearly exciting. This purely introspective argument is verified and supplemented by experiment. Alechsieff, whose experimental study is one of the best and most recent of those put forth by members of the Wundtian school, | stimulated his subjects in such wise as presumably to bring about emotional experiences, and recorded both pulse and breathing, and introspection. The introspective records first (i) clearly indicated the occurrence of straining and relaxing, exciting and depressing emotions; next (2) sometimes asserted the occurrence, in emotional experiences, of elemental consciousness other than sensations, pleasantness and unpleasantness; finally (3) seemed to show that pleasantness or unpleasantness may occur in combination with any one of the four other ' feelings.' In other words, the records indicated that in pleasurable emotion subjects were sometimes in a state of tension, but sometimes relaxed, sometimes excited, and sometimes depressed; and that in unpleasant emotion subjects were now relaxed, now strained, and now excited, again depressed. The objective results
Breatliing
The Wundtian conclusion from both sorts of evidence is the following: Exj^eriences which are thus shown to be, on the one hand, introspectively elemental, distinct, and independently variable and, on the other hand, accompanied by clearly differentiated yet coordinated circulatory and respiratory phenomena, are elements of consciousness belonging in a class together. Therefore tension-relaxation and excitement-quiescence form, with pleasantness-unpleasantness, the enlarged class of the 'feelings (Gefuhle).'
This doctrine has, however, found little favor outside the narrow circle of Wundt's fellow-workers and students. Against the Wundtian arguments from experiment it is rightly urged that the outcome of experiment is far from conclusive in Wundt's favor, and that even experiments undertaken from the same theoretical standpoint as Alechsieflf's issue in results of a very contlicting nature.* In default of experiment we are thrown back on introspection and, on this basis, the writer of this book agrees with the opponents of Wundt that elemental allective elements — or feeling-elements strictly coordinate witli ])leasant-
* Cf. .'\lechsieff, op. cit., p. 175- et al, for admission of the opposing results of experimental investigations of the breathing. For .\lechsieff's attempts at explanation, cf. op. cit., p. 207; also pp. 180-200. For the report of experiments carried on in the Cornell laboratory indicating, in opposition to .■\lcchsieff, that the alleged elements do not vary independently, cf. Hayes and Titchencr, cited below.
ncss and unpleasantness — are not discovered in our emotional experience. Most of these critics attempt to reduce all four of the new 'feelings' to kinassthetic and organic sensations, but, in this reduction, they ignore the introspective testimony of Alechsiefl's subjects, v^^hich has at least the face-value of their own. In the opinion of the writer, the following conclusions are truer to introspection : —
(i) Tension is reducible to attention, or clearness, plus the organic sensations which accompany attention. (The significance of this assertion varies, of course, with one's doctrine of attention.)
(2) Relaxation probably is merely the absence of strain. Alechsiefif himself seems virtually to imply this.* So far as relaxation is a positive experience, it seems to reduce, as Titchener teaches, to organic sensations.
(3) and (4) The case is different with excitement and quiescence {Erregung-Beruhigung). These are complex, not elemental, experiences; and the distinguishing feature of them is neither the organic sensations — though these are present and significant — nor any new kind of feeling, but rather the vivid consciousness of doubtful future or of irrevocable past. In the words of Royce : " we tend to regard with restlessness whatever tendency involves our interest in immediately future changes. The emotions of . . . fear, of hope, of suspense are accordingly especially colored by restless feelings. On the other hand, the feelings of quiescence predominate when . . . we regard the past."
This analysis of the Wundtian theory has led, accordingly, to the conclusion that Wundt is unjustified in his teaching of the two new pairs of feelings coordinate with each other and with pleasantness-unpleasantness. Only one of the four, namely, tension, is either elemental or — in any sense — parallel with pleasantness-unpleasantness. Relaxation, a second of these alleged elements, seems to reduce to bare sensation, where the name does not indicate mere absence of strain. The other two, excitement and quiescence, are, indeed, as the Wundtians insist, un-
elements.
BiBLiOGRAPiiY. Thierseele, 1897; Gefiihl und Bewusstseinsanlage, 1903); N. Alechsieff, Die Grundformen der Gefiihle, Psyclwlogischc Stiidien, III., pp. 156 ff. ; J. Royce, Outlines of Ps}-chology, 1903, pp. 176 ff. ; O. VoGT, Zeitschr. fur. Hypnotismus, VIII., p. 212, 1899 (and other writers cited by Alechsieff and Titchener, op. ciL).
In criticism 0/ the theory: E. B. Titchener, Lectures on Feeling and .Attention, 1908, Lecture IV. ; S. P. Hayes, A Study of the Affective Qualities, I. The Tridimensional Theory of Feeling, American Journal of Psychology, XVII., pp. 358 ff., 1906; J. Orth, Gefiihl und Bewusstseinsanlage, 1903; M. Kelchner, Arc/iiv, V., pp. 107 ff.
§ 3. On the classification of the emotions: cf. A. Bain, Feeling and Will, pp. 71-77, and headings of Chapters V.-X.; H. Hofifding. Outlines of Psychology, VI., B, C, Eng. tr., pp. 233 S.; D. Mercier, Mind, N. S., IX. and X.; Spinoza, Ethics, Part III.; J. Ward, Encyclopaedia Britannica, 9th edition, pp. 67-70. The classification adopted in this book owes most to HofiFding, Mercier, and Spinoza.
§ 4. On the ccsthetic consciousness : cf. Kant, Critique of Judgment, Part I., Book I., especially §§ 1-12; Schopenhauer, The World as Will and Idea, Vol. I., Book III., especially §§ 30-35, 38, 45 ; Vol. II., Supplements to Book III., esp. Chapter 39; Schiller, Uber die iisthetische Erziehung des Menschen, Briefe 12-14, 23 ff. ; H. Marshall, Pain, Pleasure, and .'Esthetics, pp. 1 10 ff. ; T. Lipps, Grundlegung der Aesthetik, H. Munsterberg, The Eternal Values, IX.-X., i)p. 165 ff. ; E. Puffer, The Psychology of Beauty, especially II., III., VIII.; G. Santayana, The Sense of Beauty; P. Stern, Einfiihlung und A.ssociation, in der neueren Aesthetik, Bcitriiqe zur Aesthetik, Hamburg, 1898.
imcntcllcn Aestlietik, Arc/iiv fiir die gesammte PsyclioL, II., 1906, and papers there cited; L. J. Martin, An Experimental Study of Fechner's Principles of Aesthetics, Psychol. Review, May, 1906; R. MacDougail, E. D. Puffer, and R. P. Angier in Harvard Psychol. Studies, I. (1903), pp. 309 ff.
On the sense of humor: C. C. Everett, Poetry, Comedy, and Duty. Th. Lipps, Psychologic d. Komik (includes criticisms of Kraepelin, Vischer, Lotze, Hecker), Philosophische Monatshejtc, XXIV. and XXV.; E. Kraepelin, Zur Psychologic d. Komischen, Phil. Stud., II.; J. Ziegler, Das Komische, Leipzig, 1900.
§ 5. On the relation beticeen physical stimulus and affective consciousness: cf. Kiilpe, op. cit., § 37, Wundt, Grundziige der Physiologischen Psychologic, 11.^, pp. 311 ff.
§ 6. Accounts of the bodily conditions of the affective consciousness are, one and all, avowedly hypothetical. The theory put forward in this book is a sort of composite of certain features of the doctrines of Wundt, Flechsig, and Marshall. Two other doctrines, very recently set forth, may be stated, briefly, in the words of their authors : —
(i) Professor Titchener hazards the guess that the peripheral organs of affection are the free afferent nerve-endings . . . distributed through the various tissues of the body . . . The nervous excitations," he holds, "will vary with the tone of the bodily systems in which they are set up, and that tone can itself vary only in two opposite ways."
(2) Professor Max Meyer argues that " if pleasantness and unpleasantness are different in kind from sensation . . . then the kind of . . . relation between nervous activity and pleasantness and unpleasantness is likely to be ... different." Accordingly he attributes pleasantness and unpleasantness to intensity of nerve current. He supposes that " while the correlate of sensation is the nervous current itself, the correlate of pleasantness and unpleasantness is the increase or decrease of
Bibliography. — Wundt, Grundziigc, 11.', ,558 ff. Grundriss, § 7, 10 a; 15, 2 a; \\. R. Marshall, Pain, Pleasure, and ^.sthetics, csp. Chapter V., § 3; P. I'LECHSIG, Gehirn und Seclc, pp. 89 IT.; II. MuNSTERBERO, Beitragc zur Psychologie, IV., p. 216; M. Meyer, Psychol. Review, 1908, XV., pj). 306 fT. ; E. B. Titciiener, A Text-book of Psychoiog}', 1909, § 74, pp. 260-263.
§ 7. The emphasis upon the occurrence in emotion of sensational constituents — sensations due to heart-beat, dilation of arteries, breathing, and the like — is a contribution to psychology of Profess(jrs William James and K. Lange. Both lay such stress on this factor of emotion that they tend to underestimate or even to ignore the other structural constituents of emotion — the pleasantness or unpleasantness. It should be noted that this James-Lange doctrine stands in close relation to the conception of emotion as doubly personal. I'^or precisely organic sensation is an important sensational factor in my consciousness of myself; and kinitsthetic sensations of movement — of approach and withdrawal, cooperation, and antagonism — are at least constituents of my. consciousness of other selves.
Bibliography. — Cf. James, IVinripies of Psychology, Chapter XXV. (Briefer Psychology, Chapter XXIV.); The Physical Basis of Emotion, Psychol. Rci'icw, I., pp. 516 IT.; Ea.vge, Uber Gemiitsbcweguni!;en, (ransiatcd by II. Kurella, Eeipzig, 1887; C. Stumpk, Uber den Hegriff der Gemiitsbewegung, Zcilschr. fur Psvchol. und Physiol., XXI., pp. 47 ff.
§ 8. Besides the reports (cited al)o\e, in jlj 3, j). 371) of experiments on affective reactions, the following reports of earlier experiments may be consulted : —
In favor of the doctrine that affective reactions niav be dearly distinguished as pleasant or unpleasant: IVre, .Sensation et Mouvement, Pari^, 1S.S7; .-\. Lehmann, Hau|)tgesetze des menschlichen Gefuhlslebens, Ger. tr., Lei[)zig, iS()j, and Die kir-
In opposition to the doctrine: Binet et Courtier, UAnnee Psychologique, 1897, Binet et Henri, ibid.; J. R. Angell and H. B. Thompson, Organic Processes and Colisciousness, Psychol. Review, 1899, Vol. VI., pp. 32 ff. (wdtli full references) ; E. A. Gamble, Attention and Thoracic Breathing, Amer. J own. of Psychol., 1905. The criticism based on these experiments is strengthened by many observations; for example, by observation of the warm flush of shame, one of the unpleasant emotions.
§ 9. On the biological significance of emotion: cf. Darwin, The Expression of the Emotions; Spencer, The Principles of Psychology, Vol. I., Part II., §§ 122 ff.; Vol. II., Part IX., §§ 497 ff.; James, The Principles of Psychology, Vol. II., pp. 477 ff.; J. Dewey, Psychol. Review, 1894, I., pp. 553 ff. ; II., pp. 13 ff. ; G. Dumas, Revue Philosophiquc, LVIIL, LIX. (reviewed, Psychol. Bulletin, 1907, IV., pp. 222 ff.) ; D. C. Nadejde, Die biologische Theorie der Lust und Unlust, 1908.
§ I. In support of the teaching, contrary to that of this book, that there is a volition or conation element, cf. G. T. Ladd, Psychology, Descriptive and Explanatory, 1895, pj). 211 flf.
Readers of my earlier book, "An Introduction to Psychology," will notice that I have abandoned the use of the term 'volitit)n' to designate exclusively the anticii)atory image regarded from the standpoint of the idea-psychologist. In this book volition is used as a synonym for 'will.'
§ 2. Professor Thomdike oppo.ses the conception of volition as anticipatory imagination on the ground that actions may be, and often are, performed without any antecedent image of them. "Any mental state whatever," he says, "may be an impulse, — may take on the aspect of impeller to an act" ;* and he adds that "percepts, sensations, and emotions" more than "images and memories" impel action.* All this, doubtless, is true. Professor Thorndike rightly suggests that even an exhortation to choice, such as "Make up your mind," may in actual fact result in an impulsive act and not in an act preceded by antici{)atory image. Yet it does not follow that because an act may be impulsively performed, therefore volition is identical with impulse. The truth is that there are two sorts of ideo-motor act : the more common impulsive movement which Thorndike describes, and the strictly voluntary act. A given action may be performed either impulsively or voluntarily — either without, or witli, anticipatory consciousness.
On the feelings of realness: cf. A. Bain, Emotions and Will, pp. 510 £f. ; W. James (cited, p. 235); J. M. Baldwin, Handbook of Psychology, Vol. II., Peeling and Will, Chapter VII., pp. 148 ff. (with authors there cited) ; Th. Lipps, Leitfaden der Psychologic, 1903, pp. 156 ff.
On faith: cf. Baldwin, op. cit., p. 158,3; J. Royce, The Philosophy of Loyalty, 1908; H. S. Holland, "Faith," in Lux Mundi, ed. by C. L. Gore, pp. 1-54.
On the social consriousness: cf. G. Tarde, Social Laws, translated by H. C. Warren, 1899; J. M. Baldwin, Social and Ethical Interpretations, 1897, 1906; E. A. Ross, Social Psychology, 1908; H. C. Cooley, Social Organization, A Study in the Larger Mind, 1909; W. McDougall, An Introduction to Social Psychology, 1909; G. H. Mead, Social Psychology as Countermart to Physiological Psychology, Psychol. Bulletin, 1909, VI., pp. 401 fif.
On imitation and opposition: cf. G. Tarde, Les lois de I'imitation; G. Le Bon, The Psychology of the Crowd; J. Royce, Preliminary Report on Imitation, Psychol. Review, 1895, II., pp. 217 ff. ; The Psychology of Invention, ibid., 1898, pp. 113 ff.
§ I. The scientific study of personal relations forms the most important problem of what Professor Stern calls ' psychography, ' the study of individual selves. In the effort to coordinate such studies, the I nstitut/ur angeicandte Psychologic has appointed a special commission (cf. Zeilschrift fiir angeicandte Psydiologie, III., Heft. 3).
§ 2. Most of the current conceptions of religion are defective for one of two reasons: (i) Some of them are so wide that they do not servo to distinguish religion from other forms ot immaterialism. So, when Wundt says, "All ideas and feelings are religious which refer to an ideal existence," an existence which fully corresponds to the wishes and requirements of the human mind,* he does not sufficiently distinguish religion from j)ersonal desire or from moral striving. (2) Over against these inclusive conceptions are those which unduly narrow the concejjtion of religion. Thus, Schleiermacher makes of religion an exclusively emotional experience when he defines it as "a feeling of absolute dejiendence upon God." t .\nd, on the other hand, Herbert Spencer confuses theology with religion, that is, ])hilosophy with experience, when he conceives religion as "the recognition of a mystery pressing for interpretation." J In opposition to these one-sided views: Professor Leuba's words deserve quotation ; i^ Religion, he says, is "coml)ounded of will, thought, and feeling, bearing to each other the relation which belongs to them in every department of life."
§ "The Psychological Nature of Religion," .•l»/CT*/<-(7«y<>/<r;/(;/ of Theology, January, 1907, p. 80, and "The Psychological Nature and Origin of Religion," 1909, p. 8. (.Note the citations of the footnotes.)
Many writers dissent from the teaching of Chapter XV. that the object of the rcHgious consciousness always is personal. Professor Leuba, for examj)le, recognizes the 'godless' as well as the ' personal ' religions, though he lays stress on " the significant fact that until recently every existing historical religion was a worship of a personal divinity." In the opinion of the writer, one not only conforms to this historical usage, but one suitably distinguishes a clearly marked experience by limiting the term to the conscious relation of self to self.
Barely incidental reference has been made, in this book, to an important branch of psychology — the study of abnormal forms of consciousness. The neglect has been, it must be admitted, intentional. The 'abnormal' is simply that which diverges from the normal, and must therefore be studied from the standpoint of the normal consciousness. Obviously sucli a study can be undertaken only after one has concerned oneself with the facts and jjrinciplcs of normal psychology.
This closing section will speak briefly of certain of the more important phenomena and forms of the abnormal consciousness — discussing, however, only non-pathological e.xperiences and leaving out of account all forms of insanity, the abnormal consciousness due to cerebral disease. The abnormal phenomena to be considered are, in the main, the following: (i) perceptual hallucinations and illusions; (2) abnormal motor phenomena, usually 'known as automatisms; (3) abnormal suggestibility; and (4) abnormal dissociation. .A.ll these e.xperiences occur in dreams, in hypnosis also, and in tiie waking life as well. We shall, tlierefore, first brielly study our dreams, shall next consider the state of hypnosis, and shall then discuss the abnormal experiences of our waking life. A final section will l)e devoted to a consideration of the veridical phenomena alleged to occur in all these states.
The essential likeness of the dream consciousness and the waking consciousness should first he noted, for it is often overlooked. All sorts and kinds of consciousness occur in dreams. A structural analysis will disclose not only visual and auditory, cutaneous, olfactory, and gustatory sensational consciousness, but affective and relational consciousness as well. It is indeed admitted on all hands that people remember and feel in their dreams. It is equally true, though more often disputed, that they think and reason and choose, though choice and reasoning are based on absurd premises leading to impossible outcomes. |
Yet, spite of the likeness of dreams to the waking consciousness, dreaming is characterized by three, at least, of the four abnormal phenomena which have been named, (i) The distinguishing mark of every dream is the fact that it is essentially hallucination or illusion. % In my dreams I externalize unreal people and faraway scenes and impossible situations. The hallucination (or illusion) is doubtless due to the dissociation to which reference will presently be made. It remains uncorrected because of the lack of perceptual and habitual images with which to compare dream images. In the daytime the tendency to externalize vivid images is corrected by the incongruity of the image with the perceptual experience : the imagined apple tree in bloom cannot well form a part of the perceived winter scene. When, on the other hand, I am asleep with eyes closed, nothing contradicts the externality of the vivid image.
(2) Dreams may be, in the second place, accompanied by motor reactions which, after waking, one is unaware of having made. Many people speak during their sleep — in all probabiHty while they are dreaming; and sleep-walking is no uncommon occurrence. Such bodily 'automatisms,' of which the waking self is
sleep.
(3) Closely coiincrlcd with the liallurination is the dissix iatioii involved in our dreaming. By dissociation is meant the interruption of ordinary habitual associations, the abnormal narrowing of our experience through the dropping out of images and memories which are normally present in the waking life. Such a narrowing of the ordinary consciousness has one (sometimes both) of two results. Either the remaining consciousness is more intense, or else other, more remote, imaginings take the place of those which have dropped out. The greater vividness oi fewer objects is an explanation of the dream hallucination; the occurrence of unusual imagery characterizes most dreams. On its neural side, dissociation implies what may be described, somewhat figuratively, as a blocking of ordinary 'association paths' and a consequent damming up of cortical energy. This results on the one hand in the more intense functioning of the sense centres still excited, and on the other hand in the spread of the cortical energy through less frequently used 'brain paths.'
It must, however, be noted that dreaming is not purely dissociative. On the contrary, dreams are connected in two ways with the waking life: they are due to past waking experience and they are. remembered after waking. As regards the first point, most dreams can be traced associatively to a starting-point in the waking life; and sonv^' dreams even include s{)ecilic memories of waking experience. Out of 194 of my own dreams, carefully studied, I found only 22 (11.3 per cent) in which I could trace no suggestion from the waking experience. Profes.sor Sigismund Freud believes that the relati(,)n of dream to previous life is always emotional — that every dream is, in fact, a wish fulfilled.* In my
* " Die Traunideutung," igoo, igoq. Dr. Freud offers as proof the carefully analyzed and valuable records of many dreams, mainly his own. Unquestionably he shows that many dreams may reasonably be explained as fulfilments of wish. He does not, however, — in the nature of the case, he cannot, — show that all dreams correspond to actual wishes; indeed, he does not, in the opinion of many critics, successfully exclude the possibility that some of his own dreams might be otherwise explained.
is undeniable.
Besides this connection with the previous life, dreams, as already stated, play a role in later experience. We often remember our dreams; and are sometimes puzzled to know whether we have really experienced or dreamed some event. And yet, notwithstanding the connection of dream with waking life, dreams are also markedly dissociative, cut off from the ordinary waking consciousness. Thus, the dream self commonly adjusts himself without surprise to changed surroundings; he fails to imagine names and scenes which in waking life would certainly be suggested to him ; and he may even forget his name and circumstances and take to himself a new set of characters.
b. Hypnosis
By hypnosis is meant a state in which one is abnormally influenced by one person's suggestions and abnormally unaffected by any suggestions of an opposite sort. Hypnosis is induced in various ways, as by 'rhythmic passes,' or by fixing the attention of the subject on a bright surface ; but all these methods agree in directing the attention of the subject upon the hypnotizer and in diverting his attention from other objects. The hypnotic subject is deaf and blind to all that goes on about him, but keenly aUve to every look, word, and movement of the hypnotizer.* In a word, hypnosis consists in abnormal suggestibility in a single direction, coupled with extreme dissociation — the dropping out of memories, images, and even perceptions which would normally be present.
The suggestion of the hypnotizer may affect both the bodily reactions and the consciousness of his subject; that is, he may bring about both automatisms and hallucinations. There are two main forms of bodily control. In the lighter stages the
hypnotizer affects, positively or negatively, the voluntary muscles of his subject, preventing him, by a command, from opening his eyes or inducing him to hold his arm outward and rigid for minutes at a time. More complicated acts may also ije brought about : for instance, the subject may lift books from a table or may whirl several times round. In deeper hypnosis the involuntary muscle contractions, and thus the pulse and the secretions, may be affected. Structural bodily changes sometimes occur. There are, for example, well authenticated though infrequent cases, in which blisters have been produced by a hypnotizer who assured his subject that a burning object would be applied to his skin. We may quote, in illustration, from Krafft Ebing's account of
with the percussion hammer a cross on the skin over the biceps of the left arm, and suggests to the patient that on the following day at twelve o'clock, in the same place, a red cross shall appear. . . . On the next day at eleven o'clock . . . the patient wonders that she has an itching, excoriated spot on her right upper arm. . . . The examination shows that a red cross is to be seen on the right arm exactly at the place corresponding with that marked on the left side yesterday." Later a 'sharply defined scab' is formed.* Hypnosis is marked, fmally, by perceptual illusions and hallucinations. These may be positive or negative. A positive illusion may, for example, be induced if the hypnotizer, pointing to cracks in the wall, tells the subject that these arc interlacing tree tops, thus suggesting the vision of a summer landscape. Or the hypnotizer may hand to his subject a cup of water, or even of ink, telling him that it is coffee. Indeed, the alleged coffee may produce actual bodily effects, a flushed face, for example. These, of course, are instances of illusion brought about by means of an external object. Genuine hallu-
cinations can also l)c induced: a subject, for example, will hear the sounds of a piano if they are merely suggested by the hypnotist. The negative illusions and hallucinations of the hypnotized subfeet are far more diftkult of explanation. The hypnotizer, for example, indicates some jjerson who is present, and says decidedly, "This man has left the room; he is no longer present." Forthwith the hypnotized subject utterly disregards the banished individual, faiUng to reply to his cjuestions, and even running against him. In like manner, the hypnotizer may suggest to his subject that he is unable to see or to hear or to feel pain. Pain-sensations are not, however, very suspectible to suggestion, and the value of hypnotism as an anaesthetic has been very much exaggerated.
It has thus been shown that hypnosis is characterized by suggestibility, automatism, hallucination, and dissociation. In its extreme forms the dissociation and the new set of imaginings which replace the old seem to involve a loss of the normal personality and a transformation into a new self. Thus, the deeply hypnotized subject, if told that he is Paderewski, talks about music and devotes himself to the piano. Krafft Ebing's subject, lima
played contentedly for hours at a time with a d()ll, wrote an unformed hand, and made childish errors in spelling words which she normally spelled correctly. The new personality may persist for a long period and recur regularly. One of the best-known cases is that of Janet's patient, Leonie,* who " has been hypnotized by all sorts of persons from the age of sixteen upwards. Whilst her normal Hfe developed in one way in the midst of her poor country surroundings, her second life was passed in drawingrooms and doctors' offices, and naturally took an entirely dififerent direction. In her normal state, this poor peasant woman is a serious and rather sad person, calm and slow, very mild with every one, and extremely timid; to look at her one would never suspect the personage which she contains. But hardly is she put to sleep
Ab nor null Psychology 387
liy[)iK)tically, when a metamorphosis ociurs. She is gay, noisy, restless, sometimes insuj)jK)rtably so. She remains good-natured, hut has ac((uired a singuhir tendency to irony and sliarj) jesting. To this charai ter must be added the possession of an enormous number of recollections, whose existence she does not even suspect when awake, for her amnesia is then complete. . . . She refuses the name of Leonie, and takes that of Leontine (Leonie 2) to which her first magnetizers had accustomed her. 'That good woman is not myself,' she says, 'she is too stupid!' To herself, Leontine or Leonie 2, she attributes all the sensations and all the actions; in a word, all the conscious experiences which she has undergt)ne in somnambulism, and knits them together to make the history of her already long life. To Leonie i [as M. Janet calls the waking woman], on the other hand, she exclusively ascri!)es the events lived through in waking hours. But it is the same with her second or deepest state of trance. When after the renewed passes, syncope, etc., she reaches the condition called Leonie 3, she is another person still. Serious and grave, instead of being a restless child, she speaks slowly and moves but little. Again she separates herself from the waking Leonie i. And she also separates herself from Leonie 2 : ' How can you see anything of me in that crazy creature?' she says. 'Fortunately, I am nothing for her.' " The dissociation of hypnosis from the waking hfe is evidently not complete. The hypnotized subject remembers not only the events of former hypnosis but facts of his waking life. On the other hand, unlike the dreamer, he seldom remembers, after waking, the experiences of the trance. Yet hypnosis, in its deeper stages, has a curious influence on the later waking life, known as post-hypnotic suggestion. The hypnotist, for example, before waking his subject, addresses him in some such fashion as the following: "To-morrow, at twelve o'cK)ck, you will stop the clock on the stairs." At twelve o'clock on the following day, the subject, apparently in his normal condition, actually stops the clock, to all appearance on his own initiative, witiiout remembering the suggestion of the hypnotist.
It is obvious that the main value, as well as the chief danger, of hypnotism lies in just this susceptibility of the hypnotic subject to post-hypnotic suggestion. Physicians and 'mental healers' who make use of hypnotism suggest to the patient that he is freed from disturbing symptoms, and that he will remain freed from them after waking. Not merely nervous diseases, so called, but all diseases and .symptoms which have no anatomical cause have been successfully treated by hypnotism.
In unscrupulous hands the ability to give post-hypnotic suggestions may, of course, be grossly abused. There are reasonably well-attested instances of crimes committed and of large sums of money given away, in accordance with post-hypnotic suggestion. In such cases the discovery of the guilty hypnotist is made difficult by the fact, already indicated, that the hy{)notized subject so seldom remembers the events of the hypnotic state. The best authorities, however, agree in the conclusion that only individuals predisposed to criminal acts can be influenced to actual crime.
It should be stated very emphatically that no person can be hypnotized against his will. Hypnosis is induced only when the attention is concentrated on the hypnotizer. On the other hand, the habit of yielding attention, like all other habits, is readily formed. It follows that a person several times hypnotized becomes very readily susceptible. Evidently there is grave danger in a tendency to yield oneself to the exclusive control of others. For these reasons the hypnotic state should be induced only for serious purposes — to cure disease or to extend knowledge ; and only j)ersons possessed at once of medical and of psychological training should give hypnotic suggestions.
c. Abnormal Experiences in the Waking Life
(i) There are countless authentic illustrations of waking hallucinations and illusions. The voices which called to Joan of Arc, the devil who used to argue with Luther, and the daimon of Sokrates are illustrations which at once suggest themselves. It is not always easy to decide, from the descriptions which we have of them,
wlicthcr tlicsc visions arc illusions, that is, conditioned in |)art l)y |)C"ri|jiicral t-xcitation, or whctluT t!iey arc hallucinations, that is, conditioned by cerebral excitation only. Sometimes, however, the distinction is obvious. For example, the phantoms which haunted Charles IX. after the massacre of St. Bartholomew were hallucinations, but the image of Byron which appeared to Sir Walter Scott was a mere illusion, for the clothes of the figure consisted. Sir Walter discovered, of the folds of a curtain.
Far more important as materials for study than these vivid, yet often confused and unverified, stories from which we have (juoted, are the massed results of an International Census on Wakinf^ Hallucinations, made by the Society for Psychical Research.* The question on which this study is based is the following : '' Have you ever, when believing yourself to be completely awake, had a vivid impression of seeing or being touched by a living being or inanimate object, or of hearing a voice, which impression, so far as you could discover, was not due to any external physical cause? " To this question, 27,329 answers were given, and of these, 3271, or 1 1 .96 per cent, were affirmative ; in other words, one out of every twelve of the persons reached by the investigation asserted that he had experienced hallucinations. This percentage, however, is, in all probability, too high to be representative, for the larger the number of answers received by any one collector of these statistics, the smaller was the number of affirmative replies. It follows that if the investigation were further extended, the percentage would probably fall still lower.f Yet, with all allowances for overestimation, the fact remains that waking hallucinations must be commoner than many of us think. Visual hallucinations far outnumber the others: of 2232 cases completely described, 144 1 included visual elements, 850 were partly auditory, and only 244 were tactile. Most of the.sc hallucinations related to people, living or dead, but a few represented angels or supernatural beings, and a slightly larger number were grotesque or horrible figures. About
390 Hallucinations
onc-twcnlic'lli of them were indefinite or indesrrihahlc. Persons between the ages of fifteen and thirty reported more than one-half the number of these illusions and hallucinations, and men reported only two-tliirds as many as women, 9.75 per cent as compared with 14.56 per cent. The general conclusion of the Report is " that this apparent difference should, to a great extent, be attributed to the fact that men, among the pressing interests and occupations of their lives, forget these experiences sooner."*
Besides the involuntary hallucinations and illusions, there is the whole class of illusions which are voluntarily induced. These may be regarded as cases of self-hypnotization. The commonest method of bringing about illusions is known as crystal vision : the experimenter looks fixedly at a glass sphere, at a mirror surface, or even at a glass of water, until there appear pictures in its reflecting surface. The images which appear within these different crystals are usually reproductions of former experiences, and often of longforgotten objects or scenes. One sees, for instance, a forgotten name or a room familiar in early childhood. The images, on the other hand, may be purely imaginary, as when Mrs. Verrall sees in her crystal t colors so vivid that they leave an after-image in complementar}' colors. The images seen in crystals may be, finally, veridical images of actual scenes beyond the range of the normal vision of the crystal seer, f
The phenomena of syna^thesia, of which the most important are so-called 'colored hearing' and 'mental forms,' are sometimes regarded as waking illusions. Colored hearing consists in the regular sequence of a consciousness of some particular color upon the consciousness of a letter, a name, or a musical tone. A mental form is a regularly recurring imaged arrangement of serial terms — numerals, for example, or names of the months of the year — in some special form, perhaps in a circle or in a zigzag line. But these are, in great part at least, cases of vividly associated images, not illusions.
(2) Not only hy|)n()tic and hysteric sul)jais, hut many well and apparently normal [)eoj)le, exhibit the phenomena of aulomatism, that is, relatively complex bodily movement executed without the knowledge, or at least without the after-memory, of the normal waking self. The best-known form of automatism is automatic writing, and is of the following nature:''' the subject provided witli a pencil, and so placed that the hand which holds the })encil is hidden from his eyes, unconsciously responds to stimulation of the hand. If the hand be pressed three times, it will make three marks when these pressures are over; if the hand is guided and made to draw a single letter, it may go on to complete a word. Normal persons possess the rudiments of automatic writing, passively repeating uniform movements when the experimenter has initiated them, following the rhythm of a metronome, or even outlining imagined figures, and writing imagined names. The significant feature of this experience is the subject's entire unconsciousness of the movements of his own hands.
(3) In the waking life, as in dreaming and in hyjinosis, dissociation, that is, the loss of the old memories of the normal life, sometimes seems to involve a so-called loss of personality ; and the new complexes of imagination which replace the old seem to make up a new personality or self. Often the two personalities alternate; sometimes the new one supplants the old. An early instance is that of Ansel Bourne, a Rhode Island carpenter who disappeared in January, 1SS7, just after drawing live hundred dollars from a bank. In March of the same year a man who called himself Brown, and who, for six weeks, had been intelligently carrying on a small fruit and candy store in Norristown, Pennsylvania, waked as .\nsel Bourne, in frightened ignorance of his surroundings.!
A more recent and more conlplicated case is that of Dr. Prince's neurasthenic |)atient, Miss Bcaut hamp, who comes to herself after longer or shorter periods of forgetfulness to lind that she has done
392 Loss of Personality
suqirising things — broken a])p()intments or walked unheard-of distances, that she is in strange situations, wound round and round and tangled in yards of worsted, for example. Sometimes she finds before her a note written to herself in her own handwriting, and on her own notepaper, puq^orting to come from another self which has taken the walks, broken the apjjointments, involved her in difficulties.*
II. THE EXPLANATION
The most common exj)lanation, nowadays advanced, for abnormal phenomena of consciousness, is the hypothesis, already suggested, of secondary selves, or personalities. Such a secondary self is variously known as sub-conscious or co-conscious, as subliminal or supra-liminal. It is conceived as a self other than the ordinary waking self, yet in some way connected with it. There may be several of these alternating secondary selves. Dr. Prince, for example, believes that the facts of Miss Beauchamp's case can be explained only by the hypothesis of six distinct personalities, one of whom — the mischievous Sally who writes the notes and tangles her alter ego in the yarn — is entirely antagonistic to the main self. This hypothesis is believed to be necessary to account for the extreme forms of dissociation just illustrated; and the theory is then often extended to apply to other abnormal phenomena. Thus, on such a theory, the dreaming self, or the hypnotized self, or the self who sees figures in the crystal, is the sub-conscious or co-conscious self.
There is no time to discuss in detail the complicated issues involved in such a theory. The following comments are, therefore, dogmatically stated, though they run counter to the view of many psychologists: The majority of so-called abnormal phenomena are perfectly well explained without recourse to a secondary self hypothesis. It has appeared already that dream illusions are the natural result of the dissociation natural in sleep. It is likewise obvious that abnormal automatisms are extreme instances of the natural outcome of consciousness in action, and of the anatomical unity of afferent and efferent processes. Hypnosis, also, strik-
ingly as it dilTcrs from the waking state is, after all, essentially an exaggerated form of the suggestibility which makes everybody, at least on occasions, imitate slavishly some dominating self. Upholders of the subliminal self theory often admit the theoretical possibility of explaining many phenomena of dreams, hypnosis, and automatism, by analogy with the normal waking consciousness. They argue, however, that other facts, in particular, many j)henomcna of dissociation, require a secondary self hyjiothesis; and that continuity requires the explanation of all al)normal phenomena by the hypothesis essential to the explanation of this one group of them. This application of the principle of continuity is not beyond cavil ; but it is more important to question the premise of the argument. The writer of this book believes, with many psychologists, that the phenomena of dissociation, even the most {)ronounced of them, have not been shown to differ, ultimately, from the tluctuations of mood and the alternations of memory of so-called normal experience. I am elated to-day, to-morrow depressed ; I am living to-day with the memories of my summer in the woods ; to-morrow I have forgotten the very name of my forest retreat and am immersed in my workshop and its associations. The complete change of mood, the more absolute loss of niemor)-, are but extreme forms of this normal dissociation.
To state this differently: what I call my normal experience is a complex web woven of many strands of memory, that is, of scries of connected images, each series distinct from the others; it is a composite of many distinct grou|)s of interest and preoccupation. I may regard these memory series and these varying circles of interest as aspects of myself, or as partial selves, distinguishing, for instance, my professional from my personal self, my business from my family self or, perhai)s, my frivolous from my strenuous self. So-called dissociation of self involves (lie i)eculiar ])rominence of some one of these lesser selves, or aspects of myself, coupled with unusual forgetfulness of all that lies outside this circle of interest and memor\'. But whether or not the 'secondary selves' of the abnormal consciousness differ in kind or in degree from the partial selves, with their (li>tiiKt
In the first place, the term 'subconscious' must not be taken as referring to a mysterious something neither conscious nor unconscious. There is no such middle term between the two: what is not conscious is unconscious. By ' subconscious' should be meant, therefore, either the unconscious physiological process or the inattentive consciousness. In both senses of the term, ' the subconscious, ' so far from being occult or mysterious, plays an important part in the normal experience.* On the one hand, all sorts of muscular reactions are performed subconsciously, that is, through unconscious reflexes, and one finds to one's surprise that one has already wound one's watch, or one goes to the front door only to find that one has already locked it. And, similarly each one of us is at every instant 'subconsciously,' or inattentively, aware of a multitude of facts in the environment — of the visual objects which do not excite the visual centre, of faint sounds or odors. The outcome of the inattentive perception is, not infrequently, an apparently sudden and unaccounted for image of name or date or event which one does not remember that one has ever ^vitnessed or heard.*
It must be insisted, second, that the dissociations of personality never involve, what they are sometimes said to imply, a loss of personality. This will be admitted by those of us who sometimes experience a doubling of the dream-personality. I dream, for example, of watching at my own sick-bed, and always I am identified ^vith one, if not both, these selves. And no matter what the hypnotic self forgets, the I-which-forgets remains.
It should be noted, in conclusion, that the secondary self — in the extreme cases of changed personality — might be conceived not as an alternating or partial self, but as a self totally distinct from the normal self, though connected ^\^th the same body. This is an older view, yet it has modern support. f
Reference must be made, in conclusion, to so-called veridical phenomena — experiences of people, events, or things, which are beyond the limit of the normal observation or communication. Prophetic dreams, clairvoyant visions, mcdiumistic revelations, are the phenomena most commonly grouped under this head. It should be noticed, first of all, that peoj)le arc very readily mistaken in attributing a veridical character to their experiences. Nothing is more common than the false impression, after an important event, that one has [previously experienced it. Just as places seem familiar to us, when we have never seen them before, so we meet events, especially ovenvhelming ones, with a curious sense of having always known or expected them. More than this, veridical experiences may be due to information normally acquired, but forgotten. For example, Mrs. Holland's automatic reproduction of Mr. Myers's epitaph may be due not to the fact that the si)irit of Mr. Myers is speaking through her, but to the fact that, though she has no memory of the epitaph, she has read parts of his autobiography.* It is, however, believed by careful students that many veridical phenomena are incapable of explanation, either through coincidence or through forgotten normal ex|)eriences, and that they presuppose an intluence of self by self through other than the usual means of language and bodily e.xpression. Such supranormal communication between living persons is named telepathy, or thought-transference; and it is held by some that it may have a physical basis — ethereal vil^rations of extreme minuteness due to changes in one brain and resulting in changes in another. f .Alleged instances of tclcj)athy are either spontaneous or ex])erimentally induced. Under the first head may be reckoned, in the first place, the ordinary cases in wliich p(.'<)|)lc who know each other well
t Cf. Podmorc, "The Naturalization of the Supt-rnatural," pp. lo ff., and note his remark: "No such coiincitioii between thinking brains has been proved," and his statement (p. 12) of the main objection to the hypothesis: the difficulty of conceiving such vibrations to be effective at a distance.
396 Veridical Phenomena
make the same remark at the same instant, or respond, as we say, to unspoken questions. More impressive are the cases in which figures of absent people appear in dress and surroundings corresponding, as afterward discovered, with their position and surroundings at the time of the 'vision' or 'message.' Thus, Ca[)tain Beaumont, in London, rises to greet his wife, who is wearing a * mauve dress,' which he has never seen, at a moment when she, in Tenby, is speaking to friends of his absence.* Far more important, evidently, than the accounts of these 'spontaneous' cases are the records of experiments in thought-transference. The most important of these were carried out, in 1889-1891, under the direction of Professor and Mrs. Sidgwick and of Miss Johnson. In 90 out of 617 cases one numeral, out of 81 possible, was intently fixated by the experimenter and correctly stated by the subject of the experiment, who was so placed that he could not see the numerals. By chance alone, only 8 correct statements would, presumably, have been made. The number of correct statements is reduced when subject and experimenter are in different rooms, yet is still too large to be attributed merely to chance. There are also a few cases in which one person, at an hour previously set, draws diagrams or fixates an object which (in one instance four times out of ten) is reproduced or distinctly imagined by a person far distant. f Similar communications, many people hold, are made to living persons by those who have died. The evidences brought forward for this conclusion are mainly (i) the occurrence of clairvoyant visions concerned with death ; and (2) alleged communications, through mediums, from the dead. One may quote, in illustration of the first sort of evidence, the authenticated story { of Captain Colt, an officer of the British army, who had a vision on the eighth of September, 1855, of the kneeling image of his brother, a soldier who was then before Sebastopol. The figure had a wound on the
right temple. Captain ('(tit dcscrihed the vision to the inemhers of his household, and both his accounts of it and his statement of the date are substantially corroborated by his sister. A fortnight later he had news of his brother's death on the eighth of September. His brother's body had been found ''in a sort of kneeling posture . . . prop[)cd up by other bodies, and the death wound was where it had appeared in the vision." It is clear, however, that such cases do not necessarily involve communication with the dead, since one may suppose a telepathic message from living witnesses. The evidence from alleged mediumistic revelations presents greater complexity. On the one hand, it is agreed on all hands that the great bulk of the abnormal physical phenomena popularly attributed to spirit inlluence — the table-tipping, phosphorescent lights, fragrances, and sounds — are due either to automatic movements unconsciously performed by the mediums, or to their fraudulently concealed bodily movements, sleight-of-hand performances and mechanical devices. Records of the exposures of alleged mediums furnish accumulating and incontestable evidence of these statements. On the other hand, several investigators, foremost in the exposure of these spiritualistic frauds, hold that there are instances of revelations through mediums which may be explained only as the direct communion of the dead with the living. Such is the communication said to be made through the medium, Mrs. Piper, to Sir Oliver Lodge by an uncle long dead, who related occurrences known only to one living person who was miles away and unaware of the 'seance' with Mrs. Piper.* More important is the evidence furnished in very recent years by the phenomena of cross-correspondence in which one automatist is impelled to write statements unintelligible to her, which arc later understood through statements, by themselves equally unintelligible, written by another automatist. So, certain Latin passages written automatically by Mrs. Verrall on March 2, 4, and 5, 1906, were a riddle to her until the words "Ave Roma immortalis," written at a distance, on March 7, by
* Proceedings of the Society for Psychical Research, VI., pp. 458 IT. Cf. also the records of Mrs. Piper's sittings with the friends of G. P., ibid., XIII. See Podniore, op. cit., pp. 319 IT.
Mrs. Holland, clearly rrlVrred the descrij)tions to Rome and to a picture !)y Ra])hael. The picture was well known to Mr. Myers, who — in the belief of Mrs. Verrall, Mrs. Holland, and others — is controlling their automatic writings.
Tliree scientific attitudes toward this evidence are possible. A grou|) of trained investigators, including the late Professor Sidgwick, the late Mr. F. W. H. Myers, Mrs. Sidgwick, and many others, believe that there is at least preponderant evidence of "direct supersensuous communication of mind with mind,"* and that this communion is not only between the living, but of dead with living. It should be added that even those who accept, more or less definitely, this conclusion do not assume to understand the nature and, above all, the strange limitation of the communication; that they do not claim to offer a positive estimate of the value of the messages or to interpret their meaning. At most they hold that the fact of the communication is established. (2) Another group of psychologists includes some who admit that the "theory which assigns" the phenomena oi cross-correspondence " to a controlling intelligence external to either of the two automatists must rank, prima facie, as a good scientific hypothesis." f Yet these students hold that the "evidence . . . strong as it is, is inconclusive." J Among these men who value the evidence on which the spiritistic hypothesis is based, while yet they reject spiritism, are those who accept the hypothesis of telepathy, supranormal communion among the living. Mr. Frank Podmore is prominent in this group. (3) To a third group of psychologists, when "the question is . . . whether departed spirits enter into communication with living men by mediums . . . the scientist does not admit a compromise; ... he flatly denies the possibility . . . the facts as they are claimed do not exist and never will exist." § Even so-called telepathic communications between the lixing are, for these critics, explicable through un-
intended suggestions — for example, through 'involuntary whispering,'* or else the alleged communications only aciidentally or superficially resemhle the originals.
In the face of this divergence t)f o])inion, the duty of the layman is fairly clear. He will l)e theoretii:ally open-mindetl, neither accrediting nor rejecting, uncritically, evidence brought forward on either side. But remembering the proved frauds in mediumistic revelations, and the disagreements among experts, and noting the admitted ignorance concerning the nature and value of alleged veridical phenomena, he will never direct his own conduct by consulting mediums, inter[)reting dreams, gazing into crystals, or playing with planchettes and ouija-boards.
For Bibliography on abnormal psychology, cf. the citations of the footnotes, and add: On dreams, M. W. Calkins, Statistics of Dreams, American Journal of Psychology, 1893, V., pp. 311 ff. ; Sante de Sanctis, I Sogni, 1899. On telepathy, Frank Podmore, .\pparitions and Thoughttransference, 1897. Also Joseph Jastrow, Fact and Falile in Psychology, 1901; F. W. Myers, The Subliminal Self, Proceedings of the Society for Psychical Research, \'II., \'II1., IX.; li. Munsterberg, Pyschotherapy, 1909.
* Cf. Hannsen and Lchmann, Philos. Stndieu, XT., pp. 471 ff., reviewed hy W. James, Psychol. Re^'icu; III., p. q8; answered by H. Sidgwick, Proceedings of the Society for Psychical Research, XII., p. 298.
Chapter II. i. What character of perception is illustrated by the following statement: "I must have heard the bell ring instead of imagining it merely ; for Robert and Isabel heard it at tlie same time."
6. Give an example from literature (poetry or prose), of imagination which is: (a) visual; (b) auditoi-y; (r) cutaneous; {d) tactual-motor; (e) olfactory; (/) gustatory.
III. 8. Read carefully the following passage: — Next . . . Mowgli . . . was feeling hands on his legs and arms, — strong little hands, which pinched his flesh — and then a swash of
* The Roman numerals refer to the chapters of the book. Questions adapted or quoted from Thorndike's "Elements of Psychology," Titchener's "Primer of Psychology" and Whipple's " Questions in Psychology " are designated by the letters, Th., T., W. In replying to questions which call for examples, students should never repeat those of any text-book of psychology.
Review Questions 401
liranchcs in his face; and then ho was slaring u]) llirough ihc swaying boughs at the fleecy white clouds against the blue sky, as Baloo woke the jungle with his deep cries and tlie birds sang in mockery. . . . Two of the monkeys caught him under the arms and swung off with him through the tree tops . . . The glimpses of the earth far down below frightened him, and the terrible check and jar at the end of the swing over nothing but empty air brought his heart between his teeth.
. . . For a time he was afraid of being dropped ; then he grew angry and then he began to think. The first thing was to send back word to Baloo. — A (1(1 pled from Kipling.
{(j) In the consciousness of Afowgli, thus described, find and name: (i) At least four sensational qualities, of which no two belong to the same class. (2) At least two sensational elements, not qualities, which belong each to a different class. (3) Unsensational elements of at least two sorts.
(/)) Describe, according to the Franklin theory, and according to the Hering theory, the retinal conditions accompanying Mowgli's consciousness of: (1) Tlie blueness of the sky. (2) The whiteness of the clouds.
an orange as you take the orange out of the refrigerator and eat it.
1 1 . .\nalyze into its sensational elements the consciousness involved: (a) in yawning; (b) in lifting your arm from a hanging |)osition to the back of your head.
17. If you were touched (with your eyes shut) on the wrist and on the chest, and then required to re-touch the places struck, you would get more nearly right on the wrist than on the chest. Why?* (r.)
V. ig. Give at least one example of: (a) an instinctive action which becomes habitual; (b) an acquired habitual action; {c) an impulsive movement; {d) a volitional action.
other ways of controlling this instinct. f
VI. 22. Classify each of the following cases of attention: (c) the baby's fixed glance at the bright light; {b) the miser's absorption in contemplating his stock-certificates and bonds; (r) the poet's attention to the composition of a poem ; {d) the schoolboy's attention to it in learning it by heart for to-morrow's lesson; (e) the child's attention to the piece of candy vv^hich he eats; (/) the young girl's attention to the memories of last night's party. {Th.)
26. (a) lA't a friend wlio is unacquainted with the purpose of the experiment, read the passage (.4) on page 385, lines 12-30, of this book. Direct him to "skim it inattentively." Keep a record of the time. Next let him read attentively the passage (B) on page 391, lines 12-31 ; and keep a record of tlie time. Compare the time records in the two cases, {h) Let the subject write what he remembers of each passage. Compare the results. (77/.) (In recording time, use a stop-watch, or a watch with second liand starting at 60. The experiment should be tried with several subjects. With half of them the passages should be read in the order A — B ; with the others, in the order B — A.)
27. Pillsbury, the celebrated chess-player, used, while blindfolded, to play twelve games of chess simultaneously. Is this an instance of simultaneous attention? (7"//.)
28. Do children master the mechanics of reading better by the use of very interesting stories or by the use of relatively uninteresting ones? Why? (W.)
29. Of the 10 interests mentioned below, name (a) four that are largely instinctive, {(>) two that are largely acquired, (r) two that are long delayed, (d) three that appear early in life and also persist. {TJi.) The interest,
VII. 31. Classify, as total or partial (multiple or focalized), and analyze by the use of diagram (cf. pages 107, 109) the association involved in each of the following passages: —
(a) Hilda's {)crception of the "palaces, churches, and imperial sepulchres of Rome with the muddy Tiber eddying through the midst" is followed by the memory of "her native village with its great, old elm trees, the neat, comfortal^le houses scattered along
(r) " What is the feeling of lovers when they recognize a lyre, or a garment, or anything else which the beloved has been in the habit of using? Do not they, from knowing the lyre, form in the mind's eye an image of the youth to whom the lyre belongs?" — Plato.
34. (a) Which part of the total consciousness, "Tuesday, election day, being a holiday, the stores will be closed," would probably be the starting-point of association in the mind of a schoolboy? In the mind of a housekeeper? In the mind of a candidate for office? (b) Compose a similar illustration. (Th.)
36. Suppose stress to be laid on the perfect recitation of a Shakespearian scene, in an elocution class : what would be two differences between the processes of learning it (a) vidth a week before you; (b) with an hour before you?
37. Give an original example of memorizing by grouping facts.
VIII. 38. Describe fully, and compare your experiences, when, as you leave your train, you say : (a) " There is my father. " (6) "That man looks very familiar but I can't remember ever seeing him before."
"Because of tlic annual overflow of the Nile the land in Egypt is fertilized by a deposit of rich soil brought down from the hills to the south. The land thus produces great crops of wheat for the same reason that the river plains of China produce large crops of rice. Hence Egypt used to be called the granary of Rome. The inferior methods of cultivation, largely by hand labor, are due to the lack of inventiveness and of education among the population, who sow by hand." {.Th.)
IX. 42. What kind of experience — perception, imagination, or conception — is normally suggested by each of the following words and phrases: {a) "furniture"; {h) "the desk in the library at home"; {c) " the desk on the platform in front of me"; {d) "benevolence." (If a conception is suggested, classify it.)
45. Of the following expressions, which (if any) are correct? which (if any) are incorrect ? (a) "I am thinking of Weissmann's doctrine of heredity. " {b) " I can't think what the name is. " (r) " I can't think how you could have done it."
X. 47. State three propositions standing respectively for: {a) a particular, negative, analytic judgment; {b) a particular, atlirmative, synthetic judgment; (<) a general, negative, analytic judgment.
induction fcirms one judgment of the deduction.
49. Suppose that you have forgotten whether independence or independance is the correct spelling. How would you 'reason out' the correct spelling from your knowledge of Latin? How would this 'reasoning' differ from 'remembering' how to spell the word?
50. An office clerk sometimes forgot to turn off the electric light when he left at six o'clock and, in this case, he usually returned at eight to extinguish it. The office cat paid no attention to the light till after eight. Then, if the clerk had not returned, she put out the light by pulling down a cord. Describe the consciousness of the cat on tlie supposition that animals do not reason.
55. Give at least two examples each of: (a) exciting, and {b) depressing emotion ; and of (r) emotion with future object, {d) emotion with past object. Where would you place these emotions in the table on pages 175-176?
58. Name, classify, analyze into structural elements, describe as self-related-to-object, the following emotions: {a) the emotion of Shylock toward Antonio; {b) of Macbeth toward Banquo's ghost; (c) of a little boy who is showing a new jack-knife to his schoolmates; {d) the emotions of Mowgli as described in Question 8.
"She felt the slackening frost distil Through her blood the last ooze dull and chill, Her lids were dry and her lips were still."
62. What are the main constituents of your amusement at the following answer to an examination ciuestion: "A vacuum is a chamber of empty air where the Pope lives."
64. What can you say for and against each of the following counsels: (a) " Choose a course in philosophy. It will be good discipline because you don't enjoy the study." {h) "Don't take philosophy. There are plenty of subjects which you like better." (c) "All ready to take the picture. Look bright and animated."
65. Why is, or is not, the following a good method of 'studying' Millet's "Gleaners": "How many women do you see in the picture? How many horses? What else do you see?" (IT., taken from Bagley.)
XH-XHI. 66. Name the differences and ihe likenesses between: (a) willing and wishing; (/;) willing and believing that something will happen ; (r) will and emotion.
67. Analyze into its structural elements, and describe as sclfrelatcd-to-object ; (a) willing to get up in the morning; (/') willing to solve a proI)lcm in gcumctry.
68. Is your present consciousness of yourself as going to the bookstore to buy a book which is "advised" (not "rc(|uired '') in one of your courses (a) an impulse? (/') a simple volition? ((■) a choice ? J ustify your rejection of each of two of these possible answers.
70. Characterize each of the following as illustration of the attitude of will or of faith : (a) Xerxes scourging the Hellespont. ib) The man who exclaimed, "My country, right or wrong!" (r) The Queen of Hearts, in " Alice in Wonderland," who met every crisis with the order '' Off with his head."
INDEX OF SUBJECTS
Abnormal consciousness, 381-309 ; phenomena, 381-3Q2 ; explanation, 392-394 ; veridical phenomena, 39539Q. Bibliography, 399. (Cf. Dreams, Hypnosis, Hallucinations, Illusions).
Esthetic emotion, 42, 176, 190-195 ; definition, 191 ; immersion of self in sense-objects, 191 f. ; attentive, 192 f.; direct and immediate, 193 f. ; disinterestedness of, 194 f. ; excludes organic sensations, 195 ; distinguished from religious consciousness, 268 f. Bibliography, 373.
Affective consciousness, emotion as, 172-175 ; relation to physical stimulus, 374 ; bodily conditions, 374 ; in dreams, 382. Bibliography, 375. (Cf. Emotion).
Affective elements, 128, 172-175, 369-373 ; not always present in consciousness, 173; called "attributive," 174; two, 174; physical stimuli, 197 f. ; physiological condition, 199-204 ; bodily conditions, 200-204. Sensationalist theory of Stumpf, 369. Tridimensional theory of Wundt, 370 ff.
Anim.aus, reasoning of, disproved, 160162, 368; language of, 163 f., 368; •bodily reactions of, 207, 324, 355 ; taste and smell of, 319, 321 ; instincts, 352 f.; learning, 354 f.: bibliography, 356 ; imitation. 355 : bibliography, 356. Bibliography of animal p.sychology, 356.
tions, 401.
Association, 106-115, 359-361 ; simultaneous, 359 ; successive, io6 B. ; total, 107 f., 359 ; partial, 108 fl., 359 ; focalized, 108; "multiple," no; spontaneous, 359 ; controlled, 359 f. ; classification, 112; direction of, 113115 ; effect of interest, frequency, and recencj', 114 f. ; physical condition, 115 ; in memorizing, 120 f. ; in reasoning, 153 ; relation to conception, 139; in mental diagnosis, 361. Bibliography. 359. 361. Review questions, 403 f.
Attention, 93-103, 357 f. ; nature. 93 f objects of, 95-100 ; classes ; natural or instinctive, 100 f. ; acquired, 100 f. physiological conditions, loi f. ; re suits of, 102 f. ; in association, 114 in memorizing, ii8 f. ; relation to judgment, 146; in a;sthetic emotion, 192 f. ; in dreams, 383. Neural conditions, 358. Bibliography, 358. Review questions, 402 f.
AirniTORV consciousness, 16 f!., 41-46; physical condition, 43-45 ; physiological condition, 45 f., 313 ; cerebral center, 296. Beats, 315 f. ; combination tones, 316. Theories, 316 f. : Rutherford, 317 ; Ewald, 317 ; Max Meyer, 317; bibliography, 317 f. Qualities of pitch, 318 f. Localization, 78, 343 ff. Review ([ueslions, 401. (Cf. Harmony, Rhythm, Melofly).
Bodily reactions. Perceptual, 87-02 ; cobrtlinaterl, 88; habitual, 88 I.; immediate, 89 f . ; impulsive, 90 ; nonvolitional, 90 f. ; table of, 91 f. In reasoning, 158-162 ; in emotion, 204207, 370 fi. : in volition, 224 ff., 231 f., 242 ; in faith, 236, 242 ; in dreams, 382 f. ; in hypnosis, 384 f. Instinctive, 351 f. Bibliography, 356. (Cf. Movements) .
Brain, 290-297 ; structure, 290 ff. (Cf. Cerebral hemispheres. Frontal Lobes, Occipital lobes, Parietal lobes, Rolandic area. Temporal lobes).
Color, consciousness of, 29-41 ; elemental, 29 f. ; color square, 30 ; number of color qualities, 31 ; color pyramid, 32 f. ; physical conditions, 34 f. ; physiological conditions, 37 f. Theories of color and colorless light consciousness, 301-308 : Young-Helmholtz, 302, 307 ; Hering, 302-305, 307 ; Franklin, 305-308 ; von Krics, 305 f . BibHography, 308. Contrast phenomena, 308 f. (Cf. Contrast). Purkinje phenomenon, 305 f. Review questions, 401.
physical conditions, 34 f. ; physiological conditions, 37 f. Theories (cf. Color). Review questions, 401.
Combination tones, 316 ; difference tones, 316; summation tones, 316; objective and subjective, 316 ; physiological condition, 316.
Conception, 136-143, 367 ; form of generalization, 141 ; relational consciousness, 136; definition, 136; as experience of generaUty, 136 ; classification : verbal, 137 f., relational, 137 f., motor, 137 f., 367 ; followed by partial associations, 139 ; uses of 140 f. ; dangers of, 141 ; distinguished from imagination, 141 f., 367 ; relation to language, 166. Review questions, 405.
Consciousness, i, 273-280 ; sensational, 14 ; attributive, 14 ; relational, 14 ; immediate and reflective, 284. (Cf. Elements of consciousness, Self).
Contempt, 182, 189.
Contrast, visual, 40, 308 f. Successive, 41: bibhography, 310. Simultaneous, 41, 308 f.: bibliography, 310.
Deliberation, 227 f.
Depth, consciousness of, 72-75, 341 f. ; complex, 73 ; condition of, 74, 342 ; disparate images, 342 ; accommodation, 342 f. ; convergence, 343. (Cf. Space consciousness) .
Distance, consciousness of, 67-70, 335 ; complex, 67 f. Review questions, 402. (Cf. Space consciousness).
Dreams, 381-384 ; analog>' to waking consciousness, 382 ; characterized by hallucination, 382, by unremembered motor reactions, 382 f., by dissociation, 383 f. ; connected with waking consciousness, 383 f. Bibliography, 399-
Elements of consciousness (structural), 14 ff., 29 ff.. 328 ff. ; table of, 331 f. (Cf. Affective elements. Attributive elements. Relational elements. Sensational elements, Extensity, Intensity, Qualities).
Emotion, 170-215, 373 (T. Nature, 170175: as personal attitude, 170-172, 375 ; individual, 170 f. ; receptive, 171 f. ; as affective consciousness, 172-175 ; includes organic sensations, 54, 174 f. Forms, 175-197 : classification, 175 f., 373. Personal, 175-189: egoistic, 177 ff. ; altruistic, 177; sympathetic, 185-189; heterogeneous, 187-189. Impersonal, 189-197: egoistic, 190; altruistic, 190 ff. ; aesthetic, 190-195, enjoyment of logical unity, 196, sense of humor, 196 f., 374. Physical stimuli, 197 f., 374 ; physiological condition, 199-200; bodily conditions, 200-204, 374 f- ; bodily reactions, 204-207. James-Lange theory, 375. Significance of, 208-215 ; control of, 208 f. ; harmful and helpful effects of, 210. Biological significance, 207, 376. Bibliography, 373 ff. Review questions, 406 f.
End-organs, of taste, 50, 319 ff. ; of smell, 319 ff. ; of pressure, 51 f.. 325 ; of pain, 56 f., 326 f. ; of warmth and cold, 59, 326 ; lowest form, 297 ; of animals, 319; in muscles and joints, 327-
E.xtensity, consciousness of, 329, 334 f. ; visual, 34, 69 f. ; physical and physiological conditions, 40 f. ; auditory, 43 ; tactual, 51; in space consciousness, 67 ff., 80 ; empiricist theory, 334 ; nativistic theory, 334 f. Bibliography, 335.
Faith, 233-244. Nature, 233-240 ; adoptive attitude, 233 ; assertive, 233 ; distinguished from belief, 233 f., from will, 234 ff. ; includes feelings of realness and congruence, 234 f., 236239 ; objects of, 233, 235 f. Bodily reactions, 236. Duty of, 238 f. Inner or outer, 2.}o ; deliberative or simple,^ 240. Conflict with will, 240. Signifi- ~^ cance of, 240-244. In religious consciousness, 266 f. Bibliography, 378. Review questions, 408.
Familiar, enjoyment of, 176, 190.
Familiarity, consciousness of, 130 f. ; analysis, 130 ; relational consciousness, 130, 364. Review questions, 404.
Form-consciousness, 70-75 ; two-dimensional, 70-72 ; three-dimensional, 72-75 ; consciousness of position, 7579-
relational experience, 223.
Generality, exiiericnce of, 136 ; includes consciousness of class and consciousness of 'anyness,' 136; in conception, 137 f. (Cf. Conception).
Generalization (cf. Conception), 367 ; based on memory, 117; relation to language. 164 f. Review questions, 405-
Human body, from the psychologist's standpoint, 285-328 ; relation to myself, 285 ; comparison with other objects, 285 ; function, 285 ; motor structure, 286 ; cerebro-spinal nervous system, 286 £f. ; sense organs and the physiological conditions of sensations, 297-328. (Cf. Nervous system, Brain, Cerebral hemispheres, Rolandic area. Ear, Eye, Nose, Skin).
Hypnosis, 355 f., 384-388 ; methods, 384 ; bodily reactions, 384 f. ; hallucinations, 385 f. ; new personality, 386 f. ; connected with waking consciousness, 387 ; post-hypnotic suggestion, 387 f. ; therapeutic use, 388 ; criminal suggestion, 388.
Illusions, 60 f. ; in dreams, 382 ; in hypnosis, 385 ; in waking Ufe, 388 5. ; involuntary, 390. Geometrical, 72, 337341 ; Miiller-Lyer figure, 337 f.; Zbllner figure, 337 f. ; Poggendorf figure, 337 f. ; Schroder figure, 338 f. ; explanations, 338 f.
Imagination, n-28, 61 ; as unshared experience, 12; as impersonal, 13; as particularizing consciousness, 13 ; as sensational experience, 14 ff. ; concrete, 16-23 ; visual, 16 £[. ; auditory, 16 f., 21 ; tactual, 16 f., 20 f. ; of smell and taste, 22 f. ; mixed, 23 ; verbal, 23 ff. ; sensational elements of, 29-62 ; physiological condition, 60 ; as fusion and assimilation, 63-66 ; as realized combination and differentiation, 66-85 ; as combination of limited groups of sense-elements, 85 f. ;
bodily reactions in, 87-92 ; productive and reproductive (cf. Memoo')> 104-106, 1x5-123; association, 106115; in . recognition, 125 f. ; distinguished from thought, 133 f. ; distinguished from conception, 141 f., 367 ; relation to judgment, 144 f. Bibliography, 284. Review questions, 400.
Imitation, 252-259 ; fashion and tradition, 254 ; physical and psychic, 255 ; personal, 255 f. ; related to opposition, 257 f. Of animals, 355. In hypnotism, 355 f. Bibliography, 378.
Intensity, consciousness of, 329 f. ; visual, ss f- ; physical and physiological conditions, 40 f. ; auditory, 42 f. ; taste, 50; tactual, 51. (Cf. Brightness, Loudness) .
Joy, bodily conditions, 203 f.
Judgment, 144-158; definition, 144; as experience shared with other selves, 144 ; complex, 144 ; relational experience, 144 ; objects of, 144 ; distinguished from perception, 144 f. ; classification : particular or general, 14s f. ; positive or negative, 146, 147 ; analytic or synthetic, 146 f. ; reasoning, 148-162. Bibliography, 368. Review cjuestions, 405. (Cf. Reasoning).
Language, nature and origin, 368 ; related to conception, 141 ; related to thought, 162-169, 368; definition, 163; natural, 163; conventional, 163 ff. ; of animals, 163 f., 368; accjuired by imitation, 254.
Learning, .Vv5-,3S6 ; physical and psychical, 35,5 f. ; presupposes piemory, 354 ; individual and social, 354. Of animals, 354 f.
Localization, 75-79, 335 f. ; two-dimensional, 75 f. ; three-dimensional, 75 ff. Visual, 77 f. Auditor>', 78 f., 343 ff. ; facts, 343 f. ; physical condition, 344 f. ; phjsiological condition, 345 ; nativistic theory, 346 ; empiricist or motor theory, 346 ff. Bibliography, 349. Review questions, 402.
raphy, 349.
Memory, reproductive imagination, 106, 115-123; essential to learning, 117, 354 ; methods of memorizing, 11 7-1 23 ; by attention, 118 f., grouping, 119 f., association, 120 f., repetition, 121 f. Loss of, in hypnosis, 386 f. Bibliography, 361. Revdew questions, 404. (Cf. Recognition).
Movements, bodily, voluntar>', 226, 231 f. ; impulsive, 226, 231 f. ; imitative, 252 ff. ; characteristic of cerebral activity, 202, 296 ; con-
Nose, structure of, 320.
Objects, of the self, 3 ff., 280-282 ; personal and imi)ersonal, 3 f., 281, 369 ; private and public, 3 f., 281 ; externalized and non-externalized, 4, 281 ; table of, 4 ; myself as object, 3 f., 280 f. ; human body as object, 285. Of perception, 12 f.; of imagination, 12; of attention, 95-100; of recognition, 127; of thought, 133 f. ; of emotion, 175 ff., 369; of will, 219 f. ; of faith, 233 ff.; of belief, 233 ff.
Pain, consciousness of, 55-57 ; physical condition, 56 ; physiological condition (end-organs), 56 f., 326 f. ; factor in taste consciousness, 49.
Past, consciou.sness of, 130 f., 21 p.
Perception, ii ff., oi, 284 ; passive, 12 ; as experience shared with other selves, J?.; implies oliject independent of self, 12 f. ; as impersonal, 13; as particularizing consciousness, 13 ; as sens;itional experience, 14 ff., 172;
sensational elemi-nts of. 20-62 ; physiological comlilion, 00 ; as fusion and assimiliation, (),i -(>(); as ri-alized combination and ditlcrentiation, 60-85 (cf. Space, Rhythm) ; as combination of limited groups of sense-elements, 8s f. ; bodily reactions in, 87-92 ; distinguished from thought, 133 f. ; relation to judgment, 144 f. Bibliography, 284. Review questions, 400. (Cf. Attention).
Present, the, 219.
Pressltre, consciousness of, So-54 ; physical condition, 51 f. ; physiological condition (end-organs), 52, 325 ff., 335 ; cerebral condition, 54 ; factor in taste consciousness, 49.
Psychoanalysis, 361.
Psychology, nature, i ff. ; methods, 6 fl. ; as science of the self, 1,5, 273282 ; experimental, 7 f. ; comparative, 354 ; normal and abnormal, 8 f., 381-399 ; use of, 9 f. ; in novel and in drama, 261 f. ; as science of ideas, 273 f., 278 f. ; as science of mental functions, 274 f., 277. Bibliography on fundamental conceptions of, 282 f.
Purkinje phenomenon, 305 f.
Qualities, 329; sensational, 29 ff., 198. Review questions, 401. (Cf. Sensational elements. Color, Colorless light. Noise, Pitch, Taste, Smell, Pressure, Pain, Temperature consciousness).
Re.\soning, 148-162; definition, 148; deductive, 148 f. ; inductive, 148 ff. ; analytic-synthetic, 152 f. ; uses of, 153-156; dangers of, 156-158; bodily reactions, 158-162; of animals, 160162, 36S ; without words, 168. Bibliography, 368. Review questions, 405 f-
Recognition, 124-132 ; distinguished from memory, 124; supplemented by associated imagination, 125 f. ; includes consciousness of persisting self, 126 f., 131; object of, 127; as relational consciousness, 127-131 ; experimental study of, 362.
Reflex reaction, 90.
Relational consciousness, 14, 66, 127-131, 223; in dreams, 382. Review questions, 404 f. (Cf. Recognition, Thought).
Relational elements, 127-131, 330 f., 362-366; opposing theories, 127 f., 130 ; favoring theories, 362 f. ; found in experience, 12S; confirmed by experiments, 363 f. ; enumeration, 128 f., j3S'y physiological condition, 128 f. ; in consciousness of generality, 136 f. Bibliography, 365 f.
Relief, 174.
Religious consciousness, 262-270, 379 f. ; definition, 262 f. ; historical forms, 263 ; rites, 264 f. ; personal, 265 ; active, 266 f. ; distinguished from moral consciousness, 267 f., from ffisthetic consciousness, 268 f., from conviction of reality, 269.
Self, persistent, :•,, 14; complex. 3, 14; unique, 3, 14: related, .s. 1 1- .\s efjoistic, 17s ff., 21O IT.; as altruistie, 175 ff., 232 ff. ; as particularizing and individualizing, 13, 170 flf., 218 IT.. 234 ff. ; as generaliziuK, 136 ff. ; as receptive or passive, 11 ff., 171 ff. ; as active or assertive, 210 ff., 232 ff. As perceiving and imagining, 11 ff. ; as recognizing, 124 ff. : as thinking, 133 ff. ; as emotional. 170 ff. ; as willing, 216 ff. ; as believing, 231 ff. ; as social, 245 ff. ; as religious, 260 ff. As object, 3 f., 280 f. ; as subject, 4 f. Secondary or subconscious self, 392 ff. (Cf. Consciousness) .
Sensation, 60.
Sensational consciousness, object of, 8s ; in dreams, 382. Review questions, 401. (Cf. Auditory consciousness. Cutaneous consciousness. Gustatory consciousness, Olfactory consciousness. Visual consciousness).
Sensational elements, 14 ff., 128, 328 ff. ; of perception and imagination, 29-62 ; combined with intensity and extensity, 59. Review questions, 401.
Smell, consciousness of, 47 ; factor in taste consciousness, 49 ; cerebral centre of, 296, 321 ; end-organs of, 319 ff. ; of animals, 321. Bibliography, 323.
Social consciousness, 245-2S9 ; mob consciousness, 245-248 ; imitative, 245 f. ; capricious, 246 ; reflective, 249 ff. ; dominating, 240 f. ; moral consciousness, 251 f. : imitation, 252-259; opposition, 256-259. Bibliography, 378. (Cf. Self).
Somnambulism, 383.
Space consciousness, 66-81, 334 ff. ; elements of, 66 f. ; consciousness of distance, 67-70, 335 ; consciousness of form, 70-75 ; consciousness of position, 75-79 ; empiricist theory, 80. (Cf. Extensity, Illusions, Localization).
Taste, consciousness of, 47-50 ; complexity, 49 ; qualities, 50 ; physical and physiological conditions, 50, 321 ; cerebral centre, 296, 323 ; end-organs, 319 ff. Bibliography, 323.
Temperaturi; consciousness, 57-59 ; physical condition, 58 ; physiological condition, 58 f. Bibliography, 328.
Thought, 133-169, 367 ; distinguished from perception and imagination, 133 f. ; relational experience, 133 f., 135 ; impersonal, 134 ; as experience shared with other selves, 134 f., 367 ; causal thinking, 135 ; comparison, 135 ; conception, 136-143 ; judgment, 144147 ; reasoning, 148-162 ; bodily reactions, 158-162 ; relation to language, 162-169, 368; often result of volition, 216 note. (Cf. Conception, Judgment, Reasoning).
Vanity, 176, 183 f.
Veridical phenomena, 305-399 ; telepathy, 395 f. ; clairvoyant visions, 396 f. ; mediumistic revelations, 396 ff. ; theories, 398 f.
Visual consciousness, 16 ff., 28-41, 301 ff. ; physical conditions, 34 f. physiological conditions, 37 f., 297 ff. factor in taste consciousness, 49 cerebral centre of, 295 f. ; local sign 336. (Cf. Color, Colorless Light).
Voi.iTio.v, 216-232, 377 ; anticipatory, 221 ff. ; classification, 223 f. ; outer volition, 224 ff. ; inner volition, 226 f. ; simple volition, 227 ff. ; choice, 227 ff. ; without effort, 228 f. ; with effort, 228 f. (Cf. Will).
Wholeness, experience of, 144 f.
Will, 216-232, 376. Nature, 216-223 •' as personal attitude, 216-220; active, 216 ; imperious, 216 f. ; individualizing, 218; with and without temporal reference, 218; objects of, 2 1 9 f . ; as anticipatory consciousness, 220-223. Forms, 223-230 (cf. Volition) ; bodily conditions, 231 f . ; distinguished from faith, 234 ff. ; conflict with faith, 240 ; significance of 240-244. Review questions, 407 f.
"To expound the metaphysics of modern Europe is no light task, but Professor Calkins has accomplished it for the most part in a clear and scholarly manner, licginners may read her ' Introduction' with understanding; and even those who are weary with the confusion of metaphysical tongues will be interested in the freshness of her comment and criticism. The chapters on Descartes and Leibnitz are good e.\am])les of the way in which the history of philosophy should be written and the criticism of philosophy performed. . . . The exposition of Fichte is undertaken in such sympathy with that philosopher, that it is almost dramatic. No author writmg in English has surpassed Professor Calkins in giving a clear and simple interpretation of Hegel, free from the uncouth language which disfigures most Hegelian commentaries.
" Professor Calkins not only criticises, but constructs, and sets forth her own doctrine with such ability that she should have a distinguished place among contemporary Hegelians." — From 77ie Nation, New York.
"The historical and critical portions of the volume are written with a facile pen. Few recent treatises on philosophy have combined so constant reference to the sources with so readable an expository style. The writer exhibits a comprehensive acquaintance with the history of modern thinking, at the same time that she exercises independent historical judgment. . . . Unstinted commendation must be given to the spirit of Miss Calkins's work. Never has there been a fairer attempt to solve the difficult problem of evolving doctrine from historical analysis." — Professor A. C. Armstrong, in The Journal of Philosophy.
" It is exceptional in lucidity, candor, and the freshness with which it surveys well-worn doctrines. More than any Introduction to Philosophy with which I am acquainted, it will induce its reader to turn to the original sources, and to find pleasure in seeing Philosophy as it rises in the minds of the great thinkers. While the book is unusually attractive in style, and well fitted for popular use, it is the work of an original and critical scholar. The temper with which the history of philosophy should be studied finds here admirable expression." — Professor George H. Palmer, Department of Philosophy, Harvard University.
"The reader of this book is impressed, first of all, by the wide range of topics discussed. Most of the text-books on psychology do not attempt to cover more than one phase of the subject. If they treat of the normal consciousness of the developed adult, they do not attempt to do more than refer to the phenomena of abnormal mental life, or to the facts of undeveloped child life, or to the still more remote facts of animal consciousness. Miss Calkins, on the other hand, has given to all of these subjects a sufficient degree of attention to justify the statement that the book is a general text-book, covering all departments of this now complex science of psychology.
" In the second place, the reader will find in this book a very great deal of attention given to what may be called the social phases of mental life. It is not merely the analysis of one's own mental experiences, nor merely the explanation of one's own ideas that we find here undertaken ; there is also a full discussion of the ' relations between selves,' or, to put it in other terms, of the facts and results of social interaction, and social consciousness." — Professor Charles H. Judd, in the Journal of Pedagogy.
" A satisfactory college text-book . . . calls for lucidity of treatment, . . . accuracy of statement, and readableness. In these regards the present book is one of high merit. . . . Those readers whose study is not assisted by explanatory lectures will appreciate the rare skill with which the author has translated abstract terms and concepts into concrete images and brought the formal discussion of mental functions into touch at every point with the literary expression of experience." — Professor Robert Macdougall, in IVie Psychological Review.
" Miss Calkins is an excellent guide to follow. Her arrangement of her material is admirable, her summaries come in just at the right places. . . . The whole field ... is surveyed in a masterly way ; comparative and abnormal psychology is treated briefly but with much judgment ; a history of psychological doctrines is added." — From The Scotsman, Edinburgh.
This is intended as a first book, compreliensive enough to give the general reader a tair idea ot the field of modern psychology, its methotis of research, and an outline of its most important results. Every statement is made with as little of technical detail as is practicable. It is sutticient to meet the needs of the ordinary reader who wishes to understand something of the subject so prominent in all discussions of education and business lite ; the student who proposes to make a special study of psychology will find it time well spent it he reads this book first. Cloth, i2ino, ji6 pages, $/.oo net
The Psychology of Feeling and Attention
A Course of Lectures, delivered by invitation at Columbia University, which bring together all we at present know of the elementary affective processes and of the attentive state. The entire discussion constitutes a sort of critical re'sume of experimental work up to 1908.
A much enlarged and revised edition taking the place of the well-known work, "An Outline of Psychology," first issued in 1896, frequently reprinted, also translated into Russian and Italian. Part I. Cloth, i2mo, $/.jo ntt
By OSWALD KilLPE,
A Handbook for Students of Psychology, Logic, Ethics, ^Esthetics, and General Philosophy. Translated by Professors W. B. Pillsbury and E. B. TITCHENER. ^^^^^^ ^^^ ^^^^^^ ^^^_ ^^_^^
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iaWzTqZu231n37Of | Morris's human anatomy; a complete systematic treatise by English and American authors, ed. by C.M. Jackson eleven hundred and eighty two illustrations, three hundred and fifty eight printed in colors. | AREANGEMENT OF SUBJECTS AND AUTHORS
The names of the more recent of those who wrote or revised articles for previous editions have been retained in the following list in order that due credit should be given them for the work done and for their share in the great success which Morris's "Anatomy" has achieved.
MORPHOGENESIS. Revised and largely rewritten for the fifth edition by
C. M. Jackson, M.S., M.D., Professor of Anatomy in the University of Minnesota. Originally written by J. Playfair McMurrich, A.M., Ph.D., Professor of Anatomy, University of Toronto.
OSTEOLOGY. Revised for the third, fourth and fifth editions by Peter Thompson, M.D., Professor of Anatomy, University of Birmingham; Member of Anatomical Society of Great Britain. This article was originally written by Sir John Bland Sutton, F.R.C.S.
ARTICULATIONS. Revised for the fifth edition by Frederic Wood Jones, D.Sc, M.B., B.S. (Lond.), M.R.C.S., L.R.C.P., Head of the Department of Anatomy and Lecturer in the London School of Medicine for Women. Originally written by Su- Henry Morris, A.M., M.B.
MUSCLES. Rewritten and revised for the fourth and fifth editions by Charles R. Bardeen, A.B., M.D., Professor of Anatomy in the University of Wisconsin; Member Association of American Anatomists; Member of Editorial Board of "American Journal of Anatomy."
D. Senior, M.B., F.R.C.S., Professor of Anatomy, University and Bellevue Hospital Medical College. The section on Blood-vessels was formerly revised by Florence R. Sabin, B.S., M.D., Associate Professor of Anatomy, Johns Hopkins University.
LYMPHATIC SYSTEM. Revised and partly rewritten for the fifth edition by Eliot R. Clark, A.B., M.D., Associate in Anatomy, Johns Hopkins University. Revised for previous edition by Florence R. Sabin, B.S., M.D.
NERVOUS SYSTEM. Revised and largely rewritten for the fourth and fifth editions by Irving Hardesty, A.B., Ph.D., Professor of Anatomy, Tulane University, Louisiana; Member Association of American Anatomists.
SPECIAL SENSE ORGANS. Revised for the fifth edition by David Waterston, M.A., M.D., F.R.C.S., Professor of Anatomy in the University of London. In the earlier edition, the Ear, Nose, Tongue were revised by Abram T. Kerr, B.S., M.D.
DIGESTIVE SYSTEM. Revised and largely rewritten for the fifth edition by C. M. Jackson, M.S., M.D., Professor of Anatomy, LTniversity of Minnesota. Revised for the fourth edition by G. Carl Huber, M.D.
RESPIRATORY SYSTEM. Revised for the fourth and fifth editions by R. J. Terry, A.B., M.D., Professor of Anatomy, Washington University, St. Louis; Member Association of American Anatomists.
UROGENITAL SYSTEM. Revised for the fourth and fifth editions by J. Playfair McMurrich, A.M., Ph.D., Professor of Anatomy, University of Toronto; Member Association of American Anatomists.
By Abram T. Kerr, B.S., M.D., Professor of Anatomy, Cornell University; Member Association of American Anatomists, etc. The article on the Ductless Glands was originally written by G. Carl Huber, M.D.
CLINICAL AND TOPOGRAPHICAL ANATOMY. By John Morley, Ch.M., F.R.C.S., Honorary Surgeon, Ancoats Hospital, Manchester, and Lecturer in Clinical Anatomy, Manchester University. Originally written by W. H. A. Jacobson, F.R.C.S.
One criticism upon most of the current text-books of human anatomy is that they are too extensive for the beginner. Much precious time is wasted by him in floundering through a mass of details which obscure the fundamental facts. And yet it is important to have these details conveniently accessible for both present and future reference. To meet this difficulty, the attempt is made in this edition to discriminate systematically in the use of sizes of type. The larger type is used for the more fundamental facts, which should be mastered first, and the smaller type for details. While it has been found difficult to apply this principle uniformly through the various sections, it is hoped that the plan, even though but imperfectly realized, will prove useful to the beginner.
by dotted black lines.
While the authors of the present edition are for the most part the same as in the previous edition, a few changes have been made as noted under the preceding section, "Arrangement of Subjects and Authors." Owing to the retirement of the distinguished originator and former editor of this work. Sir Henry Morris, and of Professor McMurrich as co-editor, the responsibility for the general supervision of the fifth revision has fallen to the present editor.
Each author is alone responsible for the subject-matter of the article following his name. Care has been exercised on the part of the editor, however, to make the whole uniform, complete and systematic.
As to nomenclature, the Anglicised form of the BNA has been continued, excepting those cases where the Latin form is adopted into English (e. g., most of the muscles), and rare cases where the BNA term seems undesirable. As a rule, the Anglicised form where first used is followed by the BNA Latin term in brackets, except where the two are practically identical. For convenience of reference, some of the commoner synonyms of the old nomenclature are also added in parenthesis.
The previous edition of Morris's Anatomy was the first general text-book of anatomy in English to adopt the BNA. During the past few years the merit of this system of nomenclature has become so widely recognized that it is now very generally accepted among the English-speaking nations. Lack of space forbids the enumeration here of the many advantages of this system, not the least of which is the reduction of some 30,000 anatomical terms (including synonyms) to 5000. The comparatively few defects of the BNA will doubtless be remedied by revision (preferably through the International Anatomical Congress). For a full discussion of the BNA system, with complete Hst of the Latin terms and English equivalents, the reader is referred to the excellent work on the BNA by Professor L. F. Barker, of Johns Hopkins University.
In addition to the bibliographical references scattered throughout the text, a brief list is given at the close of each section. These brief lists of carefully selected references are intended merely as a guide to put the student "on track" of the original literature.
In addition to a thorough revision of the various sections, there has also been a rearrangement of a part of the subject matter in the present edition. The Teeth have been transferred from the section on Osteology to the Digestive System. The Tongue and Nose are transferred to the Digestive System and Respiratory System, respectively, excepting those portions forming the organs of Taste and Smell, which have been retained in the section on Special Sense Organs. The Pelvic Outlet has been discontinued as a separate section, the subject matter being divided between Musculature and Clinical and Topographical Anatomy. The Ductless Glands have been included in the section with the Skin and Mammary Glands.
Due credit has been given throughout the book wherever illustrations have been taken, or modified, from other works. Special acknowledgment should be made of our indebtedness to the works of Toldt, Rauber-Kopsch, Poirier and Charpy, Henle and Spalteholz.
The number of figures in the present edition has been increased about one hundred and sixty and in addition many of the older figures have been improved or replaced. For the generosity of the publishers in this connection, and for the hearty cooperation of the contributors in the revision of the various sections, the editor desires to express his deep indebtedness. Valuable assistance has been rendered by Mr. Walter E. Camp in the reading of proof and preparation of the index.
PROFESSOR OP ANATOMY, TJNrVEHSITT OP MINNESOTA.
ANATOMY, as the term is usually employed, denotes the study of the /-\ structure of the human body. Properly, however, it has a much wider -^-*- significance, including within its scope not man alone, but all animal forms, and, indeed, plant forms as well; so that, when its application is limited to man, it should be qualified by the adjective human. Human Anatomy, then, is the study of the structure of the human body, and stands in contrast to, or rather in correlation with. Human Physiology, which treats of the functions of the human body, the two sciences, Anatomy and Physiology, including the complete study of man's organization and functional activities.
In the early history of the sciences these terms sufficed for all practical needs, but as knowledge grew, specialization of necessity resulted and new terms were from time to time introduced to designate special lines of anatomical inquiry. With the improvement of the microscope a new field of anatomy was opened up and the science of Histology came into existence, assuming control over that portion of Anatomy which dealt with the minuter details of structure. So, too, the study of the development of the various organs gradually assumed the dignity of a more or less independent study known as Embryology, and the study of the structural changes due to disease was included in the science of Pathology; so that the term Anatomy is sometimes limited to the study of the macroscopic structure of normal adult organisms.
It is clear, however, that the lines of separation between Anatomy, Histology, Embryology, and Pathology are entirely arbitrary. Microscopic anatomy necessarily grades ofi' into macroscopic anatomy; the development of an organism is a progressive process and the later embryonic or foetal stages shade gradually into the adult; and structural anomalies lead insensibly from the normal to the pathological domains. Furthermore it is found that in its individual development the organism passes through stages corresponding to those of its ancestry in evolution; in other words, Ontogeny repeats Phylogeny. A comprehensive study of Anatomy must therefore include more or less of the other sciences, and since an appreciation of the significance of structural details can only be obtained by combining the studies of Anatomy, including Histology and Embryology, and since, further, much light may be thrown on the significance of embryological stages by comparative studies, Anatomy, Embryology, and Comparative Anatomy form a triumvirate of sciences by which the structure of an organism, the significance of that structure, and the laws which determine it are elucidated. For this combination it is convenient to have a single term, and that which is used is Morphology, a word meaning literally the science of form.
In morphological comparisons, the term liomology denotes similarity of structure, due to a common origin in the evolution of organs or parts; while analogy denotes merely physiological correspondence in function. Thus the arm of man and the wing of a bird are homologous, but not analogous, structures; on the other hand, the wing of a bird and the wing of an insect are analgous, but not homologous. Serial homology refers to oorresp ending parts in successive segments of the body.
Nomenclature. — Formerly there was much confusion in the anatomical nomenclature, due to the multiphcity of names and the lack of uniformity in using them. Various names were applied to the same organs and great diversity of usage prevailed, not only between various countries, but also even among authors of the same country. Recently, however, a great improvement has been made by the general adoption of an international sj^stem of anatomical nomen-
2 INTRODUCTION
clature. This system was first adopted by the German Anatomical Society at a meeting in Basel, in 1895, and is hence called the Basel Nomina Anatomica, or briefly, the BNA. The BNA provides each term in Latin form, which is especially desirable for international usage. Each nation, however, is expected to translate the terms into its own language, wherever it is deemed preferable for everyday usage. Thus in the present work the Anglicised form of the BNA is generally used. Where not identical, however, the Latin form is added once for each term in a place convenient for reference, and is designated by enclosure in brackets [ ]. Where necessary the older terms have also been added as synonyms.
The Commission by whom the BNA was prepared included eminent anatomists representing various European nations. The work of the Commission was very thorough and careful, and extended through a period of six years. Among the guiding principles in the difficult task of selecting the most suitable terms were the following: (1) Each part should have one name only. (2) The names should be as short and simple as possible. (3) Related structures should have similar names. (4) Adjectives should be in opposing pairs. A few exceptions were found necessary, however.
On account of its obvious merits, the BNA system has been generally adopted throughout the civilised world, and the results are very satisfactory. Comparatively few new terms have been thereby introduced, over 4000 of the 4500 names in the BNA corresponding almost exactly to older terms already in use by the Enghsh-speaking nations. Certain minor defects in the system have been criticised; but these are outweighed by the advantages of this uniform system.
Abbreviations. — Certain frequently used words in the BNA are abbreviated as follows: a., arteria (plural, aa., arterise); b., bursa; g., ganglion; gl., glandula; lig., ligamentum (plural, ligg., ligamenta); m., musculus (plural, mm., muscuU); n., nervus (plural, nn., nervi); oss., ossis (or ossium); proc, processus; r., ramus (plural, rr., rami); v., vena (plural, vv., venae).
Terms of position and direction. — The exact meaning of certain fundamental terms used in anatomical description must be clearly understood and kept in mind. In defining these terms, it is supposed that the human body is in an upright position, with arms at the sides and palms to the front.
The three fundamental planes of the body are the sagittal, the transverse and the frontal. The vertical plane through the longitudinal axis of the trunk, dividing the body into right and left halves, is the median or mid-sagittal plane; and any plane parallel to this is a sagittal plane. Any vertical plane at right angles to a sagittal plane, and dividing the body into front and rear portions is a frontal (or coronal) plane. A plane across the body at right angles to sagittal and coronal planes is a transverse or horizontal plane.
or caudal.
The term medial means nearer the mid-sagittal plane, and lateral, further from that plane. These terms should be carefully distinguished from internal (inner) and external (outer), which were formerly synonymous with them. Internal, as now used (BNA), means deeper, i. e., nearer the central axis of the body or part; while external refers to structures more superficial in position. Proximal, in describing a limb, refers to position nearer the trunk; while distal refers to a more peripheral position.
It should also be noted that the terms ventral, dorsal, cranial and caudal are independent of the body posture, and therefore apply equally weU to corresponding surfaces of vertebrates in general with horizontal body axis. On this account these terms are preferable, and wiU doubtless ultimately supplant the terms anterior, posterior, superior and inferior.
The discrimination in the use of several similar terms of the BNA should also receive attention. Thus medianus (median) refers to the median plane. Medialis (medial) means nearer the median plane and is opposed to lateral, as above stated. Medius (middle) is used to designate a position between anterior and posterior, or between internal and external. Between medialis and lateralis, however, the term intermedius is used. Finally, transversalis means transverse to the body axis; transversus, transverse to an organ or part; and iransversarius, pertaining to some other structure which is transverse.
Parts of the body. — The primary divisions of the human body (fig. 1) are the head, neck, trunk and extremities. The head [caput] includes cranium and face [facies]. The neck [coUum] connects head and trunk. The trunk [truncus] includes thorax, abdomen, and pelvis. The upper extremity [extremitas superior] includes arm [brachium], forearm [antibrachium], and hand [man us]. The
Each of the parts mentioned has further subdivisions, as indicated in fig. 1. The cranium includes : crown [vertex] ; hack of the head [occiput] ; frontal region [sinciput], including forehead [frons]; temples [tempora]; ears [aures], including auricles [auriculfe].
the subdivisions of which will be given later under the appropriate sections.
The thorax includes: hreast [pectus]; mammary gland [mamma]; and thoracic cavity [cavum thoracis]. The hack [dorsum] includes the vertebral column [columna vertebralis]. The abdomen includes: navel [umbilicus] ; ^awfc [latus]; groin [inguen]; loin [lumbus]; and the abdominal cavity [cavum abdominis]. The hip [coxa] connects the pelvis with the lower extremity.
In the lower extremity, the thigh is joined to the leg by the knee [genu]. The foot includes: heel [calx]; sole [planta]; instep [tarsus]; metatarsus; and five toes [digiti I-V], including the great toe [hallux] and little toe [digitus minimus].
syndesmology for arthrology); of the vessels, angiology; of the muscles, myology; of the nervous system, neurology; and of the viscera, splanchnology. Further subdivisions are also made. The viscera, for example, include the digestive tract, respiratory tract, urogenital tract, etc.
Tissues and cells. — The body, as above stated, has various parts, each of which may be subdivided into its component systems and organs. A further analysis reveals a continued series of structm'al units of gradually decreasing complexity. Thus each organ is found to consist of a number of tissues (epithehal, connective, muscular or nervous). Finally, each tissue is composed of a group of similar units called cells (figs. 2, 3) which are the ultimate structural units
of the body. The body may therefore be regarded as composed of myriads of cell units, organized into units of gradually increasing complexity, very much as a social community is composed of individuals organized into trades, municipalities, etc.
Most of the individual tissues can be recognized by their gross appearance. In fact, the principal tissues were first demonstrated by Bichat through skilful dissection, maceration, etc., and without the aid of the microscope. The cellular structure of the tissues was later discovered by Schwann in 1839.
Each cell (fig. 3) is composed of a material called ■protoplasm, a viscid substance variable in appearance and exceedingly complex in chemical composition. It readily breaks down into simpler chemical compounds, whereby energy (chiefly in the form of heat and mechanical energy) is liberated. It has also the power of absorbing nutritive material to build up and replace what was lost. Its decomposition results from stimuli of various kinds, and hence it is said to be irritable. The mechanical energy which it liberates is manifested by its contractihty, especially in the muscle cells. It excretes the waste products produced by its decomposition. Each cell has the power, under favourable conditions, of reproducing itself by division. Protoplasm presents, in short, all the forms of activity manifested by the body as a whole; and, indeed, the activities of the body are the sum of the activities of its constituent cells.
In the protoplasm of each cell is a specially differentiated portion, the nucleus (fig. 3). The nucleus plays an important part in regulating the activities of the cytoplasm, the general protoplasm of the cell body. The nucleus differs from the cytoplasm both structurally and chemically, and contains a very important substance, chromat^in, which during cell division is aggregated into a definite number of masses called chromosomes. The cytoplasm of actively growing cells also contains the archoplasm and centrosome, structures of importance in the process of cell division. Further details concerning the cells and tissues may be found in the text-books of cytology and histology.
In earher days Human Anatomy was almost entirely a descriptive science, but little attention being paid to the significance of structure, except in so far as it could be correlated with physiological phenomena as they were at the time understood. In recent years attention has been largely paid to the morphology of the human body and much valuable information as to the meaning of the structure and relations of the various organs has resulted. Since the form and structure of the body are the final result of a series of complicated developmental changes, the science of Embryology has greatly contributed to our present knowledge of human Morphology; and, accordingly, a brief sketch of some of the more important phases of morphogenesis will form a fitting introduction to the study of the adult.
References. — General: For looking up the literature upon any anatomical topic, the best guide is the " Jahresbericht ueber die Fortschritte der Anatomie und Entwicldungsgeschichte," which contains classified titles and brief abstracts of the more important papers in gross anatomy, histology and embryology. Other useful aids are the "Zentralblatt fuer normale Anatomie," the "Index Medicus" and the catalogue of the Surgeon Genera 's Library of the War Dep't. (Washington, D. C). The latter two contain titles only, but cover the whole field of medicine. The "Concilium Bibliographicum" also provides a convenient card-index system of references for the biological sciences, including Anatomy.
For nomenclature: His, Archiv f. Anat., 1895 (BNA system); Barker, Anatomical Nomenclature. Cells and tissues: Wilson, The Cell; Hertwig, Zelle und Gewebe (also English transl.) ; Sehaefer, Microscopic Anatomy (in Quain's Anatomy, 11th ed.) ; Heidenhain, Plasma und Zelle.
PROFESSOR OF ANATOMY IN THE tJNIVERaiTY OF MIN
CHANGE is a fundamental characteristic of all living things. The human body during its life cycle accordingly passes through various phases of form and structure. In the earliest embryonic phases of development the changes are very rapid, decreasing in rapidity during the later foetal stages, but continuing at a diminishing rate throughout infancy, childhood and youth up to the adult. Following the acme of maturity, changes continue which lead gradually to senescence and final death of the body.
This cycle of change in the body depends upon similar changes in its various component organs, each having its own characteristic hfe cycle. In a few of the organs this cycle is very short, as in some of the organs of the embryo (e. g., mesonephros). Other organs persist only during childhood (e. g., thymus); while the majority continue, with varying degrees of change, throughout postnatal life. The final death of the body is due to the breakdown of some of the essential organs.
A further analysis reveals the fact that the characteristic life cycles of the organs depend ultimately upon similar changes in their constituent tissues and cells. Every ceU has a definite life cycle, an early period characterised by rapid and vigourous changes, later periods of differentiation and maturity, followed by stages of degeneration and death. This cycle of cell changes has been designated by Minot as cytomorphosis.
Growth. — Associated with the process of cell differentiation (cytomorphosis), and even more important as a factor in the morphogenesis of the body, is the process of growth. The developmental changes in form and structure of the body are due largely to the unequal growth of its various parts. Growth, like other changes in the body and its parts, depends ultimately upon the characteristics of the constituent cells.
Nucleus
The cell changes during growth may be grouped under two heads. The first, or growth proper, involves merely the enlargement (hypertrophy) of the individual cells and intercellular products. The second includes the muUiplication (hyperplasia) of the cells, which is accomplished by mitotic division. Cell division is necessary in ceU growth, for otherwise the cell would soon reach a size where its surface (for nutritive, respiratory and excretory purposes) would be inadequate for its mass. In general, however, cell division is most active in the earher embryonic periods, during which the cells remain small. Later, cell division diminishes or ceases, and growth is due chiefly to enlargement of the cells already present. It is also during the later period, when the cells have ceased rapid division, that the process of cell differentiation and tissue formation is most marked.
The principle of the ratio of surface to mass often apphes to the growing organs as well as to the individual cells. To maintain the necessary ratio, the surface area is increased by the formation, through localised unequal growth, of projections (e. g., villi or folds) or invaginations (e. g., glands) from surfaces. Innumerable modifications of this principle occur throughout the process of morphogenesis.
8 MORPHOGENESIS
Fig. 5. — Ovum fkom Ovaey of a Woman Thibtt Years of Age. cr, corona radiata. n, nucleus, y, yolk, p, clear protoplasmic zone, ps, perivitelline space, zp, zona pellucida. (McMurrich's Embryology, from Nagel.)
SEGMENTATION OF THE OVUM
While the present work deals primarily with the adult human organism in the stage of maturity, reference is made also to its changes according to age. Although these changes for the various systems of organs are described under the appropriate sections, it is desirable to consider first some of the more fundamental features pertaining to the body as a whole. This apphes particularly to the earlier embryonic period, which includes the more general phases of morphogenesis. No attempt will be made to describe fully the process of development, the details of which are to be found in text-books of embryology.
Segmentation of the ovum. — The human body, like all living organisms, arises from a single cell, the egg-cell or ovum. An early stage in the development of the ovum is shown in fig. 4, and a later stage, approaching maturity, in fig. 5. The mature human ovum is about 0.2 mm. in diameter. In the uterine (Tallopian) tube, the fertilised ovum undergoes segmentation, the various stages of which are represented in figs. 6 and 7.
While the processes of maturation, fertilisation and segmentation have not as yet been observed in the human ovum, the evidence of comparative anatomy makes it very prolDable that in all essential respects these processes are like those found in other mammals. As a result of the successive divisions of the ovum in segmentation, a spherical mass of cells, the morula (fig. 7) is formed. In this mass, an excentric cavity forms (fig. 8) whereby the mass is transformed into a hollow vesicle. The wall of this vesicle is probably formed throughout the greater part of its extent by a single layer of cejls; but at one point of the circumference there is a group of cells termed the inner cell mass (fig. 8). Probably about this time the ovum enters the uterine cavity, and through the activity of the outer layer of ceUs {trophoblasi) becomes embedded in the uterine mucosa.
embryos which have been described, development has already proceeded beyond
Fig. 9. — Diagram Showing the Relations of the Germ Layers in an Early EimRYO. Ac, amniotic cavity, lined by ectoderm. D, yolk-sac, lined by endoderm (En). Me, Me', mesoderm, C, extra,-embryonic calom. B, chorion. T, trophoblast. (McMurrich.)
■cavity; the deeper (D) is the cavity of the yolk-sac; while between them is a plate of cells forming the embryonic disc. The embryonic disc (figs. 9 and 10) contains three layers of cells, — the fundamental germ layers, — ectoderm (Ec), endoderm (En), &n.A mesoderm.
The germ layers of the embryonic disc are of prime importance in the development of the body. From the ectoderm, which hes next to the amniotic cavity and represents the upper (later outer) germ layer, are derived the epidermis and the entire nervous system. From the ■endoderm, which hes next to the yolk-sac, and represents the lower (later inner) germ layer, is derived the epithehal lining of the digestive mucosa and its derivatives. From the mesoderm, or middle germ layer, is differentiated the remainder of the body, including the skeletal and supporting tissues, vascular system, muscle and most of the urogenital organs.
Endoderm
later becomes separated from the chorion, is composed of mesoderm lined by endoderm. The outer cell layers form the chorion, which likewise shows two layers, the outermost of which (trophoblast) is ectoderm, the inner, mesoderm. In fig. 10 the chorion is beginning to send out root-like projections (villi) which invade the uterine mucosa.
It is thus noteworthy that of the cells']derived from the ovum relatively only a few — those of the embryonic disc — enter directly into the formation of the body. The yolk-sac, a rudimentary organ of phylogenetic significance, is later chiefly absorbed, although the proximal portion may enter slightly into the formation of the intestinal wall. The amnion is a protective membrane, while the chorion forms the foetal part of the placenta.
Development of the embryonic disc. — When first formed, the surface of the embryonic disc shows no trace of differentiation. A slightly later but still comparatively early stage in its development is shown in fig. 11. It is here
Fig. 11.- — Model Showing the Embryonic Disc from an Embryo 1.17 mm. In Length. Viewed from above and laterally, the roof of the amniotic cavity having been removed, n, primitive pit (neurenteric canal), pg, primitive groove, mg, neural groove, b, body-stalk. (McMurrich. from Frassi.)
viewed from above, the amnion having been removed. The disc is an elliptical plate, whose long axis represents the mid-line of the embryo. Near the center is a small rounded depression, the primitive pit. Extending backward (toward the tail end of the embryo) from this is a dark line, the 'primitive streak, corresponding to a groove, the primitive groove. Extending forward from the primitive pit is an indistinct wide shallow groove, the neural groove.
embryonic disc.
At the anterior end of the primitive streak this proliferation extends forward as a plate of cells, the so-called 'head process.' The axial portion of this process is the anlage of the rtotochord, the embryonic skeletal axis. It contains a canal, which opens into the primitive pit. The notochordal anlage soon fuses with the underlyiag endoderm, and its canal forms the transient neurenteric canal.
In the mid-line anterior to the primitive streak there appears the shallow neural groove (fig. 11), corresponding to a thickened plate of ectodermic cells, the neural plate. The neural groove is slightly forked at its posterior extremity, in the region of the primiiive node (Hensen's node), which forms the dorsal lip of the primitive pit. As development proceeds, the neural plate extends posteriorly, and the primitive pit is accordingly shifted backward, the corresponding part of the primitive groove being converted into 'head process.' The primitive streak thus becomes progressively shortened (cf. figs. 11 and 13).
L, lower limb.
Topography of the embryonic disc. — Although only slight signs of differentiation are visible in the embryonic disc at the stage shown in fig. 11, it is already possible to map out more or less definite areas corresponding to all the various regions of the future body, as shown in fig. 12.
The cervical, thoracic, lumbar and sacro-coccygeal regions appear successively smaller, approaching the posterior end ('tail bud') of the primitive streak. It is also a striking fact that the future dorsal region of the body wall, corresponding to the central portion of the disc, along each side of the mid-line, is now larger than the ventro-lateral regions, which occupy a relatively narrow area around the periphery of the disc.
The topography of the germinal areas in the embryonic disc shown in fig. 12 is based partly upon a study of the succeeding stages of development, and partly upon the results of experiments upon the germinal disc in lower forms, especially in the chick (Assheton, Peebles, Kopsch).
Law of developmental direction. — In the relative size of the various embryonic areas is foreshadowed what may be termed the law of direction in development. In general it is found that development (including growth and differentiation) in
Chorion with villi
the long axis of the body appears first in the head region and progresses toward the tail region. Similarly in the transverse plane development begins in the mid-dorsal region and progresses latero-ventrally (in the limbs, proximo-distally). These principles are of great importance in morphogenesis.
The law of developmental direction is also probably of phylogenetic significance. The cranio-caudal direction of development is in accordance with the theory that the head is the most primitive portion of the body, and hence precocious in development. The trunk is perhaps a secondary acquisition, hence arising as an extension of the primitive head region.
DERIVATION OF BODY TUBE FROM EMBRYONIC DISC 13
The dorso-ventral direction of development, together with the plate-hke form of the embryonic disc, has a different phylogenetio significance. Both are probably inherited from an ancestral type with a yolk-laden ovum. In such an ovum, with the meroblastic type of segmentatien, the flattened embryonic disc gradually spreads from the dorsal surface in a ventral direction around the underlying yolk-mass.
Derivation of body tube from embryonic disc. — ^The primary result of the precocious growth in the dorsal region of the embryonic disc is the conversion of the disc into the body tube, curved ventrally in its long axis (fig. 14).
Fig. 15. — ■Portion op Cross Section of the Embryo shown in Fig. 13. ch, notochord. ct, somatic mesoderm, df, splanchnic mesoderm, g, junction of extra-embryonic somatic and splanchnic mesoderm, ek, ectoderm, en, endoderm. me, embryonic mesoderm. /, neural groove, p, beginning of embryonic coelom (pericardial cavity). (Minot, after Graf Spee.)
As a result of the more rapid expansion of the germ layers (especially the ectoderm) near the mid-line, the dorsal surface of the embryonic disc in general becomes convex, with a depression laterally (where growth is less rapid) forming a groove at the line of attachment of the amnion (figs. 11,12, 13, 14 B). The unequal growth in the germ layers is clearly evident in the cross section shown in fig. 15. By a continuation of this process, the margins of the embryonic disc become still further depressed and finally folded in ventrally so as to transform the disc into a tube (fig. 14 D). Similarly, by a more rapid expansion of the dorsal layer of the disc in the longitudinal axis, the head and tail ends of the disc are folded and tucked in ventrally, and the primitive body tube is thus correspondingly curved in its long axis (figs. 14 A, 14 C).
Fig. 16. — Model op Human Embryo 1.8 mm. Long. Viewed from above, the roof of the amniotic cavity having veen removed. Near the caudal end of the neural groove, the primitive pit (opening of neurenteric canal) is visible. The primitive somites are appearing in the occipital region, the fourth corresponding to the boundary between head and neck. (McMurrich, from Keibel and Elze.)
The embryonic disc is thus converted into a tube composed of an outer layer of ectoderm, a middle layer of mesoderm and an inner layer of endoderm. The yolk-sac now presents an expanded yolk-vesicle fined by endoderm which is still continuous through the constricted yolkstalk with the endoderm lining the primitive enteric cavity (fig. 14 C). The enteric cavity (or archenteron) has a bhnd tubular prolongation (fore gut) into the head region, and another (hind gut) into the tail region. From the latter a slender diverticulum, the allantois, extends into the body stalk (later the umbiUcal cord). The allantois is an organ of phylogenetic importance, with which the urinary bladder is later connected.
Formation of the neural tube. — The principle of unequal growth applies to the formation not only of the body as a whole, but also of its constituent parts. Thus the anlage of the nervous system arises from the ectoderm as a wide groove
whose edges (neural ridges) by local growth are folded upward so as to meet in the mid-line where they fuse, thus transforming the groove into the neural tube (fi*gs. 11, 12, 13, 15, 16, 17, 18).
The closure begins, not at the anterior end (as might be expected from the general law of cranio-oaudal development), but in the cervical region, extending forward into the brain region, and backward along the spinal cord. Thus the extreme ends (anterior and posterior neuropores) are the last to close.
The precocious and energetic growth of the neural anlage is largely responsible for the ventral flexure of the embryonic body axis, especially in the head region, where the flexures of the brain are very conspicuous (figs. 22, 26).
With the closure of the neural tube dorsally and of the aUmentary canal ventraUy the human embryo assumes the typical vertebrate form. The cyhndrioal body wall now encloses two tubes (neural and enteric) with the longitudinal axis (notochord) between them (figs. 18, 24).
After the embryonic disc has been transformed into a tube, the body of the human embryo in cross section appears not circular but elongated dorso-ventrally. This is the typical form for vertebrates with horizontal body axis. In later foetal stages, the body becomes more rounded in cross section, and finally, with the assumption of the erect posture in postnatal life, becomes decidedly flattened dorso-ventrally (figs. 20, 21).
Medullary canal
Development of the mesoderm. — The mesodermic layer on each side of the notochord in the embryonic disc develops in two divisions. The medial (or dorsal) divisions form a series of hollow segments, the somites (figs. 16, 17, 18). The lateral (later ventral) divisions each spht into an upper (outer) or somatic layer and a lower (inner) or visceral layer. When the embryonic disc becomes folded, the corresponding somatic and visceral layers unite ventrally and enclose between them the common cmlom or primitive body cavity (fig. 18).
(As previously noted, the mesoderm arises chiefly from the lateral portions of the 'head process.' A comparatively early stage before the appearance of the somites is shown m cross section in fig. 15. The somites appear first in the occipital region, and rapidly differentiate successively in the cranio-oaudal direction (figs. 16, 17, 22). In embryos 7 or 8 mm. in length, about 40 somites may be distinguished, 3 to 5 occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 5 or 6 coccygeal (in the rudimentary tail region).
secondarily divided into the permanent pericardial, pleural and peritoneal cavities.
The outer layer of the lateral mesodermic division forms the somatic or parietal layer of the peritoneum, etc. The inner layer forms the visceral or splanchnic layer, and develops not only the serous membrane, but also the muscular and connective tissue of the walls of the alimentarj' canal and its derivatives.
somatic layer
segments or metameres. Each somite develops a primitive muscle segment, myotome, and a skeletal segment, sclerotome (figs. 18, 19). Moreover, the corresponding nerves and .blood-vessels likewise assume a metameric arrangement. This metamerism persists (more or less modified) in the adult neck and trunk.
somite forms the sclerotome. Its cells migrate to form the corresponding vertebra, rib, etc., as
Fig. 19. — Diagrams Illustrating the History of the Mesoderm. M, myotome, dM, dorsal portion of myotome. vM, ventral portion of myotome. SC, sclerotome, gr, genital ridge. PFd, Wolffian duct. iSm, somatic layer of mesoderm, bto, visceral layer of mesoderm. mr, membrana reuniens. I, intestine. A'', neural tube. (MoMurrich.)
well as the mesenchyme forming the various connective tissues in this region. The remainder of the somite forms the myotome, from which the voluntary musculature of the trunk, the neck and (in part) the head is derived. The dorsal portions of the myotomes develop the muscle in the dorsal region of the trunk, while the ventral portions extend ventralward to form the musculature of the latero-ventral body walls (figs. 19, 20, 21, 23).
tissue, etc.
As development proceeds, the metamerism of the muscles and arteries becomes more or less obscured, but that of the vertebrfe and nerves is fully retained even in the adult. In the case of the muscle plates, from which all the voluntary musculature of the trunk is derived, great modifications occur. Extensive fusion of successive plates occurs, the intervening connective tissue disappearing more or less completely; associated with this fusion there is longitudinal and tangential splitting of the somites to form individual muscles; and portions of some of the plates may wander far from their original position. But notwithstanding these complicated changes, indications of the primary metameric arrangement of the muscle plates are abundant, and even in the most e.xtreme cases of modification the developmental history of a muscle can be determined by means of its nerve supply. For the fibres derived from each plate will usually retain, up matter what changes of independence or position they may undergo, the innervation by their originally corresponding segmental nerve; so that the occurence in the lumbar region of the body of muscle-fibres (the diaphragm) supplied by nerve-fibres from a cervical nerve is evidence that the muscle-fibres have been derived from a cervical mesodermic somite and have subsequently migrated to the position they finally occupy.
As regards the arteries, they arise primarily from a longitudinal stem, the aorta, in a strictly segmental manner, each metamere having distributed to it two pairs of arteries and a single median one (fig. 20). One pair of arteries supplies the body wall, and these retain very distinctly their original metameric arrangement; the other pair passes to the paired viscera, such as the lungs, kidneys, ovaries (or testes), so many of the pairs disappearing, however, that their metameric arrangement is not very evident in the adult. The unpaired vessels supply the digestive tract and its unpaired appendages, such as the liver and pancreas, and undergo great modifications, those of the lower thoracic and lumbar regions becoming reduced by fusion and degeneration to three main trunks.
Branchiomerism. — Throughout the trunk and neck regions, then, a fundamental metameric plan underlies and determines the arrangement of many parts. In the head there is also evident a primary arrangement of the parts in succession; but this arrangement appears to be somewhat different from that of the trunk in that it involves the ventral instead of the dorsal mesoderm and is associated with the occurrence of branchial arches rather than with true mesodermic somites. It is consequently termed branchiomerism.
Not but that there are also indications of metamerism in the head, the muscles of the orbit, and the majority of the extrinsic muscles of the tongue, together with the nerves supplying these muscles, being apparently metameric structures, but the metamerism of this region of the body is largely overshadowed by the branchiomerism.
DEVELOPMENT OF THE SOMITES
and sections will show that similar and corresponding grooves also occur upon the inner surface of the pharyngeal wall. These are the branchial grooves, and since they are four in number (with a rudimentary fifth) in the human embryo, they mark off five branchial (or visceral) arches, the first of which hes between the oral depression and the first branchial groove, while the fifth is situated behind the fourth groove. These branchial arches are so named because they represent the arches which (excepting the first) support the gills (branchise) in the lower vertebrates, the grooves representing the branchial slits, even although they do not become perforated in the human embryo.
Each branchiomere consists of an axial skeletal structure, of muscles which act on this skeleton, of a nerve which supphes the muscles and the neighbouring integument and mucous membrane, and of an artery which carries blood to all these structures. The arches, however, do npt in the human embryo retain their original branchial function, but undergo extensive modifications, becoming adapted to various functions and showing less in the adult of their originally simple arrangement than do the metameres. Nevertheless no matter what modifications the musculature of any arch may undergo, it will retain its original innervation and, to a large extent, its relations to the skeletal elements of its arch; and even the arteries in their distribution show clear indications of being arranged in correspondence to the various arches.
» Branchial grooves. — Of the external branchial grooves, the first (lying between mandibular and hyoid arches) becomes deepened to form the external auditory meatus, the margins becoming elevated to form the auricle (fig. 26). The region corresponding to the second, third and fourth external grooves becomes depressed, forming the sinus cervicalis, which soon closes up and disappears.
lined with endoderm. The first internal groove becomes transformed into the auditory (Eustachian) lube, tympanic cavity, etc. The second internal groove persists in part as the fossa of the palatine tonsil. The third and fourth grooves are probably represented in part by the vallecula and recessus piriformis, detached portions of their lining endoderm giving rise to the thymus, parathyreoid glands, etc. The rudimentary fifth groove is said to give rise to the ultimobranchial body, a structure of uncertain significance (fig. 27).
Development of the face, — -The facial region is at first relatively small. It includes the sense organs (eye, ear, nose) and mouth region. Some of the more important developmental features may be briefly mentioned. In an embryo of the sixth week (fig. 28) the wide mouth aperture is seen to be bounded below (posteriorly) by the lower (mandibular) portion of the
Mesodermic somite
first arch, laterally^by the upper (maxillary) process of the first arch. Above it is bounded by a median plate, the nasal process, which on either side forms a protuberance, the globular process. Lateral to the globular process is a rounded depression, the nasal pit. The maxillary process extends forward and fuses with the globular process to form the upper jaw region (failure to unite resulting in the malformation known as 'hare-lip'). The nose is at first broad, due to the width of the nasal process, which later becomes the nasal septum (fig. 29). The nasal pits deepen and later acquire openings into the primitive mouth cavity.
The viscera. — The structures so far considered belong, for the most part, to the body wall; it remains to consider the general plan of arrangement of the viscera. It has been pointed out that the body may be regarded as a cylinder enclosing two tubes, one of which constitutes the central nervous system and the
THE VISCERA
other the digestive tract. The latter may be regarded as being primarily a straight tube traversing lengthwise the body cavity enclosed by the body wall (figs. 18, 20). The layers of both the visceral and somatic plates which im-
Peritoneal cavity
mediately enclose the body cavity become transformed into a characteristic pleuro-peritoneal membrane. Near the mid-dorsal line, a vertical double plate of peritoneum extends ventrally connecting the somatic (parietal) and visceral layers of peritoneum, and constituting what is termed the mesentery (fig. 20).
Fig. 24. — Diagram Illustrating the Recession of the JDiaphragm (Septum Transversum) IN the Human Embryo. On the right are indicated the vertebral levels; on the left, the position of the septum transversum in a series of embryos from 2 mm. (XII) to 24 mm. (VI) in length, pp, pleuro-peritoneal cavity. (Mall.)
_ As development proceeds the digestive tract grows in length more rapidly than the cavity which contains it, and so gradually becomes thrown into numerous coils in the abdominal region, these changes leading to numerous modifications of the original arrangement of the mesentery. These will be described later on in the section on the digestive system. Several outgrowths also arise from the primitive digestive tract, to form important organs, such as the lungs,
the liver, the pancreas and the urinary bladder; and, with the exception of the bladder, each of^these becomes completely invested by primitive peritoneum. In the case of the liver this original condition is practically retained, but the investment of the pancreas later becomes a partial one on account of the modifications which ensue in the mesentery. The bladder has only a portion of its surface in contact with the peritoneum, but the investment of the lungs remains complete, each lung, indeed, appropriating to itself the entire visceral layer' of its half of the thorax, with the exception of a small ventral portion which forms the investment of the heart. Furthermore, the cavities which surround each of the three organs named, the two lungs and the heart, become completely separated from one another; and since each investment consists of a visceral and a parietal layer, each of the organs is enclosed within a double-waUed sac, which in the case of each lung forms its pleura, while that of the heart is known as the pericardium. The spaces which occur within the thorax between the pleurte of the two sides are known as the mediastina, which include the heart, oesophagus, etc. (fig 21).
Tn addition to the viscera mentioned there are some organs, such as the spleen and genitourinary organs, which are developments of the mesoderm, the spleen arising in the mesentery which passes to the stomach and the genito-urinary organs primarily from the intermediate cell mass. The morphogeny of these structures and also of the vascular system, nervous system, and sense organs will be considered later in connection with their structure.
Recession of the diaphragm and heart. — In the early stages of development the heart is situated far forward, in what will eventually be the pharyngeal region (figs. 12, 17). Just behind (caudal to) the heart, between it and the yolksac, is a plate of connective tissue, the septum transversum, which serves for the passage of large veins from the body wall to the heart (figs. 17, 23). This septum together with certain accessory structures eventually gives rise to the diaphragm, which becomes a complete partition separating the thoracic and abdominal portions of the body cavity.
The diaphragm and heart are therefore originally situated far above (cranial to) their final position and recede in the course of development, producing an elongation of the vessels and nerves associated with them and forcing downward such organs as the stomach and liver (fig. 24). The chief factor in this displacement is probably the ventral head flexion and the precocious growth and expansion of the organs in the head region. The effects of this recession are especially noticeable in the nerves, these passing to the various organs concerned arising from a much higher level than that occupied by the organs. The nerve to the diaphragm, for instance, comes from the fourth cervical segment, those passing to the cardiac and pulmonary plexuses from the cervical region, and those to the plexus in relation with the stomach, liver and adjacent organs from the thoracic region. The blood-vessels, however, may shift their origins from the main trunks by successive anastomotic roots, so that in general they keep pace with the viscera in the migration caudalward.
The limbs. — Each limb at its first appearance (fig. 22) is a flat, plate-like outgrowth from the side of the body, and consists of an axial mass (blastema) of mesodermic tissue from which the limb skeleton will develop, and, surrounding this, a layer, also of mesodermic tissue, from which the muscles and blood-vessels will arise. It is as yet uncertain whether the muscle blastema is derived from the myotomes (as in lower vertebrates) or whether it develops from the mesenchyme.
THE Extremities. M, mandibular arch.
Fig. 27. — Diagram to Show the Derivatives op the Branchial Clefts. le, lie, Ille, IVe, Ve, external branchial grooves, li, Hi, llli, IVi, Yi, internal branchial grooves. Tons., palatine tonsil. Ep III, Ep IV, epithelial bodies. Ub, ultimobranchial body. Th.^ 'thyreoid D.th. gl., ductus thyreoglossus. (Modified rom Keibel and Mall.)
At first each limb plate is so placed that one of its surfaces looks dorsally and the other ventrally, and one border (that corresponding to the thumb or great toe) is anterior (i. e., cranial) and the other posterior (caudal). Later, however, each limb becomes bent caudally through about ninety degrees, so that the limbs whose long axes were at first at right angles to the long axis of the body come to he parallel to that axis. In addition there occurs a rotation of each fore-limb in such a manner that the thumb turns latero-dorsally, while in the lower Umb the direction of the movement is exactly the opposite, the great toe turning ventro-medially. As a result there is an apparent reversal of the surfaces in the two limbs, the flexor muscles of the arm reaching on the surface which is directed anteriorly, while in the lower limb the corresponding muscles occupy the posterior surface. The dorsum of the foot and the great toe side correspond respectively to the back and thumb side of the hand, the tibia corresponds to the radius and the fibula to the ulna. The limb anlage soon becomes divided into three primary segments. The distal segment (hand or foot) is a flattened rounded disc, in which the digits soon appear (fig. 26). The proximal portion forms the forearm or leg and the arm or thigh. In general, the extremities follow the law of cranio-caudal and dorso-ventral (proximo-distal) development.
Prenatal growth. — The prenatal growth of the human body in length and weight is indicated in the preceding table. According to Hasse, the age of the foetus may be estimated from its total length as follows. Before the fifth month, the square of the age in (lunar) months gives the length in centimetres. After this, the age in months multiphed by five gives the length. This gives approximate results, except for the first month.
While the growth in absolute weight increases from month to month, it is important to note that the real (relative) growth rate rapidly diminishes. The ovum increases in weight during the first month about 1000 times, or 100,000 per cent, (not including the extra-embryonic structures). This rate diminishes rapidly, however, so that the increase during the last foetal month is only about 33 per cent.
The following chart is based upon data from Camerer (1-5 yrs.). Porter (6-17 yrs.), and Roberts (18-20 yrs.), showing the average postnatal growth in height and weight by sexes. The average height at birth is about 50 cm. (20 inches) ; weight, about 3200 g. (7 pounds). The male is slightly heavier and taller than the female, except during the acceleration at the period
of puberty. Puberty occurs earlier in the female, so that between the ages of 12 and 15 the girls exceed the boys in average height and weight. With the exception of this period of acceleration, the (relative) growth rate in general diminishes steadily from birth, and has practically ceased at 20 years. The average height at this time is about 160 cm. (5 ft., 3 in.) in the female, and 170 cm. (5 ft., 7 in.) in the male; average weight, about 56 kilograms (126 lbs.) in the female, and 65 kilograms (146 lbs.) in the male. Under favourable conditions, growth in height may continue slowly up to about 25 years, and in weight even longer; but in old age there is a slight decrease in both height and weight.
The following measurements (from Holt, "Diseases of Infancy and Childhood" may be taken as a normal average standard of growth during the first three years. The weights are taken without clothing. The height is taken by placing the baby on a perfectly flat surface like a table, and having some one hold the child's knee down so that he hes out straight, then taking a tape-measure and measuring from the top of his head to the bottom of his foot, holding the tape line absolutely straight. The chest is measured by means of a tape line passed directly over the nipples around the child's body and midway between full inspiration and full expiration. The head measurement is taken directly around the circumference of the head, over the forehead and occipital bone.
shown in fig. 31. It will be noted that the changes are in accordance with the law of developmental direction previously explained, the growth impulse passing along the body in a cranio-caudal direction.
The head is therefore largest in the earlier stages, forming about half the body, decreasing to 25 per cent, in the newborn, and to 7 or 8 per cent, of the body in the adult. The upper limbs increase to about 10 per cent, of the body at birth, maintaining thereafter about the same relative size. The trunk as a whole remains of about the same relative size (about 45 per cent.).
VARIABILITY 25
although the thoracic portion reaches its maximum in the earher stages, and the pelvic portion not until adult life. The loiver limbs, Uke the pelvis, develop slowly, forming about 20 per cent, of the body at birth and reaching 35 per cent, in the adult.
Relative growth of the systems. — There is also a marked difference in the relative growth of the various systems. Data for the skin and skeleton are somewhat scanty and unsatisfactory. The musculature, however, is relatively small in the embryo, increasing to about 25 per cent, of the body in the newborn, and to 40 or 45 per cent, in the adult. The visceral group (including brain and spinal cord), on the other hand, is relatively largest in the early embryo, decreasing from about 35 per cent, of the body to about 24 per cent, in the newborn and to about 10 per cent, in the adult.
Relative growth of the organs. — While in general, the individual organs follow the course of relative growth of the visceral group, each organ has its own characteristic course of growth. As a rule, after its appearance in the embryo, each organ increases more or less rapidly to its maximum relative size, after which, although increasing in absolute size, it decreases in relative size through subsequent prenatal and postnatal life up to the adult.
Thus the brain in the embryo of the second month forms more than 20 per cent, of the body, but steadily declines to about 13 or 14 per cent, in the newborn, and about 2 per cent, in the adult. The spinal cord and eyeballs have a similar course of growth. The heai-t declines from about 5 per cent, of the body in the embryo of the second month to about .75 per cent, in the newborn and .46 per cent, in the adult. The liver decreases from a maximum of nearly 10 per cent, in the thh-d month to 5 per cent, in the newborn and 2.7 per cent in the adult. The suprarenal glands decrease from about .46 per cent, of the body in the third month to .23 per cent, in the newborn and .01 per cent, in the adult. The lungs decrease from 3.3 per cent, in the fourth month to about 2 per cent, of the body at birth and 1 per cent, (bloodless weight) in the adult. The kidneys reach a maximum of about 1 per cent, of the body toward the end of thefcetal period, decreasing to about .46 per cent, in the adult. The thymus, thyroid, spleen and alimentary canal likewise reach their maximum slowly, being probably relatively largest about the time of birth. The ovary and testis, however, appear to be relatively largest during the prenatal period.
Variability. — It must be borne in mind that all statements concerning structure refer to the average or norin, and are always subject to variation. This is. therefore a topic of importance to students of anatomy. Variations are classified as either germinal or somatic.
Germinal variations are due to fundamental differences in the germ plasm, and are transmitted by heredity. These include many of the characters whereby one individual differs from another. Variations according to sex are included under this class. Variations inherited from, more or less remote ancestors are termed atavistic or reversional.
Somatic variations, or 'acquired characters,' are due to environmental influences, such as nutrition, temperature, shelter, disease, training, etc. While somatic variations may be very great, they do not affect the germ plasm and are not transmitted by heredity.
In many cases it is exceedingly difficult to distinguish germinal from somatic variations Size, for example, may be due to either or both. Moreover, somatic variations may be produced at any time after the fertilisation of the ovum. Very slight environmental changes are sometimes sufficient to produce a marked effect upon the dehcately balanced mechanism of the developing embryo. Malformations and pathological conditions are thus often to be explained. As to the extent of variability, some characters are much more variable than others. Height, for exahiple, is less variable than weight. Moreover, variability differs in the various parts and organs. In general, the head and head organs are less variable than the remainder of the body. The skeleton and musculature appear less variable than the integument and viscera.
on genetics and biometrical statistics.
'Reieiences.—Embnjology: Keibel and Mall, Human Embryology (2 vols.); Bryce, Quain's Anatomy, 11th ed., vol. 1 ; Minot, Laboratory Text-book of Embryology; McMurrich, Development of the Human Body. Growth: Minot, Age, Growth, and Death; Jackson, Amer. Jour. Anat., vol. 9; Anat. Record, vol. 3. Heredity: Davenport, Heredity and Eugenics; Walter, Genetics. Biometry: Davenport, Statistical Methods; Yule, Theory of Statistics.
By peter THOMPSON, M.D.,
PROFESSOR OF ANATOMY IN THE UNIVEIlSITr OF BIRMINQHAM; EXAMINER IN ANATOMY, THE HNIVERSITY [^CAMBRIDGE; FORMERLY EXAMINER IN ANATOMY FOR THE UNIVERSITIES OF LOMDON, ABERDEEN, MANC DUBLIN AND FOR THE CONJOINT BOARD OF ENGLAND
THE SKELETON
THE skeleton forms the solid framework of the body, and is composed of bones, and in certain parts, of pieces of cartilage. The various bones and cartilages are united by means of ligaments, and are so arranged as to give the body definite shape, protect from injury the more important delicate organs, and afford attachment to the muscles by which the various movements are accomplished.
In its widest acceptance, the term skeleton includes all parts of the framework, whether internal or external, and as in many of the lower animals there are, in addition to the deeper osseous parts, hardened structures associated with the integument, it is convenient to refer to the two groups as endoskeleton and exoskeleton or dermal skeleton, respectively. All vertebrate— i. e., back-boned — animals ])o,sscss an endoskeleton, and many of them a well-developed exoskeleton also, but in maniiiials, the highest group of vertebrates, the external skeleton, when it exists, plays a relatively subordinate part. In most of the invertebrates the endoskeleton is absent and the dermal skeleton alone is found.
salts.
The number of bones in the skeleton varies at different ages, some, which are originally quite independent, becoming united as age advances. They are arranged in an axial set, which includes the vertebral column, the skull, the ribs, and the sternum, and an appendicular set, belonging to the limbs. The following table shows the number of bones usually distinct in middle Hfe, excluding the auditory ossicles: —
Total 200
Several of the skull bones are compound, i. e., in the immature skeleton they consist of separate elements which ultimately unite to form a single bone. In order to comprehend the nature of such bones it is advantageous to study them in the various stages through which they pass in the process of development in the foetus and the cliild.'
It follows, therefore, that to appreciate the morphology of the skeleton — i. e., the history of the osteological units of which it is composed — the osteogenesis or mode of development of the bones must be studied, as well as their topography or position.
Some bones arise by ossification in membrane, others in cartilage. In the embryo, many portions of the skeleton are represented by cartilage which may become infiltrated by lime salts — calcification. This earthy material is taken up and redeposited in a regular mannerossification. Portions of the original cartilage persist at the articular ends of bones, and, in
young bones, at the epiphysial lines, i. e., the lines of junction of the main part of a bone with the extremities or epiphyses. Long bones increase in length at the epiphysial cartilages, and increase in thickness by ossification of the deeper layers of the investing membrane or periosteum. These processes — intracartilaginous and intramembranous ossification — proceed concurrently in the limb-bones of a young and growing mammal.
There is no bone in the human skeleton which, though pre-formed in cartilage, is perfected in this tissue. The ossification is completed in membrane. On the other hand, there are numerous instances in the skull, of bones the ossification of which begins in, and is perfected by, the intramembranous method. Ossification in a few instances commences in membrane, but later invades tracts of cartilage; occasionally the process begins in the perichondrium and remains restricted to it, never invading the underlying cartilage, which gradually disappears as the result of continued pressure exerted upon it by the growing bone. The vomer and nasal bones are the best examples of this mode of development. Further details of development and ossification are included in the description of each bone.
The limb-bones differ in several important particulars from those of the skull. Some of the long bones have many centres of ossification, but these have not the same significance as those of the skull. It is convenient to group the centres into two sets, primary and secondary. The primary nucleus of a long bone appears quite early in f cetal life, and the main part (shaft) thus formed is called the diaphysis. In only three instances does a secondary centre appear before birth, e. g., the lower end of the femur, the head of the tibia, and occasionally the head of the humerus. Many primary ossific nuclei appear after birth, e. g., those for the carpal bones, the cuneiform and navicular bones of the foot, the coracoid process of the scapula, and for the third, fourth, and fifth pieces of the sternum.
When a bone ossifies from one nucleus only, this nucleus may appear before or after birth. Examples: the talus (astragalus) at the seventh month of foetal life, and the lesser multangular (trapezoid) at the eighth year. When a bone possesses one or more secondary centres, the primary nucleus, as a rule, appears early. Examples: the femur, humerus, phalanges, and the calcaneus.
Secondary centres which remain for a time distinct from the main portion of a bone are termed epiphyses. An epiphysis may arise from a single nucleus, as is the case at the lower end of the femur, or from several, as at the upper end of the humerus. Prominences about the ends of long bones may be capped by separate epiphyses, as illustrated at the upper end of the femur.
According to Professor F. G. Parsons, there are at least three kinds of epiphyses: — (1) Those which appear at the articular ends of long bones, which, since they transmit the weight of the body from bone to bone, may be termed pressure epiphyses. (2) Those which appear as knob-like processes, where important muscles are attached to bones; and as these are concerned with the pull of muscles, they may be described as traction epiphyses. (3) The third kind includes those epiphyses which represent parts of the skeleton at one time of functional importance but which, having lost their function, have now become fused with neighbouring bones and only appear as separate ossifications in early life. These may be termed atavistic epiphyses and include such epiphyses as the tuberosity of the ischium, the representative of the hypoischium of reptiles.
1. Those epiphyses whose centres of ossification appear last are the first to unite with the shaft. There is one exception, however, to this statement, viz., the upper end of the fibula, which is the last to unite with the shaft, although its centre appears two years after that for the lower end. This may perhaps be accounted for by the rudimentary nature of the proximal end of the fibula in man and many other mammals.
2. The epiphysis toward which the nutrient artery is directed is the first to be united with the shaft. It is also found that while the increase in length of the long bones takes place at the epiphysiai cartilages, the growth takes place more rapidly and is continued for a longer period at the end where the epiphysis is the last to unite. It follows, therefore, that the shifting of the investing periosteum, which results from these two factors, leads to obliquity of the vascular canal by drawing the proximal portion of the nutrient artery toward the more rapidly growing end. Moreover, when a bone has only one epiphysis, the nutrient artery will be directed toward the extremity which has no epiphysis.
the shaft and epiphysis consolidate, e. g., the upper end of the humerus.
On section, the shaft of a f cetal long bone is seen to be occupied by red marrow lodged in bony cells which do not present any definite arrangement. The expanded ends of the bones contain a network of cancellous tissue, the intervals being filled with red marrow. This cancellous tissue differs from that of the foetal bone in being arranged in a definite manner according to the direction of pressure exerted by the weight of the body, and the tension produced by the muscles. The arrangement of the cancelli in consequence of the mechanical conditions to which bones are subject is noticed in the description of a vertebra, the femur, and the humerus.
Bones are divisible into four classes: — long, short, flat, and irregular. The long bones, found chiefly in the limbs, form a system of levers sustaining the weight of the trunk and providing the means of locomotion. The short bones, illustrated by those of the carpus and tarsus, are found mainly where compactness, elasticity, and Umited motion are the principal requirements. Flat bones confer protection or provide broad surfaces for muscular attachment, as in the case of the cranial bones and the shoulder-blade. Lastly, the irregular or mixed bones constitute a group of peculiar form, often very complex, which cannot be included under either of the preceding heads. These are the vertebrae, sacrum, coccyx, and many of the bones of the skull.
THE VERTEBRAL COLUMN
The shafts ot long bones at the time of birth are mainly cylindrical and free from ridges. The majority of the lines and ridges so conspicuous on the shafts of long bones in adults are due to the ossification of muscle-attachments. The more developed the muscles, the better marked the ridges become.
The surfaces of bones are variously modified by environing conditions. Pressure at the •extremities causes enlargement, and movement renders them smooth. The two causes combined produce an articular surface. When rounded and supported upon a constricted portion of bone, -an articular surface is termed a head, sometimes a condyle ; when depressed, a glenoid fossa. Blunt, non-articular processes are called tuberosities; smaller ones, tubercles; sharp projections, spines. Slightly elevated ridges of bones are crests; when narrow and pronounced, lines and
The vertebral column [columna vertebralis] consists of a series of bones called vertebrae, closely connected by means of fibrous and elastic structures, which allow of a certain but limited amount' of motion between them. In the young
subject the vertebrse are thirty-three in number. Of these, the upper twentyfour remain separate throughout life, and are distinguished as movable or true vertebrae. The succeeding five vertebrae become consolidated in the adult to form one mass, called the sacrum, and at the terminal part of the column are four rudimentary vertebrae, which also tend to become united as age advances, to form the coccyx. The lower nine vertebrae thus lose their mobihty as individual bones, and are accordingly known as the fixed or false vertebrae. Of the true vertebrae, the first seven are called cervical [cervicales], the succeeding twelve thoracic [thoracales] or dorsal, and the remaining five lumbar [lumbales].
Although the vertebrae of the different regions of the coliunn differ markedly in many respects, each vertebra is constructed on a common plan, which is more or less modified in different regions to meet special requirements. The essential characters are well seen in the vertebrae near the middle of the thoracic region, and it will be advantageous to commence the study of the vertebral structures with one selected from this region.
The body [corpus vertebrae] or centrum is a soUd disc of bone, somewhat heart-shaped, deeper behind than in front, slightly concave on its superior and inferior surfaces, and wider transversely than antero-posteriorly. The upper and lower surfaces are rough' for the intervertebral discs which are interposed between the bodies of the vertebrae, and the margins are slightly lipped. The circumference of the body is concave from above downward in front, convex fron side to side, and perforated by numerous vascular foramina. Posteriorly it is concave from side to side and presents one or two large foramina for the exit of veins from the cancellous tissue. On each side of the body, at the place where it joins the arch, are two costal pits (superior and inferior) [fovea costalis superior; inferior] placed at the upper and lower borders, and when two vertebrae are superimposed, the adjacent costal pits form a complete articular pit for the head of a rib. The superior and inferior costal pits were formerly designated as " demi-f acets. "
The arch [arcus vertebrae] is formed by two pedicles and two laminae, and supports seven processes — one spinous, two transverse, and four articular. The pedicles or roots of the vertebral arch [radices arcus vertebrae] are two short, constricted columns of bone, projecting horizontally backward from the posterior surface of the body. The concavities on the upper and lower borders of each pedicle, of which the lower is much the deeper, are named vertebral notches [incisurae], and when two vertebrae are in position, the notches are converted into intervertebral foramina for the transmission of the spinal nerves and blood-vessels.
The laminae are two broad plates of bone which connect the spinous process with the roots (pedicles) and complete the arch posteriorly. The superior border and the lower part of the anterior surface of each lamina is rough for the insertion of the ligamenta flava. The upper part of the anterior surface is smooth where it forms the posterior boundary of the vertebral canal. When articulated, the
somewhat like tiles on a roof.
The spinous process [processus spinosus], long and three-sided, projects backward and downward from the centre of the arch and terminates in a slight tubercle. It gives attachment by its prominent borders to the interspinous ligaments and by its free extremity to the supraspinous ligament. It serves mainly as a process for muscular attachment.
The transverse processes [processus transversus] are two in number and extend laterally from the arch at the junction of the pedicles and laminse. They are long, thick, backwardly directed columns of bone terminating in a clubbed extremity, on each of which is a costal pit for articulation with the tubercle of a rib. The transverse processes, in addition to supporting the ribs, afford powerful leverage to muscles.
The articular processes, two superior and two inferior, project upward and downward opposite the attachments of the transverse processes. The superior are flat and bear facets or surfaces [facies articulares superiores] which are directed
Transverse process
upward, backward, and laterally, and are situated a little in advance of the inferior, the facets of which [facies articulares inferiores] are oval, concave, and directed downward, forward, and medially.
The vertebral foramen is bounded anteriorly by the body, posteriorly and on each side by the arch. It is nearly circular, and is smaller than in the cervical or the lumbar region. When the vertebrae are articulated, the series of rings constitute the spinal or vertebral canal [canalis vertebralis],^in which is lodged the spinal cord.
THE CERVICAL VERTEBRA
A typical cervical vertebra (from the third to the sixth inclusive) presents the following characteristics (fig. 35) : — The body is smaller than in other regions of the column and is of oval shape with the long axis transverse. The lateral margins of the upper surface are raised into prominent lips, so that the surface is concave from side to side; it is also sloped downward in front. The inferior surface, on the contrary, projects downward in front and is rounded off at the sides to receive the corresponding lips of the adjacent vertebra. It is concave anteroposteriorly and convex in an opposite direction.
The roots (pedicles) are directed laterally and backward and spring from the body about midway between the upper and lower borders. The superior and inferior notches are nearly equal in depth, but the inferior are usually somewhat deeper. The laminse are long, narrow, and slender. The spinous process is short and bifid at the free extremity.
Articular processes. — Both the superior and inferior articular processes are situated at the junction of the root with the lamina and they form the upper and lower extremities of a small column of bone. The articular surfaces are oblique and nearly flat, the superior looking backward and upward, and the inferior forward and downward.
The transverse process presents near its base a round costo-transverse foramen [foramen transversarium] for the transmission of the vertebral artery, vein, and a plexus of sympathetic nerves. Moreover, each process is deeply grooved above for a spinal nerve, and is bifid at its free extremity, terminating in two tubercles — anterior and posterior. The costo-transverse foramen is very characteristic of a cervical vertebra. It is bounded medially by the pedicle, posteriorly by the transverse process (which corresponds to the transverse process of a thoracic vertebra), anteriorly by the costal process (which corresponds to the rib in the thoracic region), and laterally by the costo-transverse lamella. The latter is a bar of bone joining the two processes and directed obliquely upward and forward in the upper vertebrae and horizontally in the lower. The vertebral foramen is triangular with rounded angles, and is larger than in the thoracic or lumbra vertebrae.
Peculiar cervical vertebrae. — The various cervical vertebrae possess distinguishing features, though, with the exception of the first, second, and seventh, which are so different as to necessitate separate descriptions, these are largely confined to the direction of the costo-transverse lamella, and the size and level of the anterior and posterior tubercles. In the third the anterior tubercle is higher than the posterior and the costo-transverse lamella is obhque; in the fourth the anterior tubercle is elongated vertically, so that its lower end is nearly on a level with the posterior, though the lamella still remains oblique. In the fifth and sixth they are nearly on the same level, but in the latter the anterior tubercle is markedly developed to form the carotid tubercle.
This vertebra (fig. 36) is remarkable in that it has neither body nor spinous process. It has the form of an irregular ring, and consists of two thick portions, the lateral masses, united in front and behind by bony arches. The anterior arch joins the lateral masses in front and constitutes about one-fifth of the entire circumference of the ring. On its anterior surface it presents a tubercle for the attachment of the longus colli muscle and the anterior longitudinal ligament, and on its posterior surface a circular facet [fovea dentis] for articulation with the odontoid process [dens] of the axis. The upper and lower borders serve for the attachment of ligaments uniting the atlas to the occipital bone and axis respectively.
The lateral masses are thick and strong, supporting the articular processes above and below and extending laterally into the transverse processes. The superior articular surfaces are elongated, deeply concave, and converge in front. Directed upward and mediaOy they receive the condyles of the occipital bone, and occasionally each presents two oval facets united by an isthmus. The inferior articular surfaces are circular and almost flat; they are directed downward and medially and articulate with the axis. The articular processes, like the superior articular processes of the axis, differ from those of other vertebrte in being situated in front of the places of exit of the spinal nerves.
its membranes.
The transverse processes are large and extend farther outward than those of the vertebrae immediately below. They are flattened from above downward and each is perforated by a large costo-transverse foramen; the extremity is not bifid, but, on the contrary, is broad and rough for the attachment of numerous muscles. The posterior arch unites the lateral masses behind and forms about two-fifths of the entire circumference. It presents in the rniddle line a rough elevation or tubercle representing a rudimentary spinous process. At its junction with the lateral mass on the superior surface is a deep groove, the sulcus arteriee vertebralis, which
lodges the vertebral artery and the sub-occipital (first spinal) nerve. The groove corresponds to the superior notches of other vertebrae and occasionally it is converted into a foramen by a bony arch — the ossified oblique ligament of the atlas. A similar but much shallower notch is present on the inferior surface of the posterior arch, and, with a corresponding notch on the axis, forms an intervertebral foramen for the exit of the second spinal nerve. The upper and lower surfaces of the areh afford attachment to Ugaments uniting the atlas to the occipital bone and the axis.
The epistropheus (axis) (fig. 37) is the thickest and strongest of the bones of this region, and is so named from forming a pivot on which the atlas rotates, carrying the head. It is easily recognised by the rounded dens (odontoid process) which surmounts the upper surface of the body. This process, which represents the displaced body of the atlas, is large, blunt, and tooth-Uke, and bears on its anterior surface an oval facet for articulation with the anterior arch of the atlas; posteriorly it presents a smooth groove which receives the transverse ligament. To the apex a thin narrow fibrous band (the apical dental ligament) is attached, and on each side of the apex is a rough surface for the attachment of the alar
ligaments which connect it with the occipital bone. The enlarged part of the process is sometimes termed the head, and the constricted basal part the neck. The inferior surface of the body resembles that of the succeeding vertebrae and is concave from front to back and slightly convex from side to side. Its anterior surface is marked by a median ridge separating two lateral depressions for the insertion of the longus colli.
The roots (pedicles) are stout and broad; the laminae are thick and prismatic; the spinous process is large and strong, deeply concave on its under surface, and markedly bifid; the transverse processes are small, not bifurcated and not grooved. The costo-transverse foramen is directed very obliquely upward and laterally and the costal process is larger than the transverse.
its insertion is into the second, third, and fourth vertebrae
The superior articular surfaces are oval, and directed upward and laterally for articulation with the atlas. They are remarkable in being supported partly by the body, and partly by the pedicles, and in being situated in front of the superior notches. The inferior articular surfaces are similar in form and position to those of the succeeding vertebrae.
Situated at the junction of the cervical and thoracic regions of the vertebral column, the seventh cervical vertebra (figs. 38, 39) may be described as a transitional vertebra — i. e., possessing certain features characteristic of both regions.
whence the name vertebra prominens has been applied to this bone. The transverse process is massive; the costal element of the process is very small, but, on the other hand, the posterior or vertebral part of the process is large and becoming more like the transverse process of a thoracic vertebra.
The costo-transverse foramen is the smallest of the series and may be absent. It does not, as a rule, transmit the vertebral artery, but frequently gives passage to a vein. Occasionally the costal process is segmented off and constitutes a cervical rib. The body sometimes bears on each side near the lower border a costal pit for the head of the first rib. When this is present, there is usually a well-developed cervical rib.
The cervical vertebrae exhibit great variation in regard to the extremities of their spinous processes. As a rule among Europeans, the second, third, fourth, and fifth vertebrae possess bifid spines. The sixth and seventh exhibit a tendency to bifurcate, their tips presenting two small lateral tubercles; sometimes the sixth has a bifid spine, and more rarely the seventh pre-
sents the same condition. Occasionally all the cervical spines, with the exception of the second, are non-bifid, and even in the axis the bifurcation is not extensive. In the lower races of men the cervical spines are relatively shorter and more stunted than in Europeans generally and, as a rule, are simple. The only cervical vertebra which presents a bifid spine in all races is the axis; even this may be non-bifid in the Negro, and occasionally in the European. (Owen, Turner, Cunningham.)
The laminae of the lower cervical vertebrae frequently present posteriorly distinct tubercles from which fasciculi of the muUifidus muscle arise. They are usually confined to the sixth and seventh vertebrae, but are fairly frequent on the fifth, and are occasionally seen on the fourth.
The general characters of the thoracic (or dorsal) vertebrae have already been considered. Their most distinguishing features are the pits on the transverse processes and sides of the bodies for the tubercles and heads of the ribs respectively.
THE LUMBAR VERTEBRM
The first thoracic vertebra is a transitional vertebra. The body in its general conformation approaches very closely the seventh cervical, in that the greatest diameter is transverse, its upper surface is concave from side to side, and its lateral margins bear two prominent lips. On each side is an entire pit, close to the upper border, for the head of the first rib, and a very small pit (inferior costal pit) below for the head of the second rib. The spinous process is thick, strong, almost horizontal and usually more prominent than that of the seventh cervical, an important point to remember when counting the spines in the living subject. Occasionally the transverse process is perforated near the root.
pits are present, this vertebra is not exceptional.
The tenth usually has an entire costal pit at its upper border, on each side, but occasionally only a superior costal pit. It has no lower pits and the pits on the transverse processes are usually small.
The eleventh has a large body resembling a lumbar vertebra. The pits are on the pedicles and they are complete and of large size. The transverse processes are short, show evidence of becoming broken up into three parts, and have no pits for the tubercles of the eleventh pair of ribs.
In many mammals, the spines of the anterior vertebrae are directed backward, and those of the posterior directed forward, whilst in the centre of the column there is usually one spine vertical. The latter is called the anti-clinal vertebra, and indicates the point at which the thoracic begin to assume the characters of lumbar vertebrae. In man the eleventh thoracic is the anti-cUnal vertebra.
The twelfth resembles in general characters the eleventh, but may be distinguished from it by the articular surfaces on the inferior articular processes being convex and turned laterally as in the lumbar vertebrfe. The transverse process is rudimentary and tripartite, presenting for examination three tubercles, superior, inferior, and lateral, which correspond respectively to the mammillary, accessory, and transverse processes of the lumbar vertebra. There is one complete pit on the root (pedicle) for the head of the twelfth rib.
A pecuUarity, more frequent in the thoracic and lumbar than in the cervical and sacral regions of the column, is the existence of a half-vertebra. Such specimens have a wedge-shaped half-centrum, to which are attached a lamina, a transverse, superior, and inferior articular, and half a spinous process. As a rule, a half-vertebra is ankylosed to the vertebrae above and below.
Inferior articular process
(pedicles) are strong and directed straight backward, and the lower vertebral notches are deep and large. The laminae are shorter and thicker than those of the thoracic or cervical vertebrae, and the vertebral foramen is triangular, wider than in the thoracic, but smaller than in the cervical region. The spinous process,
thick, broad, and somewhat quadrilateral, projects horizontally backward. It is thicker below than above and terminates in a rough posterior edge. The articular processes are thick and strong. The superior articular surface is concave and directed backward and medially; the inferior is convex and looks forward and laterally. The superior pair are more widely separated than the inferior pair and embrace the inferior articular processes of the vertebra above. The posterior margin of each superior articular process is surmounted by the mammillary process or tubercle (metapophysis) which corresponds to the superior tubercle of the transverse process of the last thoracic vertebra. In man. the mammillary tubercles are rudimentary, but in some animals they attain large proportions, as in the kangaroo and armadillo. The transverse processes are long, slender, somewhat spatula-shaped, compressed from before backward, and directed laterally and a little backward. They are longest in the third vertebra and diminish in the fourth, second, and fifth, in this order, to the first, in which they are shortest of all. Their extremities are in series with the lateral tubercles of the transverse processes of the twelfth thoracic vertebra and also with the ribs. With the latter the so-called transverse processes in the lumbar region are homologous, and hence they are sometimes called the costal processes. Occasionally the costal element differentiates and becomes a well-developed lumbar rib.
Costal element
Behind the base of each transverse or costal process is a small eminence, directed downward, which corresponds with the inferior tubercle of the lower thoracic transverse process, and with the transverse processes of the thoracic vertebrae above, and is named the accessory process (anapophysis). The accessory process represents the tip of the partially suppressed true transverse process of a lumbar vertebra. It is well developed in some of the lower animals, as in the dog and cat.
Each of the five lumbar vertebrae is readily recognized. The body of the first is deeper behind than in front; the body of the second is equal in depth in front and behind; the bodies of the third, fourth, and fifth are deeper in front than behind, but the third has long transverse processes and the inferior articular processes are not widely separated. The fourth has shorter transverse processes and the inferior articular processes are placed more widely apart. The fifth lumbar vertebra deviates in some of its features so widely from the other members of the series that special prominence must now be given them.
THE SACRUM
than behind in consequence of being bevelled off to form with the sacrum the sacrovertebral angle. The transverse processes are short, thick, conical, and spring from the body as well as from the roots of the arch. They are very strong for the attachment of the ilio-lumbar ligaments. The spinous process is smaller than that of any of the other lumbar vertebrse; the laminae project into the vertebral foramen on each side; and the roots are stout and flattened from above downward. The inferior articular processes are separated to such a degree as to be wider apart than the superior, and they articulate with the first sacral vertebra.
The roots of the arch in this vertebra are liable to a remarkable deviation from the conditions found in other parts of the spine. The peculiarity consists of a complete solution in the continuity of the arch immediately behind the superior articular processes. In such specimens the anterior part consists of the body carrying the roots, transverse and superior articular processes; whilst the posterior segment is composed of the laminae, spine, and inferior articular processes. The posterior segment of the ring of this vertebra may even consist of two pieces. There is reason to believe that this abnormality of the fifth lumbar vertebra occurs in five per cent, of aU subjects examined. Sir William Turner, in his report on the human skeletons in the Challenger Reports, found seven examples among thirty skeletons examined. The skeletons in which this occurred were: — a Malay, an Andamanese, a Chinese, two Bushmen, an Eskimo, and a Negro. Turner has also seen it in the skeleton of a Sandwich Islander. A similar condition is occasionally met with either unilaterally or bilaterally in the thoracic vertebrae.
The five sacral vertebrse (figs. 43, 44) are united in the adult to form the os sacrum, a large, curved, triangular bone, firmly wedged between the innominate bones, and completing, together with the coccyx, the posterior boundary of the
minor (or small) pelvis. Of the five vertebrae which compose the sacrum the uppermost is the largest, the succeeding ones become rapidly smaller, and the fifth is quite rudimentary. In the erect posture the sacrum lies obliquely, being directed from above downward and backward, and forms with the last lumbar vertebra an anterior projection known as the promontory. The sacrum presents for examination a pelvic and a dorsal surface, two lateral margins, a base, and an apex.
middle by four transverse ridges [lineae transversee] which represent the ossified intervertebral discs and separate the bodies of the five sacral vertebrae. Of the bodies, the first and second are nearly equal in size and are larger than the third, fourth, and fifth, which, in vertical depth, are also nearly equal to each other. At the extremities of the transverse ridges on each side are four openings, called the anterior sacral foramina, which correspond to the intervertebral foramina in other regions of the column, and transmit the anterior divisions of the first four sacral nerves ; they are also traversed by branches of the lateral sacral arteries. The foramina are separated by wide processes, representing the costal processes of the vertebrae, which unite laterally to form the lateral portion (or mass) [pars lateralis]. The latter is grooved for the sacral nerves, and rough opposite the second, third, and fourth sacral vertebrae, for the origin of the piriformis muscle. The lateral part of the fifth sacral vertebra gives insertion to fibres of the coccygeus.
. The dorsal surface is strongly convex and rough. The middle line is occupied by four eminences representing the somewhat suppressed spinous processes. Of these the first is the largest, the second and third may be confluent, and the fourth is often absent. The processes are united to form an irregular ridge or
Notch for fifth sacral
crest [crista sacralis media]. The bone on each side of the spines is slightly hollowed and is formed by the united laminae. In the fourth sometimes, but always in the fifth, the laminae fail to meet in the middle line, leaving a gap [hiatus sacralis] at the termination of the spinal canal, the lateral margins of which are prolonged downward as the sacral cornua. They represent the lower articular processes of the fifth sacral vertebra and give attachment to the posterior sacrococcygeal ligaments. Lateral to the laminae is a second series of small eminences which represent the articular and mammillary processes of the vertebrae above. The first pair are large for the last lumbar vertebra, the second and third are small, and the fourth and fifth are inconspicuous. Together they form a pair of irregular ridges [cristae sacrales articulares].
Immediately lateral to the articular processes are the posterior sacral foramina, four on each side; they are smaller than the anterior, and give exit to the posterior primary divisions of the first four sacral nerves. Lateral to the fora^ mina on each side are five elevations representing the transverse processes. The first pair, situated at the junction of the posterior surface with the base, are large and conspicuous, and serve all for the attachment of ligaments and muscles.
Together they form on each side of the sacrum an irregular ridge [crista saoralis lateralis]. The space between the spinous and transverse processes presents a shallow concavity known as the sacral groove, continuous above with the vertebral groove of the movable part of the column, and, like it, lodging the multifidus muscle. Bridging across the groove and attached to the sacral spines medially, and to the lower and back part of the sacrum laterally, is the flat tendon of origin of the sacro-spinalis {erector spince) . The gluteus maximus takes origin from the back of the lower two pieces of the sacrum.
The base or upper surface of the sacrum bears considerable resemblance to the upper surface of the fifth lumbar vertebra. It presents in the middle the body, of a reniform shape, posterior to which is the upper end of the sacral canal bounded by two laminae. On each side of the canal are two articular processes bearing;wellmarked mammillary tubercles. The conjoined transverse and costal processes form on each side a broad surface, the wing or ala of the sacrum, continuous with the iliac fossa of the hip bone, and giving attachment to a few fibres of the iliacus.
The lateral margins. — It has already been noted that the lateral portion of the sacrum is the part lateral to the foramina. It is broad and thick above, where it forms the ala, but narrowed below. The lateral aspect of the upper part presents in front a broad irregular surface, covered in the recent state with fibro-cartilage, which articulates with the ilium and is known as the auricular surface. It is bounded posteriorly by some rough depressions for the attachment of the posterior sacro-iliac ligaments. Below the auricular surface, the lateral margin is rough for the sacro-tuberous (greater) and sacro-spinous (lesser sacrosciatic) ligaments, and terminates in the projection known as the inferior lateral angle. Immediately below the angle is a notch, converted into a foramen by the transverse process of the first coccygeal vertebra, and a ligament connecting this with the inferior lateral angle of the sacrum. Through this foramen passes" the anterior branch of the fifth sacral nerve.
life the apex of the sacrum becomes united to the coccyx by bone.
The sacral canal is the continuation of the spinal canal through the sacrum. Like the bone, it is curved and triangular in form at the base and flattened toward the apex. It terminates at the hiatus sacralis between the sacral cornua, where the laminse of the fourth and fifth sacral vertebrae are incomplete. The canal opens on the surface by the anterior and posterior sacral foramina and lodges the lower branches of the cauda equina, the filum terminale, and the lower extremity of the dura and arachnoid. The sub-dural and sub-arachnoid spaces extend downward within the canal as far as the body of the third sacral vertebra.
Differences in the two sexes. — The sacrum of the female is usually broader in proportion to its length, much less curved, and directed more obliquely backward than in the male. The curvature of the female sacrum belongs chiefly to the lower part of the bone, whereas in the male it is equally distributed over its whole length; but the curvature is subject to considerable variation in different skeletons.
Sacral canal
Racial differences. — The human sacrum is characterised by its great breadth in comparison with its length, though in the lower races it is relatively longer than in the higher. The proportion is expressed by the sacral index = . — — rr ' The average sacral index in the British
The four coccygeal vertebrae are united in the adult to form the coccyx [os coccygis] (fig. 47). While four is the usual number of these rudimentary vertebrse, occasionally there are five, and rarely three. In middle life the first piece is usually separate, and the original division of the remaining portion of the coccyx
joined to the sacrum.
The first piece of the coccyx is much broader than the others. It consists of a body, transverse processes, and rudiments of a neural arch. The body presents on its upper surface an oval facet for articulation with the apex of the sacrum. On each side of the body a transverse process projects laterally and is joined either by ligament or bone to the inferior lateral angle of the sacrum, forming a foramen for the anterior division of the fifth sacral nerve. From the posterior surface of the body two long coccygeal cornua project upward and are connected to the sacral cornua by the posterior saero-coccygeal ligaments, enclosing on each side an aperture — the last intervertebral foramen — for the exit of the fifth sacral nerve. The coccygeal cornua represent the roots and superior articular processes of the first coccygeal vertebra.
The second piece of the coccyx is much smaller than the first, and consists of a body, traces of transverse processes, and a neural arch, in the form of slight tubercles at the sides and on the posterior aspect of the body.
The vertebral column (fig. 48) is the central axis of the skeleton and is situated in the median line at the posterior aspect of the trunk. Superiorly it supports the skull; laterally it gives attachment to the ribs, through which it receives the weight of the upper limbs, and inferiorly it is supported by the hip bones, by which the weight of the trunk is transmitted to the lower limbs. Its length varies in different skeletons, but on an average it measures about 70 cm. (28 in.) in the male and about 2.5 cm. (1 in.) less in the female. To the entire length the cervical region contributes 12.5 cm. (5 in.), the thoracic 27.5 cm. (11 in.), the lumbar 17.5 cm. (7 in.), and the sacro-coccygeal portion the remaining 12.5 cm. (5 in.). The vertebral column presents a series of curvatures, four when viewed in profile and one when viewed from the front or back. The former are directed alternately forward and backward, and are named, from the regions of the column in which they occur, cervical, thoracic, lumbar, and sacral. The fifth curve is lateral, being in most cases directed toward the right side.
The cervical, thoracic and lumbar curvatures pass imperceptibly into one another, but at the junction of the last lumbar vertebra with the sacrum a well-marked angle occurs, known as the sacro-vertebral or lumbo-sacral angle, with the result that the promontory of the sacrum overhangs the cavity of the minor (small) pelvis and forms a portion of the superior aperture of the small pelvis.
The thoracic and sacral curves have their concavities directed forward and are developed during intra-uterine life. They are in obvious relation to two great cavities of the trunk, thoracic and pelvic, and may be regarded as primary or accommodation curves, for the thoracic and pelvic viscera. The thoracic curve extends from the second to the twelfth thoracic vertebra and the sacral curve coincides with the sacrum and coccyx.
The cervical and lumbar curves have their convexities directed forward, and are developed during the first year after birth. They are essentially curves of compensation, necessary for the maintenance of the upright posture, and are brought about by modifications in the shape of the intervertebral discs. The cervical curve is formed about the third month, or as soon as the infant can sit upright. The great pecuharity of the curve is that it is never consolidated, being present when the body is placed in the erect position and obliterated by bending the head down upon the chest. The lumbar curve is developed about the end of the first year or when the child begins to walk, but is not consolidated until adult life. (Symington.) The cervical curve extends from the atlas to the second thoracic vertebra, and the lumbar curve from the twelfth thoracic to the promontory of the sacrum.
The lateral curve is situated in the upper thoracic region, and when directed to the right is probably associated with the greater use made of the right hand. This curve, however, is particularly liable to modification in different occupations and in different races.
Viewed from the front, the vertebral column presents a series of pyramids due to the successive increase and decrease in size of the bodies. These become broader from the axis to the first thoracic vertebra and then decrease to the fourth thoracic. The first pyramid therefore includes all the cervical vertebrae except the atlas, and has the apex directed upward and its base downward, whilst the second is inverted and formed by the first four thoracic vertebrae. The third pyramid, much the longest, is the result of the increase in size from the fourth thoracic to the fifth lumbar vertebra, and the fourth, which is inverted, is produced by the rapid contrae- ■ tion of the sacral and coccygeal vertebriE.
Viewed from behind, the spinous processes project in the middle Hne, and the transverse processes as two lateral rows. Of the spines, those of the axis, seventh cervical, first thoracic, and the lumbar vertebrae appear most prominent. On each side is the vertebral groove, the floor of which is formed in the cervical and lumbar regions by the laminae and articular processes,
OSSIFICATION OF VERTEBRA
and in the thoracic region, by the laminae and transverse processes. The transverse processes project laterally for a considerable distance in the atlas, first thoracic, and the middle of the lumbar series; they are shortest in the third cervical and the twelfth thoracic.
the fibres of the cancellous tissue are seen to be arranged vertically and horizontally, the vertical fibres being curved with their concavities directed toward the centre of the bone. The horizontal fibres are slightly curved parallel with the upper and lower surfaces, and have their convexities toward the centre of the bone. They are not so well defined as the vertical set. (Wagstaffe.)
appear, one in the^body and two in the arch, about the seventh week of intra-uterine life. In the thoracic region the nucleus for the body appears first, but in the cervical region it is preceded by the centres for the arch. The nucleus for the body soon becomes bilobed, and this condition is sometimes so pronounced as to give rise to the appearance of two distinct nuclei. Indeed, the nucleus is very rarely double and the two parts of the body may remain separate throughout life (fig. 49). The bilateral character of the nucleus is further emphasised by the occasional formation of half-vertebrje. The lateral centres are deposited near the bases of the
parts of the tran8.verse and spinous processes.
At birth a typical vertebra consists of three osseous pieces — a body and two lateral masses, which constitute the arch, the parts being joined together by hyahne cartilage. The line of union of the lateral portion with the body is known as the neuro-ceniral suture, and is not actually obliterated for several years after birth. In the thoracic region the central ossification does not pass beyond the point with which the head of the rib articulates, and leaves a portion of the bodj' on each side formed from the lateral ossification. A thoracic vertebra at the fifth year shows
that the pits for the heads of the ribs are situated behind the neuro-central suture, which is directed obhquely backward and medially. The laminae unite during the first year after birth; and by the gradual extension of ossification into the various processes, the vertebrae have attained almost their full size by the time of puberty. Subsequently the secondary centres appear in the cartilaginous extremities of the spinous and transverse processes, and in the carti-
THE Body.
lage on the upper and lower surfaces of the bodies, forming in each vertebra two annular plates, thickest at the circumference and gradually thinning toward the central deficiency. The epiphyses appear from the fifteenth to the twentieth year and join with the vertebra by the twenty-fifth year.
The anterior arch is ossified from one centre, which, however, does not appear until a few months after birth. Union of the lateral parts occurs posteriorly in the third year, being sometimes preceded by the appearance of a secondary centre of ossification in the intervening cartilage, and the union of the lateral parts with the anterior arch occurs about the sixth year.
EPISTROPHEUS
Epistropheus. — The arch, and the processes associated with it, are formed from two lateral centres which appear, like those in the other vertebras, about the seventh week. The common piece of cartilage which precedes the body and dens is ossified from four (or five) centres, one (or two) for the body of the axis, in the fourth month, two, laterally disposed, for the dens, a
few weeks later, and one, for the apex of the dens, in the second year. The two collateral centres for the main part of the dens soon coalesce, so that at birth the axis consists of four osseous pieces — two lateral portions which constitute the arch, the body, and the dens, surmounted by a piece of cartilage. During the third or fourth year the dens joins with the body, the line of
Epiphysial plate
union being indicated even in advanced life by a small disc of cartilage, and the arch unites in front and behind about the same time or a little later. The apical nucleus of the dens, which represents an epiphysis, joins the main part about the twelfth year and in the seventeenth year
Cartilage representing the intervertebral disc between the dens and the body of the epistropheus
ittal direction. The sixth, seventh, and even the fifth have additional centres which appear before birth for the anterior or costal divisions of the transverse processes. In the other cervical vertebrae the costal processes are ossified by extension of the lateral nuclei. The costal processes of the seventh cervical sometimes remain separate, constituting cervical ribs.
Lumbar vertebrae. — In the lumbar vertebrEe the neuro-oentral suture is almost transverse, and to the usual number of centres of ossification, two other epiphyses for the mammillary tubercles are added, the centres appearing about puberty. The transverse process of the first lumbar vertebra is occasionally developed from an independent centre.
rior articular process, and another on each side for the lamina, inferior articular process, and the lateral half of the spinous process (fig. 60). There may be failure of union of roots with the laminae or of the laminae with one another.
Sacral vertebree. — The sacrum ossifies from thirty-five centres, which may be classified as follows ; — In each of the five vertebrae there are three primary nuclei — one for the body and two for the arch; in each of the first three the costal element of the lateral mass on each side is
Ossific centre in the body of first sacral vertebra. Beneath this are seen in succession the centres in the bodies of the second, third, fourth, and fifth vertebras
COCCYGEAL VERTEBRA
Consolidation begins soon after puberty by fusion of the costal processes, and this is followed by ossification from below upward in the intervertebral discs, resulting in the union of the adjacent bodies and the epiphysial plates, the ossific union of the first and second being completed by the twenty-fifth year or a little later. The marginal epiphyses are also united to the
more central parts of the bone and can be well seen in sections.
Coccygeal vertebrae. — The coccygeal vertebrae are cartilaginous at birth and each is usually ossified from a single centre, though there may be two for the first piece. Ossification begins soon after birth in the first segment, and in the second from the fifth to the tenth year.
The centres for the third and fourth segments appear just before, and after, puberty respectively. As age advances the various pieces become united with each other, the three lower uniting before middle life and the upper somewhat later. In advanced life the coccyx maj' join with the sacrum, the union occurring earUer and more frequently in the male than in the female.
The Serial Morphology of the Vertebrae
Although at first sight many of the vertebrae exhibit peculiarities, nevertheless a study of the mode by which they develop, and their variations, indicates the aerial homology of> the constituent parts of the vertebrae in each region of the column.
The body (centrum) of the vertebra is that part which immediately surrounds the notochord. This part is present in all the vertebrae of man, but the centrum of the atlas is dissociated from its arch, and ankylosed to the body of the epistropheus. The reasons for regard-
Costal process
ing the dens as the body of the atlas are these: In the embryo the notochord passes through it on its way to the base of the cranium. Between the dens and the body of the axis there is a swelling of the notochord in the early embryo as in other intervertebral regions. This swelling is later indicated by a small intervertebral disc hidden in the bone, but persistent even in old age. Moreover, the dens ossifies from primary centres, and in chelonians it remains as a separate ossicle throughout life; in Ornithorhynchus it remains distinct for a long time, and it has been found separate even in an adult man. Lastly, in man and many mammals, an epi-
BONES OF THE SKULL 51
physial plate develops between it and the body of the axis. The anterior arch of the atlas represents a cartilaginous hypochordal bar, which is present in the early stages of development of the vertebrae, but disappears in all but the atlas in the ossification of the body.
consideration here.
•The transverse processes offer more difficulty. They occur in the simplest form in the thoracic series. Here they articulate with the tubercles of the ribs, whence the term tubercular processes or diapophyses has been given them (the place of articulation of the head of the rib with the vertebra is the capitular process or parapophysis), and the transverse process and the neck of the rib enclose an arterial foramen named the costo-transverse foramen. In the cervical region the costal element (pleur apophysis) and the transverse process are fused together, and the conjoint proce.ss thus formed is pierced by the costo-transverse foramen. The compound nature of the process is indicated by the fact that the anterior or costal processes in the lower cervical vertebrte arise from additional centres and occasionally retain their independence as cervical ribs, and in Sauropsida (birds and reptiles) these processes are represented by free ribs. In the lumbar region, the compound nature of the transverse process is further marked. The true transverse process is greatly suppressed, and its extremity is indicated by the accessory tubercle. Anterior to this in the adult vertebrae a group of holes represents the costo-transverse foramen, and the portion in front of this is the costal element. Occasionally it persists as an independent ossicle, the lumbar rib.
In the sacral series the costal elements are coalesced in the first three vertebrae to form the greater portion of the lateral portion for articulation with the ilium, the costo-transverse foramina being completely obscured. In rare instances the first sacral vertebra will articulate with the ilium on one side, but remain free on the other, and under such conditions the free process exactly resembles the elongated transverse process of a lumbar vertebra. The first three sacral vertebrae which develop costal processes for articulation with the ilium are termed true sacral vertebrae, while the fourth and fifth are termed pseudo-sacral. A glance at fig. 64 will show the homology of the various parts of a vertebra from the cervical, thoracic, lumbar, and sacral regions.
The skull is the expanded upper portion of the axial skeleton and is supported on the summit of the vertebral column. It consists of the cranium, a strong bony case enclosing the brain and made up of eight bones — viz., occipital, tvs^o parietal, frontal, two temporal, sphenoid, ethmoid; and the bones of the face, surrounding the mouth and nose, and forming with the cranium the orbital cavity for the reception of the eye. The bones of the face are fourteen in number — viz., two maxillae, two zygomatic {malar), two nasal, two lacrimal, two palate, two inferior conchoe {turbinates), the mandible, and the vomer. All the bones enumerated above, with the exception of the mandible, are united by suture and are therefore immovable. The proportion between the facial and cranial parts of the skull varies at different periods of life, being in the adult about one (facial) to two (cranial), and in' the new-born infant about one to eight. A group of movable bones, comprising the hyoid, suspended from the basilar surface of the cranium, and three small bones, the incus, malleus, and stapes, situated in the middle ear or tympanic cavity, is also included in the enumeration of the bones of the skull.
According to the BNA nomenclature, the term cranium is used in a wider sense as synonymous with skull, and is subdivided into cranium cerebrate (cranium in the narrower sense) and cranium viscerate (facial skeleton). In the BNA, seven bones above listed with the facial, — two inferior conchae, two lacrimal, two nasal and the vomer — are classed with the cranium cerebrate.
THE OCCIPITAL
The occipital bone [os occipitale] (fig. 65) is situated at the posterior and inferior part of the cranium. In general form it is flattened and trapezoid in shape, curved upon itself so that one surface is convex and directed backward and somewhat downward, while the other is concave and looks in the opposite direction. It is pierced in its lower and front part by a large aperture, the foramen magnum, by which the vertebral canal communicates with the cavity of the cranium.
The occipital bone is divisible into four parts, basilar, squamous, and two condylar, so arranged around the foramen magnum that the basilar part lies in front, the condylar parts on either side, and the squamous part above and behind.
Speaking generally, this division corresponds to the four separate parts of which the bone consists at the time of birth (fig. 69), known as the basi-occipital, supra-occipital, and exoccipital. In early life these parts fuse together, the lines of junction of the supra-occipital and ex-occipitals extending lateralward from the posterior margin of the foramen magnum, and those of the ex-occipitals and basi-occipital passing through the condyles near their anterior extremities. It must be noted, however, that the upper portion of the squamous part represents an additional bone, the interparietal.
The squamous part [squama occipitalis] (supra-occipital and interparietal) presents on its convex posterior surface, and midway between the superior angle and the posterior margin of the foramen magnum, a prominent tubercle known as the external occipital protuberance, from which a vertical ridge — the external occipital crest — runs downward and forward as far as the foramen. The protuberance and crest give attachment to the ligamentum nuchse.
pharynx to pharyngeal tubercle
Arching lateralward on each side from the external occipital protuberance toward the lateral angle of the bone is a semicircular ridge, the superior nuchal line [linea nuchce superior], which divides the surface into two parts — an upper [planum occipitale] and a lower [planum nuchale]. Above this line, a second less distinctly marked ridge — the highest nuchal line [linea nuchse suprema] — is usually seen. It is the most curved of the three lines on this surface and gives attachment to the epicranial aproneuosis and to a few fibres of the occipitalis muscle. Between the superior and highest curved lines is a narrow crescentic area in which the bone is smoother and denser than the rest of the surface, whilst the part of the bone above the hnea suprema is convex and covered by the scalp.
The lower part of the surface is ver.y uneven and subdivided into an upper and a lower area by the inferior nuchal line, which runs laterally from the middle of the crest to the jugular process.
The curved lines and the areas thus mapped out between and below them give attachment to several muscles. To the superior nuchal line are attached, medially the trapezius, and laterally the occipitalis and sterno-cleido-mastoid; the area between the superior and inferior curved lines receives the semispinalis capitis (complexus) medially, and splenius capitis and ohliquus capitis superior laterally; the inferior nuchal line and the area below it afford insertion to the rectus capitis posterior minor and major.
The anterior or cerebral surface is deeply concave and marked by two grooved ridges which cross one another and divide the surface into four fossse of which the two upper, triangular in form, lodge the occipital lobes of the cerebrum, and the two lower, more quadrilateral in outline, the lobes of the cerebellum. The vertical ridge extends from the superior angle to the foramen magnum and the transverse ridge from one lateral angle to the other, the point of intersection being indicated by the internal occipital protuberance [eminentia cruciata]. The
upper part of the vertical ridge is grooved [sulcus sagittalis] for the superior sagittal {longitudinal) sinus and gives attachment, by its margins, to the falx cerebri; the lower part is sharp and known as the internal occipital crest, and affords attachment to the falx cerebelli. Approaching the foramen magnum the ridge divides, and the two parts become lost upon its margin. The angle of divergence sometimes presents a shallow fossa for the extremity of the vermis of the cerebellum, and is called the vermiform fossa. The two parts of the transverse ridge are deeply grooved [sulcus transversus] for the transverse {lateral) sinuses, and the margins of the groove give attachment to the tentorium cerebelli. To one side of the internal occipital protuberance is a wide space, where the vertical groove is continued into one of the lateral grooves (more frequently the right), and this is termed the torcular Herophili; it is sometimes exactly in the middle line.
The squamous portion has three angles and four borders. The superior angle forming the summit of the bone is received into the space formed by the union of the two parietals. The lateral angles are ver}' obtuse and correspond in situatio n with the lateral ends of the transverse ridges. Above the lateral angle on each side the margin is deeply serrated, forming the lambdoid or superior border which extends to the superior angle and articulates with the posterior border of the parietal in the lambdoid suture. The mastoid or inferior border extends
portion of the temporal.
The condylar or lateral portions [partes laterales] (ex-occipitals) form the lateral boundaries of the foramen magnum and bear the condyles on their inferior surfaces. The condyles are two convex oval processes of bone with smooth articular surfaces, covered with cartilage in the recent state, for the superior articular processes of the atlas. They converge in front, and are somewhat everted. Their margins give attachment to the capsular ligaments of the occipito-atlantal joints and on the medial side of each is a prominent tubercle for the alar (lateral odontoid) ligament. The anterior extremities of the condyles extend beyond the ex-occipitals on the basi-occipital portion of the bone. The hypoglossal (anterior condyloid) foramen or canal [canalis hypoglossi] perforates the bone at the base of the condyle, and is directed from the interior of the cranium, just above the foramen magnum, forward and laterally; it transmits the hypoglossal nerve and a twig of the ascending pharyngeal artery.
The foramen is sometimes double, being divided by a delicate spicule of bone. Above the canal is a smooth convexity known as the tuberculum jugulare sometimes marked by an oblique groove for the ninth, tenth and eleventh cranial nerves. Posterior to each condyle is a pit, the
Hypoglossal foramen.
condylar fossa, which receives the hinder edge of the superior articular process of the atlas when the head is extended. The floor of the depression is occasionally perforated by the condylar (posterior condyloid) canal or foramen [canalis condyloideus], which transmits a vein from the transverse sinus. Projecting laterally opposite the condyle is a quadi'ilateral portion of bone known as the jugular process, the extremity of which is rough for articulation with the jugular facet on the petrous portion of the temporal bone. Up to twenty-five years the bones are united here by means of cartilage; about this age ossification of the cartilage takes place, and the jugular process thus becomes fused with the petrosal. Its anterior border is deeply notched to form the posterior boundary of the jugular foramen, and the notch is directly continuous with a groove on the upper surface which lodges the termination of the transverse sinus. In or near the groove is seen the inner opening of the condylar foramen. The lower surface of the process gives attachment to the rectus capitis lateralis and the oblique occipito-atlantal ligament. Occasionally the mastoid air cells extend into this process and rarely a process of bone, representing the paramastoid process of many mammals, projects downward from its under aspect and may be so long as to join or articulate with the transverse process of the atlas.
The basilar portion (basi-occipital) is a quadrilateral plate of bone projecting forward and upward in front of the foramen magnum. Its superior surface presents a deep groove — the basilar groove [chvus]; it supports the medulla oblongata and gives attachment to the tectorial membrane (occipito-axial ligament). The lower surface presents in the middle line a small elevation known as the pharyngeal tubercle for the attachment of the fibrous raphe of the pharynx, and immediately in front of the tubercle there is frequently a shallow
nearer to the condyle, and near the foramen magnum this surface gives attachment to the anterior occipito-atlantal ligament. Anteriorly the basilar process articulates by synchondrosis with the body of the sphenoid up to twenty years of age, after which there is complete bony union. Posteriorly it presents a smooth rounded border forming the anterior boundary of the foramen magnum. It gives attachment to the apical odontoid ligament, and above this
to the ascending portion of the crucial ligament. In the occipital bone at the sixth year the lateral extremities of this border are enlarged to form the basilar portion of the condyles. The lateral borders are rough below for articulation with the petrous portion of the temporal bones, but above, on either side of the basilar groove, is a half-groove, which, with a similar half -groove on the petrous portion of the temporal bone, lodges the inferior petrosal sinus.
The foramen magnum is oval in shape, with its long axis in a sagittal direction. It transmits the medulla oblongata and its membranes, the accessory nerves (spinal portions) , the vertebral arteries, the anterior and posterior spinal
arteries, and the tectorial membrane (occipito-axial ligament). It is widest behind, where it transmits the medulla, and is narrower in front, where it is encroached upon by the condyles.
Occasionally a facet is present on the anterior margin, forming a third occipital condyle for articulation with the dens. Between the condyles and behind the margin of the foramen magnum the posterior occipito-atlantal ligament obtains attachment.
auricular, middle meningeal, vertebral and the ascending pharyngeal arteries.
Articulations. — The occipital bone is connected by suture with the two parietals, the two temporals, and the sphenoid; the condyles articulate with the atlas, and exceptionally the occipital articulates with the dens of the epistropheus by means of the third occipital condyle.
THE PARIETAL BONE 57
Ossification. — The occipital bone develops in four pieces. The squamous portion is ossified from four centres, arranged in two pairs, which appear about the eighth week. The upper pair are deposited m membrane, and this part of the squamous portion represents the interparietal bone of many animals. The lower oair, deposited in cartilage, form the true supra-ocoipital element, and the four parts quickly coalesce near the situation of the future occipital protuberance. For many weeks two deep lateral fissures separate the interparietal and supraoccipital portions, and a membranous space extending from the centre of the squamous portion to the foramen magnum partially separates the lateral portions of the supra-occipital. This space is occupied later by a spicule of bone, and is of interest as being the opening through which the form of hernia of the brain and its rneninges, known as occipital meningocele or encephalocele, occurs. The basi-occipital and the two ex-occipitals are ossified each from a single nucleus which appears in cartilage from the eighth to the tenth week.
At birth the Ijone consists of four parts united by strips of cartilage, and in the squamous portion fissures running in from the upper and lateral angles are still noticeable. The osseous union of the squamous and ex-occipital is completed in the fifth year, and that of the exoccipitals with the basi-occipital before the seventh year. Up to the twentieth year the basioccipital is united to the body of the sphenoid by an intervening piece of cartilage, but about that date ossific union begins and is completed in the course of two or three years. Occasionally the interparietal portion remains separate throughout Ufe (fig. 70), forming what has been termed the inca hone, or it may be represented by numerous detached ossicles or Wormian bones. In some cases a large Wormian bone, named the pre-interparietal, is found, partly replacing the interparietal bone (fig. 71). A pre-interparietal bone is found in some mammals, and it has occasionally been observed in the human foetal skull. In fig. 71 the bone is seen in an adult human skull — a distinctly rare condition. I
The two parietal bones (figs. 72, 73), interposed between the frontal before and the occipital behind, form a large portion of the roof and sides of the cranium. Each parietal bone [os parietale] is quadrilateral in form, convex externally, concave internally, and each presents for examination two surfaces, four borders, and four angles.
The parietal surface is smooth and is crossed, just below the middle, by two curved lines known as the temporal lines. The superior line gives attachment to the temporal fascia; the lower, frequently the better marked, limits the origin of the temporal muscle; whilst the narrow part of the surface enclosed between them is smooth and more poHshed than the rest. Immediately above the ridges is the most convex part of the bone, termed the parietal eminence [tuber parietale], best marked in young bones, and indicating the point where ossification commenced. Of the two divisions on the parietal surface marked off by the temporal lines, the upper is covered by the scalp, and the lower, somewhat striated, ait'ords attachment to the temporal muscle. Close to the upper border and near to the occipital angle is a small opening — the parietal foramen — which transmits a vein to the superior sagittal {longitudinal) sinus.
The cerebral surface is marked with depressions corresponding to the cerebral convolutions and by numerous deep furrows, running upward and backward from the sphenoidal angle and the lower border, for the middle meningeal vessels (sinus and artery). A shallow depression running close to the superior border forms, with the one of the opposite side, a channel for the superior sagittal sinus, at the side of which are small irregular pits for the Pacchionian bodies; the pits are usually present in adult skulls, but are best marked in those of old persons. The margins of the groove for the superior sagittal sinus give attachment to the falx cerebri.
Borders. — The sagittal or superior border, the longest and thickest, is deeply serrated to articulate with the opposite parietal, with which it forms the sagittal suture. The frontal or anterior border articulates with the frontal to form the coronal suture. It is deeply serrated and bevelled, so that it is overlapped by the frontal above, but overlaps the edge of that bone below. The occipital or posterior border articulates with the occipital to form the lambdoid suture, and resembles the superior and anterior in being markedly serrated. The squamosal or inferior border is divided into three portions : — the anterior, thin and bevelled, is overlapped by the tip of the great wing of the sphenoid; the middle portion, arched and also bevelled, is overlapped by the squamous part of the tempora,l; and the posterior portion, thick and serrated, articulates with the mastoid portion of the temporal bone.
fontanelle. The sphenoidal or anterior inferior angle is thin and prolonged downward to articulate with the tip of the great wing of the sphenoid. Its inner surface is marked by a deep groove, sometimes converted into a canal for a short
Grooves for middle meningeal artery
distance, for the middle meningeal vessels (chiefly for the sinus). The occipital or posterior superior angle is obtuse and occupies that part which during foetal life enters into formation of the posterior fontanelle. The mastoid or posterior
Articulations. — The parietal articulates with the occipital, frontal, sphenoid, temporal, its fellow of the opposite side, and the epipterio bone when present. Occasionally the temporal and epipteric bones exclude the parietal from articulation with the great wing of the sphenoid.
Ossification. — The parietal ossifies from a single nucleus which appears in the outer layer of the membranous wall of the skull about the seventh week. The ossification radiates in such a way as to leave a cleft at the upper part of the bone in front of the occipital angle, the
cleft of the two side forming a lozenge-shaped space across the sagittal suture known as the sagittal fontanelle. This is usually closed about the fifth month of intra-uterine life, but traces may sometimes be recognised at the time of birth, and the parietal foramina are to be regarded as remains of the cleft. According to Dr. A. W. W. Lea, a well-developed sagittal fontanelle is present in 4 . 4 per cent, of infants at birth. In such cases it closes within the first two months of life, but at times it may remain open for at least eight months after birth and possibly longer. Rarely the parietal bone is composed of two pieces (fig. 74), one above the other, and separated by an antero-posterior suture (sub-sagittal suture), more or less parallel with the sagittal suture. In such cases the parietal is ossified from two centres of ossification.
THE FRONTAL
The frontal bone [os frontale] closes the cranium in front and is situated above the skeleton of the face. It consists of two portions — a frontal {vertical) portion [squama frontalis], forming the convexity of the forehead, and an orbital {horizontal) portion, which enters into formation of the roof of each orbit.
Frontal {vertical) portion. — The frontal surface is smooth and convex, and usually presents in the middle line above the root of the nose some traces of the suture which in young subjects traverses the bone from the upper to the lower part. This suture, known as the frontal or metopic suture, indicates the line of junction of the two lateral halves of which the bone consists at the time of birth; in the adult the suture is usually obliterated except at its lowest part. On each side is a rounded elevation, the frontal eminence [tuber frontale], very prominent in young bones, below which is a shallow groove, the sulcus transversus, separating the frontal eminence from the superciliary arch. The latter forms an arched pi^ojection above the margin of the orbit and corresponds to an air-cavity within the bone known as the frontal sinus; it gives attachment to the orbicularis oculi and the corrugator muscles. The ridges of the two sides converge toward the
median line, but are separated by a smooth surface called the glabella (nasal eminence). Below the arch the bone presents a sharp curved margin, the supraorbital border, forming the upper boundary of the circumference of the orbit and separating the frontal from the orbital portion of the bone. At the junction of its medial and intermediate third is a notch, sometimes converted into a foramen, and known as the supra-orbital notch or foramen ; it transmits the supra-orbital nerve, artery, and vein, and at the bottom of the notch is a small opening for a vein of the diploe which terminates in the supra-orbital. Sometimes, a second less marked notch is present, medial to the supra-orbital, and known as the frontal notch; it transmits one of the divisions of the supra-orbital nerve. The extremities of the supra-orbital border are directed downward and form the medial and zygomatic (lateral angular) processes. The prominent zygomatic process articulates with the zygomatic bone and receives superiorly two well-marked lines which converge somewhat as they curve downward and forward across the bone. These are the superior and inferior temporal lines, continuous with the
Zygomatic process
temporal lines on the parietal bone, the upper giving attachment to the temporal fascia and the lower to the temporal muscle. Behind the lines is a slight concavity which forms part of the fioor of the temporal fossa and gives origin to the temporal muscle. The medial angular processes articulate with the lacrimals and form the lateral limits of the nasal notch, bounded in front by a rough, semilunar surface which articulates with the upper ends of the nasal bones and the frontal (nasal) processes of the maxillae.
In the concavity of the notch hes the nasal portion of the frontal, which projects somewhat beneath the nasal bones and the nasal processes of the maxillfe. It is divisible into three parts: — a median frontal (nasal) spine, which descends in the nasal septum between the crest of the nasal bones in front and the vertical plate of the ethmoid behind, and, on the posterior aspect of the process, two alee, one on either side of the median ridge from which the frontal (nasal) spine is continued. Each ala forms a small grooved surface which enters into the formation of the roof of the nasal fossa.
The cerebral surface presents in the middle line a vertical groove — the sagittal sulcus — which descends from the middle of the upper margin and lodges the superior sagittal (longitudinal) sinus. Below, the groove is succeeded by the frontal crest, which terminates near the lower margin at a small notch, converted into a foramen by articulation with the ethmoid.
The foramen is called the foramen caecum, and is generally closed below, but sometimes transmits a vein from the nasal fossje to the superior sagittal (longitudinal) sinus. The frontal crest serves for the attachment of the anterior part of the falx cerebri. On each side of the middle line the bone is deeply concave, presentino: depressions for the cerebral convolutions and numerous small furrows which, running medially from the lateral margin, lodge branches of the middle meningeal vessels. At the upper part of the surface, on either side of the frontal sulcus, are some depressions for Pacchionian bodies.
Ethmoidal notch
notch [incisura ethmoidalis], form the greater part of the roof of each orbit. When the bones are articulated, the notch is filled up by the cribriform plate of the ethmoid, and the half -cells on the upper surface of the lateral mass of the ethmoid are completed by, the depressions or half -cells which occupy the irregular margins of the notch. Traversing these edges transversely are two grooves which complete, with the ethmoid, the anterior and posterior ethmoidal canals. The anterior transmits the anterior ethmoidal nerve and vessels; the posterior transmits the posterior ethmoidal nerve and vessels, and both canals open on the medial wall of the orbit. Farther forward, on either side of the nasal spine, are the openings of the frontal sinuses, two irregular cavities which extend within
the bone for a variable distance and give rise to the superciliary arches (ridges) . Each is lined by mucous membrane and communicates with the nasal fossa by means of a passage called the infundibulum.
The inferior surface of each orbital plate, smooth and concave, presents immediately behind the lateral angular process the lacrimal fossa, for the lacrimal gland. Close to the medial angular process is a depression called the trochlear fossa [fovea trochlearis], which gives attachment to the cartilaginous pulley for the superior oblique muscle. The superior surface of each plate is convex and strongly marked by eminences and depressions for the convolutions on the orbital surface of the cerebrum.
Borders. — The articular border of the frontal portion (parietal margin) forms a little more than a semicircle. It is thick, strongly serrated, and bevelled so as to overlap the parietal above and to be overlapped by the edge of that bone below. The border is continued inferiorly into a triangular rough surface on either side, which articulates with the great wing of the sphenoid. The posterior border of the orbital portion is thin and articulated with the lesser wing of the sphenoid.
Blood-supply. — The blood-vessels for the supply of the vertical portion are derived from the frontal and supra-orbital arteries, which enter on the outer surface, and from the middle and small meningeal, which enter on the cerebral surface. The horizontal portion receives branches from the ethmoidal, and other branches of the ophthalmic, as well as from the meningeal.
Articulations. — The frontal articulates with the parietal, sphenoid, ethmoid, lacrimal, zygomatic (malar), maxilla, and nasal bones. Also, with the epipteric bones when present, and occasionally with the squamous portion of the temporal, and with the sphenoidal concha when it reaches the orbit.
Ossification. — The frontal is ossified from two nuclei deposited in the outer layer of the membranous wall of the cranium, in the situations ultimately known as the frontal eminences. These nuclei appear about the eighth week, and ossification spreads quickly through the membrane. At birth the bones are quite distinct, but subsequently they articulate with each other in the median line to form the metopie suture. In the majority of cases the suture is obliterated by osseous union, which commences about the second year, though in a few cases the bones remain distinct throughout life.
After the two halves of the bone have united, osseous material is deposited at the lower end of the metopie suture to form the frontal spine, which is one of the distinguishing features of the human frontal bone. The spine appears about the twelfth year, and soon consolidates with the frontal bone above. Accessory nuclei are sometimes seen between this bone and the lacrimal and may persist as Wormian ossicles.
The frontal sinuses appear about the seventh year as prolongations upward from the hiatus semilunaris and increase in size up to old age. As they grow they extend in three directions, viz., upward, laterally, and backward along the orbital roof. A bony septum, usually complete, separates the sinuses of the two sides, and they are larger in the male than in the female. The supercihary arches are not altogether reliable guides as to the size of the sinuses, since examples are seen in which the arches are low and the sinuses large. In fig. 78 an example of unusually large sinuses is figured, illustrating the extension upward, laterally, and backward.
THE SPHENOID
The sphenoid [os sphenoidale] (figs. 79, 80, 81, 82) is situated in the base of the skull and takes part in the formation of the floor of the anterior, middle, and posterior cranial fossae, of the temporal and nasal fossae, and of the cavity of the orbit. It is very irregular in shape and is described as consisting of a central part or body, two pairs of lateral expansions called the great and small wings, and a pair of processes which project downward, called the pterygoid processes.
The body, irregularly cuboidal in shape, is hollowed out into two large cavities known as the sphenoidal sinuses, separated by a thin sphenoidal septum and opening in front by two large apertures into the nasal fossae. The superior sur-
face presents the following points for examination: In front is seen a prominent spine, the ethmoidal spine, which articulates with the hinder edge of the cribriform plate of the ethmoid. The sm-face behind this is smooth and frequently presents two longitudinal grooves, one on either side of the median line, for the olfactory bulbs; it is limited posteriorly by a ridge, the limbus sphenoidalis, which forms the anterior border of the narrow transverse optic groove [sulcus chiasmatis], above and behind which lies the optic commissure. The groove terminates on each side in the optic foramen, which perforates the root of the small wing and transmits the optic nerve and the ophthalmic artery. Behind the optic groove is the tuberculum sellae, indicating the line of junction of the two parts of which the body is formed (pre- and post-sphenoid); and still further back, a deep depression, the hypophyseal fossa [sella turcica], which lodges the hypophysis cerebri. The floor of the fossa presents numerous foramina for blood-vessels, and at birth the superior orifice of a narrow passage called the basi-pharyngeal canal opens on the tuberculum. The posterior boundary of the fossa is formed by a quadrilateral plate of bone, the dorsum sellae (dorsum
Posterior clinoid process
ephippii), the posterior surface of which is sloped in continuation mth the basilar groove of the occipital bone. The superior angles of the plate are surmounted by the posterior clinoid processes, which give attachment to the tentorium cerebelli and the interclinoid ligaments. Below the clinoid process, on each side of the dorsum sellffi (sometimes at the suture between the sphenoid and apex of petrosal), a notch is seen, converted into a foramen by the dura mater, for the passage of the sixth cranial nerve, and at the inferior angle the posterior petrosal process, which articulates with the apex of the petrous portion of the temporal bone, forming the inner boundary of the foramen lacerum. The dorsum sellse is slightly concave posteriorly (the clivus) and supports the pons Varolii and the basilar artery.
The inferior surface presents in the middle line a prominent ridge known as the rostrum, which is received into a deep depression between the alee of the vomer. On each side is the vaginal process of the medial pterygoid plate, directed horizontally and medially, which, with the alee of the vomer, covers the greater part of this surface. The remainder is rough and clothed by the mucous membrane of the roof of the pharynx.
The anterior surface is divided into two lateral halves by the sphenoidal crest, a vertical ridge of bone continuous above with the ethmoidal spine, below with the rostrum, and articulating in front with the perpendicular plate of the ethmoid. The surface on each side presents a rough lateral margin for articulation with the lateral mass of the ethmoid and the orbital process of the palate bone. Elsewhere it is smooth, and enters into the formation of the roof of the
sinuses.
The body is not hollowed until after the sixth year, but from that time the sinuses increase in size as age advances. Except for the apertures just mentioned, they are closed below and in front by the two sphenoidal conchse (turbinate bones), originally distinct, but in the adult usually incorporated with the sphenoid.
The posterior surface is united to the basilar process of the occipital, up to the twentieth year, by a disc of hyaline cartilage forming a synchondrosis, but afterward this becomes ossified and the two bones then form one piece.
Dorsum sellee
The lateral surface of the body gives attachment to the two wings, and its fore part is free where it forms the medial boundary of the superior orbital fissure and the posterior part of the medial wall of the orbit. Above the line of attachment of the great wing is a broad groove which lodges the internal carotid artery and the cavernous sinus, called the carotid groove. It is deepest where it curves behind the root of the process, and this part is bounded along its lateral margin by a slender ridge of bone named the lingula, which projects backward in the angle between the body and the great wing.
The small or orbital wings [alse parvse] are two thin, triangular plates of bone extending nearly horizontally and laterally on a level with the front part of the upper surface of the body. Each arises medially by two processes or roots, the upper thin and flat, the lower thick and rounded.
Near the junction of the lower root with the body is a small tubercle for the attachment of the common tendon of three ocular muscles — viz., the superior, medial, and upper head of lateral rectus — and between the two roots is the optic foramen. The lateral extremity, slender and pointed, approaches the great wing, but, as a rule, does not actually touch it. The superior surface, smooth and slightly concave, forms the posterior part of the anterior fossa of the cranium. The inferior surface constitutes a portion of the roof of each orbit and overhangs
the superior orbital (or sphenoidal) fissure, the elongated opening between the small and great wings. The anterior border is serrated for articulation with the orbital plate of the frontal, and the posterior border, smooth and rounded, is received into the Sylvian fissure of the cerebrum. Moreover, the posterior border forms the boundary between the anterior and middle cranial fossse and is prolonged at its medial extremity to form the anterior clinoid process, which gives attachment to the tentorium cerebelli and the interclinoid ligaments. Between the tuberoulum sellse and the anterior chnoid process is a semicircular notch which represents the termination of the carotid groOve. It is sometimes converted into a foramen, the caroticoclinoid foramen, by a spicule of bone which bridges across from the anterior clinoid to the middle clinoid process; the latter is a small tubercle frequently seen on each side, in front of the hypophyseal fossa, and slightly posterior to the tuberculum sellse; the foramen transmits the internal carotid artery, and the spicule of bone which may complete the foramen is formed by ossification of the carotioo-clinoid ligament.
The great or temporal wings [alse magnse], arising from the lateral surface of the body, extend laterally and then upward and forward. The posterior part is placed horizontally and projects backward into the angle between the squamous and petrous portions of the temporal bone. From the under aspect of its pointed extremity the spine, which is grooved medially by the chorda tympani nerve (Lucas), projects downward. The spine serves for the attachment of the sphenomandibular ligament and a few fibres of the tensor veli -palatini. Each wing presents for examination four surfaces and four borders.
Sphenoidal sinus
The cerebral or superior surface is smooth and concave. It enters into the formation of the middle cranial fossa, supports the temporo-sphenoidal lobe of the cerebrum, and presents several foramina. At the anterior and medial part is the foramen rotundum for the second division of the fifth nerve, and behind and lateral to it, near the posterior margin of the great wing, is the large foramen ovale, transmitting the third division of the fifth, the small meningeal artery, and an emissary vein from the cavernous sinus.
Behind and lateral to the foramen ovale is the small circular foramen spinosum, sometimes incomplete, for the passage of the middle meningeal vessels, and the recurrent branch of the third division of the fifth. Between the foramen ovale and the foramen rotundum is the inconstant foramen Vesalii, which transmits a small emissary vein from the cavernous sinus; and on the plate of bone, behind and medial to the foramen ovale (spheno-petrosal lamina), a minute canal is occasionally seen — the canaliculus innominatus — -through which the small superficial petrosal nerve escapes from the skull. When the canaliculus is absent, the nerve passes through the foramen ovale.
The anterior surface looks medially and forward and consists of two divisions — a quadrilateral or orbital surface, which forms the chief part of the lateral wall of the orbit, and a smaller, inferior or spheno-maxillary surface, situated above the pterygoid process and perforated by the foramen rotundum; this inferior part forms the posterior wall of the pterygo-palatine fossa.
The lateral or squamo-zygomatic surface is divided by a prominent infratemporal ridge into a superior portion, which forms part of the temporal fossa and affords attachment to the temporal muscle, and an inferior part, which looks downward into the zygomatic fossa and gives attachment to the external pterygoid muscle; the inferior part joins the lateral surface of the lateral pterygoid plate, and presents the inferior orifices of the foramen ovale, foramen spinosum, and foramen of Vesalius.
Borders. — The posterior border extends from the body to the spine. By its lateral third it articulates with the petrous portion of the temporal bone, whilst the medial two-thirds form the anterior boimdary of the foramen laoerum. The squamosal border is serrated behind and bevelled in front for articulation with the squamous portion of the temporal bone, whilst its upper extremity, or summit, is bevelled on its inner aspect, for the anterior inferior angle of the parietal. Immediately in front of the upper extremity is a rough, triangular, sutural area for the frontal, the sides of which are formed by the upper margins of the superior, anterior, and lateral surfaces respectively. The zygomatic or anterior border separates the orbital and temporal surfaces and articulates with the zygomatic, and by its lower angle, in many skulls, also with the maxilla. Below the anterior border is a short horizontal ridge, non-articular, which separates the spheno-maxillary and zygomatic surfaces. Above and medially, where the orbital and cerebral surfaces meet, is the sharp medial border, which forms the lower boundarj' of the superior orbital fissure, serving for the passage of the third, fourth, three branches of the first division of the fifth, and the sixth cranial nerves, the orbital branch of the middle meningeal artery, a recurrent branch from the lacrimal artery, some twigs from the cavernous plexus of the sympathetic, and one or two ophthalmic veins. Near the middle of the border is a small tubercle for the origin of the lower head of the lateral rectus muscle.
The pterygoid processes project downward from the junction of the bodj' and the great wings. Each consists of two plates, one shorter and broader, the lateral pterygoid plate [lamina lateralis], the other longer and narrower, the medial pterygoid plate [lamina medialis]. They are united in front, but diverge behind so as to enclose between them the pterygoid fossa in which lie the internal "pterygoid and tensor palati muscles. The lateral pterygoid plate is turned a httle laterally and by its lateral surface, which looks into the zygomatic fossa, affords attachment to the ezteimal pterygoid muscle, whilst from its medial surface the internal pterygoid takes origin.
The posterior border of the lateral pterygoid plate frequently presents one or more bony projections, which represent ossified parts of the pterygo-spinous ligaments, and occasionally one may extend across to the spine and complete the bony boundary of the pterygospinous foramen. The medial pterygoid plate is prolonged below into a slender, hook-like or hamular process, smooth on the under aspect for the tendon of the tensor palati, which plays round it. Superiorly, the medial plate extends medially on the under surface of the body, forming the vaginal process, which articulates with the ala of the vomer and the sphenoidal process of the palate. The vaginal process presents, on the under surface, a small groove which, with the sphenoidal process of the palate, forms the pharyngeal canal for the transmission of branches of the spheno-palatine vessels and ganglion. The medial surface of the medial pterygoid plate forms part of the lateral boundary of the nasal fossa, and the lateral surface, the medial boundary of the pterygoid fossa. The posterior border presents superiorly a well-marked prominence, the pterygoid tubercle, above and to the lateral side of which is the posterior orifice of the pterygoid canal. The latter pierces the bone in the sagittal direction at the root of the medial pterygoid plate and transmits the Vidian vessels and nerve. Some distance below the tubercle is a projection, called the processus tubarius, which supports the cartilage of the tuba auditiva (Eustachian tube). From the lower third of the posterior border and from the hamular process, the superior constrictor of the pharynx takes origin, and from the depression known as the scaphoid fossa, situated in the upper part of the recess between the two pterygoid plates, the tensor palati arises.
Pterygoid canal
In front, the two plates are joined above, but diverge below, leaving a gap — the pterygoid notch — occupied, in the articulated skull, by the pyramidal process of the palate. Superiorly, they form a triangular surface which looks into the pterygo-palatine fossa and presents the anterior orifice of the pterygoid canal. The anterior border of the medial pterygoid plate articulates with the posterior border of the vertical plate of the palate.
Blood-supply. — The sphenoid is supplied by branches of the middle and small meningeal arteries, the deep temporal and other branches of the internal maxillary artery — viz., the Vidian and spheno-palatine. The body of the bone also receives twigs from the internal carotid.
zygomatic, epipteric bone when present, and occasionally with the maxilla.
Ossification.^The sphenoid is divided, up to the seventh or eighth month of intra-uterine life, into an anterior or pre-sphenoid portion, including the part of the bddy in front of the tuberculum sellai and the small wings, and a post-sphenoid portion, the part behind the tuberculum sellae including the hypophyseaf fossa and the great wings. The two portions of the body join together before birth, but in many animals the division is persistent throughout life.
In the formation of the post-sphenoidal portion both cartilage and membrane bone participate, the pterygoid plates being formed in membrane, while the rest of the portion, together with the hamular process, ossifies from cartilage. (Fawoett.) At about the eighth week a
centre appears at the base of each greater wing (ali-sphenoid), and at about the same time a pair of centres appear in the body (basi-sphenoid) and later one in each hngula (sphenotic). The medial pterygoid plates are pre-formed in cartilage, in which a centre appears for the hamular process, but the rest of the plate is formed from membrane bone which invests the cartilage. The lateral plate is formed in membrane and a considerable part of the greater wing is also membranous in origin (see epipteric bone).
Vaginal process
body from the sella turcica and sometimes reaches its under surface. It contains a process of dura mater, and represents the remains of the canal in the base of the cranium, through which the diverticulum of Rathke extended upward to form part of the hypophysis.
The great wings are joined to the lingulae by cartilage, but in the course of the first year bony union takes place. About the same time the orbito-sphenoids meet and fuse in the middle line to form the jugum sphenoidale, which thus excludes the anterior part of the pre-sphenoid from the cranial cavity. For some years the body of the pre-sphenoid is broad and rounded inferiorly (fig. 85). The posterior clinoid processes chondrify separately, a fact which throws some hght on the occasional absence of these processes.
The sphenoidal conchEe (or turbinate bones; bones of Bertin) (figs. 86, 87) may be obtained as distinct ossicles about the fifth year, and resemble in shape two hollow cones flattened in three planes. At this date each is wedged in between the under surface of the pre-sphenoid and the orbital and sphenoidal processes of the palate bone, with the apex of the cone directed backward as far as the vaginal process of the medial pterygoid plate. Of its three surfaces, the lateral is in relation with the pterygo-palatine fossa, and occasionally extends upward between the sphenoid and the lamina papyracea of the ethmoid, to appear on the medial wall of the orbit (fig. 105). The inferior surface forms the upper boundary of the spheno-palatine foramen and enters into formation of the posterior part of the roof of the nasal fossa. The
the cone is in contact with the lateral mass of the ethmoid.
The deposits of earthy matter from which the sphenoidal conchae are formed appear at the fifth month. At birth each forms a small triangular lamina in the peiichondrium of the ethmovomerine plate near its junction with the presphenoid, and partially encloses a small recess from the mucous membrane of the nose, which becomes the sphenoidal sinus. By the third year the bone has surrounded the sinus, forming an osseous capsule, conical in shape, the circular orifice which represents the base becoming the sphenoidal foramen. As the cavity enlarges the medial wall is absorbed, and the medial wall of the sinus is then formed by the pre-sphenoid.
The bones are subsequently ankylosed in many skulls with the ethmoid, whence they are often regarded as parts of that bone. More frequently they fuse with the pre-sphenoid, and less frequently with the palate bones. After the twelfth year they can rarely be separated from the skull without damage. In many disarticulated skulls they are so broken up that a portion is found on the sphenoid, fragments on the palate bones, and the remainder attached to the ethmoid. Sometimes, even in old skulls, they are represented by a very thin triangular plate on each side of the rostrum of the sphenoid (fig. 87).
THE EPIPTERIC AND WORMIAN BONES
The epipterics are scale-like bones which occupy the antero-lateral fontanellesEach epipteric bone is wedged between the squamo-zygomatic portion of the temporal, frontal, great wing of sphenoid, and the parietal, and is present in most skulls between the second and fifteenth year. After that date it may persist as a separate ossicle, or unite with the sphenoid, the frontal, or the squamo-zygomatic. The epipteric bone is pre-formed in membrane, and appears as a series of bony granules in the course of the first year.
The Wormian or sutural bones [ossa suturarum] are small, irregularly shaped ossicles, often found in the sutures of the cranium, especially those in relation with the parietal bones. They sometimes occur in great numbers; as many as a hundred have been counted in one skull. They are rarely present in the sutures of the face.
The temporal bone [os temporale], situated at the side and the base of the cranium, contains the organ of hearing and articulates with the lower jaw. It is usually divided into three parts — viz., the squamous portion, forming the anterior and superior part of the bone, thin and expanded and prolonged externally into the zygomatic process; the mastoid portion, the thick conical posterior part, behind the external aperture of the ear; and a pyramidal projection named the petrous portion, situated in a plane below and to the medial side of the two parts already mentioned, and forming part of the base of the skull.
When it is considered in reference to its mode of development, the temporal bone is found to be built up of three parts (figs. 88, 89, 90), which, however, do not altogether correspond to the arbitrary divisions of the adult bone. The three parts are named squamosal, petrosal,
cranium, where it forms a large part of the so-called mastoid portion of the temporal bone. Besides containing the internal ear, it bears on its cranial side a foramen for the seventh and eighth cranial nerves (internal auditory meatus), and on its outer side two openings — the fenestra vestibuli and fenestra cochleae (fig. 91). The squamosal is a superadded element and is formed as a membrane bone in the lateral wall of the cranium. It is especially developed in man in consequence of the large size of the brain, and forms the squamous division of the adult bone, and by a triangular shaped process which is prolonged behind the aperture of the ear it also contributes to the formation of the mastoid portion. It is obvious, therefore, that the mastoid is not an independent element, but belongs in part to the petrous, and in part to the squamous. The tympanic portion, also superadded, is a ring of bone developed in connection with the external auditory meatus, and eventually forms a plate constituting part of the bony wall of this passage. These three parts are easily separable at birth, but eventually become firmly united to form a single bone which affords little trace of its complex origin. Lastly a process of bone, developed in the second visceral arch, coalesces with the under surface of the temporal bone and forms the styloid process.
Styloid process Mastoid process
The squamous portion [squama temporalis] is flat, scale-like, thin, and translucent. It is attached almost at right angles to the petrous portion, forms part of the side wall of the skull and is limited above by an uneven border which describes about two-thirds of a circle. The outer surface is smooth, slightly convex near the middle, and forms part of the temporal fossa. Above the external auditory meatus it presents a nearly vertical groove for the middle temporal artery. Connected with its lower part is a narrow projecting bar of bone known as the zygomatic process. At its base the process is broad, directed lateralljr, and flattened from above downward. It soon, however, becomes twisted on itself and runs forward, almost parallel with the squamous portion. This part is much narrower and compressed laterally so as to present medial and lateral surfaces with upper and lower margins. The lateral surface is subcutaneous; the medial looks toward the temporal fossa and gives origin to the masseter muscle. The lower border is concave and rough for fibres of the same muscle, whilst the upper border, thin and prolonged further forward than the lower, receives the temporal fascia. The extremity of the process is serrated for articulation with the zygomatic bone. At its base the zygomatic process presents three roots — anterior, middle, and posterior.
The anterior, continuous with the lower border, is short, broad, convex, and directed medially' to terminate in the articular tubercle, which is covered with cartilage in the recent state, for articulation with the condyle of the lower jaw. The middle root, sometimes very prominent, forms the post-glenoid process. It separates the articular portion of the mandibular fossa from the external auditory meatus and is situated immediately in front of the petro-tympanic (Glaserian) fissure. The posterior root, prolonged from the upper border, is strongly marked and extends backward as a ridge above the external auditory meatus. It is called the temporal ridge (supra-mastoid crest), and marks the arbitrary line of division between the squamous and mastoid portions of the adult bone. It forms part of the posterior boundary of the temporal fossa, from which, as well as from the ridge, fibres of the temporal muscle arise. Where the anterior root joins the zygomatic process is a slight tubercle — the preglenoid tubercle — for the attachment of the temporo-mandibular ligament, and between the anterior and middle roots is a deep oval depression, forming the part of the mandibular fossa for the condyle of the lower jaw. The mandibular fossa is a considerable hollow, bounded in front by the articular tubercle and behind by the tympanic plate which separates it from the external auditory meatus. It is divided into two parts by a narrow slit — the petro-tympanic (Glaserian) fissure. The anterior part [facies articularis], which belongs to the squamous portion, is articular, and, like the articular tubercle, is coated with cartilage. The posterior
part, formed by the tympanic plate, is non-articular and lodges a lobe of the parotid gland. Immediately in front of the articular tubercle is a small triangular surface which enters into the formation of the roof of the zygomatic fossa.
The inner or cerebral surface of the squamous portion is marked by furrows for the convolutions of the brain and grooves for the middle meningeal vessels. At the upper part of the surface the inner table is deficient and the outer table is prolonged some distance upward, forming a thin scale, with the bevelled surface looking inward to overlap the corresponding edge of the parietal. Anteriorly the border is thicker, serrated, and slightly bevelled on the outer side for articulation with the posterior border of the great wing of the sphenoid. Posteriorly it joins the rough serrated margin of the mastoid portion to form the parietal notch. The line separating the squamous from the petrous portion is indicated at the lower part of the inner surface by a narrow cleft, the internal petro-squamous suture, the appearance of which varies in different bones according to the degree of persistence of the original line of division.
The mastoid portion [pars mastoidea] is rough and convex. It is bounded above by the temporal ridge and the parieto-mastoid suture; in front, by the external auditory meatus and the tympano-mastoid fissure; and behind, by the suture between the mastoid and occipital. As already pointed out, it is formed by the squamous portion in front and by the base of the petrosal behind, the line of junction of the two component parts being indicated on the outer surface by the external petro-squamous suture (squamo-mastoid). The appearance of the suture varies, being in some bones scarcely distinguishable, in others, a series
of irregular depressions, whilst occasionally it is present as a well-marked fissure (fig. 92) directed obliquely downward and forward. The mastoid portion is prolonged downward behind the external acoustic meatus into a nipple-shaped projection, the mastoid process, the tip of which points forward as well as downward. The process is marked, on its medial surface, by a deep groove, the mastoid notch (digastric fossa), for the origin of the digastric muscle, and again medially by the occipital groove for the occipital artery.
The outer surface is perforated by numerous foramina, one, of large size, being usually situated near the posterior border and called the mastoid foramen. It transmits a vein to the transverse (lateral) sinus and the mastoid branch of the occipital artery. The mastoid portion gives attachment externally to the auricularis posterior (retrahens aurem) and occipitalis, and, along with the mastoid process, to the sterno-mastoid, splenius capitis, and longissimus capitis {trachelo-mastoid) . Projecting from the postero-superior margin of the external auditory meatus there is frequently a small tubercle — the supra-meatal spine — behind which the surface is depressed to form the mastoid (supra-meatal) fossa.
The inner surface of the mastoid portion presents a deep curved sigmoid groove, in which is lodged a part of the transverse sinus ; the mastoid foramen is seen opening into the groove. The interior of the mastoid portion, in the adult, is usually occupied by cavities lined by mucous membrane and known as the mastoid air-cells (fig. 97). These open into a small chamber — the mastoid antrum — which communicates with the upper part of the tympanic cavity. The mastoid cells are arranged in three groups: (1) antero-superior, (2) middle, and (3) apical. The [apical cells, situated at the apex of the mastoid process, are small and usually contain marrow.
Borders. — -The superior border is broad and rough for articulation with the hinder part of the inferior border of the parietal bone. The posterior border, very uneven and serrated, articulates with the inferior border of the occipital bone, extending from the lateral angle to the jugular process.
The petrous portion [pars petrosa; pyramis] is a pyramid of very dense bone presenting for examination a base, an apex, three (or four) surfaces, and three (or four) borders or angles. Two sides of the pyramid look into the cranial cavity, the posterior into the posterior cranial fossa, and the anterior into the middle cranial fossa. The inferior surface appears on the under surface of the cranium . The medial and posterior walls of the tympanic cavity in the temporal bone are sometimes described as a fourth side of the pyramid. The base forms a part of the lateral surface of the cranium; the apex is placed medially.
The posterior surface of the pyramid is triangular in form, bounded above by the superior angle and below by the posterior angle Near the middle is an obliquely directed foramen [porus acusticus internus] leading into a short canal — ■ the internal auditory meatus — at the bottom of which is a plate of bone, pierced by numerous foramina, and known as the lamina cribrosa. The canal transmits the facial and auditory nerves, the pars intermedia, and the internal auditory artery. The bottom of the internal auditory meatus can be most advantageously studied in a temporal bone at about the time of birth, when the canal is shallow and the openings relatively wide.
The fundus of the meatus is divided by a transverse ridge of bone, the transverse crest, into a superior and inferior fossa. Of these, the superior is the smaller, and presents anteriorly the beginning of the facial canal (aqueduct of Fallopius), which transmits the seventh nerve. The rest of the surface above the crest is dotted with small foramina (the superior vestibular area) which transmit nerve-twigs to the recessus elliptious (fovea hemielliptica) and the ampuUae of the superior and lateral semicircular canals (vestibular division of the auditory nerve). Below the crest there are two depressions and an opening. Of these, an anterior curled tract (the spiral cribriform tract) with a central foramen (foramen oentrale cochleare) marks the base of the cochlea; the central foramen indicates the orifice of the canal of the modiolus, and the smaller foramina transmit the cochlear twigs of the auditory nerve. The posterior opening (foramen singulare) is for the nerve to the ampulla of the posterior semicircular canal. The middle depression (inferior vestibular area) is dotted with minute foramina for the nerve-twigs to the saccule, which is lodged in the recessus sphsericus (fovea hemisphaerica). The inferior fossa is subdivided by a low vertical crest. The fossa in front of the crest is the fossula cochlearis, and the recess behind it is the fossula vestibularis.
Behind and lateral to the meatus is a narrow fissure, the aquseductus vestibuli, covered by a scale of bone. In the fissure lies the ductus endolymphaticus, a small arteriole and venule, and a process of connective tissue which unites the dura mater to the sheath of the internal ear. Occasionally a bristle can be passed through it into the vestibule. Near the upper margin, and opposite a point about midway between the meatus and the aqueduct of the vesti-
bule, is an irregular opening, the fossa subarcuata, the remains of the floccular fossa, a conspicuous depression in the foetal bone. In the adult the depression usually lodges a process of dura mater and transmits a small vein, though in some bones it is almost obhterated.
the back part of the floor of the middle fossa of the cranium.
Upon the anterior surface of the pyramid will be found the following points of interest, proceeding from the apex toward the base of the pyramid: — (1) a shallow trigeminal impression for the semilunar (Gasserian) ganglion of the trigeminal nerve; (2) two small grooves running backward and laterally toward two small foramina overhung by a thin osseous lip, the larger and medial of which, known as the hiatus canalis facialis, transmits the great superficial petrosal nerve and the petrosal branch of the middle meningeal artery, whilst the smaller and lateral foramen is for the small superficial petrosal nerve; (3) behind and lateral to these is an eminence — the eminentia arcuata — best seen in young bones, corresponding to the superior semicircular canal in the interior; (4) still more laterally is a thin transulcent plate of bone, roofing in the tympanic cavity, and named the tegmen tympani.
Spiral cribriform tract
The inferior or basilar surface of the pyramid is very irregular. At the apex it is rough, quadrilateral, and gives attachment to the tensor tympani, levator veil palatini, and the pharyngeal aponeurosis. Behind this are seen the large circular orifice of the carotid canal for the transmission of the carotid artery and a plexus of sympathetic nerves, and on the same level, near the posterior border, a small three-sided depression, the canaliculus cochleae, which transmits a small vein from the cochlea to the internal jugular. Behind these two openings is the large elliptical jugular fossa which forms the anterior and lateral part of the bony wall of the jugular foramen, in which is contained a dilatation on the commencement of the internal jugular vein; on the lateral wall of the jugular fossa is a minute foramen, the mastoid canaliculus, for the entrance of the auricular branch of the vagus (Arnold's nerve) into the interior of the bone. Between the inferior aperture of the carotid canal and the jugular fossa is the sharp carotid ridge, on which is a small depression, the fossula petrosa, and at the bottom of this a minute opening, the tympanic canaliculus, for the tympanic branch of the glosso-pharyngeal or Jacobson's nerve, and the small tympanic branch from the ascending pharyngeal artery. Behind the fossa is the rough jugular surface for articulation with the jugular process of the occipital bone, on the lateral side of which is the prominent cylindrical spur known as the styloid process with the stylo-mastoid foramen at its base. The facial nerve, and sometimes the auricular branch of the vagus, leave the skull, and the stylo-mastoid artery enters it by this foramen. Running backward from the foramen are the mastoid and occipital grooves already described.
The tympanic surface of the pyramid, forming the medial and posterior walls [paries labyrinthica] of the tympanic cavity, is shown by removing the tympanic plate (fig. 91). It presents near the base an excavation, known as the tympanic or mastoid antrum, covered by the triangular part of the squamous below and behind the temporal line. The opening of the antrum into the tympanic cavity is situated immediately above the fenestra vestibuli, an ovalshaped opening which receives the base of the stapes; below the fenestra vestibuli is a convex projection or promontory, marked by grooves for the tympanic plexus of nerves and containing the commencement of the first turn of the cochlea. In the lower and posterior part of the promontory is the fenestra cochlesB, closed in the recent state by the secondary membrane of the tj^mpanum. Running downward and forward from the front of the fenestra vestibuli is a thin curved plate of bone [septum canalis musculotubarii], separating two grooves converted
into canals by the overlying tympanic plate. The lower is the groove for the Eustachian tube [semicanalis tubse audi tivse], the communicating passage between the tympanum and the pharynx ; the upper is the semicanalis m. tensoris tympani, and the lateral apertures of both canals are visible in the retiring angle, b-etween the petrous and squamous portions of the bone.
The apex of the pyramid is truncated and presents the medial opening of the carotid canal. The latter commences on the inferior surface, and, after ascending for a short distance, turns forward and medially, tunnelling the bone as far as the apex, and finally opens into the upper part of the foramen lacerum formed between the temporal and sphenoid bones. One or two minute openings in the wall of the carotid canal, known as the carotico -tympanic canaliculi, transmit communicating twigs between the carotid and tympanic plexuses. The upper part of the apex is joined by cartilage to the posterior petrosal process of the sphenoid.
The base is the part of the pyramid which appears laterally at the side of the cranium and takes part in the formation of the mastoid portion. It is described with that chvision of the bone.
Occipital groove
Angles. — The superior angle (border) of the pyramid is the longest and separates the posterior from the anterior surface. It is grooved for the superior petrosal sinus, gives attachment to the tentorium cerebelli, and presents near the apex a semilunar notch upon which the fifth cranial nerve lies. Near its medial end there is often a small projection for the attachment of the petro-sphenoid.al ligament, which arches over the inferior petrosal sinus and the sixth nerve. The posterior angle separates the posterior from the inferior surface, and when articulated with the occipital, forms the groove for the inferior petrosal sinus, and completes the jugular foramen formed by the temporal in front and on the lateral side, and by the occipital behind and on the medial side. The jugular foramen is divisible into three compartments: an anterior for the inferior petrosal sinus, a middle for the glossopharyngeal, vagus and accessory cranial nerves, and a posterior for the internal jugular vein and some meningeal branches from the occipital and ascending pharyngeal arteries. The anterior angle is the shortest and consists of two parts, one joined to the squamous in the petro-squamous suture and a small free part internally which articulates with the sphenoid. A fourth or inferior border may be distinguished, which runs along the line of junction with the tympanic plate and is continued on to the rough area below the apex.
The tympanic portion [pars tympanica] is quadrilateral in form, hollowed out above and behind, and nearly flat, or somewhat concave, in front and below. It forms the whole of the anterior and inferior walls, and part of the posterior wall, of the external auditory meatus, and is separated behind from the mastoid process by the tympano-mastoid (auricular) fissure through which the auricular branch of the vagus in some cases leaves the bone.
In front it is separated by the petro-tympanic fissure from the squamous portion. Through the petro-tympanio fissure the tympanic branch of the internal maxillary artery and the socalled laxator tympani pass. The processus graoihs of the malleus is lodged within it, and a narrow subdivision at its inner end, known as the canal of Huguier, transmits the chorda tympani nerve. The tympanic part presents for examination two surfaces and four borders.
The antero-inferior surface, directed downward and forward, lodges part of the parotid gland. Near the middle it is usually very thin, and sometimes presents a small foramen (the foramen of Huschke), which represents a non-ossified portion of the plate. The posterosuperior surface looks into the external auditory meatus and tympanic cavity, and at its medial end is a narrow groove, the sulcus tympanicus, deficient above, which receives the membrana tympani.
The lateral border is rough and everted, forming the external auditory process for the attachment of the cartilage of the pinna; the superior border enters into the formation of the petro-tympanic fissure; the inferior border is uneven and prolonged into the vaginal process [vagina processus styloideil which surrounds the lateral aspect of the base of the styloid process and gives attachment to the front part of the fascial sheath of the carotid vessels; the medial border, short and irregular, lies immediately below and to the lateral side of the opening of the Eustachian tube, and becomes continuous with the rough quadrilateral area on the inferior aspect of the apex.
The external auditory meatus is formed partly by the tympanic and partly by the squamous portion. It is an elliptical bony tube leading into the tympanum, the extrance of which is bounded throughout the greater part of its circumference by the external auditory process of the tympanic plate. Above, the entrance is limited by the temporal ridge or posterior root of the zygomatic process.
The styloid process is a slender, cylindrical spur of bone fused with the inferior aspect of the temporal immediately in front of the stylo-mastoid foramen. It consists of two parts, basal (tympano-hyal), which in the adult lies under cover of the tympanic plate, and a projecting portion (stylo-hyal) , which varies in length from five to fifty millimetres. When short, it is hidden by the vaginal process, but, on the other hand, it may reach to the hyoid bone. The projecting portion gives attachment to three muscles and two ligaments.
The slylo-pharyngeus arises near the base from the medial and slightly from the posterior aspect; the slylo-hyoid from the posterior and lateral aspect near the middle; and the slyloglossus from the front near the tip. The tip is continuoiis with the stylo-hyoid ligament, which runs down to the lesser cornu of the hyoid bone. A band of fibrous tissue — the stylo-mandibular ligament — passes from the process below the origin of the stylo-glossus to the angle of the lower jaw.
to the cochlea and vestibule.
Other less important twigs are furnished by the middle meningeal, the meningeal branches of the occipital, and by the ascending pharyngeal artery. The squamous portion is supplied, on its internal surface, by the middle meningeal, and externally by the branches of the deep temporal from the internal maxillary.
Articulations. — The temporal bone articulates with the occipital, parietal, sphenoid, zygomatic, and, by a movable joint, with the mandible. Occasionally the squamous portion presents a process which articulates with the frontal. A fronto -squamosal suture is common in the skulls of the lower races of men, and is normal in the skulls of the chimpanzee, gorilla, and gibbon.
Ossification. — Of the three parts which constitute the temporal bone at birth, the squamosal and tympanic develop in membrane and the petrosal in cartilage. The squamosal is formed from one centre, which appears as early as the eighth week, and ossification extends into the zygomatic process, which grows concurrently with the squamosal. At first the tympanic border is nearly straight, but soon assumes its characteristic horseshoe shape. At birth the post-glenoid tubercle is conspicuous, and at the hinder end of the squamosal there is a process which comes into relation with the mastoid antrum The centre for the tympanic element appears about the twelfth week. At birth it forms an incomplete ring, open above, and slightly ankylosed to the lower border of the squamosal. The anterior extremity terminates
ence, a groove for the reception of the tympanic membrane.
Up to the middle of the fifth month the periotio capsule is cartilaginous; it then ossifies so rapidly that by the end of the sixth month its chief portion is converted into porous bone. The ossifio material is deposited in four centres, or groups of centres, named according to their relation to the ear-capsule in its embryonic position.
1. The opisthotic appears at the end of the fifth month. The osseous material is seen first on the promontory, and it quickly surrounds the fenestra cochleae from above downward, and forms the floor of the vestibule, the lower part of the fenestra vestibuli, and the internal auditory meatus; it also invests the cochlea. Subsequently a plate of bone arises from it to surround the internal carotid artery and form the floor of the tympanum.
2. The prootic nucleus is deposited behind the internal auditory meatus near the medial limb of the superior semicircular canal. It covers in a part of the cochlea, the vestibule, and the internal auditory meatus, completes the fenestra vestibuli, and invests the superior semicircular canal.
part of the posterior semicircular canal.
At birth the bone is of loose and open texture, thus offering a striking contrast to the dense and ivory-like petrosal of the adult. It also differs from the adult bone in several other particulars. The floccular fossa is widely open and conspicuous. VoltoUni has pointed out that a small canal leads from the floor of the floccular fossa and opens posteriorly on the mastoid surface of the bone; it may open in the mastoid antrum. The hiatus canalis facialis is unclosed
developed, and the jugular fossa is a shallow depression.
After birth the parts grow rapidly. The tympanum becomes permeated with air, the various elements fuse, and the tympanic annulus grows rapidly and forms the tympanic plate. Development of the tympanic plate takes place by an outgrowth of bone from the lateral aspect of the tympanic annulus. This outgro\vth takes place most rapidly from the tubercles or spines at its upper extremities, and in consequence of the slow growth of the lower segment a deep notch is formed; gradually the tubercles coalesce, lateral to the notch, so as to enclose a foramen which persists until puberty, and sometimes even in the adult. In most skuUs a cleft capable of receiving the nail remains between the tympanic element and the mastoid process; this is the tympano-mastoid fissure. The anterior portion of the tympanic plate forms with the inferior border of the squamosal a cleft known as the petro-tympanic fissure, which is subsequently encroached upon by the growth of the petrosal. As the tympanic plate increases in size it joins the lateral wall of the carotid canal and presents a prominent lower edge, known as the vaginal process (sheath of the styloid).
The mastoid process becomes distinct about the first year, coincident with the obliteration of the petro-squamous suture, and increases in thickness by deposit from the periosteum. According to most writers, the process becomes pneumatic about the time of puberty, but it has been shown by Young and Milligan that the mastoid air-cells develop at a much earlier period than is usually supposed. These writers have described specimens in which the air-cells were present, as small pit-like diverticula from the mastoid antrum, in a nine months' foetus and in an infant one year old. In old skulls the air-cells may extend into the jugular process of the occipital bone.
At birth the mastoid antrum is relatively large and bounded laterally by a thin plate of bone belonging to the squamosal (post-auditory process). As the mastoid increases in thickness the antrum comes to lie at a greater depth from the surface and becomes relatively smaller.
THE TYMPANUM
The styloid process is ossified in cartilage from two centres, one of which appears at the base in the tympano-hyal before birth. This soon joins with the temporal bone, and in the second year a centre appears for the stylo-hyal, which, however, remains very small until puberty. In the adult it usually becomes firmly united with the tympano-hyal, but it may remain permanently separate.
The tympanum (middle ear) includes a cavity [cavum tympani] of irregular form in the temporal bone, situated over the jugular fossa, between the petrous portion medially and the tympanic and squamous portions laterally. When fully developed, it is completely surrounded by bone except where it communicates with the external auditory meatus, and presents for examination six walls — lateral, medial, posterior, anterior, superior (roof), and inferior (floor). The lateral and medial wails are flat, but the remainder are curved, so that they run into adjoining surfaces, without their limits being sharply indicated.
The roof or tegmen tympani [paries tegmentalis] is a translucent plate of bone, forming part of the superior surface of the petrous portion and separating the tympanum from the middle fossa of the skull. The floor [paries jugularis] is the plate of bone which forms the roof of the jugular fossa.
The medial wall [paries labyrinthica] is formed by the tympanic surface of the petrous portion. In the angle between it and the roof is a horizontal ridge which extends backward as far as the posterior wall and then turns downward in the angle between the medial and posterior walls. This is the facial (Fallopian) canal, and is occupied by the facial nerve. The other features of this surface — viz., the fenestra vestibuli, the fenestra cochleae, and the promontory — have previously been described with the anterior surface of the petrous portion of the temporal bone.
leads into the mastoid antrum. Immediately below this opening there is a small hoUow cone, the pyramidal eminence, the cavity of which is continuous with the descending limb of the facial canal. The cavity is occupied by the stapedius and the tendon of the muscle emerges at the apex. One or more bony spicules often connect the apex of the pyramid with the promontory.
The roof and floor converge toward the anterior extremity of the tympanum, which is, in consequence, very low; it is occupied by two semicanals, the lower for the Eustachian tube, the upper for the tensor tympani muscle. These channels are sometimes described together as the canalis musculo-tubarius. In carefully prepared bones the upper semicanal is a small horizontal hollow cone (anterior pyramid), 12 mm. in length; the apex is just in front of the fenestra vestibuli, and is perforated to permit the passage of the tendon of the muscle. As a rule, the thin walls of the canal are damaged, and represented merely by a thin ridge of bone. The posterior portion of this ridge projects into the tympanum, and is known as the processus cochleariformis. The thin septum between the semicanal for the tensor tympani and the tube is pierced by a minute opening which transmits the small deep petrosal nerve.
The lateral wall [paries membranaeea] is occupied mainly by the external auditor}' meatus. This opening is closed in the recent state by the tympanic membrane. The rim of bone to which the membrane is attached is incomplete above, and the defect is known as the tympanic notch (notch of Rivinus). Anterior to this notch, in the angle between the squamous portion and the tympanic plate, is the petro-tympanic (Glaserian) fissure, and the small passage which transmits the chorda tympani nerve, known as the canal of Huguier.
Up to this point the description of the middle ear conforms to that in general usage. But Young and Milligan have laid stress on the fact that the middle ear is really a cleft, named by them the "middle-ear cleft," which intervenes between the periotic capsule, on the one hand, and the squamo-zygomatic and tympanic elements of the temporal bone on the other. This cleft, as development proceeds, gives rise to three cavities: — -(1) the mastoid antrum; (2)
tympanum; and (3) the Eustachian tube. They point out that "the cleft is primarily continuous, and however much it may be altered in shape and modified in parts to form these three cavities, that continuity is never lost." It will be clear that the mastoid antrum, according to this view, is not an outgrowth from the tympanum, but is simply the lateral end of the middleear cleft.
The tympanic cavity may be divided into three parts. The part below the level of the superior margin of the external auditory meatus is the tympanum proper ; the portion above this level is the epitympanic recess or attic ; it receives the head of the malleus, the body of the incus, and leads posteriorly into the recess known as the mastoid antrum. The third part is the downward extension known as the hypotympanic recess.
The tympanic or mastoid antrum. — The air-cells which in the adult are found in the interior of the mastoid portion of the temporal bone open into a small cavity termed the mastoid antrum. This is an air-chamber, communicating with the attic of the tympanum, and separated from the middle cranial fossa by the posterior portion of the tegmen tympani. The floor is formed by the mastoid portion of the petrosal, and the lateral wall by the squamosal, below the temporal ridge. In children the outer wall is exceedingly thin, but in the adult it ia of considerable thickness. The lateral semicircular canal projects into the antrum on its
canal is the facial nerve, contained in the facial canal.
The mastoid antrum has somewhat the form of the bulb of a retort (Thane and Godlee) compressed laterally, and opening by its narrowed neck into the attic or epitympanic recess. Its dimensions vary at different periods of hfe. It is well developed at birth, attains its maximum size about the third year, and diminishes somewhat up to adult life. In the adult the plate of bone which forms the lateral wall of the antrum is 12 to 18 mm. (| to J in.) in thickness, whereas at bu-th it is about 1.8 mm. (j^ in.) or less. The deposition of bone laterally occurs, therefore, at average rate of nearly 1 mm. a year in thickness. In the adult the antrum ia about 12 mm. (i in.) from front to back, 9 mm. (f in.) from above downward, and 4.5 mm. (j^V in.) from side to side.
The facial (Fallopian) canal. — This canal begins at the anterior angle of the superior fossa of the internal auditory meatus, and passes forward and laterally above the vestibular portion of the internal ear for a distance of 1.5-2.0 mm. At the lateral end of this portion of its course it becomes dilated to accommodate the geniculate ganglion, and then turns abruptly backward and runs in a horizontal ridge on the medial wall of the tympanurn, lying in the angle between it and the tegmen tympani, immediately above the fenestra vestibuli, and extending as far backward as the entrance to the mastoid antrum. Here it comes into contact with the inferior aspect of the projection formed by the lateral semicircular canal, and then turns vertically downward, running in the angle between the medial and posterior walls of the tympanum to terminate at the stylo-mastoid foramen.
The canal is traversed by the facial nerve. Numerous openings exist in the walls of this passage. At its abrupt bend, or genu, the greater and smaller superficial petrosal nerves escape from, and a branch from the middle meningeal artery enters, the canal, and in the vertical part of its course the cavity of the pyramid opens into it. There is also a small orifice by which the auricular branch of the vagus joins the facial, and near its termination the iter chordae posterius for the chorda tympani nerve leads from it into the tympanum.
THE SMALL BONES OF THE TYMPANUM
The small bones of the tympanum. — These bones, the malleus, incus and stapes, are contained in the upper part of the tympanic cavity. Together they form a jointed column of bone connecting the membrana tympani with the fenestra vestibuli.
The malleus. — This is the most external of the iiuditory ossicles, and hes in relation with the tympanic membrane. Its upper portion, or head, is lodged in the epitympanic recess. It is of rounded shape, and presents posteriorly an elliptical depression for articulation with the incus. Below the head is a constricted portion or neck, from which three processes diverge. The largest is the handle or manubrium, which is slightly twisted and flattened. It forms an obtuse angle with the head of the bone, and lies between the membrana tympani and the mucous membrane covering its inner surface. The tensor tympani tendon is inserted into the manubrium near its junction with the neck on the medial side.
The anterior process (processus gracilis or Folii) is a long, slender, dehoate spiculum of bone (rarely seen of full length except in the fcetus), projecting nearly at right angles to the anterior aspect of the neck, and extending obliquely downward. It lies in the petro-tympanic fissure, and in the adult usually becomes converted into connective tissue, except a small basal stump. The lateral process is a conical projection from the lateral aspect of the base of the manubrium. Its apex is connected to the upper part of the tympanic membrane, and its base receives the lateral ligament of the malleus. The malleus also gives attachment to a superior hgament and an anterior ligament, the latter of which was formerly described as the laxator tymipani muscle.
The incus. — This bone is situated between the malleus externally and the stapes internaUy. It presents for examination a body and two processes. The body is deeply excavated anteriorly for the reception of the head of the malleus. The short process projects backward, and is connected by means of ligamentous fibres to the posterior wall of the tympanum, near the entrance to the mastoid antrum. The long process is slender, and directed downward and inward, and lies parallel with the manubrium of the maUeus. On the medial aspect of the distal extremity of this process is the lenticular process (orbicular tubercle), separate in early life, but
of the stapes.
The stapes is the innermost ossicle. It has a head directed horizontally outward, capped at its outer extremity by a disc resembling the head of the radius. The cup-shaped depression receives the lenticular process of the incus. The base occupies the fenestra vestibuli, and like this opening, the inferior border is straight, and the superior curved. The base is connected with the head by means of two crura, and a narrow piece of bone called the neck. Of the two crura, the anterior is the shorter and straighter. The crura with the base form a stirrup-shaped arch, of which the irmer margin presents a groove for the reception of the membrane stretched across the hollow of the stapes. In the early embryo this hollow is traversed by the stapedial artery. The neck is very short, and receives on its posterior border the tendon of the stapedius muscle.
Development. — The tympanic cavity represents the upper extremity of the first endodermal branchial groove, which becomes converted into a blind pouch, the communication of which with the pharyngeal cavity is the tuba auditiva (Eustachian tube). The thin membrane which separates the endodermal from the ectodermal groove becomes the tympanic membrane, and it is from the upper extremities of the axial skeletons of the first and second branchial arches, which bound the groove anteriorly and posteriorly, that the auditory ossicles are formed, the malleus and incus belonging to the first arch and the stapes to the second (Reichert). The ossicles consequently lie originally in the walls of the cavity, but they are surrounded by a loose spongy tissue, which, on the entrance of air into the cavity, becomes compressed, allowing the cavity to enfold the ossicles. These therefore are enclosed within an epithelium which is continuous medially with that lining the posterior tympanic wall, and laterally with that lining the internal surface of the tympanic membrane.
THE OSSEOUS LABYRINTH
The osseous labyrinth [labyrinthus osseus] (fig. 100) is a complex cavity hollowed out of the petrous portion of the temporal bone and containing the membranous labyrinth, the essential part of the organ of hearing. It is incompletely divided into three parts, named the vestibule, the semicircular canals, and the cochlea.
Fenestra cochleae Fenestra vestibul:
The vestibule. — This is an oval chamber situated between the base of the internal auditory meatus and the medial wall of the tympanum, with which it communicates by way of the fenestra vestibuh. Anteriorly, the vestibule leads into the cochlea, and posteriorly it receives the extremities of the semicircular canals. It measures about 3 mm. transversely, and is somewhat longer antero-posteriorly.
Its medial wall presents at the anterior part a circular depression, the spherical recess (fovea. hemispherica), which is perforated for the passage of nerve-twigs. This recess is separated by a vertical ridge (the crista vestibuli) from the vestibular orifice of the aquseductus
The posterior canal is nearly vertical and lies in a plane nearly parallel to the posterior surface of the petrosal. It is the longest of the three; its upper extremity joins the medial hmb of the superior canal, and opens in common with it into the vestibule. The lower is the ampullated end.
The cochlea. — This is a cone-shaped cavity lying with its base upon the internal auditory meatus, and the apex directed forward and laterally. It measures about five millimetres in length, and the diameter of its base is about the same. The centre of this cavity is occupied by a column of bone — the modiolus — around which a canal is wound in a spiral manner, making about two and a half turns. This is the spiral canal of the cochlea; its first turn is the largest and forms a bulging, the promontory, on the medial wall of the tympanum.
Projecting into the canal throughout its entire length there is a horizontal, shelf-like lamella, the lamina spiralis, which terminates at the apex of the cochlea in a hook-like process, the hamulus. The free edge of the lamina spiralis gives attachment to the membranous cochlea, a canal having in section the form of a triangle whose base is attached to the lateral wall of the spiral canal. By this the spiral canal is divided into a portion above the lamina spiralis, termed the scaia vestibuli, which communicates at its lower end with the osseous vestibule, and a portion below, termed the scala tympani, which abuts at its lower end upon the fenestra cochlea. The two scalae communicate at the apex of the cochlea by the helicotrema. Near the commencement of the scala tympani, and close to the fenestra rotunda, is the cochlear orifice of the canaliculus cochlese (ductus perilymphaticus). In the adult this opens below, near the middle of the posterior border of the petrous bone, and transmits a small vein from the cochlea to the jugular fossa.
The ampulla of the canal, 2.5 mm.
Development. — The membranous internal ear arises in the embryo as a depression of the ectoderm of the surface of the head opposite the fifth neuromere of the hind-brain and later becomes a sac-like cavity, the otocyst, which separates from its original ectodermal connections and sinks deeply into the subjacent mesoderm, a part of which becomes incorporated with it. The rest of the mesodermal tissue which surrounds the otocyst becomes later the petrous portion of the temporal bone, the perilymph and the internal periosteal layer; the osseous labyrinth is therefore merely the portions of the petrous which enclose the cavity occupied by the membranous internal ear.
THE ETHMOID
The ethmoid [os ethmoidale] is a bone of delicate texture, situated at the anterior part of the base of the cranium (figs. 102, 103, 104). Projecting downward from between the orbital plates of the frontal, it enters into the formation of the orbital and nasal fossae. It is cubical in form, and its extreme lightness and delicacy are due to an arrangement of very thin plates of bone surrounding irregular spaces known as air-cells. The ethmoid consists of four parts: the horizontal or cribriform plate, the ethmoidal labyrinth on each side, and a perpendicular plate.
The cribriform plate [lamina cribrosa] forms part of the anterior cranial fossa, and is received into the ethmoidal notch of the frontal bone. It presents on its upper surface, in the median line, the intra-cranial portion of the perpendicular plate, known as the crista galli, a thick, vertical, triangular process with the highest point in front, and a sloping border behind which gives attachment to the f alx cerebri. The anterior border is short and in its lower part broadens out to form two alar processes which articulate with the frontal bone and complete the foramen caecum. The ci'ista galli is continuous behind with a median ridge, and on each side of the middle line is a groove which lodges the olfactory bulb.
The cribriform plate is pierced, on each side, by numerous foramina, arranged in two or three rows, which transmit the filaments of the olfactory nerves descending from the bulb. Those in the middle of the groove are few and are simple perforations, through which pass the nerves to the roof of the nose; the medial and lateral series are more numerous and constitute the upper ends of small canals, which subdivide as they course downward to the upper parts of the septum and the lateral wall of the nasal fossa. At the front part of the cribriform plate is a narrow longitudinal sht, on each side of the crista gaUi, which transmits the anterior ethmoidal (nasal) branch of the ophthalmic division of the fifth nerve. The posterior border articulates with the ethmoidal spine of the sphenoid.
Crest of maxilla
The perpendicular plate (mesethmoid) [lamina perpendicularis is directly continuous with the crista galli on the under aspect of the cribriform plate, so that the two plates cross each other at right angles. The larger part of the perpendicular plate is below the point of intersection and forms the upper third of the septum of the nose. It is quadrangular in form with unequal sides.
Middle nasal concha
The anterior border articulates with the spine of the frontal and the crest of the nasal bones. The inferior border articulates in front with the septal cartilage of the nose and behind with the anterior margin of the vomer. The posterior margin is very thin and articulates with the crest of the sphenoid. This plate, which is generally deflected a little to one side, presents above a number of grooves and minute canals which lead from the inner set of foramina in the cribriform plate and transmit the olfactory nerves to the septum.
pieces of bone, the superior and middle nasal conchse (turbinate bones), and encloses numerous irregularly shaped spaces, known as the ethmoidal cells. These are arranged in three sets — anterior, middle, and posterior ethmoidal cells — and, in the recent state, are lined with prolongations of the nasal mucous membrane. Laterally the labyrinth presents a thin, smooth, quadrilateral plate of bone — the lamina papyracea (os planum) — which closes in the middle and posterior ethmoidal cells and forms a large part of the medial wall of the orbit.
By its anterior border it articulates with the lacrimal, and by its posterior border with the sphenoid; the inferior border articulates with the medial margin of the orbital plate of the maxilla and the orbital process of the palate bone, whilst the superior border articulates with the horizontal plate of the frontal. Two notches in the superior border lead into grooves running horizontally across the lateral mass to the cribriform plate, which complete, with the frontal bone, the ethmoidal canals. The anterior canal transmits the anterior ethmoidal vessels and (nasal) nerve; the posterior transmits the posterior ethmoidal vessels and nerve.
Incisive canal
At the lower part of the lateral surface is a deep groove, which belongs to the middle meatus of the nose, and is bounded below by the thick curved margin of the inferior nasal concha. Anteriorly the middle meatus receives the infundibulum, a sinuous passage which descends from the frontal sinus through the anterior part of the labyrinth. The anterior ethmoidal cells open into the lower part of the infundibulum, and in this way communicate with the nose, whereas the middle ethmoidal cells open directly into the middle or horizontal part of the meatus. In front of the lamina papyracea are seen a few broken cells, which extend under, and are completed by, the lacrimal bone and the frontal process of the maxilla; from this part of the labyrinth an irregular lamina, known as the uncinate process, projects downward and backward. The uncinate process articulates with the ethmoidal process of the inferior nasal concha and forms a small part of the medial wall of the maxillary sinus.
Medially the labyrinth takes part in the formation of the lateral wall of the nasal fossa, and presents the superior and middle nasal conchae (turbinate processes), continuous anteriorly, but separated behind by a space directed forward from the posterior margin. This channel is the superior meatus of the nose and communicates with the posterior ethmoidal cells. The conchse are covered
in the recent state with mucous membrane and present numerous foramina for blood-vessels and, above, grooves for twigs of the olfactory nerves. Each concha has an attached upper border and a free, slightly convoluted, lower border, and in the case of the middle concha, the lower margin has already been noticed on the outer aspect, where it overhangs the middle meatus of the nose. The posterior extremity of the labyrinth articulates with the anterior surface of the body of the sphenoid and is commonly united with the sphenoidal concha.
A rounded prominence on the lateral wall of the middle meatus is known as the bulla ethmoidalis. Antero-inferior to the bulla is a large semilunar depression [hiatus semilunaris] which corresponds to the lower aperture of the infundibulum.
Man}' of the ethmoidal cells are imperfect and are completed by adjacent bones. Those along the superior edge of the lateral mass are the fronto-ethmoidal; those at the anterior border, usually two in number, are known as lacrimo-ethmoidal. Those along the lower edge of the lamina papyraoea are the maxillo-ethmoidal; and posteriorly, are the sphenoethmoidal, completed by the sphenoidal concha, and a palate -ethmoidal cell. The anterior extremity presents one or two incomplete cells closed by the nasal process of the maxilla.
Articulations. — With the frontal, sphenoid, two palate bones, two nasals, vomer, two inferior nasal conchae, two sphenoidal oonohse, two maxills, and two lacrimal bones. The posterior surface of each labyrinth is in relation with the sphenoid on each side of the crest and rostrum, and helps to close in the sphenoidal sinus.
Ossification. — The ethmoid has three centres of ossification. Of these, a nucleus appears in the fourth month of intra-uterine hfe in each labyrinth, first in the lamina papyraoea and afterward extending into the middle concha. At birth each lateral portion is represented by two scroll-like bones, very delicate and covered with irregular depressions, which give it a wormeaten appearance. Six months after birth a nucleus appears in the ethmo-vomerine cartilage lor the vertical plate which gradually extends into the crista galU, and the cribriform plate is formed by ossification extending laterally from this centre, and medially from the labyrinth. The three parts coalesce to form one piece in the fifth or sixth year.
The ethmoid.al cells make their appearance about the third year, and gradually invade the labyrinths. In many places there is so much absorption of bone that the cells perforate the ethmoid in situations where it is overlapped by other bones. Along the lower border, near its articulation with the maxilla, the absorption leads to the partial detachment of a narrow strip known as the uncinate process. Sometimes a second but smaller hook-like process is formed, above and anterior to this, so fragile that it is difficult to preserve it in disarticulated bones. The relations of the uncinate process are best studied by removing the lateral wall of the maxillary sinus.
THE INFERIOR NASAL CONCHA
The inferior nasal concha (inferior turbinate) (fig. 105) is a slender, scroll-Hke lamina, attached by its upper margin to the lateral wall of the nasal fossa, and hanging into the cavity in such a way as to separate the middle from the inferior
meatus of the nose. It may be regarded as a dismemberment of the ethmoidal labyrinth, with which it is closely related. It presents for examination two surfaces, two borders, and two extremities.
THE LACRIMAL 85
and is overhung by the maxillary process. The medial surface is convex, pitted with depressions, and grooved for vessels, which, for the most part, run longitudinally. The superior or attached border articulates in front with the conchal crest of the maxilla, then ascends to form the lacrimal process, which articulates with the lacrimal bone and forms part of the wall of the lacrimal canal. Behind this, it is turned downward to form the maxillary process, already mentioned, which overhangs the orifice of the maxillary sinus and serves to fix the bone firmly to the lateral wall of the nasal fossa. The projection behind the maxillary process is the ethmoidal process, joined in the articulated skull with the uncinate process of the ethmoid across the opening of the maxillary sinus. Posteriorly the upper border articulates with the conchal crest of the palate. The inferior border is free, rounded, and somewhat thickened. The anterior extremity is blunt and flattened, and broader than the posterior extremity, which is elongated, narrow, and pointed.
Ossification. — The inferior nasal conotia is ossified in cartilage from a single nucleus which appears in the fifth month of intra-uterine life. At birth it is a relatively large bone and filla up the lower part of the nasal fossa.
The lacrimal bone [os lacrimale] (fig. 105) is extremely thin and delicate, quadrilateral in shape, and situated at the anterior part of the medial wall of the orbit. It is the smallest of the facial bones.
The orbital surface is divided by a vertical ridge, the posterior lacrimal crest, into two unequal portions. The anterior, smaller portion is deeply grooved to form the lacrimal groove, which lodges the lacrimal sac and forms the commencement of the canal for the naso-lacrimal duct. The portion behind the ridge is smooth, and forms part of the medial wall of the orbit. The ridge gives origin to the orbicularis oculi (pars lacrimalis) muscle and ends below in a hook-like process, the lacrimal hamulus, which curves forward to articulate with the lacrimal tubercle of the maxilla and completes the superior orifice of the naso-lacrimal canal. The medial surface is in relation with the two anterior cells of the ethmoid (lacrimo-ethmoidal), forms part of the infundibulum, and inferiorly looks into the middle meatus of the nose. The superior border is short, and articulates with the medial angular process of the frontal. The inferior border posterior to the crest joins the medial edge of the orbital plate of the maxilla. The narrow piece, anterior to the ridge, is prolonged downward as the descending process to join the lacrimal process of the inferior nasal concha. The anterior border articulates with the posterior border of the frontal process of the maxilla and the posterior border with the lamina papyracea of the ethmoid.
Ossification. — This bone arises in the membrane overlying the cartilage of the fronto-nasal plate, and in its mode of ossification is very variable. As a rule, it is formed from a single nucleus which appears in the third or fourth month of intra-uterine life. Not infrequently, the hamulus is a separate element, and occasionally the bone is divided by a horizontal cleft, a process of the lamina papyracea projecting between the two halves to join the frontal process of the maxilla. More rarely the bone is represented by a group of detached ossicles resembling Wormian bones.
The vomer (fig. 106) (ploughshare bone) is an unpaired flat bone, which lies in the median plane and forms the lower part of the nasal septum. It is thin and irregularly quadrilateral in form, and is usually bent somewhat to one side, though the deflection rarely involves the posterior margin. Each lateral surface is covered in the recent state by the mucous membrane of the nasal cavity, and is traversed by a narrow but well-marked groove, which lodges the naso-palatine nerve from the spheno-palatine ganglion.
The superior border, by far the thickest part of the bone, is expanded laterally into two alse. The groove between them receives the rostrum of the sphenoid, and the margin of each ala comes into contact with the sphenoidal process of the palate and the vaginal process of the medial pterygoid plate. The inferior border is uneven and lies in the groove formed by the crests of the maxillary and palate bones of the two sides. The anterior border slopes downward and forward and is grooved below for the septal cartilage of the nose; above it is united with the perpendicular plate of the ethmoid. The posterior border, smooth, rounded, and covered by mucus membrane, separates the posterior nares. The anterior and inferior borders meet at the anterior extremity of the bone which forms a short vertical ridge behind the incisor crest of the maxillae. From near the anterior extremity, a small projection passes downward between the incisive foramina.
Inferior border
Blood-supply. — The arterial supply of the vomer is derived from the anterior and posterior ethmoidal and the spheno-palatine arteries. Branches are also derived from the posterior palatine through the foramen incisivum.
Ossification. — The vomer is ossified from two centres which appear about the eighth week in the membrane investing the ethmo-vomerine cartilage. The two lamellae unite below during the third month and form a shallow bony trough in which the cartilage lies. In the process of growth the lamells extend upward and forward and gradually fuse to form a rectangular plate of bone, the cartilage enclosed between them undergoing absorption at the same time. The alae on the superior margin and the groove in front are evidence of the original bilaminar condition.
The nasal (figs. 107 and 108) are two small oblong bones situated at the upper part of the face and forming the bridge of the nose. Each bone is thicker and narrower above, thinner and broader below, and presents for examination two surfaces and four borders.
Medial border
The facial surface is concave from above downward, convex from side to side, and near the centre is perforated by a small foramen, which transmits a small tributary to the facial vein. The posterior or nasal surface, covered in the recent state by mucous membrane, is concave laterally, and traversed by a longitudinal groove [sulcus ethmoidalis] for the anterior ethmoidal branch of the ophthalmic division of the fifth nerve. The short superior border is thick and serrated for articulation with the medial part of the nasal notch of the frontal. The inferior border is thin, and serves for the attachment of the lateral nasal cartilage. It is notched for the external nasal branch of the anterior ethmoidal nerve. The nasal bones of the two sides are united by their medial borders, forming the internasal suture. The contiguous borders are prolonged backward to form a crest which rests on the frontal spine and the anterior border of the perpendicular plate of the ethmoid. The lateral border articulates with the frontal process of the maxilla.
Ossification. — Each nasal bone is developed from a single centre which appears about the eighth week in the membrane overlying the fronto-nasal cartilage. The cartilage, which is continuous with the ethmoid cartilage above and the lateral cartilage of the nose below, subsequently undergoes absorption as a result of the pressure caused by the expanding bone. A.t birth the nasal bones are nearly as wide as they are long, whereas in the adult the length is three times greater than the width.
THE MAXILLA
The maxilla or upper jaw-bone (figs. 109, 110, 111) is one of the largest and most important of the bones of the face. It supports the maxillary teeth and takes part in the formation of the orbit, the hard palate, and the nasal fossa. It is divisible into a body and four processes, of which two — the frontal and zygomatic — belong to the upper part, and the palatine and alveolar to the lower part of the bone.
The body is somewhat pyramidal in shape and hollowed by a large cavity known as the sinus maxillaris (antrum of Highmore) , lined by mucous membrane in the recent state, and opening at the base of the pyramid into the nasal cavity, the zygomatic process forming the apex. The anterior (or facial) surface looks forward and outward and is marked at its lower part by a series of eminences which indicate the positions of the fangs of the teeth. The eminence produced by the fang of the canine tooth is very prominent and separates two fossa. That on the medial side is the incisive fossa, and gives origin to the alar and transverse portions of the nasalis, and just above the socket of the lateral incisor tooth, to a slip of the orbicularis oris; on the lateral side is the canine fossa, from which the caninus {levator anguli oris) arises. Above the canine fossa, and close to the margin of the orbit, is the infra-orbital foramen, through which the terminal branches of the infra-orbital nerve and vessels emerge, and from the ridge immediately above the foramen the quadratus labii superioris takes origin. The medial margin of the anterior surface is deeply concave, forming the nasal notch, and is prolonged below into the anterior nasal spine.
A ridge of bone extending upward from the socket of the first molar tooth separates the anterior from the infratemporal (zygomatic) surface. This latter surface is convex and presents near the middle the orifices of the posterior alveolar canals, transmitting the posterior alveolar vessels and nerves. The posterior inferior angle, known as the tuberosity [tuber maxillare], is rough and is most prominent after eruption of the wisdom tooth. It gives attachment to a few fibres of the internal pterygoid muscle and articulates with the tuberosity of the palate.
forms the greater part of the floor of the orbit.
Anteriorly, it is rounded and reaches the orbital circumference for a short distance at the root of^the nasal process; lateraUy is the rough surface for the zygomatic bone. The posterior border, smooth and rounded, forms the inferior boundary of the inferior orbital fissure. The medial border is nearly straight and presents behind the frontal process, a smooth rounded angle forming part of the circumference of the orbital orifice of the naso-lacrimal canal, and a notch which receives the lacrimal bone. The rest of the medial border is rough for articulation with the lamina papyracea of the ethmoid and orbital process of the palate bone.
The orbital surface is traversed by the infra-orbital groove, which, commencing at the posterior border, deepens as it passes forward and finally becomes closed in to form the infra-orbital canal. It transmits the second division of the fifth nerve and the infra-orbital vessels and terminates on the anterior surface immediately below the margin of the orbit. From the infra-orbital, other canals — the anterior and middle alveolar — run downward in the wall of the antrum and transmit the anterior and middle alveolar vessels and nerves. Lateral to the commencement of the lacrimal canal is a shallow depression for the origin of the inferior oblique.
The nasal surface takes part in the formation of the lateral wall of the nasal fossa. It presents a large irregular aperture which leads into the antrum and, immediately in front of this, the lacrimal groove, directed downward, backward, and laterally into the inferior meatus of the nose. The groove is converted
lacrimal duct.
In front of the groove is a smooth surface crossed obhquely by a ridge, the concbal crest, for articulation with the inferior nasal concha. The surface below the crest is smooth, concave, and belongs to the inferior meatus; the surface above the crest extends on to the lower part of the frontal process and forms the wall of the atrium of the middle meatus. Behind the opening of the antrum the surface is rough for articulation with the vertical plate of the palate bone, and crossing it obliquely is a smooth groove converted by the ipalate into the pterygopalatine canal for the passage of the (descending) palatine nerves and the descending palatine artery.
The frontal process, somewhat triangular in shape, rises vertically from the angle of the maxilla. Its lateral surface is continuous with the anterior surface of the body, and gives attachment to the orbicularis oculi, the medial palpebral ligament and the quadratus labii superioris {caput angular e). The medial surface forms part of the lateral boundary of the nasal fossa and is crossed obliquely by a low ridge, known as the agger nasi, limiting the atrium of the middle meatus.
The hinder part of this surface rests on the anterior extremity of the labyrinth of the ethmoid and completes the maxillo-ethmoidal cells. The superior border articulates with the frontal; the anterior border articulates with the nasal bone; the posterior border is thick and vertically grooved, in continuation with the lacrimal groove, and lodges the lacrimal sac. The medial margin of the groove articulates with the lacrimal bone, and the junction of its lateral margin with the orbital surface is indicated by the lacrimal tubercle.
The zygomatic process, rough and triangular, forms the summit of the prominent ridge of bone separating the anterior and infratemporal surfaces. It articulates above with the zygomatic, and from its inferior angle a few fibres of the masseter take origin. The anterior and posterior surfaces are continuous with the anterior and infratemporal surfaces of the body.
The palatine process projects horizontally from the medial surface and, with the corresponding process of the opposite side, forms about three-fourths of the hard palate. The superior surface is smooth, concave from side to side, and
constitutes the larger part of the floor of the nasal fossa. The inferior surface is vaulted, rough, and perforated with foramina for nutrient vessels. Near its lateral margin is a longitudinal groove for the transmission of the vessels and nerves which issue at the posterior palatine canal and course along the lower aspect of the palate. When the bones of the two sides are placed in apposition, a large orifice may be seen in the middle line immediately behind the incisor teeth. This is the incisive foramen, at the bottom of whjch are four foramina. Two are small and arranged one behind the other exactly in the meso-palatine suture. These are the foramina of Scarpa and transmit the naso-palatine nerves, the left
passing through the anterior and the right through the posterior aperture. The lateral and larger orifices are the foramina of Stenson, representing the lower apertures of two passages by which the nose communicates with the mouth ; they transmit some terminal branches of the descending palatine artery to the nasal fossae, and lodge recesses of the nasal mucous membrane and remnants of Jacobson's organs.
Running laterally from the incisive foramen to the space between the second incisor and canine tooth, an indistinct suture may sometimes be seen, indicating the hne of junction of the maxillary and pre-maxillary portions of the bone. The premaxilla or incisive bone is the part which bears the incisor teeth and in some animals exists tliroughout life as an independent element. The posterior border of the palate process is rough and serrated for articulation with
the horizontal plate of the palate bone which completes the hard palate. The medial border joins with its fellow to form the nasal crest upon wliich the vomer is received. The more elevated anterior portion of this border is known as the incisor crest, and is continued forward into the anterior nasal spine. The septal cartilage of the nose rests on its summit and the anterior extremity of the vomer lies immediately behind it. At the side of the incisor crest is seen the upper aperture of the canal leading from the nose to the mouth (Stenson's canal), which in its course downward becomes a groove by a deficiency of its medial wall. Thus when the two bones are articulated a canal is formed (incisive) with the lower ends of two canals opening into it.
there are eight tooth-cavities (alveoli), with wide mouths, gradually narrowing as they pass into the substance of the bone, and forming exact impressions of the corresponding fangs of the teeth. The pit for the canine tooth is the deepest; those for the molars are the widest, and present subdivisions. Along the lateral aspect of the alveolar process the buccinator arises as far forward as the first molar tooth.
The maxillary sinus or antrtma of Highmore, as the air-chamber occupying the body of the bone is called, is somewhat pyramidal in shape, the base being represented by the nasal or medial surface, and the apex corresponding to the zygomatic process. In addition it has four walls: the superior is formed by the orbital plate, and the inferior by the alveolar ridge. The anterior wall corresponds to the anterior surface of the maxilla, and the posterior is formed by the infratemporal surface. The medial boundary or base presents a very irregular
orifice at its posterior part; this is partially filled in by the vertical plate of the palate bone, the uncinate process of the ethmoid, the maxillary process of the inferior nasal concha, and a small portion of the lacr'mal bone. Even when these bones are in their relative positions, the orifice is very irregular in shape, and requires the mucous membrane to form the definite rounded aperture (or apertures, for they are often multiple) known as the opening of the sinus through which the cavity communicates with the middle meatus of the nose.
The cavity of the sinus varies considerably in size and shape. In the young, it is small and the walls are thick: as life advances it enlarges at the expense of its walls, and in old age they are often extremely thin, so that occasionally the cavity extends even into the substance of the zygomatic bone. The floor of the sinus is usually very uneven, due to prominences corresponding to the roots of the molar teeth. In most oases the bone separating the teeth from the sinus is very thin, and in some cases the roots project into it. The teeth which come into closest relationship with the sinus are the first and second molars, but the sockets of any of the teeth lodged in the maxilla may, under diseased conditions, communicate with it. As a rule, the cavity of the sinus is single, but occasionally specimens are seen in which it is divided by bony septa into chambers, and it is not uncommon to find recesses separated by bony processes. The roof of the sinus presents near its anterior aspect what appears to be a thick rib of bone; this is hollow and corresponds to the infra-orbital canal.
Blood-supply. — The maxilla is a very vascular bone and its arteries are numerous and large. They are derived from the infra-orbital, alveolar, descending palatine, spheno-palatine, ethmoidal, frontal, nasal, and facial vessels.
Articulations. — With the frontal, nasal, lacrimal, ethmoid, palate, vomer, zygomatic, inferior nasal concha and its fellow of the opposite side. Occasionally it articulates with the great wing, and the pterygoid process, of the sphenoid.
THE PALATE BONE
Ossification. — The maxilla is developed from several centres which are deposited in membrane during the second month of intrauterine life. Several pieces are formed which speedily fuse, so that at birth, with the exception of the incisor fissure separating the maxilla from the premaxiUa, there is no trace of the composite character of the bone. The centres of ossification comprise — (1) the malar, which gives rise to the portion of bone outside the infra-orbital canal;
(3) the palatine, forming the hinder three-fourths of the palatal process and adjoining part of the nasal wall; (-1) the premaxiilary, giving rise to the independent premaxiUary bone (os incisivum), which lodges the incisor teeth and completes the anterior fourth of the hard palate. In the early stages of growth the premaxiUa may consist of two pieces arising from two centres of ossification which AJbrecht has named as follows: — the endognathion, or medial division for
the central incisor, and the mesognathion, or lateral division for the lateral incisor; the rest of the maxilla is named the exognathion; (5) the prepalatine, corresponding to the infra-vomerine centre of Rambaud and Renault, forms a portion of bone interposed between the premaxiUary in front and the palatine process behind. It gives rise to a part of the nasal surface and completes the medial waU of the incisive canal.
At birth the sinus is narrow from side to side and does not extend laterally to any appreciable extent between the orbit and the alveoli of the teeth. During the early years of life it graduaUy enlarges, but does not attain its fuU growth untU after the period of the second dentition.
The palate bone [os palatinum] (figs. 115, 116) forms the posterior part of the hard palate, the medial wall of the nasal fossa between the maxilla and the medial pterygoid plate, and, by its orbital process, the hinder part of the floor of the orbit. It is somewhat L-shaped and presents for examination a horizontal part and a perpendicular part; at their point of junction is the pyramidal process, and surmounting the top of the vertical plate are the orbital and sphenoidal processes, separated by the spheno-palatine notch.
The horizontal part resembles the palatine process ofthe maxilla, but is much shorter. The superior surface is smooth, concave from side to side, and forms the back part of the floor of the nasal fossa; the inferior surface completes the hard palate behind and presents near its prosterior border a transverse ridge which gives attachment to the tensor veli 'palatini muscle.
The anterior border is rough for articulation with the palatine process of the maxiUa; the posterior is free, curved, and sharp, giving attachment to the soft palate. MediaUy it is thick and broad for articulation with its fellow of the opposite side, forming a continuation of the crest of the palatal processes of the maxiUae and supporting the vomer. The posterior extremity of the crest is the posterior nasal spine, from which the azygos uvulce arises. LateraUy, at its junction with the perpendicular part, it is grooved by the lower end of the pterygo-palatine canal.
a vertical groove which forms with the maxilla the pterygo -palatine canal for the transmission of the anterior palatine nerve and the descending palatine artery. The part of the surface in front of the groove articulates with the nasal surface of the maxilla and overlaps the orifice of the antrum by the maxillary process, a variable projection on the anterior border. Behind the groove the surface is rough for articulation with the maxilla below and the medial pterygoid plate above.
Inferior meatus
The medial or nasal surface presents two nearly horizontal ridges separating three shallow depressions. Of the depressions, the lower forms part of the inferior meatus of the nose, and the limiting ridge or conchal (inferior turbinate) crest articulates with the inferior nasal concha. Above this is the depression forming part of the middle meatus, and the ridge or ethmoidal (superior turbinate) crest, constituting its upper boundary, articulates with the middle nasal concha.
The upper groove is narrower and deeper than the other two and forms a large part of the superior meatus of the nose. The anterior border of the vertical plate is thin and bears the maxillary process, a tongue-like piece of bone, which e.xtends over the opening of the maxillary sinus from behind. This border is continuous above with the orbital process. The posterior border is rough and articulates with the anterior border of the medial pterygoid plate. It is continuous superiorly with the sphenoidal process.
The pyramidal process or tuberosity fits into the notch between the lower extremities of the pterygoid plates and presents posteriorly three grooves. The middle, smooth and concave, completes the pterygoid fossa, and gives origin to a few fibres of the internal -pterygoid; the medial and lateral grooves are rough for articulation with the anterior border of the corresponding pterygoid plate. Inferiorly, close to its junction with the horizontal plate, are the openings of the greater palatine and smaller palatine canals, of which the latter are the smaller and less constant; they transmit the palatine nerves. Medially the pyramidal process gives origin to a few fibres of the superior constrictor of the pharynx, and laterally a small part appears in the zygomatic fossa between the tuberosity of the maxilla and the pterj'goid process of the sphenoid.
The sphenoidal process, the smaller of the two processes surmounting the vertical part, curves upward and medially and presents three surfaces and two borders. The superior surface is in contact with the body of the sphenoid, and the top of the medial pterygoid plate, where it completes the pharyngeal canal. The medial or inferior surface forms part of the lateral
THE ZYGOMATIC BONE 93
wall and roof of the nasal fossa, and at its medial end tounhes the ala of the vomer. The lateral surface looks forward and laterally into the pterygo-palatine (spheno-maxillary) fossa. Of the two border3,the posterior is thin and articulates with the medial pterygoid plate; the anterior border forms the posterior boundary of the spheno-palatine foramen.
The orbital process is somewhat pyramidal in shape, and presents for examination five surfaces, three of which — the posterior, anterior, and medial — are articular and the rest nonarticular. The posterior or sphenoidal surface is small and joins the anterior surface of the body of the sphenoid; the medial or ethmoidal articulates with the labyrinth of the ethmoid; and the anterior or maxillary, which is continuous with the lateral surface of the perpendicular part, is joined with the maxilla. Of the two non-articular surfaces, the superior or orbital, directed upward and laterally, is slightly concave, and forms the posterior angle of the floor of the orbit; the lateral or zygomatic, smooth and directed lateral, looks into the pterygopalatine (spheno-maxillary) and zygomatic fossse, and forms the anterior boundary of the spheno-palatine foramen. The process is usually hollow and the cavity completes one of the posterior ethmoidal cells or communicates with the sphenoidal sinus.
Fig. 117. — Maxilla and Palate Bones showing how the Inpha-okbital Groove Runs Outwakd almost at Right Angles phom the Neighbourhood op the Sphenopalatine Foramen on the Back of the Maxilla and the Orbital Process op the Palate. Posterior View. (E. Fawcett.)
Between the orbital and sphenoidal processes is the spheno-palatine notch, converted by the body of the sphenoid, into a complete foramen. It leads from the pterygo-palatine fossa into the back part of the nasal cavity close to its roof, and transmits the medial branches from the spheno-palatine ganglion and the spheno-palatine vessels.
fellow of the opposite side.
Ossification. — The palate is ossified in membrane from a single centre which appears about the eighth week at the angle between the horizontal and perpendicular parts. At birth the two parts are nearly equal in length, but as the nasal fossae increase in vertical depth, the perpendicular part is lengthened until it becomes about twice as long as the horizontal part.
The zygomatic [os zygomaticum] or malar bone (fig. 118) forms the prominence known as the cheek and joins the zygomatic process of the temporal with the maxilla. It is quadrangular in form with the angles directed vertically and horizontally. The malar (or external) surface is convex and presents one or two small orifices for the transmission of the zygomatico-facial nerves and vessels. It is largely covered by the orbicularis oculi and near the middle is slightly elevated to form the malar tuberosity, which gives origin to the zygomaticus and zygomatic head of quadrate muscle of upper lip.
of bone, the orbital process, which forms the anterior boundary of the temporal fossa. The upper part gives origin to a few fibres of the temporal muscle, while at the lower part is a large rough area for articulation with the zygomatic process of the maxilla.
Malar tubercle
surface of the process are seen the foramina of two zygomatico -orbital canals, which transmit the zygomatico-facial and zygomatico-temporal branches of the zygomatic branch of the fifth, together with two small arteries from the lacrimal. In some cases, however, the canal is single at its commencement on the orbital plate and bifurcates as it traverses the bone. The rough free edge of the
process articulates above with the zygomatic border of the great wing of the sphenoid, and below with the maxilla. When the orbital process is large, it excludes the great wing of the sphenoid from articulation with the maxilla, and the border then presents near the middle a short, non-serrated portion
fissure.
All the four angles of the zygomatic bone have distinguishing featm-es. The superior, forming the fronto-sphenoidal process, is the most prominent, and is serrated for articulation with the zygomatic process of the frontal; the anterior or infra-orbital process, sharp and pointed, articulates with the maxilla and occasionally forms the superior boundary of the infraorbital foramen; the posterior or temporal process is blunt and serrated rnainly on its medial aspect for articulation with the zygomatic process of the temporal; the inferior angle, blunt and rounded, is known as the malar tubercle.
Of the four borders, the orbital is the longest and extends from the fronto-sphenoidal to the infra-orbital process. It is thick, rounded, and forms more than one-third of the circumference of the orbit; the temporal border, extending from the fronto-sphenoidal to the temporal process, is sinuously curved and gives attachment to the temporal fascia. Near the frontal .angle is usually seen a sHght elevation, the processus marginalis, to which a strong shp of the fascia is attached; the masseteric border, thick and rough, completes the lower edge of the zygomatic arch and gives origin to the anterior fibres of the masseler; the maxillary border, rough and eoncave, is connected by suture with the maxilla, and near the margin of the orbit gives origin to the infra-orbital head of the guadratus Inbii svperioris.
Ossification. — The zygomatic is ossified in membrane from three centres which appear in the eighth week of intra-uterine life. The three pieces, which have received the names of ■previolar, poslmalar, and hypnmalar, unite .about the fifth month. Occasionally the primary nuclei fail to coalesce, and the bone is then represented in the adult by two or three portions separated by sutures. In those cases in which the premalar and postmalar unite and the hypomalar remains distinct, the suture is horizontal; if the independent portion is the premalar, then the suture is vertical. The bipartite zygomatic has been observed in skulls obtained from at least a dozen different races of mankind, but because of the greater frequency in which it occurs in the crania of the Japanese (seven per cent.), the name of o.« Japonicum has been given to it.
THE MANDIBLE
The mandible [mandibula] or lower jaw-bone (figs. 120, 121) is the largest and strongest bone of the face. It supports the mandibular teeth, and by means of a pair of condyles, moves on the skull at the mandibular fossse of the temporal bones. It consists of a horizontal portion — the body- — strongly curved, so as to somewhat resemble in shape a horseshoe, from the ends of which two branches or rami ascend almost at right angles.
The body is marked in the middle line in front by a faint groove which indicates the symphysis or place of union of the two originally separate halves of the bone. This ends below in the elevation of the chin known as the mental protuberance, the lowest part of which is slightly depressed in the centre and raised on each side to form the mental tubercle. Each half of the mandible presents two surfaces and two borders. On the lateral surface, at the side of the symphysis, and below the incisor teeth, is a shallow depression, the incisor fossa, from which the vientalis and the incisivus labii inferioris muscle arise; and more laterally, opposite the second bicuspid tooth, and midway between the upper and lower margins, is the mental foramen, which transmits the mental nerve and vessels. Below the foramen is the oblique line, extending backward and upward from the mental tubercle to the anterior border of the rairius; it divides the body into an upper or alveolar part and a lower or basilar part, and affords attachment to the quadratus labii inferioris and the triangularis oris.
The medial surface presents at the back of the symphysis four small projections, called the mental spine (genial tubercles). These are usually arranged in two pairs, one above the other; the upper comprising a pair of prominent spines, gives origin to the genio-glossi, and the lower, represented in some bones by a median ridge or only a slight roughness, gives origin to the genio-hyoid muscles. At the side of the symphysis near the inferior margin is an oval depression, the digastric fossa, for the insertion of the digastric muscle. Commencing below the mental spine, and extending upward and backward to the ramus, is the mylo-hyoid line, which becomes more prominent as it approaches ,the alveolar border; it gives attachment along its whole length to the mylo-hyoid muscle, at its posterior fifth to the superior constrictor of the pharynx, and at the posterior extremity to the pterygo-mandibular raphe. Above this line at the side of the symphysis is a smooth depression [fovea sublingualis] for the sublingual gland, and below it, farther back, is another for the submaxillary gland.
The alveolar part or superior border is hollowed out into eight sockets or alveoli. These are conical in shape and form an exact counterpart of the rootsof the teeth which they contain. From the lateral aspect of the alveolar process, as far forward as the first molar tooth, the buccinator muscle takes origin.
The base or inferior border is thick and rounded. In the anterior part of its extent it gives attachment to the platysma, and near its junction with the ramus is a groove for the external maxillary artery which here turns upward into the face.
The ramus is thinner than the body and quadrilateral in shape. The lateral surface is flat, gives insertion to the masseter, and at the lower part is marked by several oblique ridges for the attachment of tendinous bundles in the substance of the muscle. The medial surface presents near the middle the mandibular (inferior dental) foramen, leading into the mandibular (inferior dental) canal which traverses the bone and terminates at the mental foramen on the lateral surface of the body. From the canal, which in its posterior two-thirds is nearer to the medial, and in its anterior third nearer to the lateral, surface of the mandible,
External oblique line
a series of small channels pass upward to the sockets of the posterior teeth and transmit branches of the inferior alveolar (dental) vessels and nerve; in front of the mental foramen a continuation of the canal extends forward and conveys the vessels and nerves to the canine and incisor teeth. The mandibular foramen is bounded medially by a sharp margin forming the lingula (mandibular spine), which gives attachment to the spheno-mandibular ligament.
The posterior margin of the. lingula is notched. This notch forms the commencement of a groove, the mylo-hyoid groove [sulcus mylohyoideus], which runs obliquely downward and forward and lodges the mylo-hyoid nerve and artery, and, in the embryo, Meckel's cartilage. Behind the spine is a rough area for the insertion of the internal pterygoid muscle.
The posterior border of the ramus is thick and rounded, and in meeting the inferior border of the ramus forms the angle of the jaw, which is rough, obtuse, usually everted, and about 122° in the adult; the angle gives attachment to the stylo-mandibular ligament. The inferior border is thick, rounded, and continuous with the base. The anterior border is continuous with the oblique line, whilst the upper border presents two processes separated by a deep concavity, the mandibular (sigmoid) notch. Of the processes, the anterior is the coronoid; the posterior, the condylar.
The condylar process consists of the condyle [capitulum mandibulse] and the narrowed portion by which it is supported, the neck. The condyle is oval in shape, with its long axis transverse to the upper border of the ramus, but oblique with regard to the median axis of the sicull, so that the lateral extremity, which presents the condylar tubercle for the temporo-mandibular ligament of the temporo-mandibular articulation, is a little more forward than the medial extremity. The convex surface of the condyle is covered with cartilage in the recent
state, and rests in the mandibular fossa; the neck is flattened from before backward, and presents, in front, a depression [fovea pterygoidea] for the insertion of the external pterygoid muscle.
The coronoid process, flattened and triangular, is continued upward from the anterior part of the ramus. The lateral surface is smooth and gives insertion to the temporal and masseter muscles; the medial surface is marked by a ridge which descends from the tip and becomes continuous with the posterior part of the mylo-hyoid line. On the medial surface, as well as on the tip of the coronoid
panicus
process, the temporal muscle is inserted. The mandibular notch, the deep semilunar excavation separating the coronoid from the condylar process, is crossed by the masseteric nerve and vessels.
Blood-supply. — Compared with other bones, the superficial parts of the mandible are not so freely supplied with blood. The chief artery is the inferior alveolar which runs in the mandibular canal, and hence, as the bone is exposed to injury and sometimes actually laid bare in its alveolar portion, it often necroses, especially if the artery is involved at the same time.
Ossification. — The mandible is mainly formed by ossification in the fibrous tissue investing the cartilage of the first branchial arch or Meckel's cartilage, although a small portion of the cartilage itself is directly converted into bone.
It is now generally admitted that the lower jaw is developed in membrane as a single skeletal element. The centre of ossification appears in the outer aspect of Meckel's cartilage and gives rise to the bony plate known as the dentary. This plate extends forward right up to the middle line in front, and from it a shelf grows upward for the support of the tooth germs.
Meckel's cartilage lies below and medial to the dentary plate, and the inferior alveolar nerve passes forward between the two structures. Meckel's cartilage itself takes some small part in the formation of the lower jaw. Ossification from the primary nucleus invades the cartilage at a point opposite the interval between the first and second tooth germs, and the resulting bone contributes to the formation of the alveolar margin opposite these two teeth. Behind this point the cartilage atrophies except in so far as it helps to form the spheno-mandibular ligament and the malleus and incus. Behind the symphysis the anterior extremity of the cartilage does not enter into the formation of the jaw, but it usually persists throughout foetal
THE Mandible and Maxilla
life as one or two small, rounded, cartilaginous masses. Occasionally they become ossified and give rise to accessory ossicles in this situation. The lamella of bone situated on the medial side of Meckel's cartilage, corresponding to the distinct splenial element in some animals, arises in man as an extension from the dentary element.
In connection with the condylar and coronoid processes, cartilaginous masses are developed. These do not, however, indicate separate elements, but are adaptations to the growth of the lower jaw. 'They are ossified by an extension from the surrounding membrane bone.
eighth week, and proceeds rapidly, so that by the fourth month the various parts are formed.
Age-changes. — At birth the mandible is represented by two nearly horizontal troughs of bone, lodging unerilpted teeth, and joined at the symphysis by fibrous tissue. The body is mainly alveolar, the basal part being but little developed; the condyle and the upper edge of the symphysis are nearly on a level; the mental foramen is nearer the lower than the upper margin, and the angle is about 175°. The inferior alveolar nerve lies in a shallow groove between the spleuial and dentary plates.
During the first year osseous union of the two halves takes place from below upward, but is not complete until the second year. After the first dentition, the ramus forms with the body of the mandible an angle of about 140°, and the mental foramen is situated midway between the upper and lower borders of the bone opposite the second milk-molar. In the adult, the angle formed by the ramus and body is nearer to a right angle, and the mental foramen is opposite the second bicuspid, so that its relative position remains unaltered after the first dentition. In old age, after the fall of the teeth, the alveolar margin is absorbed, the angle formed by the ramus and body is again increased, and the mental foramen approaches the alveolar margin. In a young and vigorous adult the mandible is, with the exception of the petrous portion of the temporal, the densest bone in the skeleton; in old age it becomes exceedingly porous, and often so soft that it may easily be broken.
THE HYOID BONE
The hyoid bone [os hyoideum] or os linguae (fig. 125), situated in the anterior part of the neck between the chin and the thyreoid cartilage, supports the tongue and gives attachment to numerous muscles. It is suspended from the lower extremities of the styloid processes of the temporal bones by two slender bands known as the stylo-hyoid ligaments, and is divisible into a body and two pairs of processes, the greater and lesser cornua.
The body, constituting the central portion of the bone, is transversely placed and quadrilateral in form. It is compressed from before backward and lies obliquely so that the anterior surface looks upward and forward and the posterior surface in the opposite direction.
The anterior surface is convex and divided by a horizontal ridge into a superior and an inferior portion. Frequently it also presents a vertical ridge crossing the former at right angles, and just above the point of intersection is the glosso-hyal
process, the vestige of a well-developed process in this situation in the hyoid bone of some of the lower animals (reptiles and the horse). In this way four spaces or depressions for muscular attachments are marked off, two on either side of the middle line. The posterior surface is deeply concave and separated from the epiglottis by the thyreo-hyoid membrane, and by some loose areolar tissue. The membrane passes upward from the thyreoid cartilage to be attached to the superior border, and interposed between it and the concavit.y on the back of the body is a small synovial bursa. The inferior border, thicker than the upper, gives insertion to muscles. The lateral borders are partly in relation with the greater cornua, \vith which they are connected, up to middle life, by synchondrosis, but after this period, usually by bone.
The greater cornua projects upward and backward from the sides of the body. They are flattened from above downward, thicker near their origin, and terminate posteriorly in a rounded tubercle to which the thyreo-hyoid ligament is attached.
The lesser cornua are small conical processes projecting upward and backward opposite the lines of junction between the body and the greater cornua, and by their apices give attachment to the stylo-hyoid ligaments; they are connected to the body by fibrous tissue. Professor Parsons has shown that a joint with a synovial cavity is common between the smaller and geater cornua. The lesser cornua are sometimes partly or even completely cartilaginous in the adult.
Ossification. — In the early months of intra-uterine life the hyoid bone is composed of hyahne cartilage and is directly continuous with the styloid processes of the temporal bones. Ossification takes place from six centres, of which two appear in the central piece of cartilage, one on either side of the middle line, either just before or just after birth; soon after their appearance, however, they coalesce to form the body of the bone (basi-hyal). The centre for each of the greater cornua (thyreo-hyals) appears just about the time of birth, and for each of the lesser cornua (oerato-hyals) some years after birth, even as late as puberty. (F. G. Parsons.) The greater cornua and the body unite in middle life; the lesser cornua rarely ankylose with the body and only in advanced age. Professor Parsons has shown, however, that the lesser cornua more frequently unite with the greater cornua.
THE SKULL AS A WHOLE
The skull, formed by the union of the cranial and facial bones already described, may now be considered as a whole. Taking a general view, it is spheroidal in shape, smooth above, compressed from side to side, flattened and uneven below, and divisible into six regions : a superior region or vertex, a posterior or occipital region, an anterior or frontal region, an inferior region or base, and two lateral regions.
Viewed from above {norma verticalis) the skull presents an oval outline with the broader end behind, and includes the frontal, parietals, and the interparietal portion of the occipital. In a skull of average width the zygomatic arches are visible, but in very broad skulls they are obscured.
The metopic, which is, in most skulls, merely a median fissure in the frontal bone just above the glabella; occasionally it involves the whole length of the bone. It is due to the persistence of the fissure normally separating the two halves of the bone in the infant.
Viewed from behind {norma occipitalis) the skull is somewhat pentagonal in form. Of the five angles, the superior or median is situated in the line of the sagittal suture; the two upper lateral angles coincide with the parietal eminences and the two lower with the mastoid processes of the temporal bones. Of the sides, four are somewhat rounded, and one, forming the basal line, running between the mastoid processes, is flattened.
The centre is occupied by the lambda, and radiating from this point are three sutures, the sagittal, and the two parts of the lambdoid. Each half of the lambdoid suture bifurcates at the mastoid portion of the temporal bone, the two divisions constituting the parieto-mastoid and occipito-mastoid sutures; the point of bifurcation is known as the asterion.
In the lower part of the view is seen the external occipital protuberance (inion), the occipital crest, and the thi-ee pairs of nuchal lines, which give it a rough and uneven appearance. The occipital point is the point of the occiput furthest from the glabella in the median plane. It is situated above the external occipital protuberance.
The lateral region (norma lateralis) (fig. 127) is somewhat triangular in shape, being bounded above by a line extending from the zygomatic process of the frontal, along the temporal line to the lateral extremity of the superior nuchal line of the occipital bone; this forms the base of the triangle. The two sides are represented by lines drawn from the extremities of the base to the angle of the jaw. It is divisible into two portions, one in front, the other behind, the eminentia articularis [tuberculum articulare]. The posterior portion presents, in a horizontal line from behind forward, the mastoid portion of the temporal, with its process and foramen, the external auditory meatus, the centre of which is known as the atiricular point, the mandibular fossa, and the condyle of the mandible.
In the anterior portion are three fossaj, (a) temporal, (b) infratemporal, (c) pterygo-palatine (spheno-maxillary), and two fissures, the inferior orbital (sphenomaxillary) and pterygo-palatine.
(a) The temporal fossa, somewhat semilunar in shape, is bounded above and behind by the temporal line, in front by the frontal, zygomatic, and great wing of sphenoid, and laterally by the zygomatic arch, by which it is separated superficially from the infratemporal fossa; more deeply the infratemporal ridge separates the two fossae.
The fossa is formed by parts of five bones, the zygomatic, temporal, parietal, frontal, great wing of sphenoid, and is traversed by six sutures, coronal, spheno-zygomatic, sphcnosc(uamosal, spheno-parietal, squamosal, and spheno-frontal. The point where the temporal ridge is crossed by the coronal suture is the stephanion, and the region where the frontal, sphenoid, temporal, and parietal meet is the pterion. The latter is frequently occupied in the adult by the epipteric bone.
the muscle.
(b) The infratemporal fossa (zygomatic fossa), irregular in shape, is situated below and to the medial side of the zj'goma, covered in part by the ramus of the mandible. It is bounded in front by the lower part of the medial surface of the zygomatic, and by the infratemporal surface of the maxilla, on which are seen the orifices of the posterior superior alveolar canals; behind by the posterior border of the lateral pterygoid plate, the spine of the sphenoid, and the articular tubercle; above by the infratemporal ridge, a small part of the squamous portion of
the temporal, the great wing of the sphenoid perforated by the foramen ovale and foramen spinosum; helow by the alveolar border of the maxilla; laterally by the ramus of the mandible and the zygoma formed by zygomatic and temporal; medially by the lateral pterygoid plate, a line from which to the spine of the sphenoid separates the infratemporal fossa from the base of the skull. It contains the lower part of the temporal muscle and the coronoid process of the mandible, the external and internal pterygoids, the internal maxillary vessels, and the mandibular division of the fifth nerve with numerous branches. At its upper and medial part are seen the inferior orbital and pterygo-palatine fissures.
The inferior orbital (or spheno-maxillary) fissure is horizontal in position, and lies between the maxQla and the great wing of the sphenoid; laterally it is usually completed by the zygomatic, though in some cases the sphenoid joins the maxilla, and in this way excludes the zygomatic bone from the fissure; medially it is terminated by the infratemporal surface of the orbital process of the palate bone. Through this fissure the orbit communicates with the pterygopalatine (spheno-maxillary), infratemporal, and temporal fossae. It transmits the infraorbital nerve and vessels, the zygomatic nerve, ascending branches from the spheno-palatine ganglion to the orbit, and a communicating vein from the ophthalmic to the pterygoid plexus.
The pterygo-palatine (pterygo-maxillary) fissure forms a right angle with the inferior orbital fissure and is situated between the maxilla and the anterior border of the pterygoid process of the sphenoid. At its lower angle, where the two lips of the fissure approximate, the lateral pterj'goid plate occasionally articulates with the maxilla, but they are usually separated by' a thin portion of the pyramidal process of the palate. The pterygo-palatine fissure, which serves to connect the infratemporal fossa with the pterygo-palatine fossa, is bounded medially by the perpendicular part of the palate; it transmits branches of the internal maxillary artery, and the corresponding veins, to and from the pterygo-palatine fossa.
(c) The pterygo-palatine (spheno-maxillary) fossa is a small space, of the form of an inverted pyramid, situated at the angle of junction of the inferior orbital (spheno-maxillary) with the pterygo-palatine (pterygo-maxillary) fissure, below the apex of the orbit. It is bounded infroid by the infratemporal surface of the maxilla; behind, by the base of the pterygoid process and the lower part of the anterior surface of the great wing of the sphenoid; medially by the perpendicular part of the palate with its orbital and sphenoidal processes; above by the lower surface of the body of the sphenoid. Three fissures terminate in it — viz., the superior orbital, pterygo-palatine, and inferior orbital; through the superior orbital fissuje it communicates with the cranium, through the pterygo-palatine fissure with the infratemporal fossa, through the inferior orbital fissure with the orbit, and throagh the spheno-palatine foramen on the medial wall it communicates with the upper and back part of the nasal fossa. In-
eluding the spheno-palatine foramen sL\ foramina open into the fossa. Of these, three are on the posterior wall: enumerated from without inward, and from above downward, they are the foramen rotundum, the pterygoid (Vidian) canal, and the pharyngeal (pterygo-palatine) canal. The apex of the pyramid leads below into the pterygo-palatine canal and the accessory palatine canals which branch from it; and anteriorly is the orifice of the infra-orbital canal. The fossa contains the spheno-palatine ganglion, the maxillary nerve, and the terminal part of the internal maxillary artery, and the various foramina and canals in relation with the fossa serve for the transmission of the numerous branches which these vessels and nerves give off.
The external base of the skull {norma basilaris) (figs. 130, 131) extends from the incisor teeth to the occipital protuberance, and is bounded on each side by the alveolar arch, the zygomatic, the zygoma, the temporal, and the superior nuchal line of the occipital bone. It is very uneven and, excluding the lower jaw, divisible into three portions: (a) anterior, (b) middle or subcranial, and (c) posterior or suboccipital.
When the skull is inverted, the hard palate stands at a higher level than the rest, and is bounded anteriorly and laterally by the alveolar ridges containing the teeth. The bones appearing in the intermediate space are the premaxillary and palatine portions of the maxillse and the horizontal parts of the palate bones.
They are rough for the attachment of the muco-periosteum, and near the posterior margin is the ridge for the fibrous expansion of the tensor veli 'palatini. The following points are readily recognised (fig. 129) : —
Orbicularis oris
Scarpa, situated one behind the other in the meso-palatine suture; and two larger openings, the foramina of Stenson. The foramina of Scarpa transmit the naso-palatine nerves, and those of Stenson are in relation (embryonic) with the organs of Jacobson.
At the posterior angles of the hard palate are the greater palatine foramina, through which the descending palatine vessels and the anterior palatine nerves emerge on to the palate; a thin lip of bone separates them from the lesser palatine foramen in the tuberosity of the palate bone on each side, for the posterior palatine nerve.
palate.
At the posterior extremity of each alveolar ridge is the tuberosity of the maxilla, and between it and the palate bone is a foramen (variable in size and sometimes absent), the middle palatine foramen, for the middle palatine nerve. This foramen is often included under the lesser palatine foramina (BNA).
Behind the hard palate are the choanae (posterior nares), separated from each other by the vomer. Each is bounded laterally by the medial pterygoid plate; below by the horizontal plate of the palate bone; above by the under surface of the body of the sphenoid, with the ala of the vomer and a portion of the sphenoidal process of the palate bone.
Lateral to the choanae there is on each side a vertical fossa lying between the pterygoid plates. It extends upward to the under surface of the great wings of the sphenoid; it is completed anteriorly by the coalescence of the pterygoid plates and below by the pyramidal process of the palate bone. It contains the following points of interest: —
If a line be drawn across the base of the skull from one preglenoid tubercle to the other, it will fall immediately behind the lateral pterygoid plate and bisect the foramen spinosum on each side. A second transverse line, drawn across the opisthion or posterior margin of the foramen magnum, will fall behind the mastoid processes. The space between these arbitrary lines may be called the subcranial region; that behind the second hne, the suboccipital region.
sphenoid. It is formed by the inferior surface of the basilar process of the occipital and the body of the sphenoid, the petrous portion of the temporal bone, a small piece of the squamosal portion, the posterior part of the great wing of the sphenoid, and the condylar portions of the occipital bone. It presents the following points for examination (Figs. 95, 131): —
The mandibular fossa with the petro-tympanic fissure. This lodges the anterior process of the malleus, the tympanic twig of the internal maxillary artery. A small passage beside it, the canal of Huguier, conducts the chorda tympani nerve from the tympanum.
The mastoid process with the digastric and occipital grooves.
(c) The suboccipital region is largely formed by the tabular portion of the occipital bone with its ridges and areas for muscular attachment. Laterally a small part of the mastoid portion of the temporal is seen, pierced by a small foramen, of variable size, the mastoid foramen, which transmits a vein from the transverse (lateral) sinus and a meningeal branch of the occipital artery.
The anterior region {norma facialis) (figs. 132, 133) comprises the anterior end of the cranium or forehead, and the skeleton of the face; also the cavities known as the orbits, formed by the junction of the two parts of this region, and the nasal fossae, situated on either side of the septum of the nose.
The upper part or forehead, narrowest between the temporal crests about half an inch above the zygomatic processes of the frontal, presents at this level the two transverse sulci ; above are the frontal eminences, below the superciliary arches, and still lower the supra-orbital margins, interrupted near their medial ends by the supra-orbital notches.
Below the forehead are the openings of the orbits, bounded laterally by the zygomatic bones constituting the prominences of the cheeks, and between them the bridge of the nose, formed by the nasal bones and the frontal processes of the maxillae. Below the nasal bones is the apertura piriformis or anterior nasal aperture, leading into the nasal fossse. The teeth form a conspicuous feature in this view of the skull, the outline of which is completed below by the mandible.
The bones entering into formation of the norma facialis are: — the frontal, nasals, lacrimals, orbital surfaces of the small and the great wings, and a portion of the body of the sphenoid, the laminas papjrraceoB of the ethmoids, the orbital processes of the palate bones, the zygomatics, maxillse, inferior nasal conchae, and the mandible.
The transverse sutiu-e (fig. 133) extends from one zygomatic process of the frontal to the other. The upper part of the suture is formed by the frontal bone; below are the zygomatic, great and small wings of the sphenoid, lamina papyracea, lacrimal, maxillary, and nasal bones. A portion of this complex suture, lying between the sphenoidal and frontal bones, appears in the anterior cranial fossa.
The glabella, a smooth space between the converging superciliary arches. The ophryon, the most anterior point of the metopic suture. The nasion, the middle of the naso-frontal sutui'e.
THE ORBITS
The orbits [orbitse] (fig. 134) are two cavities of pyramidal shape, with their bases directed forward and laterally and their apices backward and medially; their medial walls are nearly parallel, but their lateral walls diverge so as to be nearly at right angles to each other. Each cavity forms a socket for the eyeball and the muscles, nerves, and vessels associated with it.
Seven bones enter into formation of its walls, viz., the frontal, zygomatic, sphenoid, ethmoid, lacrimal, palate, and maxilla; but as three of these — the frontal, sphenoid, and ethmoid — are single median bones which form parts of each cavity, there are only eleven bones represented in the two orbits. Each orbit presents for examination four walls, a circumference or base, and an apex.
The superior wall or roof, vaulted and smooth, is formed mainly by the orbital plate of the frontal and is completed posteriorly by the small wing of the sphenoid. At the lateral angle it presents the lacrimal fossa for the lacrimal gland, and at the medial angle a depression or a spine for the puOey of the superior oblique muscle.
External pterygoid plate
The inferior wall or floor is directed upward and laterally and is not so large as the roof. It is formed by the orbital plate of the maxilla, the orbital process of the zygomatic, and the orbital process of the palate bone. At its medial angle it presents the naso-laorimal canal, and near this, a depression for the origin of the inferior oblique muscle. It is marked near the middle by a furrow for the infra-orbital artery and the second division of the fifth nerve, terminating anteriorly in the infra-orbital canal, through which the nerve and artery emerge on the face. Near the commencement of the canal a narrow passage, the anterior alveolar canal, runs forward and downward in the anterior wall of the antrum, transmitting nerves and vessels to the incisor and canine teeth.
The lateral wall, directed forward and medially, is formed by the orbital surface of the great wing of the sphenoid, and the zygomatic. Between it and the roof, near the apex, is the superior orbital (sphenoidal) fissure, by means of which the third, fourth, ophthalmic division of the fifth, and sixth nerves enter the orbit from the cranial cavity; it also transmits some filaments from the cavernous plexus of the sympathetic, the orbital branch of the middle meningeal artery, recurrent branches of the lacrimal artery, and an ophthalmic vein. The lower margin of the fissure presents near the middle a small tubercle, from which the inferior head of the lateral rectus muscle arises. Between the lateral wall and the floor, near the apex, is the inferior orbital (spheno-maxiUary) fissure, tlu-ough which the second division of the fifth and the infra-orbital vessels pass from the pterygo-palatine fossa to enter the infra-orbital groove. At the anterior margin of the fissure the sphenoid occasionally articulates with the maxilla, but
the two are usually separated by the orbital plate of the zygomatic, and on the latter are seen the orifices of the zygomatico-temporal and zygomatico-facial canals, which traverse the zygomatic bone. The commencement of the zygomatico-temporal canal is sometimes seen in the spheno-zygomatic sutm-e connecting the sphenoid and zygomatic bones.
The medial wall, narrow and nearly vertical, is formed from before backward by the frontal process of the maxilla, the lacrimal, the lamina papyracea of the ethmoid, and the body of the sphenoid. At the junction of the medial wall with the roof, and in the suture between the ethmoid and frontal, are seen the orifices of the anterior and posterior ethmoidal canals, the anterior, transmitting the anterior ethmoidal vessels and nerve; and the posterior, the posterior vessels and nerve. Anteriorly is the lacrimal groove for the lacrimal sac, and behind this the lacrimal crest, from which the tensor tarsi arises. The medial wall, which is the smallest of the four, is traversed by three vertical sutures: — one between the frontal process of the maxilla and the lacrimal, a second between lacrimal and lamina papyracea, and a third between the lamina papyracea and the sphenoid. Occasionally the sphenoidal concha appears in the orbit between the ethmoid and the body of the sphenoid.
The apex of each orbit corresponds to the optic foramen, a circular orifice which transmits the optic nerve and ophthalmic artery. The base or circumference is quadrilateral in form and is bounded by the frontal bone above, the frontal process of the maxilla and the medial angular process of the frontal on the medial side, the zygomatic bone and the zygomatic process of the frontal on the lateral side, and by the zygomatic and the body of the maxilla below. The following points may also be noted: — The suture between the zygomatic process of the frontal bone and the zygomatic; the supra-orbital notch (sometimes a complete foramen); the sutiu'e between the frontal bone and the frontal process of the maxilla; and in the lower segment, the zygomatico-maxillary suture.
The orbit communicates with the cranial cavity by the optic foramen and superior orbital fissure; with the nasal fossa, by means of the naso-lacrimal canal; with the zygomatic and ptery go-palatine fossae, by the inferior orbital fissure. In addition to these large openings, the orbit has five other foramina — the infra-orbital, zygomatico-orbital, and the anterior and posterior ethmoidal canals — opening into it or leading from it.
The following muscles arise within the orbit : — the four recti, the -tuperior oblique, and levator palpebrce superioris, near the apex; the inferior oblique on the floor of the orbit lateral to the naso-lacrimal canal; and the tensor tarsi from the lacrimal crest. The margins of the inferior orbital fissure give attachment to the orhitalis muscle.
The nasal fossae (figs. 135, 136) are two irregular cavities situated on each side of a median vertical septum. They open in front by the piriform aperture and communicate behind with the pharynx by the choanse. They are somewhat .
oblong in transverse section, and extend vertically from the anterior part of the base of the cranium above to the superior surface of the hard palate below. Their transverse extent is very limited, especially in the upper part. Each fossa presents for examination a roof, floor, medial and lateral walls, and communicates with the sinuses of the frontal, sphenoid, maxilla, and ethmoid bones.
THE NASAL FOSSAE
The roof is horizontal in the middle, but sloped downward in front and behind. The anterior slope is formed by the posterior surface of the nasal bone and the nasal process of the frontal; the horizontal portion corresponds to the cribriform plate of the ethmoid and the sphenoidal concha; the posterior slope is formed by the inferior surface of the body of the sphenoid, the ala of the vomer, and a small portion of the sphenoidal process of the palate. The sphenoidal sinus opens at the upper and back part of the roof into the spheno-ethmoidal recess, above the superior meatus.
The floor is concave from side to side, and in the transverse diameter wider than the roof. It is formed mainly by the palatine process of the maxilla and completed posteriorly by the horizontal part of the palate bone. Near its anterior extremity, close to the septum, is the incisive canal.
The septum or medial waO is formed by the perpendicular plate of the ethmoid, the vomer, the rostrum of the sphenoid, the crest of the nasal bones, the frontal spine, and the rnedian crest formed by the apposition of the palatine processes of the maxilte and the horizontal parts of the palate bones. The anterior border has a triangular outline limited above by the perpendicular plate of the ethmoid and below by the vomer, and in the recent state the deficiency is filled up by the septal cartilage of the nose. The posterior border is formed by the
pharyngeal edge of the vomer, which separates the two choanaj. The septum, which is usually deflected from the middle line to one side or the other, is occasionally perforated, and in some cases a strip of cartilage, continuous with the triangular cartilage, extends backward between the vomer and perpendicular plate of the ethmoid (posterior or sphenoidal process).
The lateral wall is the most extensive and the most comphcated on account of the formation of the meatuses of the nose. It is formed by the frontal process and the medial surface of the maxilla, the lacrimal, the superior and inferior conchse of the ethmoid, the inferior nasal concha, the vertical part of the palate bone, and the medial surface of the medial pterygoid plate. The three conchae, which project medially, overhang the three recesses known as the meatuses of the nose. The superior meatus, the shortest of the three, is situated between the superior and middle nasal conch®, and into it open the orifice of the posterior ethmoidal cells and the spheno-palatine foramen. The middle meatus lies between the middle and inferior conchse. At its fore part it communicates with the frontal sinus by means of the infundibulum, and near the middle with the maxillary sinus (antrum); the communication with the sinus is very irregular and sometimes represented by more than one opening (fig. 136). Two sets of ethmoidal cells — the middle and anterior — also open into the middle meatus, the anterior in common with the infundibulum, the middle on an elevation known as the bulla ethmoidalis. The inferior meatus, longer than either of the preceding, is situated between the inferior nasal concha and the floor of the fossa, and presents, near the anterior part, the lower orifice of the canal for the naso-lacrimal duct.
The nasal fossae open on the face by means of the apertura piriformis, a heart-shaped or piriform opening whose long axis is vertical and whose broad end is below. The orifice is bounded above by the lower borders of the nasal bones, laterally by the maxillae, inferiorly by the premaxillary portions of the maxiUae, and in the recent state the orifice is divided by the septal cartilage. Below, where the lateral margins slope inward to meet in the middle line, is the anterior nasal spine.
The choanae (posterior nares) are bounded superiorly by the alae of the vomer, the sphenoidal processes of the palate, and the inferior surface of the body of the sphenoid; laterally by the lateral pterygoid plates; and inferiorly by the posterior edge of the horizontal plates of the palate bones. They are separated from each other by the posterior border of the vomer.
Hamular process
by the infundibulum each fossa is in communication with the frontal and anterior ethmoidal cells; the posterior ethmoidal cells open into the superior meatuses and the sphenoidal sinuses into the recesses above; the spheno-palatine foramina connect them with the pterygo-palatine fossae, and by means of an irregular orifice in each lateral wall they communicate with the maxillary sinuses. The canals for the naso-lacrimal ducts connect them with the orbits,Jand the incisive canals with the oral cavity.
THE INTERIOR OF THE SKULL
In order to study the interior of the skull it is necessary to make sections in three directions — sagittal, coronal, and horizontal. This enables the student to examine the various points with facility, and displays the great proportion the brain cavity bears to the rest of the skull. The sagittal section (fig. 138) should be made slightly to one side of the median line, in order to preserve the nasal septum. The black line (fig. 138) drawn from the basion (anterior margin of the foramen magnum) to the gonion (the anterior extremity of the sphenoid) represents the basi-cranial axis ; whilst the line drawn from the gonion to the subnasal point lies in the basi-facial axis. These two axes form an angle termed the cranio -facial, which is useful in making comparative measurements of crania. A line prolonged vertically upward from the basion will strike the bregma. This is the basi-bregmatic axis, and gives the greatest height of the cranial cavity. A line drawn from the ophryon to the occipital point indicates the greatest length of the cranium.
Near its middle, the cranial cavity is encroached upon by the petrous portion of the temporal bone on each side; the walls are channelled vertically by narrow grooves for the middle and small meningeal vessels, and toward the base and at the vertex are broader furrows for the venous sinuses.
The coronal section is most instructive when made in the basi-bregmatic axis. The section will pass through the petrous poition on each side in such a way as to traverse the external auditory passage and expose the tympanum and vestibule, and will also partially traverse the internal auditory meatus. Such
a section will divide the parietal bones slightly posterior to the parietal eminences, and a line drawn transversely across the section at the mid-point will give the greatest transverse measurement of the cranial cavity. A skull divided in this way facilitates the examination of the parts about the choanse (posterior nares) .
The horizontal section (figs. 139, 140) of the skull should be made through a line extending from the ophiyon to the occipital point, passing laterally a few millimetres above the pterion on each side. It is of great advantage to study the various parts on the floor of the cranial cavity in a second skull in which the dura mater and its various processes have not been removed.
The Anterior Cranial Fossa. — The floor of this fossa is on a higher level than the rest of the cranial floor. It is formed by the horizontal plate of the frontal bone, the cribriform plate of the ethmoid, and the lesser wings of the
Ophryon
sphenoid, which meet and exclude the body of the sphenoid from the anterior fossa. The free margins of the lesser wings and the anterior margin of the optic groove mark the limits of this fossa posteriorly. The central portion is depressed on each side of the crista galli, presents the numerous apertures of the cribriform plate, and takes part in the formation of the roof of the nasal fossse; laterally, the floor of the anterior cranial fossa is convex; it forms the roof of the orbits, and is marked by irregular furrows. It supports the frontal lobes of the cerebrum. The sutures traversing the floor of the fossa are the fronto-ethmoidal, forming three sides of a rectangle, that portion of the transverse facial suture which traverses the roof of the orbit, and the ethmo-sphenoidal suture, the centre of which corresponds to the gonion. The other points of interest in the fossa are:^
The Middle Cranial Fossa, situated on a lower level than the anterior, consists of a central and two lateral portions. In front it is limited by the posterior borders of the lesser wings of the sphenoid and the anterior margin of the optic groove, behind by the dorsum sellse and the upper angle of the petrous portion of both temporal bones. Laterally it is bounded on each side by the squamous portion of the temporal, the great wing of the sphenoid, and the parietal bone, whilst the floor is formed by the body and great wings of the sphenoid and the anterior surface of the petrous portion of the temporals. It contains the following sutures: — spheno-parietal, petro-sphenoidal, squamo-sphenoidal, squamous, and a part of the transverse suture. The central portion of the fossa presents from before backward :
The fossa hypophyseos or sella turcica, with the middle clinoid processes, and grooves for the internal carotid arteries. The dorsum sellse, with the posterior clinoid processes, and notches for the sixth pair of cranial nerves.
Willis.
The lateral portions are of considerable depth and marked by numerous elevations and depressions corresponding to the convolutions of the temporal lobes of the brain, and by grooves for the branches of the middle and small meningeal vessels. The following foramina are seen on each side: —
The superior orbital (sphenoidal) fissure, leading into the orbit and transmitting the third, fom-th, three branches of the ophthalmic division of the fifth and sixth cranial nerves, some filaments from the cavernous plexus of the sympathetic, an ophthalmic vein, the orbital branch of the middle meningeal, and a recurrent branch of the lacrimal artery.
N. spinosus.
The foramen lacerum is the irregular aperture between the body and great wing of the sphenoid, and the apex of the petrous portion of the temporal. In the recent state it is closed below by a layer of fibro-cartilage which is perforated by the Vidian nerve, a meningeal branch of the ascending pharynge.<!l artery, and an emissary vein. The carotid canal opens on its lateral wall and the pterygoid (Vidian) canal in front.
The eminentia arcuata, formed by the superior semicircular canal.
Anterior and slightly lateral to the eminentia arcuata the bone is exceedingly thin and translucent, forming the roof of the tympanum (tegmen tympani). When the dura mater is in situ, the depression lodging the semilunar ganglion is converted into a foramen, traversed by the fifth nerve, and in the same way the notch on the side of the dorsum sellae is converted into a foramen for the sixth nerve. In many skulls the middle clinoid process is prolonged toward the anterior clinoid process, with which it may be joined to complete a foramen for the internal carotid artery. The grooves for the middle meningeal vessels are sometimes converted into canals or tunnels for a short distance, especially in old skulls. The bones most deeply marked are the squamous portion of temporal, the great wing of the sphenoid, and the parietal.
The Posterior Cranial Fossa is the deepest and largest of the series. It is bounded in front by the dorsum sellse of the sphenoid and on each side by the superior border of the petrosal, and the mastoid portion of the temporal bone, the posterior inferior angle of the parietal, and the groove on the occipital bone for the transverse sinus; each of the bones mentioned takes part in the formation of its floor.
In the recent state the fossa lodges the cerebellum, pons, and medulla, and is roofed in by the tentorium cerebelli, a tent-like process of the dura mater attached to the ridges limiting the fossa above. It communicates with the general cranial cavity by means of the foramen ovale of Pacchionius, a large opening bounded in front by the clivus (basilar groove) and behind by the anterior free edge of the tentorium.
The foramen magnum, occupied in the recent state by the lower end of the medujla oblongata and its membranes, the vertebral, anterior spinal and posterior spinal arteries, the accessory (eleventh) cranial nerves, and the tectorial membrane.
media, and the internal auditory vessels.
The jugular foramen (foramen laoerum posterius), somewhat pyriform in shape, and divisible into three compartments. The anterior division, placed somewhat medially, transmits the inferior petrosal sinus and is sometimes completely separated by an iutra-jugular process of bone; the middle division transmits three cranial nerves, the ninth, tenth, and eleventh; and, in the posterior division, placed somewhat laterally, the transverse sinus becomes continuous with the internal jugular vein. A meningeal branch of the ascending pharyngeal or occipital artery enters the cranium through this division of the foramen.
The cranium of an average European has a capacity of 1450 c.c. The circumference, taken in a plane passing through the ophryon in front, the occipital point behind, and the pterion at the side, is 52 cm. The length from the ophryon to the occipital point is 17 cm., and the width between the parietals at the level of the zygomata is 12.5 cm. The proportion of the greatest width to the length is known as the cephalic index, i. e., index of breadth. A skull with an average cephalic index is mesaticephalic. When the index is above the average, it is brachycephalic (short and broad), and when below the average, dolichocephalic (long and narrow). The height from the basion to the bregma is nearly the same as the width at the level of the zygomata. The cranio-facial angle is about 96°.
In man the skull during development passes thi-ough three stages. At first the brain vesicles are enclosed in a sac of indifferent tissue which ultimately becomes tough and fibrous to form the membranous cranium. This, in turn, is partly converted into the membrane or roof bones of the cranium, whilst the remainder is represented in the adult by the dura mater. At the sides and base of the membranous cranium, however, cartilage is deposited, chondro -cranium, in which, as well as in the membranous tracts, osseous tissue appears in due course. Eventually, as osseous box is formed, consisting of membrane bones and cartilage bones intricately interwoven.
Further details are given in fig. 141.
(2) The appendicular elements of the skull are a number of cartilaginous rods surrounding the visceral cavity — i. e., nose, mouth, and pharymx — which undergo a remarkable metamorphosis, and are represented in the adult by the ear bones, the styloid process, and the hyoid bone.
Metamorphosis of the Branchial or Visceral Bars
These rods of cartilage are named, f om before backward, the mandibular, hyoid, and thyreoid bars. They may with care be easily dissected in the foetus between the third and fourth months. Their metamorphosis is as follows: — •
The two extremities of the mandibular bar (cartilago Meckehi) ossify; the distal end ultimately forms a portion of the mandible near to the symphysis (see p. 98); the pro.ximal end ossffies as the malleus and incus. The intermediate portion disappears; the only vestige is a band of fibrous tissue, the spheno-mandibular ligament, extending from the spine of the sphenoid to the spine of the mandible.
The hyoid bar fuses distaUy with the thyreoid bar, and forms part of the hyoid bone. Its proximal end becomes the stapes, the tympano-hyal portion of the styloid process (fused with the petro-mastoid), and the stylo-hyal or free portion of the process. The succeeding portion (epl-hyal segment) is represented in the adult by the stylo-hyoid ligament, and the lowest segment, or cerato-hyal, by the small cornu of the hyoid.
reoidean arches.
In addition to these structures ossifications occur in the connective tissue of the maxillary process, a structure which may be regarded as forming the anterior part of the first branchial arch, and in the fronto-nasal process. The ossifications in the maxillary process give rise to the pterygoid (medial pterygoid process of the sphenoid), the palate, the maxiUa, and the zygomatic, while that in the fronto-nasal process forms the premaxilla.
The Skull at Birth
The skull at birth presents, when compared with the adult skull, several important and interesting features. Its peculiarities may be considered under three headings: — The pecuharities of the fcetal skuU as a whole; the construction of the individual bones; the remnants of the chondral skull.
l-The most striking featm'es of the skull at birth are, its relatively large size in comparison with the body, and the predominance of the cranial over the facial portion of the skull (8_to 1) ; the latter is, in fact, very smaU.
The frontal and parietal eminences are large and conspicuous; the sutures are absent; the adjacent margins of the bones of the vault are separated by septa of fibrous tissue continuous with the dura mater internally and the pericranium externally; hence it is difficult to separate the roof bones from the underlying dura mater, each being lodged, as it were, in a dense membranous sac. The bones of the vault consist of a single layer without any diploe, and their cranial surfaces present no digital impressions. Six membranous spaces e.xist, named fontaneUes: two are median, the frontal [fonticulus frontalis; major] being anterior and the occipital [fonticulus occipitahs; minor] posterior. Two exist on each side, termed anterior [fonticulus sphenoidalis] and posterior [fonticulus mastoideiis] lateral fontanelles. Each angle of the parietal bones is in relation with a fontanelle. The anterior fontanelle is lozenge-shaped, the posterior triangular. The lateral fontanelles are nregular in outUne. The lateral fontanelles close soon after birth; the occipital fontanelle closes in the first year, and the frontal during the second year.
Turning to the base of the skull, the most striking points are the absence of the mastoid processes, and the large angle which the pterygoid plates form with the skull-base, whereas in the adult it is almost a right angle. The base of the skull is relatively short, and the lower border of the mental symphysis is on a level with the occipital condyles.
with the conchje.
Growth takes place rapidly in the first seven years after birth. There is a second period of rapid growth at puberty, when the air sinuses develop, and this affects especially the face and frontal portion of the cranium.
The occipital bone consists of four distinct parts, which have already been described. Compared with the adult bone, the following are the most important points of distinction: — ■ There is no pharyngeal tubercle or jugular process ; the squamous portion presents two deep fissures separating the interparietal from the supra-occipital portion and extending medially
absent.
The sphenoid in a macerated foetal skuU falls into three pieces: (1) united pre- and postsphenoids, orbito-sphenoids, and lingulse, and (2 and 3) the ali-sphenoids. The pre-sphenoid is quite solid and connected with the ethmo-vomerine cartilage, and presents no traces of the air sinuses which occupy this part in the adult skull. The pre-sphenoid by its upper surface forms part of the anterior cranial fossa, from which it is subsequently excluded by the growth of the orbito-sphenoids. The optic foramina are large and triangular in shape. The lingulae
stand out from the basi-sphenoid as two lateral buttresses, and at the tuberculum sellse is the basi-pharyngeal canal, which in the recent bone is occupied by fibrous tissue. The dorsum sellae is still cartilaginous. The ali-sphenoids with the pterygoid processes are separated^from the rest of the bone by cartilage. The foramen rotundum is complete, but the future foramen ovale is merely a deep notch in the posterior border of the great wing, and there is no foramen spinosum. The pterygoid processes are short, and each medial pterygoid plate presents a broad surface for articulation with the lingula. The pterygoid canal is a groove between the medial pterygoid plate, the lingula, and great wing.
The temporal bone at birth consists of three elements, the petrosal, squamosal, and tympanic. The petrosal presents a large and conspicuous floccular fossa; the hiatus Fallopii is a shallow bay lodging the geniculate gangUon of the facial nerve. There is a relatively large mastoid antrum, but no mastoid process. The styloid process is unossified, but the tympanohyal may be detected as a minute rounded nodule of bone near the stylo-mastoid foramen.
The squamosal has a very shallow mandibular fossa and a relatively large post-glenoid tubercle. The posterior part of the inferior border is prolonged downward into an uncinate process {post-auditory process) which closes the mastoid antrum laterally.
The frontal 'consists of two bones separated by a median vertical (metopic) suture. The frontal eminence is very pronounced, but the superciliary arche=i and frontal sinuses are wanting. The frontal spine, which later becomes one of the most conspicuous features of this bone, is absent. There is no temporal line. gil
The parietal is simply a quadrilateral lamina of bone, concave on its inner and convex on the outer surface. The parietal eminence, which indicates the spot in which the ossification of the bone commenced, is large and prominent. The grooves for blood-sinuses, as in other cranial
sists in the adult. The sinus is a shallow depression.
The mandible at birth consists of two halves united by fibrous tissue in the fine of the future symphysis. Each half is a bony trough lodging teeth. The trough is divided by thin osseous partitions into five compartments: of these, the fifth is the largest, and is often subdivided by a ridge of bone. The floor is traversed by a furrow as far forward as the fourth socket (that for the first milk molar), where it turns outward at the mental foramen. This furrow lodges the inferior alveolar nerve and artery, which enter by the large mandibular foramen. The condyle is on a level with the upper border of the anterior extremity of the bone.
The palate bones differ mainly from those in the adult in that the vertical and horizontal plates are of the same length; thus the nasal fossae in the foetus are as wide as they are high, whereas in the adult the height of each nasal fossa greatly exceeds the width.
which rests upon the hard palate, is broad, and the bone presents quite a different appearance from that in the adult. The nasal bones are short and broad; the zygomatics and inferior conchae are relatively very large; and the lacrimals are thin, frail, and dehoate lamellae.
It has aheady been pointed out that at an early date the base of the skull and the face are represented by hyahne cartilage, which for the most part is replaced by bone before birth. Even at birth remnants of this primitive chondral skull are abundant. In the cranium, cartilaginous tracts exist between the various portions of the occipital bone, as well as at the line of
THE MORPHOLOGY OF THE SKULL 125
junction of the occipital with the petrosal and sphenoid. The dorsum sellae is entirely cartilaginous at birth, and the last portion of this cartilage disappears with the ankylosis of the basi-occipital and basi-sphenoid about the twentieth year. A strip of cartilage unites the alisphenoids with the hngulae, and for at least a year after bu-th this cartilage is continuous with that which throughout life occupies the foramen lacerum. A strip of cartilage exists along the posterior border of the orbito-sphenoid, and not unfrequently extends lateralward to the pterion. In the adult skull it is replaced by ligamentous tissue.
The ethmo-vomerine plate is entkely cartilaginous, and near the end of the nose supports the lateral nasal cartilages, remnants of the fronto-nasal plate. The fate of the ethmo-vomerine plate is instructive. The upper part is ossified to form the mesethmoid; the lower part atrophies from the pressure exerted by the vomer; the anterior end remains as the septal cartilage. The lateral snout-like extremities of the fronto-nasal plate persist as the lateral cartilages of the
The various foramina and canals in the skull which give passage to nerves may be arranged in two groups, primary and secondary. Primary foramina indicate the spots where the nerves leave the general cavity of the dura mater, and as this membrane indicates the limit of the primitive cranium, a cranial nerve, in a morphological sense, becomes extra-cranial at the point where it pierces this membrane. In consequence of the complicated and extraordinary modifications the vertebrate skull has undergone, many nerves traverse, in the adult skull, bony tunnels and canals which are not represented in the less complex skulls of low vertebrates, such as sharks and rays. To such foramina and canals the terms secondary or adventitious may be
The Primary Foramina
1. Foramen magnum. — This is bounded by four distinct centres, the supra-, basi-, and two ex-ocoipitals. It transmits the accessory (eleventh) pair of cranial nerves, the vertebral arteries and their anterior and posterior spinal branches, the medulla oblongata and its membranes, and the membrana tectoria.
2. The hypoglossal. — At birth this is a deep notch in the anterior extremity of the exocoipital, and becomes a complete foramen when the basi- and ex-occipitals fuse. Occasionally it may be complete in the ex-occipital, but it indicates accurately the line of union of these two elements of the occipital bone. It transmits the hypoglossal nerve, the meningeal branch of the ascending pharyngeal artery, and its venae comitantes.
3. Jugular foramen. — This occupies the petro-occipital suture, and is formed by the basiand ex-occipital in conjunction with the petrosal. It transmits the glosso-pharyngeal, vagus, and accessory nerves, a meningeal branch of the ascending pharyngeal artery, and receives the transverse and inferior petrosal sinuses.
4. Auditory. — This marks the point of confluence of the groups of centres termed pro-otic and opisthotic. It transmits the facial and auditory nerves, the pars intermedia, and the auditory twig of the basilar artery.
5. Trigeminal. — This is only a foramen when the dura mater is present in the skull. It is a notch at the apex of the petrosal converted into a foramenby the tentorium. The main trunk of the trigeminal nerve, with the small motor root (masticator nerve), traverses it.
Foramina transmitting the various subdivisions of the trigeminal nerve. — The primary foramen of exit for the trigeminal nerve is formed partly of bone and partly of membrane at the apex of the petrosal. The three divisions of the nerve issue through secondary foramina.
(a) The superior orbital (sphenoidal) fissure is an elongated chink, bounded above by the orbital wing and below by the great wing of the sphenoid, medially by the body of the sphenoid, and laterally by the frontal. It opens into the orbit, and transmits the third, fourth, first (ophthalmic) division of the trigeminal and abducens nerves, also the ophthalmic vein or veins.
(6) The foramen rotundum is the only exception to the ru,le relating to the formation of nerve-foramina; it is probably a segment of the superior orbital fissure. The foramen is really a canal running from the middle cranial fossa to the pterygo-palatine fossa, and transmits the second or maxillary division of the trigeminal.
(c) The foramen ovale at birth is a gap in the hinder border of the great wing (ali-sphenoid) of the sphenoid, and is converted into a foramen by the petrosal; subsequently it becomes complete in the sphenoid. It transmits the thii'd or mandibular division of the trigeminal and the small or motor root, the small superficial petrosal nerve (which occasionally passes thi-ough a separate foramen), and the small meningeal artery with its venae comitantes.
The ethmoidal canals. — These commence in the suture between the lamina papyracea and the frontal bone, and traverse the space between the upper surface of the lateral mass of the ethmoid and the horizontal plate of the frontal, to emerge on the cribriform plate; they are situated outside the dura mater. The anterior foramen transmits the anterior ethmoidal branch of the ophthalmic, which subsequently gains the nasal cavity by passing through the ethmoidal fissure by the side of the crista galli.
The infra-orbital canal indicates the line of confluence of the maxillary and malar centres of the maxilla; occasionaOy it is completed by the zygomatic; rarely it is incomplete above, and communicates by a narrow fissure with the orbit. It lodges the infra-orbital nerve and artery.
The zygomatico-temporal foramen is situated in the suture between the zygomatic and the greater wing of the sphenoid (ali-sphenoid) ; it transmits the temporal branch of the zygomatic nerve and a branch of the lacrimal artery. In the adult this foramen may be wholly confined to the zygomatic bone.
The zygomatico -facial canals traverse the zygomatic bone, and indicate the line of confluence of the two chief centres for this bone. The facial twigs of the zygomatic nerve issue from them accompanied by arterial twigs.
The spheno-palatine foramen is a deep groove between the orbital and sphenoidal processes of the palate bone, converted into a foramen by the sphenoidal concha. It is traversed by the naso-palatine nerve and artery as they enter the nasal from the pterygo-palatine fossa.
The pharyngeal foramen is situated between the sphenoidal process of the palate bone, the medial pterygoid plate of the sphenoid, and the sphenoidal concha. The pharyngeal branch of the spheno-palatine ganghon and a branch of the spheno-palatine artery pass through it.
The pterygoid (Vidian) canal is trumpet-shaped: the narrower end is situated in the foramen lacerum; the broader orifice opens on the posterior wall of the pteryo-palatine fossa. The canal is 10 mm. long; in the fcetal skull it is a chink between the base of the medial pterygoid plate, the ah-sphenoid, and the lingula of the sphenoid. The canal is traversed by the Vidian branch of the spheno-palatine ganglion and the Vidian artery.
The posterior (greater) palatine canal is a passage left between the maxilla, the vertical plate and tuberosity of the palate bone and the medial pterygoid plate; it commences on the hard palate by the greater palatine foramen. The descending palatine nerve and artery traverse this canal. Several foramina open from it. In the suture between the vertical plate of the palate bone and the maxilla, two small openings allow minute nerves to issue for the middle and inferior nasal conchae. In the fissures between the tuberosities of the palate and maxillee, and the pterygoid plates, the posterior and middle palatine nerves issue. These are sometimes called the posterior and middle (smaller) palatine canals.
The mandibular or inferior dental canal runs in the mandible between the dentary and Meckel's cartilage of the mandible. The posterior orifice of the canal is the mandibular (inferior dental) foramen; the anterior orifice is the mental foramen. The inferior alveolar nerve and artery enter the canal at its posterior orifice; the mental foramen allows the mental nerve to escape from the canal accompanied by the mental artery.
Foramina transmitting the facial nerve and its branches. — The main trunk of the facial enters the internal auditory meatus and traverses the facial canal. In the early embryo the nerve lies on the petrosal, and is not covered in with bone until the fifth month of foetal life. The terminal orifice, the stylo-mastoid foramen, is situated between the tympanic, tympanohyal, and epiotic elements of the complex temporal bone.
The 'iter chorda posterius' is a chink between the squamosal and the tympanic elements, and allows the chorda tympani nerve to enter the tympanum. The fissure of exit for this nerve is the subdivision of the petro-tympanic fissure termed the canal of Huguier, or 'iter chordae anterius.' The petro-tympanic fissure lies between the tympanic plate and the squamosal. It transmits the tympanic branch of the internal maxillary artery, and lodges the anterior process of the malleus.
The inferior orbital (spheno-maxillary) fissure is situated between the posterior border of the orbital plate of the maxilla and a smooth ridge on the orbital surface of the great wing of the sphenoid. It transmits the superior maxillary division (second) of the fifth nerve, the zygomatic nerve, branches of the spheno-palatine ganglion to the orbit, and a communicating vein from the ophthalmic to the pterygoid plexus.
The ribs [costse] (figs. 154, 155) twelve in number on each side, constitute a series of narrow, flattened bones, extending from the sides of the thoracic vertebrae toward the median line on the anterior aspect of the trunk. The anterior ends of the first seven pairs are connected, by means of their costal cartilages, with the sides of the sternum, and on this account the first seven ribs on each side are
THE RIBS 127
termed true or sternal ribs. The remaining five pairs, known as false or asternal ribs, may be arranged in two sets: — one, including the eighth, ninth, and tenth ribs, in which the cartilages of the anterior extremities are connected together, and the other, including the eleventh and twelfth, in which the anterior extremities, tipped with cartilage, are free. The eleventh and twelfth are known, in consequence, as the floating ribs. Thus, the first seven are vertebro -sternal; the eighth, ninth, and tenth, vertebro -chondral; the eleventh and twelfth, vertebral ribs.
The ribs increase in length from the first to the seventh, and decrease from the seventh to the twelfth. They also vary in their direction, the upper ones being less oblique than the lower. The obliquity is greatest at the ninth rib and gradually decreases from the ninth to the twelfth.
Typical characters of a rib (fig. 154). — The seventh is regarded as the most typical rib. It presents for examination a vertebral extremity or head; a narrow portion or neck; a sternal extremity; and an intermediate portion, the body or shaft.
The crest is
connected by an interarticular ligament with an intervertebral disc, and the facets articulate with the costal pits on the sides of the bodies of two vertebrae (sixth and seventh) . As a rule, the lower facet is the larger, and articulates with the thoracic vertebra, to which the rib corresponds in number. This is the primary facet, and is the one represented in those ribs which possess only a single facet on the rib-head. The anterior margin is lipped for the attachment of the radiate ligament.
The neck [coUum costae] is that portion of the rib extending from the head to the tubercle. It is flattened from before backward and the posterior surface is in relation with the transverse process of the lower of the two vertebrae with which the head articulates; it forms the anterior boundary of the costo-transverse foramen, and is rough where it is attached to the neck (middle costo-transverse) ligament. The anterior surface is flat and smooth. The superior border of the neck, continuous with the corresponding border of the shaft, presents a rough crest [crista colli] for the anterior costo-transverse ligament. The inferior border of the neck is rounded and continuous with the ridge of the costal groove. This difference in the relation of the neck, to the upper and lower borders of the rib-shaft, is useful in determining to which side a rib belongs.
The tubercle, situated behind at the junction of the neck with the shaft, consists of an upper and lateral part, rough for the attachment of the posterior costotransverse ligament, and a lower and medial part, bearing a facet for articulation with a pit near the tip of the transverse process. The tubercle projects below the lower edge of the rib to form a crest, marking the beginning of the costal groove.
The body is strongly curved and presents for examination two surfaces and two borders. At first the curve is in the same plane as the neck, but it quickly turns forward at a spot on the posterior surface of the shaft known as the angle, where it gives attachment to the ilio-costalis muscle and some of its subdivisions. The rib has also a second or upward curve, beginning at the angle. These curves are expressed by describing the main curve as disposed around a vertical, and the second or upward curve around a second transverse axis.
neighbourhood of the angle.
Besides the two curves now described, the rib is slightly twisted on itself, so that the surfaces which look medially and laterally behind are placed obhquely in front and look downward as well as medially, and upward as well as laterally.
The external sui-face of the rib is convex, and gives attachment to muscles. Near its anterior extremity it forms a somewhat abrupt curve, indicated by a ridge on the bone, which gives attachment to the serratus anterior (niagnus) muscle, and is sometimes called the anterior angle.
The internal surface is concave and presents near its inferior border the costal groove [sulcus costae]. The groove is best marked near the angle, and gradually becomes shallower toward the anterior extremity of the rib, where it is finally lost; it lodges the intercostal vessels and nerve. The ridge limiting the
gives attachment to the internal intercostal muscle.
The superior border is rounded, and affords attachment to the internal and external intercostal muscles. The inferior border commences abruptly near the angle, and gives attachment to the external intercostal muscle.
cartilage
Blood-supply. — -The ribs are very vascular and derive numerous branches from the intercostal arteries. The branches in the shaft run toward the vertebral end, whilst those in the head and neck run, as a rule, toward the shaft. In the neighbourhood of the tuberosity the vessels do not seem to have any constant arrangement.
eleventh, and twelfth.
The first rib is the broadest, flattest, strongest, shortest, and most curved of all the series. It is not twisted, and is so placed that its superior sm-face looks forward as well as upward, and its inferior surface backward as well as downward. The head is small, and as a rule is furnished
with only one articular facet. The neck, longer than that of most of the ribs, is slender and rounded. The tubercle is large and prominent. The shaft lies for its whole extent nearly in one plane, has no angle, and is curved in one du'eotion only, i. e., around a vertical axis. The superior surface presents two shallow grooves, separated near the inner border by a rough surface (scalene tubercle or tubercle of Lisfranc) for the scalenus anterior muscle. Between the groove for the artery and the tubercle is a rough surface for the insertion of the scalenus medius, and between the groove and the outer margin is an area for the origin of the serratus anterior {magnus). The inferior surface is uniformly flat and lacks a subcostal groove. By the lateral portion, which is rough, it gives attachment to the internal intercostal muscle; the remainder of the inferior surface is in relation to pleura and lung. The lateral border is thick and rounded, and gives attachment to the external intercostal muscle, whilst the medial border, thin, sharp, and concave, receives the attachment of the fascia (Sibson's) covering the dome of the plem-a. The anterior extremity is thick and broad, and its upper margin, as well as the cartilage to which it is joined, afford attachment to the costo-olavicular ligament and the subclavius muscle. The costal cartilage of this rib is du-ectly united to the manubrium sterni, and occasionally the cartilage and the adjoining part of the anterior extremity of the rib are replaced by fibrous tissue.
artery.
The second rib'is much longer than the first, and although like it in being strongly curved round a vertical axis, in its form and general characters there is a closer resemblance to the ribs lower down in the series. The head is round and presents two facets, the costal groove is present, though faintly marked, and an angle is situated near the tubercle. The specially distinguishing featm-e of the rib, however, is a well-marked tuberosity on its outer surface somewhat near the middle, for the origin of a part of the first digitation, and the whole of the second digitation of the serratus anterior {magnus). Between the tuberosity and the tubercle the outer surface is smooth and rounded and gives attachment to the scaletius posterior, the serratus posterior superior, the ilio-costalis cervicis {cervicalis ascendens), and the ilio-costalis dorsi (accessorius) . The internal sm-face is smooth and in relation to the pleura. The borders give attachment to the intercostal muscles, the upper, to those of the first space, the lower, to those of the second. The shaft of the second rib is not twisted on its own axis, so that both ends can he fiat on the table. The second rib receives vessels from the superior intercostal branch of the subclavian artery and the first aortic intercostal.
The tenth rib is distinguished by a single facet on the head for articulation with the body of the tenth thoracic vertebra. Occasionally there are two facets, in which case the rib articulates also with the ninth thoracic vertebra. The tenth rib, like the ribs immediately above, is long, curved, presents a deep costal groove, a well-marked tuberosity and an angle. It may
be noted, however, that the distance between the tubercle and the angle in this rib is greater than in the ribs above. Speaking generally, the distance between these points increases from above downward — a disposition which is useful in at once determining if any given rib belongs to the upper or lower end of the series.
The eleventh rib is peculiar in that it has a single facet on the head, a feebly marked angle some distance from the head, a shallow costal groove, no tubercle, and no neck. The tubercle is sometimes represented by a slight elevation or roughness without any articular facet. The anterior extremity is pointed.
The twelfth rib has a large head furnished with one facet for articulation with the root (pedicle) of the tweUth thoracic vertebra. The shaft is narrow and extremely variable in length (3 to 20 cm.). It is usually somewhat longer than the first rib, but it may be shorter. There is no tubercle, no angle, no neck, no costal groove. The anterior extremity is pointed. Posteriorly, the upper border is smooth and somewhat rounded; the lower border is sharp and rough.
The costal cartilages are bars of hyaline cartilage attached to the anterior extremities of the ribs, and may be regarded as representing unossified epiphyses. Like the shaft of a rib, each cartilage has an outer and inner surface. The outer surfaces give origin and insertion to large muscles, and the inner surfaces, from the second to the sixth inclusive, are in relation with the transversus thoracis {triangularis sterni) . The upper and lower borders serve for the attachment of the internal intercostal muscles. The upper seven cartilages, and occasionally the eighth, are connected with the sternum. Of these, the first fuses with the manubrium sterni and the remaining six are received into small articular concavities, and retained by means of ligaments.
The cartilages of the vertebro-ohondral ribs are united to one another and to the seventh costal cartilage by ligaments (sometimes by short vertical bars of cartilage), while those of the vertebral ribs form no such attachment, but lie between the abdominal muscles. The inner surfaces of the lower six costal cartilages afford attachment to the diaphragrn and the transversalis muscle.
Each of the second, third, fourth, and fifth costal cartilages articulates with the side of the sternum, at a point corresponding to the junction of two sternebrse. The sixth and seventh (and eighth when this reaches the sternum) are arranged irregularly. As a rule, the sixth lies in a recess at the side of the fifth sternebra; the seventh corresponds to the line of junction of the meso- and metasternum; and the eighth articulates with the metasternum (see figs. 158, 161).
the aortic intercostals and from the internal mammary arteries.
Ossification. — At the eighth week of intra-uterine life the ribs are cartilaginous. About this date a nucleus appears near the angle of each rib, and spreads with great rapidity along'the shaft, and by the fourth month reaches as far as the costal cartilage. At this date the length of rib-shaft bears the same proportion to that of the costal cartilage as in adult life. Whilst the ribs are in a cartilaginous condition, the first eight reach to the side of the sternum, and even after ossification has taken place, the costal cartilage of the eighth rib, in many instances, retains its articulation with the sternum up to as late as the eighth month (fig. 158). This relationship may persist through life, but usually the cartilage retrogresses, and is replaced by ligamentous tissue. About the fifteenth year a secondary centre appears for the head of each rib, and a little later one makes its appearance for the tubercle, except in the eleventh and tweKth ribs. Frequently epiphyses are developed on both parts of the tubercle (see figs. 159 and 160). The
Variations in the Number and Shape of the Ribs
The ribs may be increased in number by addition either at the cervical or lumbar end of the series, but it is extremely rare to find an additional rib or pair of ribs in both the cervical and lumbar regions in the same subject.
Cervical ribs are fairly common; as a rule, they are of small size and rarely extend more than a few millimeters beyond the extremity of the transverse process (see p. 35). Rarely they exceed such insignificant proportions and reach as far as the sternum; between these two extremes many varieties occur. In one case Tui'ner was able to make a thorough dissection of a specimen in which a complete cervical rib existed. Its head articulated with the body of the
seventh cervical vertebra and had a radiate ligament. The tubercle was well developed, and articulated with the transverse process. The costal cartilage blended with that of the first thoracic rib, and gave attachment to the costo-clavicular ligament. Between it and the first thoracic rib there was a well-marked intercostal space occupied by intercostal muscles. It received the attachment of the scalenus anterior and meditis muscles, and it was crossed by the subclavian artery and vein. The nerves of the intercostal space were supplied by the eighth cervical and first thoracic. The artery of the space was derived from the dee)] cervical, which, with the superioi intercostal, arose from the root of the vertebral. The head of the first thoracic rib in this specimen articulated with the seventh cervical, as well as with the first thoracic vertebra. An interesting; fact is also recorded in the careful account of this specimen. There was no movable twelfth thoracic rib on the same side as this well-developed cervical rib, and the twelfth thoracic vertebra had mammillary and accessory processes, and a strong elongated costal process, and was in linear series with the lumbar transverse processes.
Articular facet
Gruber and Turner, from a careful and elaborpte study of this question, summarise the variations in the cervical rib thus: — It may be very short and possess only a bead, neck, and tubercle. When it extends beyond the transverse process, its shaft may end freely or join the first thoracic rib: this union may be effected by bone, cartilage, or ligament. In very rare instances it may have a costal cartilage and join the manubrium of the sternum. Net unfrequently a process, or eminence, exists on the first thoracic rib at the spot where it articulates with a cervical rib.
Lumbar ribs are of less significance than cervical ribs and rarely attain a great length. Their presence is easily accounted for, as they are the differentiated costal elements of the transverse processes. They are never so complete as the cervical ribs, and articulate only with the transverse processes; the head never reaches as far as the body of the vertebra, and there is no neck or tubercle. An extra levator costce muscle is associated with a lumbar rib.
Epiphysis of the articular facet of the tubercle
Not the least interesting variation of a rib is that known as the bicipital rib. This condition is seen exclusively in connection with the first thoracic rib. The vertebral end consists of two Hmbs which lie in different transverse planes. These bicipital ribs have been especially studied in whales and man. This abnormality is due to the fusion of two ribs, either of a cervical rib with the shaft of the first thoracic; or the more common form, the fusion of the first and second true ribs.
Among unusual variations of ribs should be mentioned the replacement of the costal cartilage and a portion of the rib-shaft by fibrous tissue, a process which occurs normally in the case of the eighth rib during its development.
The sternum (figs. 161, 162) is a flat, oblong plate of bone, situated in the anterior wall of the thorax, and divisible into three parts, called respectively — (1)' the manubrium sterni (presternum), (2) the gladiolus (mesosternum), constitutfng the body of the bone, and (3) the xiphoid (or ensiform) process (metasternura). In the young subject it consists of six pieces or segment (sternebrae) . Of these, the first remains separate throughout life and forms the manubrium; the sue-
also distinct until middle life, is represented by the xiphoid process.
In its natural position the sternum is inclined obliquely from above downward and forward, and corresponds in length to the spine from the third to the ninth thoracic vertebra. It is not of equal width throughout, being broader above at the manubrium and narrow at the junction of this piece with the body. Toward the lower part of the body the sternum again widens, and then suddenly contracts at its junction with the xiphoid process which constitutes the narrowest part.
The manubrium or first piece of the sternum forms the broadest and thickest part of the bone, and is of a somewhat triangular form with the base directed upward and the apex downward. It presents for examination two surfaces and four borders. The anterior surface [planum sternale] is largely subcutaneous. It is slightly convex and directed obhquely upward and forward, is smooth and gives origin on each side to the sternal head of the sterno-mastoid and the pedoralis major. The posterior surface, almost flat, and directed downward and backward, affords origin near the lateral margins on each side; to the sterno-hyoid muscle above and the sterno-thyreoid muscle below. Of the four borders, the superior is the longest and much the thickest. In the middle is a curved, non-articular depression, called the jugular (interclavicular) notch, to which the fibres of the interclavicular ligament are attached, and at either end is an oval articular surface [incisura clavicularis], somewhat saddle-shaped and directed upward, backward, and lateral^ for the reception of the medial end of the clavicle. The circumference of the articular surface gives attachment to the sterno-clavicular ligaments. The lateral borders slope from above downward and medially and each presents an irregular surface above for the first costal cartilage and a small facet below, which, with an adjoining facet on the body, forms a notch for the second costal cartilage. The two articular surfaces are separated by a narrow curved edge in relation with the internal intercostal muscle of the first space. The lower border is thick and short and presents an oval rough surface which articulates with the upper border of the body, forming the sternal S3aichondrosis. The two opposed surfaces are separated by a fibro-cartilaginous disc, which may, however, become partially ossified in advanced age, and at the position of the joint there is usually an angle — the angle of the sternum — which can be felt as a transverse ridge beneath the skin. This is useful in locating the position of the second rib in the living subject.
The body (gladiolus) or second piece of the sternum is longer, narrower, and thinner than the manubrium. It is widest opposite the notches for the fifth costal cartilages and becomes narrower above and below. The anterior surface is flat, directed upward and forward, and marked by three transverse elevations which indicate the lines of junction of its four component parts. It gives attachment on each side to fibres of the pectoralis major, and occasionally presents a foramen — the sternal foramen — situated at the junction of the third and fourth pieces of the bone. The posterior surface is slightly concave, marked by lines corresponding to those on the anterior surface, and below gives attachment on each side to fibres of the transversus thoracis {triangularis sterni). The lateral borders present four whole notches [incisure costse] and two half-notches on each side, which articulate with the costal cartilages of the second to the seventh ribs inclusive; the two half-notches are completed by corresponding notches on the manubrium and the xiphoid process. Between the articular depressions the lateral border is curved and in relation to the internal intercostal muscles.
In order to appreciate the nature of these articular notches, it is advantageous to study the sternum in a young subject. Each typical sternebra presents four angles at each of which is a demi-notch. Between every two sternebrae there is an intersternebral disc so that when in position, each notch for a costal cartilage is formed by a sternebra above and below and an intersternebral disc in the middle, thus repeating the relation of the rib-head to the vertebral centre. Later in life these fuse more or less together, except in the case of the first and second sternebrae, which usually remain separate to the end of life. The first (pre-sternum) is the most modified of all the sternebrae, and differs from them in the fact that the costal cartilage of the first rib is continuous with it, and in fact that it supports the clavicles. Occasionally a rounded pisiform bone is seen on each side, medial to the articular notch for the clavicle; these are the supra-sternal bones.
metasternum
part of the sternum and is subject to many variations in form, being sometimes pointed, broad and thin, occasionally bifid or perforated by a foramen, and sometimes bent forward, backward, or deflected to one side. In structure it is cartilaginous in early life, partially ossified in the adult, but in old age it tends to become ossified throughout and to fuse with the body.
The anterior surface of the xiphoid process gives attachment to a few fibres of the rectus ahdominis muscle and the chondro-xiphoid ligament, the posterior surface to the sternal fibres of the diaphragm, and the lowest fibres of the transversus thoracis {triangularis sterni), whilst
tinuous with the linea alba.
Differences according to sex. — The sternum differs somewhat in the two sexes. The female sternum is relatively shorter, the diminution being almost confined to the body. In the male the body is more than twice as long as the manubrium, whereas in the female it is usually less than twice the length of the first piece.
of the internal mammary.
Development of the sternum. — -The osseous sternum is preceded by a continuous or nonsegmented central sternal cartilage formed in the following way When the cartilaginous ribs first appear in the embryo, their anterior or ventral ends fuse together on either side of the middle fine. For some time a median fissure is present, bordered by two sagittaUy directed strips of cartilage with each of which at first nine ribs are joined. As development proceeds the two strips come into contact in the middle line and fuse from before backward to form a median sternal cartilage. The eighth cartilage generally loses its sternal attachment, although in some cases it remains permanently articulated with the side of the ensiform process. The ninth
costal cartilage becomes subdivided, one part remaining attached to the sternum and forming the xiphoid process, whilst the end still continuous with the rib acquires a new attachment to the eighth cartilage. The ends adherent to the sternum may remain separate and give rise to a bifid xiphoid process, though much more frequently they unite, leaving a small foramen.
At first, therefore, the sternum and costal cartilages are continuous. A joint soon forms between the presternum and mesosternum, and others between the costal cartilages and the sternum (except in the case of the first) quickly follow. The division of the mesosternum into segments is a still later formation and arises during the process of ossification.
On the other hand, a view has been advanced by Professor A. M. Paterson that the sternum is not a bilateral structure, but is laid down, as shown in human sterna of the third month, as a simple median band of hyahne cartilage, in complete fusion with the costal cartilages on each side and presenting no differentiation of its component parts. From a study of the earliest stages of the development of the sternum, its comparative anatomy and structure, Professor Paterson has, moreover, brought forward evidence which indicates its independence in the first instance of costal elements and its genetic association with the shoulder girdle.
Ossification. — The ossification of the sternutn is slow and irregular. The process begins in the presternum (manubrium) by a single centre about the sixth month of intra-uterine life, though occasionally other accessory centres are superadded.
The mesosternum (body) usually ossifies from seven centres. The upper segment ossifies from a single median nucleus about the eighth month, and below this, three pairs of ossific nuclei appear, which may remain for a long time separate. Of these, two parrs for the second and third segments are visible at birth, and those for the lower segment make their appearance toward the end of the first year. The various lateral centres unite in pairs, so that at the sixth year the sternum consists of six sternebra3, the lowest (metasternum) being cartilaginous. Very often, however, there are only four centres of ossification in the gladiolus, as shown in fig. 165. Gradually the four pieces representing the mesosternum fuse with one another, and
defect of ossification.
The metasternum is always imperfectly ossified, and does not join with the mesosternum till after middle life. The presternum and mesosternum rarely fuse. The dates given above for the various nuclei, and for the union of the various segments, are merely approximate, hence the sternum affords very uncertain data as to age.
Abnormalities of the Sternum. — The mode of development of the sternum as described above is of importance in connection with some deviations to which it is occasionally subject. In rare instances the two lateral halves fail to unite, giving rise to the anomaly of a completely cleft sternum. The union of the two halves may occur in the region of the manubrium and fail below, whilst in other cases the upper and lower parts have fused but remain separate in the middle. The clefts are in many instances so small as not to be of any moment, and are not even recognised until the skeleton is prepared. In a few individuals, however, they have been so extensive as to allow the pulsation of the heart to be perceptible to the hand, and even to the eye, through the skin covering the defect in the bone.
A common variation in the sternum is asymmetry of the costal cartilages. Instead of corresponding, the cartilages may articulate with the sternum in an alternating manner. The cause of this asymmetry is not known.
The bony thorax (fig. 166) is somewhat conical in shape, deeper behind than in front and compressed antero-posteriorly, so that in the adult it measures less in the sagittal than in the transverse axis. The posterior wall, formed by the thoracic vertebrae and the ribs as far
photograph of a man 33 years old.
outward as their angles, is convex from above downward, and the backward curve of the ribs produces on each side of the vertebrae a deep furrow, the costo-vertebral groove, in which the sacro-spinalis (erector spinoe) muscle and its subdivisions are lodged. The anterior wall is formed by the sternum and costal cartilages. It is slightly convex and inchned forward in its lower part, forming an angle of about 20° with the vertical plane. The lateral walls are formed by the ribs from the angles to the costal cartilages. The top of the thorax presents an elUptical aperture, the superior thoracic aperture, which measures on an average 12.5 centimetres (5
THE CLAVICLE 139
inches) transversely and 6.2 centimetres (2J inches) in its sagittal axis. It is bounded by the first thoracic vertebra behind, the upper margin of the manubrium sterni in front, and the first rib on each side. As the upper margin of the manubrium sterni is oftenest on a level with the disc between the second and third thoracic vertebrae, it follows that the plane of the opening is directed obliquely upward and forward. The angle of the sternum {angulus Ludovici) is usually opposite the body of the fifth thoracic vertebra and the xiphi-sternal junction corresponds to the disc between the ninth and tenth thoracic vertebrae. The lower aperture of the thorax is very irregular, and is formed by the twelfth thoracic vertebra behind, the twelfth ribs laterally, and in front by two curved lines, ascending one on either side from the last rib, along the costal margin to the lower border of the gladiolus. The two borders form the costal arch, which in the median line below the sternum forms the infrasternal angle. From this angle the xiphoid process projects downward. The intervals between the ribs are the intercostal spaces, and are eleven in number on each side.
The ratio of the sagittal and the transverse diameter of the thorax forms the thoracic index, which is higher in the female and in children, in whom the thorax is more rounded. In the embryo, the index is very much higher, the sagittal diameter being greater than the transverse. In the early embryo, the index is nearly 200; at birth it is about 90. In the adults it_ varies from 70 to 75, averaging 2 or 3 per cent, lower in the male than in the female. It is also lower in the negro than in the white race. (Rodes, Zeitschr. f. Morph. u. Anthrop., Bd. 9.)
A. BONES OF THE UPPER EXTREMITY
The bones of the upper extremity may be arranged in four groups corresponding to the division of the limb into four segments. In the shoulder are the clavicle and the scapula, which together constitute the pectoral or shoulder girdle; in the arm is the humerus; in the forearm are the radius and ulna; and in the hand the carpus, the metacarpus, and the phalanges.
The clavicle [clavicula] or collar bone (figs. 168, 169) is situated immediately above the first rib and extends from the upper border of the manubrium sterni, laterally and backward to the acromion process of the scapula. It connects the upper limb with the trunk, and is so arranged that whilst the medial end rests on the sterniun and first costal cartilage, the lateral end is associated with the scapula in all its movements, supporting it firmly in its various positions and preventing it from falling inward on the thorax.
The clavicle is a long bone, and when viewed from the front presents a double curvature, so that it somewhat resembles in shape the italic letter /. The medial curve, convex forward, extends over two-thirds of the length of the bone; the lateral, concave forward, is smaller and confined to the lateral part. For descriptive purposes the clavicle may be divided into a medial prismatic portion, a lateral flattened portion, and two extremities.
Prismatic portion. — The medial two-thirds of the bone, extending from the sternal extremity to a point opposite the coracoid process of the scapula, has the form of a triangular prism. This portion, however, is subject to considerable variations of form, being more cylindrical in ill-developed specimens and becoming almost quadrangular when associated with great muscular development. In a typical specimen it is marked by three borders separating three surfaces. Of these, the anterior surface is convex and divided near the sternal end by a prominent ridge into two parts, a lower, giving origin to the clavicular portion of the pectoralis major; an upper, for the clavicular portion of the sterno-cleidomastoid. Near the middle of the shaft the ridge disappears, the surface is smooth, and is covered by the platysma myoides. The posterior surface is concave, forming an arch over the brachial plexus and the subclavian artery, broadest medially and smooth in its whole extent. It gives origin near the sternal extremity to a part of the sterno-hyoid and occasionally to a few fibres of the sterno-thyreoid. Somewhere near the middle of this surface is a small foramen, directed laterally, for the chief nutrient artery of the bone, derived from the transverse scapular (suprascapular) artery. Sometimes the
foramen is situated on the inferior surface of the bone, in the subclavian groove. On the inferior surface near the sternal end is a rough area, the costal tuberosity, about three-quarters of an inch in length, for the attachment of the costoclavicular ligament, by which the clavicle is fixed to the first rib. More laterally is a longitudinal groove for the subclavius, bordered by two lips, to which the sheath of the muscle is attached. To the posterior of the two lips the layer of deep cervical fascia which binds down the posterior belly of the omo-hyoid to the clavicle is also attached.
Of the three borders, the superior separates the anterior and posterior surfaces. Beginning at the sternal end, it is well-marked, becomes rounded and indistinct in the middle, whilst laterally it is continuous with the posterior border of the outer third. The posterior border separates the inferior and posterior surfaces and forms the posterior lip of the subclavian
groove. It begins at the costal tuberosity and can be traced laterally as far as the coracoid tubercle, an eminence on the under aspect of the bone near the junction of prismatic and flattened portions. The anterior border is continuous with the anterior border of the flattened portion and separates the anterior and inferior surfaces. Medially, it forms the lower boundary of the elliptical area for the origin of the pecloralis major, and approaches the posterior border. Near the middle of the bone it coincides with the anterior lip of the subclavian groove.
Acromial facet
tened from above downward and presents two surfaces and two borders. The superior surface is rough and looks directly upward and gives attachment to the trapezius behind and the deltoid in front; between the two areas the surface is subcutaneous. On the inferior surface, near the posterior border, is a rough elevation, the coracoid (conoid) tubercle ; it overhangs the coracoid process and gives attachment to the conoid ligament. From the coracoid tubercle, a prominent ridge, the trapezoid or oblique line, runs laterally and forward to near the lateral end of the bone. To it the trapezoid ligament is attached. The conoid and trapezoid ligaments are the two parts of the coraco-clavicular ligament which binds the clavicle down to the coracoid process.
The anterior border is sharp, gives origin to the deltoid muscle, and frequently presents near the junction of the flattened and prismatic portions a projection known as the deltoid tubercle. The posterior border is thick and rounded, and receives the insertion of the upper fibres of the trapezius.
THE SCAPULA 141
Extremities. — The sternal extremity of the clavicle presents a triangular articular surface, directed medially, downward, and a little forward, slightly concave from before backward and convex from above downward, which articulates with a facet on the upper border of the manubrium sterni through an interposed interarticular fibro-cartilage.
Of the three angles, one is above and two below. The postero-inferior angle is prolonged backward, and so renders this surface considerably larger than that with which it articulates; the superior angle receives the attachment of the upper part of the fibro-cartilage. The lower part of the surface is continuous with a facet on the under aspect of the bone, medial to the costal tuberosity, for the first costal cartilage. The circumference of the extremity is rough, and gives attachment to the interclavicular ligament above and the anterior and posterior sterno-clavicular ligaments in front and behind.
The acromial extremity presents a smooth, oval, articular facet, flattened or convex, directed shghtly downward for the acromion; its border is rough, for the attachment of the capsule of the acromio-clavicular joint.
Sternal epiphyses
cavity, for the interior is occupied from end to end by cancellous tissue, the amount in the various parts of the bone being in inverse proportion to the thickness of the outer compact shell Ossification. — From observations made by F. P. Mall, D. C. L. Fitzwilliams, and E. Fawcett it seems almost certain that there are two centres of ossification of the shaft of the clavicle, at the juncture of the middle and lateral thirds. They appear very early, about the fifth week of embryonic life, and rapidly fuse. The ossific process extends medially and laterally along the shaft toward the medial and lateral extremities, respectively. About the eighteenth year a secondary centre appears at the sternal end and forms a small epiphysis which joins the shaft about the twenty-fifth year.
The scapula (figs. 171, 172) is a large flat bone, triangular in shape, situated on the dorsal aspect of the thorax, between the levels of the second and seventh ribs. Attached to the trunk by means of the clavicle and various muscles it articulates with the lateral end of the clavicle at the acromio-clavicular joint, and with the humerus at the shoulder-joint. The greater part of the bone consists of a triangular plate known as the body, from which two processes are prolonged: one anterior in position, is the coracoid; the other, posterior in position, is the spine, which is continued laterally into the acromion.
The body presents for examination two surfaces, three borders, and three angles. The costal (anterior) surface, or venter, looks considerably medialward, is deeply concave, forming the subscapular fossa, and marked by several oblique lines which commence at the posterior border and pass obliquely upward and laterally; these lines or ridges divide the surface into several shallow grooves, from which the suhscapularis takes origin, whilst the ridges give attachment to the tendinous intersections of that muscle. The lateral third of the surface is smooth and overlapped by the subscapularis, whilst medially are two small flat areas in front of the upper and lower angles respectively, but excluded from the subscapular fossa by. fairly definite lines and joined by a ridge which runs close to the vertebral border. The ridge and its terminal areas serve for the insertion of the serratus anterior {magnus).
The dorsal (posterior) surface is generally convex and divided by a prominent plate of bone — the spine — into two unequal parts. The hollow above the spine is the supraspinous fossa and lodges the supraspinatus muscle. The part below
the spine is the infraspinous fossa; it is three times as large as the supraspinous fossa, is alternately concave and convex, and gives origin to the infraspinatus. The muscle is attached to its medial three-fourths and covers the lateral fourth, without taking origin from it.
The infraspinous fossa does not extend as far as tlie axillary border, but is limited laterally by a ridge — the oblique hne— Which runs from the glenoid cavity — the large articular surface for the head of the humerus — downward and backward to join the posterior border a short distance above the inferior angle. Tliis line, which gives attachment to a stout aponeurosis, cuts ofi an elongated surface, narrow above for the origin of the teres minor, and crossed near its middle by a groove for the circumflex (dorsal) artery of the scapula; below, the surface is broader for the origin of the teres major and occasionally a few fibres of the latissimus dorsi. The two areas are separated by a line which gives attachment to an aponeurotic septum situated between the two teres muscles.
Teres ma jo
The supra- and infraspinous fossa communicate through the great scapular notch at the lateral border of the spine, and through the notch the suprascapular nerve and transverse scapular artery are transmitted from one fossa to the other.
Borders. — The three borders of the scapula are named superior, vertebral, and axillary. The superior is short and thin and extends from the upper angle to the coracoid process. Laterally it presents a deep depression, the scapular notch, to the extremities of which the superior transverse ligament is attached.
Not infrequently the notch is replaced by a scapular foramen, and it is interesting to note that a bony foramen occurs normally in some animals, notably the great ant-eater (Myrmecophaga jubata). The notch or foramen transmits the suprascapular nerve, whilst the transverse scapular artery usually passes over the ligament. From the adjacent margins of the notch and from the ligament the posterior belly of the omo-hyoid takes origin.
The vertebral border (sometimes called the base) is the longest, and extends from the upper or medial to the lower angle of the bone. It is divisible into three parts, to each of which a muscle is attached: an upper portion, extending from the medial (superior) angle to the spine, for the insertion of the levator scapulae; a middle portion, opposite the smooth triangular area at the commencement of the spine, for the rhomhoideus minor; and the lowest and longest portion, extending below this as far as the inferior angle, for the rhomhoideus major, the attachment of which takes place through the medium of a fibrous arch.
The axillary border is the thickest, and extends from the lower margin of the glenoid cavity to the inferior angle of the bone. Near its junction with the glenoid cavity there is a rough surface, about 2.5 cm. (1 in.) in length the infraglenoid tubercle, from which the long head of the triceps arises, and below
the tubercle is the groove for the circumflex (dorsal) artery of the scapula. The upper two-thirds of the border is deeply grooved on the ventral aspect and gives origin to a considerable part of the subscapidaris.
The medial (or superior) angle, forming the highest part of the body, is thin, smooth, and either rounded or approximating a right angle. It is formed by the junction of the superior and vertebral borders and gives insertion to a few fibres of the levator scapula. The inferior angle, constituting the lowest part of the body, is thick, rounded, and rough. It is formed by the junction of axillary and vertebral borders, gives origin to the teres major, and is crossed liorizontally by the upper part of the lalissimus dorsi, the latter occasionally receiving from it a small slip of fleshy fibres.
glenoid cavity is a wide, shallow, pyriform, articular surface for the head of the humerus, directed forward and laterally, with the apex above and the broad end below. Its margin is raised, and affords attachment to the glenoid ligament, which deepens its concavity. The margin is not, however, of equal prominence throughout, being somewhat defective where it is overarched by the acromion, notched anteriorly, and emphasised above to form a small eminence, the supraglenoid tubercle, for the attachment of the long head of the biceps.
The circumference and adjoining part of the neck give attachment to the articular capsule of the shoulder-joint, and the anterior border to the three accessory ligaments of the capsule, known as the superior, middle, and inferior gleno-humeral folds. The superior fold (Flood's ligament) is attached above the notch near the upper end; of the two remaining folds, which together constitute Schlemm's ligament, the middle is attached immediately above the notch and the inferior below the notch. In the recent state the glenoid fossa is covered with hyaline cartilage. The neck is more prominent behind than before and below than above, where it supports the coracoid process. It is not separated by any definite boundary from the body.
Processes. — The spine is a strong, triangular plate of bone attached obliquely to the dorsum of the scapula and directed backward and upward. Its apex is situated at the vertebral border; the base, corresponding to the middle of the neck, is free, concave, and gives attachment to the inferior transverse ligament, which arches over the transverse scapular (suprascapular) vessels and suprascapular nerve. Of the two borders, one is joined to the body, whilst the other is free, forming a prominent subcutaneous crest. The latter commences at the vertebral border, in a smooth triangular area, over which the tendon of the trapezius glides, usually without the intervention of a bursa, as it passes to its insertion into a small tubercle on the crest beyond. Further laterally, this border is rough, and presents two lips — a superior for the insertion of the trapezius and an inferior for the origin of the deltoid. Laterally the crest is continued into the acromion.
The spine has two sm-faces, the superior, which also looks medialward and forward, is concave, contributes to the formation of the supraspinous fossa, and gives origin to the supraspinatus muscle; the inferior surface, also slightly concave, is directed lateralward and backward, forms part of the infraspinous fossa, and affords origin to the infraspinatus muscle. On both surfaces are one or more prominent vascular foramina.
The acromion, a process overhanging the glenoid cavity, springs from the angle formed by the junction of the crest with the base of the spine. Somewhat crescentic in shape, it forms the summit of the shoulder and is compressed from above downward so as to present for examination two surfaces, two borders, and two extremities.
The posterior part sometimes terminates laterally in a prominent acromial angle (metacromion) and the process then assumes a more or less triangular form. Of the two extremities, the posterior is continuous with the spine, whilst the anterior forms the free tip. The upper surface, directed upward, backward, and slightly lateralward, is rough and convex, and affords origin at its lateral part to a portion of the deltoid; the remaining part of this surface is subcutaneous. The lower surface, directed downward, forward, and slightly medialward, is concave and smooth. The medial border, continuous with the upper lip of the crest, presents, from behind forward, an area for the insertion of the trapezius; a small, oval, concave articular facet for the lateral end of the clavicle, the edges of which are rough for the acromio-clavioular ligaments; and, beyond this, the anterior extremity or tip, to which is attached the apex of the coraco-acromial ligament. The lateral border, continuous with the inferior lip. of the crest, is thick, convex, and presents three or four tubercles with intervening depressions; from the tubercles the tendinous septa in the acromial part of the deltoid arise, and from the depressions, some fleshy fibres of the same muscle.
Projecting upward from the neck of the scapula is the coracoid process, bent finger-like,' pointing forward and laterally. It consists of two parts, ascending and horizontal, arranged at almost a right angle to each other.
The ascending part arises by a wide root, extends upward and medially for a short distance, and is compressed from before backward; it is continuous above with the horizontal part and below with the neck of the scapula; the lateral border lies above the glenoid cavity and gives attachment to the coraco-humeral ligament; the medial border, which forms the lateral boundary of the scapular notch, gives attachment to the conoid ligament above and the transverse ligament below. Its anterior and posterior surfaces are in relation with the subscapularis and supraspinatus respectively. The horizontal part of the process runs forward and lateralward; it is compressed from above downward so as to present two borders, two surfaces, and a free extremity. The medial border gives insertion along its anterior half to the pectoralis minor and nearer the base to the oosto-coracoid membrane; the lateral border is rough for the coracoacromial and coraco-humeral ligaments ;_the upper surface is irregular and gives insertion in
front to the ■pectoralis minor, and behind to the trapezoid ligament; the inferior surface is smooth and directed toward the glenoid cavity, which it overhangs; the free extremity or apex gives origin to the conjoined coraco-brachialis and short head of the biceps.
The greater part of the body of the scapula and the central parts of the spinous process are thin and transparent. The coracoid and acromion processes, the crest of the spine and inferior angle, the head, neck, and axillary border, are thick and opaque. The young bone consists of two layers of compact tissue with an intervening cancellous layer, but in the transparent parts of the adult bone the middle layer has disappeared. The vascular foramina on the costal surface transmit twigs from the subscapular and transverse scapular (suprascapular) arteries; those in the infraspinous fossa, twigs from the circumflex (dorsal) and transverse scapular (suprascapular) arteries, the latter also giving off vessels which enter the foramina in the supraspinous fossa. The acromion is supplied by branches from the thoraco-acromial (acromiothoracic) artery.
subscapular angle. From the axis three plates of bone radiate as from a centre, the prescapula forward, the mesoscapula laterally, and the postscapula backward, being named in accordance with the long axis of the body in the horizontal position. In the human subject the postscapula is greatly developed, and this is associated with the freedom and versatility of movement possessed by the upper limb.
Ossification. — The scapula is ossified from nine centres. Of these, two (for the body of the scapula and the coracoid) may be considered as primary, and the remainder as secondary. The centre for the body appears in a plate of cartilage near the neck of the scapula about the eighth week of intra-uterine life, and quickly forms a triangular plate of bone, from which the spine appears as a slight ridge about the middle of the third month. At birth the glenoid fossa and part of the scapular neck, the acromion and coracoid processes, the vertebral border and inferior angle, are cartilaginous. During the first year a nucleus appears for the coracoid, and at the tenth year a second centre appears for the base of the coracoid and the upper part of the glenoid cavity (subcoracoid, fig. 173).
During the fifteenth year the coracoid unites with the scapula, and about this time the other secondary centres appear. Two nuclei are deposited in the acromial cartilage, and fuse to form the acromion, which joins the spine at the twentieth year. The union of spine and acromion may be fibrous, hence the latter is sometimes found separate in macerated specimens. The cartilage along the vertebral border ossifies from two centres, one in the middle, and another at the inferior angle. A thin lamina is added along the upper surface of the coracoid process and
fifth year.
The occurrence of a special primary centre for the coracoid process is of morphological importance in that the process is the representative of what in the lower vertebrates is a distinct coracoid hone. This primarily takes part in the formation of the glenoid cavity and extends medially to articulate with the sternum. In man and all the higher mammals only the lateral portion of the bone persists.
Supinator
to the elbow [cubitus] below, where it articulates with the two bones of the forearm [anti-brachium]. It is divisible into a shaft and two extremities; the upper extremity includes the head [caput], neck [collum], and two tuberosities — great and small; the lower extremity includes the articular surface ^\dth the surmounting fossae in front and behind, and the two epicondyles.
THE HUMERUS
Upper extremity. — The head forms a nearly hemispherical articular surface, cartilage-clad in the recent state and directed upward, medially, and backward toward the glenoid cavity. Below the head the bone is rough and somewhat constricted, constituting the anatomical neck, best marked superiorly, where it forms a groove separating the articular surface from the two tuberosities. The circumference of the neck gives attachment to the capsule of the shoulder-joint and the gleno-humeral folds, the upper of which is received into a depression near the top of the intertubercular (bicipital) groove. The lowest part of the capsule
descends upon the humerus some distance from the articular margin. The greater tuberosity [tuberculum majus], lateral in position and reaching higher than the lesser tuberosity [tuberculum minus}, is marked by three facets for the insertion of muscles: an upper one for the supraspinatus, a middle for the in-
fraspinatiis, and a lower for the teres minor. The lesser tuberosity is situated in front of the head and is the more prominent of the two ; it receives the insertion of the subscapularis. The furrow between the tuberosities lodges the long tendon of the biceps and forms the commencement of the intertubercular (bicipital) groove, which extends downward along the shaft of the humerus. Between the tuberosities the transverse humeral ligament converts the upper end of the groove into a canal. In addition to the long tendon of the biceps and its tube of synovial
receives the pectoralis major. In the middle of the shaft it is rough and prominent and gives insertion to fibres of the deltoid; below it is smooth and rounded, giviiig origin to fibres of the brachialis, and finally it passes along lateral to the coronoid fossa to become continuous with the ridge separating the capitulum and trochlea. It separates the antero-medial from the antero-lateral surface. The lateral margin extends from the lower and posterior part of the greater tuberosity to the lateral epicondyle. Smooth and indistinct above, it gives attachment to the teres minor and the lateral head of the triceps; it is interrupted in the middle by the groove for the radial nerve (musculo-spiral groove), but the lower third becomes prominent and curved laterally to form the lateral supracondylar ridge, which affords origin in front to the brachio-radialis and the extensor carpi radialis longus; behind to the medial head of the triceps, and between these muscles in front and behind to the lateral intermuscular septum. It separates the antero-lateral from the posterior surface. The medial border commences at the lesser tuberosity, forming its crest which receives the insertion of the teres major, and continuing downward to the medial epicondyle. Near the middle of the shaft it forms a ridge for the insertion of the coraco-brachialis and presents a foramen for the nutrient artery, directed downward toward the elbow-joint. Below it forms a distinct medial supracondylar ridge, curved medially, which gives origin to the brachialis in front, the medial head of the triceps behind, and the medial intermuscular septum in the interval between the muscles. This border separates the antero-medial from the posterior surface.
Surfaces. — The antero-lateral surface is smooth above, rough in the middle, forming a large impression for the insertion of the deltoid, below which is the termination of the groove for the radial nerve. The lower part of the surface gives origin to the lateral part of the brachialis. The antero-medial surface is narrow above, where it forms the floor of the intertubercular (bicipital) groove, and receives the insertion of the latissimus dor si. Near the junction of the upper and middle thirds of the bone the groove, gradually becoming shallower, widens out and, with the exception of a rough impression near the middle of the shaft for the coraco-brachialis, the remaining part of the antero-medial surface is flat and smooth, and gives origin to the brachialis.
Occasionally, a prominent spine of bone, the supracondylar process, projects downward from the medial border about 5 cm. (2 in.) above the medial epicondyle, to which it is joined by a band of fibrous tissue. Through' the ring thus formed, which corresponds to the supracondylar foraman in many of the lower animals, the median nerve and brachial artery are transmitted, though in some cases it is occupied by the nerve alone. The process gives origin to the pronator teres, and may afford insertion to a persistent lower part of the coraco-brachialis.
The posterior surface is obliquely divided by a broad shallow groove, which runs in a spiral direction from behind downward and forward and transmits the radial (musculo-spiral) nerve and the profunda artery. The lateral part of the surface above the groove gives attachment to the lateral head, and the part below the groove, to the medial head of the triceps.
trochlea and the capitulum. The trochlea is the pulley-hke surface which extends over the end of the bone for articulation with the semilunar notch (great sigmoid cavity) of the ulna. It is constricted in the centre and expanded laterally to form two prominent edges, the medial of which is thicker, descends lower, and forms a marked projection; the lateral edge is narrow and corresponds to the interval between the ulna and radius. Above the trochlea are two fossae : on the anterior surface is the coronoid fossa, an oval pit which receives the coronoid process of
year. The upper epiphysis is
formed by the union of the nucleusfor the head, greater tuberosity, and that for the lesser tuberosity. These form a common epiphysis
third year
The centres for the radial epicondyle, trochlea, and capitulum unite together and form an epiphysis which fuses with the shaft at the seventeenth year
the ulna when the forearm is flexed; on the posterior aspect is the olecranon fossa, a deep hollow for the reception of the anterior extremity of the olecranon in extension of the forearm. These fossae are usually separated by a thin, translucent plate of bone, sometimes merely by fibrous tissue, so that in macerated specimens a perforation, the supratrochlear foramen, exists. The capitulum, or radial head, is much smaller than the trochlea, somewhat globular in shape, and limited to the anterior and inferior surfaces of the extremity. It articulates with the con-
cavity on the summit of the radius. The radial fossa is a slight depression on the front of the bone, immediately above the capitulum, which receives the anterior edge of the head of the radius in complete flexion of the forearm, whilst between the capitulum and the trochlea is a shallow groove occupied by the medial margin of the head of the radius.
In the recent state the inferior articular surface is covered with cartilage, the fossae are lined by synovial membrane, and their margins give attachment to the capsule of the elbow-joint. Projecting on either side from the lower end of the humerus are the two epicondyles. The medial one is large and by far the more prominent of the two, rough in front and below, smooth behind, where there is a shallow groove for the ulnar nerve. The rough area serves for origin of the pronator teres above, the common tendon of origin of the flexor carpi radialis, palmaris longus, flexor digitorum sublimis and flexor carpi ulnaris in the middle, and the ulnar collateral ligament below. The lateral epicondyle is flat and irregular. Above, it gives attachment to a common tendon of origin of the extensor carpi radialis brevis, extensor digitorum communis, extensor quinti digiti proprius, extensor carpi ulnaris, and supinator; to a depression near the outer margin of the capitulum, the radial collateral ligament is attached, and from an area below and behind, the anconeus takes origin.
Architecture. — The interior of the shaft of the humerus is hollowed out by a large medullary canal, whereas the extremities are composed of cancellated tissue invested by a thin compact layer. The arrangement of the cancellous tissue at the upper end of the humerus is shown in fig. 177. The lamellae converge to the axis of the bone and form a series of superimposed arches which reach upward as far as the epiphysial line. In the epiphyses the spongy tissue forms a fine network, the lamellae resulting from "pressure" being directed at right angles to the articular surface of the head and to the great tuberosity.
Blood-supply. — The foramina which cluster round the circumference of the head and tuberosities transmit branches from the transverse scapular (suprascapular) and anterior and posterior circumflex arteries. At the top of the intertubercular groove is a large nutrient foramen
appears in the third year
for a branch of the anterior circumflex artery which supplies^the head. The nutrient artery of the shaft is derived from the brachial, and in many cases, an additional branch, derived from the profunda artery, enters the foramen in the groove for the radial nerve (musculo-spiral groove) . The lower extremity is nourished by branches derived from the profunda (superior profunda) , the superior and inferior ulnar collateral (inferior profunda and anastomotic), and the recurrent branches of the radial, ulnar, and interosseous arteries.
Ossification. — The humerus is ossified from one primary centre (diaphysial) and six secondary centres (epiphysial). The centre for the shaft appears about the eighth week of intrauterine life and grows very rapidly. At birth only the two extremities are cartilaginous, and these ossify in the following manner: Single centres appear for the head in the first year, for the greater tuberosity in the third year, and for the lesser tuberosity in the fifth year, though sometimes the latter ossifies by an extension from the greater tuberosity. These three nuclei coalesce at six years to form a single epiphysis, which joins the shaft about the twentieth year.
The inferior extremity ossifies from four centres: one for the capitulum appears in the third year, a second for the medial epicondyle in the fifth year, a third for the trochlea in the tenth year, and a fourth for the lateral epicondyle in the fourteenth year. The nuclei for the capitulum, trochlea, and lateral epicondyle coalesce to form a single epiphysis which joins the shaft in the seventeenth year. The nucleus of the medial epicondyle joins the shaft independently at the age of eighteen years.
A study of the upper end of the humeral shaft before its union with the epiphysis is of interest in relation to what is known as the neck of the humerus. The term neck is appUed to three parts of this bone. The anatomical neck is the constriction to which the articular capsule is mainly attached, and its position is accurately indicated by the groove which Ues internal to the tuberosities. The upper extremity of the humeral shaft, before its union with the epiphysis , terminates in a low three-sided pyramid, the surfaces of which are separated from one another by ridges. The medial of these three surfaces underlies the head of the bone, and the two lateral surfaces underhe the tuberosities. The part supporting the head constitutes the morphological neck of the humerus, whilst the surgical neck is the indefinite area below the tuberosities where the bone is liable to fracture.
The radius (figs. 180-185) is the lateral and shorter of the two bones of the forearm. Above, it articulates with the humerus; below, with the carpus; and on the medial side with the ulna. It presents for examination a shaft and two extremities.
The upper extremity, smaller than the lower, includes the head, neck, and tuberosity. The head [capitulum], covered with cartilage in the recent state, i& a circular disc forming the expanded, articular end of the bone. Superiorly it presents the capitular depression [fovea capituli] for the reception of the capitulum
of the humerus; its circumference [circumferentia articularis], deeper on the medial aspect, articulates with the radial notch (lesser sigmoid cavity) of the ulna, and is narrow elsewhere for the annular ligament by which it is embraced. Below the head is a short cylindrical portion of bone, somewhat constricted, and known as the neck. The upper part is surrounded by the hgament which embraces the head, and below this it gives insertion antero-laterally to the supinator. Below the neck, at the antero-medial aspect of the bone, is an oval eminence, the radial tuberosity, divisible into two parts: a rough posterior portion for the insertion of
which is situated between the tendon and the tuberosity.
The body [corpus radii] or shaft is somewhat prismatic in form, gradually increasing in size from the upper to the lower end, and slightly curved so as to be concave toward the ulna. Three borders and three surfaces may be recognised. Of the borders, the medial or interosseous crest [crista interossea] is best marked. Commencing at the posterior edge of the tuberosity, its first part is round and indistinct, and receives the attachment of the oblique cord of the radius; it is con-
An aponeurosis is attached to this border from which the flexor and extensor carpi ulnaris, and flexor digitorum profundus arise
ligament
tinned as a sharp ridge which divides near the lower extremity to become continuous with the anterior and posterior margins^of the ulnar notch (sigmoid cavity). The prominent ridge and the posterior of the two lower lines give attachment to the interosseous membrane, whilst the triangular surface above the ulnar notch receives a part of the pronator quadratus. The interosseous crest separates the volar from the dorsal surface. The volar border [margo volaris] runs from the tuberosity obliquely downward to the lateral side of the bone and then descends vertically to the anterior border of the styloid process. The upper third, consti-
tuting the oblique line of the radius, gives origin to the radial head of the flexor digitorum suhlimis, limits the insertion of the supinator above, and the origin of the flexor pollicis longus below. The volar border separates the volar from the lateral surface. The dorsal border extends from the back of the tuberosity to the prominent middle tubercle on the posterior aspect of the lower extremity. Separating the lateral from the dorsal surface, it is well marked in the middle third, but becomes indistinct above and below.
Surfaces. — The volar (or anterior) surface is narrow and concave above; broad, flat, and smooth below. The upper two-thirds is occupied chiefly by the flexor pollicis longus and a little less than the lower third by the pronator quadratus. Near
the junction of the upper and middle thirds of the volar surface is the nutrient foramen, directed upward toward the proximal end of the bone. It transmits a branch of the volar interosseous artery. The lateral surface is rounded above and affords insertion to the supinator; marked near the middle by a rough, low, vertical ridge for the pronator teres; smooth below, where the tendons of the extensor carpi radialis longus and brevis lie upon it, and where it is crossed by the abductor pollicis longus and extensor pollicis brevis. The dorsal (or posterior) surface, smooth and rounded above, is covered by the supinator; grooved longitudinally in the middle third for the abductor pollicis longus and the extensor pollicis
as the posterior oblique line.
The lower extremity of the radius is quadrilateral; its carpal surface [facies articularis carpea] is articular and divided by a ridge into a medial quadrilateral portion, concave for articulation with the lunate bone; and a lateral triangular portion, extending onto the styloid process for articulation with the navicular (scaphoid) bone. The medial surface, also articular, presents the ulnar notch (sigmoid cavity) for the reception of the rounded margin of the head of the ulna. To the border separating the ulnar and carpal articular surfaces the base of the
THE ULNA
articular disc is attached, and to the anterior and posterior borders, the anterior and posterior radio-ulnar ligaments respectively. The anterior surface is raised into a prominent area for the anterior ligament of the wrist-joint. The lateral surface is represented by the styloid process, a blunt pyramidal eminence, to the base of which the hrachio-radialis is inserted, whilst the tip serves for the attachment of the radial (external) collateral ligament of the wrist. Its lateral surface is marked by two shallow furrows for the tendons of the abductor pollicis longus and extensor pollicis brevis. The posterior surface is convex, and marked by three prominent ridges separating three furrows. The posterior annular ligament is attached to these ridges, thus forming with the bone a series of tunnels for the passage of tendons.
The most lateral is broad, shallow, and frequently subdivided by a low ridge. The lateral subdivision is for the extensor carpi radialis longus, the medial for the extensor carpi radialis brevis The middle groove is narrow and deep for the tendon of the extensor pollicis longus. The most medial is shallow and transmits the extensor indicts proprius, the extensor digitorum communis, the dorsal branch of the interosseous artery, and the dorsal interosseous nerve. When the radius and ulna are articulated, an additional groove is formed for the tendon of the extensor quinti digiti proprius.
Ossification. — The radius is ossified from a centre which appears in the middle of the shaft in the eighth week of intra-uterine hfe and from two epiphysial centres which appear after birth. The nucleus for the lower end appears in the second year, and that for the upper end, which forms simply the disc-shaped head, in the fifth year. The head unites with the shaft at the seventeenth year, whilst the inferior epiphysis and the shaft join about the twentieth year.
Interosseous membn
exceeds in length by the extent of the olecranon process. It articulates at the upper end with the humerus, at the lower end indirectly \vith the carpus, and on the lateral side with the radius. It is divisible into a shaft and two extremities. The upper extremity is of irregular shape and forms the thickest and strongest part of the bone. The superior articular surface is concave from above dowTiward, convex from side to side, and transversely constricted near the middle. It belongs
partly to the olecranon, the thick upward projection from the shaft, and partly to the coronoid process, whicli projects horizontally forward from the front of the ulna. This semilunar excavation forms the semilunar notch (greater sigmoid cavity) and articulates with the trochlear surface of the humerus. The olecranon is the large curved eminence forming the highest part of the bone.
The superior surface of the olecranon, uneven and somewhat quadrilateral in shape, receives behind, where there is a rough impression, the insertion of the triceps, and along the anterior margin the articular capsule of the elbow-joint. The posterior surface, smooth and triangular in outline, is separated from the skin by a bursa. The anterior surface, covered with cartilage in the recent state, is dii'ected downward and forward, and its margins give attachment to the articular capsule of the elbow-joint. This surface, as already noticed, forms the upper and back part of the semilunar notch. On the medial surface of the olecranon is a tubercle for the origin of the ulnar head of the flexor carpi ulnaris, and in front of this a fasciculus of the ulnar collateral ligament of the elbow-joint is attached to the bone; the lateral surface is rough, concave, and gives insertion to a part of the anconeus. The extremity of the olecranon lies during extension of the elbow in the olecranon fossa of the humerus.
the twentieth year
The coronoid process, forming the lower and anterior part of the semilunar notch, has a superior articular surface continuous with the anterior surface of the olecranon, and, like it, covered with cartilage. The inferior aspect is rough and concave, and gives insertion to the brachialis.
It is continuous with the volar surface of the shaft, and near the junction of the two is a rough eminence, named the tuberosity of the ulna, which receives the attachment of the obhque cord of the radius and the insertion of the brachialis. The medial side presents above a smooth tubercle for the origin of the ulnar portion of the flexor digitorum suhlimis, and a ridge below for the lesser head of the pronator teres and the rounded accessory bundle of the flexor pollicis longus, whilst immediately behind the subhmis tubercle there is a triangular depressed surface for the upper fibres of the flexor digitorum profundus.
On the lateral surface is the radial notch (lesser sigmoid cavity), an oblong articular surface which articulates with the circumference of the head of the radius, the anterior and posterior margins of which afford attachment to the annular ligament and the radial collateral ligament of the elbow-joint. In flexion of the elbow the tip of the process is received into the coronoid fossa of the humerus.
The body [corpus ulnae] or shaft throughout the greater part of its extent is three-sided, but tapers toward the lower extremity, where it becomes smooth and rounded. It has three borders and three surfaces. Of the three borders, the lateral, the interosseous crest, is best marked. In the middle three-fifths of the shaft it is sharp and prominent, but becomes indistinct below; above it is continued by two lines which pass to the anterior and posterior extremities of the radial notch and enclose a depressed triangular area (bicipital hollow), the fore part of which lodges the tuberosity of the radius and the insertion of the biceps tendon during pronation of the hand, while from the posterior part the supinator takes origin. The interosseous crest separates the volar from the dorsal surface and gives attachment by the lower four-fifths of its extent to the interosseous membrane. The volar border is directly continuous with the medial edge of the rough surface for the brachialis and terminates inferiorly in front of the styloid process.
Semilunar notch
Throughout the greater part of its extent it is smooth and rounded, and affords origin to the flexor digitorum profundus and the pronator quadratus. It separates the volar from the medial surface. The dorsal border commences above at the apex of the triangular subcutaneous area on the back of the olecranon, and takes a sinuous course to the back part of the styloid process. The upper three-fourths gives attachment to an aponeurosis common to three muscles, viz., the flexor and extensor carpi ulnaris and the. flexor digitorum profundus. This Isorder separates the medial from the dorsal surface.
Surfaces. — The volar (or anterior) surface is grooved in the upper threefourths of its extent for the origin of the flexor digitorum profundus, narrow and convex below, for the origin of the pronator quadratus. The upper limit of the area for the latter muscle is sometimes indicated by an oblique line — the pronator ridge. Near the junction of the upper and middle thirds of the anterior surface is the nutrient foramen, directed upward toward the proximal end of the bone. It transmits a branch of the volar interosseous artery. The medial surface, smooth and rounded, gives attachment, on the upper two-thirds, to the flexor digitorwn profundus, whereas the lower third is subcutaneous. The dorsal (or posterior) surface, directed laterally as well as backward, presents at its upper part the oblique line of the ulna running from the posterior extremity of the radial notch to the dorsal border.
The oblique line gives attachment to a few fibres of the supinator and marks off the posterior surface into two unequal parts. That above the hne, much the smaDer of the two, receives the insertion of the anconeus. The more extensive part below is subdivided by a vertical ridge into a medial portion, smooth, and covered by the extensor carpi ulnaris, and a lateral portion which gives origin to three muscles, viz., the abductor pollicis longus, the extensor pollicis longus and the extensor indicis proprius, from above downward.
The lower extremity of the uhia is of small size and consists of two parts, the head and the styloid process, separated from each other on the inferior surface by a groove into which the apex of the articular disc is inserted. That part of the head adjacent to the groove is semilunar in shape and plays upon the articular disc which thus excludes the ulna from the radio-carpal or wrist-joint. The margin of the head is also semilunar, and is received into the ulnar notch of the radius. The styloid process projects from the medial and back part of the bone, and appears as a continuation of the dorsal border. To its rounded summit the ulnar collateral ligament of the wrist-joint is attached, and its dorsal surface is grooved for the passage of the tendon of the extensor carpi ulnaris. Immediately above the articular margin of the head the anterior and posterior radio-ulnar ligaments are attached in front and behind.
Ossification. — The ulna is ossified from three centres. The primary nucleus appears near the middle of the shaft in the eighth week of intra-uterine life. At birth the inferior extremity and the greater portion of the olecranon are cartilaginous. The "nucleus for the lower end appears during the fourth year and the epiphysis joins with the shaft from the eighteenth to the twentieth year. The greater part of the olecranon is ossified from the shaft, but an epiphysis is subsequently formed from a nucleus which appears in the tenth year.
The epiphysis varies in size, and may be either scale-like and form a thin plate on the summit, or involve the upper fourth of the olecranon and the corresponding articular surface. In the latter case the epiphysis is probably composed of two parts fused together: (1) The scale on the summit of the olecranon process, and (2) the beak centre which enters into the formation of the upper end of the semilunar notch (see fig. 186). The epiphysis unites to the shaft in the sixteenth or seventeenth year.
The carpus (figs. 188, 189) consists of eight bones, arranged in two rows, four bones in each row. Enumerated from the radial to the ulnar side, the bones of the proximal row are named navicular (scaphoid), lunate (semilunar), triquetral (cuneiform), and pisiform; those of the distal row, greater multangular (trapezium), lesser multangular (trapezoid), capitate (os magnum), and hamate (unciform) .
When the bones of the carpus are articulated, they form a mass somewhat quadrangular in outline, wider below than above, and with the long diameter transverse. The dorsal surface is convex and the volar surface concave from side to side. The concavity is increased by four prominences, which project forward, one
Third, ungual, or terminal phalanx
from each extremity of each row. On the radial side are the tuberosity of the navicular and the ridge of the greater multangular; on the ulnar side, the pisiform and the hook of the hamate. Stretched transversely between these prominences, in the recent state, is the transverse carpal ligament forming a canal for the passage of the flexor tendons and the median nerve into the palm of the hand. The proximal border of the carpus is convex and articulates with the distal end of the radius and the articular disc. The pisiform, however, takes no share in this articulation, being attached to the volar surface of the triquetral. The distal border forms an undulating articular surface for the bases of the metacarpal bones. The
line of articulation between the two rows of the carpus is concavo-convex from side to side, the lateral part of the navicular being received into the concavity formed by the greater multangular, lesser multangular, and capitate, and the capitate and hamate into that formed by the navicular, lunate, and triquetral bones.
digiti quinti
The individual carpal bones have several points of resemblance. Each bone (excepting the pisiform) has six surfaces, of which the anterior or volar and posterior or dorsal are rough for the attachment of ligaments, the volar surface being the broader in the proximal row, the dorsal surface in the distal row. The superior and inferior surfaces are articular, the former being generally convex and the latter concave. The lateral surfaces, when in contact with adjacent bones, are also articular, but otherwise rough for the attachment of ligaments. Further, the whole of the carpus is cartilaginous at birth and each bone is ossified from a single centre.
into two parts by a ridge running from before backward. The lateral part articulates with the greater multangular, the medial with the lesser multangular. The volar surface, rough and concave above, is elevated below into a prominent tubercle for the attachment of the transverse carpal ligament and the abductor pollicis brevis. The dorsal surface is narrow, being reduced
to a groove running the whole length of the bone; it is rough and serves for the attachment of the dorsal radio-carpal ligament. The medial surface is occupied by two articular facets, of which the upper is crescentio in shape for the lunate bone, whilst the lower is deeply concave for the reception of the head of the capitate. The lateral surface is narrow and rough for the attachment of the radial collateral ligament of the wTist-joint.
proximal row of the carpus, is markedly crescentic in outline.
The superior surface is smooth and oonve.x and articulates with the medial of the two facets on the distal end of the radius. The inferior surface presents a deep concavity divided into two parts by a line running from before backward. Of these, the lateral and larger articulates with the capitate; the medial and smaller with the hamate. The volar surface is large and convex,
the dorsal surface narrow and flat, and both are rough for the attachment of ligaments. The medial surface is marked by a smooth quadrilateral facet for the base of the triquetral. The lateral surface forms a narrow crescentic articular surface for the lunate.
For hamate
The superior surface presents laterally near the base a small, convex articular facet which plays upon the articular disc interposed between it and the distal end of the ulna, and medially a rough non-articular portion for ligaments. The inferior surface forms a large, triangular undulating facet for articulation with the hamate. The volar surface can be readily recognised by the conspicuous oval facet near the apex for the pisiform bone. The dorsal surface is rough for the attachment of ligaments. The medial and lateral surfaces are represented by the base and the apex of the pyramid. The base is marked by a flat quadrilateral facet for the lunate. The apex forms the lowest part of the bone and is roughened for the attachment of the ulnar collateral ligament of the WTist.
The Pisiform
The pisiform [os pisiform e] (fig. 193), the smallest of the carpal bones, is in many of its characters a complete contrast to the rest of the series. It deviates from the general type in its shape, size, position, use, and development.
On the dorsal surface is a single articular facet for the triquetral which reaches to the upper end of the bone, but leaves a free non-articular portion below. The volar surface, rough and rounded, gives attachment to the transverse carpal ligament, the flexor carpi ulnaris, the abductor quinti digiti, the piso-metacarpal and the piso-hamate ligaments. The median and lateral surfaces are also rough and the lateral presents a shallow groove for the ulnar artery. It is usually considered that the pisiform is a sesamoid bone developed in the tendon of the ^ea;or carpi ulnaris, though by some writers it is regarded as part of a rudimentary digit.
The Greater Multangular
The greater multangular [os multangulum ma jus] or trapezium (fig. 194), situated between the navicular and first metacarpal, is oblong in form with the lower angle prolonged downward and medially.
The superior surface is concave and directed upward and medially for articulation with the lateral of the two facets on the distal surface of the navicular, and on the inferior surface is a saddle-shaped facet for the base of the first metacarpal. The volar surface presents a prominent ridge with a deep groove on its medial side which transmits the tendon of the^exor carpi radialis. The ridge gives attachment to the transverse carpal ligament, the abductor pollicis brevis, the opponens pollicis, and occasionally a tendinous slip of insertion of the abductor pollicis longus. The dorsal and lateral surfaces are rough for ligaments. The medial surface is divided into two parts by a horizontal ridge. The upper and larger portion is concave and articulates with the lesser multangular; the lower — a small flat facet on the projecting lower angle — articulates with the base of the second metarcarpal.
The lesser multangular [os multangulum minus] or trapezoid (fig. 195), the smallest of the bones in the distal row, is somewhat wedge-shaped, with the broader end dorsally and the narrow end ventrally.
For second metacarpal
The superior surface is marked by a small, quadrilateral, concave facet, for the media of the two facets on the lower surface of the navicular. The inferior surface is convex from side to side and concave from before backward, forming a saddle-shaped articular surface for the base of the second metacarpal. Of the volar and dorsal surfaces, the former is narrow and rough.
the latter broad and rounded, constituting the widest sui-face of the bone, and both are rough for the attachment of ligaments. The lateral surface slopes downward and medially and is convex for articulation with the corresponding sm-face of the greater multangular. On the medial surface in front is a smooth flat facet for the capitate; elsewhere it is rough for ligaments. Articulations. — With the navicular above, second metacarpal below, greater multangular laterally, and the capitate medially.
The capitate [os capitatum] or os magnum (fig. 196) is the largest bone of the carpus. Situated in the centre of the wrist, the upper expanded portion, globular in shape and known as the head, is received into the concavity formed above by the navicular and lunate. The cubical portion below forms the body, whilst the intermediate constricted part is distinguished as the neck.
tacarpal
Of the six surfaces, the superior is smooth and convex, elongated from before backward for articulation with the concavity of the lunate bone. The inferior surface is divided into three unequal parts by two ridges. The middle portion, much the larger, articulates with the base of the third metacarpal; the lateral, narrow and concave, looks lateral as well as downward to articulate with the second metacarpal, whilst the medial portion is a small facet, placed on the projecting angle of the bone dorsally, for the fom'th metacarpal bone. The volar surface is convex and rough, giving origin to fibres of the oblique adductor pollicis; the dorsal surface is broad and deeply concave. Thelateral surface presents, from above downward: — (1) a smooth convex sm-face, forming the outer aspect of the head, with the superior surface of which it is continuous, for articulation with the navicular; (2) a groove representing the neck, indented for hgaments; (3) a small facet, flat and smooth, for articulation with the lesser multangular. Behind this facet is a rough area for attachment of an interosseous ligament. The medial surface has extending along its whole hinder margin an oblong articular surface for the hamate; the lower part of this smooth area sometimes forms a detached facet. The volar part of the surface is rough for an interosseous ligament.
The hamate [os hamatum] or unciform (fig. 197) is a large wedge-shaped bone, bearing a hook-like process, situated between the capitate and triquetral, with the base directed downward and resting on the two medial metacarpals.
The apex of the wedge forms the narrow superior surface, directed upward and laterally for articulation with the lunate. The inferior surface or base is divided bj' a ridge into two (juadrilateral facets for the fourth and fifth metacarpal bones. The volar svu-face is triangular in outline and presents at its lower part a prominent hamulus (unciform process), a hook-like eminence, projecting forward and curved toward the carpal canal. It is flattened from side to side so as to present two surfaces, two borders, and a free extremity. To the latter the transverse carpal ligament and the flexor carpi ulnaris (by means of the piso-hamate ligament) are attached, whilst the medial surface affords origin to the flexor brcvis and the opponens digili quinli. The lateral surface is concave and in relation to the flexor tendons. The dorsal surface is triangular and rough for ligaments. The lateral surface has extending along its upper and
hinder edges a long flat surface, wider above than below, for articulation with the capitate. In front of this articular facet the surface is rough for the attachment of an interosseous ligament. The medial surface is oblong and undulating, i. e., concavo-conve.x from base to apex, for articulation with the triquetral.
Pisiform twelfth year
Additional carpal elements are occasionally met with. The os centrale occurs normally in the carpus of many mammals, and in the human fcetus of two months it is present as a small cartilaginous nodule which soon becomes fused with the cartilage of the navicular. Failure of fusion, with subsequent ossification of the nodule, leads to the formation of an os centrale in the human carpus which is then found on the dorsal aspect, between the navicular, capitate, and lesser multangular. In most individuals, however, it coalesces with the navicular or undergoes suppression.
An additional centre of ossification, leading to the formation of an accessory carpal element, occasionally appears in connection with the greater multangular and the hamate. An accessory element {os Vesalianum) also occurs occasionally in the angle between the hamate and the fifth metacarpal, and others occur between the second and third metacarpals and the lesser multangular and capitate.
THE METACARPALS
The metacarpus (figs. 188, 189) consists of a series of five cylindrical bones [ossa metacarpalia], well described as 'long bones in miniature.' Articulated with the carpus above, they descend, slightly diverging from each other, to support the fingers, and are numbered from the lateral to the medial side. With the exception of the first, which in some respects resembles a phalanx, they conform to a general type.
A typical metacarpal bone presents for examination a shaft and two extremities. The body or shaft is prismatic and curved so as to be slightly convex toward the back of the hand. Of the three surfaces, two are lateral in position,
separated in the middle part of the shaft by a prominent palmar ridge, and concave for the attachment of interosseous muscles. The third or dorsal surface presents for examination a large, smooth, triangular area with the base below and apex above, covered in the recent state by the extensor tendons of the fingers, and two sloping areas, near the carpal extremity, also for interosseous muscles. The triangular area is bounded by two hnes, which commence below in two dorsal tubercles, and, passing upward, converge to form a median ridge situated between the sloping areas on either side. A little above or below the middle of the shaft, and near the volar border, is the medullary foramen, entering the bone obliquely upward. The base or carpal extremity, broader behind than in front, is quadrilateral, and both palmar and dorsal surfaces are rough tor hgaments; it articulates above with the carpus and on each side with the adjacent metacarpal bones. The head [capitulum] or digital extremity presents a large rounded articular surface, extending further on the palmar than on the dorsal aspect, for
The second is the longest of all the metacarpal bones, and the third, fourth, and fifth successively decrease in length. The several metacarpals possess distinctive characters by which they are readily identified.
bj' a ridge placed nearer to the medial border. The lateral portion of the surface slopes gently to the lateral border and gives attachment to the opponens poUicis; the medial portion, the smaller of the two, slopes more abruptly to the medial border, is in relation to the deep head of the flexor pollicis brevis, and presents the nutrient foramen, directed downward toward the head of the bone and transmitting a branch of the arteria princeps poUicis. The dorsal surface, wide and flattened, is in relation to the tendons of the extensor poUicis longus and brevis.
The base presents a saddle-shaped articular surface for the greater multangular, prolonged in front into a thin process. There are no lateral facets, but laterally a small tubercle receives the insertion of the abductor pollicis longus. Medially is a rough area from which fibres of the inner head of the flexor pollicis brevis take origin. The margin of the articular surface gives attachment to the articular capsule of the carpo-metacarpal joint. The inferior extremity or head is rounded and articular, for the base of the first phalanx; the greatest diameter is from side to side and the surface is less convex than the corresponding surface of the other metacarpal bones. On the volar surface it presents two articular eminences corresponding to the two sesamoid bones of the thumb. Of the two margins, the medial gives origin to the lateral head of the first dorsal interosseous, the lateral receives fibres of insertion of the opponens pollicis.
The second metacarpal (fig. 199). — The distinctive features of the four remaining metacarpals are almost exclusively confined to the carpal extremities. The second is easily recognised by its deeply cleft base. The terminal surface presents three articular facets, arranged as follows, from lateral to medial border : — (1) a small oval facet for the greater multangular; (2) a hollow for the lesser multangular; and (3) an elongated ridge for the capitate. The dorsal surface is rough for the insertions of the extensor carpi radialis longus and a part of the extensor carpi radialis brevis; the palmar surface receives the insertion of the flexor carpi radialis and gives origin to a few fibres of the oblique adductor pollicis. The lateral aspect of the extremity is rough and non-articular; the medial surface bears a bilobed facet for the third metacarpal.
metacarpal artery.
The third metacarpal (fig. 200) is distinguished by the prominent styloid process projecting upward from the lateral and posterior angle of the base. Immediately below it, on the dorsal surface, is a rough impression for the extensor carpi radialis brevis. The carpal surface is concave behind and convex in front, and articulates with the middle of the three facets on the inferior surface of the capitate. On the lateral side is a bilobed articular facet for the second metacarpal, and on the medial side two small oval facets for the fourth metacarpal. The volar a.spect of the base is rough and gives attachment to fibres of the oblique adductor pollicis and
sometimes a slip of insertion of the flexor carpi radialis. The shaft of the third metacarpal serves for the origin of the transverse adductor pollicis and two interosseous muscles. The nutrient foramen is directed upward on the radial side and transmits a branch of the second volar metacarpal artery.
The fourth metacarpal (fig. 201) has a small base. The carpal surface presents two facets: a medial, large and flat, for articulation with the hamate, and a small facet, at the lateral and posterior angle, for the capitate. On the lateral side are two small oval facets for the corresponding surfaces on the third metacarpal and a single concave facet on the medial side for the fifth metacarpal. The shaft of the fourth metacarpal gives attachment to three interosseous muscles, and the nutrient foramen, directed upward on the radial side, transmits a branch of the third volar metacarpal artery.
The fifth metacarpal (fig. 202) is distinguished by a semilunar facet on the lateral side of the base for the fourth metacarpal, and a rounded tubercle on the medial side for the extensor carpi ulnaris, in place of the usual medial facet. The carpal surface is saddle-shaped for the hamate; the palmar surface is rough for ligaments including the piso-metacarpal prolongation from the flexor carpi ulnaris. The dorsal surface of the shaft presents an oblique line separating a lateral concave portion for the fourth dorsal interosseous muscle from a smooth medial portion covered by the extensor tendons of the little finger. The palmar surface gives attachment laterally to the third palmar interosseous muscle and medially to the opponens digili quinti. The nutrient foramen is directed upward on the radial side and transmits a branch of the fourth volar metacarpal artery.
Second phalanx
or middle, and third or distal. In the thumb, the second phalanx is wanting. Arranged in horizontal rows, the phalanges of each row resemble one another and differ from those of the other two rows. In all the phalanges the nutrient canal is directed downward, toward the distal extremity.
First phalanx, — The shaft of a phalanx from the first row is flat on the palmar surface, smooth and rounded on the dorsal surface, i. e., semi-cyUndrical in shape. The borders of the palmar surface are rough for the attachment of the sheaths of the flexor tendons. The base or metacarpal extremity presents a single concave articular surface, oval in shape, for the
the base of a second phalanx.
Second phalanx. — The second phalanges are four in number and are shorter than those of the first row, which they closely resemble in form. They are distinguished, however, by the articular surface on the proximal extremity, which presents two shallow depressions, separated by a ridge and corresponding to the two condyles of the first phalanx. The distal end for the base of the third phalanx is trochlear or pulley-like, but smaller than that of the first phalanx. The palmar surface of the shaft presents on each side an impressionSfor the tendon of the flexor digitorum sublimis, and the dorsal aspect of the base is marked by a projection for the insertion of the extensor digitorum communis.
Third phalanx. — A third phalanx is readily recognised by its small size. The proximal end is identical in shape with that of a second phalanx, and bears a depression in front for the tendon of the flexor digitorum profundus. The free, flattened and expanded distal extremity presents on its palmar surface a rough semilunar elevation for the support of the pulp of the finger. The somewhat horseshoe-shaped free extremity is known as the ungual tuberosity [tuberositas unguicularis], and the bone is accordingly referred to as the ungual phalanx.
Ossification of. the Metacarpus and Phalanges
Each of the metacarpal bones and phalanges is ossified from a primary centre for the greater part of the bone, and from one epiphysial centre. The primary nucleus appears from the eighth to the tenth week of intra-uterine life. In four metacarpal bones the epiphysis is distal, whilst
in the first metacarpal bone, and in all the phalanges, it is proximal. The epiphysial nuclei appear from the third to the fifth year and are united to their respective shafts about the twentieth year. In many cases the first metacarpal has two epiphyses, one for the base in the third year and an additional one for the head in the seventh year, but the latter is never so large as in the other metacarpal bones. The third metacarpal occasionally has an additional nucleus for the prominent styloid process which may remain distinct and form a styloid bone, and traces of a proximal epiphysis have been observed in the second metacarpal bone. In many of the Cetacea (whales, dolphins, and porpoises) and in the seal, epiphyses are found at both ends of the metacarpal bones and phalanges (Flower).
The ossification of a terminal phalanx is peculiar. Like the other phalanges, it has a primary nucleus and a secondary nucleus for an epiphysis. But whereas in other phalanges the primary centre appears in the middle of the shaft, in the case of the distal phalanges the earthy matter is deposited in the free extremity.
Sesamoid Bones
The sesamoid bones are small and rounded and occur imbedded in certain tendons where they exert a considerable amount of pressure on subjacent bony structures. In the hand five sesamoid bones are of almost constant occurrence, namely, two over the metacarpo-phalangeal joint of the thumb in the tendons of the flexor pollicis brevis, one over the interphalangeal joint of the thumb, and one over the metacarpo-phalangeal joints of the second and fifth fingers.
The bones of the lower extremity may be arranged in four groups corresponding to the division of the limb into the hip, thigh, leg, and foot. In the hip is the coxal or hip-bone, which constitutes the pelvic girdle [cingulum extremitatis inferioris], and contributes to the formation of the pelvis; in the thigh is the femur; in the leg, the tibia and fibula, and in the foot the tarsus, metatarsus, and phalanges. Associated with the lower end of the femur is a large sesamoid bone, the patella or knee-cap.
The coxal (innominate) bone or hip-bone [os coxse] (figs. 205, 206) is a large, irregularly shaped bone articulated behind 'with the sacrum, and in front with its fellow of the opposite side, the two bones forming the anterior and side walls of the pelvis. The coxal bone consists of three parts, named ilium, ischium, and pubis, which, though separate in early life, are firmly united in the adult. The three parts meet together and form the acetabulum (or cotyloid fossa), a large, cup-like socket situated near the middle of the lateral surface of the bone for articulation with the head of the femur.
The ilium [os ilium] is the upper expanded portion of the bone, and by its inferior extremity forms the upper two-fifths of the acetabulum. It presents for examination three borders and two surfaces.
Borders. — When viewed from above, the thick crest [crista iliaca] or superior border is curved somewhat like the letter /, being concave medially in front and concave laterally behind. Its anterior extremity forms the anterior superior iliac spine, which gives attachment to the inguinal (Poupart's) ligament and the sartorius; the posterior extremity forms the posterior superior iliac spine and affords attachment to the sacro-tuberous (great sacro-sciatic) ligament, the posterior sacro-iliac ligament, and the multifidus. The crest is narrow in the middle, thick at its extremities, and may be divided into an inner lip, an outer lip, and an intermediate line. About two and a half inches from the anterior superior spine is a prominent tubercle on its external lip.
The external lip of the crest gives attachment in front to the tensor fascia latw; along its whole length, to the fascia lata; along its anterior half to the external oblique; and behind this, for about an inch, to the latissimus dorsi. The anterior two-thirds of the intermediate line gives origin to the internal oblique. The internal lip gives origin, by its anterior two-thirds, to the iransversus; behind this is a small area for the quadratus lumborum, and the remainder is occupied by the sacro-spinalis (erector spince). The internal lip, in the anterior two-thirds, also serves for the attachment of the iliac fascia.
The anterior border of the ilium extends from the anterior superior iliac spine to the margin of the acetabulum. Below the spine is a prominent notch from which fibres of the sartorius arise, and this is succeeded by the anterior inferior iliac spine, smaller and less prominent than the superior, to which the straight head of the rectus and the ilio-femoral ligament are attached. On the medial side of the anterior inferior spine is a broad, shallow groove for the ilio-psoas as it passes from the abdomen into the thigh, limited below by the ilio-pectineal eminence, which indicates the point of union of the ilium and pubis.
The posterior border of the ilium presents the posterior superior iliac spine, and below this, a shallow notch terminating in the posterior inferior iliac spine which corresponds to the posterior extremity of the auricular surface and gives attachment to a portion of the sacro-tuberous (great sacro-sciatic) hgament. Below the spine the posterior border of the ilium forms the upper limit of the greater sciatic notch.
The posterior gluteal line commences at the crest about two inches from the posterior superior iliac spine and curves downward to the upper margin of the greater sciatic notch. The space included between this ridge and the crest affords origin at its upper part to the gluteus maximus, and at its lower part, to a few fibres of the piriformis, while the intermediate portion is smooth and free from muscular attachment. The anterior gluteal line begins at the crest, one inch behind its anterior superior iliac spine, and curves across the dorsum to terminate near the lower end of the superior line, at the upper margin of the greater sciatic notch. The surface of bone between this line and the crest is for the origin of the gluteus medius. The inferior gluteal line commences at the notch immediately below the anterior
Ramus of ischium Obturator externus
superior iliac spine and terminates posteriorly at the front part of the greater sciatic notchThe space between the anterior and inferior gluteal lines, with the exception of a small area adjacent to the anterior end of the spine for the tensor fasciw latce, gives origin to the gluteus minimus. Between the inferior gluteal line and the margin of the acetabulum the surface affords attachment to the capsule of the hip-joint, and on a rough area (sometimes a depression) toward its anterior part, to the reflected tendon of the rectus femoris.
The internal surface presents in front a smooth concave portion termed the iliac fossa, which lodges the iliacus muscle. The fossa is limited below by linea arcuata, the iliac portion of the terminal (iho-pectineal) line. This is a rounded border separating the fossa from a portion of the internal surface below the line, which gives attachment to the obturator internus and enters into the formation of the minor (true) pelvis. Behind the iliac fossa the bone is uneven and presents
an auricular surface, covered with cartilage in the recent state, for articulation with the lateral aspect of the upper portion of the sacrum; above the auricular surface are some depressions for the posterior sacro-iliac ligaments and a rough area reaching as high as the crest, from which parts of the sacro-spinalis {erector spince) and vmltifidus take origin. The rough surface above the auricular facet is known as the tuberosity of the ilium.
cavernosas membranacese
the formation of the acetabulum, to which it contributes a little more than twofifths, and forms the chief part of the non-articular portion or floor. The inner surface forms part of the minor (true) pelvis and gives origin to the obturator in ternus. It is continuous with the ilium a little below the terminal (ilio-pectineal) line, and with the pubis in front, the line of junction with the latter being frequently indicated in the adult bone by a rough line extending from the ilio-pectineal eminence to the margin of the obturator foramen. The outer surface in eludes the portion of the acetabulum formed by the ischium. The posterior surface is broad and bounded laterally by the margin of the acetabulum and behind
by the posterior border. The capsule of the hip-j oint is attached to the lateral part and the -pirijorniis, the great sciatic and posterior cutaneous nerves, the inferior gluteal (sciatic) artery, and the nerve to the quadratus femoris lie on the surface as they leave the pelvis. Inferiorly this surface is limited by the obturator groove, which receives the posterior fleshy border of the obturator externus when the thigh is flexed. Of the three borders, the external, forming the prominent rim of the acetabulum, separates the posterior from the external surface and gives attachment to the glenoid lip. The inner border is sharp and forms the lateral boundary of the obturator foramen. The posterior border is continuous with the posterior border of the ilium, with which it joins to complete the margin of the great sciatic notch [incisura ischiadica major]. The notch is converted into a foramen by the sacro-spinous (small sacro-sciatic) ligament, and transmits the piriformis muscle, the gluteal vessels, the superior and inferior gluteal nerves, the sciatic and posterior cutaneous nerves, the internal pudic vessels and nerve, and the nerves to the obturator internus and quadratus femoris. Below the notch is the prominent ischial spine, which gives attachment internally to the coccygeus and levator ani, externally to the gemellus superior, and at the tip to the sacrospinous ligament. Below the spine is the small sciatic notch [incisura ischiadica minor], covered in the recent state with cartilage, and converted into a foramen by the sacro-tuberous (great sacro-sciatic) ligament. It transmits the tendon of the obturator internus, its nerve of supply, and the internal pudic vessels and nerve.
The rami form the flattened part of the ischium which runs first downward, then upward, forward and medially from the tuberosity toward the inferior ramus of the pubis, with which it is continuous. The rami together form an Lshaped structure with an upper vertical ramus [ramus superior] and a lower horizontal ramus [ramus inferior]. The outer surface of the rami gives origin to the adductor magyius and obturator externus; the inner surface, forming part of the anterior wall of the pelvis, receives the crus penis (or clitoridis) and the ischiocavernosus, and gives origin to a part of the obturator internus. Of the two borders, the upper is thin and sharp, and forms part of the boundary of the obturator foramen; the lower is rough and corresponds to the inferior ramus. It is somewhat everted and gives attachment to the fascia of Colles, and the transversus perinei. To a ridge immediately above the impression for the cms penis (or clitoridis) and the ischio-cavernosus , the urogenital trigone (triangular ligament) is attached. The posterior and inferior aspect of the superior ramus is an expanded area forming the tuberosity [tuber ischiadicum].
The tuberosity is that portion of the ischium which supports the body in the sitting posture. It forms a rough, thick eminence continuous with the inferior border of the infeiior ramus, and is marked by an oblique line separating two impressions, an upper and lateral for the semimembranosus, and a lower and medial for the common tendon of the biceps and semitendinosus, while the lower part is markedly uneven and gives origin to the adductor magnus. The upper border gives origin to the inferior gemellus; the inner border, sharp and. prominent, receives the sacro-tuberous (great sacro-sciatic) ligament, while the surface of the tuberosity immediately in front is in relation with the internal pudic vessels and nerve. The outer border gives origin to the quadratus femoris.
The pubis [os pubis] consists of a body and two rami — superior and inferior. The body is somewhat quadrilateral in shape and presents for examination two surfaces and three borders. The anterior surface looks downward, forward and slightly outward, and gives origin to the adductor longus, the adductor brevis, the obturator externus, and the gracilis. The posterior surface is smooth, looks into the pelvis, and affords origin to the levator ani, the obturator internus, and the puboprostatic ligaments. The upper border or crest of the body is rough and presents laterally a prominent bony point, known as the tubercle [tuberculum pubicum] or spine, for the attachment of the inguinal (Poupart's) ligament. The upper border extends from the pubic tubercle medialward to the upper end of the symphysis, with which it forms the angle of the pubis. The upper border is a short horizontal ridge, which gives attachment to the rectus abdominis and pyramidalis. The medial border is oval in shape, rough, and articular, forming with the bone of the opposite side the symphysis pubis [facies symphyseos]. The lateral border is sharp and forms part of the boundary of the obturator foramen.
ment to the gracilis.
The superior ramus extends from the body of the pubis to the ilium, forming by its lateral extremity the anterior one-fifth of the articular surface of the acetabulum. It is prismatic in shape and increases in size as it passes laterally. Above it presents a sharp ridge, the pecten or pubic portion of the terminal (ilio-pectineal) line continuous with the iliac portion at the ilio-pectineal eminence, and affording
attachment to the conjoined tendon [falx aponeurotica inguinalis], the lacunar (Gimbernat's) hgament, the reflected inguinal ligament (fascia triangularis), and the pubic portion of the fascia lata; the ihac portion of the terminal (iliopectineal) line gives attachment to the psoas minor, the iliac fascia, and the pelvic fascia. Immediately in front of the pubic portion of the line is the pectineal surface; it gives origin at its posterior part to the pectineus, and is limited below by the obturator crest, which extends from the pubic tubercle to the acetabular notch. The inferior surface of the ascending ramus forms the upper boundary of the obturator foramen and presents a deep groove [sulcus obturatorius] for the passage of the obturator vessels and nerve. The posterior surface is smooth, forms part of the anterior wall of the pelvic cavity, and gives attachment to a few fibres of the obturator internus.
According to the BNA, the body [corpus ossis pubis] is the portion corresponding to the acetabulum. The remainder of the bone is described as consisting of the ramus superior and the ramus inferior, which meet at the symphysis. Thus the divisions according to the BNA are different from those in the description above given.
The acetabulum is a circular depression in which the head of the femur is lodged and consists of an articular and a non-articular portion. The articular portion is circumferential and semilunar in shape [facies lunata], with the deficiency in the lower segment. One-fifth of the acetabulum is formed bj^ the pubis, two-fifths by the ischium, and the remaining two-fifths are formed by the ilium. In rare instances the pubis may be excluded by a fourth element, the cotyloid bone. The non-articular portion [fossa acetabuli] is formed mainly by the ischium, and is continuous below with the margin of the obturator foramen. The articular portion presents a lateral rim to which the glenoid lip is attached, and a medial margin to which the synovial membrane which excludes
the ligamentum teres from the synovial cavity is connected. The opposite extremities of the articular lunate surface which limit the acetabular notch are united by the transverse ligament, and through the acetabular foramen thus formed a nerve and vessels enter the joint.
The obturator (thyreoid) foramen is sHuated between the ischium and pubis. Its margins are thin, and serve for the attachment of the obturator membrane. At the upper and posterior angle it is deeply grooved for the passage of the obturator vessels and nerve.
CoxAL Bones.
The nucleus for the pubis appears bout the end of the fourth month 3 nucleus for the ischium appears Q the third month
Blood-supply. — The chief vascular foramina of the coxal bone are found where the bone is thickest. On the inner surface, the ilium receives twigs from the ilio-lumbar, deep circumflex iliac, and obturator arteries, by foramina near the crest, in the iliac fossa, and below the terminal line near the greater sciatic notch. On the outer surface the chief foramina are found below the inferior gluteal line and the nutrient vessels are derived from the gluteal arteries. The ischium receives nutrient vessels from the obturator, internal and external circumflex arteries, and the largest foramina are situated between the acetabulum and the ischial tuberosity. The pubis is supplied by twigs from the obturator, internal and external circumflex arteries, and from the pubic branches of the common femoral artery.
Fuses at twenty
Ossification. — The cartilaginous representative of the hip-bone consists of three distinct portions, an iliac, an ischiatic, and a pubic portion; the iliac and ischiatio portions first unite and later the pubic portion, so that eventually there is found a single cartilaginous mass. Early in the second month a centre of ossification appears above the acetabulum for the ilium. A little later a second nucleus appears below the cavity for the ischium, and this is followed in the fourth month by a deposit in the pubic portion of the cartilage. At birth, the three nuclei
THE PELVIS
are of considerable size, but are surrounded by relatively wide tracts of cartilage; ossification has, however, extended into the margin of the acetabulum. In the eighth j^ear the rami of the pubis and ischium become united by bone, and in the tweKth year the triradiate cartilage which separates the three segments of the bone in the acetabulum begins to ossify from several centres. Of these, one is more constant than the others and is known as the acetabular nucleus. The triangular piece of bone to which it gives rise is regarded as the representative of the cotyloid or acetabular bone, constantly present in a few mammals. It is situated at the medial part of the acetabulum and is of such a size as to exclude entirely the pubis from the cavity. With this bone, however, it eventually fuses, and afterward becomes joined with the ilium and
ischium, so that by the eighteenth or twentieth year the several parts of the acetabulum have become united. In the fifteenth year other centres appear in the cartilage of the crest of the ilium, the anterior inferior iliac spine, the tuberosity of the ischium, and the pubic pecten. The epiphyses fuse with the main bone about the twentieth year. The fibrous tissue connected with the tubercle of the pubis represents the epipubio bones of marsupials.
The pelvis (figs. 211, 212, 213, 214) is composed of four bones: the two coxal or hip-bones, the sacrum, and the coccyx. The hip-bones form the lateral and anterior boundaries, meeting each other in front to form the pubic symphysis [symphysis ossium pubis]; posteriorly they are separated by the sacrum. The interior of the pelvis is divided into the major and minor pelvic cavity.
The major (or false) pelvis is that part of the cavity which lies above the terminal (ihopectineal) lines and between the iliac fossse. This part belongs really to the abdomen, and is in relation with the hypogastric and iliac regions.
The minor (or true) pelvis is situated below the terminal (ilio-pectineal) lines. The upper circumference, known as the superior aperture (inlet or brim) of the pelvis, is bounded anteriorly by the tubercle and pecten of the pubis on each side, posteriorly by the anterior margin of the base of the sacrum, and laterally by the terminal lines. The inlet in normal pelves is heart-shaped, being obtusely pointed in front; posteriorly it is encroached upon by the promontory of the sacrum. It has three principal diameters; of these, the antero-posterior, called the conjugate diameter [conjugata], is measured from the sacro-vertebral angle to the symphj^sis. The transverse diameter represents the greatest width of the pelvic cavity. The oblique diameter is measured from the sacro-iliac synchondrosis of one side to the ilio-pectineal eminence of the other.
The cavity of the minor (true) pelvis is bounded in front by the pubes, behind bjr the sacrum and coccj^x, and laterally by a smooth wall of bone formed in part by the ilium and in part by the ischium. The cavity is shallow in front, where it is formed by the pubes, and is deepest posteriorly.
The inferior aperture, or outlet, of the minor pelvis is verj' irregular, and encroached upon by three bony pi'ocesses: the posterior process is the coccyx, and the two lateral processes are the ischial tuberosities. They separate three notches. The anterior notch is the pubic arch, and is bounded on each side by the conjoined rami of the pubes and ischium. Each of the two remaining gaps, bounded by the
ischium anteriorly, the sacrum and coccjrx posteriorly, and the ilium above, corresponds to the greater and lesser sciatic notches. These are converted into foramina bj^ the sacro-tuberous (great sacro-sciatic) and sacro-spinous (small sacro-sciatic) ligaments.
given.
Differences according to sex. — There is a marked difference in the size and form of the male and female pelvis, the pecularities of the latter being necessary to qualify it for its functions in partm-ition. The various points of divergence may be tabulated as follows: —
Symphysis deeper.
Tuberosities of ischia inflexed. Pubic angle narrow and pointed. Margins of ischio-pubic rami more everted. Obturator foramen oval.
Tuberosities of ischia everted. Pubic arch wider and more rounded. Margins of ischio-pubic rami less everted. Obturator foramen triangular.
fourth month of fcetal life.
Quite recently attention has been drawn by D. Derry to some special points in which the OS coxaj differ in the two sexes, and two figures are shown here in which one of these points is clearly brought out. It will be seen that the great sciatic notch is larger in the female, and that the sacrum projects less forward at its apex. Moreover the facies auricularis is smaller whilst below and in front of this surface, the sulcus preauricularis, a depression for the attachment of the ligamenta sacroiliaca anteriora, is usualh- more pronounced.
In comparison with the pelves of lower animals, which, speaking generally, are elongated and narrow, the human pelvis is characterised by its breadth, shallowness, and great capacity. Differences are also to be recognised in the form of the pelvis in the various races of mankind, the most important being the relation of the antero-posterior to the transverse diameter, measured
transverse diameter
In the average European male the index is about 80; in the lower races of mankind, 90 to 95. Pelves with an index below 90 are platypellic, from 90 to 95 are mesatipellic, and above 95 dolichopellic. (Sir WiUiam Turner.)
THE FEMUR
The femur or thigh bone (figs. 215, 216) is the largest and longest bone in the skeleton, and transmits the entire weight of the trunk from the hip to the tibia. In the erect posture it inclines from above downward and medially, approaching at the lower extremity its fellow of the opposite side, but separated from it above by the width of the true pelvis. It presents for examination a superior extremity, including the head, neck, and two trochanters, an inferior extremity, expanded laterally into two condyles, and a shaft.
The upper extremity is surmounted by a smooth, globular portion called the head, forming more than half a sphere, directed upward and medially for articulation with the acetabulum. With the exception of a small rough depression, the fovea, for the ligamentum teres, a little below and behind the centre of the head, . its surface is covered with cartilage in the recent state. The head is connected with the shaft by the neck, a stout rectangular column of bone which forms with the shaft, in the adult, an angle of about 125*. Its anterior surface is in the same plane with the front aspect of the shaft, but is marked off from it by a ridge to which the capsule of the hip-joint is attached. The ridge, which commences at the great trochanter in a small prominence, or tubercle, extends obliquely downward, and winding to the back of the femur, passes by the lesser trochanter and becomes continuous with the medial lip of the linea aspera, on the posterior aspect of the shaft. This ridge forms the intertrochanteric line or spiral line of the femur. The intertrochanteric line receives the bands of the ilio-femoral thickening of the capsule of the hip-joint. The posterior surface of the neck is smooth and concave and its medial two-thirds is enclosed in the capsule of the hip-joint. The superior border of the neck, perforated by large nutrient foramina, is short and thick, and runs downward to the great trochanter. The inferior border, longer and narrower than the superior, curves downward to terminate at the lesser trochanter.
The great trochanter is a thick, quadrilateral process surmounting the junction of the neck with the shaft, and presents for examination two surfaces and four borders. The lateral surface is broad, rough, and continuous with the lateral surface of the shaft. It is marked by a diagonal ridge running from the posterosuperior to the antero-inferior angle, which receives the insertion of the gluteus medius. The ridge divides the surface into two triangular areas : an upper, covered by the gluteus medius, and occasionally separated from it by a bursa, and a lower, covered by a bursa to permit the free gliding of the tendon of the gluteus maximus. Of the medial surface the lower and anterior portion is joined with the rest of the bone; the upper and posterior portion is free, concave, and presents a deep depression, the trochanteric or digital fossa, which receives the tendon of the obturator externus. The fore part of the surface is marked by an impression for the insertion of the obturator internus and two gemelli.
Of the four borders, the superior, thick and free, presents near the centre an oval mark for the insertion of the -piriformis; the anterior border, broad and irregular, receives the gluteus minimus; the posterior border, thick and rounded, is continuous with the intertrochanteric crest, the prominent ridge uniting the two trochanters behind. Above the middle of this line is an elevation, termed the tubercle of the quadratus, for the attachment of the upper part of the quadralus femoris. The inferior border corresponds with the line of junction of the base of the trochanter with the shaft; it is marked by a prominent ridge for the origin of the upper part of the vastus lateralis.
The lesser trochanter is a conical eminence projecting medially from the posterior and mecUal aspect of the bone, where the neck is continuous with the shaft. Its summit is rough and gives attachment to the tendon of the ilio-psoas. The fibres of the iliacus extend beyond the trochanter and are inserted into the surface of the shaft immediately below.
The body or shaft of the femur is almost cylindrical, but is slightly flattened in front and strengthened behind by a projecting longitudinal ridge, the linea aspera, for the origin and insertion of muscles. The linea aspera extends along the middle third of the shaft and presents a medial lip and a lateral lip separated by a narrow interval. When followed into the upper third of the shaft, the three parts diverge. The lateral lip becomes continuous with the gluteal tuberosity and ends at the base of the great trochanter. The ridge affords insertion to the gluteus maximus,
and when very prominent is termed the third trochanter. The medial Hp curves medialward below the lesser trochanter, where it becomes continuous with the intertrochanteric line; the intervening portion bifurcates and is continued upward as two lines, one of which ends at the small trochanter, and receives some fibres of the iliacus, whilst the other is the linea pectinea and marks the insertion of the pectineus muscle.
Toward the lower third of the shaft the medial and lateral lips of the linea aspera again diverge, and are prolonged to the condyles by the medial and lateral supra-condylar lines, enclosing between them a triangular surface of bone, the popliteal surface [planum popliteum] of the femur, which forms the upper part of the floor of the popliteal space. The lateral line is the more prominent and terminates below in the lateral epicondyle. The medial one is interrupted above, where the femoral vessels are in relation with the bone, better marked below, where it terminates in the adductor tubercle, a small sharp projection at the summit of the medial epicondyle, which affords attachment to the tendon of the adductor magnus.
toward the head of the bone.
From the medial lip of the linea aspera and the lower part of the int-ertrochanteric line arises the vastus medialis (internus), and from the lateral lip and the side of the gluteal ridge arises the vastus lateralis (externus). The adductor magnus is inserted into the medial lip of the linea aspera, from the medial side of the gluteal tuberosity above, and the medial supracondylar line below. Between the adductor magnus and vastus medialis (internus) four muscles are attached: the pectineus and iliacus above, then the adductor brevis, and lowest of all, the adductor longus. Above, in the interval between the adductor magnus and the vastus lateralis (externus), the gluteus maximus is inserted; in the interval lower down is the short head of the biceps, taking origin from the lower two-thirds of the lateral] lip of the linea aspera and the upper two-thirds of the lateral supra-condylar line. On the popliteal surface of the bone, just above the condyles, are two rough areas from which fibres of the two heads of the gastrocnemius take origin. Above the area for the lateral head of the gastrocnemius is a slight roughness for the plantaris.
For purposes of description it is convenient to regard the shaft of the femur as presenting anterior, medial, and lateral surfaces, although definite borders separating the surfaces from one another do not exist. All three surfaces are smooth and the anterior is not separated from the lateral by ridges of any kind. In the middle third of the shaft the medial and lateral surfaces approach one another behind, being separated by the linea aspera.
The shaft is overlapped on its medial side by the vastus medialis (internus) , and on its lateral side by tlie vastus lateralis (externus). The upper three-fourths of the anterior and lateral surfaces afford origin to the vastus intermedius (crureus), and the lower fourth of the anterior surface, to the articularis genu (sub-crureus) . The medial surface is free from muscular attachment.
The lower extremity presents two cartilage-covered eminences or condyles, separated behind by the intercondyloid fossa. The lateral condyle is wider than its fellow and more prominent anteriorly; the medial condyle is narrower, more prominent, and longer, to compensate for the obliquity of the shaft. When the femur is in the natural position, the inferior surfaces of the condyles are on the
same plane, and almost parallel, for articulation with the upper surfaces on the head of the tibia. The two condyles are continuous in front, forming a smooth trochlear surface [facies patellaris] for articulation with the patella. This surface presents a median vertical groove and two convexities, the lateral of which is wider, more prominent, and prolonged farther upward. The patellar surface is faintly marked off from the tibial articular surfaces by two irregular grooves, best seen while the lower end is still coated with cartilage. The lateral groove commences on the medial margin of the lateral condyle near the front of the intercondylar fossa, and extends obliquely forward to the lateral margin of the bone. The general direction of the medial groove is from front to back, turning medially in front and extending backward as a faint ridge which marks off from the
rest of the medial condyle a narrow semilunar facet for articulation with the medial perpendicular facet of the patella in extreme flexion. The grooves receive the semilunar menisci in the extended position of the joint. The tibial surfaces are almost parallel except in front, where the medial turns laterally to become continuous with the patellar surface.
The opposed surfaces of the two condyles form the boundaries of the intercondylar fossa and give attachment to the crucial ligaments which are lodged within it. The posterior crucial ligament is attached to the fore part of the lateral surface of the medial condyle and the anterior crucial ligament to the back part of the medial surface of the lateral condyle. The two remaining surfaces of the condyles are broad and convex, and each presents an epicondyle (tuberosity) for the attachment of lateral ligaments. The medial epicondyle, the larger of the two, is surmounted by the adductor tubercle, behind which is an impression for
the medial head of the gastrocnemius on the upper aspect of the condyle; below and behind the lateral epicondyle is a deep groove which receives the tendon of the popliteus muscle when the knee is flexed, and its anterior end terminates in a pit from which the tendon takes origin. Above the lateral epicondyle is a rough impression for the lateral head of the gastrocnemius.
The interior of the shaft of the femur is hollowed out by a large medullary canal, and the extremities are composed of cancellated tissue invested by a thin compact la3'er. The arrangement of the cancelli in the upper end of the bone forms a good illustration of the effect produced by the mechanical conditions to which bones are subject. In the upper end of the bone the cancellous tissue is arranged in divergent curves. One system springs from the lower part of the neck and upper end of the shaft medially and spreads into the great trochanter ('pressure lamellae'). A second system springs from the lateral part of the shaft and arches upward into the neck and head ('tension lamelte'), crossing the former almost at right angles. A second set of pressure lamellae springs from the lower thick wall of the neck, and extends into the upper part of the head to end perpendicularly in the articular surface mainly along the lines of greatest pressure. A nearly vertical plate of compact tissue (calcar femorale) projects into the neck of the bone from the inferior cervical tubercle toward the great trochanter. This is placed in the line through which the weight of the body falls, and adds to the stability of the neck of the bone; it is said to be liable to absorption in old age. In the lower end of the bone the vertical and horizontal fibres are so disposed as to form a rectangular meshwork.
Blood-supply. — The head and neck of the femur receive branches from the inferior gluteal, obturator, and circumflex arteries, and the trochanters from the circumflex arteries. The nutrient vessel of the shaft is derived from either the second or third perforating artery, or there may be two nutrient vessels arising usually from the first and third perforating. The vessels of the inferior extremity arise from the articular branches of the popliteal and the anastomotic branch of the femoral (supremagenu).
Ossification. — The femur is ossified from one primary centre for the shaft and from four epiphysial centres. The shaft begins to ossify in the seventh week of intra-uterine life. Early in the ninth month a nucleus appears for the lower extremity. During the first year the nucleus for the head of the bone is visible, and in the fourth year that for the trochanter major. The centre for the lesser trochanter appears about the thirteenth or fourteenth year. The lesser trochanter joins the shaft at the seventeenth, the great trochanter at the eighteenth, the head about the nineteenth, and the lower extremity at the twentieth year.
the condylar epiphysis with the shaft passes through the adductor tubercle.
The morphological relation of the patellar facet to the tibial portions of the condyles is worthy of notice. In a few mammals, such as the ox, this facet remains separated from the condyles by a furrow of rough bone,
The angle which the neck of the femur forms with the shaft at birth measures, on an average, 160°. In the adult it varies from 110° to 140°; hence the angle decreases greatly during the period of growth. When once growth is completed, the angle, as a rule, remains fixed. (Humphry.)
The patella (fig. 222) or knee-pan, situated in front of the knee-joint, is a sesamoid bone, triangular in shape, developed in the tendon of the quadriceps femoris. Its anterior surface, marked by numerous longitudinal striae, is slightly convex, and
perforated by small openings which transmit nutrient vessels to the interior of the bone. It is covered in the recent state by a few fibres prolonged from the common tendon of insertion (supra-patellar tendon) of the quadriceps femoris, into the ligamentum patellae (infra-patellar tendon), and is separated from the skin by one
THE TIBIA 185
or more bursse. The posterior surface is largely articular, covered with cartilage in the recent state, and divided by a slightly marked vertical ridge, corresponding to the groove on the trochlear surface of the femur, into a lateral larger portion for the lateral condyle, and a medial smaller portion for the medial condyle. Close to the medial edge a faint vertical ridge sometimes marks off a narrow articular facet, for the lateral margin of the medial condyle of the femur in extreme flexion of the leg. Below the articular surface is a rough, non-articular depression, giving attachment to the ligamentum patellae, and separated by a mass of fat from the head of the tibia.
Anterior surface
tendon of the quadriceps. The borders, thinner than the base, converge to the apex below, and receive parts of the two vasti muscles. The apex forms a blunt point directed downward, and gives attachment to the ligamentum patellae, by which the patella is attached to the tibia.
Structurally the patella consists of dense cancellous tissue covered by a thin compact layer, and it receives nutrient vessels from the articular branch of the suprema genu (anastomotic), the anterior tibial recurrent, and the inferior articular branches of the popliteal.
Ossification. — The cartilaginous deposit in the tendon of the quadriceps muscle takes place in the fourth month of intra-uterine life. Ossification begins from a single centre during the third year, and is completed about the age of puberty.
The tibia (figs. 224, 225) or shin-bone is situated at the front and medial side of the leg and nearly parallel with the fibula. Excepting the femur, it is the largest bone in the skeleton, and alone transmits the weight of the trunk to the foot. It articulates above with the femur, below \vith the tarsus, and laterally with the fibula. It is divisible into two extremities and a shaft.
The upper extremity (or head) consists of two lateral eminences, or condyles. Their superior articular surfaces receive the condyles of the femur, the articular parts being separated by a non-articular interval, to which ligaments are attached. The medial articular surface is oval in shape and concave for the medial condyle of the femur. The lateral articular surface is smaller, somewhat circular in shape, and presents an almost plane surface for the lateral condyle. The peripheral portion of each articular surface is overlaid by a fibro-cartilaginous meniscus of semilunar shape, connected with the margins of the condyles by bands of fibrous tissue termed coronary ligaments. Each semilunar meniscus is attached firmly to the rough interval separating the articular surfaces. This interval is broad and depressed in front, the anterior intercondyloid fossa, where it affords attachment to the anterior extremities of the medial and lateral menisci and the anterior crucial ligament; elevated in the middle to form the intercondyloid eminence or spine of the tibia, a prominent eminence, presenting at its summit two compressed intercondyloid tubercles, on to which the condylar articular surfaces are prolonged ; the posterior aspect of the base of the eminence affords attachment to the posterior extremities of the lateral and medial semilunar menisci, and limits a deejj notch, inclined toward the medial condyle, known as the posterior intercondyloid fossa or popliteal notch. It separates the condyles on the posterior aspect of the head and gives attachment to the posterior crucial ligament, and part of the posterior ligament of the knee-joint. Anteriorly, the two condyles are confluent, and form a somewhat flattened surface of triangular outline, the apex of which forms the tuberosity of the tibia. The tuberosity is divisible into two parts. The upper
part, rounded and smooth, receives the attachment of the ligamentum patellse. The lower part is rough, and into its lateral edges prolongations of the ligamentum patella are inserted. A prominent bursa intervenes between the ligament and the anterior aspect of the upper extremity of the bone.
The medial condyle is less prominent though more extensive than the lateral, and near the posterior part of its circumference is a deep horizontal groove for the attachment of the central portion of the semimembranosus tendon. The margins of this groove, and the surface
of bone below, give attachment to the tibial (internal) lateral ligament of the knee. On the under aspect of the lateral condyle is a rounded articular facet for the head of the fibula, flat and nearly circular in outline, directed downward, backward, and laterally. The circumference of the facet is rough and gives attachment to the ligaments of the superior tibio-fibular joint, while above and in front of the facet, at the junction of the anterior and lateral surfaces
The shaft or body [corpus] of the tibia, thick and prismatic above, becomes thinner as it descends for about two-thirds of its length, and then gradually expands toward its lower extremity. It presents for examination three borders and three surfaces. The anterior border is very prominent and known as the anterior crest of the tibia. It commences above on the lateral edge of the tuberosity and terminates below at the anterior margin of the medial malleolus. It runs a somewhat sinuous course, and gives attachment to the deep fascia of the leg. The medial border extends from the back of the medial condyle to the posterior margin of the medial malleolus, and affords attachment above, for about three inches, to
the tibial (internal) lateral ligament of the knee-joint and in the middle third, to the soleus. The interosseous crest or lateral border, thin and prominent, gives attachment to the interosseous membrane. It commences in front of the fibular facet, on the upper extremity, and toward its termination bifurcates to enclose a triangular area for the attachment of the interosseous ligament uniting the lower ends of the tibia and fibula.
The medial surface is bounded by the medial margin and the anterior crest; it is broad above, where it receives the insertions of the sartorius, gracilis, and semitendinosus; convex and subcutaneous in the remainder of its extent. The lateral surface lies between the crest of the tibia and the interosseous crest. The upper two-thirds presents a hollow for the origin of the tibialis anterior; the rest of the
surface is convex and covered by the extensor tendons and the anterior tibial vessels. The posterior surface is limited by the interosseous crest and the medial border. The upper part is crossed obliquely by a rough popliteal line, extending from the fibular facet on the lateral condyle to the medial border, a little above the middle of the bone.
The popliteal line gives origin to the soleus and attachment to the popliteal fascia, while the triangular surface above is occupied by the popliieus muscle. Descending along the posterior surface from near the middle of the popliteal line is a vertical ridge, well marked at its commencement, but gradually becoming indistinct below. The portion of the surface between the ridge and the medial border gives origin to the flexor digilorum longus; the lateral and narrower part, between the ridge and the interosseous border, to fibres of the tibialis posterior. The lower third of the posterior surface is covered by flexor tendons and the posterior tibial vessels. Immediately below the popliteal line and near the interosseous border is the large medullary foramen directed obliquely downward.
The lower extremity, much smaller than the upper, is quadrilateral in shape and presents a strong process called the medial malleolus, projecting downward from its medial side. The anterior surface of the lower extremity is smooth and rounded above, where it is covered by the extensor tendons, rough and depressed below for the attachment of the anterior ligament of the ankle-joint. It sometimes bears a facet for articulation with the neck of the talus (astragalus) . (A. Thomson.) The posterior surface is rough and is marked by two grooves. The medial and deeper of the two encroaches on the malleolus, and receives the tendons of the tibialis posterior and flexor digitorum longus; the lateral, very shallow and sometimes indistinct, is for the tendon of the flexor hallucis longus. The lateral surface is triangular and hollowed for the reception of the lower end of the fibula and rough for the interosseous ligament which unites the two bones, except near the lower border, where there is usually a narrow surface, elongated from before backward, covered with cartilage in the recent state for articulation with the fibula. The lines in front of and behind the triangular surface afford attachment to the anterior and posterior ligaments of the inferior tibio-fibular articulation. The medial surface, prolonged downward on the medial malleolus, is rough, convex, and subcutaneous. The lateral surface of this process is smooth and articulates with the facet on the medial side of the talus (astragalus). Its lower border is notched, and from the notch, as well as from the tip and anterior border, the fibres of the deltoid Hgament of the ankle-joint descend. The inferior or terminal surface, by which the tibia articulates with the talus, is of quadrilateral form, concave from before backward, wider in front than behind, and laterally than medially where it is continuous with the lateral surface of the malleolus.
The occasional facet on the anterior siu'face of the lower extremity of the tibia is a pressure facet, produced by extreme flexion of the ankle joint. It is therefore sometimes designated as the squatting facet." (See fig. 333.)
Blood-supply. — The tibia is a very vascular bone. The nutrient artery of the shaft is furnished by the posterior tibial, and is the largest of its kind in the body. The head of the bone receives numerous branches from the inferior articular arteries of the popliteal and the recurrent branches of the anterior and posterior tibial. The lower extremity receives twigs from the posterior and anterior tibial, the peroneal, and the medial malleolar arteries.
Ossification. — The tibia is ossified from one principal centre for the shaft, which appears in the eighth week of intra-uterine life, and two epiphyses, the centres for which appear in the cartilaginous head of the bone toward the end of the ninth month, and in the lower extremity during the second year. The latter unites with the shaft at eighteen, but the union of the head with the shaft does not take place until the twenty-first year, and it may even be delayed until twenty-five. The upper part of the tubercle of the tibia is ossified from the upper epiphysis, and the lower part from the diaphysis.
The fibula (figs. 224, 225) is situated on the lateral side of the leg and, in proportion to its length is the most slender of all the long bones. It is placed nearly parallel to the tibia with which it is connected above and below. In man it is a rudimentary bone and bears none of the weight of the trunk, but is retained on account of the muscles to which it gives origin and its participation in the formation of the ankle-joint. Like other long bones, it is divisible into a shaft and two extremities.
biceps tendon and the fibular (long external) collateral ligament of the knee-joint, medially it presents a round or oval facet [fades articularis capituli], directed upward, forward, and medially, for articulation with the lateral condyle (tuberosity) of the tibia. The margin of the facet gives attachment to the articular capsule of the superior tibio-fibular articulation. Posteriorly, the head rises into a pointed apex (styloid process), which affords attachment to the short lateral ligament of the knee-joint, and on the lateral side, to part of the biceps tendon.
The posterior aspect of the head gives attachment to the soleus, the lateral aspect, extending also in front of the eminence for the biceps, to the peroneus longus; from the anterior aspect fibres of the extensor digiiorum longus arise, whilst the medial side lies adjacent to tlie tibia.
The shaft [corpus fibulse], in its upper three-fourths, is quadrangular, possessing four borders and four surfaces, whereas its lower fourth is flattened from side to side, so as to be somewhat triangular. The borders and surfaces vary exceedingly so that their description is difficult. The anterior crest (or antero-lateral border) commences in front of the head and terminates below by dividing to enclose a subcutaneous surface, triangular in shape, immediately above the
fibular ligament
lateral malleolus. It gives attachment to a septum separating the extensor muscles in front from the peronei muscles on the lateral aspect. The interosseous crest (or antero-medial border), so named from giving attachment to the interosseous membrane, also commences in front of the head, close to the anterior crest, and terminates below by dividing to enclose a rough triangular area immediately above the facet for the talus {astragalus) ; this area gives attachment to the inferior interosseous ligament, and may present at its lower end a narrow facet for articulation with the tibia. The medial crest (or postero-medial border), sometimes described as the oblique line of the fibula, commences at the medial side of the head and terminates below by joining the interosseous crest, in the lower fourth of the shaft. It gives attachment to an aponeurosis separating the tibialis posterior from the soleus and flexor hallucis longus. The lateral crest (or posterolateral border) runs from the back of the head to the medial border of the peroneal groove on the back of the lower extremity; it gives attachment to the fascia separating the peronei from the flexor muscles.
The anterior or extensor surface is the interval between the interosseous and anterior crests. In the upper third it is extremely narrow, but broadens out below, where it is slightly grooved longitudinally. It affords origin to three muscles : laterally, in the upper two-thirds, to the extensor digitorum longus, and, in the lower third, to the peroneals tertius; medially, in the middle third, also to the extensor hallucis longus. The medial surface, situated between the interosseous and medial crests, is narrow above and below, and broadest in the middle. It is grooved and sometimes crossed obliquely by a prominent ridge, the secondary oblique line of the fibula; the surface gives origin to the tibialis posterior, and the ridge to a tendinous septum in the substance of the muscle. The posterior surface
THE TARSUS 191
is the interval between the medial and lateral crests, and is somewhat twisted so as to look backward above and medially below. It serves, in its upper third, for the origin of the soleus, and in its lower two-thirds for the flexor hallucis longus. Near the middle of the surface is the medullary foramen, directed downward toward the ankle. The lateral surface, situated between the anterior and lateral crests, is also somewhat twisted, looking laterally above and backward below, where it is continuous with the groove on the back of the lateral malleolus. The surface is often deeply grooved and is occupied by the peroneus longus in the upper two-thirds and by the peroneus brevis in the lower two-thirds.
The lateral malleolus or lower extremity is pyramidal in form, somewhat flattened from side to side, and joined by its base to the shaft. It is longer, more prominent, and descends lower than the medial malleolus. Its lateral surface is convex, subcutaneous, and continuous with the triangular subcutaneous surface on the shaft, immediately above. The medial surface is divided into an anterior and upper area [facies articularis malleoli], triangular in outline and convex from above downward for articulation with the lateral side of the talus (astragalus), and a lower and posterior excavated area, the digital fossa, in which are attached the transverse iriferior tibio-fibular ligament and the posterior talo-fibular (posterior fasciculus of the external lateral) ligament of the ankle. The anterior border is rough and gives attachment to the anterior talo-fibular (anterior fasciculus of the external lateral) ligament of the ankle, and the anterior inferior tibio-fibular ligament. The posterior border is grooved for the peronei tendons, and near its upper part gives attachment to the posterior inferior tibio-fibular ligament. The apex or summit of the process affords attachment to the calcaneo-fibular (middle fasciculus of the external lateral) ligament of the ankle.
Blood-supply. — The shaft of the fibula receives its nutrient artery from the peroneal branch of the posterior tibial. The head is nourished by branches from the inferior lateral articular branch of the popliteal artery, and the lateral malleolus is supplied mainly by the peroneal, and its perforating and malleolar branches.
Ossification. — The shaft of the fibula commences to ossify in the eighth week of intrauterine life. A nucleus appears for the lower extremity in the second year, and one in the upper extremity during the fourth or fifth year. The lower extremity fuses with the shaft about twenty, but the upper extremity remains separate until the twenty-second year or even later.
It is interesting, in connection with the times of appearance of the two epiphyses of the fibula, to note that the ossification of the lower epiphysis is contrary to the general rule — viz., that the epiphysis toward which the nutrient artery is directed is the last to undergo ossification. This is perhaps explained by the rudimentary nature of the upper extremit}'. In birds the head of the bone is large and enters into the formation of the knee-joint; and in human embryos, during the second month, the fibula is quite close up to the femur.
The human fibula is characterised by the length of its malleolus, for in no other vertebrate does this process descend so far below the level of the tibial malleolus. On the other hand, in the majority of mammals the tibial descends to a lower level than the fibular malleolus. In the human embryo of the third month, the lateral is equal in length to the medial malleolus. At the fifth month the lateral malleolus exceeds the medial by 1.5 mm.; at birth, the lateral malleolus is still longer; and by the second year it assumes its adult proportion.
The tarsal bones [ossa tarsi] (figs. 228, 229) are grouped in two rows: — a proximal row, consisting of the talus and calcaneus, and a distal row, consisting of four bones which, enumerated from tibial side, are the first, second, and third cuneiform bones and the cuboid. Interposed between the two I'ows on the tibial side of the foot is a single bone, the navicular ; on the fibular side the proximal and distal rows come into contact.
Compared with the carpus, the tarsal bones present fewer common characters, and greater diversity of size and form, in consequence of the modifications for supporting the weight of the trunk. On each, however, six surfaces can generally be recognised, articular when in contact with neighbouring bones, elsewhere subcutaneous or rough for the attachment of ligaments. As regards ossification, they correspond in the main with that of the bones of the carpus. Each tarsal bone is ossified from a single centre, but the calcaneus has, in addition, an epiphysis for a large part of its posterior extremity, and the talus, an occasional centre for the os trigonum.
The talus (or astragalus) (figs. 230, 231) is, next to the calcaneus, the largest of the bones of the tarsus. Above it supports the tibia, below it rests on the calcaneus, at the sides it articulates with the two malleoli, and in front it is received into the navicular. For descriptive purposes, it may be divided into a head, neck, and body.
Extensor digitorum longus
The body is somewhat quadrilateral in shape. The upper surface presents a broad, smooth surface for the tibia, slightly concave from side to side, convex from before backward, and wider in front than behind. "The diminution in width posteriorly is associated with an obliquity of the lateral margin, which is directed medially as well as backward and downward. The inferior surface is occupied by a transversely disposed oblong facet [taoies articularis calcanea
posterior], deeply concave from side to side, which articulates with a corresponding surface on the calcaneus. Of the malleolar sm-faces, the lateral is almost entirely occupied by a large triangular facet, broad above, where it is continuous with the superior surface, concave from above downward, for articulation with the lateral malleolus; on the medial malleolar surface is a pyriform facet continuous with the superior surface, broad in front and narrow behind, which articulates with the medial malleolus. Below this facet the medial surface is rough for the attachment of the deep fibres of the deltoid (internal lateral) ligament of the ankle. The
Flexor hallucis longus
superior surface and the two malleolar surfaces together constitute the trochlea. The posterior Surface is of small extent and marked by a groove which lodges the tendon of the flexor hallucis longus. Bounding the groove on either side are two tubercles, of which the lateral [processus posterior tali] is usually the more prominent, for attachment of the posterior talo-fibular ligament of the ankle-joint; the medial tubercle gives attachment to the medial talo-calcaneal ligament. Continuous, with the anterior aspect of the body is the neck, a con-
strioted part of the bone supporting the head. Above it is rough, and perforated by numerous vascular foramina. Below, it presents a deep groove [sulcus tali], directed from behind forward and lateralward. When the talus is articulated with the calcaneus, this furrow is converted into a canal [sinus tarsi] in which is lodged the interosseous talo-calcaneal ligament. The head is the rounded anterior end of the bone, and its large articular surface is divisible into three parts: in front, a smooth, oval convex area, directed downward and forward for the navicular bone; below, an elongated facet, convex from front to back, for articulation with the sustentaculum taJi of the calcaneus; and between these, is a small facet which rests on the calcaneo-
joint.
Articulations. — The talus articulates with four bones and two ligaments. Above and medially with the tibia, below with the calcajieus, in front with the navicular, laterally with the fibula. The head articulates with the calcaneo-navicular ligament and the lateral border of the superior surface, at its posterior part, with the transverse ligament of the inferior tibiofibular joint.
Os trigonum
Ossification. — The talus is ossified from one, occasionallj* from two, nuclei. The principal centre for this bone appears in the middle of the cartilaginous talus at the seventh month of intra-uterine life. The additional centre is deposited in the posterior portion of the bone, and forms the lateral posterior tubercle which may remain separate from the rest of the bone and form the os trigonum. At birth, the talus presents some important peculiarities in the disposition of the articular facet on the tibial side of its body, and in the obliquity of its neck. If, in the adult talus, a line be drawn through the middle of the superior trochlear surface parallel with its medial border, and a second line be drawn along the lateral side of the neck of the bone so as to intersect the first, the angle formed by these two lines will express the obliquity of the neck of the bone. This in the adult varies greatly, but the average may be taken as 10°. In the
foetus at birth the angle averages 35°, whilst in a young orang it measures 45°. In the normal adult talus the articular surface on the tibial side is limited to the body of the bone. In the foetal talus it extends for some distane on to the neck, and sometimes reaches almost as far forward as the navicular facet on the head of the bone. This disposition of the medial malleolar facet is a characteristic feature of the talus in the chimpanzee and the orang. It is related to the inverted position of the foot which is found in the human foetus almost up to the period of birth, and is of interest to the surgeon in connection with some varieties of club-foot. (Shattock and Parker.)
The Calcaneus
The calcaneus (or os calcis) (figs. 232, 233) is the largest and strongest bone of the foot. It is of an elongated form, flattened from side to side, and expanded at its posterior extremity, which projects downward and backward to form the heel. It presents six surfaces, superior, inferior lateral, medial, anterior and posterior.
Facet for talus
depression, the floor of which is rough for the attachment of ligaments, especially the talocalcaneal, and the origin of the extensor digitorum hrevis muscle; when the calcaneus and talus are articulated, this portion of the bone forms the floor of a cavity called the sinus tarsi. Medially, the upper surface of the bone presents a well-marked process, the sustentaculum tali, furnished with an elongated concave facet, occasionally divided into two, for articulation with the under aspect of the head of the talus. The posterior part of the upper surface is nonarticular, convex from side to side, and in relation with a mass of fat placed in front of the tendo Aohillis.
The inferior surface is narrow, rough, uneven, and ends posteriorly in two processes: the medial is the larger and broader, the lateral is narrower but prominent. The medial process affords origin to the abductor hallucis, the flexor digitorum brevis, and the abductor digiti quinti; the last muscle also arises from the lateral process and from the ridge of bone between. The rough surface in front of the tubercles gives attachment to the long plantar ligament (calcaneocuboid) and the lateral head of the quadratus plantoe. Near its anterior end this surface forms a rounded eminence, the anterior tubercle, from which (as well as from the shallow groove in front) the plantar (short) calcaneo-cuboid ligament arises. (According to the BNA nomenclature, the medial and lateral processes belong to the tuber calcanei or the posterior extremity of the bone.)
The lateral surface is broad, flat, and slightly convex. It represents near the middle a small eminence for the calcaneo-fibular ligament of the ankle-joint. Below and in front of this is a well-marked tubercle — the trochlear process [processus trochlearis] (or peroneal tubercle), separating two grooves, the upper for the peroneus brevis and the lower for the peroneiis longus.
The medial surface is deeply concave, the hollow being increased by the prominent medial process behind and the overhanging sustentaculum tali in front. The latter forms a prominence of bone projecting horizontally, concave and articular above, grooved below for the tendon of the flexor hallucis longus, and giving attachment to a slip of the tendon of the tibialis posterior, the inferior calcaneo-navicular ligament, and some fibres of the deltoid ligament of the ankle-joint. The hollow below the process receives the plantar vessels and nerves and its lower part gives attachment to the medial head of the quadratus planice.
The posterior surface is oval in shape, rough, and convex. It is divided into three parts: — an upper, smooth and separated by a bursa from the tendo Aohillis; a middle part giving attachment to the tendo Achillis and the plantaris, and a lower part in relation to the skin and fat of the heel. The expanded posterior extremity of the bone is known as the tuber calcanei.
Appears at the tenth, and unites at the sixteenth year
Ossification. — The primary nucleus appears in the sixth month of intra-uterine life. The epiphysis, for its posterior extremity, begins to be ossified in the tenth year and is united to the body of the bone by the sixteenth year. It may extend over the whole of the posterior surface, as shown in fig. 233, or over the lower two-thirds only, leaving a part above in relation to the bursa beneath the tendo Achillis, which is formed from the primary nucleus. The medial and lateral processes are formed by the epiphysis.
The Naviculae
The navicular [os naviculare pedis] (figs. 234, 235) is oval in shape, flattened from before backward, and situated between the talus behind and the three cuneiform bones in front. It is characterised by a large oval, concave, articular
facet on the posterior surface, which receives the head of the talus; a broad, rough, rounded eminence on the medial surface, named the tuberosity of the navicular, the lower part of which projects downward and gives insertion to the tendon of
For cuboid
the tibialis posterior; and an oblong-shaped anterior surface, convex and chvided by two vertical ridges into three facets which articulate with the three cuneiform bones. The superior (dorsal) surface is rough, convex, and slopes downward to
the tuberosity; the inferior (plantar) surface is irregular and rough for the attachment of the inferior cAlcaneo-navicular ligament, and the lateral surface is rough and sometimes presents a small articular surface for the cuboid.
front, and occasionally with the cuboid on its lateral aspect.
Ossification. — The nucleus for the navicular appears in the course of the fourth year. The tuberosity of the navicular, into which the tibialis posterior acquires its main insertion, occasionally develops separately, and sometimes remains distinct from the rest of the bone.
The Cuneiform Bones
Of the three cuneiform bones, the first is the largest, the second is the smallest, and the third intermediate in size. They are wedge-shaped bones placed between the navicular and the first, second and third metatarsal bones. Posteriorly, the ends of the bones lie in the same transverse line, but in front, the first and third project farther forward than the second, and form the sides of a deep recess into which the base of the second metatarsal bone is received.
For first metatarsal
The first cuneiform [os cuneiforme primum] (figs. 236, 237) is distinguished by its large size and by the fact that when articulated, the base of the wedge is directed downward and the apex upward. The posterior surface is concave and pyritorm for articulation with the medial facet on the anterior surface of the navicular. The anterior surface forms a reniform articular facet for the base of the first metatarsal. The medial surface is rough, and presents an oblique groove for the tendon of the tibialis anterior; this groove is limited inferiorly by an oval facet into which a portion of the tendon is inserted. The lateral surface is concave and presents along its superior and posterior borders a reversed L-shaped facet for articulation with the second cuneiform, and, at its anterior extremity, with the second metatarsal. Anteriorly it is rough for ligaments. The inferior surface is rough for the insertion of the peroneus longus, tibialis anterior, and (usually) the tibialis posterior. The superior surface is the narrow part of the wedge and is directed upward.
The second cuneiform [os cuneiforme secundum] (figs. 238, 239) is placed with the broad extremity upward and the narrow end downward, and is readily recognised by its nearly square base. The posterior surface, triangular and concave, articulates with the middle facet on the anterior surface of tlie navicular. The anterior surface, also triangular, but narrower than the posterior surface, articulates with the base of the second metatarsal. The medial surface has a reversed L-shaped facet running along its superior and posterior margins for articulation with the corresponding facet on the first cuneiform, and is rough elsewhere for the
attachment of ligaments. On the lateial surface near its posterior border is a vertical facet, sometimes bilobed, for the third cuneiform, and occasionally a second facet at the anterior inferior angle. The superior surface forms the square-cut base of the wedge and is rough for the attachment of ligaments. The inferior surface is sharp and rough for ligaments and a slip of the tendon of the tibialis posterior.
jional facet for third cuneiform
second cuneiform, the posterior surface presents a triangular facet for the navicular; and the anterior surface a triangular facet, longer and narrower, for the third metatarsal. The medial surface has a large facet extending along the posterior border for the second cuneiform, and along the anterior border a narrow irregular facet for the lateral side of the base of the second metatarsal. Occasionally, a small facet is present near the anterior inferior angle for the second
the second cuneiform
cuneiform. The lateral surface has a large distinctive facet near its posterior superior angle for the cuboid, and at the anterior superior angle there is usually a small facet for the medial side of the base of the fourth metatarsal. The superior surface, oblong in shape, is rough for ligaments, and the inferior, forming a rounded margin, receives a slip of the tibialis posterior and gives origin to a few fibres of the^e:!;or hallucis brevis.
Articulations. — With the navicular behind, third metartarsal in front, cuboid and fourth metatarsal on the lateral side, .second cuneiform and second metatarsal on the me'dial side. Ossification. — A single nucleus appears in the course of the first year.
Its posterior surface is somewhat quadrangular with rounded angles and presents a saddleshaped articular surface for the calcaneus. Its lower and medial angle is somew-hat prolonged backward beneath the sustentaculum tali (calcaneal process of the cuboid), an arrangement to oppose the upward or outward movement of the bone. This process occasionally terminates
in a rounded facet which plays on the head of the talus lateral to the facet for the calcaneo navicular ligament. The anterior surface is smaller and divided by a vertical ridge into two articular facets, a lateral for the base of the fifth, and a medial for the base of the fourth metatarsal. The superior surface is rough, non-articular, and directed obliquely upward. The inferior surface presents a prSminent ridge for the attachment of the long plantar (calcaneocuboid) ligament, in front of which is a deep groove — the peroneal groove — running obliquely forward and medially and lodging the tendon of the peroneiis longus. The ridge terminates laterally in an eminence, the tuberosity of the cuboid, on which there is usually a facet for a sesamoid bone of the tendon contained in the groove. The part of the surface behind the ridge is rough for the attachment of the plantar (short) calcaneo-cuboid ligament, a slip of the tibialis posterior, and a few fibres of the flexor hallucis hrevis.
The medial surface presents, near its middle and upper part, an oval facet for articulation with the third cuneiform bone (fig. 242); behind this, a second facet for the navicular is frequently seen (fig. 243). Generally the two facets are confluent and then form an elliptical surface (fig. 244). The remainder of this surface is rough for the attachment of strong interosseous ligaments.
of birth.
Accessory tarsal elements. — As in the carpus, a number of additional elements may occur in the tarsus. The most frequent of these is the os trigonum, which has already been noticed. Ne.\t in frequency is an additional first cuneiform, resulting from the ossification of the plantar half of that bone independently of the dorsal half, so that the bone is represented by a plantar and a dorsal first cuneiform. Other additional elements may occasionally occur at the upper posterior angle of the sustentaculum tali; at the anterior superior angle of the calcaneus, between that bone and the navicular; in the angle between the first cuneiform and the first and second metatarsals; and in the fibular angle between the fifth metatarsal and the cuboid (os Vesalianum).
The fibular portion of the navicular is sometimes united to the cuboid and quite separate from the rest of the navicular, the cuboid in such eases articulating with the talus. This condition suggests the recognition of the fibular portion of the navicular as a distinct accessory tarsal element, the cuboides secundarium, though it has not yet been observed as an independent bone in the human foot.
The metatarsus [ossa metatarsalia] consists of a series of five somewhat cylindrical bones. Articulated with the tarsus behind, they extend forward, nearly parallel with each other, to their anterior extremities, which articulate with the toes, and are numbered according to their position from great toe to small toe. Like the corresponding bones in the hand, each presents for examination a three-sided shaft, a proximal extremity termed the base, and a distal extremity or head. The shaft tapers gradually from the base to the head, and is slightly curved longitudinally so as to be convex on the dorsal and concave on the plantar aspect.
A typical metatarsal bone. — The shaft [corpus] is compressed laterally and presents for examination three borders and three surfaces. The two borders, distinguished as medial and lateral, are sharp and commence behind, one on each side of the dorsal aspect of the tarsal extremity, and, gradually approaching in the middle of the shaft, separate at the anterior end to terminate in the corresponding
tubercles. The inferior border is thick and rounded and extends from the under aspect of the tarsal extremity to near the anterior end of the bone, where it bifurcates, the two divisions terminating in the articular eminences on the plantar aspect of the head. Of the three surfaces, the dorsal is narrow in the middle and wider at either end. It is directed upward and is in relation -with the extensor tendons. The medial and lateral surfaces, more extensive than the dorsal, corresponding with the interosseous spaces, are separated above, but meet together at the inferior border; they afford origin to the interosseous muscles. The base is wedge-shaped, articulating by its terminal surface with the tarsus, and on each side with the adjacent metatarsal bones. The dorsal and plantar surfaces are rough for the attachment of ligaments. The head presents a semicircular articular surface for the base of the first jjhalanx, and on each side a depression, surmounted by a tubercle, for the attachment of the lateral ligaments of the metatarso-phalangeal joint. The inferior surface of the head is grooved for the passage of the flexor tendons and is bounded by two eminences continuous with the terminal articular surface.
The first metatarsal (fig. 245) is the most modified of all the metatarsal bones, and deviates widely from the general description given above. It is the shortest, the thickest, the strongest, and most massive of the series. The base presents a large reniform, slightly concave facet for the first cuneiform and projects downward into the sole to form the tuberosity, a rough eminence into which the peroneus longus and a slip of the tibialis anterior are inserted. A little
above the tuberosity, on its lateral side, there is occasionally a shallow, but easily recognised facet, for articulation with the base of the second metatarsal. The head is marked on the plantar surface by two deep grooves, separated by a ridge, in which the two sesamoid bones of the flexor hallucis brevis glide. The shaft is markedly prismatic. The dorsal surface is smooth, broad, and convex, directed obliquely upward; the plantar surface is concave longitudinally
and covered by the flexor hallucis longus and brevis, whilst the lateral surface is triangular in outline, almost vertical, and in relation with the first dorsal interosseous and adductor hallucis obliquus. A few fibres of the medial head of the fii'st dorsal interosseous occasionally arise from the hinder part of the surface adjoining the base, or from the border separating the lateral from the dorsal surface. Somewhere near the middle of the shaft, and on its fibular side, is the nutrient foramen, directed toward the head of the bone.
The second metatarsal (fig. 246) is the longest of the series. Its base is prolonged backward to occupy the space between the first and third cuneiform, and accordingly it is marlced by facets for articulation with each of these bones. The tarsal surface is triangular in outline, with the base above and apex below, and articulates with the second cuneiform bone. On the tibial side of the base, near the upper angle, is a small facet for the first cuneiform, and occa-
sionally another for the first metatarsal a little lower down. The fibular side of the base presents an upper and a lower facet, separated by a non-articular depression, and each facet is divided by a vertical ridge into two, thus making four in all. The two posterior facets articulate with the third cuneiform and the two anterior with the third metatarsal. The base gives attachment to a slip of the tibialis posterior and the adductor hallucis obliquus, whilst from the
The third metatarsal (fig. 247), a little shorter than the second, articulates by the triangular surface of its base with the third cuneiform. On the medial side are two small facets, one below the other, for the second metatarsal, and on the lateral side, a single large facet for the fourth metatarsal. The base gives attachment to a slip of the tibialis posterior and the adductor hallucis obliquus, and from the shaft three interosseous muscles take origin. The nutrient foramen is situated on the tibial side of the shaft and is directed toward the base.
The fourth metatarsal (fig. 248), smaller in size than the preceding, is distinguished by the quadrilateral facet on the base, for the cuboid. The medial side presents a large facet •divided by a ridge into an anterior portion for articulation with the third metatarsal and a, posterior portion for the third cuneiform. Occasionally the cuneiform part of the facet is wanting. On the lateral side of the base is a single facet for articulation with the fifth metatarsal.
The fifth metatarsal (fig. 249), is shorter than the fourth, but longer than the first. It is recognised by the large nipple-shaped process, known as the tuberosity, which projects on the lateral side of the base. It constitutes the hindmost part of the bone and gives insertion to the -peroneus brevis on the dorsal aspect, and flexor brevis digili quinli and the occasional ■abduclor ossis metatarsi quinli on the plantar aspect. The fifth metatarsal articulates behind by an obliquely directed triangular facet with the cuboid, and on the medial side with the fourth metatarsal. The plantar aspect of the base is marked by a shallow groove which lodges the tendon of the abductor digili quinli, and the dorsal surface, continuous with the superior surface of the shaft, receives the insertion of the peroneus terlius. The head is small and turned somewhat laterally in consequence of the curvature of the shaft in the same direction. The shaft differs from that of any of the other metatarsals in being compressed from above downward, instead of from side to side, so as to present superior, inferior, and medial surfaces. It gives origin to the lateral head of the fourth dorsal interosseous and the third plantar interosseous muscles. The nutrient foramen is situated on its tibial side and is directed toward the base.
Ossification. — Each metatarsal ossifies from two centres. The primary nucleus for the shaft appears in the eighth week of embryonic life in the middle of the cartilaginous metatarsal. At birth, each extremity is represented by cartilage, and that at the proximal end is ossified by extension from the primary nucleus', except in the case of the first metatarsal. For this, a nucleus appears in the third year.
The distal ends of the four lateral metatarsals are ossified by secondary nuclei which make their appearance about the third year. Very frequently an epiphysis is found at the distal end of the first metatarsal as well as at its base. The shafts and epiphyses consolidate at the twentieth year. The sesamoids belonging to the flexor hallucis brevis begin to ossify about the fifth year.
The phalanges (fig. 250) are the bones of the toes, and number in all fourteen. Except the great toe, each consists of three phalanges, distinguished as first (proximal), second and third (distal) ; in the great toe the second phalanx is absent.
There is thus a similarity as regards number and general arrangement with the phalanges of the fingers. With the exception of the phalanges of the great toe, which are larger than those of the thumb, the bones of the toes are smaller and more rudimentary than the corresponding bones of the fingers. In all the phalanges, the nutrient foramen is directed toward the distal extremity.
on the plantar aspects. The base of each presents a single oval concave facet for the convex head of the corresponding metatarsal, whilst the head forms a pulley-like surface [trochlea phalangis], grooved in the centre and elevated on each side for the second phalanx.
The phalanges of the second row are stunted, insignificant bones. Their shafts, besides being much shorter, are flatter than those of the first row. The bases have two depressions, separated by a vertical ridge, and the heads present trochlear surfaces for the ungual phalanges.
The third, or ungual phalanges are easily recognised. The bases articulate with the second phalanges; the shafts are expanded, forming the ungual tuberosities which support the nails, and their plantar surfaces are rough where they come into relation with the pulp of the digits.
The second phalanges of the remaining toes : Dorsal expansion of the extensor tendons, including extensor digitorum longus, extensor digitorum brevis (except in the case of the fifth toe), and expansions from the interossei and lumbricales.
with the associated muscles.
Ossification, — Like the corresponding bones of the fingers, the phalanges of the toes ossify from a primary and a secondary nucleus. In each, the centre for the shaft appears during the eighth or ninth week of embryonic life. The secondai-y centre forms a scale-like epiphysis for the proximal end between the fourth and eighth years, and union takes place in the eighteenth or nineteenth year — i. e., earlier than the corresponding epiphj'ses in the fingers. The primary centres for the third phalanges appear at the distal extremities of the bones.
In the foot a pah- of sesamoid bones is constant over the metatarso-phalangeal joint of the great toe in the tendons of the flexor hallucis brevis. One sometimes occurs over the interphalangeal joint of the same toe and over the metatarso-phalangeal joints of the second and fifth and rarely of the third and fourth toes.
BONES OF THE FOOT AS A WHOLE
A sesamoid also occurs in the tendon of the peroneus longus, where it glides over the groove in the cuboid; another may be found, especially in later life, in the tendon of the tibialis anterior over the first cuneiform bone, and another in the tendon of the tibialis posterior over the medial surface of the head of the talus. Further a sesamoid, the fabella, sometimes occurs in the lateral head of the gastrocnemius, and another may be found in the tendon of the ilio-psoas over the pubis.
Although the foot is constructed on the same general plan as the hand, there is a marked difference in its architecture to qualify it for the different functions which it is called upon to perform. When in the erect posture, the foot forms a firm basis of support for the rest of the body, and the bones are arranged in an elliptical arch, supported on two pillars, a posterior or calcaneal pillar and an
Fig. 252. — The Secondary Ossific Centres op the Foot. The centre for the epiphysis for calcaneus appears at the tenth year consolidates at the sixteenth year
The centre for the epiphysis for the metatarsal of the hallux appears at the third year; consolidates at the twentieth year
The centres for the base of the terminal phalanges appear at sixth year, and consolidate at the eighteenth year
anterior or metatarsal pillar. It is convenient, however, to regard the anterior part of the arch as consisting of two segments, corresponding to the medial and lateral borders of the foot respectively. The medial segment is made up of the three metatarsal bones, the three cuneiform, the navicular, and talus; the lateral segment is made up of the fourth and fifth metatarsal bones, the cuboid, and the calcaneus, and both segments are supported behind on a common calcaneal pillar. The division corresponds to a difference in function of the two longitudinal arches. Both are intimately concerned in ordinarj- locomotion. In addition, the medial, characterised by its great curvature and remarkable elasticitj^, sustains the more violent concussions in jumping and similar actions, whereas the lateral, less curved, more rigid, and less elastic arch forms, with the pillars in front and behind, a firm basis of support in the upright posture.
provision is accordingly made, by the addition of a strong calcaneo-navicular ligament, for the support of the head of the talus. This ligament is in turn supported by its union with the deltoid ligament of the ankle, and by the tendon of the tibialis posterior which passes beneath it to its insertion.
Besides being arched longitudinally, the foot presents a transverse arch formed by the metatarsal bones in front and the distal row of the tarsus behind. It is produced by the marked elevation of the central portion of the medial longitudinal arch above the ground, whereas the lateral longitudinal arch is much less raised, and at its anterior end becomes almost horizontal. Both the longitudinal and transverse arches serve the double purpose of increasing the strength and elasticity of the foot and of providing a hollow in which the muscles, nerves, and vessels of the sole may lie protected from pressure.
Homology of the Bones of the Limbs
That there is a general correspondence in the plan of construction of the two extremities is apparent to a superficial observer, and this becomes more marked when a detailed examination of the individual bones, their forms and relations, their embryonic and adult peculiarities, is systematically carried out. In each limb there are four segments, the shoulder girdle corresponding to the pelvic girdle, the arm to the thigh, the forearm to the leg, and the hand to the foot. These parts have been variously modified, in adaptation to the different functions of the two limbs, particularly as regards the deviations or changes from what is regarded as their primi-
tive position, and as a knowledge of these changes is essential to a clear understanding of the homologous bones, it will be advantageous to refer briefly to the relations of the limbs in the earliest stages of development.
The limbs first appear as flattened, bud-like outgrowths from the sides of the trunk. Each presents a dorsal or extensor surface, and a ventral or flexor surface, as well as two borders, an anterior, or cephalic, directed toward the head end of the embryo, and a posterior or caudal, du-ected toward the tail end. In reference to the axis of the limb itself, the borders have been called pre-axial and post-axial, respectively. When, somewhat later, the various divisions of the limb make their appearance, it is seen that the gi-eater tuberosity, the lateral epicondyle, the radius, and the thumb he on the pre-axial border of the anterior extremity, and the small trochanter, the medial condyle, the tibia, and the great toe on the pre-axial border of the posterior extremity. Further on the post-axial border of the anterior extremity are seen the lesser tuberosity, the medial epicondyle, the ulna, and little finger, whilst on the corresponding border of the posterior limb are the great trochanter, the lateral condyle, the fibula, and the little toe. The parts now enumerated on the corresponding borders of the two limbs must therefore be regarded as serially homologous (fig. 253).
(1) Each segment of the limb is bent upon the one above it. The humerus and femur remain unchanged. The forearm segment, however, is bent so that the ventral surface looks medially and the dorsal surface laterally. Moreover, the joints between these segments — i. e., elbow and knee — form marked projections. The terminal segments (hand and foot) are bent in the opposite direction to the middle one, so that the primitive position is retained, and the ends of the digits directed laterally. It will be noticed that in this series of changes the relations of the pre-axial and post-axial borders of the limbs remain as before.
(2) This stage consists in a rotation of the whole limb from the proximal end, though in an exactly opposite direction in each case. The anterior extremity is rotated backward so that the humerus lies parallel with the trunk; the elbow is directed toward the caudal end, the pre-axial (radial) border becomes lateral, and the post-axial border medial. The ends of the digits point backward. The posterior extremity undergoes a rotation forward to the same extent, so that the femur is also nearly parallel with the trunk; the knee is directed toward the head end, the pre-axial (tibial) border becomes medial, and the post-axial border lateral. The tibia and fibula are parallel, the ends of the digits are directed forward, the gi-eat toe is on the pre-axial and the Uttle toe on the post-axial border of the Umb, and in this position the posterior extremity remains, the changes being finally completed by the extension of the Hmb at the hip-joint as the body attains its full development.
(3) This stage affects the anterior extremity alone and consists in a rotation of the radius, carrying the hand round the ulna so that the digits are brought round from the back to the front of the limb, and in many animals the maOus is thus placed permanently in the prone position. But in man, in whom the capacity for pronation and supination is highly developed, the hand can assume either position at will. In his case the final change is the extension which takes place at the shoulder-joint with the assumption of the upright posture, the limb dropping loosely at the side of the body, and being endowed with the greatest freedom of movement.
I. The shoulder and pelvic girdles. — Primarily the lateral half of each girdle consists of a curved bar or rod of cartilage placed at right angles to the longitudinal axis of the trunk and divisible into a dorsal segment, and a ventral segment, the point of division corresponding to the place of articulation with the limb-stalk — i. e., the glenoid and acetabular cavities. In the fore-limb the dorsal segment is the scapula, and the ventral segment the coracoid, whilst in the hind-hmb the dorsal segment is the iUum and the ventral segment the ischium and pubis.
The dorsal segments of the two girdles — i. e., scapula and ihum — are accordingly regarded as homologous bones, the chief difference being that whereas the scapula is free from articulation with the vertebral column, the ilium is firmly jointed to the rib elements (lateral mass) of the sacrum. But the correspondence is not quite so clear with regard to the ventral segments. In the primitive condition the coracoid articulates with the side of the sternum, an arrangement which persists throughout hfe in certain animals, such as reptiles and Ornithorhynchus. But in aU the higher mammals it undergoes reduction, withdrawing from the side of the sternum, and eventually forming a more or less rudimentary process attached to the scapula. In the more generahsed form of shoulder girdle the ventral bar is double, consisting of coracoid and precoracoid elements, the latter being situated in front and almost parallel with the coracoid. The pre-coracoid in mammals is largely replaced by the development over it of the clavicle, a dermal or membranous splint-bone which eventually invades the underlying cartilage. Parts, however, remain distinct and form the sternal epiphysis of the clavicle, the inter-articular cartilage between it and the sternum, the supra-sternal bones, and the inconstant inter-articular cartilage in the acromio-clavicular joint.
It has already been noticed that in the hip girdle the ventral segment also consists of two elements, the pubis and ischium. Both take part in the formation of the acetabular cavity, and the pubis meets in the ventral median line the corresponding segment of the opposite side.
It is generally agreed that the coracoid and ischium are homologous structures. The pubic portion of the ventral segment appears to correspond most closely with the pre-coracoid element of reptiles, so that there is no true homologue of the clavicle in the pelvis. If, however, the clavicle corresponds to the reptilian pre-coracoid, as believed by many anatomists, it then becomes the representative of the pubis,
From a consideration of the condition in oranio-cleido-dysostosis, Mr. FitzwiUiams has put forward the following views regarding the homology of the shoulder girdle: — Coracoid bar is represented by (a) medial two-thu'ds of clavicle; (b) coraco-clavicular ligaments; and (c) sub-coracoid centre of coracoid process. The clavicula, a membranous bone, is represented by the lateral third of adult clavicle. The pre-coracoid bar is represented by: — (a) the coracoid process (less the sub-coracoid centre) ; and (b) the costo-coracoid ligament. The epi-coracoid is represented by the meniscus of the sterno-clavicular joint.
Moreover, it is possible to establish a comparison between the individual parts of the ilium and scapula. A reference to fig. 253 shows that both the scapula and ilium may be resolved into three-sided prismatic rods, each of which has thi-ee surfaces and three borders. In the primitive position of the limb one surface — the internal — is turned toward the vertebral column, the remaining surfaces are external, and named -pre-axial and post-axial, corresponding to the borders of the limb. The borders separating the internal from the external surfaces are antero-internal (terminating in the acromion or pubis) and postero-internal (terminating in the coracoid or ischium). The two external surfaces are separated by a ridge, terminating below at the upper margin of the glenoid cavity or acetabulum (glenoid and cotyloid borders).
The primitive arrangement is lost by the marked growth of the borders of the rods leading to the formation of fossae and by the rotation of each rod, the scapula laterally and the ihum medially, in association with the rotation which takes place in the free part of the limb, so that
the inner surface of the one comes to correspond with the outer surface of the other. It results that the primitive vertebral surface of the scapula is now the pre-scapular or supraspinous fossa, and the corresponding surface in the ilium is the sacral, which, on account of its close connection with the vertebral column, undergoes but little change in position. Further, the primitive pre-axial surfaces are the infraspinous fossa and the iliac fossa, which accordingly are to be regarded as homologous, as well as the two post-axial surfaces, the subscapular fossa and the dorsum ilii. The correspondence between the various parts of the scapula and ilium is shown in the appended table (after Flower).
II. Bones of the arm and thigh, forearm, and leg. — It has already been pointed out in describing the deviation of the limbs from the primitive position that the humerus corresponds to the femur, the radius to the tibia, and the ulna to the fibula; also that in consequence of the rotation backward of the fore-limb, and forward of the hind-limb, the lateral side of the humerus corresponds with the medial aide of the femur, the radial border of the forearm to the tibial border of the leg, and the ulnar (border of the forearm) to the fibular border of the leg. The corresponding parts are tabulated below: —
Patella
III. Bones of the hand and foot. — It is obvious that the carpus and tarsus, the metacarpus and metatarsus, and the various digits, commencing at the thumb, in the hand, and at the great toe, in the foot, are serially homologous.
In order to trace the correspondence between the various elements of the carpus and tarsus it is convenient to refer in the first place to the primitive type of hand and foot as found in the water-tortoise and the lizard (fig. 254). In each segment nine elements may be recognised, arranged in a proximal row of three, named respectively radiate or tibiale, intermedium, and ulnare, or flbulare, a distal row of five carpalia, or tarsalia, numbered from one to five, commencing at the pre-axial border, and between the two rows an os cenlrale.
In man the carpus is derived from the typical form in the following manner: The radiale forms the navicular, intermedium the lunate, and the ulnare, the triquetral; carpale I forms the greater multangular, oarpale II the lesser multangular, carpale III the capitate, whilst carpaha IV and V coalesce to form the hamate. The os centrale is present in the human carpus at an early stage, but in the second month it joins the navicular. It is occasionally separate — a normal arrangement in most of the primates.
In the tarsus, the tibiale and intermedium coalesce to form the talus, and the fibulare becomes the calcaneus. It is interesting to note that although in the human subject there are three bones in the first row of the carpus and two in the first row of the tarsus, in carnivores the navicular and lunate are united to form a naviculo-lunate bone — the homologue of the talus. In the human tarsus the intermedium occasionally remains distinct as the os trigonum.
navicular.
In addition to the carpal and tarsal elements enumerated above, brief mention must now be made of the sesamoid bones of the two segments, which are regarded by many anatomists as vestiges of suppressed digits. In the hand are the ulnar and radial sesamoids, the ulnar being represented by the pisiform and the radial probably by the tuberosity of the navicular. (In the mole and other aUied species with fossorial habits, the radial sesamoid is greatly developed to form a sickle-shaped bone which has received the name of os falciforme.)
References. — ^For the development of the skeleton, consult the bibliography in Bardeen's article in Keibel and Mall's ' Human Embryology,' Vol. 1. For further references concerning the adult structure and morphology of the skeleton, the sections on osteology in the larger works on human anatomy by Quain, von Bardeleben, Rauber-Kopsch. Poirier-Charpy, etc., should be consulted. References to the most recent literature may be found in Schwalbe's Jahresbericht, the Index Medicus, and in the various anatomical journals.
THE CONSTITUENTS OF AN ARTICULATION
THE section devoted to the Articulations or Joints deals with the union of the various and dissimilar parts of the human skeleton. The followiing structures enter into the formation of joints. Bones constitute the basis of most joints. The long bones articulate by their ends, the flat by their edges, and the short at various parts on their surfaces. The articular ends are usually expanded, and are composed of cancellous tissue, surrounded by a dense and strong shell of compact tissue.
This shell has no Haversian canals (the vessels of the cancellous tissue turn back and do not perforate it), or large lacunae, and no canaliculi, and is thus well adapted to bear pressure. This "osteoid" layer may represent in part calcified cartilage rather than true bone.
The cartilage which covers the articular ends of the bones is called articular, and is of the hyaline variety. It is firmly implanted on the bone by one surface, while the other is smooth, polished, and free, thus reducing friction to a minimum, while its slight elasticity tends to break jars. It ends abruptly at the edge of the articulation, and is thickest over the areas of greatest pressure.
(i) As inlerarlicular cartilage in diarthrodial joints — viz., in the knee, mandibular, sterno-clavicular, radio-carpal, and occasionally in the acromio-clavicular joint. It is interposed between the ends of the bones, partially or completely dividing the synovial cavity into two. It serves to adjust dissimilar bony surfaces, adding to the security of, while it increases the extent of motion at, the joint; it also acts as a buffer to break shocks.
(ii) As circumferential or marginal iibro-cartilages, which serve to deepen the sockets for the reception of the heads of bones — e. g., the glenoid ligaments of the shoulder and hip. Another form of marginal plate is seen in the accessory volar ligaments of the fingers and toes, which deepen the articulations of the phalanges and add to their security.
(iii) As connecting fibro-cartilage. The more pliant and elastic is the more cellular form, and is found in the intervertebral discs; while the less yielding and more fibrous form is seen in the sacro-iliac and pubic articulations, where there is little or no movement.
The ligaments which bind the bones together are strong bands of white fibrous tissue, forming a more or less perfect capsule [capsula articularis], round the articulation. They are pliant but inextensile, varying in shape, strength, and thickness according to the kind of articulation into which they enter. They are closely connected with the periosteum of the bones they unite. In some cases — as the ligamenta flava which unite parts not in contact — they are formed of j'ellow elastic tissue.
The synovial membrane [stratum synoviale] lines the interior of the fibrous ligaments, thus excluding them, as well as the cushions or pads of fatty tissue situate within and the tendons which perforate the fibrous capsule, from the articular cavity. It is a thin, delicate membrane, frequently forming folds and fringes which project into the cavity of the joint; or, as in the knee, stretches across the cavity, forming a so-called synovial ligament. In these folds are often found pads of fatty tissue, which fill up interstices, and form soft cushions between the contiguous bones. The amount of fat that is normally present within a joint varies greatly. It is an old observation that although there is always fat in the hip-
212 THE ARTICULATIONS
and knee-joints, there is usually none within the shoulder-joint. Sometimes these fringes become villous and pedunculated, and cause pain on movement of the joints. They contain fibro-fatty tissue, with an isolated cartilage cell or two. The synovial membrane is well supplied with blood, especially near the margins of the articular cartilages and in the fringes. It secretes a thick, glairy fluid like white of egg, called synovia, which lubricates the joint. Another variety of synovial membrane is seen in the bursas, which are interposed between various moving surfaces. In some instances bursas in the neighbourhood of a joint may communicate with the synovial cavity of that joint.
CLASSIFICATION OF ARTICULATIONS
Joints may be classified: — (a) From an anatomical point of view, with regard to the substances and the arrangement of the substances by which the constituent parts are united. (6) From a physiological standpoint, with regard to the greater or smaller mobility at the seat of union, (c) From a physical standpoint, either the shapes of the portions in contact being mainly considered or the axes round which movement can occur. Or again (d) a combination of the preceding methods may be adopted, and this is the plan most generally followed. None of the classifications hitherto used is quite satisfactory, but perhaps, on the whole, that suggested by Prof. Alex. Macalister is the least open to objection, and therefore with slight modification it is utilised here.
tween the bones is cartilage.
3. Diarthroses. The constituent parts of joints of this class are (a) two or more bones each covered by articular hyaline cartilage ; (6) a fibrous capsule uniting the bones, and (c) a synovial membrane which lines the fibrous capsule and covers any part of bone enclosed in the capsule and not covered with articular cartilage. An interarticular plate of cartilage may or may not be present.
fangs of the teeth.
(6) Syndesmoses. Movable joints in which the fibrous tissue between bones or cartilages is sufficiently lax to allow movement between the connected parts, e. g., thyreo-hyoid membrane. Interosseous membranes of forearm and leg.
(2) False synchondroses. The plate of cartilage intervening between and connecting the bones is fibro-cartilage and is not part of the cartilage in which the bones were ossified, but is developed separately, e. g., intervertebral joint and pubic symphysis. The articular end of each bone may be covered with hyaUne cartilage and there may be a more or less well-marked cavity in the intervening plate of fibro-cartilage.
intercarpal and acromio-clavicular joints. (6) Ephippial. Saddle-shaped surfaces placed at right angles to each other, admitting free movement in all directions, e. g., metacarpo-phalangeal joint of thumb.
concavity, e. g., wrist and metacarpo-phalangeal joints, (c) Ginglymi. One surface consists of two conjoined condyles or of a segment of a cone or cylinder, and the opposite surface has a reciprocal contour. In these joints movement is only permitted round one axis, which may be transverse; e. g., elbow, ankle; or it may be vertical, in which case the joint is trochoid; e. g., odontoid process of axis with atlas, radius with ulna. Such a classification should be considered as being purely academic and the student must always remember that it is not enough to discuss a joint by assigning it to a particular class in any scheme; for he must be familiar with the actual conditions present in every joint. No classification, however perfect, must be taken as final, and each joint should be studied as a separate thing altogether apart from any general systematic arrangement.
DEVELOPMENT AND MORPHOLOGY OF JOINTS
The arrangement of the various parts which constitute an articulation is best appreciated by a study of the development of the various types of joints. In this way it is easy to recognise a primitive condition typical of each class; but it must be remembered that various modifications take place during growth, that these modifications vary in the individual joints, and produce adult departures from the primitive arrangement which are peculiar to each joint and which must be studied separately.
tWith cartOage bones the articulation may be either a syndesmosis, a synchondrosis, or a diarthrosis. The embryonic tissue in which the cartilage is to develop is at first continuous; centres of chondrification, corresponding in number to the bony elements which are destined to be formed, appearing in it. As the chondrifications approach each other a small portion of the primary embryonic tissue persists between them (fig. 255), and it is the subsequent fate of this intermediate tissue that determines the nature of the articulation.
(1) When the ossification of the cartilage occurs to form the articulating bones, the intermediate tissue may undergo transformation into cartilage (fig. 255), a synchondrosis being thus produced. (2) Or the intermediate tissue may be converted into fibrous connective-tissue
(fig. 255), the result being a syndesmosis. (3) Or, finally, the central portion of the intermediate tissue may degenerate, so that an articular cavity is produced, the peripheral portions being converted into connective tissue, forming a sleeve-like capsule surrounding the cavity, continuous at either extremity with the periosteum of the articulating bones (fig. 255). This is the articular capsule, and the connective-tissue cells arranging themselves in a layer upon its inner surface give rise to a synovial membrane. As the result of these processes a diarthrosis is produced, and from its mode of formation it is clear that the cavity of such an articulation is completely closed.
In a typical diarthrosis there is therefore a ligamentous capsule which entirely encloses the joint cavity, which is continuous with the periosteum of the bones entering into the articulation but which is not attached to nor reflected onto the cartilaginous ends of the bones which constitute the articulating surfaces. Such a capsule constitutes the primitive bond between the articulating bones and furnishes a complete lubricating bag in which these smooth cartilaginous ends gKde over one another. This primitive capsule, however, becomes modified in most adult joints, (1) by unequal development of various parts of the capsule; and (2) by the more or less complete incorporation of other structures which are developmentaUy separate from the capsule. Under the first heading come specially thickened bands which may be so distinctly marked off from the rest of the capsule as to be named as separate hgaments (e. g., the temporo-mandibular ligament of the mandibular joint). Again certain thickened bands of capsule may, with alteration of joint contour, take up anatomical positions which are apparently separated from the rest of the capsule; advanced examples of this process are, in all probability, seen in the ligamentum teres of the hip-joint and the crucial ligaments of the knee. Under the second heading comes a series of ligaments derived from a gi'eat variety of soirrces; the most common origin being from the divorced or rearranged tendons of the muscles around the joint.
Muscles arising from, or inserted into, bones in the immediate vicinity of a joint tend to become metamorphosed into tendon near their attachments, and a comprehensive study of myology in low vertebrate forms indicates that there is associated with this tissue-change a tendency for the muscle to alter its point of attachment; hence a muscle originally inserted below a joint may eventually come to have its insertion above the joint. In the same way, a muscle arising above a joint may, as a result of altered environment, shift its origin to some point below the joint. To this change of position the term migration of muscles has been applied. In many instances a portion of the muscle equivalent to the distance between the original and the acquired attachment persists as a fibrous band and fulfils the function of a Ugament. This is well seen in the knee-joint, where the tibial collateral ligament is derived from the adductor magnus, this muscle having shifted its insertion from the tibia to the femur. In the same way the fibular collateral ligament represents the tendon of the peroneus longus, which has migrated from the femur to the head of the fibula.
Among other ligaments derived in a similar way from muscles may be mentioned the sacratuberous ligament. This was originally the tendon of origin of the biceps femoris. (H. Morris, Med. Times and Gazette, 1877, p. 361.) The sacro-spinous is derived from the fibrous retrogression of portions of the coccygeus. The sacro-coccygeal ligaments represent the muscles which lift, depress, and wag the tail in those mammals furnished with such an appendage; indeed, these ligaments are occasionally replaced by muscle-tissue.
The coraco-humeral ligament is derived from the original tendon of insertion of the pectorahs minor, and not unfrequently the muscle is inserted into the lesser tuberosity of the humerus, the ligament being then replaced by the tendon of the muscle. The coraco-clavicular, rhomboid, and gleno-humeral ligaments are probably derived from modifications of the subclavius muscle.
Other anatomical structures besides muscles may, when degenerated or functionally altered, form the basis of ligaments in connection with joints. The spheno-mandibular ligament is the fibrous remnant of the cartilaginous mandibular bar.
The pulpy substance in the centre of each interoertebral disc is derived from the notochord; the apical ligament passing from the tip of the dens to the anterior margin of the foramen magnum is a remnant of the sheath of the notochord, and indicates its position as it passed from the vertebral column into the base of the cranium. The transverse ligament of the atlas (as pointed out by Professor Cleland) is a persistent and functional form of the posterior conjugal ligament uniting the rib-heads in seals and many other mammals, whilst the interosseous ligament of the head of a rib in man is the feeble representative of this structure in the thoracic region of the spine. The ligamentum conjugate costarum was described by Mayer in 1834 (Mtiller's Archiv fiir Anatomie). According to Luschka's account of this ligament it would seem as though the posterior superior fibres of the capsule of the costo-central joint represented it in man, rather than the interosseous ligament.
The gliding motion is the simplest, and is common to aU diarthrodial joints; it consists of a simple sliding of the apposed surfaces of the bones upon one another, without angular or rotatory motion. It is the only kind of motion permitted in the carpal and tarsal joints, and in those between the articular processes of the vertebne.
The angular motion is more elaborate, and increases or diminishes the angle between difi'erent parts. There are four varieties, viz., flexion and extension, which bend or straighten the various joints, and take place in a forward and backward direction (in a perfect hinge-joint this is the only motion permitted) ; and adduction and abduction, which, except in the case of the fingers.and toes, signifies an approach to, or deviation from, the median plane of the body. In the
the middle finger, while in the foot it is through the second toe.
Rotation is the revolution of a bone about its own axis without much change of position. It is only seen in enarthrodial and trochoidal joints. The knee also permits of slight rotation in certain positions, which is a distinctive feature of this articulation.
Circumduction is the movement compounded of the four angular movements in quick succession, by which the moving bone describes a cone, the proximal end of the bone forming the apex, while the distal end describes the base of the cone. It is seen in the hip and shoulder, as well as in the carpo-metacarpal joint of the thumb, which thus approximates to the ball-andsocket joint.
In some situations where a variety of motion is required, strength, security, and celerity are obtained by the combination of two or more joints, each allowing a different class of action, as in the case of the wrist, the ankle, and the head with the spine. Many of the long muscles, which pass over two or more joints, act on all, so tending to co-ordinate their movements and enabhng them to be produced with the least expenditure of power. Muscles also act as elastic ligaments to the joints; and when acting as such, are diiJusers and combiners, not producers of movement; the short muscles producing movement, the long diffusing it, and thus allowing the short muscles to act on more than one joint.
Muscles are so disposed at their attachments near the joints as never to strain the Ugaments by tending to pull the bones apart, but, on the contrary, they add to the security of the joint by bracing the bones firmly together during their action.
The movable articulations of the skull comprise (1) the mandibular; and (2) those between the skull and the vertebral column, namely (a) between the occiput and atlas ; (6) between the atlas and epistropheus (axis) ; and (c) the ligaments which connect the occiput and epistropheus.
The union of the atlas and epistropheus is described in this section because, (1) there is often a direct communication between the synovial cavity of the transverse epistrophic and the occipito-atlantal joints; (2) the rotatory movements of the head take place around the dens (odontoid process) ; and (3) important ligaments from the dens pass over the atlas to the occiput.
The parts entering into the formation of this joint (figs. 256, 257) are: — the anterior portion of the mandibular fossa and glenoid ridge (eminentia articularis) of the temporal bone above, and the condyle of the lower jaw below. Both are covered with articular cartilage, which extends over the front of the glenoid ridge to facilitate the play of the interarticular cartilage. The ligaments which unite the bones are:
1. The anterior portion consists of a few stray fibres connected with the anterior margin of the articular disc, and attached below to the anterior edge of the condyle, and above to the front of the articular eminence. Some fibres of insertion of the external pterygoid pass between them to be inserted into the margin of the articular disc.
fissure, and is inserted into the back of the jaw just below its neck.
3. The lateral portion or temporo-mandibular (external lateral) ligament (fig. 256) is the strongest part of the capsule. It is broader above, where it is attached to the lower edge of the zygoma in nearly its whole length, as well as to the tubercle at thu point where the two roots of the zygoma meet. It is inoUned downward and backward, to be inserted into the condyle and neck of the mandible laterally. Its fibres diminish in obliquity and strength from before backward, those coming from the tubercle being short and nearly vertical.
4. The medial portion (or short internal lateral ligament) (fig. 257) consists of well-defined fibres, having a broad attachment, above to the lateral side of the spine of the sphenoid and medial edge of the mandibular fossa; and below, a narrow insertion to the medial side of the neck
which is medial to it.
The articular disc (fig. 258) is an oval plate of fibro-cartilage interposed between and adapted to the two articular surfaces. It is thinner at the centre than at the circumference, and is thicker behind, where it covers the thin bone at the bottom of the mandibular fossa which separates it from the dura mater, than in front, where it covers the articular eminence.
Its inferior surface is concave and fits on to the condyle of the lower jaw; while its superior surface is concavo-convex from before backward, and is in contact with the articular surface of the temporal bone. It divides the joint into two separate synovial cavities, but is occasionally perforated in the centre, and thus allows them to communicate. It is connected with the articular capsule at its circumference, and has some fibres of the exiernallpterygoid muscle inserted into its anterior margin.
There are usually two synovial membranes (fig. 258), the superior being the larger and looser, passing down from the margin of the articular surface above, to the upper surface of the articular disc below; the lower and smaller one passes
into the lingula of the lower jaw.
It covers the upper end of the mylo-hyoid groove, and is here pierced by the mylo-hyoid nerve. Its origin is a little medial to, and immediately behind, the origin of the medial portion of the capsule. It is separated from the joint and ramus of the jaw by the external ■pterygoid muscle, the internal maxillary artery and vein, the inferior alveolar {dental) nerve and artery, the auriculo-temporal nerve, and the middle meningeal artery. It is really the fibrous remnant of a part of the mandibular (Meckelian) bar.
The stylo -mandibular ligament (stylo-maxillary) (figs. 256 and 257) is a process of the deep cervical fascia extending from near the tip of the styloid process to the angle and posterior border of the ramus of the jaw, between the masseter and internal ■pterygoid muscles. It separates the parotid from the submaxillary gland, and gives origin to some fibres of the st^ylo-glossus muscle.
Sacs and the Articular Disc.
Articular disc -l^j^ftr •rr _^ r Section through condyle^ — -> — i-4Posterior portion of -ji/lTiN u capsule \»4T^^
Movements. — The chief movement of this joint is of (i) a ginglymoid or hinge character, accompanied by a slight gliding action, as in opening or shutting the mouth. In the opening movement the condyle turns like a hinge on the articular disc, while at the same time the articular disc, together with the condyle, glides forward so as to rise upon the eminentia articularis, reaching as far as the anterior edge of the eminence, which is coated with articular cartilage to receive it; but the condyle never reaches quite so far as the summit of the eminence. Should the condyle, however, by excessive movement (as in a convulsive yawn), glide over the summit, it slips into the zygomatic fossa, the mandible is dislocated, and the posterior portion of the capsule is torn. In the shutting movement the condyle revolves back again, and the articular disc glides back, carrying the condyle with it. This combination of the hinge and gUding motions gives a tearing as well as a cutting action to the incisor teeth, without any extra muscular exertion.
There is (ii) a horizontal gliding action in an antero-posterior direction, by which the lower teeth are thrust forward and drawn back again: this takes place almost entirely in the upper compartment, because of the closer connection of the articular disc with the condyle than with the squamosal bone, and also because of the insertion of the external pterygoid into both bone and cartilage. In these two sets of movements the joints of both sides are simultaneously and similarly engaged.
the vertical axis of its neck in the lower compartment, while the cartilage glides obUquely forward and inward on one side, and backward and inward on the other, upon the articular surface of the squamosal bones, each side acting alternately. If the symphysis be simply moved from the centre to one side and back again, and not from side to side as in grinding, the condyle of that side moves round the vertical axis of its neck, and the opposite condyle and cartilage ghde forward and inward upon the mandibular fossa. But in the ordinary grinding movement, one condyle advances and the other recedes, and then the first recedes while the other advances, slight rotation taking place in each joint meanwhile.
Relations. — The chief relations are: Behind, and overlapping the lateral side, the parotid gland. Laterally, the superficial temporal artery. Medially, the internal maxillary artery and auriculo-temporal nerve. In front, the nerve to the masseter muscle.
This articulation [articulatio atlanto-occipitalis] consists of a pair of joints symmetrically situated on either side of the middle line. The parts entering into their formation are the cup-shaped superior articular processes of the atlas and the condyles of the occipital bone. They are united by the following ligaments : —
The anterior atlanto-occipital ligament [membrana atlanto-occipitalis anterior] (fig. 259) is less than an inch (about 2 cm.) wide, and is composed of densely woven fibres, most of which radiate slightly lateralward as they ascend from the front surface and upper margin of the anterior arch of the atlas to the anterior border of the foramen magnum; it is continuous at the sides with the articular capsules, the fibres of which overlap its edges, and take an opposite direction medially and upward.
The central fibres ascend vertically from the anterior tubercle of the atlas to the pharyngeal tubercle on the occipital bone; they are thicker than the lateral fibres, and are continuous below with the superficial part of the anterior atlanto-epistrophic ligarnent, and through it with the anterior longitudinal ligament of the vertebral column. It is in relation, in front, with the recti capitis anteriores; and behind, with the apical dental or suspensory ligament.
The posterior atlanto-occipital ligament (fig. 260) is broader, more membranous, and not so strong as the anterior. It extends from the posterior surface and upper border of the posterior arch of the atlas to the posterior margin of the foramen magnum from condyle to condyle; being incomplete on either side for the passage of the vertebral artery into, and suboccipital nerve out of, the canal. It is somewhat thickened in the middle line by fibres, which pass from the posterior tubercle of the atlas to the lower end of the occipital crest.
It is not tightly stretched between the bones, nor does it limit their movements; it corresponds with the position of the ligamenta flava, but has no elastic tissue in its composition. It is in relation in front with the dura mater, which is firmly attached to it; and behind with the recti capitis posteriores minores, and enters into the floor of the suboccipital triangle. Its lateral margins, which do not reach the occipital bone but terminate on the posterior end of the superior articular processes of the atlas, form the so-called oblique ligaments of the atlas. The lateral margins of these ligaments are free and they form the posterior boundaries of the apertures through which the vertebral arteries enter and the suboccipital nerves leave the vertebral canal.
The atlanto-occipital articular capsules (figs. 259 and 260) are very distinct and strongly marked, except on the medial side, where they are thin and formed only of short membranous fibres. They are lax, and do not add much to the security of the joint.
ARTICULATION OF ATLAS WITH OCCIPUT
In front, the capsule descends upon the atlas, to be attached, some distance below the articular margin, to the front surface of the lateral mass and to the base of the transverse process ; these fibres take an obUque course upward and medialward, overlapping the anterior atlan tooccipital. At the sides and behind, the capsule is attached above to the margins of the occipital condyles; below, it skirts the medial edge of the foramen for the vertebral artery, and behind is attached to the prominent tubercle overhanging the groove for that vessel; these latter fibres are strengthened by a band running obliqviely upward and medialward to the posterior margin of the foramen magnum.
The anterior oblique or lateral occipito-atlantal ligament is an accessory band which strengthens the capsule laterally (fig. 259). It is an oblique, thick band of fibres, sometimes quite separate and distinct from the rest, passing upward and medialward from the upper surface of the transverse process beyond the costo-transverse foramen to the jugular process of the occipital bone.
Movements. — By the symmetrical and bilateral arrangement of these joints, security and strength are gained at the expense of a very small amount of actual articular surface; the basis of support and the area of action being equal to the width between the most distant borders of the joint.
in extension, the chin is elevated and the forehead recedes.
There is also a slight amount of gliding movement, either directly lateral, the lateral edge of one condyle sinking a little within the lateral edge of the socket of the atlas, and that of the opposite condyle projecting to a corresponding degree. The head is thus tilted to one side, and it is even possible that the weight of the skull may be borne almost entuely on one joint, the articular surfaces of the other being thrown out of contact.
in advance of the elevated side. In this motion, which takes place on the antero-posterior axis, one condyle advances slightly and approaches the middle line, while the other recedes. This is of the nature of rotation, though there is no true rotation round a vertical axis possible between the occiput and atlas.
These lateral movements are checked by the alar ligaments and the lateral part of the capsules; extension is checked by the anterior atlanto-oocipital and anterior oblique ligaments, and flexion by the posterior part of the capsule and the tectorial membrane.
Muscles acting upon the occipito-atlantal joint. — Flexion whereby the chin is approximated toward the sternum is produced by the weight of the anterior part of the head and by all muscles which are attached to the hyoid bone or to the bones of the skuU in front of a transverse axis between the two condyles. These muscles take their fixed point below either from the vertebral columir, the sternum, or the bones of the shoulder girdle. Before those connected with the mandible can act that bone must be fixed by the muscles of mastication which, therefore, also take part in the movements. It must be noted that the sterno-mastoid muscles are powerful flexors, although a part of their insertion is behind the transverse axis between the two condyles.
Extension is due to the action of muscles or portions of muscles inserted into the skull behind the transverse axis above mentioned, and connected below either with the vertebral column, shoulder girdle, or sternum.
The bones that enter into the formation of the lateral joints are the inferior articular processes of the atlas and the superior of the epistropheus (axis); the central joint is formed by the dens (odontoid process) articulating in front with the atlas, and behind with the transverse ligament.
The anterior atlanto-epistrophic ligament (figs. 259 and 260) is a narrow but strong membrane filling up the interval between the lateral joints. It is attached above to the front surface and lower border of the anterior arch of the atlas, and below to the transverse ridge on the front of the body of the epistropheus. Its fibres are vertical, and are thickened in the median line by a dense band which is a continuation upward of the anterior longitudinal ligament of the vertebral column.
This band is fixed above to the anterior tubercle of the atlas, where it becomes continuous with the central part of the anterior atlanto-oocipital ligament (fig. 259) ; it is sometimes separated by an interval from the deeper ligament, and is often described as the superficial atlantoepistrophic ligament. It is in relation with the longus colli muscle.
The posterior atlanto-epistrophic ligament (fig. 260) is a deeper, but thinner and looser membrane than the anterior. It extends from the posterior root of the transverse process of one side to that of the other, projecting laterally beyond the posterior part of the capsules which are connected with it. It is attached above to the posterior surface and lower edge of the posterior arch of the atlas, and below to the superior edge of the laminae of the epistropheus on their dorsal aspect.
It is denser and stronger in the median line, and has a layer of elastic tissue on its anterior surface like the ligamenta flava, to which it corresponds in position. It is connected in front with the dura mater; behind, it is in relation with the inferior oblique muscles, and is perforated at each side by the second cervical nerve.
1. The Lateral Atlanto-epistrophic Joints are provided with short, ligamentous fibres, forming ari:icular capsules (fig. 259), which completely surround the lateral articular facets. Lateral to the canal they are attached some little distance from the articular margins, extending along the roots of the
tectorial membrane
transverse processes of the epistropheus nearly to the tips, but between the roots they skirt the medial edge of the costo-transverse foramina. They are strengthened in front and behind by the atlanto-epistrophic hgaments.
Medially each capsule is thinner, and attached close to the articular mai'gins, being strengthened behind by a strong band of slightly oblique fibres passing upward along the lateral edge of the tectorial membrane from the body of the epistropheus to the lateral mass of the atlas behind the transverse ligament; some of these fibres pass on, thickening and blending with the atlantooocipital capsule, to be inserted into the margin of the foramen magnum. This band is sometimes called the accessory band (fig. 263).
the dens and the transverse hgament.
The transverse ligament (figs. 260, 261, and 263) is one of the most important structures in the body, for on its integrity and that of the alar ligaments our lives largely depend. It is a thick and very strong band, as dense and closely woven as fibro-cartilage, about a quarter of an inch (6 mm.) deep at the sides, and somewhat more in the middle line. Attached at each end to a tubercle on the inner side of the lateral mass of the atlas, it crosses the ring of this bone in a curved manner, so as to have the concavity forward; thus dividing the ring into a smaller anterior portion for the dens and a larger posterior part for the spinal cord and its membranes, and the spinal accessory nerves.
It is flattened from before backward, being smooth in front, and covered by synovial membrane to allow it to glide freely over the posterior facet of the dens. Where it is attached to the atlas it is smooth and well rounded off to provide an easy floor of communication between the transverso-dental and occipito-atlantal joints.
To its posterior surface is added, in the middle line, a strong fasciculus of vertical fibres, passing upward from the root of the dens to the basilar border of the foramen magnum on its cranial aspect. Some of these fibres are derived from the transverse ligament. These vertical fibres give the transverse ligament a cruciform appearance; hence the name, the crucial ligament (figs. 260 and 263) applied to the whole.
completely surrounding the apposed articular surfaces of the atlas and dens.
At the dens it blends above with the front of the alar and central occipito-odontoid ligaments, and arises also along the sides of the articular facet as far as the neck of the dens; the fibres are thick, and blend with the capsules of the lateral joint. At the atlas they are attached to the non-articular part of the anterior arch in front of the tubercles for the transverse ligament, blending, above and below the borders of the bone, with the anterior atlanto-occipital and atlanto-epistrophic ligaments, as well as with the medial portion of the articular capsules. It holds the dens to the anterior arch of the atlas after aU the other ligaments have been divided.
The synovial membranes (figs. 260 and 261) are two in number: — one for the joint between the dens and atlas; and another (transverso-dental) for that between the transverse ligament and the dens. This last often communicates with the atlanto-occipital articulations; it is closed in by membranous tissue between the borders of the transverse ligament and the margin of the facet on the dens, and is separated from the front sac by the atlanto-dental articular capsule.
the first and second cervical nerves.
Movements. — The chief and characteristic movement at these joints is the rotation, in a nearly horizontal plane, of the collar formed by the atlas and transverse ligament, round the dens as a pivot, which is extensive enough to allow of an all-round view without twisting the trunk. Partly on account of its ligamentous attachments, and partly on account of the shape of the articular siirfaces, the cranium must be carried with the atlas in these movements. The rotation is checked by the ligaments passing from the dens to the occiput (alar ligarnents), and also by the atlanto-epistrophic. Owing to the fact that the facets of both atlas and epistropheus, which enter into the formation of the lateral atlanto-epistrophic articulations, are convex from before backward, and have the articular cartilage thicker in the centre than at the circumference, the motion is not quite horizontal but slightly curvilinear. In the erect position, with the face looking directly forward, the most convex portions of the articular surfaces are alone in contact, there being a considerable interval between the edges; dm-ing rotation, therefore, the prominent portions of the condyles of the atlas descend upon those of the epistropheus, diminishing the space between the bones, slackening the ligaments, and thus increasing the amount of rotation, without sacrificing the security of the joint in the central position.
The muscles acting upon the atlanto-epistrophic joints. — The muscles capable of producing rotation at the atlanto-epistrophic joints are those which take origin from near the mesial plane either in front or behind and which are attached above either to the atlas or the skull, lateral to the atlanto-epistrophic joints. When the muscles which lie at the back of the joint on one side act they will turn the head to the same side and will be aided by the muscles in front on the opposite side. If the muscles in front and behind on the same side act simultaneously, they will pull down the head to that side and will be aided by muscles which pass more or less vertically from the transverse process of the atlas to points below.
The following ligaments unite bones not in contact, and are to be seen from the interior of the canal after removing the posterior arches of the epistropheus and atlas and posterior ring of the foramen magnum : —
4. The apical dental ligament.
The tectorial membrane (occipito-cervical hgament) (figs. 261, 262, and 263) consists of a very strong band of fibres, connected below to the upper part of the body of the third vertebra and lower part of the body of the epistropheus as far as the root of the dens. It is narrow below, but widens out as it ascends, to be fastened to the basilar groove of the occiput. Laterally, it is connected with the accessory fibres of the atlanto-epistrophic capsule. It is really only the upward prolongation of the deep stratum of the posterior longitudinal ligament, the superficial fibres of which run on to the occipital bone without touching the epistropheus, thus giving rise to two strata. It is in relation in front with the crucial ligament.
Fig. 262. — The Superficial Layer of the Posteeioe Longitudinal Vertebral Ligament HAS BEEN Removed to show its Deep oh Short Fibres. These Deep Fibres FORM the Tectorial Membrane. Viewed from behind.
The alar (or check) ligaments (figs. 260 and 263) are two strong rounded cords, which extend from the sides of the apex of the dens, transversely lateralward to the medial edge of the anterior portion of the occipital condyles.
They are to be seen immediately above the upper border of the transverse ligament, which they cross obliquely owing to its forward curve at its attachments to the atlas. Some of their fibres occasionally run across the middle line from one alar ligament to the other. At the dens they are connected with the atlan to-dental capsule, and at the condyles they strengthen the atlanto-occipital articular capsule.
The apical dental or suspensory ligament (figs. 260 and 263) consists of a slender band of fibres ascending from the summit of the dens to the lower surface of the occipital bone, close to the foramen magnum. It is best seen from the front, after removing the anterior atlanto-occipital ligament, or from behind by drawing aside the crucial ligament.
The apical ligament is tightened by extension and relaxed by flexion or nodding; the alar ligaments not only limit the rotatory movements of the head and atlas upon the epistropheus, but by binding the occiput to the pivot, round which rotation occurs, they steady the head and prevent its undue lateral inclination upon the vertebral column. (See Transverse Ligament, p. 222.)
By experiments, it has been proved that the head, when placed so that the orbits look a little upward, is poised upon the occipital condyles in a line drawn a little in front of their middle; the amount of elevation varies slightly in different cases, but the balance is always to be obtained in the human body — it is one of the characteristics of the human figm'e. It serves to maintain the head erect without undue muscular effort, or a strong ligamentum nuchse and prominent dorsal spines such as are seen in the lower animals. Disturb this balance, and let the muscles cease to act, the head will either drop forward or backward according as the centre of gravity is in front or behind the balance line. The ligaments which pass over the dens to the occiput are not quite tight when the head is erect, and only become so when the head is flexed; if this were not so, no flexion would be allowed; thus, muscular action, and not ligamentous tension, is employed to steady the head in the erect position. It is through the combination of the joints of the atlas and epistrophaus, and occiput and epistropheus (consisting of two paii-s of joints placed symmetrically on either side of the median line, while through the median line there passes a pivot, also with a pair of joints), that the head enjoys such freedom and celerity of action, remarkable strength, and almost absolute security against violence, which could only be obtained by a ball-and socket joint; but the ordinary ball-and-socket joints are too prone to dislocations by even moderate twists to be reliable enough when the life of the individual depends on the perfection of the articulation: hence the importance of this combination of joints.
TO SHOW Ligaments.
(The tectorial membrane (1), though shown as a distinct stratum, is really the deeper part of the posterior longitudmal ligament (2) The upper ends have been reflected upward the lower downward Viewed from behind.)
(a) Those between the bodies and intervertebral discs which form synchondroses and which are amphiarthrodial as regards movement. (6) Those between the articular processes which form arthrodial joints.
The ligaments which unite the various parts may also be divided into two sets, viz. — immediate, or those that bind together parts which are in contact; and intermediate, or those that bind together parts which are not in contact.
Posterior longitudinal.
The intervertebral fibro-cartilages (figs. 260 and 264) are tough, but elastic and compressible discs of composite structure, which serve as the chief bond of union between the vertebrae. They are twenty-three in number, and are interposed between the bodies of all the vertebrae from the epistropheus to the sacrum (figs. 260 and 271). Similar discs are found between the segments of the sacrum and coccyx in the younger stages of life, but they undergo ossification at their surfaces and often throughout their whole extent.
Each disc is composed of two portions — a circumferential laminar, and a central pulpy portion; the former tightly surrounds and braces in the latter, and forms somewhat more than half the disc. The fibrous ring [annulus fibrosus] or laminar portion consists of alternating layers of fibrous tissue and fibro-oartilage; the component fibres of these layers are firmly connected with two vertebriE, those of one passing obliquely down and to the right, those of the next down and to the left, malving an X -shaped arrangement of the alterriate layers. A few of the superficial lamellie project beyond the edges of the bodies, their fibres being connected with the edges of the anterior and lateral surfaces; and some do not completely siu-round the rest, but terminate at the intervertebral foramina, so that on horizontal section the circumferential portion is seen to be thinner posteriorly. The more" central lamellae are incomplete, less firm, and not so distinct as the rest; and as they near the pulp they gradually assume its characters, becoming more fibro-cartilaginous and less fibrous, and have cartilage cells in their structure.
The pulpy nucleus [nucleus pulposus] or central portion is situated somewhat behind the centre of the disc, forming a baU of very elastic and tightly compressed material, which bulges freely when the confining pressure of the laminar portion is removed by either horizontal or vertical section. Thus, it has a constant tendency to spring out of its confinement in the direction of least resistance, and constitutes a pivot round which the bodies of the vertebrae can twist, tilt, or incline. It is yellowish in colour, and is composed of fine white and elastic
The radiate ligament
fibres amidst which are ordinary connective-tissue cells, and pecuhar cells of various sizes which contain one or more nuclei. Together with the most central laminee, it is separated from immediate contact with the bone by a thin plate of articular cartilage. The central pulp of the intervertebral substance is the persistent part of the notochord.
The intervertebral substances vary in shape with the bodies of the vertebrae they unite, and are widest and thickest in the lumbar region. In the cervical and lumbar regions they are thicker in front than behind, and cause, the convexity forward of the cervical, and increase that of the lumbar; the curve in the thoracic region, almost entirely due to the shape of the bodies, is, however, somewhat increased by the discs. Without the discs the column loses a quarter of its length, and assumes a curve with the concavity forward, most marked a little below the mid-thoracic region. Such is the curve of old age, which is due to the shrinking and drying up of the intervertebral substances. The disc between the epistropheus and third cervical is the thinnest of all (fig. 260) ; that between the fifth lumbar and sacrum is the thickest, and is much thicker in front than behind (fig. 271). The intervertebral discs are in relation, in front with the anterior longitudinal ligament; behind, with the posterior longitudinal ligament; laterally, with the short lateral; and in the thoracic region, with the interarticular and radiate ligaments.
In the cervical region lateral diarthrodial joints are placed one on each side of the intervertebral discs. They are of small extent and are confined to the intervals between the prominent lateral lips of the upper surface of the body below and the bevelled lateral edges of the lower surface of the body above. Situated in front of the issuing spinal nerves and between those parts of the bodies formed from the neural arches, they are homologous with the joints between the atlas and epistropheus, and between the atlas and occipital bone.
VERTEBRAL LIGAMENTS
The anterior longitudinal ligament (figs. 259 and 265) commences as a narrow band attached to the inferior surface of the occipital bone in the median line, just in front of the atlanto-occipital Ugament, of which it forms the thickened central portion. Attached firmly to the tubercle of the atlas, it passes down as the central portion of the atlanto-epistrophic ligament, in the mid-line, to the front of the body of the epistropheus. It now begins to widen out as it descends, until it is nearly two inches (5 cm.) wide in the lumbar region. Below, it is fixed to the upper segment of the sacrum, becoming lost in periosteum about the middle of that bone; but is again distinguishable in front of the sacro-coccygeal joint, as the anterior sacro-coccygeal ligament.
Its structure is bright, pearly-white, and gUstening. Its lateral borders are separated from the lateral bands by clefts through which blood-vessels pass; they are frequently indistinct and are best marked in the thoracic region. It is thickest in the thoracic region, and thicker in the lumbar than the cervical. It is firmly connected with the bodies of the vertebra, and is composed of longitudinal fibres, of which the superficial extend over several, while the deeper pass over only two or three vertebrae. It is connected with the tendinous expansion of the prevertebral muscles in the cervical, and the crura of the diaphragm are closely attached to it in the lumbar region.
The posterior longitudinal ligament (figs. 263, 266, 267, and 274) extends from the occipital bone to the coccyx. It is wider above than below, and commences by a broad attachment to the cranial surface of the basi-occipital. In the cervical region it is of nearly uniform width, and extends completely across the bodies of the vertebrae, upon which it rests quite flat. It does, however, extend slightly further laterally on each side opposite the intervertebral discs. In the thoracic and lumbar regions it is distinctly dentated, being broader over the intervertebral substances and the edges of the bones than over the middle of the bodies, where it is a narrow band stretched over the bones without resting on them, the anterior internal vertebral venous plexus being interposed. The narrow median portion consists of longitudinal fibres, some of which are superficial and pass over several vertebrae; and others are deeper, and extend only from one vertebra to the next but one below.
ward over an intervertebral fibro-cartilage, and reach the narrow portion of the ligament on the centre of the vertebra next below; they then diverge to pass over another intervertebral dies to end on the body of the vertebra beyond, near the intervertebral notch. They thus pass over two discs and three vertebrae. Deeper still are other fibres thickening these expansions of the longitudinal hgament, and extending from one bone to the next.
The last well-marked expansion is situated between the first two segments of the sacrum: 'below this, the ligament becomes a deUcate central band with rudimentary expansions, being more pronounced again over the sacro-coccygeal joint, and losing itself in the ligamentous tissue at the back of the coccyx. The dura mater is tightly attached to it at the margin of the foramen magnum and behind the bodies of the upper cervical vertebrae, but is separated from it in the rest of its extent by loose cellular tissue which becomes condensed in the sacral region to form the sacro-dural ligament. The filum terminale becomes blended with it at the lower part of the sacrum and back of the coccyx.
Expanded lateral portion
The lateral (or short) vertebral ligaments (fig. 265) consist of numerous short fibres situated between the anterior and posterior longitudinal ligaments, and passing from one vertebra over the intervertebral disc, to which it is firmly adherent, to the next vertebra below.
The more superficial fibres are more or less vertical, but the deeper decussate and have a crucial arrangement. They are connected with the deep surface of the anterior longitudinal ligament, and so tie it to the edges of the bodies of the vertebrae and to the intervertebral discs. They blend behind with the expansions of the posterior longitudinal ligament, and so complete the casing round each amphiarthrodial joint. In the thoracic region, they overlie the radiate ligament, and in the lumbar they radiate toward the transverse processes. In the cervical region they are less well marked.
The articular capsules (fig. 259) which unite these processes are composed partly of yellow elastic tissue and partly of white fibrous tissue. In the cervical region only the medial side of the capsule is formed by the ligamenta flava, which in the thoracic and lumbar regions, however, extend anteriorly to the margins of the intervertebral foramina.
esses and the posterior roots of the transverse processes of two contiguous vertebra. In the thoracic region the fibres are shorter, and vertical in direction, and are attached to the bases of the transverse processes; in the lumbar, they are obhquely transverse. The articular capsules in the cervical region are the most lax, those in the lumbar region are rather tighter, and those in the thoracic region are the tightest.
The ligamenta flava (fig. 268) are thick plates of closely woven yellow elastic tissue, interposed between the laminae of two adjacent vertebrae. The first connects the epistropheus with the third cervical, and the last the fifth lumbar with
Ligamentum flavum
the sacrum. Each ligament extends from the medial and posterior edge of the intervertebral foramen on one side to a corresponding point on the other ; above, it is attached close to the inner margin of the inferior articular process and to a well-marked ridge on the inner surface of the laminae as far as the root of the spine; below, it is fixed close to the inner margin of the superior articular process and to the dorsal aspect of the upper edge of the laminae.
Thus each ligamentum flavum, besides filling up the interlaminar space, enters into the formation of two articular capsules; they do so to a greater extent in the thoracic and lumbar regions than in the cervical, where the articular processes are placed wider apart. When seen from the front after removing the bodies of the vertebrae, they are concave from side to side, but convex from above downward; they make a more decided transverse curve than the arches between which they are placed. This concavity is more marked in the thoracic, and still more in the lumbar region than in the cervical; in the lumbar region the hgamenta flava extend a short distance between the roots of the spinous process, blending with the interspinous ligament, and making a median sulcus when seen from the front; there is, however, no separation between the two parts. In the cervical region, where the spines are bifid, there is a median fissure in the yellow tissue which is filled up by fibro-areolar tissue. The ligaments are thickest and strongest in the lumbar region; narrow but strong in the thoracic; thinner, broader, and more membranous in the cervical region.
The supraspinous ligament (fig. 270) extends without interruption as a well-marked band of longitudinal fibres along the tips of the spines of the vertebrae fromthat of the seventh cervical downward till it ends on the median sacral crest.
Its more superiioial fibres are much longer than the deep. The deeper fibres pass over adjacent spines only, while the superficial overlie several. It is connected laterally with the aponeurotic structures of the back; indeed, in the lumbar region, where it is well marked, it
appears to result from the interweaving of the tendinous fibres of the several muscles which are attached to the tips of the spinous processes. In the dorsal region it is a round slender cord which is put on the stretch in flexion and relaxed in extension of the back.
The ligamentum nuchse, or the posterior cervical ligament (fig. 269), is the continuation in the neck of the supraspinous ligament, from which, however, it differs considerably. It is a slender vertical septum of an elongated triangular form, extending from the seventh cervical vertebra to the external protuberance and the crest of the occipital bone. Its anterior border is firmly attached to the tips of the spines of all the cervical vertebrte, including the posterior tubercle of the atlas, as well as to the occiput. Its posterior border gives origin to the trapezii, with the tendinous fibres of which muscle it blends. Its lateral, triangular surfaces afford numerous points of attachment for the posterior muscles of the head and neck.
In man it is rudimentary, and consists of elastic and white fibrous tissues. As seen in the horse, elephant, ox, and other pronograde mammals, it is a great and important elastic ligament, which even reaches along the thoracic part of the spinal column. In these animals it serves
rudimentary state in man is the direct consequence of his erect position.
The interspinous ligaments (fig. 270) are thin membranous structures which extend between the spines, and are connected with the ligamenta flava in front, and the supraspinous ligament behind.
The fibres pass obliquely from the root of one spine to the tip of the next; they thus decussate. They are best marked in the lumbar region, and are replaced by the well-developed inierspinales muscles in the cervical region.
The intertransverse ligaments are but poorly developed.
In the thoracic region they form small rounded bundles, and in the lumbar they are flat membranous bands, unimportant as bonds of union. They consist of fibres passing between the apices of the transverse processes. In the cervical region they are replaced by the intertransversarii muscles.
Movements. — The vertebral column is so formed of a number of bones and intervertebral discs as to serve many purposes. It is the axis of the skeleton; upon it the skull is supported; and with it the cavities of the trunk and the limbs are connected, As a fixed column it is capable of bearing great weight, and, through the elastic intervertebral substances, of resisting and breaking the transmission of shocks. Moreover, it is flexible. Now, the range of movements of the column as a whole is very considerable; but the movements between any two vertebrae are slight, so that motions of the spine may take place without any change in the shape of the column, and without any marked disturbance in the relative positions of the vertebrae. It is about the pulpy part of the intervertebral discs, which form a central elastic pivot or ball, upon which the middle of the vertebras rest, that these movements take place.
The amount of motion is everywhere limited by the common vertebral Ugaments, but it depends partly upon the width of the bodies of the vertebrae, and partly upon the depth of the discs, so that in the loins, where the bodies are large and wide, and the discs very thick, free motion is permitted; in the cervical region, though the discs are thinner, yet, as the bodies are smaller, almost equally free motion is allowed. As the ball-Uke pulpy part of the intervertebral disc is the centre of movement of each vertebra, it is obvious that the motion would be of a rolUng character in any direction but for the articular processes, wtiich serve also to give steadiness to the column and to assist in bearing the superincumbent weight. Were it not for these processes, the column, instead of being steady, endowed with the capacity of movement by muscular agency, would be tottering, requiring muscles to steady it. The influence of the articular processes in limiting the direction of incUnation will appear from a study of the movements in the three regions of the spine.
In the neck all movements are permitted and are free, except between the second and third cervical vertebrje, where they are slight, owing to the shallow intervertebral disc and the great prolongation of the anterior hp of the inferior surface of the body of the epistropheus, which checks forward flexion considerably. On the whole, however, extension and lateral inclination are more free and extensive in this than in any other region of the column, whilst flexion is more limited than in the lumbar region. Rotatory movements are also free, but take place, on account of the position and inclination of the articular facets, not, as in the thoracic region, round a vertical axis, but round an oblique axis, the articular process of one side gliding upward and forward and that of the opposite side downward and backward.
In the thoracic region, especially near its middle, antero-posterior flexion and extension are very slight; and, as the concavity of the curve here is forward, the flat and nearly vertical surfaces of the articular processes prevent anything like sliding in a curvilinear manner of the
one set of processes over the sharp upper edges of the other, which would be necessary for forward flexion. A fair amount of lateral inclination would be permitted but for the impediment offered by the ribs; while the position and direction of the articular processes allows rotation round a vertical axis which passes through the centres of the bodies of the vertebrae. This rotation is not very great, and is freer in the upper than in the lower part of the thoracic region.
In the lumbar region, extension and flexion are very free, especially between the third and fourth and fourth and fifth vertebrae, where the lumbar curve is sharpest; lateral inclination is also very free between these same vertebrae. It has been stated that the shape and position of the articular processes of the lumbar and the lower two or three dorsal are such as to prevent any rotation in these regions; but, owing to the fact that the inferior articular processes are not tightly embraced by the superior, so that the two sets of articular processes are not in contact on both sides of the bodies at the same time, there is always some space in which horizontal motion can occur round an axis drawn through the central part of the bodies and intervertebral discs, but it is very slight. Thus, the motions are most free in those regions of the column which have a convex curve forward, due to the shape of the intervertebral discs, where there are no bony waOs surrounding solid viscera, where the spinal canal is largest and its contents are less firmly attached, and where the pedicles and articular processes are more nearly on a transverse level with the posterior surface of the bodies of the vertebrae.
Nor must the uses of the ligamenta flava be forgotten: these useful structures — (1) complete the roofing-in of the vertebral canal, and yet at the same time permit an ever-changing variation in the width of the interlaminar spaces in flexion and extension; (2) they also restore the articulating surfaces to their normal position with regard to each other after movements of the column; (3) and by forming the medial portion of each articular capsule, they take the place of muscle in preventing it from being nipped between the articular surfaces during movement.
Muscles which take part in the movements of the vertebral column. — Flexors : When acting with their fellows of the opposite side. Rectus abdominis, infra-hyoid muscles (slightly) sterno-mastoid, external oblique, internal obHque, intercostals, scalenus anterior, psoas major and minor, longus colli, longus capitis (rectus capitis anterior major).
Extensors : When acting with their fellows of the opposite side. Sacro-spinalis, quadratus lumborum, semispinalis, multifidus, rotatores, interspinales, serrati posteriores, the splenius, and with the scapula fixed the levator scapulae and the upper fibres of the trapezius.
Muscles which help to incline the column to their own side. — Sacro-spinaUs, quadratus lumborum, semispinalis, multifidus, the intercostals helping to fix the ribs, the external and internal oblique muscles, levatores costarum, serrati posteriores, the scalenes, splenius cervicis, longus coUi (oblique part), rotatores, intertransversales, psoas, and with the scapula fixed the levator scapulae and the upper and lower fibres of the trapezius.
Muscles which rotate the column and turn the body to their own side. — Splenius cervicis, internal oblique (the ribs being fixed), serratus posterior inferior, and with the scapula fixed the lower fibres of the trapezius.
Muscles which rotate the column and turn the body to the opposite side. — Multifidus, semispinalis, external oblique, the lower oblique fibres of the longus colli, and with the scapula and humerus fixed the latissimus dorsi and trapezius.
As in the intervertebral articulations, so in the union of the first portion of the sacrum with the last lumbar vertebra, there are two sets of joints — viz. (a) a synchondrosis, between the bodies and intervertebral disc; and (6) a pair of arthrodial joints, between the articular processes. The union is effected by the following ligaments, which are common to the vertebral column: — (i) anterior, and (ii) posterior longitudinal; (iii) lateral or short vertebral; (iv) capsular; (v) ligamenta flava; (vi) supraspinous and (vii) interspinous ligaments. Two special accessory ligaments on either side, viz., the sacro-lumbar and the iliolumbar, connect the pelvis with the fourth and fifth lumbar vertebrae.
The sacro-lumbar ligament (fig. 271) is strong, and triangular in shape. Its apex is above and medial, being attached to the whole of the lower border and front surface of the transverse process of the fifth liunbar vertebra, as well as to the pedicle and body. It is intimately blended with the ilio-lumbar ligament. Below, it has a wide, fan-shaped attachment, extending from the edge of the iliolumbar ligament forward to the brim of the true pelvis; blending with the periosteum on the base of the sacrum and in the iliac fossa, and with the superior sacroiliac ligament.
By its sharp medial border it Umits laterally the foramen for the last lumbar nerve. It is pierced by two large foramina, which transmit arteries to the saoro-iliac synchondrosis. This ligament is in series with the intertransverse ligaments of the spinal column. It is sometimes described as a part of the ilio-lumbar ligament.
connecting the fourth and fifth lumbar vertebrae with the iliac crest.
It springs from the front surface of the transverse process of the fifth lumbar vertebra as far as the body, by a strong fasciculus from the posterior surface of the process near the tip, and also from the front surface and lower edge of the transverse process and pedicle of the fourth lumbar vertebra, as far medialward as the body. Between these two lumbar vertebrae it is inseparable from the intertransverse hgament.
At its origin from the transverse process of the fifth lumbar vertebra it is closely interwoven with the sacro-lumbar ligament, and some of its iibres spread downward on to the body of the fifth vertebra, while others ascend to the disc above. At the pelvis it is attached to the inner lip of the crest of the ilium for about two inches (5 cm.) . The highest fibres at the column form the upper edge of the ligament at the pelvis, those which come from the posterior portion of the transverse process of the fifth lumbar vertebra forming the lower, while the fibres from the front of the same process pass nearly horizontally lateralward. Near the column the surfaces
look directly backward and forward, but at the ilium the ligament gets somewhat twisted, so that the posterior surface looks a little upward, and the anterior looks a Mttle downward. The anterior surface forms part of the posterior boundary of the major (false) pelvis, and overlies the upper part of the posterior sacro-iliao ligament; the posterior surface forms part of the floor of the spinal groove, and gives origin to the mullifidus muscle. Of the borders, the upper is oblique, has the anterior lamella of the lumbar fascia attached to it, and gives origin to the quadralus lumborum; the lower is horizontal, and is adjacent to the upper edge of the sacrolumbar ligament; while the medial is crescentic, and forms the lateral boundary of a foramen through which the fourth lumbar nerve passes.
lumbar nerves.
Movements. — The angle formed by the sacrum with the spinal column is called the sacrovertebral angle. The pelvic inclination does not depend entirely upon this angle, but in great part upon the obUquity of the co.xal (innominate) bones to the sacrum, so that in males in whom the average pelvic obliquity is a Uttle greater, the average sacro-vertebral angle is considerably less than in females.
The sacro-vertebral angle in the male shows that there is a greater and more sudden change in direction at the sacro-vertebral union than in the female. A part of this change in direction is due to the greater thickness in the anterior part of the intervertebral fibro-cartilage between the last lumbar vertebra and the sacrum. Owing to the greater thickness of the intervertebral
disc here than elsewhere, the movements permitted at this joint are very free, being freer than those between any two lumbar vertebrEe. As the diameter of the two contiguous bones is less in the sagittal than in the frontal plane, the forward and backward motions are much freer than those from side to side. The backward and forward motions take place every time the sitting is exchanged for the standing position, and the standing for the sitting posture; in rising, the back is extended on the sacrum at the sacro-lumbar union; in sitting down it is flexed.
The articular processes provide for the ghding movement incidental to the extension, flexion, and lateral movements; they also allow some horizontal movement, necessary for the rotation of the vertebral column on the pelvis, or pelvis on the column. The inferior articular processes of the fifth differ considerably from the inferior processes in the rest of the lumbar vertebrae, and in direction they resemble somewhat those of the cervical vertebrae; while the superior articular processes of the sacrum differ in a similar degree from the superior processes of the lumbar vertebrae. This difference allows for the freer rotation which occurs at this joint.
As already stated, the movements at the sacro-vertebral joint are the same as those in other parts of the spinal column, but more extensive, and the muscles which produce the movements are those mentioned in the preceding groups which cross the plane of the articulation.
It is now generally admitted that the sacro-iliac joint is a diarthrosis, the articular surface of each bone being covered with a layer of cartilage, whilst the cavity of the joint is a narrow cleft and the capsule is extremely thick posteriorly. The cartilage on the sacrum is much thicker than that on the ilium and the cartilages are sometimes bound together here and there by fibrous strands. The different character of the joint in the two sexes should be noted. Briefly, the female joint has strong ligamentous bonds with but little bony apposition, while the male joint gains its strength by virtue of extensive areas of bony contact and a slighter development of ligaments. This difference is, of course, a physiological one; for some laxity of the joint is demanded during pregnancy and labour. The bones which enter into the joint are the sacrum and ilium, and they are bound together by the following ligaments: —
The anterior sacro-iliac ligament (figs. 271 and 272) consists of well-marked glistening fibres which pass above into the superior, and below into the inferior, ligaments. It extends from the first three bones of the sacrum to the ilium between the brim of the pelvis minor and the great sciatic notch, blending with the periosteum of the sacrum and ilium as it passes away from the united edges of the bones.
The superior sacro-iliac ligament (figs. 271 and 272) extends across the upper margins of the joint, from the ala of the sacrum to the iliac fossa, being well marked along the brim of the pelvis, where it is thickened by some closely packed fibres. Behind, it is far stronger, especially beneath the transverse process of the fifth lumbar vertebra. This ligament is connected with the strong sacrolumbar ligament, which spreads lateralward and forward over the joint to reach the iliac fossa and terminal line. By some authors it is described as a part of the ilio-lumbar ligament.
The posterior sacro-iliac ligament is extremely strong and consists essentially of two sets of fibres, deep and superficial. The deep fibres (short posterior sacroiliac ligament) pass downward and medialward from the rough area of the
ilium behind the auricular surface to the back of the lateral mass of the sacrum, both lateral to and between the upper foramina and to the upper sacral articular process, and the area between it and the first sacral foramen. The deepest fibres of this group constitute the so-called interosseous ligament. The more superficial fibres (long posterior sacro-iliac ligament) are oblique or vertical, and pass from the posterior superior iliac spine to the second, third, and fourth tubercles on the back of the sacrum, a more or less well-defined band which goes to the third and fourth sacral tubercles being called sometimes the oblique saero-iliac band and sometimes the long straight band.
The inferior sacro-iliac ligament (fig. 272) is covered behind by the upper end of the sacro-tuberous ligament; it consists of strong fibres extending from the lateral border of the sacrum below the articular facet to the posterior iliac spines; some of the fibres are attached to the deep surface of the ilium and join the interosseous ligament.
The interosseous ligament is the strongest of all, and consists of fibres of different lengths passing in various directions between the two bones. Immediately above the interspinous notch of the ilium the fibres of this ligament are very strong, and form an open network, in the interstices of which is a quantity of fat in which the articular vessels ramify.
Tlie ear-shaped cartilaginous plate, which unites the bones firmly, is accurately applied to the auricular surfaces of the sacrum and ilium. It is about one-twelfth of an inch (2 mm.) thick in the centre, but becomes thinner toward the edges. Though closely adherent to the bones, it tears away from one entirely, or from both partially, on the application of violence, sometimes breaking irregularly so that the greater portion remains connected with one bone, leaving the other bone rough and bare. It is usually one mass, and is only occasionally formed of two plates with a synovial cavity between them.
Because of the occasional presence of a more or less extensive synovial ca^dty within the fibro-cartilage, and also of a synovial lining to the Ugaments passing in front and behind the articulation, the term 'diarthro-amphiarthrosis' has been given to this joint, and also to the sympliysis pubis. Testut mentions certain folds of sjiiovial membrane filling up gaps which here and there occur at the margin of the fibro-cartilage but they are not usually seen.
The sacro-tuberous (great sciatic) ligament (figs. 271, 272, and 273) is attached above to the posterior extremity of the crest of the ilium and the lateral aspect of the posterior iliac spines. From this attachment some of its fibres
pass downwai'd and backward to be attached to the lateral borders and posterior surfaces of the lower three sacral vertebrae and upper two segments of the coccyx; while others, after passing for a certain distance backward, curve forward and downward to the ischium, forming the anterior free margin of the ligament where it limits posteriorly the sciatic foramina. These fibres are joined by others which arise from the posterior surfaces of the lower three sacral vertebrse and upper pieces of the coccyx. At the ischium it is fixed to the medial border of the tuberosity, and sends a thin sharp process upward along the ramus of the ischium which is called the falciform process (fig. 273), and is a prolongation of the posterior edge of the ligament.
A great many fibres pass on directly into the tendon of the biceps muscle, so that traction on this muscle braces up the whole ligament, and the coccyx is thus made to move on the sacrum. The ligament may not unfairly be described as a tendinous expansion of the muscle, whereby its action is extended and a more advantageous leverage given. It is broad and flat at its attached ends, but narrower and thicker in the centre, looking like two triangular expansions-
joined by a flat band, the larger triangle being at the ilium, and the smaller at the ischium^ The fibres of the ligament are twisted upon its axis at the narrow part, so that some of thesuperior fibres pass to the lower border.
The posterior surface gives origin to the gluteus maximus muscle, and on it ramify the loop; from the posterior branches of the sacral nerves; its anterior surface is closely connected at its origin ,with the sacro-spinous ligament, and some fibres of the piriformis muscle arise from its below the obturator internus passes out of the pelvis under its cover, and the internal pudic vessels and nerve pass in. At the ilium, its posterior edge is continuous with the vertebra, aponeurosis; while to the anterior edge is attached the thick fascia covering the gluteus mediusl The obturator fascia is attached to its falciform edge. It is pierced by the coccygeal branches of the inferior gluteal {sciatic) artery and the inferior clunial {perforating cutaneous) nerve from the second and third sacral.
The sacro-spinous (small sciatic) ligament (figs. 271, 272, and 273) is triangular and thin, springing by a broad base from the lateral border of the sacrum and coccyx, from the front of the sacrum both above and below the level of the fourth sacral foramen, and from the coccyx nearly as far as its tip. By its apex it is attached to the front surface and the borders of the ischial spine as far outward as its base. Its fibres decussate so that the lower ones at the coccyx become the highest at the ischial spine; muscular fibres are often seen intermingled with the ligamentous.
Its front surface gives attachment to the coccygeus muscle, which overlies it. Behind, it is connected with, and hidden by, the sacro-tuberous ligament, so that only the lateral inch or less (2 cm.) and a small part of its attachment to the coccyx can be seen; the internal pudic nerve also passes over the posterior surface.
posterior divisions of the first and second sacral nerves.
Movements. — Recent investigations have shown that in spite of the interlocking of the articular surfaces and the strong ligaments connecting the bones together a slight amount of movement, both a gUding and rotatory, does occur at the sacro-iliac joint. The gliding movement is both up and down, and forward and backward, and the latter is associated with a slight rotation round a transverse axis which passes through the upper tubercles on the back of the sacrum. The movement is but small in extent, nevertheless as the base of the sacrum moves
turned down
downward and forward the conjugate (antero-posterior) diameter of the pelvic inlet is diminished and at the same time, as the coccyx moves up and back, the conjugate diameter of the outlet is increased. This rotatory movement is limited principally by the sacro-sciatic (sacrotuberous and sacro-spinous) Ugaments which prevent any extensive upward and backward movement of the coccyx and lower part of the sacrum.
Downward displacement of the sacrum when the body is in the sitting posture is prevented not only by the surrounding hgaments, but also by the wedge-like character of the sacrum, which is broader above than below. Downward and forward displacement of the sacrum in the erect posture is prevented by the ligaments and more particularly by the posterior sacroiliac bands, while backward displacement would be hindered by the breadth of the anterior as contrasted with the posterior part of the sacrum as well as by the anterior ligaments.
Relations. — The sacro-ihac joint is in relation above with psoas and iUaous. In front it is in relation at its upper part with the hypogastric vessels and obturator nerve, and at its lower part with the piriformis muscle.
The last piece of the sacrum and first piece of the coccyx enter into this union [symphysis sacrococcygea] and are bound together by the following ligaments : — Anterior sacro-coccygeal. Deep posterior sacro-coccygeal.
The intervertebral fibro -cartilage is a small oval disc, three-quarters of an inch (about 2 cm.) wide, and a little less from before backward, closely connected with the surrounding ligaments. It resembles the other discs in structure, but is softer and more jelly-like, though the laminse of the fibrous portion are well marked.
The anterior sacro-coccygeal ligament is a prolongation of the glistening fibrous structure on the front of the sacrima. It is really the lower extremity of the anterior longitudinal ligament, which is thicker over this joint than over the central part of either of the bones.
The posterior sacro-coccygeal ligament (fig. 274) is divided into two layers of which one (the deep) is a direct continuation of the posterior longitudinal ligament of the column, consisting of a narrow band of closely packed fibres, which become blended at the lower border of the first segment of the coccyx with the filum terminate and deep posterior ligament.
The superficial layer of the posterior sacro-coccygeal ligament (or supracornual ligament), (fig. 274) is the prolongation of the supraspinous which becomes inseparably blended with the aponeurosis of the sacro-spinalis (erector spince) opposite the laminse of the third sacral vertebra, and is thus prolonged downward upon the back of the coccyx, passing over and roofing in the lower end of the spinal canal where the laminge are deficient.
The median fibres (the supraspinous ligament) extend over the back of the coccyx to its tip, blending with the deep fibres of the posterior sacro-coccygeal ligament and filum terminale; the deeper fibres run across from the stunted laminae on one side to the next below on the opposite side, and from the sacral cornua on one side to the coccygeal on the opposite, some passing between the two cornua of the same side, and bridging the aperture through which the fifth sacral nerve passes. Its posterior surface gives origin to the gluteus inaximus muscle.
The lateral sacro-coccygeal or intertransverse ligament (fig. 274) is merely a quantity of fibrous tissue which passes from the transverse process of the coccyx to the lateral edge of the sacrum below its angle. It is connected with the saerosciatic ligaments at their attachments, and the fifth sacral nerve escapes behind it. It is perforated by twigs from the lateral sacral artery and the coccygeal nerve.
The nerves come from the fourth and fifth sacral and coccygeal nerves.
The movements permitted at this joint are of a simple forward and backward, or hingelike character. In the act of defecation, the bone is pushed back by the faecal mass, and, in parturition, by the foetus; but this backward movement is controlled by the upward and forward puU of the levator ani and Qoccygeus. The external sphincter also tends to puU the coccyx forward.
The several segments of the coccyx are held together by the anterior and posterior longitudinal ligaments, which completely cover the bony nodules on their anterior and posterior aspects. Laterally, the sacro-sciatic ligaments, being attached to nearly the whole length of the coccyx, serve to connect them. Between the first and second pieces of the coccyx there is a very perfect amphiarthrodial joint, with a well-marked intervertebral substance.
Movements. — But Uttle movement occurs as a rule at the sacro-coccygeal and intercoccygeal joints, but when the head of the child is passing through the pelyic outlet at birth, the tip of the coccyx is displaced backward, it may be to the extent of one inch.
The bones entering into this joint are the pubic portions of the hip-bones. This joint is shorter and broader in the female than in the male. The ligaments, which completely surround the articulation, are : —
Interpubic cartilage.
The superior ligament (figs. 275 and 276) is a well-marked stratum of yellowish fibres which extends lateralward along the crest of the pubis on each side, blending in the middle line with the interosseous cartilage.
consists of little more than thickened periosteum.
Near the uipper part is a band of strong fibres, reaching the whole width of the pubic bones, and continuous with the thickened periosteal fibres along the terminal line. Below, many of the upper and superficial fibres of the arcuate ligament ascend over the back of the joint, and interlace across the median line with fibres from the opposite side nearly as high as the middle of the symphysis.
The anterior ligament (figs. 275 and 276) is thick and strong, and is closely connected with the fascial covering of the muscles arising from the body of the pubis. It consists of several strata of thick, decussating fibres of different degrees of obliquity, the superficial being the most oblique, and extending lowest over the joint.
The most superficial descending fibres extend from the upper border of the pubis, cross others from the opposite side about the middle of the symphysis, and are attached to the ramus of the opposite bone. The most superficial ascending fibres come from the arcuate ligament,
arch upward,"and decussate with other fibres across the middle line, and are lost on the opposite side beneath the descending set. There is another deeper set of descending fibres which arise below the angle, but do not descend so far as the superficial; and a deeper set of ascending, which decussate, and reach higher than the superficial set, and are connected with the arcuate ligament. Some few transverse fibres pass from side to side, especially above and below^the points of decussation.
The arcuate (inferior or subpubic) ligament (figs. 275, 276, and 277) is a thick, arch-like band of closety packed fibres which fills up the angle between the pubic rami, and forms a smooth, rounded summit to the pubic arch. On section, it is yellowish in colour and three-eighths of an inch (1 cm.) thick in the middle line; it is inseparably connected with the interpubic cartilage.
Both on the front and back aspects of the joint it gives off decussating fibres, which, by their interlacement over the anterior and posterior ligaments of the symphysis, add very materially to its security. In fact, the ligament may be said to split superiorly into two layers, one passing over the front, and the other over the back, of the articulation.
The interpubic fibro -cartilage varies in thickness in different subjects, but is thicker in the female than in the male. It is thicker in front than behind, and projects beyond the edges of the bones, especially posteriorly (see fig. 277), blending intimately with the ligaments at its margins. It is sometimes uninterruptedly woven throughout, but at others has an elongated narrow fissure, partially dividing the cartilage into two plates, with a little fluid in the interspace
When this cavity is large, especially if it reaches or approaches very near to the circumference of the cartilage (which, however, it very rarely does), it is thought by some anatomists that it more nearly resembles a diarthrodial than an amphiarthrodial joint, and it is then classed with the sacro-Uiac joint under similar conditions, as 'diarthroamphiarthrosis.' The interosseous cartilage is intimately adherent to the layer of hyaline qartUage which covers the medial surface of each pubic bone; the osseous surface is ridged to give a firmer attachment; and, on forcing the bones apart, it does not frequently spht into two plates, but is torn from the bone on one side or the other.
The movements amount only to a slight yielding of the cartilage; neithermuscular force nor extrinsic forces produce any appreciable movement in the ordinary condition. Occasionally, as the result of child-bearing, the joint becomes unnaturally loose, and then waMng and standing are painfully unsteady. It is known that, during pregnancy and parturition, the
symphyseal cartilage becomes softer and more vascular, so as to permit the temporary enlargement of the pelvis; but it must be remembered that the fibres of the obhque muscles decussate and thus, during labour, while they force the head of the fcetus down, they strengthen the joint by bracing the bones more tightly together.
with the vertebrae.
(6) The costo-transverse, or the articulation of the tubercle (of each of the first ten ribs) with the transverse process of the lower of the two vertebree, with which the head of the rib articulates: i.e., the one bearing its own number, as the first rib with the first thoracic vertebra, the second rib with the second thoracic vertebra, and so on.
It is a very perfect joint, into the formation of which the head of the rib and two vertebrae, with the intervertebral disc between them, enter. In the case of the first, tenth, eleventh, and twelfth ribs, it is formed by the head of the rib articulating with a single vertebra.
Radiate.
The articular capsule (fig. 279) consists of short, strong, woolly fibres, completely surrounding the joint, which are attached to the bones and intervertebral substances, a little beyond their articular margins.
At its upper part it reaches through the intervertebral foramen toward the back of the bodies of the vertebrae, being strengthened here by fibres which at intervals connect the anterior with the posterior longitudinal ligaments. The lower fibres extend downward nearly to the demi-faoet (costal pit) of the rib below; behind, it is continuous with the neck ligament, and in front is overlaid by the radiate.
The interarticular ligament (fig. 280) consists of short, strong fibres, closely interwoven with the outermost ring of the intervertebral disc, and attached to the transverse ridge separating the articular facets on the head of the rib. It completely divides the articulations into two parts, but does not brace the rib tightly to the spine, being loose enough to allow a moderate amount of rotation
of the first, tenth, eleventh, and twelfth ribs.
The radiate (or stellate) ligament, a thickening of the anterior part of the capsule (figs. 280 and 281), is the most striking of all, and consists of bright, pearly-white fibres attached to the anterior surface, and upper and lower borders of the neck of the rib, a little way beyond the articular facet; from this they radiate upward, forward, and downward, so as to form a continuous layer of distinct and sharply defined fibres.
The middle fibres run straight forward to be attached to the intervertebral disc; the upper ascend to the lower half of the lateral surface of the vertebra above, and the lower descend to the upper half of the vertebra below. The radiate ligament is overlapped on the vertebral bodies by the lateral (short) vertebral ligaments.
In the case of the first, tenth, eleventh, and twelfth ribs, each of which articulates with one vertebra, the ligament is not quite so distinctly radiate, but even in these the ascending fibres reach the vertebra above that with which the rib articulates.
The synovial membranes (fig. 281) consist of two closed sacs which do not communicate: one above, and the other below, the interarticular ligament. In the case of the first, tenth, eleventh, and twelfth articulations, there is but one synovial membrane, as these joints have no interarticular ligament.
These joints approach most nearly in their movements to the condylarthroses.
The movements are ginglymoid in character, consisting of a slight degree of elevation and depression around an obliquely horizontal axis corresponding with the interarticular ligament; there is also a slight amount of forward and backward gliding; and a slight degree of screwing or rotatory movement is also possible . There is a considerable difference in the degree of mobility of the different ribs, for while the first rib is almost immobile except in a very deep inspiration, the mobility of the others increases from the second to the last; the two floating ribs being the most mobile of all. The head of the rib is the most fixed point of the costal arch, and upon it the whole arch rotates; the interarticular ligament allows only a very limited amount of flexion and extension (i. e., elevation and depression), and of gliding. Gliding is checked by the radiate ligament.
In inspiration, the rib is elevated, and glides forward in its socket, too great elevation being checked not only by the ligaments, but also by the overhanging upper edge of the cavity itself. In expiration, the rib is depressed, and glides backward in its cavity.
This joint is formed by the tubercle of the rib articulating with the anterior part of the tip of the transverse process. The eleventh and twelfth ribs are devoid of these joints, for the tubercles of these ribs are absent, and the transverse processes of the eleventh and twelfth thoracic vertebrae are rudimentary.
The articular capsule (figs. 279 and 281) forms a thin, loose, fibrous envelope to the synovial membrane. Its fibres are attached to the bones just beyond the articular margins, and are thickest below, where they are not strengthened by any other structure. It is connected medially with the neck ligament, above with the costo-transverse, and laterally with the tubercular (posterior costotransverse) ligaments. The eleventh and twelfth ribs are unprovided with costotransverse capsules.
The neck ligament [lig. colli costae] (middle costo-transverse, or interosseous ligament) (fig. 281), consists of short fibres passing between the back of the neck of the rib and front of the transverse process, with which the tubercle articulates. It extends from the capsule of the capitular joint to that of the costo-transverse. It is best seen on horizontal section through the bones. In the eleventh and twelfth ribs this ligament is rudimentary.
The tubercular ligament (posterior costo-transverse) (fig. 281) is a short but thick, strong, and broad ligament, which extends laterally and upward from the extremity of the transverse process to the non-articular surface of the tubercle of the corresponding rib. The eleventh and twelfth ribs have no posterior ligament.
The (superior) costo-transverse ligament (fig. 280) is a strong, broad band of fibres which ascends laterally from the crest on the upper border of the neck of the rib, to the lower border of the transverse process above. A few scattered posterior fibres pass upward and medially from the neck to the transverse process. The costo-transverse ligament is subdivided into a stronger anterior portion (anterior costo-transverse ligament) best seen from the front (fig. 280) , and a weaker posterior portion (posterior costo-transverse ligament). Its medial border bounds the foramen through which the posterior branches of the intercostal vessels and nerves pass. To the lateral border is attached the thin aponeu-
rosis covering the external intercostals. Its anterior surface is in relation with the intercostal vessels and nerve; the posterior with the longissimus dor si. The first rib has no (superior) costo-transverse ligament.
The movements which take place at these joints are limited to a gliding of the tubercle of the rib upon the transverse process. The exact position of the facet on the transverse process varies slightly from above downward, being placed higher on the processes of the lower vertebrae. The plane of movement in most of the costo-transverse joints is inclined upward and backward in inspiration, and downward and forward in expiration. The point round which these movements occur is the head of the rib, so that the tubercle of the rib gUdes upon the transverse process in the circumference of a circle, the centre of which is at the capitular joint.
The sternum being composed, in the adult, of three distinct pieces — the manubrium, body, and the xiphoid process — has two articulations, viz., the superior, which unites the manubrium with the body (gladiolus), and the inferior, which unites the body with the xiphoid.
The lower border of the manubrium and the upper border of the body of the sternum present oval-shaped, fiat surfaces, with their long axes transverse, and covered with a thin layer of hyaline cartilage. An interosseous fibro-cartilage is interposed between the bony surfaces: it corresponds exactly in shape and intimately adheres to them. At each lateral border this fibro-cartilage enters into the formation of the second chondro-sternal articulation (fig. 282).
In consistence it varies, being in some oases uniform throughout, in others softer in the centre than at the circumference, and in others again an oval-shaped synovial cavity is found toward its anterior part. When such a cavity exists in the fibro-cartilage this joint has a remote resemblance to the diarthroses, and is classed, with the sacro-iliac joint and the symphysis pubis under similar conditions, as 'diarthro-amphiarthrosis.'
The periosteum passes uninterruptedly over the joint from one segment of the sternum to the other, forming a kind of capsular ligament [membrana sterni]. This capsule is strengthened, especially on its pos'erior aspect, by longitudinal ligamentous fibres as well as by the radiating and decussating fibres of the chondro-sternal ligaments.
The gladiolus is joined to the xiphoid cartilage by a thick investing membrane, by anterior and posterior longitudinal fibres, and by radiating fibres of the sixth and seventh chondro-sternal ligaments. The costo-xiphoid ligament also connects the xiphoid with the anterior surface of the sixth and seventh costal cartilages, and thus indirectly with the gladiolus; and some fine fibro-areolar tissue also connects the xiphoid with the back of the seventh costal cartilage.
The junction of the xiphoid with the sternum is on a level somewhat posterior to the junction of the seventh costal cartilage with the sternum. The union is a synchondrosis, each bone being covered by hyahne cartilage which is connected with the intervening fibro-cartilage plate.
These articulations are between the lateral borders of the sternum and the ends of the costal cartilages. The union of the first rib with the sternum is synchondrodial, and therefore forms an exception to the others. From the second to the seventh inclusive, the articulations have the following ligaments, which together form a complete capsule: —
The radiate (anterior) sterno-costal ligament (fig. 282) is a triangular band composed of strong fibres which cover the medial half-inch of the front of the costal cartilage, and radiate upward and downward upon the front of the sternum. Some of the fibres decussate across the middle line with fibres of the opposite ligament. At its upper and lower borders it is in contact with the superior and inferior ligaments respectively.
The posterior sterno-costal ligament consists of little more than a thickening of the fibrous envelopes of the bone and cartilage, the joint being completed behind by a continuity of perichondrium with periostemn.
The superior and inferior ligaments are strong, well-marked bands, which pass from the upper and lower borders respectively of the costal cartilage to the lateral edges of the sternum. The sixth and seventh cartilages are so close that the superior ligament of the seventh is blended ^^^th the inferior of the sixth rib.
Deeper than the fibres of these ligaments are short fibres passing from the margins of the sternal facets to the edges of the facets on the cartilages; they are most distinct in the front and lower part of the joint, and may encroach so much upon the synovial cavity as to reduce it to a very small size, or almost obliterate it. This occurs mostly in the case of the sixth and seventh joints, especially the latter.
The interarticular ligament (fig. 282) is by no means constant, but is usually present in the second joint on one, if not on both sides of the same subject. It consists of a strong transverse bundle of fibres passing from the ridge on the facet on the cartilage to the fibrous substance between the manubrium and body; sometimes the upper part of the synovial cavity is partially or entirely obliterated by short, fine, ligamentous fibres.
The costo-xiphoid ligament (fig. 282) is a strong flat band of fibres passing obliquely upward and laterally from the front surface of the xiphoid cartilage to the anterior surface of the sternal end of the seventh costal cartilage, and most frequently to that of the sixth also.
Synovial membranes. — -The union of the first cartilage with the sternum being synchondrodial, it has no synovial membrane; the second has usually two, separated by the interarticular Ugament. The rest usually have one synovial membrane, which may occasionally be subdivided into two (fig. 2S2).
the nerves come from the anterior branches of the interoostals.
Movements. — -Excepting the first, the chondro-sternal joints are ginglymoid, but the motion of which they are capable is verj' limited. It consists of a hinge-like action in two directions: first, there is a slight amount of elevation and depression which takes place round a transverse axis, and, secondly, there is some forward and backward movement round an obliquely vertical axis. In inspiration the cartilage is elevated, the lowest part of its articular facet is pressed into the sternal socket, and the sternum is thrust forward so that the upper
A little in front of the point where the costal cartilages bend upward toward the median line the sixth is united with the seventh, the seventh with the eighth, the eighth with the ninth, and the ninth with the tenth.
At this point each of the cartilages from the sixth to the ninth inclusive is deeper than elsewhere, owing to the projection downward from its lower edge of a broad blunt process, which comes into contact with the cartilage next below. Each of the apposed surfaces is smooth.
MOVEMENTS OF THE THORAX
and they are connected at their margins by ligamentous tissue, which forms a complete capsule for the articulation, and is hned by a synovial membrane (fig. 282). The largest of these cavities is between the seventh and eighth; those between the eighth and ninth, and ninth and tenth, are smaller, and are not free to play upon each other in the whole of their extent, being held together by ligamentous tissue at theii' anterior margins. Sometimes this fibrous tissue completely obliterates the synovial cavity.
Movements. — -By means of the costal cartilages and interchondral joints, strength with elasticity is given to the wall of the trunk at a part where the cartilages are the only firm structures in its composition; while a slight gliding movement is permitted between the costal cartilages themselves, which takes place round an axis corresponding to the long axis of the cartilages. By this means, the outward projection of the lower part of the thoracic wall is increased by deep inspiration.
Before describing these movements as a <vhole, it must be premised that there are somt few modifications in the movements of certain ribs resulting from their shape. Thus the firs rib (and to a less extent the second also), which is flat on its upper and lower surfaces, revolves on a transverse axis drawn through the oosto-vertebral and costo-transverse joints. During inspiration and expiration, the anterior extremities of the first pair of costal arches play up and down, the tubercles and the heads of the ribs acting in a hinge-like manner, the latter having also a sHght screwing motion. By this movement the anterior ends of the costal arches are simply raised or depressed, and the sternum pushed a little forward; it may be likened to the movement of a pump-handle, as in fig. 283, a, b.
ribs rise nearly as much as the extremities themselves. In this'movement the tubercles of the ribs glide upward and backward in inspiration, and downward and forward in expiration; and the movement may be likened to that of a bucket handle, as in fig. 283, A, B.
During inspiration, the cavity of the thorax is increased in every direction. The anteroposterior diameter is increased by the thrusting forward of the sternum, caused by the elevation of the costal cartilages and fore part of the ribs, whereby they are brought to nearly the same level as the heads of the ribs. The transverse diameter is increased: (i) Behind, by the elevation of the middle part of the ribs; for when at rest the mid-part of the rib is on a lower level than either the costo-vertebral or chondro-sternal articulations. Owing to this obUquity the transverse diameter is increased when the rib is raised, and the increase is proportionate to the degree of obliquity, (ii) By the eversion of the lower border of the costal arch, which tuTns outward as the arch is raised, (iii) The transverse diameter is increased in front by the abduction of the anterior extremity of the rib at the same time as it is elevated and thrust forward.
The increase in the vertical diameter of the thorax is due to the elevation of the ribs, especially the upper ones, and the consequent widening of the intercostal spaces; but the chief increase in this direction is due to the descent of the diaphragm.
The greatest increase both in the antero-posterior and transverse diameters takes place where the ribs are longest, most oblique, and most curved at theu' angles, and where the bulkiest part of the lung is enclosed. This is on a level with the sixth, seventh, and eighth ribs.
At the lower part of the thorax, where the ribs have no relation to the lungs, and do not affect respiration directly by their movements, it is important that the costal arches should be thrown well outward in order to counteract the compression of the abdominal viscera by the contraction of the diaphragm.
Muscles which take part in the movements of inspiration. — (a) Ordinary inspiration; The scalenes, serratus posterior superior, the external and internal (?) intercostals, the diaphragm; the quadratus lumborum and serratus posterior inferior fixing the lower ribs, possibly the posterior fibres of the external oblique also helping to fix the lower ribs, (b) Extraordinary inspiration: The superior extremities are raised and fixed. The cervical part of the vertebral column and the head are extended, and in addition to the muscles of ordinary inspiration, the following
muscles also come into play: The pectoralis minor, the muscles which extend the head and the cervical part of the vertebral column, the sterno-mastoid and the supra- and infra-hyoid muscles, the lower fibres of the pectoralis major, some of the lower fibres of the serratus anterior, and, when the clavicle is fixed, the subclavius.
Expiration is produced by the elasticity of the lungs and the weight of the thorax, aided by the elastic reaction and contraction of the external and internal oblique muscles, the recti and pyramidales, the transversus abdominis, and the levatores ani and coccygei. In forcible expiration all muscles which depress the ribs and reduce the dimensions of the abdomen are thrown into action. The internal interoostals probably tend to contract the thorax, excepting, the parts between the costal cartilages, which tend to expand the thorax.
At this joint the large medial end of the clavicle is united to the superior angle of the manubrium sterni, the first costal cartilage also assisting to support the clavicle. It is the only joint between the upper extremity and the trunk, and takes part in all the movements of the upper limb. Looking at the bones, one would say that they were in no waj^ adapted to articulate with one another, and yet they assist in constructing a joint of security, strength, and importance. The bones are nowhere in actual contact, being completely separated by an articular disc. The interval between the joints of the two sides varies from one inch to an inch and a half (2.5-4 cm.). The ligaments of this joint are: —
The articular capsule (fig. 284) consists of fibres, having varying directions and being of various strength and thickness, which completely surround the articulation, and are firmly connected with the edges of the interarticular fibrocartilage.
The fibres at the back of the joint, sometimes styled the posterior stemo-clavicular ligament, are stronger than those in front or below, and consist of two sets: a superficial, passing upward and laterally from the manubrium sterni, to the projecting posterior edge of the end of the clavicle, a few being prolonged onward upon the posterior surface of the bone. A deeper set of fibres, especiallj^ thick and numerous below the clavicle, connect the interarticular cartilage with the clavicle and with the sternum, but do not extend from one bone to the other. The fibres in front, the anterior sterno -clavicular ligament, are well marked, but more lax and less tough than the posterior, and are overlaid by the tendinous sternal origin of the sternomastoid, the fibres of which run parallel to those of the ligament. They extend obliquely upward and laterally from the margin of the sternal facet to the anterior surface of the clavicle some little distance from the articular margin. The fibres which cover in the joint below are short, woolly, and consist more of fibro-areolar tissue than true fibrous tissue; they extend from the upper border of the first costal cartilage to the lower border of the clavicle just lateral to the articular margin, and fill up the gap between it and the costo-clavicular ligament. The superior portion consists of short tough fibres passing from the sternum to the articular disc; and of others welding the fibro-cartilage to the upper edge of the clavicle, onlj' a few of them passing from the clavicle direct to the sternum.
inch (6 mm.) deep with the concavity upward, its upper border tapering to a narrow, almost sharp edge. It is connected with the posterior superior angle of the sternal extremity of each clavicle, and with the fibres which weld the interarticular cartilage to the clavicle; and then passes across from clavicle to clavicle along the posterior aspect of the upper border of the manubrium sterni. The lowest fibres are attached to the sternum, and join the posterior fibres of the capsule of each joint. In the middle line, between the ligament and the sternum, there is an aperture for the passage of a small artery and vein.
In addition to the interclavicular ligament Mr. Carwardine ("Journal of Anatomy and Physiology," vol. 7, new series, p. 232) has described a special band of the upper portion of the sterno-clavioular capsule which he proposes to name the 'suprasternal hgament.' It descends from the upper border of the sternal end of the clavicle to the upper border of the sternum, and is of special importance as it encloses the suprasternal bones, when these rudiments are present.
The costo -clavicular or rhomboid ligament (fig. 284) is a strong dense band, composed of fine fibres massed together into a membranous structure. It extends from the upper (medial) border of the first costal cartilage (and rib),
upward, backward, and distinctly laterally to the costal tuberosity on the under surface of the medial extremity of the clavicle, to which it is attached just lateral to the lower part of the capsule. Frequently some of the lateral fibres pass upward and medially behind the rest, and give the appearance of decussating. It is from half to three-quarters of an inch (1.5-2 cm.) broad.
The articular disc (fig. 285) is a flattened disc of nearly the same size and outline as the medial articular end of the clavicle, which it fairly accurately fits. It is attached above to the upper border of the posterior edge of the clavicle ; and below to the cartilage of the first rib at its union with the sternum, where it assists in forming the socket for the clavicle. At its circumference it is connected with the articular capsule, and this connection is very strong behind, and still stronger above, where it is blended with the interclavicular ligament.
It is usually thinnest below, where it is connected with the costal cartilage. It varies in thickness in different parts, sometimes being thinner in the centre than at the circumference sometimes the reverse, and is occasionally perforated in the centre. It divides the joint into two compartments.
There are two synovial membranes (fig. 285) ; a lateral one, which is reflected from the clavicle and capsule over the lateral aspect of the disc and is looser than the medial one; the medial is reflected from the sternum over the medial side of the articular disc, costal cartilage, and capsule. Occasionally a communication takes place between them.
The arterial supply is derived from branches — (1) from the internal mammary; (2) from the superior thoracic branch of the axillary; (3) twigs of a muscular branch often arising from the subclavian artery pass over the interclavicular notch; (4) twigs of the transverse scapular (suprascapular) artery.
Relations. — In front of the joint is the sternal head of the sterno-mastoid. Behind it are the sterno-hyoid and sterno-thyreoid muscles. Still further back, on the right side, are the innominate and internal mammary arteries, and, on the left side, the left common carotid, the left subclavian, and the internal mammary arteries. Above and behind, between the sternomastoid and s terno-hyoid muscles, the anterior jugular vein passes back and laterally toward the posterior triangle.
The movements permitted at this joint are various though limited, owing to the capsular ligament being moderately tense in every position of the clavicle. Motion takes place in nearly every direction — viz., upward, downward, forward, backward, and in a circumductory manner. The upward and downward motions occur between the clavicle and the articular disc; during elevation of the arm the upper edge of the clavicle with its attached articular disc is pressed into the sternal socket, and the lower edge gUdes away from the disc; during depression of the limb, the lower edge of the clavicle presses on to the disc, while the rest of the articular surface of the clavicle inclines laterally, bringing with it to a slight degree the upper edge of the articular disc. These movements occur on an antero-posterior axis drawn through the outer compartment of the joint. The forward and backward motions take place between the articular disc and sternum, the clavicle with the disc gUding backward upon the sternum when the shoulder is brought forward, and forward when the shoulder is forced backward; these movements odcur round an axis drawn nearly vertically through the sternal socket.
The articular disc serves materially to bind the bones together, and to prevent the media and upward displacements of the clavicle. It also forms an elastic lauffer which tends to break shocks. The capsule, by being moderately tight, tends to limit movements in all directions, while the interclavicular ligament is a safeguard against upward displacement during depression of the arm. Tlie costo-clavicular ligament prevents dislocation upward during elevation of the arm, and resists displacements backward.
The scapula is connected with the clavicle by a synovial joint with its ligaments at the acromio-clavicular articulation; and also by a set of ligaments passing between the coracoid process and the clavicle. So that we have to consider —
quently contains an articular disc.
The articular capsule (figs. 287 and 290) completely surrounds the articular margins, and is composed of strong, coarse fibres arranged in parallel fasciculi, of fairly uniform thickness, which are attached to the borders as well as the surfaces of the bones. It is somewhat lax in all positions of the joint, so that the clavicle is not tightly braced to the acromion. The fibres extend three-quarters of an inch (2 cm.) along the clavicle posteriorly, but only a quarter of an inch (6 mm.) anteriorly. Superiorly, they are attached to an oblique line joining these two points, while inferiorly they reach to the ridge for the trapezoid ligament with which they blend.
At the acromion they extend half way across the upper and lower surfaces, but at the anterior and posterior limits of the joint they are attached close to the articular facet. The anterior fibres become blended with the insertion of the eoraco-acromial ligament. The fibres are strengthened above by the aponeuroses of the trapezius and deltoid muscles; and all run from the acromion to the clavicle medially and backward.
The articular disc is occasionally present, but is usually imperfect, only occupying the upper part of the joint; it may completely divide the joint into two cavities, or be perforated in the centre. It is usually thicker at the edge than in the centre, and some of the fibres of the articular capsule are blended with its edges.
entirely divided into two by the articular disc.
Relations. — Superiorly skin and fascia and the tendinous intersection between the deltoid and the trapezius. Inferiorly, the eoraco-acromial ligament and supraspinatus. Anteriorly, part of the origin of the deltoid. Posteriorly, part of the insertion of the trapezius.
Movements. — A certain amount of gliding movement occurs at this joint, but the most important movement is a rotation of the scapula whereby the glenoid cavity is turned forward and upward, or downward. As these movements occur the inferior angle of the scapula moves forward as the glenoid cavity turns upward and the superior angle recedes.
The forward movement of the inferior angle is produced mainly by the inferior fibres of the serratus anterior (magnus), aided by the inferior fibres of the trapezius, and it is by this movement that the arm is raised above the level of the shoulder forward.
and laterally from the coracoid process to the clavicle.
It is a very strong and coarsely fasciculated band of triangular shape, the apex being fixed to the medial and posterior edge of the root of the coracoid process just in front of the scapular notch, some fibres joining the transverse ligament. Its base is at the clavicle, where it widens out, to be attached to the posterior edge of the inferior surface, as well as to the coracoid tubercle. It is easily separated from the trapezoid, without being absolutely distinct. A small bursa often exists between it and the coracoid process; medially, some of the fibres of the subclavius muscle are often attached to it.
The trapezoid ligament is the anterior and lateral portion of the coracoclavicular ligament. It is a strong, flat, quadrilateral plane of closely woven fibres, the surfaces of which look upward and medially toward the clavicle, and downward and laterally over the upper surface of the coracoid process.
At the coracoid it is attached for about an inch (2.5 cm.) to a rough ridge which runs forward from the angle, along the anterior border of the process. At the clavicle it is attached to the oblique ridge which runs laterally and forward from the coracoid tubercle, reaching as far as, and blending with the inferior part of the acromio-clavicular ligament. Its anterior edge is free, and overlies the eoraco-acromial Ugament; the posterior edge is shorter than the anterior, and is in contact with the posterior and lateral portion of the conoid hgament.
Movements. — In the movements of the shoulder girdle, the scapula moves upon the lateral end of the clavicle, and the clavicle, in turn, carried by the uniting Ugaments, moves upon the sternum; so that the entire scapula moves in the arc of a circle whose centre is at the sternoclavicular joint, and whose radius is the clavicle. The scapula, in moving upon the clavicle, also moves upon the thorax forward and backward, upward and downward, and also in a rota^ tory direction upon an axis drawn at right angles to the centre of the bone. Throughout these movements the inferior angle and base of the scapula are kept in contact with the ribs by the
Long tendon of biceps
latissimus dorsi, which straps down the former, and the rhomboids and serratus anterior {magnus), which brace down the latter. The glenoid cavity could not have preserved its obUquely forward direction had there been no acromio-clavicular joint, but would have shifted round a vertical axis, and thus the shoulder would have pointed medialward when the scapula was advanced, and lateralward when it was drawn backward. By means of the acromio-clavicular joint, the scapula can be forcibly advanced upon the thorax, the glenoid cavity all the time keeping its face duly forward. Thus the muscles of the shoulder and forearm can be with advantage combined, as, for example, in giving a direct blow. The acromio-clavicular joint also permits the lower angle of the scapula to be retained in contact with the chest wall during the rising and faUing of the shoulder, the scapula turning in a hinge-like manner round the horizontal axis of the joint.
Inferior transverse.
The coraco-acromial ligament (figs. 286 and 290) is a flat, triangular band with a broad base, attached to the lateral border of the coracoid process, and a blunt apex which is fixed to the tip of the acromion. It is made up of two broad marginal bands, and a smaller and thinner intervening portion. The anterior band, which arises from the anterior portion of the coracoid process, is the stronger, and some of its marginal fibres can often be traced into the short head of the biceps, which can then make tense this edge of the ligament. The posterior band, coming from the posterior part of the coracoid process, is also strong.
The intermediate part, of variable extent, is thin and membranous, containing but few ligamentous fibres; it is often incomplete near the coracoid process, leaving a small gap (fig. 286).
The superior surface of the ligament looks upward and a little forward, and is covered by the deltoid muscle; the inferior looks downward and a little backward, and is separated from the capsule of the shoulder-joint by a bursa and the tendons of the supraspinatus and subscapularis muscles. At the coracoid process it overlies the coraco-humeral ligament. It is barely one-third of an inch (8 mm.) above the capsule of the shoulder, and in the undissected state there is scarcely a quarter of an inch (6 mm.) interval. The anterior band projects over the centre of the head of the humerus, and is continued into a tough fascia under the deltoid; the posterior band is continuous with the fascia over the supraspinatus muscle. It binds the
against it.
The superior transverse (coracoid, or suprascapular) ligament (figs. 286, 287, and 288) is a small triangular band of fibrous tissue, the surfaces of which look forward and backward; and its edges, which are thin and sharp, are turned upward and downward. It continues the superior border of the scapula, bridging over the scapular notch.
It is broader medially, where it springs from the upper border of the scapula on its dorsal surface; and narrow laterally, where it is attached to the base of the coracoid process; some of its fibres are inserted under the edge of the trapezoid ligament, and others pass upward with the conoid to reach the clavicle. The transverse scapular {suprascapular) artery passes over it, and the suprascapular nerve beneath it. Medially, some fibres of the omo-hyoid muscle arise from it.
The inferior transverse (spino-glenoid) ligament (fig. 287) reaches from the lateral border of the spine of the scapula to the margin of the glenoid cavity, and so forms a foramen under which the transverse scapular (suprascapular) vessels and suprascapular nerve gain the infraspinous fossa. It is usually a weak membranous structure with but few ligamentous fibres.
of joints, the large upper end of the humerus playing upon the shallow glenoid cavity. Like the hip, it is a ball-and-socket joint. It is retained in position much less by ligaments than by muscles, and, owing to the looseness of its capsule, as well as to all the other conditions of its construction and position, it is exceedingly liable to be displaced; on the other hand, it is sheltered from violence by the two projecting processes — the acromion and coracoid. The ligaments of the shoulder-joint are: — -
Glenoid:
The articular capsule (figs. 286, 287, and 288) is a loose sac, insufficient in itself to maintain the bones in contact. It consists of fairly distinct but not coarse fibres, closely woven together, and directed, some straight, others obliquely, between the two bones, a few circular ones being interwoven amongst them. At the scapula, it is fixed on the dorsal aspect to the prominent rough
surface around the margin of the glenoid cavity, reaching as far as the neck of the bone. Superiorly, it is attached to the root of the coracoid process; anteriorly, to the ventral surface, at a variable distance from the articular margin, often reaching half an inch (12 mm.) upon the neck of the bone, and thus allowing the formation of a pouch; it may not, however, extend for more than a quarter of an inch (6 mm.) beyond the articular margin; inferiorly, it blends with the origin of the long head of the triceps. At the humerus, the superior half is fixed to the anatomical neck, sending a prolongation downward between the two tuberosities which attenuates as it descends, and covers the transverse hmneral ligament. The lower half of the capsule descends upon the hmnerus further from the articular margin, some of the deeper fibres being reflected upward so as to be attached close to the articular edge, thus forming a kind of fibrous investment for the neck of the humerus. This ligament is more uniform in thickness than that of the hip.
Gleno-humeral bands of the capsule (figs. 288 and 289) . — There are three accessory bands, known as the superior, middle and inferior gleno-humeral bands, which project toward the interior of the joint from the fore part of the capsule and are consequently best seen when the joint is opened from behind.
The middle band reaches from the anterior margin of the glenoid cavity along the lower border of the subscapularis tendon to the lower border of the lesser tuberosity, and the inferior band from the inferior part of the glenoid cavity to the inferior part of the neck of the humerus.
The superior band, known also as the gleno -humeral ligament, runs from the edge of the glenoid cavity at the root of the coracoid process, just medial to the origin of the long tendon of the biceps, and, passing laterally and downward at an acute angle to the tendon, for which it forms a slight groove or sulcus, is fixed to a depression, the fovea capitis humeri, above the lesser tuberosity of the humerus. It is a thin, ribbon-hke band, of which the superior surface is attached to the capsule, while the inferior is free and turned toward the joint. In the foetus it is often, and in the adult occasionally, quite free from the capsule, and may be as thick as the long tendon of the biceps (fig. 289).
The tendons of the supra- and infraspinatus, teres minor, and subscapularis muscles strengthen and support the capsule, especially near their points of insertion, and can be with difficulty dissected off from it. The long head of the triceps supports and strengthens the capsule below. The capsule also receives an upward sUp from the pectoralis major. The supraspinatus often sends a shp into the capsule from its upper edge (fig. 288).
The coraco-humeral ligament (fig. 290) is a strong broad band, which is attached above to the lateral edge of the root and horizontal limb of the coracoid process nearly as far as the tip. From this origin it is directed backward along the line of the biceps tendon to blend with the capsule, and is inserted into the greater tuberosity of the humerus.
its origin there is sometimes a bursa between it and the capsule.
The glenoid ligament or lip [labrum glenoidale] (figs. 288 and 292) is a narrow rim of dense fibro-cartilage, which surrounds the edge of the glenoid socket and deepens it. It is about a quarter of an inch (6 mm.) wide above and below, but less at its sides. Its peripheral edge is inseparably welded, near the bone, with
the articular capsule. Its structure is almost entirely fibrous, with but few cartilage cells intermixed. At the upper part of the fossa the biceps tendon is prolonged into the glenoid ligament, the tendon usually dividing and sending fibres right and left into the ligament, which may wind round nearly the whole circumference of the socket. It may, however, send fibres into one side only, usually into the lateral.
The articular cartilage covering the glenoid fossa is thicker at the circumference than in the centre, thus tending to deepen the cavity. It is usually thickest at the lower part of the fossa; over the head of the humerus the cartilage is thickest at and below the centre.
The synovial membrane lines the glenoid ligament, and is then refiected over the capsule as far as its attachment to the humerus, from which it ascends as far as the edge of the articular cartilage. The tendon of the biceps receives a long tubular sheath, which is continuous with the synovial membrane, both at its attached extremity and at the bicipital groove, but is free in the rest of its extent. The synovial cavity almost always communicates with the bursa under the subscapularis, and sometimes with one under the infraspinatus muscle.
It also sends a pouch-like prolongation beneath the coracoid process when the fibrous capsule is attached wide of the margin of the glenoid fossa. A few fringes are seen near the edge of the glenoid cavity, and there is often one which runs down the medial edge of the biceps tendon, extending slightly below it and making a slight groove for the tendon to lie in.
The transverse humeral Ugament (fig. 290) is so closely connected with the capsule of the shoulder that, although it is a proper hgament of the humerus, it may well be described here. It is a strong band of fibrous tissue, which extends
between the two tuberosities, roofing in the intertubercular (bicipital) groove. It is covered by a thin expansion of the capsule. It is limited to the portion of the bone above the line of the epiphysis.
Relations. — -The following muscles are in contact with the capsule of the shoulder-joint. In front, the subscapularis; above, the supraspinatus; above and behind, the infraspinatus; behind, the teres minor; below, the long head of the triceps and the teres major. In the interval between the subscapularis and the supraspinatus the subacromial bursa is close to the capsule and occasionally its cavity communicates with the cavity of the joint.
The axillary (circumflex) nerve and posterior circumfle.x artery pass beneath the capsule in the intei'val between the long head of the triceps, the humerus, and the teres major. When the arm is abducted, the long head of the triceps and the teres major are drawn into closer rela- , tion with the capsule and help to prevent dislocation of the humerus.
The axillary vessels, the great nerves of the axilla, the short head of the biceps, and the coraco-brachialis are separated from the joint by the subscapularis, whilst the deltoid forms a kind of cap, which extends from the front to the back over the more immediate relations.
The arterial supply is derived from the transverse scapular (suprascapular), anterior and posterior circumflex, subscapular, circumflex scapular (dorsalis scapulae), and a branch from the second portion of the axiUary artery.
rotation and circumduction.
Flexion is the swinging forward, extension the swinging backward, of the humerus; abduction is the raising of the arm from, and adduction depression of the arm to, the side. In flexion and extension the head of the humerus moves upon the centre of the glenoid fossa round an
oblique line corresponding to the axis of the head and neck of the humerus, flexion being more free than extension, and in extreme flexion the scapula follows the head of the humerus, so as to keep the articular surfaces in apposition. In extension the scapula moves much less, if at all.
In abduction and adduction the scapula is fixed, and the humerus roUs up and down upon the glenoid fossa; during abduction the head descends until it projects beyond the lower edge of the glenoid cavity, and the greater tuberosity impinges against the arch of the acromion; during adduction, the head of the humerus ascends in its socket, the arm at length reaches the side, and the capsule is completely relaxed.
or hmb.
Rotation takes place round a vertical axis drawn through the extremities of the humerus from the centre of the head to the inner condyle; in rotation forward (that is, medialward) the head of the bone rolls back in the socket as the great tuberosity and shaft are turned forward; in rotation backward (that is, lateral ward) the head of the bone glides forward, and the tuberosity and shaft of the humerus are turned backward, i. e., lateralward.
Great freedom of movement is permitted at the shoulder, and this is increased by the mobility of the scapula. Restraint is scarcely exercised at all upon the movements of the shoulder by the ligaments, but chiefly by the muscles of the joint.
In abduction, the lower part of the capsule is somewhat, and in extreme abduction considerably, tightened; and in rotation medialward and lateralward, the upper part of the capsule is made tense, as is also, in the latter movement, the coraco-humeral ligament.
The movements of abduction and extension have a most decided and definite resistance offered to them other than by muscles and ligaments, for the greater tuberosity of the humerus, by striking against the acromion process and coraco-acromial ligament, stops short any further advance of the bone in these directions, and thus abduction ceases altogether as soon as the arm
of the trunk.
Further elevation of the arm beyond the right angle, in the abducted or extended position, is effected by the rotation of the scapula round its own axis by the action of the trapezius and serratus anterior muscles upon the sterno-clavioular and acromio-clavicular joints respectively.
The acromion and coracoid process, together with the coraco-acromial ligament, form an arch, which is separated by a bursa and the tendon of the supraspinatus from the capsule of the shoulder. Beneath this arch the movements of the joint take place, and against it the head and tuberosities are pressed when the weight of the trunk is supported by the arms; the greater tuberosity and the upper part of the shaft impinge upon it when abduction and extension are carried to their fullest extent.
No description of the shoulder-joint would be complete without a short notice of the peculiar relation which the biceps tendon bears to the joint. It passes over the head of the humerus a little to the medial side of its summit, and lies free within the capsule, surrounded only by a tubular process of synovial membrane. It is fiat, with the surfaces looking upward and downward, until it reaches the intertubercular (bicipital) groove, when it assumes a rounded form. It strengthens the articulation along the same course as the coraco-humeral hgament, and tends to prevent the head of the humerus from being pulled upward too'.forcibly against the inferior surface of the acromion. It also serves the purpose of a ligament by steadying the head of the humerus in various movements of the arm and forearm, and to this end is let into a groove at the upper end of the bone, from which it cannot escape on account of the abutting tuberosities and the strong transverse humeral ligament which binds it down. Further, it acts Uke the four shoulder muscles which pass over the capsule, to keep the head of the humerus against the glenoid socket; and, moreover, it resists the tendency of the pecloralis major and latissimus dorsi muscles, in certain actions when the arm is away from the side of the body, to pull the head of the humerus below the lower edge of the cavity.
The elbow [articulatio cubiti] is a complete hinge, and, unlike the knee, depends for its security and strength upon the configuration of its bones rather than on the number, strength, or arrangement of its ligaments. The bones composing it are the lower end of the humerus above, and the upper ends of the radius and ulna below; the articular surface of the humerus being received partly within the semilunar notch (great sigmoid cavity) of the ulna, and partly upon the cup-shaped area (fovea) of the radial head. The ligaments form one large and capacious capsule [capsula articularis], which, by blending with the annular ligament, and then passing on to be attached to the neck of the radius, embraces the elbow and the superior radio-ulnar joints, uniting them into one. Laterally, it is considerably strengthened by superadded fibres arising from the epicondyles of the humerus and inseparably connected with the capsule. For convenience of description it will be spoken of as consisting of four portions:- —
The anterior portion (fig. 293) is attached to the front of the humerus above the articular surface and coronoid fossa, in an inverted V-shaped manner, to two very faintly marked ridges which start from the front of the medial and lateral epicondyles, and meet a variable distance above the coronoid fossa. Below, it is fixed, just beyond the articular margin, to the front of the coronoid process and it is intimately blended with the front of the annular ligament, a few fibres passing on to the neck of the radius.
It varies in strength and thickness, being sometimes so thin as barely to cover the syriovial membrane; at others, thick and strong, and formed of coarse decussating fibres, the majority of which descend from the medial side laterally to the radius.
The posterior portion (fig. 294), thin and membranous, is attached superiorly to the humerus, in much the same inverted V-shaped way as the anterior; ascending from the medial epicondyle, along the medial side of the olecranon fossa nearly to the top; then, crossing the bottom of the fossa, it descends on the lateral side, skirting the lateral margin of the trochlear surface, and turns laterally along the posterior edge of the capitulum. Inferiorly, it is attached to a slight groove
along the superior and lateral surfaces of the olecranon, and the rough surface of the ulna just beyond the radial notch, and to the annular ligament, a few fibres passing on to the neck of the radius.
The medial portion, the ubiar collateral ligament (fig. 293), is thicker, stronger, and denser than either the anterior or posterior portions. It is triangular in form, its apex being attached to the anterior and under aspect of the medial epicondyle, and to the condyloid edge of the groove between the trochlea and the condyle. The fibres radiate downward from this attachment, the anterior passing forward to be fixed to the rough overhanging medial edge of the coronoid
process ; the middle descend less obliquely to a ridge running between the coronoid and olecranon processes, while the posterior pass obliquely backward to the medial edge of the olecranon just beyond the articular margin.
An oblique band (the oblique ligament of Sir Astley Cooper) connects the margin of the olecranon process with the margin of the coronoid process. It lies superficial to the posterior fibres of the ulnar collateral ligament. The anterior fibres are the thickest, strongest, and most pronounced.
The lateral portion, the radial collateral ligament (fig. 294), is attached above to the lower part of the lateral epicondyle, and from this the fibres radiate to their attachment into the lateral side of the annular ligament, a few fibres being prolonged to reach the neck of the radius. The anterior fibres reach further forward than the posterior do behind. It is strong and well-marked, but less so than the medial portion.
Outside the synovial membrane, but inside the capsule, are often seen some pads of fatty tissue; one is situated on the medial side at the base of the olecranon, another is seen on the lateral side projecting into the cavity between the radius and ulna; this latter, with a fold of synovial membrane opposite the front of the lateral hp of the trochlea, suggests the division of the joint into two parts — one medially for the ulna, and another laterally for the radius. There are also pads of fatty tissue at the bottom of the olecranon and coronoid fossas, and at the tip of the olecranon process.
The arterial supply is derived from each of the vessels forming the free anastomosis around the elbow, and there is also a special branch to the front and lateral side of the joint, from the brachial artery, and the arterial branch to the brachialis also feeds the front of the joint.
Relations. — In front of the joint, and in immediate relation with the capsule, are the brachiahs, the superficial and deep branches of the radial (musculo-spiral) nerve, the radial recurrent artery, and the brachio-radiahs. The brachial artery, the median nerve, and the pronator teres are separated from the capsule by the brachiahs. Directly behind the capsule are the triceps, the anconeus, and the posterior interosseous recurrent artery. On the medial side are the ulnar nerve, the superior ulnar collateral (posterior ulnar recurrent) artery, and the upper parts of the flexor carpi ulnaris and flexor digitorum subhmis. On the lateral side lie the extensor carpi radiahs longus and the upper part of the common tendon of origin of the superficial extensors of the wrist and fingers.
The movements permitted at the elbow are those of a true hinge joint, viz., flexion and extension. These movements are oblique, so that the forearm is inclined medially in flexion, and laterally in extension ; they are limited by the contact respectively of the coronoid and olecranon processes of the ulna with their corresponding fossae on the humerus, and their extent is determined by the relative proportion between the length of the processes and depth of the fossae which receive them, rather than by the tension of the ligaments, or the bulk of the soft parts over them. The anterior and posterior portions of the capsule, together with the corresponding portions of the collateral ligament, are not put on the stretch during flexion and extension; but, although they may assist in checking the velocity, and thus prevent undue force of impact, they do not control or determine the extent of these movements. The limit of extension is reached when the ulna is nearly in a straight line with the humerus; and the limit of flexion when the ulna describes an angle of from 30° to 40° with the humerus.
The obliquity of these movements is due to the lateral inclination of the upper and back part of the trochlear surface, and the greater prominence of the medial lip of the trochlea below; thus the plane of motion is directed from behind forward and medially, and carries the hand toward the middle third of the clavicle. The obliquity of the joint, the twist of the shaft of the humerus, and the backward direction of its head, all tend to bring the hand toward the midline of the body, under the immediate observation of the eye, whether for defence, employment, or nourishment. This is in striking contrast to the lower limb, where the direction of the foot diverges from the median axis of the trunk, thus preventing awkwardness in locomotion. In flexion and e.xtension, the cup-like depression of the radial head glides upon the capitulum, and the medial margin of the radial head travels in the groove between the capitulum and the trochlea. This allows the radius to rotate upon the humerus while following the ulna in all its movements. In full extension and supination, the head of the radius is barely in contact with the inferior surface of the capitulum, and projects so much backward that its posterior margin can be felt as a prominence at the back of the elbow. In full flexion the anterior edge of the radial head is received into, and checked against, the depression above the capitulum ; while in mid-flexion the cup-like depression is fairly received upon the capitulum, and in this position, the radius being more completely steadied by the humerus than in any other, pronation and supination take place most perfectly.
The bones which enter into this joint (which is often included with the elbowjoint) are, the ulna by its radial notch and the radius by the smooth vertical border or rim on its head. There is but one ligament special to the joint, viz.: —
Annular.
The annular ligament consists of bands of strong fibres, somewhat thicker than the capsule of the elbow-joint, which encircle the head of the radius, retaining it against the side of the ulna. The bulk of these fibres forms about threefourths of a circle, and they are attached to the anterior and posterior margins of the radial notch; some few are continued round below the radial notch, and form a complete ligamentous circle.
The ligament is inseparably connected along its upper edge and lateral (i. e., its nonarticular) surface with the anterior, posterior, and lateral portions of the capsule of the elbow, a few of the fibres of these portions, especially of the lateral, descending to be attached to the necli of the radius. The lower part of the articulation is covered in anteriorly, posteriorly, and laterally by a thin independent membranous layer, which passes from the lower edge of the annular ligament to the neck of the radius, strengthened on the lateral side by those fibres passing down from the capsule. They are loose enough to allow the bone to rotate upon its
radius.
The synovial membrane is the same as that of the elbow-joint, and, after lining the annular ligament, passes on to the neck of the radius, and thence up to the lower margin of the articular cartilage.
process, downward and laterally to be attached to the posterior edge of the lower end of the tuberosity of the radius and the vertical ridge running from it to the medial border of the bone.
Some of its fibres blend with the fibres of insertion of the biceps tendon; behind, it is in close contact with the supinator; below, a thin membrane passes off from it to the upper edge of the interosseous membrane; the posterior interosseous vessels pass in the space between it and the interosseous membrane; occasionally a slip is continued into the annular ligament of the superior radio-ulnar articulation (see fig. 298).
The interosseous membrane (fig. 293) is attached to the ulna at the lowest part of the ridge in front of the depression for the supinator, and along the whole length of the interosseous border as far as the inferior radio-ulnar articulation, approaching the front of the bone in the lower part of its attachment. To the radius it is attached along the interosseous border, from an inch (2.5 cm.) below the tuberosity to the ulnar notch for the lower end of the ulna.
It is strongest and broadest in the centre, where the fibres are dense and closely packed ; it is also well marked beneath the pronator quadratus, and thickens considerably at the lower end, forming a strong band of union between the two bones. Its fibres pass chiefly downward and medially, from the radius to the ulna, though some take the opposite direction; at the lower end some are transverse. On the posterior surface are one or two bands, which pass downward and laterally from the ulna to the radius, and frequently there is a strong bundle as large as the
Fig. 298. — Upper Portions of Left Ulna and Radius, to show an Occasional Slip prom THE Oblique Cohd to the Lower Part op the Annular Ligament. This condition is present in the spider monkey (Ateles), which has no external thumb but only rudimentary bones of one.
Oblique cord
oblique cord; this, which may be called the inferior oblique ligament (fig. 303), stretches from the ulna, an inch and a half above its lower extremity, downward and laterally to the ridge above and behind the ulnar notch of the radius.
At its attachment to the bones, the interosseous membrane blends with the periosteum. Its upper border is connected with the oblique cord by a thin membrane, which is pierced by the posterior interosseous vessels; and the lower border, which stretches across between the two bones just above the inferior radio-ulnar articulation, assists in completing the capsule of that joint. Its anterior surface is iii relation with the flexor digitorum profundus and flexor pollids longus in the upper three-quarters, the lower fourth being in relation with the pronator quadratus. The anterior interosseous vessels and nerve descend along the middle of the membrane, the artery being bound down to it. About an inch from the lower end it is pierced by the anterior interosseous artery. The posterior surface is in relation with the supinator, abductor pollids longus (extensor ossis metacarpi pollids), extensor pollids longus and brevis, and the extensor indids proprius; at its lower part, also with the posterior branch of the anterior interosseous artery, and the deep branch of the radial nerve (posterior interosseous).
This is, in one respect, the reverse of the superior; for the radius, instead of presenting a circular head to rotate upon the facet on the ulna, presents a concave facet which rolls round the ulna. The articulation may be said to consist of two
The articular disc (triangular fibro-cartilage) (figs. 303 and 304) assists the radius in forming an arch under which is received the first row of carpal bones. Its base is attached to the margin of the radius, separating the ulnar notch from the articular surface for the carpus, while its apex is fixed to the fossa at the base of the styloid process of the ulna. It gradually and uniformly diminishes in width from base to apex, becoming rounded where it is fixed to the ulna; it is joined by fibres of the ulnar collateral ligament of the wrist.
Fig. 299. — ^Lower Extremities op the Radius and Ulna to Show the Relation op THE Articulab Capsule OP THE Wrist Joint (In red) to the Epiphysial Lines. Note the upward extension of the membrana saccLformis.
itself to the ulna, and smooth and slightly concave below to fit over the triquetral bone. Its anterior and posterior borders are united to the anterior and posterior radio-ulnar and radiocarpal ligaments. It is the most important structure in the inferior radio-carpal articulation, as it is a very firm bond of union between the lower ends of the bones, and serves to hmit their movements upon one another more than any other structure in either the upper or lower radioulnar joints. Its structure is fibrous at the circumference, while in the centre there is a preponderance of cells. It differs from all other fibro-cartilages in entering into two distinct articulations; and separates entirely the synovial membrane of the radio-ulnar joint from that of the wrist.
The lower end of the interosseous membrane extends between the ulna and radius immediately above their points of contact. Transverse fibres between the two bones form a sort of arch above the concave articular facet of the radius, and, joining the anterior and posterior radio-ulnar ligaments, complete the articular capsule of the inferior radio-ulnar joint. The ligaments represent merely thickenings of the capsule.
cartOage from base to apex.
The posterior radio-ulnar ligament (fig. 301) is similarly attached to the posterior margin of the ulnar notch at one end, and at the other to the rough bone above the articular surface of the extremity of the ulna as far medially as the groove for the extensor carpi ulnaris, with the sheath of which it is connected, as well as into the whole length of the posterior margin of the articular disc. Both the radio-ulnar ligaments consist of thin, almost scattered, fibres.
The synovial membrane, sometimes called the membrana sacciformis, is large and loose in proportion to the size of the joint. It is not onty interposed between the radial and ulnar articular surfaces, but lines the terminal articular surface of the ulna and the upper surface of the articular disc.
The movements of the radius. — The upper end of the radius rotates upon an axis drawn through its own head and neck within the coUar formed b}' the radial notch and the annular ligament, while the lower end, retained in position by the articular disc, rolls round the head of the ulna. This rotation is called pronation, when the radius from a position nearly parallel to the ulna turns medialward so as to lie obliquely across it; and supination, when the radius turns back again, so as to uncross and lie nearly parallel with the ulna. In these movements the radius carries with it the hand, which rotates on an axis passing along the ulnar side of the hand; thus, the hand when pronated hes with its dorsum upward, as in playing the piano, whUe when supinated, the palm lies upward — the attitude of a beggar asking alms. Ward thus expresses the relations of the two extremities of the radius in pronation and supination: 'The head of the radius is so disposed in relation to the sigmoid cavitj' (ulnar notch) at the lower end that the axis of the former if prolonged falls upon the centre of the circle of which the latter is a segment;' the axis thus passes through the lower end of the ulna at a point at which the articular disc is attached, and if prolonged further, passes through the ring finger. Thus the radius describes, in rotating, a blunt-pointed cone whose apex is the centre of the radial head, and whose base is at the wrist; partial rotation of the bone being unaccompanied by anj' hinge-like or antero-posterior motion of its head, and pronation and supination occurring without disturbance to the parallelism of the bones at the superior radio-ulnar joint. Associated with this rotation in the ordinary way, there is some rotation of the humero-ulnar shaft, which causes lateral shifting of the hand from side to side; thus, with pronation there is some abduction, and with supination some adduction combined, so that the hand can keep on the same superficies in both pronation and supination. The power of supination in man is much greater than pronation, owing to the immense power and leverage obtained by the cm-ve of the radius, and bj' the attachment of the biceps tendon to the back of the tuberosity. For this reason all our screw-driving and boring tools are made to be used bj- supination movements.
In the undissected state, the amount of rotation it is possible to obtain is about 135°, so that neither the palm nor the fore part of the lower end of the radius can be turned completely in opposite directions; j-et in the hving subject this amount can be greatly increased by rotation of the humero-ulnar shaft at the shoulder-joint.
Pronation is checked in the living subject by (a) the posterior inferior radio-ulnar ligament, which is strengthened by the connection of the sheath of the extensor tendons with it; (b) the lowermost fibres of the interosseous membrane; (c) the back part of the ulnar collateral and adjacent fibres of the posterior hgament of the wrist, and (d) the meeting of the soft parts on the front of the forearm.
Supination is checked mainly (a) by the medial ulnar collateral ligaments of the wrist, but partly also by (b) the oblique cord; (c) the anterior inferior radio-ulnar hgament, and (d) the lowest fibres of the interosseous membrane.
The interosseous membrane serves, from the direction of its fibres downward and medially from the radius to the ulna, to transmit the weight of the body from the ulna to the radius in the extended position of the elbow, as in pushing forward with the arms extended, or in supporting one's own weight on the hands, the ulna being in intimate contact with the humerus, but not at all with the carpus; whOe the area of contact of the radius with the humerus is small, and that of the radius with the carpus large. Hence the weight transmitted bj' the ulna is communicated to the radius by the tightening of the interosseous membrane. Conversely, in falls upon the hand with the arm extended, the interosseous membrane acts as a sUng to break the violence of the shock, and prevents the whole force of the impact from expending itself directly upon the capitulum.
The wrist-joint is formed by the imion of the radius and articular disc above, articulating -^vith the navicular, lunate, and triquetral bones below; the ulna being excluded by the intervention of the articular disc. The radius and disc together present a smooth surface, slightly concave both from before backward, and from side to side, whilst the three bones of the carpus present a smooth,
them together.
The capsule of the wrist-joint has been usually described as four separate ligaments, and it will be convenient for the sake of a complete description to follow this method; but it must be understood that these four portions are continuous around the joint, extending from styloid process to styloid process on both its aspects.
Radial collateral.
The volar (or anterior) radio-carpal (fig. 300) is a thick strong ligament, attached superiorly to the radius immediately above the anterior margin of the terminal articular facet, to the curved ridge at the root of the styloid process of the radius, and to the anterior margin of the articular disc, blending with some fibres of the capsule of the inferior radio-ulnar joint. It passes downward and in a medial direction to be attached to both rows of carpal bones, especially the second, and to the volar intercarpal ligament.
The strongest and most oblique fibres arise from the root of the styloid process of the radius, and pass obhquely over the navicular, with which only a few fibres are connected, to be inserted into the lunate, capitate, and triquetral bones. Another set, less oblique, passes from the margin of the facet for the lUnate to be attached to the adjacent parts of the capitate, hamate, and triquetral bones. Between the two sets of fibres, small vessels pass into the joint.
The dorsal (or posterior) radio-carpal ligament (fig. 301) is attached above to the dorsal edge of the lower end of the radius, the back of the styloid process, and the posterior margin of the fibro-cartilage. It passes downward and in a medial direction to be connected with the first row of the carpal bones, chiefly with the lunate and triquetral, and the dorsal intercarpal ligament. This ligament is thin and membranous.
It is strengthened by (i) strong fibres passing from the back of the articular disc where they are blended with the posterior inferior radio-ulnar ligament, and, from the edge of the radius just behind the ulnar notch, to the triquetral bone; (ii) from the ridge and groove for the extensor pollicis longus to the back of the lunate and triquetral bones; and (iii) from the groove for the radial e.xtensors to the back of the navicular and lunate. It is in relation with, and strengthened by, the extensor tendons which pass over it.
the apex of the articular disc. Some of the fibres pass forward and laterally to the base of the pisiform bone and to the medial part of the upper border of the transverse carpal ligament, where it is attached to the pisiform bone; they form a thick, rounded fasciculus on the front of the wrist. Other fibres descend vertically to the medial side of the triquetral bone, and others again laterally to the dorsal surface of the triquetral. The tendon of the extensor carpi ulnaris is posterior to, and passes over, part of the fibres of the ligament.
The radial collateral ligament (fig. 300) consists of fibres which radiate from the fore part and tip of the styloid process of the radius. Some pass downward and medially, in front, to the navicular and adjacent edge of the capitate; some downward, a little forward and medially, to the tubercle of the navicular and ridge of the greater multangular; and others downward and laterally to the rough dorsal surface of the navicular.
The fibres of this ligament are not so long and strong, nor do they radiate so much as those of the ulnar collateral ligament. It is in relation with the radial artery, and the abductor pollicis longus {extensor ossis metacarpi pollicis) and extensor pollicis brevis, the artery separating the tendons from the ligament.
The synovial membrane is extensive, but does not usually communicate with the synovial membrane of the inferior radio-ulnar joint, being shut out by the articular disc. It is also excluded, in almost every instance, from that of the carpal joints by the interosseous ligaments between the first row of carpal bones. The styloid process of the radius is cartilage-covered medially, and forms part of the articular cavity, while that of the ulna does not.
the median and ulnar nerves.
Behind the joint are the majority of the tendons of the extensor muscles of the wrist and fingers, with their synovial sheaths, the terminal part of the anterior and posterior interosseous arteries, and the deep branch of the radial nerve (posterior interosseous). On the radial side lie the tendons of the abductor pollicis longus {extensor ossis metacarpi pollicis) and the extensor pollicis brevis. On the ulnar side the joint is subcutaneous and it is crossed by the dorsal cutaneous branch of the ulnar nerve.
Movements. — The wrist is a condyloid joint, the carpus forming the condyle. It allows of movements upon a transverse axis, i. e., flexion and extension; and around an antero-posterior axis, i. e., abduction and adduction; together with a combination of these in quick succes-
sion — oiroumduction. Lacking only rotation on a vertical axis, it thus possesses most of the movements of a ball-and-socket joint, without the weakness and liability to dislocation which are peculiar to these joints. This deficiency of rotation is compensated for by the movements of the radius at the radio-ulnar joints, viz., supination and pronation. Its strength depends chiefly upon the number of tendons which pass over it, and the close connection which exists between the fibrous tissue of their sheaths and the capsule of the wrist; also upon the proximity of the medio-carpal and carpo-metacarpal joints, which permits shocks and jars to be shared and distributed between them; another source of strength is the absence of any long bone on the distal side of the joint. In flexion and extension the carpus rolls backward and forward, respectively, beneath the arch formed by the radius and articular disc; flexion being limited by the dorsal ligament and dorsal portions of the collateral; extension by the volar, and volar portions of the collateral ligaments. In adduction and abduction the carpal bones ghde from the ulnar to the radial side and from the radial to the ulnar side, respectively. Abduction is more limited than adduction, and is checked by the ulnar collateral hgament and by contact of the styloid process of the radius with the greater multangular; adduction is checked by the radial collateral ligament alone. One reason for adduction being more free than abduction is that the ulna does
not reach so low down as the radius, and the yielding articular disc allows of greater movement upward of the ulnar end of the carpus. In circumduction the hand moves so as to describe a cone, the apex of which is at the wrist. These movements are made more easy and extensive by the slight gliding of the carpal bones upon one another, and the comparatively free motion at the medio-carpal joint. The oblique direction of the fibres of the collateral hgaments prevents any rotation at the radio-carpal joint, while it permits considerable freedom of abduction and adduction.
Muscles which act upon the radio-carpal joint. — Flexors. — The flexors of the carpus and the long flexors of the fingers and the thumb, and the pahnaris longus. Extensors. — The extensors of the carpus and fingers. Abductors. — Extensor carpi radialis longus, the abductor pollicis longus (extensor ossis metacarpi poUicis. Adductors. — Flexor carpi ulnaris, extensor carpi ulnaris.
7. THE CARPAL JOINTS
The joints of the carpus may be subdivided into — • (a) The joints of the first row. (6) The joints of the second row. (c) The medio-carpal, or junction of the two rows with each other.
The two dorsal intercarpal ligaments extend transversely between the bones, and connect the navicular with the lunate, and the lunate with the triquetral. Their posterior siu-faces are in contact with the posterior ligament of the -nTist.
The two volar intercarpal ligaments extend nearly transversely between the bones connecting the navicular with the lunate, and the lunate with the triquetral. They are Wronger than the dorsal ligaments, and are placed beneath the anterior ligament of the wrist.
and being connected with the dorsal and volar ligaments. They are narrow fibro-cartilages which extend between small portions only of the osseous surfaces. They help to form the convex carpal surface of the radio-carpal joint, and are somewhat wedge-shaped, their bases being toward the wrist, and their thin edges between the adjacent articular surfaces of the bones.
surfaces.
It is lined by a separate synovial membrane. Two strong rounded or flattened bands pass downward from the pisiform, one to the process of the hamate [Ug. pisohamatum], and the other [Ug. pisometacarpeum] to the bases of the third to fifth metacarpals; these are regarded as prolongations of the tendon of the flexor carpi ulnaris, and the pisiform bone may be looked upon in the light of a sesamoid bone developed in that tendon.
Three interosseous ligaments connect the bones of the lower row of the carpus together. Two are connected with the capitate, one uniting it with the hamate (fig. 304) and the other binding it to the lesser multangular. The third Mgament joins the greater and lesser multangular.
The inferior surfaces of the bones of the first row are adapted to the superior articular surfaces of the bones of the second row. The line of this articulation is concavo-convex from side to side, and is sometimes described as having the course of a Roman S placed horizontally, co , a resemblance by no means strained, (i) The lateral part of the first row consists of the navicular alone; it is convex, and bears the greater and lesser multangulars. (ii) Then follows a transversely elongated socket formed by the medial part of the navicular, the lunate, and triquetral, into which are received — (a) the head of the capitate, which articulates with the navicular and lunate; (6) the upper and lateral angle of the hamate, which articulates with the navicular; and (c) the upper convex portion of the medial surface of the hamate, which articulates with the lateral and concave portion of the inferior surface of the triquetral, (iii) The medial part of the inferior surface of the triquetral bone is convex, and turned a little backward to fit into the lower portion of the medial surface of the hamate, which is a little concave and turned forward to receive it. The central part, which forms a socket for the capitate and hamate, has somewhat the character of a condyloid joint, the capitate and hamate being the condyle, to fit into the cavity formed by the navicular, lunate, and triquetral; the other portions are typically arthrodial. The ligaments are: — (1) radiate or anterior medio-carpal; (2) posterior medio-carpal; (3) transverse dorsal.
The radiate, anterior or volar medio-carpal is a ligament of considerable strength, consisting mostly of fibres which radiate from the capitate to the navicular, lunate, and triquetral; some few fibres connect the greater and lesser multangular with the navicular, and others pass between the hamate and triquetral. It is covered over and thickened by fibrous tissue derived from the sheaths of the flexor tendons and the fibres of origin of the small muscles of the thumb and httle finger.
The posterior or dorsal medio-carpal ligament, consists of fibres passing obliquely from the bones of the first row to those of the second. It is stronger on the ulnar side than on the radial, but is not so strong as the volar ligament.
The transverse dorsal ligament (fig. 303) is an additional band, well marked and often of considerable strength, which passes across the head of the capitate from the navicular to the triquetral bone; besides binding down the head of the capitate, it serves to fix the upper and lateral angle of the hamate in the socket formed by the first row.
The dorsal ligaments, like the volar, are strengthened by a quantity of fibrous tissue belonging to the sheaths of the extensor tendons, and by an extension of some of the fibres of the capsule of the wrist. There are no proper collateral medio-carpal hgaments; they are but prolongations of the collateral ligaments of the wrist.
The synovial membrane (fig. 304) of the carpus is common to all the joints of the carpus, and extends to the bases of the four medial metacarpal bones. Thus, besides hning the inter- or medio-carpal joint, it sends two processes upward between the three bones of the first row, and thi'ee downward between the contiguous surfaces of the lesser and greater multangular, the lesser multangular and capitate, and capitate and hamate. From these latter, prolongations extend to the four medial carpo-metacarpal joints and the three intermetacarpal joints.
The arterial supply is derived from — (a) the volar and dorsal carpal rami of the radial and ulnar arteries; (b) the carpal branch of the volar interosseous; (c) the recurrent branches from the deep palmar arch. The terminal twigs of the volar and dorsal interosseous arteries supply the joint on its dorsal aspect.
instead of in front.
The movements of the carpal articulations between bones of the same row are very hmited and consist only of slight gliding upon one another; but, slight as they are, they give elasticity to the carpus to break the jars and shocks which result from blows or falls upon the hand.
The movements of one row of bones upon the other at the medio-carpal joint are more extensive, especially in the direction of flexion and extension, so that the hand enjoys a greater range of these movements than is permitted at the wrist-joint alone. At the wrist, extension is more free than flexion; but this is balanced by the greater freedom of flexion than of extension at the medio-carpal joint, and by flexion at the carpo-metacarpal joint, so that on the whole- the range of flexion of the hand is greater than that of extension.
pha angeal and interphalangeal
A slight amount of side to side motion accompanied by a limited degree of rotation also takes place; this rotation consists in the head of the capitate and the superior and lateral angle of the hamate bone rotating in the socket formed by the three bones of the upper row, and in^a gliding forward and backward of the greater and lesser multangular upon the navicular.
facets render this joint very secure.
Bearing in mind the mobility of this medio-carpal joint and of the carpo-metacarpal, we see at once the reason for the radial and ulnar flexors and extensors of the carpus being prolonged down to their insertion into the base of the metacarpus, for they produce the combined effect of motion at each of the three transverse articulations: — (1) at the wrist; (2) at the medio-carpal; (3) at the carpo-metacarpal joints.
Muscles which act upon the mid-carpal joint. — The muscles which act upon this joint are the same as those which act upon the radio-carpal joint, except the flexor carpi ulnaris, which is inserted into the pisiform bone.
The inferior surfaces of the bones of the second row of the carpus present a composite surface for the four medial metacarpal bones ; the greater multangular presents in addition a distinct and separate saddle-shaped surface for the base of the metacarpal bone of the thumb.
These joints exist between the greater and lesser multangular, capitate, and hamate bones above, and the four medial metacarpal bones below. The ligaments which unite them are, dorsal, volar, and interosseous.
The dorsal ligaments (fig. 303). — Three dorsal ligaments pass to the second metacarpal bone: one from each of the carpal bones with which it articulates, viz., the greater and lesser multangular, and capitate. Two dorsal bands pass from the capitate to the third metacarpal bone. Two dorsal bands pass to the fourth bone: viz., one from the hamate, and another from the capitate; the latter is sometimes wanting. The fifth bone has only one band passing to it from the hamate.
The volar ligaments (fig. 300). — One strong band passes from the second metacarpal bone to the greater multangular medial to the ridge for the transverse carpal ligament; it is covered by the sheath of the flexor carpi radialis.
One ligament connects the fourth bone to the hamate.
One ligament connects the fifth bone to the hamate, the fibres extending medially, and connecting the dorsal and volar ligaments. The ligament to the fifth bone is strengthened in front by the prolonged fibres of the flexor carpi ulnaris and the strong medial sUp of the ligament of the third metacarpal bone; and posteriorly, by the tendon of the extensor carpi ulnaris.
The interosseous ligament (fig. 304) is Hmited to one part of the articulation, and consists of short fibres connecting the contiguous angles of the hamate and capitate with the third and fourth metacarpal bones toward their volar aspect. There is, however, a thick strong ligament connecting the edge of the greater multangular with the lateral border of the base of the second metacarpal bone; it helps to separate the carpo-metacarpal joint of the thumb from the common carpo-metacarpal joint, and to close in the radial side of the latter joint.
The synovial membrane is a continuation of the medio-carpal joint; occasionally there is a separate membrane between the hamate and fourth and fifth metacarpal bones (fig. 304) ; while that between the fourth and capitate is lined by the synovial sac of the common joint.
Relations. — In front of the four medial carpo-metacarpal joints are the flexors of the fingers with their synovial sheath. The flexor carpi radialis crossing in front of the lateral part of the joint and the fibres of the oblique adductor poUicis which spring from the capitate and lesser multangular are also anterior relations. Behind the joints are the extensors of the wrist and fingers with their synovial sheaths and the dorsal metacarpal arteries. At the lateral border of the joints between the index and lesser multangular hes the radial artery.
The movements permitted at these joints, though slight, serve to increase those of the medio-carpal and wrist-joints. The joint between the fifth metacarpal and the hamate bones approaches somewhat in shape and mobihty the first carpo-metacarpal joint; it has a greater range of flexion and extension, but its side to side movement is nearly as limited as that of the three other metacarpal bones; the process of the hamate bone hrnits its flexion. Motion toward the ulnar side is checked by the strong palmar band which unites the base of the fifth metacarpal to the base of the third, and the strong transverse ligament at the head of the bones. The mobility of the second, third, and fourth metacarpal bones is very limited, and consists almost entirely of a slight gliding upon the carpal bones, i. e., flexion and extension; that of the third and fourth bones is extremely slight, as there is no long flexor attached to either; but,
inserted.
Abduction, or movement toward the radial side, is prevented by the impaction of the second bone against the greater multangular; a little adduction is permitted, and is favoured by the slope given to the hamate and fifth metacarpal bones.
The bones entering into this joint are the base of the first metacarpal and the greater multangular. The first metacarpal bone diverges from the other four, contrasting very strongly with the position of the great toe. It is due to this divergence that the thumb is able to be opposed to each and all the fingers. The ligament which unites the bones is the
The articular capsule (figs. 300 and 301) consists of fibres which pass from the margin of the articular facet on the greater multangular, to the margin of the articular facet at the base of the first metacarpal bone.
The fibres are stronger on the dorsal than on the palmar aspect. They are not tense enough to hold the bones in close contact, so that while they restrict they do not prevent motion in any direction. The medial fibres are stronger than the lateral.
The nerves are supplied by the branches of the median to the thumb.
Relations. — Behind are the long and short extensor tendons of the thumb, and behind and laterally the tendon of the abductor pollicis longus (extensor ossis metacarpi pollicis). The tendon of the flexor pollicis longus is in front and fibres of the flexor pollicis brevis and opponens pollicis muscles are also anterior relations. To the medial side is the radial artery as it passes forward into the palm of the hand.
The movements of this joint are regulated by the shape of the articular surfaces, rather than by the ligaments, and consist of flexion, extension, abduction, adduction, and circumduction, but not rotation. In flexion and extension the metacarpal bone slides to and fro upon the multangular; in abduction and adduction it slides from side to side or, more correctly, revolves upon the antero-posterior axis of the joint. The power of opposing the thumb to any of the fingers is due to the forward and medial obliquity of its flexion movement, which is by far its most extensive motion. Abduction is very free, while adduction is limited on account of the proximity of the second metacarpal bone. The movement of the greater multangular upon the rest of the carpus somewhat increases the range of all the movements of the thumb.
Muscles which act upon the carpo-metacarpal joint of the thumb. — Flexors. — Flexor pollicis brevis, flexor pollicis longus, opponens pollicis. Extensors. — Extensores pollicis brevis and longus and abductor pollicis longus. Ahduclors. — Abductores pollicis longus and brevis. Adductors. — The transverse and oblique adductor pollicis, opponens, fii'st dorsal interosseous. Muscles "producing opposition. — Opponens, flexor brevis, oblique adductor.
The metacarpal of the thumb is not connected with any other metacarpal bone. The second, third, fourth, and fifth metacarpal bones are in actual contact at their bases, and are held firmly together by the following ligaments (in addition to the articular capsule) : —
The Union of the Heads of the Metacarpal Bones
The distal extremities of these bones are connected together on their palmar aspects by what is called the transverse ligament [lig. capitulorum]. This consists of three short bands of fibrous tissue, which unite the second and third, third and fourth, and the fourth and fifth bones. They are rather more than 6 mm. (J in.) deep, and rather less in width, and limit the distance to which the metacarpal bones can be separated. They are continuous above with the fascia covering the interosseous muscles; below, they are connected with the subcutaneous tissue of the web of the hand. They are on a level with the front surface of the bones, and are blended on either side with the edges of the glenoid hgament in front, with the lateral Ligaments
In these joints the cup-shaped extremity of the base of the first phalanx fits on to the rounded head of the metacarpal bone, and is united by the following ligaments (in addition to the articular capsule) : —
Volar accessory.
The volar accessory (or glenoid) ligament (fig. 305) is a fibro-cartilaginous plate which seems more intended to increase the depth of the phalangeal articular facet in front, than to unite the two bones. It is much more firmly attached to the margin of the phalanx than to the metacarpal bone, being only loosely connected with the palmar surface of the latter by some loose areolar tissue which covers in the synovial membrane, here prolonged some little distance upon the surface of the bone. At the sides, it is connected with the collateral ligaments and the
moid bone sometimes exists at the medial border of the joint of the little finger.
The collateral ligaments (304 and 305) are strong and firmly connect the bones with one another; each is attached above to the corresponding tubercle, and to a depression in front of the tubercle, of the metacarpal bone. From this point the fibres spread widely as they descend on either side of the base of the phalanx; the anterior fibres are connected with the glenoid ligament; the posterior blend with the tendinous expansion at the back of the joint.
to the interosseous muscles.
Relations. — I. The metacarpo-phalangeal joints of the middle three digits. In front, the tendons of the flexor profundus and flexor subhmis digitorum. On the radial side, a lumbrical, an interosseous muscle, and digital nerves and vessels; on the ulnar side, an interosseous muscle and digital vessels and nerves. Behind, the common extensor tendon and in the case of the index digit the tendon of the extensor indicis.
II. The metacarpo-phalangeal joint of the little finger. In front, the flexor quinti digiti brevis and the tendons of the flexor profundus and subhmis digitorum muscle which go to this digit. Behind, the extensor digiti quinti to a slip of the extensor digitorum communis sometimes. On the radial side, a lumbrical, the third palmar interosseous muscle, digital vessels and nerves. On the ulnar side, digital vessels and nerves.
The movements permitted at these joints are flexion, extension, abduction, adduction, and circumduction. Flexion is the most free of all and may be continued until the phak nx is at a right angle with the metacarpal bone. It is on this account that the articular surface of the head of the bone is prolonged so much further on the palmar aspect, and that the synovial membrane is here so loose and ample. Extension is the most limited of the movements, and can only be carried to a little beyond the straight line. Abduction and adduction are fairlj' free, but not so free as flexion. Flexion is associated with adduction, and extension with abduction. This may be proved by opening the hand, when the fingers involuntarily separate as they extend, while in closing the fist they come together again. The free abduction, adduction, and circumduction which are permitted at these joints are due to the fact that the long axes of the articular facets are at right angles to one another.
Muscles acting on the middle three digits. — Flexors. — Flexor digitorum profundus, flexor digitorum sublimis. Extensors. — Extensor digitorum communis and on the index digit the extensor indicis. Abductors. — Dorsal interossei. Adductors. — Volar interossei.
Muscles acting on the metacarpo-phalangeal joint of the little finger. — Flexors. — Flexor quinti digiti brevis, flexor digitorum sublimis, flexor digitorum profundus. Extensors. — Extensor digitorum communis, extensor quinti digiti. Abductor. — Abductor quinti digiti. Adductor. — Third volar interosseous.
The head of the metacarpal bone of the thumb differs considerably from the corresponding ends of the metacarpal bones of the fingers. It is less convex, wider from side to side, the palmar edge of the articular surface is raised and irregular, and here on either side of the median line are the two facets for the sesamoid bones. The base of the first phalanx of the thumb, too, is more like the base of the second phalanx of one of the other fingers. The ligaments are : —
The collateral ligaments are short, strong bands of fibres, which radiate from depressions on either side of the head of the metacarpal bone to the base of the first phalan.x and sesamoid bones. As they descend they pass a little forward, so that the gi'eater number are inserted in" front of the centre of motion.
lateral Ugament to the other, completing the articular capsule and protecting the synovial sac.
The sesamoid bones are two in number, situated on either side of the middle fine, and connected together by strong transverse fibres which form the floor of the groove for the long flexor tendon; they are connected with the base of the phalanx and head of the metacarpal bone by strong fibres. Anteriorly they give attachment to the short muscles of the thumb, and posteriorly are smooth for the purpose of gliding over the facets. The collateral ligaments are partly inserted into their sides.
The arteries and nerves come from the digital branches of the thumb.
Relations. — Of the metacarpo-phalangeal joint of the thumb: In front and externally abductor poUicis brevis and superficial head of flexor poUicis brevis. In front and medially oblique and transverse adductors and deep head of flexor poUicis brevis. Directly in front flexor pollicis longus and terminal branches of first volar metacarpal artery. Behind, extensor pollicis brevis and longus tendons. On either side, the dorsal digital vessels and the digital nerves.
The movements are chiefly flexion and extension, very little side to side movement being permitted, and that only when the joint is slightly bent. Thus this joint more nearly approaches the simple hinge character than the corresponding articulations of the fingers. The thumb gets its freedom of motion at the carpo-metacarpal joint; the fingers get theirs at the metacarpo-phalangeal, but they are not endowed with so much freedom as the thumb enjoys.
Accessory volar. Collateral.
The accessory volar (or glenoid) ligament (fig. 305), sometimes called the sesamoid body, is very firmly connected with the base of the distal bone, and loosely, by means of fibro-areolar tissue, with the head of the proximal one. It blends with the collateral ligaments at the sides, and over it pass the flexor tendons. Occasionally a sesamoid bone is developed in the cartilage of the interphalangeal joint of the thumb.
The collateral ligaments (figs. 304 and 305) are strong bands which are attached to the rough depressions on the sides of the upper phalanx, and to the projecting margins of the lower phalanx of each joint. They are tense in every position, and entirely prevent any side to side motion; they are connected posteriorly with the expansion of the extensor tendon.
Dorsally (fig. 305) the joint is covered in by the deep surface of the extensor tendon, and a little fibro-areolar tissue extends from the tendon, and thickens the posterior portion of the synovial sac, completing the articular capsule.
digital vessels and nerves.
The movements are limited to flexion and extension. Flexion is more free, and can be continued till one bone is at a right angle to the other, and is most free at the junction of the first and second bones; the second phalanx can be flexed on the first through 110° to 115° when the latter is not flexed. The greater freedom of flexion is due to the greater extent of the articular surface in front of the heads of the proximal bones, and to the direction of the flbres of the collateral hgaments, which pass a little forward to their insertion into the distal bone.
The hip is the most typical example of a ball-and-socket joint in the body, the round liead of the femur being received into the cup-shaped cavity of the acetabulum. Both articular surfaces are coated with cartilage, that covering the head of the femur being thicker above where it has to bear the weight of the body, and thinning out to a mere edge below; the pit for the ligamentum teres is the only part uncoated, but the cartilage is somewhat heaped up around its margin. Covering the acetabulum, the cartilage is horseshoe-shaped, and thicker above than below, being deficient over the depression at the bottom of the acetabulum,
Transverse. . Glenoid lip.
The articular capsule is one of the strongest ligaments in the body. It is large and somewhat loose, so that in every position of the body some portion of it is relaxed. At the pelvis it is attached, superiorly, to the base of the anterior inferior iliac spine; curving backward, it becomes blended with the deep surface of the reflected tendon of the rectus Jemoris; posteriorly, it is attached a few millimetres from the acetabular rim ; and below, to the upper edge of the groove between the acetabulum and tuberosity of the ischium. Thus it reaches the
transverse ligament, being firmly blended with its outer surface, and frequently sends fibres beyond the notch to blend with the obturator membrane. Anteriorly it is attached to the pubis near the obturator notch, to the ilio-pectineal eminence and thence backward to the base of the inferior iliac spine.
A thin strong stratum is given off from its superficial aspect behind; this extends beneath the gluteus minimus and small rotators, to be attached above to the dorsum of the ihum higher than the reflected tendon of the rectus, and posteriorly to the ilium and ischium nearly as far as the sciatic notch. As this expansion passes over the long tendon of the rectus, the tendon may be described as being in part contained within the substance of the capsule.
At the femur, the capsule is fixed to the anterior portion of the upper border of the great trochanter and to the cervical tubercle. Thence it runs down, the intertrochanteric line as far as the medial border of the femur, where it is on a level with the lower part of the lesser trochanter. It then runs upward and backward along an oblique line about 1.6 cm. (f in.) in front of the lesser trochanter, and continues its ascent along the back of the neck nearly parallel to the intertrochanteric crest, and from 12 to 16 mm. (| to f in.) above it; finally, it passes along the medial side of the trochanteric fossa to reach the anterior superior angle of the great trochanter.
On laying open the capsule, some of the deeper fibres are seen reflected upward along the neck of the femur, to be attached much nearer the head: these are the retinacula. One corresponds to the upper, and another to the lower, part of the intertrochanteric line; a third is seen at the upper and back part of the neck. They form flat bands,which lie on the femoral neck.
Superadded to the capsule, and considerably strengthening it, are three auxiliary bands, whose fibres are intimately blended with, and in fact form part of, the capsule, viz., the ilio-femoral, ischio-capsular, and pubo-capsular ligaments.
The ilio-femoral ligament (fig. 306) is the longest, widest, and strongest of the bands. It is of triangular shape, with the apex attached above to a curved line on the iUum immediately below and behind the anterior inferior spine, and its base below to the anterior edge of the greater trochanter and to the spiral line as far as the medial border of the shaft. The highest or most lateral fibres are coarse, almost straight, and shorter than the rest; the most medial fibres are also thick and strong, but obhque. This varying obliquity of the fibres, and their accumulation at the borders, explain why this band has been described as the Y-shaped ligament; but it
circumflex artery.
The ischio-capsular ligament (fig. 308) is formed of very strong fibres attached all along the upper border of the groove for the external obturator, and to the ischial margin of the acetabulum above the groove. The highest of these incline a little upward as they pass laterally to be fixed to the greater trochanter in front of the insertion of the piriformis tendon, while the other fibres curve more and more upward as they pass laterally to their insertion at the inner side of the trochanteric fossa, blending with the insertion of the external rotator tendons. When the joint is in flexion, these fibres pass in nearly straight lines to their femoral attachment, and spread out uniformly over the head of the femur; but in extension they wind over the back of the femur in a zonular manner [zona orbicularis], embracing the posterior aspect of the neck of the femur.
The pubo-capsular (pectineo-femoral) band (fig. 306) is a distinct but narrow set of fibres which are individually less marked than the fibres of the other two bands; they are fixed above to the obturator crest and to the anterior border of the iUo-pectineal eminence, reaching as far down as the pubic end of the acetabular notch. Below, they reach the neck of the femur, and are fixed above and behind the lowermost fibres of the iho-femoral band, with which they blend.
In thickness and strength the capsule varies greatly; thus, if two lines be drawn, one from the anterior inferior spine to the medial border of the femur near the lesser trochanter, and the other from the anterior part of the groove for the
of capsule
external obturator to the trochanteric fossa, all the ligament between these lines on the lateral and upper aspects of the joint is very thick and strong, while that below and to the medial side, except at the narrow pubo-capsular ligament, is
thin and weak, so that the head of the bone can be seen through it. The capsule is thickest in the course of the iho-femoral ligament, toward the lateral part of which it measures over 6 mm. (J in.). Between the ilio-femoral and ischio-capsular ligaments the capsule is very strong, and with it here, near the acetabulum, is incorporated the reflected tendon of the rectus, and here also a triangular band of fibres runs downward and forward to be attached by a narrow insertion to the ridge on the front border of the greater trochanter near the gluteus minimus (the ilio-trochanteric band) (fig. 308).
The capsule is strengthened also at this point by a strong band from the under surface of the gluteus minimus, and by the tendino-trochanteric band which passes down from the reflected tendon of the rectus to the vastus lateralis (externus) (fig. 306). This is closely blended with the capsule near the lateral edge of the ilio-femoral Ugament.
The thinnest part of the capsule is between the pubo-capsular and ilio-femoral ligaments; this is sometimes perforated, allowing the bursa under the psoas to communicate with the joint. The capsule is also very thin at its attachment to the back of the femoral neck, and again opposite the acetabular notch.
The ligamentum teres (figs. 309 and 310) is an interarticular flat band which extends from the acetabular fossa to the head of the femur, and is usually about 3.7 cm. (1| in.) long. It has two bony attachments, one on either side of the acetabular notch immediately below the articular cartilage, while intermediate fibres spring from the lower surface of the transverse ligament. The ischial portion is the stronger, and has several of its fibres arising outside the cavity, below and in connection with the origin of the transverse ligament, where it is also continuous with the capsule and periosteum of the ischium. At the femur it is fixed to the front part of the depression on the head, and to the cartilage round the margin of the depression.
It is covered by a prolongation of synovial membrane, which also covers the cushion of fat in the recess of the acetabulum; the portion of the membrane reflected over the fatty tissue does not cling closely to the round hgament, but forms a triangular fold, the apex of which is at the femur.
The transverse ligament (fig. 311) passes across the acetabular notch and converts it into a foramen; it supports part of the glenoid fibro-cartilage, and is connected with the ligamentum teres and the capsule. It is composed of decussating fibres, which arise from the margin of the acetabulum on either side of the notch, those coming from the pubis being more superficial, and passing to form
side the acetabulum
varies in strength and thickness, but is stronger at its iliac and ischial portions than elsewhere. Its base is broad and fixed to the bony rim as well as to the articular cartilage of the acetabulum on the inner, and the periosteum on the outer, side of it, and blends inseparably with the transverse ligament which supports it over the acetabular notch.
Its free margin is thin; on section it is somewhat lunated, having its outer surface convex and its articular face concave and very smooth in adaptation to the head of the bone, which it tightly embraces a little beyond its greatest circumference. It somewhat contracts the aperture of the acetabulum, and retains the head of the femur within its grasp after division of the muscles and capsular hgament. It is covered on both aspects by synovial membrane.
The synovial membrane lines the capsule and both surfaces of the glenoid lip, and passes over the border of the acetabulum to reach and cover the fatty cushion it contains. The part covering the fatty cushion is unusually thick, and is attached round the edges of the rough bony surface on which the cushion rests. The membrane is loosely reflected off this on to the ligamentum teres, along which it is prolonged to the head of the femur; thus the fibres of the round ligament are shut out from the joint cavity. From the capsule the synovial membrane is also reflected below on to the neck of the femur, whence it passes over the retinacula to the margin of the articular cartilage. A fold of synovial membrane on the under aspect of the neck often conveys to the head of the femur a branch of an artery — generally a branch of the medial circumflex.
The arterial supply comes from — (a) the transverse branches of the medial and lateral circumflex arteries; (6) the lateral branch of the obturator sends a branch through the acetabular notch beneath the transverse ligament, which ramifies in the fat at the bottom of the acetabulum, and travels down the round ligament to the head of the femur; (c) the inferior branch of the deep division of the superior gluteal; and (d) the inferior gluteal (sciatic) arteries. The branch from the obturator to the ligamentum teres is sometimes very large when the branch from the medial circumflex does not also supply the hgament.
of the articular capsule: these anastomose freely beneath the capsule around the outer aspect of the acetabulum, and supply some branches to enter the bone, and others which enter the substance of the glenoid lip. There is quite an arterial crescent upon the posterior and posterosuperior portions of the acetabulum; but no vessels are to be seen on the inner aspect of the glenoid lip.
The nerve-supply comes from — (a) femoral (anterior crural), (6) anterior division of the obtm-ator, (c) the accessory obturator, and (d) the sacral plexus, by a twig from the nerve to the quadratus femoris, or from the upper part of the great sciatic, or from the lower part of the sacral plexus.
Relations. — In front and in contact with the capsule are the psoas bursa, the tendinous part of the psoas magnus, and the Uiacus. StiU more anteriorly and not in contact are the femoral artery, the femoral (anterior crural) nerve, the rectus femoris, the sartorius, and the tensor fasciae latse.
minimus and medius.
Behind and in close relation with the capsule are the obturator externus, the gemeUi and obturator internus, and the piriformis. More superficially he the quadratus femoris, the sciatic nerves, and the gluteus maximus.
relation with the capsule.
The movements. — The hip-joint, like the shoulder, is a ball-and-socket joint, but with a much more complete socket and a corresponding limitation of movement. Each variety of movement is permitted, viz., flexion, extension, abduction, adduction, circumduction, and rotation; and any two or more of these movements not being antagonistic can be combined, i. e., flexion or extension associated with abduction or adduction can be combined with rotation in or out.
It results from the obliquity of tne neck of the femur that the movements of the head in the acetabulum are always more or less of a rotatory character. This is more especially the case during flexion and extension, and two results follow from it. First, the bearing surfaces of the femur and acetabulum preserve their apposition to each other, so that the amount of articular surface of the head in the acetabulum does not sensibly diminish pari passu with the transit of the joint from the extended to the flexed position, as would necessarily be the case if the movement of the femoral head, like that of the thigh itself, was simply angular, instead of rotatory and angular. Secondly, as rotation of the head can continue until the ligaments are tight without being checked by contact of the neck of the thigh bone with the rim of the acetabulum, flexion of the thigh so far as the joint is concerned is practically unlimited. Flexion is the most important, most frequent, and most extensive movement, and in the dissected limb, before the ligaments are disturbed, can be carried to 160°, and is then checked by the lower fibres of the ischio-capsular ligament. In the living subject simple flexion can continue until checked by the contact of the soft parts at the groin, if the knee be bent; if the knee be straight, flexion of the hip is checked in most persons by the hamstring muscles at nearly a right angle. This is very evident on trying to touch the ground with the fingers without bending the knees, the chief strain being felt at the popliteal space. This is due to the shortness of the] hamstrings. Extension is limited by the ilio-femoral ligament.
Abduction and lateral rotation can be performed freely in every position of flexion and extension — abduction being limited by the pubo-capsular hgament; lateral rotation by the ilio-femoral Ugament, especially its medial portion, during extension; but by the lateral portion, as well as by the ligamentum teres, during flexion.
Adduction is very limited in the extended thigh on account of the contact with the opposite limb. In the slightly flexed position adduction is more free than in extension, and is then limited by the lateral fibres of the ilio-femoral band and the superior portion of the capsule. In flexion the range is still greater, and limited by the ischio-capsular hgament, the hgamentum teres being also rendered nearly tight. Medial rotation in the extended position is limited by the lower fibres of the ilio-femoral ligament; and in flexion by the ischio-capsular ligament and the portion of the capsule between it and the ilio-femoral band.
The ilio-femoral band also prevents the tendency of the trunk to roU backward on the thigh bones in the erect posture, and so does away with the necessity for muscular power for this purpose; it is put on stretch in the stand-at-ease position.
The ligamentum teres is of little use in resisting violence or in imparting strength to the joint. It assists in checking lateral rotation, and adduction during flexion. A ligament can only be of use when it is tight, and it was found by trephining the bottom of the acetabulum, removing the fat, and threading a piece of whipcord round the ligament, that the ligament was slack in simple flexion, and very loose in complete extension, but that its most slack condition was in abduction. It is tightest in flexion combined with adduction and lateral rotation and almost as tight in flexion with lateral rotation alone, and in flexion with adduction alone (flgs. 313-315).
Extensors. — The gluteus maximus, the posterior fibres of the glutei medius and miQimus, the biceps, the semitendinosus, the semimembranosus, and the ischial fibres of the adductor magnus; also (slightly) the piriformis, obturator internusand gemelli. Abductors. — Gluteus maximus (upper fibres), tensor fasciae latae, gluteus medius, gluteus minimus, and, when the joint is flexed, the pii-iformis, obturator internus, the gemelli, and the sartorius also become abductors. Adductors. — Adduotores magnus, longus, brevis, and minimus, semitendinosus, biceps^ the gracilis, the peotineus, the quadratus femoris, and the lower fibres of the gluteus maxunus. Medial rotators. — Psoas (slightly), adductor magnus, semimembranosus, the anterior fibres of the gluteus medius and minimus, and the tensor fascise latae. Lateral rotators. — Gluteus maximus, posterior fibres of gluteus medius and minimus, the adductors, obturator extemus, quadratus femoris, obturator internus, the gemelli, and the piriformis when the joint is extended.
The knee is the largest joint in the body. It is rightly described as a ginglymoid joint, but there is also an arthrodial element; for, in addition to flexion and extension, there is a sliding backward and forward of the tibia upon the femoral condyles, as well as slight rotation round a vertical axis. It is one of the most superficial, and, as far as adaptation of the bony surfaces goes, one of the weakest joints, for in no position are the bones in more than partial contact. Its strength lies in the number, size, and arrangement of the ligaments, and the powerful muscles and fascial expansions which pass over the articulation and enable it to withstand the leverage of the two longest bones in the bodj\ It may be said'to consist of two articulations with a common synovial membrane — the patellofemoral and the tibio-femoral, the latter being double. It is composed of the condyles and trochlear surface of the femur, the condyles of the tibia, and the patella, united by the following ligaments, which may be divided into an external and internal set: —
The deep fascia of the thigh, as it descends to its attachment to the tuberosity and oblique lines of the tibia, not only overhes but blends with the fibrous expansion of the extensor tendons. The oblique lines of the tibia curve upward and backward from the tuberosity on each side to the postero-lateral part of the condyles. The process of fascia attached to the lateral ridge of the tibia and to the head of the fibula descends from the tensor fascise latas and is very thick and strong. It is firmly blended with the tendinous fibres of the vastus laterahs. The fascia lata, on the medial side of the patella, besides being attached to the medial oblique ridge of the tibia, sends some longitudinal fibres lower down to become blended with the fibrous expansion of the sartorius. The fascia is much thinner on the medial side of the patella than on the lateral, and blends much less with the tendon of the vastus niedialis than the lateral part of the fascia does with the vastus lateralis. A thin layer of the fascia lata in the form of transverse or aroiform fibres passes over the front of the joint. These fibres are speciaUy well marked over the ligamentum patellae, and blend here with the central portion of the quadriceps extensor fibres.
The fibrous expansion of the extensor tendons consists — (1) of a central portion, densely thick and strong, 3.7 cm. (1| in.) broad, which is inserted into the anterior two-thirds of the upper border of the patella, many of its superficial fibres passing over the subcutaneous surface of the bone into the ligamentum patellfe; (2) of two side portions thinner, but strong.
The side portions are inserted into the patella along its upper border on either side of the central portion and also into its medial and lateral borders, nearer the anterior than the posterior surface, as low down as the attachment of the ligamentum patellar; passing thence along the sides of the ligamentum patelte to the tibia, they are attached to the obhque lines which extend from the tuberosity to the medial and lateral condyles, and reach as far as the tibial and fibular collateral ligaments. On the lateral side, the fibres blend with the ilio-tibial band of the fascia lata, and on the medial they extend below the oblique line to blend with the periosteum of the shaft. Thus there is a large hood spread over the whole of the front of the joint, investing the patella, and reaching from the sides of the ligamentum pateUse to the collateral ligaments, attached below to the tibia, and separated everywhere from the synovial membrane by a layer ■of fatty tissue.
of the patella into the ligament. It is an extremely strong, flat band, attached above to the lower border of the patella; below, it is fixed to the lower part of the tuberosity and upper part of the crest of the tibia, somewhat obliquely, being prolonged downward further on the lateral side, so that this border is fully 2.5 cm. (1 in.) longer than the medial, which measures 6.7 cm. {2\ in.) in length. Behind, it is in contact with a mass of fat which separates it from the synovial membrane, and a small bursa intervenes between it and the head of the tibia. In front, a large bursa separates it from the subcutaneous tissue, and at the sides it is continuous with the fibrous expansion of the extensors.
Tibial collateral ligament
epicondyle of the femur, to the medial border and medial surface of the shaft of the tibia, 3.7 cm. (1| in.) below the condyle. It is 8.7 cm. (3| in.) long, well defined anteriorly, where it blends with the expansion of the conjoined extensor tendons; but not so well defined posteriorly, where it merges into the oblique popliteal ligament.
Some of the lower fibres blend with the descending portion of the semimembranosus tendon. Its deep surface is firmly adherent to the edge of the medial meniscus and coronary ligament, while part of the semimembranosus tendon and inferior medial articular vessels and nerve pass between it and the bone. Superficially, a bursa separates it from the tendons of the gracilis and semitendinosus muscles and from the aponeurosis of the sartorius muscle.
The fibular (external) collateral ligament (fig. 317) consists of two portions: the anterior, which is the longer and better marked, is a strong, rounded cord, about 5 cm. (2 in.) long, attached above to the tubercle on the lateral side of the lateral epicondyle of the femur, just below and in front of the origin of the lateral head of the gastrocnemius, whilst the tendon of the popliteus arises from the groove below and in front of it. Below, it is fixed to the middle of the lateral surface of the head of the fibula, 1.25 cm. (J) in. or more anterior to the apex.
Some fibres of the peroneus longus occasionally arise from the lower end of the ligament. The posterior portion is 8 mm. (\ in.) behind the anterior. It is broader and less defined; fixed below to the apex of the fibula, it inclines upward and somewhat backward, and ties down the popliteus against the lateral condyle of the tibia, blending beneath the lateral head of the gastrocnemius with the oblique popliteal ligament of the knee, of which it is really a portion.
The oblique popliteal ligament or ligamentum Winslowii (fig. 317) is a broad dense structure of interlacing fibres, with large orifices for vessels and nerves. It is attached above to the femur close to the articular margins of the condyles, stretching across the upper margin of the intercondyloid fossa, to which it is connected by fibro-fatty tissue; it thus reaches across from the tibial to the fibular collateral ligaments. Below, it is fixed to the border of the lateral condyle of the tibia, to the bone just below the posterior intercondyloid notch, and to the shaft of the tibia below the medial condyle, blending with the descending slip of the semimembranosus and tibial collateral ligament.
epicondyle of the femur, where it joins the lateral head of the gastrocnemius, a sesamoid plate being sometimes developed at the point of junction. This slip greatly strengthens the oblique pophteal ligament, of which, if not the chief constituent, it is at least a very important part.
Its deep surface is closely connected with the semilunar menisci (especially the medial) and coronary ligaments, and in the interval between the cartilages with the posterior crucial ligament and fibro-fatty tissue within the joint. Superficially it forms part of the floor of the popHteal space. A special band, the arcuate ligament, is sometimes found extending from the lateral epicondyle to the oblique ligament.
The articular capsule (fig. 319) is thin but strong, covering the synovial membrane, and looking like a loose sac. It is attached to the femur near the articular margin on the medial side, but further away on the lateral; it passes beneath the fibular collateral ligament to join the sheath of the popliteus. Medially it joins the tibial collateral ligament. Below, it is fixed to the upper as well as the medial and lateral borders of the patella and the anterior border of the head of the tibia. It is strengthened superficially between the femur and patella by an expansion from the articularis genu {suh-crureus) and is separated from
the fibrous expansion of the extensor tendon by a layer of fatty tissue. The synovial membrane lines its deep surface, and holds it against the borders of the semilunar menisci; it is also attached to the coronary ligaments.
The anterior crucial ligament (figs. 319 and 320) is strong and cord-like. It is attached to the medial half of the fossa in front of the intercondyloid eminence of the tibia, and to the lateral border of the medial articular facet as far back as the medial intercondyloid tubercle. It passes upward, backward, and laterally to the back part of the medial surface of the lateral condyle of the femur. To
Coronary ligament
the tibia, it is fixed behind the anterior extremity of the medial semilunar meniscus. Behind and to the lateral side it has the anterior extremity of the lateral meniscus, a few fibres of which blend with the lateral edge of the ligament.
Its anterior fibres at the tibial end are strongest and longest; being fixed highest on the femur; while the posterior, springing from the intercondyloid eminence, are shorter and more oblique. Near the spine, a slip is sometimes given off to the posterior crucial hgament.
The posterior crucial ligament (fig. 319, 320, and 322) is stronger and less oblique than the anterior. It is fixed below to the greater portion of the fossa behind the intercondyloid eminence of the tibia, especially the lateral and posterior portion, and then medially along the posterior intercondyloid fossa; being joined by fibres which arise between the intercondyloid tubercles, it ascends to the anterior part of the lateral surface of the medial condyle of the femur, having a wide crescentic attachment 1.5 cm. (f in.) in extent just above the articular surface.
horn of the medial semilunar meniscus, and receives a large slip from the lateral meniscus, which ascends along it, either in front or behind, to the femur; higher up in front it is connected with the anterior crucial hgament.
Until they rise above the intercondyloid eminence of the tibia the two crucial ligaments are closely bound together, so that no interspace exists between their tibial attachments and the point of decussation; the only space between them is therefore a v-shaped one corresponding to the upper half of their x-shaped arrangement, and this is a mere chink in the undissected state, and can be seen from the front only, owing to the fatty tissue beneath the synovial membrane which sm-rounds their femoral attachment.
The interarticular menisci or semilunar fibro-cartilages (figs. 319 and 320) are two crescentic discs resting upon tlie circumferential portions of the articular facets of the tibia, and moving with the tibia upon the femur. They somewhat deepen the tibial articular surfaces, and are dense and compact in structure, becoming looser and more fibrous near their extremities, where they are firmly fixed in front of and behind the intercondyloid eminence of the tibia. The circumferential border of each is convex, thick, and somewhat loosely attached to the borders of the condyles of the tibia by the coronary ligaments and the reflexion of the synovial membrane. The inner border is concave, thin, and free. Half an inch (1.3 cm.) broad at the widest part, they taper somewhat toward their
extremities, and cover rather less than two-thirds of the articular facets of the tibia. Their upper surfaces are slightly concave, and fit on to the femoral condyles, while the lower are flat and rest on the head of the tibia; both surfaces are smooth and covered by synovial membrane.
The lateral meniscus (fig. 320) is nearly circular in form and less firmly fixed than the medial, and consequently slides more freely upon the tibia. Its anterior cornu is attached to a narrow depression along the lateral articular facet, just in front of the lateral intercondyloid tubercle of the tibia, close to, and on the lateral side of, the anterior crucial hgament; a small slip from the cornu is often fixed to the tibia in front of the crucial ligament. The posterior cornu is firmly attached to the tibia behind the lateral intercondyloid tubercle, blending with the posterior crucial ligament, and giving off a well-marked fasciculus, which runs up along the anterior border of the ligament to be attached to the femur (ligament of Wrisberg). It also sends a narrow slip into the back part of the anterior crucial ligament. Its outer border is grooved toward its posterior part by the popliteus tendon, which is held to it by fibrous tissue and synovial membrane, and separates it from the fibular collateral hgament. From its anterior border is given off the transverse hgament.
The medial meniscus (fig. 320) is a segment of a larger circle than the lateral, and has an outline more oval than cuxular. Its anterior cornu is wide, and has a broad and oblique attachment to the anterior margin of the head of the tibia. It reaches from the margin of the condyle toward the middle of the fossa in front of the intercondyloid eminence, being altogether in front of the anterior crucial ligament. The posterior cornu is firmly fixed by a broad insertion in an antero-posterior line along the medial side of the posterior intercondyloid fossa, from the medial tubercle to the posterior margin of the head of the tibia. Its convex border is connected with the tibial collateral ligament and the seviimeinhrmiosus tendon.
The transverse ligament (figs. 319 and 320) is a rounded, slender, short cord, which extends from the convex border of the lateral meniscus to the concave border or anterior cornu of the medial, near which it is sometimes attached to the bone. It is an accessory band of the lateral meniscus, and is situated beneath the synovial membrane.
The coronary ligaments (fig. 319) connect the margins of the semilunar discs with the head of the tibia. The lateral is much more lax than the medial, permitting the lateral disc to change its position more freely than the medial. They are not in reality separate structures, but consist of fibres of the several surrounding ligaments of the knee-joint which become attached to the margins of the discs as they pass over them.
The synovial membrane (fig. 324) of the knee forms the largest synovial sac in the body. Bulging upward from the patella, it follows the capsule of the joint into a large cul-de-sac beneath the tendon of the extensor muscles on the front of the femur. It reaches some distance beyond the articular surface of the bone, and communicates very frequently with a large bursa interposed between the tendon and the femur above the line of attachment of the articular capsule. After investing the circumference of the lower end of the femur, it is reflected upon the
The synovial membrane covers a great portion of the crucial ligaments, but leaves uncovered the back of the posterior crucial where the latter is connected with the posterior hgament, and the lower part of both crucial ligaments where they are united. Thus the hgaments are completely shut out of the synovial cavity. Along the fibrous envelope the synovial membrane is conducted down to the semilunar menisci, over both surfaces of which it passes, and is reflected off the under surface on to the coronary ligaments, and thence down to the head of the tibia, around the circumference of which it extends a short way. It dips down between the external meniscus and the head of the tibia as low as the superior tibio-fibular ligament, reaching inward nearly as far as the intercondyloid notch, and forming a bursa for the play of the popliteal tendon.
At the back of the joint two pouches are prolonged beneath the muscles, one on each side between the condyle of the femur and the origin of the gastrocnemius. Large processes of synovial membrane also project into the joint, and being occupied by fat serve as padding to fill up spaces. The chief of these processes, the patellar synovial fold (ligamentum mucosum) (figs. 322 and 324), springs from the infrapatellar fatty mass. This so-called ligament is the central portion of the large process of synovial membrane, of which the alar folds form the free margins. It extends from the fatty mass, below the patella, backward and upward to the intercondyloid notch of the femur, where it is attached in front of the anterior crucial, and lateral to the posterior crucial ligament. Near the femur it is thin and transparent, consisting of a double fold of synovial membrane, but near the patella it contains some fatty tissue. Its anterior or upper edge ia free, and fully 2.6 cm. (an inch) long; the posterior or lower edge is half the length, and is attached to the crucial ligaments above, but is free below.
Passing backward from the capsule on each side of the patella is a prominent crescentic fold formed by reduplications of the synovial membrane — these are the alar folds (fig. 3?2). Their free margins are concave and thin, and are lost below in the patellar fold. There is a slight fossa above and another below each Ligament.
The arterial supply is derived from the art. genu suprema (anastomotica) ; the superior ajid inferior medial and lateral articular; the medial articular; the descending branch of the lateral circumflex; the anterior recurrent branch from the anterior tibial; and the posterior tibial recurrent.
The nerve-supply comes from the great sciatic, femoral, and obturator sources. The great sciatic pves off the tibial and common peroneal; the tibial sends tAvo, sometimes three bi'anches — one with the medial articular artery; one with the inferior medial, and sometimes one with the superior medial articular artery; the common peroneal gives a branch which accompanies the superior, and another which accompanies the inferior articular artery, and a recurrent branch which follows the course of the anterior recm-rent branch of the anterior tibial artery. The femoral sends an articular branch from the nerve to the vastus lateralis; a second from the nerve to the vastus mediaiis; and sometimes a third from that to the vastus intermedins. Thus there are three articular twigs to the knee derived from the muscular branches of the femoral. The obturator by its deep division sends a branch through the adductor magnus on to the popliteal artery, which enters the joint posteriorly.
Relations. — Anteriorly and at the sides the knee-joint is merely covered and protectedlby skin, fascia, and the tendinous expansions of the quadriceps extensor muscle. Laterally and posteriorly it is crossed by the biceps tendon. Medially and posteriorly lie the sartorius and the tendons of the gracilis and seinitendinosus muscles. Posteriorly it is in relation with the popliteal vessels and nerves, the semimembranosus, the two heads of the gastrocnemius, and the plantaris. The tendon of the popliteus pierces the capsule behind and medial to the biceps tendon.
The movements which occur at the knee-joint are flexion and extension, with some slight amount of rotation in the bent position. These movements are not so simple as the corresponding ones at the elbow, for the knee is not a simple hinge joint. The movements of rotation instead of occurring between tibia and fibula, as between radius and ulna, are movements of the tibia with the fibula upon the condyles of the femur.
the flexed position, the posterior part of the articular surface of the tibia is in contact with the rounded bacli part of the femoral condyles; in the semiflexed position the middle parts of the tibial facets Articulate with the anterior rounded part of the condyles; while in the fully extended position the anterior and middle parts of the tibial facets are in contact with the anterior flattened portion of the condyles. So with the patella: in extreme flexion the medial articular facet rests on the lateral part of the medial condyle of the femur; in flexion the upper pair of facets rests on the lower part of the trochlear surface of the femur; in mid-flexion the middle panrests on the middle of the trochlear surface; while in extension the lower pair of facets on the patella rests on the upper portion of the trochlear surface of the femur.
2. It differs from a true hinge in that, in passing from a state of extension to one of flexion, the tibia does not revolve round a single transverse axis drawn through the lower end of the femur, as the ulna does round the lower end of the humerus. The articular surface of the tibia slides forward in e.xtension and backward in flexion; thus the axis round which the tibia revolves upon the femur is a shifting one, as is seen by reference to fig. 325, B, C, D.
3. Another point of difference is that extension is accompanied by lateral rotation, and flexion by medial rotation. This rotation occurs round a vertical axis drawn through the middle of the lateral condyle of the femur and the lateral condyle of the tibia, and is most marked at the termination of extension and at the commencement of flexion. This rotation of the leg at the knee is a true rotation about a vertical axis, and thus differs from the obliquity of the flexion
extension are relaxed during flexion, and thereby a considerable amount of rotatory movement is- permitted in the flexed position. The axis of this rotation is vertical, and passes through the medial intercondyloid tubercle of the tibia, so that the lateral condyle moves in the arc of a larger circle than does the medial, and is therefore required to move more freely and easily;
In extension, all the ligaments are on the stretch with the exception of the ligamentum patellae and front of the capsule. Extension is checked by both the crucial ligaments and the cSlateral ligaments (figs. 325, A, B, and 326).
In flexion the ligamentum patellae and anterior portion of the capsule are on the stretch; so also is the posterior crucial in extreme flexion, though it is not quite tight in the semiflexed state of the joint. All the other ligaments are relaxed (fig. 325, C, D), although the relaxation of the anterior crucial ligament is slight in extreme flexion (fig. 327). Flexion is only checked during hfe by the contact of the soft parts, i. e., the calf with the back of the thigh.
especially by the anterior, and sliding backward by the posterior crucial.
Muscles which act upon the knee-joint. — Flexors. — Biceps, semimembranosus, semitendinosus, sartorius, gastrocnemius, plantaris, and pophteus. Extensor. — Quadriceps extensor. Medial Bolators. — Sartorius, gracilis, semitendinosus, semimembranosus, popliteus. Lateral Rotator. — Biceps.
The fibula is connected with the tibia throughout its length by an interosseous membrane, and at the upper and lower extremities by means of two joints. Very little movement is permitted between the two bones.
(a) The superior tibio-fibular joint. (6) The middle tibio-fibular union. (c) The inferior tibio-fibular joint.
The superior tibio-fibular joint is about 6 mm. (J in.) below, and quite distinct from, the knee at its upper and anterior part; but at its posterior and superior aspect, where the border of the lateral condyle of the tibia is bevelled by the popliteus muscle, the joint is in the closest proximity to the bursa beneath the tendon of that muscle, and is only separated from the knee-joint by a thin septum of areolar tissue. There is often a communication between the synovial cavities of the two joints. The ligaments uniting the bones are: —
The articular capsule is a well-marked fibro-areolar structure; it is attached close round the articular margins of the tibia and fibula. In front it is shut off completely from the knee-joint by the capsule of the knee and the coronary ligament; but behind, it is often very thin, and may communicate with the bursa under the pophteus tendon.
The anterior tibio-fibular (capitular) ligament (fig. 326) consists of a few fibres which pass upward and medially from the fibula to the tibia. It lies beneath the anterior portion of the tendon of the biceps.
The posterior tibio-fibular (capitular) ligament (fig. 317) consists of a few fibres which pass upward and medially between the adjacent bones, from the head of the fibula to the lateral condyle of the tibia.
The superior interosseous ligament consists of a mass of dense yellow fibroareolar tissue, binding the opposed surfaces of the bones together for 2 cm. (f in.) below the articular facets. It is continuous with the interosseous membrane along the tibia.
The biceps tendon is divided by the fibular collateral ligament of the knee; of the two divisions the anterior is by far the stronger, and is inserted into the lateral condyle of the tibia as well as to the front of the head of the fibula, and thus the muscle, acting on both bones, tends to brace them more tightly together; indeed, it holds the bones strongly together after all other connections have been severed.
of the common peroneal.
Relations. — In front, the upper ends of the tibialis anterior, the extensor digitorum longus, and the peroneus longus. Behind, the tendon of the popliteus overlapped by the lateral head of the gastrocnemius. Laterally, the biceps tendon and the common peroneal nerve. Below and medially, the anterior tibial vessels.
the weight to the foot. The articular facet of the tibia overhangs, and is received upon the articular facet of the head of the fibula in an oblique plane. This joint allows of slight yielding of the lateral malleolus during flexion and extension of the ankle-joint, the whole fibula gUding slightly upward in flexion, and downward in extension, of the anlde.
The interosseous membrane is attached along the lateral border of the tibia and the interosseous border of the fibula. It is deficient above for about 2.5 cm. (1 in.) or more, measured from the under aspect of the superior joint. Its upper border is concave, and over it pass the anterior tibial vessels.
The membrane consists of a thin aponeurotic and translucent lamina, formed of oblique fine fibres, some of which run from the tibia to the fibula, and some from the fibula to the tibia, but all are inchned downward. They are best marked at their attachment to the bones, and gradually grow denser and thicker as they approach the inferior interosseous ligament. The
Fig. 328. — Lower Ends op Left Tebia and Fibula, showing the Ligaments. The synovial fold between these bones has been removed to show the transverse ligament forming part of the capsule of the joint, and the deeper fibres of the anterior lateral malleolar hgament which come into contact with the talus. (From a dissection by Mr. W. Pearson, of the Royal College of Surgeons' Museum.)
with the inferior interosseous ligament.
In front of the interosseous membrane lie the tibialis anterior, the extensor digitorum longus, the extensor hallucis longus, and the anterior tibial vessels and nerves. Behind it is in relation with the tibialis posterior, the flexor hallucis longus, and the peroneal artery.
This junction is formed by the lower ends of the tibia and fibula. The rough triangular surface on each of these bones formed by the bifurcation of their interosseous lines is closely and firmly united by the inferior interosseous ligament. The fibula is in actual contact with the tibia by an articular facet, which is small in size, crescentic in shape, and continuous with the articular facet of the malleolus.
The anterior lateral malleolar ligament (anterior inferior tibio-fibular ligament) (figs. 328 and 334) is a strong triangular band about 2 cm. (f in.) wide, and is attached to the lower extremity of the tibia at its anterior and lateral angle, close to the margin of the facet for the talus and passes downward and
The fibres increase in length from above downward. In front it is in relation with the peroneus tertius and deep fascia of the leg, and gives origin to fibres of the anterior Kgament of the ankle-joint. Behind, it Lies in contact with the interosseous Ugament, and comes into contact with the articxilar surface of the talus (see figs. 328 and 329).
The posterior lateral malleolar ligament (figs. 328 and 334) is very similar to the anterior, extending from the posterior and lateral angle of the lower end of the tibia downward and laterally to the lowest 1.5 cm. (| in.) of the border separating the medial from the posterior surface of the shaft of the fibula, and to the upper part of the posterior border of the lateral malleolus. It is in relation in front with the interosseous ligament; below, it touches the transverse ligament.
Deltoid ligament
tibia and fibula, except for 1 cm. (f in.) at the extremity, where there is a synovial cavity. It extends from the anterior to the posterior lateral malleolar hgaments, reaching upward 4 cm. (l-J- in.) in front, but only half this height behind.
The transverse ligament (fig. 331) is a strong rounded band, attached to nearly the whole length of the inferior border of the posterior svu-face of the tibia, just above the articular facet for the talus. It then inclines a little forward and downward, to be attached to the medial surface of the lateral malleolus, just above the fossa, and into the upper part of the fossa itself.
Relations.
The movement permitted at this joint is a mere gliding, chiefly in an upward and downward direction, of the fibula on the tibia. The bones are firmly braced together and yet form a slightly yielding arch, thus allowing a slight side to side expansion during extreme flexion, when the broad part of the talus is brought under the arch, by the upward gliding of the fibula on the tibia. To this end the direction of the fibres of the lateral malleolar ligaments is downward from tibia to fibula. This mechanical arrangement secures perfect contact of the articular surfaces of the ankle-joint in all positions of the foot.
The ankle [articulatio talo-cruralis] is a perfect ginglymus or hinge joint. The bones which enter into its formation are: the lower extremity and medial malleolus of the tibia, and the lateral malleolus of the fibula, above; and the upper
The anterior ligament (fig. 334) is a thin, membranous structure, which completes the capsule in front of the joint. It is attached above to the anterior border of the medial malleolus, to a crest of bone just above the transverse groove at the lower end of the tibia, to the anterior lateral malleolar ligament, and to the anterior border of the lateral malleolus. Below, it is attached to the rough upper surface of the neck of the talus (astragalus). Medially it is thicker, and is fixed to the talus close to the facet for the medial malleolus, being continuous with the deltoid ligament, and passing forward to blend with the talo-navicular ligament. Laterally it is attached to the talus, just below and in front of the angle between the superior and lateral facets, close to their edges, and joins the anterior talofibular ligament.
The posterior ligament (fig. 331) is a very thin and disconnected membranous structure, connected above with the lateral malleolus, medial to the peroneal groove; to the posterior margin of the lower end of the tibia lateral to the groove for the tibialis posterior; and to the posterior lateral malleolar ligament. Below, it is attached to the posterior surface of the talus from the deltoid to the lateral ligaments. The passage of the flexor hallucis longus tendon over the back of the joint serves the purpose of a much stronger posterior ligament.
The deltoid ligament (fig. 330) is attached superiorly to the medial malleolus along its lower border, and to its anterior surface superficial to the anterior ligament; some very strong fibres are fixed to the notch in the lower border of the malleolus, and, getting attachment below to the rough depression on the medial side of the talus, form a deep portion to the ligament. The ligament radiates; the posterior fibres are short, and incline a little backward to be fixed to the rough medial surface of the talus, close to the superior articular facet, and into the
tubercle to the medial side of the flexor hallucis longus groove. The fibres next in front are numerous and form a thick and strong mass, filling up the rough depression on the medial surface of the talus, whilst some pass over the talocalcaneal joint to the upper and medial border of the sustentaculum tali. The fibres which are connected above with the anterior surface of the malleolus pass downward and somewhat forward to be attached to the navicular and to the margin of the calcaneo-navicular ligament.
The lateral ligament (figs. 329 and 334) consists of three distinct slips (fasciculi). The anterior talc -fibular ligament (anterior fasciculus), is ribbon-like and passes from the anterior border of the lateral malleolus near the tip to the rough surface of the talus in front of the lateral facet, and overhanging the sinus pedis. The calcaneo -fibular ligament (middle fasciculus) , is a strong roundish bundle, which extends downward and somewhat backward from the anterior border of the lateral malleolus close to the attachment of the anterior fasciculus, and from the lateral surface of the malleolus, just in front of the apex, to a tubercle on the middle of the lateral surface of the calcaneum. The posterior talo-
fibular ligament (posterior fasciculus), is almost horizontal; it is a strong, thick band attached at one end to the posterior border of the malleolus, and slightly to the fossa on the medial surface; and at the other end to the talus, behind the articular facet for the fibula, as well as to a tubercle on the lateral side of the groove for
malleolus.
The synovial membrane is very extensive. Besides lining the ligaments of the ankle, it extends upward between the tibia and fibula, forming a short culde-sac as far as the interosseous ligament. Upon the anterior and posterior ligaments it is very loose, and extends beyond the limits of the articulation. It is said to contain more synovia than any other joint.
the posterior tibial, and posterior peroneal.
Relations. — In front and in contact with the anterior hgament, from medial to lateral aspects, are the tendons of the tibiahs anterior, the tendon of the extensor haUucis longus, the anterior tibial vessels, the anterior tibial nerve, the tendons of the extensor digitorum longus, and the tendon of the peroneus tertius. To the medial side of the tibiahs anterior and to the lateral side of the peroneus tertius the joint is subcutaneous anteriorly. Behind and laterally are the tendons of the peroneus longus and brevis. Behind and medially, from medial to lateral side, are the tendon of the tibialis posterior, the tendon of the flexor digitorum longus, the posterior tibial vessels, the posterior tibial nerve, and the tendon of the flexor hallucis longus. Directly behind is a pad of fat which intervenes between the tendo Achillis and the joint. Below and on the lateral side, crossing the middle fasciculus of the lateral ligament, are the tendons of the peroneus longus and brevis. Below and on the medial side, crossing the deltoid ligament, are the tendons of the tibialis posterior and the flexor digitorum longus.
Movements. — This being a true hinge joint, flexion and extension are the only movements of which it is capable, there being no side to side motion, except in extreme extension, when the narrowest part of the talus is thrust forward into the widest part of the tibio-fibular arch.
In flexion the talus is tightly embraced by the malleoli, and side to side movement is impossible. Flexion of the ankle-joint is hmited by: — (i) nearly the whole of the fibres of the deltoid ligament, none but the most anterior being relaxed; (ii) the posterior and middle portions of the lateral ligament, especially the posterior; (iii) the posterior ligament of the ankle. It is also hmited by the neck of the talus abutting on the edge of the tibia.
In most European ankle-joints the anterior edge of the lower end of the tibia is kept from actual contact with the neck of the talus in positions of extreme flexion by the intervention of a pad of fat situated beneath the anterior extension of the anterior hgament. In races which adopt a squatting posture, however, an actual articulation may be developed between these two bony surfaces, a facet being present both upon the anterior margin of the tibia and upon the neck of the talus. These facets are known as "squatting facets" (fig. 333, A) and are of common occurrence in ancient bones and in the bones of modern oriental people.
Extension of the ankle-joint is limited by: — (i) the anterior fibres of the deltoid ligament; (ii) the anterior and middle portions of the lateral hgament; (ui) the medial and stronger fibres of the anterior hgament. It is also limited by the posterior portion of the talus meeting with the tibia. Thus the middle portion of the lateral ligament is always on the stretch, owing to its obliquely backward direction, whereby it hmits flexion; and its attachment to the fibula in front of the malleolar apex, whereby it prevents over-extension as soon as the foot begins to twist
medialward. .This medial twisting, or adduction of the foot, is partly due to the greater posterior length of the medial border of the superior articular surface of the talus, and to the less proportionate height posteriorly of the lateral border of that surface, but chiefly to the side to side movement in the talo-calcaneal joints. Fle.xion and extension take place round a transverse axis drawn through the body of the talus. The movement is not in a direct antero-posterior plane, but on a plane inclined forward and laterally from the middle of the astragalus to the intermetatarsal joint of the second and third toes.
Muscles which act on the ankle-joint. — Flexors. — Tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus tertius. Extensors. — Tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus, peroneus brevis, soleus, gastrocnemius, plantaris.
Fig. 333. — Anterior Aspect of the Lower Extremity op the Tibia. In A, the articular surface is prolonged upward in front, forming a "squatting facet" which articulates with a corresponding facet on the neck of the talus. In B (the usual condition) the articular surface is confined to the lower aspect of the bone.
'. The calcaneus articulates with the talus by two joints, the anterior and posterior: the former communicates with the medio-tarsal; the posterior is separate and complete in itself. At the latter joint the two bones are united by an articular capsule with the following ligaments: —
The interosseous ligament (figs. 334 and 335) is a strong band connecting the apposed surfaces of the calcaneus and talus along their oblique grooves. It is composed of several vertical laminae of fibres, with some fatty tissue in between.
It is better marked, deeper, and broader laterally. Strong laminse extend from the rough inferior and lateral sm-faces of the neck of the talus to the rough superior surface of the calcaneus anteriorly, forming the posterior boundary of the anterior talo-caloaneal joint; these have been described as the anterior (interosseous) ligament. The posterior lamina extend from the roof of the sinus pedis to the calcaneus immediately in front of the lateral facet, thus forming the anterior part of the capsule of the posterior joint.
The lateral talo-calcaneal ligament (fig. 334) extends from the groove just below and in front of the lateral articular facet of the talus, to the calcaneus some little distance from the articular margin. Its fibres are nearly parallel with those of the calcaneo-fibular ligament of the ankle, which passes over it and adds to its strength. It fiUs up the interval between the calcaneofibular and anterior talo-fibular ligaments, a considerable bundle of its fibres blending with the anterior border of the calcaneo-fibular.
articular margin.
The medial talo-calcaneal ligament includes two portions. The first is a narrow band of well-marked fibres passing obliquely downward and forward from the medial tubercle of the talus, just behind the medial end of the sinus tarsi, to the calcaneus behind the sustentaculum tali, thus completing the floor of the groove for the flexor hallucis longus tendon. The second portion, which is often considered a separate ligament, is described below with the anterior talo-calcaneal joint.
This joint is formed by the anterior facet on the upper surface of the calcaneus and the facets on the lower surface of the neck and head of the talus; it is bounded on the sides and behind by ligaments, and communicates anteriorly with the talo-navicular joint. The ligaments are: —
already described.
The medial talo-calcaneal ligament (second portion; see above) consists of short fibres attached above to the medial surface of the neck of the talus, and below to the upper edge of the free border of the sustentaculum tali, blending posteriorly with the medial extremityof the interosseous ligament, and anteriorly with the upper border of the plantar calcaneo-navicular ligament. It is strengthened by the deltoid ligament, the anterior fibres of which are also attached to the plantar calcaneo-navicular ligament.
The lateral calcaneo-navicular (figs. 334 and 335) limits this, as well as the talo-navicular joint, on the lateral side. It is a strong, well-marked band, extending from thorough upper surface of the calcaneus, lateral to the anterior facet, to a slight groove on the lateral surface of the navicular near the posterior margin. It blends below with the plantar calcaneo-navicular, and above with the talo-navicular ligament. Its fibres run obliquely forward and medially. The deltoid ligament and middle fasciculus of the lateral ligament of the ankle-joint also add to the security of these two joints, and assist in limiting movements between the bones by passing over the talus to the calcaneus.
The movements of which these two joints are capable are adduction and abduction, with some amount of rotation. Adduction, or inclination of the sole medialward, is combined with some medial rotation of the toes, and some lateral rotation of the heel; while abduction, or inclination of the foot lateralward, is associated with turning of the toes laterally and the heel medially. Thus the variety and the range of movements of the foot on the leg, which at the ankle are almost limited to flexion and extension, are increased. The cuboid moves with the calcaneus, while the navicular revolves on the head of the talus.
In walking, the heel is first placed on the ground; the foot is slightly adducted; but as the body swings forward, first the latei-al then the medial toes touch the ground, the talus presses against the navicular and sinks upon the plantar calcaneo-navicular ligament; the foot then becomes slightly abducted. When the foot is firmly placed on the ground, the weight is transmitted to it obliquely downward and medially, so that if the ligaments between the calcaneus and talus did not check abduction, medial displacement of the talus from the tibio-fibular arch would only be prevented by the tendons passing round the medial ankle (especially the tibialis posterior). If the ligaments be too weak to limit abduction, the weight of the body increases it, and forces the medial malleolus and talus downward and medially, giving rise to flat foot.
the whole weight of the body when the heel is first placed on the ground; (ii) by the upward pressure of this facet against the talus it transfers the weight to the ball of the toes as the heel is raised, the posterior edge of the sustentaculum tali and the anterior and lateral part of the upper surface of the calcaneus preventing the talus from being displaced too far forward by the superincumbent weight; and (iii) the calcaneus serves to suspend the talus when, with the heel raised by muscular action, the other foot is being swung forward.
The dorsal cuboideo-navicular ligament (fig. 334) runs forward and laterally from the lateral end of the dorsal surface of the navicular to the middle third of the medial border of the cuboid on its dorsal aspect, passing over the posterior lateral angle of the third cuneiform bone. It is wider laterally.
The plantar cuboideo-navicular ligament is a well-marked strong band, which runs forward and laterally, from the plantar surface of the navicular to the depression on the medial siurface of the cuboid, and slightly into the plantar surface just below it.
The interosseous cuboideo-navicular ligament is a strong band which passes between the apposed surfaces of these bones from the dorsal to the plantar ligaments. Some of its posterior fibres reach the plantar surface of the foot behind the cuboideo-navicular ligament, and radiate laterally and backward over the medial border of the cuboid to blend with the anterior extremity of the plantar calcaneo-cuboid ligament.
Medial.
The dorsal cuneo-navicular ligament is very strong, and stretches as a continuous structure on the dorsal surface of the navicular, between the tubercle of the navicular on the medial side, and the dorsal cuboideo-navicular ligament laterally, passing forward and a little laterally to the dorsal surfaces of the three cuneiform bones.
The medial cuneo-navicular ligament is a very strong thick band which connects the tubercle of the navicular with the medial surface of the first cuneiform bone. It is continuous with the dorsal and plantar ligaments. Its lower border touches the tendon of the tibialis posterior.
The plantar cuneo-navicular ligament forms, like the dorsal, a continuous structure extending between the plantar surfaces of the bones. Its fibres pass forward and laterally. It is in relation below with the tendon of the tibialis posterior.
It must be noticed that the expanded tendon of insertion of the tibialis posterior, and the ligaments uniting the navicular with the cuboid and cuneiform bones, pass forward and lateraUy, while the peroneus longus tendon and the ligaments uniting the first and second rows of bones, except the medial half of the dorsal talo-navicular ligaments, pass forward and medially. This arrangement is admirably adapted to preserve the arches of the foot, and especially the transverse arch. Had these tendons and ligaments run directly forward, all the strain on the transverse arch would have fallen on the interosseous ligaments, but as it is, the arch is braced up by the above-mentioned structures.
The dorsal ligaments are three in number, two, the dorsal intercuneiform, connecting the three cuneiform bones, and a thhd, the dorsal cuneo-cuboid, uniting the third cuneiform with the cuboid. They pass between the contiguous margins of the bones, and are blended behind with the dorsal ligaments of the cuboideo-navicular and cuneo-navicular joints.
The plantar ligaments are two in number: a very strong one, the plantar intercuneiform, passes laterally and forward from the lateral side of the base of the first cuneiform to the apex of the second cuneiform, winding somewhat to its lateral side. The second, the plantar cuneocuboid, connects the apex of the third cuneiform with the anterior half of the medial surface of the cuboid along its plantar border, joining with the plantar cuboideo-navicular hgament behind.
The interosseous ligaments are three in number. They are strong and deep masses of ligamentous tissue which connect the second cuneiform with the first and third cuneiform bones, and the third cuneiform with the cuboid; occupying all the non-articular portions of the apposed surfaces of the bones. The ligaments extend the whole vertical depth between the second cuneiform and the third, and the third cuneiform and the cuboid, and blend with the dorsal and plantar ligaments; they are situated in front of the articular facets, and completely shut off the synovial cavity behind from that in front. The hgament between the first and second cuneiform bones occupies the inferior and anterior two-thirds of the apposed surfaces, and does not generally extend high enough to separate the synovial cavity of the anterior tarsal joint from that of the second and third metatarsal and cuneiform bones. If it does extend to the dorsal surface, it divides the facets completely from one another, making a seventh synovial sac in the foot.
The arterial supply is from the metatarsal and plantar arteries.
The nerves are derived from the deep peroneal and medial and lateral plantar. The movement permitted in these joints is very limited, and exists only for the purpose of adding to the general pliancy and elasticity of the tarsus without allowing any sensible alteration in the position of the dilferent parts of the foot, as the medio-tarsal and talo-calcaneal joints do. It is simply a gUding motion, and either deepens or widens the transverse arch. The third cuneiform being wedged in between the others is less movable, and so forms a pivot upon which the rest can move. The movement is more produced by the weight of the body than by direct muscular action; and of the muscles attached to this part of the tarsus, all deepen the arch save the tibiahs anterior, which pulls the first cuneiform up, and so tends to widen it.
The articulations of the anterior and posterior portions of the tarsus, although in the same transverse line, consist of two separate joints, viz., (i) a medial, the talo-navicular, which communicates with the anterior talo-calcaneal articulation; and (ii) a lateral, the calcaneo-cuboid, which is complete in itself. The movements of the anterior upon the posterior portions of the foot take place at these joints simultaneously. It will be most convenient to deal with the joints separately as regards the ligaments; while the arteries, nerves, and movements will be considered together.
This is the only ball-and-socket joint in the tarsus. It communicates with the anterior talo-calcaneal articulation, and two of the ligaments which close it in do not touch the talus, but pass from the calcaneus to the navicular. The uniting ligaments include, in addition to the articular capsule, the following: —
The plantar calcaneo-navicular ligament (figs. 335 and 336) is an exceedingly dense, thick plate of fibro-elastio tissue. It extends from the sustentaculum tali and the under surface of the calcaneus in front of a ridge curving laterally to the anterior tubercle of that bone, to the
whole width of the inferior surface of the navicular, and also to the medial surface of the navicular behind the tubercle. Medially it is blended with the anterior portion of the deltoid ligament of the ankle, and laterally with the lower border of the lateral calcaneo-navicular hgament. It is thickest along the medial border. Its upper surface loses the well-marked fibrous appearance which the ligament has in the sole, and becomes smooth and faceted. In contact with the under surface of the ligament the tendon of the libialis posterior passes, giving considerable support to the head of the talus by assisting the power and protecting the spring of the ligament. The fibres of the ligament run forward and mediaUy. On account of its elasticity it is sometimes termed the spring ligament.
The talo -navicular ligament is a broad, thin, but well-marked layer of fibres which passes from the dorsal and lateral surfaces of the neck of the talus to the whole length of the dorsal surface of the navicular. Many of the fibres converge to their insertion on the navicular. The fibres low down on the lateral side blend a little way from their origin with the upper edge of the lateral calcaneo-navicular ligament, and then pass forward and medially to the navicular; those next above pass obliquely and with a distinct twist over the upper and lateral side of the head of the talus to the centre of the dorsum of the navicular, overlapping fibres from the medial side of the talus as well as some from the anterior ligament of the ankle-joint.
The medial calcaneo-cuboid ligament (fig. 335) is a strong band of fibres attached to the calcaneus along the medial jiiirt ol' the non-articular ridge above the articular facet for the cuboid, and also to the upper part of tlie medial surface close to the articular margin, and passes forward to be attached to the depression on the medial surface of the cuboid, and also to the rough angle
Insertion of peroneus longus
between the medial and inferior surfaces. At the calcaneus this ligament is closely connected with the lateral calcaneo-navicular Mgament. Toward the sole it is connected with the plantar calcaneo-cuboid ligament, and superiorly with the dorsal calcaneo-cuboid.
The dorsal calcaneo-cuboid (fig. 335) is attached to the dorsal surfaces of the two bones, extending low down laterally to blend with the lateral part of the plantar calcaneo-cuboid ligament. Over the medial half, or more, the ligament stretches some distance beyond the margins of the articular surfaces, reaching well forward upon the cuboid to be attached about midway between its anterior and posterior borders; but toward the lateral side, the ligament is much shorter, and is attached to the cuboid behind its tubercle.
The long plantar ligament (fig. 336) is a strong, dense band of fibres which is attached posteriorly to the whole of the inferior surface of the calcaneus between the posterior tubercles and the rounded eminence (the anterior tubercle) at the anterior end of the bone. Most of its fibres pass directly forward, and are fixed to the lateral two-thirds or more of the oblique ridge behind the peroneal groove on the cuboid, while some pass further forward and medially, expanding into a broad layer, and are inserted into the bases of the second, thu-d, fourth, and medial half of the fifth metatarsal bones. This anterior expanded portion completes the canal for the peroneus hiugiiK tvndnn, and from its under surface arise the oblique adductor hallucis and the flexor quinii iliijili lircris muscles.
The plantar calcaneo-cuboid (short plantar) (fig. 336) is attached to the rounded eminence (anterior tubercle) at the anterior end of the under surface of the calcaneus, and to the bone in front of it, and then takes an oblique course forward and medially, and is attached to the whole of the depressed inferior surface of the cuboid behind the oblique ridge, except its lateral angle. It is strongest near its lateral edge, and is formed by dense strong fibres.
peroneal, and occasionally from the superficial peroneal or lateral plantar.
Relations. — On the dorsal aspect of the mid-tarsal joint lie the tendons of the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius, the muscular part of the extensor digitorum brevis, the dorsalis pedis artery, and the anterior tibial nerve. On its plantar aspect are the tendons of the flexor digitorum longus and hallucis longus, quadratus plantse (accessorius), and the medial and lateral plantar vessels and nerves. It is crossed laterally by the tendons of the peroneus longus and brevis and medially by the tendon of the tibialis posterior.
The movements which take place at the medio-tarsal joints are mainly flexion and extension, with superadded side-to-side and rotatory movements. Flexion at these joints is simultaneous with extension of the ankle, and vice versa. Flexion and extension do not take place upon a transverse, but round an oblique, axis which passes from the medial to the lateral side, and somewhat backward and downward through the talus and calcaneus.
Combined with flexion and extension is also some rotatory motion round an antero-posterior axis which turns the medial or lateral border of the foot upward. There is also a fail' amount of side-to-side motion whereby the foot can be inclined medially (i. e., adducted) or laterally (i. e., abducted).
These movements of the medio-tarsal joint occur in conjunction with those of the ankle' a,nd talo-calcaneal joints. Rotation at the talo-calcaneal joint is, however, round a vertical axis in a horizontal plane, and so turns the toes medially or laterally; whereas at the mediotarsal union the axis is antero-posterior and the medial or lateral edge of the foot is turned upward. Gliding at the talo-calcaneal joint elevates or depresses the edge of the foot, while at the medio-tarsal it adducts or abducts the toes without altering the relative position of the calcaneus to the talus.
Thus flexion at the medio-tarsal joint is associated with adduction and medial rotation of the foot, occurring simultaneously with extension of the ankle; and extension at the mediotarsal joint is associated with abduction and lateral rotation, occurring simultaneously with flexion of the ankle.
Flexion and medial rotation are far more free than extension and lateral rotation, which latter movements are arrested by the ligaments of the sole as soon as the foot is brought into the position in which it rests on the ground.
Although the talo-navicular is a baU-and-socket joint, yet, owing to the union of the navicular with the cuboid, its movements are limited by the shape of the calcaneo-cuboid joint; this latter being concavo-convex from above downward, prevents rotation round a vertical axis, and also any side-to-side motion except in a direction obliquely downward and mediaUy, and upward and laterally. This is also the direction of freest movement at the talo-navicular joint. Movement is also limited by the ligamentous union of the calcaneus with the navicular. The twisting movement of the foot, such as turning it upon its medial or lateral edge, and the increase or diminution of the arch, take place at the tarsal joints, especially the medio-tarsal and talocalcaneal articulations. Here too those changes occur which, owing to paralysis of some muscles or contraction of others, result in talipes equino-varus, or valgus.
Muscles which act on the mid-tarsal joint. — Medial rotators. — Tibialis anterior and posterior acting simultaneously; they are aided by the flexor digitorum longus and flexor hallucis longus. Lateral rotators. — The peronei longus, brevis, and tertius, acting simultaneously. They are aided by the extensor digitorum longus.
A complete articular capsule unites the first metatarsal with the first cuneiform, the fibres of which are very thick on the inferior and medial aspects; those on the lateral side pass from behind forward in the interval between the interosseous ligaments which connect the two bones forming this joint with the second metatarsal. The ligament on the plantar aspect is by far the strongest, and blends at the cuneiform bone with the cuneo-navicular ligament.
Into this union there enter the three cuneiform and second and third metatarsal bones, which are bound together by the following ligaments (supplementary to the articular capsule) : dorsal, plantar, interosseous.
The dorsal ligaments. — 1. Some short fibres cross obliquely from the lateral edge of the first cuneiform bone to the medial border of the base of the second metatarsal bone; they take the place of a dorsal metatarsal hgament, which is wanting between the first and second metatarsal bones.
run directly forward.
3. The third cuneiform is connected with (1) the lateral corner of the second metatarsal bone by a narrow band passing obliquely medially; (2) with the third metatarsal by fibres passing directly forward; and (3) with the fourth metatarsal by a short band passing obUquely laterally to the medial edge of its base.
The plantar ligaments. — A strong hgament unites the first cuneiform and the bases of the second and third metatarsal bones. The tibialis posterior is inserted into these bones close beside it. Other slender ligaments connect the second cuneiform with the second, and the third cuneiform with the third metatarsal bones.
The interosseous ligaments. — (1) A strong broad interosseous hgament extends between the lateral surface of the first cuneiform and the medial surface of the base of the second metatarsal bone. It is attached to both bones below and in front of the articular facets, and separates the intermediate [from the medial tarso-metatarsal joint. (2) A second band is attached behind to a fossa on the anterior and lateral edge of the third cuneiform and to the interosseous ligament between it and the cuboid, and passes horizontally forward to be attached to the whole depth of the fourth metatarsal bone behind its medial facet, and to the opposed surfaces of the third and fourth below the articular facets upon their sides. It separates the middle tarsometatarsal, and intermetatarsal between the third and fourth bones, from the oubo-metatarsal joint. It is more firmly connected with the third bone than with the fourth. (3) A slender ligament composed only of a few fibres often passes from a small tubercle on the medial and anterior edge of the third cuneiform to a groove on the lateral edge of the second metatarsal bone between the two facets upon then- sides.
The movements permitted at these joints are flexion and extension of the metatarsus on the tarsus; and at the medial and lateral divisions, slight adduction and abduction. In the lateral, the side-to-side motion is freer than in the medial joint, and freest between the fifth metatarsal bone and the cuboid. In the medial joint, flexion is combined with sUght abduction and extension with abduction.
There is also a little gliding, which aflows the transverse arch to be increased or diminished in depth; the medial and lateral two bones sliding downward, and the two middle a little upward, when the arch is increased; and vice versa when the arch is flattened.
The bones comprising this joint are the fourth and fifth metatarsal and the anterior surface of the cuboid, firmly connected on all sides by the articular capsule, strengthened by the following ligaments: —
INTERMETATARSAL JOINTS
continuous along the groove at the base of the fifth metatarsal bone with the dorsal ligament, and as it passes round the lateral border of the foot it is somewhat thickened, and may be described as the lateral cubo-metatarsal ligament. On its medial side it joins the interosseous ligaments, thus completing the capsule below. It is not a thick structure, and to see it the long plantar ligament, the peroneus longus, and lateral slip of the tibialis posterior must be removed; the attachment of these structures to the fourth and fifth metatarsal bones considerably assists to unite them with the tarsus.
The dorsal cubo-metatarsal ligament is composed of fibres which pass obliquely outward and forward from the cuboid to the bases of the fourth and fifth metatarsal bones. They complete the capsule above, and are continuous laterally with the lateral cubo-metatarsal hgament.
The interosseous ligament shuts off the cubo-metatarsal from the middle tarso-metatarsal joint. It is attached to the third cuneiform behind, and to the whole depth of the fourth metatarsal behind its medial facet, and to the apposed surfaces of the third and fourth bones below their articular facets. It is continuous below with the plantar ligament.
tinued between the fourth and fifth metatarsal bones.
Relations. — The line of the tarso-metatarsal joints is crossed dorsally by the tendons of the long and short extensor muscles of the toes and the tendon of the peroneus tertius. On the plantar aspect it is in relation with the obUque adductor of the great toe, the short flexor of the great toe, the lateral plantar artery, and the tendon of the peroneus longus. Its medial end is subcutaneous except that it is crossed, near the plantar surface, by a slip of the tendon of the tibialis anterior, and its lateral end is crossed by the tendon of the peroneus brevis.
The bases of the metatarsal bones are firmly held in position by dorsal, plantar, and interosseous ligaments, supplementing the articular capsules. The first occasionally articulates by means of a distinct facet with the second metatarsal (figs. 245 and 246).
The dorsal ligaments are broad, membranous bands passing between the four lateral toes on their dorsal aspect; but in place of one between the first and second metatarsal bones, a ligament extends from the first cuneiform to the base of the second metatarsal bone.
The movements consist merely of gliding, so as to allow the raising or widening of the transverse arch. Considerable flexibihty and elasticity are thus given to the anterior part of the foot, enabling it to become moulded to the irregularities of the ground.
. of fibres passing transversely from bone to bone, blending witli the fibro-cartilaginous or sesamoid plates of the metatarso-phalangeal joints, and the sheaths of the flexor tendons where they are connected witli the fibro-cartilages. It differs from the corresponding ligament in the hand by having a band from the first to the second metatarsal bone.
These joints are formed by the concave proximal ends of the first phalanges articulating with the rounded heads of the metatarsal bones, and united by articular capsules strengthened by the following ligaments: —
Collateral. Dorsal. Plantar accessory.
The two collateral ligaments are strong bands passing from a ridge on each side of the head of the metatarsal bone to the sides of the proximal end of the first phalanx, and also to the sides of the sesamoid plate which unites the two bones on their plantar surfaces. On the dorsal aspect they are united liy the dorsal ligament.
The dorsal ligament consists of loose fine fibres of areolo-fibrous tissue, extending between the collateral ligaments, thus completing a capsule. It is connected by fine fibres to the \inder surface of the extensor tendons, which pass over and considerably strengthen this portion of the capsule.
The plantar accessory ligament or sesamoid plate helps to deepen the shallow facet of the phalanx for the head of the metatarsal bone, and corresponds to the accessory volar ligament of the fingers. It is firmly connected to the collateral Ugaments and the transverse ligament, and is grooved inferiorly where the flexor tendons pass over it. It serves to prevent dorsal dislocation of the phalanx.
of the median hne, for the sesamoid bones.
(3) The sesamoid bones replace the accessory plantar ligament (sesamoid plate). They are two small hemispherical bones developed in the tendons of the flexor hallucis brevis, convex below, but flat above where they play in grooves on the head of the metatarsal bone; they are united by a strong transverse hgamentous band, which is smooth below and forms part of the channel along which the long flexor tendon plays. They are firmly united to the base of the phalanx by strong short fibres, but to the metatarsal bone they are joined by somewhat looser fibres. At the sides they are connected with the collateral ligaments and the sheath of the flexor tendon. They provide shifting leverage for the flexor hallucis brevis as well as for the flexor hallucis longus.
The movements permitted are: flexion, extension, abduction, adduction, and circumduction.
Flexion is more free than extension, and is limited by the extensor tendons and dorsal ligaments; extension is limited by the flexor tendons, the plantar fibres of the collateral ligaments, and the sesamoid plates. The side-to-side motion is possible from the shape of the bony surfaces, but is very limited, being most marked in the great toe. It is limited by the collateral ligaments and sesamoid plates.
INTERPHALANGEAL JOINTS 311
the bones are smaller and the joints, especially between the second and third phalanges, are often ankylosed. The ligaments which unite them include, in addition to the articular capsule : —
The two collateral ligaments are well marked, and pass on each side of the joints from a little rough depression on the head of the proximal, to a rough border on the side of the base of the distal phalanx of the joint.
The dorsal ligament is thin and membranous, and extends across the joint from one collateral ligament to the other beneath the extensor tendon, with the deep surface of which it is connected and by which it is strengthened.
The accessory plantar ligament covers in the joint on the plantar surface. It is a fibrocartilaginous plate, connected at the sides with the collateral hgaments, and with the bones by short ligamentous fibres; the plantar surface is smooth, and grooved for the flexor tendons.
The only movements permitted at these joints are flexion and extension.
At the interphalangeal joint of the great toe there is very frequently a small sesamoid bone which plays on the plantar surface of the first phalanx, in the same way as the sesamoid bones of the metatarso-phalangeal joint play upon the plantar surface of the head of the metatarsal bone.
Relations of the muscles acting on the metatarso-phalangeal and interphalangeal joints of the foot. — If the student will refer to the accounts given of the relations of the corresponding joints in the hand and of the actions of the muscles upon those joints, and if he contrasts and compares the muscles of the hand with those of the foot, he will readily be able to construct tables of the relations of the metatarso-phalangeal and interphalangeal joints of the foot, and tables of the muscles acting upon the joints.
References. — A complete bibliography for the joints is given in the "Handbuch der Anatomie und Mechanik der Gelenke," by Professor Rudolf Tick (in von Bardeleben's Handbuch der Anatomie). References are also given in the larger works on human anatomy by Quain, Rauber-Kopsch, Poirier-Charpy, etc. References to the most recent literature may be found in Schwalbe's Jahresbericht, the Index Medicus and the various anatomical journals.
MUSCLES, the movements of which are under the control of the will, almost completely envelope the skeletal framework of the body; close in the oral, abdominal, and pelvic cavities; separate the thoracic from the abdominal cavity; surround the pharynx and the upper portion of the cesophagus; and are found connected with the eye, ear, larynx, and other organs. They constitute about two-fifths to three-sevenths of the weight of the body.
In this section an account is given of the gross anatomy of the musculature attached to the skeleton and the skin, with the exception of certain of the muscles which are more conveniently treated in connection with the organs to which they are appended. Thus, the muscles of the eye, the ear, the pharynx, the larynx, and the intrinsic muscles of the tongue are described in the sections devoted to those structures.
Relations to the skin. — Beneath the skin is a sheet of connective tissue, the tela subcutanea. In this, in some regions of the body (the head, neck, and palm), thin, flat, subcutaneous muscles are embedded. Superficial muscles of this kind constitute a panniculus carnosus, much more extensive in the lower mammals than in man. The tela subcutanea is separated from the more deeply seated musculatiu-e by areolar tissue, which, in most places, is loose in texture over the muscles. In some regions, as over the upper part of the back, the tela subcutanea is firmly united to the underlying musculature and is less freely movable. This constitutes the panniculus adiposus, which varies greatly in thickness in different parts of the body. As a rule, it is much more developed over muscles than over those regions where bone and joints lie beneath the skin. From the tela subcutanea of the eyelids, penis, and scrotum fat is absent. The deeper layer of the tela subcutanea is more or less free from fat, and in it run the main trunks of the cutaneous nerves and vessels. In some regions, as over the lower part of the abdomen, one or more fibrous membranes are differentiated in this deeper layer.
To the tela subcutanea the term superficial fascia has been commonly applied, but since this leads to a confusion with the superficial fascia; which immediately invest the muscles, it seems better to restrict the term fascia to the membranes connected with the muscular system, and to use the term tela subcutanea for the layer of connective tissue which underlies the skin and is continuous over the whole surface of the body.
Since the skin and the subcutaneous tissue must be removed in order to study the muscles of various regions, the tela subcutanea and subcutaneous bm-sse may be conveniently described in connection with the muscles, and brief references will, therefore, be made to them in connection with the musculature of various regions.
Muscle fasciae. — The musculature of the body, with the exception of some of the subcutaneous muscles, is ensheathed by fibrous tissue, which, in certain regions forms distinct membranes, while in other regions it is delicate and not clearly to be distinguished from the superficial connective tissue of the muscles, the perimy-
314 THE MUSCULATURE
sium externum. The membranes, or muscle fasciae, are united to various parts of the skeleton, eitlaer directly or by means of intermuscular septa, and, where strong, keep the underlying musculature in place. In some regions they are united to the muscles; in others they are separated from the underlying musculature by loose areolar tissue, which allows free movement between the surface of the muscles and the overlying fascia. The best example of a strong fascia of this nature is that which envelopes the extensor muscles of the thigh. Where the fasciee are well developed, the main bundles of constituent fibres take a course directly or obliquely transverse to the direction of the underlying muscles. They may be composed of several successive layers of fibrous tissue, the fibres of one layer taking a different direction from those of the next layer.
The function of the fascicS is the mechanical one of restraining or modifying muscle action. The direction of the main component fibre-bundles indicates the direction of the greatest stress to which the fascia? are subjected. Indirectly the fasciae promote the circulation of the blood and lymph in places where the vessels lie between the contracting muscles and the overlying fascia.
Intermuscular septa. — Muscle fasciae enclose not only the external layer of the musculature of the body, but also the various groups of more deeply seated muscles. In addition, between the individual muscles, and between the different layers and groups of muscles, there intervenes a greater or less amount of connective tissue, sometimes loose in texture, sometimes dense in structure. In these intermuscular septa run the chief nerves and blood-vessels of the region in which the musculature lies.
Gross structure of the muscles. — The muscles are composed of bundles of reddish fibres surrounded by a greater or less extent of white and glistening connective tissue. They are attached by prolongations of this tissue in the form of tendons or aponeuroses usually to the bony skeleton, but also in places to cartilages, as in the thorax and larynx; to the skin, as in the face; to mucous membranes, as in the tongue and cheeks; to the tendons of other muscles, as in the case of the lumbrical muscles; to muscle fasciae, as in the case of the oblique and transverse muscles of the abdomen; and to other structures, as, for instance, to the eyeball.
The fleshy portion of the muscle is called the belly. The belly is usually attached at one extremity to a portion of the skeleton or to some other structure which serves as a support for its action on the structures to which its other extremity is attached. The attachment to the more fixed part is called the origin of the muscle; the attachment to the structure chiefly acted on is called the insertion. Thus the origin of the biceps muscle, the chief flexor of the forearm at the elbow, is from the scapula; the insertion is into the radius and into the fascia of the forearm. The part of the muscle attached to the origin is called the head of the muscle. The part attached to the insertion is sometimes called the tail, but this term is much less frequently used than the former.
The muscles vary greatly in size and form. Thus the stapedius muscle of the middle ear is a slender little structure, only a few millimetres long, while the gluteus maximus muscle of the hip is a large, rhomboid structure often several centimetres thick and with a surface area of over 500 square centimetres. The length of a muscle from origin to insertion may be much less than the width of the muscle, as in the intercostal muscles; or much greater than the width, as in most of the long muscles of the limbs. The thickness of a muscle is usually less than the width — so much so in some instances that the muscle is described as flat, sheet-like, or ribbon-like; while in other instances the belly is cylindrical. In flat muscles the general outline is usually quadrilateral or triangular. In triangular muscles in most instances one angle of the triangle marks the insertion of the muscle, while the opposite side marks the origin. In cylindrical muscles the belly usually has a somewhat fusiform shape, and grows smaller both toward the origin and the insertion of the muscle.
Some muscles are divided by tendons transverse to the long axis of the muscle. When one such tendon exists, the muscle is called digastric (fig. 348) ; when several, polygastric, e. g., rectus abdominis (fig. 388).
Two muscle masses with separate origins may have a common insertion. Such muscles are usually designated bicipital muscles (biceps muscles of the arm and thigh). Other muscles have three heads (the triceps muscle of the arm) or four (the quadriceps muscle of the thigh). In the latter case special names are given
FINER STRUCTURE OF MUSCLES 315
to the four parts or muscles which constitute the quadriceps as a whole. In addition to these comparatively simple compound muscles there are others in which the various component fasciculi and the tendons of origin and insertion are numerous and complexly interrelated. The intrinsic muscles of the back offer good illustrations of muscles of this nature.
In addition to muscles with distinct regions of origin and insertion, there are a few voluntary muscles which surround hollow viscera or their orifices and have a circular or tube-like form (sphincter muscles, voluntary muscles of the oesophagus, ■etc.).
Number of muscles. — A logical constancy does not appear always to have been followed in the commonly accepted division of the musculature into muscles individually designated. Most of the muscles are symmetrically placed in pairs, one on each side of the body. Authors not only vary in the extent to which they carry the subdivisions of the musculature on each side of the body into individual muscles, but also in describing muscles placed near the median line either as single muscles with bilateral halves or as paired muscles. In addition some muscles are not constantly present, and there are differences of opinion as to which of these less constant muscles should be classed with the normal musculature. The BNA recognises 347 paired and two unpaired skeletal muscles, and 47 paired and two unpaired muscles belonging to the visceral system and organs of special sense. Of the skeletal muscles the head has 25 paired and one unpaired; the neck 16 paired; the back 112 paired; the thorax 52 paired, one unpaired; the abdomen and pelvis 8 paired; the upper extremity, 52 paired; the lower extremity, 62 paired (Eisler).
Finer structure of muscles. — While no attempt can be made here to describe in detail the finer microscopic features of muscle structure, some of the more general features of muscle architecture may be briefly mentioned.
The contractile cells of voluntary muscle are long, slender, multinucleated 'fibres,' the protoplasm of which exhibits both cross and longitudinal striation. The longitudinal striation is due to the presence of fibrils situated in the sarcoplasma. The cross striation is due to alternate segments of singly and doubly refracting substance in these fibrils. The length of these fibres in the human body varies from a few millimetres to sixteen centimetres or more, and the thickness from ten to eighty microns. Each muscle-fibre is surrounded by an especially differentiated sheath, the sarcolemma. Outside of this is a layer of delicate connective tissue, the perimysium internum or endomysium, the fibres of which are in part inserted into the sarcolemma. This connective tissue, which is especially developed at the ends of the fibres, serves to .attach them either directly to the structures on which the muscle acts or to the skeletal framework of the muscle.
In the simplest mammalian muscles the muscle-fibres take a parallel course from tendon to tendon, and are not definitely bound into secondary groups. An example may be seen in fig. 338, a, which represents two segments of the rectus abdominis muscle of a mouse. More often, however, the individual fibres do not run the entu-e distance from tendon to tendon, but instead . they interdigitate, and the interdigitating fibres are bound up into secondary and tertiary anastomosing fibre-bundles by connective tissue, in which there is usually a considerable amount of elastic tissue. Fig. 338, b, represents diagrammatically this interdigitation of fibre-bundles as seen in the abdominal musculature of one of the larger mammals.
In most of the flat muscles of the body the fibre-bundles either take a nearly parallel course from tendon to tendon or they converge from the tendon of origin toward the tendon of insertion (see fig. 338, c-e). The gi-eater the distance from tendon to tendon, the more marked is the interdigitation of the constituent fibre-bundles.
In elongated muscles the tendons of origin and insertion may either arise near the extremities of the muscle or may extend for a considerable distance on the surface or within the substance of the muscle. In the former case the belly of the muscle is composed of bundles of interdigitating fibres which take a course parallel with the long axis of the muscle. This is shown diagi'ammatically in fig. 338, f. An example may be seen in the sartorius muscle of the thigh (fig. 411). When the tendons extend far on the surface or within the substance of the muscle, the constituent fibre-bundles take a course oblique to the long axis of the muscle. When they take a course from a tendon of origin on one side toward a tendon of insertion on the other, the muscle is called unipenniform (see fig. 338, g, and the extensor digitorum longus, fig. 415). In other instances the fibre-bundles converge from two sides toward a central tendon. Such a muscle is called bipenniform (see fig. 338, h, and the flexor hallucis longus, fig. 416). When there are several tendons in the muscle between which the fibre-bundles run obliquely, the muscle is called multipenniform. In fusiform muscles the tendons usually either embrace the extremity of the muscle like a hollow cone, or they extend far on the surface or within the substance of the muscle. In such muscles the fibre-bundles take a curved course from one tendon to the other. The bundles which arise highest on one tendon are inserted highest on the other, and the fibre-bundles of lowest origin have the lowest insertion. This structm-e is diagrammatically shown in fig. 338, i. A good example may be found in the rectus femoris muscle (fig. 411).
more complex muscles dense connective-tissue septa, or intramuscular fasciae, serve to separate different regions of the muscle from one another. In general there are groups of muscle fibrebundles surrounded by a greater amount of connective tissue, or perimysium internum, than that surrounding the individual fibre-bundles, and the latter are surrounded by a denser connective
a. Two segments of the rectus abdominis muscle of a small mammal, b. Portion of sheet-like muscle with two nerve-branches and intramuscular nerve plexus, c. Typical quadrilateral muscle with nerve passing across the muscle about midway between the tendons, d and e. Two triangular muscles with different types of innervation, f. Long ribbon-like muscle with interdigitating fibre-bundles, g. Unipenniforra muscle, h. Bipenniform muscle, i. Typical fusiform muscle. The main intramuscular nerve-branches are distributed to the fibre-bundles about midway between their origins and insertions, n. nerve.
tissue than that surrounding the component muscle-fibres. The muscles are surrounded externally by a more or less dense sheet of connective tissue called the perimysium externum, or epimysium, which is continuous with the connective tissue within the muscle, the perimysium internum. In the following pages 'muscle fibre-bundle' is used to denote small groups of muscle-fibres, 'fasciculus' to denote large, more or less isolated, groups of fibre-bundles.
Embryonic development of muscles. — The voluntary muscles are of mesodermal origin. The muscles of the trunk arise chiefly from the myotomes, those of the head and limbs chiefly from the mesenchyme in these regions. New muscle fibres are formed mainly before birth. After birth, growth of muscles depends on growth of individual muscle fibres.
TENDONS 317
Tendons. — Muscles vary not only in general form and in the relations of the constituent fibre-bundles to the intrinsic skeletal framework, but also in the mode of attachment to the parts on which they act. In many instances the fibre-bundles impinge, perpendicularly or obliquely, directly upon a bone or cartilage. The tendinous tissue arising from the fibre-bundles of the muscle here is attached to the periosteum or perichondrium or to the bone directly. A broad attachment is thus offered the muscle. Instances of this mode of attachment may be seen in the attachment of the intercostal muscles and of many of the muscles attached to the shoulder and hip girdles.
In the case of most thin, flat muscles the muscle is continued at one or both extremities into thin, tendinous sheets called aponeuroses, composed of connective tissue. Well-marked instances may be seen in the transverse muscle of the abdomen (fig. 390), and the trapezius and latissimus dorsi muscles of the back (fig. 355) . The extent of development of these aponeuroses is generally inversely proportional to the development of the muscle — the more extensively developed the muscle is in a given individual, the less extensive the aponeurotic sheet.*
Most muscles are continue,d at one or both extremities into dense, tendinous bands which may be comparatively short and thick, like the tendon of Achilles (fig. 413) , or very long and narrow, like the tendon of the palmaris longus (fig. 370) . In this latter case the tendon represents in part the remnants of musculattu-e more highly developed in the lower vertebrates. In most instances, however, the tendons are structures specifically differentiated for definite functions and are composed of bundles of parallel connective-tissue fibrils held together by an interlacing fibrous-tissue framework. The tendons usually contain a relatively small amount of elastic tissue.
the bone and ossified.
In some tendons sesamoid bones are developed in the neighbourhood of joints over which the tendons pass. Examples of these are the patella at the knee-joint (fig. 412) and the sesamoid bones of the thumb and great toe.
Where muscles or tendons closely envelope a joint, there is usually formed a close union between the connective tissue of the capsule of the joint and that of the muscle or the tendon. Special bands may develop in the direction of the pull of the muscle (lig. popliteum obhquum).
Where tendons run for some distance across or beneath a fascia, they are usually either bound to the fascia by a special investment, as near the wrist and knee (fig. 366 and fig. 414), or are fused with the fascia, as in the case of the iliotibial band. Fibrous tracts in the fascia may indicate stress under muscle contraction (the lacertus fibrosus of the fascia of the forearm) .
Often in broad aponeurotic attachments of muscles there is formed in the tendon near the attachment a fibrous archway [arcus tendineus] for the passage of blood-vessels, nerves, muscles, or tendons. The tendinous arch is either fastened at both ends to the bone, or at one end it is connected with'a joint capsule or other membrane. The dorsal attachment of the diaphragm (fig. 391) and that of the adductor magnus to the femur (fig. 409) offer good examples of tendon arches.
In digastric and polygastric muscles the transverse tendons which separate the bellies are often composed of narrow, incomplete bands of fibrous tissue. Such a transverse band is called an inscriptio tendinea (see Rectus Abdominis Muscle, fig. 388).
Tendon sheaths. — The tendons are held in place by sheaths composed of dense connective tissue. These sheaths vary in different regions. In the most complete form they confine tendons in osseous grooves which they convert into osteofibrous canals on the flexor surface of the digits. It is strengthened by tendinous bands (vaginal ligaments). In other regions special dense bands or ligaments, retinacula tendinum, confine a series of tendons in place, as at the ankle (fig. 417), or fasciae may be modified for this purpose, as at the back of the wrist (fig. 366) . A tendinous loop,
* The terms fascia and aponeurosis are often loosely and interchangeably used. It seems best to make a distinction by restricting the term fascia to membranous sheets of investment, and aponeurosis to broad tendons. The latter may, however, be inserted into and form a part of the former.
tendon of the superior oblique muscle of the eye.
Synovial bursas [bursae mucosae]. — Where there is freedom of action between muscles and tendons and the surrounding parts, there intervenes a loose connective tissue. In regions where the pressure is great or considerable friction would result were these conditions retained, there are developed special cavities with smooth surfaces and containing fluid. Most of these bursas are developed from the intervening connective tissue at a period in embryonic life preceding muscular activity, but special bursas may later be developed as the result of unusual pressure or muscular activity after birth. An instance of a bursa lying in a region of friction may be seen in the bur?a intervening between the tendinous posterior surface of the ilio-psoas muscle and the ilio-femoral ligament. As an instance of a bursa lying in a region of intermittent pressure may be cited that between the tendon of Achilles and the calcaneus.
Most synovial burste intervene between a tendon and a bone, a tendon and a ligament, or between two tendons (subtendinous bursse mucosae). Others lie between two muscles, a muscle and some skeletal part, or between a muscle and a tendon (submuscular bursae mucosae) ; or below a fascia (subfascial bursae mucosas). Subcutaneous bm-sse have been referred to in connection with the tela subcutanea (see p. 313). Most bursas are developed near joints. The bursae may so expand during active life that they come to communicate with other bursae or with a neighbouring joint cavity.
Synovial sheaths [vaginae mucosae tendinum]. — Synovial sheaths are developed about tendons where the latter are confined in osteo-fibrous canals, as in the fingers. The wall of the canal and the enclosed tendon, or tendons, are each covered by a smooth membrane which at the extremities of the canal is reflected from the wall to the tendon. Between the membrane covering the tendon and that lining the canal is a sjaiovial cavity. An interesting feature of these tendonsheaths is the presence of mesotendons, delicate bands of vascular connective tissue which run in places from the osseous groove to the tendon and carrj^ bloodvessels and nerves.
Trochlese. — Where a tendon passes at an angle about a bone, the tissue in the groove in which the tendon runs frequently is composed of hj'aUne cartilage instead of bone. An example may be seen in the trochlear process of the calcaneus.
Nerves. — To each muscle of the body a nerve containing motor and sensory fibres is distributed. A few muscles receive two or more nerves. Sherrington has estimated that in the muscle-nerves of the cat two-fifths of the fibres are sensory and thi-ee-fifths motor.
The muscles of the liead and in part those of the neck are supplied by branches of the cranial nerves. The intrinsic muscles of the neck, back, thorax, and abdomen are supplied by branches which arise fairljr directty from the spinal nerves. The muscles of the limbs are supplied by branches from nerve-trunks which arise from plexuses formed by the spinal nerves in the regions near which the limbs are attached.
The main nerve-trunks lie beneath the superficial muscles. They usually run in the intermuscular septa which separate the deeper groups of muscles from one another and from the superficial muscles. The nerve-branches which enter a given muscle usually pass in where the larger intramuscular septa approach the surface of the muscle, and then ramify tlu-ough the perimysium internum, the smaller branches being distributed in the finer layers of connective tissue which surround and separate the primary muscle fibre-bundles, to the constituent musclefibres of which terminal branches are given. Special sensory end organs are distributed chiefly in the large intramuscular septa, in the tendons and in the muscles near the tendons. Simple sensory endings are found on the muscle fibres.
rather to the comple.xity of movements in which the muscle plays a part.
Muscles receive then- nerve supply early in development. During later development the muscle may wander a considerable distance from its place of origin and carry its nerve with it. The diaphragm, innervated by cervical nerves, is a good example.
The distribution of the motor nerves varies according to the architectm-e of the muscle, but in general it appears that the nerves are so distributed as to carry the main branches of distribution most directly to the middle of the constituent fibre-bundles. This is seen most clearly in muscles with comparatively short fibre-bundles, where the individual muscle-fibres run nearly or quite the entire distance from tendon to tendon (fig. 338 a, c, d, e, g, h, and i). When the distance is long, a marked plexiform arrangement is found (fig'. 338, b andf). To each muscle
Vessels. — The muscles are richly supplied with blood. In many instances the larger blood-vessels accompany the larger nerve-trunks as they enter the muscle, and their primary branches are distributed in the larger intramuscular septa. Often, however, the main blood-vessels approach a muscle from a direction different from that taken by the nerves. Each muscle has, however, its own blood supply. There is little anastomosis between the blood-vessels of a muscle and those of a neighbouring structure, but the anastomosis between the vessels within the muscle is exceedingly rich. Veins, as a rule, accompany all but the smallest arteries within the muscle. The veins are richly supplied with valves, so that muscle contraction promotes the flow of blood through the muscle. Rich capillary plexuses sm-round the muscle-fibres. The capillaries are of unusually small diameter.
During contraction, the blood is forced from the muscles; during expansion it rushes in through dilated arteries which furnish five or six times as much blood to muscles during exercise as that supplied to them during rest.
The connective-tissue sheaths, the larger intramuscular septa, and the tendons of muscles are richly supplied vnih. lymphatics. There are no lymphatics within the muscle bundles or in small muscles.
Nomenclature. — The names of the various muscles and their classification are less satisfactory than is desirable. The muscular system was first carefully studied in the human body, and names based sometimes upon the shape, structure, size, or position, at other times upon the supposed function or other associated facts, were applied to the muscles found in various regions. Sometimes two or more names were applied to a muscle to indicate several of these factors. Thus trapezius and triangularis indicate the shape of the corresponding muscles; biceps or triceps indicates the origin by two or three heads; rectus, obliquus, and iransversus represent the direction taken by a muscle or its constituent fibre-bundles; viagnus and minimus indicate size; sublimis (superficial) and profundus (deep) represent the relative positions occupied; sterno-cleido-mastoid indicates structures to which the muscle is attached; flexor and extensor indicate function; and sartorius indicates that the corresponding muscle was supposed to be of use to tailors.
Since careful study has been devoted to the comparative anatomy of the muscles in various vertebrates, it has become apparent that a simple and more consistent nomenclature applicable to corresponding muscles found in various animals would be of great value. A satisfactory nomenclature of this sort has not, however, as yet been devised and adopted in comparative anatomy, and the established usage of the terms now familiarly apphed to the muscles of the human body makes it seem improbable that even if such a system were devised for comparative anatomy it could be brought into extensive use in human anatomy. For many of the muscles in the human body various synonyms have been in use in different countries. The Anatomical Congress assembled at Basel in 1895, to simpUf}' the nomenclature of human anatomy, adopted in large part the terms in familiar use in England and America. In the following pages the terms approved by the Congress wiU be employed, but where they differ materially from those previously in use, the synonym wUl be given in parentheses.
Classification. — The muscles are usually treated strictly according to the region of the body in which they are found. This method of consideration is still of value in a dissector's guide and in text-books of topographical anatomy. But in studying the muscles scientifically it is of importance also to consider them in their more fundamental genetic relationships to one another and to the nervous system. Embryology and comparative anatomy have proved of the greatest value in revealing these relationships. Studies of this nature have revealed well-marked relationships in the adult human musculature which are of practical as well as scientific importance The voluntary musculature may be broadly divided into that of the skeletal axis, the limbs, and the visceral orifices. The musculature of each of these divisions has a different and in general simpler form in the lower than in the higher vertebrates, and in the embryos of the higher vertebrates than in the adult. The musculature of the spinal region of the body axis of fishes, the tailed amphibia, and all vertebrate embryos is metamerically segmented; that is, it is divided along the axis of the body into a series of components corresponding with the segmentation of the vertebral column. Although marked alterations take place in the subsequent ontogenetic differentiation in higher vertebrates, traces of this primitive segmentation are still to be found in the adult; in man, for instance, in the intercostal muscles and the segments of the rectus abdominis. In the region of the head conditions are complex, owing to the concurrent presence of muscles which primitively correspond in nature with the segmental spinal musculature, and muscles non-segmental in character, which surround the visceral orfices. This also is true of the anus and external genitalia, where, however, the conditions are simpler. Embrj'ology and comparative anatomy have done much to clear up puzzling features in both regions.
Where mammalian musculature is primitively segmental, each segment becomes associated with a corresponding spinal nerve or, in the head, with a nerve which corresponds in series with a spinal nerve. Even when subsequent differentiation brings about marlied alterations in the axial musculature, the nerves maintain to a considerable degree a segmental distribution.
Into each of the limbs, where the intrinsic musculature is at no time segmental, there extends during embryonic development a series of segmental spinal nerves, so that in them, as in the region of the body axis, a certain segmentation in the nerve-supply can be made out in the adult. That part of the limb nearest the head in early embryonic development has its muscles supplied by the most cranial, that part nearest the caudal extremity of the body by the most caudal, of the nerves which supply the hmb musculature. There is here, however, considerable overlapping of the segmental areas.
Variation. — In man some variation in the arrangement of the muscles is met with in every individual, and often marked deviations from the normal conditions are found. The muscles vary in their mode of origin or insertion, and in the extent to which muscles of a given group are fused with one another or to which the chief parts of a complex muscle are isolated from one another. Some muscles, like the palmaris longus and the plantaris, are frequently entirely absent, and other muscles generally absent are frequently present.
In addition to these frequent variations there are others so rare that many authors prefer to speak of them as anomalies rather than variations. Sometimes muscles may be found doubled by longitudinal division, or two or more muscles normally present may be fused into a single indivisible muscle. Occasionally there occur muscles constantly present in some of the lower animals, but normally not met with in the human body (anomalies of reversion or of convergence). In such instances the muscle may be normally represented by a tendon or fascia. At times the anomalies are supposed to be not a reversion to an ancestral condition, but a distinct step in advance. This, however, is difficult to prove. At other times no phylogenetic relation is apparent, and the anomaly is looked upon as a monstrous sport or as the result of somepathological condition.
supply of the muscles.
Physiology. — From the standpoint of morphology the muscles are grouped according to their intimate relations to one another and to the peripheral nerves, relations, as noted above, that are made more clear by a study of comparative anatomy and embryology. From the physiological aspect a different grouping of the muscles is required, because muscles belonging morphologically in one group may have different physiological functions in the animal body. The chief features of the mechanical action of muscles may be briefly considered here.
Most muscles act on the bones as levers. In physics three types of levers are recognised In levers of the first type (fig. 339, I) the fulcrum (F) lies between the place where power (P) is exerted on the lever and the point of resistance or load (L) . Levers of this kind are frequently met with in the body. A good example is seen in the attachment of the skull to the vertebral column. The fulcrum lies at the region of attachment; the weight of the skull tends to bend the head forward, while the force exerted by the dorsal muscles of the neck serve to keep the head upright or to bend it back.
In levers of the second class (fig. 339 II) the point on which power is exerted moves through a greater distance than the point of resistance. Speed of movement is thus sacrificed to power. Levers of this type are exceedingly rare in the animal body. An example in the human body is the foot when the body is raised on the toes.
In levers of the third class (fig. 339, III) the point on which force is exerted moves a less distance than the point of resistance. Power is thus sacrificed to speed. This is the common form of leverage found in the body. A good example is found in the action of the muscles which flex the forearm on the arm. The region in which the biceps and brachialis are attached is but a short distance from the elbow-joint or fulcrum, while the hand may be looked upon as the region of resistance to the force exerted. A movement of the point P through a short distance will cause L to move through a great distance.
The more the angle between a muscle or its tendon and the bone on which it acts approaches a right angle, the greater is the power of movement exerted by the muscle. The arm in fig. 339, III, is in the position of greatest advantage for the action of the biceps on the forearm. All boys know that it is easier to 'chin' oneself after the arm is partly bent than when hanging
PHYSIOLOGY
straight from a bar. Many of the muscles run nearly parallel with the parts on which they act, but the tendons before their attachment are usually either carried over a bony prominence or some fascia or hgament acts as a pulley so that tlie tendon is inserted at an oblique angle. At other times a process for the attachment of the tendon projects from the bone and causes the force of the contracting muscle to be more advantageously exerted on the bone. It may, of course, readily be seen that the greater the distance of the attachment of a muscle from the joint over which it acts, the greater will be the power exerted by the muscle.
In considering the movements of the body, it is convenient to recognise two groups, simple and complex. To the former, which alone can be considered in a text-book of anatomy, belong such movements as flexion, extension, adduction, rotation, etc., while to the latter belong those associated movements which give rise to changes in the positions of the body as a whole or of extensive regions of the body.
In flexion the extremities of the trunk or limbs or special portions of these regions are bent near to one another; in extension the reverse movement is brought about. The parts are straightened or even bent beyond the straight position (over-extension).
brought about.
In rotation a part is turned on its longitudinal axis. The rotation of the femur at the hip-joint is called medial rotation when the toes are turned medialward, lateral rotation when the toes are turned lateralward. Rotation at the shoulder-joint is called medial when the thumb is turned forward and medialward toward the body, lateral when the reverse movement takes place. These movements are also carried out at the elbow-joint, but here medial rotation is called pronation, lateral rotation, supination. Fick prefers these terms also for the rotation at other joints as at the shoulder, hip and knee.
At the shoulder- joint the swinging of the arm toward the back is called extension; toward the front, flexion; and from the side, abduction. Moving the arm toward the mid-dorsal or mid-ventral line is called adduction.
Taking the body as a whole the musculature may be divided into two main divisions, an ex-pander division and a, contractor division. In general the extensors, abductors and lateral rotators expand, the flexors, adductors and medial rotators contract.
In the most expanded condition the head and spine are extended or even sUghtly hyperextended (flexed dorsally), and the limbs project laterally from the body with the backs of the hands and feet facing dorsalward, the palms and soles ventral ward, and the digits spread out. In the fully formed human body it is not possible to put the lower extremity in the completely expanded position, although it is in this position early in embryonic development. As development proceeds the lower extremity is adducted and rotated medialward and the girdle is so fixed that full abduction becomes no longer possible. In many of the lower vertebrates full abduction is possible throughout life in the lower extremities just as it is throughout life in the upper extremities in man. Full extension of the spinal column in man is also hindered in the thoracic region by the thorax, and in the sacro-coccygeal region by the osseous union of the vertebrae with one another as well as by the attachment of the hip girdles. The lumbar region in man is in a condition of permanent hyper-extension.
In the fully contracted condition the head and spinal column are strongly flexed, and the digits are adducted, the various segments of the Hmbs are flexed and the Umbs are adducted, flexed and rotated medialward toward the middle of the trunk. The body approaches a ball in form. It is the position taken by a gymnast when turning a somerset in the air, and is in marked contrast to the fuUy expanded condition which would be assumed could man fly Mke a bat or glide Uke a flying squirrel.
In general, the muscles which tend to put the body or a part of the body into the expanded position form a distinct group as contrasted with those which tend to put the body into the contracted position. The chief musculature which extends the head and trunk lies dorso-lateral to the spinal column and is supplied by the dorsal divisions of the spinal nerves. The chief musculature which flexes the head and trunk lies ventro-lateral to the spinal column and is supplied by ventro-lateral divisions of the spinal nerves. The chief muscles which abduct, extend and rotate the limbs lateralward arise during embryonic development on the dorsal sides of the limb buds and are innervated by branches from the dorsal sides of the brachial and lumbo-sacral nerve plexus. The chief muscles which flex, adduct and rotate the Hmbs medialward arise on the ventral sides of the Umb buds and are supphed by nerves which arise from the ventral sides of the hmb plexuses. To these general rules there are some exceptions, the most marked of which is at the hip-joint where rotation of the girdle has brought about a condition in which the primitive action of the flexor and extensor groups is partly reversed. The chief flexors (the ilio-psoas and rectus femoris) belong to the dorsal division and some of the chief extensors (the hamstring muscles) belong to the ventral division. At the ankle-joint the exception is more apparent than real. What is usually called flexion at the ankle-joint is really hyper-extension and the reverse movement is the nearest we can come to real flexion. In the extremelj' contracted position of the body as a whole the feet are extended (flexed plantarward) at the ankle-joint.
Muscles which produce a movement in a common direction are called S3aiergists, while those whose contraction produces opposite movements are called antagonists; e. g., the flexors and extensors are antagonists. In the actual working of the muscular system, however, when a set of muscles is contracting to produce a movement, the antagonists also contract to a .;ertain degree. The movement is the result of nerve /^impulses^ sent simultaneously to all the muscles which act on the part moved. |
The relation of the internal architecture of a muscle to the movements to which its contraction gives rise is a complex subject, the details of which cannot be entered into here. In general it may be said that when the fibre-bundles run directly from one attachment to the other, as in fig. 338, a and f, the force exerted by the contraction of the individual muscle-fibres is most efficiently utilised and the extent of the movement varies directly as the length of the fibres, while the force exerted varies directly with the number of the fibres.
In muscles of the types indicated in fig. 338, g, h, i, a certain amount of the extent of movement and of the force exerted by the contraction of the individual fibres is not effectively exerted on the parts moved by the muscles, as may be seen by applying to this action the laws of the parallelogram of forces. In such muscles, however, the great number of short musclefibres composing them makes possible the exertion of great power with some loss of speed of contraction in the muscle as a whole.
The direction of the movements which result from muscular contraction is in large part determined by the shape of the articular surfaces, none of which are to be looked upon as simple fulcra, but instead, during a given movement, the fulcrum shifts from one region to another of the joint.
In different muscles the extent of contraction of the constituent fibre-bundles during activity varies considerably. While usually the length of the contracted fibre-bundles is half that of those in the extended state, the amount of shortening in some muscles is only 25 to 35 per cent.
prevented from contracting.
Order of treatment. — The muscles and fascia are here treated in the following order : — (1) those of the head and neck and shoulder girdle (p. 323) ; (2) those of the upper extremity (p. 360); (3) those of the back (p. 410); (4) those of the thorax and abdomen (p. 422); (5) those of the pelvic outlet (p. 439); (6) those of the lower extremity (p. 452). The reason for taking up the musculature in the order named is, that during embryonic development musculature belonging primitively to the head comes to overlap that of the neck; that of the neck spreads over the region of the back and thorax, and becomes attached to the shoulder girdle; that of the arm extends over the region of the thorax, abdomen, and back; that of the back partially over the region of the thorax; while that of the abdomen enters into intimate relation with the pelvic girdle. So far as practicable the musculature of these various regions will be taken up according to fundamental morphological relationships.
Since a morphological grouping of the muscles does not accord perfectly with a physiological grouping, there is given at the end of this section a table showing what muscles are concerned in performing the simpler voluntary movements.
PHYSIOLOGICAL AND MORPHOLOGICAL ASPECTS
The head, situated at the anterior end of the trunk in bilaterally symmetrical animals, is primitively that part of the body first brought into contact with new surroundings as the animal moves forward. We therefore find developed here the most highly differentiated organs of .special sense, those of vision, hearing, and smell, through which the animal is put in touch with an environment more or less removed from immediate contact with the body. In connection with these
organs of special sense, the brain is developed. In most animals the head also is the chief organ for the prehension of food and for attack and defense. The neck is a part of the trunk differentiated to give freedom to the movements of the head. The forelimbs, relatively unimportant as the forefins in the fishes, become important organs of locomotion in the land animals. In the fishes there is no true neck, but the forefins are developed at the sides of the cervical part of the trunk. In the higher vertebrates the forelimbs are also first differentiated at the sides of the cervical region (fig. 340) but, as embryonic development goes on, they shift caudalward to the sides of the cranial (anterior) part of the thorax. The cervical region is thus left free for movement but the musculature and nerves of the upper extremity remain intimately related to it.
In man, with the assumption of the erect posture, the head no longer has to bear the brunt of the new surroundings as the body moves forward. There is, however, a distinct advantage in having those organs of special sense, which put the individual into touch with the more distant parts of the environment, situated high above the ground, and a motile neck is of great value in directing the organs of special sense toward various parts of the environment. The development of the superior extremities as organs for the prehension of food and as organs of attack and defense reduces the value of the head for these purposes, but still leaves it the important functions of the reception of food and air and the preparation of food for gastric and intestinal digestion. The head, furthermore, assumes a new and most important function as an organ for the expression of the emotions and of speech.
The expression of the emotions, such as anger, fear, affection and the like,* is brought about largely through the action of flat, subcutaneous "facialis" muscles which underlie most of the skin of the face and head and extend down under that of the neck (figs. 341 and 344). They also line the mucous membrane of the lips and cheeks. Most of them arise from the surface of the skull and are inserted into the skin, which they pull in various directions causing it to become smooth or twinkled, according to the direction of the pull. The various muscles are grouped about the buccal, nasal and aural orifices and about the orbit of the eye. Some of the fibre-bundles are arranged so as to constrict the orifices, others radiate out so as to dilate them.
The chief groups of muscles of the head and neck, in addition to the facialis group just mentioned, are the muscles of the orbit and middle ear, the muscles used in mastication and swallowing (cranio-mandibular, supra- and infrahyoid groups, muscles of the tongue, soft palate and pharj^nx), the muscles of the larynx, and the ventral and dorsal groups of muscles which lie in the region of neck, extend over the thorax and move the head, neck and shoulder girdle. A brief summary of these groups will be given before proceeding to a more detailed account.
Facialis group. — The muscles are especially well developed about the mouth, a sphincter muscle {orbicularis oris) serving to close, the radiating muscles to open the lips {quadratus labii superioris and inferioris), to pull the corners ot the mouth in various directions, as, for instance, upward to express bitterness {caninus) or pleasure {zygomaticus) , or lateralward and downward to express grief or pain (risorius, triangularis, plalysma) or to protrude the lips as in pouting {mentalis and incisive muscles). The buccinator, which radiates out from the corner of the mouth and hues the mucous membrane of the cheek, is used in mastication and whisthng.
About the orbit and in the eyelids a circulai- musculature {orbicularis oculi) is broadly developed. It is usedto close the eyes, and to contract the skin about the orbit. Associated with the orbicularis are muscles which produce perpendicular furrows in the skin of the forehead above the nose (procerus, corrugator). The skin is drawn upward from the orbit and horizontal furrows are caused in the skin ot the forehead by muscles attached to the scalp (epicranius). Two of these muscles, the occipitales, arise one on each side from the occipital bone and are attached to an aponeurosis which lies beneath the scalp to which it is firmly united. Two of the muscles, the frontales, extend one on each side from this aponein-osis to the skin above the eyebrows.
About the nasal orifices there are weak constrictors (alar part of the nasalis, depressor aloe nasi) and dilators (dilator naris anterior and posterior, transverse part of the nasalis, angular head of the quadratus labii superioris). From the ear (auricle) three flat muscles radiate, one backward (auricularis posterior), one upward (auricularis superior) and one forward (auricularis anterior). These muscles are seldom functionally developed. They pull the auricle in their respective directions. They may be looked upon as (primitively) dilators of the aural orifice. On the cartilage of the auricle are several rudimentary " intrinsic " muscles which may be looked upon as remnants of a constrictor of this orifice.
GROUPS OF MUSCLES 325
In the orbital cavity there are six muscles which are attached to and move the eyeball and one muscle (the levator palpehroe superioris) which extends into and raises the upper lid (fig. 341) . Of the muscles which move the eyebaU five arise hke the levator of the lid, from the back of the orbit. Four of these, the rectus muscles, are inserted respectively into the superior, inferior, medial and lateral sides of the eyeball and direct the pupil upward, downward, medialward and lateralward. One, the superior oblique, sends a tendon through a loop at the upper, front part of the nasal side of the orbit and thence to the upper surface of the eyeball. Another muscle, the mferior oblique, arises from the nasal side of the front of the lower part of the orbit and is attached to the lower part of the eyebaU. The obUque muscles prevent the rectus muscles from rotating the eyeball. These muscles are supphed by the third, fourth and sixth cranial nerves. They are described in the section on the eye, p. 1067. In the middle ear are two small muscles (the tensor tympani and the stapedius) attached respectively to the malleus and stapes and supplied by fifth and seventh cranial nerves. They are described in the section on the ear, p. 1091.
Mastication and swallowing. — The complex musculature used in biting, masticating and swallowing food is used also in speech in conjunction with the muscles of the larynx and the lips. The two movable bones of the skull concerned with these functions are the mandible and the hyoid bone. The mandible articulates with the skull on each side, just in front of the external auditory meatus. The hyoid bone is connected on each side by the stylo-hyoid ligament with the styloid process of the temporal bone, which descends just behind the external auditory meatus. A powerful group of muscles, the cranio -mandibular muscles (figs. 344, 345, 346, 347 c), or muscles of mastication, arise from the temporal fossa {temporal muscle), the zygomatic arch [masseter muscle) and the pterygoid process (external and internal pterygoid muscles) and are inserted into the coronoid process of the mandible [temporal muscle), the outer side of the ramus {masseter muscle), the inner side of the ramus {internal pterygoid), and into the condyle of the jaw {external pterygoid). These muscles raise the jaw, move it forward and from side to side, and are used in biting and chewing the food. They are innervated by the fifth cranial (masticator) nerve.
Another less powerful group of muscles, the suprahyoid group (fig. 348), is divisible into two subdivisions, hyo-mandibular which extends in front between the hyoid bone and the ramus of the jaw (anterior belly of the digastric, genio-hyoid, mylo-hyoid) and a hyo-temporal group which extends between the hyoid bone and the temporal bone back of the external auditory meatus {stylo-hyoid, posterior belly of the digastric). Two of the hyo-mandibular muscles (the anterior belly of the digastric and the mylo-hyoid) are innervated by the trigeminal; the genio-hyoid by the hypoglossal nerve. The two hyo-temporal muscles (posterior belly of the digastric and stylo-hyoid) are innervated by the facial nerve. Morphologically therefore, as indicated by this innervation, the muscles of this group are diverse. Physiologically they are closely united. The group, acting as a whole, elevates the hyoid bone and with this the larynx and the tongue. If, however, the hyoid bone be fixed by contraction of the neck muscles (infrahyoid muscles) attached to its lower border, the suprahyoid muscles act as antagonists of the cranio-mandibular muscles and depress the jaw. The hyo-mandibular muscles form, together with the tongue, the muscular floor of the mouth. When acting with the hyo-temporal muscles they help the tongue to pass food into the pharynx. When acting alone the hyo-mandibular muscles draw forward the hyoid bone and with it the base of the tongue and the larynx and thus open the passage from the pharynx into the oesophagus. The two hyo-temporal muscles, acting in conjunction with the middle and inferior constrictors of the pharynx, draw the hyoid bone and larynx backward, as well as upward, and thus constrict the pharynx while giving free passa'_e for air from the naso-pharynx into the larynx. The chief functions of the suprahyoid group are, therefore, to play a part in deglutition and respiration. Closely associated with the muscles of the suprahyoid group in the performance of these important functions are the muscles of the tongue, the pharynx and the soft palate. The bulk of the tongue (fig. 349) is made up of muscles which have their origin on each side from the inner surface of the front part of the mandible {genio-glossus) , the hyoid bone {hyo-glossus and chondro-glossus) and the styloid process of the temporal bone {stylo-glossus) . Muscles also connect the tongue with the palate (glosso-palatinus) and with the pharynx {glosso-pharyngeus). These muscles, together with intrinsic longitudinal, transverse and perpendicular fibre-bundles, enable the tongue to perform the complex activities associated with mastication and swallowing and with speech. During mastication the tongue passes the food from side to side between the teeth. When the food has been masticated the tongue forms a bolus of it and then this is passed into the pharynx by a sudden elevation of the dorsum of the tongue produced in part by the muscles of the tongue, in part by the suprahyoid group of muscles. The muscles of the tongue are described on p. 345.
The pharynx is the dilated upper part of the alimentary canal into which open the Eustachian tubes, the nasal passages, the mouth and the larynx. The walls of the side and back of the pharynx are composed mainly of muscular tissue. The chief muscles are three " constrictor " muscles on each side, a superior, a middle and an inferior, and an elevator and dilator, the stylO'pharyngeus (fig. 894). The three constrictor muscles are attached to the median raphe* which extends in front of the spinal column from the base of the occipital bone to the sixth cervical vertebra. The superior constrictor muscle is attached to the pterygoid process, the pterygo-mandibular ligament, the mandible and the side of the root of the tongue (fig. 343) ; the middle constrictor to the hyoid bone ; and the inferior constrictor to the larynx. These muscles constrict the pharyngeal orifice and thus force food into the oesophagus. The stylo-pharyngeal muscle, which extends from the styloid process into the lateral wall of the pharynx, serves to
* The attachments to the raphe are usually spoken of as the insertions, those to the bones in front as the origins of these muscles. The raphe is, however, a more fixed structure than most of the structm'es to which the constrictors are attached in front.
scribed on page 1134.
The orifices of the various passages into the pharynx are dilated or constricted by muscular action. The orifices of the nasal passages, the Eustachian tubes, and the mouth are controlled mainly by the musculature of the soft palate and pharynx. The orifice of the larynx is controlled by special muscles which act in conjunction with those of the suprahyoid group, the tongue, and the pharynx.
The soft palate is a muscular partition which is continued backward from the hard palate between the buccal cavity and the naso-pharyngeal orifice and then bends downward between the back part of the mouth and the nasal part of the pharynx, terminating in a median projection, the uvula. Above, on each side, back of the fold of tissue {plica salpingo-palatinus) which descends from the ventral border of the orifice of the Eustachian tube and which marks laterally the passage from the nose into the pharynx, there is a muscle,- the levator veli palatini (fig. 343~>. This arises from the petrous portion of the temporal bone and from the Eustachian tube descends to the middle of the side of the soft palate and then spreads out broadly on its dorsal side. The muscle from each side interdigitates to some extent with that of the other side. These muscles raise the soft palate toward the upper part of the posterior wall of the nasopharynx and thus shut off the nose from the buccal portion of the pharynx during deglutition. The sides of this portion of the pharynx are, meanwhile, constricted by the superior constrictors of the pharynx and by the pharyno-palatinus muscles described below. Contraction of the levator veli palatini tends to cause folds of tissue to close firmly the opening of the Eustachian tube. This is counteracted by the tensor veli palatini muscles (fig. 343). One of these arises on each side from the pterygoid region of the sphenoid bone, and is inserted into the anterior part of the soft palate by a tendon which passes beneath the hamular process of the pterygoid process. Contraction of this pair of muscles flattens the anterior part of the soft palate and exerts a traction which dilates the orifice of the Eustachian tube. Most authorities state that the Eustachian tube is thus opened each time we swaUow. As air is admitted into the middle ear the tensor tympani muscle contracts so as to prevent too sudden an effect on the ear drum (Jonnesco.)
Dorsal to the fibres of the elevator of the palate in the soft palate next the median line on each side there extends from the hard palate into the uvula a small muscle, the muscle of the uvula, which lifts the tip of this and shortens the soft palate from front to back thus enlarging the opening from the mouth into the pharynx. On each side of the uvula the posterior edge of the soft palate is continued backward and downward into a fold, the arcus pharyngo-palatinus, which contains a muscle, the pharyngo-palatinus (fig. 865). This arises from the soft palate, gasses downward and backward on the inner side of the lateral wall of the pharynx and divides iato two fasciculi, one of which is attached to the larynx, the other to the median raphe. The muscle constricts the pharynx at the junction between the nasal and buccal portions and elevates the larynx. As the bolus of food is passed from the dorsum of the tongue into the pharynx the bucco-pharyngeal opening is dilated by the contraction of the elevators of the palate and uvular muscles and the opening into the naso-pharynx is closed not only by the soft palate being raised against the posterior wall of the naso-pharynx but also by the lateral folds raised on each side by the pharyngo-palatinus against the uvula. Meanwhile the larynx is raised by the pharyngo-palatinus and the stylo-pharyngeus, as well as by the suprahyoid muscles, and carried forward by the hyo-mandibular subdivision of the latter muscles so that the opening from the pharynx into the cesophagus is dilated for the passage of food. At the same time the opening into the larynx is constricted from above, the larynx being carried forward beneath the tongue so that the epiglottis slants somewhat backward. This backward slant is aided by the constriction of the thjTeo-hyoid muscle which raises the thyreoid cartilage toward the hyoid bone and by the stylo-glossus muscle whioh pulls the tongue backward over the larynx. The opening into the larynx is constricted at the sides and behind by the contraction of muscles which run in the aryepiglottic folds and by the thyreo-arytenoid and transverse arytenoid muscles. At the end of deglutition the larynx is puUed back from beneath the base of the tongue by the middle and inferior constrictors of the pharynx and the opening is again dilated. The buccal cavity may be shut off from the pharynx by the action of the muscles which pass in the glosso-palatal folds from the soft palate to the mouth in front of the tonsils. These glosso-palatal muscles elevate the folds in which they he, depress the soft palate, and, if the dorsum of the tongue be raised, shut oft' the buccal cavity. The muscles of the soft palate are described on p. 1134.
The uvular muscle, the levator veU palaini, the glosso-palatinus and the pharyngopalatinus muscles are supphed by the pharyngeal plexus. The tensor veU palatini is supplied by the mandibular division of the fifth nerve. The pharyngeal muscles are supplied by the glosso-pharyngeal, the vagus, and the spinal accessory cranial nerves.
The larynx lies in the neck, but since the intrinsic muscles of the larynx from the standpoint of embryology and comparative anatomy belong with the musculature of the head, it is convenient to refer to them briefly here rather than to treat of them with the intrinsic muscles of the neck. A full description of the laryngeal muscles is given in the section on the larynx (fig. 981) . They develop from tissue which corresponds with that which in fishes gives rise to the muscles of the gills and are innervated by the nerves which in the fishes innervate the gills, the tenth pair (vagus) of cranial nerves. The movements of the laryngeal cartilages are such as to approximate or draw apart the vocal cords and to loosen or make them tense. The approximation of the vocal cords is produced by the rotation medialward of the vocal processes of the arytenoid cartilages brought about by the lateral crico-arytcnoid and transverse arytenoid muscles. The drawing apart of the vocal cords is produced by the posterior crico-arytenoids. The vocal cords are made long, thin and tense by the crico-thyreoid. They are shortened and thickened by the thyreo-arytenoid (externus) and the vocalis. The inferior laryngeal branch of
laryngeal branch of the vagus.
Metamerism. — The muscles thus far considered are essentially visceral muscles, although all are composed of striated muscle cells and all are more or less directly under the control of the will. From the morphological standpoint the muscles of the orbit, the tensor tympani, the muscles of mastication, the hyo-mandibular muscles and the muscles of the tongue have been grouped with the ordinary voluntary skeletal muscles while the facialis musculatm'e, the stapedius, the hyo-temporal muscles and the muscles of the soft palate, pharyn.x and larynx are looked upon as of a more purely visceral origin. A primitive characteristic of the voluntary skeletal muscles is metameric segmentation. This is maintained through life in the trunk musculature of fishes and of tailed amphibia and is passed through as a temporary stage in aU the higher vertebrates. The embryonic segmented muscles are caDed myotomes (see fig. 340). In some regions the metamerism is retained throughout life even in the higher forms, as, for instance, in the intercostal muscles and the intertransverse muscles. But for the most part the primitive metamerism is so lost during the differentiation of the definitive trunk musculature that only traces of it remain here and there as, for instance, in the segments of the rectus abdominis muscle. In the lower forms the myotomes give rise during embryonic development to material utilized in the formation of the limb musculature, but even in the fishes all traces of trunk metamerism are lost in the differentiated limb musculature and in the higher forms, as in man, the limb musculature appears to differentiate directly from the unsegmented tissue in the hmb-buds. In the head the musculature is differentiated directly, as in the limbs, without undergoing a preliminary metameric or myotomic stage. Attempts have been made to show that in primitive forms the cranial voluntary skeletal musculature, in the narrower morphological sense mentioned above, passes through a metameric stage comparable with the myotomic metamerism of the trunk. This attempt has been partially successful as regards the development of the muscles of the eye in some of the lower forms. There is also good evidence that the spinal region of the skull and associated structures represent a part of the metameric trunk fused with a more primitive head so that the musculature of the tongue and the hyo-mandibular muscles belongs morphologically with the primitively metameric trunk musculature. The rest of the cranial musculature gives little evidence of a primitive metameric segmentation and hence is probably to be classed morphologically with the unsegmented visceral musculature.
Of the muscles of the neck, the most superficial, the platysma (fig. 341), is a subcutaneous muscle belonging to the facialis group of the head from which it grows down during embryonic development. It is supplied by the seventh cranial (facial) nerve. It extends from the corner of the mouth and the side of the mandible over the clavicle. It depresses the corner of the mouth, wrinkles up the skin of the neck and aids the circulation by reUeving pressure on the uiiderlying veins.
Beneath the platysma there lies a layer composed of two flat muscles (fig. 344) which extend from the base of the skull behind the ear to the shoulder girdle. One of these muscles, the sterno-cleido-mastoid, arises in front from the sternum and clavicle and is inserted into the m.istoid process of the temporal bone and the skull behind this. The other, the trapezius, arises from the base of the skull, and from the ligamentum nuohfe and vertebral spines of the cervical and thoracic regions, and is inserted into the spine of the scapula, the acromion and the lateral third of the clavicle. These two muscles constitute the superficial shoulder -girdle musculature. They extend the head, bend it toward the same side and rotate it toward the opposite side. The sterno-cleido-mastoid and the upper part of the trapezius raise the shoulder girdle and thorax and hence are of use in forced inspiration. The trapezius draws the scapula toward the spine and rotates the inferior angle of the scapula lateralward. The lower part of the trapezius acting alone draws the scapula downward and dorsalward while rotating the inferior angle lateralward. The trapezius is therefore used when the arm is raised high or carried backward. The two muscles of this group are innervated partly by the spinal accessory, and partly by the ventral divisions of the second, third and fourth cranial nerves. They represent in part musculature which in the lower vertebrates is associated with the visceral musculature of the gills (hence the innervation by the spinal accessory, a derivative of the vagus nerve) and in part metameric musculature of the second, third, and fourth cervical segments. During embryonic development this musculature therefore spreads out widely from its origin, the upper cervical region. The lower part of the trapezius varies greatly in the extent of its development caudalward. It may reach only half way down the thoracic region or it may extend into the lumbar region. The deeper musculature of the neck is derived from the cervical myotomes.
The primitive segmental musculature of the neck, hke that of the whole trunk, becomes divided at an early embryonic stage into two divisions, a dorsal, supplied by the dorsal divisions of the spinal nerves, and a ventro-lateral supplied by the ventral divisions. The trapezius, although it covers the intrinsic dorsal musculature of the cervical region, insofar as it is of cervical origin, belongs to the ventro-lateral musculature and is derived, apparently, from the first three cervical myotomes. There is also a deeper layer of muscles attached to the shoulder girdle which arise from the ventro-lateral divisions of the lower five or six cervical myotomes but which, with one exception, the levator scapulm (fig. 353), wander over the thorax during embryonic development. This group is described below as the deep shoulder-girdle musculature. The rest of the muscles derived from the ventro-lateral divisions of the cervical myotomes are divisible into three gi'oups, the infra-hyoid, the scalene and the prevertebral.
The infra-hyoid group hes at the front of the neck, superficial to the larynx and trachea (fig. 348), and is composed of four flat muscles, the sterno-hyoid, sterno-thyreoid, thyreo-hyoid and omo-hyoid (scapulo-hyoid), the names of which indicate the origin and insertion. The chief function of this group of muscles is to depress the hyoid bone, the larynx and the associated structures. When the supra-hyoid group of muscles contracts at the same time, the infra-hyoid muscles help to depress the lower jaw, or if this in turn is fixed by the cranio-mandibular group, to flex the head. The muscles of this group are derived from the ventral portions
of the first three cervical myotomes and are innervated by the first three cervical nerves through the ansa hypoglossi. The primitive segmental origin of these muscles is frequently indicated by transverse tendons (inscriptiones tendineae). They correspond morphologically with the rectus abdominis musculature.
The scalene group (fig. 352) lies at the side of the neck and extends to the first and second ribs from the transverse processes of the lower six cervical vertebrae. The muscles of this group bend the neck toward the side, or if the neck be fixed, elevate the thorax. They come from the lateral parts of the ventro-lateral divisions of the lower five cervical myotomes and are innervated by the lower five cervical nerves. They correspond morphologically with the intercostal and with the lateral abdominal musculature.
The prevertebral group lies back of the pharynx and oesophagus and in front of the bodies and transverse processes of the cervical veitebrae. The muscles of this gi-oup arise not only from the transverse processes and bodies of the cervical vertebrae, but also in part from the bodies of the first three thoracic vertebrae and are inserted in part into the cervical vertebrae (?or!(/MS coiM) and in part into the base of the occipital bone {longus capitis). This musculature flexes the neck and the head. When acting on one side it rotates the head toward the same side. It is innervated by the first six cervical nerves.
The deep shoulder-girdle musculature. — This becomes differentiated from the ventro-lateral divisions of the lowei five or six cervical myotomes. Like the muscles of the superficial layer those of the deeper layer spread out widely from their origin. There are four muscles in the deeper group, all of which become attached to the dorsal border of the scapula. Of these, one, the levator scapulce (fig. 353), remains in the cervical region, extending from the upper cervical transverse processes to the medial angle of the scapula. Two, the rhomboids (fig. 353), extend over the intrinsic dorsal musculature and are attached to the upper thoracic and lower cervical vertebral spines; while the fourth, the serratus anterior (fig. 354), extends over the side of the upper part of the thorax beneath the scapula and is attached to the first nine ribs. These muscles all, however, through their innervation, reveal in the adult their primitive cervical origin. They are supplied by branches from the third to the seventh cervical nerves. The levator scapulae elevates the scapula, the rhomboid muscles retract it and the serratus anterior draws it forward. The levator and rhomboid muscles rotate the shoulder girdle so as to depress the shoulder, the serratus anterior, like the trapezius, rotates it so as to raise the shoulder. The two former muscles are an aid in extending the arm, the latter in flexing and abducting it. When the group, as a whole, contracts action is exerted on the ribs so that the group is of use in forced inspiration.
The intrinsic dorsal musculature of the neck, innervated by the dorsal divisions of the cervical nerves, is separated from the scalene muscles by the levator scapula. Dorsally it is covered by the trapezius and the rhomboid muscles. It is to be looked upon as a specialized portion of the system of intrinsic dorsal muscles which extend from the sacrum to the base of the skull on each side of the vertebral column. The primary function of this muscle system is to extend and to rotate the spine and the skuU. In the thoracic region three main subdivisions may be recognised, a lateral, the ilio-costal; an intermediate, the longissimus; and a medial, the transverse-spinal group (fig. 381). In the cervical region these three groups may hkewise be recognised and, in addition, there is a superficial group, the splenius (fig. 380) , not represented in the lower thoracic region. The splenius arises from the upper thoracic and lower cervicla spines and is inserted into the transverse processes of the upper cervical vertebrae and into the mastoid processes of the temporal bone and the neighbouring part of the occipital. It acts with the sterno-cleido-mastoid, by which it is crossed near the head, in extending the head, bending it toward the side, but tends to rotate it toward the same side instead of toward the opposite side. Laterally beneath the splenius the ilio-costalis cervicis extends from the upper part of the thorax to the transverse processes of the sixth to the fourth cervical vertebrae, and the longissimus cervicis and capitis extend from the same region to the transverse processes of the mid-cervical vertebrae and to the mastoid process of the temporal bone (fig. 381). These muscles likewise extend and bend the head and neck laterally and rotate it toward the same side. Medially on each side the strong semispinalis capitis (fig. 381), arises from the upper thoracic and the lower cervical vertebrae, spreads out and is inserted into the squamous portion of the occipital bone. It is a powerful extensor of the head. Beneath it numerous fasciculi extend from the transverse proceses to the spines of the cervical vertebrae. These fascicuh, the more superficial of which are the Ion', est, constitute the Scmispinales cervicis, muliifidus, and roiatores muscles. They extend and rotate the neck.
Between the successive spines and the transverse process there are short muscles (inlerspinales, intertransversares) . The rectus capitis anterior and the rectus capitis lateralis between the transverse process of the atlas and the lateral part of the occipital belong with the latter series.
Between the base of the skull behind and the first two vertebrae there are four deep-seated specialized muscles which constitute the suboccipital group (fig. 382). The rectus capitis posterior major and minor spread out respectively from the spines of the atlas and epistropheus and are inserted beneath the inferior nuchal line of the occipital. The obliquvs capitis inferior arises from the spine of the epistropheus and is inserted into the transverse process of the atlas; the obliquvs capitis superior arises from this and is inserted into the lateral part of the inferior nuchal line of the occipital. These muscles extend and rotate the head. A detailed description of the intrinsic muscles of the back is given on page 410.
The muscle fasciae in the head and neck are well developed in connection with most of the groups of muscles except the facialis group and are described in detail in connection with each of these groups. In the head we may here call attention merely to the dense temporal fascia which covers over the temporal fossa and hides from view the temporal muscle. In the neck the fasciae are of considerable practical importance. It is convenient to think of them as divisible into several layers although the various layers fuse to some extent. The external layer (fig. 350) may be looked upon as completely ensheathing the neck and as dividing on each
FACIALIS MUSCULATURE 329
side into two layers which ensheath the sterno-cleido-mastoid and trapezius muscles. As a free fascia it is attached to the lower jaw, to the clavicle and sternum, and to the hyoid bone which divides it into a submaxillary and an infra-hyoid portion. It is connected with the fibrous sheath of the parotid and submaxillary glands. The middle layer of cervical fascia is composed of two laminae, one extending between the sterno-hyoid and omo-hyoid and another more delicate one beneath this, ensheathing the thyreo-hyoid and sterno-thyreoid muscles and fused with the fibrous sheath which encloses the carotid artery, internal jugular vein and the vagus nerve. The deeper muscles of the side and front of the neck and the intrinsic muscles of the back of the neck are hkewise ensheathed by muscle fasciae.
Of the various groups of muscles mentioned above, some, for the sake of convenience, are treated in connection with the organs to which they belong. Thus the muscles of the eye and ear are taken up in Section VIII; those of the palate, pharynx and larynx in Sections IX and X; the deep dorsal musculature of the neck will be taken up in the section on the intrinsic muscles of the back, p. 410, The remaining groups of muscles will be taken up in the following order: —
The muscles of this group are intimately connected with the scalp, with the skin of the face and neck, and with the mucous membrane lining the lips and the cheeks. Most of the muscles have an osseous origin and a cutaneous insertion, but there are exceptions. Both origin and insertion may be cutaneous, or the attachment may be to an aponeurosis instead of directly to the skin. The deeper musculature about the mouth is attached to the mucous membrane.
The muscles are composed of interdigitating muscle-fibres which are grouped in bundles that take a nearly parallel or slightly converging course and give rise to thin muscle-sheets. The extent of development of the various muscles of the group and their independence varies greatly in different individuals.
The region from which the facial musculature originates in the embryo is, in the main at least, that of the hyoid arch immediately below the ear. From here the musculature spreads with the development of the facial nerve, dorsally to the occipital region behind the ear, distally over the neck, ventrally over the face, and upward toward the eye, forehead, and the side of the skull. The course of the development is indicated by the branches of the facial nerve. A somewhat similar phylogenetic development is indicated by conditions found in the inferior mammals and lower vertebrates. According to Ruge and Gegenbam-, the facial musculature is to be looked upon as derived from two muscle-sheets, of which in man the deeper has disappeared in the region of the neck while it is differentiated into the deeper facial muscles in the region of the head. The deeper layer of transverse fibres in the neck, the sphincter colli, is found in several of the mammals. The complex development of the facial muscles in man is characteristic of the human species, and is associated with the use of these muscles as a means of expression of the emotions, a physiological function superadded to the primitive function of opening and closing visceral orifices. There is much individual variation in the differentiation of the muscles.
Fasciae. — The skin of the head and neck is, in most regions, firmly fused with the tela subcutanea. This is composed of a dense fibrous tissue united by a looser areolar tissue to the underlying structures. But a slight amount of fat is embedded in the subcutaneous ti.ssue of the scalp, forehead, and nose. Considerable fat may be embedded in the region of the cheeks, the back of the neck, and the under surface of the chin (double chin). The constantly repeated action of various muscles of the facialis group usually results by middle Hfe in the production of permanent wrinkles due to alterations in the structure of the tela subcutanea and the cutis.
* The pectoral muscles and the latissimus dorsi, which extend from the skeleton of the hmb to the front and side of the thorax and the lower part of the back, arise from the hmb-bud during embryonic development, are innervated through the brachial plexus, and wiU, therefore, be taken up in considering the intrinsic musculature of the upper Imrb, p. 360.
ous tissue of the scalp. That covering the subcutaneous muscle of the neck is less firmly fused with the subcutaneous tissue. In the facial region the more superficial muscles are so closely embedded in the subcutaneous tissue that no distinct fasciae intervening between the muscles and the skin can, as a rule, be distinguished. Of the deeper muscles of the facialis group, the buccinator alone possesses a distinct fascia. This muscle lies upon the mucous membrane of the lateral wall of the mouth, and is covered externally by a fascia continued into the fascia investing the superior constrictor of the pharynx.
Bursse. — Bursa subcutanea prementalis. Between the periosteum at the tip of the chin and the overlying tissue. Bursa subcutanea prominentias laryngese. In front of the junction of the right and left laminae of the thyreoid cartilage.
The muscles of the faciahs group may be conveniently subdivided as follows: — (a) Cervical : the platysma. (&) Oral : the orbicularis oris and the incisivus labii superioris and inferioris; the quadratus labii superioris and inferioris; the caninus, zygomaticus, risorius, and triangularis; and the buccinator, (c) Mental, (d) Nasal: the nasalis, depressor septi, and the dilatores naris. (e) Periorbital: the orbicularis oculi, corrugator, and procerus. (/) Epicranial: the frontalis and occipitalis, with the galea aponeurotica. (g) Auricular: anterior, superior, and posterior. With these the temporalis superficialis is also described.
ORAL MUSCLES 331
mandible and the neck to the proximal part of the thorax and shoulder. The muscles of each side interdigitate across the chin. A short distance below the chin, in the neck, the ventral margins diverge (fig. 341).
Insertion. — Into — (1) the mental protuberance of the mandible and the inferior margin of the mandible; and (2) into the skin of the lower part of the cheek and at the corner of the mouth, where it fuses more or less with the quadratus labii inferioris and the orbicularis oris.
the muscle a plexus to which the cutaneus colh nerve contributes sensory branches.
Relations. — The muscle is situated beneath the panniculus adiposus, to which in the neck it is not very firmly attached. For the most part it is separated from the external layer of the cervical fascia by loose areolar tissue. The main cutaneous rami of the cervical plexus and the external jugular vein lie beneath the muscle.
Action. — It wrinkles up the skin of the neck, depresses the corner of the mouth, and thus plays a part in expression of sadness, fright, and suffering. It aids the circulation by relieving pressure on the underlying veins.
Variations. — Either the facial or the distal development of the muscle may be more extensive than that described above. On the other hand, it ma.y be less developed than usual, and rarely it is absent. Accessory shps have been seen going to the zygoma, the auricle, or the mastoid process, etc., and to the clavicle and sternum. Rarely a deep transverse layer is found in man.
The muscles of the mouth belonging to the facialis system include several intralabial muscles: — a sphincter, the orbicularis oris; a transverse, the compressor labii; and four deep submucous muscles which pass from the sides of the lips to the alveolar juga of the upper canine and lower lateral incisor teeth, the incisivi labii superioris and inferioris. From each corner of the mouth there radiate out several muscles; the caninus and zygomaticus upward to the maxilla and zygomatic bone; the risorius lateral ward over the cheek; the platysma and the triangularis downward over the side of the jaw; and the buccinator, lateralward over the side of the oral cavity. From each of these fibre-bundles are continued into the more peripheral and superficial portions of the orbicularis. In addition to these muscles there are two retractors or quadrate muscles, one of which, the quadratus labii superioris, extends from the upper lip medial to the angle to the bridge of the nose, the lower margin of the orbit, and the zygomatic bone; while the other, the quadratus labii inferioris, extends from a corresponding position in the lower lip to the side of the chin. The orbicularis oris, compressor labii, and incisive muscles close the lips; the other muscles open them and pull them in various directions. The buccinator, however, plays a part in the closing of the mouth by offering support for the orbicularis.
Intralabial Muscles
The orbicularis oris (figs. 308, 341, 342, 343) is a complex muscle which surrounds the oral orifice and forms the chief intrinsic musculature of the Ups. Immediately about the orifice, and on the deep surface of the muscle, is a fairly well-defined sphincter, although at the corners of the mouth the fibre-bundles of one hp cross those of the other and are inserted into the mucosa, and to a less extent into the skin. In the mid-line the fibre-l^undles end partly in the perimysium, partly in the skin. About this sphincter area and between its outer margin and
the skin is a complex musculature comprised partly of fibre-bundles prolonged from the muscles which radiate from the corners of the mouth. The more superficial portion of the muscle in the upper Up is composed of fibre-bundles from the triangularis (depressor anguU oris), the more superficial portion of that in the lower lip by fibre-bundles from the caninus (levator anguli oris). These fibre-bundles form commissures at the angles of the mouth and extend toward the median line, where many of them interdigitate with those of the opposite side, and are attached to the skin of the lips. The deeper portions are partly formed by fibre-bundles prolonged from the buccinator, the mandibular fibre-bundles of the latter muscle going mainly to the upper lip, the maxillary fibre-bundles mainly to the lower hp. These fibre-bundles are attached chiefly to the mucosa, near the corners of the mouth.
The compressor labii, or muscle of Klein, is composed of bundles of fibres which take a course transverse to those of the orbicularis, and pass obhquely from the skin surrounding the oral orifice toward the mucosa which bounds its inner margin. It is said to be best marked in infants.
mucosa than the skin. On its deep surface lie the labial arteries.
Action. — The orbicularis draws the upper lip downward, the lower lip upward. The incisive muscles draw the corners of the lips medialward, and the compressor flattens the lips. Together they serve to close the mouth. Acting separately they may draw different parts of it in the directions indicated by their structure. The circumferential portion of the orbicularis acting with the incisive muscles makes the lips protrude. The central portion of the orbicularis draws the lips together, and when the buccinator also acts, draws them against the teeth. It is this portion of the muscle that has chiefly to do with nutritive functions. The more peripheral parts of the muscle are chiefly utilised in the expression of the emotions.
which are inserted into the skin and musculature of the upper lip.
The caput zygomaticum (zygomaticus minor) is long and slender and arises from the lower part of the external surface of the zygomatic bone beneath the lower border of the palpebral portion of the orbicularis oculi. It passes obliquely forward over the caninus and orbicularis oris muscles, and extends to a cutaneous and muscular insertion in the upper hp medial to the corner of the mouth. It lies medial to the zygomaticus.
The caput infraorbitale (levator labii superioris), a broad, flat muscle, arises from the infraorbital margin of the maxilla, where it is concealed by the orbicularis oculi. It extends obhquely forward over the caninus and beneath the caput angulare to the skin and musculature of the lateral half of the upper hp.
The caput angulare (levator labii superioris alseque nasi) arises from the root of the nose, where it is fused with the frontalis. As it descends it divides into two fasciculi, one of which is attached to the skin and the alar cartilage of the nose; the other passes obliquely downward over the caput infraorbitale to the skin and musculature of the lateral half of the upper hp.
Variations. — The caput zygomaticum is often absent. It may be fused with the zygomaticus (major). It may be doubled. Its origin may extend to neighbouring structures. The other heads, though more stable, vary considerably, especiafly in the extent of their fusion with neighbouring muscles.
The quadratus labii inferioris (depressor labii inferioris) is a thin, rhomboid muscle which arises below the canine and bicuspid teeth from the base of the mandible, between the mental protuberance and the mental foramen, and extends obhquely upward in a medial direction to the orbicularis oris, through which its fibre-bundles pass. Its more medial fibres cross at their insertion with those of the muscle of the other side. It is attached to the skin and mucosa of the lower lip. It is essentially a part of the platysma, and is superficially united to the skin except where covered by the triangularis (depressor anguh oris). It crosses the mental vessels and nerves and a part of the mentalis (levator menti).
the mouth, where it becomes attached to the skin and sends some fasciculi into the orbicularis of the lower lip. Between the caninus and the quadratus labii superioris there is a certain amount of fatty areolar tissue through which the infraorbital vessels and nerves run. Its deep surface extends over the canine fossa, the buccinator muscle, and the mucosa of the Up. The external maxillary (facial) artery passes over its inferior extremity.
The zygomaticus (z. major) is a long, ribbon-shaped muscle which arises by short tendinous processes from the zygomatic bone near the temporal suture under cover of the orbicularis oculi. It passes obliquely to the corner of the mouth, where it is attached to the skin and mucosa. The body of the muscle is subcutaneous and is usually surrounded by fat. It crosses the masseter and buccinator muscles and the anterior facial vein.
The risorius is a thin, triangular, subcutaneous muscle which extends across the middle of the cheek and lies in a more superficial plane than the platysma, with which it is often fused. It arises from the tela subcutanea above the parotid fascia. Its fibres converge across the masseter muscle toward the angle of the mouth and are attached to the skin and mucosa in this vicinity. It lies above the anterior facial vein and external maxillary artery.
The platysma has been described above.
The triangularis (depressor anguli oris) is a broad, flat, well-developed, subcutaneous muscle which arises from the base and external surface of the body of the mandible below the canine, bicuspid, and first molar teeth. From here its fibres converge toward the corner of the mouth, where they are in part inserted into the skin and in part are continued into the orbicularis oris of the upper hp. It overUes the buccinator and the quadratus (depressor) labii inferioris muscles. Not infrequently (58 out of 92 bodies — LeDouble) some fascicuh are continued into
the neck as the transversus menti, a fibro-musoular band formed by the interdigitation of the slips prolonged from each side below the chin and superficial to the platysma. Santorini described the transversus menti as an independent though inconstant muscle. According to Eisler the true transversus menti muscle is to be distinguished from aberrent slips of the triangularis or of the platysma in this region. In one instance Eisler found a slender nerve emerging through the platysma and passing to this muscle.
Nerue-supply. — The zygomatic branch of the seventh nerve supphes the canine (levator anguli oris) and zygomatic (major) muscles. Branches enter the middle of the deep surface of the latter muscle and the superficial surface of the former near its lateral border. The risorius is suppUed by branches from the buccal rami of the seventh nerve, which enter its deep surface. The triangularis (depressor anguh oris) is supplied by the buccal branch through branches which enter its deep surface near the posterior margin.
Action. — The caninus (levator anguli oris) and zygomatic (z. major) muscles raise the corner of the mouth, the former at the same time drawing it medially, the latter, laterally. The caninus gives rise to expression of bitterness or menace. The zygomaticus is active in smihng or laughing. When contracted greatly it elevates the cheek and the lower eyehd and produces crow's-foot wrinkles at the corner of the eye. The risorius draws the angle of the mouth laterally. ^ In spite of its name it is not used to express pleasure, but instead gives rise to an expression of pain. The triangularis (depressor anguli oris) depresses the corner of the mouth and draws it laterally, giving rise to the expression of grief.
Variations. — The risorius is very inconstant in its development, and in its relations toneighbouring muscles, and is not infrequently quite small. The zygomaticus is rarely absent Its origin may extend to the temporal or masseteric fascias. It may be doubled throughout its length or at one extremity. Frequently the triangularis is divided into three fasciculi.
The buccinator (fig. 343) arises from — (1) the molar portion of the alveolar process of the maxilla; (2) the buccinator crest of the mandible, and (3) the pterygo-mandibular raphe of the bucco-pharyngeal fascia. This narrow fibrous band, which separates the buccinator from the superior constrictor of the pharynx, extends from the pterygoid hamulus to the buccinator crest of the mandible. The fibre-bundles are divisible into four sets. The most cranial extend directly into the orbicularis of the upper lip. The next pass through the commissure at the corner of the lips into the orbicularis of the lower lip; the third through the commissure into the orbicularis of the upper hp, and the fourth directly into the orbicularis of the lower lip. The muscle is attached chiefly to the mucosa of the lips near the angle of the mouth. Some fibrebundles extend to the more medial portion of the mucosa and some through the orbicularis to the skin.
posterior half of its outer surface.
Relations. — The muscle is covered externally by the thin bucco-pharyngeal fascia; internally by the mucosa of the mouth. Above its outer surface lie the zygomatic (z. major), risorius, and masseter muscles." The parotid duct passes forward over the muscle, and slightly in front of its centre pierces it and passes into the mouth. It is crossed by the external maxillary (facial) artery and anterior facial vein and by the buccal artery and nerve.
The mentalis (levator menti) (fig. 343) is a short, thick muscle which arises from the alveolar jugum of the lower lateral incisor tooth and the neighbouring region of the mandible under cover of the quadratus (depressor) labii inferioris and beneath the oral mucosa, where this is reflected from the lips to the gums. It extends to the chin, where it is fused with the muscle of the opposite side and is attached to the skin of the chin.
Actions. — It draws up the skin of the chin and thus indirectly causes the lower lip to protrude. It is of use in articulation, in forcing bits of food from between the gums, and in the expression of various emotions (muscle of pride) .
Toward the nasal apertures several muscles converge. Those extending from above elevate and dilate, those from below depress and contract, the nostrils. To the former belongs the pars transversa of the nasalis (compressor naris), a triangular muscle extending from the bridge of the nose to the naso-labial sulcus; the caput angulare of the quadratus labii superioris (levator labii superioris alaeque nasi), which arises from the root of the nose and sends a fasciculus to the wing of the nose; and the dilatores naris, described below; to the latter, the pars alaris of the nasalis (depressor alas nasi), which extends from the alveolar juga of the upper lateral incisor and canine teeth to the dorsal margin of the nostril; and the small depressor septi nasi.
The nasalis consists of two parts, the pars transversa and the pars alaris. The pars transversa (compressor naris) is triangular. It lies on the side of the nose above the wing. Its fibre-bundles arise from an aponeurosis which overlies the bridge of the nose, is adherent to the skin, and is not closely attached to the underlying cartilage. From this aponeurosis the fibrebundles converge toward the back of the wing, where they are attached to the skin along the fine which separates the wing from the cheek (naso-labial sulcus). Its insertion is covered by the nasal proce.ss of the caput angulare (levator labii superioris alseque nasi) of the quadratus labii superioris (p. 332), with which its fibres interdigitate. An attachment (origin) is also described by many as taking place in the lower part of the canine fossa of the maxilla.
The pars alaris (depressor ala; nasi) (fig. 343), is a small quadrangular muscle situated below the aperture of the nose, between this and the alveolar portion of the maxilla. It is covered by the mucosa of the gum, by the orbicularis oris and the quadratus (levator) labii superioris, aad laterally is fused with the pars transversa (compressor naris). It arises from the alveolar juga of the lateral incisor and the canine teeth. Its fibre-bundles extend vertically to the skin of the dorsal margin of the nostril, from the dorsal part of the cartilage of the wing to the septum
The dilator naris posterior is a thin, triangular muscle which lies on the side of the wing of the nose. It arises from the skin of the naso-labial groove and is attached to the inferior border of the wing of the nose.
ward and up the lateral margin of the wings of the nose, and gives rise to the expression of sensuaUty. (Poirier.) This accords with the electrical experiments of Duchenne. However, acting in conjunction with the alar portion, the transverse portion of the nasalis may constrict the nostrils. The alar portion (depressor alae nasi) of the nasalis and the depressor septi nasi draw down the nostril. The former tends to contract it from side to side, the latter from front to back, and at the same time to depress the tip of the nose. They play a part in the expression of anger and of pain. The functions of the other muscles are indicated by then' names.
Variations. — The muscles of the nose vary considerably in extent of development, and one or more may be absent. Authors differ considerably in their description of several of the muscles. The anomalus is a longitudinal muscle strip occasionally found running from the frontal process to the body of the maxilla near the lateral margin of the nasal aperture.
the orbicularis oculi, the corrugator, and the procerus. The orbicularis oculi is a large, flat, elliptical muscle which lies in the eyelids and over the bone surrounding the orbit. Three parts are recognised, a palpebral, an orbital and a lacrimal. The quadrangular corrugator extends from the nasal portion of the frontal bone to the skin of the middle half of the eyebrow; the narrow procerus (pyramidaHs nasi) from the bridge of the nose to the skin at the root. The muscles which have an antagonistic action are the levator palpebrse superioris and the epicranius. The levator palpebrse is described in the chapter on the Eye (see Section VIII), the epicranius in the following subsection.
The orbicularis oculi. — The palpebral portion arises from the ventral surface and margins of the lateral portion of the medial palpebral hgament (tendo oculi), and from the covering of the lacrimal sac. The fibre-bundles spread out as they pass into the eyelids and again are concentrated toward their insertion into the outer surface of the lateral palpebral ligament. Many of the fibre-bundles interdigitate here without being inserted into the ligament. The muscle in each eyelid lies between the tarsal plate and the skin, separated from both by loose tissue. The superficial muscle-fibres nearest the margin of the hds constitute the ciliary muscle, or muscle of Riolan. They are very small fibres and probably act on the eyelashes and Meibomian glands.
The orbital portion arises by a superior origin from the medial palpebral ligament (tendo ocuU), the nasal portion of the frontal bone, and the anterior lacrimal crest of the maxilla, and by an inferior origin from the medial palpebral hgament and the medial portion of the inferior rim of the orbit. The fibre-bundles form a flat ring which surrounds the orbit for a considerable distance, especially inferiorly. The muscle is adherent to the overlying skin. It hes over the bones surrounding the margin of the orbit and over the attachments of several of the facial muscles attached to these bones. With these muscles some of the fibre-bundles are usually continuous.
The lacrimal portion (tensor tarsi or Horner's muscle) arises from the posterior lacrimal crest of the lacrimal bone and passes down on the dorsal surface of the lacrimal sac and the medial palpebral ligament (tendo oculi). It bifurcates and furnishes a fasciculus attached to each tarsal plate. Some of the fibre-bundles surround the lacrimal canaliculi and some surround the ducts of the tarsal glands and the roots of the eyelashes.
The corrugator arises from the frontal bone near the fronto-nasal suture. It extends obliquely upward to be inserted into the skin of the middle half of the eyebrow. The fibrebundles of insertion interdigitate with those of the frontahs. The muscle hes relatively deep. It is covered by the procerus (pyramidahs nasi), the frontalis, and the orbicularis. Under it lie the supra-orbital vessels and nerves.
The procerus (p3rramidalis nasi) overlies the nasal bone. It arises from the lateral cartilage of the nose through a fibrous membrane and also directly from the nasal bone, and is attached to the skin over the root of the nose, where its fibres interdigitate with those of the frontalis. The medial margins of the muscles on each side are more or less fused.
of the facial nerve which enter the deep surfaces near the lateral margins.
Action. — The palpebral portion of the orbicularis closes the eyehds, of which the upper moves more freely than the lower. It also serves to dilate the lacrimal sac and allow the tears to flow away readily. The tensor tarsi probably contracts the sac and forces the tears into the nose. The upper half of the orbital portion of the orbicularis contracts and depresses the tissue overhanging the orbit, and stretches the skin of the forehead. The corrugator draws the skin of the brow downward and medially, thus aiding the preceding muscle. It causes the perpendicular furrows characteristic of frowning. The procerus (pyramidahs nasi) draws down the skin of the forehead and wrinkles the skin across the root of the nose. The lower half of the orbital portion of the orbicularis raises the skin of the cheek, causing the wrinkles seen to radiate from the corner of the eye. The whole set of muscles comes into play in the forcible closure of the eyes. In case of violent expiratory efforts, as in shouting, sneezing, coughing, etc., the eye is thus usually forcibly closed. The pressure thus exerted on the eyeball prevents a too violent flow of blood to the vessels of the eye. Pressure is thought at the same time to be exerted on the lacrimal gland so as to cause the excessive flow of tears often experienced at such times.
Variations. — The muscles of this group vary in extent and differentiation, and may be more or less fused with one another or with neighbouring muscles. The orbital portion of the orbicularis, the corrugator, and the procerus have been found absent.
The epicranius (occipito-frontalis) is formed of the two frontal muscles, which lie on each side of the forehead, the two occipital muscles, which occupy corresponding positions on the occipital bone, and of the epicranial aponeurosis, the galea aponeurotica, which extends between these. The occipital muscles arise from the supreme nuchal line and are inserted into the galea aponeurotica. The frontal muscles arise from the latter and are inserted into the skin near the eyebrows. The chief function of these muscles is to elevate the brows. The
muscles and the intervening aponeurosis lie between two layers of fascia, the external of which is fused to the skin, while the internal moves freely over the periosteum, to which it is loosely attached. Hsemorrhages and abscesses spread freely between the deep layer of fascia and the periosteum.
The frontalis is a large, thin muscle with convex upper and concave lower border. It arises from the epicranial aponeurosis midway between the coronal suture and the orbital arch, and is inserted into the skin of the eyebrow and of the root of the nose. The medial fibre-bundles take a sagittal direction; the lateral converge obhquelj' toward the brow. The medial margins of the muscles of each side are approximated near the attachment. The more medial fibre-bundles are continuous with those of the procerus (pyramidahs nasi) and the angular portion (levator labii superioris alasque nasi) of the quadratus labii superioris; the more lateral interlace with those of the corrugator and orbicularis muscles. The branches of the vessels and nerves of the frontal region pierce the muscle and are distributed between it and the skin.
The occipitalis, flat and quadrangular, lies on the occipital bone above the supreme nuchal line. It rises by tendinous fibres from the lateral two-thirds of this line and from the posterior part of the mastoid process of the temporal bone, and is inserted into the epicranial aponeurosis. The medial fibre-bundles run sagitaUy, while the lateral run obliquely forward. The occipital artery and nerve lie between the muscle and the skin. The lateral border of the muscle comes in contact with the posterior auricular muscle. The muscles of each side are usually separated by a strip of aponeurosis.
The galea aponeurotica (epicranial aponeurosis) is a fibrous membrane which extends between the occipital muscles and from them anteriorly to the frontal muscles. In the area between these two sets of muscles it is composed largely of sagitahy running fibres into which coronal fibres radiate from the region of the muscles of the ear. Between the two occipital muscles the aponeurosis is attached to the supreme nuchal line and external occipital protuberance. Laterally the fascia covering it is continued as a special investment of the auricular muscles, beyond which it is attached to the mastoid process, the zygoma, and to the external cervical and the masseteric fasciae.
Nerve-supply. — The frontahs is suppUed by the temporal branches of the facial nerve, the occipitalis by the posterior auricular branch. The branches enter the deep surface of each of these muscles near its lateral border.
Action. — The occipitalis serves to draw back and to fix and make tense the epicranial aponeurosis. The frontalis, with its aponeurotic extremity fixed, elevates the brows and throws the skin of the forehead into transverse wrinkles as in the expression of attention, surprise, or horror. When both muscles contract forcibly there is, in addition, a tendency to make the hair stand on end because the hair-bulbs of the occipital region slant forward, those of the frontal region backward. The frontalis when fixed below puUs the scalp forward.
Variations. — The ocoipitahs is occasionally absent, a condition normal in ruminants. The muscles of the two sides may be fused in the median line (normal in dogs). It may be fused with the posterior auricular. The frontalis is rarely missing. The frontalis may send shps to the medial or lateral angles or the orbital arch of the frontal bone, to the nasal process of the maxilla or to the nasal bone. The fibre-bundles of the frontalis may interdigitate across the median line.
The transversus nuchas, or occipitaUs minor, is a small muscle, frequently present (27 per cent., Le Double), which runs from the occipital protuberance toward the posterior auricular muscle, with which it may be fused. It may He over or under the trapezius.
The intrinsic muscles of the auricle are described in Section VIII. There are three 'extrinsic^ auricular muscles which converge from regions anterior, superior, and posterior to the auricle and are inserted into it.
The auricularis anterior (attrahens aurem) is a small, flat, triangular muscle which arises between the two layers of the fascia of the galea aponem-otica, extends over the zygomatic arch, and is attached to the ventral end of the helix. The fibre-bundles converge from the origin toward a tendon of insertion. The area of origin of this muscle is often marked by a fibrous band tangential to its component fibres. From this band muscle fibre-bundles radiate out toward the frontal region of the skull. To the muscle formed of these radiating fibres the names epicranio-temporalis (Henle), temporalis superficialis (Sappey) and auriculo-frontalis (Gegenbaur) have been given.
The auricularis superior (attoDens aurem) is a large, tliin, triangurar muscle which, from its tendinous insertion on the eminence of the triangular fossa of the ear, radiates upward into ' the fascia of the galea aponeurotica, between the layers of which it takes oigin near the temporal ridge. It lies over the temporal fascia and the periosteum of the parietal bone.
The auricularis posterior (retrahens aurem) is a thin, band-like muscle which extends over the insertion of the sterno-cleido-mastoid from the base of the mastoid process and the aponeurosis of the sterno-cleido-mastoid muscle to the convexity of the concha, where it has a tendinous insertion. It is usually composed of two fasciculi, and is contained between two layers of fascia derived from the galea aponeurotica.
Nerve-supply. — The aiu-icularis anterior and superior are supphed by the temporal branch of the facial, the auricularis superior and posterior by the posterior am-icular branch. The twigs of supply run to the deep surface of the muscles.
Relations. — The superficial ascending branch of the auriculo-temporal nerve usually runs superficial to the anterior and superior auricular muscles. The superficial temporal vessels run at first beneath these muscles and the lateral expansion of the galea aponeurotica, then between the two fascial layers which enclose the muscles. Their branches of distribution finally come to lie between the muscles and aponeurosis and the skin. The posterior auricular artery and nerve usually run under cover of the auricularis posterior.
retractor of the ear, but usually in man they are inactive.
Variations. — These muscles vary much in development. The most constant of them is the superior. The posterior frequently is increased in size and may be fused with the occipitalis, which originally was probably an ear muscle. From the anterior muscle a special deep fasciculus is occasionally isolated. Each of the muscles is occasionally, though rarely, absent, the anterior most frequently. An inferior auricular muscle is very rarely found in man, though present in many of the lower mammals. A slip of the posterior auricular may run beneath the ear to the parotid fascia.
The cranio-mandibular muscles, or muscles of mastication, pass from the base of the skull to the lower jaw. They are represented in the selachians by a single muscle mass, the adductor mandibulee (Gegenbaur), but in the higher vertebrates this muscle mass becomes variously subdivided during embryonic development. The muscles are innervated by the masticator nerve (motor root of the trigeminal cranial nerve, the nerve of the mandibular arch). In man four muscles are recognised, the temporal, masseter, and internal and external pterygoids.
The temporal and masseter muscles are situated on the lateral sm-face of the skull, partly under cover of muscles of the facialis group. The temporal muscle (fig. 345), which resembles the quadrant of a circle, arises from the temporal fossa and is inserted into the coronoid process of the mandible; the thick, quadrilateral masseter (fig. 344) muscle arises from the zygomatic arch and is inserted into the lateral surface of the ramus and angle of the mandible. The pterygoids (fig. 346) are more deeply seated. The cone-shaped external pterygoid arises from the lateral side of the pterygoid process and lower surface of the great wing of the sphenoid and is inserted into the condyloid process of the mandible and the capsule of the joint. The thick, quadrilateral internal pterygoid parallels the masseter. It arises from the pterygoid fossa of the sphenoid and is inserted into the inner side of the angle of the mandible. It will be noted that the tem-
FASCIJE
poral, masseter, and internal pterygoid muscles have approximately vertical axes of contraction and adduet the lower jaw, while the external pterygoid- has an approximately horizontal axis of contraction and draws the jaw forward and, when acting on one side, toward the opposite side.
The temporal fascia arises from the temporal line of the frontal bone and from the superior temporal line of the parietal and the periosteum immediately below this. It extends to the zygomatic arch. In its inferior quarter the fascia divides into two lamellae, one of which passes to the outer, the other to the inner, surface of the arch, but at the superior margin of the arch these two lamelte are united by dense fibrous tissue. Between the two lamella? above the arch hes a fatty areolar tissue in which the middle temporal artery often runs. The outer surface of the fascia is covered by the superficial temporal and anterior and superior auricular muscles, and by a thin layer of fascia from the galea aponeurotica, with which, toward the zygomatic arch, it becomes merged. The superficial temporal artery and auriculo-temporal nerve cross it.
The masseteric fascia represents essentially a continuation of the temporal fascia from the inferior margin of the zygomatic arch over the masseter muscle which it covers. It is less thick than the temporal fascia, but is firm and strong. It is attached dorsally to the dorsal margin of the mandible, mferiorly to the inferior margin, and ventrally to the body and to the ventral majgin of the ramus and the coronoid process of the mandible. In part it extends over the fat pad of the cheek to the buccinator fascia. The parotid gland, covered by the parotid extension of the external cervical fascia, extends over the posterior portion of this fascia. The parotid fascia becomes fused to its external surface at the anterior margin of the gland. Over it lie the parotid duct, the transverse facial artery, branches of the facial nerve, the zygomaticus (major), risorius, and platysma muscles.
The pterygoid muscles are each surrounded by a dehcate membrane. In addition an mterpterygoid fascia separates the two muscles. This arises from the sphenoidal spine and toUows the internal surface of the external pterygoid to the mandible. MediaUy it is attached to the lateral lamella of the pterygoid process; posteriorly and laterally it presents a free margin which forms with the neck of the mandibular condyle, an orifice for the passage of the internal maxillary artery, the auriculo-temporal nerve, and several veins. Its posterior margin is strengthened into the spheno-mandibular ligament, which runs from the spine of the sphenoid to the lingula of the mandible.
The pharyngeal region is separated from the pterygoid by a dense membrane, the lateral pharyngeal fascia. This extends from the depth of the pterygoid fossa to the prevertebral tascia, a,nd separates the tensor veh palatini from the internal pterygoid muscle. It is attached above along a Ime extending from the external margin of the carotid canal to the internal margin ot the oval foramen.
The temporalis (fig. 345). — Origin. — (1) From the whole of the temporal fossa, with the exception of that part formed by the body and temporal process of the zygomatic (malar) bone; and (2) from the fascia covering the fossa. Insertion is into the tip, dorsal and ventral borders, and the whole internal surface of the coronoid process of the mandible and the ventral portion of the medial surface of the ramus.
In structure, the muscle is thin near its superior margin, but becomes thick as its insertion is approached. The fibre-bundles arising from the medial surface of the fossa and from the fascia converge upon the medial and lateral surfaces and the margins of a thick, broad tendon which begins very high in the muscle, becomes visible laterally some distance above the zygomatic arch, and is inserted into the tip, edges, and internal surface of the coronoid process. On the ventral and dorsal margins of the tendon the insertion of fibre-bundles continues to the coronoid process, while medially the insertion of the fibre-bundles is continued on the medial surface of the coronoid process and often on the ramus as far as the body of the bone.
Nerve-supply. — Usually three branches from the anterior branch of the mandibular division of the fifth nerve curve upward over the temporal surface of the great wing of the sphenoid and enter the deep surface of the muscle. The posterior and middle nerves pass above the external pterygoid; the anterior, which springs from the buccinator nerve, passes between the two heads of the external pterygoid before curving upward.
Relations. — The muscle is covered by the temporal fascia and the zygomatic arch. Below the temporal fossa the pterygoid muscles and the buccinator lie medial to it. Fatty tissue hkewise lies between the muscle and the buccinator. Medial to the muscle run the deep temporal vessels and nerves, the buccinator nerve and the spheno-mandibular ligament. The masseteric nerve passes lateralward behind and below the tendon.
The masseter (fig. 343) is composed of two layers. The superficial layer arises by an aponeurosis from the anterior two-thirds of the lower border of the zygomatic (malar) bone. The fibre-bundles arise from the deep surface of this aponeurosis and its tendinous prolongations pass obliquely downward and backward, and are inserted into the lower half of the external surface of the ramus, into the angle, and into the neighbouring portion of the body of the man-
1. Adipose tissue. 2. Arteria temporalis superfioialis. 3. A. carotis externa. 4. A. carotis interna. 5a. A. maxillaris externa (facial). 56. A. maxillaris interna. 6. A. vertebralis. 7. Atlas. 8. Cerebellum. 9. Epistropheus (axis). 10. Fascia buccopharyngea. 11. F. cervicalis, a (superficial layer), 6, deep parotid process. 12. F. interpterygoidea. 13. F. masseterioa. 14. F. nuchie. 15. F. pharyngobasilaris. 16. F. pharyngis lateralis. 17. F. temporaHs. 18. Galea aponeurotica. 19. Glandula parotica. 20. Ligamentum stylomandibularis. 21a. Mandible, capitulum; b, coronoid process. 22. Meatus acusticus ext. 23. Medulla oblongata. 24. MeduUa spinalis (spinal cord). 25. Musculus auricularis posterior (retractor auris). 26. M. buccinator. 27. M. caninus (levator anguli oris). 28. M. constrictor pharyngis medius. 29. M. constrictor pharyngis superior. 30. M. digastricus. 31. M. genio-glossus. 32. M. hyo-glossus. 33. M. incisivus labii inferioris. 34. M. levator veli palatini. 35. M. longus capitis (rectus capitis anticus major). 36. M. longissimus capitis (trachelo-mastoid). 37. M. longitudinalis inferior. 38. _M. masseter. 39. M. mylo-hyoideus. 40. M. nasalis (alar portion). 41. M. obhquus ca,pitis inferior. 42. M. obUquus capitis superior. 43. M. pterygoideus externus — a, superior fasciculus; 6, inferior fasciculus. 44. M. pterygoideus internus. 45. M. quadratus (levator) labii superioris. 46. M. rectus capitis anterior (minor). 47. M. rectus capitis posterior major. 48. M. rectus capitis posterior minor. 49. M. rectus capitis laterahs. 50. M. semispinalis capitis (complexus). 51. M. splenius capitis. 52. M. sterno-cleido-mastoideus. 53. M. stylo-glossus. 54. M. stylo-hyoideus. 55. M._ stylo-pharyngeus. 56. M. temporalis (a, fasciculus from zygoma). 57. M. tensor veli palatini. 58. M. trapezius. 59. M. zygomaticus (major). 60. Nervus accessorius (spinal accessory). 61. N. alveolaris inferior (dental). 62. N. alveolaris posterior superior (dental). 63. N. auriculo-temporalis. 64. N. buccinatorius. 65. N. canalis pterygoidei (Vidian nerve). 66. N. glosso-pharyngeus. 67. N. hypoglossus. 68. N. Ungualis. 69. N. mandibularis. 70. N. masseteric nerve. 71. N. maxillary nerve. 72. N. mylohyoid nerve. 73. N. palatinus. 74. Sympathetic trunk. 75. N. temporalis profundus. 76. N. vagus. 77. Os occipitale — a, basilar portion; b, external protuberance. 78. Os sphenoidale. 79. Os temporale — o, processus zygomaticus; b, tubercle. 80. Os zygomaticum (malar). 81. Pharyngeal orifice of tuba auditiva (Eustachian tube). 82. Palatum durum (hard palate). 83. Pharynx — a, oral portion; b, nasal portion. 84. Pharyngeal recess. 85. Sinus maxillaris (antrum of Highmore). 86. Sinus transversus (lateral). 87. Tonsila palatina. 88. Uvula. 89. Vena facialis posterior (temporomaxillary). 90. V. jugularis interna. * This and the following series of cross-sections are taken from a thin, not very muscular,
dible — the more anterior directly, the posterior by means of an aponeurosis. The deep layer arises from the lower border and internal surface of the zygomatic arch. The fibre-bundles pass neai'ly vertically downward, and are inserted upon the upper hah of the external surface of the ramus. The origin and insertion are by tendinous bands, to which the fibre-bundles are attached in a multipenniform manner. The two layers are fused near the origin and insertion and in front. From the temporal surface of the zygomatic bone and the neighbouring part of the deep layer of the temporal fascia there arises a fasciculus which is separated by a pad of fat from the main body of the temporal muscle, and is inserted into the lateral sm-faoe of the lower extremity of the tendon of the temporal muscle and into the ventro-lateral surface of the tip of the coronoid process. This fasciculus, sometimes described as a part of the temporal muscle, is innervated by the masseteric nerve.
Nerve-supply. — The branch arises in common with the posterior nerve to the temporal muscle from the motor root of the trigeminal (the masticator nerve). It passes above the external pterygoid, through the mandibular (sigmoid) notch, and enters the deep surface of the muscle near the dorsal margin.
• I Relations. — It is covered by the masseteric fascia (see above). At the mandibular (sigmoid) notch the sigmoid septum separates it from the external pterygoid muscle. The parotid gland partly overlaps its posterior border.
The pterygoideus externus (figs. 343-346) consists of two fasciculi. Each is thick and triangular. The superior is flattened in a horizontal, the inferior in a vertical, plane. At their origin they are separated by a narrow cleft. Near the insertion they become more or less fused. The superior fasciculus arises by short tendinous processes from the infratemporal (pterygoid) crest and from the neighbouring portion of the under surface of the great wing of the sphenoid. Its fibre-bundles converge toward the insertion, which takes place by short tendinous processes into — (1) the capsular ligament in front of the articular disc and (2) the upper third of the front of the neck of the condyle. The inferior fasciculus is the larger. It arises by short tendinous processes from the lateral surface of the lateral lamina of the pterygoid process, from the pyramidal process of the palate bone, and from the adjacent portions of the maxillary tuberosity. The fibre-bundles converge toward their insertion into a depression on the front of the neck of the condyle.
Nerve-supply. — A branch from the masticator nerve (mot6r root of the trigerninus) approaches the muscle near the upper border of the medial surface of the superior fasciculus and gives branches to both portions.
Relations. — It is partly covered by the maxillary fasciculus of the internal pterygoid and by the temporal and masseter muscles. Medial to it lies the chief fasciculus of the internal pterygoid muscle. The masseteric and the posterior and middle temporal nerves usually pass above the muscle, the anterior temporal and the buccinator nerves and frequently the internal maxillary artery between the two fasciculi. The internal maxillary vessels usually pass below the lower border of the muscle and across its external surface; and the auriculo-temporal, lingual, and infei-ior alveolar (dental) nerves cross the deep surface of the muscle.
the maxillary tuberosity and the pyramidal process of the palatine, where these adjoin.
Structure and Insertion. — From the medial and lateral lamins of the pterygoid process there ai-ise aponeuroses and from the palatine bone at the lower margin of the fossa, and from the maxillary tuberosity and palatine bone in front of the external pterygoid, there arise short tendons. From these aponeuroses and tendons and directly from the fossa the fibre-bundles take a nearly parallel course downward, backward, and outward, and are inserted in part in a multi-penniform manner into the lower half of the internal surface of the ramus of the mandible. The insertion extends to the mylo-hyoid ridge. The muscle is divided at its origin into two fascicuh by the distal margin of the external pterygoid.
Nerve-supply. — The internal pterygoid nerve arises from the back of the mandibular nerve near the foramen ovale. It passes near or through the otic ganglion, and thence to the medial surface of the muscle near the dorsal edge. Both the buccinator and lingual nerves are also described as sending filaments to this muscle.
Relations. — Laterally the muscle is covered by the interpterygoid fascia and the sphenomandibular ligament, the external pterygoid, temporal, and masseter muscles, and the ramus of the mandible. The inferior alveolar (dental) and Ungual nerves and the corresponding vessels run across this surface. Medial to the muscle lie the lateral pharyngeal fascia, the tensor veh palatini muscle, and the superior constrictor of the pharynx.
Action. — The muscles of this group adduct the lower jaw and serve to carry it forward and backward and from side to side. The elevation is produced by the masseter, temporal, and internal pterygoid muscles. The suprahyoid muscles and the external pterygoid are the feeble antagonists. T?he forward movement of the jaw is produced by the simultaneous action of the two external pterygoids (slightly by the superficial layer of the masseter, and the anterior fibres of the temporal) while the inferior posterior portions of the temporal muscles carry the jaw at the temporo-discoidal joint somewhat backward. Oblique lateral rotator}' movements are produced chiefly by the action of one of the external pterygoids. The alternate action of these two msucles associated with the elevating action of the other muscles of the group, gives rise to the grinding movement of the molar teeth. Purely lateral movements of the jaw may be produced by the internal pterygoids, acting alternately. Lord (Anat. Rec, vol. 7, p. 355, 1913) states that in ordinary opening of the mouth the external pterygoids pull the articular discs and condyles forward while the jaw rotates about an axis passing through the insertions of the stylo-mandibular ligaments.
Variations. — The temporal muscle may have a more extensive cranial origin than usual. It may be formed of two superimposed layers. It may be more or less fused with the external pterygoid, or send a fasciculus to the coronoid process. The masseter may be completely
SUPRAHYOID MUSCULATURE
divided into two fasciculi, a condition normal in many mammals. A special fasciculus may arise from the temporo-mandibular articulation or from the zygomatic (malar) bone. Its deepest fibres may be fused with the temporal muscle. The two fasciculi of the external pterygoid may be distinct, as in the horse. It has been seen fused with the temporal and with the digastric muscle. The internal pterygoid may send a fasciculus to the masseter. It may give origin to the stylo-glossus. Inconstant fasoiouh (accessory pterygoids) extending from the body of the sphenoid to the pterygoid process represent perhaps remnants of the muscles which act on the movable pterygoids possessed by many inferior vertebrates.
the musculature of the tongue and pharynx. They elevate the hyoid bone and larynx and depress the mandible. The most superficial of the group is the slender, fusiform stylo-hyoid, which arises from the styloid process of the temporal bone and is inserted into the body of the hyoid. Immediately behind this is the flattened posterior belly of the digastric, which extends from its origin in the mastoid notch to a tendon that runs between two divisions of the tendon of the stylo-hyoid and is attached to the hyoid bone by an aponeurotic process. From the digastric tendon the flat, triangular anterior belly is continued to the back of the ventral portion of the inferior margin of the mandible. Internal to this anterior belly the thin, quadrangular mylo-hyoid arises from the inner surface of the body of the mandible and is inserted into a median raphe extending from the mandible to the hyoid. Still more internally the triangular genio-hyoid extends from the hyoid to the mental spine of the mandible. The last two muscles form the muscular floor of the mouth. The motor innervation of the posterior belly
of the digastric and of the stylo-hyoid is from the seventh cranial nerve, the sensory innervation probably from the glosso-pharyngeal cranial nerve. The mylo-hyoid and the anterior belly of the digastric are supplied by the masticator (fifth) cranial nerve; the genio-hyoid from the hypoglossal by a branch, the fibres of which are possibly derived through anastomosis from the first cervical nerve.
From the morpliological standpoint, therefore, the stylo-hyoid and the posterior belly of the digastric belong to the faciahs group; the anterior belly of the digastric and the mylo-hyoid to the group of mandibular muscles, and the genio-hyoid to the muscles of the tongue innervated by the hypoglossal, or, if we consider the nerve-fibres of the nerve to the genio-hyoid as derived from the first cervical nerve, to the same group as the infra-hyoid muscles. It is convenient, however, to follow the usual custom of considering these muscles as a suprahyoid group.
The muscles of this group he internal to that portion of the external cervical fascia which extends above the hyoid bone. This fascia, which is described on p. 347, comes into contact merely with the tendon, the anterior belly, and to a slight extent with the posterior belly of the digastric muscle. Above the tendon it sends inward a process which curves down internal to the tendon, and is inserted into the external surface of the hyoid bone. The individual muscles of the group are covered by dehcate adherent membranes. An aponeurotic membrane usually extends between the anterior bellies of the digastric muscles of each side.
The stylo-hyoideus. — Origin. — From the lateral and dorsal part of the base of the styloid process by a rounded tendon which soon becomes a hollow cone to the internal surface of which the fibre-bundles of the muscle are attached. Structure and Insertion. — The fibre-bundles are inserted on both sides of a slender tendon which divides to let the tendon of the digastric pass through and then is attached to the ventral surface of the body of the hyoid bone near its junction with the great cornu.
pharyngeal nerve also gives to it a small twig, probably sensory.
Relations. — It descends immediately in front of the posterior belly of the digastric. Externally lie the parotid and submaxillary glands. Medially it crosses the internal and ex-ternal carotid artery, the hypoglossal nerve, the stylo-pharyngeus muscle, the superior constrictor of the pharynx, and the hyo-glossus muscle. The posterior auricular artery passes between it and the posterior belly of the digastric and the external maxillary artery crosses over it.
The digastricus. — The posterior belly arises by tendinous processes from the mastoid (digastric) notch of the temporal bone. The fibre-bundles form a ribbon-)ike belly which converges on the intermediate tendon. This begins as a semiconical laminar process on the outer surface of the muscle a short distance above the hyoid bone. The anterior belly arises by short tendinous processes from the digastric fossa of the mandible. This attachment is often described as an insertion. The fibres converge on both surfaces of the flattened anterior end of the intermediate tendon. The intermediate tendon hes a variable distance above the hyoid bone, usually less than a centimetre. It curves upward toward each belly of the muscle. It is united to the outer surface of the body and to the base of the great cornu of the hyoid bone by an aponeurotic expansion from its inferior margin. Other expansions are usually continued into the interdigastric aponeurotic membrane. Occasionally the intermediate tendon of the digastric is bound to the hyoid bone by a fibrous loop which allows the tendon free play.
Nerve-supply. — The facial nerve near the stylo-mastoid foramen gives off a branch which enters the proximal third of the anterior margin of the muscle. From this a ramus may be continued through the muscle to the glosso-pharyngeal nerve. The anterior belly is supplied by a branch of the nerve to the mylo-hyoid muscle. This enters the middle of the lateral part of the deep surface. Very rarely the vagus may supply the anterior belly, the hypoglossal, the posterior belly.
Relations. — The posterior belly of the digastric lies internal to the mastoid process and the longissimus capitis (trachelo-mastoid), splenius, and sterno-cleido-mastoid muscles. Posteriorly near its origin are the rectus capitis lateralis and obliquus cap. sup. muscles, the occipital artery and the spinal accessory nerve. It helps to form the deep wall of the cavity in which the parotid gland is placed. Internally it crosses the origin of the styloid muscles, the carotid arteries, the internal jugular vein, and the twelfth cranial nerve. The intermediate tendon of insertion hes below the inferior margin of the submaxillary gland, and crosses the hyoglossus and mylo-hyoid muscles. The relations to the stylo-hyoid muscle have been described above.
The mylo-hyoideus. — Origin. — From the mylo-hyoid ridge of the mandible. Structure and Insertion. — Its fibre-bundles take an oblique course and are inserted into — (1) a median raphe extending from the middle of the ventral surface of the hyoid bone nearly or quite to the
MUSCLES OF THE TONGUE 345
dorsal surface of the inferior margin of the mandible, and (2) into the ventral surface of the hyoid bone. Some of the fibre-bundles may cross the median line. The muscles of the two sides form a sheet with a downward convexity which lies between the inner surface of the body of the mandible and the hyoid bone. On the diaphragm thus formed rests the tongue.
filaments enter the under surface of the muscle.
Relations. — The mylo-hyoid muscle is covered externally by the submaxillary gland, the anterior belly of the digastric, and the external cervical fascia. It is crossed by the submental artery. With the genio-hyoid and the genio-glossus muscles it helps to bound a cornpartment in which are lodged the sublingual gland, the duct of Wharton, and the deep portion of the submaxillary gland. Its deep surface also faces the stylo-glossus and hyo-glossus muscles, the lingual and hypoglossal nerves, and to a slight extent the buccal mucosa.
The genio-hyoideus (fig. 349). — Origin. — By short tendinous fibres from the mental spine of the mandible. Structure and Insertion. — The fibre-bundles diverge and are inserted into the ventral surface of the body of the hyoid bone. Usually a special fasciculus goes to the great cornu of the hyoid bone.
cervical nerve.
Relations. — It lies between the genio-glossus and mylo-hyoid muscles. It adjoins its fellow of the opposite side and is often fused with it. Lateral to it he the subhngual and submaxillary glands and the hypoglossal nerve.
Action. — The muscles of this group all elevate the hyoid bone and, through this, the larynx and inferior part of the pharynx, and thus play a part in the act of swallowing. The stylohyoid and posterior belly of the digastric serve also to draw the hyoid bone in a dorsal direction; the ventral belly of the digastric and the genio-hyoid, in a ventral direction. The digastric, genio-hyoid, and mylo-hyoid depress the mandible, when the hyoid bone is fixed. The posterior belly of the digastric has a slight power to bend the head backward.
Variations. — The stylo-hyoid tendon frequently passes entirely in front of and less frequently entirely behind the digastric muscle. Its insertion may be of greater extent than usual. A special fasciculus to the lesser cornu is not very infrequent; more rarely one extends to the angle of the jaw or to other regions. The muscle may arise from the petrous portion of the temporal or from the occipital bone, as in some lower vertebrates. It may be doubled or absent, or fused with the posterior belly of the digastric. The anterior belly of the digastric may be missing; the posterior belly may be inserted into the angle of the jaw. The intermediate tendons of the digastric of each side may be connected by a fibrous arch. The anterior bellies of the muscles of each side may be united by a fasciculus or fused. The anterior belly is frequen tly doubled. The posterior belly may be divided by a tendinous inscription. Fasciculi may pass from either belly to neighbouring structures. The mylo-hyoid may not extend quite to the hyoid bone. It may be more or less fused with neighbouring muscles. Rarely it is absent. The genio-hyoid is frequently more or less fused with the muscles of the tongue or with the geniohyoid of the opposite side. A considerable number of infrequently found muscles have been described superficial to the stylo-hyoid and digastric muscles. Most of them are innervated by the glosso-pharyngeal nerve or by the facial nerve.
The tongue is a flexible organ, composed chiefly of various muscles, some of which lie entirely within its substance, while others extend to be attached to neighbouring parts of the skeleton. To the former the term intrinsic, to the latter the term extrinsic, is frequently applied. In this section the extrinsic muscle will alone be taken up. The intrinsic muscles are described in the section on the Digestive System. Certain pharyngeal and palatal muscles which are continued into the tongue are described in connection ^vith the pharynx. The extrinsic musculature of the tongue is concealed below by the suprahyoid musculature and the sublingual gland. It is covered on the free surface of the tongue by the mucosa.
The musculature of the tongue is supplied by the hypoglossal nerve, which is in series with the motor roots of the spinal nerves. It is, primitively at least, derived from the ventral portion of mj'^otomes in series with the spinal myotomes.
Four extrinsic muscles are recognised on each side. The stylo-glossus is a slender muscle, which arises from the styloid process and is inserted into the side of the tongue. It is cylindrical near its origin, flat and triangular near its insertion. The thin, quadrilateral hyo-glossus arises from the body and great cornu of the hyoid bone and is inserted into the dorsum of the tongue. The chondroglossus arises from the lesser cornu of the hyoid bone and joins the superior and inferior longitudinal muscles of the tongue. The genio-glossus (genio-hyoglossus), which forms the main part of the body of the tongue, arises from the mental spine of the mandible, from which the fibre-bundles radiate out toward the whole length of the dorsum of the tongue and to the hj'oid bone.
Under the mucous membrane of the tongue is a dense layer of fibrous tissue, the lingual fascia. In the body of tlie tongue there is a sagittal septum linguae, which separates the two genio-glossus muscles. A transverse fibrous lamella, the hyo-glossal membrane, helps to unite the tongue to the hyoid bone. Delicate membranes invest the free portions of the extrinsic muscles of the tongue.
The stylo -glossus. — This arises from the front of the lower end of the styloid process of the temporal bone and from the upper part of the stylo-mandibular ligament. Insertion. — It runs obliquely downward, forward, and medially, with slightly diverging fibre-bundles, to the lateral margin of the tongue, where it gives rise near the anterior pillar of the fauces to two fasciculi. The larger, lateral, longitudinal fasciculus runs superficially along the lateral margin of the tongue to the tip. The fibre-bundles are attached to the overlying mucosa and underlying musculature. The smaller, inferior, transverse fasciculus gives rise to diverging fibrebundles which pass medially through the hyo-glossus into the base of the tongue. The most posterior of these diverging bundles may extend to the hyoid bone.
The hyo-glossus. — This arises from — (1) the lateral part of the ventral surface of the body of the hyoid bone and (2) from the upper border of the great cornu. The fibre-bundles take a nearly parallel course upward, diverging, however, slightly. Near the upper margin of the back
digastric
part of the tongue they curve mcdianward and interlace with the intrinsic musculature of this region. The dorsal fibre-bundles pass transversely, the middle obliquely, the ventral longitudinally. They are inserted into the fibrous tissue which forms the skeletal framework of the tongue.
The chondro-glossus is a small muscle which arises from the lesser cornu of the hyoid bone and gives rise to fasciculi which join the longitudinalis inferior and the longitudinalis superior of the tongue described in Section IX.
The genio-glossus. — This arises from the mental (genial) suine of the mandible partly directly, partly by means of a short, triangular tendon. The more inferior fibre-bundles radiate toward the tip of the tongue; the intermediate extend directly toward the dorsum of the tongue, where they are inserted into the lingual fascia and skeletal framework. The inferior curve back to be inserted on the median part of the superior border of the hyoid bone.
of this group.
Action. — The chief of the muscles, the genio-glossus, performs various services according to the part which contracts. The anterior portion serves to withdraw the tongue into the mouth and depress the tip; the middle portion to draw the base of the tongue forward, depress the median portion of the tongue, and make the tongue protrude from the mouth; the inferior fibres to elevate the hyoid bone and carry it forward. The stylo-glossus retracts the tongue, elevates its margin, and raises the hyoid bone and base of the tongue. The hyo-glossus draws down the sides of the tongue and is also a retractor. The chondro-glossus aids in both these movements.
Relations. — The main portion of the tongue is composed of the two genio-glossus muscles, which are separated in the median line by the hngual septum. The genio-glossus is covered inferiorly by the genio- hyoid and the mylo-hyoid muscles; along the lateral margin of the tongue by the glosso-palatinus, the stylo-glossus, the longitudinalis inferior, and the glosso-pharyngeus
CERVICAL FASCIA 347
muscles; and posteriorly by the hyo-glossus, and the chondro-glossus. Below it forms a part of the medial wall of the space in which the sublingual gland is lodged. Over the dorsum and tip of the tongue it is covered by the mucosa. This likewise covers laterally, in the region of the base of the tongue, the stylo-glossus, hyo-glossus, and the longitudinalis inferior. The lingual artery runs between the hyo-glossus and the genio-glossus, and along the boundary between the longitudinalis inferior and the genio-glossus to the tip of the tongue. The lingual vein, which lies lateral to the hyo-glossus muscle, takes a similar although much more irregular course. The glosso-pharyngeal nerve passes down medial to the stylo-glossus muscle to the root of the tongue. The hngua! nerve passes along the lateral margin of the tongue external to the styloglossus, hyo-glossus, and inferior longitudinal muscles. The hypoglossal nerve hes lateral to the inferior portion of the hyo-glossus muscle and then sinks into the genio-glossus.
The hyo-glossus muscle is covered laterally below the free portion of the tongue by the mylohyoid, digastric, and stylo-hyoxd muscles and by the deep part of the submaxillary gland. Medially it covers in part the middle constrictor of the pharynx.
The stylo-glossus muscle above the tongue hes medial to the stylo-hyoid and the internal pterygoid muscles and the parotid gland, and between the internal and external carotid arteries. It lies lateral to the superior constrictor of the pharynx.
Variations. — The genio-glossus often sends a slip to the epiglottis (levator epiglottidis) . It may send some bundles into the superior constrictor of the pharynx (genio-pharyngeus) or to the stylo-hyoid hgament. Various parts of the muscle may be more or less, isolated. Of these, a fasciculus from the mental (genial) spine to the tip of the tongue is the most frequent (longitudinalis linguae inferior medius). The hyo-glossus exhibits considerable variation in structure. Some authors consider the chondro-glossus but a portion of this muscle, while Poirier considers it merely the origin of the longitudinalis inferior. The stylo-glossus may be absent on one side or on both. Its origin varies considerably and may be from the angle of the jaw. The muscle may be doubled.
The stemo-cleido-mastoid is a strong, band-shaped muscle, bifurcated below, which arises from the medial third of the clavicle and the front of the manubrium and is inserted into the mastoid process of the temporal bone and the neighbouring part of the occipital. The large, fiat, triangular trapezius arises from the occipital bone and the spines of the cervical and thoracic vertebrae and is inserted into the lateral third of the clavicle and into the acromion and spine of the scapula. The two muscles lie in a well defined layer of fascia which ensheaths the neck beneath the platysma, the external cervical fascia. Both muscles bend the head and neck toward the shoulder, rotate and extend the head, and raise the shoulder. The sterno-cleido-mastoid also elevates the thorax and flexes the neck.
These two superficially placed muscles represent differentiated portions of a musculature found in elasmobranchs and in the amphibia and all higher vertebrates. In sharks this musculature is associated with the musculature of the branchial arches, and, hke them, is innervated by the vagus nerve. In the higher vertebrates it is innervated by the vagus or by the spinal accessory nerve, developed in connection with the vagus. To this innervation by a cranial nerve, innervation by cervical nerves is added in those higher vertebrates in which the musculature is more extensively developed. In the human embryo the muscles migrate from their origin in the upper lateral cervical region to the positions found in the adult.
the platysma.
The external cervical fascia (fig. 350) lies beneath the subcutaneous tissue and the platysma, completely invests the neck and extends cranialward over the parotid gland to the zygoma and the masseteric fascia. The trapezius hes between two closely adherent lamince of the fascia. From the ventral margin of the trapezius it is continued as a thin but strong membrane across the posterior triangle of the neck, between this muscle and the sterno- cleido-mastoid, and is attached below to the clavicle. It invests the sterno-cleido-mastoid with two adherent laminse and extends from the ventral margin of this muscle across the anterior triangle to the mid-line where it is continued into that of the opposite side. In this triangle the fascia is bound to the hyoid bone, and is thus divided into a submaxillary and an infrahyoid portion. The infrahyoid portion is simple and is attached below to the front of the manubrium. The submaxillary portion is attached to the inferior margin of the mandible. It covers the submaxillary gland, and along the inferior margin gives rise to a strong, membranous 'process which passes inward below the gland and, after extending around the tendon of the digastric muscle, becomes united
to the superior margin of the hyoid bone. This process ventrally becomes fused with the perimysium of the ventral belly of the digastric. Dorsally it extends over the posterior end of the submaxillary gland and becomes attached to the angle of the jaw. Here it is strengthened by fibrous tissue which extends in from the ventral margin of the sterno-cleido-mastoid and serves to separate the parotid from the submaxillary gland. This 'mandibular process' is continued into the stylo-mandibular ligament.
Fig. 350. — Fascia op the Neck. (After Eisler.) The superficial fascia has been removed in places in order to show the deeper fasciaj; the sterno-cleido-mastoid has been partly removed; the submaxillary gland, almost wholly; the parotid gland, as far as the duct.
1. Submaxillary space. 2. Parotid space. 3. Sterno-cleido-mastoid. 4 Supra-clavicular fossa. 5. Supra-sternal space. 6. External jugular vein. 7. Anterior jugular vein. 8. Median colU vein. 9. N occipitaUs minor. 10. N. aurioularis magnus. 11. Deltoid. 12.^Proc. coracoideus. 13, Fascia ooraco-clavieularis.
The parotid gland is enclosed between two laminae of the external cervical fascia. These are continued over the gland from the fascial investment of the sterno-cleido-mastoid, and unite ventrally to become fused to the masseteric fascia along the anterior margin of the gland. They unite below the inferior margin of the gland, and are continued into the rnandibular process mentioned above. The external layer, which is the thicker and stronger, is attached above to the cartilage of the auditory canal and to the zygoma. The inner lamina is attached above
TRAPEZIUS 349
to the base of the temporal bone. It is incomplete and is more or less fused to the posterior belly of the digastric muscle, the styloid process, and the muscles arising from this process. Between the styloid process and the angle of the jaw this lamina is strengthened to form the stylo-mandibular ligament.
In the back, beyond the spine of the scapula, the fascia arising from the investing adherent fascial sheath of the trapezius muscle is continued laterally across the fascia investing the infraspinatus muscle, and becomes fused with the most superficial layer of this fascia and more djstally with that of the latissimus dorsi muscle. Near this lateral line of fusion it is usually closely adherent to the tela subcutanea.
The sterno-cleido-mastoideus (fig. 348). — Origin. — By a medial (sternal) head from the front of the manubrium and by a lateral (clavicular) head from the upper border of the median third of the clavicle. Between the two origins there intervenes a triangular area covered by the external cervical fascia. Its insertion is — (1) on the anterior border and outer surface of the mastoid process, and (2) on the lateral half of the superior nuchal line of the occipital bone.
Structure. — The tendons are comparatively short, the longest being that on the anterior surface of the sternal attachment. The fibre-bundles of the muscle take a nearly parallel course from origin to insertion. Five fasciculi may be more or less clearly recognised. In a superficial layer — (1) a superficial sterno-mastoid; (2) a sterno-occipital; and (3) a cleidooccipital. In a deep layer — (4) a deep sterno-mastoid and (5) a cleido-mastoid.
Nerve-supply. — (1) From the spinal accessory nerve, which gives it branches during its course through the deep portion of the muscle, and (2) by branches from the anterior primary divisions of the second and third (?) cervical nerves. These branches enter the deep surface of the upper half of the muscle.
Action. — To bend the head and neck toward the shoulder and rotate the head toward the opposite side. When both muscles act, the neck is flexed toward the thorax and the chin is raised; or, with fixed head, the sternum is raised, as in forced respiration. When the head is bent back, the two muscles may further increase the hyperextension.
Relations. — The muscle and its sheath are covered externally by the tela subcutanea, which here contains the platysma and the external jugular vein, as well as the superficial branches of the cervical plexus. Beneath the muscle lie the sterno-hyoid, sterno-thyreoid, omo-hyoid. levator scapuliE, scaleni, splenius, and digastric muscles, the cervical plexus, the common carotid artery, internal jugular vein, and the vagus nerve. The spinal accessory nerve usually runs through its deep cleido-mastoid portion.
Variations. — There is considerable variation in the extent of independence of the main fasciculi of the muscle. In many of the lower animals the cleido-mastoid portion of the muscle is quite distinct from the sterno-mastoid portion, and this condition is frequently found in man. The cleido-occipital portion of the muscle is that most frequently absent (Wood found it present in 37 out of 102 instances). The clavicular portion of the muscle varies greatly in width. The sternal head has been seen to e.xtend as far as the attachment of the fifth rib. Slips from the muscle may pass to various neighbouring structures. The main fascicuU of the muscle may be doubled. Sometimes one or more tendinous inscriptions cross a part or the whole of the superficial layer of the muscle.
The trapezius (fig. 355). — Origin. — By aflat aponeurosis from the superior nuchal fine and external protuberance of the occipital bone, the ligamentum nuchte, and the vertebra! spines and supraspinous ligament from the seventh cervical to the twelfth thoracic vertebra. The aponeuroses of the right and left muscles are continuous across the middle fine. Between the middle of the ligamentum nuchae and the second thoracic vertebra, the aponeuroses give rise to an extensive quadrilateral tendinous area. At the distal extremity of the muscle they are also weU developed.
Structure and Insertion. — The superior fibre-bundles pass obliquely downward, lateralward, and forward to the postero-superior aspect of the lateral third of the clavicle; the middle fibrebundles, transversely to the medial edge of the acromion and the upper border of the spine of the scapula; the lower fibre-bundles, obliquely upward and laterally to terminate thi'ough a flat, triangular tendon on a tubercle at the medial end of the spine of the scapula.
Nerve-supply. — The external branch of the spinal accessory nerve descends for a distance near the superior border of the trapezius muscle and then along the ventral surface. Soon it gives rise to ascending branches for the superior portion of the muscle and descending branches for the middle and inferior portions. The main branches of distribution run about midway between the origin and insertion of the fibre-bundles. The branches from the second (?), third and fourth cervical nerves anastomose with the trunk of the spinal accessory, sometimes as it passes along the margin of the muscle, at other times within the substance of the upper portion of the muscle.
Action. — When the whole muscle contracts, it draws the scapula toward the spine and turns it so that the inferior angle points laterally, the lateral angle upward. In addition the upper portion draws the point of the shoulder upward, and with the scapula fixed extends the head, bends the neck toward the same side, and tm'ns the face to the opposite side. The lower portion of the muscle tends to draw the scapula downward and inward and at the same time to rotate the inferior angle of the scapula outward.
infraspinatus muscles.
Variations. — The lower limit of attachment of the muscle may be as high as the fourth thoracic vertebra. The right and left muscles are seldom symmetrical. The upper attachment may not extend to the skull. The clavicular attachment may be much more extensive
than normal or may be missing. The attachments to the scapula show considerable variations. Occasionally the cervical and thoracic portions are separate, a condition normal in many mammals. VentraUy the trapezius may become continuous with the sterno-cleido-mastoid in the neck, or send a fasciculus to it or to the sternum. Aberrant fasciculi are not infrequent. Rarely a transverse tendinous inscription is found in the cervical or in the thoracic portion of the muscle. Sometimes a fasciculus is sent into the deltoid. The innervation of either the sterno-cleido-mastoid or the trapezius may be by cervical nerves only. The omo-cervicalis {levator claviculce) is a fasciculus frequent in the lower mammals, but rarely found in man. It usually extends from the acromial end of the clavicle to the atlas and axis, but may extend to more distal cervical vertebrae. It is innervated by a ramus from the cervical branches to the trapezius. The supra-clavicularis proprius is a muscle rarely found. It extends on the cranial surface of the clavicle from the sternal to the acromial end and is innervated by the third cervical nerve. It is said to make tense the superficial layer of the cervical fascia.
A bursa is often found between the base of the spine of the scapula and the tendon of insertion of the thoracic portion of the trapezius. Another bursa is also frequently found between the insertion of the transverse portion and the supraspinous fascia.
The four infrahyoid muscles constitute a well-defined group of muscles which depress the hyoid bone, the larynx, and the associated structures. They lie beneath the sterno-cleido-mastoid muscle and the external cervical fascia. Two strata may be recognised. In the superficial stratum are comprised the omohyoid, a narrow, ribbon-like digastric muscle which arises from the superior margin of the scapula and is inserted into the hyoid bone; and the thin, quadrangular sterno-hyoid, which arises from the superior margin of the sternum and the medial end of the clavicle and is inserted into the hyoid bone. Between these two muscles is an aponeurotic membrane which constitutes the main part of the middle layer of the cervical fascia, and represents possibly a retrograde portion of a single muscle, of which the two above named are but the ventral and dorsal margins. Beneath this superficial musculature the thin, quadrangular thyreo-hyoid descends from the hyoid bone to the thyreoid cartilage, and the ribbon-like stemo-thyreoid arises from the dorsal surface of the manubrium and is inserted into the thyreoid cartilage.
The muscles of this group are derived from the ventral portions of the ventro-lateral divisions of the first three cervical myotomes, and correspond with the rectus abdominis muscle, which is derived from the ventral portions of the eighth to the tweUth thoracic myotomes. This musculature is characterised by metameric segmentation, which may be more or less obscured, and by a general longitudinal direction taken by the component fibre-bundles. The course of the fibres in the omo-hyoid may be looked upon as a secondary condition due to the shifting laterally of the distal attachment of the muscle. Musculature of this nature is not derived from the lower cervical and upper thoracic myotomes in man, but in some of the lower vertebrates it forms a continuous ventral band. Even in man occasional traces of this ventral musculature may, however, be seen as muscular and aponeurotic slips on the upper part of the thoracic wail, above the ribs and the aponeurosis of the external intercostal muscles.
The middle cervical fascia is composed of two laminae. Of these, the superficial, which ensheaths the sterno-hyoid and omo-hyoid muscles and fills in the intervening area, is much the stronger and better differentiated. The more delicate deep lamina ensheaths the thyreo-hyoid and sterno-thyreoid muscles, and laterally extends out to become fused with the superficial lamina. It is also more or less closely bound to the sheath which covers the internal jugular vein, carotid artery, and vagus nerve.
The middle cervical fascia is attached above to the hyoid bone. Beyond the lateral edge of the omo-hyoid it becomes fused with the deep lamina of the external layer of the cervical fascia, beneath the sterno-cleido-mastoid. Posterior to this muscle it usually terminates along the cranial margin of the omo-hyoid in the areolar tissue of the neck. Its distal attachment takes place into the dorsal surface of the upper margin of the sternum, and from here a process is sent over the left innominate vein to the pericardium. Lateral to the sternum the fascia is attached for some distance to the inner margin of the clavicle, and gives rise to processes, one of which extends to the fascia of the subclavius muscle, while the others pass on each side of the subclavian vein to the first rib. Still more laterally the fascia is fused along the lower margin of the scapular belly of the omo-hyoid to the underlying dense, fatty areolar tissue.
The sterno-hyoideus. — Origin. — From (1) the deep surface of the medial extremity of the clavicle; (2) the costo-clavicular (rhomboid) ligament; and (3) the neighbouring part of the sternum. The origin may extend to the cartilage of the first rib. Structure and insertion — The fibre-bundles take a nearly parallel course upward. The muscle belly, however, contract, slightly in width and increases slightly in thickness and slants somewhat toward the median Hne. The insertion takes place directly upon the inferior margin of the body of the hyoid lateral to the mid-line. Not infrequently a tendinous inscription near the junction of the middle and inferior thirds more or less completely divides the muscle into two portions. A second inscription is sometimes found at the level of the oblique line of the thyreoid cai'tilage. Nervesupply. — One or more branches from the ansa hypoglossi enter the lateral margin of the muscle. Frequently one goes to the upper third, another to the lower third, of the muscle.
The omo-hyoideus. — Origin. — From the superior margin of the scapula near, and occasionally also from, the superior transverse ligament of the scapula. Insertion. — The lower border of the hyoid bone lateral to the sterno-hyoid muscle. Structure. — The inferior belly of the muscle near its origin is thick and fleshy. It contracts as it passes ventrally across the posterior triangle of the neck. Beneath the sterno-cleido-mastoid it is attached to a short tendon from which, as it bends upward toward the hj-oid bone, the superior belly takes origin and thence expands toward the insertion. The tendon of attachment is short. The fibre-bundles of both bellies take a nearly parallel course. The central tendon of the muscle is held in place by a strong process in the middle layer of the cervical fascia. This process is attached to the dorsal surface of the clavicle and to the first rib. Nerve-supply. — The superior belly is supphed by a branch which enters its deep surface near the medial margin somewhat below the centre; the inferior by a branch which enters the proximal third of its deep surface. These branches arise from the ansa hypoglossi.
jjThe sterno-thyreoideus. — Origin. — Partly directly, partly by tendinous fibres, from — (1) the dorsal surface of the manubrium from the middle line to the notch for the first rib; (2) the dorsal surface of the cartilage of the first rib. Occasionally also from the back of the cartilage of the second rib or from the clavicle. Structure and insertion. — The fibre-bundles take a nearly parallel course upward and shghtly lateralward. The muscle is inserted by short tendinous fibres into the oblique hne on the lamina of the thyreoid cartilage. A transverse tendinous inscription near the upper border of the interclavicular hgament not infrequently divides the belly of the muscle more or less completely into two parts. Sometimes a second transverse inscription is found at the level of the lower margin of the thyreoid cartilage. Nerve-supply. — By one or two branches from the ansa hypoglossi, which enter the ventral surface of the muscle near the lateral margin. One branch usually goes to the upper, another to the lower, third of the muscle.
The thyreo-hyoideus. — Origin. — From the oblique line on the lamina of the thyreoid cartilage. Structure and insertion. — The fibre-bundles take a parallel course and are inserted on the inferior margin of the lateral third of the body of the hyoid bone and the external surface of the great cornu. Many fibre-bundles are continuous with those of the sterno-thyreoid. Nerve-supply. — By a branch of the hypoglossal which enters the muscle near the middle of its lateral border. The fibres are said to be derived from the first cervical nerve.
Action. — The sterno-hyoid and omo-hyoid depress the hyoid bone; the sterno-thyreoid depresses the thyreoid cartilage; and the thyreoid-hyoid approximates the bone to the cartilage. The omo-hyoid tends to draw the hyoid bone somewhat laterally. In this it is aided by the posterior bell}' of the digastric and the stylo-hyoid and is opposed by the sterno-thyreoid and thyreo-hyoid muscles, and the anterior belly of the digastric.
Relations. — The muscles of this group he beneath the external cervical fascia. The sternocleido-mastoid muscle crosses the omo-hyoid, the sterno-hyoid, and sterno-thyreoid muscles. The latter two'muscles extend for a distance behind the manubrium of the sternum. The omohyoid is partly covered by the trapezius, crosses the scalene muscles, the brachial plexus, the internal jugular vein, carotid artery, and the sterno-thyreoid and thyreo-hyoid muscles. The sterno-hyoid extends over the sterno-thyreoid muscle, the thyreoid gland, crico-thyreoid muscle, and the thyi'eoid cartilage. The sterno-thyreoid Ues over the innominate veui, the trachea, and thyreoid gland. It is partly covered by the sterno-hyoid and omo-hyoid muscles. The thyreo-hj'oid is largely covered by the omo-hyoid and sterno-hyoid muscles, and lies upon the hyo-thyreoid membrane and the upper part of the thyreoid cartilage.
Variations. — The muscles vary in extent of development and may be more or less fused with one another. The sternal attachment of the sterno-hyoid is more frequently absent than the clavicular attachment. The region between the omo-hyoid and sterno-hyoid may be composed of muscle instead of fascia. Each of the muscles may be longitudinally divided into two distinct fascicuh, may send fascicuU to one another or to the middle layer of the cervical fascia, or may have an abnormal origin or insertion. The omo-hyoid is the one of the group most frequently absent. One of the bellies is much more frequently absent than both. The intermediate tendon of the omo-hyoid may be reduced to a tendinous inscription or even disappear entirely. The distal attachment maj' take place on the scapular spine, the acromion, the coracoid process, or even the first rib or clavicle. An extra fasciculus from the clavicle is found in 3 per cent, of instances. (Le Double.). Not very infrequently a muscle innervated by a branch of the descendens hypoglossi is found extending from the sternum to the clavicle behind the origin of the sterno-cleido-mastoid. It may also extend from the sternum or clavicle in various directions upward toward the head.
The bursa m. sterno-hyoidei is in constantly found between the lower margin of the hyoid bone and median hyo-thyreoid ligament and the sterno-hyoid muscle and external cervical fascia. It is better developed in men than in women and is found either on each side of the median line or fused in the median line.
The three muscles which form this group constitute a triangular mass which extends in front of the levator scapulae and intrinsic dorsal musculature and behind the prevertebral musculature from the first two ribs to the transverse processes of the cervical vertebrae. They cover laterally the apex of the pleural cavity. They bend the neck and fix the first two ribs or raise the thorax. In front lies the scalenus anterior, which extends from the first rib to the fourth to skth vertebrae. Behind this the scalenus medius extends from the first rib to the lower six vertebrae. The most dorsal of the group, the scalenus posterior, extends from the second rib to the fifth and sixth vertebrae.
These muscles are supplied by direct branches of the cervical nerves. They are probably derived from the lateral portions of the cervical myotomes. According to Gegenbaur, the two more ventral are homologous with intercostal muscles, the dorsal with the levatores costarum. It is to be noted, however, that the anterior muscle lies in front of the brachial plexus, i. e., in a position similar to that of the subcostal musculature. The scalene musculature is morphologically closely related to the deep shoulder-girdle musculature, p. 356.
From the front of the bodies of the cervical vertebrae the prevertebral fascia is continued laterally over the longus colli and the scalene muscles, and extends dorsally into the fascia covering the levator scapulae. Between the muscles fascial processes are sent in to become attached to the cervical vertebras. Interiorly the fascia extends to the outer surface of the thorax.
The scalenus anterior. — This arises from the ventral part of the inferior border of the transverse processes of the fourth, fifth, and sixth cervical vertebrae, usually also from the third, rarely from the seventh, by means of long, slender tendinous processes. From each tendon arises a fasciculus composed of nearly parallel fibre-bundles. The fasciculi soon fuse to form a muscle belly which contracts somewhat toward the insertion. This takes place by means of
1. Arteria carotis communis. 2a. A. cervicalis profunda. 2b. A. cervicalis superficiaUs 3. A. thoracoacromialis (acromial branch). 4a. A. thyreoidea inferior. 4b. A. thyreoidea superior. 5. A. transversa colli. 6. A. transversa scapulae. 7. A. vertebralis. 8. Bursa m. subscapularis. 9. Cartilago arytenoidea. 10. Cartilago thyreoidea. 11. Clavicle. 12. Costa I. 13. Costa II. 14. Fascia cervicalis — a, superficial layer; b, middle layer. 15. Deep or prevertebral layer. 16. Fascia coraco clavicularis. 17. Fascia nuchas. IS. Glandula thyreoidea. 19. Humerus. 20. Ligamentum coracohumerale. 21. Medulla spinalis (spinal cord). 22. Musculus arytenoideus transversus. 23. M. biceps brachii, tendon long head. 24. M. constrictor pharyngis inferior. 25. M. deltoideus. 26. M. Uio-costalis. 27. M. infraspinatus. 28. M. levator scapulae. 29. M. longissimus capitis (trachelo-mastoid). 30. M. longissimus cervicis. 31a. M. longus colli. 31b. M. longus capitis (rectus capitis anticus major). 32. M. omo-hyoideus. 33. M. platysma. 34. M. rhomboideus minor. 35. M. scalenus anterior. 36. M. scalenus medius. 37. M. semi' spinalis capitis (oomplexus). 38. M. serratus anterior. 39. M. serratus posterior superior. 40. M. splenius. 41. M. sterno-cleido-mastoideus. 42. M. sterno-hyoideus. 43. M. sterno-thyreoideus. 44. M. subclavius. 45. M. subscapularis; a, tendon. 46. M. thyreo-arytenoideus (and vocalis). 47. M. thyreo-hyoideus. 48. M. transverso-spinales. 49. M. trapezius. 50. Nervous accessorius. 51. N. cervicalis IV. 52. N. laryngeus inferior. 53. N. descendens hypoglossi. 54. Sympathetic trunk. 55. N. thoracaUs I. 56. N. vagus. 57. (Esophagus. 58. Plexus brachialis. 59. Scapula — a, glenoid cavity; b, ooracoid process; c, spine. 60. Trachea. 61. Vena transversa colli. 62. V. jugularis externa. 6.3. V. jugularis interna. 64. Vertebra cervicalis V. 65. Vertebra cervicalis VII. 66. Vertebra thoracalis I, arch. 67. Vertebra thoracalis II — a, spine; b, transverse process.
The tendon is inserted into the scalene tubercle on the upper surface of the body of the first rib.
The scalenus medius. — This arises usually from the third to the seventh, sometimes from aU seven or from merely the last four or five cervical vertebrrs. The origin takes place from the posterior part of the lateral border of the transverse processes by means of a slender tendon from each of the upper and directly by a muscular fasciculus from each of the lower vertebrae. The .fasciculi become combined into a compact muscle belly which is inserted in a manner similar to the scalenus anterior into the upper surface of the fu-st rib behind the subclavian groove. The insertion usually extends to the second rib.
The scalenus posterior arises by short tendons from the posterior tubercles of the transverse processes of the fifth and sixth cervical vertebrae. The origin may extend as high as the fourth vertebra, or as low as the seventh. It is inserted by a short tendon into the lateral surface of the second rib. Occasionally it extends to the third rib.
posterior
Nerve-supply. — The scalenus anterior is innervated by branches from the'fifth, sixth, and seventh cervical nerves; the middle by the fourth, fifth, sixth, seventh, and eighth cervical nerves; the posterior by the seventh or eighth nerves.
Action. — With the thorax fixed the scalene muscles bend the neck to the side and sUghtly forward and turn it sUghtly toward the opposite side. With the neck fixed they serve to lift the first two ribs and are of use in enforced inspiration. In quiet inspiration they serve to fix the first two ribs.
Relations. — The longus colli lies medial to the scalenus anterior. DorsaUy the scalene muscles; medially the pharynx, thyreoid gland, and trachea; ventro-lateraUy the sterno-cleidomastoid, infra-hyoid, and subclavius muscles and the clavicle bound a space filled with dense fatty areolar tissue in which are contained the subclavian and carotid arteries, the subclavian and internal jugular veins, the vagus, phrenic, and sympathetic nerves, and numerous smaller blood-vessels and nerves. The main branches of the lower five cervical nerves pass laterally between the scalenus anterior and medius. The subclavian artery passes behind, the subclavian vein in front, of the attachment of the scalenus anterior. The scalenus medius above and the scalenus posterior below enter into relations dorsally with the levator scapulae and the intrinsic dorsal musculature, from which they are separated by fascial septa.
PREVERTEBRAL MUSCLES 355
Variations. — The scaleni present numerous variations in the extent of the costal and vertebral attachments. The degree of fusion of the various fasciculi likewise varies so much that diiferent authors have described varying numbers of muscles into which the scalenus mass should be subdivided. A muscle frequently present is the scalenus minimus. This arises from the anterior tubercle of the sixth or sixth and seventh cervical vertebrte, and is inserted into the first rib behind the sulcus for the subclavian artery. It sends a process (Sibson's fascia) to the pleural cupola and serves to make the pleura tense. Zuckerkandl found it in 22 out of 60 bodies on both sides; 12 times on the right side only, 9 times on the left. It is innervated by the eighth cervical nerve. When absent, a ligamentous band takes its place. An intertransversarius lateralis longus, may extend from the posterior tubercles of the 3-5 transverse processes to the tip of the seventh transverse process and divide the muscle fasciculi near their origin into dorsal and ventral divisions.
This deep-seated musculature extends along tiie ventro-Iateral sm-faces of the three upper thoracic and the cervical vertebrEe to the skull. It is composed of two muscles. The longus colli arises from the bodies of the three thoracic and from the bodies and transverse processes of the third to the sixth cervical vertebrae, and is inserted into transverse processes and bodies of the cervical vertebrae. The longus capitis (rectus capitis anterior major) arises from the transverse processes of the fourth, fifth, and sixth cervical vertebrae, and is inserted into the basilar process of the occipital bone. These muscles flex, abduct, and rotate the head and neck. All of them are supplied by direct branches from the anterior divisions of the cervical nerves. They are probably specialised from the ventrolateral portions of the cervical myotomes. Similar muscles are found in all vertebrates with well-developed necks. The rectus capitis anterior (minor) represents an anterior cervical intertransverse muscle.
The muscles are firmly bound to the vertebral column by the prevertebral fascia described in connection with the scalene muscles and by the septa which extend in between the muscles of this group and between them and the scalenus anterior.
The longus colli. — This muscle may be compared to a triangle, the base of which extends from the anterior tubercle of the atlas to the body of the third thoracic vertebra and the apex of which is the transverse process of the fifth cervical vertebra. The complex construction of the muscle makes it advisable to consider it as divided into three parts.
The supero-lateral portion consists of fasciculi which arise from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebrse and from the body of the third thoracic and become fused into a belly which is inserted into the anterior tubercle of the atlas.
The median portion is formed of muscle fasciculi which arise from the antero-lateral p.irts of the bodies of the first three thoracic vertebrae and the last three cervical vertebrae by tendinous processes. These fasciculi fuse into a belly which terminates by three flat tendinous fasciculi on the antero-lateral surfaces of the bodies of the second, third, and fourth cervical vertebras.
The infero -lateral portion is applied to the inferior lateral surface of the median portion. It arises from the lateral parts of the bodies of the first three thoracic vertebrae and is inserted by tendinous processes into the transverse processes of the fifth and sixth cervical vertebrae.
to the various constituent fasciculi of the muscle.
The longus capitis (rectus capitis anterior major). — Origin. — By cylindrical tendons from the tips of the anterior tubercles of the third, fourth fifth, and sixth cervical vertebras. The tendons send up aponeurotic expansions on the outside of the fasciculi, which arise from them. These fasciculi fuse into a dense muscular belly to which is usually added a fasciculus from the longus colli. The insertion takes place into the impression on the inferior sui'face of the basilar portion of the occipital bone, extending lateral to the pharyngeal tubercle outward and forward. The insertion of the fibre-bundles from the third vertebra is direct; the other fibrebundles are inserted largely into a tendinous lamina which covers the middle of the ventral surface of the muscle and from which, in turn, other fibre-bundles arise. It is an incomplete digastric muscle. Nerve-supply. — The first, second, third, and fourth cervical nerves send branches into the ventral surface of the muscle.
Actions. — The longus colli serves to bend the neck forward; the supero-lateral portion, when acting on one side only, serves slightly to bend the neck toward that side and to rotate it; the infero-lateral portion serves especially to prevent hyperextension. The longus capitis bends the head forward; one side acting alone rotates the head toward that side.
Variations. — There is considerable variation in the number of vertebrje to which the tendons of origin and insertion of the longus colh and longus capitis may be attached and in the extent of fusion of the different fasciculi composing them. There may be fusion with the scalenus anterior. The atlantico-hasilaris internus in 4 per cent, of cases extends from the anterior tubercle of the atlas to the base of the skull.
The anterior intertransverse muscles extend successively between the anterior tubercles of the cervical vertebrte. They lie in front of the anterior divisions of the cervical nerves and are supplied by branches from these divisions. They are usually more or less bound up with the insertions of the scalene and prevertebral muscles into these tubercles. The muscle between the atlas and epistropheus is frequently missing; when present, it passes in front of the lateral articulation between these vertebrte. The rectus capitis anterior (minor) may be considered a continuation of the series. The lowest muscle may extend between the seventh cervical vertebra and the first rib. The lateral intertransverse muscles lie immediately behind the ventral divisions of the spinal nerves and lateral to the dorsal divisions and are supplied by branches from the ventral divisions. The rectus capitis laterahs belongs to this series. The rectus capitis anterior (minor) arises from the lateral mass of the atlas and is inserted into the base of the occipital bone. The rectus capitis lateralis runs from the transverse process of the atlas to the lateral part of the occipital. For the posterior intertransverse muscles see p. 417.
The rectus capitis anterior (minor). — This arises from the upper surface of the lateral mass of the atlas in front of the articular process and partly from the neighbouring transverse process. From a tendon the fibre-bundles extend in a nearly parallel direction upward and medially to be inserted on the inferior surface of the basilar portion of the occipital bone in front of the condyle Nerve-supply. — From the first (and second) cervical nerves. Action. — The rectus capitis anterior (minor) serve to bend the head forward and, when the muscles on one side only are contracted, to rotate the head toward the same side.
Relations. — The muscles of this group are closely apphed to the vertebral column. Between the fascia covering them and the fascia surrounding the pharynx which lies in front is a region in which merely a slight amount of loose areolar tissue is found. Dorso-mediaUy the longus colli below and the longus capitis above help to bound the space in which the chief vessels and nerves extend between the thorax and the head.
Relations. — In front lie the anterior primary division of the suboccipital nerve and the internal jugular vein. Behind the muscle lie the superior oblique and the longissimus capitis (trachelo-mastoid) muscles and the atlanto-occipital joint.
To this group belong four muscles which arise in the lateral cervical region during embryonic development and become secondarily attached to the vertebral margin of the scapula. One of these muscles, the band-like levator scapulae (fig. 353), remains in the cervical region. It extends beneath the sterno-cleidomastoid, the trapezius, and the intervening fascia from the transverse processes of the first four cervical vertebrae to the medial angle of the scapula. A second, the large, quadrilateral serratus anterior (magnus) (fig. 354), comes to lie beneath the blade of the scapula and wanders with this to the thoracic region. It arises, in the adult, from the first nine ribs and is inserted into the vertebral margin of the scapula. The flat, quadrangular rhomboideus major and rhomboideus
DEEP SHOULDER MUSCLES
minor (fig. 353) arise from the spines of the last cervical and first four or five thoracic vertebrae, pass obliquely downward across the deep dorsal muscles beneath the trapezius and are inserted into the vertebral margin of the scapula. The third to the seventh cervical nerves supply this set of
muscles. The levator scapulae is supplied by the third and fourth cervical nerves, the rhomboids by the fifth (dorsal scapular), the serratus anterior by the fifth to the seventh (long thoracic nerve). The muscles of this group elevate the scapula, rotate it, and draw it backward (rhomboidei) or forward (serratus anterior). When all contract together they raise the thorax.
The levator soapulse and the serratus anterior (magnus) are two differentiated parts of a muscle which is a continous mass in many of the lower mammals. A muscle corresponding to the rhomboideus is found in some of the reptiles and many of the higher vertebrates. In some of the mammals it has a more extensive cervical attachment than in man.
The levator seapulEc is invested by fascial membranes, the external and stronger of which is continued dorsaUy from the fascial investment of the scalene muscles. The thinner layer on^its deep surface Hes next the fascial investment of the intrinsic muscles of the back. Cranialward from the rhomboid muscles the fascial investment of the levator scapulse is fused dorsally with the fascia covering the splenius cervicis. Where the dorsal margin of the levator comes in contact with the rhomboideus minor, the fascia is continued over into the thin fascial mem-
brane which invests both surfaces of the rhomboidei. Similarly the investing fascia of the levator is continued ventrally into the fascia investing both sm'faces of the serratus anterior (magnus). Within the internal fascial investment of this group of muscles, near the insertion of the levator, run the transversa coUi artery and the dorsal scapular nerve.
The rhomboideus minor (fig. 353). — Origin. — ^Lower part of the ligamentum nuchse, the spines of the seventh cervical and first thoracic vertebrae, and the intervening supraspinous Ugament. Insertion. — Vertebral border of the scapula near the spine.
Structure. — The two muscles are included between two adherent fascial layers which bridge over the greater or less space that may intervene between them. The fibre-bundles take a parallel course obliquely downward and lateralward from the vertebrae. From the vertebral spines the muscles arise by an aponeurosis which varies in width. The attachment to the scapula is by short tendinous processes. The attachment of the rhomboideus major is firmest toward the inferior angle of the scapula.
Nerve-supply. — The dorsal scapular nerve, which usually arises chiefly from the fifth cervical nerve, enters the superior margin of the rhomboideus minor and then courses distaUy near the deep ventral surface of the two muscles and about midway between the tendons of origin and insertion.
rotate it so as to depress the shoulder.
Relations. — Over the muscles lies the trapezius. Under them he the serratus posterior superior and the splenius cervicis, the longissimus dorsi, the iho-costalis, serratus posterior superior and external intercostal muscles. The descending ramus of the transversa ooUi artery descends on the deep surface. Blood-vessels for the trapezius pass to this muscle between the two rhomboids.
Variations. — There is much variation in the extent of the vertebral attachment. The minor is frequently, the major occasionally, absent. The two rhomboids are frequently fused with one another or may be divided into several distinct fascicuU. Frequently (SO per cent., Balli) a fasciculus extends obliquely on the deep surface of the R. major from the cranial part of the origin to the distal part of the insertion. Shps may be sent to the latissimus dorsi or the teres major. An accessory slip may pass between the trapezius and splenius muscles to the occipital bone (occipito-scapularis). A muscle corresponding to this fasciculus is normally found in many mammals.
The levator scapulae (figs. 353, 388). — Origin. — By short tendons from the dorsal tubercles of the transverse processes of the first four cervical vertebras, between the attachments of the splenius cervicis and scalenus medius muscles. The tendons from the third and fourth cervical vertebrae are fused for a short distance with those of the longissimus cervicis. Structure and insertion. — The fibres run in parallel bundles in a dorso-lateral direction downward to the vertebral border of the scapula opposite the supraspinous fossa. The fibre-bundles are inserted directly into the periosteum. As a rule, the flat fasciculi arising from the different vertebrae are easily separated.
Nerve-supply. — By rami chiefly from the third and fourth cervical nerves. These rami enter the ventral margin of the muscle and extend obhquely across the dorsal surface of the constituent fascicuh about midway between the tendons of origin and insertion. Frequently anastomosing branches pass between the nerves. The lowest fasciculus is usually supplied by branches from the nerve to the rhomboid muscles (dorsal scapular).
Action. — Draws the scapula upward and tends to rotate it so that the inferior angle approaches the spine. When the scapula is fixed, the muscle serves to bend the neck laterally and slightly to rotate it toward the same side and extend it.
Relations. — Externally the sterno-cleido-mastoid and, in part, the splenius capitis cover it above; the trapezius, below; and the external cervical fascia, its middle portion. Internally lie the splenius cervicis, longissimus and ilioeostaUs cervicis (transversalis cervicis), and serratus posterior superior muscles and the ramus descendens of the transversa colU artery. In front lie the scalene muscles.
Variations. — The number of cervical vertebrae from which the muscle springs varies from two to seven. The most constant are the slips of origin from the fii'st two vertebrae. The muscle may send slips to the temporal or the occiptal bone or to the trapezius, the serratus anterior (magnus), serratus posterior superior, and other muscles, or to the clavicle, first or second rib, etc. Often the parts of the muscle running to each vertebra are separated for the whole distance. A bundle of fibres that appears to be a detached shp of the levator scapulae may run from the first two or from lower cervical vertebrae to the lateral end of the clavicle and to the acromion. This represents the levator claviculae found normally in many vertebrates. According to Le Double, it is innervated by a branch from the cervical branches to the trapezius group.
The serratus anterior (magnus) (figs. 354, 388). — First Pari. — The origin is by two digitations from the first and second ribs and from a fibrous arch uniting these two attachments. The fibre-bundles converge to be inserted on an oval space on the costal surface of the scapula near its medial angle. Second Part. — This arises by two or three digitations from the second, third, and sometimes the fourth ribs. The fibre-bundles spread out into a thin sheet which is inserted along the vertebral border of the scapula. Third Part. — This, the strongest part of the muscle, arises by digitations from the fourth or fifth to the eighth or ninth ribs. The attachments of the digitations are longest on the upper border of each rib. The interdigitate with the attachments of the external oblique muscle of the abdomen. The fibre-bundles converge to be inserted on the large oval space on the costal surface near the inferior angle of the scapula.
Nerve-supply. — From the proximal portions of the anterior divisions of the fifth, sixth, seventh, and sometimes the eighth cervical nerves branches arise which fuse into the long thoracic nerve. This nerve usually passes laterally through or behind the scalenus medius muscle, courses along the outer surface of the serratus anterior midway between the origin and insertion, and gives rise to numerous twigs to supply the various divisions. The fibres to the upper portion come mainly from the fifth cervical nerve; those to the middle from the fifth and sixth; and those to the lower from the sixth and seventh.
Action. — -The muscle holds the scapula against the thorax and draws it forward and laterally and, by its highly developed inferior portion, rotates the bone so as to raise the point of the shoulder. It is of especial importance in abduction of the arm. It also aids, to a slight degree, in forced inspiration.
Relations. — Superficial to the muscle lie the peotoralis major and minor, subscapularis, teres major, and latissimus dorsi muscles, the subclavian and axillary vessels, and the brachial plexus. Between the latissimus dorsi and pectoral muscles it is covered by skin and fascia inferiorly, and superiorly by the fatty areolar tissue of the axiUary fossa. Under it he the external intercostal, serratus posterior superior, and the lower extremity of the scalenus medius and posterior muscles.
Variations. — -The digitations may extend to the tenth or only to the seventh rib. The muscle may be continuous with the levator scapulae as it is in the carnivora, or some of its upper digitations may be wanting. Slips may be continued into neighbouring muscles. The lower digitations may be partially replaced by digitations innervated by intercostal nerves.
MUSCLES OF UPPER LIMB 361
freedom of movement which permits their developing many important functions. Primitively of value in climbing, in seizing food, preparing it for eating and carrying it to the mouth, in attack and defense, their importance has been greatly increased through the invention and use of tools, at first simple but constantly increasing in complexity. They are also used as a means of social expression, as seen primitively in the shrugging of the shoulders, or in the varied movements of the arms which accompany heated discourse, and as finally developed in the art of writing. In order to understand the muscles which are called into play in the performance of these varied functions it is necessary to consider the various types of movement which take place at each of the joints. Since, however, most muscles act on more than one joint and the different parts of a muscle may act differently on the same joint, it is convenient to take up the muscles of each region of the limb in groups, based not so much upon the action of the muscles on any one joint as upon the development of the group and the innervation of the muscles composing it.
Movement of the scapula is of essential importance in the movements of the arm. The scapula is kept against the thorax by muscular attachments and atmospheric pressure, but it may be moved forward, backward, upward, and downward, and may be rotated so that the glenoid fossa, with which the head of the humerus articulates, is pointed forward when the arms are carried forward, lateralward when the arms are abducted, upward when the arms are raised high and somewhat downward when the arms are carried backward, thus greatly increasing the extent of movement in these various directions. The acromio-clavicular, and sterno-clavieular joints both allow hmited movements in various directions so that they resemble physiologically limited ball and socket joints. The part played by the superficial and deep shoulder-girdle muscles in the various movements has been described above, p. 356, in connection with these groups of muscles. The action of these muscles is aided by the "pectoral muscles," (figs. 360, 388) and by the latissimus dorsi (fig. 355) described below. These muscles depress the scapula*
At the humero-scapular or shoulder-joint the arm may be carried outward or abducted, bodyward or adducted, forward or flexed and backward or extended. The last is much more hmited in degree than the other two. The arm may also be partially rotated at this joint. These various movements are brought about by the scapulo-humeral muscles (figs. 355, 356, 363) and by the latissimus dorsi (fig. 355) and the pectoralis major, (fig. 360) assisted by the muscles of the arm which arise from the scapula. They are produced in association with the movements of the scapula described above. At the ulno-humeral joint the movements are relatively simple, consisting of flexion and extension. Extension is produced at the elbow by the dorsal muscles of the arm (fig. 363), flexion is produced not only by the ventral muscles of the arm, which are inserted into the radius and ulna (fig. 364), but also by the more superficial of both the main groups of muscles of the forearm. The pronation of the forearm, whereby the palm is turned downward, and supination, whereby it is turned upward, take place in the joints between the radius and ulna at each extremity and between the radius and the lower end of the humerus. At the upper radio-ulnar joint the radius is turned on its long axis, at the lower joint it is carried about the lower end of the ulna. Pronation is produced chiefly by muscles belonging to the ulno-volar group of forearm muscles (fig. 370) ; supination is produced by the biceps of the arm (fig. 364) in conjunction with some of the muscles of the radio-dorsal group of the forearm (fig. 367). At the wrist joints (radio-carpal, intercarpal), the movements are those of flexion, extension, radial abduction and ulnar abduction. Volar flexion takes place chiefly at tlie radio-carpal joint, dorsal flaxion at the intercarpal joint (Frohse). Extension is produced by those muscles of the radio-dorsal group of the forearm, which send tendons to the wrist and digits, flexion by the corresponding muscles of the ulno-volar group, radial abduction is produced by the radial carpal extensors (fig. 367), and flexor ulnar abduction by the ulnar carpal extensor and flexor (fig. 370). The varied movements of the thumb and fingers, flexion, extension, abduction, and adduction are produced partly by muscles of the two chief groups of forearm muscles, partly by the intrinsic muscles of the hand. Of chief interest here are the free movements of the metacarpal of the thumb and the hmited movements of the other metacarpals, that of the little fingers being the most movable, as seen in spreading or cupping the hand. In flexion and extension of the metacarpal of the thumb the movement is such as to bring the thumb into opposition to the fingers. In the metaoarpo-phalangeal joints those of the fingers admit of much greater freedom of movement, flexion, extension, abduction, and adduction, than that of the thumb. The interphalangeal joints are pure hinge joints and permit merely flexion and extension.
Divisions. — The muscles described in this section as the muscles of the upper limb are all differentiated from the blastema of the embryonic limb bud. Most of them are differentiated in connection with the skeleton of the limb and extend between the various bones which compose it, but a few grow out from the limb bud over the trunk and become secondarily attached at one extremity to the trunk, while the other extremitj' remains attached to the skeleton of the limb. Thus the pectoral muscles (fig. 360), extend from the limb bud over the front of the thorax and the latissimus dorsi extends over the side and back of the trunk
as far as the iliac crest (fig. 355). The muscles of the limb may be divided into two great divisions, a dorsal division, innervated by nerves arising from the back of the brachial plexus (supra- and subscapular, axillary and radial nerves) and a ventral division innervated by nerves arising from the front of the plexus (subclavian, anterior thoracic, musculo-cutaneous, median and ulnar). The former, which correspond with the musculature on the back of the shark's fin, are in the main extensors; the latter, which correspond with the musculature on the front of the shark's fin are in the main flexors. The bellies of the muscles of each division are found in the region of the shoulder and thorax, the arm, the forearm, and the hand.
The shoulder muscles belong to the dorsal division. They arise from the lateral third of the clavicle and from both surfaces of the scapula and are inserted into the upper part of the humerus. They include the deltoid (fig. 355), the chief abductor of the arm; the supraspinatus, the infraspinatus and the teres minor (fig. 363), all lateral rotators; the subscapularis (fig. 356), the chief medial rotator; and the teres major (fig. 355) , a medial rotator and adductor. With these may be classed the latissimus dorsi (a medial rotator, adductor and extensor) (fig. 355), which arises from the dorsolumbar fascia and the crest of the ilium and is inserted into the upper part of the shaft of the humerus. These muscles are supplied by the suprascapular, the subscapular, and the axillary nerves.
The pectoral group belongs to the ventral division. It includes the pedoralis major (fig. 360) , a powerful flexor and adductor of the arm arising from the anterior chest wall and inserted into the shaft of the humerus; the pectoralis minor (fig. 388), which arises from the chest wafl and is inserted into the coracoid process of the scapula, and the subclavius (fig. 361), which extends from the first rib to the clavicle. These muscles are supplied by the subclavian and the anterior thoracic nerves.
In the arm the dorsal division is represented by the triceps and anconeus, (fig. 363). The triceps arises from the scapula and the back of the humerus and is inserted into the olecranon process of the ulna. The anconeus arises from the radial epicondyle of the humerus and is inserted into the olecranon process. Both muscles extend the forearm. The triceps also adducts the arm. They are supplied by the radial nerve.
The ventral division is made up of the coraco-brachialis (fig. 365) ; the biceps (fig. 364); and the brachialis (fig. 365). The coraco-brachialis (fig. 365), arises from the tip of the coracoid process of the clavicle and is inserted into the shaft of the humerus. It adducts and flexes the arm. The biceps (fig. 364), arises by a short head from the coracoid process and by a long head from the scapula above the glenoid fossa and is inserted into the radius and the fascia of the forearm. It flexes and supinates the forearm. The long head is an abductor, the short head an adductor and flexor of the arm. The brachialis (fig. 365), arises from the lower part of the shaft of the humerus and is inserted into the ulna. It is a flexor of the forearm.
The two main divisions of the musculature of the forearm give rise to the prominences on each side of the elbow-joint. Their peculiar arrangement with respect to the humerus is because in man, as in most tetrapods, the normal position of the forearm is one of pronation and in this position the back of the forearm is in line with the radial epicondyle, the front with the ulnar epicondyle. The dorsal or extensor muscles, springing from the lower end of the humerus (fig. 367), get the most direct purchase when attached to the radial epicondyle, and the ventral or flexor muscles (fig. 370), the most direct purchase when attached to the ulnar epicondyle. The two divisions of the musculature may therefore here be designated the radio-dorsal and the ulno-volar or volar divisions. The main bulk of the musculature is found in the upper part of the forearm. At the wrist numerous tendons pass over to the wrist, palm and digits. This arrangement facilitates movement of the hand.
The muscles of the dorsal division (figs. 367, 368, 369), are divisible into two groups, a superficial and a deep group. Those of the superficial group arise from the radial side of the lower end of the humerus and are inserted into the dorsal end of the radius (brachio-radialis) , the radial and ulnar sides of the metacarpus {extensor carpi radialis longus and b7-evis and extensor carpi ulnaris) and into the backs of the digits {extensores digitorum) . The deeper muscles arise chiefly from
the ulna and are inserted into the radius (supinator), the thumb (abductor pollicis longus, extensor pollicis loncjus and brevis) and index-finger (extensor indicis proprius, fig. 369) . All are supplied by the radial nerve. The chief function of the brachio-radialis is to flex the forearm. The chief functions of the other muscles are indicated by their names.
The volar musculature (figs. 370, 371, 372, 375) arises from the medial side of the lower end of the humerus and from the front of the radius and ulna and is divisible into four planes. The muscles of the most superficial plane, pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris, arise from the humerus and are inserted respectively into the radius, the radial side of the metacarpus, the palmar fascia and the ulnar side of the metacarpus. In the second layer the flexor digitorum sublimis arises from the humerus and the upper part of the radius and ulna and sends tendons to the second row of phalanges of the fingers. In the third layer the flexor digitorum profundus and flexor pollicis longus arise from the radius and ulna and send tendons to the terminal row of phalanges. In the fourth layer a single muscle, the pronator quadratus (fig. 377), extends in the lower part of the forearm from the radius to the ulna. These muscles are supplied mainly by branches of the median nerve but the ulnar nerve supplies the flexor carpi ulnaris and a part of the flexor profundus digitorum. The chief functions of these muscles are indicated bj^ their names.
In the hand (figs. 368, 375, 376, 377, 379) there are several sets of intrinsic muscles. About the metacarpal of the thumb is grouped a set of muscles which arise from the carpus and metacarpus and are inserted into the metacarpal and first phalanx of the thumb (flexor brevis pollicis, opponens pollicis, abductor pollicis brevis, adductor pollicis) . A similar set of muscles is grouped about the metacarpal of the little finger (abductor digiti quinti, opponens digiti quinti, flexor brevis digiti quinti) . These sets of muscles give rise respectively to the thenar and hypothenar eminences. Between the metacarpals two sets of interosseous muscles arise; a volar, adductor toward the middle finger and a dorsal, abductor group. They are inserted into the sides of the bases of the first row of phalanges and into the extensor tendons. They also flex the first row of phalanges and extend the other two rows. From the tendons of the deep flexor muscle of the fingers, a series of lumbrical muscles extends to the radial sides of the extensor tendons. They flex the first row of phalanges and extend the other two. Over the thenar eminence there is a subcutaneous muscle, the palmaris brevis. The muscles of the hand are supplied by the ulnar nerve, with the exception of the two more radial lumbricals and the abductor, opponens, and flexor brevis of the thumb, which are supplied by the median nerve.
Fasciae. — The muscle fascise of the upper extremities are well developed. The deltoid and latissimus dorsi are contained in a fascial sheet which extends between them. The deeper muscles which arise from the scapula are covered by strong fascia. Of the pectoral muscles the pectorahs major is covered by a delicate fascia, while the subclavius and pectoralis minor are contained within the dense cosio-coracoid membrane (fig. 358) which extends into the fascia covering the axillary fossa. The latter (fig. 359), is thin and is intimately fused to the tela subcutanea. The muscles of the arm are enveloped in a cylindrical sheath which in the lower half of the arm is united to the humerus by intermuscular septa.
In the forearm near the wrist and on the back of the hand the tela subcutanea contains little fat. The antibrachial fascia forms a cylindrical enclosure for the muscles of the forearm. Near the wrist it becomes strengthened dorsally to form the dorsal ligament of the carpus (posterior annular ligament). This ligament converts the grooves on the back of the radius into canals for the tendons of the extensors of the wrist and fingers. On the back of the hand and fingers the fascia is intimately connected with these tendons. On the volar side near the wrist the fascia is strengthened to form the volar hgament of the carpus. Beneath the ligament hes the transverse hgament of the carpus which extends from the pisiform and hamate bones to the tuberosities of the navicular and greater multangular bones. It completes an osteo-fibrous canal for the tendons of the long flexors of the fingers. On the palm of the hand the fascia is firmly bound to the bones by intermuscular septa, which separate the thenar and hypothenar regions from a central palmar region. On the volar sides of the fingers the fascia forms the vaginal ligaments of the flexor tendons.
The deltoid (fig. 355) is a large, shield-shaped muscle which covers the shoulder. It arises from the spine of the scapula, the acromion, and lateral third of the clavicle and is inserted into the deltoid tubercle of the humerus. It abducts the arm.
The teres minor, infra- and supraspinatus form a group of muscles (fig. 363) which arise from the back of the scapula, pass over the capsule of the shoulderjoint, to which their tendons are adherent, and, under cover of the deltoid, are inserted into the top and the dorsal margin of the great tubercle of the humerus. The band-like teres minor arises from the upper two-thirds of the axillary border of the scapula, and has the lowest insertion on the tubercle. The triangular infraspinatus (fig. 363) arises from the whole infraspinous fossa except the axillary border, and is inserted above the teres minor. The pyramidal supraspinatus (fig. 363) arises under cover of the trapezius from the supraspinous fossa, and has the highest insertion on the tubercle. The teres minor, supraspinatus and infraspinatus act as lateral rotators of the arm, the supraspinatus also as an abductor.
Pectoralis major
extends distally from this on the medial side of the intertubercular (bicipital) groove. The latissimus dorsi (figs. 355, 356) is a large, flat, triangular muscle, which arises from an aponeurosis covering the lumbar and the lower half of the thoracic regions of the back and from the posterior part of the iliac crest, and is inserted into the intertubercular (bicipital) groove. The teres major (figs. 355, 356) is a thick, ribbon-shaped muscle which arises from the dorsal surface of the inferior angle of the scapula and is inserted behind the latissimus dorsi into the distal two-thirds of the crest of the small tubercle of the humerus. The subscapularis (fig. 355) is a thick, triangular muscle which extends from the subscapular fossa to the small- tubercle of the humerus. These muscles adduct the arm and rotate it medialward. The latissmus dorsi is also the chief extensor of the arm.
Near their humeral attachments these two groups of muscles are separated below by the long head of the triceps. The supraspinatus is separated from the subscapularis by the base of the coracoid process and by the intertubercular (bicipital) groove. The tendons of the latissimus dorsi, teres major, and subscapularis are crossed ventrally by the main vessels and nerves of the arm and by the short head of the biceps and the coraco-brachialis.
The supra- and infraspinatus muscles are supplied by the suprascapular nerve. The deltoid and the teres minor are supplied by the axillary (circumflex). The subscapularis, the teres major, and the latissimus dorsi are supplied by subscapular nerves. That to the latissimus dorsi is called the dorsal thoracic nerve.
DELTOIDS us 365
The deltoid in many of the mammals and the lower vertebrates is represented by separate scapulo-humeral and cleido-humeral portions. The cleido-mastoid in some mammals is continued into the deltoid. The teres minor, which is innervated by the same nerve, may be looked upon as a derivative of the deltoid, although in man it is anatomically more intimately connected with the infraspinatus. The teres major may be looked upon as a speciahsed portion of the more primitive latissimus dorsi. The comparative anatomy of the shoulder muscles throughout the vertebrate series is a somewhat intricate subject, owing to the great variations exhibited in the form and attachment of the shoulder girdle.
The muscles of this group show more or less marked resemblances to certain muscles of the lower limb. The deltoid and the teres minor probably represent the tensor fascise latEe, the gluteal fascia, and the upper part of the gluteus maximus; the latissimus dorsi and teres major, the lower portion of the gluteus maximus; and the subscapularis, the gluteus medius and minimus, and the piriformis. The subscapular and axillary nerves, which supply the arm muscles mentioned, therefore represent in the main the nerves to the gluteal muscles, and the gluteal branch of the posterior cutaneous nerve of the thigh. The infraspinatus muscle probably represents the ihacus; the supraspinatus possibly the pectineus muscle of the lower limb.
The tela subcutanea covering the regions occupied by these muscles contains considerable fat. In most regions it is not readily separable into two distinct layers. In the neighbourhood of the shoulder-joint it is adherent to the underlyingmusculatureand the axillary fasciie. Over the acromion there is a well-marked subcutaneous bursa, bursa subcutanea acromialis.
Muscle fasciae. — The deltoid and latissimus dorsi muscles are throughout the greater part of their extent superficially placed. They are covered by an adherent fascial layer, which, above, is attached to the clavicle and to the spine of the scapula. VentraUy it is continued over and fuses with the fascia covering the pectoralis major, serratus anterior, and external oblique muscles. On the back it extends as a thin sheet between the dorsal margin of the deltoid and the upper margin of the latissimus dorsi, and is continued dorsaUy into the fascial investment of the rhomboid muscles. The lateral fascial extension of the trapezius becomes fused to the dorsal surface of this sheet. Toward the armpit the fascial investment of the deltoid and latissimus dorsi muscles is continued into the axillary fascia, and on the back of the arm it is continued into the fascial investment of the triceps.
The supraspinatus muscle lies beneath the trapezius. It is covered by a dense adherent fascial layer which is separated from the trapezius by loose connective tissue which usually contains a considerable amount of fat.
The infraspinatus and the two teres muscles lie beneath the musculo-fascial layer composed of the deltoid, the latissimus dorsi, and the fascial sheet described above. Each of the three muscles has a special fascial investment which is bound to the scapula about the region of attachment of the muscle to the bone. Where two of the muscles adjoin, their fasciae gives rise to intermuscular septa. Septa of this nature are found between the infraspinatus and each of the teres muscles, and between the teres minor and the teres major. The intermuscular septum between the infraspinatus and teres minor muscles is often incomplete. The fascia covering the teres major is so delicate as hardly to deserve the name, except near the origin of the muscle. Near the spine the fascia covering the deep surface of the deltoid is often fused to that covering the infraspinatus.
The subscapularis muscle is invested by a moderately dense fascia which is bound to the scapula along the periphery of the attachment of the muscle. For a short distance this fascia is fused with the fascial investment of the teres major near the origin of the latter muscle, so that an intermuscular septum is formed. From the ventro-lateral margin of the fascia covering the subscapularis muscle a sheet of fascia is continued below the axillary fascia into the fascia covering the serratus anterior (magnus).
The deltoideus (figs. 355, 356, 360). — Origin. — Fleshy from the lateral border and upper surface of the acromion and from the ventral border and upper surface of the lateral third of the clavicle, and tendinous from the spine of the scapula. Some fibre-bundles also at times arise from the deep fascia of the muscle where it overlies and is fused to the fascia of the infraspinatus muscle near the spine.
Structure. — In structure the deltoid muscle is complex. Three portions may be recognised: — a clavicular, an acromial, and a spinous. The first and last are composed of long fibre-bundles which take a slightly converging course and are inserted by aponeurotic tendons respectively on the front and back of the V-shaped area of insertion of the muscle. The acromial portion, on the other hand, is multipenniform in composition. Four or five tendinous expansions descend into the muscle from the acromion, and three up into the muscle from the tendon of insertion. From the acromion and from the descending tendinous processes fibre-bundles run to be inserted on the sides of the ascending processes and into the tendons of insertion of the clavicular and spinous portions of the muscle.
N eroe-supply . — The axillary (circumflex) nerve passes across the costal surface of the muscle near the tendon of insertion and gives off rami which enter lateral to the middle of the muscle. The nerve fibres are derived from the (foiu-th), fifth, and sixth cervical nerves.
TERES MINOR 367
horizontal position. When the clavicular and acromial parts act, the arm is raised and flexed (brought forward toward the chest). When the acromial and spinous parts act, the arm is raised and extended (carried toward the back), but in this instance the arm is not brought to a level with the shoulder-joint, but only about 45° from the hanging position. The inferior part of the serratus anterior and the trapezius act in conjunction with the deltoid in abduction. Abduction is greatest when the arm is rotated lateralward. The ventral portion rotates the arm medially, the dorsal portion laterally. When the arm is fixed, the deltoid tends to carry the inferior angle of the scapula toward the spinal column and away from the thorax.
Relations. — On its ventral border the deltoid is in contact with the pectoralis major muscle. Near the clavicle the cephalic vein and a small artery pass between the two muscles. Its dorsal border is continued into a dense fascial sheet which overlies the infraspinatus muscle. Its tendon of insertion passes between the biceps and triceps muscles. The deltoid overhes the coracoid process and upper extremity of the humerus, the coraco-olavicular and coraco-acromial hgaments, and the insertions of the supraspinatus, infraspinatus, and teres minor muscles, the origins of the biceps and coraco-brachiahs, and a part of the long and lateral heads of the triceps. Beneath it run the posterior circumflex artery and axillary (circumflex) nerve.
Variations. — The clavicular portion is frequently separate from the rest of the muscle. The three portions may be distinctly separate — a condition normal in some of the lower mammals. The clavicular and acromial portions have been found missing. The deep portion of the muscle may be separated as a distinct layer and inserted either into the capsule of the joint or into the humerus. Accessory fasciculi may pass into the muscle from the fascia over the infraspinatus and from the vertebral and axillary borders of the scapula. Not infrequently fasciculi are continued into the muscle from the trapezius — a condition normal in animals with ill-developed clavicles. An accessory tendon of insertion may extend to the radial side of the forearm. Bundles of fibres from the axillai'y border of the scapula have been seen to cross the deep sm^face of the deltoid and be inserted into the deltoid fascia. The deltoid may be fused with neighbouring muscles, the pectoralis major, trapezius, infraspinatus, brachialis, brachio-radiahs.
The teres minor (fig. 363). — Origin. — From the upper two-thirds of the axillary border of the infraspinous fossa, and from the septa lying between it and the infraspinatus on the one side and the teres major and subscapularis on the other. The origin is in part fleshy, in part from an aponeurotic band on its ventral surface toward the subscapularis muscle.
Structure and insertion. — The fibre-bundles from this origin take a slightly converging course toward a tendon of insertion which extends for some distance on the dorsal surface of the muscle. The muscle is adherent to the capBule of the joint, and terminates on the inferior of the three facets of the great tubercle of the humerus and the postero-lateral aspect of that bone for two or three centimetres below the facet.
Nerve-supply. — From a branch of the axillary (circumflex) nerve which enters the muscle on its lateral margin about midway between its extremities. A 'ganglion' is usually found upon this nerve. A branch from the nerve to the teres major has also been reported. The nerve fibres are derived from the fifth cervical nerve.
flexor when the arm is down and an extensor when it is abducted. It is also an adductor.
Relations. — The muscle is in part covered by the deltoid. Ventrally it enters into relations with the long head of the triceps, the teres major, and the subscapularis. Superiorly, the circumflex (dorsal) scapular vessels run between it and the axillary border of the scapula.
INDICATED IN THE DIAGRAM.
In the neighbourhood of the brachial plexus in each section some of the adipose and lymphatic tissue has been removed. In section B the fascia covering the apex of the axillary fossa is thus revealed from above, a and 6 in the diagram indicate the regions through which pass sections A and B, fig. 351 (p. 352); a' and b', the regions through which pass sections A and B, fig. 362 (p. 375).
1. Aorta. 2. Arteria brachiaUs. 3. A. circumflexa scapulae (dorsahs scapulse). 4. A. carotis communis. 5. A. mammaria interna. 6. A. subclavia. 7. A. thoracahs lateralis (long thoracic). 8. Costa I. 9. Costa II. 10. Costa III. 11. Costa IV. 12. Costa V. 13. Costa VI. ' 14. Clavicle. 15. Fibrocartilago intervertebrahs (intervertebral disc). 16. Fascia axillaris. 17. Fascia cervicalis (superficial layer). 18. Middle layer. 19. F. coraco-clavicularis. 20. F. lumbo-dorsahs. 21. Fascia of posterior serrati. 22. Humerus. 23. Medulla spinalis (spinal cord). 24. Musculus biceps — a, long head; 6, short head; c, tendon of short head. 25. M. coraco-brachialis. 26. M. deltoideus. 27. M. infraspinatus. 28. M.iho-costahsdor^i (accessorius). 29.M.intercostalesexterni. 30. M.intercostales interni. 31. M. latissimus dorsi, tendon. 32. M. levator costs. 33. M. longissimus dorsi. 34. M. longus oolU. 35. M. pectorahs major. 36. M. pectorahs minor. 37. M. platysma. 38. M. rhomboideus major. 39. M. scalenus anterior. 40a. M. serratus anterior. 406, M. serratus posterior superior. 41. M. sterno-mastoideus. 42. M. cleido-mastoideus. insertion. 43. M. sterno-hyoideus. 44. M. sterno-thyreoideus. 45. M. subclavius. 46. M. subscapularis. 47. M. teres major. 48. M. teres minor. 49. M. trapezius. 50. M. transverso-spinales. 51. M. triceps — a, long head; 6, lateral head. 52. Nervus axillaris 53. N. cutaneus antebrachii medialis (internal cutaneous). 54. a-e, Nn. intercostales I-V. 55. N. medianus. 56. N. phrenicus. 57. N. musculocutaneus. 58. N. radiaUs (musoulo-spiral). 59. N. recurrens. 60. N. subscapularis. 61. Sj'mpathetic trunk. 62. N. thoracalis anterior. 63. N. thoracalis longus. 64. N. thoracodorsaUs (long subscapular). 65. N. ulnaris. 66. N. vagus. 67. CEsophagus. 68. Plexus brachialis — a, lateral fasciculus; 6, medial; c, posterior. 69. Scapula. 70. Sternum. 71. Trachea. 72. Venae brachiales. 73. V. cephaUca. 74. V. jugularis anterior. 75. V. jugularis inferior. 76. V. subclavia. 77. Vertebra I. 78. Vertebra II. 79. Vertebra III. 80. Vertebra IV. 81. Vertebra V. 82. Vertebra VI.
reported an isolation of a special fasciculus to the subtubercular attachment.
The infraspinatus (fig. 363). — Origin. — From the vertebral three-fourths of the infraspinous fossa, from the under surface of the spine, from the enveloping fascia and from intermuscular septa between it and the two teres muscles.
Structure and insertion. — The fibre-bundles converge toward the lateral angle of the scapula to be attached to a deep-seated tendon which is adherent to the capsule of the joint and is attached to the middle facet of the great tubercle. The fibre-bundles arising from the inferior surface of the spine and the fascia near this form a distinct fasciculus which descends on and covers the tendon of insertion.
Nerve-supply. — From the suprascapular nerve, which passes beneath the supraspinatus muscle and enters the deep surface of the infraspinatus in the lateral part of the midde third of its upper margin. From here rami spread out toward the vertebral border of the muscle and toward the humeral insertion. The nerve fibres are derived from the fifth and sixth cervical nerves.
Action. — This muscle is the chief lateral rotator of the arm, a movement that can be carried through 90°. The upper part of the muscle is an abductor, the lower part an adductor of the arm. The muscle is also a flexor.
Relations. — The deltoid and trapezius, and sometimes the latissimus dorsi muscles, cover a portion of the dorsal surface. Over most of it extends the complex fascia described above. Laterally it adjoins the teres minor and major muscles. Under the muscle he the transverse (suprascapular) and circumflex (dorsal) scapular vessels.
Variations. — These are rare, aside from a greater or less independence of the bundles arising from the spine and a greater or less complete fusion with the teres minor. A fasciculus has been seen extending to the muscle from the deltoid.
flexor. It keeps the head of the humerus in place during abduction of the arm.
Relations. — The muscle is covered by the trapezius, the acromion, and the coraco-acromial hgament. Beyond the base of the spine of the scapula it comes into contact with the infraspinatus muscle. Beneath the muscle pass the suprascapular nerve and transverse scapular (suprascapular) vessels.
The latissimus dorsi (figs. 355, 356, 387, 388). — Origin. — (1) From an aponeurosis attached to the spines and interspinous ligaments of the five or six last thoracic and the upper lumbar vertebra, to the lumbo-dorsal fascia, and to the posterior third of the external lip of the crest of the ilium; (2) from the external surface and upper margin of the last three or four ribs by muscular slips which interdigitate with those of the external oblique. In the lumbar region the aponeuroses of the right and left muscles are connected by fibrous fascicuh which cross the mid-dorsal line above the supraspinous ligament.
Structure and insertion. — From this extensive area of the origin fibre-bundles converge toward the tendon of insertion. In the region of the dorsal wall of the axillary fossa the muscle is concentrated into a thick, ribbon-like band which winds about the teres major and passes to the ventral surface of that muscle. As this takes place the fibre-bundles become apphed to each surface of a flat tendon, which, after emerging from the muscle, is six to eight cm. long and three to five cm. broad, and is inserted into the ventral side of the crest of the lesser tubercle of the humerus and into the depth of the intertubercular (bicipital) groove immediately ventral to the tendon of the teres major. With this it is more or less closely bound, although between the tendons there lies a serous bursa. Some of the fasciculi of the tendon extend to the crest of the greater tubercle. Frequently a tendon slip passes from the inferior margin of the tendon to the tendon on the posterior surface of the long head of the triceps or into the brachial fascia (see lalissirno-condyloideus, p. 379).
Like the teres major, with which it is closely associated, the latissimus dorsi muscle undergoes a torsion between its origin and its insertion, so that the dorsal surface of the muscle is continued into the ventral surface of the tendon and the most cranially situated of the fibrebundles are most distally attached to the humerus, and vice versa. The muscle either directly or through its fascial extension is often adherent to the inferior angle of the scapula.
Nerve-supply. — From the dorsal thoracic (long subscapular) nerve (from the sixth, seventh and eighth cervical nerves) . This nerve, which may arise in conjunction with the axillai'y nerve, passes to the deep surface of the muscle in the lower part of the axilla, and here gives rise to rami which diverge as the muscle expands toward its tendons of origin. Though soon embedded in the muscle substance, two main branches may be followed for a considerable distance near the deep surface of the muscle. One usually extends near the lateral, the other near the superior, border of the muscle, and from these large rami pass into the intervening region. Branches of the dorsal thoracic artery and vein accompany the nerve.
Action. — With the trunk fixed, the latissimus dorsi draws the raised arm down and backward and rotates it medialward (swimming movement). When the arm is hanging by the side, the action of the muscle is on the scapula. The upper third of the muscle draws the scapula toward the spine, the inferior two-thirds depress the shoulder. When the humerus is fi^ed, the latissimus serves to lift the trunk and pelvis forward, as in climbing. It also aids in forced inspiration through its costal attachments.
BURSJE 369
^Relations. — The trapezius covers a small portion of the muscle in the mid-thoracic region of the back. Over a large area it is subcutaneous, and its fascial investment is adherent to the skin. As it winds about the teres major its tendon comes to lie behind the coraco-brachialis muscle. The main nerves and vessels of the arm here pass across its ventral surface. The muscle covers in part the rhomboideus major, the infraspinatus, teres major, serratus posterior inferior, the lower ribs, the external intercostal muscles, the dorsal border of the external and internal oblique muscles, and the lower dorsal part of the serratus anterior (magnus).
Variations. — It may show considerable variation in the extent of its fleshy portion and in the attachment of its aponeurosis to the vertebral column, crest of the ilium, the ribs, and the scapula. Its origin may be merely from the ribs. It maj' be divided into separate fasciculi. Frequently a fasciculus arises from the inferior angle of the scapula. The muscle is often intimately united to the teres major. For an account of the muscular slip which extends from the latissimus dorsi across the axillary fossa to the tendon of the pectoralis major near the intertubercular (bicipital) groove see the latter muscle (p. .374); and for the slip continued from the tendon of the latissimus dorsi to the olecranon see the Triceps Muscle (p. .379).
The teres major (figs. 356, 388). — Origin. — Directly from the dorsal surface of the inferior angle of the scapula and from the septa which lie between this muscle and the subscapularis, teres minor, and infraspinatus muscles.
Insertion. — For about five or six cm. from the lower border of the small tubercle of the humerus, along the medial lip of the intertubercular (bicipital) groove. ProximaUy the fibrebundles are attached directly to the tubercle; more distally the attachment is by means of a flat tendon which extends for some distance on the dorsal surface of the muscle.
Structure. — The nearly paraOel fibre-bundles pass upward in a spiral direction so that the muscle undergoes a torsion on its axis. The fibre-bundles which have the highest attachment to the scapula have the lowest humeral attachment, and vice versa.
acts as a medial rotator and as an extensor.
Relations. — Dorsally the muscle is covered by the latissimus dorsi and by the fascia which extends from this muscle to the deltoid and rhomboid muscles. It is also crossed by the long head of the triceps. Its lower border and ventral surface are largely covered by the latissimus dorsi and its tendon. Its upper border helps to bound a triangular space the other sides of which are the borders of the scapula and the humerus. In front lies the subscapularis, and behind, the teres minor. Across this space passes the long head of the triceps. Lateral to this head lie the humeral circumflex vessels and axillary (circumflex) nerve; and medial, the circumflex (dorsal) scapular artery.
Variations. — The teres major may be connected with the latissimus dorsi by a fasciculus, or it may be fused with that muscle or its tendon. Slips have also been seen extending to the triceps and into the fascia of the arm. The muscle is rarely absent.
The subscapularis (figs. 356, 388). — Origin. — The fibre-bundles spring — (1) directly and by means of tendinous bands from the costal surface of the scapula, except near the neck and at the upper and lower angles; and (2) from intermuscular septa between it and the teres major and teres minor muscles.
mediately below this.
Structure. — The fibre-bundles arising from the tendinous bands attached to the bone converge upon several tendinous laminee which extend into the muscle from the tendon of insertion, thus forming small pennif orm fasciculi. The fibre-bundles arising directly from the bone converge toward the extremities of the tendinous lamina;, thus forming triangular bundles interdigitating with the penniform fasciculi. The fasciculus which arises highest on the axillary border goes directly to the humerus.
Nerve-supTply. — By two or three subscapular branches from the back of the brachial plexus. One or more of these may arise in association with the axillary (circumflex) nerve. From the main nerves rami spread out to enter the ventral surface of the muscle near the junction of the lateral and middle thirds. The nerve fibres come from the fifth and sixth cervical nerves.
Action. — It is the chief medial rotator of the arm. It strengthens the shoulder-joint by drawing the humerus against the glenoid cavity. It is an extensor when the arm is at the side, a flexor when the arm is abducted. The upper portion of the muscle, however, acts as a flexor in both positions. The upper part acts as an abductor but when the arm is abducted the muscle is an adductor.
Relations. — Ventrally it forms the greater part of the posterior wall of the axillary fossa, and enters into relation with the serratus anterior (magnus) and the combined tendon of the coraco-brachiaUs and biceps. On it lie the axillary vessels, the brachial plexus, and numerous lymph-vessels and glands. At its lateral border lie the teres major, the humeral cu-cumflex vessels, axillary (circumflex) nerve, and circumflex (dorsal) scapular vessels. Behind it he the long head of the triceps and the teres minor muscle.
Variations. — It may be divided into several distinct segments. A fasciculus may be sent to the tendon of the latissimus dorsi and another to the brachial fascia. The subscapularis minor arises from the axillary border of the scapula and is inserted into the articular capsule (capsular hgament) of the shoulder-joint or into the crest of the lesser tubercle of the humerus.
clavicle and the deltoid muscle.
B. m. subscapularis. — Between the glenoid border of the scapula and the subscapularis muscle. Communicates with the joint cavity. A small portion of this bursa may be isolated adjacent to the base of the coracoid process (6. subcoracoidea) .
minor, and the subclavius. Of these, the largest and most superficial is the
Fig. 358. — Deep Fascia of the Breast. (After Eisler). The Pectoralis Major Has Been in Large Part Removed. 1, Deltoid; .2, Pectoralis Major, Abdominal Past; 3, Pectoralis. Minor; 4, Coraco-Brachialis.
triangular pectoralis'major (fig. 360), which arises from the second to the sixth ribs, the sternum, and the medial half of the clavicle and is inserted into the crest of the greater tubercle of the humerus (pectoral ridge). Its lateral margin adjoins the ventral margin of the deltoid. Beneath this muscle the much smaller triangular pectoralis minor (fig. 388) extends from near the ends of the second, third, fourth, and fifth ribs to the tip of the coracoid process, while the small subclavius (fig. 361) extends from the first rib upward and lateralward to the clavicle.
Of the muscles included in this group, the two pectoral muscles are morphologically the most closely related. They receive a nerve-supply from the same set of nerves, the anterior thoracic With them the subclavius, which has a separate nerve of its own, is closely associated. Cor-
F ASCIIS
responding musculatui-e, although variously modified in different forms, is found tlii'oughout the vertebrate series. In the lower forms it se"ems to be differentiated directly from the segmental trunk musculature and secondarily attached to the shoulder girdle, like the superficial and deep musculature of the shoulder girdle previously described. In man, however, the muscle mass from which these muscles arise is at all times in intimate union with the skeleton of the upper limb, and the nerves which supply it are in much more intimate union with the brachial plexus than are those of the shoulder-girdle muscles. For these reasons the three muscles are classed with the intrinsic muscles of the arm. They have no certain representatives in the lower hmb, although the clavicular portion of the pectoralis major is considered by some to represent certain adductor muscles of the thigh. Possibly they correspond in their embryonic origin with the obturator internus group of the lower hmb.
In many of the mammals a subcutaneous muscle arises from the pectoral muscle mass and extends over the axUla and the trunk. In man this musculature is frequently represented by abnormal shps of muscles, of which the 'axillary arch' and possibly the 'sternalis' are representatives. A list of some of the abnormal muscles which are innervated from the anterior thoracic nerves and are evidently derivatives of the pectoral muscle mass is given at the end of this section
In the tela subcutanea of the pectoral region the mammary gland is embedded between two layers which ensheath the gland and are connected by dense fibre-bands. To a greater or less extent the platysma extends into the tela of this region from above the clavicle.
Muscle fasciae. — The pectorahs major is invested with a thin, adherent membrane, fascia pectoralis, attached to the clavicle and the sternum and continued into the fascial investment of the external obUque, the serratus anterior (magnus), and the deltoid muscles, and in to the axillary fascia. More important is the coraco-clavicular (costo-coracoid) fascia fig. 358. This arises from two fascial sheets which invest the subclavius muscle and are attached to the clavicle. From the inferior margin of this muscle the membrane is continued to the superior margin of the pectoralis minor. Between the coracoid process and the first costal cartilage it is strengthened to form the costo-coracoid ligament. Between this and the pectorahs minor it is thin. At the superior margin of this muscle it again divides to form two adherent fascial sheets, which, at the axillary margin of the muscle, once more unite to form a fii'm membrane continued into the fascial investment of the coraco-brachiahs and short head of the biceps and into the axiUai'y fascia. Above, dorsally, the membrane is adherent to the sheath of the axillary vessels and nerves.
dorsi, teres major, and subsoapularis muscles behind; by the subscapularis muscle toward the joint; and by the serratus anterior (magnus) toward the thoracic wall. In the groove between the coraco-brachiaUs and the subscapularis and tendons of the latissimus dorsi and teres major muscles run the main nerves and vessels of the arm. These are surrounded by a considerable amount of connective tissue in which numerous blood- and lymph-vessels, lymph-nodes, nerves, and masses of fat are embedded.
External intercostal
Over this connective tissue the fascia covering the musculature of the neighbouring portion of the shoulder and thorax is continued into the fascia covering the musculature of the medial side of the arm. Thus the fascia covering the pectoralis minor, the coraco-clavicular fascia, strengthened by a reflection of the fascial investment of the pectorahs major and deltoid musclesis continued across the ventral margin of the arm-pit into the fascia which covers the coracobrachialis and biceps muscles in the arm. Similarly, dorsally, the fascia Covering the latissimus dorsi and teres major is continued over the arm-pit into that covering the long head of the triceps in the arm. The ventral is connected with the dorsal fascia by a thin membrane which is adherent to the connective tissue filling the axillary space and to the subcutaneous tissue. On the trunk this membrane, the fascia axillaris, becomes fused below the axillary fossa with the fascia of the serratus anterior (magnus). In the arm it becomes fused with the fascia over the biceps muscle. Owing to its adherence to the skin and the connective tissue of the axillary fossa, investigators have dissected out and figured the axillary fascia in different ways.
The pectoralis major (fig. 360). — Origin. — (1) From the medial half of the clavicle; (2) from the side and front of the sternum as far as the sixth costal cartilage; (3) from the front of the cartilages of the second to the sixth ribs; and (4) from the upper part of the aponeurosis of the external oblique where this extends over the rectus abdominis muscle. The costal origin may in part take place from the osseous extremities of the sixth and seventh ribs.
Insertion. — Crest of the greater tubercle (outer lip of the bicipital groove) of the humerus from the tubercle to the insertion of the deltoid (fig. 174). Some of the tendon fibres are also continued into the tendon of the deltoid and adjacent fibrous septa and into the fibrous lining of the intertubercular sulcus.
Structure. — The muscle is divisible into a series of overlapping layers spread out hke a fan. Of these, the clavicular portion forms the most cranial and superficial layer, and the portion of the muscle springing from the aponeurosis of the external oblique, the most caudal and deepest layer. This last layer has a special tendon, while the other layers are inserted into a combined
Neroe-supply. — From the external and internal anterior thoracic nerves, branches of which enter the sterno-costal portion of the muscle about midway between the tendons of origin and insertion, and the clavicular portion in the proximal third. The nerve fibres are derived from the (fifth), si.xth, seventh and eighth cervical and first thoracic nerves.
Action. — With the thorax fixed, the muscle adducts and flexes the arm and rotates it medialward. The clavicular portion draws the arm forward, upward, and medialward; the sternocostal portion draws the arm downward, medialward, and forward. When the arm is pendent, the upper portion elevates, the lower depresses, the shoulder. With the arm fixed, the muscle draws the chest upward toward it. It is of value in forced inspii'ation.
Relations. — It lies over the coracoid process, the subclavius, pectoralis minor, intercostal, and serratus anterior (magnus) muscles, the coraco-clavicular (costo-coracoid) fascia, and the thoraco-aoromial vessels. It forms the main part of the ventral wall of the axillary fossa, and laterally it enters into relation with the deltoid, biceps, and coraco-brachialis muscles.
Variations. — In considering variations the muscle may be looked upon as composed of four portions — a clavicular, a sternal, a costal, and an abdominal, the last being that portion which arises from the aponeurosis of the external obhque. These portions vary in the extent of their attachments and in the degree of separation which they present. The abdominal portion may extend to the umbilicus. Huntington considers this portion a derivative of the pannicular muscle of the lower mammals. On the sternum the muscles of the two sides may decussate across the middle line. The sterno-costa! portions of the muscle are more frequently deficient or missing than the clavicular, but in rare cases the entire muscle is absent. The clavicular portion of the muscle may be fused with the deltoid. The sterno-costal may extend laterally to the latissimus dorsi. There may be an intimate fusion of the abdominal portion with the rectus abdominis or the external oblique. Sometimes a slip may run from the pectoralis major to the biceps, the pectoralis minor, coracoid process, capsule of the joint, or brachial fascia.
Nerve-supply. — From the internal anterior thoracic nerve which enters the upper part of the middle third of the deep surface by several branches. Some of the branches extend through to the pectoralis major. The nerve fibres arise from the seventh and eighth cervical nerves.
Action. — When the thorax is fixed, the pectoraUs minor pulls the scapula forward, the lateral angle of the bone downward, and the inferior angle dorsalward and upward. When the scapula is fixed, the muscle aids in forced inspiration.
of the chief nerves and vessels of the arm is adherent to its enveloping fascia.
Variations. — The origin may extend to the sixth rib or may be reduced to one or two ribs. In the primates below man the insertion of the muscle takes place normally into the humerus. In man its insertion may be continued (in more than 15 per cent, of bodies — Wood) over the coracoid process to the coraco-acromial or coraco-humeral ligaments, to the tendon of the subscapularis muscle, or to the great tubercle of the humerus. It may be divided into two superimposed fasciculi. Fasciculi may extend from the muscle to the subclavius or the pectoralis major.
cartilage near their junction.
Structure and insertion. — The fibre-bundles arise in a penniform manner from the tendon of origin which extends for some distance along the lower border of the muscle. They are inserted in a groove which lies on the lower sm'face of the clavicle between the costal tuberosity and the coracoid tuberosity. The medial fibre-bundles are inserted directly, the lateral by a strong tendon.
subclavian vessels and the brachial plexus.
Variations. — It may be replaced by a ligament or by a peotoralis minimus muscle (see below). It may be doubled or may be inserted into the coracoid process, ooraco-aoromial hgament, the acromion, or the humerus. The subclavius posticus arises near the subolavius, passes backward over the subclavian vessels and brachial plexus and is inserted into the cranial margin of the scapula near the base of the coracoid process.
Abnormal Muscles of the Pectoral Group
The following muscles are usually innervated by the anterior thoracic nerves and are probably generally abnormal derivatives of the pectoral mass. Frequently they represent muscles normally found in lower mammals.
The sternalis. — A flat muscle somewhat frequently seen on the surface of the pectoralis major, usually nearly parallel to the sternum. It arises from the sheath of the rectus and from some of the costal cartilages (third to seventh) and terminates on the sterno-oleido-mastoid, on the sternum, or on the fascia covering the pectoraUs major. When present on both sides, the two muscles may be fused across the sternum. This muscle is found in 4 per cent, of normal individuals and 48 per cent, of anencephalic monsters. (Eisler.) Rarely, corresponding muscle slips have been found innervated by the intercostal nerves. These probably represent remains of a thoracic 'rectus' muscle.
The pectoro-dorsalis (axillary arch). — This muscle in its most complete form extends from the tendon of the pectoralis major over the axillary fossa to the tendon of the latissimus dorsi, to the fascia covering the latissimus dorsi, to the teres major or even more distaUy. It may, however, be more or less fused with either of the last two muscles mentioned, and it presents a great variety of forms. It may extend from the latissimus dorsi to the brachial fascia over the coraco-brachialis or biceps, to the long tendon of the biceps, to the axillary fascia, to the axillary margin of the pectoralis minor, or to the coracoid process, etc. It is found in about 7 per cent, of bodies. (Le Double.) When supplied from the anterior thoracic nerves, it probably represents a portion of the thoraco-humeral subcutaneous (pannicular) muscle of the lower primates. It is also sometimes supplied by the medial brachial cutaneous or the intercostobrachial (humeral) nerve and frequently is partly or wholly supplied by the dorsal thoracic (long subscapular) nerve. The part of the muscle supphed by the dorsal thoracic nerve is probably derived from the latissimus dorsi musculature.
The costo-coracoideus. — A muscular slip which arises from one or more ribs or from the aponeurosis of the external oblique between the pectoralis major and latissimus dorsi muscles, and is inserted in the coracoid process.
The chondro-humeralis (epitrochlearis). — This is a slip which springs from one or two rib cartilages or from the thoraco-abdominal fascia beneath the pectoralis major, or from its lower border or tendon, and extends on the medial side of the arm to the intertubercular (bicipital) groove, the brachial fascia, the intermuscular septum, or the medial epicondyle. It is found in 12 to 20 per cent, of bodies (Le Double), and occurs normally in many of the lower mammals.
The muscles included in this section are the triceps and anconeus, coracobrachialis, biceps, and brachialis. The triceps and anconeus (fig. 363) constitute a mass of musculature extending along the back of tlie arm from the scapula and humerus to the olecranon of the ulna. The coraco-brachialis, biceps, and brachialis (figs. 364, 365) constitute a similar mass of musculature extending along the front of the arm from the scapula and the humerus to the humerus, and to the radius and ulna near the elbow. In the upper half of the arm the two groups are separated on the lateral side of the arm by the deltoid, pectoralis major, teres minor, supra- and infraspinatus muscles, and by the greater tubercle of the humerus. On the medial side they are separated the by chief nerves and blood-
1. Arteria brachialis. 2. Bursa subcutanea olecrani. 3. Fascia brachiahs. 4. Humerus. 5. Musculus anconeus. 6. M. biceps — a, long head; b, short head; c, tendon of insertion. 7. M. brachiahs. 8. M. brachio-radialis. 9. M. coraco-brachialis. 10. M. deltoideus. 11. M. e.xtensor carpi radiahs brevis. 12. M. extensor carpi radialis longus. 13 M. extensor digitorum communis. 14. M. flexor carpi radialis. 15. M. flexor carpi ulnaris.. 16. M. flexor digitorum subhmis. 17. M. flexor digitorum profundus. 18. M. palmaris longus. 19. M. pronator teres. 20. M. triceps — a, lateral head; b, long head; c, medial head. 21a. N. cutaneus antibrachii medialis (internal cutaneous). 216. N. cutaneus antibrachii dorsalis. 22. N. musculo-cutaneus. 23. N. medianus. 24. N. radialis^a, muscular branch. 25. N. ulnaris. 26. Lymphatic gland. 27. Olecranon. 28. Septum intermusculare laterale. 29. Septum intermusculare^mediale. 30. Vena cephalica. 31. V. basilica. 32. Vv. brachiales.
vessels of the arm and by the tendons of the latissimus dorsi, teres major, and subscapularis muscles. In the distal half of the arm they are separated medially by the medial intermuscular septum (described below) and by the medial epicondyle and the ulno-volar group of muscles of the forearm. On the lateral side of the arm they are separated by the lateral intermuscular septum, by the lateral epicondyle, and by the brachio-radialis and the extensor muscles of the forearm which take origin from the lateral epicondyle.
sections in fig. 362.
The tela subcutanea of the arm is fairly well developed and contains a considerable amount of fat, especially near the shoulder. It is but loosely bound to the muscle fascia, except near the insertion of the deltoid, where the union may be more intimate.
Bursse. — B. subcutanea epicondyli lateralis. — Between the lateral epicondyle and the skin. Rare. B. subcutanea epicondyli medialis. — Between the medial epicondyle and the skin. Inconstant. B. subcutanea olecrani. — Between the olecranon process of the ulna and the skin. Nearly constant.
The brachial fascia forms a cylindrical sheath about the muscles of the arm. It contains circular and longitudinal fibres, the former being the better developed. The fascia is strong over the dorsal muscles, especially near the two epicondyles of the humerus. Proximally the fascia of the arm is continued into the axillary fascia and into the fascial investment of the pectoralis major, deltoid, and latissimus dorsi muscles; distally it is continued into the fascial investment of the forearm. It is intimately bound to the epicondyles and to the dorsal surface of the olecranon. It is separated by loose areolar tissue from the beUies of the muscles which it covers. From the tendons of the deltoid, pectoralis major, teres major, and latissimus dorsi muscles, however, fibrous bundles are continued into the brachial fascia. There are a number of orifices in the fascia for the passage of nerves and blood-vessels. Of these, the largest is that for the basilic vein and two or three large branches of the medial antibrachial (internal) cutaneous nerve. This lies on the ulnar margin of the arm in the lower third. On the radial margin lie the cephalic vein in a double fold of the fascia, orifices for branches of the musculocutaneous nerve, and more dorsally orifices for branches of the radial. From the fascia septa descend between the muscles which it invests. Of these septa, the most important are the medial and lateral intermuscular septa, which separate the dorsal group of muscles from the ventral in the distal half of the arm. The medial intermuscular septum is the stronger. It is attached to the medial epicondyle and to the medial margin of the humerus proximal to this, It is continued proximally into the tendon of insertion of the coraco-brachialis and the investing fascia of this muscle. Into it longitudinal bundles of fibres descend from the tendon. It separates the brachiaUs and pronator teres muscles from the medial head of the triceps. The lateral intermuscular septum is attached to the lateral epicondyle and to the lateral margin of the humerus. It is continued proximally into the dorsal surface of the tendon of insertion of the deltoid muscle, and into the septa between the deltoid and the triceps. It separates the triceps from the brachialis in the third quarter of the arm and from the brachio-radialis and extensor carpi radialis longus in the distal quarter. The ulnar nerve and the superior ulnar collateral (inferior profunda) artery are bound to its dorsal surface.
1. Dorsal or Extensor Group
Two muscles are included in this group, the triceps brachii and the anconeus. The triceps is a complex muscle in which proximally three heads, a long or scapular, a lateral humeral, and a medial humeral, may be distinguished. The long head arises from the infraglenoid tuberosity of the scapula, the lateral head from the humerus above and laterally to the groove for the radial nerve fmusculospiral groove), the medial head from the lower half and medial margin of the posterior surface of the humerus. Distally these heads fuse and are inserted by a common tendon into the olecranon of the ulna. The anconeus lies chiefly in the forearm, but physiologically and morphologically it belongs with the triceps, and hence is described in connection with the muscles of the arm. It is a triangular muscle, which arises from the lateral epicondyle and is inserted into the olecranon and adjacent part of the shaft of the ulna. Both muscles are supplied
The long head is also an adductor of the arm.
The triceps, variously modified, is found in the amphibia and all higher vertebrates. The anconeus is found in the prosimians and all higher forms. The triceps muscle is homologous with the quadriceps of the thigh. The long head is equivalent to the rectus femoris. The anconeus is not represented in the lower limb.
The triceps brachii (figs. 355, 356, 363). — The long head arises from the infraglenoid tuberosity of the scapula by a strong, broad tendon, some of the fibres of which are connected with the inferior portion of the capsule of the shoulder-joint. The tendon soon divides into two lamellse, which extend distally, one a short distance on the deep surface, the other much farther
Medial head of triceps
on the superficial surface of this head. The parallel fibre-bundles which arise from these lamellae form a thick muscle-baud which twists upon itself so that the ventral surface at the origin becomes dorso-medial at the insertion. At the insertion the long head becomes applied to an aponeurosis which extends upward from the main tendon of insertion of the triceps. The fibre-bundles extend for some distance on the medial side of this tendon and terminate about three-fourths of the way down the arm.
' The lateral head has a tendinous origin from the superior lateral portion of the posterior surface of the humerus along a line extending from the insertion of the teres minor as far as the groove for the radial (musoulo-spkal) nerve, and from the aponeurotic arch formed by the lateral intermuscular septum as it crosses this groove. The constituent fibre-bundles descend, the superior vertically, the inferior obliquely, to be inserted on the dorsal and ventral surfaces of the proximo-lateral margin of the common tendon of insertion of the triceps.
The medial head has a fleshy origin from the posterior surface of the humerus below the radial (musculo-spiral) groove and from the dorsal surfaces of the medial and lateral intermuscular septa. The greater part of the fibre-bundles arising from this extensive area are inserted into the deep surface of the common tendon, but some extend directly to the olecranon and the articular capsule of the elbow. The slip attached to the capsule is sometimes called the subanconeus muscle.
FLEXORS OF THE ARM 379
Insertion. — The tendon of insertion of the triceps forms a flat band covering the dorsal surface of the distal two-fifths of the muscle. It also extends proximally between the long and lateral heads and on the deep surface of the former. This tendon is inserted into the olecranon and laterally, by a prolongation over the anconeus, into the dorsal fascia of the forearm.
Neroe-supply. — From the radial (musculo-spiral) nerve. The branch to the long head arises in the arm-pit and enters that margin of the muscle which is prolonged down from the lateral edge of the tendon, but which, because of the torsion of the muscle, comes to he on the medial side. The nerve usually enters through several rami about the middle of the free portion of the long head. Somewhat more distally the radial nerve gives off a branch that enters, by two or three branches, the proximal portion of the medial head. A similar branch is given to the lateral head and other branches are given to the lateral and medial heads from that portion of the radial (musculo-spiral) nerve lying in the radial (musculo-spiral) groove." The nerve fibres arise from the sixth, seventh, and eighth cervical nerves.
Relations. — Near the shoulder the triceps is covered by the deltoid muscle. The long head passes between the teres major and teres minor muscles. The circumflex (dorsal) scapular vessels here pass medial, the circumflex humeral vessels and the axillary (circumflex) nerve lateral, to this head. It covers the radial groove of the humerus, in which run the radial (musculo-spiral) nerve and (superior) profunda brachii artery. Ventro-lateral to the muscle he the deltoid, brachialis, brachio-radialis, and extensor carpi radiaUs muscles; ventro-medial, the coraco-brachiahs, biceps, and brachialis muscles.
Action. — It extends the forearm. The leverage is of such a nature that force is sacrificed for speed of movement. The long head of the triceps also serves to extend and to adduct the arm and to hold the head of the humerus in the glenoid cavity.
Variations. — The scapular attachment may extend for a considerable distance down the axillary border of the scapula. Each of the heads may be more or less fused with neighbouring muscles. Frequently a fourth head is found. This may arise from the humerus, from the axillary margin of the scapula, from the capsule of the shoulder-joint, from the coracoid process, or from the tendon of the latissimus dorsi.
The latissimo-condyloideus (dorso-epitrochlearis).^This muscle is found in about 5 per cent, of bodies. When well developed, it extends from the tendon of the latissimus dorsi to the brachial fascia, the triceps muscle, the shaft of the humerus, the lateral epicondyle, the olecranon, or the fascia of the forearm. It is innervated by a branch of the radial (musculo-spiral) nerve. It is a muscle normally present in some one of the forms above mentioned or in some similar form, in a large number of the inferior mammals. In the human body it is normally represented by a fascial slip from the tendon of the latissimus to the long head of the triceps or the brachial fascia.
Structure and insertion. — The tendon of origin is prolonged on the deep surface and lateral border of the muscle. From this the fibre-bundles spread, the proximal transversely, the more distal obliquely, to be inserted into the radial side of the olecranon and an adjacent impression on the shaft of the ulna. Its superior fibre-bundles are usually continuous with those of the medial head of the triceps.
Nerve-supply. — By a long branch which arises in the radial (musculo-spiral) groove from the radial (musculo-spiral) nerve, passes through the medial head of the triceps, to which it gives branches, and enters the proximal border of the anconeus. The nerve fibres arise from the seventh and eighth cervical nerves.
The muscles of this group are the coraco-brachialis, the biceps, and the brachialis. The coraco-brachialis (fig. 365) is a band-like muscle which arises from the coracoid process and is inserted into the middle third of the shaft of the humerus. The biceps (fig. 364) arises by two heads: a short head, closely associated with the coraco-brachialis, fi"om the coracoid process; a long head, by an
extended tendon, from the supraglenoid tuberosity of the scapula. The fusiform belly whicli arises from the fusion of these two heads is inserted into the radius and into the fascia of the forearm. The brachialis (fig. 365) extends under cover of the biceps from the lower three-fifths of the shaft of the humerus to the coronoid process of the ulna. The muscles of this group are supplied by the musculocutaneous nerve. The brachialis also usually receives a branch from the radial nerve. The coraco-brachialis and short head of the biceps flex and adduct the arm at the shoulder; the biceps and brachialis flex the forearm at the elbow. The long head of the biceps abducts the arm at the shoulder.
The muscles of this group are found in most of the hmbed vertebrates. In many of the lower forms the coraco-brachialis, which appears farther down in the vertebrate series than the biceps, has a more extensive insertion than in man. It may extend to the ulna (lizards) and may be subdivided into various muscles which correspond with the adductors of the thigh. The biceps, the place of which is taken in the lower vertebrates by a coraco-radial muscle, in most of the mammals presents two heads, the more lateral of which is attached by a tendon to the scapula above the shoulder-joint. This long tendon of the biceps lies primitively outside the capsule of the shoulder-joint, but in some of the higher mammals has come to lie within the capsule. In the biceps four elements mayberecogni.sed; — a coraco-radial, coraco-ulnar, glenoradial, and gleno-ulnar. (Krause.) The development of these elements varies in different mammals
Insertion. — (1) By means of a strong tendon into the medial surface of the humerus immediately proximal to the middle of the shaft, and (2) often above this also into an aponeurotic band which e.xtends from the tendon along the medial margin of the humerus, arches over the tendons of the latissimus dorsi and teres major, and is attached to the lesser tubercle of the humerus. When the attachment to the tubercle does not take place, the band becomes closely applied to the deep surface of the muscle.
mentioned and to both surfaces of the flat tendon of insertion. This extends high into the muscle. The belly of the muscle usually shows some separation into a superficial and a deep portion, between which runs the musculo-cutaneous nerve. When this separation is well marked, the tendon of origin of the superior fasciculus may be distinct from that of the inferior fasciculus and the short head of the biceps, and the tendon of insertion may give a separate lamina to each fasciculus.
Nerve-supply. — A branch of the musculo-cutaneous nerve, or of the brachial plexus near the origin of this nerve, enters the upper third of the medial border of the muscle, and passes across the constituent fibre-bundles about midway between their attachments. The nerve fibres arise from the sixth and seventh cervical nerves.
usually runs through it.
Variations. — The humeral insertion of the muscle varies considerably. According to Wood, the coraco-braohialis consists primitively of three parts, which arise from the coraooid process and are inserted respectively into the upper, the middle, and the distal part of the humerus along the medial side. The superior division is most deeply, the inferior the most superficially, placed. In man the muscle is composed of parts of the middle and inferior divisions. The inferior division may be completely developed as far as the medial epicondyle. The superior division of the muscle is occasionally found. Slips from the coraco-brachialis to the brachiahs have been seen. Complete absence of the muscle has been recorded.
The biceps brachii (figs. 364, 370). — The short head arises by a flat tendon closely associated with that of the coraco-brachialis from the coracoid process. From the dorso-medial surface of this tendon the fibre-bundles descend nearly vertically, though increasing in number, toward their attachment to the tendon of insertion. The fibre-bundles which arise highest on the tendon of origin are inserted highest on the tendon of insertion, while those which have the lowest origin have the lowest insertion.
The long head arises from the supraglenoid tuberosity and from the glenoid ligament by a long tendon (9 cm.) bifurcated at its origin. The tendon at first passes over the head of the^humerus within the capsule of the joint, and then passes into the intertubercular (bicipital) groove, which is covered by the capsule of the joint and an expansion from the tendon of the pectoralis major. To this point the tendon is surrounded by the synovial membrane of the joint. After emerging from this the tendon slowly expands and from its dorsal concave surface arise fibre-bundles which, increasing in number, extend, somewhat obliquely, toward the tendon of insertion. As in case of the short head, here also the fibre-bundles which arise highest on the tendon of origin have the highest insertion.
Insertion. — The tendon of insertion begins usually in the distal quarter of the arm as a vertical septum between the two heads of the muscle. More distally this broadens out on each side into a flattened aponeurosis. The fibre-bundles are inserted into the sides of the septum and on each surface of the aponeurosis — those of the long head chiefly on the deep surface, those of the short head chiefly on the superficial surface. The aponeurosis is continued into a strong, flattened tendon which descends between the brachio-radialis and pronator teres muscles to be inserted on the dorsal half of the bicipital tuberosity of the radius. From the medial border of the tendon an aponeurotic expansion, the lacertus fibrosus (semilunar fascia), is continued into the fascia of the ulnar side of the forearm.
Nerve-supply. — By a branch from the musculo-cutaneous nerve for each head. These branches may be bound in a common trunk for some distance. They enter the deep surface of the muscle in the proximal part of the middle third of each belly often by several rami. Usually there is a distinct intramuscular fissure for the reception of the branches to each head and the blood-vessels which accompany them. The nerve fibres come from the fifth and sixth cervical nerves.
Action. — It is a chief flexor of the arm at the elbow and is also a supinator of the forearm. This last action is most marked when the forearm is flexed and pronated. Both heads are flexors and medial rotators of the arm at the shoulder. The long head is an abductor and so also is the short head when the arm is greatly abducted, otherwise the short head is an adductor.
Relations. — The tendons of origin are concealed by the pectoralis major and deltoid muscles. Beyond this the muscle is covered by the fascia brachii. In the lower part of the ai-m it lies upon the brachialis muscle. Upon the medial margin lie the coraco-brachialis muscle, the brachial vessels, and the median nerve.
Variations. — Variations are frequent. The whole muscle or either head may be missing, but such cases are rare. The long head may extend only to the bicipital groove. Frequently the muscle is partially divided into the four primitive portions mentioned above. The two heads may be separate from origin to insertion. There may be an accessory head (1 in 10 subjects — Le Double) which arises from the coracoid process, the capsule of the joint, the tendon of the pectoralis major, or the shaft of the humerus near the insertion of the coraco-brachialis. In most instances the origin takes place above the origin of the brachialis from the humerus. Sometimes several accessory heads are seen. Marked vai-iation of insertion is less frequent, but occasionally a supernumerary slip may go to the medial intermuscular septum or the medial epicondyle. The fusion of the biceps with neighbouring muscles (pectoralis major and minor, coraco-brachialis, brachialis, palmaris longus, pronator teres, brachio-radialis) by means of tendinous or muscular slips has been frequently reported.
The brachialis (fig. 365). — Origin. — (1) From the distal three-fifths of the front of the humerus, (2) from the medial intermuscular septum, and (3) from the lateral intermuscular septum proximal to the heads of the brachio-radialis and extensor carpi radiaUs longus. Proximally it sends up a pointed process on the lateral side of the insertion of the deltoid and another between the insertions of the deltoid and the coraco-braohiahs. Distally the area of origin stops a little above the capitulum and the trochlea.
Structure and Insertion. — The fibre-bundles arise directly from this area of origin, except near the insertion of the deltoid and on the medial margin, where tendinous bands are developed. The fibre-bundles descend, the middle vertically, the medial obliquely lateralward, the lateral still more obliquely medialward. The tendon of insertion appears on the dorsal side of the lateral edge of the muscle in its lower fourth. Continuous with this stronger lateral portion of the tendon more distally a thinner band appears upon the ventral surface of the muscle above the joint. The tendon becomes thick as it passes distally, is closely united to the capsule of the elbow-joint, and is attached to the ulnar tuberosity. In addition to the main tendon, some of the deeper fibre-bundles of the muscle and some of those coming from the lateral intermuscular septum are attached by short tendinous bands to the coronoid process.
MUSCLES OF FOREARM AND HAND 383
Neri/e-supply. — From the museulo-cutaneous nerve by a branch which enters the ventral surface of the muscle near the junction of the upper and middle thirds of the medial border. In addition the radial (musculo-spiral) nerve usually sends a small branch into the distal lateral portion of the muscle. A branch from the median nerve frequently supplies the medial side of the muscle near the elbow-joint (Frohse).
Relations. — It lies behind the biceps, on each side of which it projects. The distal lateral portion of the muscle is grooved by the brachio-radialis, which here is closely apphed to it. The radial (musculo-spiral) nerve runs between these two muscles. On the medial side run the brachial vessels and median nerve.
Variations. — It may be divided into two distinct heads continuous with the projections on each side of the deltoid tuJjerosity. A great number of supernumerary slips have been recorded. These may be attached to the radius, ulna, fascia of the forearm, capsule of the joint, brachioradialis, and extensor carpi radialis muscles. It may be partially fused with neighbouring muscles. It has also been reported absent.
The muscles of the forearm arise in part from the humerus, in part from the radius and ulna. Their bellies lie chiefly in the proximal half of the forearm. They are divisible into two groups: — a radio-dorsal, composed of extensors of the hand and fingers and supinators of the forearm; and an ulno-volar, composed of flexors of the hand and fingers and pronators of the forearm. The brachioradialis, which belongs morphologically with the former group, is physiologically a flexor of the forearm.
The two groups are separated on the medial side of the back of the forearm by the dorsal margin of the ulna (figs. 366, 369). Ventrally they are separated by the insertions of the biceps and brachialis and by an intermuscular septum (figs. 366, 370).
In the hand, in addition to the tendons of the muscles of the forearm mentioned above (fig. 376), there are several sets of intrinsic muscles. About the metacarpal of the thumb (figs. 375, 376, 377) is grouped a set of muscles which arise from the carpus and metacarpus and are inserted into the metacarpal and first phalanx of the thumb. A similar set of muscles is grouped about the metacarpal of the little finger (figs. 375, 376). These sets of muscles give rise respectively to the thenar and hypothenar eminences. Between the metacarpals lies a series of dorsal and palmar interosseous muscles (figs. 377, 378, 379) which are inserted into the first row of phalanges and into the extensor tendons. From the tendons of the deep flexor of the fingers a series of lumbrical muscles passes to the radial side of the extensor tendons (figs. 373, 375). These various muscles abduct, adduct, flex, and extend the digits. In addition to these deeper skeletal muscles of the hand there is a subcutaneous muscle over the hypothenar eminence (fig. 375). Of the muscles of the hand, all are supplied by the ulnar nerve except most of those of the thumb and the two more radial lumbricals, which are supplied by the median nerve.
An arrangement of the muscles of the forearm in which the dorsal extensor-supinator musculture extends proximally on the radial side of the arm to the distal extremity of the humerus, and the volar flexor-pronator musculature similarly on the ulnar side, is characteristic of all limbed vertebrates and is associated with the pronate position of the forehmb characteristic of quadrupeds. In ampliibia and reptiles the musculature terminates distaUy on the carpus and in the aponeuroses of the hand. In the higher forms special tendons are differentiated for those muscles of the forearm which act on the fingers. On the back of the hand in many vertebrates short extensor muscles are found running from the carpus to the phalanges. On the volar surface a complex musculature is found in all forms which have freely movable fingers. In animals which walk on the ends of the fingers, especially in the hoofed animals, the intrinsic musculature of the hand is greatly reduced. The phylogenetic development of the muscles of
the forearm and hand is too complex a subject to be briefly summarised. The phylogeny of the forearm flexors and the palmar musculature has been studied by McMurrich. In his papers a summary of the hterature on the subject may be found.
The tela subcutanea contains a moderate amount of fat in the upper part of the forearm. This grows less in amount as the wrist is approached. On the back of the hand it contains little fat. In the palm and on the volar surface of the fingers a moderate amount of fat is embedded between dense vertical bundles of fibres which unite the skin to the fascia. Except on the volar surface of the hand and on the backs of the terminal phalanges, the tela is but loosely united to the underlying fascia.
The bursa subcutanea olecrani lies over the dorsal surface of the olecranon. Subcutaneous bursiE are also frequently found over the knuckles (b. subcutanese metacarpophalangeae dorsales) and the proximal joints of the fingers (b. subcutanese digitorum dorsales).
The antibrachial fascia encloses the muscles of the forearm in a cylindrical sheath, composed in the main of circular fibre-bundles, but strengthened by longitudinal and obhque bundles extending in from the epicondyles of the humerus, the olecranon, the lacertus fibrosus of the biceps, and the tendon of the triceps. The fascia of the forearm is attached to the dorsal surface of the olecranon and to the subcutaneous margin of the ulna. Above, it is continued into the fascia of the arm; below, into the fascia of the hand. From the antibrachial fascia in the upper half of the foreai-m a fibrous septum extends between the radio-dorsal and the ulno-volar muscle group to the radius. In the radial septum below the elbow a branch of communication extends between the superficial and deep veins of the arm. That part of the fascia overlying the radio-dorsal group of muscles is much denser than that covering the volar group, except where the latter is strengthened by the lacertus fibrosus. In addition to the main radial septum other septa descend between the underlying muscles from the antibrachial fascia. These septa are best marked near the attachment of the muscles to the humerus. Here the fascia is firmly fused to the muscles.
Dorsally the antibrachial fascia is strengthened at the wrist by transverse fibres which extend from the radius to the styloid process of the ulna, the triquetrum (cuneiform), and pisiform, and give rise to the dorsal ligament of the carpus (posterior annular ligament). From this ligament septa descend to the radius and ulna and convert the grooves in these bones into osteo-fibrous canals which lodge the tendons of the various muscles extending to the wrist and hand.
On the back of the hand there is spread a fascia composed of two thin fascial sheets between which the extensor tendons are contained. Between the tendons these sheets are more or less fused. On the backs of the fingers the fascia blends with the extensor tendons and.the associated aponeurotic expansions from the interosseous and lumbrical muscles. Between the fingers it is continued into the transverse fasciculi of the palmar aponeurosis. At the sides of the hand the fascia is continued into the thenar and hypothenar fasciae. Each dorsal interosseous muscle is covered by a special fascial membrane which is separated by loose tissue from the fascia investing the e.xtensor tendons.
H. Transverse section through the first phalanx of the middle finger, diagrammatic, with the cavity of the synovial sheath of the flexor tendons distended. The regions through which these sections pass are indicated in the diagram, c and d in the diagram show the regions through which pass sections C and D, fig. 362 (p. 375).
1. Aponeurosis palmaris. 2. Arteria radialis. 3. A. ulnaris. 4. Bursa bicipito-radiahs. 5 Discus articularis. 6. Ligamentum carpale dorsale. 7. L. carpi transversum. 8. L. carpi volare. 9. Fascia antibrachii. 10. Musculus abductor pollicis brevis. 11. M. abductor pollicis longus — a, tendon. 12. M. abductor digiti quinti. 13. M. adductor polhcis. 14. M. anconeus. 15. M. biceps, tendon. 16. M. brachialis, tendon. 17. M. braohio-radialis — a, tendon. 18. M. extensor carpi radiahs brevis — a, tendon. 19. M. extensor carpi radiahs longus — a, tendon. 20. M. extensor carpi ulnaris. 21. M. extensor digitorum communis — a, tendon for second finger; b, tendon for the third finger; c, tendon for fourth finger; d, tendon for fifth finger; e, digital aponeurosis. 22. M. extensor digiti quinti proprius. 23. M. extensor indicis proprius. 24. M. extensor polhcis brevis — a, tendon. 25. M. extensor poUicis longus — a, tendon. 26. M. flexor carpi radialis — a, tendon. 27. M. flexor carpi ulnaris — a, tendon. 28. M. flexor digitorum profundus — a, tendon for second finger; b, tendon for third finger; c, tendon for fourth finger; d, tendon for fifth finger. 29. M. flexor digitorum sublimis — a, tendon for second finger; b, tendon for third finger; c, tendon for fourth finger; d. tendon for fifth finger. 30. M. flexor digiti quinti brevis. 31. M. flexor pollicis brevis. 32. M. flexor pollicis longus — a, tendon. 33. M. interossei dorsales. 34. M. intero.ssei volares. 35. M. lumbricales. 36. M. opponens polhcis. 37. M. opponens digiti quinti. 38. M. palmaris brevis. 39. M. palmaris longus — a, tendon. 40. M. pronator quadratus. 41. M. pronator teres. 42. M. supinator. 43. N. cutaneus antibrachii lateralis. 44. N. medianus. 45. N. radialis — a, deep radial nerve; b, superficial radial nerve. 46. N. ulnaris. 47. Os capitatum (magnum). 48. Os hamatum (unciform). 49. Os lunatum (semilunar). 50. Os metacarpal, I. 51. Os metacarpale, II. 52. Os metacarpale. III. 53. Os metacarpale, IV. 54. Os metacarpale, V. 55. Os multangulum majus (trapezium). 56. Os naviculare. 57. Ossa sesamoidea of fifth digit. 58. Radius. 59. Ulna. 60. Vagina fibrosa (tendonsheath) of the long digital flexors. 61. Vagina fibrosa (tendon-sheath) of the flexor pollicis longus. 62. Vagina fibrosa (tendon-sheath in digit). 63. Vena cephalica.
On the volar side of the forearm for some distance above the wrist the tendons of the flexor carpi radialis, tlie palmaris longus, and the flexor carpi ulnaris run between two layers of the fascia. The fascia is much strengthened at the wrist by transverse fibres which give rise to the volar ligament of the carpus. Beneath it hes the transverse ligament of the carpus (anterior annular hgament). This dense band is broader than the volar ligament but like it extends from the pisiform bone and the hamulus of the hamatura (unciform) to the tuberosity of the navicular and the tuberosity of the greater multangular (trapezium). It serves to complete an osteo-fibrous canal through which pa.ss the flexor tendons of the fingers. Between the two ligaments which are partially fused with one another run the ulnar artery and nerve.
a lateral, and a medial.
The central portion, the palmar aponeurosis, is composed chiefly of bundles of fibrous tissue which radiate superficially toward the fingers from the tendon of the palmaris longus or from a corresponding region of the forearm fascia when this muscle is absent. Between these bundles are others which arise from the transverse ligament. The deep surface of the fascia is composed of a thin incomplete layer of transverse fibres which continue the transverse fibres of the forearm fascia. Near the capitula of the metacarpals this layer becomes much stronger and constitutes a ligamentous band (superficial transverse ligament of Poirier). Near the bases of the digits bundles of transverse fibres (fasciculi transversi) lie in the webs of the fingers and constitute an incomplete transverse ligament separated by a distinct interval from the superficial transverse ligament.
From the palmar aponeurosis processes are sent in toward the deeper structures. Of these, the most important are those continued into a fibrous sheath which surrounds the space containing the long flexor tendons and the lumbrical muscles. This dense fibrous sheath is united by fibrous processes to the third, fourth, and fifth metacarpals. As the flexor tendons diverge and the ends of the metacarpals are approached, numerous processes descend from the palmar aponeurosis to the transverse capitular ligament. These hold the tendons in place. On the volar surface of the fingers the fascia serves to complete osteo-fibrous canals for the long flexor tendons. The ventral surface of the first and second phalanges of each finger is slightly grooved. The fascia is firmly united on each side to the margin of the groove, and over the groove forms a semicyhndrical, strong, fibrous sheath, the vaginal ligament of the finger. This sheath is strengthened by transverse bands over the bases of the first and second phalanges (annular ligaments) and by cruciate bands over the shafts of the phalanges (cruciate ligaments). Over the interphalangeal joints the sheath is thin, but is strengthened by crucial bands which permit of freedom of motion.
The thenar fascia is a thin membrane covering the short muscles of the thumb. It is continued above into the fascia of the forearm, medially is fused with the tendon of the palmaris longus and the palmar aponeurosis, and extends as a septum to be attached to the third metacarpal. Laterally it is attached to the first metacarpal and is continued into the dorsal fascia of the hand. It is fused with an aponeurosis from the tendon of the abductor poUicis longus. Distally it is continued into the vaginal ligament of the long flexor of the thumb. Superficially it is closely adherent to the skin.
The hypothenar fascia invests the palmar muscles of the little finger. It is continued from the ulnar margin of the fifth metacarpal over the muscles of the little finger to the palmar aponeurosis, and, by means of a septum, to the radial side of the fifth metacarpal. Proximally, it is attached to the hamatum (unciforn?^ and extends into the fascia of the forearm, distally, it extends into the vaginal ligament of the tendon of the fifth digit.
The muscles of this laj^er, closely associated at their origins, extend from the radial .side of the distal end of the humerus to the distal extremity of the radius, the carpus, and the fingers. They are divisible into a radial, an intermediate, and an ulnar set.
Radial set. — To this belong three muscles, the brachio-radialis, extensor carpi radialis longus and brevis. The brachio-radialis (fig. 370), a forearm flexor, is a superficial fusiform muscle which arises from the lateral epicondylar ridge of the humerus and is inserted into the base of the styloid process of the radius. The extensor carpi radialis longus (fig. 371) is a narrow, fusiform muscle which extends
along the radial margin of the forearm, partly under cover of the brachio-radialis. It arises from the lateral epicondylar ridge of the humerus, and is inserted into the second metacarpal bone. The extensor carpi radialis brevis (fig. 367) is a band-like muscle more dorsally placed than the last at the radial side of the arm. It arises from the lateral epicondyle and is inserted into the bases of the second and third metacarpals. These muscles are supplied by branches of the radial nerve which arise proximal to the passage of the deep radial (posterior interosseous) through the supinator muscle. Distally this set of muscles is separated from the intermediate set by the long abductor and the extensors of the thumb, which pass from an origin under the latter set over the tendons of the radial extensors to the thumb.
The intermediate set. — This consists of the thick, flattened extensor digitorum communis and the slender extensor digiti quinti proprius (fig. 367). They arise from the lateral epicondyle, and are inserted into the backs of the fingers.
The ulnar set consists of one muscle, the fusiform extensor carpi ulnaris, which arises from the lateral epicondyle of the humerus and is inserted into the back of the base of the fifth metacarpal.
In the leg the lateral set of the superficial layer is represented by the tibialis anterior. The intermediate set is represented by the long extensors of the toes. The single muscle which constitutes the medial set is represented by the peroneal muscles.
Structure. — The constituent fibre-bundles arise directly from the septum and by short tendinous bands from the epicondylar ridge, extend downward and ventrally, and terminate in a penniform manner on a tendon which extends high on the deep surface of the muscle. This tendon becomes free about the middle of the forearm as a broad, flat band. This becomes narrow as the tendon winds about the radius from the volar to the lateral surface. Before its insertion it expands laterally and is connected with neighbouring ligaments. The free surface of the muscle faces laterally at its origin, but, owing to the torsion, ventrally in the forearm. The tendon, however, is turned again so that at the insertion it faces laterally once more.
Action. — To flex the forearm. This action is strongest when the forearm is pronated. It acts as a supinator only when the arm is extended and pronated. It then serves to put the arm in a state of semi-pronation. When the forearm is flexed, it acts as a pronator.
Relations. — The muscle is superficially placed on the ventro-lateral surface of the forearm. Its tendon of insertion, however, is covered by the long abductor and the short extensor of the thumb. Near its origin (fig. 367) it lies lateral to the brachialis. In the intervening tissue run the radial nerve and the terminal branch of the profunda brachii artery. Dorsally and laterally lieslthe medial head of the triceps. More distally the muscle overlies the extensor carpi radialis longus. It crosses the supinator, pronator teres, and flexor pollicis longus muscles. Beneath its medial edge lie the radial vessels and nerve.
Variations. — The humeral origin may extend half-way up the shaft. The radial insertion may be as high as the middle of the shaft or descend to the lesser multangular, navicular, or third metacarpal. In about 7 per cent, of bodies (Le Double) the tendon of insertion divides into two or three slips which are inserted on the styloid process of the radius. Occasionally the radial nerve passes between these slips. An accessory slip may pass to the fascia of the forearm. The muscle may be doubled throughout its length and it may be missing. It may be connected by accessory slips with neighbouring muscles, the deltoid, brachialis, long abductor of the thumb, or long radial carpal extensor. The slip most frequently found goes to the brachiahs.
The extensor carpi radialis longus (figs. 367, 368, 371.) — Origin. — From the lower third of the lateral epicondylar ridge, the lateral intermuscular septum, and from the front of the tendons of the extensor carpi radialis brevis and the extensor communis digitorum which arise from the lateral epicondyle.
Structure and insertion. — The fibre-bundles are inserted in a penniform manner on both surfaces of a tendon which first appears on the lateral border of the deep surface of the muscle, becomes free above the middle of the forearm, and descends, closely applied to the tendon of the short radial carpal extensor, to the second compartment beneath the dorsal carpal ligament, through which it passes to its insertion into the base of the second metacarpal near the radial border. The outer surface of the muscle faces at first laterally, then ventrally.
Nerve-supply. — By one or two branches which arise from the radial (musculo-spiral) nerve as it passes between the brachialis and brachio-radialis. The nerve enters the deep surface of the muscle in the proximal third. The nerve fibres arise from the (fifth), sixth and seventh cervical nerves.
when it is flexed.
Relations. — It is covered by the brachio-radialis near the elbow. Below it becomes superficial except where crossed by the tendons of the muscles of the thumb. (For the relations to the short radial carpal extensor see below.)
Variaiions. — The humeral attachment may be more extensive than that indicated above. The tendon of insertion may send a band to the third or to the fourth metacai'pal or to the multangulum majus (trapezium). The muscle may be fused, partly or completely, with the short radial extensor. It may send a slip to the abductor pollicis longus or to some of the interossei.
The extensor carpi radialis brevis (figs. 367, 368). — Origin. — From a band which descends on its deep surface from the common extensor tendon attached to the lateral epicondyle, from the intermuscular septa surrounding its head, and from the radial collateral ligament of the elbow-joint.
Structure and insertion. — The fibre-bundles converge obliquely toward a tendon which appears high up on the dorso-lateral surface of the muscle. Toward the lower third of the forearm this tendon becomes a free, strong band closely apphed to the under surface of the tendon of the long radial extensor, and with this passes through the second compartinent beneath the dorsal ligament of the carpus, diverging as it does so toward its insertion into the back of the bases of the second and third metacarpal bones.
to third phalanx
Nerve-supply. — A branch is supplied to the muscle from the deep radial (posterior interosseous) nerve before this enters the supinator (brevis). The branch enters the middle third of the medial margin of the muscle by several rami. The nerve fibres arise from the (fifth), sixth and seventh cervical nerves.
Relations. — In its proximal portion the muscle is placed with a medial surface toward the common extensor, a deep toward the supinator (brevis) and pronator teres, and a dorsolateral toward the long radial extensor. More distally the muscle and its tendon become flattened about the radius and partly covered by the long radial extensor and its tendon.
EXTENSOR CARPI ULNARIS 391
In the distal quarter of the forearm the tendons of these two muscles are crossed by the long abductor and the short extensor of the thumb. Beneath the dorsal carpal ligament the tendon of the short radial extensor is crossed by the tendon of the long extensor of the thumb.
Variations. — The tendon often sends no slip to the second metacarpal. Fusion of the two radial extensors is frequent. The fused muscle may have from one to four tendons. The extensor carpi radialis intermedius of Wood is a muscle which arises, rarely directly from the humerus, but not infrequently as a slip from one or both radial extensors. It is inserted into the second or third metacarpal bone or into both. The extensor carpi radialis accessorius is a muscle which has an origin like the extensor intermedius, but which terminates on the base of the metacarpal or first phalanx of the thumb, the short abductor of the thumb, or some neighbouring structure.
The extensor digitorum communis (figs. 367, 368). — Origin. — From a tendon attached to the lateral epicondyle, and from intermuscular septa which lie between the head of the muscle and the short radial extensor, the extensor of the Uttle finger, and the supinator muscle.
Structure. — The fibre-bundles arise from the interior of the pyramidal case formed by the tendon, the fascia, and intermuscular septa, and pass distally to converge on four tendons which begin in the middle of the forearm, become free a little above the wrist, pass under the dorsal carpal ligament in a groove common to them and the tendon of the extensor indicis proprius, and diverge to the backs of the fingers. Opposite the metacarpo-phalangeal joint each tendon gives rise on its under surface to a band which becomes attached to the base of the first phalanx of its respective digit. The tendon is also closely bound to the joint by fibrous bands connected with the palmar fascia. On the dorsum of the first phalanx the tendon expands and is bound to an aponeurotic extension from the interosseous and lumbrical muscles. The tendon divides into three bands. The middle band passes to the base of the second phalanx, the lateral bands pass laterally around the joint to be inserted into the back of the base of the third phalanx. The lateral bands are bound to the second joint by a thin layer of transverse and oblique fibres.
An obliquely transverse band usually passes from the tendon of the index to that of the middle finger above the heads of the metacarpals. The tendon to the index finger is united to the tendon of the extensor indicis proprius opposite the metacarpo-phalangeal articulation. The tendon to the ring finger usually sends a slip to join the tendon of the middle finger. The fourth tendon lies near that of the ring finger and divides into two shps, one of which joins the tendon of the ring finger and one goes to the little finger to join the tendon of the extensor digiti quinti proprius.
Nerve-supply. — From a branch which arises from the deep radial (posterior interosseous) nerve as it emerges from the supinator (brevis) muscle. From this several twigs enter the deep surface of the middle third of the belly. On the other hand, there may be several separate branches to the muscle. The nerve fibres arise from the sixth, seventh, and eighth cervical nerves.
Action. — The muscle extends the two terminal phalanges on the basal, the basal on the metacarpus, and the hand at the wrist. The extensor action is strongest on the first phalanx. The cross-bands between the tendons hinder ^Jie independent extension of the middle and ring fingers, while the special extensors of the index and little fingers makes the movements of these fingers freer. When the hand is abducted toward the radial side, the extensor muscles tend to draw the fingers ulnarward. When the hand is abducted toward the ulnar side, the muscles tend to draw the fingers toward the thumb. When the hand is in the mid-position the ring finger and little finger are abducted and the index-finger is adducted. (Frohse.)
Relations. — It is superficially placed. Under it lie the deep muscles of the back of the forearm, the interosseous vessels, and the deep radial (posterior interosseous) nerve. It lies between the short radial carpal extensor and the extensor of the little finger.
Variations. — There is considerable variation in the extent of isolation of the parts going to the various fingers. That to the index-finger is the one most frequently isolated. At times the tendon to the index or httle finger may be wanting. More frequently one or more of the tendons subdivides to be attached to two or more fingers or to the thumb. The connections between the tendons on the back of the hand vary greatly.
The extensor digiti quinti proprius (extensor minimi digiti) (figs. 367, 368). — Origin. — Chiefly from the septum between it and the common extensor, but also in part from the septum between it and the extensor ulnaris and from the overlying fascia.
Structure and insertion. — The fibre-bundles descend in a narrow band which begins near the neck of the radius. They are inserted into the side of a tendon which begins high on the ulnar margin of the muscle. The most distal fibre-bundles extend nearly to the wrist-joint. The tendon passes through the fifth compartment beneath the dorsal carpal ligament, and extends on the back of the fifth metacarpal to the base of the first phalanx of the little finger, where it is joined by a shp from the fourth tendon of the common extensor. The insertion of the tendon is Uke that of the tendons of the common extensor.
Nerve-supply. — By a branch or branches from the deep radial (posterior interosseous), nerve. The nerve filaments enter the middle third of the fleshy portion of the muscle on its deep surface. The innervation of this muscle is intimately related to that of the preceding.
muscles of the back of the forearm.
Variations. — Absence is not very frequent; blending with the common extensor is frequent. Its tendon often divides into two or more slips. The belly may also be doubled. It may have a supplementary origin from the ulna. A tendon shp to the ring-finger is frequently found.
the dorsal border of the ulna.
Structure and insertion. — The fibre-bundles descend in an osteo-fascial compartment bounded by the dorsal surface of the ulna, the fascia of the forearm, the dense fascia overlying the ulnar origin of the muscles of the thumb, and the origin of the extensor indicis. The tendon commences high in the muscle and appears on the radial border of the middle third of the back of its belly. The fibre-bundles are inserted in a penniform manner on the ulnar border and deep surface of the tendon as far as the wrist. Here the tendon enters the sixth osteo-fibrous canal beneath the dorsal carpal Ugament in a special groove on the outer side of the styloid process of the ulna. It is inserted into the base of the fifth metacarpal.
Nerve-supply. — By a branch which arises from the deep radial (posterior interosseous) nerve as this emerges from the supinator (brevis) muscle. Several filaments enter the deep surface of the muscle in the middle third. The nerve fibres arise from the sixth, seventh and eighth cervical nerves.
Variations. — It may receive a slip from the triceps or be fused with the anconeus or with the extensor of the little finger. More frequently it is doubled, partially or completely. An accessory tendon may go to the first phalanx of the little finger, to the head of the fifth metacarpal, to the fourth metacarpal, to the extensor tendon of the little finger, or to the fascia over the opponens digiti quinti. The muscle may be reduced to a fibrous band. The ulnaris digiti quinti is a rare muscle arising from the dorsal surface of the ulna and inserted into the base of the first phalanx of the httle finger. It may be represented by a fasciculus or an extra tendon from the ulnar extensor.
The muscles of this group extend from the ulna to the radius, thumb, and indexfinger. They are the supinator, abductor pollicis longus, extensor pollicis longus and brevis, and extensor indicis proprius. The supinator is a rhomboid muscle which arises from the lateral epicondyle of the humerus and the supinator crest of the ulna winds laterally around the radius and is inserted into its volar surface. The abductor pollicis longus is a fusiform muscle which arises from the middle third of the ulna, the interosseous membrane, and the radius, and is inserted into the base of the first metacarpal. The extensor pollicis brevis arises from the radius distal to the preceding muscle, and is inserted into the base of the first phalanx of the thumb. The extensor pollicis longus is a narrow muscle which arises from the middle third of the dorsal surface of the ulna and is inserted into the base of the second phalanx of the thumb. The extensor indicis proprius is a narrow, fusiform muscle arising from the shaft of the ulna and inserted into the dorsal aponeurosis of the index-finger. These muscles are supplied from branches of the deep radial (posterior interosseous) nerve while this is passing through or after its exit from the supinator.
The extensor pollicis longus is represented by the extensor hallucis longus of the leg. The abductor pollicis longus and extensor pol'icis brevis are represented by the abnormal abductor hallucis longus and extensor primi internodii hallucis muscles, the rudiments of which are perhaps normally present in the tibialis anterior. The supinator and the extensor indicis muscles are not represented in the leg. On the other hand, the extensor digitorum brevis, norma! in the foot, is only occasionally found on the back of the hand.
The supinator (brevis) (figs. 366, 369, 372). — Origin. — From (1) the inferior dorsal portion of the lateral epicondyle by a tendinous band which is adherent to the deep surface of the tendons of origin of the radial and common extensors and to the radial collateral ligament of the joint; and (2) the ulna by a superficial aponeurosis and by fibre-bundles attached directly to the depression below the radial notch and to the supinator crest.
ment of the pronator teres.
Structure. — From their origin the fibre-bundles descend spirally in a muscular sheet which enwraps the radius (fig. 366). The attachment extends to the oblique Une. The muscle is divided into a superficial and a deep plane by a septum in which the deep radial (posterior interosseous) nerve runs. The radial attachments of these two portions are separated by an osseous area into which no fibre-bundles are inserted. The fibre-bundles of the superficial layer have a much more vertical course and are longer than those of the deep layer.
Nerve-supply. — By branches which arise from the deep radial (posterior interosseous) nerve before it passes between the two layers of the supinator muscle. The nerve fibres arise from the fifth, sixth, and seventh cervical nerves.
ABDUCTOR POLLICIS LONGUS
' Variations. — The extent of separation of the muscles into two portions varies. Accessory fasciculi of origin are not uncommon. These may spring from the annular ligament, tensor ligamenti annularis anterior (5 per cent, or more of bodies — Le Double), the lateral epicondyle, the tendon of the bi ceps, the tuberosity of the radius, etc. A sesamoid bone may lie in the tendon of origin. The tensor ligamenti annularis posterior is a sUp generally present and often independent of the supinator. It runs from the ulna behind the radial notch to the annular ligament of the radio-ulnar joint.
and the adjacent interosseous membrane, (2) the dorsal surface of the radius distal and medial to the attachment of the supinator, and (3) at times, from the septa lying between it and the supinator, extensor carpi ulnaris, and extensor polUcis longus.
Structure and insertion. — The fibre-bundles from this extensive area of origin converge in a bipenniform manner upon a tendon which appears as an aponeurosis on the deep surface of the muscle about the middle of the forearm. The tendon as it descends becomes rounded. The insertion of fibre-bundles continues nearly to the wrist. Here, together with the tendon of the short extensor, it enters the first osteo-fibrous canal beneath the dorsal carpal ligament upon the lateral surface of the distal extremity of the radius. Upon leaving this canal the tendon extends to be inserted on the radial side of the base of the first metacarpal bone.
contraction it flexes and abducts the hand at the wrist.
Relations. — Near its origin the muscle is covered by the superficial extensors of the forearm. More distally, accompanied by the short extensor, it passes radially, becomes superficial, and crosses the tendons of the two radial carpal extensors.
Variations. — The muscle or its tendon may be doubled. An accessory tendon may be applied to the multangulum majus (trapezium), the transverse ligament of the carpus, the superficial muscles of the thenar eminence, or the first metacarpal. Of these, the attachment to the short abductor and short flexor is the most frequent (7 out of 36 bodies — Wood). There may be three or more tendons. The muscle may be fused with the short extensor.
The extensor poUicis brevis (fig. 369). — Origin. — From the distal part of the middle third of the medial portion of the dorsal surface of the radius and from the neighbouring portion of the interosseous membrane. Rarely its origin extends to the ulna.
Structure and insertion. — The fibre-bundles converge on a tendon which appears on the radial border. The fibres are inserted as far as the dorsal carpal (posterior annular) ligament. The tendon hes parallel to the ulnar side of that of the abductor poUicis longus, and, in close connection with it, passes through the first compartment beneath the dorsal carpal ligament, and crosses the metacarpo-phalangeal joint on the radial side of the long extensor tendon. It is inserted on the base of the first phalanx of the thumb or into the capsule of the metacarpophalangeal joint.
Nerve-supply. — From a branch derived from the deep radial (posterior interosseous) nerve. This branch is usually given off in common with or near the nerve to the abductor pollicis longus, and many traverse that muscle to reach the extensor pollicis brevis, which it enters in the proximal third of its radial border. The nerve fibres come from the sixth, seventh (and eighth) cervical nerves.
metacarpal. It likewise acts as a weak supinator of the forearm.
Relations. — It hes between the abductor pollicis longus and the extensor pollicis longus, by which its origin is partly overlapped. In company with the former muscle it passes medially from beneath the common extensor of the fingers and over the tendons of the radial carpal extensors to reach its osteo-fibrous canal under the dorsal carpal hgament.
Variations. — The head of the mu3cle may be fused with the long abductor. Its tendon of insertion may give rise to a sUp inserted on the first metacarpal (in 2 out of 85 bodies — Le Double) or into the terminal phalanx. Its tendon is often united with that of the long extensor. It may be fused with the long abductor of the thumb and has been found missing. It may be doubled.
The extensor pollicis longus (fig. 369). — Origin. — From the middle third of the lateral part of the dorsal surface of the ulna; from the neighbouring part of the interosseous membrane; and from the septa between it and the extensor indicis proprius, and the extensor carpi ulnaris.
Structure and insertion. — The fibre-bundles converge in a bipenniform manner on the two sides of a tendon which appears high on the dorsal surface of the muscle. They extend as far as the dorsal carpal (posterior annular) hgament. The fusiform body of the muscle descends somewhat obliquely on the dorsal surface of the forearm. The tendon enters the third osteofibrous canal beneath the dorsal carpal (posterior annular) Hgament. On emerging from the canal it passes very obliquely across the dorsal surface of the carpus, over the tendons of the radial extensors, to the ulnar side of the first metacarpal. It passes along this and on the dorsal surface of the first phalanx, expands to be inserted into the base of the second phalanx. The aponeurosis of insertion receives tendinous slips from the short muscles of the volar surface of the thumb.
Nerve-supply. — By a twig from the deep radial (posterior interosseous) nerve. The branch gives rise to twigs which enter the proximal third of the radial border of the muscle. The fibres arise from the sixth, seventh, and eighth cervical nerves.
Action. — To extend the second phalanx on the first, and this on the metacarpal. It also draws the whole thumb when extended toward the second metacarpal. It may have a sUght supinator action on the forearm.
Relations. — The head of the muscle is partly overlapped by the long abductor of the thumb. It lies between this and the extensor pollicis brevis on one side, and the extensor indicis proprius on the other. Over it lie the extensors of the fingers and the ulnar carpal extensor.
Variations. — The tendon may give a slip to the base of the first phalanx of the thumb, to the dorsal carpal hgament, or to the index finger. It may receive an accessory slip from the common extensor of the fingers or the short extensor of the thumb. It is frequently! doubled. An additional extensor is found in about 6 per cent, of bodies between the extensor! of the index finger and that of the thumb. It has a double tendon and insertion into both digits (extensor communis pollicis et indicis).
The extensor indicis proprius (fig. 369). — Origin. — From the proximal part of the distal third of the posterior surface of the ulna, medial and distal to that of the preceding muscle, from the adjacent interosseous membrane, and from the septum between it and the extensor pollicis longus.
Structure and insertion. — The fibre-bundles are inserted on a tendon which first appears on the radial border of the muscle. The insertion of fibre-bundles extends nearly to the dorsal carpal (posterior annular) ligament. Here the tendon passes beneath that of the extensor of the little finger and enters the fourth osteo-fibrous canal beneath the lateral tendons of the common extensor. It passes across the wrist beneath the tendon from the extensor communis to the index finger, and is inserted on the ulnar side of this into the dorsal aponeurosis of the index finger opposite the base of the first phalanx.
Nerve-supply. — By a twig from the deep radial (posterior interosseous) nerve. This twig enters the proximal third of the radial border of the muscle. It frequently arises from a branch to the extensor pollicis longus. The nerve fibres come from the sixth, seventh, eighth cervical nerves.
Variations. — These are frequent. It may be absent. There may be two heads, or the muscle may be completely doubled. It may receive an accessory slip from the ulna or the carpus. The tendon may give accessory slips to the middle finger, the ring finger, or the thumb. The accessory tendon to the middle finger is the most frequent. The tendon to the index finger may be inserted on the metacarpus.
Abnormal Muscles of the Back of the Wrist and Hand
The extensor medil digiti is a small muscle which arises from the ulna beneath the extensor of the index finger, with which it is more or less fused. It sends a tendon to the extensor aponeurosis of the middle finger or slips both to this finger and the index finger. It is present in about 10 per cent, of bodies (Le Double).
The extensor digitorum brevis, which resembles the muscle of corresponding name on the dorsum of the foot, may have from one to four fascicuU, but most frequently one. The most common fasciculus is one which sends a tendon to the extensor tendon of the index finger. One for the middle finger is nearly as frequent. Others are rare. A fasciculus for the thumb has not been reported. (Le Double.) The fasciculi usually arise from the bones of the ulnar half of the carpus — lunatum (semilunar), triquetrum (cuneiform), hamatum (unciform), and capitatum (magnum), and from the dorsal ligaments uniting these bones. The tendons are inserted either into the corresponding extensor tendons or into the metacarpals. The muscle is found in about 10 per cent, of bodies (Wood).
B. m. abductoiis pollicis longi. — Between the tendons of the long and short radial extensors and the tendons of the abductor pollicis longus and extensor pollicis brevis. Another bursa lies beneath the tendon of insertion of the abductor.
Vagina tendinum mm. extensorum carpi radialium. — Synovial sheaths cover the tendons of the two radial carpal extensors as they pass beneath the dorsal carpal (posterior annular) ligament. In the adult these sheaths usually are more or less fused and communicate with the sheath of the extensor pollicis longus where this crosses them.
Vagina tendinum mm. extensoiis digitorum communis et extensoris indicis. — A synovial sheath surrounds the tendons of these muscles as they pass beneath the dorsal carpal (posterior annular) ligament. This sheath extends for some distance on the tendons as they diverge.
the lateral surface of the middle third of the shaft of the radius; the fusiform flexor carpi radialis sends a tendon to the base of the second metacarpal; the slender palmaris longus is inserted into the palmar fascia; and the medially situated, fusiform flexor carpi ulnaris into the pisiform bone and the palmar fascia. The pronator teres is the most powerful pronator of the forearm. When
the hand is slightly flexed the ulnar carpal flexor abducts ulnarward. When the hand is greatly flexed lateral movement is difficult. The ulnar flexor is supplied by the ulnar nerve, the other muscles by the median.
The pronator teres probably corresponds with the pophteus of the leg. The flexor carpi radialis and flexor carpi ulnaris probably represent in the main the two heads of the gastrocnemius, and the palmaris longus, the plantaris.
The pronator teres (fig. 370}. — Origin. — By two heads: — (1) The humeral or chief head arises by a tendon from the superior half of the ventral surface of the medial epioondyle and directly from the overlying fascia and from the intermuscular septa between it and the medial
PRONATOR TERES
head of the triceps and the flexor carpi radialis. (2) The ulnar, deep or accessory, head arises by an aponeurotic band attached to the inner border of the coronoid process medial to the tendon of the brachialis. Between the humeral and ulnar heads is a fibrous arch beneath which the median nerve passes.
Extensor pollicis brevis
surface along the radial border. The tendon gradually becomes broader, winds about the volar surface of the radius, and is inserted into the middle third of its lateral surface. The attachment of fibre-bundles continues nearly to this insertion. The fibre-bundles of the ulnar head form a slender fasciculus which is inserted into the radial side of the deep surface of the humeral head.
Nerve-supply. — By a branch derived from the median nerve before it passes between the two heads of the muscle. The nerve enters the proximal part of the middle third of the main belly of the muscle on its deep surface near the radial border. The branch to the ulnar head usually enters this portion of the muscle somewhat proximal to its fusion with the humeral head. The nerve fibres arise from the sixth and seventh cervical nerves.
Relations. — The muscle is superficially placed. Near its origin it is covered by the lacertus fibrosus of the biceps, and near its insertion by the radial vessels and nerve and the brachioradialis and radial extensor muscles. It is the most radial of the group of muscles under consideration. The radial border helps to bound an angular space, the cubital fossa, in which lie the brachial vessels, median nerve, and the tendon of the biceps. The median nerve passes between its humeral and ulnar heads. The muscle overlies the supinator, the brachialis, and the radial origin of the flexor digitorum sublimis muscles and the ulnar artery.
Variations. — Supplementary fasciculi may arise from the humerus, the medial intermuscular septum of the arm, the flexor carpi radialis, the flexor sublimis, or the brachiahs muscles. The two portions of the muscle may be distinct from origin to insertion. Either part of the muscle may be doubled. The ulnar head may be absent. The radial insertion may be extensive. Fasciculi may extend to the long flexor of the thumb. There may be a sesamoid bone in the tendon of origin from the humerus.
The flexor carpi radialis (fig. 370). — Origin. — From (1) the common tendon attached to the medial epicondyle; and (2) the septa between its head and the pronator teres, the flexor sublimis, and the palmaris longus.
Structure and insertion. — The fibre-bundles descend to converge upon a tendon at first intramuscular, but which in the middle of the arm appears on the vblar surface of the muscle and soon becomes free from the attachment of fibre-bundles. The fibre-bundles from the epicondyle descend nearly vertically to the front and sides of the tendon, while those from the intermuscular septa take an oblique course to the deep surface of the tendon. The tendon is at first flat, but soon becomes cylindrical, bound to the superficial muscle fascia, and enters the hand through a special osteo-fibrous canal formed mainly by the groove in the os multangulum majus (trapezium) and the transverse carpal (anterior annular) ligament. It is inserted into the base of the second metacarpal. It usually also sends a tendon slip to the third.
Nerve-supply. — By a branch from the median nerve which divides into several twigs that enter the muscle near the junction of its proximal and middle thirds on the deep surface. The nerve usually arises near the elbow. The nerve fibres arise from the sixth, seventh (and eighth) cervical nerves.
of the forearm and a flexor of the forearm on the arm.
Relations. — It is superficial except near its insertion. The belly of the muscle lies between the pronator teres and the palmaris longus and upon the flexor digitorum sublimis. The tendon of the muscle passes over the flexor poUicis longus, and near the wrist is a guide to the radial artery, which here lies lateral to it. In the hand the tendon lies beneath the thenar muscles and is crossed by the tendon of the long flexor of the thumb.
Variations. — It may receive a fasciculus from the brachiahs or biceps muscles or from the radius or ulna. It may send tendon slips to the multangulum majus (trapezium), navicular, the transverse carpal (anterior annular) hgament, or the fourth metacarpal. The insertion may take place variously into these structures.
medial epicondyle and from the surrounding intermuscular septa.
Structure and insertion. — The fibre-bundles take a nearly parallel course to a tendon which appears high in the middle third of the forearm on the volar surface of the muscle. In the middle of the forearm the attachment of fibre-bundles usually ceases, the tendon becomes bound to the overlying fascia, and descends paraUel with that of the radial flexor. Near the proximal border of the transverse carpal (anterior annular) ligament the tendon expands into radiating bundles of fibres of which the medial and lateral are attached to the fascia over the intrinsic muscles of the thumb and little finger, while the middle, much more developed, constitute the chief portion of the palmar aponeurosis.
Nerve-supply. — From a branch which usually arises in company with the nerve to the proximal part of the flexor sublimis. It frequently traverses the superficial fibres of the flexor sublimis. The nerve enters the middle third of the muscle.
In the distal part of the forearm the tendon lies over the median nerve.
Variations. — It is absent in 11.2 per cent, of instances (Le Double). It may be highly developed or reduced to a tendinous band. The belly of the muscle may lie in the distal instead of in the proximal part of the forearm. It may be digastric. It may be fused with neighbouring muscles. It may arise from the medial intermuscular septum of the arm or from the lacertus fibrosus, from the radius, from the coronoid process, from the radial or ulnar flexor, or from the flexor sublimis muscles. The tendon may terminate in the fascia of the forearm, the thenar eminence, the carpus, or the abductor of the thumb. The muscle may be partly or wholly doubled.
The flexor carpi ulnaris (fig. 370). — Origin. — By two heads: — (1) the humeral head arises from the common flexor tendon attached to the lower ventral part of the medial epicondyle Fibre-bundles of this head are also attached to the surrounding intermuscular septa and the deep fascia of the forearm. (2) The ulnar head arises by short tendinous fibres from the medial side of the olecranon and by an aponeurotic band common to it and the flexor digitorum profundus from the upper two-thirds of the dorsal border of the ulna. Proximally the two heads of the muscle are united by a fibrous arch extending from the olecranon to the medial epicondyle. Beneath this band pass the ulnar nerve and the dorsal recurrent ulnar artery. (See Epitrochleo-olecranonis, p. 402.)
Structure and insertion. — The fibre-bundles of the humeral head descend nearly vertically, those of the ulnar head obliquely distally in a radial direction. They are iiiserted in a penniform manner on a tendon which appears in the proximal part of the middle third of the belly of the muscle on the radial margin of the deep surface, and in the distal third of the forearm forms the radial border of the muscle. On the ulnar side the insertion of fibre-bundles continues nearly
FLEXOR DIGITORUM SUBLIMIS 399
to the pisiform bone. The insertion of the tendon takes place chiefly into the pisifoi'in bone, but from it tendinous bundles extend to the palmar aponeurosis, volar ligament of the carpus, to the pisohamate ligament (pisi-unciform), and to the bases of the fifth, fourth, and third metacarpals.
Nerve-supply. — From two or three branches of the ulnar nerve, the most pro.ximal of which arises near the elbow-joint. These branches, which may arise by a single trunk, enter the deep surface of the proximal third of the muscle and send long twigs distally across the middle third of the constituent fibre-bundles. The nerve fibres arise from the seventh and eighth cervical and first thoracic nerves.
Relations. — It is superficially placed. Its aponeurotic origin is adherent to the fascia of the forearm. It lies medial to the palmaris longus and flexor sublimis and upon the flexor profundus. Beneath the muscle lies the ulnar nerve. The ulnar artery extends along the radial border of the tendon near the wrist.
b. Second Layer
This is composed of one muscle, the flexor digitorum sublimis, which, although in part covered by the muscles of the preceding layer, is in part superficial. It arises from the medial epicondyle of the humerus, and from the radius and the ulna, and sends tendons to the second row of phalanges of the fingers. It corresponds probably with the soleus and the tendons of the flexor digitorum brevis in the leg and foot.
The flexor digitorum sublimis (figs. 371, 373, 375). — Origin. — By two heads: the ulnar or chief head arises (1) by the tendon common to it and the superficial group of muscles from the medial epicondyle, and by short tendinous bands from the ventral surface of the epicondyle; (2) from the ulnar collateral ligament of the elbow, the ulnar tuberosity, the medial border of the coronoid process, and the inferior extremity of the tendon of the brachialis; and (3) from the intermuscular septum between the flexor subhmis and the overlying muscles. The radial head arises from an oblique line on the volar surface of Ijje radius, and from the middle third of the anterior border.
the fingers.
Structure. — The fibre-bundles of the ulnar head and the upper part of the radial head converge, the ulnar fibre-bundles nearly vertically, the radial obliquely, to form a common belly the deep surface of which on the ulnar side is backed by a dense tendinous band. On the radial side of this a less dense membrane covers over an oval canal which passes distally along the line of junction of the two heads and lodges the ulnar artery and the median nerve.
The fibre-bundles of the ulnar head form a superficial and a deep group. The superficial portion near the middle of the forearm divides into a lateral and a medial division, the former being inserted on a tendon that goes to the middle and the latter on one that goes to the ring finger. The fibre-bundles of the radial head join with the lateral division of the superficial layer of the ulnar head and are inserted on the tendon of the middle finger nearly as far as the wrist. A small muscle fasciculus of the superficial portion of the ulnar head is usually united by a tendon to the long flexor of the thumb.
The deep portion of the ulnar head about the middle of the forearm terminates in large part on the volar surface of the dense tendinous band above mentioned. From this in turn two muscle bellies arise. One of these is inserted in a bipenniform manner on a tendon going to the index finger, the other on a tendon going to the little finger. A muscle fasciculus also usually passes from the region of the tendon band to that portion of the superficial fasciculus which terminates on the tendon of the ring finger.
The four tendons pass together through the carpal canal under the transverse carpal (anterior annular) ligament, those to the middle and ring fingers lying at first superficial to the other two. The tendons then diverge, and each tendon, together with and above a tendon of the flexor profundus, passes over the metacarpo-phalangeal joint into an osteo-fibrous canal on the palmar surface of the first phalanx of the finger for which it is destined. Here the tendon becomes flattened about the round tendon of the flexor profundus. Opposite the middle of the phalanx the tendon divides into two slips, between which the tendon of the flexor profundus passes. The divided halves of the sublimis tendon fold about the profundus tendon so that their lateral edges come to meet in the mid-line beneath this tendon opposite the phalangeal joint (figs. 375, 376). They then again separate, extend distally, and are attached one on each side into a ridge at the middle of the lateral border of the second phalanx. The tendons are also attached by vincula tendinum, a ligamentum breve, between the tendon and the head of the first phalanx and the joint, and a ligamentum longum, between the tendon and the volar surface of the first phalanx.
Nerve-supply. — Before the median nerve passes between the two heads of the pronator teres a branch arises which accompanies the nerve through the pronator and sends several branches into the proximal third of the ulnar head of the muscle. As the median nerve passes beneath the muscle, one or more branches are given to the radial head, and a long branch is given to the fasciculus of the second and from this one to that of the fifth digit. Occasionally, the median nerve in the distal third of the forearm gives rise to branches for these fasciculi. The nerve fibres arise from the seventh and eighth cervical and first thoracic nerves.
Relations. — The belly of the muscle is covered by the pronator teres, flexor carpi radialis, and palmaris longus, but is superficial along a narrow strip between the flexor carpi ulnaris and the palmaris longus, and on each side of the tendon of the flexor carpi radialis. The muscle rests on the flexor pollieis longus and flexor digitorum profundus, the median nerve (see description given above) and ulnar vessels. The median nerve emerges from beneath the radial border of the muscle in the lower third of the forearm. In the palm the tendons lie beneath the
pahnar aponeurosis, the superficial palmar arch, and the branches of the median nerve, while they lie in front of the tendons of the fle.xor profundus, with which they are closely associated into a common bundle by loose fibrous tissue. The digital relations of the tendons are described above.
Variations. — The whole muscle may be rendered digastric by a transverse tendon. A fasciculus of the flexor sublimis may replace the palmaris longus or the two may coexist. A fasciculus may terminate in the fascia of the forearm or in the transverse carpal ligament, the palmar aponeurosis, etc. Various parts of the muscle may be absent or more independent than usual. The extent of the radial attachment varies greatly and may be missing. A special fasciculus may be received from the coronoid process of the ulna. A fasciculus may be sent to the flexor profundus or to other muscles. There may be some fusion with neighbouring muscles.
The two muscles which constitute this layer may be looked upon as differentiated from a single deep flexor muscle. The flexor digitorum profundus is a strong, broad muscle which arises from the upper three-fourths of the volar surface of the ulna and gives rise to tendons which are inserted into the bases of the third row of phalanges of the fingers. The flexor pollicis longus, likewise broad and flat, arises from the volar surface of the radius and is inserted into the base of the second phalanx of the thumb. Both muscles are supplied by the median nerve and the flexor profundus is also supplied by the ulnar nerve.
cis longus of the leg.
The flexor digitorum profundus (figs. 372-,376). — Origin. — (1) Through an aponeurotic septum between it and the fiexor earpi ulnaris from the dorsal border of the ulna; (2) directly from the proximal two-thirds of the medial surface and the proximal three-fourths of the volar surface of the uhia and from the adjacent interosseous membrane; and (3) inconstantly, from a small area on the radius below the bicipital tuberosity.
Structure and insertion. — The fibre-bundles descend nearly vertically and give rise to a common belly which soon divides into four portions, each of which is attached about midway down the forearm in a semipennif orm manner to the dorsal surface of a tendon. The attachment of fibre-bundles continues nearly to the wrist. The digital divisions of the muscle vary in the height to which they extend. That belonging to the index finger is usually the one most exten-
sively isolated, and that to the little finger is the next most so. The tendons pass side by side under the transverse carpal (anterior annular) ligament, and then diverge to the bases of the fingers. At the metacarpo-phalangeal joints, they enter the osteo-fibrous canals described above (p. 387). On the volar surface of the first phalanx each tendon passes through the sht in the subhmis tendon. The tendon then is continued over the second phalanx to the base of the third. Vincula tendinum are described passing to the capsule of the second interphalangeal joint (ligamentum breve) and to the tendon of the flexor subhmis (ligamentum longum). The lumbrical muscles arise from the tendons while they are in the palm.
Nerve-supply. — The interosseous branch of the median nerve arises usually before the nerve passes through the pronator teres and accompanies the main trunk. This branch as it passes beneath the flexor sublimis gives off a branch (or two) from which several twigs spring. These twigs enter the muscle near the radial border and pass in across the middle third of the constituent fibre-bundles of the fasciculi to the index and middle fingers. The ulnar nerve near the elbow gives rise to a branch which enters the volar surface of the muscle near the junction of the proximal and middle thirds of that portion of the belly, giving tendons to the ring and little fingers. There is some variation in the extent of the innervation by the branches of the ulnar and those of the median nerve. To a greater or less extent through anastomosis their territories overlap. The nerve fibres arise from the seventh and eighth cervical and first thoracic nerves.
Action. — To flex the terminal phalanx of each finger on the second and the second on the first, while that of the superficial flexor is to flex the second phalanx on the first. The action of the two flexors on the first phalanx is somewhat more limited. The interosseous muscles, aided by the lumbricals, are the chief flexors of the first row of phalanges. The flexor profundus acts, though not powerfully, as a flexor of the wrist.
Relations. — The flexor profundus muscle lies beneath the flexor sublimis and the flexor carpi ulnaris muscles, the median nerve, and the ulnar vessels and nerve. Under the muscle lie the ulna, the interosseous membrane, and the pronator quadratus muscle. Under the transverse carpal (anterior annular) ligament the tendons lie beneath those of the flexor sublimis in the same synovial sac. In the palm the tendons with the associated lumbrical muscles lie upon the interosseous muscles, the adductor of the thumb, and the deep palmar arch, and beneath the flexor sublimis tendons. For the relations to the synovial bursse see p. 403.
Variations. — There is considerable variation in the extent of the radial origin and in the extent of the independence and fusion of the different fasciculi. In the prosimians a common tendon extends as far as the hand. The division in the higher forms is associated with refinement of movements of the fingers. One or more special fasciculi not infrequently join the muscle from the flexor sublimis, the flexor pollicis longus, the medial epicondyle, or the ulna. The accessorius ad flexorem digitorum profundum is a fasciculus which arises from the coronoid process of the ulna and sends a tendon to join the tendon of one of the fingers, most frequently the middle or index. It is found in 20 per cent, of bodies.
The flexor pollicis longus (fig. 372). — Origin. — The attachment extends along the oblique line and the ventral border of the radius from slightly below the bicipital tuberosity to within 5 cm. of the wrist. Medially it is continued into the interosseous membrane. Proximally the tendon frequently extends to the distal radial margin of the coronoid process of the ulna and gives rise to fibre-bundles connected with the muscle, as well as to a fasciculus of the flexor profundus.
Structure and insertion. — The fibre-bundles descend obliquely to be inserted in a penniform manner on a tendon which begins high up on the volar surface near the ulnar border of the muscle, and descends as a broad band which near the wrist becomes cyhndroid. The insertion of fibres continues nearly to the point where the tendon passes under the transverse carpal ligament. Here the tendon enters the carpal canal radial to the tendons of the flexor profundus, and passes beneath the superficial head of the short flexor of the thumb, then between the thumb sesamoids into the osteo-fibrous canal of the thumb, in which it is continued to the base of the terminal phalanx.
Nerve-supply. — Usually from two branches of the volar interosseous ramus of the median nerve. These enter the proximal half of tlie ulnar margin of the muscle. The nerve fibres arise from the sixth, seventh (and eighth) cervical nerves.
Relations. — It lies beneath the flexor subhmis, the flexor carpi radialis and brachio-radialis muscles, and the radial artery. Near the wrist it crosses over the insertion of the pronator quadratus. In the hand the tendon runs beneath the opponens pollicis and the superficial head of the flexor brevis, and across the deep head of the latter.
Variations. — It may be fused or united by fasciculi with the flexor profundus, the flexor subhmis, or the pronator teres. It may be partially doubled, giving rise to an accessory tendon which extends to the index finger. The origin may extend to the medial epicondyle of the humerus (epitrochlear bundle).
fourth of the ulna.
Structure and insertion. — From the ulna a strong aponeurosis extends a third of the way across the volar surface of the muscle. From this membrane and from the bone fibre-bundles extend transversely to be inserted on the distal quarter of the volar surface of the radius and on the triangular area above the ulnar notch. The deeper fibre-bundles which arise directly from the ulna are inserted into the radius by means of an aponeurosis. The superficial and deep portions of the muscle are often separated. The muscle is thicker distally than proximally.
Nerve-supply. — The volar interosseous nerve descends along the interosseous membrane, passes behind the middle of the proximal margin of the muscle, and sends branches into its deep surface. The nerve fibres arise from the (sixth), seventh and eighth cervical and first thoracic nerves.
Relations. — The muscle lies immediately beneath the muscles of the third layer and upon the radius and ulna, the interosseous membrane, and radio-ulnar joint. The radial artery and ulnar nerve pass in front of it, the volar interosseous artery behind it.
Variations. — It may be missing or may extend further up the forearm than usual or down upon the carpus. It may be triangular or divided into parts the fibre-bundles of which take different directions. It may send fasciculi to the carpus or metacarpus or be fused with the flexor carpi radialis brevis (see below).
The epitrochleo-olecranonis (anconeus internus). — A muscle fasciculus, distinct from the distal margin of the triceps, which runs from the medial epicondyle to the olecranon over the groove for the ulnar nerve, by a branch of which it is supplied. It takes the place of the fibrous arch normally extending between the epicondylar and ulnar heads of the flexor carpi ulnaris. It occurs in about 25 per cent, of bodies (Testut), and represents an adductor of the olecranon of the lower mammals. Occasionally the medial head of the triceps may descend over the ulnar groove, but this forms another type of muscle variation.
The flexor carpi ulnaris brevis (ulno-carpeus). — An abnormal muscle which arises from the distal quarter of the volar surface of the ulna and is inserted into the hamatum (unciform), the pisiform, the abductor of the little finger, or the superior extremity of the fifth metacarpal.
The unci-pisiformis. — A short, thick band of muscle which runs from the pisiform to the tip of the hamulus of the os hamatum (unciform) parallel with the pisohamate (pisi-unciform) ligament. It is innervated by the ulnar nerve.
The flexor carpi radialis brevis (radio-carpeus). — An abnormal muscle found in about 5 per cent, of bodies (Le Double). It arises from the lateral or the volar surface of the distal half of the radius. Some of the fibre-bundles may spring from the pronator quadratus, the fascia of the forearm, or the ulna. It is inserted into the carpus or metacarpus, and occasionally even into the first phalanx of the index finger, etc. It is supplied by a branch of the volar interosseous nerve. It serves to flex the wrist. It is said to represent the tibialis posterior of the leg.
A bursa is often found between the tendon of the deep flexor of the index finger and the carpus. This bursa is frequently in communication with the radial and ulnar tendon sheaths. A bursa is also often found between the deep and superficial tendons of the index finger.
transverse carpal ligament.
Vaginae tendinum mm. flexorum digitorum. — The osteo-fibrous canals of the digits are lined by a synovial membrane which is reflected by means of a fold (oul-de-sac) to the^tendons at each end and over the vincula tendinum, in which blood-vessels and nerves for the tendons are contained. The synovial cavity of the first and usually that of the fifth digit communicate with those of the palm.
number may be raised to five or reduced to one.
The radial sac, vagina tendinis m. flexoris pollicis longi, surrounds the long flexor tendon of the thumb in the wrist and palm and usually communicates with that of the thumb. In the palm a well-marked mesotendon usually extends to the deep ulnar side of the tendon from the parietal layer of the sheath.
The ulnar sac, vagina tendinum mm. flexorum communium, surrounds the tendons of the long flexors of the fingers. It begins proximal to the transverse carpal ligament and extends nearly or quite to the synovial sheath of the little finger on the ulnar side and on the radial side to the centre of the palm.
The ulnar nerve supplies the muscles of the little finger, the interossei, the medial lumbrical muscles, and two of the muscles of the thumb; the median nerve supplies most of the muscles of the thenar region and the lateral lumbrical muscles.
The palmaris brevis is a small, trapezoid sheet situated between the hypothenar fascia and the skin. It arises at the lateral edge of the palmar aponeurosis from tendinous slips which may be traced through the aponeurosis to the navicular and greater multangular. It is composed of nearly parallel fibre-bundles, and extends into the deep surface of the skin along the ulnar border of the palm. It is generally taken to be a subcutaneous muscle like the superficial muscles of the head and neck. It has, however, been suggested that it represents the remnants of a short flexor of the digits corresponding with the flexor digitorum brevis of the foot.
Nerve-supply. — The superficial branch of the palmar division of the ulnar nerve gives rise to a twig which enters the deep surface of the muscle. The fibres come from the (seventh and) eighth cervical and first thoracic nerves.
Action. — The action of the muscle is to draw the skin of the ulnar side of the hand toward the centre of the palm. It is said that it thus helps to form a cup-shaped hollow when the hand conveys fluid to the mouth. The contraction of the muscle by raising a ridge over the ulnar nerve and artery when an object is grasped hard serves, according to Henle, to protect these structures.
Variations. — It varies in size. In about 2 per cent, of bodies it is absent (Le Double). It may send tendinous slips to the pisiform bone. (For a thenar subcutaneous muscle, see variations of the abductor polhcis brevis.)
In the hypothenar eminence are three muscles, the abductor, the flexor brevis, and the opponens digiti quinti. The abductor digit! quinti is a flat, fusiform muscle which arises from the pisiform and is inserted into the ulnar border of the first phalanx and into the dorsal aponeurosis through which it helps to flex the first and extend the second and third phalanges of the little finger. The fusiform flexor brevis arises from the hamatum (unciform) and adjacent part of the transverse carpal (anterior annular) ligament and is inserted into the ulnar side of the base of the first phalanx. The triangular opponens likewise arises from the hamatum (unciform) and the transverse (anterior annular) ligament. It is inserted into the ulnar border and the head of the fifth metacarpal.
The abductor of the little finger corresponds with that of the little toe. A part of the opponens beneath the ulnar nerve corresponds with that of the little toe, while the more superficial portion is unrepresented in the foot. The flexor brevis of the httle toe corresponds with a part of the deep portion of the opponens of the little finger. The flexor brevis of the httle finger is unrepresented in the foot. (Cunningham.)
The abductor digiti quinti (figs. 375, 376). — Origin.— Yrom the distal half of the pisiform, the ligaments between this and the hamatum, the tendon of the flexor cai'pi ulnaris, and often from the transverse carpal (anterior annular) ligament.
Structure and insertion. — The fibre-bundles descend vertically, at first increasing in number and then concentrated, toward two short tendons one of which is inserted into the ulnar border of the first phalanx of the little finger and the other into the aponeurosis of the extensor tendon of the httle finger.
Nerve-suppbj. — From the deep palmar division of the ulnar nerve before it passes through the opponens, or from the superficial palmar branch, arise one or more twigs which enter the radia) side of the muscle on its deep sm'face in the proximal third. The nerve fibres arise from the (seventh and) eighth cervical and fu'st thoracic nerves.
Relations. — It overlies the opponens and flexor brevis. Superficially it is covered by fascia and the palmaris brevis muscle. Along the proximal part of its radial margin run the deep palmar branches of the ulnar artery and nerve.
the base of the first phalanx of the little finger. A sesamoid bone may lie in the tendon.
Nerve-supply. — A branch from the superficial or deep palmar division of the ulnar nerve enters the deep surface of the muscle in its proximal half. The nerves to the abductor and flexor may arise in common from the ulnar. The nerve fibres arise from the (seventh and) eighth cervical and first thoracic nerves.
lies the opponens.
Variations. — The muscle may be wanting or may be closelj' fused with the abductor or the opponens. It may receive an accessory slip from the forearm fascia. It may give a tendon sUp to the extensor aponeurosis or to the head of the fifth metacarpal.
Structure and insertion. — The fibre-bundles diverge, the proximal short and horizontal, the distal long and oblique, and are inserted on the whole of the ulnar border and on a part of the head of the fifth metacarpal. Often the^musole is divisible into two portions between which the ulnar nerve runs.
Nerve-supply. — Before the deep palmar branch passes through the muscle it gives rise to a twig which enters its volar surface in the middle third near the ulnar margin. The nerve fibres arise from the (seventh and) eighth cervical and first thoracic nerves.
Relations. — The opponens lies beneath the abductor and flexor brevis muscles. The deep branches of the ulnar nerve and artery pass through the opponens near its carpal origin and then under it extend into the palm.
The tensor capsularis articulationis metacarpo-phalangei digiti quinti is a slender muscle which arises from the ligaments which unite the pisiform to the hamatum, and is inserted into the volar surface of the metacarpo-phalangeal joint of the little finger.
In the therar region there are four muscles. Of these, the abductor pollicis brevis is the most superficial. Then come the opponens pollicis and the short flexor, and beneath the last the adductor pollicis. All are triangular in form. The abductor pollicis brevis arises from the radial side of the volar surface of the
carpus and is inserted into the radial side of the base of the first phalanx of the thumb. The opponens is a thick muscle extending from the transverse carpal (anterior annular) ligament to the radial side of the first metacarpal. The flexor poUicis brevis arises by two heads, a "deep" and a "superficial" from the carpus and is inserted into the radial side of the base of the first phalanx. The adductor poUicis arises from the carpus and the second and third metacarpals and is inserted into the ulnar side of the first phalanx of the thumb. From the tendons of insertion of the abductor and flexor brevis slips are continued into the dorsal aponeurosis of the thumb so that they aid in extending the second phalanx.
the last two muscles are not perfectly homologous in the hand and foot.
The abductor pollicis brevis (fig. 375). — Origin. — From the volar surface of the transverse carpal (anterior annular) ligament, and from the greater multangular bone (trapezium). Also often from the navicular bone and from a tendon slip of the long abductor.
Structure and insertion. — The fibre-bundles converge upon a flat tendon with two lamellae, the deeper of which is inserted into the radial side of the base of the first phalanx of the thumb and the superficial into the aponeurosis of the extensor poUicis longus.
Neroe-supply. — By a branch ot the first volar digital ramus of the median nerve. This branch passes over or through the flexor brevis and enters the muscle on the volar surface in the middle third near its ulnar border.
brevis and over the opponens. The superficial volar artery usually perforates the muscle.
Variations. — It may be wanting or may be divided into two divisions. The origin may extend to the fascia of the forearm or styloid process of the radius. It may receive an accessory slip from the long radial extensor, the opponens, or the short extensor of the thumb. A thenar subcutaneous muscle is occasionally present. It is narrow, is closely associated with the short abductor of the thumb, and extends from the radial side of the base of the first metacarpal into the skin of the thenar eminence.
Nerve-supply. — By a branch of the first volar digital ramus of the median nerve. This branch passes over or through the superficial division of the flexor brevis near the origin of the muscle. One or two twigs enter the deep surface of the proximal third of the opponens near its ulnar border. The nerve fibres arise from the sixth and seventh cervical nerves.
less fused with the short flexor.
The flexor poUicis brevis (figs. 376, 377). — The muscle is divided by the tendon of the long flexor into a superficial and a deep portion. The superficial head arises from the greater multangular bone (trapezium), the adjacent part of the transverse carpal (anterior annular) ligament, and the tendon sheath of the flexor carpi radialis. The fibre-bundles descend closely applied to the opponens, and terminate by a tendon which is attached to the lateral side of the front of the base of the first phalanx. Over the joint a sesamoid bone lies in the tendon. The deep head has a tendinous origin from the os multangulum minus (trapezoid) and the os capitatum (magnum). The fibre-bundles take an oblique course, to be inserted into the tendon of the superficial part. A muscle fasciculus which arises from the ulnar side of the base of the first metacarpal and the neighbouring carpal ligaments and is inserted on the ulnar side of the base of the first phalanx, is sometimes considered to be the deep head of the flexor brevis. It is closely bound up with the carpal head of the adductor poUicis and they have a common tendon. Some fibres of the medial division of the tendon may be traced into the aponeurosis of the extensor tendon. It is probable that this portion of the muscle represents a first volar interosseous, and it is so described later with the interosseous muscles. There is much dispute as to what fascicuU should be included in the flexor brevis.
Nerve-supply. — The muscle is usually suppUed by twigs derived from a branch from the first volar digital ramus of the median nerve as this branch passes through its substance, and by twigs from the deep branch of the ulnar. Brookes found this supply in 19 out of 29 instances, in 5 by the median alone, and in 5 by the ulnar alone. The nerve fibres come from the sixth and seventh cervical nerves.
Relations. — Proximally the short flexor is grooved for the tendon of the long flexor, beneath which more distally the deep head of the muscle passes laterally. The superficial portion of the muscle lies beneath the skin. The ulnar border of the deep head is fused prOximaUy with the adductor.
The adductor poUicis (fig. 377).- — Origin. — By two heads. The carpal or oblique head arises from the deep carpal ligaments, the capitatum and the bases of the second and third metacarpals; the metacarpal or transverse head, from the crest of the third metacarpal, from the suprametacarpal fascia of the third interspace, and sometimes also from that of the fourth interspace and from the capsules of the second, third, and fourth metacarpo-phalangeal articulations.
Structure and insertion. — The fibre-bundles converge toward a tendon which is inserted into the ulnar side of the front of the base of the first phalanx of the thumb. A sesamoid bone lies in the tendon over the joint.
Nerve-supply. — One or more twigs from the deep palmar branch of the ulnar enter the middle third of the muscle on its deep surface. There may also be an anastomosing branch from the median nerve. The nerve fibres come from the sixth, seventh and eighth cervical and first thoracic nerves.
When the thumb is in an extreme position of apposition, it acts as an abductor.
' Relations. — Superficial to the muscle lie some of the tendons of the deep flexor of the fingers and the first two lumbrical muscles. It extends over the two more lateral intermetacarpal spaces, and is in part subcutaneous on the dorsal surface. The deep palmar arch extends between the two heads and beneath the oblique head. The oblique head of the muscle is closely united to the first volar interosseous, so that the latter by some is considered a part of the adductor.
Variations. — The extent of the attachments of origin of the muscle vary considerably. The two heads of the muscle may be more or less completely separated from one another. Each may be divided into separate fasciculi.
From the deep flexor tendons in the palm of the hand arise the lumbrical muscles, four in number, which are attached by small tendons to the radial side of the extensor tendons (figs. 373, 375). These lumbrical muscles have homologues in the sole of the foot.
The lumbricales (figs. 375, 376). — Origin. — The two lateral arise from the radial side of the volar aspect of the first and second tendons of the flexor digitorum profundus; the two medial arise from the adjacent sides of the second and third and third and fourth tendons.
Structure and insertion. — The fibre-bundles of each muscle arise directly from the flexor tendons near the distal border of the transverse carpal (anterior annular) ligament. They converge as far as the metacarpo-phalangeal joint, upon a small tendon which begins about the middle of the muscle. The tendon passes out between the palmar aponeurosis and the transverse capitular ligament, winds about the metacarpo-phalangeal joint, expands, and is attached along the side of the first phalanx to the radial border of the tendon of the extensor digitorum communis. . j- , , ,
NerBe-supply. — Branches from the median nerve enter the middle third of the radial border of the first two or three lumbrical muscles. The last one or two are supplied by branches from the deep volar branch of the ulnar nerve, which enter the middle third of the deep surface. The third lumbrical and sometimes one or more of the others may receive a branch from both nerves. The nerve fibres come from the eighth cervical and first thoracic nerves.
toward the thumb.
Relations. — The muscles run between the tendons of the flexor profundus and beneath the palmar aponeurosis. They lie upon the fascia covering the interosseous muscles, the capitular ligaments, and the septum' over the adductor and deep head of the flexor pollicis brevis.
Variations. — These are very frequent, especially in case of the third and fourth. Each may be doubled or missing. They may arise from the tendons of the flexor subhmis or from the belly of the deep flexor. The first lumbrical may come from the tendon of the long flexor, from the opponens, or the metacarpal of the thumb. The tendon of insertion may go to the ulnar side of the base of the digit opposite that to which the tendon Is usually attached, or the tendon may divide and go to the adjacent sides of two fingers. Kopsch has found that in 110 bodies all four lumbricals were inserted on the radial side of their respective digits in 39 per cent. In 35 per cent, the first, second, and fourth were so inserted, while the third sent slips to the adjacent sides of the middle and ring fingers. An accessory fasciculus has been found to arise from the tendon of the flexor poUicis longus and go to the base of the index finger.
These muscles lie between the metacarpal bones and are covered dorsally and ventrally by fasciae attached to the metacarpals. In each interspace are two muscles, a dorsal and a palmaw The volar interossei are inserted into all the fingers
except the middle finger, and are adductors toward an axis passing through the middle finger; the dorsal interossei are inserted into both sides of the middle finger and into the radial side of the second and the ulnar side of the fourth finger, and are abductors. All also serve as flexors of the first row of phalanges and extensors of the second and third. In the foot the axis to and from which the interosseous muscles adduct and abduct the toes passes through the second toe.
others from three-fourths of the shaft. The fibre-bundles of each muscle converge in a penniform manner upon a tendon which is inserted into the aponeurosis of the digital extensor tendon and the base of the first phalanx on the middle finger side of the corresponding digit (see fig. 373). The first volar interosseous is often described as a division of the flexor poUicis brevis or of the adductor poOicis.
The interossei dorsales arise from the adjacent sides of the metacarpal bones in each interspace. On the sides nearest the middle finger they cover three-fourths of the bone, on the opposite sides much less. The fibre-bundles converge in a bipenniform manner upon a tendon which begins high in the muscle and is inserted into the aponeurosis of the extensor muscles and the base of the first phalanx on each side of the middle finger, on the thumb side of the index finger, and the ulnar side of the ring finger. The interosseous muscle in the first interspace is thick and strong and forms with the adductor poUicis the fleshy web between the base of the thumb and the palm.
Nerve-supply. — By branches of the deep palmar division of the ulnar nerve. As a rule, a branch to each volar interosseous enters the proximal third of the muscle. To each dorsal interosseous a branch is given which enters between the two heads. These branches may be variously combined before entering the interosseous muscles. The nerve fibres arise from the eighth cervical and first thoracic nerves.
axis, the dorsal from it.
Relations. — The volar interossei lie volarward from the dorsal interossei. The two sets of muscles are bound in place by the dorsal and volar metacarpal fascise. The tendons pass out on the dorsal side of the transverse capitular ligament and are closely apphed to the metacarpophalangeal joints. The muscles of the first two interspaces lie immediately dorsal to the adductor of the thumb; the others dorsal to the flexor tendons.
Variations. — The tendon slip from an interosseous muscle to the base of the first phalanx of a digit may be missing. This is more frequent in case of the volar than in that of the dorsal interossei, and in the medial than the lateral muscles. Either a volar or a dorsal interosseous muscle may be double or missing. Rarely the insertions of the interosseous muscles characteristic of the foot (see p. 499) may be found in the hand.
The spinal (vertebral) column is of special interest as the segmented longitudinal axial support of the body vsrhich has given rise to the term "vertebrates" as applied to the class of animals of which man is the highest form. The segmentation in fishes permits the lateral movements of the body which are their chief means of propulsion. In the land vertebrates, with the exception of snakes, the limbs are developed as the chief organs of propulsion but flexibility of the column
SPINAL MUSCULATURE 411
is retained for the sake of freedom of movement. In man the spinal column, with the exception of the sacral region, may be readily extended (bent backward) and flexed (bent forward), abducted (bent to the side) and rotated. Freedom of movement is greatest in the cervical and lumbar regions and is restricted by the thorax in the thoracic region. The cervical region allows considerable flexion, extension and rotation, but a more limited abduction. In the thoracic region rotation and abduction are freer than flexion and extension. The lumbar region is that in which the chief flexion and extension of the trunk takes place, but abduction and rotation are limited, especially the latter. In the isolated articulated spinal column freedom of movement of the various parts depends chiefly upon the thickness and elasticity of the intervertebral discs, upon the conformation of the articulat processes, and upon the elasticity or arrangement of the various ligaments uniting the vertebrae. In the living body freedom of movement is further restricted by the musculature and skeletal apparatus attached to the column. There is much individual variation in the flexibility of the vertebral column.
The various movements ot the column are produced partly by muscles which act directly on it and partly by muscles which act on it through the head, thorax or pelvis. Most of the muscles which act on it directly belong to the intrinsic dorsal musculature; that is, to musculature which is derived from the dorsal divisions of the myotomes and is innervated by the dorsal divisions of the spinal nerves. This musculature extends from the sacrum to*the skull and is closely applied on each side of the mid-dorsal line of the body to the backs of the vertebrae and the back of the thorax (fig. 381). Its chief function is to extend the spinal column and head, hence the old term applied to the superficial portion of this musculature "erector spinas. " During the development of the body, muscles belonging to the ventro-lateral thoracic musculature and to the upper extremity come to overlie in part the intrinsic dorsal musculature. The trapezius and rhomboid muscles which cover it in the cervical and thoracic regions, and the latissimus dorsi which covers it in the thoracic and lumbar regions belong to the shoulder girdle and arm and have already been described, p. 360. The serratus posterior superior, which overlaps it in the upper thoracic region, and the serratus posterior inferior, which overlaps it at the junction of the thoracic and lumbar regions, are derived from the intercostal musculature which is described below, p. 422 (fig. 380). All of these muscles are innervated by the ventro-lateral divisions of the spinal nerves. The levatores costarum (fig. 380), which extend from the transverse process of the thoracic vertebrae to the ribs, and which, in spite of their name, act chiefly on the spinal column, are derived from the external intercostal musculature and are innervated by the intercostal nerves.
Ventral to the spinal column and closely applied to it there are a few muscles, the chief function of which is to flex the column. All are supplied by branches from the ventro-lateral divisions of the spinal nerves. Of these the longissimus colli and longissimus capitis and scalene muscles have been described in connection with the muscles of the neck, p. 353. In the thoracic region there are no muscles of this type. In the lumbar region there are four muscles on each side, the pillars of the diaphragm, fig. 391, the psoas minor, fig. 391, the psoas major, fig. 391, and the quadralus lumborum, fig. 391. All of these muscles are flexors of the spine^ except the quadratus, which is an extensor. The psoas major muscle is also a flexor of the thigh. Even more powerful flexors of the column than those above mentioned are some of those which work indirectly upon it through the leverage offered by the skull (sterno-cleido-mastoid described above, p. 347), and the thorax (the ventro-lateral abdominal musculature).
leaving for consideration elsewhere the other musculature which acts on the vertebral column.
The intrinsic dorsal musculature is attached to the sacrum, to the ilium, to the spines, transverse, and articular processes and laminae of the lumbar, thoracic, and cervical vertebrae, to the backs of the ribs and to the base of the skull. Two great longitudinal subdivisions may be recognised, a lateral, supplied by lateral branches of the posterior divisions of the spinal nerves, and a medial, supplied by medial branches. The lateral portion is further divisible into a superficial division, consisting chiefly of systems of muscles extending laterally from the spines of the vertehv3d upward toward the transverse processes of the vertebrae, the ribs, and the mastoid process of the skull; and a deep division, consisting of muscles which extend between successive transverse processes. The medial portion likewise consists of two parts; a superficial medial composed of fasciculi extending from inferior to superior spines, best developed in the dorsal region, and a deep portion consisting mainly of muscle fasciculi which pass from the transverse processes upward toward the spines of vertebrae situated more cranially. In the neck the more superficial extend to the base of the skull. Between the base of the skull and the first two vertebrae there are several specialised muscles. There is also frequently present the rudimentary sacro-coccygeus posterior described on p. 448, which represents an extension into the caudal region of the intrinsic dorsal musculature.
The superficial lateral dorsal musculature consists of the splenius and the sacrospinalis. The splenius (fig. 380) is a flat, somewhat triangular muscle, which extends from the cervical and upper thoracic spines to the upper cervical transverse processes and to the mastoid process of the temporal bone and the neighbouring part of the occipital. The sacro-spinalis (erector spinte) (fig. 381) is the name given to a mass of musculature which takes its origin from the ihum, the sacrum, and the lumbar spines. In the lumbar region this muscle divides into its two chief portions, the ilio-costalis and the longissimus. The ilio-costalis (fig. 382) is attached to the lumbar transverse processes and to the ribs near the angles, and is continued upward by accessory fasciculi along the back of the thorax to the transverse processes of the cervical vertebrae. The longissimus (fig. 382) extends upward between the ilio-costalis and the spines of the lumbar and thoracic vertebree. It is attached to the transverse processes of the lumbar and thoracic vertebrae and to the ribs lateral to the transverse processes. It is continued to the transverse processes of the cervical vertebrae and to the skull by accessory muscle slips.
The deep lateral dorsal musculature consists of the dorsal intertransverse muscles. The intertransverse muscles are best developed in the cervical and lumbar regions. In the cervical region intertransverse muscles belonging to the dorsal musculature extend between the successive dorsal tubercles, while intertransverse muscles belonging to the ventral musculature extend between the ventral tubercles. The latter, as well as the rectus capitis anterior and rectus capitis lateralis, which belong in the series, have been described above (p. 356). In the lumbar region there are also two sets of intertransverse muscles, one belonging to the ventral and one to the dorsal musculature.
The superficial medial dorsal musculature consists of the spinalis dorsi and cervicis. The spinalis dorsi (fig. 381) is intimately fused with the longissimus. It extends from the lower to the upper thoracic spines, and is derived from the medial dorsal musculature. The inconstant spinalis cervicis, which extends from the upper thoracic to the lower cervical spines, is likewise derived from the medial dorsal musculature, but is less intimately related to the longissimus.
The deep medial dorsal musculature (fig. 383) lies in the groove between the transverse processes and the spines of the sacral, lumbar, thoracic, and cervical vertebrae. It extends from the sacrum to the skull, and is best developed in the lumbar and cervical regions. It is subdivided into a vertebro-occipital muscle (semispinalis capitis), a transverso-spinal group, and the interspinal muscles. The semispinalis capitis (complexus) (fig. 381) arises from the transverse processes of the third cervical to the sixth thoracic vertebrae and from the spines of the upper thoracic vertebrae and is inserted into the base of the skull. The transverso-spinal group (fig. 383) extends from the sacrum to the second cervical vertebra. It is more or less artificially divisible into several layers. In the superficial layer, the semispinalis dorsi et cervicis, which extends from the twelfth thoracic to the second cervical vertebra, the constituent fasciculi extend from the transverse process of one vertebra to the spine of a vertebra four to six segments above. In the middle layer, the multifidus, the fasciculi extend over from two to four vertebrae. In the deepest layer, the rotatores, the fasciculi extend to the ne.xt vertebra (short rotators) or to the second vertebra above (long rotators). The interspinal muscles extend between successive spines.
The muscles which pass from the first two vertebrae to the base of the skull behind, or suboccipital muscles (fig. 382), consist of the rectus capitis posterior minor, from the spine of the atlas to beneath the inferior nuchal line of the occipital and rectus capitis posterior major, from the spine of the epistropheus (axis) to beneath the inferior nuchal line, lateral to the preceding; of the obliquus capitis inferior, from the spine of the epistropheus (axis) to the transverse process of the atlas, and the obliquus capitis superior, from the transverse process of the atlas to the base of the lateral part of the inferior nuchal line of the occipital above the rectus major.
The primitive condition of the dorsal musculature is one of metameric segmentation. This is characteristic of fishes, many amphibia, and of the embryos of all higher vertebrates. In the tailless amphibia, however, a partial differentiation of the dorsal musculature takes place during embryonic development, and in all higher forms a differentiation takes place which corresponds in many ways to that described above for man. According to Favaro, the splenius is differentiatied from the medial dorsal system, but its innervation should place it with the lateral system. In the human embryo the dorsal segmental musculature extends into the tail region, but afterward here undergoes retrograde metamorphosis.
into two layers, of which the deeper is adherent to the lumbodorsal fascia.
The splenius (fig. 380) is enveloped in a thin, adherent fascial covering. The saoro-spinalis is covered by a fascia, the fascia lumbo-dorsalis (fig. 380), which inferiorly is attached to the iliac crest, the distal and lateral margins of the sacrum, and the sacral spines. In the lumbar and thoracic regions it is attached medially to the vertebral spines. Laterally, in the lumbar region, it is reflected around the muscle to its ventral surface, where a 'ventral' or 'deep' layer forms an intermuscular septum (fig. 384) between the quadratus lumborum and the sacrospinalis. This intermuscular septum (fig. 383) extends from the twelfth rib to the iliac crest and the ilio-lumbar ligament, and is attached medially to the transverse processes of the lumbar vertebra, from which fibre-bands extend laterally into it. It is strengthened above by fibrebundles which pass from the first and second lumbar vertebrce to the twelfth rib (lumbo-costal ligament). (For the relation of the abdominal muscles to this fascia see p. 328.)
In the thoracic region (fig. 384) the lumbo-dorsal fascia is attached to the ribs lateral to the iho-costal muscle. In the cervical region (fig. 351) the fascia is continued into the intermuscular septa which surround the muscles of this group in the neck.
which serves to separate them from the longissimus in the sacral, lumbar, and thoracic regions.
In the dorsal region of the neck (figs. 347, 351, 357) the muscles are covered on each surface by adherent fascial sheets, fascia nuchas, and are arranged in several concentric layers, each of which is separated from its neighbour's by dense fatty areolar tissue. The deepest of the layers is formed by the muscles of the transverso-spinal group. This is covered by a dense membrane, and is separated from the semispinalis capitis (complexus) by a thick layer of areolar tissue containing the chief blood-vessels and nerves of the neck. The semispinalis capitis (complexus) is covered on each surface by a more delicate adherent membrane, and is separated from the splenius by loose tissue. The splenius has a somewhat denser adherent fascial covering into which the fascia of the levator scapulse is continued. Separated from this by areolar tissue lies the trapezius. The cervical and thoracic portions of the semispinalis are separated by delicate membranous septa from the semispinalis capitis (complexus), the levator scapute, and the splenius. The muscles of each side are separated in the dorsal median plane by the dense ligamentum nuchae, into which the various cervical septa and fasciie extend. The suboccipital muscles are covered by fascial sheaths which are so fused as to constitute a special fascia for these muscles. Distally this is continued into the fascia of the transversospinal muscles.
and the supraspinous ligament of the third to the sixth thoracic vertebrae.
Structure and insertion. — The fibre-bundles extend upward and laterally and give rise to a flat muscle sheet from which fascicuh arise that are inserted by short tendinous processes on the posterior tubercles of the transverse processes of the first two or three cervical vertebrae. The processes are often united with those of the levator scapula? and the longissimus cervicis.
The splenius capitis. — Origin. — Froin the ligamentum nuchae in the region of the third to the seventh cervical vertebrae and from the spinous processes and the supraspinous ligament of the first two to five thoracic vertebrae.
Structure and insertion. — The fibre-bundles form a sheet which continues cranialward that of the splenius cervicis. The fibre-bundles converge somewhat and are inserted by a short, broad, thick tendon into — (1) the back, the side, and the tip of the mastoid process below the sterno-cleido-mastoid muscle, and (2) into the neighbouring part of the occipital bone.
Relations. — The splenius lies dorsal to the semispinalis capitis (complexus) and to the cervical (transversalis cervicis) and the cranial (trachelo-mastoid) portions of the longissimus and the cervical portion (cervicalis ascendens) of the ilio-costalis and to the levator scapulae, and is partly covered by the trapezius, sterno-cleido-mastoid, serratus posterior superior, and the rhomboids. In the triangle bounded by the trapezius, sterno-cleido-mastoid, and the levator scapulae it is subcutaneous.
placed. When both muscles act, the head and neck are extended.
Variations. — The extent of separation and of fusion of the two muscles varies. Absence of either muscle is rare. The splenius capitis may be divided into mastoid and occipital portions. The attachment of the muscle also varies somewhat. Occasionally the spinal origin of the splenius may extend to the cranial end of the ligamentum nuchae. The origin may extend laterally over the fascia covering the deeper dorsal muscles. An accessory slip, the splenius cervicis accessorius, separated from the main muscle by the tendon of the serratus posterior superior, is frequently (8 per cent, of instances, LeDouble) found to run from the lower cervical or upper thoracic vertebrae to the transverse process of the atlas.
The sacro -spinalis (erector spinas). — Origin. — (1) From a strong aponeurosis attached to the spines of the lumbar, and the sacral vertebrae, to the ligament passing from the sacrum to the coccyx, to the lateral sacral crest, the sacro-tuberous ligament, the long posterior sacro-ihac ligament, and to the dorsal fifth of the iliac crest; (2) directly from the iliac crest in front of and lateral to the attachment of the aponeurosis; and (3) from the short posterior sacro-iliac
ligaments. The aponeurosis covers the muscles of the sacral region and is there united to the overlying fascia by more or less dense areolar tissue. Opposite the iliac crest fibre-bundles begin to take origin from the lateral margin of the dorsal surface as well as from the deep or
ventral surface of the aponeurosis of origin, and gradually the line of dorsal attachment extends medially until, in the lower thoracic region, the tendon becomes completely embedded in the muscle-fasciculi which take their origin from it. The aponeurosis, which is the strongest in the lower lumbar region, is composed chiefly of fibres which take a direction upward and somewhat lateralward.
In the lower lumbar region the sacro-spinalis (erector spinae) muscle begins to show a distinct division into its two chief component parts, the ilio-costalis and the longissimus. The parts of which the ilio-costalis and longissimus are composed will be taken up separately. The ilio-costalis lumborum (figs. 381, 382). — Origin. — (1) Chiefly from the back of the sacrospinal aponeurosis, medial to and cranialward from the iliac crest, and (2) from the iliac crest directly. The deep medial surface of the muscle is closely united in the lumbar region to the longissimus.
Structure and insertion. — From the mass of fibre-bundles which compose the muscle, fasciculi are given off which are attached chiefly by tendinous slips to — (l)the tips of the transverce processes of the lumbar vertebrse; (2) the fibrous processes which extend lateralward from the tips of the transverse processes of the upper lumbar vertebrte into the anterior layer of the lumbodorsal fascia; (3) the inferior margin of the last six or seven ribs near the angles. The insertions into the lumbo-dorsal fascia and the twelfth rib are usually fleshy. The portions attached to the lumbar vertebrse are by some considered to belong to the longissimus (Eisler).
of the lower seven ribs medial to the angles.
Structure and insertion. — The slips of origin lie beneath the preceding portion of the muscle, pass medial to and partly fuse with it, and give rise to a belly from which tendinous shps extend to be inserted into the upper seven ribs near their angles and to the transverse process of the seventh cervical vertebra.
A bursa is frequently found between the muscle and the tubercle of the first rib. The longissimus dorsi (figs. 381, 382). — Origin. — (1) From the deep surface of the sacrospinal aponeurosis; (2) from the short posterior sacro-iliac ligaments; and (3) through accessory slips which arise from the transverse processes of the first two lumbar and the last five or six thoracic vertebrse. In the lumbar region it is fused dorso-laterally with the ilio-costalis.
Structure and insertion. — From the muscle mass arise fasciculi which are inserted partly directly, partly by means of tendons, into — (1) the lower border of the back of the transverse processes of the lumbar vertebrse and the inferior margins of the ribs lateral to the tubercles; and (2) the accessory tubercles of the lumbar and the tips and inferior margins of the transverse processes of the thoracic vertebra. The attachment to the first rib is usually wanting. The attachment to the first five ribs may fail. The medial attachments seldom extend to the first vertebra.
Relations. — The lateral margin of the muscle is covered by the ilio-costahs. Medially it overlies the transverso-spinal muscles. The lateral branches of the dorsal veins, arteries, and nerves pass mainly in the fibrous tissue which separates the longissimus from the ilio-costalis, the medial branches chiefly between the longissimus and the transverso-spinal muscles. The relations to the axio-appendicular muscles and to the dorsal fascia have been pointed out above. Ventrally it lies upon the intertransverse muscles, the external intercostals, and the levatores costarum.
transverse processes of the first four to six thoracic vertebrse.
Structure and insertion. — The fasciculi which arise from these slips give rise to a muscle belly from which tendons of insertion extend to the posterior tubercles of the transverse processes of the mid-cervical (second to sixth) vertebrse.
Nerve-supply of the sacro-spinalis. — From the lateral branches of the posterior divisions of the spinal nerves. The exact distribution of these branches is too complex to be treated here. The nerves for the ilio-costalis arise from the eighth cervical to the first lumbar, those for the longissimus from the first cervical to the fifth lumbar.
Action of the sacro-spinalis. — The sacro-spinalis serves, when acting on one side, to bend the spinal column toward that side, and when acting on both sides, to extend the spinal column. The cranial portions of the muscle serve to inchne the head toward the same side, and when both muscles act they serve to extend the head. The ilio-costalis muscle has the greatest power for producing lateral inclination. The ilio-costalis lumborum depresses the ribs, while the ilio-costalis cervicis (cervicalis ascendens) may aid in elevating them. The spinahs muscle serves merely as an extensor.
Variations of the sacro-spinalis. — The slips of origin and insertion of the various parts of this muscle and the extent of fusion of the various parts vary greatly. Statistical data from which the most frequent conditions might be determined are wanting. Tendinous inscriptions may extend across the longissimus cervicis and other parts of the sacro-spinaUs.
between the transverse processes of the cervical, lumbar, and the lower thoracic vertebrae.
(a) Ceroical (fig. 349). — Ventral, lateral and dorsal muscles are found in the cervical region. The ventral and lateral muscles run between the ventral tubercles and tips of the transverse processes of the vertebrae, are homologous with the intercostal muscles, are supplied by branches from the anterior divisions of the corresponding spinal nerves, and have been described above (p. 356). The dorsal muscles run between the dorsal tubercles and belong to the intrinsic dorsal musculature. They are supplied by the lateral branches of the posterior divisions of the cervical nerves.* The three sets of muscles are, however, more or less fused. The first pair of muscles extends between the atlas and axis, the lowest passes to the transverse process of the first thoracic vertebra, or to the first rib close to this. The obliquus capitis superior (described later) belongs, however, to the posterior set of muscles, the rectus capitis laigralis (p. 356) to the lateral set. The vertebral artery runs vertically between each pair of muscles above the sixth, and the anterior division of each cervical nerve passes laterally between the artery and the dorsal muscle in each space, and then out between the ventral and lateral muscles. The posterior division of each cervical nerve passes medial to each dorsal muscle.
(b) Thoracic. — Small muscle f ascicuh may extend between the transverse processes of the thoracic vertebrae and between the last thoracic and first lumbar. They are most frequent in the upper and lower thoracic regions. Often they are replaced by tendinous bands. In the second interspace the insertion may extend to the rib near the transverse process. The innervation is from the lateral branches of the posterior divisions of the spinal nerves.
(c) Lumbar (fig. 383). — In the lumbar region there is a lateral set of muscles connecting the adjacent margins of the transverse processes and a medial connecting the mammary tubercle of one vertebra to the mammary or the accessory tubercle of the vertebra next above. They extend between each two of the five lumbar vertebrae and sometimes also to the first sacral. They lie between the sacrospinalis and psoas muscles. The medial muscles are supplied by the lateral branches of the posterior divisions of the spinal nerves. The lateral muscles are supplied by branches from the junction between the two divisions of the corresponding spinal nerves. These branches probably belong to the anterior divisions.
and the last two thoracic spines.
Structure and insertion. — From the deep surface of the tendinous bands there arises a long slender muscle belly which is fused laterally with the longissimus dorsi. It is attached by tendinous processes to the spines of the upper thoracic vertebrae, usually the second or third to the ninth.
The spinalis cervicis. — A muscle of inconstant development which arises from the spines of the two upper thoracic and two lower cervical vertebrae and extends to the spines of the second to the fourth cervical vertebrae. The nerve supply is from the dorsal divisions of the lower cervical nerves.
structure.
Origin. — (1) By long tendinous fasciculi from the tips of the transverse processes of the upper five or six thoracic vertebrae and of the seventh cervical vertebra; (2) by short fleshy processes from the articular processes and bases of the transverse processes of the third to the sixth cervical vertebrae; and (3) by delicate fleshy fasciculi from the spinous processes of the upper thoracic vertebrae.
surface of the squamous portion of the occipital, between the superior and inferior nuchal hnes. There is often a transverse tendinous inscription across the muscle opposite the sixth cervical vertebra, and less frequently one between the upper and middle thirds of the muscle. These
SUBOCCIPITAL MUSCLES 419
Relations. — It lies dorso-lateral to the suboccipital muscles and to the semispinalis cervieis. From this latter it is separated by a septum containing the descending branch of the occipital artery, the deep cervical artery, and the medial dorsal branches of the cervical nerves. It is covered laterally by the longissimus capitis (trachelo-mastoid), and dorsally by the splenius, and above the upper margin of the splenius by the trapezius.
Variations. — The origin of the muscle may extend to the eighth thoracic vertebra or merely to the first thoracic. It may be fused with the longissimus (transversahs) cervieis. A special fasciculus may run beneath the muscle from the upper thoracic vertebrse to the head. The origin from the spinous processes of the thoracic vertebrse is not constant. The part of the muscle arising from this origin may be looked upon as a spinalis capitis.
2. Transversospinal Muscles
The semispinalis dorsi et cervieis (fig. 383). — This superficial transverso-spinal muscle sheet extends from the twelfth thoracic to the second cervical vertebra. The fasciciili which compose it arise by short tendons from the backs of the transverse processes, and are inserted by short tendons into the spines.
so in the thoracic.
Origin. — (1) From the groove on the back of the sacrum between the spines and the articular elevations, from the dorsal sacro-iliao ligaments, from the dorsal end of the Uiac crest, and from the deep surface of the aponeurosis of the sacrospinal muscle; (2) from the mammary and accessory processes of the lumbar vertebrae; (3) from the backs of the transverse processes of the thoracic vertebrae; and (4) from the articular processes of the fourth to the seventh cervical vertebrae and the back of the transverse process of the seventh.
Structure. — The more superficial fasciculi arise by short tendinous processes, the deeper ones directly. The more superficial fasciculi extend to the fourthor fifth vertebra above, the middle to the third, and the deepest to the second above.
The rotatores. — These, the third layer of transverso-spinal muscles, extend from the sacrum to the second cervical vertebra. They are composed of short fleshy fascicuh which extend to the second vertebra above (rotatores longi) and to the first above {rotatores breves). The fasciculi arise from the back and upper borders of the transverse processes or their homologues, and are inserted into the laminae of the preceding vertebrae. They are best developed in the thoracic region. Some authors consider the rotatores breves confined to the thoracic region. In the cervical region the fascicuU usually run from articulai- processes to the bases of the spines, in the lumbar region from the mammary processes to the caudal margin of the laminae of the arches.
The interspinales consist of short fasciculi which extend from the upper surface of the spiae of each vertebra near its tip to the lower surface of the spine of the vertebra above. In the neck the muscles lie in pairs between the bifid extremities of the vertebrae. In the lumbar region they form broad bands attached to the whole length of the spinous processes and are separated by the interspinous hgaments. In the thoracic region they usually are undeveloped.
Structure and insertion. — The muscle-fibres diverge to form a broad triangular band which is inserted into the lateral half of the inferior nuchal line of the occipital bone and the area below it. Its insertion is immediately below that of the obliquus superior.
Structure and insertion.— The fibre-bundles diverge to form a flat, triangular sheet inserted below the medial third of the inferior nuchal line of the occipital bone on the mfenor surface ot the squama occipitalis. .^ , , „ ^-^ -j c 4.1. ■ e
Structure and insertion.— The fibre-bundles diverge to form a flat, triangular muscle inserted into the lateral third of the inferior nuchal line of the occipital bone, and above the lateral part of the insertion of the rectus capitis posterior major.
IN THE Diagram.
The muscles of the body wall have been sUghtly pulled apart in order to reveal the relations of muscles, fasciae, and aponeuroses, a and 6 in the diagram indicate sections A and B, fig. 351 (p. 352); a- and 6^, sections A and B, fig. 357 (p. 366); a^" and 6', sections A and B, fig. 407 (p. 458):
1. Aorta. 2. Arteria mammaria interna. 3. Costa VI — a, cartilage. 4. Costa VII — a, cartilage. 5. Costa VIII. 6. Costa IX. 7. Costa X. 8. Costa XI. 9. Descending colon. 10. Diaphragm — a, costal portion; b, lumbar portion; c, sternal portion; d, centrum tendineum. 11. Fascia lumbodorsalis — a, anterior layer; b, posterior layer. 12. Fascia transversalis. 13. Flexura colica sinstra (splenic flexure). 14. Kidney. 15. Liver. 16. Linea alba. 17. Musculi intercostales externi — a, ligament. 18. Mm. intercostales interni. 19. M. iho-costalis. 20. M. latissimus dorsi. * 21. M. levator costee. 22. M. longissimus dorsi. 23. M. obUquus abdominis externus. 24. M. obhquus abdominis internus. 25. M. psoas major. 26. M. quadratus lumborum. 27. M. rectus abdominis. 28. M. serratus posterior inferior. 29. M. subcostalis. 30. M. transversus thoracis. 31. M. transversus abdominis. 32. Mm. transverso-spinales. 33. M. trapezius. 34. Nervus lumbalis I. 35. N. thoracalis VI. 36. N. thoracalis VII. 37. N. thoracalis VIII. 38. N. thoracahs IX. 39. N. thoracalis X. 40. N. thoracaUs XI. 41. N. thoracalis XII. 42. Sympathetic trunk — a, great splanchnic nerve. 43. Omentum majus. 44. CEsophagus. 45. Scarpa's fascia. 46. Spleen. 47. Stomach. 48. Ureter. 49. Vertebra lumbalis II. 50. Vert, lumbalis III. 51. Vert, thoracalis X.
Nerve-supply.- — These muscles are all supplied by the posterior branch of the suboccipital (first cervical) nerve. The branch to the two rectus muscles passes across the dorsal surface of the major rectus and supphes branches to the middle of the dorsal surface of each muscle. The branch to the superior oblique muscle enters the middle of the medial margin, that to the inferior oblique about the middle of its superior margin. The inferior oblique and major rectus muscles usually, the other muscles occasionally, receive branches from the second cervical nerve.
Relations. — The two oblique muscles with the rectus major serve to bound a small triangular space, the suboccipital triangle, through which pass the dorsal division of the suboccipital nerve and the vertebral artery. The two minor recti lie on the atlanto-occipital membrane in the upper part of the space bounded by the major recti. The muscles are covered medially by the semispinalis capitis (complexus), laterally by the longissimus and splenius capitis. In front of the two oblique muscles and the major rectus runs the vertebral artery. The great occipital nerve runs between the semispinalis capitis (complexus) and the inferior oblique and the two recti in a dense fatty connective tissue containing the extensive suboccipital venous plexus.
rectus major and the inferior obUque, when acting on one side, rotate the face toward that side.
Variations. — Each of these muscles may be doubled by longitudinal division. Accessory sUps may connect the two recti with the semispinahs capitis. The atlanto -mastoid is a small muscle frequently found. It passes from the transverse process of the atlas to the mastoid process.
The thoracic and abdominal viscera are contained within cavities, the ventrolateral walls of which may be contracted and expanded by muscular action. The skeletal support for the intrinsic musculature of these walls consists of the ribs, the sternum and the vertebral column and the pelvis. The intrinsic musculature in the thoracic walls is situated chiefly between the ribs {intercostal muscles, figs. 385, 386) while in the region of the abdomen it extends in broad sheets from the lower part of the thorax to the pelvis (the quadratus lumborum and the external and internal oblique, transverse, and reciws muscles, figs. 387, 388, 390, 406). Between the two cavities, attached to the lower part of the thorax and to the lumbar vertebrae lies the dome-shaped diaphragm (fig. 391). The thoracic cavity extends on each side slightly above the first rib. The abdominal cavity extends downward and backward into the pelvis, as the pelvic cavity.
The function of the intercostal muscles is to expand and contract the thoracic cavity for the sake of respiration. The shape of the ribs and their articulations with the vertebrae are such that a slight rotation of the neck of each rib will cause the shaft to swing outward and upward or in the reverse direction. The costal cartilages are elastic enough to permit this movement, and at the same time are strong enough to make the thorax an effective skeletal apparatus. Ninety joints are called into play in the movements of the thorax (24 between the heads of the ribs and the vertebrte, 20 between the tuberosities and the transverse processes of the vertebras, 24 between the ribs and costal cartilages, 14 between the costal cartilages and the sternum, 6 between the costal cartilages and 2 intrasternal). When the shafts of ribs are swung outward and upward the thorax is enlarged in the antero-posterior and transverse axes. In the adult when standing the sternum may be raised nearly 3 cm., and protruded 1 cm. The cartilages of the lower ribs may be raised 4 to 5 cm. The side of the thorax at the level of the second rib may be protruded 3 cm., and at the level of the eighth rib nearly as far. This extent of movement, however, is found only in forced respiration. In ordinary quiet respiration it is far less, the sternum being raised merely 3 or 4 mm. and protruded 2 mm., and the thorax is enlarged at the side merely 5 mm. (R. Fick). The chief muscles used in quiet inspiration are the external intercostals and the intercartOaginous parts of the internal intercostals.
The ventro-lateral abdominal muscles contract the thoracic cavity by depressing the thorax and by pushing the diaphragm upward. They directly contract the abdominal cavity. Contraction of the abdominal cavity is of aid in defecation and parturition. The abdominal muscles are also of value in flexion, abduction, and rotation of the vertebral column and pelvis.
The thorax, with its intrinsic musculature, is in large part covered by the musculature which extends from the tnmk to the shoulder girdle and arm; dorsally by the trapezius and rhomboids, ventrally by the pectoral muscles, and laterally by the serratus anterior and the latissimus dorsi, as well as by the scapula and the muscles which pass from it to the humerus. The upper extremity on each side is largely supported from the spine by the trapezius, rhomboid and levator scapulae muscles but it none the less exerts some pressure on the thorax and interferes to some extent with respiration. If the girdle and arm are fixed or raised the muscles which pass from them to the thorax are an aid in forced inspiration. Advantage of this is taken when in artificial respiration the arms are raised so as to hft the ribs through traction by the latissimus dorsi, the pectoralis muscles and the subclavius. Some of the muscles of the neck, especially the scalene muscles and the sterno-cleido-mastoid, are Ukewise of value in forced inspiration.
ratus lumborum.
The intrinsic muscles of the thorax and abdomen are derived from the twelve thoracic myotomes and the first one or two lumbar and are innervated by the corresponding nerves, while the musculature of the shoulder girdle and arm which covers the intrinsic muscles of the thorax is of cervical origin an d is innervated by cervical nerves. The diaphragm is likewise of cervical origin and is innervated by the phrenic nerve from the cervical plexus. .,
The intrinsic muscles of the back extend over the thoracic musculature (external intercostals and levators of the ribs, fig. 383) and in turn are in part covered by muscles which extend dorsally from the thoracic region (posterior serrate muscles, fig. 380).
In the external layer the fibre bundles run downward and ventralward. This layer is represented in- the thoracic region by the external intercostal muscles, the levators of the ribs and the posterior serrate muscles. The fibre-bundles of the external intercostals (fig. 385), extend between each pair of ribs but between the costal cartilages are replaced by fibrous tissue, the external intercostal ligaments. The levatores costarum (fig. 383), extend from the transverse process of one vertebra to the rib which articulates with the next vertebra below and in some instances the fibre bundles are continued to the second rib below.
The serratus posterior superior and inferior (fig. 380) , are derivatives of the external oblique which during development wander in part over the intrinsic dorsal musculature. The superior serrate arises from the spines of the last two cervical and first two thoracic vertebrae and is inserted into the second to the fifth ribs. The inferior serrate muscle arises from the spines of the last two thoracic and first two lumbar spines and is inserted into the last four ribs. The fibrebundles of this muscles therefore take a direction opposite to that of the other muscles of the group. The muscles aid in inspiration. In the abdominal region the external layer is represented by the external oblique muscle (fig. 387). This arises by digitations from the last seven ribs and is inserted into the crest of the ilium and by means of a broad flat aponeurosis into the Hnea alba in the midventral fine and into the inguinal Hgament below. The external intercostal, levatores costarum, and posterior serrate muscles are innervated from branches which arise near the tubercles of the ribs. The external oblique muscles are innervated by branches which in large part arise in conjunction with or from the lateral branches of the anterior divisions of the last seven thoracic nerves and frequently also by branches from the ilio-hypogastric.
The middle layer of the lateral thoraco-abdominal musculature is composed of fibre-bundles which run downward and backward obliquely across the fibre-bundles of the external layer. In the thoracic region it is represented by the internal intercostal and subcostal muscles. The internal intercostal (fig. 385) muscles lie between the costal cartilages and between the ribs as far dorsalward as the angles, beyond which they are replaced by membranous tissue and by the subcostal muscles. The latter, instead of extending from one rib to the next rib below, extend to the second or third rib below. They are best developed in the lower part of the thoracic cavity. In the abdominal region the middle layer is represented by the internal oblique muscle (fig. 388) . This arises from the lumbo-dorsal fascia, the crest of the ilium and the inguinal ligament and is inserted into the sheath of the rectus abdominis muscle and into the inferior margins of the ventral extremities of the three lower ribs. The aponeurosis, which helps to form the sheath of the rectus, divides in the upper abdominal region into two layers, one of which passes in front and the other of which passes behind the rectus to be inserted into the linea alba in the mid-ventral line. In the lower third of the ventral abdominal wall both layers pass in front of the rectus. The fibre-bundles which compose the internal obUque muscles do not all follow the usual course of the fibre-bundles of this layer. At the level of the iliac crest they pass nearly transversely across the body and below here they slant downward and forward. Just above the inguinal ligament and medial to its centre the internal oblique muscle is continuous with the thin cremaster muscle (fig. 389), which is prolonged over the spermatic cord and the tunica vaginalis of the testis and epididymis in the male and over the
ligamentum teres in the female. The cremaster muscle is attached laterally to the inguinal ligament, medially to the outer layer of the sheath of the rectus near the insertion of the latter.
The inner layer of the thoraco-abdominal musculature is composed of fibre bundles which take a course transversely across the body. In the thoracic region it is represented by the transversus thoracis (fig. 386) , a slightly developed muscle which arises from the costal cartilages of the third to sixth ribs and is inserted into the lower part of the sternum and into the xiphoid process. In the upper portion of the muscle the fibre-bundles extend obliquely downward and forward instead of transversely. In the abdomen this layer is represented by the transversus abdominis (fig. 390) which arises from the cartilages of the lower seven ribs, from the lumbo-dorsal fascia, the iliac crest and lateral part of the inguinal ligament and is inserted into the linea alba by means of an aponeurosis which lies behind the rectus in the upper two-thirds of the ventral wall of the abdomen and in front in the lower third. It is intimately fused with the aponeurosis of the internal oblique.
The main trunks of the anterior divisions of the last five or six thoracic nerves give rise to branches which supply the muscles both of the middle and inner layers of the lateral thoraco-abdominal musculature. In the abdominal region these trunks run in the main between the two layers. Some muscular branches are usually also supplied from the ilio-hypogastric and ilio-inguinal nerves. In the thoracic region the intercostal nerves run external to the subcostal muscles, through the substance of the costal part of the internal intercostal muscles, and internal to the parts of the internal intercostals which lie between the costal cartilages. Eisler includes the subcostal muscles and that part of the internal intercostals which lies internal to the nerve trunk, with the inner rather than with the middle layer of the thoracic musculature.
The ventral part of the muscular thoraco-abdominal wall is represented by a single muscle on each side, the rectus abdominis muscle, except just above the symphysis pubis where the rudimentary pyramidalis is usually found. The rectus abdominis muscle (fig. 388), is a band-like muscle which arises from the ventral surfaces of the fifth to the seventh costal cartilages and from the xiphoid process and is inserted into the superior ramus of the pubis. It is ensheathed by the aponeuroses of the lateral abdominal musculature described above. The component fibre-bundles run nearly parallel with the mid-sagittal line. Transverse inscriptions partially divide the muscles into segments. It is innervated by the last six or seven thoracic nerves. The pyramidalis (fig. 388) is a small muscle which arises from the superior pubic ramus and is inserted into the linea alba for about a third of the distance to the umbilicus.
The lateral intertransverse muscles of the lumbar region described on p. 417 probably belong to the ventro-lateral musculature of the trunk. The nerves supplying them come from the junction between the posterior and anterior divisions of the spinal nerves.
The inguinal (Poupart's) ligament and the inguinal canal, described in detail below, are of considerable practical interest because of the frequency of hernias in this region. In the quadrupeds the pressure of the weight of the abdominal viscera centres toward the umbilicus while in man it centres toward the ventral part of the line of attachment of the abdominal wall to the pelvis. The lower margin of the aponeurosis of the external oblique muscle is here strengthened to form the inguinal (Poupart's) ligament which extends from the anterior superior iliac spine to the pubic tubercle. Near the latter it is reflected (curves medialward) to the pubic crest forming the triangular lacunar ligament (Gimbernart's). The medial half of the inguinal ligament helps to bound a slit-hke space, inguinal canal through which in the male the spermatic cord passes to the scrotum, and in the female, the round ligament passes to the labium majus. This canal begins on the inner side at the (internal) abdominal ring, which is situated above and medial to the centre of the inguinal ligament. The canal, which is about 4 cm. long, extends medialward and downward to the subcutaneous (external abdominal) ring, a slit-like opening in the aponeurosis of the external oblique just above the inguinal ligament. The canal is bounded ventrally by the aponeurosis of the ex-
FASGIM 425
ternal oblique and the cremaster muscle, below by the reflected portion of the inguinal ligament, dorsally by the transversalis fascia and above by the transversus, internal oblique, and cremaster muscles.
The quadratus lumborum (fig. 406), which extends from the twelfth rib to the ilium and ilio-lumbar ligament, is supplied by direct branches of the lumbar nerves in series with the nerves supplying the musculature of the abdominal wall. It will, therefore, be taken up with the intrinsic thoraco-abdominal muscles. It depresses the thorax and abducts and extends the spine. The psoas- muscle, on on the other hand, which also lies at the back of the abdominal cavity, represents an extension of the intrinsic musculature of the limb to the spinal column (see p. 455).
The diaphragm (fig. 391), a dome-shaped muscle which is attached to the distal margin of the thorax and to the upper lumbar vertebrae, and separates the thoracic and abdominal cavities, arises in the embryo in the region of the neck, and maintains cervical relations through its innervation by the phrenic nerves, which spring one on each side usually from the third to fifth cervical nerves. It does not belong morphologically with the other muscles considered in this section, but is here included because of its physiological and anatomical relations and the convenience of treating it in connection with the intrinsic thoraco-abdominal muscles. A diaphragm completely separating the thoracic from the abdominal cavities is found only in the mammals. The central portion of the diaphragm is an aponeurosis or central tendon with a convex ventral and concave dorsal margin. Into this tendon is inserted the musculature which arises on each side from the xiphoid cartilage, the cartilages and tips of the last six or seven ribs and by means of three crura from the sides of the first four lumbar vertebras.
In fishes and tailed amphibians the musculature of the body wall is composed of metamerically segmented musculature. In all higher vertebrates it is hkewise at an early embryonic stage segmental, being composed of the ventro-lateral portions of the myotomes. The ventral ends of the myotomes give rise to a ventral longitudinal muscle which runs on each side of the body next the mid-hne in front, and retains more or less of the primitive segmentation. The rectus abdominis and the infrahyoid muscles represent this system in man. Very frequently traces of the system may also be seen on the upper thoracic wall in the form of slerider muscular and aponeurotic slips. The rectus muscle in man is usually developed from the last seven thoracic myotomes. The pyramidalis becomes spht ofT from its lower end. The lateral part of the ventro-lateral portions of the thoracic myotomes usually gives rise to several strata of muscles which vary somewhat in different vertebrates, although quite similar among the mammals. In man the twelve thoracic and first two lumbar myotomes give rise to the lateral musculature of the thoraco-abdominal wall.
The quadratus lumborum represents the ventro-lateral portions of the lumbar myotomes with the exception of that portion of the first two which enter into the lateral abdominal musculature and of the fifth, which probably undergoes retrograde metamorphosis.
It will be noted that the abdominal wall is composed of musculature which has an origin chiefly from the thoracic myotomes. At an early stage of embryonic development both the thoracic and the abdominal viscera are covered by a non-muscular membrane. The myotomes extend into this from the thoracic region, and as the musculature is differentiated, it approaches the median fine in front and extends distally to the pelvis. Owing to the rotation of the limbs the abdominal musculature is stretched ventrally over an area corresponding to the lumbar and sacra! regions dorsally. The last part of the thoraco-abdominal wall to be furnished with musculature is that about the umbilicus. Occasionally the process fails to be completed in this region.
Each spinal nerve suppUes primarily the musculature derived from the myotome which lay caudal to it, and at first the musculature lies wholly superficial to the nerves. With subsequent differentiation the metamerism is somewhat obscured by anastomosis of nerves and fusion of myotomes; and a part of the internal oblique layer and all the transverse layer of the lateral musculature comes to he on the inner side of the main nerve-trunks.
lowed in the sections shown in figs. 357, 384, and 407.
Tela subcutanea. — As mentioned above, most of the intrinsic thoracic musculature is covered by other muscles, while the superficial layer of the abdominal musculature is subcutaneous. A panniculus adiposus, Camper's fascia, in which much fat may be deposited is usualh' easily distinguishable, especially in the lower part of the ventral wall of the abdomen, from a membranous fascial sheet which is loosely attached to the underlying fascial envelopment of the muscles. To this membrane has been applied the term Scarpa's fascia. Near the groin it is separated from the panniculus adiposus by blood-vessels and lymphatic glands. It is closely bound to the linea alba between the two rectus muscles, to the fibrous structures in front of the pubic bone, to the fascia lata below the inguinal ligament, and to the crest of the ihum.
continued.
Muscle fascias and sheaths. — The posterior serrate muscles (fig. 380) are enveloped by two adherent layers of an aponeurotic sheet that extends as a single membrane between them and is attached lateralward to the ribs and medialward to the spines of the thoracic vertebrae. The membrane between the muscles may represent the rudiment of a primitive continuous muscle such as is found in some lower vertebrates. This membrane may usually be easily separated from the aponeurosis of the latissimus dorsi on its superficial surface and the lumbo-dorsal fascia beneath.
The intercostal muscles are covered by delicate, adherent membranes on each surface. The e.xternal intercostal muscles are continued as aponeurotic bands between thCjCostal cartilages. These serve here as fasciae for the internal intercostals.
The external obhque muscle is covered externally by a dense, adherent membrane and internally by a more delicate membrane except where the muscle is attached to the ribs or fused with the external intercostal muscles. VentraUy and distally these membrau'es are fused beyond the fleshy portion of the muscle to the broad aponeurosis that serves to ensheath the rectus muscle and cover the lower part of the abdominal wall (fig. 389). Dorsally i,he membranes are in part attached to the ribs and in part are fused to form a membrane whioh becomes adherent to the deep surface of the latissimus dorsi in the thoracic region and to th(3 lumbo-dorsal fascia in the lumbar region.
The internal oblique muscle and the transversus abdominis have similar membranous coverings which are fused to the aponeuroses of origin and insertion of these njusoles. The membranes on the muscles are, however, much more delicate than that of the extt;rnal obhque. More or less fusion between the two muscles with disappearance of the membrfj,nes covering the opposing surfaces takes place, especially in the lower part of the abdominal wall. The superficial muscle fasciae of the external oblique and the fasciae of the internal oblique iire continued into the thin cremasteric fascia which covers the cremasteric muscle, spermatic corci and testis.
The transversalis fascia is a thin membrane which lies external to the peritoneum of the abdominal wall. It covers the peritoneal surface of the transversus muscle and its aponeurosis. Ventrally it is continued across the median line internal to the rectus abdominis. In the lumbar region the fascia divides at the lateral margin of the quadratus lumborum (fig. 384), one lamina of it passing dorsal to this muscle to be attached to the lumbo-dorsal fascia. The other lamina extends over the ventral surface of the quadratus and becomes fused with the psoas fascia. Proximally the transversalis fascia becomes fused with the fascial mernbrane adherent
to the diaphragm. In the region of the ihac fossa the transversalis fascia is reflected from the transversus muscle to the ilio-psoas fascia, with which it usually becomes fused. Sometimes, however, it may be traced as a very delicate membrane over the iliac artery and vein. As these vessels pass below the inguinal ligament a process from the transversalis fascia is usually reflected into their sheath.
The sheath of the rectus (figs. 384, 407) is formed externally in the upper portion of its extent by the aponeurosis of the external oblique which fuses distal to the costal margin with the external layer of the aponeurosis of the internal oblique. In the lower portion of the abdomen this fusion takes place nearer the linea alba than in the upper portion. In the lewer third of its extent the rectus is covered ventrally by the fused aponeuroses of the two oblique muscles conjoined with that of the transversus. Internally the rectus is covered in the upper two-thirds of the abdomen by the inner layer of the aponeurosis of the internal oblique conjoined with that of the transversus and by the transversalis fascia. In the lower thkd of the abdomen the aponeurosis of the internal obhque, together with that of the transversus, passes in front of the rectus, leaving the rectus in this portion of its abdominal surface covered merely by the transversahs fascia and the peritoneum. The line which marks the lower limit of the dorsal ensheathment of the rectus by the aponeurosis of the transversus muscle is called the linea semicircularis,
it is sometimes separated by a distinct fascial layer.
Between the rectus muscles of each side the investing aponeuroses are firmly united into a dense tendinous band, the linea alba (fig. 389). This is broadest opposite the umbilicus. Above this it gradually grows narrower toward the xiphoid process to the ventral surface of which it is attached. From the tip of the xiphoid process it is often separated by a bursa. Toward the symphysis pubis it extends as a narrow line. Just above the symphysis it divides to be attached on each side to the tubercle (spine) of the pubis. Behind it broadens into the adminiculum linem alboe which is attached on each side to the pubis. The linea alba is composed mainly of the interlacing of the fibres which pass into it from the aponeurotic sheaths of the rectus abdominis. From it and Scarpa's fascia, a few centimetres above the symphysis, there arises a broad elastic band, the fundiform ligament (superficial suspensory ligament) of the penis, which sends a fasciculus on each side of the penis. At the umbilicus there is a circular opening encircled by dense fibrous tissue and filled with a thick connective tissue, extending from the tela subcutanea to the subserosa.
The ventral layer of the lumbo-dorsal fascia and its relations to the abdominal muscles also merit attention. This lies between the intrinsic dorsal musculature and the quadratus lumborum muscle and extends from the twelfth rib to the ilio-lumbar ligament. It is strengthened by the lumbo-costal ligament, which extends between the transverse processes of the first and
second lumbar vertebras and the twelfth rib, and by fibrous processes which extend into it from the transverse processes of the lumbar vertebras to which it is attached. With the lateral margin of this ventral layer the dorsal layer of the lumbo-dorsal fascia is fused. The dorsal aponeurosis of the transversus muscle is united to the lumbo-dorsal fascia at the line of junction of the ventral and dorsal layers. The internal oblique muscle, covered externally by a fascia continued dorsally from the external obhque, arises in part from the dorsal layer of the lumbo-dorsal fascia near the junction of the two layers.
The inguinal ligament (Poupart's ligament) (figs. 387, 389, 390) is a strong band which extends along the distal margin of the aponeurosis of the external oblique from the anterior superior iliac spine to the pubic tubercle. Internally the iliac fascia is fused to it. Distally the fascia lata of the thigh is attached to it. The deeper lateral abdominal muscles m part
Falx inguinalis
arise from it. Medially near the attachment of the hgament to the pubic tubercle (spine) diverging fibres are given otT which pass inward and upward to the pecten (crest) of the pubis and give rise to the triangular lacunar ligament (Gimbernat's ligament). This is fused with the fascia of the peotineus muscle and bounds the femoral ring. Above the inguinal ligament near its medial extremity lies the external opening of the inguinal canal, the subcutaneous (external)
inguinal ring [annulus inguinalis subcutaneus]. This opening is formed by the diverging of the lower medial fibres which compose the aponeuroiss of the external oblique muscle. The superior fibres form the upper boundary, superior crus, of the ring and pass to the front of the symphysis pubis. The inferior fibres form the inferior boundary, inferior crus, of the ring and pass to the pubic tubercle (spine). Between these two fibre bands intercrural (intercolumnar) fibres arch about the lateral boundary of the ring and serve to strengthen the anterior and inferior walls of the inguinal canal. Some of the fibres of the superior crus, intermingled with other fibres cross to the opposite side of the body and are inserted into the tubercle (spine) and crest of the pubis and into the superior crus of the opposite side. The structure thus formed is called the reflected inguinal ligament (CoUes's ligament, or triangular fascia).
Inguinal canal [canalis inguinalis]. — This term is apphed to the slit in the lower margin of the abdominal wall through which, in the male, the spermatic cord passes, and in the female, the hgamentum teres. It is not a true canal. The inner end begins at the (internal) abdominal ring [annulus inguinalis abdominahs]. This is situated just above and slightly medial to the middle of the inguinal (Poupart's) ligament. Below the hgament in this region lies the femoral canal through which the femoral vessels pass into the thigh. The (internal) abdominal ring is covered by the peritoneum and the transversalis fascia. The latter here sends a shallow funnel-like extension outward to be attached to the spermatic cord. The base of this funnelHke depression toward the inguinal (Poupart's) ligament is formed by a thickened band of tissue, the tractus ilio-pubicus. Medially and laterally the bundles of fibrous tissue which constitute this tract spread out fan-like, medially over the sheath of the rectus and toward the pubis, lateraUy over the transversus muscle and toward the crest of the ilium. The transverse abdominal muscle arises from the inguinal ligament nearly as far as the lateral margin of the abdominal ring. The fibre-bundles of this portion of the muscle course ventralward above the base of the funnel mentioned above and are inserted by tendons forming a more or less complete aponeurosis, the "conjoined tendon" [falx inguinalis], common to it and the internal obhque into the ventral sheath of the rectus abdominis muscle, into the tubercle, crest and pecten of the pubis and sometimes into the pectineal fascia or the lacunar (Gimbernat's) ligament. Tendinous bands from the transversahs muscle curve downward medial to the (internal) abdominal ring and help to strengthen the transversalis fascia here. These bands constitute the interfoveolar ligament [ligamentum interfoveolare, Hesselbachij. The fibrous bands constituting this ligament are attached to the lacunar ligament and the pectineal fascia.
From the internal ring the spermatic cord (or in the female the hgamentum teres) passes downward and forward in a space (inguinal canal) about 4 cm. long and then through the subcutaneous (external abdominal) ring which has been described in connection with the inguinal ligament. The ventral wall of the inguinal canal is composed of the aponeurosis of the external oblique, the intercrural fibres, and the cremaster muscle. Laterally it is also covered by the caudal portions of the internal oblique and transversus muscles. The caudal wall or floor of the space is formed chiefly by the lacunar (Gimbernat's) hgament and laterally also by the ihopubic tract. Cranialward the lateral part of the space is covered by the transversus and internal oblique muscles, the medial part by the cremaster muscle. The dorsal (internal) wall is formed mainly by the transversalis fascia. IMedially the lacunar (Gimbernat's) ligament and the conjoined tendon (falx inguinahs), when this is well developed, help to form the dorsal wall. Lateral to these structures the dorsal wall is thinner but may be strengthened by a well developed ilio-pubic tract. Near the (internal) abdominal ring it is strengthened by the interfoveolar ligament, and sometimes by muscle slips (interfoveolar muscle).
Abdominal fossae in the inguinal region. — The hernias so frequent in this region make a special study of the inner surface of the abdominal wall of considerable practical importance. Medial to the abdominal (internal) inguinal ring the inferior internal epigastric vessels give rise to a shght fold (plica epigasirica) which slants medialward and upward toward the rectus muscle. From the lateral margin of the tendon of insertion of the rectus muscle upward toward the umbilicus over the obliterated umbilical artery there extends a better marked fold, the plica umbilicalis lateralis. Lateral to the plica epigastrica lies the fovea inguinalis lateralis, with the internal inguinal ring. Between the phca epigastrica and the phca umbihcalis laterahs lies the fovea inguinalis medialis. In the latter region the fascia transversalis which here forms the inner wall of the inguinal canal is strengthened by two longitudinal fibrous bands belonging to the aponeurosis of the transversalis muscle and described above, the hgament interfoveolare at the medial side of the (internal) abdominal ring, and the falx inguinalis (conjoined tendon) lateral to the rectus muscle. These bands vary in width. When they are narrow the part of the internal wall of the inguinal canal covered merely by the thin transversalis fascia and the peritoneum is relatively large and, since this region hes behind the subcutaneous (external abdominal) ring, opportunity is offered for direct inguinal hernia.
Structure. — The muscle is long, flat, and somewhat triangular in form. Cranialward it is broad and thin; caudalward it becomes thicker as it converges toward the insertion. The fibre-bundles of the muscle have a longitudinal course. It is crossed by several incomplete, zigzag, transverse tendinous bands, inscriptiones tendinese, better developed on the ventral than on the dorsal surface of the muscle and intimately united to the ventral sheath of the rectus. One of these, corresponding segmentally to the tenth rib, is usually situated opposite the um-
bilicus. Another, corresponding to the ninth rib, is situated midway between this and the lower margin of the thoracic wall, and one corresponding to the seventh rib is found at the level of the xiphoid process. Between this and the one corresponding to the ninth rib an additional inscription is frequently found. Below the umbilicus an inscription corresponding with the eleventh rib is often found (30 per cent.). In these inscriptions many of the fibre-bundles have their origin and insertion. The thoracic attachments take place by means of band-like fascicuU which extend upward from the highest inscription, the fibre-bundles of these fasciculi being inserted by short tendinous bands. The pubic attachment of the muscle takes place by a* short, thick tendon, usually divisible into two portions, of which the broader, lateral portion is inserted into a rough area extending from the pubic tubercle (spine) to the symphysis, while the more slender medial portion is attached to the fascise in front of the symphysis pubis, where its fibres interdigitate with those of the opposite side. In addition to the attachments mentioned, some of the fibre-bundles are attached to the sheath of the rectus and many, after interdigitating, terminate in the intramuscular framework.
Nerve-supply. — The anterior branches of the six or seven lowermost intercostal nerves enter the deep surface of the muscle neai^its lateral edge. The cutaneous branches pass obliquely through its substance, while the muscular branches give rise to an intramuscular plexus. As a rule, the chief ventral branch of the tenth thoracic nerve enters the substance of the muscle slightly below the umbilical transverse inscription. The branches of the eleventh and twelfth nerves enter at a lower level. The main branch of the ninth nerve enters slightly below the preumbilical inscription; the eighth nerve, between this and the lower margin of the thorax. Either the sixth or seventh nerve may supply the fascicuh of origin. In addition to the main branches other smaller branches of the nerves of the abdominal wall are also usually distributed to the muscle. Each segment, either directly or through intramuscular plexuses, has a supply from more than one spinal nerve.
runs on its deep surface.
Variations. — The rectus muscle varies in the number of its tendinous inscriptions and in the extent of its thoracic attachment. It may extend farther than usual on the thorax. Frequently aponeurotic slips or slips of muscle on the upper part of the thorax indicate a more primitive condition in which the muscle extended to the neck. Absence of a part or the whole of the muscle has been noted. The muscles of the two sides may be separated by a considerable interval in the neighbourhood of the umbiUcus. The muscle is relatively thicker in men than in women..
alba for about a third of the distance to the umbilicus, and give rise to a flat, triangular belly.
Nerve-supply. — Usually through a branch of the twelfth thoracic, which may extend into the muscle through the rectus abdominis. Not infrequently a special branch extends into the muscle from the iho-hypogastric or ilio-inguinal or, rarely, from the genito-femoral.
Variations. — It is missing in about 16 per cent, of instances (Le Double). Dwight has found it absent in 81 out of 450 males and in 60 out of 223 females dissected at the Harvard Medical School. It may extend upward to the umbilicus or be but very shghtly developed. It may be double. In many of the mammals it is missing. It is well developed in the marsupials and monotremes.
Structure and insertion. — The fibre-bundles take a nearly parallel course downward and lateralward and give rise to a flat belly which ends by four fasciculi on the upper margin of the second to the fifth ribs, lateral to the ilio-costahs.
Neroe-supply. — Through branches from the first four intercostal nerves. These nerves give rise to a plexus which passes across the deep surface of the muscle in the middle third between the tendons of origin and insertion.
the thorax.
Relations. — It lies upon the wall of the thorax and the intrinsic dorsal musculature and beneath the levator scapulae, rhomboids, serratus anterior, and trapezius. Its fascicuh extend on the ribs to those of the serratus anterior (magnus).
aponeuroses.
Variations. — The fasciculi of both muscles vary in number and may be replaced by aponeurotic slips. Aberrant muscle fasciculi, supracostales posteriores, may be found in the fascia which connects the two muscles. In several of the lower mammals the two muscles are normally continuous.
The intercostales extern! (fig. 385). — These muscles extend in the intercostal spaces from the tubercles of the ribs to the costal cartilagess. The intermediate muscles do not, however, often quite reach the cartilages. The first intercostal muscle may extend to the sternum. The others are continued through the intercostal region by thin aponeuroses, the external intercostal ligaments, the fibres of which have a direction corresponding to that of the muscle fibrebundles. Dorsally the muscles are fused with the levatores, and ventrally the lower seven muscles are more or less fused with the corresponding fasciculi of the external oblique.
Structure and insertion. — The fibre-bundles take a parallel course obliquely forward and downward to the upper margin of the next rib. The proximal fibre-bundles are more obhque than the distal, and the muscles are best developed in the dorsal part of the intercostal spaces.
Relations. — They are covered externally by the pectoral muscles, the serratus anterior, and serrati posteriores, the levatores costarum, the sacro-spinalis (erector spinae), and the external obhque muscles. Internally they are separated by a slight amount of loose tissue from the internal intercostals, the membranes which continue these muscles medially, and from the subcostal muscles.
Variations. — When the twelfth''rib is very small or is lacking, the eleventh intercostal muscle may be missing. When there is a supernumerary cervical or thirteenth thoracic rib, there may be an extra external intercostal muscle. Next to the first intercostal, the fourth most frequently reaches the sternum.
The levatores costarum (fig. 383). — These consist of a series of flat, triangular muscles, each of which arises from the tip and inferior margin of a transverse process and extends laterally with diverging fibre-bundles to be inserted into the dorsal surface of the rib below, from the tubercle to the angle. The fb'st extends from the transverse process of the seventh cervical vertebra to the first rib. They increase successively in size from this to the last, which is attached to the twelfth rib. Those arising from the transverse processes of the eighth to the eleventh thoracic vertebrse send their more medial fibre-bundles across the rib below to join the lateral margin of the succeeding muscle (levatores longi). The levatores costarum are closely united to the external intercostals and are innervated by the 'ntercostal nerves which pass forward in the corresponding intercostal spaces. The first muscle is innervated by the eighth cervical nerve.
developed, the series of levators forms a serrate muscle.
■ The obliquus abdominis externus (fig. 387). — Origin. — By eight fleshy digitations from the external surface of the lower eight ribs immediately lateral to where they join the cartilages. The fu'st five slips interdigitate with the serratus anterior (magnus), the last three with the latissimus dorsi.
Insertion. — (1) By a strong aponeurosis which extends over the rectus to the hnea alba, where the more superficial fibres interdigitate across the median line, and to the inguinal (Poupart's) ligament; and (2) directly into the outer hp of the crest of the ilium. The aponeurosis over the rectus is usually partly fused with the aponeurosis of the internal obhque.
Structure. — The fibre-bundles which compose the flat fasciculi of origin diverge shghtly as they pass forward and downward, and by fusion of their edges give rise to a flat sheet of muscle. The fasciculus taking origin from the fifth rib passes nearly directly ventrally, but the succeeding fasciculi incline somewhat downward, those from the seventh to the ninth ribs showing the greatest downward inclination. The lower margin of the fasciculus which arises from the seventh rib terminates opposite the umbilicus, that from the ninth rib extends toward the anterior superior spine of the ilium, and those from the last three ribs descend to the ihac crest. The first two fasciculi extend over the lateral margin of the rectus, the next two to its lateral edge. The fourth and fifth usually terminate along a line extending ventrally from the anterior superior iliac spine toward the rectus.
Nerve-supply. — The external oblique is supplied by rami from the lateral branches of the lower seven intercostal nerves and usually from the ilio-hypogastric as well. The rami of the first two or three nerves usually extend on the external surface of the muscle, while the others extend on the deep surface of the muscle as the cutaneous branches are passing through it toward the skin. The nerves of the external oblique take a more transverse direction than the fasciculi of the muscle. Thus the branch from the tenth intercostal nerve extends toward the umbilicus and that of the twelfth toward a point midway between the umbilicus and the symphysis pubis. The nerves have a segmental distribution corresponding with the primitive segmental condition of the muscle.
Variations. — It may have a more or less extensive origin from the ribs. Broad fasciculi not infrequently are separated by loose tissue from the main belly of the muscle either on its deep or superficial surface. Occasionally tendinous inscriptions are found. These transverse inscriptions are constant in many of the smaller mammals. The supracostalis anterior is a rare fasciculus sometimes found on the upper portion of the thoracic wall. It is usually suppUed by branches of the upper thoracic nerves and seems to be a continuation upward of the external oblique muscle. In some prosimians the external oblique extends normally to the first or second rib.
3. Internal Oblique Group
The intercostales interni (figs. 385, 386, 388). — These extend in the intercostal spaces from the angles of the ribs to the sternal ends of the spaces. The upper and lower muscles are usually continued dorsally slightly beyond the angles of the ribs, while the intermediate muscles frequently do not quite reach them. Dorso-medially the internal intercostals are continued in
internal lip.
Structure and insertion. — The fibre-bundles take a parallel course downward and dorsalward to the upper margin of the rib below. They are less obliquely placed than those of the external intercostals. The muscles are thicker in front and grow thinner dorsaUy. They contain less fibrous tissue than the e.xternal intercostals.
Relations. Between the internal and external muscles there is some loose areolar tissue. Proximally, for a short distance, the intercostal nerve in each interspace runs between the external and internal intercostal muscles, but more distally it runs first in the substance of and then on the internal surface of the internal intercostal. Eisler distinguishes that portion of the internal intercostal muscle which lies external to the nerve as the intercostalis intermedius, that which lies internal as the true internal intercostal. The terminal branches of the fii'st six nerves, however, pass through the muscle on their way to the skin, while the last six pass beneath the inferior margin of the thorax. Internal to the internal intercostal muscles lie the transversus (triangularis sterni) and sub-
The subcostales (fig. 385). — These muscles are due to an extension over two or more intercostal spaces of those fibre-bundles of the internal intercostal muscles which lie in the proximal part of the interspaces. They arise near the angles of the ribs, and are usually well developed only in the lower part of the thorax. The component fibre-bundles keep the general direction of the internal intercostals, but they converge toward the tendons of insertion, which are attached in each case to the second or third rib below, between the angle and the neck.
Structure and insertion. — From the origin the fibre-bundles radiate forward in a flat sheet. The most dorsal extend to the lower three ribs, where they become continuous with the internal intercostals. The rest extend toward the lateral margin of the rectus, the upper ones toward the xiphoid process, the intermediate toward the umbilicus, the lower ones somewhat obhquely downward across the lower part of the abdomen. The fibre-bundles which extend toward the rectus terminate in an aponeurosis which in its upper two-thirds divides into two layers, one of which passes in front of and the other behind the rectus muscle to the linea alba. In the lower third the aponeurosis passes as a single membrane in front of the rectus. In the neighbourhood of the subcutaneous inguinal (external abdominal) ring the muscle is continued into the cremaster. Medial to the ring some fasciouh are attached to the tubercle of the pubis and to the symphysis.
Relations. — It hes between the external obhque and the transversus. The trigonum lumbale (triangle of Petit) is an area, variable in size, between the posterior margin of the external obUque, the lateral margin of the latissimus dorsi, and the crest of the ihum. In this area the internal obhque is subcutaneous.
Variations. — The attachments and the extent of development of the fleshy part of the muscle vary considerably. Occasionally tendinous inscriptions are found in the muscle which indicate a primitive segmental condition.
The cremaster (fig. 389). — The cremaster muscle is found well developed only in the male. It represents an extension of the lower border of the internal obhque muscle and possibly also of the transverse over the testis and spermatic cord.
Origin. — (1) Lateral, thick and fleshy, from about the middle of the upper border of the inguinal hgament, and (2) medial, thin and tendinous, from the sheath of the rectus muscle and the tubercle (spine) of the pubis.
Structure. — The lateral head is apphed to the lateral side, the medial head to the medial side, of the spermatic cord. Both pass with this through the subcutaneous (external abdominal) ring of the inguinal canal and become spread in loops over the testis. Ensheathing the muscle and between the somewhat scattered fibre-bundles which compose it, there extends a thin, membranous layer of connective tissue, the cremasteric (Cowper's) fascia.
the dartos, and the skin. It covers the spermatic cord and the testis.
Variations. — In the female the muscle is represented by a few fasciculi on the round hgament. It may arise whoUy from the transversalis fascia or be somewhat fused with the transversus muscle. The latter condition is espeoiaUy frequent in muscular individuals.
from the dorsal surface of the lower half of the body of the sternum and the xiphoid process.
Structure and insertion. — The muscle is composed of several flat, thin fasciculi, partly fibrous, more or less isolated, which are inserted by aponeurotic bands into the dorsal surface of the cartilages of the second or third to the sixth ribs, and occasionally also into the tips of the bony portions of the ribs. The lower fasciculus is closely related to the cranial margin of the transversus abdominis.
Nerve-supply. — By rami from the ventral portions of the second to the sixth intercostal nerves. These nerves give rise to a longitudinal plexus across the deep surface of the muscle near the middle of the constituent fasciculi.
mammary vessels lie in front and the pleura and pericardium behind the muscle.
Variations. — It is an exceedingly variable muscle, both in the extent of its attachments and in the development of the individual fasciouh. The fasciculi vary in number from one to six. With this muscle Eisler would class the subcostal muscles and those portions of the internal intercostal muscles which lie internal to the intercostal nerves.
The transversus abdominis (figs. 386, 390). — Origin. — Directly from — (1) the inner side of the cartilages of the lower six ribs by dentations which interdigitate with the attachments of the diaphragm; (2) the internal lip of the iliac crest and lateral half of the inguinal ligament; and (3) through an aponeurosis from the lumbo-dorsal fascia.
Structure and insertion. — The fibre-bundles give rise to a broad, thin belly and take a nearly transverse course across the inner side of the abdominal wall. The most distal fibres, however, are inclined obliquely toward the pubis. The fleshy portion of the muscle terminates in a strong aponeurosis along a curved line, which extends above well under the rectus and emerges
Serratus anterior
lateral to the rectus opposite the umbilicus, whence it extends toward the middle of the inguinal ligament. In the upper two-thirds of the abdomen the aponeurosis extends behind the rectus to the linea alba and fuses with the inner lamina of that of the internal oblique. In the lower third of the abdomen it extends in front of the rectus to the hnea alba, and is here also fused with the aponeurosis of the internal obhque. Some of the fibres are continued into the aponeurosis of the muscle of the opposite side. The lower attachment of the muscle is somewhat more complex. The fibre-bundles here bend around the spermatic cord, on the medial side of which they are spread out to be attached to the lacunar (Gimbernat's) ligament and pectineal fascia, the pubis, and the sheath of the rectus. The attachment to the lacunar ligament and pectineal fascia takes place by means of an aponeurotic band, the more lateral fibres of which are dense and curve below the spermatic cord to the lacunar hgament and the pectineal fascia below this. This band is caOed the interfoveolar ligament. It is composed partly of bundles of fibres prolonged from the aponeurosis of the opposite transversus, and bounds the abdominal ring medially and below. Medially the transversus is united to the upper part of the os pubis, and to the sheath of the rectus by an aponeurotic band, the falx inguinalis (conjoined tendon). Between the interfoveolar ligament and the falx inguinalis the transversalis fascia forms the posterior wall of the inguinal canal. In this area a detached band of muscle-fibres is sometimes found. This is called the musciilus interfoveolaris.
and is covered on the deep surface by the transversalis fascia.
Variations. — It is very rarely absent. It shows considerable variation in the extent of its development. The pubo-peritonealis is a similar muscle which may pass from the pubic crest to the transversus near the umbilicus. The pubo-transversalis is a small muscle which may extend from the superior ramus of the pubis to the transversalis fascia near the abdominal inguinal ring. The tensor laminae posterioris vaginae musculi recti abdominis, essentially like the preceding, may e.xtend from the inguinal ligament to the rectus sheath on the deep surface of the rectus muscle near the umbilicus. The tensor laminae posterioris vaginae musculi recti et fasciae transversalis abdominis likewise extends from the transversalis fascia near the abdominal inguinal ring to the fold of Douglas.
C. LuMBAE Muscle
The quadratus lumborum (fig. 406). — Origin. — From — (1) the internallip of the iliac crest near the junction of the middle and dorsal thirds, and the iliolumbar ligament; (2) the transverse processes of the three or four lower lumbar vertebra; and (3) the lumbo-dorsal fascia.
vertebra
Structure and insertion. — From the origins there arises a complex quadrangular muscle belly from which spring the fasiouli of termination. These extend to — (1) the transverse processes of the upper three or four lumbar vertebrae; (2) to the fibre-bands which extend out laterally in the lumbar fascia from the transverse processes; and (3) to the medial part of the lower border of the twelfth rib.
and fix the twelfth rib.
Relations. — It rests posteriorly on the lumbo-dorsal fascia and the transverse processes of the lumbar vertebrae. Its medial edge is partly covered by the psoas. In front of it also he the kidney, the intestines, and the lumbar arteries and nerves. It is ensheathed by membranes continued over each surface from the transversalis fascia. Of these, the anterior is the better marked and is called the lumbar fascia.
The diaphragm (figs. 386, 391). — This dome-shaped musculo-membranous sheet has, when seen from above, something of the outline of a kidney. It consists of a pair of muscles which arise one on each side from the thoracic wall and are inserted into a central tendon. Lateral
to the tendon the diaphragm projects higher into the thoracic cavity than in the central area. On the right, in moderate expiration, it extends in adults to the height of the medial extremity of the fifth rib, and on the left to the fifth interspace.
Origin. — On each side from — (1) the lower border' and back of the .xiphoid process and the adjacent aponeurosis of the transversus abdominis or from the tendinous arch extending from the tip of the xiphoid process to the cartilages of the fifth and sixth ribs, {sternal portion) ; (2) the lower border and inner surfaces of the cartilages of the seventh and eighth ribs, the cartilages and osseous extremity of the ninth rib and the osseous extremities of the last three ribs [costal portion); and (3) from the lumbar vertebrae (lumbar portion). The lumbar portion is divided somewhat irregularly into three crura, between which pass blood-vessels and nerves.
The lateral crus arises from the lateral surface of the bodies of the first two lumbar vertebrae and from fibrous thickenings of the fascia over the psoas and quadratus lumborum muscles. Of these, one, the medial lumbo-costal arch (internal arcuate Ugament), extends from the body of the second lumbar vertebra to the transverse process of the same vertebra; the other, the lateral lumbo-costal arch (external arcuate hgament), extends from the tip of the transverse
Coccyx
process of the second lumbar vertebra to the twelfth rib. The lateral crus is only inconstantly attached to this. The intermediate crus arises from the ventro-lateral surface of the body of the second lumbar vertebra from the sides of the bodies of the first two lumbar vertebrae and from the intervening discs. The medial crus arises from the front of the bodies of the third and the fourth lumbar vertebrae. On the left side it usually extends only to the third vertebra, and it does not always extend to the fourth on the right. The extremity and medial margin of this crus are tendinous, the lateral portion fleshy. On the second, third, and fourth, and the lower part of the first lumbar vertebrae the medial crus of each side is separated from its fellow by the hiatus aorticus (for the aorta and thoracic duct). Over the first lumbar vertebra they are fused by a process which extends from the right crus into the lower ventral sm'face of the left. Above here the right crus may be divided into two parts, one of which, fused with the left crus, passes on the left of the hiatus oesophageus, while the other passes on the right. Sometimes the hiatus oesophageus lies between the right and left crura. Frequently the left crus gives off a slip which passes to the ventral surface of the right below the hiatus.
The costal portion arises by a series of dentations which do not correspond perfectly in number with the ribs. Some costal cartilages have two dentations attached to them. It interdigitates with the transversus abdominis but in part arises from tendinous arches which bridge the origin of the transversus in the last three interspaces.
the place of the stem being taken by the region occupied by the vertebral column, one leaflet lying on each side of this and one in front. The ventral part is usually placed somewhat to the left and is more or less completely fused with the left leaflet. Between the ventral and the right leaflets there is a large opening through which passes the inferior vena cava, the foramen venae cavae. The leaflets are fused in front and behind this.
Fig. 393.— Ventr.4l Coccygeal Muscles (After Eisler.)— 1. M. sacrococcygeus anterior. 2. M. coccygeus. 3. M. piriformis. 4. M. obturator internus' 5. Fascia iUaca, above the iliopsoas. 6. Fibrocartilago intervertebralis lumbosacralis. 7. Ventral trunk of first sacral nerve. 8. Sacral plexus.
The fleshy portion of the muscle is composed of fibre-bundles which pass at first nearly vertically upward and then arch over to be attached to the margins of the central tendon. The sternal portion of the muscle is the shortest. It is often separated from the costal portion by a small space through which the superior epigastric vessels pass.
Nerve-supply. — From the phrenic nerves, one of which arises on each side from the third to the fifth cervical nerves. Each nerve penetrates the diaphragm lateral to the central tendon and breaks up into an extensive plexus on the inferior surface of the muscle. Some of the lower intercostal nerves also contribute to the sensory innervation of the margin of the muscle and possibly also slightly to the motor innervation. The sympathetic nerves furnish fibres for the blood-vessels.
Action. — To enlarge the thoracic cavity and thus cause inspiration. According to R. Fick, however, the diaphragm plays a less important part in inspiration than is usuaUv assumed for it. The middle part of the central tendon is united to the pericardium and through this to the cervical fascia, and is, therefore, not very movable. In the contraction of the muscle it is the dorsal and lateral portions which in the main are flattened. The diaphragm aids in defecation, parturition and vomiting, by the pressure it exerts on the abdominal viscera. It also acts as a constrictor of the oesophagus.
pancreas, spleen, kidneys, and suprarenal bodies.
Variations. — The sternal portion of the muscle is frequently absent. Infrequently the diaphragm is incompletely developed dorsally on the left side. This condition is rarer on the right side. The extent of the various insertions of the diaphragm shows considerable individual differences. The vertebral portion of the muscle may be slightly fused with the psoas or with the quadi-atus lumborum. Some fusion of the ventral portion of the muscle with the transversus
V. MUSCULATURE OF THE PELVIC OUTLET
In order to understand the musculature of the pelvic outlet it is necessary first to consider briefly the structure of the pelvis. It is bounded laterally and in front by the ilium below the terminal (ilio-pectineal) line, the ischium and the pubis, and by the obturator membrane and the sacro-spinous (small sciatic), sacro-tuberous (great sciatic) and the interpubic hgaments. The pubis, ischium and the obturator membrane are covered by the obturator internus muscle (figs. 392, 401) which here takes its origin and which converges toward and passes through the lesser sciatic notch on its way to its insertion on the great trochanter of the femur. The piriformis muscle (figs. 393, 396), which arises from the sides of the pelvic surface of
Sphincter ani
the sacrum, from the posterior border of the great sciatic notch and the neighbouring part of the sacro-tuberous (great sciatic) ligament nearly fills up the great sciatic notch on its way to its insertion on the great trochanter. The walls of the pelvis are thus padded by muscles which belong to the limb. The muscles are covered by fascia best developed over the obturator internus muscle as the obturator fascia. The gluteus maximus muscle (figs. 392, 394, 400, 401), which arises from the back of the ilium, the sacrum, and the coccj^x, and is inserted into the femur and the fascia of the thigh overlaps to some extent the sacro-tuberous ligament, and in the standing position the tuberosity of the ischium so that its lower margin forms an accessory boundar}' to the pelvic outlet.
The outlet of the pelvis thus bounded by bone, ligaments and by muscles belonging to the lower extremity presents two triangles (figs. 392, 394), an anterior or urogenital triangle, with the base between the two ischial tuberosities and the apex below the symphysis pubis, and a posterior or rectal with the base between the ischial tuberosities and the apex at the coccyx which projects into it here. The outlet is closed by a special musculature divisible into three groups of muscles and fascia; those of the pelvic diaphragm and anus, those of the urogenital diaphragm, and those of the external genitalia.
The pelvic diaphragm [diaphragma pelvis] extends from the upper part of the pelvic surface of the pubis and ischium to the rectum which passes through it to be surrounded by the external sphincter. The urogenital trigone or urogenital diaphragm [diaphragma urogenitale] lies between the ischio-pubic rami superficial to the pelvic diaphragm and surrounds the membranous urethra and in the female also the vagina. The external genital muscles lie superficial to the trigone.
ischial spine and is inserted into the lateral margin of the lower sacral and the upper coccygeal vertebrae. It is closely applied to the pelvic surface of the sacrospinous (small sciatic) ligament. In so far as it is active it flexes and abducts the coccyx.
The levator ani arises (figs. 395, 396, 397) from the inner side of the pubis, along a line extending laterally from the inferior margin of the symphysis to the obturator canal, and from the obturator fascia along a line, the arcus tendineus, extending from the pubis to the spine of the ischium. The levator ani is inserted into the median raphe back of the anus, the ano-coccygeal raphe, into the tip and sides of the coccyx and into an aponeurosis, which is attached to the anterior sacrococcygeal ligament. It is divisible into three portions, a pubo-coccygeal, an iliococcygeal, and a pubo-rectal. The levator ani muscles of the two sides are separated by a slit which extends from the rectum to the symphysis pubis and in which in the male lie the lower part of the prostate, and the membranous urethra (fig. 396), and in the female the vagina and urethra (fig. 395). Back of the rectum some of the fibre-bundles from the muscles of the two sides interdigitate, while
others terminate in the ano-coccygeal raphe. A few fibre-bundles also interdigitate across the median line, in front of the rectum (pubo-coccygeal, fig. 395) and some are inserted into the walls of the rectum. The levator ani and coccygeal muscles of the two sides form a funnel-shaped muscular support for the pelvic viscera (fig. 399). When the abdomino-thoracic diaphragm contracts, as during inspiration, the pressure on the viscera is transmitted to the pelvic diaphragm which resists the pressure and elevates the viscera when the abdomino-thoracic diaphragm relaxes. The levator ani muscle also constricts the rectum and pulls it forward and in the female constricts the vagina from side to side.
As it passes through the pelvic diaphragm, the rectum for about two and a half centimetres is surrounded by a special external sphincter muscle ffigs. 393, 394, 397), divisible into three concentric layers as described below. This muscle, especially differentiated from the primitive sphincter of the cloaca,
levator ani
serves to close the rectum. It is supplemented by a sphincter of smooth muscle which lies immediately beneath the mucous membrane of the anus. It is attached behind to the coccygeus, and in front to the central tendon of the perineum described below.
The lateral origin of the levator ani, as above described and as shown in figs. 396 and 399, is considerably above the osseous and muscular margin of the pelvic outlet. The muscles of each side converge toward the post-anal region so that a space is left between the lateral wall of the pelvis, and the levator ani and external sphincter (fig. 399). It is deepened laterally by the lower margin of the gluteus maxim us muscle (fig. 400). In the fascial canal (Alcock's canal) in the lateral wall of the
fossa run the internal pudic vessels and nerves (fig. 401). Above the pelvic diaphragm in the median part of the pelvic cavity are found the bladder, the ampulla of the rectum, and the prostate gland (in the male) or the vagina and uterus (in the female). Laterally on each side there is a subperitoneal space, filled with connective tissue and containing blood-vessels and nerves (fig. 402) . Fasciae invest each surface of the pelvic diaphragm {diaphragmatic fascia) and extend about the viscera [endo-pelvic fascia) .
Sphincter ani externus subcutaneus
The muscular apparatus of the anterior or urogenital triangle of the pelvic outlet is much more complicated than that of the posterior or rectal triangle just described. We have seen that between the levator ani muscles of each side in front of the rectum there is a slit which extends to the symphysis pubis and that through it, the lower part of the prostate and the urethra extend in the male, the urethra and the vagina in the female. Between the ischio-pubic rami there is stretched a triangular muscular and fibrous membrane, which likewise surrounds these urogenital ducts and which serves to strengthen the pelvic wall in this region. This structure is known as the urogenital trigone (figs. 398, 400, 403). The musculature within it, called by Holl the accessorj^ or urogenital diaphragm, includes two muscles (fig. 398), the sphincter urogenitalis (urethraj) and the deep transverse perineal muscle. The sphincter embraces the urethra and associated structures. The component fibre-bundles arise chiefly from the fibrous tissue in the angle beneath the symphysis pubis, but partly also from the descending pubic rami. They pass analward and medialward on each side of the urethra and then partly interdigitate across the median line, partly terminate in a median raphe. Some fibre-bundles embrace in the male the lower part of the prostate and Cowper's gland. In the female the fibre-bundles of the sphincter partly terminate in the wall of the vagina. Some of them are continued downward on each side of the vagina and interdigitate with fibre-bundles from the deep transverse perineal muscle. The deep transverse perineal muscle (fig. 398) arises on each side from the ischio-pubic ramus. It constitutes a flat band of muscle, the fibre-bundles of
median raphe.
The musculature of the urogenital diaphragm is enclosed between two well marked fasciallayers (fig. 400, 403), the deep (superior) and superficial (inferior) layers of the urogenital trigone (triangular ligament). The anterior margins of the two fascial layers are fused to form the transverse ligament of the pelvis which extends between the inferior pubic rami, beneath the dorsal nerves and veins of the penis (clitoris). At the anal margin of the musculature these two layers are also fused with one another. The deep layer of the urogenital trigone forms the floor of the anterior recess of the ischio-rectal fossa (fig. 400).
Superficial to the urogenital trigone lie the external genitalia (figs. 392, 394). Although the musculature in the two sexes is fundamentally similar, neverthel^gs, owing to the differences in the structure of the genitalia in the two sexes, it is convenient to take up first the external genital musculature in the male and then that in the female.
It lies in the groove between the ischio-pubic ramus and the urogenital trigone (fig. 398), to the former of which it is firmly united. It is enwrapped on its free medial surface by the ischio-cavernosus muscle (erector penis) (figs. 398, 402). The fibre-bundles of this muscle arise from the ischial tuberosity and from the ischio-pubic ramus on each side of the attachment of the crus. It is inserted into the medial and ventral surfaces of the crus near the attachment of the suspensory ligament.
The corpus spongiosum [corpus cavernosum urethrae] terminates posteriorly in the bulb which lies on the urogenital trigone between the two crura (figs. 394, 402). It is united to the superficial layer of the trigone (fig. 402). It is enveloped by the bulbo-cavernosus muscle, composed of right and left halves united by a median raphe on the superficial surface of the bulb (fig. 394). Each half consists of several superimposed laj^ers of fibre-bundles described below. It is inserted into a tendinous structure situated in front of the anus, the central tendon of the perineum,
The superficial transverse muscle of the perineum (figs. 392, 394) arises on each side from the ascending ramus of the ischium and is inserted into the central tendon of the perineum. It is frequently weakly developed. It acts with the deep transverse perineal muscle in fixing the perineum and thus offering support for the action of otiier muscles.
In the female (fig. 392) the ischio-cavernosus does not differ markedly from that in the male although usually it is smaller. The superficial transverse muscles are, on the other hand, usually relatively better developed. The central tendon of the perineum is likewise usually better developed in women and is more elastic, a characteristic of value in childbirth.
The chief difference in the musculature in the two sexes is found in the bulbo-cavernosus (fig. 392) . This, in the female, arises from the back of the clitoris, the corpus cavernosum and the trigone. It covers the outer side of the bulb of the vestibule and the gland of Bartholin. It is inserted into the central tendon of the perineum. The chief function of the pair of muscles is to constrict the vagina.
MORPHOLOGICAL REMARKS
While the shoulder-girdle and the muscles which extend from this and from the trunk to the upper extremity are superficially placed with respect to the trunk, and do not interrupt the trunk musculature the reverse is true of the hip-girdle and the musculature of the lower extremity. The hip-girdle is firmly united to the spinal column at the sacrum. The muscles which arise from the trunk and are attached to the lower limbs are few in number compared with those of the upper extremity and, unhke the latter, are deeply placed. Thus the psoas major muscle (fig. 406) arises on each side of the lumbar region of the spinal column at the back of the abdominal cavity and is inserted into the femur and the piriformis (fig. 406) arises from the front of the sacrum at the back of the pelvic cavity and is inserted into the great trochanter of the femur. The skeleton and musculature of the lower extremity, furthermore, markedly interfere with the continuity of the trunk musculature which in the lower vertebrates and in the human embryo may be followed continuously to the caudal end. The interruption is much less marked behind than in front. The intrinsic dorsal spinal musculature extends well down over the back of the sacrum, but on the back of the lower end of the sacrum and on the back of the coccyx there is found merely the inconstant sacro-coccygeus posterior. Of the ventro-lateral musculature the musculature of the abdominal wall, as is indicated by its innervation, is derived from the lower thoracic and the first one or two lumbar myotomes; thequadratus lumborum, at the back of the abdominal cavity (fig. 406), from the first three or four lumbar myo-
tomes. Beyond here there is an interruption until we come to the musculature of the pelvic outlet which, in part, may be looked vipon as modified trunk musculature belonging to the last three sacral myotomes. The intervening region is "cut out" for the reception of the base of the lower extremity.
It is of interest to note that more and more of the ventro-lateral wall of the trunk is "cut out" as the mid-ventral line is approached. Thus while the quadratus lumborum behind represents spinal segments as far caudal as the third or fourth lumbar, the rectus abdominis in front represents segments merely as far caudal as the twelfth thoracic. Similarly while the
the levator ani at the front represents chiefly the fourth.
The musculature which in the tailed mammals is used to move the tail as well as to wall off the pelvic cavity and close rectal and urogenital openings, in man is modified whoUy for the latter functions. It constitutes the pelvic diaphragm.
The tela subcutanea in the male perineal region contains many bundles of smooth muscle fibres continuous with and similar to the dartos of the scrotum (corrugator cutis ani). At the sides where it passes over the lower margin of the gluteus maximus it contains a large amount of fat, but in the dorsal region over the coccyx and sacrum, as in the mid-perineal region, the fat is limited in amount. In the labia majora of the female perineum there is much fat in the tela subcutanea.
The ischio-rectal fossa (figs. 401, 402) is bounded laterally by the obturator internus muscle and fascia, the tuberosity of the ischium and the ischio-pubic ramus, medially by the levator ani and coccygeus muscles and fasoise, ventraUy by the dorsal aspect of the urogenital trigone and dorsaUy by the gluteus maximus muscle. An anterior recess extends forward well toward the body of the pubis between the levator ani, the ischio-pubic ramus and the urogenital trigone. A posterior recess may likewise be traced backward covered by the lower edge of the gluteus maximus (figs. 400, 401). The fossa is filled with loose fatty tissue continuous with that of the tela subcutanea. Through it pass the hemorrhoidal, and long and short perineal branches of the pudic artery and nerve. The main trunks of these vessels and nerves lie in a special fascial compartment (Alcook's canal) in the lateral wall (fig. 401).
The external genital organs are covered by a special deep layer of the tela subcutanea, the superficial perineal (CoUes') fascia (fig. 402). This is attached on each side to the lower margin of the ischio-pubic ramus and to the ischial tuberosity. At the posterior margin of the superficial transverse perineal muscle it fuses with the two fascial layers of the trigone. It is adherent to the central tendon of the perineum and to the raphe of the bulb. Anteriorly it is continuous with the deep layer of the tela subcutanea covering the scrotum, the penis, and the lower part of the abdominal wall. In rupture of the urethra urine is prevented, by the attachments of the tela, from getting further back than the posterior edge of the trigone, but anteriorly it may extend to the surface of the abdomen. Here it may extend upward for a considerable distance, but it is kept from the thighs by the attachment of the deep laj'er of the tela subcutanea (Scarpa's fascia) to the inguinal ligament.
Muscle fasGise. — The muscles of the urogenital diaphragm, the urogenital (urethral) sphincter and the transversus perinei profundus, are contained between two fascia layers which constitute the superficial (inferior) and deep (superior) layers of the urogenital trigone (the superficial or inferior and the deep or superior layers of the triangular ligament).
teriorand posterior recesses
The superficial (inferior) layer (figs. 392, 394, 400, 402, 403) which lies between the external genitalia and the urogenital diaphi-agm, is composed of strong bands of fibrous tissue which extend ■ transversely across the subpubic arch and are attached to a ridge on the ischio-pubic rami. It is separated from the arcuate (subpubic) ligament by a mass of fibrous tissue through which the dorsal veins and nerves of the penis (clitoris) run, and in which there is a venous plexus.
Muscles of thigh
Beneath this tissue a fibrous band, the transverse ligament of the pubis, extends between the descending pubic rami. This represents a region of fusion of the deep and superficial layers of the fascia of the trigone. Posterior to the deep transverse muscle the two layers are likewise fused. The superficial layer is better developed in the front than in the back part of the space. It is pierced by the urethra (about 3 cm. below the symphysis) by the ducts of the bulbo-urethral
In the female it is pierced by the vagina as well as by the structures mentioned above.
Beneath the superficial layer of the fascia of the trigone, in addition to the muscles of the urogenital diaphragm, there are found the membranous uretlira, the bulbo-urethral glands (Cowper's), the internal pudic arteries and the pudic nerves (in part).
The dee-p (superior) layer of the urogenital trigone (figs. 400, 402, 403) lies between the muscles of the urogenital diaphragm and the ischio-rectal fossa and levator ani. It may be looked upon as a continuation of the obturator fascia across the pubic arch. Posterior to the deep transverse perineal muscle it fuses with the superficial layer of the fascia of the urogenital trigone. In this region in the male it fuses with a fascial membrane, the prostaiico-perineal fascia, which extends upward between the rectum and prostate, and is attached to the posterior wall of the latter. In the female it is fused with the fibrous tissue which lies between the vagina and the rectum.
Above, the fascia on each side
is attached to the linea terminalis and is continuous with the fascia transversalis and the iliac fascia. It is attached to the margins of the greater and lesser sciatic notches and to the ischiopubic ramus and the body of the pubis. Between the ischio-pubic rami it is stretched across the subpubic arch and forms the superior or deep layer of the urogenital trigone described above. The portion of parietal pelvic fascia over the obturator internus muscle is called the obturator fascia.
The diaphragmatic pelvic fasciae cover both surfaces of the pelvic diaphragm and are reflected upon the viscera. The fascia; covering the two surfaces of the levator ani are attached to the parietal (obturator) fascia along the line of origin of the muscle.
The line of attachment of the levator ani divides the obturator fascia into two parts (fig. 399), a pelvic part above the line of attachment, covered by peritoneum, and an ischio-rectal part below the line of attachment. The latter bounds the lateral wall of the ischio-rectal fossa. The former part is much the thicker. It consists morphologically of two fused membranes, the obturator fascia proper and the aponeurosis of the ilio-coccygeal portion of the levator ani, which although usually fused with the obturator fascia, may frequentlj' be traced to the terminal (ilio-pectineal) line from which in tailed mammals this portion of the levator takes origin. The two layers of fascia also become continuous at the medial margin of the muscle where this faces the urogenital passage (fig. 399). Posteriorly, the inner layer fuses with the tendinous insertion of the pubo-coocygeus portion of the muscle and the fasciae of the muscles of each side are continuous. It also fuses with a fascia covering the coccygeus muscle.
The thin perineal layer of the levator fascia behind the rectum fuses with that of the opposite side and is attached to the coccyx and the ano-coccygeal raphe. About the anus it helps to form a covering for the external sphincter. Ventrally it is attached to the ischio-pubic rami. It forms the medial wall of the ischio-rectal fossa.
Endo-pelvic fascia (figs. 401, 402), — The peritoneum is reflected from the pelvic wall onto the viscera much higher up than the level at which the viscera are attached to the pelvic diaphragm. Between the pelvic fascia covering the deep surface of the pelvic diaphragm (levator ani and coccygeus muscles) and the peritoneum there is thus left a space, subperitoneal space (fig. 467 B). In the median plane in this region in the male are found the bladder, prostate, seminal vesicles, the ureter and ductus deferens in their course near the bladder, and the ampulla of the rectum. In the female we find here the bladder, the vagina, the uterus, and the ampulla of the rectum. Between these medially placed viscera and the lateral wall of the pelvis
there is an irregularly shaped space, cavum pelvis subperitoneale, bounded above by peritoneum, below by the fascia covering the pelvic diaphragm and filled with connective tissue of varying density. The tissue in this space in the female is continuous with that between the two peritoneal surfaces of the broad ligament. Between the viscera in the subperitoneal region and about their walls tlie connective tissue is more or less definitely condensed into membranes which constitute the endopelvio fascia, variously described by different authors. The fascia covering the pelvic diaphragm, especiaOy that on the deep surface, is fused to the endopelvic fascia where the viscera pass through the pelvic diaphragm. In the connective tissue of the subperitoneal space are found the hypogastric artery and vein and their chief branches, and various visceral nerves. The subperitoneal space above the pelvic diaphragm is to be compared with the subcutaneous space below the pelvic diaphragm known as the ischio-rectal fossa and described above.
A. Muscles of the Pelvic Diaphragm, Coccyx, and Anus
The coccygeus (figs. 393, 396, 397, 400). — Origin. — From the ischial spine and the neighbouring margin of the great sciatic notch. Structure and insertion. — The fibre-bundles diverge to be inserted partly directly, partly by means of an aponeurosis, into the lateral margin of the fourth and fifth sacral vertebrse and of the coccyx. Usually the muscle is composed in considerable part of tendinous connective tissue, especially on the dorsal side of the cranial portion, and the ventral side of the caudal portion.
Nerve-supply. — From the pudendal plexus several small nerves enter the cranial margin and pelvic surface of the muscle. They arise usually from the third and fourth sacral nerves. Action. — Insofar as the muscle is active it flexes and abducts the coccyx. Relations. — Ventrally the muscle bounds the pelvic cavity, from which it is separated by the pelvic fascia, beneath which runs the nerve to the levator ani muscle. The dorsal surface is partly covered by the sacro-spinous (lesser sciatic) ligament and helps to bound the ischiorectal fossa (posterior recess).
doubled. It may be partially fused with the levator ani. Occasionally it is absent.
The sacro-coccygeus anterior (fig. 393). — This inconstant muscle, when well developed, arises from the sides of the fourth and fifth sacral and from the front of the fii'st coccygeal vertebra and from the sacro-spinous ligament. The short fibre-bundles which compose it make up a somewhat irregular beDy which is inserted into the anterior sacro-coccygeal ligament and into the second to fourth coccygeal vertebrse dorsal to the insertion of the levator ani. The innervation is from the fourth and fifth sacral nerves.
The sacrococcygeus posterior is an inconstant muscle consisting of a few muscle bundles which extend from the dorsal surface of the lower sacral vertebrae or from the posterior Oiac spine to the dorsal surface of the coccyx. It hes beneath the superficial layer of the sacrotuberous (great sciatic) ligament.
The ilio-coccygeus (fig. 397) arises from the ischial portion of the arcus tendinous (white line). This extends from the iscliial spine and posterior part of the arcuate line to the superior ramus of the pubis near the obturator canal, curving downward for a variable distance below the obturator canal. The constituent fibre-bundles form a muscular sheet which is inserted into the side of the coccyx and into the median raphe (ano-coccygeal) which extends from the tip of the coccyx to the rectum. Many fibre-bundles cross the median hne.
The pubo-coccygeus (figs. 395, 397) arises from the inner surface of the os pubis, along a line extending from the lower margin of the symphysis pubis to the obturator canal, and from the arcus tendineus as far backward as the origin of the ilio-coccygeus. The fibre-bundles form a sheet of muscle which passes backward, downward, and medialward past the urogenital organs and the rectum on each side and is inserted by means of an aponeiu:osis into the anterior sacro-coccygeal hgament. Back of the rectum some of the fibre-bundles of the muscle sheets of each side interdigitate across the median line. Some of the more superficial fibres are inserted into the deep part of the ano-coccygeal raphe. Some of the fibre-bundles which arise nearest the symphysis are inserted on each side into the rectum. The pubo-coccygeus lies to some extent on the pelvic surface of the insertion of the ilio-coccygeus.
The pubo-rectalis (fig. 395) arises (a) from the body and descending ramus of the pubis beneath the origin of the pubo-coccygeus, (b) from the neighbom'ing part of the obturator fascia and (c) from the fascia covering the pelvic surface of the urogenital trigone. The fibre-bundles form a thick band on each side of the rectum behind which those of each side are inserted into the ano-coccygeal raphe. Many fibre-bundles may be traced into the muscle of the opposite side. Some of the more superficial fibre-bundles are reflected medialward in front of rectum and may be followed into the superficial transverse perineal muscle, others may be followed into the sphincter ani externus, or even to the skin.
the pelvic surface of the muscle and gives a special branch to each portion.
Action. — To flex the coccyx, raise the anus and constrict the rectum. It resists the downward pressure which the thoraco-abdominal diaphragm exerts on the viscera during inspiration. Relations. — Between the right and left muscles in front lie the m-ethra and the lower part of the prostate in the male, the urethra and vagina in the female. In the triangle between the ischio-pubic rami of each side lies the urogenital diaphragm separated from the pubo-rectal part of the muscle by the deep layer of the trigone from which some of the fibres of the latter arise. Back of the iirogenital diaphragm the muscle helps to bound the ischio-rectal fossa.
be variously described by different authors.
The sphincter ani externus (figs. 392, 394, 396, 397, 399) is made up of bundles of muscle fibres which surround the anus for nearly two centimetres. It is elliptical in form. Behind the anus the fibre-bundles of each side in part interdigitate, forming a ring. They are attached to the skin, and in part are attached through a tendon, the ligamentum ano-coccygeum, to the back of the coccyx. In front of the anus the fibre-bundles also in part interdigitate with one another, in part are inserted into the skin and in part interdigitate with the fibre-bundles of the transverse perineal and bulbo-cavernosus muscles. At the point where these muscles meet, about two and a half centimetres in front of the anus, there may be a visible mass of fibrous tissue, the central tendon of the -perineum, but this is not always distinct. It is usually better developed in the female than in the male perineum. The external sphincter is divisible into three portions, a subcutaneus, a superficial and a deep (fig. 397). The thi-ee parts are connected by fibre-bundles, and are not always distinct. The superficial division lies external to the subcutaneous ring and descends further toward the rectum. It is shown in figs. 392, 394. It is the only part attached to the coccyx. In front it is attached to the central tendon of the perineum, but some fibres are continued into the bulbo-cavernosus. The deep portion forms a heavy ring above the rectum beneath the superficial part. It is distinctly, though not completely, separated from the pubo-rectal portion of the levator ani by fascial tissue containing the inferior haemorrhoidal vessels. Some of the fibre-bundles of the deep portion may be traced in front of the anus across the mid-line to the ascending ramus of the opposite side and form part of the superficial transverse perineal muscle.
Relations. — Externally it is surrounded by the fat of the ischio-rectal fossa, internally near the skin it surrounds the sphincter ani internus, composed of smooth muscle, deeper it lies next the mucous membrane, for a distance of two centimetres from the skin.
The recto-coccygeus or muscle of Treitz, is a triangular bundle of smooth muscle fibres. The origin of the muscle is from the second and third coccygeal vertebrse. It is inserted by its apex into the posterior wall of the rectum and the perirectal fascia. It retracts and elevates the rectum.
perineal muscle and the urogenital sphincter.
The transversus perinei profundus (fig. 398) is a flat muscle which arises from the inner side of the inferior ischial ramus and is inserted into the median raphe. Many of the fibre-bundles interdigitate with those of the opposite side and some may be followed into the external sphincter of the anus and into the urogenital spincter and other perineal muscles.
give firm support for the action of the urogenital sphincter.
Relations. — The inferior surface is separated (often incompletely) by the inferior layer of the urogenital trigone from the superficial transverse perineal muscle. The superior surface is covered by the deep layer of the urogenital trigone, into which the superficial layer is reflected about the anal margin of the muscle.
The sphincter urogenitalis differs in the male and female owing to the passage of the vagina through the perineum in the latter. In each sex it is convenient to consider the muscle as divided into two parts, a peri-urethral and an infra-urethral (vaginal).
In the male (fig. 398) the peri-urethral part, the m. sphincter urethros memhranacece is composed of fibre-bundles which are circularly placed about the membraneous urethra. The more external fibre-bundles are attached to the crura of the penis near their junction, to the transverse ligament of the pubis and to the fasciae of the trigone. Some of them partially ensheath the lower part of the prostate, and others envelop the bulbo-urethral (Cowper's) glands. Some of the fibre-bundles take a longitudinal course along the urethra. Bundles of smooth muscle fibres are intermingled with the striated, and the fibrous framework of the musculature is marked by the large amount of elastic tissue which it contains. The infra-urethral part, the m. transversus urethrce, is closely associated with the urethral part. The fibre-bundles arise on each side from the inferior ramus of the pubis. They pass for the greater part beneath the urethra and interdigitate with that of the opposite side or are inserted into a median raphe. A few fibrebundles may pass above instead of below the urethra. The transverse urethral muscle, first described by Guthrie (On the anatomy and diseases of the neck of the bladder, London, 1834) is inconstant. Its existence as a normal constituent of the male perineal musculature has been disputed by Delbet (Poirier and Charpy) and others.
In the female the peri-urethral part, .•sphincter urethrce, differs in no essential respects from the corresponding muscle in the male. Some of the fibre-bundles form a true sphincter about the uretlu-a. The infra-urethral part, on the other hand, seems to vary gi'eatly in different individuals so that the descriptions given by different authors are somewhat contradictory. It is better developed in women who have not borne children than in those who have. It may be looked upon as composed of two portions, a m. transversus vagina and an m. constrictor vagince.
The iransversus vagince arises from the ischio-pubic rami and is inserted into the lateral wall of the vagina. Some of the fibre-bundles pass above and some below the vagina. This muscle corresponds with the transversus urethrce of the male but is, apparently, seldom fully developed. The m. constrictor vagince, on the other hand, seems to be more constant. It is composed of fibre-bundles which embrace the lateral wall of the vagina and are inserted above into the periurethral framework, below into the raphe between the two deep transverse perineal muscles. Some of the fibre-bundles are attached to the vaginal waU. Some interdigitate With the sphincter urethrae, others with the deep transverse perineal muscle and with the transversus vaginse.
Relations. — On the pelvic side it is separated from the levator ani by the deep layer of the urogenital trigone, and on the perineal side it is separated from the superficial muscles by the superficial layer of the trigone. Toward the anus it is closely associated with the deep transverse perineal muscle. Venous plexuses are well developed near the sphincter urethral in both sexes, but especially in the female.
Fig. 404. — Buibo-cavernostjs in the Male. The two halves have been reflected from the median raphe, and the bulb turned downward after division of the corpus spongiosum. (The isohio-bulbosus is not present on the right side.)
— It has already been pointed out that there is considerable variation in the muscles composing urogenital sphincter. Occasionally a rudimentary ischio-puhicus is found arising from the ischio-pubic ramus and terminating in a tendon which unites with that of the opposite side beneath the dorsal vein of the penis (clitoris). The tendon may be present as the transverse ligament of the pelvis when the muscle itseH is absent. It represents the compressor of the dorsal vein found in lower mammals.
C. External Genital Muscles
The bulbo-cavernosus (figs. 394, 404) in the male ensheaths the bulb. The fibre-bundles arise from the dense tissue covering the corpus cavernosum at the root of the penis and from the subpubic connective tissue dorsal to the bulbar part of the urethra and are inserted into its median raphe on the ventral side of the bulb and into the central tendon of the perineum. Several parts may be more or less clearly distinguished.
2. The compressor bulbi proprius arises (1) from a strong fibrous aponeurosis situated between the corpus spongiosum and the united crura of the penis and firmly adherent to the former, and (2) from the superficial layer of the trigone. The fibre-bundles ensheath the bulb aim are inserted into the posterior part of the median raphe and into the central tendon of the
compressor covers the more posterior part of the constrictor.
3. The compressor hemisphcerium bulbi arises from a tendon common to the muscles of the two sides on the dorsum of the bulbous part of the uretlira near the membranous part. The fibre-bundles embrace the hemisphere of the bulb and are inserted into the median raphe. This muscle is covered by the preceding. It not only compresses the bulb, but also is a sphincter of the urethra.
4. The ischio-bulbosus is placed by Holl in this group. It arises from the pelvic surface of the tuberosity and of the inferior ramus of the ischium and when well developed is inserted into the median raphe, superficial to the compressor bulbi proprius or the constrictor radicis proprius. Frequently, however, it does not extend over the bulb but is inserted into the inferior surface of the corpus cavernosum. It is more frequently absent than present. (See fig. 404.)
raphe and are united to those of the opposite side by a tendon which passes over the dorsal vein.
The hulbo-cavernosus (sphincter vagince) (fig. 392, 405) in the female arises (1) from fibrous tissue dorsal to the clitoris, (2) from the tunica fibrosa of the corpus cavernosum and from the superficial layer of the urogenital trigone in the angle between the crura of the ohtoris. The fibre-bundles form a band of tissue about two centimetres wide at the side of the vagina and are inserted into the posterior part of the superficial (inferior) layer of the trigonum and into the central tendon of the perineum where some of the fibre-bundles interdigitate with those of other muscles attached here. The fibre-bundles arising from the back of the clitoris correspond with those of the constrictor radicis penis in the male. The other fibre-bundles correspond with those of the compressor bulbi proprius in the male.
It is covered by skin and superficial fascia.
The ischio-cavernosus (figs. 398, 405) (erector penis or clitoridis) arises from the pelvic surface of the tuberosity and inferior ramus of the ischium, back and on each side of the attachment of the crus. The fibre-bundles form a thin sheet which is spread over the crus into the medial and inferior surfaces of which it is inserted near the symphysis pubis. It is better developed in the male than in the female.
The transversus perinei superficialis (figs. 392, 394, 405) arises from the inferior ischial ramus. The fibre-bundles extend in front of the rectum superficial to the deep transverse muscle and are inserted into the central tendon of the perineum. Some cross to the opposite side. Some of the fibre-bundles are continuous with those of the external sphincter or of the puborectalis of the opposite side.
The lower limbs are used chiefly for the support and propulsion of the body. Variety of movement is subordinated to strength and precision. In contrast with the upper limbs, which perform a vast variety of complex movements under conscious control, the lower limbs are called upon to perform chiefly the relatively simple movements which are used in walking or running, without our paying much attention to them.
The contrast between the two extremities is best marked in the girdles, the relations of which to the trunk have already been described, p. 444. The shoulder girdle is constantly called upon for movements in various directions which increase the freedom of action of the whole extremity. The sterno-clavicular and acromio-clavicular joints are movable so that the scapula can be carried in various directions over the thorax. The bones of the hip-girdle on each side, on the other hand, are ossified into a single hip-bone (os innominatum). The two hip-bones are almost immovably united to one another in front by the symphysis pubis and behind each is united to the sacrum by a joint which, although a diarthrosis, likewise permits but sUght movement. The sacrum in turn is composed of vertebrre firmly ossified together. The pelvis, composed of the two hip-bones and the sacrum forms a strong support for the trunk. Such movements as it makes are due chiefly to the lumbo-sacral joint and to a less extent to the joints between the lumbar vertebrae. These joints permit the pelvis, in a limited manner, to be flexed and extended, abducted, adducted, and rotated. Flexion is produced by the rectus and the oblique muscles of the abdomen (fig. 387) and by the psoas muscles (fig. 406), extension is produced by the quadratus lumborum (fig. 406) and the sacrospinahs (fig. 381). Rotation and abduction are produced when these muscles act on one side only. The weight of the body in the sitting posture is transmitted through the sacrum and hip-bones to the ischial tuberosities. In this position the pelvis is flexed. The weight of the body in the standing position is transmitted to the femora through the acetabulum on each side. In this position the pelvis is extended. In walking the pelvis is rotated forward toward the limb that is being advanced.
The hip-joint is a true ball-and-socket joint, but freedom of movement is greatly limited by the powerful musculature which surrounds it, as well as by the ligaments. Movements here, however, are freer than at the shoulder-joint, if the shoulder girdle be left out of consideration. At the hip-joint the most frequent and most free movements are those of flexion and extension, the main movements in'walking or running; but abduction, adduction, circumduction, and rotation are of the greatest importance in balancing the body.
At the knee-joint the main movements are also those of flexion and extension and the musculature is so arranged that the chief flexors of the knee which lie at the back of the thigh are extensors of the hip (fig. 408) while the extensor musculature of the knee which lies at the front of the thigh flexes the hip (fig. 411). Flexion of the hip, however, through the action of gravity on the foot passively brings about flexion at the knee, while flexion of the knee likewise passively brings about flexion of the hip, since the flexed knee tends to swing forward. These passive movements, due to gravity, are of importance in walking. The gastrocnemius (fig. 413), the most powerful extensor of the ankle-joint, is also a powerful flexor of the knee-joint. At the knee-joint, in addition to flexion and extension, some rotation is possible, best marked when the knee is flexed. This rotation is of value in walking over rough ground in that it helps to accommodate the foot to the ground. It is also of value in sitting on a flat surface. Whfle there is thus some rotation at the knee-joint not found at the elbow-joint, the free movement of the radius about the ulna which accompanies pronation and supination in the forearm, is unrepresented in the leg where the fibula is firmly united to the tibia at each end.
The joint between the bones of the leg and the tarsus permits merely of flexion and extension in contrast to the wrist-joint which also permits of adduction and abduction. Flexion and extension are also more limited iit the ankle than at the wrist. On the other hand, the movements of inversion and eversion which take place in the intertarsal joints are not needed in the wrist because of the pronation and supination of the forearm. Inversion and eversion of the foot are of value in walking on rough ground.
The movements of the toes resemble those of the fingers except that they are, in most individuals, far more restricted. The greatest restriction is seen at -the joint between the metatarsal of the big toe and the tarsus, as compared with that between the metatarsal of the thumb and the carpus.
which correspond with the musculature on the dorsal and ventral sides of the (shark's fin. The dorsal musculature is supplied by nerve branches which arise from the back of the lumbo-dorsal plexus ("femoral, gluteal, and peroneal nerves), the ventral musculature by branches which arise from the front of the plexus obturator and tibial nerves). Owing, however, to the rotation which the limb makes during embryonic development, the musculature which primitively lies on the dorsal side of the limb-bud comes to lie on the front and lateral side of the extremity and the musculature of the ventral side of the limb-bud comes to lie on the back and medial side of the extremity or in the sole of the foot. The side of the limb which primitively was toward the head becomes the medial side of the limb, and that which faced caudalward comes to lie laterally. While this makes the primitive relations of the musculature of the limb at first somewhat confusing, it is possible to approximate these primitive conditions by abducting the limb and rotating it so that the sole of the foot faces forward. An understanding of the innervation of the limb is thus greatly facilitated.
In the region of the hip the musculature of the dorsal division is that which arises from the spinal column and ilium and is inserted into the upper part of the femur and into the fascia of the thigh. It includes the chief flexor of the thigh, the ilio-psoas (fig. 406), and the most powerful extensor, the gluteus maximus (fig. 413), as well as several important rotators and abductors, gluteus medius and minimus, piriformis and tensor fascice latce (fig. 408) . The ilio-psoas is innervated by nerves from the back of the lumbar, the other muscles by nerves from the back of the sacral plexus. The musculature of the ventral division arises from the pubis and ischium, is inserted into the femur near the great trochanter and serves to adduct the thigh and rotate it lateralward, obturator internus, gemelli, quadratus femoris (fig. 408) and obturator externus (fig. 406). The obturator externus is innervated by the obturator nerve from the front of the lumbar plexus, the other muscles by special branches from the front of the sacral plexus.
In the thigh there are three well-marked groups of muscles, an anterior or extensor group (fig. 411), a medial or adductor group (fig. 411), and a posterior or flexor group (fig. 408). The anterior group belongs to the primitive dorsal division, the other two groups to the ventral division.
The muscles of the anterior group (fig. 411) the sartorius and quadriceps arise from the ilium and the shaft of the femur and are inserted into the tibia. The quadriceps flexes the thigh and extends the leg. The sartorius flexes both the thigh and the leg and rotates the former lateralward, the latter medialward. They are innervated by the femoral nerve. The muscles of the medial group (fig. 411), gracilis, pectineus, adductor brevis, longus, and magnus, arise from the pubis and the inferior ramus of the ischium and are inserted into the shaft of the femur. They adduct and fiex the thigh. They are innervated by the obturator nerve. The adductor magnus gets part of its nerve-supply from the sciatic. The pectineus usually gets all or most of its supply from the femoral. The reasons for including it in this group are given below. The posterior group (fig. 408) consists of the semitendinosus and semimembranosus, which arise from the ischial tuberosity, and of the biceps, one head of which also arises from the ischial tuberosity while the other arises from the shaft of the femur. The semimembranosus and semitendinosus are inserted into the tibia, the biceps into the fibula. They are innervated by branches of the sciatic. They extend the thigh and flex the knee. The semitendinosus rotates the leg medialward, the biceps lateralward.
In the leg there are also three groups of muscles, an anterior, a lateral and a posterior. The two former belong to the dorsal division and are innervated by the peroneal nerve. The last belongs to the ventral division and is innervated by the tibial nerve. The muscles of the anterior group (fig. 415), the tibialis anterior, extensor digitorum longus, peroneus tertius and extensor hallucis longus, arise from the tibia and fibula and are inserted into first and fifth metatarsals and into the two distal rows of phalanges. They flex the ankle and extend the toes. The extensor digitorum longus and peroneus tertius evert the foot. The muscles of the lateral group (fig. 415), the peroneus longus and brevis, arise from the fibula, send tendons behind the lateral malleolus and are inserted respectively into the first and the fifth metatarsals. Thej^ extend and evert the foot. The posterior group (figs. 413, 416) may be separated into two subdivisions, a superficial and a deep. The superficial subdivision (fig. 413) consists of the gastrocnemius, which
arises from the two epicondyles of the femur, and the soleus which arises from the tibia and fibula. These powerful extensors of the ankle are inserted by means of the tendon of Achilles into the calcaneus. The gastrocnemius is a flexor of the knee as well as an extensor of the ankle. A rudimentary muscle, the plantaris, arises near the lateral head of the gastrocnemius and is inserted into the fibrous tissue of the heel.
The deep group ("fig. 416) consists of one muscle, the popliteus, a medial rotator and flexor of the leg, which arises from the lateral condyle of the femur and is inserted into the tibia; and of three muscles, the ^exor digitorum longus, flexor hallucis longus and tibialis posterior, which arise from the tibia and fibula, send tendons behind the medial malleolus and are inserted into the plantar surface of the tarsus and into the terminal phalanges of the toes. They invert the foot and fiex the toes.
In the foot one muscle on the dorsum represents the primitive dorsal division, the extensor digitorum brevis (fig. 418), supplied by a branch from the peroneal nerve. On the other hand the primitive ventral division is well represented in the sole of the foot, not only by the muscles associated with the long flexor tendons, quadratus plantae, lumbricales (fig. 420), but also by the short flexor of the toes (fig. 419), by the special musculature of the big and little toes (fig. 421) and by the interosseous muscles (fig. 422). The flexor digitorum brevis (fig. 419), the most superficial of these muscles, arises from the calcaneus and is inserted into the second row of phalanges of the four more lateral toes. The quadratus plantce arises from the calcaneus and is inserted into the tendon of the long extensor of the toes. It makes the action of the tendon on the digits more direct. The four lumbrical muscles run from this tendon to the medial sides of the four lateral toes. They flex the digits. Of the intrinsic muscles of the great toe (figs. 419, 421), the abductor arises from the calcaneus; the flexor brevis from the cuneiform bones; and the adductor, by one head from the long plantar ligament, by the other from the capsules of the metatarso-phalangeal joints. All are inserted into the base of the first phalanx. Of the muscles of the little toe (figs. 419-421), the abductor arises from the calcaneus, the flexor and opponens from the cuboid. The two former are attached to the base of the first phalanx, the last to the fifth metatarsal. The interosseous muscles which arise between the metatarsals are so arranged that the three plantar abduct and the four dorsal adduct the four lateral toes to and from an axis passing through the second toe. The muscles of the sole of the foot which send tendons to the sides of the bases of the first row of phalanges help to flex the digits on the metatarsals and to extend the toes at the first row of interphalangeal joints. These are much less effective extensors of the phalanges than are the corresponding muscles of the hand and, unlike the latter, seem, in most individuals, to exert but little extensor action on the third row of phalanges. The muscles of the sole of the foot are supplied by the lateral and medial plantar branches of the tibial nerve.
The muscle fasciae of the inferior extremity are well developed. The fascia lata, which •encloses the musculature of the back of the hip and the musculature of the thigh, is especially strong on the lateral side where it includes the longitudinal bundles of fibres which compose the iho-tibial band. From the fascia lata strong intermuscular septa extend on each side of the quadriceps group of muscles to the femur. Medially beneath the sartorius muscle (fig. 410), septa help to bound Hunter's canal in which lies the femoral artery on its way to the pophteal space behind the knee. In the leg there is hkewise a strong cylindrical fascial sheath which encloses the musculature and sends septa on each side of the peroneal group to the fibula. A transverse septum also separates the deep from the superficial muscles of the calf. The fascia of .the leg is especially well developed near the anlde where it helps to hold in place the tendons which pass from the muscles of the leg into the foot. Muscle fasciae are well developed both on the dorsum and in the sole of the foot.
The ihac blade divides these muscles into an anterior group (ilio-psoas), supplied by nerves from the lumbar plexus, and a posterior group (the gluteal muscles, piriformis, and tensor fasciae latse, supplied by nerves from the sacral plexus.
In most of the limbed vertebrates these two groups of muscles are represented, but they present marked specific variations in the different forms. Primitively, the iliacus group lies on the proximal portion of the lateral surface of the iUum.
The fan-shaped iliacus muscle arises from the iliac fossa. The fusiform psoas major muscle arises from the sides of the last thoracic and of the lumbar vertebrae and extends along the medial margin of the iliacus muscle. The two muscles are inserted by a common tendon into the lesser trochanter of the femur. Together they constitute the ilio-psoas muscle. The small, flat, fusiform psoas minor lies on the medial surface of the psoas major and extends from the twelfth thoracic vertebra to the ilio-pectineal eminence. The ilio-psoas flexes the thigh at the hip and the pelvis on the trunk. The psoas minor aids in flexing the pelvis.
The ilio-psoas muscle arises in the human embryo from a blastema which at first surrounds the femoral nerve and later extends proximally over the ihum (iliacus) and toward the lumbar vertebrae (psoas). The iliacus is phylogenetically the more primitive. In the shoulder it is probably represented by the infraspinatus. The psoas minor is much better developed in many of the lower mammals than in man.
The fasciae and the relations of these muscles are shown in figs. 384 and 407.
The iUac and psoas muscles are covered by a dense fascia which is but sHghtly adherent to the underlying muscles. It is best developed in the pelvic region, where it extends from the iliac crest and ilio-lumbar ligament to the iliac portion of the linea arcuata and is called the iliac fascia. Superiorly it is continued over the psoas muscle as the psoas fascia and is attached medially to the sacrum and the lumbar region of the spinal column. Laterahj' it unites with the lumbar fascia and superiorlj' it is strengthened to form the medial lumbo-cosfal arch (fig. 391). Infiriorly the ilio-pectineal fascia extends over the iUo-psoas muscle to its femoral insertion. It is firmly united on each side of the muscle to the capsule of the hip-joint and to the femur. As it passes beneath the inguinal ligament it is united to this by tendinous processes. Beyond the ligament it is less dense than in the pelvic region.
The psoas major (figs. 406, 411). — Origin. — (1) By a series of thick fascicuh from the intervertebral discs between the tweKth thoracic and the fifth lumbar vertebra, from the adjacent parts of the bodies of these vertebrae and from tendinous arches which bridge over the middle of the sides of the first four lumbar vertebrae ; and (2) by a series of more slender fascicuh from the lower borders and ventral surfaces of the transverse processes of the lumbar vertebrae.
Structure and insertion. — From these origins parallel fibre-bundles descend nearly vertically and give rise to a fusiform muscle which hes at the side of the vertebral bodies and extends along the border of the true pelvis toward its insertion. A tendon arises deep in the muscle near the last lumbar vertebra, and becomes free on its dorso-lateral surface slightly above the inguinal (Poupart's) ligament. On the medial side the attachment of fibre-bundles continues to the insertion of the muscle into the small trochanter. The Uiacus muscle is attached to the lateral side of the tendon from near the ilio-pectineal eminence downward.
The iliacus (figs. 406, 411). — Origin. — (1) From the iliac crest, the ilio-lumbar hgament, and the greater part of the iliac fossa, the anterior sacro-iliac ligaments, and often from the sacrum, and (2) from the ventral border of the ilium between the two anterior spines.
Structure and insertion. — From these areas of origin the fibre-bundles pass to be inserted — (1) in a penniform manner on the lateral surface of the tendon which emerges from the psoas above the inguinal (Poupart's) ligament, and (2) directly on the femur immediately distal to the small trochanter. The lateral portion of the muscle arise from the ventral border of the ilium and is adherent to the direct tendon of the rectus femoris and the capsule of the hip-joint. It is sometimes more or less isolated (m. iliacus minor, ilio-capsulo-trochantericus, etc.).
Nerve-supply. — Nerve branches, often united in a plexiform manner, arise from the femoral (anterior crural) nerve and pass across the surface of the Uiacus muscle about midway between the crest of the ilium and the combined iUo-psoas tendon. Special nerve branches are usually likewise distributed from the main trunk of the femoral nerve to the fleshy portion of the muscle which extends over the acetabulum and the head of the femur.
Relations. — The psoas major lies lateral to the lumbar vertebrae and in front of the quadratus lumborum and intertransverse muscles. The psoas minor passes downward across its ventral surface. Both psoas muscles are crossed by the crura of the diaphragm. The kidney with its adipose capsule lies lateral to them opposite the first two lumbar vertebriB. For the rest, their fascia is covered ventro-laterally by retro-intestinal and retro-peritoneal tissue in which the vena cava inferior runs in front of them on the right side, the inferior mesenteric vein in front of them on the left side, and the ureter, the spermatic or ovarian, and the renal and colic vessels on each side. The external iliac artery lies medial to the psoas major in the pelvis, and beyond the inguinal (Poupart's) ligament the femoral artery hes ventral to it. The lumbar plexus arises
between its origins from the vertebral bodies and discs and those from the transverse processes. The nerves springing from the lumbar plexus take courses subject to much individual variation through the muscle on the way to their destinations. Fasciculi of the muscle may thus be separated by the femoral (anterior crural) nerve or other branches of the lumbar plexus.
The iliacus muscle in the region of the pelvis is covered by retro-peritoneal fat. The psoas muscle crosses its medial margin and from between the two muscles the femoral nerve usuaUy emerges to pass into the thigh above the iliacus. Beyond the inguinal ligament the iliacus lies in front of the capsule of the hip-joint and the straight tendon of the rectus femoris, and is crossed by the sartorius.
rotator and adductor. It also serves to flex the lumbar region of the spine.
Variations. — The psoas muscle may be separated from the Uiacus as far as the femoral insertion. The part of the psoas arising from the distal lumbar vertebrae may form a distinct muscle. Slips may pass from the psoas major to the psoas minor. A separate lamina of the iliacus muscle may be attached to the iliac fascia. From the anterior inferior iliac spine a small muscle slip may run to the intertrochanteric line or the ilio-femoral ligament. To this slip the term iliacus minor has been applied as well as to the larger fasciculus mentioned above.
and the intervening disc.
Structure and insertion. — The fibre-bundles pass to be attached as far as the level of the fifth lumbar vertebra to a flat tendon which appears about the mid-lumbar region and is inserted into the ilio-pectineal eminence. It is intimately united to the iUac fascia.
B. iliopectinea. — A large bursa between the ilio-psoas muscle, the ilio-pectineal eminence, and the capsule of the hip-joint. B. iliaca subtendinea. — A small bursa between the tendon of insertion of the ilio-psoas and the lesser trochanter.
The muscles of this group arise from the ilium and sacrum, cover the dorsolateral surface of the hip, and are inserted into the great trochanter and shaft of the femur and into the iho-tibial band. They lie in three planes. In the first layer (fig. 387) are the flat, quadrilateral tensor fasciae latae, which arises from the front of the crest of the ilium and is inserted into the ilio-tibial band, and the thick, rhomboid gluteus maximus, which arises from the dorsal portion of the ihac ala, the lumbo-dorsal fascia, the sacrum and coccyx, and the sacro-tuberous (great sacro-sciatic) ligament, and is inserted in part into the ilio-tibial bandand in part into the back of the upper part of the shaft of the femur. The ilio-tibial band is a flat tendon which descends, closely fused with the fascia lata, to the lateral side of the upper extremity of the tibia. In the second layer (fig. 408) are the flat, thick, triangular gluteus medius and the 'pear-shaped' piriformis The former arises from the upper and back part of the outer surface of the ala of the ilium, the latter from the ventral surface of the sacrum and the posterior border of the great sciatic notch. Both are inserted into the top of the great trochanter. The third layer (fig. 409) is composed of the triangular gluteus minimus, which arises from the inferior ventral portion of the outer surface of the ala of the ilium, and is inserted into the front of the great trochanter of the femur.
The muscles of this group extend, flex, abduct, and rotate the thigh at the hip. The gluteus maximus and medius are in part extensors, the gluteus minimus and the tensor fasciae latae are flexors of the hip-joint. All the muscles serve to abduct, the gluteus maximus acting thus when the hip is flexed. When the thigh is extended the lower part of the gluteus maximus is an adductor. The gluteus maximus and posterior part of the gluteus medius and the piriformis act as lateral, the anterior part of the gluteus medius, the gluteus minimus, and the tensor fasciae latae as medial, rotators. The gluteus maximus and the tensor fasciae latae through the iho-tibial band keep the extended knee-joint firna. The gluteus maximus is supphed by the inferior gluteal nerve, the piriformis by special nerves, and the other muscles of the group by the superior gluteal nerve. All these nerves arise from the upper part of the back of the sacral plexus.
The gluteus medius, gluteus minimus, and piriformis form a group of muscles which in the embryo have a common origin and are more or less fused in the adult. The gluteus maximus arises in two distinct, though associated, portions, and the tensor fasciae latae as another^ distinct portion. The two muscles, however, are probably to be considered as parts of a primitive caudo-pelvo-tibial musculature, while the gluteus medius group is represented in the lower forms by an iho-femoral musculature. The former group is often closely associated with the extensor muscles of the thigh in the lower forms (frog), and in some of the lower mammals extends its insertion to the plantar fascia (ornithorhynchus). In the arm this group is perhaps represented by the deltoid, the latissimus dorsi, and the teres major, while the gluteus medius group is represented by the subscapularis.
The tela subcutanea of the gluteal region is very thick, contains much fat, and is often divisible into two layers, of which the deeper is closely adherent to the fascia lata and through this to the gluteus maximus. Over the great trochanter a subcutaneous bursa is usually found (bursa trochanterica subcutanea).
Muscle fascia. — The muscles of the hip and thigh are enclosed in a dense fascia, the fascia lata (figs. 387, 407). This arises from the tuber isohii, the sacro-tuberous (great sacro-sciatic) ligament, the back of the sacrum and the coccyx, the crest of the iUum, the inguinal (Poupart's) ligament, and the pubic and ischial rami, and extends to the tibia and the fascia covering the muscles of the leg. It is composed mainly of bundles of fibres running transversely to the long axis of the limb. In the region of the gluteal groove it is strengthened by a transverse fibrous band which arises from the tuberosity of the ischium and arches upward over the lower border of the gluteus maximus muscle.
In the region of the hip the fascia lata invests both surfaces of the tensor fasciae latae and the gluteus maximus, and is closely bound to these muscles through intramuscular septa. Between these two muscles the fascia covers the fascia of the gluteus medius, to which it is adherent near the ihac crest, but from which it is sejjarated by loose tissue more distally. Anteriorly the fascia is fused with the IMo-pectineal fascia and the inguinal (Poupart's) ligament.
More distally the tendons of the tensor fasciae latse and of the superficial portion of the gluteus maximus become incorporated with the deep surface of the fascia lata and give rise to the ilio -tibial band [tractus iliotibialis].
C. Section through the muscles of the left inguinal region parallel to the inguinal (Poupart's) ligament (after Spalteholz). h in the diagram indicates Section B, fig. 384, p. 421; a' and h' indicate sections A and B, fig. 410, p. 465. (For legends, see p. 459.)
The gluteus medius and minimus muscles are invested by adherent fascial sheets which, ventrally between the two muscles, may be combined into an intermuscular septum or be so shghtly developed that the muscles are fused. The fascial sheet covering the gluteus medius toward the iliac crest is fused with the deep surface of the fascia lata. This fusion results in the formation of septa between the gluteus medius and the gluteus maximus and tensor fasciae latae.
GLUTEUS MAXIM US 459
The piriformis in the pelvic cavity is covered on the anterior surface by a special slightly developed fascia. This fascia also covers the pelvic surface of the sacral plexus. Outside the pelvis the piriformis is covered by an adherent membrane which usually is separated by loose tissue from the surrounding structures.
I. First Layer
The tensor fascise latae (figs. 387, 411). — Origin. — (1) By a tendinous band from the external lip of the iliac crest, and the upper part of the notch between the anterior superior and anterior inferior spines of the ilium, and (2) from the septum between it and the gluteus medius.
Structure and insertion. — The nearly parallel fibre-bundles pass distally and laterally and are united to tendon fasciculi which become incorporated with the ilio-tibial band (traotus iliotibiaUs) about one-third of the way down the thigh.
vastus laterahs.
Variations. — It may be divided into two parts, one rising from the anterior superior spine, the other from the iliac crest. Accessory slips may arise from the inguinal ligament, the crest of the ilium, or the fascia over the lower part of the abdominal wall. Union of the muscle with the gluteus maximus has been observed, thus making a muscle much resembling the deltoid of the shoulder. By some the fascia lata between the tensor and the gluteus maximus is considered an atrophied part of a deltoid of the hip.
The gluteus maximus (figs. 387, 413). — Origin. — (1) From the dorsal fifth of the outer lip of the iliac crest, the outer surface of the ilium dorsal to the posterior gluteal line, the lumbodorsal fascia between the posterior superior spine of the ilium, and the side of the sacrum, and (2) from the lateral portions of the fourth and fifth sacral and the coccygeal vertebrae and from the back of the sacro-tuberous (great sacro-sciatic) ligament.
Structure. — The large fibre-bundles of which the muscle is composed take a somewhat parallel course from origin to insertion. From the areas of origin and the enveloping fascia fibrous bands extend into the muscle. The belly is divisible into two portions, a superficial and a deep. The division may be much more clearly recognised in the embryo than in the adult. The superficial portion is the larger, and includes all of that part of the muscle which springs from the ilium and the more superficial portion of that arising from the sacrum and the upper part of the coccyx. The deep portion includes that part of the muscle attached to the side of the sacrum and the coccyx, and to the sacro-tuberous ligament. The superficial portion and some of the fibre-bundles of the deep portion terminate in the iho-tibial band along a line extending from the great trochanter to the end of the upper third of the femur. The deep portion is inserted chiefly by a flat tendon into the gluteal tuberosity, and also directly into the adjacent portion of the origin of the vastus lateralis.
Nerve-supply. — Two branches (inferior gluteal) arising from the sacral plexus either separately or united, are usually given to the muscle. One of these curves anteriorly across the deep surface of the proximal superficial portion of the muscle in the middle third between the tendons
5. A. glutea inferior. 6. A. hypogastrica (internal iliac). 7. A. ihaca externa. 8. A. pudena interna (pudic) . 9. Bursa iho-peotinea. 10. B. trochanterica m. glutaei maximi. 11. Eminentia iliopectinea. 12. Fascia iliaca. 13. F. ilio-pectinea. 14. F. lata — a, ihotibial band. 15. F. obturatoria. 16. F. pectinea. 17. F. transversahs. 18. Femur — a, trochanter major; b, trochanter minor. 19. Funiculus spermaticus (spermatic cord). 20. — Lacuna vasorum. 21. Ligamentum ilio-femorale. 22. L. inguinale (Poupart's ligament). 23. L. lacunare (Gimbernat's). 24. L. saoro-tuberosum (great sciatic). 25. Musoulus adductor brevis. 26. M. adductor longus. 27. M. coccygeus. 28. M. gemellus inferior. 29. M. gluteus maximus. 30. M. gluteus medius. 31. M. gluteus minimus. 32. M. iliopsoas — a, psoas; 6. iliacus. 33. M. levator ani. 34. M. obliquus abdominis externus, aponeurosis. 35. M. obhquus abdominis internus. 36. M. obturator externus. 37. M. obturator internus. 38. M. pectineus. 39. M. quadratus femoris. 40. M. rectus femoris. 41. iVI. sartorius. 42. M. tensor fasciaj latae. 43. M. transversus abdominis. 44. M. transverso-spinales (multifidus). 45. M. vastus lateralis. 46. N. cutaneus femoris anterior (middle cutaneous). 47. N. cutaneous femoris posterior (small sciatic). 48. N. femoralis (anterior crural). 49. N. gluteus superior. 50. N. ischiadicus (great sciatic) — a, peronaeus communis (external popliteal) ;
6, tibialis (internal popliteal). 51. N. obturatorius. 52. N. pudendus. 53. N. sacralis I. 54. N. sacralis II. 55. N. saphenus. 56. Os ilium^a, spina anterior superior; 6, spina anterior inferior. 57. Os ischium. 58. Os pubis — a, spina (tubercle). 59. Prostata. 60. Truncus lumbo-saeralis. 61. Vena femoralis. 62. V. saphena magna. 63. V. iliaca e.xterna. 64. V. hypogastrica (internal iliac). 65. Vertebra sacralis I. 66. Vertebra sacralis II.
Action. — It is the most powerful extensor of the thigh. It also serves slightly to rotate the limb lateralward and to make tense the fascia lata, and through the iho-tibial band to keep the extended knee-joint steady. When the thigh is extended the major part of the muscle is an adductor but the upper part is a weak abductor. The whole muscle is an abductor when the thigh is flexed. It is brought powerfully into play in cUmbing and in walking up hiU.
Relations. — It is covered by the fatty superficial tissue of the buttock. It extends over the posterior portion of the ilium, the lateral surface of the sacrum and coccyx, the sacro-tuberoua ligament, and the great trochanter. It covers the tuber of the ischium in the standing but not in the sitting position. Immediately beneath the muscle lie portions of the gluteus medius, piriformis, obturator internus, gemelH, quadratus femoris, obturator externus, and hamstring muscles, and of the gluteal vessels and nerves and the sciatic nerve.
Variations. — Few anomahes are recorded. The deep distal portion of the muscle may be more isolated than normal in the adult. A special coccygeo-femoral muscle may run from the coccyx to the Unea aspera, or from the sacro-tuberous ligament to the fascia of the leg. A
special fasciculus, the ischio-femoralis, may arise from the tuberosity of the ischium and become inserted into the lower border of the muscle near the great trochanter. The sacral, ischial, or coccygeal origin may be lacking, or the origin of the muscle may be from the sacrum only.
the investing fascia.
Structure and insertion. — The fibre-bundles converge upon both surfaces of a broad tendon nearly to its insertion on an oblong impression on the postero-superior angle and the external surface of the great trochanter. The more posterior fibre-bundles of the superficial stratum of the ventral portion of the muscle cross obliquely those of the deeper dorsal portion near the tendon of insertion. From the tendon an aponeurotic extension is usually continued into the tendon of the vastus lateraUs.
Nerve-supply. — From the superior gluteal nerve a branch passes to the dorsal portion of the muscle and one or more twigs of the branch to the tensor f ascise latse enter the ventral portion of the muscle. The branches enter the middle third of the muscle between its tendons of origin and insertion. The nerve-fibres arise usually from the fourth and fifth lumbar and first sacral nerves. The branch to the dorsal portion of the muscle has a lower spinal origin than those to the ventral portion.
and the great trochanter.
Variations. — It may be divided into two distinct portions, or it may be fused with the piriformis or the gluteus minimus or botli. A special fasciculus may extend to the superior portion of the great trochanter.
The piriformis (fig. 408). — Origin. — From (1) the lateral part of the ventral surface of the second, third, and fourth sacral vertebrae; (2) the posterior border of the great sciatic notch; and (3) the deep surface of the sacro-tuberous (great sacro-sciatic) ligament near the sacrum.
Structure and insertion. — The fibre-bundles converge upon a tendon which is inserted upon the anterior and inner portion of the upper border of the great trochanter. The insertion of fibre-bundles continues nearly to the great trochanter. An accessory shp of insertion may pass to the gluteus minimus.
Nerve-supply. — From a nerve which arises either directly from the first or second sacral nerve or from a loop between them. The nerve enters the deep surface of the muscle in its middle third. There may be two or more nerves.
Relations. — Its ventral surface faces the sacral plexus, the rectum, and the hip-joint. It is covered dorsaUy by the gluteus maximus. It hes between the gluteus medius and the superior gemellus. Between the piriformis and the superior gemellus the sciatic nerve usually passes into the thigh. The superior gluteal nerve and vessels pass dorsall}' above its superior margin; the inferior nerve and vessels beneath its inferior margin.
Variations. — It is rarely absent. The origin may extend to the first sacral or to the fifth sacral vertebra and the coccyx. It may be fused with the gluteus medius or minimus or more rarely with the superior gemellus. Its tendon of insertion may be fused with that of the gluteus medius or the obturator internus. In about 20 per cent, of bodies it is divided partly or completely into two portions, between which the sciatic nerve or its peroneal (external popliteal) division usually passes. Rarely the tibial instead of the peroneal portion may pass between the two fascicuh, or the muscle may be divided into three or more fasciculi, between which the branches of the sciatic nerve pass.
The gluteus minimus (fig. 409). — Origin. — From the outer surface of the ilium between the anterior and inferior gluteal lines; (2) from the septum between it and the gluteus medius near the anterior superior ihac spine; and (3) from the capsule of the hip-joint.
Structure and insertion. — The fibre-bundles converge upon a tendon which appears on the middle of the ventral border and gradually spreads over the lateral surface. The muscle is thickest in front, where it is usually bound by an intermuscular septum to the gluteus medius. The tendon is inserted into the ventral surface of the great trochanter of the femur.
is a flexor, the posterior an extensor.
Relations. — It is covered by the gluteus medius and piriformis muscles. Beneath it lie the inferior part of the iliac ala, the hip-joint (to the capsular ligament of which it is bound), and the direct tendon of the rectus femoris muscle.
an anterior and a posterior. Very frequently from the anterior margin of the muscle a special fasciculus is more or less isolated (the scansorius, invertor femoris, small anterior gluteal, etc.). The accessorius of the gluteus minimus is a small muscle fasciculus which may lie under cover of the gluteus minimus and extend to be inserted into the capsule of the hip-joifit.
Vastus medialis
present between the fascial tendon of the gluteus maximus and the posterior lateral surface of the great trochanter and the origin of the vastus lateralis muscle. B. gluteofemorales. — Two or three small burste on each side of the tendon of attachment of the gluteus maximus to the femur. B. trochanterica m. glutei medii anterior. — A small bursa constantly present between the tendon of the gluteus medius muscle and the lateral surface of the great trochanter. B. trochanterica m. glutei medii posterior. — A small bursa frequently present between the tendons of the piriformis and the gluteus medius. B. trochanterica m. glutei minimi. — A fairly large bursa generally present between the margin of the great trochanter and the tendon of this muscle. B. m. piriformis. — A small bursa frequently present between the tendons of the piriformis and superior gemellus muscles and the femur.
The muscles belonging to this group (the obturator internus, the two gemelli, the quadratus femoris and the obturator externus, extend from the pubis and ischium across the back of the hip-joint to the great trochanter and the neighbouring part of the shaft of the femur. They are powerful lateral rotators of the thigh. The obturator internus (fig. 409), a large, flat, triangular muscle, arises from the pelvic surface of the innominate bone and from the obturator membrane. At the lesser sciatic notch its tendon is joined by the two gemelli (fig. 408), one of which arises on each side from the bony projections which make the notch, and the combined tendon is inserted into the trochanteric (digital) fossa. The quadratus femoris (fig. 408) passes from the tuber of the ischium to the femur behind and below the great trochanter. These muscles are supplied by special nerves which arise from the front of the sacral plexus and enter the deep surfaces of the muscles. A fifth muscle, attached to the greater trochanter and associated with this group, the obturator externus, is differentiated near the adductor muscles of the thigh and is supplied by a branch from the obturator nerve. It arises from the outer surface of the bones bounding the ventral twothirds of the obturator foramen and is inserted by a tendon into the trochanteric (digital) fossa.
These muscles seem to have no certain representatives in the arm, where the shoulder-ioint is entirely ensheathed by the dorsal musculature. It is possible that the pectoral group has a corresponding embryonic origin. The group is represented, with marked variations, in the lower extremities of amphibia and aU higher vertebrates.
Within the pelvis the obturator internus hes on the obturator membrane. It is covered by the obturator fascia, which is attached to the body of the pubis, to the iliac portion of the arcuate line, to tlie ventral margin of the great sciatic notch, to the ischial spine, to the sacrotuberous (great sacro-sciatic) ligament, and with the falciform process of that Ugament, to the ischial and pubic rami. Near the upper part of the obturator foramen the fascia instead of being attached to bone is reflected over the muscle and attached to the obturator membrane. It here helps to bound the canal for the obtiu-ator vessels and nerve. The upper part of the fascia lies beneath the pelvic peritoneum and the levator ani. The lower part forms the outer boundary of the ischio-rectal fossa. The fascia is continued as a thin, adherent membrane over the obturator internus and the gemellus muscles to their attachment. The quadratus femoris is invested by a thin adherent fascial sheet.
The obturator internus (fig. 409). — Origin. — From (1) the pelvic surface of the pubic rami near the obturator foramen; (2) the pelvic surface of the iscliium between the foramen and the great sciatic notch; (3) the deep surface of the obturator internus fascia; (4) the fibrous arch which bounds the canal for tlie obturator vessels and nerve; and (5) the pelvic surface of the obturator membrane except in the lower part.
Structure and insertion. — From this extensive area of origin the fibre-bundles converge toward the lesser sciatic notch and become applied to the broad tendon of insertion. At the notch the muscle curves laterally and extends outward and upward to its insertion into the fore part of the trochanteric fossa of the femur. The tendon is formed of five or six bands which begin high in the muscle and converge into a common tendon situated on the deep surface of the muscle as the latter curves about the ischium. The tendon bands at first throw the tendon into folds which run in ridges in the fibro-cartilage which lines the notch. The attachment of fibre-bundles continues upon the dorsal surface of the tendon to half way between the lesser sciatic notch and the great trochanter.
Nerve-supply. — A special nerve to the obturator internus arises from the front of the sacral plexus, usually from the lumbo-sacral cord and the first and second sacral nerves. This nerve passes lateral to the sacro-spinous (lesser sciatic) ligament, then re-enters the pelvis through the lesser sciatic notch and sends out branches of distribution on the pelvic surface of the obturator internus.
of the thigh. It is also an extensor and abductor when the thigh is bent at a right angle.
Relations. — The chief pelvic relations have been described in connection with the obturator fascia which completely covers the medial surface of the muscle. The muscle passes out between the two sacro-ischial (sacro-sciatic) ligaments. Outside the pelvis the gemellus muscles run on each side of the tendon, which is here closely applied to the capsule of the joint. Dorsal to it lie the gluteus maximus, the sacro-tuberous (great sacro-sciatic) ligament, the inferior gluteal (sciatic) vessels, and the sciatic and posterior cutaneous nerves. The nerve of the quadratus femoris runs beneath the obturator internus and gemellus muscles.
a pubic and an ischial. Fasciculi may be sent to the postero-inferior part of the ilio-pectineal eminence, the tendon of the psoas minor, the tuber ischii, the sacro-tuberous (great sacro-sciatic) ligament, the ischial spine, etc.
and the neighbouring edge of the lesser sciatic notch.
Structure and insertion. — The fibre-bundles encircle the upper border and ventral aspect of the tendon of the obturator internus. They are inserted into the upper border of this tendon, and sometimes also into the trochanteric fossa.
Nerve-supply. — From a small nerve which arises either directly from the plexus or as a branch of the nerve to the obturator internus or of that to the quadratus femoris. This nerve usually enters the deep surface of the muscle near the junction of its ischial and middle thirds.
of the lesser sciatic notch.
Structure and insertion. — The fibre-bundles converge upon the inferior border of the tendon of the obturator internus, and are inserted by tendon-fibres into this or into the great trochanter below the obturator internus tendon.
into the vertical ridge which terminates above on the inferior dorsal angle of the great trochanter.
Nerve-supply. — ^From a nerve which arises usually from the lumbo-sacral cord and the first sacral nerve and passes under the gemelli and the tendon of the obturator internus. The nerve enters the deep surface of the muscle near the junction of the ischial and middle thirds.
Relations. — -It is covered by the gluteus maximus. Between this muscle and the quadratus femoris runs the sciatic nerve. The obturator externus muscle lies in front. The inferior gemellus extends along its superior border. The adductor minimus adjoins it distally.
Variations. — It is absent in from 1 to 2 per cent, of instances. (Schwalbe and Pfitzner.) It may be double near its femoral insertion. It may be fused with the inferior gemellus or the adductor magnus. It may send a fasciculus to the semimembranosus.
Structure and insertion. — ^Often the muscle is distally divided into three fasciculi, a superior from the superior pubic ramus, a middle from the inferior pubic ramus and the obturator membrane, and an inferior from the ischium. The fibre-bundles converge upon a tendon which is at first deeply buried, then appears on the lateral surface of the muscle and is continued as a rounded tendon over the capsule of the joint to its insertion into the dorsal part of the trochanteric fossa.
Relations. — It is covered by the pectineus, the ilio-psoas, and the adductor magnus muscles in front, and by the quadratus femoris behind near its insertion. It covers over the obturator membrane. The obturator nerve passes either above the muscle or through its upper portion.
B. m. obturatoris interni. — A fairly large bursa constantly present between the tendon of the obturator internus muscle and the lesser sciatic notch. It may extend on each side beneath the gemellus muscles. B. m. quadrati femoris. — A small bursa frequently found between this muscle and the small trochanter. B. m. obturatoris externi. — A bursa is sometimundes of between the tendon of this muscle and the capsule of the joint.
In the thigh three groups of muscles may be recognised, an anterior or extensor (figs. 411, 412), a medial or adductor (figs. 409, 411, 412), and a posterior, flexor or hamstring group (figs. 408, 413).
In the proximal part of the thigh the anterior group of muscles is separated from the medial group by the ilio-psoas muscle (fig. 411) and by the femoral blood-vessels and nerve, and from the posterior group by the gluteus maximus (fig. 413). More distally it is separated from the medial group by the medial intermuscular septum and from the posterior by the lateral intermuscular septum (see p. 468). The medial and posterior groups are closely associated. The adductor magnus belongs ontogenetically to both.
The three groups of muscles, with numerous modifications, are represented in the thighs of amphibia and all higher vertebrates. In the human arm they are likewise represented, the adductor group in a much reduced form by the coraco-brachialis. The quadriceps is represented by the triceps in the arm, the long head of the triceps corresponding with the rectus femoris. The hamstring muscles are represented by the biceps and the braohiahs.
sections figs. 407, 410, 414.
The tela subcutanea of the thigh varies considerably in thickness in different regions, but is well developed throughout and contains a considerable amount of fat. Over the front of the thigh, especially in the upper medial region, one or more deeper membranous layers may usually be separated from the superficial adipose layer. Between the former and the latter are situated the inguinal lymphatic nodes and the saphenous vein. The deepest layer near the inguinal (Poupart's) Ugament is fused with the fascia lata (see below). Medially it is attached to the pubic arch. Thus fluids beneath the tela subcutanea of the abdomen and perineum do not readily pass into the region of the thigh.
The muscles of the thigh are enclosed in a dense fascial sheet, the fascia lata (figs. 387, 410). The gluteal portion of this and the ilio-tibial band have already been described (p. 457). The ventral portion of the fascia, composed chiefly of transverse fibres, is a dense, fibrous membrane. Above it is attached to the inguinal Hgament from the anterior superior spine to the pubic tubercle. Below it extends over the knee, where it is united to the capsule of the joint and is strengthened by expansions from the vastus lateraUs and mediahs. Between the front of the patella and the fascia is a bursa (b. praspatellaris subfascialis). Above the knee the fascia is strengthened by an arciform process which extends obliquely distally across the fascia from the ilio-tibial band to the capsule of the knee. This gives rise to a fold in the skin when the leg is extended and the muscles are not tense. Over the medial and posterior regions of the thigh the fascia is less dense. It extends from the body and inferior ramus of the pubis, the inferior ramus and tuber of the ischium, and the sacro-tuberous ligament into the fascia of the back of the leg. Above the popUteal space it is strengthened by a transverse band of fibres. Near the knee the tendons of the quadriceps, sartorius, gracihs, and semitendinosus become bound to the fascia by membranous laminse.
The relations of the fascia lata to the inguinal ligament and the iliac fascia are somewhat complex. The fascia of the ilio-psoas muscle extends over the muscle to its femoral insertion. Above the inguinal ligament this fascia is called the fascia iliaca; below the ligament, the fascia ilio-pectinea. This fascia is firmly united to the lateral extremity of the inguinal ligament. The pectineus muscle is likewise invested with a fascial membrane which extends over the muscle from the pubis to the femur and is fused laterally with that of the ilio-psoas. This combined fascia is firmly bound between the two muscles to the ilio-pectineal eminence. The ilio-pectineal fascia divides the space beneath the inguinal ligament into a lateral lacuna musculorum, which contains the iUo-psoas muscle and the femoral (anterior crural) nerve, and a medial lacuna vasorum, which contains the femoral artery and vein. Medial to the vein is the femoral ring, bounded medially by the lacunar (Gimbernat's) ligament. This is closed off from the abdominal cavity by a septum derived from the transversahs fascia, the femoral septum, but offers passage for lymph-vessels.
a and 6 in the diagram indicate the regions through which pass sections A and B, fig. 407 (p. 458) ; 1. Arteria circumflexa femoris lateralis. 2. A. circumflexa femoris medialis. 3. A. femoraUs. 4. A. femoralis profunda. 5. A. glutea inferior (sciatic). 6. A. poplitea. 7. Bursa praepatellaris subfascialis. 8. Adductor (Hunter's) canal. 9. Fascia lata. 10. Femur — a, distal extremity. 11. Funiculus spermaticus (spermatic cord). 12. Musculus adductor brevis. 13. M. adductor longus. 14. M. adductor magnus. 15. M. biceps femoris — a, long head; b, tendon of origin; c, short head. 16. M. gastrocnemius — a, lateral head; b, medial head. 17. M. gluteus maximus. 18. M. gracihs — a, tendon. 19. M. rectus femoris — a, tendon. 20. M. sartorius. 21. M. semimembranosus — a, tendon. 22. M. semitendinosus • — a, tendon. 23. M. sphincter ani. 24. M. vastus intermedins (orureus) — a, tendon. 25. M. vastus lateralis — a, tendon. 26. M. vastus medialis — a, tendon. 27. Nervus cutaneous femoris anterior. 28. N. cutaneous femoris posterior (small sciatic). 29. N. gluteus inferior. 30. N. obturatorius — a, superficial branch; b, deep branch. 31. N. peroneus communis (external popliteal). 32. N. saphenus (great saphenous). 33. N. tibialis (internal pophteal). 34. Patella. 35. Septum intermusculare laterale. 36. Septum intermusculare mediale. 37. Tractus iliotibialis (ilio-tibial band). 38. Vena femoralis. 39. Vena poplitea. 40. V. saphena magna (great saphenous vein).
Beyond the inguinal ligament the fasciae of the ilio-psoas and pectineal muscles line a triangular space, the ilio-pectineal fossa,* through which run the femoral vessels (fig. 407). The sartorius muscle partly overlies the distal lateral margin of this fossa. The fascia lata is here reflected from the surface of the sartorius to the ilio-psoas fascia, and becomes fused with it. From the medial margin of the sartorius a process of the fascia is continued over the lateral and upper part of the fossa, and is attached to the inguinal and lacunar (Gimbernat's) liga-
Ligamentum patellse
ments (fig. 389). Over the lower extremity of the fossa a process is continued medially into the pectineal fascia. On the medial margin of the fossa the fascia lata is continued directly into the pectineal fascia. The lateral concave margin of the fascia overlying the fossa is called the falciform margin; the upper extremity of this, the superior cornu; the distal extremity, the inferior cornu. The oval space bounded by the margo falciformis is called the fossa ovalis (saphenous opening). This is covered by the fascia cribrosa, which some consider a deep layer
of the tela suboutanea and others a portion of the fascia lata. This fascia cribrosa contains many openings for the passage of blood-vessels and lymphatics. The space which lies medial to the femoral vessels between the femoral ring and the fossa ovahs is called the femoral canal (crural canal).
The lateral intermuscular septum separates the extensor muscles from the hamstring group. It extends from the tendon of the gluteus maximus to the lateral epicondyle. It is composed chiefly of longitudinal fibres and is thickest distaUy. The vastus lateraUs is united to its ventro-lateral surface; the short head of the biceps, to its dorso-medial surface.
It will be noted that this septum serves to divide primarily ventral from primarQy dorsal musculature, with the exception of the short head of the biceps, which, though primarily dorsal, occupies a position, perhaps secondarily acquhed, with the primarily ventral muscles.
The medial intermuscular septum serves to divide the anterior extensor from the medial adductor musculature. It is perhaps simplest in the region immediately distal to the iliopectineal fossa (fig. 410 B). Here a well-marked septum may be seen extending to the femur between the sartorius and quadriceps on the one side, and the adductor longus and brevis on the other. The septum here, next the muscles, has on each side a membranous lamina. Between the two laminae there is a looser tissue in which run blood-vessels and nerves. A fibrous membrane extends between the rectus and sartorius to the septum.
More distally the sartorius comes to overlie the septum (fig. 410 C). The sheath of the sartorius on the lateral margin becomes fused with the fascia of the vastus mediahs, and on the medial margin to a membrane that covers the ventral surfaces of the adductor longus and magnus. Beneath the sartorius and between the adductor longus and the vastus medialis is a triangular space bounded by the sheaths of these muscles, and fiUed with a loose areolar tissue in which run the chief blood-vessels of the thigh. This space, first described by John Hunter, is known as Hunter's canal, or the adductor canal. Still more distally the vessels with their surrounding fibrous tissue pass through the hiatus tendinous, between the long tendon of the adductor magnus and the femur, to the back of the thigh. The septum here passes behind the posterior surface of the vastus medialis to the femur.
nerve.
The sartorius is a long, ribbon-like muscle which arises from the anterior superior spine of the ilium and extends along the medial margin of the quadriceps, passing obliquely across the upper part of the thigh, and then descending to the dorse-medial side of the knee, whence its tendon curves forward to be inserted into the ventro-medial surface of the superior extremity of the tibia.
The quadriceps femoris is composed of four muscles differentiated from a common embr3'onic origin. Of these, the rectus femoris, which arises from the ventro-lateral margin of the ilium by two tendons, is the most superficial and the most completely differentiated. The vastus lateralis, which arises from the superior e.xtremity of the ventral surface of the shaft of the femur and from the lateral lip of the linea aspera; the vastus medialis, which arises from the medial lip of the linea aspera and from the intertrochanteric line; and the vastus intermedius (crureus), which arises between these two and beneath the rectus from the surface of the femur, are less distinctly differentiated from one another. The vastus intermedius and vastus laterahs are partly fused at the insertion, the intermedins and medialis at their origins. From the four muscles arises a tendon which is inserted into the tuberosity of the tibia. In this tendon, which is closely applied to the capsule of the knee-joint, lies a sesamoid bone, the patella.
SARTORIUS
Structure. — The muscle arises by short tendinous strands. The fibre-bundles take a nearly parallel course. The component muscle-fibres are said to be the longest in the body. Near the medial epicondyle of the femur the tendon of insertion makes its appearance on the deep aspect of the muscle. On the superficial surface of the tendon the muscle-fibres are inserted as far as the distal margin of the knee-joint. From there the tendon turns forward to its insertion.
Variations. — It may arise from the inguinal ligament or be inserted into the fascia lata, the medial epicondyle, or the capsule of the knee-joint. It may be longitudinally divided into two parts. The tendon of the secondary slip is in such instances usuaOy attached to the capsule of the knee-joint, but sometimes is attached to the fascia over the vastus medialis or to the anterior wall of the adductor canal. More frequently the muscle is partly divided proximally or distaUy. The secondary tendon of origin may arise from the anterior inferior spine, the ilio-pectineal eminence, etc. The muscle is very rarely absent. It may be crossed by a tendinous inscription, or more rarely it is rendered digastric by an intervening tendon.
rectus femoris and the vastus lateralis, intermedins, and medialis.
The rectus femoris (fig. 411). — Origin. — By two tendons. The anterior 'straight' tendon is attached to the anterior inferior spine of the ilium; the posterior 'reflected' tendon to the postero-superior surface of the rim of the acetabulum. The two tendons unite so as to form a small arch above the capsule of the joint.
Structure and insertion. — From this arch an aponeurotic expansion descends upon the front of the muscle nearly to the middle of the thigh. This expansion is broad above, becomes narrower as it descends, and is continued a short distance as a narrow intramuscular tendon after it disappears from the surface. The tendon of insertion begins on the back of the muscle above the middle of the thigh, expands into a broad aponeurosis, and finally becomes a strong band which is inserted into the proximal border of the patella. The fibre-bundles pass in a bipenniform manner from the back and sides of the tendon of origin to the front and sides of the tendon of insertion.
Nerve-swpply. — As a rule, two branches enter the muscle. One of these enters the deep surface of the muscle in its upper fourth, and is distributed mainly to the proximal part of the lateral half. The other enters the medial margin of the muscle near the junction of the proximal and middle thirds, and is distributed chiefly to the medial half and distal portion of the muscle.
The vastus lateralis (vastus externus) (fig. 412). — Origin. — From — (1) the shaft of the femur along the antero-inferior margin of the great trochanter and in front of the gluteal tuberosity; and (2) the lateral intermuscular septum along the upper half of the linea aspera.
front of the lateral condyle of the tibia and the fascia of the leg.
Structure. — The fibre-bundles arise partly from the bone, partly from an aponeurosis which covers the proximal two-thirds of the muscle, and from the lateral intermuscular septum. They take a parallel course distally in a ventro-medial direction, and are inserted into an aponeurosis which lies on the deep surface of the muscle and receives fibres until within a few centimetres of the patella. Ventrally this aponeurosis fuses with the rectus tendon, laterally with that of the vastus medialis, and dorsally it receives some of the fibre-bundles of the vastus intermedins. Commonly the muscle is distinctly divisible for the greater part of its course into two sheets, a superficial and a deep. The deep sheet is often subdivided into two laminae.
NerBe-supply. — Usually there are three nerves, one of which, accompanied by blood-vessels, runs on the inner surface of the superficial sheet midway between the tendons of origin and insertion, the second between the two laminae of the deep layer, and the third passes through the innermost lamina to be distributed in part to the vastus intermedins (crureus) muscle.
The vastus medialis (vastus internus) (fig. 412). — Origin. — From the whole extent of the medial lip of the linea aspera and from the distal half of the intertrochanteric line. The origin takes place by means of an aponeurosis which is adherent to the tendons of insertion of the adductor muscles.
Structure and insertion. — The fibre-bundles arise from the deep surface of this aponeurosis and are inserted on the medial surface and margin of a tendon which begins on the deep surface of the muscle about its middle near the lateral margin. On the distal lateral border of the muscle it is inserted into the medial half of the proximal margin of the patella and into the medial condyle of the tibia and the fascia of the leg. For some distance near the knee the lateral margin of the tendon is united to those of the vastus intermedins (crureus), lateralis (externus) and the rectus.
Nerve-supply. — The nerve to this muscle descends on its medial surface, often bound up with the saphenous nerve for a part of its course. It gives off successive branches and finally sinks into the muscle substance. These branches enter about midway between the origin and insertion of the fibre-bundles of the muscle.
The vastus intermedins (crureus) (figs. 409, 412). — Origin. — From (1) the distal half of the lateral margin of the linea aspera and its lateral bifurcation; (2) the antero-lateral siu'face of the shaft of the femur. Between the origin of the vastus intermedins (crureus) and that of the vastus medialis the shaft of the femui' is free from muscle attachment.
Structure and insertion. — On the ventral surface of the muscle lies an aponeurosis which extends from its proximal fourth to the proximal margin of the patella. The fibre-bundles of the muscle are inserted into the deep surface of this and into the deep surface of the aponeurosis of insertion of the vastus lateralis. The proximal fibre-bundles descend vertically, the medial and lateral, especially the latter, obliquely to their insertion. Medially the tendon is more or less fused with that of the vastus medialis, and laterally with that of the vastus lateralis. The muscle is composed of muscle lamelto superimposed concentrically about the shaft of the femur. The deepest, most distal of these is called the articularis genu (subcrureus). The fibre-bundles of this layer are inserted into the capsule of the joint or into the superior margin of the pateUa.
Nerve-supply. — Several branches are usually distributed to this muscle. To the lateral region a branch from the nerve to the vastus lateralis is usually given; to the middle of the muscle another branch descends from the femoral (anterior crural) nerve; to the medial portion there extend several twigs from the nerve to the vastus medialis.
ADDUCTOR MUSCLES 471
Tendon of the quadriceps. — The quadriceps tendon may be more or less distinctly divided into layers, of which the superficial layer belongs to the rectus, the deep to the vastus intermedins, and the intermediate to the vastus lateralis and medialis. Some of the more superficial fibres of the tendons of the two vasti, however, cross in front of the rectus tendon. The combined tendon of the quadriceps is in part attached to the superior and lateral margins of the patella, and in part extends over the patella into the patellar ligament. A part of the tendon fibres of the vastus laterahs and medialis run on each side of the patella to the ventral surface of the condyles of the tibia. These form the retinacula patellse mediate and laterale. The medial is the broader and better developed. With the retinacula are included bundles of fibres which run from the epicondyles to the patella and into which some muscle fibre-bundles are inserted. From the apex of the patella to the tuberosity of the tibia the quadriceps tendon is continued as the patellar ligament (fig. 415).
Nerve-supply. — The relations of the branches of distribution to the various parts of the muscle have been pointed out above in connection with each head. The general relations of these branches of the femoral nerve are as follows: — From the femoral nerve near the proximal end of the vastus medialis the branches for the vastus lateralis, vastus intermedins (crureus), and rectus pass distally and laterally between the rectus and vastus intermedins (crureus) to be distributed to the muscles named, while the chief nerve for the vastus mediahs descends on the medial side of this muscle in company with the saphenous nerve. The branches to the vastus lateralis and intermedins are commonly bound up in a single nerve-trunk for some distance. The branches to the rectus are usually bound up with this trunk for a shorter distance. The nerve to the vastus medialis may be united to this trunk for a slight distance, but more frequently it is more or less bound up with the saphenous nerve.
Relations. — The quadriceps is covered ventrally immediately by the fascia lata. The sartorius runs along its medial margin; the tensor fasciee latse lies over the proximal quarter of its lateral surface. Dorsal to the vastus lateralis lie the gluteus maximus and biceps; dorsomedial to the vastus medialis, the three adductor muscles and the semimembranosus. Next the vastus medialis lies the adductor canal with the femoral vessels and the saphenous nerve.
Variations. — The variations of this muscle, aside from a greater or less fusion of its parts, are not marked. The attachment of the rectus femoris to the anterior inferior spine, which takes place in the embryo later than its insertion above the acetabulum, may be wanting. On the other hand, this tendon may extend to the anterior superior spine. Occasionally the deep reflected tendon may be wanting. The rectus accessorius is a fasciculus rarely found, which arises by a tendon from the rim of the acetabulum and is inserted into the ventral edge of the vastus lateralis. It is innervated by a twig from the branch to the rectus.
B. m. recti femoris (superior). — A small bursa between the deep tendon of the rectus femoris and the edge of the acetabulum. Rare. B. m. recti femoris (inferior). — Between the tendon of the rectus and the combined tendon of the vastus lateralis and medialis. Occasional. B. praepatellaris subtendinea. — A bursa between the tendon of the quadriceps and the periosteum of the patella. Of the three prepatellar bursK — the subcutaneous, subfascial, and subtendinous — as a rule only one occurs. When two or three exist, they usually communicate freely with one another. B. suprapatellaris. — A bursa between the anterior surface of the lower end of the femur and the tendon of the quadriceps. It usually communicates with the joint cavity. B. infrapatellaris profunda. — A bursa between the patellar ligament and the tibia. It seldom communicates with the joint cavity. B. m. sartorii propria. — A bursa, fairly large, between the tendon of the sartorius and the tendons of the semitendinosus and gracilis muscles. This usually communicates with the bursa anserina (see p. 474).
To this group of muscles belong the gracilis, the pectineus, the adductors brevis, longus, and magnus, and the obturator externus. The most superficial of the group is the gracilis (figs. 408, 411). This ribbon-shaped muscle arises from the inferior pubic and ischial rami, extends along the medial side of the thigh, and gives rise to a tendon which curves forward from behind the medial condyle of the femur to be inserted under the tendon of the sartorius into the medial side of the upper extremity of the tibia. The quadrilateral pectineus arises from the body and superior ramus of the pubis; the triangular adductor longus from the superior ramus medial to this (fig. 411). The pectineus is inserted into the pectineal line of the femur; the adductor longus into the middle third of the linea aspera. The triangular adductor brevis (fig. 412) arises from the inferior pubic ramus below the adductor longus. It is inserted into the pectineal line and the upper third of the linea aspera. The large, triangular adductor magnus (figs. 409, 412) arises from the inferior ramus and the tuber of the ischium and is
inserted behind the short and long adductors into the whole length of the linea aspera, and by a special tendon into the adductor tubercle of the femur. The deepest muscle of the group, the obturator externus, which arises from the outer surface of the bones bounding the ventral two-thirds of the obturator foramen, and is inserted by a tendon into the trochanteric (digital) fossa, has been described in connection with the ischio-pubo-femoral muscles of the hip.
All the muscles of this group adduct the thigh. The gracilis, obturator externus, adductor brevis and the lower part of the adductor magnus (when the thigh is extended) rotate it lateralward. The pectineus, adductor longus, and the adductor magnus rotate it medialward. Those attached to the pubis flex the thigh. The gracilis flexes the leg and rotates it medialward. The inferior part of the adductor magnus extends the thigh.
The muscles of this group are supplied by the obturator nerve, except the pectineus, which usually gets its whole supply from the femoral (anterior crural) nerve, and the adductor magnus, which gets a part of its supply from the sciatic nerve.
In embryonic development the pectineus arises in close conjunction with the obturator group, and in the adult it may get the wliole or a part of its nerve-supply from the obturator nerve or from the accessory obturator nerve. In the lower mammals the nerve-supply may come from the femoral (anterior crural) or the obturator nerve or from both. It is not certain whether the innervation from the femoral nerve indicates that the muscle belongs phylogenetically, if not ontogenetically, with the primitive dorsal musculature of the limb. By some it is considered to be derived in part from the primitive dorsal, in part from the primitive ventral, musculature. The adductor magnus arises in the embryo as two distinct portions, one connected with the flexor group of muscles, the other with the adductor group. These two portions later become fused. Primitively the sciatic portion of the adductor magnus and the semimembranosus constitute a single medial flexor muscle.
inferior ramus of the pubis and the pubic extremity of the inferior ramus of the ischium.
Structure and insertion. — The nearly parallel fibre-bundles which arise between two laminse of the tendon form a thin band of muscle which is narrower and thicker distaUy than proximally. They are inserted on a tendon which begins as an aponeurosis on the posterior border and medial surface of the muscle in the distal third of the thigh, becomes free as a rounded cord a little proximal to the medial condyle of the femur, runs behind the condyle, and then turns forward to be inserted by an expanded process into the tibia below the medial condyle.
With the knee flexed, it acts as a medial rotator of the leg.
Relations. — It occupies a position beneath the fascia lata and superficial to the adductor brevis, longus, and magnus muscles. DistaUy the sartorius lies in front, the semimembranosus behind. Its tendon crosses the tibial collateral Ugament of the knee-joint and the tendons of the semitendinosus and the semimembranosus, and is overlapped by that of the sartorius.
Variations. — The pubic Origin of the muscle may be much reduced or may be double. Its tendon of insertion may give rise to an accessory fasciculus which extends distaUy in the leg. In some of the apes the tendon descends normally much farther down the leg than in man.
The pectineus (fig. 411.) — Origin. — (1) From the peoten (crest) of the os pubis, the bone in front of this, and the pectineal fascia near this origin; and (2) from the anterior margin of the obturator sulcus and from the pubo-capsular hgament. Laterally the two areas of origin are usually separated by most of the superior surface of the body of the pubis. Medially _they come together.
Structure and insertion. — From each area of origin a separate lamina arises. The fibrebundles of each layer take a nearly parallel course and terminate between two tendinous lameUfe which fuse to be inserted into the upper half of the pectineal line behind the small trochanter. The fibre-bundles of the superficial layer cross those of the deep slightly obliquely. The muscle faces ventraUy at its origin, laterally at its insertion.
Nerve-supply. — From a branch of the femoral (anterior crural) nerve, which passes behind the femoral artery and vein and through the pectineal fascia to enter the ventral surface of the muscle. It may also be supplied by the accessory obturator nerve, when present, or by a branch from the obturator. When both the femoral (anterior crura!) and obturator nerves supply this muscle, the femoral supphes the superficial, the obturator, the deep lamina (Paterson).
Relations. — It is covered by the pectineal fascia, lies between the ilio-psoas and the adductor longus muscles, and crosses the obturator externus and adductor brevis muscles. The medial circumflex artery runs between it and the ilio-psoas, the deep femoral artery between it and the adductor longus.
Variations. — The extent of the division of the pectineus into superficial and deep portions varies considerably. It may also be divided into a lateral and a medial division. Often the pectineus is fused with the adductor longus. It may receive an accessory fasciculus from the capsule of the hip-joint, the iliacus muscle, the obturator externus, or the adductor brevis muscles, or the small trochanter. It may send a fasciculus to the sartorius.
of the pubis by a strong tendon which extends for some distance on the medial border of the Structure and insertion. — From this tendon the fibre-bundles diverge toward then- insertion. Fig. 413. — Superficial Muscles op the Back of the Thigh and Leg.
This takes place between two lamellae of a short tendon attached to the middle third of the linea aspera. The tendon is usually fused to the medial intermuscular septum and sends an expansion to the long tendon of the adductor magnus.
Nerve-supply. — A branch from the anterior division of the main obturator trunk gives off several twigs which enter the middle third of the deep surface of the muscle. Occasionally a small branch from the femoral (anterior crural) nerve enters the muscle. This is probably sensory in nature.
Relations. — The sartorius, the vastus medialis, and the femoral vessels he antero-lateral to it. Behind it lie the adductor brevis and adductor magnus muscles. Between these and the longus run the profunda vessels. Its lateral border touches the pectineus above, but is separated from it toward the insertion.
tendon.
Structure and insertion. — From their origin the fibre-bundles diverge into a sheet which is inserted by short tendinous bands into the distal two-thirds of the pectineal line and the upper third of the hnea aspera. The muscle is more or less completely divided into two fasoiouU near its insertion. The place of division is near where the intertrochanteric fine curves away from the linea aspera.
thigh.
Relations. — In front he the pectineus and adductor longus; behind, the obturator externus quadratus femoris and adductor magnus. It is crossed by the profunda artery. The first perforating artery passes usually between the two fasciouh of the insertion.
pletely into two fasciculi, rarely into three.
The adductor magnus (figs. 409, 412). — The origin of this muscle begins on the inferior ramus of the pubis posterior to the origins of the adductor brevis and gracilis muscles. From here it extends backward along the inferior margin of the ventro-lateral surface of the ischium to the tuberosity. The muscle in passing from this curved origin to its extensive femoral insertion presents posteriorly a longitudinal groove in which rest the hamstring muscles. The adductor magnus is composed of three superimposed fasciculi, of which the first is frequently fairly distinct and is called the'.adductor minimus, while the other two are normally fused, but are occasionally distinct.
The superior fasciculus (adductor minimus) arises directly from the inferior rami of the pubis and ischium. From here the fibres diverge to form a thin sheet inserted by tendinous bands to the medial side of the gluteal ridge and the superior part of the hnea aspera. The middle fasciculus arises dii'ectly from the inferior margin of the ventro-lateral surface of the inferior ramus and the tuber of the ischium, and from a tendon which descends along the dorsomedial margin of the muscle from the tuber ischti. The fibre-bundles diverge to be inserted between the lamellae of a narrow flat tendon attached to the distal three-fourths of the linea aspera. This tendon is pierced by the perforating vessels. The inferior fasciculus arises dorsal to and in common with the middle fasciculus. The fibre-bundles converge toward a strong tendon which begins in the distal third of the -thigh and is'inserted into a tubercle at the distal end of the medial supracondylar ridge.
Nerve-supply. — The chief nerve-supply is from the posterior ramus of the obturator. This enters by one or more branches the proximal portion of the ventral surface of the muscle about midway between its pubic and femoral attachments. It also receives a branch from the sciatic which enters the dorsal surface of the muscle in the middle third of the thigh. To the adductor minimus a branch may be sent from the nerve to the quadratus femoris.
Action. — It is the strongest of the adductors. The superior and middle fasciculi rotate the thigh medialward and flex it; the inferior rotate it lateralward when the thigh is extended, but medialward when the thigh is flexed. The latter also extend the thigh.
Relations. — In front are the pectineus, the short and long adductor and the vastus medialis muscles, and the profunda artery. Behind lie the hamstring muscles and the gluteus maximus. Medially lies the gracilis muscle. The femoral and perforating arteries pass through its attachment to the shaft of the femur.
Variations. — The divisions of the muscle may be more or less distinct. It may be partly fused or exchange fasciculi with neighbouring muscles — the semimembranosus, quadratus femoris, adductor brevis, and adductor longus.
B. m. pectinei. — A small bursa frequently present between this muscle and the iUo-psoas and small trochanter. B. anserina. — A fairly large bursa which lies between the tendons of the sartorius, gracUis, and semitendinosus muscles and the tibial collateral hgament of the kneejoint. (See also B. M. Sartorii Propria, p. 471.)
HAMSTRING GROUP 475
and semimembranosus rotate the thigh and the leg medialward; the biceps, lateralward. The semitendinosus and the long head of the biceps constitute a superficial layer; the semimembranosus and the short head of the biceps a deep layer. The semitendinosus and the long head of the biceps arise by a common tendon from the tuber of the ischium. The somewhat fusiform semitendinosus gives rise to a tendon in the lower half of the thigh. The tendon curves forward behind the knee to be inserted under that of the sartorius into the medial side of the tibia. The penniform short head of the biceps arises from the linea aspera in the lower part of the thigh, and is inserted, together with the fusiform long head, into a tendon that passes over the lateral side of the knee and is attached to the head of the fibula. The semimembranosus arises from the tuber ischii through a long, flat, triangular tendon. The belly of the muscle increases in thickness toward the knee. It is inserted by a strong tendon on the back of the medial condyle of the tibia. From the tendons of all the hamstring muscles expansions are sent into the crural fascia.
except the short head of the biceps, which is suppUed from the peroneal portion.
The femoral head of the biceps is characteristic of the anthropoid apes and man. In manymammals its place is taken by a slender muscle, the tenuissimus, which extends from the caudal vertebraj, the sacro-tuberous (great sacro-sciatic) ligament, or the gluteal fascia to the fascia of the back of the leg. In some forms this muscle is broad instead of slender. According to Testut, the long head of the biceps may be looked upon as arising by two fasciculi, one primitively attached to the posterior part of the ihum, the other to the caudal vertebrse or coccyx. The sacro-tulserous (great sacro-sciatic) ligament represents the reduced upper portion of this muscle. In the foetus the origin of the muscle extends higher on the sacro-tuberous Ugament than in the adult. In many of the lower mammals the origins of the semimembranosus and semitendinosus take place in part from the sacro-caudal vertebras.
In the mammals below man the insertion of the biceps, gracilis, and semitendinosus takes place chiefly into the fascia of the back of the leg, and extends more distally than in man. This insertion of these flexor muscles is associated with a permanent position of flexion of the leg at the knee. In the human embryo likewise these muscles are inserted more distally than in the adult. In the lower primates the semimembranosus is chiefly a medial rotator of the leg.
Biceps femoris (Figs. 408, 413). — Long head. — Origin. — From a tendon common to it and the semitendinosus. This tendon arises from the more medial of the two facets on the back of the tuber of the ischium and from the sacro-tuberous (great sacro-sciatic) ligament. It is continued for a third of the distance to the knee as a septum between the biceps and the semitendinosus, and for a short distance as. an aponeurotic sheath on the deep surface of the biceps.
Structure and insertion. — The fibre-bundles begin to arise from the tendon some distance from the ischium. They form a thick fusiform belly which is inserted into the deep surface of a tendon that begins laterally on the back of the muscle about the middle of the thigh. The insertion of the fibre-bundles of the long head continues on the medial margin of the deep surface of the tendon nearly as far as the lateral condyle of the femur.
Short head. — Origin. — By short tendinous fibres from the lateral lip of the linea aspera of the femur from the middle of the shaft to the bifurcation of this line, the proximal two-thirds of the supracondylar ridge, and the lateral intermuscular septum.
Structure and insertion. — ^The fibre-bundles take a nearly parallel course, to be inserted on the deep surface of the common tendon of insertion. The most distal fibres are inserted nearly to the skeletal attachment of the tendon. The tendon is inserted into the superior extremity of the head of the fibula, into the lateral condyle of the tibia, and into the fascia of the leg.
Nerve-supply. — Commonly two branches are given to the long head of the biceps. One of these branches is given off proximal to the ischium, and enters the 'proximal third of the deep surface of the muscle. The other is given off more distally and usually enters the middle third. Either or both branches may be doubled or the two may be combined for some distance in a common trunk. The nerve-fibres arise usually from the first, second, and third sacral nerves. The branch to the short head arises from the peroneal (external pophteal) portion of the sciatic nerve about the middle of the thigh. It enters the posterior surface near the lateral margin of the muscle, and passes distaUy across the muscle bundles about midway between the tendons of origin and insertion. The nerve-fibres come chiefly from the fifth lumbar, first and second sacral nerves.
leg. The long head acts as a lateral rotator of the thigh, and of the leg when flexed.
Relations. — The upper extremity of the muscle is covered by the gluteus maximus. Below this the long head and tendon of insertion lie beneath the fascia lata and overhe the short head. Ventral to the muscle lie the tendon of origin of the semimembranosus, the adductor magnus and vastus lateralis muscles, and the lateral head of the gastrocnemius. The medial border is in contact with the semitendinosus and semimembranosus. Distally it forms the upper lateral border of the pophteal space. The sciatic nerve runs between it and the adductor magnus.
Variations. — The short head is rarely absent. It may be more isolated from the long head than usual, and at times has a separate tendon of insertion. It may itself be divided into two distinct laminae. Its origin may take place higher up on the femur than usual or from the fascia lata. Variations of this sort suggest the tenuissimus muscle of some of the lower mammals
(see above). The long head of the biceps may receive accessory fasciculi from the coccyx, sacrum, sacro-tuberous (great sacro-sciatic) ligament, tuber of the ischium, or the deep surface of the gluteus maximus. These fasciculi suggest the iliac and sacro-coccygeal origin of the muscle found in lower vertebrates (see above). Inferiorly, a muscle fasciculus may take the place of the fibrous prolongations from the tendon of the biceps into the sural fascia (the tensores fasciae suralis). This may extend to the tendon of Achilles. The long head may have a tendinous inscription similar to that of the semitendinosus.
The semitendinosus (figs. 408, 413). — Origin. — Partly from a medio-dorsal facet on the distal margin of the tuber of the ischium by direct implantation of the fibre-bundles, and partly from the medial surface of the tendon common to it and the long head of the biceps.
Structure and insertion. — The fibre-bundles spread out to form a flat, fusiform belly which, about the middle of the thigh, again contracts toward the tendon of insertion. This begins on the medial margin and dorsal surface of the muscle, becomes free from the muscle slightly above the medial condyle of the femur, passes behind this and curves forward to be inserted by a triangular expansion into the proximal part of the medial surface of the tibia behind and distal to the insertion of the gracilis. An aponeurotic expansion is continued into the fascia of the leg. About the middle of the muscle a narrow irregular tendinous inscription more or less completely divides the belly into proximal and distal divisions.
Nerve-supply. — To the muscle two nerves are commonly given. One arises from the sciatic nerve or directly from the plexus, proximal to the tuber of the ischium, sometimes in company with a branch to the long head of the biceps. It enters the middle third of the deep surface of the proximal portion of the muscle. The other branch arises from the sciatic nerve, usually distal to the ischial tuber, sometimes in common with a nerve to the biceps or the semimembranosus. It enters about the middle of the deep surface of the distal half of the muscle. Either or both branches may be represented by two nerves. The nerve fibres of the first branch arise chiefly from the first and second sacral nerves, those of the second from the fifth lumbar and first sacral nerves.
Variations. — It may be completely separated from the biceps at its origin. It may be fused with neighbom'ing muscles. There may be two tendinous inscriptions. It may have a femoral head (a condition characteristic of many birds). A muscle fasciculus may extend from the body of the muscle to the fascia of the back of the leg.
The semimembranosus (fig. 408). — Origin. — By a long, flat tendon which lies beneath the proximal half of the semitendinosus, and which arises from the more lateral of the two facets on the back of the tuber of the ischium, between the tendons of the biceps and the quadratus femoris. The tendon is at first adherent to the tendon of the adductor magnus in front and to that of the biceps and semitendinosus behind. It descends to the middle of the muscle.
Structure and insertion. — From both surfaces of the medial side and distal extremity of the tendon of origin fibre-bundles arise which take an oblique course to their insertion on the aponeurosis of the tendon of insertion. This appears on the deep surface and medial margin of the muscle opposite the end of the tendon of origin and descends on the medial side and deep surface of the muscle. Near the back of the medial condyle of the femur the insertion of musclefibres ceases and the tendon is inserted directly on the back of the medial condyle of the tibia, and by aponeurotic expansions into the capsule of the joint, into the lateral condyle of the femur, into the tibial collateral ligament, and into the fascia of the pophteus muscle.
Nerve-supply. — By several branches from the sciatic nerve, which usually arise from a common trunk in company with the branches to the adductor magnus. These branches enter the deep surface of the muscle about midway between the origin and insertion of the constituent fibre-bundles.
Variations. — It may be fused with the semitendinosus or the adductor magnus. It may be doubled. Its tendons may have a more extensive attachment than usual. The extent of the belly of the muscle varies con.siderably. A muscle fasciculus may be sent into the popUteal space. An extra head may arise from the ischial spine.
B. m. bicipitis femoris superior. — A fair-sized bursa which frequently lies between the tendon of origin of the long head of the biceps and semitendinosus and the tendon of the semimembranosus and the ischial tuber. B. m. bicipitis femoris inferior. — A small bursa which separates the tendon of insertion from the fibular collateral ligament of the knee-joint. B. m. bicipitis gastrocnemialis. — A bm-sa infrequently found between the tendon of the biceps and the tendons of origin of the lateral head of the gastrocnemius and the plantaris muscles. B. m. semimembranosus. — This is a large double bursa constantly present. One part extends between the semimembranosus, the medial head of the gastrocnemius, and the knee-joint. With the cavity of the joint it frequently communicates. The other part extends between the tendon of the semimembranosus and the medial condyle of the tibia.
The musculature of the leg arises in part from the distal end of the femur, but in the main from the tibia and fibula. The muscle-bellies are best developed in the proximal half of the leg, where they give rise to the ' calf behind and to less well-marked ventral and lateral protrusions. Toward the ankle the musclebellies give way to tendons which attach the muscles of the leg to the skeleton of the foot.
The musculature is divisible into an anterior, a lateral and a posterior group of muscles. The anterior and lateral groups are separated from one another by an intermuscular septum. The antero-lateral groups are separated from the posterior group by the tibia and fibula, the interosseous membrane, and by an intermuscular septum which extends from the lateral margin of the shaft of the fibula to the fascia enveloping the leg. Medially the separation is well marked by the broad medial surface of the tibia. Laterally the line of division is not so clearly marked externally. In the proximal part of the leg the dorsal musculature protrudes somewhat ventrally; in the distal part the lateral musculature passes dorsal to the lower end of the fibula. The posterior group is divided by a transverse septum into superficial and deep divisions.
While in the forearm the extensor-supinator muscles extend proximally on the radial side of the arm to the humerus, and the flexor-pronator muscles on the ulnar side, in the leg both of the corresponding sets of muscles extend primitively on the fibular side of the leg to the femur. In the higher vertebrates the superficial layer of the flexor musculature of the leg takes origin from both sides of the distal extremity of the femur, and the origin of the extensor musculature ceases to extend to the femur. The crural musculatiu'e is primitively inserted into the bones of the leg, the tarsus, and the aponeuroses of the foot. On the extensor side of the leg the musculature ultimately becomes attached wholly to the foot by means of tendons differentiated, in part at least, from the dorsal aponeurosis. The lateral portion of the extensor musculature, which primitively extends from the femur to the fibula, in the higher vertebrates extends from the fibula to the tarsus and metatarsus (peroneal musculature). On the flexor side of the leg the more superficial musculature maintains a tarsal attachment through the tendon of Achilles. The deeper musculature in part extends from the femur and fibula to the tibia, in part arises from the fibula and tibia, and is inserted into the metatarsus and the digits through tendons differentiated from the plantar aponeuroses. The musculature of the sole of the foot is highly developed in five-toed vertebrates, but in those which walk on the toes, and especially in hoofed animals, it is very greatly reduced.
FASCIiE OF THE LEG
The tela subcutanea of the leg contains a considerable amount of fat where it overlies the muscles, but less where it overhes the bones and joints. Subcutaneous bursas are found over the tuberosity of the tibia (b. subcutanea tuberositatis tibiae) and over each of the malleoU (b. subcutanea malleoli medialis et lateralis). Over the dorsum of the foot the tela contains comparatively little fat, but on the sole of the foot and plantar surface of the toes it contains much fat interposed between dense fibrous tissue. The b. subcutanea calcanea hes beneath the tuber calcanei.
The crural fascia, or external layer of fascia of the leg, extends from the knee to the ankle. It forms an enveloping cone-Hke sheath for the muscles and is adherent to the periosteum of the medial surface of the tibia. It is formed of transverse, oblique, and longitudinal fibres and is thickest in front.
Ventrally the fascia of the thigh, to which the tendons of the quadriceps, sartorius, graciUs, semitendinosus, and biceps muscles and the ilio-tibial band are closely united, becomes attached with these tendons to the tibia and fibula. From these attachments, therefore, the fascia of the front of the leg may be said to arise. Into it extend processes from the tendons mentioned. DorsaUy the fascia of the thigh is continued uninterruptedly into that of the leg. Distally the crural fascia is attached to the two malleoli and to the posterior surface of the calcaneus.
From the fascia two main intermuscular septa arise. One, the anterior intermuscular septum, extends between the extensor digitorum longus and peroneal muscles to the anterior crest of the fibula; the other, the posterior intermuscular septum, between the peroneal muscles and the soleus to the lateral crest of the fibula. These septa separate compartments for the anterior, lateral, and posterior groups of muscles.
1. Arteria peronea. 2. A. pophtea. 3. A. tibialis anterior. 4. A. tibialis posterior. 5 Bursa anserina. 6. Bursa m. sartorii propria. 7. Fascia cruralis. 8. Fibula. 9 Ligamentum crurale transversum. 10. Lig. patellse. 11. Membrana interossea. 12 Musculus biceps femoris — tendon. 13. M. e.xtensor digitorum longus — a, tendon. 14. M extensor hallucis longus. 15. M. flexor digitorum longus. 16. M. flexor hallucis longus 17. M. gastrocnemius — a, lateral head; b, medial head. 18. M. graciUs, tendon. 19 M. peroneus brevis. 20. M. peroneus longus — a, tendon. 21. M. peroneus tertius, 22. M. plantaris — a, tendon. 23. M. pophteus. 24. M. sartorius, tendon. 25. M I semimembranosus, tendon. 26. M. semitendinosus, tendon. 27. M. soleus — a, fasciculus accessorius. 28. M. tibialis anterior — a, tendon. 29. M. tibialis posterior — a, tendon. 30. N. cutaneus surse lateralis. 31. N. cutaneus surse medialis. 32. N. peroneus communis (external pophteal). 33. N. peroneus profundus (anterior tibial). 34. N. peroneus superficiales (musculo-cutaneus) . 35. N. plantaris laterahs (external plantar). 36. N. plantaris medialis (internal plantar). 37. N. suralis (external saphenous). 38. N. tibialis (posterior tibial). 39. Septum intermusculare (anterior). 40. S. intermusculare (posterior). 41. S. surse transversum. 42. Tendo Achilhs (calcanei). 43. Tibia. 44. Vena saphena magna. 45. V. saphena parva.
I The semimembranosus has a special fascial investment which, on the back of the_knee becomes bound on each side of the muscle and its tendon to the capsule of the joint. This fascia extends into a transverse septal membrane which is continued over the deep muscles of the back of the leg to the ankle. It is united on one side to the tibia, on the other to the fibula. Proximally the fibres are continued into it from the tendon of the semimembranosus. Over the back of the tibia the septum is interrupted by the attachment of the soleus to the pophteal line. Beyond the tibial origin of the soleus it is fused on the medial side of the flexor digitorum longus to the crural fascia.
The transverse crural ligament (upper part of anterior annular ligament) (fig. 415) lies on the front of the lower part of the leg above the ankle. It is composed of fascia strengthened by transverse bundles which pass from the medial side of the tibia to the ventral margin of the fibula. From its deep surface a strong, broad septum descends to the tibia and divides the underlying space into two osteo-fibrous canals, a medial for the tibialis anterior and a lateral for the long extensor muscles. The lateral compartment is further subdivided by a sUghtly marked septum into a medial division for the extensor hallucis longus and a lateral for the extensor digitorum longus and the peroneus tertius.
The cruciate ligament (lower part of anterior annular ligament) (fig. 415) serves to hold the tendons of the anterior muscle group in place as they pass to the dorsum of the foot. In part it is formed by a dense fibrous band lying in the fascia over the ankle, in part of a ligament which passes from the bones of the ankle to the deep surface of this band. The superficial band is V-shaped. It arises from the lateral surface of the body of the calcaneus and passes across the dorsum of the foot, one arm of the V going to the medial malleolus, the other to the side of the foot, where it terminates in the fascia over the first cuneiform bone. The apex of the V lies over the tendons of the extensor digitorum longus and peroneus tertius muscles. The distal arm extends over the tendons of the extensor hallucis longus and tibialis anterior
muscles. The proximal arm passes over the tendon of the extensor hallucis longus and then divides into two layers, between which the tendon of the tibialis anterior passes. The deeper ligament mentioned above arises from deep within the tarsal sinus, some of its fibres even from the sustentaculum tali. It then passes forward and medially beneath the long extensor tendons, and divides into two parts, one of which curves about the medial margin of the tendon of the extensor digitorum longus, the other about the extensor hallucis longus tendon to the under surface of the proximal arm of the V-shaped band.
The peroneal retinacula are strengthened regions in the fascia which serve to hold the tendons of the peroneal muscles in place. The superior extends from the lateral malleolus into the fascia on the back of the leg, and to the lateral surface of the calcaneus. The inferior overlies the tendons on the lateral surface of the calcaneus, and is attached to this bone on each side of them. Between the tendons it sends a septum to the bone. It is connected with the superficial layer of the cruciate ligament.
The laciniate ligament (internal annular) (fig. 416) is found on the medial side of the ankle. Here the fascia is strengthened by fibre-bands which form a well-marked ligament that holds in place the tendons of the deep dorsal cruro-pedal muscles. This ligament extends from the dorsal and distal margins of the medial malleolus to the calcaneus. It is closely bound to the tibia and the talo-tibial (tibio-astragaloid) ligament until the tendon of the tibialis posterior is reached. It passes over this and becomes bound to the bony structures on the posterior margin of the tendon. From tjiis attachment two layers, a deep and a superficial, extend backward. The superficial layer extends to the tuber calcanei, and is connected superiorly with the crural fascia. The deep layer, which represents a continuation distally of the transverse septum, extends over the tendons of the flexor digitorum longus and flexor hallucis longus to the medial surface of the calcaneus, and is closely united to the underlying bone on each side of these tendons, thus giving rise to osteo-fibrous canals.
The anterior musculature of the leg consists of four muscles, the tibialis anterior, extensor digitorum longus, peroneus tertius, and extensor hallucis longus. The tibialis anterior has a quadrangular prismatic belly which arises from the lateral side of the tibia and adjacent interosseous membrane in the proximal half of the leg. The tendon passes over the front of the tibia to the first metatarsal. The extensor digitorum longus is a transversely flattened, fusiform muscle, which arises from the superior extremity of the tibia, the anterior crest of the fibula, and the adjacent interosseous membrane, and gives rise to a tendon which passes over the front of the distal extremity of the tibia and sends tendons to the two terminal phalanges of the four more lateral toes. The peroneus tertius represents a more or less completely differentiated portion of the preceding muscle. Its tendon passes laterally through the same osteofibrous canal in the same synovial sheath and terminates on the fifth metatarsal. The extensor hallucis longus is a narrow muscle which arises from the distal half of the medial surface of the fibula and the interosseous membrane. Its tendon extends over the ankle to the great toe. The tendons of these muscles are held in place by the transverse and cruciate ligaments described above.
All the muscles of this group flex the foot. The extensors extend the toes; the peroneus tertius and the extensor digitorum longus evert the foot. The nerve supply is from the deep peroneal (anterior tibial) nerve.
The tibialis anterior is represented in the arm probably by the braohio-radialis and the two radial extensors; the extensor digitorum longus by the extensor digitorum communis and extensor digiti quinti proprius; and the extensor hallucis longus by the extensor poUicis longus. Two abnormal muscles not infrequently found, the abductor hallucis longus and extensor primi internodii hallucis, represent probably the corresponding normal muscles of the hand.
The tibialis anterior (fig. 415). — Origin. — From the distal surface of the lateral condyle of the tibia, and the lateral surface of the proximal half of the shaft of the tibia, the adjacent interosseous membrane, the overlying fascia near the condyle (tuberosity) of the tibia, and the intermuscular septum between it and the extensor digitorum longus.
Structure. — Bipenniform. The fibre-bundles converge upon a flat tendon which begins high in the muscle and emerges on the anterior margin of the muscle about the middle of the leg. On the deep surface the implantation of fibre-bundles continues to the transverse crural (anterior annular) ligament.
metatarsal.
Nerve-supply. — As a rule, a branch from the common peroneal (external popUteal) nerve enters the proximal portion of the muscle by several twigs, and another from the deep peroneal (anterior tibial) enters near the middle of the belly on the lateral edge.
Relations. — In the proximal half of the leg the extensor digitorum longus hes lateral to it; and between the two muscles, the anterior tibial artery and vein. It is covered by the crural fascia and rests on the interosseous membrane. Distally it lies over the extensor hallueis longus. The tendon passes in special compartments beneath the transverse and the cruciate (anterior annular) hgaments.
f^' u^^*^°^°^ digitorum longus (fig. 4:1 5). —Grig 171. —From the lateral condyle of the tibia, the anterior crest (surface) of the fibula, the intermuscular membrane between it and the tibiahs anterior, the lateral margin of the interosseous membrane, the septum between it and the peroneus longus, and the fascia of the leg near the tibial origin.
ankle. Usually at the distal margin of the transverse (anterior annular) Hgament the tendon divides into two parts which pass between the two layers of the cruciate (lower part of anterior annular) ligament, and then each divides again into two parts, thus giving rise to four slips, one for each of the four lateral toes.
Insertion. — Each tendon on the dorsal surface of the toe to which it goes divides into three fasciculi: an intermediate, which is attached to the dorsum of the base of the second phalanx; and two lateral, which converge to the dorsum of the base of the third phalanx. The margins of the tendon are also bound by fibrous tissue to the sides of the back of the first phalanx.
the deep surface of the muscle, one near its tibial origin, one about the centre of the belly.
Relations. — In the proximal half of the leg it lies on the interosseous membrane, and beneath the fascia of the leg, and adjoins medially the tibialis anterior, laterally the peroneus longus. DistaUy it lies over the extensor hallucis longus and adjoins laterally the peroneus brevis. The tendon passes beneath the transverse crural and the superficial layer of the cruciate (anterior annular) ligaments and over the extensor digitorum brevis muscle. The superficial peroneal (musculo-cutaneous) nerve runs in the septum between it and the peroneal muscles; the anterior tibial artery and deep peroneal nerve pass beneath the head of the muscle, and then between it and the tibialis anterior.
of the fibula, the neighbouring interosseous membrane, and the anterior intermuscular septum.
Structure. — It is essentially a fasciculus of the extensor digitorum longus, from which it is seldom completely differentiated. The fibre-bundles descend obliquely forward to be inserted In a penniform manner on a tendon which runs along the lateral margin of the tendons of the extensor digitorum. The attachment of fibre-bundles continues to the cruciate ligament (lower part of anterior annular ligament).
Relations. — It lies lateral to the extensor digitorum longus. Its tendon passes into the foot beneath the transverse crural and the superficial layer of the cruciate hgament in the same compartments with those of the extensor longus.
phalanx the margins of the tendon are attached to the bone by bands of fibres.
Nerve-supply. — As a rule, a branch from the deep peroneal (anterior tibial) nerve enters the deep surface of the muscle near the junction of the upper and middle thirds, and passes distally across the middle of the obliquely running muscle fibre-bundles.
Relations. — It lies on the distal half of the interosseous membrane, partly covered by the extensor digitorum longus and the tibiaUs anterior muscles. Its tendon passes over the front of the distal extremity of the tibia and the medial side of the dorsum of the foot and is held in place by the transverse and cruciate ligaments and by a strengthening band in the fascia over the base of the first metatarsal. In the distal part of the leg the anterior tibial artery and the deep peroneal (anterior tibial) nerve pass beneath the muscle to enter the foot on the lateral side of its tendon.
Actions. — The muscles of this group all flex the ankle. The tibiahs anterior and extensor hallucis longus evert the foot at the talo-calcaneo-navicular joints, and invert it at the talonavicular, calcaneo-cuboid joints. In certain positions the tibialis anterior may, however, invert the foot at these joints. The peroneus tertius and the long extensor evert the foot. The force of the extensor hallucis longus is exerted powerfully on the first phalanx and weakly on the second. The short muscles of the big toe aid in extending the second phalanx. The extensor digitorum longus extends the first phalanx of each toe powerfully, but exerts less force on the second and third. The lumbrical muscles assist in extending the last two phalanges.
Variations. — The origin of the tibialis anterior may extend to the femur. Its tendon of insertion may give accessory slips to the cuneiforms, metatarsals, and phalanges. ^ More rarely its belly is divided into two portions, one of which sends a tendon to the first cuneiform and one to the first metatarsal. A slip, the tensor fascise dorsalis pedis (Wood), may pass to the dorsal fascia of the foot. Another, the tibio -astragalus anticus (Gruber), to the talus (astragalus) or calcaneus. The bellies or the tendons of the extensor hallucis and extensor digitorum may be more or less completely fused, or tendon slips may pass from the tendon of one muscle to that of the other. Tendon slips may pass to the metatarsal bones or from the tendon of one toe to that of a neighbouring toe. The tendon to each toe may be doubled. The belly of the extensor digitorum longus may be more or less completely subdivided to correspond with the tendons to individual toes. The peroneus tertius is frequently fused with the long extensor. It may be doubled. More often its tendon may bifurcate or trifurcate and be inserted into the extensor tendons of the fifth toe or into the fourth or third metatarsal. It is absent in about 8.5 per cent, of bodies (Le Double).
Abnormal Muscles. — The abductor hallucis longus is rarely found as a completely independent muscle. It usually arises as a fasciculus of the e.xtensor digitorum longus, extensor hallucis longus, or the tibialis anterior. It is inserted into the base of the first metatarsal. The extensor primi internodii hallucis (extensor hallucis brevis) has an origin similar to that of the long abductor above described. It is inserted into the dorsum of the base of the first phalanx of the big toe. It is not to be confounded with that portion of the extensor digitorum brevis connected with the great toe and also sometimes called the extensor hallucis brevis.
BnRSiE
B. subtendinea m. tibialis anterioris. — A small bursa between the medial surface of the first cuneiform bone and the tendon of the tibialis anterior. B. subtendinea m. extensoris hallucis longi. — A small bursa beneath the tendon near the tarso-metatarsal articulation. It may communicate with the synovial sheath of the tendon. B. sinus tarsi. — A large bursa in the sinus tarsi and on the lateral surface of the neck of the talus (astragalus) beneath the tendons of the extensor digitorum longus and the fibrous bands between the talo-calcaneal and the cruciate ligaments. It extends back to the talo-crural, forward to the talo-navioular joint, and may communicate with the joint cavity of the latter.
Vagina tendinis m. tibialis anterioris. — This sheath surrounds the tendon from above the transverse crural ligament to the talo-navicular joint. Vagina tendinis m. extensoris hallucis longi. — The sheath begins above the proximal arm of the cruciate ligament, and ends near the tarso-metatarsal joint beneath a band-Uke thickening of the dorsal fascia of the foot. Vagina tendinum m. extensoris digitorum longi. — This sheath surrounds the tendons of the long digital extensor and the peroneus tertius from above the cruciate ligament to the middle of the third cuneiform bone.
The lateral muscles consist of the peroneus longus and the peroneus brevis. They extend and evert the foot. The thick prismatic belly of the peroneus longus arises from the proximal half of the lateral surface of the fibula and from neighbouring structures, while the smaller belly of the peroneus brevis arises from the middle third of the lateral surface of this bone. The peroneus longus partly covers the peroneus brevis. The tendons of the two muscles pass behind the lateral malleolus, held in place by special retinacula (p. 480). There the tendon of the peroneus longus lies at first lateral to and then crosses behind that of the peroneus brevis and curves about the lateral side of the calcaneus and across the sole of the foot closely applied to the cuboid and to the tarso-metatarsal articulations, and terminates on the base of the first metatarsal. The tendon of the peroneus brevis terminates on the lateral side of the foot at the base of the fifth metatarsal. The nerve supply is from the superficial peroneal (musculo-cutaneous) nerve.
The two muscles are probably represented in the arm by the extensor carpi ulnaris. In some of the lower animals the head of the peroneus longus extends to the femur. The fibular collateral ligament of the knee-joint probably represents in man the femoral head of the peroneus longus.
The peroneus longus (figs. 416, 422). — Origin. — Anterior head: tendinous from the anterior tibio-fibular ligament, the neighbouring part of the lateral condyle of the tibia, and the head of the fibula; fleshy from the proximal third of the anterior intermuscular septum and the crural fascia near the tibia. Posterior head : fleshy from the proximal half of the lateral surf ace^of the shaft of the fibula and from the posterior intermuscular septum.
Structure. — Bipenniform. The fibre-bundles converge upon a tendon which begins high in the muscle. The constituent fibre-bundles of the anterior head are long and take a nearly vertical course. The fibre-bundles of the posterior head take a more obhque course and their attachment extends more distally on the tendon. The tendon emerges on the surface of the muscle in the distal half of the leg. The fibre-bundles of the posterior head extend to within a few centimetres of the lateral malleolus. The tendon passes through the retro-malleolar groove, passes across the lateral face of the calcaneus, to and through the peroneal groove of the cuboid, and crosses the second and third tarso-metatarsal joints. Where the tendon enters the groove in the cuboid it contains a fibro-cartilaginous nodule which may become a sesamoid bone.
Insertion. — On the inferior surface of the first cuneiform and on the supero-lateral border and base of the first metatarsal. From the region of the fibro-cartilaginous nodule above mentioned a fibrous slip is usually sent to the base of the fifth metatarsal.
Nerve-supply. — Most commonly the peroneal (external pophteal) nerve before dividing gives off two branches. One of these enters the deep surface of the middle third of the anterior head, the other passes across the middle third of the constituent bundles of the posterior head. The latter branch may arise from the superficial peroneal (musculo-cutaneous) nerve, and it may extend to supply the peroneus brevis.
Structure. — Penniform. The fibre-bundles converge upon a tendon which begins high in the muscle and becomes visible on the lateral surface of the distal half of the belly. Behind the lateral malleolus the tendon becomes free, then passes forward below the malleolus and, across the calcaneus and cuboid.
Nerve-supply. — The nerve arises from the superficial peroneal (musculo-cutaneous) nerve, or from a branch to the peroneus longus. It enters the proximal margin of the muscle and passes distally across its constituent fibre-bundles.
Relations. — The peroneal muscles in the leg are contained in a compartment bounded by the anterior and posterior intermuscular septa, by the fibula, and by the fascia of the leg. The peroneus longus to a considerable degree overlies the peroneus brevis. Beneath the upper part of the peroneus longus the peroneal (external popliteal) nerve bifurcates into its two chief branches. The deep peroneal (anterior tibial) nerve passes medially beneath the anterior head of the muscle. The superficial peroneal (musculo-cutaneous) nerve extends in the interval between the areas of the attachment of the two heads of the peroneus longus, and along the anterior margin of the peroneus brevis to the anterior intermuscular septum, through which it passes to its superficial distribution. The tendon of the peroneus longus at first lies lateral to and slightly overlaps that of the peroneus brevis. Toward the tip of the malleolus it lies almost directly posterior to this tendon. On the lateral surface of the calcaneus the tendon of the brevis lies superior to that of the longus, from which it is separated by a bony spine, the processus trochlearis of the calcaneus. The tendon of the longus is separated from the deep surface of the abductor of the little toe, and is held in place in the groove in the cuboid by the long plantar ligament.
Variations. — The two peroneal muscles may be more or less fused. The origin of the peroneus longus may extend to the femur. The two heads of origin may be fused. Its tendon of insertion may send slips to the second, third, and rarely to the fourth and fifth metatarsals. The tendon may be united to that of the tibialis posterior (12 out of 45 bodies — Picou). Sesamoid cartilages or bones are occasionally found in the retro-malleolar and calcaneal portions of the tendon. The tendon of the peroneus brevis may send a slip to the second or third phalanx or to the head of the metatarsal of the fifth toe, to its extensor tendon, or to the cuboid. It may also send a fasciculus to the fourth metatarsal or the extensor tendon of the fourth toe.
Accessory peroneals. — Poirier considers these all varieties of a muscle which in its simplest form arises from the distal fourth of the fibula and is inserted by a tendon into the fifth toe. A corresponding muscle is normally found in many of the monkeys (peroneus digiti quinti). In man in one form or another it is a frequent anomaly. It may be so fused with the peroneus brevis that only its tendon of insertion is apparent. It may appear as a special muscle fasciculus of the peroneus longus or brevis. It may be merely a tendinous band, or it may be tendinous at origin and insertion, with an intermediate belly. Instead of being attached to the fifth toe, it may be inserted into the fifth metatarsal, the cuboid, the tendon of the peroneus longus, the calcaneus, lateral malleolus, or posterior talo-fibular hgament.
Vagina tendinum peroneorum communis. — There is a double sheath for the tendons of the peroneal muscles as they pass back of the lateral malleolus. From this region of union the sheath sends processes along each tendon proximally above the malleolus and distally over the lateral surface of the calcaneus. This process on the tendon of the peroneus longus often communicates with the following sheath. Vagina tendinis m. peronaei longi plantaris. — This sheath begins in the peroneal groove of the cuboid and ends near the medial border of the long plantar hgament.
To this group belong the gastrocnemius, soleus, and plantaris muscles. They extend the foot and flex the leg. The two ovoid heads of the gastrocnemius arise one on each side from above the condyles of the femur, extend about to the middle of the back of the leg, and are inserted into the posterior surface of the tendon of Achilles, and through this into the back of the calcaneus. The broad, flat, ovoid soleus arises beneath the gastrocnemius from the tibia and fibula, and is inserted into the deep surface of the tendon of Achilles as far as the ankle. The two heads of the gastrocnemius and the soleus constitute the triceps surag. The plantaris is a slender muscle which passes along the medial margin of the lateral head of the gastrocnemius and beneath the medial head, where it gives rise to a slender tendon that runs between the gastrocnemius and soleus and along the medial margin of the tendon of Achilles to the fatty fibrous tissue of the heel. The nerve-supply is from the tibial nerve.
The muscles of this group have a common embryonic origin, and are first differentiated on the fibular side of the leg, whence they extend over the posterior tibial vessels and nerve to their medial attachments. The gastrocnemius corresponds with the flexor carpi radialis and ulnaris, the plantaris with .the palmaris longus, the soleus with a portion of the flexor digitorum
more developed than in man.
The gastrocnemius (fig. 413). — Medial head. — Origin. — From a facet on the back of the medial condyle of the femur above the articular surface, from an area on the back of the femur superior and lateral to this, and from the femoral margin of the capsule of the knee-joint. Lateral head. — Origin. — From a facet on the proximal portion of the postero-lateral surface of the lateral condyle of the femur and from a rough area situated more medially and at a greater distance from the joint.
Structure and insertion. — The heads of the gastrocnemius are similar in structure. From the condylar facets there descend aponeurotic bands, one oh the medial margin and the medial side of the posterior surface of the medial head, the other on the lateral margin and the lateral side of the posterior surface of the lateral head. These bands descend about two-thirds of the way down the muscle. In the tendon of the lateral head a sesamoid bone is frequently found. The fibre-bundles of the muscle pass obhquely from the supracondylar areas of origin and from the deep surface of the aponeurosis on each side to the tendon of insertion. This tendon begins as a septum between the two heads, and as a lamina on the deep surface of each head. The septum and laminae soon fuse with the broad aponeurosis which covers the dorsal surface of the soleus. The attachment of fibre-bundles continues to about the middle of the back of the leg. The attachment of the medial head extends more distaUy than that of the lateral head. As a rule, the medial head is also the broader and thicker of the two.
The soleus. — Origin. — (1) By a fibular head from the back of the head and the proximal third of the posterior surface of the shaft of the fibula, and from the intermuscular septum between it and the peroneus longus; and (2) by a tibial head from the transverse septum over the distal margin of the pophteus, from the popliteal line, and from the middle third of the medial border of the tibia.
Structure and insertion.'- — From the fibular and tibial origins arise broad aponeuroses which unite proximally on the deep surface of the muscle so as to form a fibrous arch over the posterior tibial vessels and nerves. DistaUy they diverge and become more narrow, but the fibular aponeurosis is continued on the fibular side and the tibial aponeurosis on the tibial side of the muscle as far as the distal quarter of the leg. The main portion of the belly of the muscle is formed by fibre-bundles which arise from the posterior surface of these aponeuroses and pass obliquely to be inserted in a bipenniform manner on the deep surface of the tendon of Achilles. This tendon begins as a broad aponeurosis which covers the greater part of the posterior surface of the muscle, and gradually converges into a heavy fibrous band that is inserted into the calcaneus. The bundles of fibres of the tendon take a slightly spiral course. Those on the posterior surface run from the medial margin toward the lateral surface of the calcaneus; those on the anterior surface in a reverse direction. The attachment of the fibrebundles continues to within a short distance of the heel. A few of the fibre-bundles arise directly from the fibula and the posterior intermuscular septum. On the deep surface of the belly of the muscle there is an accessory fasciculus which is formed by fibre-bundles that spring on each side from the anterior surface of the aponeuroses of origin of the muscle and have a bipenniform insertion on each side of a thin, obUque tendinous lamina which inferiorly becomes united to the deep surface of the tendon of Achilles.
The plantaris (fig. 413). — This muscle arises from the distal part of the lateral line of bifurcation of the Unea aspera, in close association with the lateral head of the gastrocnemius. The fibre-bundles give rise to a flat, short, fusiform belly, and are united to a narrow tendon which extends along the medial edge of the tendon of Achilles to the lateral part of the dorsal surface of the calcaneus, where it terminates in the neighbouring fibrous tissue.
Nerve-supply. — From the tibial (internal pophteal) part of the sciatic nerve in the popliteal space nerves arise for each head of the gastrocnemius. Each nerve enters the middle third of the deep surface of the head near the proximal margin. The nerve-supply for the soleus is from two sources. One nerve arises in the pophteal space, often in company with the nerve to the lateral head of the gastrocnemius. It enters the posterior surface of the muscle near the proximal border and divides into two branches, one for each head of the muscle. The tibial (posterior tibial) nerve gives rise to a branch which, about half-way down the leg, enters the deep surface of the muscle and furnishes branches for the deep portion of the muscle on each side. The nerve-supply of the plantaris is by a branch from the tibial (internal popliteal) portion of the sciatic. This arises in the popliteal space and enters the deep surface of the muscle.
Relations. — The semimembranosus winds about the medial margin of the medial head of the gastrocnemius to its deep surface. The biceps passes to the lateral side of the lateral head of the gastrocnemius, and the plantaris along its mecUal margin. The semimembranosus and biceps above, the medial head of the gastrocnemius and the plantaris below, bound the ponUteal space. The peroneal (external popliteal) nerve passes from the popliteal space obliquely across the plantaris and the lateral head of the gastrocnemius. The medial sural (short saphenous) nerve and the small saphenous vein pass between the heads of the gastrocnemius to the surface and thence to the lateral side of the ankle. From the peroneal (external pophteal) nerve in the popliteal space the lateral sural (communicans peronei) nerve extends distaUy over the calf. The (posterior) tibial nerve and posterior tibial artery and vein run between the two heads of the gastrocnemius, and then beneath the soleus to the medial side of the ankle. In the region of the tendon of Achilles a considerable space filled with fatty tissue intervenes between the tendon and the transverse septum.
Action. — The contraction of the triceps surte produces extension, adduction, and inversion of the foot. The gastrocnemius is also a flexor of the leg. The plantaris has no known function in man. In some animals it is an extensor of the plantar fascia.
Variations. — There is considerable variation in the extent of the separation of the different parts of the triceps sura;. The tendons of the three heads may be separate nearly to the heel. Either or both heads of the gastrocnemius or the soleus may be doubled. A shp from the biceps
or semimembranosus, from the linea aspera, or popliteal space may join the triceps and give rise to a quadriceps surse. On the other hand, one of the heads of the gastrocnemius or the tibial head of the soleus may be missing. A supernumerary fasciculus may extend from the deep surface of the soleus to the calcaneus. The plantaris is exceedingly variable in origin, structure, and insertion. The origin may be from the capsule of the knee-joint, the fascia of the leg, or from the tibia. Its tendon may terminate at almost any part of its course in neighbouring structures. It may be represented by a fibrous band. It is absent in about 7 per cent, of instances (Le Double).
B. m. gastrocnemii lateralis. — A bursa is often found between the tendon of the lateral head of the gastrocnemius and the capsule of the joint. It may communicate with the joint cavity. B. m. gastrocnemii mediaUs. — A bursa usually hes between the tendon of origin of the medial head of the gastrocnemius, the condyle of the humerus, and the capsule of the joint. Another bursa (b. m. semimembranosi) extends between the semimembranosus and the medial head of the gastrocnemius muscle. The two bursaj frequently communicate with one another and with the joint. B. tendinis calcanei. — This lies between the tendon of AchiUes and the upper part of the back of the calcaneus. Between the back of the tendon and the crural fascia another bursa is frequently present.
h. Deep Group
The deep posterior musculature is separated from the superficial by the transverse septum described above (p. 479). The muscles covered by this septal fascia are the popliteus, the flexor digitorum longus, the flexor hallucis longus, and the tibialis posterior. An intermuscular septum between the popliteus and the tibialis posterior, and the attachment of the soleus to the popliteal line on the back of the tibia serve to separate the popliteus from the other deep posterior muscles which lie distal to this region and send tendons into the sole of the foot The deep posterior musculature may thus be considered as divided into a proximal femoro-tibial and a distal cruro-pedal group. Both sets of muscles are supplied by branches of the tibial nerve.
The popliteus (fig. 416). — A triangular muscle which arises from an ovoid facet at the inferior extremity of the groove on the outer side of the lateral condyle of the femur and is inserted into the proximal lip of the popliteal line of the tibia and the surface of the shaft of the tibia proximal to this. It rotates the leg medialward and flexes it.
Structure. — From the origin a broad tendon ghdes over the condyle within the capsule of the joint, then over the lateral fibro-cartilage and through a groove on the back of the tibio-fibular articulation. From both surfaces of this tendon, fibre-bundles diverge toward the area of insertion. The tendon is more or less intimately united to several structures with which it comes in contact about the joint. Rarely it contains a sesamoid bone. The fibres of insertion terminate in part in the fascia covering the muscle. The pophteus is homologous with the pronator teres of the arm, or, according to some investigators, with the deep portion of that muscle.
Nerve-supply. — -A nerve which arises either independently or in conjunction with that to the posterior tibial muscle enters the popliteus near the middle of its distal edge. Sometimes a branch from the chief nerve to the knee-joint enters the proximal edge of the muscle.
Relations. — The popliteus lies within a compartment bounded by the transverse septum, the capsules of the knee and superior tibio-fibular joints, the back of the tibia, and a septum extending to the pophteal line (see above). On the transverse septum run the popliteal vessels and the tibial nerve. The proximal margin of the soleus overlaps the distal margin of the popliteus. The synovial membrane of the knee-joint sends a prolongation between its tendon and the back of the lateral condyle of the tibia.
Variations. — It is rarely absent. An accessory head may arise from the medial side of the lateral condyle or from some neighbouring structure. The fibulo-tibialis (peroneo-tibiaUs) is a small muscle found by Gruber in one body in seven. It arises from the medial side of the head of the fibula and is inserted into the posterior surface of the tibia beneath the popliteus.
Of the three muscles of this group, the flexor digitorum longus lies on the tibial side of the leg, the flexor hallucis longus on the fibular side, and the tibialis posterior upon the interosseous membrane, partly covered by the other two
muscles, beneath the former of which it crosses, distally, to the tibial side of the leg. Septa separate the flexor muscles from the tibialis. The tendons of the three muscles pass behind the medial malleolus, held in place by the transverse septum and the deep layer of the laciniate (internal annular) ligament. They lie
Tendo Achillis
in compartments divided by septa which descend to the tibia. The compartment for the tibialis posterior is the most medial. It is partly overlapped by that for the flexor digitorum. At the ankle the tendon of the tibialis passes above, the tendon of the flexor digitorum medial to, and that of the flexor hallucis below, the sustentaculum tall, each in a separate osteo-fibrous canal bounded
Diagram.
/in the diagram indicates the region through which passes section F, fig. 414 (p. 478). 1. Arteria peronea. 2. A. plantaris mediaUs (internal). 3. A. plantaris lateralis (external). 4. A. tibiahs anterior. 5. Aponeurosis plantaris. 6. Calcaneus. 7. Fascia pedis dorsalis. 8. F. plantaris — a, lateral; b, intermediate; c, medial. 9. Ligamentum cruciatum (anterior annular). 10. L. laciniatum (internal annular). 11. Malleolus lateralis (external). 12. Malleolus medialis (internal). 13. Musculus abductor hallucis — a, tendon. 14. M. abductor quinti digiti — a, insertion. 15. M. adductor hallucis — a, oblique head, origin; b, transverse head. 16. M. extensor digitorum brevis — a, tendons. 17. M. extensor digitorum longus, tendons. 18. M. extensor hallucis longus, tendon. 19. M. flexor digitorum brevis — a, tendon. 20. M. flexor digiti quinti brevis — a, tendon. 21. M. flexor digitorum longus, tendon. 22. M. flexor hallucis brevis tendon. 23. M. flexor hallucis longus. 24. M. interossei dorsales. 25. M. interossei plantares. 26. M. lumbricales. 27. M. peroneus brevis. 28. M. peroneus longus. 29. M. peroneus tertius — a, tendon. 30. M. planaris, tendon. 31. M. quadratus plantae. 32. M. tibialis anterior, tendon. 33. M. tibialis posterior, tendon. 34. Nervus peroneus profundus. 35. N. peronsus superficialis (musculo-cutaneous). 36. N. plantaris medialis (internal). 37. N. plantaris laterahs (external). 38. N. surahs (external saphenous) . 39. Os cuneiform I, 40. Os cuneiform III. 41. Os cuboid. 42. Osmetacarpalel. 43. Os metacarpalell. 44. Os metacarpale III. 45. Os metacarpale IV. 46. Os metacarpale V. 47. Os naviculare. 48. Ossa sesamoidea. 49. Os talus (astragalus). 50. Tendo Achillis 51. Retinacula mm. peroneorum. 52. Septum intermusculare laterale. 53. S. intermusculare mediale. 54. Vena saphena magna.
externally by the laciniate (internal annular) ligament. In the sole the tendon of the long flexor of the big toe passes under (deeper than) the tendon of the flexor digitorum, to which it gives a slip, and is inserted into the terminal phalanx of the big toe. The tendon of the long flexor of the toes passes obliquely across the sole, is joined by the quadratus plantae (flexor accessorius), and gives rise to a tendon for the terminal phalanx of each of the four lateral toes. From these tendons the lumbrical muscles arise. The tibialis posterior has an extensive insertion on the plantar surface of the tarsus.
they invert and extend the foot.
The long flexors of the toes probably represent the flexor profundus and the flexor polhcis longus of the forearm. The tendons of the deep flexors of the forearm do not, however, cross like those of the long flexors of the toes. In the lower mammals there is much variation in the toes to which the tibial and fibular flexors are distributed. The tibiahs posterior has no certain representative in the forearm. The rare ulno-carpeus may represent it.
The flexor digitorum longus (figs. 416, 420). — Origin. — From the popUteal line, the medial side of the second quarter of the dorsal surface of the tibia, the fibrous septum between the muscle and the tibiahs posterior, and the fascia covering its proximal extremity.
Structure and insertion. — From these areas of origin the fibre-bundles run obUquely to be inserted in a penniform manner on a tendon which begins in the proximal quarter of the muscle as a narrow septum, and more distally becomes a strong band on the medial margin. The insertion of the fibre-bundles continues nearly to the medial maUeolus. From here the tendon passes behind the medial malleolus, dorso-lateral to the tendon of the tibiahs posterior, crosses the posterior talo-tibial ligament, and passes along the medial margin of the sustentaculum tali into the sole of the foot. Here it crosses the tendon of the flexor hallucis longus, from which it receives a tendinous slip, and divides into four parts, which pass to the second to the fifth toes. Each tendon is bound to the phalanges of the toe to which it passes by a fibrous sheath. Superficial to it in the sheath lies a tendon of the flexor digitorum brevis, which the
is connected, like those of the fingers, by vincula tendinum, to the phalanges of the toes.
Nerve-supply. — From the tibial (posterior tibial) nerve a branch arises, often in company with nerves to some other or others of the muscles of this group. The nerve divides into two branches, one of which passes to the lateral side of the muscle, where it extends along near the middle of the fibre-bundles of that side, while the other branch passes along near the middle of the fibre-bundles of the medial side of the muscle.
Relations. — In the proximal half of the leg it lies on the tibia, in the distal half on the posterior tibial muscle. Between it and the flexor hallucis lie the posterior tibial vessels and nerve. Near the ankle the plantar vessels and nerves cross the tendon of the muscle, separated from it by the deep layer of the laciniate (internal annular) ligament. In the upper two-thirds of its extent it is covered by the triceps surte. In the lower third of the leg it emerges medial to the soleus and the tendon of Achilles. The relations of its tendon at the ankle have been described above. The tendon Ues beneath the origin of the abductor hallucis muscle and in the sole is covered by the flexor digitorum brevis, crosses the tendon of the long flexor and the oblique adductor of the big toe and the interosseous muscles, is joined by the quadratus plantse (flexor accessorius), and gives origin to the lumbrical muscles.
The flexor hallucis longus (figs. 416, 420). — Origin. — From the distal two-thirds of the posterior surface of the fibula, the septa between it and the tibialis posterior and peroneal muscles, and the fascia above its proximal extremity.
Structure and insertion. — The fibre-bundles converge upon a tendon which begins in the second quarter of the muscle, within its substance, and emerges upon the postero-medial margin in its distal half. The insertion of the fibre-bundles continues to the end of the tibia. From here the tendon passes over the dorsal talo-tibial (tibio-astragaloid) ligament, and through the groove on the posterior surface of the talus and the under surface of the sustentaculum tali, where it lies on the fibular side of the tendon of the flexor digitorum longus. It then crosses the deep surface of this tendon, to which it gives a slip, passes over the plantar surface of the medial head of the flexor hallucis brevis, and between the sesamoid bones of this muscle into the osteo-fibrous canal on the plantar surface of the big toe. It is inserted into the base of the terminal phalanx of the big toe.
Nerve-supply. — The nerve arises from the tibial (posterior tibial) nerve, often in company with the nerve to the flexor digitorum longus or the other muscles of the group. It runs along the deep surface of the muscle and sends twigs into the middle third of its constituent fibre-bundles. Sometimes two nerves are furnished to the muscle.
Relations. — It hes on the fibular side of the distal two-thirds of the leg. ProximaUy it diverges from the preceding muscle so as to disclose the tibiahs posterior, which is more deeply situated. Between it and the tibialis posterior he the peroneal vessels. Distally its tibial margin approaches the flexor digitorum longus, but between them lie the posterior tibial vessels and nerve. Lateral to it lie the peroneal muscles. It is covered in the leg by the soleus. In the distal part of the leg its tendon hes medial to the tendon of Achilles. On entering the foot the tendon crosses beneath the abductor hallucis muscle and the lateral plantar vessels and nerve. The other relations of the tendon have been described above.
The tibialis posterior (figs. 416, 422). — Origin. — From — (1) the lateral half of the distal margin of the popliteal line and the middle third of the posterior surface of the tibia; (2) the medial side of the head and of that part of the body of the fibula next the interosseous membrane in the proximal two-thirds; (3) from the whole of the proximal and the lateral portion of the distal part of the posterior surface of the interosseous membrane; and (4) from the septa between its proximal portion and the long flexor muscles.
Structure. — From this extensive area of origin the fibre-bundles converge upon a tendon which is at first deep seated within the muscle-belly, but about the middle of the leg emerges on the medial margin of the muscle. The fibular portion of the muscle is much more extensive than the tibial. The proximal fibres take a nearly perpendicular, the most distal (from the fibula) a nearly transverse, course. The insertion of fibres stops a little proximal to the medial malleolus. The tendon then extends to the medial side of the tendon of the long flexor of the toes, passes through the groove on the back of the malleolus, across the medial talo-tibial (tibio-astragaloid) ligament, and above the sustentaculum tali to the sole.
Insertion. — The tendon divides into two chief divisions, a deep and a superficial. (1) The deep portion becomes attached chiefly to the tubercle of the navicular bone, and usually in part also to the first cuneiform. (2) The superficial spreads out to be attached chiefly to the third cuneiform and the base of the fourth metatarsal, but also in part to the second cuneiform, to the capsule of the naviculo-cuneiform joint, to the sulcus of the cuboid, and usually also to the origin of the short flexor of the big toe and the base of the second metatarsal. Shps may, however, also be given to other structures. A sesamoid bone is usuaUy found in the tendon either near the calcaneo-navicular hgament or the navicular bone.
Nerve-supply. — The nerve arises from the tibial (posterior tibial) in company often with branches to the other muscles of the group. It enters the posterior surface of the muscle in its proximal third, and gives off one or two branches for the tibial fasciculus. The main trunk descends across the middle third of the fasciculi arising from the fibula.
Relations. — The muscle covers the posterior surface of the interosseous membrane, and extends distally over the posterior surface of the tibia beneath the flexor digitorum longus. It is covered proximally by the soleus, distally by the two long digital flexors. The posterior tibial and peroneal arteries and the tibial (posterior tibial) nerve run upon its posterior surface. The tendon in the sole is under cover of the origin of the plantar muscles of the big toe.
Action. — The tibialis posterior adducts the foot and slightly inverts it. The flexor digitorum longus flexes the terminal phalanx on the second and the second on the first, and at the height of its contraction the first on the metatarsals. It also rotates medially to some extent the ends of the fourth and fifth toes, and inverts the foot. The flexor haUucis longus flexes
of the three in this respect.
Variations. — The muscles of the group may be more or less fused with one another or be united by fascicuh. This is especially common between the two flexors of the toes. The individual muscles vary in development. The flexor digitorum longus may be more or less divided into separate fasciculi for the individual toes. The slip from the flexor haUucis longus to the flexor digitorum longus varies greatly in extent, but usually passes mainly to the second and third toes, more rarely to the second, third, and fourth, and very rarely to the fifth. In most of the apes the tibial flexor (flexor digitorum) sends tendons to the second and fifth, the fibular flexor (flexor haUucis) to the first, third, and fourth toes. This condition is also sometimes found in man. A slip may pass from the tendon of the flexor digitorum to that of the flexor haUucis longus. There may be a sesamoid bone in the tendon of the flexor haUucis longus as it passes over the talus (astragalus) and calcaneus. The tibiahs posterior may be doubled. Aberrant fasciculi may arise from various regions on the back of the leg and join any one of the three muscles of the group.
Abnormal muscles. — The soleus accessorius. — Arises by a tendon from the head of the fibula beneath the soleus. It is usually a slender muscle inserted into the medial surface of calcaneus. The tibialis secundus (tensor of capsule of ankle-joint). — A smaU muscle which arises from the tibia beneath the flexor digitorum and is inserted into the capsule of the anklejoint. The fibulo-calcaneus medialis (peroneo-oalcaneus internus of MacAlister, flexor accessorius long. dig. long., etc.). — A fasciculus which arises from the lower third of the body of the fibula and gives rise to a tendon which passes beneath the laciniate hgament to the quadratus plantse or to the tendon of the flexor digitorum longus.
Vagina m. flexoris digitorum longi. — The tendon is surrounded by a synovial sheath from the back of the medial malleolus to where it crosses the tendon of the flexor haUucis longus below the navicular bone. It may communicate with the sheath of the tibialis anterior or with that of the flexor haUucis longus. Vaginae tendinum digitales. — The tendons of the long flexor, together with those of the short flexor, are surrounded by synovial sheaths from the heads of the metatarsals to the insertions of the tendons. In structure these resemble those of the fingers. Vagina m. flexoris haUucis longi. — The tendon is surrounded by a sheath from the back of the medial malleolus to the crossing of the tendon of the flexor digitorum longus. Another sheath surrounds the tendon from the middle of the first metatarsal to its insertion. Vagina m. tibialis posterioris. — The tendon is surrounded by a synovial sheath extending from a region proximal to the medial malleolus to the insertion of the tendon.
On the dorsum of the foot there is a muscle not represented in the hand, the extensor digitorum brevis (fig. 418). In the sole of the foot there is a highly developed musculature which may be subdivided into the flexor digitorum brevis (fig. 419); the muscles connected with the long extensor of the toes, quadratus plantse and lumbricales (fig. 420); the intrinsic muscles of the great toe, (figs. 419, 421); the intrinsic muscles of the little toe (figs. 419, 421); and the interosseous muscles (fig. 422). These muscles abduct and adduct the toes, flex them at the metacarpophalangeal joints and flex and extend them at the first row of interphalangeal joints. On the second row of interphalangeal joints they seem to exert relatively little action. All the movements, excepting flexion, are weak in most individuals. The extensor digitorum brevis is innervated by the deep peroneal (anterior tibial) nerve. The muscles of the sole of the foot are all innervated by the lateral (external) plantar, except the flexor digitorum brevis, the most medial of the lumbrical muscles, and the abductor and flexor brevis of the great toe, which are innervated by the medial (internal) plantar.
dense fibrous tissue.
Muscle fasciae. — Over the dorsum of the foot a fascial membrane extends from the cruciate ligament mentioned above to the toes, where it is continued as fibrous sheaths for the extensor tendons. Laterally and mediaUy it is continued into the plantar fascia. Where
it overlies skeletal structures it becomes adherent to them. In the main this fascial sheet is thin. Over the base of the first metatarsal it is strengthened by a band which runs from the medial side of this bone over the extensor tendons of the big toe to the base of the second metatarsal. The extensor digitorum brevis is covered by an adherent fascial sheet. The dorsal surface of each dorsal interosseous muscle is likewise covered by an adherent membrane.
The plantar surface of the foot is invested by a fascia in which three distinct regions may be observed, a central, a lateral, and a medial. The central region is greatly thickened by bands of fibrous tissue, the plantar aponeurosis, which diverge toward the toes from the medial half of the tuber calcanei. These bands become distinct from one another as the toes are approached, and each finally terminates partly in the skin over the head of the corresponding metatarsal and in the digital sheath of the flexor tendons. Some of the fibres are continued into the transverse capitular ligaments, the others extend through near the metatarsophalangeal articulation to the dorsum of the foot. Broader, thicker bands go to the three middle toes than to the big and little toes. At the margins of this central area some fibres radiate into the fascia of the lateral and medial area, some extend lateraUy into the skin, and some sink into the intermuscular septa described below. Near the toes well-marked transverse bundles of fibres may be seen between the digital bands. The central area of the plantar fascia is not densely adherent to the skin.
The medial plantar fascia is thin and adherent to the skin. It extends between the central plantar and the dorsal fascia over the intrinsic muscles of the big toe. The lateral plantar fascia is thick and well developed near the heel, thin as the little toe is approached. A dense band, the calcaneo -metatarsal ligament, strengthens it between the calcaneus and the tuberosity of the fifth metatarsal.
At the junction of the lateral with the central region of the plantar fascia the lateral intermuscular septum sinks in to be attached to the first cuneiform, the navicular and the tendon of the posterior tibial. A similar medial intermuscular septum sinks in between the medial and central regions of the plantar fascia and is attached to the long plantar hgament, the tendon sheath of the peroneus longus and the base of the fifth metatarsal. The fascia of each of these regions in considerable part extends into these septa instead of becoming continuous across them.
The sole is thus divided into three great fascial compartments by these septa, a lateral, a central, and a medial. In the lateral fie the intrinsic pedal muscles of the little toe; in the medial, the abductor and the flexor brevis of the big toe and the distal end of the tendon of the flexor hallucis longus. The central compartment is subdivided by transverse septa into several sub-compartments. In the most superficial compartment lies the flexor digitorum brevis; in the second, the tendons of the flexor digitorum longus and its associated muscles, the quadratus plantse (flexor accessorius) and the lumbrical muscles; in the third, the adductor muscles of the big toe; and in the fourth, the interosseous muscles.
The first two sub-compartments are most clearly marked in the region of the tarsus. Distally they become merged by the disappearance of the intervening transverse septum, and longitudinaUy subdivided by fibrous septa which serve to make a complete sheath over each digit for the flexor tendons. The sheath over the adductor muscle of the big toe is a thin membrane continued laterally from the medial intermuscular septum. Where the two heads of the adductor muscle advance upon their tendon of insertion, the medial septum has no skeletal attachment, so that the adductor sub-compartment of the middle fascial compartment communicates freely with the medial compartment. Over the cuneiform bones the tendon of the flexor hallucis longus passes from the long flexor region of the middle compartment into the medial compartment. Here the medial intermuscular septum divides into two layers, which form a sheath for the tendon as it passes to the plantar surface of the flexor hallucis brevis.
1. Muscle of the Dorsum of the Foot
The extensor digitorum brevis (fig. 418). — This muscle is broad and thin, lies beneath the tendons of the long extensor muscle on the tarsus, lateral to the navicular and the head of the talus, and sends tendons to the four more medial toes. It arises from the calcaneus. Its nerve-supply is from the deep peroneal.
apex of the cruciate hgament.
Structure and insertion. — The fibre-bundles arise directly from the hgament, and by short tendinous bands from the bone. As they extend distally they become grouped into four beUies. Those of the most medial and largest beUy, the extensor hallucis brevis, become inserted in a bipenniform manner on the lateral and medial margins of a tendon which begins opposite the cuboid. The insertion of fibre-bundles continues to the base of the first metatarsal. The insertion of the fibre-bundles of the other belUes, which are seldom so distinctly isolated as the first, takes place in a penniform manner into their respective tendons, but the exact mode of attachment is subject to great individual variations. The tendon of the first digit is inserted mainly into the middle of the back of the base of the first phalanx, but it is often also united to the tendon of the long extensor. The other three tendons are fused with the lateral margins of the corresponding tendons of the long extensor near the bases of the three middle digits. They also usually give shps to the bases of the first phalanges of the corresponding toes.
Nerve-stipply. — The deep peroneal (anterior tibial) nerve, which, accompanied by the anterior tibial artery, passes beneath the medial beUy of the muscle, gives off a branch which passes transversely across the middle of the deep surface of the muscle and sends twigs into it.
toes. The relations of its tendons have been described above.
Action. — It aids the long extensors in extending the first phalanx of each of the four medial digits. It has but a limited action on the second and third phalanges. It serves also to pull the ends of the toes to which its tendons go toward the little toe.
Variations. — The muscle shows great variation in development. Rarely the whole muscle, more frequently one or more of its digital divisions, may be missing. On the other hand, it may be more highly developed than usual. Accessory fasoicuh vary greatly in origin and termination. Most frequently their tendons go to a metacarpo-phalangeal articulation or to the second or the fifth toe.
The flexor digitorum brevis, the most superficially placed of the plantar muscles, lies in the mid-plantar region beneath the plantar fascia and over the tendons of the long flexor of the toes and its associated muscles. It arises from the calcaneus, and has a flat, elongated belly, which toward the middle of the sole is prolonged into four processes, each of which has a special tendon that is inserted into the second phalanx of one of the four lateral toes. The tendons of the muscle correspond to those of the flexor sublimis in the palm. The belly of the flexor
Structure. — The constituent fibre-bundles pass distally in a compact mass. The tendons of insertion begin within the muscle substance, and as the fibre-bundles become inserted on them, the separate fascicuh become more and more distinct. The fascicuU for the second and third toes are larger and arise more superficially than those for the fourth and fifth toes. The fasciculus for the fifth toe is often very small, and its tendon takes an obhque course to the insertion.
Insertion. — The tendons of the short flexor pass superficial to those of the long flexor into the osteo-fibrous canals on the flexor surface of the digits. Upon the first phalanx of each toe the tendon of the short flexor divides and forms an, opening (chiasma tendinis) through which
the tendon of the long flexor passes, while the tendon of the short flexor becomes attached to the base of the second phalanx. The arrangement is essentially Uke that described at length for the flexors of the fingers (p. 401).
Relations. — The short flexor is sejiarated from the abductors of the big toe and little toe by strong intermuscular septa (p. 492), and from the long flexor tendons and the quadratus plantaj (flexor accessorius) by a transverse septum in which the lateral plantar vessels and nerve cross the foot. In its distal two-thirds it is separated from the plantar fascia by loose tissue.
Variations.— The muscle shows a tendency toward reduction, one or more of its fasciculi being frequently absent, and occasionally the whole muscle. The fasciculus for the fifth toe is absent in about 20 per cent, of bodies (Le Double). When a fasciculus is absent, its tendon is usually replaced by an accessory tendon from the long flexor. The muscle or its tendons may be more or less fused to the tendons of the flexor digitorum longus.
The muscles belonging in this group are the quadratus plantae (flexor accessorius), a flat, quadrangular, bicipital muscle which runs from the medial and plantar surface of the body of the calcaneus to the dorso-lateral margin and deep surface of the long flexor tendon; and the lumbrlcales, four slender bipinnate muscles which run from the medial sides of the digital slips of the tendon to the medial sides of the four more lateral toes. The quadratus aids the long flexor muscle; the lumbricales extend the last two phalanges and flex the first phalanx of each of the digits to which they pass. The lumbrical muscles correspond to those of the hand. The quadratus is not there represented. The nerve-supply is from the lateral (external) plantar nerve except that for the first lumbrical muscle which gets its supply from the medial (internal) plantar.
The quadratus plantae (flexor accessorius) (fig. 420). — This muscle arises by two headsThe lateral head springs by an elongated tendon from the calcaneus in front of the lateral process of the tuber, and from the lateral margin of the long plantar hgament. The medial head arises directly from the medial surface of the body of the calcaneus as far back as the medial process of the tuber calcanei, and from neighbouring hgaments.
Structure and insertion. — The two heads are separated at their origin by a short triangular space. They soon fuse to form a single beUy, but the fibre-bundles of each head in the main are separately inserted. Those from the lateral head diverge to be attached to the lateral margin of the flexor tendon. Those from the medial head are inserted on a tendon that begins on the medial margin and deep surface of this head, becomes broader, and is inserted as a flat aponeurosis on the deep surface of the flexor tendon. There are great individual variations in the structure of this muscle. The flbres of either part may be inserted with those of the other part.
Relations. — The muscle Ues in a fascial compartment with the long flexor tendons. This compartment is bounded on each side by intermuscular septa, deeply by the tarsus, and plantarward by a septum which intervenes between it and the flexor digitorum brevis, and in which the lateral plantar nerve and vessels cross to the lateral side of the foot.
traction on the toes parallel with the long axis of the foot.
Variations. — It is frequently reduced in size. The lateral head is not infrequently missing, the medial head or the whole muscle much more rarely. The mode of attachment to the tendon varies. It may be inserted in part or wholly into the long flexor of the great toe. It may receive, in about one body in twenty (Wood), an accessory slip of origin from the fibula, one of the muscles of the leg, the fascia of the leg or foot, or the medial surface of the calcaneus, etc.
The lumbricales. — The three lateral muscles arise from the contiguous sides of the digital tendon-slips of the flexor digitorum longus in the angles of division. The first lumbrical arises on the medial margin of the tendon to the second toe. The fibre-bundles of each muscle converge on both sides of a tendon which becomes free near the metatarso-phalangeal joint and is attached to the medial side of the first phalanx of the toe to which the muscle belongs. A tendinous expansion is sent into the aponeurosis of the extensor muscle.
Nerve-supply. — The three lateral lumbrical muscles are most frequently supplied by branches of the deep ramus of the lateral plantar nerve, the medial by the first common plantar digital branch of the medial plantar nerve. The latter nerve may supply the two more medial muscles or the more medial muscles may receive a double supply. The branches of the lateral plantar nerve enter the deep surfaces of the muscles in the middle third. The branches of the medial plantar enter the medial borders of the muscles near the junction of the proximal and middle thirds.
Relations. — The lumbrical muscles lie in a plane with the long flexor tendons deeper than the flexor brevis tendons and superficial to the adductor hallucis. The deep branches of the lateral plantar nerve and vessels pass across their deep surface; superficial branches of both plantar nerves across the superficial surface.
Variations. — One or more of the muscles may be absent. Sometimes a muscle is doubled. This is more frequently the case with the third and fourth muscles. The first may arise wholly from the tendon of the posterior tibial muscle or from this and the Ions flexor of the big toe. The third lumbrical may arise from the flexor digitorum brevis. The second and fourth lumbricals may be inserted into the tendons of the flexor digitorum brevis.
These muscles are the abductor, flexor brevis, and adductor. Of the three muscles, the first two lie in the medial fascial compartment, while the last lies in the middle compartment covered by the flexor digitorum longus and its associated muscles.
The abductor hallucis (fig. 419), the largest and most superficial of these muscles, lies on the border of the sole medial to the short flexor muscle. It passes from|the calcaneus across the tendons of the long flexor muscles, and is inserted into the medial side of the base of the first phalanx of the great toe and into the medial side of the long extensor tendon. It is partly fused to the medial belly of the flexor hallucis brevis. The flexor hallucis brevis (fig. 421) is a bicaudal muscle which lies over the first metatarsal. It arises in the region of the cuneiform bones and is inserted on each side of the base of the first phalanx. Between
Tendon of flexor digitorum brevis
its two bellies and insertions runs the tendon of the long flexor of the great toe. Proximally and medially the flexor brevis is crossed by the abductor hallucis. Its tendons are fused with those of the abductor and the oblique head of the adductor. The adductor hallucis (fig. 421) is composed of two distinct heads, an oblique and a transverse. The oblique head extends from the long plantar ligament under cover of the tendons of the flexor digitorum longus and the lumbrical muscles to the lateral side of the base of the first phalanx of the great toe. Its tendon of insertion is joined by the transverse head, which arises from the capsules of the third to the fifth metatarso-phalangeal joints. Beneath the adductor lie the more medial interosseous muscles.
These muscles perform not only the functions indicated by their names, but also extend the second phalanx. They correspond fairly well with those of the thumb. The opponens is not normally present in the foot. The nerve supply for the adductor is from the lateral (external) plantar nerve; that for the other muscles is from the medial (internal) plantar.
annular) ligament; (4) the septum between the muscle and the flexor digitorum brevis; and (5) a fibrous arch which extends on the deep surface of the muscle over the plantar vessels and nerves and the long flexor tendons from the calcaneus to the navicular bone.
Structure. — From the medial process of the tuber calcanei a tendinous band passes to the deep, lateral side of the muscle. Numerous tendinous bands arise from the other areas of origin. The fibre-bundles arise from these tendons and directly from the fibrous arch. They are attached in a penniform manner to numerous tendinous slips which extend far up in the muscle. These slips become graduahy fused into a tendon which appears on the superficial plantar aspect of the muscle. Opposite the distal half of the first metatarsal bone the tendon leaves the belly of the muscle and becomes closely bound to the medial belly of the flexor hallucis brevis.
Relations. — It is covered by the plantar fascia and is separated from the muscles of the median compartment by the medial intermuscular septum. It crosses the tendons of the tibialis anterior, tibiahs posterior, flexor digitorum longus, and flexor hallucis longus muscles and the plantar vessels and nerves.
The flexor hallucis brevis (fig. 421). — Origin. — From a tendon attached to the first (internal), second and third cuneiform bones. The more lateral of its fibres are continued into the plantar calcaneo-cuboid Ugament and the more medial into the expansion of the tendon of the posterior tibial muscle.
Structure and insertion. — The fibre-bundles give rise to two belHes, a medial and a lateral. Those of the medial belly pass obUquely medially to be inserted into the tendon of the abductor hallucis, and by a short tendon fused with this into the medial side of the plantar surface of the base of the first phalanx. This tendon contains a sesamoid bone. Those of the lateral converge upon the tendon of the oblique head of the adductor, and the two muscles are inserted by a common tendon, which contains a sesamoid bone, into the lateral side of the plantar surface of the base of the first phalanx.
Nerve-suy-ply. — A branch from the medial plantar (or first plantar digital) nerve divides over the plantar surface of the muscle and gives a twig to each belly near the middle third. Rarely the lateral belly may receive a branch from the lateral plantar nerve.
on its superficial surface.
The adductor hallucis (fig. 421). — The oblique head. — Origin. — From (1) the tuberosity of the cuboid and the sheath over the tendon of the peroneus longus muscle; (2) the plantar calcaneo-cuboid hgament; (3) the third cuneiform; (4) the bases of the second and third metatarsals and (5) a fi^brous arch which extends from the plantar calcaneo-cuboid Ugament to the interosseous fascia.
Structure and insertion. — From short tendon-slips the fibre-bundles pass forward to form a thick, fusiform belly which is attached in a bipeuniform manner to a flat tendon. The tendon begins about the middle of the plantar surface of the muscle and is inserted in common with that of the flexor brevis into the lateral side of the plantar surface of the base of the first phalanx, and by a sUp into the aponeurosis of the long e.xtensor muscle on the back of the big toe.
phalangeal joints and from the transverse capitular hgaments.
Structure and insertion. — Of the three fasciculi, that to the little toe Hes nearest the heel, that to the middle toe the most distally. The fibre-bundfes take a nearly parallel course to be attached to tendon-shps which are fused into a common tendon that sphts and passes on each side of the tendon of the obUque head and is inserted into the sheath of the tendon of the long flexor of the great toe (Leboucq).
Relations. — The adductor hallucis is crossed superflciaUy by the tendons of the flexor digitorum longus and by the lumbrical muscles. On its deep surface he the interosseous muscles, and the deep plantar vessels and nerves.
Action. — The actions of the muscles of this group are indicated by the names of the individual muscles. The abductor and the obhque head of the adductor are also flexors of the first phalanx. All the muscles of the group aid in extending the second phalanx. The transverse head of the adductor serves to draw together the heads of the metatarsals after they have been separated by the weight of the body during the tread.
Variations. — The extent of fusion of the abductor and adductor with the two heads of the short flexor varies considerably. The' abductor may receive an accessory fasciculus from the medial border of the foot. Either the adductor or the flexor brevis may send a tendon to the base of the first phalanx or to the short flexor tendon of the second toe. The adductor shows frequent variations in relation to its metatarsal attachments, owing to the fact that originally a fasciculus from the body of the second (and third) metatarsal was probably normally present and the transverse head was more developed (Leboucq). The opponens hallucis is a fasciculus occasionally found which extends from the short flexor or the medial intermuscular septum to the body of the first metatarsal. This muscle is normal in some monkeys. An adductor digiti secundi has been seen to arise from various sources and become attached to the lateral side of the plantar sm-face of the base of the first phalanx of the second toe. This muscle may be fused with the oblique adductor. A corresponding muscle is found normally in some apes, and in some of the lower animals there is a special adductor for each toe.
In this group belong three muscles, an abductor, a flexor and an opponens. The largest of these, the abductor digiti quinti (fig. 419), extends superficially over the lateral margin of the foot from the lateral side of the tuber calcanei to the base of the little toe. The flexor digiti quinti brevis (fig. 421) is a small, flat muscle ,which lies on the plantar surface of the fifth metatarsal. The opponens is a small muscle lying lateral to this. The two, which are often fused, arise from the cuboid. The flexor brevis is inserted into the plantar side of the base of the first phalanx of the little toe. The opponens is inserted into the lateral surface of the metatarsal. The abductor corresponds with the abductor of the little finger. The opponens and flexor brevis correspond probably with the deep part of the opponens of the little finger. The nerve supply is from the lateral plantar nerve.
The abductor digiti quinti (fig. 419). — -Origin. — From (1) the lateral process of the tuber calcanei and the lateral and plantar surface of the body of the bone in front of this; (2) the lateral intermuscular septum; (3) the deep surface of the lateral plantar fascia, including the fibrous band extending from the calcaneus to the lateral side of the base of the fifth metatarsal bone.
Structure. — The fibre-bundles run obhquely to a flat tendon of insertion. This begins within the muscle near the calcaneo-cuboid joint, soon emerges on the medial side of the deep surface, and becomes free near the metatarso-phalangeal joint. Considerable individual variation in structure is found.
glides over the tuberosity of the fifth metatarsal, it frequently sends a second fasciculus to be attached to this bone (abductor ossis metatarsi quinti) . A special fasciculus from the tuberosity often constitutes the lateral margin of the muscle.
Nerve-supply. — The nerve arises from the lateral plantar. It may be distributed either near the deep or the superficial surface of the muscle. The former appears to be the case when the muscle is slightly developed. The chief intramuscular branches then extend across the middle third of the constituent fibre-bundles near the deep surface. In case the calcaneo-metatarsal bundles are well developed, the nerve enters the proximal margin of the muscle and its chief branches extend across the middle third of the more superficial muscle-bundles, finally terminating in the distal margin of the muscle.
Relations. — It is ensheathed by the plantar fascia and the lateral intermuscular septum. It lies superficial to the quadratus plantoe (flexor accessorius), the opponens and flexor Ijrevis of the Mttle toe, the long plantar hgament, and the tendon of the peroneus longus muscle.
Structure and insertion. — The fibre-bundles take a nearly parallel course, although the belly is slightly fusiform. They are attached by short tendinous bands to the base of the first phalanx of the little toe, the capsule of the corresponding joint, and the aponeurosis on the dorsal surface of the toe.
fifth toe. Medially it lies superficial to the third plantar interosseous muscle.
The opponens digiti quinti. — This muscle arises from the sheath of the peroneus longus and the tuberosity of the cuboid by a slender tendon which passes over the tuberosity of the fifth metatarsal and gives rise to fibre-bundles which are inserted on the lateral surface of the fifth metatarsal.
ally in a plantar direction.
Variations. — The muscles of this group may be more or less completely fused. The abductor, in addition to the variations mentioned above, may send tendons to the third and fourth metatarsals. The opponens is frequently missing. The abductor accessorius digiti quinti is a rare muscle which arises from the lateral process of the tuber of the calcaneus and is inserted into the lateral surface of the base of the first phalanx of the httle toe.
Two groups of interosseous muscles are recognised, a dorsal and a plantar. The dorsal are the larger and fill the interspaces. The first two are inserted into each side of the base of the first phalanx of the second toe; the third and fourth into the lateral sides of the bases of the first phalanges of the third and fourth toes. The plantar interossei lie on the medial side of the ventral surfaces of the third, fourth, and fifth metatarsals, and are inserted each on the medial side of the base of the first phalanx of the corresponding toe. In the hand the axis about which the interosseous muscles are arranged passes through the middle finger, in the foot through the second toe. The nerve-supply is from the lateral plantar nerve.
The interossei dorsales. — Each of the three lateral dorsal interosseous muscles arises from — (1) the sides of the shaft and the plantar surface of the bases of the metatarsal bones bounding the space in which it lies; (2) from the fascia covering it dorsally; and (3) from fibrous prolongations from the long plantar hgament. The first has a similar origin except that it is attached medially to the base of the first metatarsal and to a fibrous arch extending from the base to the head.
Insertion. — The first and second on each side of the base of the first phalanx of the second toe. The third and fourth on the lateral side of the bases of the proximal phalanges of the third and fourth toes. Each tendon is adherent to the capsule of the neighbouring joint. They send no well marked processes to the extensor tendons, as do those of the hand.
The interossei plantares. — Each plantar interosseus arises — (1) from the proximal third of the medial plantar surface of the shaft and from the base of the metatarsal on which it Ues; and (2) from expansions of the long plantar hgament.
Structure and insertion. — The obliquely placed fibre-bundles are longer than those of the dorsal interossei, and are inserted in a tendon which hes near the medial border of the muscle, becomes free near the metatarso-phalangeal joint, and is inserted into a tubercle on the medial side of the base of the first phalanx of the digit to which it goes.
Nerve-supply. — From the deep branch of the lateral plantar nerve several rami are given ofi for the interossei. The nerve of each muscle enters the plantar surface in the proximal third. The interosseous muscles of the foiirth interspace, however, are usually supplied by a branch from the superficial ramus of the lateral plantar nerve.
Relations. — -The interosseous muscles are covered on the plantar surface by a thin fascia on which the deep branches of the lateral plantar nerve and vessels run. The first dorsal interosseous adjoins mediaOy the flexor hallucis brevis and laterally on the plantar surface of the second metatarsal, adjoins the second dorsal interosseous. Dorsal and plantar interossei then alternate across the plantar surface of the foot until the fifth metatarsal is reached. Here the third plantar interosseous adjoins the flexor brevis of the little toe.
Dorsal interossei
Action. — The chief axis of the foot may be taken to extend through the second toe. The dorsal interosseous muscles abduct — pull the digits to which they are attached away from this axis; the plantar interosseous muscles adduct — pull the digits toward the axis. The interossei all flex the first row of phalanges.
B. intermetatarsophalangeae. — Four bursse between the neighbouring sides of the heads of the metatarsal bones and dorsal to the transverse capitular ligaments. B. mm. lumbricalium. — Between the ends of the tendons of the lumbrioal muscles and the transverse capitular hgaments. The three medial are more constant than the lateral.
The exact functions of many of the muscles have not yet been decisively determined. Anatomical studies, the construction of mechanical models, the electrical stimulation of the musculature, and observation of the muscular activities of normal individuals and of individuals in whom given muscles or sets of muscles are absent or paralysed, have all proved valuable methods of investigation, but each method has its drawbacks, and knowledge of the part actually played by individual muscles in the normal activities of the body is as yet merely approxi-
FUNCTIONS OF MUSCLES 501
mate. Owing to the influence of gravity, the relations of other muscles to the skeleton, and similar factors, a given muscle may perform functions which would not be deduced from a simple study of the relations of the muscle to the skeleton. Thus the ihacus serves to flex not only the hip, but also the knee, and the hamstring muscles may flex the hip while flexing the knee. The functions ascribed to various muscles in the following tables, although an attempt has been made to base them upon the more recent work on the action of the muscles, must be taken to be merely approximately correct. So far as possible the muscles are given in order of their power in effecting the various movements. In this we have utilized chiefly the work of R. Fiok: "Anatomie und Mechanik der Gelenke unter Berticksichtigung der bewegenden Muskeln" in von Bardeleben's Handbuch der Anatomie des Menschen.
Orbit.
(a) Retractor: Epicranius (occipito-frontalis). The levator palpebrse superioris, innervated by the third cranial nerve, serves to raise the upper lid of the eye. (6) Contractors: orbicularis oculi, corrugator, and procerus. Nasal orifice.
To adduct the pupil: rectus medialis. To abduct the pupil: rectus lateralis. To direct the pupil upward: rectus superior, in association with the obhquus
rotates the chin and carries the jaw toward the opposite side. The rotation may be aided by the digastric of the opposite side. The masseter draws it slightly toward the side on which the muscle lies. This action of the masseter is counterbalanced by the internal pterygoid (Riegner).
inferior.
(/) To narrow it and make it bulge upwards: transversus Unguse. (g) To flatten it: verticalis linguse. When the muscles work symmetrically, these movements are symmetrical; when they
capitis, rectus capitis lateralis.
(6) To extend it: sterno-cleido-mastoid, trapezius, splenius capitis, longissimus capitis, semispinalis capitis, obliquus capitis superior, rectus capitis posterior major and minor. When the hyoid bone and lower jaw are fixed by contraction of the hyomandibular and infrahyoid muscles, the posterior beUy of the digastric aids the extensors of the head in opening the mouth.
9. Muscles acting on the spinal column.
(o) To flex it: sterno-cleido-mastoid, longus colli, longus capitis, psoas major and minor, scaleni, rectus abdominis, obhquus abdominis externus and internus, the crura of the diaphragm, levator ani, and the coccj'geus. .
(6) To extend it: splenius capitis, splenius cervicis, spinahs, sacro-spinaHs, semispinalis dorsi, cervicis and capitis, multifidus, rotatores, interspinales, intertransversarii, levatores costarum, quadratus lumborum.
1. sterno-cleido-mastoid, r. longissimus capitis, r. ilio-costalis, 1. semispinahs, 1. multifidus, 1. rotatores (except the lumbar) , longus colli (r. above, 1. below), 1. serratus anterior and rhomboids, r. levatores costarum.
interoostals, diaphragm.
Enforced inspiration: in addition to the muscles mentioned above, the scaleni, sterno-cleido-mastoid, serratus posterior superior and inferior, rhomboids, serratus anterior, latissimus dorsi, subclavius, pectoralis major and minor, and the extensors of the spinal column, the trapezius and the levator scapuli.
(a) Constriction of the abdominal cavity: obliquus abdominis externus and internus, the transversus and rectus abdominis, and the diaphragm, levator ani, and coccygeus.
(6) Reduction of pressure in the abdominal cavity: the muscles of inspiration, with the exception of the diaphragm, serve to lessen the compression of the abdominal viscera.
tibular (Bartholin's) gland: sphincter urethrae membranaceae and the transversus perinei profundus. (h) To support and Uft the pelvic floor : levator ani, coccygeus, transversus perinei profundus and superficialis.
The two joints acted upon are the sterno-clavicular and the acromio-clavicular. The movements produced consist in lifting and lowering the scapula, carrying it forward and backward and rotating it.
(o) Elevation: trapezius (upper portion), levator scapulae, sterno-cleido-mastoid, rhomboidei, pectoralis major (upper sternal part), serratus anterior (middle portion), omo-hyoid.
(6) Depression: trapezius (lower portion), pectoralis major (lower portion), pectoralis minor, subclavius, latissimus dorsi, serratus anterior (lower part). The weight of the limb is likewise a factor.
When the arm is at the side: pectoralis major, latissimus dorsi, deltoid (posterior and anterior parts), teres major, triceps, coraoobrachialis, short head of biceps, teres minor, infraspinatus.
Forearm supinated: brachialis, long head of biceps, short head of biceps, brachio-radialis, pronator teres, extensor carpi radiahs longus, flexor carpi radialis, extensor carpi radialis brevis, palmaris longus.
Forearm in mid-position or pronated: brachiaUs, long head of biceps, short head of biceps, brachio-radialis, extensor carpi radialis longus, pronator teres, flexor carpi radialis, extensor carpi radialis brevis, palmaris longus.
Forearm extended: short head of biceps, supinator, long head of biceps, brachio-radiahs, extensor carpi radialis longus, abductor poUicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis proprius.
Forearm at right angles: short head of biceps, long head of biceps, supinator, abductor poUicis longus, extensor polhcis brevis, brachioradialis (in pronation), extensor pollicis longus, extensor indicis proprius.
Forearm flexed: short head of biceps, long head of biceps, supinator, abductor pollicis longus, extensor polhcis brevis, extensor pollicis longus, extensor indicis proprius.
(o) To flex it: flexor digitorum sublimis, flexor digitorum profundus, flexor carpi ulnaris, flexor pollicis longus, flexor carpi radialis, abductor pollicis longus, palmaris longus.
(a) To_flex the ulnar side: opponens, long and short flexors of the little finger. (h) To extend the ulnar side: extensor carpi ulnaris, extensor digiti quinti. (c) To adduct the ulnar side: third volar interosseous. {d) To abduct the ulnar side: abductor digiti quinti.
For action on the radial side see " muscles adting on the thumb." Movements of the second, third and fourth metacarpals are produced by the long flexors and the dorsal interosseous muscles.
(a) To flex: all the joints, flexor digitorum profundus; all but the last, flexor digitorum subhmis; the metacarpo-phalangeal joint only, flexor digiti quinti brevis, the lumbrieales, and interossei.
(6) To extend the fingers: extensor digitorum communis, extensor indicis proprius, extensor digiti quinti proprius; to extend the two interphalangeal joints: the lumbrieales, interossei, and frequently the flexor digiti quinti brevis.
(a) To flex it: ilio-psoas, rectus femoris, adductor longus, adductor brevis, obturator externus, tensor fasciae latae, pectineus, sartorius, gluteus minimus, adductor magnus (upper part), gracilis, quadratus femoris.
(6) To extend it: gluteus maximus, adductor magnus (posterior lower part), biceps, semitendinosus, semimembranosus, gluteus medius, piriformis, obturator internus.
longus, quadratus femoris, obturator externus, gracilis, adductor magnus (upper part), pectineus, biceps, semitendinosus, obturator internus and gemelU, semimembranosus.
(/) To rotate it lateralward: gluteus maximus, quadratus femoris, obturator internus, piriformis, rectus femoris, adductor brevis, adductor magnus (lower part), biceps, sartorius, obturator externus gracilis, gluteus medius (posterior part).
tibialis anterior, tibiaUs posterior, flexor digitorvmi longus, flexor hallucis longus, extensor hallucis longus. (J) To evert the foot at Chopart's joint: peroneus longus, peroneus brevis, extensor digitorum longus, peroneus tertius.
(a) To flex: all the joints, flexor hallucis longus, quadrat us plantse, and flexor digitorum longus; the first interphalangeal and the metatarsophalangeal joints of the four lateral toes, flexor digitorum brevis; the metacarpo-phalangeal joints, the lumbricales, interossei, abductor hallucis, adductor hallucis (oblique head), flexor hallucis brevis, abductor digiti quinti, flexor digiti quinti brevis.
(6) To extend; all joints, extensor digitorum longus, extensor hallucis longus, extensor digitorum brevis; the interphalangeal joints, the lumbricales, and the adductors and abductors of the big and little toes.
ductor of the big toe.
References. — For development of the muscular system, consult the list given by W. H. Lewis, Development of the Muscular System, in Keibel and Mall's Human Embryology; for variations: Le Double, Traite cles variations du systeme musculaire de I'homme; for action of muscles: R. Fick, Handbuch der Anatomic und Mechanik der Gelenke unter Berticksichtigung der bewegenden Muskeln, in von Bardeleben's Handbuch, and H. Strasser, Lehrbuch der Muskel und Gelenkmechanik; for the extremities: Frohse und Frankel, Die Muskeln des menschlichen Armes und Beines, in von Bardeleben's Handbuch; for the head and trunk: Eisler, Die Muskeln des Stammes, in von Bardeleben's Handbuch; for the pelvis: Holl, Die Muskeln und Fascien des Beckenausganges. Further references to the literature upon the muscular system may be found in PoirierCharpy's Traite d'anatomie humaine.
THE organs of circulation consist of a system of tubes or vessels which during life are filled with fluid constantly moving in one direction. The major portion of the system is concerned with the continuous distribution of blood throughout the body and is called the haemal or blood-vascular system. A circumscribed part of the hismal circulation is differentiated into a rhythmically contracting propulsory organ called the heart. The minor portion of the system is called the lymphatic system. The lymphatic vessels convey fluid, the lymph, from the tissues to the haemal system.
The essential functions of the blood-vascular system are performed by the smallest of all the blood-vessels, the capillaries [vasa capillaria], which form a network pervading practically all the tissues of the body. Blood is carried to and from the capillaries by larger vessels called the arteries and veins respectively. The heart receives blood from the veins and propels it, in turn, into the arteries.
One of the primary functions of the blood is the transmission of oxygen from the atmosphere to the tissues. In order to do this the blood must of necessity pass through the respiratory organ before being deUvered to the body at large. In gill-breathing vertebrates, the blood, having received oxygen in its passage through the giUs, passes on directly to the tissues._ The entire circuit is here accomplished by a single continuous chain of vessels in which capillaries occur twice, once in the gills and again in the organs and tissues in general. In man, as in other higher vertebrates, lungs assume the function of the gills. Having received oxygen in the lungs the blood is returned again to the heart before being redistributed throughout the body. There are thus in man two separate circuits or systems of blood-vessels, one traversing the lungs and a second ramifying throughout the body. The former is known as the pulmonary circulation; the latter as the systemic. Each has its own arteries, capillaries and veins; the heart is common to both. From the time of birth the heart is longitudinally divided into right and left halves, each of which contains its own independent stream of blood. The blood entering the left side of the heart has issued from the pulmonary circulation and is driven into the systemic; that in the right side, having traversed the systemic circuit, is returned again to the lungs.
The heart and blood-vessels have a continuous lining of flattened cells called endothelium ; the hsemal system is, therefore, a closed circuit.* The main thickness of the heart,_ arteries and veins consists of additional tissue developed around the endothelial lining. It is due to this tissue that the blood is continuously delivered to and withdrawn from the capillaries under suitable pressure and velocity. The heart is mainly composed of rhythmically contracting muscle and its valves are so arranged that the contained blood is driven intermittently in one direction only. The walls of the largest arteries are formed to a great extent of elastic tissue, and, being constantly under tension from within, are instrumental in converting the stream, intermittently received from the heart, into a continuous flow. The walls of the medium sized to smallest arteries are mainly muscular. The smallest arteries are microscopic in size and known as arterioles [arteriote]. The muscular arteries are capable of general or local alterations of calibre regulated by the nervous system; they are thus largely concerned in the maintenance of the blood pressure and in the regulation of the volume of blood entering given localities under varying conditions. The veins have much thinner walls than the arteries; the blood in them is under low tension upon which they e.xercise little or no control.
When an artery divides, the combined calibre of its branches is greater than that of the vessel itself. Since the arteries divide repeatedly the bed of the blood-stream increases in proportion as the vessels diminish in size. The rate of increase, slow at first, becomes enormous in the arterioles. Conversely, the bed of flow undergoes contraction as the heart is approached from the venous side. The velocity of flow in the capillaries must necessarily be much lower
than in the great arteries and veins. From the relative slowness of the blood flow in the systemic capillaries, it has been estimated that then- total bed is eight hundred times greater than the bed of the main arterial stem.
Variations in the course and arrangement of the adult arteries and veins, originally studied by the surgeon for utihtarian purposes only, now furnish one of the most stimulating fields for anatomical research. Text-books can provide, at best, catalogues of the arrangement commonly found in the adult body and of the most ordinary variations. That no text-book description can fit any individual case in all particulars, and that unusual distribution of vessels does not necessarily shorten hfe are among the earhest lessons learned in the anatomical laboratory. The adult vascular pattern is derived from a symmetrical arrangement in the early embryo of which scarcely a trace remains. The intervening changes are so numerous and profound that the general uniformity of vascular distribution Ln different individuals is more remarkable than the occurrence of occasional wide variations from the usual type.
In early stages of development all vessels have a similar structure ; they consist, in fact, of a single layer of endothehum. Some vessels, however, are larger than others; these act as arteries or veins (according to the direction of flow) while the smaller channels perform the office of capillaries. The early principal vessels do not necessarily persist, for many of these dwindle or are lost. New channels are meanwhile in continuous process of formation and some of these may, in turn, become main channels. It thus follows that the main vessels of the adult must be looked upon rather as selected channels through a plexus of possible pathways, than as separate entities which must necessarily conform to given rules of distribution and branching.
In time, no doubt, most of the commoner variations from the usual adult type wUl receive a rational explanation; at present enough has been done to indicate the value of the embryological method. The Ust of v.ariations in the arteries and veins respectively is preceded by a brief account of the morphogenesis of these vessels.
In the case of the heart anomalies frequently result in early death, so that subjects of developmental irregularities are seldom seen in the anatomical laboratory. The anomahes usually consist in improper development of the septa which normally divide the heart and main arterial trunk into their pulmonary and systemic halves. A short account of the morphogenesis of the heart is appended to the description of the adult organ.
1. THE HEART
The heart [cor] is a hollow organ principally composed of muscle, the myocardium. It is lined internally by endocardium which is continuous with the intima of the blood-vessels. Externally, it is covered by the epicardium, a serous membrane continuous with the serous Hning of the pericardium. The form of the heart, when removed from the body without previous hardening, is that of a fairly regular truncated cone. The base [basis cordis] is poorly circumscribed but corresponds, in a general way, to the area occupied by the roots of the great vessels and the portion of the heart-wall between them. The base of the heart is held in position* chiefly by the great vessels, which are attached to the pericardium; the remainder of the organ is capable of free movement within the pericardial cavity.
The interior of the heart is longitudinally divided, into right and left cavities, by a septum passing from base to apex. Each cavity is subdivided into an atrium [atrium cordis] and a ventricle [ventriculus cordis], the former receiving the ultimate venous trunks and the latter giving rise to the main arteries. Thus the left atrium receives the four pulmonary veins, and the right atrium the superior and inferior vena cava and the coronary sinus; the aorta issues from the left ventricle and the pulmonary artery from the right. The ventricles, which constitute the major portion of the heart, may be recognised by their very thick walls. The atria have thinner walls and are less capacious than the ventricles; projecting from each is a diverticulum or auricle [auricula cordis]. The auricles (which receive their name from their resemblance to dog's ears) partially embrace the roots of the pulmonary artery and aorta.
Orientation of the heart. — The apex of the heart [apex cordis] points forward, to the left and downward. The base is directed backward, to the right and upward. The longitudinal axis of the heart forms an angle of about 40° with the horizontal plane and also with the median sagittal plane of the body.
EXTERIOR OF THE HEART
The long axis of the heart is therefore slightly more horizontal than vertical, and slightlymore antero-posterior than transverse. The atria are posterior to rather than above the ventricles. To arrive approximately at the longitudinal axis, it is necessary to select the central point of the base. By cutting the vessels short in several hearts, hardened by formalin before removal, a point immediately to the left of the left lower pulmonary vein was selected in determining the data above given. A steel pin was passed through this point to the apex cordis, and the angles controlled by frontal and transverse sections of the thorax. Mention of angular measurements of the axis of the heart could be found only in the text-books of Testut and Luschka; the former gives 40° to the horizontal plane, the latter 60° to the mid-sagittal. Luschka's angle appear to be too large; but further investigation in this direction is desirable.
Incisura apicis cordis
Size and weight. — In the adult the heart measures about 12.5 cm. (5 in.) from base to apex, 8.7 cm. (31 in.) across where it is broadest, and 6.2 cm. (24 in.) at its thickest portion. In the male its weight averages about 312 gm. (eleven ounces), and in the female about 255 gm. (nine ounces). It increases both in size and weight up to advanced life, the increase being most marked up to the age of twenty-nine years. The proportion of heart-weight to body-weight is about 1:205 in the adult.
In hearts which have been hardened by injection before removal from the bod}^, the regularity of the heart-cone is disturbed by a well-marked triangular facet, imparted by contact with the diaphragm. This facet is the diaphragmatic surface [facies diaphragmatica], which is directed downward and slightlj- backward (fig. 424). It ends abruptly along a sharp margin extending from the apex
toward the right. This margin is the margo acutus (fig. 423) ; it separates the diaphragmatic surface from the sternocostal surface. The other margin of the diaphragmatic surface is more rounded and shades gradually into the very wide margo obtusus (fig. 423), which passes almost insensibly into the sternocostal surface. The convex sternocostal surface [facies sternocostalis] (fig. 423), directed forward and somewhat upward and to the right, is triangular and bounded below by the margo acutus. To the left it goes over into the margo obtusus along a line extending from the apex of the heart to the root of the pulmonary artery. The margo obtusus corresponds to the rounded left side of the left ventricle.
The interventricular sulcus is a slightly marked groove indicating the separation of the ventricles upon the exterior of the heart. It lodges coronary bloodvessels and a moderate quantity of fat which can be seen through the epicardium.
The anterior part of this groove, sulcus longitudinalis anterior, beginning posteriorly, runs obliquely over the upper part of the margo obtusus on to the sternocostal surface. Crossing the margo acutus to the right of the apex, it is continuous with the sulcus longitudinalis posterior upon the diaphragmatic surface. The diaphragmatic surface is formed about equally by the right and left ventricles, and the sterno-costal surface mainly by the right. Where the longitudinal sulcus crosses the margo acutus it produces a slight notch, the incisura (apicis) cordis.
The atria are separated externally from the ventricles by the sulcus coronarius. This is a horseshoe-shaped groove well marked below and laterally, and interrupted above by the roots of the pulmonary artery and aorta. It lodges the coronary sinus, smaller coronary vessels and fat.
ATRIAL PORTION
The atrial portion of the heart is situated behind, and shghtly to the right of and above, the ventricular portion. The separation between the right and left atrium is not indicated behind except in distended hearts (such as that shown in fig. 424) ; in these it is marked by a slight groove connecting the left sides of the superior and inferior venae cavse. In front, the auricles are separated by the deep notch which lodges the aorta and pulmonary artery. A slight groove on the back of the right atrium which connects the right sides of the superior and inferior vense cavse, is the sulcus terminalis (figs. 424, 425) . This represents the right limit of what was, in the embryo, the sinus venosus. It also indicates that the embryonic sinus venosus has become an integral part of the adult right atrium. The superior and inferior cavae have each a nearly vertical direction and join the posterior part of the right atrium above and below, respectively. The coronary sinus runs downward, backward and to the right to join the lower part of the right atrium anterior to the inferior vena cava. The four pulmonary veins run nearly transversely and somewhat forward into the right and left sides of the left atrium.
Facies diaphragmatica
The interior of the atrial portion of the heart is divided into right and left cavities by the septum atriorum. This septum is a composite structure, having been developed (see morphogenesis of the heart) in two independent parts, each forming an incomplete septum in itself. The two incomplete septa, however, partly overlap one another so that, by the lateral fusion at the time of birth, they together produce the impervious structure of the adult heart (fig. 425). Of these septa, the first to be formed is the membranous septum [pars membranacea septi atriorum]. Later there is formed to the right of this the muscular septum, the margin of which forms, in the adult atrium, the greater part of the limbus fossae ovalis. The margin of the membranous septum is recognizable as a fold
foraminis ovjilis.
Posteriorly into the right atrium [atrium dextrum (fig. 425)], above and below, respectively, open the superior and the inferior vena cava. Upon the septal wall, immediately above the inferior cava is the fossa ovalis, a depression of
which the floor is formed by the membranous septum. Surrounding the fossa ovalis except below (indeed producing the fossa) is the limbus fossae ovalis which is continuous anteriorly and below with the valvula venae cavae (inferioris Eustachii). Just anterior to the fossa ovalis is the orifice of the coronary sinus guarded by the valvula sinus coronarii (Thebesii) (fig. 428). Leading from the
front of the atrium forward and slightly downward and to the left is the ostium venosum (right atrio-ventricular orifice) guarded by the tricuspid valve. Above and behind this is the auricle, the exterior of which is in contact medially with the root of the aorta. To the right of the superior and inferior caval orifices there is a vertical ridge, the crista terminalis, which corresponds to the sulcus terminalis on the exterior (figs. 425, 428).
The portion of the atrium medial to the crista is smooth and is called the sinus venarum; in the embryo it is separated from the atrial cavity proper by the right and left sinus valves. The crista terminalis marks the original line of attachment of the right sinus valve. The valve itself has disappeared, except at the lower part where it persists as the caval and coronary valves. These valves vary in size considerably in different specimens, and are frequently nethke from numerous perforations.
The conversion of a portion of a single valve into two separate valves, which meet at an acute angle, is brought about by an attachment between the sinus valve and an embryonic structure called the sinus-septum. This septum is a ridge dividing the right horn of the sinus venosus from the transverse portion of the sinus (the coronary of the adult) ; it probably con-
tributes somewhat to the formation of both the coronary and caval valves. The left sinus valve usually disappeai's by blending with the septum atriorum on which it unites with the limbus fossae ovalis; it ooeasionaUy remains partially separate in the adult.
The interior of the right auricle and of the portion of the atrium lateral to the crista terminalis is thrown into ridges (musculi pectinati) by prominent bands of the atrial myocardium. The musculi pectinati end abruptly by joining the crista. The orifice of the superior cava has no valve and is directed downward and somewhat forward; below it, on the posterior wall of the atrium, there has been described a tubercle or ridge, the tuberculum intervenostun (Loweri).
Apart from the posterior circumference of the superior cava itself and the limbus fossae ovalis, the hiunan heart appears to contain nothing in this region that could be described as a tubercle. With regard to the segregation of the streams entering the foetal right atrium from the superior and inferior cavae, respectively, in which the tubercle of Lower has been supposed to participate, it is to be noted that the fossa ovalis is just above (almost within) the inferior
caval orifice. Also that the caval opening and the fossal ovalis (containing the foetal foramen ovale) are, in hearts well hardened before removal, situated in a distinct diverticulum to the left of the remainder of the atrium. Between this diverticulum and the atrium proper, the caval valve and the limbus fossa? ovalis form a prominent flange, better marked in the foetus than the adult. Opening into the right atrium, particularly upon the septal and right lateral walls, are numerous /orowiraa venarum minimarum (Thebesii).
Part of posterior tricuspid cusp Posterior papillary
pulmonary root. Opening into it posteriorly on the right and left sides, respectively, are the right and left upper and lower pulmonary veins. The valvula foraminis ovalis forms a more or less distinct crescentic ridge on the septal wall (fig. 425). This may not be attached to the limbus fossas ovalis, in which case there is a communication between the two atria. Absence of lateral adhesion between the two septa atriorum does not necessarily lead to admixture of arterial and venous blood during life. The left ostium venosum (atrio-ventricular orifice)
guarded by the mitral valve leads from the anterior part of the atrium forward and shghtly downward and to the left. The interior of the left atrium is smooth except in the auricle, in which musculi pectinati are well marked.
The atrio-ventricular valves (figs. 427, 428, 429, 431) are attached around the venous ostia of the ventricles in such a way as to open freely into the ventricles, but to prevent regurgitation of the blood into the atria during ventricular systole. Each valve is continuous along its line of attachment, but its free edge is notched so as to produce an irregular margin; some of the notches are so deep as to partially divide the valve into cusps. The right atrio-ventricular valve is commonly divided by three deep notches into three cusps; this valve is therefore called the tricuspid [valvula tricuspidalis]. The left is similarly divided into two cusps and is called the bicuspid [v. bicuspidalis] or mitral. The depth of the notches, however, is very variable and there may be an increase or (more rarely) a diminution in the number of cusps; the addition of small subsidiary cusps is quite common. Each valve cusp is tied down to the papillary muscles [mm. papillares] of the ventricle by chordae tendinese. The latter are fibrous cords, generally branched, of varying thickness. The thinnest cords are attached to the free margin of the cusp; those of intermediate thickness to the ventricular surface a few millimetres from the margin, and the thickest to the ventricular surface
near the attached margin. The valves are smooth and glistening on the atrial aspect, but rough and fasciculated, from the attachment of the chordae, on the ventricular. The cusps of the mitral valve are called anterior and posterior; those of the tricuspid, anterior, posterior and medial. Each cusp receives chorda from more than one papillary muscle and each papillary muscle sends chordse to more than one cusp. The chordse tendinese of the mitral valve are thicker than those of the tricuspid (figs. 428, 429).
The ventricles form the greater portion of the heart. In the adult the relation of the ventricles to one another is as follows. The left [ventriculus sinister] has the form of a narrow cone, the apex of which is the apex of the heart. The right ventricle [ventriculus dexter] is crescentic in section and appears to be partially wrapped around the right or lower wall of the left ventricle which forms the septum ventriculorum (fig. 426). The left ventricle forms the margo obtusus of the heart, about half the diaphragmatic surface, and a shght part of the sterno-costal surface. The right ventricle forms about half the diaphragmatic surface and the major part of the sterno-costal surface; it takes no share in the formation of the apex of the heart.
The interventricular septum [septum ventriculorum] is thick and muscular except for a small area near the root of the aorta which is membranous [septum membranaceum ventriculorum]. The latter can be seen from the left ventricle in the angle between the attached edges of the right and posterior aortic valves (fig. 429). The membranous septum is partly concealed from the right heart by the medial cusp of the tricuspid valve which is attached to it near its upper part. The portion of the membranous septum above the medial tricuspid cusp is therefore atrio-ventricular, i. e., between the right atrium and left ventricle.
The membranous septum is the extreme lower part of the independent septum (s. aorticum) which divides the aortic root from the pulmonary artery and conus arteriosus (and partially subdivides, also, the right ventricle by separating the conus arteriosus from the remainder of the ventricle). The relation of the part of the aortic septum between the conus arteriosus and aortic root to the septum ventriculorum is beautifully shown by His, in fig. 427.
The greater part of the interior of the ventricles is thrown into ridges by myocardial bundles of large size. These fasciculi [trabeculae cordis] either stand out in rehef only, or, by being undermined, form bands covered except at either end by endotheUum. A careful examination of the endocardium of fresh hearts will reveal a plexiform network of Purkinje fibres. These fibres, belonging to the atrio-ventricular conducting system, become very obvious when the endocardium has been exposed to the air long enough to become partially dry.
The wall of the right ventricle [ventriculus dexter] (figs. 427, 428) is much thicker than that of the atria, but less so than that of the left ventricle. The upper and anterior part of the right ventricle is in relation posteriorly with the root of the aorta. This portion of the ventricle is called the conus arteriosus and is separated from the remainder of the right ventricle by a muscular spur which extends from the back of the conus to the right venous ostium. The spur is the crista supraventricularis ; its relation to the partition between the conus and aorta, and to the septum membranaceum, shows that it is the free edge of the embryonic aortic septum (see morphogenesis of the heart).
Two papillary muscles in the right ventricle are constant in position, the large anterior papillary muscle, and the small papillary muscle of the conus (Luschka). The anterior papillary is situated on the sterno-costal wall, near the junction of this with the septal wall. The papillary of the conus is placed just below the septal end of the crista supraventricularis. The posterior papillary muscles form an irregular group springing from the diaphragmatic wall. Some chordae tendinese stretch directly from the septal wall (with or without small muscular elevations at their bases) to the medial cusp of the tricuspid valve. The chordae tendinese from the anterior papillary go to the anterior and posterior cusps; those from the conus papillary to the medial and anterior, and those from the posterior papillary muscles to the medial and posterior cusps of the tricuspid valve, respectively.
There is frequently a band of myocardium extending from the septal wall of the right ventricle to the anterior papillary muscle near its middle. This is the moderator band, which contains a part of the right limb of the atrio-ventricular bundle. If the moderator band joins
ordinary trabeoulae in this situation.
The term moderator band was originally applied to this bridge or band of muscle under the impression that it prevented overdistention of the ventricle. Subsequent discovery of the conducting system of the heart makes it plain that there is always a band conducting the right limb of the atrio- ventricular bundle from the septum to the anterior papillary muscle. Whether the band is isolated from the other trabecules, and therefore readily recognizable, appears to depend somewhat upon the relation of the base of the papillary muscle to the septum ventriculorum.
The wall of the left ventricle [veiitriculus sinister] (figs. 427, 429) is very thick except at the extreme apex, and at the membranous septum. In the left ventricle are two large papillary muscles, generally known as anterior and posterior; both send chordae tendineae to each cusp of the mitral valve. On the septal wall of the ventricle the left limb of the atrio-ventricular bundle can usually be seen as a broad, flattened band beneath the endocardium. The band appears just below the septum membranaceum and divides into strands which go to the two papillary muscles. The strands in many places bridge across part of the ventricle to reach the papillary muscles covered only by tubes of endocardium.
These bridging strands connecting the papillary muscles with the septum ventriculorum, which were formerly called "false chordas tendinese," are exactly comparable to the moderator band of the right ventricle which occasionally consists of atrio-ventricular bundle and endocardium only.
SEMILUNAR VALVES
The semilunar valves [valvulse semilunares] guard the arterial ostia of the ventricles. The aortic ostium is directed upward and slightly forward and to the right; the pulmonary backward and slightly upward and to the left. Each valve, of which there are three to each ostium, is a pocket-like fold of endocardium strengthened by fibrous tissue (fig. 430) . The free edge of each valve is directed away from the ventricle, so that excess of pressure within the great vessels brings
Lunula
the three valves of either ostium into mutual apposition. In the middle of the free edge of each valve there is a small fibro-cartilaginous nodule; radiating from this toward the entire fundus, and along the extreme free edge of the valve, are fibrous thickenings. On either side of the nodule, between the thicker margin and fundus, the valve is thin over a crescentic area called the lunula.
The aortic valves are called the right, left, and posterior; the pulmonary valves, the right, left, and anterior.* The aortic semilunar valves are stronger than the pulmonary; opposite them there are three dilatations in the aortic wall, the aortic
* The BNA names of the aortic and pulmonary valves are not based upon their relative positions in the body. From transverse sections through the thorax (see any good atlas) it may be seen that one aortic valve is anterior, one pulmonary valve posterior, and the other aortic and pulmonary valves are right and left. If the removed heart is held so that the ventricles are on the right and left of the septum, respectively, the valves take the positions indicated by the BNA. The names given by the BNA to the valves, although conventional (Uke many other terms of orientation applied to parts of the heart), are convenient, particularly from a developmental standpoint.
right and left coronary arteries, respectively, arise.
After ventricular systole the increased pressure in the great vessels distends the valves with blood. The noduli meet in the centre and the lunulas, coming into mutual contact, produce a tri-radiate line of contact between the valves.
ARCHITECTURE OF THE MYOCARDIUM
In the adult heart the myocardium of the atria is separate from that of the ventricles. There is, between the atria and ventricles, a fibrous partition, the upper and lower surfaces ol which give attachment to the muscle fibres of these cavities, respectively.
The fibrous partition (fig. 431) is thickest in the triangle formed by the meeting of the aortic, and right and left atrio-ventricular ostia. This interval is filled by a mass of fibrous tissue, which in the angles between the aortic and the left atrio-ventricular ostium forms two thickened triangular masses, the trigona fibrosa. The fibrous mass is continued to the pulmonary ostium as the tendon of the conus. Below the point of junction of the trigona and the tendon of the conus these structures blend with the septum membranaceum ventriculorum. The septum membranaceum, tendon of the conus, and part of the trigona are derived from the aortic septum (pp. 516, 527). The trigona give off laterally, on either side, atrio-ventricular rings which encircle the venous ostia and give attachment to the atrio-ventricular valves. There are also weak
fibrosi.
The atrial musculature is attached to the trigona and atrio-ventricular rings only. The superficial fibres are attached to both rings and either encircle both atria in one loop, or enter the septum and form a figure 8. The deeper fibres are attached to one ring and encircle one atrium only; some fibres encircle only the auricle.
The ventricular musculature is very complex and consists of numerous superimposed layers distinguished from one another by the direction taken by the muscle fibres. In a general way, the fibres of the deepest layer have a direction crossing those upon the surface of the same area at a right angle. The intervening layers of fibres pass through all stages of obhquity.
1. AH fibres arise from, and are inserted into, the fibrous partition at the base. The attachment may be directly to the trigona or annuli, or indirectly to them by means of the chordse tendineae and atrio-ventricular valves.
2. The more superficial fibres (fig. 432) tend to encircle the entire heart, passing over the longitudinal sulci. If they enter the septum they do so by passing into the vorte.x or whorl at the apex of the left ventricle. These fibres have always a definite direction upon the surface, i. e., from right to left upon the sterno-costal surface and from left to right on the diaphragmatic (fig. 431).
3. The deeper fibres all enter the septum in a direction oblique or perpendicular to its longitudinal axis. In addition they completely encircle one or both ventricles forming, in the latter case, double loops (fig. 433).
VESSELS AND NERVES OF THE HEART
During systole, as a result of this arrangement: — (1) The papillary muscles and the longitudinal and antero-posterior axes of the ventricles are simultaneously shortened. (2) There is a movement of torsion or "wringing" which I'educes the ventricular cavities to their minimum dimensions.
Conducting system. — Although the ordinary myocardium of the atria is distinct from that of the ventricles there is, at one place, a connection between them. This connection is by means of a small band of muscle which differs histologically from ordinary heart muscle. It is known as the atrio-ventricular bundle, and serves to transmit the atrial rhythm of contraction to the ventricles.
The atrio-ventricular bundle begins in the septal wall of the atrium a short distance in front of the coronary orifices (fig. 428). It has an e.xpanded free end, the atrio-ventricular node, from which branches pass to be quickl}' lost in the atrial myocardium. The bundle passes forward covered by endocardium and by one or two millimetres of mj'ocardium, and passes beneath the medial cusp of the tricuspid valve. In passing from the atrium to the ventricle, the bundle skirts the lower margin of the septum membranaceum. Immediately in front of the septum membranaceum it divides into a left and right limb, of which the former pierces the muscular interventricular septum . The right limb now passes beneath the crista supra ventricularis and above the papillary muscle of the conus, giving off branches to the latter and to other small papillaries on the septum (fig. 428). Bending somewhat toward the apex, it enters the moderator band which conducts it to the large anterior papillary muscle. From here it passes along one of the trabeculae connected with the sterno-oostal wall of the ventricle, or in the wall itself, to reach the posterior papillary muscle or muscles. The right limb is compact and rounded and in the intact heart is usually invisible except, sometimes near the root of the moderator band or in the band itself.
branaceum. It is a wide band immediately beneath the endocardium, which cannot usually be
Fig. 432. — Diagram of one Anterior AND ONE Posterior Superficial Bundle OP Cardiac Muscle Fibres seen from Behind. (After MacCallum.)
stripped off without injuring the bundle (fig. 429). It passes along the septal wall toward the apex and divides into two parts, which again subdivide to be distributed to the anterior and the posterior papillary muscles. The branches for the papillary muscles may reach them through thick trabecula;, or they may form thin strands which, covered only by endocardium, bridge from septum to papillary muscle.
In addition to the comparatively distinct branches to the papillary muscles of both ventricles, the bundle gives off finer fibres which form a sub-endocardial plexus. This plexus, visible to the naked eye (p. 516) is made up of fibres having a structure similar to those of the ventricular portion of the bundle. The fibres were described by Purkinje as long ago as 1845,* but it was not until 1906, thirteen years after the discovery of the bundle by W. His, Jr., that Tawaraf recognised their significance.
There is another node of muscle having characters similar to that of the conducting system, although not connected with it except by myocardium of the ordinary character. This is the sinus-node which is situated at the upper end of the crista terminaUs of the right atrium. Unanimity is still lacking with regard to the physiological significance of this structure.
The right coronary artery [a. coronaria dextraj passes forward between the pulmonary artery and the right atrium, and then follows the right coronary sulcus to the diaphragmatic surface of the heart (fig. 435), to anastomose with the left coronary artery. The posterior descending branch [ramus descendens posterior] arises at the posterior longitudinal sulcus. It
E asses in the furrow between the ventricles toward the apex, near which it anastomoses with ranches derived from the left coronary artery. In this course the right coronary artery supplies branches to the right atrium and roots of the pulmonary artery and aorta, as well as one that descends near the margo acutus (right marginal), and a second (preventricular) to the anterior wall of the right ventricle. It supplies both ventricles and the septum.
The left coronary artery [a. coronarius sinistra] passes for a short distance forward, between the pulmonary artery and the left auricle, and then divides into two principal branches, one of which runs in the anterior longitudinal sulcus to the apex of the heart, the anterior descending branch [r. descendens anterior], around which it sends branches to anastomose with the right coronary; whilst the other, the circumflex [ramus circumflexus], winds to the diaphragmatic surface in the coronary groove, to anastomose with the corresponding twigs of the right artery. In this course it gives off a branch which follows the margo obtusus (left marginal) as well as smaller branches to the left atrium, both ventricles, and the commencement of the aorta and pulmonary vessels.
the walls of the heart.
The great cardiac vein [v. cordis magna], (fig. 434) runs in the anterior longitudinal sulcus, passing round the left side of the heart in the coronary sulcus to terminate in the commencement of the coronary sinus. Its mouth is usually guarded by two valves, and it receives in its course the posterior vein of the left ventricle, with other smaller veins from the left atrium and ventricle, all of which are guarded by valves.
The middle cardiac vein (v. cordis media], sometimes the larger of the two chief veins, communicates with the foregoing at its commencement above the heart's apex. It ascends in the posterior longitudinal groove, receiving blood from the ventricular walls, and joins the coronary sinus through an orifice guarded by a single valve, close to its termination.
in the coronary sinus.
The anterior cardiac veins [vv. cordis anteriores] consist of several small branches from the front of the right ventricle, which vary in number and either open separately into the right atrium or join the lesser cardiac vein (fig. 434).
The small cardiac vein [v. cordis parva] is a small vessel which receives branches from both the right atrium and ventricle, and winds around the right side of the heart, in the coronary sulcus, to terminate in the coronary sinus.
The coronary sinus [sinus coronarius] (fig. 435) may be regarded as a much dilated terminal portion of the great cardiac vein. It is about 2.5 cm. (1 in.) in length, is covered by muscular fibres from the atrium, and hes in the coronary sulcus below the base of the heart. Its cardiac orifice, with the coronary (Thebesian) valve, has already been described. Besides the tributary veins already named, a small oblique vein [v. obUqua atrii sinistri] of the left atrium may some-
times be traced, on the back of the left atrium, from the ligament of the left vena cava (Marshall) to the sinus. This httle vein, which is not always pervious or easy of demonstration, never possesses a valve at its orifice, and, Uke the coronary sinus, formed a part of the left superior vena cava of earlyfoetal life.
right atrium.
Although anastomoses occur between the two coronary arteries, these are by no means extensive, and are not sufficient to allow of the estabhshment of a satisfactory collateral circulation in the case of the blocking of one coronary artery. Consequently such interference with the cardiac circulation produces rapid pathological changes in the heart musculature, provided it is sudden in occurrence. If the obhteration of the artery take place gradually, however, some rehef may be afforded by the estabhshment of a collateral circulation through the vense minimse, which open out from both the atrial and ventricular cavities and communicate
The cardiac nerves, derived from the vagus and the cervical sympathetic, descend into the superior mediastinum, passing in front of and behind the arch of the aorta; they unite in the formation of the superficial and deep cardiac plexuses. The superficial plexus lies above the right pulmonary artery as the latter passes beneath the aortic arch. The deep plexus lies between the trachea and the arch of the aorta, above the bifurcation of the pulmonary trunk. For the connections of the plexuses see section on Nervous System.
2. THE PERICARDIUM
The pericardium is a cone-shaped, fibro-serous sac which surrounds the heart and contains a small amount of fluid [liquor pericardii]. Its apex is above at the root of the great vessels, and its base below, adherent to the diaphragm. Its connection with the diaphragm is in part to the central tendon and in part to the muscle, especially on the left side. It consists of an outer fibrous layer and an inner serous layer. The virtual space between the serous pericardium and the epicardium is commonly called the pericardial cavity.
Vena cava inferior
The fibrous layer is strong and inelastic, made of interlacing fibres. Its connection with the central tendon of the diaphragm is intimate, particularly in the region of the caval opening, but elsewhere it is attached loosely by means of areolar tissue. Above, it is lost on the sheaths of the great vessels, all of which receive distinct investments, with the single exception of the inferior vena cava, which pierces it from below. The aorta, superior vena cava, the pulmonary artery, and the four pulmonary veins, are all ensheathed in this manner. The pericardium is connected above with the deep cervical fascia. Two variable bands of fibrous tissue, the sterno-pericardial ligaments [ligg. sterno-pericardiaca], connect the front of the pericardium, above and below, with the posterior surface of the sternum.
RELATIONS OF HEART AND PERICARDIUM 523
The serous layer is smooth and ghstening and consists of connective tissue, rich in elastic fibres, covered by endotheUum. It lines the interior of the fibrous layer and is continuous with the epicardium or serous covering of the heart. The reflexion of the serous layer from the heart to the fibrous layer of the pericardium occurs at both the arterial and venous attachments of the heart. At the arterial attachment a simple tube of epicardium is reflected along the pulmonary artery and aorta. At the venous attachment the serous layer is reflected from the front of the pulmonary veins on the left, and from the front of these and from the roots of the venae cavae on the right. This reflexion is separated above from that around the aorta and pulmonary artery (figs. 424, 436). Around the lower margin of the left lower pulmonary vein (fig. 436) and the root of the inferior vena cava, this reflexion is continuous with an arched refle.xion from the back of the atria (figs. 424, 436). The latter reflexion forms a pocket posterior to the atria which is sometimes called the oblique sinus of the pericardium.
Between the reflexions of the epicardium at the arterial and venous attachments of the heart there is a dorsal communication between the right and left sides of the pericardial cavity. This is the transverse sinus of the pericardium [s. transversus pericardii]; it passes behind the aorta and pulmonary artery and in front of the superior cava and left atrium.
During early embryonic life the sinus transversus is closed by the dorsal mesocardium (see p. 527). The primitive ventral mesocardium, which divides the right and left sides of the pericardial cavity ventrally, is lost very early.
The ligament of the left superior cava [lig. vense cavae sinistrse] (figs. 423, 436) is a doubling of the serous layer which passes between the left pulmonary artery above and the left superior pulmonary vein below. It contains, besides some fatty and areolar tissue, the shrunken remains of the left superior vena cava. It is usually connected above with the left superior intercostal vein by means of a small tributary of the latter. Passing from its lower end to the left end of the coronary sinus is the small vena obliqua atrii sinistri (oblique vein of Marshall). The root of the left superior intercostal (and the adjacent part of the left innominate) vein; the vein passing from the super or intercostal to the lig. venae cavae sinistrse; the obhque vein of the left atrium, and the coronary sinus all represent parts of the embryonic left vena cava superior.
Relations. — In front of the pericardium are found the thymus gland or its remains, areolar tissue, the sterno-pericardial ligaments, the left transversus thoracis muscle, the internal mammary vessels, the anterior margins of the pleural sac and' lungs, and the sternum. Laterally, it is overlapped by the lungs with their pleural sacs, and it is in contact with the phrenic nerves and their accompanying vessels. Posteriorly, it is in relation with the cesophagus and vagus nerves, the descending aorta, the thoracic duct and vena azygos, and the roots of the lungs. Below it is separated by the diaphragm from the stomach and the left lobe of the fiver.
THORACIC WALL
Heart (fig. 437 A and B). — The base of the heart corresponds posteriorly to the fifth, to the ninth thoracic vertebra. Anteriorly the apex is in the fifth intercostal space, 7.5 to S cm. (3 to 3i in.) from the medan line. The base (above) corresponds to a line (A) drawn from a point 1 cm. (= in.) below the second left chondro-costal articulation, and 3 cm (Ij in. from the median line, to another point (the same distance from the median line) 1 cm. above the right third ehondro-sternal articulation. The marge acutus, or lower border corresponds to a line (B) drawn from the apex through the xiphi-sternal articulation, to a point on the sixth costal cartilage 2 cm. to the right of the median line. The right border of the heart may be indicated approximately by a fine (shghtly convex to the right) joining the right ends of A and B. The left border corresponds to a fine (slightly convex to the left) joining the left end of A to the apex.
If a line be drawn from the upper margin of the left third ehondro-sternal articulation to the right edge of the sternum in the fifth intercostal space, the upper end of the line wiU he over the centre of the pulmonary ostium, and the lower two-thirds of it (approximateljO will overlie the main axis of the tricuspid ostium. The aortic ostium is immediately to the left of the above line with its centre at the left edge of the sternum opposite the third space. The mitral ostium is very largely behind the third left interspace; its upper end is behind the third cartilage, its lower behind the left margin of the sternum opposite the fourth cartilage and space.
slightly in advance of the mitral, and the tricuspid is the deepest of all.
The pericardium follows the heart closely. The upper end (apex) in the subject used in preparing fig. 437 extended up, behind the sternum, to the lower margin of the first costal cartilage on the right and the upper margin of the second on the left.
The heart is formed by the blending in the median fine of two longitudinal endothehal tubes lying ventral to the fore-gut of the early embryo. Each tube is partially surrounded laterally by the splanchnic mesoderm which forms a septum between the right and left sides of
Fig. 437. — A, Telebobntgenogham of a Formalin Preparation or the Anterior Thoracic Wall with the Heart, Pericardium and Diaphragm in situ. (Le Wald, X i). B, Explanatory Outline Drawing, Traced from the Negative and Controlled BY Stereoscopic Views.
the ccelomic cavity. The blended endothehal tubes form the endocardium. The splanchnic mesoderm in relation to the endocardium becomes the myoepicardium, and the double layer connecting the heart dorsally and ventrally with the somatic mesoderm becomes the (temporary) dorsal and ventral mesocardia. The somatic mesoderm of the heart region becomes the pericardium.
The originally straight heart-tube grows rapidly and becomes tortuous on account of its increasing length between the hmits assigned by its fixed arterial and venous ends. Its arterial end is continued into the truncus arteriosus, which is later divided into the pulmonary artery and the ascending aorta. Its venous end receives the vitehine and umbihcal veins, and, later on, the common cardinals also. By the formation of a series of alternate bulgings and constrictions the heart becomes differentiated into the sinus venosus, atrium, ventricle and conus arteriosus, counting from the venous to the arterial end. These parts, after going through a process of progressive differentiation and shifting (fig. 438) take up relative positions somewhat approaching those of the adult.
Conus arteriosus Conus arteriosus
The sinus venosus hes on the dorsal wall of the atrium, and is composed of right and left horns united by a transverse portion. The sinus is separated from the atrium by a sagitaUy directed sHt-Uke opening, guarded by right and left lateral valves which project into the atrium. The atrium is wide, being prolonged into a ventrally projecting pouch on either side, the future right and left auricles. The ventricle is situated caudal and somewhat ventral to the atrium. The right Umb of the common ventricle, which leads into the conus arteriosus, is the future right ventricle; the left limb, connected with the atrium, is the future left ventricle. The
Sinus venosus
communication between the atrium and the ventricle, known as the atrial canal, is indicated on the exterior by a constriction; its interior consists of a transversely placed slit. The conus arteriosus is continued from the ventricle without obvious constriction and passes over into the truncus arteriosus.
The sinus venosus early loses its bilateral symmetry owing to the rapid enlargement of the right horn. This horn soon receives, through the proximal portion of the right vitelline vein {inferior vena cayo), all the blood coming from the left vitelline and both umbihcal veins. The right common cardinal also gains ascendency over the left and becomes the superior vena cava.
The left horn and transverse part, now only draining the dwindling left common cardinal, (left superior cava) and the coronary veins, become the coronary sinus. The right horn gradually becomes absorbed into the right end of the atrial cavity until the superior and inferior cava; and the coronary sinus acquire separate openings into that chamber. Between the opening of the coronary sinus and that of the inferior cava there is a ridge, the sinus-septum (between the right horn and transverse parts of the sinus), which becomes attached to the lower part of the right sinus valve.
In the atrium a septum begins early to grow from the ventro-cephaUc wall of the atrium, toward the atrial canal. As the interatrial communication around the edge of the septum (ostium primum) is becoming narrow, a perforation occurs near the attached margin of the septum (ostium secundum). This fii-st septum (septum primum) is incomplete because when its edge reaches the atrial canal the atria stiU communicate through ostium secundum. To the right of the septum primum another septum (s. secundum) is formed later; this never stretches completely across the atrium and is rather a crescentic ridge than a true septum. Until the free edges of the two septa overlap one another there is a direct passage leading from one side of the atrium to the other; eventually they do overlap and the communication becomes oblique but persists until birth. (For adult relations of septa, see p. 511.) The cavities resulting from the division of the common atrium are the right and left atria of the adult. The obUque channel connecting the atria (foramen ovale) is bounded on the right side by the s. secundum the free edge of whicli forms the limbus fossae ovalis. The channel is bounded on the left by the s. primum which slants into the left atrium. The free edge of the s. primum becomes the valvula foraminis ovalis; the remainder, the membranous atrial septum of the adult.'
The lower part of the ventricular portion has been cut off. Connective tissue septa colored yellow. Ao, aorta; Ap, anterior papillary muscle; La, left atrium; Lo, left venous ostium; Lp, large (anterior) papillary muscle of right ventricle; Mpm, medial papillary muscle; PP, posterior papillary muscle; P, pulmonary artery; RA, right atrium.
The portion of the dorsal wall of the right atrium immediately adjoining the septa is derived from the sinus venosus. Tliis part of the atrium (the sinus venarum) receives the great venous openings. The left side of the left sinus-valve is attached to both septa and assists the septum secundum in the formation of the limbus foraminis ovalis. The cephalic part of the right sinusvalve disappears along the line of the (adult) crista ierminalis, which therefore hmits the right portion of the right atrium derived from the sinus venosus. The caudal portion of this valve persists as the inferior caval and coronary valves. These are drawn out of their original ahgnment by the adhesion between the caudal part of the right sinus-valve and the sinus-septum.
The left atrium receives, through the dorsal mesocardium, the originally single pulmonary vein. This common stem is absorbed into the atrial wall; later, the primitive right and left tributaries are absorbed in a similar way, leaving the four pulmonary veins of the adult opening separately into the left atrium. The area of the left atrium adjacent to the pulinonary veins, therefore, is not part of the original atrial waU.
The ventricles are divided by a septum (s. musculare ventriculorum) growing from the caudal wall of the common ventricular cavity toward the atrial canal. The canal moves to the right, and the dorsal part of the septum blends with the dorsal lip of the canal. The free ventral edge of the interventricular septum helps to bound the foramen through which blood from the left ventricle must enter the right on its way to the conus arteriosus. The foramen persists until (the free margin of the interventricular septum having been joined by the aortic septum) it becomes the circumference of the aortic ostium.
THE ARTERIES AND VEINS 527
The aortic septum is a composite structure formed partly by a septum growing between tlie fourth and sixth pairs of aortic arches, and partly by sweUings growing in the interior of the conus and truncus arteriosus. When fully formed it extends spirally along the truncus and conus, and enters the right half of the common ventricular cavity, where it joins the right side of the free edge of the interventricular septum. The septum is arranged in such a way that the blood from the left ventricle passes no longer through the right ventricle but along its own channel {the aorta) through the conus and truncus to the first four pairs of aortic arches. The blood from the right ventricle passes through the pulmonary division of the conus and truncus arteriosus, anterior and to the left of the aorta, into the sixth arches. Further differentiation brings about the external separation of the aorta from the pulmonary artery, but their common covering of epicardium persists as such in the adult. The lower end of the aortic septum persists in the adult as the septum membranaceum ventriculorum and the crista supraventricularis, the relations of which to the septum musculare are well shown in fig. 428. During the formation of the aortic septum four endocardial swelhngs appear at the distal part of the interior of the conus. These are arranged as smaller and larger opposite pairs; the smaller and larger swellings, therefore, alternating around the lumen. The larger pair of swellings assists (by partial blending) in the formation of the aortic septum. When the septum is complete, half of each of the larger sweUings is contained in the aorta and half of each in the pulmonary artery. One of the smaller swelhngs remains in the aorta and one in the pulmonary artery, so that there are now three sweUings in each vessel. Each of the six swellings becomes undermined to form a semilunar valve of the adult.
The atrio-ventricular valves. — The interior of the ventricular cavity, which is at first smooth, becomes undermined in an irregular way, to form a system of myocardial trabeculse. The Ups of the transversely directed atrial canal become thickened into prominent anterior and posterior endocardial cushions; these project into the ventricular cavity and become involved in its myocardial trabecular system. The atrial canal, which has now moved to the right, becomes divided sagittaUy, into right and left venous osiia, by the septum primum. The interventricular septum joins the ventricular side of the posterior endocardial cushion. The anterior and posterior endocardial cushions, where they blend with one another and with the septum primum on the medial side of each venous ostium, form an atrio-ventricular valve-cusp on either side, viz., the anterior cusp of the mitral in the left ostium, and the medial cusp of the tricuspid in the right. The posterior cusp of the mitral and the anterior and posterior of the tricuspid are formed later, partly, by lateral tubercles developing in either ostium, and partly by undermining of the ostia from the ventricular side. The atrial musculature extends into the atrio-ventricular valves and, until a late stage, is continuous with the trabecular system of the ventricles. GraduaUy, however, this connection between atrial and ventricular musculature is lost, leaving only the chordae tendinese connecting the papillary muscles with the valves Muscle is found at the basal region of the valve-cusps in the adult, and occasionally persists in the chordae tendinese.
The connection between the atrial and ventricular musculature is not confined to that occurring by means of the valves and trabecular system. The original myocardial connection between the atrial and ventricular portions of the heart remains complete until the embryo has reached the length of about 11 mm. From that time on the epicardium begins to blend with the fibrous annuh of the venous ostia. MeanwhUe the atrial musculature rapidly loses its connection with that of the ventricles until they are connected in one place only, i. e., the site of the atrio-vetitricular bundle.
The pericardial cavity is the original cephalic end of the intraembryonic ccelom. The somatic mesoderm of the pericardial region forms the adult pericardium. The splanchnic mesoderm persists only in the part which furnishes the myo-epicardium. The ventral and dorsal mesocardia, both of which are formed by the splanchnic mesoderm, are, in the main, transitory. The early disappearance of the ventral mesocardium unites the right and left sides of the pericardial ccelom ventral to the heart. The dorsal mesocardium persists at the arterial and venous ends of the heart only. The loss of the dorsal mesocardium between the latter points gives rise to the sinus transversus pericardii of the adult.
During development, the heart and pericardium migrate from a point opposite the cephahc end of the pharynx to one opposite the caudal end of the oesophagus; in fact, from the neck well into the thorax. In the adult, instead of being at the cephahc end of the ccelom, the heart and pericardium are contained between the right and left layers of the ventral mesentery of the oesophagus; the pericardial pleura of the adult.
The arteries [arteriae], proportionately to their size, have much thicker walls than the veins. After death they retain their natural form, but are contracted and contain usually a small amount of pale clot. In a very general way the thickness of wall is proportional to cahbre. Some arteries, however, are constantly thicker or thinner than could be predicted from size alone.
The larger arteries usually take a direct course and branch dichotomously. In descriptive anatomy if dichotomous branches are of nearly equal size it is common for each to take another name; if one branch preponderates in size, it is apt to retain the name of the parent trunk while the smaller is regarded as a collateral branch [vas coUaterale] . There are numerous
There is less tendency to anastomosis between large or medium sized arteries than in veins of corresponding magnitude. Anastomoses do occur, however, particularly in the form of arches, such as the palpebral, plantar and volar arches, or the arches between the intestinal arteries. This form of anastomosis is sometimes called inosculation. Between smaller arteries anastomosis is usually free as in the case, for instance, of the articular retia. In some organs anastomosis (excepting capillary) between neighbouring arteries can scarcely be said to exist at all; the a. centralis retinae affords a good example of this, as do the arteries of the brain, spleen, and kidney; such arteries are called terminal.
branches.
The veins [venae] have thin walls, and after death are either collapsed or filled with clot or stained serum. They are characterized by the presence of valves and frequent anastomoses.
Frequent anastomoses occur between veins of all sizes; plexuses are common, such, for instance, those of the pelvis. Venm comitantes are veins which, usually in pairs, accompany many arteries; they communicate with one another, around the artery, very freely. Veins do not primitively accompany arteries. In the case of the extremities the primitive veins are superficial. The deep veins of the hmbs are of later formation and to them the superficial veins subsequently become tributary.
The veins from the stomach, spleen, pancreas and intestine are collected into a large trunk, the portal vein. This does not open into the inferior vena cava directly, but breaks up into numerous smaller vessels in the Hver. From these the blood is returned, through the hepatic veins, to the inferior cava.
Many veins are provided with valves, the free borders of which are directed toward the heart. In the small veins the valves are single; in the larger veins they are usually double, rarely treble. Valves are much more numerous in the veins of infants than those of the adult, they seem to disappear progressively with advancing age. The venous valves are most numerous in the superficial veins, and in the deep veins of the extremities; in many veins of the head and neck they occur only at their point of termination in a larger trunk.
The cranial venous sinuses are modified veins, consisting of intima only which lines channels in the fibrous dura mater. The venous spaces in cavernous tissue, such as the corpora cavernosa, may be looked upon as specially modified veins.
The larger veins, hke the arteries, have vasa vasorum.
The arteries and veins will be considered in the following order: 1, pulmonary artery and veins; 2, the systemic arteries; and, 3, the systemic veins. At the ends of the second and third divisions, the development and variations are considered.
1. THE PULMONARY ARTERY AND VEINS
The pulmonary artery [a. pulmonahs] (fig. 441) passes from the right ventricle to the lungs. It differs from all other arteries in the body in that it contains venous blood. It arises as a short, thick trunk from the conus arteriosus of the right ventricle, and, after a course of about 5 cm. (2 in.) within the pericardium, divides into a right and a left branch. These branches pass to the, right and the left lung respectively.
The trunk of the pulmonary artery at its origin is on a plane anterior to the ascending aorta, and slightly overlaps that vessel. Thence it passes upward, backward, and to the left, forming a slight curve around the front and left side of the ascending portion of the aorta; and, having reached the concavity of the aortic arch, on a plane posterior to the ascending aorta, it divides into its right and left branches, which diverge from each other at an angle of about 130°. The division of the pulmonary artery occurs immediately to the left of the second left chondrosternal articulation.
In the foetus, the pulmonary artery continues its course upward, backward, and to the left under the name of the ductus arteriosus (Botalli), and opens into the descending aorta just below the origin of the left subclavian artery. After birth, that portion of the pulmonary artery which extends to the aorta becomes obhterated, and remains merely as a fibrous cord, the ligamentum arteriosum (fig. 436).
Relations. — In front, the trunk of the pulmonary artery is covered by the remains of the thymus gland, and the pericardium. The artery Ues, at its commencement, behind the upper margin of the third left chondro-sternal articulation. The right margin of the artery is behind the second piece of sternum but the greater part of the vessel is behind the medial end of the second intercostal space.
artery, and the cardiac nerves.
The right pulmonary artery [ramus dexter] longer than the left, passes almost horizontally under the arch of the aorta to the root of the right lung, where it divides, either directly or after repeated division, into three branches, one for each lobe. These branches follow the course of the bronchi, dividing and subdividing for the supply of the lobules of the lung. The terminal branches do not anastomose with each other.
Relations. — In its course to the lung it has in front of it the ascending aorta, the superior vena cava, the phrenic nerve, the anterior pulmonary plexus, and the reflexion of the pleura. Behind are the right bronchus and the termination of the azygos vein. Above is the arch of the aorta, and below are the left atrium and the upper right pulmonary vein.
At the root of the lung it has the right bronchus above and behind it; the pulmonary veins below and in front. Crossing in front of it and the other structures forming the root of the lung are the phrenic nerve and the anterior pulmonary plexus; behind are the azygos vein, the vagus nerve, and the posterior pulmonary plexus.
The left pulmonary artery, shorter and slightly smaller than the right, passes in front of the descending aorta to the root of the left lung, where it divides into two branches for the supply of the upper and lower lobes respectively. These divide and subdivide as on the right side.
Relations. — At the root of the lung it has the left bronchus behind and also below it, in consequence of the more vertical direction taken by the left bronchus than by the right. Below and in front are the pulmonary veins, while passing from the artery and the upper left pulmonary vein is the hgament of the left superior cava. Crossing in front of it and the other structures forming the root of.the lung are the phrenic nerve, the anterior pulmonary plexus, and the reflexion of the left pleura; crossing behind, are the descending aorta, the left vagus nerve, and the posterior pulmonary plexus.
The pulmonary veins [vv. pulmonales] (figs. 424, 441) return the aerated blood from the lungs to the heart. They are usually four in number, superior and inferior, of the right and left sides. Occasionally, however, there are three pulmonary veins on the right side, the result of the vein from the middle lobe of the right lung opening separately into the left atrium instead of joining as usual the upper of the two right pulmonary veins. The relations of the pulmonary veins to the pulmonary arteries and bronchi in the lungs- are given with the anatomy of the lungs (Section X).
The pulmonary veins are about 15 mm. in length. In the pericardium the right pulmonary veins [vv. pulmonales dextrse] both pass behind the superior vena cava. The superior vein receives the vein from the right middle lobe and runs below and in front of the right pulmonary artery.
The aorta (fig. 442) is the main systemic arterial trunk, and from it all the systemic arteries are derived. It begins at the left ventricle of the heart, and ascends near the anterior thoracic wall as high as the second right chondro-sternal articulation [aorta ascendens]. It then turns backward and to the left forming an arch [arcus aortas] which reaches the posterior thoracic wall at the left side of the fourth thoracic vertebra. From here it runs downward along the vertebral column [aorta descendens] through the thorax and abdomen and ends by dividing, opposite the fourth lumbar vertebra, into the right and left common iliac arteries. From the point of bifurcation a small vessel, the middle sacral, is continued down the middle line in. front of the sacrum and coccyx. The midclle sacral represents the sacral and coccygeal aorta.
the sternum to the upper border of the right second chondrosternal articulation. It measures about 5 to 5.5 cm. (2 to 2i in.), forming, as it ascends, a gentle curve with its convexity to the right. It is enclosed for the greater part of its length in the pericardium, being invested, together with the pulmonary artery, in a common sheath formed by the serous layer of that membrane. A dilatation known as the bulbus aortse occurs immediately above the heart upon which are three locaHzed bulgings, known as the aortic sinuses (sinuses of Valsalva); they are placed, one to the right, one to the left, and one posteriorly. From the right and eft are derived the coronary arteries of the heart. (See Heart.)
Relations. — In front, it is overlapped at its commen-cement by the right auricle, conut arteriosus and pulmonary artery. Higher up, as the pulmonary artery and auricle diverge, is is separated from the manubrium by the pericardium, the remains of the thymus gland, and by the loose tissue and fat in the superior mediastinum, and is here shghtly overlapped by the right pleura and by the edge of the right lung in full inspiration. The root of the right coronary artery is also in front.
second right costal cartilage to the lower border of the fourth thoracic vertebra. Attached to the concavity of the arch, just beyond the origin of the left subclavian artery, is the ligamentum arteriosum (vestige of the dorsal part of the left sixth arch). Between the left subclavian artery and the ligamentum arteriosum there is sometimes a definite constriction of the arch (isthmus aortse) situated opposite the third thoracic vertebra. When the isthmus is well marked, it is succeeded by a dilatation (aortic spindle) which begins in the neighbourhood of the ligamentum arteriosum and passes over into the descending aorta. Passing under the arch are the left bronchus, the right pulmonary artery, and the left recurrent (inferior laryngeal) nerve. It measures about 4.5 cm. (14- in.).
and to a greater extent by the left pleiu-a and lung. It is crossed in the following order from right to left, by the left phrenic nerve, by the cardiac branches of the vagus nerve, the cardiac braUches of the sympathetic nerve, by the left vagus nerve, and by the left superior intercostal vein as it passes up to the left innominate vein.
Below it — that is, in its concavity — are the bifurcation of the pulmonary artery, the left bronchus, the left recurrent (inferior laryngeal) nerve, the ligamentum arteriosum, the superficial cardiac plexus, two or more bronchial lymphatic glands, and the reflexion of the pericardium.
The branches of the aortic arch are: — the inDominate, the left common carotid, and the left subclavian arteries. The innominate and left carotid arise close together — indeed, so close that, when seen from the interior of the aorta, the orifices appear merely separated by a thin septum. The left subclavian arises a little less close to the left carotid.
THE INNOMINATE ARTERY
The innominate [a. anonyma] or brachio-cephalic artery (fig. 441), the largest branch of the arch of the aorta, extends from near its commencement upward and a little forward and to the right, as high as the upper limit of the right sterno-clavicular joint where it bifurcates into the right common carotid and right subclavian arteries. It lies obliquely in front of the trachea, and measures from -3.7 to 5 cm. (1| to 2 in.).
Pulmonary artery
Relations. — In front of the artery are the manubrium, the origins of the sterno-hyoid and sterno-thyreoid muscles, the right sterno-clavicular joint, and the remains of the thymus gland. The left innominate vein crosses the root of the vessel, and the inferior thyreoid and thyreoidea ima veins descend obliquely over it to end in the left innominate vein. The inferior cervical cardiac branches of the right vagus nerve pass in front of it on their way to the deep cardiac plexus.
The branches of the innominate artery are: — (1) The right common carotid; and (2) the right subclavian. These are terminal branches. There are usually no collateral branches from this vessel, but at times the thyreoidea ima may arise from it.
THE COMMON CAROTID ARTERY 533
The thyreoida ima artery, which occurs in about 10 per cent, of subjects, ascends on the front of the trachea to the thyreoid gland. It may be large in which case it might complicate the low operation of tracheotomy. It does not always arise from the innominate, but occasionally from the arch of the aorta (fig. 443) or from the right common carotid.
The common carotid arteries [aa. carotides communes] pass up deeply from the thorax on either side of the neck to about the level of the upper border of the thyreoid cartilage, where they divide into the external and internal carotid arteries. The external carotid supplies the structures at the upper part of the front and side of the neck, the larynx, pharynx, tongue, face, the upper part of the back of the neck, the structures in the pterygoid region, the scalp, and in chief part the membranes of the brain. The internal carotid gives off no branch in the neck, but enters the cranium and supplies the greater part of the brain, the structures contained in the orbit, and portions of the membranes of the brain.
The common carotid artery on the right side arises from the bifurcation of the innominate at the upper limit of the sterno-clavicular joint; on the left side from the arch of the aorta a little to the left of the innominate artery, and on a plane somewhat posterior to that vessel (fig. 441). The portion of the left common carotid artery which extends from the arch of the aorta to the upper limit of the sterno-clavicular articulation lies deeply in the chest, and requires a separate description; but above the level of the sterno-clavicular joint the relations of the right and left carotids are practically the same, and are given under the account of the right common carotid.
THORACIC PORTION OF THE LEFT COMMON CAROTID ARTERY
Within the thorax the left common carotid is deeply placed behind the manubrium of the sternum, and is overlapped by the left lung and pleura. It arises from the middle of the aortic arch, close to the left side of the innominate artery, and a little posterior to that vessel, and ascends obliquely in front of the trachea to the left sterno-clavicular articulation, above which its relations are similar to those of the right common carotid (fig. 442).
Relations. — In front, but at some httle distance, are the manubrium and the origins of the left sterno-hyoid and sterno-thyreoid muscles, whilst in contact with it are the remains of the thymus gland, and the loose connective tissue and fat of the superior mediastinum. Crossing its root is the left innominate vein.
The common carotid artery in the neck extends from the sterno-clavicular articulation to the upper border of the thyreoid cartilage on a level with the fourth cervical vertebra, where it divides into the external and internal carotid arteries. A line drawn from the sterno-clavicular joint to the interval between the mastoid process and the angle of the jaw would indicate its course. The artery is at first deeply placed beneath the sterno-mastoid, sterno-hyoid, and sterno-thyreoid muscles, and at the level of the top of the sternum is only 2 cm. (f in.) distant from its fellow of the opposite side, and merely separated from it by the trachea. As the carotid arteries run up the neck, however, they diverge in the form of a V and become more superficial, though on a plane posterior to that in which they lie at the root of the neck, and are separated from each other by the larynx and pharynx. At their bifurcation they are about 6 cm. (2j in.) apart. The common carotid is contained in a sheath of fascia common to it and the internal jugular vein and vagus nerve. The artery, vein, and nerve, however, are not in contact, but separated from one another by fibrous septa, which divide the common sheath into three compartments: one for the artery, one for the vein, and one
for the nerve. The vein, which is larger than the artery, lies to the lateral side, and somewhat overlaps it. The vagus nerve lies behind and between the two vessels. The artery on the right side measures about 9.5 cm. (3f in.) ; on the left side, about 12 cm. (4J in.) in length.
Relations. — In front the artery is covered by the skin, superficial fascia, platysma, and deep fascia, and is more or less overlapped by the sterno-mastoid muscle. At the lower part of the neck it is covered in addition by the sterno-hyoid and sterno-thyreoid muscles, and is crossed by the anterior jugular vein, and is often overlapped by the thyreoid gland. _ Opposite the cricoid cartilage it is crossed obliquely by the onio-hyoid muscle, and, above this spot, by the superior thyreoid vein, and the sterno-mastoid artery. Along the anterior border of the sterno-mastoid there is a communicating vein between the facial and anterior jugular veins, which, as it crosses the line of the carotid artery, is in danger of being wounded in the operation
of tying the carotid. The ramus descendens n. hypoglossi generally descends in front of the carotid sheath, being there joined by one or two communicating branches from the second and third cervical nerves. At times this nerve runs within the sheath. There are usually two lymphatic glands about the bifurcation of the artery. These are often found enlarged and infiltrated in cancer of the lip and tongue.
Behind, the common carotid lies on the longus colli and scalenus anterior below, and longus capitis (rectus capitis anterior major) above. Posterior to the artery, but in the same sheath, is the vagus nerve; and posterior to the sheath, the cervical sympathetic and the cervical
laryngeal nerve.
Medially, from below upward, are the trachea and oesophagus, with the inferior (recurrent) laryngeal nerve in the groove between them, and the terminal branches of the inferior thyreoid artery, the lateral lobe of the thyreoid gland, the cricoid cartilage, the thyreoid cartilage, and the lower part of the pharynx. At the angle of bifurcation is the carotid gland [glomus caroticumj.
overlaps the artery, thus leaving no interval corresponding to that on the right side.
The cricoid cartilage is, as a rule, taken as the centre of the incision in the operation for ligature of the common carotid artery. The incision is made in the line of the vessel parallel to the anterior margin of the sterno-mastoid muscle. The omo-hyoid forms one of the chief rallying points in the course of the operation for ligature of the artery above that muscle, the usual situation. The artery is found beating at the angle formed by the omo-hyoid with the sterno-mastoid.
Branches. — (1) External and (2) internal carotid arteries. The common carotid gives off no lateral branch, and consequently does not diminish in size as it runs up the neck. It is often a little swollen just below its bifurcation, a condition that should not be mistaken for an aneurismal dilation.
The collateral circulation (fig. 444), after Hgature of the common carotid, is carried on chiefly by the anastomosis of the internal carotid with the internal carotid of the opposite side through the circle of Willis; by the vertebral with the opposite vertebral; by the inferior thyreoid with the superior thyreoid; by the deep cervical branch of the costo-cervical trunk (superior intercostal) with the descending branch of the occipital; by the superior thyreoid, hngual, external maxillary (facial), occipital, and temporal, with the corresponding arteries of the opposite side, and by the ophthalmic with the angular. The anastomosis between the deep cervical branch of the costo-cervical trunk with the descending branch of the occipital is an important one; it is situated deeply at the back of the neck, and is to be found lying between the semispinaUs capitis (complexus) and cervicis muscles.
The external carotid artery [a. carotis externa] (fig. 445), the smaller of the two branches into which the common carotid divides at the upper border of the thyreoid cartilage, is distributed to the anterior part of the neck, the face, and the cranial region, including the skin, the bones, and the dura mater. It is at first situated medial to the internal carotid; but as it ascends in the neck it forms a gentle curve, with its convexity forward, and, running slightly backward as well as upward, terminates opposite the neck of the mandible just below the condyle, by dividing into the internal maxillary and superficial temporal arteries. It here lies superficial to the internal carotid, from which it is separated by a portion of the parotid gland. At its origin it is overlapped by the anterior margin of the sterno-mastoid, and is covered by the superficial fascia, platysma, and deep fascia. Higher up the neck it is deeply placed, passing beneath the stylo-hyoid muscle, the posterior belly of the digastric muscle, and the hypoglossal nerve; and finally becomes embedded in the parotid gland, where it divides into its terminal branches. It is separated from the internal carotid artery posteriorly by the stylo-pharyngeus and stylo-glossus muscles, the glosso-pharyngeal nerve, the pharyngeal branch of the vagus nerve, a portion of the parotid gland, and the stylo-hyoid ligament; or, if the styloid process is abnormaUy long, by that process itself. It measures about 6.5 cm. (2| in.).
Relations. — In front, in addition to the skin, superficial fascia, platysma, and deep fascia, it has the hypoglossal nerve, the hngual, common facial and posterior facial veins, the posterior belly of the digastric and stylo-hyoid muscles, the superior cervical lymphatic glands, branches of the facial nerve, and the parotid gland. The sterno-mastoid also overlaps it in the natural state of the parts.
Behind, it is in relation with the internal carotid, from which it is separated by the styloglossus and stylo-pharyngeus muscles, the glosso-pharyngeal nerve, the pharyngeal branch of the vagus nerve, the stylo-hyoid hgament, and the parotid gland. The superior laryngeal nerve crosses behind both the external and internal carotid arteries.
1. THE ASCENDING PHARYNGEAL ARTERY
The ascending pharyngeal artery [a. pharyngea ascendens] (fig. 446) is usually the first or second branch of the external carotid. Occasionally it comes off at the bifurcation of the common carotid from the common carotid itself. It is a long slender vessel which runs deeply seated up the neck to the base of the skull, having the walls of the pharynx and the tonsil medially, the internal carotid artery laterally, and the vertebral column, the longus capitis (rectus capitis anterior major), and the sympathetic nerve posteriorly. In front it is crossed by the stylo-glossus (fig. 446) and the stylo-pharyngeus muscles and the glossopharyngeal nerve.
The branches of the ascending pharyngeal artery are small and variable. They supply the longus and rectus capitis muscles, the upper cervical sympathetic ganglion and adjacent lymph-nodes, as well as the pharynx, soft palate, ear, cranial nerves, and meninges.
of the superior thyreoid. One branch (the palatine) passes over the upper edge of the superior constrictor to the soft palate and its muscles. This branch follows a course similar to that taken by the ascending palatine artery, and when the latter is small may take its place. It generally gives off small twigs to the Eustachian tube and tonsil. The inferior tympanic artery [a. tympanica inferior] accompanies the tympanic branch of the glosso-pharj'ngeal nerve through the tympanic canaliculus into the tympanum, and anastomoses with the other tympanic arteries. The posterior meningeal artery [a. meningea posterior] is distributed to the membranes of the brain. Some twigs pass with the jugular vein through the jugular foramen into the cranium, and supply the dura mater in the posterior fossa of the skull. Others occasionally reach the same fossa through the hypoglossal (anterior condyloid) canal in company with the hji^oglossal nerve; while others pass through the cartilage of the lacerated foramen and supply the middle fossa of the skull.
2. THE SUPERIOR THYREOID ARTERY
The superior thyreoid artery [a. thyreoidea superior] (figs. 445, 447) arises from the front of the external carotid a little above the origin of that vessel, and, coursing forward, medially, and then downward, in a tortuous manner, supplies the depressor muscles of the hyoid bone, the larynx, the thyreoid gland, and the lower part of the pharynx. The arterj' at first runs forward and a little upward, just beneath the greater cornu of the hyoid bone. In this part of its course it lies in the superior carotid triangle, and is quite superficial, being covered only with the integument, fascia, and platysma. It next turns downward, and passes beneath the omo-hyoid, sterno-hyoid, and sterno-thyreoid muscles, and ends at the upper part of the thyreoid gland by breaking up into terminal glandular branches. The superior thyreoid vein passes beneath the artery on its way to the internal jugular vein. The superior thyreoid is the artery most commonly divided in cases of suicidal wounds of the throat.
The named branches of the superior thyreoid artery are: — (1) The hyoid; (2) the sterno-mastoid; (3) the superior laryngeal; (4) the crico-thyreoid; (5) anterior; (6) posterior; and (7) glandular.
(1) The hyoid [ramus hyoideus] is usually a small twig which passes along the lower border of the hyoid bone, lying on the thyreo-hyoid membrane under cover of the thyreo-hyoid and sterno-hyoid muscles. It supplies the infra-hyoid bursa and the thjo-eo-hyoid muscle, and anastomoses with its fellow of the opposite side, and with the hyoid branch of the lingual. When the latter artery is small, the hyoid branch of the superior thyreoid is usually comparatively large, and vice versa.
(2) The sterno-mastoid [ramus sternocleidomastoideus] (fig. 447) courses downward and backward across the carotid sheath, and entering the sterno-mastoid supphes the middle portion of that muscle. It gives off slender twigs to the thyreo-hyoid, sterno-hyoid, and omo-hyoid muscles, and the platysma and integuments covering it. At times the vessel arises directly from the external carotid. It hes usually somewhere in the upper part of the incision for tying the common carotid above the omo-hyoid muscle.
BRANCHES OF THE LINGUAL ARTERY 539
thyreo-hyoid muscle, and, perforating the thyreo-hyoid membrane along with the internal branch of the superior laryngeal nerve, suppUes the intrinsic muscles and mucous lining of the larynx. Its further distribution within the larynx is given with the description of that organ. This branch sometimes arises from the external carotid direct. It may enter the larynx by passing through a foramen in the thyreoid cartUage.
(4) The crico -thyreoid [ramus cricothyreoideus] passes across the crico-thyreoid membrane immediately beneath the lower border of the thyreoid cartilage. It anastomoses with its fellow of the opposite side, and usually sends a small branch through the membrane into the interior of the larynx. Occasionally a considerable twig descends over the cricoid cartilage to enter the isthmus of the thyreoid gland. The crico-thyreoid has, however, frequently been seen of comparatively large size — once as large as the radial, and crossing the membrane obliquely. In order to avoid injuring the crico-thyreoid artery in the operation of laryngotomy, it is usual, if the operation has to be done in a hurry, to make the incision through the crico-thyreoid membrane in a transverse direction, and as near to the cricoid cartilage as possible.
the neighbouring part of the lateral lobe of the thyreoid gland.
(6) The posterior branch [ramus posterior], the other terminal, supplies the posterior part of the lateral lobe, and sends branches to the inferior constrictor of the pharynx and to the oesophagus. It anastomoses with the ascending branches of the inferior thyreoid artery.
3. THE LINGUAL ARTERY
The lingual artery [a. lingualis] (fig. 448) arises from tiie front of the external carotid, between the superior thyreoid and external maxillary (facial) arteries, often as a common trunk with the latter vessel, and nearly opposite or a little below the greater cornu of the hyoid bone. It may, for purposes of description, be divided into three portions: the first, or oblique, extends from its origin to the posterior edge of the hyo-glossus muscle; the second, or horizontal, lies beneath the hyo-glossus; the third, or ascending, beneath the tongue. The first or oblique portion is situated in the superior carotid triangle, and is superficial, being covered merely by the integument, platysma, and deep fascia. Here it lies on the middle constrictor muscle and superior laryngeal nerve. After ascending a short distance, it curves downward and forward beneath the hypoglossal nerve, and, in the second part of its course, runs horizontally along the upper border of the hyoid bone, beneath the hyo-glossus, by which it is separated from the hypoglossal nerve and its vena comitans, and the posterior belly of the digastric and the stylo-hyoid muscles. In this part of its course it lies successively on the middle constrictor of the pharj^nx and the genio-glossus muscle, and crosses a small triangular space known as 'Lesser's triangle,' the sides of which are formed by the tendons of the digastric, the base by the hypoglossal nerve, and the floor by the hyo-glossus muscle, in which situation it is usually tied. In the third part of its course it ascends tortuously, usually beneath the anterior margin of the hyo-glossus, to the under surface of the tongue, and is thence continued to the tip of that structure lying between the lingualis and the genio-glossus muscles. From the anterior edge of the hyo-glossus to its termination it is only covered by the mucous membrane of the under surface of the tongue. This part of the vessel is sometimes called the ranine artery. The lingual artery is accompanied by small vense comitantes.
(1) The hyoid branch [ramus hyoideus] (fig. 448) is a small vessel which arises from the first part of the lingual, and courses along the upper border of the hyoid bone, superficial to the hyoglossus, but beneath the insertion of the posterior belly of the digastric and the stylo-hyoid. It anastomoses with its fellow of the opposite side, and with the hyoid branch of the superior thyreoid artery, and supphes the contiguous muscles.
(2) The dorsalis linguse (fig. 448) arises from the second portion of the Ungual artery, usually under cover of the posterior edge of the h}'o-glossus muscle. It ascends to the back of the dorsum of the tongue, and, dividing into branches, supplies the mucous membrane on each side of the V formed by the vallate papillae. It also supplies the pillars of the fauces and the tonsil, where it anastomoses with the other faucial and tonsillar arteries. Instead of a single artery, as above described, there may be several small vessels running directly to the parts mentioned. The artery anastomoses in the mucous membrane by very small branches with the
vessel of the opposite side; but the anastomosis is so minute that when one Hngual artery is injected the injection merely passes across to the opposite side at the tip of the tongue; and when the tongue is divided accurately in the middle line, as in the removal of one-half of that organ, practically no haemorrhage occurs.
(3) The sublingual artery [a. sublingualis] (fig. 448) usually comes off from the lingual at the anterior margin of the hyo-glossus. It passes beneath the mylo-hyoid to the subhngual gland, which it supplies, and finally it usually anastomoses with the submental artery, a branch of the external maxillary (facial). It also supplies branches to the side of the tongue, and gives off a terminal twig, which anastomoses beneath the mucous membrane of the floor of the mouth (to which it also gives twigs) with the artery of the opposite side. The artery of the frgenum is usually derived from this vessel (fig. 448).
(4) The deep lingual [a. profunda hnguai], the termination of the hngual, courses forward beneath the mucous membrane, on the under surface of the tongue, to the tip. It lies lateral to the genio-glossus, between that muscle and the inferior lingualis, and is accompanied by the lingual vein and terminal branch of the lingual nerve. It follows a very tortuous course, so that it is not stretched when the tongue is protruded. Branches are given off from it to the contiguous muscles and mucous membrane. Near the tip of the tongue it communicates with its fellow of the opposite side, as shown by the fact that when the lingual artery of one side is injected, the injection fluid passes into the branches of the artery of the other side.
The external maxillary or facial artery [a. maxillaris externa] (fig. 449) arises immediately above the lingual from- the fore part of the external carotid, at times as a common trunk with the lingual. It courses forward and upward in a tortuous manner to the mandible, and, passing over the body of this bone at the anterior edge of the masseter muscle, winds obliquely upward and forward over the face to the medial angle of the eye, where it anastomoses, under the name of the angular artery, with the dorsal nasal branch of the ophthalmic. It is usually divided into two portions — the cervical and the facial.
The cervical portion (fig. 449) ascends tortuously from its origin from the external carotid upward and forward beneath the posterior belly of the digastric and stylo-hyoid muscles, and usualty also beneath the hypoglossal nerve, and then, making a turn, runs horizontally forward for a short way beneath the jaw, either imbedded in or lying under the submaxillary gland. It has here the mylo-hyoid and stylo-glossus beneath it. On leaving the cover of the gland it forms a loop passing first downward and then upward over the lower border of the jaw immediately in front of the masseter muscle, where it is superficial, being merely covered by the integument and platysma. Here it can be felt beating, and can be readily compressed. In the above course it lies in the posterior part of the submaxillary triangle, and, in addition to the structures already mentioned as crossing it, is covered by the skin, superficial fascia, and platysma, and by one or two submaxillary lymphatic nodes. The vein is separated from the artery by the
muscle, and the hypoglossal nerve.
The facial portion (fig. 449) of the external maxillary artery ascends tortuously forward toward the angle of the mouth, passing under the platysma (risorius), the zygomatic muscle, the zygomatic head of the quadratus labii superioris (zygomaticus minor), and the zygomatic and buccal branches of the facial nerve. It here lies upon the jaw and the buccinator muscle. Thence it courses upward by the side of the nose toward the medial angle of the eye, passing over or under the infraorbital and angular heads of the quadratus labii superioris, and under the infraorbital branches of the facial nerve. It lies on the caninus (levator anguli oris) and the infraorbital branches of the fifth nerve. The anterior facial vein takes a straighter course than the external maxillary artery, is separated from it by the zygomatic muscle, and lies lateral to it.
(1) The ascending palatine [a. palatina ascendens] (figs. 448, 449) — the first branch of the external maxillary, but often a distinct branch of the external carotid — ascends between the internal and external carotids, and then between the stylo-glossus and stylo-pharyngeus muscles, and on reaching the wall of the pharynx is continued upward between the superior constrictor and internal pterygoid muscles toward the base of the skull as high as the levator veli palatini, where it divides into two branches, a palatine and a tonsillar. One of these branches, the palatine, passes with the levator veU palatini over the curved upper margin of the superior constrictor to the soft palate, where it is distributed to the tissues constituting that structure, and anastomoses with its fellow of the opposite side and with the descending palatine branch of the internal maxillary, and the ascending pharyngeal, which vessel often to a great extent supplies the place of this artery. The other branch, the tonsillar, supplies the tonsil and the Eustachian tube, anastomosing with the tonsillar branch of the external maxillary (facial) and ascending pharyngeal arteries. The ascending palatine artery supphes the muscles between which it runs on its way to the palate.
(2) The tonsillar branch [ramus tonsillaris] (fig. 449) ascends between the stylo-glossus and internal pterygoid muscles to the level of the tonsil, where it perforates the superior constrictor muscle of the pharynx, and ends in the tonsil, anastomosing with the tonsillar branch of the ascending palatine and with the other tonsillar arteries (fig. 448). It gives branches also to the root of the tongue.
(3) The glandular branches [rami glandulares] are distributed to the submaxillary gland as the artery is passing through or beneath that structure. A small twig from one of these branches usually supplies the submaxillary (Wharton's) duct.
(4) The submental artery [a. submentahs] (fig. 449) comes off from the external maxillary as the latter vessel lies under cover of the submaxillary gland, and, passing forward on the mylo-hyoid muscle between the base of the jaw and the anterior belly of the digastricus, supphes these structures and the overlying platysma and integuments. It anastomoses with the sublingual artery. The external maxillary also supphes the adjacent muscles of the neck.
Branches of the External Maxillary Artery on the Face
From the lateral or concave side of the artery are given off branches which supply the masseter muscle and anastomose with the masseteric and buccinator branches of the internal maxillary artery, the transverse facial artery, and the infraorbital arteries.
(1) The inferior labial artery [a labiahs inferior] arises at the angle of the mouth and runs in the under Up within the substance of the orbicularis oris, close to the mucous membrane. It anastomoses with the artery of the other side. Frequently an additional branch passes from the external maxillary to the lower lip.
(2) The superior labial artery [a. labialis superior] arising from the facial a httle higher than the inferior, passes forward beneath the zygomaticus, and then, hke the inferior labial, courses tortuously along the lower margin of the upper hp between the orbicularis oris and the mucous membrane, about 1.2 cm. (i in.) from the junction of the mucous membrane and the skin. It is usually larger than the inferior labial. It anastomoses with its fellow of the opposite side, and gives off a small artery to the septum — arteria septi nasi. Compression of this vessel will sometimes control hiemorrhage from the nose.
(3) The angular artery [a. angularis] (fig. 449) is the terminal branch of the external maxillary. It supplies the nose and anastomoses at the medial angle of the eye with the dorsal nasal branch of the ophthalmic. It is accompanied by the anterior descending vein from the scalp.
It lies to the medial side of the lacrimal sac and supphes that structure and the lower part of the orbicularis oculi, beneath which a branch anastomoses with the infraorbital artery. The situation of the artery to the medial side of the lacrimal sac should be borne in mind in opening a lacrimal abscess.
THE STERNOCLEIDOMASTOID
The sternocleidomastoid artery [a. sternocleidomastoidea] arises from the posterior side of the external carotid at the point where the carotid is crossed by the digastric muscle. It is distributed to the sternocleidomastoid muscle, and is frequently represented by one of the muscular branches of the occipital artery.
The occipital artery [a. occipitalis] (fig. 450) is usually a vessel of considerable size. It comes off from the posterior part of the external carotid opposite the external maxillary (facial), or else a little higher than that vessel. It then winds
THE POSTERIOR AURICULAR ARTERY 543
upward and backward to the interval between the mastoid process of the temporal bone and transverse process of the atlas, and, after running horizontally backward in a groove on the mastoid portion of the temporal bone, again turns upward, and ends by ramifying in the scalp over the back of the skull, extending as far forward as the vertex.
In the first part of its course the occipital artery is covered by the integuments and fascia, and is more or less overlapped by the posterior belly of the digastric muscle, the parotid gland, and posterior facial (temporo-maxillary) vein. It is crossed by the hypoglossal nerve as the latter winds forward over the carotid vessels to reach the tongue. It successively crosses in front of the internal carotid artery, the hypoglossal nerve, the vagus nerve, the internal jugular vein, and tlie spinal accessory nerve.
In the second part of its course it sinks deeply beneath the digastric muscle into the interval between the mastoid process of the temporal bone and the transverse process of the atlas. It is here covered by the sterno-mastoid, splenius capitis, and longissimus capitis muscles and by the origin of the digastric; and lies, first on the rectus capitis laterahs, which separates it from the vertebral artery, then in a groove, the occipital groove, on the mastoid portion of the temporal bone, and then on the insertion of the superior oblique muscle.
In the third part of its course it enters the triangular interval formed by the diverging borders of the splenius capitis and the superior nuchal line of the occipital bone. Here it lies beneath the integuments and the aponeurosis uniting the occipital attachments of the sterno-mastoid and trapezius, and rests upon the semi-spinalis capitis (complexus) just before tlie insertion of that muscle into the occipital bone. In company with the greater occipital nerve, it perforates either this aponeurosis, or less often the posterior belly of the epicranius (occipito-frontaHs), and follows roughly, but in a tortuous course, the line of the lamboid suture, lying between the integument and the cranial aponeurosis. In the scalp it divides into several large branches, which ramify over the back of the skull and reach as far forward as the vertex. They anastomose with the corresponding branches of the opposite side, and with the posterior auricular and the superficial temporal arteries.
(1) The muscular branches [rami musculares] (fig. 450) supply the sternocleidomastoid and adjacent muscles. One of these branches may take the place of the sterno-mastoid branch of the external carotid. The hypoglossal nerve then, as a rule, loops round it instead of round the occipital.
(2) The meningeal branches [rami meningei] (fig. 450), one or more in number, are long slender vessels which leave the occipital artery as it crosses the internal jugular vein and, ascending along the vessel, pass with it through the jugular or hypoglossal foramen, and are distributed to the dura mater lining the posterior fossa of the skull.
and the mastoid cells.
(5) The descending or princeps cervicis [ramus descendens] (fig. 450), the largest of the branches of the occipital, arises from that artery just before it emerges from beneath the splenius, and, descending for a short distance between the splenius and semi-spinalis capitis (complexus), divides into a superficial and a deep branch. The superficial branch perforates the splenius, supplies branches to the trapezius, and anastomoses with the ascending branch of the transverse cervical artery. The deep branch passes downward between the semi-spinahs capitis (complexus) and colli, and anastomoses with the deep cervical branch of the costo-cervical trunk and with branches of the vertebral. The anastomoses between the above-mentioned arteries form important collateral channels after hgature of the common carotid and subclavian arteries (fig. 444).
(6) The occipital or terminal branches [rami occipitales] (fig. 450), usually two in number, named from their position medial and lateral, ramify over the scalp, and have already been described. The medial branch generally gives off a twig which enters the parietal foramen (parietal artery) and is distributed to the dura mater. The occipital artery may also give off the stylo-mastoid, the posterior auricular, or the ascending pharyngeal arteries.
posterior belly of the digastric, about the level of the tip of the styloid process. Occasionally it arises under cover of the digastric, quite close to, or as a common trunk with, or as a branch of, the occipital. It courses upward and backward in the parotid gland to the notch between the margin of the external auditory meatus and the mastoid process, where it divides into branches. In this course it rests on the styloid process, crosses the spinal accessory nerve, and is crossed by the facial nerve.
(1) The stylo-mastoid artery [a. stylomastoidea] comes off from the posterior auricular artery just before it reaches the notch between the margin of the external auditory meatus and the mastoid process, and, following the facial nerve upward, enters the stylo-mastoid foramen in the temporal bone. In the facial canal (aqueduct of Fallopius) it gives off the following named twigs: — (a) meatal, to the external auditory meatus; (6) mastoid [rami mastoidei], to the mastoid cells and tympanic antrum; (c) stapedic [ramus stapedius], which runs forward to the stapedius muscle; (d) posterior tympanic [a. tympanica posterior], which anastomoses with the anterior tympanic branch of the internal maxillary, forming with it in the foetus a vascular circle around the membrana tympani; (e) vestibular, to the vestibule and semicircular canals; and (J) terminal, a small twig which leaves the facial canal (by the hiatus) with the great superficial petrosal nerve, and anastomoses with the superior petrosal branch of the middle meningeal artery.
THE INTERNAL MAXILLARY ARTERY 545
skin. It anastomoses with the posterior branch of the superficial temporal artery. The branches to the pinna not only supply the back of that structure, but some perforate the cartilage, and others turn over its free margin to supply the lateral surface; there they anastomose with the anterior auricular branches from the temporal.
(3) The occipital branch [ramus ooeipitahs] passes upward and backward, crossing the aponeurotic insertion of the sterno-mastoid muscle. It gives a branch to the posterior belly of the epioranius (occipito-frontaHs), and anastomoses with the occipital artery.
The superficial temporal artery [a. temporalis superficialis] (fig. 445), is the smaller of the two terminal divisions of the external carotid, though apparently the direct continuation of that vessel. It arises opposite the neck of the mandible and, under cover of the parotid gland, passes upward in the interval between the condyle and the external auditory meatus to the zygoma, lying on the capsule of the temporo-mandibular joint. Thence it ascends over the posterior zygomatic root and the temporal aponeurosis for about 4 or 5 cm. (1| or 2 in.), and there divides into frontal and parietal branches. It is surrounded by a dense plexus of sympathetic nerves, and is accompanied by the auriculo-temporal nerve, which lies beneath and generally a little behind it. It is crossed by the temporal and zygomatic branches of the facial nerve, and by the auricularis anterior (attrahens aurem) muscle. As it crosses the zygoma it can be readily felt pulsating immediately in front of the ear, and in this situation can be compressed against the bone. It is here quite superficial, being merely covered by the integuments and a delicate prolongation from the cervical fascia (fig. 445) .
Branches of the Superficial Temporal Artery
The branches of the superficial temporal artery are: — (1) The parotid; (2) the transverse facial; (3) the anterior auricular; (4) the zygomatico-orbital; (5) the middle temporal; (6) the frontal; (7) the parietal.
parotid gland.
(2) The transverse facial [a. transversa faciei] is the largest branch of the temporal. It sometimes arises from the external carotid as a common trunk with the temporal. It is at first deeply seated in the substance of the parotid gland, but soon emerging from the upper part of the anterior border of the gland known, courses transversely across the masseter muscle about a finger's breadth below the zygoma. The parotid duct runs below it, and the zygomatic (infraorbital) branches of the facial nerve above it. It supphes the parotid gland, the masseter muscle, and the skin of the face, and anastomoses with the infraorbital, the buccal, and the external maxillary (facial) arteries.
auditory meatus.
(4) The zygomatico-orbital artery [a. zygomaticoorbitahs] (fig. 445), at times a branch of the deep temporal, passes forward along the upper border of the zygoma, in the fat between the superficial and deep layers of the temporal aponeurosis, and, after giving branches to the orbicularis oculi, sends one or more twigs into the orbit through foramina in the zygomatic (malar) bone to anastomose with the lacrimal and palpebral branches of the ophthalmic.
(5) The middle temporal artery [a. temporahs media] (fig. 453), arises just above the zygoma, and, perforating the temporal aponeurosis and temporal muscle, ascends on the squamous portion of the temporal bone, and anastomoses with the posterior deep temporal artery.
(6) The frontal or anterior terminal branch [ramus frontalis] ramifies tortuously in an upward and forward direction over the front part of the skull. It hes first between the skin and temporal fascia and then between the skin and epicranial aponeurosis. It supphes the anterior belly of the epicranius (occipito-frontahs) and the orbicularis ocuh muscles, and anastomoses with the supraorbital and frontal branches of the ophthalmic, and with the corresponding artery of the opposite side. The secondary branches given off from this vessel to the scalp run from before backward.
(7) The parietal or posterior terminal branch [ramus parietahs] ramifies on the side of the head between the skin and temporal fascia. Its branches anastomose, in front with the anterior terminal branch; behind, with the posterior auricular and occipital arteries; and above, across the vertex of the skull, with the corresponding artery of the opposite side.
The internal maxillary artery [a. maxillaris interna] (fig. 451) is the larger of the two terminal divisions of the external carotid. It arises opposite the neck of the mandible in the substance of the parotid gland, and, passing first between the mandible and the spheno-mandibular ligament and then between the external
and internal pterygoid muscles, sinks deeply into the pterygo-palatine (sphenomaxillary) fossa, and there breaks up into its terminal branches. It is divided into three portions: a mandibular, a pterygoid, and a pterygo-palatine.
(1) In the first part of its coixrse (the mandibular portion) the artery lies between the neck of the mandible and the spheno-mandibular ligament, taking a horizontal course forward, nearly parallel to and a httle below the auriculotemporal nerve and the external pterygoid muscle. It is here embedded in the parotid gland, and usually crosses in front of the inferior alveolar (dental) nerve.
(2) In the second part of its course (the pterygoid portion) the artery may be placed superficial or deep to the external pterygoid muscle. In the first case it passes between the two pterygoid muscles and the ramus of the jaw, and then turns upward over the lateral surface of the external pterygoid, medial to the temporal muscle to gain the two heads of the external pterygoid, between which it
sinks into the pterygo-palatine fossa. In the second case it passes medial to the external pterygoid, and is covered by that muscle till it reaches the interval between its two heads, where it then often forms a projecting loop as it turns into the pterygo-palatine fossa.
(3) In the third part of its course (the pterygo-palatine portion) the artery lies in the pterygo-palatine fossa beneath the maxillary division of the fifth nerve and in close relationship with the spheno-palatine (Meckel's) ganglion, and there breaks up into its terminal branches.
(A) From the first part : — (1) The deep auricular; (2) the anterior tympanic; (3) the middle meningeal; (4) the inferior alveolar (dental); (5) the accessory meningeal (sometimes). All these vessels pass through bony or cartilaginous canals.
(B) From the second part : — fl) The masseteric; (2) the posterior deep temporal; (3) the pterygoid; (4) the buccal; and (5) the anterior deep temporal. All these branches supply muscles.
(C) From the third part: — (1) The posterior superior alveolar (dental); (2) the infra-orbital; (3) the descending palatine; (4) the a. canalis pterygoidei or Vidian; and (5) the spheno-palatine. All these branches pass through bony canals.
Maxillary Artery
(1) The deep auricular artery [a. auricularis profunda] (fig. 451) passes upward in the substance of the parotid gland behind the capsule of the temporo-mandibular joint, and, perforating the bony or cartilaginous wall of the external auditory meatus, supplies the skin of that passage and the membrana tympani. It at times gives a branch to the joint as it passes behind the temporo-mandibular articular capsule.
Major and minor palatine arteries
(2) The anterior tympanic artery [a. tympanica anterior] is a long slender vessel, which runs upward behind the condyle of the jaw to the petro-tympanic (Glaserian) fissure, through which it passes to the interior of the tympanum. Here it supphes the fining membrane of that cavity and anastomoses with the other tympanic arteries, forming with the posterior tympanic branch of the stylo-mastoid artery a vascular circle around the membrana tympani. This circle is more distinct in the foetus than in the adult.
(3) The middle meningeal artery [a. meningea media] is the largest branch of the internal ma.xillary artery. It comes off from the vessel as it hes between the spheno-mandibular ligament and the ramus of the jaw, and under cover of the external pterygoid passes directly upward to the foramen spinosum, through which it enters the interior of the cranium. In this part of its course it is crossed by the chorda tympani nerve; and just before it enters the foramen is embraced by the two heads of origin of the auriculo-temporal nerve (fig. 451).
The trunk of the mandibular division of the fifth nerve, as it emerges from the foramen ovale, lies in front of the artery. As the artery passes upward it is surrounded b3' filaments of the sympathetic nerve, and is accompanied by two veins. On entering the skull it ramifies between the bone and dura mater, supplying both structures. It at first ascends for a short
The anterior branch passes upward, in the groove on the greater wing of the sphenoid, on to the parietal bone at its anterior and inferior angle; at this spot the groove becomes deepened and often bridged over by a thin plate of bone, being converted for 6 to 12 mm. (j to I in.) or more into a distinct canal. The situation of the artery is here indicated on the exterior of the skull by a spot 3.7 cm. (Ij in.) behind, and about 2.5 cm. (1 in.) above, the zygomatic process of the frontal bone. The anterior branch is continued along the anterior border of the parietal bone nearly as far as the superior sagittal sinus, and gives off in its course, but especially posteriorly, large branches which ramify in an upward and backward direction in grooves on the parietal bone (fig. 452).
The posterior branch passes backward over the squamous portion of the temporal bone; and thence on to the parietal bone, behind the anterior branch. This branch and its collaterals extend upward as far as the sagittal sinus, and backward as far as the transverse (lateral) sinus.
In addition to its terminal anterior, and terminal posterior branches, the middle meningeal gives off: — (a) Ganglionic branhecs to the semOunar (Gasserian) gangUon and its sheath of dura mater, (b) A superficial petrosal branch [ramus petrosus superficiahs], which enters the hiatus of the facial canal in company with the large superficial petrosal nerve and anastomoses with the terminal branch of the stylo-mastoid artery, (c) A superior tympanic artery [a. tympanica superior], which enters the canal for the tensor tympani, and supplies that muscle. (d) An orbital or lacrimal branch, which enters the orbit at the outermost part of the superior orbital (sphenoidal) fissure, or sometimes through a minute foramen, just lateral to that fissure, and anastomoses with the lacrimal branch of the ophthalmic, (e) Anastomotic or perforating branches which pierce the greater wing of the sphenoid bone, and anastomose with the deep temporal arteries.
(4) The inferior alveolar artery [a. alveolaris inferior] (fig. 451), arising from the internal maxillary as it lies between the spheno-mandibular hgament and neck of the jaw, courses downward to the mandibular foramen, which it enters in company with, and a little behind and lateral to, the inferior alveolar nerve. It then passes along the canal in the interior of the bone, giving off branches to the molar, premolar, and canine teeth. On reaching the mental foramen it divides into two branches, the incisive and the mental. The incisive continues its course in the bone, supplies branches to the incisor teeth, and anastomoses with the artery of the opposite side. The mental branch [ramus mentahs] passes through the mental foramen in company with the mental branch of the inferior alveolar (dental) nerve, and emerges on the chin under cover of the quadratus labii inferioris. It anastomoses above with the inferior labial (coronary), and below with the submental, and also with the inferior labial. Near its origin the artery gives off (a) a lingual or gustatory branch, which accompanies and supplies the lingual nerve, and ends in the mucous membrane of the mouth; and, just before it enters the mandibular (dental) foramen in the lower jaw, (6) a mylo-hyoidean branch [ramus mylohyoideus], which accompanies the nerve of that name along the groove in the lower jaw, and, after supplying the mylo-hyoid muscle, anastomoses with the subhngual and submental arteries.
(5) The accessory or small meningeal branch [ramus meningeus aocessoria] arises either from the internal maxillary a little in front of the middle meningeal, or as a branch of the latter vessel. It passes upward along the com'se of the mandibular division of the fifth nerve, and, entering the skull through the foramen ovale, is distributed to the semilunar (Gasserian) ganglion, and to the waUs of the cavernous sinus and the dura mater in the neighbourhood.
Branches op the Second Part of the Internal IMaxillary Artery
The branches of the second portion of the internal maxillary all supply muscles. They are: — (1) The masseteric; (2) the posterior deep temporal; (3) the pterygoid; (4) the buccal; and (5) the anterior deep temporal.
(1) The masseteric artery [a. masseterica] comes off from the internal maxillary as the latter is passing from between the neck of the jaw and the spheno-mandibular ligament. It passes, with the masseteric nerve tln-ough the mandibular (sigmoid) notch in the mandible and supplies the masseter muscle. Some filaments perforate the muscle and anastomose with the transverse facial and with the masseteric branches of the external maxillary (facial).
(2) The posterior deep temporal artery [a. temporalis profunda posterior] arises, as a rule, from the internal maxillary in common with the masseteric for a little be3'ond that branch. It passes upward beneath the temporal muscle in a slight groove on the anterior margin of the squamous portion of the temporal bone, supplying the temporal muscle, the pericranium and the external layer of the bone. It anastomoses with the other temporal arteries.
the internal and external pterygoid muscles.
(4) The buccal artery [a. buccinatoria] (fig. 451) courses forward and downward with the buccal nerve to the buccinator muscle, lying in close contact with the medial side and anterior margin of the tendon of the temporal muscle and coronoid process of the lower jaw. It supplies the buccinator muscle and mucous membrane of the mouth, and anastomoses with the external maxillary (facial), transverse facial, and infraorbital arteries.
(5) The anterior deep temporal artery [a. temporalis profunda anterior] ascends beneath the temporal muscle in a slight groove on the greater wing of the sphenoid bone. It supplies the muscle, pericranium, and subjacent bone, and gives off small branches which pass through minute foramina in the zygomatic (malar) bone. Some of these last branches enter the orbit and anastomose with the lacrimal artery; others emerge on the face and anastomose with the transverse facial artery.
The branches of the third part of the internal maxillary artery, like those of the first part, all pass through bony canals. They are the following: — (1) The posterior superior alveolar (dental); (2) the infraorbital; (3) the descending palatine; (4) the artery of the pterygoid canal (Vidian); and (5) the sphenopalatine.
(1) The posterior superior alveolar (dental) artery [a. alveolaris superior posterior] arises from the internal maxiUary as the latter is passing into tlie pterygo-palatine (spheno-maxillary) fossa, and descends in a tortuous manner in a gi'oove on the back of the body of the maxilla. It gives off branches to the maxillary sinus, to the molar and premolar teeth, the gums, and to the buccinator muscle.
(2) The infraorbital artery [a. infraorbitalis] arises from the internal maxillary, generally as a common trunk with the posterior alveolar (dental). It passes forward and a little upward through the pterygo-palatine (spheno-maxillary) fossa; then forward in company with the infraorbital branch of the fifth nerve, first along the groove, and then tlirough the canal in the orbital plate of the maxilla; and finally, emerging on the face at the infraorbital foramen, under cover of the quadratus labii superioris, is distributed to the structures forming the upper Up, the lower eyeUd, the lacrimal sac, and the side of the nose. It anastomoses with the superior labial (coronary) and angular branches of the external maxillary (facial), with the nasal and lacrimal branches of the ophthalmic, and with the transverse facial. It gives off small branches supplying the fat of the orbit and the inferior rectus and inferior oblique muscles. The anterior superior alveolar branch [a. alveolaris superior anterior] passes downward through a groove in the anterior wall of the maxilla, together with the anterior alveolar branch of the infraorbital nerve, and supplies branches to the incisor and canine teeth and the mucous membrane of the maxillary sinus. It has also nasal branches which pass through the foramina in the nasal process of the maxiUa.
(3) The descending palatine artery [a. palatina descendens] descends in the pterygopalatine canal with the anterior palatine branch of the spheno-palatine ganglion. On emerging on the palate at the greater (posterior) palatine foramen, it divides into the following branches; — (a) The major palatine artery [a. palatina major], which courses forward in the muco-periosteum at the junction of the hard palate with the alveolar process as far as the incisive (anterior palatine) foramen, where it anastomoses with the spheno-palatine artery; and (b) minor palatine arteries [aa. palatina; minores], which pass backward and downward into the soft palate, contributing to the supply of that structure, and anastomosing with the ascending palatine artery. After the operation for cleft palate, serious heemorrhage occasionally occurs from the descending palatine artery. The foramen is situated a little behind, and medial to, the last molar tooth, and almost immediately in front of the hamular process (fig. 452).
(4) The arteria canalis pterygoidei or Vidian artery is a long slender branch which passes backward through the pterygoid (Vidian) canal in company with the nerve of tlie same name into the cartilage of the lacerated foramen. It gives off branches which supply the roof of the pharynx, and anastomose with the ascending pharyngeal and spheno-palatine arteries; also a branch which is distributed to the Eustachian tube; and one which enters the tympanum, and anatomoses with the other tympanic arteries.
(.5) The spheno-palatine [a. sphenopalatina], the terminal branch of the internal maxillary, passes with the naso-palatine branch of the spheno-palatine ganglion from the pterygo-palatine (spheno-maxillary) fossa into the nose through the spheno-palatine foramen. Crossing the roof of the nose in the muco-periosteum, it passes on to the septum, and then runs forward and downward in a groove on the vomer toward the incisive (anterior palatine) foramen, where it anastomoses with the anterior palatine artery, which enters the nose through the lateral compartment of that foramen (the canal of Stenson). In this course it gives off branches to the roof and contiguous portions of the pharynx, and to the sphenoidal cells. It has also posterior lateral nasal branches [aa. nasales post, laterales], which ramify over the nasal conchse (turbinate bones) and lateral walls of the nose, and give twigs to the ethmoidal and frontal sinuses and the Uning membrane of the maxillary sinus; and posterior septal branches [aa. nasales post, septi], which run upward and forward, giving small twigs to the mucous membrane covering the upper part of the septum, and which pass through the cribriform plate of the ethmoid, and anastomose with the ethmoidal arteries (perforating or meningeal branches).
The internal carotid artery [a. carotis interna] (figs. 453 and 454) arises with the external carotid at the bifurcation of the common carotid, opposite the upper border of the thyreoid cartilage, on a level with the fourth cervical vertebra. It is at first placed a little lateral to the external carotid, but as it ascends in the neck the external carotid becomes more superficial and in front of the internal. The internal carotid passes up the neck, in front of the transverse processes of the upper cervical vertebrae, lying upon the longus capitis (rectus capitis ant. major), to the carotid foramen, thence through the carotid canal in the petrous portion of the temporal bone, making at first a forward and medial turn and then a second turn upward, and enters the cranium through the foramen lacerum. It makes a sigmoid curve on the side of the body of the sphenoid bone, and terminates, after perforating the dura mater, by dividing opposite the anterior clinoid processes
In its course up the neck it often forms one or more curves, especially in old people. Between the internal and the external carotids, at their angle of divergence, is situated the carotid body or gland [glomus caroticum].
The internal carotid is the continuation upward of the primitive dorsal aorta, and supplies the greater part of the brain, the contents of the orbit, and parts of the internal ear, forehead, and nose. It is divided into three portions: — (1) a cervical; (2) a petrosal; and (3) an intracranial.
deep fascia, and the overlapping edge of the sterno-mastoid muscle. Higher up, as it sinksHDeneath the parotid gland, it becomes deeply placed, and is crossed by the posterior belly of the digastric and stylo-hyoid muscles, the hypoglossal nerve, and the occipital and posterior auricular arteries; whilst still higher it is separated from the external carotid artery, which here gets
Behind, it hes upon the longus capitis (rectus capitis anticus major), which separates it from the transverse processes of the three upper cervical vertebrae, on the superior cervical ganglion of the sympathetic nerve, and on the vagus nerve. Near the base of the skull, the hypofilossal, vasus, glosso-pharyngeal, and spinal accessory nerves cross obhquely behind it, separating it here from the internal jugular vein, which, as the artery is about to enter the carotid canal, also forms one of its posterior relations.
On its lateral side are the internal jugular vein and vagus nerve.
On its medial side it is in relation with the pharynx, the superior constrictor muscle separating it from the tonsil. The ascending pharyngeal and ascending palatine arteries, and at the base of the skull the Eustachian tube and levator palati muscles, are also medial to it.
2. Thf Petrosal Portion
The petrosal portion (fig. 454) is situated in the carotid canal in the petrous portion of the temporal bone. It is here separated from the walls of the canal by a prolongation downward of the dura mater. In this part of its course it first ascends in front of the tympanum and cochlea of the internal ear; it then turns forward and medially, lying a little medial to and behind the Eustachian tube, and enters the cranial cavity by turning upward through the fora-
men lacerum, lying upon the Ungula of the sphenoid bone. In this part of its course it is accompanied by the ascending branches from the superior cervical ganghon of the sympathetic. These form a plexus about the artery, but are situated chiefly on its lateral side. It is also surrounded by a number of small veins, which receive tributaries from the tympanum and open into the cavernous sinus and internal jugular vein.
3. The Intracranial Portion
On entering the cranium through the foramen lacerum, the internal carotid first ascends to reach the lateral part of the body of the sphenoid medial to the hngula. It then follows the carotid sulcus forward and slightly downward along the medial waU of the cavernous smus (fig. 454). Here it has the sixth nerve immediately lateral to it, and is covered by the hning membrane of the sinus. Again turning upward, it pierces the dura mater on the medial side of the anterior clinoid process, and, passes between the second and third nerves to the anterior perforated substance. At the medial end of the lateral (Sylvian) fissure it pierces the arachnoid and divides into its two terminal branches, the anterior and middle cerebral. As it hes in the
The cervical portion gives off no branch. The petrosal portion gives off the caroticotympanic. The branches of the intracranial portion are : — (2) ophthalmic ; (3) posterior communicating; (4) chorioid; (5) anterior cerebral; (6) middle erebral.
As the internal carotid artery lies on the medial side of the cavernois sinus, it also gives off the following small branches — branches to the walls of the cavernous inus; to the pituitary body; to the semilunar (Gasserian) ganglion; to the dura mater. These anastomose with anterior branches of the middle meningeal.
1. THE CAROTICOTYMPANIC ARTERY
The caroticotympanic enters the tympanum through a small foramen in the posterior wall of the carotid canal, and contributes its quota to the blood-supply of that cavity. It anastomoses with the tympanic branches of the stylo-mastoid, internal maxillary, and middle meningeal arteries.
2. THE OPHTHALMIC ARTERY
The ophthalmic artery (fig. 455) comes off from the internal carotid immediately below the anterior clinoid process just as the latter vessel is passing through the dura matter. Entering the orbit through the optic foramen below and lateral to theo ptic nerve, it at once perforates the sheath of dura mater which is prolonged through the optic foramen on both artery and nerve. It then runs in a gentle curve with a lateral convexity below the optic nerve and lateral rectus, being here crossed by the naso-ciliary (nasal) nerve. Turning forward and upward, it passes over the optic nerve, to its medial side. Thence it runs obHquely beneath the superior rectus in front of the naso-ciliary (nasal) nerve under the lower border of the superior oblique, but above the medial rectus, and continues its course under the pulley for the superior oblique and reflected tendon of that muscle to the medial palpebral region, where it divides into the frontal and nasal branches.
The branches of the ophthalmic artery are: — (1) the lacrimal; (2) the supraorbital; (3) the central artery of the retina; (4) the muscular; (5) the ciliary; (6) the posterior ethmoidal; (7) the anterior ethmoidal; (8) the medial palpebral; (9) the frontal; and (10) the dorsal nasal.
(1) The lacrimal artery [a. laorimalis], is usually the first and often the largest branch 9f the ophthalmic. It arises between the superior and lateral rectus on the lateral side of the optic nerve from the ophthalmic, soon after that vessel has entered the orbit. At times it is given off from the ophthalmic outside the orbit, and then usually passes into that cavity through the superior orbital (sphenoidal) fissure. It runs forward along the lateral waO of the orbit with the lacrimal nerve, above the upper border of the lateral rectus, to the lacrimal gland, which it supplies. In this course it furnishes the following branches: — (a) Recurrent, one or more branches which pass backward through the superior orbital (sphenoidal) fissure, and anastomose with the lacrimal branch of the middle meningeal artery. The anastomosis is sometimes of large size, and then takes the chief share in the formation of the lacrimal artery, (b) Muscular branches, distributed chiefly to the lateral rectus, (c) Zygomatic branches — small twigs, which pass through the zygomatico-orbital (malar) canals, and anastomose with the orbital branch of the middle temporal, and with the transverse facial on the cheek, (d) Lateral palpebral arteries [aa. palpebrales laterales] which are distributed to the upper- and lower eyelids and to the conjunctiva, (e) Ciliary. See Ciliary Arteries, page 553.
(2) The supraorbital artery [a. supraorbitaHs] usually arises from the ophthalmic as the latter vessel is about to cross over the optic nerve. Passing upward to the medial side of the superior rectus and levator palpebrse, it runs along the upper surface of the latter muscle with the frontal nerve in the orbital fat, but beneath the periosteum, to the supraorbital notch. On emerging on the forehead beneath the orbicularis ocuU, it divides into a superficial and deep branch, the former ramifies between the skin and epicranius (occipito-frontahs), the latter
between the epicranius and the pericranium. Both branches anastomose with the anterior branches of the superficial temporal, the angular branch of the external maxillary (facial), and the transverse facial artery. The branches of the supraorbital are: — (o) periosteal, to the periosteum of the roof of the orbit; (6) muscular, to the levator palpebra; and superior rectus;
(3) The arteria centralis retinae, a small but constant branch, comes off from the ophthalmic close to the optic foramen, and, perforating the optic nerve about 6 mm. (\ in.) behind the globe, runs forward in (the substance of the nerve) to the eyeball, supplying the retina. Its further description is given in the section on the Eye.
(4) The muscular branches [rami musculares] are very variable in their origin and distribution. They may be roughly divided into superior and inferior sets. The superior or smaller set supply the superior oblique, the levator palpebra3, and superior rectus. The inferior pass forward, between the optic nerve and the inferior rectus, supplying that muscle, the medial rectus, and the inferior oblique. From the muscular branches are given off the anterior ciliary arteries. (See Ciliary Arteries.)
(5) The ciliary arteries are divided into three sets: — The short posterior, the long posterior, and the anterior, (i) The short posterior [aa. oiliares posteriores breves], five or six in number, come off chiefly from the ophthalmic as it is crossing the optic nerve. They run forward about
Internal carotid artery
the nerve, dividing into twelve or fifteen smaU vessels, which perforate the sclerotic around the entrance of the optic nerve, and are distributed to the chorioid coat, (ii) The long posterior ciUary arteries [aa. ciliares posteriores longte], usually two, sometimes three, in number, come off from the ophthalmic on either side of the optic nerve, and run forward with the short ciliary to the sclerotic. On piercing the sclerotic, they course forward, one on either side of the eyeball between the sclerotic and the chorioid to the ciliary processes and iris. Their further distribution is given under the anatomy of the Eye. (iii) The anterior ciliary arteries [aa. ciliares anteriores] are derived from the muscular branches and from the lacrimal. They run to the globe along the tendons of the recti, forming a zone of radiating vessels beneath the conjunctiva. Some of them, the episcleral arteries [aa. episclerales] ; perforate the sclerotic about 6 mm. (-f in.) behind the cornea, and supply the iris and ciUary processes. It is these vessels that are enlarged and congested in iritis, forming the circumcorneal zone of redness so characteristic of that disease. They then differ from the tortuous vessels of the conjunctiva in that they are straight and parallel. The remainder constitute the anterior conjunctival arteries [aa. oonjunctivales anteriores].
(6) The posterior ethmoidal artery [a. ethmoidalis posterior] (fig. 455) runs medially between the superior oblique and medial rectus, and, leaving the orbit by the posterior ethmoidal canal, together with the posterior ethmoidal branch of the naso-ciliary (nasal) nerve, enters the posterior ethmoidal cells, whence it passes through a transverse slit-hke aperture between the sphenoid bone and cribriform plate of the ethmoid bone into the cranium. It gives off (a) ethmoidal branches to the posterior ethmoidal cells; (6) meningeal branches to the dura mater lining the cribriform plate; and (c) nasal branches, which pass through the cribriform plate to
(7) The anterior ethmoidal artery [a. ethmoidahs anterior] (fig. 452), a larger branch than the posterior ethmoidal, arises in front of the latter, passes medially between the superior obhque and medial rectus, and, leaving the orbit through the anterior ethmoidal canal, in company with the anterior ethmoidal nerve, enters the cranial cavity. After running a short distance beneath the dura mater on the cribriform plate of the ethmoidal bone, it passes into the nose through the horizontal slit-hke aperture by the side of the crista gaUi. Its terminal branch passes along the groove on the under surface of the nasal bone, and emerges on the nose between the bone and lateral cartilage, terminating in the skin of that organ. It gives off the following branches in its course: — (i) Ethmoidal, to the anterior ethmoidal cells; (ii) anterior meningeal artery, [a. meningea anterior] to the dura mater of the anterior fossa; (iii) nasal, to the middle meatus and anterior part of the nose; (iv) frontal, to the frontal sinuses; (v) cutaneous, or terminal, to the skin of the nose.
(8) The medial palpebral arteries [aa. palpebrales mediales] arise either separately or by a common trunk from the ophthalmic artery opposite the pulley for the superior obhque, just as the latter vessel is about to divide into its terminal branches. They pass, one above and one below, the medial palpebral hgament and then skirt along the upper and lower eyelids respectively, near the free margin between the palpebral tarsi and the orbicularis muscle, and form a superior and an inferior tarsal arch [arcus tarsus superior et inferior] by anastomosing with the lateral palpebral branches of the lacrimal. The upper also anastomoses with the supraorbital artery and orbital branch of the temporal artery; the lower with the infraorbital, the angular branch of the external maxillary (facial), and the transverse facial arteries. A branch from the lower palpebral passes with the ductus nasolacrimalis as far as the inferior meatus. Small twigs, the posterior conjunctival arteries [aa. conjunctivales posteriores], are also given to the caruncula lacrimahs and conjunctiva.
(10) The dorsal nasal [a. dorsahs nasi], the lower of the terminal branches of the ophthalmic, leaves the orbit at the medial angle by perforating the tarsus above the medial palpebral ligament. It then descends along the dorsum of the nose, beneath the integuments, and anastomoses with the angular and lateral nasal branches of the external maxillary (facial). It gives off a lacrimal branch as it crosses the lacrimal sac, and a transverse nasal branch as it crosses the root of the nose; the latter vessel anastomoses with its fellow of the opposite side.
The posterior communicating artery [a. communicans posterior] (fig. 456) is given off from the internal carotid just before the division of that vessel into the anterior and middle cerebral arteries; occasionally it arises from the middle cerebral itself.
It is as a rule a slender vessel which runs backward over the optic tract and pedunculus cerebri along the side of the hippocampal gyrus to join the posterior cerebral. At times, however, it is of considerable size, and contributes chiefly to form the posterior cerebral, the portion of the latter vessel between the basilar and posterior communicating being then as a rule reduced to a mere rudiment. It gives off the following branches: — (a) the hippocampal, to the gyrus of that name; and (6) the middle thalamic, to the optic thalamus.
It passes backward on the optic tract and the pedunculus cerebri, at first lying parallel and lateral to the posterior communicating artery. It then dips under the edge of the uncinate gyrus and, entering the chorioid fissure at the lower end of the inferior cornu of the lateral ventricle, ends in the chorioid plexus and supplies the hippocampus and fimbria.
5. THE ANTERIOR CEREBRAL ARTERY
The anterior cerebral artery [a. cerebri anterior] (figs. 456, 459), one of the terminal branches into which the internal carotid divides in the lateral fissure (fissure of Sylvius), supplies a part of the cortex of the frontal and parietal lobes of the brain and a small part of the basal ganglia. It passes at first anteriorly and medially across the anterior perforated substance between the olfactory and optic nerves to the longitudinal fissure where it approaches its fellow of the opposite side
CIRCULUS ARTERIOSUS
and communicates with it by a short transverse trunk, about five mm. long, known as the anterior communicating artery [a. communicans anterior] (fig. 456). Onward from this point it runs side by side with its fellow in the longitudinal fissure round the genu of the corpus callosum; then, turning backward, it continues along the upper surface of that commissure, and, after giving off large branches to the frontal and parietal lobules, anastomoses with the posterior cerebral artery.
The middle cerebral artery [a. cerebri media] (figs. 456, 460), the larger of the terminal divisions of the internal carotid, supplies the basal ganglia and a part of the cortex of the frontal and parietal lobes. It passes obliquely upward and lateralward into the lateral (Sylvian) fissure, and opposite the insula divides into cortical branches.
FiG. 456. — -The Arteries of the Brain. (The cerebellum has been out away on the left side to show the posterior part of the cerebrum. From a preparation in the Museum of St. Bartholomew's Hospital.)
able anastomosis at the base of the brain known as the circle of Willis [circulus arteriosus (WilHsi)]. This so-called circle, which has really the form of a heptagon, is formed, in front, by the anterior communicating artery uniting the anterior cerebral arteries of opposite sides; laterally, by the internal carotids and the posterior communicating arteries stretching between these and the posterior cerebrals; behind, by the two posterior cerebrals diverging from the bifurcation of the basilar artery (fig. 456).
This free anastomosis between the two internal carotid and the two vertebral arteries serves to ecjuaUse the flow of blood to the various portions of the brain; and, should one or more of the arteries entering into the formation of the circle be temporarily or permanently obstructed, it ensures a flow of blood to the otherwise deprived part through some of the collateral arteries. Thus, if one carotid or one vertebral is obstructed, the parts suppHed by that vessel receive their blood through the circle from the remaining pervious vessels. Indeed, one vertebral artery alone has been found equal to the task of carrying sufBcient blood for the supply of the
brain after ligature of both the carotids and the other vertebral artery. Further, the circle of Willis is the only medium of communication between the ganglionic or central and the peripheral or cortical branches of the cerebral arteries, and between the various ganglionic branches themselves. The ganglionic and the cortical branches form separate and distinct systems, and do not anastomose with each other; and the ganglionic, moreover, are so-called end-vessels, and do not anastomose with the neighbouring ganglionic branches. The three cerebral arteries, anterior, middle, and posterior may be regarded as branches of the circle of Willis. (For details concerning the distribution of the cerebral arteries see p. 562.)
THE SUBCLAVIAN ARTERY
The subclavian artery on the right side [a. subclavia dextra] arises at the bifurcation of the innominate opposite the upper limit of the right sterno-clavicular articulation. On the left side it arises from the arch of the aorta, and, as far as the medial border of the scalenus anterior, is situated deeply in the chest. The first portion of the left subclavian artery is described separately.
Beyond the medial border of the scalenus anterior the artery has the same relations on both sides. It courses from this point beneath the clavicle in a slight curve across the root of the neck to the lateral border of the first rib, there to end in the axillary artery. Thus the course of the artery in the neck will be indicated by a line drawn from the sterno-clavicular joint in a curve with its convexity upward to the middle of the clavicle. The height to which the artery rises in the neck varies. It is perhaps most commonly about 1.2 cm. (| in.) above the clavicle. If the cm-ved line above mentioned is drawn to represent part of the circumference of a circle having its center at a point on the lower margin of the clavicle 3.7 cm. d^ in.) from the sternal end of that bone, the line of the artery will be sufficiently well indicated for all practical purposes. In its course the artery arches over the dome of the pleura and gains the groove on the upper surface of the first rib by passing between the scalenus anterior and medius muscles. The artery is accompanied by the subclavian vein, the latter vessel lying in front of the scalenus anterior, anterior to the artery, and on a slightly lower plane.
The left subclavian artery [a. subclavia sinistra] (fig. 457) arises from the left end of the arch of the aorta. The first part of the left subclavian is consequently longer than the first part of the right, which arises at the bifurcation of the innominate artery. The artery at its origin is situated deeply in the thorax, and as it arises from the aorta is on a plane posterior to and a little to the left of the thoracic portion of the left common carotid. It first ascends almost vertically out of the chest, and at the root of the neck curves laterally over the apex of the left plem-a and lung to the interval between the anterior and middle scalene muscles. Beyond the medial border of the scalenus anterior — that is, in the second and third portions of its course — its relations are similar to those of the right subclavian artery.
Relations. — In front it is covered by the left pleura and lung, whilst more superficial are the sterno-thyreoid, sterno-hyoid, and sterno-mastoid muscles. It is crossed a Uttle above its origin by the left innominate vein, and higher in the neck near the scalenus anterior by the internal jugular, vertebral, and subclavian veins. The phrenic nerve crosses the artery immediately medial to the scalenus anterior, and then descends parallel to it, but on an anterior plane, to cross the arch of the aorta. The vagus nerve descends parallel to the artery between it and the left common carotid, coming into contact with its anterior surface just before crossing the arch of the aorta. The left cervical cardiac nerves of the sympathetic also descend in front of it on their way to the cardiac plexus. The left ansa subclavia also loops in front of the subclavian artery. The left common carotid is situated anteriorly and to its right. The thoracic duct arches over the artery just medial to the scalenus anterior, to empty its contents into the confluence of the internal jugular and subclavian veins (fig. 442).
Behind and somewhat medial to it are the oesophagus, thoracic duct, inferior cervical ganglion of the sympathetic, longus coUi muscle, and vertebral column. To some extent it is overlapped posteriorly by the left pleura and lung.
clavicular joint, upward and laterally in a gentle curve over the apex of the right lung and pleura to the medial border of the scalenus anterior. It measures about 3 cm, {\\ in.). In this course it ascends in the neck a variable distance above the clavicle, but is so deeply placed, so surrounded by important structures, and gives
tion of a ligature.
Relations. — In front it is covered by the integuments, the superficial fascia, the platysma, the anterior layer of the deep fascia, the clavicular origin of the sterno-mastoid, the sterno-hyoid and sterno-thyreoid muscles, and the deep cervical fascia. It is crossed by the commencement of the innominate, by the internal jugular, and by the vertebral veins; and, in a medio-lateral direction, by the vagus and phrenic nerves, and the superior cardiac branches of the sympathetic nerve. A loop of the sympathetic nerve itself also crosses the artery, and forms with the trunk of the S3'mpathetic a ring around the vessel known as the ansa subclavia (annulus of Vieussens).
Behind, but separated from the artery by a cellular interval, are the longus coUi muscle, the transverse process of the seventh cervical or first thoracic vertebra, the main chain of the sympathetic nerve, the inferior cardiac nerves, the recurrent laryngeal nerve, and the apex of the right lung and pleura.
Below, it is in contact with the pleura and lung and the loop of the recurrent laryngeal nerve, which winds round the artery from the vagus and ascends behind it to the larynx. The subclavian vein is below the artery and on an anterior plane.
Branches. — The vertebral, internal mammary, superficial cervical, and thyreocervical trunk (thyreoid axis) arise from this part of the vessel on the right side. (See p. 559.) Not uncommonly a small aberrant artery also takes origin from this portion of the artery and descends to the left behind the oesophagus to join a branch of the aorta opposite the third or fourth thoracic vertebra. This vessel is probably the remains of the right dorsal aorta.
THE SECOND PORTION OF THE SUBCLAVIAN ARTERY
The second portion of the subclavian artery lies behind the scalenus anterior muscle. It measures about 2 cm. ff in.) in length and here reaches highest in the neck. The subclavian vein is separated from the artery by the scalenus anterior, and lies on a lower and anterior plane (fig. 463) .
Relations. — In front it is covered by the skin, superficial fascia, platysma, anterior layer of deep fascia, the clavicular origin of the sterno-mastoid, posterior layer of deep fascia, and by the scalenus anterior. The phrenic nerve — which, in consequence of its oblique course medially downward, crosses a portion of both the first and second part of the subclavian — is separated from the second portion by the scalenus anterior muscle, as is also the subclavian vein which courses on a somewhat lower plane.
Below are the pleura and lung.
One branch only — the costo-cervical trunk (superior intercostal) — is, as a rule, given off from this portion of the subclavian; occasionally the transverse cervical or the descending branch of the transverse cervical (posterior scapular artery) arises from it.
The third portion of the subclavian artery extends from the lateral margin of the scalenus anterior muscle to the lateral border of the first rib. It is more superficial than either the first or second portions; it is in relation with less important structures, and as a rule gives off no branch, and for these reasons is the part selected when practicable for the application of a ligature. It is the longest of the three portions of the subclavian artery, and lies in a triangle — the subclavian triangle — bounded by the sterno-mastoid, the omo-hyoid, and the clavicle (fig. 445).
Relations. — In front it is covered by skin, superficial fascia, platysma, supra-clavicular nerves (descending superficial branches) of the cervical plexus; the anterior layer of deep fascia which descends from the omo-hyoid to the clavicle; and the posterior layer of deep fascia which descends from the omo-hyoid to the fu'st rib and passes over the scalenus anterior and phrenic nerve. Between the two layers of fascia is a variable amount of cellular tissue and fat, and running in this is the transverse scapular (supra-scapular) artery. The subclavian is crossed by this artery unless the arm is drawn well downward. Close to the lateral margin of the sterno-mastoid, the external jugular vein pierces the fascia, and crosses the subclavian artery to open into the subclavian vein. As this vein hes between the two layers of fascia, it receives on its lateral side the transverse scapular (supra-scapular), transverse cervical, and other veins of the neck, which together form a plexus of large veins in front of the arterj'. The nerve to the subclavius, and, when present, the accessory branch from this nerve to the phrenic, also
Above is the brachial plexus of nerves and the posterior beUy of the omo-hyoid muscle. The trunk formed by the fifth and sixth cervical nerves is also above the artery, but on a somewhat anterior plane. It is close to the vessel, and has been mistaken for the artery in the appUcation of a Kgature.
As a rule there is no branch given off from the third portion of the subclavian. At times, however, the transverse cervical or the descending branch of the transverse cervical (posterior scapular artery) may arise from the third portion of the subclavian instead of from the thyreo-cervical trunk (thyreoid axis) and from the transverse cervical respectively, as here described.
There is considerable variation in the branches of the subclavian artery and Bean (Am. Jour. Anat., Vol. 4, p. 303) has shown that the branches are arranged in a different way on the two sides of the body. The usual form on the right side is for the vertebral, internal mammary, the superficial cervical and the common trunk of the inferior thjTeoid and transverse scapular arteries to arise from the first part of the subclavian. In this case the ascending cervical is a branch of the inferior thyreoid, while the transverse cervical and costo-cervical arise from the second portion. There are no branches from the third portion. On the left side the usual form is for the vertebral and internal mammary, and thyreo-cervical trunk, to arise from the first part. The thyreo-cervical trunk divides into inferior thyreoid, transverse scapular, and transverse cervical arteries; the superficial cervical is absent, and the costo-cervical trunk arises from the first part.
There are three more types of origin of the branches; in one, the vertebral, internal mammary, costo-cervical, and inferior thyreoid come from the first part, while the transverse cervical arises from the second part, and the transverse scapular comes either from the third part or the axillary artery; in the second, the inferior thyreoid, transverse scapular and transverse cervical arise in a common stem from the first part; while in the third, which is the rarest form, the inferior thyreoid and superficial cervical arteries come by a common trunk from the first part, while the transverse scapular artery arises from the internal mammary.
The vertebral artery [a. vertebralis] (fig. 458) the first, largest, and most constant branch, arises from the upper and posterior part of the first portion of the subclavian, on the right side, about 2 cm. (f in.) from the origin of the latter vessel from the innominate, on the left side, from the most prominent part of the arch of the subclavian, close to the medial edge of the scalenus anterior muscle. It first ascends vertically to the foramen transversarium of the sixth cervical vertebra, and, having passed through that foramen and those of the next succeeding cervical vertebrae as high as the epistropheus (axis), it tmns laterally and then ascends to reach the foramen in the transverse process of the atlas; after passing through that foramen it turns backward behind the articular process, lying in the groove on the posterior arch of the atlas. It next pierces the posterior occipito-atlantoid membrane and the dura mater, and enters the cranium through the foramen magnum. Here it passes upward, at first lying by the side of the medulla, then in front of that structure, and terminates at the lower portion of the pons by anastomosing with the vertebral of the opposite side to form the basilar.
The vertebral artery may be divided for purposes of description into four parts: the first, or cervical, extending from its origin to the transverse process of the sixth cervical vertebra; the second, or vertebral, situated in the foramina transversaria; the third, or occipital, contained in the suboccipital triangle; and the fourth, or intracranial, within the cranium.
The first or cervical portion. — The artery here lies between the scalenus anterior and longus colli muscles. In front it is covered by the vertebral and internal jugular veins, and is crossed by the inferior thyreoid artery, and on the left side, in addition, by the thoracic duct, which runs over it medio-laterally. Behind, the artery hes on the transverse process of the seventh cervical vertebra and the sympathetic nerve. To its medial side is the longus coUi. To its lateral
The second or vertebral portion. — As the artery passes through the foramina transversaria, it is surriunded by a plexus of veins and by branches of the sympathetic nerve. The cervical nerves lie behind it. Between the transverse processes it is in contact with the intertransverse muscles.
The third or occipital portion. — The artery here hes in the suboccipital triangle, bounded by the superior oblique, inferior oblique, and rectus capitis posterior major muscles. As it winds round the groove on the atlas, it has the rectus capitis laterahs, the articular process, and the posterior ocoipito-atlantoid membrane in front of it; the superior oblique, the rectus capitis posterior major, and the semispinalis capitis (complexus) behind it. Separating it from the arch of the atlas, is the first cervical or suboccipital nerve.
The fourth or intracranial portion extends from the aperture in the dura mater to the lower border of the pons, where it pierces the arachnoid and unites with its fellow to form the basilar artery. It here winds round from the side to the front of the medulla, lying in the
The internal jugular and vertebral veins are hooked aside to expose the artery.
In this course it passes beneath the first process of the hgamentum denticulatum, and between the hypoglossal nerve in front, and the anterior roots of the suboccipital nerve behind.
The first part of the vertebral artery gives no branches. The second and third parts give off muscular branches to the semispinalis and posterior recti and oblique muscles. The second part also gives off five or six, (1) Spinal branches. The fourth part gives off the following: (2) Posterior meningeal; (3) posterior spinal; (4) anterior spinal; and (5) posterior inferior cerebellar.
(1) The spinal branches [rami spinales] run through the intervertebral foramina into the vertebral canal, and there divide into two branches: one of which ramifies on the ba,cks of the bodies of the cervical vertebra;; while the other runs along the spinal nerves, supphes the cord and its membranes, and anastomoses with the arteries above and below.
(2) The meningeal [ramus meningeus] is a small branch given off as the vertebral artery pierces the dura mater to enter the cranium. It supplies the bone and dura mater of the posterior fossa of the skull, and anastomoses with the posterior meningeal branches derived from the occipital and ascending pharyngeal arteries. It gives branches to the falx cerebelli.
THE BASILAR ARTERY 561
(3) The posterior spinal artery [a. spinalis posterior] runs downward obliquely along the side of the medulla to the back of the cord, down which it passes behind the roots of the spinal nerves, being reinforced by spinal branches accompanying these nerves, in the neck, the thoracic, and in the lumbar region. It can be traced as low as the end of the spinal cord.
(4) The anterior spinal artery [a. spinalis anterior] comes off from the vertebral a little below its termination in the basilar artery. Descending with a medial slant in front of the medulla, it unites on a level with the foramen magnum with its fellow of the opposite side. The single vessel thus formed runs downward in front of the spinal cord beneath the pia mater as far as the termination of the cord, being reinforced by the spinal branches on the way down. The spinal arteiies are described in detail with the anatomy of the spinal cord.
(5) The posterior inferior cerebellar [a. cerebeUi inferior posterior] (fig. 456) — the largest branch of the vertebral — arises from that vessel just before it joins its fellow to form the basilar artery. At times it may come off from the basilar itself. It runs, at first laterally across the restiform body between the origin of the vagus and hypoglossal nerves, and, descending toward the vallecula, there divides into two branches, medial and lateral, (a) The medial branch runs backward between the vermis and the lateral hemisphere of the cerebellum. It supplies the vermis, and anastomoses with the artery of the opposite side, and with the superior vermian of the superior cerebellar. (6) The lateral branch runs laterally and, ramifying over the under surface of the cerebellar hemisphere, supplies its cortex and anastomoses along its lateral margin with the superior cerebellar arteries.
The basilar artery [a. basilaris] is formed by the confluence of the right and left vertebral arteries, which meet at an acute angle at the lower border of the pons. It runs forward and upward in a slight groove in the middle line of the pons, and divides at the upper border of that structure at the level of the tentorial notch into the two posterior cerebral arteries, which take part in the formation of the circle of Willis (fig. 456) .
(1) The pontine branches [rami ad pontem] are numerous small vessels which come off at right angles on either side of the basilar artery, and, passing laterally over the pons, supply that structure and adjacent parts of the brain.
(2) The internal auditory artery [a. auditiva interna], a long slender vessel, accompanies the auditory nerve into the internal auditory meatus (fig 514). It here lies between the facial and auditory nerves, and at the bottom of the meatus passes into the internal ear, and anastomoses with the other auditory arteries. (See Internal Ear.)
(3) The anterior inferior cerebellar [a. cerebelU inferior anterior] arises from the basilar soon after its origin, passes laterally and backward across the pons, and then over the brachium pontis to the front part of the under surface of the cerebellum. It anastomoses with the posterior inferior cerebellar artery (fig. 456).
(4) The superior cerebellar [a. cerebelli superior] comes off from the basilar immediately behind its bifurcation into the posterior cerebral arteries. It courses laterally and backward over the pons, in a curve roughly corresponding to that of the posterior cerebral artery, from which it is separated by the third cranial nerve; but, soon sinking into the groove between the pons and the pedunculus cerebri, it curves round the latter onto the upper surface of the cerebellum, lying nearly parallel to the fourth nerve. Here it divides into two branches medial and lateral, (o) The medial branch courses backward along the superior vermis, anastomosing with its fellow of the opposite side, and, at the posterior notch of the cerebellum, with the inferior vermian branch of the posterior inferior cerebellar artery. (6) The lateral runs to the circumference of the cerebellum, anastomosing with the lateral branch of the inferior posterior cerebellar artery.
body, and the chorioid plexus.
(5). The posterior cerebral arteries [aa. cerebri posteriores] are the two terminal branches into which the basilar bifurcates at the upper border of the pons, immediately behind the posterior perforated substance. Each artery runs at fii'st laterally and a little forward across the pedunculus cerebri immediately in front of the third nerve, which separates it from the superior cerelsellar artery. After receiving the posterior communicating artery, which runs backward from the internal carotid, the posterior cerebral turns backward onto the under surface of the cerebral hemisphre, where it breaks up into branches for the supply of the temporal and occipital lobes.
Distribution of the Cerebral Arteries
Although the brain receives its blood supply from two distinct sources, namely, from the internal carotids and from the vertebrals, it is convenient to consider together the distribution of the various cerebral branches derived from these stems. The formation of the circulus arteriosus (circle of Willis) and the origin of the anterior, middle and posterior cerebral arteries has already been described (pp. 554, 561). The detailed distribution of these vessels will now be considered. In general, their branches may be divided into central or ganglionic and peripheral or cortical.
The anterior cerebral artery has but a hmited central distribution. It gives off a few inconstant branches which enter the anterior perforated substance and supply the anterior end of the caudate nucleus. One or two of these run to the corpus callosum and septum peUucidum. The anterior communicating branch is a transverse trunk which connects the two arteries and thereby completes the circulus arteriosus in front. It hes in front of the optic chiasm, and varies considerably in length and size. It may give off some of the branches to the anterior perforated substance. The cortical branches supply the gyrus rectus, the olfactory lobe and a part of the orbital gyri on the ventral surface. On the medial surface branches supply the cortex as far back as the parieto-occipital fissure. These branches are given off as the artery
Posterior communicating artery
curves around the corpus callosum and some of them curve over onto the lateral surface and supply the superior and middle temporal convolutions. Branches from the anterior cerebral artery also supply the corpus callosum (fig. 459).
The middle cerebral artery gives off most of the branches to the basal gangha and supplies the greater part of the lateral surface of the brain. It runs through the lateral fissure (fissure of Sylvius) (fig. 460). The branches of the middle cerebral include the following:
The central branches are: — (i) The caudate, two or three small branches, which arise from the medial aspect of the artery and pass through the medial part of the floor of the lateral fissure (fissure of Sylvius) to the head of the caudate nucleus, (ii) The antero -lateral are numerous small arteries which pass through the anterior perforated substance and supply the caudate nucleus (except its head), the internal capsule, and part of the optic thalamus, (iii) The lenticulostriate, a larger branch of the antero-latera! set, passes through a separate aperture in the lateral part of the anterior perforated substance, runs upward between the lenticular nucleus, which it supplies, and the external capsule, perforates the internal capsule, and terminates in the caudate nucleus. It has been so frequently found ruptured in apoplexy that it is called by Charcot the 'artery of cerebral haemorrhages.' (iv) Sometimes a more or less distinct branch, called lenticulo-optic, is distributed to the lateral and hinder portion of the lenticular nucleus and the lateral portion of the optic thalamus.
The cortical branches come off opposite the insula. They supply the insula, the inferior frontal gyri, the central gyri (anterior and posterior), the parietal lobules, superior and inferior, the supra-marginal, angular, and superior temporal g}T:i.
enter the posterior perforated substance and supply the medial portion of the optic thalamus, and the walls of the third ventricle; the posterior chorioid pass through the transverse fissure to the tela chorioidea (velum interpositum) and chorioid plexus; the postero-lateral run to the posterior part of the optic thalamus and give branches to the cerebral peduncles and the corpora quadrigemina.
In regard to the cerebral arteries in general it may be said that there is no anastomosis between the cortical and central branches, the two forming distinct and separate systems. The cortical may or may not anastomose with each other, but the communication between the neighbouring cortical branches is seldom sufficient to maintain the nutrition of an area when the vessel that normally supphes it is obstructed. The central branches are so-called endvessels and do not anastomose with each other. Hence obstruction of the middle cerebral artery leads to softening of the area suppUed by its central branches, but not always to softening of the region suppHed by its cortical branches. Indeed, the cortical region may escape completely, although the central area is irreparably disorganised. The gross anastomosis of the posterior cerebral with the anterior cerebral arteries through the circulus arteriosus has already been described. To sum up the distribution of the cerebral arteries, the branches of each are divided into the central, or ganglionic and the peripheral or cortical. The central branches arise at the commencement of the cerebral arteries about the cireulus arteriosus whilst the cortical are derived chiefly from the termination of these vessels.
Middle cerebral artery
(A) The central branches are divided into four sets — two median and two lateral. 1. The two median are — (1) The antero-median, which arise from the anterior cerebral and the anterior communicating, and supply the fore end of the caudate nucleus, and (2) the posteromedian, which arise from the posterior cerebral and supply the medial part of the optic thalamus and neighbouring wall of the third ventricle. 2. The two lateral are: — (1) The antero -lateral arise from the middle cerebral, and, passing through the anterior perforated substance, supply the lenticular nucleus, the posterior part of the caudate nucleus, the internal and external capsules, and the lateral part of the optic thalamus. (2) The postero-lateral arise from the posterior cerebral, and supply the hinder part of the optic thalamus, the pedunculus cerebri, and the corpora quadrigemina.
substance, some of which extend through it to the underlying white substance.
It will be seen that the middle cerebral supphes the somaesthetic area of the cortex. It also supphes the cortical auditory centre, and, in part, the higher visual centre. The anterior cerebral supphes only a small part of the somtesthetic area, namely, the part of the leg centre that occupies the paracentral lobule and the highest part of the anterior central gyrus. The posterior cerebral supphes the visual path from the middle of the tract backward, and the half vision centre in the occipital lobe. It supphes also the corpora quadrigemina and the sensory part of the internal capsule.
2. THE THYREOCERVICAL TRUNK
The thyreocervical trunk [truncus thyreocervicalis] or thyreoid axis arises from the upper and front part of the subclavian artery, usually opposite the internal mammary, and slightly medial to the scalenus anterior. It is a short thick trunk, and divides almost immecUately into three radiating branches — namely, the inferior thyreoid, the transverse scapular, and the transverse cervical (figs. 444, 457). This is the usual form only on the left side (see page 559). It may give off also the ascending cervical.
The inferior thyreoid artery [a. thyreoidea inferior] is the largest of the three branches into which the thyreocervical trunk (thyreoid axis) divides, and may arise in a common trunk with the transverse scapular, or as a branch of the subclavian. It ascends tortuously passing medially in front of the vertebral artery, the inferior laryngeal nerve and the longus colU muscle, and behind the common carotid and the sympathetic nerve or its middle cervical ganglion, to the thyreoid gland, where it anastomoses with the superior thyreoid artery and the artery of the opposite side.
with the tracheal branches of the superior thyreoid and bronchial arteries.
(4) The inferior laryngeal artery [a. laryngea inferior] passes along the trachea to the back of the cricoid cartilage in company with the inferior laryngeal nerve. It enters the larynx beneath the inferior constrictor. Its further distribution in that organ is described under Larynx.
(6) The ascending cervical artery [a cervicalis ascendens] (figs. 444, 457) is given off from the thyreocervical trunk or from the inferior thyreoid as that vessel is passing beneath the carotid sheath. It ascends between the scalenus anterior and the longus capitis (rectus capitis anterior major), lying parallel and medial to the phrenic nerve and behind the internal jugular vein. It anastomoses with the vertebral, ascending pharyngeal, and occipital arteries, and supphes branches to the deep muscles of the neck [rami musculares], to the spinal canal [rami spiuales], and to the phrenic nerve. Two veins accompany the ascending cervical artery and end in the innominate vein.
THE TRANSVERSE SCAPULAR ARTERY
The transverse scapular or suprascapular [a. transversa scapulae] artery passes laterally across the root of the neck, lying first beneath the sterno-mastoid, and then in the subclavian triangle behind the clavicle and subcalvius muscle. At the lateral angle of this space it is joined by the suprascapular nerve, sinks beneath the posterior belly of the omo-hyoid, and passes over the hgament bridging the scapular notch, the nerve passing through the notch (fig. 461). It then ramifies in the supraspinous fossa of the scapula, and, winding downward round the base of the spine over the neck of the scapula, enters the infraspinous fossa, and terminates by anastomosing with the circumflex (dorsal) scapular artery, and the descending branch of the transverse cervical (posterior scapular) artery.
As it lies under cover of the sterno-mastoid muscle, it crosses the phrenic nerve and the scalenus anterior; and as it courses through the subclavian triangle, it is separated by the cervical fascia which descends from the omo-hyoid to the first rib, from the subclavian artery and brachial plexus of nerves. If this artery is seen in tying the subclavian it should not be injured, as it is one of the chief vessels by which the collateral circulation is carried on after ligature of the subclavian in the third part of its course. At the lateral part of the subclavian triangle it is covered by the trapezius, and after passing over the transverse scapular Mgament it pierces the supraspinous fascia and passes beneath the supra-spinatus muscle, ramifying between it and the bone. In the infraspinous fossa it hes between the infra-spinatus and the bone. The artery is accompanied by two veins.
The branches of the transverse scapular are: — (1) the nutrient, to the clavicle; (2) the acromial [ramus acromialis] to the arterial rete or plexus on the acromial process, to reach which it pierces the trapezius; (3) the articular, to the acromio-clavicular joint and shoulderjoint; (4) the subscapular, given off as the artery is passing over the transverse scapular ligament, descends to the subscapular fossa between the subscapularis and the bone, and anastomoses with the infrascapular branch of the circumflex (dorsal) scapular artery, and with the subscapular and transverse cervical arteries; (5) the supraspinous branches, which ramify in the supraspinous fossa, and supply the supra-spinatus muscle and the periosteum, and the nutrient artery to the bone; (6) the infraspinous branches, which ramify in a similar way in the infraspinous fossa, giving off twigs to the infra-spinatus muscle, the periosteum, and the bone.
The tranverse cervical artery [a. transversa colli], somewhat larger than the transverse scapular (suprascapular), runs like the latter vessel laterally across the root of the neck, but on a slightly higher transverse plane, and a little above the clavicle. At its origin from the thyreo-cervical trunk (thyreoid axis) it lies under the sterno-mastoid; on leaving the cover of this muscle, it crosses the upper part of the subclavian triangle, lying here only beneath the platysma and cervical fascia; further laterally, it passes beneath the anterior margin of the trapezius and omo-hyoid muscle, and at the lateral margin of the levator scapulse divides into a descending (posterior scapular) and an ascending (superficial cervical) branch. In this course it crosses the phrenic nerve, the scalenus anterior, the brachial plexus, and the scalenus medius. Sometimes it passes between the cords of the brachial plexus.
The branches of the transverse cervical artery are: — (1) a descending (posterior scapular) ; and (2) an ascending (or superficial) cervical. The descending branch occasionally arises from the third portion of the subclavian artery.
(1) The descending branch, or posterior scapular [ramus descendens] the apparent continuation of the transverse cervical artery, begins at the lateral border of the levator scapula;, and, continuing its course beneath this muscle to the upper and posterior angle of the scapula, turns downward and skirts along the posterior border of the scapula, between the serratus anterior
(magnus) in front and the levator seapulEe and rhomboideus minor and major behind, to the inferior angle, where it anastomoses with the subscapular artery. It gives off the following branches: — (a) Supraspinous, which ramifies between the supraspinous muscle and the trapezius, and sends branches through the muscle into the fossa, to anastomose with the transverse scapular artery. (6) Infraspinous branches, one or more of which enter the infraspinous fossa, and anastomose with the circumflex (dorsal) scapular, (c) Subscapular branches, which enter the subscapular fossa, and anstomose with the branches of the transverse scapular and subscapular arteries, (d) Muscular branches, to the muscles between which it runs and to the latissimus dorsi. These branches anastomose with the posterior divisions of the intercostal arteries.
(2) The ascending branch or superficial cervical artery [r. asoendens], smaller than the descending branch, ascends under the anterior margin of the trapezius, lying upon the levator scapulae and splenius muscles. It supplies branches to the trapezius, levator scapulae, and splenius muscles, and the posterior chain of lymphatic glands. It anastomoses with the superficial branch of the descending branch of the occipital between the splenius and semispinahs capitis (complexus) . It is accompanied by two veins. This artery may arise directly from the thyreoid axis, or from the third part of the subclavian artery.
from the lower part of the first portion of the subclavian, usually opposite the
Fig. 462. — Scheme of the Right Internal Mammary Artery. It descends with a slight inclination forward and medialward, under cover of the clavicle, and enters the thorax behind the cartilage of the first rib, and thence passes down behind the cartilages of the next succeeding ribs, about 1.2 cm. (I in. ) from the lateral margin of the sternum, to the sixth interspace, where it divides into the superior epigastric and musculo-phrenic. It is accompanied by two veins, which unite into one trunk behind the first intercostal muscle; this
passes to the medial side of the artery into the corresponding vena innominata, or occasionally on the right side into the vena cava superior direct. The artery may be divided into two portions, the cervical and the thoracic.
The cervical portion is covered by the sterno-mastoid muscle, subclavian vein, and internal jugular vein, and is crossed obliquely, in the latero-medial direction, by the phrenic nerve. It rests upon the pleura and courses around the upper part of the innominate vein. There is no branch from this part of the artery.
The thoracic portion lies behind the cartilages of the six upper ribs, and in the interspace between the ribs has in front of it the pectoralis major and the internal intercostal muscles and external intercostal hgaments. Behind, it is in contact above with the pleura, but it is separated from it lower down by shps of the transversus thoracis (triangularis sterni). On the left side, the artery between the fourth and sixth ribs may be said to be in the anterior mediastinum, the pleura here forming a notch for the heart. In the first, second, and third spaces the artery, if wounded, can be easily tied; but in the fourth space the operation is attended with more difficulty. The remaining spaces are so narrow that a portion of the cartilage would have to be removed to expose the vessel.
The branches of the internal mammary artery are: — (l) The pericardiophrenic; (2) the anterior mediastinal and thymic; (3) the bronchial; (4) the pericardiac; (5) the sternal; (6) the anterior intercostals; (7) the perforating; (8) the lateral costal; (9) the superior epigastric; and (10) the musculo-phrenic.
(1) The pericardio-phrenic artery [a. pericaridiophrenica], is a long slender vessel which comes off from the internal mammary just after it has entered the chest, and descends with the phrenic nerve, at first between the pleura and innominate vein; then (on the right side) between the pleura and the vena cava superior ; and lastly, between the pleura and the pericardium to the diaphragm, where it anastomoses with the other diaphragmatic arteries. It gives branches both to the pleura and pericardium.
(2) The anterior mediastinal and thymic arteries [aa. mediastinales anteriores et thymicae] come off irregularly from the internal mammary. They are of small size, and supply the connective tissue, fat, and lymphatics in the superior and anterior mediastina and the remains of the thymus gland.
(6) The anterior intercostal branches [rami intercostales] (figs. 463, 478) — two in each of the five or six upper intercostal spaces — run laterally from the internal mammary artery, along the lower border of the rib above and the upper border of the rib below, and anastomose with the corresponding anterior and collateral branches of the aortic intercostals. Each pair of branches sometimes arises by a common trunk from the internal mammary, which in this case soon divides into an upper and a lower branch, as above described. They lie at first between the internal intercostal muscles and the pleura; afterward between the external and internal intercostal muscles. They supply the contiguous muscles, the pectoralis major, and the ribs.
(7) The perforating or anterior perforating branches [rami perforantes] — five or six in number, one corresponding to each of the five or six upper spaces — come off from the front of the internal mammary, between the superior and inferior anterior intercostals, and, perforating the internal intercostal muscles, pass forward between the costal cartilages to the pectoralis major, which they supply [rami musculares]. The terminal twigs perforate that muscle close to ttie sternum, and are distributed to the integument [rami cutanei]. The second, third, and fourth perforating supply the inner and deep surface of the mammary gland, and become greatly enlarged during lactation [rami mammaria]. They frequently require ligation in excision of the breast.
(8) The lateral costal branch [ramus costales lateralis] is given off close to the first rib, and descends behind the ribs just external to the costal cartilages. It anastomoses with the upper intercostal arteries. This vessel is often of insignificant size, or absent.
(9) The superior epigastric artery [a. epigastrica superior] (fig. 462), or medial terminal branch of the internal mammary artery, leaves the thorax behind the seventh costal cartilage by passing through the costo-xiphoid space in the diaphragm. It is the direct prolongation of the internal mammary downward. In the abdomen it descends behind the rectus muscle, between its posterior surface and its sheath, and, lower, entering the substance of the muscle, anastomoses with the inferior epigastric, a branch of the external iliac. It gives off the following small branches: — (o) The phrenic, to the diaphragm; (b) the xiphoid, which crosses in front of the xiphoid cartilage, and anastomoses with the artery of the opposite side; (c) the cutaneous, which perforate the anterior layer of the sheath of the rectus and supply the integuments; (d) the muscular, to the rectus muscle, some of which perforate the rectus sheath laterally, and are distributed to the obhque muscles; (e) the hepatic (on the right side only), which pass along the falciform ligament to the liver, and anastomose with the hepatic artery; (/) the peritoneal, which perforate the posterior layer of the sheath of the rectus, and ramify on the peritoneum.
(10) The musculo-phrenic artery [a. musculophrenica], or lateral terminal branch of the internal mammary artery, skirts laterally and downward behind the costal cartilages of the false ribs along the costal attachments of the diaphragm, which it perforates opposite the ninth rib. It terminates, much reduced in size, at the tenth or eleventh intercostal space by anastomosing with the ascending branch of the deep circumflex iUac artery. It gives off in its course the following small branches: — (a) The phrenic for the supply of the diaphragm; (b) the anterior intercostals, two in number for each of the lower five or six intercostal spaces, are dis-
tributed like those to the upper spaces, aheady described, and anastomose like them with the corresponding anterior branches of the lower aortic intercostals; (c) the muscular for the supply of the oblique muscles of the abdomen.
The costo-cervical trunk [truncus costocervicalis] (figs. 444, 463) is a short stem which arises usually from the back part of the second portion of the subclavian artery, behind the scalenus anterior on the right side, but commonly just medial to that muscle on the left side. Its course is upward and backward above the dome of the pleura and then downward toward the thorax, before entering which it divides into its two terminal branches.
(1) The superior intercostal [a. intercostahs suprema] (fig. 463) continues the direction of the costo-cervical trunk, passing downward into the thorax in front of the neck of the first rib. It sometimes terminates opposite the first intercostal space by becoming the first intercostal artery. Usually, however, it is prolonged downward over the neck of the second rib and supplies the second intercostal space in addition. It communicates with the highest aortic intercostal artery. As it crosses the neck of the first rib the superior intercostal lies anterior (ventral) to the first intercostal nerve and lateral to the superior thoracic ganghon of the sympathetic.
Intercostal vessels of fourth space
The branches to the first and second intercostal spaces resemble in course and distribution the succeeding intercostals derived from the thoracic aorta (see p. 588). Like the aortic intercostals they give off dorsal [rr. dorsales] and spinal branches [rr. spinalesj. An arteria aberrans, when present, arises from the medial side of the right superior intercostal, or occasionally from the right subclavian itself. It descends as a slender vessel into the thorax, passing downward and medially behind the oesophagus as far as the third or fourth thoracic vertebra, where in some cases it anastomoses with a similar slender branch arising from the aorta below the hgamentum arteriosum. This anastomosis represents the remains of the embryonic right dorsal aortic arch, and it is by its occasional enlargement that the anomaly of the right subclavian artery rising from the descending portion of the aortic arch occurs (see p. 637).
(2) The deep cervical artery [a. cervicahs profunda] passes directly backward, first between the seventh and eighth cervical nerves, and then between the transverse process of the seventh cervical vertebra and the neck of the first rib, having the body of the seventh cervical vertebra to its medial side, and the intertransverse muscle to its lateral side. It then tm'ns upward in the groove between the transverse and spinous processes of the cervical vertebrae lying upon the semispinaUs colh. It is covered by the semispinahs capitis (complexus). Between these muscles it anastomoses with the deep branch of the descending branch (princeps cervicis) of the occipital artery. It gives off a spinal branch which enters the vertebral canal through the intervertebral foramen with the eighth cervical nerve.
The term axillary is applied to that portion of the maia arterial stem of the upper limb that passes through the axillary fossa. The axillary artery [a. axillaris] (fig. 464) therefore is continuous -with the subclavian above and with the brachial below. It extends from the lateral border of the first rib to the lower edge of the teres major muscle, and has the shoulder-joint and the neck of the humerus to its lateral side. When the arm is placed close to the side of the body, the artery forms a gentle curve with its convexity upward; but when the arm is carried out from the side at right angles to the trunk in the ordinary dissecting position, the vessel takes a nearly straight course, which will then be indicated by a Hne drawn from the middle of the clavicle to the groove on the medial side of the coracobrachialis and biceps muscles. The axillary artery is at first deeply placed beneath the pectoral muscles, but in its lower third it is superficial, being covered
sal thoracic artery
only by the skin and the superficial fascia and deep fascia. It is divided into three parts, first, second, and third, according as it lies respectively above, beneath, or below the pectoralis minor.
in length.
Relations. — In front it is covered by the skin, superficial fascia, lower part of the platysma, the deep fascia, the pectorahs major, the coraco-clavioular (costo-ooracoid) fascia, the subclavius muscle and the clavicle when the arm hangs down by the side. The cephalic and thoraco-acromial veins, the external anterior thoracic nerve, and the axillary lymphatic trunk, cross over it. A layer of the deep cervical fascia which has passed under the clavicle also descends in front of it.
Behind, it rests upon the first intercostal space and first intercostal muscle, the first digitation and sometimes a portion of the second digitation of the serratus anterior (magnus) muscle, and a part of the second rib. The long thoracic nerve, on its way to the serratus anterior muscle, passes behind it.
The Third Part of the Axillary Artery
The third part of the axillary artery (fig. 464) extends from the lower border of the pectoralis minor to the lower border of the teres major. Its upper half lies deeply placed within the axilla, beneath the lower edge of the pectoralis major muscle, but its lower half is in the arm external to the axilla, and is uncovered by muscle. It measures about 7.5 cm. (3 in.) in length.
Relations. — In front it has, in addition to the skin and superficial fascia, the pectorahs major above, and lower down the deep fascia of the arm. It is crossed obhquely by the medial root of the median nerve and by the lateral brachial vena comitans.
Behind, it lies successively upon the subscapularis, the latissimus dorsi, and teres major muscles. From the first-named muscle it is separated at first by a considerable mass of fat and cellular tissue. The radial (musculo-spiral) and axillary (circumflex) nerves intervene between the artery and the muscles.
On its lateral side it is separated from the bone by the coraco-brachialis, by which it is partly overlapped, this muscle and the short head of the biceps serving as a guide to the artery in hgature. For a part of its course it has also the musculo-cutaneous nerve and the lateral root of the median nerve to its lateral side.
To its medial side it has the axillary vein, the ulnar nerve, the medial antibrachial (internal) and brachial (lesser internal) cutaneous nerves, and the medial root of the median nerve. The ulnar nerve is between the artery and the vein. The medial antibrachial (internal) cutaneous nerve is a httle in front of the artery as well as medial to it.
The branches of the axillary artery are exceedingly variable. In fig. 465 is shown what Hitzrot has found the usual type, in which the second portion of the artery has no named branches. The figure brings out the segmental relation of the branches of the axillary artery to the chest wall and suggests how one of the branches may supply the place of another. If the lateral thoracic arises directly from the axillary, it is generally from the second part as described below. In addition to the larger branches of the artery small twigs are supplied to the serratus anterior, coraco-brachialis, and subscapularis; also to the axillary lymphnodes.
thoraco-acromial, or a little above. It passes behind the axillary vein across the first intercostal space, supplying the intercostal muscles and the upper portion of the serratus anterior, and anastomoses with the intercostal arteries. At times it sends a branch between the pectoralis major and minor, which then, as a rule, more or less takes the place of the pectoral branch of the thoraco-acromial (figs. 464 and 465).
2. The thoraco-acromial or acromio-thoracic axis [a. thoracoacromialis] arises from the front part of the axillary just above the upper border of the pectoralis minor. It is a short trunk, and, coming off from the front of the artery, pierces the coraco-clavicular fascia, and then divides into three or four small branches, named from their direction: — (a) the acromial; (b) the deltoid; (c) the pectoral, and {d) the clavicular.
(a) The acromial branch [r. acromiaUs] or branches pass laterally across the coracoid process, frequently through the deltoid muscle, which they in part supply, to the acromion, where they form, by anastomosing with the anterior and posterior circumflex and transverse scapular (suprascapular) arteries, the so-called acromial rete, or plexus of vessels on the surface of that process.
(6) The deltoid branch [r. deltoideus] runs downward with the cephalic vein in the interval between the pectorahs major and the deltoid, and, supplying lateral ofTsets to these muscles and the adjacent integument, anastomoses with the anterior and posterior circumflex humeral arteries.
(c) The pectoral branch [r. pectorahs] passes between the pectorahs major and minor muscles, both of which it supplies. In the female, one or more branches which perforate the pectoralis major are often of large size, and supply the superimposed mammary gland.
muscle, and anastomoses with the transverse scapular artery.
3. The lateral thoracic artery [a. thoracalis lateralis] descends along the lower border of the pectoralis minor, under cover of the pectoralis major, to the chest wall. It supplies both pectoral muscles and the serratus anterior fmagnus), sends branches around the lower border of the pectoralis major to the mammary gland, and terminates in the intercostal muscles by anastomosing with the aortic intercostals and the internal mammary. It also furnishes branches to the lymph-nodes of the axillary fossa. The branches to the mammary gland in the female are often of large size.
downward and medial direction along the anterior border of that muscle under cover of the latissimus dorsi. It supplies the subscapularis, teres major, latissimus dorsi, and serratus anterior (magnus) muscles, and gives branches to the nodes in the axillary fossa. The course of this large vessel along the posterior border of the axillary fossa should be remembered in opening abscesses in the fossa, and in removing enlarged nodes from it. It is accompanied by two veins, which usually unite and then receive the circumflex (dorsal) scapular vein, and open as a single vein of large size either into the axillary or at the confluence of the medial brachial vena comitans with the basilic vein.
thoracic.
Fig. 466. — The Anastomoses about the Scapula. Subscapular branch of transverse scapular artery Supraspinous branch of transverse scapular artery
vical artery
(1) The circumflex scapular artery [a. circumflexa scapulae], or dorsal scapular, arising from the subscapular, usually at the point above mentioned, passes backward through the triangular space bounded by the subscapularis above, the teres major below, and the long head of the triceps laterally, and then between the teres minor and the axiUary border of the scapula, which it commonly grooves. It thus reaches the infraspinous fossa, where, under cover of the infra-spinatus, it anastomoses with the transverse scapular (suprascapular) artery and the descending branch of the transverse cervical (posterior scapular) (fig. 466). As it passes through the triangular space, it gives off a ventral branch which ramifies between the subscapularis and the bone, supplying branches to the subscapularis, to the scapula, and to the shoulderjoint. A second branch is often given off near the triangular space and passes downward between the teres major and teres minor, supplying both muscles (fig. 467).
(2) The dorsal thoracic artery [a. thoracodorsahs] continues in the course of the subscapular as far as the angle of the scapula, where it anastomoses with the circumflex scapular, the descending branch of the transverse cervical (posterior scapular), the lateral thoracic, and intercostal arteries.
5. The anterior circumflex humeral artery [a. circumflexa humeri anterior], usually quite a small vessel, comes off from the lateral side of the axillary artery, generally opposite the posterior circumflex. It passes beneath the coracobrachialis and short and long heads of the biceps, winding transversely round the front of the surgical neck of the humerus, across the intertubercular (bicipital) groove, and anastomoses ^vith the posterior circumflex and thoraco-acromial arteries. It gives off the following small branches:
(o) The bicipital or ascending, which runs up the intertubercular groove to supply the long tendon of the biceps and the shoulder-joint; and (h) a pectoral or descending branch, which runs downward along the insertion of the pectorahs major, and supplies the tendon of that muscle. The anterior circumflex artery, in consequence of its being close to the bone, is sometimes difficult to secure in the operation for excision of the shoulder-joint.
6. The posterior circumflex humeral artery [a. circumflexa humeri posterior] (fig. 467) arises from the posterior aspect of the axillary, just below the lower border of the subscapularis muscle. It passes through the quadrilateral space, bounded by the teres minor above, the latissimus dorsi and teres major below, the humerus laterally, and the long head of the triceps medially, and, winding round the back of the humerus beneath the deltoid, breaks up under cover of that muscle into a leash of branches, which for the most part enter its substance. The axillary (circumflex) nerve and two vense comitantes run with it. It anastomoses with the anterior circumflex, the arteries on the acromion, and the profunda artery.
In addition to the leash of vessels to the deltoid, it gives off the following small branches: — (a) nutrient, to the greater tuberosity of the humerus; (b) articular, to the back of the shoulderjoint; (c) acromial, to the plexus on the acromion; and [d) muscular, to the teres minor and long and short heads of the triceps. One or more of these branches to the triceps descend either between the lateral and long head or in the substance of that muscle, to anastomose with an ascending branch from the profunda artery. It is by means of this anastomosis that the collateral circulation is chiefly carried on when the axillary or the brachial artery is tied between the origins of the posterior circumflex and profunda arteries.
The brachial artery [a. brachialis] (fig. 468), the continuation of the axillary, extends from the lower border of the teres major to a little below the centre of the crease at the bend of the elbow, where it divides, opposite the junction of the head with the neck of the radius, into the radial and ulnar arteries. The artery is situated at first medial to the humerus; but as it passes down the arm it gradually gets in front of the bone, and at the bend of the elbow lies midway between the two epicondyles. Hence, in controlling hiemorrhage, the artery should be compressed laterally against the bone in its upper third, laterally and backward in its middle third, and directly backward in its lower third. Throughout the greater part of its course the artery is superficial, being merely overlapped slightly on
its lateral side by the coraco-brachialis and biceps muscles; but at the bend of the elbow it sinks deeply beneath the lacertus fibrosus of the biceps into the triangular interval (antecubital space) bounded on either side by the brachio-
radialis and pronator teres, and at its bifurcation is more or less under cover of these muscles (fig. 469). The sheath of the brachial artery is closely incorporated with the fascia covering the biceps muscle, and it is for this reason that in the operation for hgaturing the vessel is apt to be retracted with the muscle.
A line drawn from the groove medial to the coraco-brachialis and biceps muscles to midway between the epicondyles of the humerus will indicate its course. It is accompanied by two veins which frequently communicate across the artery. In addition to the branches named below the iDrachial artery gives off numerous muscular branches and, occasionally, the nutrient artery to the humerus. The muscular branches usualty come off from the lateral side of the artery; one in particular, which supplies the biceps muscle, is frequently of large size.
Relations. — In front, the artery is covered by the integument and superficial and deep fasciae, and at the bend of the elbow by the lacertus fibrosus of the biceps, and in muscular subjects by the overlapping margins of the brachio-radialis and pronator teres. In the middle third of the arm it is crossed obliquely from the lateral to the medial side by the median nerve, and at the bend of the elbow by the median cubital vein, the bicipital fascia intervening (fig. 475).
Behind, it lies successively on the long head of the triceps (from which it is separated by the radial (musculo-spiral) nerve and profunda artery), on the medial head of the triceps, on the insertion of the ooraco-braohialis, and thence to its bifurcation on the brachiahs muscle.
Lateral to the artery is the coraco-brachialis above, and the muscular belly of the biceps below, both of which shghtly overlap the vessel, and at the bend of the elbow the tendon of the biceps. The lateral vena comitans is also to its lateral side. The median nerve is in close contact with the lateral side of the artery in the upper third of its course, but in the middle third crosses the artery obliquely to gain the medial side.
Medial to the artery in the upper part of its course are the medial antibrachial (internal) cutaneous and the ulnar nerves; the latter nerve, however, leaves the artery about the origin of the ulnar collateral (inferior profunda) branch, to make, with that vessel, for the medial epicondyle. Lower down, the medial antibrachial cutaneous nerve also leaves the artery, by piercing the deep fascia. The median nerve is in close contact with the medial side of the artery in its lower third and at the bend of the elbow. The basilic vein is superficial to it, and a Uttle to its medial side in the greater part of its course, but separated from it by the deep fascia. The medial vena comitans runs along its medial side.
The profunda brachii (superior profunda) is the largest branch of the brachial. It arises from the medial and hinder aspect of that artery, a Httle below the inferior border of the tendon of the teres major. It at first lies to the medial side of the brachial, but soon passes behind that vessel, and, sinking between the medial and long heads of the triceps with the radial (musculo-spiral) nerve, curves around the humerus in the groove for the nerve, lying in contact with the bone between the medial and lateral heads of the triceps. On reaching the lateral supracondyloid ridge of the humerus it perforates the lateral intermuscular septum, and, continuing forward between the brachio-radialis and brachialis to the front of the lateral epicondyle, ends by anastomosing with the radial recurrent artery (figs. 468 and 474).
(a) The deltoid branch [r. deltoideus] which may also arise from the brachial itself or from the superior ulnar collateral. It runs across the anterior surface of the humerus, under cover of the coraco-brachialis and biceps, and suppUes the brachiahs and deltoid.
The superior ulnar collateral artery [a. collateralis ulnaris superior] (inferior profunda) arises from the medial side of the brachial, usually about the level of the insertion of the coraco-brachialis, at times as a common trunk with the profunda. It passes with the ulnar nerve medially and downward through the medial intermuscular septum, and then along the medial head of the triceps to the back of the medial epicondyle, where, under cover of the deep fascia and the origin of the flexor carpi ulnaris from the olecranon and medial epicondyle, it enters into the anastomoses around the elbow-joint. It frequently supplies the nutrient artery to the humerus. It gives branches to the triceps, to the elbowjoint, and a branch which passes in front of the medial epicondyle to anastomose with the anterior ulnar recurrent.
The inferior ulnar collateral artery [a. collateralis ulnaris inferior] or anastomotica magna arises from the medial side of the brachial, about 5 cm. (2 in.) above its bifurcation into the radial and ulnar arteries, and, running medially and downward across the brachialis, divides into two branches, a posterior and an anterior. The posterior pierces the medial intermuscular septum, winds round the medial condyloid ridge of the humerus, and pierces the triceps, between which and the bone it anastomoses with the articular branch of the profunda artery, and to a lesser extent with the interosseous recurrent, forming an arterial arch or rete around the upper border of the olecranon fossa. The anterior branch passes medially and downward between the brachialis and pronator teres, and anastomoses in front of the medial epicondyle, but beneath the pronator teres, with the anterior ulnar recurrent. From this branch a small vessel passes down behind the medial epicondyle to anastomose with the posterior ulnar recurrent and superior ulnar collateral arteries (fig. 474).
The ulnar artery [a. ulnaris] (fig. 470) the larger of the two terminal branches of the brachial, begins opposite the lower border of the head of the radiusin the middle fine of the forearm. Thence through the upper half of the forearm it runs
beneath the pronator teres and superficial flexor muscles, and, having reached the ulnar side of the arm about midway between the elbow and the wrist, it passes directly downward, being merely overlapped by the flexor carpi ulnaris. Crossing the transverse carpal (anterior annular) ligament immediately to the radial side of the pisiform bone, it enters the palm, where it divides into two branches, which enter respectively into the formation of the superficial and deep volar arches. The artery is accompanied by two veins, which anastomose with each other by frequent cross branches, and usually terminate in the brachial venae comitantes. The ulnar nerve is at first some distance from the artery, but approaches the vessel at the junction of its upper and middle thirds, and then lies close to its medial or ulnar side. The course of the artery in the lower two-thirds of the forearm is indicated by a line drawn from the front of the medial epicondyle to the radial side of the pisiform bone; and in the upper third of the forearm by a line drawn in a gentle curve with its convexity to the medial side from 2.5 cm. (1 in.) below the centre of the bend of the elbow to a point in the former line at the junction of its upper with its middle third. The artery throughout its course is best reached through the interval between the flexor carpi ulnaris and the flexor digitorum sublimis.
In front. — In the upper half of the forearm the ulnar artery is deeply placed beneath the pronator teres, the flexor carpi radialis, the palmaris longus, and the flexor digitorum sublimis. In the lower half it is comparatively superficial, being merely overlapped above by the tendon of the flexor carpi ulnaris, whilst the last inch or so of the vessel is only covered as a rule by the skin and superficial and deep fasciae. As the artery hes beneath the pronator teres, it is crossed from the medial to the lateral side by the median nerve, the deep head of origin of the muscle usually separating the nerve from the artery. The lower part of the artery is crossed by the palmar cutaneous branch of the ulnar nerve.
Behind. — For about 2.5 cm. (1 in.) of its course the artery lies upon the brachialis; but thence, as far as the transverse carpal (anterior annular) ligament, upon the flexor digitorum profundus, which separates it above from the interosseous membrane and bone, and at the wrist from the pronator quadratus. The artery is bound down to the flexor digitorum profundus by bands of fasciae.
To the medial side in the lower two-thirds is the flexor carpi ulnaris, the guide to the vessel. The ulnar nerve, as it enters the forearm from behind the medial epicondyle, is at first some distance from the artery, being separated from it in its upper third by the flexor digitorum subhmis, but in its lower two-thirds is in close contact with the vessel and on its ulnar side.
5. Volar ulnar carpal.
1. The ulnar recurrent arteries [aa. recurrentes ulnares] are two, the volar, and dorsal. The volar is a small branch which arises from the medial side of the ulnar artery, or the dorsal ulnar recurrent, and, running between the lateral edge of the pronator teres and the brachiahs. anastomoses in front of the medial epicondyle with the inferior and superior ulnar collaterals. It supphes branches to the muscles between which it runs, and to the skin. The dorsal, larger than the volar, comes'off from the medial side of the ulnar artery, either a little below the latter branch, or else as a common trunk with it, and, passing between the flexores digitorum subhmis and profundus, turns upward to the back of the medial epicondyle, where it Ues with the ulnar nerve between the two heads of origin of the flexor carpi ulnaris. It supplies the contiguous muscles — the flexor carpi ulnaris, the palmaris longus, and the flexores digitorum sublimis and profundus — the elbow-joint, and the ulnar nerve, and anastomoses with the inferior and superior ulnar collaterals, and with the interosseous recurrent forming the so-called rete olecrani.
2. The common interosseous artery [a. interossea communis] is a short thick trunk 1.2 cm. (| in.) or so in length, which comes off from the lateral and back part of the ulnar artery about 2.5 cm. ( 1 in.) from its origin, and just before that artery is crossed by the median nerve. It passes backward and downward between the flexor pollicis longus and the flexor digitorum profundus, toward the triaagular interval bounded by the upper border of the interosseous membrane, the oblique hgament, and the lateral border of the ulna, where it divides into the volar and dorsal interosseous arteries.
The volar interosseous artery is accompanied by two veins and by the deep branch of the median nerve which hes to its radial side. The artery is bound down to the interosseous membrane by aponeurotic fibres.
Proper volar digital arteries
The branches of the volar interosseous artery are: — (i) The median artery [a. mediana] is a long slender vessel which arises from the volar interosseous immediately after the latter is given off from the common trunk. It passes forward between the flexor digitorum profundus and the flexor pollicis longus to the median nerve, with which it descends beneath the transverse carpal (anterior annular) ligament into the palm, and when of large size sometimes enters into the formation of the superficial palmar arch. At times the artery arises from the common
interosseous before its division, (ii) The nutrient arteries of the radius and uhia are usually derived from this vessel, (iii) The volar terminal division of the volar interosseous artery passes either in front of or behind the pronator quadratus, but in either case in front of the interosseous membrane, and anastomoses with the volar carpal branches of the radial and ulnar arteries, and with the recurrent branches from the deep volar arch, forming the so-called volar carpal rete. (iv) The dorsal terminal, the larger division, pierces the interosseous membrane, and continues its course downward behind the interosseous membrane, under cover of the extensor muscles, to the back of the wrist, where it ends by anastomosing with the dorsal
(6) The dorsal interosseous artery [a. interossea dorsalis], the larger division of the common interosseous, turns backward through the triangular interval bounded by the interosseous membrane below, the oblique hgament above, and the ulna on the medial side, and emerging at the back of the forearm between the abductor pollicis longus and the supinator, under cover of the superficial extensors of the forearm, descends between the superficial and the deep muscles, crossing in this course the abductor polhcis longus, the extensor pollicis brevis, the extensor pollicis longus, and the extensor indicis proprius (fig. 471). It anastomoses at the lower border
of this muscle and just above the wrist joint, with the dorsal branch of the volar interosseous which here, as above described, has perforated the interosseous membrane. It is separated from the deep radial nerve at first by the radius and supinator, and on the back of the forearm by the extensores polUcis longus and indicis proprius.
The chief branch of the dorsal interosseous artery, the interosseous recurrent artery [a. interossea recurrens] arises from the dorsal interosseous as the latter emerges from beneath the supinator. It runs upward between the anconeus and supinator, usually under cover of the former, to the interval between the lateral epicondyle and the olecranon, where it anastomoses with the profunda, inferior ulnar collateral, radial recurrent, and dorsal ulnar recurrent arteries, and gives branches to the retiform plexus over the olecranon — the rete olecrani.
4. The dorsal ulnar carpal [ramus carpeus dorsafis] comes off from the ulnar artery a little above the transverse carpal (anterior annular) ligament, and, winding medially round the end of the ulna or the ulnar collateral ligament of the wrist, beneath the flexor carpi ulnaris, ramifies on the back of the carpus beneath the extensor tendons. It forms by its anastomosis with the dorsal radial carpal, with the dorsal terminal branch of the volar interosseous and with the dorsal interosseous arteries a plexus or rete, the so-called dorsal carpal rete. The branches given off from this plexus or arch are described with the dorsal carpal branch of the radial artery.
5. The volar ulnar carpal [ramus carpeus volaris] is a small branch given off from the ulnar artery opposite the carpus. It passes beneath the flexor digitoruro profundus to anastomose with the volar radial carpal, with terminal twigs of the volar branch of the volar interosseous, and with recurrent branches from the deep volar arch, forming an anastomotic arch across the front of the carpus — the volar carpal arch or rete.
The ulnar artery at the wrist may be said to extend from the upper to the lower border of the transverse carpal (anterior annular) ligament upon which it rests. It here lies immediately to the radial side of the pisiform bone, and to the ulnar side of the hook of the hamate (unciform), the two bones forming for the vessel a protecting channel, which is further converted into a short canal by the expansion of the flexor carpi ulnaris passing from the pisiform to the hook of the hamate (unciform). The ulnar nerve in this situation is immediately to the ulnar side of the artery.
ficial and deep.
The superficial branch (fig. 472) , the direct continuation of the vessel, anastomoses with the superficial volar, a branch of the radial, forming what is then known as the superficial volar arch. After descending a short distance toward the cleft between the fourth and fifth fingers, it turns toward the thumb, forming a curve with its convexity toward the fingers and its concavity toward the muscles of the thumb, and anastomoses opposite the cleft between the index and middle fingers, at the junction of the upper with the middle third of the palm, with the superficial volar branch of the radial artery to complete the arch. A line drawn transversely across the palm on a level with the metacarpo-phalangeal joint of the thumb will roughly indicate the situation of the arch.
Relations. — In front: in addition to the skin and superficial fascia, the vessel is crossed successively, by the palmaris bevis, the palmar branch of the ulnar nerve, the palmar aponeurosis and the palmar branch of the median nerve.
The common digital arteries [aa. digitales volares communes]. These, usually four in number, arise from the conve.xity of the superficial arch and, running downward through the palm, give off the digital arteries proper to both sides of the httle, ring, and middle fingers, and the ulnar side of the index finger. The radial side of the index finger and the thumb are supplied by the first volar metacarpal branch" of the radial artery.
The most ulnar of the common digital arteries passes distally over the muscles in the ulnar border of the palm, and thence along the ulnar bordet of the httle finger. The remaining arteries pass distaUy in the three ulnar intermetacarpal spaces to within about 6 mm. (j in.) of the clefts between the fingers, where they divide into branches, the digital arteries proper [aa. digitales volares proprise], which supply the sides of contiguous fingers.
As the common digital arteries pass through the palm, they lie between the flexor tendons, on the digital nerves and lumbrical muscles, and beneath the palmar aponeurosis. Just before bifurcating they pass under the transverse fasciculi, and are joined b}^ the volar metacarpal branches from the deep volar arch (fig. 472). At this spot they also receive the volar perforating branches from the dorsal metacarpal vessels. On the sides of the fingers the proper digital arteries lie between the palmar and dorsal digital nerves. They anastomose by small branches, forming an arch across the front of the bones on the proximal side of each interphalangeal joint. They supply the flexor tendons and the integuments, and terminate in a plexiform manner beneath the pulp of the finger and around the matrix of the nail. A dorsal digital branch is given off to the back of the fingers about the level of the middle of the first phalanx, and a second but smaller dorsal digital branch about the level of the middle of the second phalanx.
The deep branch of the ulnar artery, also called the communicating artery, sinks deeply into the palm between the abductor and flexor quinti digiti brevis, and joins the radial to form the deep volar arch. (See The Radial Artery.)
The radial artery — the smaller of the two arteries into which the brachial divides at the bend of the elbow — appears as the direct continuation of the brachial. It runs, at first curving laterally, along the radial side of the forearm as far as the styloid process, then, coiling over the radial collateral ligament and the lateral and back part of the wrist, enters the palm of the hand from behind between the first and second metacarpal bones, and ends by anastomosing with the deep branch of the ulnar to form the deep volar arch. Hence the artery is divisible into three parts: that in the forearm, that at the wrist, and that in the palm of the hand. The course of the artery is indicated by a line drawn from a point 2.5 cm. (1 in.) below the centre of the elbow to a point situated just medial to the styloid process of the radius.
Relations. — In front, the artery is at first overlapped by the brachio-radialis, but for the rest of its course it is merely covered by the slcin, superficial and deep fascise, by some cutaneous veins, and by cutaneous branches of the musculo-cutaneous nerve.
Behind, it lies successively from above downward on the tendon of the biceps, the supinator, from which it is separated by a layer of fat, the insertion of the pronator teres, the radial origin of the flexor digitorum sublimis, the flexor poUicis longus, the pronator quadratus, and the volar surface of the lower end of the radius. It is in this last situation, where the artery Ues upon the bone and can therefore be easily pressed against it, that the pulse is usually felt.
Deep volar arch
On its lateral side it has, throughout the whole of its course, the braohio-radiahs muscle, the guide to the artery in ligature, and the lateral vena comitans; in its middle third, the superflcial radial nerve as well. In its lower third the superficial radial nerve is to its lateral side, but separated from it by the brachio-radialis and fascia.
(1) The radial recurrent [a. recurrens radialis] usually arises from the lateral side of the radial just below its origin from the brachial. It at first runs laterally on the supinator and then divides into three chief branches (fig. 475). One of these continues laterally through the fibres of the radial (musculo-spiral) nerve, or between the superficial (radial) and deep radial (posterior interosseous) nerves when the radial (musculo-spiral) divides higher than usual, into the brachioradiaUs and extensor carpi radiahs longus and brevis, and anastomoses with the interosseous recurrent. A second ascends between the brachiahs and braehio-radiahs, with the radial
(musculo-spiral) nerve, and anastomoses with the profunda artery. A third descends with the superficial radial nerve under cover of the brachio-radialis, supplying that muscle. The radial recurrent also gives off branches to the elbow-joint.
(3) The volar radial carpal branch [ramus carpeus volaris] arises from the rnedial side of the radial artery about the level of the lower border of the pronator quadratus. It crosses the front of the radius beneath the flexor muscles, and anastomoses with the volar carpal branch of the ulnar, forming the volar carpal rete. This plexus is joined above by terminal twigs from the volar interosseous artery, and below by recurrent branches from the deep volar arch. It supplies branches to the lower end of the radius, and to the wrist and carpal joints.
(4) The superficial volar branch [ramus volaris superficialis] leaves the radial artery as the latter vessel is about to turn over the radial collateral ligament to the back of the wrist. It courses forward over the short muscles of the ball of the thumb, and anastomoses with the superficial.
branch of the ulnar artery to complete the superficial volar arch. It supplies small branches to the muscles of the ball of the thumb, and frequently terminates in these muscles without ioining the arch. Occasionally it passes beneath the abductor poUicis brevis.
II. The Eadial Artery at the Wrist
The radial artery at the wrist winds over the radial side of the carpus, under the extensor tendons of the thumb, from a spot a little below and medial to the styloid process of the radius to the base of the first interosseous space, where it sinks between the two heads of the first dorsal interosseous muscle into the palm, to form, by anastomosing with the deep branch of the ulnar artery, the deep volar arch. A line drawn from 1.2 cm. (| in.) medial to the styloid process to the base of the first interosseous space, which can be distinctly felt on the back of the hand, will roughly indicate the course of the artery (fig. 476).
Relations. — The artery is covered successively by the abductor poUicis longus and extensor pollicis brevis, by branches of the superficial radial nerve and veins, and, just before it sinks between the two heads of the interosseous muscle, by the tendon of the extensor pollicis longus. The branches of the superficial radial nerve to the thumb and index finger cross it. It is at first somewhat deeply placed beneath the first-mentioned extensor muscles of the thumb; but subsequently it lies quite superficial, and can be felt pulsating in a fittle triangular depression bounded on either side by the extensores pollicis longus and brevis, and above by the lower end of the radius. The artery lies successively on the radial collateral ligament of the wrist, on the navicular (scaphoid), the greater multangular (trapezium), the base of the first metacarpjal bone, and on the dorsal ligaments uniting these bones. It has usually with it two companion veins, and a few branches of the musculo-cutaneous nerve.
(1) The dorsal radial carpal branch [ramus carpeus dorsaUs] arises from the radial as the latter vessel passes under the abductor pollicis longus, and runs medially beneath the extensor carpi radiahs longus and brevis, and the extensor pollicis longus, across the dorsal surface of the carpus, to anastomose with the dorsal ulnar carpal and with the terminal twigs of the posterior branch of the volar interosseous artery. This anastomosis is called the dorsal carpal
rete [rete carpi dorsale]. From this rete are given oif the second, third, and fourth dorsal metacarpal arteries to the second, third, and fourth intermetacarpal spaces respectively. These vessels run downward on the dorsal interosseous muscles as far as the flexure of the fingers, and there divide into two branches (dorsal digital), which run along the sides of the contiguous fingers on their dorsal aspect. Near their proximal ends they anastomose with the dorsal perforating branches of the deep volar arch. Distally they are connected by volar perforating branches with the digital arteries or the corresponding spaces. The branches which run along the backs of the fingers anastomose with the dorsal branches of the first dorsal digital arteries derived from the volar common digital vessels (fig. 476).
(2) The first dorsal metacarpal (figs. 472, 476) is given off by the radial shortly before it passes between the two heads of the first dorsal interosseous muscle. It quickly divides into two branches which supply the dorsal surface of the thumb and the radial side of the indexfinger toward its dorsal surface.
The radial artery enters the palm between the first and second metacarpal bones at the base of the first interosseous space, by passing between the two heads of the first dorsal interosseous muscle. It then runs medially between the transverse and oblique heads of the adductor pollicis muscle and continuing its course in a slight curve with the convexity forward, across the base of the metacarpal bones and interosseous muscles, it anastomoses with the deep branch of the ulnar, forming the deep volar arch [arcus volaris profundus]. The arch may be said to extend from the first interosseous space to the base of the metacarpal bone of the little finger, and is a finger's breadth nearer the wrist than the superficial arch. It is covered by the superficial and deep fiexor tendons, by the superficial head of the flexor pollicis brevis, and by part of the flexor quinti digiti brevis. It is accompanied by the deep branch of the ulnar nerve, and two small venae comitantes (figs. 472, 473).
The branches of the deep volar arch are: — (1) The princeps pollicis; (2) the radialis indicis; (5) the volar metacarpals (three in number); (4) the recurrent carpal; (3) the dorsal perforating. The first two are usually spoken of as coming off from the radial artery in the palm; the last three from the deep volar arch.
(1) The arteria princeps pollicis arises from the radial artery as it enters the palm between the two heads of the first dorsal interosseous muscle. It passes downward between the adductor pollicis transversus and the first dorsal interosseous muscle, parallel to the metacarpal bone, and between the two portions of the flexor polhcis brevis under cover of the flexor polUcis longus. Opposite the metacarpo-phalangeal joint it usually divides into two branches, one of which is distributed to each side of the thumb on its volar aspect. These vessels anastomose with each other at the end of the thumb, like the other digital arteries.
(2) The arteria radialis indicis comes off from the radial artery a little lower than the former vessel, or as a common trunk with it, and passes forward between the first dorsal interosseous and adductor pollicis transversus, parallel to the radial side of the second metacarpal bone. After emerging from beneath the adductor poUicis transversus it continues its course along the radial side of the index-finger, on its volar aspect, as far as the tip, anastomosing in this course with the digital artery on the opposite side of the finger in a way similar to that of the other digital arteries. It frequently communicates, at the lower border of the adductor pollicis, with the superficial volar arch and princeps pollicis. It gives off a dorsal branch, which anastomoses with the branch fron the fu-st dorsal metacarpal to the index finger.
(3) The volar metacarpal arteries [aa. metacarpex volares], three in number, come off from the convexity of the deep arch, and, coursing downward in the centre of the second, third, and fourth interosseous spaces on the interosseous muscles, terminate near the cleft of the fingers by anastomosing with the digital arteries from the superficial arch. These vessels supply the interosseous muscles and the bones, and the second, third, and fourth lumbricales.
(4) The recurrent branches come off from the concavity of the arch, and consist of two or three small vessels which run upward toward the wrist, and anastomose with the volar branch of the volar interosseous, and the volar radial and ulnar carpal arteries.
(5) The dorsal perforating brandies (rr. perforantes), which are usnally three in number, pass from the arch directly through the second, third, and fourth interosseous spaces between the two heads of the corresponding dorsal interosseous muscle, and join the proximal ends of the first dorsal interosseous, and the second, third, and fourth dorsal metacarpal arteries respectively.
The thoracic aorta [aorta thoracalis] (fig. 477) is the thoracic portion of the aorta descendens. It extends from the termination of the aortic arch at the lower border of the body of the fourth thoracic vertebra to the lower border of the body of the twelfth thoracic vertebra, where it passes between the medial
crura of the diaphragm, and is thence continued under the name of the abdominal aorta. It is at first situated a little to the left of the vertebral column, but as it descends, approaches the front of the column, at the same time following the backward curve of the spine, and at the diaphragm is almost in the middle line. It lies in the posterior mediastinum, having the oesophagus at first a little to the right of it, then in front of it, and just above the tenth thoracic vertebra, where this tube pierces the diaphragm, a little to its left side.
oesophagus, which separates it from the pericardium and heart, and by the diaphragm.
Behind, it hes upon the lower seven thoracic vertebrae, and is crossed obhquely opposite the seventh or eighth thoracic vertebra by the the vena hemiazygos (azygos minor) and opposite the fifth or sixth vertebra by the accessory hemiazygos vein, or by one or more of the intercostal veins.
Branches of the Thoracic Aorta
The branches of the thoracic aorta may be divided into the visceral and the parietal. The visceral are: — (1) The pericardiac; (2) the bronchial; and (3) the oesophageal. The parietal are: — (1) The intercostal; (2) the superior phrenic; and (3) the arteria aberrans.
A. Visceral Branches
(1) The pericardiac branches [rami pericardiaci] — two or three small branches, irregular in their origin, course, and distribution — pass to the posterior surface of the pericardium to supply that structure, and anastomose with the other pericardiac branches. They give small twigs to the posterior mediastinal glands.
(2) The bronchial arteries [aa. bronchiales] supply the bronchi and the lung substance. They vary considerably in their origin, course, and distribution; they are usually three in number — one on the right side, and two on the left.
(a) The right bronchial generally arises either from the first right aortic intercostal, or else as a common trunk witli the left upper bronchial from the front of the aorta just below the level of the bifurcation of the trachea. It passes laterally on the back of the right bronchus, and is distributed to the bronchi and lung substance, (b) The left upper bronchial arises from the front of the aorta just below the bifurcation of the trachea, or as a common trunk with the right bronchial, (c) The left lower bronchial arises from the front of the aorta just below the level of the left bronchus. Like the corresponding artery on the right side, the left bronchial arteries run laterally on the left bronchus, and, after dividing and subdividing on the back of the bronchi, supply the bronchi themselves and the lung substance. Small twigs are given off from the bronchial arteries to the bronchial glands and to the oesophagus.
(3) The oesophageal arteries [aa. oesophageae], four or sometimes five in number, arise at intervals from the front of the descending thoracic aorta, the first coming off just below the left lower bronchial. They usually increase in size from above downward, the upper coming off more toward the right side of the aorta, the lower more toward the left side. They pass forward to the oesophagus, supplying that tube and anastomosing with each other and with the descending oesophageal branches of the inferior thyreoid above, and with the ascending oesophageal branches of the phrenic and gastric arteries below, thus forming a chain of anastomoses along the whole length of the tube.
(1) The intercostal arteries [aa. intercostal es], usually ten in number on each side, supply the lower intercostal spaces, the two upper spaces (occasionally the first only) being supplied from the costo-cervical trunk of the subclavian artery. The lowest artery accompanies the twelfth thoracic nerve below the last rib and is therefore called the subcostal artery. Its distribution is similar to that of the lumbar arteries (p. 593) except that it commonly crosses the anterior surface, rather than the posterior, of the quadratus lumborum.
The intercostals arise in pairs from the back part of the aorta, and at once turning, the one to the right, the other to the left, wind backward over the front and sides of the vertebral bodies to reach the intercostal spaces. In foetal life these arteries run almost transversely backward, or even with a slight inclination downward, to the intercostal spaces; but after the first year, in consequence of the disproportionate growth of the aorta and vertebral column, the upper int-ercostals have to ascend to reach their respective spaces.
The arteries in their course around the vertebrae differ on the two sides of the body. On the right side the arteries — and especially the upper, in consequence of the aorta lying a little to the left side of the spine in the upper part of its course — are longer than the left. They wind over the front and right side of the vertebrae, being crossed by the thoracic duct and vena azygos (major), and covered by the right pleura and lung. The upper are also crossed by the oesophagus. They give off small branches to the bodies of the vertebrae and anterior longitudinal Hgament. On the left side, as the intercostals wind around the sides of the bodies of the vertebrae, the lower are crossed by the vena hemiaz3rgos (azygos minor), the two upper by the left superior intercostal vein, and the two next by
(a) The anterior branches [rami anteriores] at first cross the intercostal space obliquely, in consequence of the downward direction of the ribs, toward the angle of the rib above, and thence are continued forward in the costal groove, and anastomose with the superior branches of the anterior intercostals from the internal mammary in the upper spaces, and from the musculo-phrenic in the lower spaces. They he at first on the external intercostal muscles, being covered in front by the pleura and lung, the endothoracic fascia, and the subcostal muscles. Opposite the heads of the ribs they are crossed by the sympathetic nerve. At the angle of the ribs they pass under cover of the internal intercostal muscles, and thence to their termination he between the two intercostal muscles. Their situation in the midspace as far as the angle of the rib should be remembered in performing paracentesis thoracis. To avoid the risk of injuring the vessels, the puncture should not be made further back than the angle of the ribs. They are accompanied by a nerve and vein, the vein lying above and the nerve below, except in the upper spaces, where the artery, having to ascend to reach the space, at first Mes below the nerve which runs more horizontally. The uppermost branch anastomoses with the costo-oervical artery from the subclavian, and at times supplies almost entirely the second intercostal space. The arteries to the tenth and eleventh spaces on reaching the end
of anterior intercostal
of their respective ribs pass between the abdominal muscles, and anastomose with the inf. epigastric artery from the external ihac, and with the lumbar arteries from the abdominal aorta. The artery beneath the twelfth rib anastomoses with the lumbar arteries and with the external circumflex ihac.
Each anterior branch gives off the following: — (i) The collateral branch which comes off near the angle of the rib and runs forward, between the external and internal intercostals, along the upper border of the lower rib enclosing the space. It is smaller than the main anterior branch and anastomoses with tlie lower anterior intercostal in each space, (ii) Muscular branches [rami nmsculares] supply the intercostal, pectoral and abdominal muscles, (iii) The lateral cutaneous branches [rami cutanei laterales], both pectoral and abdominal, run with the corresponding branches of the intercostal nerves through the external intercostal and serratus anterior muscles. They then divide into anterior and -posterior branches which turn forward and backward, respectively, to supply the integument. The anterior branches from the third, fourth and fifth spaces supply lateral mammary branches [rr. mammarii laterales] to the lateral region of the breast, (iv) Anterior cutaneous branches [rami cutanei anteriores] pierce the external intercostal ligament and the pectorahs major just lateral to the sternum.
to the medial region of the breast.
(b) The posterior branches [rami posteriores]. — These large branches are given oil from the intercostals opposite the quadrilateral space bounded by the transverse process of the vertebra above, the neck of the rib below, the body of the vertebra medially, and the anterior costotransverse ligament laterally. Passing backward toward this space with the dorsal branch of the corresponding intercostal nerve, they divide opposite the intervertebral foramen into a muscular and a spinal branch, (i) The muscular branch [r. muscularis] passes backward through the quadrilateral space, and soon subdivides into a medial and a lateral branch. The former passes between the longissimus dorsi and iUo-costaUs, and, after supplying these muscles, gives off medial cutaneous branches [rr. cutanei mediales]. The latter branch pierces the multifidus spinas, and, emerging between the longissimus dorsi and semispinahs dorsi near the spinous processes, gives off lateral cutaneous branches [rr. cutanei laterales]. It suppHes the muscles ■ in its course.
(ii) The spinal branch [r. spinalis] enters the intervertebral foramen with the spinal nerve of the corresponding segment. The disposition of the spinal branch is similar to_ that of the spinal branches entering the canalis vertebralis in other regions and may be described here: —
ARTERIES OF THE VERTEBRAL CANAL
Spinal arteries are derived from the vertebral, ascending cervical and costo-cervical arteries, from the dorsal rami of the intercostal (fig. 478) and lumbar arteries, and from the ilio-lumbar and lateral sacral arteries. The spinal branch in each case divides into three branches, postcentral, prelaminar and neural.
Each post-central branch divides on the lateral part of the posterior longitudinal ligament into an ascending and a descending branch by which means a bilateral series of anastomosing arches are formed throughout the length of the canal. From the concavities of the opposite arches transverse connecting stems are formed which are again connected by a median longitudinal channel.
The neural branches enter the dura mater and are usually small and end by supplying the nerve roots. A variable number of these (5-10 on a side) are larger than the others and reinforce the longitudinal anterior and posterior spinal arteries given off from the vertebrals within the cranium. (For arteries of the spinal cord, see Section VII.)
(2) The superior phrenic arteries [aa. phrenicse superiores], are small twigs coming off from the thoracic aorta immediately above the diaphragm. They are distributed to the vertebral portion of the diaphragm on its upper surface.
(3) The arteria aberrans is a small twig which, arising from the thoracic aorta near the right bronchial artery, passes upward and to the right behind the oesophagus and trachea, and is occasionally found to anastomose on the oesophagus with the arteria aberrans of the superior intercostal artery (see p. 568). It is regarded as the remains of the right aortic dorsal stem (fig. 506).
THE ABDOMINAL AORTA
The abdominal aorta [aorta abdominalis] (fig. 479), the abdominal portion of the descending aorta, begins at the aortic opening in the diaphragm opposite the lower broder of the twelfth thoracic vertebra, and ends usually opposite the middle of the body of the fourth lumbar vertebra by dividing into the right and left common iliac arteries. It is at first centrally placed between the medial crura of the diaphragm, but as it descends in front of the lumbar vertebrse it leaves the middle line, and, at its bifurcation, lies a little to the left side of the spine.
The place at which the aorta bifurcates may be somewhat roughly indicated on the surface of the abdomen by a point about 2.5 cm. (1 in.) below and a little to the left of the umbilicus. The level of its bifurcation may be more accurately determined by drawing a straight line across the front of the abdomen joining the highest points of the iliac crests.
The inferior vena cava, which accompanies the abdominal aorta, lies to its right side. Below, the vein is in contact with the artery and on a somewhat posterior plane; but above, it is separated from the aorta by the right medial crus of the diaphragm, and, in consequence of the caval opening in the diaphragm being placed further forward than the opening for the aorta, is on an anterior plane.
Relations. — In front, the aorta is successively crossed from above downward by the right lobe of the liver, the cceHac (solar) plexus, the lesser omentum, the termination of the oesophagus in the stomach, the ascending layer of the transverse meso-colon, the splenic vein or commencement of the portal vein, the pancreas, the left renal vein, the third portion of the duodenum, the mesentery, the aortic plexus of the sympathetic nerve, the internal spermatic or ovarian arteries, the inferior mesenteric artery, the median lumbar lymphatic nodes and lymphatic vessels, and the small intestines.
Of these structures the cceliac (solar) plexus, the aortic plexus, the splenic vein or the commencement of the portal vein, the pancreas, the left renal vein, the duodenum, the lymphatics, the spermatic or ovarian arteries, and the peritoneal reflexions are in contact with the aorta.
Hypogastric artery
On the right side from above downward are the right medial crus of the diaphragm, the great splanchnic nerve, the caudate lobe of the liver, tlie receptaculum chyU and beginning of the thoracic duct (the two latter structures are on a posterior plane), the right coeHac (semilunar) gangUon, and the inferior vena cava.
On the left side are the left medial crus of the diaphragm, the left splanchnic nerve, and the left cocliac (semilunar) ganghon. The pancreas is also in contact with the aorta on the left side, and the small intestines are separated from it only by peritoneum.
left renal; (7) right and left internal spermatic; (8) right and left second lumbar; (9) inferior mesenteric; (10) right and left third lumbar; (11) right and left fourth lumbar; (12) right and left common iliac; (13) middle sacral.
right and left phrenics, and the four right and left lumbars.
The visceral branches supply the viscera. Three of these are given off singly from the front of the aorta, namely, the cceliac, the superior mesenteric, and the inferior mesenteric; and three are given off in pairs, namely, the two suprarenals, the two renals, and the two spermatics.
1. THE INFERIOR PHRENIC ARTERIES
The inferior phrenic artery [a. phrenica inferior] usually arises from the aorta as it passes between the medial crura of the diaphragm. At times it comes off from the cceliac artery; or when it arises as two separate vessels, either the right or left vessel may come from this artery, or from other of the upper branches of the abdominal aorta.
The right phrenic passes (fig. 480) over the right medial crus of the diaphragm behind the vena cava, and then upward and to the right between the central and right leaflets of the central tendon of the muscle, where it divides into an anterior and a posterior branch. The former courses anteriorly and medially and anastomoses with the anterior branch of the left phrenic, with the musculo-phrenio branches of the internal mammary, and with the pericardiophrenic arteries; the latter passes posteriorly and laterally toward the ribs, and anastomoses with the intercostal arteries. Besides the two terminal branches and branches for the supply of the diaphragm itself the right phrenic gives off the right superior suprarenal [ramus suprarenaUs superior], to the right suprarenal gland, as well as branches to the vena cava,- to the hver, and to the pericardium.
The left phrenic crosses the left medial crus of the diaphragm behind the CESophagus, and, like the right artery, divides into an anterior and posterior branch and gives off a left suprarenal branch. The distribution and anastamoses are similar on the two sides.
The lumbar arteries [aa. lumbales] (fig. 479), usually eight in number, four on each side, come off in pairs from the posterior aspect of the abdominal aorta, opposite the bodies of the four upper lumbar vertebrae. A fifth pair of lumbar arteries, generally of small size, frequently arises from the middle sacral artery opposite the fifth lumbar vertebra. The lumbar arteries, which are rather longer on the right than on the left side, in consequence of the aorta lying a little to the left of the median line, wind more or less transversely around the bodies of the vertebrae to the space between the transverse processes, where they give off each a dorsal branch, and then, coursing forward between the abdominal muscles, terminate, by anastomosing with the other arteries of the abdominal wall.
Relations. — As they wind around tlie bodies of the vertebra they pass beneath the chain of the sympathetic nerve trunk, and the upper two beneath the crura of the diaphragm. The right arteries also pass beneath the vena cava inferior, and the two upper on that side beneath the receptaculum chyli. The arteries on both sides then dip beneath the tendinous arch thrown across the sides of the bodies of tlie vertebrae by the psoas, and continue beneath this muscle until they arrive at the interval between the transverse processes of the vertebrae and the medial edge of the quadratus lumborum. While under cover of the psoas they are accompanied by two slender filaments of the sympathetic nerve and by the lumbar veins. A httle anterior to the transverse processes they are crossed by branches of the lumbar plexus, and here usually cross in front of the ascending lumbar vein. They now pass behind the quadratus lumborum, with the exception sometimes of the last, which ma}' pass in front of the muscle. At the lateral edge of the quadratus they run between the transversus and the internal oblique, and then, after perforating the internal oblique between the internal and external oblique. Finally, much diminished in size, they enter the rectus, and give off one or more anterior cutaneous branches, which accompany the last thoracic and the ilio-hypogastric nerves to the skin. They anastomose with the lower intercostals, ilio-lumbar, deep ckcumflex iliac, and inf. epigastric arteries.
abdomen.
(c) The dorsal branch [r. dorsahs]. This is of large size, and passes backward in company with the dorsal nerve between the transverse processes above and below, the intertransversalis medially and the quadratus lumborum laterally, to the muscles of the back. On reaching the interval between the longissimus dorsi and multifidus spinae, it divides into a lateral and a medial branch. The former ends in the multifidus, the latter and larger supphes the sacrospinalis, and gives branches which accompany the termination of the dorsal nerves to the skin. Just before the artery passes between the transverse processes it gives off a spinal branch fr. spinalis], which accompanies the lumbar nerve through the intervertebral foramen into the vertebral canal (see p. 590).
(d) Renal branches of small size pass forward in front of the quadratus lumborum to the capsule of the kidney. They anastomose with the renal artery. A communication is thus established between the renal arteries and the arteries supplying the lumbar region.
The coeliac artery [a. coeliaca] — or coeliac axis, as it is commonly called, because it breaks up simultaneously into three branches which radiate from it like the spokes of a wheel from the axle — is a short thick trunk given off from the front of the aorta between the medial crura of the diaphragm a little below the aortic opening. It passes horizontally forward above the upper margin of the pancreas for about half an inch, and then breaks up into three branches for the supply of the stomach, duodenum, spleen, pancreas, liver, and gallbladder (fig. 481).
Relations. — In front is the lesser omentum; behind, the aorta; above, the right lobe of the liver; below, the pancreas; to the right, the right coeliac (semilunar) ganghon and caudate lobe of the liver; to the left, the left cceliac (semilunar) ganglion and the cardiac end of the stomach. It is closely surrounded by the dense coeliac (solar) ple.xus of sympathetic nerves.
left toward the cardiac end of the stomach, where it turns sharply round, and then, following the lesser curvature of the stomach, descends from left to right toward the pylorus. It anastomoses with the right gastric branch of the hepatic artery, which has proceeded from the opposite direction, the two branches thus forming a continuous arterial arch corresponding to the lesser curvature of the stomach.
The artery at first lies behind the posterior layer of the omental bursa of peritoneum (fig. 480), but on reaching the cardiac end of the stomach it passes, between the layers of peritoneum reflected from the diaphragm onto the oesophagus, into the lesser omentum in which it then runs to its terminal anastomosis with the pyloric. It is surrounded by a plexus of sympathetic nerves.
The hepatic artery [a. hepatica], the largest branch of the coeliac artery in the foetus, but intermediate in the adult between the left gastric and the splenic, comes off on the right side of the coeliac artery, and, winding upward and to the right to the porta (portal fissure) of the liver, there breaks up into two chief branches for the supply of the right and left lobes of that organ. It at first courses forward and to the right along the upper border of the head of the pancreas, behind the posterior layer of the peritoneal omental bursa, to the upper margin of the duodenum, where it passes forward beneath the layer of peritoneum forming the floor of the epiploic foramen (of Winslow). It thus runs between the two layers of the lesser omentum, and ascends along with the hepatic duct which lies to its right, and with the portal vein which lies behind it (figs. 480, 481).
(1) The right gastric artery [a. gastrica dextra] comes off from the hepatic just as the latter vessel enters the lesser omentum, and, descending between the two layers of that fold of peritoneum to the pylorus, there turns to the left, and, ascending from right to left, anastomoses along the lesser curvature of the stomach, as already mentioned, with the left gastric artery, which descends from the opposite direction.
THE SPLENIC ARTERY 595
a little beyond the pyloric. It descends behind the superior portion of the duodenum to the lower border of the pylorus, where it divides into the right gastro -epiploic and the superior pancreatico-duodenal. It varies from 1.2 to 2.5 cm. (I to 1 in.) in length.
(a) The right gastro-epiploic artery [a. gastroepiploica dextra] passes from right to left along the greater curvature of the stomach between the laj;ers of the great omentum, and anastomoses with the left gastro-epiploic branch of the splenic. From this anastomotic arch are given oS: — (i) Ascending or gastric branches, which supply the anterior and posterior surfaces of the stomach, and anastomose with the descending gastric branches of the arteries along the lesser curvature, (ii) Epiploic [rami epiploici] or omental branches — long slender vessels which descend between the two anterior layers of the great omentum, and then, looping upward, anastomose with similar slender branches given off from the middle and left colic, and passing down in Uke manner between the two posterior layers of the great omentum.
(6) The superior pancreatico-duodenal [a. pancreaticoduodenaUs superior] — the smaller division of the gastro-duodenal — arises from that vessel as it passes behind the first portion of the duodenum, and courses downward behind the peritoneum, in the anterior groove between the second portion of the duodenum and the pancreas, to anastomose with the inferior pancreatico-duodenal, a branch of the superior mesenteric. Both the inferior and superior pancreatico-duodenal give off duodenal [rami duodenales] and pancreatic branches [rami pancreatici] to supply these organs.
(3) The hepatic artery proper [a. hepatica propria] is the continuation of the hepatic after the gastro-duodenal has arisen. It ascends between the layers of the lesser omentum, preserving the relations of the main artery to the portal vein and common bile (and hepatic) duct, and divides, near the porta hepatis, into right and left branches.
(a) The right branch [r. dexter], given off at the porta (portal fissure) of the liver, runs to the right either behind the hepatic and cystic ducts, or between these strucures. At the right end of the porta it divides into or more branches, which again subdivided as they enter the hver substance for the supply of the right lobe. As it crosses the cystic duct it gives off the cystic artery. The cystic artery [a. cystica] courses forward and downward through the angle formed by the union of the hepatic and cystic ducts, and just before it reaches the gall-bladder divides into a superficial and deep branch. The former breaks up into a number of small vessels, which ramify over the free surface of the gall-bladder beneath the peritoneal covering, and furnish branches to the muscular and mucous coats. The deep branch ramifies between the gallbladder and the liver^ubstance, supplying each, and anastomosing with the superficial branch.
(b) The left branch [r. sinister], the smaller division of the hepatic artery, runs medialward toward the left end of the porta hepatis, and, after giving off a distinct branch to the caudate (Spigelian) lobe, enters the left lobe of the liver.
The splenic artery [a. lienalis] — the largest branch of the cceliac artery — arises from the left side of the termination of that vessel below the left gastric, and passes along the upper border of the pancreas in a tortuous manner to the spleen. It at first lies behind the ascending layer of the transverse meso-colon, but on nearing the spleen enters the lieno-renal ligament, and there breaks up into numerous branches, which enter the hilus and supply the organ. In this course it crosses in front of the left medial crus of the diaphragm and the upper end of the left kidney and is placed above the splenic vein.
(1) The pancreatic branches (rami pancreatici) come off from the splenic at varying intervals as that vessel courses along the upper margin of the pancreas. They enter and supply the organ. One larger branch usually arises from the splenic about the junction of its middle with its left third. Entering the pancreas obUquely, it runs from left to right, commonly above, and a httle behtad, the pancreatic duct, whidh it supplies together with the substance of the organ.
(2) The left gastro-epiploic [a. gastroepiploica sinistra] arises from the splenic near the greater curvature and below the fundus of the stomach, and, passing between the anterior layers of the great omentum, descends along the greater curvature of the stomach from left to right, and anastomoses with the right gastro-epiploic. Like that vessel, it gives off ascending or gastric branches to the anterior and posterior surfaces of the stomach respectively, and long slender descending epiploic or omental branches to the great omentum which anastomose with like branches from the right and left colic arteries.
(3) The vasa brevia [aa. gastrics breves] come off from the splenic just before it divides into its terminal branches, oftentimes from some of these terminal branches themselves. Passing from between the folds of the Ueno-renal ligament into those of the gastro-henal, they thus reach the fundus of the stomach, where, ramifying over both its anterior and posterior surfaces, they anastomose with the left gastric and left gastro-epiploic arteries.
(4) The splenic or terminal branches, five to eight or more in number, are given off from the splenic as it lies in the lieno-renal ligament, and, entering the spleen at the hilum, are distributed in the way mentioned in the description of that organ.
The superior mesenteric artery [a. mesenterica superior] is given off from the front of the aorta a little below the cojliac, which it nearly equals in size; sometimes it forms a common trunk with the coehac. Lying at first behind the pancreas and splenic vein, it soon passes forward between the lower border of that gland and the upper border of the inferior portion of the duodenum, and, crossing in front of the duodenum, enters the mesentery, in which it runs from left to' right, in the form of a curve with its convexity to the left, to the caecum, where it anastomoses with its ileo-colic branch. Its vein Hes to its right side above, having
enteric artery
previously crossed obhquely in front of the artery from left to right. It is surrounded by the mesenteric plexus of nerves. The accessory portion of the head of the pancreas dips in behind the vessel.
The branches of the superior mesenteric are, in their primitive order: — (1) the inferior pancreatico-duodenal; (2) the intestinal arteries; (3) the ileocolic; (4) the right colic; and (5) the middle colic.
(1) The inferior pancreatico-duodenal [a. pancreatico duodenaUs inferior] arises either from the superior mesenteric as that vessel emerges from the contiguous margins of the pancreas and inferior part of the duodenum or from its first intestinal branch. Crossing behind the superior mesenteric vein, it courses upward and to the right between the head of the pancreas and the duodenum, and beneath the ascending layer of the transverse meso-colon, to anastomose with the superior pancreatico-duodenal.
Fig. 483. — The Blood-vessels of the Ileo-c^cal Region. (From Kelly.) (Arteries red, veins blue.) The peritoneal covering is removed so as to show the vessels more clearly. Above and to the right are seen the cut ends of the ileo-cohc artery and vein. This artery gives off a branch to the ascending colon and a posterior and anterior ctecal artery, the latter descending through the ileo-colic fold. A short anastomosis connects the ileocohc with the mesenteric. The artery of the vermiform process (appendix) is seen to arise from the posterior cfecal artery, 2 cm. above the ileum. It passes behind the ileum in the free border of the mesappendix and gives off five branches (long appendices have 8-12, short appendices, 2-3), which traverse the mesappendix at fairly regular intervals in the direction of the hilus of the appendix, where they divide into anterior and posterior branches. The branches in the me.sappendix are sometimes seen to anastomose, forming loops of varying size. The terminal branch curves around the tip. The CEeco-appendicular junction is supplied by a separate branch arising likewise from the posterior ileo-caecal trunk. This branch may or may not anastomose with the proximal appendicular twig and while in some cases it supplies only the caecum, in others, as in the present case, it sends a few dehcate branches into the appendix. At the place where this caeco-appendicular artery crosses the ileo-caecal fold it is seen to give off a dehcate recurrent twig to this structure. Throughout their entire course the arteries are accompanied by veins.
each divides into two branches, which inosculate with similar branches given oS from the branch above and below. From the primary loops thus formed, secondary loops are derived in Hke manner, and from these tertiary, and at times quaternary, or even quinary loops. From the ultimate loops terminal jejunal and iliac branches [aa. jejunales et iliea;] pass on to the muscular coat of the gut. These terminal vessels bifurcate, the two branches encircling the intestine, and thus forming with those above and below a series of vascular rings surrounding the small intestine throughout its whole length. The first intestial artery anastomoses with the pancreatico-duodenal arteries, and the last (the continuation of the main artery) with the Ueo-coUc. These branches of the superior mesenteric in their course to the intestine also supply the mesentery and the mesenteric glands.
(3) The ileo-colic [a. ileocolica] descends behind the peritoneum toward the caecum, where it divides into a cohc branch which tracks upward beneath the peritoneum to anastomose with the descending branch of the right cohc; and into an ihac branch which passes between the layers of the mesentery and anastomoses with the termination of the superior mesenteric artery. Near the site of division the ileo-colic gives off anterior and posterior csecal branches. From the latter of these arises a caeco-appendicular artery, to the caecum and root of the vermiform process, and a main appendicular artery [a. appendicularis] (fig. 483).
(4) The right colic [a. colica dextra] — sometimes given off as a common trunk either with the middle colic or with the ileo-colic — passes to the right behind the peritoneum to the back of the ascending colon, where it divides into an ascending branch, which anastomoses with the descending branch of the middle cohc, and a descending branch which anastomoses with the ascending or colic branch of the ileo-cohc.
(5) The middle colic [a. colica media], arising from the concavity of the superior mesenteric a little below the pancreas, enters the transverse meso-colon, and divides into two branches — one of which passes to the left and anastomoses with the ascending branch of the left colic; the other, winding downward and to the right, anastomoses with the ascending branch of the right colic.
THE RENAL ARTERIES
The renal arteries [aa. renales] come off one on each side of the abdominal aorta, a little below the superior mesenteric and first lumbar arteries, on a level with the first lumbar vertebra. They pass laterally across the crura of the diaphragm to the kidneys, the right being on a slightly lower plane and somewhat longer than the left, and passing behind the inferior vena cava. In front of each is the corresponding renal vein, and behind, at the hilus of the kidney, is the commencement of the ureter. Each artery as it enters the hilus usually divides into three main stems, one of which passes toward the upper part of the pelvis, a second to its middle portion, and a third to its lower. Each of these primary stems then divides so that there result from seven to nine secondary branches, the majority of which pass anterior to the pelvis, while the remainder are posterior to it (fig. 484). No anastomoses take place between the branches of the anterior and posterior secondary stems and hence a longitudinal incision into the kidney along its curved border, half way between the anterior and posterior calices, will cut only terminal arteries.
The middle suprarenal artery [a. suprarenahs media] comes off, one on each side from the aorta, just above the first lumbar artery, and passes laterally to the suprarenal body, across the medial crura of the diaphragm a little above the renal arteries. In the foetus they equal the renals in size. In the adult they are much smaller.
They anastomose with the superior and inferior suprarenal arteries from the inferior phrenic and renal arteries respectively. For the distribution of the suprarenal vessels within the suprarenal bodies, see Section XII.
THE INTERNAL SPERIVIATIC ARTERIES
The internal spermatic arteries [a. spermatica interna], (fig. 479), right and left, come off from the front of the abdominal aorta. They diverge from each other as they descend over the aorta and psoas muscle to the abdominal inguinal (internal abdominal) ring, where they are joined by the ductus deferens, and, pass-
ing with it through the inguinal canal and out of the subcutaneous inguinal (external abdominal) ring, run downward into the scrotum in a tortuous course to the testes. They terminate in branches to the epididymis and body of those organs. Within the abdomen they lie beneath the peritoneum, and cross in their descent over the ureters and distal ends of the external iliac arteries; the right being super-
FiG. 484. — A. The Renal Artery and the Distribution of its Branches in Relation TO THE Pelvis. B. Transverse Section through the Middle op the Same Kidney. (After Brodel, Johns Hopkins Hospital Bulletin.)
o, renal artery; a' and a", its anteiior and pubtenor branches, 6, branches to pyramids; c, line of division between anterior and po&tenoi pyi imids The arrow and dotted Una indicate the line of separation between tin fi lunn iK ot the anterior and posterior branches.
ficial to the vena cava, and behind the termination of the ileum; and the left beneath the sigmoid colon. In the inguinal canal and in the scrotum the spermatic veins lie in front of the artery, and the ductus deferens lies behind it.
(4) The testicular arteries [aa. testiculares] are the terminal branches of the spermatic; they perforate the tunica albuginea posteriorly, and are distributed to the body of the organ in the way mentioned in the section on the Testis.
The ovarian arteries [aa. ovaricse], are the homologues of the internal spermatic arteries in the male, and correspond in their relations in the upper part of their course. They diverge somewhat less, however, and, on reaching the level of the common iliac artery, turn medialward over that vessel and descend tortuously into the pelvis between the folds of the broad ligament to the ovaries. In the broad hgament the ovarian artery lies below the Fallopian tube, and on reaching the ovary turns backward and supplies that organ. In fig. 486 is shown how the artery enters the hilus of the ovary and breaks up into_branches which determine the lobules of the organ.
the inguinal canal, and anastomosing with the superficial external pudendal artery.
Like the spermatic, the ovarian arteries in the foetus come off at right angles to the aorta, and pass transversely lateralward to the ovaries, which are formed, as are the testes, in the right and left loin in front of the kidneys. They elongate as the ovaries descend into the pelvis. During pregnancy these arteries undergo great enlargement.
above the bifurcation of that vessel. It runs obliquely downward and to the left, behind the peritoneum, across the lower part of the abdominal aorta a,nd then over the left psoas muscle and left common iliac artery. It descends into the
THE COMMON ILIAC ARTERIES 603
pelvis between the layers of the sigmoid meso-colon, and terminates on the rectum in the superior hsemorrhoidal artery. It supplies the lower half of the large intestine. Its vein lies at first close to the left side, but soon passes upward on the psoas, away from the artery, to end in the splenic vein (fig. 487).
(1) The left colic artery [a. colica sinistra] runs transversely to the left, beneath the peritoneum, and divides into two branches, one of which, entering the transverse meso-colon, ascends upward and to the right, to anastomose with the middle colic. The other descends, and, entering the sigmoid meso-coion anastomoses with tlie ascending branch of the sigmoid artery.
(2) The sigmoid artery [a. sigmoidea] runs downward and to the left over the psoas muscle and, entering the sigmoid meso-colon, divides into two branches; the upper anastomosing with the left cohc, the lower with the superior hemorrhoidal.
(3) The superior haemorrhoidal artery [a. hasmorrhoidaUs superior] is the continued trunk of the inferior mesenteric. It descends into the pelvis, behind the rectum, between the layers of the sigmoid meso-colon. On reaching the wall of the bowel it bifurcates, one branch proceeding on either side of the gut, to within 10 or 12 cm. (4 or 5 in.) of the anus. Here each again divides, and the branches, piercing the muscular coat, descend between that coat and the mucous membrane, forming with each other, and with the middle haemorrhoidal arteries — derived from the hypogastric (internal ihac) — a series of small vessels, running longitudinally to the rectum, and parallel to each other as far as the level of the internal sphincter, where, by their anastomosis, they form a series of loops around the lower part of the rectum.
The middle sacral artery [a. sacralis media], is, anatomically, the continuation of the aorta. The coccygeal glomerulus [glomus coccygeum], in which it terminates, is believed to contain the rudiments of the caudal aorta. The artery extends from the bifurcation of the aorta to the tip of the coccyx. As it passes downward into the pelvis, it runs behind the left common iliac vein, the hypogastric plexus of the sympathetic nerve, and the peritoneum. It lies successively upon the intervertebral disc between the fourth and fifth lumbar vertebrse, the fifth lumbar vertebra, the intervertebral disc between that vertebra and the sacrum, and lower down upon the anterior surface of the sacrum and coccyx.
(1) The lowest lumbar artery [a. lumbahs ima], which, when present, usually comes off from the middle sacral artery. Each vessel of this pair runs laterally beneath the common ihac artery and vein; and, after giving off a dorsal branch, ramifies over the lateral part of the sacrum, and ends in the iliacus muscle by anastomosing with the circumflex Oiac artery. The dorsal branch passes to the back between the last lumbar vertebra and the sacrum and ramifies in the gluteus maxiraus, anastomosing with the lumbar arteries above, and the superior gluteal artery below.
(2) Lateral sacral branches, are usually four in number. They are serially homologous with the intercostal and lumbar arteries given off by the aorta. They run laterally, and anastomose with the lateral sacral branches of the hypogastric (internal iliac) artery. They give off small spinal branches, which pass through the sacral foramina, and supply the sacral canal and back of the sacrum.
(3) Rectal or haemorrhoidal branches pass forward beneath the peritoneum or in the sigmoid meso-colon to the rectum, which they help to supply, and anastomose with the other haemorrhoidal or rectal arteries.
The common iliac arteries [aa. iliacse communes] arise opposite the left side of the middle of the body of the fourth lumbar vertebra, at the bifurcation of the abdominal aorta, and, diverging from each other in the male at about an angle of 60°, and in the female at an angle of 68°, terminate opposite the lumbo-sacral articulation by bifurcating into the external iliac, which is continued along the brim of the pelvis to the lower hmb, and into the hypogastric (internal iliac), which passes through the superior aperture of the pelvis and descends into that cavity (fig. 488).
the median line.
Relations. — In front it is covered by the peritoneum, and is crossed by the right ureter a little before its bifurcation, by the ovarian artery in the female, by the termination of the ileum, by .the terminal branches of the superior mesenteric artery, and by branches of the sympathetic nerve descending to the hypogastric plexus.
Behind, it hes on the right common iliac vein, the end of the left common ihac vein, and the commencement of the inferior vena cava, which separate it from the fourth and fifth lumbar vertebrae and their intervening disc, the psoas muscle, and the sympathetic nerve; whilst still deeper in the groove between the fifth vertebra and the psoas are the lumbo-sacral trunk, the obturator nerve, and the ilio-lumbar artery.
thicker than the right.
Relations. — In front it is covered by the peritoneum, which separates it from the intestines, and is crossed by the ureter, the ovarian artery in the female, branches of the sympathetic nerve descending to the hypogastric plexus, the termination of the inferior mesenteric artery, the sigmoid colon, and the sigmoid mesocolon.
Behind are the lower border of the body of the fourth lumbar vertebra, the disc between the fourth and fifth lumbar vertebra, the body of the fifth lumbar vertebra, and the disc between it and the sacrum. Crossing deeply behind the artery between the fifth lumbar vertebra and the psoas, is the obturator nerve, the lumbo-sacral trunk, and the ilio-lumbar artery.
Collateral Circulation
The collateral circulation after obstruction or ligature of the common ihac artery is carried on chiefly (fig. 497) by the anastomosis of the middle sacral with the lateral sacral; the internal mammary with the epigastric; the lumbar arteries of the aorta with the iho-lumbar and deep circumflex iliac; the pubic branch of the epigastric with the pubic branch of the obturator; the posterior branches of the sacral arteries with the superior gluteal (gluteal) ; the superior hemorrhoidal from the inferior mesenteric, with the hfemorrhoidal branches of the hypogastric (internal iliac) and pudic; the ovarian arteries from the aorta with the uterine branches of the hypogastric (internal iliac) ; and by the anastomosis across the middle line of the pubic branch of the obturator with the like vessel of the opposite side; the lateral sacral with the opposite lateral sacral; and the vesical, hemorrhoidal, uterine, and vaginal branches of the hypogastric with the corresponding branches of the opposite hypogastric (internal iliac).
There are a few small, unimportant branches distributed to the peritoneum and subperitoneal fat. They anastomose with vessels given off from the lumbar, inferior phrenic, and renal arteries, forming a subperitoneal arterial anastomosis. The ureter receives small insignificant twigs as it crosses the artery. They anastomose with the ureteral arteries given off from the internal spermatic above, and with those derived from the vesical arteries below.
The hypogastric or internal iliac artery [a. hypogastrica], arises at the bifurcation of the common iliac opposite the lumbo-sacral articulation. It descends into the pelvis for about 3 cm. (1| in.) and then divides, opposite the upper margin of the great sciatic foramen, into an anterior and a posterior division. The anterior divisio?i commonly gives off the obturator, inferior gluteal, umbilical,
inferior vesical, deferential, middle hsemorrhoidal, uterine fin the female), and internal pudendal arteries. From the posterior division the ilio-lumbar, lateral sacral, and superior gluteal arteries arise. These vessels are classified, for description, as parietal and visceral.
In the adult the hypogastric is smaller than the external ihac; in the foetus it is much larger and through it the foetal blood is returned to the placenta. The adult hypogastric and common ihac arteries of either side represent the proximal portion of each of the embryonic umbilical arteries. The remainder of the umbUical artery within the body is represented by the umbiMcal branch of the hypogastric which runs to the navel. At birth, when the circulation in the umbihcal cord ceases, the lumen of the umbihcal branch of the hypogastric becomes obhterated except a small channel which remains pervious as the superior vesical of tlie adult.
Relations. — Behind, the hypogastric artery rests on the termination of the external iliac vein, the hypogastric vein, the medial margin of the psoas muscle, the lumbo-sacral trunk, the obturator nerve, and the sacrum.
Internal obturator muscle
The branches of the hypogastric artery may be divided into parietal and visceral sets. The parietal branches are: — -(1) The ilio-lumbar; (2) the lateral sacral; (3) the obturator; and (4) the gluteal arteries.
The ilio-lumbar artery [a. iliolumbalis] — a short vessel coming off from the posterior part of the hypogastric artery — -runs upward and laterally beneath the , common iliac artery, first between the lumbo-sacral trunk and obturator nerve,
The iliac branch [ramus iliaous] passes laterally beneath the psoas and the femoral (anterior crural) nerve and, perforating the iUacus, ramifies in the iliac fossa between that muscle and the bone. It supphes a nutrient artery to the bone, and then breaks up into several branches which radiate from the parent trunk, upward toward the sacro-iUac synchondrosis, laterally toward the crest of the Uium, downward toward the anterior superior spine, and medially toward the pelvic cavity. The first anastomoses witli the last lumbar; the second with the external circumflex and gluteal; the third with the deep circumflex iUac from the external ihac; the fourth with the Uiac branch of the obturator. The lumbar branch [ramus lumbalis] ascends beneath the psoas, and, supplying that muscle and the quadratus lumborum, anastomoses with the last lumbar artery. It sends a spinal branch (ramus spinalis) into the vertebral canal through the intervertebral foramen between the last lumbar vertebra and the sacrum; this branch anastomoses with the other spinal arteries. The Qio-lumbar artery is serially homologous with the lumbar arteries. Hence the similarity in its course and distribution.
Second perforating artery
are present, runs downward and medially to the first anterior sacral foramen, through which it passes; and, after supplying the spinal membranes and anastomosing with the other spinal arteries, passes through the first posterior sacral
foramen, and is distributed to the skin over the back of the sacrum, there anastomosing with branches of the superior and inferior gluteal arteries. The inferior lateral sacral descends on the side of the sacrum, lateral to the sacral chain of the sympathetic, and medial to the anterior sacral foramina, crossing in its course the slips of origin of the piriformis muscle and the first anterior sacral nerve. On reaching the coccyx it anastomoses in front of that bone with the middle sacral artery, and with the inferior lateral sacral of the opposite side (fig. 489).
In this course it gives off: — Spinal branches [rami spinales], which enter the second, third and fourth anterior sacral foramina, and, after supplying the spinal membranes and anastomosing with each other, leave the spinal canal by the corresponding posterior sacral foramina, and are distributed to the muscle and skin over the back of the sacrum; and rectal branches which run forward to the rectum.
At times the lateral sacral arteries are exceedingly small, the spinal branches then coming chiefly from the middle sacral. The anastomosing branches between the lateral sacral and middle sacral are usually regarded as sacral arteries diminished in size, and serially homologous with the lumbar and intercostal arteries.
• The obturator artery [a. obturatoria], usually arises from the anterior division of the hypogastric. It runs forward and downward a Httle below the brim of the pelvis, having the obturator nerve above and the obturator vein below. It here lies between the peritoneum and the endo-pelvic fascia, but later it passes through the obturator canal, the aperture in the upper part of the obturator membrane. In this course it is crossed by the ductus deferens. On emerging from the obturator canal the artery divides into two branches, anterior and posterior, which wind around the margin of the obturator foramen beneath the obturator externus muscle.
terminal branches.
(1) The iliac or nutrient branch ascends to the iliac fossa, passing between the iUacus muscle and the bone. It suppUes a nutrient vessel to the ihum, and anastomoses with the medial branch of the iliac division of the ilio-lumbar artery.
of the bladder to that organ, where they anastomose with the other vesical arteries.
(3) The pubic branch [ramus pubicus] comes off from the obturator as that vessel is leaving the pelvis by the obturator canal. It runs upward and medially behind the pubis, anastomosing with its feUow of the opposite side of the body, and with the pubic branch of the inferior epigastric artery. One of the anastomosing channels between the pubic branch of the obturator and pubic branch of the inferior epigastric arteries is sometimes of large size, a fact of surgical interest in that the enlarged vessel may then run around the medial side of the femoral ring (pp. 615 and 636).
(4) The anterior branch [ramus anterior] runs around the medial margin of the obturator foramen, and anastomoses with the posterior branch and with the medial circumflex artery. It supplies branches to the obturator and adductor muscles.
(5) The posterior branch [ramus posterior] skirts the lateral margin of the obturator foramen, lying between the obturator externus and the obturator membrane. At the lower margin of the foramen it divides into two branches. One branch continues its course around the lower margin of the foramen, and anastomoses with the anterior branch of the obturator and with the medial circumflex. The other branch turns laterally below the acetabulum, and ends in the muscles arising from the tuberosity of the ischium. It anastomoses with the inferior gluteal artery. This branch gives off a small twig, the acetabular artery [a. acetabuli], which passes under the transverse Ugament into the hip-joint, where it suppUes the synovial membrane, the hgamentum teres, and the fat in the fossa at the bottom of the acetabulum.
There are two gluteal arteries, the superior and inferior. The superior
gluteal artery [a. glutea superior], the largest branch of the posterior division of the hypogastric comes off as a short, thick trunk from the lateral and back part of that vessel, of which indeed it may be regarded as the continuation. Passing backward between the first sacral nerve and the lumbo-sacral trunk through an osseo-tendinous arch formed by the margin of the bone and the upper edge of the endo-pelvic fascia, it leaves the pelvis through the great sciatic foramen above the piriformis muscle in company with its vein and the superior gluteal nerve. At its exit posteriorly from the great sciatic foramen it lies under cover of the gluteus
THE INFERIOR VESICAL ARTERY 609
maximus and beneath the superior gluteal vein, and in front of the superior gluteal nerve. It here breaks up into two chief branches, a superficial and a deep. Its emergence from the pelvis is indicated on the surface by a point situated at the junction of the posterior with the middle third of a line drawn from the anterior superior to the posterior superior spine of the ilium.
(i) The superior branch [ramus superior] breaks up into a number of large vessels for the supply of the upper portion of the gluteus maximus, some of them piercing the muscle and supplying the skin over it, and anastomosing with the posterior branches of the lateral sacral arteries; whilst one of larger size, emerging from the muscle near the ihao crest, anastomoses with the deep circumflex iliac artery. The lower branches to the muscle anastomose with branches of the inferior gluteal (sciatic).
(ii) The inferior branch [ramus inferior] subdivides into two branches — One skirts along the lane of origin of the gluteus minimus (fig. 490), between the gluteus medius and the bone, and, emerging in front from beneath these muscles under cover of the tensor fascite lata:, anastomoses with the ascending branch of the lateral circumflex and the deep circumflex iliac arteries. The other passes forward between the gluteus medius and minimus, accompanied by the branch to the tensor fasciae lata; of the inferior division of the superior gluteal nerve, toward the greater trochanter, where it anastomoses with the ascending branch of the lateral circumflex. It supphes branches to the contiguous muscles and to the hip-joint. The inferior branch before its division gives off the external nutrient artery of the ilium.
The inferior gluteal [a. glutea inferior], is one of the terminal branches of the anterior division of the hypogastric artery. It leaves the pelvis below the piriformis muscle, and immediately breaks up into a number of diverging branches. The largest enter the gluteus maximus muscle, where they anastomose with the superior gluteal branches. Others pass to the hip-joint and the deep muscles around it; a third group passes downward to the hamstring muscles and anastomoses with the medial and lateral circumflex and first perforating; a fourth slender branch, the sciatic artery [a. comitans n. ischiadici], accompanies the sciatic nerve (fig. 490).
The umbilical artery in the fcetus is the continuation of the hypogastric. Passing forward along the side of the pelvis, it runs beneath the lateral reflexion of peritoneum from the bladder, where, after giving off one or more vesical branches, it ceases to be pervious and passes on to the side and upper part of the bladder. Thence it ascends in the lateral umbilical fold, as a fibrous cord [ligamentum umbilicale laterale], to the umbilicus, where it is joined by its fellow of the opposite side. As it lies lateral to the bladder it is crossed by the ductus deferens.
The superior vesical arteries [aa. vesicales superiores] ramify over the upper surface of the bladder, anastomosing with the artery of the opposite side and with the middle and inferior vesical below. They give off the following branches: — (a) The urachal branches which pass upward along the urachus. (h) The ureteric branches pass to the lower end of the ureter, and anastomose with the other ureteric arteries, (c) The middle vesical may come off from one of the superior vesicals or from the umbilical. It is distributed to the sides and base of the bladder, and anastomoses with the other vesical arteries.
The inferior vesical artery [a. vesicahs inferior] arises from the anterior division of the hypogastric, frequently in common with the middle haemorrhoidal, and passes downward and medially to the fundus of the bladder, where it breaks up into branches which ramify over the lower part of the viscus. It gives off branches to the prostate, which supply that organ and anastomose with the arteries of the opposite side by means of descending arteries which pass through
the prostatic plexus of veins, but outside the capsule of the prostate, and with the inferior hsemorrhoidal branches of the internal pudic. At times one of these prostatic branches is of large size, and supplies certain of the parts normally supplied by the int. pudendal. It is then known as the accessory pudendal and most commonly terminates as the dorsal artery of the penis.
The inferior vesical usually gives off the deferential, or artery of the ductus deferens [a. deferentialis]. This vessel, which may come off from the superior vesical, divides, on the ductus deferens, into an ascending and a descending branch. The ascending branch follows the ductus through the inguinal canal to the testis, where it anastomoses with the internal spermatic artery. The_ descending branch passes downward to the dilated portion of the ductus and vesiculse seminales.
3. THE MIDDLE HEMORRHOIDAL ARTERY
The middle hsemorrhoidal artery [a. hsemorrhoidals media], variable in origin, perhaps most commonly arises from the anterior division of the hypogastric along with the inferior vesical. It runs medially to the side of the middle portion of the rectum, dividing into branches which anastomose above with the superior hsemorrhoidal derived from the inferior mesenteric, and below with the inferior hsemorrhoidal derived from branches of the internal pudendal. Its corresponding vein terminates in the inferior mesenteric vein. In the female it also sends branches to the vagina.
The uterine artery [a. uterina], arises from the anterior division of the hypogastric close to or in conj unction with the middle hsemorrhoidal or inferior vesical. It runs downward and medially through the pelvic connective tissue, crossing the ureter about 12 mm. (| in.) from the cervix uteri. It then turns upward and ascends in the parametrium between the layers of the broad ligament at the side of the uterus in a coiled and tortuous manner, and, after giving off a number of tortuous branches which ramify horizontally over the front and back of the uterus, supplying its substance, anastomoses with the uterine branch of the ovarian artery.
In addition to the branches to the uterus the branches of the uterine artery are: — (1) Cervical. — This branch comes off from the uterine as the latter artery crosses the ureter to turn upward on to the uterus. It is directed medially, and divides into three or four branches which pass on to the cervix at right angles to it; one branch anastomosing with its fellow of the opposite side in front and behind the neck, forming the so-caUed coronary artery of the cervix. (2) Tubal [ramus tubarius]. — Tliis courses along the lower surface of the tuba uterina (FaUopian tube) as far as its fimbriated extremity, and may also send a brancli to the ligamentum teres. (3) Ovarian [ramus ovarii]. — This runs along the attached border of the ovary, sending branches to that structure, and terminates by anastomosing widely with the ovarian artery. Usually the vaginal artery also arises from tlie uterine. (4) The vaginal artery [a. vaginaUs] corresponds to the inferior vesical artery of the male, and may arise directly from the hypogastric artery, close to the origin of the uterine, or from the superior vesical. It passes medially, behind the ureter, to the upper part of the vagina, and sends numerous branches to that structure and also some iio the posterior part of the fundus of the bladder.
The branches to the vagina tend to anastomose with one another and with the cervical branch of the uterine, to form a more or less perfect vertical stem in the median Une of the vagina, both back and front. This stem is sometimes termed the azygos artery of the vagina. Branches also pass to the vagina from the middle hsemorrhoidal artery.
The internal pudendal (pudic) artery [a. pudenda interna] (figs. 492, 493, 494) is one of the terminal branches of the anterior division of the hypogastric artery (the inferior gluteal being the other) . It arises opposite the piriformis muscle and accompanies the inferior gluteal downward to the lower border of the great sciatic foramen. It leaves the pelvis between the piriformis and coccygeus and winds over the ischial spine to enter the ischio-rectal fossa through the small sciatic foramen. Running forward in the ischio-rectal fossa medial to the lower part of the obturator internus it ends by dividing into the perineal artery and the artery of the penis (or clitoris).
Relations. — Within the -pelvis, the artery is anterior to the piriformis muscle and the sacral plexus of nerves, and lateral to the inferior gluteal artery. It passes between the piriformis and coccygeus, with the gluteal artery and pudendal nerve medial to it, and the nerve to the obturator internus lateral. The sciatic and posterior femoral cutaneous (lesser sciatic) nerves are still more lateral. On, the ischial spine the artery retains its relations to the pudendal nerve (which often divides in this situation into its two terminal branches) and the nerve to the obturator internus. It is accompanied by venae comitantes and covered by the gluteus maximus
muscle. In the ischio-rectal fossa the artery is placed on the lateral wall about 3.5 cm. (IJ in.) above the tuberosity of the ischium. It is accompanied in a canal in the obtm-ator fascia (Alcock's canal) by the dorsal nerve of the penis and the perineal nerve, which are respectively above and below the artery.
The branches of the internal pudendal artery are: — (1) Small branches to the gluteal region; (2) the inferior hsemorrhoidal arteries; and the terminal branches (3) perineal; and (4) artery to the penis or clitoris.
(1) The branches of the gluteal region are: (a) twigs to the gluteus maximus; (6) branches accompanying the nerve to the obturator internus; (c) a sacral branch which pierces the sacrotuberous ligament, and anastomoses with the inferior gluteal artery.
(2) The inferior hemorrhoidal artery (a. haemorrhoidalis inferior] (figs, 493, 494) arises at the posterior part of the ischio-rectal fossa and, perforating the obturator fascia, at once breaks up into several branches. These, rumiing medially toward the anus, traverse the ischio-rectal fat and supply the fascia, skin and the levator ani and external sphincter muscles. The inferior hEemorrhoidal branches anastomose with those from the middle and superior hemorrhoidal, and from the gluteal and perineal arteries.
(3) The perineal artery [a. perinei] (figs. 493, 494), one of the terminal arieries of the internal pudendal, arises at the anterior part of the ischio-rectal fossa. It pierces the base of the urogenital diaphragm (triangular hgament) anterior or posterior to the superficial transverse perineal muscle, and enters the space deep to CoUes's fascia. Here it runs forward between the ischio- and bulbo-cavernosus muscles to the scrotum or labium majus and divides into numerous terminal branches. Immediately after piercing the diaphragm, the perineal artery gives off a constant transverse perineal branch which runs toward the median Une along the superficial transverse perineal muscle. The terminal branches of the perineal are the posterior scrotal or labial arteries [aa. scrotales, or labiales posteriores] which ramify on the scrotum or labia majora (according to sex) and anastomose with external pudendal arteries.
On the right side CoUes's fascia has been turned back to show the perineal artery. On the left side the perineal vessels have been cut away with the inferior layer of the urogenital diaphragm to show the artery of the penis.
(a) The artery of the bulb [a. bullii urethras or vestibuli vaginas] takes a medial direction through the fibres of the m. transversus perinei profundus. It then pierces the inferior fascia of the urogenital diaphragm to reach the bulb, the erectile tissue of which it supplies, in either sex. This vessel also suppUes branches to the bulbo-urethral gland (Cowperi) or the gland of the vestibule (Bartholini).
The situation of the artery to the bulb should be remembered in performing the operation of lateral lithotomy, particularly as it may arise far back. When the artery arises, as it occasionally does, from the accessory pudendal it pierces the urogenital diaphragm further forward and is out of danger in the ordinary low operation.
The dorsal nerve is
lateral to the artery and both join the dorsal vein (which hes between the arteries of either side) on the dorsum of the penis or clitoris. The artei-y is much larger in the male than the female; in either sex it supphes the glans, corona, and prepuce and anastomoses with the external pudendal artery.
The external iliac artery [a. iliaca externa] — the larger in the adult of the two vessels into which the common iliac divides opposite the lumbo-sacral articulation — extends along the superior aperture of the pelvis, lying upon the medial border of the psoas muscle, to the lower margin of the inguinal ligament, where, midway between the anterior superior spine of the ilium and the symphysis pubis, it passes into the thigh, and takes the name of the femoral.
It measures 8.5 to 10 cm. (3| to 4 in.) in length. The course of the vessel is indicated by a line drawn from 2.5 cm. (1 in.) below and a little to the left of the umbilicus to a spot midway between the symphysis pubis and the anterior superior spine of the ilium. If this line is divided into thirds, the lower two-thirds indicate the situation of the external iliac, the upper third the common iliac. The external iliac vein, the continuation upward of the femoral vein from the thigh, lies to the medial side of the artery, but on a slightly lower plane, and, just before its termination, gets a little behind the artery on the right side.
Relations. — In front, the artery together with the vein is covered by the parietal peritoneum descending from the abdomen into the pelvis, and by a layer of condensed subperitoneal tissue (Abernethy's fascia). It is crossed by the termination of the ileum on the right side, and by the sigmoid colon on the left. The external spermatic (genital) branch of the genitofemoral (genito-crural) nerve runs obhquely over its lower third, and just before its termination it is crossed transversely by the deep circumflex iliac vein. The internal spermatic or ovarian vessels lie for a short distance on the lower part of the artery, and the ductus deferens in the male curves over it to descend to the pelvis. It is sometimes crossed at its origin by the ureter. The external iliac lymphatic nodes lie along the course of the artery. The commencement of its inferior epigastric branch is also in front.
Behind. — At first the artery lies partly upon its own vein; lower down upon the medial border of the psoas; and just before it passes through the lacuna vasorum, beneath Poupart's ligament, upon the tendon of the psoas. The continuation of the ihac into the endo-pelvic fascia is also below it.
To its lateral side is the psoas muscle and the iliac fascia.
The collateral circulation is carried on (fig. 497) when the external ihac is tied, by the anastomosis of the iUo-lumbar and lumbar arteries with the circumflex ihac; the internal mammary with the inferior epigastric; the obturator with the medial circumflex; the inferior gluteal with the medial circumflex and superior perforating; the gluteal with the lateral circumflex; the arteria comitans nervi ischiadici from the inferior gluteal, with the perforating branches of the profunda; the external pudenal with the internal pudendal; the pubic branch of the obturator with the pubic branch of the epigastric.
The branches of the external iliac artery are: — (1) The inferior epigastric; (2) the deep circumflex iliac; and (3) several small and insignificant twigs to the neighbouring psoas muscles and lymphatic gland.
The inferior or deep epigastric artery [a. epigastrica inferior] (fig. 495) usually comes off from the external iliac just above the inguinal (Poupart's) ligament. Immediately after its origin, the ductus deferens in the male, and the round ligament in the female, loop around it on their way to the pelvis. It here lies medial to the abdominal inguinal (internal abdominal) ring, behind the inguinal canal, and a little above and lateral tc the femoral ring. Thence it ascends with a slightly medial direction passing above and to the lateral side of the subcutaneous inguinal (external abdominal) ring, lying between the fascia transversalis and the peritoneum. Having pierced the fascia transversalis at this point, it
passes in front of the linea semicircularis (Douglas' fold) and turns upward between the rectus and its sheath. Higher, it enters the substance of the muscle, and anastomoses with the superior epigastric, descending in the rectus from the internal mammary.
The situation of the artery between the two inguinal rings should be borne in mind in the operation for strangulated inguinal hernia, and its near proximity to the upper and lateral side of the femoral ring should not be forgotten in the operation for femoral hernia. The arter3r is accompanied by two veins which end in a single trunk before opening into the external iliac vein.
The branches of the inferior epigastric are small and include: — (a) The external spermatic [a. spermatica externa], which runs with the ductus through the inguinal canal, supplies the cremaster muscle, and anastomoses with the internal spermatic, external pudendal, and perineal arteries. In the female a corresponding artery [a. hg. teretis uteri] accompanies the round liga-
ment of the uterus through the inguinal canal and anastomoses in a similar manner. (6) The pubic [ramus pubicus], which passes below, or sometimes above, the femoral ring to the back of the pubis, where it anastomoses with the pubic branch of the obturator. This branch, though usually small, is occasionally considerably enlarged, when its exact course becomes of great interest to the surgeon. Thus it may descend immediatelj' medial to the vein, and therefore lateral to the femoral ring, or it may course medially in front of the femoral ring and turn downward either behind the os pubis or immediately behind the free edge of the lacunar (Gimbernat's) ligament, in which situation it would be exposed to injury in the operation for the relief of a strangulated femoral hernia. In such cases the obturator may lose its connection with the hypogastric and actually arise from the inferior epigastric. Very rarely the inferior epigastric loses its connection with the external iUac and arises from the obturator. This abnormal origin of the obturator is said to occur once in every three subjects and a half; but the abnormal
artery only courses around the medial side of the ring — in which situation it is liable to injury in the operation for femoral hernia — in exceptional cases. According to Langton (Holden's 'Anatomy'), the chances are about seventy to one against this occurring. But even when it takes the abnormal course, it lies 3 mm. or so from the margin of the ring, and will probably escape injury in the division of the stricture if several short notches are made in place of a single and longer incision.
The deep circumflex iliac artery [a. circumflexa ilium profunda], arises from the lateral side of the external iliac artery either opposite the epigastric or a little below the origin of that vessel. It courses laterally just above the lower margin of Poupart's ligament, lying between the fascia transversahs and the peritoneum, or at times in a fibrous canal formed by the union of the fascia transversahs with the iliac fascia. Near the anterior superior spine of the ihum, it perforates the transversus, and then courses between that muscle and the internal oblique, along and a little above the crest of the ilium. It finally gives off an ascending branch, which anastomoses with the lumbar and lower intercostal arteries,, and runs backward to anastomose with the ilio-lumbar artery. It is accompanied by two veins. These unite into one trunk, which then crosses the external iliac artery to join the external iliac vein.
The branches of the deep circumflex iliac artery are as follows: — (a) Muscular branches which supply the psoas, iliacus, sartorius, tensor fasciae latse, and the oblique and transverse muscles of the abdomen. One of these branches, larger than the rest, usually arises about 2.5 cm. (1 in.) behind the anterior superior spine of the ilium and ascends perpendicularly between the transversus muscle and the internal oblique. It has received no name but is important to the surgeon, as it indicates the intermuscular plane between the two muscles. (6) Cutaneous branches, which supply the skin over the course of the vessel, and anastomose with the superficial circumflex ihac, the superior gluteal, and the ascending branch of the lateral circumflex.
The femoral artery (fig. 496) is the continuation of the external iliac, and extends from the lower border of Poupart's ligament, down the anterior and medial aspect of the thigh, to the tendinous opening in the adductor magnus, through which it passes into the popliteal space, and is then known as the popliteal. The femoral artery is at first quite superficial, being merely covered by the skin, and superficial and deep fascia; but, after thus passing abo.ut 13 cm. (5 in.) downward through the space known as the femoral trigone (Scarpa's triangle), it sinks at the apex of that triangle beneath the sartorius muscle, and thence to its termination continues beneath the sartorius, coursing deeply between the vastus medialis and adductor muscles in the space known as the adductor (Hunter's) canal. It at first rests upon the brim of the pelvis and head of the thigh bone, from which it is merely separated by the capsule of the hip-joint and the tendon of the psoas. Here it can be readily compressed. Owing to the obliquity of the neck of the femin- and the direct course taken by the artery, it lies lower down on muscles only, at some little distance from the bone. At its termination, in consequence of the shaft of the femur inclining toward the middle line of the body, the artery lies close to the bone, but to the mechal side. The course of the vessel when the thigh is slightly flexed and abducted — the position in which the Hmb is placed when the vessel is hgatured — is indicated by a line drawn from a spot midway between the anterior superior spine of the ilium and the symphysis pubis to the adductor tubercle. When the thigh is in the extended position and parallel to its fellow, the course of the artery will correspond to a hne drawn from the spot above mentioned to the medial border of the patella.
About 4-5 cm. (li-2 in.) below the inguinal ligament the femoral artery gives off a large branch called the profunda femoris. The portion of the artery proximal to the origin of the profunda is sometimes called the common femoral, and the continuation of the vessel the superficial femoral.
The superficial femoral varies in length according to the distance that the profunda is given off from the common femoral below Poupart's ligament. As a rule, it measures 9 cm. (Ss in.), the common 4 cm. (IJ in.). But the profunda may come off 5 cm. (2 in.) or more below Poupart's ligament, in which case the superficial femoral will be shorter to this extent; or it may
come off less than 3.7 cm. (IJ in.) below Poupart's Ugament, or even from the external ibac above Poupart's ligament, when the superficial will be longer than normal. The practical point to remember is that it is more usual to meet with a short than with a long common femoral and that if the superficial femoral is tied at the apex of the femoral trigone— i. e., the spot where the sartorius comes into contact with the adductor longus— there is nearly always a sufficient
as this point is concerned, a successful result.
The relations of the femoral artery in the femoral trigone.— In front, the femoral artery (fig. 496) is covered by the skin, the superficial fascia, the iUac portion of the fascia lata, and the lumbo-inguinal (crural) branch of the genito-femoral nerve. The superficial cu-cumflex ihao vein, and sometimes the superficial epigastric vem, descend over the artery from the medial to
the lateral side. Just above the sartorius, the artery is crossed by the most medial of the anterior cutaneous branches of the femoral nerve. The fascia transversahs, which is continued downward into the thigh beneath the inguinal ligament, is also in anterior relation, but it soons becomes indistinguishable from the sheath of the vessel.
Behind, the artery rests from above upon the tendon of the psoas muscle, which separates it from the brim of the pelvis and capsule of the hip-joint; the pectineus, and adductor longus. The artery is partially separated from the pectineus by the femoral vein and the profunda vein and artery, and from the adductor longus by the femoral vein which is almost directly behind the artery near the apex of the femoral trigone. The small nerve to the pectineus crosses behind the artery to reach its medial side.
A similar prolongation to that derived from the fascia transversaUs in front, descends behind the vessel from the iliac fascia; but this, lil^e the anterior prolongation or fascia, soon blends with the sheath of the vessels.
what behind the artery.
To the lateral side. — Above, the common stem of the femoral (anterior crural) nerve ia about 1 cm. (J in.) lateral to the artery. When the femoral nerve gives off its branches, the saphenous nerve and the nerve to the vastus mediaUs accompany the artery on the lateral side.
The adductor canal is the somewhat triangularly shaped space bounded by the vastus medialis on the lateral side, the adductors longus and magnus posteriorly, and by an aponeurosis thrown across from the adductors to the vastus medially and in front. Below, the canal terminates at the tendinous opening in the adductor magnus; above, its Umit is less well defined, as here the aponeurosis between the muscles becomes less tendinous, and gradually fades away into the perimuscular fascia. The transverse direction of the fibres of the aponeurotic covering at the lower two-thirds of the canal is characteristic, and serves as a raUying-point in tying the artery in this part of its course. Lying superficial to the aponeurosis is the sartorius muscle. The femoral artery, in the adductor (Hunter's) canal, has the following relations :■ —
In front, in addition to the skin, superficial and deep fascia, are the sartorius muscle and the aponeurotic fibres of the canal. The saphenous nerve crosses in front of the artery from the lateral to the medial side, lying in the wall of the canal.
the adductor magnus, usually with the latter muscle.
The femoral vein lies behind the artery, but gets a httle lateral to it at the lower part of the canal. It is here very firmly and closely attached to the artery, embracing it as it were on its posterior and lateral aspect. Hence it is very hable to be punctured on ligaturing the artery in this part of its course. Such an accident is best avoided by opening the sheath of the vessels well to the medial side of the front of the artery, and by keeping the point of the aneurysm needle closely applied to the vessel in passing it between the vein and the artery. There are sometimes two veins, which then more or less surround the artery.
(1) The superficial epigastric; (2) the superficial circumflex iUac; (3) the external pudendal; (4) the inguinal; (5) the profunda; (6) muscular branches; and (7) the suprema genu (anastomotica magna).
(1) the superficial epigastric artery [a. epigastrica superficialis], comes_ off from the femoral about 1.2 cm. (| in.) below the inguinal ligament. At its origin it is beneath the fascia lata, but almost at once passes through this fascia, or else through the fossa ovalis, and courses in an upward and slightly medial direction in front of the external oblique muscle almost as far as the umbilicus.
It ends in numerous small twigs, which anastomose with the cutaneous branches from the inferior epigastric and internal mammary. In its course it gives off small branches to the inguinal glands and to the sldn and superficial f ascifs. Running with it is the superficial epigastric irein, which ends in the great saphenous just before the latter passes through the fossa ovalis (saphenous opening).
(2) The superficial circumflex iliac artery [a. circumflexa ilium superficialis], (fig. 496), usually smaller than the superficial epigastric, arises either in common with that vessel, or else as a separate branch from the femoral. It passes laterally over the ihacus, and, soon perforating the fascia lata a Httle to the lateral side of the fossa ovalis, runs more or less parallel to the inguinal ligament about as far as the crest of the ihum, where it ends in branches which anastomose with the deep circumflex iliac artery.
In its course it gives off branches to the iliacus and sartorius muscles, to the inguinal glands, and to the fascia and skin. Its companion vein ends in the great saphenous vein just before the latter passes through the fossa ovaUs (saphenous opening).
Arcuate artery
through the fascia covering the fossa ovalis (saphenous opening) and cross the spermatic cord in the malCj or round ligament in the female, to reach and supply the integument above the pubes. In the female, this branch terminates in the preputium clitoridis, anastomosing with the dorsal artery of the clitoris.
Other branches run medially beneath the deep fascia, across the pectineus and adductor longus muscles, and, perforating the fascia close to the ramus of the pubis, supply the skin of the scrotum or the labium majus, in the female [aa. scrotales or labiales anteriores] anastomosing with the posterior scrotal or labial branches of the perineal artery. The external pudendal supplies small twigs to the pectineus and adductor muscles. Its companion veins terminate as a single trunk in the great saphenous.
(4) The inguinal branches [rami inguinales], a series of five or six small branches arise a short distance below the inguinal Hgament. They supply the subinguinal lymph-nodes, and the skin and muscles in this region.
(5) The profunda artery [a. profunda femoris] (figs. 496, 497), is the chief nutrient vessel of the thigh. It is usually given off from the back and lateral part of the common femoral, about 4 cm. (1| in.) below the inguinal fPoupart's) ligament. At first it is a little lateral to the femoral, but as it runs downward and backward it gets behind that artery and closer to the bone. On reaching the upper border of the adductor longus muscle, it leaves the femoral, and, passing beneath the muscle, pierces the adductor magnus. Finally, much reduced in size, it ends in the hamstraing muscles, anastomosing with the third perforating and muscular and articular branches of the popliteal.
Jlelations. — Behind, the artery Hes successively upon the iKacus, the pectineus, the adductor brevis, and adductor magnus muscles. In front, at first it is superficial, being merely covered by the skin, superficial and deep fascise, and branches of the femoral (anterior crural) nerve; but as it sinks behind the femoral artery, it has in front of it both the femoral and the profunda veins and lower down the adductor longus muscle. Laterally is the femur at the angle of union of the adductors longus and brevis. Medially is the pectineus at the upper part of its course.
Branches of the profunda. — The profunda gives off the following branches: — (a) The lateral circumflex; (h) the medial circumflex; and (c) the three perforating. The termination of the artery is sometimes called the fourth perforating branch.
(a) The lateral- circumflex [a circumflexa femoris laterahs] a short trunk, but the largest in diameter of the branches of the artery, arises from the lateral side of the profunda as it hes on the iUacus muscle, about 2 cm. (f in.) below the origin of that vessel from the femoral. It passes in a transversely lateral direction over the iliacus, under the sartorius and rectus, and between the branches of the femoral (anterior crural) nerve. In this course it gives off branches to the rectus and vastus intermedins (crureus), and then divides into two chief sets of branches — ascending and descending.
The ascending branch [ramus ascendeus] either breaks up at once into numerous branches or it may arise as several vessels some of which are apt to come from the profunda itself or even from the femoral. These run upward under the sartorius and tensor facise latse or laterally under the rectus femoris. The highest branches reach the gluteus medius and minimus and anastomose with the gluteal and deep circumflex ihac arteries; one branch runs beneath the rectus femoris to the hip-joint, and the others cross the vastus intermedins and pierce the vastus lateralis to anastomose with the first perforating and the medial circumflex.
The descending branches [rami descendentes] run directly downward along with the nerve to the vastus laterahs muscle. They lie beneath the rectus muscle and on the vastus intermedins (crureus) or vastus laterahs, some of them being j ust under cover of the anterior edge of the latter muscle. They are distributed to the vastus lateralis, vastus intermedins, and rectus, one branch usually running along the anterior border of the vastus laterahs as far as the knee-joint, where it anastomoses with the superior lateral articular branch of the pophteal (fig. 499); another, entering the vastus intermedius, anastomoses with the termination of the profunda and with the genu suprema (anastomotica magna).
(6) The medial circumflex artery [a. circumflexa femoris medialis] comes off from the back and medial aspect of the profunda artery on about the same level as the lateral circumflex; sometimes as a common trunk with that vessel. As it winds around the medial side of the femur to reach the region of the trochanters, it lies successively, flrst, between the psoas and pectineus, then between the obturator externus and adductor brevis; finaUy, between the adductor magnus and quadratus femoris, where it anastomoses with the lateral circumflex, with the inferior gluteal (sciatic), and with the superior perforating, forming the so-called crucial anastomosis. While still in the femoral trgione it gives off a superficial branch [r. superfioialis] which runs in a transversely medial direction to supply the pectineus adductor longus and brevis, and the gracilis. The remainder of the artery is designated as the deep branch [r. profundus]. An acetabular branch (r. acetabuli] courses upward beneath the tendon of the psoas, and enters the hip-joint beneath the transverse ligament, and, together with the articular branch of the obturator, supplies the fatty tissue in the acetabulum, and sends branches to the synovial membrane. The medial circumflex veins join the profunda vein.
THE POPLITEAL ARTERY 621
of loops by anastomosing with one another (fig. 497), and with the superior gluteal, medial circumflex, and inferior gluteal arteries above, and with the muscular and articular branches of the popliteal below. They are distributed chiefly to the hamstring muscles, but send twigs along the lateral intermuscular septum to supply the integuments at the back and lateral parts of the thigh. Other branches perforate the lateral intermuscular septum and the short head of the biceps, and, entering the vastus intermedins (crureus) and vastus laterahs, anastomose with the descending' branch of the lateral circumflex. All the perforating arteries, moreover, contribute to reinforce the artery of the sciatic nerve, a branch of the inferior gluteal (sciatic) artery. They are each accompanied by two veins which terminate in the profunda.
The first perforating artery [a. perforans prima] is given off from the profunda as that vessel sinks beneath the adductor longus. It either pierces the adductor brevis, or else runs between the pectineus and adductor brevis, and then passes through a small aponeurotic opening in the adductor magnus close to the medial lip of the hnea aspera. In this course it supphes branches to the adductors, and, after perforating the adductor magnus, is distributed to the lower part of the gluteus maximus and the hamstring muscles, one branch commonly running upward beneath the gluteus maximus to anastomose with the lateral circumflex, medial circumflex, and inferior gluteal (sciatic) arteries, forming the crucial anastomosis at the junction of the neck of the femur with the great trochanter (flg. 497). A second branch descends to anastomose with the ascending branch of the second perforating.
The second perforating artery [a. perforans secunda] which is given off from the profunda as it lies behind the adductor longus, pierces the adductor brevis, and then passes through a second aponeurotic opening in the adductor magnus a httle below that for the first perforating artery, and also close to the linea aspera. It supplies the hamstring muscles, sends a branch upward to anastomose with the descending branch of the first perforating, and another downward to anastomose in hke manner with the ascending branch of the third perforating.
The third perforating artery [a. perforans tertia] also arises from the profunda as it hes under the adductor longus, usually about the level of the lower border of the adductor brevis. It turns beneath this border, and then, like the first and second perforating, passes through an aponeurotic opening in the adductor magnus close to the linea aspera. It also supplies the hamstring muscles, and divides into two branches, which anastomose above with the second perforating, and below with the termination of the profunda.
(7) The genu suprema (or anastomotica magna) arises from the front and medial side of the femoral just before the latter perforates the adductor magnus muscle, and almost immediately divides into branches, (a) saphenous, {h) muscular, and (c) articular. These branches may sometimes come off separately from the femoral.
(a) The saphenous branch [a. saphena] pierces the aponeurotic covering of the adductor canal, passes between the sartorius and gracilis muscles along with the saphenous nerve, and, perforating the deep fascia, suppUes the skin of the upper and medial side of the leg and anastomoses with the inferior medial articular branch of the popUteal and the other vessels forming the plexus or rete at the medial side of the knee. In its course it gives twigs to the lower part of the sartorius and gracihs muscles.
(6) The muscular branches [rr. musculares] run downward in front of the adductor magnus tendon, burrowing amongst the fibres of the vastus mediahs as far as the medial condyle. They break up into numerous twigs which supply the lower ends of the vasti muscles and adductor magnus. One branch runs laterally across the lower end of the femur to end in the vastus laterahs.
(c) The articular branches [rr. articulares] come off from the saphenous and muscular branches and enter the arterial rete on the medial and lateral sides of the knee. They anastamose with the medial and lateral superior articular branches of the popHteal and the anterior tibial recurrent and, Uke other vessels of the rete, supply branches to the joint.
The popliteal artery [a. poplitea] (fig. 498) runs through the pophteal space or ham. It is a continuation of the femoral, and extends from the aponeurotic opening in the adductor magnus at the junction of the middle with the lower third of the thigh to the lower border of the popliteus muscle, where it terminates by dividing into the anterior and posterior tibial arteries. This division is on a level with the lower border of the tuberosity of the tibia. As the artery passes through the opening in the adductor magnus, it is accompanied by the pophteal vein, and at times by the branch of the obturator nerve to the knee-joint. The vein throughout is behind the artery, at first lying a little lateral to it, but as the vessels pass through the popliteal space the vein crosses obliquely over the artery.
and at the termination of the artery lies a little to its medial side. The tibial (internal popliteal) nerve is superficial to both artery and vein. As it enters the space it is well to the lateral side of the vessels, but as it descends it gradually approaches them, crosses behind them, and at the lower part of the space lies to their medial side. The artery in the whole of its course is deeply placed and covered by a considerable amount of fat and cellular tissue.
Relations (fig. 498). — In front, the artery lies successively on the pophteal surface of the femur (from which it is separated by a httle fat and sometimes one or two small glands); on the posterior ligament of the knee; on the hinder edge of the articular surface of the head of the tibia; and on the pophteus muscle. From the latter muscle it is separated by the expansion from the semi-membranosus which covers the muscle, and is attached to the popUteal line on the tibia.
Eopliteal vein is behind it in the whole of its course. The tibial (internal popliteal) nerve crosses ehind it obUquely, from the lateral to the medial side, about the centre of the space. As the artery divides into the anterior and posterior tibial, it is crossed by the aponeurotic arch of the soleus which stretches between the tibial and fibular origins of that muscle.
(1) The sural arteries [aa. surales] arise irregularly from the popliteal and supply the muscles of the calf, sending branches upward to the muscles bounding the upper part of the popliteal space. From the sural arteries also arise the superficial sural or cutaneous branches which pass downward between the two heads of the gastrocnemius, and, perforating the deep fascia, supply the skin and fascia of the calf. A branch, usually of moderate size, accompanies the small saphenous vein, and is sometimes called the posterior saphenous artery.
(2) The articular, five in number, are divided into two superior (medial and lateral), two inferior (medial and lateral), and the middle or azygos. The superior and inferior come off transversely in pairs from either side of the popliteal, the superior above, the inferior below the joint. Winding round the bones to the front of the knee, they form — by anastomosing with each other and with the genu suprema (anastomotica magna) , the termination of the profunda, the descending branch of the lateral circumflex, and the anterior tibial recurrent — a superficial and deep arterial rete (fig. 499). The superficial anastomosis or rete lies between the skin and fascia round about the patella (patellar rete), which it supplies, the larger branches entering it from above. The deep anastomosis or articular rete [rete articularis genu] lies on the surface of the bones around the articular surfaces of the femur and tibia, supplying branches to the contiguous bones and to the joints. The middle articular is a single short trunk coming off from the deep surface of the popliteal artery. It at once passes through the posterior ligament into the joint.
(o) The superior lateral articular artery [a. genu superior lateralis], the larger of the two superior articular branches, runs in a lateral direction above the lateral head of the gastrocnemius, and, passing beneath the biceps and through the lateral intermuscular septum and vastus lateralis, enters the substance of the vastus intermedins (erureus), and anastomoses, above with the descending branch of the lateral circumflex, below with the inferior lateral articular, and across the front of the femur with the superior medial articular, the genu suprema (anastomotica magna), and termination of the profunda, forming with them, as already described, the deep articular rete. Branches are given off to the patella, to the upper and lateral part of the joint, to the bone, and to the contiguous muscles.
(6) The superior medial articular artery [a. genu superior mediaUs] (fig. 499) runs medially just above the medial head of the gastrocnemius, beneath the semi-membranosus, and, after perforating the tendon of the adductor magnus, enters the substance of the vastus medialis. Here it anastomoses with the deep branch of the genu suprema (anastomotica magna) and termination of the profunda above, with the inferior medial articular below, and with the superior lateral articular across the front of the femur. It supphes small branches to the contiguous muscles, to the femur, to the patella, and to the joint.
(c) The inferior medial articular artery [a. genu inferior mediaUs], the larger of the two inferior articular arteries, passes in an obliquely medial direction across the pophteus, below the medial condyle (tuberosity) of the tibia and beneath the tibial collateral ligament to the front and
medial side of the knee-joint. Here it anastomoses (fig. 499), above witli the superior medial articular and the superficial branch of the genu suprema (anastomotica magna), and across the front of the tibia with the inferior lateral articular. It supphes branches to the lower and medial part of the joint.
(d) The inferior lateral articular artery [a. genu inferior lateralis] passes laterally above the head of the fibula, along the tendon of the popliteus muscle, beneath the lateral head of the gastrocnemius, and then under the tendon of the biceps, and between the long and short fibular
collaterallligaments. Then winding to the front of the joint, it anastomoses above with the superior lateral articular, below with the anterior tibial recurrent, and across the front of the tibia with the inferior medial articular. It also supplies branches to the lateral and lower part of the joint.
The posterior tibial artery [a. tibialis posterior] (fig. 500) , the larger of the two branches into which the popliteal divides at the lower border of the popliteus muscle, runs downward on the flexor aspect of the leg between the superficial and deep muscles to the back of the medial malleolus. Midway between the tip of the malleolus and the calcaneus, and under cover of the origin of the abductor hallucis as it arises from the laciniate (internal annular) ligament, it divides into the medial and lateral plantar arteries.
The artery is first situated midway between the tibia and fibula, and is deeply placed beneath the muscles of the calf. As it passes downward it inclines to the medial side and at the lower third of the leg is superficial, being only covered by the skin and fasciae. At the ankle it lies beneath the laciniate ligament, and at its bifurcation also beneath the abductor hallucis. A line drawn from the centre of the popliteal space to a spot midway between the medial malleolus and point of the heel will indicate its course. In addition to the branches named below it supplies the muscles between which it passes, and the integument of the lower medial region of the leg.
Posteriorly, it is covered by the skin and fascia, the gastrocnemius and soleus, and the deep or intermuscular fascia of the leg, by which it is tightly bound down to the underlying muscles. It is crossed by the tibial nerve about 4 cm. (If in.) below its origin, after it has given off its
peroneal branch; the nerve first lies on the medial, and for the rest of its course on the lateral side of the vessel. It is accompanied by two veins, which send numerous anastomosing branches across it. In the lower third of the leg the artery is superficial, being covered only by the skin and^by the superficial and deep fascia?.
The branches of the posterior tibial artery are: — (1) The fibular; (2) the peroneal; (3) the tibial nutrient; (4) the communicating; (5) the posterior medial malleolar; (6) the medial calcanean, and (7) the terminal, medial and lateral plantar.
(1) The fibular or superior fibular branch [ramus fibularis], which frequently arises from the beginning of the anterior tibial, runs upward and laterally toward the head of the fibula. It is small and gives twigs to the soleus, peroneus longus, and extensor digitorum longus, and anastomoses with the inferior lateral articular and the lateral sural arteries.
(2) The peroneal artery [a. peronea] is a large vessel which (figs. 498, 500), arises from the posterior tibial about 2.5 cm. (1 in.) below the lower border of the popliteus muscle. At first forming a gentle curve convex laterally, it approaches the fibula, and continues its course downward close to that bone as far as the lower end of the interosseous membrane, where it gives off a large branch, the perforating (anterior peroneal), and then, passing over the back of the inferior tibio-fibular joint, terminates by breaking up into a network, which is distributed over the back of the lateral malleolus and lateral surface of the calcaneus (figs. 500, 504). It is accompanied b}^ two vense comitantes. Besides the named branches it supplies twigs to the flexor hallucis longus, tibialis posterior, tibialis anterior, peronei and soleus; also to the integument on the lateral side of the leg.
Relations. — At its upper part it is deeply placed between the tibialis posterior and soleus muscles, and beneath the deep or intermuscular fascia. For the rest of its course to the ankle it Ues beneath, or sometimes in the substance of, the flexor hallucis longus in the angle between the fibula and interosseous membrane. After giving off the perforating branch, it is only covered, as it lies behind the tibio-fibular articulation, by the integuments and deep fascia, and in this part of its course is sometimes called the posterior peroneal.
The branches of the peroneal artery are: — (a) The perforating (anterior peroneal) ; (b) the fibular nutrient; (c) the communicating; (d) the lateral malleolar; (e) the lateral calcanean; and (/) the terminal.
(o) The perforating (or anterior peroneal) branch [ramus perforans] arises from the front of the peroneal artery at the lower part of the interosseous space, and, passing through the interosseous membrane, runs downward over the front of the inferior tibio-fibular joint, beneath the peroneus tertius, and supplies this muscle and the inferior tibio-fibular joint. It anastomoses with the tarsal, arcuate (metatarsal) and lateral malleolar branches of the anterior tibial artery, and with the lateral plantar artery on the lateral side of the foot, forming a plexus over the ankle (fig. 503).
(cj The communicating branch [ramus communicans] passes medially in front of the tendo Achillis to anastomose with the communicating branch of the posterior tibial. The usual situation of this communication is from 2.5 to 5 cm. (1 to 2 in.) above the ankle-joint.
anastomoses with the other arteries distributed to the lateral malleolus and heel.
(3) The tibial nutrient artery [a. nutritia tibiae], a vessel of large size, leaves the posterior tibial at its upper part, pierces the tibialis posterior, and enters the nutrient foramen in the upper third of the posterior surface of the tibia. In the interior of the bone it divides into two branches: an ascending or smaller, which runs upward toward the head of the bone; and a descending or larger, which courses downward toward the lower end. It gives off two or three muscular twigs to the tibialis posterior before it enters the foramen. The nutrient artery of the tibia is the largest nutrient artery of bone in the body, and is accompanied by a nerve given off by the nerve to the popliteus.
(4) The communicating branch [ramus communicans] arises from the posterior tibial about 5 cm. (2 in.) above the medial malleolus, and, passing transversely across the tibia beneath the flexor hallucis longus and tendo Achillis, anastomoses with the communicating branch of the peroneal.
arteries is hkewise present in the loose connective tissue beneath or behind the tendo Achillis.
(5) The posterior medial malleolar branch [ramus maUeolaris posterior medialis] divides for distribution over the medial malleolus, anastomosing with the other arteries entering into the medial malleolar rete [rete m.iUeolare mediale] which is formed over the portion of bone. In its course to the malleolus it runs beneath the flexor digitorum longus and tibiaUs posterior muscles.
(6) The medial calcanean branches [rami calcanei mediales] are distributed to the soft parts over the medial side of the calcaneus. These branches come off from the posterior tibial just before its bifurcation, and anastomose with the medial malleolar and pei'oneal arteries.
THE LATERAL PLANTAR ARTERY
The lateral plantar artery [a. plantaris lateralis] (figs. 501, 502) — the larger of the two branches into which the posterior tibial divides beneath the laciniate (internal annular) ligament — passes at first laterally and forward across the sole of the foot to the base of the fifth metatarsal bone, where it bends medially, and still running forward sinks deeply into the foot and terminates at the proximal end of the first interosseous space by anastomosing with the deep plantar (communicating) branch of the dorsal artery of the foot. In its course to the fifth metatarsal bone the artery runs in a more or less straight line obliquely across the foot ; whilst its deep portion, extending from thefif th metatarsal bone to the proximal
tarsal to lateral side of great toe
end of the first interosseous space, forms a slight curve with the convexity forward, and is known as the plantar arch. The plantar arch is comparable to the deep volar arch formed by the deep branch of the ulnar anastomosing with the radial through the first interosseous space. This homology is at times more complete in that the deep plantar (communicating) branch of the dorsalis pedis, the homologue of the radial in the upper limb, takes the chief share in forming the arch. The lateral plantar artery is accompanied by two veins. The course of the artery is indicated by a line drawn across the sole of the foot from a point midway between the tip of the medial malleolus and the medial tubercle of the calcaneus to the base of the fifth metatarsal bone, and thence to the lateral side of the base of the first metatarsal.
mose with arteries on tlie lateral side of the dorsum.
Relations. — In the first part of its course from the medial malleolus to the base of the fifth metatarsal bone, the artery is covered successively by the abductor hallucis and the flexor digitorum brevis, by which it is separated from the plantar aponeurosis, and may be slightly overlapped in muscular subjects by the abductor quinti digiti. As it approches the base of the fifth metatarsal bone it Ues, as it turns medially before sinking into the foot, in the interspace between the flexor digitorum brevis and the abductor quinti digiti, and is here covered only by the skin and superficial fascia and the plantar aponeurosis. It hes upon the calcaneus, the quadratus plantse (flexor accessorius), and the flexor digiti quinti brevis. It is accompanied by the lateral plantar nerve, the smaller of the two divisions into which the tibial nerve divides. In this part of its course it gives off small branches to the contiguous muscles and to the heel.
In the second part of its course the artery, which is here known as the plantar arch [arcus plantaris], sinks into the sole, and is covered, in addition to the skin, superficial fascia, plantar aponeurosis, and flexor digitorum brevis by the tendons of the flexor digitorum longus, the lumbricales, branches of the medial plantar nerve, and the adductor hallucis. It lies upon the proximal ends of the second, third, and fourth metatarsal bones and the corresponding interosseous muscles.
(1) The perforating branches [rr. perforantes], three in numbers, ascend through the proximal end of the second, third, and fourth spaces, between the two heads of the correspondingly named dorsal interosseous muscles, and communicate with the proximal ends of the first, second, and third dorsal metatarsal (interosseous) arteries (fig. 502).
(2) The plantar metatarsal arteries [aa. metatarsete plantares] are usually four in number, and pass forward in the four intermetatarsal spaces, which are numbered from the medial side. They rest upon the interosseous muscles of their spaces, and are at first under cover of the lumbricals, but as they approach the clefts of the toes each divides into two branches, the plantar digital arteries [aa. digitales plantares], which supply the contiguous sides of the toes. The plantar digital branch for the medial side of the great toe is usually given off by the first plantar metatarsal; that for the lateral side of the Uttle toe is usually a separate branch from the lateral end of the plantar arch.
The plantar metatarsal arteries, immediately before they bifurcate, send to the dorsum of the foot a perforating branch each to the corresponding dorsal metatarsal arteries. They anastomose by many small twigs with the dorsal metatarsal arteries, which also run along the sides of the metatarsal bones, but more toward the dorsal aspect. Immediately above each phalangeal joint the plantar digital vessels communicate by cross branches, forming a rete for the supply of the articular end of the phalanges and the contiguous joints. At the distal end of the toes they also freely anastomose with each other, forming a rete beneath the pulp and around the matrix of the nail. The metatarsal and digital arteries are each accompanied by two small veins.
The medial plantar artery [a. plantaris medialis] (figs. 501, 502) — much the smaller of the two divisions into which the posterior tibial divides, passes forward along the medial side of the sole of the foot usually to the first interosseous space. Here it ends by anastomosing either with the first plantar metatarsal artery derived from the plantar arch, or with the branch given off by the first plantar metatarsal to the medial side of the great toe.
Relations. — The artery is at first under cover of the abductor hallucis, but afterward Ues in the interval between that muscle and the flexor digitorum brevis. It is covered by the skin and superficial fascia, but not by the plantar aponeurosis, since it lies between the central and medial portions of that structure.
(1) The deep branch [ramus profundus], which at once divides — or it may come off as several branches — to supply the muscles, articulations,and integument of the medial side of the sole. Some of these branches form an anastomosis aroundthe medial margin of the foot, with branches of the dorsahs pedis.
(2) The superficial branch [ramus superficialis] breaks up into very small twigs which accompany the digital branches of the medial plantar nerves, and anastomose with the plantar metatarsal arteries in the first, second, and third spaces. At times a twig from one of these branches joins the lateral plantar artery to form a superficial plantar arch.
The anterior tibial artery [a. tibialis anterior] fig. 503 — the smaller of the two branches into which the popliteal artery divides at the lower border of the popliteus muscle — at first courses forward between the two heads of origin of the tibialis posterior, and, after passing between the tibia and fibula above the upper part of the interosseous membrane, runs downward on the front and lateral aspect of the leg, between the anterior muscles, as far as the front of the ankle-joint. Below the joint it is known as the dorsalis pedis. The course of the vessel is indicated by a line drawn from the front of the head of the fibula to a point midway between the two malleoli.
The artery is accompanied by two veins which communicate with each other at frequent intervals across it. It is also accompanied in the lower three-fourths of its course by the deep pei'oneal nerve. The nerve, which winds round the head of the fibula, and pierces the extensor digitorum longus, first comes into contact with the lateral side of the artery about the upper third of the leg; in the middle third it is a little in front of the artery, and in the lower third again lies to its lateral side. In addition to the named branches the anterior tibial artery supplies muscular twigs to the extensors of the toes and the tibiahs anterior.
Relations. — The artery at first Ues in the triangle formed by the two heads of the tibiahs posterior and the popliteus muscle; and, as it passes above the interosseous membrane, it has the tibia on one side and the fibula on the other. It is separated from the deep peroneal (anterior tibial) nerve at its commencement by the neck of the fibula and the extensor digitorum longus. This arrangement is homologous with that met with in the forearm in the case of the posterior interosseous artery and deep radial (posterior interosseous) nerve.
Posteriorly in its course down the leg it lies in its upper two-thirds upon the interosseous membrane, to which it is closely bound by fibrous bands; and in its lower tliird upon the front of the tibia and the ankle-joint.
To its medial side along its upper two-thirds is the tibialis anterior muscle; but at the lower third it is crossed by the tendon of the extensor hallucis longus and then for the rest of its course has this tendon overlapping it or to its medial side.
On its lateral side it is in contact in its upper third with the extensor digitorum longus muscle; in its middle third with the extensor hallucis longus; but, as this muscle crosses to the medial side of the artery, the vessel usually for a very short part of its course comes again
into contact with the extensor digitorum longus. At the upper and lower thirds of its course on the front of the leg the artery has the deep peroneal (anterior tibial) nerve to its lateral side. In front the artery is covered by the skin, superficial and deep fascia. In its upper twothirds it is deeply placed in the cellular interval between the tibiahs anterior on the medial side and the extensor digitorum longus and extensor hallucis longus on its lateral side; and in .its lower third it is crossed in the latero-medial direction by the tendon of the extensor
irregularly to the adjacent muscles along the artery.
(1) The posterior tibial recurrent artery [a. recurrens tibialis posterior] is occasionally absent. It ascends between the popliteus muscle and the popliteal ligament of the knee-joint, supplying these structures and the superior tibio-fibular joint. It anastomoses with the inferior lateral articular branch of the pophteal, and to a less extent with the inferior medial articular branch.
(2) The anterior tibial recurrent [a. recurrens tibiahs anterior] is given off from the anterior tibial artery immediately after that vessel has passed above the interosseous membrane. It winds tortuously through the substance of the tibialis anterior muscle, over the lateral condyle (tuberosity) of the tibia close to the bone; and, perforating the deep fascia, ramifies on the lower and lateral part of the capsule of the knee-joint. It anastomoses with the inferior and superior lateral articular branches of the pophteal, with the descending branch of the lateral circumflex, and somewhat less freely with the medial articular branches of the pophteal and with the genu suprema (anastomotica magna). It gives off small branches to the tibialis anterior, the extensor digitorum longus, the knee-joint, and the contiguous fascia and skin. It forms one of the collateral cliannels by which the blood is carried to the hmb below in obstruction of the pophteal artery (fig. 503).
(3) The medial malleolar [a. maUeolaris anterior medialisj, the smaller of the two malleolar branches, arises from the lower part of the anterior tibial artery a httle higher than the lateral, usually about the spot where the tendon of the extensor haUucis longus crosses the anterior tibial artery. It winds over the medial malleolus, passing beneath the tibiaUs anterior, and joins the medial malleolar rete anastomosing with branches from the posterior tibial artery.
(4) The lateral malleolar artery [a. maUeolaris anterior lateralis], larger than the medial, arises from the lateral side of the anterior tibial artery, usually on a lower level than the medial malleolar. It winds downward and laterally round the lateral malleolus, passing beneath the extensor digitorum longus and peroneus tertius, and joins the lateral malleolar rete by anastomosing with the perforating peroneal, the termination of the peroneal, and the lateral tarsal branch of the dorsahs pedis (fig. 503).
The anastomosis between the lateral malleolar and perforating peroneal is sometimes of considerable size, supplying the blood to the dorsal artery of the foot; the anterior tibial, then much reduced in size, usually ends at the place of origin of the lateral malleolar.
THE DORSALIS PEDIS ARTERY
The dorsalis pedis artery [a. dorsalis pedis] (fig. 503) is a continuation of the anterior tibial. It extends from the front of the ankle-joint to the proximal end of the first interosseous space, where it ends, as the deep plantar branch, by joining the lateral plantar artery to complete the plantar arch. It is accompanied by two venae comitantes. The course of the artery is indicated by a fine drawn from a point midway between the two malleoli to the proximal end of the first metatarsal space.
Relations. — Behind, the artery from above downward Ues successively on the talus (astragalus), navicular, second cuneiform, and the base of the second metatarsal bones, and the hgaments uniting these bones. At times its course is a little more lateral, lying either partly on the second cuneiform bone, or on the dorsal ligaments uniting the second cuneiform to the first cuneiform. It is more or less bound down to the bones by aponeurotic fibres derived from the deep fascia.
In front, the artery is covered by the crucial (anterior annular) hgament, sometimes by the extensor hallucis longus, by the skin, the superficial and deep fascia, and, just before its termination, by the tendon of the extensor hallucis brevis. The angle formed by this tendon with the extensor hallucis longus is the best guide to finding the artery in the process of Ugature (fig. 503).
(1) The tarsal branches may be divided into (a) the lateral and (6) the medial, (a) The lateral tarsal artery [a. tarsea lateraUs] runs laterally over the navicular and cuboid bones beneath the extensor digitorum brevis. It supplies branches to that muscle, and to the bones and the articulations between them, and anastomoses above with the lateral malleolar and perforating (anterior) peroneal, below with the arcuate (metatarsal) and, over the lateral border of the foot, with the anastomotic branches of the lateral plantar artery. (6) The medial tarsal arteries [aa. tarseai raediales] consists of a few small branches which run over the medial side of the foot, supplying the skin and articulations, and anastomose with the medial malleolar.
(2) The arcuate (metatarsal) artery Ja. arcuata] (figs. 503, 504) runs laterally across the foot, in a shght curve with the convexity forward, over the bases of the metatarsal bones, and beneath the e.xtensor tendons and the extensor digitorum brevis. At the lateral border of the foot it anastomoses, with the lateral tarsal, and with branches of the lateral plantar.
MORPHOGENESIS OF THE ARTERIES 633
lYom the oonvexity of the arch it gives off four dorsal metatarsal (interosseous) arteries, which run forward on the dorsal interosseous muscles in the centre of the four interosseous spaces to the cleft of the toes, where they bifurcate for the supply of the contiguous sides of the toes. The artery to the first space is large, and gives off the digital artery to the medial side of the great toe. This vessel continues the direction of the dorsalis pedis and is commonly known as the dorsalis hallucis artery. The most lateral of the interosseous branches gives off a small vessel for the supply of the lateral side of the little toe. At the proximal end of the second, third, and fourth interosseous spaces each artery receives a perforating branch from the lateral plantar artery, and immediately before they bifurcate a second perforating artery through the distal end of the interosseous space from the corresponding digital.
The dorsal digital arteries [aa. digitales dorsales], into which the dorsal metatarsal arteries divide at the cleft of the toes, run along the side of each toe toward the dorsal aspect, anastomosing with each other across the dorsum of the toes and by frequent branches with the digital branches of the plantar metatarsal arteries, which also run along the sides of the toes, but nearer the plantar surface. At the end of the toes they anastomose with each other around the quick of the nail.
(3) The deep plantar branch [ramus plantaris profundus] comes off from the dorsaUs pedis with the first dorsal metatarsal (into which arteries indeed the dorsalis pedis may be said to divide). At the back of the first interosseous space it dips into the sole between the two heads of the first dorsal interosseous muscle, and communicates with the termination of the lateral plantar artery, completing the plantar arch, in a manner similar to that in which the radial artery, passing through the first dorsal interosseous muscle in the hand, completes by anastomosing with the ulnar the deep palmar arch.
In conformity with the branchiomeric and metameric development of the head and trunk (see p. 15) the arteries are developed in two sets, the branchiomeric (aortic arches) and metameric (segmental arteries).
Sixth aortic arch
(1) The system of aortic arches consists of five pairs of arteries which spring from the ventral aorta, or aortoe, and pass around the pharynx in the branchial arches to join the paired dorsal aorta;. Some of the arches are veiy transitory, but all those that give rise to permanent vessels are present in embryos about five miUimetres in length. Fig. 505 shows their distribution and rlations to the pharyngeal pouches at this stage; the arches which appear fifth in order are regarded as the sixth because (like the sixth arches in lung-fish and amphibia) they give
off the pulmonary arteries. The true fifth arches are probably not always developed, but when they occur they are later in development, imperfect, and very transitory. The dorsal aortEe, originally paired, are now united to form a single vessel as far forward as a place slightly caudal to the sixth arches.
During the separation of the heart into right and left halves (p 526.), the primitive ventral aorta is divided by the aortic septum into two vessels, the main pulmonary artery and the ascending aorta of the adult. The pulmonary trunk becomes connected with the sixth pair of arches only; the other arches then communicate, by means of the aorta, with the left ventricle. The further changes which occur in the arches to bring about the conditions found in the adult are shown diagrammatioally in fig. 506. The right and left pulmonary arteries arise from the corresponding sixth arches. The portion of the sixth arch dorsal to the pulmonary artery disappears on the right, on the left it persists until birth as the ductus arteriosus (lig. arteriosum of the adult). The fourth arch, including the short ventral stem between the fourth and sixth arch, becomes the permanent aortic arch on the left side, and the innominate and proximal portion of the subclavian upon the right. The dorsal longitudinal stem disappears on both sides between the third and fourth arches, and on the right side from the sixth arch back to the unpaired dorsal aorta. A trace of the latter portion of the right dorsal stem frequently persists in the adult as a small vessel (a. aberrans) connecting the dorsal aorta, directly or indirectly, with the right subclavian artery (p. 590). The ventral stems between the fourth and third arches form the common carotids; those between the third and first become the external carotids. The internal carotids are formed by the third arches and tlie dorsal stems between the third and first arches. The first and second arches disappear early, contributing somewhat to the formation of the branches of the internal and external carotids.
The primitive aortic arches (1-6), and some of the cervical dorsal segmentals (V-VIII) are shown in all the diagrams but numbered in Y only. X., abnormal: the aortic arch is on the right; the left subclavian takes the dorsal course; the right vertebral arises direct from the aortic arch. Y., normal; Z., abnormal: the right subclavian arises from the sixth cervical dorsal segmental; the left from the sixth and seventh. A, ascending aorta; AA, aortic arch; AD, dorsal 'aorta ; CC, common carotid; CE, external carotid; CI, internal carotid; D, ductus arteriosus; IN, innominate; S, subclavian; T, costo-cervical; V, vertebral.
In early development the segmental arteries are caudally placed with regard to the aortic arch vessels. As the latter, however, become shifted following the migration of the heart from the neck into the thorax, the persistent seventh dorsal cervical segmental (subclavian) reaches the neighbourhood of the sixth aortic arch.
Little is known of the share taken by the first and second aortic arches in the formation of the branches of the internal and external carotid arteries. It has been shown by Tandler that the internal maxillary is prirnarily a branch of the internal carotid, (the first and second arches taking a share in its formation). The primitive vessel is known as the stapedial since it passes between the crura of the developing stapes. It gives off supraorbital, infraorbital, and mandibular branches; the latter two arising from the main artery by a common trunk. The common trunk is later joined by a branch from the external carotid and, together with the supraorbital, becomes the middle meningeal. An anastomosis between the supraorbital and the ophthalmic persists 80 that in the adult the anterior branch of the meningeal frequently takes a considerable share in the blood-supply of the orbit. The stapedial trunk undergoes retrogression and is represented in the adult by the carotico-tympanic of the internal carotid and by the superior tympanic of the middle meningeal. The infraorbital branch of the stapedial becomes the second and third parts of the internal maxillary and gives off branches accordingly. The mandibular branch becomes the inferior alveolar of the adult.
(2) The segmental system (fig. 507) consists of arteries primarily arising from the aorta in three longitudinal series, dorsal, lateral, and ventral on either side. The segmental arrangement is much less perfect in the ventral and lateral groups than in the dorsal. So much so, in fact, that the term segmental is used for the ventral and lateral groups rather as a matter
of convenience than as indicating a strict numerical correspondence between segments and
The dorsal segmental arteries primarily supply the central nervous system but later give off two sets of vessels to the body wall; these persist in the adult as the anterior and posterior main branches of the intercostal and lumbar arteries. The remainder of each segmental artery is represented in the adult by the spinal ramus which accompanies the corresponding nerve root through the intervertebral foramen. The tendency to form intersegmental anastomoses between these vessels (and their branches) gives rise to many of the important longitudinal stems of adult anatomy. Thus, the spinal ramus gives rise to a pre- and postneural anastomosing channel on either side, the (primarily paired) anterior and posterior spinal arteries. The anterior branches have each a longitudinal precostal anastomosis, and, as they grow forward with the developing body wall, their ends are connected to form the mammary anastomosis.
Two dorsal segmental arteries have been recognized in the occipital region, the first disappears and the second, the hypoglossus artery, follows the hypoglossal nerve to the ventral surface of the brain where it is connected with the termination of the internal carotid of its own side by means of a longitudinal stem the a. vertebralis cerebralis. The hypoglossus artery, by shifting forward to the third aortic arch, itself acquires a secondary origin from the internal carotid.
In the cervical region, the spinal ramus of segmental cervical I forms the third, or sub' occipital, part of the vertebral artery. Cervical segmentals I to VI lose their connection with the aorta and a postcostal anastomosis between them forms the second part of the same artery. The first part of the vertebral is formed by the posterior ramus of cervical VI and its precostal anastomosis with cervical VII (subclavian) (fig. 508).
Anterior perforating branch
The anterior ramus of cervical VII forms the entire first part of the subclavian on the left, and the distal portion of it upon the right (see system of aortic arches). The second part of the subclavian is formed by the lateral branch of the anterior ramus of cervical VII, while the portion of the anterior ramus ventral to this becomes the root of the internal mammary. The anterior ramus of cervical VIII disappears, but the pi'ecostal anastomosis connecting it with the subclavian (cervical VII) persists to form the costo-cervical of the adult. The posterior ramus of cervical VIII forms the root of the deep cervical, and, by a postvertebral anastomosis with the other posterior cervical rami and with the occipital, forms the remainder of the deep cervical and the descending branch of the occipital artery.
In the thoracic and lumbar regions, the embryonic conditions very largely persist (fig. 508). The anterior rami of thoracic segmentals I and II, however, lose their connection with the aorta and, by a precostal anastomosis with cervical VIII, become secondarily connected (through the costo-cervical trunk) with the subclavian. The superior intercostal of the adult is thus formed. The fifth lumbar segmental apparently joins the umbihcal artery (of the ventral segmental series) to form the external ihac which, in the adult, provides the chief arterial supply to the lower extremity. The inferior gluteal (sciatic), which is the primitive artery of supply for the lower extremity, if it is segmental at all, belongs to the sacral region. The free ends of the anterior rami of all the thoracic and the upper four lumbar segmentals become united, as they grow out with the body wall, to form the longitudinal mammary anastomosis (fig. 508). This anastomosis, by its connection with the anterior ramus of cervical
arteries of the adult.
In the sacral region, the adult shows evidence of segmental vessels in branches of the middle and lateral sacral arteries; the latter probably representing a precostal anastomosis. Whether the parietal branches may be derived directly from segmental sources, or whether they are vessels of new formation, has not been determined embryologicaUy. The obturator would appear to be segmentalifor it contributes a branch to the mammary anastomosis which persists in the adult (pubic brandies of obturator and inferior epigastric). If the connecting branch with the inferior epigastric is large, the obturator may lose its connection with the hypogastric, in which case the latter is said to arise from the former, or from the external iliac,
One of the most interesting of the longitudinal anastomoses in connection with the dorsal segmentals is the primitively bilateral preneural anastomosis extending ventral to the spinal cord 'and connected, beyond the first spinal segment, with each internal carotid by means of the right and left aa. cerebrales vertebrales. The hypoglossus artery (p. 635) having lost its connection with the internal carotid, leaves the spinal ramus of cervical I (third part of the subclavian) to take over the major share of the cerebral supply. A process of blending by anas-
tomosis now occurs resulting in the single basilar and anterior spinal arteries of the adult. The posterior communicating, proximal portions of the posterior cerebrals, the fourth part of the vevtebrals, and the right and left roots in the anterior spinals of the adult alone retain the primitive arrangement and testify to the double nature of the original anastomosis. Asymmetry in the vertebrals and other irregularities in the adult can usually be explained on developmental grounds. The postneural anastomosis, which joins the preneural at about the first cervical segment, retains its bilaterality throughout to form tlie paired posterior spinal arteries of the adult. The lateral segmental arteries take origin from the aorta in series, intermediate in position between the dorsal and ventral segmentals. They reach their fullest development in embryos of about 8 mm., when they extend from the seventh cervical to the twelfth thoracic segment and supply the mesonephros. At this stage Broman found twenty arteries on each side, many of which were non-segmental. As the suprarenals and gonads develop, they each receive branches from several mesonephric arteries. The latter arteries now undergo rapid retrogression and the suprarenal and gonadie branches are shifted caudally through the mesonephric series to newly formed (non-segmental) arteries opposite the upper lumbar segments. Finally there remain three suprarenal arteries opposite the twelfth thoracic and first and second lumbar segments and a gonadie artery {ovarian or internal spermatic of the adult) opposite the third lumbar segment. AU of these vessels now appear to be direct branches from the aorta. Of the three suprarenal branches, the upper and lower each gives a large branch to the diaphragm and kidney respectively and become the inferior phrenic and renal arteries of the adult. The middle becomes the middle suprarenal of the adult. Felix puts a somewhat different interpretation upon the origin of the vessels persisting in the lumbar region after the disappearance of the thoracic mesonephric arteries. He finds in an embryo of 18 mm. nine arteries on either side, extending from the ninth thoracic to the third lumbar segment, all of which he looks upon as mesonephric. These he classifies into tlxree groups: — Cranial, which reach the mesonephros by passing dorsal to the suprarenal; caudal which pass ventral to the suprarenal, and middle which pass through it. Inasmuch as the arteries anastomose in the mesonephros there is great liability to variation in the number and position of the stems which persist in the adult. The suprarenal arteries
are usually derived from the caudal group, the renals from the caudal or middle and the spermatics from the middle. When accessory renals or spermatics occur in the adult their place of origin and course will generally indicate the group from which they are derived.
The ventral segmental arteries appear very early. In an embryo of seven somites (ca. 2 mm.) described by Dandy* there was a right and a left series of twelve arteries, each arising from the still ununited dorsal aortce, the artery at the caudal end of each series being the umbihcal, and the remainder vitelline arteries. In an embryo of 4.9 mm. (35 somites) described by IngaUst the originally paired viteUine arteries had united (as had the dorsal aortffi in part) to form unpaired vessels. There were unpaired vessels as follows: one opposite the seventh cervical segment (co^hac); five opposite the first four thoracic (omphalo-mesenterics, united by a longitudinal anastomosis), and one vessel of doubtful significance opposite the fifth and sixth thoracic segments. The paired umbiUoal arteries were opposite the first lumbar segment. No other ventral arteries were present.
It has been found from more fully developed stages that the inferior mesenteric artei-y is distinguishable at a stage of 8 mm. opposite the second lumbar segment. Also that the ventral segmental vessels undergo a process of migration until they reach their definitive positions, i. e., the coeliac opposite the twelfth thoracic segment, the superior mesenteric opposite the first, the inferior mesenteric opposite the third, and the umbilicals opposite the fourth lumbar segments, respectively. The cesophageal arteries of the adult do not belong to this series; but seem to be vessels of later formation.
The umbilical arteries, by means of secondary anastomosis, move laterally upon the aorta so as to pass lateral to the Wolffian ducts instead of medial . The proximal portion of each umbilical artery becomes the common iliac of the adult; its continuation is represented by the hypogastric and its umbilical branch. The external iliac appears to be derived from the dorsal segmental artery of the fifth lumbar segment, and the parietal branches of the hypogastric from corresponding sacral segmentals acquired by anastomosis. How such anastomoses between the umbihcals and the dorsal segmentals come about has not been ascertained.
2. VARIATIONS
Aorta and pulmonary artery. — The variations met with in the arch of the aorta are usually to be explained as persistent foetal conditions, and are often associated with abnormahties of the heart. Many of the variations are due to different modes of transformation of the primitive system of aortic arches. Since the aorta and pulmonary artery develop from a common conus and truncus arteriosus, irregular and imperfect development of the aortic septum may also produce numerous variations.
It has been seen that at one stage of development two fourth arches, a right and a left, are present, and such a condition is occasionally persistent in the adult. In such cases, owing to the portion of the aorta derived from the bulbus arteriosus being directed upward and to the right and the descending aorta lying in the left side of the vertebral column, the right arch passes from right to left behind the oesophagus, which thus seems to perforate the aortic arch.
Another variation occasionally seen is the occurrence of an aortic arch curving to the right instead of the left. This may be due to a persistence of the lower portion of the right dorsal longitudinal stem and the disappearance of the left, as shown in fig. 506; or it may be associated with a complete inversion of all the viscera, a situs inversus.
If the lower portion of the right dorsal longitudinal trunk should persist, and the part of it which normally forms the proximal part of the right subclavian should disappear, the right subclavian would arise from the descending portion of the aortic arch. It is to be noted that in such cases the subclavian passes behind the oesophagus and below the right inferior laryngeal nerve. Partial persistence of the lower portion of the right dorsal longitudinal trunk is represented in the arteria aberrans (see p. 590).
Another group of variations is based on the persistence of the ductus arteriosus, which is derived from the sixth aortic arch. With this group belong the cases in which the pulmonary artery arises from the aorta; that is, where the blood of the pulmonary arteries passes from the aorta through the ductus arteriosus.
Variations in the number and the position of the vessels arising from the arch are extremely great, and many of these conditions are found normally in other mammals or birds. There may be from one to six branches. The case of one branch is the normal in the horse. It involves the fusion of the two aortic stems and the shortening of the fourth arch so that the left subclavian joins with the common stem. The avian form with trto innominate arteries is extremely rare. A more common form is the one found in most apes, in which the innominate and left carotid form one branch ; in rare instances the three branches are the two subclavians and a general carotid artery. When there are more than three branches the vertebral arteries are added, or the extra branch may be the thyreoidea ima (fig. 443). The commonest form with four vessels is the one in which the left vertebral arises between the left carotid and subclavian. A rarer form is to be found when the order is right subclavian, right carotid, left carotid, and left subclavian. Where there are five arteries, the extra ones are the right subclavian and left vertebral. The case of six branches is due to the separate origin of both vertebrals and both subclavians. The manner in which the vertebral artery may arise from the adult aortic arch is indicated in fig. 506.
The innominate artery may be absent, or may give off additional branches (see Aokta). It may be longer than usual and, bending to the left, ascend in front of the trachea (or more rarely behind the trachea and oesophagus) to turn again to the right. The thyroidea ima has been referred to (p. 532).
Itjmay not bifurcate at all, in which case the branches usually arising from the external carotid are derived from the common. The ascending pharyngeal and superior thyreoid occasionally arise from an otherwise normal common carotid. Unusual origin ^of the common carotids has been referred to (see Aorta).
Branches of the carotid arteries. — The superior thyreoid, lingual and external maxillary sometimes have a common stem of origin. The superior thyreoid artery varies in size inversely with the inferior. The external maxillary occasionally terminates in its submental branch. In such cases the main supply of the face is taken over by an abnormally large dorsal nasal branch of the ophthalmic, or transverse facial branch of the temporal artery. The occipital sometimes arises from the internal carotid or from the ascending cervical. The ascending pharyngeal is very variable in its place of origin from the external carotid, it may arise from the common or internal.
Out of 447 arteries examined, the second portion of the internal maxillary passed lateral to the external pterygoid muscle in 55 per cent., and medial to it in 45 per cent, of cases. When medial to this muscle the internal maxillary sometimes passes medial to the inferior alveolar and lingual nerves and occasionally between them. The variability in the course of this artery appears to depend on a tendency to reduplication of the infraorbital branch of the stapedial artery (p. 634) in the neighbourhood of the mandibular nerve. Such a condition was found by Thyng in a 17 mm. human embryo. When the internal maxiUary passes medial to the external pterygoid there is often a parallel anastomosing channel between the posterior deep temporal and buccal branches.
The branches of the subclavian artery are very variable in their place of origin (p. 559). The vertebral may arise directly from the arch of the aorta (p. 537) or take an unusual course in the neck. It may enter the foramen transversarium of the fourth or fifth cervical vertebra instead of the sixth; this arises from substitution of an embryonic precostal anastomosis in these segments for the usual postcostal. By a converse substitution it may enter the seventh. The aa. transversa colli and scapulas vary inversely in size. The arteria aberrans connecting the right subclavian with the dorsal aorta has been referred to (p. 634).
Branches of the thoracic aorta. — The intercostal arteries are hable to numerical variation, evidently owing to the occurrence of precostal intersegmental anastomoses between the embryonic dorsal segmentals. A common longitudinal stem may even take over the vessels of both sides. The anterior spinal artery usually shows lack of median symmetry which indicates the bilaterality of its origin (p. 636). The arrangement of the bronchial arteries is hable to, much variation; this has not received adequate explanation.
The abdominal aorta sometimes divides as low as the fifth lumbar vertebra, occasionally higher than usual, depending upon the definitive position taken by the umbiUcal arteries (p. 637). Cases are on record of accessoiy pulmonary arteries arising by a single stem from the abdommal aorta, which passes into the thorax along the oesophagus. The aorta and vena cava inferior may be transposed either as a part of situs inversus or as an abnormality of the venous system.
Branches of the abdominal aorta. — The lumbar arteries are subject to the same type of variation as occurs in the intercostals. There may be a loop connecting the caeliac and superior mesenteric arteries. Any or all of the branches of the coeUac may arise from the superior mesenteric (coelio-mesenteric in the latter case) or directly from the aorta. The instabiUty of the coeUac and superior mesenteric branches is favored by the rapid cranio-caudal migration of the two trunks; intersegmental anastomosis, in some cases, may be a factor also. There is very great variation in the number of branches given off by the superior mesenteric and in the details of their arrangement. This is a natural result of the number of possible routes which may be taken by the blood; these resemble, in their variety, those of an embryonic circulation. The region of supply of the inferior mesenteric artery is sometimes taken over entirely or in part (e. g., middle colic) by the superior mesenteric. An omphalo-mesenteric artery, in rare cases, arises from the superior mesenteric or one of its branches. It passes to the navel and anastomoses with inferior epigastric and with the small arteries accompanying the round ligament of the liver or the urachus.
Accessory renal arteries are very common; as many as six have been recorded. These may arise from the aorta, middle sacral, inferior phrenic, middle suprarenal or internal spermatic. According to Felix, these are to be regarded as persistent mesonephric arteries. Those arising above the regular renal frequently enter the kidney dorsal to the hilum. Those below it are more apt to be ventraUy placed.
Nearly all possible varieties of origin are met with in the inferior phrenic, middle suprarenal, internal spermatic and accessory renal arteries which find explanation in the caudal migration of, and anastomosis between, the embryonic representatives of these vessels. The occasional origin of the inferior phrenic from the coeUac (or its branches) or from the superior mesenteric; of the internal spermatic or the middle suprarenal from the lumbar arteries, or of an accessory renal from the inferior mesenteric must be taken as indicating embryom'c anastomoses between the dorsal, lateral, or ventral segmental arteries, as the case may be.
The iliac and hypogastric arteries. — The length of the common iZiac depends upon the site of aortic bifurcation (p. 590) ; also upon the site of division of the common iliac into external iliac and hypogastric. If these spring directly from the aorta (as they do in rare cases) the common iliac is absent. The trunk formed by the common iliac and hypogastric is the proximal portion of the embryonic umbilical artery. The manner in which tliis takes over a dorsal segmental artery (probably the fifth lumbar) to become the external iliac is not sufficiently undersood to account for variations in this region.
The branches of the hypogastric artery show great variation in their origin, and there is frequently no separation of the hj'pogastrio into anterior and posterior divisions. Rarely the branches all take origin from the external iUao, in which case the hypogastric (as such) is absent. The obturator artery may arise from the inferior epigastric, or vice versa (p. 615). The arleria comitans n. ischiadici may be larger than usual and form a very pronounced anastomosis with the popliteal. In rare cases the main blood-supply of the lower limb is thus derived from the inferior gluteal which is the primitive embryonic condition (p. 640). .The vesical and vaginal arteries are liable to variation in their relative areas of distribution. The internal pudendal is sometimes small and maj' terminate as the perineal artery, in these cases the urogenital region is supplied largely by the accessory pudendal (p. 610).
At present there is little unanimity of opinion as to whether the pattern of the developing nerve trunks is specifically reproduced by the primitive arterial plexuses or whether the undoubted similarity between the two is of a more general nature. There occurs in either extremity one case in which an artery of fundamental importance follows a course practically independent of nerve distribution. The volar interosseous, in the forearm, and the peroneal, in the leg, are accompanied by insignificant nerves (n. to pronator quadratus, and n. to fie.xor hallucis longus respectively) which, moreover, do not ex-tend the full length of the arteries in question.
The blood of a developing limb, having traversed the proximal segment by means of the arterial plexus around a single nerve, has the choice of several possible paths by which to reach the digits. The selected channel becomes, for the time, the principal artery of the distal segment. This presently gives way to a second favoured route, which may persist or again give way to a third. Thus, finally, the adult arrangement is established. This process of alternation is the cause of many of the commoner variations for, if it does not proceed to its usual termination, a small vessel, commonly rated as a branch, may testify to its earher importance by appearing as one of the chief vessels of the part.
In the upper extremity the blood first traverses the peri-median plexus (which becomes later the axillo-brachial trunk) and flows to the digits mainly by the volar interosseous route. Next the volar interosseous d-nandles in favour of the median. The median afterward relinquishes its function to the radial and ulnar.
In the lower extremity the main blood-flow at first follows the peri-sciatic plexus from which it is dehvered to the digits chiefly by the peroneal artery. The peroneal artery passes from the sole to the dorsum of the foot through the sinus pedis, and from here suppUes the digits. The anterior and posterior tibial are at first small, the latter supplj-ing the plantar digital arteries. At a stage of 10 millimetres the femoral artery is represented by a peri-saphenous plexus which anastomoses with the peri-sciatic plexus near the knee. The peri-femoral plexus rapidly consoUdates into the femoral and genu suprema arteries. The femoral later takes over the pophleal as its direct continuation, and the origin of the genu suprema marks the boundary between the femoral and ischiadic zones of the main trunk. Finally the peroneal gives place to the anterior and posterior tibial arteries. The portion of the peroneal perforating the tarsus disappears. In so doing it leaves the original termination of the peroneal artery connected with the dorsalis pedis to become the arcuate branch of the latter.
The variations of the arteries of the upper extremity may be divided into two categories, A certain number of them, particularly those occurring in the forearm and hand, are directly traceable to the unusual persistence of one or more of the embryonic channels; or, when variation involves magnitude only, to reciprocal variations in the size of the normal vessels. The commoner and more important variations of the arterial distribution, however, arise in a manner much less susceptible to ready explanation. They depend, in fact, upon variations in the course taken by the single or double route which, surviving from the intricacies of the peri-median plexus, persists to maturity. These will be referred to later.
The volar interosseous artery maj' be unusually large. It may reinforce a deficient radia or ulnar through the volar carpal arterj% or its dorsal carpal branch may join the radial at the back of the wrist. In very rare cases the volar interosseous, together with a large ulnar artery, replaces the radial altogether.
A large median artery may participate in the palmar supply of the fingers, either b}' joining the superficial volar arch or (the arch being absent) by breaking directly into digital branches. The median, when large, occasionally replaces the ulnar, verj' rarely the radial, and frequently the superficial volar.
The superficial volar arch may be small, with compensation by the deep, or absent. In the latter case the digital arteries may come directly from the ulnar and radial, ulnar and median or median and radial. In the absence of the superficial volar, which is ver3- frequent, the superficial arch is completed by the princeps pollicis or the volaris radiahs indicis.
Cases are on record in which the ulnar artery, arising in the middle of the arm passes behind the medial epicondyle to follow the nerve in the forearm as usual. The ulnar artery here replaces the superior ulnar collateral and the ulnar recurrent. This anomaly is explained in a striking way by the account given by de Vriese of the development of the vessels of the upper extremity.
Several important variations in the distribution of the main vessels belong to the second category. It is not uncommon for tioo arteries to arise from the primitive peri-median plexus of the arm. In such cases one artery usuaUy takes a course dorsal to the median nerve, i. e., it is crossed medio-lateraUy by the medial head of the nerve and in the contrary direction by the nerve itseh. Its course corresponds to that taken by the ordinary axiUo-brachial trunk; it is known as the deep brachial artery. The other vessel takes a course ventral to the median, nerve, and is known as the superficial brachial. The superficial brachial may join its companion artery, at or above the elbow, or one of the forearm vessels arising from it. In either case the superficial brachial is referred to as a "vas aberrans." Persistence of the superficial brachial further operates as a frequent cause of abnormality in the forearm in that it is often continued directly into one or moi-e of the chief arteries of the latter, the deep brachial taking the remainder. This condition is classified as a high origin of the radial, ulnar, etc., as the case may be.
There is another type of variation belonging to the same category. In this, one large artery only occurs above the elbow which, instead of following the normal course of the brachial, passes, entirely or in part, ventral to the median nerve. In the first case this vessel represents the superficial brachial, the deep being absent. In the second it corresponds in its upper part to the deep brachial and in its lower to the superficial, the two components varying in inverse proportion.
E. MiiUer*, who has made a study of the variations belonging to this category, classifies the abnormal artery occurring in cases of vas aberrans, of high origin of fore arm- vessels, and of single abnormal brachial, according to the proportion of superficial brachial present in any particular example, as a. brachialis superficialis superior media, inferior, or ima. In an embryo of 11.7 milhmetres he found a system of arterial channels in relation with the median nerve out of which any variation of this category might have been produced during further development.
In cases in which the superficial brachial alone persists, the branches of the axillary (and sometimes the profunda brachii and superior ulnar collateral) arise from a common (deep brachial) trunk called the profunda axillaris. In cases in which the deep and superficial brachial co-exist examples of continuation of the superficial brachial into the radial are rather common, continuation into the ulnar less so. Continuation of the superficial brachial into the median, interosseous, or of posterior interosseous arteries occasionally occur, but they are rare. In any case of high origin a cross branch may connect the high vessel with the deep brachial in the neighbourhood of the elbow. The ulnar artery when arising high is often superficial to the forearm flexors (a fact which has not been explained on embryological grounds), the interosseous arising from the radial.
The variations occurring in the arteries of the lower extremity are usually compensatory, or due to persistence of alternative embryonic channels. The sciatic (inferior gluteal) very rarely persists as the main artery of supply. In such cases the small femoral ends as the genu suprema which then appears to be a branch of the profunda.
The profunda is irregular; its origin may occur anywhere between the inguinal Ugament and a point four inches below it. The median or lateral circumflex may arise from the femoral. The branches of the latter commonly arise separately from the profunda, or from the femoral. The popliteal does not vary much in its point of division. High division is commoner than low, but is never higher than the lower epiphyseal fine of the femur.
The anterior tibial may be small and only reach the middle or lower part of the leg. In such cases an enlarged anterior peroneal may end as the dorsahs pedis, or the dorsal metatarsal arteries may be supphed from the plantar arch. Cases in which the anterior peroneal supplies the dorsum of the foot do not represent a dkect inheritance of the embryonic method by which the peroneal artery performs this office. The embryonic route of the peroneal to the dorsum of the foot is transtarsal. The anterior tibial artery may reach the extensor surface of the leg by accompanying the peroneal nerve. This case, hke that of the ulnar artery passing around the medial epicondyle, is interesting in connection with the work of de Vriese. ^ . c ■
The posterior tibial artery may be absent or small, the peroneal replacing it, or remforcmg it by means of the ramus communicans. Absence of the peroneal has been recorded by Otto and W. Krause, but these cases are explained by Barkow as being suppression of the posterior tibial artery between the origin of the peroneal and the communicating branch (Quain).
3. THE SYSTEMIC VEINS
The systemic veins are naturally divided into three groups — (1) the veins of the heart; (2) the vena cava superior and its tributaries, namely the veins of the head, neck, upper extremity, and thorax; and (3) the vena' cava inferior and its tributaries, namely, the portal system, and the veins of the abdomen, pelvis, and lower extremity.
The vena cava superior (fig. 509) carries to the heart the blood returned from the head and neck and upper extremities through the right and left innominate veins, and from the walls of the thorax, either directly through the azygos vein, or indirectly through the innominate veins. It is formed (fig. 509) by the confluence of the right and left innominate veins behind the first right sterno-chondral articulation. Descending from its origin in a gentle curve with its convexity to the right and in a direction slightly backward behind the sternal end of the first and second intercostal spaces and second costal cartilage, it terminates in the right atrium of the heart on a level with the third right costal cartilage in front and the seventh thoracic vertebra behind. It measures about 7 to 8 cm. (3 in.) in length. A little more than its lower half (4 cm.) is contained within the pericardium, the serous layer of that membrane being reflected obliquely over it immediately below the spot where it is joined by the vena azygos, and on a lower level than the reflexion of the pericardium on the aorta. The superior vena cava contains no valves.
Relations. — In front, in addition to the first and second intercostal spaces and the second costal cartilage, it is covered by the remains of the thymus gland, the intrathoracic fascia, and the pericardium, and is overlapped by the right pleura and lung.
Behind (fig. 609) are the vena azygos (major), the right bronchus, the right pulmonary artery, and the superior right pulmonary vein; and below, the fibrous layer of the pericardium. The serous layer is reflected over the front and sides of the vessel, but not over its posterior part.
The innominate or brachio-cephalic veins [vv. anonymae] return the blood from the head and neck and upper extremity. They are formed on each side by the confluence of the internal jugular and subclavian veins behind the sternal end of the clavicle. They terminate behind the first costal cartilage on the right side by uniting to form the vena cava superior. The innominate veins have no valves.
The right innominate vein [v. anonyma dextra] (fig. 509) measures about 2 to 3 cm. (1 to H in-) in length, and descends from its origin behind the sternal end of the clavicle, very slightly forward and medially, along the right side of the subclavian and innominate arteries, to its junction with the left vein behind the first costal cartilage close to the sternum. It is superficial to the innominate artery.
vagus nerve, and the trachea.
The left innominate vein [v. anonyma sinistra] (fig. 509) measures 6 to 7.5 cm. (2| to 3 in.) in length, and extends from its origin behind the sternal end of the left clavicle obHqueljr across the three main branches of the arch of the aorta, to unite with the right innominate vein behind the cartilage of the first rib close to the sternum to form the vena cava superior. In this course it runs from left to right with an inclination downward and slightly backward. A line drawn obliquely across the upper half of the manubrium of the sternum, from the sterno-
clavicular articulation on the left side to the lower border of the first costal cartilage at its junction with the sternum on the right side, will indicate its course. The left innominate vein is on a level with the top of the sternum at birth.
Relations. — In front, in addition to the manubrium of the sternum, it has the origins of the sterno-hyoid and sterno-thyreoid muscles, and the remains of the thymus gland, the sternal end of the left clavicle, and the sterno-clavicular articulation.
Above it are the cervical fascia, the inferior thyreoid, and thyreoidea ima veins.
Tributaries. — In addition to the internal jugular and subclavian veins, by the confluence of which the innominate veins are formed, each vein receives on its upper aspect the vertebral, the deep cervical, and inferior thyreoid veins; and
on its lower aspect the internal mammary vein. The left vein, moreover, is joined by the thyreoidea ima, the left superior intercostal, and by the thymic, tracheal, oesophageal, superior phrenic, anterior mediastinal, and pericardiac veins. At the confluence of the internal jugular and subclavian veins on the right side the three lymphatic trunks or the right lymphatic duct open; on the left side the thoracic duct.
SUPERFICIAL VEINS OF HEAD AND NECK
neck; and the deep, which return the blood from the deeper structures. All the veins, whether superficial or deep, terminate in the internal jugular or subclavian, or open directly into the innominate veins at the root of the neck. Through the latter all the blood from the head and neck ultimately passes on its way to the heart.
The venous blood from the anterior part of the scalp and integument of the face is returned, through the anterior and posterior facial veins, to the common facial, a tributary of the internal jugular vein. From the posterior part of the scalp and from the integument of the neck venous blood is returned, through the external jugular and its tributaries, to the subclavian vein.
supraorbital veins. It descends near the medial angle of the orbit, and then by the side of the nose to the cheek, which it crosses obliquely, to the anterior edge of the massetpr muscle. Thence it passes through the digastric triangle to the upper border of the hyoid bone, where it terminates in the common facial vein. In this course it is reinforced by numerous collateral veins, and gradually increases in size. It has, moreover, numerous communications with the deep veins. The portion of this vein above the lower margin of the orbit is called the angular [v.
The angular vein skirts around the medial margin of the orbit, lying with the angular artery on the frontal (nasal) process of the maxillary bone slightly medial to the lacrimal sac. Branches pass from the posterior part of the angular vein into the orbit to join the ophthalmic.
The angular, the facial, and the ophthalmic veins contain no valves. The blood, therefore, can' pass either forward from the ophthalmic into the angular, or backward through the facial and angular into the ophthalmic, and so on to the cavernous and other venous sinuses of the cranium. Hence in certain tumours in the orbit and cranium, the congestion of the angular and facial veins; and the danger in facial carbuncle and anthrax of septic thrombi spreading backward through the angular and ophthalmic veins to the cranial sinuses.
The anterior facial vein runs in a more or less direct line behind its corresponding artery, the external maxillary (facial), which itself pursues a tortuous course. It usually passes deep to the zygomatic muscle, the zygomatic head of the quadratus labii superioris, and the risorius, but superficial to the other muscles. At the anterior edge of the masseter it meets the external maxillary artery, lying immediately posterior to it. In the neck it lies beneath the platysma and cervical fascia, and is usually separated from the external maxillary artery by the submaxillary gland and the stylo-hyoid and posterior belly of the digastric muscles, below which it is joined by the posterior facial, to form the common facial vein.
Tributaries. — It receives, from above downward: — fa) the frontal vein; (b) the supraorbital vein; (c) the superior palpebral veins; (d) the external nasal veins; (e) the inferior palpebral veins; (f) the superior labial vein; (g) the inferior labial vein; (h) the masseteric veins; (i) the anterior parotid veins; (j) the palatine vein and (k) the submental vein.
(a) The frontal vein [v. frontalis] (fig. 510) begins about the level of the coronal suture in a venous plexus which communicates with the anterior division of the temporal vein. Soon forming a single trunk, it passes vertically downward over the frontal bone, a short distance from the middle line and parallel to its feUow of the opposite side, to the medial end of the eyebrow where it terminates in the angular vein.
(b) The supraorbital vein [v. supraorbitalis] begins over the frontal eminence by intercommunication with the middle temporal vein. It receives tributaries from the forehead and eyebrow, and, running obliquely, medially and downward, opens into the termination of the frontal vein to form the angular. It communicates with the ophthalmic vein, and receives the frontal vein of the diploe as the latter vein issues from the bone at the bottom of the supraorbital notch.
(d) The external nasal veins [vv. nasales externae] form three or four stems on either side. The upper veins run upward into the angular and the lower, from the ala, pass more horizontally into the anterior facial vein.
(e) The inferior palpebral veins [vv. palpebrales inferiores] arise in the lower eyelid, and, passing medially and downward over the cheek from which they receive tributaries, open into the later.ll side of the anterior facial vein. They communicate with the infraorbital vein.
(f) Tlie superior labial vein [v. labialis superior] and (g) the inferior labial vein [v. labialis inferior] arise from venous plexuses in the upper and lower lips. They run laterally to open into the medial side of the facial vein.
(j) The palatine vein [v. palatina] accompanies the ascending palatine or tonsillar artery from the venous plexus about the tonsil and soft palate, and joins the anterior facial vein just below the body of the mandible.
(k) The submental vein [v. submentalis] lies on the mylo-hyoid muscle superficial to the submental artery. Running back in the submental triangle, it joins the anterior facial vein just after the latter has passed over the body of the mandible. It communicates with the anterior jugular vein.
Communications. — The tributaries of the anterior facial vein comrnunicate freely with the anterior and middle temporal, ophthalmic, infraorbital and anterior jugular veins. The main trunk has a large communicating branch with the pterygoid plexus. This vein, sometimes known as the deep facial, opens into the anterior facial Ijelow the zygomatic bone under cover of the zygomaticus muscle.
B. The Posterior Facial Vein
The posterior facial (temporo-maxillary) vein [v. facialis posterior] is formed in in the region of the root of the zygoma by the union of the superficial and middle temporal veins. It passes downward behind the ramus of the mandible
through the substance of the parotid gland— here lying lateral to the superficial temporal and external carotid arteries. At the angle of the mandible it runs medially and somewhat forward, and, passing either deep or superficial to the stylo-hyoid and digastric muscles, joins the anterior facial to form the common facial vein.
temporal veins; (b) the middle temporal vein; (c) the transverse facial vein; (d) the articular veins; fe) the posterior parotid veins; (f) the anterior auricular veins; (g) the stylo-mastoid vein; and (h) the internal maxillary vein through which occurs the principal drainage of the pterygoid plexus.
_ (a) The superficial temporal vein [v. temporalis superficialis] returns the blood from the parietal region of the scalp. It is formed by the union of an anterior and a posterior branch: theformer communicates with the supraorbital and frontal veins; the latter with the posterior auricular and occipital veins and the temporal vein of the opposite side. These branches lie superficial to the corresponding branches of the superficial temporal artery, which they roughly though not accurately follow. Like the artery, they lie between the skin and the cranial aponeurosis, and descend over the temporal fascia to unite a Uttle above the zygoma, and just in front of the auricle of the ear, to form the superficial temporal trunk. The vein thus formed continues its course downward with the trunk of the temporal artery, and opposite the zygoma is joined by the middle temporal vein to form the common temporal vein.
(b) The middle temporal vein [v. temporaUs media] corresponds with the orbital branch of the temporal arterj', and communicates in front with the ophthalmic vein, the external palpebral veins, and the infraorbital veins, and then runs backward between the layers of the temporal fascia to join the superficial temporal vein. The middle temporal vein communicates with the deep temporal veins, and through them with the pterygoid venous plexus.
(c) The transverse facial vein [v. transversa faciei] corresponds to the transverse facial artery, (d) Articular veins [vv. articulares mandibute] form the plexus around the temporomandibular joint; this plexus receives the tympanic veins [w. tympanicae), which, together with its corresponding artery, passes through the petrotympanic fissure, (e) Posterior parotid veins [w. parotidese posteriores] emerge from the substance of the parotid gland, (f) Anterior auricular veins [w. auriculares anteriores], from the auricle of the ear. (g) Stylo-mastoid vein [v. stylomastoidea] from the facial canal, (h) The internal maxallary vein accompanies the first part of the internal maxillary artery. It begins at the posterior confluence of the veins forming the pterygoid plexus, and passes backward between the stylo-mandibular ligament and the neck of the mandible. It ends by joining the posterior facial vein.
The pterygoid plexus [plexus pterygoideus] is formed by the veins which correspond to the branches of the internal maxillary artery. It is situated, partly on the medial surface of the internal pterygoid muscle, and partly around the external pterygoid muscle. The veins entering into this plexus are: — the two middle meningeal veins [w. meningeae mediae], which accompany the artery of that name; the posterior superior alveolar (dental); the inferior alveolar (dental); the masseteric; the buccal; the pterygoid veins from the pterygoid muscles; the deep temporal veins [vv. temporales profundae], by which the plexus communicates with the temporal plexus; the spheno -palatine vein; the infraorbital; the superior palatine; a branch of communication with the lower branch of the ophthalmic vein, which courses through the inferior orbital (spheno-maxillary) fissure; and the rete foraminis ovalis and Vesalian vein, through which the plexus communicates with the cavernous sinus. The plexus ends posteriorly in the internal maxillary vein, which joins the posterior facial vein, and anteriorly in a communicating vessel (the deep facial vein), which passes forward and downward between the buccinator and masseter muscles to join the anterior facial vein.
The above-mentioned veins, forming by their confluence the pterygoid plexus, correspond in then- course so nearly with that of their companion arteries that a detaOed description is not necessary. Although for convenience described with the superficial veins, they are all deeply placed.
Near the angle of the mandible there is almost always a communicating branch between the posterior facial and the external jugular veins. When large, this branch may drain the greater part of the blood from the posterior facial.
The common facial vein [v. facialis communis] is a short thick stem contained within the carotid triangle. It is formed, just below the angle of the mandible, by the union of the anterior and posterior facial veins. It ends opposite the hyoid bone, by opening into the internal jugular vein. In addition to the vessels which form it, sometimes it receives the superior thyreoid, the pharyngeal, and the lingual or the subHngual veins.
D. The External Jugular Vein
The external jugular vein [v. jugularis externa] (fig. 510) is formed by the confluence of the posterior auricular and a short communicating trunlc from the posterior facial near the angle of the mandible. It runs obliquely downward and backward across the sterno-mastoid muscle to a point opposite the middle of the clavicle, where it terminates as a rule in the subclavian vein. A line drawn from a point midway between the mastoid process and angle of the jaw to the middle of the clavicle will indicate its course. It is covered by the skin, superficial fascia, and platysma, and is crossed by a few branches of the cervical plexus, the great auricular nerve running parallel to it at the upper part of the neck. It is separated from the sterno-mastoid by the anterior layer of the deep cervical fascia.
Just above the clavicle it perforates the cervical fascia, by which it is prevented from readily collapsing, the fascia being attached to its walls. It then opens into the subclavian vein, occasionally into the internal jugular, or into the confluence of the subclavian and internal jugular
veins. It contains a pair of valves about 2.5 to 5 cm. (1 to 2 in.) above the clavicle, and a Becond'pair where it enters the subclavian vein. Neither of these valves is sufficient to prevent the blood from regurgitating, or injections from passing from the larger vein into the external jugular.
Tributaries and communications. — These include; — (a) The posterior auricular vein; (b) the occipital vein; (c) a branch of communication with the posterior facial vein; (d) the posterior external jugular vein; (e) the transverse scapular vein; and (f) the anterior jugular vein.
(a) The posterior auricular vein [v. auricularis posterior] begins in a venous plexus on the posterior part of the parietal bone. This plexus communicates with the vein of the opposite side across the sagittal suture, and with the posterior branch of the superficial temporal vein in front, and with the occipital vein behind. It descends over the back part of the parietal bone and the mastoid process of the temporal bone, lying with its artery behind the ear, and joins a branch from the posterior facial vein to form the external jugular.
Common facial vein
(6) The occipital vein [v. occipitalis] begins at the back of the skuU in a venous plexus which anastomoses with the posterior auricular and the posterior branch of the superficial temporal veins. It passes downward over the occipital bone, and usually perforates the trapezius with the occipital artery, to join a plexus drained by the deep crevical and vertebral veins. It also communicates with the posterior auricular, and in many cases this forms the chief path of drainage. One of its branches, usually the most lateral, receives a mastoid emissary vein [emissarium mastoideum] which issues through the mastoid foramen of the temporal bone, and in this way forms a communication with the transverse sinus.
(c) The branch of communication with the posterior facial vein occurs a short distance below the point at which the posterior facial receives the internal maxillary vein. It is very constant and is placed immediately behind the angle of the mandible. Through it the external jugular
goid regions.
(d) The posterior external jugular vein (fig. 512) descends from the upper and back part of the neck, receiving small tributaries from the superficial structures and muscles. At times it communicates with the occipital, or may appear as a continuation of that vein. It opens into the external jugular as the latter vein is leaving the sterno-mastoid muscle.
(e) The transverse scapular vein [v. transversa scapulae] corresponds to the transverse scapular (suprascapular) artery. If double, these venae comitantes usually form one trunk before they open into the external jugular vein. They contain well-marked valves.
(/) The anterior jugular vein [v. jugularis anterior] begins below the chin by communicating with the mental, submental, inferior labial, and inferior hyoid veins. It descends a little lateral to the middle line, receiving branches from the superficial structures at the front and side of the neck, and occasionally a branch from the larynx and thyreoid body. Just above the clavicle it turns laterally, and, piercing the fascia, passes beneath the sterno-mastoid muscle and opens into the external jugular vein just before the latter joins the subclavian; at times it opens into the subclavian vein itself. In its course down the neck it communicates with the external jugular; and, as it turns laterally beneath the sterno-mastoid, sends a branch across the trachea, between the layers of cervical fascia, to join the anterior jugular of the opposite side. This communicating vein, the jugular venous arch [arcus venosus juguli], may open directly into the external jugular or into the internal jugular vein; occasionally one or both ends may open into the subclavian or innominate vein. It may be divided in the operation of tracheotomy, and is then often found greatly engorged with blood. Another branch, often of considerable size, courses along the anterior margin of the sterno-mastoid and joins the anterior facial vein. When the anterior jugular vein is large, the external jugular is small, and vice versa. It is usually also of large size when the corresponding vein on the opposite side is absent, as is frequently the case. It contains no valves.
THE DEEP VEINS OF THE HEAD AND NECK
The deep veins of the head and neck may be divided into: — (1) the veins of the diploe; (2) the venous sinuses of the dura mater encephah; (3) the veins of the brain; (4) the veins of the nasal cavities; (5) the veins of the ear; (6) the veins of the orbit; (7) the veins of the pharynx and larynx; and (8) the deep veins of the neck. The veins of the diploe terminate partly in the superficial veins already described, partly in the venous sinuses of the cranium, and partly in the deep veins of the neck. The venous sinuses open into the deep veins of the neck. The veins of the brain terminate in the venous sinuses. The veins of the nasal cavities terminate partly in the deep, and to some extent in the superficial veins. The veins of the ear join both the superficial and deep veins and the venous sinuses. The veins of the orbit terminate partly in the superficial veins, but chiefly in the venous sinuses. The veins of the pharynx and larynx enter the deep veins of the neck.
1. THE VEINS OF THE DIPLOE
The veins of the diploe [venae diploicse] (fig. 513) are contained in bony channels in the cancellous tissue between the external and internal laminae of the skull. They are of comparatively large size, with very thin and imperfect walls, and form numerous irregular communicating channels. They have no valves. They terminate in four or five main and descending channels, which open, some outward through the external cranial lamina into some of the superficial and deep veins of the head and face, and some inward through the internal lamina into the venous sinuses. They are divided into the frontal, anterior temporal, posterior temporal, and occipital.
The frontal diploic veins are contained in the anterior part of the frontal bone. They converge anteriorly to a single vein [v. diploica frontalis] which passes downward, perforates the external table through a small aperture in the roof of the supraorbital notch, and terminates in the supraorbital vein. They also communicate with the superior sagittal sinus.
The anterior temporal [v. diploica temporahs ant.] are contained in the posterior part of the frontal and in the anterior part of the parietal bone. They pass downward, and end, partly in the deep temporal veins by perforating the greater wing of the sphenoid bone, and partly in the spheno-parietal sinus.
The posterior temporal [v. diploica temporalis post.] ramifies in the parietal bone, and, coursing downward to the posterior inferior angle of that bone, passes either through a foramen in its inner table, or through the mastoid foramen into the transverse sinus.
2. THE VENOUS SINUSES OF THE DURA MATER
The venous sinuses of the dura mater [sinus durse matris] are endothelially lined blood-spaces, situated between the periosteal and meningeal layers of the dura mater. They are the channels by which the blood is conve3red from the cerebral veins, and from some of the veins of the meninges and diploe, into the veins of the neck. The sinuses at the base of the skull also carry the chief part of the blood from the orbit and eyeball to the jugular veins. At certain spots the sinuses communicate with the superficial veins by small vessels known as the emissary veins, which run through foramina in the cranial bones.
The venous sinuses are sixteen in number, six being median and unpaired, the remaining ten consisting of five lateral pairs. The median sinuses are: — (1) the superior sagittal; (2) the inferior sagittal; (.3) the straight; (4) the occipital; (5) the circular; and (6) the basilar plexus. The lateral and paired sinuses are: — • (7) the two transverse; (8) the two superior petrosal; (9) the two inferior petrosal; (10) the two cavernous; and (11) the two spheno-parietal. Occasionally there are two additional sinuses, the two petro-squamous.
(1) The superior sagittal (or longitudinal) sinus [sinus sagittalis superior] (fig. 515) lies in the median groove on the inner surface of the cranium along the attached margin of the falx cerebri. It extends from the foramen caecum to the
temporal diploic
internal occipital protuberance. It grooves from before backward the frontal bone, the contiguous sagittal margins of the parietal bones, and the squamous portion of the occipital bone In the foetus, and occasionally in the adult, it communicates (through the foramen caecum) with the nasal veins. It communicates throughout life with each superficial temporal vein by means of a parietal emissary vein [emissarium parietale] which passes through the parietal foraman. It is triangular on section, the base of the triangle corresponding "to the bone. Crossing it are a number of fibrous bands known as the chords of Willis, and projecting into it in places are the arachnoidal (Pacchionian) granulations. The parts of the sinus into which the arachnoidal granulations project are irregular lateral diverticula from the main channel known as the lacimce laterales ffig. 517). In front the sinus is quite small, but it increases greatly in calibre as it runs backward. It receives at intervals the superior cortical cerebral veins and the veins from the falx. The former, for the most part, open into it in the direction opposite to that in which the blood is flowing in the sinus. They pass for some distance in the walls of the sinus before opening into it. Posteriorly, at the internal occipital protuberance, the superior sagittal sinus usually turns sharply to
Occasionally, however, the superior sagittal sinus ends in the left transverse sinus, the straight then passing into the right. At the angle of union between the superior sagittal sinus and the transverse sinus into which it empties there is a dilation, the confluens sinuum or torcular Herophih. At this point there is a communication between the right and left transverse sinuses. In some cases the communication is so free that the blood from the sagittal sinus flows almost equally into each transverse sinus. The confiuens may communicate with the occipital vein through the occipital emissary vein [emissarium occipitale], which, when present passes through a minute foramen in the occipital protuberance.
(2) The inferior sagittal (or longitudinal) sinus [sinus sagittalis inferior] (fig. 515) is situated at the free margin of the falx cerebri. Beginning about the junction of the anterior with the middle third of the falx, it is continued backward along the concave or lower margin of that process to the junction of the falx with the tentorium, where it ends in the straight sinus. The sinus is cylindrical in
falx. .
(3) The straight sinus [sinus rectus] lies along the junction of the falx cerebri with the tentorium cerebelli. It is formed by the union of the great cerebral vein (of Galen) and the inferior sagittal sinus. It receives in its course branches from the tentorium cerebelh and from the upper surface of the cerebellum. _ It runs downward and backward to the internal occipital protuberance, where it ends in the transverse sinus opposite to that joined by the superior sagittal sinus. On section it is triangular in shape, with its apex upward.
(4) The occipital sinus [sinus occipitaHs] (fig. 514) ascends at the attached margin of the falx cerebelli, along the lower half of the squamous portion of the occipital bone from near the posterior margin of the foramen magnum to the internal occipital protuberance. It usually begins in a right and a left branch, known as the marginal sinuses. These proceed from the termination of each
transverse sinus, run around the foramen magnum, where they communicate with the venous vertebral retia, and unite at a variable distance from the internal occipital protuberance to form the single occipital sinus. Sometimes they remain separate as far as the occipital protuberance, then forming two occipital sinuses. One of the two marginal sinuses may be much smaller than the other, or be entirely absent. At the point where the marginal sinuses unite to form the single occipital sinus, there is a communication with the venous vertebral retia. The occipital sinus ends in the confluens sinuum. It receives in its course veins from the tentorium cerebelli, and from the inferior surface of the cerebellum. It communicates through the plexus of veins which surrounds the hypoglossal nerve [rete canalis hypoglossi] in the hypoglossal (anterior condyloid) canal with the vertebral vein and the longitudinal vertebral venous sinuses.
the median line by means of the anterior and posterior intercavernous sinuses. The intercavernous sinuses are small and cross the median line in front of and behind the hypophysis, respectively.
(6) The basilar plexus [plexus basilaris] is a venous plexus in the substance of the dura mater over the basilar part of the occipital bone. It extends from the cavernous sinus to the margin of the foramen magnum below. It communicates laterally with the inferior petrosal sinus, and inferiorly with the internal vertebral venous plexuses. One of the larger of the irregular venous channels forming the plexus passes transversely from one inferior petrosal sinus to the other. This venous plexus is serially homologous with the longitudinal vertebral venous sinuses on the posterior surfaces of the bodies of the vertebrae.
(7) The transverse (or lateral) sinus [sinus transversus] (figs. 514, 516) extends from the internal occipital protuberance to the jugular foramen. In this course it lies in the groove (which has been named after it) along the squamous portion of the occipital bone, the posterior inferior angle of the parietal bone, the mastoid portion of the temporal bone, and the jugular process of the occipital bone. It at first runs laterally and forward horizontally between the two layers of the tentorium cerebelli, following the curve of the groove on the occipital and on the mastoid angle of the parietal bone. On reaching the groove in the mas-
and ends in the posterior compartment of the jugular fossa in the superior bulb of the internal jugular vein. The S-shaped part of the sinus which hes on the mastoid portion of the temporal and jugular portion of the occipital bone is sometimes known as the sigmoid sinus. The transverse sinus receives the internal auditory veins [vv. auditivse internfe] from the labyrinth, which emerge from the internal auditory meatus. It also receives veins from the temporal lobe of the cerebrum, some of the superior and inferior cerebellar veins, some of the veins of the medulla and pons, the occipital, and the posterior temporal and occipital veins of the diploe. At the point where it leaves the tentorium it drains the superior petrosal sinus and, when present, the petro-squamous sinus. It communicates with the occipital and vertebral veins through the mastoid and posterior condyloid foramina by means of the mastoid and condyloid emissary veins. As the transverse sinus lies between the layers of the tentorium it is on section prismatic in shape. The sigmoid portion is semicylindrical.
The right transverse sinus is usually the larger and the direct continuation of the superior sagittal sinus, and hence conveys the chief part of the blood from the cortical surface of the brain and vault of the skull. The left transverse sinus is usually the smaller and the direct continuation of the straight sinus, and hence returns the chief part of the blood from the central ganglia of the brain. The right and left sinuses communicate opposite the internal occipital protuberance.
The relation of the lateral sinus to the outside of the skuU, especially to the mastoid process of the temporal bone, is of importance with reference to the operations of trephining the mastoid cells, opening the tympanum, and exposing the sinus itself, in septic thrombosis, etc. The course of the sinus corresponds to a hne drawn from the external occipital protuberance to the base of the mastoid process, or to the asterion, and thence over the back of the mastoid process in a curved line toward its apex.
(8) The superior petrosal sinus [sinus petrosus superior] (figs. 514, 515) runs at the attached margin of the tentorium cerebelli, along the upper border of the petrous portion of the temporal bone. It connects the cavernous with the transverse sinus. Leaving the lateral and back part of the cavernous sinus just below the fourth nerve, it crosses the fifth nerve, and, after grooving the petrous bone, ends in the transverse sinus as the latter turns downward on the mastoid portion of the temporal bone. It receives veins from the temporal lobe of the cerebrum, veins from the cerebellum, veins from the tympanum through the squamo-petrosal fissure, and sometimes the anterior temporal veins of the diploe.
(9) The inferior petrosal sinus [sinus petrosus inferior] (figs. 514, 516) runs along the line of the petro-occipital suture, and connects the cavernous sinus with the commencement of the internal jugular vein. It is shorter than the superior petrosal, but considerably wider. As it crosses the anterior compartment of the jugular foramen, it separates the glosso-pharyngeal from the vagus and accessory nerves. It receives veins from the inferior surface of the cerebellum, from the medulla and pons, and from the internal ear. The last, the vein of the cochlear canaliculus [v. canaliculi cochleae], issues through the canaliculus cochleae.
(10) The cavernous sinus [sinus cavernosus] (fig. 516) is an irregularly shaped venous space situated between the meningeal and periosteal layers of the dura mater on the side of the body of the sphenoid bone. It extends from the medial end of the superior orbital (sphenoidal) fissure in front to the apex of the petrous bone behind. Its lateral wall is the more distinct, and contains the third and fourth nerves, and the ophthalmic division of the fifth nerve. The nerves take the above-mentioned order from above downward, and in the medio-lateral direction. The internal carotid artery and the sixth nerve also pass through the sinus, being separated from the blood by the endothelial lining. The right and left cavernous sinuses communicate across the middle line with the opposite sinus in front and behind the hypophysis cerebri as before mentioned.
The cavernous sinus is traversed by numerous trabeculae or fibrous bands, so that there is no central space, but rather a number of endotheUal-lined irregular lacunar cavities communicating one another. Hence its name cavernous, from its resemblance to cavernous tissue. In front it receives the ophthalmic vein, with which it is practically continuous, and just above the third nerve the spheno-parietal sinus. Medially it communicates with the opposite sinus, and posteriorly it ends in the superior and inferior petrosal sinuses. It also receives veins from the inferior surface of the frontal lobe of the brain, and some of the middle cerebral veins. Through the Vesahan vein, which runs in a minute foramen in the spinous process of
the sphenoid bone, the sinus communicates with the pterygoid plexus of veins; through the venous plexus around the petrosal portion of the internal carotid [plexus venosus caroticus internus], with the internal jugular vein; and through a venous rete which leaves the cranium by the foramen ovale [rete foraminis ovalis] and by small veins passing through the foramen lacerum medium, with the pterygoid and pharyngeal plexuses.
(11) The spheno-parietal sinus [sinus sphenoparietalis] runs in a slight groove on the under surface of the lesser wing of the sphenoid bone. It originates in one of the meningeal veins near the apex of the lesser wang, and, running roedially, passes through the sphenoidal fold of dura mater above the third nerve into the front part of the cavernous sinus. It generally receives the anterior temporal veins from the diploe.
._- It hes in a groove along the junction of the petrous and squamous portions of the temporal bone. It opens posteriorly into the transverse sinus at the spot where the latter enters on its sigmoid course. In front it sometimes, though very rarely, passes through a foramen in the squamous portion of the temporal bone between the mandibular fossa and the external auditory meatus into the temporal vein.
The veins of the brain present the following peculiarities: — (a) They do not accompany the cerebral arteries, (h) Ascending veins do not, as in other situations, run with descending arteries, but with ascending arteries, and vice versa. (c) The deep veins do not freely communicate, {d) The veins have very thin walls, no muscular coat, and no valves, ie) The veins opening into the sagittal, and some of those opening into the transverse (lateral) sinus pour in their blood in a direction opposite to the current in the sinuses, so impeding the flow in both
and the central.
The cortical or superficial veins ramify on the surface of the brain and return the blood from the cortical substance into the venous sinuses. The}^ lie for the most part in the sulci between the gyri, but some pass over the gyri from one sulcus to another. They consist of two sets : a superior and an inferior.
(1) The superior cerebral veins [vente cerebri superiores] (fig. 517), some eight to twelve in number on each side, are formed by the union of branches from the convex and medial surfaces of the cerebrum. Those from the convex surface pass medially and forward toward the longitudinal fissure, where they are joined by the branches coming from the medial surface. After receiving a sheath from the arachnoid, they enter obliquely into the superior sagittal
THE CEREBRAL VEINS
sinus, running for some distance in its walls. These veins freely communicate with each other, thus differing from the cortical arteries. They also communicate with the inferior cortical veins. They may be roughly divided into (a) frontal; (6) paracentral; (c) central; (d) occipital. (2) The inferior cerebral veins [venec cerebri inferiores] (fig. 518), ramify on the base of the hemisphere and the lower part of its lateral surface. Those on the inferior surface of the frontal lobe pass, in part into the inferior sagittal sinus, and in part into the cavernous sinus. Those on the temporal lobe enter in part into the superior petrosal sinus, and in part into the transverse sinus, passing into the latter from before backward. A large vein from the occipital lobe winds over the cerebral peduncle and joins the great cerebral vein (of Galen) just before the latter enters the straight sinus. One of the inferior cortical veins is called the middle cerebral vein [v. cerebri media] ; it runs in the lateral fissure (of Sylvius) and ends in the cavernous sinus. This vein is sometimes called the superficial Sylvian vein. Another, the great anasto-
Occipital sinus
mosing vein of Trolard, a branch of the middle cerebral, estabhshes a communication between the superior sagittal and cavernous sinuses by anastomosing with one of the superior cortical veins. A second anastomotic vein, that of Labb6, is also a tributary of the middle cerebral, and connects the veins over the temporal lobe with the transverse sinus.
A small inferior cerebral vein, the ophthalmomeningeal vein, estabhshes a communication between the cerebral veins and those of the orbit. It communicates with the veins of the base and is usually drained by the superior ophthalmic vein. It occasionally opens into the superior petrosal sinus.
Fig. 519. — The Veins of the Brain, Lateral Surface. (After Toldt, "Atlas of Human Anatomy/' London and New York.) — The Ophthalmic Veins. (After Quain.)
(3) The internal cerebral veins [vv. cerebri internee] are two large venous trunks (the vense Galeni) which leave the brain at the transverse fissure, that is, between the splenium of the corpus callosum and the corpora quadrigemina. In this region they unite to form the great cerebral vein [v. cerebri magna, Galeni], which opens into the anterior end of the straight sinus. The internal cerebral veins are formed by the union of the chorioid vein with the vena terminalis near the interventricular foramen. From this spot they run backward parallel to each other, between the layers of the tela chorioidea, and terminate in the way above mentioned.
Tributaries of the internal cerebral veins. — In addition to the vena terminalis and the chorioidal, the internal cerebral veins also receive the basal vein, the veins of the thalmus, the vein of the chorioid plexus of the third ventricle, and veins from the corpus callosum, the pineal body, the corpora quadrigemina, and posterior horn of the lateral ventricle. The united trunk, or great cerebral vein, receives veins from the upper surface of the cerebellum, and one of the posterior inferior cerebral veins.
The chorioid vein [v. chorioidea] runs with the chorioid plexus. It begins in the inferior cornu of the lateral ventricle, and ascends on the lateral side of the chorioid plexus along the margin of the tela chorioidea to the interventricular foramen, where it unites with the vena terminalis to form the internal cerebral vein. It receives tributaries from the hippocampus, corpus callosum, and fornix.
The terminal vein (or vein of the corpus striatum) [v. terminalis], formed by veins from the corpus striatum and thalamus, runs forward in the groove between those structures, passing in its course beneath the stria terminalis, and joins the chorioid (choroid) vein at the interventricular foramen. Tributaries. — It receives, in addition to the veins from the corpus striatum, thalamus and fornix, the vena septi pellucidi which receives blood from the septum peUucidum, and anterior cornu of the lateral ventricle.
internal cerebral vein near the union of that vessel with the vein of the opposite side.
Tributaries. — A vein, the deep Sylvian, from the insula and surrounding convlutions; the inferior striate veins from the corpus striatum, which they leave through the anterior perforated substance; and the anterior cerebral veins from the front of the corpus callosum. It is also joined by interpenduncular veins from the structures in the interpeduncular space; ventricular veins from the inferior cornu of the lateral ventricle; and by mesencephalic veins from the mid-brain.
The cerebellar veins are divided into the superior and inferior.
The superior [vv. cerebeDi superiores] ramify on the upper surface of the cerebellum; some of them run medially over the superior vermis to join the straight sinus and great cerebral vein; others run laterally to the transverse and superior petrosal sinuses.
The venous plexuses on the inferior nasal concha (turbinate bone) and back of the septum are described with the Nose. The veins leaving the nasal cavities follow roughly the course of their corresponding arteries. Thus the sphenopalatine veins pass through the spheno-palatine foramen into the pterygoid plexus; the anterior and posterior ethmoidal veins join the ophthalmic. Small veins accompany branches of the external maxillary artery through the nasal bones and frontal processes of the maxillary bones, and end in the angular and anterior facial veins; and other small veins pass from the nose anteriorly into the superior labial, and thence to the anterior facial.
The veins from the external ear and external auditory meatus join the posterior facial and posterior auricular veins. The veins from the tympanum open into the superior petrosal sinus and posterior facial vein. The blood from the labyrinth flows chiefly through the internal auditory veins [vv. auditivse internse], which lie with the internal auditory artery in the internal auditory meatus, and enters the transverse or inferior petrosal sinus. Some of the blood from the labyrinth, however, passes through the vestibular vein which Hes in the aquseductus
vestibuli, into the inferior petrosal sinus. Some also passes through the vena canalicuU cochleae which traverses the canal of the same name and empties into the commencement of the internal jugular vein.
The blood from the eyeball and orbit is returned by the superior ophthalmic vein into the cavernous sinus. This vein and its tributaries have no valves, and communicate with the frontal, supraorbital, inferior cerebral, and other veins. Hence under certain conditions, as from pressure on the cavernous sinus, the blood
may flow in the contrary direction to the normal — i. e., from behind forward into the frontal and supraorbital, and thence through the angular vein into the anterior facial; or upward into the cerebral venous system. In this way pressure on the retinal veins is quickly relieved, and little or no distension occurs in cases of obstruction in the cavernous sinus.
The superior ophthalmic vein [v. ophthalmica superior] begins at the medial angle of the eyelid by a free communication with the frontal, supraorbital, and angular veins, and thence runs backward and laterally with the ophthalmic artery across the optic nerve to the medial end of the superior orbital (sphenoidal) fissure, where it is usually joined by the inferior ophthalmic vein. It then passes backward between the two heads of the lateral rectus muscle below the sixth nerve, leaves the orbit through the medial end of the superior orbital (sphenoidal) fissure and enters the front part of the cavernous sinus. In this course it lies anterior and superficial to the ophthalmic artery.
Tributaries. — (1) The naso-frontal vein; (2) the superior muscular veins; (3) the veins of the lids and conjunctiva; (4) the ciliary veins; (5) the anterior and posterior ethmoidal veins; (6) the lacrimal vein; (7) the central vein of the retina; and (8) the inferior ophthalmic vein.
(1) The naso-frontal vein [v. naso-frontalis] begins by a free communication with the supraorbital vein and enters the orbit through the frontal notch or foramen. It frequently joins the superior ophthalmic vein quite far back in the orbit (see fig. ,520).
into the muscular veins returning the blood from the four recti. They form a circumcorneal ring of episcleral veins [w. episclerales]. The posterior set, which drain the venae vorticosae, leave the globe midway between the cornea and the entrance of the optic nerve. The latter veins are four or five m number, the upper ending in the superior, the lower in the inferior ophthalmic vein (fig. 520).
(5) The anterior and posterior ethmoidal veins [w. ethmoidales ant. et post.), correspond in their course with the arteries of the same name. They enter the orbit through the anterior and posterior ethmoidal foramina, and join either the ophthalmic direct, or one or other of the superior muscular branches.
optic nerve. It joins the superior ophthalmic at the back of the orbit.
(8) The inferior ophthalmic vein [v. ophthalmica inferior], smaller than the superior, is formed near the front of the orbit by the confluence of the inferior muscular with the lower posterior ciliary veins. It runs backward below the optic nerve, along the floor of the orbit, and either joins the superior ophthalmic vein, or opens separately into the cavernous sinus. A large communicating branch passes downward through the inferior orbital (spheno-maxillary) fissure to join the pterygoid plexus of veins. It receives muscular twigs from the inferior and lateral rectus and from the interior oblique, and some posteior ciliary veins.
7. THE VEINS OF THE PHARYNX AND LARYNX
The pharyngeal veins [vv. pharyngeee] are arranged in the form of a plexus, between the constrictor muscles and the pharyngeal or prevertebral fascia. The pharyngeal plexus receives branches from the mucous membrane, the pterygoid canal [vv. canalis pterygoidei] from the soft palate, the Eustachian tube and the anterior recti and longus colli muscles. Above, it communicates with the pterygoid plexus of veins; below it drains into the internal jugular vein.
The veins of the larynx end partly in the superior laryngeal vein [v. laryngea superior], which opens into the internal jugular vein, and partly in the inferior laryngeal vein [v. laryngea inferior], which terminates in the plexus thyroideus impar. The laryngeal plexus of veins communicates with the pharyngeal plexus.
The internal jugular vein [v. jugularis interna] begins at the jugular fossa, and is the continuation of the transverse sinus. It passes down the neck, in company first with the internal carotid artery and then with the common carotid artery, to a point a little lateral to the sterno-clavicular articulation, where it joins the subclavian to form the innominate vein. At its commencement in the larger, posterior and lateral part of the jugular foramen, it is somewhat dilated, forming the superior bulb of the jugular vein [bulbus v. jugularis superior] (fig. 522). This dilated part of the internal jugular vein lies in the jugular fossa of the temporal bone and is therefore in immediate relation to the floor of the tympanum. At first the internal jugular lies in front of the rectus capitis lateralis, and behind the internal carotid artery, from which it is separated by the hypoglossal, glossopharyngeal, and vagus nerves, and by the carotid plexus of the sympathetic. As it descends it passes gradually to the lateral side of the internal carotid, and retains this relation as far as the upper border of the thyreoid cartilage. Thence it runs to its termination along the lateral side of the common carotid artery, being contained in the same sheath with it and the vagus nerve, but separated from these structures by a distinct septum. The vein generally overlaps the artery in front. About 2.5 cm. (1 in.) above its termination it contains a pair of imperfect valves below which a second dilation usually occurs in the vein. This, the inferior bulb [bulbus v. jugularis inferior], extends as low as the junction of the internal jugular with the subclavian. It not infrequently receives the termination of the external jugular vein.
vein; opposite the angle of the jaw, veins from the pharyngeal plexus, and often a communicating branch from the external jugular vein; opposite the bifurcation of the carotid it is joined by the common facial, and a little lower down by the lingual, sternomastoid, and the superior thyreoid veins. At the level of the cricoid cartilage by the middle thyreoid when this vein is present.
The inferior petrosal sinus is described with the other sinuses of the brain (p. 652) ; the pharyngeal plexus with the veins of the pharynx (see p. 659) ; and the common facial vein with the superficial veins of the scalp and face (p. 646).
The lingual vein [v. lingualis], begins near the tip of the tongue, where it accompanies the arteria profunda linguEe. It lies at first beneath the mucous membrane covering the under surface of the tongue. It then passes backward medial to the hyo-glossus, and in company with the lingual artery. After receiving the sublingual vein [v. sublingualis] and the dorsal
lingual veins [w. dorsales linguae], which roughly correspond to their respective arteries, it is joined by the small v. comitans nervi hypoglossi which follows the upper border of the hypoglossal nerve. The trunk finally crosses the common carotid artery and opens into the internal jugular vein. The lingual vein communicates with the pharyngeal veins and with tributariesof the anterior facial. It occasionally terminates in the posterior or in the common facial vein. The sternomastoid vein [v. sternocleidomastoidea] accompanies the artery of the same name and empties into the internal jugular.
The superior thyreoid vein [v. thyreoidea superior] emerges from the upper part of the thyreoid gland, in which it freely anastomoses with the other thyreoid veins. This anastomosis, the plexus thyreoideus impar, occurs both in the substance of the organ and on its surface beneath the capsule. The vein then passes upward and laterally into the interna] jugular vein, crossing the common carotid artery in its course. At times it forms a common trunk with the common facial vein. Its tributaries are the sterno-hyoid, sterno-thyreoid, and thyreo-hyoid veins from the muscles bearing those names; and the crico-thyreoid and superior laryngeal veins which correspond with the crico-thyreoid and superior laryngeal arteries respectively. These require no special description.
A separate vein frequently passes out from the capsule of the thyreoid gland near the lower part of the lateral lobe, crosses the common carotid, and opens into the main superior thyreoid vein or into the internal jugular vein a little below the cricoid cartilage. In the former case it is regarded as part of the superior th3Teoid vein system ; in the latter it is generally known as the middle, thyreoid vein.
The vertebral vein [v. vertebralis] does not accompany the vertebral artery in its fourth stage, that is, within the skull, but begins in the posterior vertebral venous plexus of the suboccipital triangle. It then enters the foramen in the transverse process of the altas, and passes with the vertebral artery through the foramina in the transverse processes of the cervical vertebrae, forming a plexus around the artery. On leaving the transverse process of the sixth cervical vertebra it crosses in front of the subclavian artery and opens into the innominate vein. It has one or two semilunar valves at its entrance into the innominate vein. In the suboccipital triangle it communicates with the internal vertebral venous plexuses, with the deep cervical, and occipital veins, and is joined by veins from the recti and oblique muscles and the pericranium.
Tributaries. — -As it passes down the neck it receives (1) intervertebral veins, which issue along with the cervical nerves, from the spinal canal; (2) tributaries from the anterior and posterior vertebral venous plexus from the bodies of the cervical vertebrse and their transverse processes; and (3) tributaries from the deep cervical muscles. Just before it terminates in the innominate it is joined by (4) the anterior vertebral vein, a small vein which accompanies the ascending cervical artery, and, sometimes, by the deep cervical vein.
The deep cervical vein [v. cervicahs profunda], larger than the vertebral, passes down the neck posterior to the cervical transverse processes. It corresponds to the deep cervical artery from which it is separated by the semispinalis eervicis muscle.
It begins in the posterior vertebral venous plexus and receives tributaries from the deep muscles of the neck. It communicates with, or enthely drains, the occipital vein by a branch which perforates the trapezius muscle. The deep cervical vein then passes forward beneath the transverse process of the seventh cervical vertebra to open into the innominate vein near the vertebral, or into the latter near its termination. Its orifice is guarded by a pair of valves.
The inferior thyreoid veins [vv. thyreoidea inferiores] descend from the lower part of the thyreoid gland obliquely lateralward to the innominate veins. The right vein crosses the innominate arteiy just before its bifurcation, and ends in the right innominate vein a little above the superior vena cava. It receives inferior laryngeal veins and veins from the trachea, and has valves at its termination in the innominate. The left vein passes obliquely over the trachea behind the sterno-thyreoid muscle, and opens into the left innominate vein. It also receives laryngeal and tracheal veins, and sometimes the thyreoidea ima; it is guarded by valves where it opens into the innominate trunk.
The thyreoidea ima vein [v. thyreoidea ima] is single and placed approximately in the median line. It begins in the thj'reoid isthmus from the plexus thyreoideus impar, runs downward upon the anterior surface of the trachea, and opens into the left innominate vein or into the left inferior thja-eoid.
The Thymic, Tracheal and CEsophageal Veins
These small veins usually open into the left innominate vein. The thymic veins [vv. thymicae], small in the adult, open into the left innominate or into the inferior thyreoid or thyreoidea ima vein. The tracheal veins [vv. tracheales] anastomose with the laryngeal and bronchial veins. The oesophageal veins [vv. cesophagese] from the upper part of the oesophagus, anastomose with the lower oesophageal veins and with the pharyngeal plexus.
The superficial veins of the front of the thorax can be seen in fig. 537. They form a plexus over the entire chest which the portion over the mammary gland is called the mammary plexus. The laterally placed lateral thoracic and costoaxillary veins drain the mammary plexus and communicate with the thoracoepigastric vein. These three veins terminate in the axillary vein (p. 671). The veins nearer the median line are drained by the internal mammary vein and its anterior intercostal and superior epigastric tributaries. The veins over the entire thorax are in free communication with the superficial veins of the abdominal wall (p. 683).
The deep veins of the thorax are: — the pulmonary veins, and the vena cava superior and its innominate and other tributaries. Of these veins, the pulmonary, the vena cava superior, and the innominate veins have already been described, as have the tributaries of the latter arising in the neck.
The following veins are described below: — (1) The azygos and ascending lumbar veins, which discharge their blood into the vena cava superior; (2) the veins of the vertebral column, which are tributary to the azygos veins through the intercostals; (3) the internal mammary veins, and (4) the superior phrenic, anterior mediastinal and pericardiac veins, all of which open into the innominate veins.
I. THE AZYGOS AND ASCENDING LUMBAR VEINS
The azygos veins are longitudinal veins, the remnants of the posterior cardinals, which are the main collecting trunks for the posterior part of the body in the embryo. They lie along the sides of the thoracic vertebrae, and collect the blood from the intercostal veins; they are the upward continuation of longitudinal anastomotic trunks, the ascending lumbar veins which take origin in the abdomen. The azygos veins are three in number, the azygos (azygos major) on the right side, and the hemiazygos (azygos minor) and accessory hemiazygos (azygos tertia) on the left.
The azygos vein [v. azygos] begins in the abdomen as a continuation .upward of the ascending lumbar vein. Through this means it connects with the iliac veins and it has also an anastomosis with the vena cava inferior which may become very important in cases of obstruction of the vena cava. It runs up through the posterior mediastinum on the right side of the front of the bodies of the thoracic vertebrte as high as the fourth thoracic vertebra, in this part of its course lying to the right of the aorta and thoracic duct; it then curves forward over the root of the right lung, and opens into the vena cava superior immediately before the latter pierces the pericardium.
It usually contains an imperfect pair of valves at the point where it turns forward from the fourth thoracic vertebra to arch over the root of the lung; and still more imperfect valves are found at varying intervals lower down the vein.
It receives the intercostal veins of the right side, except the first two or three. These veins (usually excepting the first) are collected into a common trunk before joining the azygos vein. It also receives the hemiazygos and accessory hemiazygos, the right posterior bronchial vein, and small oesophageal and posterior mediastinal veins.
The hemiazygos vein [v. hemiazygos] begins in the abdomen by communicating, like the azygos vein, with the ascending lumbar vein of its own side. It courses up the posterior mediastinum to the left of the bodies of the lower thoracic vertebrae as high as the eighth or ninth, where it turns obliquely to the right, and, crossing in front of the vertebral column behind the aorta and the oesophagus, opens into the vena azygos. In its course it crosses over three or four of the lower left intercostal arteries, and is covered by the pleura.
Tributaries. — (1) The lower four or five left intercostal veins; (2) the lower end of the accessory hemiazygos vein (sometimes); (3) small left mediastinal veins; and (4) the lower left oesophageal veins.
The accessory hemiazygos [v. azygos accessorial varies considerably in size, position, and arrangement, and is often continuous with, or drained by, the left superior intercostal vein. It hes in the posterior mediastinum by the left side of the bodies of the fifth, sixth, and seventh or eighth thoracic vertebrae, and is more
Left ascending lumbar
or less vertical in direction. It communicates above with the left superior intercostal vein, and below either joins the hemiazygos or passes obliquely across the seventh or eighth thoracic vertebra to join the azygos vein. It crosses the corresponding left intercostal arteries, and is covered by the pleura.
means of the anterior sacral plexus, with the middle and lateral sacral veins, and with the common iliac, hypogastric and ilio-lumbar veins. It ascends in front of the lumbar transverse processes communicating with the lumbar veins, the vena cava inferior and, usually, with the renal vein. The right vein enters the thorax between the aorta and the right medial crus of the diaphragm, and is continued upward as the vena azygos. The left vein pierces the left medial crus and becomes the hemiazygos.
The intercostal veins [vv. intercostales]. — The intercostal veins are twelve in number on each side, the last one being subcostal. They correspond to the intercostal arteries. There is one vein to each artery, the vein lying above the artery whilst in the intercostal space. Each vein receives a dorsal tributary which accompanies the posterior ramus of an intercostal artery between the transverse process of the vertebrae and the neck of the rib. These dorsal branches not only return the blood from the muscles of the back, but receive a spinal branch from the vertebral venous plexuses. The intercostal veins also receive small tributaries from the bodies of the vertebrae. The termination of the intercostal veins is different on the two sides and also varies greatly in different individuals. The intercostal vein from the first space on either side may join the superior intercostal vein, but commonly opens directly into the innominate or one of its tributaries, most frequently the vertebral.
On the right side. — The second intercostal vein joins with the third or with the third and fourth to form the right superior intercostal vein [v. intercostalis suprema dextra]. This vein opens into the azygos vein as the latter is arching over the root of the right lung. The rest join the azygos directly. The upper of these liave well-marked valves where they join the azygos vein; in the lower veins these valves are imperfect. All the intercostal veins are provided with valves in their course between the muscles.
On the left side the second intercostal vein joins the third and fourth to form a single trunk, the left superior intercostal vein [v. intercostalis suprema sinistra]. This vein passes upward across the arch of the aorta and opens into the left innominate vein. The left superior intercostal frequently communicates at its lower end with the accessory hemiazygos vein, which is occasionally tributary to it. In most oases a small tributary runs up over the front of the aortic arch to join the superior intercostal vein; it is a vestige of the left common cardinal and from it a small fibrous cord can often be traced through the vestigial fold of the pericardium to the oblique vein of the left atrium (p. 523).
The left fifth, sixth and seventh intercostal veins commonly open into the accessory hemiazygos, and the eighth or ninth and succeeding veins into the hemiazygos. The method of termination of the intercostal veins of the left side is subject to such variation that a normal arrangement can scarcely be said to exist at all. The eighth may open directly into the azygos, as may the seventh and ninth or even more of the veins; the hemiazygos and accessory hemiazygos being correspondingly reduced in size.
The posterior bronchial veins [vv. bronchiales posteriores] correspond to the bronchial arteries, but do not return the whole of the blood carried to the lungs by those vessels — that part which is distributed to the smaller bronchial tubes and the alveola; being brought back by the pulmonary veins. The posterior bronchial veins issue from the lung substance behind the structures forming the root of the lung. The right vein generally joins the vena azygos just before the latter vein enters the superior vena cava. The left vein opens into accessory hemiazygos vein. The bronchial veins at the root of the lung receive smaU tributaries from the bronchial glands, from the trachea, and from the posterior mediastinum.
The oesophageal veins [vv. oesophagefe] from the thoracic portion of the oesophagus end in part in the vena azygos, and in part in the vena hemiazygos. They anastomose with the upper oesophageal veins, and with the coronary vein.
2. THE VEINS OF THE VERTEBRAL COLUMN
The venous plexuses around and within the vertebral column extending from the cranium to the coccyx may be divided into two categories: — (1) the external and (2) the internal vertebral venous plexuses. The external plexuses consist of two parts, the anterior vertebral venous plexuses situated on the anterior aspect of the vertebral bodies and the posterior vertebral venous plexuses ramifying over the posterior aspect of the vertebral arches, spines, and transverse processes. The internal plexuses consist of two longitudinal venous sinuses situated between the vertebrae and the posterior longitudinal ligament, and of two vertebral venous retia placed immediately external to the dura mater. The sinuses of the internal plexuses communicate freely with one another and with the internal retia and external plexuses. They receive the external spinal veins and the basivertebral veins from the bodies of the vertebrae. The venous circulation of the vertebral
following :
(a) The anterior vertebral venous plexuses [plexus venosi vertebrales anteriores] (fig. 524) consist of small veins ramifying in front of the bodies of the vertebrae. These veins communicate with the basivertebral veins and are larger in the cervical region than elsewhere.
(6) The posterior vertebral venous plexuses [plexus venosi vertebrales posteriores] (fig. 524) are situated around the transverse, articular, spinous processes and laminae of the vertebrae. Communications take place between the plexuses of each segment and with the veins of the neighbouring muscles and integuments. Branches are also sent, through the ligamenta flava, to the internal vertebral venous plexuses, and, between the transverse processes, to the intervertebral veins.
2. The internal vertebral venous plexuses [plexus venosi vertebrales interni] (fig. 524) : — (a) The two longitudinal vertebral sinuses [sinus vertebrales longitudinales] run throughout the entire length of the vertebral canal. They are situated behind the bodies of the vertebrae on either side, between the bone and the posterior longitudinal hgament. The sinuses have
ertebral plexu
extremely thin walls, and their interior is made irregular by numerous folds but no true valves are present. The calibre of the longitudinal sinuses is reduced by constrictions opposite the intervertebral discs; the consti'ictions alternating with dilatations opposite the vertebral bodies. At each dilatation there occurs a cross communication between the longitudinal sinuses of either side, and each receives a basivertebral vein from the corresponding vertebral body. Opposite every intervertebral foramen and anterior sacral foramen each longitudinal sinus is joined by the corresponding intervertebral vein. The longitudinal sinuses communicate very freely with one another, and with the vertebral retia. At the foramen magnum they communicate with the basilar plexus and, by means of the rate canalis hypoglossi, with the internal jugular vein.
(6) The venous rete of the vertebrae [retia venosa vertebrarum] (fig. 524) extend from the foramen magnum to the coccyx. They consist of two main retia situated posteriorly and lateraOy to the dura between the latter and the vertebral arch. They communicate very freely with one another across the median line; with the posterior external plexus by means of twigs perforating the ligamenta flava; and with the longitudinal vertebral sinuses by means of lateral branches. At the foramen magnum they communicate with the occipital sinus.
{d) The basivertebral veins [vv. basivertebrales] (fig. 524) collect the blood from the cancellous tissue of the bodies of the vertebra;, and consist of a tunica intima only. They take a radial direction converging to the transverse vessels connecting the longitudinal vertebral sinuses. They communicate with the anterior external plexus and with the intercostal veins.
Dura mater spinalis
sinus and pass out through the intervertebral or anterior sacral foramina. They open into the vertebral, intercostal, lumbar or sacral veins according to region and receive numerous tributaries from the anterior and posterior external vertebral venous plexuses. They are instrumental in draining the venous system of the vertebral column and spinal cord.
The internal mammary vein [v. mammaria interna] is formed by the union of the vena3 comitantes corresponding to the superior epigastric and musculo-phrenic arteries. The right and left internal mammary veins pass upward, in company with the corresponding arteries, to open into the right and left innominate respectively.
PERICARDIAC VEINS
The superior phrenic [vv. phreniese superiores], the anterior mediastinal [w mediastinales anteriores], and pericardiac [w. pericardiacae] veins are small vessels, corresponding to the arteries of those names. They pass over the arch of the aorta and open into the lower and anterior part of the left innominate.
The superficial veins ramify in the subcutaneous tissue above the deep fascia, and they do not accompany arteries. The deep veins accompany the arteries, and have practically the same relations as those vessels. The superficial and deep veins communicate at frequent intervals through the intermuscular veins which run between the muscles and perforate the deep fascia. Both sets of veins are provided with valves, but the valves are more numerous in the deep than in the superficial. There are usually valves where the deep veins join the superficial. The superficial veins are larger than the deep, and take the greater share in returning the blood.
I. THE SUPERFICIAL VEINS OF THE UPPER EXTREMITY
The superficial veins begin in two irregular plexuses, one in the palm and the other on the back of the hand. The plexus in the palm is much finer, and communicates with the superficial volar veins of the fingers. The latter discharge their blood into the dorsal venous rete by means of the veins of the folds between the fingers, or the intercapitular veins [vv. intercapitulares] (fig. 426).
The veins of the back of the hand begin in a longitudinal plexus over the fingers, and at the bases of the fingers the veins of the adjacent digits are connected by digital venous arches [arcus venosi digitales], from which arise the dorsal metacarpal veins [vv. metacarpese dorsales]; these form upon the back of the hand a dorsal venous rete [rete venosum dorsale manus] (fig. 427).
Of the veins of the arm, two stand out prominently, the basilic and the cephalic. Both of these arise from the veins of the back of the hand, curve around to the volar surface of the forearm, and pass to the upper arm (fig. 426).
The basilic vein [v. basilica],* arises on the back of the hand from the ulnar end of the dorsal venous rete, which usually forms an arch. It curves around the ulnar side of the forearm to the volar surface and passes to the elbow and the upper arm, where it lies in the median bicipital sulcus. It extends up to about the middle third of the sulcus, and, piercing the brachial fascia, joins the brachial vein.
The cephalic vein [v. cephalica],* begins at the radial end of the dorsal venous rete or arch and curves around the radial border of the forearm to the volar surface not far above the thumb. It passes to the elbow and the upper arm, but, unlike the basilic, it maintains its superficial course up to the shoulder, lying first in the lateral bicipital sulcus and then in the groove between the pectoralis major and the deltoid. Just below the clavicle it turns into the depth, and empties into the axillary vein.
In the forearm plexus one or more longitudinal veins besides these are usually distinct. One lateral to the cephalic is known as the accessory cephalic [v. cephalica accessoria] (formerly the radial) vein; one near the centre is known as the median antibrachial [v. mediana antibrachii], (formerly the anterior ulnar) vein.
*Tlie basilic vein here described corresponds to tlie posterior ulnar and basilic; the cephalic corresponds to the median, median cephalic and cephalic of the older terminology employed in English text-books. The BNA terminology has the gi-eat advantage that it can be readily used to desci'ibed any form of venous pattern. The English terminology applies only to cases in which the M-shaped arrangement occurs upon the volar surface of the elbow. Berry and Newton find the latter arrangement in only 13 per cent, out of 300 cases examined.
Note. — In the limb here represented the direct venous channel on the radial side of the forearm, the accessory cephalic (formerly radial) vein, is continued directly into the cephalic above the elbow. The cephalic in the forearm (formerly median) is mainly drained by the basilic through the median antecubital. The vein opposite the bend of the elbow, which usually forms the segment of the cephalic formerly known as the median cephalic vein, is here a small channel draining into an accessory median cubital. The basilic vein of the forearm (formerly posterior ulnar) is represented by a plexus of small venous channels.
median basilic. Occasionally the cephalic in the upper arm is reduced to a small tributary, which takes the course of the cephalic in the forearm, but bends ulnarward at the elbow to form the basilic. Numerous connections occur between the deep and the superficial veins at the elbow.
Beginning at the fingers, two minute proper volar digital veins [venae digitales volares proprise], accompany each digital artery along the sides of the fingers, and uniting at the cleft, form common volar digital veins [vv. digitales volares communes], which join the vense comitantes of the arteries, forming the superficial palmar arch. In like manner the veins accompanying the arteries forming the deep arch receive tributaries, the volar metacarpal veins [vv. metacarpese volares], corresponding to the branches of that arch. A superficial and a deep volar venous arch [ arcus volaris venosi superficialis et profundus] are thus formed accompanying the arterial arches. The venae comitantes from the ulnar side of the superficial and deep arches unite at the spot where the ulnar artery divides into the superficial and deep branch to form two ulniar venae comitantes [vv. ulnares] ; whilst those on the radial side of the superficial and deep arch accompan}^ the superficial volar artery and the termination of the radial artery respectively, and unite at the spot where the superficial volar is given off from the radial artery, to form the radial venae comitantes [vv. radiales]. The ulnar and radial venae comitantes thus formed course up the forearm with their respective arteries, receiving numerous tributaries from the muscles amongst which they run, and giving frequent communications to the superficial veins. They finally unite at the bend of the elbow to form the brachial venas comitantes [vv. brachiales]. The ulnar venae comitantes receive, before joining the radial, the companion veins of the interosseous arteries. At the bend of the elbow the deep veins are connected with the basilic or with the median antibrachial vein by a short, thick trunk (fig. 528).
The brachial venae comitantes accompany the brachial artery. At the lower border of either the teres major or subscapularis muscle, the more medial vein receives the more lateral and the basilic vein, to form a single axillary vein.
by frequent cross branches.
The axillary vein [v. axillaris], is formed by the junction of the medial brachial vena comitans with the basilic vein at the lower border of either the teres major or subscapularis muscle. It is a vessel of large size, conveying as it does nearly the whole of the returned blood from the upper extremity. It accompanies the axillary artery through the axillary fossa, lying to its medial side and, at the upper part of the space, on a slightly posterior plane. At the lateral border of the first rib it changes its name to the subclavian. It has one or two axillary lymphatic nodes in close connection with it, and is liable, if care is not taken, to be wounded in removing these glands. The vein contains a pair of valves, usually placed near the lower border of the subscapularis muscle.
Tributaries : — (1) The subscapular veins which accompany the subscapular artery; (2) the circumflex veins accompanying the circumflex arteries; (3) the lateral thoracic vein [v. thoracalis lateralis] a large vein which accompanies the lateral thoracic artery and receives numerous thoraco-epigastric veins [vv. thoracoepigastricse] from the epigastric and lower thoracic regions; (4) the costoaxillary veins [vv. costoaxillares] the radicles of which arise in the pectoral region from the mammary plexus [plexus venosus mamillae] ; and (5) the cephalic vein.
The subclavian vein [v. subclavii] (fig. 528), is the continuation of the axillary. It begins at the lateral border of the first rib, and terminates by joining the internal jugular to form the innominate vein opposite the lateral end of the sterno-clavicular articulation. It lies anterior to the subclavian artery and on a lower plane, and is separated from the artery in the second part of its course by the scalenus anterior muscle. The subclavian vein, just before it is joined by the external jugular, contains a pair of valves.
Tributaries. — The subclavian vein receives the thoracoacromial vein near its distal end, and the external jugular vein near the lateral border of the sternomastoid muscle. The transverse cervical veins terminate in the subclavian near the external jugular, or in the latter vein, or in a plexiform arrangement formed between the transverse scapular, transverse cervical and external jugular veins. The external jugular vein is described with the superficial veins of the head and neck (p. 646).
The thoracoacromial vein [v. thoracoacromiahs], receiving tributaries corresponding to the branches of the artery of the same name, terminates near the lateral border of the first rib.
The transverse cervical veins [vv. transversae colli] receive tributaries corresponding in distribution to the branches of the transverse cervical artery. They emerge from beneath the trapezius muscle, cross the posterior triangle, and usually terminate in the subclavian vein. They usually terminate as a single vein the orifice of which is guarded by a pair of valves. Occasionally the cephahc vein, or a branch from the cephalic (the jugulo-cephalic), passes over the clavicle to the subclavian.
III. THE VENA CAVA INFERIOR AND ITS TRIBUTARIES
All the veins of the abdomen, pelvis, and lower extremities, with the exception of the superior epigastric (p. 666), and ascending lumbar vein (p. 521), which join with the superior caval system, enter directly or indirectly into the vena cava inferior. The veins corresponding to the parietal branches of the abdominal aorta, except the middle sacral vein, open directly into the vena cava inferior; the middle sacral vein only indirectly through the left common iliac vein. Of the visceral veins corresponding to the visceral branches of the abdominal aorta, those which return the blood from the stomach, intestines, pancreas, and the spleen end in a common trunk called the portal vein.
The portal vein [vena portae] enters the liver and there breaks up into a network of smaller vessels somewhat after the manner of an artery. This network contains venous blood, and is moulded upon the tissue-elements of the organ itself. The smaller vessels consist, like capillaries (from which they differ in developmental history) of intima only; they are called sinusoids. The venous blood is returned from the sinusoidal plexus by the hepatic veins which open into the vena cava inferior as that vessel lies in the fossa venae ca,v£e of the liver.
Of the other visceral veins, both renals, the right suprarenal, and the right spermatic or ovarian open directly into the vena cava inferior; whilst the left suprarenal and left spermatic or ovarian are drained through the left renal.
Two of the superficial veins of the lower part of the anterior abdominal wall, the superficial epigastric and superficial circumflex iliac, enter the great saphenous vein; and two of the deep veins from the like situation, the inferior epigastric and deep circumflex iliac, enter the external iliac vein. The blood in these vessels, however, can flow upward as well as in the normally downward direction. In obstruction of the vena cava inferior they become greatly enlarged, and form, with the superior epigastric vein and with other superficial veins of the thorax with which they anastomose, one of the chief channels for the return of the blood from the lower limbs.
The vena cava inferior (fig. 529) is the large vessel which returns the blood from the lower extremities and the abdomen and pelvis. It is formed by the confluence of the right and left common iliac veins opposite the body of the fifth lumbar vertebra, ascends in front of the lumbar vertebrae to the right of the abdominal aorta, passes through the caval opening in the diaphragm, and ends in the lower and back part of the right atrium of the heart on a level with the lower border of the ninth thoracic vertebra. At its origin it lies behind the right common iliac artery on a plane posterior to the aorta, but as it ascends it passes slightly forward and to the right, reaching a plane anterior to the aorta, and becoming separated from that artery by the right medial crus of the diaphragm and the caudate lobe of the liver. While in contact with the liver it lies in a deep groove [fossa venae cavje] on the posterior surface of that organ, the groove being often converted into a distinct canal by a thin portion of the hepatic substance bridging across it. As it passes through the diaphragm its walls are attached to the tendinous margins of the caval opening, and are thus held apart when the muscle contracts. On the thoracic side of the diaphragm it Hes for about 1.2 cm. (I in.) within the pericardium, the serous layer of that membrane being reflected over it.
Relations. — In front it is covered by the peritoneum, and crossed by the right spermatic artery, branches of the aortic plexus of the sympathetic, the transverse colon, the root of the mesentery, the duodenum, the head of the pancreas, the portal vein, and the liver. The median gi'oup of the lumbar lymphatic nodes are also in front of it below, and at its commencement the right common iliac artery rests upon it.
(1) The renal veins [vv. renales] (fig. 529) return the blood from the kidneys. They are short but thick trunks, and open into the vena cava nearly at right angles to that vessel. The vein on the left side, like the kidney, is a little higher than on the right, and is also longer, in consequence of its having to cross the aorta.
The left vein crosses in front of the aorta, just below the origin of the superior mesenteric artery. It is covered by the inferior portion of the duodenum, and receives the left spermatic, or the left ovarian in the female, and usually the left suprarenal, and sometimes the left phrenic. There are rudiments of valves in each vein where it joins the vena cava. Those on the right side, however, are less well marked.
(2) The suprarenal veins [vv. suprarenales] (fig. 529). — ^There is usually only one suprarenal vein on each side to return the blood brought to the suprarenal body by the three suprarenal arteries. On the right side the vein opens directly into the vena cava, above the opening of the right renal vein. On the left side, it opens into the left renal.
(3) The spermatic veins [vv. sperraaticaj] (fig. 529) retui-n the blood from the testis. They begin by the confluence of small branches from the body of the testis and epididymis. After passing through the subcutaneous inguinal ring, the inguinal canal, and the abdominal inguinal ring, the plexus communicates with the inferior epigastric vein and is continued as two veins. Along with the artery the veins pass up beneath the peritoneum, and on the left side also beneath the sigmoid colon, across the psoas muscle and ureter. They receive small tributaries from the ureter and peritoneum, and proceed as a single trunk, on the right side to the vena cava inferior, and on the left side to the left renal vein. There are commonly a number of imperfect valves in the spermatic plexus and a perfect pair at the termination of each spermatic vein. On the left side, however, the terminal valve may be wanting.
The ovarian veins [vv. ovarica3[ begin at the plexus pampiniformis near the ovary, between the layers of the broad ligament. This plexus is larger than in the male and communicates freely with the utero-vaginal plexus of veins, and with the plexus of veins which extends from the hilus of the ovary into the ovarian ligament (fig. 486). After passing from between the layers of the broad Ugament, the plexus unites to form at first two and then a single vessel, which accompanies the ovarian artery, following a course similar to that of the spermatic veins in the male. The right ovarian veins open into the vena cava inferior, the left into the left renal. They usually contain imperfect valves in their plexiform part, and a perfect valve where they join the vena civa and renal vein respectively.
THE PORTAL VEIN 676
(4) The lumbar veins [vv. lumbales], four to five on either side accompany the lumbar arteries and collect venous blood from the muscles of the back and abdomen. They terminate by passing beneath the tendinous arches of the psoas major, along the sides of the lumbar vertebrae, and opening into the vena cava inferior. The veins of the left side are longer than those of the right and pass behind the aorta. Each vein receives a dorsal tributary corresponding in distribution to the dorsal branch of the lumbar artery. Between the dorsal tributaries and the posterior vertebral venous plexus there occurs a free communication. There is also an anastomosis between the main lumbar veins and the anterior vertebral venous plexus around the bodies and transverse processes of the lumbar vertebrae. By means of these communications the intervertebral veins, the internal and external vertebral and spinal plexuses are partly drained. In addition to these anastomoses the lumbar veins are connected with one another and with common iliac, hypogastric, ilio-lumbar, renal, azygos and hemiazygos veins by means of the ascending lumbar vein (p. 66.3).
the vena cava.
(6) The hepatic veins [vv. hepaticse], the largest tributaries of the vena cava, return the blood from the liver. Commencing in the substance of the liver (see Liver), they converge as they approach its posterior surface, and unite to form two or there large trunks, which open into the vena cava as it lies in the fossa vense cavae. Some smaller vessels from the caudate lobe, and other parts of the liver in the nighbourhood of the caval fossa, open directly into the vena cava. The hepatic veins contain no valves, but, in consequence of opening obliquely into the vena cava, a semilunar fold occurs at the lower magin of each orifice.
The veins corresponding to the inferior mesenteric, the superior mesenteric, and to some of the branches of the coeliac artery, do not join the vena cava inferior direct, but unite to form a common trunk — the portal vein.
This vein enters the liver, and breaks up in its substance into sinusoids from which the blood is again ultimately collected by the hepatic veins, and carried by them into the vena cava inferior. The terminal branches of the hepatic artery also empty into the hepatic sinusoids, and their blood likewise finds its way finally into the hepatic veins, and thence into the vena cava inferior. The portal vein and its tributaries have no valves.
The portal vein [v. portae] (fig. 531), is a thick trunk 7 or 8 cm. (3 in.) in length. It is formed behind the head of the pancreas, opposite the right side of the body of the second lumbar vertebra, by the union of the superior mesenteric with the splenic veins. It passes upward and to the right behind the superior part of the duodenum, and then between the layers of the lesser omentum. In the latter situation it passes in front of the foramen epiploicum and is accompanied by the hepatic artery and the hepatic duct. Finally it enters the porta of the liver, and there divides into a right and a left branch. In this course the hepatic artery and the common bile duct are in front, the former to the left, the latter to the right. It is surrounded by branches of the hepatic plexus of the sympathetic nerve, and by numerous lymphatic vessels and some glands. The connective tissue sheath enclosing these structures is called the fibrous capsule of Glisson [capsula fibrosa, Glissoni]. Just before it divides it is somewhat dilated, the dilated portion being called the sinus of the portal vein. The division into right and left branches takes place toward the right end of the porta of the liver. The right branch is shorter and thicker than the left, and supplies the right lobe of the liver and a branch to the quadrate lobe. The left branch is longer and smaller than the right, and supplies the left lobe, and gives a branch to the caudate (Spigelian) and quadrate lobes. It is joined, as it crosses the left sagittal fossa, by a fibrous cord, known as the ligamentum teres hepatis (obUterated vena umbilicalis), and posteriorly by a second fibrous cord, the ligamentum venosum (oblietrated ductus venosus). The position of the original course of the umbilical vein across the left portal is marked, in. adult life, by a dilation of the latter vein, called the umbilical recess.
mesenteric, and the splenic.
The pyloric vein begins near the pylorus in the lesser curve of the stomach, and, running from left to right with the right gastric artery, opens directly into the lower part of the portal vein. It receives branches from the pancreas and duodenum.
The coronary vein [v. coronaria ventriculi] (fig. 533) runs with the left gastric artery at first from right to left, among the lesser curvature of the stomach, toward the cardiac end, and then, turning to the right, passes across the spine from left to right to end in the portal trunk a
opens into the right branch of the portal vein.
The superior mesenteric vein [v. mesenterica superior] (fig. 534) begins in tributaries whichi correspond witli the branches of the superior mesenteric artery. It courses upward a little in front and to the right of the artery, passing with that vessel from between the layers of the mesentery. It passes in front of the inferior portion of the duodenum, and behind the pancreas, where it joins the splenic vein to form the portal trunk (fig. 531).
Tributaries. — In addition to the tributaries corresponding to the branches of the superior mesenteric artery — viz. the ileo-colica, colica dextra, colica media, and vence intestinales (fig. 534) — it receives the right gastro-epiploic and the pancreatico-duodenal veins just before its termination in the portal vein.
The right gastro-epiploic vein [v. gastroepiploica dextra] (fig. 533) accompanies the artery of that name. It runs from left to right along the greater curvature of the stomach, receiving branches from the anterior and posterior surfaces of that viscus, and from the great omentum, and, passing behind the superior portion of the duodenum, ends in the, superior mesenteric vein just before that vessel joins the portal trunk.
tal vein recess
The pancreatio-duodenal veins [vv. pancreatico-duodenales] (fig. 531) run with the superior and inferior pancreatico-duodenal arteries between the head of the pancreas and the second portion of the duodenum. They receive pancreatic and duodenal veins [vv. pancreaticiE et duodenales] and are collected into a single stem which follows the inferior pancreatico-duodenal artery and ends in the superior mesenteric vein a little below the right gastro-epiploic vein.
.The splenic vein [v. lienalis] (fig. 531) issues as several large branches from the hilus of the spleen. These soon unite to form a large trunk, which passes across the aorta and spine in company with the splenic artery, below which it lies, to join at nearly a right angle the superior mesenteric vein. In this course it lies behind the pancreas; and at its union with the superior mesenteric to form the vena portse in front of the vena cava inferior.
Tributaries. — It receives the short gastric veins [vv. gastricse breves], from the fundus of the stomach, the left gastro-epiploic vein, and the inferior mesenteric vein. As it lies in contact with the pancreas it receives some small pancreatic veins [vv. pancreaticse].
The left gastro-epiploic vein [v. gastroepiploica sinistra] (fig. 533) accompanies the left gastro-epiploic artery. It runs from right to left along the greater curvature of the stomach, receives branches from the stomach and omentum, and opens into the commencement of the splenic vein.
The inferior mesenteric vein [v. mesenterica inferior] (fig. 531) begins at the rectum as the superior hgemorrhoidal vein. This emerges from the hsemorrhoidal plexus in which it communicates freely with the middle and inferior haemorrholdal veins. It passes out of the pelvis with the inferior mesenteric artery; but, after receiving the sigmoid and left colic veins [vv. sigmoideee et V. colica sinistra] which accompany the arteries of the same names, it leaves the artery and runs upward on the psoas to the left of the aorta and behind the peritoneum. On approaching the pancreas it turns medially, and passes obliquely behind that gland to join the splenic vein just before the latter unites with the superior mesenteric to form the vena portse.
The adult portal vein and its tributaries contain no valves, a circumstance which adversely affects the circulation of blood within this system. The liability to excessive pressure in the most dependent part of the portal system is evidenced by the great frequency of the condition known as piles, due to dilatation of the veins of the internal hsemorrhoidal plexus. In earrly life valves are present in the veins of the stomach and of the intestinal wall but these undergo retrogression.
The accessory portal veins. — Since the blood returning from the abdominal portion of the digestive tract and spleen must pass through the hepatic-capillaries before returning to the heart, extensive obliteration of these capillaries, such as occurs in certain diseases of the liver, would prevent the return of the portal blood to the heart were it not for anastomoses between tributaries of the portal vein and those of the caval systems, constituting what have been termed accessory portal veins. Some of the more important of these are — (1) between the branches of the coronary vein of the stomach and the oesophageal veins which open into the vena azygos; (2) between the parumbilical veins [vv. parumbilicales], which communicate with the portal vein above and descend upon the ligamentum teres to the anterior abdominal wall to anastomose with the superior and inferior epigastric and superior vesical veins; (3) between the superior and middle hsemorrhoidal veins, the latter opening into the hypogastric, and (4) between a wide-meshed retro-peritoneal plexus of veins which communicates with the portal vessels over the posterior surface of the liver and the veins of the pancreas, duodenum and ascending and descending colon on the portal side, and with the phrenic and azygos veins on the systemic.
The common iliac veins [vv. iliacae communes], (fig. 536) are formed opposite the sacro-iliac articulation by the confluence of the external iliac and hypogastric (internal iliac) veins. They converge as they ascend, and unite opposite the upper border of the fifth lumbar vertebra and a little to the right of the median line to form the vena cava inferior.
the right common iliac artery to its lateral side, where it is joined by the left common iliac vein.
The left vein lies to the medial side of the left common iliac artery, and, after crossing in front of the promontory of the sacrum and the fifth lumbar vertebra below the bifurcation of the aorta, passes beneath the right common iliac artery to join the right vein and form the vena cava inferior. The left vein may contain an imperfect valve.
The middle sacral vein [v. sacralis media] opens usually as a single trunk into the left common liiac vein. The venae comitantes which form it ascend on either side of the middle sacral artery in front of the sacrum. They communicate with the lateral sacral veins, forming the anterior sacral plexus [plexus sacralis anterior] which receives the sacral intervertebral veins, and anastomoses freely with the neighbouring lumbar and pelvic veins. Below, the middle sacral veins communicate with the hsemorrhoidal veins.
of the hypogastric artery. It varies considerably in length, but is usually quite a short trunk, extending from the upper part of the great sciatic foramen to the sacro-liac articulation, where it joins the external iliac to form the common iliac vein. It lies behind and a little medial to the hypogastric artery. It contains no valve.
gluteal (sciatic), internal pudendal, and (in the female) the uterine veins; also branches from the pudendal, vesical, and haemorrhoidal plexuses. The single umbilical vein-^the vein corresponding to the right and left hypogastric arteries and their continuation, the umbilical arteries — does not enter the pelvis, but, leaving the umbihcal arteries at the navel, passes along the falciform ligament to the liver. After birth it is converted into the hgamentum teres hepatis. (See Portal Vein, p. 675.)
The superior gluteal veins [vv. glutete superiores] accompany the superior gluteal artery and, passing through the upper part of the great sciatic foramen, open into the hypogastric vein near its termination, either separately or as a single trunk.
superior gluteal. At times they join the common iliac vein.
The lateral sacral veins [vv. sacrales laterales] (fig. 536) join the superior gluteal or the hypogastric at or about the same situation as the gluteal. They form with the middle sacral veins a ple.xus in front of the sacrum, which receives tributaries from the sacral canal.
The obturator vein [v. obturatoria] (fig. 536), which lies below the obturator artery as it crosses the side of the pelvis, opens into the front of the hypogastric vein a little below the superior gluteal. Its branches correspond to those of the artery.
further special description of them is required. They all contain valves.
Tliese veins communicate with the dorsal vein at the root of the penis In its course the internal pudendal vein runs with the internal pudendal artery, receiving tributaries corresponding to the branches of that vessel. It. terminates in the lower part of the hypogastric vein.
In this course it receives large tributaries from the interior of the organ, which, emerging for the_ most part between the corpus cavernosum lu-ethrai and corpus cavernosum penis, wind obliquely over the lateral surface of the latter structure to the dorsum of the penis to end in the dorsal vein. It then goes between the subpubic linament
and the upper part of the fascia of the urogenital diaphragm (fig. 542). Here it bifurcates, each branch passing backward and downward to the pudendal plexus of veins. At times the dorsal vein begins as two branches, which run between the dorsal arteries and only unite to form a single trunk about 3.7 cm. (Ij in.) from the symphysis. After dividing into a right and a left branch within the pelvis, each vessel generally communicates with the obturator vein by a branch passing over the back of the pubis to the obturator foramen.
Anterior jugular vein
Edge of superficial cervical fascia Superficial cervical artery and vein Cephalic vein opening into the deep vein of neck (variation)
The pudendal plexus [plexus pudendalis] surrounds the prostate and the neck and fundus of the bladder. It receives in front the right and left divisions of the dorsal veins of the penis, and communicates with the posterior scrotal veins [vv. scrotales posteriores] and with the hasmorrhoidal plexus. The prostatic veins and the vesical plexus open into it, and it also communicates with the internal pudendal vein. The veins forming the plexus are of large size, especially in old men, in whom they often become varicose, and contain phleboliths, or vein-stones
In the female the smaller pudendal plexus surrounds the urethra and receives the dorsal and deep veins of the clitoris [vv. dorsales et profunda clitoridis], veins from the vestibule, and the posterior labial veins [w. labiales posteriores]. It communicates freely with the uterovaginal plexus and is drained by the hypogastric veins.
The vesical plexus [plexus vesicalis] surrounds the apex, the sides, and the anterior and posterior surfaces of the bladder. It is situated between the muscular coat and the peritoneum, and where the bladder is uncovered by peritoneum external to the muscular coat in the pelvic cellular tissue. It opens into the pudendal plexus.
The utero-vaginal plexus [plexus uterovaginalis] connects with the haemorrhoidal, vesical, and uterine plexuses. Its lower part drains thi'ough the internal pudendal veins and the pudendal plexus, and its upper protion largely through the ovarian veins, and partly through the uterine veins [vv. uterinae] to the hypogastric (fig. 530).
The hEemorrhoidal plexus [plexus haemorrhoidalis] surrounds the rectum, and is situated at the lower part of that tube. It consists of two portions, one of which, the internal haemorrhoidal plexus, is situated between the muscular and mucous coats, while the other, the external hsemorrhoidal plexus, rests upon the outer sui-face of the muscular coat. The veins of this latter plexus terminate in the inferior, middle, and superior hsemorrhoidal veins. The inferior [w. hiemorrhoidales inferiores] join the internal pudendal; the middle [v. haemorrhoidalis media] accompanies the middle hsemorrhoidal artery and opens into the hypogastric and superior haemorrhoidal veins; the superior (p. 678) forms the commencement of the inferior mesenteric vein, and through this the blood gains the portal vein. None of these veins have any valves, hence the enlargement of the inferior htcmorrhoidal veins, when the portal vein is obstructed, as in cirrhosis of the liver. Through the haemorrhoidal veins a free communication is established between the systemic and portal system of veins.
The external iliac vein [v. iliaca externa] (fig. 536), is the upward continuation of the femoral. Beginning at the lower border of the inguinal ligament, it accompanies the external iliac artery medially upward along the brim of the minor pelvis, lying at first on the superior ramus of the pubis, and then on the psoas major muscle. It terminates by joining the hypogastric vein behind the hypogastric artery, opposite the lower border of the sacro-iliac articulation, to form the common iliac vein. It lies at first medial to the external iliac artery, and on the left side remains medial to the artery throughout its course. On the right side, however, as it ascends, it gradually gets behind the artery. It contains one or two valves.
In addition to the femoral, the external iliac receives the inferior epigastric vein [v. epigastrica inferior] (fig. 536) and the deep circumflex iliac vein [v. circumflexa ilium profunda] (fig. 541), which accompany the arteries of the same name.
The plexus of superficial veins of the anterior abdominal wall is continuous with that of the thorax (fig. 537). Its main channels are the superficial circumflex ihac, the superficial epigastric, and the external pudendal, all of which open into the great saphenous vein. These communicate, by means of subcutaneous abdominal veins, with the superior epigastric vein, and, by means of the thoracoepigastric veins, with the lateral thoracic and costo-axillary. The superficial veins communicate verj' freely with the deeper veins of the abdominal wall, and, by means of parumbilical veins, they communicate to a slighter extent with the portal system.
The veins of the lower extremity are divided into the superficial and the deep. The superficial veins lie in the subcutaneous tissue superficial to the deep fascia, through which they receive numerous communicating branches from the deep veins. They are collected chiefly into two main trunks, which, beginning on the foot, extend upward, one, the great saphenous, lying antero-medially, and the
other, the small saphenous, postero-laterally. The former finally joins the femoral vein by passing through the deep fascia at the groin; the latter, the popliteal by perforating the fascia at the ham. The deep veins, on the other hand, accompany their corresponding arteries. All the veins of the lower limb have valves which are more numerous than in the veins of the upper extremity and in the deep than in the superficial veins.
EXTREMITY
The superficial veins of the lower limb begin in the plexuses of the foot. The dorsal digital veins [vv. digitales pedis dorsales] collect blood from the dorsal surfaces of the toes and unite in pairs, around each cleft, to form the dorsal metatarsal veins [vv. metatarsese dorsales pedis]. The dorsal metatarsal veins, of which the first and fifth are larger than the others, join the dorsal venous arch [arcus venosus dorsalis pedis]. This arch is convex toward the toes and crosses near the bases of the metatarsal bones. From the medial and lateral ends of the arch the great and small saphenous veins, respectively, take origin. The area of the dorsum of the foot contained between the arch and the two saphenous veins is covered by the dorsal venous rate [rete venosum dorsale pedis] which extends as high as the ankle-joint (fig. 539).
On the plantar surface the plantar digital veins [w. digitales plantares] return the venous blood to the clefts of the toes and unite to form the common digital veins [vv. digitales communes pedis]. The common digital veins join freely with one another on the sole to form the plantar venous rete [rete venosum plantare]. There are numerous communications between the superficial veins of the dorsum and sole. These occur both in the clefts of the toes, by means of the intercapitular veins [vv. intercapitulares], and around the margins of the foot. Communications between the superficial and deep veins of the foot are very free (fig. 540).
The great (or internal) saphenous vein [v. saphena magna] (fig. 538) commences as the medial end of the dorsal venous arch, and, after receiving branches from the sole which join it by turning over the medial border of the foot, passes upward in front of the medial malleolus, and then obliquely upward and backward about a finger's breadth from the posterior border of the tibia in company with the saphenous nerve, which becomes superficial just below the knee. Continuing its course upward, it passes behind the medial epicondyle, and then runs upward on the medial side of the front of the thigh to about 3.7 cm. (li in.) below the inguinal Hgament, where it dips through the fossa ovalis (saphenous opening) in the fascia lata, and ends in the femoral vein.
Tributaries. — In its course up the leg and thigh it receives numerous unnamed cutaneous tributaries. As it passes up the thigh it often receives a large vein, the femoro-popliteal which communicates with the small saphenous, and several of the cutaneous veins on the lateral part of the thigh, and a second vein, the accessory saphenous [v. saphena accessorial, formed by the union of the cutaneous veins from the medial and back part of the thigh (fig. 538). The great saphenous vein contains from ten to twenty valves.
Immediately before entering the fossa ovalis the great saphenous vein receives the superficial epigastric, superficial circumflex iliac, and external pudendal veins, though any of these veins — or all of them — may pierce the fascia separately and enter the femoral vein.
The small saphenous vein [v. saphena parva] (fig. 539) begins at the lateral end of the venous arch on the dorsum of the foot. After receiving branches from the sole, which turn over the lateral border of the foot, it passes behind the lateral malleolus, and then upward and, lying at first along the lateral side of the tendo Achillis, afterward along the back of the calf, in company with the sural (short saphenous) nerve, to about the lower part of the centre of the popliteal space, where it perforates the deep fascia, and, sinking between the two heads of the gastrocnemius, opens into the popliteal vein.
iliac vein
communicates at intervals, through transverse or intermuscular branches, with the deep veins accompanying the peroneal artery. Just before perforating the deep fascia, it receives a large descending branch, the vena femoropoplitea, from the lower and back part of the thigh. This
communicates with a plexus of veins upon the posterior and lateral regions of the thigh and with the great saphenous. In many cases the small saphenous vein is entirely drained, by means of the femoro-popliteal, into the great saphenous. Under these circumstances the usual place of termination of the small saphenous is marked by a small vein opening into the popliteal. A small offshoot from the inferior sural branch of the popliteal artery accompanies this vein for a
The deep veins of the lower extremity accompany the arteries, and have received corresponding names. From the foot to the knee there are two veins to each artery. These veins run on either side of the corresponding artery, and com-
DEEP VEINS OF THE LOWER LIMB
municate at frequent intervals with each other across it. They are known as the venae comitantes. From the knee upward there is a single main vein to each artery, except at the back of the thigh and in the gluteal region, where there are commonly two.
Small saphenous vein
The veins of the foot and leg. — The deep veins of the foot become separated from the superficial where the plantar metatarsal veins [vv. metatarsese plantares] leave the plantar digital and intercapitular veins to accompany the plantar metatarsal arteries. The plantar metataisal veins empty into the plantar venous arch
They follow the posterior tibial artery up the leg, receiving tributaries corresponding to its branches, the largest of which are the peroneal veins [vv. peronefe]. They unite with the anterior tibial vense comitantes at the lower border of the popliteus muscle.
The anterior tibial veins [vv. tibiales anteriores] begin in the dorsal venous rete and accompany the anterior tibial artery up the leg receiving tributaries corresponding to branches of the artery.
branches, with the superficial veins.
The popliteal vein [v. poplitea] (fig. 542), is formed by the confluence of the venae comitantes of the anterior and posterior tibial arteries at the lower border of the popliteus, and extends upward to the opening in the adductor magnus at the junction of the middle and lower third of the thigh, where it changes its name to femoral.
It accompanies the popliteal artery, lying superficial to it in the whole of its course, and tightly bound down to it by its fascial sheath. At the lower part of the space it is a little medial to the artery, but, crossing the vessel obliquely as it ascends, lies a little lateral to it at the upper part of the space. The tibial (internal popliteal) nerve lies superficial to the vein, being lateral to it above, then posterior to it, and then a little to its medial side. The popliteal vein contains two or three valves.
Lateral calcanean branches and veins
The popliteal receives the small saphenous vein. It is also joined on its lateral and medial sides by the accessory popliteal veins [vv. popliteoe accessorise] which form common trunks of termination of the sural and articular veins of the respective sides. The medial vein receives in addition, through a plexus extending as high as the opening in the adductor magnus, the veins accompanying the a. genu suprema.
The femoral vein [v. femoralis], the continuation of the popliteal upward, extends from the tendinous opening in the adductor magnus to the inguinal ligament. In this course its relations are similar to those of the femoral artery. As the vein passes through the adductor canal, it lies behind and a little lateral to the artery. At the apex of the femoral trigone (Scarpa's triangle) it is still posterior to the artery, but gradually passes to the medial side as it ascends through the trigone (fig. 541).
In the neighbourhood of the inguinal hgament the femoral vein hes on the same plane as the artery from which it is separated by a delicate prolongation of the fascia stretching between the front and back layers of the femoral sheath. On the medial side the vein is separated by a similar septum from the femoral canal. The femoral vein contains five pairs of valves.
Tributaries. — The femoral vein receives (in addition to the great saphenous vein, and, in some cases the superficial veins of the epigastrium and groin) the profunda veins and a variable number of small femoral vense comitantes.
The profunda femoris veins [vv. profunda femoris) arise from the vense comitantes corresponding to branches of the profunda femoris artery. The medial and lateral circumflex veins [w. circumflex femoris mediales et laterales] collect blood from the muscles of the adductor and lateral rotator regions. The perforating veins anastomose with femoro-popliteal and other veins of the posterior femoral region, and with the circumflex and accessory popUteal veins. They return blood from the femur and the adductor, hamstring and vasti muscles.
The venae comitantes, much smaller than the main femoral vein, accompany the femoral artery on either side. They anastomose with one another, with the femoral, and often with the popliteal vein. They terminate in the femoral a short distance above the profunda veins.
MORPHOGENESIS AND VARIATIONS OF THE VEINS
The veins of the adult human body tend to accompany the arteries; this tendency is more pronounced in the trunk, neck, and extremities than in the cranium. Developmental history shows that the primitive distribution of the veins of the trunk resembles that of the arteries of the same region in its bilateral symmetry only. Also that the changes which modify the primitive bilateral symmetry of the chief veins are not only more extensive but of a different nature from those producing a similar effect upon the arteries. In both cases the main bodyvessels begin as a pan- of main longitudinal trunks and end as a main unpaired channel (or channels in the case of the venous system) situated near the median plane of the body. In the ease of the venous system the change results from wholesale destruction of the vessels on the left of the body accompanied by enlargement of those upon the right. In the arterial system destruction occurs to a much more limited extent; the definitive channel results mainly from blending of the two primitive aortse.
The main venous channels of the cranium and extremities are primitively superficial; in the cranium they remain so. In the extremities new veins are formed which follow the main arteries; to these the more primitive channels become tributary.
The heart, as soon as it assumes the simple tubular form is found to receive four veins. These, the two vitelline and two umbilical veins, enter the sinus venosus, a vitelline and an umbilical vein on either side. The umbilical veins are lateral to the vitellines, and are paired within the body only; they arise from the placenta, and traverse the belly-stalk as a single trunk. The vitelline veins return blood from the yolk sac, and, at first, are independent throughout.
At a later period two other pairs of veins arise for the venous drainage of the embryonic body. They are the pre- and post-cardinals which drain the cephalic and caudal regions respectively. The right pre-cardinal vein unites with the right post-cardinal to form the right common cardinal (duct of Cuvier). The latter runs in a medial direction to join the sinus venosus lateral to the right umbilical. On the left side the arrangement matches that on the right to produce a primitively symmetrical pattern.
During development changes are brought about in the primitive veins which end in the production of the adult venous system as follows: the common and pre-cardinals, together with the subclavian veins and the cephalic ends of the post-cardinals, are transformed into the vena cava superior and its larger tributaries. The remainder of the post-cardinal system is instrumental in the production of the vena cava inferior and its tributaries. FinaUy the intra-embryonic portions of the vitelline and umbilical veins participate in the formation of the portal and hepatic systems of veins together with the proximal end of the vena cava inferior.
The pre-cardinal veins at first return blood from the head only, but as the heart recedes into the thorax the cardinal veins migrate with it. In so doing the common cardinals lag somewhat behind and in consequence their direction, primitively transverse, approaches the Ion-
gitudinal. The pre-cardinals, which have increased in relative length, now course symmetrically along the neck into the thorax. At a stage of 16 mm., the definitive subclavian vein has migrated from the common to the pre-cardinal, which henceforth receives the main venous flow from the upper extremity as well as from the head. The symmetrical arrangement of the cardinal veins is disturbed at a stage of about 18 mm., by the development of a transverse connection between the right and left pre-cardinals (fig. 544). This connection, the left innominate vein, arises, probably, by the development of cross-anastomoses uniting the lateral veins draining the developing thymus and thyreoid glands. On the right side of the embryo the veins of the adult are now recognisable as follows: — the vein (pre- and common cardinal) extending from the left innominate to the heart becomes the vena cava superior. The precardinal, from the left innominate to the subclavian, becomes the right innominate. From the subclavian to the cranium it becomes the internal jugular.
The vessel of the left side corresponding to the vena cava superior now rapidly diminishes in size. It extends from the left innominate vein (the extreme left end of which corresponds in its method of formation to the entire right innominate) to the right atrium. In so doing it passes ventral to the aortic arch and the foot of the left lung, dorsal to the left artium, and through part of the coronary sulcus.
A.c.v; pre-cardinal vein; A.V., otic vesicle; Inf. Pet., inferior petrosal sinus; L., eye; O.V., superior ophthalmic vein; S.L.S., superior sagittal sinus; S.P.S. sphenoparietal sinus; S.R., sinus rectus; S.S., middle cerebral vein; T.H., confluens sinuum; V., semilunar ganglion; V.C.A., v. cerebralis anterior; V.J., internal jugular vein; V.C.L., v. capitis lateralis; V.O.M. or sup. pet., v. cerebralis media and superior petrosal sinus; V.C.P. or L.S., v. cerebralis posterior and transverse sinus.
The segmental veins draining the second, third and fourth intercostal spaces of the left side open, by a common stem formed by the left pre-cardinal, into the left innominate. The corresponding segmental veins of the right side open, by a common stem, into the vena azygos. The collecting stem, on either side, is the vena intercostais suprema. The method of origin of the azygos, hemiazygos and accessory hemiazygos veins is treated with the inferior caval system. Below the superior intercostal tributary, the left superior cava is lost to within a short distance of the sinus venosus. Here its lower end persists as the oblique vein of the left atrium and the left end of the coronary sinus. The former course of the left superior cava is often indicated in the adult by a small fibrous cord, uniting the extremities of the persisting veins and passing through the ligamentum v. cavoe sinistrae (p. 523).
Within the cranium the pre-cardinal veins are primitively in close contact with the brain and medial to the semilunar, acustico-facial, glossopharyngeal and vagus ganglia. The portion of each vein extending from the semilunar ganglion to the facial canal (its exit from the cranium) early becomes involved in a process of anastomosis-migration which eventually places it lateral to the ganglia and to the otocyst. The new vein formed in the latter situation is called the vena capitis laterahs (fig. 543). The portion of the pre-cardinal vein which remains medial to the semilunar ganglion persists as the adult cavernous sinus and receives a primitive vein (v. cerebralis anterior) which drains the orbit and the mid- and forebrain. The forebrain tributaries of
the right and left v. cerebralis anterior unite to from a median vein, the definitive superior sagittal sinus, wliicli at first drains into the cavernous sinus. There are two other primitive cerebral veins; the v. cerebralis media and v. cerebralis posterior. The first receives blood from the cerebellar region and drains into the cavernous sinus. The second, the v. cerebralis posterior, also receives blood from the hind-brain and, leaving the skull through the jugular foramen, joins the pre-cardinal (internal jugular) vein m the neck. Several changes occur from now on (fig. 543) which bring about the definitive relations of the dural sinuses and transfer the main venous exit from the stylomastoid to the jugular foramen. The right v. cerebralis posterior joins the superior sagittal sinus and this becomes the right transverse sinus. The left V. cerebralis posterior communicates with the junction of the superior sagittal and right transverse sinuses (now the confluens sinuum) and becomes the left transverse sinus. The confluens receives the sinus rectus, which forms its adult connections with the inferior petrosal sinus and great cerebral vein. The v. cerebralis media joins the transverse sinus to become the superior petrosal sinus. The latter forms a new (intracranial) means of drainage for the cavernous sinus and its tributaries. The original drainage channel of the cavernous sinus (v. capitis lateralis), having been supplanted, disappears. The superior cerebral veins drain into the superior sagittal sinus. The remaining portion of the interrupted v. cerebrah's anterior drains the middle cerebral vein and spheno-parielal sinus. The inferior petrosal sinus arises de novo.
In the upper extremity the venous drainage is at first superficial and opens into the postcardinal and umbilical veins. The ulnar limb of the loop-like early venous channel (marginal vein) becomes the primitive ulnar vein, but does not open into the pre-cardinal until a stage later than that of 10 millimetres. The primitive ulnar forms the basilic, part of the brachial, the axillary, and subclavian veins. It receives the large thoraco-epigastric trunk. The cephalic vein, which at first joins the external jugular, is of secondary formation. The venoe comitantes are formed later still.
The great veins of the thorax may present variations from the normal as a result of absence of the left innominate vein. In this case there are two superior cavse, not necessarily of equal size, each of which receives an internal jugular and subclavian vein. Persistence of the left
Fig. 544. — The Transformation of the Postcardinal System of Veins, C representing THE Adult. The Wolffian Body is Dotted. (Lewis.) a.c, precardinal; as. 1., ascending lumbar; az., azygos; c, caudal; c.h., common hepatic; c. il., common iliac; C.S., coronary sinus; d.C, common cardinal; g., spermatic or ovarian; h., hepatic; h.-az., hemiazygos; h.-az. ac, accessory hemiazygos (here draining into the intercostalis suprema); i. j., internal jugular; l.c.i., left common iliac; 1. in., left innominate; m.s., middle sacral; p.c, posterior cardinal; r., renal; r.a., renal anastomosis; r.c.i., right common iliac; r. in., right innominate; s., suprarenal; s-c, subcardinal; s-cl., subclavian; s.l., sinusoids; v.c.i., vena cava inferior; v.c.s., vena cava superior.
vena cava superior without failure of the left innominate may occur in three classes of cases: (a) In which both cavse are present, equal in size or asymmetrical, (b) In which the left cava only occurs, associated with situs inversus, (c) In which the left cava only is present, without situs inversus. The left vena cava superior, when present, crosses in front of the aortic arch and
The veins of the neck, face, and scalp. — These veins have so many variations in detail that it is difficult, in the case of some veins, to assign their normal distribution. The external jugular, for instance, is usually described in Enghsh text-books as a tributary of the subclavian vein; it is assigned by the BNA to the internal jugular. It is frequently found to open into the angle between the two, or, forming a plexus with its tributaries, drain into both. The origin of the external jugular vein is also exceedingly variable. The external jugular may be small, or absent, in which case the anterior jugular is large. The reverse may be the case since the external jugular frequently receives the posterior, and sometimes the common facial. Fortunately venous variations are not of prime surgical importance.
Veins of the cranium. — The venous sinuses of the dura mater are not subject to important variations. Variations in the relative size of the transverse simises have been referred to on p. 651. The petrosquamous sinus, occasionally present, is described on p. 653. The occipital and inferior sagittal sinuses are frequently absent.
The cerebral veins are liable to great variation in detail: the great cerebral vein may be absent, as a single trunk, in which case the internal cerebral veins open directly into the sinus rectus. The middle cerebral vein may open into the sphenoparietal, or superior petrosal sinus or into the basilar plexus.
Veins of the upper extremity. — The subclavian vein is occasionally posterior to the artery, or spUts to enclose the latter and the anterior scalenus. Either case represents a partial retention of the early condition in which the vein passes behind the brachial plexus. Variations in the superficial veins have been referred to on p. 668. The question of the most common distribution of these vessels has lately been fully reviewed by Berry and Newton. The cephalic vein occasionally opens into the external jugular by persistence of the embryonic jugulo-cephahc vein.
The right and left post-cardinal veins (fig. 544) are at first symetrical in size and position. Early in development each posterior cardinal vein becomes involved in the growth of the corresponding mesonephros, and the original venous channel is converted into a system of sinusoids. In the sinusoidal circulation of each mesonephros two main longitudinal venous channels soon make their appearance. One lies ventro-medial to the mesonephros and is called the sub-cardinal vein. The other, which lies dorsal to the mesonephros, receives the segmental veins and is frequently called the post-cardinal. Since the mesonephric segment of the post-cardinal vein has obviously passed out of existence, the vein in question (unlabelled in fig. 544) wQl be here distinguished as the dorsal trunk. The sub-cardinals communicate freely between themselves and with the dorsal trunks, lie ventral to the mesonephric arteries, and are at first symmetrical. The cephalic end of the right sub-cardinal now acquires a communication with the common hepatic vein, thus providing a new means of drainage for the sub- and post-cardinal systems (fig. 544) . The rapidly enlarging main venous channel resulting from this alternative niethod of drainage follows the right dorsal trunk as far as the level of the permanent renal veins. It is then transferred, by means to an anastomosing channel, to the right sub-cardinal and, through this, to the common hepatic vein; it becomes the vena cava inferior. From now on the portions of the sub-cardinal veins not participating in the formation of the cava dwindle rapidly. A cross anastomosis between the right and left sub-cardinals persists as the portion of the adult left renal vein which crosses ventral to the aorta. By means of it the remainder of the left renal; thfe left internal spermatic and left suprarenal veins are connected with the vena cava. The left lumbar and left common ihac veins are also transferred to the vena cava, probably by direct anastomosis with the left post-cardinal vein. The vena cava inferior is at first lateral to the right ureter, its transference to the medial side occurs through anastomosis.
The portion of the right posterior cardinal vein above the mesonephric region, together with its continuation into the dorsal trunk, becomes the azygos vein (fig. 544). The corresponding vessel upon the left side is transformed into the accessory hemiazygos and hemiazygos veins. The hemiazygos vein is drained into the azygos by means of an anastomosing channel which may also drain the accessory hemiazygos. The variability of the means of drainage of the accessory hemiazygos vein, by means of anastomosing channels, is referred to onp. 663. The ascending lumbar veins are anastomosing channels of new formation.
In the lower extremity, as in the upper, the original superficial plexus is gradually drained by a loop-Uke marginal vein. The fibular limb of this loop, the primitive fibular vein, becomes small saphenous; it follows the sciatic nerve and opens into the post-cardinal. The next vein to be developed is the great saphenous; the small saphenous is transferred to this by an anastomosing vein which is usually present in the adult — the femoropopliteal vein. The deep veins are of later formation. The drainage of the small saphenous is usually taken over by the popliteal vein.
In determining the probable embryonic cause of variations of the vena cava inferior the possibility of abnormal persistence of the sub-cardinal veins must be remembered. The position of transverse anastomoses with regard to the aorta is often the key to diagnosis. Instruc-
(1) The inferior vena cava, in cases of transposition of the viscera, may he on the left side of the aorta. (2) Without transposition it may also lie to the left of the aorta, crossing to the right to gain the caval opening immediately below the diaphragm, or after receiving the left renal vein. (3) It may be double, the left cava than usually passing across the aorta into the right after receiving the left renal vein. A communication between the right and left veins in the position of the normal left common iliac vein may or may not then exist. (4) The inferior vena cava may be absent, the blood from the lower extremities passing by a large vein in the position of the ascending lumbar and azygos veins through the diaphragm to open into the superior vena cava. The hepatic veins then open directly into the right atrium through the normal caval opening in the diaphragm. (5) The inferior vena cava may receive the left spermatic vein. (6) It may receive a left accessory renal vein passing behind the aorta, and into this the usual tributaries of the left renal vein may open. (7) It may receive several accessory renal veins; as many as seven on each side have been met with. (8) The lumbar veius may enter it on one or both sides as a common trunk.
The portal system arises by transformations in the vitelline and umbilical veins. The proximal ends of the vitelline veins, where they lie between the umbilicals, are early enveloped in, and invaded by, the growing liver. The columns of liver cells, while not penetrating the endothelium, subject the vitelline veins to a process of fenestration by which the original channels are subdivided into innumerable smaller vessels or sinusoids. The sinusoids arising from the two vitelline veins intercommunicate to form one continuous network in which the vessels are larger in the afferent (portal) and efferent (hepatic) areas than in the intermediate zone.
Fig. 545. — Sbmidiagrammatic Reconstructions of the Veins of the Liver, Ventral Aspect (Mall). A, Embryo of 4.5 mm. Long; B, 4 mm. (more advanced than A); C, 7 mm. d.v., ductus venosus; I., intestine; L., liver; m., superior mesenteric (continued as portal)
The two umbilical veins now form communications with the portal area of the sinusoidal network and eventually lose their original connections with the sinus venosus (fig. 545). The fate of the umbilical veins differs on the two sides; the right degenerates, from the sinus venosus to the common umbilical vein, and leaves the left to receive all the blood flowing from the placenta. The left, having lost its connection with the sinus venosus, discharges its blood partly into the portal sinusoidal zone, and partly, by means of the newly formed direct channel, the ductus venosus, into the right vitelline (fig. 545).
The hepatic end of the right vitelline vein enlarges considerably, for the left vitelline loses its original connection with the sinus venosus. It transmits blood both from the sinusoids and from the ductus venosus to the sinus venosus, and is called the common hepatic.
The vitelline veins are not only connected within the liver, but their distal ends become united upon the yolk-stalk to form a single trunk. A third communication between them is effected by a transverse vessel passing dorsal to the duodenum. The portion of the right vitelline below the transverse vessel disappears, as does the portion of the left between it and the liver. A tortuous vitelline vein is thus produced which enters the liver by passing dorsal to the intestine from left to right. This vessel is joined, to the left of the intestine, by the superior mesenteric vein and, dorsal to it, by the splenic. When the portion of the vitelline below the termination of the superior mesenteric finally disappears the vessel extending from the splenic vein to the liver becomes the portal vein of the adult.
The changes which accompany the transformation of the foetal type of circulation into that of the adult are initiated by the first inspiration. Prior. to this act the functions of external respiration and digestion are performed by the
Fig. 546.^The Heart, with the Arch op the Aorta, the Pulmonary Artery, the Ductus Arteriosus, and the Vessels concerned in the Fcetal Circulation. (From a preparation of a fcetua in the Museum of St. Bartholomew's Hospital.)
arteries and returning through the umbilical vein.
At the time of birth the right and left chambers of the heart communicate only by means of an oblique passage between the overlapping atrial septa (p. 511) . The pulmonary artery and descending aorta communicate by means of the ductus arteriosus (p. 508).
Arterial blood, transmitted from the placenta through the umbilical vein, passes almost entirely by way of the ductus venosus to the vena cava inferior. From here it passes through the right atrium; then, obliquely between the atrial septa into the left atrium, from which it passes through the left ventricle and into the ascending aorta. Escaping largely through the branches of the aortic arch, it is distributed to the head and upper extremities, and returned to the vena cava superior. Having reached the right atrium it passes, to the right of the stream from the vena cava inferior fp. 513), through the atrio-ventricular ostium into the right ventricle. The blood issuing from the right ventricle into the pulmonary artery goes almost entirely (the lungs being functionless) into the ductus arteriosus and so into the descending aorta. Having performed two circuits, the blood returns to the placenta through the umbilical branches of the. hypogastric arteries.
The two streams, arterial and semi-venous, cross one another in the right atrium. The degree of intermixture, if any, which occurs in this cavity has been the subject of much discussion; for literature and experimental evidence on this point see Pohlmann, A. (Johns Hopkins Hosp. Bui., Vol. 18, 1907.)
When the lungs assume their function at birth the pressure in the left atrium is suddenly raised by an inrush of blood. The overlapping atrial septa (primum and secundum) are brought into lateral apposition and thus the blood entering the right atrium finds but one exit — the atrio-ventricular ostium. Since the vessels of the expanded lungs now transmit a greatly increased volume of blood, the stream passing through the ductus venosus is diminished proportionately. The blood traversing the aortic arch, released from the check exerted by the lateral stream pouring from the ductus arteriosus, passes more readily into the descending aorta; thus the adult equilibrium is established.
References for blood-vascular system. — A. Heart: (Development) Born, Archiv f. mikr. Anat., Bd. 33, 1889; His, Anatomie menschl. Embryonen, 1880-85, Anatomie des menschl. Herzens, 1886; Tandler, in Keibel and Mall's Human Embryology. (Morphology) MacCallum, Johns Hopkins Hospital Reports, vol. 9, 1900; Mall, Amer. Jour. Anat., vol. 11, 1911, vol. 13, 1912; (Atrio-ventricular bundle) Keith and Flack, Jour. Anat. and Physiol., vol. 41, 1907. B. Arteries. (Development) Evans, in Keibel and Mall's Human Embryology; (Pulmonary) Bremer, Anat. Rec, vol. 3, 1908; (Internal mammary) Mall, Johns Hopkins Hospital Bui., 1898; (Cephalic) Tandler, Morph. Jahrb., Bd. 30, 1902; (C celiac) Tandler, Anat. Hefte, Bd. 25, 1904; (Extremities) Miiller, Anat. Hefte, Bd. 22, 1903; de Vriese, Arch, de Biol., T. 18, 1902; (Variations) Goppert, Morph. Jahrb., Bd. 40, 1909; C. Veins. (Development) Davis, Amer. Jour. Anat., vol. 10, 1910; (Brain) Mall, Amer. Jour. Anat., vol. 4, 1904; (Liver) Mall, Amer. Jour. Anat., vol. 5, 1905; (Cervical) Lewis, F. T., Amer. Jour. Anat., vol. 9, 1909; (Upper extremity) Berry and Newton, Anat. Anz., Bd. 33, 1908; (Vena cava inferior) Neuberger, Anat. Anz., Bd. 43, 1913; v. Alten (ibid): (Sinusoids) Minot, Proc. Boston Soc. Nat. Hist., vol. 29, 1900.
I. GENERAL ANATOMY OF THE LYMPHATIC SYSTEM
THE blood-vascular system has, as a part of its function, the collection of substances from the various tissues of the body which are to be conducted to the other tissues. In carrying on this function it is assisted by a second system of collecting vessels, the lymphatics.
This second system resembles the blood-vascular system in many ways, but differs markedly in others. Like the tslood-vascular system, it is made up of minute endothehal-Uned capillaries, where the absorption of substances occurs, and of larger conducting vessels. It differs from the blood-vascular system' in two important particulars. While the blood-vascular system is provided with a pumping'mechanism by which its fluid content is driven through a complete circuit from the heart, through artery, capillary, vein and back to the heart, the lymphatics merely conduct fluid from, the capillaries to the larger vessels, which eventually empty their contents into the large veins of the neck. The second important difference between the two systems is found in the presence, along the course of the lymphatic vessels, of glands or nodes (fig. 553) [lymphoglandulee] in which the vessels branch out into lymph capillaries. These are lined, as are the absorbing capillaries, with a single layer of endothehal cells, thus permitting an interchange of substances between the contents of the lymph capillaries and the lymphoid tissue around them.
Our present knowledge does not permit an exact statement of the complete extent of the lymphatic system. While, in a general way, the lymphatics may be said to be present whereever blood-capillaries occur, there are certain tissues where lymphatics have not been definitely demonstrated.
I. THE LYMPHATIC CAPILLARIES
The lymphatic capillary, like the blood-capillary, is the portion of the lymphatic system which is chiefly concerned in the specific function of this system. In the blood-capillaries, where the blood is separated from the outside tissues by a single layer of flat endothehal cells, there occurs the interchange of fluid substances and of cells, while the heart, arteries and veins serve to transport the blood, modified in the capillaries, to other parts of the body. Similarly in the lymphatic system, it is in the capillaries, both those most peripheral and those in the lymph nodes, where the absorption and interchange of fluid substances and of cells takes place. Consequently it becomes of prime importance to obtain a clear understanding of the structure of the lymphatic capillaries, their relation to the other tissues, and their mode of functioning. At the outset, however, it must be admitted that our knowledge on this subject is far from complete.
Historical. — Previous to the development of microscopic anatomy, in the middle third of the 19th century, there was no accm-ate knowledge of such small structures as the lymphatic capillary. In order to explain the absorption of substances by the lymphatics, as well as the passage of substances from the blood-vessels through the tissues, various theories were invented. Prominent among such theories was that of the "vasa serosa," of H. Boerhaave and other 18th century anatomists and physiologists, which was perhaps most elaborately developed by Bichat, 1801-03. According to this theory there are two sets of minute vessels, too small for the passage of cellular elements. The one set leads from the blood-capillaries onto the various surfaces of the body and into the loose spaces in the tissues — the "exhalants. " The other set leads from the body surfaces (including the serous cavities) and the loose spaces in the tissues to the lymphatics — the "inhalants" or " absorbants, " which take in fluids by a sucking action.
698 THE LYMPHATIC SYSTEM
This theory was somewhat shaken by the discovery of Magendie, in the first decade of the 19th century, that absorption may take place by the veins, as well as the lymphatics, and by the criticism of early 19th centmy anatomists who developed the teohnio of injection of lymphatics to a high point.
Our present conception of the lymphatic capilJaries may be said to have started with KoUiker who, in 1846, saw, with the aid of the microscope, the lymphatic capillaries in the transparent tails of living frog larvae. He found them to be definite structures made up of a thin wall, from which projected fine-pointed processes, and in which were nuclei. Like Schwann who, in 1837, had studied the blood-capillaries in the tail of the frog larva, he erroneously supposed that the fine processes of the lymphatic capillaries were continuous with similar processes of the surrounding connective-tissue cells. Since, according to the conception current at the time, cells were thought to be hollow structures, with a membranous wall and fluid content, it was concluded that the mode of transmission of fluid from blood to lymphatic capillary took place through canaliculi inside these cells. This conception was elaborated by Virchow, in his CeUular-Pathologie.
In 1862 von Recklinghausen by means of the silver nitrate staining method discovered that the lymphatic vessels are lined with an endothelium made up of flattened cells whose outlines show as fine dark Knes after this treatment. Again, however, as a result of the eagerness to find open passages through the tissues from blood to lymphatic capillary, an erroneous interpretation was made, von Recklinghausen held that the unstained parts outside the lymph vessels represent a system ofj irregularly shaped lymph-canaliculi ("Saftkanalchen") which are in open communication on the one hand with the blood-capiUaries, and on the other with the lymphatics This conclusion has since been disproved by numerous investigators.
In a second series of observations, von Recklinghausen brought evidence in favor of open communications between the lymphatics and the peritoneal cavity. He watched, under the microscope, the passage into lymphatics, through minute openings, of milk, placed on a portion of the central tendon of the diaphragm. These minute openings he termed "stomata. " Cohnheim described similar though smaller openings in blood-capillaries, and His described them in other lymphatic capillaries. Arnold termed the openings in the vessels "stigmata," as distinguished from the openings into the peritoneal cavity, or "stomata."
With the advent into microscopical technic of the various dyes for staining cell-nuclei and protoplasm, and the more precise methods for making histological studies, the endothelial wall of the lymphatic capillary has been definitely established, although much remains to be learned concerning the differences between the lymphatics of the various tissues.
Moreover, recent investigators have failed to find open connections between the lumen of the lymphatic vessel and the tissue outside. Kolossow failed to find the "stomata" of von Recklinghausen and the "stigmata" of Cohnheim, His and Arnold. The "stomata" have been carefully studied by a number of other recent investigators. All agree in finding a complete endothelial lining for the lymphatic capillaries lying underneath the peritoneum and pleura, with no openings or "stomata." Careful studies of the lymphatic capillaries in the transparent tails of living frog larvae, which may be clearly seen with the higher magnifications of the microscope, show that the endothelial lining of these capillaries is complete, with no trace of an opening into the spaces in the tissue outside (E. R. Clark).
Form. — The shape of the lymphatic capillaries has been found to vary enormously in the different parts of the body, where they have been studied. In general they form richly anastomosing plexuses, from which may extend cul-de-sacs, which end bUndly. Such cul-de-sacs are especially noticeable in the dermal papillae, in the filiform papillse of the tongue, and in the intestmal villi. The plexuses are often present in two layers — a superficial and a deep. The vessels of the superficial plexus are of smaller calibre than those of the deep. These two sets of plexuses are particularly well seen in the skin and the gastro-intestinal tract. In relation to the blood-capiUaries, the lymphatic capillaries are generally the more deeply placed.
In cahbre, unlike the comparatively uniform diameter of blood-capillaries, the lymphatics vary enormously. In the same capillary a very narrow part may be succeeded by a very wide one (figs. 547, 548). Teichmann found lymphatic capillaries varying in diameter from a few thousandths of a millimetre to one millimetre. In the capsule of the spleen of the cow some measured more than 1.5 mm.! The capillaries are without valves.
Activity. — That the lymphatic endothelium is not exclusively a passive membrane has been shown by Clark in studies on the lymphatics in the transparent tails of living frog larvae. The lymphatics here are seen to send out protoplasmic processes which, somewhat like an amoeba, actively take into the interior of the lymphatic red blood-cells accidentally forced from the blood-capiUaries into the tissue-spaces.
The mode of passage of leucocytes into or out of the lymphatics offers no such difiiculties as that of the fluids, for they are able, through their power of amoeboid movement, to pass independently through the endothelium — a process first directly observed by Cohnheim.
1. The Extent and Chabacter of Lymphatic Capillaries
The skin over the entire surface of the body is richly provided with lymphatic capiUariea. They form two sets of plexuses in the dermis, a superficial and a deep. The superficial set sends out bhnd cul-de-sacs into the dermal papillae. The richest skin plexuses are found in the scrotum, the palms of the hand and palmar side of the fingers and in the soles of the feet and plantar side of the toes. In the loose subcutaneous fascia, according to Teichmann, there are present only the larger collecting vessels, with no lymphatic capillaries. Lymphatic capillaries of the scrotum are shown in Fig. 547.
capillaries form a fairly regular ring which has been called by Teichmann a ciroulus lymphaticus.
At the various orifices of the body, the skin plexuses go over into the mucous plexuses, forming anastomoses with them. Tiiroughout the entire alimentary tract, including the nasal cavities, the lymphatic capillaries form extensive plexuses which are in many places divided into a superficial plexus in the mucosa and a deeper plexus in the submucosa. In portions provided with a peritoneal covering, there is a third rich subserous plexus. In the tongue and the small intestine the plexus in the mucosa sends out blind cul-de-sacs; in the tongue into the filiform papilla?; in the small intestine into the villi. Where muscle is present along the alimentary tract, the lymphatics pass between the muscle bundles, but form no plexuses around them.
The lining of the tracheal and bronchial passages is supplied with a double plexus of lymphatic capillaries, a mucous and a submucous set, which vary in richness according to the looseness of the tissue. In the smaller bronchi but a single layer of capillaries is present, and, according to Miller, no capillaries are present around the air cells. Plexuses surround the pul-
irregular plexuses.
The thyreoid gland contains lymphatic plexuses which lie in relation to the colloid-containing alveoli. Direct connection between the lymphatics and the alveoli has lately been described by Matzunaga, but this observation needs verification. The lymphatics are apparently concerned in the absorption of the colloidal secretion, for traces of it have been found in the lymphatics draining the gland.
nature of the capillaries in this gland is unknown.
The lymphatic capillaries of the liver are of great importance, for the lymph which flows from this organ forms a very considerable part of the total lymph which is collected into the thoracic duct. And yet very little is definitely knowm about the natm'e and distribution of the lymphatic capillaries in the interior of the organ. In the capsule there is a rich plexus, lying under the peritoneum, in which very large widenings have been described (called bj^ Teichmann "Lymphbehalter"). In the interior rich plexuses surround the branches of the hepatic artery and portal vein (fig. 549), and plexuses have been described accompanying the branches of the portal vein into the lobules.
Concerning the lymphatic capillaries of the pancreas Bartels notes briefly that they form richly branched plexuses in the interlobular connective tissues, which surround larger or smaller parts of whole lobules, not the single gland elements.
has been found provided with plexuses of lymphatics. In the bladder they form a rich plexus of irregular capillaries which lie immediately under the almost intraepithelial blood-capiUaries. They connect, through the muscular layer, with a subserous plexus. The lymphatic plexus of the urethra anastomoses \vith the capillaries of the base of the bladder, and in the male with those of the glans penis. The lymphatic capillaries of the ductus deferens and of the seminal vesicles have not been studied. In the prostate (Camineti) the lymphatics form rich plexuses surrounding the glands, which connect with a very wide meshed subcapsular plexus, surrounding the entire gland.
found the lymphatic capillaries going over into lacunse, without endothelium. This has been disputed by Tommasi and Gerster, who find, in the septa, capillaries with endothelial wall, which they consider the beginnings of the lymphatics.
In the female, lymphatic plexuses have been found in the mucosa of vagina and hymen, anastomosing with those of the vulva. In the uterus, capillaries in the mucosa are very difficult to demonstrate. Definite lymphatics, however, have been found passing through the muscularis, and under the peritoneum a rich subserous plexus of capillaries is present. In the pregnant uterus these subserous capillaries are much distended (Schick). The Fallopian tubes are provided v?itb lymphatics, but they have not been carefully described.
The ovary has a rich superficial lymphatic plexus. In the iaterior of the gland, according to His, the capUlaries form networks in the connective- tissue framework. In the tunica externa of the follicles there is a rich plexus.
The kidney has two sets of lymphatics, a superficial, capsular set, and a deep set. The capsular set is divided into two layers, one lying directly beneath the peritoneum made up of a wide meshed plexus, and the other in the fibrous capsule of the kidney, with finer capillaries and narrower meshes, which anastomose with the deeper capillaries. The lymphatic capillaries of the kidney parenchyma have recently been described by Kumita. He found rich plexuses in both cortex and medulla, surrounding the straight and convoluted tubules, the loops of Henle and the collecting tubules. He also found a plexus surrounding and accompanying the bloodvessels into the interior of the glomeruli.
The lymphatic capillaries of the adrenal have also been described recently by Kumita. His results agree with those of Stilling, who studied the lymphatics of the adrenal of horse, cow and calf. Like the kidney, the adrenal possesses a superficial and a deep set. The superficial set
is in two layers, as in the kidney, the outer lying in the looser tissue around the adrenal and the inner lying within and just under the capsule. The latter is made up of a rich lymphatic plexus, which anastomoses with the capillaries of the parenchyma. The parenchymatous lymphatics are present in the form of plexuses which surround the groups of cells.
In spite of numerous investigations, endothelial-lined lymphatics have not been definitely found in the central nervous system, or in the peripheral nerves. The subarachnoid and similar spaces, including the perineural spaces, do not form parts of the lymphatic system.
Rich plexuses of lymphatic capillaries are present in the tendons of muscles (SchweiggerSeidel and Ludwig). In muscles, themselves, the question of the presence of lymphatics has long been disputed, sometimes answered in the affirmative, more often in the negative. A recent study by Aagaard, however, would seem to place beyond doubt the presence of lymphatic capillaries in striated muscles. By long continued injection, he was able to find Ij'mphatics in the intramuscular portions of the tendons, which extended out among the muscle fibres themselves. He also found capillaries in the tongue musculature.
The heart is provided with a subpericardial plexus of lymphatic capillaries. A subendocardial plexus has also been described (Sappey, Rainer). Bock has recently found that there is an extremely rich lymphatic network throughout the substance of the heart. According to his description, the lymphatic capillaries are more numerous than the blood-capillaries. *~, kThe periosteum of bones is provided with a rich plexus of lymphatic capillaries. They are present in 'several layers, of which the outermost form the richest plexus. Lymphatic capillaries
have also been described accompanying the blood-vessels in the Haversian canals in bones (Rauber, Schwalbe, Budge). Nothing is known concerning the lymphatics of the bone marrow. Cartilage lacks both blood and lymphatic capillaries.
The capsular membranes of joints are richly provided with lymphatic capillaries (Tillmanns) . They are arranged in two layers — an inner layer made up of a rich plexus of wide capillaries, lying just outside the subendothelial blood-capillaries, and an outer layer, consisting of a rich plexus in the subsynovial tissue. The lymphatic capillaries have no open connection with the joint cavity.
The membranes suiTounding the pleural, pericardial and peritoneal cavities are richly supplied with lymphatic capillaries, which form here thick plexuses outside the endotheUum. These plexuses are usually described with the underlying organ, as the subserous lymphatic capillaries of the intestine, etc. In the central tendon of the diaphragm the subperitoneal lymphatics are extremely rich. They widen out here to form very large endotheUal-lined cavities which, in the spaces between the connective-tissue bundles, lie directly in contact with the peritoneal epithelium. The existence of open connections between these capillaries and the peritoneal and pleural surfaces (the "stomata" of von Recklinghausen) has recently been disproven. The capillaries on the two surfaces of the central tendon communicate freely with one another.
The lymph which enters the lymphatic capillaries passes over into collecting vessels (ducts), which carry it through the lymph-glands (nodes) to the large veins at the base of the neck. The lymph-vessels course in the loose subcutaneous tissues, in the connective tissues between muscles and organs, often accompanying the arteries and veins, sometimes forming networks around them. An idea of their arrangement can be best obtained by glancing at the illustrations of the lymphatics of special regions. In general they are made up of numerous long, narrow vessels, rarely more than half or three-fourths of a millimetre in diameter, which occasionally communicate with one another, and which radiate toward groups of lymph-glands placed in certain definite regions. In the lymph-glands the afferent lymph-vessels break up into capillaries, which again collect into efferent vessels. Several of these efferents from each lymph-gland may pass to a second lymph-gland, where they undergo a second widening into capillaries. In this way the lymph, passing through one, two, three or more lymph-nodes in succession, eventually reaches the thoracic duct, or one of the short ducts, all of which empty into the large veins at the base of the neck. The thoracic duct, which receives, at its lower end, the lymph from the lower half of the body, is the only lymphatic vessel which attains any considerable size (four to six millimetres in diameter) and is usually the only one large enough to be seen readily without injection.
In structure the lymphatic vessels much resemble the veins. They possess an intima, a media and an adventitia, although the line of demarcation between the different layers is not sharp. In the thoracic duct, the endothelium of the intima is succeeded by a delicate layer of fibres, mainly elastic; outside of this is the media, made up mainly of circular smooth musclecells, interspersed with elastic and connective-tissue fibres; then follows a layer of coarse elastic and connective-tissue fibres, which is succeeded by the adventitia, containing longitudinal and transverse bundles of smooth muscle-ceUs, as well as blood-vessels and nerves. The other lymphatic vessels possess the three layers, which, however, toward the capillaries, grow thinner, and eventually reach a stage in which, outside the endothehum, there are found only single musoleceUs, or muscle-ceUs in groups of two or three.
The lymphatic vessels are characterised by their great richness in valves, which are present throughout their entire course, from their beginnings in the capillary region to their openings into the veins of the neck. The valves are bi- or tri-cuspid, and are always arranged so as to prevent the flow of lymph back to the capillaries. They thus aid indirectly in the movement of the lymph, in that any external pressure on the vessels must always force the lymph onward.
Nerves of lymphatic vessels. — That the thoracic duct and the smaller lymphatic vessels are provided with nerves has been shown by several observers. According to Kytmanoff (in dogs) the nerves to the lymphatics are mainly non-medullated, and are both motor and sensory They form four sets of plexuses — adventitial, supramuscular, intermuscular and subendotheUal. Sensory nerve-endings (fig. 550) are found in adventitia and media, in the form of free-ending threads, and bush-like endings. Motor endings are present in connection with the smooth muscle cells of the media. In the intima there is a plexus of extremely fine varicose threads. The physiological action of the nerves supplying the receptaculum chyli has been tested by Camus and Gley who found in dogs a dilatation of the receptaculum as the result of electrical stimulation of the splanchnic nerve.
Movement of the lymph. — It has been estimated (Ludwig) that the amount of lymph which passes through the lymphatic ducts of a dog aggregates, during the twenty-four hours, one-third the body-weight. In the thoracic duct the lymph is under a sufficient pressure to burst the duct behind a ligature. In the absence of any especial propulsive organ, such as the heart for the blood-circulation, what are the forces which move the lymph? There must be recognised primary and accessory forces. As accessory forces there are the movement of the muscles and the
LYMPHATIC VESSELS
general pressure of the organs on the lymph-ducts. Since these are provided with valves, all preventing the lymph from flowing backward, any such pressure causes the lymph to move onward. As accessory agents must also be reckoned the smooth muscle and elastic tissue which is present in the walls of the lymph-vessels and in the lymph-gland. That these forces, however, are not primary is shown by numerous facts. There is an active circulation in the lymphatics of
Fig. 650. — A. The Adventitial and SuPKA-MusctrLAR Nerve Plexuses, together with Sensory Endings in the Thoracic Duct of a Dog. (Methylene-blue method.) B. Nerve-fibres on the Endothelium op a Lymphatic Capillary of a Dog. (After Kytmanoff.)
embryos long before valves develop. In many lower animals no valves develop save at the entrance of the lymphatics to the veins. That neither valves nor muscular movements are essential is shown by the fact that, in the tails of frog larvae, where no valves are present and where the muscle movements have been completely paralysed by an anesthetic, the circulartion of lymph continues unchecked.
process be a filtration and diffusion — -in which case the causes would he in the pressure and molecular condition of the tissue fluid outside the lymphatic — or whether it be an active secretion by the endothelium — in which case the driving force would be this secretory power of the endothelium.
3. THE LYMPHOID ORGANS
Closely associated with the lymphatic capillaries and vessels is a group of glandular structures known as lymphoid organs. They consist, essentially, of groups of round lymphoid cells, lying in a meshwork of reticulum fibres, and having often a definite relationship to the blood or lymph vessels.
The group of lymphoid organs includes, in addition to the lymph-glands [lymphoglandulse] or lymph-nodes, which are particularly related to the lymphatic vessels, the spleen, thymus and bone-marrow, which are also largely made up of lymphoid tissue. The spleen and thymus, however, are considered separately with the Ductless Glands.
In their most simple form, the lymphoid organs form mere irregular accumulations or patches of lymphoid cells, whioh^iave been termed lymphoid infiltrations. Such patches are frequent in mucous membranes especially along the intestinal tract (fig. 549) and the air-passages in the lungs.
Larger accumulations of lymphoid cells produce definite round nodules, which may occur singly, as solitary follicles or in groups, as aggregated follicles (Peyer's patches) (fig. 548). In the sohtary foLhcle the lymphoid ceSs are arranged concentrically, with a region in the centre where the cells are less closely packed together. This is called the germinal centre, and contains numerous cells undergoing mitotic division. The sohtary folhole contains blood-capiUaries. Lymph-capiUaries, however, do not enter the follicle but form a rich plexus about it.
The lymph-glands or nodes (fig. 551) are larger lymphoid structures, which are developed along the course of the lymph-vessels. They vary much in size, shape, and colour, and may occur singly or in small or large groups. The size varies from the size of a pin-head to that of an oUve, or larger. In skape'they may be spherical, oval, or flattened on one or more sides, according to their relations to other organs. Each gland has an indentation or hilus, where the arteries enter, and where the veins and efferent ducts emerge. Their colour depends upon position and state of function. The glands along the respiratory tract are black, due to the presence of carbon granules. The mesenteric glands are milk-white during digestion, and other nodes are pale and translucent when their sinuses are filled with fluid, and pink or even red when red-blood
The lymphoid elements (fiji. .551) are arranged as follicles and as cell-strings. The follicles lie around the circumference of the gland, and form the cortex [substantia corticalis]. The cellstrings or meduUary cords are irregular cords of cells which extend from the follicles through the central or medullary portion [substantia medullaris] of the gland. The follicles and medullary cords are made up, as are the solitary follicles, of round lymphoid cells.
The lymphatic vessels (tig. 551) enter the lymph-gland as several vasa afferentia, and leave it, at the hilus, as the vasa efferentia. The vasa afferentia spread out in the cortical portion of the gland into an extremely rich plexus of wide capillaries which surround the follicles, forming the peripheral sinus. The capillaries do not enter the follicle. This plexus continues, around the foUicles, into the medullary portion where it forms again a rich plexus, the medullary sinus, in the spaces around the meduUary cords (fig. 552). At the hilus the medullary capillaries collect into larger vessels and emerge as the vasa efferentia.
The supporting structures consist of a fibrous capsule surrounding the gland, from which trabecula3 or septa pass in, around and between the foUicles and cords. From the septa, a fine reticulum passes into the foUicles and cords, where it forms a rich dense meshwork, in the interstices of which lie the Ij'mphoid cells. The capsule and trabeculse are made up of white fibres, elastic fibres and smooth muscle-fibres.
into ihe meduUary cords.
The enormous widening of the lymph-stream in the lymph-node from the vasa afferentia to the capillaries — like a brook widening out into a pond — causes a very great diminution in the rate of flow of the lymph. Thus there is present in the gland a very slowly moving stream of lymph, which is separated from the lymphoid tissue outside by a single layer of flattened endotheh'al cells. There is thus possible an easy interchange of substances, and an opportunity for the passage, through the endothelium, of wandering cells. While the entire mode of functioning of the lymph-gland is not clear, it is known that lymphocytes, formed here, enter the lymph-stream, and that substances such as, for instance, carbon granules, or leucocytes laden with bacteria, are checked in their course by the lymph-gland.
Arrangement. — The lymph-glands are so arranged throughout the body that all the lymph which enters the lymphatic capillaries must pass through one or more lymph-glands on its way to the veins.
It is possible that this rule may have exceptions, although none have yet been definitely proved. Thus, some of the small lymphatics which join the thoracic duct may enter it without having passed through a gland. Moreover, there is often found (fig. 551) a direct anastomosis between an afferent and an efferent lymphatic vessel.
Most of the glands are collected in certain regions, where they form centers toward which the lymphatic vessels radiate. Such groups are termed regional glands. The glands forming such a group are connected with one another by numerous anastomoses, which are termed lymphatic plexuses [plexus lymphatici]. In addition to the regional glands there are many isolated glands which lie along the course of the lymph-vessels, and through which pass the vessels draining a much more limited capillary area. Such glands are termed intercalated glands.
Our knowledge of the lymphatic system has been very greatly increased during the past ten years by studies on its mode of development. Previous to 1902 nothing definite was known about the primary development or the mode of growth of the lymphatic system. It was concluded by some (Budge, GuUard and Saxer) that the lymphatics arise from undifferentiated mesenchyme cells; Ranvier believed that they arise from veins by budding of the endothelium; while Sala described them as arising partly from the mesenchyme and partly from venous endothelium.
Regarding the mode of growth and spreading of the lymphatics, various theories were likewise held. Kolliker, His, Goethe and, later, Sala held that growth takes place by the successive addition of mesenchyme cells; Langer, Rouget, and Ranvier maintained that growth takes place by sprouting of the endothelium (fig. 553). S. Mayer thought that new lymphatics are derived from transformed blood-capillaries.
Miss Sabin in 1902 gave the first clear picture of the mode of origin and growth of the lymphatic system, and our present knowledge is largely based upon her discoveries. She showed by injections of embryo pigs that the lymphatics of the skin appear first in four regions of the body — two on each side at the base of the neck, and two in the inguinal region — in the form of sacs which are connected with the veins. From these four regions the lymphatics spread out step by step over the skin of the entire body, in the form of a richly anastomosing capillary plexus. Since the publication of Miss Sabin's paper, numerous studies have been made on the mode of development of lymphatics in many different animals, including man. The results of these studies indicate that the lymphatic endothelium first appears in the form of buddings-out from the veins in certain well-defined regions of the embryo. As to the exact manner of this primary origin views differ. Miss Sabin, in her first paper, held that it arises by budding from the veins. F. T. Lewis held that it is formed by the transformation of plexuses of blood-capillaries. This view was accepted by Miss Sabin, and verified by Huntington and McClure. Stromsten recuiTi'd to Sala's view that the first lymphatic endothehum arises in part from venous endothelium, and in part from the mesenchyme cells. Hoyer and his pupila find that the first lymphatics arise as buds from the veins. This has also been found (1912) by E. R. and E. L. Clark in chick embryos.
Thus far six regions have been found, in which lymphatics develop from the veins — in the neck, on each side, at the angle formed by the internal jugular and subclavian veins; in the pelvis, on each side, along the iliac veins; and two unpaired sets in the region of the renal veins, one ventral to the aorta, the mesenteric, and one dorsal to the aorta, retroperitoneal. In these six regions the lymphatics soon coalesce to form large sacs, the jugular, iliac, mesenteric and retroperitoneal. The sacs are later broken up into the primary sets of lymph-nodes. The receptaculum chyli develops in the region of the retroperitoneal sac.
From these primary anlages derived from the veins the lymphatics spread out into the various organs and tissues of the body. The cutaneous lymphatics spread out from the two jugular and two iliac regions (Sabin), the lymphatics of the intestine from the mesenteric sac (Heuer).
The method by which this extension of the primary lymphatics occurs is still in dispute, but there seems to be conclusive evidence that it takes place by the sprouting of the endothehum (fig. 553) ; that the endothehum of the lymphatics, derived from the veins, is a specific, independent tissue, and that all new lymphatic endothehum is formed from lymphatic endothehum,
work of Sabin, MacCaUum, Hoyer and his pupils and E. R. Clark.
On the other hand, F. T. Lewis has suggested that the spreading of lymphatics occurs by the transformation of blood-vessels into lymphatics; while Huntington and McClure and their pupils maintain that it occurs by the continued transformation of mesenchyme cells.
The lymphatics growing from the various primary centres meet and anastomose with one another, and gradually lose aU connections with the veins save those at the base of the neck Sylvester has found, however, that in South American monkeys the connections with the veins in the region of the renal veins are maintained in the adult. Valves do not appear in the lymphatic vessels until quite late, in human embryos about 5 or 6 cm. long. (Sabin.)
The lymphatic nodes do not make their appearance until the system of vessels is well established. They are at first represented by masses of lymphoid tissue in the meshes of a lymphatic network. Later the lymphoid mass breaks up into smaller portions, into which the blood-vessels and branches from the surrounding network penetrate; and each mass, together
The lymphatics are injected and the sprouts are both single cells and clumps of cells.
with the portions of the network surrounding it, becomes enclosed in a connective-tissue capsule. The original lymphoid tissue becomes transformed into the medullary cords and cortical nodules of the node, while the enclosing lymphatic capillaries form its peripheral lymph-sinus.
The earhest nodes appear in the places occupied by the primary Ij'mphatic plexuses or sacs (Miss Sabin, F. T. Lewis, JoUy), and have been termed the "primary nodes" (Miss Sabin). Secondary and tertiary sets of nodes develop later at places of confluence of many Ivmohatics (cf. A. H. Clark.) • ^ f ^^
Regeneration and new growth of lymphatic vessels and glands. — While blood-vessels are known to possess throughout life the capacity for regeneration and new growth, this process in lymph-vessels has been very little studied. Yet enough has been learned from the work of Coffin and Evans to justify the statement that lymphatic vessels also possess the capacityFfor new growth. Evans made the interesting observation that lymphatic vessels grow into a tumor of connective-tissue origin (a round-celled sarcoma), while they fail to grow into a tumor of epithelial origin (an experimentally-produced peritoneal carcinoma in mice).
The question as to whether lymph-glands may form anew is not yet entirely settled. The study of the problem is extremely difficult, because very small lymph-nodes may be normally present in a csrfcain region, yet they may escape observation untQ they become hypertrophied under certain conditions. A. W. Meyer in a careful experimental study found no evidence of new-formation of lymph glands. On the other hand, there is considerable evidence for the newformation of lymph-glands under pathological conditions.
The haemolymph nodes. — In addition to the ordinary lymph-nodes, there occur along the course of certain veins small nodes which are either red or brown in colour, according to their state of functional activity. These have been termed haemolymph nodes. The red nodes closely resemble in structure an ordinary lymph-node, except that the sinuses are filled with blood, while the brown nodes show not blood, but blood pigment, both free in the sinuses and in the phagocytic cells of the sinuses. In certain respects these nodes resemble the spleen, there being a reduction of the medullary cords and an increase in the amount of the sinuses, which resemble those of the spleen-pulp rather than the more open lymphatic sinuses; and their trabeculae are also like those of the spleen in having numerous smooth muscle-cells. Some of these hsemolymph nodes have lymphatic
A difficult point in connection with the structure of the hfemolymph nodes is the relation of the blood-sinuses to the blood-vessels. The greater weight of evidence seems to favour the view that the sinuses are connected with the veins rather than that the arteries open directly into them, although one observer fails to find any connection between the blood-vessels and the central sinus (Schumacher). In fig. 554 is shown a hsemolymph node in the neck of a pig 24.5 cm. long. This stage marks the first appearance of the hsemal node in the neck, and shows the node in its simplest form, the foUicle and its peripheral blood-sinus (Miss Sabin).
There are wide variations in the distribution and number of the haemolymph nodes; indeed sufficient observations have not yet been made to determine their complete distribution. They have been divided into three groups, the prsevertebral, the renal, and the splenic. In one subject, in which they were very numerous, they occurred at the root of the lung, near the bronchi, and bronchial vessels, a few near the oesophagus, a continuous praevertebral chain in the abdomen extending from the diaphragm to the upper two or three sacral vertebra, as well as a few along the ccefiac axis and its branches, the superior mesenteric, renal, and iliac vessels (Lewis).
Schumacher, from a study of lymph-glands and haemolymph glands of various stages, concludes that the haemolymph glands are not to be considered as organs sui generis, but that they represent rudimentary forms of ordinary lymph-glands, which have lost their connections with the lymphatic vessels. Further investigations are needed to clear up this subject.
The lymphatics of the head and neck may be divided into two sets. One set is superficial, draining the entire skin sin-face, and has its nodes, for the most part, in the neck, the principal group lying along the external jugular vein. The other set is deeper and drains the mucous membrane of the upper part of the digestive and respiratory tracts, together with the deep organs, such as the thyreoid gland and the tendons of the muscles. The nodes of this set are deeply placed, being situated along the carotid arteries, with outlying retro-pharyngeal nodes.
Lymph-nodes appear first in the neck in the process of development. In the pig the first node to appear develops from the lymph heart, which is in the supraclavicular triangle behind the sterno-cleido-mastoid muscle. From here ducts grow across the muscle and give rise to a chain of nodes along the external jugular vein. This chain is to be considered as the main chain of superficial nodes in the neck. From it lymphatic vessels grow over the back of the head, the side of the head, the face, and the front of the neck, and in their course groups of secondary nodes develop. The nodes of the main chain are known as the superficial cervical nodes, and are from four to six in number. The secondary groups are — (1) the occipital; (2) the posterior auricular; (3) the anterior auricular; (4) the parotid; (5) the submaxillary, with the facial as a tertiary set, and (6) the submental.
1. The occipital nodes [lymphoglandulse occipitales]. — The lymphatics of the skin of the back of the head collect into a few trunks that either empty into from one to three small nodes near the occipital insertion of the semispinalis capitis muscle, or pass by the secondary group and empty directly into the upper nodes of the main superficial cervical chain (fig. 555).
2. The posterior auricular nodes [Igl. auriculares posteriores]. — A portion of the temporal part of the scalp, together with the posterior surface of the ear, except the lobule, and the posterior surface of the external auditory meatus, drain into two small nodes on the insertion of the sterno-cleido-mastoid muscle. The efferent vessels of these nodes pass to the upper part of the superficial cervical chain.
3. The anterior auricular nodes [Igl. auriculares anteriores] are few innumber — from one to three — and are situated immediately in front of the tragus of the ear. They receive vessels from the anterior surface of the auricle and the external auditory meatus, from the integument of the temporal region and the lateral portion of the eyelids. Their efferents pass to the parotid and superior deep cervical nodes.
4. The parotid nodes. — The parotid group of nodes is considerably larger than the two preceding, containing from ten to sixteen nodes, and the group drains a more complex area. It receives vessels from the adjacent surface of the external ear, the external auditory meatus, the skin of the temporal and frontal regions, and the eyelids and nose. The deeper nodes of this set receive vessels from the parotid gland.
In the embryo these nodes He in the pathway of the lymph- vessels that grow to the scalp; many of these vessels, however, pass the parotid group and empty into the superficial cervical chain. The nodes of the parotid group lie embedded in the substance of the parotid gland, and their efferents pass to the submaxillary and the superior superficial and deep cervical nodes.
chain of from three to six nodes, resting on the submaxillary (salivary) gland, along the inferior border of the mandible. They lie usually on the submaxillary gland, but may extend from the insertion of the anterior belly of the digastric to
the angle of the jaw. They are about the size of a pea, and the largest is near the point where the external maxillary (facial) artery crosses the mandible. The submaxillary nodes, together with the next group, the facial, drain a complex area,
THE FACIAL NODES
including not only skin, but mucous membrane. They receive lymph-vessels from the nose, cheek, upper lip, the external part of the lower lip, together with almost all those from the gums and teeth and from the anterior third of the lateral portions of the tongue. In agreement with the fact that these nodes, though lying superficially and draining the skin, drain also the mucous membrane, their vessels empty not only into the superficial cervical chain, but also into the deep carotid chain.
The facial nodes are evidently outlying nodes of the submaxillary group. They are in two main sets — (1) the supra-maxillary set, which consists of from one to thirteen nodes, resting on the mandible near the point where it is crossed by the external maxillary (facial) artery. (2) The buccinator set, lying on the
line connecting the lower margin of the ear and the angle of the jaw. Of these latter nodes, some lie near the point where the parotid duct perforates the buccinator muscle; the others are farther forward, between the external maxillary artery and the anterior facial vein. Additional nodes belonging to the group may occur near the nose and in the suborbital region. These facial nodes receive afferents from the outer surface of the nose, the lips, eyelids, cheek, temporal part of the face, the mucosa of the mouth, the teeth of the upper jaw, the gums, the tonsils, and the parotid gland. Their efferents pass to the submaxillary and parotid nodes.
6. The submental nodes [Igl. submentales], usually two in number, lie in the triangle bounded by the anterior bellies of the two digastric muscles and the hyoid bone (fig. 559). They are usually near the median line, and drain the skin of the chin, the skin and corresponding mucous membrane of the central part of the lower
vertex, from which vessels pass in various directions. From the frontal region a
Fig 557. — Lymphatic Nodes and Vessels of the Ear, Eyelids, Nose and Lips. Newborn child. P, parotid. M, submaxillary gland. Superolateral deep cervical lymph nodes are not labelled. (After Bartels.)
Posterior submaxillary lymph nodes
number of ducts pass downward and backward to the parotid nodes; those from the parietal and temporal regions pass to the anterior auricular, parotid, and posterior auricular nodes; and those from the occipital region pass partly to the occipital nodes and partly to the superior deep cervical group, while a single large vessel descends along the posterior border of the sterno-mastoid muscle to terminate in one of the inferior deep cervical nodes.
The lymphatics of the eyelids and conjunctiva. — The capillary plexus of the eyelids and the conjunctiva is an abundant one, and at the free border of the eyelids becomes extremely close. The lymphatics from the lateral three-fourths of the lids pass to the anterior auricular and parotid groups of nodes, while those from the medial one-fourth pass obliquely across the cheek with the facial vein to terminate in the facial and submaxillary nodes (figs. 556, 557, 561).
The lymphatics of the nose. — The lymphatics of the nose (fig. 556) form a network which is coarse at the root of the organ, but dense over the alar region. The vessels run in three sets — (1) one set passing over the eye to the parotid nodes; (2) a set passing under the eye to the same nodes; and (3) the most important
group, consisting of from six to ten trunlts, passing to the facial and submaxillary nodes. There are some anastomoses between the capillaries of the skin and those of the mucous membrane of the nose.
The lymphatics of theUps (fig. 559). — -The capillary plexuses of the skin and mucous membrane are continuous at the free border of the lips. The vessels of the upper lip, of which there are about four on each side, pass to the submaxillary
the same is true of the submucous vessels of the lower lip. The subcutaneous vessels, on the other hand, passing to the submental nodes, anastomose freely, an important fact in connection withthe extension of cancer of the lower lip.
The lymphatics of the auricle and external auditory meatus. — The lymphatic plexus in the auricle, external auditory meatus, and the outer side of the tympanic membrane is an abundant one. An anastomosis has been described between a scanty plexus on the inner side of the tympanic membrane and the plexus on the outside. The collecting vessels pass to three sets of nodes: — (1) those from the external and internal surface of the auricle and the posterior part of the external auditory meatus pass to the posterior auricular nodes; (2) those from the lobule, the helix, a part of the concha and the outer portion of the external auditory meatus pass to the inferior auricular and superficial cervical chain; some of the vessels from the first and second areas also run to the deep cervical group; (3) an anterior group from the tragus and part of the external auditory meatus consisting of from four to six trunks, pass to the anterior auricular nodes, which are connected with the parotid nodes.
The deep cervical chain is the largest mass of nodes in the neck. It consists of from fifteen to thirty nodes, which lie along the entire course of the carotid artery and internal jugular vein. This chain receives vessels from all the superficial nodes, also directly from the skin, as well as from the entire mucous membrane of the respiratory and alimentary tracts in the head and neck. Thus it drains both the superficial and the deep structures.
For convenience of description this long chain, though usually continuous, is divided into two groups — (1) a superior group, lying above the level at which the omo-hyoid muscle crosses the carotid artery, and (2) an inferior or supra-clavicular group, lying below that level.
(1) The superior deep cervical nodes [Igl. cervicales profundae superiores]. — This group of nodes extends from the tip of the mastoid process to the level at which the omo-hyoid muscle crosses the common carotid artery. The dorsal and smaller nodes of the chain lie on the splenius, levator scapulae, and scalene muscles. They drain the skin of the back part of the head, both indirectly and directly, and receive (1) efferents from the occipital and posterior auricular nodes, (2) a large vessel from the skin of the occipital part of the scalp, (3) some trunks from the auricle, and (4) cutaneous and muscular vessels from the neck.
The ventral nodes of the chain lie on the internal jugular vein. They drain the face both directly and indirectly, as well as the deeper structures of the head and neck. They show especially well in fig. 563 in connection with the tongue.
(2) The inferior deep cervical [Igl. cervicales profundse inferiores] or supraclavicular nodes lie in the supra-clavicular triangle. In the upper part of the triangle the nodes rest on the splenius, the levator scapulae, and the scalene muscles, while at the base of the triangle they are related to the subclavian artery and the nerves of the brachial plexus. They drain a wide area, receiving vessels from the head, neck, arm, and thoracic wall. They are connected with the superior deep cervical chain, and receive afferents from the axillary nodes, and, in addition, they receive vessels directly from the back of the scalp, from the skin of the arm, and from the pectoral region. Thus it will be seen that a large part of the lymph of the head and neck, as well as some from the arm and thorax, passes through these nodes. Their efferents unite to form the jugular trunk, which ends at the junction of the internal jugular and subclavian veins.
The lymphatics of the brain. — It is now recognised that there are no lymphatics in the brain and cord, so that the function of absorption must be accomphshed by means of the veins. There is an abundant exudation of lymph around the nervous system into the subdural space, which is connected with the central
LYMPHATICS OF THE MOUTH
canal of the nervous system, and which is to be considered as a zone in which the tissue-spaces are especially large. Along the arteries of the brain the adventitia is loose and open, possessing tissue-spaces which have received the confusing name of perivascular lymphatics. It would be better to name them perivascular tissuespaces.
The lymphatics of the eye. — No lymphatic vessels have as yet been discovered either in the eyeball or in the orbit. In both, however, there are abundant tissuespaces, the most noteworthy of the orbit being the interfascial space (space of Tenon), which communicates by a space between the optic nerve and its sheath with the subarachnoid spaces of the cranial cavity. In the eyeball the tissuespaces are abundant, even if the vitreous and aqueous chamber be omitted from the category. Numerous spaces exist in the chorioid coat, especially in the lamina supra-chorioidea, and in the sclerotic, both sets communicating by perivascular spaces surrounding the venae vorticosae with the interfascial space. In the cornea there are abundant lacunae, united by their anastomosing canaliculi, to form a network of lymph-spaces which come into close relation with the conjunctival lymphatics at the corneal margin.
Internal jugular chain
The conjunctiva, being a portion of the integument, does possess lymphatic vessels ffig. 562), arranged in a double network whose collecting vessels accompany those of the eyelids, and terminate with them in the submaxillary, anterior auricular, and parotid nodes.
The Lymphatics of the Digestive Tract in the Head and Neck
The lymphatics of the gums. — ^The lymphatics from the mucous membrane of the gums pass to the submaxillary nodes. The capillary plexus is abundant; the collecting vessels arise from it on the inner surface of the gum, and pass between the teeth to reach a common semicircular collecting vessel on the outer surface. Lymphatics have recently been demonstrated in the pulp of the tooth (Schweitzer).
The lymphatics of the tongue. — -There is a rich lymphatic plexus throughout the entire extent of the submucosa of the tongue, but that portion lying in the basal part of the tongue seems to be more or less independent of the rest. According to Aagaard the tongue muscles are provided with lymphatics which are drained by the ducts of the submucosal plexuses. There are four groups of collecting vessels — (1) apical; (2) marginal; (3) basal; and (4) central.
(1) The apical vessels are usually four in number, two on each side. One pair perforates the mylo-hyoid muscle and ends in a supra-hyoid median node, while the other pair pass to the deep cervical chain. The latter are long, slender vessels, which run along the frenum of the tongue to the surface of the mylo-hyoid muscle, cross the hj'oid bone just behind the pulley of the digastric, and then run downward in the neck to a node of the deep cervical chain, just
deep cervical nodes, a part of them passing external to the sublingual gland, while the larger number pass internal to it. There is one large and constant node at the point where the digastric muscle crosses the jugular vein, to which a large number of the vessels converge.
LYMPHATICS OF NASAL CAVITIES
(3) The hasal vessels are seven or eight in number, and drain the basal portion of the tongue. Some end in the large node just mentioned, while others run backward close to the median line, where they anastomose, as far as the glosso-epiglottidean fold, when they separate and join the tonsillar vessels to pass outward to the superior deep cervical nodes.
(4) The central vessels, arising from the central portion of the tongue, pass backward in the median line on the ventral surface of the tongue. They lie upon the mylo-hyoid muscle, cross the hyoid bone, and end in the superior deep cervical chain.
The lymphatics of the palate. — The lymphatics from the palate pass to the deep cervical chain. The trunks from the hard palate run in the submucosa as far as the last molar tooth, where they pass in front of the anterior pillars of the fauces and end in the superior deep cervical nodes beneath the digastric muscle. In the soft palate the capillary plexus is very rich, reaching a maximum in the uvula. From the inferior surface of the soft palate and the pillars of the fauces vessels pass directly to the superior deep cervical chain, but some of the vessels
from the upper surface of the soft palate run forward with the pharyngeal vessels and end in the retro-pharyngeal nodes. It will be seen from fig. 564 that the retropharyngeal nodes are simply outlying nodes from the deep cervical chain.
The lymphatics of the pharynx. — As has just been stated, there are certain outlying nodes of the deep cervical chain which lie behind the phaiynx. They receive some of the ducts from the submucosa of the roof of the pharynx, but many of the pharyngeal vessels pass by these nodes and end directly in the superior deep chain. The tonsil is especially rich in lymphatics, and its ducts, together with those from the middle and inferior portions of the pharynx, end in the superior deep cervical chain. The lymphatics of the Eustachian tube run to the lateral retro-pharyngeal lymph-nodes or, passing these, to the deep cervical nodes.
The lymphatics of the nasal cavities. — The mucous membrane of the nose contains a rich lymphatic plexus whose main ducts pass to the retro-pharyngeal nodes. An anterior set, however, anastomoses with the subcutaneous vessels, and through these their lymph is conveyed to the facial and submaxillary nodes. The posterior vessels run either to the deep cervical chain or to the retro-pharyngeal nodes. Key and Retzius have shown that an injection of the Ij^mphatics of the nose may be made by injecting the subarachnoid spaces at the base of the
NODES OF THE UPPER LIMB 719
The lymphatics of the larynx. — The larynx is, for the most part, drained by the deep cervical nodes, although its lymph may also pass through certain outlying nodes situated upon its ventral surface. The mucous membrane is divided into two zones by the ventricular folds, the mucous membrane of these structures possessing but a scanty lymphatic plexus. The vessels from the upper part of the lar3'nx, four or five in number, pass to the nodes of the superior deep cervical chain, situated near the digastric muscle; those from the lower part pass to the lower nodes of the same chain, some even descending as far as the supra-clavicular nodes. The lymphatics of the trachea pass, on each side, to the paratracheal and inferior deep cervical nodes.
The lymphatics of the thyreoid body. — The lymphatics of the thyreoid body pass either to the small nodes situated in front of the larynx and trachea, or to nodes of the deep cervical chain, a part of them ascending and a part descending.
It will thus have been seen that the lymphatics of the mucous membrane of the head and neck all end in the deep cervical chain of nodes or in the outlying nodes from it. Some of the vessels pass by the outlying nodes, but since the nodes of the chain are so closely connected, the lymph must pass through several nodes before entering the veins. The main tonsils, the numerous lingual and pharyngeal tonsils, together with small lymph-follicles in the submucosa of the respiratory tract, represent lymph-nodes in the capillary zone.
The lymph-nodes of the arm lie, for the most part, in the axilla, where thpre is a large group of nodes which receive almost the entire drainage of the arm and the thoracic wall. In addition, there is in the arm a set of outlying superficial nodes, the superficial cubital (supra-trochlear) , while small isolated nodes are often intercalated along the course of the deep lymphatic vessels which accompany the radial, ulnar, anterior interosseus and brachial arteries, the cephalic vein, and the deep cubital vessels.
(1) The antibrachial nodes are very small, pin-head sized nodes which are intercalated along the deep lymphatics which accompany the radial, ulnar, anterior and posterior interosseus arteries.
(3) The superficial cubital node [Igl. cubitales superficiales] (or supratrochlear) is situated three or four centimetres above the medial epicondyle of the humerus. It lies in the superficial fascia on the medial side of the basilic vein near the place where it passes through the deep fascia. It is usually single, but may be absent or represented by a chain of from two to five nodes. Its eflerents follow the basilic vein.
(4) The delto-pectoral nodes are very small intercalated nodes from one to three in number, and are situated in the groove between the deltoid and pectoral muscles. Their vessels follow the cephalic vein.
(5) The axillary nodes [Igl. axillares], from twelve to thirty-six in number, may be divided into groups according to the areas which they drain (fig. 566). In addition to the upper extremity, they receive lymphatic drainage from the thoracic walls, including dorsal, lateral and ventral (mammary) regions.
(1) The subclavian group consists of four or five nodes, situated in the apex of the axillary fossa. They receive the efferent vessels of all the other groups, and their efferent vessels in turn unite to form a single trunk, the subclavian, which empties into the thoracic duct on the left side and on the right side either into the vein directly or else after uniting with the jugular trunk. (See pp. 726-728.)
(2) The central group. A little lower along the axillary artery is a group of three to five nodes, which makes a second centre for the vessels of the other groups, and sends its efferents to the subclavian group. It will be clear from the figure that the separation of groups 1 and 2 is arbitrary.
(3) The brachial group. — This consists of four or five nodes, and, as its position toward the junction of the axillary and brachial arteries indicates, is the main station for the lymphatics of the arm proper. It receives almost all the superficial and deep lymphatics of the arm, and its efferents pass to the central and subclavian groups, although a few pass directly to the
to it there are usually two or three sjnall nodes on the dorsal surface of the scapula, in the groove which separates the teres major and minor. This group receives vessels from the dorsal surface of the thorax, aa well as from the arm, and its efferents pass to the brachial group.
(5) The anterior Jpeclmal'^group [Igl. peotorales]. — This group consists of four or five nodes which lie along the lower border of the peetorahs major and drain the mammary gland and front of the chest. Their efferent vessels pass to the central and subclavian groups.
(6) The posterior pectoral group [Igl. pectorales] consists of small nodes situated on the inner wall of the axiUa, along the course of the long thoracic artery. They receive afferents from the lateraljntegument of the thorax and drain into the nodes of the central group.
The superficial vessels. — The superficial lymphatic vessels of the arm course in two layers, the one quite subcutaneous, the other next the deep fascia, with frequent anastomoses between the two sets. The majority of these vessels remain superficial throughout the arm, but some of them pass through the deep fascia in the upper arm especially where the basilic vein pierces the deep fascia,
to join the deep lymphatics accompanying the brachial artery. The general distribution of the superficial lymphatics and their relations with the lymphnodes are shown in figs. 565 and 567.
The capillary plexus is most dense in the palmar sm-faces of the fingers, where the meshes are so fine that they can only be seen with a lens. On the dorsal surface of the fingers and hand the plexus is less dense. From the plexus on the palmar side of the fingers vessels come together at the base of the fingers where they pass dorsally to be joined by the dorsal vessels of the finger. They now follow two rather distinct curves: (1) those from the thumb and index finger and a part of the middle finger pass upward along the radial side of the forearm, com-se medially over the lower part of the biceps muscle, and empty into the axillary lymph-nodes. One or two vessels follow the cephalic vein and, after traversing the delto-peotoral node, pierce the costo-eoracoid membrane to enter the subclavian nodes, or pass over the clavicle into the inferior deep cervical nodes. (2) Those from the rest of the fingers course for a short stretch on the dorsum of the forearm, when they turn toward the ulnar side, wind around to the volar side and either continue superficially along the upper arm to the axillary nodes, or pass into the superficial cubital node, or, joining the efferents from these nodes, pass through the deep fascia to unite with the deep lymphatics. (3) A set of vessels from the palm of the hand passes upward along the volar side of the forearm. Anastomoses are frequent between these groups of lymphatic vessels, particularly in the cubital region.
correct) the muscles. They collect into vessels which, in general, accompany the arteries, in the forearm, the radial, ulnar, anterior and posterior interosseous, and in the arm the brachial. Above the elbow they are joined by numerous super-
Subcutaneous fat of the finger
ficiall lymphatic vessels including efferents from the superficial cubital nodes. Along their course in the forearm are intercalated small nodes (pin-head size), radial, ulnar, anterior and posterior interosseous (Mouchet) and deep cubital; and, in the arm, small brachial intercalated nodes. The deep vessels in the main enter the brachial group of axillary lymph-glands which lie behind the large vessels
The lymphatics of the shoulder-joint have recently been described by Tananesco. He finds a ring of lymphatics in the joint capsule, whose efferents, in the main, following the arteries, run to the central and subclavian groups of axillary nodes.
1. THE SUPERFICIAL LYMPHATIC VESSELS OF THE THORAX
The superficial lymphatics of the thorax pass almost exclusively to the axillary nodes, and may be regarded as forming three sets, a ventral, a lateral, and a dorsal. The ventral set drains the thoracic integument, which extends form the median line and the clavicle over to the lateral border of the chest, and includes the vessels of the mammary gland, which will, however, be described separately. The majority of the vessels from this area end in the anterior pectoral group of axillary nodes, a few, which arise beneath the clavicle, passing to the supraclavicular nodes, and a few perforating the intercostal spaces and ending in the chain of nodes along the internal mammary artery.
It has been shown that an injection into the subcutaneous plexus near the median line passes to the opposite side, and that, in addition to the anastomosis between the networks of the two sides of the thorax which this result manifests, there may also be a few collecting trunks crossing the median line, and, furthermore, anastomoses occur between the superficial networks of the anterior thoracic and abdominal walls. Thus while the main channel of lymphatic drainage is through the axiUa, there are minor accessory channels to (1) the supraclavicular nodes, (2) to the axilla of the opposite side, (3) to the internal mammary chain, and (4) in isolated cases even to the inguinal nodes. These accessory channels may become more open in cases of obstruction to the main channel.
The lateral set of superficial thoracic lymphatics is much less extensive than the anterior, and its collecting vessels pass upward to open into the posterior pectoral group of axillary nodes.
The lymphatic network over the peripheral portions of the mammary gland is like that of the rest of the thoracic wall. In the areola, however, the capillaries are far more abundant, forming a double subareolar plexus. The superficial plexus is so dense that its meshes can be seen only with a lens. The deeper plexus not only drains the superficial plexus, but receives the vessels from the mammary gland itself, and from it arise two large trunks, one from the inferior and one from the superior part of the plexus. These two vessels pass to one or two of the nodes belonging to the anterior pectoral group of axillary nodes. In addition there may be — (1) one or two vessels passing to the nodes along the axillary artery; (2) in rare cases a vessel passing directly to the subclavian nodes. There is also a definite channel from the medial margin of the gland to the internal mammary nodes, the ducts following the perforating branches of the internal mammary vessels, and it may be noted that the crossed anastomosis and that with the abdominal network, mentioned in connection with the superficial thoracic vessels, may, on occasions, serve as channels for the mammarj^ drainage.
There is also clinical evidence indicating that lymphatic vessels from the lower and medial aspect of the mammary gland may pass through the abdominal wall in the angle between the xiphoid process and the costal cartilages, establishing a communication with the lymphatics of the abdomen in the diaphragmatic region.
Lymphatics of the thoracic muscles. — The recent studies of Aagaard make it probable that muscles are provided with lymphatics. Whether his findings will be substantiated or not, however, it is unquestioned that lymphatic vessels course through the pectoral muscles — some passing to the axillary, others to the subclavian, and still others to the internal mammary chain of nodes. This would suffice to explain the fact that cancer of the breast may extend into and through the pectoral muscles.
The lymphatic nodes of the thoracic cavity may be divided into the parietal and the visceral. The parietal nodes are arranged in two sets, the internal mammary chain and the intercostal nodes (fig. 570) . Along the internal mammary artery are from four to sLx small nodes, [Igl. sternales] which receive ducts from the anterior thoracic and the upper part of the abdominal walls, from the anterior diaphragmatic nodes which drain the liver, and from the medial edge of the mammary gland. The efferent vessels usually unite with the vessels of the anterior mediastinal and bronchial nodes, to form the broncho-mediastinal trunk, which may join the thoracic duct on the left and the jugular or subclavian trunk on the right or may empty separately into the subclavian vein on both sides.
Vessels from network
The intercostal nodes [Igl. intercostales] lie along the intercostal vessels, near the heads of the ribs. There are usually one or two in each space, and occasiona,lly a node is placed where the perforating lateral artery is given off. They receive afferents from the deeper part of the thoracic wall and costal pleura. Their efferents enter the thoracic duct, those from the nodes of the lower four or five interspaces uniting usually to form a common duct on each side, but more marked on the left side, which descends to the receptaculum chyh.
The efferent lymph-vessels from the upper intercostal nodes often unite into common trunks which drain several interspaces, and which may pass through a large gland near the thoracic duct before emptying into it. Occasionally such collecting vessels from the right side cross the mid-Une behind the aorta to reach a large gland to the left of the aorta.
The visceral nodes of the thorax are arranged in three groups : — ■ 1. The anterior mediastinal nodes [Igl. mediastinales anteriores] are situated, as their name indicates, in the anterior mediastinum, and are arranged in an upper and a lower set. The upper set is situated upon the anterior surface of the arch of the aorta, and consists of eight or ten nodes, which receive afferents from the pericardium and the remains of the thymus gland. Their efferent vessels pass upward to join the broncho-mediastinal trunk. The lower set consists of from
three to six nodes, situated in the lower part of the mediastinum. They receive afferent ducts from the diaphragm, hence they are sometimes termed the diaphragmatic nodes, and also from the upper surface of the liver. Their efferents pass upward to open into the upper anterior mediastinal nodes.
2. The posterior mediastinal nodes [Igl. mediastinales posteriores] eight or ten in number, are situated along the thoracic aorta, and receive vessels from the mediastinal tissue and from the thoracic portion of the oesophagus. Their efferents open directly into the thoracic duct.
of each lung, those lying in the hilus being termed the pulmonary nodes, and others, according to their position, lateral tracheo-bronchial, inferior tracheobronchial (nodes of the bifurcation) and tracheal (paratracheal). Thej'' receive the drainage of the lower part of the trachea, the bronchi, the lungs, part of the oesophagus, and, to a small extent, the heart. Thek efferent vessels unite with those from the upper anterior mediastinal and internal mammarj^ nodes to form the broncho-mediastinal trunk.
In following the deep lymphatics of the thorax the course of development will be followed in describing first the thoracic duct and right lymphatic ducts, second the parietal vessels, and third the visceral vessels.
The Thoracic Duct
The thoracic duct [ductus thoracicus] (fig. 570), which is the main collecting duct of the lymphatic system, extends from the second lumbar vertebra along the spinal column and course of the aorta to the junction of the left internal jugular and subclavian veins. It receives all the Ij^mphatics below the diaphragm, and the deep lymphatics from the dorsal half of the chest wall; and also, when joined, near its cephalic end, by the left broncho-mediastinal, subclavian and jugular trunks, from the remainder of the left half of the body, above the diaphragm. At the caudal end the duct is formed usually by the union of three collecting ducts, one from each of the lumbar groups of nodes, and an unpaired intestinal
trunk. At its origin then is usu ilh i dil i1( d poition known as the receptaculum [cisterna chyli]. This usually endh opposite the bodj^ of the eleventh thoracic vertebra, and from here on the duct is from 4 to 6 mm. in diameter, until near its termination, where it is again wider.
In its cadual part, the duct lies dorsal to the aorta in the median line; it passes through the aortic opening in the diaphragm, and then inclines to the right and passes upward to about the fourth, fifth, or sixth thoracic vertebra, when it bends to the left and passes, continuing upward, over the apex of the left lung and the left subclavian artery, and in front of the root of the left vertebral artery and vein, and then curves downward to open into the left subclavian vein, close to its junction with the left internal jugular. The duct runs in the wall of the vein a short distance before ending.
Variations. — There is a wide range of variation from this usual course. The duct is frequently double throughout a part of its course, the two branches being connected by cross anastomoses, and finally uniting into a single trunk before joining the veins. It may be
multiple, or a single trunk may pass in front of the aorta instead of behind. In a few instances it has been found emptying into the right instead of the left subclavian vein. There is also a wide range of variation in the height to which the duct ascends in the neck before curving downward to the vein. As regards the termination of the thoracic duct, variations are also frequent; it may bifurcate and end as two ducts. It often connects with the lowermost part of the internal jugular, or the beginning of the innominate. According to Henle, there is one undoubted case reported of a thoracic duct ending in the azygos vein near the sixth thoracic vertebra, the duct being obliterated above this point. At the terminal bend the thoracic duct receives the jugular trunk from the neck; it may also receive the subclavian and the bronchomediastinal trunks, but it is more usual for these last two to open either separately or together into the subclavian.
Variations are extremely numerous in the region of the receptaculum. Severa lobservers state that, in the majority of cases in man, no definite receptaculum exists. Bartels found one in only 25 per cent, of the cases studied. Instead, there is present a widening of each of the two lumbar trunks, with several anastomoses between them (55 per cent., Bartels), or a widening of these two stems without anastomosis (5 per cent.), or a much elongated widening arising
trunks remain separate, the intestinal trunk joins the left one.
Development. — While the exact mode of its development is still in dispute, enough is agreed upon by the various investigators to explain most of the variations in the thoracic duct. In brief, it is known that the lymphatics start in the neck as a variable number of outgrowths from the veins in the region of the junction between the later internal jugular and subclavian veins. A variable number of these connections disappear, while the various combinations of one, two, three or four which are retained furnish the numerous variations in number and position of the ducts which empty into the vein in the adult. Thus the thoracic duct may have one, two or even three openings into the veins, while the jugular, subclavian and bronchomediastinal trunks may join the thoracic duct or may enter the veins separately or in various combinations.
It is also known that the upper part of the thoracic duct is at first bilateral, being formed by outgrowths from the primary plexus, which meet in a common plexus around the aorta. Normally the right portion of these connections disappears, so that the thoracic duct empties into the left subclavian vein. In exceptional cases, where it opens into the right subclavian vein, there have also been present variations in the large right arterial trunk. These conditions in all probability at a certain stage in development produced a greater resistance to the lymph stream in the left than in the right vessel causing it to become obliterated so that the right instead of the left became the permanent ending of the duct.
Most of the other variations — the frequent presence of longer or shorter doublings of the duct with anastomoses between the two parts, the numerous variations in the region of the receptaculum chyli — are easily explained by the fact that the duct and receptaculum pass through a stage in development in which they form richly anastomosing plexuses around the aorta.
The Right Tbbminal Collecting Ducts
On the right side the jugular, subclavian, and broncho-mediastinal trunks usually open separately into the subclavian vein, the orifices of the first two being near together. When the jugular and subclavian trunks unite, the common duct is termed the right lymphatic duct; this is a rare form, and it is still more rare for the three ducts to unite to form a common stem (fig. 572). These variations have the same explanation, embryologically, as was given for the corresponding variations on the left side.
As with the nodes, the deep lymphatic vessels of the thorax may be divided into a parietal and a visceral group. To the former group may be assigned the lymphatics of the intercostal spaces and those of the diaphragm.
The intercostal lymphatics form plexuses in each intercostal space, which receive lymph from the periosteum of the ribs and from the parietal pleura, and from which the drainage is either ventral or dorsal. From the dorsal half of each space the drainage is to the intercostal nodes, while from the ventral half it is toward the internal mammary nodes.
The lymphatics of the diaphragm. — There is an exceedingly rich plexus of capillaries both on the pleural and on the abdominal surface of the diaphragm, especially in the region of the central tendon, these plexuses lying in the subserous layers and being freely connected by vessels which perforate the muscle. There is, however, only slight communication between the plexuses of the right and left sides of the diaphragm. The vessels lie between the coarse muscle bundles, forming a very characteristic picture, in which the lymphatics stream outward radially, like the spokes of a wheel. The collecting vessels empty into three groups of small nodes on the convex surface. The ventral group lies ventral to the central tendon. Two or three nodes in the centre of this group receive
afferents from the liver and none from the diaphragm, but the rest receive vessels from the ventral sm'face of the diaphragm and the efferents of all pass to the lower set of anterior mediastinal nodes.
The dorsal group of four or five nodes is placed between the pillars of the diaphragm. The vessels from the lateral and dorsal groups pass to the posterior mediastinal nodes, and also to the upper coeliac nodes, which likewise receive the drainage from the dorsal part of the abdominal surface of the diaphragm.
the lungs, the heart, and the oesophagus.
The lymphatics of the thymus drain, according to Severeanu, into three sets of glands, an anterior, a ventral and a dorsal group. The anterior set, one gland on each side, lies lateral to the cephalic end of the thymus, and drains into the jugular or subclavian trunlc. The ventral set includes 4-6 of the anterior mediastinal lymph-glands.
The lymphatics of the lungs are arranged in two sets. A deep set takes its origin in plexuses which surround the terminal bronchi and follows the course of the bronchi, the pulmonar.y artery, and the pulmonary vein to the pulmonary nodes at the hilus, whence the stream passes to the main bronchial nodes (fig. 569), especially to those situated in the angle formed by the bifurcation of the trachea,
situated upon the surface of the lung beneath the visceral layer of the pleura.
According to Miller, who has studied the lymphatics of lung and pleura most carefully in dog and man, the only communications between the lymphatics of the pleura and the deep lymphatics oociu- around the veins which reach the pleural surface. These vessels are provided with valves so that the lymph stream passes, in them, toward the pleural surface. The collecting stems of the subpleural lymphatics pass independently to the pulmonary nodes.
Lymphatics of the heart. — The superficial (subepicardial) tymphatics of the heart collect to two main stems which accompany the main coronary vessels. The right stem accompanies the right coronary artery to its origin, passes on over the arch of the aorta and empties into one of the anterior mediastinal lymphnodes. The left stem, formed by two stems accompanying the circumflex and anterior descending branches of the coronary vein, passes behind the arch of the aorta to an anterior mediastinal lymph-gland. Two small subepicardial intercalated nodes have been described along these trunks.
The course of their efferent vessels has not yet been described.
The lymphatic vessels of the oesophagus, which will here be considered throughout its entire extent, cervical as well as thoracic, are arranged in two plexuses, one of which occurs in the mucosa and the other in the submucosa. The collecting vessels arising from the plexuses may be divided into three sets, of which the uppermost pass to outlying nodes belonging to the deep cervical chain, those from the thoracic portion of the tube pass to the bronchial and posterior mediastinal nodes, while those from its lowermost part pass to the superior gastric nodes (fig. 573).
D. THE LYMPHATICS OF THE ABDOMEN AND PELVIS
In the following section there will be described successively the lymphatic nodes of the abdomen and pelvis, the lymphatic vessels of the abdominal walls, and the visceral lymphatic vessels.
The lymphatics which connect directly with the thoracic duct, though complicated, may be described briefly by saying that they follow the aorta and its branches. In the abdomen there are four main chains along the aorta — (1) the left lumbar chain; (2) the right lumbar chain; (3) the pre-aortic chain; and (4) the post-aortic chain.
The right and left lumbar nodes [Igl. lumbales], form an almost continuous chain along the abdominal aorta, resting upon the psoas muscles, some of those on the right side being ventral and some dorsal to the inferior vena cava. They receive: — (1) the efferent lymphatics of the common ihac nodes, and hence drain the leg and external genitaha; (2) the efferent lymphatics that follow the lumbar arteries and hence drain the abdominal AvaU; (3) the efferents that follow the paired visceral aortic branches, namely, those from the kidneys, supra-renal, and internal reproductive organs. On the right side, the lymphatics from the reproductive organs pass to the nodes ventral to the vena cava — those of the abdominal walls pass to the dorsal set, while those from the kidney pass to both sets.
The efferent vessels of the lower lumbar nodes pass to higher ones and so on up the chain, the vessels from the uppermost nodes uniting to form a single lumbar trunk on each side. These trunks pass to the thoracic duct, forming two of the so-called trunks of origin of that vessel (fig. 571).
The pre-aortic nodes [lymphoglandulte coeliacEe] are arranged in three groups at the root of each of the three unpaired visceral branches of the aorta — the cceliac, the superior mesenteric, and the inferior mesenteric arteries. The cceliac nodes are from one to three in number, and are in reality parts of chains of nodes extending along the branches of the artery and constituting the hepatic, gastric, and splenic nodes. They drain the stomach, duodenum, liver, pancreas, and spleen.
LYMPHATICS OF ABDOMEN
The superior mesenteric group is larger, and is continuous with the mesenteric nodes lying in the root of the mesentery. This group drains the remainder of the small intestine, the CEecum and appendix, the ascending and transverse colons, and the pancreas.
The inferior mesenteric group usually has two nodes, one on either side of the artery. It drains the rectum and descending and sigmoid colons. All the nodes in the mesentery and intestinal walls may be considered as outlying nodes of the pre-aortic group. They will be studied in connection with the visceral lymphatics.
The inferior mesenteric nodes drain into the neighbouring lumbar nodes, and also directly upward to the superior mesenteric nodes, and then again to the cceliac nodes. From the last a single stem, the intestinal trunk, arises and passes either to the right lumbar trunk or directly to the thoracic duct, forming the third of the so-called trunks of origin of the duct.
iliac, the external iliac, and the hypogastric.
The common iliac nodes [Igl. iliacse], are in three groups (fig. 575). The external set consists of about two nodes, which are in reality a part of a continuous chain extending along the side of the aorta, common iliac, and external iliac arteries. A second set of two to four posterior nodes lies behind the artery. These two groups receive the efferent vessels of the external iliac and hypogastric chains. The internal set usually consists of two nodes which rest upon the promontory of the sacrum. They receive vessels from the sacral nodes, together with most of those from the pelvic viscera, namely, from the prostate, neck of the bladder, neck of the uterus, the vagina, and part of the rectum. The efferent lymphatic vessels of the common iliac nodes pass to the lumbar chain.
External iliac nodes. — These are likewise in three sets — -external, middle, and internal. The external chain consists of three or four nodes, the lowest one being behind the crural arch. They receive: — (1) some of the vessels of the superficial and deep inguinal nodes; (2) vessels from the glans or chtoris, which come tlirough the inguinal canal; (3) vessels from the part of the abdominal wall supplied by the deep epigastric and deep circumflex arteries, along which there may be a few outlying nodes — the epigastric nodes.
The middle chain consists of two or three nodes behind the artery. When there are three, the lowest is likewise near the crural arch. It receives vessels from the bladder, prostate, neck of the uterus, and upper portion of the vagina. The internal chain consists of three or four nodes, and is the continuation of the deep inguinal nodes. Its lowest nodes are likewise near the femoral ring, while the next node is large and constant, and usually lies within the pelvis. This chain
receives many vessels: — (1) from the superficial and deep inguinal nodes; (2) from the glans and clitoris through the femoral canal; (3) from the abdominal wall; (4) from the neighbourhood of the obturator vessels; (5) from the neck of the bladder, the prostate, and membranous part of the urethra; (6) from the hypogastric chain.
Thus, to sum up the nodes of the external iliac chains: — they are a part of a chain which includes the lumbar, common iliac, external iliac, and inguinal nodes. It will be noted that this extensive chain stops, for the most part, with the deep inguinal group. The external iliac nodes receive the efferents of the superficial and deep inguinal nodes; the middle and internal groups receive vessels from the pelvis. The efferent vessels of all the nodes in the chain pass to the higher nodes.
The hypogastric nodes [Igl. hypogastricse]. — ^These nodes are in groups near the origin of the branches of the hypogastric (internal iliac) artery. Thus they occur near the origin of the obturator, the uterine, or prostatic, the trunk of the
LYMPHATICS OF ALIMENTARY TRACT 733
inferior gluteal (sciatic) and pudic, the middle hjemorrhoidal, and the lateral sacral arteries. All the nodes are beneath the pelvic fascia, and are connected bynumerous anastomoses. They receive lymphatics from the structures supplied by the corresponding arteries, namely, from the pelvic viscera, the perineum, and the posterior surface of the thigh and gluteal region. Their efferent vessels pass partly to the middle group of the common iliac nodes, and partly to the posterior nodes of the same chain.
The sacral nodes [Igl. sacrales]. — These nodes, 5 or 6 in number, lie in the hollow of the sacrum, in or near the mid-line. They receive afferent vessels from rectum and prostate, and their efferents pass to the hypogastric and lumbar nodes.
The lymphatic vessels of the abdominal walls are arranged in two sets, one of which is subcutaneous and the other deep or aponeurotic. The subcutaneous vessels form a rich network through all the subcutaneous tissue of the abdomen, anastomosing above with the subcutaneous plexus of the thorax. The collecting vessels converge toward the inguinal region, those from the posterior wall curving forward along the crest of the ilium, and they all terminate in the superficial inguinal nodes.
The deep vessels drain along three principal lines. (1) A set of collecting vessels follows the line of the deep epigastric artery to terminate in the lower external iliac nodes; (2) a second set follows the deep circumflex iliac vessels to the same nodes; and (3) a third set follows the lumbar vessels to terminate in the nodes of the lumbar chain. A group of small epigastric nodes, which may be regarded as offsets from the iliac chain, occur on the lymph-vessels which accompany the deep epigastric vessels, not far from their termination, and a second less constant group of usually three small umbilical nodes occurs in the vicinity of the umbilicus in the network covering the posterior layer of the sheath of the rectus abdominis muscle.
The lymphatics to the viscera follow along the course of the arteries. At the point where the artery of an organ branches from the aorta there is a group of nodes which represents the main regional group, and a second chain of nodes extends along the artery. The final arrangement of nodes and ducts varies with each organ.
Though the lymphatics follow the blood-vessels, the lymphatic capillaries in the regions where their relations are known are separated from the vascular capillaries; in the intestinal villi, for example, the lymphatic capillaries are central, while the vascular capillary plexuses are peripheral. The relation of the lymphatic capillaries to the essential structures of each organ, that is to say, the arrangement of the lymphatics in the absorbing area, is not yet clear in many organs, and this is a point which can be worked out by tracing the development and gradual invasion of each organ by the lymphatics. The old theory of the origin of the lymphatics from the tissue-spaces made this problem most difficult of attack.
In almost all organs there is a peripheral or capsular lymphatic plexus, which anastomoses with the parietal lymphatics, these anastomoses being particularly well developed in the case of the liver. In addition there are one or two deep plexuses in the great majority of the organs which drain partly directly to their regional nodes and partly by way of the peripheral plexus.
The lymphatics of the mouth, pharynx, and oesophagus have already been described (pp. 715, 730). In general, throughout the abdominal part of the alimentary canal, the distribution of nodes is as follows: — (1) There are primary regional nodes situated at the roots of the arteries as they leave the aorta, that is to say, aroundthe coeliac and the superior and inferior mesenteric arteries; these
drain large segments of the intestine; (2) groups of definite and constant nodes placed along the branches of the arteries in the root of the mesentery; these drain a definite smaller segment of the intestine; (3) chains of nodes along the anastomotic loops of the arteries, close to the intestinal wall ; these are of the type called 'intercalated nodes'; (4) solitary or compound follicles, situated within the submucosa or capillary zone of the lymphatics.
What may be taken as the typical arrangement of the lymphatic vessels in the intestine may be seen in fig. 576. There are three zones in which the capillary plexuses are spread out, namely, in the subserosa, the submucosa, and the mucosa. There is an abundant plexus of large capillaries just beneath the serosa; inthe submucosa the plexus is also formed by large capillaries, while the mucosal plexus is finer. The lymph-foUicles lie in the zone of the mucosal plexus, and it is from this that the central chyle vessels of the villi arise. The collecting vessels are formed by the union of vessels from the submucous and subserous plexuses. They traverse the three sets of nodes just described.
The lymphatics of the stomach (fig. 577) . — The stomach differs from the rest of the alimentary canal in its blood-supply in having a ventral anastomotic loop, namely, that along the lesser curvature. Along this loop is the superior gastric chain [Igl. gastricse superiores] of nodes, lying between the folds of the lesser omentum, some of them being on the posterior surface of the stomach. This is the most important group of nodes draining the stomach, and it has been shown that the lymph-vessels from the pylorus run obliquely across the stomach to the main mass of nodes near the cardia, an important point in the surgery of the pylorus. The efferent vessels of the chain pass to the coeliac nodes. The vessels of the greater curvature pass to a group of inferior gastric nodes [Igl. gastricae inferiores], situated along the right gastro-epiploic artery, while those of the fundus follow the short gastric and left gastro-epiploic vessels to the nodes which lie along the splenic artery, both these sets of nodes also draining to the coeliac group. There is a zone half-way between the lesser and greater curvatures, in which the lymphatics are scanty. The lymphatics of the cardia connect with those of the oesophagus, and the mucosal plexus of the pylorus is continuous with that of the duodenum.
The lymphatics of the duodenum. — The lymphatics of the duodenum depart somewhat from the type, owing to its relations with the pancreas and the bileducts. The collecting vessels end: — (1) in nodes ventral to the pancreas, which follow the pancreatico-duodenal artery to the hepatic chain; (2) in nodes dorsal to the pancreas, which follow the superior mesenteric artery to the superior mesenteric nodes. There are anastomoses between the lymphatics of the duodenum and those of the pylorus, of the pancreas, and of the chain along the common bile-duct.
The lymphatics of the jejuno-ileum (fig. 578) have already served as the type of the arrangement of the intestinal lymphatics (see above). The mass of mesenteric nodes [Igl. mesentericse] to which the lymphatics of the small intestine pass is the largest and one of the most important in the body, its individual nodes numbering anywhere from 130 to 150.
The lymphatics of the ileo-caecal region. — The surgical importance of the lymph-nodes in connection with the appendix warrants a detailed description of them in which the observations of Broclel will be followed. The drainage of the caecum and appendix is along the ileo-colic artery, and is carried on by three sets of collecting vessels — (1) an anterior cajcal set, which generally pass through one or more outlying nodes before reaching the ileo-csecal mesenteric nodes; (2) a similar posterior set; and (3) an appendicular set, three to sLx in number, which usually pass directly to the ileo-csecal nodes. The appendix thus has an independent drainage into one or two ileo-c£ecal nodes, about 3 cm. above the ileum. The ileo-csecal chain drains through the mesenteric nodes to the superior mesenteric group (figs. 579, 580).
The lymphatics of the large intestine. — Along the ascending colon there are but few nodes on the terminal vascular arches, but the number increases along the transverse colon, especially at its two angles. These nodes, together with those along the descending and sigmoid colons, are termed the meso-colic nodes [Igl. mesocolicse], and they drain partly to the superior mesenteric and partly to the inferior mesenteric nodes, their efferents following the corresponding arteries.
of the descending colon are more scanty.
The lymphatics of the rectum and anus. — There are three lymphatic zones of the rectum and anus. (1) An inferior zone, corresponding to the anal integument, in which the capillary networks, both superficial and deep, are extremely abundant, and from which from three to five collecting vessels on either side pass to the inguinal region and end in the medial superficial inguinal nodes. (2) A
middle zone, corresponding with the transition zone of epithelium — that is, with the mucous membrane below the columns of Morgagni. Here the network is coarse, and has its meshes arranged vertically; its ducts drain partly into nodes situated along the inferior and middle hsemorrhoidal arteries, and partly pass to nodes in the meso-rectum, situated along the superior hsemorrhoidal artery and known as the ano-rectal nodes. (3) The superior zone corresponds to the remainder of the rectal mucous membrane, and contains a rich network whose collecting vessels pass to the ano-rectal glands, and thence along the superior hsemorrhoidal arteries to the inferior mesenteric nodes.
Lymphatics of the liver. — The lymphatic drainage of the liver is complicated and has great need of being entirely restudied from the standpoint of development. Its course is mainly to the coeliac nodes, but on the way it passes through a secondary group of three to six hepatic nodes [Igl. hepaticse], situated along the hepatic artery. Some of these nodes are along the horizontal part of the artery, parallel to the superior border of the pancreas, while the rest follow the artery in its vertical course along with the portal vein, and become continuous at the portal fissure with two distinct chains of nodes, one of which follows the hepatic artery and portal vein, and the other the cystic and common bile-ducts. These nodes are variable, but one constant node is at the junction of the cystic and hepatic ducts. A part of the drainage of the liver is also through the diaphragmatic nodes.
The superficial collecting lymph-vessels of the liver have been studied by Sappey. Those from the superior surface include three sets. From the dorsal part vessels pass through the diaphragm with the vena cava, and end in the adjacent posterior mediastinal nodes. Some of these vessels from the right lobe pass in the coronary ligament to the coeliac nodes, and some from the left lobe to the superior gastric nodes. The second set of vessels from the superior surface runs over the ventral border to the hepatic nodes situated in the portal fissure. The third and most important set arises near the falciform ligament, and passes
To inferior gastric node
partly dorsalward to the anterior mediastinal group of nodes on the upper surface of the diaphragm, and to the nodes around the vena cava, and partly ventralward to the hepatic nodes of the portal fissure.
Lymphatics of the pancreas. — The lymph-vessels which drain the pancreas fall, according to Bartels, into four groups: left, anterior (upper), right and posterior (lower). (1) The left group drain the tail of the pancreas and pass to the splenic lymph-nodes, at the hilus of the spleen. (2) Anteriorly lymphatics pass to "superior pancreatic lymph-nodes," superior gastric and hepatic nodes.
(4) Posteriorly lymphatics pass to the aortic, mesenteric, meso-colic, and inferior pancreatic nodes. The siDlenic, superior pancreatic, inferior pancreatic, and pancreatico-duodenal nodes are usually grouped together as " lymphoglandulse pancreatico-l'enales." Anastomoses exist between the lymphatics of the pancreas and those of the duodenum.
The lymphatics of the spleen (fig. 582) are found only in the form of a subcapsular plexus, there being no deep network (Mall). They pass to the splenic nodes [Igl. pancreatico-lienales], which are variable in number and are situated
The Lymphatics of the Excretory Organs and of the Suprarenal
The lymphatics of the kidney.— The lymphatic vessels from the deep capsular and parenchymatous lymphatics of the kidney run to the nodes of the lumbar cham (fig. 583). On the right side, part of the nodes concerned lie ventral and
part dorsal to the renal vein; one of the nodes lies as far caudalward as the bifurcation of the aorta; and one or two vessels may pass to pre-aortic nodes. On the left side the vessels end in four or five nodes of the lumbar group. The efferents of these nodes pass through the diaphragm and end in the thoracic duct.
The lymphatics of the Suprarenal. — The lymphatic vessels coming from the capsular and parenchymatous plexuses pass, on the right side, into two or three anterior para-aortic nodes, and a small retro-venous gland, near the pillar of the diaphragm; on the left side, into para-aortic nodes, and, in part, through the diaphragm, in company with the splanchnic nerve, to a posterior mediastinal
moses occur with the lymphatics of the kidney.
In addition to the capsular lymphatics proper, Kumita describes a subserous plexus, which is present over both kidney and adrenal, which anastomoses with the lymphatics of the liver and diaphragm. The efferents of this plexus collect, on the right side, to a gland placed to the right of the inferior vena cava, anterior to the right renal vein, and on the left side to a gland anterior to the left renal vein.
The lymphatics of the ureter. — Sakata has recently studied the lymphatics of the ureter. They fall into three groups: (1) An anterior (upper) group, which run to the anterior lumbar nodes, or join the renal lymphatics; (2) a middle group which pass to the posterior lumbar and interiliac nodes; (3) a posterior (lower) group which pass to hypogastric nodes and which anastomose with lymphatics of the bladder.
The lymphatics of the bladder. — The collecting vessels from the lower part of the ventral surface pass to a node of the external iliac group, situated near the femoral ring and the obturator nerve; those from the upper part of the ventral and dorsal surfaces pass to the middle node of the middle group of the external ihac chain, and from the rest of the dorsal surface they pass either to the hypogastric
nodes or beyond these to the nodes at the bifurcation of the aorta (fig. 584). In this latter group end also the vessels from the neck of the bladder. Along some of the lymphatics of the bladder are intercalated lymph-nodes, which have been termed anterior and lateral vesical nodes.
The lymphatics of the prostate. — The lymphatics of the prostate have been studied in the dog by Walker and in man by Bruhns. The collecting vessels, sbc to eight on each side, pass along the prostatic artery to the nodes along the external border of the hypogastric artery. These nodes are connected with those along the external and common iliac arteries, and it is possible, from an injection of the prostate, to fill the entire chain of nodes as far as the renal artery. A trunk from the posterior surface runs up over the bladder and curves outward to
the middle node of the middle group of the external iliac chain, and still other vessels from the posterior surface run first downward, pass around the rectum, and then ascend to the lateral sacral nodes. From the anterior surface a descending duct may follow the deep artery of the penis, and the internal pudic to the hypogastric
membrane of the glans follow the dorsal vein. Those from the penile and^membranous portions of the urethra start from the inferior surface and curve around the corpora cavernosa, as seen in fig. 586, to join the others along the dorsal vein. These vessels run with the vein to the symphj^sis, where the}' form a plexus in which there may be some small intercalated nodes. From this plexus vessels pass in two directions: — (1) Three or four vessels, the crural trunks, pass to the deep inguinal and external iliac nodes, and (2) one vessel enters the inguinal canal and ends in one of the external iliac nodes.
The vessels from the bulbar and membranous portions either follow the internal pudic arterj', or pass to the symphj-sis and end in the external iliac nodes, or pass onto the surface of the bladder and thence to the external iliac chain. The
The lymphatics of the scrotum form a rich plexus which has been pictured by Teichmann (fig. 547). The collecting vessels, ten to fifteen on either side, arise near the raphe and pass to the root of the penis, where some curve lateralward to the superior medial superficial inguinal nodes; while others, coming from the lateral surface of the scrotum, pass to the corresponding inferior nodes.
The lymphatics of the penis.— (1) The cutaneous lymphatics form a plexus from which collecting vessels follow the dorsal vein and end in the superficial mguinal nodes. (2) The lymphatics of the glans form an exceedingly rich plexus from which vessels follow the dorsal vein of the penis, as described under the urethra, and end in the deep inguinal and external iliac nodes. (3) The lymphatics of the erectile structures are little known.
The lymphatics of the testis are both superficial and deep, the latter being exceedmgly hard to inject. The collecting vessels follow the spermatic cord and artery and end in the lumbar nodes.
The lymphatics of the ductus deferens and vesiculse seminales. — In the ductus deferens only a superficial set has been injected, and its vessels passlto the external ihac nodes. The plexus of the vesiculaj seminales is double, superficial and deep, and its vessels pass to the external iliac and hypogastric nodes.
The lymphatics of the vulva.— Throughout the vulva there is an exceedingly rich, superficial lymphatic plexus, from which collecting vessels pass to the symphysis and there turn lateralward to the medial superficial inguinal' nodes. The fact that the capillary plexus is continuous from side to side and that there is a plexus of the vessels in front of the symphysis, makes the nodes of both sides liable to infection from a unilateral lesion.
The lymphatics of the clitoris. — The lymphatics of the glans of the clitoris form an abundant network from which collecting vessels pass toward the symphysis pubis, and thence principally to the deeper inguinal nodes, one or two, however, passing through the inguinal canal to terminate in the lower external iliac nodes.
The lymphatics of the ovary. — The ovary has a remarkably rich lymphatic plexus, from which from four to six vessels leave the hilus and follow the ovarian artery to the lumbar nodes. One vessel may run in the broad ligament to the internal iliac group.
The lymphatics of the uterus. — According to Poirier, the lymphatics of the uterus arise from three capillary plexuses, a mucous, a muscular, and a peritoneal. The collecting vessels from the body of the uterus are in three sets: — (1) Those from the fundus, consisting of four or five vessels, run lateralward in the suspen-
sory ligament of the ovary and follow the ovarian vessels to the lumbar and preaortic nodes. They anastomose with the lymphatics from the ovary opposite the fifth lumbar vertebra; (2) some small vessels from the fundus follow the round ligament of the uterus and terminate in the inguinal nodes; and (3) others from the body of the uterus pass laterally with the uterine vessels and terminate in the iliac nodes.
The collecting vessels from the cervix, five to eight in number, form a large lymphatic plexus just after leaving the cervix. From this plexus run three sets of vessels. Two or three vessels pass lateralward with the uterine artery in front of the ureter, and end in the external iliac nodes; a second set passes behind the ureter and ends in a node of the hypogastric group, and a third set from the posterior surface runs downward over the vagina and then backward and upward to end in the lateral sacral nodes and node of the promontory of the sacrum.
The lymphatics of the vagina (fig. 590) . — -There are two lymphatic plexuses in the vagina, a superficial and deep — the latter, the mucosal plexus, being exceedingly rich. The collecting vessels are in three groups. The superior set drains the upper third of the vagina and takes the same course as those from the lower cervical portion of the uterus; the middle set follows the vaginal artery to
the hypogastric nodes; and the inferior set runs to the lateral sacral nodes and to those of the promontory. The capillary network of the lower part of the vagina is continuous with the plexus of the vulva, which drains to the inguinal nodes.
1. THE LYMPHATIC NODES OF THE LOWER EXTREMITY
The principal group of nodes of the lower extremity is situated in the inguinal region, and hence is known as the inguinal group. It is in many respects similar to the axillary group, although it is not quite equivalent to it developmentally. The nodes composing it are divisible into a superficial and a deep group, the former containing many more and larger nodes than the latter. Furthermore, it is convenient to divide each of these groups into an upper and a lower set, the dividing line being an arbitrary line drawn horizontally through the point where the saphenous vein pierces the fascia of the fossa ovalis. The nodes above this line are termed collectively the inguinal nodes, while those below it are known as the subinguinal nodes.
The superficial inguinal nodes [Igl. inguinales superficiales] (fig. 591), lie along the base of the femoral trigone immediately below Poupart's ligament, superficial to the fascia lata. Then number varies from ten to twenty. They receive the subcutaneous drainage of the abdominal walls, the gluteal region, and the perineal region, and their efferents descend to the fossa ovalis, which they perforate along with the saphenous vein and terminate in the lower external iliac nodes.
The superficial subinguinal nodes [Igl. subinguinales superficiales], occupy the lower part of the femoral trigone and receive the entire superficial drainage of the leg, as well as a few vessels from the gluteal region and from the perineum. Thek efferents pierce the fossa ovalis and pass partly to the deep subinguinal nodes and partly directly to the lower external ihac nodes.
The deep nodes. — The deep nodes are small, and vary from one to three. They lie medial to the femoral vein, the highest one (node of Cloquet or of Rosenmiiller) being placed in the femoral ring and being of especial surgical
interest in that, when enlarged, it may simulate a strangulated hernia. The lowest node is below the point where the lesser saphenous joins the femoral vein. These deep nodes receive the deep lymphatics of the leg, the vessels from the glans penis in the male, and the clitoris in the female, and some of the vessels from the superficial subinguinal nodes. Their efferent vessels enter the external iliac nodes.
In addition to the inguinal group of nodes there are some other nodes in the lower limb situated along the course of the deep vessels. Thus there is a node in the course of the anterior tibial vessels below the knee, and there is a small
group of popliteal nodes [Igl. popliteae], in the popliteal space, which are in the course of the lesser saphenous vessels, and receive the vessels which accompany the posterior tibial and peroneal vessels and those which drain the knee-joint.
As in the upper extremity, the subcutaneous capillary plexus of the lower varies greatly in complexity, being most abundant in the soles of the feet. The collecting vessels form two main groups. The medial, larger group follows the saphenous vein, and ends in the superficial subinguinal nodes, while the lateral
group curves around to join the medial, partly in the leg and partly in the thigh. Two or three vessels from the heel follow the lesser saphenous vein to the popliteal space. The vessels from the upper and dorsal part of the thigh curve around on both sides to reach the superficial inguinal nodes. The vessels of the anus and
anterior tibial node, when it is present, and then passing backward to join the vessels which accompany the posterior tibial and peroneal arteries. These terminate in the popliteal nodes, from which efferents follow the com-se of the femoral artery and terminate in the deep inguinal nodes. The deep lymphatic vessels accompanying the gluteal and obturator arteries pass to the hypogastric nodes.
Lymphatics of the hip-joint. — According to Clermont, they accompany, in the main, the arteries about the joint. (1) Satellites of the anterior circumfle.x artery, draining almost the entire ventral surface, pass to the lateral inferior external iliac node. (2) Satellites of the posterior circumflex artery, draining the dorsal and medial surfaces, empty into the medial inferior external iliac node, occasionally into one of the deep inguinal nodes. (3) Satellites of the obturator vessel, draining the round ligament, empty into the obturator or hypogastric nodes. (4) Satellites of the inferior gluteal vessels, draining the dorsal surface, empty into three small nodes along the internal pudic and inferior gluteal arteries. Less important ("accessory") vessels are: satellites of the superior gluteal artery leading to a gluteal node; vessels from the dorsal surface which cross the lateral border of the pectineus to reach the medial inferior external iliac node; and vessels from the ventral surface, crossing parallel to the cotyloid notch, passing under the psoas to the lateral inferior external Uiae or one of the deep inguinal nodes.
Lymphatics of the knee-joint. — According to Tanasesco the lymphatics draining the structures around the knee-joint in the main follow the arteries about the joint and pass largely to the more deeply placed of the popliteal nodes. Some (superficial) follow the great saphenous vein to the subinguinal nodes, and sometimes deep vessels pass the pophteal nodes and, accompanying the femoral artery, run to the deep inguinal or inferior external iliac.
References for lymphatic system. — (Development) : Sabin, Amer. Jour. Anat., vols. 1, 3, 4, 9, also in Keibel and Mall's Human Embryology; Lewis, Amer. Join-. Anat., vols. 5, 9; Huntington and McClure, Amer. Jour. Anat., vol. 10; Clark, E. L., Anat. Record, vol. 6; Clark, E. R., Amer. Jour. Anat., vol.13. (Regeneration): Meyer, Johns Hopkins Hosp. Bui., vol. 17. (General): Bartels, in von Bardeleben's Handbuch d. Anatomic; Sappey, "Description et Iconographie des Vaisseaux Lymphatiques," Paris, 1885; Teichmann, "Das Saugadersystem," Leipzig, 1861. (Muscle, etc.): Aagaard, Anat. Hefte, Bd. 47. (Connective tissue): von Recklinghausen, "Die Lymphgefasse u. ihre Beziehung zum Bindegewebe," Berhn, 1862. (Stomata): Walter, Anat. Hefte, Bd. 46. (Lung): Miller, Anat. Rec, vol. 5. (Teeth): Schweitzer, Arch. f. mikr. Anat., Bd. 74. (Hoemolyinph glands): von Schumacher, Arch. f. mikr. Anat., Bd. 81. Tumors): Evans, Beitr.z. klin. Chir., Bd. 78.
PBOPESSOR OP ANATOMY, THE TDLANE UNIVERBITT OP LOUISIANA
THE nervous system of man, both anatomically and functionally, is the most highly developed and definitely distributed of all the systems of the body. It consists of an aggregation of peculiarly differentiated tissue-elements, so arranged that through them stimuli may be transmitted from and to all the other tissue systems or functional apparatuses. It is a mechanism with parts so adjusted that stimuli affecting one tissue may be conveyed, controlled, modified, and distributed to other tissues so that the appropriate reactions result. While protoplasm will react without nerves, while muscle will contract without the mediation of nerves, yet the nervous system is of the most vital importance to the higher organisms in that the stimuli required for the functioning of the organs are so distributed throughout their component elements that the necessary harmonious and coordinate activities are produced. For this purpose the nervous sj^stem permeates every organ of the body; nerve cell-bodies, accumulated into groups, receive impulses and give rise to the nerves which ramify and divide into smaller and smaller branches till the division attains the individual nerve-fibres of which the nerves are composed, and even the fibres bifurcate repeatedly before their final termination upon their allotted elements. So intimate and extensive is the distribution throughout that could all the other tissues of the body be dissolved away, still there would be left in gossamer its form and proportions — a phantom of the body composed entirely of nerves.
The parent portion or axis of the system extends along the dorsal mid-line of the body, surrounded by bone and, in addition, protected and supported by a series of especially constructed membranes or meninges, the outermost of which is the strongest. The cephalic end of the axis, the encephalon, is remarkably enlarged in man, and is enclosed within the largest portion of the bony cavity, the cranium, while the remainder of the central axis, the spinal cord, continues through the foramen magnum and lies in the vertebral canal.
The intimate connection of the axis with all the parts of the body is attained by means of forty-six pairs of nerves, which are attached to the axis at somewhat regular intervals along its extent. They course from their segments of attachment through the meninges and through their respective foramina in the bony cavity to the periphery. Of these craniospinal nerves, fifteen pairs pass through the cranium and are attached to the encephalon, and thirty-one pairs to the spinal cord. Some of the cranial nerves and all of the thirty-one pairs of spinal nerves contain both afferent fibres, which convey impulses from the peripheral tissues to the central axis, and efferent fibres, which convey impulses from the axis to the peripheral tissues. The different pans of nerves possess the two types of fibres in varying proportions.
Upon approaching the spinal cord, each spinal nerve is separated into two roots ■ — its posterior or dorsal root and its anterior or ventral root. The afferent fibres enter the axis by way of the dorsal roots, which are, therefore, the sensory roots, and the efl^erent fibres leave the axis by way of the ventral or motor roots.
THE NERVOUS SYSTEM
Fig. 594. — Showing the Ventral Aspect of the Central Nervous System, with the Proximal Portions of the Cranio-spinal Nerves attached and the Relation op the Proximal Portion (Gancliated Cord) of the Sympathetic Nervous System. The Encephalon or Brain is Straightened Dorsalward prom its more Horizontal Position with Reference to the Spinal Cord. The Spinal Ganglia and the Dorsal and Ventral roots of the Spinal Nerves may be noted.
All these parts are so intimately connected with each other that the division is purely arbitrary. The cranio-spinal nerves are anatomically continuous with the central system; their component fibres either arise within or terminate within the confines of the central system, and thus actually contribute to its bulk. The sympathetic system, however, may be more nearly considered as having a domain of its own. By communicating rami, it is intimately associated with the cranio-spinal nerves and thus with the central system, both receiving impulses from the central system and transmitting impulses which enter it. But, while its activities are largely under the control of the central system, it is possible that impulses may arise in the domain of the sympathetic system and, mediated by its nerves, produce reactions in the tissues it supplies without involving the central system at all. For this reason, as well as because of the structural peculiarities of the sympathetic system, the nervous system is sometimes divided into — (1) the cranio-spinal system, consisting of (a) the central system and (b) the cranio-spinal nerves; (2) the sympathetic nervous system, consisting of its various peripheral ganglia and their outgrowths forming its plexuses.
Within and closely pro.ximal to the central system or axis are grouped the parent cell-bodies whose processes comprise the nerve fibres of the cranio-spinal nerves. Other groups of nerve cell-bodies, distributed in the periphery without the bounds of the central system,, give rise to the fibres of the sympathetic nerves and plexuses. Any group of such cell-bodies situated in the periphery, whether belonging to the cranio-spinal or sympathetic system, is known as a ganglion.
THE DEVELOPMENT OF THE NERVOUS SYSTEM
The essential elements of the nervous system, the nerve cell-bodies and the essential portion of all nerve fibres, central, cranio-spinal and sympathetic, develop from one of the embryonic germ layers, the ectoderm, and all arise from a given region of that germ layer. Further a small portion of the supporting tissue of the nervous system, the neuroglia, is of the same origin.
In its development the nervous system is precocious. It is the first of the functional apparatuses to begin differentiation and is the first to acquire its form. The first trace of the embryo appears on the developing ovum as the embryonic area, and the rapidly proliferating cells of this area shortly become arranged into the three germinal layers: — the outer layer or ectoderm, the middle layer or mesoderm, and the inner layer or entoderm. Early in the process of this arrangement there is formed along the axial fine of the embryonic area a thickened plate of ectodermal cells, the neural plate. In the further proliferation of these cells, the margins of the neural plate, which he parallel with the long axis of the embryonic area, rise shghtly above the general surface, forming the neural folds, and the floor of the plate between the folds undergoes a slight invagination, the process resulting in the neural groove (fig. 595, A, A', B and B^). As development proceeds and the embryonic area assumes the form of a distinct embryo, the neural folds or lips of the groove graduaUy converge, and beginning at the oral end, finally unite. Thus the groove is converted into the neural tube, extending along the dorsal mid-hne and enclosed within the body of the embryo by the now continuous ectoderm above (fig 595, C^, D and D').
For a time the neural tube remains connected with the inner surface of the general ectoderm along the line of fusion by a residual lamina of ectodermal cells. This lamina is known as the ganglion crest (neural crest). It is a product of the proliferation of the ectoderm during the process of fusion, consists of the cells which composed the transition between the closing lips of the original groove and the general ectoderm or skin, and whose fusion aided in the closure of the tube. The ectoderm soon becomes separated from the ganghon crest and the cells of the crest become distinctly differentiated from the cells of the neural tube. The essential elements of the entire nervous system together with the neuroglia are derived from the cells of the neural tube and the cells of the ganglion crest.
Sections Illustrating the Development or the Neural Tube.
A, dorsal view of human embryo at beginning of infolding of neural plate to form neural groove. Amnion partly removed. (Graf Spee, from Keibel and Mall.) A', diagram of portion of a transverse section of an embryo as though taken through A at the fine a'. B, dorsal view of human embryo of 7 somites, neural tube not yet closed, Mall Collection. (Dandy, from Keibel and Mall.) B', diagram of portion of a transverse section of an embryo as though taken through B at the line b'. C'-, diagram of portion of a transverse section of an embryo as though taken through D at fine c'. D, dorsal view of human embryo of 8 somites, 2.11 m.m. long, neural tube closed except at caudal end. (KoUmann, from Keibel and Mall.) D', diagram of a portion of a transverse section of an embryo as though taken through D at^line d^
Before the caudal extremity of the tube is entirely closed, its oral end undergoes marked enlargement and becomes distended into three vesicular dilations, the anterior, middle, and posterior primary brain vesicles. The anterior of these primary vesicles give off a series of secondary vesicles and by these, followed by further dilations, flexures of its axis, and by means of locahzed thickenings of its walls, the portion of the tube included in the three primary vesicles develops into the encephalon or brain of the adult. The remainder of the tube becomes the spinal cord. This latter portion retains the simpler form. By the proliferation and migration laterally of the cells lining this portion of the tube, there results a comparatively even bilateral thickening of its walls so that the mature spinal cord retains a cylindrical form throughout its length.
The proliferating and migrating cells of the wall of the neural tube are known as germinal cells. The products of their division are apparently indifferent at first, but later they become differentiated into two varieties: (1) spongioblasts, or those cells which will develop into neuroglia, and (2) neiiroblasts, or those which will increase in size, develop processes and become nerve cell-bodies.' As described below, the processes given off by a neuroblast are of two general characters: (1) a long process or axone which goes to form nerves, nerve roots, and nerve fasciculi, and (2) dendritic processes which are numerous, branch much more frequently and extend but a short distance from the cell-body. An adult cell-body with all its processes is known as a neurone and the neuroblasts of the developing system become transformed into the neurones
Fig. 596. — Diagrams of Tkansvebse Sections or Embryonic Spinal Cords showing the Migration of the Cells op the Ganglion Crest to form the Spinal and Sympathetic Ganglia and the Origin of the Dorsal and Ventral Roots of the Spinal Nerves.
A, a- stage following D' of fig. 595. B, a later stage in which the ganglia and the components of the nerve are assuming their form resulting from the further migration and from processes being given off by the neuroblasts.
Sympatheti
of the varying sizes, shapes, and arrangements of processes characteristic of different divisions and localities of the nervous system. Usually the fii-st process to be noted is that which will become the axone or nerve fibre.
Neurones whose cell-bodies belong to the peripheral nervous system are not developed within the walls of the neural tube or central nervous system at all. These, comprising the spinal ganglion neurones and those of the sympathetic system, are derived from the cells of the ganglion crest. The wedge-shaped lamina of cells, comprising the ganghon crest, through rapid cell division, gradually extends outward and ventralward over the surface of the neural tube along either side. Soon the prohferation becomes most active in regions corresponding to the mesodermic somites or primitive body segments and this, together with the stress of the growing length of the body, results in the ganghon crest (originally a lamina) becoming segmented also. The segments or locahsed cell masses thus formed are the beginning not only of the spinal ganglia, but also of the ganglia of the entu-e sympathetic system. The cells of the crest migrate to assume a more lateral position, and then occurs a separation of their ranks. A portion of them remain in a dorsolateral position near the wall of the neural tube and develop into the neurones of the spinal ganglia (the sensory neurones of the spinal nerves), but others wander further out into the periphery and become the neurones of the sympathetic. Certain of those of this more nomadic group of cells settle within the vicinity of the vertebral column and by sending out their processes, form the gangliated cord or the proximal chain of sj^mpathetic ganglia; others migrate further, but in more broken rank, and become the gangha of the prevertebral plexuses (as the cardiac, coeliac and hypogastric plexuses), or the scattered intermediate chain of ganglia; while still others wander into the very walls of the peripheral organs and
occur singly or in groups in such plexuses as those of Auerbach and Meissner, within the tunics of the walls of the alimentary canal. Scattered along between these proximal, intermediate, and distal groups there are to be found small straggling gangha, many of which contain so few cell-bodies that they are indistinguishable with the unaided eye. All these sympathetic neurones, however, are always either directly or indirectly anatomically associated with and
bution of the spinal nerves.
The ganglia of the sensory portions of all those cranial nerves attached to the inferior of the main divisions of the brain and all the sympathetic ganglia of the head have an origin similar to that of the spinal and sympathetic gangha in the remainder of the body.
of the three vesicles give off secondary vesicles.
The walls of the posterior primary vesicle give rise to the posterior of the main divisions of the brain, the hind brain or rhombencephalon, the cerebellum developing from the anterior portion only of its dorsal wall, and the medulla oblongata and pons from its ventral wall. Its cavity persists and enlarges into the fourth ventricle of the adult, while the posterior portion of its dorsal wall does not develop functional nervous tissue at all but persists as a thin membrane known as the chorioid tela of the fourth ventricle. The cells which form the ganglia of the auditory and vestibular nerves arise from the dorsolateral regions of this vesicle.
From the middle primary vesicle comes the mid-brain or mesencephalon, the corprora quadrigemina [colliculi] developing from its entire dorsal wall and the cerebral peduncles occupying its ventral wall. The constriction between the middle and posterior vesicles becomes the isthmus of the rhombencephalon.
The anterior or first primary vesicle undergoes greater elaboration than either of the other two. At an early period it gives off a series of secondary vesicles or diverticula. First, two ventrolateral outpouchings occur, the optic vesicles, which later become the optic stalks and optic cups of the embryo. A medial protuberance becomes evident in its antero-dorsal wall and from each side of this quickly starts a lateral diverticulum. The two lateral diverticula thus arising from the protuberance are the beginning of the two cerebral hemispheres or the telencephalon, and the vesicular cavities contained persist as the two lateral ventricles of the brain. Soon, each of these vesicular rudiments of the hemispheres gives off ventrally from its anterior part a narrow tube-like diverticulum, each continuous into the parent primary vesicle. These are the olfactory vesicles which are transformed into the olfactory bulbs and olfactory tracts^ of the adult encephalon. (See fig. 598, B. and C.) As development proceeds, the cavities of the olfactory vesicles become occluded in man. However, in many of those animals
Fig. 601. — Diagram op Mesial Section op the Human Beain showing the Segments and THE Flexures and the Expansion of the Cebebral Hemispheres over the Other Portions op the Beain. The Thalamus is not shown.
in which the olfactory apparatus attains greater relative development than in man, these cavities persist as the olfactory ventricles. The cavities of the optic vesicles never persist as ventricles in the adult. They form stalks which represent the future courses of the optic nerves, while from their extremities are developed the retina;, portions of the ciliary bodies and portions of the iris of the ocular bulbs.
In addition to that which forms the cerebral hemispheres, the remaining portion of the anterior primary vesicle becomes the diencephalon or inter-brain. The lateral walls of this part thicken to form the tiialami, the posterior end of its dorsal wall gives off a secondary vesicle which becomes the pineal body or epiphysis, and from its ventral waU projects the infundibular recess which becomes the posterior lobe of the hypophysis with its infundibulum and tuber cinereum.
The adult human brain is characterised by the preponderant development of the cerebral hemispheres. The secondary vesicles forming these expand till, held within the cranial cavity, the hemispheres come to extend posteriorly completely over the thalamencephalon and the mesencephalon and even overlap the cerebellum to its posterior border. Their cavities, which persist from their origin from the anterior primary vesicle, are correspondingly large (the lateral ventricles) and comprise two of the four ventricles of the adult brain. The third ventricle becomes a narrow cavity situated between the two thalami. It represents the original cavity of the anterior primary vesicle from which the structures above mentioned arose as secondary vesicles. It remains continuous with the lateral ventricles by the two inter-ventricular foramina, known also as the /ora?«ma of mom'o, one into each cerebral hemisphere. The fourth ventricle of the adult represents the cavity of the posterior primary vesicle and comes to he between the cerebellum and medulla oblongata, since the cerebellum likewise extends posteriorly from its region of origin. The cavity of the middle primary vesicle becomes the cerebral aqueduct, or aqueduct of Sylvius, passing under the corpora quadrigemina and connecting the fourth or posterior ventricle with the third.
Development of the nerve fibres. — All axones begin as outgrowths or processes of the cytoplasm of neuroblasts. Most of such processes are sent out at a very early stage in the development of the nervous system and extend to the tissues they are to innervate when these tissues are as yet quite near the neural tube. Then, as the structures of the body elaborate and assume
their final forms and positions more remote from the central nervous system, the axones terminating in them must necessarily grow and be drawn out with the structures. At need, later axones are sent out by neurones developing later to supply the growth demands. Such axones follow the general paths made by those aheady extending to the tissues requiring them. Being processes of the cytoplasm of the cell-body, the growth and Ufe of all axones (and dendrites) is under the control of the nucleus in the cell-body. They grow by absorbing nourishment, or having added to them substances, from the tissue stroma through which they pass, which stroma may be either ectodermal or mesodermal in origin.
The great majority of axones in the central nervous sytem and all in the peripheral system have sheaths about them. The sheath is an acquired structure and is not added till a relatively late period of development. These sheaths are of two general varieties, sheaths con-
sisting merely of a fibrous coat with the nuclei belonging to it, and sheaths in which there has been added a coating of fat or myeUn, medullary sheaths. A nerve fibre consists of an axone and its sheath whether meduUated or non-medullated.
In the embryo, axones are given off from the developing neurones at a time when the entire ectodermic neural tube and embryonic ganglia and the mesodermic tissue surrounding them are each void of definite cell boundaries, each being a continuous mass of nucleated protoplasm, a syncyiium. From these syncytia are developed the fibrous connective tissues of the later framework supporting the nervous system. Of this, the fibrous tissue, neuroglia, is derived from the ectodermal syncytium, while the white and elastic fibrous tissues are derived from the mesodermal or mesenchymal syncytium. Before any connective tissue fibrils are developed in either syncytium, before and at the time of the ingrowth of blood-vessels into the developing gangha and the neural tube from the mesenchyme about them, there occurs an invasion of the mesenchymal syncytium into the ectodermal sjmcytium. This invasion occurs both as independent ingrowths and fusions at the periphery of the neural tube and by
the mesenchymal tissue being carried in by the ingrowing blood-vessels. After the mixture of the nuclei resulting from this fusion of the syncytia from the two sources, nuclei of mesodermal origin cannot be distinguished from those of ectodermal origin. Further, axones outgrowing from the embryonic ganglia and neural tube carry with them adhering portions of the ectodermal syncytium into the surrounding mesenchymal (fig. 603).
As development proceeds further, each syncytium becomes resolved into a reticulum of granular endoplasmic processes, containing the nuclei, with transparent exoplasm occupying its meshes. Fibrils soon form in the exoplasm and from these develop the connective-tissue fibres, whether neurogha in the central nervous system or mesenchymal fibrous tissue both without and within it. Certain of these fibrils of course surround the axones imbedded among them and from condensations of such fibrils are derived the fibrous sheaths of the axones, the sheath nuclei being acquhed from the adjacent nuclei of the original syncytium. These sheaths become more dense or pronounced as the axones extend and the fibrous tissue increases with growth, but there are always present fine marginal fibrils by which the sheaths grade into the looser fibrous tissue about them. It is generally beUeved that the tissue giving rise to these
THE Medullary Sheaths.
A, ventral portion of transverse section of an embryonic spinal cord involving portion of periphery of future ventral horn and part of the mesenchymal (mesodermal) syncytium outside the external limiting membrane of the cord. B, later stage of ventral root (peripheral) axone with myehn droplets adhering to it and fibrillated stroma surrounding it. C, stage in which myehn droplets, supported by fibrils of stroma, have increased and accumulated to form a practically continuous myehn or meduUary sheath. D, final stage with medullary sheath of even thickness, showing a node, and showing a neurilemma, sheath nucleus and fibrous framework of the myehn ("neurokeratin") derived from the fibrils of the original stroma.
syncytium
axone sheaths is of mesodermal origin. However, in amphibian larvae, Harrison has shown that some sheath nuclei at least are derived from the nuclei of the ectodermal syncytium of the ganghon crest, and Neal has noted in elasmobranchs the fact that nuclei migrate from the ventral waU of the neural tube along with the axones growing out to form the ventral roots of the spinal nerves. Whether aU or any of these nuclei are originally ectoderrnal, and, if so, whether such ectodermal tissue gives rise to all axone sheaths, especiaUy in the higher animals, are questionable contentions.
Axones possessing only fibrous sheaths comprise the non-meduUated nerve fibres. The majority of the sympathetic fibres are of this variety, and Ranson has found numerous nonmeduUated fibres present in the spinal nerves. The generally accepted form of non-medullated sympathetic fibres may be seen in fig. 609, C.
MeduUated fibres are those which possess an investing coat of fat or myehn in addition to the fibrous sheath. Most of the fibres in the central nervous system and most of those belonging to the cranio-spinal nerves proper acquire myehn sheaths. Myehn begins to appear upon axones shortly after the beginning development in the syncytium of the fibrils of the fibrous connective tissue, and thus after the beginnings of what will become the fibrous sheaths. The fibrous portions of the sheaths in the central nervous system develop less rapidly and are far more scant than those of the medullated fibres of the peripheral nerves. Probably because of this, it has been claimed that myehn begins to appear on the axones of the central system before the appearance of the fibrous sheath. In man, the first appearance of myelin occurs at about the fourth month, but myelinisation is not completed tiU after birth. The cranio-spinal nerves contain completely meduUated fibres before the central system does.
Myehn first appears as small droplets adhering to the axone at irregular intervals. These droplets increase in size and number and gradually accumulate to form a practicaUy continuous sheath of fat immediately investing the axone. They probably result from the coalescence of finer droplets floating in the surrounding fibrillated stroma. However, coUecting upon the axone,
the myelin retains the form of an emulsion, and as it increases in amount it incloses the adjacent fibrils which serve as a framework supporting the droplets of the emulsion in its meshes. Thus supported, the increasing myelin does not inclose the adjacent nuclei and endoplasm of the original syncytium. Probably because of the fibrous support of the myehn thus obtained, medullating fibres may be often seen presenting the beaded appearance shown in fig. 603, C, instead of an even distribution of the emulsion after it has become continuous along the axone. The "beads" probably represent the uneven beginning of the accumulation indicated in B of this figure. Increasing further, the myelin becomes a cyhnder of even thickness, the adjacent nuclei being pressed away against its surface and the adjacent fibrils also condensed upon it.
There is good reason to believe that the fibrous portion of the sheath, the primilive sheath or neurilemma, of the meduUated axone arises as a condensation of the fibrils of the surrounding stroma during development, that the sheath cells represent certain of the nearest nuclei incorporated from the original syncytium, and that the so-called neuro-keralin of the myehn represents the fibrous framework of the myehn inclosed by it during its accumulation upon the
Fig. 604. — Showing Some of the Varieties op the Cell-bodies op the Neurones OP the Human Nervous System, including the Dendrites and Small Portions op THE Axones. Axone Sheaths not included.
A. From spinal ganghon. B. From ventral horn of spinal cord. C. Pyramidal cell from cerebral cortex. D. Purkinje cell from cerebellar cortex. E. Golgi cell of type II from spinal cord. E. Fusiform cell from cerebral cortex. G. Sympathetic, a, axone; d, dendrites; c, collateral branches; ad, apical dendrites; hd, basal dendrites; c, central process; p, peripheral process.
axone. The theory that the myehn arises as a differentiated portion of the axone and the theory that it is formed by the neurilemma have been advanced. That it is accumulated from the immediately surrounding fluid of the stroma and adheres to the axone, added droplets coalescing there, in preference to other tissue elements because of some physical or chemical peculiarity of the axone, is more probably correct.
As the medullary sheath approaches completeness, constrictions may be observed at more or less regular intervals at which the myelin emulsion is absent. There are the nodes of Ranvier. The process by which they arise is not clearly understood. While the fibre is growing in length, new myehn is added at the nodes. The internodal segments of the sheath increase in length with age, and each segment may possess from one to several sheath nuclei.
In adolescence, fibres whose medullary sheaths are in various stages of completeness may be found both in nerve bundles in the central system and in the cranio-spinal nerves, and in both, the sheaths of some axones certainly never acquire mj'ehn. Also, in the adult, fibres whose medullary sheaths present the beaded appearance may be observed, probably representing cases of arrested accumulation of myelin. According to Westphal there is a slight increase in the thickness of the sheath with age. Larger axones acquire thicker sheaths of myeUn than smaller ones. Some fibres of the sympathetic system are meduhated but in such the myelin sheath is relatively thinner than in the cranio-spinal system. Beaded sheaths are frequent in sympathetic rami, though non-meduUated fibres are most abundant.
The nervous element is distinguished from all other units of the structure of organs in that its cell-body gives off outgrowths or processes of peculiarly great length and characteristic form. Knowledge of the possible lengths and complexity of these processes is comparatively recent and, to include them together with their parent cell-body, which has long been known as the 7ierue cell, the term neurone is used. The neurone, therefore, may be defined as the nerve cellbodj' with all its processes, however numerous and far reaching they may be. As a class of tissue elements, all neurones possess characteristics distinguishing them from other tissue elements, but the varieties within this class vary greatly. They vary in form both according to function and according to their locality in the nervous sj^stem. They vary in different animals, those in the higher animals being more complex in form. Fig. 604 gives illustrations of the external form of the cell-body of a few of the types found in the human nervous system.
(1) The dendritic processes or dendrites. These are the more numerous, the shorter, and the more frequently branching processes. They branch dichotomously and with rapid decrease in diameter as tliey branch. They serve to increase the absorbing surface of the cell-body for purposes of nutrition. Nerve impulses transmitted to the neurone are received by them and, therefore, they also serve to increase the recipient surface of the neurone. They never acquire meduUary sheaths. Since they convey impulses toward the cell-body, they are known as cellipital processes. Their absorbing and receptive surfaces are further increased by the presence of thickly placed, very minute projections known as "pin-head processes" or gemmules.
(2) The axone (neuraxis). Each neurone possesses properly but one of these processes. It arises from the cell-body more abruptly and quickly becomes smaller in diameter than are most dendrites before the latter decrease by branching. It is the longest process, in most cases very much longer than dendrites. Computation shows that some axones may contain nearly 200 times the volume of the parent cell-body of the neurone. Occasionally the axone gives off a few small branches near the cell-body. These are known as collaterals and are given off at practically right angles instead of dichotomously. Regardless of its branching, the axone maintains a practically uniform diameter throughout its long course. Its usual nervous function is to convey the impulses away from the cell-body, either to transmit them to other neurones by contact upon their dendrites, etc., or to appropriate elements of the other tissue systems of the body. Thus the axones are the cellifugal processes. There is one weU-known partial exception to this, namely, a part of the axone of the spinal ganglion type of neurone, the peripheral sensory neurone. The axone of this bifurcates a short distance from the cellbody into a peripheral and a central branch. See fig. 604, A, and fig. 610. The peripheral branch collects sensory impulses from the tissues of the body, the skin, etc., and, in conveying them to the central system, must necessarily convey them toward the cell-body as far as the point of bifurcation. Thence the impulse goes on in the central branch, stiU toward the central system but now, in conformity, away from the cell-body of the neurone. While the continued vitality of the axone is dependent upon the cell-body, in the peculiar case of the spinal ganglion neurone the impulse does not necessarily pass through the ceU-body. Experiments with the lower animals have shown that the impulses pass in the fibre from the peripheral tissues to the central system when the cell-bod^' has been cut away.
Terminations of axones. — At its final termination, well beyond its collateral branches and usually a considerable length from its ceU-body, the axone practically always divides into two or more terminal branches, and each of these breaks up, now dichotomously, into numerous terminal twigs. These terminal twigs are known as telodendria. Telodendria vary in number and characterof form according to the tissues in and upon which they terminate. Functionally, they are of three classes: Those terminating upon and in the other (peripheral) tissues of the body are either (1) sensory or (2) motor. In order to transmit impulses from one neurone to another, telodendria of the axone of one neurone are placed in contact with the dendrites or cell-body of another neurone forming (3) synapses. Upon approaching its termination, every axone loses its sheath, its telodendria being necessarily bare.
Sensory or afferent axones, receiving impulses from the skin or other epithelial surfaces, break up into very numerous telodendria each of which terminates directly upon the surface of the epitheUal cell, such as the cells of the germinative (Malpigin) layer of the skin or those of its basal or columnar layer. Such telodendria are known as free terminations. Free terminations are also to be found in the connective tissues of the body. A second varietj' of peripheral termination of afferent axones is the encapsulated for jn. These are known as 'end organs' and 'corpuscles' and are named according to their complexity and position. Three of the different forms of them are shown in fig. 605, B, C, and D. These are always situated in fibrous connective tissue from which their capsules are derived. Their most elaborate form is the lamellated or Pacinian corpuscle. Besides the motor axones terminating upon the fibres of voluntary or skeletal muscle, sensory impulses are carried from this tissue and one of the forms of telodendria for this purpose terminates upon the muscle fibre. This is known as
PERIPHERAL TERMINATIONS OF AXONES
Fig. 605.— Showing Some Varieties op Pekipheeal Terminations of Axones. 'Free termination' in epithelium (after Retzius). B. Krause's corpuscle from conjunctiva (after Dogiel). C. Meissner's corpuscle from skin (after Dogiel). D. Pacinian corpuscle (after Dogiel). E. Termination upon tendon sheath (Huber and DeWitt). F. Neuro- muscular spindle (after Ruffini). G. Motor termination upon smooth muscle-cell. H. Motor 'end-plate' on skeletal muscle fibre (after Bohmandvon Davidoff). a, axone; t, telodendria.
the 'neuromuscular spindle.' In it, the axone penetrates the sarcolemma and breaks into telodendria which coil spirally about the muscle fibre. The most extensive and elaborate form of sensory telodendria are those which spread out in plate-form upon tendons sheaths.
cortex, human, a, axone.
Motor peripheral axones terminate upon muscle and upon the secretory cell of glands (secretory axones). The motor cranio-spinal axones terminate upon skeletal (voluntary) muscle fibres and upon the cell-bodies of sympathetic neurones, the axones of which latter termmate upon cardiac muscle, smooth muscle fibres, and (secretory) in glands. Upon skeletal muscle, the terminal branch of the axone loses its sheath and breaks up into numerous telodendria which themselves branch and show very evident, irregular varicosities, the whole of which spread out
STRUCTURE OF THE NEURONE
in plate-form, and lie in contact with the substance of the muscle fibre. In man and all mammals, the area covered is usually somewhat oval and is marked by a granular differentiation of the muscle substance. This with the telodendria is known as a motor end-plate. The telodendria of sympathetic axones ending upon cardiac and smooth muscle fibres are fewer and simpler than those of cranio-spinal axones upon skeletal muscle. They consist of a few fine fibrils, with very small varicosities along them and at their ultimate terminations, which run longitudinally along the muscle fibre in close relation with its substance. Those upon gland cells are similar in character except that they often form a loose pericellular plexus about and upon the cell. The varicosities of telodendria are sometimes called end-feet and closer study of them has shown that they themselves consist of fine plexuses of the neuro-fibrils described below as contained in the cell-body of the neurone and extending throughout all its processes. Quite recently Boek has found that a sympathetic axone may sometimes accompany a cranio-spinal axone to an end plate on a skeletal muscle fibre.
^Synapses. — Every functionally complete nerve pathway consists of two or more neurones arranged in series. Very often, the series consists of many more than two, the impulses being transmitted from neurone to neurone. The axone, bearing the impulse away from the cell-body of one neurone, gives off terminal branches, each of which loses its sheath and breaks up into telodendria which twine themselves upon the dendrites or cell-body of another neurone. The mpulse is transferred from one neurone to another by means of contact rather than by direct anatomical continuity of the parts of the two neurones. Such terminations of axones are known as synapses.
In the terminal arrangement of the telodendria, synapses assume forms varying from compact "pericellular basketa" and "climbing fibres" to the more open arborisations composed of fewer twigs in simpler arrangements, "end-brushes." In case of the spinal ganghon type of neurone, the cell-body of the majority of which has no dendritic processes, the telodendria of the visiting axone form an anastomosing pericellular plexus inclosing the entire cell-body. This and the simple end-brush form of synapses are illustrated in fig. 606. It should be mentioned that, contrary to the general belief that impulses are transmitted by simple contact of the neurones in the series, it has been claimed that the ultimate twigs of the telodendria frequently penetrate the substance of the receiving cell-body and are fused in continuity. If during the processes of growth this becomes true, instead of being an appearance produced by the technique employed, it is better considered as merely an exception to the general rule.
Internal structure of the neurone. — The ceU-body of the neurone consists of a large, spherical, vesicular nucleus and a cytoplasm continuous into its axone and dendritic outgrowths. Its nucleus is further characterized by having most usually but one nucleolus, large, spherical and densely staining, situated in a karyoplasm containing otherwise a remarkably small amount of chromatin. Of the cytoplasm, the two most interesting structures are its fibrillar and its granular components.
The fibrillar structure, known as the neuro-fibrillce, represents a growth and elaboration of the spongioplasniic reticulum of the original, embryonal cell. The filaments increase in thickness during the development of the neurone, and, in the sending out of its processes, the meshes of the original reticulum become so drawn out in the processes as to give the appearance of a more or less parallel arrangement of threads. The reticular or net-like arrangement is usuallj- more nearly retained in the cytoplasm immediately about the nucleus, since here the stress of the outgrowing processes is less directly applied. In the cell-body of the spinal ganglion type of neurone, when no dendrites are given off, the net-like arrangement is apparent tlu-oughout the cytoplasm except in that region giving rise to the axone. On the other hand, in the typical so-called "pyramidal cell" of the cerebral cortex, from which two chief processes, the axone and the apical
often practically obliterated by the opposing growth stress.
So manifest does the parallel appearance of the neuro-fibrillfe in the processes often become that it has been interpreted as a series of individual and independent fibrils. In the application of gold chloride and similar methods to the neurones of lower forms, the reduced reagent is often precipitated upon the fibrils in parallel, seemingly independent lines. And, assuming the existence of independent fibrils, it has been contended that the neurone is not the functional unit of the nervous system but is itself composed of numerous functional units, individual fibrils, each for the conduction of nerve impulses. More recent and trustworthy methods, however, show that the neuro-fibrillaj retain their original reticular form, the threads anastomosing in all planes, and that the meshes of the net may, in the processes, be so drawn in one direction that a parallel appearance predominates. Further, it is now held that the neuroplasm, or the more fluid substance in which the fibrils lie throughout, is capable, and probably fully as capable, of conducting impulses as the fibrils.
Of the granules in the cytoplasm, the most interesting are those first described in detail by Nissl. These are the most abundant of those in the cell-body and are known as tigroid masses or Nissl bodies. They consist of numerous basophilic granules collected into clumps or masses of varying size. They are known to disappear during fatigue of the nervous system and they are more abundant in animals after a period of rest. They are distributed throughout the cytoplasm of the cell-body with the interesting exception that they are not found in the axone nor in the immediate vicinity of its place of origin from the cytoplasm, leaving a free region known as the axone hillock. As accumulated masses, they show characteristic shapes and arrangement
which are interpreted as signifying the shapes and arrangement of the spaces or meshes they occupy in the reticulum of the neuro-fibriUai. In cell-bodies of the varieties found in the ventral horns of the spinal cord or in the cerebral and cerebellar cortex, for example, the masses situated immediately about the nucleus are smaller, more numerous and of irregular shape. Nearer and in the beginnings of the dendrites, they are larger and mostly of fusiform or diamond shape. Farther out in the dendrites, they become more and more thin and attenuated; and in the distant reaches of the dendrites they are invisible or absent. In the cell-body of the spinal ganglion they are of irregular shape, smaller and more numerous throughout the cytoplasm, being slightly smaller and more thickly placed in the immediate vicinity of the nucleus. In all neurones several hours post-mortem, they appear in fewer and larger masses and it was in this condition that Nissl originally described them in man. Closely examined, the masses of all sizes are found to be accumulations of finer granules. Functionally they are supposed to be of nutritive significance, substances in unstable chemical equiblibrium, energy stored in the cytoplasm, capable at need of being split into simpler forms usable in the activities of the neurone. The fact that tigroid masses are absent from the axone hillock, the axone, and the distant reaches of the dendrites may signify that the substance is chiefly present here only in the spUt and usable form. Also, in the axone especially, the neurofibrilla? are so closely arranged that the meshes of their net here are too small to contain masses of appreciable size. Close examination of the axone hillock and longitudinal sections of the axone in deeply stained preparations usually show a few very minute basophilic granules.
Sheaths of the axone. — The great majority of axones acquire sheaths about them which isolate and protect them in their course through other tissues or in company with other axones. A nerve fibre is an axone together with its sheath. In transverse sections, the axone comprises
CONNECTIVE TISSUE OF NERVOUS SYSTEM
the central portion of the nerve fibre or its so-called "axis-cylinder." It is of course the essential portion of the fibre. As noted above in describing their development, nerve fibres are classified according to the character of the sheaths. Those which possess sheaths of myehn, a peculiar form of fat, are known as medullaled fibres, and those in which the sheaths are merely membranes of condensed fibrous tissue, void of myelin, are non-medullated fibres. A medullated fibre also possesses a fibrous membrane outside its myeUn sheath, known as the neurilemma or sheath of Schwann. The neurilemma is of the same origin and general structure as the sheath of the non-medullated fibre, and both possess nuclei scattered along thern. Medullated fibres, at more or less regular intervals, show constrictions at which the myelin sheath ceases, but over which the neurilemma continues. These constrictions are the 7iodes of Ranvier. The myelin is in the form of an emulsion, whose fat droplets are supported in a fine fibrous reticulum (neurokeratin), while the neurilemma without serves to hold it in place. The neurilemma possesses from one to three or four sheath nuclei between adjacent nodes of Ranvier.
Cephalic branch of spinal ganglion neurone
belonging to the sympathetic system (processes of sympathetic neurones) are non-medullated, but both partially medullated and completely medullated sympathetic fibres may be found. (See fig. 609.) The myehn sheaths of completely medullated sympathetic fibres are always thinner and less well developed than those of meduUated cranio-spinal fibres. Most of the fibres belonging to the cranio-spinal nerves and to the central nervous system are medullated, but among the fibres belonging to either there are to be found numerous non-medullated fibres. As indicated in fig. 609, nodes of Ranvier are absent in the medullated fibres of the central system.
In all the higher vertebrates, the myehn sheath always begins on the axone a short distance from its parent cell-body. The neurilemma of the medullated and the fibrous membrane of the non-medullated fibre are each faintly continuous with the fibrous connective tissue surrounding it, and, in the cranio-spinal and sympathetic ganglia, in which each cell-body of the neurone has a fibrous capsule about it, the fibrous membrane or the neurilemma, as the case may be, is directly continuous into the capsule of the ceU-body. Upon approaching its final termination, in other tissues or upon the dendrites or cell-body of other neurones, the nerve fibre always loses its sheath, the telodendria of the axone always being bare when placed in contact with the other element. In losing the sheath, the myelin sheath, if present, always ceases and the fibrous membrane becomes continuous with the tissue investing the receiving element, whether the capsule of the ganglion cell, the sarcolemma of the skeletal muscle fibre, the corium of the skin, or the connective-tissue capsule of the encapsulated terminal corpuscle,
The connective tissue of the nervous system is of two main varieties — while fibrous connective tissue and neuroglia. White fibrous tissue alone supports and binds together the peripheral system, and it is the chief supporting tissue of the central system. As connective tissues, these two varieties are quite similar in structure, each consisting of fine fibriUiE, either dispersed or in bundles, among which are distributed the nuclei of the parent syncytium. In both tissues nuclei are frequently found possessing varying amounts of cytoplasm which has not yet been transformed into the essential fibrils.
sent in from without, either as ingrowths of the developing pia mater, the most proximal of the membranes, or is carried in with the blood-vessels, of the walls of which it is an abundant component. Practically, the neuroglia as a connective tissue proper differs from white fibrous tissue only in origin and in its chemical or staining properties. Based upon the latter, there are methods of technique by which the two may be distinguished. White fibrous tissue is derived from the middle germ layer or the mesoderm, while neurogha comes from the ectoderm. The epithelium lining the central canal of the spinal cord and the ventricles of the encephalon, with which the canal is continuous, is the remains of the mother tissue of the neuroglia, and in the adult is the only vestige representing its origin. The cells of this epithelium are known as ependymal cells, and they are usually classed as a variety of neuroglia.
comprise all nerves in the periphery and all nerve tracts in the central system.
White substance [substantia alba] ("white matter") consists of a portion of nervous tissue in which medullated fibres predominate. The myelin sheaths, being in the form of a fat emulsion, reflect the entire spectrum and thus appear white.
Grey substance [substantia grisea] ("grey matter") is a portion of nervous tissue in which medullated axones do not predominate. Thus sympathetic ganglia and sympathetic nerves may be grey, though the term is usually applied to grey portions of the central system, such as the cerebral cortex, the central grey column of the spinal cord, etc. Such grey regions contain more cell-bodies of neurones than other regions, though at least half of their volume may consist of neuroglia, white fibrous connective tissue, blood-vessels, and axones of both varieties.
Neurone chains. — As noted above, the numerous neurones comprising the nervous system are functionally and anatomically related to aU the other tissues of the body and to each other. A functionally complete nerve pathway extends from the tissue in which the nerve impulse is aroused to the tissue in which a resultant reaction occurs. It is known that the simplest possible of such paths necessarily comprises at least two neurones. The great majority involve a greater number. The axone of one neurone bearing impulses from the peripheral tissue transfers the impulses to the dendrites or cell-body of another by synapsis, and the axone of this, in the same way, transfers them to another and so on till the final neurone receives the impulses and the telodendria of its axone transfer the impulse to the tissue element which reacts in response to the stimulus brought. Neurones are thus linked together in chains. A neurone chain may be defined, therefore, as a number of neurones associated with each other in series to form a functionally complete nerve pathway. Examples of the simplest forms of neurone chains as contained in the spinal cord are illustrated in fig. 610. An impulse aroused in the skin is borne by the spinal ganglion neurone to the spinal cord where, in the left half of the figure, telodendria of one of the terminal branches of its axone form synapses with a neurone in the ventral horn, and the axone of this bears the impulse out of the spinal cord to transmit it probably direct to skeletal muscle. This arrangement involves but two neurones and is supposed to be relatively rare. In the right half of the figure, a third neurone is seen interposed. This is a neurone, numerous in grey substance everywhere, whose axone is relatively short and branches frequently, making possible several synapses in the near neighbourhood of its parent cell-body. Its type is referred to as the Golgi neurone of type II. This interposed, gives a chain of three neurones between the origin of the impulse in the periphery and the contraction of muscle in response. Simple chains like these can result only in reflex activities and such chains are often called reflex arcs. Another chain is indicated in the figure in which the reflex action involves involuntary or smooth muscle. This must involve at least one sympathetic neurone, and, should the Golgi neurone of type II form synapses with the ventral horn neurone involved, a chain composed of four neurones results. In the more extensive and complex neurone chains, such as those in which the impulse from the skin, as above, ascends to the cerebral cortex and the resultant muscular contraction is thrown under cerebral control, each of the several neurones or links in the series is not only referred to by name according to the position of its cell-body, but each is often called according to its order in the series, as "neurone of first order," "second order," "third order," etc.
A given axone may break into a considerable number of branches each of which forms synapses with a different second neurone, or, if peripheral, the telodendria of each branch may terminate upon a separate peripheral tissue element. Thus, a given impulse aroused in a peripheral tissue element may be transmitted to an ever increasing number of neurones, and the initial neurone may comprise the first link in a number of neurone chains. Such is quite general in the structural plan of the nervous system throughout. It is thought possible to consider each neurone interposed in a chain as a separate source of energy, a sort of relay in the nerve path; that the impulse passing through the axone is gradually weakened in overcoming resistance, but, when transferred to another neurone, it incites a splitting into usable form of the substance represented by the tigroid masses and thus a liberation of energy or a reinforcement of the impulse. Further, thus is made possible the economy of one neurone serving as a hnk in a number of nem-one chains.
The axones (nerve fibres) taking part in the various neurone chains course in bundles of varying size, the larger of which have names. And there is a general tendency with axones of the same function and the same origin to course in company with each other. A fibre bearing impulses from the peripheral tissues to the central system is an afferent fibre or sensory fibre. A fibre bearing impulses out of the central system to peripheral tissues is an efferent fibre or motor
RELATIONS OF NEURONES
fibre. Efferent fibres which bear impulses to skeletal muscle are known as somatic ejferent fibres, while those which terminate upon the cell-bodies of sympathetic neurones and thus bear impulses destined for smooth muscle, cardiac muscle and glands (secretory) are visceral or splanchnic efferent fibres.
A nerve is a closely associated aggregation of parallel nerve fibres coursing in the periphery. It may be spinal, cranial or sympathetic according to its attachment or according to the origin of the majority of its fibres. It may contain several functional and structural varieties of fibres. The spinal nerves contain all structural varieties. Nerve roots are those bundles of fibres which join to form a nerve. Most of the cranial nerves have but one root of origin. Nerve roots, in their turn, are formed by the junction of smaller root-filaments. Nerve branches result from the division of the nerve, the separation of its component fibres into separate bundles. Some branches are of sufficient size and significance to be called nerves and given separate names. The smaller branches are called rami, twigs, etc.
OF Termination and Nuclei or Origin.
cent fasciculi com'sing parallel to each other comprise a funiculus, a bundle of bundles. The. central nervous system is bilaterally symmetrical throughout its length. A bundle of fibres arising from cell-bodies situated on one side and crossing the mid-line transversely to terminate in the opposite side is a commissure. The commissures vary greatly in size and contain fibres crossing in both directions. Scattered fibres which cross the mid-line are commissural fibres. Fibres of varying lengtli, arising from cell-bodies situated in one locality of the central sj-stem, which do not cross the mid-Une, but terminate in other localities of the same side, above and below the level of their origin or in a different region of the same level, form association fasciculi. The shortest association fasciculi, not extending bejj^ond the bounds of a given division of the central sj-stem, are known as fasciculi proprii. When bundles of the same origin, functional direction and significance, running one on either side of the mid-line, cross the mid-line they are said to decussate and the crossing is known as a decussation. In the decussations, the direction of the crossing is oblique rather than transverse.
The cell-bodies of neurones whose axones go to form certain nerve roots, fasciculi and certain commissures show a tendency to accumulation in localized masses. In the peripheral system, such an accumulation of cell-bodies is known as a ganglion; in the central system such is distinguished as a nucleus. Thus, there are the sympathetic ganglia which give rise to sympathetic nerves and sympathetic roots of nerves; and on the beginning of each spinal nerve there is a spinal ganglion which gives rise to the afferent fibres of its dorsal root and in its nerve trunk. There are ganglia on the cranial nerves which give rise to the afferent or sensory axones in them and which are of the same significance as the spinal ganglia. Every ganglion, therefore, has
connected with it bundles of nerve fibres. Some of these fibres bear impulses from neighboring ganglia or from the tissues of the neighboring organs and transmit them to the cell-bodies of the ganglion ; others arise from the cell-bodies in the ganglion and bear impulses to the central system or, in case of the sympathetic, to other ganglia or to the tissues of the peripheral organs. Necessarily, the larger the ganglion, the larger will be the bundles of fibres connected with it.
A nucleus of termination is an accumulation of cell-bodies in which the axones of a given fasciculus or of a nerve root terminate, that is, ceU-bodies which, by synapses, receive the impulses borne by the terminating axones. In most cases the impulses transferred to a nucleus so named are sensory in character. The nucleus may be considered as a defined region in which neurones of the next order are interpolated in a given nerve pathway or system of neurone chains. Fasciculi in the spinal cord which bear impulses to the cerebrum have their nuclei of termination in the meduUa oblongata, and the sensory or afferent axones of the cranial nerves find their nuclei of termination upon entering the central system.
A nucleus of origin is an accumulation of ceU-bodies of neurones which give origin to the axones going to form a given nerve root or a fasciculus. Strictly speaking, a nucleus of termination for one nerve tract is the nucleus of origin for another, the next link in the neurone chain. However, the term is commonly used to distinguish a group of cell-bodies giving rise to a motor nerve tract. Thus each motor cranial nerve has its nucleus of origin within the central system. The central grey substance of the spinal cord is in the form of a column continuous throughout the length of the cord and so the cell-bodies in the ventral horns of this column which give rise to the motor or afferent roots of the spinal nerves are not considered as grouped into nuclei of origin, one for each of the motor roots.
The dorsal root of each spinal nerve is afferent or sensory in function and its axones arise as processes of cell-bodies comprising the spinal ganglion of the nerve. The afferent or sensory fibres of the cranial nerves arise as processes of ceU-bodies comprising the gangha of the cranial nerves, which ganglia are, in development and character, exactly homologous to the spinal ganglia.
The ventral root of each spinal nerve is efferent or motor in function and its fibres arise as processes of cell-bodies situated in the ventral horn of the grey substance of the spinal cord. The efferent or motor fibres of the'cranial nerves arise as processes of ceU-bodies accumulated as nuclei of origin in the grey substance of the encephalon, and homologous with those cell-bodies of the ventral horns of the spinal cord which give origin to the ventral-root fibres.
The general relation of the cerebrum (which includes the mesencephalon) to the remainder of the nevous system is a crossed relation. Neurone chains from the general body to the cerebrum, via the spinal nerves and cord and via the cranial nerves and medulla oblongata and pons of one side, cross the mid-line to terminate in the opposite side of the cerebrum. Axones, and neurone chains, arising in response in one side of the cerebrum, likewise usually decussate in descending to terminate in the respective regions of the opposite side.
Many of the names given nervous structures, prior to 1850 especially, instead of suggesting something of their functional or anatomical significance, indicate nothing more than active imaginations for accidental resemblances between the various structures of the nervous system and objects in ordinary domestic environment. Also, quite often the name given a structure is merely the name of some anatomist associated with it. The much needed elimination of these old non-descriptive names is proving a very slow process. Attempts have often increased the difficulty by making necessary the use of several names for a given structure instead of one. The most recent and concerted attempt, the nomenclature known as the BNA (anatomical names chosen by a commission appointed for the purpose which convened in Basle in 189.5), has been adopted by modern text-books. It is here used in the form of the English equivalents of the Latin terms, except in cases of those Latin terms which have become so commonly used as to be considered words incorporated into the English language. The BNA has retained manj' of the old names and, since a name should indicate something of the locality and significance of the structure to which it is applied, it is not yet wholly satisfactory throughout. In applying the names of a few fasciculi, the BNA in the following pages is slightly modified by so compounding the name that the first word in the compound indicates the locality of origin of the fasciculus and the second, the locahty of its termination. Thus, "Dorsal spino-cerebellar fasciculus" indicates the more dorsally coursing of the fasciculi which arise from cell-bodies in the spinal cord and terminate in the cerebellum. This principle appUes to many of the BNA names without change, as "lateral cerebrospinal fasciculus."
The central nervous system [systema nervorum centrale] or organ is an aggregation of nuclei, fasciculi and commissures — a large axis of grey and white substance situated in the dorsal mid-line of the body — and the bundles of fibres connecting it with the tissues of other systems and with the peripheral ganglia are of necessity correspondingly large. So numerous are the axones connecting it and so intimately are its neurones associated that a disturbance affecting any one part of the system may extend to influence all other parts. The enlarged cephalic extremity of this central axis, the brain or encephalon, is a special aggregation of nuclei and masses of grey substance, many of which are much larger than any found in the periphery.
MORPHOLOGY OF SPINAL CORD 771
In the study of the central nervous system its enveloping membranes or meninges are met with first, and logically should be considered first, but since a comprehensive description of these membranes involves a foreknowledge of the various structures with which they are related, it is more expedient to consider them after making a closer study of the entire system they envelop.
For convenience of study, the central nervous system is separated into the gross divisions, spinal cord and brain (encephalon) as illustrated in fig. 602. Each of these divisions will be subdivided and considered with especial reference to its anatomical and functional relations to the other divisions and the interrelations of its component parts.
I. THE SPINAL CORD
The spinal cord [medulla spinalis] is the lower (caudal) and most attenuated portion of the central nervous system. It is approximately cylindrical in form and terminates conically. Its average length in the adult is 45 cm. (18 in.) in the male and 42 cm. in the female. It weighs from 26 to 28 grams or about 2 per cent, of the entire cerebro-spinal axis.
gravity is given as 1.038.
The Line of division between the spinal cord and the medulla oblongata is arbitrary. The outer border of the foramen magnum is commonly given, or, better, a transverse line just below the decussation of the pyramids. Lying in the vertebral canal, the adult cord usually extends to the upper border of the body of the second lumbar vertebra. However, cases may be found among taller individuals in which it extends^'no farther than the last thoracic vertebra. With increase in stature, its actual length increases, but the extent to which it may descend the vertebral canal decreases. Up to the third month of intra-uterine life it occupies the entire length of the vertebral canal, but owing to the fact that the vertebral column lengthens more rapidly and for a longer period than does the spinal cord, the latter, being attached to the brain above, soon ceases to occupy the entire canal. At birth its average extent is to the body of the third lumbar vertebra.
In position in the body, the spinal cord conforms to the curvatures of the canal in which it lies. In addition to the bony wall of the vertebral canal, it is enveloped and protected by its three membranes or meninges, which are continuous with the like membranes of the encephalon: first, the pia mater, which closely invests the cord and sends ingrowths into its substance, contributing to its support; second, the arachnoid, a, loosely constructed, thin membrane, separated from the pia mater by a considerable subarachnoid space ; thnd, the dura niater, the outermost and thickest of the membranes, separated from the arachnoid by merely a sHt-hke space, the subdural space.
The intimate association of the central system with all the peripheral organs is attained chiefly through the spinal cord, and this is accomplished by means of thirty-one pairs of spinal nerves, which are attached along its lateral aspects. The nerves of each pair are attached opposite each other at more or less equal intervals along its entire length, and in passing to the periphery they penetrate the meninges, which contribute to and are continuous with the connective-tissue sheaths investing them. Each nerve is attached by two roots, an afferent or dorsal root, which enters the cord along its postero-lateral sulcus, and an efferent or ventral root, which makes its exit along the ventro-lateral aspect.
With its inequahties in thickness and its conical termination the spinal cord is subdivided into four parts or regions: — (1) The cervical portion, with eight pairs of cervical nerves; (2) the thoracic portion, with twelve pairs of thoracic nerves; (3) the lumbar portion, with five pairs of lumbar nerves; and (4) the conus meduUaris, or sacral portion, with five pairs of sacral and one pair of coccygeal nerves. From the termination of the conus meduUaris, the pia mater continues below in the subarachnoid space into the portion of the vertebral canal not occupied by the spinal cord, and forms the non-nervous, slender, thread-like terminus, the filu7n terminale. This becomes continuous with the dura mater at its lower extremity.
In the early fetus the spinal nerves pass from their attachment to the spinal cord outward through the intervertebral foramina at right angles to the long axis of the cord, but, owing to the fact that the vertebral column increases considerably in length after the spinal cord has practically ceased growing, the nerve-roots become drawn caudad from their points of attachment, and, as is necessarily the case, their respective foramina are displaced progressively downward as the termination of the cord is approached, until finally the roots of the lumbar and sacral nerves extend downward as a brush of parallel bundles considerably below the levels at which they are attached. This brush of nerve-roots is the Cauda equina. The dura mater, being more closely related to the bony wall of the canal than to the spinal cord, extends with the vertebral column and thus envelops the Cauda equina, undergoing a slightly bulbous, conical dilation which decreases rapidly and terminates in the attenuated canal of the coccyx as the coccygeal ligament.
The enlargements. — Wherever there is a greater mass of tissue to be innervated, the region of the nervous system supplying such must of necessity possess a greater number of neurones. Therefore, the regions of the spinal cord associated with the skin and musculature of the regions of the superior and
Thoracic region
inferior limbs are thicker than the regions from which the neck or trunk alone are innervated. Thus in the lower cervical region the spinal cord becomes broadened into the cervical enlargement, and likewise in the lumbar region occurs the Imnbar enlargement. The spinal nerves attached to these regions are of greater size than in other regions.
The cervical enlargement [intumescentia cervicalis] begins with the third cervical vertebra, acquires its greatest breadth (12 to 14 mm.) opposite the lower part of the fifth cervical vertebra (origin of the sixth cervical nerves), and extends to opposite the second thoracic vertebra. Unlike the lumbar enlargement, its lateral is noticeably greater than its dorso-ventral diameter.
The lumbar enlargement [intumescentia lumbalis] begins gradually with the ninth or tenth thoracic vertebra, is most marked at the twelfth thoracic vertebra (origin of the fourth lumbar nerves), and rapidly diminishes into the conus medullaris.
Both the lumbar and thoracic regions are practically circular in transverse section. Neither diameter of the lumbar is ever so great as the lateral diameter of the cervical enlargement. The thoracic part attains its smallest diameter opposite the fifth and si.xth thoracic vertebrae (attachment of the seventh and eighth thoracic nerves.)
The enlargements occur with the development of the upper and lower limbs. In the embyro they are not evident until the limbs are formed. In the orang-utan and gorilla the cervical enlargement is greatly developed; the ostrich and emu have practically none at all.
Surface of the spinal cord. — The cord is separated into nearly symmetrical right and left halves by the broad anterior median fissure into which the pia mater is duplicated, and opposite this, on the dorsal surface, by the posterior median sulcus. Along the lower two-thirds of the cord this sulcus is shallowed to little
SURFACE OF SPINAL CORD
more than a line which marks the position of the posterior median septum; in the medulla oblongata it opens up and attains the character of a fissure. Each of the two lateral halves of the cord is marked off into a posterior, lateral, and anterior division by two other longitudinal sulci. Of these, the postero-lateral sulcus occurs as a shght groove 2 to 3| mm. lateral from the posterior median sulcus, and is the groove in which the root filaments of the dorsal roots enter the cord in regular linear series. The ventral division is separated from the lateral
by the antero -lateral sulcus. This is rather an irregular, linear area than a sulcus. It is from 1 to 2 mm. broad, and represents the area along which the efferent fibres make their exit from the cord to be assembled into the respective ventral roots. This area varies in width according to the size of the nerve-roots, and, like the postero-lateral sulcus, its distance from the mid-line varies according to locality, being greatest on the enlargements of the cord. In the cervical region, and along a part of the thoracic, the posterior division is subdivided by a delicate longitudinal groove, the postero-intermediate sulcus, which becomes more evident
towardjthe medulla oblongata and represents the line of demarcation between the fasciculus gracihs and the fasciculus cuneatus. Occasionally in the upper cervical region a similar line may be seen along the ventral aspect close to the anterior
Collectively, the entire space between the posterior median sulcus and the line of attachment of the dorsal roots is occupied by the posterior funiculus; the lateral space between the line of attachment of the dorsal and that of the ventral
roots, by the lateral funiculus; and the space between the ventral roots and the anterior median fissure, by the anterior funiculus. Each of these funiculi is subdivided within into its component fasciculi.
The dorsal and ventral nerve-roots are not attached to the cord as such, but are first frayed out into numerous thread-like bundles of axones which are distributed along their lines of entrance and exit. These bundles are the root filaments [fila radicularia] of the respective roots. The fila of the larger spinal nerves are fanned out to the extent of forming almost continuous lines of attachment, while in the thoracic nerves there are appreciable intervals between those of adjacent roots. Throughout, the intervals are less between the fila of the ventral than between those of the dorsal roots.
Internal Structure of the Spinal Cord
By reflected light masses of medullated axones appear white in the fresh, and such masses are known as white substance. The spinaal cord consists of a continuous, centrally placed column of grey substance surrounded by a variously thickened tunic of white substance. The closely investing pia mater sends
numerous ingrowths into the cord, bearing blood-vessels and contributing to its internal supporting tissue. The volume of white and of grey substance varies both absolutely and relatively at different levels of the cord. The absolute amount of grey substance increases with the enlargements. The absolute amount of white substance also increases with the enlargements coincident with the greater amount of grey substance in those regions. The relative amount of white substance increases in passing from the conus medullaris to the medulla oblongata, due to the fact that the ascending and descending axones associating the cord with the encephalon are the one contributed to the cord and the other gradually terminating in it at different levels along its entire descent.
The grey substance. — In the embryo all the nerve-cells of the grey substance are derived from the cells lining the neural tube, and in the adult the column of grey substance, though greatly modified in shape, still retains its position about the central canal. In transverse section the column appears as a grey figure of two laterally developed halves, connected across the mid-line by a more attenuated portion, the whole roughly resembling the letter H. The cross-bar of the H is known as the grey commissure. Naturally, it contains the central canal, which is quite small and is either rounded or laterally or ventrally oval in section, according to the level of the cord in which it is examined. The canal continues upward, and in the medulla oblongata opens out into the fourth ventricle. Downward, in the extremity of the conus medullaris, it widens slightly and forms the rhomboidal sinus or terminal ventricle, then is suddenly constricted into an extremely small
canal extending a short distance into the filum terminale, and there ends blindly. The grey commissure always lies somewhat nearer the ventral than the dorsal surface of the cord, and itself contains a few medullated axones which vary in amount in the different regions of the cord. The medullated axones crossing the mid-line on the ventral side of the central canal form the ventral or anterior white commissure ; those, usually much fewer in number, crossing on the dorsal side of the central canal, form the dorsal or posterior white commissure. These two commissures comprise fibres crossing in the grey substance as distinguished from others which cross in the white substance dorsal and ventral to them. The axones of these commissures serve in functionally associating the two lateral halves of the grey, column.
Each lateral half of the grey column presents a somewhat crescentic or commashaped appearance in transverse section, which also varies at the different levels of the cord. At all levels each half presents two vertical, well-defined horns, themselves spoken of as columns of grey substance. The dorsal horn [columna posterior] extends posteriorly and somewhat laterally toward the surface of the cord along the line of the postero-lateral sulcus. It is composed of an apex and a neck [cervix columnse posterioris].
In structure the apex is peculiar. The greater portion of it consists of a mass of small nerve-cells and neurogha tissue, among which a gelatinous substance of questionable origin predominates, giving the horn a semi-translucent appearance. This is termed the gelatinous substance of Rolando, to distinguish it from a similar appearance immediate^ about the central canal, the central gelatinous substance. The apex of the dorsal horn is widest in the regions of the enlargements, especially the lumbar, and the gelatinous substance of Rolando is most marked in the cervical region. In these regions the cervix consists of a slight constriction of the dorsal horn between the apex and the line of the grey commissure. In the thoracic region, however, the base of the cervix is the thiclcest part of the dorsal horn. This thickness is due to the presence there of the nucleus dorsalis, or Clarke's column — a column of grey substance containing numerous nerve-cells of larger size than elsewhere in the dorsal horn, and extending between the seventh cervical and third lumbar segments of the cord. Tapering finelj' at its ends, this nucleus attains its height in the lower thoracic or first lumbar segment. About the ventro-lateral periphery of the nucleus dorsalis are scattered nerve-cells of the same type as contained in it. These cells ai'e sometimes distinguished as Stilling's nucleus, though Clarke's column was also described by Stilling. They are more numerous about the lower extremity of the nucleus dorsalis, and they continue to appear below its termination in the lumbar region.
The ventral horn [columna anterior] of each lateral half of the grey figure is directed ventrally toward the surface of the spinal cord, pointing toward the antero-lateral sulcus. It contains the cell-bodies which give origin to the efferent or ventral root axones, and these axones make their emergence from the spinal cord along the antero-lateral sulcus. The ventral horns vary markedly in shape in the different regions. In certain segments each ventral horn is thickened laterally and thus presents its two component columns of grey substance : the lateral horn [columna laterahs], a triangular projection of grey substance into the surrounding white substance, in line with or a little ventral to the line of the grey commissure; and the ventral horn proper [columna anterior], projecting ventrally. In the mid-thoracic region the lateral horn is relatively insignificant, and the anterior horn is quite slender; in the cervical and lumbar enlargements both horns are considerably enlarged.
The grey substance is not sharply demarcated from the white. In the blending of the two there are often small fasciculi of white substance embedded in the grey, and likewise the grey substance sends fine processes among the axones composing the white substance. Such processes or grey trabeculse are most marked along the lateral aspects of the grey figure and present there the appearance known as the reticular formation. The reticular formation of the spinal cord is most evident in the cervical region (fig. 616).
Minute structure. — The large cell-bodies of the ventral horn as a whole are divisible into four groups, only three of which are to be distinguished in the mid-thoracic region of the spinal cord: — (1) A ventral group of cells, sometimes separated into a ventro-lateral and a ventromedial portion (see figs. 616, 619), occupies the ventral horn proper, is constant throughout the entire length of the cord, and contributes axones to the ventral root, most of which probably supply the muscles adjacent to the vertebral column; (2) a dorso-medial group of cells, situated in the medial part of the ventral horn, just below the level of the central canal, gives origin to axones some of which go to the ventral root of the same side, but most of which cross the midline vi& the anterior white commissure, either to pass out in the ventral root of the opposite side or to enter the white substance of that side and course upward or downward, associating with other levels of the cord. Some of its axones terminate among the cells of the ventral horn
in the same level of the opposite side; (3) a lalEral group of cells, sometimes separated into a dorsolateral and a ventro-lateral portion, occupies the lateral column or horn, and is best differentiated in the cervical and lumbar enlargements. Most of the axones arising from its larger cells are contributed to the ventral root of the same side, and such axones probably supply the muscles of the extremities. Some of those from its ventral portion are distributed to the muscles of the body-wall; the dorso-lateral portion is that part of the lateral column \vhich persists throughout the cord, and is considered as supplying the visceral efferent fibres in the ventral roots. (4) an intermediate group, occupying the mid-dorsal portion of the ventral horn. Axones arising from its cells are probably seldom contributed to the ventral root, but instead course wholly within the central nervous system. Some pass to the opposite side of the cord, chiefly via the anterior and possibly the posterior white commissure, to terminate either in the same or different levels of the grey column. Others of longer course pass to the periphery of the cord, join one of the spino-cerebellar fasoicuh, and pass upward to the cerebellum.
Furthermore, there are scattered throughout the grey substance many smaller cell-bodies of neurones. These give rise to axones of shorter course, either commissural or associational proper. Of such axones many are quite short, coursing practically in the same level as that in which their cells of origin are located, and serve to associate the different parts of the grey substance of that level. Others course varying distances upward and downward for the association of different levels of the grey column.
It is evident from the above that in addition to the various nerve-ceUs it contains, there is also to be found a felt-work of axones in the grey substance. Many of these axones are meduUated, though not in sufficient abundance to destroy the grey character of the substance. The felt-work is composed of three general varieties of fibres: — (1) The terminal branches of axones entering from the fasciculi of the white substance and forming end-brushes about the various cell-bodies in the grey substance (partly meduUated) ; (2) axones given off from the cells of the grey substance and which pass into the surrounding white substance either to enter the ventral-roots or to join the ascending and descending fasciculi within the spinal cord (partly meduUated); (3) axones of Golgi neurones of type 11, which do not pass outside the confines of the grey substance (non-meduUated). Some axones of any of these varieties may cross the mid-line and thus become commissural. In general all fibres of long course acquire medullary sheaths a short distance from then- cells of origin, and lose them again just before termination.
The white substance of the spinal cord. — The great mass of the axones of the spinal cord course longitudinally and form the thick mantle surrounding the column of grey substance. This mantle is divided into right and left homolateral halves by the anterior median fissure along its ventral aspect, and along its dorsal aspect by the posterior median septum, which is for the most part a connective-tissue partition derived from the pia mater along the line of the posterior median sulcus. The mantle is supported internally by interwoven neuroglia and white fibrous connective tissue, the latter, derived chiefly from the pia mater, closely investing it without.
The axones of the white substance belong to three general neurone systems: — (1) The spino-cerebral and cerebrospinal system, which consists of axones of long course, one set ascending and another descending, forming links in the neurone chains between the cerebrum and the peripheral organs. The ascending axones of this system collect the general bodily sensations which are conve.yed to the cerebrum, the cells of which in response contribute axones which descend the cord, conveying efferent or motor impulses. (2) The spino-cerebellar and cerebellospinal system consists of conduction paths, one set ascending and another descending, which are connections between cerebellar structures and the grey substance of the spinal cord. (3) The spinal association and commissural system of axones which serve to associate the different levels and the two sides of the spinal cord and which are proper to the spinal cord, i. e., they do not pass outside its confines.
Both the first and second systems increase in bulk as the cord is ascended. The ascending axones of each system are contributed to the white substance of the cord along its length, and therefore accumulate upward; the axones descending from the encephalon are distributed to the different levels of the cord along its length, and therefore diminish downward.
The mass of the third system of axones varies according to locality. Wherever there is a greater mass of neurones to be associated, as there is in the enlargements of the cord, a greater number of these axones is required. Their cells of origin, being in the grey substance of the cord, contribute to its bulk and thus both the cells and the axones of this S3^stem serve to make the enlargements more marked. In the lumbar and sacral regions the greater mass of the entire white substance consists of axones belonging to this system. It forms a dense felt-work about the grey column throughout the cord. Necessarily this system contains axones of various lengths. Some merely associate different levels within a single segment
CONDUCTION PATHS
of the cord; others associate the different segments with each other. Axones which associate the structures of the spinal cord with those of the medulla ■ oblongata may be included in this system. Many of these axones cross the midline both in the grey and in the white substance to associate the neurones of the two sides of the grey column. For purposes of distinction, such as cross the midline are called commissural fibres, while those which course upward and down-
(1) Physiological investigation. — (a) Direct stimulation of definite bundles or areas in section and carefully noting the resulting reactions which indicate the function and course of the axones stimulated, (b) 'WaUerian degeneration' and the application of such methods as that of Marchi. When an axone is severed, that portion of it which is separated from its parent cell-body degenerates. Likewise a bundle of axones severed from their cells of origin, whether by accident or design, will degenerate from the point of the lesion on to the locality of their termination in whichever direction thisimay be. This phenomenon was noted by Waller in 1852 and is known as WaUerian degeneration. By the application of a staining technique which is differential for degenerated or degenerating axones and a study of serial sections containing the axones in question, their course and distribution may be determined. The locality of their cells of origin, if unknown, may be determined by repeated experiment till a point of lesion is found not followed by degeneration of the axones under investigation, (c) The axonic reaction or 'reaction from a distance.' Cell-bodies whose axones have been severed undergo chemical change and stain differently from those whose axones are intact. Thus cell-bodies giving origin to a bundle of severed axones may be located in correctly stained sections of the region containing them.
(2) Embryological evidence. — In the first stages of their development axones of the cerebro-spinal nervous system are non-medullated. They acquire their sheaths of myelin later. Axone pathways forming different chains become medullated at different periods. Based upon this fact a method of investigation originated by Flechsig is employed, by which the position and course of various pathways may be determined. A staining method differential for medullated axones alone is apphed to the nervous systems of foetuses of different ages, and pathways meduUated at given stages may be followed from the locality of their origin to their termination. In the later stages, when most of the pathways are medullated and therefore stain alike, the less precocious pathways may be followed by their absence of meduUation.
(3) Direct anatomical evidence. — (a) Stains differential for axones alone are applied to a given locality to determine the fact that the axones of a given bundle actually arise from the cell-bodies there, or that axones traced to a given locality actually terminate about the cellbodies of that looahty. For example, it may be proved anatomically that the axones of a dorsal root arise from the cells of the corresponding spinal ganglion, and then these axones may be traced into the spinal cord and their terminations noted either by collateral or terminal twigs, or the fasciculus they join in their cephalic course may be determined. (6) The staining properties and the size and distribution of the tigroid masses in the cell-bodies of sensory neurones differ from those in the motor neurones, and recently Malone has claimed that, in the central system, the cell-bodies in the nuclei of sensory neurone chains, those ascending toward the cerebral cortex, may be distinguished from the cell-bodies of the motor or descending chains by the arrangement and size of their tigroid masses. He claims further that in the same way, the cellbodies of the somatic efferent neurones may be distinguished from those of the visceral efferent neurones. In this way the locaUty of origin of certain physiologically known paths may be determined.
(4) The so-called paihologico-anatomical method is based upon the same general principles as is the physiological (or experimental) method. A pathological lesion, a local infection or a tumor for example, may destroy a nucleus of cell-bodies or sever a bundle of axones, and the resulting degeneration of the axones may be followed through serial sections suitably prepared. The locahty of the lesion known, the path may be followed to determine the locality of its termination; its locality of termination known from the symptoms resulting, the path may be followed to its cells of origin, or to determine whatever be the locality of the lesion.
Funiculi. — In order that the various fasciculi may be referred to with greater ease, the white substance of the spinal cord in section is divided into three areas known as funiculi or columns and which correspond to the funiculi already mentioned as evident upon the surface of the cord when intact. The funiculi are outlined wholly upon the basis of their position in the cord and with reference to the median line and the contour of the column of grey substance; their component fascicuh are defined upon the basis of function. (1) The 'posterior funiculus or column is bounded by the posterior median septum and the line of the dorsal horn; (2) the lateral funiculus or column is bounded by the lateral concavity of the grey column and the lines of entrance and exit of the dorsal and ventral roots; (3) the ventral funiculus or column is bounded by the Hne of exit of the ventral roots, and by the anterior median fissure.
The posterior funiculus or column [funiculus posterior]. — This funiculus is composed of two general varieties of axones arranged in five fasciculi. First, and constituting the predominant type in all the higher segments of the cord, are the afi'erent or general sensory axones, which arise in the spinal ganglia, enter the cord by the dorsal roots, assume their clistribution to the neurones of the cord, and then take their ascending course toward the encephalon. The axone of the spinal ganglion neurone undergoes a T-shaped division a short distance from the cellbody, one limb of this division terminating in the peripheral organs and the other going to form the dorsal root. Upon entering the cord the dorsal root axones
POSTERIOR FUNICULUS
undergo a Y-shaped bifurcation in the neighbourhood of the dorsal horn, one branch ascending and the other descending. Their ascending branches form the fasciculus gracilis (Goll's column) and the fasciculus cuneatus(Burdach's column). These fasciculi are the chief ascending or sensory spino-cerebral connections, the direct sensory path to the brain. The neurones represented in them constitute the first link in the nem-one chain between the periphery of the bodj'- and the cerebral cortex.
A, shows dorsal root axones DR, entering the spinal cord, bifurcating at B, and giving off collaterals C to the neurones of the cord. B shows the telodendria of these axones or of their collaterals displayed upon cell-bodies of the grey substance of the cord.
In threading their way toward the brain, these sensory axones tend to work toward the midline. Therefore tliose of longer course are to be found nearer the posterior septum, in the upper segments of tlie cord, than those axones which enter the cord by the dorsal roots of the upper segments. Thus it is that the fasciculus gracilis, the medial of the two fasciculi, contains the axones which arise in the spinal ganglia of the sacral and lumbar segments. In other words, it ia the fasciculus bearing sensory impulses from the lower limbs to the brain, while the fasciculus cuneatus, the lateral of the two, is the corresponding pathway for the higher levels. Naturally, there is no fasciculus cuneatus as such in the lower segments of the spinal cord. The axones being mucli blended at first, it is only in the upper thoracic and cervical region that there is any anatomical demarcation between the two fasciculi. In this region the two become so distinct that there is in some cases an apparent connective-tissue septum between them, continuing inward from the postero-intermediate sulcus — the surface indication of the hne of their junction (fig. 616).
Upon reaching the medulla oblongata the fibres of the fasciculus gracilis and the fasciculus cuneatus terminate about cells grouped to form the nuclei of these fasciculi. The nucleus of the fasciculus gracilis is situated medially and begins just below the point at which the central canal opens into the fourth ventricle; the nucleus of the fasciculus cuneatus is placed laterally and extends somewhat higher than the other nucleus. The neurones whose cell-bodies compose these
periphery to the cerebral cortex.
The descending or caudal branches of the dorsal root axones are concerned wholly with the neurones of the spinal cord. They descend varying distances, some of them as much as four segments of the cord, and give off numerous collaterals on their way to the cells of the grey column. Those terminating about cell-bodies of the ventral horn which give rise to the ventral or motor root-fibres, are responsible for certain of the so-called 'reflex activities' and thus contribute to the simplest of the reflex arcs. In descending they serve to associate different levels of the grey substance of the cord with impulses entering by way of a single dorsal root. Some of their collaterals cross the mid-line in the posterior white commissure, and thus become connected with neurones of the opposite side. The caudal branches of longer course are scattered throughout the ventral portion of the fasciculus cuneatus {middle root zone) , and the longest show a tendency to collect along the border-line between the fasciculus cuneatus and the fasciculus gracilis, and thus contribute largely to the comma-shaped fasciculus. Also some of the longest of them in the lower levels course in the oval bundle or septomarginal root zone.
The ascending branches of the dorsal root axones also give off collaterals to the grey substance of the cord, thus extending the area of distribution of a given dorsal nerve-root to levels of the cord above the region at which the root enters.
The greater number of the terminations of dorsal root axones within the spinal cord are concerned first with neurones other than those contributing ventral rootfibres. The greater mass of the neurones concerned are those of the Golgi type II and those contributing the fasciculi proprii or ground bundles of the spinal cord, or the second variety of axones composing the posterior funiculus. The latter fasciculi arise from the smaller cells of the grey column.
These axones pass from the grey substance to enter the surrounding white substance, bifurcate into ascending and descending branches, which in their turn give off numerous collaterals to the cells of the grey substance of the levels through which they pass. The cell-bodies giving origin to such axones are so numerous that the entire column of grey substance is surrounded by a continuous felt-work of axones of this variety.
The dorsal fasciculus proprius (anterior root zone of posterior column) arises chiefly from cells situated in the dorsal horn (slraium zonale). Coincident with the ingrowth and arrangement of the fasciculi gracilis and cuneatus many fibres of the dorsal fasciculus proprius go to form both the oval bundle and the comma-shaped fasciculus. Thus these two bundles are mixed, being fasciculi proprii which contain caudal branches of dorsal root axones. The association fibres in the oval bundle are the longest of any belonging to the dorsal fasciculus proprius. The cephalic and caudal branches combined of some are said to extend more than half the length of the cord and it has been claimed that some even associate the cervical region with the conus meduUaris. Based upon this claim, Obersteiner has called the oval bundle, the "dorso-medial sacral field" and Edinger has referred to the most dorsal part of it as the "tractus cervico-lumbalis dorsalis." The 'median triangle' is formed by the continuation of the dorsal fasciculi proprii with the oval or septo-marginal fasciculus. Some of the axones of the dorsal fasciculus proprius cross the midline to distribute impulses to the neurones of the opposite side. These commissural axones, together with certain collaterals of the dorsal root axones, which cross the mid-line outside the dorsal white commissure, compose the so-called cornu-commissural tract at the base of the posterior septum.
The lateral funiculus or column [funiculus lateralis]. — Not all the axones of the posterior or dorsal nerve-roots extend to the encephalon. Estimation shows that the sum of all the dorsal roots is greatly in excess of the sum contained in the fasciculi cuneatus and gracilis just before these enter their nuclei of termination. Therefore many of the ascending dorsal root axones are concerned with spinalcord relations wholly.
The marginal zone of Lissauer, situated along the lateral margin of the postero-lateral sulcus. is composed largely of dorsal root axones. Many of these finally work across the line of the sulcus into the posterior funiculus. Many of the dorsal root-fibres which do not reach the brain occur in Lissauer's zone. Many others of course occur throughout the posterior column. Lissauer's zone also contains some fibres arising from the small cells of the dorsal horn, and to this extent corresponds to a fasciculus proprius. Ranson has found that large numbers of the non-meduUated dorsal root axones which enter the cord are contributed to Lissauer's zone.
The lateral fasciculus proprius (lateral ground bundle, lateral limiting layer) is situated in the lateral concavity of the grey column and is continuous with the other fasciculi proprii both dorsal and ventral. Beyond that it probably contains
LATERAL CEREBROSPINAL FASCICULUS
fewer commissural axones, it is of the same general significance as the others. It is frequently divided into small bundles by the reticular formation (see fig. 616). The lateral cerebro-spinal fasciculus (crossed p.yramidal tract). In contrast to the sensory fibres passing through the spinal cord conveying impulses destined to reach the cerebral cortex, axones are given off from the pyramidal cells of the
Fig. 618. — Diageam Illustrating the Formation of the Fasciculi Proprii (association fasciculi) and the Commissural Fibres of the Spinal Cord, and the General Architecture OF THE Cord as a Mechanism for Reflex Activities.
The ventral fasciculus proprius is omitted and the lateral is shown on one side only. The lower spinal ganglion neurone shown illustrates the type whose ascending branch is of much longer extent than that of the upper one.
Upon reaching the medulla oblongata in their descent, these axones are accumulated into two well-defined, ventrally placed bundles, the pyramids, one from each cerebral hemisphere. In passing through the brain stem the pyramids contribute many fibres which cross the mid-line to terminate in the motor nuclei of the cranial nerves of the opposite side, and thus decrease appreciably in bulk. According to the estimate of Thompson, only about 160,000 of the pyramidal fibres are destined to enter the spinal cord.
pyramids.' The remainder retain their ventral position in their descent decussating gradually in the cord itself. The pyramidal fibres which cross in the medulla course in the lateral column ventral to Lissauer'sjzone, and lateral to the lateral fasciculus proprius, and form the lateral cerebrospinal fasciculus (crossed pyramidal tract). It is a large fasciculus, oval shaped in transection, and since its axones terminate in the grey column of the cord all along its length, it decreases in bulk as the cord is descended.
In addition to the three dispositions of the dorsal root axones given above, certain of them, either by collaterals or terminal twigs, form telodendria about the cells of the dorsal nucleus (Clarke's column), which nucleus extends from about the seventh cervical to the third lumbar segment of the cord. The axones given off by these cells pass to the dorso-lateral periphery of the lateral funiculus, and there collect to form the dorsal spino-cerebellar fasciculus (direct cerebellar tract of Flechsig). As such they ascend without interruption, and in the upper level of the medulla oblongata pass into the cerebellum by way of the inferior cerebellar peduncle or restiform body. Necessarily, this fasciculus is not evident in levels below the extent of the nucleus dorsalis.
Also situated superficially in the lateral funiculus is another ascending conduction path, and, like the dorsal spino-cerebellar fasciculus, to which it is adjacent, it is also in part at least a cerebellar connection. Its position suggests its name, superficial ventro-lateral spino-cerebellar fasciculus (Gowers' tract).
This tract at'present'does not include as great an area in transverse section as when originally described. The more internal portion of the original Gowers' tract is now given a separate significance, and will be considered separately. While the exact location in the grey column of all the cell-bodies giving origin to the superficial ventro-lateral spino-cerebellar fasciculus is uncertain, it is known that certain ventral horn cells contribute their axones to it. Many of its cells of origin are scattered in the area immediately ventral to the nucleus dorsalis, others in the intermediate and mesial portion of the lateral group of ventral horn cells. In the lumbar region these cells are quite numerous, and, therefore, the fasciculus begins at a lower level in the spinal cord than does the direct cerebellar tract. In degenerations it becomes visible in the upper segments of the lumbar region, and has been proved to increase notably in volume as the cord is ascended. Its axones arise for the most part directly from cell-bodies of the same side of the cord, though it has been shown by several investigators that many of its axones come from the grey substance of the opposite side by way of the ventral white commissure. Terminal twigs and collaterals of the dorsal root-fibres, mostly of the same side, but occasionally from the opposite side, terminate about its cells of origin. At one time Gowers' tract was considered an entity, but now, even in the more Umited area it occupies, it must be considered a mixture of axones of several terminal destinations or distinct neurone systems. The destination of some of its axones has not been determined with certainty. A portion, the spino-cerebellar fasciculus proper, go to the cerebellum, and there have been traced to the cortex of the superior vermis. Most of these reach the cerebellum not by way of the restiform body, as does the dorsal spino-cerebellar tract, but pass on in the brain-stem to the level of the inferior corpora quadrigemina, and there turn back£to join the brachiumjconjunctivum or superior cerebellar peduncle. (Auerbach, Mott, Hoche.) Only a few of its_ axones leave the fasciculus lower down in the medulla, to enter the cerebellum by way of the restiform body, in company with the dorsal spino-cerebellar tract. (Rossolimo, Tschermak.) Another portion of its axones are thought to reach the cerebrum, probably the nucleus lentiformis, though it has not been positively traced further than the superior corpora quadrigemina. Many axones in Gowers' tract of the cord correspond to those of the fasciculi proprii, and merely run varying distances in the cord, to turn again into its grey substance. Schaeffer followed some of these from the lumbar region up to the level of the second cervical nerve.
In the ventro-mesial border of Gowers' tract and immediately upon the periphery, near the antero-lateral sulcus (exit of ventral nerve-roots), there is found in the higher segments of the cord a small oval bundle, the spino-olivary fasciculus or Helweg's (Bechterew's) bundle. The functional direction of its fibres has not been settled.
It is asserted to arise from cell-bodies of the ohve in the medulla oblongata, and in the cord is beheved to be associated with the cells of the ventral column of grey substance, probably those of the lateral; horn. More recent claims assert that it arises fron cell bodies inithe cord and thus is spino-olivary. By some observers it has been traced as far down as the mid-thoracic region; by others, however, only as far as the third cervicalfsegment. The olives being nuclei largely concerned with cerebellar connections, Helweg's fasciculus is probably an indirect cerebellar association with the spinal cord neurones. It is composed of axones of relatively very small diameter, andjt is one of the last fasciculi of the spinal cord to become meduUated.
Situated between the superficial ventro-lateral spino-cerebellar fasciculus and the lateral fasciculus proprius is an area which, in transverse sections, may be, by position, referred to collectively as the intermediate fasciculus. So intermingled are the axones comprising it that it has been called the mixed lateral zone. It contains fibres of at least five functional varieties:
of spinal cord, probably directly with the ventral root or motor neurones.
(3) The rubro-spinal fasciculus. — This arises from cell-bodies in the red nucleus of the tegmentum (in the mesencephalon) and is a crossed fasciculus. Axones arising from the red nucleus of one side cross the mid-Une while yet in the mesencephalon and descend in the lateral funiculus of the cord to terminate gradually about ceU-bodies of the ventral horn, both those which give rise of ventral root fibres and those which contribute to the fascicuU proprii. Its fibres are more thickly bundled in a crescentic area fitting onto the ventral side of the lateral cerebro-spinal fasciculus, and some are said to mix into the area of this latter.
(4) The vestibulo-spinal fasciculus. — This is sometimes called the lateral vestibulo-spinal fasciculus from the fact that there is a tract of similar significance in the ventral funiculus of the cord. It arises from some of the ceU-bodies comprising Deiter's nucleus, the lateral nucleus of termination of the vestibular nerve, and from some of those of the spinal nucleus (nucleus of the descending root) of this nerve, all of which is in the medulla. _ It descends the cord, uncrossed, to terminate gradually about ventral horn cells, thus comprising a part of the apparatus for the equilibration of the body. . Its fibres are thought to be more closely collected in the area immediately ventral to the rubro-spinal fasciculus, but of course commingle with the latter.
(5) The corpora-quadrigemina-thalamus path. The most lateral portion of the intermediate fasciculus, a small area once included in Gower's tract, contains fibres both ascending and descending, connecting the spinal cord with the thalamus (diencephalon) and the quadrigeminate bodies of the mesencephalon. These are crossed paths. The ascending fibres arise from ceUbodies in the ventral horn of one side, cross in the ventral white commissure (commissural neurones) and course upward in the intermediate fasciculus to their termination in the opposite side. Those terminating about cell-bodies in the thalamus form what is known as the spinothalamic tract, while those terminating in the nuclei of the quadrigeminate bodies are called the spino-mesencephalic or spino-tectal tract (Iradus spino-tectalis) . It is not known in which region of the cord most of these fibres arise but it is quite probably the cervical region. The fibres which arise from cell-bodies of the thalamus and nuclei of the quadrigeminate bodies cross the mid-line in the mesencephalon and descend the cord to terminate graduaDy about celliDodies in the ventral horn ol the opposite side. Those from the thalamus are known as the thalamo-spinal tract and those from the quadrigemina, as the mesencephalo- or tecto-spinal tract. The latter is thought to be the larger.
By the fibres of the above tracts general sensory impulses from the body (skin, etc.) are carried to the central portion of the optic apparatus, and the descending fibres give a simple anatomical possibility for the movements of the body in response to visual and auditory impulses. The descending fibres are thought to terminate chiefly in contact with association neurones of the fasciculi proprii, these transferring the impulses to the neurones giving origin to the ventral or motor root fibres, but some are thought to terminate directly about the cellbodies of ventral-root neurones. A portion of the intermediate fasciculus, most adjacent to Gower's tract, has been designated as Loewenthal's tract.
The anterior funiculus or column [funiculus anterior]. — The intermediate fasciculus is continued ventrally and mesially across the line of exit of the ventral root axones, and thus into the anterior funiculus. This portion is also mixed, but its axones of long course associate somewhat different portions of the nerve axis from those connected by the more lateral portion.
According to the studies of Flechsig, von Bechterew, and Held, this mesial portion contains fibres, both ascending and descending, which associate the various levels of the grey substance of the spinal cord with the neurones in the reticular formation of the medulla oblongata. The levels to which they have been traced comprise the olivary nuclei, which are largely concerned in cerebellar connections, and the nuclei of the vagus, glosso-pharyngeal, auditory, facial and the spinal tract of the trigeminus. Also some of the ascending fibres are probably associated with the nuclei of the eye-moving nerves. This portion of the intermediate fasciculus also grades into and is mixed with the axones of the ventral fasciculus proprius, as is its lateral portion with the lateral fasciculus proprius. In other words, the fasciculi proprii proper, the axones nearest the grey substance, serve for the intersegmental association of the different levels ol the grey substance of the cord, while the intermediate fasciculus contains axones of longer course which serve to associate more distant levels of the grey substance of the nerve axis — that of the spinal cord with its upward continuation into the medulla oblongata, pons and mesencephalon.
The anterior marginal fasciculus, ventral vestibulo-spinal tract (Loewenthal's tract) forms the superficial boundary of the mesial portion of the intermediate fasciculus. It is a narrow band, parallel with the surface of the cord, and extends mesially from the mesial extremity of Gowers' tract (from Helweg's bundle) to the beginning of the anterior median fissure.
The axones belonging to it proper are descending from the recipient nuclei of the vestibular nerve. Of these nuclei it has been held by some investigators that only Deiters' nucleus (the lateral nucleus of termination in the upper extremity of the medulla oblongata) gives origin to the axones of the anterior marginal fasciculus. Others agree with Tschermak that the superior and more laterally situated Bechterew's nucleus of the vestibular nerve also contributes axones
to it, and quite probably the nucleus of the spinal root of the vestibular adds further axones. Still other investigations have shown that a part at least of the fasciculus comes from the nucleus fastigius (roof nucleus) of the cerebellum. Since many axones from both Deiters' and Beehterew's nucleus terminate in the nucleus fastigius, the ventral vestibulo-spinal fasciculus
Fig. 620.— Diagram of Spinal Cord Illustrating the Two Chief Varieties of SpinoCEREBRAL AND Cerebro-spinal Neurone Chains. The Ventral tecto-spinal (sulcomarginal) fasciculus, fibres descending from the superior quadrigeminate bodies, is not filled in.
IS, in any case, a conduction path from the nerve connections for equilibration to the grey substance of the spinal cord. The fasciculus is said to extend as far as the sacral region of the cord, its axones terminating about the cells of the ventral horns. The term "ventral" is added to its name to distinguish it from the vestibulo-spinal tract described above as coursing in the lateral funiculus. It is considered an uncrossed pathway.
The ventral cerebro-spinal fasciculus (anterior or direct pyramidal tract), as stated above, is the uucrossed portion of the descending cerebro-spinal system of nem-ones. It is a small, oblong bundle, situated mesially in the anterior funiculus, parallel with the anterior median fissure. Like the lateral cerebro-spinal fasciculus (crossed pyramidal tract), its axones arise from the large pyramidal cells of the motor area of the cerebral cortex, and transmit their impulses to the neurones of the ventral horns of the grey substance of the spinal cord, and almost entirely to those ne.urones which give origin to the ventral or motor root fibres.
It represents merely a delayed decussation of the pyramidal fibres, for instead of crossing to the opposite side in the lower portion of the medulla oblongata, as do the fibres of the lateral fasciculus, its fibres decussate all along its course, crossing in the ventral white commissure and in the commissural bundle of the cord to terminate about the ventral horn cells of the opposite side. Hoohe, employing Marchi's method, found that a few of its fibres terminate in the ventral horn of the same side. This conforms to the pathological and experimental evidence that there are homolateral or uncrossed fibres in the crossed pyramidal tracts also. Like the crossed tract, the ventral pyramidal tract diminishes rapidly in volume as it descends the cord. Its loss is greatest in the cervical enlargement, and it is entirely exhausted in the thoracic cord. With the exception of the anthropoid apes and certain monkeys, none of the mammalia below man, which have been investigated, possess this ventral pyramidal tract
Lying between the ventral cerebro-spinal fasciculus and the pia mater of the anterior median fissure is a thin tract of descending axones continuous ventrally with the anterior marginal fasciculus. From its position it is known as the sulcomarginal fasciculus; functionally it is the ventral mesencephalo-spinal (tectospinal) tract.
The extent of its course in the spinal cord is uncertain. It arises from the cells of the grey substance of the superior pair of the quadrigeminate bodies, and there, in largest part at least, it crosses the mid-line, and in the so-called 'optic acoustic reflex path' descends through the medulla oblongata into the spinal cord of the opposite side. The superior quadrigeminate bodies having to do with sight, this tract forms a second path conveying visual impulses to the neurones of the spinal cord.
The commissural bundle is situated about the floor of the anterior median fissm-e, and is the most dorsal tract of the anterior funiculus. It contains decussating or commissural axones of three varieties.
(1) It contains the decussating axones of the ventral cerebro-spinal fasciculus throughout the extent of that fasciculus; (2) it is chiefly composed of the axones of the ventral fasciculus proprius which arise in the grey substance (ventral horn) of one side, cross the mid-line as commissural fibres, and course both upward and downward to be distributed to the neurones of different levels of the grey substance of the opposite side; (3) it contains decussating axones which arise from cell-bodies in the grey substance of one side and cross the mid-line to terminate about cell-bodies in practically the same level of the opposite side. The latter are merely axones belonging to the ventral white commissiu-e which course without the confines of the grey figure. The commissural bundle is present throughout the length of the spinal cord, and is largest in the enlargements, i. e., where the association and commissural neurones occur in greater number generally. In its two last-mentioned varieties of axones it corresponds to the commissural portion of the dorsal fasciculus proprius (the cornu-commissural bundle).
The spinal cord contains two general classes of axones arranged into three general systems. It contains axones which — (a) enter it from cell-bodies situated outside its boundaries, i. e., in the spinal ganglia and in the encephalon, and (b) axones which arise from cell-bodies situated within its own grey substance, some of which axones pass outside its boundaries both to the periphery and into the encephalon; some of which remain wholly within it. Its axones comprise — (1) a system for the intersegmental association of its grey substance, both ascending and descending, association proper and commissural; (2) a spino-cerebral and cerebro-spinal system, ascending and descending; and (3) a spino-cerebellar and cerebello-spinal system, ascending and descending.
For these relations the grey substance of the cord contains three general classes of nerve-cells: — those which give rise to the peripheral efferent or motor axones of the ventral roots; those which give rise to central axones of long course, going to the encephalon; and those which supply its central axones of shorter course, the association and commissural systems.
The three systems : (1) Association and commissural. — Axones of spinal ganglion (afferent) neurones bifurcate within the cord into cephalic and caudal branches which extend varying distances upward and downward and terminate, (a) about cell-bodies whose axones are short and terminate within the grey substance of the same side and in the same level as their cellbodies {Golgi neurones of type II); (b) about ceO-bodies whose axones pass without the grey substance, bifurcate into cephalic and caudal branches to terminate in the grey substance of the same side but in various levels above and below (association fibres in the dorsal, lateral and ventral fasciculi proprii); (c) about cell-bodies whose axones cross the mid-line to terminate either in the same level of the grey substance of the opposite side, or bifurcate and the cephalic and caudal branches pass in the fasciculi proprii to terminate in various levels of the grey substance of the opposite side. The longer cephalic branches of (b) and (c) may terminate in the meduUa oblongata. All, associated with ventral root (efferent) neurones, belong to the neurone chains for the so-oaOed reflex activities.
(2) The cerebral system. — (a) The cephalic branches of certain spinal ganglion neurones ascend beyond the bounds of the spinal cord to terminate within the medulla. Those ascending from the spinal ganglia of lower thoracic and lumbo-sacral segments accumulate mesiaUy to form the fasciculus gracilis which terminates in the nucleus of this fasciculus; those arising from the upper thoracic and cervical segments accumulate more laterally in the posterior funiculus to form the fasciculus cuneatus which terminates in the nucleus of the fasciculus cuneatus. (6) The impulses transferred to the neurones of these nuclei are borne across the mid-line and finall}' reach the sensory-motor area of the cerebral cortex, and cell-bodies here give rise to axones which descend, some decussating in the medulla to form the lateral cerebrospinal fasciculus, others form the uncrossed ventral cerebrospinal fasciculus which crosses the mid-line as it descends the cord. Both of these fasciculi transfer their impulses either directly to efferent ventral horn neurones, or to association neurones and these to the efferent neurones, (c) The cephalic and caudal branches of spinal ganglion neurones terminate about cell-bodies in the grey substance of the cord whose axones cross the mid-line and ascend laterally to terminate either in the quadrigeminate bodies {spino-mesencephalic tract), or in the thalamus (spino-thalamic trad), (d) Cell-bodies in thalamus and superior quadrigeminate bodies (receiving optic impulses) and in the inferior quadrigeminate bodies (probably mediating auditory impulses), give axones which cross the mid-line in the mesencephalon and descend, forming the thalamospinal and mesencephalospinal tracts, to terminate in contact with the efferent neurones of the cord. Axones from both sources descend in the lateral funiculus, while from the superior quadrigeminate body, a separate bundle descends in the ventral funiculus as the sulco-marginal {ventral mesencephalospinal) fasciculus, (e) The rubrospinal tract arises from cell-bodies in the red nucleus (in the mesencephalon), crosses the mid-line and descends in the lateral funiculus to transfer (probably cerebellar) impulses to the efferent neurones of the spinal cord.
(.3) The cerebellar system. — (a) The cephalic and caudal branches of spinal ganglion neurones give telodendria about the cell-bodies forming the dorsal nucleus of the cord (Clarke's column) and about cell-bodies situated in grey substances ventral to the dorsal nucleus ("Stilling's nucleus") and in the lateral horn. Axones arising from the cells of the dorsal nucleus pass laterally to form the dorsal spino-cerebellar fasciculus which ascends into the cerebellum by way of its inferior peduncle of the same side and terminates about cell-bodies of its cortex. Axones arising from Stilling's nucleus and the lateral horn cells, of both the same and opposite sides of the cord, accumulate to form the superficial venlro-lateral spino-cerebellar fasciculus, which ascends to enter the cerebellum by way of its superior peduncle and terminate about the cells of the cerebellar cortex, (b) A few axones arising in the roof nucleus of the cerebellum probably descent? in the animor marginal fasciculus in company with the ventral vestibulospinal tract to terminate upon the efferent neurones of the cord, (c) The inferior olivary nucleus, in the medulla, is a cerebellar relay and its cell-bodies are associated with the neurones of the upper portion of the same side of the spinal cord. Whether the axones arise in the olivary nucleus or in the grey substance of the cord is uncertain, but the more usual supposition favours the cord and thus the name, spino-olivary fasciculus is given them, (rf) Among its other functions, the cerebellum is concerned with equilibration. The vestibular nerve is the afferent nerve of equilibration and a large mass of the axones arising from its nuclei of termination terminate in the cerebellum, in the roof nuclei especially. Axones arising from cell-bodies in Deiters' nucleus (its lateral nucleus of termination) and in the nucleus of its descending root descend the cord in the lateral funiculus to form the (lateral) vestibulospinal tract, and also in the anterior marginal fasciculus to form ventral vestibulospinal tract. Impulses borne by these axones reach the efferent or motor root neurones. The rubro-spinal fasciculus, mentioned above also may be possibly considered as belonging to the cerebellar system.
Sympathetic relations. — The cell-bodies of the efferent neurones in the ventral horns are of two general varieties: (a) those whose axones terminate upon skeletal muscle (somatic efferent), and (6) those whose axones terminate in contact with cell-bodies of sympathetic neurones, the splanchnic or visceral efferent neurones. The axones of the sympathetic neurones, in their turn, terminate upon cardiac and smooth muscle (motor) and in glands (secretory). Like the somatic, the visceral efferent neurones receive impulses within the ventral horns (a) from the cephalic and caudal branches of spinal ganglion neurones, (b) the descending cerebro-spinal fasciculi, and (c) from either, by way of the fasciculi proprii and Golgi neurones of type II. Their cell-bodies are situated for the most part in the dorsal portion of the lateral horn (dorso-lateral group of cells), which is the only portion of the lateral horn present in the thoracic region of the cord. Many of the visceral efferent fibres leave the spinal nerves distal to the spinal ganglia and make the white communicating rami, thus going to the nearest sympathetic ganglia; others pass on in the spinal nerve and its branches to terminate in more distal sympathetic ganglia. Dogiel has described axones which arise in sympathetic ganglia and terminate upon the ceU-bodies of the spinal ganglia. Such convey sensory impulses which, however, enter the spinal cord by way of the dorsal root branch of the spinal ganglion neurone. Such afferent sympathetic neurones are relatively rare, the peripheral distribution of the ordinary
c, collaterals of a and b disposed in three ways; p, pyramidal axone in lateral (crossed) cerebro-spinal fasciculus distributed to levels of grey substance; pa, axone in ventral cerebrospinal fasciculus decussating before termination; v, ventral root or motor neurones; n, nucleus dorsalis giving axone to dorsal spino-oerebellar fasciculus; g, ascending neurones of Gowers' tract; d, descending axone from cerebellum (probable); fp, neurones of fasciculi proprii, association proper; h, commissural neurones; e, Golgi cell of type II.
axones.
In transverse sections of the spinal cord, the relative area of white substance as compared with that of grey increases as the cord is ascended. The absolute area of each varies with the localitj^, both being greatest in the enlargements. The grey substance predominates in the conus medullaris and lower lumbar segments. The white substance begins to predominate in the upper lumbar segments, not because of the increased presence of ascending and descending cerebral and cerebellar axones, but because of the increased volume of the fasciculi proprii coincident with the greater mass of grey substance to be intersegmentally associated in this region. In the thoracic region the greatly predominating white substance
CERVICAL THORACIC LUMBAR SACRAL
is composed mostly of the axones of long course. The greatly increased absolute amount of white substance in the cervical region is due both to the greater accumulation of cerebral and cerebellar axones in this region and to the increased volume of the fasciculi proprii of the cervical enlargement.
ORDER OF MEDULLATION OF THE FASCICULI OF THE CORD
The axones of the spinal cord begin to acquire their myehn sheaths during the fifth month of intra-uterine hfe and myehnization is not fuUy completed till between the fifteenth and twentieth years. In general, axones which have the same origin and the same locality of termination — ■ the same function — acquire their sheaths at the same time. While it has been proved that the medullary sheath does not necessarily precede the functioning of an axone, it may be said that those fasciculi which first attain complete and definite functional ability are the first to become medullated. At birth all the fascicuh of the spinal cord are meduUated except Helweg's fasciculus, and occasionally the lateral and ventral cerebro-spinal tracts. The latter tracts vary considerably and in general may be said to become medullated between the ninth month (before birth) and the second year. As indicated by their meduUation, those axones by which the cord is enabled to function as an organ per se, that is, the axones making possible the simpler reflex activities, complete their development before those axones which involve the brain with the activities of the cord.
proprius.
(3) The fasciculus cuneatus (Burdach's column) and Lissauer's zone — the area of tho.se ascending spino-cerebral fibres which run the shorter course and which convey impulses from the upper limbs, thorax and neck.
The axones descending from the cerebellum and the brain-stem are so mixed with other axones that it is difficult to determine the sequence of their medullation. The fasciculi contaiaing them also contain axones of the variety in the fasciculi proprii and so show medullation early. It is probable that the ascending, spino-cerebellar, fibres acquire their myeUn earlier than the descending, if descending exist.
Blood Supply of the Spinal Cord
The spinal rami of the sacral, lumbar, intercostal, or vertebral arteries, as the case may be, accompany the spinal nerves through the intervertebral foramina, traverse the dura mater and arachnoid, and each divides into a dorsal and a ventral radicular artery. These accompany the nerve-roots to the surface of the cord, and there break up into an anastomosing plexus in the pia mater. From this plexus are derived three tortuously coursing longitudinal arteries and! numerous independent central branches, which latter penetrate the cord direct. Of the longitudinal arteries, the anterior spinal artery zigzags along the anterior median fissure and gives off the anterior central branches, which pass into the fissure and penetrate the cord. These branches give ofT a few twigs to the white substance in passing, but their most partial distribution is to the ventral portion of the grey substance. The two posterior spinal arteries, one on each side, course near the hnes of entrance of the dorsal root-fibres. They each branch and anastomose, so that often two or more posterior arteries may appear in section upon either side
of the dorsal root. These give off transverse or central twigs to the white substance, but especially to the grey substance of the dorsal horns. Of the remaining central branches many enter the cord along the efferent fibres of the ventral roots, and are distributed chiefly to the grey substance; others from the peripheral plexus throughout penetrate the cord and break up into capillaries within the white substance. Some of the terminal twigs of these also enter the grey substance. The blood supply of the grey substance is so much more abundant than that of the white substance that in. injected preparations the outline of the grey figure may be easily distinguished by its abundance of capillaries alone. The central branches are of the terminal variety. In the white substance the capillaries run for the most part longitudinally, or parallel with the axones.
The venous system is quite similar to the arterial. The blood of the central arteries is collected into corresponding central venous branches which converge into a superficial venous plexus in which are six main longitudinal channels, one along the posterior median sulcus, one along the anterior median fissure, and one along each of the four lines of the nerve-roots. These comprise the posterior and anterior external spinal veins (fig. 623).
The internal spinal veins course along the ventral surface of the grey commissure, and arise from the convergence of certain of the twigs of the anterior central vein. The posterior central vein courses along the posterior median septum in company with the posterior central artery, and empties into the median dorsal vein. The venous system communicates with the coarser extra-dural or internal vertebral plexus chiefly by way of the radicular veins.
II. THE BRAIN OR ENCEPHALON
The brain is that greatly modified and enlarged portion of the central nervous system which is enclosed within the cranial cavity. It is surrounded and supported by the same three membranes (meninges) that envelop the spinal cord.
cavity than does the spinal cord.
The average length of the brain is about 165 mm. and its greatest transverEe diameter about 140 mm. It averages longer in the male than in the female. Exclusive of its dura mater, the normal brain weighs from 1100 to 1700 gm. (40-60 oz.), varying in weight with the stature of the individual or with the bulk of the tissues to be innervated. Its average weight is 1360 gm. (48 oz.) in males and 1260 gm. (44 oz.) in females. It averages about fifty times heavier than the spinal cord, or about 98 per cent, of the entire cerebro-spinal axis. In its precocious growth it is at birth relatively much larger than at maturity. At birth it comprises about 13 per cent, of the total body-weight, while at maturity it averages only about 2 per cent of the weight of the body. Its specific gravity averages 1.036. In proportion to the bodyweight the brain-weight averages somewhat higher in smaller men and women. Some very small dogs and monkeys and some mice have brains heavier in proportion to body-weight than man.
The minimal weight of the adult brain compatible with human intelligence may be placed at from 950 to 1000 grams. Above the minimal, there is only a general relation between the degree of intelligence and the weight of the brain, owing to the fact that several factors may be coincident with large brains. It may be said in general, however, that the average brain weight of eminent men is above the general average. Some men judged eminent have had brains weighing less than the general average. Of the records generally accepted, the greatest brain weight
for eminent men is 2012 grams, recorded for the poet and noveUst, Ivan Tourgenieff. The trustworthiness of this weighing is doubted by some authorities. From the undisputed records the following may be taken: Cuvier, 1830 grams; John Abercrombie, 1786 grams; Thackery, 1658 grams; Kant, 1600 grams; Spurzheim, 1559 grams; Daniel Webster, 1518 grams; Louis Agassiz, 1495 grams; Dante, 1420 grams; Helmholtz, 1440 grams; Goltz, 1395 grams; Liebig, 1352 grams; Walt Whitman, 1282 grams; Gall, 1198 grams. In the average brain weights for the races that for the Caucasian stands highest, the Chinese standing next, then the Malay, followed by the Negro, with the AustraUan lowest.
The differences between the meninges of the brain and those of the spinal cord occur chiefly in the dura mater. (1) The dura maler is about double the thickness of that of the spinal cord, and consists of two closely adhering layers, the outermost of which serves as the internal periosteum of the cranial bones, while that of the cord is entirely separate from the periosteum lining the vertebral canal. (2) The inner layer is duplicated in places into strong partitions which extend between the great natural divisions of the encephalon. Of these, the sickleshaped ialx cerebri extends between the hemispheres of the cerebrum, the crescentic tentorium cerebelli extends between the cerebellum and the overlapping posterior portion of the cerebrum, and the smaller falx cerebelli occupies the notch between the hemispheres of the cerebellum. Contained within these partitions of the dura mater are the great collecting venous sinuses of the brain. These will be considered in the more detailed description of the cranial meninges.
Viewed from above, the cerebrum comprises almost the entire dorsal aspect, the occipital lobes overlapping the cerebellum to such an extent that only the lateral and lower margins of the cerebellar hemispheres are visible. The great longitudinal fissure of the cerebrum separates the cerebral hemispheres.
Laterally the temporal lobes, with their rounded anterior extremities, the temporal poles, are each separated from the frontal and parietal lobes above by the lateral cerebral fissure (fissme of Sylvius) . In the depths of this fissure and overlapped by the temporal lobe is situated the insula, or island of Reil (central lobe).
The surface of each cerebral hemisphere is thrown into numerous folds or curved elevations, the gyri cerebri or convolutions, which are separated from each other by slit-like fissures, the sulci cerebri. The gyri (and sulci) vary greatly in length, in depth, and in their degrees of curvature. The larger and deeper of them are similar in the two hemispheres; most of them are individually variable, but each gyrus of one hemisphere is homologous with that of the like region of the other hemisphere. By gently pressing open the great longitudinal fissure, the corpus callosum, the chief commissural pathway between the cerebral hemispheres, may be seen. The occipital margin of this large transverse band of white substance is rounded and thickened into the splenium of the corpus callosum, while its frontal margin is curved ventrally into its genu and rostrum.
The base of the encephalon (fig. 625) is more irregular than the convex surface, and consists of a greater variety of structures. In the mid-line between the frontal lobes appears the anterior and inferior extension of the great longitudinal fissure. When the margins of this are separated, the outer aspect of the rostrum of the corpus callosum, the downward continuation of the curve of the genu, is exposed.
occupy this concave area.
The cranial nerves [nervi cerebrales]. — Along the mesial border of each orbital area, and parallel with the great longitudinal fissure, lie the olfactory bulbs continued into the olfactory tracts. Each olfactory bulb is the first central connection or the ' nucleus of reception' of the olfactory nerve, the first of the cranial nerves. A few fine filaments of this nerve may often be discerned penetrating the ventral surface of the bulb. The olfactory bulb and tract lies in the olfactory sulcus, which forms the lateral boundary of the gyrus rectus, the most mesial gyrus of the inferior surface of the frontal lobe. Upon reaching the area of Broca (area parolfactoria), or the region about the medial extremity of the gyrus rectus, each olfactory tract undergoes a slight expansion, the olfactory tubercle, and then divides into tliree roots or olfactory striae — a medial, an intermediate, and a lateral, which comprise the olfactory trigone. The striae begin their respective courses upon the anterior perforated substance, an area which contains numerous small foramina through which the antero-lateral group of central cerebral arteries enters the brain. This region forms the anterior boundary of that area of the base of the encephalon in which the substance of the brain becomes continuous across the mid-line.
At the medial boundary of the anterior perforated substance the optic nerves come together and fuse to form the optic chiasma. Thence the optic tracts disappear under the poles of the temporal lobes in their backward course to the thaiami and the geniculate bodies or metathalami.
Immediately behind the optic chiasma occurs that diverticulum from the floor of the third ventricle known as the tuber cinereum. It is connected by its tubular stalk, the infundibulum, with the hypophysis or pituitary body, which occupies its special depression (sella turcica) in the floor of the cranium and is usually torn from the encephalon in the process of its removal. Behind the tuber cinereum are the two mammillary bodies (corpora albicantia), each of which is connected with the fornix, one of the larger association fasciculi of the cerebrum. The peduncles of the cerebrum (crura cerebri) are the two great funiculi which associate the cerebral hemispheres with all the structm-es below them. They diverge from the anterior border of the pons (Varoli) and, one for each hemisphere, disappear under the poles of the temporal lobes. The pons (brachium pontis or middle cerebellar peduncle) is chiefly a bridge of white substance or a commissure between the cerebellar hemispheres.
mammillaria.
Tlie trochlear nerves emerge around the lateral aspects of the pedunculi cerebri along the anterior border of the pons. The trochlear is the smallest of the cranial nerves, and the only pair arising from the dorsal aspect of the brain.
The trigeminus, or fifth cranial nerve, is the largest. It penetrates the pons to find its recipient nuclei in the depths of the brain-stem. It is a purely sensory nerve, but it is accompanied by the much smaller masticator nerve which is motor and is usually referred to as the motor root of the trigeminus.
Five pairs of cranial nerves are attached to the brain-stem along the inferior border of the pons: — the abducens nerve, which is motor, emerges near the mid-line; the facial, motor, emerges from the more lateral aspect of the brainstem ; the glosso-palatine or the intermediate nerve of Wrisberg, largely sensory, is attached in company with the facial; and, entering the extreme lateral aspect of the stem are the cochlear and vestibular nerves. These latter two, when taken together as one, are known as the acoustic (auditory) or eighth cranial nerve. They are both purely sensory. The cochlear courses for the most part laterally and dorsally around the inferior cerebellar -peduncle, giving it the appearance from which it derives its name, 'restiform body.'
The remaining four pairs of the cranial nerves are attached directly to the medulla oblongata. This comprises that portion of the brain-stem beginning at the inferior border of the pons above, and continuous with the first segment of the spinal cord below. On its ventral surface the pyramids and the olives (olivary bodies) are the two most prominent structures. The pyramids, which are continuous below into the pyramidal (cerebro-spinal) tracts of the spinal cord, form the two tapering prominences along either side of the anterior median fissure; the olives are the oblong oval elevations situated between the pyramids and the resti-
The glosso-pharyngeal, the vagus (pneumogastric), and the spinal accessory cranial nerves are attached along the lateral aspect of the medulla oblongata in line with the facial nerve and between the olive and the restiform body. The spinal accessory, purely motor, is assembled from a series of rootlets which emerge from the lateral aspect of the first three or four cervical segments of the spinal cord, as well as from the medulla. It becomes fully formed before reaching the level of the olive, and passes lateralward in company with the vagus and further on joins the latter in part. The root filaments of the vagus and glossopharyngeal are arranged in a continuous series, and, if severed near the surface of the medulla, those belonging to the one nerve are difficult to distinguish from those belonging to the other. Both of these are mixed motor and sensory.
The hypoglossal, purely motor, emerges as a series of rootlets between the pyramid and the olive. Thus it arises nearer the mid-line, and in line with the abducens, trochlear, and oculomotor.
If the occipital lobes be lifted from the superior surface of the cerebellum and the tentorium cerebelli removed, the quadrigeminate bodies of the mid-brain or mesencephalon may be observed. These are situated above the cerebral peduncles, in the region of the ventral appearance of the oculomotor and trochlear nerves. Resting upon the superior pair of the quadrigeminate bodies [colliculi superiores] is the epiphysis or pineal body, and just anterior to this is the cavity of the third ventricle, bounded laterally by the thalami and roofed over by the tela chorioidea of the third ventricle (velum interpositum) .
By separating the inferior margin of the cerebellum from the dorsal surface of the medulla oblongata the lower portion of the fourth ventricle (rhomboid fossa) may be seen. The cisterna cerebello-meduUaris, the subarachnoid space in this region, is occupied in part by a thickening of the arachnoid. This is continuous with the tela chorioidea (ligula) and chorioid plexus of the fourth ventricle. The former roofs over the lower portion of the fourth ventricle, and, passing through it in the medial fine, is the lymph passage, the foramen of Magendie, by which the cavity of the fourth ventricle communicates with the subarachnoid space. The fourth ventricle, as it becomes continuous with the central canal of the spinal cord, terminates in a point, the calamus scriptorius. From the inferior surface, the cerebellar hemispheres are more definitely demarcated, and between them is the vermis or central lobe of the cerebellum.
Divisions of the encephalon. — The encephalon as a whole is developed from a series of expansions, flexures, and thickenings of the wall of the cephalic portion of the primitive neural tube, the three primary brain vesicles. Being continuous with the spinal cord, it is arbitrarily considered as beginning just below the level of the decussation of the pyramids, or at a line drawn transversely between the decussation of the pyramids and the level of the first pair of cervical nerves.
In its general conformation four natural divisions of the brain are apparent: the two most enlarged portions — (1) the cerebral hemispheres and (2) the cerebellum; (3) the mid-brain (mesencephalon) between the cerebral hemispheres and the cerebellum, and (4) the medulla oblongata, the portion below the pons and above the spinal cord (fig. 602). However, the most logical and advantageous arrangement of the divisions and subdivisions of the encephalon is on the basis of their development from the walls of the embryonic brain vesicles. (See fig. 598.) On this basis, for example, both the medulla oblongata and the cerebellum with its pons are derived from the posterior of the primary vesicles, and are, therefore, included in a single gross division of the encephalon, viz., the rhombencephalon. In the following outline the anatomical components of the encephalon are arranged with reference to the three primary vesicles from the walls of which they are derived, and the primary flexures and thickenings of the walls of which they are elaborations.
During the early growth of the neural tube its basal or ventral portion and the lateral portions acquire a greater thickness than the roof of the tube, and thus the tutpe is longitudinally divided into a basal or ventral zone and an alar or dorsal zone. This is especially marked in the brain vesicles. Structures arising from the dorsal zone begin as localised thickenings of the roof. For example, in the rhombencephalon the greater part of the medulla oblongata and of the pons region is derived from the ventral zone, while the cerebellum is derived from the dorsal zone. The first of the flexures occurs in the region of the future mesencephalon, and is known as the cephalic flexure; next occurs the cervical flexure, at the junction with the spinal cord;
MEDULLA OBLONGATA
third, the pontine flexure, in the region of the future fourth ventricle. Both the cervical and pontine flexures, while having a significance in the growth processes, are almost entirely obliterated in the later growth of the encephalon.
The location of the development of the various parts of the encephalon may be determined, and their elaboration and changes in shape and positionmay be traced by comparing the accompanying figs. 626, 627, 628. The reference numbers in
Infundibulum
the last three figures correspond with the like numerals after the names of the parts on p. 797 in the outline of the divisions of the encephalon. The more detailed subdivisions of the parts will be met with in their individual descriptions.
The medulla oblongata [myelencephalon] is the upward continuation of the spinal cord. It is only about 25 mm. long, extending from just above the first cervical nerve (beginning of the first cervical segment of the spinal cord) to the inferior border of the pons. It lies almost wholly within the cranial cavity, resting upon the superior surface of the basal portion of the occipital bone, with its lower extremity in the foramen magnum. Its weight is from 6 to 7 gm. or about onehalf of one per cent of the whole cerebro-spinal axis. It is a continuation of the spinal cord, and more. It contains structures continuous with and homologous to the structures of the spinal cord, and in addition it contains structures which have no homologues in the spinal cord. Due in part to these additional structures, the medulla, as it approaches the pons, rapidly expands in both its dorsoventral and especially in its lateral diameters. With it are associated nine of the pairs of cranial nerves.
On its anterior or ventral aspect the anterior median fissure of the spinal cord becomes broader and deeper because of the great height attained by the pyramids. At the level at which the pyramids emerge from the pons, the region in which they are largest, the fissure terminates in a triangular recess so deep as to merit the name foramen caecum. The pyramids are the great descending cerebral or motor funiculi. In the medulla oblongata they decrease in bulk in passing toward the spinal cord, for the reason that many of the pyramidal axones are contributed to structm-es of the medulla, chieflj^ after crossing the mid-line. At the lower end of the medulla occurs the decussation of the pyramids, by which the anterior median fissure is almost obliterated for about 6 mm., and which, upon removal of the pia mater, may be easily observed as bundles of fibres interdigitating obliquely across the mid-line.
and continue directly into the spinal cord, to form there the ventral cerebro-spinal fasciculus or direct pyramidal tract. However, most of such fibres finally cross the mid-line during their course in the spinal cord. The exact proportion of the direct fibres is variable, but always the greater mass of each pjrramid crosses to the opposite side at the level of the decussation of the pyramids, and descends the cord as the lateral cerebro-spinal fasciculus or crossed pyramidal tract. Both of these pjnramidal tracts are described in the discussion of the fascicuU of the cord.
Decussation of pyramids
Each pyramid is bounded laterally by the antero-lateral sulcus, also continuous with that of the same name in the spinal cord. Toward the pons this sulcus separates the pyramid from the olive [oliva] (inferior olivary nucleus), and in the region of the olive there emerge along this sulcus the root filaments of the hypoglossal nerve. These are in line with the filaments of the ventral roots of the spinal nerves. The olives, as their name implies, are oblong oval eminences about 1.2 cm. in length. They extend to the border of the pons, and are somewhat thicker at their upper ends. Their surfaces are usually smooth, except at their lower ends, where they frequently appear ribbed, owing to bundles of the external arcuate fibres passing across them to and from the restiform body, which occupies the extreme lateral portion of the medulla. Along the line between the restiform body and the olive are attached .the root filaments of the vagus, glosso-'pharyngeal, and spinal accessory nerves. Both the abducens and the facial nerve emerge along the inferior border of the pons, the facial in line with the glosso-pharyngeal, but the abducens in line with the hypoglossus.
below it.
In toto, the restiform bodies are much larger than could be formed by the combined cerebellar fasciculi of the spinal cord, their great size being due to their receiving numerous axones coursing in both directions, which connect the cerebellum with structures contained in the medulla oblongata alone, so that in the medulla they increase as they approach the cerebellum. Their mesial borders form the lateral boundaries of the fourth ventricle. Their name (resliform, meaning rope-hlie) was suggested from the appearance frequently given them by the fibres of the cochlear (acoustic division of the eighth) nerve, which course around their lateral periphery to become the strice medullares in the floor of the fourth ventricle.
Upon removal of the cerebellum it may be seen that below the calamus scriptorius (inferior terminus of the fourth ventricle) the structures manifest in the dorsal surface of the medulla are directly continuous with those of the spinal cord. The fasciculus gracilis (Goll's column) of the spinal cord acquires a greater height and volume and becomes the funiculus gracilis of the medulla, and because of this increased height the posterior median sulcus of the cord becomes deepened into the posterior median fissure. The posterior intermediate sulcus is also accentuated by the fasciculus cuneatus (Burdach's column) likewise now enlarged into the funiculus cuneatus of the medulla. The lateral funiculus of the medulla, of course, does not contain the lateral or crossed pyramidal tract present in the spinal cord.
At the border of the calamus scriptorius the funiculus gracilis terminates in a slight elevation, the clava, which is the superficial indication of the nucleus of the fasciculus gracilis. Beginning somewhat more anteriorly, and having a somewhat greater length, is a similar enlargement of the funiculus cuneatus, the tuberculum cuneatum or nucleus of the fasciculus cuneatus.
These nuclei are the groups of nerve cell-bodies about which the ascending or sensory axones of the respective fasciculi terminate or where the sensory impulses are transferred to a second neurone in their course to the structui-es of the encephalon. These cell-bodies in their turn give off axones which immediately cross the mid-line and assume a more ventral position, contributing largely to the lemniscus or fillet of the opposite side, and thus such axones are the encephalic continuation of the central sensory pathway conveying impulses from the periphery of one side of the body to the opposite side of the cerebrum. The crossing of these axonesjis known as the decussation of the lemnisci.
With the termination of the dorsal funiculi and the ventral course of the fibres of the lemnisci in their decussation, the central canal of the spinal cord loses its roof of nervous tissue in the medulla and comes to the surface as the fourth ventricle. The floor of the fourth ventricle, which corresponds to the floor of the central canal, is considerably widened into two lateral recesses opposite the junction of the inferior and middle cerebellar peduncles of either side, and, being pointed at both its superior and inferior extremities, it is rhomboidal in shape and thus is the rhomboid fossa. The pia mater of the spinal cord is maintained across the tip of the calamus scriptorius to form the obex, a small, semilunar lamina roofing over the immediate opening of the central canal. The obex carries a few medullated commissural fibres. . '
2. THE PONS
The pons (Varoli) is, for the most part,- a great commissure or 'bridge' of white substance coursing about the ventral aspect of the brain-stem, and connecting the cerebellar hemisphere of one side with that of the other. In addition it contains fibres passing both to and from the structures of the brain-stem and the grey substance of the cerebellum, and fibres descending from the cerebral cortex. Each of its lateral halves forms the middle of the three cerebellar peduncles, the hrachium pontis of either side.
In size it naturally varies directly with the development of the cerebellum, both in a given animal and relatively throughout the animal series. In man it attains its greatest relative size, and possesses a median or basilar sulcus in which lies the basilar artery. Its sagittal dimension varies from 25 to 30 mm., while its transverse dimension (longitudinal with the course of its fibres) is somewhat greater. It is a rounded white prominence interposed between the visible portion of the cerebral peduncles (crura) above and the medulla oblongata below. Its inferior margin is rounded to form the inferior pontine sulcus, which, between the points of the emergence of the pyramids, is continuous with and transverse to the foramen cjecum. Its superior margin is thicker and is rounded to form the superior pontine sulcus, which, between the cerebral peduncles, is continuous with and transverse to the interpeduncular fossa. (See fig. 629.) It is bilaterally symmetrical. The ventro-lateral bulgings of its sides (and, therefore, the basilar sulcus) are produced by the passage through it of the fibres of the cerebral peduncles from above, to reappear as the pyramids below. Its ventral surface rests upon the basilar process of the occipital bone and the dorsum sellse of the sphenoid, while its lateral surfaces are adjacent to the posterior parts of the petrous portions of the temporal bones.
The fibres of the thicker superior portion of the pons (Jasciculus superior pontis) course obliquely downward to their entrance into the brachium of the pons and the cerebellar hemisphere; those of the lower and mid-portions (Jasciculus medius pontis) course more transversely, naturally converging upon approaching the cerebellum. Certain fibres of the upper midportion course at first transversely and then turn abruptly downward across the fibres above them, to join the inferior portion of the brachium pontis. This bundle is termed the oblique fasciculus (fig. 629). The trigeminus or fifth cranial nerve penetrates the superior lateral portion of each brachium pontis near the point of the downward turn of the obhque fasciculus; its large afferent root and the masticator nerve (its small efferent root) accompany each other quite closely. On either side of the basal surface of the pons usually may be seen a small bundle of fibres which begins in the interpeduncular fossa, near or in the sulcus of the oculomotor nerve. It passes laterally along or under the superior border of the pons, loses some of its fibres in the lateral sulcus of the mesencephalon, then runs inferiorly between the superior cerebellar peduncle and the brachium of the pons to disappear in the junction of these. Being sometimes double, it is known as the lateral filaments of the pons {fila lateralia pontis or Icenia pontis). The location of the cell-bodies giving origin to it is uncertain.
That portion of the rhombencephalon overlying the pons and forming the floor of the fourth ventricle is not really a part of the pons at aU. It is merely a continuation of the brainstem from the meduOa below to the structures above. Therefore on the dorsal surface there is no line of demarcation between the pons and medulla below or between the pons and isthmus above. The fibres of the trigeminus and masticator nerve pass through the pontine fibres to and from their nuclei in the brain-stem.
3. THE CEREBELLUM
The cerebellum or hind brain is the largest portion of the rhombencephalon. It lies in the posterior or cerebellar fossa of the cranium, and dorsal to the pons and medulla oblongata, overhanging the latter. It fits under the occipital lobes of the cerebral hemispheres, from which it is separated by a strong dupUcation of the inner layer of the dura mater, the tentorium cerebelli.
Its greatest diameter Ues transversely, and its average weight, exclusive of the dura mater, is about 140 gm., or about 10 per cent, of the entire encephalon. It varies in development with the cerebrum, and, like it, averages larger in the male. It is relatively larger in adults than in children. Its development begins as a thickening of the anterior portion of the roof (dorsal zone) of the posterior of the three primary brain vesicles. Resting upon the brainstem, it roofs over the fourth ventricle and is connected with the structures anterior, below, and posterior to it by its three pairs of peduncles.
separated by narrow but relatively deep sulci. Unlike the spinal cord and medulla, in which the grey substance is centrally placed and surrounded by a mantle of white substance, the surface of the cerebellum is itself a cortex of grey substance, the cortical substance [substantia corticalis], enclosing a core of white substance, the medullary body [corpus medullare]. However, within this central core of white substance are situated definite grey masses, the nuclei of the ere bellum.
The gross divisions of the cerebellum are three: the two larger lateral portions, the hemispheres, and between these the smaller central portion, the vermis. The demarcation between these gross divisions is not very evident from the dorsal surface, because the hemispheres in their extraordinary development in man encroach upon the vermis, and, being pressed under the overlapping occipital ends of the cerebral hemispheres, they become partially fused upon the vermis
along the dorsal mid-line. Though differentiated simultaneously with the cerebellar hemispheres in the human fcetus, in most of the mammalia the vermis is the largest and most evident of the parts, and it is practically the only part which exists in the fishes, reptiles, and birds. In man, owing to the fact that the vermis does not keep pace in development with the hemispheres, there results a very decided notch between the two hemispheres along the line of the entire ventral and inferior aspect of the cerebellum, the floor of this notch being the surface of the vermis. The inferior portion of the notch is the posterior cerebellar notch (incisura marsupialis) ; its prolongation above is wider than below, and is termed the superior cerebellar notch. It is occupied by a fold of the diu'a mater, the falx cerebelli. With the variations in contour of the cerebellum, certain of its sulci are broader and deeper, and merit the name fissures. These are more or less definitely placed, and subdivide the hemispheres into lobes'and the vermis (the median lobe) into lobules.
Superior surface. — The superior surface is bounded from the inferior sm-face by the horizontal fissure (fig. 635) which extends ventrolaterally, to the entrance of the brachium of the pons. Between this and the extreme anterior border of the dorsal surface are two other fissures, the posterior and anterior semilunar fissures. These, Hke the horizontal fissure, may be traced, with slight interruptions, across the mid-line, and consequently mark off not onl}^ the two hemispheres but also the vermis into corresponding divisions.
The superior semilunar lobe [lobulus semilunaris superior] (postero-superior lobe) of each hemisphere lies between the horizontal and the posterior semilunar fissm-es. It largely composes the outer border of the cerebellum, and, therefore, is the longest of the lobes.
The adjacent surface of the hemispheres, because of the frequently less complete development of the anterior semilunar fissure, is sometimes referred to as the quadrangular lobe, with its posterior and its anterior portions. On the other hand, especially when the anterior semilunar fissure is well marked, this area may be divided into — (1) the posterior semilunar lobe, between the posterior and anterior semilunar fissures, and (2) the anterior seynilunar lobe, anterior to the anterior semilunar fissure (fig. 635).
Anterior to the quadrangular lobe on each hemisphere is the ala of the central lobule, bounded by the postcentral and the precentral sulcus. Anterior to this, on the anterior margin of the hemisphere, is the vinculum lingulae, a slender process continuous with the lingula of the vermis (fig. 658).
The superior aspect of the vermis, the superior vermis, because of the fusion of the hemispheres, is, for the most part, a slight ridge, the monticulus (fig. 635), instead of a depression. However, in the posterior portion of the dorsal surfacethe depression of the posterior notch begins, and here the horizontal and the posterior semilunar fissures approach each other so closely that the corresponding subdivision of the vermis is seldom more than a single folium, the folium vermis (cacuminis) . >
The monticulus proper is divided into an inferior lobule, the declive, and a superior lobule, the culmen. These appear as continuations across the midline of the posterior and anterior semilunar lobes of the hemispheres, and are separated by the corresponding fissures (fig. 635).
At the extreme anterior part of the superior surface and in the bottom of the anterior cerebellar notch lies a more definitely defined portion of the vermis. This is the central lobule (fig. 635). It is broadened laterally into two pointed wings, the alee of the central lobule, the folia of which, if present, are parallel with those of the anterior semilunar lobes and separated from them by the postcentral sulcus.
{lingula vermis) will appear separated from the central lobule by the pre-central sulcus. It is a thin, tongue-like anterior projection of the cortical substance comprising four to eight folia adhering upon the anterior medullary velwm, the roof of the superior portion of the fourth ventricle.
Inferior surface. — ^The three cerebellar peduncles of each side join to form a single mass of white substance, and enter the ventral aspect of each hemisphere at the medial and ventral extremity of the horizontal fissure. The inferior surface of the cerebellum is less convex than the superior surface. The hemispheres are decidedly separated by a continuation of the posterior cerebellar notch, which becomes broader, the vallecula of the cerebellum, which contains the inferior portion of the vermis, vermis inferior, and whose margins embrace the medulla oblongata. The inferior surfaces of the hemispheres are each divided by the intervening fissures into four lobes (fig. 636).
Folium of vermis
Below, the inferior semilunar lobe (postero-inferior lobe) is separated from the superior semilunar lobe of the superior surface by the horizontal fissure. It is the largest of the inferior lobes, and is broader at its medial extremity. Frequently two and sometimes three of its curved sulci appear deeper than others, and separate it into two or three slender lobules [lobuli graciles]. More commonly there are two of these, the lobulus gracilis posterior and lobulus gracilis anterior, separated by the postero-inferior sulcus.
The biventral lobe is smaller and more curved than the inferior semilunar lobe, from the anterior margin of which it is separated by the curved antero -inferior sulcus. Its medial extremity is pointed and does not extend to the vermis; its lateral extremity is broader and curves anteriorly to the ventral extremity of the horizontal fissure — the line of outer termination of the inferior semilunar lobe.
The tonsil [tonsilla cerebelli] (amygdala) is a rounded, triangular mass, placed mesially within the inner curvature of the biventral lobe, and separated from it by the retrotonsillar fissure. Its inferior mesial border slightly overlaps the vermis.
The smallest of the lobes is the flocculus. It lies adjacent to the inferior and lateral surface of the mass of white substance produced by the confluence of the three cerebellar peduncles, and extends into the mesial extremity of the horizontal fissure. It is so flattened that its short folia give it the appearance suggesting its name. Occasionally there is added a second, less perfectly formed portion, the secondary flocculus. From each floccular lobe there passes toward the midline a thin band of white substance, the peduncle of the flocculus ; these extend
form the narrow posterior medullary velum.
The inferior vermis (figs. 634, 636) is more definitely demarcated than the superior. Lying in the floor of the vallecula cerebelli, it is separated on each side from the adjacent lobes of the hemispheres by a well-marked sulcus about it, the nidus avis. By contour and by deeper transverse fissures (sulci) occurring at intervals across it, four divisions or lobules of the inferior vermis are recognised. These lobules, like those of the superior vermis, are each in intimate relation with the pair of lobes of the hemispheres adjacent to it on either side.
1. The tuber vermis is adjacent to the folium vermis of the superior aspect, and thus is the most inferior lobule of the inferior vermis. It is a short, somewhat pyramidal-shaped division, whose four or five transversely arranged folia are continuous with the folia of the inferior semilunar lobes on either side.
2. The pyramid is separated from the tuber vermis by the post-pyramidal sulcus. Its several folia cross the vallecula cerebelli and curve to connect with the biventral lobes on either side.
3. The uvulva is separated from the pyramid by the prepyramidal sulcus. It is triangular in shape. Its base or broader inferior portion appears as two laterally projecting ridges of grey substance, the furrowed bands or alee uvulce, which extend across the floor of the nidus avis and under the mesial margins of the tonsils on either side. In these bands its folia curve and become continuous with the tonsils. The uvula and the two tonsils are sometimes referred to collectively as the uvular lobe.
4. The nodule is the smallest and most anterior division of the inferior vermis. It is separated from the uvula by the post-nodular sulcus, and is closely associated anteriorly with the posterior medullary velum, the transverse continuation of the peduncles of the floccular lobes.
Internal structure of the cerebellum (fig. 637). — The white substance of the cerebellum is continuous with its peduncles and forms a compact central mass. Over the surface of this the grey substance or cortex is spread in a thin but uniform and much folded layer. Upon section of the cerebellum certain of the sulci as well as the fissures are shown to be much deeper than is apparent from the surface. The deeper sulci separate the lobes into divisions, the medullary laminae, each of which is composed of a number of folia and each of which has its own core of white substance. The folia of the laminae line the sulci (and fissures), and also comprise their surface aspect, and are separated by the shallow, secondary sulci. The larger
laminae are subdivided into from two to four secondary laminae of varying size. Such subdivision is especially marked in the vermis. Here each lamina comprises a lobule and is, therefore, separated by a fissure, and each lobule is usually subdivided with the exception of the nodule, the folium, and the lingula. In sagittal sections, or sections transverse to the general direction of the sulci, this arrangement of the laminae gives a foliate appearance, which, especially in sagittal sections of the vermis, is termed the arbor vitae (see fig. 634).
The outermost or molecular layer contains small stellate cells, "basket cells," with relatively long dendrites. These serve to associate the different portions of a given fohum. The axones of the largest of them give off branches which form pericellular baskets about the bodies of the cells of Purkinje, each axone contributing to several baskets. The layer of Purkinje cells, or the middle layer, is quite thin. The bodies of the cells of Purkinje are arranged in a single layer, and their elaborate systems of dendrites extend throughout and largely compose the molecular layer. The dendrites of these, the most essential cells of the cortex, are displayed in the form of arborescent fans (see fig. 604), arranged parallel with each other and transverse
Fig. 636. — Diagram of the Inperioe Surface op the Cerebellum after the Removal OF the Medulla Oblongata, Pons, and Mesencephalon. The tonsil of the right side is omitted in order to display the connection of the pyramid with the biventral lobe, the furrowed band of the uvula, and more fuUy the posterior meduUary velum. The anterior notch is less evident than in the actual specimen.
Posterior cerebellar notch
to the long axis of the folium containing them. Their axones are given off from the base of the ceU-body and acquire their medullary sheaths quite close to the ceU-body, and, after giving off several collaterals in the inner layer, pass into the general white substance and thence to other laminae or lobes. Certain of them go to structures outside the cerebellum. The inner layer is the granular layer. It contains numerous small nerve-cells or " granule-ceUs " which possess from two to five radiating dendrites, unbranched except at their termination, which occurs suddenly in the form of three to six claw-hke twigs. Thek axones are given off either from the ceU-body direct or more often from the base of one of the dendrites, and pass outward into the molecular layer, where they bifurcate and course in both directions parallel to the long axis of the folium, to become associated with the dendrites of the cells of Purkinje. In the layer of the cells of Purkinje there is situated at intervals a neurone of the Golgi type II (see fig. 604). The short, elaborately branched a.xone of this neurone is distributed among the cells of the granular layer. Axones conveying impulses to the cerebellar cortex terminate in the granular layer as 'moss fibres,' or directly upon the cells of Purkinje as 'climbing fibres,' and probably upon the cells of the Golgi type II.
Thus the neurones which receive impulses coming to the cortex are the cells of Purkinje, probably the Golgi cells of type II, and the granule-cells; those which distribute these impulses to other neurones of the folium are the Golgi cells of type II, the granule-ceUs, and the basketcells (association neurones), and the collaterals of the cells of Purkinje. Impulses are conveyed from the cortex of a folium to that of other folia, lamina, lobules or lobes, or to the nuclei of the cerebellum, or to structures outside the cerebellum by the axones of the cells of Purkinje.
The nuclei of the cerebellum (fig. 637) are in its central core of white substance. They are four in number, and all are paired, those of each pair being situated opposite each other on either side of the mid-line.
1. The largest of them is the dentate nucleus. This is an isolated mass of grey substance situated in the core of white substance of each hemisphere. It is in the form of a folded or corrugated cup-shaped lamina, with the opening of the cup (hilus) directed anteriorly and obliquely toward the mid-line. It contains a mass of white substance and possesses a capsule. Its cell-bodies give rise to most of the fibres forming the superior cerebellar peduncles.
2. The nucleus emboliformis is an oblong and much smaller mass of grey substance, which lies immediately medial to the hilus of the dentate nucleus. It is probably of the same significance as the dentate nucleus, being merely a portion separated from it.
3. The nucleus globosus, the smallest of the cerebellar nuclei, is an irregular horizontal mass of grey substance with its larger end placed in front. It lies close to the medial side of the nucleus emboliformis, and often appears separated into two or more rounded or globular masses.
nuclei, and is the most mesially placed. The pair is situated in the roof of the
Fig. 637. — Section op Cerebellum and Brain-stem Passing Obliquely Through Inferior Portion of Cerebellum to Superior Margin op Pons. (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
Interpeduncular fossa
fourth ventricle, and so near the mid-line that both nuclei are in the white substance of the vermis. They are ovoid in shape, and the nucleus of one side receives axones from the nucleus of the vestibular nerve chiefly of the opposite side, the decussation of these axones taking place in the vermis. Its cells are larger than those of the two first-mentioned nuclei.
The peduncles of the cerebellum. — The peduncles consist of three pairs — the inferior, middle, and superior. The three peduncles of each side come together at the level of the lower border of the pons, and the entering and emerging fibres of which they are composed become continuous with the central core of white substance of the cerebellar hemispheres. (Fig. 631, 638, 639.)
The restiform body of the medulla oblongata is the inferior peduncle. It forms the lateral boundary of the inferior portion of the fourth ventricle, and upon reaching the level of the pons turns sharply backward into the cerebellum. In the region of the turn it is encircled externally by fibres of the cochlear nerve. It contains fibres, both ascending and descending, between the cerebellar cortex and the structures below the cerebellum.
Its fibres include: (1) fibres from the spinal cord including the dorsal spino-cerebellar fasciculus (direct cerebellar tract) and probably a small proportion of the ascending fibres of the superficial ventro-lateral spino-cerebeUar fasciculus (Cowers' tract); (2) fibres from the
PEDUNCLES OF THE CEREBELLUM
olive of the same and opposite side of the medulla oblongata; (3) fibres from the nuclei of the funiculus gracilis and cuneatus of the same and opposite sides; (4) fibres to and from the olive of the opposite side; (5) fibres to the nuclei of the motor cranial nerves; (6) fibres descending to the ventral horn cells of the spinal cord. The ascending or afferent fibres of the spino-cerebellar and cerebeUo-olivary fasciculi are the principal components of the inferior peduncle; the existence of fibres (5) and (6) is not weU estabhshed. Of these, the fibres of the direct cerebellar tract terminate in the cortex of the superior vermis of both sides of the mid-hne, but, for the most part, in that of the same side. The olivary fibres end in the cortex of both the superior vermis and the adjacent cortex of the hemispheres, and some of them terminate in the nucleus dentatus.
The brachium pontis'or the middle peduncle is the largest of the three cerebellar peduncles. In it the pons fibres pass slightly downward and into the cerebellar hemisphere, between the lips of the anterior part of the horizontal fissure, entering lateral to the inferior peduncle.
It consists of the transverse fibres of the pons, and within the cerebellum its fibres are distributed in two main groups — the upper transverse fibres of the pons apparently pass downward to radiate in the lower portion of the hemisphere, whUe the lower transverse fibres pass upward and medialward to radiate in the superior part of the hemisphere and vermis. For the most part the fibres of the middle peduncle may be considered as commissural fibres, passing from one side of the cerebellum to the other. Each peduncle contains fibres coursing in opposite directions. Many of these fibres are interrupted in their course to the opposite side by cells scattered throughout the pons, nuclei of the pons, and, therefore, in each brachium pontis some of the fibres are processes of the cells of the cerebellum and course toward the opposite side, while others are processes of the cells of the pontine nuclei and course to the cerebellar hemisphere of the same side. Many cell-bodies of the nuclei of the pons whose axones terminate in the cerebellum receive impulses from fibres descending from the cerebral cortex of the opposite side — coriico-pontine fibres. Furthermore, there are evidences after degeneration that the brachium pontis also contains a few fibres from the cerebellum to the structures of the brainstem and spinal cord.
The brachium conjunctivum or superior cerebellar peduncle emerges from the cerebellum on the medial side of the brachium pontis and also on the superior and medial side of the course of the restiform body. It forms the lateral boundary of the superior portion of the fourth ventricle and is the cerebello-cerebral peduncle. Its transverse sectioii appears semilunar in shape, with the concave side next to the cavity of the ventricle. The medial border, which inclines toward the mid-line, is connected with that of the corresponding peduncle of the opposite side by the anterior medullary velum, which thus roofs over the superior part of the fourth ventricle. The lateral border is distinguished from the pons by an open furrow or lateral sulcus.
The superior cerebellar peduncles are almost entirely efferent pathways as to the cerebellum and form the chief connections between the cerebellum and the cerebrum. They arise almost wholly from the dentate nuclei. As they course forward they slightly converge and disappear under the inferior quadrigeminate bodies. Here, in the tegmentum of the mesencephalon, they undergo an almost total decussation, and then the majority of the fibres of each peduncle, having thus crossed the mid-line, terminate in the red nucleus of the opposite side. The red, nucleus lies in the tegmentum of the mesencephalon, below the superior quadrigeminate bodies, and therefore quite close to the decussation. The cells of the red nucleus, about which the fibres of the peduncle terminate^ in their turn send processes (axones) into (1) the rubro-spinal tract of the spinal cord and (2) mto the prosencephalon, most of which latter terminate in the thalamus whose ceU-bodies give fibres to the cerebral cortex by way of the internal capsule; but some pass from the red nucleus under the thalamus to join the internal capsule.
In addition to the fibres having the origin and course described above, and which constitute the greater mass of the superior cerebellar peduncle, each peduncle is said to contain fibres which — (1) arise in the cerebellar cortex of the same and opposite sides of the mid-line, instead of from the dentate nucleus, and which join the peduncle at the side of the dentate nucleus, between it and the restiform body; (2) fibres which do not cross the mid-line in the decussation, but terminate in the red nucleus of the same side; (3) some fibres are not interrupted in the red nucleus, but pass directly into the thalamus; (4) a small proportion of fibres afferent as to the cerebellum, which arise in the structures of the cerebrum and pass in to the cerebellum; and (5) the greater part, if not all, of the ascending fibres of the superficial ventro-lateral spinocerebellar fasciculus (Gowers' tract) of the spinal cord. The latter, instead of entering the cerebellum by way of the restiform body, are deflected in the upper medulla and pass in the lateral tegmentum of the pons to the anterior medullary velum, where they turn backward to enter the cerebellum in its superior peduncle and pass to its cortex, probably from the lateral side of the dentate nucleus (see fig. 656).
The anatomy of the fourth ventricle. — The fourth ventricle is rhomboidal in shape, being considerably widened at the level of the brachia pontis and pointed at each end. Its floor consists of a slight depression in the brain-stem, the fossa rhomboidea, and corresponds to the floor of the central canal. Its pointed inferior end, the calamus scriptorius, is directly continuous with the central canal, and its narrowed superior end is continued into the aquseductus cerebri (Sylvii) of the mesencephalon, which is nothing more than a resumption of the tubular form of the canal.
The entire cavity of the ventricle is lined with an epithelium which is continuous with the epithehum, or ependyma, of the central canal below and the aqueduct above. The entire ventricle involves the isthmus of the rhombencephalon, the metencephalon and a portion of the medulla oblongata. It is divided for study into an inferior, an intermediate and a superior part.
The roof of the superior portion of the fourth ventricle is nervous, consisting of a thin lamina of white substance, the anterior (superior) inedullary velum, thickened at the sides by the brachia conjunctiva. At its extreme mesencephalic end (in the isthmus of the rhombencephalon) the anterior medullary velum is slightly thickened by a continuation of the white substance of the inferior quadrigeminate bodies, forming the frenulum veil. The inferior portion of the velum is continuous with the white substance of the cerebellum, and is covered by the lingula cerebelli, an extension of the cortical substance of the superior vermis (fig. 631).
The roof of the intermediate portion of the fourth ventricle is formed by the cerebellum proper, the vermis and the mesial portions of the hemispheres. The nervous portion of the roof terminates with the posterior (inferior) medullary velum, a thin, narrow band of white substance which is the continuation of the peduncles of the fioccular lobes, and which connects them at the mid-line with the nodule of the inferior vermis.
The roof of the inferior portion of the fourth ventricle is non-nervous. It is the chorioid tela of the fourth ventricle, a semilunar lamina consisting of the epithelial lining of the ventricle, reinforced by a continuation of the connective tissue of the pia mater and the adjacent portion of the arachnoid. Along the line of its
THE FOURTH VENTRICLE
attachment to the surface of the medulla it is thickened, and in sections this portion bears the name ligula {toRiiia ventriculi quarti). The thickest portion spans the tip of the calamus scriptorius and is termed the obex. The width of the ventricular cavity is extended laterally from its widest part into the lateral recesses. narrow pockets on each side and around the upper parts of the restiform bodies. In the mid-Hne of the lower part of the chorioid tela there is a more or less wellmarked opening, the foramen of Magendie (medial aperture of the fourth ventricle), which is a lymph-channel connecting the cavity of the ventricle with the subarachnoid space. There is a similar opening from each lateral recess {lateral apertures of Key and Retzius).
The chorioid plexuses of the fourth ventricle consist of highly vascular, lobular, villus-like processes of the ventricular lining (and pia-mater) of the chorioid tela. They are reddish in the fresh specimen, and the epithelial lining of the ventricle is closely adapted to the unevennesses of their surfaces. From below they run as
Foramen of Magendie
two parallel masses on either side of the mid-line, which become united above, and then are separated again into two lateral processes which bend at right angles and project into the lateral recesses. Portions frequently protrude through the three openings of the ventricle into the subarachnoid space.
The floor of the fourth ventricle [fossa rhomboidea] (fig. 640). — This is thrown into eminences and depressions indicative of the internal structures of the brain-stem subjacent to it. Its inferior portion is the dorsal surface of the upper portion of the medulla oblongata; its intermediate portion is the dorsal surface of the pons region, while its superior portion belongs to the isthmus of the rhombencephalon. Its triangular lower e.xtremity terminates as the opening of the central canal of the spinal cord. This portion is deepened at the obex and shows furrows which point downward and converge medialward, giving the appearance known as the calamus scriptorius. The mid-line of the floor is sharply distinguished by the well-marked median sulcus, which becomes shallower above than below. In the tip of the calamus scriptorius, immediately anterior to the obex, the median sulcus deepens to become continuous into the central canal. This terminal depression is known as the ventricle of Arantius. Throughout the length of the floor on either side of the median sulcus is a continuous ridge, the medial eminence, which is bounded laterally by the limiting sulcus. Underlying the floor of the ventricle is a layer of grey substance of varying thickness, which is continuous with that surrounding the central canal of the cord. The medial eminence is subdivided into portions of unequal width and elevation, and the limiting sulcus accordingly shows fovesE of different depths.
The area postrema of Retzius is a superficial vascular structure bounded inferiorly by the tEenia and overlying the terminal portion of the nucleus of the fasciculus gracilis (clava) and a portion of the nucleus of termination of the vagus nerve. The funiculus separans, a short oblique fold of the floor, composed chiefly of neurogUa, separates the area postrema from the ala cinerea (irigonum vagi), which is an oblique, grey-coloured, wing-shaped eminence indicating the middle third of the nucleus of termination (recipient nucleus) of the vagus and glossopharyngeal nerves. At the superior extremity of the ala cinerea is a well-marked triangular depression of the limiting sulcus known as the inferior fovea. Mesial to and extending above the ala cinerea is a narrow triangular eminence lying close to the median sulcus, which represents the nucleus of origin of the hypoglossal nerve, the hypoglossal eminence [trigonum n. hypoglossi]. The lateral field of this eminence shows small oblique rugse, giving it a "feathery" appearance, the area plumiformis of Retzius. The nucleus intercalatus of Van Gehuchten is a wedgeshaped portion very slightly demarcated from the hypoglossal eminence, and intercalated between it and the inferior fovea. This nucleus is considered by some observers as an inferior
medial extension of the nucleus of termination of the vestibular nerve (area acustica), but Streeter, who has made a detailed study of the floor of the fourth ventricle by means of serial sections, doubts that it is a part of this nucleus. It is much more probable that it supplies visceral efferent flbres to the vagus and is thus a continuation of the dorsal efferent nucleus of the vagus.
Superior to the inferior fovea, and crossing each half of the floor of the fourth ventricle, are the acoustic striae. These are bundles of axones arising in the dorsal nuclei of termination of the cochlear or auditory nerve, which are situated in the lateral periphery of each restiform body. The bundles course around the dorsal periphery of the upper portion of the restiform body, then across each half of the floor of the ventricle to the median sulcus, in which they suddenly turn ventrally into the substance of the medulla oblongata, and in doing so they cross the mid-line to enter the substance of the opposite side. The striie vary greatly in different individuals, both in the degree of their prominence and their direction. Sometimes no striae are visible from the surface. Frequently a bundle may be discerned which courses obliquely upward and lateralward from the median sulcus to disappear in the floor further away from the mid-Une and again, a bundle may depart from the transverse course before reaching the median sulcus. Such a bundle ascending is sometimes called conductor sonorus. The acoustic striae cross the acoustic area. This is the flattened elevation which occupies the whole lateral portion of the intermediate portion of the floor of the ventricle, lateral to the limiting sulcus, and extends into the inferior portion lateral to the inferior fovea. It represents the subjacent
STRUCTURE OF MEDULLA OBLONGATA 815
nucleus of termination of the vestibular nerve. The dorsal and ventral nuclei of the cochlear nerve {iuberculum acusticum) are indicated by the ventro-lateral fullness in the contour of the restiform body. In many of the mammals they produce a well-marked protuberance.
In its superior portion the medial eminence occupies the greater part of the floor of the fourth ventricle, and in the upper part of the intermediate portion of the floor it presents a broader, well-marked, elongated elevation, the eminence of the facial and abducens or the colliculus facialis. This represents the mesiaOy placed nucleus of origin of the abducens and the genu of the root of the facial nerve, which root courses around and above the nucleus of the abducens. The nucleus of the facial is too deeply situated to produce an eminence. Lateral to this eminence is a depression of the limiting sulcus, which overUes the mesial part of the region of the larger portion of the nucleus of termination of the trigeminus, and is the fovea trigemini or superior fovea. The strip of the floor above the superior fovea and lateral to the medial eminence often appears greyish blue or dark brown, owing to pigmented cells subjacent to it, and is known as the locus caeruleus. It also represents a portion of the nucleus of the trigeminus. The most superior portion of the medial eminence becomes narrow and lies close to the mid-line. The function of the underlying grey substance producing it is uncertain, and for this reason Streeter has named the elevation nucleus incertus, noting that by position it is closely related to the upper portion of the nucleus of the trigeminus.
The finer detail of the internal structure lies within the scope of microscopic rather than of gross anatomy. However, the significance and relations of certain of the more important and larger of the internal structures of the meduUa and pons as observed in sections may be considered.
The entire brain-stem may be regarded as an upward continuation of the spinal cord, to which structures are added giving each part its peculiar character and conformation, and in which the structures characteristic of the spinal cord are modified in varying degrees.
The pyramids, the great descending or motor cerebro-spinal fasciculi, are directly continuous into the pyramidal fasciculi of the spinal cord. They form the extreme ventro-medial portion of the medulla, and from the fact that they contribute numerous fibres to the efferent nuclei (nuclei of origin) of the cranial nerves and to other portions of the grey substance of the brain-stem, they decrease appreciably in bulk in descending toward the spinal cord. Most of the fibres contributed to the medulla, as well as to other divisions of the brain-stem, decussate as they leave the pyramids, and terminate in the grey substance of the opposite side. However, the chief decussation of the pyramids occurs in the lower end of the medulla. Here usually about three-fourths of the fibres then comprising the pyramids cross the midline to form the lateral cerebro-spinal fasciculus (crossed pyramidal tract) of the spinal cord immediately below. The remaining fourth, comprising the more lateral fibres or those furthest away from the mid-line, continues uncrossed into the spinal cord as the ventral cerebro-spinal fasciculus or direct pyramidal tract. The majority of the latter fibres decussate gradually in the commissural bundle and in the ventral white commissure of the cord as they approach the levels of their termination. In practically all vertebrates except man and the apes there are no ventral pyramidal fasciculi, the decussation in the medulla being a total one. In man, the proportion of fibres crossing in the chief decussation varies. Cases have been noted in which apparently the entire pjTamids decussate at this level. In other cases the direct or ventral pyramidal tract may be much larger than usual, at the expense of the lateral. The decussation usuaUy appears to be symmetrical and it occurs so suddenly that the fibres, in coursing from the ventral to the lateral positions, detach the tips of the ventral horns of the spinal cord from the remainder of the grey figure, and these appear as isolated, irregularly shaped masses of grey substance in transverse sections of the medulla. From this level upward the outline of the grey figure of the cord is lost, and the cell-columns of the ventral horns occur in more or less detached groups as the motor nuclei of the cranial nerves.
The origin and decussation of the lemnisci (fillet) begins immediately above the decussation of the pyramids, and here the arrangements characteristic of the spinal cord are further modified. The dorsal portion of the grey figure of the cord is manifest up to this level, but here, after a considerable increase in its thickness, the grey commissure gives rise to two thick dorsal outgrowths on each side of the mid-hne. These dorsal projections of grey substance comprise the nuclei of termination (relays) of the chief ascending or sensory spino-cerebral fasciculi of the spinal cord. The nucleus of the fasciculus gracilis (nucleus of GoU's column) arises a little before the nucleus of the fasciculus cuneatus (nucleus of Burdach's column). The former extends slightly downward from its point of origin, so that its inferior extremity is included in sections through the decussation of the pyramids (fig. 6il). It produces a slight bulbous enlargement (the clava) of the end of the funiculus gracihs, while the nucleus of the fasciculus cuneatus corresponds to the cuneate tubercle of the external contour of the meduUa (figs. 632, 640). From the cells of these nuclei arise the lemniscus — the cephalic continuation of the spino-cerebral pathway which conveys the general bodily sensations to the cerebrum. In passing out of the nuclei the fibres of the lemniscus course in a ventro-medial direction. Curving around the region of the central canal, they contribute largely to the internal arcuate fibres, then, sweeping across the mid-line, they convert it into the raphe, and immediately after crossing (decussating) they turn cephalad and collect to form the bundle known as the lemniscus.
In the medulla, the lemnisci are two thin bands of fibres spread vertically on each side of the raphe, with their lower or ventral edges thicker than their dorsal edges. In their course toward the cerebrum they increase in bulk, owing chiefly to fibres being added to them from the nuclei of termination of the aiferent roots of the cranial nerves, which fibres likewise cross the mid-line as internal arcuate fibres to join the lemniscus of the opposite side. In passing
through the pons, the lemnisci gradually become spread horizontally, and beyond the pons their then more lateral portions are further displaced and come to course in the lateral borders of the isthmus rhombencephali and mesencephalon, while the medial portions remain nearer the mid-line. This lateral spreading of each lemniscus produces the lateral lemniscus and the medial lemniscus, distinguished in transverse sections of the superior pons and mesencephahc
The reticular formation of the medulla and pons region is considerably more abundant than in the spinal cord. As in the spinal cord, it consists of grey substance through which nerve-fibres, singly and in small bundles, course in all directions, and more sparsely than in other regions. In the medulla it is traversed by the internal arcuate fibres. It may be con-
sidered an enlarged continuation of the middle portion of the grey column of the cord, dispersed by numerous fibres, giving it the reticulated appearance which suggests its name. Its numerous nerve-cells belong, for the most part, to the association and commissural systems of the brain stem, and, therefore, the fibres arising in it correspond largely to the fasciculi proprii of the spinal cord. As in the cord, most of the fibres are of short course, serving to associate different portions of the same level and adjacent levels with each other. Those of long course show a tendency to collect into a small, well-marked bundle which courses one on each side close_ to the mid-line, ventral to the central canal in the closed part of the medulla, and near the median sulcus of the floor of the fourth ventricle, in the open part. In the mesencephalon this bundle is again situated closely ventral to the aquaeductus cerebri.
This bundle is known as the medial longitudinal fasciculus (posterior longitudinal bundle). It corresponds more nearly to the ventral fasciculus proprius of the spinal cord than to others of the fasciculi proprii. In the medulla it appears as the dorsal edge of the lemniscus, but in the shifting of the position of the lemniscus in the pons region, it retains its medial position and thus becomes isolated. By position it is especially adapted for the association of the nuclei of the cranial nerves. Evidence has been found that those fibres which arise in the corpora quadrigemina and descend the spinal cord in its sulco-marginal or ventral mesencephalo-spinal fasciculus, pass through the medulla in the medial longitudinal fasciculus. The nuclei of termination of the vestibular nerve are said also to contribute many fibres to it.
The inferior olivary nucleus is an added structui-e in the medulla oblongata, i. e., it has no homologue in the spinal cord. The two of them occupy the olivary prominences, the olives of the exterior, and constitute the most conspicuous and striking isolated masses of grey substance in sections of the medulla. They appear as crenated laminae of grey substance folded so as to encup a dense mass of white substance, and in actual shape the entire nucleus has the form of an irregular corrugated cup with the opening or hilus on the side toward the midline. The mass is so crumpled that the diameter of the hilus is appreciably less than the length of the nucleus, and thus transverse sections of either extremity of it appear as closed capsules.
Lemniscus Raphe
There are several small detached portions of the olivary nucleus known as the accessory olivary nuclei. These are named according to their position with reference to the chief portion or olive proper. They are plates less corrugated than the chief nucleus, and appear rod-like in sections. The largest is the dorsal accessory olivary nucleus. The medial accessory olivary nucleus is widest at its inferior end, which extends a little below the inferior extremity of the chief nucleus. The lateral accessory olivary nucleus is the smallest. In serial sections the accessory nuclei are found to be plates of grey substance usually continuous with one another.
The oUvary nuclei are mainly cerebellar connections. By both ascending and descending fibres each cerebellar hemisphere is connected with the olivary nucleus of the same and opposite sides. Serial sections of a human brain with congenital absence of one cerebellar hemisphere, described by Strong, show that the chief connection of a hemisphere is with the olive of the opposite side. These fibres necessarily pass between the cerebellum and the olives by way of the restiform body, and, in so doing, form an obliquely coursing bundle in the lateral border of the medulla known as the cerebello-olivary fibres (fig. 643). The olivary nuclei also comprise a secondary relay between the spinal cord and the cerebellum by way of the spino-olivary fasciculus of the cervical cord, and it will be noted that they receive fibres from the thalami. The latter fibres, the thalamo-olivary tract, approach the olive at its lateral periphery, while upward through the brain-stem the tract courses in a more medial position. This tract comprises one of the cerebro-cerebellar paths. Arising in the thalamus and terminating in the olive, its impulses reach the opposite cerebellar hemisphere by way of the cerebeUo-ohvary fibres.
or ventral to the inferior ohvary nucleus.
The internal arcuate fibres comprise fibres destined for both the cerebellum and cerebrum, and also for the association of the tegmental grey substance of the two sides in which they course. Certain of the fibres passing between one restiform body (cerebellar hemisphere) and the olive of the opposite side course internal to the olive of the same side, and thus form the ventral portion of the internal arcuate fibres. As noted above, the internal arcuate fibres consist in
greatest part of fibres being contributed to the lemnisci, arising from the cells of the nucleus of the fasciculus gracOis and fasciculus cuneatus and sweeping downward and decussating to form the lemniscus of the opposite side. However, all the fibres arising in these nuclei do not enter the lemniscus. A few of them cross the mid-line with the internal arcuates, but pass on to enter the restiform body (cerebellar hemisphere) of the opposite side. Some of these course ventraUy and, upon approaching the olive of the opposite side, are deflected around the ventral side of both the olive and the pyramid, and thus pass to the restiform body as external arcuate fibres also. Certain of the internal arcuate fibres arise from the cells of the nuclei of termination of the cranial nerves and from small cells situated in the grey substance of the reticular formation. These, in crossing the mid-line, correspond to the white commissures of the spinal cord. Some of them terminate in the meduUa; others, especially those from the nuclei of termination of the cranial nerves, join the lemniscus and pass toward the cerebrum; others reach the cerebellar hemisphere of the opposite side.
The external arcuate fibres, in addition to those mentioned above, comprise certain fibres which arise in the nuclei of the fasciculus gracilis and cuneatus and pursue a dorso-lateral course to enter the restiform body (cerebellar hemisphere) ol the same side. These form the dorsal segment of the external arcuates. The greater mass of the external arcuates are cerebellooHvary fibres. Certain of those passing from one olive to the restiform body of the opposite side are deflected at the raphe, and course on the ventral side of both the other olive and the pyramid in order to reach the opposite cerebeUo-ohvary bundle. Likewise, those passing from the restiform body to the opposite olive are deflected by the olive of the same side and pursue a similar course to the raphe. While out of the hilus of each olive streams a dense mass of white substance, yet many of the fibres concerned with the olive pierce its walls from all sides.
each pyramid, and, though it decreases inferiorly, it may be evident down to the decussation of the pjTamids. The nucleus receives its name from the fact that its larger portion is interpolated in the course of the external arcuates. It is continuous anteriorly with the grey substance or nuclei of the pons.
concerned, have no homologues in the spinal cord.
The central canal of the closed portion of the meduUa is surrounded by a greater amount of central grey substance, substantia grisea centralis, than is the canal in the spinal cord. This is largely gelatinous substance, the central gelatinous substance, and the nerve-fibres in coursing through the grey substance are partially deflected by it, leaving it as a cyhndrical, more evident area of grey substance than in other regions. In the open portion of the meduUa the central grey substance naturally forms a more transparent lamina just under the floor of the fourth ventricle. In the mesencephalon it again surrounds the reformed canal or aqueduct of the cerebrum.
The central connections of the cranial nerves are most easily homologised with spinal-cord structures. Functionally the cranial nerves are of three varieties:— (1) the motor or efferent nerves, comprising the oculomotor, the trochlear, masticator, the abducens, the facial, the spinal accessory, and the hypoglossus; (2) the sensory or afferent, comprising the olfactory, the optic, the trigeminus, the vestibular, and the cochlear and (3) the mixed, motor and sensory nerves, comprising the glosso-palatine, the glosso-pharyngeal, and the vagus. The nuclei of origin of the motor or efferent cranial nerves and the efferent portions of the mixed nerves are directly continuous with the cell columns of the ventral horns of the spinal cord, while the emerging root filaments and roots of these nerves correspond to the ventral roots of the spinal nerves. The nuclei of ter-
mination of the afferent or sensory cranial nerves and of the sensory portions of the mixed nerves correspond directly to the nuclei of the fasciculus gracilis and fasciculus cuneatus, and to the cell-bodies of association and commissural neurones of the medulla and cord and, functionally, are merely anterior continuations of these.
The nuclei of the efferent or motor cranial nerves lie in two parallel lines, one near the mid-line arid the other more laterally placed. The nuclei giving origin to the oculomotor, the trochlear, the abducens, and the hypoglossus are near the mid-line, and correspond to the ventro-medial and dorso-medial cell groups of the ventral horns of the spinal cord; the nuclei of origin of the masticator (motor
Ventral external arcuate fibres
root of the trigeminus) of the facial, and the nucleus ambiguus: giving origin to the motor portions of the glosso-pharyngeal and vagus nerves, together with the nucleus of the spinal accessory, correspond to the ventro-lateral and dorso-lateral cell-groups of the ventral horns of the spinal cord. The nerve-roots having medial nuclei of origin are those which make their exit from the brain-stem along tlie more media,l superficial line, while those having the more lateral nuclei comprise the more lateral hne of roots apparent on the surface of the stem. Some of the efferent fibres of the vagus, supposedly visceral efferent, arise from a small nucleus dorso-medial to the nucleus ambiguus, the dorsal efferent nucleus of the vagus. i he first two pau-s of cranial nerves, the olfactory and optic, are attached to the
prosencephalon. These are purely sensory, and make their entrance near the mid-line of the brain, both having superficially placed nuclei of termination. Of the other nerves, all having sensory or afferent functions enter the brain along the lateral or more dorsal line, and the ganglia giving origin to their afferent axones correspond directly to the spinal ganglia of the dorsal or afferent roots of the spinal nerves.
Commissural and associational neurones are much more numerous in the brain-stem than in the spinal cord. Their axones serve to connect the structures on the two sides of the mid-line and to associate the different levels of the same side. Just as in the spinal cord, those of longer com-se correspond to the fasciculi proprii. Many of their axones descend into the spinal cord.
Of the fifteen pairs of cranial nerves, eleven pairs are attached to the medulla oblongata and pons, viz., the trigeminus, the masticator, abducens, facial, glosso-palatine, vestibular, cochlear, glosso-pharyngeal, vagus, spinal accessory, and hypoglossus.
The hypoglossus, the motor nerve of the tongue, has its nucleus of origin beginning in the lower portion of the floor of the fourth ventricle at the level of the acustic striae. It ' is a long nucleus, lying close to the mid-line and just under the floor of the ventricle (hypoglossal eminence) and extending down to the region of the funiculus separans. Here it curves ventrally to a slight degree, and below the obex assumes a position ventro-lateral to the central canal, and thus extends a short distance below the level of the inferior tip of the olive. The nerve arises as a series of rootlets which traverse the entii-e thickness of the medulla (fig. 643), to emerge in line in the furrow between the olive and the pyramid and fuse to form the trunk of the nerve. The lowermost of the rootlets usually emerge below the ohve. The nucleus receives impulses — (1) from the cerebrum by way of divergent fibres from the pyramid of the opposite side (voluntary); (2) impulses brought in by the sensory fibres of the cranial nerves (reflex); and (3) by axones from other levels of the medulla (associational). None of its axones are supposed to decussate, though numerous commissural fibres are known to pass between the nuclei of the two sides.
The spinal accessory is likewise a purely motor nerve, and has a laterally placed, long, and much attenuated nucleus of origin. Above, its nucleus is in line with and practically continuous with the nucleus giving motor fibres to the vagus and glosso-pharyngeus (nucleus ambiguus). Below, it consists of the lateral and dorso-lateral groups of cells of the ventral horn of the first five or six segments of the spinal cord. The nerve arises as a series of rootlets which emerge laterally and join a common trunk, which passes upward between the dorsal and ventral roots of the upper cervical nerves and parallel with the meduOa to turn lateralward in company with the vagus. (See fig. 629). The upper rootlets arise from that part of the nucleus contiguous to the inferior end of the nucleus ambiguus, and are described as comprising the medullary or accessory part of the nerve; those which arise from the ventral horn cells below are described as the spinal part. The trunk of the spinal accessory fuses with the vagus in the region between its two ganglia, and, before separation, contributes fibres (the accessory part) to the trunk of the vagus. Some of the accessory fibres are distributed as motor fibres to the muscles of the larynx and some of them are visceral efferent fibres. The latter probably terminate chiefly in sympathetic ganglia which send axones to the heart. The spinal part is distributed to the sterno-mastoid and trapezius muscles. The nucleus of the spinal accessory receives terminal twigs of pyramidal fibres from the opposite side and is otherwise subjected to influences similar to those afi'ecting the cells giving origin to the motor roots of the spinal nerves.
The vagus or pneumogastric and the glosso-pharyngeus, though they have widely different peripheral distributions, are so similar in origin and central connections that they may be described together. Both contain efferent fibres, though both are in greater part sensory. They are similar as to the origin of both their efferent and afferent components. The afferent fibres of the vagus arise in its jugular gangUon and its nodosal ganghon (ganglion of the trunk); the afferent fibres of the glosso-pharyngeus arise in its superior ganghon and its petrosal ganghon. In both nerves these fibres enter the lateral aspect of the medulla and bifurcate into ascending and descending branches, similar to those of the dorsal root-fibres in the spinal cord. Some of these branches terminate in practically the same level of the medulla about cell-bodies situated on the same and the opposite sides. Such branches end chiefly in the nuclei of the hypoglossal and spinal accessorj^, and about the cells giving origin to the efferent components of the vagus and glosso-pharyngeus themselves — short reflex arcs. However, most of the afferent fibres terminate in the nucleus of termination of the vagus and glosso-pharyngeus: — (1) the nucleus of the ala cinerea, the middle portion of which is indicated in the floor of the fourth ventricle by the ala cinerea; (2) in the closed portion of the medulla, the lower end of the nucleus of the ala cinerea comes to lie in the dorso-lateral proximity of the central canal, and this portion is known as the commissural nucleus of the ala cinera (figs. 642 and 645) from the fact that fibres may be seen which pass directly from it across the mid-line; (3) the longer of the descending branches of the bifurcated fibres collect to form the solitary tract, a compact bundle situated dorsaUy just ventro-lateral to the nucleus of the ala cinerea and quite conspicuous in sections of the medulla. The fibres of this bundle terminate in the nucleus of the solitary trad, which is but a ventro-lateral and downward continuation of the nucleus of the ala cinerea enclosing the bundles forming the tract. It is most probable that the fibres of the solitary tract are chiefly from the vagus (pneumogastric), though Bruce has found evidence that the glosso-pharyngeal contributes to it appreciably. It decreases rapidly in descending the medulla, owing to the rapid termination of its fibres about the cells of its nucleus. It,
NUCLEI OF CRANIAL NERVES
with the axones given by the cells of its nucleus, is believed to extend as far downward as the level of the fourth cervical segment of the spinal cord. This being in the level of origin of the phrenic nerve, the tract forms a link in the respiratory apparatus which aids in the coordinated respiratory movements. The axones given off by the cells of the nucleus of the ala cinerea (terminal nuclei of the vagus and glosso-pharyngeus) course on both sides of the
mid-line, associating nuclei of other cranial nerves with vagus and glosso-pharyngeal impulses, many decussating to be distributed to the structures of the opposite side. Many join the lemniscus of the opposite side and pass into the cerebrum; others are distributed to the motor neurones of the cervical cord of the same and opposite sides (reflex axones), and no doubt others form central connections with the cells of the reticular formation of the medulla, though their precise relations have not been determined. ' '
Cell-bodies in the nucleus of the ala cinerea, the nucleus of the solitary tract and in the commissural nucleus of the ala cinerea comprise the so-called respiratory and vaso-motor nuclei ("centres") of the medulla. Some of the caudal branches of the axones given off by the cells of these nuclei descend the spinal cord, not only to the segments giving origin to the phrenic nerve, but also to those supplying the intercostal and levatores costarum muscles. Some of these augment the solitary tract; most of them descend in the reticular formation of the meduUa and cord. Further, axones given off by these cells convey vaso-motor impulses which are distributed to visceral efferent neurones throughout the cord.
of solitary tract
The nuclei of origin of the motor fibres of the vagus and glosso-pharyngeus are the dorsal efferent nucleus of the vagus and the nucleus ambiguus. The cells of the dorsal nucleus of the vagus lie somewhat clustered in the ventro-mesial side of the nucleus of the ala cinerea and lateral to the nucleus of the hypoglossus. Their axones pass outward among the entering or afferent vagus fibres, and it is suggested that most of them are visceral efferent fibres of the vagus, i. e., they terminate about sympathetic neurones. The nucleus ambiguus or ventral efferent nucleus of both nerves hes in the lateral half of the reticular formation, about mid-way between the olive and the line traversed by the rootlets of the two nerves. Its upper end is larger. Its cells are considerably dispersed by the fibres of the reticular formation. The axones arising from its cells course at first dorsalward and then turn abruptly outward to join
the rootlets of the vagus or glosso-pharyngeus, as the case may be. The vagus is thought to receive more efferent fibres from the nucleus ambiguus than does the glosso-pharyngeus, and Cunningham notes that it may be questioned whether the latter nerve contains any motor fibres at all, there being paths by which the fibres of its motor branch (to the stylo-pharyngeus muscle) might enter it other than direct from motor nuclei.
The oesiibtdar and cochlear nerves are usually considered as one nerve and together are designated as the acoustic or eighth cranial nerve. While both are purely sensory, are similar in development and course together, they are distinct as to function and their nuclei of termination differ. They are here described as separate cranial nerves. The two nerves approach the brain stem together and enter it at the lateral aspect of the junction of medulla oblongata and pons.
The vestibular nerve arises as the central processes of the bipolar cells of the vestibular ganglion, and passes into the brain-stem on the ventro-mesial side of the restiform body to find its nucleus of termination (nucleus vestibularis) in the floor of the fourth ventricle. This nucleus occupies a triangular area of considerable extent (area acustica, fig. 640), and is usually subdivided into a lateral nucleus (Deiters'), a medial 7iucleus (Schwalbe's), a superior nucleus (Bechterew's), and an inferior nucleus (nucleus spinaUs). The latter is a downward prolongation of the general nucleus vestibularis which accompanies the descending or spinal root of the nerve.
Nucleus arcuatas
From the cells of the lateral and inferior nuclei axones are given off which form paths to the lateral funiculus of the spinal cord (vestibulo-spinal fasciculus, fig. 619) and to its anterior marginal fasciculus (ventral vestibulo-spinal tract). From both the lateral nucleus and the superior nucleus a special path is given off which passes upward and terminates in the roof nucleus of the cerebellum (nucleus fastigii) of the opposite side and in the nucleus dentatus and the cortex of the vermis. Also, fibres arising in the nuclei fastigii are said to terminate in the lateral (Deiters') nucleus in addition to those which probably descend into the anterior marginal fasciculus of the spinal cord. From the medial and also from the superior nucleus fibres pass to the medial longitudinal fasciculus of both sides, and are distributed to the nucleus of the abducens of the same side and to the nuclei of the trochlear and oculomotor nerves of the opposite side and of the masticator nerve of the same and opposite sides. From the lateral and medial nuclei, and probably from aU, fibres arise which cross the midline to enter the lemniscus and ascend to the cerebrum (lateral portion of the thalamus) on the opposite side. The lateral (Deiters') nucleus is said to contribute more fibres to the medial longitudinal fasciculus than does a nucleus of any other cranial nerve. If any of these fibres descend the cord, they must do so in its anterior marginal fasciculus.
The inferior nucleus is accompanied by the descending or spinal root of the vestibular nerve, which begins to assemble in the nuclei above. This root is composed of both caudal branches of' the entering fibres of the nerve and chiefly of fibres arising from the cells of its nuclei. Thus for the vestibular nerve it corresponds in every way to the solitary tract for the vagus, and to the spinal tract of the trigeminus. Such of its fibres as descend into the spinal cord most probably do so in the lateral vestibulo-spinal fasciculus.
it is considered to be the nerve of equilibration, and the connections noted above may be considered the pathways by which it exercises this function. The fibres of the apparatus which are represented in the spinal cord are supposed to convey impulses to the ventral horn (motor) cells of the cord as far down as the lumbar region.
The cochlear nerve, the auditory nerve proper, arises as the central processes of the bipolar cells of the spiral ganglion of the cochlea. In the lateral periphery of the restiform body, just before the latter enters the cerebellum, the nerve finds its two nuclei of termination, the ventral nucleus and the dorsal nucleus (tuberculum acusticum, fig. 640).
From the dorsal nucleus arise the acoustic medullary strice. These bundles pass around the dorsal aspect of the restiform body and course just under the ependyma of the floor of the fourth ventricle to the mid-line, where they suddenly turn downward into the substance of the medullsa and in doing so, cross to the opposite side and join the lemniscus. As the lemniscus becomes separated higher up into a medial and lateral portion, these fibres course in the lateral lemniscul and are distributed chiefly to the grey substance of the inferior quadrigeminate and media,
Trapezoid body
geniculate body of that side. At the mid-line some of their fibres join the median longitudinal fasciculus and by way of it are distributed to the nuclei of origin of other cranial nerves. In frequent cases, the acoustic striae course so deeply beneath the ependyma as not to be superficially visible in the floor of the fourth ventricle.
From the ventral nucleus of termination fibres arise which terminate about the cells of the superior olivary nucleus of the same and opposite sides. The superior olive is a small accumulation of grey substance which lies in the level of the inferior portion of the pons, and in line with the much larger inferior ohvary nucleus of the medulla. However, it is not analogous to the latter in any sense. The two superior olives form links in the central acoustic chain. From cells of the superior ohvary nucleus of the same and opposite sides, fibres arise which pass by way of the lateral lemniscus and terminate in the grey substance of the inferior quadrigeminate body and in the medial geniculate body, thus associating these bodies with the ventral nucleus of cochlear termination of the opposite side. From the medial geniculate body fibres arise which pass to the cortex of the superior temporal gyrus. This path is supplemented by fibres arising in the inferior quadrigeminate body, which likewise go to the temporal lobe. In the lateral lemniscus some of the acoustic fibres are interrupted by cells of the nucleus of the lateral lemniscus. In crossing the mid-line, between the superior olives, the fibres from the two sources form a more or less compact bundle, the corpus trapezoideum (trapezium). To this are added fibres crossing between the nuclei trapeozidei, smaller masses of grey substance just ventral to the superior olives and probably of the same significance.
geniculate body is thought to be wholly a crossed one. Further, some fibres are described aa terminating in the superior quadrigeminale body of both the same and the opposite side. These, forming the stratum lemnisci of this body, are especially suggestive of associating auditory impulses with eye movements.
All the fibres arising in the superior ohvary nucleus do not enter the corpus trapezoideum and the lateral lemniscus. A small bundle, the peduncle of the superior olive, arises in each nucleus and courses dorsally to the region of the nucleus of the abducens. Here certain of its fibres terminate about the cells of the nucleus of the abducens, while others enter the medial longitudinal fasciculus and pass to the nuclei of the trochlear and oculomotor nerves, thus further establishing connections between auditory impulses and eye movements.
The facial nerve is commonly described as consisting of the "facial proper" and its so-called sensory root or pars intermedia, the two together being designated as the seventh cranial nerve. However, the pars intermedia neither serves as a sensory root for the facial nor is it purely sensory. Many years ago Sapolini considered it a separate nerve and later it was called the intermediate nerve of Wrisberg. More recent investigations of its development and distribution, especially those of Streeter and Sheldon, further indicate that it merits a separate description
and a separate name, and, indicative of its distribution, it is here described as the glosso-palatine nerve. The facial, the glosso-palatine and the abducens all have their nuclei within the level of the pons though the roots of all appear from under its inferior border.
The facial [nervus faciahs] has its nucleus (of origin) in the ventro-lateral region of the reticular formation, superior to and in line with the nucleus ambiguus. The axones given off by the cell-bodies of the nucleus collect into a bundle which, instead of passing ventrally and directly to the exterior of the pons, courses at first dorso-mesially to the mesial side of the nucleus of the abducens (ascending root of the facial) ; then it turns and courses superiorly for a few millimetres, parallel with the nucleus of the abducens and immediately beneath the floor of the fourth ventricle {genu internum); then it turns abruptly and pursues a ventro-lateral and inferior direction to its point of exit at the inferior border of the pons, just lateral to the olive and mesial to the entrance of the vestibular nerve. Its exit usually involves a few pons fibres. In transverse sections through the middle of the nucleus of the abducens the genu of the facial appears as a compact transversely cut bundle at the dorso-medial side of this nucleus.
The nucleus of the facial is described as consisting of two chief groups of cells, an anterior and a posterior group which give rise respectively to the axones of the superior and inferior branches of the facial nerve. It receives cortical impulses from the lower portion of the anteiior central gjTus of the cerebral cortex, from the root fibres of the trigeminus of the same side, which serves as its sensory root, and (chiefly) fibres arising from the nuclei of termination of the trigeminus. The nuclei of termination of the optic and the auditory nerves of the same and opposite sides give rise to fibres which terminate about its cells. The fibres from the cerebral cortex descend in the pyramidal fasciculi and cross by way of the raphe and arcuate fibres to terminate in the nucleus of the opposite side. The anterior group of the cells of the facial nucleus must receive cortical fibres not only from the cerebral hemisphere of the opposite but also from that of the same side, evidenced by the fact that the superior branch of the nerve is but little affected in facial paralysis resulting from a lesion in the cerebral cortex of one side. A lesion destroying the root of the nerve or its nucleus of origin will of course give total facial paralysis in the side of the lesion.
The glosso-palatine nerve {nervus intermedius, sensory root of facial, etc.) is a mixed nerve but largely sensory. It accompanies the facial from a short distance beyond the geniculum (genu externum) of the facial to its attachment to the brain stem. Its sensory fibres arise as T-fibres of the cells of the geniculate ganglion (at the geniculum of the facial) . The peripheral processes go aa the chorda tympani to supply the epitheUum of the anterior part of the tongue and that of the palate, especially of the palatine arches. The central processes enter the brain stem, bifurcate into caudal and cephahc branches, and find their nucleus of termination in a superior extension of the nucleus of the solitary tract (the ventral portion of the nucleus of the ala cinerea). The geniculate ganghon contains some ceU-bodies of sympathetic neurones, left over in it during the period of migration form its homologue of the ganglion crest.
The efferent fibres of the glosso-palatine arise from ceU-bodies lying dorso-medial to the nucleus of the facial and in the level between this and the nucleus of the masticator nerve superior to it. Its cells are usually scattered in the reticular formation in Mne with the dorsal efferent nucleus of the vagus. Since most of its fibres, at least, are concerned with sympathetic neurones (terminate in sympathetic gangha) and convey secretory impulses destined for the salivary glands, it has been called the nucleus salivatorius.
Medial stratum of pons
The abducens is a smaU, purely motor nerve, which suppUes the lateral rectus muscle of the eye. Its nucleus of origin Hes close to the mid-line in the medial eminence of the floor of the fourth ventricle, and in line with that of the hypoglossus. Its root-fibres, uncrossed, pursue a ventral course, inclining a Httle laterally and curving inferiorly to emerge from under the inferior border of the pons. They pass lateral to the pyramid, and often between some of its fascicuh. The nucleus receives cortical or voluntary impulses by way of the pyramidal fascicuU chiefly of the opposite side. Its connection with the auditory apparatus and the medial longitudinal fasciculus has already been noted. It probably receives afferent impulses through the fibres of the trigeminus as well as by fibres descending from the nuclei of termination of the optic nerve. It is also associated, by way of the medial longitudinal fasciculus, with the nucleus of the oculomotor nerve of the same and opposite sides.
The trigeminus is considerably larger than any of the nerves inferior to it, and has the most extensive central connections of any of the cranial nerves. It is a purely sensory nerve which enters through the brachium pontis in line with the facial nerve. It serves as the nerve of general sensibility for the face from the vertex of the scalp downward, and thus it corresponds to the afferent fibres (dorsal root) for all the nerves giving motor supply to structures underlying its domain. Its fibres arise from its large, trilobed, semilunar (Gasserian) ganglion, situated outside the brain. This corresponds to the dorsal root ganglion of a spinal nerve, and its cells give off the characteristic T-fibres with peripheral and central branches. The central or afferent branches upon entering the brain-stem bifurcate into ascending and descending divisions, just as the entering dorsal root-fibres of the spinal nerves, and find their nucleus of termination in a dorso-lateral column of grey substance, lying deeply and extending longitudinally through the brain stem, and consisting of the upward continuation of the gelatinous substance of Rolando of the spinal cord. Opposite the entrance of the nerve is a considerably thickened portion of this column of grey substance, known as the sensory nucleus of the trigeminus, and the remainder below is called the nucleus of the spinal tract (fig. 647). Both parts are equally "sensory." After bifurcation the branches of the entering fibres of the trigeminus terminate about the cells of these nuclei. The descending branches are much longer than the ascending,
and in passing downward form the spinal tract of the trigeminus, weU marked in aU transverse sections of the meduDa oblongata figs. 641, 642, 643, 649). The spinal tract decreases Snfdfv m descendmg the medulla, owing to the rapid termination of its fibr1L"n the nucleus ofthetmct^^
It has been traced as far down as the second cervical segment of the spinal cord. The ascending Pvt.n«i^n ^^^ f^'^l' T'* °^ *^^'^, terminate in the 'sensory nucleus,' and, therefore, the extension upward into the mesencephalon of the nucleus of termination of the trigeminus is both shorter and more scant than the spinal extension.
nuclei of the other motor cranial nerves, especially of the facial; (3) to the thalamus of the same and chiefly the opposite side, and thus, through interpolation of thalamic neurones, their impulses reach the somaisthetio area of the cerebral cortex. These fibres ascend in the recticular formation of the opposite side, most of them finally coursing strictly withia the medial lemniscus. In crossing the mid-line they contribute to the internal arcuates. (4) Some fibres of both the trigeminus direct and from its nucleus pass laterally into the cerebellum. The longer of the reflex or association axones arising in the nucleus of termination may contribute to the medial longitudinal fasciculus; many of them descend to terminate in the grey substance of the spinal cord below the levels in which the fibres of the spinal tract proper terminate. The nucleus of termination is directly homologous to the nuclei of the fasciculus graciUs and fasciculus cuneatus, and, like the nuclei of termination of all sensory cranial nerves, it contains cell-bodies homologous to those which give rise to the fasciculi proprii and commissural fibres of the spinal cord.
The masticator nerve [porlio minor n. irigemini] is a purely motor nerve, usually called the motor root of the trigeminus from the fact only that it makes its exit from the pons by the side of the entering fibres of the trigeminus, passes outward over the ventro-mesial side of the semilunar ganglion and accompanies the inferior maxiUary division (mandibular nerve) of the trigeminus till it divides totally into its branches for the motor supply of the muscles of mastication. It serves, therefore, as but a relatively small part of the "motor root" of the trigeminus.
The nucleus of origin of the masticator nerve is attenuated into two parts: (1) The chief nucleus (nucleus princeps) lies on the dorso-medial side of the larger portion (sensory nucleus) of the nucleus of termination of the trigeminus. It is the larger of the two parts and gives origin to much the greater part of the masticator. (2) Scattered anteriorly and continuous
with the chief nucleus, in line with the locus coci'uleus, are the cell-bodies usually described as the nucleus of the mesencephalic (descending) root. These cells lie in decreasing linear distribution, through the mesencephalon, as far anterior as the posterior commissure of the cerebrum, and the mesencephalic root of the nerve accumulates as it descends to join the exit of the fibres arising from the chief nucleus. The average diameter of its cells is somewhat less than for the chief nucleus.
It is not clearly settled that the fibres arising from the mesencephahc nucleus of the masticator nerve go to the muscles of mastication. As suggested by KoUiker, some of these may supply the tensor veli palatini and tensor tympani muscles. Recent investigations of lower animals by Johnston and Willems indicate that the mesencephalic root may contain no motor fibres at all, representing instead a portion of the sensory trigeminus fibres. It is claimed that some fibres in descendtug give off collaterals which terminate about cells in the chief nucleus, and thus an impulse descending by them is given a wider distribution and also reinforced by the interpolation of another neurone. Such fibres, however, maj' be the sensory fibres just mentioned terminating upon the cells of the nucleus to form simple reflex arcs.
Both parts of the nucleus of the masticator receive afferent impulses brought in by the trigeminus of the same (chiefly) and of the opposite side, and both receive cortical impulses by fibres from the inferior portion of the precentral gyrus which descend in the cerebral peduncles and cross to terminate in the nucleus of the opposite side.
of the pons, and their position and course have been described above. The pons proper (the bridge) consists of a mass of transversely running fibres continuous on either side into the brachia pontis or middle cerebellar peduncles. In the animal series the relative amount of these fibres varies with the size of the cerebellum upon which they are dependent. They are relatively more abundant in man than in other animals.
In transverse sections the pons fibres are seen to course ventrally about the main axis of the brain-stem, making it possible to divide the section into a basilar or ventral part and a dorsal part {tegmentum). The fibres in their transverse and ventral course around the medulla oblongata involve the pyramids. At the inferior border of the pons the fibres little more than separate the pyramids as such from the main axis of the brain-stem, but more superiorly the pons fibres pass through the pyramids, splitting them into the pyramidal fasciculi. These pyramidal or chief longitudinal fibres of the pons are the continuation of the basal portion of the cerebral peduncles through the pons, to emerge as the pyramids proper at its inferior border. They occupy an intermediate or central area among the pons fibres of either side, leaving the periphery of the pons uninvaded. The superficial pons fibres form the solid bundle of its ventral and lateral periphery and the deep pons fibres form similar bundles dorsaUy enclosing the area of pyramidal fasciculi (fig. 655).
In transverse sections through the inferior portion of the pons, the dorsal or tegmental part consists of structures continuous with and analogous to the structures of the meduUa oblongata immediately below, exclusive of the pyramids. In addition, this region contains the superior ohvary nucleus and the corpus trapezoideum. The significance of these structures and their relation to the nucleus of termination of the cochlear nerve is shown in figs. 650, 651 and 652. In this region the lemniscus (fillet) changes from the sagittal to the coronal plane, and its
lateral edges are becoming drawn outward and carry the lateral lemniscus of the regions superior to this. The medial longitudinal fasciculus, left alone by the change in the arrangement of the leminscus, maintains its dorsal position throughout the pons and into the mesencephalon above. The thalamo-olivary tract appears loosely collected in the dorsal part of the pons, dorso-medial to the nucleus of the superior olive.
The restiform body acquires in this inferior region a more dorso-lateral position than in the medulla below. Its fibres are beginning to turn upward in their course to the cerebellum mesial to the brachium pontis. Here the restiform body is nearing completion, and the fibres now contained in it may be summarised as foUows: —
vestibular and trigeminus, vestibular especially, and from the cells of the reticular formation.
(5) Descending fibres to the motor nuclei of the vagus and glosso-pharyngeal, and fibres descending into the anterior marginal fasciculus of the spinal cord, the latter, however, being in large part interrupted by cells in the nuclei of the vestibular nerve.
(6) A few fibres arising from the arcuate nuclei. These nuclei are continuous superiorly with the nuclei of the pons and some of their fibres are described as entering the cerebellum by way of the restiform body instead of by way of the brachium of the pons as in the levels above.
GREY SUBSTANCE OF THE PONS
ascends the medulla, dispersed in the reticular formation, and therefore in a more ventral position than that of the direct cerebellar tract. In this position it becomes enclosed by the fibres of the pons, and so it passes upward, beyond the pons, around the lateral lemniscus to the brachium conjunctivum, and there turns back to enter the cerebellum by way of its superior peduncle. Certain clinical phenomena, probably purely psychological, have been alleged to indicate that some of the fibres of Gowers' tract pass on to the cerebrum instead of turning in the medullary velum to enter the cerebellum.
The dorsal part of a transverse section through the upper part of the pons contains the superior cerebellar peduncles [brachia conjunctiva] instead of the restiform bodies or inferior peduncles. Instead of the cerebellum forming the roof of the fourth ventricle, in this region the roof is formed by the anterior medullary velum bridging the space between the two brachia conjunctiva. Adhering upon the meduUary velum is the lingula cerebelli — the superior and ventral extremity of the superior vermis. This is the only portion of the cerebellum attached to this region.
The lemniscus (fUlet) is found more lateral than at the inferior border of the pons, and is divided into the medial lemniscus and lateral lemniscus proper. The lateral lemniscus has shifted dorsally until in this region it courses in the dorso-lateral margin of the section external to the brachium conjunctivum. The mesencephalic root of the masticatornerve occurs in the dorso-
only cranial nerves represented here.
The transverse fibres of the ventral part of the section (pons proper), and therefore the brachia pontis, consist of fibres coursing in opposite directions. Many are fibres which are outgrowths of the Purkinje cells of the cortex of the cerebellar hemispheres, and pass either directly to the cerebellar hemisphere of the opposite side or turn dorsalward in the raphe to course longitudinally in the brain-stem both toward the spinal cord and toward the mesencephalon. Others terminate in the grey substance (nuclei) of the pons. Others are fibres which arise in the grey substance of the pons and pass to the cerebellar hemispheres, and still others are the cerebro-pontile fibres, from the temporal, occipital and frontal lobes.
The grey substance of the pons [nuclei pontis 1 occurs quite abundantly. At the inferior border of the pons it is found concentrated about the then more accumulated bundles of the emerging pyramids, and serial sections show it to be a direct upward continuation of the arcuate nuclei of the medulla oblongata below. Higher up it is dispersed throughout the central area in the interspaces between the transverse pontile and longitudinal pyramidal fasciculi. A large portion of the nerve-fibres passing through it are thought to iDe interrupted by its cells, which thus serve as links in some of the neurone chains represented by the fibres of the pons. Of the more important of such relations, the following are said to exist: —
(1) Fibres which arise in the cortex of one cerebellar hemisphere and terminate about cells of the nucleus pontis of the same and opposite side of the mid-line. These cells give off axones which pass to the other cerebellar hemisphere. In this relation the nuclei of the pons are analogous to the arcuate nuclei, save that the cerebellar fibres interrupted in the former are connected with the cerebellum by way of the brachia pontis instead of the restiform bodies.
(2) Certain of the descending oerebro-pontile fibres terminate about cells of the nuclei of the pons. Such cells give off fibres which probably, for the most part, pass to the cerebellar hemispheres, the impulses from the cerebral hemisphere of one side being conveyed to the opposite cerebellar hemisphere. Most of the descending cerebro-pontile fibres are thought to cross the mid-line to terminate about cells of the nuclei of the pons of the opposite side, a relation not sufficiently emphasised in the accompanying diagram (fig. 657).
Of the cerebro-pontile paths, the frontal pontile path (Ai-nold's bundle) is described as arising in the cortex of the frontal lobe (frontal operculum) passing in the anterior portion of the internal capsule down into the medial part of the base of the cerebral peduncle, and terminating in the grey substance of the pons. The descending temporal pontile path, sometimes caOed Turk's bundle, arises in the cortex of the temporal lobe, traverses the posterior portion of the internal capsule, lies lateral in the pyramidal portion of the cerebral peduncle, and terminates in the grey substance of the pons. In the posterior part of the internal capsule, the temporal pontile path is joined by a small bundle arising in the occipital lobe and going to the pons nuclei. This, supposedly smaller than the other two, adds an occipito-pontile path.
The total area in cross section of the pyramidal fasciculi as they enter the pons above is considerably greater than that which they possess as they emerge as the pyramids of the medulla below. The difference is considered very appreciably greater than can be explained as due to the loss of pyramidal fibres supplied to the nuclei of origin of the cranial nerves lying within the level of the pons, and the additional difference is explained as due to the termination within the pons of the oerebro-pontile paths.
THE ISTHMUS OF THE RHOMBENCEPHALON
The isthmus of the rhombencephalon is nothing more than the transition of the metencephalon into the mesencephalon above. It is quite short and comprised of only the structures which run through it, namely, the brachia conjunctiva (superior peduncles of the cerebellum), the anterior medullary velum, the lateral sulcus of the mesencephalon, the cerebral peduncles, and the inferior end of the interpeduncular fossa. It surrounds the superior extremity of the fourth ventricle. The lateral and medial lemnisci, the superior extension of the nucleus of the trigeminus, the mesencephalic nucleus and root of the masticator nerve and Gowers' tract extend through it. At the mid-line, just inferior to the inferior quadrigeminate bodies is the frenulum of the anterior medullary velum and the trochlear nerves, emerging at the sides of this, course ventrally around the sides of the isthmus. In the lateral sulcus, the isthmus shows usually a small triangular elevation known as the trigonum lemnisci from the fact that the lateral lemniscus tends toward the surface in this region.
Functions of the cerebellum. — From the above descriptions involving the structures of the metencephalon, it may be noted (1) that a given side of the cerebellum is associated chiefly with the same side of the general body and with the opposite side of the cerebrum. (2) That it receives afferent impulses from the spinal cord (brought into the cord by the dorsal roots of the spinal nerves) by way of the direct cerebellar fasciculus of the same side, and by Gowers' tract and from the nuclei of the fasciculus gracilis and cimeatus of the same and opposite sides. It further receives afferent impulses from the nuclei of termination of the trigeminus, glossopharyngeal and vagus of the same side chiefly, and especially does it receive afferent impulses from the nuclei of the vestibular nerve of the opposite and same side. (3) That the cerebellum sends impulses to the red nucleus, the thalamus and the cerebral cortex of the opposite side, and some of its fibres terminate in the nuclei of termination of the vestibular nerve and probably some fibres arising in its roof nuclei descend into the spinal cord direct. (4) That the cerebellum receives impulses from the thalamus of the opposite side by way of the thalamo-olivary tract and the inferior olive, and especially from the cerebral cortex of the opposite side by way of the frontal, temporal and occipital pontile paths and the nuclei of the pons. Further, fibres from the general pyramidal fascicuh are described as terminating about ceUs of the nuclei of the pons.
Taking into consideration these known associations of the cerebellum, the anatomically possible paths which in part may distribute cerebellar impulses to the grey substance sending efferent fibres to the peripheral tissues are (1) the general pyramidal fasciculi whose cortex of origin may receive impulses by fibroi proprioe from the cortical areas receiving impulses from the cerebellum. The pyramidal fasciculi, decussating, distribute impulses to the grey substance of i the medulla and cord of the same side as that from which the cerebeUo-cerebral impulses passed to the cortex. (2) The lateral vestibulo-spinal and the anterior marginal fasciculi to the ventral horn of the spinal cord of the same side, probably carrying impulses descending from the cerebellum as well as impulses brought in by the vestibular nerve and descending direct from its nuclei of termination into the spinal cord. (3) The rubro-spinal tract of the cord and probably some of the thalamo-spinal fibres (corpora-quadrigemina-thalamus path), the red nuclei and thalami being associated abundantly with the cerebellum. These tracts Hkewise decussate in descending but likewise do the cerebellar impulses ascending to their cells of origin.
Whatever other functions it may possess, developmental defects and pathologic lesions show that the cerebellum has to do with the equilibration of the body and the finer coordinations, adjustive control of the contractions of functionally correlated groups of muscles. Making this
THE MESENCEPHALON 833
possible, in part at least, it is seen above that is it associated (1) directly with the special nerve of equihbration, the vestibular; (2) with the optic apparatus by way of the thalamus, and (3) with the afferent impulses from the general body, by way of the direct cerebellar and Gowers' tracts, by way of the nuclei of the fasciculus gracilis and cuneatus, and the nuclei of termination of the trigeminus, glosso-pharyngeal and vagus. It has been suggested that by way of these latter paths the cerebellum deals especially with those general afferent impulses which arise within the muscles of the body (neuro-musoular spindles, etc.) and which are grouped under the name "muscular sense." The cerebellum can be considered as an enlarged and modified portion of the grey substance of the spinal cord, receiving a greater number and variety of afferent impulses and with them mediating more comprehensive and complicated reflex activities than is possible with the less abundant grey substance of a given portion of the cord proper.
The mesencephalon or mid-brain is that small portion of the encephalon which is situated between and connects the rhombencephalon below with the prosencephalon above. It is continuous with the isthmus rhombencephali, and occupies the tentorial notch, the aperture of the dm-a mater which connects the meningeal cavity containing the cerebellum with that occupied by the prosencephalon. Its greatest length is about 18 mm., and it is broader ventrally than dorsally. Its dorsal surface is hidden by the overlapping occipital lobes of the cerebral hemispheres. It consists of — (1) the lamina quadrigemina, a plate of mixed grey and white substance which goes over lateralward and below into (2), the cerebral
peduncles (crura) and their tegmental structures, and it contains (3), the nuclei of origin of the trochlear and oculomotor nerves. It arises from thickenings of the walls of the middle cerebral vesicle of the embryo, the lamina quadrigemina arising from the dorsal or alar lamina of this portion of the neural tube, while the basal lamina thickens to form the nuclei of the nerves, the substantia nigra, etc., and by the ingrowing of the cerebral peduncles. By means of the lamina quadrigemina roofing it over, the neural canal throughout the mesencephalon retains its tubular form and is known as the aquaeductus cerebri (Sylvii) , connecting the cavity of tlie fourth ventricle below with that of the third ventricle above.
External features. — Dorsal surface. — The lamina quadrigemina shows four well-rounded elevations, the quadrigeminate bodies [corpora quadrigemina], divided by a flat median groove crossed at right angles by a transverse groove. The anterior pair of these, the superior quadrigeminate bodies [colliculi], are
larger though less prominent than the inferior pair or inferior colliculi. Each colliculus is continued laterally and upward into its arm or brachium. The inferior brachium proceeds from the inferior colliculus, disappears beneath and is continuous into the medial geniculate body, and enters the thalamus. The superior brachium proceeds from the superior colliculus, disappears between the medial geniculate body and the overlapping pulvinar of the thalamus, and becomes continuous with the lateral geniculate body and thus with the lateral root of the optic tract.
The geniculate bodies are rounded elevations of grey substance which arise as detached portions of the thalami, and therefore belong to the thalamencephalon rather than to the mesencephalon. The superior quadrigeminate body or superior colliculus and the lateral geniculate body are a part of the optic apparatus, while the inferior colliculus and the medial geniculate body belong chiefly to the auditory apparatus (see Central Connections of Cochlear Nerve). Just as the terminal cochlear nuclei are connected by a few fibres with the superior colliculus, so do some fibres from the optic tract pass mto the inferior colliculus. Also some fibres form the optic tract (mesial root) are said to terminate in the medial geniculate body. Resting in the broadened medial groove between the superior quadrigeminate bodies lies the non-nervous epiphysis or pineal body. This also belongs to the thalamencephalon. Under the stem of the epiphysis is a strong transverse band of white substance crossing the
mid-line as a bridge over the opening of the cerebral aqueduct into the third ventricle. This is the posterior commissure of the cerebrum, and contains commissural fibres arising in both the thalamencephalon and mesencephalon. The triangular area bounded by the stem of the epiphysis, the thalamus, and the superior coUiculus with its brachium, is known as the habenular trigone.
Inferiorly, the lamina quadrigemina is continuous with the isthmus of the rhombencephalon by way of the brachia conjunctiva or superior cerebellar peduncles, and the anterior medullary velum which bridges between the mesial margins of these peduncles. The narrowed upper end of the velum, the part directly below the inferior quadrigeminate bodies, is thickened into a well-defined white band known as the frenulum veil. From the lateral margins of this band on each side and just below the inferior quadrigeminate bodies emerge the trochlear nerves (the fourth pair of cranial nerves), and the increased thickness of the band is largely due to the decussation of this pair of nerves taking place within it.
The brachium conjunctivum, together with the inferior and superior colliculi of each side, form a marked ridge which results in the lateral sulcus of the mesencephalon, a lateral depression between the base of this ridge and the cerebral peduncle below and continuous into the transverse sulcus at the superior border
of the pons. The ridge is thickened laterally by the lateral lemniscus, which is disposed as a band of white substance passing obhquely upward from under the brachium pontis, applied to the lateral surface of the brachium conjunctivum and which enters the lateral margin of the mesencephalon. The region at which the lateral lemniscus approaches nearest the surface and in which the largest portion of its nucleus lies is the slightly elevated trigone of the lemniscus.
The ventral surface of the mesencephalon is formed by the cerebral peduncles (crura), two large bundles of white substance which are close to one another at the superior margin of the pons, but immediately diverge somewhat, producing the interpeduncular fossa, and in so doing pass upward and lateralward to disappear beneath the optic tracts (fig. 629) . The posterior recess of the interpeduncular fossa extends slightly under the superior margin of the pons, while its anterior recess is occupied by the corpora mammillaria of the prosencephalon. The triangular floor of the fossa is the posterior perforated substance, a greyish area presenting numerous openings for the passage of blood-vessels. It is divided by a shallow median groove and is marked off from the medial surface of each peduncle by the oculomotor sulcus, out of which emerge the roots of the oculomotor nerves. The ventral surface of each peduncle is rounded and has a somewhat twisted appearance, indicating that its fibres curve from above medialward and downward. Sometimes two small, more or less transverse bands of fibres may be noted crossing the peduncle — an inferior, the tcenia pontis, and a superior, the transverse pedun-
cular tract. The inferior represents detached fibres of the pons; the superior, running from the brachium of the inferior quadrigeminate body and disappearing in the oculomotor sulcus, appears to be derived from the quadrigeminate bodies. Since it is well developed in the cat, dog, sheep, and rabbit, but is absent or little marked in the mole, it is supposed to be concerned with the optic apparatus.
Internal structure. — Transverse sections of the mesencephalon throughout are composed of — (1) a dorsal -part, consisting of the lamina quadrigemina or the grey sulDstance of the corpora quadrigemina, with the strata and bundles of nerve-fibres connected with them, and the abundant central grey .substance sm-rounding the aqueduct; (2) a tegmental part, consisting of the upward continuation of the reticular formation of the medulla oblongata and that of the
dorsal (tegmental) portion of the pons region, to which are added the superior cerebellar peduncles and the red nuclei of the tegmentum in which these peduncles terminate; (3) a paired ventral part, the cerebral peduncles, each of which consists of a thick, pigmented stratum of grey substance, the substantia nigra, spread upon the large, superficial, and somewhat crescentic tract of white substance known as the basis of the peduncle. The cerebral peduncles correspond to the longitudinal or pyramidal fasciculi of the pons and medulla. Likewise the lemniscus and the medial longitudinal fasciculus of the medulla and pons continue through all sections of the mesencephalon.
The central grey substance is a continuation of the central gelatinous substance of the spinal cord and the similar stratum of the medulla and that which immediately underlies the ependyma of the fourth ventricle. As in the spinal cord and medulla, it is largely composed of gelatinous substance. It is much more abundant in the mesencephalon, and in sections appears as a circumscribed area comparatively void of nerve-fibres.
of nerve-cells which give origin to its fibres. It courses caudalward close to the lateral margin of the central grey substance, and is quite small at its beginning in the extreme superior part of the mesencephalon, but as it descends toward the exit of its fibres from the pons, it increases slightly in size, due to the progressive addition of fibres. Its nucleus also increases sUghtly in bulk in approaching the region of the chief motor nucleus of the nerve. As mentioned above, the investigations of Johnston and Willems in lower animals suggest that the cells of the mesencephalic nucleus may be sensory instead of motor in character. The sensory nucleus (nucleus of termination) of the trigeminus tapers rapidly and probably does not extend throughout the mesencephalon.
The nuclei of the trochlear and oculomotor nerves form a practically continuous column of nerve-cells extending close to the mid-line and ventral to the aqueduct of the cerebrum. They are in hne with the nuclei of origin of the abducens and hypoglossus, and, like them, may be regarded as an upward continuation of the ventral group of the cells of the ventral horn of the spinal cord. The portion of the column giving origin to the oculomotor nerve is considerably larger than that for the trochlear.
Fig. 661 . — Diagrams showing the Course op Origin of the Trochlear Nerves. (Stilling. The upper figure shows roughly the entire central course of the trochlear nerves; the lower represents their region of exit in transverse section.
Lateral lemniscus
A transverse section through the inferior quadrigeminate bodies involves a portion of the decussation of the brachia conjunctiva and the nuclei of origin of the trochlear nerves, while a transverse section through the superior quadrigeminate bodies passes through the red nuclei of the tegmentum and the nuclei of origin of the oculomotor nerves. The latter section will also involve the brachia of the inferior quadrigeminate bodies and the medial geniculate bodies connected with them, and, if slanting slightly forward it will involve the pulvinars of the thalami and the lateral geniculate bodies.
The trochlear or fourth nerve is the smallest of the cranial nerves, and is the only one which makes its exit from the dorsal surface of the brain, as well as the only one whose fibres undergo a total decussation.
Its nucleus of origin is situated beneath the inferior quadrigeminate bodies in the ventral margin of the central grey substance, quite close to the mid-line and to its fellow nucleus of the opposite side, and it is closely associated with the dorso-mesial margin of the medial longitudinal fasciculus. Its root-fibres pass lateralward and dorsalward, curving around the margin of the central grey substance, mesial to the mesencephalic root of the masticator nerve. As the root curves toward the mid-line in the dorsal region just beneath the inferior quadrigeminate bodies, it turns sharply and courses inferiorly to approach the surface in the superior portion of the anterior medullary velum, the frenulum veli. In this it meets and undergoes a total decussation with the root of its fellow nerve, and then emerges at the medial margin of the superior cerebellar peduncle of the opposite side. Having emerged, it then passes ventraUy around the cerebral peduncle, and thence pursues its course to the superior obhque muscle of the eye. It receives optic impulses from the superior quadrigeminate bodies and impulses from the cerebral cortex of chiefly the same side, and it is associated with the nuclei of other cranial nerves by way of the medial longitudinal fasciculus.
The oculomotor or third nerve, like the trochlear, is purely motor. It is the largest of the eye-muscle nerves. It supplies in all seven muscles of the optic apparatus: — two intrinsic, the sphincter iridis and the ciliary muscle, and five extrinsic. Of the latter, the levator palpebrse superioris is of the upper eyelid, while the remaining four, the superior, medial, and inferior recti and the obliquus inferior, are attached to the bulb of the eye. As is to be expected, its nucleus of origin is larger and much more complicated than that of the trochlear nerve.
Practically continuous with that of the trochlear below, the nucleus is 5 or 6 mm. in length and extends anteriorly a short distance beyond the bounds of the mesencephalon into the grey substance by the side of the third ventricle. It hes in the ventral part of the central grey substance, and is very intimately associated with the medial longitudinal fasciculus. Its thickest
Substantia nigra
portion is beneath the summit of the superior quadrigeminate body. The root-fibres leave the nucleus from its ventral side and collect into bundles which pass through the medial longitudinal fasciculus and course ventrally to the mesial portion of the substantia nigra, where they emerge in from six to fifteen rootlets which blend to form the trunk of the nerve in the oculomotor sulcus of the cerebral peduncles. Those bundles which arise from the more lateral portion of the nucleus course in a series of curves through and around the substance of the red nucleus below and, in the substantia nigra, join those which pursue the more direct course. The trunk thus assembled passes lateralward around the mesial border of the cerebral peduncle.
A portion of the fibres of the oculomotor nerve upon leaving the nucleus decussate in the tegmentum immediately below and pass into the nerve of the opposite side, in which they are beUeved to be distributed to the opposite medial rectus muscle. The ceUs of the nucleus have been variously grouped and subdivided with reference to the difTerent muscles supphed by the nerve. Perlia has divided them into eight cell-groups. The nucleus may be more easily considered as composed of an inferior and a superior medial group. The inferior group consists of a long lateral portion continuous with the nucleus of the trochlear nerve below, and a smaller medial portion, situated in the medial plane and continuous across the mid-line with its fellow of the opposite side. The superior medial group consists of cells of smaller size than the inferior, and is known as the nucleus of Edinger and Weslphal. It is believed to give origin to
supply the two intrinsic muscles concerned, viz., the ciliary muscle and the sphincter iridis.
The nucleus of the oculomotor is associated with the remainder of the optic apparatus — (1) by way of the neurones of the superior quadrigemtnate body with the optic tract (retina) and it receives impulses from the occipital part of the cerebral cortex of the same and the opposite sides, and probably from the motor cortex of the frontal lobe; (2) by way of the medial longitudinal fasciculus with the nuclei of the trochlear and abducens (the latter making possible the coordinate action of the lateral and medial recti for the conjugate eye movements produced by these muscles), and with the nucleus of the facial (associating the innervation of the levator palpebrifi with that of the orbicularis oculi); (3) with the nuclei of termination of the sensory nerves, especially the auditory, by way of the lateral lemniscus and medial longitudinal fasciculus. It is probably connected with the cerebellum by way of the brachia conjunctiva and red nuclei.
The eminence representing the inferior quadrigeminate body proper consists of an oval mass of grey substance, the nucleus of the inferior coUiculus, containing numerous nerve-cells, most of which are of small size. A thin superficial lamina of white substance, the stratum zonale, forms its outermost boundary, and fibres from the lateral lemniscus enter it laterally and from below {stratum lemnisci). Near the lateral margin of the central grey substance occurs the beginning of the inferior brachium, a bundle containing fibres to and from the medial geniculate body and the inferior quadrigeminate body.
The lemniscus in the mesencephalon is considered in two parts. The more lateral portion of the lemniscal plate occuring in the pons has here spread dorso-latorally, and occupies a position in the lateral margin of the section, and is known as the lateral lemniscus, while the medial portion which remains practically unchanged in the tegmentum is distinguished as the medial lemniscus. (See fig. 660). In the upper portion of the lateral lemniscus occurs a small, scattered mass of grey substance, the nucleus of the lateral lemniscus, in which manj' of its fibres are interrupted.
The upper and greater portion of the lateral lemniscus with its nucleus belongs to the auditory apparatus, being connected with the nucleus of termination of the cochlear nerve, chiefly of the opposite side. (See fig. 650.) A large part of the fibres of this portion terminate in the inferior quadrigeminate bodies. Many of the latter enter at once the nucleus of the body
(nucleus of inferior colliculus) of the same side, and disappear among its cells; others cross the mid-line to the quadrigeminate body of the opposite side. In crossing, some pass superficially and thus contribute to the stratum zonale, while others pass either through the nucleus or below it and cross beneath the floor of the mecUan groove between the stratum zonale and the dorsal surface of the central grey substance, forming there an evident decussation with similar fibres crossing from the opposite side. Most of the fibres arising from the cells of the nucleus of the inferior quadrigeminate body pass by way of the inferior brachium to the medial geniculate body and the thalamus; some pass ventrally to terminate in the nucleus of origin of the trochlear nerve and some pass forward and laterally to terminate in the cortex of the superior gyrus of the temporal lobe, the cortical area of hearing. Another portion of the lateral lemniscus passes obliquely forward in company with the inferior brachium, and terminates in the medial geniculate body. Thus a large portion of the lateral lemniscus, the inferior quadrigeminate bodies with their brachia and the medial geniculate bodies are concerned with the sense of hearing. The nucleus of the inferior quadrigeminate body receives fibres which arise in the cortex of the superior temporal gyrus of chiefly the same side.
Practically all the remainder of the lateral lemniscus terminates in the nucleus, or stratum cinereum, of the superior quadrigeminate body of the same and opposite sides. They approach the nucleus from below, and contribute to the well-marked band of fibres coursing on the dorsolateral margin of the central grey substance, and known as the 'optic-acoustic reflex path' or stratum lemnisci (fig. 662).
The medial lemniscus arises in the medulla oblongata from the nuclei (of termination) of the funiculus gracilis and funiculus cimeatus of the opposite side, and likewise from the nuclei of termination of the sensory roots of the cranial nerves of the opposite side. It is, therefore, a continuation of the central sensory pathway conveying the general bodily (including the head) sensations into the prosencephalon. CoursLag still more laterally than in the pons below, it passes into the hypothalamic grey substance, in the lateral portion of which most of its fibres terminate. By axones given off from the cells of the hypothalamic nucleus the impulses borne thither by the lemniscus are conveyed by way of the internal capsule and corona radiata to the gyri of the somsesthetic area of the cerebral cortex.
cephalon.
The principal components of each basis pedunculi are as follows: — (1) The pyramidal fibres, which occupy the middle portion of the peduncle and comprise three-fifths of its bulk, and which are outgrowths of the giant pyramidal cells of the somaesthetic area of the cerebral cortex, chiefly the anterior central gyi'us. These supply ' voluntary ' impulses to the motor nuclei of the cranial nerves on the opposite side, form the pyramids of the medulla, and are distributed to the ventral horn cells of the spinal cord of the opposite side. (2) The frontal pontile fibres, which course in the mesial part of the peduncle from the cortex of the frontal lobe to their termination in the grey substance of the pons. (3) The occipital and temporal pontile fibres. which run in the ventral and lateral portion of the peduncle from their origin in the occipital and temporal lobes to their termination in the grey substance of the pons.
The substantia nigra is continuous with the grey substance of the pons and that of the reticular formation below, and with that of the hypothalamic region above. Its remarkable abundance begins at the superior border of the pons, and it conforms to the crescentic inner contour of the cerebral peduncle, sending numerous processes which occupy the inter-fascicular spaces of the latter. It contains numerous deeply pigmented nerve-cells, which in the fresh specimen give the appearance suggesting its name.
Its anatomical significance is not well understood. It is known that some fibres of the medial lemniscus terminate about its ceUs instead of in the hypothalamus higher up, and Melius has found in the monkey that a large portion of the pyramidal fibres arising in the thumb area of the cerebral cortex are interrupted in the substantia nigra. It is probable that other fibres of the peduncle also terminate here.
The brachia conjunctiva or superior cerebellar peduncles, in passing from their origin in the dentate nuclei, lose their flattened form and enter the mesencephalon as rounded bundles. In the tegmentum, under the inferior colliculi, the two brachia come together and undergo a sudden and complete decussation. Through this decussation the fibres of the brachium of one side pass forward to terminate, most of them, in the red nucleus [nucleus ruber] of the tegmentum of the opposite side (fig. 589). Some fibres are said to pass the red nucleus and terminate in the ventrolateral part of the thalamus.
The red nuclei are two large, globular masses of nerve-cells situated in the tegmentum under the superior quadrigeminate bodies. At all levels they are considerably mixed with the entering bundles of the brachia conjunctiva, and they contain a pigment which in the fresh condition gives them a reddish colour, suggesting their name.
which pass — (1) into the thalamus and to the telencephalon (prosencephalic continuation of the cerebellar path), and (2) fibres which descend into the spinal cord, the 'rubro-spinal tract,' in the lateral funiculus (fig. 619). The latter cross from the red nucleus of the opposite side and descend in the tegmentum. The red nuclei are also in relation with the fasciculus relroflexus of Meynert, which belongs to the inter-brain.
The thalamo -olivary tract courses in the mesencephalon more dorsally than in the pons region. It runs in the ventro-lateral boundary of central grey substance just lateral to the nuclei of the trochlear and oculomotor nerves.
A small guadrigemino-pontile strand of fibres has been described as arising in the quadrigemina, especially the inferior pair, and terminating in the nuclei of the pons. Impulses carried by these fibres are probably destined for the cerebellar hemisphere of the opposite side.
enormously developed and in most of the mammals they are relatively larger and appear more complicated in structure than in man. They are concerned almost wholly with the visual apparatus, mediating most of the reflexes with which it is concerned.
The nucleus of the superior colliculus is of somewhat greater bulk than that of the inferior. It is capped by a strong stratum zonale (fig. 662), which has been described as composed chiefly of retinal fibres, passing to it from the optic tract by way of the superior brachium, but, since Cajal found in the rabbit that extirpation of the eye is followed by very slight degeneration of the stratum zonale, it is probable that it is composed of other than retinal fibres — possibly fibres from the occipital cortex and fibres arising within the nucleus itself. The nucleus is separated from the central grey substance by a weU-marked band of fibres, the stratum album profundum. This contains fibres from two sources: — (1) fibres from the lateral lemniscus which approach the nucleus from the under side, some to terminate within it, others to cross to the nucleus of the opposite side; (2) fibres which arise within the nucleus and course ventrally around the central grey substance, both to terminate in the nucleus of the oculomotor nerve and to join the medial longitudinal fasciculus and pass probably to the nuclei of the trochlear and abducens. The lemniscus fibres often course less deeply than (2) and give the stratum lemnisci. The optic fibres proper approach the nucleus by way of the superior brachium, and are dispersed directly among its cells; only a small proportion of them cross over to terminate in the nucleus of the opposite side. They consist of two varieties: — (1) retinal fibres which arise in the ganglion-cell layer of the retina and enter the superior brachium at its junction with the lateral root of the optic tract, and (2) fibres from the visual area of the occipital lobe of the cerebral hemisphere. Sometimes the optic fibres in their course within the nucleus of the superior coUiculus form a more or less evident stratum near the stratum album profundum. This is known as the stratum oplicum (stratum album medium). The portion of the nucleus between this stratum and the stratum zonale is called the stratum cinereum.
The fibres entering the nucleus from the lateral lemniscus probably all represent auditory connections. The stratum album profundum, composed of the lemniscus fibres and fibres from cells of the nucleus, and the stratum opticum together, form the so-caOed 'optic-acoustic reflex path' (fig. 662).
The mesencephalo-spinal amd the spine -mesencephalic (spino-tectal) paths course together ventro-lateral to the nuclei of the coUiculi. In the superior quadrigeminate bodies they course in the dorsal edge of the median lemniscus, between the stratum opticum and stratum album profundum.
From the various studies that have been made it appears that the superior coUiculus of the corpora quadrigemina is merely the central reflex organ concerned in the control of the eye muscles — eye muscle refle.xes which result from retinal and cochlear stimulation, and from some general body sensations by way of the spinal cord. Fibres from its nucleus to the visual area of the occipital cortex have been claimed for certain mammals, but in man the superior colliculus may be entirely destroyed without disturbance of the perception of light or color and flbres arising from its nucleus to terminate in the cerebral cortex are denied.
In the level of the anterior part of the superior colliculus the fibres which arise from the cells of its nucleus and course ventrally in the stratum album profundum ooUect into a strong bundle. This bundle passes ventral to the medial longitudinal fasciculus and, in the space between the two red nuclei, it forms a dense decussation with the similar bundle from the opposite side. In decussating the fibres turn in spray-like curves downward and soon join the medial longitudinal fasciculus. This is the 'fountain decussation' of Forel. It is said to be augmented by decussating fibres from the two red nuclei.
There is abundant evidence that fibres arising in the corpora quadrigemina descend into the spinal cord. Various studies make it appear that at least part of these are fibres from the fountain decussation, and that these course through the medulla oblongata in the ventral part of the medial longitudinal fasciculus, and thence descend into the cord in the 'quadrigeminothalamus path' (lateral mesencephalo-spinal tract) (fig. 619). The medial longitudinal fasciculus is continuous with the ventral fasciculus proprius of the spinal cord and most of these fibres arising in the superior quadrigeminate bodies retain their ventral position in the cord as the sulco-marginal fasciculus of the opposite side. Their termination about those ventral horn cells of the cervical cord which send fibres through the rami communicantes probably establishes the pathway by which the superior quadrigeminate bodies are connected with the cervical sympathetic ganglia, and by which may be explained the disturbances in pupillary contraction induced by lesions of the lower cervical cord.
The medial geniculate body and the medial root of the optic tract, which runs into the former, probably have nothing to do with the functions of the optic apparatus. Both remain intact after extirpation of the eyes. The medial root of the optic tract is apparently nothing more than the beginning of the inferior cerebral (Gudden's) commissure, a bundle passing by way of the optic tract, connecting the medial geniculate body of one side with that of the other side, and probably with the inferior colliculus.
The medial longitudinal fasciculus (posterior longitudinal fasciculus), continuous into the ventral fasciculus proprius and the sulco-marginal fasciculus of the spinal cord, extends throughout tlae rhombencephalon and mesencephalon, and is represented in the hypothalamic region of the prosencephalon. Deserted by the lemniscus at the inferior border of the pons, it maintains its closely medial position and courses throughout in the immediate ventral margin of the central grey substance of the medulla and floor of the fourth ventricle, and likewise in the ventral margin of the central grey substance of the mesencephalon.
The two fasciculi constitute the principal association pathways of the brain-stem, and, true to their nature as such, they are among the first of its pathways to acquire medullation. In the mesencephalon they become two of its most conspicuous tracts, and their course, in most intimate association with the nuclei of origin of the nerves supplying the eye muscles, suggests what is probably one of their most important functions, viz., that of associating these nuclei with each other and of bearing to them fibres from the nuclei of the other cranial nerves necessary for the co-ordinate action of the muscles of the optic apparatus associated with the functions of these other nerves.
Fibres from each medial longitudinal fasciculus terminate either by collaterals or terminal arborisations about the cells of the motor nuclei of aU the cranial nerves, and each nucleus probably contributes fibres to it. It also receives fibres from the nuclei of termination of the sensory nerves especially the vestibular. Thus it contains fibres coursing in both directions, and, while it is continually losing fibres by termination, it is being continually recruited and so maintains a practically uniform bulk. Thus, a given lesion never results iu its total degeneration. Many of the fibres coursing in it arise from the opposite side of the mid-line. A special contribution of fibres of this kind is received by way of the fovmtain decussation from the nucleus of the superior coUiculus of the opposite side. As noted above, it is in part continuous into the spinal cord as the ventral fasciculus proprius. It receives some fibres by way of the posterior commissure of the prosencephalon from a small nucleus common to it and the posterior commissure situated in the superior extension of the central grey substance of the mesencephalon. Van Gehuchten and Edinger describe for it a special nucleus of the medial longitudinal fasciculus situated beyond this commissure in the hypothalamic rsgion. This nucleus may be explained as an accumulation of the gray substance of the reticular formation below and as receiving impulses from the structures of the prosencephalon which are distributed by its axones to the structures below by way of the medial longitudinal fasciculus.
Scattered in the posterior part of the posterior perforated substance, near the superior border of the pons, is a small group of ceU-bodies forming the inter -peduncular nucleus (interpeduncular gangUon of von Gudden). Fibres arising in the habenular nucleus of the diencephalon curve posteriorly, forming the fasciculus retroflexus of Meynert, and terminate about its cells. Fibres arising from its cells course dorsalward and terminate about association neurones in the ventral periphery of the central grey substance. It is concerned with olfactory impulses.
14. Interpeduncular nucleus.
As frequently reaUzed in the above, the structures of the mesencephalon are both overlapped by, and are of necessity functionally continuous with, the structures of the next and most anterior division of the encephalon, the prosencephalon.
The prosencephalon or fore-brain includes those portions of the encephalon derived from the walls of the anterior of the three embryonic brain-vesicles. In its adult architecture it consists of — (1) the diencephalon (interbrain), comprising the thalamencephalon or the thalami and the structm-es derived from and immediately adjacent to them, and, in addition, the mammillary portion of the hypothalamic region; (2) the telencephalon (end -brain), comprising the optic portion of the hypothalamic region and the cerebral hemispheres proper. The last mentioned consist of the entire cerebral cortex or superficial mantle of grey substance, including the rhinencephalon, and also the basal ganglia or buried nuclei (corpus striatum), together with the tracts of white substance connecting and associating the different regions of the hemispheres with each other and with the structures of the other divisions of the central nervous system.
This comprises — (1) the mammillary bodies [corpora mammillaria] (albicantia) , the two rounded projections situated in the anterior part of the interpeduncular fossa, and (2) the anterior portion of the posterior perforated substance or the small triangle of grey substance forming the floor of the posterior part of the third ventricle, and which represents numerous openings for the passage of branches of the posterior cerebral arteries (fig. 668) . The hypothalamic portions of the cerebral peduncles might be included. The structures of the optic or remaining portion of the hypothalamus belong to the telencephalon.
cerebral meninges, the tela chorioidea of the third ventricle (velum interpositum). These removed (fig. 665), it is seen that the thalami on either side are by far the most conspicuous objects of the diencephalon. They, together with the parts developed in connection with them, are distinguished as the thalamencpehalon. The thalamencephalon consists of — (1) the thalami; (2) the metathalamus or geniculate bodies; and (3) the epithalanius, comprising the epiphysis with the posterior commissure below it and the habenular trigone on either side.
The thalami are two ovoid, couch-like masses of grey substance which form the lateral walls of the third ventricle. The cavity of the ventricle is narrow, and quite frequently the thalami are continuous through it across the mid-hne by a small but variable neck of grey substance, the massa intermedia ("middle commissure"). The upper surfaces of the thalami are free. The edges of the tela chorioidea of the third ventricle are attached to the lateral part of the surface of each thalamus, and, when removed, leave the taenia chorioidea lying in the chori-
oidal sulcus. Each thalamus is separated laterally from the caudate nucleus of the telencephalon, by a linear continuation of the white substance below, known as the stria terminalis thalami (taenia semicircularis). Like the quadrigemina, each thalamus is covered by a thin capsule of white substance, the stratum zonale. The average length of the thalamus is about 38 mm., and its width about 14 mm.; its inferior extremity is directed obliquely lateralward. The dorsal surface usually shows four eminences, indicating the position of the so-called nuclei of the thalamus within. These are the anterior nucleus or anterior tubercle, the medial nucleus or tubercle, the lateral nucleus, and the pulvinar, the tubercle of the posterior extremity. The pulvinar of the human brain is peculiar in the fact that it is so developed as to project inferiorly and slightly overhang the level of the quadrigeminate bodies. The projecting portion assumes relations with the optic tract and the metathalamus.
Tail of caudate nuclei
Both the structures of the metathalamus, the lateral and medial geniculate bodies, are connected with the optic tract, but it is thought that actual visual axones terminate only in the lateral genticulate body. As the optic tract curves around the cerebral peduncle it divides into two main roots. The lateral geniculate body receives a small portion of the fibres of the lateral root of the optic tract; the remainder pass under this body and enter the pulvinar of the thalamus. The medial geniculate body is connected with the medial root of the optic tract, which root consists largely, not of retinal fibres, as does the lateral root, but of the fibres forming Gudden's commissure (the inferior cerebral commissure). The retinal fibres contained in the medial root pass to terminate in the superior quadrigeminate bodies.
Of the epithalamus, the epiphysis (pineal body, conarium) is the most conspicuous external feature. This is an unpaired, cone-shaped structure, about 7 mm. long and 4 mm. broad, which also projects upon the mesencephalon so that its body rests in the groove between the superior quadrigeminate bodies. Its stem is attached in the mid-line at the posterior extremity of the third ventricle, and therefore just above the posterior commissure of the cerebrum (fig. 658). It is covered by pia mater, and is involved in a continuation of the tela chorioidea
of the third ventricle. Though it develops as a diverticulum of that portion of the anterior primary vesicle which gives origin to the thalamencephalon, it is wholly a non-nervous structure, other than the sympathetic fibres which enter it for the supply of its blood-vessels.
It consists of a dense capsule of fibrous tissue (pia mater) from which numerous septa pass inward, dividing tlie interior into a number of intercommunicating compartments filled with epithelial (ependymal) cells of the same origin as the ependyma lining the ventricles and aqueduct below. Among these cells are frequently found small accretions (brain-sand, acervulus cerebri), consisting of mixed phosphates of lime, magnesia, and ammonia and carbonates of lime. The compartments form a closed system. In function the epiphysis ranks as one of the glands of internal secretion of the body, and it is often referred to as the 'pineal gland.' However, it is perhaps funotionless in man.
lary body cinereum
Apparently arising from the base of the epiphysis, but having practically nothing to do with it, are the striae meduUares of the thalamus (striae pineales, pedunculi conarii, taenia thalami, habenulse) . These are two thin bands of white substance which extend from under the epiphysis anteriorly upon the thalamus, along the superior border of each lateral wall of the third ventricle, and thus form the boundaries between the superior and mesial surfaces of each thalamus.
They have been called the habenulce, from their relation to the habenular nucleus, situated in the mesial grey substance at their inferior ends. They are continuous across the mid-line in the habenular commissure, just below the neck of the epiphysis, and between it and the posterior cerebral commissure, or, rather the superior part of the latter (figs. 631, 665). It will be seen below that each habenula contains olfactory fibers from the fornix, the anterior perforated substance and the septum pellucidum, as well as fibres out of the thalamus, and that most of its fibres terminate in the habenular nucleus.
The ventro-lateral surface of the thalamencephalon is continuous into the hypothalamic tegmental region, the upward continuation of the tegmental grey substance of the mesencephalon. It is also adjacent to a portion of the internal capsule. Both these relationships, as well as the fibre connections of the diencephalon with the structures above and below it, are deferred until the discussion of the internal structure of the prosencephalon.
The mesial surface of the diencephalon (fig. 667), allows a better view of the shape and relations of the third ventricle. Below the line of the massa intermedia the ventricle is usually somewhat wider than it is along the upper margins of
the thalami. This greater width is occasioned by a groove in the ventromesial surface of each thalamus, known as the hjrpothalamic sulcus (sulcus of Monro). It is along the line of this sulcus that the third ventricle is continuous with the aqueduct of the cerebrum, and thus with the fourth ventricle below, and, likewise, with the two lateral ventricles of the cerebral hemispheres at its anterior end. The latter junction occurs through a small oblique aperture, the interventricular foramen (foramen of Monro), one into each lateral ventricle. The dorsal or upper portion of the third ventricle extends posteriorly beneath its chorioid tela
(velum interpositum) to form a small postfiiur n^ccss about the epiphysis. This is known as the supra-pineal recess. The anterior and ventral extremity of the third ventricle involves the pars optica hypothalami, which belongs to the telencephalon.
B. THE TELENCEPHALON. — External features. — The optic portion of the hypothalamus consists of that small central area of the basal surface of the telencephalon which includes and surrounds the optic chiasma, and comprises the structures of the floor of the anterior and ventral portion of the third ventricle. The area extends anteriorly from the mammillary bodies in the interpeduncular fossa, and includes the tuber cinereum and hypophysis behind the optic chiasma, and some of the anterior perforated substance in front of it.
The most anterior portion of the third ventricle is in the form of a ventral extension. The wall of this portion is almost wholly non-nervous and quite thin, and thus the cavity of the ventricle is but thinly separated from the exterior of
cerebrum is apparent.
The optic chiasma lies across and presses into the lower portion of the lamina terminalis, and in so doing produces an anterior recess in the cavity of the ventricle known as the optic recess. Behind the optic chiasma the floor of the third ventricle bulges slightly, giving the outward appearance known as the tuber cinereum, and the cavity bounded by this terminates in the infundibular recess.
The tuber cinereum then is a hollow, conical projection of the floor of the third ventricle, between the corpora mammillaria and the optic chiasma. Its wall is continuous anteriorly with the lamina terminalis and laterally with the anterior perforated substance.
The infundibulum is but the attenuated apex of the conical tuber cinereum, and forms the neck connecting it with the hypophysis. It is so drawn out that it is referred to as the stalk of the hypophysis. The cavity of the tuber cinereum (infundibular recess) is sometimes maintained throughout the greater part of the length of the infundibulum, giving it the form of a long-necked funnel. Near the hypophysis the cavity is always occluded.
Fig. 669. — Diagrams op the Hypophysis Cerebri. (After Testut.) A, posterior surface; B. transverse section; C, sagittal section; 1, anterior lobe; 2, posterior lobe; 3, infundibulum; 4, optic chiasma; 5, infundibular recess; 6, optic recess. In C the infundibulum is relatively much shorter than in the actual specimen.
The hypophysis cerebri (pituitary body or gland) is an ovoid mass terminating the infundibulum. It lies in the sella turcica of the sphenoid bone, where it is held down and roofed in by the diaphragma selloe, a spheroid pocket of the dura mater. It consists of two lobes, a large anterior lobe, the glandular or buccal lobe, and a smaller posterior or cerebral lobe. The posterior lobe is usually enclasped in a concavity of the anterior lobe.
Development. — The posterior or cerebral lobe alone is originally continuous with and a part of the infundibulum. It alone represents the termination of the hollow diverticulum which, in the embryo, grows downward from that part of the anterior cerebral vesicle which later becomes the third ventricle. The driginal cavity afterward becomes obliterated except in the upper part of the infundibulum. It is, therefore, of cerebral origin. The anterior or buccal lobe arises quite differently. It is developed from an upward tubular diverticulum (Rathke's pouch) of the primitive buccal cavity. In the higher vertebrates, including man, its connection with the buccal cavity becomes obliterated as the cartilaginous base of the cranium is consolidated, but in the myxinoid fishes the connection remains patent in the adult. Cut off within the cranial cavity, the embryonic buccal lobe assumes its intimate association with the cerebral lobe. In about the second month of fetal life it begins to develop numerous secondary diverticula which become the epithelial structures evident in the adult human subject.
Structure. — The posterior or cerebral lobe retains no organized structure. It may be said to consist of a mass of neuroglia and other fibrous connective tissue with the cells belonging to these and a moderate suppl}' of blood-vessels, with some sympathetic cell-bodies and fibres for the blood-vessels. The anterior or glandular lobe is probably the functional part of the organ. In addition to its abundant supporting tissue, it consists of compartments lined with two kinds of ouboidal cells — cells of different size and different staining properties. The principal or more numerous cells are smaller, with thicldy granular cytoplasm. In mi.xtures containing orange G and fuchsin these cells stain orange, while the chromophile cells, the larger and less numerous variety, take the fuchsin deeply. The compartments have an abundant blood supply. Near the interlobar septum, the cells frequently are arranged to form small vesicles which contain colloid substance, resembling the typical structure of the thyreoid body.
Like the epiphysis, the hypophysis must be regarded as glandular — a gland with internal secretion. In the case of giants and in acromegaly it is usually greatly enlarged. The principal cells increase greatly in number after removal of the thyreoid body.
THE OPTIC TRACTS
encephalon and mesencephalon. The optic apparatus consists of the retinae and optic nerves, the optic chiasma, the optic tracts, the superior quadrigeminate bodies with their relations with the nuclei of the eye-moving nerves, the metathalamus, the pulvinar of the thalamus, and the visual area of the cerebral cortex of the occipital lobe. The fibres of the optic nerves arise from the cells of the ganglion-cell layer of the retinae. The fibres which arise in the mesial or nasal halves of each retina cross the mid-line to find their nuclei of termination in the central grey substance of the opposite side, while those from the outer or lateral halves terminate on the same side (fig. 670.)
approach and fusion of the two optic nerves, and is knit together by the decussating fibres from the nasal halves of each retina, and, in addition, by the fibres of Gudden's commissure which is contained in it.
Beyond the chiasma the optic fibres continue as the optic tracts which course posteriorly around the cerebral peduncles to attain their entrance into the thalamenchephalon and mesencephalon. Upon reaching the pulvinar of the thalamus each optic tract divides into two roots, a lateral and mesial.
The lateral root contains practically all of the true visual fibres — fibres arising from the latera half of the retina of the same side and the nasal half of the retina of the opposite side. These fibres are distributed to three localities: — (1) part of them terminate in the lateral geniculate body; (2) the greater portion pass over and around the lateral geniculate body and enter the pulvinar; (3) a considerable portion enter the superior quadrigeminal brachium and course in it to terminate in the nucleus of the superior quadrigeminate body. The most evident function of this latter portion is to bear impulses which, by way of the neurones of the quadrigeminate body, are distributed to the nuclei of the oculomotor, trochlear, and abducent nerves, and thus mediate eye-moving refiexes. The cells of the lateral geniculate body and the pulvinar, about which the retinal fibres terminate, give off a.xones which terminate in the cortex of the visual area, chiefly the gyri about the calcarine fissure of the occipital lobe. In reaching this area they curve upward and backward, coursing in a compact band of white substance known as the optic
radiation (radiatio oocipito-thalamica, fig. 699). Whetlier any fibres of the optic radiation arise in tlie superor quadrigeminate body is doubtful. It also is in large part composed of fibres arising from the cells of the visual area, which pass from the cortex to the pulvinar, superior quadrigeminate bodies, and possibly some to the medulla oblongata and spinal cord.
The mesial root of the optic tract contains few true visual fibres. It runs into the medial geniculate body, and neither it nor this body are appreciably affected after extirpation of both eyes. It may be considered as largely representing the fibres of Gudden's commissure (inferior cerebral commissure). This commissure consists of fibres which connect the medial geniculate bodies of the two sides with each other, and which, instead of crossing the mid-line through the mesencephalon, course in the optic tracts and cross by way of the posterior portion of the optic chiasma. It consists of fibres which both arise and terminate in each of the bodies, and, therefore, of fibres coursing in both directions. It is also claimed that the fibres of Gudden's commissure connect the medial geniculate body of each side with the inferior colliculus of the opposite side.
The cerebral hemispheres in man form by far the largest part of the central nervous system. Together, when viewed from above, they present an ovoid surface, markedly convex upward, which corresponds to the inner surface of the vault of the cranium. The greater transverse diameter of this surface' lies posteriorly in the vicinity of the parietal eminences of the cranium. The outline of the superior aspect varies according to the form of the cranium, being more spheroidal in the brachycephalic and more ellipsoidal in the dolichocephalic forms. The hemispheres are separated from each other superiorly by a deep median slit, the longitudinal fissure, into which fits a duplication of the inner layer of the dura mater known as the falx cerebri. The posterior or occipital extremities of the hemispheres overlap the cerebellum, and thus entirely conceal the mesencephalon and thalamencephalon. They are separated from the superior surface of the cerebellum and the corpora quadrigemina by the deep transverse fissure. This is occupied by the tentorium cerebelli, which is similar to and continuous with the falx cerebri and is connected with the tela chorioidea of the third ventricle below.
Each of the hemispheres is usually described as having three poles or projecting extremities, and three surfaces bounded by intervening borders. The most anterior projection is the frontal pole. This is near the mid-line, and with its fellow of the other hemisphere, forms the frontal end of the ovoid contour of the cerebrum. The occipital pole is the most projecting portion of the posterior and inferior end, and is more pointed than the frontal pole. The infero-lateral portion of the hemisphere is separated anteriorly by the deep lateral fissure (fissure of Sylvius) into a distinct division, the temporal lobe, and the anterior portion of this lobe projects prominently forward and is known as the temporal pole.
The surfaces of the hemisphere are — (1) the lateral or convex surface; (2) the medial surface; and (3) the hasal surface. The convex surface comprises the entire rounded aspect of the hemisphere visible previous to manipulation or dissection, and is the surface subjacent to the vault of the cranium. The mesial surface is perpendicular, flat, and parallel with that of the other hemisphere, the two bounding the longitudinal fissure and for the most part in contact with the falx cerebri. The superomesial border intervenes between the convex and medial surfaces, and is thus convex and extends from the frontal to the occipital pole.
The more complex hasal surface fits into the anterior and middle cranial fossae, and posteriorly rests upon the tentorium cerebelh. Thus it is subdivided into — (a) an orbital area, which is slightly concave, since it is adapted to the orbital plate of the frontal bone, and is separated from the convex surface by the necessarily arched superciliary border and from the mesial surface by the medial orbital border, the latter being straight and extending from the frontal pole mesial to the olfactory bulb and tract; (fo) a tentorial area or surface, which is arched in conformity with the dorsal surface of the cerebellum. This is separated from the convex surface by the infero-lateral border, which runs from the occipital to the temporal pole; and from the mesial surface by the medial occipital border, which is a more or less rounded ridge extending from the occipital pole obliquely upward in the angle formed by the junction of the perpendicular falx cerebri and the horizontal tentorium cerebeUi. This border is best seen in brains which have been hardened with the membranes in situ. The remainder of the basal surface includes the ojDtic portion of the hypothalamus already considered, and the small
THE CORPUS CALLOSUM
depressed and punctate area, the anterior perforated substance, which is penetrated by the antero-lateral group of the central branches of the anterior and middle cerebral arteries and into which the striae of the olfactory trigone disappear. In addition to the orbital area the basal surface of the hemisphere shows signs of the impress of the petrous portion of the temporal bone and of the great wing of the sphenoid.
The corpus callosum. — In their early development as lateral dilations of the anterior primary brain-vesicles, the hemispheres are connected with each other only at the anterior end of the thalamencephalon, where they are both continuous with the lamina terminalis. As development proceeds and the hemispheres extend upward, backward, forward, and laterally to completely conceal the base,, and as the palhum, or cortex, thickens and its folds begin to appear, the two hemispheres become united across the mid-hne above the thalamencephalon and the third ventricle by the inter-growth of the great cerebral commissure, the corpus callosum. After removal of the falx cerebri from the longitudinal fissure, the
dorsal surface of the corpus callosum 'may be exposed by drawing apart the contiguous mesial surfaces of the hemispheres. It consists of a dense mass of pure white substance coursing transversely, and arises as out-growths from the cortical cells of both hemispheres. Thus it is the great pathway which associates the cortex of the two sides of the telencephalon. Only the smaller medial portion of the body lies free in the floor of the longitudinal fissure, by far the greater part being concealed in the substance of the hemispheres, where its fibres radiate to and from different localities of the pallium, forming the radiation of the corpus callosum. Its surface shows numerous transverse markings, the transverse strice, which indicate the course of its component bundles of fibres. In addition there may be seen two delicate, variable longitudinal bands running over its surface on each side of the mid-line. The medial longitudinal stria {stria Lancisii) runs close to the median plane, around the anterior end from the gyrus subcallosus (fig. 672), and over the posterior end downward and lateralward to disaiipcai' in the hippocampal gyrus of the base of the telencephalon. The lateral longitudinal stria is more delicate than the mesial stria, courses lateral to the medial stria, and can be seen only within the sulcus of the corpus callosum (fig. 672). Both striae are composed largely of axones having to do with the olfactory apparatus.
When severed along the median plane, it may be seen that the anterior margin of the corpus callosum is turned abruptly downward, forming the genu, and that this turn continues, so that the tapering edge of the body points posteriorly and
constitutes the rostrum (figs. 667, 671). The rostrum is in contact with the lamina terminalis of the third ventricle below by a short, thin, dorso-frontal continuation of this lamina, linown as the rostral lamina. The rostral lamina may be considered as beginning at the anterior cerebral commissure with the anterior aspect of which it is in contact, and extending to the rostrum. Beginning with the rostrum and genu, the corpus callosum arches backward as the body of the corpus callosum, and ends over the quadrigeminate region in its rounded, thickened posterior margin, the splenium. It is bounded above by the sulcus of the corpus callosum, and, attached to its concave inferior surface, are the chorioid tela of the third ventricle, the fornix, the septum pellucidum, and the medial walls of the lateral ventricles.
Each cerebral hemisphere includes — -(1) a superficial and much folded mantle or pallium, divided into lobes and gyri, and consisting of grey substance, the cortex, covering an abundant mass of white substance; (2) a modified portion, the
Transverse occipital sulcus
rhinencephalon, having especially to do with the impulses brought in by the olfactory nerve; (3) a cavity , the lateral ventricle; and (4) a buried mass of grey substance, the caudate and lenticular nuclei, which together with the internal capsule of white substance, are known as the corpus striatum.
Gyri, fissures, and sulci. — The cerebral pallium is thrown into numerous and variable folds or gyri (convolutions). These are separated from each other by corresponding furrows, tlie deeper and most constant of which are called fissures; the remainder, sulci. All the fissures and the main sulci are named. There are, however, numerous small and shallow sulci to which names are seldom given. These occur as short branches of main sulci or as short, isolated furrows bounding small gyri which connect adjacent gyri. These small gyri are likewise seldom given individual names. They are very variable both in different specimens and in the two hemispheres of the same specimen. Collectively, they are the so-called transitory gyri (gyri transitivi). Certain groups of them are named according to their locahty, such as orbital gyri and lateral occipital gyri. Even the main gyri [gyri profundi] (and sulci) are very irregular in detail. Some of the main and deeper fissures are considerably deeper than others. Some are infoldings of the grey cortex so deep that a portion of their course may be indicated as slight bulgings in the walls of the lateral ventricles, e. g., the hippocampal and collateral fissures. While the general surface pattern is similar for all normal human brains, yet when a detailed comparison is made, the given gyri of different specimens are found to
ever, are nearly alike.
Origin of the gyri. — The gjrri (and sulci) are the result of processes of unequal growth — folds necessarily resulting from the surface portion of the hemispheres increasing mucli more rapidly than the central core. In the early periods of fetal life the surfaces of the hemispheres are quite smooth. In many of the smaller mammals this condition is retained throughout life, but in the larger mammals, including man, as development proceeds the cerebral cortex becomes thrown into folds. The absolute amount of the grey substance of the hemispheres varies with the bulk of the animal, and apparently with its mental capabihties. This is especially true of the cortex, for in the larger brains, and that of man especially, by far the greater amount of the cerebral grey substance lies on the surface. Therefore, in either the growth or evolution of a smaU animal into a large one the amount of cerebral grey substance is increased, and in this increase the surface area of the brain is necessarily enlarged. It is a geometrical law that in the growth of a body the surface increases with the square, while the volume increases with the cube of the diameter. The cerebral hemisphere is a mass the increase of whose volume does not keep the required pace with the increase of its surface area or cortical layer. The white substance which forms the palUum arises in large measure as outgrowths from the cells of the cortical layer, and thus it can only increase in a certain proportion to the grey substance. Therefore, the surface mantle of grey substance of a hemisphere, enlarged in accordance with an increased bulk of body, is greater than is necessary to cover the surface of the geometrical figure formed by the combined white and grey substance. Consequently, in order to possess the preponderant amount of grey substance, the surface of the hemisphere is of necessity thrown into folds. It follows also that the thinner the cortical layer in proportion to the volume of the hemisphere, the greater and more folded will be the surface area. In accordance with this theory small animals have smooth or relatively smooth hemispheres, and that independently of their position in the animal scale or the amount of their inteUigence, while large animals have convoluted brains.
The sulci in general begin to appear with the fifth month of fetal life, the larger of them, the fissures, appearing first and in a more or less regular order. Up to the fifth month the encephalon, due to its rapid growth, closely occupies the cranial capsule. During the fifth month the cranium begins to grow more rapidly than the encephalon, and a space is formed between the cerebrum and the inner surface of the cranium. This space allows further expansion of the palUura, and at the time the space is relatively greatest (during the sixth month) the form and direction of the principal gyri and sulci begin to be indicated. As growth proceeds the unrestricted expansion of the pallium results in the gyri again approaching the wall of the cranium, and during the eighth month of fetal life they again come in contact with it. Finally, the later relative growth of the cranium results in the space found between it and the cortex in the adult. It is obvious that the relation of the cranium may be a factor in the causation of the gyri, for the increase of surface area necessitated by the increased amount of cortical grey substance might be limited by a cranial cavity of small size. It is probable that the second contact of the cortex with the cranium (during the eighth month) may at least cause a deepening and accentuation of the gyri already begun. Evidently the form of the cranium modifies the gyri, and to a certain extent probably determines their direction, for in long, dolichocephahe crania the antero-posterior gyri are most accentuated, and in the wide, brachycephalic crania the transverse gyri are most marked. At birth all the main fissures and sulci are present, but some of the smaller sulci appear later. In the growing pallium both the bottoms of the sulci as well as the summits of the gyri move away from the geometrical center of the hemisphere, the summits more rapidly, and hence the sulci or fissures first formed grow gradually deeper as long as growth continues.
The mechanical factors in the growth processes which result in the more or less regular arrangement of the gyri of the hemispheres of a given group of animals have not been satisfactorily determined. It has been suggested that the differences in arrangement of the gyri in different groups of animals may be in part dependent upon the functional importance of the various regions — the amount of grey substance of a region varying with the functional importance, and the consequent local increases being accompanied by resultant local foldings. This idea is supported by the fact that while the soma^sthetic (sensory-motor) area of the cortex varies with the bullc of the body, the frontal gyri, so much developed in man and which are one of the chief regions of the assooiational phenomena, are relatively independent of and do not vary with the weight of either the body or the brain.
Surface area. — The total surface area of the adult human telencephalon is about 2300 sq. cm. Of this area almost exactly one-third is contained on the outer or exposed surfaces of the gyri, while the other two-thirds is found in the walls of the sulci and fissures.
Lobes of the Telencephalon and the Gyri and Sulci
The folded pallium of each hemisphere is arbitrarily divided into lobes, partly by the use of certain of the main fissures and sulci as boundaries and partly by the use of imaginary Hues (figs. 672, 673). These divisions are sbc in number, themselves subdivided into their component gyri: —
This division of the cortex of the hemisphere is largely a merely topographical one. With the exception of the temporal lobe and the rhinencephalon, it has little of either morphological or functional value. The occipital lobe contains the recognised visual area of the cortex, but this area, as such, does not involve all of the lobe. In their functional significance, the frontal and parietal lobes, especially, overlap each other.
The temporal lobe. — This is the first lobe whose demarciition is indicated. During the second month of intra-uterine life there appears a slight depression on the lateral aspect of the then smooth hemisphere. As the pallium further grows, this depression deepens into a well-marked fossa with a relatively broad floor. This fossa marks the beginning of the lateral cerebral fissure or fissure of Sylvius, and is, therefore, known as the Sylvian fossa. As the pallium continues to project outward, the folds which form the margins of the Sylvian fossa increase in size and height and begin to overlap and conceal its broad floor, which is the beginning
Central sulcus of insula
of the insula. The overlapping folds thus become the opercula, and as their lips approach each other, there results the deep fissure of Sylvius, which marks off anteriorly an infero-lateral limb of the pallium, termed by position the temporal lobe. As growth proceeds further, the temporal lobe thickens, the temporal pole extends further forward and becomes a free projection, thus lengthening the fissure of Sylvius and resulting in the inferior extension or stem of this fissure, which runs between the temporal pole and the frontal lobe and curves under so as to appear on the basal surface of the hemisphere. Finally the cortex of the lobe itself is thrown into folds or gyri. Its posterior end is never marked off from the lobes above and behind, except by arbitrary fines which will be mentioned in connection with those lobes.
The temporal lobe forms part of the lateral convex and tentorial surfaces of the hemisphere, and its anterior portion is adapted to the surface of the middle cranial fossa. It thus has a superior and lateral surface and a basal and tentorial surface. In these surfaces are the following gyri with their intervening and bounding sulci (fig. 674) : —
The superior temporal gyrus is bounded by the posterior ramus of the lateral fissure, and extends from the temporal pole backward into the supra-marginal region of the parietal lobe above. The upper margin of this gyrus constitutes the temporal operculum, in that it aids in overlapping and enclosing the insula in the floor of the lateral fissure. This margin is for the most part smooth, being
THE TEMPORAL LOBE
occasionally interrupted by a few weak twigs of the lateral fissure. It is separated from the gyrus below by the superior temporal sulcus, which is parallel with the posterior ramus of the lateral fissure and is frequently called the parallel sulcus. The posterior extremity of this sulcus divides the angular gyrus of the parietal lobe, and its anterior end disappears in the temporal pole, sometimes as a continuous groove, sometimes in isolated pieces.
tinuous backward into the angular gyrus of the parietal lobe.
The inferior temporal gyrus forms the infero-lateral border of the temporal lobe, and is usually more broken up than the two gyri above it. It begins continuous with them in the frontal pole, and extends horizontally backward into the lateral gyri of the occipital lobe. It is separated from the middle gyrus by the middle temporal sulcus, which likewise is never so continuous a furrow as the superior temporal sulcus. Frequently this sulcus occurs in detached portions and often terminates within the temporal lobe.
The fusiform gyrus is in the basal and tentorial surface of the temporal lobe (fig. 676). Its usual somewhat spindle shape suggests its name, and it is continuous backward into the occipital gyri, or its posterior end may be completely isolated by a union of the inferior temporal sulcus and the collateral fissure, which two furrows separate it from its neighbours on either side. Anteriorly the fusiform gyrus runs into the common substance of the other three gyri at the temporal pole.
The lingual gyrus is usually included in the tentorial surface of the temporal lobe, though in some texts it is regarded as a part of the occipital lobe. Its larger, posterior portion lies within the boundaries of the occipital lobe. Bounded laterally by the collateral fissure, it is continuous anteriorly into the hippocampai gyrus of the rhinencephalon (fig. 676).
transverse temporal gyri.
The lateral fissure (fissure of Sylvius). — -As promised in its origin by the overlapping and enclosing of the broad floor of the Sylvian fossa by the adjacent folds of the pallium, the lateral fissure is the deepest and most conspicuous fissure of the cerebral hemisphere. Its main divisions are a short stem and three main branches. The stem lies in the basal surface of the hemisphere, where it begins
in a depression in the anterior perforated substance, the vallecula Sylvii, and passes forward and upward between and separating the temporal pole and the superciliary border of the frontal lobe. It corresponds in direction with the posterior border of the lesser wing of the sphenoid bone, which projects backward into it, and it contains the middle cerebral artery, the Sylvian vein, and the sinus alse parvse. It appears on the upper surface at a point known in cranial topography as the Sylvian point, where it divides into its three main branches : —
Superior temporal gyrus
These branches, together with certain smaller collateral twigs, divide the overlapping or opercular portions of the adjacent pallium into (a) the tem-poral operculum, which lies below the posterior ramus; {h) the fronto-parietal operculum, or operculum proper, which lies above and behind the anterior ascending ramus; (c) the frontal operculum,, between the latter and the anterior horizontal ramus; {d) and the orbital operculum, below the anterior horizontal ramus. Collectively the opercula are known as the opercula of the insula.
The insula (central lobe). — The insula or island of Reil is a triangular area of the cerebral cortex lying in the floor of the lateral fissure, and concealed by the opercula. Of these, the temporal operculum overlaps the insula to a greater extent than either the frontal or parietal. More than half of it may, therefore, be exposed, by gently pressing away the temporal lobe. The insula corresponds to the broad floor of the Sylvian fossa of the embryonic brain. In the developed condition its surface is convex lateralward and is itself folded into gyri. The apex of the triangle appears upon the basal surface of the hemisphere, and is the only portion which may be seen without disturbing the specimen. The apex appears as the end of a small gyrus under the temporal pole, and in close relation with the
anterior perforated substance and the vallecula Sylvii, and is known as the limen of the insula. In the folding process by which the opercula accomplish the overlapping and enclosing of the island, there results a deep sulcus which surrounds its entire area except at the limen insulse. This is known as the circular sulcus, or limiting sulcus of Reil. The gyri (and sulci) of the insula radiate from the apex of the triangle. The central sulcus of the insula is the deepest. It runs from below backward and upward, parallel with the central sulcus of Rolando above and divides the insula into a larger anterior and a smaller posterior portion. The anterior portion consists of from three to five short irregular gyri breves or precentral gyri, separated by sulci brevis ; the posterior portion consists of a single, slightly furrowed gyrus, which is long and arched and extends from the apex to the base of tlTe triangle, the gyrus longus.
In a recent study of the insula of more than 200 human brains, including a few of idiots and paralytics and a series of young fcetuses, Nelidoff finds that the left island is more deeply marked by sulci and averages 11 mm. longer than the right; that, of the sulci in the island, the central sulcus is the first to appear, is the most persistent sulcus in defective brains, though occasionally absent in microcephalic idiots, and that in the average it is more pronounced in males than in females.
The frontal lobe. — This is the most anterior of the lobes of the hemisphere, and hke the two lobes behind, it has a convex or lateral, a basal, and a mesial surface. The convex surface begins with the frontal pole, and is bounded posteriorly by the central sulcus {Rolandi). The basal surface extends backward to the stem of the lateral fissure, covered by the frontal pole. The mesial surface is separated from the gyrus cinguli of the rhinencephalon (limbic lobe) by the subfrontal part of the sulcus cinguli (calloso-marginal fissure), and from the parietal lobe by a line drawn perpendicularly from the upper extremity of the central sulcus (Rolandi) to the sulcus cinguli. These surfaces include the following gyri and sulci: — •
Rostral sulci.
Many of the sulci, especially the superior frontal and the rostral sulci, often give off twigs or are broken up into short furrows which give rise to small folds [gyri transitivi], too inconstant to be given special names.
The anterior central gyrus (ascending frontal convolution) is the only gyrus of the frontal lobe having a vertical direction. It lies parallel to the central sulcus (Rolandi), and thus extends obliquely across the convex surface from the posterior ramus of the lateral fissure (frontal operculum) to the supero-mesial border, and is continuous on the mesial surface with the anterior portion of the para-central lobule. It comprises the larger part of the motor portion of the somsesthetic (sensory-motor) area of the cerebral cortex. It is separated from the horizontal frontal gyri in front of it by the precentral sulcus.
This sulcus is developed in three parts, but the upper and middle parts in the foetal brain usually fuse together, so that in the later condition it consists of a superior and an inferior segment. The superior cuts the supero-mesial border of the hemisphere and appears on the mesial surface in the paracentral lobule. On the convex surface it is usually cormected with the posterior end of the superior frontal sulcus (fig. 674).
The superior frontal gyrus is a relatively broad, uneven convolution, comprising the anterior portion of the supero-mesial border of the hemisphere, and therefore extends horizontally from the precentral sulcus to the frontal pole. It is sometimes inperfectly divided into a superior and an inferior part by a series of
detached, irregular furrows, spoken of collectively as the para-medial sulcus. The resulting transitory gyri are of considerable interest in that they are peculiar to the human brain, and are said to be more marked in the higher than in the lower types.
The middle frontal gyrus is likewise a broad strip of pallium extending from the precentral sulcus to the temporal pole. It is separated from the superior frontal gyrus by the superior frontal sulcus, which is usually continuous into the superior section of the precentral sulcus and thence extends horizontally to the frontal pole. The middle frontal gyrus is in most cases subdivided anteriorly into a superior and an inferior portioii by a middle frontal sulcus. This sulcus begins above and runs into the frontal pole, where, upon reaching the superciliary border, it frequently bifurcates into a transverse furrow, known as the Jronto-marginal sulcus.
The inferior frontal gyrus forms the superior wall of the lateral fissure, and is separated from the middle frontal gyrus by the inferior frontal sulcus. This sulcus usually begins continuous with the inferior section of the precentral sulcus, and extends, very irregularly and frequently interrupted, toward the frontal pole. The gyrus abuts upon the anterior central gyrus, and its posterior portion is divided into three parts (the frontal opercula) by the anterior ascending and horizontal rami of the lateral fissure. The part behind the anterior ascending ramus is the opercular portion (a part of the fronto-parietal operculum or operculum proper), sometimes referred to as the basilar portion. In most brains this part is traversed by a short oblique furrow, the diagonal sulcus. The part between the two anterior rami of the lateral fissure is the cap-shaped triangular portion. This portion frequently involves one and sometimes two descending twigs of the inferior frontal sulcus. The part below the anterior horizontal ramus is by position the orbital portion.
It is seen that the inferior frontal gyrus gives rise to the whole of the frontal operculum and the antei'ior half of the fronto-parietal operculum. The opercular portion is of special interest in that in the left hemisphere it constitutes the celebrated convolution of Broca, the motor area for the function of speech. The area controlling speech, however, involves that part of the triangular portion bounding the anterior ascending ramus of the lateral fissure as well, and both these parts often appear more developed on the left hemisphere. The development of the opercula of the inferior frontal gyrus is a distinctive characteristic of the human brain. This gyrus does not develop opercula even in the highest varieties of apes. The development of the function of speech in man no doubt influences the development of the frontal opercula.
On the basal surface (fig. 676) of the frontal lobe is the orbital area and the gyrus rectus. The more pronounced of the orbital sulci are often so joined with each other as to form an H-shaped figure standing parallel to the mesial plane, and thus they comprise a medial, a lateral and a transverse orbtial sulcus. This figure naturally divides the orbital area into four gyri: — (1) The lateral orbital gyrus is tlie basal continuation of the inferior frontal gyrus, and is thus related to the orbital portion of the frontal operculum; (2) the anterior orbital gyrus is continuous at the pole with the middle frontal gyrus; (3) the posterior orbital gyrus is closely related to the limen insulse and the stem of the lateral fissure, and its outer part is in relation with the orbital portion of the operculum ; (4) the medial orbital gyrus is continuous over the superciliarj^ border with the superior frontal gyrus. It frequently contains one or two short, isolated sulci. Its mesial boundary is the straight olfactory sulcus, in which lies the olfactory bulb and tract of the rhinencephalon. This sulcus marks off a narrow straight strip of cortex between it and the mesial border of the lobe known as the gyrus rectus. The posterior portion of the gyrus rectus comprises a part of the parolfactory area or Broca's area, which functionally belongs to the rhinencephalon. As an area or field, this appears mesially lying between the anterior and posterior parolfactory sulci.
On the mesial surface (fig. 679), of the frontal lobe the superior frontal gyrus is separated from the gyrus cinguli of the rhinencephalon (limbic lobe) by the wellmarked sulcus cinguli. Anteriorly the superior frontal gyrus is subdivided by the main stem of the rostral sulci into a marginal gyrus, and what may be termed a sub'marginal gyrus. The marginal gyrus is usually broken into smaller parts by twifi's of the rostral sulci, most of which are perpendicular to the main stem, while the submargJnal gyrus is less frequently interrupted. Posteriorly the superior frontal gyrus constitutes the anterior portion of the paracentral lobide, a part of
usually marked off anteriorly by a vertical twig from the sulcus cinguli.
The sulcus cinguli (calloso-marginal fissure) is the longest and one of the most prominent sulci on the mesial surface of the hemisphere. It divides the anterior portion of the mesial surface into a marginal part above and a callosal part below — in other words, it separates the superior frontal gyrus from the gyrus cinguli. Its subfrontal portion begins below the rostrum of the corpus callosum and curves forward and upward around the genu, and then turns backward above the body of the corpus callosum. Before it reaches the level of the splenium, it turns upward and cuts and terminates in the supero-mesial border of the hemisphere, as the next sulcus behind the upper termination of the central sulcus. This upward
Longitudinal fissure
turn is the marginal portion of the sulcus cinguli. It is sometimes an abrupt curve and sometimes curves gradually, but its marginal relation to the upper end of the central sulcus is so constant that it serves as a means by which either of the sulci may be identified. The marginal portion separates the paracentral lobule from the precuneus (quadrate lobule), and is wholly within the parietal lobe. One of the most constant twigs of the sulcus cinguli is that which marks off the paracentral lobule from the superior frontal gyrus. Another sometimes divides the paracentral lobule into its frontal and parietal portions.
The sulcus cinguli is developed from two and sometimes three (anterior, middle, and posterior) separate furrows, which later extend and fuse into continuity. This metliod of its development may explain the irregularities frequently met with and the fact that sometimes in the adult the sulcus occurs in separate pieces.
The central sulcus (fissure of Rolando) (figs. 674, 678) is one of the principal landmarks of the convex surface of the hemisphere. It separates the frontal from the parietal lobe, and likewise divides the somsesthetic area of the palUum. Its
upper end terminates in and usually cuts the supero-mesial border of the hemisphere immediately in front of the termination of the marginal portion of the sulcus cinguli. Thence it pursues an oblique though sinuous course forward across the convex surface of the hemisphere, forming on the average an angle of about 72° with the supero-mesial border (Rolandic angle), and terminates in the frontoparietal operculum immediately above the posterior ramus, and about 2.5 cm. behind the point of origin of the anterior rami of the lateral fissure. It rarely cuts through the fronto-parietal operculum. In its sinuous course, varying from the line of its supero-mesial end, two bends are marked (fig. 677) : — (1) The superior genu occurs at about the junction of the upper and middle thirds of the sulcus and is concave forward. It accommodates the greater part of that portion of the cortex which is the motor area for the muscles of the leg and trunk, and the development of this area in man probably aids in producing it. (2) The inferior genu occurs below, is concave forward and is commonly a little more marked than the superior genu. It is probably in part a result of the superior genu — the turn of the sulcus in resuming its general course, but it may further result from the development of the shoulder and arm area of the cortex which occupies its concavity.
Fig. 677. — Diagram Representing the Most Common Form of the Central Sulcus and Indicating the Regions of Junction upon it of the Areas of the Peecenteal Gyrus Devoted to the Dipfeeent Regions of the Body, as Estimated by Symington and Crymble.
Operculum
The central sulcus (Rolandi) appears in the pallium of the fcetus during the latter part of the fifth month. It then consists of a lower longer and an upper shorter part. Usually these two parts become continuous before birth; very rarely do they remain separate in the adult. The point of their fusion is sometimes manifest within the depth of the sulcus. If the lips of the sulcus be pressed widely apart at about the region of the junction of its middle and upper thirds, it will be found that the opposing walls give off a number of protuberances or lateral gyri, which dovetail into each other when the sulcus is closed. Sometimes two of these lateral gyri appear fused across the floor of the sulcus, so as to form a bridge of grey substance known as the deep annectant gyrus. This interruption of the continuity of the sulcus, when present, represents the point at which the two parts of the sulcus in the fcctal brain joined each other without the continuity becoming wholly completed in the adult. The genua of the adult sulcus may often be due to the precedent parts not being ia hne at the time of their fusion.
From a special study of the central sulcus of 237 normal adult hemispheres, Symington and Crymble (1913) give the following details: (1) that the most common course of the sulcus is that illustrated in fig. 677, above; (2) that it varies in depth both in a given specimen and in different specimens — the greatest variations in depth reported for a given sulcus being from 22 to 12 millimeters, the shallowest part being in the region of the deep annectant gyrus; (3) that the average length from the supero-mesial border of the hemisphere to the opercular end of the sulcus is about 9 cm. in direct line and 10.4 cm. following the curves of the sulcus. The average length of the curved floor is 7.9 cm. (4) From the supro-meisal end of the sulcus to the points of junction of the general areas of the precentral gyrus, direct line measurements give averages, (a) to the junction of leg and trunk areas, 3.5 cm.; (b) to junction of trunk and arm areas, 4.5 cm.; (c) to junction of arm and face areas, 7.5 cm.
The parietal lobe. — The parietal lobe occupies a somewhat smaller area of the human telencephalon than either the frontal or the temporal lobe. It has a convex and a mesial surface, but no basal surface. It is separated from the frontal lobe in front by the central sulcus; from the occipital lobe behind, on the mesial surface by the parieto-occi-pital fissure (fig. 650), and, on the convex surface,
by an arbitrary line drawn transversely around the convex surface of the hemisphere from the superior extremity of this fissure to the infero-lateral border; and it is separated from the temporal lobe below by the horizontal part of the posterior ramus of the lateral fissure, and by a line drawn in continuity with this horizontal part to intersect the transverse line drawn to limit it from the occipital lobe.
. The preoccipital notch. — In situ, the infero-lateral border of the posterior portion of the hemisphere rests over a small portion of the parieto-mastoid suture of the cranium, and upon this structure occurs a fold or vertical thickening of the dura mater, which slightly indents the infero-lateral border. This indentation occurs about 4 cm. from the occipital pole, and is considered one of the points of hmitation of the parietal from the occipital lobe, and is therefore called the preoccipital notch. While during late foetal Ufe and early childhood it is well marked, it is usually very shght in the adult bram, and is, as a rule, evident only in brains hardened
in situ. When it is visible, the arbitrary transverse line from the superior extremity of the parieto-occipital fissure, used as a boundary, between the convex surfaces of the parietal and occipital lobes, should be so drawn as to bisect the preoccipital notch.
The convex surface of the parietal lobe comprises the following gyri and sulci : — The posterior central gyrus (ascending parietal) extends obliquely across the hemisphere parallel with the anterior central gyrus of the frontal lobe, from which it is separated by the central sulcus. Its inferior end is bounded by the posterior ramus of the lateral fissure, and constitutes the posterior or parietal portion of the fronto-parietal operculum. Its upper end takes part in the supero-mesial border of the hemisphere, and is bounded posteriorly by the tip end of the marginal portion of the sulcus cinguli. Its postero-lateral boundary consists of the two more or less vertical rami or factors of the interparietal sulcus, viz., the inferior and superior portions of the postcentral sulcus, either continuous -nith each other or detached.
The interparietal sulcus (intraparietal) is often the most complicated sulcus of the pallium. Its development usually begins as four different furrows in the foetal brain, and the difficulty with which it is traced in the adult brain depends
upon the extent to which these four factors become continuous in the later development. When continuity of the furrows is well established, the entire sulcus may be described as consisting of a convex horizontal ramus, which gives off a few short collateral twigs and wliose either end is in the form of an irregular, reclining -\ . The transverse bar of the anterior end arises fron two of the four factors of the entire sulcus: — (1) an inferior furrow, the inferior postcentral sulcus, commencing above the posterior ramus of the lateral fissure and ascending as the boundary of the lower half of the posterior central gyrus, and (2) a superior furrow, the superior postcentral sulcus, lying behind the upper portion of the posterior central gyrus, and which, upon approaching the supero-mesial border, may turn backward a short distance parallel with the horizontal ramus, as in fig. 674. When confluent, these two factors form together a continuous postcentral sulcus. In the adult the inferior of the two is always continuous with the horizontal ramus; when confluent, the two figures join so as to form the transverse bar of the anterior end of this ramus. The horizontal ramus, which represents the
\ \ \ Rostum of corpus callosum , v^ \ Anterior parolfactory sulcus \ \ Parolfactory area (Broca's area) \ Posterior parolfactory sulcus Sub-callosal gyrus (peduncle of / corpus callosum)
Tuber cinereum Infundibulum
third of the primary furrows, is continued backward past the superior extremity of the parieto-occipital fissure into the occipital lobe, where it usually joins the occipital ramus, the fourth of the primary furrows. This ramus divides shortly into two branches which run at right angles to the stem, forming the transverse occipital sulcus, and thus arises the transverse bar of the posterior end of the interparietal sulcus. The occipital ramus may, however, consist of little more than the transverse bar, which may or may not be joined by the horizontal ramus. The occipital ram.us is more frequently separate from the horizontal than is the postcentral sulcus. In their development the inferior postcentral sulcus appears first (during the latter part of the sixth month), the occipital ramus second, the horizontal ramus third, and last, the superior postcentral sulcus.
The superior parietal lobule (gyrus) is the area of the supero-mesial border of the parietal lobe. It is limited in front by the superior postcentral sulcus, below by the horizontal ramus of the interparietal sulcus, and posteriorly it is continuous around the superior end of the parieto-occipital fissure into the cortex of the occipital lobe. It is a relatively wide area (lobule),' always invaded by collateral twigs of its limiting sulci, and usually contains a few short, isolated furrows. When the parieto-occipital fissure is considerably prolonged over the supero-mesial border (external parieto-occipital fissure), the continuation of the
The inferior parietal lobule is limited in front by the inferior postcentral sulcus, and above by the horizontal ramus of the interparietal sulcus. It is continuous with the cortex of the temporal lobe below, and with that of the occipital lobe behind, and is therefore invaded by the ends of the sulci belonging to these lobes. Its anterior portion is separated from the temporal lobe by the horizontal portion of the posterior ramus of the lateral fissure. The upturned end of this ramus invades the anterior portion of the lobule and the broad fold, arched around this end and continuous behind it into the superior temporal gyrus, is known as the supramarginal gryus — the area to which auditory word- and tone-images are attributed. The angular gyrus is the portion which embraces the posterior end of the superior temporal sulcus, and is continuous behind this into the middle temporal gyrus and in front with the superior temporal gyrus. It is the area for visual word images. Its shape is usually such as to suggest its name. The most posterior part of the inferior parietal lobule, when arching in a similar way about the end of the middle temporal sulcus and continuous with the temporal gyri on its either side, is known as the post -parietal gyrus. This is a smaller area than either of the other two, and, owing to the variability of the end of the middle temporal sulcus, is not always evident.
The mesial surface of the parietal lobe is divided into two parts by the marginal portion of the sulcus cinguli. The anterior and smaller part is the mesial continuation of the posterior central gyrus, and comprises the posterior portion of the paracentral lobule. It is limited from the part of this lobule belonging to the frontal lobe by a vertical line drawn from the marginal extremity of the central sulcus. The praecuneus {quadrate lobule) is the posterior and larger part of the mesial surface of the parietal lobe. It is separatd from the cuneus of the occipital lobe by the parieto-occipital fissure, and is imperfectly separated from the gyrus cinguli (limbic lobe) below by the sub-parietal sulcus (postlimbic fissure), branches of which invade it extensively.
The occipital lobe. — This is a relatively small, trifacial, pyramidal segment, comprising the posterior extremity of the hemisphere, its apex being the occipital pole. Though one of the natural divisions of the cerebral hemisphere, it is very indefinitely marked off from the lobes anterior to it. Though it contains the cortical area of the visual apparatus, only in the brains of man and the apes does it occur as a well-defined posterior projection. In most of the mammalia it is not differentiated at all. Its three surfaces comprise a convex, a mesial, and a tentorial surface.
Its convex surface is separated from that of the parietal and temporal lobes by the superior and external extremity of the parieto-occipital fissure, and by an arbitrary line drawn transversely from this extremity to the infero-lateral border of the hemisphere, or so drawn as to bisect the pre-occipital notch when this is evident. The sulci which occur on the convex surface may be described as two, though both of these are very variable in their e.xtent and shape, and their branches are inconstant both as to number and length. (1) the transverse occipital sulcus is the most constant in shape. It extends a variable distance transversely across the superior portion of the lobe, and, as noted above, it is frequently continuous with the interparietal sulcus through its occipital ramus, and when so, it appears as the posterior terminal bifurcation of this sulcus (fig. 674). When detached, it often occurs merely as a definite furrow with few rami, and sometimes the ramus by which it otherwise would join the interparietal sulcus is entirely absent. (2) The lateral occipital sulcus is always short, and has its deepest portion below the transverse sulcus. It usually has a somewhat oblique course toward the supero-mesial border. Sometimes it occurs in several detached pieces, then known collectively as the lateral occipital sulci.
Therefore, the gyri of the convex surface of the lobe are also variable. They are not sufficiently constant to merit individual names. The lateral occipital sulcus or sulci roughly divide them into an inferior and lateral area, known as the lateral occipital gyri, and into a uperior larea, the superior occipital gyri. The lateral area is continuous into the gyri of the temporal lobe, while the superior area is continuous into the gyri of the parietal lobe.
marked parieto-occipital fissure. It comprises the constantly defined, wedgeshaped lobule known as the cuneus, and the posterior and mesial extremitj'- of the lingual gyrus. Since the greater portion of the length of the lingual gyrus is involved in the basal surface of the temporal lobe, this gyrus as a whole has been considered as belonging to the temporal lobe (see figs. 671, 676). The cuneus is separated from the hngual gyrus by the posterior portion of the calcarine fissure, which always terminates in a bifurcation, one limb of which invades the cuneus near the superomesial border. In addition the cuneus may contain other twigs from both the fissures bounding it, and also, when wide, may contain one or more short, detached sulci cunei.
The calcarine fissure and the parieto-occipital fissure are almost invariably joined in the human brain, forming a Y-shaped figure, the prongs of which give the cuneus its shape. The calcarine fissure begins on the tentorial surface in the posterior portion of the hippocampal gyrus of the Umbic lobe, below the splenium of the corpus callosum, and extends backward across the internal occipital border of the hemisphere. It then bends downward and proceeds to its terminal bifurcation in the polar portion of the occipital lobe. The stem or hippocampal portion of the fissure is deeper than the posterior or occipital portion. It produces a wellmarked eminence in the medial wall of the posterior cornu of the lateral ventricle, known a^ the calcar avis or hippocampus minor. It is developed separately from the posterior portion, which itself first appears as two grooves. All three parts are usually continuous with each other before birth.
The parieto-occipital fissure usually appears from the first as a continuous groove. It begins in the supero-mesial border of the hemisphere, rarely extending into the convex surface more than 10 mm. (external parieto-occipital fissure), thence it extends vertically downward across the mesial surface (internal parieto-occipital fissure), and terminates by joining the calcarine fissure at the region of the downward bend of the latter, or at about the junction of its anterior and middle thirds. In certain of the lower apes and in the brain of the chimpanzee there is no junction between the two fissures, they being kept apart by a narrow neck of cortex, the gyrus cunei. Neither are they joined in the human foetus. If in the adult human brain the region of their'junction be opened widely, there will be found a submerged transitory gyrus (deep annectant gyrus), which is the gyrus cunei, superficial in the fcetus. Two other transitory gyri (annectant gyxi) are to be found by pressing open the calcarine fissure, and they mark the points at which its three original grooves became continuous during its development into a boundary between the cuneus and the lingual gyi'us. Of these, the anterior cuneo-lingual gyrus crosses the floor of the calcarine fissure on the posterior side of its junction with the parieto-occipital fissure, and therefore near the gyrus cunei. The posterior cuneolingual gyrus occurs near the region of the terminal bifurcation of the fissure.
The tentorial surface of the occipital lobe is blended intimately with that of the temporal lobe, from which it is separated only by an arbitrary line drawn to join the line of demarcation for the convex surface, at the region of the preoccipital notch, and thence to the isthmus of the gyrus fornicatus — the narrow neck of cortex connecting the gyrus cinguh with the hippocampal gyrus, just below the splenium of the corpus callosum (see fig. 671). The gyri blending the occipital and temporal lobes across this fine are the lingual gyrus, already mentioned, and the fusiform gyrus (occipito-temporal convolution). In fact, the tentorial surface of the lobe may be considered as nothing more than the posterior extremity of the fusiform gyrus, and the inferior portion of the same extremity of the lingual gyrus. The former is often somewhat broken up and is then continuous into the lateral occipital gyri. The two gyri are separated by the collateral fissure the posterior end of which extends into the occipital lobe. The fusiform gyrus is bounded laterally by the inferior temporal sulcus, which sometimes is continuous by a lateral twig, across the posterior end of this gyrus, with the collateral fissure.
The rhinencephalon or olfactory brain includes those portions of the cerebral hemisphere which are chiefly concerned as the central components of thie olfactory apparatus. Owing to the preponderant development of the other divisions of the hemisphere, the parts comprising this division appear relatively but feebly developed in the human brain. In most of the mammals the sense of smell is relatively much more highly developed, and in many of the larger mammals the parts comprising the rhinencephalon are of greater absolute size than in man, though their cerebral hemispheres may be considerably smaller. In the human foetus the parts of the rhinencephalon are relatively much more prominent than after the completed differentiations into the adult condition. In the broader
sense of the term the rhinencephalon includes those parts of the hemisphere usually classed as comprising two lobes, viz., the olfactory lobe and the limbic lobe. Neither of these is a 'lobe' in the sense of comprising a definite segment of the hemisphere, as do the other lobes, and therefore the rhinencephalon cannot be called a distinct lobe. It is so strung out that by one or the other of its parts it is either in contact or continuity with each of the other lobes of the hemisphere.
(1) The olfactory bulb is an elongated, oval enlargement of grey substance which lies upon the lamina cribrosa of the ethmoid bone, and, practically free, it presses under the anterior end of the olfactory sulcus in the basal surface of the frontal lobe. The numerous thin filaments of nonmeduUated axones of the olfactory nerve enter the cranium through the foramina of the lamina cribrosa and pass into the ventral surface of the bulb.
Hippocampal gyrus
(2) The olfactory tract is a triangular band of white substance which arises in the olfactory bulb, and continues backward about 20 mm. to the region of the anterior perforated substance. It appears triangular in transverse section from the fact that its upper side fits into the olfactory sulcus. It becomes somewhat broader at its posterior end.
(3) The olfactory trigone {olfactory tubercle) is the small triangular ridge, the posterior continuation of the olfactory tract joining the anterior perforated substance. In it the olfactory tract breaks up into three roots, the lateral, intermediate, and medial olfactory strice {gyri). The lateral olfactory stria emphasizes the lateral portion of the trigone into the lateral olfactory gyrus, a portion of which is directly continuous into the lijnen insulce (figs. 676, 680).
While a few of the fibres of the lateral stria penetrate this region, the greater mass of them pass obhquely lateralward over it and gradually disappear in the antero-lateral portion of the anterior perforated substance, in which some of them terminate, but through which most of them pass to curve into the anterior end of the hippocampal gyrus and terminate there, chiefly in the uncus. In most of the mammals the lateral stria is so strong that it appears as a superficial white band passing directly into the uncus. In the early foetus it is seen to enter the uncus in two branches, forming the medial semilunar gyms and the lateral gyrus ambiens upon the uncus. A portion of the limen insulce belongs to the rhinencephalon.
(4) The parolfactory area (Broca's area) involves the mesial extension of the olfactory trigone, and is concerned with the medial olfactory stria. On the basal surface of the hemisphere this area involves the posterior extremity of the gyrus rectus — a portion of which is sometimes separated from the remainder of the gyrus by a ventral prolongation of the anterior parolfactory sulcus of the medial surface (see figs. 679, 706). This prolongation when present has been called the fissura serotina. On the medial surface the parolfactory area appears as a
definite gyrus. In front this is separated from the superior frontal gyrus by the anterior -parolfactory sulcus, and from the subcallosal gyrus behind by the deeper posterior parolfactory sulcus (fig. 679) . It is continuous above into the gyrus cinguli of the limbic lobe, a portion of the posterior part of the rhinencephalon.
A large portion of the fibres of the medial stria are lost in the parolfactory area, and are known to terminate about the cells there. This stria or root of the olfactory tract forms a slight ridge on the ventral surface of the area, which is frequently pi-ominent enough to retain the name medial olfactory gyrus appUed to it in the foetal brain (fig. 680).
(5) The subcallosal gyrus (peduncle of the corpus callosum) is the narrow fold of the pallium which lies between the posterior parolfactory sulcus and the rostral lamina and the ventral continuation of the latter into the lamina terminalis. It begins above, in part fused to the rostrum of the corpus callosum, and in part continuous with the gyrus cinguli, and ventrally it goes over lateral ward and posteriorly into that portion of the anterior perforated substance known as the diagonal band of Broca, and in this way it extends into the uncus. Mesially, it approaches its fellow of the opposite side so closely that the groove separating the two is known as the median subcallosal sulcus of Retzius. Some fibres of the medial olfactory stria disappear in the substance of the subcallosal gyrus.
(6) The anterior perforated substance must be considered with the rhinencephalon, but, like the limen insulae, it can only be considered as belonging in part to this division of the brain. It comprises the basal region between the optic chiasma and tract and the olfactory trigone. Usually the posterior parolfactory sulcus (fissura jmnia of the embryo) is sufficiently evident to more or less distinctly separate it from the latter. Its postero-lateral area is occupied by the diagonal band of Broca. A few fibres from the medial stria are known to disappear within its depths, and, as mentioned above, many fibres from the lateral stria also pass into it. The intermediate olfactory stria is always much the weakest of the three striae, and in many specimens is apparently absent. The fibres of this stria run almost straight backward and plunge directly into the anterior area of the anterior perforated substance, where some of them are known to terminate, while others continue into the uncus.
The olfactory bulb and tract arise as a hollow outgrowth from the lower and anterior part of the anterior of the three primary vesicles. It is a tubular structure at first, and in many of the mammals the cavity maintains throughout hfe as the olfactory ventricle. In man the cavity becomes occluded and the ependyma and gelatinous substance which surround it become the grey core of the bulb and tract of the adult.
The grey substance persists and develops chiefly in the bulb, and in fact produces it as such. It is much thicker on the inferior surface of the bulb than on the superior surface, and in section shows definite layers. From within outward, the principal of these layers are — (1) the layer of large cells whose shape suggests their name, mitral cells; (2) large dendrites of the mitral cells project toward the inferior surface of the bulb and there break up into numerous telodendria which copiously form synapses with like telodendria of the entering fibres of the olfactory nerve, thus forming rounded, much tangled glomeruli and the layer containing these, the glomerular layer; (3) the superficial layer, or olfactory layer, consists of the fibres of the olfactory nerve which form a dense interlacement with each other on the inferior surface of the bulb before they pass into its interior. The superior surface of the bulb becomes formed almost wholly of the fibres which arise as axones of the mitral cells and pass backward to form the olfactory tract, and thence to their localities of termination, chiefly by way of the three striiE. Along the dorsal, covered, aspect of the olfactory tract the gelatinous substance of the core may show through as a grey ridge.
name introduced by Broca in 1878) takes part in both the medial and tentorial surfaces of the hemisphere (fig. 681). Seen from the medial surface, it forms an irregular eUiptical figure which encloses the corpus callosum and the extremities of which approach each other at the anterior perforated substance, where they are continuous with the structures of the anterior division of the rhinencephalon. The figure is bounded externally by the sulcus cinguU above, by the subparietal sulcus (postlimbic sulcus) and the anterior limb of the calcarine fissure behind, and by the collateral fissure below. These respectively separate it from the frontal, parietal, occipital, and temporal lobes. It comprises the following
Dentate fascia or gyrus
Being an incomplete ellipse in form, its two ends are united to form a closed ring by means of the connection of the parolfactory area with the gyrus cinguli and the connection of the anterior perforated substance with the uncus of the hippocampal gyrus. It is best described in terms of its three component parts indicated above:
The gyrus cinguli begins in junction with the area parolfactoria below the anterior end of the corpus callosum, and curves above so as to entirely embrace the upper surface of the latter. It is separated from the frontal lobe by the sulcus cinguli (calloso-marginal fissure), from the parietal lobe by the subparietal sulcus, and from the corpus callosum below by the sulcus of the corpus callosum. By the latter it is separated from the longitudinal strite of the upper surface of the corpus callosum.
The gyrus cinguli covers over, and its cells are closely associated with, the cingulum, a wellmarked arcuate band of white substance, which follows the gyrus in its bend around the rostrum and backward to turn around the splenium of the corpus callosum in the isthmus of the gjTus fornicatus, and then to course forward into the hippocampal gyrus and the uncus. The cingulum is largely an association fasciculus between the gjTi of the temporal lobe and those gyri on the mesial surface of the cerebral hemisphere, its fibres for the most part running short courses, being continually added to it and continually leaving it. However, it contains olfactory axones running in two directions: (1) fibres from the medial olfactory stria and fibres arising in the parolfactory area, the gyrus subcaDosus and the anterior perforated substance which course posteriorly for distribution in the cortex of the gjTUs cinguli and hippocampal gyrus; (2) fibres arising in the hippocampal gyrus, especially the uncus, to course dorsalward through the isthmus and then forward as association fibres. Some fibres arising from the cortical cells of the g3TUS cinguli pass inferiorly through the cingulum, through the corpus callosum and, anteriorly, through the septum pellucidum to join the fornix below {perforating fibres of Ike fornix).
and incloses the posterior turn of the cingulum.
The hippocampus is the name applied to the curved appearances produced in the floor of the lateral ventricle by the peculiar foldings of this part of the cerebral cortex. The hippocanipal gyi'us (gyrus of the hippocampus) is the main gyrus of the tentorial surface of the hmbic lobe. Externally it is separated from the fusiform gyrus by the collateral fissure, and it is bounded internally by the hippocampal or, more inclusive, the chorioid fissure. Posteriorly it is partially divided by the calcarine fissme into the lingual gyrus (of the temporal lobe) and the isthmus of the gyrus fornicatus. Its anterior extremity is hooked backward and is known as the uncus {gyrus uncinatus) . This is almost entirely separated from the temporal lobe by a groove, the temporal notch. If the hippocampal fissure be opened up, the dentate gyrus or fascia and the fimbria will be seen. These lie side by side, separated by the shallow fimbrio -dentate sulcus (fig. 690.)
The free edge of the dentate gyrus presents a peculiarly notched appearance, produced by numerous parallel grooves cutting it transversely. Its posterior end, sometimes called the fasciola cinerea, continues backward over the splenium of the corpus callosum, and upon the upper surface of the corpus callosum appears as a thin strip of grey substance which contains embedded in it the medial and lateral longitudinal strice. This thin strip is sometimes called the supracallosal gyrus (gyrus epicallosus, induseum griseum), and is thought to represent a vestigial part of the hippocampal gyrus. Closely beneath the splenium of the corpus caUosum, on the supero-mesial side of the hippocampal gyrus and mesial to the dentate gyrus, there sometimes occur suggestions of round or oval elevations of the grey substance which have been called the "callosal convolutions" or gyri Andrece Retzii. Rarely are they strongly developed, but when so they often produce a spiral appearance.
The fimbria is but the fimbriated, free border of the posterior end or origin of the fornix, so folded as to project into the hippocampal fissure, parallel with the dentate gyrus (fig. 690). It is a conspicuous iDand composed almost entirely of white substance, continuous laterally with the thick stratum covering the ventricular surface of the hippocampus. It begins anteriorly in the hook or recurved extremity of the uncus. Traced backward, it is seen so curve upward, and within the ventricle it becomes part of the general accumulation of the white substance (alveus) of the surface of the hippocampus, which accumulation is the beginning of the fornix. The free border of the fimbria (seen in section) is known as the tcenia fimhrim. The fimbria is separated from the cerebral peduncles by the chorioid fissure, the thin, non-nervous floor of which alone intervenes between the exterior of the brain and the cavity of the lateral ventricle within.
The hippocampal fissure attains its greatest depth between the dentate gyrus and the hippocampal gyrus, and the resulting eminence produced in the floor of the lateral ventricle is known as the hippocampus major, as distinguished from the lesser eminence produced posteriorly by the end of the calcarine fissme and known as the hippocampus minor [calcar avis]. The collateral fissure may likewise produce a bulging in the wall of the ventricle, the collateral eminence. In transverse sections of the hippocampus major, the layers of grey and white substance present a coiled appearance known as the cornu ammonis. Externally the medial surface of the hippocampal gyrus adjoining the dentate gyrus has reflected over it a delicate reticular layer of white substance known as the substantia reticularis alba (Arnoldi).
The fornix is the great association pathway of the limbic lobe, and appears to be wholly concerned in the apparatus of the rhinencephalon. It is a bilateral structure arched beneath the corpus callosum, with which it is connected anteriorly by the septum pellucidum. Posteriorly it passes in contact with the splenium. It consists of two prominent strips of white substance, one for each hemisphere, the ends of which are separate from each other, while their intermediate parts are fused across the mid-line. These run above the chorioid tela of the third ventricle, and their lateral edges (tcenice fornicis) rest, on each side, along the line of the taenia chorioidea. The posterior, separate ends are known as the posterior pillars or crura of the fornix; the fused, intermediate portion is the body, and the separate, anterior ends are the anterior pillars or columns of the fornix.
The posterior pillars [crura] of the fornix. — When seen from the medial aspect of the hemisphere, the fused portion of the fornix, in the separation of the hemispheres, is split along the mid-line (fig. 671). The half under examination
may be seen to course obliquely lateralward under the splenium of the corpus callosum, and then, continuous into the fimbria, to curve forward and ventralward toward the uncus. The greater mass of the fibres coursing in the fornix arise as outgrowths of the cells of the uncus, hippocampal gyrus, and dentate gyrus. They accumulate as a dense stratum on the ventricular surface of these gyri, termed the alveus, which crops outward as the fimbria and which passes backward and upward; upon reaching the region of the splenium it turns obliquely forward under
it and approa(3hes the mid-line, to fuse with the hke bundle from the gyri of the hippocampus of the opposite side. The bundles thus arising from the two sides are the pillars or crura of the fornix. They appear as two flattened bands of white substance which come in close contact with and even adhere to the splenium.
The angle formed by the mutual approach of the posterior pillars of the fornix is crossed by a lamina of commissural fibres connecting the hippocampal gyri of the two hemispheres (fig. 684). This lamina is the hippocampal commissure or transverse fornix. Like those of the fornix, its fibres arise from the cortex of the hippocampal gyri, but they serve as commissural fibres between the hippocampal gyri of the two hemispheres. Being of a different functional direction, it should not be considered a part of the fornix. The angle formed by the two pos-
Mammillary body
terior pillars of the fornix as traversed by the hippocampal commissure gives a picture named the psalterium or lyra. Usually the hippocampal commissure and the posterior pillars (crura) are in close contact with the under surface of the splenium. When occasionally they do not adhere, the space between is known as Verga's ventricle. According to recent studies of brains with degenerated corpus callosum, further commissural fibres between the limbic lobes course in the posterior angle of the septum pellucidum, and all along, transverse to the body of the fornix.
The body of the fornix appears as a triangular plate of white substance produced by the fusion of the pillars. Its base or widest portion is behind. It is not always bilaterally symmetrical. Its upper surface is attached by the septum
pellucidum to the lower surface of the corpus callosum. Below, it lies over the chorioid tela of the third ventricle, which separates it mesially from the cavity of the third ventricle and laterally from the upper surfaces of the thalami. Its sharp lateral edge or margin (taenia fornicis) projects into the lateral ventricle of either side in relation with the chorioid plexus of that ventricle, and thus the lateral portion of its upper surface forms part of the floor of the lateral ventricle — an arrangement to be expected, since the posterior pillars arise from the floor of
Fig. 684. — Horizontal Section of Telencephalon showing Bodt of Fornix and HippoCAMPAL Commissure as seen from Below and the Anterior Commissure in Section. (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
layer of ependyma in common with that lining the rest of the ventricle.
Along its body the fornix receives fibres arising from the cells of the cortex of the gjTus cinguli and fibres from the longitudinal striaj upon the dorsal surface of the corpus callosum. These are known as the perforating fibres of the fornix. In their ventral course, they pass obliquely forward through the corpus callosum and, anteriorly, through the posterior angle of the septum pellucidum to join the fornix and course in its functional direction. Tlie fibres arising in the cortex of the gyrus cinguli may course short distances in the cingulum before perforating the corpus callosum.
The columns or anterior pillars of the fornix [coluranse fornicis], are two separate, cyhndrical bundles which pass forward from the apex of the body of the fornix and then turn sharply downward along the anterior boundary of the third ventricle, just behind the anterior cerebral commissure. A part of each column, the /ree portion [pars libera], forms the anterior boundary of the interventricular foramen (Monroi). Thence the covered portion [pars tecta] sinks into the grey
ANTERIOR CEREBRAL COMMISSURE 871
substance of the lateral wall of the third ventricle, and passes downward to the base of the brain, where it appears on the exterior as the mammillary body [corpus mammillare] (fig. 671).
Some of its fibres are interrupted in the nuclei of the mammillary body, chiefly in its lateral nucleus; probably most of them merely double back, forming a genu. From the mammUlary body the fibres are disposed in at least three ways: — (1) The greater part perhaps pass directly upward and are lost in the anterior nucleus of the thalamus, where they ramify freely and terminate about its cells. These fibres form the bundle known as the mammillo-thalamic fasciculus, or bundle of Vicq d'Azyr; (2) A portion of the fibres go to form a mammillo-mesencephalic fasciculus (tegmento-mammiilary fasciculus, mammillo-peduncular fasciculus. This begins in the mammillary body and passes caudalward into the mesencephalon to terminate about cell-bodies in or in the region of, the so-called nucleus of the medial longitudinal fasciculus and posterior commissure. Fibres given by these cell-bodies may convey impulses by way of the medial longitudinal fasciculus or the general reticular formation to the nuclei in the mesencephalon, rhombencephalon and perhaps into the spinal cord. Some of this portion of the fibres from the mammillary body are said to pass caudalward through the mesencephalon without interruption there. (3) A portion of the fibres decussate in the superior parts of the mamillary bodies and are distributed to both the thalamus and the mesencephalon of the opposite side. This decussation is the supraraamillary commissure.
As seen above, the fornix as a whole is composed of longitudinally directed fibres, some of which, however, cross the mid-line in the region of its body and course in the columns of the opposite side. For the greater part, its fibres rise from the cells of the hippocampal gyri, but it is known to contain some fibres which arise in the anterior perforated substance and subcallosal gyrus and course through the fornix to the hippocampal gyri.
The medial and lateral longitudinal striae upon the corpus callosum consist of olfactory fibres coursing in both directions: (1) fibres arising in the parolfactory area, the subcallosal gyrus and the anterior perforated substance (diagonal band of Broca) course posteriorly and then inferiorly in them to the grey substance of the gryi of the hippocampus; (2) and chiefly, fibres from the hippocampal gyri course in them anteriorly and inferiorly around the rostrum of the corpus callosum, through the ventral part of the septum pelluoidum, to join the fornix. It is suggested that the strise, especially the medial, may be considered as a part of the fornix detached upon the dorsal surface of the corpus callosum during the projection of the latter between the cerebral hemispheres. The medial stria is often called the stria Lancisii.
The anterior cerebral commissure is only in part concerned in the rhinencephalon; it consists in greater part of commissural fibres connecting the two temporal lobes. It forms one of the four commissures of the telencephalon, the other three being the corpus callosum, the hippocampal commissure and the inferior cerebral commissure. It is a bundle of white substance with a slightly twisted appearance, which crosses the mid-line in the anterior boundary of the third ventricle between the lamina terminalis and the columns of the fornix (figs. 671 and 684), just below the interventricular foramen (foramen of Monro). In each hemisphere its main or temporal portion passes lateralward and slightly backward beneath the head of the caudate nucleus and through the anterior end of the lenticular nucleus, and thence is dispersed to the grey substance of the temporal lobe.
It contains fibres both to and from the temporal lobe of each side. In addition to these fibres the anterior commissure carries in its frontal side two sets of fibres belonging to the olfactory apparatus: — (1) fibres arising in the olfactory bulb of one side, which pass by way of the medial olfactory striae through it to the olfactory bulb of the opposite side; (2) fibres which pass through it from the medial stria (olfactory bulb) of one side to the uncus of the opposite side.
The anterior commissure is a more primitive commissure than the corpus callosum, in that it is present in the lower forms when the latter is absent, and diminishes in relative size and importance as the corpus callosum appears and increases in size. In man the appearance of the anterior commissure precedes but little that of the corpus callosum. During the fifth month the lamina terminalis, which then alone unites the anterior ends of the two hemispheres, develops a thickening of its dorsal portion. In a part of this thickening, transverse fibres begin to appear and their increase in number results in the partial separation posteriorly of the part containing them from the rest of the lamina, and then follows the differentiation of this part into the anterior commissure. The remainder of the thickening of the lamina continues to increase in size with the increase of the hemispheres; its upper edge is directed posteriorly, and fibres begin to appear in it which arise in the cortex of one side and cross over to that of the other side. These fibres form the corpus callosum.
The corpus callosum, a development of fibres in the upper, expanded portion of the lamina terminalis, thus bridges over a portion of the longitudinal fissure between the hemispheres. In the mean time, the /ornts arises as two bundles of fibres, one from the hippocampus of each side. In the complex mechanics of the development of the cerebrum these two bundles approach each other under the corpus callosum, fuse for a certain distance, and together arch the cavity of the third ventricle and come to acquire their adult position. There results from these processes of growth a completely enclosed space, a portion of the longitudinal fissure, the roof of which is the corpus callosum, its floor, the body of the fornix, and its lateral walls, portions of the mesial surfaces of the two cerebral hemispheres. The lateral walls of this space do not thicken
The septum pellucidum is a thin, approximately triangular, vertically placed partition which separates the anterior portions of the two lateral ventricles from each other. Its widest portion lies in front, bounded by the genu and rostrum of the corpus callosum, the rostral lamina, and the anterior pillars of the fornix, to all of which it is attached. Prolonged backward under the body of the corpus callosum, it narrows rapidly and terminates at the line of adherence between the posterior portion of the fornix and the splenium of the corpus callosum. It consists of two thin layers, the laminae of the septum pellucidum, arrested developments of portions of the pallium of the hemispheres. The laminae enclose a narrow median cavity known as the fifth ventricle [cavum septi pellucidi]. This cavity is of very variable size, is completely closed, and does not merit the term ' ventricle, ' as apphed to the other cavities of the brain, in that it has no communication with the ventricular system and has a different lining from the other ventricles.
Olfactory epithelium
Each lamina of the septum pellucidum consists of a layer of degenerated grey substance next to the fifth ventricle and a layer of white substance next to the lateral ventricle, the latter covered by a layer of ependyma common to that ventricle. The white substance consists in part of fibres belonging to the general association systems of the hemispheres, and in part of four varieties of fibres concerned with the rhinencephalon: — (1) fibres from each medial olfactory stria are known to reach the septum pellucidum and thence go by way of the fornix to the hippocampus major; (2) fibres are thought to be contributed by the fornix to the septum pellucidum, and through it reach the subcallosal gyrus and perhaps the parolfactory area and even the olfactory bulb ; (3) the posterior angle of the septum pellucidum is preforated by some commissural fibres passing from the body of the fornix and by some perforating fibres of the fornix, passing from above through it to the fornix below; (4) anteriorly, some fibres from the longitudinal strife upon the corpus callosum pass tlirough its inferior portion to join the fornix.
The medullary stria of the thalamus [stria meduUaris thalami] {striai pinealis, lamia thalami), already described as to position, receives fibres from three sources, the majority at least of which belong to the rhinencephalon: (1) fibres from the fornix near-by and thus from the cortex of hippocampal gyrus and gryus cinguli (a cortico-habenular tract) ; (2) fibres from the parolfactory area and the anterior perforated substance, through the septum pellucidum and lamina terminahs (a more direct olfaoto-habenular tract) ; (3) fibres arising from the cell-bodies in the thalamus, supposedly chiefly from its anterior (olfactory) nucleus. These latter fibres make a thalamo-habenular tract.
The majority of the fibres of the medullary striae terminate in the habenular nuclei, situated at the two sides of the stalk of the epiphysis. Most terminate in the habenular nucleus of the same side. Some cross in the habenular commissure (dorsal part of the posterior cerebral commissure) and terminate in the nucleus of the opposite side. A few are claimed to pass to the nuclei of the quadrigeminate bodies and a few others to join the association tracts of the mesencephalon. Axones given off by the cells of the habenular nucleus curve anteriorly, inferiorly, and then course posteriorly (fasciculus retroflexus) to terminate in the interpeduncular nucleus
THE LATERAh VENTRICLES 873
(a hahenulo-peduncular tract), and fibres arising in this latter nucleus pass to the cells about the central grey substance of the mesenecphalon (an inter-pedunculo-tegmental tract). The two mesencephalic paths here noted and the mammillo-mesencephalic fasciculus noted above give three anatomical possibilities for olfactory reflex activities, visceral (or sympathetic) and somatic, involving the motor cranial nerves and possibly the spinal nerves. Fibres arising in the cortex of the hippocampal gyrus, uncus especiaDy, may pass by way of the cingulum and thence by any suitable association fasciculus of the cerebral hemisphere to the motor area of the cerebral cortex; also fibres may arise from the anterior nucleus of the thalamus and pass to the motor cortex by way of the internal capsule. From the motor cortex, the descending pyramidal fibres give the possibihties for any higher cortical activities induced by smell.
A more direct mesencephahc path has been suggested by Wallenberg, namely, that cells in the olfactory trigone and anterior perforated substance, about which terminates fibres of the olfactory tract, send axones directly postei-iorly, ai'ound the tuber cinereum, to terminate in the mammiUary body and thence the impulses may go to the mesencephalon. Such fibres, if they exist, would form an olfacto-mammillary tract. A path is described in the hedge-hog which arises from cells in the olfactory trigone and passes directly posteriorly to terminate in the grey substance of the mesencephalon — an olfacto-mesencephalic tract.
To the complicated central connections of the sense of smell, Dejerine adds yet another path, namely, a portion at least of the terminal stria [stria terminalis] of the thalamus (taenia semicircularis). This contains fibres arising from cells in the anterior perforated substance and in the septum pellucidum and fibres from the opposite side by way of the anterior commissure. It runs a crescentic course posteriorly, bounding the thalamus from the caudate nucleus, turning downward and then anteriorly in the wall of the inferior cornu of the lateral ventricle to terminate in the amygdaloid nucleus, which latter is a more or less detached bit of the cortex of the extreme anterior portion of the hippocampal gyrus (uncus). The stria is said also to contain fibres which arise in the amygdaloid nucleus and course in it forward to be given off to the thalamus and probably to the internal capsule and thence to the cerebral cortex above.
(2) Non-meduIIated central processes of olfactory neurones, the olfactory nerve, passing as numerous filaments through the cribriform plate of the ethmoid, to terminate in contact with the dendrites of the "mitral cells" (stratum glomerulosum) in the olfactory bulb.
Two of the four cavities of the ventricular system of the brain are in the telencephalon. From their position, one in each cerebral hemisphere, they are known as the lateral ventricles. They arise as lateral dilations of the cavity of the anterior of the prhnary vesicles, and, just as the fourth ventricle remains in communication with the third by way of the aqueduct of the cerebrum, so the lateral are connected with the third by the two interventricular foramina (Monroi). The whole ventricular system, including the central canal of the spinal cord, is Hned by a continuous layer of ependyma and contains a small quantity of liquid known as the cerebro-spinal fluid.
Each lateral ventricle is of an irregular, horseshoe shape. It consists of a central portion or body and three cornua, which correspond to the three poles of the hemisphere. The portion projecting into the frontal lobe is known as the anterior cornu, that projecting into the occipital lobe is the posterior cornu, and the portion which sweeps anteriorly downward into the temporal lobe is the inferior cornu. The ventricles of different individuals vary considerably in capacity, and the cavity of a given ventricle is not uniform throughout. In some
localities the space may be quite appreciable, while in other places the walls may be approximate or even in apposition. Each lateral ventricle is a completely closed cavity except at the interventricular foramen. However, a strip of the floor of the inferior cornu is separated from the exterior of the brain by only the thin, non-nervous lamina forming the floor of the chorioid fissure.
nel, 2 to 4 mm. wide, which opens into the mesial side of the posterior end of the anterior cornu. It is bounded in front by the free portion of the anterior pillars of the fornix, and behind by the anterior tubercle of the thalamus. That the greater part of the lateral ventricle is posterior to it is due to the backward extension of
each other.
The walls of the lateral ventricle. — The anterior cornu is a bowl-like cavity, convex forward and extending downward and medial ward into the frontal lobe. Above and anteriorly it is bounded by the under surface of the corpus callosum and the radiations of its genu into the substance of the frontal lobe. Its median boundary is the septum pellucidum; the head of the caudate nucleus (part of the corpus striatum) gives it a bulging, infero-lateral wall, and the balance of its floor is formed by the white substance of the orbital part of the frontal lobe.
The central portion or body is more nearly horizontal. It lies within the parietal lobe and extends from the interventricular foramen to the level of the splenium of the corpus callosum. Its roof is formed by the inferior surface of the body of the corpus callosum, and its mesial wall consists of the posterior part of the septum pellucidum, attaching the fornix to the under surface of the corpus callosum. Like the anterior horn, it is given an oblique, infero-lateral wall by the narrower, middle part of the caudate nucleus. Several structures contribute to its floor: — (1) the stria terminalis of the thalamus, a hne of white substance conforming to the genu of the internal capsule without, and constituting the
Fig. 688. — Horizontal Dissection of the Cerebral Hemispheres. The fornix has been removed to show the relation of the tela chorioidea of the third ventricle to the chorioid plexus of the lateral ventricles. (From a mounted specimen in the Anatomical Department of Trmity College Dulilin )
Straight sinus.
boundary between the caudate nucleus and the thalamus, and containing (2) the vena terminalis (vein of the corpus striatum); (3) the lamina affixa, a mesial continuation of the stria terminalis upon the surface of (4) the lateral part of the thalamus; (5) the medial edge of the lamina affixa, the tsenia chorioidea, and the chorioid plexus continuing under (6) the edge (taenia) of the body and the beginning crura (posterior pillars) of the fornix (fig. 688).
The chorioid plexus of the lateral ventricle is continuous with that of the third ventricle. The chorioid tela of the third ventricle (velum interpositum) continues under the taenia of the fornix into the lateral ventricle, and there, along the line of the taenia chorioidea, becomes elaborated into a varicose, convoluted, villus-like fringe, rich in venous capillaries and lymphatics. This fringe is the chorioid plexus. It is continuous anteriorly, at the interventricular foramen, with the corresponding plexus of the opposite lateral ventricle and with the chorioid plexus of the third ventricle. The latter consists of two similar but smaller fringes, which project close together into the cavity of the third ventricle from the median portion of the ventral surface of the chorioid tela. Behind, the chorioid
plexus of the lateral ventricle curves posteriorly and inferiorly into the inferior cornu, being especially well developed at the region of its entrance into the latter, into what is called the chorioid glomus.
Though apparently lying free in the ventricle, the chorioid plexus is invested throughout by a layer of epithelium, the epithelial chorioid lamina, which is adapted to all its unevennesses of surface and which is a continuation of the ependymal lining of the remainder of the ventricle — continuous, on the one hand, with that of the lamina affixa and thalamus, and, on the other, with the epithehal covering upon the upper surface of the tania of the fornix and fimbria.
The posterior cornu of the lateral ventricle is a crescentic cleft of variable length, convex lateralward, which is carried backward from the posterior end of the body of the ventricle and, curving medialward, comes to a point in the occipital lobe. Its roof and lateral wall are formed by a portion of the posterior radiation of the corpus callosum, which forms a layer, from its appearance known as the tapetum. In transverse sections of the occipital lobe (fig. 699) the tapetum appears as a
thin lamina of obliquely cut white substance immediately bounding the cavity, while outside the tapetum occurs a thicker layer of more transversely cut fibres, the occipito-thalamic radiation. In the medial or inner wall of the posterior horn run two variable longitudinal eminences: — (1) The superior of these is the bulb of the posterior cornu, and is formed by the occipital portion of the radiation of the corpus callosum (splenium), which bends around the impression of the deep parieto-occipital fissure, and, hook-like, sweeps into the occipital lobe. In horizontal sections these fibres, together with the splenium and the similar fibres into the opposite occipital lobe, form the figure known as the forceps major. (2) The inferior and thicker of the eminences is the hippocampus minor [calcar avis] (cock's spur), and is due to the anterior part of the calcarine fissure, by which the wall of the hemisphere is projected into the ventricle. The posterior horn, like the anterior, is not entered by the chorioid plexu i.
The inferior cornu. — In its inferior and slightly lateral origin from the region of junction between the body of the ventricle and the posterior cornu, the inferior horn aids in producing a somewhat triangular dilation of the cavity known as the collateral trigone. Beginning as a part of the trigone, the cavity of this horn at first passes posteriorly and lateralward, but then suddenly curves anteriorly and
inferiorly into the medial part of the temporal lobe nearly parallel wdth the superior temporal sulcus. Above, it follows the curved crura (posterior pillars) of the fornix and fimbria; below, it does not extend to the temporal pole by from 2 to 3 cm. The roof and lateral wall are, for the most part, like those of the posterior horn, being formed by the tapetum, but medialward a strip of the roof is formed by the attenuated, inferior prolongation, or tail, of the caudate nucleus, together with the inferior extension of the stria terminalis of the thalamus. At the end of the inferior horn the roof shows a bulging, the amygdaloid tubercle, situated at the termination of the tail of the caudate nucleus. This bulging is produced by the amygdaloid nucleus, an accumulation of grey substance continuous with that of the cortex of the hippocampal gyrus, and which gives origin to part of the longitudinal fibres coursing in the stria terminalis of the thalamus.
In the medial wall and floor of the inferior horn the follo'ning structures are shown: — (1) In the posterior or trigonal part of the floor is the longitudinal collateral eminence, a bulging, very variable in development in different specimens, produced by the collateral fissure. This is often pronouncedly in two parts, a posterior prominence corresponding to the middle portion of the collateral fissure and an anterior prominence (less frequent) produced by the anterior part of the
Collateral fissure
fissure. (2) Medial to this eminence lies the inferior extension of the chorioid plexus, usually more voluminous than the part in the bodj^ of the ventricle. (3) Partly covered by the chorioid plexus is the hippocampus major, a prominent, sickle-like ridge corresponding to the indentation of the hippocampal fissure. It begins as a narrow ridge posteriorly, at the end of the body of the ventricle, as the extension of the posterior pillar of the fornbc, and expands anteriorly as the ventricular surface of the uncus. Its surface is not regular, but shows a concave medial margin as distinguished from a wider, convex, lateral sm'face. Its termination in front (pes hippocampi) is divided by two or three flat, radial grooves into a corresponding number of short elevations known as the hippocampal digitations. It is covered by a thick stratum of white substance, the alveus, arising from its depths and continued mesially into the fimbria. (4) The fimbria is so folded that its margin, ta:nia fimhrice, lies in the cavity of the inferior horn attached to the chorioid plexus and the thin, non-nervous floor of the chorioid fissure.
The caudate nucleus (fig. 691). — As realised in the study of the lateral ventricle, the caudate nucleus is a comma-shaped mass of grey substance with a long, much-curved, and attenuated tail. Its head forms the bulging lateral wall of the anterior horn; thence it proceeds posteriorly in the lateral wall of the body of the ventricle and, at the collateral trigone, curves downward and its tail becomes
a medial portion of the roof of the inferior horn. It is separated from the thalamus adjacent to it by the stria terminalis of the thalamus (taenia semicircularis). The end of its tail extends anteriorly below to the level of the anterior horn of the ventricle above. Owing to its much curved shape, both horizontal and vertical sections of the hemisphere passing through the inferior horn may contain the nucleus cut at two places (see figs. 694 and 698.)
The caudate nucleus is the intraventricular of the two masses of grey substance which together are sometimes referred to as the basal ganglia. The extraventricular of these masses is the lenticular nucleus, which is bmied in the substance of the hemisphere, laterally and inferior to the caudate nucleus. The two masses
Fig. 691. — Diageams of Lateral View and Sections op the NtrcLEi of the Corpus Striatum WITH THE Internal Capsule Omitted. A and B below represent horizontal sections along the lines A and B in the figure above. The figure also shows the relative position of the thalamus and the amygdaloid nucleus.
Internal capsule
are separated by the internal capsule, a thick band of nerve-fibres continuous into the cerebral peduncles, and connecting the grey cortex of the hemisphere with the structures inferior to it. Anteriorly and below, the two nuclei become continuous and the white substance of the internal capsule, in separating them posteriorly, contributes to the striated appearance in sections, known collectively as the corpus striatum (figs. 692, 695) . The corpus striatum as such is described below.
From the above examinations of their external and ventricular sinfaces, it is apparent that the cerebral hemispheres consist of a folded, external mantle of grey substance, the cortex cerebri, spread more or less evenly over an internal mass
THE LENTICULAR NUCLEUS 879
of white substance which contains embedded within it certain masses of grey substance, the chief of which are known as the caudate and lenticular nuclei of the corpus striatum. In addition, the hemispheres of the telencephalon overlie and are in functional connection with the structures of the diencephalon below, the chief of which are the thalamencephalon and the bases of the cerebral peduncles.
The grey substance of the telencephalon. — The grey substance is in intimate relation with the white substance, and in fact its cells give origin to the greater part of the fibres composing the white substance. The accumulations of grey substance to be considered are the cerebral cortex, with its variations in thickness and arrangement, the corpus striatum, the claustrum, and the amygdaloid nucleus.
The cerebral cortex [substantia corticalis] is distributed over the entire surface of each hemisphere except the peduncular region of the base and the region of the corpus callosum and fornix of the medial surface. Numerous measmrements have been made to determine its average thickness. These have shown that the mantle is not uniformly distributed: — (1) that it is thicker on the convex surface than on the basal and medial surfaces; (2) that on the convex smrface it is thicker on the central region of the hemisphere, somsesthetic area, than at the poles; (3) that in the average normal specimen it averages somewhat thicker on the left than on the right hemisphere; (4) that its average thickness varies greatly in different individuals, and that the thickness decreases with old age; (5) that it is probably somewhat thicker in males than in females, and (6) that in a given specimen it averages thicker on the summits of the gyri than in the floor of the corresponding sulci. In the normal adult conditions it averages about 4 mm. thick on the anterior and posterior central gyri, in the somsesthetic area, while it attains its mimimum thickness of about 2.5 mm. on the basal surface of the occipital and frontal lobes. Its total average thickness is about 2.9 mm. The practically nonnervous floor of the third ventricle and that of the chorioid fissure are very much thinner but are not considered in these measurements.
The cerebral cortex consists of layers of the cell-bodies of neurones, chiefly of the pyramidal type (fig. 604), which receive impulses from the structures below and from other regions of the cortex by way of fibres reaching them through the internal mass of white substance, and which in turn contribute fibres to the white substance. Certain fibres of shorter course and numerous collateral branches of fibres passing out of the cortex are devoted to the association of the region of their origin with the cortex of the immediate vicinity of their origin, and most of these course within the grey cortex itself. In certain gyri, such as the anterior central gyri and those of the medial surface of the occipital lobe, these short association fibres accumulate into strata, and in vertical sections give the cortex a stratified appearance. Two such strata of white substance may be noted in the above localities, one lying about midway in the thickness of the cortex and one slightly internal to this. They are known as the inner and outer stripes of Baillarger. In addition, a thin, superficial or tangential layer of fibres may often be distinguished lying in the surface of the cortex. Transverse sections through the anterior end of the hippocampus show a coiled arrangement of the layers of white substance, to which has been given the name cornu ammonis. The peculiar structure and appearance of the olfactory bulb and tract, parts of the cortex, have already been mentioned.
The corpus striatum is so called on account of the appearance in section of its component parts, the caudate and lenticular nuclei (basal ganglia) and the internal capsule between them. The two nuclei are directly continuous with each other at their anterior ends (fig. 691), and in addition they are connected by numerous small bands of grey substance which pass from one to the other through the internal capsule, especially its anterior part. Also each nucleus contributes numerous fibres to, and receives fibres from, the internal capsule. These bundles of fibres both arising and terminating within the nuclei, together with the grey substance among the fibres of the capsule, produce the ribbed and striped appearance suggesting the name, corpus striatum. The caudate nucleus — the intraventricular part of the corpus striatum — hes with its thicker anterior part (head) closely related to the internal capsule, but its tail passes posteriorly around the posterior border of the capsule and curves downward and anteriorly into the roof of the inferior cornu of the lateral ventricle.
The lenticular nucleus [nucleus lentiformis] — the extraventricular part of the corpus striatum — is embedded in the white substance of the cerebral hemisphere. It is somewhat pyriform in shape, not being so long as the caudate nucleus, and neither having a tail nor extending so far anteriorly. Its lower surface is separated from the inferior cornu of the lateral ventricle by the white substance of the roof of that cornu, and by the tail of the caudate nucleus, and, fur-
ther forward, the anterior commissure passes through its base. Its lateral surface is rounded and conforms both in extent and curvature with the surface of the insula, from which it is separated by the fibres of the external capsule and the intervening claustrum. Its oblique superior and mesial surface is adapted to the lateral surface of the internal capsule, and it comes to a rounded apex in the angle formed by the internal capsule and a plane parallel with the base of the hemisphere. In both horizontal and coronal (transverse) sections through its middle it resembles a compound biconvex lens. Internally this appearance is produced by two vertically curving laminae of white substance, an external and an internal medullary lamina, which divide its substance into three zones: — the two medial zones together form an area, triangular in section, known as the globus pallidus ; the lateral, larger and more grey, concavo-convex zone is the putamen. Radiating fibres from the medullary laminae extend into the zones, especially those of the globus pallidus. These zones disappear in transverse sections of the anterior
portion of the lenticular nucleus (fig. 692), due to the fact that the larger putamen alone comprises this portion and alone becomes continuous with the caudate nucleus. (See figs. 691, 696.)
Connections. — Both nuclei of the corpus striatum become continuous with the cortex in the region of the anterior perforated substance, and the putamen of the lenticular nucleus may blend with the anterior part of the base of the claustrum. The following are the principal fibre connections: — (1) Fibres arising in the nuclei which join the internal capsule to reach the cerebral cortex, and fibres arising in the cortex which descend by the same course to the cells of the nuclei. (2) Fibres which pass in both directions between the thalamus and the corpus striatum (caudate nucleus especially). These are more abundant anteriorly, and necessarily pass through the internal capsule. (3) The ansa lenticularis, or strio-subthalamio radiation, a usually distinct lamina, composed largely of fibres passing inferiorly between the thalamus and lenticular nucleus. It passes from the basal aspect of the anterior tubercle of the thalamus and curves below through the internal capsule to the basal surface of the lenticular nucleus, and there its fibres are distributed upward through its medullary lamina to the globus pallidus and putamen. Some enter the internal capsule and reach the cortex, chiefly that of the temporal lobe. The ansa lenticularis also contains fibres from the cortex of the temporal lobe to terminate in the inferior and mesial parts of the thalamus. The fibres associating the thalamus with the temporal lobe belong to the so-called inferior peduncle of the thalamus. (4) Fibres connecting both nuclei (chiefly the caudate) with the red nucleus and substantia nigra of the mesencephalon. These pass through the hypothalamic region and along the cerebral peduncle. No definitely localised functions have been with certainty ascribed to either nucleus. They serve as 1-elays in the pathways associating the cortical grey substance with the structures below and in them the neurones concerned in these pathways are greatly increased.
surface is concave, conforming to the convexity of the putamen. The sheet of white substance intervening between it and the putamen is known as the external capsule. Its lateral surface shows ridges or projections in section which conform to the neighbouring gyri of the insula, and it is spread through an area which quite closely coincides with that of the inusla. Below and anteriorly it becomes continuous with the cortex of the anterior perforated substance and with the lenticular nucleus at the region of the junction of these. Above and posteriorly it gradually becomes thinner, and finally disappears in the white substance about it. In origin it is thought to be a detached portion of the cortical grey substance of the insula.
The amygdaloid nucleus [nucleus amygdalae] is represented by the amygdaloid tubercle, which has already been described in the extremity of the inferior cornu of the lateral ventricle (figs. 666 and 691). It is an almond-shaped mass of cells joined to the tail of the caudate nucleus, continuous above with the putamen and anteriorly continuous with the cortex of the hippocampal gyrus.
Fig. 693. — Coronal Section op Telencephalon through the Anterior Commissure, Optic Chiasma, and Trunk op Corpus Callosum. (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.) Caudate nucleus
of lateral i
The chief connections of the amygdaloid nucleus by way of the stria tertjiinalis of the thalamus are noted above under the description of the posterior division of the rhinencephalon. The amygdaloid nucleus, like the claustrum, is thought to represent a detached portion of the cortex, it being detached from the uncus. Considering this and its chief connections, it, with the stria terminahs of the thalamus, are concerned in the central portion of the olfactory apparatus.
The thalamus and hypothalamus. — The external features of these portions of the prosencephalon have been described in their natural place, but inasmuch as they contain the chief relays between the telencephalon and the divisions of the nervous system caudal to the prosencephalon, the consideration of their internal structure has been deferred till now. The principal grey masses to be considered are the thalamus and the hypothalamic nucleus. The structures comprising the metathalamus and epithalamus have already been mentioned in their relations with the mesencephalon and the optic and auditory apparatus.
The thalamus has upon its upper surface, under its ependyma, a thin stratum zonale of white substance, derived in part from the incoming fibres and in part from its own cells. Its oblique lateral surface conforms to the medial surface of the internal capsule; its vertical medial surface forms the lateral wall of the third ventricle, and below it is continuous into the hypothalamic (tegmental) region.
Its upper surface shows a middle, an anterior, and a posterior prominence or tubercle. The anterior tubercle (nucleus) forms the posterior boundary of the interventricular foramen; the posterior tubercle is the cushion-like pulvinar which projects backward over the lateral geniculate body and the brachium of the superior quadrigeminate body.
A horizontal section through the supero-medial edge, spHtting the stria medullaris of the thalamus and thus passing above the massa intermedia, shows the grey mass of the thalamus divided into segments or nuclei by a more or less distinct internal medullary lamina. This extends the whole length of the thalamus, dividing its middle and posterior portion into the medial and the lateral nucleus.
Fia. 694. — HoKizoNTAii Dissection showing the Grey and White Substance op the Telencephalon Below the Corpus Callosum and the Relative Position of the Thalamencephalon. (After Landois and Stirling.)
Funiculus gracilis
Anteriorly the lamina bifurcates into a medial limb, extending to the medial surface of the thalamus, and a lateral limb, extending forward to join the genu of the internal capsule (figs. 695, 700). This bifurcation results in a cup-like sheet of white substance which encloses the anterior nucleus. On the lateral surface of the section, next to the internal capsule, there may usually be distinguished an external medullary lamina, separated from the white substance of the capsule by a reticular layer of mixed white and grey substance.
The anterior nucleus, lying partially encapsulated in the bifurcation of the internal medullary lamina, is somewhat wedge-shaped and points backward between the anterior portions of the lateral and medial nuclei.
It is composed chiefly of large cells, and constitutes the anterior tubercle of the superior aspect. Its principal connection from below is with the nuclei of the mammillary body of the same and opposite sides, and with uninterrupted fibres derived from the columns of the forni.x.
inae, extends posteriorly to include the entire pulvinar.
The pulvinar, as already noted, together with the lateral geniculate body, constitutes the prosencephalic nucleus of termination of the optic tract, and the stratum zonale upon the surface of this nucleus might be called the stratum opticum. The anterior portion of the lateral nucleus receives fibres inferiorly from the red nucleus, from the brachium conjunctivum (cerebellum direct), and some fibres of the medial lemniscus terminate about its cells.
The medial nucleus lies medial to the internal medullary lamina and forms the posterior portion of the lateral wall of the third ventricle. It is shorter than the lateral nucleus, and is less extensively pervaded by fibres.
Fig. 695. — Coronal Section of Prosencephalon through Thalamencephalon at Region OP Corpora Mammillaria. (Seen from in front.) (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
massa intermedia.
In comparative anatomy, the nuclei of the thalamus have been variously subdivided by the different investigators. All the nuclei are connected with the lenticular nucleus by fibres passing between the two through the internal capsule directly, and by fibres curving from below, chiefly from the anterior, lateral and medial nuclei, and passing in the ansa lenticularis.
The cortical connections of the thalamus are abundant. They consist of fibres both to and from the cortex of the different lobes of the hemisphere, the greater part arising in the thalamus and terminating in the cortex. These fibres collect in the internal and external medullary laminae and the stratum zonale; most of them enter the internal capsule and thence radiate to the different parts of the cortex.
They form the so-called peduncles of the thalamus, which have been distinguished both by the Flechsig method of investigation and by the degeneration method. The anterior or frontal peduncle passes from the lateral and anterior part of the thalamus through the frontal portion of the internal capsule, and radiates to the cortex of the frontal lobe. (See fig. 700.) The middle or parietal peduncle passes from the lateral surface of the thalamus through the intermediate part of the internal capsule, and upward to the cortex of the parietal lobe. The posterior or occipital peduncle passes chiefly from the pulvinar, through the occipital portion of the internal capsule, and radiates backward to the occipital lobe by way of the occipito-thalamic (optic) radiation (fig. 699). The inferior peduncle passes from the medial and basal surface of the thalamus (from the anterior and medial nuclei chiefly), turns outward to course beneath the lenticular nucleus, and radiates to the cortex of the temporal lobe and insula. The fibres of this peduncle course chiefly in the ansa lenticularis (fig. 695). Some turn upward in the external capsule to reach the cortex above the insula; others pass upward through the medullary laminae of the lenticular nucleus.
The h3rpothalamic nuclues (fig. 698) , or body of Luys, is the principal nucleus of termination of the medial lemniscus, the great sensory spino-cerebral pathwayl It is a biconvex plate of grey substance situated on the basal aspect of the latera. and anterior nuclei of the thalamus, and between these and the basis of the cerebral
Calcarine fissure
peduncle, or rather the substantia nigra, which is spread upon the dorsal surface of the peduncle, and which, though greatly diminished, extends into the hypothalamic region. The hypothalamic nucleus presents a brownish-pink colour in fresh material, due to pigment in its cells and to its abundant blood capillaries.
It contains the cell-bodies of the neurones of the third order in this pathway, those of the first order being situated in the spinal ganglia, and those of the second order in the nuclei of the fasciculus gracilis and fasciculus cimeatus. It is enclosed by a thin capsule of white substance, some of the fibres of which seem to decussate with those of the opposite side in the floor of the third ventricle, above and just behind the region of the corpora mammiUaria. By far the greater part of the fibres arising from the nucleus join the internal capsule, and through it ascend to
The habenular nucleus and the fasciculus relroflexus of Meynert have been noted in the description of the rhinencephalon. The habenular nucleus, a part of the epithalainus, is a small group of nerve cells situated in the habenular trigone just infero-lateral to the epiphysis. The fibres of the medullary stria of the thalamus (habenula) terminate about its cells. A small bundle of fibres crossing the mid-hne under the epiphysis in the superior aspect of the posterior cerebral commissure is called the commissure of the habenuloe, from the fact that it connects the habenular nuclei of the two sides.
Fig. BOy.' — Oblique Feontal Section through the Brain in the Direction of the Cerebral Peduncles and the Pyramids. (Seen from in front.) (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
The fasciculus retroflexus (Meynerti) is a relatively strong bundle of medullated fibres which runs downward and then turns caudalward from the habenular nucleus toward the inferior portion of the interpeduncular fossa. It has been shown that many, at least, of the fibres of this bundle arise from the cells of the habenular nucleus. In its slightly caudad course, the bundle passes obliquely through the red nucleus, entering the medial superior aspect and making its exit from the ventro-mesial side of the inferior extremity of this nucleus. In the animals in which it has been studied, the bundle ends in the interpeduncular nucleus (ganglion), a group of nerve cells lying in the floor of the interpeduncular fossa at the level of the inferior quadrigemina. In man, the interpeduncular nucleus is not definitely assembled and the bundle seems to disappear in the posterior perforated substance. However, the microscope shows cells dispersed among the fibres of the bundle and these cells probably represent the nucleus.
The white substance of the telencephalon. — A horizontal section through the upper part of the trunk of the corpus callosum will pass above the basal grey substance of the corpus striatum, and, aided by the corpus callosum, each hemisphere in such a section will appear as if consisting of a solid, half-oval mass of white substance, bounded without by the grey layer of the cortex (fig. 672). As
seen at this level, the white substance of each hemisphere is known as the centrum semiovale. Horizontal sections passing below the body of the corpus callosum involve the corpus striatum and thalamus, and the appearance of the white substance is modified accordingly (fig. 694).
In the white substance of the cerebral hemispheres as a whole three main systems of fibres are recognised: — projection fibres, commissural fibres, and association fibres. The projection fibres are those of a more or less vertical course, which pass to and from the cortex of the hemisphere, associating it with the structures below the confines of the hemisphere. The commissural fibres are those of a transverse or horizontal course, which cross the mid-line and functionally connect the two hemispheres with each other. The association fibres are those which neither cross the mid-line nor pass beyond the bounds of the hemisphere in which they arise, but instead associate the different parts of the same hemisphere — lobes with lobes and gyri with gyri. The fibres which associate the cortex with the
nuclei of the corpus striatum must also be classed as association fibres, since these masses of grey substance are a part of the telencephalon, while by definition those which associate the thalamus and hypothalamus with the cortex belong to the projection system. Some of the fibre bundles of the above systems have already been described in connection with the parts with which they are concerned.
The projection fibres of the hemisphere comprise both ascending and descending fibres between the cerebral cortex and structures below the bounds of the hemisphere, i.e., some arise in the structures below and terminate in the cortex; others arise from the cortical cells and terminate in the structures below, including the grey substance of the thalamencephalon, mesencephalon, rhombencephalon, and spinal cord. The projection fibres are given different names in the hemisphere according to their arrangement and the appearances to which they contribute in the dissections. Beginning with the pyramidal fasciculi and the basis of the peduncle, they contribute — (1) to the internal capsule and some to the external capsule and (2) to the corona radiata.
The internal capsule [capsula interna] is a band of white substance, consisting of the ascending fibres from the nuclei of the thalamus, hypothalamus, and corpus striatum, reinforced by the descending fibres from the cortex to these nuclei and by those descending in the cerebral peduncle to terminate in the mesencephalon, rhombencephalon and spinal cord. It is a broad, fan-like mass of fibres, which increases in width from the base of the hemisphere upward, and which is spread between the lenticular nucleus on its lateral aspect and the caudate nucleus and
THE CORONA RADIATA
thalamus on its medial side. To reach the cortex above, the course of its fibres necessarily intersects that of the radiations of the corpus callosum, and thus, together with the corpus callosum, the fan-like bands of the two hemispheres form a capsule containing the thalami, the third ventricle, the caudate nuclei, and the anterior and central portions of the lateral ventricles. In horizontal sections, each internal capsule appears bent at an angle, the genu, which approaches the cavity of the lateral ventricle along the line of the boundary between the thalamus and the caudate nucleus. Along the genu runs the stria terminalis of the thalamus, and through the genu the capsule receives fibres from the internal medullary lamina of the thalamus, from the stratum zonale of the thalamus and from that of the caudate nucleus. At the genu each capsule is separable into two parts: — (1) the anterior (frontal) portion, spreading between the caudate and lenticular nuclei; (2) the posterior (occipital) portion, between the lenticular nucleus and the thalamus (fig. 700.)
Fig. 699. — Coeonal Section THROtroH the Splenium op the Corpus Callosum and the Posterior Cornua op the Lateral Ventricles. (Viewed from behind.) (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
tricle
Medial longitu. The frontal part consists of (1) an anterior segment, carrying chiefly fibres coursing in both directions between the thalamus and the cortex of the frontal lobe, and (2) a posterior segment carrying the frontol-pontUe tract.
The fronto-parietal part may be considered in four segments; — (1) An anterior segment, the genu, carrying fibres from the cortex to the nuclei of the motor cranial nerves; (2) posterior to this is the corticospinal segment for the arm and thorax, descending cortical fibres to the regions of the spinal cord supplying these; (3) next is the corticospinal segment }or the lower extremity; (4) a posterior segment carrying the general sensory path ascending from the hypothalamic nucleus, the infero-lateral part of the thalamus and the red nucleus to the cortex. All the segments of the fronto-parietal part carry in addition, fibres in both directions between the cortex above and the thalamus and the nuclei of the striate body.
The occipital part consists (1) of an anterior segment which carries the temporal and occipital pontile paths, and (2) a posterior segment carrying the visual fibres between the occipital cortex and the nuclei of termination of the optic nerve. This segment also carries the auditory fibres passing between the cortex of the superior temporal gyrus and the regions of termination of the lateral lemniscus. Thus it carries a visual and an auditory path.
The corona radiata. — Above the corpus callosum and laterally joining its radiations, the fibres of the internal capsule are dispersed in all directions. The appearance known in coronal sections of the hemispheres as the corona radiata is produced by the ascending and descending fibres of the internal capsule combined with the radiations of the corpus callosum. The radiations related to the internal
parts of the internal capsule.
The radiation derived from the posterior segment of the occipital part of the internal capsule, the visual path, accumulates into a well-defined band of fibres which passes posteriorly into the occipital lobe, spreading in the lateral wall of the posterior cornu of the lateral ventricle immediately lateral to the tapetum. This band consists for the most part of fibres arising in the pulvinar of the thalamus and
in the lateral geniculate body and going to the visual area of the occipital cortex, and of fibres arising in this cortex to terminate in the thalamus and mesencephalon. Being thus concerned with the optic apparatus, it is known as the occipitothalamic radiation or optic radiation (fig. 699).
spread between the claustrum and the lenticular nucleus.
It owes its appearance as such to the presence of the claustrum. It joins the internal capsule at the upper, posterior, and anterior borders of the putamen, and below the claustrum it is continuous with the general white substance of the temporal lobe. Thus it contributes to an encapsulation of the lenticular nucleus by white substance. Most of the fibres contained in it belong to the association system. Its projection fibres consist of those of the inferior peduncle of the thalamus, which pass from the basal surface of the thalamus and, instead of continuing below to the cortex of the temporal lobe and insula, turn upward, around the lenticular nucleus to the cortex above the insula. Some of these thalamus fibres are known to pass upward through the lamina; of the lenticular nucleus instead of through the external capsule.
(1) The terminal part of the general sensory pathway of the body. The portion of the medial lemniscus which arises in the nuclei of the fasciculus gracilis and cuneatus, of the opposite side, terminates in the hypothalamic nucleus and the inferior portion of the lateral nucleus of the thalamus. The projection fibres given off by the latter nuclei pass chiefly through the posterior segment of the fronto-parietal part of the internal capsule and radiate to and terminate in the somaesthetic area of the cortex, chiefly in the posterior central gyrus. Some few pass outside around the lenticular nucleus, and ascend by way of the external capsule.
(2) The terminal part of the general sensory pathway of the head and neck. The nuclei of termination of the sensory portions of the cranial nerves of the rhombencephalon (except the nuclei of the cochlear nerve) give fibres which course upward in the medial lemniscus (fillet) and reticular substance of the opposite side and terminate in the infero-lateral portions of the thalamus and in the h3rpothalamic nucleus. Thence arise projection fibres which ascend to the somaesthetic area by practically the same route as those of the general sensory system for the body.
' (3) The terminal part of the auditory pathway. The ventral and dorsal nuclei of termination of the cochlear nerve send impulses which, by way of the lateral lemniscus, are distributed to the inferior quadrigeminate body, the medial geniculate body, and the nucleus of the lateral lemniscus of the opposite side. These nuclei send projection fibres through the posterior segment of the fronto-parietal part of the internal capsule, and thence by the temporal portion of the corona radiata to the cortex of the superior temporal gjrrus (auditory area). Probably some of these fibres pass by way of the inferior peduncle of the thalamus. Some of the fibres arising in the nuclei of termination of the vestibular nerve convey impulses which reach the somaesthetic area, but the origin of the terminal portion of this system is uncertain.
(4) The terminal part of the visual pathway. The cells of the pulvinar and the lateral geniculate body, serving as nuclei of termination of the optic tract, give off projection fibres which pass by way of the posterior segment of the occipital portion of the internal capsule and the occipito-thalamic radiation to the cortex of the occipital lobe, chiefly the region about the posterior end of the calcarine fissure — the visual area.
(5) The terminal ascending cerebellar pathway. The fibres of the brachium conjunctivum, after decussating, terminate both in the red nucleus and in the lateral nucleus of the thalamus. Some fibres from the red nucleus become projection fibres direct, others terminate in the medial and anterior portion of the lateral nucleus of the thalamus. From the thalamus the projection fibres of this system pass in the parietal peduncle of the thalamus to the somaesthetic area.
The descending projection fibres arise as outgrowths of the pyramidal cells of the cerebral cortex. Practically all of them cross to the opposite side in their descent to the structures of the brain stem and spinal cord. The majority of them arise near and within the gyri in which the respective ascending fibres terminate. Those transmitting cortical impulses to the cells giving origin to the motor fibres of the cranial and spinal nerves arise chiefly from the giant pyramidal cells of the precentral (anterior central) gyrus, the paracentral lobule and the posterior ends of the superior, middle, and inferior frontal gyri. These latter occupy nearly three-fourths (the anterior three segments) of the fronto-parietal part of the internal capsule and the middle three-fifths of the basis of the cerebral peduncle, and are usually called 'pyramidal fibres (fig. 700).
The principal descending projection fibres may be grouped as follows:
(1) The pyramidal fibres to the spinal cord (cortico-spinal or pyramidal fascicuh proper). These arise from the giant pyramidal cells of the upper two-thirds of the precentral gyrus, the anterior portion of the paracentral lobule and the posterior third of the superior frontal gyrus. Those for the lumbo-sacral region of the spinal cord arise nearest the supero-mesial border of the cerebral hemisphere. The tract descends through the two middle segments of the fronto-parietal part of the internal capsule. Those carrying cortical impulses for the muscles of the arm and shoulder course in the segment anterior to the course of those for the muscles of the leg. Both continue through the cerebral peduncles and the pons and through the pyramids of the medulla, and then decussate, passing down the spinal cord to terminate about the ventral horn ccUs (the origin of the motor nerve roots) of the opposite side.
(2) The pyramidal fibres to the nuclei of origin of the motor cranial nerves arise from the pyramidal cells in the inferior third of the precentral gyrus, the posterior end of the inferior frontal gyrus, the opercular margin of the posterior central gyrus, and probably some (for eye movements) in the posterior end of the middle frontal gyrus. The locality of the origin of the pyramidal fibres terminating in the nuclei of the facial and hypoglossal nerves only has been determined with certainty. The general tract passes in the genu of the internal capsule, through the cerebral peduncle, and, gradually decussating along the brain stem, terminates in the nuclei of the motor cranial nerves of the opposite side.
(3) The frontal pontile path (Arnold's bundle) arises in the cortex of the frontal lobe, anterior to the precentral gyrus, descends through the frontal part of the corona radiata and posterior segment of the frontal portion of the internal capsule into the fronto-mesial portion of the cerebral peduncle, and terminates in the nuclei of the pons.
(4) The temporal pontile path (Turk's bundle) arises in the cortex of the superior and middle temporal gyri, passes through the posterior segment of the occipital part of the internal capsule, enters the cerebral peduncle postero-lateral to its pyramidal portion, and terminates in the nuclei of the pons. An occipito-pontile path is described as arising in the occipital cortex and joining the temporal pontile path in the internal capsule to pass to the nuclei of the pons.
(5) The occipito-mesencephalic path (Flechsig's secondary optic radiation) arises in the cortex of the visual area of the occipital lobe (cuneus and about the calcarine fissure), passes forward through the occipito-thalamic radiation, downward in the posterior segment of the occipital portion of the internal capsule, and terminates in the nucleus of the superior quadrigeminate body and the lateral geniculate body. It is probable that some of its fibres terminate directly in the nuclei of the eye-moving nerves.
(6) Those fibres of the fornix which arise in the hippocampus and terminate in the corpus mammiUare or pass through it to the anterior nucleus of the thalamus of the same and opposite side (mammiUo-thalamic fasciculus) or pass into the mescencephalon and probably to structures lower down.
The commissural system of fibres. — ^The commisstiral fibres of the telencephalon serve to connect or associate the functional activities of one hemisphere with those of the other. They consist of three groups: — The corpus callosum, the anterior commissure and the hippocampal commissure.
(1) The corpus callosum, the great commissure of the brain. A general description of this with the medial and lateral striae running over it has aheady been given. It is a thick band of white substance, about 10 cm. wide, which crosses between the two hemispheres at the bottom of the longitudinal fissure. Its shape is such that in its medial transverse section its parts are given the names splenium, body, genu, and rostrum (figs. 667 and 679). Its lower surface is medially joined to the fornix, in part by the septum peUucidum and in part directly. Laterally it is the tapetum of the roof of the lateral ventricle of either side. The majority of its fibres arise from the cortical cells of the two hemispheres, and terminate in the cortex of the side opposite that of their origin. In dissections, its fibres are seen to radiate toward all parts of the cortex — the radiation of the corpus callosum. These radiations may be divided into frontal, parietal, temporal and occipital parts. The occipital parts curve posteriorly in two strong bands from the splenium into the occipital lobes, producing the figure known as the forceps major. Anteriorly, the frontal parts are two similar but lesser bands which curve from the genu forward into the frontal lobe, producing the forceps minor.
(2) The anterior commissure has been described in connection with the rhinencephalon. In addition to the ohactory fibres coursing through it from the olfactory bulb and parolfactory area of one hemisphere to the uncus of the opposite hemisphere, its greater part consists of fibres which arise in the cortex of the temporal lobe, the uncus chiefly, of one side and terminate in that of the opposite side. It crosses in the substance of the anterior boundary of the third ventricle, and through the inferior portions of the lenticular nuclei, and can be seen only in dissections (figs. 684, 693). It is a relatively small, round bundle, and its mid-portion between its terminal radiations presents a somewhat twisted appearance.
(3) The hippocampal commissure (transverse fornix) belongs wholly to the limbic lobe (rhinencephalon), and has been described there. It connects the hippocampal gyri of the two sides, and crosses the mid-Mne under and usually adhering to the under surface of the splenium of the corpus callosum. Crossing the body of the fornix, it thins anteriorly and ceases in the posterior angle of the septum peUucidum.
With these three commissures of the telencephalon, the three other commissures of the prosencephalon should be called to mind. The inferior cerebral commissure (Gudden's commissure), while occurring in the optic chiasma and allotted by position to the telencephalon, really belongs to the diencephalon since it connects with each other the medial geniculate bodies of the two sides. The supra-mammillary commissure, connecting the nuclei of the mammiUary bodies of the two sides, is allotted to the diencephalon. The posterior cerebral commissure, situated just below the stalk of the epiphysis, belongs to both the diencephalon and mesencephalon. Its superior part, the habenular commissure, connecting the two nuclei of the habenulae, belongs wholly to the diencephalon. In its inferior part, the fibres arising in the thalamus of one side and terminating in that of the other side belong likewise to the diencephalon, but those passing between the superior quadrigeminate bodies of the two sides and between the so-called nuclei of the medial longitudinal fasciculi belong to the mesencephalon.
The association system of the hemisphere. — The possibilities for association bundles connecting the different parts of the same hemisphere with each other are innumerable, and a large number are recognised. They serve for the distribution or diffusion of impulses brought in from the exterior by the ascending projection system, and it is by means of them that the different areas of the cortex may function in harmony and coordination. Most of the association bundles are supposed to contain fibres coursing in both directions. Several of them have already been described in company with the grey masses with which they are concerned. They may be summarised as follows (see figs. 683, 701 and 702) : — ■
(1) Those of short course, the fibrse propriae, which associate contiguous gyri with each other. These arise from the ceUs of a gyrus and loop around the bottoms of the sulci, continually receiving and losing fibres in the cortex they associate. The stripes of BaiUarger within the cortical layer might be included among the short association bundles.
ASSOCIATION FIBRES
extends from the anterior perforated substance and the subcallosal gyrus around the genu of the corpus callosum, then, under cover of the gyrus cinguU and around the splenium, and thence downward and forward in the hippocampal gyrus to the uncus. It is chiefly an aggregation of fibres of short course — fibres which associate neighbouring portions of the cortical substance
Inferior longitudinal fasciculus
beneath which they course, and which, by continually overlapping each other, form the bundle. (3) The uncinate fasciculus is a hook-shaped bundle which associates the uncus and anterior portion of the temporal lobe with the olfactory bulb, parolfactory area and anterior perforated substance and perhaps the frontal pole with the orbital gyri. Its shape is due to its having to curve medialward around the stem of the lateral cerebral fissure.
(4) The superior longitudinal fasciculus is the longest of the association paths, and associates the frontal, occipital, and temporal lobes. From the frontal lobe it passes laterally in the frontal and parietal operculum, transverse to the radiations of the corpus callosum and the lower part of the corona radiata, and above the insula to the region of the posterior end of the lateral fissure, and thence it curves downward and forward to the cortex of the temporal lobe. Some of its fibres extend to the cortex of the temporal pole. The occipital portion consists of a loose bundle given off from the region of the downward curve, which radiates thence to the occipital cortex.
(5) The inferior longitudinal fasciculus associates the temporal and occipital lobes and extends along the whole length of these lobes parallel with their tentorial surfaces. Posteriorly it courses lateral to the lower part of the oceipito-thalamic radiation, from which it differs by
and the cuneus with the temporal pole.
(6) The medial and lateral longitudinal striae of the upper surface of the corpus caUosum may be considered among the association pathways, since most of their fibres associate the grey substance of the hippocampal gyrus with the subcallosal gyrus and the anterior perforated substance of the same hemisphere. Their significance as parts of the rhinencephalon has already been given.
(7) Likewise the longitudinal fibres in the stria terminalis of the thalamus (taenia semicircularis) may be considered among the association pathways, since these connect the amygdaloid nucleus with the anterior perforated substance.
(8) The numerous fibres passing in both directions between the cerebral cortex and the nuclei of the corpus striatum belong to the association system. These do not form a definite bundle, but, instead, contribute appreciably to the corona radiata. However, a pathway described as the occipito-frontal fasciculus probably consists largely of the more sagittally running fibres of this nature. The existence of this fasciculus has been noted in degenerations and in cases of arrested development of the corpus callosum. Its fibres are described as contributing greatly to the tapetum, and as coursing beneath the corpus callosum immediately
FUNCTIONAL AREAS OF CORTEX 893
next to the ependyma of the lateral ventricle. As a mass, they appear in intimate connection with the caudate nucleus, and are spread toward both the frontal and the occipital lobes (chiefly the latter), in the mesial part of the corona radiata of those lobes. It is described as also containing fibres in both directions associating the occipital with the temporal lobe. Vertical association fibres pass through the caudate and lenticular nuclei between the cortex above and that of the temporal lobe below.
(9) Since the olfactory bulb is a part of the hemisphere proper, the olfactory tract may be considered an association pathway connecting the olfactory bulb with the parolfactory area, the subcallosal gyrus, the anterior perforated substance, and the uncus. As already shown, a portion of the fibres of the tract belongs to the commissural system.
THE FUNCTIONAL AREAS OF THE CEREBRAL CORTEX
The definitely known areas of specific function of the human cerebral cortex are relatively small. They comprise but little more than a third of the area of the entire hemisphere. They are — (1) the general sensory-motor or somaisthetic area, and (2) the areas for the organs of special sense. They represent portions of the cortex in which terminate sensory or ascending projection fibres bearing impulses from the given peripheral structures, and in which arise motor or descending projection fibres bearing impulses in response.
Knowledge of the location of the areas has been obtained — (1) by the Flechsig method of investigation, and to a considerable extent by Flechsig himself; (2) from clinico-pathological observations, largely studies of the phenomena resulting from brain tumors and traumatic lesions; (3) by experimental excitation of the cortex of monkeys and apes, the resulting phenomena being correlated with the anatomical findings and compared with the observations upon the human brain. The remaining larger and less known areas of the cortex are referred to as 'association centres' or areas of the 'higher psychic activities.'
In development, the sensory fibres to the specific areas acquire their medullary sheaths first, before birth, and then the respective motor fibres from each become medullated. It ia not till a month after birth that the association centres show medullation and therefore acquire active functional connection with the specific areas.
In defining an area it is not claimed that all the fibres bearing a given type of impulse terminate in that area, nor that all the motor fibres leading to the given reaction originate in the area. It can only be said that of the fibres concerned in a given group of reactions, more terminate and arise in the areas cited than in any other areas of the cortex. The corresponding motor fibres arise both in the region of the termination of the sensory fibres (sensory area) and also in a zone (motor area) either partially surrounding or bordering upon a part of the region of termination.
(1) The somaesthetic (sensory-motor) area, the area of general sensibility, and the area in which arise the larger part of the cerebral motor or pyramidal fibres for the cortical control of the general muscular system. As is to be expected, it is the largest of the specific areas. It includes the anterior central gyrus, posterior central gyrus, the posterior ends of the superior, middle, and inferior frontal gyri, the paracentral lobules, and the immediately adjacent part of the gyrus cinguli. The ascending or sensory fibres are found to terminate most abundantly in the part posterior to the central sulcus (Rolandi), the posterior central gyrus being the special area of cutaneous sensibility, and the adjacent anterior ends of the horizontal parietal gyri have been designated as the area of 'muscular sense.' Both these areas are carried over upon the medial surface to involve the lower part of the paracentral lobule and a part of the gyrus cinguli. The anterior central gyrus gives origin to relatively more motor fibres than the other portions of the somffisthetic area. In distribution, the muscles furthest away from the cortex are innervated from the most superior part of the area, the leg area being in the supero-mesial border of the hemisphere, while that from the head is in the anterior and inferior part of the area (fig. 703). The muscles of mastication and the laryngeal muscles are controlled from the fronto-parietal operculum. Broca's convolution, the opercular portion and part of the triangular portion of the inferior frontal gyrus, of the left hemisphere, constitutes the especial motor area of speech, and Mills has extended this area to include the supero-anterior portion of the insula below. The various authorities differ considerably as to the exact locations of many of the areas for the cortical control of given sets of muscles. Further observations must be skillfully made tor localisation of areas of the human cortex in detail and further correlations must be determined between the experiments upon the cortex of anthropoid apes and the functions of that of man. The accompanying diagrams are compiled from several of the diagrams more usually given and must be considered as only approximately correct.
(2) The visual area. — The especial sensory portion of this area is that immediately bordering upon either side of the posterior part of the calcarine fissure. The entire area, motor and sensory overlapping each other, includes the whole of the cuneus. The motor visual area proper is described as the more peripheral portion of the entire area. In addition, an area producing eye movements is described as situated in the posterior end of the middle frontal gyrus.
(3) The auditory (cochlear) area comprises the middle third of the superior temporal gyrus and the transverse temporal gyri of the temporal operculum. The motor portion of this area hes in its inferior border. The fibres arising in the area course downward ia the temporal pontile path to the motor nuclei of the medulla.
(4) The olfactory area consists of the olfactory trigone, the parolfactory area, the subcallosal gyrus, part of the anterior perforated substance, the hippocampal gyrus (especiaUj' the uncus), and the callosal half of the gyrus cinguli. Its motor or efferent area lies chiefly in the hippocampal g3T.'us, the fibres from which pass out from the telencephalon by way of the fornix and cingulum.
(6) The assocaition areas. — The relatively large areas allotted at present to the so-called higher psychic activities are indicated in fig. 703. The great relative extent of these is one of the characteristics of the human brain. They probably merely represent the portions of the cortex of which httle is known, and may eventually be subdivided into more specific areas. They are considered to be connected with the structures below by fewer projection fibres than are the recognised areas named above, while, on the other hand, they are rich in association fibres. By means of the latter they are in intimate connection with the specific areas and have abundant means of correlating and exercising a controlhng influence upon the functions of these areas. According to Flechsig, they consist of — (1) a parietal association area, comprising that part of the parietal cortex between the somaesthetic area and the visual area; (2) an occipitotemporal association area, including the unspecified portions of the temporal lobe and the adjoining portion of the occipital lobe not included in the visual area; (3) a frontal association area, including all the frontal lobe anterior to the somesthetic and olfactory area. In the folds of the inferior parietal lobule of the parietal association area such intellectual activities as the optic discrimination of words, letters, numbers, and objects generally are supposed to
Observations of symptoms and the position of lesions accompanying them have made it possible to arrive at some trustworthy conclusions regarding the cortical areas controlling speech. Broca announced in 1861 that the inferior frontal gjTus of the left hemisphere was peculiarly concerned with speech. This area was later confined to the posterior end or opercular portion of this gyrus and the name "Broca's Convolution" was given it. It is now known that Broca's convolution and the adjacent portion of the triangular part of the inferior frontal gyrus as well comprise the motor area or emissive speech area — the area especially devoted to the control of that coordinated action of the muscles concerned which makes possible articulate speech. Patients in whom this area is impaired are unable to give utterance to words though they may understand them both written and spoken, and though they may give utterance to sound. This inability is known as motor aphasia. Results of observed lesions have further shown that the area in which the auditory images of words are retained (word memories) comprises the posterior end of the superior temporal gyrus and the adjoining portion of the supramarginal gyrus. Injury to this area is accompanied by inability to recognise spoken words although the patient hears them and may recognise and understand written words, a phenomenon known as "word-deafness" or sensory aphasia. This area may be considered as continuous with the superior portion of the posterior end of the middle temporal gyrus which has been suggested as the area of "word-understanding," or "lalognosis." On the other hand, the area in which visual images of words are retained is located as the angular gyrus. Injury to this results in an inability to recognise printed or written words although the patient
may hear, understand and speak them. This is called "word-Uindness." This area is nearest the special area of vision on the one hand and on the other hand, is continuous into the area to which word-understanding is attributed. For purposes of writing, it must be associated with the motor area for the muscles of the hand in the precentral gyrus.
In the following summary the arabic numerals indicate paragraphs in which are mentioned the nuclei or ganglia containing the cell-bodies of the neurones interposed in the chains; the small letters indicate the different names given to the different levels of the pathways through which their fibres run. For detailed descriptions of either nuclei or pathways see pages describing them. Only the more common neurone chains are followed here.
(/') Lateral cerebro-spinal fasciculus (crossed pyramidal tract), (e^) Ventral cerebro-spinal fasciculus (direct or uncrossed pyramidal tract). (P) Gradual decussation of latter in cervical and upper thoracic regions of spinal cord.
muscle apparently do not decussate but terminate in the nuclei of the same side.
(2) The efferent nucleus of the glosso-palatine (salivatory nucleus) and the dorsal efferent nucleus of the vagus give rise to visceral efferent fibres, i.e., carry impulses destined for smooth muscle and glands by way of sympathetic neurones. The same is true for the supero-median part of the nucleus of the oculomotor.
motor nerves. Fibres to the more distant nuclei pass to them by way of the medial longitudinal fasciculus. Instead of terminating in the motor nuclei directly, the sensory fibres are usually interrupted by a third or intermediate neurone interposed in the chain. The vagus and glosso-pharyngcus are connected by way of the solitary fasciculus and its nucleus with the structures below their level of entrance, even with the ventral horn cells of the upper segments of the cervical cord, and through these with the muscles of respiration.
(6) Collaterals and descendiag branches of bifurcation of dorsal root fibres in spinal cord, chiefly those conveying impulses of muscle-sense. 2x. Dorsal nucleus (Clarke's column).
4. Red nucleus and ventral portion of lateral nucleus of thalamus. Most fibres of the
brachium conjunctivum terminate in the red nucleus; many merely give off collaterals to it in passing to their termination in the thalamus. Most of the ascending fibres arising in the red nucleus also terminate in the ventral part of the thalamus; some ascend to the cerebral cortex direct.
pontile path which passes under the lenticular nucleus into anterior segment of occipital portion of internal capsule and lateral part of cerebral peduncle to nuclei of pons of opposite side. This path is joined in the internal capsule by a small occipitopontile path.
4. Cells of nuclei of pons send fibres by way of brachium pontis (middle cerebeOar peduncle) to cortex of cerebellar hemisphere, of side opposite to that of the origin of the cei-ebral fibres making synapses with the cells of the pons.
C. Descending cerebellospinal paths.
1. From cells of nucleus fastigii of same and opposite sides and probably from other nuclei of cerebellum arise fibres which terminate in the nuclei of termination of the vestibular nerve and these send fibres into the intermediate and anterior marginal fasciculi of spinal cord (fig. 619), and thence to the cells of the anterior horn.
2. Probably connected with the cerebellum is the pathway arising in the red nucleus of the opposite side and descending in the rubro-spinal tract of the lateral funiculus of the spinal cord (fig. 619). The rubro-spinal tract decussates in the ventral portion of the tegmentum of the mesencephalon and is said to pass through the medulla oblongata in the medial longitudinal fasciculus. It must be noted here that some fibres arising in the cortex of the frontal lobe terminate in the red nucleus.
(d) The nuclei receive fibres from the grey substance of the vermis. It is probable that all the nuclei of termination give off fibres bearing ascending impulses which ultimately reach the somresthetic area, but the course pursued and neurones involved in such a chain are uncertain.
(o) Striae medullares arise from dorsal nucleus and pass around outer side of restiform body (acoustic tubercle), then medianward under ependyma of floor of fourth ventricle to mid-line, then ventralward into tegmentum, where they decussate and join trapezoid body and lateral lemniscus of opposite side.
(6) Fibres arising in ventral nucleus pass ventraDy medianward and some terminate in the superior ohvary nucleus of same side; others pass by way of trapezoid body and lateral lemniscus to terminate in superior olivary nucleus, nucleus of lateral lemniscus, medial geniculate body and nucleus of inferior quadrigeminate body of the opposite side.
3. Nuclei of superior olives of both sides and nucleus of lateral lemniscus send fibres by way of lateral lemniscus to inferior quadrigeminate body and through inferior brachium to medial geniculate body, and some may pass uninterrupted to the cortex of the temporal lobe.
4. Fibres from medial geniculate body and probably from nucleus of inferior quadrigeminate body pass into internal capsule and through temporal part of corona radiata to middle third of superior temporal gyrus and adjacent portions (auditory area).
6. From strife medullares and from superior ohvary nucleus (peduncle of superior olive) arise fibres which terminate in nucleus of abducens or pass by way of the medial longitudinal fasciculus to other motor nuclei of cranial nerves. It is probable that fibres from the auditory area of the cerebral cortex are also distributed to nuclei of the cranial nerves.
. Oplic impulses.
1. 'Bipolar' cells of retina with short (peripheral) processes to layer of rods and cones (neuro-epithehum) and short centrally directed processes to ganglion-cell layer of retina (nucleus of termination).
(o) Fibres from nucleus of superior quadrigeminate body pass ventrally, to nuclei of origin of oculomotor and trochlear nerves and to medial longitudinal fasciculus of same and opposite sides, and from it are distributed to nucleus of origin, of abducens.
CORP. GEN. M
4. Cells of visual area of cortex send fibres through occipito-thalamic radiation and occipital portion of internal capsule to nucleus of superior quadrigeminate body (oocipito-mesencephalic fasciculus), and thence, probably interrupted by cells of this nucleus, to nuclei of eye-muscle nerves.
5. Cells of nucleus of superior quadrigeminate body and pulvinar send fibres by way of medial longitudinal iasciculus into lateral and ventral funicuU of spinal cord (see fig. 619), chiefly of the opposite side. Fibres from the quadrigeminate body cross mid-line chiefly in decussation of 'optic-acoustic reflex path' (fig. 662).
1. Peripheral processes of spinal gangUon cells terminating in the skin and central processes of same entering by way of dorsal roots of cervical nerves to bifurcate in spinal cord and give terminal twigs about — •
1. Cells of the nuclei of termination of the cochlear nerve and superior olive send fibres by way of the medial longitudinal fasciculus (some to this by way of the peduncle of the superior olive) to the nuclei of origin of the eye-moving nerves.
2. The same nuclei of the cochlear nerve send axones by way of the lateral lemniscus to terminate in the superior quadrigeminate body and thence may be sent impulses which are distributed to the nuclei of the eye-moving nerves.
IX. Principal Conduction Paths op Olfactoky Apparatus
1. Bipolar cells of olfactory region of nasal epithelium send short (peripheral) processes toward surface of nasal cavity and centrally directed processes, the olfactory nerve, through lamina cribrosa of ethmoid bone into olfactory bulb (glomerular layer).
(6) Medial olfactory stria through which fibres pass — (1) into parolfactory area (Broca's area); (2) into subcallosal gyrus; and (3) by way of anterior cerebral commissure to olfactory bulb and uncus of hippocampal gyrus of opposite side.
(c) The fornix, which, interrupted in part in the nuclei of the corpus mammUlare, conveys impulses — (1) to the anterior nucleus of thalamus of the same (chiefly) and opposite sides (mammillo-thalamic fasciculus), and (2) into the mesencephalon and substantia nigra (mammillo-mesencephalic fasciculus), and by way of this tract probably to the nuclei of the mesencephalon and medulla oblongata.
The Relations of the Brain to the Walls of the Ceanial Cavity
The precise methods by which the exact positions of the most important fissures, sulci, gyri, and areas can be ascertained and mapped out on the surface of the head in the living subject are fully described in Section XIII. Here, only a very general survey of the relations of the brain to the cranial bones is given and from a purely anatomical standpoint.
The parts of the brain which lie in closest relation with the walls of the cranial cavity are the olfactory bulb and tract, the basal and lateral surfaces of the cerebral hemispheres, the inferior surfaces of the lateral lobes of the cerebellum, the ventral surfaces of the medulla and pons, and the hypophysis.
Certain of these portions of the brain lie in relation with the basi-cranial axis, that is, with the basi-oGcipital, the basi-sphenoid, and the ethmoid bones, while others are associated with the sides and vault of the cranial cavity. Considering the former portions first, the ventral surface of the medulla oblongata, which is formed by the pyramids, lies upon the upper surface of the basi-occipital bone. More superiorly the ventral surface of the pons rests upon the basi-
sphenoid, from which it is partly separated by the basilar artery and the pair of abducens nerves. In front of the dorsum sella3 the hypophysis (pituitary body) is lodged in the hypophyseal fossa. Still further forward the olfactory tracts he in grooves on the upper surface of the presphenoid section of the sphenoid bone; and in front of the sphenoid the olfactory bulbs rest upon the cribriform plates of the ethmoid.
Posterior and lateral to the posterior part of the foramen magnum the lateral lobes of the cerebellum are in relation with the cranial wall, resting upon the lower parts of the supraoccipital and the posterior parts of the ex-occipital portions of the occipital bone, while anteriorly each lobe is in relation with the inner surface of the mastoid process and the posterior surface of the petrous portion of the temporal bone. The area of the skull wall which is in close relationship with the cerebellar hemispheres may be indicated, on the external surface of the skull, by a line which commences at the inferior part of the external occipital protuberance and thence runs upward and lateralward. It crosses the superior nuchal line a httle beyond its centre, and, continuing in the same direction, crosses the inferior part of the lambdoid suture and reaches a
Eoint directly above the asterion (the meeting-point of the occipital, temporal, and parietal ones) ; thence it descends, just in front of the occipito-mastoid suture, to the tip of the mastoid process, and there turns medialward to its termination at the margin of the foramen magnum, immediately behind the posterior end of the oociptal condyle.
by the orbital surface of the frontal lobe, rests upon the upper surfaces of the orbital plate of the frontal bone and the lesser wing of the sphenoid. It is, therefore, in close relation with the upper wall of the orbital cavity. The posterior part, behind the stem of the lateral fissure, begins with the anterior portion of the temporal lobe, including its pole. The pole itself projects against the orbital plate of the great wing of the sphenoid bone, and it is in relationship with the posterior part of the lateral wall of the orbit. The basal surface of the hemisphere, behind the pole of the temporal lobe is in contact with the upper surfaces of the great wing of the sphenoid and the petrous part of the temporal bone.
The convex surfaces of the cerebral hemispheres have the most extensive relationships with the cranial wall, and it is more especially to these surfaces that the surgeon turns his attention. The general area in which the convex surface of each cerebral hemisphere is in relation with the skuU bones is readily indicated by a series of lines which correspond with the positions of its superciliary, infero-lateral, and supero-mesial borders.
The line marking the superciliary margin of the hemisphere commences at the nasion (the mid-point of the fronto-nasal suture) ; it passes lateralward above the superciliary ridge, crosses the temporal ridge, then, turning posteriorly in the temporal fossa, it reaches the parietosphenoidal suture, and continues backward along it to its posterior extremity.
The line marking out the infero-lateral border commences at the posterior end of the parietosphenoidal suture, whence it passes downward, in front of the spheno-squamous suture, to the infra-temporal ci-est (pterygoid ridge) ; there it turns posteriorly and, running parallel with and mesial to the zygomatic arch, it crosses the root of the zygoma, and, ascending slightly, it passes above the external auditory meatus. Continuing backward with an incliriation upward it reaches a point immediately above the asterion; thence it descends, and, crossing the inferior part of the lambdoid suture and the superior nuchal line, it passes medialward to the inferior part of the external occipital protuberance.
The supero-mesial border of the hemisphere is defined by a line which runs from the nasion to the inion. This line should be drawn about 5 mm. lateral to the sagittal suture, because the mesial area is occupied by the superior sagittal sinus, and it should be further away from the middle line on the right than on the left side, because the sinus tends to he more to the right side.
The area of the skull wall enclosed by the three lines which mark the positions of the superciliary, infero-lateral, and the supero-mesial borders of the cerebral hemisphere is formed by the vertical plate of the frontal bone, the parietal bone, the great wing of the sphenoid, the squamous part of the temporal, and the upper section of the supra-occipital segment of the occipital bone. It covers the outer surfaces of the frontal, parietal, temporal, and occipital lobes of the cerebrum and the fissures and sulci which bound and mark them.
In every consideration of the topographical relations of the cerebral g3Ti to the walls of the cranial cavity it must be borne in mind that the conditions are not constant, and that, therefore, the relations are variable. The three main factors upon which this variability depends are age, sex, and the shape of the skull. As examples of the variations which occur it may be mentioned that the lateral cerebral fissure is relatively higher in the child than in the adult (compare figs. 711 and 712). The supero-mesial end of the central sulcus is further away from the coronal suture in the female and in the child than in the adult male, and in dolichocephalic than in
braohycephalic heads. The angle formed between the Hne of the central fissure and the midsagittal plane, which averages about 68° in the adult, is more acute in dolichocephalic heads, and the external part of the parieto-occipital fissure is further forward in the child, and possibly in the female, than it is in the adult male.
The position of the posterior horizontal limb of the lateral fissure varies even in the adult. Its posterior part is always under cover of the parietal bone, and it terminates either in front of or inferior to the parietal eminence, but the anterior part may be above, parallel with, or inferior to the squamo-parietal suture. In the adult the anterior part of the fissure runs upward and backward from the posterior end of the spheno-parietal suture along the anterior part of the squamo-parietal suture to its highest point; thence it continues in the same direction beneath the parietal bone toward the lambda, terminating either in front of or below the parietal eminence. In the child, however, the fissure is considerably above the hne of the squamo-parietal suture (fig. 712), which it gradually approaches, attaining its adult position about the ninth year. This change of position, which occurs during the first nine years, is due partly to the ascent of the sutural hne and partly to the descent of the fissure on the surface of the brain.
The frontal bone always covers the superior, middle, and inferior frontal gyri, except their posterior extremities, which are beneath the parietal bone (fig. 711). The ascending limb (ramus anterior ascendens) of the lateral fissure, which cuts into the posterior part of the inferior frontal gyrus, runs parallel with and under cover of the lower part of the coronal suture, or immediately in front of it, and the anterior horizontal hmb is parallel with and beneath the upper margin of the great wing of the sphenoid.
The parietal bone is in relation with the convex surfaces of four lobes of the brain. Speaking very generally, it may be said that the anterior third covers the posterior part of the frontal lobe, including the anterior central gyrus, and the posterior ends of the superior, middle, and inferior frontal gyri and the precentral sulcus. The posterior two-thirds of the bone are superficial to the perietal lobe, the posterior part of the temporal lobe, the anterior part of the occipital lobe, the posterior part of the horizontal limb of the lateral fissure, the superior and inferior parts of the post-central sulcus, the interparietal sulcus, the posterior sections of the superior and middle temporal sulci, and the external part of the parieto-occipital fissure. The central sulcus is beneath the parietal bone at the junction of its middle and anterior thirds (fig. 711).
In the adult, the upper end of the central sulcus is situated at about 55 per cent, of the whole length of the naso-inionic hne posterior to the nasion. It is about 4 or 5 cm. from the coronal suture. The inferior end of the sulcus, which extends to near the posterior horizontal limb of the lateral fissure, lies beneath the point of intersection of the auriculo-bregmatic line with a hne drawn from the stephanion (the point where the temporal ridge cuts the coronal suture) to the asterion. This point is about 46 per cent, of the horizontal arc measured from the glabella to the inion.
The superior end of the parieto-occipital fissure usually lies about 6 mm. in front of the lambda, and the course of the fissure may be indicated by a line drawn from 5 mm. in front of the lambda to a point immediately above the asterion, and, as the latter point corresponds with the pre-occipital notch on the infero-lateral border of the hemisphere, the line in question will indicate the adjacent margins of the parietal, temporal, and occipital lobes.
The occipital bone is in close relation with the cerebellum, as already pointed out, but it also covers the posterior part of the lateral surface of the occipital lobe of the cerebral hemisphere. The great wing of the sphenoid covers the outer surface of the pole of the temporal lobe, and the squamous part of the temporal bone covers the anterior parts of the superior, middle, and inferior temporal gyri and the sulci which separate them.
The double origin of the continuous arterial system of the brain given by the confluence of the two vertebral arteries and the two internal carotid arteries, together with the description of the general distribution of the different cerebral, mesencephalic, and cerebellar arteries into which the system is divided, and the origin and course of the corresponding veins, are fuUy dealt with in Section V. Here attention may be called briefly to the abundant and systematic internal distribution of the terminal branches of the system and their intimate arrangement for the actual nourishment of the nervous tissues within.
The general plan of the blood supply for the entire encephalon may be summarised as follows:— (1) At their origin the different arteries are so connected, directly or indirectly, on the base of the encephalon, that the blood approaching the brain by way of the vertebral and internal carotid arteries is practically a common supply for all the arteries of the encephalon, and a given part of it may possibly pass mto any one of them. (2) In the pia mater of each gross division of the encephalon the different arteries again become coimected with each other in a superficial, freely anastomosing plexus, contmuous thi'oughout. (3) From this plexus of the surface, naturally composed in part of the trunks of the different arteries themselves, arise branches which enter directly into the nervous substance and which break up into twigs that are terminal; i. e., twigs that do not anastomose with each other. (4) The arterial capillary system arising from the terminal twigs passes over into venous capillaries which converge to form corresponding venous twigs which in their turn pass to the sm-face and join in forming a peripheral, anastomosing venous plexus superimposed upon the similar arterial plexus. (5) From this venous plexus arise the different veins of the encephalon which may or may not accompany the arteries for a short distance, and which finaUy empty into the sinuses in the cranial dura mater. These, likewise confluent, empty into the internal jugular veins. The chorioid plexuses of the ventricles of the brain are modifications of the general anastomosing peripheral plexuses. The chorioid plexuses of the lateral and third ventricles are derived largely from branches of the chorioid arteries, which arises separately from the internal carotid artery.
The blood supply of the cerebrum may best be taken as an illustration of the general plan of the blood-vascular system of the encephalon. The terminal or internal branches of the surface plexus, derived from the posterior, middle, and anterior cerebral arteries, are arranged into two groups, a central or ganglionic and a cortical group. The central branches themselves form four groups in each hemisphere: —
(1) The antero-mesial group consists of terminal branches from the plexus of the domain of the anterior cerebral artery, which pass through the medial part of the anterior perforated substance and supply the head of the caudate nucleus, the septum peUucidum, the columns of the fornix, and the lamina terminaUs.
(2) The antero-lateral group consists of terminal branches from the domain of the middle cerebral artery. These pierce the anterior perforated substance in two sub-groups — (a) the internal and (6) the external striate arteries (fig. 713). The internal striate arteries pass thi'ough the segments of the globus paUidus of the lenticular nucleus and through the internal capsule, to both of which they give branches, and they terminate in the caudate nucleus and thalamus. The external striate arteries are larger and more numerous. They pass upward between the external capsule and the putameu, and then through or around the upper part of the putamen into the internal capsule, where they form two groups, the lenticulo-lhalamic and the lenticulo-caudate groups. The former terminate in the thalamus and the latter in the caudate nucleus. On account of its larger size at its origin and its direct linear continuation with the internal carotid, emboU {thrombi) pass more frequently into the middle cerebral artery
than into the anterior cerebral artery. One of the lenticulo-caudate arteries which is larger and longer than the others and which is a direct branch from the middle cerebral artery has been called the 'artery of cerebral hemorrhage' (Charcot), on account of the greater frequency with which it is ruptured.
(3) The postero-medial central arteries are terminal branches of the posterior cerebral artery. They also enter the anterior perforated substance, but supply the floor of the third ventricle, the posterior part of the thalamus, and the hypothalamic region.
(4) The postero-lateral group are also terminal branches of the posterior cerebral artery. They supply the posterior part of the internal capsule, the pulvinar of the thalamus, the geniculate bodies, the corpora quadrigemina and their brachia, the epiphysis, and the cerebral pedunces.
The cortical group of the cerebral arteries arise from the anastomosing plexus in the pia mater of the cortical surfaces of the hemisphere. They pass into the cortical substance both from the summits of the gyri and from the walls of the sulci. They consist of short, medium, and long branches, and pass at right angles into the gyri. The short branches terminate in the cortical substance; the medium branches supply the more adjacent white substance, and the longer branches pass more deeply into the general medullary centre of the hemisphere.
The blood-vessels of the mesencephalon, in addition to the supply derived from the posterolateral group of central arteries, include the vessels of the quadrigeminate bodies and those of the cerebral peduncles. The arteries of the quadrigeminate bodies are usually six in number, three for each side — the superior, middle, and inferior quadrigeminate arteries. The superior and middle are branches of the posterior cerebral arteries, and the inferior are branches of the superior cerebellar arteries. The superior supply the superior quadrigeminate bodies and the epiphysis; the middle supply both the superior and inferior quadrigeminate bodies, and the inferior the inferior quadrigeminate bodies. They all anastomose in the pia on the surface of the stratum zouale, forming a fine-meshed plexus, and from this superficial plexus the terminal branches pass into the substance of the bodies. The veins terminate in the vein of Galen (v. cerebri magna.)
The arteries of the cerebral peduncles form two groups, mesial and lateral. The mesial peduncular arteries are branches of the basilar and the posterior cerebral arteries. They pass to the medial sides of the pendunoles and supply the superior and medial part of the tegmentum. The vessels of this group which accompany the fibres of the oculomotor nerves are known as the radicular arteries; they supply the root-fibres and the nuclei of the nerves, which receive no other branches. The lateral peduncular arteries are branches of the posterior cerebral and
of Galen.
The blood-vessels of the cerebellum. — Six arteries supply the cerebellum; two, the posterior inferior cerebellar, are derived from the vertebral arteries, and the remaining four, two anterior inferior and two superior cerebellar, from the basilar artery. The course and general distribution of the arteries are described m Section V, but here it must be noted that the branches of these six vessels form a rich network in the pia mater on the surfaces of the cerebellar lobes, and that extensions of the plexus pass with the folds of the pia mater into the sulci and fissures. From the superficial plexus terminal branches pass mto the interior of the cerebellum and their collaterals form capillary plexuses in the white and grey substance. The extensions of the surface plexus are of three lengths: — (1) a longer set, which pass through the cortex of the cerebellum and supply the white substance of the corpus meduUare; (2) a set of shorter arterioles which pass through the molecular layer of the cortex and break up in its granular layer; (3) the shortest set pass into the cortex and immediately break up in its molecular layer. The meshes of the capillary plexuses in the grey susbtance are ovoidal and their axes run radially. The meshes of the plexuses in the white substance are parallel with the nerve-fibres. In addition to the vessels mentioned, a distinct branch is distributed to each dentate nucleus. This springs either from the superior cerebellar or from the anterior inferior cerebellar artery of the corresponding side.
The efferent veins of the cerebellum do not accompany the arteries; they spring from a plexus in the pia mater which receives tributaries from the interior, and they form three groups on each cerebellar surface, the vermian veins and the lateral veins. The superior vermian vein runs forward on the superior surface of the vermis and terminates in the vein of Galen. The inferior vermian vein runs posteriorly and ends in one of the transverse sinuses. The superior lateral veins open into the superior petrosal or transverse sinuses, and the inferior lateral veins into the inferior petrosal and transverse sinuses. The vein from the dentate nucleus usuaDy joins the inferior lateral veins.
The blood-vessels of the pons. — The arteries to the pons are branches of the basilar artery, and of its anterior inferior and superior cerebellar branches. The plexus in the pia mater is comparatively unimportant, and the branches which enter the substance of the pons form two main groups, the central and the peripheral. The central arteries spring directly from the basilar. They pass backward along the raphe, giving branches to the adjacent parts, and they terminate in the nuclei of the pons and those in the floor of the fourth ventricle. The peripheral arteries are radicular and intermediate. The radicular branches spring from the peripheral plexus and from the anterior inferior cerebellar arteries; they accompany the roots of the trigeminus, abducens, facial, vestibular, and cochlear nerves, supply their fibres and the adjacent parts, and they end in the grey nuclei with which the nerve-fibres are connected. The intermediate arteries enter the surfaces of the pons irregularly and break up into capillaries in its substance. The veins form a plexus on the surface. The dorsal and lateral part of this plexuis drained into the basilar vein on each side, and the inferior part is connected by efferent channels with the inferior petrosal sinus and the cerebellar veins.
The blood-vessels of the medulla oblongata. — The arteries of the medulla are derived directly from the vertebral arteries, from their anterior and posterior spinal and posterior inferior cerebellar branches, and from the basilar artery. The branches of these vessels form a plexus in the pia mater from which, and from the arteries themselves, three main groups of vessels pass into the medulla — the chorioidal, the central, and the peripheral. The chorioidal arteries are derived chiefly from the posterior inferior cerebellar arteries. They supply the chorioid plexus of the fourth ventricle. The anterior central arteries rise from the anterior spinal artery, from the basilar artery, and from the peripheral plexus; they pass caudalward along the raphe, supplying the adjacent parts of the ventral funicuh and the olivary bodies, and they break up into fine terminals in the grey substance of the floor of the fourth ventricle around the nuclei of the cranial nerves. The posterior central arteries spring from the posterior spinal arteries; they pass down the median septum of the inferior part of the medulla and supply the adjacent nervous substance. The peripheral arteries, like those of the spinal cord, are separable into radicular and intermediate groups. The radicular arteries pass from the anterior and posterior spinal branches and from the trunks of the vertebral arteries and accompany the fibres of the last six cranial nerves into the substance of the medulla. They supply the nerve-roots and adjacent white substance and they terminate in capillaries in the grey substance of the lateral part of the floor of the ventricle. The intermediate peripheral arteries spring from the arteries previously named and from the peripheral plexus, and they pass directly into the funiculi of the meduUa, where they terminate in a capillary plexus which supplies the white substance and the grey nuclei; some of these arteries, more especially those derived from the posterior inferior cerebellar and the posterior spinal arteries, extend inward to the lateral part of the floor of the fourth ventricle.
The veins which issue from the medulla form a peripheral plexus in the pia mater in which there are two main longitudinal channels, an anterior median and a posterior median vein. The former communicates posteriorly with the anterior median vein of the cord, and anteriorly with the veins of the pons and with the veins which accompany the hypoglossal nerves. The latter veins empty into the internal jugular veins. The posterior median vein is continuous caudally with the corresponding vein of the cord, and anteriorly, in the region of the calamus scriptorius, it divides into branches which join the radicular veins. The blood is carried away from the peripheral plexus mainly by the radicular veins, which pass along the roots of the last six cranial nerves. Those which accompany the hypoglossal nerves have already been referred to. The others end in the terminal parts of the transverse sinuses, the inferior petrosal sinuses, or the inferior part of the occipital sinuses.
The nerve supply of the blood-vessels of the brain consists of a perivascular plexus of sympathetic nerve-fibres upon the walls of the vessels and meduUated fibres which accompany the vessels and apparently terminate, for the most part, in the connective tissue about them. The former are thought to be vaso-motor in function; the latter probably sensory fibres of the cranio-spinal type. Nerves have been described only for the larger vessels.
IV. THE MENINGES
Three membranes, collectively called the meninges, envelope the entire central nervous system, separate it from the walls of the bony cavities in which it lies, and aid in its protection and support. They consist of feltworks in which white fibrous connective tissue predominates, and through them pass the blood-vessels which supply the central nerve-axis and the nerves by which the axis is connected with the periphery. Though there are definite spaces or cavities between them, the membranes are not wholly separated from each other, and they are both continuous with and contribute to the walls of the blood-vessels and the sheaths (epineurium) of the nerves passing through them. Beginning with the outermost, they are — (1) the dura mater, the thickest, most dense and resistant of the mem-
branes; (2) the arachnoid, the much less dense, web-hke middle membrane; and (3) the pia mater, a thin, compact membrane, closely adapted to the sm-face of the central system, into which it sends numerous connective-tissue processes. It is highly vascular in that it contains the rich superficial plexuses of bloodvessels from which the intrinsic blood supply of the central system is derived. The space between the dura mater and the arachnoid is known as the sub-dural
The Duea Mater
In the fresh condition the dura mater appears as a bluish-white, exceedingly resistant membrane, forming the outermost envelope of the entire central nervous system. Its external surface or that next to the bony wall is rough, while its internal surface appears smooth, due to the fact that the subdural cavity partakes of the nature and has the hning of a lymph-space. The cranial dura mater consists of two distinct, closely associated layers, the outermost of which serves as the internal periosteum of the cranial bones. The spinal dura mater is described as consisting of but one layer. The internal periosteum of the spinal
SPINAL DURA MATER
canal, though continuous at the foramen magnum with the outer layer of the cranial dura mater, is not considered a part of the spinal dura mater, from the fact that it is so widely separated from the layer actually investing the spinal cord. Thus, since the cranial and spinal portions of the dura mater differ, they are described separately.
The spinal dura mater is a fibrous tube with funnel-shaped caudal end which encloses and forms the outermost support of the spinal cord. It consists of but one layer and this corresponds to the inner layer of the cranial dura mater. It begins at the foramen magnum and terminates in the spinal canal at about the level of the second piece of the os sacrum. It is firmly attached to the periosteum of the surrounding bones only in certain localities: —
(1) The upper end of the tube blends intimately with the periosteum of the margin of the foramen magnum, and thus in this locality it becomes continuous with the outer layer of the cranial dura mater. Also in this locahty it is attached firmly, though less intimately, to the periosteum of the posterior surfaces of the second and third cervical vertebrae. This locahty may be considered the upper fixation-point of the spinal dura mater. (2) It extends laterally and contributes to the connective tissue investments of each pair of spinal nerves, and as such it passes into the intervertebral foramina and becomes continuous with the periosteum lining each. (3) Along its ventral aspect the spinal dura mater is attached by numerous proc-
esses to the posterior longitudinal ligament of the vertebral canal. These attachments are more or less delicate, loose, and irregular, and are easily torn or cut in removing the specimen. They are stronger and more numerous in the cervical and lumbar regions than in the thoracic. (4) In the space between the dura and the walls of the vertebral canal (epidural cavity) lies the rich internal vertebral venous plexus, and along the lateral aspect the dura is occasionally connected with the periosteum through the tissue of the walls of the vessels of this plexus, especially in case of the vessels which penetrate the dura. Along its dorsal aspect the spinal dura mater is practically free from the wall of the vertebral canal. (5) At its lower and funnel-shaped extremity, opposite the second sacral vertebra, the tube suddenly contracts into a filament extending into the coccyx and breaking up into a number of processes which become continuous with the periosteum of the dorsal surface of the coccyx. This filament is the coccygeal ligament or filum of the dura mater, and its attachment may be considered the lower fixation-point of the spinal dura mater. (See figs. 613 and 715). The extent of the tube is maintained chiefly by means of the two fixation-points, for all the other_ attachments are sufficiently loose to permit of the movements of the vertebral column.
The inner surface of the spinal dura mater appears smooth, but upon closer examination it is found to be connected with the arachnoid by a few delicate subdural trabeculse — occasional fine strands of connective tissue bridging the subdural space (fig. 725). Along its lateral aspects the inner sm-face is at intervals quite firmly attached to the pia mater by the dentations of the ligamenta denticulata, which are prolonged through the arachnoid.
Further, it is continuous at intervals with both the pia mater and arachnoid by way of the connective-tissue sheaths of the nerve-roots which are prolonged from the pia and blend with the dura mater in the passage of the nerve-roots through it. The dura is also pierced by the spinal rami of the vertebral arteries, and the connective tissue of the outer walls of these vessels blends with aU three of the meninges. The filum terminate of the pia mater extends below the termination of the spinal cord into the point of the funnel-shaped end of the dura mater, and there blends with it in line with the coccygeal ligament of the outer surface.
The tube of the spinal dura mater varies in calibre with the variations in the diameter of the spinal cord. However, the termination of its cavity occurs about seven segments below the termination of the spinal cord. This extension contains the long intra-dural nerve-roots forming the cauda equina, and the calibre of this part, before its sudden contraction, is about as great as that found in any
Fig. 718. — The Dura Mater Encephali of the Base op the CRANitrM. (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.) As each pair of nerve-roots of the cauda equina passes outward, they lie free for a variable distance in a tubular extension of the dura before the latter blends with and contributes to the thickness of their sheath.
The subdural cavity, the space between the dura mater and the arachnoid, is the thinnest of the meningeal spaces. Along the ventral aspect especially, the spinal arachnoid is quite closely applied to the inner surface of the dura mater. It contains a small amount of cerebro-spinal fluid (lymph) which prevents friction between the opposing surfaces, and is continuous with the fluid in the like space of the cranial meninges.
The space communicates with the venous sinuses of the cranium in the region of the Pacchionian bodies, and its fluid is likewise in contact with the blood-vessels passing through it. It is probably continuous with the lymph-spaces of the nerve-roots passing through it, for colored fluids injected into it pass into the nerve-roots. The arachnoid is so thin and gauzeUke that a ready interchange of fiuids between this space and the subarachnoid space is possible by simple filtration.
The cranial dura mater [dura mater encephali]. — The dura mater investing the brain performs a double function — it serves as an internal periosteum for the cranial bones and gives support and protection to the brain. In conformity with its double function it consists of two layers, easily separable in the child, but closely adhering to each other in the adult, except in occasional localities, where there exist small clefts lined with endothelium. The large blood sinuses and venous lacunse, corresponding to the internal vertebral venous plexus of the vertebral canal, are placed between the two layers and the semilunar ganglia of the trigemini also lie between them. The cranial dura begins with the adhesion of the spinal dura mater to the periosteum at the foramen magnum, and it forms a saclike envelope about the entire encephalon. Consisting of two layers, it is a much thicker membrane than that of the spinal cord.
Dentate nucleus Tentorium cerebelli
This is due to the many fine bundles of connective tissue and the blood-vessels which pass between the dura and the cranial bones and which are partially pulled out of their openings in the latter in the process of separation. The abundance of these connections, and, therefore, the degree of adhesion to the bones, varies in different localities. The separation is much less difficult from the inner table of the bones of the vault of the cranium than from the bones of the base of the cavity. The adhesions to the vault of the cranium are most firm along the lines of the sutures. This is due to the fact that during the period before the sutures are closed the outer layer of the dura mater is directly continuous with the external periosteum, and, in consequence of this condition during development, the connective-tissue connection is more abundant along these lines and some is even caught in the closure of the sutures. Along the vault there are occasionally noticed small lymph-spaces between the bone and the dura mater. The stronger adherence to the base of the cranial cavity is due to the numerous foramina in the floor, through which all the larger cranial blood-vessels and the cranial nerves pass, and the dura mater is continuous with the connective-tissue investments of these as well as with the periosteum lining the foramina. Also the floor of the cavitj' is more uneven than the vault, and the projections of the bones here tend to increase the firmness of attachment. The weight of the brain upon the floor probably contributes to the result.
The inner surface of the inner layer of the cranial dura mater forms the outer boundary of the subdural cavity. Except for the occasional delicate subdural trabeculse and the passage of blood-vessels and nerve-roots, this surface appears
The subdural cavity of the base of the brain is prolonged a short distance outward along the roots of the various cranial nerves before it is obUterated by the blending of the dura mater with the sheaths of the nerves. This outward extension of the space is most marked about tlie optic and auditory nerves. In the optic especially, the dura mater remains separate from the nerve throughout its length, only fusing with its sheath upon the posterior surface of the ocular bulb (fig. 718).
One of the most striking differences between the cranial dura mater and that of the spinal cord is that the inner layer of the former undergoes striking septa-like duplications or folds, forming exceedingly strong partitions which project between the larger subdivisions of the encephalon. These are four in number, two large and two small — the falx cerebri and the tentorium cerebelli; the falx cerebelli and the diaphragma sellse. The larger enclose within their folds the great venous sinuses, into which most of the spent blood of the encephalon collects to pass outward by way of the internal jugular veins (figs. 720, 721).
fold which projects vertically from the vault into the longitudinal fissure between the cerebral hemispheres. It begins attached to the crista galli in front, and arches to terminate by blending with the superior surface of the hirozontally placed tentorium cerebelli. Its convex, superior border joins the outer layer of the dura along the medial plane of the vault, and encloses the superior sagittal sinus. Its concave border is free and contains in its posterior two-thirds the smaller inferior sagittal sinus. The anterior and narrower end is often perforated and occasionally so much so as to appear as a coarse, fibrous reticulum. The posterior part of the concave border touches the upper surface of the corpus callosum, but the anterior part, which does not descend so low, is separated from the corpus callosum by a part of the subarachnoid space. The base of the fold which slopes downward and blends with the upper surface of the tentorium cerebelli, contains the straight sinus running along the line of junction.
tent-shaped covering. Its superior surface is in relation with the tentorial surfaces of the hemispheres, and its inferior surface conforms accurately to the superior surface of the cerebellum. The outer or convex border of the fold is attached on each side to the posterior clinoid process, the superior border of the petrous portion of the temporal bone, the mastoid portion of the temporal bone, the posterior inferior angle of the parietal bone, and the horizontal ridge of the occipital bone. The transverse sinus lies in this border. From the internal occipital protuberance to the mastoid portion of the temporal bone and along the petrous part of the temporal bone it encloses the superior petrosal sinus.
The greater part of the inner or anterior border of the tentorium is free, and it forms the superior and lateral boundaries of an arched cavity, the tentorial notch or foramen ovale of Pacchioni, which encloses the mesencephalon, and through which ascend the cerebral peduncles and the posterior cerebral arteries. The anterior extremities of the inner border cross the outer border, and they are attached to the anterior clinoid processes. A depressed angle is formed between
Superior sagittal sinus
the inner and outer borders of the tentorium in the middle fossa of the skull at the lateral portion of the posterior clinoid process, and in this angle the root of the oculo-motor nerve pierces the inner layer of the dura mater.
The falx cerebelli is a small, sickle-shaped, triangular fold which projects forward into the small groove {-posterior cerebellar notch), between the hemispheres of the cerebellum. Its base is attached to the tentorium; its postero-inferior border, along which runs the occipital sinus, is attached to the internal occipital crest. Its anterior border is free, and its apex, which lies immediately above the foramen magnum, usually bifurcates as it disappears anteriorly, grasping the foramen magnum from behind. Bifurcation is always the case when the internal occipital crest splits below to enclose a vermiform fossa.
The diaphragma sellae is a small circular fold, deficient in the centre, which projects horizontally from the margins of the hypophyseal fossa or sella turcica. Its lateral border is attached to the clinoid processes and the limbus of the sphe-
noid, and its medial border forms the boundary of the foramen of the diaphragma sellce and surrounds the infundibulum. Its superior surface is in relation with the base of the brain, and its inferior surface is in relation with the hypophysis, which it binds down in the hypophyseal fossa.
lacunae.
Meckel's caves are two cleft-like spaces or niches which lie, one on each side, in the trigeminal impression on the apex of the petrous portion of the temporal bone. Each space lodges the semilunar (Gasserian) ganglion and the trigeminus and masticator nerves of the corresponding side, and it communicates with the subdm-al space in the posterior fossa of the cranium by an oval opening, which lies above the superior border of the petrous portion of the temporal bone and inferior to the superior petrosal sinus.
vestibuli.
The venous sinuses and lacunae. — The cranial blood sinuses have already been fully described in the account of the vascular system, and it is sufficient to note here that they are continuous, on the one hand, with the meningeal veins, and, on'the other, with the veins outside the cranial waDs. The vessels which establish communication between the blood sinuses and the extracranial veins are referred to collectively as emissary veins. They possibly help to maintain the regularity of the cranial circulation, and they have therefore a certain amount of practical importance.
The sinuses which are connected with the extracranial^veins by emissary veins are the superior sagittal, the transverse (lateral), and the cavernous. Three or four emissary veins pass from the superior sagittal sinus; — one passes through the foramen caecum and communicates with the veins of the roof of the nose, or, through the nasal bones, with the angular veins. Two pass through the parietal foramina and establish communications with the occipital veins, and a fourth, which is very inconstant, pierces the occipital protuberance and joins the tributaries of the occipital veins. Connecting each lateral sinus with the extracranial veins
THE ARACHNOID 917
there are, as a rule, two emissary veins: — one, the mastoid emissary vein, which passes through the mastoid foramen to the occipital or posterior auricular vein; and the other, the post-condyloid vein, which traverses the condyloid (posterior condyloid) foramen and joins the suboccipital plexus. The cavernous sinus is in communication anteriorly with the superior ophthalmic vein, and through the latter with the angular vein; it is connected with the pterygoid plexus by emissary veins which pass either through the foramen ovale or the foramen Vesalii, and with the pharyngeal plexus by small venous channels which accompany the internal carotid artery through the carotid canal.
The venous lacunae or spaces are small clefts lined by endotheUum which communicate with the meningeal veins and with the blood sinuses. They also have communications with the emissary veins and the diploic veins. They lie between the outer and inner layers of the dura mater, the majority of them at the sides of the superior sagittal sinus, but others are found in the tentorium associated with the transverse sinuses and the straight sinus.
Blood-vessels. — The blood supply of the cranial dura mater is derived from the meningeal arteries, which ramify in its outer layer. The more important of these arteries have already been described in the account of the vascular system, and it is only necessary here to recall the fact that the greater part of the dura mater above the tentorium cerebelli is supplied by branches of the middle meningeal arteries. These are reinforced — (1) at the vertex by branches of the occipital arteries which enter through the parietal foramina; (2) in the middle fossa by the small meningeal arteries' and by meningeal branches of the internal carotid, lacrimal, and ascending pharyngeal arteries; and (3) in the anterior fossa by meningeal branches of the anterior and posterior ethmoidal arteries.
The dura mater in the posterior fossa of the skull, below the tentorium cerebelU, also receives branches from the middle meningeal arteries, but its blood supply is derived mainly — (1) from the meningeal branches of the vertebral arteries which enter- the fossa through the foramen magnum, (2) from meningeal branches of the occipital arteries which enter through the mastoid and hypoglossal foramina, and (3) from meningeal branches of the occipital and ascending pharyngeal arteries which enter through the jugular and hypoglossal (anterior condyloid) foramina.
The meningeal veins accompany the arteries as vena comitantes, usually one vein with each artery. The middle meningeal artery usually has two venae comitantes. The meningeal veins communicate with the venous sinuses and with the diploic veins, and, unlike ordinary veins, they do not increase much in calibre as they approach their terminations.
The nerves of the dura mater are partly derived from the sympathetic filaments which accompany the arteries and partly from the cranial nerves. The nerves, other than sympathetic filaments, which supply the cranial dura mater are sensory fibres derived from the trigeminus and vagus nerves, and possibly from the first cervical nerves. The branches from the trigeminus are derived from the three divisions of that nerve on each side, and it has been stated that branches are given from the nasal branch of the ophthalmic division to the dura mater in the anterior fossa.
The meningeal branch of the ophthalmic division of the trigeminus supplies the tentorium ; that from the maxillary division accompanies the branches of the middle meningeal artery. The meningeal branch of the mandibular division (nervus spinosus) passes into the skull through the foramen spinosum and is distributed to the dura mater over the great wing of the sphenoid and to the mastoid ceOs. The "recurrent branch of the hypoglossal nerve" passes to the dura mater of the posterior fossa of the cranium. This recurrent or meningeal branch of the hypoglossal nerve really consists of fibres derived from the superior cervical ganglion of the sympathetic, and contains sensorj' fibres from the first and second cervical nerves. The meningeal branch of the vagus springs from the ganglion of the root of that nerve, and is distributed in the posterior cranial fossa. The sympathetic filaments are distributed to the smooth muscle of the walls of the blood-vessels.
The cranial subdiiral cavity is not of uniform thickness throughout, being thinner along the basal aspect of the encephalon. The lymph contained in it is usually but little more than is sufficient to keep moist its bounding surfaces. It is continuous with the lymph capillaries of the nerves and those of all the tissues it bathes, and it is continuous with the similar cavity of the spinal canal. Its lymph is in free contact with the blood-vessels passing through it and with those in the tissues it bathes, and it is replenished by filtration through their walls. Though extensive, the subdural space is thin at best, for the dura mater is quite closely applied to the second of the three meninges.
The arachnoid or ' serous ' membrane is the middle of the three meninges of the central nervous system. As in the case of the other two, an attempt is made to give this membrane a name descriptive of its texture. It is a gauzy reticulum of almost web-like delicacy, which in reality pervades the space it occupies.
Its outer surface, or that closely related to the dura mater and bounding the subdural cavity alone shows a sufficiently organized structure to merit the name of membrane. This surface is covered by a layer of endothehum which is identical with that lining the inner surface of the dura mater and is continuous with it by way of the endothehal cells covering the blood-vessels,
the nerve-roots, the ligamenta dentioulata of the spinal cord, and the occasional delicate trabeculae passing between the dura mater and the arachnoid. Immediately under the endothehum, the connective-tissue fibres of the arachnoid are woven into a very thin, more or less compact web. This, however, quickly grades into a loose, spongy reticulum which pervades the thick subarachnoid cavity throughout, and the strands of which are directly continuous into the more compact tissue of the pia mater. Thus an inner surface can hardly be claimed. This loose, sponge-like arachnoid tissue holds the cerebro-spinal fluid of the subarachnoid cavity, the meshes of the sponge constituting a reticular web of intercommunicating spaces hned by endothehoidal cells covering the strands of the web. The cranial subarachnoid cavity is larger, and the strands of the web are relatively more abundant than in that of the spinal canal. In addition, the cavity is traversed by the spinal and cranial nerves, by the blood-vessels passing to] and from the pia, and, in the spinal canal distinctively, it is traversed by the ligamenta denticulata and the filum terminale. Through these the arachnoid is further continuous with the pia mater.
The cranial arachnoid is directly continuous into that of the spinal cord, and in the two localities does not differ as much as does the dura mater. Within the cranium, the arachnoid does not closely follow the surface of the encephalon. It is folded in between the cerebellum and cerebral hemispheres, following the contour of the tentorium cerebelli, but it does not dip into the fissures and sulci except the anterior part of the longitudinal fissure and slightly into the lateral (Sylvian) fissure. Otherwise it fills in the inequalities of surface of the encephalon, its outer surface forming a sheet enveloping the whole and bridging over the sulci and the deeper grooves between the gross divisions. Upon the summits of the gyri it is more closely applied to the pia mater, and there its reticulum becomes so dense
Fig. 723. — Diagram showing the Relations op the Pia Mater, the Arachnoid, and the Stibarachnoid Cavity to the Brain. Pia mater Subarachnoid cavity
The arachnoid folds in between the cerebellum and medulla oblongata, and at the base of the brain it ensheathes the olfactory bulbs and tracts, and its outer surface forms a continuous sheet stretching from one temporal lobe to the other and bridging over the interpeduncular fossa and the inequahties of surface in the region of the optic chiasma and the stems of the lateral fissures. Obviously, therefore, the subarachnoid cavity between its outer surface and the pia mater is of considerable depth in certain localities. These localities comprise the subarachnoid cisternoe. These occur where the cavity at the base of the brain is especially large, and make possible a 'water-bed' which serves to protect the brain from injurious contact with the bones.
posteriorly with the subarachnoid cavity about the medulla.
(3) The cisterna superior Ues in the angle between the splenium of the corpus callosum and the superior surfaces of the cerebellum and the mesencephalon, and is connected ventrally, around the cerebral peduncles, with the cisterna basalis.
(4) The cisterna cerebello-medullaris (cisterna magna) is the cavity between the inferior surface of the cerebellum and the dorsal surface of the medulla oblongata. It is continuous below into the spinal subarachnoid space. The fluid in this cavity is directly continuous with that in the fourth ventricle by way of the foramen of Magendie (median aperture of the fourth ventricle).
Pacchionian bodies [granulationes arachnoideales] (fig. 724.) — In certain situations, more particularly along the margins of the longitudinal fissure, particularly in the frontal region, and to a much less extent upon the superior surface of the vermis of the cerebellum, the subarachnoid tissue elaborates numerous small, ovoid or spherical nodules, the Pacchionian bodies. Each body or arachnoid villus consists of a retiform network of subarachnoid substance and its meshes are filled with cerebro-spinal fluid. The Pacchionian bodies on the vertex of the brain project through the inner layer of the dura mater, both into the superior sagittal sinus and into the venous spaces or parasinoidal sinuses which lie at the sides of that sinus, and, as they become larger, they press against the outer layer of the dura mater and produce ovoid depressions in the inner plate of the cranium.
Fig. 724. — Coronal Section transverse to the Great Longitudinal Fissure, Showing THE Meninges. (Key and Retzius.) Subarachnoid space Superior sagittal sinus Pacchionian body
They probably facihtate the passage of lymph from the subarachnoid cavity into the blood sinuses, and thus may aid in relieving pressure within. On the other hand, through them the cerebro-spinal fluid is replenished at need from the blood plasma. They are not present at birth, but they appear at the tenth year and increase in number and size with advancing age. They are less marked in the female than in the male.
The spinal arachnoid (figs. 725, 726) is a loose, reticular sac which is most capacious about the lumbar enlargement of the spinal cord and about the Cauda equina. Like that of the encephalon, the portion next to the dura mater alone resembles a membrane, being a loosely organized feltwork, covered on the side of the subdural cavity by a layer of endothelium common to that cavity. Throughout its length the spinal subarachnoid cavity is relatively wide, and, as in the cranium, contains a fine, spongy, web-like reticulum, numerous threads of which are continuous with the pia mater. This spongy tissue is the inner modification of the arachnoid, and its meshes are occupied by the cerebro-spinal fluid. It is not so abundant as in the cranial subarachnoid cavity.
In addition to the delicate threads, the arachnoid is more firmly attached to the pia mater by three incomplete partitions. The most continuous of these is arranged along the dorsal mid-line and is known as the septum posticum of Schwalbe (subarachnoid septum). This may be described as a linear accumulation of the spongy tissue which pervades the subarachnoid space. It is most incomplete in the upper cervical region, where it becomes merely a line of threads connecting with the pia. It is most complete as a septum in the lower cervical and in the thoracic region, but at best it maintains a spongy character. The other two partitions are
formed by the denticulate ligaments, which extend laterally from either side of the spinal cord, connecting the pia and dura mater and involving the arachnoid in passing through it. Within the subarachnoid cavity these form more or less complete septa, though outside the arachnoid they are attached to the dura only at the intervals of their pointed dentations. They belong to the pia mater and will be described with it. The arachnoid is further continuous with the pia by way of the connective-tissue sheaths of the roots of the spinal nerves and the bloodvessels passing through the subarachnoid cavity.
The cerebro-spinal fluid. — The subarachnoid cavity is the great lymph-space of the central nervous system. That of the spinal region is directly continuous into that of the cranium, and the fluid contained communicates freely with that in the ventricles of the brain and the central canal of the meduUa and spinal cord by way of the foramen of Magendie or medial aperture into the fourth ventricle. In addition, there are the lateral apertures into the fourth ventricle and there is possible an interchange of fluid between the lateral ventricle and the subarachnoid cavity of the base of the brain by diffusion through the thin floor of the chorioid fissure. The arachnoid throughout is not a membrane sufficiently compact to seriously oppose diffusion between the fluid contained in its cavity and that contained in the subdural cavity, and the endotheUum covering it probably even facilitates such activities. The cerebro-spinal fluid occupying the cavities is a transparent fluid of a slight yellow tinge, characteristic of the
Epidural trabecule to periosteum
lymph in other lymph-spaces of the body. It is not very great in amount, probably never exceeding 200 c.c. in normal conditions. It is greatest in amount in old age, when the cavities are larger, due to atrophy and shrinkage of the nervous tissues. It collects from the lymph spaces in the meninges, and from exudation through the walls of the vascular chorioid plexuses and sinuses of the system it bathes. Its amount may be temporarily increased by a period of increased blood-pressure in the cranial vessels. Pressure due to its abundance may be relieved by diffusion through the membranes containing it, and especially through the viUi of the Pacchionian bodies into the venous sinuses and lacunae and thence into the venous system through the internal jugular veins.
The pia mater, the third of the meninges, is a thin membrane which envelopes and closely adheres to the entire central nervous system and sends numerous processes into its substance. It likewise contributes the most proximal and compact portion of the sheaths worn by the nerve-roots in their passage through the meningeal spaces. It is very vascular in that the superficial plexuses of blood-vessels of
both the brain and spinal cord ramify in it as they give off the central branches into the nervous substance. The structure and arrangement of the membrane vary somewhat in the cranial and spinal regions.
The spinal pia mater consists of two layers, an inner and an outer. It is thicker and more compact than that of the encephalon, due to the extra development of its outer layer, which is in the form of a strong, fibrous layer with the fibres arranged for the most part longitudinally.
The spinal pia mater also appears less vascular than the cranial from the fact that the blood-vessels composing the plexus lying in it are obviously much smaller than those of the encephalon. Its inner layer is a thin feltworlt of fibres which is closely adherent to the surface of the spinal cord throughout, sending numerous connective-tissue processes into it which contributes to the support of the nervous tissues. The larger of these processes carry with them the numerous intrinsic blood-vessels from the superficial plexus. The two layers are closely connected with each other, and are distinguished by the difference in the arrangement of their fibres.
The membrane dips into the anterior median fissure and bridges it over by forming an extra thickening along it. This thickening appears as a band along the mid-line of the ventral surface of the cord, the linea splendens (fig. 717). It carries, or ensheathes, the anterior spinal artery, the largest of the arterial trunks of the superficial ple.xus (fig. 725).
The pia mater contributes the innermost and most compact portion of the epineurium of each of the nerve-roots, and thus, upon the roots, it is prolonged laterally into the intervertebral foramina, where the dura mater blends with it in producing the increased thickness of the epineurium.
From each side of the cord the pia mater gives off a leaf-like fold, the denticulate ligament, which spreads laterally toward the dura mater midway between the lines of attachment of the dorsal and ventral nerve-roots. The outer border of this fold is dentate or scalloped into about twenty-one pointed processes, which extend through the arachnoid and are attached to the inner surface of the dura mater. The dentations are usually inserted between the levels of exit of the roots of the spinal nerves, the uppermost one a little cephalad to the first cervical nerve and the region where the vertebral artery perforates the dura mater; the most caudal one between the last thoracic and first lumbar nerves, or, between the last two thoracic nerves. The ligaments, aided slightly by the septum posticum, serve to hold the spinal cord more or less suspended in the subarachnoid cavity.
Below, at the sudden, conical termination of the spinal cord in the lumbar portion of the spinal canal, the pia mater is spun out into a thin, tubular filament, the filum terminale, which continues caudalward into the sac formed by the dura mater about the cauda equina, and at the end fuses with the dura mater in line with the filum of the spinal dura mater (coccygeal ligament) of the outside (figs. 613, 715).
The cranial pia mater is closely applied to the external surface of the brain, dipping into all the fissures, furrows, and sulci. It is connected with the arachnoid by numerous filaments of the spongy subarachnoid tissue and by the bloodvessels traversing the subarachnoid cavity. It is also pierced by the cranial nerves, and furnishes them their sheaths, which become continuous with the arachnoid and dura mater.
Its outer surface bounds the subarachnoid cavity. It is with difficulty separable into two layers of mixed white fibrous and elastic connective tissue, with slightly pigmented connective-tissue cells enmeshed between them. Its inner surface sends a large number of fibrous processes into the nervous substance, which blend with the neuroglia and aid in the support of the nervous elements. The larger of these processes accompany the central arterial and venous branches of the rich superficial plexuses of blood-vessels contained in the pia on the surface of the brain. Pieces of the pia when pulled off and placed in water present a flocculent appearance as to their inner surfaces, due to these processes having been pulled out.
The cranial pia mater sends strong, vascular duplications into two of the great fissures of the encephalon; viz., the transverse cerebellar fissure, between the cerebellum and the medulla oblongata, and the transverse cerebral fissure, between the cerebellum, mesencephalon, and thalamencephalon, and the overhanging cerebral hemispheres. These duplications are spread over the cavities of the fourth and third ventricles, and are known as the chorioid telce of these ventricles respectively.
Chorioid plexus
The tela chorioidea of the fourth ventricle lies in the transverse cerebellar fissure, between the inferior surface of the cerebellum (vermis chiefly) and the dorsal surface of the medulla (fourth ventricle). The two layers of this fold of the pia remain separate and a portion of the cisterna posterior of the subarachnoid cavity lies between them. The inferior of the layers is the tela chorioidea (fig. 727.) It is triangular in shape, with its base cephalad at the nodule of the vermis and its apex below at the level of the tuber vermis. The superior layer of the fold is the pia mater of the vermis. The tela chorioidea is strengthened by the epithelial roof (ependyma) of the fourth ventricle and is continuous with the pia mater of the medulla oblongata and spinal cord. In roofing over the fourth ventricle the tela chorioidea of the fourth ventricle constitutes the ligula and the obex. A little above the calamus scriptorius it is pierced by the foramen of Magendie and the two lateral apertures into the fourth ventricle.
In front of the foramen of Magendie the vessels of the chorioid tela, which are derived from the posterior inferior cerebellar arteries, form two longitudinal, lobulated strands which invaginate the epithelial roof of the ventricle, one on either side of the mid-hne, and project into its cavity. These form the chorioid
THE CHORIOID TELA
plexus of the fourth ventricle. At the base of the tela the two chorioid plexuses join each other and then turn transversely lateral ward into the lateral recesses of the ventricle, where they pass behind the restiform bodies and form the ' cornucopicB.'
The chorioid tela of the third ventricle, or velum interpositum, is a triangular duplication of the pia mater which extends between the fornix above and the thaiami and third ventricle below, and in front fuses with the brain substance at the interventricular foramina.
In the transverse cerebral fissure the layers of pia forming this tela are separate, the upper being the pia of the under surface of the corpus caUosum and continuous with that of the tentorial surfaces of the occipital lobes; the lower being continuous into the pia enfolding the epiphysis, and covering the mesencephalon, anterior medullary velum, and cerebellum. The
eminence
layers forming the portion of the dupUcation which roofs over the third ventricle are loosely adherent to each other and form the tela chorioidea proper of that ventricle. The upper surface of this portion is in relation with the fornix and its lower surface, covered by the epithelial chorioid lamina, lies laterally over the superior surfaces of both thalami, and mesiaUy forms the roof of the third ventricle between them. The epitheUum or ependyma is continuous with that covering the thalami and lining the ventricles. Between the two layers of this portion, and embedded in a small amount of the spongy subarachnoid tissue retained between them, are the two veins of Galen, the internal cerebral veins. Posteriorly these veins unite in the region of the epiphysis to form the single great cerebral vein (vena cerebri magna) which empties into the straight sinus. Anteriorly the veins of Galen receive the veins of the septum pellucidum from each lamina of the septum pellucidum above, and also the terminal vein (vein of corpus striatum), lying in the stria terminahs of the thalamus, empties into them from each side.
low into each lateral ventricle. The blood-vessels of the border proj ecting into the lateral ventricle are amplified into a plexus which appears as a strip of reddish, lobulated, villus-like processes known as the chorioid plexus of the lateral ventricle. The plexus, being in the border of the tela, begins at the interventricular foramen, extends through the body or central portion of the ventricle, and downward into its inferior cornu. It is most developed at the junction of the body with the inferior cornu, and is there known as the glomus chorioideum.
From the under surface of the chorioid tela of the third ventricle, hanging down on either side of the mid-line into the cavity of the ventricle, are two other longitudinal, lobulated strands of blood-vessels which are the chorioid plexuses of the third ventricle. At the anterior end of the third ventricle these two plexuses join with each other and also with the plexus of the lateral ventricle of each side through the interventricular foramina.
The chorioid plexuses of both the ventricles are covered by a layer of ependyma, epithelial chorioid lamina, which is but a reflexion of the ependyma lining the cavities throughout and represents the remains of the germinal layer of the embryonic brain vesicles. The blood-vessels
Fifth ventricle Fornix
of the chorioid plexus of the lateral ventricle receive blood by the chorioid artery (a direct branch of the internal carotid), which enters the plex-us through the chorioid fissure immediately mesial to the uncus, and also by the chorioidal branches of the posterior cerebral artery, which supply the plexus of the body of the ventricle. The chorioid plexuses of the third ventricle receive blood chiefly by branches from the superior cerebellar arteries. The greater part of the blood of both plexuses passes out by way of the tortuous chorioid veins, which, at the interventricular foramen, empty into the vense terminates (veins of the corpus striatum), which, in their turn, go to form the greater part of the veins of Galen. Thence the blood passes by way of the vena cerebri magna into the straight sinus. It is probable that a large part of the oerebro-spinal fluid of the third and lateral ventricles is derived by diffusion through the walls of the vessels of the chorioid plexuses.
peripheral nervous system. This system, abundantly attached to the central system, consists of numerous bundles of nerve-fibres which divide and ramify throughout the body, anastomosing with each other and forming various plexuses, large and small. The terminal rami divide and subdivide until the divisions attain the individual nerve-fibres of which they are composed, and finally the nervefibres themselves divide and terminate in relations with their allotted peripheral elements. It is by means of this system that stimuli arising in the peripheral tissues are conveyed to the central system, and that impulses in response are borne from the central system to the peripheral organs. For pm-poses of description, as well as upon the basis of certain differences in structm-e, arrangement, and distribution, the peripheral nervous system is separated into two main divisions: — (1) the cranio-spinal and (2) the sympathetic system.
Both of these divisions include numerous ganglia or peripheral groups of nervecells from which arise a considerable proportion of the fibres forming their nervetrunks, but neither of the divisions may be considered wholly apart from the central system nor are they independent or separate from each other. The sensory or afferent fibres of the cranio-spinal nerves pass by way of the afferent nerveroots into the central system and contribute appreciably to its bulk, and the motor or efferent fibres of these nerves have their cells of origin (nuclei) situated within the confines of the central system. The sympathetic system is intimately associated with the cranio-spinal, and consequently with the central system — (1) by means of fibres which enter and terminate in the cranio-spinal gangha and transfer impulses which enter the central system; (2) by efferent fibres of central origin which com'se in the nerve-trunks and terminate in the ganglia of the sympathetic system; (3) also, the sympathetic trunks usually contain numerous afferent cranio-spinal fibres which thus course to their peripheral termination, usually in the so-called 'splanchnic area,' or domain of the sympathetic, in company with the sympathetic fibres. Likewise the peripheral branches of the cranio-spinal nerves often carry for varying distances numerous sympathetic fibres which are on their way to terminate either in other sympathetic ganglia or upon their allotted peripheral tissue-elements.
The following differences between the cranio-spinal and sympathetic systems of nerves may be cited: — (1) The cranio-spinal nerves are anatomically continuous with the brain and spinalcord; probably no fibres arising in the sympathetic gangha actually enter the central system other than for the innervation of its blood-vessels, (2) The gangha of the cranio-spinal nerves all lie quite near the central axis, in hne on either side of it, and at more or less regular intervals; the sympathetic gangha are scattered throughout the body tissues, are far more numerous and more variable in size, and probably only the larger of them are symmetrical for the two sides of the body. (3) The cranio-spinal nerves are paired throughout, and the nerves of each pair are symmetrical as to their origin and also, with certain exceptions (notably the vagus), in their course and distribution; most of the larger and more proximal of the sympathetic nerve-trunks are symmetrical for the two sides of the body; many of them are not, and many of the smaller and most of the more peripheral nerves and gangha, large and srnall, are not paired at all. (4) Even in their finer twigs, the cranio-spinal nerves of the two sides probably do not anastomose with each other across the mid-hne of the body; the sympathetic nerves do so abundantly, especially within the body cavity. (5) The cranio-spinal nerve; are distributed to the ordinary sensory surfaces of the body and the organs of special sense and to the somatic, striated or 'voluntary' muscles of the body; the sympathetic fibres are devoted chiefly to the supply of the so-caUed involuntary muscles of the body, including the smooth muscle in the walls of the viscera and in the walls of the blood and lymph vascular-systems, while others serve as secretory fibres to the glands. (6) Cranio-spinal nerve-fibres are characterized in general by well-developed medullary sheaths, making the nerves appear as white strands; most of the sympathetic fibres are non-medullated, some are completely and some partially medullated, but none possess as thick medullary sheaths as those of the cranio-spinal nerves. Thus sympathetic nerves appear as grey strands.
The cranio-spinal nerves.^ — There are forty-six pairs of cranio-spinal nerves, of which thirty-one pairs are attached to the spinal cord (spinal nerves) and fifteen pairs to the encephalon (cranial nerves) . The spinal nerves are the more primitive and retain the typical character, i. e., each is attached to the spinal cord by two roots, a dorsal or sensory ganglionated root, and a ventral, which is motor, and thus not ganglionated. Most of the cranial nerves have only one root, which in come cases corresponds to a dorsal root and therefore has a ganglion, and in other cases corresponds, physiologically at least, to a ventral root of a spinal nerve. Among other differences, the fibres of the first cranial nerve, for example, do not collect to form a distinct nerve-trunk.
Customarily, the cranial nerves are described as comprising twelve pairs and each is referred to by number. However, present knowledge of their origin, central connections and peripheral distribution suggests that those enumerated as the fifth, seventh, and eighth pairs under the old nomenclature are better each separated into its two component nerves, each of which merits a separate description and a separate name. None of the cranial nerves corresponds closely to a typical spinal nerve with its motor and sensory root. The so-called motor portion of the fifth is no more its motor root than is the seventh nerve. The sensory portion of the seventh is not wholly sensory and rather resembles the ninth pair in distribution, and it has long been commonly referred to as a separate nerve. The two parts of the eighth nerve, both sensory, are known to be wholly different in functional character and are so named. Further, the names of the nerves, descriptive of their function, are pedagogically much more eflacient than the use of numbers in referring to them.
Separating the three pairs mentioned, each into its two nerves, gives fifteen pairs instead of twelve. Their names and functional nature are given in the following table. The Roman numerals given in parentheses correspond to the serial numbers given when twelve pairs only are considered. It is also customary to enumerate the cranial nerves from in front backward and caudalward, and this custom is followed here, but again it would be pedagogically better to take them in the reverse order. Then each in its turn could be directly considered as in continuous series with the spinal nerves below and the similarities to and progressive modifications from the spinal type could be better realized. It will be remembered that somatic motor or efferent fibres are those which terminate directly upon the fibres of skeletal muscle while visceral motor fibres transfer their impulses to sympathetic neurones, and the axones of the latter terminate upon gland cells and upon the fibres of cardiac and smooth muscle.
Motor| yjgj.gj.^j Glands and vessels. Sensory Alimentary canal, lung, heart. Motor I Somatic Larynx, pharynx. \ Visceral Alimentary canal, heart, larjmx, trachea, lung.
The cranial nerves, like the spinal nerves, are developed from cells of the primitive neural tube and, beginning with the fifth pair downward, all the sensory nerves are developed from the cells corresponding to those of the ganglion crest which give origin to the spinal ganglia with the sensory components or dorsal roots of the spinal nerves. Otherwise between the cranial nerves and the spinal nerves there are many important differences. Each spinal nerve has a dorsal or sensory root, which springs from the cells of a spinal ganglion; a ventral or motor root, whose fibres are processes of the nerve-cells which are situated in the walls of the central system, and at their attachment to the surface of the cord the two roots are some distance apart. Only one of the (usually considered) twelve pairs of cranial
nerves corresponds at all closely with typical spinal nerves. This one is the trigeminus which possesses a sensory ganglionated root and near its attachment is accompanied by a small motor nerve, the masticator, which serves in very small part as a corresponding motor root of the trigeminus. But even in this case where the similarity between the cranial and spinal nerves is greatest, there are still points of anatomical difference, which if not essential are very obvious, for the so-called motor root joins not the whole but only with one branch of the sensory portion. The two are only slightly separated from each other at their attachment to the surface of the brain. All the other cranial nerves differ in a still more marked manner from typical spinal nerves. The first nerve is an afferent nerve whose cells of origin (olfactory ganglion) are scattered in the mucous membrane
of the nose, an organ of special sense, and its fibres are not collected together into a nerve-trunk, but pass, as a number of small bundles, through the lamina cribrosa of the ethmoid bone directly into the olfactory bulb. The optic nerve is also a nerve of special sense. Its fibres form a very distinct bundle, similar in appearance to an ordinary nerve, from which, however, it differs essentially, both with regard to structure and development; for, unlike an ordinary nerve, its connective tissue consists to a large extent of neurogha instead of ordinary connective tissue, and its component nerve-fibres are of much smaller calibre than those of an ordinary nerve. It represents the location of the original optic stalk, a diverticulum from the neural tube and it associates the retina (optic cup) , a bit of modified cor-
with an association tract of the central system than with an ordinary nerve.
The oculomotor, trochlear, abducens and hypoglossal nerves are purely motor nerves, and thus correspond only with the ventral roots of spinal nerves. The spinal accessory is also purely motor. Its fibres arise from the cells of the anterior horn of the spinal cord and from a nucleus of the medulla which represents a displaced portion of that horn, but they do not leave the surface of the spinal cord and brain in the usual situation of ventral roots. On the contrary, they emerge in a series of rootlets from the lateral funiculus of the cord on the dorsal side of the ligamentum denticulatum, and from the upward prolongation of this funiculus.
The cochlear and vestibular are nerves of special sense, and in some respects both correspond closely with the dorsal root of a typical spinal nerve, and the ganglia of both represent spinal ganglia, but their distribution is limited to the membranous labyrinth.
The vagus and glosso-pharyngeal nerves contain both motor and sensory fibres, but they differ from typical spinal nerves in that the motor fibres, in company with the sensory, issue from the postero-lateral sulcus of the medulla, and they are intimately intermingled, from their origin, with the sensory fibres, which latter arise from ganglia interposed in the trunks of the nerves and otherwise correspond with the fibres of the dorsal root of a typical spinal nerve.
Superficial attachments and origins. — It is customary to speak of the area where the nerve-fibres leave or enter the brain substance as the superficial attachments of the cranial nerves, and the groups of cells from which the fibres spring, and about which they terminate, as their nuclei of origin or termination, respectively.
THE OLFACTORY NERVES
The olfactory nerve-fibres are the central processes of the bipolar olfactory nerve cell-bodies situated in the olfactory region of the nasal mucous membrane. In man, the olfactory region comprises the epithelium upon the superior third of the nasal septum and that upon practically the whole of the superior nasal concha. The area is relatively small as compared with that of other mammals and, as in other mammals, is characterized by an increased thickness of the epithelium and a yellowish brown colour in the fresh. The peripheral processes of the olfactory cell-bodies (the olfactory gangUon) are short and extend only to the surface of the olfactory epithehum. As the central processes pass upward from their cells of origin they form plexuses in the mucous membrane, and from the upper parts of these plexuses, immediately below the lamiiia cribrosa of the ethmoid, about twenty filaments issue on each side. These filaments comprise the olfactory nerve. They are non-medullated. They pass upward, through the foramina in the lamina cribrosa, into the anterior fossa of the cranium in two rows, and after piercing the dura mater, the arachnoid, and the pia mater, they enter the inferior surface of the olfactory bulb. They contribute to the superficial stratum of nervefibres on the inferior surface of the olfactory bulb and end in the glomeruli, which are formed by the terminal ramifications of the olfactory nerve-fibres intermingled with the similar ramifications of the main dendrites of the large mitral cells which lie in the deeper part of the grey substance of the olfactory bulb.
The olfactory nerve-fibres are grey fibres, since they do not possess medullary sheaths, and they are bound together into nerves by connective-tissue sheaths derived from the pia mater, from the subarachnoid tissue, and from the dura mater. Prolongations of the subarachnoid space pass outward along the nerves for a short distance.
Central connections. — The olfactory impulses are transmitted by way of the peripheral processes of the olfactory neurones through the cell-bodies and the olfactory nerve-fibres and through the glomeruli to the mitral cells. Thence they are carried by the central processes (axones) of the mitral cells, which pass backward along each olfactorj' tract and its three olfactory strise (see Rhinencephalon, p. 864).
In lower vertebrates and recently in those mammals whose sense of smell is relatively much more developed than in man, three nerves have been found concerned with the olfactorj' apparatus:— ■(!) The olfactory nerve proper whose fibres, as noted above, are the central processes of
the nerve cell-bodies situated in the epithelium of the olfactory region of the nasal mucosa, and which terminate in the olfactory bulb; (2) The vomero-nasal nerve, whose fibres are the central processes of nerve cell-bodies situated in the epithelium of the vomero-nasal (Jacobson's) organ and which pass caudalward in the submucosa and upward to join the filaments of the olfactory nerve proper and which, in the dog, cat, rabbit, rat, etc., terminate in the accessory olfactory bulb — a small protuberance possessed by these animals on the postero-median aspect of the olfactory bulb proper; (3) The terminal nerve, a small plexiform nerve, which unlike the other two, is ganglionated.
In man, the vomero-nasal (Jacobson's) organ is rudimentary after birth and, therefore, the vomero-nasal nerve is not present, the only fibres for the vomero-nasal region being those of general sensibility from the trigeminus and sympathetic fibres common to the epithelium of the entire nasal fossa.
The terminal nerve has been recently described as present in the human foetus and it is mentioned here because of the expressed belief that it is present in the adult. From the observations recorded for human and rabbit foetuses and the adult dog and cat, the following description may be given: It is variably plexiform throughout its course. Its peripheral twigs are distributed to the mucosa of the nasal septum, some to the mucosa joining the olfactory region while other and larger twigs extend further forward and are distributed to mucosa of the vomero-nasal organ, accompanying and sharing in the distribution of the vomero-nasal nerve when this is present. Its central connections are in the form of two or three small roots which pass through the cribriform plate of the ethmoid bone in company with and mesial to the vomero-nasal nerve and then, still plexiform, extend caudalward over the infero-mesial aspect of the olfactory bulb and upon the olfactory peduncle or stalk (olfactory tract) beyond, a root often extending to near_the lamina terminalis and optic chiasma. The roots disappear in the mesial and infero-mesial aspect of the frontal portion of the brain at different localities caudal to the olfactory bulb and usually near the olfactory peduncle, but often one may disappear in the region corresponding to the anterior perforated substance of the adult human brain.
Numerous small groups of ganglion cells are found interposed along both the peripheral and intracranial course of the terminal nerve. A group, larger in size than the others and situated in the intracranial course of the nerve, is called the ganglion ierminale. The fibres of the nerve are non-medullated. Both the ganglion cells and the fibres of the nerve are described as having more the appearances characteristic of sympathetic neurones than of cranio-spinal. On the other hand, our conceptions of sympathetic neurones do not permit of their terminating within the central system except for the innervation of its bloodvessels. It may result that, instead of being an independent nerve as now claimed, the nervus terminalis is a part of the forward extension of the cephalic sympathetic, the larger ganglia and plexuses of which latter are well known, and that its neurones receive and convey impulses to the gland cells of the nasal mucosa and to the muscle of the blood-vessels of the mucosa and those supplying the infero-mesial part of the frontal end of the cerebrum.
The fibres of the optic nerve are the central processes of the ganglion cells of the retina. Within the ocular bulb they converge to the optic papilla, where they are accumulated into a rounded bundle, the optic nerve. The nerve thus formed pierces the chorioid and the sclerotic coats, and, at the back of the bulb, enters the orbital fat, in which it passes backward and medialward to the optic foramen. After traversing the foramen it enters the middle fossa of the cranium, and anastomoses with its fellow from the opposite side, forming the optic chiasma. It may, therefore, for descriptive purposes, be divided into four portions — the intra-ocular, the intra-orbital, the intra-osseous, and the intra-cranial. The total length of the nerve varies from forty-five to fifty millimetres.
The intra-ocular part is rather less than one millimetre in length. It passes backward from the optic papilla through the chorioid and through the sclerotic coats of the bulb. As it passes through the latter coat of the bulb in many separate bundles, the area it traverses has a cribriform appearance when the nerve is removed, and consequently is known as the lamina cribrosa sclerce.
The intra-orbital part of the nerve emerges from the sclerotic about three millimetres below and to the median side of the posterior pole of the bulbus, and it is about thirty millimetres long. It passes backward and medialward, surrounded by the posterior part of the fascia bulbi (Tenon's capsule) and by the orbital fat, to the optic foramen.
As it runs backward in the orbit it is in relation above with the naso-ciliary (nasal) nerve and the ophthalmic artery which pass obliquely from behind and laterally, forward and medialward across the junction of its posterior and middle thirds, and also in relation with the superior ophthalmic vein, the superior rectus muscle, and the upper branch of the oculo-motor nerve. Below it are the inferior rectus muscle, and the inferior division of the oculo-motor nerve. To its lateral side, near the posterior part of the orbit, are the ophthalmic artery, the ciliary ganglion, the abducens nerve,, and the external rectus muscle. The anterior two-thirds of this portion of the optic nerve are surrounded by the ciliary arteries and the ciliary nerves and it is penetrated on its
medial and lower aspect by the central artery of the retina. As it enters the optic foramen to become continuous with the intra-osseous part, it is in close relation with the ligaments of Lockwood and Zinn (annulus tendineus communis) and with the four recti muscles which arise from them.
The intra-osseous portion is from six to seven millimetres long. It lies between the roots of the small wing of the sphenoid and the body of that bone, and it is in relation below and laterally with the ophthalmic artery.
The intra-cranial portion, which is from ten to twelve millimetres long, runs backward and medialward, beneath the posterior end of the olfactory tract, and above the ophthalmic artery, the medial border of the internal carotid artery and the diaphragma sellse to the chiasma. From the chiasma to the central connections of the nerve, the path is known as the optic tract.
Middle palatine
The sheaths of the optic nerve. — The optic nerve receives a sheath from each of the membranes of the brain, and prolongations of the subdural and subarachnoid cavities also pass outward along it to the posterior part of the sclera.
The oculo-motor or third cranial nerve is a purely motor nerve. Each supplies seven muscles connected with the eye, two of which, the sphincter of the iris and cihary muscle, are within the ocular bulb. The remaining five are in the orbital cavity, and four of them — the superior, inferior, and medial recti and the inferior oblique — are attached to the bulb, while the fifth, the levator palpebrje superioris, is inserted into the upper eyelid.
The fibres of the oculo-motor nerve spring from their nucleus of origin situated in the grey substance of the floor of the cerebral aquteduct in the region of the superior quadrigeminate body (fig. 662). The cells of tliis nucleus are divided into two main groups, a superior and an inferior (fig. 663). The superior group includes two nuclei, a medial and a lateral. The latter, besides being lateral, is also somewhat dorsal to the former. The inferior group has been divided into five secondary nuclei, according to the eye-muscles the cells of each group innervate. Three of the five lie lateral to the others and somewhat dorsally, and of the remaining two, which are placed more medially, one encroaches upon the mid-line (nucleits mediaiis) and is con-
nerves of both sides.
It has been foimd, by the study of diseased conditions and by experiments with animals, that the centres of innervation of the eye-muscles suppUed by the nerve correspond to the above divisions of both the superior and inferior group of cells into a medial and lateral series. The relative position of the divisions of each group and the muscles they are thought to innervate are shown in the following diagram devised by Starr: —
As they leave their nucleus of origin in the mid-brain, the fibres of the oculomotor nerve form a series of fasciculi, which curve ventrally around and through the red nucleus and the medial part of the substantia nigra, to the oculo-motor sulcus on the medial surface of the cerebral peduncle, where they emerge in from six to fifteen small bundles which pierce the pia mater and collect into the trunk of the nerve. Immediately after its formation along the oculo-motor sulcus, the trunk of the nerve passes between the posterior cerebral and the superior cerebellar arteries, and, running downward, forward, and laterally in the posterior part of the cisterna basalis, it crosses the anterior part of the attached border of the tentorium cerebelli at the side of the dorsum sellse, and, piercing the arachnoid and the inner layer of the dura mater, it enters the wall of the cavernous sinus about midway between the anterior and posterior clinoid processes. Immediately after its entry into the wall of the sinus it lies at a higher level than the trochlear nerve, but the latter soon crosses on its lateral side and gets above it, and directly afterward the oculo-motor nerve divides into a smaller superior and a larger inferior branch (fig. 734). Before its division communications join it from the cavernous plexus of the sympathetic about the internal carotid artery, and from the ophthalmic division of the trigeminus. Both branches proceed forward, and the nasal branch of the trigeminus, which has passed upward, on the lateral side of the inferior branch of the oculomotor lies between them. At the anterior end of the cavernous sinus the two branches pass through the superior orbital (sphenoidal) fissure, between the heads of the lateral rectus muscle, and enter the orbital cavity. In the orbit, the superior branch hes between the superior rectus and the optic nerve; it supplies the superior rectus and then turns round the medial border of that muscle and terminates in the levator palpebrse superioris. The inferior branch runs forward, beneath the optic nerve, and divides into three branches which supply the inferior and medial recti and the inferior oblique.
The branch to the inferior oblique muscle is connected with the ciliary ganglion by a short thick offset, the short root of the ciliary ganglion, by mediation of the sympathetic neurones of which the oculo-motor nerve sends impulses to the ciliary muscle and the sphincter muscle of the iris. The inferior branch also gives some small twigs to the inferior rectus. The branches of the oculo-motor nerve, which supply the recti muscles, enter the muscles on their ocular surfaces, but the branch to the inferior oblique muscle enters the posterior border of that muscle.
Some of the fibres which spring from the medial portion of the oculo-motor nucleus do not pass into the nerve of the same side, but into that of the opposite side, and it is beheved that they are distributed to the opposite medial rectus muscle. Other fibres which arise from the nucleus descend in the medial longitudinal fasciculus and either terminate about the cells of the nucleus of the facial or join the facial nerve, in which they pass to the upper part of the orbicularis palpebrarum. The eye is opened by the oculo-motor and closed by the facial nerve. Central connections. — The nucleus of the oculo-motor is associated with the middle portion of the anterior central gyrus, the posterior end of the middle frontal gyrus and with the cortex about the visual area of the occipital lobe of the opposite side of the brain by the pyramidal fibres. It is probably associated with the cerebellum by the fibres in the superior cerebellar peduncles, with the superior calliculus, and with the sensory nuclei of the other cranial nerves by the medial longitudinal fasciculus. To produce the coordinated activities of the eye-moving muscles, it must be associated with the nuclei of the trochlear and abducens.
The fibres of each trochlear or fourth nerve (or patheticus) spring from the cells of a nucleus which lies in the grey substance of the floor of the cerebral aquseduct in hne with the oculo-motor nucleus, but in the region of the inferior quadrigeminate bodies. As the fibres pass from their origins they rim ventrally and laterally in the substance of the tegmentum for a short distance, then they curve medianward and dorsalward, and, in passing through the anterior end of the superior medullary velum they decussate totally with the fibres of the trochlear nerve
of the opposite side. After the decussation the fibres emerge from the surface of the superior medullary velum, at the side of the frenulum veli, usually in two small bundles, which pierce the pia mater and join together to form the slender trunk of the nerve. This trunk curves forward and ventralward to the base of the brain around the sides of the superior peduncle of the cerebellum and cerebral peduncle of the side opposite to that in which the nerve originates, running parallel with and between the superior cerebellar and posterior cerebral arteries. As it reaches the base of the brain behind the optic tract the nerve enters the cisterna basalis, in which it runs forward, immediately beneath or piercing the free border of the tentorium cerebelli, to the superior border of the petrous portion of the temporal bone, where it pierces the arachnoid and the dura mater and enters the posterior end of the lateral wall of the cavernous sinus. In the wall of the cavernous sinus it receives communications from the cavernous plexus of the sympathetic and bj' a small filament from the ophthalmic division of the trigeminus. It gradually ascends, as it passes forward in the lateral wall of the sinus, and, beyond the middle of the sinus, it crosses the lateral side of the trunk of the oculo-motor nerve and gains a higher position. At the anterior end of the sinus the nerve
enters the orbit above the lateral rectus and immediately turns medialward between the periosteum of the roof of the orbit and the levator palpebrae superioris. At the medial border of the roof it turns forward to its termination, and enters the orbital or superior surface of the superior oblique muscle to which its fibres are distributed.
The trochlear is peculiar in that — (1) it is the smallest of the cranial nerves; (2) it is the only nerve having its superficial attachment upon the dorsal aspect of the euoephalon; (3) it is the only cranial nerve whose fibres undergo a total decussation, and (4) in that it terminates in a muscle of the side of the body opposite that in which it has its origin. GaskeU has suggested that this latter condition has probably been brought about, phylogenetically, by the transference of the muscles which have carried their nerves with them. It should be remembered that most of the fibres arising from the medial group of the cells of the nucleus of the oculo-motor, cross the opposite side. This is thought to be especially true for those supplying the medial rectus muscle.
THE ABDUCENS
The abducens (or sixth nerve) on each side arises from the cells of a nucleus which lies in the grey substance of the floor of the fourth ventricle in the region of the inferior part of the pons. The nucleus is situated close to the middle line, ventral to the acoustic medullary strise and beneath the colliculus facialis and it is in direct linear series with the nuclei of the oculo-motor, trochlear and hypoglossal nerves. It is the third of the eye-moving nerves. The fibres which pass from the nucleus into the nerve run inferiorly and ventralward through the reticular formation, the trapezium, and the pyramidal fasciculi, and they emerge from the ventral surface of the medulla in the sulcus at the inferior border of the pons and the upper end of the pyramid of the medulla. From this superficial attachment the nerve runs upward and forward in the subarachnoid space between the pons and the basisphenoid and at the side of the basilar artery. A little below the level of the upper border of the petrous portion of the temporal bone it pierces the dura mater, passes beneath the petro-sphenoidal hgament, at the side of the dorsum sellte, and enters the cavernous sinus, in which it runs forward along the lateral side of the internal carotid artery. At the anterior end of the sinus it passes through the superior orbital (sphenoidal) fissure between the heads of the rectus lateralis, below the inferior branch of the oculo-motor nerve, and above the ophthalmic vein. In the orbit it runs forward on the inner or ocular surface of the rectus lateralis, and finally it pierces this muscle and terminates upon its fibres.
plexus of the sympathetic and from the ophthalmic nerve.
All the fibres arising in the nucleus of the sixth nerve do not pass into the sixth nerve. Some of them ascend in the medial longitudinal fasciculus of the same and opposite sides, and terminate about cells of the medial group of the nucleus of the oculo-motor nerve, by which the impulses are conveyed to the opposite medial rectus muscle. Thus impulses reaching the abducens nucleus can throw into simultaneous action the lateral rectus of the same side and the medial rectus of the opposite side, and thus turn both ej'es in the same direction.
Central connections. — The nucleus of the abducens receives impulses from the anterior central gyrus of the opposite side by the pj'ramidal fibres, and it is associated with the sensory nuclei of other nerves by way of the medial longitudinal fasciculus, and that of the trigemiuus especially through the reticular formation.
THE TRIGEMINUS
The trigeminus is the largest of the cranial nerves with the exception of the optic. It is usually described as the fifth cranial nerve and as possessing both a sensory and a motor root. For reasons already given, the "motor root" is here described separately and given the separate name, masticator nerve. The fibres of the trigeminus, which are all sensory, spring from the cells of the semilunar (Gasserian) ganglion, which corresponds with the ganglion of the dorsal root of a spinal nerve, and they enter the brain stem through the side of the anterior third of the pons.
BRANCHES OF THE TRIGEMINUS 935
The semilunar (Gasserian) ganglion is a semilunar mass which lies in Meckel's cave, a cleft in the dura mater above a depression in the medial part of the upper surface of the petrous portion of the temporal bone. The convexity of the ganglion is turned forward, and from it three large nerves, the ophthalmic, the maxillary, and the mandibular, are given off. From the concavity, which is directed backward, springs the root of the nerve. The medial end of the ganglion is in close relation with the cavernous sinus and the internal carotid artery at the foramen lacerum, and the lateral end lies to the medial side of the foramen ovale. The surfaces of the ganglion are striated, due to bundles of fibres traversing them. The upper surface is separated by the dura mater from the temporal lobe of the brain, and the lower rests upon the masticator nerve and the outer layer of dura mater upon the petrous portion of the temporal bone.
The fibres of the trigeminus root as they leave the semilunar (Gasserian) ganglion, form from thirty to forty fasciculi which are bound together into a flat band, from six to seven millimetres broad, which passes backward over the upper border of the petrous portion of the temporal bone and below the superior petrosal sinus into the posterior fossa of the cranium. In the posterior fossa it runs backward, medialward, and downward, and passes into the pons through its continuation into the middle peduncle of the cerebellum. In the tegmentum of the pons region, the fibres bifurcate into ascending and descending branches which terminate about the cells of the nucleus of termination of the trigeminus. This nucleus, large at the level of the entrance of the root, has tapering superior and inferior e.xtremities. The inferior extremity of the nucleus, which is much the longer, descends as low as the upper portion of the spinal cord and the fibres of the root terminating about the cells of this extremity are known as the spinal tract of the trigeminus.
Central connections. — The nuclei of termination of the trigeminus send impulses to the somaesthetic area of the cortex of the opposite side by the fibres of the medial lemniscus (fillet) and, for reflex actions, to the motor nuclei of other cranial nerves by the medial longitudinal fasciculus and by fascicuU propri in the reticular formation of the same, and opposite sides.
The main branches of the trigeminus, given off by the front side of the semilunar ganglion, are three in number (ophthalmic, maxillary, and mandibular) , each of which is referred to as a nerve and each of which is purely sensory, though the third branch, or mandibular nerve, is joined by the fibres of the masticator nerve which is motor.
The ophthalmic nerve, the first division of the trigeminus, is the smallest of the three branches which arise from the semilunar (Gasserian) ganglion. It springs from the medial part of the front of the ganglion and passes forward, in the lateral wall of the cavernous sinus, where it lies below the trochlear nerve and lateral to the abducens nerve and the internal carotid artery (fig. 734). A short distance behind the superior orbital (sphenoidal) fissure the nerve divides into three terminal branches — the frontal, lacrimal, and naso-ciliary (nasal) nerves. They pierce the dura mater, which closes the fissure, and pass forward into the orbit. Before its division the ophthalmic nerve receives filaments from the cavernous plexus of the sympathetic and it gives off, soon after its origin, a tentorial (recurrent meningeal) branch which runs backward, in close association with the trochlear nerve, and ramifies between the layers of the tentorium cerebelli. Further forward three branches spring from the ophthalmic nerve which contribute sensory fibres to the oculo-motor, trochlear, and abducens nerves.
The terminal branches. — (a) The frontal nerve is the largest terminal branch. It pierces the dura mater and passes into the orbit through the superior orbital (sphenoidal) fissure, above the rectus lateralis and a little below and to the lateral side of the trochlear nerve. In the orbit it runs forward, between the levator palpebrse superioris and the periosteum, and breaks up into three branches, the supra-orbital, frontal proper, and supratrochlear.
The supra-orbital nerve, the largest of the three branches, leaves the orbit at the supraorbital notch (fig. 734). As it passes thi-ough the notch it gives off a small branch which enters the bone and supphes the diploe and the mucous membrane of the frontal sinus. Its terminal branches give twigs to the pericranium and to the skin of the scalp, the upper ej-eUd, the frontal
The supratrochlear branch runs forward and medialward toward the upper and medial angle of the orbit, where it passes above the pulley of the superior obhque muscle, pierces the palpebral fascia, and ascends to the lower and middle part of the forehead, accompanied by the frontal artery (fig. 734). Before it leaves the orbit it sends a branch downward behind or in front of the pulley of the obliquus superior which joins with the infratrochlear nerve, and as it leaves the orbit it gives off filaments to supply the skin and conjunctiva of the medial third of the upper eyelid. Its terminal branches pierce the orbicularis and frontalis, and, as they pass to the skin of the forehead, they communicate with branches of the facial nerve.
(b) The lacrimal nerve [n. lacrimalis] is the smallest of the three branches of the ophthalmic division. It passes through the superior orbital (sphenoidal) fissure lateral to and slightly below the frontal nerve, and is directed forward and lateral-
ward, along the upper border of the rectus lateralis to the lacrimal gland (fig. 734) . On the lateral wall of the orbit it receives a small branch from the zygomatic nerve (the orbital branch of the maxillary nerve). This branch brings to the lacrimal nerve secretory fibres for the lacrimal gland. A small twig passes beyond the gland, pierces the palpebral fascia, supplies filaments to the conjunctiva, and is then distributed to the integument at the lateral angle of the eye and to the skin over the zygomatic process of the frontal bone.
(c) The naso-ciliary (nasal) nerve enters the orbit between the two heads of the rectus lateralis and between the superior and inferior branches of the oculo-motor nerve. In the orbit it lies at first lateral to the optic nerve, but, as it runs obliquely forward and medialward to the medial wall of the orbital cavity, it crosses above the optic nerve and between it and the rectus superior, and near the border of the rectus medialis it divides into its terminal branches, the chief of which are the infratrochlear and anterior ethmoidal nerves (fig. 734). In addition to those received from the cavernous plexus before the division of the ophthalmic nerve ,
Its several branches are: (i) The long root of the ciliary ganglion which is given off at the superior orbital (sphenoidal) fissure. It is a slender filament which runs forward on the lateral side of the optic nerve to the superior and posterior part of the ciliary ganglion (fig. 734).
(ii) The long ciliary nerves, usually two in number, which arise from the naso-cihary nerve as the latter is crossing above the optic nerve. They run forward, on the medial side of the optic nerve, pierce the sclerotic, and are distributed with the lower set of short ciliary nerves (fig. 734). The long root of the cihary ganglion and the long ciUary nerves carry sensory fibres which belong to the naso-ciliary nerve proper, most of which merely pass through the ganglion, and it carries sympathetic fibres, added to it, most of which may terminate about the cell-bodies of the ganglion.
(iii) The posterior ethmoidal (spheno-ethmoidal) branch springs from the posterior border of the naso-ciUary nerve near the upper border of the rectus medialis. It passes through the posterior ethmoidal canal and is distributed to the mucous membrane of the posterior ethmoidal cells and the sphenoidal sinus.
(iv) The infratrochlear nerve passes forward between the obhquus superior and the rectus medialis, and under the pulley of the former muscle divides into two branches: — The superior palpebral branch helps to supply the eyehds with sensory fibres and usually anastomoses with the supratrochlear nerve. The inferior palpebral branch is distributed to the lacrimal sac, the conjunctiva and skin of the medial part of the upper eyehd, the caruncle, and the skin of the upper part of the side of the nose.
(v) The anterior ethmoidal (distal part of the nasal) nerve, passing forward and medialward between the obhquus superior and the rectus medialis, leaves the orbit through the anterior ethmoidal foramen, accompanied by the anterior ethmoidal vessels, and enters into the anterior fossa of the cranium (fig. 734). It then crosses the lamina cribrosa of the ethmoid, lying outside the dura mater, which separates it from the olfactory bulb, and descends into the nasal fossa through the ethmoidal fissure, a slit-like aperture at the side of the crista galli. In the submucosa of the nasal fossa it terminates by dividing into two sets of anterior nasal branches: the internal nasal branches and the external nasal branch (fig. 732).
The internal nasal branches divide into the medial nasal branches (the septal branches of the nasal nerve), which run downward and forward on the upper and front part of the septum, and the lateral nasal branches (the external terminal branch of the nasal nerve), which give twigs to the anterior extremities of the superior and middle nasal conchae (turbinated bones), and to the mucous membrane of the lateral wall of the nose (fig. 732).
The external nasal branch (the anterior terminal branch of the nasal nerve) runs downward in a groove on the inner surface of the nasal bone. It pierces the wall of the nose between the nasal bone and the upper lateral cartilage, and supphes the integument of the lower part of the dorsum of the nose as far as the tip.
size between the ophthalmic and mandibular nerves.
It springs from the middle of the anterior border of the semilunar (Gasserian) ganglion and runs forward in the lower and outer part of the lateral wall of the cavernous sinus (fig. 735). Leaving the middle fossa of the cranium, by passing through the foramen rotundum, it enters the pterygo-palatine (spheno-maxillary) fossa (fig. 734), where it is joined by twigs with the spheno-palatine ganglion; then, changing its name, it passes forward, as the infra-orbital nerve, through the inferior orbital (spheno-maxillary) fissure into the infra-orbital sulcus in the floor of the orbit; continuing forward it traverses the infra-orbital canal accompanied by the infra-orbital artery, and appears in the face, beneath the levator labii superioris (quadratus) and above the levator anguli oris (caninus) where it divides into four sets of terminal branches which anastomose more or less freely with branches of the facial nerve to form the infra-orbital plexus.
Branches. — The branches of the maxillary nerve are — (a) branches given off in the middle fossa of the cranium; (6) branches given off in the pterygo-palatine (spheno-maxillary) fossa; (c) branches given off in the infra-orbital sulcus and canal; and (d) terminal branches.
(a) The middle (recurrent) meningeal branch, given off in the middle fossa of the cranium, breaks up into numerous branches which supply the dura mater with sensory fibres, reinforce the sympathetic plexus on the middle meningeal artery, and anastomose with the spinous nerve (the recurrent branch of the mandibular nerve).
(b) The branches given off in the pterygo-palatine (spheno-maxillar}^ fossa are the spheno-palatine nerves, the zygomatic branch of the maxillary nerve, and the posterior superior alveolar nerves.
The spheno -palatine nerve has two or three branches which descend in the pterygopalatine fossa and give a small part of their fibres to the spheno-palatine (Meckel's) ganghon (fig. 735), the larger part of their fibres passing tlirough the ganghon into its orbital, nasal, and palatine branches. (See Spheno-p.\l.\tine Ganglion, p. 962.)
The zygomatic (orbital or temporo-malar) branch, given off from the upper surface of the maxiUary nerve, passes forward and lateralward, and, at the end of the inferior orbital (sphenomaxillary) fissure, passes through it into the orbit and divides into two branches, facial and temporal.
The zygomatico -facial (malar) branch runs forward, passes through a zygomatico-orbital foramen, then thi-ough the zygomatico-facial (malar) foramen, pierces the orbicularis palpebrarum, communicates with the zygomatic (malar) branch of the facial nerve, and supplies the skin of the prominence of the cheek. The zygomatico -temporal (temporal) branch runs upward in a groove in the lateral wall of the orbit, passes through a zygomatico-orbital foramen, then through the zygomatico-temporal (spheno-malar) foramen, and enters the temporal fossa. It turns around the anterior border of the temporal muscle, pierces the deep layer of the temporal fascia, and runs backward for a short distance in the fat between the superficial and deep lamellae, then, turning lateralward, it pierces the superficial lamellae about an inch above the zygoma, anastomoses with the temporal branch of the facial nerve, and supphes the skin of the anterior part of the temporal region.
The infra-orbital nerve, that part of the maxiUary nerve lying distal to the sphenopalatine ganghon, enters the orbit through the inferior orbital (spheno-maxiUary) fissure, accompanied by the infra-orbital artery, and with it passes through the infra-orbital canal (fig. 735) to the face, where it divides into four sets of terminal branches, some of which, by anastomoses with the branches of the facial nerve, form the infra-orbital plexus.
Three sets of superior alveolar nerves arise from the maxillary and the infra-orbital nerves, namely, the posterior superior alveolar branches, the middle superior alveolar branch, and the anterior superior alveolar branches.
Middle superior alveolar branch
The posterior superior alveolar (dental) nerves are usually two in number, but sometimes arise by a single trunk. They pass downward and lateralward through the pterygo-maxillary fissure into the zygomatic fossa, where they give branches to the mucous membrane of the gums and the posterior part of the mouth; then they enter the posterior alveolar (dental) canals and unite with the other alveolar branches to form the superior dental plexus, through which they give branches to the roots and pulp cavities of the molar teeth and to the mucous membrane of the maxillary sinus (fig. 735).
(i) The middle superior alveolar (dental) nerve leaves the infra-orbital nerve in the posterior part of the inlVa-orliital sulcus, and, pa.ssing downward and forward in a canal in the maxilla, it divides into terminal branches that anastomose with the other alveolar branches to form the superior dental plexus. Through the plexus it supplies the bicuspid teeth and gives branches to the mucous membrane of the maxillary sinus and also to the gums (fig. 735).
THE MANDIBULAR NERVE 939
(ii) The anterior superior alveolar (dental) nerve is the largest of the superior alveolar nerves. It is given off by the infra-orbital nerve in the anterior part of the infra-orbital canal, and passes downward in a bony canal in the anterior wall of the maxilla. After uniting with the other alveolar nerves to form the superior dental ple.xus, it supplies the canines and the incisors and gives branches to the mucous membrane of the maxillary sinus and the gums (fig. 735). It also gives off a nasal branch which enters the nasal fossa through a small foramen, and supphes the mucous membrane of the anterior part of the inferior meatus and the adjacent part of the floor of the nasal cavity.
(iii) The superior dental plexus is formed in the bony alveolar canals by the three superior alveolar nerves. It is convex downward and anastomoses across the mid-line with the corresponding plexus of the other side (fig. 735). From it arise the superior dental branches supplying the superior canines and incisors, superior gingival branches supplying the gums, and also branches to the mucous membrane of the maxiUary sinus and to the bone. On the plexus are two gangliform enlargements, one, called the ganglion of Valentine, situated at the junction of the middle and the posterior branches, and the other, called the ganglion of Bochdalek, at the junction of the middle and anterior branches.
aose, and then turn ujnvard to supply the skin of the vestibule of the nose.
The superior labial branches, three or four in number, as a rule are larger than the palpebral and nasal branches. They pass downward to supply the skin and mucous membrane of the upper Up and the neighbouring part of the cheek.
The mandibular division is the largest of the three divisions of the trigeminus (figs. 736 and 740). As a nerve, it is usually described as formed by the union of two distinct nerves, namely, the entire masticator nerve and the large bundle of sensory fibres derived from the semilunar (Gasserian) ganglion which pass peripherally as the third division of the trigeminus. These two nerves remain separate until they pass through the foramen ovale and then unite immediately outside the skull to form a large trunk which almost directly after its formation divides into a small anterior and a larger posterior portion. The trunk is situated between the pterygoideus externus, laterally, and the otic ganglion and the tensor palati medially. In front of it is the posterior border of the pterygoideus internus, and behind it, the middle meningeal artery. Two branches arise from the trunk of the nerve before its division, namely, the spinous (recurrent) nerve and the nerve to the pterygoideus internus.
The spinous (recurrent) nerve, after receiving a vasomotor filament from the otic ganglion, enters the cranium through the foramen spinosum, accompanying the middle meningeal artery, and divides into an anterior and a posterior branch. The anterior branch communicates with the meningeal branch of the maxillary division of the trigeminus, furnishes filaments to the dura mater, and ends in the osseous substance of the great wing of the sphenoid. The posterior branch traverses the petrosquamous suture and ends in the Uning membrane of the mastoid ceUs.
The fibres going to form the neriie to the internal pterygoid muscle are almost wholly motor fibres and therefore comprise a branch of the masticator nerve and are described as such under the description of the masticator (fig. 737).
The anterior portion of the mendibular nerve is smaller than the posterior and is chiefly composed of motor fibres which form branches of the masticator nerve and supply the muscles of mastication, the temporalis, masseter, and pterygoideus externus. Practically all of the sensory fibres of the anterior portion (fibres of the mandibular nerve proper) form the buccinator (long buccal) nerve. The latter is accompanied, in the first part of its course, by a small strand of motor or masticator fibres which leaves it to end in the anterior part of the temporal muscle.
The buccinator (long buccal) nerve, entirely sensory, passes between the two heads of the external pterygoid muscle and runs do\\Tiward and forward under cover of or through the anterior fibres of the temporahs to the cheek (fig. 736). As it passes forward it emerges from under cover of the anterior border of the masseter and lies on the superficial surface of the buccinator, where it interlaces with the buccal branches of the facial nerve and gives off filaments to supply the superjacent skin; finally it pierces the buccinator and supphes the mucous membrane on its
inner surface as far forward as the angle of the mouth. The fibres of the anterior deep temporal nerve, a branch of the masticator, are frequently associated with the buccinator until the latter has passed between the heads of the external pterygoid; then the anterior deep temporal nerve separates from the buccinator and passes upward on the lateral surface of the upper head of the external pterygoid.
The posterior portion of the mandibular nerve divides into three large branches. Two of these, the lingual and the auriculo-temporal nerves, are exclusivelysensory; the third, the inferior alveolar (dental) nerve, contains a strand of motor fibres, the mylo-hj^oid nerve, which comprise a branch of the masticator nerve.
The lingual nerve is the most anterior branch of the mandibular nerve (figs. 736, 743) . It lies in front and to the medial side of the inferior alveolar (dental) nerve and descends at first on the medial side of the pterygoideus externus, then between the pterygoideus internus and the ramus of the mandible to the posterior part of the mylohyoid ridge, where it passes off the anterior border of the pterygoideus internus; at this point it is situated a short distance behind the last
After leaving the pterygoideus internus it crosses the fibres of the superior constrictor, which are attached to the mandible, and turns forward toward the tip of the tongue, crossing the lateral surfaces of the styloglossus, hyoglossus, and genioglossus. In its com-se across the hyoglossus it lies first above, then to the lateral side of, and finally below Wharton's duct, and as it ascends on the genioglossus it lies on the medial side of the duct.
Communications and branches. — While it is on the medial side of the pterygoideus externus the lingual nerve is joined, at an acute angle, by the chorda tympani (figs. 736, 743), a branch of the glosso-palatine nerve, and as it hes between the ramus of the mandible and the pterygoideus internus it is connected by a branch with the inferior alveolar (dental) nerve, and gives off one or two small branches, the rami isthmi faucium, which are ditributed as sensory fibres to the tonsil and the mucous membrane of the posterior part of the mouth (fig. 743).
While it is above the duct it gives a branch, which contains many sensory and visceral motor chorda tympani fibres, to the submaxillary ganghon (.seep. 963), and it receives branches, chiefly sympathetic, from that ganglion. A little further forward it is connected by one or two branches, which run along the anterior border of the hyoglossus, with the hypoglossal nerve
(fig. 743). It then gives off the sublingual nerve, which runs forward to supply the subHngual gland and the neighbouring mucous membrane (fig. 74.3). Its terminal (lingual) branches are derived chiefly from the glosso-palatine nerve. They pierce the muscular substance of the tongue and are distributed to the mucous membrane of its anterior two-thu-ds. They interlace with similar branches of the other side and with branches of the glosso-pharyngeal nerve.
The inferior alveolar (dental) nerve is the largest branch of the posterior portion of the mandibular nerve. It commences on the medial side of the external pterygoid muscle and descends to the interval between the spheno-mandibular ligament and the ramus of the mandible, where it receives one or two communicating branches from the lingual nerve. Opposite the middle of the medial surface of the ramus it enters the mandibular (inferior dental) canal, accompanied by the inferior alveolar (dental) artery, which lies in front of the nerve, and it runs downward and forward through the ramus and the body of the mandible (fig. 736). At the mental foramen it divides into two parts, one of which, the mental nerve, passes out through the mental foramen, the other, commonly called the incisive branch, continues forward in the canal, and supplies, through the inferior dental plexus, the inferior canine and incisor teeth and the corresponding regions of the gums.
Branches. — ^The branches of the inferior alveolar (dental) nerve are branches forming the inferior dental plexus, and the mental branch. A bundle of motor fibres, the mylohyoid nerve, a branch of the masticator nerve, is given off just before the inferior alevolar nerve enters the mandibular canal.
The inferior dental plexus is formed by a series of branches which communicate with one another within the bone, giving rise to a fine network. From this plexus two sets of branches are given off: — the inferior dental branches, corresponding in number to the roots of the teeth, enter the minute foramina of the apices of the roots and end in the pulp; the second set, the inferior gingival branches, supply the gums.
It communicates, near its exit from the bone, with branches of the facial nerve, and then divides into three branches. The smallest branch, turning downward, divides into several twigs, the menial branches, which supply the integument of the chin. _ The other two, inferior labial branches, pass upward, diverging as they ascend, and divide into a number of twigs. The stoutest twigs ramify to the mucous membrane which lines the lower hp. Other twigs are distributed to the integument and fascia of the hp and chin.
The auriculo -temporal nerve usually arises from the posterior portion of the mandibular nerve by two roots which embrace the middle meningeal artery and unite behind it to form the trunk of the nerve. The trunk passes backward on the medial aspect of the pterygoideus externus, and between the spheno-mandibular ligament and the temporo-mandibular articulation, lying in close relation with the capsule of the joint. Behind the joint it enters the upper part of the parotid gland, through which it turns upward and lateralward. It emerges from the upper end of the gland, crosses the root of the zygoma close to the posterior border of the superficial temporal artery, and divides into auricular and temporal terminal branches at the level of the tragus of the pinna (fig. 736) .
Communications. — (a) Each of the two roots of the nerve receives a communication from the otic ganglion containing fibres derived from the glosso-pharyngeal nerve. These fibres have passed from the glosso-pharyngeal through the tympanic plex-us and the smaU superficial petrosal nerve and through the otic ganglion.
dibular joint, given off as the nerve lies on the medial side of the capsule.
(6) Branches to the external auditory meatus. Two branches, as a rule, are given off in the parotid gland. They enter the meatus by passing between the cartilage and the bone and supply the upper part of the meatus, the membrana tympani by a fine branch, and occasionally the lower branch gives twigs to the skin of the lobule of the pinna.
(c) Parotid branches are distributed to the substance of the parotid gland. Sensory or trigeminal fibres for the gland spring either directly from the nerve or from the communicating branches previously given by it to the glosso-palatine nerve. The parotid branches also contain filDres derived from the glosso-pharyngeal nerve which pass successively through its tympanic branch, the tympanic plexus, the small superficial petrosal nerve, the otic ganglion, and the communicating twigs from the otic ganglion to the roots of the auriculo-temporal nerve. The parotid branches are later again mentioned as concerned chiefiy with the ganglialed cephalic plexus.
The masticator nerve (motor root or portio minor of trigeminus) . The fibres of the masticator nerve spring from two nuclei, a slender upper or mesencephalic nucleus and a clustered lower or chief nucleus. The fibres arising in the mesencephalic nucleus descend along the lateral aspect of the nucleus to the pons as the descending or mesencephalic root;* here they join the fibres from the chief motor nucleus and issue with them from the side of the pons in from six to ten root filaments. These blend to form the nerve, which is from one and a half to two millimetres broad. At the point where it emerges from the pons the nerve is in front of and ventral to the root of the trigeminus and it is separated from the latter by a few of the transverse fibres of the pons which constitute the lingula oj Wrisberg. From its superficial exit from the pons, the masticator nerve passes upward, lateralward, and forward in the posterior fossa of the cranum, and along the medial and anterior aspect of the trigeminus, to the mouth of Meckel's cave. In this cavity it runs lateralward below the semilunar (Gasserian) ganglion to the foramen ovale, through which it passes to join the mandibular division of the
with mastication.
Central connections. — The nuclei of origin of the masticator nerve are connected with the lower part of the somaesthetic area of the cerebral cortex of the opposite side by the p}Tamidal fibres descending in the genu of the internal capsule, and they are associated with the sensory nuclei of other cranial nerves through the reticular formation and by the medial longitudinal fasciculus.
Branches. — Almost immediately after joining the trunk of the mandibular nerve, most of the fibres of the masticator leave it to form the greater part of the so-called anterior portion of the mandibular. However, one branch of masticator fibres, the nerve to the internal pterygoid muscle, is given off from the mandibular just before its division into anterior and posterior portions. The masticator
branches derived from the anterior portion are the deep tem-poral nerves, the masseteric nerve, and the nerve to the external -pterygoid. One branch, the mylo-hyoid nerve, is carried in the posterior portion of the mandibular and is given off from its inferior alveolar branch.
The nerve to the internal pterygoid passes under cover of a dense layer of fascia derived from an expansion of the ligamentum pterygo-spinosum, and enters the deep surface of the muscle. Near its commencement this nerve furnishes a visceral motor root to the otic ganglion, and small twigs to the tensor tympani and tensor palati.
The deep temporal nerves, usually two in number, posterior and anterior, pass between the bone and the upper border of the external pterygoid muscle, and turn upward around the infratemporal crest of the sphenoid bone to end in the deep surface of the temporalis (fig. 736). The posterior of the two often arises in common with the masseteric nerve. The anterior is frequently associated with the buccinator (long buccal) nerve till the latter has passed between the two heads of the pterygoideus externus. There is frequently a third branch, the medius, which passes lateralward above the pterygoideus externus, and turns upward close to the bone to enter the deep surface of that muscle. A small strand of masticator fibres accompanies the buccinator nerve to enter and end in the anterior part of the temporal muscle.
The masseteric nerve, which frequently arises in common with the posterior deep temporal nerve, passes between the bone and the pterygoideus externus, and accompanies the masseteric artery through the notch of the mandible to be distributed to the masseter (fig. 736). It is easily traced through the deeper fibres nearly to the anterior border of the masseter. As it emerges above the pterygoideus externus it gives off a twig to the temporo-mandibular articulation.
The nerve to the external pterygoid, after a course of about 3 mm. (an eighth of an inch), divides into twigs which enter the deep surface of the two heads of the muscle. It is usually adherent at its origin to the buccinator nerve.
The mylo-hyoid branch, carried in the posterior portion of the mandibular nerve, is given off immediately before the inferior alveolar (dental) nerve enters the mandibular (inferior dental) canal. It pierces the lower and back part of the spheno-mandibular ligament and runs downward and forward in the mylo-hyoid groove between the mandible on the lateral side, and the internal pterygoid muscle and the lateral surface of the submaxillary gland on the medial side. In the anterior part of the digastric triangle it is continued forward between the anterior part of the submaxillary gland and the mylo-hyoideus, and it breaks up into branches which supply the mylo-hyoideus and the anterior belly of the digastric (fig. 736).
The facial or seventh nerve is purely motor. It is accompanied a short distance by a bundle usually called its sensory root or the intermediate nerve. This latter, however, on the Ijasis of its origin, distribution, and mixed instead of sensory character, is described separately below as the glosso-palatine nerve. It is smaller than the facial, is fused to the trunk of the facial and the ganglion giving rise to its sensory fibres is situated upon the external genu of the facial (figs. 738 and 741).
The fibres of the facial nerve (fig. 738) spring from a nucleus of cells situated laterally in the reticular formation at the level of the lower pons, dorsal to the superior olive, and between the root fibres of the abducens nerve and the laterally placed spinal tract of the trigeminus. From this nucleus the fibres of the nerve pass medially and dorsalward to the floor of the fourth ventricle and, just under the floor, they turn anteriorly, passing dorsal to the nucleus of the abducens (fig. 653, p. 827). At the anterior end of this nucleus they turn sharply ventralward and lateralward, and at this point it is claimed that fibres descending in the near-by medial longitudinal fasciculus from the nucleus of the oculo-motor nerve of the same side become intermingled with the fibres of the facial nerve and pass outward with them. This, however, is uncertain. Continuing ventralwai'd through the reticular formation the fibres of the facial emerge from the brain-stem at the inferior border of the pons, lateral to the superficial attachment of the abducens. At the point of its emergence, the facial nerve pierces the pia mater, from which it receives a sheath, and then proceeds forward and lateralward in the posterior fossa of the cranium to the internal auditory meatus, which it enters in company with the glosso-palatine nerve and with the cochlear and vestibular nerves. As it lies in the meatus it is situated above and in front of the latter nerves, from which it is separated by the glosso-palatine, and it is surrounded, together with these three nerves, by sheaths of both the arachnoid and the dura mater and by prolongations of the subarachnoid and sub-dural spaces. While it is still in the meatus it blends with the glosso-palatine and thus the combined trunk is formed. At the outer end of the meatus the trunk pierces
the arachnoid and the dura mater and enters the facial canal (aqueduct of Fallopius), in which it runs forward and slightly lateralward to the hiatus Fallopii, where it makes an angular bend, the external genu [geniculum], around the anterior boundary of the vestibule of the inner ear; this bend is enlarged by the adhesion of the geniculate ganglion (of the glosso-palatine) upon its anterior border. From the geniculum the facial nerve runs backward in the facial canal along the lateral wall of the vestibule and the medial wall of the tympanum, above the fenestra vestibuli (ovalis), to the junction of the medial and posterior walls of the tympanic cavity; then, bending downward, it descends in the posterior wall to the stylo-mastoid foramen. As soon as it emerges from the stylo-mastoid foramen it turns forward around the lateral side of the base of the styloid process.
Small deep petrosal nerve
and plunges into the substance of the parotid gland, where it divides into its cervico-facial and temporo-facial terminal divisions. Before its terminal divisions, the nerve gives off three, and sometimes four, small branches: one, the nerve to the stapedius muscle, before it leaves the skull, the others after it leaves the skull.
The nerve to the stapedius is given off from the facial nerve as it descends in the posterior wall of the tympanum behind the pyramidal eminence. It is stated that filaments are also given off from the facial to the auditory artery (probably visceral motor from the glosso-palatine) while the nerve is passing through the internal auditory meatus.
After it leaves the skull the facial nerve gives off two or three coll terai branches and its two terminal divisions, the temporo-facial and cervico-facial. The collateral branches are the posterior auricular nerve, a branch to the posterior belly of the digastric, and sometimes a lingual branch.
(1) The posterior auricular nerve is the first branch of the extracranial portion of the facial nerve. It passes between the parotid gland and the anterior border of the sterno-mastoid muscle and runs upward in the deep interval between the external auditory meatus and the mastoid process. In this situation it communicates with the auricular branch of the vagus. It supplies the auricularis posterior, sends a slender twig upward to the am-ioularis superior, and ends in a long slender branch, the occipital branch, which passes backward to supply the occipitalis muscle. It also receives filaments from the small occipital and great auricular nerves, and supplies the intrinsic muscles of the auricle (pinna).
(2) The nerve to the posterior belly of the digastric arises from the facial nerve close to the stylo-mastoid foramen and enters the muscle near its centre, or sometimes near its origin. It usually gives off two branches: the nerve to the stylo-hyoid, which sometimes arises directly from the facial nerve and passes to the upper part of the muscle that it supplies, and the anastomotic branch, which joins the glosso-pharyngeal nerve below its petrous ganglion.
(3) The lingual branch, first described by CruveiUiier, is not commonly present. It arises a little below the nerve to the stylo-hyoideus and runs downward and medialward to the base of the tongue. In its course it passes to the medial sides of the stylo-glossus and stylo-pharyn-
geus, and runs downward along the anterior border of the latter muscle to the wall of the pharynx. It pierces the superior constrictor, insinuates itself between the tonsil and the anterior piUar of the fauces, and it is stated that it gives filaments to the base of the tongue and to the stylo-glossus and glosso-palatinus (palato-glossus) muscles.
The terminal divisions. — In the substance of the parotid gland the two terminal divisions of the facial nerve he superficial to the external carotid artery and to the posterior facial (temporo-maxillary) vein. The way in which these terminal divisions give off their branches varies much in different subjects and often on the opposite sides of the same subject. One of the more common forms is here described.
The temporo-facial or upper division runs upward and forward, and, after receiving communicating twigs from the auriculo-temporal nerve, gives off temporal and zygomatic (malar) branches. The cervico -facial or lower division runs downward and forward, receives branches from the great auricular nerve, and
Superior cervical sympathetic ganghon
gives off — (1) buccal branches, comprising what have been called infraorbital and buccal branches; (2) the marginal mandibular (supra-mandibular) branch; and (3) the ramus colli (infra-mandibular branch). These branches from the two terminal divisions anastomose freely to form the parotid plexus (pes anserinus).
The temporal branches passing upward communicate freely with each other and with the zygomatic branches. They also communicate with the zygomatico-temporal branch of the zygomatic nerve (the orbital branch of the maxillary nerve) and with the supra-orbital nerve. They supply the frontalis, orbicularis oouli, corrugator supercilii, and auricularis anterior and superior (fig. 740).
The zygomatic (malar) branches passing upward and forward, communicate with the buccal branches of the facial nerve; with the zygomatico-facial branch of the zygomatic nerve (the orbital branch of the maxillary nerve) ; with the supraorbital and lacrimal branches of the ophthalmic nerve, and with the palpebral twigs of the maxillary. They supply both ej'ehds, the orbicularis oculi, and tlie zygomaticus (fig. 740).
The buccal (infra-orbital and buccal) branches arise sometimes from the lower terminal division and sometimes from both the upper and the lower terminal divisions. The buccal branches, passing forward upon the masseter and underneath the zygomaticus and quadratus labii superioris, interlace with the zygomatic and marginal mandibular (supra-mandibular) branches of the facial nerve, with the buccinator (long buccal) branch of the trigeminus, and with the terminal branches of the maxillary nerve, forming with the last-named nerve the infraorbital plexus. They supply the zygomaticus, risorius, quadratus labii superioris, caninus.
The marginal mandibular (supra-mandibular) branch, passing downward and forward under cover of the risorius and the depressors of the lower hp, commimicates with the buccal branches and with the ramus colli of the facial nerve, and with the mental branch of the mandibular nerve. It supplies the quadratus labii inferioris and mentalis.
The ramus colli (infra-mandibular branch) runs downward and forward under cover of the platysma, which muscle it innervates (fig. 740). Beneath the platysma it forms one or more communicating loops, near its commencement, with the great auricular nerve, and longer loops, lower down, with the superficial cervical nerve.
Central connections. — The nucleus of origin of the facial in the rhombencephalon includes an anterior and a posterior group of cells which give rise respectively to its upper and lower terminal divisions. They are associated with the somaesthetic area (lower third of the anterior central gyrus) by way of the pyramidal fasciculi of the opposite and same sides, and with the nuclei of the other cranial nerves, including the nucleus of termination of the glosso-palatine, by way of the reticular formation and the medial longitudinal fasciculus.
The glosso-palatine nerve (sensory root or pars intermedia of facial, nerve of Wrisberg) contains both sen.sory and motor fibres. While it has a separate attachment to the medulla, it courses in close company with the facial and, in the internal auditory meatus, it is involved in the same sheath with the facial, which relation is maintained by its larger part thence through the facial canal till a short distance above the stylo-mastoid foramen. Here this larger part leaves the trunk of the facial as the chorda tympani nerve. The origin, central connections and peripheral distribution of the glosso-palatine are similar to those of the
of that nerve.
The sensory portion is much greater than the motor. Its fibres arise from cells situated in the geniculate ganglion which thus corresponds to a spinal ganglion. The central processes from these cells pass medialward in the facial canal (aqueduct of Fallopius) enclosed in the sheath of the facial nerve, which they leave in passing through the internal auditory meatus, to turn slightly downward in the posterior fossa of the cranium and enter the medulla at the inferior border of the pons, between the attachments of the facial and vestibular nerves. They com-se through the reticular formation of the medulla, medianward and dorsalward to terminate about cells which comprise a superior extension of the nucleus of termination of the glosso-pharyngeal nerve (nucleus of ala cmerea). The peripheral processes from the geniculate ganglion are distributed chiefly to the epithelium covering the soft palate, portions of the glosso-palatine arches, and the anterior two thirds of the tongue.
The geniculate ganglion is so named from the fact that it is embedded upon the anterior border of the external genu {geniculum, great bend) of the facial nerve, behind the hiatus Fallopii. It is somewhat triangular in form. From its superomedial angle leave the central processes of its cells, the root of the nerve; from its infero-lateral angle leave the fibres which later leave the sheath of the facial as the chorda tympani, and its anterior angle is connected with the great superficial petrosal nerve (figs. 738 and 741). The geniculate ganglion contains a relatively large number of cell-bodies of sympathetic neurones many of whose processes run in this latter nerve, a relation mentioned below with the gangliated cephalic plexus.
The motor portion of the glosso-palatine consists for the most part of visceral efferent fibres, chiefly secretory. These arise in the medulla oblongata from a small group of cells scattered in the reticular formation dorso-medial to the nucleus of the facial and in line with the dorsal efferent nucleus of the vagus below. It is called the salivaiory nucleus. The fibres course ventralward and lateralward to their exit, mingle with the entering sensory fibres of the glossopalatine in the sheath of the facial and, through the branches of the glossopalatine, pass to terminate in sympathetic ganglia of the head, large and small. These gangfia send axones which terminate in the smooth muscle of vessels and about the cells of the glands of the lingual and palatine mucous membrane and of the salivary glands proper. Some of the motor fibres of the nerve terminate in contact with the sympathetic cells remaining in the geniculate ganglion and which give rise to sympathetic fibres issuing from it. Most of the motor fibres pass into the great superficial petrosal nerve and the chorda tympani to terminate in (chiefly) or pass through the spheno-palatine and submaxillary ganglia respectivelJ^ Some may pass by the geniculo-tympanic branch and tympanic plexus to end in the otic ganghon. Many no doubt end in the smafler ganglia involved in the various sympathetic plexuses. It is suggested that the motor part carries secretory impulses destined chiefly for the sub-maxillary and sublingual glands. A small gangliated plexus on the capsule of the medial side of the parotid gland has been frequently dissected and found to communicate freely with twigs from the facial nerve and twigs concerned with the trigeminus. It is possible that some glosso-palatine visceral motor fibres terminate in these ganglia for secretory impulses to the parotid gland as well.
Central connections. — The nucleus of termination of tlie glosso-palatine nerve (superior extension of the nucleus of termination of the sensory portion of the glosso-pharyngeal) is associated with the somffisthetic area of the cerebral cortex of the opposite and same sides by way of the medial lemniscus, and with the saUvatory nucleus and motor nuclei of other cranial nerves by way of the reticular formation and medial longitudinal fasciculus. The nucleus of origin of the motor portion (sahvatory nucleus) may be associated not only with the nucleus of termination of the sensory part, but with the nuclei of termination of other cranial nerves, and perhaps with the motor area of the cortex of the opposite side by way of the pjTamidal fascicuh.
Branches and communications. — Aside from its two or three small collateral twigs of communication, the fibres of the glosso-palatine course in two main branches or nerves: (1) the great superficial petrosal nerve, continued through the Vidian nerve, and extended through and beyond the spheno-palatine ganglion as the palatine portion of the glosso-palatine (palatine nerve) ; (2) the chorda tym-
to the lingual nerve, a branch of the trigeminus.
In the internal auditory meatus, the glosso-palatine gives two delicate collaterals to the vestibular nerve, and some filaments (visceral motor probably) are described as given to the auditory artery and to the temporal bone.
A large part of the great superficial petrosal nerve is formed of glosso-palatine fibres. This nerve is further described below in its relation to the spheno-palatine ganglion. It arises from the anterior angle of the geniculate ganglion, enters the middle fossa of the cranium through
Fig. 741. — Diagram of the Glosso-palatine Nekve (Black) and the Relations op the Gangliated Cephalic Plexus to otheb Cbanial Nebves. (After Bean.) Broken Mnes, motor; continuous hues, S3'mpathetic; glosso-palatine in solid black. Medial view. Left side.
the hiatus FaUopii, and passes beneath the semilunar ganglion into the foramen lacerum, where it joins with the great deep petrosal nerve to form the Vidian nerve. Thence the glossopalatine portion passes over or through the spheno-palatine ganglion to form the greater part of the small and middle palatine nerves which are distributed to the epithelium and glands of the soft palate, some of the sensory fibres probably terminating in the taste organs found there; the remainder serving as fibres of general sensibility. It is probable that most of the motor glosso-palatine fibres in the great superficial petrosal nerve terminate in the spheno-palatine ganglion; some may pass to the carotid plexus and to smaU gangUa elsewhere.
The chorda tympani consists to a very large extent of sensory fibres (peripheral processes of the cells of the geniculate ganglion), but it also contains motor fibres and is thus also a mixed nerve. It leaves the trunk of the facial nerve a short distance above the stylo-mastoid foramen, and pursues a slightly recurrent course upward and forward in the canaliculus chorda tympani (iter chordae posterius), a minute canal in the posterior wall of the tympanic cavity, and it
enters that cavity close to the posterior border of the membrana tympani. It crosses the cavity, running on the medial surface of the tympanic membrane at the junction of its upper and middle thirds, covered by the mucous membrane lining the tympanic cavity, and passes to the medial Bide of the manubi-ium of the malleus above the tendon of the tensor tympani. It leaves the tympanic cavity and passes to the base of the skull through a smaU foramen (the iter chordae anterius) at the medial end of the petro-tympanic (Glaserian) fissure. At the base of the skull it inclines downward and forward on the medial side of the spine of the sphenoid, which it frequently grooves, and, on the medial side of the pterygoideus externus, it joins the posterior border of the hngual nerve at an acute angle. Some of its fibres (motor chiefly) leave the lingual nerve and pass to the sub-maxillary ganglion, and others (sensory) continue forward to the tongue, where, in company with fibres of the lingual nerve, they terminate in the epithehum covering the anterior two-thirds of the tongue. Some probably serve to convey sensations of taste, most of them are fibres of general sensibility. Before it joins the lingual nerve the chorda tympani receives a communicating twig from the otic ganglion (figs. 738, 741).
a. 3omm. lateral.
the vestibule, and their central processes conveying impulses which are distributed to the gray substance of the cerebellum and spinal cord, the nerve comprises a most important part of the apparatus for the equilibration of the body. It has been customary to describe the vestibular [radix vestibularis] and the cochlear [radix cochlearis] nerves combined as the acoustic (auditory) or eighth cranial nerve. While the two are blended in a common sheath from near the medulla to the bottom of the internal auditory meatus, they are likewise partty enclosed in the same sheath with the facial and glosso-palatine nerves and the internal auditory artery which accompany them in this meatus. At the bottom of the meatus
the vestibular and the cochlear are separate; they are separate at their entrance into the lateral aspect of the medulla oblongata; and their central connections, peripheral distributions and functions are different.
The vestibular nerve arises as processes of the cells of the vestibular ganglion (ganglion of Scarpa), situated upon and blended within the nerve at the bottom of the internal auditory meatus. Unlike the ordinary spinal ganglion, to which it corresponds, the cells of the vestibular ganglion retain an embryonal, "bipolar," form. The central processes course v/ith the cochlear nerve in the internal auditory meatus medialward, caudad and slightly downward, inferior to the accompanying' if acial and glosso-palatine nerves, and, arching ventrally around the restiform body, they enter the medulla at the inferior border of the pons, lateral to the glosso-palatine and facial and medial to the entrance of the cochlear nerve. They find their nucleus of termination spread in the floor of the fourth ventricle and grouped as the median, the lateral (Deiters'), the superior, and the nucleus of the spinal root of the vestibular nei've. In the internal auditory meatus, the vestibular nerve is connected by two small filaments of fibres with the glosso-palatine nerve. These are either visceral motor fibres for the vessels of the domain of the vestibular or are aberrant fibres which course only temporarily with the vestibular and return to the glosso-palatine.
The peripheral processes of the cells of the vestibular ganglion terminate in the specialised or neuro-epithelium comprising the maculm in the sacculus and the utriculus and the cristce in the ampullte of the three semicircular canals. Thus there are five terminal branches of the nerve. None of its fibres terminates in the cochlea. The vestibular ganglion has a lobar form, one lobe giving rise to a superior utriculo-ampuUar division which divides into three terminal branches; the other giving a sacculo-ampuUar division which gives two terminals.
in the macula acustica of the sacculus.
The central connections of the vestibular nerve are described in detail on pages 823, 824. Its large nucleus of termination, spread through the area acustica in the floor of the fourth ventricle, and divided into four sub-nuclei, is associated with the nuclei fastigii, globosus, and emboliformis of the cerebellum, with the nuclei of the eye-moving nerves, with the spinal cord, and probably with the cerebral corte.x.
THE COCHLEAR OR AUDITORY NERVE
The fibres of the cochlear nerve are distributed to the organ of Corti in the cochlea, and so are considered as comprising the auditory nerve proper. They arise from the long, coiled spiral ganglion of the cochlea, the cells of which, like those of the vestibular ganglion, are bipolar. The peripheral processes of these cehs are shorter than those of the vestibular ganglion. They terminate about the auditory or hair-ceUs of the organ of Corti and thus collect impulses aroused by stimuli affecting these cells. The central processes of the ganglion cells continue through the modiolar canal and the tractus spiralis foraminosus of the cochlea, and thence, joining the vestibular nerve through the internal auditory meatus, accompanying the facial nerve and internal auditory artery, they course medialward and downward, approach and enclasp the restiform body (fig. 665) and enter the lateral aspect of brain-stem to terminate in their dorsal and ventral nuclei. A description of these nuclei and the further central connections of the cochlea with the superior olive, the nuclei of the eye-moving nerves, the inferior quadrigeminate bodies, the medial geniculate bodies, and with the cerebellum and temporal lobes of the cerebral hemispheres is given on pages 824, 839.
The glosso-pharyngeal or ninth cranial nerves are mixed nerves and each is attached to the medulla by several roots which enter the posterolateral sulcus, dorsal to the anterior end of the olivary body and in direct line with the facial nerve.
The filaments, when traced lateralward, are seen to blend, in front of the flocculus, into a trunlc which hes in front of the vagus nerve, but which passes through a separate opening through the arachnoid and the dura mater and through the jugular foramen. In the foramen this trunk hes in front, and lateral to the vagus nerve in a groove on the petrous portion of the temporal bone; and in this situation two ganglia are interposed in it, a superior or jugular, and an inferior or petrosal. After it emerges from the jugular foramen the glosso-pharyngeal nerve descends at first between the internal carotid artery and the internal jugular vein and to the lateral side of the vagus; then, bending forward and medialward, it descends medial to the styloid process and the muscles arising from it, and turning around the lower border of the stylo-pharyngeus it passes between the internal and the external carotid arteries, crosses the superficial surface of the stylo-pharyngeus, and runs forward and upward medial to the hyoglossus muscle and across the middle constrictor and the stylo-hyoid ligament, to the base of the tongue (fig. 743).
Ganglia. — The superior or jugular ganglion (ganglion of Ehrenritter), is a small, ovoid, reddish-grey body which lies on the back part of the nerve-trunk in the upper part of the jugular foramen. No branches arise from it. It is sometimes continuous with the petrosal ganglion or it may be absent.
(4) A short distance below the petrous gangUon the trunk of the nerve is connected by a twig with that branch of the facial nerve which supplies the posterior belly of the digastric muscle. There is also a small twig (probalily sensdryl to the stylo-hyoid.
(5) From the petrosal ganglion : The tympanic branch (nerve of Jacobson) arises from the petrosal ganglion and passes through a foramen, which lies in the ridge of bone between the carotid canal and the jugular fossa, into the tympanic canahculus (Jacobson's canal), where it is surrounded by a small, fusiform mass of vascular tissue, the iniumesceniia tympanica. After traversing the tympanic canaliculus it enters the tympanum at the junction of its lower and medial walls, and, ascending on the medial wall, breaks up into a number of branches which take part in the formation of the tympanic plexus on the surface of the promontory (fig. 739). The continuation of the nerve emerges from this plexus as the small superficial petrosal nerve, which runs through a small canal in the petrous portion of the temporal bone, beneath the canal for the tensor tympani, and appears in the middle fossa of the cranium through a foramen which lies in front of the hiatus Fallopii. From this foramen it runs forward and passes through the foramen ovale, the canaliculus innominatus, or the spheno-petrosal suture, and enters the zygomatic fossa, where it joins the otic ganghon. While it is in tlie canal in the temporal bone the small superficial petrosal nerve is joined by a geniculo-tympanic branch from the geniculate gangUon of the glosso-palatine nerve.
(6) Branches from the tympanic plexus : — (a) The tubal branch (ramus tubae), a dehcate branch, which runs forward to the mucous membrane of the tuba auditiva (Eustachian tube) and sends filaments backward to the region of the fenestra vestibuli (ovahs) and the fenestra cochleaj (rotunda).
plexuses of the head and they will be again mentioned below with the gangUated cephalic plexus.
Branches from the trunk of the nerve : — (1) Pharyngeal branches, which may be two or three in number, arise from the nerve a short distance below the petrosal ganglion. The principal and most constant of these passes on the lateral side of the internal carotid artery, and after a very short independent course joins with the pharyngeal branch of the vagus and with branches of the superior cervical ganglion to form the pharyngeal plexus (fig. 743).
(3) The tonsillar branches are a number of small twigs which arise under cover of the hyoglossus muscle; they proceed to the tonsil, around which they form a plexus, the circulus tonsillaris. From this plexus fine twigs proceed to the glosso-palatine arches (pillars of the fauces) and to the soft palate.
(4) The lingual branches are the terminal branches of the nerve and supply the mucous membrane of the posterior half of the dorsum of the tongue, where, chiefly as taste-fibres, they are distributed to the vallate papillae. Some small twigs pass backward to the follicular glands of the tongue, and to the anterior surface of the epiglottis. Other twigs are distributed around the foramen officum, where they communicate with the corresponding twigs of the opposite side.
The sensory fibres. — The sensory fibres of the glosso-pharyngeal nerve spring from the superior and petrosal ganglia and pass peripherally and centrally. The peripheral processes of the ganglion cells are those which are distributed to the mucous membrane (taste-buds) of the tongue and pharynx, and the central processes pass medialward to the medulla. In the medulla they pass dorsalward and medianward through the reticular formation and, bifurcating into ascending and descending branches, they end in the nucleus of termination of the glosso-pharyngeal nerve, that is, in the superior part of the nucleus alae cinereae and in the nucleus of the tractus solitarius.
The motor fibres arise from the nucleus ambiguus in the lateral funiculus of the medulla, in fine with the nucleus of origin of the facial nerve. From this nucleus they pass at first dorsalward and then, turning lateralward, they emerge and join the sensory fibres and run with them in the trunk of the nerve (fig. 646).
Van Gehuchten's observations point to the conclusion that one motor nucleus of the glossopharyngeal nerve is separate from and Kes above and to the medial side of the nucleus ambiguus, and that a portion of the nucleus of the ala cinerea is also a motor nucleus common to the glosso-pharyngeal and vagus nerves. It is quite probable that the former motor nucleus is that now considered as the dorsal motor nucleus of the vagus. An unknown proportion of the motor fibres are visceral motor and course in the various communications of the glossophar3mgeal nerve with cephalic plexus.
Central connections. — The nuclei of termination of the glosso-pharyngeal nerve are associated with the motor nuclei of other cranial nerves by the medial longitudinal fasciculus, and with the somaesthetic area of the cortex cerebri of the opposite side by the medial lemniscus (fillet). The motor nucleus of the nerve is associated with the somaesthetic area by the pyramidal fibres.
The hypoglossal nerves are exclusively motor; they supply the genio-hyoidei and the extrinsic and intrinsic muscles of the tongue except the glosso-palatini. They are usually designated as the twelfth pair of cranial nerves. The fibres of each nerve issue from the cells of an elongated nucleus which lies in the floor of the central canal in the lower half of the medulla and in the floor of the fourth ventricle in the upper half beneath the trigonum hypoglossi. This nucleus is the upward continuation of the ventro-medial group of cells of the ventral horn of the spinal cord. From their origin the fibres run ventralward and somewhat lateralward, probably joined in the medulla by a few fibres from the nucleus ambiguus which is a segment of the upward prolongation of the lateral group of cells of the ventral horn. The conjoined fibres issue from the medulla in the sulcus between the pyramid and the olivary body, in a series of from ten to sixteen root filaments, which pierce the pia mater and unite with each other to form two bundles (fig. 731). These bundles pass forward and lateralward to the hypoglossal (anterior condyloid) foramen, where they pierce the arachnoid and dura mater. In the outer part of the foramen the two bundles unite to form the trunk of the nerve. At its commencement, at the base of the skull, the trunk of the hypoglossus lies on the medial side of the vagus, but as it descends in the neck it turns gradually around the dorsal and the lateral side of the latter nerve, lying between it and the internal jugular vein, and a little above the level of the hyoid bone it bends forward, and crosses lateral to the internal carotid artery, the root of origin of the occipital artery, the external carotid, and the loop formed by the first part of the lingual artery (fig. 743). After crossing the lingual artery it proceeds forward on the lateral svnface of the hyo-glossus, crossing to the medial side of the posterior belly of the digastric, and the stylo-hyoid muscles. It disappears in the anterior part of the submaxillary region between the mylo-hyoid and the hyo-glossus, and divides into its terminal branches between the latter muscle and the genio-glossus.
As it descends in the neck the trunk lies deeply between the internal jugular vein and the internal carotid artery under cover of the parotid gland, the styloid muscles, and the posterior beUy of the digastric, and it is crossed superficially by the posterior auricular and the occipital arteries. As it turns forward around the root of the occipital artery the sterno-mastoid branch of that vessel hooks downward across the nerve, and as it turns forward on the hyo-
glossus muscle it lies immediately above the ranine vein. It is crossed by the posterior belly of the digastric and the stylo-hyoid muscle, and it is covered superficially, behind the mylohyoid, by the lower part of the submaxillary gland.
Communications. — The hypoglossus is connected with the first cervical ganglion of the sympathetic, with the ganglion nodosum of the vagus, with the loop between the first and second cervical nerves, and with the lingual nerve; the latter communication is established along the anterior border of the hyo-glossus muscle (figs. 743 and 744).
(1) A meningeal branch, frequently represented by two filaments, is given off in the hypoglossal (anterior condyloid) canal. It passes backward into the posterior fossa of the cranium and is distributed to the dura mater. It was believed at one time that the fibres of the meningeal branch were derived from the lingual nerve, but it is now deemed more probable that they are either sensory or visceral motor fibres from the cervical nerves, or from the vagus.
(2) Branches which consist of fibres derived from the cervical plexus. — The descendens cervicalis (hypoglossi) and the muscular twig to the thyi'eo-hyoid muscle, though apparently arising from the hypoglossal nerve, consists entirely of fibres which have passed into the hypoglossal nerve from the loop between the first two cervical nerves. Therefore, neither of them are branches of the hypoglossus proper. (See fig. 752.)
(a) The descendens cervicalis (hypoglossi) parts company with the hypoglossus at the point where the latter hooks around the occipital artery (fig. 743). It runs downward and slightly medialward on the sheath of the great vessels (occasionally within the sheath), and is joined at a variable level by branches from the second and third cervical nerves, forming with them a loop, the cervical loop [ansa hypoglossi] (fig. 743). The cervical loop rnay be placed at any level from a point immediately below the occipital artery to about four centinietres above the sternum. From this loop aU the muscles attached to the hyoid bone are supphed. A twig to the anterior belly of the omo-hyoid arises from the descendens cervicalis in the upper part of its course. The nerves which supply the sterno-hyoid, sterno-thyreoid, and posterior belly of the omohyoid are given off by the cervical loop. Twigs from the first two nerves pass downward in the muscles behind the manubrium sterni and •in rare cases communicate with the phrenic
the cervical fascia below the central tendon of the muscle.
(b) The nerve to the thyreo-hyoid leaves the hypoglossus near the tip of the great cornu of the hyoid bone, and runs obhquely downward and medialward to reach the muscle. AU the fibres in (a) and (b) are derived from the first, second and third cervical nerves.
(c) The nerve to the genio-hyoid arises under cover of the mylo-hyoid, where loops are formed with the lingual nerve from which loops branches pass into the muscle. It probably contains some true h}fpoglossal fibres.
hypoglossal nerve crosses it.
The nerve to the genio-glossus arises under cover of the mylo-hyoid in common with the terminal branches to the intrinsic muscles of the tongue. It communicates freely with branches of the lingual, forming long loops which lie on the genio-glossus. From these loops twigs pass into the genio-glossus and into the muscular substance of the tongue.
Central connections. — The nucleus of origin of the hypoglossus is associated with the somEesthetic area (operculum) of the cortex cerebri of the opposite side by the pyramidal fibres, and it is connected with the sensory nuclei (nuclei of termination) of other cranial nerves by way of the reticular formation and the medial longitudinal fasciculus.
THE VAGUS OR PNEUMOGASTRIC NERVE
The vagus or pneumogastric nerves are the longest of the cranial nerves, and they are remarkable for their almost vertical course, their asymmetry, and their extensive distribution, for, in addition to supplying the lung and stomach, as the name ' pneumo-gastric ' indicates, each nerve gives branches to the external ear, the pharynx, the larynx, the trachea, the oesophagus, the heart, and the abdominal viscera. They are commonly referred to as the tenth pair of cranial nerves.
Each nerve is attached to the side of the medulla, in the postero-lateral sulcus, dorsal to the olivary body, by from twelve to fifteen root filaments which are in linear series with the filaments of the glosso-pharyngeal nerve. The filaments contain both sensory and motor fibres. They pierce the pia mater, from which they receive sheaths, and, traced outward, they pass into the posterior fossa of the cranium toward the jugular foramen and unite to form the trunk of the nerve, which passes through openings in the arachnoid and the dtira mater which are common to it and to the spinal accessory nerve. In the jugular foramen a small spherical ganglion, the jugular ganglion (ganglion of the root) , is interposed in the trunk which here turns at right angles to its former course and descends through the neck. As it leaves the jugular foramen it is joined by the internal or accessory portion of the spinal accessory nerve, and immediately below this junction it enters a large ovoid ganglion, the ganglio7i nodosum or ganglion of the trimk (fig. 743). As it descends through the neck the nerve passes ventral and somewhat lateral to the superior cervical sympathetic ganglion, and in front of the longus capitis and longus colh, from which it is separated by the prevertebral fascia. In the upper part of the neck it is placed between the internal carotid artery and the internal jugular vein, and on a plane dorsal to them, the artery being ventral and mesial, and the vein ventral and lateral. In the lower part of the neck it occupies a similar position in regard to the common carotid artery and the internal jugular vein, and the three structures are enclosed in a common sheath derived from the deep cervical fascia, but within the sheath each structure occupies a separate compartment (fig. 743) . In the root of the neck and in the thorax the relations of the nerves of the two sides of the body differ somewhat, and they must, therefore, be considered separately.
The right vagus passes in front of the first part of the right subclavian artery in the root of the neck and then descends in the thorax, passing obliquely downward and backward on the right of the trachea, and behind the right innominate vein and the superior vena cava, to the back of the root of the right lung. Just before it reaches the right bronchus it lies close to the medial side of the vena azygos as the latter hooks forward over the root of the lung. At the back of the right bronchus the right vagus breaks up into a number of branches which join with the branches of tlie sympathetic to form the right posterior pulmonary plexus, and from this plexus it issues in'the form of one or more cords, combined .sensory, visceral motor and sympathetic, which descend on the cesophagus and break up into branches which join with branches of the left vagus, forming the posterior oesophageal plexus. At the lower part of the thorax fibres of this plexus become again associated in one trunk which passes througli the diaphragm on the posterior
The left vagus descends through the root of the neck between the carotid and subclavian arteries and in front of the thoracic duct. In the upper part of the superior mediastinum it ia crossed in front by the left phrenic nerve, and in the lower part of the same region it crosses in
Coeliac plexus
front of the root of the subclavian artery and the arch of the aorta and behind the left superior intercostal vein. Below the aortic arch it passes behind the left bronchus and divides into branches which unite with twigs of the sj'mpathetic to form the left posterior pulmonary plexus. Prom this plexus the fibres of the left vagus issue as one or more cords that break up into anastomosing branches to form the anterior oesophageal plexus. At the lower part of the thorax this plexus becomes a single trunk, which passes through the diaphragm on the anterior surface of the oesophagus, and it is distributed to_the anterior surface of the stomach and tothe liver.
The jugular ganglion (ganglion of the root) is a spherical grey mass about five miUimetres in diameter which lies in the jugular foramen (fig. 744). It is connected with the spinal accessory nerve and with the superior cervical sympathetic ganglion, and it gives off an auricular branch, by means of which it becomes associated with the facial and glosso-pharyngeal nerves, and a recurrent meningeal branch.
The ganglion nodosum (ganglion of the trunk) lies below the base of the skull and in front of the upper part of the internal jugular vein. It is of flattened ovoid form and about seventeen miUimetres long and four millimetres broad (figs. 744 and 743). It is joined by the accessory part of the spinal accessory nerve, and is associated with the hypoglossal nerve, with the superior cervical ganglion of the sympathetic, and with the loop between the first two cervical nerves, and it gives off a pharyngeal, a superior laryngeal, and a superior cardiac branch. Both ganglia and especially the nodosal retain numerous cell-bodies of sympathetic neurones and the twigs issuing from the ganglia thus contain sympathetic fibres. The greater part of the cell-bodies are of sensory neurones.
Communications. — The vagus nerve is connected with the glosso-pharyngeal, spinal accessory and hypoglossal nerves, with the sympathetic, and with the loop between the first and second cervical nerves.
(1) Two communications exist between the vagus and glosso-pharyngeal nerves: one between their trunlis, just below the base of the skull, and one, in the region of their gangha, consisting of one or two filaments. When two filaments are present one passes from the jugular gangUon and the other from the auricular nerve to the petrosal ganghon of the glosso-pharyngeal nerve. Either or both of these filaments may be absent.
(2) Two twigs pass from the spinal accessory nerve to the ganglion nodosum, and at a lower level the accessory part of the spinal accessory nerve also joins the same gangUon (fig. 744). The majority of the fibres of the accessory part of the spinal accessory nerve merely pass across the surface of the ganglion and are continued into the pharyngeal and superior laryngeal branches of the vagus, but a certain number blend with the trunk of the vagus and are continued into its recurrent laryngeal and cardiac branches.
Terminal branches. — These are the meningeal, auricular, pharyngeal, superior laryngeal, recurrent (inferior laryngeal), cardiac, bronchial, pericardial, oesophageal, and the abdominal branches.
(1) The meningeal or recurrent branch is a slender filament which is given off from the jugular ganglion. It takes a recurrent course through the jugular foramen, and is distributed to the dura mater around the transverse (lateral) sinus.
(2) The auricular branch, or nerve of Arnold, arises from the jugular gangUon in the jugular foramen. It receives a branch from the petrosal gangUon of the glosso-pharyngeal, enters the petrous part of the temporal bone through a foramen in the lateral wall of the jugular fossa, and communicates with the facial nerve or merely Ues in contact with it as far as the stylomastoid foramen. It usually leaves the temporal bone by the stylo-mastoid foramen, but it may pass through the tympano-mastoid fissure, and it divides, behind the pinna, into two branches, one of which joins the posterior auricular branch of the facial while the other suppUes sensory fibres to the posterior and inferior part of the external auditory meatus and the back of the pinna. It also suppUes twigs to the osseous part of the external auditory meatus and to the lower part of the outer surface of the tympanic membrane.
(3) The pharyngeal branches may be two or three in number. The principal of these joins the pharyngeal branch of the glosso-pharyngeal on the lateral surface of the internal carotid artery, and after passing with the latter medial to the external carotid artery it turns downward and medialward to reach the posterior aspect of the pharynx. Here the two nerves are joined by branches from the superior cervical ganglion of the sympathetic, with which they form the pharyngeal plexus (figs. 743, 744). Branches from this plexus supply sensory fibres to the mucous membrane of the pharynx and motor fibres to the constrictores pharyngis, levator palatini, uvulae, glosso-palatinus, and pharyngo-palatinus.
(4) The superior laryngeal nerve arises from the lower part of the ganghon nodosum, and passes obliquely downward and medialward behind and medial to both internal and external carotid arteries toward the larynx. In this course it describes a curve with the convexity downward and lateralward and divides into (i) a larger internal and (ii) a smaller external branch (fig. 744). Before its division it is joined by twigs with the sympathetic and with the pharyngeal plexus, and it gives a small branch to the internal carotid artery.
THE VAGUS NERVE 957
(a) The internal branch accompanies the superior laryngeal artery to the interval between the upper border of the thyreoid cartilage and the great cornu of the hyoid bone. It passes under cover of the thyreo-hyoid muscle and pierces the hyo-thyreoid membrane to gain the interior of the pharynx, where it hes in the lateral wall of the sinus piriformis and divides into a number of diverging branches. The ascending branches supply the mucous membrane on both surfaces of the epiglottis, and probably that of a small part of the root of the tongue. The descending branches ramify in the mucous membrane lining the larjmx, and supply the mucous membrane which covers the back of the cricoid cartilage. One of the descending branches passes downward on the internal muscles of the larynx to anastomose with the terminal part of the inferior (recurrent) laryngeal nerve.
(b) The external branch runs downward on the inferior constrictor to the lower border of the th}Teoid cartilage, where it ends, for the most part, in the crico-thyreoid muscle. A few filaments pierce the crico-thyreoid membrane and are distributed to the membrane lining the larynx. It occasionally gives off a cardiac branch which joins one of the cardiac branches of the sympathetic; it also furnishes twigs to the inferior constrictor, and communicating twigs to the pharyngeal plexus, and it receives a communication from the superior cervical gangUon of the sympathetic.
(5) The recurrent (inferior or recurrent laryngeal) nerve of the right side arises from the vagus at the root of the neck in front of the right subclavian artery. It hooks around the artery, passing below and then behind that vessel, and runs upward and slightly medialward, crossing obliquely behind the common carotid artery (fig. 744). Having gained the side of the trachea, it runs upward in the groove between the trachea and the CBsophagus, accompanying branches of the inferior thja-eoid artery, and, near the level of the lower border of the cricoid cartilage, becomes the inferior laryngeal nerve.
In its course the right recurrent nerve gives off branches to the trachea, cesophageal branches to the ojsophagus and pharynx, and, near its commencement, one or more inferior cardiac branches. It communicates with the inferior cervical sympathetic ganghon and with the superior laryngeal nerve.
The inferior laryngeal nerve, the continuation of the recurrent, ascends between the trachea and oesophagus, enters the larynx under cover of the inferior constrictor of the pharynx, and divides into two branches, anterior and posterior. The anterior branch passes upward and forward on the crico-arytajnoideus lateralis and thyreo-arytajnoideus, and supplies these muscles and also the vocalis, arytsenoideus obliquus, ary-epiglotticus, and thyreo-epiglotticus. The posterior branch, passing upward, supplies the crico-arytaenoideus posterior and arytsenoideus obliquus, and anastomoses with the medial branch of the superior laryngeal nerve.
On the left side the recurrent nerve arises in front of the aortic arch and winds around the concavity of the arch lateral to the ligamentum arteriosum. It crosses obliquely behind the root of the left common carotid artery, gains the angular interval between the oesophagus and trachea, and corresponds with the nerve of the right side in the remainder of its course and distribution (fig. 744).
(6) Cardiac branches. — Of these branches of the vagus, there are two sets, the superior and inferior. All the branches of both sets pass to the deep part of the cardiac plexus except a superior branch on the left side that passes to the superficial part of the cardiac plexus. All contain visceral motor, sympathetic and sensory fibres.
(a) The superior (superior and inferior cervical) cardiac nerves arise from the vagus and its branches in the neck (figs. 744, 786). Some of these branches on both sides join with the cardiac branches of the sympathetic in the neck and pass with them to the cardiac plexus. Some on the right side pass independently through the thorax to the deep part of the cardiac plexus, and a branch on the left side passes through the thorax to the superficial part of the cardiac plexus.
(b) The inferior (thoracic) cardiac branches. — These branches on the right side arise in part from the recurrent nerve and in part from the main trunk of the vagus, while on the left side they usually arise entirely from the recurrent. AU these branches pass to the deep part of the cardiac plexus (figs. 744, 786).
(a) The anterior bronchial (pulmonary) branches consist of a few small branches which arise at the upper border of the root of the lung. They pass forward to gain the anterior aspect of the bronchus, where they communicate with the sympathetic and form the anterior pulmonary plexus, from which fine twigs pass along the bronchus.
(b) The posterior bronchial (pulmonary) branches. — Almost the entire remaining trunk of the vagus usuallj' divides into these branches, which join with branches from the second, third, and fourth thoracic ganglia of the sympathetic to form the posterior pulmonary plexus (fig. 744). The plexuses of the two sides join freely behind the bifurcation of the trachea, and branches from the plexus pass along each bronchus into the lung.
and from the oesophageal plexuses lower down, pass to the wall of the oesophagus.
(10) Abdominal branches. — The terminal part of the left vagus divides into many branches, some of which communicate freely along the lesser curvature of the stomach with filaments from the gastric plexus of the sympathetic, and to some extent with branches of the right vagus, to form the elongated anterior gastric plexus (fig. 744). From this plexus as well as from the nerve-trunk, gastric branches are given to the anterior surface of the stomach. Hepatic branches from the trunk or from this plexus pass in the lesser omentum to the hepatic plexus (fig. 744). The terminal part of the right vagus divides into many branches, and forms along the lesser curvature of the stomach an elongated posterior gastric plexus by communications with branches from the gastric plexus of the sympathetic and with branches from the right vagus. Gastric branches are given off by the trunk of the nerve and from this plexus. Coeliac branches are given by the trunk to the cceliac (solar) plexus, and splenic and renal branches, either directly or through the coeliac (solar) plexus, are given to the splenic and renal plexuses (fig. 744) .
Central connections. — The sensory fibres of the vagus are processes of the cells of the jugular ganglion and the ganglion nodosum. The peripheral fibres from these cells bring in sensory impulses from the periphery, and their central fibres convey the impulses to the brain. The latter fibres enter the medulla in the filaments of attachment in the postero-lateral sulcus, and, in the reticular formation, they bifurcate into ascending and descending branches which end in the nuclei of termination of the vagus, namely, in the nucleus alae cinerese in the floor of the fourth ventricle and in the nucleus tractus solitarii. The tractus solitarius consists largely of the descending branches. These and the axones arising from the nuclei of termination of the vagus descend the spinal cord to terminate about ventral horn cells which give origin to the phrenic nerve and to motor fibres supplying other muscles of respiration, and they also convey impulses which are distributed to visceral motor neurones along the spinal cord.
The motor fibres spring from the nucleus ambiguus and from the dorsal efferent (motor) nucleus of the vagus, described on page 820. They join the sensory fibres in the reticular formation. Some of the motor fibres, especially those from the dorsal efferent nucleus, are visceral motor fibres.
The central connections of the vagus are similar to those of the glosso-pharyngeal nerve (fig. 647). Van Gehuchten's observations point to the conclusion that the chief nucleus of termination of the vagus nerve is that of the tractus solitarius.
two parts, the accessory or superior, and the spinal or inferior part.
The fibres of the accessory or superior portion [ramus internus] ("accessory vagus") spring chiefly from the inferior continuation of the nucleus ambiguus, in common with the motor fibres of the vagus above, and they pass through the reticular formation to the postero-lateral sulcus of the medulla, where they emerge as a series of filaments, below those of the vagus. The filaments pierce the pia mater and unite, as they pass outward in the posterior fossa of the cranium, to form a part of the nerve which enters the apertm-e in the dura mater common to the vagus and spinal accessory nerves. In the aperture this trunk is joined by the spinal portion of the nerve.
The spinal or inferior portion [ramus externus] arises from the ventro-lateral cells of the ventral horn of the cord as low as the fifth, and rarely the seventh, cervical nerve. The fibres pass dorsalward and lateralward from their origins through the lateral part of the ventral horn and through the lateral funiculus of white substance, and they emerge from the lateral aspect of the cord behind the ligamentum denticulatum, along an oblique line, the lower fibres passing out immediately dorsal to the ligament, and the upper close to and sometimes in association with the dorsal roots of the upper two spinal nerves. As the spinal fibres pass out of the surface of the cord they unite to form an ascending strand which enters the posterior fossa of the cranium, through the foramen magnum, and, turning lateralward, blends more or less intimately with the accessory portion. Thus combined, the nerve enters the jugular foramen in company with the vagus, but here it is again separated into its two branches, which contain chiefly the same fibres as the original superior and inferior parts.
The superior branch, or accessory portion of the nerve, gives one or more filaments to the jugular ganghon (ganglion of the root of the vagus), and then joins either the trunk of the vagus directly or its ganglion nodosum, the fibres of the branch being contributed to the pharyngeal, laryngeal, and cardiac branches of the vagus. Fibres corresponding to the white rami communicantes, absent in the cervical nerves, probably enter the cervical sympathetic ganglion through this ramus of the spinal accessory nerve. The fibres from the accessory to the vagus therefore probably include visceral motor and cardio-inhibitory fibres.
The inferior branch or the spinal portion runs backward and downward under cover of the posterior belly of the digastric and the sterno-mastoid. It usually crosses in front of and to the lateral side of the internal jugular vein and between it and the occipital artery; then it
GANGLIATED CEPHALIC PLEXUS 959
pierces the slerno-mastoid, supplies filaments to it, and interlaces in its substance with branches of the Second cervical nerve. It emerges from the posterior border of the sterno-mastoid slightly above the level of the upper border of the thyreoid cartilage, passes obliquely downward and backward across the occipital portion of the posterior triangle, and disappears beneath the trapezius about the junction of the middle and lower thirds of the anterior border of that muscle (fig. 743). In the posterior triangle it receives communications from the third and fourth cervical nerves, and beneath the trapezius its fibres form a plexus with other branches of the same nerves. Its terminal filaments are distributed to the trapezius and they can be traced almost to the lower extremity of that muscle.
Central connections. — The nuclei of origin, like other motor nuclei, are connected with the somsesthetic area of the cerebral cortex of the opposite side by the pyramidal fibres, and they are associated with the sensory nuclei of other cranial nerves by the medial longitudinal fasciculus, and with sensations brought in by the spinal nerves by the fibres of the fasciculi proprii.
The sympathetic system of the head, like that of the remainder of the body described below, is arranged in the form of a continuous gangHated plexus subdivided into sub-plexuses. Unlike the great unpaired prevertebral plexuses in the thoracic and abdominal cavities, all the larger sympathetic ganglia of the head are paired, gangha corresponding to each other being found on either side. Thus they may be considered as an upward extension of the series of paired lumbar, thoracic and cervical ganglia belonging to the sympathetic trunks lying along either side of the vertebral column. Numerous small ganglia, many of them microscopic, occur in the sub-plexuses throughout the head. These are irregular in size and position and those in the region of the median line are no doubt unpaired.
In origin, the ganglia of the cephalic plexus consist of cell-bodies which, in the early stages of development, migrated from the fundaments of the ganglia of the vagus, glosso-phar3mgeal and glosso-palatine nerves, and most especially from that of the semilunar (Gasserian) ganglion of the trigeminus — a developmental relation identical with that of the remainder of the sympathetic system to the ganglia of the spinal nerves. Just as is known for the spina! ganglia, some cell-bodies destined to develop into sympathetic neurones, instead of migrating, remained within the confines of the ganglia of the above nerves, in company with the cell-bodies of their sensory neurones. This is thought to be especially true for the geniculate, the petrosal and the jugular ganglion. Therefore these ganglia must be considered as in small part sympathetic ganglia.
The gangliated cephalic plexus could properly be included as a division of the general sympathetic system described later. However, because its larger ganglia are so intimately associated with branches of the oculomotor, trigeminal, masticator, glosso-palatine, glosso-pharyngeal and vagus nerves, it is customary to describe it in connexion with the cranial nerves.
The larger ganglia, one on either side of the head, comprise the ciliary ganglion, the spheno-palatine (Meckel's) ganghon, the otic and the submaxillary ganglion. To these must be added portions of the geniculate, petrosal, jugular and the ganghon nodosum, and a part of the superior cervical sympathetic ganglion. The chief relations of the gangliated cephalic plexus to the cranial nerves are shown in fig. 741.
The so-called roots and branches of the ganglia carry three varieties of fibres: (1) Sensory, (2) Motor (visceral motor or preganglionic), and (3) Sympathetic. Most roots and branches are mixed, the name of a root being determined only by the variety of fibres predominating in it.
A bundle of sensory fibres going to a ganghon is called its sensory root. Such, however, cannot comprise a true root since none of its fibres arises in the ganghon and very few or none may terminate in it. The only sensory fibres terminating in a ganghon are the few which may approach it in any of the roots to terminate in its capsule or the capsules of its cells and convey impulses of general sensibility from the ganghon to the central nervous system. Almost all of the fibres of a "sensory root" merely pass around or through a ganglion and into its branches beyond, which they borrow as paths for reaching their allotted fields of distribution. In this relation it should be realized that while the cihary, spheno-palatine, otic and submaxillary ganglia are customarily described under the discussion of the trigeminus, this nerve has functionally less to do with them than any of the other cranial nerves with which they are associated. Bundles of trigeminal (sensory) fibres, traceable in gross anatomy because meduUated and of appreciable size, pass to the gangha, but only to pass through them as continuations of the terminal branches of the trigeminus.
and branches of a cranial nerve (oculomotor, masticator, etc.) to enter and terminate in contact with the ceU-bodies of the ganglion, which, in their turn, give fibres to the branches of the ganglion; (b) fibres of the same origin, name and course but which may pass thi-ough the ganglion to terminate in contact with the cells of a more distant ganglion. Any root, the motor especially, may contain somatic motor fibres, that is, fibres of central origin which pass through the ganglion uninterrupted and into its branches to terminate upon the fibres of skeletal (voluntary) muscle.
A sympathetic root likewise may carry two and perhaps three varieties of fibres conforming to the name: (a) fibres arising from the cells of other sympathetic gangha and terminating in the ganghon in question; (b) fibres arising in other ganglia which pass through the gangfion in question to enter its branches and terminate either in other ganglia or upon their allotted muscular or glandular elements. A third is the fibre of the sensory sympathetic neurone, probably quite rare, which may arise from a cell-body in the ganglion and pass centralward in its root and in the appropi'iate cranial nerve to terminate about a cell-body of the dorsal-root or spinal ganghon type, the central process of which latter conveys this sensory impulse of sympathetic origin into the central system just as sensory oranio-spinal impulses are conveyed.
Branches of distribution
The branches of distribution of the gangha, the larger of them often called nerves, are those bundles in which the fibres, both arising in or passing through the gangha, course toward their terminations upon their allotted tissue elements of the head. The larger gangha of the head are described as each possessing the three roots above mentioned. In the branches pass fibres motor to the vessels of the head, to the intrinsic muscles of the eye bulb, to the [lacrimal glands, the mucous membranes (gland cells) of the nasal and oral cavities and the salivary glands, and sensory fibres conveying impulses from these structures.
The plexuses into which the gangliated cephalic plexus is divided and which connect the ganglia to form it, are numerous and vary greatly in size. They underlie the mucous membranes and they surround all the vessels and glands. They are named according to their locahty. The largest of them are the tympanic plexus and the carotid and cavernous plexuses. They have been repeatedly referred to in their relations to the branches of the cranial nerves.
Of the numerous branches described from the superior cervical sympathetic ganglion, the two large ones which pass upward associate it especially with the gangliated cephalic plexus. That branch known as the internal carotid nerve may be considered as the direct continuation upward of the gangUated sympathetic trunk of the body. Through the branches of this, the carotico-tympanic and the deep petrosal nerves, and through the plexuses derived from it, the superior cervical ganghon may be associated with practically all the other sympathetic gangha of the head (figs. 7.39 and 741). The other branch from the superior cervical ganghon, the jugular nerve, associates it with the ganglia of the glosso-pharyngeal and vagus nerves, with the petrosa ganghon by a direct branch and with the gangha of the vagus through the nodosal plexus. These latter gangha (and the nerves to which they belong) are connected, chiefly by
The tympanic plexus serves as a common point of distribution of fibres from the superior cervical sympathetic ganglion, the gangha of the vagus, the petrosal ganghon, and the geniculate ganglion, to the cavernous and carotid plexuses and to the spheno-palatine and otic gangha. The superior cervical ganglion is associated with the cavernous and carotid plexuses direct by the internal carotid nerve and with the tympanic plexus by the Inferior and superior caroticotympanic nerves. The tympanic plexus receives fibres from the geniculate ganghon by a small geniculo-tympanic branch and it is connected with the spheno-palatine ganghon by a small anastomotic or tympano-petrosal branch to the great superficial petrosal nerve, and with the otic ganglion by the small superficial petrosal nerve. It is not directly connected with either the cihary or the submaxillary ganglion. However, these ganglia, as well as the sphenopalatine and otic, are connected with the carotid plexus either directly by named branches or indirectly by way of plexuses derived from the carotid. The geniculo-tympanic branch, the tympanic nerve and twigs of the nodosal plexus may be considered as analogous to the rami oommunicantes of^the spinal nerves.
The parotid branches, described above as branches of the auriculo-temporal nerve (from the trigeminus) and as containing fibres from the glossopharyngeal, should be mentioned here as belonging to the gangliated cephalic plexus. These branches are sympathetic fibres arising in the otic ganglion and passing as branches of the ganglion to the auriculo-temporal in which they remain till this nerve enters the parotid gland and then they are distributed to the gland. The visceral motor or preganglionic fibres which terminate about their cells of origin in the otic ganglion are derived from the glosso-pharyngeal nerve and pass successively through the tympanic nerve, the tympanic plexus, and the small superficial petrosal nerve to the otic ganglion.
The tympanic nerve (tympanic branch of the glosso-pharyngeal, or nerve of Jacobson), the branch to the Eustachian tube (ramus tubes), and the superior and inferior carotico-lympanic branches are also described as branches of the glosso-pharyngeal nerve. These must hkewise be considered as belonging to the gangliated cephahc plexus.
For purposes of dissection, it may be more expedient to consider separately, with its roots and branches, each of the larger ganglia of the gangliated cephalic plexus. Under this heading belong in part the geniculate ganglion of the glossopalatine nerve, and the ganglia of the glosso-pharyngeal and vagus, especially the petrosal ganglion of the former and the jugular ganglion of the latter, from the fact that these ganglia contain numerous cell-bodies of sympathetic neurones as well as those of the sensory neurones of their nerves.
sensory and motor roots of their sympathetic portions are contained in the roots of their nerves. The geniculate probably has no sympathetic root. The sympathetic roots of the petrosal and jugular ganglia are contained in the branches of the jugular nerve. The chief branches of distribution of the geniculate are the geniculo-tympanic branch, the great superficial petrosal nerve, and the external superficial petrosal nerve. The branches of the petrosal ganghon are the tympanic nerve and its branches of the tympanic plexus. The chief branch of distribution from the jugular ganglion is contained in the auricular branch of the vagus, or nerve of Arnold, supplemented by sympathetic fibres in the trunk of the vagus itself.
The Ciliary Ganglion
The ciliary, lenticular, or ophthalmic ganglion lies in the posterior part of the orbital cavity, about 6 mm. in front of the superior orbital (sphenoidal) fissure, to the lateral side of the optic nerve, and between the optic nerve and the external rectus muscle. It is a small, reddish, quadrangular body, compressed laterally, and it measures about two millimetres from before backward (fig. 734).
Roots. — (o) Its motor or short root enters its lower and posterior angle and is a visceral motor branch derived from the branch of the inferior division of the oculomotor nerve which supplies the inferior oblique muscle. The fibres of the motor root probably all terminate in the ciliary ganglion in connection with motor sympathetic neurones.
(6) The sensory or long root passes through the upper and back part of the ganglion. It is a branch of the naso-oiliary (nasal) nerve and is, therefore, composed of fibres from the trigeminus passing through the ganglion.
Branches. — From three to six short ciliary nerves emerge from the anterior border of the ganglion ; they divide as they pass forward and eventually form about twenty nerves which are arranged in aii upper and a lower group, and the latter group is joined by the long ciliary branches of the naso-ciliary (nasal) nerve, now sensory and sympathetic (fig. 73-1). When they reach the eyeball, the ciliary nerves pierce the sclerotic around the optic nerve, and pass forward in grooves on the inner surface of the sclera. The sympathetic fibres contained are distributed as motor fibres to the ciliary muscle, the sphincter of the iris, and to the vessels of these and of the cornea.
This ganglion is associated with the maxillary nerve (fig. 743). It is a small reddish-grey body of triangular form, which is flattened at the sides, and measiu-es about five millimetres from before backward. It lies deeply in the pterygopalatine (spheno-maxillary) fossa at the lateral side of the spheno-palatine foramen and in front of the anterior end of the pterygoid (Vidian) canal. It is attached to the maxillary nerve, from which it receives its sensory root, and it is connected with the Vidian nerve, which furnishes it with motor and sympathetic filaments (fig. 739).
The exact position of the ganghon depends upon the size and shape of the sphenoidal air cells. When these are small, or high and narrow, the ganglion lies lateral to them; when they are large, or broad and fiat, the ganglion lies inferior to them. Sometimes it may lie anterior to them if the cells are short from in front backward. The ganglion may be reached with ease by chipping away the bone around the sphenoidal air cells after the skull is divided sagitally.
Roots. — (a) Its motor root, consisting of visceral motor fibres of the glosso-palatine nerve, is contained in the great superficial petrosal nerve which is incorporated in the Vidian nerve. It springs from the anterior angle of the geniculate ganglion and passes through the hiatus of the facial canal (hiatus Fallopii) into the middle fossa of the cranium, where it runs forward and medialward, in a groove on the upper surface of the petrous part of the temporal bone, to the foramen laoerum, and in this part of its course it passes beneath the semilunar (Gasserian) ganghon and the masticator nerve. In the foramen lacerum it joins with the great deep petrosal nerve to form the Vidian nerve (nerve of the pterygoid canal), which passes forward through the pterygoid (Vidian) canal and its motor and sympathetic fibres terminate in the spheno-palatine ganglion in the pterygo-palatine (spheno-maxillary) fossa. The great superficial petrosal nerve contains sensory as well as sympathetic and motor fibres. The sensory fibres pass through the ganghon and, in the small palatine nerve, descend to the soft palate, where they terminate in the epithelium covering it and some are probably concerned with peripheral taste organs found there. They arise from the cells of the geniculate ganglion and therefore belong to the glosso-palatine nerve.
(6) The sympathetic root is the great deep petrosal portion of the Vidian nerve. This root, which is of reddish colour and of soft texture, springs from the carotid plexus which lies on the outer side of the internal carotid artery in the carotid canal. It enters the foramen lacerum through the apex of the petrous portion of the temporal bone, and unites with the great superficial petrosal branch of the facial nerve to form the Vidian nerve. The great superficial petrosal nerve also carries sympathetic fibres to the spheno-palatine ganglion, derived from the geniculate ganglion and from the tj'mpanic plexus.
The Vidian nerve [n. canalis pterygoidei] commences by the union of the great superficial and deep petrosal nerves in the foramen lacerum, and runs forward through the pterygoid (Vidian) canal to the pterygo-palatine (spheno-maxillary) fossa to the spheno-palatine ganglion. The Vidian nerve often may be seen in a ridge of bone along the floor of the sphenoidal cells and its direction there depends upon the position of the spheno-palatine ganglion. While it is in the pterygoid canal the Vidian nerve is joined by a sphenoidal filament from the otic ganghon, and it gives branches to the upper and back part of the roof and septum of the nose, and to the lower end of the Eustachian tube.
(c) The sensory roots consist of the sensory fibres mentioned above in the great superficial petrosal nerve and of usually two spheno-palatine branches from the maxillary nerve. The majority of the fibres of these roots do not join the ganghon, but pass by its medial side and enter the palatine branches.
Ascending branches. — The orbital or ascending branches are two or three small twigs which enter the orbit through the inferior orbital (spheno-maxillary) fissure and proceed, within the periosteum, to the inner wall of the orbit, where they pass through the posterior ethmoidal foramen and through the foramina in the suture behind that foramen to be distributed to the mucous membrane which lines the posterior ethmoidal cells and the sphenoidal sinus.
Internal branches. — The internal or nasal branches are derived in part from the medial side of the ganglion, but are also largely made up of fibres which pass from the spheno-palatine branches of the maxillary nerve without traversing the ganglionic substance. They are disposed in two sets, the lateral and the medial (septal) posterior superior nasal branches.
The lateral posterior superior nasal branches are six or seven small twigs which pass through the spheno-palatine foramen, and are distributed to the mucous membrane covering the posterior parts of the superior and middle nasal conchae (turbinated bones) (fig. 732). They also furnish twigs to the lining membrane of the posterior etlimoidal cells.
The medial posterior superior nasal (septal) branches, two or three in number, pass medialward through the spheno-palatine foramen. They cross the roof of the nasal fossa to reach the back part of the nasal septum, where the smaller twigs terminate. The largest nerve of the set, the naso-palatine nerve, or nerve of Cotunnius, runs downward and forward in a groove in the vomer between the periosteum and the mucous membrane to the incisive (anterior palatine) canal, where it communicates with the nasal branch of the anterior superior alveolar nerve. The two naso-palatine nerves then pass through the foramina of Scarpa in the intermaxillary suture, the left nerve passing through the anterior of the two foramina. In the lower part of the incisive (anterior palatine) canal the two nerves form a plexiform communication (for-
anterior palatine nerves.
Descending branches. — The descending branches are the great or anterior, the posterior, and the middle (external) palatine nerves. Like the internal set of branches, they are in part derived from the ganglion and in part are directly continuous with the spheno-palatine nerves (fig. 732).
The great or anterior palatine nerve, its sensory fibres derived from the maxillary nerve, arises from the inferior angle of Meckel's ganglion, and passes downward through the pterygopalatine canal, accompanied by the descending palatine artery. Emerging from the canal at the greater (posterior) palatine foramen it divides into two or three branches, which pass forward in gi-ooves in the hard palate and supply the glands and mucous membrane of the hard palate and the gums on the inner aspect of the alveolar border of the upper jaw. During its cour.se through the pterygo-palatine canal the anterior palatine nerve gives off the posterior inferior nasal nerves. These nerves pass through small openings in the perpendicular plate of the palate bone to supply the mucous membrane covering the posterior part of the inferior nasal concha (turbinated bone) and the adjacent portions of the middle and inferior meatuses of the nose.
The posterior or small palatine nerve passes downward through a lesser palatine foramen (accessory palatine canal), and enters the soft palate, distributing branches to that organ, to the uvula, and to the tonsil. Its sensory fibres are derived from the glosso-palatine nerve, through the great superficial petrosal nerve and through the spheno-palatine ganglion. It was formerly believed to convey motor fibres from the facial nerve to the levator palati and azygos uvulae, but it is now beheved that these muscles are supplied by the spinal accessory nerve through the pharyngeal plexus (fig. 732).
The middle (external) palatine nerve, the smallest of the three, in part, likewise from the glosso-palatine nerve, traverses a lesser palatine foramen and supplies twigs to the tonsil and to the adjacent part of the soft palate (fig. 732).
Posterior branch. — The pharyngeal branch, which is of small size, passes backward and somewhat medialward through the pharyngeal canal accompanied by a pharj'ngeal branch of the spheno-palatine artery. It is distributed to the mucous membrane of the uppermost part of the pharynx, to the upper part of the posterior nares, to the opening of the Eustachian tube, and to the lining of the sphenoidal sinus. Its sensory fibres are derived from the maxillary nerve.
The otic or Arnold's ganglion is a small reddish-grey body which is associated with the mandibular nerve. It lies deeply in the zygomatic fossa, immediately below the foramen ovale, on the inner side of the trunk of the mandibular nerve. It is in relation internally with the tensor palati, which separates it from the Eustachian tube. It is compressed laterally, and its greatest diameter, which lies antero-posteriorly, is about three millimetres.
Roots. — The ganglion is closely connected with the nerve to the pterygoideus internus, through which it may receive a motor root from the masticator nerve. Through the small superficial petrosal nerve, which joins the upper and back part of the ganglion, it receives a motor root from the glosso-palatine nerve and sensory and motor fibres from the glossopharyngeal nerve. It receives also a slender sphenoidal filament from the Vidian nerve. The sympathetic roots are derived from the small superficial petrosal nerve and from the sympathetic plexus on the middle meningeal artery.
Branches. — The communicating branches which pass from the ganglion are: — (1) The filaments to the chorda tympani; some of whose fibres probably terminate in the submaxillary ganglion; (2) filaments to the auriculo-temporal nerve; (3) filaments to the spinous nerve (the recurrent branch of the mandibular nerve). The branches of distribution are sympathetic to the vessels and somatic motor branches to the tensor tympani, and tensor veli palatini.
The submaxillary ganglion is suspended from the lingual division of the mandibular nerve by anterior and posterior branches. It is a small reddish body, of triangular or fusiform shape, which lies between the mylo-hyoideus and hyoglossus and above the duct of the submaxillary gland.
Roots. — The sensory root is received from the lingual nerve. The motor root is from both the masticator nerve by way of the lingual nerve, and from the glosso-palatine nerve by way of the chorda tympani. The motor fibres pass from the chorda tympani after it has joined the lingual, and the sensory fibres come directly from the lingual nerve. The sympathetic root is formed by filaments from the sympathetic plexus on the facial artery.
The spinal nerves are arranged in pairs, the nerves of each pair being symmetrical in their attachment to either side of their respective segment of the spinal cord, and, in general, symmetrical in their course and distribution. There are usually thirty-one pairs of functional spinal nerves. For purposes of description these are topographically separated into eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar, five pairs of sacral, and one pair of coccygeal nerves. Occasionally the coccygeal or thirty-first pair is practically wanting, while, on the other hand, there may be frequently found small filaments representing one or even two additional pairs of coccygeal nerves below the thirty-first pair. These rudimentary coccygeal nerves are probably not functional. They never pass outside the vertebral canal, and often even remain within the tubular portion of the filum terminale. There sometimes occurs an increase in the number of vertebrae in the vertebral column and in such cases there is always a corresponding increase in the number of the spinal nerves.
Origin and attachment. — Each spinal nerve (unlike the cranial nerves) is attached to the spinal cord by two roots: — a sensory or afferent dorsal root [radix posterior] and a motor or efferent ventral root [radix anterior]. Each dorsal root has interposed in its course an ovoid mass of nerve-cells, the spinal ganglion, and the nerve-fibres forming the root arise from the cells of this ganglion and are thus of peripheral origin. The fibres composing the ventral root, on the other hand, are of central origin; they arise from the large motor cells of the ventral horn of the grey column within the spinal cord.
Each dorsal root-fibre upon leaving its cell of origin pursues a short tortuous course within the spinal ganglion and ^hen undergoes a T-shaped bifurcation, one product of which passes toward the periphery, where it terminates for the collection of sensations and is known as the peripheral branch, or, since it conveys impulses toward the cell-body, the dendrite of the spinal
ganglion neurone. It is more correct, however, to consider the T-fibre as a bifurcated axone. The other product of the bifurcation, the central branch, passes into the spinal cord and in its course toward the cord contributes to form the dorsal root proper.
The central branches, upon emerging from the spinal ganglia, form a single compact bundle at first, which passes through the dura mater of the spinal cord and then breaks up into a series, of root-filaments [fila radicularia]. These thread-like bundles of fibres spread out vertically in a fan-like manner and enter the cord in a direct linear series along its postero-lateral sulcus. The fibres of the ventral root emerge from the cord in a series of more finely divided root filaments, which, unlike the entering filaments of the dorsal root, are not arranged in direct linear series, but make their exit over a strip of the ventro-lateral aspect of the cord in some places as much as two millimetres wide.
As they enter the spinal cord the fibres of the dorsal roots undergo a Y-shaped division, both products of which course in the cord longitudinally, an ascending and a descending branch. The descending or caudal branches are shorter than the ascending, and soon enter and terminate
about the cells within the grey column of the cord, forming either associational, commissural, or reflex connections, or about cells whose fibres form cerebellar connections. The ascending or cephalic branches are either short, intermediate, or long. The short and intermediate branches are similar in function to the descending branches, save that they become associated with the grey substance of segments of the cord above rather than below the level of their entrance. The long branches convey impulses destined for the structures of the brain, and pass upward in the fasciculus gracilis or fasciculus cuneatus of the cord, and terminate in the nuclei of these fasciculi in the meduUa oblongata (figs. 618 and 620).
Aberrant spinal ganglia. — In serial sections on either side of the spinal ganglion of a nerve there may often be found outlying cells either scattered or in groups of sufficient size to be called small gangUa. Such are more often found in the dorsal roots of the lumbar and sacral nerves. These cells are nothing more than spinal ganghon-cells displaced in the growth processes, and have the same nature and function as those in the ganghon. In some animals occasional cells very rarely have been found in the outer portion of the ventral root. These probably represent afferent fibres which enter the cord by way of the ventral root. Likewise, especially in the birds and amphibia, it has been shown that occasional efferent fibres may pass from the grey substance of the cord to the periphery by way of the dorsal instead of the ventral root.
Relative size of the roots. — The sensory or dorsal root is larger than the ventral root, indicating that the sensory area to be supplied is greater and perhaps more abundantly innervated than the area requiring motor fibres.
It has been shown that in the entire thirty-one spinal nerves of one side of the body of man the dorsal root-fibres number 653,627, while all the corresponding ventral roots contain but 233,700 fibres, a ratio of 3.2 : 1. (Ingbert.) In the increase in the size of the nerves for the supply of the limbs the gain of dorsal root or sensory fibres is far greater than the gain of ventral root-fibres. The first cervical or the sub-occipital nerve is always an exception to the rule; its dorsal root is always smaller than its ventral, and in rare cases may be rudimentary or entirely absent. The spinal ganghon and, therefore, the sensory root of the coccygeal nerve, is also quite frequently absent.
The dorsal and ventral root-fibres of each spinal nerve proceed outward from their segment of attachment to the spinal cord, pierce the pia mater and arachnoid, collect to form their respective roots, and pass into their respective intervertebral foramina. On the immediate peripheral side of the spinal ganglion the two roots blend, giving origin to the thus mixed nerve-trunk. As the trunk, the sensory and motor fibres make their exit from the vertebral canal through the intervertebral foramen.
Relation to the meninges. — The root filaments of each nerve receive connective-tissue support from the pia mater and arachnoid in passing through them. In the sub-arachnoid cavity they become assembled into their respective nerve-roots; and the roots, closely approaching each other, pass into the dura mater, from which they receive separate sheaths at first, but at the peripheral side of the ganglion these sheaths blend into one, which, with the subsequent blending of the roots, becomes the sheath or epineurium of the nerve trunk. By means of the sheaths derived from the meninges, especially the dura, the nerve-roots and the trunk are attached to the periosteum of the margins of the intervertebral foramina and thus are enabled to give some lateral support to the spinal cord in the upper portion of the canal.
The majority of the spinal ganglia lie in the intervertebral foramina, closely ensheathed, and thus outside the actual sac or cavity of the dura mater. The gangha of the last lumbar and first four sacral nerves he inside the vertebral canal, but since the sheath derived from the dura mater closely adheres to them, they are still outside the sac of the dura mater. The gangha of the last sacral and of the coccygeal nerves (when present) lie in tubular extensions of the sub-dural cavity, and thus not only within the vertebral canal, but actually within the sac of the dura mater. The trunk of the first cervical nerve is assembled within the sac of the dura mater, and, therefore, the spinal ganghon of this nerve, when present, may he within the sac.
Course and direction of emergence. — Invested with the connective-tissue sheath derived from the meninges, each thoracic, lumbar and sacral nerve emerges from the vertebral canal through the intervertebral foramen below the corresponding vertebra, and all the nerves are in relation with the spinal rami of the arteries and veins associated with the blood supply of the given localities of the spinal cord.
The first cervical nerve does not pass outward in an intervertebral foramen proper, but between the occipital bone and the posterior arch of the atlas and beneath the vertebral artery. Thus the eighth or last cervical nerve emerges between the seventh cervical and the first thoracic vertebra.
The first and second pairs of cervical nerves pass out of the vertebral canal almost at right angles to the levels of their attachment to the spinal cord. During the early periods of development the level of exit of each pair of spinal nerves is opposite the level of its attachment to the
cord, but, owing to the fact that in the later periods the vertebral column grows more rapidly than the cord and increases considerably in length after the cord has practically ceased growing, all the spinal nerves, with the exception of the first two, pass downward as well as outward. The obhquity of their course from the level of attachment to the level of exit increases progressively from above downward, and, as the cord ends at the level of the first or second lumbar vertebra, the roots of the lower lumbar and of the sacral nerves pass at first vertically downward within the dura mater, and form aroimd the filum terminale a tapering sheaf of nerve-roots, the Cauda equina (horse's tail) (fig. 613, p. 773).
Topography of attachment. — The relations between the levels of attachment of the spinal nerves to the cord and the spinous processes of the vertebrae situated opposite these levels have been investigated by Nuhn and by Reid. The following table compiled by Reid gives the extreme limits of attachment as observed in six subjects.
(A) signifies the highest level at which the root filaments of a given nerve are attached to the cord, and (B) the lowest level observed. For example, the root filaments of the sixth thoracic nerve may be attached as high as the lower border of the spinous process of the second thoracic vertebra, or some may be attached as low as the upper border of the spinous process of the fifth thoracic vertebra, but in a given subject they do not necessarily extend either as high or as low as either of the levels indicated.
(B) Junction of upper two-thirds and lower third of interval between seventh cervical and first thoracic vertebra. Second " (A) Lower border of spine of sixth cervical vertebra.
(B) Just above lower border of spine of fifth thoracic vertebra. Eighth " (A) Junction of upper two-thirds and lower third of interval between spines of fourth thoracic and fifth thoracic vertebra.
Relative size of the nerves. — The size of the different spinal nerves varies greatly. Just as the spinal cord shows marked enlargements in the cervical and lumbar regions necessitated by the greater amount of innervation required of these regions for the structures of the upper and lower limbs, so the nerves attached to these regions are considerably larger than elsewhere.
The smaller nerves are found at the two extremities of the cord and in the mid-thoracic region. The smallest nerve is the coccygeal, and the next in order of size are the lower sacral and the first two or three cervical nerves. The largest nerves are those which contribute most to the great nerve trunks for the innervation of the skin and muscles of the limbs: — the lower cervical and first thoracic for the upper limbs and the lower lumbar and first sacral for the lower Umbs. The nerves gradually increase in the series in passing from the smaller toward the larger.
The primary divisions of the nerve-trunk. — A typical spinal nerve (middle thoracic, for example), just as it emerges from the intervertebral foramen, divides into four branches: — the two large primary divisions; viz., the posterior primary division [ramus posterior] and the anterior primary division [ramus anterior]; third, the small ramus communicans, by which it is connected with the sympathetic; and fourth, the smaller, ramus meningeus {recurrent branch), which immediately turns centralward for the innervation of the membranes and vessels of the spinal cord.
In general, the posterior primary division passes dorsalward between the arches or transverse processes of the two adjacent vertebrae in relation with the anterior costo-transverse ligament, and then divides (with the exception of the first cervical, the fourth and fifth thoracic, and the coccygeal nerves) into a medial (internal) branch and a lateral (external) branch. The medial branch turns toward the spinous processes of the vertebrse, and supplies the bones and joints and the muscles about them, and may or may not supply the skin overlying them. The lateral branch turns dorsalward and also supplies the adjacent muscles and bones, and, if the medial branch has not supplied the overlying skin, it also terminates in cutaneous twigs.
In the upper half of the spinal nerves the medial branches supply the skin; in the lower half, it is the lateral branches which do so. Both branches of almost aU the posterior divisions, especially those of the lower nerves, show a tendency to run caudalward and thus are distributed to muscles and skin below the levels of their respective intervertebral foramina. They never supply the muscles of the limbs, though their cutaneous distribution extends upon the buttock, the shoulder, and the skin of the back of the head as far upward as the vertex. The posterior primary divisions, with the exception of those of the first three cervical nerves, are much smaller than the anterior primary divisions.
As their mixed function suggests, the posterior primary divisions contain both nerve-fibres from the ventral roots and peripheral processes of the spinal ganghon-cells. If the nerve-trunk on the immediate peripheral side of the spinal ganghon be teased, bimdles of ventral root-fibres may be seen crossing the trunk obliquely to enter the posterior division, and fibres from the spinal ganghon may be also traced into it. Also a few sympathetic fibres, derived chiefly by way of the ramus communicans, are known to course in it for distribution in the walls of the blood-vessels, etc., of the area it suppUes.
The anterior primary divisions run lateralward and ventralward. With the exception of the first two cervical nerves, which contribute the hypoglossal loop, they are larger than the posterior primary divisions, and appear as direct continuations of the nerve-trunks. Only in case of most of the thoracic nerves do thej^ remain independent in their course. In these they run lateralward and ventralward in the body-wall. In general, these divisions supply the lateral and ventral
Sympathetic ganglion \ Gangliated Sympathetic trunk j trunk Sympathetic cell body in spinal ganglion
Branch to prevertebral ganglion
parts of the body, the limbs, and the perineum. In the cervical, lumbar, and sacral regions they lose their anatomical identity by dividing, subdividing, and anastomosing with each other so as to give rise to the three great spinal plexuses of the body — the cervical, the brachial, and the lumbo-sacral plexuses. The majority of the thoracic nerves retain the typical or primitive character in both their anterior and posterior primary divisions. In them the anterior division (intercostal nerve) divides into a lateral or dorsal and an anterior or ventral branch, both of which subdivide. The lateral branch is chiefly cutaneous; it pierces the superficial muscles and, in the subcutaneous connective tissue, divides into a smaller posterior and a larger anterior ramus, which respectively supply the skin of the sides and the lateral part of the ventral surface of the body. The anterior branch continues ventralward iii the body-wall, giving off twigs along its course to the adjacent muscles and bones, and, as it approaches the ventral mid-fine of the body, it turns sharply lateralward and sends rami medialward and lateralward to supply the skin of the ventral aspect of the bodjr. In the region of the limbs the typical arrangement is interfered with in that what corresponds to the lateral and anterior branches of the division are carried out into the limbs for the skin and muscles there, instead of supplying the lateral and ventral parts of the body-wall.
RAMI COMMUNICANTES
Nerve-fibres arising in the spinal ganglion and fibres from the ventral root pass directly from the nerve-trunk into the anterior primary division of the spinal nerve. This division also receives sympathetic nerve-fibres by way of the ramus communicans. These latter accompany the division and are distributed to their allotted elements in the territory it supplies.
Fig. 749. — Table Giving the Approximate Areas of Distribution of the Different Spinal Nerves with a Diagram showing Their Respective Levels of Exit from the Vertebral Column. (Arranged by Dr. Gowers.)
Plantar
The rami communicantes are small, short, thread-like branches by which the nerve-trunks are connected with the nearest ganglion of the vertically running gangliated cord of the sympathetic (sympathetic trunk). The trunk or anterior primary division of every spinal nerve has at least one of these; most of the nerves have two, and sometimes there are three. The nerves of the cervical region usually have but one, and this is composed largely of sympathetic fibres (grey
In the upper cervical and in the sacral regions one sympathetic ganglion may be connected with two or more spinal nerves, and sometimes one nerve is connected with two ganglia. The rami communicantes of the spinal nerves are equivalent to the communicating rami connecting certain of the cranial nerves with the sympathetic system (trigeminus, glosso-pharyngeus, vagus) . The medullated fibres of the rami and, therefore, the white rami consist chiefly of fibres from the spinal nerves, viz., fibres from the spinal ganglion-cells which enter and course to their distribution through branches of the sympathetic nerves, visceral afferent fibres, and fibres from the ventral roots of the spinal nerves which terminate in the sympathetic ganglia, visceral efferent (preganghonic) fibres. Thus the white rami have been termed the visceral divisions of the spinal nerves. The grey rami consist chiefly of sympathetic fibres, most of which are non-meduUated or partially medullated, and which course to their distribution by way of the spinal nerves. Some of the sympathetic fibres terminate in the spinal ganghon, afferent sympathetic fibres (fig. 748). The usual absence of white rami communicantes from the cervical nerves is explained on the grounds — (1) that probably relatively few efferent visceral fibres are given to the sympathetic from this region of the cord; (2) that many of the visceral efferent fibres which do arise from this region of the cord probably join the rootlets of the spinal accessory nerve and pass to the sympathetic system through the trunk of this nerve, and through the vagus with which it anastomoses; and (3) that such of these fibres as are given off from the lower segments of the cervical region, descend the cord and pass out by way of the upper thoracic nerves which give very evident white rami to the sympathetic.
The meningeal or recurrent branch (figs. 747, 748, and 762) is very small and variable, and is often difficult to find in ordinary dissections. It is given off from the nerve-trunk just before its anterior and posterior primary divisions are formed. It consists of a few peripheral branches of spinal ganglion-cells (sensory fibres) which leave the nerve-trunk and re-enter the vertebral canal for the sensory innervation of the meninges, and which are joined by a twig from the grey ramus or directly from the nearest sympathetic ganglion (vaso-motor fibres). There is considerable evidence, both physiological and anatomical, obtained chiefly from the animals, which shows that at times certain of the peripheral spinal ganghon or sensory fibres may turn backward in the nerve-trunk and pass to the meninges within the ventral root instead of contributing to a recurrent branch. The occurrence of such fibres in the ventral root explains the physiological phenomenon known as 'recurrent sensibility.' Likewise, sympathetic fibres entering the trunk through the grey ramus may pass to the meninges by way of the ventral root, and at times the recurrent branch is probably absent altogether, its place being taken entirely by the meningeal fibres passing in the ventral root.
Areas of distribution of the spinal nerves. — Both the posterior and anterior primary divisions divide and subdivide repeatedly, and their component fibres are distributed to areas of the body more or less constant for the nerves of each pair, but the distribution of the different nerves is very variable. Corresponding to their attachment, each to a given segment of the spinal cord, the nerves have primarily a segmental distribution, but, owing to the developmental changes and displacement of parts during the growth of the body, the segmental distribution becomes greatly obscured and in some nerves practically obliterated. Naturally it is more retained by the nerves supplying the trunk than by those contributing to the innervation of the limbs and head, and the areas supplied by the posterior primary divisions are less disturbed than those supplied by the anterior. The segmental areas of cutaneous distribution of the posterior divisions are more evident than the areas of muscle supplied by these divisions, from the fact that the segmental myotomes from which the dorsal muscles arise fuse together and overlap each other considerably during development. No nerve has a definitely prescribed area of distribution, cutaneous or muscular, for its area is always considerably overlapped by the areas of the nerves adjacent to it. The mid-thoracic nerves more nearly supply a definitely prescribed belt of the body.
A. POSTERIOR PRIMARY DIVISIONS
The posterior primary divisions of the spinal nerves spring from the trunks immediately outside the intervertebral foramina, and they pass dorsalward between the adjacent transverse processes. With the exceptions of the first and second cervical nerves they are smaller than the corresponding anterior primary divisions, which in these nerves is smaller from the fact that a large portion of them go over into the hypoglossal or cervical loop. The posterior primary divisions, after passing between the transverse processes into the region of the back, divide into medial and lateral branches. This division, however, does not occur in the cases of the first cervical, the last two sacral, and the coccygeal nerves.
The posterior primary division of the first cervical or sub -occipital nerve springs from the trunk, between the vertebral artery and the posterior arch of the atlas, passes dorsalward into the sub-occipital triangle, and breaks up into branches which supply the superior oblique, the inferior oblique, and the major rectus capitis posterior muscles, which form the lateral boundaries of the triangle. It also gives a branch across the posterior surface of the major rectus capitis posterior to the minor rectus capitis posterior, and a branch to the semispinalis capitis (complexus) in the roof of the triangle.
It communicates with the medial branch of the posterior primary division of the second cervical nerve, either through or over the inferior obUque muscle, and it occasionally gives a cutaneous branch to the skin of the upper part of the back of the neck and the lower part of the scalp.
The posterior primary division of the second cervical nerve is the largest posterior division of all the cervical nerves. It divides into a small lateral branch and a very large medial branch. The lateral branch gives a twig to the inferior oblique and terminates in branches which supply the splenius and longissimus capitis (trachelo-mastoid) muscles. The medial branch is the greater occipital nerve. It turns around the lower border of the inferior oblique, crosses the sub-occipital triangle obliquely, pierces the semispinalis capitis (complexus), the tendon of the trapezius, and the deep cervical fascia, passing through the latter immediately below the superior nuchal line of the occipital bone, and it divides into several terminal sensory branches which ramify in the superficial fascia of the scalp.
It gives one or two motor twigs to the semispinalis capitis (complexus), and its terminal branches which are accompanied by branches of the occipital artery supply the skin of the scalp, above the superior nuchal Une, as far forward as the vertex. Occasionally one branch reaches the pinna and supplies the skin on the upper part of its medial aspect. As it turns around the inferior oblique it gives branches which join with the medial branches of the posterior primary divisions of the first and third cervical nerves, and in this manner a small looped plexus is formed beneath the semispinalis capitis (complexus) muscle, the posterior cervical plexus of Cruveilhier.
The posterior primary branches of the third, fourth, and fifth cervical nerves
divide at the lateral border of the semispinalis colli into medial and lateral branches. The medial branches of the third, fourth, and fifth nerves run backward between the semispinalis colli and capitis (complexus), supplying both muscles. Then, after passing backward between the semispinalis capitis and the ligamentum nuchse, they pierce the origin of the trapezius and supply the skin of the back of the neck. The greater part of the medial branch of the third nerve, which runs upward in the superficial fascia to the scalp, is called the third or smallest occipital nerve ; it interlaces with the greater occipital nerve, and it supplies the skin of the upper part of the back of the neck, near the middle line, and the skin of the scalp in the region of the external occipital protuberance.
The medial branches of the posterior primary divisions of the sixth, seventh, and eighth cervical nerves pass to the median side of the semispinalis colli, between it and the subjacent multifidus spinse, and they end in the neighbouring muscles. The lateral branches of the posterior primary divisions of the last five cervical nerves are small and they are distributed to the longissimus capitis (trachelomastoid), the ilio-costalis cervicis (cervicalis ascendens), the longissimus cervicis (transversalis cervicis), the semispinalis capitis (complexus), and the splenius muscles.
2. Thohacic Nerves
The posterior primary divisions of all the thoracic nerves divide into medial and lateral branches while in the vertebral groove. The medial branches of the upper six thoracic nerves pass dorsalward between the semispinalis dorsi and the multifidus spinje; they supply the spinalis dorsi, the semispinahs dorsi, the multifidus spinse, the rotatores spinse, the intertransversales, and the interspinales muscles; and they end in cutaneous branches which, after piercing the trapezius, turn lateralward in the superficial fascia of the back, and supply the skin as far as the middle of the scapula. The cutaneous branch of the second nerve is the largest; it can be traced lateralward as far as the acromion process. The medial branches of the lower six thoracic nerves run dorsalward, between the longissi-
simus dorsi and the ilio-costalis dorsi (accessorius) and end in those muscles, but the lateral branches of the six lower nerves are longer; they pass into the interval between the longissimus dorsi and the ilio-costalis dorsi and give branches to them, and then they pierce the latissimus dorsi and are distributed to the skin of the lower and lateral part of the back.
The medial branches of the posterior primary divisions of all the lumbar nerves end in the multifidus spinse and those of the three lower nerves send very small branches to the skin of the sacral region.
The lateral branches of the upper three nerves pass obliquely lateralward, supplying twigs to the adjacent muscles, pierce the posterior layer of the lumbar aponeurosis at the lateral bord^' of the sacro-spinalis (erector spinse) and enter the subcutaneous tissue. They are, for the most part, cutaneous, forming the superior clunial nerves, which cross the crest of the iUum and pass downward to occupy different planes in the thick superficial fascia which covers the upper part of the gluteus medius.
The branch from the first lumbar nerve is comparatively small, and occupies the most superficial plane. The second occupies an intermediate position. The lateral branch from the third nerve is the largest of the three, and occupies the lowest position; it distributes branches over the gluteus maximus as far as the great trochanter. The three nerves anastomose with one another and also with the cutaneous branches from the posterior primary divisions of the two upper sacral nerves.
The lateral branch of the fourth lumbar nerve is of small size and ends in the lower part of the sacro-spinalis (erector spinas). That of the fifth lumbar is distributed to the sacro-spinalis and communicates with the first sacral nerve.
4. Saceal Nerves
The posterior primary divisions of the upper four sacral nerves escape from the vertebral canal by passing through the posterior sacral foramina; those of the fifth sacral nerve pass out through the hiatus sacralis between the posterior sacrococcygeal ligaments. Those of the upper three sacral nerves divide in the ordinary manner into medial and lateral branches. Those of the lower two sacral nerves remain undivided.
The medial branches of the upper three sacral nerves are of small size, and are distributed to the multifidus spinse. The lateral branches anastomose with one another and with the lateral branch of the last lumbar nerve, forming loops on the posterior surface of the sacrum from which branches proceed to the posterior surface of the sacro-tuberous (great sacro-sciatic) ligament, where they anastomose and form a second series of loops, from which loops two or three branches are given off. These branches pierce the gluteus maximus and come to the surface of that muscle in a line between the posterior superior spine of the ilium and the tip of the coccyx. Then, as the middle clunial nerves, they are distributed to the integument over the medial part of the gluteus maximus, and communicate, in their course through the superficial fascia, with the posterior branches of the lumbar nerves.
The posterior divisions of the lower two sacral nerves unite with one another, with the posterior branch of the third sacral, and with the coccygeal nerve, forming loops from which twigs pass to the integument over the lower end of the coccyx.
The posterior primary division of the coccygeal nerve is also undivided. It separates from the anterior division in the sacral canal and emerges through the hiatus sacralis, pierces the hgaments which close the lower part of that canal, receives a communication from the posterior division of the last sacral nerve, and ends in the skin over the dorsal aspect of the coccyx.
The anterior primary divisions of the spinal nerves are larger than the posterior primary divisions, and each is joined near its origin bj^ a grey ramus communicans from the sympathetic gangUated cord (figs. 751, 752, 762). Beginning with the first or second thoracic nerve and ending with the second or third lumber nerve, each anterior division sends to the gangliated cord a white ramus communicans. The same is true of the second and third or of the third and fourth sacral nerves. These white rami are appropriately designated the visceral branches of
the spinal nerves. The anterior primary divisions of the cervical, lumbar, sacral, and coccygeal nerves unite with one another to form plexuses, but the anterior primary divisions of the thoracic nerves, except the first and last, remain separate, pursue independent courses, and each divides, in a typical manner, into a lateral and an anterior or ventral branch. The separation of the anterior primary division into lateral and anterior branches is not confined to the thoracic nerves; it occurs also in the lower cervical, the lumbar, and the sacral nerves, but such a division cannot be clearly distinguished either in the upper cervical nerves, or in the coccygeal nerve.
The anterior primary divisions of the upper four cervical nerves unite to form the cervical plexus, and each receives a communicating branch from the superior cervical sympathetic ganglion. The anterior divisions of the lower four cervical nerves are joined by the greater part of the first thoracic nerve and they unite to form the brachial plexus (figs. 751, 754, 755). The fifth and sixth cervical nerves receive communicating branches from the middle cervical sympathetic ganglion, and the seventh and eighth from the inferior cervical ganglion, while the first thoracic nerve is always connected with the first thoracic sympathetic ganglion by a grey ramus (figs. 751, 786) and in most cases also by a white ramus communicans.
The cervical plexus (figs. 751, 752) is formed by the anterior primary divisions of the upper fom- cervical nerves which constitute the roots of the plexus. It lies in the upper part of the side of the neck, under cover of the sterno-mastoid, and upon the levator scapulse and the scalenus medius. It is a looped plexus, consisting of three loops.
A large part of the anterior primary division of the first cervical nerve is given to the hypoglossal or cervical loop; the remainder passes to the cervical plexus and in doing so it runs lateralward on the posterior arch of the atlas beneath the vertebral artery, then it turns forward, between the vertebral artery and the outer side of the upper articular process of the atlas, and finally it descends, in front of the transverse process of the atlas, and unites with the upper branch of the second nerve, forming with it the first loop of the plexus. It gives branches to the rectus capitis lateralis, longus capitis (major rectus capitis anterior), and to the rectus capitis anterior (minor). The division communicates with the ganglion of the trunk of the vagus and with the superior cervical ganglion of the sympathetic system (fig. 752) . From the first loop of the plexus, two branches of the division pass over into the sheath of the hypoglossal nerve and descend with it to contribute to the hypoglossal loop [ansa hypoglossi] or better, the cervical loop. The fibres entering the sheath of the hypoglossus, after giving a few twigs to the gpnio-hyoid and thyreo-hyoid muscles, leave the sheath as the descendens cervicalis (hypoglossi) and this latter joins the communicans cervicalis, (the portion of the loop from the second and third cervical nerves) and thus completes the cervical or hypoglossal loop.
This loop usually may be found between the sheaths of the sterno-mastoid muscle and the carotid artery, superficial to the internal jugular vein; sometimes it may lie in the carotid sheath between the carotid artery and the internal jugular vein; rarely it may lie dorsal to both the artery and vein. Sometimes it is relatively long, descending toward the sternum below the level of the thyreoid cartilage; again it is quite short and occurs near the level of the hyoid bone. The descendens cervicahs (hypoglossi) parts company with the hypoglossal nerve at the level at which the nerve curves around the occipital artery. It runs downward and shghtly medialward on the sheaths of the great vessels and occasionally within the sheath of one of them.
The second cervical nerve (anterior primary division) passes behind the upper articular process of the axis and the vertebral artery, and between the intertransverse muscles extending from the first to the second cervical vertebrse, to the interval between the scalenus medius and the longus capitis (rectus capitis anterior major), where it divides into two parts. The upper part ascends and unites with the first nerve to form the first loop of the plexus, and the lower branch passes downward and dorsalward and joins the upper branch of the third nerve in
the second loop of the plexus (figs. 751, 752). This branch gives off the small occipital nerve and a filament to the sterno-mastoid, which communicates with the spinal accessory nerve in the substance of the muscle, and it gives branches which assist in forming the hypoglossal or cervical loop (ansa hypoglossi) the cervical cutaneous and the great auricular nerves (fig. 752).
The third and fourth cervical nerves pass behind the vertebral artery (fig. 751) and between the intertransverse muscles to the interval between the scalenus medius and the longus capitis (rectus capitis anterior major), where the third unites with the second and fourth nerves and completes the lower two loops of the plexus. The anterior primary divisions of these nerves are about double the size of the preceding. The third gives off branches to the hypoglossal loop, to the
larger part of the great auricular and cervical cutaneous nerves, a branch to the phrenic, a branch to the supra-clavicular nerves, and muscular branches to the scalenus medius, levator scapulse, longus capitis, and trapezius (fig. 752). The trapezius branch joins the spinal accessory nerve beneath the muscle. The fourth nerve gives a branch to the phrenic, a branch to the supra-clavicular nerves, and muscular branches to the scalenus medius, levator scapulae, longus colli, and trapezius (fig. 752). The branch to the trapezius unites with the one from the third nerve and joins the spinal accessory nerve beneath the muscle.
The fibres forming the cervical (hypoglossal) loop innervate all the muscles of the infra-hyoid group, though twigs to the genio-hyoid and thyreohyoid seemingly enter these muscles from the trunk of the hypoglossus (fig. 752).
supraclavicular supraclavicular
The nerve to genio-hyoid is given off from the trunk under cover of the mylo-hyoid in common with the terminal branches of the hypoglossal proper going to the intrinsic muscles of the tongue. The nerve to the thyreo-hyoid muscles leaves the trunk of the hypoglossal near the tip of the great cornu of the hyoid bone, running obUquely downward and medianward to reach its muscle. A twig to the anterior belly of the omo-hyoid is given from the upper part of the descendens cervicalis and the nerves for the sterno-hyoid, the sterno-thyreoid and the posterior belly of the omo-hyoid are supplied from the turn of the loop (fig. 7.52). The nerves to the sterno-hyoid and sterno-thyreoid send twigs downward in the muscles behind the manubrium sterni and fibres from these in rare cases join the phrenic nerve in the thorax. The nerve to the posterior belly of the omo-hyoid courses as a loop in the cervical fascia below the central tendon of its muscle.
Superficial Branches of the Cervical Plexus
The superficial branches are described, according to the direction in which they run, as ascending, transverse, and descending branches. The ascending branches are the small occipital and the great auricular nerves. There is only one transverse branch, the cervical cutaneous (transverse cervical), and the descending branches are distinguished as the supraclavicular nerves and the cervical (hypoglossal) loop.
upward and^dorsalward to the posterior border of the sterno-mastoid, where it hooks around the lower border of the spinal accessory nerve and then ascends along the posterior border of the muscle to the mastoid process. It pierces the deep cervical fascia and passes across the posterior part of the insertion of the sterno-mastoid into the superficial fascia of the scalp, in which it breaks up into auricular, mastoid, and occipital terminal branches.
(a) The auriculax branch runs upward and slighly forward to reach the integument on the upper median part of the auricle (pinna), wliioh it supphes. (6) The mastoid branch is distributed to the slvin covering the base of the mastoid process, (c) The occipital branches ramify over the occipitaUs muscle and are distributed to the skin of the scalp ' they communicate with one another and with the great occipital nerve. The branches of the small occipital nerve
(2) The great atiricular nerve arises from the second and third cervical nerves (figs. 751, 752). It accompanies the small occipital to the posterior border of the sterno-mastoid, but at that point it diverges from the small occipital (fig. 753) and runs upward and forward across the sterno-mastoid toward the angle of the mandible. When it is about half-way across the muscle it begins to break up into its terminal branches, which are named, according to the area of their distribution, mastoid, auricular, and facial.
As the nerve ascends obliquely across the sterno-mastoid it is embedded in the deep cervical fascia, is covered by superficial fascia and the platysma, and it lies parallel with and slightly dorsal to the external jugular vein, (a) The mastoid branch is small, and is distributed to the integument covering the mastoid process. It anastomoses with the posterior auricular and small occipital nerves. (6) The auricular branches are three or four stout twigs which interlace with the branches of the posterior auricular nerve; they cross the superficial surface of the posterior auricular branch of the facial, and are distributed to the skin on the back of the auricle with the exception of its uppermost part. One or two twigs pass through fissures in the cartilage of the auricle, and are distributed to the integument on the lateral surface of the lobule and the lateral surface of the lower part of the helix and anthelix. (c) The facial branches pass upward and forward among the superficial lobules of the parotid gland, and supply the skin over that gland and immediately in front of it, and they anastomose in the substance of the gland with the cervico-facial division of the facial nerve. In some cases fine twigs may be traced forward nearly to the angle of the mouth.
(transverse cervical) arises from the second and third cervical nerves (figs. 751, 752), and appears at the posterior border of the sterno-mastoid, a little below the great auricular nerve. It passes transversely across the sterno-mastoid under cover of the integument, platysma, and external jugular vein, and divides into a number of twigs which spread out after the manner of a fan, and, as they approach the middle line, extend from the chin to the sternum (fig. 753).
The upper two or three of these twigs unite, beneath the platysma, with the cervical (inframandibular) branch of the facial and thus form loops. From the terminal branches of the nerve numerous twigs arise which pierce the platysma and end in the skin of the front part of the neck.
The descending or supra-clavicular branches. — These are derived from the third and fourth cervical nerves (figs. 751, 752), and arise under cover of the sterno-mastoid. At their commencements they are usually united with the muscular branches destined for the trapezius. They become superficial at the middle of the posterior border of the sterno-mastoid, and as they pass downward they pierce the deep cervical fascia. They include the following:
(1) The anterior supra-clavicular (suprasternal) branches (fig. 753) are small, and cross over the clavicular attachment of the sterno-mastoid to reach the integument over the upper part of the manulDrium sterni. They also supply the sterno-clavicular joint. (2) The middle supra-clavicular (supra-clavicular) nerves are of considerable size. They cross in front of the middle third of the clavicle under cover of the platysma, and are distributed to the skin covering the upper part of the pectoralis major as low as the third rib. (3) The posterior supraclavicular (supra-acromial) branches (fig. 753) cross the clavicular insertion of the trapezius and the acromion process. They are distributed to the skin which covers the upper two-thirds of the deltoid muscle and they supply the acromio-clavicular joint.
The lateral branches of the deep series include communicating branches from the second, third, and fourth cervical nerves to the spinal accessory nerve, and muscular branches to the sterno-mastoid and the scalenus medius, levator scapulse, and trapezius.
3. The nerves to the levator scapulae (fig. 752) are derived from the third and fourth cervical nerves, and occasionally from the second or fifth. They pierce the superficial surface of the levator scapute, and supply the upper three divisions of that muscle.
4. The branches to the trapezius (fig. 752) are usually in the form of two stout twigs which are given off by the third and fourth cervical nerves. They emerge from under cover of the sterno-mastoid at its posterior border and cross the posterior superior triangle of the neck at a lower level than the spinal accessory nerve (fig. 753). They pass under cover of the trapezius in company with the last-named nerve, and communicate with it to form the subtrapezial plexus, from which the trapezius is supplied.
The communicating branches (figs. 751, 752) include (1) branches which connect each of the first four cervical nerves with the superior cervical ganghon of the sympathetic; (2) a branch to the vagus; (3) a branch to the hypoglossal; and (4) branches which pass from the second and third cervical nerves to the descendens cervicalis (hypoglossi) . The ultimate distribution of the twigs connected with the sympathetic and the vagus nerves is not known, but the fibres which pass to the hypoglossal nerve pass from it to the thyreo-hyoideus muscle, and to the descendens cervicalis and the latter joins with the branches from the second and third cervical nerves, forming with them the cervical or hypoglossal loop [ansa hypoglossi] which lies on the carotid sheath. From this loop the two beUies of the omo-hyoid muscle and the sterno-hyoid and sterno-thyreoid muscles are supphed as described above.
The muscular branches supply the rectus capitis lateralis, the longus cap'tis (rectus capitis anterior major), the rectus capitis anterior (minor), the scalenus anterior, and the diaphragm. The nerve to the latter muscle is the phrenic.
and additional branches also from the fifth and sixth nerves.
5. The phrenic nerve (fig. 752) springs chiefly from the fourth cervical nerve, but it usually receives a twig from the third and another from the fifth cervical nerve, a small communicating branch from the sympathetic, and, rarely, a branch from the vagus. The twig from the fifth cervical nerve is frequently connected with the nerve to the subclavius. After the union of its roots the phrenic nerve passes downward and medialward on the scalenus anterior (fig. 755). In this part of its course it is crossed by the tendon of the omo-hyoid and by the transverse cervical and transverse scapular (suprascapular) arteries. It is overlapped by the internal jugular vein, and it is covered by the sterno-mastoid muscle. From the root of the neck the relations of the phrenic nerves differ. The right phrenic nerve descends along the medial surface of the right pleural sac and crosses in front of the root of the lung. It is accompanied by the pericardiaco-phrenic artery (comes nervi phrenici), and it is in relation medially, and from above downward, with the right innominate vein, the superior vena cava, and the pericardium, the latter membrane separating it from the wall of the right atrium (auricle) . The left phrenic nerve descends along the medial surface of the left pleural sac accompanied by the pericardiaco-phrenic (comes nervi phrenici) artery. In the superior mediastinum it lies between the left common carotid and the left subclavian arteries, and it crosses in front of the left vagus, the left superior intercostal vein, and the arch of the aorta. Below the arch of the aorta it crosses in front of the root of the left lung, and then hes along the left lateral surface of the pericardium, which separates it from the wall of the left ventricle.
Branches. — Both phrenic nerves distribute branches to the pericardium and to the pleura. The right nerve gives off a branch, pericardiac, which accompanies the superior vena cava and supplies the pericardium. Each phrenic nerve divides into numerous terminal phrenicoabdominal branches. As a rule, the right phrenic nerve divides into two main terminal branches, an anterior and a posterior. The anterior branch runs forward and one of its terminal filaments
anastomoses with the phrenic of the opposite side in front of the pericardium; others descend between the sternal and costal attachments of the diaphragm into the abdomen, where some of them supply the diaphragm and others descend in the falciform Ugament to the peritoneum on the upper surface of the liver. The posterior branch passes through the vena caval opening and ramifies upon the lower surface of the diaphragm, anastomosing with the diaphragmatic plexus of the sympathetic, and its terminal branches supply the muscular fibi-es of the right half of the diaphragm, the inferior vena cava, and the right suprarenal gland.
The left phrenic nerve divides into several branches. One of the most anterior branches anastomoses with the right phrenic nerve; the others pierce the diaphragm and ramify on its under surface, where they anastomose with filaments of the left diaphragmatic plexus of the sympathetic and supply the left half of the diaphragm and the left suprarenal gland. The left phrenic nerve is considerably longer than the right nerve, partly on account of the lower level of the diaphragm on the left side, and partly on account of the greater convexity of the left side of the pericardium.
divisions of the four lower cervical nerves and the greater part of that of the
Fig. 754. — Diagbam op a Common Form op Bbachial Plexus. The posterior cord of the plexus is darkly shaded. Fifth cervical — ^j\ \( From fourth cervical
and second thoracic nerves.
The anterior primary divisions of the lower four cervical nerves, after passing dorsal to the vertebral artery and between the anterior and posterior parts of the intertransverse muscles, pass into the posterior triangle in the interval between the adjacent borders of the anterior and middle scalene muscles, where the fifth and sixth nerves receive a grey ramus communicans each from the middle cervical sympathetic ganglion, and the seventh and eighth nerves each receive a grey ramus from the inferior cervical sympathetic ganglion. The first thoracic is connected by two rami communicantes with the first thoracic sympathetic ganglion, and it divides into a smaller and a larger branch. The smaller branch passes along the intercostal space as the first intercostal nerve, and the larger branch, after being joined by a twig from the second thoracic nerve, passes upward and lateralward, in front of the neck of the first rib and behind the apex of the pleural sac, into the lower part of the posterior triangle of the neck, where it takes part in the formation of the plexus.
except that the fifth and sixth nerves often unite before branching and give off their posterior branches as a common trunk, and the eighth nerve often receives its branch from the first thoracic nerve before giving off its posterior branch.
It is on account of this variation in the point of union of the fifth and sixth cervical nerves and of the eighth cervical and first thoracic nerves that so many different forms of the plexus have been pictured and described. But if the differences in primary branching be borne in mind, the formation of the plexus is always uniform and simple, notwithstanding its different appearances.
cutaneous
Three cords are formed from these branches in the following manner: — (1) The lateral (outer) cord [fasciculus lateralis] is formed by the anterior branches of the fifth, sbcth, and seventh nerves; (2) the medial (inner) cord [fasciculus medialis], by the anterior branches of the eighth cervical and first thoracic nerves; and (3) the 'posterior cord [fasciculus posterior], by the posterior branches of all of these cervical nerves.
of its three cords divides into two terminal branches, and it lies in the posterior triangle, in the root of the neck, and in the axillary fossa. In the posterior triangle and in the root of the neck it is in relation liehind with the scalenus medius (figs. 751, 755). In the posterior triangle it is covered superficially by the skin and superficial fascia, the pJatysma, the supra-clavicular branches of the cervical plexus, and the deep fascia, and it is crossed by the lower part of the external jugular vein, by the nerve to the subclavius, the transverse cervical vein and the transverse scapular (supra-scapular) vein, the posterior belly of the omo-hyoid muscle, and by the transverse cervical artery. In the axillary fossa the cords are arranged around the axillary artery, the lateral (outer) cord lying lateral to the artery, the medial (inner) cord medial to it, and the posterior cord dorsal to the artery. In this region the posterior relations of the plexus are the fat in the upper part of the fossa and the subscapularis muscle, and it is covered in front by the pectoral muscles and the coraco-clavicular fascia. The lower border of the plexus is in relation in the posterior triangle and at the root of the neck with the pleura and the first rib, and it is overlapped in front by the third part of the subclavian artery. In the axillary fossa the medial cord which forms the lower border of the plexus is overlapped anteriorly by the axillary vein. The upper and lateral border of the plexus has no very important relations.
In gross, the brachial plexus may be formulated as beginning with five nerves and terminating in five nerves, with its intermediate portions displayed in sets of threes. It begins with the fifth, sixth, seventh and eighth cervical and first thoracic nerves; it terminates as a plexus with the formation of the musculocutaneous, radial, axillary, median, and ulnar nerves; in its intermediate portions, first main trunlcs are formed and these divide into two sets of threes which, by union, give rise to three cords. The branches from the cords are three main lateral branches from each and the terminal branches of the plexus. The lateral branches, according as they are given off above, below, and dorsal to the clavicle, are grouped as the supra-clavicular, the infra-clavicular and the subscapular portions of the plexus.
The branches of the supra-clavicular portion. — After the roots of the plexus have received communications from the sympathetic, which have already been referred to, they give off a series of muscular branches, viz. — the posterior thoracic nerves (the dorsal scapular and the long thoracic nerve), the suprascapular nerve, a twig to the phrenic, the nerve to the subclavius, and small twigs to the scalene muscles and the longus colli muscle.
The posterior thoracic nerves are two in number: — (a) the dorsal scapular (nerve to the rhomboids) arises principally from the fifth cervical nerve, but it frequently receives a twig from tihe fourth nerve (fig. 751).
It passes downward and dorsalward, across the middle scalene, parallel with and below the spinal accessory nerve to the anterior border of the levator scapulae, under which it disappears. It continues its descent under cover of the levator scapulae and the rhomboids almost to the lower angle of the scapula, lying a little medial to the posterior border of the bone, and it supplies the lower fibres of the levator and the smaller and larger rhomboid muscles.
It usually arises, by three roots, from the fifth, sixth, and seventh cervical nerves. The last is sometimes absent (figs. 751 and 754). The upper two roots traverse the substance of the scalenus medius; the root from the seventh passes in front of that muscle. Twigs are furnished to the superior portion of the serratus anterior by the upper two roots; lower down they unite and are subsequently joined by the root from the seventh when present. The trunk of the nerve passes downward behind the brachial plexus and the first stage of the axillary artery, and runs along the axihary surface of the serratus anterior (magnus), supplying twigs to each of the digitations of that muscle (fig. 755).
It receives fibres from the fifth and sixth cervical nerves, and occasionally also a twig from the fourth nerve. It is a nerve of considerable size, and it passes downward and dorsalward parallel with the dorsal scapular nerve, at first along the upper border of the posterior belly of the omo-hyoid muscle, then internal to the latter muscle and under cover of the anterior border of the trapezius to the suprascapular notch (fig. 755), where it comes into relation with the transverse scapular (suprascapular) artery. It is separated from the artery at the notch by the superior transverse ligament, the nerve passing through the notch and the artery above the ligament. After entering the supraspinous fossa the nerve supplies branches to the supraspinatus and a branch to the shoulder-joint; then it descends through the great scapular notch between the bone and the inferior transverse ligament to the infraspinous fossa, where it terminates in the infraspinatus muscle.
MEDIAL BRACHIAL CUTANEOUS NERVE
The nerve to the subclavius (fig. 755) is a small twig which arises from the fifth nerve or from the upper trunk of the plexus, but occasionally it receives additional fibres from the fourth and sixth nerves. It runs downward in front of the lower part of the plexus and the third stage of the subclavian artery and, after giving off sometimes a branch to the phrenic, pierces the posterior layer of the coraco-clavicular fascia, and enters the subclavius at its lower border._
three or four cervical nerves immediately after their exit from the intervertebral foramina.
The lateral branches of the infra-clavicular portion of the brachial plexus are the anterior thoracic nerves, from the lateral and medial cords respectively, the medial antibrachial (internal) cutaneous and the medial brachial (lesser internal) cutaneous nerves, from the medial cord, and the subscapular nerves and thoraco-dorsal from the posterior cord.
Supraacromial
It arises from the lateral cord of the plexus and contains fibres from the fifth, sixth, and seventh cervical nerves (figs. 751, 754, 755). After joining the medial anterior thoracic it pierces the coraco-clavicular fascia and ends in branches that supply the pectoraUs major muscle. The medial anterior thoracic nerve arises from the medial cord (figs. 751, 754, 755), contains fibres from the eighth cervical and first thoracic nerves, and passes forward between the first stage of the axillary artery and the axillary vein. It unites with a branch from the lateral anterior thoracic, to form a loop which is placed in front of the first stage of the axillary artery; it gives branches to the pectoralis minor, and branches which pass through the latter muscle and end in the pectorahs major. From the loop additional branches are furnished to the pectoralis major.
The medial brachial (lesser internal) cutaneous nerve, or nerve of Wrisberg (fig. 754), arises from the medial cord of the brachial plexus and sometimes contains fibres from the eighth cervical and first thoracic nerves, but usually fibres
from the first thoracic nerve alone. It runs downward on the medial side of the axillary vein, being separated by that vessel from the ulnar nerve, and it continues downward with a slight inclination dorsalward under cover of the deep fascia on the inner side of the arm. At the middle of the arm it pierces the deep fascia, and near the bend of the elbow it turns somewhat sharply dorsalward to supply the integument which covers the olecranon process (fig. 756).
As it traverses the axilla the nerve of Wrisberg communicates with the intercosto-braohial nerve, forming one, or sometimes two loops (fig. 754). In its course clown the arm it gives a few fine twigs to the integument. This nerve may be absent, its place being taken by the intercosto-braohial or by part of the posterior brachial (.internal) cutaneous branch of the radial (musculo-spu-al) or, rarely, by a branch from the fu'st intercostal nerve.
The medial antibrachial (internal) cutaneous nerve (figs. 751 and 754) arises from the medial cord in close relation with the ulnar nerve. It contains fibres from the eighth cervical and first thoracic nerves. At its origin it lies directly on the medial side of the axillary artery (fig. 755), but it soon becomes more superficial and then lies in the groove between the arterj^ and the vein. In the upper two-thirds of the arm it lies in front and to the medial side of the brachial artery. It divides into two branches (volar and ulnar) which supply the medial aspect of the forearm.
At the junction of the middle and lower thirds of the arm this nerve pierces the deep fascia, in company with the basilic vein, and divides into an anterior and a posterior branch. Previous to its division it gives off twigs which pierce the deep fascia and supply the integument of the upper and medial part of the arm. The volar (anterior) branch is larger than the ulnar (posterior) ; it passes in front of or dorsal to the median basilic vein, and divides into several twigs which run down the forearm, supplying the integument covering its anterior and medial aspect as far as the wrist, and anastomosing with the branches of the ulnar nerve. The ulnar (posterior) branch passes downward and dorsalward in front of the medial condyle of the humerus, and divides into branches which supply the skin on the postero-medial aspect of the forearm. It anastomoses with the dorsal antibrachial (inferior external) cutaneous branch of the radial (musculo-spiral) nerve and the dorsal branch of the ulnar nerve).
The subscapular nerves are branches of the posterior cord (fig. 754). They are three in number, are distinguished as upper, thoraco-dorsal or middle, and lower, and are distributed to the subscapularis, latissimus dorsi, and teres major muscles.
The upper or short subscapular nerve is derived from the fifth and sixth cervical nerves. It hes in the upper and posterior part of the a.xillary fossa, and it is distributed exclusively to the subscapularis muscle. It is occasionally double.
The thoraco-dorsal, middle, or long subscapular nerve consists mainly of fibres from the seventh and eighth cervical nerves, but it may contain fibres from the fifth or the sixth nerve. It passes behind the axillary artery, accompanies the subscapular artery along the axillary margin of the subscapularis muscle, and ends in the latissimus dorsi (fig. 755).
The lower subscapular nerve, carrying fibres from the fifth and sixth cervical nerves, passes behind the subscapular artery, below the circumflex branch (dorsahs scapulae), and is distributed to the teres major, and furnishes to the subscapularis one or two twigs which enter that muscle near its axillary margin.
The terminal branches of the plexus are two from each cord. The posterior cord divides into the axillary (circumflex) and the radial (musculo-spiral) nerves. The lateral cord divides into the musculo-cutaneous nerve, and the lateral root of the median nerve; the medial cord divides into the ulnar nerve, and the medial root of the median nerve, the median nerve as a whole being one of the five terminal branches of the plexus.
The axillary (circumflex) nerve is the smaller of the two terminal branches of the posterior cord, and contains fibres from the fifth and sixth cervical nerves (figs. 751 and 754). At the lower border of the subscapularis it passes dorsalward and accompanies the posterior circumflex artery through the quadrilateral space, which is bounded by the teres major, long head of triceps, and subscapularis muscles, and the surgical neck of the humerus, and it divides into a smaller superior and. a larger inferior division. Previous to its division it furnishes an articular twig to the shoulder-joint. This twig pierces the inferior part of the articular capsule.
The superior division accompanies the posterior circumflex artery around the neck of the humerus, and gives off a number of stout twigs which enter the deltoid muscle (fig. 755) . A few fine filaments pierce the deltoid and end in the integument which covers the middle third of that muscle.
The inferior division divides into cutaneous and muscular branches. The cutaneous branch (the lateral brachial cutaneous nerve) turns around the posterior border of the deltoid, pierces the deep fascia, and supplies the skin covering the lower third of the deltoid and a small area of integument below the insertion of the muscle (fig. 756). One muscular branch is distributed to the teres minor; it ' swells out into an ovoid or fusiform, reddish, gangliform enlargement before entering the muscle. Other branches supply the lower and posterior part of the deltoid.
The radial (musculo-spiral) nerve is the largest branch of the brachial plexus. It contains fibres from the sixth, seventh, and eighth cervical and sometimes from the fifth cervical and first thoracic nerves (figs. 751, 754). It commences at the lower border of the pectoralis minor, as the direct continuation of the posterior cord of the brachial plexus, and passes downward and lateralward in the axillary fossa behind the third part of the axillary artery (fig. 755) and in front of the subscapulars, latissimus dorsi, and teres major muscles. From the lower border of the axillary fossa it descends into the arm, where it lies, at' first, on the medial side of the upper third of the humerus, behind the brachial artery and in front of the long head of the triceps ; then it runs obliquely downward and lateralward behind the middle third of the humerus, in the groove for the radial nerve (musculo-spiral groove), and between the lateral and medial heads of the triceps. It is accompanied, in this part of its course, by the profunda artery. At the junction of the middle and lower thirds of the humerus it reaches the lateral side of the arm, pierces the external intermuscular septum, and runs downward and forward between the brachio-radialis and extensor carpi radialis longus externally, and the brachialis internally (fig. 758), and it terminates, a short distance above the capitulum, by dividing into deep and superficial terminal branches. In the last part of its course it is accompanied by the anterior terminal branch of the profunda artery.
Branches. — The branches of the radial or musculo-spiral nerve are cutaneous, muscular, articular^ and terminal, but for practical purposes it is best to consider them in association with the situations of their origins. While it is in the axillary fossa the radial (musculo-spiral) nerve gives branches to the medial and long heads of the triceps (fig. 758), and a medial cutaneous branch. The branch to the long head of the triceps at once enters the substance of the muscle, that to the medial head breaks into branches which terminate in the muscle at different levels, and one of them, the ulnar collateral nerve, accompanies the ulnar nerve to the lower part of the arm. The posterior brachial (internal) cutaneous branch crosses the tendon of the latissimus dorsi, passes dorsal to the intercosto-brachial (intercosto-humeral) nerve, pierces the deep fascia, and is distributed to the skin of the middle of the back of the arm below the deltoid.
While it lies behind the middle third of the humerus, the radial nerve gives branches to the lateral and medial heads of the triceps and to the anconeus. The latter branch descends in the substance of the median head of the triceps, close to the bone, and it is accompanied by a small branch of the profunda artery. The dorsal antibrachial (external) cutaneous branch, passing down between the lateral and median heads of the triceps, divides near the elbow into its upper and lower branches (fig. 756), each of which perforates either the lateral head of the triceps muscle near its attachment to the humerus or the external intermuscular septum.
The upper branch, much the smaller, pierces the deep fascia in the line of the external intermuscular septum; it accompanies the lower part of the cephaUc vein, and supphes the skin over the lower half of the lateral and anterior aspect of the arm. The lower branch is of considerable size. It pierces the deep fascia a httle below the upper branch, runs behind the external condyle, and supplies the skin of the middle of the back of the forearm as far as the wrist, anastomosing with the medial antibrachial (internal) cutaneous and musculo-cutaneous nerves (fig. 759).
After the radial nerve has pierced the external intermuscular septum it gives branches to the brachio-radialis, extensor carpi radialis longus, and to the lateral portion of the brachialis (fig. 759). From one of these branches an articular filament is distributed to the elbow-joint.
The deep radial [ramus profundus] (posterior interosseous) nerve runs downward in the interval between the brachialis and extensor carpi radialis longus. It passes in front of the lateral part of the elbow-joint, and after giving off branches to supply the extensor carpi radialis brevis and supinator, it is crossed in front by the radial recurrent artery (fig. 759) . It then runs downward and dorsalward through the substance of the supinator, and enters the interval between the superficial and deep layers of muscles at the back of the forearm, where it comes into relation with the posterior interosseous artery, and accompanies it across
the extensor indicis proprius.
Continuing distalward as the dorsal antibrachial interosseous nerve the deep radial leaves the posterior interosseous artery, dips beneath the e.xtensor pollicis longus, and joins the volar interosseous artery. It accompanies this artery upon the interosseous membrane and upon the back of the radius, passes through the groove for the extensor digitorum communis and extensor indicis proprius to the dorsum of the wrist, and terminates in a gangliform enlargement which gives branches to the carpal articulations. The muscles supplied by the deep radial nerve are the extensor carpi radialis brevis, brachio-radialis (supinator longus), extensor digitorum communis, extensor digiti quinti proprius, extensor carpi ulnaris, extensor indicis proprius, and the extensor muscles of the thumb. The supinator (brevis) receives two twigs, one of which is given off before the nerve pierces the muscle and the other while it is passmg through it.
The superficial radial (radial) nerve [ramus superficialis n. radialis] is somewhat smaller than the deep radial (posterior interosseous), and is a purely cutaneous nerve. It runs downward under cover of the brachio-radialis, passing in front of the elbow-joint, the radial recurrent artery, and the supinator (brevis). At the lower border of the supinator it approaches the radial artery at an acute angle, and runs parallel to the lateral side of that vessel in the middle third of the forearm, across the pronator teres. At the lower border of the pronator teres it bends dorsalward on the deep surface of the tendon of the brachio-radialis, and appears on the back of the forearm. It pierces the deep fascia and is directed across the dorsal carpal (posterior annular) ligament toward the dorsum of the wrist, where it divides into its terminal branches (fig. 759).
The most lateral of these branches suppUes the skin on the radial part of the thenar eminence; the most medial, designated the ulnar anastomotic branch, communicates with the'dorsal branch of the ulnar nerve. The other terminal branches, the dorsal digital nerves, supply to a variable extent the skin on the dorsum of the first digit, both sides of the second and the radial side of the third digit. These branches usually extend to the base of the nail of the first digit, to the distal interphalangeal joint of the second, not quite to the proximal interphalangeal joint of the third, and to the metacarpo-phalangeal joint of the fourth digit.
The terminal branches of the lateral cord of the brachial plexus are the musculo-cutaneous and the lateral component of the median nei-ve. The latter nerve will be described with the medial cord.
The musculo-cutaneous nerve is composed of fibres derived chiefly from the anterior divisions of the fifth and sixth cervical nerves, together usually with some fibres from that of the seventh (figs. 751 and 754). The nerve to the coracobrachialis usually consists of two or three twigs given off from the nerve close to its origin before it enters the muscle (fig. 755). Sometimes, however, the fibres from the seventh cervical nerve pass directly to this muscle without joining the main trunk. The musculo-cutaneous nerve is placed at first close to the lateral sideof the axillary artery (fig. 755), but soon it leaves that vessel and, piercing the coraco-brachialis muscle, it passes obliquely downward and lateralward between the biceps and brachialis muscles. Soon after piercing the coraco-brachialis it gives off muscular branches to each head of the biceps and to the brachialis (fig. 758). It also gives twigs to the humerus, to the nutrient artery, and gives the chief supply to the elbow-joint. Below the branch to the brachialis the cutaneous portion of the nerve forms the lateral antibrachial cutaneous nerve (figs. 756, 758) . This portion continues downward between the biceps and brachialis, pierces the deep fascia at the lateral border of the former muscle a little above the bend of the elbow, receives a communication from the upper branch of the dorsal antibrachial (upper external) cutaneous branch of the radial (musculo-spiral) nerve, passes dorsal to the median cephalic vein, and divides into an anterior and a posterior branch.
The anterior branch runs downward on the lateral and anterior part of the forearm, supplying the integument of that region, and it terminates in the skin covering the middle part of the thenar eminence (fig. 759). A short distance above the wrist, after it has received a communicating twig from the superficial radial nerve, it gives off an articular branch to the carpal joints. This branch pierces the deep fascia and accompanies the radial artery to the dorsum of the wrist. The posterior terminal branch is small, and is directed downward and backward in front of the external condyle of the humerus, to be distributed to the skin on the lateral and posterior aspect of the forearm as low as the wrist (fig. 756). It anastomoses with the superficial radial and with the lower branch of the dorsal antibrachial (lower external) cutaneous branch of the radial nerve.
The terminal branches of the medial cord of the brachial plexus are the ulnar nerve and the medial component of the median nerve. Neither of these gives any branches in the upper arm, and thus they differ from the other terminal branches of the plexus. They both supply the muscles and joints of the forearm, and the muscles, joints, and integument of the hand.
The ulnar nerve, which is the largest branch of the medial cord of the brachial plexus, contains fibres from the anterior divisions of the eighth cervical and first thoracic nerves (figs. 752 and 762). It commences at the lower border of the pectoralis minor and runs downward in the axillary fossa in the posterior angle between the axillary artery and vein. In the upper half of the arm it lies on the medial side of the brachial artery (fig. 755), but at the level of the insertion of the
coraco-brachialis it passes backward at an acute angle, and, accompanied by the superior ulnar collateral (inferior profunda) artery, it pierces the internal intermuscular septum. After passing through the septum it runs downward, in a groove in the medial head of the triceps (fig. 758), to the interval between the olec-
Flexor carpi radialis
ranon process and the medial condyle of the humerus, and in this part of its course it is closely bound to the muscle by the deep fascia. Immediately below the medial condyle it passes between the two heads of the flexor carpi ulnaris, along the medial side of the medial collateral ligament of the elbow, and it comes into relation with the dorsal ulnar recurrent artery.
In the upper forearm the ulnar nerve has on the flexor digitorum profundus, covered by the flexor carpi uhiaris. Near the junction of the upper and middle thirds of the forearm it is joined by the ulnar artery, which accompanies it to its termination, lying throughout on its radial side (fig. 759). In the lower part of the forearm it still rests on the flexor digitorum profundus, but
between the flexor carpi ulnaris and flexor digitorum sublimis, and is covered only by skin and fascia. At a variable point in this part of the forearm, usually about 5 to S cm. (2 to 3 in.) from the carpus, the nerve divides into its two terminal branches, a dorsal branch to the dorsal aspect of the hand, and a volar branch to the volar aspect.
Branches. — ^The ulnar resembles the median nerve in not furnishing any branches to the upper arm. As it passes between the olecranon process and the medial condyle it gives off two or three fine filaments to the elbow-joint. In the upper part of the forearm it supplies the flexor carpi ulnaris and the medial portion of the flexor digitorum profundus, and in the lower half it gives off the three cutaneous branches. In the palm of the hand it supplies the integument of the hypothenar eminence, the fifth digit, and half of the fourth digit, and part of the skin of the dorsum. It also supplies the short intrinsic muscles of the hand with the exception of the abductor poUicis, the opponens, the lateral head of the flexor poUicis brevis, and the two lateral lumbricales.
profundus arise from the ulnar nerve in the upper third of the forearm.
Cutaneous branches. — About the middle of the forearm the ulnar nerve gives off two cutaneous branches: — one pierces the fascia and anastomoses with the volar branch of the medial antibrachial (internal) cutaneous nerve, and the other, the palmar cutaneous branch, runs downward in front of the ulnar artery (fig. 759) and is conducted by this vessel into the palm
thenar eminence, and ends in the integument covering the central depressed surface of the palm.
The dorsal or posterior cutaneous branch, usually the smaller of the terminal branches, arises about 5 cm. (2 in.) above the wrist-joint, and passes backward under cover of the flexor carpi ulnaris to reach the dorsal aspect of the wrist (fig. 761), where it gives off dehoate branches to anastomose with branches of the medial antibrachial (internal) cutaneous, the dorsal antibrachial (external) cutaneous branch of the radial (musculo-spiral), the lateral antibrachial cutaneous of the musculo-cutaneous nerve, and with branches of the superficial radial, and then divides into five branches, the dorsal digitals (fig. 757), which are distributed to the ulnar sides of the third, fourth, and fifth digits and the radial sides of the fourth and fifth digits. These branches usually extend on the fifth digit only as far as the base of the terminal phalanx, and on the fourth digit as far as the base of the second phalanx. The more distal parts of these digits are supplied by palmar digital branches of the ulnar nerve.
The volar branch, the other terminal branch of the ulnar nerve, continues its course between the flexor carpi ulnaris and flexor digitorum sublimis, on the medial side of the ulnar artery, to the wrist, where, on the lateral side of the pisiform bone, it divides into a superficial and a d£ep branch (figs. 759 and 761). The latter accompanies the deep branch of the ulnar artery into the interval between the abductor digiti quinti and flexor digiti quinti brevis, and then
passes through the fibres of the opponens digiti quinti to reach the deep surface of the flexor tendons and theu- synovial sheaths. It supphes the abductor and opponens digiti quinti, the flexor digiti quinti brevis, the third and fourth lumbricales, all the interossei, the adductors of the thumb, and the medial head, and occasionally the lateral head, of the flexor poUicis brevis. The superficial branch gives off a branch to supply the palmaris brevis muscle, an anastomosing branch to the median nerve, and then divides into two branches, the proper volar digital branch, which is distributed to the medial side of the fifth digit on its volar aspect, and the common volar digital branch, which passes underneath the palmar aponeurosis and divides into two branches, which supply the contiguous margins of the fourth and fifth digits. These branches usually supply also the dorsal surface of the second and third phalanges of the same digits.
The median nerve contains fibres of the sixth, seventh, and eighth cervical nerves and of the first thoracic, and sometimes of the fifth cervical nerve. The trunk is formed a little below the lower margin of the pectorahs minor, by the
union of two components, one from the medial and one from the lateral cord "of the brachial plexus (fig. 755). The medial component passes obliquely across the third part of the axillary artery, and in the upper part of the trunk the fibres of the two components are felted together. From its commencement the median nerve runs almost vertically through the lower part of the axillary fossa and through the arm and forearm to the hand.
In the fossa it hes lateral to the axillary artery and it is overlapped, on its lateral side, by the cqraco-brachiahs muscle. In the upper half of the arm it lies along the lateral side of the brachial artery, and it is overlapped by the medial border of the biceps. At the middle of the arm it passes in front of the brachial artery, and then it descends, on the medial side of the artery, to the elbow. In the upper part of the antecubital fossa it is still at the medial side of the brachial artery, but separated from it by a small interval, and in the lower part of the fossa it Lies
along the medial side of the ulnar artery. In case of the high division of the brachial artery, when the radial and the ulnar arteries lie together in the upper arm, the median nerve may pass between them and then one or the other of the arteries will be superficial to the nerve. As it leaves the antecubital fossa it passes between the two heads of the pronator teres, and it crosses in front of the ulnar artery (fig. 759), from which it is separated by the deep head of the pronator. In the forearm it passes vertically downward, accompanied by the median (comes nervi mediani) artery. In the upper two-thirds of this region it lies deeply, between the flexor digitorum sublimis and the flexor digitorum profundus, but in the lower third it becomes more superficial, and is placed beneath the deep fascia, between the flexor carpi radialis on the radial side and the palmaris longus and flexor digitorum sublimis tendons on the ulnar side. It crosses beneath the transverse carpal (anterior annular) ligament, in front of the flexor tendons, and in the palm at the lower border of the ligament it enlarges and divides into three branches, the common volar digital nerves (fig. 760).
Branches. — The median nerve does not supply any part of the upper arm. In front of the elbow-joint it furnishes one or two filaments to that articulation. In the forearm it supplies all the superficial anterior muscles (with the exception of the flexor carpi ulnaris) directly from its trunk, and it supplies the deep muscles (with the exception of the ulnar half of the flexor digitorum profundus) by its volar (anterior) interosseous branch. Thus in general it supplies the pronator and flexor muscles of the forearm (radial side). In the hand it supplies the group of short muscles of the thumb, which are placed on the radial side of the tendon of the flexor pollicis longus, the two lateral lumbricales, the integument covering the central, part of the palm and ulnar aspect of the thenar eminence, and the palmar aspect of the first, second, third, and radial half of the fourth digits. It also sends twigs to the dorsal aspect of these digits.
The nerves to the flexor carpi radialis, palmaris longus, and flexor digitorum sublimis arise a Uttle lower down, and pierce the pronator-flexor mass of muscles to end in the respective members of the group for which they are destined (fig. 758).
The volar (anterior) interosseous nerve arises from the median at the level of the bicipital tubercle of the radius (fig. 759), and runs downward, on the interosseous membrane, accompanied by the volar (anterior) interosseous artery. It passes under cover of the pronator quadratus, and pierces the deep surface of that muscle, which it supplies. The volar interosseous nerve also furnishes a twig to the front of the wrist-joint, and supphes the flexor digitorum profundus and the flexor poUicis longus. The nerve to the former muscle arises from the volar interosseous near its commencement; it supplies the outer two divisions of the muscle, and it communicates within the substance of the muscle with twigs derived from the ulnar nerve.
It also supphes a branch to the interosseous membrane which runs downward upon, or in, the membrane, supplying it and giving branches to the volar (anterior) interosseous and nutrient arteries and to the periosteum of the radius, the ulna, and the carpus.
The palmar cutaneous branch arises immediately above the transverse carpal (anterior annular) ligament and passes between the tendons of the flexor carpi radialis and the palmaris longus (fig. 759). It then crosses the superficial surface of the transverse carpal ligament, and is distributed to the integument and fascia on the central, depressed surface of the palm. It also supplies a few twigs to the medial border of the thenar eminence; these twigs communicate with the musculo-cutaneous and superficial radial nerves.
The three common volar digital nerves pass in the palm of the hand dorsal to the superficial palmar arch and its digital branches, while the proper volar digitals, branches of these nerves, lie on the volar side of the digital arteries.
The first of the common volar digital nerves gives off a branch to supply the abductor pollicis, the opponens, and the superficial head of the flexor pollicis brevis, and joins by a delicate branch with the deep branch of the ulnar nerve. It then divides into three proper volar digitals (fig. 761). The lateral of these passes obhquely across the long flexor tendon of the thumb and runs along the radial border of the thumb to its extremity. It gives numerous branches to the pulp of the thumb, and a strong twig which passes to the dorsum to supply the matrix of the nail. The second of these proper volar digitals supplies the medial side of the volar aspect of the thumb and gives off a twig to the matrix of the thumb nail. The third supplies the radial side of the second digit and gives a twig to the flrst lumbrical muscle.
The second common volar digital sends a twig to the second lumbrical muscle, and divides a httle above the metacarpo-phalangeal articulation into two proper volar digitals, which respectively supply the adjacent sides of the second and third digits.
The third common volar digital communicates with the ulnar nerve, often gives a branch to the third lumbrical muscle, and divides into two proper volar digitals which supply the adjacent sides of the third and fourth digits.
As the proper volar digitals pass along the margins of the fingers they give off twigs for the innervation of the skin on the dorsum of the second and third phalanges and the matrix of their nails. Each of the nerves terminates in filaments to the pulp of the finger.
The anterior primary divisions of the thoracic nerves, with the exception of the first, retain, in the simplest form, the characters of anterior primary divisions of the typical spinal nerve. They do not form plexuses, but remain distinct from each other. Each divides into an easily recognisable lateral or dorsal and anterior or ventral branch (figs. 762 and 763), and they are not distributed to the limbs. The first, second, and last thoracic nerves, on account of their pecuUarities, require separate description. The remainder are separable into two groups, an upper and a lower. The upper group consists of four nerves, the third to the sixth inclusive, which are distributed entirely to the thoracic wall. The lower group contains five nerves, the seventh to the eleventh inclusive, which are distributed partly
The first thoracic nerve is connected with the first thoracic sympathetic ganglion, and it frequently is joined by a small branch with the second nerve. It is distributed chiefly to the upper limb. Opposite the superior costo-transverse ligament of the second rib it divides into a larger and a smaller branch; the larger passes upward and lateralward, between the apex of the pleura and the neck of the first rib, and on the lateral side of the superior intercostal artery, to the root of the neck, where it joins the brachial plexus. The smaller branch continues along the intercostal space, below the first rib and between the intercostal muscles in which, as a rule, all its fibres terminate.
However, the smaller branch may give off a lateral cutaneous branch which connects with the medial brachial (lesser internal) cutaneous nerve and with the intercosto-brachial nerve in the axillary fossa; and occasionally it terminates in an anterior cutaneous branch at the anterior extremity of the first intercostal space.
The second thoracic nerve, as it lies between the pleura and the superior costo-transverse ligament of the third rib, gives a branch to the first nerve, then it pierces the posterior intercostal membrane and passes between the external and internal intercostal muscles in the second intercostal space. In the dorsal part of the space it sends branches backward, through the external intercostal muscle,
to supply the second levator costse and the serratus posterior superior, and then it divides into a lateral and an anterior branch. The two branches run forward together to the mid-axillary line, where the lateral branch pierces the external intercostal muscle and passes between two digitations of the serratus anterior (magnus) into the axillary fossa; the anterior branch enters the substance of the internal intercostal muscle.
The lateral branch, the intercosto-brachial (intercosto-humeral) , may divide into a small anterior and a large posterior division, or the anterior division may be absent. In either case the lateral branch anastomoses with the medial brachial (lesser internal) cutaneous nerve, and usually with the lateral branch of the third intercostal nerve; it also anastomoses with the lateral branch of the first nerve, if the latter is present. After forming these junctions it passes out of the axillary fossa, pierces the deep fascia, and supplies the integument in the upper and posterior half of the arm. It also gives off a few filaments which terminate in the skin over the ajdllary border of the scapula. The size of the intercosto-brachial nerve and the extent of its distribution are usually in inverse proportion to the size of the other cutaneous nerves of the upper arm, especially the middle brachial (lesser internal) cutaneous. When the latter nerve is absent, the intercosto-brachial usually takes its place.
description.
The thoracic intercostal nerves (upper group). — The third, fourth, fifth, and sixth thoracic nerves, in the posterior parts of the intercostal spaces, give muscular branches to the levatores costarum, the first to the fourth also giving branches to the serratus posterior superior. They pass forward a short distance between the external and internal intercostals, giving twigs to these muscles, and divide into two branches, lateral and anterior.
The lateral cutaneous branches continue forward between the intercostal muscles, and, near the mid-axillary line, pierce the external intercostals and serratus anterior (magnus) and divide into two branches, posterior and anterior. The posterior branches pass backward over the latissimus dorsi to supply the skin in the lower part of the scapular region. The anterior branches, in the four nerves, increase in size from above downward. They pass around the lateral border of the great pectoral muscle and are distributed to the integument over the front of the thorax and m'anima, sending filaments, the lateral mammary branches, into the latter organ. The lowest two nerves also supply twigs to the upper digitations of the external oblique muscle.
The anterior branches run obliquely forward and medialward through the substance of the internal intercostal muscles, reaching the deep surface of these muscles at the extremity of the costal cartilages (fig. 762). They continue forward between these muscles and the pleura, pass in front of the internal ■ mammary artery, turn abruptly ventralward a short distance from the sternum, pierce the internal intercostals, the anterior intercostal membrane, and the pectoralis major, and give off three sets of terminal branches. One set supplies the transverse thoracic muscle and the back of the sternum. A second set, cutaneous, runs mesially. The third set passes laterally over the pectoralis major, supplying the skin in that region, and, in the female, the mammary gland through the medial mammary branches. The anterior branches in their course supply the intercostal and subcostal muscles and give filaments that supply the ribs, the periosteum, and the pleura.
The thoraco-abdominal nerves (lower group). — The relations of the posterior portions of the seventh, eighth, ninth, tenth, and eleventh thoracic nei'ves to the thoracic wall are similar to those of the upper thoracic intercostal nerves. Each divides in a similar manner into a lateral and an anterior branch, but these branches are distributed partly to the abdominal and partly to the thoracic wall, and the smaller muscular branches have also different distributions.
The lateral branches, lateral cutaneous nerves of the abdomen, pierce the external intercostal muscles and pass through or between the digitations of the external oblique into the subcutaneous tissue, where they divide in the typical way into anterior and posterior branches. The posterior branches pass backward over the latissimus dorsi. The anterior branches give filaments to the digitations of the external oblique and extend forward, medialward and downward to the outer border of the sheath of the rectus.
themselves between the interdigitating slips of the diaphragm and the transversus abdominis and enter the abdominal wall. The seventh, eighth, and ninth nerves, in their transit from the thoracic to the abdominal wall, pass behind the upturned ends of the eighth, ninth, and tenth rib-cartilages respectively. Having entered the abdominal wall the nerves run forward between the transversus abdominis and the internal oblique, muscles to the outer border of the rectus abdominis, where they pierce the posterior lamella of the internal oblique aponeurosis and enter the sheath of the rectus. In the sheath they pass through the substance of the rectus. Finally they turn directly forward, pierce the anterior part of the sheath, and become anterior cutaneous nerves of the abdomen.
The muscular branches. — Muscular branches from all the thoraco-abdominal nerves are distributed to the levatores costarum, the intercostal muscles, the transversus abdominis, the internal oblique, and to the rectus abdominis, and the ninth, tenth, and eleventh nerves gives branches also to the serratus posterior inferior. Branches are also distributed from a variable number of the lower nerves to the costal portions of the diaphragm.
The last thoracic nerve. — The anterior primary division of the last thoracic nerve is distributed to the wall of the abdomen and to the skin of the upper and front part of the buttock. It appears in the thoracic wall immediately below the last rib, where it communicates with the sympathetic cord and gives off a communicating branch to the first lumbar nerve. It passes from the thorax into the abdomen beneath the lateral lumbo-costal arch (external arcuate ligament), accompanied by the subcostal artery, and it runs across the upper part of the quadratus lumborum dorsal to the kidney and to the ascending or the descending colon according to the side considered. At the lateral border of the quadratus lumborum it pierces the aponeurosis of attachment of the transversus abdominis muscle and divides, between the transversus and the internal oblique muscle, into a lateral and an anterior branch. It gives branches to the transversus abdominis, the quadratus lumborum, and the internal oblique muscles.
The anterior branch passes forward, between the internal oblique and the transversus abdominis, to which it suppUes twigs. It enters the sheath of the rectus, turns forward through that muscle, and terminates in branches which become cutaneous midway between the umbilicus and the symphysis. Before it becomes cutaneous it supplies twigs to the transversus abdominis, the internal oblique, the rectus abdominis, and the pyramidalis muscles.
The lateral branch pierces the internal obhque; it supplies the lowest digitation of the external obhque, and then pierces the latter muscle from 2.5 to S cm. (1 to 3 in.) above the iliac crest, and descends in the superficial fascia of the anterior part of the gluteal region, crossing the ihac crest about 2.5 cm. (1 in.) behind its anterior extremity and reaching as far down as the level of the great trochanter. Occasionally this branch is absent and its place is taken by the iliac branch of the ilio-hypogastric. In such oases, however, the branch from the last thoracic to the first lumbar nerve is larger than usual.
The lumbo-sacral plexus is formed by the union of the anterior primary divisions of the lumbar, sacral, and coccygeal nerves. In about 50 per cent, of cases it receives a branch from the twelfth thoracic nerve. Its components are distributed to the lower extremity in a manner homologous and similar to the distribution of the parts of the brachial plexus to the upper extremity; the lumbar nerves are distributed similarly to the nerves formed from the anterior (medial and lateral) cords of the brachial plexus, and the sacral nerves are distributed in a manner similar to the distribution of the nerves from the posterior cord of the brachial plexus.
Partly for convenience of description and partly on account of the differences in position and course of some of the nerves arising from it, this plexus is subdivided into four parts — the lumbar, sacral, pudendal, and coccygeal plexuses. These plexuses overlap so that there is no definite line of demarcation between them. However, they will be considered separately.
part of the fourth and the fifth nerve commonly unite to form the lumbo-sacral cord which takes part in the formation of the sacral plexus (figs. 764, 765) . When the fourth nerve enters into the formation of both lumbar and sacral plexuses,
manner of its formation.
Owing to this variation three general classes of plexuses may be found, proximal or prefixed, ordinary, and distal or post-fixed. The basis of classification is the relation of the nerves of the limb to the spinal nerves which enter into their formation. The intermediate or slighter degrees of variation may consist only of changes in the size of the portions contributed by the diHerent spinal nerves to a given peripheral nerve, for a given nerve may receive a larger share of its fibres from a more proximal spinal nerve, and a smaller share from a more distal nerve, or vice versd. However, in the more marked degrees of variation the origin of a given peripheral nerve may vary in either direction to the extent of one spinal nerve. The more extreme types of the plexuses are sometimes associated with abnormal conditions of the vertebral column. It has been suggested that when the prefixed or proximal condition occurs, it indicates that the lower limb is placed a segment more proximal than in the ordinary cases, and when the distal condition is present, that the limb is arranged a segment more distal. Three types each of the proximal and the distal classes and one type of the ordinary class have been described by Bardeen. His statistics are made use of in the compilation of the following tables, in which are shown the range of variation and the common composition of each class of plexus: —
Furcal 4 L. 4 L. 4 L.
The lumbar plexus lies in the posterior part of the psoas muscle (fig. 765), in front of the transverse processes of the lumbar vertebrae and the medial border of the quadratus lumborum, and its terminal branches are distributed to the lower part of the abdominal wall, the front and medial part of the thigh, the external genital organs, the front of the knee, the medial side of the leg, and the medial side of the foot.
The first and second of the lumbar nerves give collateral muscular branches to the quadratus lumborum muscle, and the second and third nerves give similar branches to the psoas. The remaining branches of the plexus are terminal branches. The first lumbar nerve, after it has been joined by the branch from the last thoracic nerve, divides into three terminal branches, the ilio-hypogastric nerve, the ilio-inguinal nerve, and a branch which joins the second nerve. The fibres of this latter branch pass mainly into the genito-femoral (genito-crural) nerve, but occasionally some of them enter the femoral (anterior crural) and obturator nerves. The remaining nerves divide into anterior or ventral and posterior or dorsal divisions. The anterior divisions form a portion of the genitofemoral (genito-crural) nerve and the obturator nerve, and the posterior divisions enter the lateral (external) cutaneous and femoral (anterior crural) nerves.
All the terminal branches of the plexus are formed in the substance of the psoas muscle; four of them, the ilio-hypogastric, the ilio-inguinal, the lateral (external) cutaneous, and the femoral (anterior crural), leave the muscle at its lateral border. The genito-femoral (genito-crural) passes through its anterior surface, and the obturator through its medial border.
THE LUMBAR PLEXUS
from the last thoracic nerve, as it is in about 50 per cent, of the cases, and it thus contains fibres of both the last thoracic and the iirst lumbar nerves. It pierces the lateral border of the psoas and crosses in front of the quadratus lumborum (fig. 765), and behind the kidney and the colon. At the lateral border of the quadratus it pierces the aponeurosis of origin of the transversus abdominis and enters the areolar tissue between the transversus and the internal oblique, where it frequently communicates with the last thoracic and with the ilio-inguinal
respectively, with the lateral and anterior branches of a typical spinal nerve.
The anterior cutaneous (hypogastric) branch passes forward and downward, between the transversus abdominis and the internal oblique muscles, giving branches to both; it communicates with the ilio-inguinal nerve, and, near the anterior superior spine of the ilium, it pierces the internal oblique muscle and continues forward beneath the external obhque aponeurosis toward the middle line. About 2. .5 cm. (1 in.) above the subcutaneous inguinal ring it pierces the aponeurosis of the external oblique, becomes subcutaneous, and supplies the skin above the symphysis.
The lateral cutaneous (iliac) branch pierces the internal and external obhque muscles, emerging through the latter above the iUac crest at the junction of its anterior and middle thirds (fig. 769). It is distributed to the integument of the upper and lateral part of the thigh, in the neighborhood of the gluteus medius and tensor fasciae latae muscles (fig. 768).
The ilio-inguinal nerve arises principally from the first lumbar nerve, but it frequently contains fibres of the last thoracic nerve. It emerges from the lateral border of the psoas, at a lower level than the ilio-hypogastric nerve, and passes across the quadratus lumborum (figs. 765, 766). As a rule, it is below the level of the inferior end of the kidney, but it passes dorsal to the ascending or the descending colon according to the side considered, and crosses the posterior part of the inner lip of the iliac crest; it then runs forward on the upper part of the iliacus, pierces the transverus abdominis near the anterior part of the crest, and communicates with the anterior cutaneous (hypogastric) branch of the iliohypogastric nerve. A short distance below the anterior superior spine it passes through the internal oblique muscle, and then descends in the inguinal canal to the subcutaneous inguinal (external abdominal) ring, through which it emerges into the thigh on the lateral side of the spermatic cord (fig. 763). It is distributed to the skin of the upper and medial part of the thigh, in the male to the root of the penis and to the skin of the root of the scrotum through the anterior scrotal nerves (fig. 768), and in the female to the mons veneris and labium majus through the anterior labial nerves.
Not uncommonly the iho-inguinal nerve is blended with the iho-hypogastric nerve and separates from the latter between the transversus abdominis and the internal obUque muscles. It may be replaced by branches of the genito-femoral (genito-orural) nerve, or it may replace that nerve or the lateral cutaneous nerve.
The genito-femoral (genito-crural) nerve is connected with the first and second lumbar nerves, but the majority of its fibres are derived from the second nerve. It passes obliquely forwarcl and downward through the psoas and emerges from the anterior surface of that muscle, close to its medial border, at the level of the lower border of the third lumbar vertebra. After emerging from the substance of the psoas it runs downward on the anterior surface of the muscle (fig. 765), to the lateral side of the aorta and the common iliac artery, passes behind the ureter and divides into two branches, an external spermatic or genital, and a lumbo-inguinal or crural (fig. 766). Occasionally it divides in the substance of the psoas, and then the two branches issue separately through the anterior surface of the muscle.
The external spermatic (genital) branch runs downward on the psoas muscle, external to the external iliac artery; it gives a branch to the psoas, and at Poupart's hgament it turns around the inferior epigastric artery and enters the inguinal canal, accompanjdng the spermatic cord in the male or the round hgament in the female. It suppUes the cremaster muscle, and gives twigs to the integument of the scrotum (fig. 766) or the labium majus.
The lumbo-inguinal (crural) branch passes downward along the external ihac artery and beneath Poupart's hgament into the thigh, which it enters to the lateral side of the femoral artery. A short distance below Poupart's ligament it pierces the fascia lata or passes through the fossa ovalis (saphenous opening) and supplies the skin in the middle of the upper part of the thigh. A short distance below Poupart's hgament it sometimes sends branches to the anterior branch bf the lateral cutaneous nerve, and about the middle of the thigh it often joins with the cutaneous branches of the femoral (anterior crural) nerve.
The lateral cutaneous nerve receives fibres from the dorsal branches of the anterior primary divisions of the second and third lumbar nerves, and frequently some fibres from the first lumbar (fig. 769). It emerges from the lateral border of the psoas and passes obliquely across the iliacus dorsal to the iliac fascia, and dorsal to the caecum on the right side and the sigmoid colon on the left side, to a point immediately below the anterior superior spine of the ilium, where it passes below Poupart's ligament into the lateral angle of the femoral trigone (Scarpa's triangle). Leaving the trigone at once it passes through, behind, or in front of the sartorius and divides into two branches, anterior and posterior, which enter the deep fascia (fig. 766).
The posterior branch of the lateral cutaneous nerve breaks up into several secondary branches which become subcutaneous, and they supply the integument of the lateral part of the thigh, from the great trochanter to the level of the middle of the femur. The anterior branch runs downward in a canal in the deep fascia, for three or four inches, before it becomes subcutaneous. It usually divides into two branches, a lateral and a medial. The lateral branch supplies the skin of the lower half of the lateral side of the thigh, and the medial branch is distributed to the skin of the lateral side of the front of the thigh as far as the knee (fig. 766). Its lower filaments frequently unite with the cutaneous branches of the femoral (anterior
with them the patellar plexus.
The femoral (anterior crural) nerve is the largest terminal branch of the lumbar plexus. It is formed chiefly by fibres of the dorsal branches of the anterior primary divisions of the second, third, and fourth lunibar nerves, but it sometimes receives fibres from the first nerve also (figs. 765 and 769). It emerges from the lateral border of the psoas a short distance above Poupart's ligament, and descends in the groove between the psoas and the iliacus, behindPoupart's ligment, into
Pudendal plexus
the femoral trigone (Scarpa's triangle), where it lies to the lateral side of the femoral artery (fig. 767) , from which it is separated by some of the fibres of the psoas. In this situation it is flattened out and it divides into two series of terminal branches, the superficial and the deep. In general, they supply the muscles and skin on the anterior aspect of the thigh.
The terminal branches form two groups, the superficial and the deep. The superficial terminal branches are two muscular branches, the nerve to the pectineus, and the nerve to the sartorius, and two anterior cutaneous branches.
THE OBTURATOR NERVE 1003
The anterior (middle and internal) cutaneous nerves are best described separately. The middle cutaneous nerve soon divides into two branches, medial and lateral. The lateral branch pierces the sartorius and both branches become cutaneous about the junction of the upper and middle thirds of the tliigh (figs. 766, 768). They descend along the medial part of the front of the thigh to the knee, supplying the skin in the lower two-thirds of the medial part of the front of the thigh, and their terminal filaments take part in the formation of the patellar plexus. About the middle of the thigh the middle cutaneous is often joined by a twig with the lumboinguinal nerve (crural branch of the genito-crural nerve). The medial or internal cutaneous nerve runs downward and medialward along the lateral side of the femoral artery, to the apex of the femoral trigone (Scarpa's triangle), where it crosses in front of the artery and divides into an anterior and a posterior terminal branch. Before this division takes place, however, two or three collateral branches are given off from the trunk. The highest of these passes through the fossa ovalis (saphenous opening), or it pierces the deep fascia immediately below the opening, and supplies the skin as low as the middle of the thigh. The lowest pierces the deep fascia at the middle of the thigh and it descends in the subcutaneous tissue, supplying the skin on the medial side of the thigh from the middle of the thigh to the knee (figs. 768, 769). This nerve frequently varies in size inversely with the cutaneous branches of the obturator and saphenous nerves. The anterior branch of the internal cutaneous nerve passes vertically downward to the junction of the middle and lower thirds of the thigh, where it pierces the deep fascia. It still continues downward for a short distance, then it turns lateralward and passes to the front of the knee, where it enters into the patellar plexus.
The posterior branch descends along the dorsal border of the sartorius, and it gives off a branch which passes beneath that muscle to unite with twigs from the saphenous and from the superficial division of the obturator nerve, forming with them the subsartorial plexus which lies on the roof of the adductor (Hunter's) canal. At the medial side of the knee the nerve pierces the deep fascia and it descends to the middle of the calf (figs. 766, 768).
The deep terminal branches of the femoral nerve are six in number, one cutaneous branch, the saphenous, and five muscular branches. The branches radiate from the termination of the trunk of the femoral nerve, and thej^ are arranged in the following order from medial to lateral: — the saphenous nerve, the nerve to the vastus medialis, the nerve to the articularis genu (subcrureus) , the nerve to the vastus intermedins (crureus), the nerve to the vastus lateralis, and the nerve to the rectus femoris.
The saphenous nerve passes down through Scarpa's triangle along the lateral side of the femoral artery. At the apex of the triangle it enters the adductor (Hunter's) canal and descends through it, lying first to the lateral side, then in front, and finally to the medial side of the artery (fig. 767). After emerging from the lower end of the canal, accompanied by the superficial branch of the genu suprema (anastomotic) artery, it passes between the dorsal border of the sartorius and the anterior border of the tendon of the gracihs, and, becoming superficial, it enters into relationship with the great saphenous vein and descends with it along the inner border of the upper two-thirds of the tibia (fig. 768). It crosses the medial surface of the lower third of the tibia, passes in front of the internal malleolus, and runs forward along the medial border of the foot to the ball of the great toe.
Eierces the sartorius just above the knee and passes outward to the patellar plexus. After it ecomes superficial it supphes the integument on the medial side of the leg and foot, and it anastomoses, in the foot, with the medial dorsal cutaneous branch of the superficial peroneal (musculo-outaneous) nerve.
The nerve to the vastus medialis accompanies the saphenous nerve in the femoral trigone (Scarpa's triangle), lying to its outer side. At the upper end of the adductor canal it passes beneath the sartorius, external to the roof of the canal, and enters the medial surface of the vastus medialis. It sends a twig down to the knee-joint.
The nerve to the articularis genu (subcrureus), usually a terminal branch of the femoral, frequently arises from the nerve to the vastus intermedins. It passes between the vastus medialis and the vastus intermedins to the lower third of the thigh, where it supplies the articularis genu and sends a branch to the knee-joint.
The nerve to the vastus lateralis pas.ses downward behind the rectus and along the anterior border of the vastus lateralis accompanied by the descending branch of the lateral circumfiex artery. It also sends a branch to the knee-joint.
The obturator nerve contains fibres from the anterior primary divisions of the second, third, and fourth lumbar nerves, but its largest root is derived from the third nerve (figs. 765, 769). It sometimes receives fibres from the first and third lumbar nerves. It emerges from the medial border of the psoas at the dorsal part of the brim of the pelvis, where it lies in close relation with the lumbo-sacrai trunk of the plexus, from which it is separated by the iho-lumbar artery. Immediately after its exit from the psoas it pierces the pelvic fascia, crosses the
lateral side of the internal iliac vessels and the ureter, and runs forward in the extraperitoneal fat, below the obliterated hypogastric artery and along the upper part of the medial surface of the obturator internus to the upper part of the obturator foramen, where it passes through the obturator canal below the socalled horizontal ramus of the pubis and above the obturator membrane, into the upper part of the thigh. It is accompanied in the pelvis and the obturator canal by the obtm-ator arterj^, which lies at a lower level than the nerve, and it divides
medial aspect of the leg.
The anterior branch of the obturator has a twig joining it with the accessory obturator nerve, if that nerve is present, and then descends behind the pectineus and adductor longus and in front of the obturator externus and adductor magnus muscles (fig. 767). Its branches are: —
THE LUMBOSACRAL TRUNK
than usual, and it then descends, along the dorsal border of the sartorius, to the medial side of the knee, where it enters the subcutaneous tissue, and, proceeding downward, supplies the skin on the medial side of the leg as far as the middle of the calf. Twigs join it with the saphenous.
The posterior branch of the obturator (fig. 767) pierces the upper part of the obturator externus and passes downward between the adductor brevis and adductor magnus. Its branches are: —
1. Muscular branches to the obturator externus, to the oblique fibres of the adductor magnua and to the adductor brevis when the latter is not entirely suppUed by the anterior branch. The branch to the obturator externus is given off in the obturator canal.
Deep peroneal
magnus, or it passes through the opening for the femoral artery. In the popliteal space it descends on the popUteal artery to the back of the joint, where it pierces the posterior hgament, and its terminal filaments are distributed to the crucial ligaments and the structures in their immediate neighbourhood. This branch is not uncomraoulj' absent. Occasionally the posterior branch of the obturator nerve also supples a twig to the hip-joint.
The accessory obturator nerve arises from the third or fourth or from the third and fourth lumbar nerves, in the angles between the roots of the femoral (anterior crural) and obturator nerves. It is present in about twenty-nine per cent, of all cases (Eisler). It is often closely associated with the obturator nerve to the level of the brim of the pelvis, but instead of passing through the obturator foramen, it descends along the medial border of the psoas, crosses the anterior part of the brim of the pelvis, passes beneath the pectineus, and terminates in three main branches. One of these branches joins the anterior division of the obturator nerve, another supplies the pectineus, and the third is distributed to the hip-joint.
(figs. 765, 769). Sometimes the larger part of the fourth nerve may help to form the trunk. It may receive fibres from the third lumbar nerve or be formed entirely from the fifth. At its formation it is situated on the ala of the sacrum under cover of the psoas. It descends into the pelvis, and, as it crosses the anterior border of the ala of the sacrum, it emerges from beneath the psoas at the medial side of the obturator nerve, from which it is separated by the ilio-lumbar artery. It passes behind the common iliac vessels and unites with the first and second sacral nerves, forming with them the upper trunk of the sacral plexus.
The anterior primary divisions of the upper four sacral nerves enter the pelvis through the anterior sacral foramina and they diminish in size progressively from above downward. The first sacral is the largest of the spinal nerves, the second is slightly smaller than the first, while the third and fourth are relatively small. The fifth sacral nerve is still smaller than the fourth; it enters the pelvis between the sacrum and the coccyx. The anterior divisions of these nerves enter into the formation of three parts of the lumbo-sacral plexus, the sacral, pudendal, and coccygeal.
Sacral Plexus
The sacral plexus shows in its formation variations similar to those of the lumbar plexus; hence there are also seven types of this plexus, three of them belonging to the prefixed or proximal class, three to the postfixed or distal class, and one to the ordinary class. The following tables show the range of variation and the common arrangement in these classes: — •
The ordinary type of sacral plexus is commonly formed by the smaller part of the anterior division of the fourth lumbar nerve and the entire anterior division of the fifth lumbar nerve, together with the first and parts of the second and third sacral nerves.
The plexus lies in the pelvis on the anterior surface of the piriformis (fig. 765) and behind the pelvic fascia and the branches of the hypogastric (internal iliac) artery. It is also dorsal to the coils of intestine, the lower part of the ilio-pelvic colon lying in front of the left plexus, and the lower part of the ileum in front of the right plexus.
Cutaneous branches. — (a) The posterior femoral cutaneous (small sciatic) nerve arises partly from the anterior and partly from the posterior branches of the anterior primary divisions of the first, second, and third sacral nerves. It lies on the back of the plexus (figs. 765, 769), leaves the pelvis at the lower border of the piriformis, and descends in the buttock between the gluteus maximus and the posterior surface of the sciatic nerve (fig. 770). At the lower border of the gluteus maximus it passes behind the long head of the biceps femoris, and descends, immediately beneath the deep fascia, through the thigh and the upper part of the popliteal space (fig. 740). At the lower part of the popliteal region it perforates the deep fascia, and it terminates in branches which are distributed to the skin of the calf.
Branches of the small sciatic. — 1. Perineal branches are distributed in part to the skin of the upper and medial sides of the thigh on its dorsal aspect. One of the branches, kno\\Ti as the long pudendal nerve, runs forward and medialward in front of the tuberosity of the ischium to the lateral margin of the anterior part of the perineum, where it perforates the fascia lata and CoUes' fascia and enters the anterior compartment of the perineum. In the perineum twigs join it with the superficial perineal nerves, and its terminal filaments are distributed to the skin of the scrotum in the male, and to the labium majus in the female.
2. Inferior clunial (gluteal) branches, two or three in number, are given off beneath the gluteus maximus; they turn around the lower border of this muscle and are distributed to the skin of the lower and lateral part of the gluteal region.
In case of the separate origin of the tibial (internal popliteal) and common peroneal (external popliteal) nerves, the posterior femoral cutaneous (small sciatic) also arises from the sacral plexus in two parts. The ventral portion descends with the tibial nerve below the piriformis and gives off the perineal branches and medial femoral branches, while the dorsal portion passes through that muscle with the common peroneal nerve, and furnishes the gluteal and lateral femoral branches.
(6) The inferior medial clunial (perforating cutaneous) nerve arises from the posterior portion of the second and third sacral nerves (figs. 765, 769). It perforates the lower part of the sacro-tuberous (great sciatic) ligament, turns around the inferior border of the gluteus maximus, and is distribtued to the skin over the lower and medial part of that muscle. It is sometimes associated at its origin with the pudic nerve. It is not always present. Its place is sometirnes taken by a small nerve (the greater coccygeal perforating nerve of Eisler), arising from the third and fourth or fourth and fifth sacral nerves, and sometimes it is represented by a branch of the posterior femoral cutaneous.
(b) The superior gluteal nerve receives fibres from the posterior branches of the fourth and fifth lumbar, and the first sacral nerves. It passes out of the pelvis through the great sciatic foramen, above the upper border of the piriformis, and it is accompanied by the superior gluteal artery. As soon as it enters the buttock it divides into two branches, an upper and a lower.
1. The upper branch is the smaller. It accompanies the upper branch of the deep division of the superior gluteal artery below the middle curved line of the ihum, and it ends entirely in the gluteus medius (fig. 770).
2. The lower branch, larger than the upper, passes forward across the middle of the gluteus minimus, with the lower branch of the gluteal artery; it supphes the gluteus medius and the gluteus minimus, and it ends in the medial and posterior part of the tensor fasoias latse.
(c) The inferior gluteal nerve is formed by fibres from the posterior branches of the fifth lumbar, and the first and second sacral nerves. It passes through the great sciatic foramen, below the piriformis, and divides into a number of branches which end in the gluteus maximus (figs. 765, 769).
(d) The nerve of the quadratus femoris is formed by the anterior branches of the fom'th and fifth lumbar and the first and second sacral nerves. It lies on the front of the plexus and issues from the pelvis below the piriformis. In the buttock it lies at first between the sciatic nerve and the back of the ischium, and, at a lower level , between the obtxu-ator internus with the gemelli and the ischium . It terminates in the anterior surface of the quadratus femoris, having previouslj^ given off a branch to the hip-joint and another to the inferior gemellus.
(e) The nerve of the obturator internus is formed by the anterior branches of the fifth lumbar, and the first and second sacral nerves (figs. 765, 769). It leaves the pelvis below the pii-iformis, and crosses the spine of the ischium on the
lateral side of the internal pudic artery and on the medial side of the sciatic nerve. It gives a branch to the gemellus superior, and turns forward through the small sciatic foramen into the perineum, where it terminates in the inner surface of the obturator internus.
The sciatic nerve [n. ischiadicus]. — -The sciatic is not only the largest nerve of the sacral plexus, but it is also the largest nerve in the body. Its terminal branches are chiefly muscular, though some of its fibres are cutaneous. Although it is referred to as one trunk, it consists in reality of peroneal (lateral) and tibial (medial popliteal) portions, which are bound together by a sheath of fibrous tissue as far as the upper end of the popliteal space. In about 10 per cent, of the cases the two parts remain separate, and in such cases the peroneal (lateral popliteal)
The peroneal portion of the nerve consists of fibres derived from the dorsal branches of the anterior primary divisions of the fourth and fifth lumbar and the first and second sacral nerves, while the tibial part is formed by the fibres from the anterior branches of the fourth and fifth lumbar, and the first, second, and third sacral nerves (figs. 765, 769). ^ The common trunk leaves the pelvis by passing through the great sacro-sciatic foramen, usually below the piriformis, and descends through the buttock, running midway between the tuber ischii and the great trochanter (fig. 770). Passing down the thigh, the trunk terminates at the upper angle of the popliteal space by dividing
The relation of the trunk to the piriformis muscle is more or less unique. It may pass either above or below the muscle, it may spht and pass around the muscle, or the muscle may be spUt and surround the nerve. Again, there may be a sphtting of both the muscle and the nerve, in which case any possible combination of the four parts may occur; a portion of the nerve may be above and a portion between the parts of the muscle, or a portion may be below and a portion between. The trunk of the nerve hes deeply in the thigh, and it is covered posteriorly by the skin and fascia, the gluteus maximus and the long head of the biceps femoris. Anteriorly it is in relation, from above downward, with the following structures: — the posterior surface of the ischium and the nerve to the quadratus femoris, the gemellus superior, obturator internus, gemellus inferior, quadratus femoris, and adductor magnus muscles.
nished to the short head of the biceps.
The branch to the short head of the biceps femoris is derived from the peroneal (lateral popliteal) portion of the nerve, while all the other muscular branches are given off by the tibial (medial pophteal) part. The semitendinosus receives two branches, one which enters it above and another which passes into it below its tendinous intersection. The nerve to the long head of the biceps descends along the sciatic trunk and enters the middle of the deep surface of the muscle. The nerves to the semimembranosus and adductor magnus arise by a common trunk ' which divides into three or four branches. One branch ends in the adductor, and the others are distributed to the semimembranosus. The branch to the adductor magnus supplies only those fibres of the muscle which begin from the tuberosity of the ischium and descend vertically to the medial condyle of the femur.
At the apex of the popliteal space the two component parts of the common trunk of the sciatic become distinct. The tibial nerve (internal popliteal) , formed by fibres from the anterior branches of the fourth and fifth lumbar and first, second, and third sacral nerves, passes vertically through the popliteal space, descends through the leg to a point midway between the medial malleolus and the most prominent part of the medial tubercle of the os calcis, where it divides into its terminal branches, the lateral plantar and the medial plantar nerves. The part of the nerve from the point of bifurcation to the lower border of the popliteus muscle is sometimes called the internal popliteal; the part of the nerve in the dorsum of the leg being then designated the posterior tibial nerve.
In the upper part of the pophteal space the tibial nerve lies relatively superficially, being covered dorsally by the skin and fascia, while in the lower part of the space it is overlapped by the heads of the gastrocnemius and is crossed by the plantaris. In the upper part of the space it lies in front of the posterior femoral cutaneous (small sciatic) nerve and to the lateral side of the vein and artery; at the middle of the space it is dorsal and in the lower part of the space it is medial to both of them.
cutaneous, and muscular.
The articular branches are usually three in number, a superior and an inferior internal articular and an azygos articular. They accompany the corresponding arteries, and, after piercing the ligaments, are distributed in the interior of the joint. The superior branch is often wanting.
The cutaneous branch, the medial sural cutaneous (tibial communicating) nerve, descends between the heads of the gastrocnemius, beneath the deep fascia, to the middle of the calf, where it pierces the fascia and unites with the peroneal anastomotic branch of the lateral sural cutaneous to form the sural (external saphenous) nerve, through which its fibres are distributed to the skin of the lower and dorsal part of the leg and the lateral side of the foot.
the plantaris, soleus, and popliteus.
The nerve io the soleus is relatively large, and passes between the lateral head of the gastrocnemius and the plantaris before it reaches its termination (fig. 771). The nerve to the popliteus descends on the posterior surface of the muscle, turns around its lower border, and is distributed on its anterior aspect. In addition to supplying the popliteus, it gives articular branches to the knee and superior tibio-fibular joints, a branch to the tibia which accompanies the medullary artery, and a long, slender twig which gives filaments to the anterior and posterior tibial arteries, and it descends as the interosseous crural nerve on the interosseous membrane to the inferior tibio-fibular joint. It also gives branches to the interosseous membrane and to the periosteum of the lower part of the tibia.
Relations. — In the upper part of the leg the tibial nerve is placed deeply, under the gastrocnemius and soleus, but in the lower half it is merely covered by the deep fascia, which is thickened between the medial maleolus and the calcaneus to form the lacinate (internal annular) ligament, and the termination of the nerve lies either under cover of this hgament, or under the attachment of the abductor hallucis. The anterior relations of the nerve are, from above downward, the tibialis posterior, the flexor digitorum longus, the lower part of the tibia, and the posterior ligament of the ankle-joint. For a short distance after its commencement the nerve lies to the medial side of the posterior tibial artery; then it crosses behind the artery and runs downward along its lateral aspect.
The branches of the lower part of the tibial nerve (below the popliteal space) are likewise muscular, cutaneous, and articular. They are supplied to the deep muscles of the dorsum of the leg, to the fibula, to the skin of the heel and foot, and to the ankle-joint. Several of the terminal branches are important enough to receive special names and special treatment.
The muscular branches pass from the upper part of the nerve to the tibiahs posterior, flexor digitorum longus, soleus, and flexor haUuois longus. The fibular branch arises with the nerve to the flexor hallucis longus, and accompanies the peroneal artery. It supplies the periosteum and gives filaments which accompany the medullary artery.
The medial calcaneal (calcaneo-plantar cutaneous) nerves ai-ise from the trunk of the tibial nerve in the lower part of the leg. They pierce the laciniate (internal annular) ligament, and are distributed to the integument of the medial side and plantar surface of the heel and the adjoining part of the sole of the foot (fig. 771).
Terminal branches of tibial nerve. — The medial plantar nerve is the larger of the two terminal branches of the tibial nerve. It commences under cover of the lower border of the laciniate (internal annular) ligament, or under the posterior border of the abductor hallucis, and passes forward, accompanied by the small internal plantar artery, in the inter-muscular septum between the abductor hallucis and the flexor digitorum brevis. At the middle of the length of the foot it becomes superficial, in the interval between the two muscles, and divides into four sets of terminal branches (fig. 772) : —
the secondj third, and fourth, the common plantar digitals. Near the bases of the
Fig. 771. — Muscle Nerves of the Right Leg, viewed from Behind. (Spalteholz.) The semitendinosus, semimembranosus, biceps femoris, gastrocnemius, plantaris, soleus, and flexor hallucis longus have been wholly or in part removed.
toe. The second (common digital) nerve gives a twig to the first lumbrical and bifurcates to supply the adjacent sides of the first and second toes. The third supplies the adjacent sides of the second and third toes, and the fourth, after connecting with the superficial branch of the lateral plantar nerve, divides to supply the adjacent sides of the third and fourth toes. All the proper digital nerves run along the sides of the toes and he below the corresponding arteries; they supply the joints of the toes, and each gives off a dorsal branch to the skin over the second and terminal phalanges and to the bed of the nail. All of them give fibres terminating in numerous Pacinian corpuscles.
11 J medial plantar
ligament, or under cover of the origin of the abductor hallucis, and passes forward and lateralward to the base of the fifth metatarsal bone, where it divides into a superficial and a deep branch (fig. 772). As it runs forward and lateralward it it is superficial to the tendon of the flexor hallucis longus and to the quadratus plantse (flexor accessorius), and deep to the flexor digitorum brevis. At its termination it lies in the interval between the flexor digitorum brevis and abductor digiti quinti.
The superficial branch supplies muscular filaments to the flexor digiti quinti brevis, the opponens, the third plantar and fourth dorsal interosseous muscles, and divides into two common plantar digital nerves, each of which subdivides to form proper plantar digital nerves.
The lateral of the two common branches supplies the lateral side of the fifth digit; the medial connects with the lateral digital branch of the medial plantar nerve (fig. 772) and divides into proper plantar digital nerves for the adjacent sides of the fourth and fifth digits. The digital branches of the superficial division of the lateral plantar, like those of the medial plantar, supply the skin of the toes and the beds of the nails, and their fibres terminate in numerouos Pacinian corpuscles.
The deep branch passes forward and medialward into the deep part of the sole with the plantar arterial arch. It runs deep to the quadratus plantse, the long flexor tendons and the lumbricals, and the oblique adductor of the great toe. It lies, therefore, immediately beneath the bases of the metatarsal bones and it supplies the following muscular and articular branches: — •
metatarsal spaces, and the transverse and oblique adductor muscles of the great toe.
Articular branches to the intertarsal and to the tarso-metatarsal joints and not uncommonly to the metatarso-phalangeal joints also. Filaments from the deep branch frequently pass through the interosseous spaces and join with the interosseous branches of the deep peroneal (anterior tibial) nerve.
The common peroneal (external popliteal) nerve. — ^At the apex of the popliteal space, where the two component parts of the sciatic trunk usually become distinct, the lateral portion receives the name common peroneal nerve. It descends along the posterior border of the biceps femoris, which forms the upper part of the lateral boundary of the space (fig. 771). It leaves the space at the lateral angle, crosses the plantaris, the lateral head of the gastrocnemius, the popliteus, and the inferior external artery, and descends behind the upper part of the soleus, to the neck of the fibula, where it turns forward between the peroneus longus and the bone, and breaks up into its three terminal branches, the recurrent articular, the superficial peroneal (musculo-cutaneous), and the deep peroneal (anterior tibial) nerves (fig. 773).
The superior articular branch accompanies the superior external articular artery. The lateral head of the gastrocnemius, and it joins the inferior external articular artery behind the tendon of the biceps femoris. Both the upper and lower articular branches pierce the ligaments and are distributed in the interior of the knee joint.
The cutaneous branch {communicans fibularis) , lateral sural cutaneous, is extremely variable both as to the number of its branches and as to the place of its anastomosis with the medial sural cutaneous. Leaving the common peroneal (external popliteal) in the popliteal space, it descends between the deep fascia and the lateral head of the gastrocnemius to the middle of the calf, where it pierces the fascia and unites with the medial sural cutaneous to form the sural (external saphenous) nerve. In its course it may give off no branches; or it may give off several, some of which supply the skin of the dorsum of the leg, while one of them, the peroneal anastomotic branch, unites with the medial sural cutaneous to form the sural (short saphenous) nerve. The junction of the peroneal anastomotic branch with the medial sural cutaneous may take place at any point between the popliteal space and the lower third of the leg.
The sural (external or short saphenous) nerve is formed by the union of the lateral sural cutaneous nerve either directly, or tlu-ough a connecting branch, the peroneal anastomotic, with the medial sural cutaneous (fig. 771). It descends along the lateral border of the tendo Achillis, giving branches to the lower and lateral part of the leg, and lateral calcaneal branches to the lateral side of the heel. It passes dorsal to the lateral malleolus, turns forward across the lateral surface of the cruciate (external annular) ligament, and becomes the lateral dorsal cutaneous nerve. Continuing along the lateral side of the foot it divides into two branches, the dorsal digitals, one of which supplies the lateral side of the fifth digit, while the other anastomoses with or takes the place of a branch of the superficial peroneal (musculo-cutaneous) nerve, which is distributed to the adjacent sides of the fourth and fifth digits (fig. 773).
part of the attachment of the extensor digitorum longus. At the medial border of the fibula it becomes associated with the anterior tibial recmrent artery, with which it ascends through the upper part of the tibialis anterior to the head of the
(2) The superficial peroneal (musculo-cutaneous) nerve arises from the common peroneal between the peroneus longus and the neck of the fibula and descends in the intermuscular septum between the long and short peronei on the
THE DEEP PERONEAL NERVE 1015
lateral side, and the extensor digitorum longus on the medial side. It gives off muscular and cutaneous branches in its descent, and at the junction of the middle and lower thii-ds of the leg it pierces the deep fascia and divides into a medial and a lateral branch (fig. 773).
skin of the lower part of the front of the leg.
The medial dorsal cutaneous (internal cruciate branch of the superficial peroneal), passes downward and medialward across the transverse and the cruciate (anterior annular) ligament of the ankle and subdivides into two branches. The medial branch passes to the medial side of the great toe; it also supplies twigs to the skin of the medial side of the foot, and it anastomoses with the deep saphenous nerve and with the medial terminal branch of the deep peroneal (anterior tibial) nerve. The lateral branch passes to the base of the cleft between the second and third toes and divides into two dorsal digital branches which supply the adjacent sides of the cleft.
The lateral branch (intermediate dorsal cutaneous) of the superficial peroneal, in separating from the medial, crosses in front of the cruciate ligament and divides into two dorsal digital branches, which pass beneath the dorsal venous arch. The medial of these branches supplies the adjacent sides of the third and fourth toes (fig. 773). The lateral branch communicates with the sural (external saphenous) nerve and is distributed to the adjacent sides of the fourth and fifth toes. This latter branch is frequently replaced by the sural nei-ve.
(3) The deep peroneal (anterior tibial) nerve springs from the end of the common peroneal (external popliteal) nerve between the peroneus longus muscle and the neck of the fibula. It passes forward and medialward through the upper part of the origin of the extensor digitorum longus, to the interval between that muscle and the tibialis anterior; then it descends, in the anterior compartment of the leg, to the ankle, where it divides into a medial and a lateral terminal branch (fig. 773).
In the upper part of the leg the deep peroneal nerve lies between the extensor digitorum longus and tibialis anterior and lateral to the anterior tibial artery. In the middle of the leg it is in front of the artery and between the extensor hallucis longus and tibiaMs anterior; then it crosses beneath the extensor hallucis, and in the lower third of the leg it is again to the lateral side of the artery, but between the extensor hallucis longus and the extensor digitorum longus.
Terminal branches. — The medial terminal branch passes downward along the side of the dorsalis pedis artery and divides into two dorsal digital branches which supply the adjacent sides of the first and second toes. It also gives filaments to the periosteum of the adjacent bones, to the metatarso-phalangeal and interphalangeal articulations, a twig to the dorsal interosseous muscle of the first space, and a perforating twig which connects with the lateral plantar nerve. The lateral terminal branch passes lateralward, beneath the extensor digitorum brevis, and it ends in a gangliform enlargement from which branches are distributed to the extensor digitorum brevis, the tarsal joints, and to the three lateral intermetatarsal spaces. The latter branches supply the neighbouring bones, periosteum, and joints. They give off perforating twigs, which pass through the spaces and anastomose with branches of the lateral plantar nerve, and the most medial also gives a twig to the second dorsal interosseous muscle.
Pudic nerve 2,3 8. 2,3,4 8. 3, 4 S.
The pudendal plexus is commonly formed by parts of the anterior divisions of the second, third, and fourth sacral nerves. It lies in the lower part of the back of the pelvis, and gives off visceral, muscular, and terminal branches.
Visceral branches (pelvic splanchnics) arise from the third and fourth sacral nerves especially, and enter branches of the sympathetic plexus. They are distributed both directly (their afferent or sensory fibres terminating in the pelvic viscera) and by their visceral efferent fibres terminating in the ganglia of the sympathetic plexus to the pelvic viscera (figs. 765, 791). The middle hsemorrhoidal nerves pass to the rectum, the inferior vesical nerves to the bladder, and, in the female, the vaginal nerves to the vagina fsee Sympathetic System).
The nerves to the two former muscles pass into the pelvic surfaces of the muscles, but that to the last-named muscle, called the perineal branch, passes backward between the levator ani and the coccygeus, or through the posterior fibres of the latter muscle, into the posterior part of the ischio-rectal fossa, and, in addition to supplying the sphincter ani, it gives cutaneous filaments to the skin between the anus and the coccyx.
Terminal branches. — The pudic nerve [n. pudendus] rises usually from the anterior primary divisions of the second, third, and fourth sacral nerves (fig. 765). It emerges from the pelvis below the piriformis, crosses the spine of the ischium, lying to the medial side of the internal pudic artery (fig. 769), and accompanies the artery, through the small sciatic foramen, into Alcock's canal in the obturator fascia on the lateral wall of the ischio-rectal fossa, where it terminates by dividing into three branches, the inferior hsemorrhoidal, the perineal, and the dorsal nerve of the penis.
The inferior haemorrhoidal nerves frequently arise independently from the third and fourth sacral nerves, pierce the medial wall of Alcock's canal, and pass forward and medialward through the ischio-rectal fat to supply the sphincter ani externus and adjacent skin. They anastomose with branches of the perineal nerve.
The perineal nerve runs forward for a short distance in Alcock's canal and divides into a deep and a superficial branch. The deep branch breaks up into filaments, one or two of which pierce the medial wall of the canal and pass medialward to the anterior fibres of the sphincter and levator ani. The remaining part of the nerve pierces the base of the m-o-genital trigone (triangular ligament), and enters the superficial pouch of the urethral triangle, where it is distributed to the bulb of the urethra, and to the transversus perinei, bulbocavernosus, and ischiocavernosus. It also sends some sensory filaments to the mucous membrane of the urethra. The superficial branch almost at once divides into medial and lateral branches, the posterior scrotal (labial) nerves.
Both branches pass through the wall of Alcock's canal into the anterior part of the ischiorectal fossa, then they pierce the base of the uro-genital trigone, and enter the superficial pouch of the urethral triangle. The lateral branch usually passes below the transversus perinei, and the medial branch above the muscle or through its fibres. The lateral branch connects with the long pudendal nerve, and with the inferior hsemorrhoidal nerve, and both branches end in terminal filaments which anastomose and which are distributed to the skin of the scrotum and the anterior part of the perineum in the male, and to the labium majus in the female.
The dorsal nerve of the penis runs forward in Alcock's canal above the internal pudic artery. It pierces the base of the uro-genital trigone, continues forward between the layers of the trigone, embedded in the fibres of the constrictor urethrse, and it gradually passes to the lateral side of the internal pudic artery. A short distance below the pudic arch it pierces the anterior layer of the uro-genital trigone, gives a branch to the corpus cavernosum penis, passes forward between that structure and the bone, and turns downward on the dorsum of the penis, passing between the layers of the fundiform (suspensory) ligament and along the outer side of the dorsal artery of the penis. It supplies the skin of the dorsum of the penis, and, having given branches to the prepuce, it breaks up into terminal filaments which are distributed to the glans penis.
THE COCCYGEAL PLEXUS
This plexus is frequently, and with some reason, considered as a subdivision of the pudendal plexus, and sometimes it is described with the coccygeal nerves. It is formed chiefly by the anterior division of the fifth sacral nerve and the coccygeal nerve, but it receives a small filament from the anterior division of the fourth sacral nerve (figs. 765, 769). These constituents unite to form plexiform cords lying on either side of the coccyx. From these cords arise the ano-coccygeal nerves, which pierce the sacro-tuberous (great sacro-sciatic) ligament and supply the skin in the neighbourhood of the coccyx.
AND SPINAL NERVES
The cutaneous filaments of the sensory and mixed nerves are distributed to definite regions of the surface of the body which are known as 'cutaneous areas.' Each cutaneous area has one special nerve of supply and the central part of the area receives that nerve alone, but wherever the borders of two areas meet they reciprocally overlap, therefore each margin of every cutaneous area has two nerves of supply, its own nerve and that of an adjacent area, and of these, sometimes one and sometimes the other preponderates.
The Cutaneous Areas of the Scalp
The limits of the cutaneous areas in the scalp region are indicated in figs. 774, 776, but in general terms it may be said that the skin of the scalp in front of the pinna is supphed by four cutaneous nerves, viz. , the mesial part by the supratrochlear and the supra-orbital branches of the ophthalmic division of the trigeminus, and the lateral part by the temporal branch of the maxillary division, and the auriculo-temporal branch of the mandibular division of the same nerve.
The portion of the scalp behind the pinna also receives four cutaneous nerves; laterally it is supplied by the great auricular and small occipital branches of the cervical plexus which contain filaments from the second and third cervical nerves, and medially it receives the great and smallest occipital nerves which are derived from the internal branches of the posterior primary divisions of the second and third cervical nerves respectively.
With the exception of the skin over the posterior part of the masseter muscle, the whole of the skin of the face is supplied by the branches of the trigeminus. The nose is supplied medially by the supratrochlear, the infratrochlear, and the nasal branches of the ophthalmic division, and laterally by the infra-orbital branch of the maxillary division. The upper eyelid is supplied by the supratrochlear, the supra-orbital, and the lacrimal branches of the ophthalmic division; the lower eyelid by the infratrochlear branch of the ophthalmic division and by the infra-orbital and the zygomatico-facial (malar) branches of the maxillary division. The skin over the upper jaw and the zygomatic (malar) bone is supplied by the infra-orbital and zygomatico-facial branches of the maxillary division, that over the buccinator by the buccal branch of the mandibular division, and that over the lower jaw, fiom in front backward, by the mental, buccal, and auriculo-temporal branches of the mandibular division, except a small part near the posterior border which receives its supply from the great auricular nerve.
Obhque shading— Ascending and transverse superficial branches of cervical plexus. Transverse shadmg— Descending superficial branches of cervical plexus. It i^ult be remembered that the boundaries of each area are not distmct; wherever two areas meet they overlap.
auricular nerve. The lower three-fourths of the cranial surface of the pinna are supphed by the great auricular nerve, and the upper fourth by the small occipital nerve. The posterior surffce of the external auditory meatus receives filaments from the auricular branch of the vagus.
The skin over the anterior part of the neck is supplied by the superficial cervical branch of the cervical plexus, which contains fibres from the second and third cervical nerves and in the lower part of its extent, by the anterior supra-clavicular nerves (suprasternal branches).
which convey twigs of the third and fourth cervical nerves (fig. 774). The lateral part of the neck receives filaments from the second, third, and fourth cervical nerves by way of the great auricular, small occipital, and middle supraclavicular (supra-clavicular) branches of the cervical plexus, and posteriorly the skin of the neck is suppUed by the small occipital nerve and by the medial branches of the posterior primary divisions of the cervical nerves from the second to the sixth inclusive (fig. 776).
The skin over the ventral aspect of the trunk as far down as the third rib is supphed by the anterior supra-clavicular (suprasternal) and middle supra-olavicular (supra-clavicular) branches of the cervical plexus, which contain filaments from the third and fourth cervical nerves (fig: 776). From the third rib to tlie lower part of the abdominal wall the skin receives the anterior cutaneous branches, and the anterior divisions of the lateral cutaneous branches of
The cutaneous supply of the lateral aspects of the body is derived from the lateral branches of the anterior primary divisions of the thoracic nerves from the second to the eleventh, and the skin over the dorsal aspect of the body is supplied laterally by the posterior divisions of the lateral branches of the thoracic nerves from the third to the eleventh, and medially by the posterior primary divisions of the thoracic nerves, in the upper half by their medial branches and in the lower half principally by their lateral branches.
The areas of skin of the upper and lower limbs which are supplied by the branches of the brachial, lumbar, and sacral plexuses are indicated in fig. 776, and the spinal nerves which contribute to each nerve area are noted. The question of the skin areas supplied by any given spinal nerve is one of great chnical importance, in connection with the diagnosis of injuries of nerves and of pathological conditions affecting them. Therefore, considerable attention has been directed to the matter and it has been found that the areas which become hypersensitive when certain spinal nerve-roots are irritated, or anaesthetic when the roots are destroyed, do
Red — Ophthalmic division of trigeminus. White — maxillary division of trigeminus. Blue — mandibular division of trigeminus. Dotted area — Posterior primary divisions of cervical nerves. Oblique and transverse shading — Branches of cervical plexus.
Red — Anterior branches of anterior primary divisions.. Blue — Posterior branches of anterior primary divisions. Two colours in one area indicate that the area is supplied by two sets of nerves, and it should be remembered that wherever two nerve areas approach each other they overlap. The dotted blue area of the posterior femoral cutaneous (small sciatic) indicates that the nerve comes from the posterior as well as from the anterior parts of the anterior primary divisions of the sacral nerves, but it supplies a flexor area. The area of the inferior medial cluneal nerve is left uncoloured, because its true nature is uncertain. Dotted shading — posterior primary divisions. The numbers and initial letters refer to the respective spinal nerves from which the nerves are derived.
not correspond exactly with the regions to which the fibres of the roots can apparently be traced by dissection. Moreover, it has been discovered, partly by clinical observations on the human subject and partly by experiment on monkeys, that the nerves of the hmbs have a more or less definite segmental distribution. To understand clearly this segmental arrangement the reader must remember that in the embryonic stage when no limbs are present the body is formed of a series of similar segments, each of which is provided with its own nerve. At a later stage when the limbs grow outward, each limb is formed by portions of a definite number of segments which fuse together into a common mass of somewhat wedge-hke outline. Each rudimentary limb possesses a dorsal and a ventral surface. The dorsal surfaces of both the upper and the lower limbs are originally the extensor surfaces, and the ventral surfaces the flexor surfaces, but, as the upper limb rotates lateralward and the lower limb rotates medianward as development proceeds, in the adult, the extensor surface of the upper Umb becomes the posterior surface, and the extensor surface of the lower limb, the anterior surface. The preaxial border of the upper limb is the radial or thumb border, and the postaxial border, the ulnar or little finger border. The preaxial border of the lower hmb is the tibial or great toe border, and the postaxial border, the fibular or little toe border. As projections of the segments of the body grow out to form the limb-buds and limbs each projection carries with it the whole or part of the nerve of the segment to which it belongs, and therefore the number of body segments which take part in a hmb is indicated by the number of spinal nerves which pass into it. If these facts are remembered it will naturally be expected (1) that the highest spinal nerves passing into a hmb will be associated with its preaxial portion and the lowest with its post-
Postaxial border shaded.
axial portion; (2) that only the nerves of those segments forming middle or central portions of the limbs will extend to the tips of the hmbs; (3) that the highest and lowest segments in each hmb area wiU take a smaller part in the formation of the limb that the -middle segments; and (4) that, consequently, the highest and lowest nerves wiU pass outward into the limb for a shorter distance than the middle nerves. Observers are not yet in perfect agreement as to the exact distribution of each nerve, but the diagrams in figs. 775 to 781 show the embryonic derivation of the cutaneous areas and the adult dorso-ventral segmental arrangement in the projected portions of both the upper and lower limbs as assumed from clinical observations. In the upper parts of the lower limbs, the original segmental distributuion appears to be masked. This may be due (1) partly to the fact that the areas recognisable by clinical phenomena do not correspond exactly with the areas to which definite dorsal root-fibres are distributed, but rather to definite segments of the grey substance of the spinal cord with which the root-fibres are connected; (2) partly to the overlapping of segments and the acquired preponderance of one nerve over another in the overlapping areas, and (3) partly to the fact that in the lower hmb there has been a greater amount of shifting of parts to result in the fixed fiat position of the sole of the foot; (4) and partly to the incompleteness of the data which are at our disposal in the case of the human subject. Sherrington has proved that in the monkey the sensory areas of the limbs are arranged in serial correspondence with the spinal nerves, the middle nerves of each limb series passing to the distal extremity while the higher and lower nerves are limited to the proximal regions. Thorburn's observations, which differ from Head's, are, especially as regards the upper limb, in close conformity with the results obtained by Sherrington's experiments on monkeys.
Each limb may be divided into its preaxial and postaxial borders by a line drawn longitudinally along the middle of both its anterior and posterior surfaces (compare figs. 777 and 779) The cutaneous nerves to the preaxial border are from the cephalic portion of the hmb plexus, and those to the postaxial are from the caudal components of the plexus. Thus the thumb and index finger are cephalad.
A line passing along the middle of both the anterior and posterior surfaces of the upper extremity to the tip of the middle finger (fig. 779) separates the preaxial from the postaxial border and passes longitudinally along the area of the cutaneous fibres derived from the seventh cervical nerve.
The skin over the upper third of the deltoid muscle is supplied by the posterior supraclavicular (supra-acromial) and middle supra-clavicular (supra-clavicular) nerves, which are branches of the cervical plexus containing fibres of the third and fourth cervical nerves, and that over the lower two-thirds by the axillary (circumflex) nerve which conveys fibres of the fifth and sixth cervical nerves (fig. 776).
the external cutaneous branch of the radial (musculo-spiral) nerve. The former contains filaments of both the fifth and sixth cervical nerves, and the latter filaments of the sixth alone. The skin of the medial side of the upper arm is supplied by the medial antibrachial cutaneous (internal cutaneous) nerve with fibres of the eighth cervical and first thoracic nerves, and by the medial brachial cutaneous (lesser internal cutaneous) and intercosto-brachial (intercostohumeral) nerves which are derived from the first and second thoracic nerves. The dorsal side of the upper arm is supphed, laterally, by the fifth and sixth cervical nerves through the axillary
(circumflex) nerve and by the dorsal antibrachial cutaneous; the middle portion, by the seventh cervical nerve through the posterior brachial cutaneous, the internal cutaneous branch of the radial (musculo-spiral) nerve; and the medial portion by the first and second thoracic nerves through the medial brachial cutaneous (lesser internal cutaneous) nerve, and the intercostobrachial (intercosto-humeral) nerve (fig. 776).
brachial plexus; a middle which is supplied by the seventh cervical nerve as above, and a medial area supplied by the eighth cervical and first thoracic nerve through the medial antibrachial cutaneous (internal cutaneous) nerve. On the dorsal side of the forearm there are three areas: — (1) a lateral suppUed by fibres of the fifth and sixth cervical nerves through the musculocutaneous nerve; (2) a middle, which receives fibres of the seventh, and probably some from the sixth and eighth cervical nerves through the lower branch of the dorsal antibrachial cutaneous of the radial (inferior external cutaneous branch of the musculo-spiral nerve), and (3) a medial which receives the eighth cervical and first thoracic nerves through the medial antibrachial cutaneous (figs. 776, 779).
The palm of the hand is supplied by the sixth, seventh, and eighth cervical nerves through the superficial radial (radial) nerve, and through the median and ulnar nerves. The superficial radial supplies the radial side of the thumb by its palmar cutaneous branch. The remainder of the palm and the palmar aspects of the fingers are supplied by the median and ulnar nerves through their palmar cutaneous and digital branches, the median supplying three and a half digits and the ulnar the remaining one and a half (figs. 776 and 779).
The dorsal aspect of the hand is suppUed by the sixth, seventh, and eighth cervical nerves, which reach it through the superficial radial( radial) and through the median and ulnar nerves. The superficial radial supplies the lateral part of the dorsum and the lateral three and a half digits, except the lower portions of the second, third, and half of the fourth digits, which ■receive twigs from the median nerve; the ulnar nerve supplies the ulnar half of the dorsum of
The segmental arrangement of the cutaneous areas of the lower extremity is not so well retained as in the upper, due largely to a greater amount of developmental shifting of the parts. Both of the lines separating the areas of the lumbar (cephalic) and the sacral (caudal) parts of the lumbo-sacral plexus he on the dorsal aspect of the limb. The nerves from the lumbar part of the plexus are distributed to the entire anterior and the medial and lateral surfaces of the hmb and to the muscles of the anterior and medial portions of the thigh and the anterior portion of the leg, whereas the cutaneous nerves from the sacral part of the plexus are confined to a narrow strip along the dorsal aspect of the limb (fig. 781). However, the muscular distribution of the sacral part is as much expanded as its cutaneous area is contracted; it supplies the muscles in the dorsal portions of the hip, thigh and knee, the whole of the dorsal part of the leg and ankle and the plantar muscles of the foot.
There are six cutaneous areas in the region of the buttock, three upper and three lower. Of the upper areas the lateral is supplied by the anterior primary divisions of the last thoracic and first lumbar nerves through the iliac branches of the last thoracic and the iho-hypogastric nerves; the middle upper area receives the lateral divisions of the posterior primary branches of the upper three lumbar nerves, and the medial upper area is supplied by twigs from the lateral branches of the posterior primary divisions of the upper two or three sacral nerves (figs. 776, 780).
Of the lower three areas, the lateral receives filaments from the second and third lumbar nerves through the lateral femoral cutaneous (external cutaneous) branch of the lumbar plexus; the middle area is supplied by the first, second, and third sacral nerves through the posterior femoral cutaneous (small sciatic) nerve; and the medial area by the second and third sacral nerves through the medial inferior clunial (perforating cutaneous) branch of the sacral plexus (fig. 776).
On the back of the thigh there are three areas. According to Head, the medial and lateral areas are supphed by the second and third lumbar nerves, the former through the lateral femoral cutaneous (external cutaneous) branch of the lumbar plexus, and the latter through the anterior cutaneous branches of the femoral (internal cutaneous branch of the anterior crural) nerve. The middle area receives twigs from the first, second, and third sacral nerves through the posterior femoral cutaneous (small sciatic), a branch of the sacral plexus.
The front of the thigh is supplied by the first, second, and third lumbar nerves, and, according to Head, there are five cutaneous areas. The lateral area receives twigs of the second and third lumbar nerves through the lateral (external) cutaneous nerves. There are two medial areas, an upper and a lower. The former is supplied by the lumbo-tnguinal (crural) branch of the genito-femoral (genito- crural), which conveys twigs of the first and second lumbar nerves; the latter receives fibres of the second and third lumbar nerves through one of the an-
terior (middle) cutaneous branches of the femoral (anterior crural) nerve. The small upper and medial area is supplied by the first lumbar nerve through the iUo-inguinal, and the lower medial area receives twigs of the second and third lumbar nerves through one of the anterior cutaneous branches (internal cutaneous) of the femoral (anterior crural) nerve (fig. 776).
Of the skin over the region of the popliteal space, the medial portion receives fibres from the second, third, and fourth lumbar nerves through the anterior (internal) cutaneous branch of the femoral (anterior crural) nerve and through the superficial division of the obturator nerve; the middle and lateral portion receives twigs of the first three sacral nerves through the posterior cutaneous (small sciatic) nerve (fig. 776).
The skin over the front and medial side of the leg is supplied by the fourth lumbar nerve through the saphenous nerve, and the skin of the front and lateral side receives nerve-fibres from the fifth lumbar nerves through the sural cutaneous (fibular communicating) branch of the common peroneal (external popliteal) nerve.
In the skin of the back of the leg four areas can be distinguished, a medial, two middle, upper and lower, and a lateral area. The medial area is supphed by the fourth lumbar nerves through an anterior cutaneous branch (internal cutaneous) of the femoral (anterior crural)
nerve and the superficial branch of the obturator nerve. The upper middle area is supplied by the second, and third sacral nerves through the posterior femoral cutaneous (small sciatic) nerve, and the lower middle area by the first sacral nerve through the sural (external saphenous) nerve. The lateral area is supphed by the fifth lumbar nerve through the lateral sural cutaneous (fibular communicating) branch of the common peroneal (external popliteal) nerve (fig. 776, 780, 781).
The skin of the dorsum of the foot is supplied principally by the fifth lumbar and by the first sacral nerves," the majority of the nerve-fibres travel by the superficial peroneal (musculocutaneous) nerve, but the adjacent sides of the first and second toes are supplied by the femoral (anterior crural) nerve and the side of the dorsum of the httle toe is supplied through the sural (external saphenous).
The skin of the region of the heel is supplied by the first sacral nerve, the medial surface and medial part of the under surface by the medial calcaneal branches of the tibial (calcaneoplantar) nerve and the posterior, external, and lower aspects by the sural (external saphenous) nerve (fig. 776).
The sole of the foot in front of the heel receives cutaneous fibres from the fifth lumbar and the first sacral nerves; the medial area, which includes the medial three and a half digits, being supplied by the medial plantar nerve which conveys fibres of the fifth lumbar and the first sacral nerves; and the lateral area by the fifth lumbar nerve through the lateral plantar nerve.
The skin of the scrotum and penis is supphed by the first lumbar nerve through the ihoinguinal nerves, and by the second and third sacral nerves through the perineal and dorsal penile branches of the pudendal (pudic) nerve.
The cutaneous areas of the lower extremity which have been demarcated by Head and Thorburn are shown in fig. 780. These do not conform wholly with each other nor with the areas given in more detail in fig. 776, due probably to individual differences in subject and observer and to the difficulties coincident with the overlapping of the areas. Fig. 781 is more general in character and is considered more approximately correct.
The homology of the parts of the plexuses of the upper and lower extremities is not well carried out in the distribution of the nerves. The radial and great sciatic nerves are similar to the extent that the one arises from the posterior cord of the brachial plexus and the other from the sacral ple.xus, and that the one is distributed to the dorsal aspect of the arm and the other to the dorsal surface of the lower extremity, but the great sciatic supplies the sole of the foot, and the plantar muscles, whereas the radial does not supply the palm of the hand and the palmar muscles.
system which is especially concerned in the distribution of impulses to the
Fig. 782. — Diagram showing two stages of the Migration op the Primitive Ganglia PROM THE Ganglion Crest; A. the Division of the Primitive Ganglia into Spinal AND Sympathetic Portions, and B. the Formation op the Nerves.
Fig. 783. — Diagram Showing the Chief Paths of Migration op the Cells from THE Ganglia of the Spinal and Cranial Nerves to form the Adult Sympathetic System (After Schwalbe, modified.)
abundant in and largely comprise the viscera or splanchnic organs of the body, the largest and most evident of the structures comprising the sympathetic system are found either in or near the cavities containing the viscera. However, the
Fig. 784. — Scheme showing General Plan of the Coarser Portions op the Sympathetic Nervous System and its Principal Communications with the Cbrebro-spinal System. (After Flower, modified.)
finer divisions of the system ramify throughout the whole body, supplying vasomotor fibres to the blood-vessels throughout their course, controlling the glands of the skin, and supplying pilo-motor fibres for the hairs, forming intrinsic plexuses within the walls of the viscera, and it is claimed that a few of its neurones
convey inpulses toward the central system (sensory sympathetic neurones). While it is very probable that certain of the simpler reflexes of the splanchnic organs may be mediated by the sympathetic system alone, yet the sympathetic is by no means independent of the cranio-spinal system, but is rather, both anatomically and functionally merely a part of one continuous whole. Throughout, it shares its domain of termination with cranio-spinal fibres, chiefly of the sensory variety, and most of its rami and terminal branches carry a few cranio-spinal fibres toward their areas of distribution. Likewise the cranio-spina,l nerves carry numerous sympathetic fibres gained by way of rami connecting the two systems.
Like the cranio-spinal system, the sympathetic consists of cell-bodies, each of which gives off one axone. In addition, the cell-bodies give off numerous dichotomously branched dendrites by which their receptive surfaces are increased, and they are accumulated into ganglia, large and small. The larger ganglia have more or less constant positions, shapes, and arrangements, while the smaller, some of which are microscopic, are scattered throughout the body in a seemingly more indefinite manner. The axones or fibres arising in these gangha are given off in trunks and rami which associate the ganglia with each other or with the cranio-spinal system, or which pass from the ganglia to be distributed directly upon their allotted elements.
The sympathetic fibres arising from the ganglia are, for the most part, either totally nonmedullated or partially medullated. Some fibres are completely medullated near their cells of origin, but lose their meduUary sheaths before reaching their terminations. Some of them possess complete medullary sheaths throughout, but in no cases are the sheaths as thick or well developed as is the rule with the cranio-spinal fibres. Thus, nerve-trunks and rami in which sympathetic fibres predominate appear greyish in colour and more indefinite, as distinguished from those of the cranio-spinal nerves, which always appear a glistening white, due to hght being reflected from the emulsified myelin of the sheaths of their fibres.
Origin of the S3rmpathetic system. — Not only must the cranio-spinal and sympathetic systems be considered anatomically continuous and dependent, but ako the neurones of the two systems have a common origin, namely, the ectoderm of the dorsal mid-line of the embryo. The cells of the ganglion crest (see p. 754) become arranged in segmental groups and soon separate into two varieties: — those which will remain near the spinal cord and develop into the spinal ganglia, and those which, during the growth processes, migrate and become displaced further into the periphery and form the sympathetic gangha.
Sympathetic ganglion 1 Gangliated ^ Sympathetic trunk / trunk ' Sympathetic cell body in spinal ganglion
In the development of the sympathetic system the migration from the vicinity of the central system occurs to varying extents, so that in the adult the cells comprise three general groups of ganglia situated different distances away from the central nerve axis. — (1) A large portion of the cells remain near the central system and form a linear series of ganglia which, with the trunks connecting them, become two gangliated nerve trunks extending along each side, proximal to and parallel with the vertebral column; (2) a still larger portion of the cells migrate further toward the periphery and are accumulated into ganglia which assume an intermediate position and which, with the rami associating them with each other and with other structures, form a series of great prevertebral
plexuses; (3) still other cells wander even further away from the locality of their origin and invade the very walls of the organs innervated by the sympathetic system. The latter cells occur as numerous small terminal ganglia, most of which are microscopic and which, with the twigs connecting them, form the most peripheral of the sympathetic plexuses. Examples of these are the intrinsic ganglia of the heart and pancreas and the plexuses of Auerbach and Meissner in the walls of the digestive canal. Small, straggling ganglia may be found scattered between these three general groups. In the head, the gangliated trunks and great prevertebral plexuses are represented by the ciliary, sphenopalatine, otic and submaxillary ganglia and the plexuses associated with these. The supporting tissue of the sympathetic system accumulates early and is probably all of mesodermic origin.
Construction of the sympathetic system. — The sympathetic ganglia may be considered as relays in the pathways for the transmission of impulses from the region in which they arise to the tissues in which they are distributed; the cells composing the ganglia are the cell-bodies of the neurones interposed in the various neurone chains performing this function. A fibre arising from a cell-body in a given ganglion may pass out of the ganglion and proceed directly to its termination upon a smooth muscle-fibre or gland-cell, or it may pass through a connecting trunk to another ganglion and there terminate about and thus transmit the impulse to another cell, which, in its turn, may give off the fibre which bears the impulse to the appropriate tissue-element. Fibres arising in given ganglia may pass uninterrupted through other ganglia and proceed to their respective destinations. On the other hand, several neurones may be involved in the transmission of a given impulse when sent from a region distant from the tissue to which it is distributed.
Communication between the central nervous system and the sympathetic is established through both efferent and afferent fibres. In the region of the spinal cord both varieties of fibres pass from one system to the other by way of the rami communicantes, delicate bundles of fibres connecting the nearby sympathetic trunk with the respective spinal nerves (fig. 785).
The efferent fibres of the rami arise in the ventral horn (dorso-lateral cell-group chiefly) of the spinal cord, emerge through the ventral roots, enter the rami, and terminate chiefly about the cells of the nearest sympathetic ganglion; some, however, may pass through or over the ganglion of the sympathetic cord and terminate about cells in more distant ganglia. Since these fibres transmit impulses from the central to the sympathetic system, they are known as visceral efferent fibres. They are of smaller size than is the average for the cranio-spinal efferent or motor fibres of the ventral root. The visceral afferent fibres are of two varieties: — (1) Peripheral processes of the spinal ganglion-cells which run outward in the nerve-trunk, enter the rami communicantes, pass through the various connecting trunks and terminal rami of the sympathetic and terminate in the tissues supplied by these rami. . Such are merely sensory fibres of the cranio-spinal type which collect impulses in the domain of the sympathetic and convey them to the central system by way of the sympathetic nerves and the dorsal roots of the spinal nerves. (2) Afferent sympathetic fibres proper. The actual existence of these has not been long established, and their relative abundance is as yet uncertain. They consist of fibres arising in the sympathetic ganglia which enter the spinal ganglia by way of the rami commnicantes and the cranio-spinal nerve-trunk and terminate in arborisations about the spinal ganglion-cells (fig. 785). The afferent impulses transmitted by these sympathetic fibres are borne into the spinal cord or brain by way of the cranio-spinal fibres of the dorsal roots. These sensory sympathetic fibres must necessarily either receive the impulses they bear from sympathetic neurones having both peripheral and central processes or they themselves must be axones or central processes of neurones having also processes terminating in the peripheral tissues. Doubtless the variety of visceral afferent fibres first mentioned greatly predominates.
The thoracic and the lumbar spinal nerves are connected with the sympathetic trunk (gangliated cord) by two rami communicantes. Most of both the visceral efferent and also the visceral afferent fibres (which arise in the spinal ganglia) pass by way of a separate ramus. Both these varieties being of the cranio-spinal type, and, therefore, medullated, they give the ramus a white appearance meriting the name white ramus communicans. Fibres of the sympathetic type predominate in the second ramus and thus it is the grey ramus communicans. The latter consists of: — (1) afferent sympathetic fibres and (2) of sympathetic fibres which join the primary divisions of the spinal nerves and course in them to their allotted tissues (fig. 785).
especially true for the fibres passing from the second, third, and fourth sacral nerves. In the cervical region white rami are not in evidence, a fact probably exphcable as due to an arrangement by which at least most of the visceral efferent fibres arising in the cervical segments of the spinal cord pass downward in these segments and join the sympathetic tlirough the white rami of the upper thoracic nerves; others may enter the cervical portion of the gangliated cord through the spinal accessory or eleventh cranial nerve, rather than through individual white rami, while others pass into the nerves of the brachial plexus to terminate in the minute ganglia of the plexuses upon the blood-vessels of the limb. All the spinal nerves are joined by grey rami communicantes from the sympathetic trunk.
Vaso-motor fibres to the meninges and intrinsic blood-vessels of the spinal cord pass to the spinal nerves by way of the grey rami. Thence they may reach the meninges by one of three ways: — (1) through the delicate recurrent or meningeal branch of the spinal nerve (fig. 785) ; (2) through the trunk and ventral
Corresponding communications exist between the cranial nerves and the sympathetic, but the corresponding rami usually extend further toward the periphery and in not so regular a manner as the communications between the spinal nerves and the sympathetic system. The mesencephalon, for example, is chiefly connected with the ciUary ganglion of the sympathetic by_ fibres which are sent through the oculo-motor nerve and which enter this ganghon by way of its short root and terminate about its cells. Visceral efferent fibres from the rhombencephalon pass outward to the sympathetic in the roots of the facial, glosso-palatine, glosso-pharyngeal.
vagus, and spinal accessory nerves, all of which have more or less irregularly disposed communicating rami. The ganglia of origin of the vagus, more than perhaps any other nerve, both receive impulses from visceral efferent fibres and give origin to sympathetic fibres. Likewise twigs of other cranial nerves, especially of the trigeminus, connect with (pass through) the small sympathetic ganglia of the head. The meningeal branches given by certain of the cranial nerves contain vaso-motor fibres, and these correspond to the sympathetic fibres in the recurrent branches and in the roots of the spinal nerves.
It is known that spinal ganglia and certain of the ganglia of the cranial nerves contain cell-bodies of sympathetic neurones — cell-bodies which, during the period of the migration peripheralward, remained within the confines of these ganglia (fig. 785). These cell bodies receive efferent impulses from ventral root fibres and send their axones further into the periphery just as if in the sympathetic ganglion. Their relative abundance is not known. It is supposed that the ganglia of the vagus, glosso-pharyngeus, trigeminus and the geniculate ganglion contain a considerable proportion of such sympathetic cell-bodies.
From the above it may be seen that the ganglia and connecting trunks and rami of the sympathetic system may be divided as follows: — (1) The two sympathetic gangliated trunks lying proximal to and parallel with the vertebral column; (2) the great prevertebral plexuses, of which there are roughly four, one in the head, one in the thorax, one in the abdomen, and one in the pelvic cavity (fig. 784), each of which is subdivided; (3) the numerous terminal ganglia and plexuses situated either within or close to the walls of the various organs; (4) the trunks and rami associating the ganglia with each other and thus contributing to the plexuses, or connecting the ganglia with other nerves or with the organs with whose innervation they are concerned. The trunks and rami may be divided into — (a) the rami communicantes, or central branches, connecting the sympathetic with the cranio-spinal and central systems; (Ja) associative trunks, best considered as those which associate sympathetic ganglia situated on the same side of the body; (c) commissural branches, or those which associate ganglia situated on opposite sides of the mid-line of the body, such as the transverse connecting branches between the sympathetic trunk in the lumbo-sacral region (fig. 787) , or all the associating trunks between the ganglia of plexuses occupying the mid-region of the body; {d) terminal or peripheral branches, or those which pass from the ganglia to their final distribution apparently uninterrupted by other ganglia.
THE SYMPATHETIC TRUNKS
The sympathetic gangliated trunks, or gangliated cords, of the sympathetic system are two symmetrical trunks with ganglia interposed in them at intervals of varying regularity, and extending vertically, one on each side of the ventral aspect of the vertebral column, from the second cervical vertebra to the first piece of the coccyx. Upon the coccyx the two trunks unite and terminate in a single medial ganglion, the ganglion coccygeum impar. The various ganglia are connected with the cranio-spinal nerves by the rami communicantes. Morphologically, each trunk might be expected to possess thirty-one ganglia, one for each spinal nerve, but, owing to the fusion of adjacent ganglia in certain regions, especially in the cervical, there are in the adult only twenty-one or twenty-two ganglia in each trunk. These occur as three cervical ganglia, ten or eleven thoracic ganglia, four lumbar and four sacral ganglia, and the ganglia n coccygeum impar, which is common to both trunks.
In the cervical region the sympathetic trunks lie in front of the transverse processes of the vertebra3, from which they are separated by the longus capitis (rectus capitis anticus major) and longus colli; in the thoracic region they he at the sides of the bodies of the vertebrae and on the heads of the ribs; in the lumbar region they are placed more ventraUy with reference to the spinal nerves and more in front of the bodies of the vertebrte and along the anterior borders of the psoas muscles; in the pelvis the ganglia lie between and ventral to the openings of the sacral foramina. In the lower lumbar and sacral region one gangUon may send rami communicantes to two spinal nerves and one spinal nerve may be connected with two gangha. The ganglia of the trunks throughout give off associative branches to the gangha of the prevertebral plexuses and branches to the nearby viscera and blood-vessels. These branches may appear either white or grey according to the predominance of meduUated or non-medullated fibres in them. In the lumbo-sacral region commissural or transverse branches between the gangha of the two trunks are especially abundant. In trunks having a whiter appearance, the greater part of the meduUated fibres producing it are sensory and visceral motor fibres from the spinal nerves which have passed through the sympathetic ganglia without termination. The nerve trunks connecting the ganglia of the sympathetic trunks all contain three varieties of fibres: — (1)
visceral motor fibres which have entered them in the white rami communicantes from the spinal nerves of higher or lower levels, and which are coursing in them to terminate in other gangUa, either in the trunks above or below or in ganglia not belonging to the trunks; (2) fibres arising in sympathetic ganglia of a higher or lower level and passing upward or downward to terminate in other ganglia of the trunk or to issue from the trunk and proceed to more peripheral ganglia or to ganglia of the opposite trunk (both associative and commissural fibres); (3) afferent fibres or sensory fibres arising either in the spinal ganglia, or sensory sympathetic fibres arising in sympathetic ganglia and coursing in the trunk to pass into spinal ganglia above or below by way of the grey rami communicantes.
The cephalic portion of the sympathetic system consists of numerous small ganglia and of numerous plexuses connected with the internal carotid nerve, the ascending branch given off by the superior cervical sympathetic ganglion. The cephalic ganglia are all relatively small. There are four considered in the ordinary macroscopic dissections, namely, the ciliary or ophthalmic, the sphenopalatine or Meckel's ganglion, the otic, and the submaxillary. To these may be added a portion of the superior cervical sympathetic ganglion, the sympathetic portions of the nodosal, petrous, geniculate and semilunar ganglia, and the various small ganglia dispersed in the plexuses.
It arises from the upper end of the superior cervical ganglion and passes through the carotid canal into the cranial cavity. It divides into two branches which subdivide to form a coarse plexus, the internal carotid plexus, which partly surrounds the internal carotid artery before the latter enters the cavernous sinus (fig. 787 and 788). It passes with the artery to the cavernous sinus, where it forms the finer meshed cavernous plexus.
The internal carotid plexus supplies offsets to the artery and receives branches from the tympanic plexus through the inferior carotico-tympanic nerve and from the spheno-palatine ganglion through the great deep petrosal nerve. It also communicates by fine branches with the semilunar (Gasserian) ganglion and with the abducens nerve.
The cavernous plexus gives branches of communication to the oculo-motor and trochlear nerves and to the opthalmic division of the trigeminus. According to Toldt and Spalteholz, it communicates with the tympanic plexus through the superior carotico-tympanic (small deep petrosal) nerve. It also communicates with the ciliary ganglion through the long root of the ciliary ganglion and usually through a separate sympathetic root of this ganglion. These branches may pass through the superior orbital (sphenoidal) fissure either separately or with the nasociliary (nasal) nerve.
mater on the sphenoid bone.
The terminal branches of the cavernous plexus consist of delicate filaments that anastomose freely, forming fine plexuses, and pass from the cavernous plexus along the terminal divisions of the internal carotid artery and their branches. These fine plexuses take the name of the artery on which they lie. The four larger of them are the plexuses of the anterior and middle cerebral arteries, the plexus of the chorioid artery, and the ophthalmic plexus.
The cervical portion of the sympathetic cord extends upward along the great vessels of the neck. No white rami communicantes connect it directly with the spinal cord, but instead it receives visceral efferent fibres from the upper thoracic spinal nerves through the sympathetic trunk, and probably also from the cervical spinal cord through the spinal acessory nerve and the connections with the vagus. It sends grey rami communicantes to each of the cervical nerves. It extends from the subclavian artery to the base of the skull, lying dorsal to the sheath of the great vessels and in front of the longus capitis and longus colli, which separate is from the transverse processes of the cervical vertebrae (fig. 787). It usually
Fig. 787. — Showing the Sympathetic Trunks in their Relation to the Vertebral Column, to the Spinal Nerves, and to each Other. (Modified from^Toldt, "Atlas of Human Anatomy," Rebman, London and New York.)
The superior cervical ganglion is usually fusiform in shape and is sometimes marked by one or more constrictions. There is ground for the belief that it is formed by the coalescence of four ganglia corresponding to the first four cervical nerves. It varies from an inch to one and one-half inches (2.5 to 3.7 cm.) in length, lying dorsal to the upper part of the sheath of the great vessels of the neck and in front of the transverse processes of the second and third cervical vertebrae.
Fig. 788. — Diagram op the Glosso-palatine Nerve and the Relations op the GangliATED Cephalic Plexus to other Cranial Nerves. (After Bean.) Broken lines, motor; continuous lines, sympathetic; glosso-palatine .in solid black. Medial view. Left side.
It occasionally extends upward as high as the transverse process of the first vertebra (fig. 787). It is connected with the middle cervical ganglion by the intervening trunk, and it gives off a large number of communicating branches. Rarely, the ganglion may be double or split with a ventral portion lying superficial to the carotid sheath and a dorsal portion dorsal to the sheath, connected by sympathetic filaments near the superior and inferior extremities of the ganglion.
(2) Communicating branches to the cranial nerves. — An iiTegular number of small twigs pass between the superior cervical gangUon and the hypoglossal nerve and to the ganghon nodosum of the vagus. A named branch, the jugular nerve, runs upward to the base of the skull and divides into two branches, one of which enters the jugular foramen and terminates in the jugular ganghon of the vagus, and the other ends in the petrous ganghon of the glossopharyngeus. (See fig. 788).
(3) Four or five laryngo -pharyngeal branches come from the superior ganglion and the plexus extending downward from it, and pass forward and medialward, lateral to the carotid vessels, to the wall of the pharynx, where they unite on the middle constrictor with the pharyngeal branches of the glosso-pharyngeus and vagus, forming with them the pharyngeal plexus, from which branches are distributed to the walls of the pharynx and to the superior and external laryngeal nerves (fig. 787).
(4) The superior cervical cardiac nerve springs from the lower part of the ganglion or from the trunk immediately below it. It passes downward behind the carotid sheath, either in front of or dorsal to the inferior thyreoid artery, and in front of the longus colli, and establishes communications with the upper cervical cardiac branch of the vagus, the middle cervical cardiac branch of the sympathetic, and with the inferior and external laryngeal nerves. At the root of the neck the nerve of the right side passes in front of or behind the first part of the right subclavian artery, and is continued along the innominate artery to the front of the bifurcation of the trachea, where it ends in the deep part of the cardiac plexus. The left nerve passes into the thorax along the front of the left common carotid artery, crosses the front of the arch of the aorta immediately anterior to the vagus, and terminates in the superficial part of the cardiac plexus (fig. 789). Filaments from both the right and left nerves pass to the inferior thyreoid plexus.
(5) The external carotid nerves (fig. 787) pass forward from the .superior cervical ganglion to the external carotid arlcry, where they divide into branches which anastomose freely to form around the artery the external carotid plexus. This plexus extends to the beginning of the artery, and is continued upon the common carotid artery as the common carotid plexus. From the external carotid plexus, filaments pass to form secondary plexuses around each of the branches of the external carotid artery. These plexuses take the names of the arteries which they follow, namely, the superior thyreoid plexus, lingual plexus, etc. Filaments pass from the external carotid plexus to the glomus caroticum (the carotid gland), and from the superior thyreoid plexus to the thyreoid gland.
glion.
A part of the internal maxillary plexus is continued upon the middle meningeal artery as the meningeal plexus. From this plexus filaments pass to the otic ganglion, and sometimes a branch, called by English anatomists the external superficial petrossal nerve, passes to the geniculate ganglion.
2. The Middle Cervical Ganglion
The middle cervical ganglion is small and somewhat triangular in outline. It is sometimes absent. Its position is variable, but it commonly lies about the level of the cricoid cartilage, in front of the bend of the inferior thyreoid artery (fig. 787), and it is associated with the superior cervical ganglion and with the inferior cervical ganglion by the trunk of the gangliated cord. From the lower part of the middle ganglion some filaments pass dorsal to the subclavian artery, while others pass in front of and beneath that artery and anastomose with the first-mentioned filaments to form a loop, the ansa subclavia {ansa Vieussenii) (figs. 751, 787). Filaments from this loop to the inferior cervical ganglion thus form another communication between the middle and inferior cervical ganglia.
(c) One or more peripheral branches pass along the inferior thyreoid artery and anastomose with branches from the superior and middle cardiac nerves and from the inferior cervical ganghon, thus taking part in the formation of the inferior thyreoid plexus, from which branches pass to the thyreoid gland.
{d) The middle cardiac nerve arises by one or more branches from the ganghon, or from the trunk of the cord, and passes downward dorsal to the common carotid artery and, on the right side, either in front of or dorsal to the subclavian artery, and then along the innominate artery to the deep part of the cardiac plexus (figs. 787 and 789). It is frequently larger than the superior cardiac nerve. On the left side the nerve runs between the subclavian and common carotid arteries. On both sides the nerve communicates with the inferior laryngeal nerve and external laryngeal nerve.
The inferior cervical ganglion is irregular in form. It is larger than the middle cervical ganglion, and it lies deeply in the root of the neck dorsal to the vertebral artery or the first part of the subclavian artery, and ventral to the interval between the transverse processes of the last cervical and the first thoracic vertebrse (figs. 759, 761). It is connected with the middle cervical ganglion by
the sympathetic trunk, and by filaments passing to the ansa subclavia (Vieussenii), and it is either blended directly with the first thoracic ganglion or connected with it by a short stout portion of the trunk. It gives rami to the last two cervical nerves and peripheral branches to the vertebral and internal mammary arteries, to the heart, and to the inferior thyreoid plexus.
(2) The branches to the vertebral artery are large and they unite with similar branches from the first thoracic ganglion to form a plexus, the vertebral plexus (fig. 787), which accompanies the artery into the posterior fossa of the cranium, where it is continued on the basilar artery. The plexus communicates in the neck by delicate threads with the cervical spinal nerves. These are probably meningeal rami.
(4) The inferior cardiac nerve may arise from the inferior cervical ganglion, from the first thoracic ganglion, or by filaments from both these ganglia (figs. 787 and 789). It communicates with the recurrent laryngeal nerve and with the middle cardiac nerve, and passes to the deep part of the cardiac plexus. On the left side it frequently joins the middle cardiac nerve to form a common trunk.
Construction of the cervical portion of the sympathetic trunk. — This portion of the trunk contains both meduUated and non-medullated fibres, and a large part of the former are of cranio-spinal origin. In the absence of white rami communicantes to this portion of the sympathetic trunk, it is evident that few if any of the cranio-spinal or efferent visceral fibres are contributed to it below the superior ganglion by the cervical region of the spinal cord. Instead, such fibres are known to enter by way of the white rami from the upper thoracic nerves, and to ascend to this portion of the sympathetic trunk. Most of these fibres terminate about the cells of the superior, middle, and inferior cervical ganglia, and these cells in their turn give off sympathetic fibres which pass by way of the branches mentioned above for the cephalic and cervical portions, to their distribution in the structures of the head, neck, and thorax. The efferent visceral fibres which terminate in the superior ganghon especially are among those which mediate — (1) vaso-motor impulses for the head; (2) secretory impulses for the submaxillary gland; (3) pilo-motor impulses for the hairs of the face and neck; (4) motor impulses for the smooth muscle of the eyelids and orbit, and (5) dilator impulses for the pupil. The sympathetic or grey fibres in the cervical portion of the sympathetic trunk arise from the cells of the upper thoracic and the cervical ganglia, and are passing either to connect the ganglia with each other or to enter the peripheral branches and proceed to their terminal distribution.
THE THORACIC PORTION OF THE SYMPATHETIC TRUNK
The thoracic part of the gangliated trunk runs downward on the heads of the ribs from the first to the tenth, and then passes a little ventralward on the sides of the bodies of the lower two thoracic vertebrse. Above it is continuous with the cervical portion at the root of the neck, dorsal to the vertebral artery. Below it leaves the thorax dorsal to the medial lumbo-costal arch (arcuate ligament), or sometimes dorsal to the lateral lumbo-costal arch, and continues into the lumbar portion of the trunk. It lies behind the costal pleura and crosses over the aortic intercostal arteries.
The number of ganglia in this part of the trunk is variable. There are usually ten or eleven, but the first is sometimes fused with the inferior cervical ganglion and occasionally other ganglia fuse. The ganglia are irregularly angular or fusiform in shape, and lie on the head of the ribs, on the costo-vertebral articulations, or on the bodies of the vertebrae. The portions of the trunk connecting the ganglia usually are single, but sometimes they are composed of two or three small cords in juxtaposition. Each ganglion, with the possible exception of the first, receives a white ramus comnmnicans from a thoracic nerve and all give off grey rami communicantes to these nerves.
The white rami communicantes, as they approach the sympathetic trunk, quite often appear double, due to the separation of a large portion of their fibres into two main streams, one passing upward in the sympathetic trunk, and one passing downward. Of the white rami from the upper five thoracic nerves, the upward stream of fibres is much larger than the downward, due to the fact that a greater part of the efferent visceral fibers from these nerves are distributed through the cervical portion of the sympathetic trunk, as noted above in the construction of that portion. Usually the white rami from the spinal nerves pass directly to the corresponding ganglia of the trunk, and thus lie in company with the corresponding grey rami. Sometimes, however, they may join the intermediate portions of the trunk, and in the lower thoracic region especially, a ramus may pass from a nerve to the ganglion corresponding to the nerve above or below. The
fibres of the white rami from the lower thoracic nerves are in greater part directed downward in the sympathetic trunk, and also downward in its peripheral branches, to be distributed to the abdominal viscera. In all cases, however, some of the fibres of the thoracic white rami terminate in the ganglia nearest their junction with the trunk, while others pass into the nearest peripheral branches. In this way the white rami from all the thoracic spinal nerves, especially those of the mid-region, are directly concerned in the innervation of the thoracic viscera, lungs, oesophagus, aorta, etc.
The first thoracic ganglion is larger than the other ganglia of this region and is irregular in form. It may be narrowly ovoid or semilunar. It lies in front of the neck of the first rib, behind the pleura, and on the medial side of the costocervical trunk (superior intercostal artery), which vessel separates it from the prolongation of the portion of the first thoracic nerve which passes to the brachial plexus. It sometimes fuses with the inferior cervical ganglion, and, on the other hand, sometimes extends to the upper part of the second rib to fuse with the second thoracic ganglion. The result of the latter fusion resembles the stellate ganglion of the carnivora, and when it occurs, is sometimes referred to as the ganglion stellatimn. When well developed, the first ganglion sends a branch to the cardiac plexus, forming the fourth cardiac nerve of Valentin. ^
The second thoracic ganglion, triangular in shape and almost as large as the preceding, is sometimes placed on the costo-vertebral articulation, and is sometimes partly concealed by the first rib.
The central branches are the grey rami communicantes, which pass from the ganglia to the corresponding spinal nerves. After they have joined with the anterior primary divisions of the nerves, the fibres of these rami divide into four groups: — (1) Fibres which pass medialward along the roots of the nerves to supply vessels of the membranes of the spinal cord, or enter a meningeal or recurrent branch for the same purpose; (2) fibres which enter the spinal ganglion and terminate there (sensory sympathetic fibres) ; (3) fibres which pass dorsalward into the posterior primary divisions of the nerves; (4) fibres which pass lateralward in the anterior primary divisions of the nerves. The last two groups of fibres are distributed to the muscle of the blood-vessels of the body-walls, to the skin-glands, and to the muscles of the hairs of the body.
(2) Aortic branches, some of which arise directly from the gangha and some from the pulmonary branches, and unite with branches from the cardiac plexus and from the splanchnic nerves to surround the aorta as the thoracic aortic plexus (fig. 789). This plexus accompanies the aorta into the abdomen and there joins with the coehac (solar) plexus.
(4) Vertebral branches, some of which pass with the nutrient arteries into the bodies of the vertebra; and some of which pass to the median line and there anastomose with similar branches from the opposite side (commissural branches).
The peripheral ganglionic branches forming the lower series consist largely of efferent and afferent fibres from the spinal nerves, which pass through the gangha and reinforce the sympathetic filaments proper. Thus composed, these branches run ventralward and medialward on the sides of the bodies of the vertebrae and unite to form the splanchnic nerves which supply the abdominal organs, the afferent fibres serving to collect sensory impulses in this domain of the sympathetic.
ganglia (fig. 787). It is usually formed by branches from the fifth to the tenth. The superior branch, usually the largest, receives smaller inferior branches from the lower ganglia as it passes downward on the sides of the bodies of the vertebrae in the posterior mediastinum. The nerve enters the abdominal cavity bypassing through the crus of the diaphragm, and joins the upper end of the coeliac (semilunar) ganglion of the coeliac (solar) plexus. Near the disk between the eleventh and the twelfth thoracic vertebra there is formed on the nerve the splanchnic ganglion. Filaments from the nerve and from this ganglion pass along the intercostal arteries to the aorta, oesophagus, and the thoracic duct, and some fibres from the right side pass to the vena azygos (major). Sometimes this nerve divides into two cords, giving off numerous branches which anastomose with each other and with the lesser splanchnic nerve to form a plexus, in the meshes of which are found some small ganglia.
(2) The lesser splanchnic nerve receives fibres from the ninth and tenth gangha. Its course is similar to that of the great splanchnic nerve (fig. 787), but on a more dorsal plane, and it terminates in the cceliac (solar) and renal plexuses.
and ends in the renal plexus.
Construction of the thoracic portion of the cord. — The majority of the visceral efferent fibres which pass from the central nervous system enter the thoracic portion of the sympathetic trunk; some end there in ramifications around the cells of its ganglia, while others merely pass through on their way to more distant terminations. With regard to those which terminate in the gangha, it has been shown that in the dog and cat many end in the ganglion stellatum which corresponds with the last cervical and the upper three or four thoracic ganglia in man. Among these are the fibres conveying secretory impulses to the sweat-glands of the upper hmb, which emerge from the spinal cord in the thoracic nerves from the sixth to the ninth, and, in the dog, those which convey and transfer vaso-constrictor impulses to the sympathetic neurones supplying the pulmonary blood-vessels. These visceral efferent fibres leave the spinal cord in the second to the seventh thoracic nerves. Other fibres which terminate around the thoracic sympathetic ganglion-cells in the dog and cat are the vaso-constrictor fibres for the upper limbs and some of the vaso-constrictor fibres for the lower limbs.
Of the fibres which traverse the thoracic portion of the sympathetic trunk to gain more distant terminations, some ascend to the cervical region (p. 1033), others descend to the lumbar region, and many pass by the immediate peripheral branches to the splanchnic nerves.
Among those which descend to the lumbar region are pilo-motor fibres, vaso-motor fibres, and secretory fibres to the lower limb, some vaso-constrictor fibres to the abdominal bloodvessels, motor fibres to the circular, and inhibitory fibres to the longitudinal muscle of the rectum. The latter enter the sympathetic trunk by the lower thoracic nerves and pass in the lumbar peripheral branches to the aortic plexus, and terminate around the cells of the inferior mesenteric ganglion.
The visceral efferent fibres which pass through the thoracic ganglia to the splanchnic nerves are mainly vaso-motor fibres to the abdominal blood-vessels; the majority of them probably terminate around the cells of the ganglia in the coelio (solar) plexus, but those for the renal bloodvessels no doubt end in the renal ganglia. In addition to all the above-mentioned fibres there are in the thoracic part of the sympathetic trunk afferent fibres of both sympathetic and cerebro-spinal type, passing toward the spinal ganglia and the latter, greatly predominating, pass into the dorsal roots of the thoracic spinal nerves.
The lumbar portion of each trunk lies on the fronts of the bodies of the vertebrae along the anterior border of the psoas muscle, and nearer to the median line than the thoracic portion. It is connected with the thoracic portion of the sympathetic trunk by a slender intermediate portion of the trunk that may pass through the diaphragm or dorsal to it (fig. 787). The continuation of the lumbar into the sacral portion is also slender, and descends dorsal to the common iliac artery. The right trunk is partly covered by the vena cava inferior and the left by the aorta.
are usually four. Rarely they are so fused as to form one continuous ganglion.
White rami communicantes pass to the ganglia from the first two or three lumbar nerves only. This portion of the sympathetic trunk also receives visceral efferent and afferent fibres which are derived from the white rami communicantes of the lower thoracic nerves and continue downward in the trunk.
Branches. — As in the thoracic region, the branches from the gangha are central and peripheral. The central are grey rami communicantes. There may be two branches to a nerve or one ramus may divide so as to join two adjacent spinal nerves. Sometimes a spinal nerve may receive as many as five grey rami from the sympathetic trunk.
The peripheral branches include; — (a) Branches passing to the aorta and taking part in the formation of the aortic plexus; (6) branches which descend in front of the common ihac artery to the hypogastric plexus; and (c) branches to the vertebrse and ligaments.
The sacral part of each truak passes downward in front of the sacrum, immediately lateral to the medial borders of the anterior sacral foramina. It is continuous above with the lumbar portion of the trunk, and below it anastomoses freely in front of the coccyx with the trunk of the other side to form a plexus in the terminus of which is the coccygeal ganglion {ganglion coccygeum impar) (fig. 787). Like the cervical and lower lumbar portions of the sympathetic trunk, the sacral part receives no white rami communicantes from the spinal nerves.
Construction of the lumbar and sacral portions of the gangliated trunk. — The ganglia of both these portions of the trunk are very variable in shape, size, position, and number. There are usually four gangha belonging to each portion, but sometimes as many as eight may be distinguished in the lumbar and at other times there may be as many as six in the sacral portion. In the majority of cases, especially in the sacral region, these masses of cells are so fused that their number is less than the number of the spinal nerves with which they are associated. As noted above, only the first two or three lumbar spinal nerves send white rami which enter these ganglia directly as such. However, visceral efferent fibres descend this entire stretch of the trunk, through both the lumbar and sacral portions, from the white rami of the lower thoracic and the upper lumbar nerves above. These fibres either terminate in the various gangha or pass uninterrupted to the more distant sympathetic cell-bodies which are concerned in impulses that are vaso-motor to the genital organs, motor for the uterus, the vas deferens, and the muscular coats (circular coat especially) of the bladder. Also, some of them convey secretory, pilomotor, and vaso-motor impulses for the glands, skin, and vessels of the lower extremity in addition to the similar impulses conveyed in the peripheral branches from the lower part of the thoracic portion of the sympathetic trunk. The motor impulses for the uterus or vas deferens and for the bladder pass, in most part probably, by way of the peripheral branches from the lumbar portion of the cord, through the aortic plexus to the inferior mesenteric ganglion; others, the vaso-motor impulses to the genital organs especially, pass by way of the sacral ganglia and the peripheral branches from them to the hypogastric or pelvic plexus and the appropriate subplexuses of this region. Of the vaso-motor fibres for the penis, some of the constrictor fibres pass down the sacral portion of the sympathetic trunk and terminate about the cells of the sacral ganglia, and these cells send out sympathetic fibres which join and course in the pudic nerve (n. pudendus).
All of both the lumbar and sacral spinal nerves receive grey rami from the gangliated trunk. These, just as those from the other portions of the trunk, consist of — (1) vaso-motor fibres to vessels of the meninges and the vertebral canal; (2) sympathetic fibres which join the divisions of the spinal nerves and course in them to their distribution, and (3) afferent sympathetic fibres terminating in the spinal ganglia.
In addition to the visceral efferent fibres, the branches of the lumbo-sacral portion of the sympathetic trunk carry cerebro-spinal fibres of general sensibility — sensory fibres arising in the spinal gangha of this and the lower thoracic region.
There are no white rami proper passing from the sacral spinal nerves to course or terminate in the sympathetic trunk. Visceral efferent fibres are given off by these nerves in abundance, but, instead of entering the trunk and its ganglia, they form bundles which pass over the trunk and directly into its peripheral branches and to the more distant ganglia. The bundles passing from the second, third, and fourth sacral nerves are large and especially definite. While homologous to white rami, such bundles are better known as the visceral branches of the sacral nerves or the plevic splanchnics. They contain some spinal sensory fibres, but consist for the most part of visceral efferent, conveying impulses, vaso-motor (vaso-dilator, chiefly) to the genital organs, both motor and inhibitory for the rectum, uterus, and bladder (longitudinal coat especially), and secretory for the prostate gland. These fibres contribute to the hypogastric plexus and are interrupted in the small gangUa of its sub-plexuses, named according to the various urino-genital organs concerned.
THE GREAT PREVERTEBRAL PLEXUSES
The great prevertebral plexuses, in the body cavities, are three in number — the cardiac, the coeliac (solar or epigastric), and the hypogastric or pelvic. The cardiac plexus lies behind and below the arch of the aorta, and the coeliac and
THE CARDIAC PLEXUS 1041
hypogastric plexuses are situated in front of the lumbar vertebrae. Each plexus receives not only sympathetic fibres which have passed from or through the ganglia of the sympathetic trunks of either side, but also both afferent and efferent cranio-spinal nerve-fibres derived directly from the cranio-spinal nerves. In addition the cardiac and coeliac plexuses receive both efferent visceral and craniospinal sensory or afferent visceral fibres from both vagus nerves. It should be clearly understood that the branches which run from the sympathetic gangliated trunks to the prevertebral plexuses contain meduUated fibres which are passing, like the fibres from the sacral nei'ves, directly from the spinal cord to terminate about the cells of the plexuses.
The cardiac plexus is formed by the cardiac branches from both vagus nerves and from both sympathetic trunks. It lies beneath and dorsal to the arch of the aorta, in front of the bifurcation of the trachea, and extends a short distance upward on the sides of the trachea. It is composed of a superficial and a deep part (fig. 789).
The superficial part of the cardiac plexus is much smaller than the deep part, and lies beneath the arch of the aorta in front of the right pulmonary artery. It is formed chiefiy by the cardiac branches of the left vagus and by the left superior cardiac nerve, but sometimes receives filaments from the deep cardiac plexus. The cardiac ganglion (ganglion of Wrisberg,) usually found connected with this plexus, lies on the right side of the ligamentum arteriosum.
Branches. — From this plexus some branches pass to the left half of the deep cardiac plexus, and others accompany the left pulmonary artery to the left anterior pulmonary plexus. It also sends branches to the right anterior coronary plexus. ,
The deep portion of the cardiac plexus lies dorsal to the arch of the aorta at the sides of the lower part of the trachea and in front of its bifurcation. It consists of two lateral parts, more or less distinct, connected by numerous branches, which pass around the lower part of the trachea. It is formed by the superior, middle, and inferior cervical cardiac branches from the right sympathetic trunk, the middle and inferior cervical cardiac branches from the left trunk, and all the cervical and thoracic cardiac branches of the vagus except the superior cervical cardiac branch of the left vagus. It also receives branches from the superficial cardiac plexus.
The left part of the deep cardiac plexus gives branches to the left atrium (auricle) of the heart, to the left anterior pulmonary plexus, to the left coronary plexus, and sometimes to the superficial part of the cardiac plexus.
The right part of the deep cardiac plexus gives branches to the right atrium, to the right anterior pulmonary plexus, and to the right and the left coronary plexuses (fig. 789). The branches to the left coronary plexus pass behind the pulmonary artery. Some of those to the right coronary plexus pass anterior and some posterior to the right pulmonary artery.
They accompany the coronary arteries and are right and left.
The right {anterior) coronary -plexus receives filaments from the superficial part of the cardiac plexus, but is formed chiefiy by filaments from the right portion of the deep cardiac plexus (fig. 789). Its distribution to the heart follows that of the right coronary artery.
The left {posterior) coronary plexus is larger than the right plexus, and is formed for the most part by filaments from the left portion of the deep cardiac plexus, but it receives some filaments from the right portion of the deep cardiac plexus (fig. 789). Its distribution to the heart follows that of the left coronary artery.
The cardiac plexus and the network of nervous structures in the walls of the atria are the remains of the primitive plexuses found in the embryo, which are called the bulbarj the intermediate, and the atrial plexuses, terms which sufficiently indicate their relative positions. The bulbar plexus gives off the coronary nerves and is transformed into the superficial part of the deep cardiac plexus; the remainder of the deep cardiac plexus is formed by the intermediate plexus, and the atrial plexus becomes the network of the atrium.
are the so-called inhibitory, the latter motor. The inhibitory impulses leave the central nervous system by the spinal accessory and vagus nerves. The motor iibres leave the spinal cord by the ventral roots and white rami communicantes of the thoracic nerves and terminate about the cells of the intervening sympathetic ganglia. From the cells of these gangha arise the non-meduUated (grey) fibres of the plexus. These fibres terminate directly upon the fibres of cardiac muscle or about the cells of the minute intrinsic cardiac ganglia which in their turn give axones to the muscle.
The pulmonary plexuses are a continuation of the cardiac plexuses. The two are so intimately joined that it is difficult to distinguish them as separate plexuses. The pulmonary are formed by fibres from both the vagus and sympathetic nerves. The anterior and posterior pulmonary branches of the vagus unite, dorsal to the bifurcation of the trachea, with fibres from the second, third and fourth ganglia of the thoracic portion of the sympathetic trunk to form the anterior and posterior pulmonary plexuses that lie ventral and dorsal to the bifurcation of the trachea. Here the pulmonary plexuses of both sides connect with each other freely. Leaving the trachea, the plexuses pass into the lungs along the pulmonary arteries (figs. 744, 789) . The parts of the plexus of each side are named according to their position anterior or posterior to the right and left pulmonary arteries; thus, there is a right anterior and a right posterior, a left anterior and a left posterior pulmonary plexus.
The coeliac (solar or epigastric) plexus is the largest of the prevertebral plexuses. It is unpaired, and is continuous above with the aortic plexus of the thorax and below with the abdominal aortic and superior mesenteric plexuses. It lies in the epigastric region of the abdomen behind the bursa omentalis (lesser sac of the peritoneum) and the pancreas, upon the crura of the diaphragm and over the abdominal aorta, and around the origin of the coeliac and the superior mesenteric arteries. It occupies the interval between the suprarenal bodies and extends downward as far as the renal arteries. It is formed by the great and the lesser splanchnic nerves of both sides, by coeliac branches of the right vagus, and by filaments from the upper lumbar ganglia of the sympathetic trunlc. It sometimes receives coeliac branches from the left vagus. It contains two large ganglia, the right and left coeliac (semilunar) ganglia (fig. 790).
The coeliac (semilunar) ganglia are two large, flat, irregularly shaped masses, separable into a varying number of ganglia. These two masses, or rather the smaller ganglia which compose them, are associated by a varying number of communicating branches. Each mass, right and left, lies upon the corresponding crus of the diaphragm, at the medial border of the corresponding suprarenal body, being sometimes overlapped by this body. The right mass lies behind the inferior vena cava. Each coeliac ganglion receives at its upper border the greater splanchnic nerve, and, near its lower border, lying over the origin of the renal artery, is a more or less detached part, known as the aortico-renal ganglion. This ganglion receives the lesser splanchnic nerve and may seemingly give origin to the greater part of the renal plexus. Another part of the cceliac ganglion, often found dorsal to the origin of the superior mesenteric artery, is known as the superior mesenteric ganglion (fig. 790) .
From the coeliac plexus and its ganglia subordinate plexuses are continued upon the aorta and its branches. These comprise both paired and unpaired plexuses. The paired plexuses are the phrenic, suprarenal and renal, the spermatic in the male, and, in the female, the ovarian plexuses. The unpaired plexuses are the aortic, hepatic, splenic, superior gastric, inferior gastric, superior mesenteric, and inferior mesenteric.
That part of the coeliac plexus surrounding the coeliac artery was formerly described as the coeliac plexus. It is better considered as an unnamed part of the larger coeliac (solar) plexus. This part of the plexus receives fibres from both vagus nerves, and gives filaments that form plexuses around the branches of the cceliac artery and their ramifications.
consist of fibres from the upper part of the cceliac ganglia, which follow the inferior phrenic arteries and their branches on the under surface of the diaphragm (fig. 790). Filaments are given off by the roots of the plexuses to the suprarenal bodies, and others unite with the terminal branches of the phrenic nerves. The point of junction with the right phrenic nerve is marked by the phrenic ganglion, from which branches are distributed to the inferior vena cava, to the right suprarenal body, and to the hepatic plexus.
Fig, 790. — Abdominal Plexuses of the Sympathetic. (After Toldt, "Atlas of Human Anatomy," Rebman, London and New York.) Coeliac plexus Left vagus nerve
along the suprarenal arteries, from the phrenic plexus along the inferior phrenic arteries, and from the renal plexus along the inferior suprarenal arteries. They are distributed to thesubstance of the suprarenal bodies. Cell-bodies of sympathetic neurones are enclosed within the suprarenal bodies forming intrinsic ganglia. The medulla of the suprarenal is of ectodermal origin and considered as derived from undeveloped components of the sympathetic nervous system.
(3) The renal plexuses receive fibres from the lower part of the coeliac ganglia and from the coeliac and aortic plexuses. They also receive filaments from the least splanchnic nerves, when these nerves are present, and sometimes filaments from the small splanchnic nerves and from the first lumbar ganghon of the sympathetic trunk. These plexuses pass along the renal arteries into the substance of the kidneys. Most of the fibres of each renal plexus are grey fibres, and as they pass to the kidneys small renal ganglia are present upon them. Both renal plexuses give branches to the corresponding spermatic plexuses and to the ureter, and the right renal plexus gives filaments also to the inferior vena cava.
(4a) The spermatic plexuses (fig. 790) are formed by fibres from the renal and aortic plexuses. They accompany the spermatic arteries and are joined at the abdominal inguinal (internal abdominal) ring by fibres that have passed along the vas deferens from the pelvic plexuses. Their terminal filaments are distributed to the testis and the epididymis.
(4b) The ovarian plexuses are formed in the female like the spermatic plexuses in the male. They accompany the ovarian arteries and, in the broad ligament, receive fibres from the utero-vaginal plexus. They supply the ovaries, the broad ligaments, and the Fallopian tubes, and send some fibres to the fundus of the uterus, where they become continuous with the utero-vaginal plexus.
The unpaired subordinate plexuses: — (I) The abdominal aortic plexus is formed by two strands of fibres which descend along the sides of the aorta and communicate with each other across its ventral aspect. It is connected above with the renal plexuses, and it receives peripheral branches from some of the lumbar ganglia of the sympathetic trunk on each side. It often contains a number of ganglia, which are situated at the points where the peripheral branches join the plexus, and it terminates below, chiefly by anastomoses with the hypogastric plexus (figs. 790 and 791). Besides giving filaments to the inferior vena cava, it also gives fibres that form plexuses along each of the branches of the aorta. The fibres tnat pass from the lower end of the aortic plexus upon the common ihac artery form the iliac plexus, which is continued along the femoral artery as the femoral plexus, and still further along the popliteal artery as the popliteal plexus.
(2) The superior gastric (coronary) plexus, receiving filaments from the coeliac plexus, accompanies the left gastric (coronary) artery along the lesser curvature of the stomach. Its filaments anastomose with filaments of the vagus nerves and with the plexus that accompanies the right gastric (pyloric) artery (fig. 790), and it gives fibres to the walls of the stomach which terminate within the walls, about the cell bodies of the delicate gangliated plexus myentericus and plexus submucosus (plexuses of Auerbach and Meissner). The axones of these supply' the smooth muscle of the stomach walls and its vessels.
(.3) The inferior gastric plexus receives from the splenic plexus filaments that accompany the left gastro-epiploic artery. It gives filaments to the walls of the stomach, which terminate as in the superior gastric plexus, and it receives filaments from the vagus nerves and from the plexus that accompanies the right gastro-epiploic artery.
(4) The hepatic plexus receives filaments from the cceUac plexus and from the left vagus. It accompanies the hepatic artery and gives fibres that form plexuses on the branches of the artery and on their ramifications within the liver and gives secretory fibres to the liver cells. It also gives filaments to the portal vein (fig. 790).
The splenic or lienal plexus is formed by filaments from the coeliac plexus, the left cceliac (semilunar) ganglion, and from the right vagus. It accompanies the splenic artery and gives filaments which form plexuses on the branches of this artery, and which pass with the branches to supply fibres to the stomach and the pancreas (fig. 790).
(5) The superior mesenteric plexus is formed chiefly by filaments from the lower part of the coeliac plexus, but it also receives fibres from the right vagus and fibres direct from the coeliac (semilunar) gangUa. At the origin of this plexus, dorsal to the superior mesenteric artery, lies the superior mesenteric ganglion (fig. 790). The filaments of the plexus, which are white and firm, accompany the superior mesenteric artery and, following its branches and their ramifications, are distributed to the walls of the small intestine, the caecum, and the ascending and transverse colon. From the secondary plexuses that accompany the branches of the artery fibres pass to form still other plexuses that lie near the wall of the intestine, between the branches of the artery and between the layers of the mesentery. Filaments pass with the branches of the arteries and from plexuses between them into the intestinal wall, and there form between the longitudinal and circular muscle layers of the intestine the fine ganghated plexus myentericus (plexus of Auerbach), and filaments from this plexus form in the submucosa the deUcate plexus submucosus or plexus of Meissner. From these latter plexuses fibres arise which terminate upon the gland cells and smooth muscle fibres of the intestinal wall and its vessels. The white appearance of the filaments of the superior mesenteric plexus is due to the large number of cranio-spinal sensory and visceral motor fibres (vagus especially) in it.
(6) The inferior mesenteric plexus is derived chiefly from the left side of the aortic plexus. It descends upon the inferior mesenteric artery and gives off filaments which accompany the branches of the artery and are distributed to the descendiog colon and to the iho-pelvic colon (figs. 790 and 791). The filaments which accompany the left colic brunch of the inferior mesenteric artery anastomose with the filaments of the superior mesenteric plexus which accompany the middle coHc artery. The filaments which accompany the superior hasmorrhoidal artery form the superior hsemorrhoidal plexus. This plexus gives off the superior hcemorrhoidal nerves (fig. 791) which supply the upper part of the rectum and anastomose with the middle hcemorrhoidal plexus.
4. The Hypogastric Plexus
The hypogastric plexus Ues partly in the abdominal cavity and partly in the pelvic cavity. It is formed chiefly by filaments continued downward from the aortic plexus, and by the pelvic splanchnics and peripheral branches from the lumbo-sacral nerves and sympathetic trunk (fig. 784). The abdominal part of this plexus consists of plexiform bundles of fibres descending between the common iliac arteries and interlacing in front of the fifth lumbar vertebra to form a broad, flattened, plexiform mass. In its extent it receives branches from the lumbar ganglia of the sympathetic trunk. This plexiform mass then divides into two
authors, are frequently designated as the pelvic plexuses.
The pelvic parts of the hypogastric plexus (pelvic plexuses) lie at the sides of the rectum in the male, and at the sides of the rectum and the vagina in the female. They receive peripheral branches from the sacral ganglia of the sympathetic trunk and visceral efferent fibres by way of the pelvic splanchnics from the second and
Great cavernous nerve
third or third and fourth sacral spinal nerves. Each pelvic part of the plexus accompanies the corresponding hypogastric (internal ihac) artery, and gives off secondary plexuses that continue on the branches of the artery to the pelvic viscera. Of these secondary plexuses, the middle hsemorrhoidal and the vesical plexus are common to both sexes and are paired.
REFERENCES FOR NERVOUS SYSTEM 1047
The vesical plexus receives some branches from the pelvic parts of the hypogastric plexus, but is largely reinforced by way of the pelvic splanchnios, from the third and fourth sacral nerves. Each part passes along the corresponding vesical arteries to the bladder, and gives off two sets of branches, namely, the superior vesical nerves (fig. 791), which supply the upper part of the bladder-waU and send some branches to the ureter, and the inferior vesical nerves, which supply the lower part of the bladder and, in the male, give secondary deferential plexuses to the vas deferens. These plexuses surround the vasa deferentia and the vesiculse seminales and anastomose with the spermatic plexuses.
The prostatic plexus, found only in the male, is formed in two parts by nerves of considerable size, and lies chiefly on the sides of the prostate gland between it and the levator ani (fig. 791). Each of the.se parts supplies the gland and the prostatic part of the urethra^ and sends offsets to the neck of the bladder and the vesioute seminales.
The large cavernous nerve, one on each side, runs forward to the middle of the dorsum of the penis, where it anastomoses with the dorsal nerve of the penis on the corresponding side, and ends in twigs which are distributed chiefly to the walls of the sinuses of the corpus cavernosum penis, but some of the terminal filaments supply the corpus cavernosum urethrte (corpus spongiosum) (fig. 791).
cavernosum.
The utero-vaginal plexus, found in the female, is formed in its upper part on each side largely by fibres clerived from the pelvic part of the hypogastric plexus, but it receives some fibres from the pelvic splanchnics of the third and fourth sacral nerves. The nerves from this part of the plexus accompany the uterine arteries as they pass between the layers of the broad ligament. Some accompany each uterine artery and its branches to their termination, but a considerable number of fibres leave the artery and pass into the body of the uterus to supply its lower part and cervix. Between the layers of the broad ligament this plexus anastomoses with the ovarian plexus and sends some filaments to the uterine tube (Fallopian tube). The lower part of the plexus ulero-vaginalis receives some fibres on each side from the pelvic part of the hypogastric plexus, but it is formed chiefly by efferent visceral fibres from the second, third, and fourth sacral nerves. These fibres terminate in contact with intrinsic cell-bodies whose axones supply the wall and mucous membrane of the vagina and urethra. From the plexus on the anterior surface of the vagina fibres pass to form the cavernous plexus of the clitoris, which gives off the great and lesser cavernous nerves of the clitoris for the supply of the clitoris. The utero-vaginal plexus of the female corresponds to the prostatic plexus of the male.
References for the Nervous System. A. General. Barker, Nervous System, 1899; Edinger, Vorlesungen, 1908; Johnston, Nervous System, 1906; (phylogeny) Parker, Anat. Eec, vol. 4; {develo-pment) Streeter, in Keibel and Mall's Human Embryology. B. Brain and Spinal Cord. Bechterew, Funktionen der Nervencentra, 3 vols., 1908; {cell-structure) Malone, Anat. Rec, vol. 7; {axone-sheaths) Hardesty, Amer. Jom*. Anat., vol. 4; (cortical localization) Donaldson, Jour. Nerv. and Mental Dis., vol. 13; Smith, Jour. Anat. and Physiol., vol. 41; Israelsohn Ai'b. Wien. neurol. Inst., vol. 20; (central fissure) Symington and Crymble, Jour. Anat. and Physiol., vol. 47; (brain-weight) Pearl, Jour. Comp. Neurol., vol. 25; Spitzka, Phila. Med. Jour., 1903; (ventricles Harvey, Anat. Rec, vol. 4; (mid-brain and medulla) Sabin, Atlas, 1901; (trigeminal nuclei) Willems, Nevraxe, T. 12; (spinal cord, cornparative) BuUard, Amer. Jour. Anat., vol. 14. C. Peripheral. (Histogenesis) Bardeen, Amer. Jour. Anat., vol. 2; (experimental) Harrison, Amer. Jour. Anat., vol. 5; Jour. Exper. ZooL, vol. 9; (phylogeny of facial) Sheldon, Anat. Rec, vol. 3; (trigeminus) Symington, Jour. Anat. and Physiol., vol. 45; (nervus termnialis) Johnston, Anat. Rec, vol. 8. (afferent spinal neurones) Ranson, Jour. Comp. Neurol., vol. 18; (structure) Ranson, Anat. Rec, vol. 3; (brachial plexus) Todd, Anat. Anz., Bd. 42; (abdominal, statistical) Bardeen, Amer. Jour. Anat., vol. 1 (sympathetic terminations) Boeke, Anat. Anz., vol. 44.
GENERAL CONSIDERATIONS
THE term "special sense organs" indicates those structures situated on or near the surface of the body which receive the impressions of sound, light taste and smell, and transmit them to the brain in the form of nerve impulses.
The essential difference between what is termed general sensibility and the special senses lies in the fact that the organs of special sense are each sensitive to a specific stimulus which does not affect the general sensory apparatus of the body surface to an appreciable degree.
Thus, the waves of light or of sound, flavoured substances which have a taste, and the minute particles which stimulate the sensory organ for smell — all these varied stimuli create no impression when they come into contact with the sensitive general surface of the body.
the sensation is that of vibration and not of sound.
This difference in function between the ordinary and the special senses as well as the difference between the individual organs of special sense, is associated with a difference in structure; for each special sense organ has a characteristic receptive mechanism of cells highly specialised in form and structure, which receive the stimuli coming from without, and transmit them to the brain in the form of a nerve-current. These cells may be derived by the specialisation of certain cells coming directly from the surface of the body, or they may be cells derived from the central nervous system — as in the case of the eye. In this case, the cells are placed in close relation to the terminals of a special cranial nerve.
Many of the sense organs, and especially the eye and ear, are highly complex in structure. The complexity is due largely to the elaborate mechanical arrangement for receiving the external stimulus, and for conveying it to, or focussing it upon, the sensory cells proper.
It must always be borne in mind that sensation itself is a function of the brain — it is the response in consciousness to the afferent impressions transmitted to the brain by the sensory nerves. Further, the quality of the sensation does not arise in the sense organ, but in the brain itself. Thus, stimulation of the trunk of the optic nerve by mechanical means produces sensations of light, apart from stimulation of the retina.
The olfactory apparatus [organon olfactus] in man does not reach the high development which is found in many of the lower animals. In them, not only is the sensory apparatus found distributed over a large area of the nasal mucous membrane, but the central connections of the olfactory nerves make up a considerable portion of the brain, including all those structures known under the name of rhinencephalon. In man, sensibility to smell is localised to a comparatively limited area in the upper part of the nasal cavity, known as the olfactory area.
septum.
Fig. 792 shows the size of this area, and it will be noticed that the area on the lateral wall of the nose does not coincide with the area of the superior concha, but is rather smaller. It should be added that the olfactory nerves can be traced to a somewhat larger area of the mucous membrane, to the middle concha; it is, therefore, possible that the area indicated is too small.
The olfactory apparatus within it consists of the olfactory cells. These cells are elongated spindle-shaped structures, lying between the deeper parts of the investing columnar cells. From each a slender process passes to the surface of the mucosa, and terminates in a group of short hair-like processes, the olfactory hairs (v. Bumm), while from the deep portion of the cell a long slender process passes deeply into the mucosa. These processes resemble nerve filaments, with no medullary sheath, and they pass in the olfactory nerves to the olfactory bulb, in which they terminate in arborisation around the dendritic enlargements of the mitral cells of the olfactory bulb (see fig. 795; also Olfactory Nerve, p. 929).
dealt with in the section on the Nervous System.
The development of the olfactory organ is connected with the development of the nose, which represents at first only the olfactory portion. About the third week, a localised thickening of the surface epithelium occurs on the antero-ventral aspect of the head in the region of the fore-brain, forming on each side an olfactory plate. These plates become depressed from the surface by the growth of the margins, giving rise to the olfactory pits. The further changes are
THE EYE
associated with the formation of the face and nose (see Morphogenesis). The cells of the surface epithelium on the olfactory pits in part form olfactory cells, and send processes inward which pass to the olfactory lobe of the brain, and form the olfactory nerve.
The organ of Jacobson is a small rudimentary structure in man. It is represented by a minute canal, 2 to 9 mm. long, placed on each side in the lower portion of the nasal septum, opening on the surface slightly above the orifice of the naso-palatine canal. The canal is lined by epithelium, but contains no olfactory cells. It is developed from a small portion of the olfactory plate which becomes separated from the area which gives rise to epithelium of the olf actor j' region.
II. ORGAN OF TASTE
The taste organs [organon gustus] consist of minute epithelial structures, the taste buds [calyculi gustatorii], situated mainly in the epithelial covering of the tongue and also in the epiglottis.
In the tongue, the taste buds are found mainly on the walls of the vallate papillse (see p. 1106), but they are found to a slight extent scattered over the whole area of distribution of the glosso-pharyngeal nerve, on the surface of the foliate and fungiform papillse, and on the plicse fimbriatse on the lower surface of the tongue.
AND the Olfactory Mucosa.
In the foetus, the distribution is even wider, and they have been described as occurring on the soft palate, palatine arches, uvula, and in the mucous membrane covering the medial surfaces of the arytenoid cartilages. It is possible that such structures, though found in these regions in the foetus, usually disappear in the adult.
Each taste bud is a hollow conical or oval structure, measuring .07-.08 mm. in length. At one end it opens by a small channel, termed the pore canal, which passes to the surface between adjacent epithelial cells. The surface opening is termed the outer -pore and the opening at the taste bud the inner taste pore.
The taste bud consists of epitheUal supporting, of gustatory and of basal cells, arranged as seen in figure 794. The gustatory cells are long slender fusiform cells. The free end of each passes to the inner taste pore, and terminates in stiff hair-like processes, which project toward the pore canal. The deep end of each is connected with a basal cell. Terminal branches of the glosso-pharyngeal nerve ramify around the gustatory cells, and convey to the brain the impulses generated by contact of the ends of these cells with sapid particles. The epithelial supporting cells line the taste buds, and also project into the interior between the olfactory cells.
Development. — The taste buds appear comparatively late in embryonic life — about the third month. They arise mainly from the entodermal portion of the tongue, b}' differentiation of the deeper cells of the epithelial covering over localised areas. Around these cells terminations of the glosso-pharyngeal nerve are found. These cells assume the characteristic shape and arrangement of the adult to form a taste bud. At first the opening of the bud lies upon the surface, but as the surrounding epithelial cells increase in size and thickness, the pore-canal is formed as a space between adjacent epithelial cells on the summit of the bud.
SPECIAL SENSE ORGANS
which processes pass to the brain in the optic nerve. The eyeball is a hollow spherical structure, whose wall is formed externally by a fibrous tunic including the sclera (the white of the eye), and the cornea (the transparent area in the anterior aspect of the eyeball). Internal to the tunic formed by these membranes is a pigmented vascular membrane, the chorioidal membrane, of which the anterior part forms the iris, or the coloured part of the eye.
Within these tunics is formed a cavity, in which lies the crystalline lens of the eye. In front and behind the lens are two chambers; that in front of the lens contains the aqueous humour and that behind it the vitreous.
General Surface View
The two eyes are situated nearly in the line where the upper and middle thirds of the face meet; they lie right and left of the root of the nose, the most prominent part of the front of each globe being about 3 cm. (1 J in.) from the mid-line of the face. Each eye is overshadowed by the corresponding eyebrow, and is capable of being concealed by its eyehds, upper and lower.
The orbital margin may be traced all round with the finger. At the junction of the medial and intermediate thirds of the upper margin the supraorbital notch (incisura supraorbitalis) can usually be felt, and the supraorbital nerve passing through it can sometimes be made to roll from side to side under the finger. The medial margin is the most difficult to trace in this way, partly because it is more rounded ofi' than the others, partly because it is bridged over by a firm band (medial palpebral ligament), passing medially from the medial angle of the eyelids; below this band, however, a sharp bony crest is felt, which lies anterior to the lacrimal sac. Note how the eye is protectedby the rim of the orbit, above and below; if we lay a hard flat
Fig. 796. — View of the Eye with Eyelids Open. Palpebra superior (pars tarsalis) Cilia I Sulcus orbitopalpebralis superior Sclera r ' I Angulus oculi medialis
Palpebra inferior
body over the orbital opening, it will rest upon the upper and lower bony prominences, and will not touch the surface of the globe. Medially, the eye is protected from injury mainly by the bridge of the nose; laterally it is most readily vulnerable, as here the orbital rim is comparatively low. With one finger placed over the closed upper lid, press the eyeball gently backward into the orbit, and observe the elastic resistance met with, due to the fact that the globe rests posteriorly on a pad of fat.
The space between the free edges of the upper and lower lids is known as the palpebral aperture [rima palpebrarum]: it is a mere slit when the lids are closed; but when they are open its shape is, roughly, that of an almond lying with its long axis horizontal, and about thirty millimetres in length.
When the eyes are directed to an object straight in front of them, this aperture is about twelve millimetres wide, but its width varies with upward and downward movements of the eyeball, being greatest on looking strongly upward, diminishing gradually as the eye looks progi'essively lower. The angles formed by the meeting of the lids at each end of the palpebral aperture are named respectively the lateral and medial angles (or canthi) [angulus oculi lateralis, medialis], of which the lateral is sharp, while the medial is rounded off. On a closer inspection, it will be found that, for the last five millimetres or so before reaching the medial angle the edges of the lids run an almost parallel course, and are here devoid of lashes. Through the open palpebral aperture the front of the eyeball comes into view, extending quHe to the lateral, but not reaching as far as the medial, angle; just within the latter we find a small reddish prominence, the lacrimal caruncle [caruncula lacrimalis] ; and between this and the eyeball a fold of
SURFACE VIEW OF THE EYE
conjunctiva known as the plica semilunaris. While the eye is open, press one finger on the skin, a little beyond the lateral angle, and draw it firmly away from the middle line; observe that the upper lid then falls over the eyeball, and that the outline of a firm band already referred to (the medial palpebral ligament) becomes evident, passing between the medial angle and the nose. The falling of the lid is caused by our dragging upon a ligament (the lateral palpebral raph6) to which the lateral end of its tarsus is attached, and so putting the lid itself upon the stretch. If, while the eyeball is directed downward, we place one finger on the lateral end of the upper eyelid and draw it forcibly upward and laterally, we can usually cause the lower division of the lacrimal gland to present just above the lateral angle.
The upper eyelid [palpebra superior] is much broader than the lower, extending upward as far as the eyebrow. The skin covering it is loosely attached to the subjacent tissues above, but more firmly below, nearer the free margin, where it overlies a firm fibrous tissue called the tarsus superior. When the eye is open, a fold is present at the upper border of this lower more tightly applied portion of skin, called the superior palpebral fold, and by it the lid is marked off into an upper or orbital, and a lower or tarsal, division. The presence of the tarsus can be readily appreciated on our pinching horizontally the entire thicloiess of the eyelid below the palpebral fold. The lower eyelid [palpebra inferior] is similarly divided anatomically into a tarsal and an orbital part, but the demarcation is sometimes unrecognisable on the surface,
though a fold or groove (the inferior palpebral) is usually visible when the eye is widely opened. There is no precise limit of this lid below, but it maybe regarded ase.xtending to the level of the lower margin of the orbit. Numerous very fine short hairs are seen on the anterior surface of both eyelids. Each eyelid presents an anterior and a posterior surface, separated by a free margin with two edges: — (a) An anterior, rounded edge [limbus palpebralis anterior] along which the stiff cilia, or eyelashes, are closely placed in a triple row; and (b) a sharp posterior edge [limbus palpetjralis posterior] which is applied to the surface of the globe (see fig. 813). The cilia of both eyeUds have their points turned away from the palpebral aperture, so that the upper ones curve upward, and the lower downward; the oiha of the upper lid are the stronger,
and those in the middle of each row are longer than those at each end. Between the two edges just described, the Ud-margin has a smooth surface, on which is a single row of minute apertures, the openings of large modified sebaceous glands, the tarsal or Meibomian glands. It is by these glistening, weU-lubricated surfaces that the opposite lids come into apposition when they are closed. The secretion of these glands is known as the sebum palpebrale. The sharp posterior edge of the lid-margin marks the situation of the transition of skin into mucous membrane. Near the medial end of the margin of the lids we find a prominence, the lacrimal papilla, on the summit of which is a small hole [punctum lacrimale], the opening of the lacrimal duct (ductus lacrimaUs) for the passage of tears into the lacrimal sac. The lower punctum is rather larger than the upper, and is placed further from the medial angle of the eye.
If we now examine the posterior surface of the eyelids — e. g., of the lower — we observe that it is lined by a soft mucous membrane, the palpebral conjunctiva [tunica conjunctiva palpebrarum]. Over the tarsal part of the lid the conjunctiva is closely adherent, but beyond this it is freely movable along with the loose submucous tissue here present. On tracing it backward, we find that it covers the whole posterior surface of the hds, and is then continued forward over the front of the eyeball, forming the conjunctival tunic of the globe [tunica conjunctiva bulbi]. The bend it makes as it changes its direction here is called the conjunctival fornix [fornix oonjuuotivEe superior or inferior]. Numerous underlying blood-vessels are visible through the palpebral conjunctiva, and under cover of its tarsal part we can see a series of nearly straight, parallel, light yellow lines, arranged perpendicularly to the free margin of the hd — the tarsal glands. The conjunctiva over the medial and lateral fourths of each lid is not quite so smooth as elsewhere, and is normally of a deeper red colour; we shall find later that there are glands well developed in these positions.
When the eyelids are opened naturally, we see through the palpebral aperture the following: the greater part of the transparent cornea, and behind it the coloured iris with the pupil in its centre; white sclera to the medial and lateral sides of the cornea; the semilunar fold and lacrimal caruncle at the medial angle. The extent of the eyeball visible in this way varies according to its position. Thus, with the eyes looking straight forward, the lower margin of the upper Ud is nearly opposite to the top of the cornea, or, more strictly, to a line midway between the top of the cornea and the upper border of the pupil, while the lower lid corresponds with the lower margin of the cornea. When the eyes are directed strongly upward, the upper lid is relatively on a slightly higher level, as it is simultaneously raised, but the lower lid now leaves a strip of sclera exposed below the cornea. On looking downward the upper lid covers the upper part of the cornea as low down as the level of the top of the pupil, while the lower hd is about midway between the pupil and the lower margin of the cornea.
If we draw the eyelids forcibly apart, we expose the whole cornea, and a zone of sclera about eight and a half milhmetres in breadth above and below, and ten milHmetres in breadth to the lateral and medial sides — altogether about one-third of the globe; all the eyeball thus exposed is covered by the ocular conjunctiva [tunica conjunctiva bulbi]. Over the sclera the conjunctiva is freely movable, and through it we see superficial blood-vessels that can be made to slip from side to side along with it (episcleral vessels). Occasionally other deeper vessels may also be seen which do not move with the conjunctiva, but are attached to the sclera (anterior ciliary arteries and veins). Near the corneal border the conjunctiva ceases to be fieely movable, and it is closely adherent to the whole anterior surface of the cornea, giving the latter its characteristic bright, reflecting appearance; no blood-vessels are visible through it here in health. When the lids are shut, the space enclosed between their posterior surfaces and the front of the eyeball is thus everywhere lined by conjunctiva, and is known as the conjunctival sac.
Not unfrequently the tendinous insertions of some or aU of the recti muscles into the sclera may be seen through the conjunctiva, each insertion appearing as a series of whitish parallel lines running toward, but terminating about seven mUhmetres from, the corresponding corneal border.
The cornea appears as a transparent dome, having a curvature greater than that of the sclera; the junction of the two unequally curved surfaces is marked by a shallow depression running around the cornea, known as the scleral sulcus [sulcus sclerse]. In outline the cornea is nearly circular, but its horizontal diameter is slightly greater than its vertical. Between it and the iris a space exists, whose depth we can estimate roughly by looking at the eye from one side; this space, or anterior chamber [camera ocuh anterior] is occupied by a clear fluid, the aqueous humour. Almost the whole anterior surface of the iris is visible, its extreme periphery only being concealed by sclera.
In colour the iris varies greatly in diiferent individuals. Near its centre (really a little up and in) a round hole exists in the iris, the black pupil [pupUla], whose size varies considerably in different eyes, and in the same eye according to temporary conditions, such as exposure to light, etc.
On the surface of the iris we see a number of ridges [plicae iridis] running more or less radially ; adjoining ones occasionaUy unite and interlace to some extent, so as to leave large depressed meshes at intervals. These are the crypts of the iris. The radial ridges coming from the edge of the pupil, and those coming from the more peripheral part of the iris, meet in a zigzag elevated ridge concentric with the pupil, called the corona iridis, and by this ridge the iris is roughly marked off into two unequal zones — an outer, the greater [annulus U'idis major] and an inner, the lesser [annulus iridis minor]. The border next the pupil [margo pupillaris] is edged with small, roundish, bead-like prominences of a dark brown colour, separated from one another by depressions, so that it presents a finely notched contour. Not infrequently, in a light-coloured iris, we may see the sphincter muscle through the anterior layers, in the form of a ring about one millimetre in breadth around the pupil. The annulus iridis major may be described as consisting of three parts: — (a) A comparatively smooth zone next the zigzag ridge; (6) a middle area, showing concentric but incompletely circular furrows; (c) a small peripheral darker part, presenting a sieve-like appearance. On the floor of the large depressed
meshes, or crypts, parallel radial vessels can be traced, belonging to the iris-stroma. The zigzag line mentioned above corresponds to the position of the circulus arteriosus minor. Occasionally, especially in a hght iris, superficial pigment spots of a rusty brown colour occur.
The general red reflex obtained from the fundus is due to the blood in a capillary network (chorio-capillaris) situated in the inner part of the chorioid. To the nasal side of the centre of the fundus is a paler area of a disc shape corresponding to the intraocular end of the optic nerve, and known as the papilla of the optic nerve [papilla n. optici]. This papilla (or 'optic disc') is nearly circular, but usually slightly oval vertically; it is of a light orange-pink colour, with a characteristic superficial translucency; its lateral third segment is paler than the rest as nervefibres and capillaries here are fewer in number. About its centre we often observe a weUmarked whitish depression [excavatio papillae n. optici], formed by the dispersion of the nervefibres as they spread out over the fundus; at the bottom of this depression a sieve-like appearance may be seen, due to the presence of the lamina cribrosa sclerae, which consists of a white fibrous tissue framework, with small, roundish, light-grey meshes in it, through which the nerve-fibre bundles pass. Also near the centre of the papiUa, the retinal blood-vessels first come into view, the arteries narrower in size and lighter in colour than the veins; they divide dichotomously as they are distributed over the fundus. The retina proper is so transparent as to be ophthalmoscopically invisible, but its pigment-epithelium gives a very finely granular or darkly stippled appearance to the general red reflex. In the centre of the fundus, and therefore to the lateral side of the papilla, the ophthalmoscope often shows a shifting halo of light playing round a
the fovea centralis.
Two structures visible at the nasal end of the palpebral aperture have been previously mentioned, and should now be examined more narrowly. The lacrimal caruncle is an island of modified skin, and fine hairs can commonly be detected on its surface, and it contains sebaceous and sweat glands. Lateral to it and separated from it by a narrow groove, is the semilunar fold of conjunctiva; it rests on the eyeball, and is a rudiment of the third eyelid or nictitating membrane, present in birds and well represented in many other vertebrates.
The eyeball [bulbus oculi] is almost spherical, but not perfectly so, mainly because its anterior, clear, or corneal segment has a greater curvature than the rest of the eye. Considering it as a globe, it has an anterior pole [polus anterior] and a posterior pole [polus posterior]; the former corresponding to the centre of the front of the cornea, the latter to the center of the posterior curvature. An imaginary straight line joining the two poles is called the axis of the eyeball. The equator of the eye is that part of its surface which lies midway between the two poles. The various meridians are circles which intersect the poles. The sagittal axis of the globe is the greatest (about 24 . 5 mm.), the vertical equatorial the least
(about 23.5 mm.), and the transverse equatorial axis is intermediate in length (about 23 . 9), so that the eyeball is in reality an ellipsoid, flattened slightly from above downward. These figures refer to the adult male; in the female the eyeball is . 5 mm. smaller in aU axes. Again, if the globe is divided in its mid-sagittal plane, the nasal division will be found to be slightly smaller than the temporal. The optic nerve joins the globe three or four millimetres to the nasal side of the posterior pole.
The shape of the eye depends on, and is preserved by, the outermost tunic, formed conjointly by the cornea and sclera, the entire outer surfaces of which are now in view. The anterior or corneal part has already been examined. In front of the equator we see the tendinous insertions of the four recti muscles. Behind the equator are the insertions of the two oblique muscles — that of the superior oblique tendinous, and further forward; that of the inferior more fleshy, and placed between the optic nerve and the lateral rectus.
It is difficult to recognise the different recti muscles by their insertions if we do not know whether the eye examined is a right or a left one. To determine this we should hold the globe with the optic nerve toward us, and in the natural position with the superior oblique tendon uppermost. The inferior oblique tendon will now point to the side to which the eye belongs, and we can consequently determine the difTerent recti muscles.
The medial [m. rectus medialis] rectus is inserted nearest (5.5 to 7 mm. from) the corneal border; the superior [m. rectus superior] rectus commonly, sometimes the lateral [m. rectus laterahs], is inserted furthest from it (7.7 to 8 mm.). All the recti tendons are broad and thin, but that of the medial is the broadest (8 to 10.3 mm.); those of the lateral and inferior the narrowest (6 to 9.2, or 9.8 mm., respectively). The greatest interval between two neighbouring tendons is that between the superior and medial recti (about 12 mm.); the least is between the superior and lateral (7 mm.). The form of the lines of insertion of the different tendons varies considerably, the inferior being almost straight, the superior and lateral convex forward, the medial further removed from the corneal border below than above.
The insertions of the oblique muscles [mm. obliqui] are at more than double the average distance of the insertions of the recti from the corneal border. That of the superior oblique is found on the superior surface of the sclera, about sixteen millimetres from the corneal edge, in the form of a line 10.7 mm. long sloping from before backward and medially. The inferior oblique has a long fleshy insertion lying between the lateral rectus and the optic nerve entrance; the posterior end of the insertion, which is also the higher, is only about five to six millipietres from the optic nerve, and from this point it slopes forward, laterally, and slightly downward.
Several small nerves and two arteries may be seen running forward and ultimately perforating the sclera not far from the entrance of the optic nerve. The two arteries are the long posterior ciliary [aa. ciliares posteriores longi] ; they both perforate the globe in the horizontal meridian, 3.5 mm. from the optic nerve, one on the lateral, the other on the medial, side. The short ciliary arteries [aa. ciliares
THE EYEBALL 1057
posteriores breves] are too small to be seen in an ordinary examination. The nerves are the long and short ciUary [nn. ciliareslongi, breves]. Nearer the equator large venous trunks emerge; they can be traced for some distance in front of their exit as dark lines, running antero-posteriorly internal to the sclera. The optic nerve is seen in section, surrounded loosely by a thick outer sheath; in the centre of the nerve-section a small red spot indicates the position of the central retinal blood-vessels [a. et v. centralis retinae].
1. Posterior hemisphere seen from in front. — This is much the same view that the ophthalmoscope affords us. Unless the eye be very fresh, however, the retina will have lost its transparency, and will now present the appearance of a thin whitish membrane, detached in folds from the external coats, but still adherent at the optic papilla. The vitreous jelly lying within the retinal cup may be torn away. In the human eye the retina next the posterior pole is stained yellow [macula lutea]. On turning the retina over, a little pigment may be seen adhering to its outer surface here and there. Cut through the retina close to the optic disc all around and remove it: note how easily it is torn. We now see a dark brown surface, consisting of the retinal pigment layer [stratum pigmenti retinas] adherent to the inner surface of the chorioid. Brush off the retinal pigment under water. The chorioid thus exposed can for the most part be fairly easily torn away from the thick sclera, as a lymph-space exists between them, but the attachment is firm around the optic nerve entrance, and also where the arteries and nerves join the chorioid after penetrating the sclera. The chorioid is darkly pigmented, of a brown colour, with markings on its surfaces corresponding to the distribution of its large veins. The inner
Ciliary processes
surface of the sclera is of a light brownish colour, mainly from the presence of a delicate pigmented layer, the lamina suprachorioidea, which adheres partly to it, partly to the chorioid, giving to their adjacent surfaces a flocculent appearance when examined under water.
2. Anterior hemisphere viewed from behind. — The round opening of the pupil is visible in the middle, in front of the large clear crystalline lens. The retina proper extends forward a little way from the line of section, and then ends abruptly in a wavy line called the era serrata, beyond which it is only represented by a very thin membrane [pars ciliaris retinae]. Outside the periphery of the lens are a number of ciliary processes arranged closely together in a circle concentric with the pupil, and each radially elongated; posteriorly they are continuous with n umerous fine folds, also radial, which soon get very indistinct as they pass backward, but reach almost to the ora serrata [plicae ciliares]. Between the front of the ciliary processes and the edge of the pupU lies the iris. On removal of the retina the inner surface of all this region is seen to be darkly pigmented, but especially dark in front of the position of the ora serrata. Vitreous probably still adheres to the back of the lens, and by pulhng upon it the lens can be removed along with its capsule and suspensory ligament; some pigment will now be found adhering to the front of the vitreous, torn from the ciliary processes, which are consequently now lighter in colour than before. The lens-capsule is transparent, and has a smooth glistening outer surface; through it a greyish, star-shaped figure may be observed on the anterior and posterior surfaces of the lens. The suspensory ligament is a transparent membrane attached to the capsule of the lens about its equator, and is best seen by floating the lens in water in a glass vessel placed on a dark ground. On opening the capsule we expose the lens itself, which is superficially soft and glutinous to the touch, but becomes firmer as we rub off its outer laj-ers and approach its centre. Carefully tear the chorioid and iris from the sclerotic as far as possible; a firm adhesion exists just behind the corneal periphery. The outer surface of the chorioid thus exposed is found to be also rather darkly pigmented, taut it shows a white ring corresponding to the adhesion just mentioned, and a pale area behind this ring indicates the position of the ciliary muscle [m. ciharis]. On this surface numerous white nerve-cords are visible running
forward. Observe that the iris, the ciliary processes, etc., and the chorioid are all different parts of the same ocular tunic — mere local modifications of it. Similarly the sclera and cornea are seen to blend together to form one outer coat.
An eyeball should now be placed for half an hour in a freezing mixture of crushed ice and salt. It will thus become quite hard, and should at once be divided into two parts by cutting it antero-posteriorly through the centre of the cornea and the optic nerve. We thus gain another view of the relations of parts, the position of the lens between the aqueous and vitreous chambers, etc. On removing the lens, vitreous, and retina, and brushing off its pigment, the light markings corresponding to the chorioidal veins (venae vorticosse) should be noted, and their distribution studied. Usually four vortices or fountain-like markings are found in the whole chorioid,
Sclera
their points of junction situated at approximately equal distances from one another at about the hne where the posterior and middle thii-ds of the globe meet. These sections should be kept for reference while following the further description of the ocular tunics.
The coats of the eyeball. — 1. The outer, fibrous coat of the eye [tunica fibrosa oculi] is formed by the sclera and cornea, which pass into one another at the scleral sulcus. It consists throughout mainly of fine connective-tissue fibres, arranged in interlacing bundles, with small lymph-spaces at intervals between them. The naked-eye appearance of the two divisions of this fibrous coat is, however, quite different, the cornea being transparent, while the sclera is white and opaque.
The fibre-bundles composing the solera are arranged more irregularly than in the cornea, and run mainly in two directions, viz., antero-posteriorly and circularly; the circular fibres are particularly well developed just behind the sulcus. It is thickest (about 1 mm.) posteriorly, where it is strengthened chiefly by the outer sheath of the optic nerve, and partly also by the tissue surrounding the ciliary vessels and nerves. It becomes gradually thinner as it passes forward, up to the line of insertion of the I'ecti muscles, where it is .3 mm. thick. In front of that line it is again reinforced by their tendinous fibres becoming incorporated with it and its thickness increases to .6 mm. In children the sclera is often so thin as to allow the underlying chorioidal pigment to show through, its colour then appearing bluish white. In the aged, again, it is sometimes yellowish. It always contains a few pigment cells, but these are in the deep layer termed the lamina fusca, and only become visible externally where the sclera is pierced by vessels and nerves going to the chorioid. It is almost non-vascidar, but quite at its anterior end a large venous sinus [sinus venosus sclerse; canalis Schlemmi (Lauthi)], (canal of Schlemm) runs in its deeper layers circularly around the cornea. Just in front of this sinus, at the corneal limbus, the sclera merges into the cornea, its inner layers changing first, and finally the outer ones.
rectus lateralis
The cornea forms the anterior sixth of the eyeball. It is thickest ,'at its periphery (1.1 mm.) and becomes gradually thinner toward its centre (0.8 mm.); the curvature of its posterior is consequently greater than that of its anterior surface, but even the latter is more curved than the surface of the sclera.
In the cornea proper, fibre-bundles are arranged so as to form a series of superposed lameUse, each of which is connected here and there to the adjacent ones by fibres passing from one to the other, so that they can only be torn apart with difficulty. The corneal lymph-spaces communicate with one another by very fine canals, and thus not only is a thorough lymph-circulation provided for, but the protoplasm with which these spaces are partially occupied may be also regarded as continuous throughout. It contains no blood-vessels, with the exception of a rich plexus at its extreme periphery, on which its nutrition is ultimately dependent. The sinus venosus o} Schlemm is an important channel for the return of blood and also of fluid which transudes into it from the anterior chamber. It consists of a network of venous spaces, formed of a principal vessel accompanied by several smaller ones, which unite with it and with one another in a plexiform manner. -They commence indirectly with the spaces of the angle of the iris and they are in direct communication with the anterior ciliary veins.
The outer surface of the cornea is covered by an extension of the ocular conjunctiva, in the form of an epitheUum several layers deep. The most external part of the true cornea appears homogeneous, even when highly magnified and constitutes the anterior elastic lamina, Bowman's membrane, though there is reason to believe that its structure only differs from that already described in the closeness of its fibrous texture; the two parts are certainly connected by fine fibres. Posteriorly, the cornea is lined by a fu-m, thin, glass-hke layer (posterior elastic lamina, membrane of Descemet), distinct from the corneal tissue both anatomically and chemically. At the periphery this membrane breaks up into a number of fibres, which mainly arch over to join the base of the iris and form part of the ligamentum pectinatum iridis. The pectinate ligament is an open network of interlacing fibres, directly continuous with the circular and longitudinal bundles of sclera surrounding the venous sinus of Schlemm (Henderson). The interstices between these fibres constitute spaces (spaces of Fontana) [spatia anguli iridis (Fontanse)] freely communicating with the aqueous chamber on the one hand, and indirectly with the venous sinus of the sclera on the other. The posterior elastic lamina is in turn lined by a single layer of flat cells, which are continuous peripherally with cells lining the spaces of the angle and the anterior surface of the iris which form the endothelium of the anterior chamber. The cornea is richly supplied with nerves, particularly in its most superficial layers.
2. The dark, middle, or vascular coat of the eye [tunica vasculosa oculi] i? formed by the iris, ciliary body, and chorioid. It is closely applied to the sclera, but actually joins it only at the anterior and posterior limits of their course together, viz., at the scleral sulcus, and around the optic nerve entrance. It is separated from the sclera between these two points by a narrow slit-like lympspace [spatium perichorioideale]. In front of the sulcus, the middle coat is separated from the outer (i. e., the iris from the cornea) by a considerable space filled with fluid, caUed the anterior aqueous chamber. The vascular coat has two openings in it; a larger one in front, the pupil, and a smaller one behind, for the passage of the optic nerve. Its structure is that of a pigmented connective tissue, supporting numerous blood-vessels and containing many nerves and three deposits of smooth muscle-fibres.
The chorioid [chorioidea] forms the posterior part of the vascular coat, and extends, with slowly diminishing thickness, forward as far as the ora serrata. Its outer and inner surfaces are botli formed by non-vascular layers; that covering the outer, the lamina suprachorioidea, is pigmented, arranged in several fine loose lamelte; that covering the inner surface is a thin, transparent, homogeneous membrane, called the basal lamina of the chorioid. The intervening chorioidal stroma is very rich in blood-vessels, which are of largest size next its outer surface constituting the lamina vasculosa. These become progressively smaller toward the basal lamina, next to which is a layer of closely placed wide capillaries, called the lamina choriocapillaris. The pigment becomes less in amount as we pass inward, and finally ceases, being absent entirely from the choriocapillary and basal laminae.
In front of the ora serrata the vascular coat becomes considerably modified' and the part reaching from the ora serrata of the retina to the iris is termed the ciliary region of the tract, or ciliary body [corpus ciliare]. Its superficial aspects have been already briefly described. In front, the cihary processes, about seventy in number, project toward the interior of the eye, forming the corona ciliaris. Behind this part lies the orbiculus ciliaris, whose inner surface is almost smooth, faint radial folds [plic£e ciliares] only being present, three or four of which join each ciliary process.
The more minute structure of this ciliary region resembles closely that of the chorioid, except that the chorio-capillaris is no longer present, that the stroma is thicker and richer in bloodvessels, and that a muscular element (ciliary muscle) exists between the vascular layer and the lamina suprachorioidea. On antero-posterior section the ciliary body is triangular; the shortest side looks forward, and from about its middle the iris arises; the two long sides look respectively inward and outward, the inner having the ciliary processes upon it, while the outer is formed by the ciliary muscle. This muscle possesses smooth fibres and consists of an outer [fibrfe meridionales (Brueckei)] and an inner division [fibra; circulares (Muelleri)]. The meridional fibres take origin from the outer fibrous coat of the eye at the sclero-corneal junction in front, and passing backward to join the outer layers of the orbiculus ciliaris and chorioid; the circular fibres are situated next to the ciliary processes. The entire muscle is destitute of pigment, and therefore is recognisable in the section by its light colour. The whole thickening of the vascular tunic in this region, muscle and folds and processes together, is named the ciliary body. It includes the corona ciliaris, formed of the ciliary processes and folds, and the orbicularis ciliaris containing the ciliary muscle.
The iris projects into the interior of the front half of the eye in the form of a circular disc perforated in the middle. The appearance of its anterior surface has already been described. The anterior surface is covered with a layer of endothelium except at the crypts near the cihary border. Thus the lymph spaces between the stroma cells communicate directly with the anterior chamber. Its posterior
surface exhibits numerous radial folds running from the ciliary processes to near the pupillary margin; a thick layer of black pigment covers it and curls around this edge, so as to come into view all around the pupil as seen from in front. The ciliary border of the iris is continuous with the front of the ciliary body, and there it also receives fibres from the ligamentum pectinatum iridis; in other respects the iris is quite free, merely resting on the front of the lens-capsule near the pupil.
Its stroma [stroma iridis] is spongy in character, being made up of vessels covered by a thick adventitia, running from the periphery to the pupillary border, with interspaces filled by branching pigment cells, which are particularly abundant near the front surface. Deep in the stroma, running around near the pupillary border, we find a broad flat band of smooth muscle-fibres, constituting the m. sphincter pupillse. Immediately behind the vascular tissue hes a thin membrane, consisting of fine, straight fibres running radially from the ciliary border to the stroma behind the sphincter. The nature of these fibres was long in dispute, but they are now accepted as being undoubtedly smooth muscular — and comprise the m. dilatator pupillae.
The m. sphincter pupiUos and the ciliary muscle are supplied indirectly by the oculomotor nerve through the ciliary ganglion. The dilatator pupillae is supplied by sympathetic fibres , which have their origin from the cells of the superior cervical ganghon. Thence they ascend in the carotid and cavernous plexuses, and join the ophthalmic division of the trigeminal nerve, passing to the eyeball by way of the long ciliary nerves. The pre-ganglionic sympathetic fibres leave the spinal cord by the motor roots of the first two or three thoracic nerves, and ascend the sympathetic trunlv to the superior cervical ganglion without interruption.
The posterior surface of the iris is lined by pigment already mentioned, consisting of two layers of pigmented cells, each layer representing the extension forward of one subdivision of the retina. The anterior surface of the iris is covered by a delicate epithehal layer, continuous with the ceils of the posterior elastic lamina of the cornea. The colour of the iris in different individuals depends upon the amount of stromal pigment.
Developmentally this general pigment lining is quite distinct from the vascular coat, and represents the outer wall of the secondary optic vesicle or embryonic retina; it consists of a single layer of pigmented epithelial cells. It is known as the slratum pigmenti. The amount of pigment is greatest anteriorly, over the ciliary region and iris, and there is again a small local increase posteriorly, corresponding to the macula lutea and to the edge of the optic nerve entrance. In the ciliary region these cells have recently been described as Uning numerous narrow tubular depressions in the inner part of the vascular tract, and they are said to have here a special function, viz., that of secreting the intraocular fluid.
From the manner in which the secondary optic vesicle, or optic cup, is formed, its two walls are necessarily continuous in front, at what may be termed the lip of the cup; we have just observed that the outer wall lines the vascular coat everywhere and corresponds in extent; consequently, the lip must be looked for at the edge of the pupil, i. e., at the termination of this coat anterorly. The inner wall of the cup, consequently, reaches from the lip, or pupillary edge, in front to the optic stalk or nerve behind, and is in close apposition to the pigment-epithelium; unlike the outer, however, this wall is represented in the developed eye by tissues very dissimilar in structure in different parts of its extent. Tracing it backward from the pupillary edge, we find that over the whole posterior surface of the iris it exists as a single layer of pigmented epithelium, the two layers of the cup having here produced a double layer of pigment cells. At the root of the iris the single inner layer of cells still exists; but now they become destitute of pigment, and this condition obtains over the entire ciliary region, constituting what is known as the pars ciliaris retinae. At the l^ne of the ora serrata the tissue derived from the inner wall abruptly increases in thickness, and rapidly acquires that complexity of structure characteristic of the retina proper, which extends from here to the optic nerve and is termed the pars optica retinas. It consists of several layers — nervefibres, nerve-cells, and nerve-epithelium — held together by a supporting framework of delicate connective tissue.
The nerve-epithelium is on the outer surface, immediately applied to the pigment-epithelium; at the posterior pole of the eye a small spot [fovea centralis] exists, where this is the only retinal layer represented, and where consequently the retina is extremely thin. The nervefibres run on the inner surface of the retina and are continuous with those of the optic nerve; they constitute the only retinal layer that is continued into the intraocular end of the nerve. The nerve-cells are found between these surface layers. The larger blood-vessels of the retina run in the inner layers, and none encroach on the layer of nerve-epithelium.
Within the coats mentioned, the interior of the eyeball is fully occupied by concents, which are divided into three parts, which are named according to their consistence and anatomical form. They are all transparent, as through them the light has to pass so as to gain the retina. Of these, the only one that is sharply and independently outlined is the lens, which is situated in the anterior half of the globe at the level of the ciliary processes, where it is suspended between the other contents, which fill respectively the space in front of it and the space behind it. The space in front of the lens called the aqueous chamber; that behind the lens is the vitreous chamber.
The lens [lens crystallina] is a biconvex disc, with its surfaces directed anteriorly and posteriorly; these surfaces meet at its rounded-off edge or equator [sequator lentis] which is near (but does not touch) the adjacent ciliary processes. The posterior is considerably more convex than the anterior surface; the central part of each surface is called its pole [polus anterior; polus posterior]. The lens is closely encased in a hyaline elastic capsule [capsula lentis] thicker over the anterior than over the posterior surface. Thus enclosed, it is held in position in the globe by a suspensory ligament, attached to the lens capsule near the equator of the eye, and swung from the ciliary region. Posteriorly, the lens rests in a cup
formed by the front part of the vitreous, while its anterior capsule is in contact with the aqueous fluid and lies close against the back of the pupillary margin of the iris. When in position the lens measures nine millimetres across, and about four millimetres between its poles.
On each surface a series of fine, sinuous, grey lines can be seen radiating from the pole toward the equator, called respectively the anterior and posterior stellate figures. The liiies observable on the posterior are always so placed as to be intermediate with those on the anterior surface, so that on viewing them through the lens they occupy a position corresponding to the
Venae vorticosEe. a. conj., Anterior conjunctival vessels, p. conj., Posterior conjunctival vessels.
intervals between the lines on the anterior surface. The lens-capsule is comparatively brittle, and can be readily cut through when scraped with a sharp-pointed instrument; on doing so the divided edges curl outward, away from the lenticular substance. When removed from its capsule, the outer portion of the lens is found to be soft and glutinous, but its substance gets progressively firmer as we approach the centre. This harder central part is known as the nucleus [nucleus lentis], and the surrounding softer matter as cortex [substantia corticahsj. The cortical part shows a tendency to peel off in successive layers. It consists of long fibres, the ends of which meet in front and behind at the anterior and posterior stellate figures.
of the lens, a single layer of cells intervening, called the epithelium lentis.
The zonula ciliaris or suspensory ligament of the lens is formed by a number of fine zonular fibres [fibrse zonulares] passing from the ciliary body. They are attached to the lens-capsule a little in front of and behind the equator, and the spaces included between the fibres of the ligament are termed the zonular spaces [spatia zonularia]. A continuous space, which can.be injected after death, round the margin of the lens is known as the canal of Petit. It is probably an artefact. This space is bridged across by fine intermediate suspensory fibres, and is occupied by fluid.
The vitreous body [corpus vitreum] is a transparent, colourless, jelly-like mass, the vitreous humour, enclosed in a delicate, clear, structureless membrane, called the hyaloid membrane. This latter is closely applied to the back of the posterior lens-capsule and of the suppensorj^ ligament, and to the inner surface of the pars ciliaris retinse, retina proper, and optic papilla. Although possessing some degree of firmness, the vitreous humour contains quite 98 per cent, of water, and has no definite structure.
Arteria centralis retinse
Membranes have been described in it, but these are really artificial products. In certain situations spaces e.xist in the vitreous mass, the most determinate of which runs in the form of a canal from the optic papilla to the posterior pole of the lens, corresponding to the position of the foetal hyaloid artery (hyaloid canal or canalis hyaloidea). Other very fine spaces are described running circularly in the peripheral part of the vitreous concentric with its outer surface. Microscopically, wandering cells are found in the vitreous, which often here assume pecuhar forms which the observer can, not infrequently, study subjectively.
The aqueous humour is a clear, watery fluid, occupying the space between the cornea on the one hand, and the ciliary body, zonula ciliaris, and lens on the other. The iris, projecting into this space, has both its surfaces liathed in the aqueous; but, as its inner part rests on the lens, it is regarded as <liviiling the sjiace into two parts, an anterior larger, and a posterior smaller, aqueous chamber [camera oculi anterior; posterior], which communicate freely through the pupil.
iris, and the cornea.
The nerves of the iris enter it at its ciliary border, and run toward its pupillary edge, losing their medullary sheath sooner or later, and supplying especially the sphincter muscle. The corneal nerves form an annular plexus near the limbus, from which a few twigs proceed to the sclera and conjunctiva, while most of the offsets enter and run radially in the corneal stroma, branching and anastomosing so as to form a plexus. The nerves entering the cornea are about sixty in number, each containing from two to twelve non-medullated nerve-fibres.
1. The arteria centralis retinae either comes direct from the ophthalmic artery, or from one of its branches near the apex of the orbit. Entering the optic nerve twenty miUimetres or less behind the globe, it runs forward in its axis to the end of the nerve-trunk, and then divides into branches which run in the inner layers of the retina, and divide dichotomously as they radiate toward the equator. The smaller branches lie more deeply in the retina, but none penetrate into the nerve-epithelium, so that the fovea centralis is non-vascular. In the retina, the branches of the central artery do not communicate with any other arteries, but while still in the optic nerve fine communications take place between this artery and neighbouring vessels. Thus (a) minute twigs from it, which help to nourish the axial pai-t of the nerve, communicate with those running in the septa derived from the pial sheath. Again, as the nerve passes through the sclera, it is surrounded by a vascular ring [circulus vasculosus n. optici (Halleri)], formed of fine branches derived from the short posterior cihary arteries; fine twigs passing inward from this ring to the optic nerve join the vessels of the pial sheath, and (b) an indirect communication is thus brought about between the retinal and ciliary vessels. Finally, as the nerve passes through the chorioid, there is (c) a direct connection between these two sets of vessels, the capillary network of the optic nerve being here continuous with the chorio-capillaris. Not infrequently, a branch from a short posterior ciliary artery pierces the optic papilla, and then courses over the adjoining retina (a cilio-retinal artery), supplying the latter in part in place of the central artery.
The branches of the a. centralis retina in the retina are: arteriola temporalis retinae superior, arteriola temporalis retinse inferior, arteriola nasalis retinae superior, arteriola nasalis retinte inferior, arteriola macularis superior, arteriola macularis inferior, arteriola retinae medialis.
(1) Short posterior ciliary arteries twelve to twenty in number, pierce the sclera round the optic nerve entrance, and are distributed in the chorioid. Before entering the eyeball, small twigs are given off to the adjoining sclera and to the dural sheath of the optic nerve.
(2) Two long posterior ciliary arteries, medial and lateral, piercing the sclera further from the nerve than the short ciharies, run horizontally forward between the sclera and chorioid, one on each side of the globe. On arriving at the ciliary body, they join with the anterior ciliary arteries, forming the circulus arteriosus major, which sends off branches to the ciliary processes and the iris. The long ciliaries also give twigs to the cihary muscle, and small recurrent branches run backward to anastomose with the short ciliary arteries. The arteries of the iris run radially toward the pupillary border, anastomosing with one another opposite the outer border of the sphincter and forming there the circulus arteriosus minor.
(3) The anterior ciliary arteries come from the arteries of the four recti muscles, one or two from each; they run forward, branching as they go, and finally pierce the sclera near the corneal border. Externally to the globe they send twigs to the adjoining sclera, to the conjunctiva, and to the border of the cornea. After passing through the sclera the arteries enter the ciliary muscle, where they end in twigs to the muscle and to the circulus arteriosus major, and in recurrent branches to the chorioid.
Veins. — The venous blood from almost the whole middle coat (chorioid, ciliary processes and iris, and part of the ciliary muscle) ultimately leaves the eyeball by — (1) the venae vorticosae, which have been already noticed in describing an antero-posterior section through the globe. One large vein passes backward from each vortex, piercing the sclera obliquelj'; it is joined by small episcleral veins when outside the globe.
(2) The anterior ciliary veins commence by the junction of a few small veins of the ciliary muscle; they pass outward through the sclera near the corneal border, receiving blood from the veins in connection with the sinus venosus of the sclera, and afterward from episcleral and conjunctival veins, and from the marginal corneal plexus. Finally they join the veins running in the recti muscles.
Lymphatic system of the eyeball. — Apart from those in the conjunctiva there are no Ij^mphatic vessels in the eyeball, but the fluid is contained in spaces of various sizes. These are usually divided into an anterior and a posterior set.
1. Anteriorly, we have the anterior and posterior aqueous chambers (together composing the aqueous chamber of the ej^e), which communicate freelj' through the pupil. The aqueous humour is formed in the posterior of these chambers by
transudation from the vessels of the ciliary body and posterior surface of the iris (see also page 1076). The stream passes mainly forward through the pupil into the anterior aqueous chamber, whence it escapes slowly by passing through the spaces of the angle of the iris into the venous sinus of the sclera, and thence into the anterior ciliary veins. Part of the lymph-stream passes from the posterior aqueous chamber backward into the zonular spaces, out of which fluid can pass into the lens substance, or diffuse itself into the front of the vitreous body.
In the cornea the lymph travels in the spaces already mentioned as existing between the fibre-bundles, and in the nerve-chaiinels and at the periphery of the cornea it flows off into the lymphatic vessels of the conjunctiva.
Intervaginal space
2. Posteriorly, we have (a) the hyaloid canal, between the posterior pole of the lens and the optic nerve entrance, and (6) the perivascular canals of the retina; the lymph from both of these situations flows into the spaces of the optic nerve, which communicate with the intervaginal spaces of the nerve, and thus with the great intracranial spaces. Further, between chorioid and sclera we have (c) the perichorioidal space, which gets the lymph from the chorioid, and communicates with the interf ascial space (of Tenon) outside the sclera by perforations corresponding to the vasa vorticosa and posterior cihary arteries, and with the intervaginal spaces around the optic nerve entrance. The interfascial space of Tenon, again, is continuous with the supravaginal space around the optic nerve, which conamunicates both with the intervaginal spaces, with the lymph-spaces of the orbit, and directly with the intracranial spaces at the apex of the orbit.
chiefly muscles and fat, and its posterior pole is situated midway between the base (or opening) and the apex of the orbital cavity. The anterior third of the eyeball is naturally free, except for a thin covering of the conjunctiva, and projects slightly beyond the opening of the orbit, the degree of prominence varying with the amount of orbital fat, and also to some extent with the length of the globe. A straight line joining the medial and lateral orbital margins usually cuts the eye behind the cornea — laterally behind the ora serrata, medially further forward, at the junction of the ciliary body and iris. The globe is held in position by numerous bands of connective tissue. The lacrimal gland lies under the lateral part of the roof of the orbit anteriorly. The orbital fat occupies the spaces between the orbital muscles, and is in greatest amount immediately behind the eyeball; it also exists between the muscles and the orbital walls in the anterior half of the cavity. Six muscles, viz., the four recti, the superior oblique, and the levator palpebrae superioris, arise at the apex of the orbit, and diverge as they pass forward. The recti muscles — superior, inferior, lateral, and medial — rim each near the corre-
spending orbital wall, but the superior is overlapped in part by the levator palpebrae. The superior oblique lies about midway between the superior and medial recti. A seventh muscle, the inferior oblique, has a short course entirely in the anterior part of the orbit, coming from its medial wall and passing below the globe between the termination of the inferior rectus and the orbital floor. The optic nerve with its sheaths passes from the optic foramen to the back of the eyeball, surrounded ^by the orbital fat, and more immediately by a loose connective tissue. Among the contents of the cavity are also to be enumerated many vessels and nerves and fibrous tissue septa, while its walls are clothed by periosteum (periorbita) .
The muscles of the orbit are seven in number, of which six are ocular, i. e., are inserted into the eyeball and rotate it in different directions. These ocular muscles are arranged in opponent pairs, viz., superior and inferior recti, superior and inferior obliques, lateral and medial recti. With the exception of the short inferior oblique, they all arise from the back of the orbit along with the seventh orbital muscle, the levator palpebrse superioris. All these long muscles take their origin from the periosteum in the vicinity of the optic foramen. The four recti muscles arise from a fibrous ring, the annulus tendineus communis, which arches close over the upper
and medial edge of the foramen, and extends down and out so as to embrace part of the opening of the superior orbital fissure. Their origins may be said at first to form a short, common, tendinous tube, from which the individual muscles soon separate, taking the positions indicated by their respective names. The lateral rectus has two origins from bone, one on either side of the superior orbital fissure. But in the fresh state the fissure is here bridged across by fibrous tissue, from which this rectus also springs, so that its origin is in reality continuous. The part of this fibrous ring nearest the foramen (corresponding to the origins of the superior and medial recti) is closely connected with the outer sheath of the optic nerve. The remaining two long muscles arise just outside the upper and medial part of the above-mentioned ring, and are often partially united; the levator palpebrEB tendon is in close relation to the origin of the superior rectus, while the superior oblique arises from the periosteum of the body of the sphenoid bone one or two millimetres in front of the origin of the medial rectus.
The four recti muscles lie rather close to the coi-responding orbital walls for the first half of their course, the superior rectus, however, being overlapped in part by the levator palpebrse; they then tm-n toward the eyeball, running obliquely through the orbital fat, and are finally inserted by broad, thin tendons into the sclera in front of the equator. From their respective positions in the orbit, the axis of this cone of muscles is obHque to the antero-posterior axis of the eyeball. The thickest of these muscles is the medial rectus, next the lateral, then the infe-
rior, and the superior rectus is the thinnest. As regards length, the muscular belly of the superior rectus has the longest course, and the others diminish in the order — medial, lateral, and inferior rectus. The lateral rectus is supplied by the abduoens nerve. The other three recti muscles are aU supplied by the oculomotor nerve.
The levator palpebras superioris courses along the roof of the orbit close to the periosteum for the greater part of its course, partially overlapping the superior rectus; it finally descends through the orbital fat, and widens out to be inserted into the root of the upper hd. It may be briefly described as being inserted in two distinct layers separated by a horizontal interval. The upper or anterior layer of insertion is fibrous, and passes in front of the tarsus) where it comes into relation with fibres of the orbicularis. The lower layer consists of smooth muscle (Miiller's superior tarsal muscle), and is inserted along the upper border of the tarsus. The levator has also, connections with the sheath of the superior rectus. These different insertions of the muscle will be referred to later along with the description of the orbital fasciae and of the upper eyelid. It gets its nerve supply from the oculomotor nerve, but the smooth muscle developed in its lower layer of insertion is supplied by the sympathetic nervous system. As its name expresses, its action is to raise the upper lid and to support it while the ej'e is open.
The superior oblique runs forward close to the medial part of the orbital roof until it reaches the fovea trochlearis near the medial angular process, where it becomes tendinous and passes through a fibro-cartilaginous pulley attached to the fovea just named. On passing through this pulley, or trochlea, the tendon bends at an angle of 50°, running posteriorly and laterally under the superior rectus to its insertion into the sclera. It is supplied by the trochlear nerve.
The inferior oblique arises from the front of the orbit, about the junction of its medial and inferior walls, just lateral to the lower end of the lacrimal gi-oove. It runs, in a sloping direction, laterally and posteriorly, lying at first between the inferior rectus and the orbital floor, then between the lateral rectus and the globe; finally it ascends slightly, to be inserted by a short
tendon into the sclera at the back of the eye. Its nervous supply is derived from the oculomotor nerve. The precise manner of insertion of the different ocular muscles has been described above (p. 1056). For muscles of the eyehds and eyebrows, see pp. 1077 and 1078.
Oculomotor nerve
laterally, vertically, or antero-post^riorly. In speaking, therefore, of the eye being moved upward or laterally^ etc., it is the altered position of the cornea or front of the eye that we mean to express; it is manifest that, if the cornea moves up, the back of the eyeball must simultaneously be depressed., and similarly with other movements. All the movements of the globe take
place by rotation, on axes passing through the centre. Though the possible axes are numerous in combined muscular action, there are three principal axes of rotation of the eyeball, and in reference to these the action of individual muscles must be described. Two of these axes are horizontal and one vertical; they all pass through the centre of rotation at right angles to one another. By rotation of the eye on its vertical axis the cornea is moved laterally (toward the temple) and medially (toward the nose) : movements called respectively abduction and adduc-
tion. In upward and downward movements of the cornea the eye rotates on its horizontal equatorial axis. The other principal axis of rotation is the sagittal, which we have previously described as corresponding to the line joining the anterior and posterior poles of the globe (page 1055). In rotation of the eye on its sagittal axis, therefore, the cornea may be said to move as a wheel on its axle, for its centre now corresponds to one end of the axis; in other words, this is a rotation of the cornea. Such movements may, consequently, be expressed with reference to their effect on an imaginary spoke of the corneal wheel — e. g., one- running vertically
The only two muscles that rotate the eyeball merely on one axis are the lateral rectus and the medial rectus ; the former abducting, and the latter adducting, the cornea. The action of the superior and inferior recti is complicated by the obliquity of the axes of muscles and globe previously mentioned.
abducting it.
The fasciae of the orbit [fascise orbitales]. — The orbital contents are bound together and supported by fibrous tissues, which are connected with each other, but which may conveniently be regarded as belonging to tliree systems. These are : — • (1) Those lining the bony walls; (2) those ensheathing the muscles; and (3) the tissue which partially encapsules the eyeball.
1. The orbital periosteum [periorbita], is closely applied to the bones forming the walls of the cavity, but may be stripped off with comparative ease. It presents openings for the passage of vessels and nerves entering and leaving the orbit.
M. obliquus inferior
Posteriorly this tissue is very firm, being joined by processes of the dura mater at the optic foramen and superior orbital fissure; at the optic foramen it is also connected with the dm'a sheath of the optic nerve. As it covers the inferior orbital (spheno-maxillary) fissure its fibres are interwoven with smooth muscle, forming the orbital muscle of MtiUer. From its inner surface processes run into the orbital cavity, separating the fat lobules. One important process comes from the periorbita about midway along the roof of the orbit, runs forward to the back of the upper division of the lacrimal gland, and there spUts, helping to form the gland-capsule: this capsule is joined at its medial border by other periorbital bands coming off near the upper orbital rim, and forming the suspensory ligament of the gland. On the side of the orbit the periorbita sends fibrous processes to the trochlea of the superior obUque, which keep it in position. On arriving at the lacrimal groove the periorbita divides into two layers, a thin posterior one continuing to line the bone forming the floor of the groove, whilst the thicker anterior layer bridges over the groove and the sac which lies in it, forming the limbs of the medial palpebral ligament (p. 1052).
Quite anteriorly, at the rim of the orbit, the periorbita sends off a membranous process which aids in forming the fibrous tissue of the eyelids (orbito -tarsal ligament, or palpebral fascia), and is itself continuous with the periosteum of the bones outside the orbital margin.
2. The orbital muscles are connected by a common fascia, which splits at their borders and furnishes a sheath to each. Processes of this fascia give membranous investments for the vessels and nerves (including the optic nerve), splitting simi-
fat lobules.
Posteriorly, this fascia is thin and loose, and blends with the periorbita at the origin of the muscles. Anteriorly, it becomes thicker and firmer, accompanies the muscles to near the equator of the eyeball, and there divides into two laminte, an anterior and a posterior; the former continues a forward course, forming a complete funnel-shaped investment all around, passing ultimately to the eyelids and orbital margin — whilst the latter turns backward, covering the hinder third of the globe.
The anterior lamina is a well-marked membrane everywhere, but in certain situations it presents special bands of thickening, corresponding to the direct continuation forward of the sheath of each rectus muscle. Above and below, this lamina spreads out in the form of two large membranes, which are finally applied to the deep surface of the palpebral fascia; the lower membrane constitutes what has been described as the suspensory hgament of the eyeball.' The upper membrane requires a fuller description, as its distribution is modified by the presence of the levator palpebrae muscle.
The upper part of the sheath of the superior rectus (along with the adjoining membrane on each side of it) passes to the deep surface of the levator, to which it closely adheres, and completely ensheaths this tendon by extending round its borders to its upper surface. The lower part of this levator sheath is applied to the inferior surface of the deeper of the two divisions of the levator muscle, superior tarsal muscle, and is attached to the upper border of the tarsus of the upper lid, reaching on each side to the lateral and medial angles of the orbit. The upper part of the sheath of the superior tarsal muscle reaches to the middle of the palpebral fascia, and is mainly continued forward between the muscle and the fascia to the anterior surface of the tarsus.
The lower membrane (suspensory ligament of the eyeball), joined by the sheath of the inferior rectus, reaches forward to the attached (posterior) border of the tarsus of the lower lid, where it is mainly attached, while a part of it extends to the lower palpebral fascia.
To understand the special bands of the anterior lamina mentioned above, we must follow the sheath of each rectus muscle forward, when we find that, while it is rather loosely applied to the muscular belly in its posterior two-thirds, it then suddenly becomes thicker, and is firmly attached to the muscle for some distance before finally leaving it, and is thereafter often accompanied by some muscle-fibres. The best developed of these bands, the lateral check ligament, passes anteriorly and laterally to the lateral angle of the orbit, helping to support the lacrimal gland on its way, and is inserted near the orbital edge immediately behind the lateral palpebral raphe. The medial band, or medial check ligament, is larger than the lateral, but not so thick; it passes forward and medially to be inserted into the upper part of the lacrimal crest and just behind it. These two bands, lateral and medial, come from the sheaths of the
corresponding recti muscles. From the sheath of the superior rectus come two thin bands, one from each border. The medial joins the sheath of the tendon of the superior obhque; the lateral goes to the lateral angle of the orbit, assisting in the support of part of the lacrimal gland. The sheath of the inferior rectus is thickened in front, and, on leaving the muscle, goes to the middle of the inferior oblique, splitting to enclose it; it then passes to be inserted into the lower medial angle of the orbit close behind its margin, about midway between the medial check ligament and the orbital attachment of the inferior obhque.
This is a thin, transparent tissue, situated immediately internal to the posterior lamina of the muscle-fascia. It follows the curve of the solera from the insertion of the recti to about 3 mm. from the optic nerve entrance. There it leaves the eyeball and blends with the posterior lamina of the muscle-fascia; the combined membrane may be traced backward, enveloping the optic nerve-sheath loosely, approaching it as it nears the optic foramen, but never actually joining it. The interval between it and the nerve-sheath is called the supravaginal lymph-space. The fascia bulbi first comes into relation with the muscles at the point where they are left by their proper sheaths; it there invests their tendons, forms a small serous bursa on the anterior surface of each, and adheres to the sclera along a line running around the globe, just anterior to the insertions of the four -recti muscles. Between this line and the corneal border, the conjunctiva is separated from the sclei'a by the subconjunctival tissue, strengthened by a fine expansion of the muscle-fascia.
The inner surface of the fascia is smooth, and is onlj^ connected with the sclera by a loose, wide-meshed areolar tissue. This interval between the sclera and fascia, known as the interfascial (Tenon's) space, is a Ij^mph cavitJ^ and permits free movements of the eyeball within the capsule.
Relation of the Fascia Bulbi to the Oblique Muscles. — The fascia surrounds the posterior third of the inferior oblique and its tendon, running along its ocular sm'face till it meets the fascial band coming from the inferior rectus (see above), and forming a serous bursa on the superficial surface of the oblique near its insertion. The tendon of the superior oblique for about its last five milhmetres is invested solely by the fascia bulbi; in front of this, as far as the trochlea, the tendon lies in a membranous tube derived from the muscle fascia, the inner lining of which is smooth, and may be considered as a prolongation of the fascia bulbi.
The part of this nerve with which we have here to do lies within the orbit, extending from the optic foramen to the eyeball (fig. 813). The length of this portion of the nerve is from 20 to 30 mm. and its diameter about 5 mm. Its course is somewhat S-shaped; thus, on entering the orbit, it describes a curve, with its convexity down and laterally, and then a second slighter curve, convex medially. Finally, it runs straight forward to the globe, which it enters 3 to 4 mm. to the medial side of its posterior pole.
In its passage through the optic foramen the nerve is surrounded by a prolongation of the meninges. The dura mater splits at the optic foramen, part of it joining the periorbita, while the remainder continues to surround the nerve loosely as its outer or dural sheath. The nerve is closely enveloped by a vascular covering derived from the pia mater, named accordingly the pial sheath. The space between these two sheaths is subdivided by a fine prolongation of the arachnoid (the arachnoidal sheath) into two parts, termed the intervaginal spaces [spatia intervaginalia], viz., an outer, narrow, subdural, and an inner, wider, subarachnoid space, communicating with the coiTesponding intracranial spaces. The arachnoidal sheath is connected with the sheath on each side of it by numerous fine processes which bridge across the intervening spaces. The pial sheath sends processes inward, which form a framework separating the bundles of nerve-fibres; between the enclosed nerve-fibres and each mesh of this framework there is a narrow interval occupied by lymph. The nerve-fibres are medullated, but have no primitive sheath. About fifteen or twenty millimetres behind the globe the central vessels enter, piercing obliquely the lower lateral quadrant of the nerve, and then run forward in its axis. They are accompanied throughout by a special process of the pial sheath, which forms a fibrous cord in the centre of the nerve.
On reaching the eyeball, the dural sheath is joined by the arachnoid, and turns away from the nerve to be continued into the outer two-thirds of the sclera. Similarly the pial sheath also here leaves the nerve, its greater part running into the inner third of the sclera, while a few of its fibres join the chorioid; the intervaginal spaces consequently end abruptlj' in the sclera around the nerve-entrance. In this locality the connective-tissue framework of the nerve becomes thicker and closer in its meshwork, and has been already alluded to as the lamina cribrosa sclerae. It is formed by processes passing out from the central fibrous cord at its termination and by processes passing inward from the pial sheath, sclera, and chorioid. It does not pass straight across the nerve, but follows the curve of the surrounding sclera, being therefore slightly convex backward. The nerve-trunk here quickly becomes reduced to one-half its former diam-
eter, the fibres losing their medullary sheath, and being continued henceforward as mere axiscylinders. Apart from the consequent loss of bulk, this histological change may be readUy recognised macroscopicaUy in a longitudinal section of the nerve, its aspect here changing from opaque white to semi-translucent grey. The part of the nerve within the lamina cribrosa has aheady been noted in the ophthalinoscopic examination of the Uving eye (p. 1055). The optic nerve is mainly nourished by fine vessels derived from those of the pial sheath, which run into the substance of the nerve in the processes above mentioned. In front of the entrance of the central retinal artery this vessel aids to some extent in the blood-supply of the axial part of the nerve.
work, a very short general account will suffice here.
Arteries. — The main blood-supply is afforded by the ophthalmic artery, a branch of the internal carotid, which gains the orbit through the optic foramen, where it lies below and lateral to the nerve. On entering the orbit it ascends, and passes obliquely over the optic nerve to the medial wall of the orbit; in this early part of its course it gives off most of its branches, which vary much in their manner of origin and also in their course. The ophthalmic artery gives off special branches in the orbit to the lacrimal gland, the muscles, the retina (through the optic nerve), and the eyeball, as well as to the meninges, the ethmoidal cells, and the nasal mucous membrane. Twigs from all the different branches go to supply the fat, fasciae, and ordinary nerves of the orbit. Branches which leave the orbit anteriorly ramify on the forehead and nose, and also go to the supply of
the eyelids and the tear-passages. The ophthalmic artery has many anastomoses with branches of the external carotid. The contents of the orbit are also supplied in part by the Infraorbital artery, a branch of the internal maxillary; in particular this artery supplies part of the inferior rectus and inferior oblique muscles in the cavity, and also gives a branch to the lower eyelid.
Veins. — Branches, corresponding generally to those of the artery, unite to form the superior and inferior ophthalmic veins, which ultimately, either separately or united into one trunk, pass through the superior orbital fissure and empty into the cavernous sinus. The inferior vein is connected with the pterygoid plexus by a branch which leaves the orbit by the inferior orbital fissure.
Nerves of the orbit. — These are (A) motor, (B) sensory, and (C) sympathetic, and aU enter the orbit by the superior orbital fissure, with the exception of one small sensory branch passing through the inferior orbital fissure. (The optic nerve has been already described, and is not included in this account.)
A. The motor nerves are the oculomotor, trochlear, and abducens.
1. The oculomotor nerve enters the orbit in two parts, an upper smaller, and a lower larger, division. The upper division [ramus superior] gives off two branches: one suppHes the superior rectus, entering its lower surface far back; the other branch goes to the levator palpebra?, entering its lower surface in its posterior third. The lower division [ramus inferior] divides into three branches, of which one supplies the inferior rectus, entering its upper surface
far back, and another supplies the medial rectus, entering its medial surface a little behind its middle. The third branch of the lower division gives (1) the short root to the cihary ganglion, and (2) one or more twigs to the inferior rectus, and the remainder of this branch then enters the lower surface of the inferior oblique muscle about its middle.
junction of the posterior and middle thirds of the muscle.
As regards the manner of termination of these motor nerves, it is found that in aU the ocular muscles the nerve on its entrance breaks up into numerous bundles of fibres, which form first coarse and then fine plexuses, the latter ultimately sending off fine twigs supplying the muscle throughout with nerve-endings. The posterior third of these muscles is, however, comparatively poorly supplied with both kinds of plexuses and with nerve-endings.
B. The sensory nerves are supplied by the ophthalmic and maxillary divisions of the trigeminal cranial nerve. The ophthalmic division is chiefly orbital; while the maxillary sends only a small branch to the orbit.
(1) Frontal, spUtting subsequently into supratrochlear and supraorbital, both passing out of the orbit. It is distributed to the corresponding upper eyehd, and the skin over the root of the nose, the forehead, and the hairy scalp as far back as the coronal suture on the same side. It also gives branches to the periosteum in this region, and to the frontal sinus.
(3) Naso-ciliary [n. naso-ciUaris] giving off — (a) a branch to the ciliary gangUon, constituting its long root ; (6) two or three long ciliary nerves; and (c) the injratrochlear, passing out of the orbit. The nerve then leaves the orbit as the anterior ethmoidal nerve [n. ethnioidaUs anterior], reentering the cranial cavity before being finally distributed to the nose. The infratroohlear branch [n. infratrochlearis], supplies the eyehds and skin of the side of the nose near the medial angle of the eye, the lacrimal sac, caruncle, and plica semilunaris. The anterior ethmoidal nerve, after its course in the cranial cavity, passes through an aperture in the front of the lamina cribrosa of the ethmoid bone, and is ultimately distributed to the nasal mucous membrane, and to the skin of the side and ridge of the nose near its tip.
2. The maxillary division of the fifth nerve gives a branch, called the zygomatic nerve, which passes into the orbit through the inferior orbital fissure, anastomoses with the lacrimal, and leaves the orbit in two divisions. These are distributed to the skin of the temple and of the prominent part of the cheek.
in this neighbourhood.
C. The sympathetic nerves of the orbit are mainly derived from the plexus on the internal carotid arterj'. With the exception of branches accompanying the ophthalmic artery, and of the distinct sympathetic root of the ciUary ganghon, they enter the orbit in the substance of
Lateral rectus muscle
the other nerve-cords. The connections between the ocular nerves and the carotid plexus are recognisable as fibres going to the oculomotor, abducens, and ophthalmic nerves; as a rule, the comparatively large twigs going to the abducens join it furthest back, and those to the oculomotor furthest forward. Sympathetic connections with the trochlear nerve are very doubtful. The special courses of the motor fibres to the dilatator pupillae muscle have already been described.
The ciliary ganglion is situated between the optic nerve and lateral rectus far back in the orbit. Its three roots — motor, sensory, and sympathetic — have been already mentioned. Anteriorly, it gives off three to six smaU trunks, which subdivide to form the short ciliary nerves [nn. cihares breves] about twenty in number, piercing the sclera around the optic nerve entrance.
The lymphatic system of the orbit. — Although there are no lymphatic vessels or glands in the orbit, the passage of lymph is nevertheless well provided for. We have already observed the lymph channels within, between, and outside the sheaths of the optic nerve, and have seen how these communicate anteriorly with the lymph channels of the eyeball, and posteriorly with the intracranial meningeal spaces. In addition, there are lymph-spaces around the blood-vessels, situated between the outer coat and the loose investment furnished by the muscle fascia. The nerves of the orbit (apart from the optic) are probably similarly surrounded by lymph-spaces. In the absence of lymphatic vessels it is difficult to trace the circulation thoroughly; much of the lymph from the orbital cavity is said to pass into the parotid nodes.
The cutaneous and conjunctival surfaces of the eyelids [palpebras] have already been examined (p. 1053), and the position of the tarsus has been indicated. We have now to ascertain the nature and relations of the tarsus, and describe the other tissues entering into the formation of the eyelids (fig. 821).
The skin here is thin, bearing fine hairs, and having small sebaceous and numerous small sweat-glands. Immediately beneath it is a loose subcutaneous tissue, destitute of fat, separating the skin from the palpebral part of the orbicularis muscle. The lid-fibres of this muscle arise from the medial palpebral ligament, and course over the whole upper and lower eyelids in a succession of arches, so as to meet again beyond the lateral angle; there they in part join one another, in part are inserted into the lateral palpebral raphe. The muscular fibres are arranged in loose bundles, with spaces between them occupied by connective tissue; in the upper lid these connective-tissue fibres may be traced upward and backward into the fibrous expansion of the tendon of the levator palpebree supe-
A central connective tissue separates the orbicularis muscle from the tarsus in the tarsal division of the lids. In the upper Ud this is to be regarded as mainly the anterior or fibrous expansion of the tendon of the levator palpebrse, which sends connective-tissue septa between the bundles of the overlying orbicularis (as just mentioned) going to the skin. In the orbital part of this hd the central connective tissue includes also the palpebral fascia, lying here immediately beneath the orbicularis muscle; but this soon thins off and fades into the more deeply placed levator expansion. This latter is strengthened by an extension of the sheath of the superior rectus, by which this muscle is enabled to influence the elevation of the Ud indirectl.y. In the lower lid the central connective tissue similarly consists of palpebral fascia, blended with a thin fibrous extension of the sheath of the inferior rectus.
upper lid.
The length of each tarsus is about twenty millimetres. Its breadth is greatest in the middle of the hd, and becomes gradually smaller toward 'each angle, where the tarsi are joined to the lateral raphe and medial palpebral ligament. The breadth of the upper tarsus (10 mm.) is about twice that of the lower. The thickness of each is greatest, and its texture closest, at the middle of its length, thinning off toward the angles of the eye and toward both borders. Into the superior anterior border of the upper tarsus the lower layer of the levator expansion is attached, consisting of smooth muscle-fibres constituting the superior tarsal muscle of Mtiller. In like manner, at the inferior border of the lower tarsus, bundles of smooth muscle-fibre are inserted (the inferior tarsal muscle of Miiller), developed in what has been regarded as part of the extension of the sheath of the inferior rectus.
The palpebral conjunctiva is firmly adherent to the posterior aspect of the tarsus; but in the orbital part of the lid loose subconjunctival tissue intervenes between it and Miiller's tarsal muscle. Lymphoid tissue occurs in the substance of the conjunctiva, especially in its orbital division. Near the upper fornix, the conjunctiva receives expansions of the tendon of the levator palpebrse and of the sheath of the superior rectus, and, at the lower fornix, of the sheath of the inferior rectus. The surface of the tarsal conjunctiva shows small elevations or papillae everywhere; but these are particularly well marked over the attached border of the tarsus.
Glands of the eyelids. — From its manner of formation the eyelid may be regarded as consisting of two thicknesses of skin, the posterior having been doubled back upon the anterior at the edge of the lid; thus the epidermis and corium of the skin proper are represented respectively by the conjunctiva (epithelium) and tarsus of the inner thickness. At the free border of the lid, accordingly, we find glands corresponding to the sebaceous and sweat-glands of the skin, viz., large sebaceous glands of the cilia (Zeiss's glands) and the ciliary glands of Moll, which are modified sweat-glands. Again, in the inner skin-thickness of the lid, the tarsal (Meibomian) glands are sebaceous.
Acino-tubular mucous glands occur at the attached border of the tarsus (Krause's or Waldeyer's glands), and similar glands also occur at the fornix, and are especially abundant near the outer angle of the upper lid, close to the efferent ducts of the lacrimal gland; from their structure and the character of their secretion, these acinous or acino-tubular glands have been termed by Henle 'accessory lacrimal glands.' Other simple tubular glands (Henle), formed merely by the depressions between the papiUae, are best developed in the medial and lateral fourths of the tarsal conjunctiva of both hds.
Blood-vessels. — The arteries run in the central connective tissue of the lids, mainly in the form of arches near the borders of the tarsus, from which twigs go to the different palpebral tissues. They are supplied by the lacrimal and palpebral branches of the ophthalmic, and by small branches derived from the temporal artery. The veins are more numerous and larger than the arteries, and form a close plexus beneath each fornix. They empty themselves into the veins of the face at the medial, and into the orbital veins at the lateral angle of the eye.
The lymphatic vessels of the lids are numerous, and are principally situated in the conjunctiva. Lymph-spaces also surround the follicles of the tarsal glands. The palpebral lymphatic vessels from the lateral three-fourths of the lid pass through the anterior auricular and parotid nodes; those from the medial fourth of the lower lid go to the facial and submaxillary lymphatic nodes.
Nerves. — (a) Sensory. The upper lid is chiefly supplied by branches of the supraorbital and supratrochlear nerves, the lower Ud by one or two branches of the infraoibital. At the medial angle the infratrochlear nerve also aids in the supply, and, at the lateral angle, the lacrimal, (b) Motor. The palpebral part of the orbicularis is suppKed by branches of the facial nerve, which mainly enter it near the lateral angle. The tarsal muscles are suppUed by the sympathetic nervous system.
The medial palpebral ligament has been referred to previously. Arising from the frontal process of the maxilla, it extends laterally over the front wall of the lacrimal sac, bends round the lateral wall of the sac, and then passes backward to the posterior crest on the lacrimal bone. It is thus U-shaped, having its limbs anterior and posterior, embracing the lacrimal sac; the anterior limb lies immediately beneath the skin, and is visible in the living. The palpebral fibres of the orbicularis are inserted into the anterior surface of both limbs, those attached to the posterior limb constituting the pars lacrimalis of the orbicularis palpebrarum (Horner's muscle). The lateral palpebral raphe is merely a stronger development of connective tissue in the orbicularis. Both ligaments are connected with the tarsi as already mentioned.
The tears are secreted by an acinous gland, and flow through fine ducts to the upper lateral part of the conjunctival sac, whence they pass over the cornea and are drained off through the puncta, pass along the canaliculi into the lacrimal sac, and ultimately down the naso-lacrimal duet to the inferior meatus of the nose.
The lacrimal gland is situated near the front of the lateral part of the roof of the orbit, lying in a depression in the orbital plate of the frontal bone. It consists of two very unequal parts, one placed above and the other beneath the tendinous expansion of the levator palpebree superioris, but small gaps in the expansion permit of connections between these two parts of the gland. The upper and larger subdivision (superior lacrimal gland) is a firm elongated body, about the size of a small almond; it has a greyish-red colour, and is made up of closely aggregated lobules. The upper surface (next the orbital roof) is convex, and its lower surface is slightly concave.
Anteriorly, the gland almost reaches the upper orbital margin, and it extends backward for approximately one-fourth the depth of the orbit, measuring about twelve mUlimetres in this direction. The lateral border of the gland descends to near the insertion of the fascial expansion of the lateral rectus, while its medial border almost reaches the lateral edge of the superior rectus; its transverse measurement is about twenty millimetres. It is enveloped in a capsule, which is slung by strong fibrous bands passing to its medial border from the orbital margin (suspensory hgament of the gland).
The lower subdivision of the gland (^inferior lacrimal gland) is composed of loosely applied lobules, and lies immediately over the lateral third of the upper conjunctival fornix, reaching lateralward as far as the lateral angle.
Each subdivision of the gland possesses several excretory ducts, which all open on the lateral part of the upper fornix conjunctivae, about four millimetres above the upper border of the tarsus. Those of the superior gland, three or four in number, pass betweefi the lobules of the lower gland; the most lateral duct is the largest, and opens at the level of the lateral angle of the eye. The ducts of the inferior gland in part discharge themselves into those of the upper, but there are also several fine ducts from this subdivision that run an independent course.
Near the medial angle are the two puncta lacrimalia, upper and lower, each situated at the summit of its papilla. The top of each papilla curves backward toward the conjunctival sac, so that the puncta are well adapted for their function of draining off any fluid collecting there.
The ductus (canaliculi) lacrimales extend from the puncta to the lacrimal sac. The lumen at the pmrctum is horizontally oval, from its lips being slightly compressed antero-posteriorly; the lumen of the lower punctum is somewhat larger than that of the upper. As the lower papilla is a little further from the medial angle of the eye than the upper, the corresponding canaliculus is longer.
courses more or less horizontally, converging slightly toward its fellow, and not infrequently joining it before opening into the sac. The calibre varies considerably in this course, being narrowest a short distance from the punctum, and widest at the bend, from which point it again narrows very gradually as it nears the sac.
The wall of the ductus consists mainly of elastic and white fibrous tissue, lined internally by epitheUum, and covered externally by striated muscle (part of the orbicularis). The musclefibres run parallel to the ductus in the horizontal part of its course; but they are placed, some in front and some behind, around the vertical part, acting here as a kind of sphincter. Just before their termination, the ducts pierce the periosteal thickening that constitutes the posterior limb of the medial palpebral ligament.
The lacrimal sac [saccus lacrimalis] lies in a depression in the bone at the medial angle of the orbit (the lacrimal fossa). It is vertically elongated, and narrows at its upper and lower ends; the upper extremity or fundus is closed, while the lower is continuous with the naso-lacrimal duct. Laterally, the sac is somewhat compressed, so that its antero-posterior is greater than its transverse diameter. The ducts, either separately or by a short common tube, open into a bulging on the lateral surface of the sac near the fundus.
As has previously been mentioned, the sac is surrounded by periosteum, but between this and the mucous membrane forming the true sac-wall there is a loose connective tissue, so that the cavity is capable of considerable distention. The relations of the medial palpebral Ligament have already been described; it is to be noted that the fundus of the sac extends above this ligament.
The naso-lacrimal duct [ductus naso-lacrimalis] reaches from the lower end of the sac to the top of the inferior meatus of the nose, opening into the latter just beneath the adherent border of the inferior nasal concha. Traced from above, its main direction is downward, but it has also a slight inclination backward and laterally. It lies in a bony canal, whose periosteum forms its outer covering. Between this and the mucous membrane of the duct there is a little intermediate tissue, in which run veins of considerable size connected with the plexus of the inferior concha. The duct does not usually open directly into the nasal cavity at the lower end of the bony canal, but pierces the nasal mucous membrane very obliquely, so that a flap [plica lacrimalis (Hasneri)] of mucous membrane covers the lower border of the opening in the bone, upon which flap the tears first trickle after escaping from the duct proper.
The sac and naso-lacrimal duct together constitute the lacrimal canal, lined throughout by a continuous mucous membrane. This membrane presents folds in some situations, especially near the opening of the canaliculi, at the junction of the sac and duct, and at the lower end of the duct. That at the top of the duct is the most important, as it sometimes interferes with the proper flow of tears out of the sac. The total length of the lacrimal canal is roughly twenty-four millimetres, half of this being sac, and half naso-lacrimal duct. If, however, we reckon as duct the obUque passage through the nasal mucous membrane, this measurement may occasionally be increased by eight or ten millimetres. The lacrimal sac, when distended, measures about six millimetres from before backward, by four millimetres transversely. The naso-lacrimal duct is practically circular, and has a diameter of about three millimetres, rather less at its junction with the sac, where we find the narrowest part of the whole lacrimal canal.
The eye is developed from the three sources involving two fundamental embryonic layers — the retina from a portion of the ectodermal wall of the forebrain on each side; the lens from the ectodermal surface epithelium; and the sclera, cornea (except epithelium) and chorioidal coat from the mesoderm which surrounds the former structures.
The process of development is, briefly, as follows: — The site of the eye is marked by a sUght depression on the surface of the forebrain on either side. There later an outgrowth occurs from the ventro-lateral aspect on each side of the forebrain, in the form of a hoUow vesicle, whose cavity is continuous with that of the forebrain. This outgrowth is termed the •primary optic vesicle [vesicula ophthalmicaj. The lateral surface of the vesicle comes into contact with the surface epithelium of the head and this epithelium becomes thickened at the area of contact. The superficial portion of the vesicle expands, while its connection with the brain remains slender; becoming depressed on the surface, it forms a cup-shaped hollow, the secondary optic vesicle or optic cup [caliculus ophthalmicus] whose wall is formed of two layers, an outer investing layer and an inner inverted one.
The chorioidal fissure is present almost from the first stages, as a cleft on the ventral aspect of both the distal portion of the vesicle, or cup, and of the stalk; and it is formed by an infolding of the surface into the cavity of the vesicle along a narrow linear area.
In this cleft are found vessels which pass to the hollow of the optic cup. The margins of the cleft meet and fuse, and enclose the vessels in the interior — hence the enclosure of the a. centralis retina within the optic nerve, and of the hyaloid artery in the interior of the vitreous. Should the margins of the cleft remain separate, the. condition of coloboma results.
From the optic cup is formed the whole of the retinal or nervous tunic. It will be noticed that this tunic is composed of two layers, with a narrow sUt-like interval between them, but that the layers are continuous with one another at the margin of the cup. This margin is afterward found, in the fully developed eye, at the pupillary margin of the iris. The outer investing layer forms the pigment layer, and the inner inverted layer gives rise to the other parts of the retina, viz., the pars optica, over the bottom of the cup, the pars ciliaris, in the ciliary region, and the pars iridica, near the margin of the original cup, including the dilatator and sphincter pupillae muscles of the iris.
The lens is formed as a hollow invagination from the surface epitheKum, which sinks into the hoUow of the optic cup. The margins meet and fuse, enclosing a cavity, and the lens mass sinking more deeply in, loses its connection with the surface, and a layer of mesoderm passes in between them.
The anlages of the lens and the primitive retina are at first in contact with one another. They graduaUy draw apart, and the intervening space is filled by the vitreous humour. The origin of the vitreous humour is not yet fully understood, but it appears to be developed from the adjacent ectoderm of the optic cup, and in part from the surrounding mesoderm.
The optic cup and the lens are surrounded by mesoderm and from it are formed the structures of the tunica vasculosa (middle coat) in its different parts, viz., chorioid, ciliary body and ins, and also the sclera and cornea (fibrous portion).
Bii I^^- f" n®''J5'" <'lia'»ber is formed by cleavage of the mesoderm, a space appearing in it, hUed with fluid. The mesoderm surrounding this space forms the endothehum Hning the anterior chamber. The mesoderm also forms a vascular covering for the front of the lens, termed the capsula vasculosa leniis, or pupillary membrane, which disappears from the surface of the lens in the later months of development.
The eyehds and conjunctiva are formed from the integumentary covering of the eye. 1 he former are mostly skin folds, which, at first separate, meet and fuse with one another along their margin. Subsequently they become undermined by the ingrowth of epithelium from a central horizontal sht, the rima palpebrarum ; the central part of the invading epithehum breaks down, and the free folds are formed.
The lacrimal canals and naso-lacrimal duct are formed by the growth of an epithelial band which passes through the mesoderm to the nasal cavity along the naso-lacrimal groove. This band loses its primitive connection with the groove, and is reunited to the lid margins by secondary epithelial bands which grow from the naso-lacrimal duct to the lid margin. Similarly a secondary connection is later made with the nasal cavity at the lower end of the duct. The position of the naso-lacrimal duct corresponds to the line of union of the nasal and maxillary processes; but the duct does not represent a portion of the cleft between these processes, and is formed secondarily between them.
Under the name of the ear [organon auditus] there is included a number of structures of which some, the ear proper, constitute the auditory mechanism — that is, an apparatus for the collection, transmission and reception of the waves of sound; while others — the semicircular ducts and associated structures — are concerned in receiving and transmitting impressions produced by movements of the head. These impressions constitute the basis of what may be termed the static or equilibratory sense, and afford data employed in estimating movements of the body in relation to surrounding objects.
The former of these, the ear proper, consists of three main parts, each possessing distinct structural and functional characters. The first portion, often known as the external ear, consists of a receptive organ placed upon the surface of the head, the auricle or pinna, and of a short tube, the external auditory meatus, which leads into the interior, and is closed at its deep end by the tympanic membrane.
The second portion, known as the middle ear, consists of the tympanic cavity, a small air-containing chamber in the petrous portion of the temporal bone, connected with the nasal part of the pharynx by a tube, the auditory (or Eustachian) tube. From the tympanic chamber a recess passes posteriorly and leads to a cavity in the mastoid portion of the temporal bone, the mastoid or tympanic antrum. A chain of three small bones transmits the sounds across the middle ear.
The third part, or internal ear which contains the essential sensory apparatus, lies within the complex cavities in the interior of the petrous temporal bone known as the osseous labyrinth. It consists of (1) the utricle and saccule, two small vesicular structures lying in the bony vestibule, and (2) the membranous semicircular ducts and (3) the membranous cochlea, which lie within the corresponding bony canals.
These structures are filled with fluid, the endolymph, and communicate with one another. They are largelj' separated from the bony walls by fluid, perilymph, and they are lined by sensory epithelium. Closely related to the epithelial sensory cells are found the terminal branches of the cochlear and vestibular nerves.
The auricle, or pinna, is an irregular oval plate-like structure which lies upon the lateral surface of the head. It presents a lateral and a medial surface. The lateral surface is irregularly concave (fig. 827). The deepest part of its concavity situated near the centre, is termed the concha, and it is partially divided by a prominent oblique ridge, the crus of the helix, into a superior part, the cymba conchae, and a large inferior part, the cavum conchae. The cavum conchse leads into the external auditory meatus, and is bounded ventrally by a prominent process, the tragus, which projects posteriorly over the entrance to the meatus. The tragus, is separated from the crus of the helix by a well-marked depression, the anterior incisure and has a small tubercle on it superiorly, the supratragic tubercle. Bounding the cavum conchte posteriorly and inferiorly is a projection, the antitragus, lying opposite, but inferior, to the tragus, and between the two is a deep notch, the intertragic notch [incisura intertragica]. A prominent semicircular
ridge, the anthelix, bounds the concha posteriorly and superiorly. Inferiorly it is separated from the antitragus by a slight depression, the posterior auricular sulcus. Superiorly the anthelix divides into two ridges, the crura of the anthelix, and between these is a shallow depression, the triangular fossa. The superior and dorsal margin of the auricle is inverted and forms a prominent rim, the helix, which
is continued anteriorly into the crus of the helix, and inferiorly into the lobule. An elongated depression, partly overlapped by the helix, termed the scapha (scaphoid fossa) separates the helix and the anthelix. Superiorly and dorsally the free margin of the helix frequently presents a slight projection, the auricular, tubercle (tubercle of Darwin).
Lamina tragi helix Cartilage of meatus
Upon the medial surface of the auricle the depressions of the lateral surface are represented by elevations, viz., the eminence of the concha, the eminence of the scapha, and the eminence of the triangular fossa, respectively; and the elevations by depressed areas, viz., the fossa of the anthelix, transverse sulcus of the anthelix.
and the sulcus of the crus of the helix. The attachment of approximately onethird of the medial surface covers up the two latter depressions. The cephalo-auricular angle, between the dorsal free part of the auricle and the side of the head, averages 20 to 30 degrees.
The features of the auricle just described are mainly produced by a plate of yellow elastic cartilage, the auricular cartilage. In addition to the elevations and depressions already noted, it presents the following additional features. Projecting anteriorly from the helix, near the crus is a small tubercle, spine of the helix (fig 828) ; while the posterior margin of the helix terminates in a pointed tail-like process, the cauda helicis which is separated inf eriorly from the antitragus by the deep antitrago-helicine fissure. Another deep fissure, the terminal notch [incisura terminalis auris], separates the cartilage of the auricle from that of the meatus, leaving only a narrow strip, the isthmus, connecting the two. The cartilage of the tragus, the lamina tragi, is separated from that of the auricle and is attached to the lateral margin of the cartilage of the meatus.
The auricle is covered on both its medial and lateral aspects by skin which closely follows the irregularities of the cartilage. Thus it is tightly bound to the perichondrium of the lateral surface by the subcutaneous areolar tissue, but much more loosely attached to the medial surface, and in the subcutaneous tissue there is little fat except in the lobule, which is made up almost entirely of fat and tough fibrous tissue. Hairs are abundant but rudimentary, except in the region of the tragus and antitragus, where they may be large and long, particularly in males and in the aged. Sebaceous glands are found on both surfaces, and are especially well developed in the concha and triangular fossa, but sudoriferous glands are few and scattered.
Ligaments and muscles. — The auricle is attached to the side of the head by the skin, by the continuity of its cartilage with that of the acoustic meatus, and by certain extrinsic ligamente and muscles. Three ligaments may be distinguished in the connective tissue: — The anterior ligament, stretching from the zygoma to the helix and tragus; the superior ligament, from the superior margin of the bony external acoustic meatus to the spine of the helix; and the posterior ligament, from the mastoid process to the eminence of the concha. There are also three extrinsic muscles, the anterior, superior, and posterior auricular (see p. 337, fig. 341). Six intrinsic muscles are distinguished. These are poorly marked in man and vary much in development. Upon the lateral surface (fig. 828) the helicis major stretches from the spine of the helix to the ventral superior margin of the helix; the helicis minor overlies the crus helicis; the tragicus runs vertically upon the tragus; and the antitragicus stretches from the antitragus to the cauda helicis. Upon the medial surface (fig. 828) the transversus auriculae stretches between the eminences of concha and scapha, and the obliquus between the eminences of the concha and the triangular fossa. Two small muscles occasionally present are the m. pyramidalis auriculse (Jungi) and the m. incisurse heUcis (Santorini).
The arteries are the auricular branch of the posterior auricular and the anterior auricular branches of the superficial temporal arteries. The veins are the anterior auricular vein of the posterior facial (temporal) and the auricular branches of the posterior auricular veins. The latter vessels sometimes join the transverse (lateral) sinus through the mastoid emissary vein. The lymphatics empty into the anterior, posterior and inferior auricular lymph-nodes. The sensory nerves of the auricle are the branches of the great auricular, small occipital (p. 977, fig. 753), and auriculo-temporal (p. 941, fig. 740). The muscles are suppUed by the posterior auricular branch of the facial (p. 944, fig. 740).
There are many variations in the size, shape, and conformation of the auricle and in the cephalo-auricular angle. These are associated not only with differences in sex, age, and race, but are also found in individuals of the same family.
THE EXTERNAL AUDITORY MEATUS
The external auditory (acoustic) meatus [meatus acusticus externus] extends medially and somewhat anteriorly and inf eriorly from the concha to the tympanic membrane (fig. 829). It is about twenty-five mm. (1 in.) long, and, owing to the obliquity of the tympanic membrane, its anterior and inferior wall is 5-6 mm.
longer than the posterior and superior. It consists of a lateral cartilaginous and a medial osseous portion. The canal describes an S-shaped curve in both horizontal and vertical directions. Near the auricular end it is convex anteriorly and inferiorly, while at the tympanic end the curve is reversed, and is concave in the same direction. The lumen is irregularly elliptical in outhne, the longer axis being vertical at the auricular, but nearly horizontal at its tympanic end. The meatus is constricted at about its centre, and also near the tympanum.
Osseous tuba auditiva
Relations. — The anterior loall is in relation with the condyle of the mandible medially, and with the parotid gland laterally; the inferior wall is closely bound to the parotid gland; and the 'posterior tuall of the bony part is separated by only a thin plate of bone from the mastoid cells. The superior loall is separated at its medial end by a thin plate of bone from the epitympanic recess, and laterallj' a thicker layer of bone separates it from the cranial cavity.
Structure of the meatus. — The walls of the meatus are formed laterally of fibro-cartilage and medially of bone, lined internally by skin. The cartilage is folded upon itself to form a groove, deficient in its dorsal part, where the edges of the cartilage are united by dense connective tissue. The cartilaginous groove is thus converted into a canal. Medially, the cartilage forms about one-third of the circumference; laterally, two-thirds. Two fissures (incisures of Santbrini) usually occur in its anterior wall (fig. 828). Laterally the cartilage is directly continuous with the cartilage of the auricle and medially it is firmly connected with the lateral lip of the osseous portion. The osseous portion, which forms slightly more than half the canal, is formed by the tympanic portion of the temporal bone; it is described in connection with that bone.
The skin of the meatus forms a continuous covering for the canal and tympanic membrane. It is thick in the cartilaginous, but very thin in the bony, part of the meatus, especially near the tympanic end, where it is tightly bound to the periosteum . In the cartilaginous meatus it contains numerous fine hairs and sebaceous glands, but neither hairs nor sebaceous glands are found in the bony meatus. Tubular ceruminous glands, which secrete the cerumen (ear wax) , form a nearly continuous layer throughout the cartilaginous, but occur on onlj- a small part of the posterior and superior wall of the bonj', meatus. The openings of their ducts appear as dark points to the naked eye (fig. 829).
The arteries are branches from the posterior auricular, superficial temporal, and deep auricular arteries (q.v.)- The veins and lymphatics connect with those of the auricle and empty similarly. The nerves are branches from the auriculo-temporal and the auricular ramus of the vagus.
2. THE MIDDLE EAR
Under the term middle ear there are included the tympanic cavity (tympanum), the tympanic antrum and the auditory (Eustachian) tube. These form a continuous irregular passage, filled with air, and located within and upon the surface of the temporal bone. The tympanum is shut off from the external ear
by the tympanic membrane; and from the chamber which forms the internal ear by the structures which fill in the cochlear and vestibular fenestra. It communicates with the pharynx by the auditory (Eustachian) tube. _ The structures of the middle ear are of importance, and the study is somewhat difficult, on account of the small size of the structures, the depth at which they lie, and the hard character of the surrounding bone.
The illustrations (figs. 829, 830, 831, 833, 834) will help to explain the text and should be constantly referred to. Figs. 830 and 831 are taken from frozen sections traversing the right ear in the coronal planes; while figs. 833, 834 represent dissections.
The Tympanic Membrane
The tympanic membrane [membrana tympani] (fig. 835) is elliptical in shape, its long axis nearly vertical, measuring 9 to 10 mm., its short axis, 8 to 9 mm. It slopes medially from the superior and posterior to the inferior and anterior
wall of the meatus, forming, as a rule, with the superior wall, an angle of 140 degrees. It varies, however, greatly in form, size, and obliquity. Viewed from the meatus, it appears as a semitransparent membrane, which sometimes has a reddish tinge. It is drawn medially and made funnel-shape by the manubrium of the malleus, but the walls of the funnel bulge toward the meatus (fig. 834) . The most depressed point at its centre, the umbo, is slightly inferior and posterior to the centre of the membrane, and corresponds to the tip of the manubrium (fig. 832). From it a whitish streak, the malleolar stria, caused by the manubrium shining through, passes superiorly toward the circumference. At the superior end of the stria is a slight projection, the malleolar prominence, formed by the lateral process of the malleus. From it two folds, the anterior and posterior Fig. 831. — Frozen Coronal Section op the Right Ear. (Somewhat Enlarged.)
plicffi, stretch to the extremities of the tympanic sulcus (fig. 832). The small triangular area of the membrane bounded by the plicae, is termed the pars flaccida (Shrapnell's membrane). It is thin and flaccid, and is attached directly to the petrous bone in the tympanic notch (notch of Rivinus). The larger part of the tympanic membrane, the pars tensa, is inferior to the plicae and is tightly stretched. Its thickened margin, the limbus, is attached by a fibro -cartilaginous annulus to the tympanic sulcus, and at the spines of the tympanic ring is continuous with the plicae.
Structure of the tympanic membrane. — The tympanic membrane is about .1 mm. thick, and consists of four layers. The lateral cutaneous layer, relatively thick, is a continuation of the skin lining the external auditory meatus. Next to it is a radiate fibrous layer, composed of connective tissue, the fibres of which are attached to the manubrium of the malleus and radiate from it. Medial to it is the circular fibrous layer, which has its fibres arranged concentrically and is esijecially thick at the cncumference. It is closely bound to the rachate layer. The mucous layer, which is a continuation of the mucosa of the tympanic cavity, covers the medial surface of the membrane smoothl}', except where the manubrium of the malleus causes a projection. The fibrous layers are attached to the fibro-cartilaginous ring and are not present in the pars flaccida.
The tympanic cavity [cavum tympani], as has been stated, is an air-space, lined with mucous membrane, situated between the external and the internal ear. It is of irregular outline, but, roughty, it is a slit-like cavity, lying in an oblique antero-posterior plane. Its transverse diameter measures only from 2-4 mm., while the vertical and antero-posterior diameters measure about 15 mm. (fig. 834).
It is narrowest at the centre, and wider superiorly than inferiorly. The bony walls have already been partly described with the temporal bone, and hence the description given here will refer to the appearance found in the fresh, or unmacerated condition.
It will be noticed (see fig. 829) that the floor of the space is on very much the same horizontal plane as the floor of the external meatus, and the lower margin of the tympanic membrane. The roof, on the other hand, lies at a much
higher level than the upper margin of that membrane. Hence the cavity may be divided into two regions, a loiver part, corresponding in extent to the tympanic membrane, and an upper, above the upper border of the membrane, known as the epitympanic recess. This division forms a definite chamber, and contains the head of the malleus and the body and short process of the incus. It is on the posterior part of this chamber that the communication with the tympanic antrum is found (fig. 835).
As the shape of the tympanum is irregular, its walls are not everywhere clearly marked off from one another, but there may be recognized (figs. 829 and 835) a roof, or tegmental wall, a floor, or jugular wall, a medial or labyrinthine wall and a lateral or membranous wall, an anterior or carotid, and a posterior or mastoid boundary or wall.
The roof, or tegmental wall, is formed by a portion of the tegmen tympani, a thin plate of bone which is continued backward to form the roof of the tympanic antrum. This plate is formed by the petrous part of the temporal bone, and at its lateral margin is the petro-squamous suture, where a slight deficiency in the roof may occur.
The floor, or jugular wall is very narrow transversely, and is in intimate relation to the internal jugular vein (fig. 831). As shown in fig. 833, the surface is frequently very irregular from stalactite-lilve projections between which are the tympanic cellulas (air cells), while near the back there is occasionally a marked projection corresponding externally to the root of the styloid process.
The posterior or mastoid wall presents at its lower part, many additional tympanic ceUulse, and higher up, an elevation, the pyramidal eminence, on whose apex is an aperture transmitting the tendon of the stapedius muscle. The fleshy beUy of that muscle is contained in a cavity in, the interior of the bony pyramid of the posterior wall. Lateral to this is an aperture, the aperiura tympanica canaliculm chorda, through which the chorda tympani nerve enters the tympanum, covered by a reflexion of the mucous membrane. Between this opening and the pyramid is a slight elevation; and above it is a fossa, termed the sinus posterior. Above this again is a recess, where the posterior ligament of the incus is attached, known as the fossa incudis. This portion of the posterior wall forms the boundary of the epitympanic recess. Here the ■cavity of the tympanum is continued with that of the antrum tympanicum, or mastoid antrum,
a large irregular space into which open the mastoid cells (see p. 1092). The boundaries of the orifice are formed above by the tegmen tympani, medially by the prominences of the lateral semicircular canal and facial nerve, and laterally by a plate of bone termed the scutum.
The carotid (anterior) wall presents superiorly the tensor tympani muscle in its canal, and at a lower level the opening of the tuba audiliva (Eustachian tube) (fig. 835). Inferiorly, a thin, bony wall, covered with tympanic cellulse and pierced by the carotico-tympanic nerves, separates the tympanic cavity from the carotid canal.
The membranous (lateral) wall is formed mainly by the tympanic membrane, with the small rim of bone to which it is attached, but superiorly the lateral wall of the epitympanic recess is formed by a plate of bone termed the scutum.
The labyrinth (medial) wall (fig. 833) presents inferiorly the promontory, produced by the first turn of the cochlea with the tympanic plexus (Jacobson's nerve) lodged in grooves upon its surface. Inferior and posterior to the promontory is a depression or fossula at the bottom of
Tympanic cellulae
which is the cochlear fenestra (fenestra rotunda), closed by the secondary tympanic membrane, and posterior to the promontory is a smooth projection, the subiculum of the promontory, which forms the inferior border of a rather deep depression known as the tympanic sinus. Anteriorly and superiorly is the cochleariform process, and superiorly and posteriorly are a depression or fossula leading to the vestibular fenestra (fenestra ovalis), which is closed by the base of the stapes, the prominence of the facial (Fallopian) canal, and the prominence of the lateral semicii'oular canal, the two latter being formed in the medial wall of the entrance to the mastoid antrum.
The tympanic mucous membrane forms a complete covering for the walls and contents of the tympanic cavity. It is continuous anteriorly with the mucosa of the tuba auditiva (Eustachian tube) and posteriorly with that of the tympanic (mastoid) antrum and mastoid cells. It is a thin, transparent, vascular membrane intimately united to the periosteum. As it passes from the walls to the contents of the tympanic cavity, besides covering the ligaments of the malleus and the incus and the tendons of the tensor tympani and stapedius muscles, it forms a number of special folds and pouches.
The anterior malleolar fold is reflected from the tympanic membrane over the anterior process and ligament of the malleus and the adjacent part of the chorda tympani, and the posterior malleolar fold stretching between the manubrium and the posterior tympanic wall, surrounds the lateral ligament of the malleus and the posterior part of the chorda tympani. Each of these folds presents inferiorly a concave free border, and between them and the tympanic membrane are two blind pouches, the anterior and posterior malleolar recesses or pouches
of Troltsch. Connected with the posterior recess is a third cul-de-sac, the superior recess of the tympanic membrane, or pouch of Prussak, situated between the pars flaccida of the tympanic membrane and the neck of the malleus. The floor of this recess is formed by the lateral process of the malleus, and is lower than its outlet; therefore, the recess may serve as a pocket in which pus or other fluid may accumulate. A somewhat variable fold of mucosa, the plica incudis, passes from the roof of the tympanic cavity to the body and short process of the incus. The body and short process of the incus, the head of the malleus, and this fold incompletelj separate off a lateral cupular portion of the epitympanic recess, and a stapedial fold stretches from the posterior wall of the tympanic cavity and surrounds the stapes, including the oburator membrane, which stretches between its crura. Other inconstant folds have been described. The mucosa of the typanic cavity, except over the tympanic membrane, promontory, and ossicles, is covered by a columnar ciliated epithelium.
stapedius
Bones. — The tympanic cavity contains three small movable bones, joined together and to the walls of the cavity, and having attached to them special muscles and ligaments. These auditory ossicles form a chain across the tympanic cavity connecting the tympanic membrane and the vestibular (oval) fenestra. They are the malleus, the incus, and the stapes, and are described in the section on Osteology on p. 79.
Articulations of the ossicles. — The manubrium and lateral process of the maUeus are imoedded in the tympanic membrane. The margin of the irregularly elliptical articular surface bn the posterior side of the head of the malleus is bound to the body of the incus by a thin capsular ligament, forming a diarthrodial joint, the incudo-malleolar articulation. From the inner surface of the capsular ligament, a wedge-shaped rim projects into the joint cavity and incompletely divides it. The long crus of the incus lies parallel to the manubrium of the malleus and on its superior and medial aspect (figs. 833 and 835). It ends in the lenticular process. The convex extremity of this fits into the concavity on the head of the stapes, to form a diarthrodial joint, the incudo-stapedial articulation. From its articulation with the incus, the stapes passes almost horizontally across the tympanic cavity to its junction with the medial wall. The cartilage-covered edge of the base is bound to the cartilage-covered rim of the vestibular (oval) fenestra by the annular ligament of the base of the stapes, thus forming the tympano-stapedial syndesmosis.
Ligaments of the ossicles. — In addition to the attachment of the manubrium of the malleus and the base of the stapes to the walls of the tympanic cavity, the bones have additional ligamentous attachments. The superior malleolar liga-
ment runs almost vertically from the superior wall of the epitympanic recess to the head of the malleus (fig. 834) . The anterior malleolar ligament extends from the angular spine of the sphenoid bone through the petro-tympanic (Glaserian) fissure to the anterior or long process of the malleus, which it surrounds, and is inserted with it into the neck of the malleus. The lateral malleolar ligament is short and thick, and runs from the margins of the tympanic notch (notch of Rivinus) to the neck of the malleus (fig. 834) . The posterior ligament of the incus passes from the fossa on the posterior tympanic wall to the crus brevis of the incus (fig. 835) . The superior ligament of the incus is little more than mucous membrane; it runs from the tympanic roof to the body of the incus.
Muscles of the ossicles. — Each of the muscles of the ossicles is contained in a bony canal. The tensor tympani is a pinniform muscle about 2 cm. long. It arises from the cartilaginous part of the tuba auditiva (Eustachian tube), from the
membrana tympani
adjacent part of the great wing of the sphenoid, and from the bony walls of the semicanal which encloses it. It ends in a round tendon which turns almost at right angles over the cochleariform process and passes laterally across the tympanic cavity to be attached to the manubrium of the malleus near the neck. It draws the manubrium medially and tightens the tympanic membrane, and is supplied by the motor division of the trigeminal cranial nerve, through the tensor tympani branch from the otic ganglion. The stapedius arises in the interior of the hollow pyramidal eminence. The tendon escapes through the openings at the apex and then turns inferiorly and is inserted on the posterior surface of the neck of the stapes. It draws laterally the ventral border of the base of the stapes and is supplied by the facial nerve.
Vessels and nerves. — The arteries of the tympanic cavity are the anterior tympanic from the internal maxillary artery (fig. 451), the stylo-mastoid from the posterior auricular artery, the superficial petrosal from the middle meningeal artery, the inferior-tympanic from the ascending pharyngeal (fig. 446), and the carotio-tympanic branch from the internal carotid. The veins empty into the superior petrosal sinus and into the posterior facial (temporomaxillary vein). The nerves are the tympanic plexus formed by the tympanic branch of the glosso-pharyngeal (p. 951), and the inferior and superior carotico-tympanic nerves which join the internal carotid plexus of the sympathetic (p. 960). The small superficial petrosal nerve takes its origin from the tympanic plexus, and the chorda tympani crosses the t)"mpanic cavity from the posterior to the anterior wall (p. 948, figs, 738 and 835).
The aperture {aditus) in the upper part of the posterior wall of the tympanum leads into the chamber termed the antrum tympanicum. This is a comparatively large cavity, of irregular form, lying mainly behind but also somewhat above and lateral to the tympanum, and extends to the medial end of the external auditory meatus. It is lined by mucous membrane, continuous with that of the tympanic cavity, and into it open the mastoid cells (cellulse mastoidese). These cells are small, irregular cavities in the interior of the mastoid process and they communicate with one another freely. They vary exceedingly in their size and asrangement.
The antrum tympanicum has a roof, formed by the tegmen tympani, a posterior wall, separating it from the bend of the transverse sinus, a lateral wall, lying about 10 mm. from the surface of the head, a inedial wall, and an anterior wall (see also p. 78).
The auditory tube [tuba auditiva] (Eustachian tube) (fig. 829) extends from the carotid (anterior) wall of the tympanic cavity inferiorly, medially, and anteriorly to the pharynx. It is about 37 mm. (1.5 in.) long. In the lateral one-third of its length it has a bony wall, while in the medial two-thirds this wall is cartilaginous. The osseous part (see p. 74) begins at the tympanic ostium on the anterior wall of the tympanic cavity. It is in relation medially and inferiorly with the carotid canal, and gradually contracts to its irregular medial extremity, which is the narrowest point in the tube, and is termed the isthmus. The cartilaginous part is firmly attached to the osseous and hes in a sulcus at the base of the angular spine of the sphenoid bone. It gradually dilates in its passage to the lateral wall of the pharynx, where its opening, pharyngeal sotium, is just posterior to the inferior nasal concha (turbinated bone). The walls of the cartilaginous part are formed by a cartilaginous plate which is folded so as to form a trough-like structure, consisting of a medial and a lateral lamina, completed inferiorly by a membranous lamina formed of connective tissue.
A small portion of the lumen in the superior part of the cartilaginous tube remains permanently open; elsewhere the walls are in contact, except during deglutition, when they are opened by the tensor veli palatini muscles. The mucosa of the osseous part is thin, and firmly attached to the bony wall, but in the cartilaginous part it becomes thicker, looser, and folded, and contains mucous glands, especially near the pharynx, where there is also some adenoid tissue.
The internal ear [auris interna] is the essential part of the organ of hearing. It consists of a cavity, the osseous labyrinth, contained within the petrous portion of the temporal bone, and enclosing a membranous labyrinth. The osseous labyrinth is divided into cochlea, vestibule, and semicircular canals (seep. 80), and the accompanying figures (338-838 )show their position and relations.
from the ventral and inferior.
It will further be noticed that the bony wall of this vestibule shows depressions and ridges on its interior, which are associated with parts of the membranous labyrinth, viz., an upper recess for the utricle (fovea hemielliptica) and a lower recess for the saccule (foyea hemispherica). There are openings in the bony wall for the entrance of nerves to the different parts of the membranous labyrinth, and for the transmission of the ductus endolymphaticus, as well as the small openings of the semicircular canals (ducts) and the opening of the cochlear canal (or duct).
The membranous labyrinth, in which the auditory (acoustic) nerves (cochlear and vestibular) end, lies within the osseous labyrinth, the form of which it more or less closely resembles. Thus the membranous semicircular ducts lie within the bony semicircular canals, the membranous cochlear duct within the bony cochlea; while the vestibule contains two small membranous sacs, the utricle and saccule, with their connections. The membranous structures are much smaller in diameter than the osseous, and are partially separated from the bone by an endothelial-Hned space which is filled with a fluid, the perilymph. The
membranes are in contact, however, with the bony wall along their convex margin, and the utricle, saccule and cochlear canals are in contact with the bony walls over the areas where the nerves enter them. The fluid which fills the membranous labyrinth is termed the endolymph.
Commencement of first turn of the cochlea
The utricle is an oval tubular sac, whose rounded end lies in the superior and dorsal portion of the vestibule. It is here tightly bound to the elliptic recess (fovea hemielliptica) by connective tissue and by the entrance of the filaments of the utricular division of the vestibular nerve as they pass from the superior
canaliculus
macula cribrosa to the wall of the utricle. In the anterior part of the interior of the utricle, an oval, whitish, thickened area, macula acustica utriculi, marks the terminal distribution of the nerve, and posteriorly the utricle is joined by the orifices of the semicircular ducts.
Modiolus
The saccule is a flattened, oval sac, smaller than the utricle, and situated in the anterior and inferior part of the vestibule. It is bound to the spherical recess (fovea hemisphserica) by connective tissue and by the saccular division of the
vestibular nerve, filaments of which extend from the middle macula cribrosa to the anterior and medial wall of the saccule, to be distributed over a thickened area, macula acustica sacculi. Anteriorly and inferiorly the saccule gradually passes into a short canal, the ductus reuniens, which connects it with the cochlear duct, and posteriorly the very small endolymphatic duct is attached (fig. 839).
Ductus endolymphaticus
This extends through the aquseductus vestibuli to the posterior surface of the petrous portion of the temporal bone, where it ends in a dilated blind pouch, the endolymphatic sac, situated just beneath the dura. Just beyond the saccule, the endolymphatic duct is joined at an acute angle by a short canal of minute calibre, the utriculo-saccular duct, which opens into the utricle through its anterior medial wall and, with the endolymphatic duct, connects it with the saccule.
Posterior ampuUary nerve
The semicircular ducts (membranous semicircular canals) are situated within the osseous semicircular canals and are, therefore, known as the lateral, superior, and posterior semicircular ducts. They connect with the utricle by five openings, the posterior and superior ducts uniting to form a common crus before their
termination. Each duct is less than a third of the diameter of the bony canal, from which it is separated by a large perilymphatic space, except along the greater cm*vature, where it is attached. The ducts are dilated in the bony
ampullse, producing the lateral, superior, and posterior membranous ampullae, and on the attached surface of each of these there is a transverse groove, the ampullary sulcus, for the ampullary division of the vestibular nerve, and corresponding to the sulcus a ridge, the ampullary crista, projects into the interior.
The cochlear duct (membranous cochlea or scala media) begins within the cochlear recess of the vestibule in a blind pouch, the vestibular caecum, and traversing the spiral canal of the cochlea, ends just beyond the hamulus of the lamina spiralis in a second blind pouch, the cupular caecum. Close to the vestibular caecum it is joined to the saccule by the ductus reuniens. It is lined throughout by epithelium and is somewhat triangular in cross-section. Its floor is formed by thickened periosteum over part of the osseous lamina spiralis and by a fibrous membrane, the lamina basilaris, which stretches from the free border of the lamina spiralis to a thickening of the periosteum, the spiral ligament of the cochlea, on the peripheral wall.
The epithelium of this floor is greatly modified, forming the spiral organ (organ of Corti) in which the fibres of the cochlear nerve terminate. The periplieral wall is formed by the thickened periosteum upon the peripheral wall of the cochlear canal, while the third waU is
Vesicle.
fomed by a thin vestibular membrane (membrane of Reissner) which passes from the periphera wall to the osseous lamina spiralis near its free margin, forming with the lamina spiralis an angle Ff 45 degrees. The cochlear duct and the osseous spiral lamina divide the cochlear spiral canal into two parts, one next to the basilar membrane, the scala tympani, and one next to the vestibular membrane, the scala vestibuli. The scala tympani unites with the scala vestibuli at the helicotrema, and from the scala tympani a minute canal, the perilymphatic duct, passes through the cochlear canaliculus and connects with the subarachnoid space. A thin fibrous layer, the secondary tympanic membrane, closes the cochlear fenestra (fenestra rotunda) and thus separates the scala tympani from the tympanic cavity, and the vestibular perilymphatic space (scala vestibuli) is separated from the tympanic cavity by the base of the stapes in the vestibular fenestra (fenestra ovalis).
Vessels and nerves. — The internal auditory artery , fig. 514), a branch of the basilar artery, accompanies the cochlear and vestibular nerve. It supplies the vestibule, semicircular canals, and cochlea, and their membranous contents. The blood is returned by the internal auditory vein into the inferior petrosal sinus, and by small veins which pass through the cochlear and vestibular aqueducts to the inferior and superior petrosal sinuses. The acoustic nerve (p. 949, figs. 841 and 842) consists of a vestibular and a cochlear division. The membranous ampuUse of the semicircular ducts and the acoustic maculae of the utricle and saccule are supplied by the vestibular nerve. The spiral organ (organ of Corti) in the cochlear duct is supphed by the cochlear nerve.
The external and middle ears have a common origin quite distinct frorn that which gives rise to the internal ears, and are to be regarded as portions of the branchial arch apparatus secondarily adapted to auditory purposes.
The sensory epithelium lining the internal ear is derived from the otic vesicle, a structure formed from the surface epithelium of the head, while the membrane and bones surrounding it are formed from the mesoderm which surrounds the vesicle.
Internal ear. — The process of development is as follows (fig. 843-845) : — By invagination from the surface, an epithelial-lined vesicle, termed the primitive otocyst or otic vesicle, is formed dorsal to the extremity of the second branchial cleft. It is at first merely a pit on the surface, but eventually it loses its connection with the surface epithelium and sinks into the interior. It then undergoes the alterations in shape and form shown in the accompanying fig. 845. The vesicle is at first somewhat oval, and a small hollow stalk arises from it, the recess of the labyrinth, which forms the ductus endolymphaticus in the adult. The ventral and dorsal portions of the cyst become enlarged. From the former two hoUow plate-like projections arise, one placed vertically, the other horizontally, and along the free margins of these plates are formed the semicircular ducts, the superior and posterior from the vertical, and the lateral duct from the horizontal one. The central part of each plate becomes peforated, and the periphery is thus altered to the characteristic loop form of the adult semicircular ducts. The portion of the vesicle lying between the dorsal and ventral enlargements forms the primitive atrium. It becomes divided into two chambers, an upper dorsal connected with the semicircular ducts, forming the utricle, and an inferior ventral, the saccule, which is connected with that portion of the ventral expansion from which the cochlea is formed. The recess of the labyrinth retains its connection with the cavity of the vesicle at the narrow stalk connecting utricle and saccule, (fig. 845). The cochlea is formed by an outgrowth from the saccule, at first straight, and later coiled in the fashion formed in the adult.
Cochlea
External and middle ear. — The external auditory meatus is formed from the dorsal part of the first (external branchial) pouch, and the tympanic membrane from the membrane which forms the floor of that pocket and separates it from the corresponding pharyngeal (internal) pouch. Its outer surface is thus formed from ectoderm and the inner from endoderm. The internal (pharyngeal) groove gives origin to the tympanic cavity and tuba auditiva, the margins of the groove uniting.
The auricle is formed from nodular thickening of the tissue bounding the outer end of the first branchial cleft. Three nodules are formed on the first (mandibular) and three on the second (hyoid) arch. Behind the latter, the free margin of the auricle is formed by a folding off of the integument. Later an additional tubercle is formed dorsally between the two sets of nodules. From the mandibular nodules are formed mainly the tragus and the crus of the helix — from the hyoid tubercles the scaphoid fossa, antitragus and the crus of the anthchx.
The auditory ossicles, and their muscles are formed from the neighbouring arches, the malleus and incus, together with the tensor tympani, being derived from the first arch, while the stapes and stapedius probably are derived from the second arch.
The tympanic cavity is at first quite small, but later increases greatly, partly by the condensation bf the loose areolar tissue which underlies its mucous membrane, the auditory ossicles and their muscles being thus apparently brought within the cavity, and partty by the absorption of the neighbouring bone. By this latter process the antrum and the tympanic and mastoid cells are formed, all these depressions or cavities being lined by mucous membrane continuous with that of the tj'mpanic cavit}'.
1. The external auditory meatus is very short, since the bony portion is undeveloped, and is represented only by the tympanic ring. As a result of this, the tympanic membrane is placed on a level with the surface of the head, and looks very much downward.
tympanum. Its lateral wall is only about 1 mm. in thickness.
3. The mastoid process is not developed, and hence the stylomastoid foramen opens on the surface behind the lower part of the tympanic ring. The exit of the facial nerve is therefore much more upon the surface, and higher up than in the adult.
References for the Special Sense Organs. — For the development of the various sense organs, see article by Keibel in Keibel and Mall's Human Embryology, vol. 2. A. Visual. Graefe-Saemisch, Handbuch d. ges. Augenheilkunde; Salzmann, Anat. u. Histol. d. Augapfels, 1912; various papers in Archiv f. Ophthalmologic; (Anterior chamber, etc.) Henderson, Ophthalmic Review, 1910-11; {Optic disc) Johnson, Phil. Trans. Royal Soc. B. vol. 194; B. Auditory. Gray, Labyrinth of Mammals, 1910; (Tectorial membrane, etc.) Hardesty, Amer. Jour. Anat., vol. 8; (Auditory nerve, comparative) Holmes, Trans. Royal Irish Acad., vol. 32, ser. B; (Experimental embryology) Lewis, Amer. Jour. Anat., vols. 3, 7; C. Olfactory. Read, Amer. Jour. Anat., vol. 8. D. Taste. Von Ebner, in Koelliker's Handbuch d. Gewebelehre; Graberg, Anat. Hefte, Bd. 12.
IN order to furnish the living protoplasm with the materials necessary for energy, growth and repair, a constant supply of food must be provided. Most foods must be rendered soluble, and must undergo certain preliminary chemical changes, in order to render them suitable for absorption and assimilation by the cells of the body. For this preparation of the food-supply, the digestive system [apparatus digestorius] is provided, which includes the alimentary canal and certain accessory glands (salivary glands, liver and pancreas) . The alimentary canal is divided into a number of successive segments, varying in size and structure according to their function. These segments (fig. 846) include the mouth, pharynx, oesophagus, stomach, small and large intestines.
Typical structure. — The most important layer of the tubular alimentary canal is the inner mucous memhrane [tunica mucosa]. From its epithelial lining, the various digestive glands are derived, and through it the process of absorption takes place. The epithelium is supported by a fibrous tunic [lamina propria mucosa;] beneath which is a thin layer of smooth muscle [lamina muscularis mucosae]. The layer next in importance is the muscular coat [tunica muscularis] which propels the contents along the canal. It is typically composed of two layers of smooth (involuntary) muscle, the inner circular and the outer longitudinal in arrangement. Between the mucosa and the muscularis is a loose, fibrous submucous layer [tela submucosal, which allows the folds in the mucosa to spread out when the canal is distended. Finally, there is an outer fibrous coat [tunica fibrosa], which in the abdominal cavity becomes the smooth serous coat [tunica serosa], or visceral layer of the peritoneum, which eliminates friction during movements. The variations in the structure of the aUmentary canal in different regions are due chiefly to differences in the mucosa.
Glands. — Since the glands form an important part of the digestive system, the classification of glands in general will be discussed briefiy. A gland may be somewhat loosely defined as an organ which elaborates a definite substance which is either a waste product to be eliminated (excreted), or a secretion to be further utilized by the organism. Glands may be divided into (a) ductless glands (e. g., spleen, thyreoid gland), which pour their secretions directly into the blood or lymph; and (b) glands with ducts, which open upon an epithelial surface. Some organs, however, belong in both classes (e. g., liver, pancreas).
The glands with ducts (the so-called true' glands) are always derived from an epithelial surface and may be further subdivided upon the basis of either (1) form or (2) cell-structure. According to form, glands are classified as either <?<iwtor or saccular (alveolar, acinous). Each of these may be either simple or compound (branched). The compound saccular form is often called racemose. Moreover, intermediate forms (tubulo-racemose) occur.
According to cell-structure and character of secretion, glands are divided into mucous and serous types. In the mucous type, the ceUs appear larger and fighter (fig. 867) when swollen with mucus which is secreted for purposes of lubrication. The goblet^ceUs of the intestine represent imicellular glands of this type. In the serous (or albuminous) type of glands, the cells usually appear somewhat smaller and more deeply stained, with numerous zymogen granules (fig. 867). The secretion is a watery, albuminous fluid, which contains the digestive enzymes. There occurs also a mixed type, with separate mucous and serous saccules, or both types of cells may occur in the same saccule (the serous cells as 'demilunes' or 'crescents' (fig. 867). In aU cases, the epithelial gland ceUs are supported by a fibrous connective-tissue stroma, which provides a rich vascular and nerve-supply.
Morphology. — The alimentary canal in comparative anatomy is divided into the head-gut (mouth and pharynx), fore-gut (cesophagus and stomach), mid-gut (smaU intestine), and hindgut (large intestine). Embryologically, the mid-gut corresponds roughly to the portion of the archenteron attached to the yolk-sac, the portions of the archenteron anterior and posterior to the yolk-sac being designated as fore-gut and hind-gut respectively. (See Section I, Morphogenesis.) The lining epithelium of the alimentarj' tract is endodermal, excepting the anal canal and the mouth cavity, which are lined by invaginations of the ectoderm.
In the region of the mouth and pharynx, the digestive and respiratory systems are closely related in position, structure, function and origin. Morphologically, the head-gut represents a primitive aUmentary-respiratory apparatus.
THE MOUTH
The oral cavity [cavum oris] represents the first segment of the alimentary canal. Its walls are exceedingly specialised in structm-e, corresponding to its manifold functions (mastication, insalivation, taste, speech, etc.).
Boundaries. — The oral cavity communicates anteriorly with the exterior through the transverse oral fissure [rima oris], and posteriorly with the pharynx through the isthmus of the fauces [isthmus faucium]. The anterolateral walls are formed by the flexible lips and cheeks. The roof is chiefly immovable and is
formed by the lower jaw and the tongue.
Subdivisions. — The oral cavity is subdivided by the alveolar and dental arches into an inner cavity, the oral cavity proper [cavum oris proprium], and an outer vestibule [veigtibulum oris] adjacent to the lips and cheeks (fig. 848). When the upper and the lower teeth are in apposition, the vestibule communicates
with the oral cavity proper (aside from the small interdental spaces) only through a space behind the last molar teeth on each side. Opening into the oral cavity are certain accessory glands, the salivary glands.
Structure. — Of the typical layers of the alimentary canal, only the mucous membrane can be recognised as a continuous layer in the mouth cavity. Even this is greatly modified and in structure somewhat resembles the skin, from which it is derived and with which it is continuous
Lower Up
at the rima oris. The submucosa is a strong fibrous layer connecting the mucosa with adjacent structures, and lodging numerous racemose mucous glands. The muscles in the walls of the mouth cavity are not homologous with the typical muscularis of the alimentary canal. The outer fibrous tunic is also wanting.
DIGESTIVE SYSTEM
The development of the oral cavity. — As stated in the section on Morphogenesis, the oral cavity has its origin in a depression, the oral fossa, situated between the ventrally bent, developing head and the region occupied by the developing heart. This fossa is bounded anteriorly by the fronto-nasal process, and laterally by the maxillary and mandibular processes, portions of the first branchial arches. The fossa is lined by ectoderm. Its floor is in apposition with the cephalic end of the archenteron, lined by entoderm, the ectoderm of the oral fossa and the entoderm of the archenteron being in immediate contact and forming the pharyngeal membrane. The oral fossa deepens with further development, and becomes the oral sinus. The pharjmgeal membrane becomes perforated in embryos about 2 mm. in length and disappears, leaving a free communication between the oral sinus and archenteron. On each side of the developing head and in a latero-ventral position there is early developed an area of thickened ectoderm, known as the nasal area. These areas soon develop into depressions, the nasal fossae, and assume a position, one on either side of the fronto-nasal process; on each side of the frontonasal process there is developed a prominent protuberance, the globular process, each process forming the median wall of a nasal fossa. The lateral wall of each nasal fossa also thickens to form the lateral nasal process. With the further development, the ventral portion of each lateral nasal process fuses with the corresponding globular process, the maxillary processes also uniting with the globular processes, in this way separating the nasal fossae from the oral sinus. With the further growth toward the median hne of the maxiUary processes the fronto-nasal process becomes narrower, ultimately forming the nasal septum and a small median portion of the upper jaw, the remainder of the upper jaw being formed by the maxillary processes, and the lower jaw having its origin in the mandibular processes.
muscle muscle
Variations. — The mouth is rarely absent, due to failure of the stomatodeal invagination, or imperforate, due to atresia of the pharyngeal membrane. Other variations wiU be mentioned in connection with the various mouth organs.
Comparative. — The phylogenetic origin of the mouth cavity from the integument is indicated not only by the ectodermal origin of its lining epithelium, but by its general structure and its appendages. Among the latter may be noted the teeth (representing modified dermal papillae), sebaceous glands, and (in some rodents) even hairs in the mucosa lining pouches in the cheeks.
THE LIPS AND CHEEKS
The lips [labia oris] form the anterior wall of the mouth cavity. The lower Up [labium inferius] is marked off from the chin by the sulcus mentolabialis. The upper lip [labium superius] extends upward to the nose medially and the sulcus nasolabialis laterally. The philtruni is a median groove on the upper lip extending from the septum of the nose above to the labial tubercle [tuberculum labii superioris] below, at the middle of the rima oris. On each side of the rima oris the upper and the lower lips are continuous at the angle of the mouth [angulus oris], which is usually opposite the first premolar teeth. Laterally, the lips are
cavity.
In structure, the lips (fig. 849) consist essentially in a middle layer of cross-striated muscle (orbicularis oris) covered externally by skin which is continuous through the rima oris with the mucosa forming the inner layer of the hps. The mucosa lines the vestibulum oris and is reflected upon the gums above and below. In the median line above and below, there extends fi-om the lip to the gum a small fold of the mucosa [frenulum labii superioris vel inferioris]. The structure of the cheeks (figs. 847, 864) is similar to that of the lips but somewhat more complicated.
tooth.
Glands. — The skin of the lips and cheeks is well supplied with the usual sudoriparous and sebaceous glands. The mucosa likewise presents two kinds of glands, the sebaceous and the mucous glands. The sebaceous glands are relatively few in number and variable, being present in about 30 per cent, of cases in the adult (Stieda). They are similar in structure to those of
cheek opposite the teeth.
The mucous glands are much more numerous and constantly present (figs. 850, 851). They are all of the racemose type. They are variable but small in size, and closely packed together in the submucosa of the lips [glandulte labiales], where they may easily be felt. Those of the cheeks [gl. buccales] are less numerous. A few of them especially in the region of the molar
this muscle near the parotid duct to open on the surface of the mucosa.
Vessels and nerves. — The mucosa of the lips and cheeks has a characteristic reddish hue, on account of the numerous blood-vessels which are visible through the thick but transparent stratified squamous epithelium (figs. 849, 851) The numerous papillae of the lamina propria are highly vascular. The hlood-supply of the lips and cheeks is derived chiefly from the labial (coronary) and buccal arteries. The rich nerve-supply (sensory) is from the infra-orbital, mental and buccal branches of the fifth. The lips are especially sensitive near the rima oris.
Development. — During the second month in the human embryo, ledges of epithelium grow into the substance of the mandibular and the fused fronto-nasal and maxillary processes. These ledges develop into grooves which separate the upper and the lower lips from the upper and the lower jaws, the grooves forming the oral vestibule.
The philtrum and labial tubercle are said to correspond to the lower part of the frontonasal process. A failure of union between the globular and the maxillary processes presents an arrest of development resulting in the malformation known as "hare-lip." ■
In the late fcetus and newborn, the red portion of the lips consists of an external smooth pars glabra, and an inner zone, pars villosa, which is covered with numerous villus-like projections. The largest of these reach a length of 1 mm. They also extend backward in an irregular band along the mucosa of the cheek. They disappear during the first few weeks of postnatal life.
The sebaceous glands of the mucosa are said not to appear until about the age of puberty.
Variations. — As is well known, the lips and cheeks are exceedingly variable in shape, size and structure in different individuals. There are also characteristic differences according to race and sex in the form and structure of the lips, rima oris, beard, etc. The "harcrlip" malformation was mentioned above.
tions, the anterior or hard palate and the posterior or soft palate.
The hard palate [palatum durum] (figs. 848, 852) is continuous in front and laterally with the alveolar processes of the upper jaw, and gives attachment posteriorly to the soft palate. It separates the mouth from the nasal cavity. It is supported by the palatine process of the maxilla and the horizontal part of the palate bone. The oral surface is concave from side to side, and also from before backward. It is covered by a thick, somewhat pale mucosa, which is firmly adherent to the periosteum through the submucosa. The submucosa contains numerous mucous glands [gl. palatinse] (fig. 852), similar to those of the lips.
In the median line of the hard palate is a line or ridge, the raphe (fig. 852) terminating anteriorly in the small incisive papilla, which corresponds in position to the bony incisive foramen. Anteriorly there occur four to six more or less distinct transverse ridges [plicae palatinse transversse]. Near the posterior margin of the hard palate there is on each side of the raphe a small pit (fig. 852), the foveola palatina, which is variable and inconstant.
The soft palate [palatum moUe] (figs. 848, 892) separates the posterior portion of the mouth cavity from the nasal part of the pharynx. It is attached to the hard palate anteriorly and to the pharyngeal wall laterally. The posterior portion or velum projects backward and downward into the pharynx. Its free margin presents a median conical projection, the uvula, and splits laterally on each side to form two folds, the palatine arches, between which is located the palatine tonsil (fig. 852). The palatine arches and tonsil will be described later in connection with the pharynx.
Structure. — The soft palate is a fold of mucous membrane enclosing a fibrous aponeurosis, muscles, vessels, and nerves. It is marked in the middle line by a raphe indicating the hue of junction of the two halves from which it was formed.
The posterior layer of the mucous fold which is directed toward the cavity of the pharynx is continuous with the na.sal mucous membrane; the anterior layer lies in the posterior boundary of the mouth and is continuous with the mucous membrane of the hard palate. The structure of the mucosa is very similar to that of the lips (fig. 849). Mucous glands are numerous in both layers, but more especially in the anterior, and make up a large portion of the mucosa and submucosa (figs. 851, 852).
The aponeurosis is attached above to the posterior margin of the hard palate; laterally it is continuous with the aponem-otic layer of the pharyngeal wall; below, toward the lower margin of the velum, it gradually disappears. It gives attachment to fibres of the levator veli palatini and the jjharyngo-palatinus (palato-pharyngeus) and to the tendon of the tensor veli palatini.
M. pharyngopalatinus
(1) Ascending palatine of external maxillary (facial); (2) pharyngeal branches of ascending pharyngeal; (3) twigs from descending palatine of internal maxillary, which enter the smaller palatine canals, are distributed to the soft palate and tonsils, and communicate with the ascending palatine of the external maxillary (facial) artery; (4) lingual artery, by twigs from the dorsal branch.
The sensory nerves to the'palate are derived chiefly from the fifth' through che sphenopalatine ganglion. The hard palate is supplied by the nasopalatine and anterior palatine branches; the soft palate chiefly by the median and posterior palatine branches. The motor nerves will be mentioned later in connection witli the muscles.
The development of the palate. — The hard and soft palates arise (fig. 853) in two ridges of tissue, designated the palate shelves, which develop on the inner surfaces of the maxillary processes. These shelves grow toward the median line, and at the beginning of the third month of fcetal life meet beneath the nasal septum, uniting with each other and with the nasal septum, the union taking place from before backward. The incisive foramen indicates the place of meeting of the premaxillary and palate shelves, which closes the primitive communication between the oral and the nasal cavity. A want of union of the palate shelves presents an arrest of development known as cleft-palate. The uvula is similarly formed by the union of the posterior ends of the lateral palate anlages, and a failure to unite may produce a bifid uvula. The transverse palatine ridges are better developed in the infant than in the adult, and may assist in holding the nipple in sucking.
Variations. — Cleft-palate and bifid uvula were mentioned above. The transverse palatine ridges are quite variable in number and prominence. On each side of the incisive papilla there is often found a small pit or shallow tube, a vestige of the embryonal incisive canal (Merkel). Sometimes there is instead a single median pit, representing the lower end of the incisive (Stenson's) canal. These pits are remnants of the primitive embryonic communication between mouth and nasal cavities.
Comparative. — The palate is absent in fishes and amphibia, the ohoanse opening directly into the primitive mouth cavity. In some birds, the palate shelves fail to unite, leaving a normal cleft-palate. The incisive (Stenson's) canal remains open permanently in some mammals (e. g., ruminants), bifurcating above and thus placing the mouth cavity in communication with the nasal cavity on each side in the vicinity of Jacobson's organ. The transverse palatine ridges are much better developed among many mammals, especially the carnivora.
THE TONGUE
The tongue [lingua] is a muscular organ covered with mucous membrane and located in the floor of the mouth. It is an important organ of mastication, deglutition, taste and speech. Upon its upper surface (figs. 854, 864) is a V-shaped groove (sulcus terminalis) indicating the division of the tongue into two parts. The larger anterior part, or body [corpus linguae] belongs to the floor of the mouth, while the smaller posterior part, or root [radix linguae], forms the anterior wall of the oral pharynx. The inferior surface (facies inferior) of the tongue is chiefly attached to the muscles of the floor of the mouth, from the hyoid bone to the mandible (fig. 858). Anteriorly and laterally, however, the inferior surface of the body is free and covered with mucosa. The superior surface of the body is called the dorsum. It is separated from the inferior surface by the lateral margins, which meet anteriorly at the tip [apex linguae].
The dorsum of the tongue usually presents a slight median groove [sulcus medianus linguae]. Its posterior end corresponds to a small pit of variable depth, the foramen ccecum, which is placed at the apex of the V-shaped terminal sulcus, The dorsum of the body has a characteristic rough appearance due to numerous small projections, the lingual papillce.
Lingual papillae. — Five or six varieties of papilte are distinguished, between which intermediate forms occur. The conical [papillse conices] and thread-like [papillae filiformes] are most numerous, and are arranged more or less distinctly in rows parallel with the terminal sulcus (fig. 856). They are best developed toward the mid-line of the dorsum in its posterior part. As shown in vertical section (fig. 856), each papilla consists of an axial core of vascular fibrous tissue (from the lamina propria) often beset with smaller secondary papillse. The stratified squamous epithelial covering often presents numerous thread-like prolongations from the apex of the papilla. The papillse vary from 1 to 3 mm. in length.
The fungiform ("toad-stool shaped") papillae are somewhat similar to the conical in structure, but larger and more prominent, with an expanded free portion and a slightly constricted stalk of attachment. They are relatively few in number and are scattered irregularly over the dorsum, being most numerous near the margins (fig. 864). They are easily distinguished in hfe by their larger size and reddish colour. A smaller, flattened variety of the fungiform is sometimes called the lenticular ('lens-shaped') papillse. (This term, however, is apphed by Toldt to certain small rounded- elevations with underlying lymphatic nodules in the mucosa of the root of the tongue.)
The vallate (circumvallate) papillfe, usually seven to eleven in number, are conspicuous and arranged in a V-shaped line parallel with and slightly anterior to the sulcus terminalis, (figs. 854, 857). They are, as a rule, shaped hke short cyhnders, 1 to 2 mm. in width, and somewhat less in height. As is shown in section (fig. 857), each is surrounded by a trench or fossa, into the bottom of which open ducts of the serous glands of von Ebner. On the sides of the fossaj are the taste-buds, as described in the section on Sense Organs.
The foliate papillie are represented by a few (five to eight) parallel transverse or vertical folds of mucosa, along the margins of the tongue just anterior to the glosso-palatine arch on each side (fig. 864). They are variable in size and sometimes rudimentary. In structure they somewhat resemble the vallate papillse (though of different form), their walls being studded with taste-buds.
The free inferior surface of the tongue (fig. 858) is covered by a thin smooth mucosa. In the median line is a prominent fold, the frenulum, which connects the tongue with the mandible and the floor of the mouth. On each side of the inferior surface, an irregular, variable, fringed fold, the plica fimbriata, extends from near the apex backward approximately parallel with the lateral margin of the tongue (fig. 858). Between the frenulum and the plicae fimbriatse, the lingual (ranine) veins are visible on each side beneath the mucosa.
The root (or base) of the tongue [radix linguae] belongs to the pharynx, but is here included with the mouth for convenience of description. Its free surface is directed posteriorly, and represents the continuation of the dorsum linguae (fig. 854). Laterally it is continuous with the region of the palatine tonsils. Infe-
Fungiform papillee
riorly it extends to the epiglottis, with which it is connected by a median and two lateral folds, between which are the depressions known as the valleculce. The mucosa over the root of the tongue is irregular and warty in appearance due to the projections of the underlying nodular masses of lymphoid tissue, the lingual follicles. A crypt or tubular pocket of surface epithelium usually dips down into each of these follicles, as seen in surface view (fig. 854), and shown in section (fig. 859) . The follicles vary from 34 to 102 in number, the average being 66 (Ostman) j and are somewhat irregular in size and form. They are often arranged in more or less distinct longitudinal rows, with corresponding folds of the mucosa (Jurisch). The lingual follicles are collectively designated as the lingual tonsil [tonsilla linguae]. Between the lingual follicles and around the periphery of the lingual tonsil there are found smaller ordinary nodules (without crypts) and indefinite
to the foliate papiUse (i. e., in the regions of the taste-buds), the mucous glands are displaced by the serous glands (of von Ebner), which have a watery secretion (fig. 860). Finally, on the inferior surface of the tongue, on either side of the frenulum near the apex, are the anterior lingual glands (glands of Nuhn or Blandin). Each is about 15 mm. in length, and is composed of a group of racemose glands with three or four very small ducts opening on the surface of the tongue near the plica fimbriata. The anterior lingual glands are deeply placed and are covered not only by the mucosa, but also by some of the longitudinal muscle fibres (inferior longitudinal and styloglossus). This gland is of the mixed type, though chiefly mucous.
Fig. 859. — From a Section of the Lingual Tonsil op an Adult Man. X 20. 1. Pit containing leucocytes which have infiltrated its epithelium on the left side ; that on the right is almost intact. (Lewis and Stohr.)
Blood vessel
Muscles of the tongue. — A layer of fibrous connective tissue, the lingual septum, separates the halves of the tongue, extending in the median plane from the apex to the root, where it is attached below to the hyoid bone. The muscles of the tongue are classified as extrinsic and intrinsic. The extrinsic muscles (fig. 855) extend into the tongue from without. They are the hyoglossus, chondroglossus, genioglossus, styloglossus, and glossopalatinus (palatoglossus), all of which are described elsewhere (see Section IV.)
The intrinsic muscles. — The longitudinalis superior (fig. 861) is a superficial longitudinal stratum extending from the base to the apex of the tongue, immediately beneath the mucosa of the dorsum, to which many of its fibres are attached. The longitudinalis inferior (fig. 861) is composed of two muscle-bands extending from base to apex on the inferior surface of the tongue, and ia situated between the hyoglossus and the genioglossus, some of its fibres near the apex mixing with the styloglossus, while dorsaUy some are attached to the hyoid bone. The transversus linguae (fig. 861) consists of fibres which pass transversely, and is situated between
the superior and inferior longitudinal muscles. The fibres arise from, or pass through, the septum linguae, and are attached to the mucosa of the dorsum and lateral margins of the tongue. The verticalis linguae (fig. 861) is composed of fibres which pass from the mucosa of the dorsum to the mucosa of the inferior surface of the tongue, interlacing "with those of the other intrinsic and extrinsic muscles.
Verticalis linguae
Vessels and nerves. — The lingual arteries furnish the principal blood-supply. The lingual veins carry the blood from the tongue to the internal jugular. The lymphatics form a network in the lamina propria, connected with a deeper network in the submucosa. The latter forms plexuses around the lingual follicles. The efferent lymph-vessels from the tongue empty chiefly into the superior deep cervical lymph-nodes. (For details concerning the blood- and lymphvessels, see Sections V and VI.) The nerves are motor and sensory. The hypoglossal nerve
Fig. 862. — Schematic Representation of the Distribution op tee Sensory Nerves in'the Mucous Membrane op the Tongue. (Areas of distribution according to R. Zander. White dotted area indicates vagus; oblique lines, glosso-pharyngeal; horizontal lines lingual nerves.)
Left lingual nerve
supplies the intrinsic and all the extrinsic muscles of the tongue except the glossopalatinus (palato-glossus), which is supplied from the pliar}'ngeal plexus. The sensory nerves (fig. 862) are: — the lingual nerve, a branch of the mandibular division of the fifth, which, after joining with the'chorc'.a tympani from the seventh, is distril^uted to the anterior two-thirds of the tongue and represents the nerve of touch; the Ungual branches of the glossopharyngeal, which are distrib-
and the superior laryngeal branch of the vagus, which supplies a small area near the epiglottis.
Development. — The development of the tongue is quite complicated. In general, the body of the tongue is derived from the region corresponding to the ventral portion of the first arch, just behind the mandible. It does not develop from the tuberculum impar, however, which is a transitory structure (Hammar). The epithelium of the body of the tongue is probably of ectodermal origin. The root of the tongue develops from the corresponding lower portion of the second or hyoid arch, and its epithelium is endodermal in origin. The transverse groove between the two arches later becomes the sulcus tenninaUs. At the middle of this groove there is an ingrowth of the epithelium to form the anlage of the thyreoid gland. The foramen ccecum and the occasional ductus linguaHs represent persistent portions of the thyreoid duct. The third arch does not appear to enter into the formation of the tongue, but forms the epiglottis (Hammar).
The musculature of the tongue appears to develop from the mesenchyme in situ although its innervation from the hypoglossal would indicate a derivation from the occipital myotomes. A pair of premuscle masses appears in the 9 mm, embryo, the individual extrinsic muscles being distinguishable at 14 mm., and the intrinsic at 20 mm. (W. H. Lewis). The glands appear in the fourth fcetal month as solid epithelial downgrowths which later acquire a lumen. The mucous glands appear first, the serous slightly later. Longitudinal folds in the mucosa of the
Deep portion of submaxillary gland
radix appear in the third or fourth fcetal month (Jurisch). The lymphoid tissue appears somewhat later as aggregations in the lamina propria, chiefly around the gland-ducts. From the beginning, the lymphoid structures are subject to marked individual variations. Characteristic, well-developed lingual follicles do not appear until some time after birth, however (Jurisch). Of the lingual papilloe, the fungiform appear at the end of the third foetal month, followed shortly by the fihform and vallate. The formation of the papillae is not completed at birth, however, since they later undergo changes in number, form, size and arrangement. The foliate papillae appear about the fifth foetal month. They are best developed in infants, undergoing retrogressive changes in the adult (Stahr). The same is true of the plicae fimbriatae.
Variations. — Of the manifold variations in the structure of the tongue, some have already been mentioned. Additional mucous glands sometimes occur along the margin of the tongue (completing Oppel's "glandular ring"). In "tongue-tied" individuals, the frenulum is abnormally short. A forked tongue (normal in some animals) is a rare congenital anomaly. Another rare variation is the so-called "hairy" tongue, due to hypertrophy of the filiform papillae. While the V-shaped arrangement of the vallate papillae is typical, the Y-form (two to four papillae in the median line forming the stem of the Y) is nearly as frequent. Indeed, in some of the coloured races the latter type seems to predominate. The sulcus terminalis and foramen caecum are often indistinct and sometimes absent.
Comparative. — The tongue of fishes and lower amphibia contains neither glar.ds nor intrinsic musculature. Among higher vertebrates, the tongue varies exceedingly in form and structure, but always contains intrinsic musculature and mucous glands. The latter primitively form a ring around the margin and root of the tongue (Oppel). The serous glands occur only in mammals, and are associated closely with the papillae bearing taste-buds. '
The plica fimbriata in man is homologous with the 'sublingua' of lower mammals. According to Gegenbaur, the 'sublingua' represents the entire primitive vertebrate tongue, but this view is opposed by Oppel. Among various mammals, the number of vallate papilte varies from one to thirty, but the V- or Y-arrangement is typical. The region of the foliate papillae ('marginal organ') is typical for mammals, and is much better developed in some (e. g., rabbit) than in man. The mucosa of the root of the tongue is always different from that of the body. The lingual papillae are especially developed in the tongue of carnivora.
THE SALIVARY GLANDS
Numerous glands — labial, buccal, palatine and lingual — have already been mentioned, which pour their secretions into the mouth cavity. In addition to these, there are three larger pairs, the salivary glands proper. They include the parotid, the submaxillary, and the sublingual (the latter really a group of glands).
angle of the mandible below.
Form and relations. — The parotid is somewhat prismatic or wedge-shaped (figs. 863, 864), with three surfaces and three borders or angles. The lateral surface is covered by skin and superficial fascia, and in its lower part by the platysma. The anterior surface overlaps the masseter and extends medialward in contact
with the posterior border of the mandibular ramus and with the posterior aspect of the internal pterygoid muscle. An irregular "pterygoid lobe" may extend between the internal and the external pterygoid muscles. The posterior surface is in contact with the sternomastoid muscle laterally, and with the styloid process and associated muscles medially. Between the sternomastoid and styloid process it touches the posterior belly of the digastric, and is in relation with the internal carotid and jugular vessels. The various structures in contact with the parotid gland often make more or less distinct grooves upon its posterior and anterior surfaces.
Borders. — -The anterior border usually extends from below obliquely upward and forward so as to give the whole superficial surface a triangular appearance. Near the upper end of the anterior border, the parotid duct leaves the gland, and just above this there is usually a small separate accessory lobe [gl. parotis accessoria], of variable form and size. The branches of the facial nerve also emerge from the anterior border. The posterior border extends along the anterior aspect of the sterno-mastoid muscle up to the mastoid process. The medial border is deeply placed (at the junction of the anterior and posterior surfaces), and approaches the wall of the pharynx.
external auditory meatus. From the upper extremity emerge the superficial temporal vessels and the auriculo-temporal nerve. The lower extremity is separated by the stylo-mandibular ligament from the posterior end of the submaxillary gland.
Fascia. — As shown in fig. 865, the parotid gland is enclosed in a sheath (called the parotid fascia or aponeurosis) derived from the deep fascia of the neighbourhood. The superficial layer of the sheath covers the lateral surface of the gland, while the deep layers correspond to the anterior and posterior surfaces of the gland. The sheath is very feeble or deficient at the medial angle. The superficial and deep layers of the parotid sheath unite below to form a thick fascial band extending from the angle of the mandible to the sterno-mastoid muscle.
Contents. — Within the sheath, the parotid gland is in intimate relation with numerous important structures. Extending along the medial border, and partly embedded in the gland, is the external carotid artery, dividing above into the superficial temporal and internal maxillary (including the origins of the deep auricular and transverse facial); and the posterior facial (temporo-maxillary) vein and branches. The auriculo-temporal nerve passes through the upper part of the gland, while the facial nerve passes somewhat horizontally through it, dividing into its temporo-facial and oervico-facial divisions. Finally, there are embedded m the gland two or three deep lymphatic nodes, which receive lymphatic vessels from the external auditory meatus, the soft palate and the posterior part of the nasal fossa; and several superficial_ nodes, which receive lymphatic vessels from the temple, eyebrows and eyelids, cheek and auricle.
Duct, vessels and nerves. — The duct of the parotid (Stenson's) issues from tlie anterior border of the gland, crosses the masseter a finger's breadth below the zygoma, and turns abruptly medialward round its anterior border. It penetrates the fat of the cheek and the fibres of the buccinator muscle, between which and the mucous membrane it runs for a short distance before it terminates, sometimes on the summit of a little papilla, by a minute orifice. This opening is placed opposite the crown of the second upper molar tooth. The duct commences by numerous branches, which converge toward the anterior border of the gland, and receives in its passage across the masseter the duct of the accessory parotid gland. The canal is about the size of a crow-quill, length about 35 to 40 mm., diameter 3 mm. Its mucous membrane is covered for a short distance, beginning with its oral termination, by stratified pavement epitheUum, for the remainder of the distance by columnar epithelium. The coat of the duct is thick and tough, and consists of fibrous tissue intermixed with nonstriated muscle-fibres.
The nerves. — The parotid gland receives its secretory fibres from the otic ganglion, conveying impulses from the glosso-pharyngeal via the lesser petrosal and the auriculo-temporal; its sensory supply through branches of the fifth nerve; and its sympathetic supply from the carotid plexus. The lymphatics from the parotid gland terminate in the superficial and deep cervical glands, especially in the deeper group of parotid nodes embedded in the substance of the gland.
Variations. — The parotid is quite variable in size and in the form of its various processes, especially of the accessory lobe, as already mentioned. The lobulations are less distinct in infancy. Rarely the parotid is confined to the masseteric region, the retro-mandibular fossa being filled with a fatty tissue enclosing the vessels and nerves normally found with the gland.
The submaxillary gland [gl. submaxillaris] weighs 7 to 10 grams, and is of about the form and size of a flattened walnut. It consists of a chief or superficial part, and a smaller deep process. The chief portion is located in the digastric triangle, and presents three surfaces — superficial, deep and lateral (figs. 847, 866).
Surfaces. — The superficial or latero-inferior surface is covered by skin, superficial fascia, platysma and deep fascia (which forms an incomplete capsule around the gland). It is crossed by the facial vein and by cervical branches of the facial nerve. Several lymphatic glands, which receive vessels from the anterior facial region, lie upon or embedded in this surface.
The lateral surface is the smallest of the three. It is in contact with the submaxillary fossa of the medial surface of the mandible, and with the lower part of the internal pterygoid muscle. The posterior aspect of the gland is deeply grooved by the external maxillary (facial) artery and is separated from the parotid gland by the stylo-mandibular ligament. The deep or medio-superior surface is in contact with the lower surface of the mylohyoid, and behind this with thehyo-
glossus, stylohyoid and posterior belly of the digastric.
The deep portion is a tongue-like process which passes from the deep surface of the submaxillary gland around the posterior border of the mylohyoid muscle, and extends forward in company with the duct, under cover of (above) the mylohyoid, and in relation with the hyoglossus and genioglossus muscles. At its commencement, the deep process lies just below the submaxillary ganglion and ■ anteriorly it gives off the submaxillary duct as it approaches the sublingual gland.
The submaxillary (Wharton's) duct springs from the deep surface of the superficial part of the gland; it passes forward and inward, along the medial surface of the deep lobe, and opens by a small orifice on the summit of a papilla [caruncula sublinguahs] by the side of the frenulum of the tongue. It is crossed superficially by the lingual nerve. It hes at first between the mylo-
Secretory duct
hyoid and hyoglossus; next, between the mylohyoid and genioglossus; and lastly, under cover of the mucous membrane of the mouth, between the genioglossus and the sublingual gland. The duct is about 5 cm. in length, and has comparatively thin walls. It is lined by columnar epithelium.
The nerves. — The submaxillary gland receives its secretory fibres from numerous small sympathetic ganglia situated on the submaxillary duct and in the hilus of the gland, these conveying impulses from the chorda tympani; its sensory branches probably come from the geniculate ganglion, and its sympathetic branches from the cervical sympathetic.
The sublingual gland [gl. sublingualis] — the smallest of the salivary glands (2 to 3 gm.) is in reality a group of glands forming an elongated mass in the floor of the mouth under the tongue (fig. 847) . Above, it forms a distinct ridge, covered by a fold of mucosa (plica sublingualis) upon which its ducts open (fig. 866). It is flattened from side to side, its loioer border resting upon the upper surface of the mylohyoid, its lateral surface in contact with the sublingual fossa of the mandible, and its medial surface with the geniohyoid, geniohyoglossus, lingual nerve, deep lingual artery and submaxillary duct (fig. 863). Anteriorly it touches its fellow of the opposite side, while 'posteriorly it is often related with the deep process of the
inantly mucous.
Ducts. — The minor sublingual duels [ductus sublinguales minores], ducts of Rivinus, vary from five to fifteen or more in number, and open on minute papillae along the crest of the plica sublingualis (fig. 858). The anterior portion of the gland often forms a larger [Bartholin' s) duel [ductus sublingualis major] which opens alongside the submaxillary duct on the caruncula sublingualis (figs. 858, 866).
Nerves. — The sublingual glands receive their secretory fibres from the subma.xillary and associated sympathetic ganglia, conveying impulses from the chorda tympani; sympathetic, branches come from the cervical sympathetic and sensory fibres probably from the geniculate ganglion, although this question needs further investigation.
Development of the salivary glands. — The salivary glands appear early as buds from the ectodermal epithelium extending into the adjacent mesenchyme of the mouth cavity. The parotid appears first on the side of the mouth cavity in an embryo of 8 mm., as a groove which becomes tubular and pushes back over the masseter to the ear region, developing branches (at first solid). Around the gland and between the branches is mesenchyme which becomes condensed to form the peripheral capsule. The submaxillary gland appears in the 13 mm. embryo as a ridge in the epithelium of the alveolo-lingual groove. The solid cord (lumen appearing later) grows forward to the region of its adult orifice. Its posterior end extends backward and gives off solid branches which later form the acini and duct system of the mature gland. The sublingual glands appear somewhat later (24 mm. embryo) as a series of separate anlages of variable number, budding off in the positions where the adult ducts empty. The major sublingual gland, if present, appears fii'st. The histogenetic development of the salivary glands is not completed until some time after birth, probably about the time of weaning. However, mucin cells appear in the sublingual glands in the foetus of four months and serous cells in the parotid of five months.
Variations. — The duct of Bartholin is present in about half of the cases, and the corresponding anterior part of the gland may be more or less separate [gl. sublingualis major]. The number of ducts may reach thirty (TiUaux). Rarely processes from the gland may penetrate the mylohyoid, appearing on its lower surface in one or more places (Moustin). Most of the variations in this and the other salivary glands are due to developmental irregularities.
Comparative. — Oral glands are not found in the lower aquatic vertebrates. Mucous glands occur in all terrestrial vertebrates, but true sahvary (digestive) glands appear only in mammals. Although great variations occur in the different species of mammals, those in man (excepting the anterior lingual) are typical for the order. The sublingual gland, however, often occurs as two separate glands, corresponding to the sublinguaUs major and minor. The parotid gland apparently has no representative in forms below mammals. In some mammals (e. g., monkey) it has two main lobes — a larger superficial and a smaller deeper lobe between which lies the facial nerve (Gregoire). Other oral glands (e. g., orbital, zygomatic) appear in some mammals.
The teeth [dentes] are highly specialized structures developed in the oral mucosa as organs of mastication and also (in man) of speech. The adult individual with perfect dentition has thirty-two teeth, arranged arch-like in the sockets (alveoli) of the maxilla and the mandible. Sixteen belong to the upper or maxillary arch; and sixteen to the lower or mandibular. The four central teeth in each dental arch are the incisors; the tooth next to these on each side is the canine; behind these are the two premolars (bicuspids) ; and lastly the three molars. This relation of teeth is expressed by the following dental formula:
Form. — Each tooth [dens] has a crown [corona dentis], the portion exposed beyond the gum, and covered with enamel (figs. 871, 872). The root [radix dentis] is the portion covered with cementura and embedded in the bony socket. At the line of union of crown and root is the slightly constricted neck [coUum dentis]. The surface of the tooth directed toward the lip (or cheek) is termed the labial (or buccal) surface [facies labialis; f. buccalis]; while that toward the tongue is the lingual surface [f. lingualis]. The crowns of the opposite arches meet at the masticating surface [f. masticatoria]. The surfaces in contact with the adjacent teeth of the same arch [facies contactus] are, for the incisors and canines, termed medial and lateral, while those for the premolars and molars are termed anterior and posterior.
Structure. — As shown in longitudinal section (fig. 873), each tooth has a central cavity [cavum dentis] or pulp cavity, which is filled with pulp [pulpa dentis]. The pulp is a soft fibrous tissue richly supplied with vessels and sensory nerves which enter the root canal through the apical /orame?i [foramen apicis dentis]. The body of the tooth, both crown and root, is composed of a dense modified variety of bone called dentine [substantia eburnea]. It is yellowish in colour. The striated appearance of the dentine is due to numerous fine canals, the dentinal
Cingulum
tubules. These contain 'Tomes' fibrils,' which are long protoplasmic branches of the odontoblasts, a layer of cells on the surface of the pulp. At the outer surface of the dentine are numerous small, irregular interglobular spaces, corresponduig in the root to Tomes' 'granular sheath' (fig. 873). The dentine of the crown is covered with a layer of white enamel [substantia adamantina], which is the hardest substance in the body. It is composed of numerous mmute
hexagonal -prisms [prismata adamantina] which are arranged perpendicular to the surface and are of epithelial origin. In adult teeth, the enamel is often worn through in places, exposing the yellowish dentine. The dentine of the root is covered by a thin layer of cementum [substantia ossea], a layer of bone which is very thin at the neck, but becomes thicker toward the root apex (fig. 873). Surrounding the root is the aUeolar periosteum, a fibrous membrane connecting the cementum firmly with the bony lining of the socket. For further details of the minute structure of teeth, works on histology may be consulted.
Marrow spaces of mandible
nally and of the palate or floor of the mouth internally. Like the mucosa of the mouth elsewhere, they are covered with stratified squamous epithelium. The lamina propria is especially thick and strong, and is firmly attached to the subjacent bone. Around the neck of each tooth, the epithelium of the gum forms an overlapping collar and the lamina propria is continuous with the alveolar periosteum (fig. 873).
characteristic chisel shape. The masticating surface is narrow and chisel-edged. In recently erupted teeth, the cutting edge is elevated into three small cusps, which soon wear down, leaving a straight edge. These cusps correspond to three indistinct ridges on the labial surfaces. The lateral angle of the crown is usually more rounded than the medial. The labial surfaces are slightly convex, the lin-
Wall of dental alveolus
gual slightly concave. The contact surfaces are somewhat triangular. The roots of the incisors are single, though often longitudinally grooved, indicating traces of a division. They are somewhat conical, but flattened from side to side, expecially the lower set, and are slightly curved lateralward.
The upper or maxillary incisors are much larger than the lower. They are lodged in the premaxilla, and are inclined downward and forward. They overlap the lower incisors in mastication, hence the masticating surface is worn off and rounded at its posterior edge, while the anterior edge becomes sharp and chisel-hke. The lingual surfaces of the crowns terminate near the gum in a low, inverted V-shaped ridge, the basal ridge or cingulum. At the apex of
medial upper incisor is distinguished from the lateral by its much larger size.
The lower or mandibular incisors are smaller than the upper, the cutting edges being only about half as wide. The lower mcisors are vertically placed, and the crown becomes narrower toward the neck. A cingulum is rarely visible. The medial lower incisor, unlike the upper, is slightly smaller than the lateral.
The canines.— (Figs. 868, 869, 870, 871.) The canine teeth [dentes canini] so-called from their prominence in the dog-tribe, are the longest of all the teeth (fig. 868). The crown is thicker and more conical than in the mcisors. The masticating surface forms a median angular poi nt, on either side of which the cutting
edge slopes to the lateral angle. The medial limb of the cutting edge is usually somewhat shorter than the lateral, rendering the crown asymmetrical. The labial surface is convex, the lingual somewhat concave. The root is single, long, flattened from side to side and grooved on the sides as in the incisors. The canine root is usually slightly curved lateralward. The bony alveolar protuberances [juga alveolaria] are more prominent than those of any other teeth.
The upper canine slants forward and overlaps the lower, as in the incisors. The upper canine also presents a well-marked cingulum, and usually a distinct lingual cusp (fig. 871) below which a slight median ridge extends along the lingual surface. On the lower canine, these structures are poorly marked or absent. The lower canine is somewhat smaller than the upper, and its root is occasionally bifid.
Mental foramen
crown presents on the masticating surface two prominent cusps, on account of which the premolars are often called 'bicuspids.' The buccal and lingual surfaces are convex especially from side to side, so that the crown is somewhat cylindrical in form, with flattened, quadrilateral anterior and posterior contact surfaces. The root is (usually) single and more or less flattened antero-posteriorly, and usually somewhat curved backward.
The upper premolars are distinguished from the lower by a greater antero-posterior flattening of the crown and by a deep groove separating the cusps (excepting at their anterior and posterior margins) on the masticating surface. In the first upper premolar the lingual cusp and surface are decidedly smaller than the buccal; and the root is frequently bifid or double (occasionally even triple). In the second upper premolar the lingual cusp and surface are as large as the buccal; and the root, though deeply grooved, is rarely bifid.
In the lower premolars, the crowns are more cylindrical in form, and the cusps are united by a median ridge so that the masticating surface presents two small pits. The roots are more rounded and tapering, and rarely grooved. In the first lower premolar (like the corresponding upper) the lingual cusp and surface are much smaller than the buccal, the lingual cusp sometimes being rudimentary; while in the second they are more nearly equal. The second lower premolar is often slightly larger than the first, while in the upper premolars the converse is true. It should be noted, however, that the premolars are quite variable in all respects, and it is therefore often difficult to identify the individual isolated teeth.
three to five masticating cusps (hence sometimes called 'multicuspids')- The crowns are massive, somewhat resembling rounded cubes, and the lingual and buccal surfaces present vertical grooves continuous with the fissures separating the cusps. The pulp cavity (fig. 872) has slight extensions corresponding to the cusps, and also communicates with the canals of the roots, which are usually two or three in number, and more or less curved.
The upper molars are most easily distinguished from the lower by the presence of a triple root. The masticating surface is nearly square with rounded angles. They each have typically four cusps, separated by grooves resembling a diagonally placed H (fig. 852). The crowns of the upper molars are obliquely placed so as to slant downward and slightly lateralward.
Each upper molar has three roots, two buccal and one Ungual or palatal. They are aU (especially the buccal) in more or less close relation with the floor of the maxillary antrum (of Highmore) (fig. 876). The buccal roots are flattened antero-posteriorly, and longitudinally grooved, and bent backward. The palatal root is more rounded, with a groove on the hngual surface, and usually bent medialward. Either of the buccal roots may fuse with the palatal, or there may be an extra fourth root.
As to the individual upper molars, the first has almost invariably four typical cusps (rarely only three, or with an additional fifth rudimentary). The second upper molar has only three cusps in about half of the cases (in Europeans), and four in the remainder. The third, or wisdom tooth [dens serotinus] is exceedingly variable in size and form (fig. 875). It has three cusps much more frequently than four, and its three roots are often more or less fused into a conical mass. It is usually much smaller than the other molars, and is absent in nearly one-fifth of all cases.
The lower molars have usually four or five cusps (two lingual, and two or three buccal) the fissures separating them being cross-shaped or stellate (fig. 864). The crowns incUne upward and slightly medialward. They have each two roots, anterior and posterior, flattened antero-posteriorly, and usually somewhat curved backward. The roots, especially the anterior, may be longitudinally grooved. The anterior has two root-canals, the posterior usually only one. The apices of the roots of the lower molars, especially of the third, approach the mandibular (inferior dental) canal (fig. 876).
Of the individual lower molars, the first is usually slightly the largest, and has five cusps in the great majority of cases (variously estimated at from 60 to 95 per cent.), otherwise four. The four main cusps (two buccal and two lingual) are separated by a cruciform fissure, which bifurcates posteriorly to embrace the small fifth cusp (which is placed shghtly to the buccal
side) when present. The second lower molar has usually four cusps (75 to 85 per cent, of cases) , otherwise five, the fifth usually small or rudimentary. The roots are sometimes confluent. The lower third or wisdom tooth, like the upper, is usually small and exceedingly variable (fig. 875). It has usually four or five cusps; but the number may be increased to six or seven,
l3s of lower jaw
The upper arch is slightly larger (due chiefly to the slant of the teeth, as previously explained) so that it shghtly overlaps the lower when the teeth are in occlusion. Thus, as showli in fig. 876, the upper incisors (and canines) overlap the lower. The buccal cusps of the lower premolars and molars fit into the groove between the upper buccal and lingual cusps; while the upper lingual cusps correspond to the groove between lower buccal and lingual cusps. This arrangement favors a more perfect mastication (see fig. 877).
due chiefly to the great width of the upper central incisor. The lower molars, however, especially the third, are wider (antero-posteriorly) than the upper, so that the two arches are nearly equal in length. The interdental line between the two arches is not straight, but shghtly convex downward (fig. 876). In both arches, the crowns of the incisors and canines are taller than those of the premolars and molars.
Vessels and nerves. — The vessels and nerves of the teeth are distributed partly to the pulp and partly to the surrounding alveolar periosteum. The arteries are all derived from the internal maxillary. Those for the upper teeth are the posterior superior alveolar and the anterior superior alveolar (from the infraorbital). Similar branches to the lower jaw are given off by the inferior alveolar. They give off twigs to the gums (rami gingivales), the alveolar
palatine foramea
periosteum (rr. alveolares), and the pulp cavities (rr. dentales). A dental branch enters each root canal through the apical foramen, and breaks up into a rich peripheral capillary plexus under the odontoblast layer. From this plex-us, the corresponding veins arise. There is a plex-us of peridental lymphatics, which anastomose with those of the surrounding gums, and drain chiefly into the submaxillary nodes. Lymphatics have also recently been demonstrated in the pulp of the tooth (Schweitzer).
The nerves are sensory branches derived from the trigeminus. Those for the upper teeth are from the anterior, middle, and posterior superior alveolar (fig. 735); while those for the lower teeth are from the inferior alveolar (fig. 736). These nerves give numerous branches to
Mandibular or lower set
the gums, alveolar periosteum, and pulp cavities. The latter enter with the corresponding vessels, and their distribution within the tooth is a subject of controversy. They may be followed easily to a plexus under the odontoblasts; but whether they end freely, or in connection with the odontoblasts (which by some are considered as peripheral sensory cells), or send fine terminal branches out into the dentinal canals is still uncertain.
Development of the teeth. — The teeth represent calcified papillae of the oral mucosa, the enamel being a derivative of the ectodermal epithehum, and the remainder of the tooth coming from the underlying mesenchyme. The first trace of the teeth appears in the human embryo of about 11 mm., in the form of an epithelial shelf, the dental ridge, extending into the mesenchyme corresponding to the future alveolar portions of the jaws (figs. 878, 879). From the dental ridge there is later produced a series of cup-shaped enlargements, the enamel organs, which become constricted off except for a slender neck attaching each to the common ridge. By the end of the third foetal month, the twenty enamel organs of the temporary or deciduous teeth are formed. The concavity of each enamel organ is filled by the dental papilla of mesenchyme.
A somewhat later stage in the organogenesis of a tooth is shown in fig. 880. The mesenchymal cells on the surface of the dental papilla, next to the enamel organ, form a single layer of columnar cells, the odontoblasts. These cells form the dentine upon their outer surfaces, gradually retreating toward the center of the tooth as the dentine increases in thickness. The first dentine formed is irregular, enclosing the spatia interglobularia. The odontoblasts remain through life just beneath the dentine on the surface of the pulp, sending slender processes, up into the dentinal tubules as previously noted in the structure of the adult tooth. The remainder of the dental papilla becomes the pulp, receiving its vascular and nerve supply at the point opposite the enamel organ, corresponding to the future root.
The enamel organ (fig. 880) is differentiated into three layers: a thin outer layer attached by the neck to the dental ridge; a thick middle layer (forming the spongy "enamel pulp"); and a single inner layer of cylindrical enamel cells, the adamantoblasts. The latter form the prisms, which are deposited gradually upon the outer surface of the dentine.
Surrounding the entire developing tooth there is formed a strong, fibrous connectivetissue membrane, the tooth-sac. The deeper part of this sac later becomes the alveolar periosteum around which the bony alveoli are formed. This bone may entirely surround the tooth-sac, excepting at the summit, where a foramen persists through which a process of connective tissue {gubernanilnm dentis) connects the tooth-sac with the overlying gum (see figs. 114, 881). Upon the inner surface of the tooth-sac, next to the root, the bony cemenlum is deposited upon the dentine. The root gradually elongates, and is usually not completed until long after the eruption. The remaining superficial portion of the tooth-sac undergoes pressure atrophy and absorption. The remnants of the enamel organ, however, persist and form a thin tough cuticle [cuticula dentis], Nasmyth's membrane, which is soon worn off when the crown is exposed at the surface.
From the remainder of the dental ridge, which lies on the lingual side of the deciduous teeth (fig. 878), the permanent teeth are later derived in a very similar manner. (Rudimentary indications of a prelacteal dental ridge have also been described.) The anlages of the permanent teeth therefore lie to the lingual side of the deciduous (fig. 883). From the posterior end of the dental ridge a process extends into the jaw behind the deciduous teeth, and from this process the permanent molars (which have no deciduous predecessors) are formed. At birth, although no teeth have yet been cut, there are present in the gums the anlages of not only all of the deciduous teeth, but also all of the permanent teeth, with two exceptions. Those of the second molars do not appear until six weeks after birth, and of the third molars not until the fifth year. The remnants of the dental ridges become broken up into small masses of epithehal cells, which persist for a variable time.
The deciduous teeth (figs. 882, 883) are much smaller in size than the permanent teeth, and their necks are more constricted. The enamel of the crown cap is thicker. In general, their form and structure otherwise is very similar to that
already described in the case of the permanent incisors and canines. The molars, however, are different. Their cusps on the masticating surface are very sharp and irregular. There are usually three 'cusps on the first upper molar and four on the second; four cusps on the first lower molar and five on the second. The roots
correspond to those of the permanent molars (three above and two below), but they are much more divergent, to allow room for the development of the corresponding subjacent permanent premolar teeth. The first molar is always considerably smaller than the second.
Calcification in the dentine and enamel of the teeth does not begin until the anlages of the crowns are well formed. The process of calcification follows that of the development of the tooth in general, beginning in the superficial portion of the crown and gradually spreading toward the root. Calcification in the deciduous teeth begins during the fifth foetal month, and at birth the crowns are nearly completed (fig. 885). Of the permanent set of teeth, only the first molar has begun to calcify at birth (fig. 886). Calcification of the other permanent teeth begins during the second year; excepting the second molar, which begins during the fifth, and the third molar, which begins about the eighth year. There are, however, great variations
Eruption of the teeth. — -Oa account of pressure due to growth and expansion at the root of the tooth (and probably other obscure factors), the crowns are pushed toward the surface. The overlying portion of the tooth-sac, together with corresponding portions of the temporary alveolar bone, are absorbed, and the crown is "cut," i. e., breaks through the surface of the gum in eruption. In the case of the permanent teeth, this is normally preceded by a shedding of the deciduous teeth. The latter have been loosened by the absorption of their roots, which is perhaps due largely to the activity of certain odontoclasts (like the osteoclasts of bone) which are found in the region of absorption.
Time and order of eruption. — The time of the eruption of the various teeth is subject to great variation, so that no two investigators agree upon it. Aside from the wisdom teeth, the time of eruption is most variable in the canines and premolars, and least variable in the first permanent molars (Rose). The eruption averages four and one-half months earliei in the male, and is also earlier in well-to-do and city children (Rose). The order in which the teeth appear is less variable. The average time at which the various deciduous and permanent teeth appear is indicated approximately in the following table.
Variations. — The great variabihty of the teeth has already been emphasized, and numerous variations described in connection with the various individual teeth and their development. In number, the teeth may be reduced, due to absence (oftenest of the third molar) or incomplete development with failure of eruption. An increase in the normal number is less common' It may be only apparent, due to the retention of a deciduous tooth. There may rarely, however, be a true extra third incisor or premolar, or a fourth molar. Aberrant teeth may occur either on the labial or palatal side of the dental arch. A third dentition appears rarely in old age. In form, there is much greater variation as before mentioned. All intermediate forms between rudimentary and fully developed teeth may occur. Fusion between neighbouring teeth is sometimes found, and deformities in the dental arches necessarily accompany palatal defects involving the alveolar arches.
Comparative. — As the oral mucosa represents an invagination of the integument, so the teeth are morphologically equivalent to dermal papilliE. The close relationship between the teeth and the dermal appendages is clearly shown among many of the lower vertebrates, but most clearly in the Selachians (which include sharks and allied forms). In fig. 887, which illustrates a sagittal section through the lower jaw of a young dogfish, it is clearly evident that the external placoid scales or 'dermal teeth' are continuous with the equivalent oral teeth at the oral margin of the jaw. Both the dermal teeth and the oral teeth are composed of dentine which presents an enlarged base and a somewhat conical apex. The base is embedded in the fibrous lamina propria (often in bony plates) while the apex projects through the epithehum and is covered with a thin cuticular layer the "enamel membrane." True enamel is usually rudimentary or absent in the primitive teeth of lower vertebrates, and represents a secondary acquisition. The dentine is in aU cases derived from the connective tissue, and the enamel from the epithelium .
The process of development of the primitive oral teeth is also iDustrated in fig. 887. Just within the oral margin there is a shelf-like downgrowth of the ectodermal epithelium, forming a primitive germinal ridge. Along this ridge may be seen the anlages of several rows of teeth in various stages of development. As fast as the mature teeth at the oral margin are worn off, new teeth pass up from below to replace them. Thus the primitive form of dentition is polij■phyodont, with many sets of teeth developed successively thi'oughout hfe. As we pass up the vertebrate scale there is a tendency to a reduction in the number of sets, although there is a
wide variation among the various forms. In most mammals, as in man, the number of sets of teeth has been reduced to two, or diphyodojit dentition, with only traces of an earher (prelacteal) and also a later (post-permanent) set. In some mammals (monotremes, oetacea) the dentition has been reduced to a single set, jnonophyodont, while in birds all except rudimentary traces of dentition have been lost.
pAs may be further observed in fig. 887, the primitive teeth are of a recurved conical form, and serve primarily for grasping and holding the food. The speciahzation of the teeth for purposes of mastication is in general a secondary acquisition amongst higher vertebrates.
It is also noteworthy that the primitive teeth, as found among nearly all forms below the mammals, are practicaOy alike in form, i. e., homodont. Among mammals, however, there is a marked speciahzation of the teeth, or helerodont dentition. The mammalian teeth are usually differentiated into four distinct classes, incisors, canines, premolars and molars, similar to those found in man.
primitive series have been lost. This reduction in the number of teeth is probably correlated with the general reduction in the jaws, which are relatively much larger and stronger in the savage races and lower animals. The third molar, or wisdom tooth, is probably now on the road to extinction, due to a continuation of the same evolutionary process.
Another interesting problem, concerning which there has been much speculation, is the origin of the multicuspidate mammalian molar. It has clearly been derived from the primitive conical type of the homodont dentition, but as to the method of evolution there is a difference of opinion. According to one view (the 'concrescence' theory), the molar has been derived by a process of fusion, each cusp representing a primitive conical tooth. Another view (the 'differentiation' theory) is that the molar represents a single primitive tooth, upon the crown of which the various cusps have been differentiated. According to a third view, which is a compromise, the tritubercular (tricuspid) form of tooth, which is that found in the earliest fossil mammals, was derived by a process of concrescence of three primitive teeth, while from this tricuspid form the multicuspidate molar has been derived by a process of differentiation.
THE PHARYNX
The pharynx is a vertical, tubular passage, flattened antero-posteriorly, and extending from the base of the cranium above to the beginning of the oesophagus below. Posteriorly, it is in contact with the bodies of the upper six cervical vertebrae. Laterally, it is in relation with the internal and common carotid arteries,
the internal jugular vein, the sympathetic and the last four cranial nerves. Anteriorly, it communicates above with the nasal cavity, beneath this with the oral cavity, and below with the laryngeal cavity. The pharynx is correspondingly divided into three parts: the nasal -pharynx [pars nasalis], which is exclusively respiratory in function; the oral pharynx [pars oralis], which is both respiratory and alimentary; and the laryngeal pharynx [pars laryngea], which is almost entirely alimentary.
ing it with the widened oral pharynx, and is again somewhat narrowed at the junction of oral and laryngeal pharynx (fig. 888) . It is narrowest at the point where it joins the oesophagus below. In sagittal section (fig.' 848), it is evident that the anterior and posterior walls are closely approximated in the laryngeal pharynx, and have only a small space between them in the oral pharynx. The nasal pharynx, however, has a considerable antero-posterior depth, and by its bony walls is always kept open for respiratory purposes.
Structure. — The pharynx approaches the typical structure of the alimentary canal, yet differs from it in several important respects. The lining mucosa is continuous with that of the various cavities which open into the pharynx. Above, it is closely adherent to the base of the cranium, where it is thick and dark in colour. It becomes thinner where it approaches the openings of the auditory tubes and choana;; and below it is paler and thrown into longitudinal folds. The epithehum of the greater part of the nasal pharynx (from the orifice of the auditory tube upward) is stratified cihated columnar, while that of the remainder of the pharynx is stratified squamous.
External to the mucosa, there is a characteristic fibrous membrane, the pharyngeal aponeurosis [fascia pharyngobasilaris], which is well marked above, but below it loses its density and gradually disappears as a definite structure. Above, it is attached to the basilar portion of the occipital bone in front of the pharyngeal tubercle. Its attachment may be traced to the apex of the petrous portion of the temporal bone, and thence to the auditory (Eustachian) tube and medial lamina of the pterygoid process. It descends along the pterygo-mandibular ligament to the posterior end of the mylohyoid ridge of the lower jaw, and passes thence along the side of the tongue to the stylohyoid ligament, the hyoid bone, and thyreoid cartilage.
External to the pharyngeal aponeurosis is a thick muscular layer, made up of various crossstriated muscles, as will be described later. Outside of the muscular layer is a thin fibrous tunica adventitia, connected with the adjacent prevertebral fascia by a loose, areolar tissue. This loose tissue allows movement of the pharynx, and also favours the spreading of postpharyngeal abscesses.
The nasal pharynx (figs. 848, 888) belongs, strictly speaking, with the nasal fossa as a part of the respiratory rather than the digestive system. Its anterior wall is occupied by the two choance (posterior nares), with the nasal septum between them. The floor is formed by the upper surface of the soft palate and in a direct posterior continuation of the floor of the nasal fossae. Posteriorly, however, the floor presents a more or less narrowed opening, the pharyngeal isthmus, which communicates with the oral pharynx below. The isthmus is formed anteriorly by the uvula, laterally by the posterior (pharyngo-palatine) arches. These slope backward and downward to the posterior wall of the pharynx, which forms the posterior boundary of the isthmus. The floor and isthmus change their form and position greatly during the action of the palatal muscles, as will be mentioned later.
The lateral wall of the nasal pharynx presents above and behind, corresponding to its widest point, a wide, slit-like lateral extension, the pharyngeal recess [recessus pharyngeus] or fossa of Rosenmueller (fig. 888). Below and in front of this recess, the greater part of the lateral wall is occupied by the aperture of the auditory (Eustachian) tube [ostium pharyngeum tubse]. This is a somewhat triangular, funnel-shaped opening, with an inconspicuous anterior lip [labium anterius], a more distinct posterior lip [labium posterius], which presents posteriorly a rounded prominence (due to the projecting cartilage of the auditory tube), called the torus tubarius. The prominence of the posterior lip facilitates the introduction of the Eustachian catheter, in connection with which the location of the aperture in the mid-lateral wall just above the level of the floor of the nasal fossa should be carefully noted. On the lower aspect of the triangular apertm-e is a slightly rounded fold, the levator cushion, which is a prominence caused by the levator palati muscle. A fold of mucosa descending from the posterior lip of the aperture to the lateral pharyngeal wall is the plica salpingo-pharyngea (due to the m. salpingo-pharyngeus). An inconspicuous plica salpingo-palatina descends from the anterior lip to the soft palate.
The posterior wall (fig. 848) of the nasal pharynx slopes from below upward and forward, passing (at the level of the anterior arch of the atlas) into the roof [fornix pharyngis]. The roof is attached chiefly to the basi-occipital and basisphenoid bones, extending laterally to the carotid canal of the pyramid, and anteriorly to the base of the nasal septum. In the posterior wall of the nasal pharynx there is found in the mucosa a variable and inconstant blind sac, the pharyngeal bursa.
The mucosa of the roof, and to a certain extent also of the posterior wall, especially in children, is thrown into numerous folds, which may be irregular or radiate from the neighbourhood of the bursa. There is often a median longitudinal groove (or sometimes ridge) at the posterior (inferior) end of which is the bursa. These folds of the mucosa contain much lymphoid tissue, both diffuse and in the form of numerous characteristic lymphoid nodules, with crypt-like invaginations of the surface epithelium. This area constitutes the pharyngeal tonsil [tonsilla pharyngea] (fig. 890), which is well-developed in children (often abnormally enlarged, producing 'adenoids'), but usually, though not always, atrophied in the adult. According to Symington, the involution of the pharyngeal tonsils begins at 6 or 7 years, and is usually completed at 10 years. In the region of the pharyngeal tonsil and elsewhere, the mucosa presents numerous small racemose mucous glands, especially thick in the palatal floor of the nasal pharynx and similar to those of the oral cavity.
geal isthmus with the nasal pharynx and below with the laryngeal pharynx. Its posterior wall presents no special features. The anterior wall is deficient above, where there is a communication with the mouth cavity through the isthmus
Fig. 889. — Vertical Section op a Human Palatine Tonsil, a, Stratified epithelium; b, basement membrane; c, tunica propria; d, trabeculse; e, diffuse lymphoid tissue; /, nodules; h, capsule; i, mucous glands; k, striated muscle; I, blood vessel; q, pits. (From Radasch.)
faucium. The faucial isthmus is bounded above by the uvula, laterally by the anterior (glosso-palatine) arches, and below by the dorsum of the tongue in the region of the sulcus terminalis. Below the faucial isthmus, the anterior wall of
the oral pharynx is formed by the root of the tongue, which has been described previously. The lateral wall of the oral pharynx on each side presents the palatine tonsil, enclosed in a somewhat triangular tonsillar fossa [sinus tonsillaris]
and below by the root of the tongue.
The palatine arches are folds of the mucosa formed at the sides of the free posterior border of the soft palate, as already mentioned in connection with that organ. The anterior arch (or pillar) [arcus glossopalatinus] extends from the soft palate downward and forward to the lateral margin of the tongue, just behind the papillfe foliatse. It is a fold of mucosa due to the underlying glosso-palatine muscle, and inconspicuous except when this muscle is in action, or when the tongue is depressed. It forms the lateral boundary of the faucial isthmus. The posterior arch [arcus pharyngopalatinus] is a more prominent fold which extends from the soft palate in the region of the uvula downward and backward to join the postero-lateral aspect of the pharyngeal wall. It forms the lateral boundary of the pharyngeal isthmus, and encloses the pharyngo-palatine muscle, whose actior will be explained later.
The palatine tonsil [tonsilla palatina] (figs. 864, 889, 890, 891) is a flattened ovoidal body, usually visible through the mouth cavity and faucial isthmus, and located on each side of the oral pharynx. The tonsil is extremely variable in size, but in the young adult averages about 20 mm. in height, 15 mm. in width (antero-posteriorly) and 12 mm. in thickness.
The lateral or attached surface of the tonsil is covered by a thin but firm fibrous capsule, which is continuous with the pharyngeal aponeurosis, and in contact with the middle constrictor muscle of the pharynx (fig. 864). Just outside the constrictor, the tonsil is in relation with the ascending pharyngeal and ascending palatine arteries, but is separated by a considerable space from the external and internal carotids. Rarely, however, the lingual or external maxillary may extend up higher than usual, so as to be in close relation with the lower aspect of the tonsil. Further lateralward, the palatine tonsil is in relation with the internal pterygoid muscle, and on the surface corresponds to a point somewhat above and in front of the angle of the mandible. The posterior border of the tonsil is thicker than the anterior, and forms a somewhat flattened surface in contact with the pharyngo-palatine muscle (fig. 891).
The medial or free surface of the tonsil is covered with mucosa and presents a variable number (12 to 30) small pits which are the openings into the tubular or slit-like crypts [fossulse tonsillares]. These crypts are somewhat more numerous in the upper part of the tonsil, and are sometimes branched or irregular in form. Usually they end blindly in the substance of the tonsil, surrounded by lymphoid tissue in characteristic nodular masses (fig. 889). The lymphocytes normally migrate through the stratified squamous epithelium lining the crypts (occasionally eroding passages of considerable size), and escape into the pharyngeal and mouth cavities, where they form the so-called salivary corpuscles. Around the periphery of the palatine tonsil, within the capsule, are many mucous glands (fig. 889), similar to those described in connection with the lingual and pharyngeal tonsils. The ducts of the mucous glands sometimes enter the crypts, but usually pass to the surface chiefly around the margins of the palatine tonsil.
Tonsillar plicae and fossae. — Connected with the tonsil are certain important folds and fossse. The plica triangularis (fig. 891) is a fold of variable extent and appearance, placed just behind the anterior arch, wider below and narrower above. According to Fetterolf, it is a prolongation of the tonsillar capsule, covered with mucosa. It may be adherent to the anterior part of the medial surface of the tonsil, or it may be free, in which case it covers a recess called the anterior tonsillar fossa. Occasionally there is a similar plica and fossa at the posterior border of the tonsil. Above the tonsil there is similarly a supratonsillar fossa [fossa supratonsillaris], which is also inconstant and exceedingly variable in size and shape. Killian found a supratonsillar fossa or canal in 41 of 105 cadavers.
Tonsillar vessels. — The arteries to the tonsil include the anterior tonsillar (from the dorsalis linguEe); the inferior tonsillar (from the external maxillary); the -posterior tonsillar (from the ascending pharyngeal) and the superior tonsillar (from the descending palatine). These pierce the capsule and supply the gland. The veins form a plexus around the capsule and empty into the lingual vein and the pharyngeal plexus. The lymphatic relations of the palatine tonsil are important. Afferent vessels are received from adjacent areas of the mucosa in the pharynx, mouth and lower part of the nasal cavity (v. Lenart). These are connected with an extensive lymphatic plexus around the lymph follicles within the tonsil. Efferent lymphatic vessels pass chiefly to the upper deep cervical lymphatic nodes. One of these, located just behind the angle of the mandible, is so closely connected with the tonsil, and so constantly
enlarged following tonsillar infection, that it has been called the tonsillar lymph gland (Wood). There are also communications with the submaxillary and superficial cervical lymphatic nodes. The tonsillar lymphatic vessels connect also with those of the lingual tonsil in the root of the tongue.
The tonsillar ring. — The two palatine tonsils, together with the lingual tonsil below and the pharyngeal tonsil above, form an almost complete ring of characteristic tonsillar tissue surrounding the pharynx and known as Waldeyer's 'tonsillar ring' (fig. 890). It is a highly specialized development of the diffuse lymphoid tissue which is found everywhere in the mucosa of the alimentary and respiratory tracts. It may be noted that the 'tonsillar ring' corresponds to the anterior limit of the embryonic foregut, hence the epithehum is of endodermic origin. The arrangement of the tonsils, together with their lymphatic connections, has suggested the widely accepted view that they are to be considered as protective mechanisms whose function is to intercept infectious material which has entered the mouth or nasal cavities. This theory is supported by the experiments of v. Lenart, who found that substances injected into the nasal mucosa are intercepted partly in the tonsils, and partly in the cervical lymph
Fig. 891. — The Left Palatine Tonsil, Showing the Arterial Supply. 1, Mesial aspect. 2, Postero-lateral aspect. E, lateral surface. B, posterior surface. T, medial surface. G, groove for pharyngo-palatine muscle. C, capsule. PT, plica triangularis. Arteries: AA, anterior tonsillar (from dorsal lingual); PA, posterior tonsillar (from ascending pharyngeal) ; SA, superior tonsillar (from descending palatine) ; lA, inferior tonsillar (anterior from dorsal lingual; posterior from tonsillar branch of internal maxillary). (Fetterolf : Amer. J. Med. Sc, 1912.)
phoid tissue elsewhere, is merely the production of lymphocytes.
Development of the tonsil. — According to Hammar, the palatine fossa (sinus tonsillaris) is a derivative of the second inner branchial groove and is visible in the human embryo of 17 mm. There appears in the floor of the fossa a tubercle (tuberculum tonsillare) which later becomes atrophied, excepting a portion which is converted into the plica triangularis. The primitive tonsil becomes divided into two lobes, upper and lower, by a fold (plica intratonsillaris) which later usually disappears. In the fojtus of about 100 mm. (crown-rump length) the epithelium of the floor grows into the subjacent mesenchyme in the form of somewhat irregular solid sprouts of epithelium. These later become hollow and form the crypts. Ai'ound them, in about the sixth fa-tal month, the lymphoid tissue begins to accumulate, at first diffusely, later forming characteristic follicles. The lymphocytes arise in situ from the connectivetissue cells (Hammar) or by immigration from the blood-vessels (Stohr). Retterer's claim that the tonsillar lymphoid cells are derived from the epithelial cells has not been confirmed.
The later fcetal development of the tonsil is subject to considerable individual variation. The supratonsillar fossa is a remnant of the upper part of the primitive sinus tonsillaris, which may be transformed into a canal by growth of adenoid tissue around it. It is inconstant and quite variable in size and extent. A portion of the sinus may likewise persist anteriorly (anterior tonsillar fossa) between the tonsil and the plica triangularis, but this portion is usually obliterated by fusion of the plica with the tonsil. The occasional retro-tonsillar fold and fossa are said to arise secondarily (Hammar).
Variations in the tonsil. — The palatine tonsil, like the lingual and pharyngeal tonsils, is an exceedingly variable organ. Many of the variations are developmental in origin, as above indicated, and ai-e therefore congenital. Furthermore, the tonsils, hke all lymphoid structures, are subject to marked age variations. Though fairly well formed at birth, they are yet somewhat undeveloped. They rapidly increase in relative size and complexity, however, being
best developed in childhood. After the age of puberty, they usually undergo certain retrogressive changes, become smaller in size, and in old age become almost entirely atrophied and lost. They are also markedly subject to inflammatory hypertrophy, especially in children. Variations in the relations of the blood-vessels were mentioned above.
The laryngeal pharynx (fig. 848) is the lower portion leading from the oral pharynx above into the oesophagus below (at the level of the lower border of the cricoid cartilage, usually opposite the sixth cervical centrum). It is wide above
Dorsum of tongue
and narrow below (fig. 888) . Its posterior walls are continuous with those of the oral pharynx and in relation with the vertebral centra. Its lateral walls are attached to the hyoid bone and the posterior part of the medial surface of the thyreoid cartilage. Anteriorly it is in relation with the larynx. In the median line above is the epiglottis, below which is the superior aperture of the larynx. Still lower is the posterior wall of the larynx, containing the arytenoid and lamina of the cricoid cartilage. Laterally, are the pharyngo-epiglottic folds, and below these on each side a deep, elongated fossa, the recessus piriformis, bounded laterally by the medial surface of the thyreoid cartilage. The mucosa of the laryngeal pharynx is similar to that of the oral pharynx, and contains racemose mucous glands, which are especially numerous in its anterior wall.
Muscles of the pharynx and soft palate. — These muscles (figs. 892, 893, 894), which are here grouped together for convenience of description, are chiefly sphincter-hke constrictors in function. They include the constrictors of the faucial isthmus (mm. glossopalatini), the constrictors of the pharyngeal isthmus
MUSCLES OF PHARYNX AND PALATE
(mm. pharyngopalatini) , the three pharyngeal constrictors, and also the levator and the tensor veil palatini, the m. uvulae and the stylo-pharyngeus. The stylopharyngeus and pharyngo-palatine muscles form an incomplete longitudinal layer within the more circularly arranged constrictors of the pharynx.
The muscles are arranged in layers either behind or in front of the aponeurosis, and in a horizontal section of the soft palate the following layers are met with from behind forward: (1) The mucous membrane on the pharyngeal surface; (2) the posterior layer of the pharyngo-palatinus (palato-pharyngeus) ; (3) the m. uvulae; (4) the levator veli palatini; (5) the anterior layer of the pharyngo-palatinus; (6) the palatal aponeurosis with the tensor veli palatini; (7) the glosso-palatinus palato-glossus) ; and (8) the mucous membrane on the oral aspect.
The glosso-palatinus (palato-glossus) is a cylindrical muscle extending between the soft palate and the lateral border of the tongue. Origin. — From the oral surface of the palatal aponeurosis. Insertion. — (1) The superficial layer of muscles which covers the side and adjacent part of the under surface of the tongue; (2) the transversus linguae. Structure. — At its origin the muscle forms a thin sheet, but the fibres, passing lateralward, quiclcly concentrate to form a cylindrical bundle, which passes downward beneath the mucous membrane of the pharynx
and in front of the tonsil, forming the glosso-palatine arch of the fauces. It reaches the side of the tongue at the junction of its middle and posterior thirds, and some of its fibres continue forward to join with those of the stylo-glossus and hyo-glossus, while the majority pass medially to become continuous with the transversus linguse. Nerve-supply. — From the pharjmgeal branches (plexus) of the vagus. Action. — (1) To draw the sides of the soft palate downward; (2) to draw the sides of the tongue upward and backward. The combination of these actions tends to constrict the faucial isthmus. (The origin and insertion of the glosso-palatinus as given above are often described as reversed.)
The pharyngo-palatinus (palato-pharyngeus) — named from its attachments — is a thin sheet. Origin. — (1) From the aponeurosis of the soft palate by two heads which are separated by the insertion of the levator veli palatini; (2) by one or two narrow bundles from the lower part of the cartilage of the auditory (Eustachian) tube (salpingo-pharyngeus) . Insertion. — (1) By a narrow fasciculus into the posterior border of the thyreoid cartilage near the base of the superior cornu ; (2) by a broad expansion into the fibrous layer of the pharynx at its lower part .
Cricoid cartilage
Structure. — The upper head of the muscle consists of scattered fibres which blend with the opposite muscle across the middle line; the lower head is thicker, and foUows the curve of the posterior border of the palate. The two heads with the fasciculus from the auditory (Eustachian) tube form a compact muscular band in the posterior palatine arch; the fibres mingle with those of the stylo-pharyngeus, at the lower border of the superior constrictor, and then expand upon the lower part of the pharynx. Nerve-supply. — From the pharyngeal branch (plexus) of the vagus. Action. — (1) Approximates the posterior arches of the fauces; (2) depresses the soft palate; (3) elevates the pharynx and larynx. (The origin and insertion above given are often described as reversed.)
The inferior constrictor is thick and strong. It arises from the thyreoid cartilage immediately behind the oblique hne and superior tubercle (thyreo-pharyngeus), and from a tendinous arch extending between the inferior tubercle of the thyreoid and the cricoid cartilage and also from the lateral surface of the cricoid cartilage (cricopharyngeus) (fig. 894). The fibres spread backward and medialward, the lowest horizontally, whilst those above ascend more and more obUquely, and are inserted into the fibrous raph6 of the pharynx. Some of
Near the upper border the superior laryngeal nerve and artery pierce the thyreo-hyoid membrane to reach the larynx. The inferior laryngeal nerve ascends beneath the lower border immediately behind the crico-thyreoid articulation.
The middle constrictor is a fan-shaped muscle which arises from the lesser cornu of the hyoid bone and from the stylo-hyoid Ugament (chondro-pharyngeus), and from the whole length of the greater cornu (cerato-pharyngeus). The diverging fibres are inserted into the median raphe, and blend with those of the opposite side. The lower fibres of the muscle descend, beneath the inferior constrictor, to the lower part of the pharynx; the upper overlap the superior constrictor, and reach the basilar process of the occipital bone, whilst the middle fibres run transversely (fig. 894).
The glosso-pharyngeal nerve passes downward above its upper border, the stylo-pharyngeus passes between it and the superior constrictor, and near its origin it is overlapped by the hyoglossus and crossed by the lingual artery.
The superior constrictor is quadrilateral in shape, pale, and thin (fig. 894). It arises from the lower third of the hinder edge of the median lamina of the pterygoid process and its hamular process (pterygo-pharyngeus), from the pterygo-mandibular ligament (buoco-pharyngeus), from the posterior fifth of the mylo-hyoid ridge of the mandible (mylo-pharyngeus), and from the side of the root of the tongue (glosso-pharyngeus) . The fibres pass backward to be inserted into the median raphd, the highest reaching the pharyngeal tubercle. The Eustachian tube and the levator veli palatini are placed above the superior arched border, and the space {sinus of Morgagni) between this and the basilar process, devoid of muscular fibres, is strengthened by the pharjmgeal aponeurosis, this portion of it being semilunar in shape.
The stylo-pharyngeus arises from the base of the styloid process internally. It passes downward and medialward to reach the pharynx between the superior and middle constrictors. Its fibres spread out as it descends beneath the mucous membrane. At the lower border of the superior constrictor some of its fibres join fibres of the pharyngo-palatinus (palato-pharyngeus), and are inserted mto the posterior border of the thyreoid cartilage (fig. 894); the rest blend with the constrictors. The nerve-supply of the stylo-pharyngeus is from the glosso-pharyngeal nerve.
The levator veli palatini — named from its action on the velum of the soft palate — is somewhat rounded in its upper, but flattened in its lower, half. Origin. — (1) The inferior surface of the petrous portion of the temporal, anterior to the orifice of the carotid canal; (2) the lower margin of the cartilage of the auditory (Eustachian) tube. Insertion. — The aponeurosis of the soft palate; the terminal fibres of the muscles of each side meet in the middle line in front of the m. uvulae. Structure. — Its origin is by a short tendon; the muscle then becomes fleshy, and continues so to its insertion. Nerve-supply. — From a pharyngeal branch (plexus) of the vagus. Action. — (1) To raise up the velum of the soft palate, and bring it in contact with the posterior wall of the pharynx; (2) to narrow the pharyngeal opening and to widen the isthmus of the auditory (Eustachian) tube. (According to Cleland, it closes the pharyngeal opening of this tube.)
The tensor veli palatini — named from its action on the velum of the soft palate — is a thin, flat, and narrow sheet. Origin. — (1) The scaphoid fossa of the sphenoid; (2) the angular spine of the sphenoid; (3) the lateral side of the membranous and cartilaginous wall of the auditory (Eustachian) tube. Insertion. — (1) Into the transverse ridge on the under surface of the horizontal plate of the palate bone; (2) the aponeurosis of the soft palate.
Structure. — Its belly as it descends between the pterygoideus internus and the internal pterygoid plate is muscular. On approaching the hamular process it becomes tendinous, and continues so to its insertion. A bursa is interposed between the hamular process and the tendon. The belly of the muscle is at nearly a right angle with its tendon. Nerve-supply. — From the mandibular division of the trigeminus through the tensor palati branch of the otic ganglion. Actions. — (1) Tightens the soft palate; (2) opens the auditory (Eustachian) tube during deglutition.
The m. uvulse. — so named by reason of its position in the uvula. Origin. — (1) From the aponeurosis of the soft palate and tendinous expansions of the two tensores veli palatini. Insertion.— Into the uvula. Structure. — The muscle consists of two narrow parallel strips lying on each side of the middle Une of the palate. Nerve-supply. — From the pharyngeal branch of the vagus. Action. — To draw up the uvula.
Origin of the muscles. — According to W. H. Lewis, the tensor palati is a derivative of the mandibular arch (probably split off from the pterygoid mass) ; the levator palati and m. uvulae come with the facial musculature from the hyoid arch; the glosso-palatine, stylo-pharyngeus and pharyngeal constrictors probably from the third visceral arch, in a pre-muscle mass visible in a 9 mm. embryo. The adult innervation of the pharyngeal muscles does not agree entirely with this, however. The pharyngeal muscles (as above stated) are innervated chiefly from the vagus, whereas if derived from the third arch their innervation from the glosso-pharyngeus would be expected.
Process of swallowing. — In the act of swallowing, practically aU of the muscles of the mouth, tongue, palate and pharynx are involved. By compression of the hps and cheeks, together with elevation of the tongue, the food is forced backward through the faucial isthmus into the oral pharynx. Constriction of the faucial isthmus by the glosso-palatine muscles assists in preventing a return to the mouth. By the action of the levator palati, tensor palati, and pharyngo-palatine muscles, the soft palate is retracted and tightened, with constriction of the pharyngeal isthmus, so as to prevent the passage of the food upward into the nasal pharynx. The pharynx is dra-nm upward by the stylo-pharyngeus, and the pressure produced by the pharyngeal constrictors (the contraction beginning above and extending downward) forces the food dowTiward through the laryngeal pharynx and into the oesophagus. Passage of the food into the larynx is prevented by constriction of the superior aperture of the larynx.
Vessels and nerves. — The vessels of the tonsil and the motor nerves of the various muscles have aheady been mentioned. In general, the arteries to the pharynx are derived chiefly from the ascending pharyngeal, the ascending palatine branch of the external maxillary, and the descending palatine and pterygo-palatine branches of the internal maxillary. The veins form a venous plexus between the pharyngeal constrictors and the pharyngeal aponeurosis, and also an external plexus, communicating with the pterygoid plexus above and with the posterior facial or internal jugular vein below. The lymphatic vessels pass chiefly to the deep cervical nodes, those from the upper portion (including the pharyngeal tonsil) ending partly in the retro-pharyngeal glands. The nerves of the pharynx, both motor and sensory, are derived chiefly from the glosso-pharyngeal and vagus, by way of the pharyngeal plexus.
The development of the pharynx. — The pharynx is developed chiefly (if not entirely) from the anterior end of the archenteron. In this portion of the archenteron, with the development of the branchial arches, there are formed on each side four entodermal pouches or grooves (with a rudimentary fifth), the branchial clefts (see p. 17). With further development the first pair of branchial clefts form the tympanic cavities and the auditory or Eustachian tubes; the lower portion of each second branchial cleft persists as a fossa in which a palatine tonsil is developed ; the remains of the third and fourth pairs are found on each side in the vaUecula and piriform sinus of the larynx. The origin of the pharyngeal tonsil may be observed in the ■third month of foetal life in the form of small folds of mucous membrane which, during the sixth month, become infiltrated with diffuse adenoid tissue, lymph-nodules differentiating in this toward the end of foetal life. The pharyngeal bursa, which is not a constant structure (Kilr lian), may be observed as a small diverticulum of the pharyngeal waU, closely connected with the anterior extremity of the notochord. The diverticulum develops independently of Rathke's pouch (which gives rise to the anterior portion of the hypophysis), and is also apparently distinct from Seesel's pocket.
The entire pharynx, like the associated facial region, is relatively small and undeveloped in the foetus and newborn, but develops rapidly during infancy. The development of the muscles and of the palatine tonsils has already been considered.
Variations. — Variations in the palatine and pharyngeal tonsils and in the pharyngeal bursa have already been mentioned. Remnants of the visceral clefts may persist as aberrant diver-ticula or as 'branchial fistulae' connected with the pharynx. Many additional muscles have been described, chiefly longitudinal muscles arising from the base of the cranium either by spUt•ting of those normally present, or as separate slips. A detailed description of these may be found in Poirier-Charpy's work. Abnormally extensive fusion of the posterior arches of the ■palate with the walls of the pharynx may produce a congenital stenosis of the pharyngeal isthmusi
Comparative. — The pharynx is not distinctly separated from the mouth cavity in the .lower vertebrates. It is the region containing the branchial or visceral clefts and is thus both .respiratory and aUmentary in function. The nasal pharynx, including the apertures of the •auditory tubes, becomes distinct along with the nasal cavity when the palate is formed (from the reptiles upward). In the air-breathing vertebrates, the laryngeal aperture appears in the ventral wall of the pharynx just anterior to the beginning of the cesophagus. Of the tonsils, the pharyngeal are the most primitive, being present in the roof of the pharynx in amphibia, weU-developed in reptiles, birds, and mammals (Killian). The palatine tonsils, on the other hand, are characteristic of mammals, being rarely absent, however (e. g., rat, guinea pig). From the embryological point of view, Hammar has classified the palatine ^tonsils in the various mammals under (1) the primary type (including rabbit, cat, and dog), in which the tonsil is formed from the embryonic tonsillar tubercle (described above under development of tonsil); and (2) the secondary type (including pig, ox, sheep and man), in which the tonsilt lar tubercle disappears and the tonsil is developed from the wall of the surrounding tonsillar sinus. Typical epithelial crypts (highly branched in the ox) are found only in the secondary •type. The tonsil may form a single (lymphoid) lobe (cat, pig, rabbit) or may develop typically two lobes (ox, sheep, man), separated by the intratonsillar fold. There are great variations among difl'erent species as to relative size, number and character of folds, crypts, «tc. The intimate relation of the epithelium with the underlying lymphoid tissue is characteristic and constant.
The cesophagus (figs. 895, 896) is that portion of the alimentary tract which! extends between the pharynx and the stomach. It is more constricted than the rest of the canal, being narrowest at its commencement opposite the lower border of the cricoid cartilage. It is again somewhat contracted behind the left bronchus, and at its passage through the diaphragm, which is opposite the tenth or eleventh thoracic vertebra. It has an average length of 25 cm. (varying from 20 to 35 cm.). The average distance from the rima oris to the beginning of the cesophagus is about 15 cm. In its course downward the oesophagus follows the curves of the vertebral column until it finally passes forward in front of, and slightly to the left of, the aorta to gain the oesophageal opening in the diaphragm. In addition to these curves it presents two lateral curvatures, one convex toward the left side at the root of the neck and in the upper part of the thorax, and the other concave toward the left in the lower part of the thorax where it leaves the vertebral column. It lies in the middle line at its commencement (usually opposite the sixth cervical vertebra), and again, at a lower level, opposite the fifth thoracic vertebra.
it is more rounded during life. It is closed except during the passage of food, etc.
The -peristaltic movements of the oesophagus can readily be observed by means of the Roentgen-rays. Solids often lodge a short time at the level of the arch of the aorta, but pass quickly through the cardiac orifice. A swallow of liquid, on the other hand, is usually detained at the lower end of the oesophagus (probably by sphincteric action of the cardia) for about seven seconds before passing into the stomach (Pfahler).
The oesophagus is divided into three parts: cervical, thoracic and abdominal.
Cervical portion. — The oesophagus has anteriorly the trachea, the posterior portion of the left lateral lobe of the thyreoid gland, and the left recurrent nerve, branches of the inferior thyreoid artery, and the carotid sheath. Posteriorly, it rests upon the vertebral column, the longus colli muscles, and prevertebral fascia. On its right side are placed the right carotid and right recurrent nerve; and on the left side the left inferior thyreoid vessels, left carotid artery, left subclavian, and the thoracic duct. The recurrent nerves pass upward on each side to gain the interval between the trachea and oesophagus. The left nerve, as already described, lies in front of the tube, and the right along its right border.
Thoracic portion. — The oesophagus descends in the thorax through the superior and the posterior mediastina. In the superior mediastinum its anterior relations are the trachea, with the deep cardiac plexus in front of its bifurcation, the left subclavian and carotid arteries crossing its left border obliquely, the left recurrent nerve, and the arch of the aorta. To the left are the left carotid- and subclavian arteries, the end of the arch of the aorta, and the left pleural sac. To the right it is in relation with the right vagus nerve and the right pleural sac. Posteriorly, it rests upon the vertebral column, the left longus colli muscle, and it overlaps the thoracic duct. As it enters the posterior mediastinum, it passes behind the left bronchus (or bifurcation of the trachea) and the right pulmonary artery, resting posteriorly on the vertebral column and thoracic duct. In the posterior
mediastinum it has anteriorly the pericardium, which separates it from the left atrium and a portion of the diaphragm; posteriorly it rests upon the vertebral column, accessory hemiazygos and hemiazygos veins, the right aortic intercostal arteries, the thoracic duct, and the descending aorta. To the right is the right pleural sac, the vena azygos, which it partly overlaps, and below, the thoracic duct. To the left in the upper part is the descending thoracic aorta, and, below, the left pleural sac is separated from it by a little loose areolar tissue. It is surrounded by the oesophageal ple.xus formed by the vagi nerves, and, as they emerge from the lower part of the plexus, the left vagus lies in front of the oesophagus and the right vagus behind.
Levels.
Abdominal portion. — The oesophagus lies in the epigastric region of the abdomen. Anteriorly is the left lobe of the liver. To the left the left lobe of the liver and the fundus of the stomach. To the right the caudate (Spigelian) lobe of the liver, and posteriorly the decussating fibres of the crura of the diaphragm and the left inferior phrenic artery. The abdominal portion is very short, usuallj^ not more than 2 cm. (4/5 inch) in length (see figs. 896 D, 907).
Structure. — The thick-walled oesophagus presents the four typical tunics of the alimentary canal (fig. 897). The mucosa and the muscularis are the most important, the submucosa and the external adventitia being accessory layers. The mucosa (fig. 897) is thick and strong, of reddish colour in its upper portion and more greyish below. It presents deep longitudinal folds to allow for distention, and when empty the lumen is therefore stellate in cross sections. The hning epithelium is stratified squamous. The lamina propria presents numerous papiUse, and is limited externally by a muscularis mucosm. This is a comparatively thick layer (except at the upper end) and is composed of smooth muscle fibres, longitudinally arranged.
The submucosa (fig. 897) is a thick, very loose fibrous layer connecting the mucosa with the muscularis. It contains numerous vessels and nerves, and mucous glands. The latter [gl. oesophageae] are of the racemose type, Uke those of the mouth, and are variable in number. There are also two sets of superficial glands, confined to the lamina propria, and resembling the fundus glands of the stomach. The upper set (Rtidinger-Sohaffer glands) are found in 70 per cent, of oases, occurring above the level of the fifth tracheal ring. The lower set (ojsophageal cardiac glands) form a ring around the ccsophagus just above the cardiac aperture. A few small lymph nodes also occur in the submucosa, often around the ducts of the mucous glands.
The muscularis (fig. 897) is a thick reddish tunic with two distinct layers, approximately equal in thickness. The fibres of the inner layer are arranged circularly and are continuous with the inferior constrictor above and with the obhque fibres of the stomach below. The fibres of the outer layer are longitudinal and commence above as three flattened bands: a strong anterior band arising from the ridge on the back of the cricoid cartilage, and two lateral bands blending with the fibres of the stylo-pharyngeus and the pharyngo-palatine. These all unite into a continuous layer which below passes into the muscular coat of the stomach. The upper third or fourth of the oesophagus contains e.xclusively cross-striated muscle fibres, like those of the pharynx. Below this, there is a zone of intermingled smooth and cross-striated fibres. The lower half of the cesophagus muscle is usually composed exclusively of smooth fibres.
Mucous gland
left gastric arteries. Branches pierce the wall and supply the various coats. The veins accompany the arteries. They form on the outer surface of the ccsophagus a venous plexus opening into the gastric coronary vein below and the azygos and thyreoid veins above (thus estabUshing a communication between portal and systemic veins). There are also numerous lymphatics in the cesophagus arising chiefly in the mucosa and draining into the lower deep cervical, posterior mediastinal and superior gastric nodes. The nerves form two sympathetic plexuses, the submucous and the myenteric, from which the walls are supphed as will be described later for the stomach and intestine. Branches are received from the sympathetics, and from the vagus, including the recurrent nerve.
Development. — The embryonic oesophagus is at first relatively very short, but lengthens rapidly in connection with the descent of the stomach. The upper end is still high in children, corresponding to the higher vertebral level of the larynx. The lining epithehal cells are primitively cylindrical in form, and irregular ciliated areas are found from the third foetal month up to birth (F. T.Lewis). In the embryo of about 20 mm., there is a proHferation of the epithelium, associated with the formation of vacuoles, but the lumen does not appear to be normally occluded. The primary longitudinal folds of the mucosa appear early (third month) and at the lower end seem to participate in the rotation of the stomach (F. P. Johnson). The superficial oesophageal glands appear about the fourth month (78 mm.), the deep glands at 240 mm. (Johnson). Of the muscular layers, the circular appears first (at about 10 mm.) the longitudinal shghtly later (17 mm.).
Variations. — Usually a bundle of smooth muscle connects the oesophagus with the left bronchus [m. broncho-oesophageus], and another similarly with the left mediastinal pleura [m. pleuro-oesophageus]. More rarely there are similar bands connecting with the trachea, peri-
cardium, etc. Pouch-like dilatations of the oesophagus may occur, especially in the upper part of its posterior wall or at the lower end. According to C. R. Robinson, the latter include (1) ampulla phrenica, just above the diaphragm, and (2) antrum cardiacum, in the abdominal portion of the oesophagus. Diverticula also occur, some of which may be derived from the embryonic vacuolization of the epithehum previously described, as may likewise the occasional congenital atresia. Abnormal strictures of the ccsophagus may occur, oftenest at the upper end, at the left bronchus, and near the lower end. Finally, the oesophagus may be in part either double or absent, and may communicate by fistula with the trachea.
Comparative. — The length of the oesophagus varies with the length of the neck, being shortest in fishes and amphibia where the cesophagus is not well marked off from the stomach. The lining epithelium is stratified squamous in mammals and birds, but often ciliated in lower forms. Mucous glands are absent in fishes, but occur typically m all higher forms. They are found best developed toward the lower end of the cesophagus, except in mammals, where they are usually more numerous at the upper end. Dilatations may occur normally, as in the crop of birds, which is richly supphed with glands. The musculature of the oesophagus is primitively entirely smooth (Oppel) as found in amphibia, reptiles and birds. A secondary replacement by cross-striated muscle is found to a variable extent in the majority of mammals and fishes.
The abdomen properly consists of that part of the body situated between the thorax and the pelvis. It is bounded above by the diaphragm; below, by the brim of the true pelvis; behind, by the vertebral column, diaphragm, quadratus lumborum and psoas muscles, and by the posterior portions of the ilia. At the sides it is limited by the anterior parts of the ilia and the hinder segments of the muscles which compose the anterior abdominal wall, viz., the transversus, internal oblique.
special layer of fascia.
It is customary for anatomists and physicians to divide, for purposes of description, the ventral surface of the abdomen, by means of two horizontal and two vertical lines, into nine regions (fig. 898). A complete uniformity in the use of the boundary hues marking these regional subdivisions has not as yet been attained, although the variations in the schemes used are not marked as concerns the main features. It should be borne in mind that it is necessary that the boundary lines used should be converted into planes carried through the whole depth of the abdomen and defined on the dorsal as well as the ventral surface, and that the relations defined can only be approximate, owing to the wide range of the physiological variation in the position of the abdominal contents. The nine regions or subdivisions may be outhned as follows: — The upper horizontal line or plane passes through the lowest point of the tenth costal cartilages, about 5 cm. above the umbihcus, and dorsally through the second or third lumbar vertebra. The lower
horizontal line and plane passes through the level of the anterior superior iliac spines, and dorsally about 2.5 cm. below the promontory of the sacrum. Cunningham has proposed that this hne be passed through the tuberculum cristse, therefore in a plane slightly higher than the interspinous plane. For the longitudinal hnes and planes it has been customary to run vertical hnes parallel with the mid-body line or mid-sagittal plane, and from the middle of the inguinal Ugaments. The outer border of each rectus would seem, however, preferable as a guide for these longitudinal lines and planes, which may be easily locahsed above by the lateral infra-costal furrow and below by the pubic spines, leaving thus on each side an inguinal region which includes the whole of the inguinal canal. The boundary lines here indicated may be made intelligible by a reference to fig. 898. The regions thus outhned are known as the right and left hypochondriac and epigastric regions, found above the upper horizontal line; the right and left lumbar and the umbiUcal regions, found between the two horizontal lines; the right and left
On freely laying open an abdomen from the front, the general form of the space is seen to be an irregular hexagon, the sides of which are formed as follows: — The upper two by the margins of the costal cartilages with the ensiform cartilage between; the two lateral sides by the edges of the lateral boundary; and the two lower by the two inguinal ligaments which meet at the pubes.
In this irregular hexagon the following organs can be observed without disarranging their normal position (fig. 899). Above, on the right side, under the costal cartilages, can be seen the liver, which extends from the right across the median line to a point below the left costal cartilages. Below the liver, and lying to the left side, can be seen the anterior surface of the stomach; from the lower border of the stomach the omentum extends downward, and shining through it can be seen the middle part of the transverse colon. On each side and below the
irregularly folded omentum are exposed the coils of the small intestine; in the right iliac fossa a part of the csecum appears;- and in the left iliac fossa the lower (iliac) part of the descending colon and the beginning of the sigmoid colon.
To the left of the stomach and under cover of the lower ribs of the left side the edge of the spleen may possibly be observed; and just below the edge of the liver, and about the level of the tip of the ninth rib, the gall-bladder may be seen. The dome of the urinary bladder may be noticed just behind the symphysis pubis and in the median line. The disposition of the viscera in the foetus is shown in fig. 953.
General morphology — Before taking up the various individual organs included in the abdominal and pelvic portions of the alimentary canal, a brief consideration of their general morphology is desirable. The primitive canal, as already described in the embryo (in the
Distal limb of intestinal loop
section on Morphogenesis), and as found in the lower vertebrates is a comparatively straight, simple tube extending ventral to the body axis from mouth to anus. In the abdominal region (and primitively throughout the whole trunk), the canal lies within the body cavity, which is lined by parietal peritoneum. The visceral peritoneum is reflected from the mid-dorsal line as a double layer, the ■primiiive dorsal mesentery, within which the vessels and nerves pass to the walls of the canal. Within the dorsal mesentery are also the spleen and pancreas. In the anterior (upper) region of the abdomen there is also a similar primitive ventral mesentery, which contains the liver.
The relations above mentioned are indicated diagrammatically in fig. 900, which represents a comparatively early stage in the development of the intestinal canal. The hver is already almost completely separated from the diaphragm (with which it was intimately associated in the earher septum transversum). The ventral mesentery persists in the form of (1) the gastro-
connecting the hver with the ventral body wall.
The stomach undergoes a rotation on its longitudinal axis so that its anterior border (lesser curvature) is turned to the right, and its posterior border (greater curvature) to the left (fig. 901). Thus the posterior mesentery of the stomach [mesogastrium], bulges to the left and forward, carrying with it the spleen and pancreas. The portion of the mesentery corresponding to the pancreas, and that from the spleen to the root of the mesentery, become fused with the posterior body wall. The portion of the primitive mesogastrium between the stomach and spleen persists as the gastro-splenic omentum (or ligament), while the lower portion arches forward and downward as an extensive fold, the great omentum. The portion of the peritoneal cavity left behind the stomach is termed the bursa omentalis, or lesser sac, the remainder of the peritoneal cavity being the greater sac.
Along with the pancreas, the duodenum becomes adherent to the posterior wall. The remainder of the intestine forms a loop (fig. 901), the upper portion of which forms the jejunoileum, the lower portion the large intestine. The intestinal loop rotates counter-clockwise, so that the csecum and ascending colon are carried over to the right side of the body cavity, where (with the corresponding portion of the primitive mesentery) they become adherent to the posterior body wall (fig. 901). The mesentery of the transverse colon persists (though fused partly with the great omentum, as explained later under development). The descending colon becomes displaced to the left side, and (together with its mesentery) becomes adherent to the posterior wall of the abdomen. The mesentery of the sigmoid colon usually persists (in part), whUe that of the rectum is obhterated. Through these modifications of the peri-
FiG. 901. — Diagrams Illustrating the Development of the Great Omentum, Mesentery, ETC. A, Earlier Stage; B, Later Stage. bid, caecum; dd, small intestine; dg, yolli-stallc; di, colon; du, duodenum; gc, greater curvature of the stomach; gg, bile duct; gn, mesogastrium; k, point where the loops of the intestine cross; mo, mesocolon; md, rectum; mes, mesentery; wf, vermiform appendix. (McMurrich after Hertwig.)
be more fuUy discussed later.
Under certain rare conditions, the developmental process is modified so as to produce a situs inversus, which may be partial or complete, involving both thoracic and abdominal viscera. Under these circumstances, the viscera are transposed, the right and left sides being reversed.
THE PERITONEUM
The peritoneum, as has been shown, is a serous membrane which lines the cavity of the abdomen from the diaphragm to the pelvic floor, and invests or covers to a varying extent the viscera which that cavity contains. Viewed in its very simplest condition, it may be regarded as a closed sac, the inner surface of which is smooth, while the outer surface is rough and is attached to the tissues which surround it.
In the male subject the peritoneum forms actually a closed sac; but in the female its wall exhibits two minute punctures, which correspond to the openings of the Fallopian tubes. That part which lines the walls of the abdomen is termed the parietal peritoneum; that which is reflected on to the viscera is the visceral peritoneum. The disposition of the peritoneum may first be studied by noting
The first section to be described shows the peritoneum in its simplest condition. This is a transverse section through the body, at about the level of the upper surface of the fourth lumbar vertebra, and therefore about the site of the umbilicus (fig. 902).
Fig. 902. — Diagram of Cross-section of the Abdomen, Showing the Peritoneal Belations AT THE Level OF THE Umbilicus. A 0, Aorta. AS. COL., Ascending colon. DES. COL., Descending colon. MES., Mesentery. M. COL., Descending mesocolon. »S/, Small intestine. V.C., Vena cava inferior.
to the left, it lines the side of the abdomen, until it reaches the descending colon. This it covers, as a rule, in front and on the sides, though occasionally it forms a mesocolon. Then it passes over the bodies of the vertebrae with the large vessels upon them, and leaves the back of the abdomen to run forward and enclose the small intestine, returnuig again to the spine. The two layers thus form the mesentery, having between them a middle layer [lamina mesenterii propria] containing the terminal branches of the superior mesenteric vessels. It then passes over the right half of the posterior abdominal wall, covering the ascending colon in front and at the sides only (unless there be a mesocolon), and then passes on to the side and front of the abdomen to the point from which it was first traced.
In tracing the peritoneum in a section of the body opposite the stomach (fig. 903), on a level with the first lumbar vertebra, its course becomes more complicated and difficult to follow.
In the section already given the peritoneum as a simple closed sac can be readily conceived; but at the level now exposed the serous membrane has been so introverted that there appear to be two sacs, one leading from the other, and known respectively as the greater and the lesser sac of the peritoneum. They communicate through the epiploic foramen (of Winslow) . The le.sser sac [bursa omentahs] is situated behind the stomach, so that on first opening the abdomen no trace of it is to be seen. It extends downward [recessus inferior] between the layers of the great omentum (though this part of the lesser sac is largely obliterated by adhesion
in the adult). It extends upward [recessus superior] beiiind tlie caudate lobe of the liver. The vestibule [vestibulum bur.sse omentalis] is the portion which lies just behind the lesser omentum, and communicates with the greater sac through the epiploic foramen. In general, the lesser sac is Umited anteriorly by the liver, stomach, and omenta; posteriorii/ by the posterior abdominal wall, and below, behind the great omentum, by the transverse meso-colon. Its disposition on vertical section is shown in fig. 904.
The epiploic foramen (foramen of Winslow) (figs. 903, 906) is situated just below the liver; it looks toward the right, and will readily admit one or two fingers. It is bounded superiorly by the caudate lobe of the liver; inferiorly, by the duodenum (pars superior); posteriorly, by the vena cava; and anteriorly by the right margin of the gastro-hepatic or lesser omentum, containing the structures passing to and from the hver. Starting at the epiploic foramen, the lesser sac will be found to turn to the left.
If, now, the peritoneum be viewed in a transverse section of the body at the level named, viz., through the first lumbar vertebra, it will be found that the section has probably passed through the epiploic foramen (fig. 903). Starting at the front of the abdomen and- going to theright, the peritoneum is seen to line the anterior abdominal wall, to pass over the side of the abdomen, and to cover the front of the right kidney; it then extends on to the vena cava, when it becomes a part of the lesser sac; then along the back of the lesser sac, over the aorta and pancreas, which separate it from the vertebral column ; next it reaches the anterior of the two internal surfaces of the spleen internal to the hilus. Here it meets with another layer of peritoneum, and helps to form the gastro-splenic ligament [lig. gastrolienale]. Leaving the spleen, it changes its direction forward and to the right, and runs to the stomach, forming the posterior, layer of the gastro-splenic hgament; it covers the posterior surface of the stomach, and leaves its mesial border (lesser curvature) to form the posterior layer of the lesser omentum, and then passes upward and to the right to the liver. In this transverse section it is only seen passing on the right margin of the lesser omentum, where it forms the anterior boundary of the epiploic foramen. Here it bends sharply around the omental margin enclosing the hepatic vessels continuing to the left as the anterior layer of the lesser omentum; and then passing to the left reaches the stomach, which it covers in front. It then forms the anterior layer of the gastro-
splenic ligament, and once more reaches the spleen. It passes right around the spleen to the back of the hilus, where it is reflected on to the left kidney as the lieno-renal hgament (fig. 903). Hence the peritoneum passes along the side and front of the abdomen to the point from which it started. In this section the liver is so divided as to appear separated from all connection with the other viscera and the abdominal wall, and to be surrounded by peritoneum.
The course of the peritoneum in a longitudinal section of the body will now be considered (fig. 904). Starting at the umbilicus and passing downward, the peritoneum is seen to line the anterior abdominal wall. Before reaching the pelvis it covers also the urachus, the deep epigastric arteries, and obliterated hypogastric arteries, which form ridges beneath it. For some little way above the os pubis the peritoneum is loosely connected with the abdominal wall, a circumstance which is made use of in supra-pubic cystotomy. Moreover, as the distended bladder rises from the pelvis it can detach the serous membrane to some extent from the anterior abdominal wall. In extreme distension of the bladder the peritoneum may be lifted up for some 5 cm. vertically above the symphysis. On reaching the OS pubis it is reflected on to the upper part of the bladder, covering it as far back as the base of the trigone; thence it is reflected on to the rectum, wihch it covers in front and at the sides on its upper part, rarely forming a distinct mesorectum. Between the bladder and rectum it forms in the male the recto-vesical pouch. The mouth of this pouch is bounded on either side by a crescentic fold, the plica semilunaris. In the female the peritoneum is reflected from the bladder on to the uterus, which it covers; it then extends so far down in the pelvis as to pass over the upper part of the vagina behind; thence it extends to the rectum. The peritoneum which invests the uterus is reflected laterally to form the broad ligaments. The fold between the vagina and rectum forms the recto-vaginal pouch, or pouch of Douglas. The membrane has now been traced back to the spine.
Following it upward, the sigmoid colon wifl be found to be completely covered by peritoneum, a mesocolon attaching the gut to the abdominal wall (shown in fig. 905). A little higher up in the median line the peritoneum passes forward, to enclose the small intestine, and, returning to the spine, forms the mesentery (fig. 904). It now passes over the third part of the duodenum to the pancreas, from which point it again passes forward to form the lower layer of the transverse mesocolon. It invests the transverse colon below and partly in front, and then leaves it to pass downward to take part in the great omentum. Running downward some distance, it returns and forms the anterior layer of the omentum. On reaching the stomach it goes over the anterior surface, and at the upper border forms the anterior layer of the lesser or gastro-hepatic omentum, which extends between the stomach and the liver. It invests the inferior surface of the liver in front of the transverse fissure, and, turning over its anterior border, covers the upper surface. At the posterior limit of the upper surface it leaves the liver and goes to the diaphragm, forming the superior layer of the coronary ligament. It covers the anterior part of the dome of the diaphragm, and, once more reaching the anterior abdominal wall, can be followed to the umbilicus, where it was first described. This completes the boundary of the greater sac. On reference to the diagram (fig. 904) the student might be led to suppose that the two sacs are quite separate. This, of course, is not the case; but in a longitudinal section of the body made anywhere to the left of the epiploic foramen (foramen of Winslow), it is impossible to show the direct connection between the two sacs. (See fig. 905.)
The peritoneum has only been traced in this longitudinal section so far as it concerns the greater sac. It now remains to follow upon the same section (fig. 904) such part of the membrane as forms the lesser sac. The peritoneum here will be seen to cover the posterior surface of the stomach; thence from the lesser curvature it runs upward to the liver, forming the posterior layer of the lesser or gastro-hepatic omentum. It reaches the liver behind the transverse fissure. It covers only a part of its posterior surface (caudate lobe), and is reflected on to the diaphragm, forming the lower layer of the coronary ligament. It now goes downward over the posterior part of the dome of the diaphragm to the spine, separated from the latter by the great vessels. On reaching the anterior border of the pancreas it passes forward, and forms the upper layer of the transverse meso-colon. It then covers the upper half of the transverse colon, and, descending, forms the innermost layer of the great omentum. (The inner layers of the great omentum are usually fused in the adult, however, thus obliterating this portion of the lesser sac.) It now ascends, and, arriving at the greater curvature of the stomach,
passes on to its posterior wall. At this point its description was commenced. The general relations of the greater and the lesser sac are also evident in fig. 905 showing the hnes along which the parietal peritoneum is reflected from the posterior abdominal wall as the visceral peritoneum, forming the various mesenteries and covering the various abdominal organs.
The precise manner in which certain organs — such as the hver, the caecum, the duodenum, and the kidneys — are invested by peritoneum is described in the accounts of those viscera. To such accounts the reader is referred for a description of the many 'ligaments' (such as those of the bladder and liver) which are formed by the peritoneum.
The great omentum. — As is evident from its development, the great omentum [omentum majus] is formed of four layers of peritoneum, though this is quite impossible to demonstrate in an adult, the individual layers having become adherent.
them with a heat-economising covering of fat. It is nearly quadrilateral in shape, and is variable in extent. In fig. 904 the great omentum is shown to be connected with the greater curvature of the stomach, on the one hand, and the transverse colon, on the other. Originally it extended backward above the transverse colon and mesocolon to the posterior abdominal wall. The line along which it fuses with the transverse colon and mesocolon during development is shown in fig. 904.
Mr. Lockwood has made some investigations on the lengths of the transverse meso-colon and great omentum in thirty-three cases. In twenty, under the age of forty-five, only one subject had a great omentum long enough to be drawn beyond the pubic spine; in five, the omentum reached as far as the pubes. In the cases beyond forty-five years it was the exception rather than the rule to find an omentum which could not be puUed beyond the lower Umits of the abdomen.
The lesser omentum [omentum minus] consists of a double layer of peritoneum extending between the stomach and the liver. If the two anterior layers of the great omentum are traced upward, they are seen to enclose the stomach, and then
join together again at the lesser curvature to form the lesser omentum (fig. 904). It is connected above with the portal (transverse) fissure and the fissure for the ductus venosus; below, with the lesser curvature of the stomach; the left extremity encloses the oesophagus; the right border contains the hepatic vessels and is free, forming the anterior boundary of the epiploic foramen (see fig. 906).
The lesser omentum is divided into two parts. The portion connecting the portal fissure of the hver with the first part of the duodenum, and enclosing the root structures of the liver, is called the hepalo-duodenal ligament [fig. hepatoduodenale]. The portion of the lesser omentum connecting the lesser curvature of the stomach with the fissure of the ductus venosus is the gastro-hepatic hgament [lig. hepatogastricum].
THE STOMACH 1151
oesophagus. This is the gastr o-phrenic ligament. A strong fold of the membrane also extends from the diaphragm (opposite the tenth and eleventh ribs) to the splenic flexure of the colon, and is knoM'n as the phreno-colic (costo-colic) hgament [lig. phrenicolienale]. (See figs. 905, 906.)
Minute anatomy. — The peritoneum, like all serous membranes, consists of two layers; a lining layer composed of simple squamous epithelium (mesothelium), and an underlying layer of fibrous connective tissue. The latter is highly elastic, and denser in the parietal than in the visceral layer. It often contains fat. In mesenteries and similar structures, the connective tissue is usually very scanty, except surrounding the vessels and nerves. Ruptures often occur in the omenta, which thus become fenestrated in structure. The visceral peritoneum is usually closely attached to the organs for which it forms the outer serous tunic, but the parietal peritoneum is often loosely attached to the adjacent wall by a fatty subserous layer [tela subserosa]. Smooth muscle occurs frequently in the various peritoneal folds.
The peritoneal cavity contains normally a very sUght amount of watery fluid, which serves to lubricate the smooth peritoneal surface and thus to ehminate friction between adjacent surfaces during the movements of the alimentary canal.
Vessels and nerves. — The peritoneum is in general somewhat sparsely supphed with bloodvessels from various adjacent trunks. Lymph-vessels also occur, but they probably do not connect directly with the peritoneal cavity by stomata (as is found in the frog and as claimed by some to occur in man). They communicate with the lymphatics of neighbouring i-egions. The nerves are also comparatively scarce. They are partly of sympathetic origin (vasomotor), and partly sensory nerves from the intercostal (7th to 12th), and lumbar nerves. The sensory nerves are more frequent in the parietal peritoneum and end in the connective tissue, either freely or in special end-organs (varying from simple end-bulbs to Pacinian corpuscles).
Development. — The principal features in the development of the peritoneum have already been mentioned in the section on Morphogenesis and in the remarks on the general morphology of the intestinal canal (p. 19). Further details will be included later under the development of the intestine, etc.
Variations. — Variations in the form and relations of the peritoneum are exceedingly common, and are most commonly of developmental origin. Variations in the form and relations of the various abdominal organs necessarily involve corresponding modifications in the peritoneum. The diaphragm may be incomplete!}' formed, leaving the peritoneal cavity in communication with the pleural, or more rarely the pericardial cavity. The primitive dorsal mesentery of the intestine [mesenterium commune] may persist unmodified (in about 2 per cent, of adults), or the various secondary changes may be inhibited at any stage. Thus the'stomach or the intestinal loop may fail, either wholly or partly, to undergo their characteristic rotations. The adhesions of the various mesenteries may be incomplete, or they may be more extensive than usual. For example, the sigmoid mesocolon may be more or less completely obliterated by adhesion, and numerous unusual peritoneal pockets or hgamentous bands may be formed in this way in various localities. Variations thus due to extensions of the normal developmental process are sometimes difficult to distinguish from pathological adhesions caused by peritonitis.
Comparative. — As previously mentioned, the primitive body cavity in vertebrates extends throughout the trunk region. In the oyclostomata, this primitive relation persists, the pericardial cavity remaining in communication with the general body cavity. In all higher forms, however, the pericardial cavity becomes entirely separated. In amphibia the lungs he in the general (pleuroperitoneal) body cavity; in the reptiles and birds, they are partially separated; but a complete separation of the pleural cavities occurs only with the formation of the definite diaphragm in mammals.
The formation in the peritoneal cavity of a complete dorsal mesentery, and an incomplete ventral mesentery (in the hepatic region) is typical for all classes of vertebrates. Slight modifications in the form of the mesenteries depend chiefly upon the diiJerent degrees of comple.xity in the development of the various parts of the intestinal tract. The marked changes associated with extensive secondary adhesions of the primitive peritoneal structures are found only among the higher mammaha, especially in man.
The stomach [ventriculus ; gaster] is a dilation of the alimentary canal succeeding the oesophagus. In the stomach the food is mixed with the gastric juice and reduced to a viscid, pulpy liquid, the chyme [chymus], which undergoes a certain amount of digestion and absorption before passing into the duodenum.
The stomach (figs. 906, 907) is a somewhat pear-shaped organ located in the upper, left side of the abdominal cavity. It presents a body [corpus ventricuh], with an enlarged upper end or fimdus, on the right side of which is the cardia, the aperture communicating with the oesophagus. The body of the stomach is extremely variable in form, as will be explained later, but is in general divisible into a more expanded upper two-thirds, the cardiac portion [pars cardiaca], which is nearly vertical, and a more constricted lower third, the pyloric portion [pars pylorica], which tm-ns horizontally toward the right. The pyloric portion often presents toward its lower end a slight, variable dilation, the antrum pylori,
succeeded by a short constricted pyloric canal (Jonnesco) . At the lower end of this canal the pylorus forms the aperture leading into the duodenum, and contains a thick sphincter derived from the circular fibres of the muscular layer. The stomach has two borders and two surfaces. The medial (or upper) border forms the lesser curvature [curvatura ventriculi minor], which is concave (except near the pylorus) and gives attachment to the lesser omentum. The lateral (or lower) border forms the greater curvature [curvatura ventriculi major], which is convex, and gives attachment to the great omentum. The curvatures separate the anterior surface [paries anterior], which faces forward and upward, from the posterior surface [paries posterior], which is placed backward and downward.
Dimensions. — The dimensions of the stomach are subject to great variation and therefore only a gross approximation can be given. The length of the lesser curvature averages about 10 cm. (7.5 cm. to 15 cm.), and that of the greater
curvature is three or four times as great. The diameter varies exceedingly according to the amount of contents. When nearly empty, it presents, especially in the pyloric portion, a narrow tubular form, with a diameter of about 4 cm. or 5 cm. (fig. 1108, Section XIII). The diameter of the pylorus, which is the narrowest point in the alimentary canal when constricted is only about 1.5 cm. It is distensible, however, as hard bodies with diameters of 2 cm. or more may readily pass through.
The average capacity of the stomach is between one and two litres, being subject to extreme individual variations. In the newborn, it averages about 30 cc. (25 to 35 cc), increasing very rapidly in the early postnatal months and reaching an average of 270 cc. at one year (Lissenko). The average weight of the adult stomach is about 135 gm.
posture, etc. It is therefore difficult to give a concise and accurate description.
The normal position of the stomach has long been disputed. It is generally recognised that the long axis is oblique, extending from above downward, forward and to the right. Some, however, especially among the older anatomists, have maintained that the gastric axis normally approaches more nearly to the horizontal type, with the pylorus but little below the cardia (approximately the position shown in figs. 915, 916). Others, especially among the more recent anatomists, have maintained that the axis of the stomach is normally more nearly vertical in position (see fig. 1125, Section XIII). The results of an extended and careful study, both in formalin-hardened bodies and by means of the Roentgen-rays in the living body, demonstrate that there is much variability in the position of the stomach. Both the horizontal and the vertical types may occur as the extremes of normal variation, but the more usual type is the intermediate oblique position. The gastric axis, however, is not straight, but somewhat curved and bent in a reverse L-shape. The larger cardiac portion is approximately vertical (especially when the trunk is in the upright posture) the smaller pyloric portion more nearly horizontal (figs. 895, 906, 918, 919). In the empty stomach, the pylorus opens into the duodenum from left to right. In distention, however, the pylorus is carried in front of the duodenum. In extreme distention, it is carried to the right and downward so as to open upward and to the left.
Pyloric canal Sulcus intermedius
In surface relation (fig. 914), the stomach lies within the left hypochondriac and the epigastric regions. Often, however, especially when distended, it extends into the umbilical and even the right hypochondriac region. When empty, it usually lies almost entirely in the left half of the body, with the pjdorus not more than 1 cm. or 2 cm. to the right of the mid-sagittal plane. When distended, the long axis of the stomach is lengthened and the pylorus is displaced 5 cm. or more to the right and downward. In distention, the stomach expands in all directions (except posteriorly) , and does not appear to rotate as is sometimes stated. The position of the stomach, especially when distended, also varies appreciably according to the posture of the body. It sags downward when the body is in the upright position, and to the right or left when the body is placed on the corresponding side. The cardia hes on the left side of the 10th or 11th thoracic vertebra, and corresponds to a surface point behind the left 7th costal cartilage about 2.5 cm. from its sternal end. The pylorus usually lies opposite the right side of the 1st lumbar vertebra, about midway between ensiform cartilage and umbilicus, or in Addison's ' transpyloric line,' midwaj' between the suprasternal notch and the symphysis pubis, when the body is recumbent; but descends to the 2d or lower in upright posture. The Jwndus corresponds to the left dome of the
diaphragm (which separates it from the lung and heart) , opposite the sixth sternocostal junction. The fundus of course rises and falls with respiratory movements of the diaphragm, the excursion being from 2 to 6 cm.
The relations of the stomach with surrounding organs are indicated diagrammatically in figs. 915 and 916. The anterior surface is in contact on the right with the left lobe of the liver, the pylorus reaching the quadrate lobe; on the left it is in contact with the diaphragm (separating it from the heart and left lung) ; and below with the anterior body wall by a triangular area of variable size. The posterior surface is in relation (separated by the lesser sac) with the pancreas, above which are areas of contact with the diaphragm, spleen, left kidney and suprarenal body; below the pancreas, the stomach is in contact with the transverse mesocolon, and through this with the transverse colon and coils of small intestine. The relation with the duodeno-jejunal angle is indicated in fig. 895. Further details concerning topography of the stomach are given in section XIII on Clinical and Topographical Anatomy.
Peritoneal relations. — The stomach is covered by peritoneum in its whole extent, except immediately along the curvatures and upon a small triangular space at the back of the cardiac orifice, where the viscus lies in direct contact with the diaphragm and possibly with the upper part of the left suprarenal gland. It is enclosed between two layers. These two layers at its lesser curvature come together to form the gastro-hepatic portion of the lesser omentum, and at the greater curvature extend downward to form the great omentum (figs. 903, 904). At the left of the oesophagus the two layers pass to the diaphragm, form-
The posterior surface of the stomach is in relation with the lesser sac (bursa omentalis), forming part of its anterior wall. The anterior surface of the stomach is in relation with the greater sac of the peritoneal cavity.
Minute anatomy. — The stomach is composed of the four typical layers of the alimentary canal — mucosa, submucosa, muscularis and serosa. The mucosa (figs. 907, 90S, and 909) is thrown into a series of coarse folds (pUcse mucosoe), chiefly longitudinal, which disappear when the stomach is distended. Along the lesser curvature, the ridges are more regular (corresponding to Waldeyer's 'Magenstrasse') and form a longitudinal grooved channel from cardia to pylorus. Upon closer examination (fig. 909) the inner surface of the mucosa presents a somewhat warty ('mammilated') appearance, due to numerous small elevated areas [areae gastricae], varying from 1 to 6 mm. in diameter. When examined with a lens, it is seen that each area is beset with numerous small pits [foveolae gastricae], separated by partitions which sometimes (especially in the pyloric region) bear villus-hke prolongations [plicae villosse]. The average number of foveolai is estimated at 87 per sq. mm., or more than 6 millions for the entire stomach (Toldt). Into each pit or foveola open 3 to 5 gastric glands. The entire surface is covered with a simple columnar mucigenous epithelium.
The relations of the mucosa in section are shown in fig. 910. The thickness of the mucosa varies, being greatest (about 2 mm.) in the pyloric region, decreasing to less than .5 mm. in the cardiac region (Kolliker). The lamina propria is crowded with glands, of which three varieties are distinguished. The cardiac glands are tubulo-racemose (chiefly mucous) glands occupying a narrow zone a few millimeters in width adjacent to the cardiac orifice. The fundic glands [gl. gastricae propriae] occupy the greater part of the stomach, and are simple (partly branched) tubular glands (fig. 910). They contain three varieties of cells— mucous cells, peptic cells, and parietal cells. The parietal cells may secrete an organic chloride compound, but the HCl of the gastric juice is formed not in the gland tubules but at the surface of
is still in dispute.
The interstitial tissue of the lamina propria contains diffuse lymphoid tissue and a few small lymph nodules, especially in the pyloric region. The muscularis mucosw is a thin sheet of smooth muscle lying just below the fundus of the glands and is composed of an inner circular and an outer longitudinal layer.
wrinkling of the mucosa according to the degree of distention.
The tunica muscularis contains three layers of smooth muscle (figs. 911, 912, and 913). The outer or longitudinal layer [stratum longitudinale] is thickest along the lesser curvature, and is continuous with the longitudinal fibres of the oesophagus and the duodenum. On the anterior and posterior walls of the antrum pylori, the longitudinal fibres form thickened bands.
Fig. 910. — Diagrammatic Section of the Stomach Wall Showing (A.) The Blood vessels, (B) the Tunics, and (C) the Lymphatics. M, Mucosa. Mi, Muscularis mucoste. S, Submucosa. I, Circular, and 0, longitudinal muscle layer. (Szymonowicz, after Mall.)
the ligamenla pylori. The middle or circular layer Istratum circulare] is continuous with the circular fibres of oesophagus and duodenum and surrounds the entire stomach. It is especially thickened in the region of the pyloric canal, at the lower end of which it forms a thickened ring-like band, the pyloric sphincter [m. sphincter pylori]. The inner or oblique layer [fibrae obliquse] is composed of fibres continuous with the deepest circular fibres of the oesophagus. They form an incomplete layer which encircles the fundus and passes obliquels' downward around the body of the stomach toward the greater curvature.
ance and the structure typical for a serous membrane.
Blood-vessels. — The stomach receives its blood-supply from many branches. From the coeliac axis there is the left gastric artery, which runs along the lesser curve from left to right, anastomosing with the right gastric branch of the hepatic. Along the greater curve run the right and left gastro-epiploic arteries, anastomosing at the middle of the border, the left being
a branch of the splenic, the right a branch of the hepatic, through the gastro-duodenal artery. The stomach also receives branches from the splenic (vasa brevia) at the fundus. The vascular arches along the curvatures of the stomach are comparable to those in the intestinal mesentery (MaU).
The blood of the stomach is returned into the portal vein. The coronary vein and pyloric vein open separately into the portal vein ; the right gastro-epiploic vein opens into the superior mesenteric, the left into the splenic.
FiG. 911. — A Dissection of the MtrscuLATURE of the Stomach. (Lewis and Stohr, after Spalteholz.) a and e, Longitudinal layer, b and d, Circular layer, c. Oblique layer. Py, Pylorus. S.I., Sulcus intermedins.
for absorption.
Lymphatics. — There is a set of nodes lying along the lesser and the pyloric portion of the greater curvature, and others at the pyloric and cardiac ends. These are entered by lymphatic vessels which, beginning in the mucous membrane (fig. 910), accompany all the gastric veins, but chiefly those of the lesser curvature. Vessels also accompany the left gastro-epiploic veins to terminate in the splenic nodes. On its wa}' to the receptaculum chyli, the gastric lymph passes through groups of nodes [lymphoglandulae pancreaticoUenales] situated above and behind the head and neck of the pancreas.
rootlets in the mucosa, is shown in fig. 910.
Nerves. — The nerves of the stomach are derived in part from the vagi (which form the motor fibres of the stomach), the right vagus descending on the posterior wall, and the left on the anterior wall. The stomach also receives sympathetic branches from the coeliac plexus, following the arteries. Small ganglia occur along both vagus and sympathetic branches (Remak). The nerves join the gangliated plexuses, myenteric and submucous, in the wall of the stomach,
general.
Development. — The stomach at first lies in the mid-sagittal plane in the cervical region. It participates in the general descent of the viscera (the cesophagus becoming correspondingly lengthened) and reaches its permanent vertebral level in the 17 mm. embryo (Jackson). In the meantime, beginning in the 7.5 mm. embryo (F. T. Lewis), a rotation of the stomach has occurred. The rotation is around the long axis, so that the anterior border (lesser curvature) is turned to the right, and the posterior border (greater curvature) to the left. The right surface therefore becomes posterior and the left anterior. During the process of descent, the pyloric end is the first to become fixed (at about 12 mm.). As the cardiac end continues to descend, it is displaced to the left, so the oblique position of the stomach is estabUshed early. The stomach is at first spindle-shaped, but the upper end begins to enlarge at about 10 mm. The fundus develops somewhat later as a locahzed outgrowth (Keith and Jones).
Fig. 914. — Outline Showing the Average Position op the Abdominal. iVisceea in 40 Bodies, on a Centimetre Scale (Reduced to .36 Natural Size). ML, anterior mid-hne EF, horizontal line half-way between pubes and suprasternal margin ("transpyloric" line), CD, line half way between pubes and line EF. (Addison.)
and its relations to surrounding organs undergo considerable change. Even in the foetus it is quite variable, but its general form and position do not differ essentially from the adult condition. Glands. — According to Johnson, in an embryo of 16 mm., the lining epitheUum shows the primitive foveols as pit-hke depressions which become elongated, forming irregular anastomosing grooves, separated by vilJus-like projections. The pits multiply and deepen, and from their bottoms the gastric glands bud off (at 120 mm.). The parietal cells appear very early in the gland fundus, but the differentiation of gland cells is still incomplete at birth.
Variations. — The great variability of the stomach in form, position and relations has already been repeatedly emphasized. These variations have been most carefully studied recently by various observers in the living body by means of the Roentgen-rays. Some of the results of study by this method are sho\vn in figs. 918, 919.
Peristalsis. — It would appear that most of the variations in the form of the stomach that have been described are merely various phases in the series of changes undergone by the stomach during the normal process of physiological digestion. The following account of these changes is based largely upon the radiographic observations of Cole. Earlier observations by various investigators upon the Uving stomach of man and lower animals (and especially the radiographic study of the cat by Cannon) have shown that the cardiac portion of the stomach is the first to become distended with food (and gas). Until a considerable degree of distention is reached, the pyloric portion usually remains a somewhat narrow contracted canal, along which distinct peristaltic contractions pass pylorusward.
Under favorable conditions, however, the peristaltic contractions may be observed to begin in the cardiac portion, although they are usually most distinct in the pyloric portion. Each individual contraction travels at the rate of about 2,5 cm. (1 inch) per second, so that it requires several seconds for a contraction to travel from fundus to pylorus. The number of simultaneous
contractions present in the stomach varies from 1 to 6 or 7, 3 or 4 being the most common. In fig. 919, a series of 10 successive radiographs show the progression in a stomach with four simultaneous individual peristaltic contractions. The peristaltic movements are further comphcated by the appearance (simultaneously in all) of successive periods of 'systole,' during which the peristaltic contractions become stronger and deeper, and ' diastole,' in which the contractions relax and become less distinct (Cole). In fig. 919, phases 1 to 6 represent the 'systole,' and 7 to 10 the 'diastole.' A 'systole' and a 'diastole' together make up a ' gastric cycle.' During the entire progress of an individual peristaltic contraction from fundus to pylorus, the number of 'cycles' appears to correspond to the number of peristaltic contractions present. Thus the figure represents a stomach of the 4-cyole type. The time required for a ' cycle ' varies widely, the average (in the 3- or 4-cycle type) being about 2 or 3 seconds.
In the earlier stages of gastric digestion the pylorus usually remains closed, but after a variable time it relaxes slightly (lumen about 3 mm. in diameter) at intervals, allowing the chyme to be spurted into the duodenum.
Thus the various constrictions often found in the formalin-hardened stomachs, and the pyloric antrum, appear to be merely transient phases of the digestive process. The 'hourglass' stomach is in many cases to be explained in this way; in others, however, the constriction is pathological and permanent. Various forms of abnormal lobulations and dilations also rarely occur.
Gastroptosis is a very common abnormality in which the body of the stomach extends vertically downward to the umbilicus, or lower, forming a sharp bend beyond which the pyloric portion turns upward to reach its termination. This form is especially common in women, due to tight lacing.
Fig. 919. — Serial Radiographs Taken at Short Intervals, Showing Diastole (Phases 7-10) and Systole (Phases 1-6), and the Progression toward the Pylorus op a Four-cyclBjType of Gastric Peristalsis. Fundus of the stomach not shown. (Cole.)
Comparative. — The primitive stomach is perhaps merely a receptacle for food, true'digestive glands being absent in many of the fishes. The vertebrate stomach is a dilated sac of variable form, but is typically somewhat looped, with cardiac and pyloric segments. In birds, there is a peculiar arrangement, correlated with the absence of teeth. The stomach is divided into an
THE DUODENUM
anterior glandular proventriculus, and a posterior muscular gizzard with a homy lining serving to grind the food. The mammalian stomach is the most variable in form and structure which are correlated with the method and character of alimentation. The cardiac end of the stomach is often hned to a variable extent with a prolongation of the oesophageal stratified squamous epithelium. The three kinds of glands, cardiac, fundic and pyloric, are typically present. In general, the stomach is larger and more complicated in herbivora than in carnivora. Instead of being a single sac, the stomach may be more or less divided into chambers. An incomplete division into cardiac and pyloric portions is so common that it may be considered typical. The most extreme specialization is found in the ruminants. In these the stomach has four chambers, the first two of which, however, are expansions of the oesophagus.
THE SMALL INTESTINE
The small intestine [intestinum tenue] extends from the pylorus to the ileocsecal orifice, and occupies most of the abdominal cavity below the liver and stomach. It is a cylindrical tube whose diameter decreases from about 4 cm. above to about 2.5 cm. at the lower end. Its length, when removed from the body and measured fresh, averages about 7 metres (23 ft.) ; but when formalinhardened in situ, the length (which is probably nearer that during life) is only about 4 metres. The length does not seem to vary according to sex, height or weight in the adult, but it is said to be relatively longer in the child.
The duodenum is the first part of the small intestine, and is very definite in position and extent. It is firmly attached to the posterior abdominal wall, being almost entirely retroperitoneal. It is the widest part of the small intestine, the
Superior mesenteric i
average width being 4 cm. or more, and is also the shortest segment, being only about 25 cm. in length. In general, it is somewhat C-shaped, the concavity enclosing the head of the pancreas (figs. 920, 921, 922).
Parts. — For convenience of description, the duodenum is divided into the following parts: (1) the first or superior portion [pars superior] which is short (5 cm. or less), leading from the pylorus and forming the superior flexure [flexura duodenalis superior]; (2) the descending portion [pars descendens], about 7 or 8 cm. in length, which receives the bile and pancreatic ducts and joins the inferior portion at the inferior flexure [flexm-a duodenalis inferior]; and (3) the inferior portion [pars inferior], which is again subdivided into (a) transverse portion [pars horizontaHs], about 10 cm. long, which usually ascends slightly and passes gradually into (b) the ascending portion [pars ascendens], 2 or 3 cm. long, terminating in the duodeno-jejunal flexure [flexura duodenojejunalis].
Position and relations. — As shown in fig. 914, the duodenum usually lies chiefly in the lower part of the epigastric region, only the inferior (transverse) portion extending into the umbilical region. All but the terminal (ascending) portion of the duodenum lies to the right of the mid-line.
The superior portion usually lies at the level of the first lumbar vertebra (or the disk below). It is covered anteriorly, and to a variable extent posteriorly, by a prolongation of the peritoneum from the corresponding surfaces of the stomach. It is somewhat freely movable. When the stomach is empty, it extends from the pylorus almost horizontally to the right and backward. As the stomach becomes distended, however, the pylorus is carried to the right and downward for a variable distance, and the position of the superior part of the duodenum is correspondingly altered.
Superiorly it is in contact with the hver (quadrate lobe) and the neck of the gall-bladder and forms the lower boundary of the epiploic foramen; anteriorly, with the liver and (often) the transverse colon; inferiorly and posteriorly, with the head of the pancreas below, and with the common bile duct, hepatic vessels and portal vein above.
The second or descending portion of the duodenum extends along the right side of the first to the third lumbar vertebra. It is covered antero-laterally by peritoneum, excepting (usually) the area of contact with the transverse colon (figs. 906, 920).
Posteriorly (fig. 956) it is in contact with the right kidney, ureter and renal vessels, and below with the psoas muscle. Anteriorly (fig. 906) it is crossed by the transverse colon (the layers of the transverse mesocolon usually separated by an area of direct contact); above the colon, it may be in contact with the gall-bladder, and below the colon with coils of small intestine. The
Head of pancreas
left or medial aspect of the descending duodenum (figs. 920, 921, 922) is in contact with the head of the pancreas, and some fibres from the muscular tunic are said to become intermingled with the pancreatic lobules. Somewhat posteriorly the common bile duct descends between pancreas and duodenum, and enters the descending duodenum, in common with the pancreatic duct, about 10 cm. below the pylorus. The loop formed by the pancreatico-duodenal arteries also runs along the descending duodenum.
The third or transverse portion of the duodenum usually crosses the body of the third lumbar vertebra, ascending slightly from the right to the left side (figs. 920, 921). It is covered anteriorly with peritoneum, excepting a small space where the superior mesenteric vessels enter the root of the mesentery.
The terminal or ascending portion is covered anteriorly and laterally by peritoneum, and is in contact with coils of the ileum. To the right it is in relation with the head of the pancreas (processus uncinatus) and the superior mesenteric vessels; and posteriorly with the psoas muscle, aorta and left renal vessels. The duodeno-jejunal flexure usually lies opposite the second lumbar vertebra, and is in contact above with the inferior surface of the body of the pancreas, and the root of the transverse mesocolon.
The end of the duodenum is firmly fixed in its place by the suspensorius duodeni. This name has been given to a fibro-muscular band that contains, according to Treitz, non-striated muscular fibres, and descends to the terminal part of the duodenum from the lumbar part of the diaphragm, passing to the left of the cceliac artery and behind the pancreas. Lockwood points out that this band is continued on, after being inserted into the duodenum, between the layers of the mesentery. He suggests the name of the 'suspensory muscle of the duodenum and mesentery,' and says, 'together with the other constituents of the root of the mesentery, it forms a band of considerable strength, sufficient not only to support the weight of the intestines and mesentery, but also to resist the pressure of the descent of the diaphragm.'
In connection with this fourth portion of the duodenum, mention may be made of certain peritoneal folds and fosste which are of some surgical interest by reason of their being associated with retro-peritoneal hernia. Four such fossEE may be mentioned, namely, the superior and inferior duodenal fossa:, paraduodenal and the retroduodenal,; f osste. On drawing the terminal portions of the duodenum to the right, two triangular folds of peritoneum, the superior and inferior duodenal folds, which extend from the wall of the duodenum to the posterior abdominal wall may be observed. Each fold has a free edge. Beneath each fold is found a pouch of peritoneum, constituting the superior and inferior duodenal fossae. The former, the smaller, opens downward and is present in about 50 per cent., while the latter opens upward and is present in about 75 per cent., of the subjects examined (Jonnesco). The paraduodenal fossa (fossa of Landzert) is not often found in the adult; when present, it is situated to the left of the last part of the duodenum, and is formed by a fold of peritoneum enclosing the inferior mesenteric vein. The retroduodenal fossa is a rare form extending from below upward behind the transverse portion of the duodenum.
Interior of the duodenum. — -The interior of the first part of the duodenum is smooth. The pylorus is often somewhat invaginated, much in the same way that the uterus projects into the vagina (fig. 908). On account of this arrange-
ment fwhich renders the complete emptying of the cavity somewhat difficult) and also on account of the distensibility of this portion, it usually shows up very distinctly in radiographic pictures as a ' cap ' to the pyloric end of the stomach during digestion. In the lower portions of the duodenum, transverse ridges or folds of the mucosa appear (fig. 922) which are also apparent in radiographs occasionally. On the medial wall of the descending portion, posteriorly, about half-way down, is a more or less distinct longitudinal fold [plica longitudinahs duodeni], toward the lower end of which is a small elevation, the bile papillaj'or papilla major [papilla duodeni], upon which open the common bile duct and the pancreatic duct, either separately or by a common aperture (fig. 922). Above the papilla there is usually a prominent hood-like fold (valvula connivens), and below it a variable fold or frcenum which forms a continuation of the plica longitudinahs. About 2 cm. (.9 to 3.5 cm., Baldwin) above and in front of the bile papilla there is a second, smaller, rounded papilla minor, upon which the accessory pancreatic duct (of Santorini) ends.
THE JEJUNUM AND ILEUM
The mesenteric portion of the small intestine is divided into an upper half (or two-fifths) , the jejunum, and a lower half (or three-fifths) , the ileum. Although the character of the gut changes considerably from the upper end of the jejunum to the lower end of the ileum, the transition is gradual, and there is no definite line of demarcation. In general, the jejunum is somewhat wider, has thicker walls, is more vascular and has a more complicated mucosa. The lymphoid organs (Peyer's patches) are, however, characteristic of the ileum.
The jejunum begins at the duodeno-jejunal flexure. The first coil is variable in direction, being found (in order of frequency) as follows: (1) downward, forward and to the left; (2) directly forward and downward; (.3) to the left, then downward; (4) forward and to the right (Harman). Some further details as to the position of the various succeeding coils are given later under the development of the intestine (figs. 930, 931). While there is considerable individual variation, it is true in general that the coils of jejunum occupy the upper and left portion of the body cavity, while those of the ileuyn occupy the lower and right side, the lower portion lying in the pelvic cavity. The ileum finally passes upward over the pelvic brim to the right iliac fossa where it terminates in the ileo-csecal orifice.
The mesentery [mesenterium] is a fan-shaped fold extending from the duodenojejunal flexure to the ileo-csecal junction. It is composed of a double layer of peritoneum which encloses and supports the jejunum and ileum and their vessels, connecting them with the abdominal wall. The root of the mesentery [radix mesenterii] or parietal attachment, is only about 15 cm. long, corresponding to a line extending from the duodeno-jejunal flexure obliquely downward and to the right, across the transverse duodenum, the great vessels and the vertebral column to the ileo-csecal junction (fig. 905).
The visceral attachment of the mesentery to the intestine, corresponding to the length of the jejuno-ileum, is nearly 7 metres long, and is thinner than at the root. The loidth of the mesentery, measured from parietal to visceral attachment, varies somewhat in different parts of the canal, the average being 18 or 20 cm. (ranging from 15 to 22.5 cm.). It is narrow above (also at the lower end), but reaches its full width about 30 cm. below its upper end. Between the two peritoneal layers of the mesentery is a third layer [lamina mesenterii propria] containing the superior mesenteric vessels (arteries, veins and lymphatics) with their branches and accompanying nerves, the small mesenteric lymph-nodes (50 to 100 in number), and a variable amount of fibro-adipose connective tissue.
Minute anatomy. — The small intestine has the four typical layers, — mucosa, submucosa, muscularis and serosa (figs. 927, 928). They are, in general, somewhat similar in structure to those of the stomach (fig. 910), excepting the mucosa.
The mucosa is lined with a simple cyhndrical epithehum, underneath which is a fibrous lamina propria, limited externally by a muscularis mucosoe, as in the stomach. The muscularis mucosae sends slender muscular bundles upward into the villi. The inner surface of the mucosa (fig. 924) presents numerous coarse, closely set, transverse folds [plicaj circulares]. These are permanent, crescentic folds, involving both mucosa and submucosa, and usually extending onehalf to two-thirds of the way around the lumen. They often branch and anastomose, sometimes forming circles or spirals. The largest exceed 5 cm. in length and 3 mm. in width. The plicae
circulares are absent from the first part of the duodenum, but become well-marked in the descending portion (fig. 922). They are largest and best developed in the lower duodenum and upper half of the jejunum, below which they graduaUy become smaller (fig. 924) and disappear at the lower end of the ileum.
The digestive and absorptive surface of the small intestine is further greatly increased by multitudes of small processes, the villi (figs. 925, 927), which give the mucosa a velvety appearance. They are largest (.5 to .7 mm. in height) and most numerous in the duodenum and jejunum, where they are typically leaf-shaped, and gradually become smaller, scattered and conical in the ileum. The villi are much reduced in distention of the intestine, and may even be temporarily obliterated. Between the bases of the vilh there open short, simple tubular glands — the crypts of Lieberkuehn [gl. intestinales], whose fundus cells (of Paneth) probably secrete digestive enzymes. In the duodenum there are found, in addition, the larger tubulo-
FiG. 925. — A, Surface View op the Hardened Mucosa op the Small Intestine. (After Kolliker.) B, Side View of a Wax Reconstruction op the Epithelium in the Human Duodenum. (Huber.) i g , Intestmal gland v , Villus
racemose glands of Brunner [gl. duodenales], which occupy the submucosa, and are especially numerous in the upper portion of the duodenum. They are purely mucous in character according to Bensley, although Oppel describes granular cells, similar to Paneth cells, which may secrete digestive enzymes.
Scattered over the whole of the mucous membrane of the small intestine are numerous small lymph-nodules, the larger of which extend into the submucosa; these are the so-caUed solitary glands [noduli lymphatici solitarii]. Aggregations of lymph-nodules, known as Peyer's patches [noduli lymphatici aggregati], situated in the mucosa and submucosa, are found in the ileum especially toward the lower end (fig. 926). They are oval, from 1.2 to 7.5 cm. in length and about 1 to 2.5 cm. in breadth, and are placed in the long axis of the bowel along a line most remote from the mesentery. They are variable in number, the average being about 20 to 30.
The submucosa is in general a loose areolar layer containing vascular and sympathetic plexuses (figs. 927, 928). The muscularis is composed of smooth muscle arranged in the two typical layers, — a thinner, outer longitudinal and a thicker, inner circular, — both of which become thinner toward the lower end of the ileum. The serosa is typical in structure, the squamous epithelial covering being absent in the retroperitoneal areas of the duodenum.
Blood-supply of the small intestine. — The small intestine receives its blood from the superior mesenteric artery and a branch coming indirectly from the hepatic, the superior pancreaticoduodenal. The superior mesenteric artery runs between the layers of the mesentery and gives off six or seven relatively large branches and a variable number of smaller branches. The first two or three of the larger branches divide into an ascending and a descending branch, which join above and below with the corresponding branches of the continguous arteries, forming thus a single row of arches. From about the beginning of the second quarter of the small
Fig. 927. — Cross-section op Ileum (contracted), a, b, c, Villi, d,- Intestinal gland, e, Tunica propria. /, /., Muscularis mucosa, g, Blood-vessel, h, Submucosa. i, Circular muscle, k, Longitudinal muscle. I, Serosa, m, Subserosa. n, Aggregated lymph nodules (Peyer's patch). (Radasch.)
B, Lymphatics (after Mall). C, Nerves, based on Golgi preparations (after Cajal). m, Mucosa. mm., Muscularis mucosae, s.m., Submucosa. cm., Circular muscle, i.e.. Intermuscular connective tissue. Z.m., Longitudinal muscle, s. Serosa, c.i., Central lymphatic. n.,"Nodule. s.pl. Submucous plexus, m.pl.. Myenteric plexus. (Lewis and Stohr.)
intestine a second tier of arches, formed in a similar manner, is often noted, and below the middle of the jejuno-ileum more than two tiers of arches may be present the complexity of the arches increasing, while the size of the vessels diminishes. From the convex border of the most distally placed arches there pass to the intestine straight branches, so-called vasa recta. Near the beginning of the jejunum these are numerous and large, and have a length of about 4 cm., and are quite regular. After the first third of the intestine is passed the vasa recta become smaller and shorter, and toward the lower end of the ileum they become short and irregular and are often less than 1 cm. in length. (Dwight.) The blood is returned by means of the superior mesenteric vein, which, with the splenic vein, forms the portal. The vascular arrangement in the intestinal wall is shown in fig. 928.
The lymphatic vessels form a continuous series, which is divided into two sets — viz., that of the mucous membrane and that of the muscular coat. The lymph-vessels of both sets form a copious plexus (fig. 928). The efferent lymphatic vessels form the so-called laoteals, which pass through the mesenteric lymph-nodes, finally reaching the cisterna (receptaculum) chyli.
The nerves. — The small intestine is supplied by means of the superior mesenteric plexus which is continuous with the lower part of the cceUac (solar) plexus. The branches follow the blood-vessels, and finally form two plexuses: one (Auerbach's or myenteric) which lies between the muscular coats; and another (Meissner's) in the submucous coat. The nerve fibres are chiefly from the sympathetic, partly from the vagus.
Development of the small intestine. — As the intestine is being separated from the yolkvesicle it forms at first a relatively straight tube, and as the tube elongates there is formed a single primary loop, situated in the sagittal plane of the embryo, which loop extends into the coelom of the umbilical cord; to its summit is attached the constricted attachment of the yolkvesicle, the yolk-stalk (fig. 929). This primary loop of the intestine, as it elongates, turns on an axis, so that its caudal portion turns toward the left and its cephalic portion toward the right. We may then speak of a right and a left half of the loop. Near the top of the left half of the loop, there is noted an enlargement which marks the caecum, the greater part of the left
half of the loop forming, therefore, the large intestine, while the right half of the loop forms the small intestine. In the further growth of the loop the right half elongates more rapidly than the left half, so that the caecum is no longer found in the middle of the loop. In an embryo of the fifth week, as noted by Mall, whose account is here followed closely, 'the right half of the loop has a number of small bends in it, which are of great importance in the further development of the intestine.' These small bends or loops he has marked with the numbers 1, 2, 3, 4, 5, 6. (See figs. 929, 930, 931.) The first of these bends is primarily not clear, appearing as a portion of the pyloric end of the stomach; however, it is recognised by the fact that the ducts of the liver and pancreas terminate in it, marking it as the duodenum. The omphalo-mesenteric veins and arteries, the future superior mesenteric vessels, pass through the middle of the mesentery of the large primary loop and pass over the sixth bend or secondary loop, to which is also attached the yolk-stalk. With the elongation of the intestine these six bends or loops become accentuated and acquire secondary loops or coils, nearly all of which are still found in the ccelorn of the umbihcal cord, but even with this more complicated coiling of the intestine the six primary divisions may be clearly made out. (See fig. 929.)
The large mtestine, the left half of the large primary loop, lies in the sagittal plane of the embryo and does not grow as rapidly as the small intestine, and while this is acquiring the secondary coils, the whole mass rotates about the large intestine as an axis. 'By this process the small intestine is gradually turned from the right to the left side of the body, and in so doing is rolled under the superior mesenteric artery. This takes place while the large intestine has an antero-posterior direction and before there is a transverse colon.' (Mall.) With the return of the small intestine from the umbilical coelom to the peritoneal cavity, which occurs apparently quite suddenly and during the middle of the fourth month, the caecum comes to lie in the right half of the abdominal cavity, just below the liver; the greater portion of the remainder of the large intestine then lies transversely across the abdominal cavity as the transverse colon. The six groups of loops of the small intestine may still be recognised, the loops of the upper part
of the small intestine having roOed to the left of the superior mesenteric artery, while the loops which were formerly in the cord are found in the right side of the abdominal cavity. It is not difficult to trace these six groups of loops through the later stages of foetal life to the newborn, and thence to the adult stage. In the adult, as also through the various stages of development, loop 1 forms the duodenum. From the primary groups of coils marked 2 and 3 are developed the greater part of the jejunum, arranged in two distinct groups of loops, situated in the left hypochondriac region. The part of the intestine developed from group 4 of the primary coils passes across the umbilical region to the right upper part of the abdomen. That part developed from group 5 of the primary coils recrosses the median line to the left iliac fossa, whUe that part derived from group 6 of the primary coils is found in the false pelvis and the lower part of the abdominal cavity between the psoas muscles. (Mall.) Figs. 900, 901, 930 may serve to make clear these statements. They present what may be regarded as the normal arrangement of the small intestine, having been found 21 times in 41 cadavers examined. Variations from this arrangement occur; the great majority of such variations are, however, not of sufficient importance to require special mention.
in embryos of 13 mm. to 23 mm. a formation of vacuoles in the duodenal epithelium, which
Fig. 930. — Model Showing Course OF Intestine, Made phom Same Cadaver FROM WHICH Fig. 931 was Drawn. (MaU.)
Fig. 931. — The Usttal Position of the Intestine in the Abdominal Cavity. The numbers in the figure mark the parts which are homologous with the primary bends and groups of coils numbered from 1 to 6. (Mall.)
leads to complete temporary occlusion of the lumen. A persistence of this condition may cause permanent atresia. In the epithelium of the small intestine numerous pockets or cysts occur, which usually disappear, but may persist and form permanent diverticula or accessory pancreas. The villi begin to appear at 19 mm., first in the mucosa of the upper portion of the intestine, as localized outgrowths which become arranged in longitudinal rows. The crypts of Lieberkuehn bud off from the epithehum at 55 mm., and from those in the duodenum, the duodenal (Brunner's) glands begin to bud off at 78 mm. The plicte circulares begin to appear at the midregion of the small intestine at 73 mm. The circular muscle layer begins to appear at about 12 mm., the longitudinal at 75 mm.
Variations in the small intestine. — Although relatively fixed in position, the duodenum is quite variable in form. The C-shape previously described is the most common. When the pylorus and the duodeno-jejunal flexure are approximated, the form is nearly circular. When the two ends are more widely divergent, it approaches a U-form. Not infrequently, the inferior portion ascends abruptly from the inferior angle, giving a V-form. Finally, the terminal ascending portion may be very small or absent, in which case the duodenum approaches an L-form. Variations in the position of the various coils of the jejunum and ileum have already been discussed. The lymph-nodules, including Feyer's patches, like all lymphoid structures, are prominent during youth, but become atrophied in old age.
size, usually approaching the intestine in width and averaging 5 cm. in length (ranging from 1 cm. to 13 cm.). Its attachment to the intestine varies from 15 cm. to 360 cm. (average 80 cm.) above the caecum. It is usually attached opposite the mesentery. It may end freely, but is occasionally adherent to adjacent intestinal coils or connected with the anterior abdominal wall by a cord or band-hke process.
Other diverticula of variable size and number may occur, usually along the mesenteric border of the intestine. They may be either congenital (probably from the embryonic pockets previously mentioned) or acquired. They occur most frequently in the duodenum (found by Baldwin in 15 of 105 cases) where they are usually associated with the openings of the bile and pancreatic ducts.
The large intestine [intestinum crassum] is that part of the alimentary canal which extends between the ileum and the anus. It is divided into the following parts: Csecum, ascending, transverse, descending, and sigmoid colon, and rectum. It is so arranged as to surround the small intestine, making a circuit around the abdominal cavity from right to left (fig. 899). The caecum lies in the right iliac fossa; thence the colon passes vertically upward on the right side (ascending colon) until the liver is reached. Here it forms a more or less rectangular bend (the right colic or hepatic flexure), and then passes transversely across the belly (transverse colon) below the stomach. It then reaches the spleen, where it makes a second sharp bend (the left colic or splenic flexure), and, passing vertically downward on the left side (descending colon), reaches the left iliac fossa. At this point it forms the loop of the sigmoid colon, and finally passes through the pelvis as the rectum (fig. 906). The large intestine is much larger in diameter than the small intestine, and is not so much convoluted. Excepting the dilated portion of the rectum, it is wider at the beginning than at the end. It varies in width at different parts from 3 to 8 cm. The length from the root of the appendix or tip of the csecum to the point where the meso-colon ends is, in the male, about 140 cm., and in the female about 130 cm. The average total length, including the rectum, is about 150 cm. (5 ft.). The extremes found are 100 to 200 cm.
The large intestine, in all parts except the rectum, has a peculiar arrangement of its walls, which gives it a very different appearance from the small intestine. It is sacculated, and the sacculations [haustra] are produced by the gut having to adapt its length to three shorter muscular bands which run the course of the intestine. These bands, which are about 12 mm. wide and 1 mm. thick, aie really the longitudinal fibres of the muscular wall, which are chiefly collected along three lines (fig. 935). One band [taenia mesocolica], corresponding to the attachment of the mesocolon, is posterior on the transverse colon, and postero-median on the ascending and descending colons. A second band [taenia omentalis] is anterosuperior on the transverse colon, elsewhere postero-lateral. The third band [taenia libera] is free; it is inferior on the transverse colon, anterior elsewhere. All these bands start on the caecum at the vermiform process, and spread out to form a uniform layer on the rectum. Between the sacculations are semilunar folds [plicae semilunares coli], which involve the entire thickness of the intestinal wall, forming crescentic ridges of the mucosa which project into the lumen (figs. 932, 935) . Along the free surface of the colon, especially near the taeniae, are numerous small appendages [appendices epiploicae], which are pouches of peritoneum containing fat (fig. 906).
The caecum. — The caecum [intestinum caecum] is a cul-de-sac forming the first part of the large intestine. It is defined as that part of the colon which is situated below the entrance of the ileum. Its breadth is about 7.5 cm., and its length about 6 cm. (Fig. 932).
There is usually a more or less well-marked constriction opposite the ileocaecal orifice marking the boundary between caecum and colon. The caecum itself also frequently presents a constriction dividing it into two sacculations.
It lies in the right iliac fossa, and is usually situated upon the iHo-psoas muscle, and so placed that its apex or lowest point is just projecting beyond the medial border of that muscle (figs. 899, 906). It is usually entirely enveloped in peritoneum, and is free in the abdominal cavity, but more or less attached in about 10 per cent, of all cases. The apex of the caecum usually corresponds to a point a
little to the medial side of the middle of the inguinal ligament. Less frequently the caecum will be found to be in relation with the iliacus muscle only; or the bulk of it will lie upon that muscle, while the apex rests upon the psoas. In a number of cases the caecum is entirely clear of both psoas and iliacus muscles, and hangs over the pelvic brim, or is lodged entirely within the pelvic cavity. Sometimes the caecum may pass even to the left of the median line of the body. This part of the colon is liable to considerable variation.
Its variations in form may be described under four types:
1. The foetal type is conical in shape, the appendix arising from the apex, and forming a continuation of the long axis of the colon. The three muscular bands which meet at the appendix are nearly at equal distances apart (fig. 933, A). When the cascum is empty and contracted it tends to approach this type.
2. The second form is more quadrilateral in shape than the last; the three bands retain their relative positions; the appendix appears between two bulging saccuU, instead of at the summit of a cone (fig. 933, B).
3. In the third type, that part of the caecum lying to the right side of the anterior band grows out of proportion to that part to the left of the band. The anterior wall becomes more developed than the posterior, so that the apex is turned so much to the left and posteriorly that it nearly meets the ileo-cajcal junction. A false apex is formed by the highly developed part to the right of the anterior band. This is the usual caecum found (fig. 933, C).
4. In the fourth type, the development of the part to the right of the anterior band is excessive, while the segment to the left of the band has atrophied. In this form the anterior band runs to the inferior angle of junction of the ileum with the ciecum. The root of the appendix is posterior to that angle. There is no trace of the original apex, and the appendix appears to spring almost from the ileo-cscal junction (fig. 933, D.)
The ileo-csecal valve. — The ileo-caecal valve [valvula coli] is situated at the entrance of the ileum into the large intestine at the upper border of the caecum, on the posterior aspect and toward the medial side (fig. 932). The valve usually lies nearly opposite the middle of a line from the anterior superior iliac spine (left) to the umbilicus. The ileum passes from below upward and toward the right, and terminates with a considerable degree of obliquity. The valve is formed by two lip-like folds projecting into the large intestine, the upper [labium superius], and the lower [labium inferius]. They are a little oblique. The opening between them takes the form of a narrow transverse slit about 1.2 cm. in length. At the ends of the slit the valves unite and are prolonged at either end as a ridge [frenulum valvula; coli] partially surrounding the intestine.
Villi cover that surface of the folds looking toward the ileum; the surface toward the large intestine is free from villi. In the formation of this valve the longitudinal muscular fibres pass across from the ileum to the large intestine without dipping down between the two layers of each fold. The circular muscular fibres, on the other hand, are contained between the mucous and submucous layers which form these folds.
Subcsecai fossa
Ileo-caecal fossae. — About the caecum, and especially in the vicinity of the ileocaecal junction, are certain fossae collectively known as the ileo-caecal fossae. Two only appear to be fairly constant, although a third is now and then present.
The first, the superior ileo-cmcal or ileo-colic fossa, is formed by the passage across the junction of the caecum and ileum of the anterior csecal artery, a branch of the ileo-cohc artery, which produces a fold of peritoneum [plica ileocolica] limiting a pouch. It is on the anterior aspect of the ileo-colic junction, and the pouch opens downward (figs. 906, 934). It is present in about one-third of all cases.
The second fossa is not quite so simple. If the caecum be turned upward so as to expose its posterior surface as it lies in situ, and if the appendix be drawn down so as to put its mesentery on the stretch, a peculiar fold will be found to join that mesentery (fig. 934). This fold arises from the border of the ileum opposite the insertion of its mesentery. It then passes over the ileo-caecal jimction on its inferior aspect, is adherent to the caecum, and finaUy joins the surface of the mesentery of the appendix. This fold is peculiar in the absence of any visible vessels, and is often known as the 'bloodless fold of Treves.' Between it and the appendix there is an almost constant fossa, the inferior ileo-eoeeal fossa. It is usually large, admitting two fingers, and occurs in nearly 85 per cent, of all cases. It is bounded on one side by the smaU intestine, and on the other by the ctecum. The appendix is occasionally found in the fossa.
development. It is sometimes small and insignificant; in other cases it reaches a large size. It may be so rotated that the ileum passes behind the colon and opens on the right side. The posterior part has been seen much more developed than the anterior, so that the ileum has entered from the front, and the appendix has come off from the anterior wall. The c^cum may remain undescended, and be found just under the liver or in the vicinity of the umbihcus. In case the rotation of the embryonic intestinal loop fails to occur (which rarely happens) the csecum may remain permanently upon the right side. If the normal process of adhesion fails to occur, the caecum and colon, along with the small intestine, may remain suspended from the mid-dorsal line by the primitive mesenleriuw. commune. Or any of the intermediate stages of partial adhesion may persist.
The vermiform process. — Attached to what was originally the apex of the caecum is a narrow, blind tube, the vermiform process [processus vermiformis] or appendix. It comes off at a variable distance (usually about 2.5 cm.) below the ileo-csecal valve on the postero-medial aspect of the csecum, though sometimes from the lower end of the caecum, or elsewhere. On the interior, at the point where it joins the caecum (fig. 932), there is a sUght inconstant valve [valvula processus vermiformis]. The appendix joins the caecum at the point where the three
Tffinia omeatalis Circular
taeniae meet, and the anterior taenia forms the best guide to this point. In the adult, the average length of the appendix is between 8 cm. and 10 cm., the extremes being 2 cm. to 25 cm. It is usually much twisted and coiled upon itself. Its direction is most frequently downward toward the pelvic cavity, or upward and medialward behind the ileum in the direction of the spleen. It occasionally turns lateralward, or more rarely upward behind the caecum.
The vermiform process does not have a true mesentery, but usually (in about 90 per cent, of cases) is provided with a falciform fold [mesenteriolum] of peritoneum, continuous with the left (lower) layer of the mesentery of the ileum (figs. 906, 934).
In general outline this fold of peritoneum is triangular. In the adult it does not extend along the whole length of the tube. It is, in fact, too short for the appendix, and it is this that accounts for the twisted condition of this process. Along the free margin of the fold runs a branch of the ileo-coUc artery (fig. 934).
The ascending colon. — The ascending colon [colon ascendens] (figs. 906, 914) extends in the right lumbar (lateral abdominal) region from the caecum to the inferior surface of the liver, lateral to the gall-bladder, forming there the right colic [flexura coli dextra] or hepatic flexure. Its average length is about 20 cm. (or somewhat less when measured in site). It is covered by peritoneum in front and on the side (fig. 902), but in a certain proportion of cases (26 per cent, according to Treves) this part of the large intestine is connected with the posterior wall of the abdomen by a meso-colon (usually very short) and is therefore surrounded by peritoneum. Connected with the ascending colon is sometimes found a fold 'of
peritoneum, extending from the right side of the gut to the abdominal wall at a little above the level of the highest part of the iUac crest. It forms a shelf upon which rests the extreme right margin of the liver. It might be called the sustentaculum hepatis.
The ascending colon is in relation behind with the right kidney, and the iliacus and quadratus lumborum. In front are some of the coils of the ileum (fig. 899), separating it from the anterior abdominal wall.
The transverse colon. — The transverse colon [colon transversum], smaller in diameter than the ascending, extends from the lower surface of the liver to the spleen. Its average length is from 40 to 50 cm. It describes an arch with its convexity forward and downward. It crosses through the umbilical region from the right hypochondrium to the left hypochondrium (figs. 899, 906, 914).
In the majority of cases the superficial part of the colic arch — as seen before the viscera are disturbed — is either in whole or in greater part above a straight line drawn transversely across the body between the highest points of the iliac crest. In about one-fourth of all cases it lies, in whole or in greater part, below this line.
Certain remarkable bends are sometimes formed by this part of the bowel. The bending is always in the same direction, namely, downward, and is usually abrupt and angular. The apex of the V or U-shaped bend thus formed may reach the pubes. This bend appears to be due to two distinct causes: namely, longcontinued distention, on the one hand, and congenital malformation on the other.
The transverse colon is in relation above with the liver and gall-bladder, the stomach, and at its left extremity with the spleen. The second portion of the duodenum passes behind it. Below are the coils of the small intestine. It is almost completely surrounded by peritoneum, being connected with the posterior abdominal wall (chiefly the anterior border of the pancreas) by the transverse mesocolon. This is usually lacking on the right of the mid-line, however, where the colon crosses the descending duodenum and the head of the pancreas (fig. 905).
The descending colon [colon descendens] is 25 cm. to 30 cm. in length (less when in situ) and extends from the spleen to the pelvic brim (figs. 906, 914). It is more movable than the ascending colon and is also narrower. At its beginning it is usually connected with the diaphragm, on a level with the tenth and eleventh ribs, by a fold of peritoneum, the phreno-colic ligament [lig. phrenicocolicum] (or sustentaculum lienis, from the fact that it supports the spleen). The bend between the transverse colon and descending colon is called the left colic or splenic flexure [flexura coli sinistra]. The descending colon is situated in the left hypochondriac, lumbar and iliac regions (fig. 906). Its relations to the peritoneum are the same as obtain with the ascending colon, that is, it is covered in front and on the sides. A mesocolon is met with oftener on this side than on the light, occurring in 36 per cent, of all cases (Treves) (see fig. 902). It is found especially in the lower part of the descending colon, in the iliac fossa. This portion, extending from the iliac crest to the brim fsuperior aperture) of the pelvis, is sometimes described as a separate segment, the iliac colon (Jonnesco).
The descending colon is covered anteriorly by coils of small intestine; posteriorly it is in contact with the lower part of the left kidney, the quadi atus lumborum, iliacus and psoas muscles. It terminates by crossing medialward over the psoas muscle and the external iliac vessels to join the sigmoid colon.
The sigmoid colon [colon sigmoideum] or pelvic colon, extends from the descending colon to the rectum (figs. 906, 914). It includes what was formerly described as the 'sigmoid flexure' and also the 'first portion' of the rectum. These together form a single loop which cannot conveniently be divided into parts.
the sigmoid mesocolon ceases, opposite the second or third sacral vertebra.
The loop when unfolded describes a figure that may be compared to the capital omega. The average length of this sigmoid colon is about 40 cm. The normal position of the loop is not in the left iliac fossa, but wholly in the pelvis. The most common disposition of it may now be described. The sigmoid (pelvic) colon begins about midway between the lumbo-sacral eminence and the inguinal (Poupart's) ligament. It descends at first along the left pelvic wall, and may at once reach the pelvic floor. It then passes more or less horizontally and transversely across the pelvis from left to right, and commonly comes into contact with the right pelvic wall. At this point it is bent upon itself, and, passing once more
toward the left, reaches the middle line and joins the rectum. It will lie, therefore, in more or less direct contact with the bladder (and uterus in the female), and may possibly touch the caecum. It is very closely related with the coils of small intestine that occupy the pelvis, and by these coils the loop is usually hidden. In about 90 per cent, of cases, the sigmoid colon lies entirely within the true pelvic cavity. In the remainder, it loops upward for a variable distance toward the umbilicus, a position normally found in infancy.
The sigmoid colon is attached to the abdominal and pelvic wall by the sigmoid mesocolon, so that it is quite surrounded by peritoneum. The line of attachment of this mesocolon is as follows : It usually crosses the psoas in a slight cm've upward so as to pass over the iliac vessels at or about their bifurcation. The curve ends at a point either just to the medial side of the psoas muscle, or between the psoas and the middle line, or, as is most frequently the case, just over the bifurcation of the vessels. From this point the line of attachment proceeds vertically
down, taking at first a slight curve to the right. Its course is to the left of the middle line, while its ending will be upon that line, about the second or third sacral vertebra. The sigmoid mesocolon measures from 3 to 8.7 cm. in width — i. e., from the parietes to the bowel, — at the widest point.
When a descending mesocolon exists, it joins that of the sigmoid colon. There is often no mesocolon over the psoas, the gut being adherent to that muscle. In connection with the sigmoid mesocolon is often found a fossa or pouch of peritoneum, known as the intersigtnoid fossa [reeessus intersigmoideus]. This pouch is formed by the incomplete adhesion of the
primitive mesocolon to the posterior abdominal wall. It is generally found over the bifuication of the iUao vessels. The pouch is funnel-shaped, and the opening looks downward and to the left. It varies in depth from 2.5 to 3.7 cm., and is rarely the seat of the sigmoid hernia.
The rectum. — The rectum, according to the BNA nomenclature, is recognised as a division separate from the large intestine. The term rectum is now limited to that portion of the bowel below the mid-sacral region, where the mesocolon ceases. It is divided into two portions: the first extends downward and forward, in front of sacrum and coccyx, to the level of the pelvic floor ; the second portion (the anal canal) extends from this point downward and backward to the anus (figs. 937, 938).
The upper or first portion of the rectum is about 10 cm. long, and is concave forward [fiexura sacralis] except at the lower end where it curves backward and downward [flexura perinealis] to join the second portion. The lower part of the first portion often presents a dilation [ampulla recti], due to accumulation of faeces. This part is sometimes described as the infra-peritoneal portion of the rectum proper.
Anteriorly, the rectum is in contact with coils of ileum and, in the male, with the trigone of the bladder, the vesiculse seminales, ductus deferentes, and posterior aspect of the prostate (fig. 937). In the female, it is in contact anteriorly with the vagina and the cervix uteri (fig. 938). Posteriorly, it is in contact with the sacrum, coccyx and ano-coccygeal body.
THE RECTUM 1177
The peritoneum is reflected anteriorly from the rectum to the bladder in the male (recto-vesical pouch) and to fornix of the vagina in the female (recto-vaginal pouch). In the newborn, the peritoneum reaches to the base of the prostate (Symington). On the posterior surface of the gut, there is no peritoneum below a point about 12.5 cm. from the anus. Thus the peritoneum at the upper end of the rectum entirely surrounds the gut. Lower down it covers only the sides and anterior wall, and lower still the anterior wall only, where it is reflected upon the bladder or vagina.
The second portion of the rectum, or anal canal [pars analis recti] is from 2.5 cm. to 3.5 cm. in length. From the lower end of the first portion, it turns at right angles downward and backward, passing through the pelvic floor, and ending at the anus. It is entirely below the peritoneum, and is surrounded by the two sphincter muscles (figs. 936, 937).
Anteriorly is the bulb of the urethra and the posterior margin of the urogenital trigone in the male (fig. 937), while in the female it is separated from the vestibule and the lower part of the vagina by the 'perineal body' (fig. 938). Posteriorly it is connected with the tip of the coccyx by the ano-coccygeal body. Laterally it is in contact with the margins of the levatores ani, which act as an acoessory_ sphincter, and help to support the ampulla recti.
The anus. — The anus is the aperture by which the intestine opens externally. During life it is contracted by the sphincters, so as to give the surrounding skin a wrinkled appearance. Around the lower part of the rectum and anus certain muscles that are connected with its proper function are situated. They are the internal sphincter, the levator ani, and the external sphincter. The levator ani and external sphincter will be found described in the section on Musculature. The internal sphincter is a thickening of the circular fibres of the intestine, situated around the second portion or anal canal. It forms a complete muscular ring, 2 to 3 mm. thick, and is composed of non-striated muscle.
The rectum differs from the rest of the colon in having smoother walls and no appendices epiploicse. At the upper end of the rectum, the taenia libera and taenia omentalis join to form a broad band which spreads out, covering the entire anterior aspect of the rectum. Similarly the taenia mesocolica spreads out upon the posterior aspect. Thus the rectum has a complete longitudinal muscle layer, which, however, is thicker anteriorly and posteriorly than laterally. It sends a bundle of fibres to the coccyx [m. recto-coccygeus]. Below, the longitudinal layer passes between the two sphincters and breaks up into numerous bundles which are interwoven with the external sphincter and levator ani, some of them terminating in the circumanal skin.
Its mucous membrane is thicker than that of the rest of the large intestine. Certain folds, chiefly longitudinal in direction, are seen in the lax state of the tube, which disappear when distended, but Houston had described three permanent oblique transverse folds [plicae transversales recti] (fig. 936), containing bundles of non-striated muscle-cells, which project into the lumen of the tube: one is on the right at the level of the reflection of the peritoneum from the rectum; and two are on the left, one above and one below the right fold. That upon the right side is the largest and most constant, and its muscular bundle is sometimes called the sphincter tertius. It is located about 7.5 cm. above the anus. These folds, like the corresponding semilunar folds of the colon, when well marked involve the entire wall.
The mucous membrane of the upper portion of the anal canal presents a series of vertical folds known as rectal columns [columnae rectales] (columns of Morgagni), containing bundles of non-striated muscle longitudinally arranged. These columns become more prominent as they extend downward. Just above the anus each two adjacent columns are united by an arch-hke fold of mucous membrane, these folds forming what are known as the anal valves, while the small fossse behind them are known as the rectal sinuses. The area below the valves and extending to the anus is termed the annulus hcemorrhoidalis (fig. 936). This is lined by a modified skin, while the area above the valves forms a transition to the typical mucosa of the rectum.
Minute structure of the large intestine. — In general, the large intestine has the four coats (fig. 939) — mucosa, submucosa, muscularis, and serosa — characteristic of the alimentary canal. The mucosa lacks the villi and plicae circulares characteristic of the small intestine. It contains many solitary lymphatic nodules, but no Peyer's patches. It differs from the stomach in the absence of foveolse, and in the presence of large numbers of mucous 'goblet cells' found both on the surface and along the numerous crypts of Lieberkuehn (which contain no cells of Paneth). The subrnucosa is much as in the small intestine. The muscularis has a continuous inner circular layer, the outer longitudinal fibres being chiefly gathered into the three bands, the teniae coh, as above mentioned. The serosa is typical, excepting extraperitoneal areas where the epithehum is lacking. The appendices epiploicae were also mentioned above.
The vermiform process, however, differs in several important respects (fig. 940). The walls are relatively thick and the lumen small. The solitary lymph nodules are closely packed or confluent (especially in young people). They occupy the greater part of the sub mucosa, and somewhat resemble the Payer's patches of the ileum. They, like all the lymphoid structures
in general, tend to become atrophied in old age. Fat cells are usually abundant in the submucosa. The muscularis presents an inner circular layer and also a thin but complete outer longitudinal layer. The serosa is typical. The lumen shows a progressive tendency to obliteration as age advances (Ribbert). This condition is never found in infancy but occurs
Fig. 940. — Transverse Section of the Human Vermiform Process. (X 20). (Stohr and Lewis, from Sobotta.) Note absence of villi and abundance of lymph nodules. F, Clusters of fat cells in submucosa. Only the inner part of the circular muscle is shown.
usually only partial) in over 25 per cent, of adults and in 50 per cent, of all cases over 50 years of age. It is, however, somewhat uncertain whether this represents a normal process. In obliteration, the glands and lymphoid nodules disappear, and the entire mucosa is transformed into an axial mass of fibrous connective tissue.
THE LARGE INTESTINE 1179
called to the transverse folds (of Houston) and the rectal columns, sinuses and valves. Just above the valves, the mucosa is transitional, the epithelium being partly stratified, and the crypts of Lieberkuehn few and scattering. Below the valves, the annulus hEemorrhoidalis is lined by a modified slcin. Hairs and sebaceous and sweat glands do not appear until just outside the anal orifice. The thickening of the circular muscle to form the internal sphincter, and the somewhat uniform disposition of the longitudinal muscle have already been mentioned, as well as the absence of a serous coat in the lower portions.
Blood-vessels. — The large intestine is supplied with blood by the branches of the superior mesenteric and inferior mesenteric arteries, while it also receives a blood-supply from the internal iliac at the rectum. The vessels form a continuous series of arches from the caecum, where the vasa intestini tenuis anastomose with the ileo-colic, the first branch of the superior mesenteric given to the large intestine.
The blood-supply of the rectum is from the inferior mesenteric by the superior ha^morrhoidal, from the hypogastric (internal ihac) by the middle haemorrhoidal, and from the internal pudic by the inferior hEemorrhoidal. The vessels at the lower end of the rectum assume a longitudinal direction, communicating freely near the anus, and less freely above.
The blood of the large intestine is returned into the portal vein by means of the superior mesenteric and inferior mesenteric veins. At the rectum a communication is set up between the systemic and portal system of veins, since some of the blood of that part of the intestine is returned into the hypogastric (internal ihac) veins. In the lower end of the rectum the veins, like the arteries, are arranged longitudinally. This arrangement is called the haemorrhoidal plexus.
The vermiform process is supphed by a special branch of the ileo-colic artery (fig. 934). This branch, the appendicular artery, crosses behind the terminal portion of the ileum (where pressure may obstruct the circulation) to enter the mesenteriolum. An accessory artery of small size also descends along the medial margin of the colon and caecum, entering the base of the appendix.
of the small intestine, so far as their relations within the intestinal wall are concerned.
The efferent lymphatic vessels in general follow the blood-vessels and pass through corresponding lymph nodes in the various regions (see p. 734). Those of the caecum and vermiform process pass through the appendicular and ileo-caecal nodes; those of the colon through mesocolic and mesenteric nodes. Those of the descending and sigmoid colons connect with the inferior mesenteric and lumbar nodes. The superior zone of the rectum is drained by lymphatics passing to the ano-rectal and inferior mesenteric nodes; the middle zone (region of rectal columns) to nodes along the three haemorrhoidal arteries; the inferior zone (anal integument) chiefly to the superficial inguinal nodes.
Development of the large intestine. — At an early stage in the development of the intestinal . canal, when this presents a single primary loop and soon after this loop has turned on its axis, there is observed on the left half of the loop, near its top, an enlargement which marks the beginning of the large intestine. With further growth this enlargement develops a lateral outgrowth on the side opposite to that to which the mesentery is attached, therefore free from the mesentery. A conical projection of the large intestine or colon beyond the place where this is joined to the small intestine is thus formed. This conical projection or pouch of the large intestine, which continues the colon somewhat beyond the insertion of the small intestine, develops into the caecum and the vermiform process. It does not present, in its further growth, a uniform enlargement. The portion nearest the colon grows in size more rapidly than the terminal portion, this difference in size becoming more apparent as development proceeds, the smaller terminal portion forming the vermiform process. On the return of the intestine to the peritoneal cavity (in embryos of about 40 mm.) the csecum lies on the right side, immediately below the liver. During the later fcetal months the caecum gradually descends into the right iliac fossa, and there is thus established an ascending colon. The caecum may, however, even in the adult, retain its embryonic position on the right side immediately beneath the liver, or may descend farther than usual.
The ascending and descending colons, the sigmoid meso-colon (in part), and the rectum with corresponding portions of the mesorectum, become adherent to the posterior body wall during the fourth and fifth fcetal months. At the same time, the posterior layer of the great omentum becomes fused with the upper (anterior) surface of the transverse meso-colon. The layer of retroperitoneal fascia corresponding to the obliterated mesocolon is shown in fig. 1005. Variations in the process of fusion give rise to numerous peritoneal variations in the adult.
foetus and infant.
In fcetuses of four to six months (length 100 mm. to 240 mm.) transitory viUi appear in the mucosa throughout the large intestine, including the vermiform process. They appear in rows, corresponding to longitudinal folds. Their early obliteration is possibly due to distention of the gut by the meconium.-' The glands bud off like those of the small intestine. Lymphoid nodules are present abundantly in the vermiform process at birth (Johnson). The circular muscular layer begins to appear in the lower part of the large intestine at 23 mm.; the tenia at 75 to 99 mm. (F. T. Lewis).
Development of the rectum and anus. — The posterior end of the primitive intestine or archenteron, designated the hind-gut, presents a terminal portion which is somewhat dilated and known as the cloaca, into the lateral and ventral portions of which open the Wolffian ducts, and from the ventral portion of which arises the allantois. The ventral portion of the cloaca, which is an entodermal structure, comes in contact with the ectoderm to form the cloacal membrane, and this forms the floor of a slight depression. For a time the cloaca or hind-gut extends for some distance caudal to the cloacal membrane, forming what is known as the post anal gut; this, however, soon disappears. Early in the development of the human embryo
when this has attained a length of about 6.5 mm., the fold which separates the cloaca and hind, gut from the allantois deepens, and folds develop from the lateral walls of the cloaca which meet and gradually separate the cloaca into a dorsal portion, which forms the rectum, and a ventral portion which forms the uro-genital sinus. This uro-rectal septum extends in its further growth until the cloacal membrane is reached, separating it into a ventral portion known as the urogenital membrane, and a dorsal portion known as the anal membrane. The anal membrane ruptures comparatively late in development, establishing thus a communication between the hind-gut (rectum) and the exterior. The mesoderm develops around the lower end of the rectum, so that the ectoderm becomes slightly invaginated and hnes the portion of the anal canal below the valves. A want of ruptui-e of the anal membrane constitutes an arrest of development known as atresia of the anus.
Variations. — The large intestine is exceedingly variable in its structure and relations, especiaUy with reference to the peritoneum — so much so that it has been found more convenient to include a consideration of the variations along with the preceding description of the individual parts. The content of faeces (and gas) is as a rule relatively greatest in the csecum, decreasing in ascending and transverse colons. The descending colon is usually empty, or nearly so, the sigmoid colon and rectum somewhat variable. The rectal ampulla is usually more dilated in women.
Comparative. — The morphology of both small and large intestines will be briefly considered here. As previously mentioned, the primitive form of intestine is a comparatively straight tube extending from stomach to anus, and connected by a primitive mesentery to the middorsal line of the body cavity. There is in many of the lower forms no clear division into small and large intestine, though the rectal region is usually more dilated, and opens into a cloaca. Diverticula often occur in the region between large and small intestine. In many fishes, numerous "caeca" occur just below the pylorus, and in others an extensive spiral valve projects into the lumen of the intestine. The absorptive and digestive surface of the mucosa is further increased by the formation of various kinds of folds, and (beginning in amphibia) of villi. Lymphoid tissue is typically present in the mucosa, often locaUzed in definite masses. Solitary nodules appear in amphibia, and Peyer's patches in birds. Tubular mucous glands occur in the lower forms, but Brunner's glands and crypts of Lieberkuehn with Paneth cells apparently only in mammals. A cmcum is usually present from the reptiles upward (double in birds), and often forms an important organ of digestion. The bile and pancreatic ducts open constantly a short distance below the pylorus. The small intestine is always longer than the large, but there is extreme variation in length among the various species. The four tunics — mucosa, submucosa, muscularis and serosa — are tjqDical for vertebrates, the muscularis consisting of inner circular and outer longitudinal smooth muscle fibres.
Among mammals, the divisions of the intestine correspond in general to those found in the human species, but there is exceedingly great variation in the relative development of the various parts. In general, the length, size and complexity of structure is relatively greatest in the herbivora (whose food is more difficult of digestion), least in the carnivora, and intermediate in the omnivora. Even in the same species, the structure of the intestine may be appreciably modified according to habitual diet. The large intestine varies, but is always shorter and wider than the small intestine. In mammals the rectum only is said to be homologous with the large intestine of lower vertebrates. The cmcum is rarely absent and is enormously developed in herbivora. It often contains large amounts of Ij'mphoid tissue, which, in pig and ox forms a so-called 'intestinal tonsil. ' The vermiform process (found typically developed in man and higher anthropoids) apparently represents a retrogressive evolutionary change in the cffical apex, although this interpretation is denied by some (Berry), who interpret the appendix as a progressive, functional lymphoid organ.
The liver [hepar] is tiie largest gland in the body. Its secretion, the bile [bills ; fel], is poured into the duodenum through the common bile duct. In addition it has important functions as a 'ductless gland' in connection with the nitrogenous and carbohydrate metabolism. In form it is a variable somewhat irregular mass, roughly comparable to a modified hemisphere occupying the upper right portion of the abdominal cavity (figs. 899, 914). It presents a convex, rounded upper or parietal aspect, which is in contact with the diaphragm and adjacent body walls, and a lower, flattened visceral surface, in contact with the abdominal viscera. When viewed from the front, it is somewhat triangular in outline, occupying the right hypochondriac, the epigastric and (slightly) the left hypochondriac regions.
Physical characters. — In weight, the liver averages about 1500 gm. (3| lbs.), but it is exceedingly variable, commonly ranging from 1000 gm. to 2000 gm. Its relative weight is also variable, averaging about 2.5 per cent, of the body in the adult male (somewhat higher in the female). Its specific gravity averages 1.056, so that the average weight of 1500 gm. would correspond to a volume of 1420 cc. Its dimensions are also quite variable. Its greatest depth (antero-posterior) averages about 15 cm., and its greatest height (vertical) is about the same. Its
width (horizontal) is about 20 cm., while its greatest length (measured obliquely from side to side) averages about 25 cm. The colour of the liver is a reddishbrown. It is firm in consistency, but friable, so that it is easily ruptured.
Umbilical fissure
chiefly to the 'uncovered area' of the coronary ligament), and narrow on the left side, where the posterior margin of the left lobe is likewise attached to the diaphragm. At the lower, left hand corner of the right lobe is a small triangular area of contact with the suprarenal body [impressio suprarenalis]. Near the mid-line
is the caudate (Spigelian) lobe, opposite the tenth and eleventh thoracic vertebral bodies, from which it is separated by the diaphragm (chiefly the right crus). On the right of the caudate lobe is the fossa lodging the vena cava (sometimes bridged over), while to the left is the fissure of the ductus venosus, giving attachment to the upper portion of the lesser omentum (relations in cross-section shown in fig. 945).
Impression for right kidney
body are shown in fig. 945. It extends downward upon the anterior abdominal wall to a variable extent in the epigastric region, including the entire area of the liver visible from the front (fig. 941). It also presents a broad area extending downward on the right side. Symington accordingly distinguishes three surfaces corresponding to the superior surface above described, viz., right surface, anterior surface and superior surface. The superior surface is related above, through the diaphragm, with the base of the right lung, the pericardium and heart, and (on the extreme left) with the base of the left lung. Where it rests upon the liver, the heart forms a shallow fossa [impressio cardiaca].
Fig. 944. — Diagram Showing Ligaments on the Dorso-inferior Aspect of the LrvER. (Lewis and Stohr.) c.l., Coronary lig. f.l. Falciform lig. g.b., Gall bladder, l.o., Lesser omentum, l.t.l., Left triangular lig. o.b., Caudate lobe, p.v., Portal vein, r.l., Lig. teres, r.t.l., Right triangular lig. v.c.i., Vena cava inf.
The inferior or visceral stxrface [facies inferior] (fig. 942) faces downward and backward. It is irregularly concave, with impressions due to contact with the underlying viscera. It is divided into three lobes, right, left, and quadrate, whose relations will be described later.
Of the borders, the anterior [margo anterior] is the best marked. It forms the inferior boundary of the triangular anterior view of the liver (figs. 899, 914, 941), and separates the superior from the inferior surface. Slightly to the left of the mid-line, it often presents a slight umbilical notch [incisura umbilicalis], where it
borders.
Surface outline. — The average position of the hver may be outlined upon the anterior surface of the body as follows (fig. 914): Locate one point on the right mid-clavicular (midPoupart) line opposite the fifth rib; a second point on the left mid-clavicular line about 2 cm. lower, in the fifth interspace; and a third point about 2 cm. below the costal arch (10th rib) on the right lateral wall. A line slightly concave upward, joining the first and second points defines the uppermost aspect of the lever. A line, strongly convex laterally, joining the first and third points, defines the right side of the liver. Finally, a third line, joining the second and third points, corresponds to the anterior border and defines the lowermost portion of the liver. This line is subject to many individual variations. In general, it is usually slightly convex downward as it crosses the epigastric region. It usually presents a slight umbilical notch, as before mentioned, and frequently a notch for the fundus of the gall-bladder, which is placed near the right mammarj' (mid-Poupart) line. The lower and right portion of the anterior border of the liver runs somewhat parallel with the infracostal margin. In the upright position, and in livers larger than usual, it extends about 2 cm. below the hypochondrium into the right lateral abdominal (lumbar) region (fig. 914). In the supine position, however, the liver recedes about 2 cm. toward the head. The liver of course participates also in the respiratory movements of the diaphragm.
Falciform lig.
Lobes and fissures. — The superior surface is divided by the falciform ligament into two areas, corresponding to a larger right and a smaller left lobe (fig. 941). On the posterior and inferior surfaces of the liver (figs. 942, 943), an H-shaped arrangement of fossae and fissures completes the demarcation of lobes. The left upright of the H [fossa sagittalis sinistra] corresponds to the prolongation of the line of attachment of the falciform ligament. It is made up of the umbilical fissure [fossa venae umbilicalis], containing the round ligament, on the inferior surface; and of the fossa ductus venosi, containing the ligamentum venosum (obliterated ductus venosus) and the upper part of the lesser omentum, on the posterior surface of the liver. This left sagittal fossa separates the left lobe of the liver from the right lobe (in the wider sense of the term). The right lobe is further subdivided by the right upright and cross-bar of the H. The right upright [fossae sagittales dextrae] is made up of the broad fossa for the gall-bladder [fossa vesicae felleae] on the inferior surface, and the broad fossa vence cavce on the posterior surface (fig. 943. These two fossae are not continuous, but are separated by a narrow strip of liver, the caudate process of the caudate lobe (fig. 942). The cross-bar of the H is formed by the transverse or portal fissure [porta hepatis], which encloses the root structures of the liver, within the lower part of the lesser omentum (fig. 942). The area anterior to the cross-bar of the H corresponds to the quadrate
lobe of the inferior surface; that posterior to the cross-bar to the caudate lobe of the posterior surface; while the remainder of the liver, to the right of the H, is the right lobe (in the narrower sense).
The right lobe [lobus hepatis dexter] makes up the greater part of the hver. Its relations on the superior and posterior surfaces have already been mentioned. On the inferior or visceral surface (fig. 942), there appears posteriorly a large concavity [impressio renalis] for the right kidney; medially a faint impression [impressio duodenalis] for the descending duodenum; and antero-inferiorly a variable area [impressio coHca] of contact with the right (hepatic) flexure of the colon. The caudate process joins the right with the caudate lobe.
The left lobe [lobus hepatis sinister] lies to the left of the left sagittal fissure and the falciform ligament. It is flattened but variable in form and size, and makes only about one-fifth of the entire liver. In children and especially in early foetal life, it is relatively much larger. At the left extremity, there is usually found in the adult liver a variable fibrous band [appendix fibrosa hepatis] representing the atrophied remnant of the more extensive gland in earlier life. In this fibrous appendix (and in other parts of the liver) the bile ducts of the atrophied liver substance persist as vasa aberrantia hepatis.
The left lobe is related superiorly, through the diaphragm, with the heart and the base of the left lung. Injeriorly (fig. 942) it presents a large concavity [impressio gastrioa] which is in contact with the anterior surface of the stomach. Above and behind the gastric impression is the rounded tuber omentale which is placed above the lesser curvature of the stomach and related, through the lesser omentum, with a corresponding tuberosity on the pancreas. To the left of the tuber omentale, and near the posterior aspect of the liver, is a small inconspicuous groove [impressio cesophagea] for the abdominal part of the oesophagus.
The quadrate lobe [lobus quadratus] lies, as before mentioned, on the inferior surface of the liver (fig. 942) in the anterior or inferior area of the H. It is in contact with the pylorus and the first part of the duodenum.
The caudate or Spigelian lobe [lobus caudatus; SpigeU] was described on the posterior surface of the liver (fig. 943). Inferiorly, the caudate lobe, behind the portal fissure, is divided by a notch into two processes. The left or papillary process [processus papillaris] is short and rounded, and lies opposite the tuber omentale. In the fcetus it is relatively much larger and ia in contact with the pancreas. The right or caudate process [processus caudatus] is of variable size, and joins the caudate with the right lobe of the hver. It is usually small and inconspicuous. In the foetus, however, it is relatively much larger, and extends downward to a variable extent behind the duodenum and head of the pancreas. In the adult, it forms the upper boundary of the epiploic foramen (of Winslow).
Peritoneal relations. — -The liver in the adult is almost entirely surrounded by peritoneum. Although it develops together with the diaphragm in the common septum transversum (as explained previously, see figs. 951,952), the peritoneum soon extends in between liver and diaphragm, so that they remain in immediate contact only in the so-called 'uncovered area.' This is an irregular area on the posterior surface of the liver (chiefly on the right lobe), the margins of which correspond to the coronary ligament (figs. 905, 944). The posterior surface of the liver is therefore chiefly retroperitoneal, excepting the caudate (Spigelian) lobe, which is in contact with the recessus superior of the bursa omentalis (fig. 905). The superior and inferior surfaces of the liver are entirely covered with peritoneum, excepting the lines of attachment of the various peritoneal ligaments, and the fossa for the gall-bladder, which is usually directly in contact with the gall bladder with no intervening peritoneum.
Ligaments. — The liver is attached by five peritoneal ligaments — coronary, right and left triangular (lateral) and falciform ligaments and lesser omentum—" and two accessory ligaments — teres and venosum.
Within this uncovered area the hepatic veins join the inferior vena cava. The coronary ligament, though somewhat irregular and variable in form, is elongated laterally and roughly quadrangular. At the four angles, the peritoneal layers come together and are prolonged into four ligaments — right and left triangular (lateral) and falciform hgaments and lesser omentum. There is often also a special prolongation of the coronary ligament downward upon the right kidney, forming the hepato-renal ligament [lig. hepatorenale]. This lies to the right of the foramen epiploicum.
The right triangular (or lateral) ligament [hg. triangulare dextrum] is a short but variable prolongation of the coronary ligament to the right and downward (figs. 905, 944) . It connects the posterior surface of the right lobe of the liver with the corresponding portion of the diaphragm.
The left triangular (lateral) ligament [lig. triangulare sinistrum] is a longer, narrower prolongation of the coronary ligament to the left (figs. 905, 944). It connects the posterior aspect of the left lobe of the hver with the corresponding portion of the diaphragm.
mesogastrium.
Its upper end is continuous posteriorly with the coronary ligament. It passes forward and downward over the superior surface of the liver. From its line of attachment to the liver (between right and left lobes) it passes forward and slightly to the left to the attachment on the anterior body wall. This attachment extends downward slightly to the right of the mid-line to the umbilicus. The lower margin of the falciform ligament is free, and encloses the roimd ligament.
The round ligament [lig. teres hepatis] is a fibrous cord representing the obliterated foetal left umbilical vein. It extends upward from the umbilicus enclosed in the lower margin of the falciform ligament.
At the anterior margin of the liver it passes backward on the inferior surface, enclosed in a slight peritoneal fold at the bottom of the fossa vense umbilicalis (sometimes bridged over by liver tissue). It ends by joining the left branch of the portal vein.
The ligamentum venosum [lig. venosum; Arantii] similarly represents the obliterated fcetal ductus venosus. It is a fibrous cord lying in the fossa ductus venosi, and e.xtends from the left branch of the portal vein upward to the left hepatic vein near its opening into the vena cava. The ligamentum venosum lies within the hepatic attachment of the lesser omentum.
The lesser omentum [omentum minus] has already been discussed in connection with the peritoneum. It represents the dorsal part of the primitive ventral mesogastrium, extending from the stomach to the liver. It includes two parts, as shown in fig. 906.
The upper and larger part forms the gasiro-hepalic ligament [lig. hepato-gastricum], connecting the liver (fossa ductus venosi) with the lesser curvature of the stomach. The upper part of this ligament is somewhat thicker, the lower part thinner and more transparent. The relations of the lesser omentum in cross-section of the body are shown in fig. 903. The lower and right portion of the lesser omentum extends beyond the pylorus and connects the portal fissure with the duodenum, forming the hepalo-duodenal ligament [lig. hepatoduodenale] (fig. 905). Its right margin forms the anterior boundary of the epiploic foramen (of Winslow). Between its layers are located the root structures of the hver, as follows: hepatic artery to the left, common bile duct to the right, portal vein behind and between. A special prolongation of the hepato-duodenal ligament frequently extends downward to the transverse colon, forming the hepato-colic ligament [lig. hepatocoHcum].
Fixation of the liver. — The liver is to a certain extent fixed in place by means of its various ligaments, and especially through the attachment of the hepatic veins to the inferior vena cava. On account of the close apposition of the liver to the diaphragm, the atmospheric pressure also helps in its support. Finally, the support of the liver, as well as of the abdominal viscera in general, is dependent to a considerable extent upon the tonic contraction of the abdominal muscles, which exerts a constant pressure upon the abdominal contents.
Blood-vessels. — The liver receives its arterial supply of blood from the hepatic artery, a branch of the coeliac, which passes up between the two layers of the lesser omentum, and dividing into two branches, one for each lobe, enters the liver at the portal fissure. The right branch gives off a branch to the gall-bladder. The liver receives a much larger supply of blood from the portal vein, which conveys to the liver blood from the stomach, intestines, pancreas, and spleen. It enters the portal fissure, and there divides into two branches. Below this fissure the hepatic artery lies to the left, the bile-duct to the right, and the portal vein behind and between the two (fig. 946). These three structures ascend to the liver between the layers of the lesser omentum in front of the epiploic foramen. At the actual fissure the order of the three structures from before backward is — duct, artery, vein.
The hepatic veins, by which the blood of the hver passes into the inferior vena cava, open usually by two large and several small openings into that vessel on the posterior surface of the gland at the bottom of the fossa venae cavoe.
Lymphatics. — The lymphatics are divided into a deep and a superficial set. The deep set runs with the branches of the portal vein, artery, and duct through the liver, leaving at the portal fissure, where they join the vessels of the superficial set. The efferent deep vessels after leaving the portal fissure pass down in the lesser omentum in front of the portal vein, through the chain of hepatic lymphatic nodes, and ultimately end in a group of nodes at the upper border of the neck of the pancreas, in which the pyloric lymphatics also terminate.
The superficial set begins in the subperitoneal tissue. Those of the upper surface consist: — (1) Of vessels which pass up, principally, in the falciform ligament and right and left triangular ligaments, through the diaphragm, and so into the anterior mediastinal nodes, and finally into the right lymphatic duct. Some lymphatics of the right triangular ligament pass to the posterior mediastinal lymph-nodes and into the thoracic duct. (2) Of a set passing downward over the anterior border of the liver to the hepatic nodes in the portal fissure, and over the posterior surface to reach the superior gastric and coeliac nodes. On the lower surface, the lymphatics to the right of the gall-bladder enter the lumbar nodes. Those around the gall-bladder enter the hepatic nodes of the lesser omentum. Those to the left of the gall-bladder enter the superior gastric nodes.
Nerves. — The nerves of the liver are derived from the vagi (those from the left vagus entering from the stomach through the lesser omentum), and from the coehac plexus of the sympathetic (including right vagus branches) through a plexus accompanying the hepatic artery. The terminations, so far as known, are chiefly to the walls of the vessels and of the bile ducts.
Structure of the liver. — The liver is, for the greater part, covered by peritoneum, beneath which is found the fibro-elastio layer known as Glisson's capsule. At the portal fissure, Ghsson's capsule passes into the substance of the liver, accompanying the portal vessels, the branches of the hepatic artery, and the bile-ducts. The hver substance is composed of vascular units measuring from 1 to 2 mm., and Icnown as hver lobules. These are in part (man) separated by
a small amount of interlobular connective tissue, which is a continuation of Ghsson's capsule. In this interlobular connective tissue are found the terminal branches of the portal vessels; the hepatic artery, and the bile-ducts (figs. 947, 948). The branches of the portal vessels which encircle the liver lobules are known as the interlobular veins. From these are given off hepatic capillaries, which anastomose freely, but have in general a direction toward the centre of the lobule, and unite to form the central or intralobular veins, which in turn unite to form the sublobular veins, and these the hepatic veins. The intralobular branches of the hepatic arteries form capillaries which unite with the capillaries of the intralobular portal veins.
The liver is a modified compound tubular gland. The liver-cells are arranged in anastomosing cords and columns occupying the spaces formed by the hepatic capillaries. The bile-ducts have their origin in so-called bile-capillaries [ductus biliferi], situated in the columns of liver-cells; they anastomose freely and pass to the periphery of the lobules to form the primary divisions of the bile-ducts, and these unite to form the larger bile-ducts. The branches of the portal vessel are accompanied in their course through the liver by the branches of the hepatic artery and the bile-ducts, surrounded by extensions of Ghsson's capsule forming the so-called 'portal canals' (fig. 947). The branches of the hepatic vein are solitary, their walls are thin and closely adherent to the liver substance, whence they remain wide open on sectioning the liver.
While it is customary to describe thus the hver lobules, it would be more logical to consider as the real lobules what Mall has described as the 'portal units.' Each portal unit includes the territory supplied by one interlobular branch of the portal vein, and drained by the accompanying bile-duct. The relations of the ordinary lobules and the portal units are evident in fig. 948. The portal unit corresponds more nearly to the lobule of other glands, where the duct is in the centre of the lobule.
common bile duct.
The gall-bladder [vesica fellea], which retains the bile, is situated between the right and quadrate lobes on the lower surface of the liver. It is pear-shaped, and when full, is usually seen projecting beyond the anterior border of the liver, coming in contact with the abdominal wall opposite the ninth costal cartilage at the lateral margin of the right rectus muscle (fig. 914). It extends back as far as the portal fissure.
It measures in length, from before backward, 7 to 10 cm. It is 2.5 to 3.5 cm. across at the widest part, and will hold about 35 cc. (Ij oz.). The broad end of the sac is directed forward, downward, and to the right, and is called the fundus. The narrow end, or neck [collum vesicae fellete], which is curved first to the right, then to the left, lies within the gastro-duodenal Ugament at the portal fissure. The intervening part is called the body [corpus vesicae felleae].
PORTAL UNIT
Its upper surface is in contact with the liver, lying in the fossa of the gall-bladder. It is attached to the liver by connective tissue. The lower surface is covered by peritoneum, which passes over its sides and inferior surface, though occasionally it entirely surrounds the gallbladder, forming a sort of mesentery attaching to the liver. The lower surface comes into contact with the first part of the duodenum and the transverse colon, and occasionally with the pyloric end of the stomach or small intestine, which post mortem are often found stained with bile.
The neck of the gall-bladder opens into the cystic duct [ductus cysticus]. This is a tube about 3.5 cm. long and 3 mm. wide, which unites with the hepatic duct to form the ductus choledochus; it is directed backward and to the left as it runs in the gastro-hepatic ligament, the common hepatic artery being to the left and the right branch of the artery and portal vein behind. It joins the hepatic duct at an acute angle, and is kept patent by a spiral valve [valvula spiralis; Heisteri], formed by its mucous coat (fig. 949).
The hepatic duct [ductus hepaticus] Ijegins with a branch from each lobe, right and left (that from the left receiving also the ducts from the caudate lobe), in the portal fissure, and is directed downward and to the right within the portal fissure and the hepato-duodenal ligament, the right branch of the hepatic artery being behind and the left branch to the left. It is from 3 to 5 cm. long; its diameter is about 4 mm. Uniting with the cystic duct, it forms the common bile-duct [ductus choledochus].
The ductus choledochus or common bile-duct is about 7.5 cm. in length and 6 mm. in width. It passes down between the layers of the lesser omentum, in front of the portal vein, and to the right of the hepatic artery (fig. 946) ; it then passes behind the first part of the duodenum, then between the second part and the head of the pancreas, being almost completely embedded in the substance of the pancreas, and ends a little below the middle of the descending duodenum by opening into that part of the intestine on its left side and somewhat behind (figs. 921,
922, 957). It pierces the intestinal wall very obliquely, running between the muscular layers for a distance of about 1 to 2 cm. There is a slight constriction at its termination. The pancreatic duct is generally united with the ductus choledochus just before its termination, and there is a slight papilla at their place of opening on the mucous surface of the duodenum. This papilla is about 8 or 10 cm. from the pylorus. After the pancreatic duct has entered the bile-duct there is (in about half the cases) a dilatation of the common tube called the ampulla of Vater.
In its oblique course through the duodenal wall, the common bile duct is accompanied by the pancreatic duct, the two together usually causing the pUca longitudinalis duodeni (fig. 922). Circular muscle fibres join with bundles of longitudinal fibres at the lower part of the ducts and form a sphincter around each (fig. 950). Contraction of the sphincter probably closes the orifice of.'the common bile duct, so that (except during digestion) the bile is backed up into the gall-bladder.
Fig. 950. — Macerated Duodenal Portion op the Common Bile Duct, Showing Musculature. B, Common bile duct. TT^, Pancreatic duct (of Wirsung). iS, Tij, Sphincter fibres of Isile duct. H, Fibres of pancreatic duct. (Hendrickson.)
1. The mucosa is raised into folds bounding polygonal spaces, giving the interior a honey-* comb appearance. It is lined with columnar epithelium, and contains a few tubular mucous glands and lymph-nodules, and is hmited externally by a poorly developed muscularis mucosae. At the neck the mucous membrane forms valve-like folds which project into the interior. This layer contains an anastomosis of blood-vessels, the capillaries being most numerous in the folds of the mucosa, and a fine plexus of lymphatics.
2. The fibro-muscular coat consists of interlacing bundles of non-striated muscle and fibrous tissue not definitely arranged, the muscular bundles running longitudinally and obliquely This layer contains the principal blood-vessels and lymphatics, and also a nerve plexus.
Fig. 951. — Diagrams op the Development op the Liver. (Lewis and Stbhr.) A, The condition in a 4.0 mm.- human embryo. B, A 12 mm. pig. C, The arrangement of ducts in the human adult, c. d., Cystic duct; c. p., cavity of the peritoneum; d., duodenum; d.c, ductus choledochus; dia., diaphragm; div., diverticulum; /. I., falciform ligament; g. b., gall bladder; g. a., greater omentum; h. d., hepatic duct; ht., heart; int., intestine; li., liver; I.O., lesser omentum; to., mediastinum; on., cesophagus; p. c, pericardial cavity; p. d. pancreatic duct; ph., pharynx; p. v., portal vein; st , stomach; Ir., trabecula; v. c. i., vena cava inferior; v.v. vitelline vein; y. s., yolk sac.
The ducts consist of a fibro-muscular and a mucous layer. In the fibro-muscular layer are non-striated muscle-cells which are chiefly circular, together with white fibrous tissue and elastic fibres. The mucous layer is lined with columnar epithehum, and has manj' mucous glands. In the cystic duct the mucous membrane is raised into folds, which are crescentic in form, and directed so obUquely as to seem to surround the lumen of the tube in a spiral manner.
The development of the liver. — The relations which the liver bears to the diaphragm, to its vessels and more especially the veins, and to its so-called hgaments, may be understood by a reference to its development (figs. 951, 952). In discussing the development of the peritoneum and the mesenteries it was shown that the liver has its origin in a bud of entoderm, which grows
into the transverse septum in the region where this is attached to the ventral mesoderm of the developing intestine; and that, with further development, the transverse septum differentiates into an upper thinner portion, inclosing the Cuvierian ducts, and destined to form the diaphragm, and a lower thicker portion in which the liver develops. Shortly after the formation of the entodermal bud which forms the liver this mass of epithelium taecomes penetrated by outgrowths from the omphalo-mesenteric veins, reducing the epithelial mass to anastomosing trabeculae separated by blood-spaces forming a sinusoidal circulation. The definite hepatic lobules are not differentiated until after birth. The process of the development of the lobules is very complicated, the vascular arrangement being shifted repeatedly (Mall).
The liver rapidly enlarges, filling the upper portion of the abdominal cavity, and extending along its ventral wall to the region of the umbilicus. During the enlargement it in a measure outgrows the transverse septum, and there are developed grooves which result in an infolding of the peritoneum covering the transverse septum, and which in part separate the developing liver from that part of the septum destined to form the diaphragm_, and also from the ventral abdominal wall. These grooves appear at the sides and also ventral to the hver, but do not completely separate the liver from the diaphragm, nor do they meet in the median line. A portion of the liver, therefore, remains uncovered by peritoneum, and remains attached to the diaphragm; this area may be known as the uncovered or phrenic area of the hver. Around this area the peritoneum of the hver is reflected on to the diaphragm, forming the coronary ligament, with right and left extensions, designated as the right and left triangular hgaments. Owing 'to the fact that the grooves which develop on the sides of the liver do not meet in the median line, there persists a fold of peritoneum which attaches the Hver to the ventral abdominal
Fig. 952. — Diagram (A) : A Sagittal, Section of an Embryo showing the Liver enclosed WITHIN THE Septum Transversum; (B) AFbontal Section of the same; (C) Frontal Section of a Later Stage when the Liver has separated from the Diaphragm.
wall; this forms the falciform ligament, which divides the superior surface of the hver into a right and a left lobe. The region of the attachment of the ventral mesentery (mesogastrium) into which grows the entodermal liver bud, forms the lesser omentum. The developing liver early comes into intimate relation with the omphalo-mesenteric veins, and a little later the umbilical veins. The developmental history of these veins and their relation to the developing liver is discussed elsewhere (see Development of the Portal Vein and Inferior Vena Cava, p. 694). After birth the left umbilical vein forms the hepatic ligamentum teres, situated in the free edge of the falciform hgament. The ductus venosus likewise atrophies to form the ligamentum venosum.
The gall-bladder has its origin in a groove lined by entoderm, which appears on the ventral surface of the primitive intestine or archenteron, between the stomach and the yolk-vesicle. From the cephalic end of this groove grows out the bud destined to form the liver; the caudal end of the groove becomes gradually separated from the developing intestine to form a pouch, lined by entoderm, which forms the beginning of the gall-bladder. With further growth the attachment to the intestine of both the liver and the gall-bladder becomes narrowed to form the ductus choledochus.
During development, the liver undergoes marked changes in form and relative size. It grows with great rapidity in the embryo, its maximum relative size reaching 7 to 10 per cent, of the entire body about the third prenatal month. At this time, the hver is globular in form, the visceral surface very small, and the left lobe more nearly approaching the right in size. During the later foetal months (fig. 953) and at birth, the liver forms about 5 per cent, of the whole body. It stiU remains relatively large in infancy, but decreases to about 2.5 per cent, in the adult. From the beginning, the relative weight of the liver averages slightly higher in the female.
Variations of the liver and bile passages. — Many variations of the liver have already been mentioned. In size, both relative and absolute, it is subject to marked individual variations, as well as according to age and sex (previously described). Inform, the liver is also quite variable. There are two extreme types: (1) in which the liver is very wide, extending far over into the left hypoohondrium, but relatively flattened from above downward; and (2) in which it
extends but slightly to the left, being somewhat flattened from side to side, and elongated vertically. This type may occur as a result of tight lacing, in which the liver is frequently deformed. The part projecting below the right costal margin may form the so-called 'Riedel's lobe.' All intermediate forms between these two types occur. Its position and relations will also vary necessarily according to differences in size and shape. For example, in the wide type and also in enlarged livers, the left lobe may extend over upon the spleen, a relation which is constant during prenatal life.
There may be supernumerary fissures, dividing the hver into additional lobes, as many as 16 having been described in an extreme case (Moser). These extra fissures often correspond to fissures which are normal in other mammals. There may also be accessory lobes, usually small, and connected with the main gland by stalks. Any one of the normal lobes may be atrophied or absent. There may also be abnormal grooves on the parietal surface of the liver. Of these, there are two varieties: (1) costal grooves, due to impressions of the overlying ribs and costa! cartilages; and (2) diaphragmatic grooves, due to wrinkles in the diaphragm. These
grooves most frequently occur in females, as a result of tight lacing. The appendix fibrosa has already been mentioned. There are numerous variation in the vascular arrangements, as well as in the psritoneal relations (particularly in connection with the coronary ligament).
The bile passages are even more variable than the liver proper. The gall-bladder is variable in size and capacity (25 cc. to 50 oc. or more), as well as in its position, and relations. The fundus projects to a variable extent beyond the anterior margin of the liver so as to come into contact with the abdominal wall in a little more than half the cases, but is often retracted. The fossa of the gall-bladder is of variable depth, rarely so deep that it reaches the superior surface of the liver. The peritoneum usually covers only the sides and inferior surface of the gallbladder, but occasionally surrounds it entirely, forming a short 'mesentery.' In rare cases the gall-bladder is bilid or double, and is occasionally absent. There are numerous variations in the bile-ducts. Rarely the hepatic ducts may communicate directly with the gall-bladder. The point at which hepatic and cystic ducts unite is variable, which affects the relative lengths of these and the ductus choledochus. The latter may open into the duodenum separately, instead of with the pancreatic duct.
Comparative. — The liver arises in all vertebrates as an outgrowth of the entodermic epithelium of the intestine just beyond the stomach. In amphioxus it remains a simple saccular diverticulum, but in aU higher forms becomes a compound tubular gland. The tubular character becomes masked, however (in amniota, and especially in mammals), by the abundant anastomosis between the tubules, forming what is called a 'solid' gland. The relations with the portal venous system are constant. The liver frequently stores large quantities of fat, and may even undergo a complete fatty metamorphosis (lamprey). The colour of the liver is usually reddish-brown, but may be yellow, purple, green or even vermillion (due to bile pigments). In size, the liver is variable, but is usually relatively larger in anamniota. Among mammals, there is great variation according to diet, the liver being relatively larger in carnivora, smaller in herbivora, and intermediate in omnivora (including man). It is also relatively larger in small animals (including young and foetal stages), probably on account of their more intense metabolism. There are typically two lobes, right and left, in the vertebrate hver. These are frequently subdivided, however, especially in mammals, which often present numerous lobes.
The gall-bladder is typically present, as in man, but varies in form, size and position. It may be completely buried in the fiver. In some species it is absent, in which case the hepatic ducts open directly into the duodenum by one or more apertures. The hepatic and cystic ducts typically unite to form a common bile-duct, as in man, but there are numerous variations in the detailed arrangement of the ducts.
The pancreas (figs. 922, 954, 955, 956) is an elongated gland extending transversely across the posterior abdominal wall behind the stomach from the duodenum to the spleen. Through the pancreatic duct, opening into the descending duodenum, flows its secretion [succus pancreaticus], which is of importance in digestion. The pancreas also has a very important internal secretion.
The pancreas is greyish-pink in colour; average length {in situ), 12 cm. to 15 cm.; average weight about 80 gm. (extremes 60 gm. to 100 gm. or more); specific gravity, 1.047, which is about the same as that of the salivary glands.
In position, the pancreas lies in the epigastric and left hypochondriac regions. In form, it somewhat resembles a pistol, with the handle placed to the right and the barrel to the left. The pancreas is accordingly divided into a head, lying within the duodenal loop; a body, extending to the left; and a tail, or splenic extremity.
The head [caput pancreatis] is a discoidal mass somewhat elongated vertically and flattened dorso-ventrally. It forms the enlarged right extremity of the pancreas and lies within the concavity of the duodenum (flgs. 922, 954, 955). Its relations are as follows (figs. 954, 955, 956) : Its posterior surface is placed opposite the second and third lumbar vertebrae, and is in contact with the aorta, the vena cava, the renal veins and right renal artery. The common bile-duct is also partly embedded in this surface. Its anterior surface is crossed by the transverse colon, above which is the pyloric extremity of the stomach, and below which are coils of
Fig. 956. — Outline Showing the Average Position op the Deeper Abdominal Viscera in 40 Bodies, on a Centimetre Scale (reduced to .36 natural size). AB, anterior mid-line. EF, horizontal line half way between pubes and suprasternal margin. CD, line half way between pubes and line EF. (Addison.)
small intestine. Upon this surface are also the pancreatico-duodenal and (in part) the superior mesenteric vessels. The margin of the head of the pancreas is C-shaped, corresponding to the inner aspect of the duodenal loop, with which it is closely related. Superiorly the margin is in contact with the pylorus and first part of the duodenum; on the right, with the descending duodenum and the terminal portion of the common bile duct ; inferiorly, with the horizontal, and on the left, with the terminal ascending portion of the duodenum.
The lower and left portion of the head of the pancreas is hooked around behind the superior mesenteric vessels, forming the processus uncinatus or pancreas of Winslow (fig. 922). A groove, the pancreatic notch [incisura pancreatis], is thus formed for the vessels. The morphology of this process is explained later under development (fig. 958).
In the adult condition, the head of the pancreas is largely retroperitoneal. The only portions covered by peritoneum are (1) a small area above the attachment of the colon, and in relation with a pocket-like recess of the bursa omentalis, and (2) a small area below the transverse colon, which is in relation with coils of small intestine. The mesentery of the small intestine begins where the superior mesenteric vessels pass downward from in front of the processus uncinatus.
The junction of the upper and left aspect of the head with the body of the pancreas is called the neck. This is a somewhat constricted portion grooved posteriorly by the superior mesenteric vessels, the vein here joining with the splenic to form the portal vein (fig. 955). Anterior to the neck is the pyloric portion of the stomach. The upper portion of the neck (together with a variable area on the left end of the body) projects above the lesser curvature of the stomach. This projection [tuber omentale] is related, through the lesser omentum, with a similar tuberosity on the left lobe of the liver. The anterior aspect of the neck is covered with peritoneum of the bursa omentalis (lesser sac), and is continuous with the anterior surface of the body of the pancreas (fig. 922).
The body [corpus pancreatis] is the triangularly prismatic portion of the pancreas extending from the neck on the right to the tail on the left. Its direction is transversely to the left and (usually) somewhat upward. It is therefore usually placed at a somewhat higher level than the head, opposite the first lumbar vertebra. It presents three surfaces — anterior, posterior, and inferior — and three borders — superior, anterior, and posterior.
Of the surfaces, the anterior [facies anterior] faces forward and somewhat upward. It is covered with the peritoneum of the posterior wall of the bursa omentalis (lesser sac), and forms a slightly concave area which is in contact with the posterior surface of the stomach (figs. 904, 906). The posterior surface [f. posterior] of the body of the pancreas is flattened and retroperitoneal. From right to left it crosses the anterior aspect of aorta, left suprarenal body and left kidney. The splenic vessels also run along the posterior surface, the artery, which is above, corresponding more nearly with the superior border. The inferior surface [f. inferior] is usually the narrowest of the three. It is covered by peritoneum (continuous with the lower layer of the transverse mesocolon) and is in contact with the duodeno-jejunal angle medially and with coils of jejunum laterally.
Of the borders, the superior [margo superior] is related with the splenic artery along its whole length from its origin in the coeliac, and the posterior [margo posterior] separates posterior and inferior surfaces. The anterior border [margo anterior] is sharp and prominent. It gives attachment to the transverse mesocolon, whose upper layer (belonging to the lesser sac) is continuous with that on the anterior surface of the pancreas, and whose lower layer (belonging to the greater sac) is continuous with that on the inferior surface.
The tail of the pancreas [cauda pancreatis] is at the left extremity of the body. It is variable in form, but usually somewhat blunted and upturned. It is almost invariably in contact laterally with the medial aspect of the spleen, and inferiorly with the splenic flexure of the colon. The splenic vessels often cross from above in front of the tail of the pancreas on their way to join the spleen.
Ducts. — The pancreas has usually two ducts, the main pancreatic duct and the accessory duct. The main pancreatic or duct of Wirsung [ductus pancreaticus; Wirsungi] begins in the tail of the pancreas, and extends to the right within the body of the pancreas, about midway between upper and posterior borders, but nearer the posterior surface (figs. 922, 957). It runs a slightly sinuous course
receiving branches all along, which enter nearly at right angles. It is largest in the head of the pancreas (diameter about 3 mm.) where it turns obliquely downward. As it approaches the duodenum, it is joined by the common bile duct, the two running side by side. They pass obliquely through the wall of the duodenum for a distance of about 15 mm. (usually causing a fold of the mucosa, the plica longitudinalis duodeni). They terminate finally, usually by a common aperture, but sometimes separately, on the duodenal papilla major, as described in connection with the interior of the duodenum. The common aperture is somewhat narrow, but just preceding this the duct is frequently dilated, forming what is called the ampulla of Vater.
The accessory pancreatic duct (duct of Santorini) is nearly always present (figs. 922, 957), but variable. This duct is small, and lies within the head of the pancreas. At its left end, it usually joins the main duct in the neck of the pancreas. From here it extends nearly horizontally across to the upper part of the descending duodenum and, piercing its wall, usually ends upon the small papilla minor, about 2 cm. above and slightly ventral to the papilla major. The relations of the ducts are explained later under development.
Blood-vessels. — The pancreas receives blood chiefly from the splenic artery through its pancreatic branches, and from the superior mesenteric and hepatic by the inferior and superior pancreatico-duodenal arteries, which form a loop running around, below, and to the right of its head.
veins.
Lymphatics. — ;The lymphatics terminate in numerous glands which lie near the root of the superior mesenteric artery, above and below the neck of the pancreas. All the lymphatics drain ultimately into the cceliac glands.
the gland. The main part of the coehac plexus lies behind the gland.
Minute anatomy. — In many respects, the pancreas resembles the salivary glands in structure, hence its German name 'Bauchspeicheldrtise' ('abdominal sahvary gland'). The gland proper is racemose (or tubulo-racemose) in structure, the secreting cells characteristically granular and 'serous' in type. The thin-walled 'intercalary ducts,' often invaginated to form 'centroacinar' cells, are characteristic. The lobules are very loosely joined by areolar tissue, and there is no distinct fibrous capsule around the gland. 'The most important of the distinctive characters of the pancreas is the presence throughout the gland of numerous small interlobular ceU-masses of varied form and size — the islets of Langerhans (fig. 959). These have no ducts, but are richly supplied with blood-vessels. They are ductless glands of great importance in sugar metabolism, and their removal or disease produces diabetes. While derived embryologically from the same entodermal anlage which gives rise to the pancreas gland proper, they apparently have no direct connections with it in the adult. The question as to the possible metamorphosis of acini into islets, or vice versa, under certain conditions (e. g., hunger) in the adult has been much disputed. Bensley, however, has recently presented strong evidence against this view.
Development of the pancreas. — The pancreas has its origin in three entodermal buds, one of which (the dorsal anlage) grows from the dorsal portion of the duodenum, the other two (ventral anlages) from either side of the bile-duct. Of the two latter, only that growing from the right side of the bile-duct needs further consideration, as the other soon disappears. The dorsal anlage grows at first more rapidly than the ventral, which arises from the bile-duct. In their further growth both the dorsal and ventral anlages become lobed, these lobes dividing further to form the ducts and the alveoh of the gland. By about the end of the second month the distal end of the ventral portion comes in contact with the dorsal portion at a short distance
from the latter's connection with the duodenum. A fusion of the two portions thus takes place in this region, and at the same time there is estabhshed by anastomosis a connection between the terminal branches of the main duct of the dorsal portion — duct of Santorini — and the branches of the main duct of the ventral portion — the duct of Wirsung. With further development the duct of Wirsung develops into the main pancreatic duct, the duct of the dorsal
accessory pancreatic duct.
Thus of the adult gland, only the lower portion of the head is derived from the primitive ventral anlage, although the duct of the latter drains nearly the entire adult gland. The upper part of the head of the pancreas, and all of the body and tail are derived from the dorsal anlage; although most of its duct joins with the duct of Wirsung to form the main pancreatic duct, only a small part persisting as the accessory duct of Santorini.
Fig. 959. — Section op Human Pancreas, Magnified, Showing Several Islets of Langerhans. (Radasch.) a, Interlobular connective tissue, containing an interlobular duct, c, b. Capillary, d, Interlobular duct, e, Alveoli. /, Islet of Langerhans.
During the early stages in the development of the pancreas the entodermal buds from which it forms grow into the mesoduodenum, and later the dorsal mesogastrium. With the rotation of the stomach and the consequent change in the position of the mesogastrium and its partial fusion with the abdominal wall, the pancreas assumes a retroperitoneal position. This is illustrated by fig. 958. The head of the pancreas is involved in the rotation of the primitive
intestinal loop counter-clockwise around the superior mesenteric artery. This accounts for the position and the hook-like form of the processus uncinatus. Following this rotation, the duodenum and the head of .the pancreas become pressed backward against the posterior abdominal wall, where they become adherent, with fusion and obliteration of the primitive peritoneum. The body of the pancreas, extending mto the dorsal mesogastrium (fig. 900), is similarly caught in the pouch-like downgrowth of the latter to form the bursa omentahs (lesser sac), and is thereby carried over to the left side. When the posterior layer of the primitive bursa fold becomes fused with the posterior abdominal wall, the enclosed pancreas is likewise fixed and becomes retroperitoneal. Of these obUterated peritoneal layers of the embryo, only certain layers of fascia remain as their representatives in the adult. From the lower aspect of the pancreas downward, the posterior layer of the bursa fold becomes fused with the transverse mesocolon, so that in the adult the latter appears to arise from the anterior border of the pancreas (fig. 904).
Variations. — Aside from minor fluctuations in size and form, the variations of the pancreas are chiefly congenital and of embryonic origin. Cases of accessory or supernumerary pancreas are not rare. They are usually of small size and have separate ducts. They may occur along the wall of the duodenum, or even in the stomach or jejunum. They are perhaps m some way connected with the numerous intestinal diverticula which occur in the embryo. Divided pancreas differ from the accessory in that a mass of the pancreas becomes separated from the main gland, connected only by a duct. This occurs oftenest in the region of the tail (sometimes extending into the spleen) or of the processus uncinatus, forming what is termed a 'lesser pancreas.' Sometimes a ring of glandular tissue from the head of the pancreas surrounds the descending duodenum, forming an annular pancreas. Variations in the direction of the body are numerous; it may be horizontal, ascending or bent in various ways. These are doubtless congenital variations, as similar types have been described in the foetus (Jackson). It has been experimentally demonstrated that varying degrees of distention of the stomach and intestines affect profoundly the form of the body of the pancreas. When the stomach alone is distended, the pancreas is flattened antero-posteriorly, the inferior surface being practically obliterated. When both stomach and intestines are distended, the pancreas is flattened from above downward, and e.xtends forward hke a shelf, the posterior surface being much reduced (Jackson). Numerous variations in the ducts are easily understood from their complicated development. The accessory duct (of Satorini) is in the foetus as large as the main duct (of Wirsung), the preponderance of the latter being established later. The accessory duct in the adult may be larger than usual, and retain its primitive drainage, or even drain the entire gland in rare cases where the duct of Wirsung is absent. Or the accessory duct may be rudimentary or (rarely) absent. Similar variations occur in the main duct of Wirsung. Rarely the pancreas may open into the duodenum by three ducts, probably representing three embryonic anlages. Abnormalities of the pancreas are often associated with duodenal diverticula.
Comparative. — The pancreas, like the liver, is constant throughout the vertebrates. It always arises by budding off from the endodermal epithelium of the intestine, closely associated with the Uver. There is typically a triple anlage (rarely multiple, which is perhaps the ancestral type), with one dorsal and two ventral outgrowths. These fuse and form the adult pancreas in a variety of ways. In many of the fishes, the pancreas is very small, diffuse and inconspicuous, sometimes embedded in the liver or intestinal wall. Of the three primitive ducts, usually only two persist (as in man), but often only one, or all three (in birds). All three types occur in mammals. The islets of Langerhans arise from the epithelial pancreas anlage, and appear to be constantly present, even in the lowest vertebrates. Laguesse even considers that phylogeneticaUy they form the most primitive part of the pancreas, but this is doubtful.
References for digestive system. — General and Co7nparative: Quain's Anatomy, 11th ecL; Poirier-Charpy, Traits d'anatomie; Rauber-Kopsch, Lehrbuch der Anatomie, 9te Aufl.; Oppel, Mikroskopische Anatomie, Bd. 1-3; also 'Verdauungsapparat ' in Merkel and Bonnet's 'Ergebnisse'; Wiedersheim, Bau des Menschen. Topography: (adult) Merkel, Topographische Anatomie; (developmental) Jackson, Anat. Rec, vol. 3. Development: Keibel and Mall's Manual. Teeth: Tomes, Dental Anatomy. Tonsils: (lingual) Jurisch, Anatomische, Hefte, Bd. 47; (pharyngeal) Symington, Brit. Med. Jour. (Oct., 1910); (palatine) Killian, Archiv f. LaryngoL, Bd. 7. (Esophagus: Goetsch, Amer. Jour. Anat., vol. 10. Stomach: (structure), Bensley, Buck's Ref. Handb. Med. Sc, vol. 7 (1904); (form) Cunningham, Trans Royal Soc. Edinb., vol. 45; (radiography) Cole, Archives Roentgen Rays, 1911; also Journal Amer. Med. Assn., vol. 59. Duodenum: (diverticula), Baldwin, Anat. Rec, vol. 5. Vermiform process: Berry and Lack, Jour. Anat. and Phys., vol. 40. Rectum: Symington, Jour. Anat. and Phys., vol. 46. Liver: Mall, Amer. Jour. Anat., vol. 5. Pancreas: (islets) Bensley, Amer. Jour. Anat., vol. 12; (ducts) Baldwin, Anat. Rec, vol. 5.
Among unicellular animals the oxygen is taken up directly from the medium — water or air — in which they Hve, and the carbon dioxide given off into it. With the cells which make up the body of higher animals the principle is the same, but the interchange of gases is indirect. The blood stands as an intermediate element between the cells of the body and the medium inhabited
blood circulating in the body. The essential organs in the system are the paired lungs located in the thoracic cavity. Air is carried to and from the lungs by the trachea and bronchi, and these simple transmitting tubes are in turn put into communication with the exterior by the mediation of other organs. The latter are, however, specially constructed in adaptation to other functions in addition to those relating to respiration: the larynx for the production of the voice, the pharynx and mouth in connection with alimentation, the nasal cavity and external nose functioning in the sense of smell. (For the description of the mouth and pharynx see Section IX; for the olfactory organ see Section VIII.)
The organs of circulation are always adapted to the form of the respiratory apparatus, and among all higher animals a connection is established between heart and lungs by the pulmonary artery, which carries venous blood to the latter, and by the pulmonary veins, which convey arterial blood from the lungs to the heart, whence the aorta takes it into the general circulation.
In their origin and development the respiratory organs are closely associated with or differentiated from the beginnings of the digestive apparatus. Thus the processes of the early development of the nasal cavity and mouth are interdependent; the origin of the greater part of the larynx, the trachea and lungs is by ventral outgrowth of the entodermal canal.
THE NOSE
The external nose [nasus externus] (fig. 961), shaped like a triangular pyramid, is formed of a bony and cartilaginous framework covered by muscles and the integument of the face externally and lined within by periosteal and perichondral layers overspread by mucous membrane. At the forehead, between the eyes, is
Cellular tissue forming ala
the root of the nose [radix nasi], and from this, extending inferiorly and anteriorly, is a rounded ventral border, the dorsum of the nose [dorsum nasi], which may be either straight, convex, or concave, and which ends inferiorly at the apex of the nose [apex nasi]. The superior part of the dorsum is known as the bridge. Inferionly, overhanging the upper lip, is the base of the nose [basis nasi] which presents two orifices, the nares or nostrils, separated from one another by the inferior movable part of the nasal septum [septum mobile nasi].
The nostril of man is remarkable on account of its position, facing as it does almost directly downward. It is oval in form, with the long axis directed antero-posteriorly, or approximately so, in Europeans. The size of the nostril is under the control of muscles (see p. 334) and may be dilated or constricted by their action.
below ferminate on each side in the margin of the nose [margo nasi]; posteriorly and interiorly the sides are expanded and more convex, forming the alae nasi. Each of these is separated from the rest of the lateral surface by a sulcus, and the inferior free margin of each bounds a naris laterally.
Three types of nose, distinguished by differences in the proportion of breadth and length are recognised by anthropologists: the leptorrhine or long, high nose; the platyrrhine or short, low nose; the mesorrhine, a form intermediate between the other two. The leptorrhine type prevails among white races, the platyrrhine in the blaeli peoples and the mesorrhine in the red and yellow races.
The framework of the external nose is formed partly of bone and partly of hyaline cartilage The bones, which form only the smaller superior part, are the two nasal bones and the fronta processes and anterior nasal spines of the two maxillae (pp. 87, 108).
The nasal cartilages [cartilagines nasi] are located about the piriform aperture and constitute the larger part of the nasal framework. There are five principal cartilages: superiorly, the two lateral nasal cartilages, interiorly the two greater
alar cartilages, and the single median nasal septal cartilage. Beides these there are the lesser alar cartilages, the sesamoid cartilages, and the vomero-nasal cartilages of Jacobson. The lateral nasal cartilages [cartilagines nasi laterales] are triangular and nearly flat lateral e.xpansions of the septal cartilage, placed one on each side of the nose just inferior to the nasal bone. Each presents an inner and an outer surface and three margins. The medial margin is continuous in its superior third with the anterior margin of the septal cartilage, and through this with its
fellow of the opposite side, but it is separated inferiorly from the septal cartilage by a narrow cleft. The curved supero-lateral margin is firmly attached b}^ strong fibrous tissue to the nasal bone and frontal process of the maxilla, and underlies these bones for a considerable distance, especially near the septum. The inferior margin is connected by fibrous tissue to the greater alar cartilage. The greater alar cartilages [cartilagines alares majores], variable in form, are situated one on each side of the apex of the nose (figs. 961, 963). Each is thin, pliant, curved, and so folded that it forms a medial and a lateral crus, which bound and tend to hold open each naris. The medial crus [crus mediale] is loosely attached to its fellow of the opposite side, the two being situated inferior to the septal cartilage and forming the tip of the nose and the inferior part of the mobile septum. The lateral crus [crus laterale] joins the medial crus at the apex of the nose; it is somewhat oval in shape, and curves dorsally in the superior and anterior portion of the ala. It is connected posteriorly to the nasal margin of the maxilla by a broad mass of dense fibrous and fatty tissue, and helps to maintain the contour of this part of the nose.
naris.
A variable number of small cartilages, lesser alar cartilages [cartilagines alares minores] are found in the fibrous tissue of the ala, and in the interval between each greater alar and lateral cartilage occur one or more small plates, sesamoid cartilages [cartilagines sesamoidese] (fig. 961).
The septal cartilage [cartilago septi nasi] (fig. 964) forms the anterior part of the septum. It is quadrilateral in shape and fits into the triangular interval of the bony septum. Its antero-superior margin in its upper part meets the internasal suture. Inferior to the nasal bone it presents a shallow groove which gradually narrows toward the tip of the nose, and whose borders are continuous superiorly with the lateral nasal cartilages, but are separated from their inferior twothirds by a narrow slit. The most inferior part of this margin of the septal cartilage is placed between the greater alar cartilages. The antero-inferior margin extends backward from the rounded anterior angle to the anterior nasal spine. Inferiorly it is attached to the medial crus of the greater alar cartilage and to the
THE NASAL CAVITY
mobile nasal septum. The postero-superior margin is attached to the perpendicular plate of the ethmoid, and the postero-inferior margin joins the vomer and the ventral part of the nasal crest of the maxilla, the cartilage broadening out to obtain a wide though lax attachment to the nasal spine.
The shape of the septal cartilage varies with the extent of the ossification of the bony septum. Even in the adult a strip of cartilage may extend for a varying distance posterosuperiorly between the vomer and perpendicular plate of the ethmoid, sometimes reaching the body of the sphenoid; it is known as the sphenoidal process of the septal cartilage [processus sphenoidalis septi cartilaginei]. The vomero-nasal cartilage [cartilago vomero-nasalis Jacobsoni*] is a narrow strip of cartilage firmly attached to each side of the septal cartilage, where this joins the anterior portion of the vomer.
soft palate
more adherent, and furnished with numerous exceptionally large sebaceous glands. At the nares it is reflected into the nasal cavity, where it passes into the mucous membrane. The hairs on the skin of the nose are very fine, except in the nares, where they may be strongly developed.
Vessels and nerves. — The arteries of the external nose are derived from the external maxillary (facial) artery (pp. 540 and 541), the ophthalmic artery (p. 554), and the infra-orbital artery (p. 549). The veins terminate in the anterior facial vein and the ophthalmic vein (p. 644). The lymphatics pass to the submaxillary lymphatic nodes (p. 712). The motor nerves are branches of the facial (p. 946). The sensory nerves are derived from the trigeminal through the frontal and naso-cihary branches of the ophthalmic (p. 936) and infra-orbital branch of the maxiUary (p. 939).
The nasal cavity [cavum nasi] is the ample space situated between the floor of the cranium and the roof of the mouth extending forward into the external nose and backward to the nasal part of the pharynx. With the exception of the inferior part of the nose its walls are of bone as already described (pp. 110, 112). The cartilages and membranes of the nose complete the boundaries anteriorly. Here the cavity opens to the exterior by the nares. At the back a free communi-
cation with the pharynx is established through the paired ehoana;. Furthermore accessory nasal cavities, the paranasal sinuses, open into the cavum nasi. The walls of the nasal cavity are covered with periosteum and mucosa, the latter presenting important differences in the respiratory and olfactory regions. The organ of smell, included in the nasal cavity, is described on p. 1049.
The cavum nasi is divided into right and left symmetrical parts, called the nasal fossae, by the septum of the nose [septum nasi]. The latter is supported by a framework composed of the osseous septum [septum nasi osseum] posteriorly, and the cartilaginous septum [septum cartilagineum] anteriorly. Antero-inferiorly, the small movable part of the septum is also called the membranous septum [septum membranaceum].
Fig. 966. — Sagittal Section through the Facial Part op the Head and the Bodies OP THE UPPER THREE Cervical Vertebrae. The section lies to the right of the median plane. The nasal septum has been removed. (Rauber-Kopsch.)
In the septum, upon each side, just superior to the nasal spines of the maxillas, there is frequently a minute opening leading superiorly and posteriorly and ending blindly. This cavity is closely related to the vomero-nasal cartilage and is a rudimentary representative of the vomeronasal organ (of Jacobson) [organon vomero-nasale], which in some animals is well developed and receives a branch of the olfactory nerve. On the floor of the nasal cavity about 2 cm. from the posterior margin of the naris and near the nasal septum a small depression, the nasopalatine recess, is often seen. This is the mouth of the incisive duct [ductus incisivus] which leads into the incisive canal for a greater or less distance and may even extend to the mouth, where its termination is marked by the incisive papilla. The incisive duct indicates the position of a foramen which in the embryo connected the mouth and nose.
The naris leads upward into the vestibule of the nose [vestibulum nasi], the small cavity within the compass of the greater alar cartilage. Its walls are lined with skin beset with the large hairs called vibrissas and containing many sebaceous glands. The vibrissae serve to protect the nasal cavity from the entrance of foreign matter. On the lateral wall, the vestibule is marked off from the rest of the nasal cavity by a cUstinct ridge, the limen nasi, corresponding to the superior margin of the greater alar cartilage. On the lateral wall of the cavity within the limen nasi are three antero-posterior ridges, the superior, middle, and inferior
conchae (fig. 966). These have a bony framework (described on pp. 83, 110) and are covered by the mucous membrane of the nose. The conchje are not parallel to one another but converge in a backward direction. The superior nasal concha [concha nasaUs superior] is the smallest, projects only slightly medialward and downward from the upper, posterior part of the lateral wall, overhanging the groove called superior meatus of the nose. The middle nasal concha [concha nasalis media] is extensive, reaching from the fore part to the posterior confines of the lateral wall. Its free margin is nearly vertical in its anterior one-fourth, horizontal and laterally rolled in the rest of its extent. Under cover of this concha runs the middle meatus. The inferior nasal concha, [concha nasalis inferior] is the longest, has a lateral attached and an inferior laterally rolled free margin running near the floor of the nasal cavity. Beneath it lies the inferior meatus.
ity which lies between the septum nasi and the nasal conchas and stretches from floor to roof. The three meatuses under cover of the nasal conchae have been mentioned. These passages all communicate freely with the common meatus, extend antero- posteriorly and have a greater capacity in front than behind. The superior meatus [meatus nasi superior] is the smallest of the three. Into it open the posterior ethmoidal cells by one or two small foramina. The sphenopalatine foramen, which communicates with the meatus in the dry skull, is entirely covered up bj^ mucous membrane. The middle meatus [meatus nasi medius] is a much larger passage. Upon its lateral wall is a rounded eminence, the ethmoidal bulla, caused by the middle ethmoidal cells and perforated by the opening into them. Inferior to this is a deep curved groove, the hiatus semilunaris, which is continued superiorly by the ethmoidal infundibulum [infundibulum ethmoidale] into the frontal sinus. It also receives the openings of the anterior ethmoidal cells and the maxillary sinus. The inferior meatus [meatus nasi inferior] is the longest of the three. Upon its lateral wall, just inferior to the attachment of the inferior concha, is the slit-like opening of the naso-lacrimal duct [ductus naso-lacrimalis], around the opening of which the mucous membrane forms a valve, the plica lacrimalis (Hasneri).
1206 THE RESPIRATORY SYSTEM
The attached margins of the middle and inferior conchse are both arched, the convexities being upward. The highest point of the convexity is near the middle of the attached margin in the inferior concha and lies about 17 mm. above the floor of the nose; the anterior end of this concha is approximately 25-35 mm. distant from the apex of the nose (KaUius).
From the anterior end of the middle concha a slight variable elevation of the mucous membrane of the nose extends forward and downward. This, the agger nasi, which is regarded as of constant occurrence in the new-born, appears to be a rudimentary representative of the nasoturbinale of mammals (Schwalbe).
Below the agger nasi a broad depression of the lateral wall, the atrium meatus medii, leads posteriorly beneath the anterior free margin of the middle concha to the middle meatus, while above the agger, between it and the roof of the nasal cavity, the slight olfactory groove [sulcus olfactorius] ascends upon the lateral wall to the olfactory region. In this region, above the superior concha, is a corner of the nasal cavity of interest on account of the sphenoidal sinus opening into it: this is the spheno-ethmoidal recess [recessus spheno-ethmoidalis].
Variation in the number and position of the openings into the meatuses is of practical interest. An accessory mouth of the maxillary sinus is rather frequently met with, especially in old people; it lies most commonly behind the hiatus semilunaris. The infundibulum ethmoidale may open independently of the hiatus semilunaris at a spot beneath the anterior end of the attached margin of the middle concha. In the inferior meatus the mouth of the naso-laorimal duct, which is found 22-25 mm. behind the posterior margin of the nares, may have one or more accessory openings associated with it; these are perforations of the plica lacrimalis.
Communication between the nasal cavity and the nasal part of the pharynx is effected by means of the paired posterior apertures [choanse]. These are oval in form, their height greater than their width. They are located at either side of the posterior edge of the nasal septum and are limited above by the body of the sphenoid, below by the line of junction of the hard and soft palate.
From the plane of the choana forward a rather constricted portion of the nasal cavity extends for a short distance to reach the level of the posterior ends of the middle and inferior conchse. Into this region, which is known as the meatus naso-pharyngeus, open posteriorly the superior, middle and inferior meatuses. Posterior rhinoscopic examination reveals the choanse, the naso-pharyngeal meatus, the posterior extremities of the three conchse and of the meatuses beneath them.
Dimensions of the nasal cavity. — The length of the floor averages approximately 40 mm., the width 32 mm., the height from floor to lamina cribrosa 47 mm. The length of the lateral wall is about 63 mm. The choana measures 29.8 mm. high and 15.5 mm. broad. The area of the two nares is 2 sq. cm.
Paranasal sinuses [sinus paranasales] (figs. 964-968). — The location, form and relations of the bony-walled spaces connected with the nasal cavity have been fully described in the section on Osteology. The conditions observed in the living subject differ in certain respects from those present in the macerated skull; the spaces are lined by a mucous membrane which, though affecting but slightly the form of these chambers, modifies considerably the openings by which they communicate with the nasal cavity. These openings permit the entrance and exit of air and to some extent the escape of fluids which may accumulate in the sinuses. While the significance of these spaces is not at present clear it is, however, certain that they function in lightening the weight of the skull, and probable that indirectly they serve in connection with the sense of smell.
Entrance into the maxillary sinus is offered through the middle part of the hiatus semilunaris, that is, the deep, narrow notch between the ethmoidal bulla and uncinate process of the ethmoid. Viewed from within the sinus, the opening appears as an oval window in the upper part of the medial wall — a position unfavourable to the discharge of matter, when the body is in the upright posture. An accessory opening, situated behind the normal ostium, is present in about 10 per cent, of cases.
Mediolateral 23 mm.
Increase in capacity of the maxillary sinus is sometimes observed as the result of more or less extensive excavation of the bony processes of the maxilla adjacent to it, viz. : the alveolar, palatal, frontal and zygomatic. On the other hand narrowing of the cavity is encountered,
caused by unusually thick walls of bone, bulging inward of the facial or nasal walls, and through retention of teeth. Incomplete division into two parts through the presence of a septum has several times been observed. Communication with ethmoidal cells and with the cavity of the orbital process of the palate bone sometimes exists.
Frontal sinus [sinus frontalis] (figs. 78, 964, 968). — The paired frontal sinuses, separated from each other by a bony septum, have in general the shape of a threesided pyramid with the base below and the apex formed above in the frontal squama. In the base near the septum is located the superior aperture of the infundibulum which, it will be recalled, opens inferiorly at the anterior extremity of the hiatus semilunaris.
The form and size of the frontal sinuses are exceedingly variable. They may extend backward in the orbital part of the frontal bone as far as the suture between it and the small wing of the sphenoid; laterally into the zygomatic process; upward toward the coronal suture. The capacity of the sinus, as determined in a small number of cases, varied from 3 to 7.8 ccm. (Brvihl). Asymmetry of the septum is frequently observed. Absence of one of the sinuses is not a rare condition; absence of both is occasionally encountered.
Ethmoidal cells [cellulse ethmoidales] (figs- 965, 968). — The openings of the anterior cells into the semilunar hiatus and infundibulum, and of the posterior cells at the superior meatus have already been described.
Communications between the ethmoidal cells and the sphenoidal and maxillary sinuses are not rare; the cavity in the orbital process of the palate bone may open into the posterior cells. In old age, foramina through the lamina papyracea may appear, leading to the introduction of air into the orbit.
Sphenoidal sinus [sinus sphenoidalis] (figs. 964, 965, 966). — The apertures of the paired sphenoidal sinuses are, on account of the mucous membrane covering, much smaller than they are in the dried skull. They lie in the anterior wall near the septum, nearer the roof than the floor, and open into the spheno-ethmoidal recess.
Extension of the sphenoidal sinuses backward and also into neighbouring processes, and communication with ethmoidal cells and with the small cavity of the orbital process of the palate are not unusual. The capacity of the sinus varies between 1 and 4.2 ccm. (Briihl).
Functions of the paranasal sinuses. — Various functions have been attributed to the sinuses near the nose, none of which is entirely satisfying. Medieval anatomists proposed that these cavities contributed to the resonance of the voice, or that they supplied the mucus by which the nasal cavity is kept moist. Lightening the skull, warming the inspired air and taking part, indirectly, in the sense of smell are functions assigned by anatomists of later times.
The mucous membrane of the nose [membrana mucosa nasi]. — The nasal cavity is completely lined with mucous membrane, which inferiorly, at the limen nasi blends with the skin covering the walls of the vestibule (p. 1204). Posteriorly it joins the mucous membrane of the pharynx and palate. It covers some of the
openings which are seen in the bony walls; those apertures, however, which lead into the paranasal-sinuses and into the naso-lacrimal duct remain patent, although as already stated the bony openings are much reduced in size.
In the nasal cavity the bright rose-red vascular mucous membrane is tightly bound to the periosteum and perichondrium, and is covered with a cihated columnar epithelium. A very considerable venous plexus is found in many parts of the nasal mucosa. Over the inferior concha and to a less extent in the mucosa of the middle and superior conchEB, it forms the cavernous plexuses of the conchse [plexus cavernosi concharum] contributing to build up about these bodies a true erectile tissue. The thickness which these glands and venous plexuses give to the mucous membrane of the conchoe causes the marked increase in size of these bodies over that of their bony supports. The region covered by the mucous membrane just described forms the greater part of the nasal cavity, and is loiowTi as the respiratory region [regio respiratoria]. The mucous membrane of a small area over the superior concha and the adjacent septal wall (fig. 969) has a somewhat different structure. In this area the olfactory nerves are distributed, whence it is known as the olfactory region [regiojolfactoria] and its mucous membrane, compared with that of the respiratory region, is less vascular, yellow or yellowishbrown in colour, and covered by a non-ciliated epitheUum. Its cells, specially modified, some of which are directly connected with the olfactory nerve, form the olfactory organ [organon olfactus]. Small mucous olfactory glands [glanduloe olfactoria;] occur in the region. The mucous membrane which lines the paranasal sinuses throughout is a continuation of the nasal mucosa; it is, however, paler, less vascular, somewhat thinner, and more loosely attached to the bones. Mucous glands are numerous.
ethmoid ant pal
Vessels and nerves. — The arteries of the nasal cavity are the spheno-palatine artery from the internal maxillary which, through its posterior lateral nasal branches, supplies the middle and inferior conchfe (p. 549), the anterior and posterior ethmoidal arteries from the ophthalmic (p. 553), the descending palatine artery from the internal maxiUary (p. 549), and the superior labial branch of the external ma.xiUary to the vestibule. The venous plexuses of the mucous membrane are drained posteriorly by the spheno-palatine to join the pterygoid plexus, superiorlj by the anterior and posterior ethmoidal veins to join the superior ophthalmic vein, and anteriorly by small branches to join the facial. The lymphatics form a weU-developed plexus which is said to communicate indirectly, through the lymphatics surrounding the olfactory nerves, with the subdural and subarachnoid spaces. Posteriorly two or more well-developed trunks communicate with the pharyngeal lymphatics, and anteriorly the nasal lymphatics join with the lymphatics of the face. The olfactory nerves pass through the cribriform plate of the ethmoid bone and are distributed to the olfactory area (p. 929). The trigeminal nerve furnishes the following branches to the nasal cavity: — branches from the naso-ciliary branch of the ophthalmic nerve ; the Vidian nerve ; the posterior superior and posterior inferior nasal and the anterior palatine from the spheno-palatine ganglion (p. 962); the anterior superior alveolar from the infra-orbital division of the maxillary nerve (p. 938).
The development of the nose. — The nasal cavity malves its appearance as a depression of the ectoderm on either side of the median line, immediately in front of the oral fossa, with which the depressions are at first continuous. Later, by the union of the maxillary and globular processes (see p. 18), the depressions are separated from the anterior part of the oral fossa, and this separation is continued by the formation of the palatal processes of the maxillas and palatine bones, so that finally the nasal cavities communicate posteriorly only with the pharynx.
The cartilage which forms the lateral walls of the nasal fossas is at first quite smooth, but later it becomes eroded by absorption, whereby the nasal concha; are formed. The erosion also extends into the ethmoid bone, forming the ethmoidal cells, and into the neighbouring bones to form the frontal, sphenoidal, and maxillarjf sinuses.
The larynx (figs. 960, 970, 971,), is a tubular organ, the framework of which is made of cartilages joined together and of elastic membranes. Its inner surface is covered by mucosa. From the membranes are formed a pair of vocal folds which, by the passage of air through the larynx, are thrown into vibration and so function in the generation of sound. These folds are affected in respect to their
tension and in their mutual relation by the actions of a system of laryngeal muscles under the control of the vagus nerve and are made thereby, on the one hand, to produce those modifications of the sound involved in the voice and on the other hand to regulate the amount of air passing through the cavity of the larynx. The latter communicates above with the pharynx by means of the opening called the laryngeal aperture, and below with the cavity of the trachea. Figure 970 shows the laiyngeal aperture with its boundaries, the epiglottis and
The cricoid cartilage [cartilago cricoidea] (figs. 973, 974, 975, 978), single, has been compared in its shape to a signet ring. Its position is at the lower end of the larynx, where it is connected with the first ring of the trachea. Posteriorly the cricoid cartilage expands into a broad lamina [lamina cartilaginis cricoidese] which enters into the posterior boundary of the laryngeal cavity, while laterally and in front it forms a narrow arch [arcus cartilaginis cricoideae]. On either side of the upper margin of the lamina is the elliptical arytaenoid articular surface [facies articularis arytsenoidea] its long axis parallel with the margin of the cricoid, its steeply sloping surface convex for articulation with the arytsenoid cartilage. The hinder surface of the lamina presents a median ridge and lateral impressions for the attachment of the posterior crico-arytsenoid muscles. The arch, weakest
in its middle part, presents concave upper and straight lower margins. A circular, elevated thyreoid articular surface [facies articularis thyreoidea] for articulation with the inferior cornu of the thyreoid cartilage is situated upon the side of the cricoid where arch and lamina are continuous. The internal surface is covered by the laryngeal mucosa.
The thyreoid cartilage [cartilago thyreoidea] (figs. 973, 974, 975, 977), single and the largest in the laryngeal skeleton is composed of two broad laminae, right and left, which meet and are fused anteriorly in the mid-line in a right angle, partly covering the other cartilages laterally and in front. The laminae are stout, but their connection at the angle is through a weak strip of cartilage. The upper margin of each lamina is convex, and in front drops abruptly to form in the median line the superior thyreoid notch [incisura thyreoidea superior] . The anterior edges
CARTILAGES OF THE LARYNX
meeting in the angle produce the laryngeal prominence [prominentia laryngea] ("Adam's apple"), which is seen on the front of the neck. The horizontal inferior margin presents near its middle the inferior thyreoid tubercle [tuberculum thyreoideum inferius], and in the median line the inferior thyreoid notch [incisura thyreoidea inferior]. The thick posterior margin of each lamina is continued above the superior edge in the long superior cornu [cornu superius], and below the inferior margin in the short inferior cornu [cornu inferius]. The former is directed slightly backward and medial ward, and joins with the end of the greater cornu of the hyoid by ligament. The inferior cornu, curving medialward as it descends, articulates by a flat, circular facet upon the medial side of its extremity with the thyreoid articular surface of the cricoid cartilage. The external surface of the lamina affords attachment for muscles and presents in its upper posterior part the
A thyreoid foramen [foramen thyreoideum], sometimes seen in the upper part of the lamina, giving passage to the superior laryngeal artery, results from the incomplete union of the fourth and fifth branchial cartilages from which the lamina are derived. The oblique line [lines obUqua], extending between the thyreoid tubercles, is commonly present and is regarded by many anatomists as a normal feature of the external surface of the thyreoid cartilage. It marks the attachment of the sternohyoid and thyreohyoid muscles. At the insertion of the vocal ligaments in the angle of the laminae a small perichondral process is often observed.
The arytaenoid cartilages [cartilagines arytsenoidese] (figs. 973, 977, 978, 979), paired, surmount the lamina of the cricoid cartilage and give attachment to the vocal ligaments, whose relations and state of tension are altered by the changes in position which these cartilages are almost constantly undergoing.
Each cartilage is pyramidal in form, and moulded for the attachment of several muscles. The apex, which is above, is bent backward and medialward and is connected with a corniculate cartilage. The base, somewhat triangular in shape, presents at the lateral and posterior part an oval or circular concave articular surface [facies articularis], directed medialward and downward to meet the aryteenoid articular surface of the cricoid cartilage. The lateral angle of the base is prolonged into a stout muscular process [processus muscularis] for the attach-
ment of the crico-arytsenoid muscles, while the anterior angle is extended as a sharp projection, the vocal process [processus vocalis], which serves for the attachment of the vocal ligament. The surfaces of the arytsenoid are named medial, posterior, and antero-lateral. The narrow medial surface, covered by the mucosa of the larynx, is nearly vertical, and faces the corresponchng side of the opposite arytsenoid, from which it is separated by a small space. The posterior surface is concave for muscular attachment. The antero-lateral surface is the largest, and presents an irregular contour.
On this surface a ridge, the arcuate crest [crista arcuata], extends horizontally between two hollows — the triangular fovea [fovea triangularis] above, which lodges some mucous glands, and a larger depression below, the oblong fovea [fovea oblonga] for the vocal muscle. The colliculus is a small eminence found upon the anterior margin and antero-lateral surf ace.
Tracheal cartilagt
The corniculate cartilages (of Santorini) [cartilagines corniculatse (Santorini*)] (figs. 973, 977). — This pair of small conical cartilages is set upon the bent apices of the arytsenoids, continuing their curves backward and mechalward.
The corniculate cartilage is not an independent structure in many lower animals, and its continuity with the arytsenoid is sometimes met with in man where the two cartilages are normally developed in a continuous mass of tissue.
The epiglottic cartilage [cartilago epiglottica] (figs. 973, 977, 981, 987), unpaired, invested by mucosa behind and partly in front, thin and leaf-shaped, stands behind the root of the tongue and the body of the hyoid. It lies above the thyreoid cartilage, in front of the entrance of the larynx. The free upper margin is convex, or notched; the lower end tapers to a short stalk, the petiole of the epiglottis [petiolus epiglottidis], to which the thyreo-epiglottic ligament is attached.
the hyo-thyreoicl ligament. Its posterior surface above is saddle-shaped; below, it is convex, presenting the epiglottic tubercle [tuberculum epiglotticum]. To the margins are attached the ary-epiglottic folds. The epiglottic cartilage presents numerous small holes and depressions for the accommodation of glands. The cuneiform cartilages (of Wrisberg) [cartilagines cuneiformes (Wrisbergi*)] (fig. 973) lie as small, rod-like bodies in the ary-epiglottic folds anterior to the corniculate_ cartilages. They are variable in form and size and not rarely absent altogether.
These cartilages are parts of the epiglottic cartilage in some mammals where, as in man, they he in the ary-epiglottic folds. Their relations to the arytEcnoids are regarded as secondary. Sutton has shown that in the ant-eater a continuous rim of yellow elastic cartilage extends from the sides of the epiglottic cartilage to the summits of the aryttenoids. A minute unpaired inlerarylmnoid or procricoid cartilage is rarely present imbedded in the cricopharyngeal ligament and covered by the pharyngeal mucosa. It is a constant structure in certain mammals. A pair of small sesamoid cariilages, also constantly present in some mammals, is occasionally found in man at the lateral margins of the arytaenoids, connected with them and with the corniculate cartilages by elastic ligaments.
Structure of the cartilages. — The thyreoid, cricoid, and greater part of the aryta;noid are composed of hyaline cartilage; the epiglottic, corniculate, and cuneiform cartilages, as well as the ape.x and vocal process of the arytsenoid, are of elastic cartilage. Certain parts of the laryngeal skeleton normally undergo calcification and subsequent ossification. Calcification begins at about twenty years of age in the thyreoid and cricoid cartilages, and later in the arytenoid. The process begins a little later in the female than in the male, and does not extend so rapidly. The extent to which the cartilages are ossified and the time occupied in the process vary considerably. The elastic elements are not involved in the process.
The crico-thyreoid articulation (figs. 973, 974, 975). — The articular surfaces concerned are the thyreoid articular surface on the side of the cricoid and the articular surface on the inferior cornu of the thyreoid cartilage. The cricothyreoid articular capsule [capsula articularis cricothyreoidea] attached around the margins of these surfaces and certain accessory bands serve to bind the cartilages together.
The accessory bands, cerato-cricoid ligaments fall into three groups radiating from the inferior cornu: the ligamenta ceratocricoidea posteriora upward and medialward to the superior margin of the cricoid; tlie ligamenta ceratocricoidea lateralia downward at the side and back of the capsule; the ligarnentum ceratocricoideum anterius downward and forward. The capsule possesses a synovial layer.
The crico-arytaenoid articulation [articulatio cricoarytsenoidea (figs. 973, 977, 978). — The articular surface of the cricoid cartilage and the articular surface of the arytsenoid which enter into this articulation are so disposed that at no time do they meet in complete apposition. A loose capsule [capsula articularis crico-
MEMBRANES OF THE LARYNX 1215
of the cricoid, is important in helping to fix the former cartilage in place upon the sloping arytaenoid articular surface of the cricoid and in limiting its movements. Motion at this articulation is very free. The following simple movements of the arytaenoid are best understood:— (1) gliding of the arytaenoid toward or away from its fellow; (2) inclining forward and backward; (3) rotating on a vertical axis, so that the vocal process sweeps medialward or lateralward and also a little downward or upward.
The petiole of the epiglottic cartilage is connected with the thyreoid, below and behind the superior notch, by a strong, elastic thyreo-epiglottic ligament [lig. thyreoepiglotticum] (fig. 977).
This name is given to a more or less continuous sheet of elastic fibres connected with the deeper parts of the laryngeal mucosa. Its upper part is known as the quadrangular membrane, the lower part as the elastic cone. A middle region of the elastic membrane lies opposite the ventricle of the larynx.
The quadrangular membrane (figs. 978, 981, 988) extends from the ary-epiglottic folds above to the level of the ventricular folds (false vocal cords) below. The lateral parts of this membrane are widely separated superiorly, but they converge toward the middle line as they descend. Anteriorly, the membrane is fixed in the angle of the thyreoid laminae and to the sides of the epiglottic cartilage; posteriorly, to the corniculate cartilages and to the arytaenoids. The superior edge on either side lies within the ary-epiglottic fold, which it supports; it slopes downward and backward and includes the cuneiform cartilage. The inferior edge, horizontal and in a sagittal plane, is best developed in front, where it is attached in the angle of the thyreoid a little way from the middle line ; behind, it is fixed to the medial margin of the triangular fovea of the arytsenoid. This inferior free margin, differentiated as the ventricular ligament [lig. ventriculare], is enclosed within, and is the support for the ventricular fold.
The elastic cone [conus elasticus] (figs. 978, 979). — -This part of the elastic membrane extends from the level of the vocal folds to the superior margin of the cricoid cartilage. Its component fibres are attached in the re-entrant angle and adjacent lower margin of the thyreoid cartilage, whence they spread downward and backward to the upper edge of the cricoid arch and to the arytsenoid cartilages. The strong anterior portion, perforated by vessels, is the median cricothyreoid ligament [fig. cricothyreoideum (medium)] (figs. 974, 975). The lateral parts (lateral portions of the crico-thyreoid membrane) present superior free edges, somewhat thickened, which, running horizontally near the middle line from the thyreoid angle to the vocal processes, constitute the vocal ligaments. These are inserted anteriorly into a perichondral process in the thyreoid angle; posteriorly, they have a wide area of attachment to the upper and medial surfaces of the vocal processes of the arytaenoids with the elastic fibres of which they are in part continuous. A yellowish, cellular nodule (sometimes cartilage) occurs in the
The median crico-thyreoid ligament is incised m the operation of laryngotomy. It is crossed by the anastomotic arch of the crico-thyreoid arteries, which, however, can be avoided in the operation by making a transverse cut through the ligament close to the superior margm of the arch of the cricoid cartilage.
The hyo-thyreoid membrane [membrana hyothyreoidea] (figs. 977, 980, 981) is a loose, fibrous, elastic sheet, binding together the thyreoid cartilage and hyoid bone. It extends from the superior margin of the former to the greater cornua and
superior margin of the body of the latter. The superior laryngeal artery and vein and the internal laryngeal nerve pass through it from the side. Its posterior and lateral edge is cord-like, consisting of elastic fibres which stretch as the lateral
hyo-thyreoid ligament [lig. hyothyreoideum laterale] from the superior cornu of the thyreoid to the greater cornu of the hyoid. A small cartilago triticea is sometimes present in this band. The middle part, median hyo-thyreoid ligament [hg.
hyothyreoideum medium] thick and elastic, extends from the superior thyreoid notch upward behind the body of the hyoid to be attached to its superior margin, the hyoid bursa being interposed between the bone and the membrane.
in the embryo. It persists in adult hfe in some lower animals.
The hyo-epiglottic ligament [lig. hyoepiglotticum] (figs. 978, 981) connects the anterior surface of the epiglottic cartilage with the superior margin of the body and the greater cornua of the hyoid. It is a broad sheet, lying above a mass of fat which stands between the median hyo-thyreoid membrane and the epiglottis and spreading laterally to join the pharyngeal aponeurosis in the region of the piriform recess.
glottic fold.
The corniculo -pharyngeal ligament (fig. 977) extends from the corniculate cartilage downward and toward the median hne, attaching to the mucosa of the pharjoix and joining its fellow behind the arytaenoid muscle. From this point a single band, the crico -pharyngeal ligament [hg. oricopharyngeum], which may enclose a nodule of cartilage (the interarytsenoid or procricoid cartilage), descends in the middle line, to be fixed to the cricoid lamina and into the pharyngeal mucosa.
The larynx and trachea are united by fibrous membrane, the crico-tracheal ligament [lig. cricotracheale] (figs. 974, 978), between the inferior margin of the cricoid cartilage and the upper margin of the first tracheal ring. Posteriorly the ligament is continued into the membranous wall of the trachea.
Of the many muscles connected with the larynx, two groups may be recognised, the members of one coming from neighbouring parts, fixing themselves to the larynx and acting upon the organ as a whole; the members of the other group confining themselves exclusively to the larynx and acting so as to affect its parts. The muscles composing the first group are described elsewhere. (See Section IV.) The muscles of the second group are composed of striated fibres and are supplied by the vagus nerve through its laryngeal branches. These muscles are all more or less under cover of the thyreoid cartilage, with one exception, the crico-thyreoid.
The crico-thyreoid muscles [m. cricothyreoideus] (fig. 980) are placed one on either side of the outer surface of the larynx in its lower part. Each muscle is partially separated into an anterior straight [pars recta] and a posterior oblique portion [pars obliqua], which together arise from the arch of the cricoid. The fibres of the straight part ascend steeply and are inserted into the inferior margin of the thyreoid cartilage. The oblique portion is inserted into the inferior cornu and into the lower margin and inner surface of the thyreoid cartilage.
The straight part elevates the arch of the cricoid, causing the lamina, and with it the arytsenoid cartilages, to sLuk, while the obhque part draws forward the thyreoid; thus the vocal ligaments are made tense. The muscle is supplied by the external branch of the superior larjTigeal nerve. A connexion between the posterior part of this muscle and the inferior constrictor of the pharynx and their common nerve-supply indicate their genetic relationship.
The posterior crico-arytffinoid muscle [m. cricoarytasnoideus posterior] (figs. 980, 981, 982), paired, is situated at the back of the larynx, covered by the submucous coat of the pharynx. It is a thick, triangular mass which takes origin from the posterior surface of the cricoid lamina, the two muscles being well separated by the median crest of the cartilage. The lower fibres ascend and the upper ones pass horizontally lateralward and are inserted into the muscular process of the arytaenoid cartilage on its posterior surface and tip.
When these muscles contract, the muscular processes of the arytsenqids are puUed backward and downward, while the vocal processes travel lateralward and a Uttle upward, so that the rima glottidis is widened and the vocal hgaments made tense (fig. 982). The innervation is by the posterior branch of the inferior laryngeal nerve.
strictors. They form a ring, the constrictor laryrigis, around the laryngeal cavity, interrupted, however, by the cartilages. In the larynx of amphibia and reptiles a complete sphincter guards the entrance to the air-passages.
The following muscles are included in the constrictor group: — The transverse arytaenoid muscle [m. arytaenoideus transversus] (figs. 981) 983, 985) is. a single muscle of quadrilateral form, extending across the middle line from the posterior concave surface of one arytaenoid cartilage to that of the other. Its anterior surface, between the cartilages, is covered by the laryngeal mucosa; its posterior surface, crossed by the arytaenoideus obliquus, is clothed by the submucous coat of the pharynx.
The arytaenoideus transversus approximates the arytenoid cartilages and their vocal processes, which are at the same time elevated, and the vocal Ugaments made tense. It is supplied by the posterior branch of the inferior laryngeal nerve.
Inferior laryngeal
The lateral crico -arytaenoid muscle [m. cricoarytaenoideus lateralis] (fig. 981) arises from the upper margin and outer surface of the cricoid arch and from the elastic cone, whence the fibres extend backward and upward to an insertion on the anterior surface of the muscular process of the arytaenoid cartilage. This muscle is inseparable from the thyreo-arytsenoideus in about half the cases.
The lateral oricoarytsnoids by their contraction cause the vocal processes to move toward the median line and a little downward, so that the vocal Ugaments are approximated and shghtly stretched. They antagonise the posterior crico-arytaenoids. The anterior branch of the inferior laryngeal nerve supphes these muscles.
The external thyreo-arytaenoid muscle [m. thyreoarytsenoideus (externus)] (figs. 981, 984, 988), variable in form and in the disposition of its fibres, is closely connected with the preceding. It Hes under cover of the thyreoid lamina lateral to the laryngeal saccule (ventricular appendix) and elastic cone. Arising within the angle of the thyreoid laminae the muscle extends upward and backward to its insertion on the lateral margin of the arytaenoid cartilage.
It draws forward the arytsenoid cartilage (and also tilts the cricoid), and rotates it so that the vocal process passes medialward and downward, relaxing the vocal ligament. It is the antagonist of the crioo-thyreoid (fig. 984). Its nerve-supply is the anterior branch of the inferior laryngeal.
The vocal muscle [m. vocalis], (fig. 988), prismatic in form, is tiie inner constant part of tlie thyreo-arytasnoideus. It lies in tiie vocal lip lateral to the vocal ligament. Its fibres run from their origin in the angle of the thyreoid laminse to their insertion in the vocal process and oblong fovea of the arytaenoid cartilage.
anterior branch of the inferior laryngeal.
The insertion of certain fibres of this muscle into the elastic vocal ligament has been observed (ary-vocalis muscle of Ludwig). D. Lewis has shown that some of the elastic fibres in the vocal ligament are derived from the perimysium of the vocal muscle.
The ventricular muscle [m. ventricularis] consists of a few fibres derived from the thyreoarytffinoideus which reach the back of the laryngeal saccule and enter the ventricular fold. The small thyreo-arytwnoideus superior extends from the angle of the thjrreoid to the muscular process of the arytaenoid upon the lateral surface of the main muscle.
The oblique arytsenoid muscle [m. arytsenoideus obhquus] is a slender band lying at the back of the larynx and under the pharyngeal submucosa. It arises from the muscular process of the arytsenoid posteriorly, and, ascending obliquely, crosses its fellow in the median line. Some fibres are inserted into the apex of the opposite arytsenoid cartilage; other fibres sweep around the apex and accompany the thyreo-arytsenoid to an insertion in the angle of the thyreoid cartilage, constituting the thyreo-arytcenoideus obliquus.
Closely connected with the thyreo-arytsenoideus is a bundle of fibres of fairly regular occurrence, called the thyreo-epiglottic muscle [m. thyreoepiglotticus] (fig. 981). It originates from the inner surface of the thyreoid lamina and proceeds upward and backward to end in the quadrangular membrane and to become attached to the lateral border of the epiglottis.
The ary-membranosus and ary-epiglotlic muscles are inconstant fascicles of the constrictor group which run in the ary-epiglottic fold and become fixed into the quadrangular membrane and margin of the epiglottic cartilage.
Summary of the Actions of the Laryngeal Muscles
According to their actions, the laryngeal muscles may be divided into — (a) those which effect the tension of the vocal folds; (b) those which control the rima glottidis; (c) those which effect the closure of the laryngeal aperture and vestibule.
(a) The vocal ligaments are made tense by the action of the crico-thyreoid, the lateral and posterior cricoarytsenoid and the transverse arytaenoid muscles. The vocal ligaments are relaxed as the result of the action of the external thyreo-arytaenoid and vocal muscles.
(6) The rima glottidis is widened by the crico-arytajnoideus posterior and made narrow by the contraction of the arytaenoids. The crico-arytaenoideus lateralis also assists in closing the rima glottidis by rotating the vocal processes medialward, and if the crico-arytsenoideus posterior contracts simultaneously, it aids in the closure. The vocal hgaments are approximated also by the thyreo-arytaenoideus [externus].
(c) The laryngeal aperture and vestibule are closed mainly by the arytsenoideus transversus and thyreo-arytsenoideus (externus), by which the arytaenoid cartilages are brought into apposition and drawn toward the epiglottis. Other muscles derived from the constrictor group, arytaenoideus obliquus and ary-epiglotticus assist in closing the laryngeal aperture.
CAVITY OF THE LARYNX AND LARYNGEAL MUCOSA
The cavity of the larynx [cavum laryngis] is relatively narrow and does not correspond in shape with the outer surface of the organ. Its form is shown in fig. 986 taken from a cast of the laryngeal cavity and the spaces continuous with it. Its walls are covered throughout by the mucous membrane of the larynx (figs. 987, 988).
The mucosa of the larynx is continuous above with the mucous membrane of the pharynx, below with that of the trachea (figs. 970, 971). At the root of the tongue the pharyngeal mucosa is reflected backward to the anterior surface of the epiglottis, presenting the median and lateral glosso-epiglottic folds [plica
glosso epiglottica medianaet lateralis]. From the sides of the pharynx it passes medialward, first sinking between the thyreoid cartilage laterally and the arytsenoid and cricoid medially, entering into the walls of the piriform recess; then passing over the superior margin of the quadrangular membrane to form the aryepiglottic fold.
At the medial side of the piriform recess a slight fold of the mucosa [phca nervi laryngei) corresponds to the superior lar3Tigeal nerve. Between the root of the tongue and the epiglottis is a depression subdivided in the middle line and limited laterally by the median and lateral
glosso-epiglottic folds; this is the epiglottic vallecula [vallecula epiglottica]. The piriform recess and the epiglottic vallecula are favorite sites for the lodgment of foreign bodies. The ary-epiglottic fold [plica aryepiglottica] extends from the side of the epiglottis to the apex of the aryt:rnoid cartilage; within it are fibres of the ary-epiglottic and thyreo-epiglottic muscles and the cuneiform and corniculate cartilages. These cartilages correspond to two rounded eminences on each side of the laryngeal entrance, the cuneiform and corniculate tubercles [tuberculum cuneiforme (Wrisbergi); tubereulum corniculatum (Santorini)], respectively. Of these, the former is often small and inconspicuous, the latter usually well developed and prominent.
The cavity of the larynx above the level of the ventricular folds is known as the vestibule [vestibulum laryngis]. This is wide in its upper part, but the sides incline toward the median line in descending, and the cavity becomes narrow
transversely in approaching the region of the glottis. Here the cavity has received the special name, superior entrance to the glottis [aditus glottidis superior]. The parts of the framework of the larynx which enter into the walls of the vestibule are : in front, the epiglottic and thyreoid cartilages with the thyreo-epiglottic hgament; at the side, the quadrangular membrane, the cuneifoi-m and corniculate cartilages, and the medial surface of the arytsenoid cartilage; behind, the anterior surface of the transverse arytsenoid muscle. The vestibule communicates with the pharynx by the laryngeal aperture [aditus laryngis] (figs. 970, 971, 972, 987), which looks upward and backward. The form of the aperture is oval or triangular, with the base in front; here it is bounded by the epiglottis; laterally by the aryepiglottic fold of the mucosa. Posteriorly the laryngeal aperture is prolonged as a little notch between the corniculate cartilages and the apices of the arytsenoids [incisura interarytsenoidea] limited behind by a commissure of the mucosa.
higher in front than behind, show two slight ridges, separated by a shallow groove, extending downward from the cuneiform and corniculate tubercles. The posterior wall, very low, corresponds to the commissure connecting the arytsenoid cartilages.
On either side of the vestibule, toward its inferior end, is the sagittally running ventricular fold [plica ventricularis] (false vocal cord) (figs. 970, 971, 987, 988). This appears as an elevation of the mucous coat of the lateral wall, prominent in its middle and anteriorly, fading away posteriorly. The ventricular fold contains the inferior free edge of the quadrangular membrane, that is, the ventricular ligament, and numerous glands.
The interval between the right and left ventricular folds, the vestibular slit [rima vestibuli] leads downward to a space between the planes of the ventricular and vocal folds, which extends on each side into the laryngeal ventricle [ventriculus laryngis (Morgagni*)] (figs. 970, 971, 987, 988). The latter is a little anteroposterior pocket of the mucosa reaching from the level of the arytsenoid nearly to the angle of the thyreoid cartilage, and undermining the ventricular fold; it opens into the cavity of the larynx by a narrow mouth limited above and below by the ventricular and vocal folds. From its anterior part a small diverticulum,
the ventricular appendix [appendix ventriculi laryngis] extends upward between the ventricular fold medially and the thyreo-arytsenoid muscle and thyreoid cartilage laterally. Many mucous glands open into it.
The appendix is occasionally so large as to reach the level of the upper margin of the thyreoid cartilage or even the great cornu of the hyoid bone. The laryngeal pouches of some of the apes are remarkably developed and appear to serve in affecting the resonance of the voice. In man, their function, besides that of pouring out the secretion of the glands located within their walls, is not known.
The vocal fold [plica vocalis] (or true vocal cord) (figs. 970, 971, 987, 988) is the thin edge of a full, lip-like projection, the vocal lip. The vocal folds correspond in antero-posterior extent to the vocal hgament, and stand nearer the median line than the ventricular fold. In colour the vocal folds are pearly white, excepting the anterior end of each, where there is a yellow spot [macula flava] produced by a little mass of elastic tissue (sometimes cartilage) in the ligament. The vocal lip [labium vocale] forms the floor of the ventricle and contains the upper part of the elastic cone, whose thickened free edge, the vocal ligament, lies in the
vocal fold and along the vocal muscle. The two vocal lips with the vocal folds and the intervening space, the rima glottidis, together constitute the soundproducing apparatus, the glottis.
Below the vocal folds and the medial surfaces of the arytenoid cartilages is a slit, the rima glottidis (figs. 970, 971, 988), the narrowest part of the laryngeal cavity, extending from the arytsenoideus transversus muscle posteriorly to the thyreoid cartilage in front. The portion of the rima between the vocal folds is known as the pars intermembranacea ; that between the arytsenoids the pars intercartilaginea. The rima glottidis in easy respiration is narrow and has the form of a long triangle; in laboured breathing it is widely open and lozenge-shaped.
Below the level of the vocal folds is the space called the inferior entrance to the glottis [aditus glottidis inferior] (fig. 988), which is narrow from side to side above, wide and circular in section below — altogether somewhat funnel-shaped. Its walls are formed by the elastic cone and by the arch and lamina of the cricoid cartilage. The lining mucosa is separated from the elastic cone by numerous glands and loose connective tissue, a condition favorable to the development of oedema; below it is continuous with the mucosa of the trachea.
root of the tongue with the epiglottic valleculse and glosso-epiglottic folds leading backward to the epiglottis; behind the latter, the triangular aperture of the larynx, bounded at the sides by the ary-epiglottic folds. Further lateralward appear the piriform recesses, the laryngeal portions of which lie as transverse fissures behind the laryngeal aperture. Within the aryepiglottic folds are seen the prominent corniculate tubercles on either side of the interarytaenoid commissure and just anterior, the variable cuneiform tubercles. Within the vestibule the epiglottic tubercle rises upon the anterior wall, while at the sides appear the ventricular folds overhanging the slit-like openings of the laryngeal ventricles. Below this level the vocal folds stand out on either side approaching nearer the median plane than do the ventricular folds and conspicuous by their pearly whiteness. The form and extent of the rima glottidis and of its divisions, the intermembranous and intercartilaginous parts, can be inspected. Far down, the cricoid cartilage and anterior wall of the trachea may appear and under favourable conditions a glimpse of the bifurcation of the latter can be obtained.
The mucous coat of the larynx [tunica mucosa laryngis] in general is covered by a ciliated epithelium; the vocal lips, and, exceptionally, small areas of the mucosa of the laryngeal surface of the epiglottis and the ventricular folds possess a covering of flat, non-ciliated cells. The attachment of the mucosa to the underlying parts is very firm about the vocal folds and dorsal side of the epiglottis, and loose in the ary-epiglottic folds, where much areolar tissue is present. In general the mucosa is pink in colour, becoming bright red over the epiglottic tubercle and edges of the epiglottis and fading over the vocal folds, which appear almost white.
Numerous mucous glands [glandulse laryngeal] occur about the larynx and are aggregated into groups in certain places. One cluster of anterior glands [gl. laryiifjoa- nnteriores] is found in front of and on the posterior side of the epiglottis; another, the middle glands [gl. laryngeae media;], is in the ventricular fold, in the triangular fovea of the arytfonoid curtilage and clustered about the cuneiform cartilage, while a third set, the posterior glands [gl. laryngea; posteriores], is disposed about the transverse arytajnoid muscle. Many glands pour their secretion into the appendix of the laryngeal ventricle, but there are none on or about the vocal folds. Lymphnodules of the larynx [noduli lymphatici laryngei] occur in the mucosa of the ventricle and on the posterior surface of the epiglottis.
Position and relations. — The larynx opens above into the pharynx by the aditu and in thiss region is connected with the hyoid bone. Below, its cavity leads into the trachea. Its position in the neck is indicated on the surface by the laryngeal prominence (Adam's apple). It stands in front of the fourth, fifth, sixth, and seventh cervical vertebrae; from these it is separated by the prevertebral muscles and the pharynx, into the anterior wall of which it enters. The integument and cervical fascia cover the larynx anteriorly in the middle line, while toward the side are the sterno-hyoid, sterno-thryeoid, and thyreo-hyoid muscles. The lateral lobe of the thyreoid gland and the inferior constrictor of the pharynx are in relation to it laterally, while further removed are the great vessels and nerves of the neck.
Peculiarities of age and sex. Position. — The larynx is placed high in the neck in foetal and infantile life and descends in later life. In a six-months foetus the organ is two vertebra higher than in the adult. (Symington.) The descent of the larynx has-been attributed to the vertical growth of the facial part of the skull, but this cause is questioned by Cunningham, who points out the high position of the larynx in the anthropoid apes, where the facial growth is more striking than in man; it appears also that the larynx follows the thoracic viscera in their subsidence, which, according to Mehnert, continues until old age. At birth the interval between the hyoid bone and thyreoid cartilage is relatively very small and increases but little during early life.
Growth and form. — The larynx of the new-born is relatively large and in contour more rounded than that of the adult. The organ continues to grow until the third year, when a resting period begins, lasting until about twelve years of age, during which time there appears to be no difference between the larynx of the male and that of the female. At puberty, while no marked change is observable in the larynx of the female, rapid growth accompanied by modification of form of the larynx is initiated in the male. The laryngeal cavity is enlarged, the antero-posterior diameter markedly increased; the whole framework becomes stronger; the thyreoid cartilage especially increases greatly in its dimensions, giving rise to the laryngeal prominence; the vocal folds are lengthened and thickened, the voice changing in quality and pitch. These changes are, for the most part, effected in about two years, but complete development is not attained before twenty to twenty-five years of age. Castration is known to influence the development of the larynx, for in the eunuch it has been found to resemble that of a young woman. The changes in the structure of the cartilages have already been described.
Dimensions. — In the male the distance from the upper edge of the epiglottis to the lower margin of \\u: cricoid is 70 mm.; in the female, 48 mm. The transverse diameter is 40 mm. in the nial(\ 'Ao mm. in the female. The greatest sagittal diameter is 40 mm. in the male, 37 mm. in the female. The vocal folds in the male measure relaxed about 15 mm., in the female, but 11 mm.; when stretched, about 20 mm. and 15 mm. respectively. '
The length of the rima glottidis in the quiescent state is on the average 23 mm. in' the male; 17 mm. in the female. In the male the pars intermembranacea measures 15.5 mm., the pars intercartilaginea, 7.5 mm. In the female these are 11,5 mm. and 5.5 mm. respectively. The rima may be lengthened by stretching of the vocal folds to 27.5 mm. in the male and 20 mm. in the female. (Moura.) In the male the width of the rima glottidis is 6-8 mm. in its widest part, but may be increased nearly to 12 mm.
Vessels and nerves (figs. 980, 985), — The arteries supplying the larynx are the superior and inferior laryngeal, which accompany the internal and inferior laryngeal nerves respectively, and the crico-thyreoid arteries (see pp. 538, 564).
The nerves of the larynx are the superior and inferior laryngeal branches of the vagus and also certain branches of the sympathetic. Taste-buds occur and are abundant in the mucosa of the posterior surface of the epiglottis. The innervation of the muscles has already been indicated, and the description of the course and relations of these nerves will be found in the chapter on the Peripheral Nervous System. It should be mentioned here, however, that the idea of sharply limited territories of innervation, not only for the mucosa, but for the muscles as well, has been brought into question by the researches of Semon and Horsley, E.xner, and others, which show that the distribution and functions of the laryngeal nerves are e.xtremely complex.
The development of the larynx. — The larynx is developed partly from the lower portion of the embryonic pharynx and partly from the upper portion of the trachea. The .cricoid cartilage represents the uppermost tracheal cartilage, while the thyreoid is formed by the fusion of four cartilages representing the ventral portions of the cartilages of the fourth and fifth branchial arches. The laryngeal muscles are derived from the musculature of these arches and consequently their nerve-supply is from the vagus. Whether or not the arytenoid and epiglottic cartilages are also derivatives of the branchial arches is uncertain, although it seems probable that they are.
THE TRACHEA AND BRONCHI
The tubular trachea (figs. 972, 989), or windpipe, extends from the larynx downward through the neck and into the thorax to end by dividing into two branches, the right and left bronchi [bronchus (dexter et sinister)], which lead to
Inferior vena cava
the lungs. These tubes are simple transmitters of the respiratory air. Their walls are, for the most part, stiff and elastic, consisting in large part of cartilage. While the_ general form of these tubes is cyhndrical, a rounded contour is presented by their walls only in front and at the sides, the posterior surface being flat. The inner surface of the walls of the tubes presents a succession of slight annular projections caused by the cartilaginous rings which enter into their structure. The calibre of the trachea varies at different levels, a cast of the lumen being in general spindle-shaped. Its sectional area is less than the combined sectional areas of the two bronchi. When the bifurcation of the trachea [bifurcatio tracheae] is viewed by looking down into its cavity, a sagitally directed keel, the carina tracheae (fig. 990), is seen standing between the openings which lead into the bronchi. Its position is a httle to the left of the mid-plane of the trachea in a slight majority of cases, or in the mid-plane in a large percentage.
Position and relations (figs. 972, 989, 1000). — The trachea lies in the median plane, extending from the level of the sixth cervical vertebra downward and backward, receding from the surface in following the curve of the vertebral column, and deviating a little to the right in approaching the level of the fourth thoracic vertebra, where it divides. Its lower end is fixed so that with elevation and descent of the larynx the tube is stretched and contracted, ■ changes in length which also result from extension and flexion of the head and neck. The mobility of the trachea is favored by its loose investment of connective tissue.
About half of the trachea lies in the neclj, but the extent varies with the length of the neck, the position of the head and with age; the trachea holds a lower position in adult life than in childhood and a still lower one in old age when the bifurcation may be as low as the sixth or seventh thoracic vertebra. In front and closely connected with it is the isthmus of the thyreoid gland, covering usually the second to fourth cartilages; anterior to this the cervical fascia and integuments. The cervical aponeurosis is attached to the upper margin of the sternum in two lamellae, with an interspace containing the venous jugular arch, a lymph gland, and some fat. Between these aponeuroses and the trachea is another space containing the inferior thyreoid veins and some tracheal lymph-glands, and sometimes a thyreoidea ima artery. The innominate artery occasionally crosses the trachea obUquely in the root of the neck. Behind the trachea, in its whole length, Ues the oesophagus, which in this part of its course inclines to the left. On either side are the great vessels and nerves of the neck, and the lobes of the thyreoid gland. The inferior laryngeal nerve lies in the angle between the (Esophagus and trachea.
Within the thorax the trachea lies in the mediastinum, enveloped in loose areolar tissue and fixed through strong fibrous connections with the central tendon of the diaphragm. The innominate artery and the left common carotid are at first in front and then at its sides as they ascend, while the left innominate vein and the remains of the thymus are further forward. The aortic arch is in contact with the anterior surface of the trachea near the bifurcation. On the right side are the vagus nerve, the arch of the vena azygos, the superior vena cava, and the mediastinal pleura; on the left, the arch of the aorta, the left subclavian artery, and the recurrent laryngeal nerve. A large group of bronchial lymph-glands [lymphoglandulae bronchiales] lies below the angle of bifurcation. The oesophagus is behind and to the left.
The bronchi take an obfique course to the hilus of the lung, where they branch. The right bronchus is nearer to the vertical in its course than is the left; it is also shorter and broader. These conditions, together with the position of the tracheal keel, explain the more frequent entrance of foreign bodies into the right than into the left bronchus. The asymmetrical course of the two bronchi is probably genetically associated with the position of the heart and aorta.
The azygos vein arches over the right bronchus, the vagus passes behind, and the right branch of the pulmonary artery crosses anteriorly below the level of the first (eparterial) branch of the bronchus. The aorta arches over the left bronchus and gains its posterior surface along with the cesophagus; the left branch of the pulmonary artery passes at first in front and then above the bronchus.
Dimensions. — On account of their elasticity considerable difficulty is met with in obtaining accurate measurements of the air-tubes. The length of the trachea is given at 95-122 mm.; its transverse diameter 20-27 mm. ; the sagittal diameter 16-20 mm. The right bronchus has a length of 25-34 mm.; the left, 41-47 mm. The transverse diameter of the right is 18 mm.; of the left, 16 mm. The angle of bifurcation of the trachea varies from 56° to 90°, the mean being 70.4° a wide angle corresponding to the breadth of the thorax of man. The right bronchus makes an angle of 24.8° with the median plane; the left, 45.6°.
Over 20 years, female 13 to 16 mm.
Structure of the trachea and bronchi (figs. 978, 988, 989, 991).— The walls of the trachea and bronchi are composed of a series of cartilages having the form of incomplete rings, held together and enclosed by a strong and elastic fibrous membrane. Posteriorly, where the rings are deficient, this membrane remains as the membranous wall [paries membranacea] ; between the cartilages it constitutes the annular ligaments [ligg. annularia (trachealia)].
A tracheal cartilage [cartilago trachealis] comprises a little more than twothirds of a circle. Its ends are rounded, its outer surface flat, while the inner surface is convex from above downward; the upper and lower margins are nearly parallel. The cartilages are from sixteen to twenty in number. The first is usually broader than the type, and is connected by the crico-tracheal ligament with the cricoid cartilage. Sometimes these two cartilages are in part continuous. The last cartilage is adapted to the bifurcation of the trachea and presents at the middle of its lower margin a hook-hke process. This turns backward between the origins of the bronchi, and in the majority of cases gives a cartilaginous basis to the tracheal carina. Some of the tracheal cartilages vary from the type by bifurcating at one end. The cartilages keep the lumen of the trachea patent for the free passage of the air. Calcification occurs as with the laryngeal cartilages, but much later in life.
A mucous coat [tunica mucosa], soft and pinkish-white in colour, covers the inner surface of the trachea; posteriorly it is thrown into longitudinal folds. Mucous secreting tracheal glands [gl. tracheales] are present in the elastic submucous coat [tela submucosa] between the cartilages and at the back of the trachea. A thin layer of transversely disposed smooth muscle-fibres, stretching between the ends of the cartilages in the posterior wall, constitutes the muscular
coat [tunica muscularis]. Contraction of this trachealis muscle, as it is more properly named, causes the ends of the tracheal cartilages to be approximated and the lumen of the wind-pipe to be diminished.
the gullet.
Vessels and nerves. — The arteries supplying these air-tubes come from the inferior thyreoid and from the internal mammary by its anterior mediastinal or broncliial branches. Venous radicles come together in the annular ligaments and join lateral veins on either side, which empty the blood into the plexuses of the neighbouring thyreoid veins.
Lyinph-vessels are abundant, and are disposed in two sets, one in the mucosa, another in the submucosa. They drain into the tracheal, bronchial and oesophageal lymph-glands. Neri'es are provided by the vagus direct, by the inferior laryngeal, and by the sympathetic.
The lungs [pulmones], the essential organs of respiration, are constructed in such a way as to permit the blood to come into close relation with the air (fig. 992). Their genetic connection with the entodermal canal has already been indicated (see also p. 1099). In plan of structure the lung has been compared with
b.r. Respiratory bronchiole, d.al. Alveolar duct; a second alveolar duct is shown cut off. a,a. Atria, s.al. Alveolar saccule, a.p. Alveolus, art. Pulmonary artery with its branches to the atria and saccules, v. Pulmonary vein with its tributaries from the pleura (1), the alveolar duct (2), and the place where the respiratory bronchiole divides into the two alveolar ducts (3).
a gland, since it is composed of a tree-like system of tubes terminating in expanded spaces. Closely associated with the system of tubes are certain blood-vessels, some of which take part in nourishing the organ, others participate in its special mechanism.
The lungs are two in number, and lie one on either side of the thoracic cavity, separated by a partition known as the mediastinum (figs. 993, 997, 1000). Serous membranes covering the latter right and left are parts of two closed sacs, the pleurse, each of which is reflected about a lung and the neighbouring chest-wall after the manner of serous membranes in general. The space enclosed within the sac-walls is the pleural cavity, genetically a subdivision of the ccelom.
Form (figs. 994, 998). — The lung is pyramidal or conical in form, with the base [basis pulmonis] below and resting on the diaphragm, and with apex [apex pulmoni.s] above, in the root of the neck. Two surfaces, costal and mediastinal, are described. The broad convex costal surface [fades costalis] is directed against
the thoracic wall in front, laterally and behind, and is marked by grooves corresponding to the ribs. The mediastinal surface [f acies mediastinalis] is concave and presents a contour adapted to structures of the mediastinum (fig. 994). A special concavity on this surface, known as the cardiac fossa, corresponds to the prominence of the heart and is deeper in the left lung than in the right. Above and behind the cardiac fossa is a depression, the hilus of the lung [hilus pulmonis], where the bronchus and pulmonary vessels and nerves together constituting the root of the lung [radix pulmonis], enter and leave. Near the posterior edge of the mediastinal surface is a groove, which ascends and turns forward over the hilus ; the groove of the left lung is adapted to the cylindrical surface of the aorta; that of the right, the vena azygos. A well-marked subclavian sulcus [sulcus sub-
FiG. 993. — Horizontal Section of the Thorax op a Man, aged Fifty-seven, at the Level OP the Roots of the Lungs, seen prom Above. (J. S.) (Quain.) X 1. A. A. Ascending aorta. A.M. Anterior mediastinum. A.V. Azygos vein. D.A. Descending aorta. E. Eparterial bronchus. I. Superior lobe of lung. L.B. Left bronchus. L.P. Left phrenic. L.P.V. Left pulmonary vein. L.V. Left vagus. (Es. CEsophagus. P A. Pulmonary artery. P.C. Pericardial cavity. R.B. Right bronchus. R.P.A. Right branch of pulmonary artery. R.P.C. Right pleural cavity. R.P.N. Right phrenic. R.P.V. Right pulmonary vein. R.V. Right vagus. S. Inferior lobe of lung. Sc. Scapula. T.D. Thoracic duct. 3, 4, .5, 6, 7. Corresponding ribs.
clavius] extends upward on this surface to the apex, corresponding on the right side to the lower part of the trachea and right subclavian artery, on the left tothe left subclavian artery alone. Further forward is a groove adapted in the right lung to the superior cava; in the left to the left innominate vein. The lung is not in actual contact with these several structures, but is separated from them by the mediastinal pleura. The mediastinal surface passes gradually into the costal surface posteriorly, there being no proper posterior edge. Where the mediastinal and costal surfaces meet in front, a sharp anterior margin [margo anterior] exists (fig. 997). In the right lung this runs down in a gentle curve to turn lateralward in the inferior margin. In the left lung the anterior margin is cut into by a wide cardiac notch [incisura cardiaca], which is occupied bj' the heart in the pericardium as it is pressed toward the anterior thoracic wall. The cardiac notch is separated from the inferior margin by a little tongue of lung substance, the pulmonary lingula [lingula pulmonis].
The base of the lung (fig. 994) presents the diaphragmatic surface [facies diaphragmatica] concave and oblique in adaptation to the dome of the diaphragm. It is limited by a sharp inferior margin [margo inferior], which follows the curves of the mediastinal and costal surfaces, and fits into the angle between the diaphragm and thoracic wall.
The apex (figs. 994, 997, 998) is rounded and points upward with an inclination forward and medially, accommodating itself to the structures within and about the superior aperture of the thorax.
A deep interlobar fissure [incisura interlobaris] (figs. 994, 998), reaching through the lung substance nearly to the hilus, divides each organ into a smaller superior lobe [lobus superior] and a larger inferior lobe [lobus inferior]. The interlobar fissure runs downward and forward beginning a short distance below the apex, and reaching the base near the anterior margin in the left lung, somewhat further back in the right lung. From the obliquity of the plane of the fissure it will be noticed that the inferior lobe reaches posteriorly to within a short distance of the apex, and includes the greater part of the back and base of the lung, while the superior lobe takes in the anterior margin and apex. The presence of a middle lobe [lobus medius] disturbs the symmetry of the right lung. This results from a deep, nearly horizontal incisure cutting through the lung somewhat below its middle, and extending between the anterior margin and the main interlobar fissure, which it reaches at about the level of the axillary line.
Diaphragmatic surface
Besides possessing the individual peculiarities mentioned, the two lungs further differ from each other in general form and weight, the right lung being considerably broader and heavier than the left. The difference in length maintained by some anatomists, even if it prove constant, must be slight and of httle practical importance. These difJerenoes seem to foUow the asymmetry of the vault of the diaphragm and the position of the heart.
The hilus (fig. 994), already mentioned as situated on the mediastinal surface, presents in the left lung a raquette-shaped outline. Its average height is about 8.8 cm. (Luschka);it extends over both lobes. The hilu of the right lung, rather four-sided in outline and shorter than that of the left, is related to the three lobes. The entering structures, constituting the root of the lung (figs. 989, 993, 994), include the bronchus, pulmonary artery and veins, bronchial vessels, lymphatic vessels and glands, and pulmonary nerves. These are bound together by connective tissue and invested by the pleura. The bronchus is in the posterior and upper part of the root; the pulmonary vessels he anteriorly, the veins below the arteries.
The surface of the lung is marked off in polygonal areas of different sizes (secondary lobules) by lines containing pigment. The pigmentation is especially deep on the lateral surface along the furrows corresponding to the ribs.
THE BRONCHIAL TUBES
Branching of the bronchial tubes (fig. 995) . — Each bronchus, from its origin at the bifurcation of the trachea, takes an oblique course to the hilus, and then continues in the lung as a main tube, extending toward the posterior part of the base. These stem-bronchi are curved, probably in adaptation to the heart, the right hke the letter C and the left like an S. Throughout their course the stem-bronchi give off in monopodic fashion collateral branches, the bronchial rami [rami bronchiales], and these, branching in a similar way, reach all parts of the lung.
The first bronchial ramus of the right stem-bronchus arises above the place where the latter is crossed by the pulmonary artery and is named the eparterial bronchial ramus [ramus bronohialis eparterialis]; it supphes the superior lobe of the right lung, sending a special branch to the apex. All other bronchial rami, whether in the right or left lung, take origin from the
Position of median plane
stem-bronchi below the level of the crossing of the pulmonary artery and are called hyparterial bronchial rami [rami bronchiales hyparterialesj. The second bronchial branch of the right lung goes to supply the middle lobe, while several bronchial branches enter the inferior lobe. On the left side, the first bronchial branch arises below the crossing of the pulmonary artery, and goes to supply the supei-ior lobe, providing it with an apical ramus. The other branches are given to the inferior lobe.
Structure of the bronchial rami. — The larger bronchial rami contain in their walls both C-shaped and irregular plates of cartilage, the latter gradually replacing the former as the branches become smaller. The membranous wall is lost and plates of cartilage are disposed on all sides. The mucosa, with ciUated epithehum, is thrown into longitudinal folds covering bundles of elastic fibres of the membrana propria. Next to the latter is a continuous layer of smooth muscle-fibres circularly arranged. Mucous secreting bronchial glands [gl. bronchiales] are present as far as tubes of 1 mm. diameter; here the cartilages also disappear.
To W. S. IVIiller is due the credit of having greatly increased our knowledge of the finer structure of the lung and for having presented the conception of the primary lung lobule now generally accepted by anatomists. Some of the chief results of MiUer's work are embodied in
lymph vascular systems of the lungs and pleurse.
Through further branching of the bronchial rami a great number of very fine bronchioles [bronchioli] are reached, whose walls possess a weak muscle layer and are lined by mucosa having an epithelium of flattened non-ciliated cells. These, subdividing, give rise to the respiratory bronchioles [bronchioh respiratorii], the walls of which are beset with alveoli (fig. 992). From the respiratory bronchioles arise the alveolar ducts [ductuli alveolares], or terminal bronchi, each of which leads to a group of air-spaces, called atria, each of which again communicates with a second series of air-spaces, tlie air-sacs (alveolar sacs or infundibula), whose walls are pouched out to form numerous pulmonary alveoli [alveoli pulmonum].
Aeby divided the bronchial branches into two sets, according to their relation to the pulmonary artery. The branch arising above the place where the pulmonary artery crosses the stem-bronchus he named the eparterial bronchus, and those arising below the crossing he called hyparterial. An eparterial bronchus exists only on the right side ; all other branches are hyparterial. Since the eparterial supplies the superior lobe of the right lung and no eparterial branch is present on the left side, Aeby concluded that the left lung had no lobe homologous with the superior lobe of the right lung. He compared the middle lobe of the right with the superior lobe of the left lung. The collateral branches of the stem-bronchi arise in a dorsal and ventral series in the lower mammals, and the same arrangement, though less obvious, obtains in man. According to the views of Aeby and Hasse, the first ventral branch of the right side is distributed to the middle lobe, while the remaining three ventral and all the dorsal lateral branches are given to the inferior lobe. On the left side, the first ventral branch is given to the superior lobe; the other ventral branches and the dorsal branches are distributed to the inferior lobe.
in migrating to the bronchial trunk.
Narath considers the division of bronchial branches in accordance with their relation to the pulmonary artery as of no great morphological significance. He attributes the apparent differences on the two sides to a shifting in position of homologous branches. Thus, Narath considers that the eparterial bronchus of Aebj' has become the first dorsal lateral branch by displacement above the pulmonary artery and that it is homologous with an apical branch of the left side, which retains its primitive origin from the first ventral branch (fig. 996) . Narath's conception of the migration of the bronchial branches is supported by the results of Huntington's extensive stiulii's of the bronchial tree in mammals.
The physical properties of the lungs. — The average dimensions in the adult male are as follows: Height of the lung is given at 2.5-27 cm., the greatest sagittal diameter at 16-17 cm., and the greatest transverse measurement as 10 cm. for the right and 7 cm. for the left. The volume of the lungs when well expanded is 6500 c.c. (Merkel.) The loeight of the lungs can be found only approximately on account of the presence of blood and mucus. In the adult male the weight of both lungs is given as 1300 gm.; female, 1023 gm. The weight of the right lung compared with the left is as 11 is to 10. Ried and Hutchinson found the weight of the lungs compared with that of the body as 1 :37 (male), 1 :43 (female); in the foetus at term, 1 : 70. After respiration has been established, the lung, if placed in water, will float. Its specific gravity is between 0.345 and 0.746, (Rauber.) The fcetal lung contains no air and is heavier than water. Its specific gravity is 1.045 to 1.056. (Ivrause.) Lung tissue, free of air, with vessels moderately filled, has likewise a specific gravity of 1.045 to 1.056. (Vierordt).
the lungs from the atmosphere.
In consistence the lung is soft and spongy, and when compressed between the fingers, emits a crackling sound. Among the physical properties the elasticity of the lung is quite remarkable: Under ordinary conditions the pressure of the air in the lung keeps the alveoli and the organ as a whole distended, but when the pleura has been opened and the air pressure equalised without and within, the lung collapses.
Topography. — The apices of the lungs extend upward as high as the first thoracic vertebraa level considerably higher than the superior margin of the sternum (figs. 997, 998). The sub, clavian vein and artery and the brachial plexus, together with the anterior scalene muscle, control to a certain degree the height reached. There seems to be no constant difference between the levels attained by the apices of the two lungs. The extent to which the apex rises above the clavicle is rarely more than 3.5 cm. (Merkel), and will, of course, vary with individual differences in the position and form of this bone. The average is not over 2.5 cm. (1 in.).
The base of the lung, resting on the diaphragm, is separated by that thin partition from the underlying abdominal viscera: thus beneath the base of the right lung is the right lobe of the liver, while under the left lung are the left lobe of the liver, the fundus of the stomach, and the spleen. The position of the apex changes very little in respiration, and the same holds true for
, The parietal pleura is shaded and outlined in black.
the hinder bulky part of the lung. The latter rests against the side of the vertebral column in the deep hollow of the angles of the ribs, and reaches below to the level of the eleventh costovertebral joint (fig. 998). The anterior margins (fig. 997) descend in curves from behind the sterno-clavicular joints, and run near together a little to the left of the median line. At the level of the sixth costo-sternal junction the anterior margin of the right lung turns lateralward to follow the sixth costal cartilage. The anterior margin of the left lung turns lateralward a,long the fourth costal cartilage as far as the para-sternal line, descending in .a curve to the lingula and thus forming the cardiac incisure. The positions of the inferior margins (figs. 997, 998) of the two lungs are practically alike in their positions. Each extends in a curve covyex downward, behind the sixth costal cartilage in its entire length, crosses the costo-chondral junction of the sixth rib to the superior margin of the eighth rib in the axillary hne, and so to the ninth or tenth rib in the scapular line, whence they run horizontally medialward to the eleventh costo-vertebral joint. *
* These relations are the mean between the conditions observed in the cadaver and as found by physical examination of the hving. In old age the inferior margins of the lungs reach a level one or two intercostal spaces lower than is the case in adult life (Mehnert).
The interlobar fissure (fig. 998) begins about 6 cm. below the apex of the lung at the level of the head of the third rib. With the arm hanging at the side, a hne drawn across the back from the third thoracic spine to the root of the scapular spine would indicate the course of the upper part of this fissure. (Merkel.) Thence it passes downward and around the chest to the end of the sixth bony rib in the mammillary line. Merkel points out the use of the root of the scapular spine as a landmark for finding the limits of the lobes posteriorly: with the arm hanging at the side all above this spot is superior lobe; aU below it the inferior. The short fissure of the right lung begins at the main interlobar fissure in the axillary line, about the level of the fourth rib or fourth interspace, and passes nearly horizontally to the anterior margin of the lung at the level of the fourth costal arch.
The roots of the lungs are placed opposite the fifth, sixth, and seventh thoracic vertebrae. The right root lies behind the inferior vena cava and under the arch of the azygos vein; the left root is beneath the aortic arch and in front of the thoracic aorta. On the front and back are the pulmonary plexuses, anterior and posterior. The ligament of the pleura goes from the lower edge of the root.
Vessels and nerves of the lungs. — The bronchial arteries (see p. 588), belonging to the systemic system, carry blood for the novirishment of the lungs. They arise from the aorta or from an intercostal artery, two for the left lung and one for the right, and, entering at the hilus,
The pleura is represented as in Fig. 997.
reach the hinder wall of the main bronchus. The bronchial arteries accompany the bronchi, whose walls they supply, as far as the distal ends of the alveolar ducts, beyond which they do not go. These vessels also supply the lymph glands of the hilus, the walls of the large pulmonary vessels, and the connective-tissue septa of the lung. Bronchial veins (see p. 664), anterior and posterior, arise from the walls of the first two or three divisions of the bronchi and end in the innominate and the azygos or in one of the intercostal veins; those arising from the walls of the smaller tubes, including the alveolar ducts, join the pulmonary veins. The pulmonary artery (see p. 528), entering the hilus in a plane anterior to the bronchus, tm-ns to the posterior aspect of the main-stem, following its branches and their subdivisions to the lobules. Entering the lobule, the last branch of the vessel gives off as many twigs as there are atria (fig. 992), and these twigs end in dense capillary nets in the walls of the alveoli. Here the venous blood brought by the pulmonary artery, separated from the air in the alveolus only by a thin septum, is changed to arterial blood in the respiratory process. According to Miller, anastomosis between the branches of the pulmonary artery are exceptional. Anastomosis between the bronchial and pulmonary arteries has been claimed, but the connection apparently existing between these vessels is through the radicles of the bronchial veins which join the pulmonary veins. The pulmonary venous radicles begin at the capillary networks and drain the arterial blood into the pulmonary veins, which run between adjacent lobules and which receive also
blood coming from the capillary network of the pulmonary pleura and from the capillary network of the bronchi (fig. 992). Thus it wiU be seen that while the pulmonary vein carries mainly arterial blood, it carries also some venous blood. The pulmonary veins (see p. 529) follow the bronchial tree on the side opposite the arteries to the hilus, where, having converged to two large trunks located in the root of the lung below the plane of the artery, they pass to the left atrium. The pulmonary veins have no valves.
Lymphatics. — Miller has found the lymphatic vessels forming a closed tube system in the walls of the bronchi, in the pleura, and along the branches of the pulmonary artery and veins. Within the lung numerous pulmonary lymph-glands [lymphoglandulse pulmonales] are found chiefly at the places of branching of the larger bronchi [lymphoglandulae bronchiales[. Scattered along the latter, as well as associated with the branches of the pulmonary artery and vein, are found masses of lymphoid tissue. Deposits of carbonaceous matter in the lymphoid structures of the lung are present, except in early infancy ; the amount increases with age.
Nerves. — The vagus and sympathetic contribute to form the pulmonary plexuses in front and behind the root of the lung, from which branches go to accompany bronchial arteries; a smaller number accompany the air-tubes (see p. 957).
Variations. — Congenital absence of one or both lungs has been observed. Variations in the lobes are not uncommon — four for the right and three for the left lung has been recorded. An infracardiac lobe, as found in certain mammals, sometimes occurs; an infracardiac bronchus is, however, constant in man. More or less complete fusion of the middle and upper lobes of the right lung is not rare. The lungs may be symmetrical, with two lobes each, the apical bronchus of the right springing from the first ventral bronchus, as is normal for the left lung (Waldeyer, Narath) ; or the lungs may have three lobes each, the apical bronchus of the left arising from the main bronchus. The apical bronchus of the right lung may arise from the trachea, an origin that is normal in the hog and other artiodactyls.
Development of the lungs and trachea. — The first indication of the trachea and lungs appears in embryos of about 32 mm. as a trough-like groove in the ventral wall of the upper part of the oesophagus, communicating above with the pharynx. Later the groove becomes constricted oi? from the oesophagus, the constriction extending from below upward, so that a tube is formed which opens into the pharynx above. The lower end of this tube soon becomes bilobed, and the lobes, elongating, give rise to additional lobes, of which there are primarily three in the right side and two in the left. The upper unpaired portion of the tube becomes the trachea, while the lobed lower portion gives rise to the bronchi and lungs, the complicated structure of the latter being produced by oft-repeated branchings of the bronchi.
Thoracic cavity [cavum thoracis] is the term used to denote the space included by the walls of the thorax and occupied by the thoracic viscera. These are, on each side, the lung, surrounded by the pleural cavity, and in the middle the pericardium and heart, great vessels, trachea and oesophagus, all closely associated and forming a dividing wall, the mediastinal septum, standing between the right and left sides of the thoracic space.
The limits of the thoracic space are given by the skeletal parts of the thorax together with the ligaments involved in the articulations and the muscles and membranes interposed between the bones. The arched diaphragm forms the inferior limit; and the barrier presented by the scalene muscles and the cervical fascia makes the superior boundary, which, it is to be observed, lies above the plane of the superior aperture of the thorax and therefore in the base of the neck. These boundaries are approached by the extension of the pleural cavities; yet there intervenes the parietal layer of the pleural sac which is connected with the thoracic walls by loose connective tissue, the endothoracic fascia [fascia endothoracica].
The form of the thoracic space departs from the external contour of the thorax chiefly through the projection into it of the ridge made by the succession of centra of the thoracic spine, and by the presence on either side of the latter of the broad, deep pulmonary sulcus. On account of these features a transverse section of the thoracic space is somewhat heart-shaped, but, however, much compressed anteroposteriorly (fig. 993).
The arch of the diaphragm on the right side rises to the level of the spinous process of the seventh thoracic vertebra; on the left, to the level of the eighth thoracic spinous process. At its circumference the diaphragm is in contact to a variable extent above its origin with the inner surfaces of the costal arches. In the lower part of this zone a connection exists between the muscle and the thoracic wall through a continuation of the endothoracic fascia; in the upper part, the phrenico-costal sinus (see p. 1237) intervenes. The level reached by this deepest part of the pleural cavity is lower than the summit of the peritoneal cavity, so they overlap to a considerable extent.
The pleura (fig. 993) is a closed serous sac, which invests the lung (pulmonary pleura), and lines the inner surface of the thoracic walls (parietal pleura). The pleural cavity [cavum pleurae] is the capillary space enclosed by the walls of the sac containing a little fluid which lubricates the apposed surfaces of the pulmonary and parietal membranes. There are two pleurae, one in relation to each lung, completely separated by a sagittal partition, the mediastinum.
FiQ. 999. — Plettral Cavity Opened From in Front. 1, first rib; 2, manubrium sterni; 3, acromial extremity of clavicle; 4, xiphoid process, 5, linea alba; 6, m. transversus abdominis; 7, seventh rib; 8, sternocleidomastoid m.; 9, anterior scalene m.; 10, larynx; 11, thyreoid gland; 12, deep layer of cervical fascia in front of the trachea; 13, corresponds to upper part of anterior mediastinal cave; 14, pleural cupola; 15, mediastinal pleura; 16, lower margin of costal pleura; 17, pericardium; 18, superior lobe of lung; 19, middle lobe of right lung; 20, inferior lobe of lung; 21, diaphragm. (RauberKopsch.)
The pulmonary pleura [pleura pulmonalis] forms a smooth glistening coat over the outer surface of the lung, with the tissue of which it is inseparably connected. At the hilus the pulmonary pleura passes from the mediastinal surface of the lung to cover the root above, in front, and behind, and becomes continuous medialward with the parietal pleura of the mediastinum. Below the root of the lung the pleura is reflected medialward in a double layer as the pulmonary ligament [Hg. pulmonale] (fig. 994).
This presents anterior and posterior surfaces and three margins; the base is mostly free, and directed toward the diaphragm, with which it is connected at its medial end; the apex is at the lung root, one margin is next to the lung, and the other joins the mediastinal pleura.
The parietal pleura [pleura parietalis] is divided, according to the regions of the chest with which it is associated, into the costal, diaphragmatic, and mediastinal pleura. The costal pleura [pleura costahs] hnes the thoracic wall, to which it is bound not very firmly by the endothoracic fascia. It covers incompletely the back of the sternum and extends laterally upon the ribs and "intercostal muscles. Posteriorly beyond the angles of the ribs it passes over the anterior rami of the thoracic nerves and intercostal vessels, the heads of the ribs, and the sympathetic trunk to the vertebral column; here it becomes continuous with the mediastinal pleura. Above, the pleura reaches beyond the superior margin of the sternum into the root of the neck, and in the form of a dome, the cupola of the pleura [cupola pleurae], is adapted to the ape.x of the lung. It is supported by processes of the deep cervical fascia, and by a fibrous aponeurosis known as Sibson's fascia, coming from the scalenus minimus muscle and connected with the inner margin of the first rib. In relation to the pleural cupola are those structures already described as grouped about the lung apex: the brachial plexus, subclavian artery, anterior scalene muscle, and the subclavian vein, and, on the left side, in addition, the thoracic duct.
Below, the costal pleura is continuous with the diaphragmatic pleura [pleura diaphragmatica], which adheres closely to the thoracic surface of the diaphragm and covers it, excepting the pericardial area and where the diaphragm and thoracic wall are in contact.
Phrenic nerve
[pleura pericardiaca], to which it is closely adherent, and also the other structures of the mediastinum, with which the two layers are less firmly connected. Above the lung root the mediastinal pleura stretches directly from the spine to the sternum; but at the level of the root and below it, it is reflected laterally to the pulmonary pleura covering the root in front and behind and forming the pulmonary ligament.
The right mediastinal lamina covers (fig. 1000) the right innominate vein, the superior vena cava, the vena azygos, the trachea, the innominate artery, the right vagus and phrenic nerves, and the oesophagus. The left lamina lies against the left innominate vein, the arch of the aorta the left subclavian artery, the thoracic aorta, the left phrenic and vagus nerves, and the cesophagus. About the base of the heart-sac are a number of adipose folds [plica? adiposis) projecting from the pleura, the surfaces of which present some villous processes, the pleural villi [villi pleurales] ; the latter also occur on the pulmonary pleura along the inferior margin of the lung.
The lines of pleural reflexion are of practical importance (figs. 997, 998, 1003). Posteriorly, the costal pleura simply turns forward in a gentle curve to become the mediastinal pleura, but anteriorly and inferiorly the membrane is folded upon itself, leaving intervening capiUary spaces, the sinuses of the pleura [sinus pleurtT;]. Such a space is present where the costal pleura is reflected upon the diaphragm, the sinus phrenicocostalis, the fold of the pleura occupying the upper part of the angle between the thoracic wall and diaphragm, the endothoracic fascia
filling the lower part. The inferior margui of the lung enters this sinus a variable distance in iuspiration. The line of the costo-diaphragmatio reflexion begins in front on the sixth costal cartilage, which it follows, descending obliquely to cross the seventh interspace in the mammillary line. The greatest depth reached is at the tenth rib or interspace in the axillary line. The line of reflexion then continues around the thorax ascending slightly to the twelfth costovertebral joint.
Lines of pleural reflection red, boundaries of the lungs and pulmonary lobes black.
1, sixth cervical vertebra; 2, first thoracic vetebra; 3, twelfth thoracic vertebra; 4, first lumbar vertebra; 5, manubrium sterni; 6, body of sternum; 7, xiphoid process; 8, first rib; 9, cartilage of seventh rib; 10, 11, 12, tenth, eleventh and twelfth ribs. (Rauber-Kopsch.)
of the first lumbar vertebra. Such a possibility must be considered in operating upon the kidney. The lines of reflexion of the costal pleura backward to the mediastinal pleura behind the sternum begin opposite the sterno-clavicular joints, descend obhquely medialward to the level of the second costal cartilage, whence they run near together or in contact, but to the left of the medianHline, to the level of the fourth cartilage. The reflexion on the right side continues from the sternum as far as the sixth rib cartilage, there turning laterally into the costo-diaphragmatic reflexion. The line on the left side, in the region of the cardiac notch (from the fourth
to the sixth cartilages), is a little to the left of the sternal margin. From this position of the line of reflexion it happens that there is left uncovered by pleura a small area of the pericardium which is in contact immediately with the chest-wall. A reduplication of the pleura takes place along the anterior line of reflexion, and into the sinus costomediastinalis so formed the thin anterior margin of the lung advances in inspiration. That part of the left costo-mediastinal sinus which is in front of the pericardium is not completely filled by the margin of the lung. Although the positions of the lines of reflexion of the mediastinal pleura here described are those
variation of the anterior lines, as determined by Tanja, are indicated in fig. 1003.
Blood-vessels. — The vascular networks of the pulmonary pleura are derived from the bronchial artery and probably to some extent from the pulmonary artery which in the dog, is the only source of blood supply. The venous radicles arising from the network enter the lung. (See radicles of the pulmonary vein on page 1235.) The parietal pleura is supplied by arteries from several sources: internal mammary, intercostals, phrenics, mediastinal, and bronchial. The veins correspond to the arteries. The lymphatics of the pulmonary pleura form rich networks without definite relations to the lobules of the lung. They accompany the radicles of the pulmonary veins and drain into the bronchial lymph-glands. In the parietal pleura lymph-vessels are present most abundantly over the interspaces; they empty into the sternal and intercostal glands. (See p. 728.) The nerves supplied to the pulmonary pleura are branches from the pulmonary plexus; to the parietal pleura, from the intercostals, vagus, phrenic, and sympathetic.
MEDIASTINAL SEPTUM
The two pleural cavities are separated from each other by the mediastinal septum [septum mediastinale] (fig. 1000). This is a sagittal partition extending from the superior aperture of the thorax to the diaphragm between the thoracic vertebrae and the sternum, its free surfaces, right and left, formed by the mediastinal layers of the pleurae. It is composed of the pericardium and heart and of structures which, for the most part, extend in a longitudinal direction through the thoracic cavity.
These include the oesophagus together with the vagus nerves, the thoracic duct, thoracic aorta and azygos vein; the trachea, the pulmonary vessels and the arch of the aorta with its great branches, the superior vena cava and its tributaries and the phrenic nerves; the thymus gland, internal mammary vessels and many lymph glands throughout the septum. These structures are packed together and supported by intervening connective tissue. Moreover, the connection of the sheaths of the great vessels with processes of the cervical fascia and the fixation of the pericardium to tlie diaphragm, give to the latter a strong support. Owing to the position of the heart, the two sides of the septum are not symmetrical, and it follows from the bulging of the left surface of the mediastinal septum that the left pleural cavity is encroached upon.
The name mediastinal cavity has been applied to the two regions of the mediastinal partition which find themselves located, the one in front, the other behind the plane of the heart. There is in reality no cavity, the term being used in this connection merely to donate space. Between the two spaces are interposed the pericardium and heart, the great vessels, trachea and bronchi. The anterior mediastinal cavity [cavum mediastinale anterius] is small. Its lateral limits are formed by the mediastinal layers of the pleurse, right and left, which are reflected backward from the costal pleurae of the anterior thoracic wall. The space is occupied by loose connective tissue, surrounding the thymus gland, the internal mammary vessels and a number of lymph-glands.
Recalling the lines of reflexion of the mediastinal pleurfe as above described, the form, position and extent of this space as observed from in front, will be understood; it is widest behind the inferior end of the body of the sternum and fifth and sixth costal cartilages of the left side {area inlerpleurica inferior) ; narrowest where the mediastinal layers are approximated behind the body of the sternum, broader again where the laminae deviate posterior to the manubrium sterni {area inlerpleurica superior). In the latter space lies the thymus gland and the superior portions of the internal mammary vessels. In the area interpleurica inferior the pericardium comes into immediate contact with the anterior thoracic wall, and here the inferior portions of the left internal mammary vessels are found. The lymphatic vessels and glands of the anterior mediastinal space belong to the anterior mediastinal and sternal groups.
The posterior mediastinal cavity [cavum mediastinale posterius] (fig. 1000), hmited behind by the thoracic vertebrae and laterally by the mediastinal layers of the pleurae where they are reflected forward from the costal plem-ae of the posterior thoracic walls, is elongated and of more regular form than the anterior space. It includes the thoracic aorta, the oesophagus and vagi, the thoracic duct, azygos vein and lymph glands.
Within this space are also to be found the origins of the right intercostal arteries, the hemiazygos and, when present, the accessory hemiazygos veins, terminations of some of the left intercostal veins and the greater splanchnic nerves. The lymph glands belong to the posterior mediastinal group.
the pericardium. It extends" between the first four thoracic vertebrse behind and the manubrium sterni in front, and contains the arch of the aorta and the great vessels arising from it, the innominate veins, and the upper part of the superior vena cava, the thoracic duct, the lower portion of the trachea, and a portion of the oesophagus, the phrenics, vagi, left recurrent and cardiac nerves, and the thymus gland.
From the superior mediastinum the other three divisions of the space extend downward. The anterior mediastinum is identical with that part of the anterior mediastinal cavity which is below the level of manubrium sterni. The middle mediastinum lies between the layers of the mediastinal pleura? in front of the root of the lungs; it contains the heart, enclosed in the pericardium, and the phrenic nerves. The posterior mediastinum corresponds to that portion of the posterior mediastinal cavity which extends below the plane of the fifth intervertebral fibro-cartilage.
References for Respiratory System. A. External nose and nasal cavity.
Kallius, in von Bardeleben's Handbuch; Zuckerkandl, Normale u. path. Anatomie d. Nasenhohle, Bd. 1, Wien, 1893; {Develo-pvient) His, Archiv f. Anat. u. Phys., 1892; Killian, Arch. f. LaryngoL, Bd. 4, 1896; Schaeffer, Jour. MorphoL, vol. 21, 1910; {Concha) Peter, Arch. f. mikr. Anat., Bd. 60, 1902; {Paranasal sinuses) Bartels, Zeitschr. f. Morph. u. Anthrop., Bd. 8; Turner, Accessory Sinuses of the Nose, Edinburgh, 1901; {Anthropology) Hoyer, Morph. Arbeiten, vol. 4, 1894. B. Larynx. Gerlach, Anat. Hefte, H. 56; {Development) Lisser, Amer. Jour. Anat., vol. 12; {Ossification) Scheier, Arch. f. mikr. Anat., Bd. 59. C. Lungs. {Structure; vascular supply) Miller, Arch. f. Anat. u. Entw., 1900; Amer. Jour. Anat., vol. 7; Schultze, Sitzb. AkadWiss., Berlin, 1906; {Development) Flint, Amer. Jour. Anat., vol.6 {Topographical) Mehnert, Topogr. Altersveranderungen d. Atmungsapparatus, Jena, 1901. D. Pleura. Ruge Morph. Jahrb. Be. 41.
A. THE URINARY ORGANS
THE organs forming the urinary apparatus [organa uropoetica] are the kidneys, by which the secretion is produced; a duct, the ureter, proceeding from each kidney and convejdng the secretion to the bladder, which serves as a reservoir for the urine and from which, by a single duct, the urethra, the secretion is carried to the exterior.
THE KIDNEYS
The kidneys [renes] are paired organs situated in the abdominal region and each is composed of a very great number of minute tubules, the renal tubules, enclosed within a definite and firm fibrous capsule. Each kidney is somewhat bean-shaped (fig. 1004) and is situated on the dorsal wall of the body, behind the parietal peritoneum, in such a way that the ventral or visceral surface [facies anterior] which is convex, looks obhquely ventrally and laterally, while the dorsal or parietal surface [facies posterior], usually less convex, looks dorsally and somewhat medially (fig. 1005). The upper extremity {extremitas superior] is usually larger
UROGENITAL SYSTEM
than the lower [extremitas inferior] and is about 1 cm. nearer the median sagittal plane of the body, owing to the long axis of the organ being directed obliquely downward and laterally. The lateral border [margo lateralis] is narrow and convex, and the medial border [margo medialis], which looks medially and ventrally, is concave, its middle third presenting a slit-hke aperture, the hilus. This opens into a cavity, called the sinus (fig. 1006), which is about 2.5 cm. in depth and is occupied mainly by the dilated upper extremity of the ureter, known as the renal pelvis, the interval between this and the actual kidney substance containing adipose tissue in which are imbedded the renal vessels and nerves.
Size. — The length of the kidney in the male averages 10-12 cm., its breadth about 5.5 cm. and its thickness 3 cm.; it weighs 115-150 grams. The dimensions of the female kidney are nearly as great, but its weight is from one-seventh to one-fifth less. In the child the organ is relatively large, its weight compared with that of the entire body being about 1 : 133 at birth; but its permanent relation, which is about 1:217, is usually attained at the end of the tenth year.
Investment and fixation. — The surface of the kidney is covered by a thin but strong ^??roMs capsule [tunica fibrosa], which turns inward at the hilus to line the walls of the sinus (fig. 1006). It may readily be peeled off from a healthy kidney, except at the bottom of the sinus, where it is adherent to the blood-vessels entering the kidney substance and to the terminal portions of the pelvis. External to the capsule is a quantity of fat tissue, the adipose capsule [capsula adiposa], which forms a complete investment for the organ and is prolonged through the hilus into the sinus.
The peritoneum, which covers the ventral surface of the adipose capsule, has usually been regarded as the principal means of fixation of the kidney, but in reality this is accompHshed by means of a special renal fascia (fig. 1005), developed from the subperitoneal areolar tissue (Gerota).
Renal fascia. — Lateral to the kidney there occurs between the transversalis fascia and the peritoneum a subperitoneal fascia, which, as it approaches the convex border of the kidney, divides into two layers, one of which passes in front of and the other behind the kidney, enclosing the adipose capsule. Traced medially, the anterior layer of the renal fascia passes in front
of the renal vessels, and, over the aorta, becomes continuous with the corresponding layer of the opposite side; upward, it passes over the suprarenal gland and at the upper border of that organ becomes continuous with the posterior layer; and downward, it is lost in the adipose tissue intervening between the iliac fascia and muscle. The posterior layer, which is the thicker of the two, passes medially behind the renal vessels and is lost in the connective tissue in front of the vertebral column, and below it is lost, like the anterior layer, in the ihac region. Behind the posterior layer, between it and the quadratus lumborum, is a mass of adipose tissue, the pararenal adipose body, and both layers are united to the fibrous capsule of the kidney by trabeculae of connective tissue which transverse the adipose capsule.
Each kidney is, accordingly, supported by these trabecute in a space bounded laterally and above by the layers of the renal fascia, and open medially and below. Should these trabeculse become atrophied by wasting disease or ruptured by the pressure of the pregnant uterus, by the improper use of corsets, or by any other cause, the phenomenon of movable or wandering kidney may be set up by slight external violence, the organ tending to shift its place as far as the attachment of its vessels to the main trunks and the arrangement of the renal fascia will permit.
Position and relations. — The kidney is said to lie in the lumbar region. It is, however, intersected by the horizontal and vertical planes which separate the hypochondriac, lumbar, epigastric and umbilical regions from each other, and hence belongs to all these segments of the abdominal space. Its vertical level may be said to correspond to the last thoracic and upper two or three lumbar
The posterior surface (figs. 1007, 1008), with the corresponding portion of the fatty capsule and the pararenal adipose body, rests against the posterior abdominal wall extending upward in front of the eleventh and twelfth ribs, and medialward to overlap the tips of the transverse processes of the first and second lumbar vertebrae; the left kidney usually reaches as high as the upper border of the eleventh rib, the right only to its lower border. The only visceral relation posteriorly is on the left side, where the spleen slightly overlaps the kidney opposite the upper half of its lateral border, the adjacent surfaces of the two organs loeing, however, covered by peritoneum. The parietal relations (fig. 1008) on both sides are as follows: (1) the diaphragm, the left kidney, on account of its higher position, entering more extensively into this relation than the right ; (2) the portion of the transversalis fascia covering the ventral surface of the quadratus lumborum; (3) the lateral border of the psoas; and (4) the last thoracic, ilio-
The upper extremity of each kidney is crowned by the suprarenal gland (figs. 1007, 1009), which encroaches also upon its ventral surface and medial border and is fixed to it by fibres derived from the subperitoneal tissue.
The anterior surface of each kidney was primarily completely covered by peritoneum that separated it from neighboring viscera, but, owing to secondary changes whereby the ascending and descending colons, the duodenum and the pancreas become retro-peritoneal organs, these come into direct relation with one or the other of the kidneys and separate portions of them from actual contact with the peritoneum. Thus, in the case of the right kidney (fig. 1009), the
mpulla of rectum
portion of the anterior surface immediately adjacent to the medial border has the descending portion of the duodenum in direct contact with it, and throughout a zone extending downward and laterally from the middle of the duodenal area to the lateral border the ascending colon and right colic flexure. Almost the entire upper half, however, and a small portion of the lower pole are covered directly by peritoneum, the upper peritoneal area having an indirect relation with the lower surface of the liver, upon which it produces the renal impression.
Similarly the anterior surface of the left kidney (fig. 1009) is in direct contact with the pancreas throughout a broad transverse band situated a little above the middle of the organ, and the splenic artery pursues its tortuous course along the upper border of this pancreatic area, while the corresponding vein is interposed between the pancreas and the surface of the kidney. The lateral portion of the lower extremity is in direct contact with the descending colon and its splenic
flexure, but the remainder of the lower extremity and the whole of the upper onefourth of the organ is directly covered by peritoneum, the upper peritoneal area having, as an indirect relation, the posterior surface of the stomach medially, and the spleen laterally (figs. 956, 1009).
Variation in position. — The position of the kidneys in the abdominal cavity is subject to considerable variation. Thus while the upper pole of the right kidney may be said to lie typically opposite the lower half of the eleventh thoracic vertebra, it may be placed as high as the lower part of the tenth thoracic or as low as the upper half of the fii'st lumbar. Similarly while the upper pole of the left kidney is as a rule opposite the middle of the eleventh thoracic vertebra it may lie half a vertebra higher or as low as the lower part of the second lumbar vertebra. The lower poles are distant from the crests of the ilia anywhere from 1.0 cm.-3.0
lower pole may even extend below the iliac crest, especially on the right side.
The lateral border of each kidney lies 8.5-10.0 cm. lateral to the spines of the lumbar vertebrae, a distance that brings them lateral to the lateral edge of the sacro-spinahs muscle and even to the lateral edge of the quadratus lumborum, so that this border may be readily approached through the posterior wall of the body. It must be remembered, however, that the upper part of the kidney rests upon the diaphragm, so that in the event of the twelfth rib being very short there may be danger of the incision being carried too far upward, resulting in injury to the diaphragm and pleura. It is also worthy of note that the diaphragmatic. area of
the kidney corresponds with the region where a hiatus diaphragmaticus between the costal and lumbar portions of the muscle may occur and if this be pronounced the upper part of the posterior surface of the kidney may come into more or less direct relations to the pleura (fig. 1008).
Just as there may be variation in the position of the kidneys, so too there may be considerable variation in the extent to which they are in relation to the various structures mentioned above. And this is especially true as regards their relations to the colons; for if the kidneys were lower than usual they might lie entirely beneath the line of attachment of the transverse mesocolon and thus have no direct relations with either colon, or on the other hand either the ascending or descending colon, or both, may be provided with a mesentery, whereby they would be removed from direct contact with the kidney.
Structure. — A section through the kidney shows its substance to be composed of an external or cortical [substantia corticalis] and an internal or medullary portion [substantia medullaris] (fig. 1010). The medulla consists of a variable number (eight to eighteen) of conical segments termed renal pyramids [pyramides renales (Malpighii)], the apices of which project into the bottom of the sinus (fig. 1006) and are received into the primary segments (calyces) of the pelvis, while their bases are turned toward the surface, but are separated from it and from each other by the cortex. The pyramids are smooth and somewhat glistening in section and are marked with delicate striae which converge from the base to the apex and indicate the course of the renal tubules. The blunted apex, or papilla, of each pyramid, either singly or blended with one or even two of its fellows, is embraced by a calyx (fig. 1006), and, if examined with a hand-lens, will be seen to present a variable number (twelve to eighty) of minute apertures, the foramina papillaria, which represent the terminations of as many papillary ducts (of Bellini) through which the secretion escapes into the pelvis.
The cortex may be regarded as composed of two portions, (1) a peripheral layer, the cortex proper, which is about 12 mm. in thickness and extends from the fibrous capsule to the bases of the pyramids, and (2) processes termed renal columns [columnse renales (Bertini)] which dip inward between the pyramids to reach the bottom of the sinus (fig. 1010). In section the cortex is somewhat granular in aspect, and when examined closely shows a differentiation into a number of imperfectly separated portions termed cortical lobules [lobuli oorticales]. Each of these is composed of a convoluted portion [pars convoluta], surrounding an axial radiate portion (pyramid of Ferrein) [pars radiata (processus Ferreini)]. The latter consists of a group of tubules which extend from the cortex into the base of one of the medullary pyramids, whence it is also termed a medullary ray; and each medullary pyramid is formed from the rays of a number of cortical lobules, these structures, therefore, greatly exceeding the pyramids in number.
Renal tubules (fig. 1011). — The structure described above is the result of the arrangement of the renal tubules, which constitute the essential units of the kidney. Each of these commences in a spherical glomerular capsule (fig. 1011), one wall of which is invaginated by a small glomerulus of blood-vessels, the combination of glomerulus and capsule forming what is termed a renal (Malpighian) corpuscle. These corpuscles are situated in the convoluted portions of the cortical lobules, and from each of them there arises by a narrow neck a tubule, which quickly becomes wide and convoluted, this fiortion being termed the first convoluted tubule. This enters a medullary ray, where it narrows again and descends as a straight tubule, the descending limb of Henle's loop, into the subjacent medullary pyramid, and, turning upon itself, forming the loop of Henle, ascends to the cortex, where it again becomes wide and contorted, forming the second convoluted tubule. This again lies in the convoluted portion of the cortical lobule, and, becoming narrower, opens with other similar tubules into a straight or collecting
at the summit of a papilla.
The tubules are hned with epithelium throughout, the cells being tesselated in the capsule, irregularly cubical in the convoluted tubules and ascending limbs, flattened on the descending limbs and loops of Henle, and columnar in the cortical collecting tubules and in the straight tubules of the medulla.
Vessels (fig. 1011). — The kidney is very vascular. The larger arterial branches, arranged in the sinus as has already been described, enter the substance of the kidney and pass up as the interlobar arteries in the renal columns. On reaching the bases of the pyramids they bend so as to run horizontaUy between these and the cortex, forming the arcuate arteries [arterife arciformes] from which interlobular branches pass up into the cortex and supply afferent branches to the Malpighian glomeruh. From the arcuate arteries numerous branches, the arterioloe rectces,
papillare
pass down into the pyramids, supplying the tubules of which these are composed. Efferent stems which issue from the Malpighian glomeruli break up into capillaries which supply the tubules contained in the cortex. Veins corresponding to the arteriolse rectce and to the interlobular, arcuate and interlobar arteries occur, opening into the renal veins, and, at the surface of the kidney, arranged in star-like groups, are the stellate veins [vense steUatae], which open into the interlobular veins and also communicate with the veins of the adipose capsule. The renal lymphatics may be divided into two sets, capsular and parenchymatous. They terminate in the upper lumbar nodes.
is capped by a thin layer of cortex. Such a condition is permanent in some of the lower animals; but in man the superficial indications of morphological segmentation usually become obliterated during the progress of growth of the cortical tissue, and are seldom visible after the age of ten.
Development. — In the development of the embryo, representatives of three different sets of excretory organs occur, the permanent kidney (metanephros) being the last to form. The two earlier sets (pronephros and mesonephros) have a common duct, the Wolffian duct, and from the lower end of this an outgrowth develops, which extends upward on the posterior abdominal wall and comes into connection with a mass of embryonic tissue known as the metanephric blastema. The outgrowth gives rise to the ureter, pelvis and collecting tubules, while the remaining portions of the tubules are formed from the blastema.
Various abnormalities may result from modifications of the development of the kidneys. (1) Occasionally the ureteric outgrowth of one side fails to develop, the result being the occurrence of a single kidney. (2) The blastema may fail to attain its normal position, in which case the kidney may be situated in the iliac region or even in the pelvis; or the blastema may be drawn into an unusual position, the kidney resting on the vertebral column, or even on the opposite side of the abdomen; (3) or the two blastemas may fuse to a greater or less extent, forming a "horse-shoe kidney," extending across the vertebral column; or, if the fusion be more extensive, an apparently single kidney, which may rest upon the vertebral column, or to one side of it. Such fused kidneys may be distinguished from single kidneys by the fact that they possess two ureters opening normally into the bladder. (4) In rare cases, a blastema may become divided, an accessory kidney of varying size being thus produced. (5) Finally, in one or more of the tubules there may be a failure of the union of the portion derived from the blastema with the collecting tubule derived from the ureteric upgrowth, and the secretion having no means of escape from such malformed tubules, they become greatly dilated, producing a cystic kidney.
The ureter (figs. 1004, 1007, 1012, 1015), which serves as the excretory duct of the kidney, is a canal, expanded and irregularly branched above, but narrow and of fairly uniform dimensions throughout the rest of its course. At its origin in the renal sinus it consists of a number of short tubes, usually eight or nine, called calyces minores (fig. 1012), each of which embraces a renal papilla, or occasionally two papillae may be connected with a single calyx. These calyces minores open directly or by means of short intermediate tubes (infundibula) into two short passages, the superior and inferior calyces majores, which in turn unite after a longer or shorter course to form the pelvis. Occasionally a third or middle calyx major is present.
The pelvis [pelvis renalis] (fig. 1012) is usually more or less funnel-shaped, being wider above, where it lies between the two lips of the hilus, and narrower below, where it arches downward and medially to become continuous with the ureter proper. It is, however, very variable in shape and in some cases is hardly larger than the ureter. Usually it is flattened dorso-ventrally so that its anterior and posterior walls are in contact and its cavity represented merely by a fissure. The majority of the branches of the renal vein and artery lie in front of it, imbedded in fat tissue, and anterior to these are the descending portion of the duodenum on the right side and the pancreas on the left. The intra-renal portions of the ducts, including the pelvis, are considered parts of the kidney.
The ureter proper (fig. 1007) extends from the termination of the pelvis to the bladder, its course lying in the subperitoneal tissue. It is a tube about 5 mm. in diameter when distended and it is fairly uniform in size, except that a slight constriction occurs where it enters the pelvis and a second one occurs at about the middle of its abdominal portion. Its length is variously stated, but the average in the male adult may be taken as about 30 cm., the right being usually a little the shorter.
Course and relations. — The course of each ureter may be conveniently divided into three portions, abdominal, pelvic, and vesical. The abdominal portion [pars abdominalis] runs downward and shghtly medially and is in relation posteriorly with the psoas muscle and its fascia; it crosses the genito-femoral nerve obhquely and in the lower part of its course passes in front of the common iliac artery near its bifurcation. Anteriorly it is covered by peritoneum and is crossed by the spermatic or ovarian vessels. Medially it is in relation on the right side with the inferior vena cava and on the left with the aorta, the vein being almost in contact with the right ureter, while the artery is separated from the left one by an interval that diminishes from 2.5 cm. above, to 1.5 cm. opposite the bifurcation of the vessel.
THE URINARY BLADDER 1249
and then forward and downward upon the obturator internus and its fascia behind and below the psoas, crossing the obturator vessels and nerve and having anterior to it in the female the posterior border of the ovary. It thus reaches the level of the floor of the peritoneal cavity, whereupon, at about the level of the ischial spine, its course is directed forward and medially toward the bladder. In this part of its course in the m.ale, it is crossed superiorly and medially by the ductus deferens, and then passes under cover of the free extremity of the vesicula seminalis, separated from its fellow by a distance of 37 mm. In the female it runs parallel with, and 8 to 12 mm. distant from, the cervix uteri, passes behind the uterine artery, through the uterine plexus of veins, and beneath the root of the broad ligament, and finally crosses the upper third of the lateral wall of the vagina to reach the vesico-vaginal interspace and enter the substance of the bladder at about the junction of its posterior, superior and lateral surfaces.
The vesical portion, about 12 mm. in length, runs obliquely downward and medialward through the coats of the bladder, and opens on its mucous surface about 20 to 25 mm. from both its fellow and the internal urethral orifice.
Structure. — The wall of the ureter is about 1 mm. (jV in.) in thickness, and consists of a mucous membrane, a muscular coat, and an external connective-tissue investment. The mucous membrane is longitudinally plicated, and is lined by transitional epithelium, continuous with that of the papillse above and with that of the bladder below. Mucous follicles of simple form have been found in the upper part of the canal. The muscularis is about 0.5 mm. (1/50 in.) in thickness, and consists of two layers, an external, composed of annular fibres, and an internal,
Inferior calyx major
of fibres longitudinally disposed. After the tube has entered the bladder the circular fibres form a kind of sphincter around its vesical orifice; while the longitudinal fibres are continued onward through the wall of the bladder and terminate beneath its mucous membrane.
Vessels and nerves. — The arteries supplying the pelvis and upper part of the ureter come from the renal; the rest of the abdominal portion of the ureter is supplied by the spermatic (or ovarian), and its pelvic portion receives branches from the middle haemorrhoidal and inferior vesical; the veins terminate in the corresponding trunks; and the lymphatics pass to the lumbar and hypogastric nodes. The nerves are supplied by the spermatic, renal, and hypogastric plexuses.
Variations. — Occasionally the depression which separates the two calyces majores extends through the pelvis, so that the calyces appear to open directly into the ureter. The fission may also affect the ureter to a greater or less extent, in extreme cases producing a duplication of the tube throughout its entire length.
The urinary bladder [vesica urinaria] is a receptacle, whose form, size, and position vary with the amount of its contents. The adult organ in its empty or moderately filled condition Hes entirely below the level of the obhque plane of the pelvic inlet; but when considerably distended it rises into the abdomen and shows itself beneath the parietes as a characteristic mesial projection above the symphysis, a projection which in extreme distention of the bladder may extend nearly to the level of the umbilicus.
Form. — When distended it assumes in the male an ovoid shape with its longest diameter directed from above downward and backward; but in the female the transverse diameter is the greatest, in accordance with the greater breadth of the pelvic cavity. In the child it is somewhat pear-shaped, the stalk being represented by the urachus.
Parts. — ^For convenience in description five surfaces may be recognized, but they are but indistinctly separated from each other. One, the anterior or pubic surface, is directed forward and downward; second, the superior or intestinal surface, looks upward; the third, the posterior surface, looks backward; and the other two are the lateral surfaces. The anterior, superior, and lateral surfaces meet at the vertex of the bladder, from which the middle umbilical ligament (urachus) extends to the umbilicus; the posterior surface, sometimes flat and sometimes, especially in old age, convex, forms what is known as the base or fundus [fundus vesicae] ; and the portion of the viscus intervening between the vertex and
fundus is termed the body [corpus vesicae]. In the centre of the line between the anterior and posterior surfaces is the internal urethral orifice [orificium urethrae internum], by which the bladder communicates with the urethra, and the portion of the organ immediately surrounding this is sometimes spoken of as the neck.
When the bladder is empty and relaxed, the superior surface sinks down upon the anterior and posterior surfaces, thus becoming concave, and the cavity of the organ is reduced to a T- or Y-shaped fissure. In the female, the cavity of the empty bladder in mid-sagittal section often more nearly resembles a figure 7 (see fig. 1014).
Relations. — The anterior surface looks downward and forward toward the symphysis pubis (figs. 1013, 1014). It is uncovered by peritoneum, but is separated from the pubic bones and anterior attachments of the obturatores interni and the levatores ani by a space known as the prevesical space (cavum Retzii),
which contains a variable quantity of loose fat continuous with the pelvic and abdominal subperitoneal tissue. Each lateral surface is covered by peritoneum down to the level at which it is crossed obliquely from behind forward and upward by the obUterated hypogastric artery. Below this level it is separated from the levator ani and obturator internus by subperitoneal tissue, which usually bears much fat in its meshes and ensheaths the vesical vessels and nerves. It is also crossed by the ductus deferens, which passes between the ureter and the wall of the bladder, a little above the level at which the former enters the wall of the bladder, at the junction of its lateral and posterior surfaces and about 3.5'^cm. above the fundus. The posterior surface may be divided into two portions, an upper covered by the peritoneum of the recto-vesical or vesico-uterine pouch (fig. 1013), and a lower in direct contact in the male with the anterior wall of the
rectum and with the lower part of the ductus deferentes and the vesiculse seminales. Between the diverging ductus deferentes there is a triangular space, whose base is formed by the line of reflexion of the recto-vesical pouch of peritoneum and the apex by the meeting of the ejaculatory ducts at the summit of the prostate. It represents the area of direct contact of the posterior wall of the bladder withjthe rectum. In the female the posterior surface is adherent in its lower part to the cervix of the uterus and the upper part of the anterior wall of the vagina (fig. 1014), but it is separated above from the body of the uterus by the shallow vesicouterine pouch of peritoneum.
small intestines and sometimes a portion of the sigmoid colon behind these.
Variation in position. — In the normal condition the bladder of the adult lies below the upper border of the symphysis pubis, but if fully distended it may rise above this level, carrying with it the reflexion of peritoneum from its upper surface to the anterior abdominal wall. The anterior surface of the bladder is thus brought into relation with the anterior abdominal wall, being separated from it only by the enlarged prevesical space, and it is thus possible to enter the bladder above the symphysis pubis without penetrating the peritoneum.
In the infant, owing to the smaller extent of the pelvic cavity, the bladder hes at a somewhat higher level than in the adult and rises into the abdominal cavity. Indeed the entire bladder is above the horizontal level of the pubic crests, the urethral orifice being behind the upper margin of the symphysis pubis. As the child learns to walk, however, this position gradually alters and usually by the age of six years the adult relations have been acquired.
The fixation of the bladder. — The reflections of the peritoneum from the superior surface of the bladder to the anterior abdominal wall and from the sides and back to the corresponding walls of the pelvis are sometimes described as the superior, lateral and posterior false ligaments. Furthermore there extends from the apex of the bladder to the umbilicus a fibrous cord, the urachus, the remains of the embryonic allantois; this is described as the middle umbilical ligament of the bladder (fig. 1014), and lateral umbilical ligaments are formed by the obliterated hypogastric arteries which carried the foetal blood to the placenta and in the
ascending to the umbilicus.
In addition to these structures certain thickenings of the endopelvic fascia, where it comes into relation with the base of the bladder and prostate gland, constitute what are termed the true ligaments. Two such thickenings extend from the anterior surface of the capsule of the prostate gland, or from the lower part of the anterior surface of the bladder in the female, to the pubic bones and constitute what are known as the middle pubo-prostatic {pubo-vesical) ligaments, with which muscle fibres [m. pubovesicahs] are usually associated. Similarly, thickenings of the fascia extending from the sides of the prostate gland or from the sides of the base of the bladder to the lateral walls of the pelvis form the lateral true ligaments.
Muscle fibres [m. rectovesicahs] also occur in the subperitoneal tissue contained within the peritoneal folds (posterior false ligaments) extending from the back of the bladder to the posterior wall of the pelvis and bounding the recto-vesical pouch of peritoneum in the male. They correspond to the mm. redouterini of the female.
The internal surface. — The mucous membrane lining the internal surface of the bladder is soft and rose-coloured during life, and in the empty bladder is thrown into irregular folds which become effaced by distention. It is modified over a triangular area at the base of the bladder, termed the trigone [trigonum vesicae (Lieutaudi)] (fig. 1015) whose three angles correspond with the orifices of the urethra and of the two ureters, and are separated from one another by a
MALE REPRODUCTIVE ORGANS 1253
distance of 20 to 25 mm. This area is paler in colour and free from the plication that characterizes the rest of the mucous membrane; it is bounded posteriorly by a transv.erse ridge, the plica ureterica, extending between the orifices of the ureters, and toward the urethral orifice presents a median longitudinal elevation, the uvula vesicae, which is apt to be especially prominent in aged persons. The internal urethral orifice is normally situated at the lowest point of the bladder, at the junction of the anterior and posterior surfaces. It is surrounded by a more or less distinct circular elevation, the urethral annulus, and is usually on a level with about the center of the symphysis pubis and from 2.0 to 2.5 cm. behind it.
Structure. — The general characteristics of the mucous membrane of the bladder, which is lined by epithelium of the transitional variety, have already been described. It rests upon a loose submucous tissue, which contains numerous elastic fibres. The greater part of the thickness of the waU is formed, however, of the muscular coal, consisting of non-striped muscle tissue, the fibres of which are arranged in three more or less distinct layers. The outer layer is composed mainly of longitudinal fibres, some of which are continued forward to the pubis from the neck of the bladder to form the mm. pubovesioales and others backward to form the mm. rectovesicales. To this outer layer the term m. detrusor uriruB has been applied, but it should be noted that it does not contract independently of the circular layer. The middle ayer is thicker than the outer and more uniformly developed. It consists of fibres having for the most part a circular direction and is well developed over all the upper portion of the bladder, but becomes thinner in the region corresponding to the trigone. It is here that the inner layer is chiefly developed, consisting of fibres, which are situated partly in the submucous tissue and have a general longitudinal direction throughout the region of the trigone. At the neck of the bladder, however, they form a strong circular bundle, which is continued into the prostatic portion of the urethra and forms what is termed the internal sphincter of the bladder.
Vessels. — The arteries of the bladder are usually two in number, the superior and inferior vesical, branches of the hypogastric artery; the fundus also receives branches from the middle hsemorrhoidal and in the female twigs are also sent to it from the uterine and vaginal arteries. The veins form an extensive plexus at the sides of the bladder, from which stems pass to the hypogastric trunk. The lymphatics accompany the veins and communicate with the hypogastric nodes, some of those from the fundus passing to nodes situated at the promontory of the sacrum.
Nerves. — -The nerves are derived partly from the hypogastric sympathetic plexus and partly from the second and third sacral nerves. The fibres from the latter constitute the nervi erigentes, stimulation of which produces contraction of the general musculature and rela.xation of the internal sphincter. On each side of the bladder there is formed a sympathetic vesical plexus, from which superior and inferior vesical nerves pass to the corresponding parts of the bladder.
Development. — In the earlier stages of development the urogenital ducts and the digestive tract open below into a common cavity, the cloaca, from the ventral portion of which a long tubular outgrowth, the allantois, extends out to the placenta through the umbilical cord. Later the cloaca becomes divided in the frontal plane into a ventral portion which receives the urogenital ducts, and a dorsal portion, which becomes the lower end of the rectum. From the upper part of the ventral portion the bladder is developed. Since the cloaca is fined by endoderm the mucous membrane of the bladder is mainly derived from that embryonic layer, but it is worthy of note that portions of the lower ends of the ureters are taken up into the wall of the bladder, giving rise to the area of the trigone, whose mucous membrane is thus of mesodermal origin. The portion of the allantois within the body of the foetus is transformed after birth into a fibrous cord, the urachus.
The reproductive organs of the male consist of (1) two testes in which the spermatozoa are formed, (2) their ducts, the ductus def erentes ; enclosed throughout a portion of their course in the spermatic cord; and the seminal vesicles, reservoirs for the semen, connected with the ductus def erentes; (3) the penis, the organ of copulation, which is traversed by the urethra; (4) the urethra, a canal into which the ductus deferentes open and which also gives exit to the contents of the bladder; (5) the prostate gland, a musculoglandular structure surrounding the beginning of the urethra; (6) the bulbo-urethral glands which open into the urethra.
1. The Testes and Their Appendages
The scrotum. — The two testes, together with the beginning of the ductus deferentes, are contained within a pouch, the scrotum, which is divided into two compartments by a median sagittal septum, the edge of which is indicated on the surface by a ridge-hke thickening of the integument, termed the raphe.
This double condition of the scrotum is explained by its origin from the fusion of two outpouchings of the lower portion of the abdominal wall, the inguinal canals forming, as it were, the necks of the outpouchings. The testes are primarily retroperitoneal abdominal organs, but later they descend through the inguinal canals into the scrotal outpouchings, where they lie between the peritoneal sac which each of these contains and the remaining layers of the wall, thus retaining their retroperitoneal position. The peritoneal sacs are at first in communication with the abdominal cavity, but after the descent of the testes each undergoes degeneration in its upper part, the cavity disappearing and the peritoneal tissue becoming converted into a portion of the connective tissue in which the ductus deferens and the vessels and nerves associated with it are imbedded in their course through the spermatic cord. The portion of the sac in relation with each testis persists, however, and wrapping itself around that structure forms for it a serous investment, the tunica vaginalis propria (fig. 1016).
The integument oi the scrotum is more or less pigmented and presents numerous transverse ridges extending laterally on either side from the raphe. It is furnished in the adult with coarse, scattered hairs and its sebaceous and sudoriparous glands are well developed. The deeper layers of the dermis, have a pinkish colour, and form what is termed the dartos (fig. 1016), the colouration being due to the
Epididymis
presence in it of numerous non-striated muscle fibres, which are for the most part arranged at right angles to the wrinkles of the surface and are the cause of these. The more superficial fibres of the dartos, hke the rest of the integument, form a common investment for both testes, but the deeper ones of either side bend inward at the raphe and assist in the formation of the septum.
Internal to the dartos and closely related to it is a layer of laminated connective tissue, the cremasteric fascia. It is destitute of fat and is continuous at the subcutaneous inguinal ring with the intercrural fibres, being probably the scrotal representative of the external oblique muscle. It is succeeded by a strong sheet of fascia containing longitudinal bands of striated muscle tissue, forming what is termed the cremaster muscle (figs. 389, 1016) and being continuous above with the fibres of the internal oblique muscle of the abdomen. Internal to this is a thin layer of connective tissue, the tunica vaginalis communis, which is continuous with the transversalis fascia at the inguinal ring, and, finally, there is the tunica vaginalis propria, which forms the serous investment of the testis and, as has been stated, is of peritoneal origin. Like other similar serous investments it has the form of a double sac, the outer or parietal layer of which is closely adherent to the tunica vaginahs communis and contains numerous nonstriped muscle fibres forming what has been termed the internal cremaster muscle. The inner or visceral layer is thinner and closely invests the testis and a
THE TESTIS AND EPIDIDYMIS
portion of the epididymis, being reflected from the inferior and posterior parts of the latter to be continuous with the parietal layer. Toward the upper part of the lateral surface of the testis it is folded in between that structure and the epididymis, forming a well-marked pocket, the sinus eipididymidis (digital fossa) (fig. 1017), whose upper and lower lips form what are termed the ligamentaepididymidis.
Vessels and nerves. — The skin and dartos of the scrotum are supplied partly by the perineal branch of the internal pudendal artery and partly by the external pudendal branches of the femoral. The deeper layers are supplied by the spermatic branch of the inferior epigastric. The veins accompany the arteries, the external pudendals opening into the internal saphenous vein near its termination. The lymphatics terminate in the more medial inguinal nodes. Several nerves take part in the supply of the scrotum. The external spermatic branch of the genito-femoral gives sensory branches to the anterior and lateral surfaces and also supplies the external cremaster muscle; the posterior surface is supplied by the periaeal branch of the pudendal nerve; and the inferior surface by the perineal branches of the posterior femoral
cutaneous. The anterior aspect of the scrotum is also supplied by anterior scrotal branches of the ilio-inguinal. The non-striped musculature is probably supplied by the internal spermatic nerve from the hypogastric plexus.
Hernia. — The communication of the tunica vaginaUs propria vrith the abdominal peritoneum is usually obliterated within a few days after birth, but sometimes the process of obliteration is more or less incomplete. If the communication remains open there is a free passage for a loop of the intestine to enter the cavity of the tunica vaginalis, such a condition constituting what is known as the congenital variety of inguinal hernia. If the communication be interrupted only at the upper part of the original sac, so that the cavity of the tunica vaginalis propria extends a considerable distance up the spermatic cord a hernia, passing through the inguinal canal, may invaginate the upper part of the tunica vaginalis into the lower, producing what is termed the encysted variety of hernia. Or if, finally, the obliteration of the communication begins in the neighbourhood of the testis, a funnel-shaped prolongation of the peritoneal cavity may extend downward into the spermatic cord, and hernia into this constitutes the variety known as hernia i^ito the funicular process.
each being of a flattened oval form, with two surfaces, medial and lateral, two borders, anterior and posterior, and two extremities, superior and inferior. To the whole of the posterior border there is attached the epididymis, formed by the efferent ducts. The testis is obliquely placed, so that the medial surface also looks somewhat forward and downward.
The surface of the testis is covered by the visceral layer of the tunica vaginalis propria except where it is in contact with the epididymis, and is formed by a dense white inelastic capsule, the tunica albuginea, beneath which is a looser and more vascular layer known as the tunica vascidosa. From the inner surface of the albuginea, lamellae of connective tissue, known as septula, converge toward the posterior border of the testis and toward its upper part unite together to form a network (fig. 1018), the mediastinum testis (or corpus Highmori), through which blood-vessels and lymphatics enter and leave the testis, while by the interspaces of the network, known as the rete testis, the tubules of the testis are placed in communication with the epididymis.
The septula divide the substance of the testis into a number of compartments or lohules, each of which is occupied by a number of slender, greatly contorted canals, the seminiferous tubules [tubuli seminiferi], from whose epithelial lining the spermatozoa are formed. The tubules of each lobule converge to form a single, almost straight duct and these tubuli recti pass
Ductus deferens
toward the mediastinum, where they open into the rete testis. In the lobules the seminiferous tubules are imbedded in a loose connective tissue that contains certain pecuhar cells, the interstitial cells, to which has been attributed the formation of an internal secretion.
The epididymis (fig. 1017), which lies along the posterior border of the testis, is an elongated structure with a body [corpus epididymidis], enlarged above to form the head [caput] and to a less extent below to form the tail [cauda]. It is invested by a tunica albuginea, continuous with, but much thinner than that of the testis, and is formed mainly by the greatly contorted duct of the epididymis, which represents the beginning of the ductus deferens.
The head is formed by 12-14 tubules, the efferent ducts (fig. 1018), which take their origin from the rete testis as almost straight tubules, but gradually become greatly coiled, so that each duct has the form of an elongated cone, its coiled portion forming what is termed a lobulus epididymidis. At their coiled ends the various efferent ducts open into a single tube, the ductus epididymidis. Its diameter is only about 0.4 mm., but it measures 6.0-7.0 metres (18-21 feet) in its entire length, being coiled so extensively as to be contained within the body and tail of the epididymis. In this latter region it passes over into the ductus deferens.
Vessels. — The principal artery supplying the testis is the internal spermatic, from which branches are also sent to the epididymis. The deferential artery, a branch of the superior vesical, also sends branches to the epididymis and enters into extensive anastomoses with the testicular branches of the internal spermatic, and anastomoses also occur with the vessels supplying the scrotum. The veins correspond with the arteries. The lymphatics of the testis and epididymis unite to form four to six large stems which pass upward in the spermatic cord to terminate in the lower lumbar nodes.
DUCTUS DEFERENS AND SEMINAL VESICLE 1257
and some of whose tubules, becoming the efferent ducts, place the seminiferous tubules in comnaunioation with the ductus deferens. The epididymis may therefore be said to be developed from the mesonephros. The portions of this structure that are not concerned in the formation of the efferent ducts disappear for the most part; a few of the tubules persist, however, as rudimentary organs associated with the epididymis. Among these may be mentioned one or more blindly ending, coiled tubules, varying from 5-30 cm. in length, which are connected with the ductus epididymidis usually in the tail of the epididymis. They are knowTi as the ducluli aberrantes (fig. 1018) and may be regarded as persistent excretory mesonephric tubules. Another of the rudimentary organs is the paradidymis {organ of Giraldes), which is a whitish body, situated immediately above the head of the epididymis, and is composed of irregularly coiled tubules, which terminate blindly at both extremities. They may be regarded as efferent ducts that have failed to connect with the testis and are of interest in that they sometimes develop into cysts connected with the epididymis.
In addition there is frequently attached to the upper pole of the testis a sohd oval body composed of connective tissue, known as the appendix testis {hydatid of Morgagni) (fig. 1017). It measures from 3 to 8 mm. in length and its significance is doubtful. A similar, though smaller structure, the appendix epididymidis, is attached less frequently to the head of the epididymis. It is usually provided with a distinct stalk and contains a cavity; it is believed to represent the upper end of the Miillerian duct, present in the embryo and giving rise to the tuba uterina in the female, but almost completely degenerating in the male.
The testis begins its descent from the abdominal cavity into the scrotum at the third month of fetal life and reaches the abdominal inguinal ring at about the sixth month, but it is not until shortly before birth that it arrives at its final location in the scrotum. The cause of the descent is stiU uncertain, but it is supposed to be partly due to the failure of a band of connective tissue, which extends from the lower pole of the embryonic testis to the bottom of the scrotal pouch, to keep pace with the growth of the body walls. This hgament, which is known as the gubernac.ulum testis, thus becomes relatively shorter and draws the testis downward toward the point of its attachment to the scrotum. There are various features in the descent, however, that cannot be explained by the simple traction of the gubernaculum and it must be regarded as a complicated growth process whose meaning is yet uncertain. The gubernaculum testis apparently undergoes degeneration after the testis has reached its definitive location and cannot be recognized in connection with the adult testis.
Occasionally the descent of the testis is interrupted, the organ remaining either in the abdomen or in the inguinal canal. This condition of cryptorchism is always associated with a suppression of the function of the organ.
Each ductus deferens is the continuation of a ductus epididymidis and extends from the tail of the epididymis to the prostatic portion of the urethra. At its beginning it ascends along the posterior border of the epididymis (testicular portion) and is at first slender and tortuous (fig. 1018), but before reaching the level of the head of the epididymis it becomes straighter and thicker (fig. 1017), owing to the development in its walls of strong layers of longitudinal and circular non-striated muscle tissue. Thence it is continued almost vertically upward as one of the constituents of the spermatic cord {funicular portion) to the subcutaneous inguinal ring, and, entering this, traverses the inguinal canal {inguinal portion), still forming a portion of the cord. At the abdominal ring it separates from the other constituents of the cord and, looping over the inferior epigastric artery near its origin, passes downward and backward over the lateral surface of the bladder {pelvic portion). At the junction of the posterior and lateral surfaces of the bladder it passes medially to the ureter and is then continued downward, forward and medially upon the base of the bladder until it reaches the prostate gland (fig. 1019), whose substance it traverses, as the ductus ejaculatorius, to open into the prostatic portion of the urethra (see p. 1263).
Just before it reaches the prostate gland each ductus deferens presents an irregular spindle-shaped enlargement, the ampulla (figs. 1019, 1020), whose walls are somewhat sacculated. Just beyond this it is joined upon its lateral surface by a club-shaped lobulated structure, the vesicula seminalis (fig. 1019). Each vesicle measures 4.5-5.5 cm. in length and has a greatest diameter of about 2 cm. It rests upon the posterior surface of the bladder, lying parallel with and lateral to the corresponding ductus deferens, and in its upper one-third is in relation posteriorly with the peritoneum which forms the anterior wall of the rectovesical pouch, while below it is in contact with the anterior wall of the lower part of the rectum, through which it may be palpated. Indeed, the two vesiculee, together with the ductus deferentes, form the lateral boundaries of the triangular area at the base of the bladder, throughout which that organ is in relation to the rectum.
Each vesicle is enclosed within a fine capsule of connective tissue, which contains numerous non-striated muscle fibres and is continuous below with the capsule of the prostate gland. On removing this capsule the vesicle will be found to consist of a greatly coiled tube, 10-12 cm.
in length, which ends blindly and has attached to it on either side a number of short diverticula (fig. 1020). The walls of the tube and diverticula are formed of smooth muscle tissue, arranged in layers similar to those of the ductus deferentes, and are lined by a much folded mucous
THE SPERMATIC CORD
membrane, whose cells contain considerable quantities of a yeUowish-brown pigment, and also contribute a secretion to the seminal fluid. In addition to having this function the vesiculse also serve as receptacles for the spermatozoa. They arise as diverticula from the embryonic ductus deferens, and it is worthy of note that a number (4 or 5) of similar but quite small diverticula arise from the upper part of each ductus ejaculatorius.
Vessels and nerves. — The artery supplying the ductus deferens is the a. deferentialis, a branch of the superior vesical. It accompanies the ductus to the tail of the epididymis and also gives a branch to the vesicula seminalis. The latter also receives branches from the middle haemorrhoidal and inferior vesical arteries. The deferential vein accompanies the ductus deferens to the base of the bladder where it breaks up into a plexus that communicates with the seminal venous plexus formed by the veins from the seminal vesicles. This joins with the vesical and pudendal ple.xus and so communicates with the hypogastric vein. The lymphatics of the ductus deferentes and seminal vesicles pass to the external iliac and hypogastric nodes. The nerves of both structures are derived from the hypogastric plexus.
The spermatic cord. — In its descent through the inguinal canal into the scrotum the testis necessarily drags after it the ductus deferens and the testicular vessels and nerves, these structures coming together at the abdominal inguinal
V. spermatica ext.
ring to form what is termed the spermatic cord [funiculus spermaticus]. This structure extends, therefore, from the abdominal inguinal ring, through the inguinal canal and the neck of the scrotal sack to the testis, and is enclosed within the same investing layers as the testis.
Thus as it emerges from the subcutaneous inguinal ring it receives an investment of connective tissue continuous with the intercrural fibres and the aponeurosis of the external oblique muscle. This cremasteric fascia has beneath it bands of striated muscle tissue, the external cremaster muscle (fig. 1021), especially developed on the posterior surface of the cord and continuous with the internal oblique muscle of the abdomen, and within these is an indistinct layer of connective tissue, the tunica vaginalis communis, which is received at the abdominal inguinal ring where it is continuous with the fascia transver.saUs.
Within the sheath thus formed there is a matrix of connective tissue, usually containing considerable amounts of fat and strands of non-striated muscle tissue, which form what is termed the internal cremaster muscle {funicular portion), and imbedded in this connective tissue are the various essential constituents of the cord. These are as follows (figs. 1017, 1021) : (1) the ductus deferens, occupying the posterior surface of the cord and having associated with it the deferential artery and veins and the deferential plexus of nerve fibres; (2) the internal spermatic artery, which occupies the axis of the cord and is surrounded by (3) the internal spermatic veins, which form a complicated network, known as the pam-
piniform plexus; (4) the testicular lymphatics; and (5) the internal spermatic plexus of nerves from the hypogastric plexus; and (6) branches of the genitofemoral nerve for the supply of the external cremaster muscles.
3. When this erectile tissue becomes engorged with blood the organ assumes an erect position, but otherwise it is pendulous, hanging downward in front of the scrotum from its attachment to the symphysis pubis.
The body of the penis in its flaccid condition is almost cylindrical, but in erection it becomes somewhat triangular in section, what was the anterior surface or dorsum penis* becoming flattened, while the opposite one, the urethral surface [facies urethralis], becomes more sharply rounded. The glans is separated from the body by a constriction, the ?ieck [coUum glandis], and from this region a fold of integument arises, which more or less completely encloses the glans, forming the prepuce [prseputium] (fig. 1024). The prepuce is quite free from the glans dorsally but in the ventral mid-line it is attached to it, almost to the urethral
The base of the glans has a wellmarked rounded border, the corona [corona glandis], and is deeply concave for the reception of the distal ends of the corpora cavernosa penis.
Immediately below it there is a layer of nonstriated muscular tissue, the dartos, and beneath this a layer of loose connective tissue, containing the superficial vessels and nerves of the penis; beneath this again is a denser, elastic sheet of connective tissue, the fascia penis (fig. 1022), which encloses the erectile bodies as far as the base of the glans and is continuous with the superficial fascia of the perineum and inguinal region. Where it passes beneath the symphysis pubis it receives from the anterior surface of the latter a strong band of fibrous tissue, which forms the suspensory ligament of the penis [Hg. suspensorium penis].
Two of the erectile bodies of the penis, the corpora cavernosa penis, are paired (fig. 1023). They are attached at their proximal ends to the base of the tuberosity of the ischium, and in this part of their extent are termed the c7-ura penis, being
THE PENIS 1261
composed of fibrotis connective tissue, whicli lias resting upon it the m. ischiocavernosus (see Section IV). The two crura are situated in the lateral portions of the superficial perineal interspace and pass forward parallel with the rami of the ischia and pubis, gradually becoming transformed into cavernous erectile tissue. Shortly before they reach the level of the symphysis pubis the two corpora come into contact in the median hne, their medial walls fusing to form a septum, and thus united they extend throughout the entire length of the body of the penis, occupying the dorsal portion of the space enclosed by the fascia penis (fig. 1022) . They terminate at the posterior surface of the glans, where they taper
somewhat to be received into its basal concavity (fig. 1024). The septum in its proximal part forms a complete partition between the two bodies, but distally it is broken through by numerous clefts by which the blood lacunse of the two bodies are placed in communication.
Each corpus cavernosum penis consists of a strong elastic fibrous sheath, the tunica albuginea, from which trabeculiB extend into the substance of the organ, dividing it into a network of communicating cavities, into which open terminal branches of the a. profunda penis, which traverses the axis of the corpus. These cavities consequently are to be regarded as vascular lacunae, which, becoming engorged with blood, produce the enlargement and erection of the organ.
The third erectile organ is the corpus cavernosum urethra (formerly "corpus spongiosum") (fig. 1023), so called because it is traversed throughout its entire length by the urethra (fig. 1024). It is an unpaired, median structure, having no
bony attachments and begins posteriorly in the superficial perineal interspace with an enlargement, the bulb [bulbus urethrae] (fig. 1023), whose posterior surface rests on the superficial fascia of the urogenital trigone and is enclosed by the m. bulbo-cavernosus. Anteriorly the bulb gradually tapers to a rather slender cylindrical portion, the body, very uniform in diameter, which extends throughout the entire length of the body of the penis, lying in the median hne beneath the fused corpora cavernosa penis (figs. 1022, 1023). At the neck of the penis it undergoes a sudden enlargement to form the glans, the whole of that structure, which has already been described, being formed by the corpus cavernosum urethras. The structure of the corpus cavernosum urethrae is essentially the same as that of the corpora cavernosa penis, the tunica albuginea, however, being much thinner.
Vessels and nerves. — The principal arterial supply of the penis is derived from the internal pudendal artery (see p. 610), although the proximal portion of its integument is also supplied by the external pudendal branches of the femoral artery. The veins from the integument
Fossa navicularis
collect into one or more stems, the superficial dorsal veins, which run along the dorsal mid-line and, diverging, open into the great saphenous vein. The deep veins from the corpora cavernosa open into a median deep dorsal vein, which connects partly with the internal pudendal veins and partly with the pudendal plexus. Both the superficial and deep lymphatics terminate in the superficial inguinal nodes. The lymph-vessels from the glans are said to follow those of the urethra and end in the deep inguinal and external iliac nodes.
Sympathetic fibres also
pass to the penis from the hypogastric plexus and with these fibres from the third and fourth sacral nerves, which constitute what is termed the nervus erigens, since stiinulation of it produces erection of the organ. An anatomical provision for the production of this phenomenon has been found in the occurrence of peculiar thickenings of the intima of the arteries of the penis, by which the lamina of the vessels are greatly diminished or even occluded when in a state of moderate contraction, as when the organ is flaccid. When the arteries are dilated the intimal thickenings become reduced in height and the blood is afforded a free passage into the lacunar spaces of the corpora cavernosa, which thus become engorged.
THE MALE URETHRA
In its course (fig. 1024) it traverses first the prostate gland, then the urogenital diaphgram and then the entire length of the corpus cavernosum urethrse, and may thus be regarded as being composed of three portions.
The prostatic portion [pars prostatica] (fig. 1024) extends almost vertically downward from the neck of the bladder, traversing the substance of the prostate gland. In its proximal part there is on its posterior wall a median longitudinal ridge, the crista urethralis, which below dilates into an oval enlargement, the colliculus seminalis (figs. 1015, 1025), to accommodate which there is a marked
Follicular glands of dorsal wall — VmL ;. At the centre of the colliculus there is an elongated opening of a pouch of varying depth, termed the utricnlus prostaticus ("uterus masculinus"), which corresponds to the lower part of the vagina in the female (see p. 1279). Situated one on either side of this are the much smaller openings of the ejaculatory ducts. Owing to the prominence formed by the coUiculus a section of the urethra in this region is somewhat fl-shaped, and at the bottom of the furrows on either side of the median eleva-
On its emergence from the prostate gland the urethra at once penetrates the deep layer of fascia of the urogenital trigone and enters the deep perineal interspace, this portion of its course being known as the membranous portion [pars membranacea]. Its direction is now downward and slightly forward, curving beneath the subpubic ligament, from which it is separated by a plexus of veins and by the fibres of the sphincter urethras membranaceae, which form an almost complete investment for it. The lumen of this part of the urethra is much narrower than that of the prostatic portion, and since it traverses the rather unyielding fasciae of the urogenital trigone it is less dilatable than in other parts of its extent, with the exception of the external orifice.
Passing through the superficial layer of fascia of the urogenital trigone the urethra then enters the bulb of the corpus cavernosum urethrae (fig. 1024) and is invested throughout the remainder of its extent by this structure, whence this portion is known as the cavernous portion [pars cavernosa]. In its proximal part this hes in the superficial interspace of the perineum and passes almost directly forward; but more distally, where it enters the body of the penis, it accommodates itself to the position of that organ, which it traverses lengthwise, lying in the midline near its ventral surface (fig. 1022). Thus the proximal portion of the cavernous and the whole of the membranous and prostatic portions have a fixed position, whence they are sometimes associated as the pars fixa of the urethra, while the penial portion forms the pars mobilis. On entering the bulb the lumen of the urethra dilates somewhat and in this region has opening into it the ducts of the bulbo-urethral glands (fig. 1025), but as it enters the body of the corpus cavernosum it diminishes again and maintains a uniform diameter throughout the extent of that structure. When it reaches the glans penis it undergoes another dilation, which is known as the fossa navicularis (fig. 1025), beyond which it diminishes to the slit-hke external orifice, situated at the extremity of the glans and forming the least dilatable portion of the entire urethral canal.
Throughout the greater part of its extent the cavernous portion of the urethra shows upon its dorsal wall the openings of numerous tubular depressions of the mucous membrane, the urethral lacunm [lacunas urethrales (Morgagnii)]. One of these, the lacuna magna, situated m the mid-dorsal line of the proximal part of the fossa navicularis, has its orifice guarded by a valve-hke fold [valvula fossEe navicularis] of the mucous membrane and is sufficiently large to receive the point of a small catheter. Numerous minute glands [gl. urethrales] open upon the surface of the urethral mucosa. They are most abundant in the anterior wall, but occur also on the sides and floor.
,.„ Dimensions of the urethra.— The entire length of the urethra is somewhat variable in ditterent individuals, the greatest variation being in the length of the pars mobihs. Of the pars fi^a the prostatic portion is 2.5-3.0 cm. in length, the membranous portion about 1.0 cm., and the fixed part of the cavernous portion 6.5 cm., the entire pars fixa having thus a length of somewhat over 10.0 cm. (4 in.). The average diameter of the urethra is 5.0-7.0 mm., but it will be noted that the canal presents in its course three dilatations; namely, (1) at the fossa navicularis, which begins about 0.5 cm. from the external orifice; (2) the bulb of the corpus cavernosum urethras; and (3) in the prostatic portion. Furthermore there are two regions in which it is distinctly narrowed; namely, at the external orifice and in the memjjranous portion. While the remaining portions are capable of considerable distention, these are relatively indistensible, the maximum diameter to which they may be dilated being about 10 mm. Arranged in an ascending order according to their capability for distention the parts would have the followmg order: external orifice, membranous portion, penial portion, prostatic portion, bulbar portion.
5. The Prostate Gland
The prostate gland [prostata] (figs. 1013, 1019, 1024 and 1025) is a mass of glandular and muscular tissue surrounding the proximal portion of the male urethra, and may, indeed, be regarded as a special development of the wall of this portion of the canal. It is a more or less flattened conical structure whose base [basis prostatse] is in contact with the lower surface of the bladder and the apex [apex prostatse] with the deep fascia of the urogenital trigone. Its anterior surface [facies anterior] is in relation with the symphysis pubis, from which it is separated by the pudendal plexus of veins, and posteriorly [facies posterior] it is separated from the lower portion of the rectum only by some loose connective tissue; laterally it is in relation with the levatores ani, receiving an investment from the endopelvic fascia covering these.
The urethra enters the base of the gland near its anterior border and traverses it almost vertically, so that the greater portion of the gland is posterior to the canal. On the posterior surface of the gland is a more or less distinct median vertical groove, which serves to separate the lateral portion as the lateral lobes [lobus dexter et sinister], although the demarcation is merely a superficial one. The groove terminates above in a well-marked notch on the posterior border of the base, and immediately in front of this there is a deep funnel-shaped depression of the surface, which receives the ejaculatory ducts. Beginning at this depression two grooves pass forward and slightly lateralward across the surface of the base, marking off a more or less pronounced median elevation, which constitutes what is termed the middle lobe [lobus medius] (fig. 1024); since this lies beneath the trigone of the bladder behind the internal orifice of the urethra its enlargement may produce more or less occlusion of the latter.
Dimensions. — The longest axis of the prostate, which is almost vertical in the erect posture measures 2.5-3.0 cm., the transverse diameter at the base is 4.0-4.5 cm. and the thickness 2.0-2.5 cm. Its iveight is normally 20-25 grms. but in old age it may be double that, its dimensions having correspondingly increased.
Structure. — The prostate consists of some 15-30 branched tubular glands imbedded in a matrix of connective tissue, containing a large amount of non-striped muscle tissue and forming at the surface of the gland a strong fibro-muscular capsule from which prolongations are contributed to the pubo-vesical ligaments and muscles. The glands, which vary greatly in their development, are outgrowths from the mucous membrane of the urethra, into which their ducts open at the bottom of the grooves that lie lateral to the colliculus seminahs; similarly, the matrix with its muscle tissue is evidently the modified muscular coat of the urethra. Consequently there is no distinct demarcation between the wall of the urethra and the substance of the gland, and from the developmental standpoint the gland is to be regarded as the modified wall of the urethra.
The facts that the prostate shows a special development at puberty and undergoes more or less extensive degenerative changes with the cessation of the reproductive function, as seen in old age and in castrates, indicate that it is associated physiologically with the reproductive organs. Its secretion is a thin alkaline fluid, which may contain round or elongate, concentrically layered bodies, measuring 0.3-0.5 mm. in diameter and known as amyloid bodies, although they are really albuminous in chemical composition. They are constantly found in adults in the lumina of the glands and may become calcified. The secretion has been found to have a stimulating effect upon the spermatozoa, and this may be its principal function.
Vessels and nerves. — The arterial supply of the prostate is derived from the inferior vesical and middle hemorrhoidal branches of the hypogastric artery. The veins form a rich prostatic plexus in the immediate vicinity of the gland, this being part of the general plexus at the base of the bladder and communicating posteriorly with the seminal plexus and anteriorly with the pudendal plexus. It drains finally into the hypogastric vein. The lymphatics are very abundant and form a network on the posterior surface of the gland -from which four principal vessels pass to the hypogastric nodes. The nerves are derived from the hypogastric plexus.
The bulbo-urethral glands [gl. bulbo-urethralis (Cowperi)] or Cowper's glands (figs. 1024, 1025) are two small tubulo-alveolar glands which fie one on either side of the membranous portion of the urethra, imbedded among the fibres of the sphincter urethrse membranacete, between the two layers of fascia of the urogenital trigone. Each is a rounded body with a diameter of 4.0-9.0 mm. and is drained by a duct [ductus excretorius] which perforates the superficial fascia of the trigone and, entering the substance of the bulb of the corpus cavernosum urethrse, traverses it to open on the floor of the bulbar portion of the urethra after a total course of 3.0-4.0 cm. Nothing is definitely known as to the nature of the secretion or the functions of the glands.
The organs of reproduction in the female consist of (1) the ovaries, the essential organs of reproduction; (2) the tubce uterince (Fallopian tubes), which serve as ducts for the conveyance of the ova to (3) the uterus, in which the embryo normally undergoes its development; (4) the vagina, a canal by which the uterus is placed in communication with the e.xterior; and (5) the external genitalia. In addition it will be necessary to consider here the female urethra, although it differs from that of the male in that it serves merely as a passage for the contents of the bladder and does not transmit the reproductive elements.
Broad ligament. — ^The first three of these structures are entirelj^ contained within the true pelvis and are associated with a transverse fold of peritoneum which rises from the floor of the pelvic cavity between the bladder and the rectum, incompletely dividing the cavity into an anterior and a posterior compartment. It is known as the hroad ligament of the uterus [lig. latum uteri] (fig. 1026). The broad ligament appears to extend laterally from the sides of the uterus to the lateral walls and floor of the pelvis, although in reality it extends across the pelvic cavity from side to side and encloses the uterus between the two layers of which it is composed. It is attached to the floor of the pelvis below, where the two layers are reflected, the one upon the anterior wall of the pelvis and the posterior and superior surfaces of the bladder, and the other posteriorly over the floor of the pelvis to the posterior pelvic wall and the rectum, forming the anterior wall of a deep depression between the rectum and uterus, known as the recto-uterine pouch (of Douglas) [excavatio rectouterina (cavum Douglasi)] (fig. 1035). Its lower border also passes upward upon the sides of the pelvis, resting upon the pelvic fascia, but its lateral borders are free, extending between the lateral wall of the pelvis and the extremity of the tuba uterina on each side and forming what are termed the infundibulo-pelvic ligaments. The upper border is also free and contains the tuba uterina on either side, and the fundus of the uterus in the midline (fig. 1027).
Epodpliorou
Attached to the posterior layer of the broad hgament a httle below its upper border and therefore projecting into the posterior compartment of the pelvis, there is a horizontal shelf, termed the mesovarium, since it has the ovary attached to its free edge (fig. 1027). The portion of the broad hgament above this is known as the mesosalpinx (salpinx = tuba), while that below istermed the mesometrium (metra= uterus). The remaining structm-es that occur between the two layers of the broad ligament will be described with the organs with which they are associated, but it is to be noted that the ligament in its upper part is broader than the transverse diameter of the pelvic cavity and its sides are accordingly folded back upon the lateral walls of the cavity, following the course of the tuba uterina.
The broad ligament is the adult representative of the fold of peritoneum which encloses the embryonic excretory organ, the mesonephros. This is for a time a voluminous organ, projecting under cover of the peritoneum from the dorsal wall of the abdomen and bearing upon its medial wall a thickening, the genital ridge (fig. 1028 A), from which the reproductive gland develops. In the free edge of the peritoneum enclosing it two ducts occur, the Wolffian duct, which is the duct of the excretory organ and becomes the ductus deferens of the male, and the Miillerian duct. With the progress of development the two MuUerian ducts fuse in the lower portions of their course to form the uterus and vagina (prostatic utriculus of the male), while in their upper parts they remain separate and form the tubs uterinae. By this fusion the two peritoneal folds are brought into continuity at their edges, and (the mesonephros degenerating on the formation of the permanent kidney) constitute the broad ligament (fig. 1028 B). This structure therefore contains between its two layers the uterus and the remains of the mesonephros, and has the ovary attached to its posterior surface. In the male what corresponds to the broad hgament fuses with the peritoneum covering the posterior surface of the bladder.
1. The Ovaries
Form and position. — The ovarie,s [ovaria] are two whitish organs, situated one on either side of the pelvic cavity. Each has somewhat the shape of an almond (fig. 1026). It is attached by one of its edges [margo mesovaricus] to the border of the mesovarium, and since it is along this line of attachment that the vascular and nerve supply enters the substance of the organ, this border is spoken of as the hilus [hilus ovarii]. The opposite border is free [margo liber]. The larger rounded end is directed toward the free extremity of the tuba uterina and hence is known as the tubal extremity [extremitas tubaria], while the other, the uterine extremity [extremitas uterina], is directed toward the uterus; the two surfaces, owing to their topographic relations, are known as the lateral and medial surfaces [facies mediahs et lateralis].
Transverse vesical fold
The exact position of the ovary in the pelvis is subject to some variation, but typically it hes almost in a sagittal plane (fig. 1029) against the lateral wall of the pelvis, resting in a distinct depression, the /ossa ovarica, lined by peritoneum and bounded above by the external iliac vessels and behind by the ureter and uterine artery, while beneath its floor are the obturator vessels and nerve. The long axis of the ovary is almost vertical when the body is erect, the tubal pole being upward; the mesovarial border is directed forward and laterally, its free border dorsally and medially while its surfaces look almost laterally and medially.
Frequently, however, the uterus is displaced to one side, dragging the uterine extremity of the opposite ovary (by the attachment of the ovarian ligament) toward the mid-plane. The long axis of the ovary thus becomes oblique, approaching more or less the horizontal. The ascending portion of the tuba uterina rests upon its mesovarial border and the fimbriated mouth
THE UTERINE TUBES 1269
of the tube is in contact with its medial surface. When enlarged the ovary may be felt through lateral wall of the vagina and, better, through that of the rectum; and its position with regard to the surface may be indicated by a point midway between the anterior superior spine of the ilium and the symphysis pubis or the opposite pubic tubercle.
The position assumed by the ovary is due to its attachment to the edge of the mesovarium and to the upper portion of the broad hgament being broader than the diameter of the pelvis, so that it is folded back upon the lateral walls of the cavity. In addition to its attachment to the broad hgament through the mesovarium, the ovary is also connected to the side of the uterus by the ovarian ligament [hg. ovarii proprium] (fig. 1026), a' band of connective tissue with which numerous non-striped muscle fibres are intermingled. It lies between the two layers of the broad hgament, on the boundary line between the mesosalpinx and the mesometrium, and extends from the uterine pole of the ovary to the side of the uterus. Here it is attached just below the origin of the tuba uterina and above the point of attachment of the round hgament of the uterus, with which it is primarily continuous. Another Hgament, termed the suspensory ligament of the ovary (figs. 1029, 1034), extends laterally between the two layers of the broad hgament from the tubal extremity of the ovary to the pelvic walls, forming the lateral portion of the lower boundary of the mesosalpinx. It is formed by the vessels and nerves (internal spermatic) passing to and from the ovary, and from the point where it meets the lateral pelvic wall it may be traced upward for some distance upon the posterior wall of the abdomen, behind the peritoneum, which it elevates into a more or less distinct fold, whose lateral wall on the right side becomes continuous above with the peritoneum lining the subccecal fossa.
Size. — The size of the ovary varies considerably, that of the right side being as a rule somewhat larger than that of the left. The length may be anywhere from 2.5 cm. to 5.0 cm., the breadth about half the length and the thickness half the breadth. Its average weight in the adult is from 6.0 to 8.0 grms., but in old age it may fall to 2.0 grms.
Structure. — The ovary is covered by a layer of columnar epithehum which is continuous with the peritoneal epithelium along the line of the attachment of the mesovarium; the ovary consequently is not covered by peritoneum, but is rather to be regarded as a local thickening of the peritoneum. Its substance is a network of connective tissue, in which non-striped muscle fibres also occur, and is known as the stroma. The more central portions of this are largely occupied by blood-vessels but in the cortical portions are multitudes of immature ova, surrounded by their follicle cells [follicuU oophori primarii]; and also numbers of cavities of various sizes, lined with foUicle cells and filled with fluid, each containing an ovum [ovulumj in a more or less advanced stage toward maturity. These are the Graafian follicles [follicuU oophori vesiculosi (Graafi)], and as they ripen they increase in diameter and approach the surface, upon which they may form marked prominences. When mature the follicles burst, allowing the escape of the ovum, scars being thus formed upon the surface of the ovary that are known as corpora albicantia. If, however, the ovum becomes fertilized and pregnancy results the walls of the follicle undergo a remarkable development, forming what is known as a corpus luteum.
Epoophoron and paroophoron. — Closely associated with the ovaries are two rudimentary organs situated between the layers of the mesosalpinx and representing remains of the mesonephros of the embryo. The larger of these is the epoophoron (fig. 1030). It consists of a longitudinal duct [ductus epoophori longitudinalis (Gartneri)], lying parallel with the tuba uterina and closed at either extremity, and 10-15 transverse ducts [ductuli transversi], which open into the longitudinal duct. It is the remains of the upper or reproductive portion of the mesonephros and therefore is the homologue of the epididymis of the male. In addition there is frequently to be found in the neighbourhood of the epoophoron and close to the mouth of the tuba uterina one or more stalked, oval cysts, the appendices vesiculosi {hydatids of Morgagni), which may reach the size of a small pea.
The other organ is the parobphoron; it is much smaller than the epoophoron and usually disappears before adult life, but when present consists of a small group of coiled tubules, more or less distinct, representing a portion of the excretory portion of the mesonephros. Its equivalent in the male is therefore the paradidymis.
Vessels and nerves. — The chief artery is the ovarian, which together with the ovarian veins and lymphatics passes to the ovary in the suspensory ligament. An additional blood supply is furnished by the ovarian branch of the uterme artery. The veins follow the course of the arteries. As they emerge from the hilus they form a weU-developed plexus (pampiniform plexus) between the laj'ers of the mesovarium. Unstriped muscle fibres occur in the meshes of the plexus and the whole structure has much the appearance of erectile tissue. The lymphatics accompany the blood-vessels and terminate in the lumbar nodes. Nerves pass to the ovary with the ovarian artery from the renal and aortic sympathetic plexus.
with the superior angles of the uterus and running in the superior border of the broad hgament (mesosalpinx) to come into relation with the ovaries at their distal extremities. Each tube opens proximally into the uterine cavity and distally communicates witli the pelvic portion of the peritoneal cavity by a funnelshaped mouth, the ostium abdominale, which under normal conditions is closely applied to the surface of the ovary, so as to receive the ova as they are expelled from the Graafian follicles. Each tube is from 7 to 14 cm. in length and consists of a narrow straight portion, the isthmus, immediately adjoining the uterus, followed by a broader, more or less flexuous portion, the mnpulla, which terminates in a funnel-like dilatation, the infundibulum. The margins of the infundibulum are fringed by numerous diverging processes, the fimbria, one of which, the fimbria ovarica, is much longer than the rest and extends along the free border of the mesosalpinx (the infundibulo-pelvic ligament) to reach the tubal pole of the ovary.
The course of each tube is at first almost horizontally laterally and backward from its attachment to the uterus, until it reaches the lateral wall of the pelvis and there comes into relation with the uterine extremity of the ovary (figs. 1029, 1034). It then bends at right angles and passes almost vertically upward
Anterior peritoneal lamina
along the mesovarial border of the ovary until it reaches its tubal extremity, where it curves downward and backward so that the mouth of the infundibulum and the fimbriae rest upon the medial surface of the ovary.
Structure. — The tubas occupy the upper free edge of the mesosalpinx and are therefore enclosed within a peritoneal covering [tunica serosa] except a small strip along their lower surface (fig. 1027), and hence a rupture of one of them may lead to the escape of its contents either into the peritoneal cavity or into the subserous areolar tissue between the two laj'ers of the broad ligament. At the margins of the infundibulum and the borders of its fimbrite the peritoneal epithelium becomes directly continuous with the mucous membrane lining the interior of the tube. The subserous areolar tissue [tunica adventitial in the immediate vicinity of the tube is lax and contains the blood-vessels and nerves by which the tube is supplied; it forms a loose connection between the peritoneum and the muscular wall [timica muscularis] of the tube. This consists of two layers of non-striped muscle fibres, an outer longitudinal and an inner circular one, and reaches its greatest development toward the uterine end of the tube. The inner layer [tunica mucosa] of the tube is hned by a columnar cihated epithelium which is raised into numerous folds, simple in the region of the isthmus, but becoming higher and more complex in the ampulla, where, in transverse sections, the lumen seems to have a lab3Tinthine form. The beat of the cilia is toward the uterus.
Vessels and nerves. — The arteries of the tubaj are derived from the ovarian and uterine, each of which gives off a tubal branch, which pass between the two layers of the mesosalpinx, the one medially and the other laterally, and anastomose to form a single stem. The veins accompany the arteries. The lymphatics accompany those from the ovary and fundus uteri and terminate chiefly in the lumbar nodes. The nerves of the ampuUa are given off from the branches passing to the ovary, while those of the isthmus come from the uterine branches.
The uterus (fig. 1031) is an unpaired organ, situated between the two layers of the broad ligament and communicating above with the tubse uterinse and below with the vagina. It is pyriform in outhne, although flattened antero-posteriorly (fig. 1032) and it is divided into two main portions, the body [corpus uteri] and the cervix by a transverse constriction, the isthmus.
Cervical attaciiment of vagina
who have borne children, is much larger than the cervix, although the reverse is the case in children. In young girls the two parts are about equal in size. The anterior or vesical surface [fades vesicalis] is almost flat (fig. 1032), while the posterior or intestinal surface [facies intestinalis] is distinctly convex, the two surfaces meeting in well-marked rounded borders, at the upper extremities of which the tubas uterinse are attached. The superior border which extends between the points of attachment of the two tubse is thick and rounded and forms
what is termed the fundus uteri. The cavity [cavum uteri] of the body is reduced to a fissure by the antero-posterior flattening of the walls and has a triangular form (fig. 1033), broad above where it communicates on either side with the cavity of a tuba uterina and narrow below where it communicates with the cavity of the cervix, this communication, which corresponds in position with the isthmus, forming what is known as the internal orifice [orificium internum] (internal os uteri). The cervix is more cj'lindrical in form, though slightly expanded in the middle
of its length, and is divided into a suTpravaginal [portio supravaginalis] and a vaginal -portion [portio vaginalis] by the attachment to it of the vagina (fig. 1031). The line of this attachment is obhque, about one-third of the anterior surface of the cervix and about one-half of the posterior surface belonging to the vaginal portion. At the lower extremity of the cervix is the external orifice [orificium externum] (external os uteri), which is round or oval before parturition has taken place and is bounded by two prominent labia, anterior and posterior, the anterior one [labium anterius] being shorter and thicker than the posterior [labium posterius] and reaching a lower level (fig. 1032). In women who have borne children the external orifice assumes a more slit-like form and the labia become notched and irregular. The cavity of the cervix, known as the canal of the cervix [canaHs cervicis], is fusiform in shape, and extends from the internal to the external orifice. On its anterior and posterior walls are folds known as the plicce palmatce (fig. 1033), consisting of a median longitudinal ridge from which shorter elevations extend laterally and slightly upward; these are most distinct in young individuals and are apt to become obliterated by parturition.
Vaginal wall
Position and relations. — The direction of the axis of the uterus is apparently variable within considerable limits, not only in different individuals, but also in any one individual in correspondence with the degree of distention of the bladder anteriorly and the rectum posteriorly. In what may be regarded as the typical condition (fig. 1034) the external orifice lies at about the level of the upper border of the symphysis pubis and in the plane of the spines of the ischia. From this point the axis of the cervix is directed upward and slightly forward, the lower level of the anterior labium being thus brought about. The entire uterus is, accordingly, anteverted, and, furthermore, the body is bent forward (anteflexed) upon the cervix at the isthmus, the axis of the two portions making an angle, open anteriorly, of from 70° to 100°. Frequently, also, the body is sHghtly inclined either to the right or to the left.
The anterior surface of the uterus rests upon the upper and posterior surfaces of the bladder (fig. 1029), from which the body is separated by the utero-vesical pouch of peritoneum. The anterior layer of the broad ligament as it passes over the anterior surface of the uterus forms the posterior wall of this pouch and is reflected forward to the superior surface of the bladder at about the level of the isthmus (fig. 1034), so that the whole of the anterior wall of the cervix is below the floor of the pouch and is separated from the posterior surface of the bladder only by connective tissue. Posteriorly, however, the peritoneal covering of the uterus, which here forms the anterior wall of the recto-uterine pouch, e.xtends down as far as the uppermost portion of the vagina and consequently invests the entire surface of the uterus, whose convex posterior wall is thus separated from the rectum by the recto-uterine pouch (figs. 1029, 1035). Coils of the small intestine rest upon the posterior surface of the body and may also be interposed between the cervix and the rectum. An important relation is that of the ureters to the cervix, these ducts, as they pass to the bladder, running parallel with the cervix at a distance of from 8 to 12 mm. from it.
of the uterus, immediately below the point of attachment of the ovarian ligament, the ligamentum teres (round ligament) (fig. 1030), which is a fibrous cord contaioing non-striped muscle tissue. It extends downward, laterally and forward between the two layers of the mesometrium toward the abdominal inguinal ring, and, traversing this and the inguinal canal, it terminates in the labium majus by becoming continuous with its connective tissue.
It is accompanied by a funicular branch of the ovarian artery and a branch from the ovarian venous plexus, and in the lower part of its course by a branch from the inferior epigastric artery, over which it passes as it enters the abdominal ring. In its course through the inguinal canal it is accompanied by the iho-inguinal nerve and the external spermatic branch of the genitofemoral.
The utero-sacral ligaments are flat fibro-muscular bands which extend, one on each side, from the upper part of the cervix uteri to the sides of the sacrum opposite the lower border of the sacro-iliac articulation. They produce the rectouterine folds (fig. 1029) of peritoneum, which form the lateral boundaries of the mouth of the recto-uterine pouch (of Douglas) and their muscle fibres [m. rectouterinus] are continuous at one extremity with the muscular tissue of the uterus and at the other with that of the rectum.
Structure. — The portion of the broad ligament that invests the uterus forms the serous covering [tunica serosa] of the organ and is sometimes termed the perimetrium. Over the fundus and the greater portion of the body it is thin and firmly adherent to the subjacent muscular substance of the uterus, so that it cannot readily be separated from it. Over the posterior surface of the cervix and the lower part of the anterior surface of the body, however, it is thicker, and is separated from the muscular substance by a layer of loose connective tissue, the parametrium, which also extends upward along the sides of the uterus between the two layers of the broad hgament, with whose subserous areolar tissue it is continuous. Owing to this disposition of the parametrium the whole of the cervix may be amputated without encroaching upon the peritoneal cavity.
The main mass of the uterus is formed by the muscle tissue [tunica muscularis] or myometrium, whose fibres have a very complicated arrangement. Two principal layers may be distinguished, an outer, wealv one, composed partly of longitudinal fibres continuous with those of the tub® uterinje, and of the round and utero-sacral hgaments, and a much stronger inner one, whose fibres run in various du-ections and have intermingled with them in the body of the uterus large venous plexuses. The inner surface of the myometrium is hned by a mucous membrane [tunica mucosa] or endometrium, which has a thickness of from 0.5 to 1.0 mm. and is composed of tissue resembling embryonic connective tissue, bearing upon its free surface a single layer of cihated columnar epithelium. On account of its structure the tissue is rather delicate and friable, and numerous simple tubular glands, which open into the cavity of the uterus, traverse its entire thickness. In the cervix the mouths of some of the glands may become occluded, produci^g retention cysts, which appear as minute vesicles projecting from the surface between the plicse palmatae; they are known as ovula Nabothi, after the anatomist who first described them.
Vessels and nerves. — The principal artery of the uterus is the uterine, whose terminal portion ascends along the lateral border of the uterus in a tortuous course through the parametrium, giving off as it goes lateral branches to both surfaces of the uterus. Above, it anastomoses with the ovarian artery, which thus forms an accessory source of blood supply during pregnancy. The veins form a plexus that is drained by the ovarian and uterine veins, a communication with the inferior epigastric being also made by way of the vein accompanying the round ligament. The lymphatics from the greater portion of the body pass to the iliac nodes: those of the fundus accompany the ovarian vessels to the lumbar nodes. A vessel also accompanies the round hgament to terminate in one of the superficial inguinal nodes. The lymph-vessels from the cervix terminate in the external iliac, hypogastric and lateral sacral nodes.
The nerves of the uterus pass to it from two sympathetic gangha, situated one on either side of the cervix, whence they are termed the cervical gangha, and forming part of the plexus utero-vaginalis. Branches pass to the ganglia from the hypogastric plexus and also from the second, third and fourth sacral nerves.
4. The Vagina
The vagina (fig. 1034) is a muscular, highly dilatable canal lined by mucous membrane, and extends from the uterus to the external genitaUa, where it opens to the exterior. Its long axis is practically parallel with that of the lower part of the sacrum and it therefore meets the cervix uteri at a wide angle which is open anteriorly. Its anterior wall is, accordingly, somewhat shorter than the posterior, measuring 6.0-7.0 cm., while the posterior one is about 1.5 cm. longer. It becomes continuous with the cervix uteri some distance above the lower extremity of that structure, which thus projects into the lumen of the vagina, and there is so formed a narrow circular space between the wall of the vagina and
the vaginal portion of the cervix uteri. The roof of the space is formed by the reflection of the vagina upon the cervix and is termed the fornix. Owing to the greater length of the posterior wall of the vagina the portion of the circular space below the posterior fornix is considerably deeper than that below the anterior.
In its ordinary condition the lumen of the vaginal canal is a fissure, which in transverse section resembles the form of the letter H with a rather long transverse bar (fig. 1036). On both the anterior and the posterior wall there is in the median line a well-marked longitudinal ridge, the columna rugarum, which is especially distinct in the lower part of the anterior wall, where it lies immediately beneath the urethra and forms what is known as the urethral carina. From both columnse other ridges pass laterally and upward on either side, forming the rugw vaginales. Both these and the columnee diminish in distinctness with advance in age and with successive parturitions. Toward its lower end the vagina traverses the urogenital trigone, being much less dilatable in this region than elsewhere, and it opens below into the vestibule of the external genitalia. Its orifice is partially closed by a fold of connective tissue, rich in blood-vessels, and lined on both surfaces by mucous membrane. This membrane, known as the
It varies greatly in strength and development and although it is nearly always ruptured by the first act of sexual congress, it may remain unbroken until parturition. Rarely it takes the form of a complete imperforate curtain and may necessitate a surgical operation at the commencement of the menstrual periods. After rupture the remains of the hymen persist as small lobed or wart-like structures, the carunculoe hymenales, around the vaginal orifice.
Relations. — The uppermost part of the posterior wall of the vagina is in relation with the peritoneum forming the floor of the recto-uterine pouch (of Douglas), but elsewhere the canal is entirely below the floor of the peritoneal cavity. Posteriorly it rests almost directly upon the rectum (flg. 1036), and the contents of that viscus may be readily felt through its walls. Anteriorly it is in intimate relation with the urethra and the posterior wall of the bladder (figs. 1034, 1036), while laterally it is crossed obliquely in its upper third by the ureters as they pass to the base of the bladder, and in its lower two-thirds by the edges of the anterior portion of the levatores ani. The duct of Gartner, the remains of the lower portion of the Wolffian duct, may occasionally be found at the side of the
upper half of the vagina as a minute tube or fibrous cord. The external orifice is surrounded by the fibres of the bulbo-cavernosus muscle, which may be regarded as forming a sphincter {s-phinder vagince) .
Structure. — The wall of the vagina is formed mainly of non-striped muscle tissue, whose fibres are indistinctly arranged in two layers, an outer longitudinal and a less distinct inner circular one. Above, this tissue is continuous with that of the cervix uteri, as is also the mucous membrane which lines the lumen. This differs from that of the cervix in having a stratified squamous epithelium and in being destitute of glands.
Vessels and nerves. — The arteries of the upper part of the vagina are derived from the vaginal branch of the uterine; its middle portion is supplied by a vaginal branch from the inferior vesical and its lower part by the middle hssmorrhoidal and internal pudendal. The veins form a rich plexus on the surface and drain into the hypogastric vein. The lymphalics are very numerous and drain for the most part to the hypogastric and lateral sacral nodes; some of those from the lower portion of the canal joining with those from the external genitalia to pass to the inguinal nodes. The nerves passing to the vagina are derived from the utero-vaginal and vesical plexuses.
Posterior commissure
two folds of integument, the labia majora (fig. 1037). These anteriorly are continued into the mojis pubis, an eminence of the integument over the symphysis pubis due to a development of adipose tissue. The medial surfaces of the two labia are normally iii contact, the fissure between them being termed the rinia pudendi, and where they meet anteriorly and posteriorly they form the anterior and posterior commissures [commissura labiorum anterior et posterior]. Just anterior to the latter is an inconstant transverse fold, the frenuhim labiorum pudendi ("fourchette") (fig. 1037). The mons and the outer sm-faces of the labia are covered by short crisp hairs, but tlie medial surfaces of the labia are smooth, possessing only rudimentary hairs, but beset with large sebaceous and sudoriparous glands. The interior of the labia is occupied by a mass of fat tissue in which the distal extremity of the round ligament of the uterus breaks up.
FEMALE EXTERNAL GENITALIA
Within the depression bounded by the labia majora is a second pair of integumental folds, the labia yninora (fig, 1037), which difTer from the labia majora in being destitute of hairs and fat. They are usually concealed by the labia majora, but are sometimes largely developed and may then project through tlie rima pudendi, assuming a dried and pigmented appearance.
The labia minora divide and unite anteriorly over the distal extremity of the clitoris, forming the prcepuiiuni cliioridis in front of the clitoris, and the frenulum diloridis behind it. Posterior to this they diverge and reach their greatest height, gradually diminishing as they pass backward to terminate in a slight, inconstant, transverse fold, the frenulum labiorum pudendi, situated just anterior to the posterior commissure of the labia majora. Anterior to the frenulum is the fossa navicularis of the vestibule.
The vestibule. — The space between the two labia minora is termed the vestibule, and into its most anterior portion there projects the extremity of an erectile organ, the clitoris (fig. 1037), which is comparable to the penis of the male. It is, however, relatively small and is not perforated by the urethra, which lies below it. It is composed of two masses of erectile tissue, the corpora cavernosa clitoridis, which differ from the corresponding structures of the penis only in size. They are attached posteriorl3^ to the rami of the pubis by the cr^ira clitoridis (fig. 1038), and as they pass forward they converge and meet together to form the body of the organ, which, beneath the symphysis pubis, bends sharply upon itself
and passes posteriorly beneath the anterior commissure of the labia majora. Distally the corpora cavernosa abut upon another mass of erectile tissue, which fits hke a cap over their extremities; it is formed by an anterior prolongation of the bulbi vestibuli and is termed the glans clitoridis, being comparable to the glans penis, from which it differs only in not being perforated by the urethra.
A short distance posterior to the glans chtoridis is the opening of the urethra [orificium urethrse externum], situated upon the summit of a slight papilla-like elevation. Lateral to this orifice are sometimes found the openings, one on either side, of two elongated slender ducts, the 'paraurethral ducts (ducts of Skene). Still more posteriorly is the external orifice of the vagina [orificium vaginae], partially closed in the virgin bj^ the hymen. Lateral to this, in the angles between the hymen and the labium minus on either side, is the opening of the greater vestibular gland, while the lesser glands open at various points on the floor of the vestibule, sometimes at the bottom of more or less distinct depressions.
Beneath the floor of the vestibule and resting upon the superficial layer of the urogenital trigone are two oval masses of erectile tissue, the hidbi vestibuli (fig. 1038), homologous with the corpus cavernosum urethriE of the male. They consist principally of a dense network of anastomosing blood-vessels, enclosed within
a thin investment of connective tissue. From the main mass of each bulbus a slender prolongation, the pars intermedia, extends anteriorly past the side of the urethra, to form the glans clitoridis.
The greater vestibular glands [gl. vestibularis major (Bartholini)] or glands of Bartholin (fig. 1038) represent the bulbo-urethral glands of the male. They are two small, compound tubular glands, situated one on either side immediately posterior to the bulbi vestibuli.
The single duct of each gland opens on the floor of the vestibule in the angle between the hymen and the orifice of the vagina and a httle posterior to the mid-transverse line of the latter. Numerous small tubular glands occur in the integument forming the floor of the vestibule; they are termed the lesser vestibular glands and are especially developed in the interval between the urethral and vaginal orifices.
The muscles of the female external genitalia (fig. 1038) correspond to the perineal muscles of the male (see Section IV). There are two transverse perineal muscles, which have the same relations as in the male, and two ischio-cavernosi, which are related to the crura clitoridis just as those of the male are to the crura penis. The bulbo-cavernosi, however, present somewhat different relations, each being band-like in form, arising from the central point of the perineum and extending forward past the orifice of the vagina, over the greater vestibular gland and the bulbus, to form with its fellow of the other side a tendinous investment of the body of the clitoris. The two muscles act as a sphincter to the vagina and are sometimes termed the sphincter vagince.
The urethra. — The urethra of the female [urethra muKebris] (figs. 1034, 1036) corresponds only to the prostatic and membranous portions of the male and is a relatively short canal, measuring from 3.0 to 4.0 cm. in length. At its origin from the bladder it lies about opposite the middle of the symphysis pubis and thence extends downward and slightly forward to open into the vestibule between the glans clitoridis and the orifice of the vagina. Its posterior wall is closely united with the anterior wall of the vagina, especially in the lower part of its course where it forms the urethral carina of the vaginal wall; laterally and anteriorly it is surrounded by the pudendal plexus of veins.
Structure. — Its walls are very distensible, and are lined by a mucous membrane with numerous longitudinal folds, one of which on the posterior side is more prominent and is termed the crista urethralis. The mucosa contains numerous small glands [gl. urethrales], a group of which on each side is drained by the inconstant ductus paraurethrahs. External to the loose submucosa is a sheet of smooth muscle, whose fibres are arranged in an outer circular and an inner longitudinal layer, a rich plexus of veins lying between the two and giving the entire sheet a somewhat spongy appearance. The circular fibres are especially developed at the vesical end of the canal, forming there a strong sphincter, and striped muscle fibres, derived from the bulbo-cavernosus, form a sphincter around its vestibular orifice. The female urethra differs from that of the male in not being enclosed within a prostate gland; but what are probably rudiments of this structure are to be found in the groups of urethral glands drained by the paraurethral ducts.
Vessels and nerves. — The arteries supplying the external female genitalia are the internal and external pudendals, and the veins terminate in corresponding trunks. The lymphatics, which are very richly developed, drain for the most part to the inguinal nodes; those from the urethra pass to the iliac nodes. The nerves are partly sympathetic and partly spinal; the former are derived from the hypogastric plexus, the latter principally from the pudendal, the anterior portions of the labia majora being supplied by the iUo-inguinal and the external spermatic branch of the genito-femoral.
It has already been pointed out (p. 1267) that during development a transitory excretory organ, the mesonephros or WolfEan body, reaches a high degree of development, and its duct, the Wolffian duct, opens into a cloaca or common outlet for the intestinal and urinary passages. The mesonephros forms a strong projection from the posterior wall of the abdomen into the body cavity, and on the medial surface of the peritoneum which covers it a thickening appears which is termed the genital ridge. The upper part of this ridge becomes the ovary or testis, as the case may be, while the remainder of it becomes the ovarian and round ligaments in the female and the gubernaculum testis in the male.
As the ovary or testis develops the tubules of the upper part of the Wolffian body enter into relation with it, forming, indeed, in the case of the testis, a direct union with the seminferous tubules. The Wolffian body then becomes divisible into a reproductive and an excretory portion, and, when the metanephros or permanent kidney develops, the latter portion degenerates, leaving only a few rudiments, such as the paroophoron in the female (p. 1269) and the vas aberrans and paradidymis (p. 1257) in the male. The reproductive portion also becomes much reduced in the female, persisting as the tubules of the epoophoron (p. 1269), but in the male it
In addition to the Wolffian duct, a second duct, the Miillerian, occurs in connection with the genito-urinary apparatus, and, like the Wolffian duct, it opens below into the cloaca. The history of the two ducts is very different in the two sexes. In the male the Wolffian duct persists to form the vas deferens, of which the seminal vesicle is an outgrowth and the ejaculatory duct the continuation, while the MilUerian duct degenerates, its lower end persisting as the prostatic utriculus and its upper end as the appendix of the epididymis. In the female, on the contrary, it is the Miillerian duct which persists, its lower portion fusing with the duct of the opposite side to form the vagina and uterus, while its upper portion forms the tuba uterina. Inhibition of the fusion of the lower ends of the two Miillerian ducts gives rise to the bihorned or divided uteri, or the bilocular uteri and vaginse which occasionally occur. The Wolffian duct in the female almost completely disappears, persisting only as the longitudinal tube of the epoophoron and as the rudimentary canal of Gartner (p. 1275) . With the degeneration of the mesonephros the peritoneum which covered it becomes a thin fold, having in its free edge the Miillerian duct and, on the fusion of the lower ends of the ducts, the two folds also fuse and so give rise to the broad hgament.
Prostatic utriculus
The development of the external organs of generation in the two sexes presents a similar differentiation from a common condition. The division of the cloaca to form a urogenital sinus and the terminal part of the rectum has already been noted (p. 1253). In the floor of the sinus, to the sides of and above the urethral orifice, erectile tissue develops, forming a genital tubercle. An outpouching of that portion of the anterior abdominal wall to which the round ligament of the uterus or the gubernaculum was attached occurs to form the genital swellings.
of the sinus, enclosing the genital tubercle above and forming the genital folds.
This condition practically represents the arrangement which persists to adult life in the female. The genital tubercle becomes the clitoris, the genital swellings the labia raajora, the genital folds the labia minora, and the urogenital sinus, into which the urethra and Miillerian ducts (vagina) open, is the vestibule. In the male tlie development proceeds farther. The genital tubercle elongates to form the penis, and the free edges of the genital folds meet together and fuse, closing in the urogenital sinus and transforming it into the cavernous portion of the urethra, thus bringing it about that the male urethra subserves both reproductive and urinary functions. The genital swellings also meet and fuse together below the root of the penis, forming the scrotum.
Genital swellings Scrotum Labia majora
Inhibition of the development of the parts in the male or their over-development in the female will produce a condition resembling superficially the normal condition of the opposite sex, and constituting what is termed pseudo-hermaproditism; or a failure of the genital ridges to fuse may result in what is known as hypospadias, the cavernous portion of the urethra being merely a groove in the under surface of the otherwise normal penis.
References for the Urogenital System. A. Urinary tract. {General, incl. literature to 1900) Disse, in von Bardeleben's Handbuch; {Renal blood-vessels) Brodel, Proc. Ass'n Amer. Anatomists, 1901; {Renal tubules) Huber, Amer. Jour. Anat., vol. 4; Peter, Die Nierenkanalchen, etc., Jena, 1909; {Topography of female ureter) Tandler u. Halban, Monatschr. Geburtsh. u. Gynak., Bd. 15. B. Male reproductive tract. {General, incl. literature to 1903) Eberth, in von Bardeleben's Handbuch; {Histology and development) von Lichtenberg, Anat. Hefte, Bd. 31; Hill, Amer. Jour. Anat., vol. 9; {Prostate) Bruhns {lymphatics) Arch. f. Anat. u. Entw., 1904; Ferguson {Stroma) Anat. Rec, vol. 5; Thompson (topography) Jour. Anat. and Physiol., vol. 47; {External genitals) Forster, Zeitschr. f. Morph. u. Anthrop., Bd. 6. C. Female reproductive tract. {General, incl. literature to 1896) Nagel, in von Bardeleben's Handbuch; Waldeyer, Das Becken, Bonn, 1899; {Lymphatics) Bruhns, Arch, f. Anat. u. Entw., 1898; Polano {ovary) Monatschr. Geburtsh. u. Gynak., Bd. 17; {Nerves) Roith, Arch. f. Gynak., Bd. 81; {Histology, ovary) von Winiwarter, Anat. Anz., Bd. 33; {Develop?/ient, uterus) Hegar, Beitr. z. Geburtsh. u. Gynak., Bd. 13; Stratz, Zeitschr. Geburtsh. u. Gynak., Bd. 72; {Lig. eres) Sellheim, Beitr. z. Geburtsh. u. Gynak., Bd. 4, 1901.
THE covering which envelops the whole external surface of the body is known as the common integument [integumentum commune]. This consists of the cutis or skin proper and of appendages, the hair, nails, and skin glands. The cutis is composed of a superficial epithelial layer, the epidermis, derived from the ectoderm, and a deep connective tissue layer developed from the mesoderm and divided into a superficial part, the corium, and a deeper part the tela subcutanea (figs. 1040, 1041). The subcutaneous tela is not usually considered as a part of the skin in a restricted sense, but as a superficial fascia, which name is often applied to it.
Tela Subcutanea
The skin forms an encasement for the entire body broken only in the regions where it merges with the mucous membranes. It serves not only as a direct physical protection to the underlying structures, but also, through its function as an organ of touch and of general sensibility, it indirectly protects the body by the action of the special end organs and peripheral terminations of the sensory nerves which thus bring the body into relations with its surroundings. Through the radiation and conduction of heat to and from the blood circulating in it, through the amount of secretion of its glands and the evaporation from its surface, the skin forms the principal organ for the regulation of the bodily heat. By means of the action of its sweat and sebaceous glands it possesses an important secretory function. It has also a minor role as an organ of respiration and absorption.
The surface area of the skin corresponds approximately to the surface of the body and naturally varies with the size of the individual. It has been variously estimated at from 10,500 to 18,700 sq. cm. for a medium-sized adult male. 81 1281
1282 THE SKIN, MAMMARY GLANDS AND DUCTLESS GLANDS
The aperturae cutis are holes through the skm where it joins with the mucous membrane, usually without sharp line of demarcation, at the nares, the rima oris, the anus, and the external urethra in the male, and at the vaginal vestibule in the female.
Owing to the fact that the skin extends beyond the surface at the aperaturse cutis, and covers the major and minor pudendal labia, and the prepuce and extends into the external acoustic canal, the surface area is slightly greater than the surface of the body.
The thickness of the skin varies in different regions of the body and also in different individuals. The mean thickness is between 1 and 2 mm., the extremes ranging from .3 to 4.0 mm. or more. This is exclusive of the subcutaneous tela. The thickness appears to be in direct proportion to the amount of friction and pressure to which the part is subjected. Thus it is thicker on the dorsal than on the ventral surface of the trunk and neck, and on the flexor than on the extensor surfaces of the hands and feet. Otherwise it is thicker upon the extensor than on the flexor surface of the extremities.
The thickness of the skin is least upon the tympanum and it is also thin upon the eyehds and penis. It obtains a thickness of 3 mm. on the volar surface of hands and plantar surface of the feet and gains a thicliness of about 4 mm. on the cephalic part of the back and dorsal surface of the neck. It is thinner in the aged than in the adult, thicker in men than in women, and in the same sex is subject to much individual variation depending upon exercise, occupation, etc. The vascularity of the skin also influences its thickness.
Over most of the surface of the body the skin is elastic and so loosely attached that it may be stretched to a greater or less extent. The elasticity varies in different individuals. Closely associated with the elasticity is the manner of attachment of the skin to underlying structures. This varies somewhat according to the tissues which are covered but the great motility is due in the main to the very oblique arrangement of the connective tissue and elastic fibres of the deeper layers of the skin; the fixity to the more vertical arrangement of these fibres. An understanding of the looseness and elasticity of the skan is of much practical importance to the surgeon in certain operations.
When the [traction is slow as over a slow-growing tumour, or over the abdomen and breasts in pregnancy, the skin may be stretched to a very considerable degree. In these cases there are often produced short parallel reddish streaks which when the stretching is reheved are re-
placed by whitish, silvery lines, striae or lineae albicantes, due to atrophy of the tissues. In spite of this the skin usually retains enough elasticity to contract gradually to its former extent as it does immediately after moderate stretching.
In most parts of the body the attachment is loose so that the skin is movable and may be pinched up into folds. In some places the attachment of the skin is firm and there is no slipping of the skin over underlying parts, as on the glans penis. In some other parts the motion is very limited as in the scalp and the volar surface of the hands and the plantar surface of the feet.
The colour of the skin varies greatly. It may be white, yellow, black, red, or any of the shades of these colours, and, according to the colour, the races of manIdnd have been roughly divided. The colouration is due partly to pigment and partly to the blood within the cutaneous vessels. The amount of pigment varies with race, age, sex, and with exposure to the sun and air. In the white races the skin of the child is a pinkish white, tending to become dead white in the adult and yellowish in the aged, and it is normally more pigmented in certain regions, such as the axillary region, the scrotum, the vulva, and the mammary areola.
The colour of the white, yellow, red, and black races is not produced by the climate, as we find different races existing under the same climatic conditions and the same coloured race under different conditions of climate. Each race presents several variations of colour; for example, in the white race we distinguish a blonde, a brimette, and an intermediate tj'pe. Anthropologists distinguish twenty to thirty different shades of colour in the skin. In blondes of the white race under the action of strong sun light the skin passes from a rose white to a brick red or becomes pigmented in spots, freckles. In the first case the pigment in the skin is not increased to any great extent but the skin is affected by a superficial inflammation, erythema, associated with exfoliation and often with the formation of blisters. In brunettes of the white race the sun burns the skin a dark yellowish or reddish brown, the degree of pigmentation here being increased and is spoken of as tan. The colouration is onlj' temporary and diminishes on withdrawal from exposure. The sun darkens the skin in the yellow races also. In the newborn of the black races the skin is of a reddish colour, since the pigment although developed to some extent is at birth obscured by overlying opaque cells which later become transparent. The newborn of the yellow races are also hghter than their parents. In white races the shade of the skin is clearer on the ventral surface of the trimk and on the flexor surface of the extremities. In the black races the volar surface of the hands and the plantar surface of the feet as well as the sides of the digits are less deeply pigmented than the rest of the body. The colour of the skin is greatly influenced by the blood in its deeper layers which during life gives it a more or less distinctly reddish tinge, varying directly with the vascularity and inversely with the thickness of the epidermis. Absence
derma. It may affect all the skin structures or it may be partial.
The skin presents certain elevations and depressions due to the fact that it follows more or less closely the contour of the underlying structures, but in addition to this it possesses certain elevations and depressions peculiarly its own. They are found on the skin in various parts of the body. Some are permanent, others only temporary. The most marked depression is the umbilical fovea. Other conspicuous folds and furrows are seen in the neighbourhood of the lips and eyelids. Certain other less permanent folds and furrows are produced by the action of the joints, joint-furrows, and of the muscles of expression of the skin,*'wrinkles."
Other minute folds and furrows which affect only the epidermis and the superficial layer of the corium are seen in various places. These are represented by the numerous fine superficial creases, unassociated with elevations, forming rhomboidal and triangular figures over almost the whole of the surface of the skin (figs. 1042, 1043). They are especially numerous on the dorsal surface of the hands (fig. 1044). The fine curvilinear ridges [cristse cutis] with intervening furrows [sulci cutis] arranged in parallel lines in groups on the flexor surface of the hands and feet are also of this type. They form patterns characteristic for each individual and permanent throughout life.
Fig. 1045. — From a Photograph op the Skin Ridges and Papillae op the Palm op the Hand. Epithelium Completely Removed Above; Partly Removed Below. Of a somewhat different sort are the touch pads (toruli tactiles] of the hands and feet. Among the larger depressions in addition to the umbilical fovea, is the coccygeal foveola, and a considerable num))er of well-marked permanent furrows found in various places, such as the nasolabial and mentolabial sulci, the philtrum labii superioris, the infraorbital sulcus, and the infra- and supraorbitial palpebral sulci. There are numerous articular furrows on both the flexor and extensor surfaces produced by the action of the joints, and associated with intervening folds of skin, particularly on the dorsal surface. They are especially noticeable on the hands. Variations of the palmar joint sulci are due to variations in opposition of the thumb and the use of the fingers and the relative arrangement of the thumb and fingers and joints. They are of
The folds and furrows brought about through the action of the skin muscles run at right angles to the muscle fibres and are more or less transitory at first but become more permanent through repeated or long-continued action. They are represented by the wrinkles of the forehead, the lines of expression of the face, the transverse wrinkles of the scrotum and the radiating folds around the anus. The more superficial cristae cutis and sulci cutis are arranged in groups within and around the touch pads, on the volar surface of the hands and the plantar surface of the feet (figs. 1042, 1043). The crista; of each group are parallel. They correspond to the rows of papillfe of the corium.
Because the patterns of the crista; and sulci are characteristic for the individual, and permanent from youth to old age, they have been classified in a number of types and are important medioolegally as a means of identification. The various systems of classification are based upon the arrangement over the distal phalanges of the fingers and make use of (1) a transverse ridge which is parallel with the articular plicae (2) a curved ridge with its convexity distally and more or less closely meeting the first, medially and laterally, and (3) the curved and concentric ridges between these two (fig. 1043).
A complex wrinkling of the skin appears in old age, or in the course of exhausting diseases/as a result of loss of elasticity and from absorption of the cutaneous and subcutaneous fat. Rounded depressions called dimples are produced by the attachment of muscle-fibres to the deep surface of the skin, as on the chin and cheek, and are made more evident by the contraction of these fibres. Others are produced by the attachment of the skin by fibrous bands to bony eminences, as the elbow, shoulder, vertebrse, and posterior iliac spines. They are best seen when the subcutaneous adipose tissue is well developed.
The cutis is made up of two layers which are structurally and developmentally markedly different. The superficial ectodermic portion, epidermis, is made up almost entirely of closely packed epithelial cells, the deeper mesodermic part, corium, is formed largely of connective-tissue fibres.
The epidermis (cuticle, scarf-skin) is a cellular non-vascular membrane which forms the whole of the superficial layer of the skin and at the great openings through the skin, as the mouth and anus, blends gradually with the mucous membrane. It represents from one-tenth to over half the thickness of the skin, in different parts of the body, the usual thickness being .05 to .2 mm., ranging from .03 mm, to nearly 3 mm. The thickness varies also in different individuals. Its deep surface is molded exactly to the underlying corium but its superficial surface fails to reproduce all of the irregularities of the latter. In spite of this close association, blood-vessels never enter the epidermis.
the surface of the corium and joined together by fine fibrils; more superficially they become round or polyhedral. These cells together with several more superficial layers form a stratum from which the other cells of the epidermis are developed and which therefore are laiown as the stratum germinativum (Malpighii). The cells in the superficial part of this stratum, in some situations, have a granular appearance forming a layer which is called the stratum granulosum. Superficial to this there is, also only in some places, a layer in which the cells are somewhat indistinct and transparent, and therefore known as the stratum lucidum. This is a transition between the softer and more opaque stratum germinativum and the firmer and more transparent superficial layer formed of large, flattened, dry, horny cells, known as stratum corneum.
In general the stratum germinativum is thicker than the stratum corneum. In certain parts as the face, the back, the back of the hands and feet, the two layers are equal in thicloiess. In other regions, as in the volar surface of the hands and plantar surface of the feet, the stratum corneum is much thicker than the stratum germinativum varying from two to three or even five times as thick. This increased thickness of the stratum corneum is not due to pressure alone as it is well marked in the foetus, but it is not improbable that pressure may stimulate the further growth of the cells.
Where the papilte of the corium are arranged in rows as on the volar surface of the hands and the plantar surface of the feet, the epidermis is molded to these so as to appear as ridges on the surface, already described as cristse. In most other places the irregularities of the papillae of the corium do not show on the sm-face. At short and regular intervals on the cristse are notches and transverse furrows which mark the openings of the sweat glands.
The separation of the epidermis from the corium by the accumulation of serous fluid between the layers is known as a bUster. Sometimes it is only the separation of the superficial layers from the deeper layers of the epidermis.
The skin is regenerated after a blister or a wound by growth of the cells of the stratum germinativum. It is probable that cells of the superficial layers take no part in this. Therefore in skin grafting the surgeon in order to transplant the cells of the stratum germinativum usually includes all the layers of the epidermis and the extreme tips of the papillae of the corium as shown by the minute bleeding points left on the surface from which the graft has been cut.
The pigment which gives the main colour to the skin is caused by the accumulation of pigment granules, melanin, in the deepest cells of the stratum germinativum. It does not occur until after the sixth month of foetal life and develops chiefly after birth. The blackness of the skin of the negro depends almost entirely upon this pigment. Pigment granules are also found to a less extent in more superficial cells and sometimes in the corium.
Development of the epidermis. — The epidermis is derived from the ectoderm, in early embryos appearing as a double stratum of cells, the superficial layer of which is known as the epitrichium or periderm, the deep layer becomes the stratum germinativum. By multiplication of the deep cells a number of layers are produced and the more superficial cells tend to assume the adult characteristics. At about the sixth month of foetal hfe the epitrichial layer finally disappears. The surface layers are cast off and mixing with the secretion of the cutaneous glands form a yellowish layer over the surface of the skin of the foetus, the vernix caseosa.
Growth continues throughout life. New cells are formed in the deeper layers pushing the older cells toward the surface. The character of the cells changes as they approach the surface, the change being quite abrupt at the level of the stratum lucidum. As the form of the cells changes, chemical and physical alterations of their contents occur. In most places the superficial cells are represented by thin scales but in the palms and soles the cells are somewhat swollen. The superficial cells are being constantly thrown off and replaced by deeper ones.
The corium (cutis, cutis vera, derma) is a fibrous vascular sh.eath composed of interwoven bundles of connective-tissue fibres intermixed with elastic fibres, connective-tissue cells, fat, and scattered unstriped muscle-fibres. It is traversed by rich plexuses of blood-vessels, lymph-vessels, and nerves, and encloses hairbulbs and sebaceous and sudoriferous glands. It varies in thickness from .3 mm. to 3.0 mm. or more, usually ranging from .5 to 1.5 mm. It is to this layer that the strength and elasticity of the skin are due and it is also only this layer which when properly cured we know as leather.
The superficial layer of the corium is of finer, closer texture, free from fat, and forms a multitude of eminences called papillae corii (figs. 1040, 1045, 1046) which project into corresponding depressions on the deep surface of the epidermis. For this reason this part of the corium although but indistinctly separated from the deeper layer is called the corpus papillare.
Some of the papillae contain vessels, others nerves, hence they are known as vascular or tactile papillse. They are very closely set, varying considerably in number in different parts of the body from .36 to 130 to a square millimetre, and it has been estimated that there are about 150 million papilloe on. the whole surface. They also vary greatly in size not only in different regions but in the same region, being from .03 to .2 mm. or more in height.
The deeper layer of the corium, the tunica propria (stratum reticulare), is composed of coarser and less compact bands of fibrous tissue intermingled with small fat lobules. The fibrous and elastic tissue is arranged for the most part in intercrossing bundles nearly parallel to the surface of the skin.
different parts of the body. In general those are best developed which have a direction parallel with the usual lines of tension of the slcin, hence it results that wounds of the skin tend to gape most at right angles to these lines. The bundles take a direction nearly at right angles to the long axis of the hmbs, and on the trunk run obhquely, caudally, and laterally from the spine (figs. 1047, 1048). On the scalp, forehead, chin, and epigastrium, equally strong bundles cross in all directions, and a round wound, instead of being linear as elsewhere, appears as a ragged or triangular hole. The arrangement of the connective-tissue bundles influences the arrangement of the blood-vessels of the skin.
The tela subcutanea or superficial fascia is also a fibrous vascular layer which passes as a gradual transition without definite line of demarcation from the deep surface of the tunica propria of the corium to connect it with the underlying structures.
Like the tunica propria it is composed of bundles of connective tissue containing elastic fibres and fat, but the bundles are larger and more loosely arranged, and form more distinct cormeotive-tissue septa, which divide the fat, when present, into smaller and larger lobules. Where these connecting strands are especially large and well defined, they are known as retinacula. Over almost the whole surface of the body the connective-tissue strands of the tela
are arranged nearly parallel with the surface, and bind the skin so loosely to the parts beneath that it may stretch and move freely over the deeper parts. In some situations the connectivetissue bundles of the tela subcutanea run almost at right angles to the surface and bind the skin firmly to the deep fascia, as in the flexor surface of the hands and feet and in the scalp and face.
The quantity of subcutaneous fat varies considerably in different parts of the body. It is, for instance, entirely absent in the penis, scrotum, and eyeUds. When it is abundant, the subcutaneous layer is known as the panniculus adiposus.
In some situations, as in the caudal portion of the abdomen and in the perineum, the connective tissue is so arranged that the panniculus may be divided into layers, so that a superficial and a deep layer of the superficial fascia may be recognised. The fat is well developed over the nates, volar surface of the hands and plantar surface of the feet, where it serves as pads or cushions; in the scalp it appears as a single uniform lobulated layer between the corium and the aponeurosis of the epicranial muscle; and on other parts of the surface it is somewhat unequally distributed and shows a tendency to accumulate in apparent disproportion in some localities, as on the abdomen, over the symphysis pubis, about the mammse in females, etc. Everywhere except on the scalp it may undergo rapid and visible increase or decrease under the influence of change of nutrition.
The amount of elastic tissue mixed with the white fibrous connective tissue of which the corium and subcutaneous tela mainly consist varies in the different parts of the body. It is especially abundant in the deeper layer of the tela over the caudal part of the ventral abdominal wall where it forms almost a continuous sheet. Many elastic fibres also accompany the blood-vessels and are mingled with the connective-tissue sheaths around the hairs, the sweat glands, and their ducts.
The papillce corii are usually simple cones but some are bulbous at their ends and others have duplicated apices. They may be perpendicular to the surface or oblique, in some places overlapping. Those on the flexor surfaces of the hands and feet are best developed and are arranged in rows so as to form long parallel curvilinear ridges, two of which are grouped together and correspond to one crista on the surface of the epidermis (figs. 1045, 1046). When there are no papillary ridges the papilte are irregularly scattered, shorter, and may disappear in places or be replaced by ridges. The papilliE serve to give a greater surface area to the corium so as to bring a greater number of blood-vessels and nerves into closer relation with the epidermis and thus with the surface of the body. They are best developed where the epidermis is thickest. Thus they are the largest on the flexor surface of the hands and feet and beneath the nails and are smallest on the face, scrotum, and mammEe.
The skin, as removed in the dissecting room, usually includes the epidermis and more or less of the corium and subcutaneous tela. The cut surface is formed of connective tissue which has a shining bluish-white appearance with minute pits closely scattered over the surface.
unstriated muscle.
Subcutaneous planes of striated muscle are relatively scanty in man when compared with the great panniculus carnosus of the lower mammalia. This is mainly represented by the platysma in the neck which has both its origin and part of its insertion in the skin. Closely associated with this are the muscles of expression of the face and the palmaris brevis muscle which have one end terminating in the deep surface of the skin. The epicranial muscle is also considered by some to belong to this group.
Unstriated muscle fibres are scattered through the corium collected into bundles in the neighbourhood of the sebaceous glands and the hairs. They are described in connection with these latter (p. 1293). In addition to these unstriated muscles are found in the scrotum as the dartos, in the perineum, around the anus, and beneath the papilla and areola of the mammary gland.
Burssa mucosae subcutanea. — In some situations where the integument is exposed to repeated friction over subjacent bones or other hard structures its movements are facilitated by the development of sac-like interspaces in the subcutaneous tissue, the subcutaneous mucous bursse. They are similar to the more deeply placed bursse which are found in relation with muscle tendons. Their occurrence is quite variable. In some individuals they are numerous, in others very few. They have a considerable practical importance from the fact that they may become greatly swollen.
The most constant subcutaneous mucous bursae are the following:
Bursa anguli mandibulae; B. subcutanea prementalis, between the periosteum and soft parts over the tip of the chin; B. subcutanea prominentise laryngese over the ventral prominence of the thyreoid cartilage of the larynx (often found in the male; B. subcutanea acromialis, between the acromion and the skin; B. subcutanea olecrani, beneath the skin on the dorsal surface of the olecranon; B. subcutanea epicondyli humeri lateralis, found beneath the skin over the lateral epioondyle of the humerus (occasional); B. subcutanea epicondyli humeri medialis, between the skin and the medial epicondyle of the humerus (more frequent); B. subcutanea metacarpophalangea dorsalis, between the sldn and the dorsal side of the metacarpophalangeal joints (occasional, especially the fifth); B. subcutanea digitorum dorsalis, beneath the skin over the proximal finger-joints; and rarely over the distal finger-joints; B. subcutanea trochanterica, between the skin and the great trochanter of the femur; B. subcutanea praepatellaris, beneath the skin covering the caudal half of the patella; B. subcutanea infrapatellaris, between the skin and the cephahc end of the ligamentum patella;; B. subcutanea tuberositatis tibiae ventral to the tibial tuberosity, covered by skin or by skin and crural fascia; B. subcutanea malleoli lateralis, between the skin and the point of the lateral malleolus; B. subcutanea malleoli medialis, between the skin and medial malleolus; B. subcutanea calcanea, in the sole of the foot between the skin and the plantar surface of the calcaneum; B. subcutanea sacralis, beneath the skin which covers the lumbodorsal fascia and the region between the sacrum and coccyx.
Blood-vessels of the skin. — Both the corium and the subcutaneous tela are very vascular, but the size and number of vessels varies in different situations. Although the origin of the cutaneous arteries from the deep arteries and the positions where the subcutaneous arteries pierce the muscles vary greatly, the areas supplied by certain groups of arteries and the direction in which the arteries of the skin run show much regularity. Moreover the metameric arrangement of the arteries in the skin is clearly seen, especially upon the trunk. We can recognise two groups of skin arteries. One group is represented by a small number of rather large branches which are distributed throughout or principally in the subcutaneous tela and corium, as the inferior superficial epigastric artery, the arteries of the scalp, etc. These arteries tend to
The arteries enter the corium from the subcutaneous tela, break up into smaller branches anastomose freely and in the deepest layer of the corium form a network, the cutaneous rate (subcutaneous plexus), rete arteriosum cutaneum, from which small branches are given off to supply the fat and sweat glands and also to the papillary layer of the corium. Here another network of arteries is formed, the subpapillary rete, rete arteriosum subpapillare. From the subpapillary plexus, minute twigs pass to the papilla;, to the hair follicles, and to the sebaceous and sudoriferous glands.
The cutaneous veins like the arteries may be divided into three groups: (1) small radicals which accompany the corresponding arteries and go to make up veins whose main function is to collect the blood from the muscles; (2) larger branches accompanying the arteries whose main course is in the subcutaneous tela as the inferior superficial epigastric vein; (3) large veins which run in the subcutaneous tela but have a course independent of the arteries such as those seen through the slcin on the hands and arms. These large vessels will be found described in connection with the general description of the veins (Section V).
more distinct than the arterial, may be recognised in some situations. Of these retia venosa one is situated just beneath the papilla;, and another at the junction of the corium and subcutaneous tela. They receive branches from the fat, hair folhcles, and glands, and empty into the large veins of the sldn situated in the subcutaneous tissue.
Lymphatics of the skin. — The cutaneous lymphatic vessels are found in the skin of all parts of the body but are more abundant in certain places. The lymph-vessels of the skin are developmentally among the first lymph-vessels to appear. The larger vessels and glands of the subcutaneous tela will be found described in connection with the general lymphatic system Section VI). In the corium the lymphatics from the papillae form a subpapillary network which opens into a subcutaneous plexus connected with the larger lymph-vessels of the subcutaneous tela. There are no lymph-vessels in the epidermis, but this is supposed to be nourished by the lymph in the tissue spaces between the cells and these spaces connect indirectly with the lymph-vessels.
The nerves. — The skin has one of the richest nerve supplies of the body. The nerves are in greater proportion in those parts which are most sensitive. The various skin areas are supplied by specific (segmental) nerves with much greater regularity than in the case of the arteries. The nerves supplying adjoining areas overlap so that there is an intermediate space supphed by both. The variations consist in an extension of one area and a corresponding contraction of an adjoining area. The distribution of the nerves in the skin shows, especially on the trunk and neck, a marked metameric arrangement. The arrangement of these nerves in the subcutaneous tela
System.
With the exception of the nerves to the sudoriferous and sebaceous glands, the skin-muscles and blood-vessels, all the cutaneous nerves are sensory. They have diverse modes of termination. Some end in the subcutaneous tela; others, the greater number, terminate in the corium; still others extend to the epidermis.
Toward their termination the nerves branch and rebranch, and just beneath the surface they form a great number of small twigs from which the terminal fibres arise. These may be divided into two groups, those that end freely and those whose termination is surrounded by a capsule. The free ends are slightly enlarged and terminate in the epidermis and in certain regions in the corium. The encapsulated terminations form special end organs and are found in the corium as the bulbous corpuscles (end-bulbs of Krause) [corpuscula bulboidea, Krauserii]; the tactile corpuscles (corpuscles of Meissner or Wagner) [corpuscula tactus, MeissneriJ; and the genital corpuscles [corpuscula nervorum genitalia[. In the subcutaneous tela the end-bulbs are seen as the lamellous corpuscles (corpuscles of Vater: Pacinian corpuscles), [corpuscula lamellosa; Vateri, Pacini[ shown in fig. 1049; the Golgi-Mazzoni corpuscles and the Rufflni corpuscles. All the terminations except the lamellous corpuscles are microscopic, not exceeding 0.2 mm. in length. The lamellous corpuscles, which are readily seen in reflecting the skin from the fingers and toes, may be as much as 2 mm. long and half as thick (fig. 1049). The exact function of each of the various endings is not known. They are undoubtedly sensory fibres except those to the glands, muscles, and blood-vessels.
Development of the corium and subcutaneous tela. — The corium is developed from the superficial part of the myotome or dermo-muscular plate of mesoderm. At first it is very largely cellular but later fibres are produced. In the earlier stages the corium and tela subcutanea are not distinguishable and only in the later embryonic period may the corium be separated into the papillary stratum and the tunica propria.
The hairs [pili] are less developed in man than in any other primate. Where well developed they in themselves serve as a protective organ and moreover through their connection with the nervous system they become in a measure organs of special sense. They are strong, flexible, somewhat elastic, and poor conductors of heat. They cover the entire surface of the body with the following exceptions: The flexor surfaces of the hands and feet; the dorsal bends and sides of the fingers and toes; the dorsal surfaces of the distal phalanges of the fingers and toes; the red borders of the lips; the glands and inner surface of the prepuce of the penis and clitoris; the inner surface of the labia majora; the labia minora and the papilla mammae.
The size and length of hairs varies greatly not only in different parts of the body but also in different individuals and races. In certain situations the hairs are especially long and large and are designated by special names.
Thus upon the scalp, capilli, in the axillary region, hirci, and after puberty upon the face in the male, the beard, barba, and in the pubic region in both sexes, pubes. The pubic hairs extend upon the external genital organs and upon the ventral abdominal wall toward the umbilicus. All of the hairs of these regions are not long and large but short and finer hairs are mixed with them in varying numbers. Strong, well-developed short hairs are found in connection with the organs of sense forming the eyebrows, supercilia, the eyelashes, cilia, at the entrance to the external acoustic meatus, tragi, and at the nares, vibrissse. Upon the extensor surfaces of the extremities, upon the chest, and in other situations in some individuals, especially in adult males, the hairs are also longer and stronger than upon the rest of the body, where they are, as a rule, short, fine and downy. The first hairs appearing in the foetus are very fine, and are called lanugo. The long hairs of the adult scalp may attain a length of ISO cm. or more; the short hairs average from .5 to 1.3 cm. in length, while the lanugo does not exceed 1.4 cm.
Excess of long hairs, hypertrichosis, may involve the whole hairy surface of the body. It is usually inherited and affects several individuals in the same family. Local areas of long hairs also occur as over naevi and upon the sacrum. Local congestion due to inflammation, irritation, or pressure may cause hypertrichosis. It is also not uncommon after the menopause.
In diameter the hairs vary from .005 mm. for the finest lanugo to .203 mm. for the coarsest hair of the beard ; but they usually taper toward the tip and also are narrower toward the base. As a general rule, blonde hairs are the finest and black hairs the coarsest.
In colour the hairs may be either blonde, brown, black, red, or some gradation of these colours. The colour varies with the race, and also with the individual, and according to age. It is due to pigment in the cells of the hair but is also influenced by the amount of air between the cells.
Greying and whitening of the hair is due not only to a decrease of pigment but also to an increase in the amount of air between the cells. Sudden blanching of the hair is thought to be due almost entirely to an increase in the quantity of this contained air. Whitening of the hair is physiological in old age and not infrequent in younger persons. This may be an inherited peculiarity or may follow mental overwork, nervous shock, or prolonged disease. Local blanching is also seen as the result of disease.
The hair may be straight, waved, curled, or frizzled in varying degree. Here also there is not only an individual but also a racial variation, as instanced in the curled or crinkled hair of the African negro and the straight hair of the American Indian. The curliness is caused by the form and the manner of implantation in the skin. Straight hairs are round or oval in transection
for its curliuess.
The hairs are arranged singly or in groups of from two to five and, except those of the eyelashes, are implanted at oblique angles to the surface of the skin. The directions in which the hairs point are constant throughout life for the same individual. They are arranged in tracts in which the hairs diverge from a centre in whorls, the vortices pilorum.
These vortices are found oonstantty in certain definite regions and apportion the whole hairy surface. The centres of vortices are found at the vertex (sometimes double) upon the face, around the external auditory meatus, in the axilla, in the inguinal region, and sometimes on the lateral surface of the body. These are all paired except as a rule the first. Where adjoining vortices come together the hairs are arranged in lines along which they all point in nearly the same direction, only slightly diverging, forming the hair streams, fiumina pilorum. In other lines and places the hairs point in converging directions such as at the umbihcus and over the tip of the coccyx.
the same situation with the individual and with differences in race, colour and diameters.
The hairs are most numerous on the head, ranging from 170 to 300 to the square centimetre at the vertex. They are less numerous on other parts of the body, varying from 23 to 44 (per square centimetre) on the chin, and from 24 to 80 on the forearm. The greatest number is found with blonde hair, the next with brown, then black, and the least with red hair.
The structure of the hair. — Each hair consists of a shaft [scapus pili] (fig. 1050) projecting from the free surface of the skin to end (unless broken or cut) in a conical end [apex pih], and of a root [radix pili], imbedded in the case of the lanugo hair in the corium and of the larger hairs at various depths in the subcutaneous tela. Surrounding the root is a downgrowth of the skin known as the follicle [folliculus pili].
The root of the hair at its deepest parts swells to from one and one-half to three times the diameter of the shaft forming thus the bulb [bulbus pili] (fig. 1050). The bulb is hollow and a vascular connective-tissue process, the hair papilla [papilla pili] (figs. 1050, 1051) extends from the deepest part of the follicle into the cavity in its base. The follicle consists of an external connective-tissue portion formed by the corium, the theca folliculi and an internal epithelial portion belonging to the epidermis and divided into two portions, the inner and outer root sheaths (fig. 1050).
The theca of the follicle is composed of an outer loose longitudinal and a middle circular layer of connective tissue and an inner basement membrane. The outer root sheath is directly connected with the stratum germinativum of the epidermis. In its deeper part it consists of several layers of cells but of only one near the surface. The inner root sheath has been divided into three layers. At the junction of the outer and middle thirds of the follicle of most of the hairs, the ducts of usually two or more sebaceous glands connect with the space between the hair
The hair is formed of epithelial cells arranged in two and sometimes three layers; an outer single-celled layer of transparent over-lapping cells, the cuticle, an intermediate layer several cells thick formed of irregular fusiform horny cells containing pigment and arranged in fibrous strands, the substantia corticalis, and in some of the larger hairs an internal two or three celled layer of angular cells occupying the center of the hair shaft for only part of its length, the substantia meduUaris. Between both the cortical and medullary cells are spaces containing air. In the hair bulb, where the cells are larger and softer the layers are not distinguishable. The cells here being in process of division and being gradually transformed into the horny cells of the shaft.
Many of the hairs have in connection with their follicle round or flat bundles of unstriped muscle fibres, the arrectores pilorum (figs. 1050, 1052). These are situated on the side toward which the hairs point, their deep ends being attached to the hair follicle beneath the sebaceous glands which they more or less embrace and their superficial ends connected with the papillary layer of the skin. Contraction of the arrectores not only causes the hairs to become more erect and the skin around them to project somewhat causing "goose flesh, " but also compresses the sebaceous glands which are situated between the follicle and muscle and helps to empty the glands of their secretion.
root sheath.
Development. — The hairs are developed from the epidermis by thickenings and downgrowths into the corium of plugs of epithelium. The deepest parts of these plugs become swollen to form bulbs and from these the hairs are produced. The central cells of the epithehal downgrowths disintegrate producing the lumen of the follicle. The hairs continue to grow from the deeper cells and protrude from their follicles between the fifth and seventh foetal months. Abnormally they may be scanty at birth and rarely entirely absent, alopecia. The lanugo hairs which cover all the hairy parts of the body at birth are soon shed and replaced by new hairs inthe old follicles. Throughout lite also the hairs are being constantly shed and replaced by new ones. This is accompanied by cornification of the bulb and fibrillation of the deep end of the hair (fig. 1051). Thinning of the hair and baldness occur when the shed hairs cease to be replaced. This is common in old age and a premature baldness appears to run in certain families. The rate of growth is normally from 1 to 1.5 cm. per month, but is subject to variation.
B. THE NAILS
The nails [ungues] are thin, semi-transparent, horny epidermic plates upon the dorsal surfaces of the distal phalanges of the fingers and toes. Through their hardness they serve as protective organs not only by covering the nerve endings and other delicate structures of the skin; but also by acting as natural weapons. On the fingers they form useful tools. They are four-sided plates presenting a dis-
tal free border [margo liber], which overhangs the tips of the fingers, an irregular, sharp proximal edge [margo occultus], and on each side a somewhat thinned border [margo lateralis] (fig. 1053).
Margo occultus
Each nail is composed of an exposed distal part, the body [corpus unguis], and a proximal covered part, the root [radix unguis], (fig. 1053), which ends in the margo occultus. The nail is at a slightly deeper level than the surrounding skin which overhangs the root and the lateral margins in a fold, the nail wall
[vallum unguis] (figs. 1054, 1055, 1056). The epidermis of the free edge of the nail wall, especially proximally, is thickened and often appears as a ragged edge. At a deeper level than the above and extending somewhat more distally is a variably developed thin parchment-like membrane, the eponychium, closely attached to
. Radix unguis
the superficial surface of the nail. It is the representative of the superficial layers of the embryonic epidermis which do not take part in the formation of the nail. The groove which is formed between the vallum and the underlying nail bed is known as the sulcus matricis unguis. This lodges the root and lateral margins
The dorsal free exposed surface of the nail is formed by a hardened, thickened, horny layer of epithelium corresponding to the deeper parts of the stratum corneum (or the stratum lucidum) of the skin, the stratum corneum unguis (fig. 1056). It is convex from side to side (especially on the fifth finger), and also in some cases longitudinally. It presents a number of more or less well-marked fine longitudinal ridges. The stratum corneum forms the principal thickness of the nail. It is thicker and more solid on the toes than on the fingers. The portion of the nail which projects beyond the skin of the fingers and toes is greyish-white in colour. Unless broken or cut, it curves ventrally upon the ball of the finger or toe and tends to become long and claw-like. It may attain a length of 3 or more centimetres.
The concave volar or plantar surface of the nail is softer and is formed of a layer of epithehal cells which corresponds to the stratum germuiativum (Malpgihii) of the skin and is known as the stratum germinativum unguis (fig. 1056). Because of the transparency of both layers of the nail the blood in the underlying matrix is seen through the body of the nail and gives to it a
pinkish colour; but toward the root of the nail there is a semilunar area convex distally, the lunula, which is less transparent and opaque whitish in color (fig. 1053). The lunula is variously developed in different individuals. It is largest on the thumb and is often abssnt on the little finger. It is also smaller on the toes than on the fingers.
The stratum corneum unguis consist of thin, flattened, transparent, horny scales with shrunken nuclei. These cells are intimately joined together in thin layers. The stratum germinativum unguis is formed of cells continuous with and resembling those of the corresponding layer of the epidermis. Air may occur between the cells as with the hair. The cells of the root are not yet cornified or dried out.
The stratum germinativum unguis rests upon the corium, which here forms the so-called nail bed [matrix unguis].' This is made up of a dense feltwork of connective tissue fibres without fat. It is highly vascular and sensitive and the vertically arranged bundles bind the nails tightly to the periosteum of the termmal phalanges. The papillte of the matrix beneath the body of the nail are arranged in stronglj' marked longitudinal ridges, the cristee matricis unguis. The cristffi and papilla; of the matrix fit into corresponding depressions on the deep surface of the stratum germinativum unguis.
The cristse of the matrix are small and low proximally and become larger and fewer distally. Those toward the lateral borders are somewhat oblique. The papillae of the root are not in rows but are irregularly arranged and disappear entirely near the distal border of the lunula. Toward the free border of the nail the papilte become large and change in character to that of the adjacent skin.
of the fifth digits which on the toes are often represented only by a horny tubercle.
Blood-supply of the nails. — The arteries are numerous in the matrix beneath the body of the nail but fewer beneath the root. They pass from the deep parts of the nail bed toward the surface, running in the main longitudinally and sending anastomosing branches to tlie papillte.
Development of the nails. — The nails are developed from the epidermis. In early embryos over the dorsal surface of each distal phalanx there is seen a smoother and more adherent area of skin which becomes Umited by folds distally as well as proximally and laterally. It is also distinguished by a greater number of cell layers which later become flatter than the surrounding cells. The number of cell layers still further increases and at about the fifth foetal month the nail proper is formed by the deeper lying cells over an area extending from the proximal fold to the distal end of the lunula. The nail is pushed distally by constant formation of new cells in the same way as it continues to grow throughout life. The surface epithelial cells of the nail field cover the nail for some time as a thin layer, the eponychium, which later disappears except a small fringe near the root.
Growth of the Nails. — The nail grows in length and thickness by multiplication of those cells of the stratum germinativum which are situated between the margo occultus of the root and the distal border of the lunula. The older cells are pushed distally and toward the surface by the deeper cells. As a result the nail becomes gradually thicker from the occult border as far as the distal margin of the lunula. Over the rest of the nail bed no thickening appears to take place. The rate of growth is faster on the fingers than on the toes and varies with age, season, and the individual. When the nail is torn off, or detached through inflammation, it may be regenerated if the cells of the stratum germinativum have not been destroyed.
Congenital hypertrophy of the nails sometimes occurs, but absence or imperfect development is rarely seen. The white spots so frequently seen in the nail are caused by air between the cell layers due usually to injury or impaired development.
C. THE CUTANEOUS GLANDS
The glands of the skin [glandulae cutis] are of two kinds: glomiform glands, and sebaceous glands. The glomiform ("skein-like") glands [glandulae glomiformes] are of four types: sudoriferous glands, ciliary glands, ceruminous glands and circumanal glands.
The sudoriferous glands [glandulae sudoriferae] or sweat glands are modified simple tubular glands which secrete the siveat [sudor]. They are found in the skin of all parts of the body except that part of the terminal phalanges covered by the nails, the concave surface of the concha of the ear, the labia minora, and the inferior part of the labia majora in the female and the surface of the prepuce and the glans penis in the male. The number found in different parts of the body varies greatly. They are very few on the convex surface of the concha and on
THE CERUMINOUS GLANDS 1297
the eyelid. They are also rather scanty on the dorsal surface of the trunk and neck, more numerous on the ventral surface of these parts and on the extensor surfaces of the extremities, still more numerous on the flexor surfaces, and most numerous on the volar surface of the hands and plantar surface of the feet. They vary from less than 57 to more than 370 to the square centimetre. The total number has been variously estimated at from two to fifteen millions. Each gland (fig. 1057) consists of a secretory portion or body [corpus gl. sudoriferae], and an excretory duct [ductus sudoriferus], which opens on the surface of the skin by a mouth visible to the unaided eye, the so-called 'pore' [porus sudoriferus]. Occasionally the duct opens into a hair follicle.
The bodies of the glands are irregular or flattened spherical masses, yellowish or yellowish red in colour and somewhat transparent. They vary in size from .06 to 4 mm. or more with a mean diameter of .2 to .4 mm., the largest being found in the axilla. They are formed of the irregularly, many times coiled, terminal part of the gland tube. The bodies of the glands are situated in the deeper part of the corium or in the subcutaneous tela.
Enclosing these is a more or less dense connective-tissue sheath. In many of the glands, especially the larger ones, there is a layer of obliquely running unstriped muscle fibres, the so-called myoepithelium, between the basement membrane and the cells. In some cases the bodies of the glands are imbedded in a more or less dense mass of lymphoid tissue.
The ducts, beginning as several coils bound up with those of the bodies, extend often in a straight or sUghtly wavy course nearly at right angles to the surface as far as the epidermis. This they pierce as spiral canals of from two to sixteen turns, more marked where the epidermis is thickest (fig. 1041), and opened on the surface by somewhat widened funnel-shaped mouths. The ducts pass between the papilla? of the corium and open on the summits of the cutaneous cristae where these are present. The diameter of the ducts is distinctly smaller than that of the secreting part of the glands, and this is true of the lumen also.
The ducts are lined by a stratified epithelium composed of two, three, or more layers of cella resting on a basement membrane without any intervening layers of muscle-cells, and surrounded by a connective-tissue sheath. This latter as well as the basement membrane ceases at the epidermis and the epithelial cells of the duct walls join those of the stratum germinativum. The duct for the rest of its course to the surface is merely a canal through the cells of the epidermis.
The degree of development of the sweat glands varies with the situation, the individual, and also racially, as instanced by their great development in the negro. In some individuals the perspiration is much more profuse than in others. The glands are smaller in the aged than in the young. The odour of the sweat is peculiar and more or less characteristic, varying with the individual.
The sudoriferous glands in the axillary region seem to be in some way connected with the sexual function for although a large number persist as small glands, others undergo further development beginning about the ninth year in the female and at puberty in the male. These glands in places form almost a continuous layer and are formed of large partly branched tubules with high secreting cells. The reddish colour of the sweat in the axillary and some other regions, especially in certain individuals, is probably derived from the pigment granules which are found in the glands here. The oil in the secretion lubricates the skin and keeps it soft and supple.
Blood-supply of the sudoriferous glands. — The sudoriferous glands are supplied from the deep cutaneous plexus by an abundant network of arteries which surround and penetrate between the coils of the gland tubules.
the gland cells.
Development. — The sudoriferous glands are seen first in the fourth or fifth foetal month. The anlages resemble closely those of the hair, but the cells are not so loosely packed. They project down as solid plugs which become long, slender, and tortuous rods. In the seventh foetal month the rods begin to develop a lumen in the deeper parts, which also now begin to coil. A lumen soon develops also in the superficial parts and joins that in the deeper part of the gland. The outer of the two layers of epitheUum in the ducts becomes transformed at its transition into the gland proper into the myoepithelial layer.
The ciliary glands [gl. ciliares; Molli] are modified sudoriferous glands of the branched tubo-alveolar type. They have simpler coils but are larger than ordinary sweat glands. They are situated in the eyelids near their free borders and open into the follicles of the cilia or close to them (see Section VIII).
1.5 cm. wide which surrounds the anus, a short distance from it.
These glands are several times the size of the ordinary sweat glands and resemble the glands found in the axilla, their secretion likewise having a strong odour. They are branching tubular glands. The other kinds of glands which are found in this same area are ordinary sweat glands, glands with straight duets, with saccules and secondary alveoli, and tubo-alveolar glands.
They are very abundant on the dorsal and superior part of the acoustic meatus in the region of the cartilaginous part, where in the adult most of them open on the surface of the skin close to hairs. Others open into the hair follicles as they all do in the foetus and child. Their secretion, the cerumen, is, when freshly secreted, a fluid or semifluid oily material of a yellowish-brown colour, which on exposure to the air becomes solid like wax.
The sebaceous glands [gl. sebaceae] are simple branched or unbranched alveolar glands distributed over nearly the whole surface of the body. Ninetenths of them are closely associated with the hairs, into the follicles of which they empty (figs. 1050, 1051), and are therefore absent from certain of the nonhairy parts of the body, as the flexor surfaces of the hands and feet, the dorsal surfaces of the distal phalanges of the fingers and toes. On the other hand, a few are found, usually much modified, opening independent of the hair follicles, as at the angles of the red margins of the lips, around the nares, around the anus, and the tarsal (Meibomian) glands in the eyelids. Modified sebaceous glands are also found upon the mammary papilla and areola in the female, and in some cases upon the superficial surface of the glans and the surface of the prepuce of the penis, here known as preputial glands ; also a few very small ones may be found upon the labia minora, the glans and prepuce of the clitoris.
The glands vary in size in different situations and also in individuals and races. They range from .2 to 2.2 mm. long and nearly as broad. Among the smallest are those of the scalp. The largest are found on the alse of the nose and on the cheeks where their ducts are visible to the unaided eye. They are also large on the mons pubis, labia majora, scrotum, about the anus and on the mammary areola. Smaller glands are also found associated with these large ones. The size of the glands is independent of the size of the hairs with which they are associated but the number of glands depends upon the size of the hair. On small hairs one or more glands are always found and on large hairs there may be a whole wreath of from four to six separate glands opening into the hair follicle.
The number of sebaceous glands has never been exactly estimated, although, it is known that they are less numerous than the sudoriferous glands. This is very evident on the extremities, trunk, and neck, where they bear a relation of 1 to 6 or 8. On the scalp, concha of the ear, and skin of the face they are about equal in number while on the forehead, alae of the nose, free borders of the eyehds and external genital organs in the female the number of sebaceous glands is greater than the number of sudoriferous glands.
Each sebaceous gland consists of a secretory portion, the body, connected with the hair follicle or the surface of the skin by a wide short duct. In the small glands, the body of the gland may consist of a single alveolus but in the larger glands there are from four to twenty of these connected by irregular ducts to a single excretory duct.
The ducts open into the hair follicles near their necks between the inner root sheath and the hair or upon the surface of the skin. They are always very short, cylindrical, or infimdibuliform, and their epithelium is directly connected with that of the outer root sheath of the hau' folhcle or with the epidermis where the hair is wanting.
The glands lie in the superficial layers of the corium and where one or a few are connected to a single hair, they usually open into the hair follicles on the side toward which the hairs point. Where there are several glands for one hair they may completely surround the hairs like a rosette.
coverings of the hair folhcle.
The periphery of the alveolus is formed of small cubical epithehal cells, the central part of larger and more rounded cells. The cells of the alveolus show all stages of fatty degeneration, the peripheral cells contain small fatty particles, those nearest the centre larger and more numerous fat droplets, some of them being completely broken down. There is no distinct lumen to the alveolus but this is filled with degenerated cells, fatty particles and ddbris of broken-down and cast-off cells. The deeper cells continue to multiply and push the more superficial cells toward the lumen where they in turn are cast off. The secretion thus formed is known as the sebum cutaneum. Through the decomposition of its fat more or less odour is produced. When the gland duct is blocked the secretion is retained and becomes more solid and is known as a comedo. The active secretion of the sebaceous glands does not begin before the fifth or sixth year of life. It attains its maximum in the adult and decreases in the aged.
nection with the relation of these muscles to the hairs.
Vessels and nerves. — The sebaceous glands are surrounded by a fine capillary plexus of blood-vessels closely associated with those of the hairs and skin. Concerning their lymphvessels little is known. The nerves of the sebaceous glands are connected with those of the skin and hair but the exact manner of distribution is not clearly understood.]
Development. — The sebaceous glands appear lirst in the fifth foetal month as single, rarely double, buds on the anlages of the hair follicles. The distal ends of these enlarge and become lobulated. In these solid masses of cells lumina for the alveoli and the ducts later are formed, through the fatty degeneration of the central cells. The oily contents of these cells together with the debris and the cast-off surface cells of the epidermis form the vernix caseosa on the surface of.the foetus.
The mammary glands [mammae] or breasts are modified cutaneous glands. In tlie male they remain rudimentary and functionless throughout life, but in the female they are functionally closely associated with the reproductive organs since they secrete the milk for the nourishment of the newborn and are subjected to marked changes at puberty, throughout pregnancy, during and after lactation, and after the menopause.
Areola
The two mammffi (fig. 1058) are situated on the ventral surface of the thorax one on each side of the sternum. As examined from the surface in a well-developed nulliparous female they appear to extend from the second or third rib to the si.xth or seventh costal cartilage and from the lateral border of the sternum to beyond the ventral folds of the axillse. Separating the two mammae there is a median unraised area of variable size, the sinus mammarum.
In shape they are conical or hemispherical, and in consistency somewhat firm and elastic: The size of the two breasts is seldom equal, the left, as a rule being slightly the larger. Each measures from 10 to 13 cm. in diameter being slightly longer in the direction parallel to the lateral border of the pectoralis major muscle. The weight of each gland varies from 140 to 200 grams, or more.
will be described separately later.
The dorsal surface of the mammary gland (figs. 1060, 1061) is attached and concave. It is in relation in its cephalo-medial two-thirds with the fsacia over the pectoralis major muscle. In its caudo-lateral third it extends over the base of the axillary fossa, where it is in relation with lymphatic glands and with the serratus anterior muscle, and at its most caudal part, sometimes with the external abdominal oblique muscle.
The usual number of breasts in the human species is two; rarely is the number reduced, much more often do we find an increase in this number. Each of these conditions is found in both sexes and may be complete or partial. Complete suppression of both breasts, amastia, is one of the rarest anomaUes and is usually associated with other defects. Complete absence of one is less rare. A more frequent condition is arrest of development, micromastia, leading to rudimentary but functionless organs. Absence of the nipple, athelia, is much commoner and generally affects both breasts. All grades of the imperfection from complete absence to shghtly imperfect nipple may be found. When there is an increase this may include the whole breast, polymastia, or just the nipple, polythelia. The supernumerary structures [mammae
accessori8e] may be represented only bj' a pigmented area representing an areola; or by a nipple with or without an areola; by a gland with a more or less perfect nipple and areola; or with ducts opening without a nipple; or there may be no opening on the surface. The extra mamma is very rarely perfectly developed and functional. Various observers have found the supernumerary breasts or nipples occurring in from 1 to 7 per cent, of the cases examined and somewhat oftener in males than in females. The extra organs are found more frequently on the left side, usually along a line extending from the axilla toward the genitalia. Tliis corresponds to the position in which the mammae occur m some other mammals and also to the milk line of the embryo. Although they are occasionally found in other situations, over 90 per cent, of them are encountered upon the ventral surface of the thorax along the above-mentioned line caudal and medial to the normal pair of breasts. They are frequently hereditary. It is doubtful whether their possessors are either more fertile or more Uable to bear twins.
The shape of the breasts varies with the development and functional activity'and the amount of fat. The smooth, somewhat conical breast of the nullipara becomes hemispherical with increase in the amount of fat, while in emaciation it may be reduced to a flattened disc with an irregular surface. After lactation the breasts tend to become more pendulous with marked sulci between them and the thoracic walls, and after repeated pregnancies they may become elongated so as to be almost conical or even have pedunculated bases.
The size of the mammary gland in girls remains relatively the same as in the infant up to puberty when it suddenly increases considerably and continues for a time to enlarge slightly at each menstrual period. There is also a temporary enlargement and soreness at each menstrual period, due perhaps to the increased vascular supply. Until the age of puberty the glands measure 8 to 10 mm. in diameter but when they have attained their complete adult development they have increased to 100 to 110 mm. in the cephalo-medial, 120 to 130 mm. in the cephalo-lateral (obliquely from above downward) direction, and 50 to 60 mm. in thickness. During pregnancy the breasts again increase in size, more especially
after the birth of the child. When their full functional activity is established, their volume may be two or three times as great as before pregnancy. After lactation they return again nearly to their former size, which they retain until another pregnancy. After the menopause the useless glands in some cases atrophy and are reduced to small discoidal masses. In others, especially in fat individuals, although the secreting tissue disappears, it is replaced by fat so that there is little or no reduction in size. In addition to the above-mentioned variations in size, the breasts are subject to great individual differences, the cause of which is little understood. Large robust women are sometimes seen with small mammary glands, and small women with large glands. In some individuals they are especially large.
The weight of each mamma varies, naturally, with the volume, increasing from 30 to 60 centigrams in the small gland of a young child to 140 to 200 grams after puberty and in nursing women reaching 400 to 500 and occasionally 800 to 900 grams.
The firm and elastic, well-developed breasts of young nullipara become during lactation even more firm and tense, but after lactation especially if there has been a long period of nursing they lose their consistency and after several pregnancies become soft and flabby.
The sulcus which defines the caudal border of the breast is but little marked in thin nullipara, more marked in fat women, and especially evident in some multipara. The relations of the dorsal surface of the gland vary somewhat with the position. The level varies with the stature; as a rule, in tall women it is more caudal and in short and broad-chested women it is more cephalic. The tightness of the attachment to the sheath of the pectoralis major muscle is quite variable, but even when quite loose there is some movement of the breast when the arm is raised. The glandular tissue of that part of the breast which overhangs the axilla may be in direct contact with the lymphatic glands.
Structure. — The mammary glands are composed of the essential epithelial glandular tissue, the parenchyma, the supporting and enclosing connective tissue of the subcutaneous tela, the stroma, and the covering cutaneous layer.
Parenchyma. — The essential part of each mamma is a flattened, circular mass of glandular tissue of a whitish or reddish-white colour, the corpus mammae. This is thickest opposite the nipple and thinner toward the periphery. The ventral surface of this mass is convex and made uneven by numerous irregular pyramidal processes which project toward the skin. The dorsal surface, or base, is flat or slightly concave and much less irregular than the ventral surface. Minute processes of glandular tissue extend from the corpus mammse into the retromammary tissue, some of them accompanying the septa of the pectoral fascia between the bundles of muscle fibres of the pectoralis major muscle. The circumference of the mamma is thick and well defined, more marked caudally than cephalically, but it presents numerous irregular processes which extend beyond the limits apparent from the surface. One of these especially large and well marked extends cephalolaterally into the axillary fossa, and there are frequently other large but lessmarked projections.
The corpus mammae is not a single structure but is composed of from fifteen to twenty separate lobes [lobi mammse] (fig. 1059). These are larger and smaller irregular flattened pyramidal groups of glandular tissue, with their apices toward the nipple and their bases radiating toward the periphery of the gland.
Each lobe has a single excretory duct [ductus lactiferus] (figs. 1059, 1060, 1061), which opens by a contracted orifice [porus lactiferus] in a depression upon the tip of the nipple. When traced from the pore toward the circumference of the gland, the ducts are seen to run first directly dorsally through the nipple, parallel and close to one another. From the base of the nipple they diverge. Each duct is here visible to the unaided eye and measures from 1.5 to 2.5 mm. in diameter. Beneath the areola its diameter increases for a short distance to from 4 to 9 mm., forming thus a reservoir, the ampulla or sinus lactiferus, in which the secretion may accumulate for a time. Beyond this dilation the duct continues, gradually decreasing in size as it breaks up into smaller and smaller branches, There is no anastomosis between the ducts during their course, although at or beneath the pore two or more ducts may join to have a common opening. They possess no valves but when empty their inner surface is thrown into longitudinal plicse.
The ducts have an external coat of white fibrous connective tissue mixed with circular and longitudinal elastic fibres. They are lined with a simple cuboidal or columnar epithelium, except near the orifice, where it is stratified squamous. External to the lining epithelium there
sudoriparous glands.
Each of the terminal branches of a duct ends in a tubulosaccular, spherical or pyriform alveolus. A number of these alveoli which open into a common branch of the duct, when grouped together and bound up with connective tissue, constitute a lobule of the gland (lobulus mammae). A lobe is made up of all the lobules whose ducts join one common excretory duct.
The alveoli are composed typically of a single layer of epithehal cells enclosed by a basement membrane. This layer is the true secretory epithelium. It consists in the more active gland of granular polyhedral or cuboidal cells which may be so closely placed as to leave almost no lumen to the alveoh. During lactation these cells may be found in different stages of secretory activity, their central ends being filled with minute oil globules and more or less flattened according to the degree of distention of the alveoli. The alveoli and ductules now possess considerable lumina which are filled with the above-mentioned millc globules Uberated from the cells and suspended in a serous fluid also secreted by the cells. TMs constitutes the milk (lac femininum).
Stroma. — The lobes, lobules, and alveoli are completely covered by a connective-tissue sheath too delicate to constitute a distinct capsule. Outside of this the whole gland is embedded in the subcutaneous tela which forms for it a sheath, capsula adiposa mammae. This is particularly well developed on the ventral surface where the fat fills in between the irregularities caused by the lobes and lobules and gives to the surface of the gland its smooth appearance. Within the corpus mammte there is little fat between the lobules in nulhpariB but much more fat is found here in the stroma in multipara;. When the fat is absorbed, as it is during lactation and in emaciation, the lobules stand out much more distinctly. There is however, no fat immediately beneath the areola and nipple. The connective tissue is here loosely arranged and allows free motility of the nipple and also permits the more easy distention of the ducts and sinuses during lactation. The connective-tissue strands, retinacula mammae, which extend from the apices of the glandular processes on the ventral surface of the mamma are connected to the cerium and correspond to the retinacula cutis found in other situations. These are sometimes particularly well developed over the cephaUc part of the mamma and have been called the suspensory ligament of Cooper.
In addition to the axillary process or 'tail' of the gland, a projection is sometimes seen extending toward the sternum and another caudolaterally; also processes extending toward the clavicle and caudomedially have been described. Besides these large projections there are numerous branched interlacing processes which combine into larger and smaller masses on the ventral surface and exist as minute extensions on the dorsal sm'face. In thin women, the parenchyma at the apex of these triangular processes reaches nearly to the surface.
A mammary gland may be made up of a larger amount of stroma and a smaller amount of glandular tissue, or the reverse, and therefore a small breast may fiu-nish more milk than a large one. There is also a variation in different parts of the same breast, one lobe or section may have well-developed lobules while in another they remain almost as at puberty, merely branching ducts.
Changes due to age and functional activity. — At birth the mamma consists mainly of fifteen to twenty slightly branched ducts lined with stratified squamous or columnar epithelium. In spite of the lack of true glandular tissue, within the first few days there may be such rapid cell proliferation that the ducts become distended with cells and detritus. By pressure upon the gland a few drops of this material may be expressed which constitutes the so-called 'witches milk.' From birth until puberty the mamma remains rudimentary, simply keeping pace with the general body growth, but in the female, at puberty, an abrupt change occurs. The tubules grow rapidly into the smTOunding tissue and some acini (alveoli) appear; the stroma and fat are also greatly increased; and the breast becomes rounded and well formed but consists mainly of fatty stroma and ducts, with but a very small number (if any) of true secreting acini. At this time in both boys and girls the breast may become swollen and tender and a milk-hke secretion may be produced similar to that at birth. The great increase in volume during pregnancy and lactation is due to the increase in the size and number of the lobules and acini, and is accompanied by a decrease in the interlobular and intralobular stroma and in the fat, so that the gland feels hard and imeven. The acini appear first in the periphery, thence along the larger ducts toward the centre of the corpus mammte.
The secretion of the gland for the first two or three days after parturition until the free secretion of milk is established is termed the colostrum. It differs from normal milk not only in chemical composition but also in containing larger fat globules and special cells known as colostrum corpuscles.
The decrease of the gland nearly to its original size after lactation is due to an involution of the parenchyma, the acini being reduced to narrow tubules, most of them completely atrophying. With this is associated a development of fat and fibrous stroma. The gland does not, however, regain its virgin appearance but its main mass is looser and more irregular, less distinct, and the peripheral processes larger, while the stroma contains numerous fat-lobules. This causes the breast to be less smooth, fii-m, and elastic, and it tends to become pendulous and form a sulcus where it overhangs its base. With the end of sexual activity the secreting portions of the glands gradually atrophy, finally leaving Uttle more than the ducts. Even these undergo senile atrophj', and the main mass of the gland is represented only by a flattened disc, in which the peripheral processes can scarcely be made out. In fat women there may be little reduction in size, but the breast is here transformed almost entirely into fat.
The skin covering the ventral surface of the breast is very white, covered with lanugo hairs associated with sebaceous glands, and contains many sweat glands of the ordinary type. It is so thin that the subjacent veins are readily seen through it. It is closely adherent to the subjacent fatty layer but its flexibility, elasticity, and motility over the deeper glandular tissue permit much stretching during the enlargement which occurs at the time of lactation. In spite of this, linea albicantes are often produced especially when the breasts have been unusually large. Aside from the above-mentioned particulars, it does not differ from the skin of the adjacent part of the thorax, except over the centre of the breast where it forms the areola and nipple.
The areola mammae (figs. 1058, 1059, 1060, 1061) is covered by a thin, delicate, pigmented skin. The colour in young nulliparae is reddish, the shade varjang with the complexion. During pregnancy the colour darkens, slightly in blondes, but so as to become almost black in marked brunettes.
This pigmentation serves as one of the signs of gestation. After lactation the colour fades, but little pigmentation remaining in blondes, considerable in brunettes. During pregnancythere is sometimes seen extending more or less beyond the areola a less deeply and less uniformly pigmented ring, the secondary areola. In size, the areola is subject to considerable individual variation and is increased in pregnancy.
The surface of the areola is roughened by a number of slight elevations irregularly arranged. These are due to underlying large sebaceous and rudimentary milk glands [gl. areolares; Montgomerii], tubercles of Montgomery. Projections caused by sebaceous glands are also found in the secondary areola. All of these tubercles enlarge greatly during pregnancy and the glands produce a slight secretion which is discharged through ducts that open on their summits. The sweat glands are few but large, and in addition to the lanugo hairs there are usually several well-developed hairs.
The corium of the areola is devoid of fat but contains a well-developed layer of smooth muscle fibres, the fascicles of which intercross in various directions but may be seen to be mainly of two orders, circular and radial. They are continuous with those of the nipple. The circular fibres are most numerous adjacent to the nipple, where they may form a layer nearly 2 mm. in thickness.
The areola varies greatly in size, measuring from 15 to 60 mm. in diameter. There is some confusion in regard to the areolar glands and the tubercles of Montgomery. Some consider the tubercles to be caused by the areolar glands, others consider them caused by the sebaceous glands. Sebaceous glands undoubtedly cause the projections in the secondary areola. The sudoriferous glands of the areola are large and compound tubular glands with a comphcated glomerulus and are considered as transitions between sweat and mammary glands. The sebaceous glands are even more numerous than the sudoriferous and are composed of several lobes. They also have been considered by some as intermediate stages in the formation of mammary glands, but this is improbable. There are ten to fifteen very small areolar glands (though Pinard found an average of but four to each breast), whose structure is essentially identical with that of the principal mammary glands. They have dilations on their ducts and they open on the areola at times in common with a sebaceous gland.
The nipple [papilla mamma] (figs. 1058, 1059, 1060, 1061) in well-developed nulliparae is situated slightly meso-caudal to the centre of the breast and on a level with the fourth rib or fourth intercostal space about 12 cm. from the median line. But its position in reference to the thoracic wall varies greatly with age, individual, and the present and past activity of the gland. The nipple is usually somewhat conical or cylindrical with a rounded fissured tip marked by fifteen to twenty minute depressions into which the lactiferous ducts empty. The average length of the nipple is 10 mm. to 12 mm. The skin is thin, wrinkled, and pigmented like the areola, except over the tip of the nipple where there is no pigment.
The corium of the nipple has many large vascular and nervous papilla; and there is no fat in it. Hairs and sudoriferous glands are absent but sebaceous glands are present in great numbers. Their secretion here and over the areola serves to keep the skin soft and to protect it from the saliva of the nursing infant. In the deeper layers of the corium smooth muscle fibres form a loose stratum continuous with that of the areola. This is made up principally of an external circular layer and to a slight extent by an internal layer whose bundles of fibres are parallel with the milk ducts. Numerous interlacing muscle fibres connected with these layers and mixed with loose connective tissue, and elastic fibres, but no fat, surround the lactiferous ducts as they pass through the axis of the nipple.
The nipple usually does not project from the surface until the third year. It soon becomes conical but does not attain its full size until shortly after puberty. The size of the nipple is variable, ordinarily in proportion to the size of the gland, but large nipples are sometimes found on small breasts and small nipples on large breasts. During pregnancy the nipple increases in
size and becomes more sensitive and more easily erectile. The shape of the nipple in addition to conical or cylindrical may be hemispherical, flattened, discoidal, or slightly pedunculated. Its end may be invagtnated or the entire nipple retracted beneath the surface of the gland and projecting only in response to stimuli.
The circular muscle fibres of the nipple act like those at its base in the areola. By intermittent, rhythmic contractions they tend to empty the lactiferous ducts; by continuous and tight contraction they act as a sphincter. When contracted they also narrow the nipple, make it harder, erect, and more projecting. When the vertical fibres contract they depress the tip of the nipple or they may retract the whole nipple beneath the surface. The muscle of the areola when stimulated puckers the skin toward the nipple causing circular concentric folds in the skin of the areola.
The male mammary gland [mamma virilis]. This develops exactly as with the female. From birth to puberty the glands in the two sexes have a parallel growth and development, but from this time on the glands in the male grow but slightly and reach their full development about the twentieth year.
The corpus mammae in the adult male measures from 1.5 to 2.5 cm. in diametei and .3 to .5 cm. in thickness. It is whitish in colour, tough, and stringy. It is composed of the same number of lobes as in the female but these consist of little more than short ducts with no true acini and may be reduced to mere epitheUal or connective-tissue strands. The areola and nipple are present and pigmented, but the nipple averages only 2 to 5 mm. in height. The areola has a diameter of 2 to 3 cm. and is covered with hairs. The areolar tubercles may be recognised and the areolar muscle is present. The position of the nipple in relation to the chest-wall is more constant than in the female as the breast is less movable. It is seldom beyond the limits of the fourth intercostal space or the two adjacent ribs, and averages 12 cm. from the median line. Occasionally the male breast may hypertrophy on one or both sides, gynecomastia.
Blood-supply. — The main arterial supply to the mammary gland is from mammary rami of perforating branches of the internal mammary artery (p. 567). Usually that from the second or third intercostal space is especially large. Small branches, external mammary rami, are also supplied to the caudal and lateral segments of the breast by the lateral thoracic artery (p. 571 ). Some rami from the thoracoacromial or supreme thoracic arteries (p. 571) may reach the cephalolateral segment of the breast and small twigs, lateral mammary rami, from the anterior branches of the lateral cutaneous rami of the aortic intercostal arteries (p. 589) supply its deep surface.
These vessels anastomose freely and form a wide-meshed network in the stroma of the ventral and dorsal surfaces from which branches proceed around the lobes and lobules and finally form a close network of capillaries around the alveoli. From these, venous capillaries arise and pass in two groups, one deep, accompanying the arteries, the others superficial. These latter extend to the ventral surface of the gland to form a loose network beneath the skin. During lactation these subcutaneous veins show through the sldn as bluish lines, and frequently form a more or less complete circle around the nipple. They connect with the superficial veins of the neck superiorly, with those of the abdomen inferiorly, and with the thoracoepigastric vein laterally. The deep veins carry the blood to larger vessels, which empty into the subclavian, the intercostal, the internal mammary, and the axillary; and the superficial group may connect with the external jugular and femoral veins.
The lymphatics. — The lymphatics of the mammae are extremely numerous, forming rich plexuses and free anastomoses. Their exact origin and distribution are not yet fully understood, but it is clear that there is a rich plexus in the skin of the areola and nipple which empties mainly into a subareolar plexus. Deep lymphatics arise in the spaces around the alveoli in all parts of the gland, and most of these converge toward the nipple where they join the subareolar plexuses. They anastomose freely with the cutaneous lymphatics and many of them empty into the subareolar plexus through large lymph-vessels which run parallel with the lacteal ducts. From the subareolar plexus usually two large lymph-vessels arise and pass toward the axilla to empty into the axillary lymph-glands (p. 719). Other lymphatic vessels of the mammary gland follow the course of the various blood-vessels.
There is usually a third trunk from the cephahc part of the breast and often a fourth from the caudal segment which join with the others to the axillary glands. The lymphatics of the mammary gland also commimicate with the lymphatics of the skin, the ventral chest-wall and those of the deep fascia over the pectoral muscles, as well as the lymphatics of the opposite side. They also empty into the lymphatics which accompany the blood-vessels of this region, and thus communicate with the axillarj', subclavicular, and supraclavicular lymphatic nodes (p. 722). Moreover, those from the medial portion of the gland accompany the branches of the internal mammary artery and empty into the sternal glands along the artery within the thorax. Since cancer of the breast extends and is disseminated through Ij'mphatic channels, their distribution and connections are of great practical importance.
The nerves. — The gland proper receives its nerves laterally from the lateral mammary rami of the anterior rami of the lateral cutaneous branches of the fourth to sixth intercostal nerves and medially from the medial mammary rami of the anterior cutaneous branches of the second to the fourth intercostal nerves. The skin over the breast receives in addition to branches from the above nerves, branches from the supraclavicular nerves of the cervical plexus. It is altogether probable that sympathetic fibres reach the gland but by what course is not yet clear. The nerves are distributed in part to the sliin, in part to the plain muscle of the areola and nipple, some to the blood-vessels, and others to the glandular tissue. The secretion is, however, not entirely controlled by nerves as it is influenced also by hormones from other organs brought to it by the blood.
Development. — In very early embryos the epithelium over an area on the side of the body extending from the fore to the hind limb (or beyond these limits) is seen to be deeper and more cubical, the mammary streak. In this area there is produced by multiplication of cells a ridge, the mammry line or ridge. In spots along this line, corresponding to the relative position of the mammary glands in some mammals and the supernumerary mammse in man, the epithelium thickens. The intervening parts of the line disappear as the spots enlarge to form transient mammary hillocks. In man ordinarily development proceeds in but one of these hillocks on each side. The deep surface of the hillock projects into the corium as the superficial surface flattens out and the mesodermic cells of the corium condense around the ingrowth producing the nipple zone. Rapid proliferation of the deeper cells produces a club-shaped stage from the deeper surface of which small bud-like masses of epithelial cells sprout and extend as solid plugs into the corium. These are the anlages of the true secreting part of tlie gland and the number of buds corresponds to the number of lobes of the future gland. The sprouts extend beyond and beneath the nipple zone and are supported by closely packed connective-tissue cells forming the stroma zone. The epithelial buds continue to grow and branch and a lumen is finally produced in the originally solid plugs. The primary epithelial ingrowth degenerates and ultimately disappears. A cavity is produced in it which later connects with the lumina of the gland ducts. The depressed nipple zone becomes elevated above the surface soon after birth. Further development of the mammary gland has been discussed previously under changes due to age and functional activity (p. 1303).
Under the term ductless glands are included not only certain glandular structures of epithelial origin with a more or less definitely known function and an internal secretion but also certain organs whose function is not definitely known or understood. Of the organs here considered, the function of the thyreoid gland, the parathyreoid glands, the chromaffin system, the medullary portion of the suprarenal glands, and the aortic paraganglia is somewhat definitely known. But the function of the thymus, the spleen, the cortical portion of the superenal glands, the glomus caroticum, and the glomus coccygeum is still in doubt; although probably some, if not all of them, have an internal secretion or at any rate are closely associated with the other glands of internal secretion. The hypophysis and the pineal body are not considered in this connection but will be found described with the brain (pp. 845,848). The lymph-nodes, which may also be considered as ductless glands, are described in Section VI. Many of the true glands, such as the liver, pancreas and sexual glands, have also internal secretions which pass directly into the vascular system as in the ductless glands.
lymphatic system. Its exact function is still in doubt.
Position. — The spleen is situated in the dorsal part of the left cephalic segment of the abdominal cavity so deeply placed against the diaphragm and dorsal to the stomach and colon as to be invisible from the ventral surface of the body when the abdominal cavity is opened. It is mainly in the left hypochondriac region but its deepest and most cephalic part extends also into the epigastric region. It is obliquely placed with its long axis corresponding approximately to the line of the caudal ribs. It tends to become more vertical when the stomach is fully distended but when the stomach is empty and the colon distended it assumes a more horizontal position. Changes in the attitude of the body also cause slight alterations in the situation of the spleen. It moves with the excursions of the diaphragm in expiration and inspiration.
organ in the body. Not only does the size differ in different individuals but it changes greatly with the blood content in the same individual. There is a distinct expansion for a time after each meal and the spleen contracts and expands rythmically.
Extremitas inferior
In the adult it usually measures 10 to 15 cm. in length, 7.5 to 10 cm. in breadth, and 2.5 to 4 cm. in thickness. The weight usually ranges from 150 to 225 gm. At birth it represents from jitg to jjo of the total body weight and this porportion is maintained wuthout much variation until the age of fifty years, when (like the lymphoid organs in general) it begins to diminish
tracted surrounding hollow viscera. When in situ with the stomach distended, its shape may be compared to a blunt spherical wedge with a concave apex and rounded extremities, and possessing therefore three surfaces (fig. 1062); but when the stomach is contracted and the left flexure of the colon distended an additional surface is produced and its shape becomes tetrahedral (fig. 1063). Inter-
mediate forms between these extremes are produced by variations in the degree of distention of stomach and colon. The spleen presents two aspects: lateral or parietal, against the diaphragm; and medial or visceral, toward the abdominal cavity. In its usual wedge form the three surfaces of the spleen are diaphragmatic, gastric, and renal. There are three borders, anterior, posterior, and intermediate; and two extremities, superior and inferior.
The diaphragmatic surface [facies diaphragmatica] is a smooth convex surface with an irregularly oval outline, in the wedge-shaped spleens wider cephalically, but in the tetrahedral-shaped spleens wider caudally. It looks dorsally toward the left and somewhat cephahcally.
impressions upon it.
The gastric surface [facies gastrica] is a semilunar-shaped surface, concave cephalo-caudally and from side to side, wiiich looks ventrally to the right and somewhat caudally (figs. 1062, 1065, 1066). Nearly parallel with the dorsal boundary of this surface is a narrow depression usually formed by a series of pits, as a rule six or eight, which together form the hilus of the spleen [hilus lienis]. In this situation the vessels and nerves enter and leave the spleen, the vein being dorsal.
When the stomach is distended it is in contact with the major part of the gastric surface; the left flexure of the colon forming an impression upon a small area near the caudal extremity and the taU of the pancreas, as a rule, resting against a narrow area dorsal to the hilus or just
Fig. 1066. — Sagittal Section through the Left Side op the Body, Showing the Relations of the Spleen. IX, X, XI, XII, corresponding ribs. 1, Left kidney; 2, spleen; 3, pancreas; 4, splenic vessels; 5, transverse colon; 6, stomach; 7, left lobe of liver; 12, lung; 14, heart; 16, diaphragm. (Testut and Jacob.)
cephalic to the colon. When the stomach is empty and contracted and the colon distended the size of the gastric area is considerably decreased and the relative size of the coUc impression greatly increased so as to form upon the spleen in this situation a colic or basal surface (fig. 1063). The stomach is, however, at all times in contact with some part of the spleen.
The renal surface [facies renalis] the smallest of the three surfaces, shorter as well as narrower than the gastric surface, is an oblong, flat or slightly concave area, which faces dorsally, to the right and slightly caudally. It is in relation with the anterior surface of the left kidney (fig. 1066).
In some cases the cephalic third of the renal surface is also in relation with the anterior surface of the suprarenal gland. It is separated from these latter structures, however, by the renal adipose capsule as well as by the peritoneum. The tail of the pancreas in some cases is in contact with a small area on the ventral part of this surface. In fat individuals these relations are not as intimate as the relations with other organs because of the large amount of suprarenal fat.
The anterior border [margo anterior] is clearly defined, thin, sharp, and more or less convex. It is marked in over 90 per cent, of the cases by one or more transverse or oblique notches, especially in its cephalic part. It is placed between the
The posterior border [margo posterior] is rounded, shorter, and straighter than the anterior border and is notched in less than a third of the cases. It separates the diaphragmatic from the renal surface and is lodged in the angle between the left kidney and the diaphragm (figs. 1062-1065).
gastric from the renal surface.
It may be clearly defined or more or less obscure and often shows a marked tubercle (fig. 1064). When the stomach is contracted and the colon distended this border divides caudally into ventral and dorsal limbs both of which may be well marked or either may be deficient depending on the direction and degree of pressure of surrounding organs. When well marked there is produced at the point where the two limbs diverge a more or less marked projection, the intermediate extremity or angle (fig. 1063).
The superior extremity [extremitas superior], usually larger than the inferior extremity in the wedge-shaped spleens but smaller in the tetrahedral form, is rounded and bent medially. It extends as high as the tenth thoracic vertebra and lies 1 to 2 cm. from the vertebral column.
toward the left and caudally. It is in relation with the phrenicocolic ligament.
When the stomach is contracted and the colon distended the inferior extremity becomes much broader, in extreme cases forming a distinct inferior border ending ventrally in the anterior margin as an anterior extremity and dorsally in the posterior margin as the posterior extremity (fig. 1063).
In the tetrahedral-shaped spleen the additional surface produced by the pressure of the colon is known as the basal or colic surface (fig. 1063). This varies in size reciprocally with the degree of pressure of colon and stomach.
When well developed the cohc surface is concave and is separated from the renal and gastric surfaces by the more or less sliarply defined dorsal and ventral limbs of the intermediate border and separated from the diaphragmatic surface by an inferior margin produced from the broadened inferior extremity. The left flexure of the colon is in contact with the greater part of this surface, but the pancreas also usually hes against it in its cephahc part (fig. 1063).
Peritoneal relations. — The surface of the spleen is completely covered, except for a small area at the hilus, by a peritoneal coat, the tunica serosa. Ventral to the hilus a double layer of peritoneum is prolonged from the spleen to the left side of the greater curvature of the stomach and the left edge of the ventral layer of the great omentum, forming the gastrolienal ligament which contains the short gastric arteries and veins. Dorsally a second double layer of peritoneum extends from the hilus to the ventral surface of the kidney and the caudal surface of the diaphragm forming the phrenicolienal (lienorenal) ligament. This ligament encloses the splenic artery and veins as they pass to and from the spleen. It is also between the two layers of peritoneum of this ligament that the tail of the pancreas reaches the spleen (fig. 1065). Except by these two Hgaments the spleen has normally no attachment to the abdominal wall or to any of the surrounding viscera. The gastroHenal, and more especially the phrenicohenal ligament, serve in a measure to anchor the spleen in its place in the abdominal cavity but in addition to these the spleen is supported by a fold of peritoneum which e.xtends from the left cohc flexure to the parietal peritoneum over the diaphragm, the phrenicocolic ligament. This serves as a shng in which the inferior extremity of the spleen rests. The spleen, however, is held in position in the abdominal cavity mainly by the intraabdominal pressure.
Topography. — The superior extremity of an average-sized spleen is located between the angle and tubercle of the tenth rib on the left side and about 3 to 4 cm. from the median line on a level with the spinous process of the ninth thoracic vertebra. In the majority of cases, it does not extend more than 2 cm. either cephalic or caudal to a transverse plane at the level of the infrasternal notch. The inferior extremity reaches nearly to the midaxillary lioe in the tenth intercostal space and 10 to 15 cm. from the superior extremity. The long axis therefore corresponds nearly to the shaft of the tenth rib. The posterior border lies beneath the cephalic border of the eleventh rib. The whole spleen (unless enlarged) lies dorsal to a plane passed through the midaxillary lines and is lateral to a line from the left sternoclavicular joint to the tip of the left eleventh rib. In deep inspiration the spleen is greatly depressed and if enlarged may be felt beneath the ribs.
20 gm. On the other hand, spleens weighing 3000 to 4000 gm. are sometimes foimd. These are usually, however, associated with an acute infectious disease, such as malaria or typhoid fever, or a progressive metamorphosis, such as leukemia.
Congenital absence of the spleen is one of the rarest anomaUes. The presence of more than one spleen is the commonest anomaly of the spleen. Adami has found accessory spleens to occur in 11 per cent, of all autopsies. They are round or oblong and vary in size from a pea, or smaller, to a walnut. There are most often one or two but there may be twenty or more. They are found near the hilus on the dorsal side of the gastroUenal ligament, less often, in the great omentum, in the mesentery, on the wall of the intestine, or in the tail of the pancreas.
In certain cases the left lobe of the liver is very long and prolonged far to the left and separates the spleen from the diaphragm. This is the rule in the foetus and is often found in the infant but is exceptional in the adult.
Exceptionally the spleen may be placed far caudal to the normal situation extending into the iliac region and even into the pelvis. This is due in part to congenital laxness of the supports, also to increase in weight. The spleen has been found in almost every part of the abdominal cavity and in transposition of the viscera it is upon the right side.
One or more notches on the anterior border are present according to Parsons in 93 per cent, of the oases, two or more in 66 per cent., but five, six, or seven much more rarely. On the posterior border notches are found in 32 per cent, of the cases, and on the inferior border in 8 per cent. In 20 per cent, of the cases a marked fissure, occasionally more than one, is found on the diaphragmatic surface. Most frequently it begins at one of the notches in the posterior border and passes for a distance across the surface, rarely reaching the anterior border. Occasionally such a fissure starts from the anterior border and rarely there is such a fissure connecting with neither border.
splenic nodules
Structure. — The peritoneal covering of tlie spleen, tunica serosa, is intimately bound to the underlying, whitish, highly elastic fibrous capsule, the tunica albuginea (fig. 1067). This is composed mainly of white fibrous connective tissue but contains numerous fine elastic fibers, and a few smooth muscle fibres. It is much thicker than the serous covering and completely invests the spleen. From its dee]) s\irt':ice the tunica albuginea gives off into the interior numerous trabecule, trabeculae lienis, which join with one another and form a framework in which course the blood-vessels, more especially the veins. It is through the contraction of the smooth muscle fibres in the tunica albuginea and trabeculae, that the regular periodic contraction and expansion of the spleen is produced.
In the meshes of the trabecular network, lymphoid tissue which forms the proper splenic tissue, the pulpa lienis, is located. This is soft, friable, and dark brownish or bluish-red in colour. In this, in a fresh spleen, are seen small round whitish or greyish masses from .25 to 1.5 mm. in diameter, the Malpighian corpuscles [noduli lymphatici lienales; Malpighii].
line masses of spleen-pulp about 1 mm. in diameter, known as splenic lobules. Each lobule is bounded by three main trabeculae, from each of which secondary trabeculoB pass into the substance of the lobule incompletely subdividing it into compartments, filled with splenic pulp, arranged in the form of anastomosing columns or cords and designated as pulp-cords. The branches of the splenic artery, after coursing for a short distance in the main trabeculae, leave these, and, after further division, become surrounded with a layer of adenoid tissue, which layer presents here and there irregular thickenings forming the Malpighian corpuscles. An arterial branch, surrounded with adenoid tissue, enters the apex of a splenic lobule, constituting its intralobular vessel, which, soon after entering the lobule, loses its adenoid sheath and then sends a branch to each of the above-mentioned compartments. These branches do not anastomose. They give off terminal branches which course in the pulp-cords, form dilations, ampuUse, and terminate directly or indirectly in the large venous spaces found between the pulpcords. From the latter the blood passes, by means of small intralobular veins, to interlobular veins situated in the trabeculae bounding the lobules. Some of the ampullae are connected with one another by capillary branches.
Blood-supply. — The spleen receives its blood from the splenic artery, which is very large in proportion to the size of the organ it supplies. It divides in the phrenicolienal ligament into from three to six or eight branches, rami lienales (fig. 1062), which enter the spleen at the hilus. After entering the spleen the arteries divide and subdivide and run to their termination in the ampullae without anastomosing. They form what are known as terminal arteries. The main splenic artery is very tortuous. The vein, vena lienalis, leaves the spleen usually by the same number of branches as the entering artery. These imite in the phrenicohenal ligament to form a large trunk which is straighter than the splenic artery and hes caudal to it.
The lymphatics. — A superficial and a deep set of lymphatics have been described in the spleen. The former is said to form a plexus beneath the peritoneum and the latter to be derived from the fine perivascular spaces in the adenoid tissue around the vessels. From these several trunks arise and joining at the hilus pass between the layers of the phrenicolienal hgament to empty into the lymph-glands dorsal to and around the cephalic border of the tail of the pancreas. The presence of both superficial and deep sets of lymphatics in the human spleen has been denied by some investigators. According to Mall, there is no deep set.
The nerves. — The nerves are derived from the right vagus and from the coeliac plexus. They enter the spleen at the hilus, accompanying the branches of the lienal artery. They are composed mostly of non-medullated fibres which form a rich plexus around the arteries supplying the muscular fibres in the media while a second group has been traced to the muscular fibres of the trabecule.
Development of the spleen. — The first anlage of the spleen is seen in the fifth week of foetal life as a swelling on the dorsal (left) surface of the mesogastrium. This is due to an increase in the mesenchymal cells as well as to a thickening of the coelomic epithelium. This latter becomes stratified, and indistinctly differentiated from the underlying embryonic connective tissue through the transformation of the deepest of the epithelial cells into mesenchymal cells. As development proceeds the thickened mass becomes entirely isolated and the ccelomic epithelium covers it as a single layer.
The arteries are seen first as a capillary network throughout the organ which considerably later become arranged as tufts of widened capillaries, the anlage, of the vascular structural unit. These spherical groups of arterial capillaries leading by wide openings into a wide meshed venous plexus are boimded by trabecule from the capsule. The number of structural units in the spleen seems to be fixed fairly early but the size and complexity changes greatly. The spherical mass with a single central artery changes to the adult condition where the central artery gives off side branches, each of which has a spherical mass of capillaries, and the pulp intervenes between the artery and the vein so that the capillary circulation of the early embryo becomes the cavernous circulation of the adult. The lienal lymphatic nodules of Malpighi and the splenic pulp appear only in the latter half of embryonic life.
The thyreoid gland [glandula thyreoiclea] is an extremely vascular, ductless gland, whose internal secretion, acting as a stimulus to the tissues, has a profound influence on the nutrition of the body and on the nervous system. It is a single organ composed of two lateral, frequently unsymmetrical, masses, joined together by a transverse median band. The median transverse band or isthmus [isthmus gl. thyreoidese] is thin and narrow, and often has a long slender process, ' the pyramidal lobe [lobus pyramidalis], extending from it cephalically. The lateral parts or lobes [lobi, dexter et sinister] form the principal mass of the gland.
The consistency of the thyreoid gland is uniformly soft and compressible. The colour is reddish, with a brownish or yellowish cast, but becoming more bluish or reddish with changes in its blood content.
The size is subject to considerable individual variation and is slightly greater in women than in men. The normal thyreoid gland measures from 4 to 6 cm. in width at its widest part. The lateral lobes measure from 5 to 8 cm. in length.
THE THYREOID GLAND
about 2 cm. in width, and from 1.5 to 2.5 cm. in thickness. The right is usually a little longer than the left. The isthmus averages from .6 to .8 cm. in thickness and from .5 to 1.5 cm. in height.
light as 20 grams, and others weigh as much as 60 grams.
When hyperemio or congested the size of the gland may be markedly augumented. This occurs normally in most women at puberty and dm-ing menstruation and pregnancy. In various abnormal conditions of the gland there is an increase in size, sometimes to a marked degree. These enlargements are ordinarily grouped under the term struma or goitre, and may be associated with either a hyper- or hyposecretion of the gland. Decrease in size is common in old age and may appear prematurely in certain diseases.
The shape of the gland as viewed from the ventral surface is that of a capital U with the concavity directed cephahcally (fig. 1068). The sides of the U are formed of the more or less elongated lobes connected slightly cephahc to their
thickened caudal ends by the thin transverse isthmus. In transverse sections through the isthmus the gland is also U-shaped with the concavity directed dorsally, the lobes being on each side and the isthmus ventral to the trachea (fig. 1068). The surface of the gland is somewhat unevenly roughened.
The isthmus glandulae thyreoidae usually becomes wider laterally where it is attached by its two extremities to the lateral lobes (figs. 1068, 1069). Its ventral surface which is flat or somewhat convex is covered superficially by the subcutaneous tela and skin and beneath these by the superficial and middle layers of the cervical fascia. Between the layers of cervical fascia and close to the median line is the sterno-hyoid muscle and more laterally and deeper the sterno-thyreoid muscle. The dorsal surface is concave and is in relation with the first two to four rings of the trachea and sometimes with the cricoid cartilage.
The size and form of the isthmus is subject to considerable variation. It may be very short. Rarely it is wanting entirely or connects with but one lateral lobe. Its superior border is, as a rule, concave and is connected in many cases with the pyramidal lobe. The caudal border, although usually on the third ring of the trachea and 2.5 to 3 cm. from the jugular notch of the sternum, may be especially developed so that it extends caudally beyond the lateral lobes and produces a process which is known as the medial lobe.
The pyramidal lobe is usually a narrow elongated flattened somewhat conical process of thyreoid tissue representing the persistent portion of the median embryonic thyreoid (fig. 1069). Its base is attached ordinarily to the left side of the
superior border of the isthmus and its apex which extends cephalically a variable distance, often to the superior border of the thyreoid cartilage, is attached by a fibrous cord, the thyreoid ligament.
these extremes. It is closely adherent to the subjacent structures, usually at one side of the median line, more often the left. The superficial relations of the pyramidal lobe are similar to those of the isthmus. Its deep surface is in relation also with the cricoid and thyreoid cartilages, the crico-thyreoid muscle and the hyo-thyreoid ligament.
The pyramidal lobe, though usually single, may be double or bifid at its caudal end, one process joining each lateral lobe. It may be attached in the angle between the isthmus and one of the lateral lobes, or to the lateral lobe itself. It may be cylindrical, band-hke, or swollen at its centre or cephaho end and is occasionally entirely separate from the rest of the th}Teoid or divided into separate detached parts, thus forming accessory th}Teoids. The apex in some cases extends to the middle of the thyreohyoid membrane or rarely to or beyond the hyoid bone or the process may be quite short. In the thyreoid ligament, attached to the apex, muscle fibres are sometimes found, aberrant parts of the infrahyoid muscles, the levator of the thyreoid gland.
The thyreoid lobes, right and left, are placed on each side of the trachea and larynx (figs. 1068, 1069, 1070). Each lobe is somewhat pyramidal in shape and presents for examination a base, an apex, a medial, a ventro-lateral, and a dorsal surface.
It is separated from the jugular notch of the sternum by a distance of 1.5 to 2 cm. but when the head is extended the distance is greatly increased. It is in relation with the inferior thyreoid artery and numerous veins, mostly tributaries of the inferior thyreoid vein.
The apex is pointed or rounded (figs. 1068, 1069). It is directed cephalodorsally and is situated at the dorsal border of the lateral lamina of the thyreoid cartilage at the level of its caudal, or rarely its middle, third. '
It is covered by the sterno-thyreoid muscle beneath which the superior thyreoid artery accompanied by the corresponding vein crosses the apex to reach the gland. It is also crossed in this situation by the external ramus of the superior laryngeal nerve as it passes to the cricothyreoid muscle.
The medial surface of the lateral lobe is concave and intimately bound to the trachea and cricoid cartilage (fig. 1070). Toward the apex it becomes more flattened where it comes into contact with the lateral lamina of the thyreoid cartilage.
At the border where this surface joins with the dorsal surface it is in relation with the oesophagus and pharynx, and in the angle between these structures and the trachea and larynx it is close to the recurrent laryngeal nerve.
The dorsal surface (fig. 1070) is broad and rounded caudally, but toward the apex is reduced to a mere border. It lies upon the fascial sheath containing the common carotid artery, the jugular vein, and vagus nerve, most intimately related to the common carotid artery which usually produces a groove in it.
The inferior thyreoid artery sends large branches over this surface. The inferior thyreoid veins also have large branches here. Imbedded in the connective tissue in relation with this surface the parathyreoid bodies are found, and in some cases the recurrent nerves are placed so far laterally that they also touch this siu-face. In many cases the sympathetic trunk and the middle cervical ganglia of the sympathetic with the cardiac branches are closely related to the dorsal surface of the gland.
More superficial on its lateral aspect is the sterno-cleido-mastoid muscle. The above muscles are enclosed by the superficial and middle sheets of the cervical fascia. In the subcutaneous tela the platysma muscle spreads over the gland. This surface of the gland is covered by a plexus of veins and by branches of the superior thyreoid artery.
Accessory thyreoid glands are small masses of glandular tissue one or more of which may be found situated in the median line or at one side of it anywhere between the isthmus and the root of the tongue. They vary considerably in size and represent parts of the pyramidal lobe or isthmus which have become completely separated from the rest of the gland. In structure they are composed of the same tissue as the rest of the gland.
Fixation. — In addition to the connective tissue which binds the thyreoid gland to the trachea, it is attached by the connection of its capsule with the cervical fascia and by the fibrous prolongations from the capsule.
These prolongations are found medially attaching the isthmus and adjoining portions of the lateral lobes to the ventral surface of the cricoid cartilage, the caudal border of the thyreoid cartilage, and the sheath of the crico-thyreoid muscles, and laterally attaching the lateral lobes to the trachea and lateral surface of the cricoid cartilage. In addition to these the connection of the vessels and nerves to the gland helps to fix it in position.
capsule, may be divided into two layers, superficial and deep.
The superficial layer intimately connected with and derived from the fascia colli as pointed out above has an important fimotion in supporting and fixing the gland. This layer is in some cases thin and transparent; in other cases it is very tough and thick. It is connected by loose areolar tissue with the thin deep layer of the capsule. Between these two layers the larger vessels run for a space before entering the gland and the veins, particularly, form here considerable plexuses.
From the deeper layer of the capsule numerous trabeculse and septa carrying blood-vessels, lymphatics, and nerves pass into the gland and imperfectly separate its parenchyma into irregular masses of variable size, the lobules [lobuli]. Each lobule is composed of a number of closed, non-communicating, irregular, spherical, ovoid, or sometimes branched alveoli, acini or vesicles, varying in size from .045 to .22 mm. in diameter and separated and bound together by a vascular connective tissue continuous with that surrounding the lobules and with that of the cap-
FiQ. 1071. — Arteries of the Thyreoid Gland, Anterior View. 1. Lateral lobe; 1' pyramidal lobe; 2, trachea; 3, thjrreoid cartilage; 4, crico-thyreoid membrane; 5, hyo-thyreoid membrane; 6, 7, 8, 9, inferior thyreoid artery and branches; 10, 11, 12, 13, 14, 15, superior; thyreoid artery and branches; 16, thyreoidea ima. (Testut and Jacob.)
the secretion of the epithelial cells.
The vesicles are lined with a single layer of epithelial cells of a fairly uniform cuboidal or columnar shape, becoming flattened in distended vesicles and ia old age. The cells are not supported by a basement membrane but are in close relation with connective tissue and capillary blood-vessels. An extremely rich lymphatic network surrounds the vesicles and the lymph-vessels come into intimate relation with the cells. Through these vessels the secretion is conveyed from the gland to the general circulation.
The superior thyreoid arteries divide into two, three, or more main branches which reach the gland near the apex of the lateral lobes and supply mainly the ventral and medial surfaces of the cephahc portion of the lobes (fig. 1071). There is usually also a dorsal branch, which anastomoses with a branch from the inferior thyreoid. One of the ventral branches frequently connects along the cephalic border of the isthmus with its fellow of the opposite side. The inferior thyreoid arteries break up into two or three main branches, occasionally into many fine twigs, which reach the dorsal surface of the lateral lobes near the eaudolateral borders and supply
mainly the dorsal and lateral surfaces of the caudal part of the gland (fig. 1071). There is usually a well-marked branch which passes cephalioally to anastomose with a good-sized branch from the superior thyreoid. Small branches are distributed to the ventral surface of the caudal portion of the lobes and isthmus. The small fifth artery, the thyreoid ima artery, occasionally present, ascends on the ventral surface of the trachea and reaches the gland at the caudal border of the isthmus or of either lobe. It anastomoses with the other arteries which may be correspondingly reduced in size. The above-mentioned arteries branch freely and are distributed over the surface of the gland between the two layers of the capsule where they anastomose extensively with one another and with the arteries of the opposite side. From the surface plexus branches pass with the septa and trabeculse through the gland to break up into the capillary plexuses around the vesicles.
The relation of the inferior thyreoid artery to the recurrent nerve is important from a surgical point of view but unfortunately is not constant. In some cases the nerve is ventral to the artery, more often on the right, in other cases it is dorsal and often the nerve passes between the branches of the artery. Their relation is most intimate close to the trachea Fig. 1073.
Fig. 1072. — Vessels of the Thyreoid Gland, Anterior View. 1, 2, 3, Lateral lobes and isthmus; 4, pyramidal lobe; 5, hyoid bone; 6, thyreoid cartilage; 7, trachea; 8, common carotid;. 9, internal jugular; 10, thyreo-linguo-facial vein; 11, superior thyreoid artery; 12, inferior laryngeal vessels; 13, middle thyreoid vein; 14, subclavian artery; 15, inferior thyreoid artery; 16^ inferior lateral thyreoid veins; 17, inferior medial thyreoid veins; 18, left innominate vein; Ift aortic arch; 20, vagus nerve. (Testut.)
The veins (fig. 1072) issue from the substance of the gland along the septa which penetrate from its capsule. Between the two layers of the capsule they form a rich plexus of large vessels from which three large branches issue on each side.
The superior thyreoid veins leave the capsule of the ventral surfaces of the lateral lobes near their apices and pass cephalo-laterally to empty into the internal jugular veins, sometimes with the facial veins. The middle thyreoid veins are sometimes absent, when present they^are often very small and pass from the lateral border of the lateral lobes laterally to empty in to' the internal jugular vein. The inferior thyreoid veins arise from the caudal and lateral part of the dorsal surfaces of the lateral lobes and pass caudolaterally to open into the innominate veins. Ventral to tlie trachea, caudal to the isthmus, the two inferior thyreoid veins are connected by numerous cross anastomoses and occasionally they open by a single trunk which joins the left innominate vein. A thyreoidea ima vein is sometimes present.
The lymphatics of the thjTeoid gland begin as abundant plexuses arovmd the vesicles of the gland lobules. These connect with the interlobular branches which empty into radicles accompanying the blood-vessels through the septa to the surface of the gland where they join a considerable plexus placed between the two layers of the capsule. From the cephalic portion of the isthmus and lobes efferent vessels extend cephalo-medially to one or two small
pre-laryngeal glands and cephalo-laterally along with the superior thyreoid artery to the deep cervical glands. From the caudal part of the lateral lobes and isthmus efferent vessels pass caudally to some small pre-tracheal glands and caudolaterally to the deep cervical glands.
from the middle and inferior cervical ganglia and accompany the arteries to the gland.
Development. — The thyreoid gland is first seen in very young embryos as a prominence on the ventral wall of the pharynx. This becomes a stalked vesicle and divides into lateral lobes. The stalk elongates forming the thyreoglossal duct of His. Later the lumen is obliterated and the duct is then represented by an epithehal cord which soon loses its connection with the pharynx. It opens at first cephalic to the regular second branchial arch on the summit of the tuberculum impar but later shifts to its caudal boundary (Grosser). It is represented in the adult only by a short blind pouch, the foramen csecum but very rarely a considerable duct may be present. The bilobed mass appears to shift caudally, increasing m size and spreading laterally and dorsally. The median cord of cells formed from the stalk becomes the isthmus and the p3rramidal lobe, when this is present, the lateral portions form the lateral lobes. The gland is now composed of irregular, in general transversely disposed cords of cells. More rapid growth later occurs in the centres of the lateral lobes and the cell cords become closely packed with,Jittle connective tissue between. Lumina appear in different places in the cell cords and the cell cords are broken up into groups of cells; in these the lumina continue to appear even up into early childhood. On each side, diverticula from the more caudal pharyngeal pouches, the ultimobranchial bodies, come into contact with the dorsal and lateral parts of the anlage of the thyreoid gland and become partly enclosed in the neighbourhood of the transversely running cell cords. This core of cells becomes either a compact body or an irregular group of cells and is probably not transformed into thyreoid tissue.
essential to life.
The usual number is four, two on each side, in relation with the lateral lobes of the thyreoid gland (fig. 1073) . In colour they are yellowish with more or less of a reddish or brownish tint but lighter than the thyreoid gland. Their consistency varies somewhat but usually it is softer than that of the thyreoid gland. The shape of the majority of the glands is a flattened ovoid, sometimes tapering at one or both ends, rarely a flattened circular disc. At some place on the surface there is usually a depressed hilum where the artery enters and the vein leaves. The average size of the glands is 6 to 7 mm. in length; 3 to 4 mm. in width and 1 to 2 mm. in thickness. Occasionally they may be found 15 mm. in length. They
THE THYMUS 1319
weigh from .01 to .1 gm. with an average of .035 gm. From their situation they have been divided into a superior, or internal, derived from the fourth branchial pouch, and an inferior, or external, derived from the third branchial pouch.
The superior parathyreoid glands (fig. 1073) are found, as a rule, on the dorsal surfaces of the lateral lobes of the thyreoid gland at about the junction of the cephalic and middle thirds Occasionally they may be situated in the areolar tissue at the level of the apex of the thyreoid gland or cephalic to it. They may be ventral to the prevertebral layer of the cervical fascia, on the dorsal wall of the oesophagus or pharynx and close to the dorsomedial margin of the thyreoid gland. They may also be placed at the level of the caudal border of the cricoid cartilagel rarely as high as the inferior cornu of the thyreoid cartilage or as low as the sixth trachea, ring. Sometimes they are imbedded completely in the thyreoid gland. As a rule, they are tightly attached to the capsule of the thyreoid gland or situated between its layers.
The inferior parathyreoid glands (fig. 1073) are less constant in their situation than the superior. They usually are found in relation with the dorsal surface of the lateral lobes of the thyreoid glands, not far from their bases. They may be quite outside the region of the thyreoid gland along the carotid arteries or tlie sides of the trachea, or they may be placed more cephalically than usual or extend caudal to the gland as far as the tenth tracheal ring, even into the thorax. They are imbedded, when caudally placed, in fatty areolar tissue in relation with the apex of the thymus gland and the inferior thyreoid veins or applied against the oesophagus.
The parathyreoids are intimately related to branches of the inferior thyreoid artery, a separate branch of which supplies each of them. When there is a large branch of the inferior thyreoid artery anastomosing with the superior they are more or less in line with this.
Each parathyreoid gland is surrounded by a fibrous capsule from which extremely vascular septa and trabecula; penetrate into the gland separating and binding together the masses of polyhedral cells which are arranged in solid groups or intercommunicating cords of varying sizes and shapes.
The cell cords, as a rule, are not arranged like the thyreoid vesicles. At times the secretion may accumulate and produce a vesicular appearance and the secretion then closely resembles colloid. Two kinds of cells, oxyphile and principal cells, have been described; but the intermediate forms suggest that these are the same sort of cells in different stages of functional activity. The blood-vessels are distributed m the connective tissue of the trabeculae and thus their sinusoids are brought into close connection with the cells of the gland. The nerves are also distributed along the septa. In the highly vascular connective tissue ^between the cell cords fat cells are found separate or in groups.
The number of parathyreoid glands found by different investigators varies. The average number in a series of cases is less than four. Whether this is due to a real absence of the glands or to failure to find them due to their aberrant location, their inclusion in the thyreoid gland, or the fusion of two glands, is not clear. In some cases it is the superior glands, in other cases the inferior glands, which appear to be missing. On the other hand various competent observers have reported finding more than four parathyreoid glands. Five or six are occasionally found; as many as eight have been recorded in one instance. In these cases the number on a side may not be symmetrical. The increased number may be due to the separation of buds in the course of development. The parathyreoid glands are liable to be associated with accessory thymus masses, with small lymphatic glands, and with fat lobules; and as they may somewhat resemble each of these, they may be mistaken unless a microscopic examination is made.
Blood-supply. — Each parath3Teoid gland is supplied by a single separate artery derived, as a rule, from one of the glandular, muscular, or oesophageal branches of the inferior thyreoid artery or from the anastomosing branch between the superior and inferior thyreoid arteries. When the glands are in aberrant positions their arteries may be derived from the nearest source. The arteries are distributed along the trabeculae and septa. The veins returnmg the blood either follow the arteries or they pass to the surface of the gland where they break up into a plexus of thin-walled vessels. Upon leaving the gland the veins empty into some one of the branches of the thyreoid veins.
Development. — The parathyreoids (epithelial bodies) begin as proliferations of the epithelium on the oral and lateral walls of the dorsal diverticulum of the third and fourth pharyngeal pouches. The cells show early a histological differentiation with vacuolated and reticulated plasma. The common pharyngo-branchial ducts diminish in size and become constricted off and separated from the pharynx. The parathyreoid glands later become independent and separated from the thymus anlages. The epithelial cells grow out in the form of cords separated by connective tissue and in intimate relation to the blood-vessels. Different kinds of cells are not distinguishable until postfcetal life when evidence of secretion begins.
THYMUS
The thymus is a transitory organ of epithelial origin, but in structure resembling the lymphoid tissue. Its function is not clearly understood but it seems to be intimately associated with the growth and nutrition of the individual, and it is classed with the ductless glands of internal secretion.
It is situated in the ventro-cephalic part of the thorax and extends into the caudal part of the neck (fig. 1074). It lies between the two pleural sacs ventral to the heart and great vessels, dorsal to the sternum and the sterno-thyreoid and sterno-cleido-mastoid muscles.
Although arising from the branchial clefts one on each side of the neck, the two portions become so closely associated that they are usually spoken of as one. Each of these parts is ordinarily regarded as a lobe of the thymus [lobus, dexter et sinister].
In colour the thymus is pinkish or reddish grey in the foetus and newborn, becoming greyish white in the adult or yellowish as it undergoes involution. It is composed of soft, yielding tissue more friable than the thyreoid or spleen.
In size the thymus varies greatly. Under normal conditions it appears to attain its maximum size at about the age of puberty, and to continue large as long as the body continues to grow and then to undergo a gradual involution.
Xiphoid process
It is, however, very sensitive to any nutritive changes of the individual and becomes very small, even in the infant, under the influence of wasting diseases. It not infrequently exists in the adult only as a vestige but in some cases it may remain large until middle age or later. At birth it is usually from 50 to 60 mm. long cephalo-caudally and about half as broad.
The weight varies with the size. It is given by Hammar as over 13 gm. at birth, increasing to double this between the sixth and the tenth years and gaining its maximum of between 37 and 38 gm. between the eleventh and fifteenth years. From this time the weight decreases until between the ages of fifty-six and sixty-five it weighs between 25 and 26 gm. and at seventyfive years may be as light as 6 gm. The involution of the gland is not accompanied by a corresponding reduction in size and weight as the thymic tissue is gradually invaded by fatty tissue which maintains to some extent the form of the organ.
widest and largest part of the organ and has no distinct separation from the extremities. The inferior extremity is also broad and is known as the base. It rests on the pericardium, ordinarily extending as far caudal at birth as the atrioventricular furrow but rarely it may extend as far as the diaphragm. The superior extremity is much elongated and extends into the neck. It is represented by two horns nearly always unequal in size the left being usually the larger. It extends nearly to the thyreoid gland, in some cases reaching it.
The cervical portion presents for examination an anterior surface and a posterior surface. The anterior surface is convex and is in relation with the sterno-thyreoid and sterno-cleidomastoid muscle. The posterior surface is concave and rests medially upon the anterior surface of the trachea, laterally upon the common carotid artery and sometimes on the left side upon the oesophagus.
The thoracic portion of the thymus is much more important representing four-fifths of the organ (fig. 1075). It presents for examination an anterior, a posterior, and two lateral surfaces. The anterior surface is dorsal to the sternum from which it is separated cephalically by the origin of the sterno-thyreoid muscle. To a less extent it is in relation with the sterno-clavicular articulation and comes into contact laterally with three or four of the cephalic sterno-costal articulations and lateral to this with the internal mammary artery. The posterior surface is largely concave and is in relation caudally with the pericardium which separates it from the
right atrium and ventricular portion of the aorta and pulmonary artery. The middle part is in relation with the aorta and to the right of this with the superior vena cava. The cephaUc part is in relation with the branches of the aorta and superior vena cava. The lateral surfaces are somewhat flattened and are separated from the lungs by the mediastinal pleura. The phrenic nerve on the right side runs in the pleura near the dorsal border of this surface, on the left it is, as a rule, not in direct contact with the thymus.
Structure. — The two lateral lobes of which the thymus is composed are rarely of the same size; the right is usually the more strongly developed. They are joined at an oblique plane so that the ventral surface of the right is narrow and its dorsal surface broader and the reverse condition is found in the left lobe. The two lobes are separated from one another by connective tissue. Rarely the two are joined by a medial portion, isthmus, near the middle or toward the caudal end (fig. 1076).
Each lobe of the thymus is completely surrounded by a thin dehcate connective-tissue capsule from which numerous septa extend through the gland accompanied by the blood-vessels and nerves. The capsule is composed mainly of white fibrous connective tissue with some elastic fibres. It rarely contains much fat in the newborn but the amount of fat increases as development and involution proceed. Fibrous prolongations from the capsule may extend from the apices of the lobes to be attached to the cervical fascia in the region of the lateral lobes of the thyreoid gland, acting as suspensory ligaments for the gland.
The lobes of thymus are divided into numerous small lobules [lobuli thymi] 4 to 11 mm. in diameter. These are of roundish or polyhedral shape with bases toward the surface where they show as polygonal areas. The lobules are separated and also bound together by the loose fibrous tissue septa which extend from the capsule.
Each of the primary lobules of the thymus is divided into a number of secondary lobules or follicles 1 to 2 mm. in diameter. These lymphoid-like masses of tissue are composed of a reticulum containing in its meshes lymphocytes or thymus corpuscles. The tissue is denser near the surface, forming a cortex and passes gradually into a tissue with looser meshed reticulum near the centre, medulla. In the medulla there are nests of concentrically arranged degenerated epitheKal cells enclosing a central mass of granular cells containing colloid. These
t,The arteries of the thymus are somewhat varied in their origin, usually derived from the internal mammary and inferior thyreoid of each side; branches are sometimes received from the innominate, subclavian, and superior thyreoid arteries. They reach the gland in various places and spreading out in the capsule pass with the trabeculae through the gland to form a plexus around each small lobule. From this capillaries pass through the cortex to the medulla. The veins issue from the thj'mus in various places and are seen as numerous branches on its surface. The efferent vessels drain into various veins, mostly into the left innominate vein, also smaller branches into the internal mammary and inferior thyreoid veins.
The lymphatics arise around the small lobules and pass through the interlobular septa to the sm-face from which they are drained into small lymph nodes near the cephalic extremity, into glands ventrally between the thymus and the sternum, and into other glands dorsally between the thymus and the pericardium.
The nerves of the thymus are very minute. They are derived from the cervical sympathetic and from the vagus and reach the thymus for the most part along with the bloodvessels which they accompany through the septa.
Arch of aorta
Development. — The thymus arises from the endodermal portion of the third pharyngeal pouch on each side, as a thickening due to an increase in the epitheUal cells, followed by the production of a diverticulum. At about the sixth week the connections of the pouches with the branchial clefts are cut off but a strand of tissue may persist to represent the stalk. These thick-walled cylinders become sohd cords, elongate so as to extend caudally into the thorax, and enlarge by a series of secondary buddings. The glands of the two sides come into contact and become intimately associated. The cephahc portion, as a rule, later atrophies and disappears. Occasionally a small part of it remains near the thyreoid cut off from the rest of the gland as an accessory thymus. From the fourth pharyngeal pouch rarely a thymus bud may be developed which produces in the adult also an accessory thymus. The epithelial character of the cells remains plainly evident for a time, then the characteristic differentiation into lymphoid structure, cortex and medulla appears. The reticulum and concentric corpuscles are undoubtedly of epithelial origin; but the thymus lymphocytes are considered by Hammar and others as leucocytes which have migrated to the thymus, while they are regarded by
THE CHROMAFFIN SYSTEM
It has recently been shown that in connection with the ganglia of the sympathetic nervous system, special cells, other than the nerve cells, are found. These differ from the nerve cells in that when subjected to the action of chromic acid salts there can be demonstrated in their protoplasm small granules which take on a darker stain. These cells are therefore known as chromaffin cells. They, with the cells of the sympathetic system, are derived from the ectoderm. They appear first as indifferent cells, the sympatho-chromaffin cells. Some of these later develop into sympathetic ganglion cells, others into chromaffin cells. Some of these latter cells remain, isolated or in groups, permanently associated with the sympathetic ganglia, the paraganglia; others become separated and form the medullary portion of the suprarenal glands, the aortic paraganglia, and the glomus caroticum.
The suprarenal glands [glandulae suprarenales] or adrenal glands are small irregularly shaped glandular bodies composed of two quite different organs. In the lower vertebrates these two parts are entirely separated from one another
but in man and the mammals they have become joined together one within the other. The external cortical portion, of unknown function, is developed from the mesoderm. The internal medullary portion is derived from the sympatho-
Basis gl. suprarenalis
chromaffin tissues and thus from the ectoderm in common with the sympathetic nervous system. This part of the suprarenal glands is known to produce an internal secretion which reaches the general circulation through the veins and
the muscle and other tissues innervated by the sympathetic system.
Situation. — The glands are deeply placed in the epigastric region (fig. 1080) lying in the dorsal and cephalic part of the abdominal cavity, one on either side of the vertebral column in variable relation with the upper extremity of the kidney of the corresponding side.
Rarely they retain the fcetal relation, capping the superior extremity of the kidney and extending a little upon both medial and lateral borders. More frequently (especially on the left) they are placed more upon the medial borders of the kidneys, extending (on the left) as far caudal as the hilus, sometimes coming in contact with the renal vessels. Aii intermediate position is often found, especially on the right. In the high positions the suprarenals may be on a level with the tenth intercostal space or eleventh rib. In the low positions they may extend as far caudally as the first lumbar vertebra. The left is usually, but not always, a little higher than the right, corresponding to the position of the kidneys.
Fixation. — The suprarenals, enclosed in the renal adipose capsules, are attached to the renal fascia by connective-tissue strands and are loosely bound by connective tissue to the kidneys. The attachment to the kidneys is, however, so loose that the suprarenals are not dislocated when the kidneys are displaced. In addition to the attachments common to them and to the kidneys, they are joined by connective-tissue bands to the diaphragm, vena cava, and liver on the right side and to the diaphragm, aorta, pancreas and spleen on the left. They have also additional means of fixation through the arteries, veins, and nerve fibres which enter and leave them, and through the parietal peritoneum which in places covers their ventral surfaces.
Size and weight. — The size of the suprarenals is subject to considerable variation within physiological limits, in some cases being relatively twice as large as in others. The two glands are rarely of the same size, the right being more often the smaller.
Proportionately they are much larger in the foetus and embryo than in the adult, but they do not decrease in size in old age. They appear to be slightly lighter in women than in men. The average weight in the adult is from 4 to 54 grams. As a rule, they measure about 30 mm. in height; 7 or 8 mm. in thickness; and have a breadth at the base of about 45 mm. They augment in volume during digestion and also increase in size during the acute infectious diseases and in intoxications such as uremia.
Colour and consistency. — The suprarenal glands as seen from the surface have a yellowish or brownish-yellow colour. Upon section the colour of the surface layer appears a little darker while the central part of the gland appears greyish or, if it contains much blood, of a reddish colour. If some httle time has elapsed since death, the central part of the suprarenal may be almost black in colour.
readily detected in it.
Form. — The suprarenal glands are markedly flattened dorso-ventrally. Their surfaces are roughened by irregular tubercles and furrows. They vary considerably in shape (figs. 1077, 1078). The right gland is usually somewhat triangular in outline while the left is, as a rule, semilunar. Each gland has an anterior and a posterior surface, a base and an apex, a medial and a superior margin.
look ventro-laterally. It is marked by a distinct transverse, oblique, or nearly vertical fissure, the hilus suprarenalis. At this point a small artery enters and the principal suprarenal vein takes exit from the gland. These surfaces are in relation with different organs on the right and left sides.
The anterior surface of the right gland is in the greatest part of its extent in contact with the posterior surface of the hver, upon which it produces the suprarenal impression. The medial edge of -this surface is overlapped, cephalioally by the inferior vena cava and caudally by the duodenum. The gland is situated between the two layers of the coronary hgament, in most cases, in direct contact with the liver to which it is bound by loose connective tissue; but, at times, the peritoneum which covers the ventral surface of the kidney extends for a greater or less distance between the suprarenal and the liver.
The anterior surface of the left gland, in some cases, may be in contact in its cephalic part with the left lobe of the liver and also, at times, with the spleen. The middle and major part lies against the fundus and cardiac end of the stomach, while caudally the suprarenal is often
tissue, but from which it is separated by an extension of the renal adipose capsule.
The base [basis gl. suprarenalis] is a narrow elongated surface distinctly hollowed out, which lies in contact with the superior extremity of the kidney or its medial margin, cephalic to the hilus.
extends more or less vertically to meet the superior border.
On the right it hes dorsal to the inferior vena cava cephalically and to the duodenum caudally and is close to, if not in contact with, the sympathetic cceliac ganglion. On the left the medial border lies dorsal to the stomach and caudally may be crossed by the pancreas and splenic vessels. It is in close proximity to the aorta and the coeliac sympathetic ganghon.
On the right it is irregular, straight or convex, and extends, dorsal to the liver, obliquely cephalo-medially to meet the medial border in a more or less acute point, apex suprarenalis, which is directed cephaUcally and somewhat medially. On the left the superior border is irregularly convex in shape and nearly horizontal in direction. It passes gradually over into the medial border without the intervention of any distinct apex. It is dorsal to the stomach and in some cases comes into contact with the spleen.
Accessory suprarenal glands [gl. suprarenales accessoriEe] are often foimd in the connective tissue in the neighbourhood of the principal organs. They are also sometimes found in the kidney near the internal spermatic veins and in the region of the sexual glands. The structures recorded as accessory suprarenal glands may be complete suprarenal glands composed of the cortex and medulla or they may be composed of the cortex only. Masses of chromaffin tissue representing the medulla are sometimes spoken of as accessory suprarenals but these more properly belong with the chromaffin system.
has also been noted.
Structure. — The suprarenal glands are surrounded by a thin and tough fibrous capsule composed mainly of white fibrous connective tissue. From the capsule numerous trabeculse are given off which pervade the gland and form septa between the groups and rows of cells. Within the capsule the suprarenal is composed of an external firmer yellowish layer, the cortex [substantia corticalis], and an internal softer whitish layer, the medulla [substantia meduUaris] (fig. 1079).
On section the cortex is seen to form by far the greater part of the gland and it is marked radially from the centre toward the surface by darker and lighter streaks. In its deepest part it is brownish yellow or red and is usually slightly torn where it joins the medulla. As frequently found at autopsy the cortex is separated from the medulla by a sUt filled with a soft dark brown or blackish mass caused by the breaking down of the deeper layer of the cortex. The medulla is a greyish, spongy, vascular mass which often because of its blood content appears of a reddish or reddish-brown colour.
The cortical portion of the gland is subdivided into a superficial, glomerular portion, zona glomerulosa; an intermediate, fascicular portion, zona fasciculata; and an internal reticular portion, zona reticulata, according to the peculiar grouping of the gland cells in these respective areas.
In the glomerular zone the cells are of irregular columnar shape, and grouped in coiled columns. In the fascicular zone the cells, which are of polyhedral shape, are arranged in more or less regular parallel columns, while in the reticular zone the cells form trabecute or groups. The reticular connective-tissue framework, continuous with the capsule, surrounds the cell masses and cell columns of the several zones. The cells of the medulla show an affinity for chromic acid — chromaffin cells — and are grouped in irregular masses separated by septa of the reticulum and venous spaces. The arteries form a close-meshed plexus in the capsule from which branches run more or less parallel toward the medulla forming a network around the cell columns of the glomerular and fascicular zones. This opens into a venous plexus of wide calibre in the reticular zone, which is connected with the vessels of the medulla. Small medullary arteries pass through the cortex without branching to end in a venous plexus in the medulla. The abundant wide-meshed venous sinuses in the medulla (sinusoids) join to form small central veins which converge towai'd the centre of the medulla to form the large central vein.
From the inferior phrenic artery, the superior suprarenal artery arises and passes toward the superior border of the gland. From the aorta the middle suprarenal artery takes origin between the coehac and superior mesenteric arteries and passes toward the medial border of the suprarenal. It is a branch of this artery which is usually found at the hilus along with the central vein. From the renal artery the inferior suprarenal artery arises and reaches the suprarenal near its base. These three arteries anastomose with one another and form a plexus in the capsule of the suprarenal from which the arteries for the interior of the gland are derived.
The large central vein from the medulla passes through the cortex to emerge at the hilus as the suprarenal vein, vena suprarenalis. The right vein opens usually into the inferior vena cava, where there is a valve, the left into the left renal vein. There may also be small branches connecting with the phrenic or the right renal vein.
The lymphatics of the suprarenals are very numerous and are represented by a superficial plexus in the capsule and a deep plexus in the medulla. These are connected by numerous anastomoses. They pass medially and converge into a number of trunks on each side which empty into lymph-glands situated along the aorta near the origin of the renal arteries. On the left side there is also the communication through the diaphragm with a posterior mediastinal gland.
The nerves are derived chiefly from the coeliac and renal plexuses but include filaments from the splanchnics, and according to some authors from the phrenic and vagus nerves also. These numerous fine twigs connect with the gland in many different places and form a rich plexus. Branches are distributed to the capsule, to the cortical substance, and to the medullary substance. Groups of sympathetic ganglion cells are found in the medullary part of the gland.
THE CAROTID BODY 1327
the mesothelium on both sides of the root of the mesentery into the mesoderm ventral to the aorta. A little later these become definite organs completely separated from the coelomic epithelium and are soon vasoularised, but the central vein does not become visible until considerably later. The suprarenal glands after their separation from the peritoneum form a ridge on either side of the posterior wall of the ca4om medial to the mesonephros. Some little time after the origin of the cortical portion of the gland has undergone cellular differentiation and has become surrounded by a delicate capsule, the medullary portion is formed by the migration of masses of sympatho-chromaffin cells from the medial side toward the centre of the organ so that they surround the central vein as the anlage of the medullary nucleus. They penetrate the cortical portion of the gland as development proceeds and become completely surroimded by it. These migrating masses are entirely or for the most part of chromaffin formative cells derived from the ectoderm. They are clearly differentiated from the cortical cells by their small size and darker colour, in stained sections. Migration of these cell masses into the gland seems to be continued even after birth. The differentiation of the cortex into three layers occurs late in development. The suprarenal glands are relatively large in foetal life; and their relation to the kidneys is secondarily acquired.
THE GLOMUS CAROTICUM
The carotid bodies [glomera carotica] are small ovoid or spherical bodies found at or near the point where the common carotid arteries divide into the internal and external carotids (fig. 1081). They are usually on the dorsal and medial side of the angle of bifurcation of the arteries. There is ordinarily one body on
Fig. 1081. — The Glomus Caroticum (Carotid Body). (From Testut, after Princeteau.) 1, Carotid body; 2, 3, 4, common, external and internal carotids; 5, int. jugular; 7, inf. cervical .sympathetic ganglion; 8, vagus.
each side, 5 or 6 mm. in length and 2 or 3 mm. in thickness. It is reddish-yellow in colour and is attached to the carotid by fibrous tissue and by the vessels and nerves which enter it. A small special fibrous band may sometimes be recognised binding it to the common, external or internal carotid artery.
The carotid body or gland is composed of two essential parts: (1) round, oval, or polyhedral epithelial cells which contain chromaffin granules, and are bound together by a mass of fibrous connective tissue; and (2) a rich plexus of capillaries and sinusoids forming a mesh. Large lymph-vessels surround the outside of the gland. The carotid gland has a very abundant nerve supply, mostly from the sympathetic system, and ganglion cells are foimd in it. It may receive twigs from the superior laryngeal, hypoglossal, or glossopharyngeal nerves, as recorded by some observers.
The size of the carotid body varies considerably. At times the carotid bodies are absent; in other cases they are so small that they can be detected only in microscopic sections; occasionally they are 8 mm. in length by 4 or 5 mm. in thickness. Rarely the carotid bodies may be broken up into two or more smaller masses boimd together by connective tissue. The carotid body may be larger in old individuals due to an increase in the connective tissue or vascular elements with a corresponding decrease in the epithehal cells. The origin is probably from sympathochromaffin cells but some investigators believe that they are derived from the endothehum of the blood-vessels and others that they arise from the endoderm of a branchial pouch.
THE AORTIC PARAGANGLIA
The abdominal chromaffin bodies, the paraganglia aortica, or paraganglia lumbalia, are situated on each side of the abdominal aorta near the point of origin of the inferior mesenteric artery (figs. 1082, 1083). They are elongated, flattened, ovoid bodies, softer and greyer than the lymphatic glands and extremely variable in size.
They measure, as a rule, between 6 and 12 mm. in length, although occasionally as long as 30 mm. or as short as 1 mm. They may be connected by transverse bands in front of the aorta or occur as scattered nodules in this situation. They are intimately related to the aortic sympathetic plexus and at least one of them is uniformly found. They consist of a mass of chromaffin cells surrounded by a rich capillary plexus and contain many nerve fibres and nerve cells.
The coccygeal body [glomus coccygeum] is a small, spherical greyish-red body consisting of a median unpaired mass 2 to 3 mm. in diameter, single or divided into three to six connected nodules. It is placed immediately ventral to the tip
FiQ. 1084. — Coccygeal Gland, in Sittt. 1, Sacrum; 2, coccyx; 3, coccygeal gland; 4, middle sacral artery; 5, 6, sacral sympathetic; 7, ganglion impar.; 8, last sacral; 9, coccygeal nerve; 10, gluteus maximus; 11, ischio-coccygeus; 12, levator ani; 13, ano-coccygeal raphe. (Testut.)
of the coccyx, imbedded in fat and in relation with the terminal branch or branches of the medial sacral artery, with the ischio-coccygeal muscles, and fibres of the sympathetic nervous system (fig. 1084).
It is composed of groups of epithelial cells bound together by a mass of fibrous tissue and containing a plexus of sinusoidal capillary vessels in intimate relation with the cells. Numerous nerve fibres also enter the gland. It is not certain that the cells are chromaffin in character or that the coccygeal body has an internal secretion.
A. References for the skin and mammary gland. — General and topographic: Quain's Anatomy, 11th ed., vol. ii, pt. 1; Testut, Traits d'Anatomie Humaine, 4th ed .; Poirier-Charpy, Traits d'Anatomie, vol. v; Rauber-Kopsch, Lehrbuoh der Anatomie, 9th ed.; Bardeleben, Handbuch der Anatomie, vol. v, pt. 1; Merkel, Topographische Anatomie; Corning, Lehrbuoh der topographischen Anatomie. Development: Keibel and Mall, Human Embryology. Skin: Heidenhain, Anat. Hefte., vol. xxx; Kean (finger prints), Jour. Amer. Med. Assoc, vol. xlvii; Unna (blood and lymph), Arch. f. mikr. Anat., vol. Lx.xii; Botezat (nerves) Anat. Anz., vol. xxxiii. Nails: Branca, Annales de Dermat. et SyphQis, 1910; Mammary glands; Kerr, Buck's Ref. Hand. Med. Sci. (Breast) vol. 4, 1914.
B. References for the ductless glands. — General and topographic: Quain's Anatomy, 11th ed. ; Testut, Trait6 d'Anatomie Humaine, 4th ed., vol. iv; Poirier-Charpy, Traite d'Anatomie vol. iv.; Rauber-Kopsch, Lehrbuch der Anatomie, 9th ed.; Merkel, Topographische Anatomie; Corning, Lehrbuch der topographischen Anatomie, 3rd ed. Development: Keibel and Mall, Human Embryology. Spleen: Shepherd, Jour. Anat. and Physiol., vol. x.xxvii; Mall, Amer. Jour. Anat., vol. ii. Thyreoid: Marshall, Jour. Ansit. and Physiol., vol. xxix. Parathyreoids: Forsyth, Brit. Med. Jour., 1907; Rulison, Anat. Rec, vol. iii;Halsted and Evans, Annals of Surg., vol. xlvi. Thymus: Hammar, Erbge. d. Anat. u. Entwick., Bd., xix. Suprarenal glands: Gerard, Georges et Maurice, Bull. Mem. Soc. Anat. Paris, 1911, (6) T. 13; Ferguson, J. S., Amer. Jour. Anat., vol. v, 1905. Carotid body: Gomez, .L. P., Am. .tour. Med. Sci., vol. cxxxvi; Aortic paraganglia; Zuckerkandl, Verhandl. d. Anat. Gesell., 15th Versamm., 1901.
IN describing the clinical and topographical relations, the divisions of the bodywill be successively considered in the following order: headj neck, thorax, abdomen, pelvis, back, upper and lower extremities.
description of the cranium and the face.
Bony landmarks. — These should be studied with the aid of a skull, as well as on the hving subject. Beginning in front is the nasion, a depression at the root of the nose, and immediately above it, the glabella, a slight prominence joining the two supracihary arches. These points mark the remains of the frontal suture, and the junction of the frontal, nasal, and superior maxillary bones and one of the sites of a meningocele. In the middle line, behind, is the external occipital protuberance, or inion, the thickest part of the vault, and corresponding internally with the meeting-point of six sinuses. A line joining the inion and glabella corresponds to the sagittal, and occasionally the frontal, suture, the falx cerebri, the superior sagittal sinus, widening as it runs backward, and the longitudinal fissure of the brain. From the inion the superior nuchal hues pass laterally toward the upper and back part of the base of the mastoid processes, and indicate the first or socalled horizontal part of the transverse (lateral) sinus.
This vessel usually presents a varying curve upward and runs in the tentorium. The second or sigmoid portion turns downward on the inner surface of the mastoid, then forward, and lastly downward again to the jugular foramen, thus describing the double curve from which this part takes its name. In the jugular foramen the vessel occupies the posterior compartment; its junction with the internal jugular is dilated and forms the bulb. A line curved downward and forward from the upper and back part of the base of the mastoid, reaching two-thirds of the way down toward the ape.x, will indicate the second part of the sinus. The spot where it finally curves inward to the bulb would be about 1.8 cm. (J in.) below and behind the meatus. The two portions of the transverse sinus meet at the asterion laterally; at the entry of the superior petrosal sinus medially. The right transverse sinus, the larger, is usually a continuation of the superior sagittal sinus, and, therefore, receives blood chiefly from the cortex of the brain; the left, arising in the straight sinus, drains the interior of the brain and the basal ganglia. Each transverse sinus receives blood from the temporal lobe, the cerebellum, diploe, tympanic antrum, internal ear, and two emissary veins, the mastoid and posterior condylar.
About 6 . 2 cm. (2| in.) above the external occipital protuberance is the lambda, or meeting of the sagittal and lambdoidal sutures (posterior f ontanelle, small and triradiate in shape) . It is useful to remember, as guides on the scalp to the above two important points, that the lambda is on a level with the supraciUary ridges, and the external occipital protuberance on one with the zygomatic arches.
Below the external occipital protuberance, between it and the foramen magnum, an occipital, the commonest form of cranial meningoceles, makes its appearance. It comes through the median fissure in the cartilaginous part of the squamous portion of the bone.
1332 CLINICAL AND TOPOGRAPHICAL ANATOMY
The point of junction of the occipital, parietal, and mastoid bones, the asterion, is placed about 3 . 7 cm. (1| in.) behind and 1 . 2 cm. (| in.) above the centre of the auditory meatus (fig. 1085). It indicates the site of the posterior lateral fontanelle and just below it the superior nuchal line terminates. The bregma, or junction of the coronal, sagittal, and, in early life, the frontal suture (anterior f ontan elle, large and lozenge-shaped), lies just in front of the centre of a line drawn transversely over the cranial vault from one pre-auricular point to the other (fig. 1090) . The bregmatic f ontanelle normally closes before the end of the second year. The lambdoid fontanelle is closed at birth. The pterion, or junction of the frontal and sphenoid in front, parietal and squamous bones behind, lies in the temporal fossa, 3.7 to 5 cm. (IJ to 2 in.) behind the zygomatic process of the frontal, and about the same distance above the zygoma (fig. 1085). This spot also gives the position of the trunk and the anterior and larger division of the middle meningeal artery (fig. 1090), the Sylvian point and divergence of the limbs of the lateral (Sylvian) fissure, the insula (island of Reil), and middle cerebral artery. It, further, corresponds to the anterior lateral fontanelle. On the side of the skull the zygomatic arch, the temporal ridge, and external auditory meatus need attention. That important landmark, the zygomatic arch, wide in front where it is formed by the zygomatic (malar), narrowing behind where it joins the temporal, gives off here three roots, the most anterior marked by the eminentia articularis, in front of the mandibular (glenoid) fossa, the middle behind this joint, while the posterior curves upward and backward to be continuous with the temporal ridge. Within the zygomatic arch lie two fossae separated by the infra-temporal (pterygoid) ridge : above is the temporal, with the muscle and deep temporal vessels and nerves; below is the infra-temporal or zygomatic fossa, with the lower part of the temporal muscle, the two pterygoids, the internal maxillary vessels, and the mandibular division of the fifth. To the upper border of the zygomatic arch is attached the temporal fascia, to its lower, the masseter. Its upper border marks the level of the lower lateral margin of the cerebral hemisphere. A point corresponding to the middle root of the zygoma, immediately in front of the tragus, and on a level with the upper border of the bony meatus, is called the pre-auricular point. Here the superficial temporal vessels and the auriculo-temporal nerve cross the zygoma, and a patient 's pulse may be taken by the anaesthetist. The lower end of the central (Rolandic) fissure lies 5 cm. (2 in.) vertically above this point. The temporal ridge, giving origin to the temporal fascia, starts from the zygomatic process of the frontal, and becoming less distinct, curves upward and backward over the lower part of that bone, crosses the coronal suture, traverses the parietal bone, curving downward and backward to its posterior inferior angle. Here it passes on to the temporal, and passing forward over the external auditory meatus, is continuous with the posterior root of the zygoma. Below the root of the zygoma will be felt the temporo-mandibular joint, and when the mouth is opened, the condyle will be felt to glide forward on the eminentia articularis, leaving a well-marked depression behind.
The external auditory meatus, measured from its opening on the concha to the membrane, is about 2.5 cm. (1 in.) in length; if from the tragus, 3.7 cm. (1^ in.). Its long axis is directed medially and a little forward with a slight convex curve upward, most marked in its centre. Between the summit of this curve and the membrane is a sUght recess in which foreign bodies may lodge. The lumen is widest at its commencement, narrowest internally. To bring the cartilaginous portion in line with the bony, the pinna should be drawn well upward and backward. In the bony portion the skin and periosteum are intimately blended, thus accounting for the readiness with which necrosis occui's. The sensibility of the meatus is explained by the two branches sent by the auriculo-temporal nerve. The fact that the deeper part is supplied by the auricular branch of the vagus explains the vomiting and cough occasionally met with in affections of the meatus.
The anterior inferior angle of the parietal bone, and its great importance as a landmark, have already been noted. The posterior inferior angle of tliis bone (grooved by the transverse (lateral) sinus) lies a httle above and behind the base of the mastoid, on a level with the roots of the zygoma (fig. 1085). Just below and in front of the tip of the mastoid the transverse process of the atlas can be made out in a spare subject.
In front, the circumference of the bony orbit can be traced in its whole extent. The supraorbital notch lies at the junction of the medial and intermediate thirds of the supraorbital arch. When this notch is a complete foramen, its detection is much less easy. To its medial side the supratrochlear nerve and frontal arterd cross the supraorbital margin; like the supraorbital, this nerve and vessel lie, at
first, in close relation with the periosteum. The frontal artery is one of the chief blood-supplies to flaps taken from the forehead. Owing to the paper-like thinness of the bones on the medial wall of the orbit, e. g., lacrimal, ethmoid, and body of sphenoid, and the mobihty of the skin, injuries which are possibly penetrating ones, as from a slate-pencil, ferrule, etc., are always to be looked upon with suspicion. After a period of latency of symptoms, infection of the membranes and frontal abscess have often followed. Above the supraorbital margin is the supraciliary arch, and higher still the frontal eminence [tuber frontale].
cerebral topography and the hypophysis.
The scalp. — The importance of the scalp is best seen from an examination of its layers (fig. 1086). These are — (1) skin; (2) subcutaneous fat and fibrous tissue; (3) the epicranius (occipito-frontalis) and aponeurosis; (4) the subaponeurotic layer of connective tissue; (5) the pericranium.
The first three layers are connected and move together. The thick skin supported by the dense fibrous subcutaneous layer and epicranial aponeurosis, is well adapted to protect the underlying skull from the effects of trauma, and in this connection the mobility of the first three layers on the subaponeurotic areolar tissue is important. A scalp wound does not gape widely unless it involves the epicranial aponeurosis, in which case it involves the subjacent "dangerous area" of the scalp, so-called because pus in this laj^er maj^ spread widely underneath the scalp and even give meningeal infection by spreading through the diploic or emissary veins. In the process of scalping (whether performed by the knife or by the hair being caught in machinery), separation takes place at this subaponeurotic layer which is loose, delicate and devoid of fat.
The pericranium differs from periosteum elsewhere in that it gives little nourishment to the bone beneath, which derives most of its blood-supply from the meningeal vessels. After necrosis of the skull there is no tendency to the formation of an involucrum of new subperiosteal bone as in the long bones. The pericranium is firmly adherent to the sutures of the skull bones, so that any subpericranial effusion of blood or pus is limited by the sutures.
Of the vessels of the scalp, the arteries, arising in the anterior region from the internal, in the posterior from the external, carotid, are peculiar in their position. Thus they he superficial to the deep fascia, which is here represented by the aponeurosis (fig. 1086). From this position arises the fact that a large flap of scalp may be separated without perishing, as it carries its own bloodvessels. From the density of the layer in which the vessels run they cannot retract and are difficult to seize, haemorrhage thus being free. Finally, from their position over closely adjacent bone, ill-applied pressure may easily lead to sloughing. A practical point with regard to the veins is given below. The lymphatics from the front of the scalp drain into the anterior auricular and parotid, those behind into the posterior auricular, occipital and deep cervical nodes. The nerves are derived from all three divisions of the trigeminus, from the
Skull: diploic tissue
facial (motor) and also from three branches of the second and third cervical. The supply from the fifth explains the neuralgia in acute iritis, glaucoma, and herpes frontahs, and also the pains shooting up from the front of the ear in late cancer of the tongue.
The emissary veins. — These are communications between the sinuses within, and the veins outside, the cranium. Most of them are temporary, corresponding to the chief period of growth of the brain. Thus in early life, when the development of the brain has to be very rapid, owing to the approaching closure of its case, a free escape of blood is most essential, especially in children, with their sudden explosions of laughter and passionate crying!
The gravity of these emissary veins and their free communications with others are shown by the readiness Avith which they become the seat of thrombosis, and thus of blood-poisoning, in cranial injuries, erysipelas, infected wounds of the scalp, and necrosis of the skull. They include the following:
1. Vein through the foramen OEecum, between the anterior extremity of the superior sagittal sinus and the nasal mucous membrane. The value of this temporary outlet is well seen in the timely profuse epistaxis of children. Other more permanent communications between the skuD cavity arid nasal mucous membrane pass through the ethmoid foramina. The fact that the nasal mucous membrane is loose and ill-supported on the nasal conchas ( turbinate bones) allows its vessels to give way readily, and thus forms a salutary safeguard to the brain, warding off many an attack of apoplexy. 2. Vein thi-ough the mastoid foramen, between the transverse
THE BONY SINUSES 1335
(lateral) sinus and the posterior auricular and occipital veins. This is the largest, the most constant, and the most superficial of the emissary veins. Hence the old rule of applying blisters or leeches over it in cerebral congestion. 3. Vein through the posterior superior angle of the parietal between the superior sagittal sinus and the veins of the scalp. 4. Vein through the condyloid foramen between the transverse (lateral) sinus and the deep veins of the neck. 5. Vein through the hypoglossal canal between the occipital sinus and the deep veins of the neck. 6. Ophthalmic veins communicating with the cavernous sinus and the angular vein. These veins may be the source of fatal blood-poisoning, by conveying out of reach septic material, in acute periostitis of the orbit, or in osteitis, of dental origin, of the jaws. 7. Minute veins through the foramen ovale between the cavernous sinus and the pharyngeal and pterygoid veins. 8. Communications between the frontal diploic and supraorbital veins, between the anterior temporal diploic and deep temporal veins, and between the posterior temporal and occipital diploic veins and the transverse sinus. In addition to the veins specially mentioned, the scalp and sinuses communicate by numerous diploic veins, by those in the inter-sutural membrane, and thi'ough sutures before their obliteration, as already explained.
Structure of cranium. — Two layers and intervening cancellous tissue. Each layer has special properties. The outer gives thickness, smoothness, and uniformity, and, above all, elasticity. The inner is whiter, thinner, less regular — e. g. the depressions for vessels. Pacchionian bodies, dura mater, and brain. The diploe, formed by absorption after the skull has attained a certain thickness, reduces the weight of the skull without proportionately reducing its strength, and provides a material which will prevent the transmission of vibrations.
A blow on the head may fracture the internal layer only, the external one and diploe escaping. This is difficult to diagnose, and thus it is impossible to judge of the severity of a fracture from the state of the external layer. This may be whole, or merely cracked, while the-internal shows many fragments, which may set up meningitis or other mischief. It is usual to find more extensive splintering of the inner than of the outer layer (table).
The average thickness of the adult skull-cap is about 5 mm. (\ in.). (Holden.) The thickest part is at the external occipital protuberance, where the bone is often 1.8 cm. (| in.) in thickness. The thinnest part of the skull vault is over the temporal part of the squamous. The extreme fragility of the skull here is partly compensated for the by thickness of the soft parts; these two facts are always to be remembered in the diagnosis of a fracture of the skull here, after a slight injury. Other weak spots are the medial wall of the orbit, the cerebellar fossae, and that part of the middle fossa corresponding to the glenoid cavity.
Anatomical conditions tending to minimise the effects of violence inflicted upon the skull. — (1) The density and mobility of the scalp. (2) The dome-like shape of the skull. This is calculated to bear relatively hard blows and also to allow them to glide off. (3) The number of bones tends to break up the force of a blow. (4) The sutures interrupt the transmission of violence. (5) The inter-sutural membrane (remains of fcetal periosteum) acts, in early life, as a linear buffer. (6) The elasticity of the outer layer (table). (7) The overlapping of some bones, e. g. the parietal by the squamous; and the alternate bevelling of adjacent bones, e. g. at the coronal suture. (8) The presence of ribs, or groins, e. g. (a) from the crista galli to the internal occipital protuberance; (b) from the root of the nose to the zygoma; (c) the temporal ridge from orbit to mastoid; (d) from mastoid to mastoid; (e) from external occipital protuberance to th? foramen magnum. (9) Buttresses, e. g. zygomatic processes and the greater wing of the sphenoid. (10) The mobility of the head upon the spine.
Frontal. — When well developed, the frontal sinuses may reach 5 cm. (2 in.) upward and 3.7 cm. (1| in.) laterally, occupying the greater part of the vertical portion of the frontal bone. When very small, they scarcely e.xtend above the nasal process. In any case, they are rarely symmetrical. The average dimensions of an adult frontal sinus are 3.7 cm. (IJ in.) in height, 2.5 cm. (1 in.) in breadth, and 1.8 cm. (f in.) in depth. (Logan Turner.) The sinuses are separated by a septum. The posterior wall is very thin. Each sinus narrows downward into the infundibulum. This is 'deeply placed, at the back of the cavity, behind the frontal (nasal) process of the maxilla and near the medial wall of the orbit. Its termination in the middle meatus is about on a level -mth the palpebral fissure.' (Thane and Godlee.) Its direction is backward.
The communication of these sinuses with the nose accounts for the frontal headache, the persistence of polypi and ozsena, and the fact that a patient with a compound fracture opening up the sinuses can blow out a flame held close by.
To open the frontal sinus, while the incision which leaves the least scar is one along the shaved eyebrow, superficial laterally so to avoid the supraorbital nerve and vessels, running a little downward at the medial end, it is always to be remembered that, where the sinuses are little developed, this or a median incision may open the cranial cavity. To avoid this complication the sinus should always be opened at a spot vertically above the medial angle.
here much less grave in the adult than would otherwise be the case, the inner layer (table), if now separated from the outer, protecting the brain. Mr. Hilton showed that the absence of any external prominence here does not necessarily imply the absence of a sinus, as this may be formed by retrocession of the internal layer. In old people these sinuses may enlarge by the inner layer following the shrinking brain. Again, prominence of the supracOiary and frontal eminences does not necessarily point to the existence of a sinus at all, being due merely to a heaping up of bone.
The mastoid cells are arranged in two groups, of the utmost importance in that frequent and fatal disease, inflammation of the middle ear: — (A) The upper, or 'antrum,' present both in early and late life, horizontal in direction, closely adjacent to and communicating with the tympanum. (B) The lower, or vertical. This group is not developed in early life.
A. Tympanic antrum (fig. 1088). — This is a small chamber lying behind the tympanum, into the upper and back part of which (epitympanic recess) it opens. Its size varies, especially with age. Almost as large at birth, it reaches its maximum (that of a pea) about the third or fourth year. After this its size usually diminishes somewhat, owing to the development of the encroaching bone around
vertical cells
it. Its roof, or tegmen, is merely the backward continuation of the tegmen tympani. The level of this is indicated by the posterior root of the zygoma. 'The level of the floor of the adult skull at the tegmen antri is, on an average, less than one-fourth of an inch above the roof of the external osseous meatus; in children and adolescents, from one-sixteenth to one-eighth of an inch.' (Macewen.) In early life, when the bony landmarks, e. g. the suprameatal crest (fig. 1087), are little marked, the level of the upper margin of the bony meatus will be the safest guide to avoid opening the middle fossa.
The lateral wall of the antrum is formed by a plate descending from the squamous bone. This is very thin in early life, but as it develops by deposit under the periosteum, the depth of the antrum from the surface increases. Macewen gives the average of the depth as varying from one-eighth to threefourths of an inch. The thinness of the outer wall in early life is of practical importance. It allows of suppuration making its way externally — subperiosteal mastoid abscess. This will be facihtated by any delay in the closure of the petroand masto-squamosal sutures, by which this thin plate blends with the rest of the temporal bone. Further, by the path of veins running through these sutures or
their remnants, infection may reach such sinuses as the inferior petrosal. The sutures normally close in the second year after birth. Through the floor, the antrum communicates with the lower or vertical cells of the mastoid. This floor is on a lower level than the opening into the tympanum, and thus drainage of an infected antrum is difficult, fluid finding its way more readily into the lower cells. Behind the mastoid antrum and cells is the bend of the sigmoid part of the transverse (lateral) sinus, with its short descending portion (fig. 1087). The average distance of the sinus from the superior meatal triangle is 1 cm. (f in.). It may be further back; on the other hand, it may come within 2 mm. (y\ in.) from the meatus, and even overlap the outer wall of the antrum.
Fig. 1088. — The Mastoid Antrum and Cells. (Jacobson and Steward.) 1. Posterior root of zygoma forming the supramastoid or suprameatal crest and upper part of Macewen's triangle. 2. 3. Vertical cells of the mastoid. 4. Ridge on the inner wall of the tympanum, caused by the facial canal. 5. Fenestrse on inner wall of tympanum, indicated in shadow. 6. A deficiency present in the tegmen tympani, enlarged with a small osteotrite to emphasise the thinness of the roof of the antrum and tympanum. 7. Cells extending, in this case, even into the root of the zygoma.
The exact position of the antrum, a little above and behind the external auditory meatus is represented by Macewen's 'suprameatal triangle.' This is a triangle bounded by the posterior root of the zygoma above, the upper and posterior segment of the bony external meatus below, and an imaginary line joining the above boundaries (fig. 1087). "Roughly speaking, if the orifice of the external osseous meatus be bisected horizontally, the upper half would be on the level of the mastoid antrum. If this segment be again bisected vertically, its posterior half would again correspond to the junction of the antrum and middle ear, and immediately behind this lies the suprameatal fossa.' (Macewen.) When opening the antrum through this triangle, the operator should work forward and medially, so as to avoid the transverse sinus (fig. 1087) ; while, to avoid the facial nerve (fig. 10S7), he should hug the root of the zygoma and the upper part of the bony meatus as closely as possible. The level of the base of the brain will be a few lines above the posterior root of the zygoma (fig. 1089) and about 6 mm. (j in.) above the roof of the bony meatus. (Macewen.)
B. The lower or vertical cells of the mastoid are developed later than is the antrum, and vary much in their contents. The condition of the mastoid cells varies very widely. They may be numerous (fig. 1088) or few. In the latter case they are replaced by diploe, or by bone which is unusually dense, without necessarily any pathological change. Hence mastoids have been classified as pneumatic, diploetic, or sclerosed.
As part of the surgical anatomy of this most important region, the different paths by which infection of the tympanum and antrum may travel should be glanced at. The most important are: — (1) Upward: either by advancing caries or by infection of veins going to the superior petrosal sinus, or through the tegmina to the membranes; an abscess in the overlying temporal lobe, usually the middle and back part. (2) Backward : the transverse (lateral) sinus and cerebellum (abscess of the front and outer part of the lateral lobe) are reached in the same ways as those given above, the mastoid vein being the one chiefly affected here. Macewen has shown that the bony wall of the sinus, like those of the tegmina and the aqueduct of Fallopius, may be naturally imperfect. (3) Downward : where the vertical cells are well developed (fig. 929) mischief may reach the mastoid notch and cause deep-seated inflammation beneath the sternomastoid. (v. Bezold's abscess.) (4) Lateralward: the explanation of this, in early life, has been given above. (.5) Medialward : the facial nerve, or by the fenestra ovahs; the labyrinth is now in danger. When the internal ear and auditory nerve are affected, infection finds another path to the cerebellar fossa.
The sphenoidal sinuses are less important surgically, but these points should be remembered:— (1) Fracture through them may lead to bleeding from the nose, which is thus brought into communication with the middle fossa; (2) the communication of their mucous membrane with that of the nose may explain the inveteracy of certain cases of polypi and ozaena; (3) here and in the frontal sinuses very dense exostoses are sometimes formed. Before any operative attack on these sinuses is undertaken, their most important relations should be remembered. Thus above are the olfactory and optic nerves, the pituitary body, and front of the pons. Externally lie the cavernous sinus and superior orbital (sphenoidal) fissure. Below is the roof of the nose.
To make as clear as possible the points of practical importance which have, of late years, been put on a definite basis, and which the surgeon may have to recall and act upon at very short notice, cranio-cerebral topography will be spoken of under the following headings: A. Relation of the brain as a whole to the skull, B. Relation of the chief sulci and gyri to the skull. C. Localisation of the chief sulci and gyri. Before alluding to the above, it is necessary to say distinctly that the following surface-markings and points of guidance are only approximately reliable, for the following reasons: (1) In two individuals of the same age and sex the sulci and convolutions are never precisely alike. (2) The relations of the convolutions and sulci to the surface vary in different individuals. (3) That as the surface area of the scalp and outer aspect of the skull are greater than the surface area of the brain, and as the convexities do not tally, lines drawn on the scalp or skull cannot always correspond precisely to cerebral convolutions or sulci. It results from the above that when a definite area of the surface is said to correspond accurately in any individual to a definite area of the brain surface, this result has been correlated from many examinations; and that as surfacemarkings, shape, and processes of skull and arrangement of surface are all liable to variations in different individuals, the surgeon must allow for these variations by removing more than that definite area of skull which is said to correspond exactly to that part of the brain which he desires to expose.
A. Relation of the brain as a whole to the skull (figs. 1089, 1091). — To trace the lower level of each cerebral hemisphere on the skull, the chalk would start from the lower part of the glabella; thence the line representing the lower borders of the frontal lobe pursues a course, slightly curved upward, about 0.8 cm. (^ in.) above the supraorbital margin; next, crossing the temporal crest about 1.2 cm. (i in) above the zygomatic (external angular) process, it passes not quite horizontally but descending slightly to a point in the temporal fossa just below the tip of the great wing of the sphenoid (pterion), 2.5 cm. (1 in.) behind the zygomatic process. From this point the line of the level of the brain, now convex forward and corresponding to the anterior extremity of the temporal lobe, would dip down, still within the great wing of the sphenoid, to about the centre of the zygoma. Thence the line of the lower border of the temporal lobe would
travel along the upper border of this process about 6 mm. (J in.) above the roof of the external auditory meatus (fig. 1089), and thence just above the base of the mastoid and the posterior inferior angle of the parietal, and so along the linea nuchse suprema, and corresponding to the tentorium and horizontal part of the transverse (lateral) sinus, to the external occipital protuberance.
The upper margin of each hemisphere would be represented by a line drawn from just below the glabella, sufficiently to one side of the middle line to allow for the falx and superior sagittal sinus, to one immediately above the superior external occipital protuberance and inion.
isation of the chief sulci and gyri. These headings will be taken together.
It will be well first to indicate the position of the chief sutures which mark off the parietal bone, under which lies that part of the brain which is most important to the surgeon — the motor area. The upper limit of the bone will be indicated by the line already spoken of as giving the upper margin of the hemisphere — the sagittal line, or Sagittal suture. The anterior limit of the parietal bone, formed
s.M. Supraciliary margin of the cerebrum, i.l.m. Infero-lateral margin of the cerebrum. L.s. Position of highest part of the arch of the transverse sinus. R. Central sulcus (Fissure of Rolando), s^. Anterior horizontal limb of lateral fissure, s^ Anterior ascending limb of lateral fissure, s^ Posterior horizontal limb of lateral fissure, p.b. Opercular portion of the inferior frontal convolution, p.t. Triangular portion of the inferior frontal 'convolution. P.O. Orbital portion of the inferior frontal convolution.
by the coronal suture, may be traced thus : The point where it leaves the sagittal suture (the bregma) will be found by drawing a line from a point just in front of the external auditory meatus (the pre-auricular point) (fig. 1085) straight upward on to the vertex; from this point a line drawn downward and forward to the middle of the zygomatic arch would indicate that of the coronal suture. Under this suture lie the posterior extremities of the three frontal convolutions; for the frontal lobe lies not only under the frontal bone, but extends backward under the anterior part of the parietal, the central sulcus (fissure of Rolando) , which separates the frontal from the parietal lobe, lying from 3.7 to 5 cm. (1| to 2 in.) behind the coronal suture at its upper extremity and about 2.5 cm. (1 in.) at its lower.
The squamoso-parietal suture, which marks the lower border of the anterior two-thirds of the parietal bone, is not so easy to define, owing to the irregularity and variations of its curve. Its highest point is usually 4.3 cm. (If in.) above the zygoma.
The lambdoid suture, which forms the posterior boundary of the parietal bone, will be marked out by a line which starts from a point (lambda) about 6.2 cm. (2i in.) above the external occipital protuberance, and runs downward and forward to a point on a level with the zygoma, 3.7 cm. (IJ in.) behind and 1.2 cm. (J in.) above the centre of the meatus.
Lateral (Sylvian) fissure (fig. 1089). — The point of appearance of this, on the outer side of the brain, practically corresponds to the pterion (p. 1332, fig. 1085) — a point which lies in the temporal fossa, about 3.7 cm. (1| in.) behind the zygomatic process and about the same distance above the zygoma. From this point the lateral fissure, which here separates the frontal and parietal from the temporal lobe, runs backward and upward, ascending gently, at first in the line of the squamo-parietal suture, then crossing this suture about its centre and thence, ascending more rapidly, it climbs up to the temporal ridge, to end 1.8 cm. (f in.) below the parietal eminence. Its termination is surrounded by the supramarginal convolution, to which the parietal eminence corresponds with sufficient accuracy. Such being the surface-marking of the chief or posterior horizontal limb of the lateral fissure (s^, fig. 1089), it remains to indicate briefly the two shorter limbs which bound the inferior frontal convolution, which, on the left side, contains the centre for speech (Broca's convolution), and corresponds to a point l3ang three fingers' breadth vertically above the centre of the zygomatic arch. (Stiles.) Of these, the anterior horizontal (s^, fig. 1089) runs forward across the termination of the coronal, just above the line of the sphenoparietal suture. The ascending limb (s^, fig. 1089) runs upward for about
The central sulcus (fissure of Rolando). — This most important fissure, in front of which, in the precentral convolution of the frontal lobe, lie the motor centres for the opposite side of the body, is situated under the parietal bone. It may be marked out with sufficient precision in the following way (Thane): The sagittal line, from glabella to external occipital protuberance, is bisected, and a point 1.2 cm. (Jin.) behind the centre represents the superior Rolandic point. From this point a line drawn downward and forward 9 cm. (3| in.) long, at an angle of 67|° with the sagittal line (i. e., | of a right angle) will represent the central sulcus. The lower extremity of this line is known as the inferior Rolandic point.
This method is open to the objection that it only apphes to the average adult skull, and not to skulls of all sizes. To obviate this difficulty the method of Kronlein may be employed in addition (fig. 1085). A base line BL is drawn through the lower border of the orbit and the upper border of the external acustic meatus. Parallel to this an upper horizontal Une UH is marked out at the level of the upper margin of the orbit. Three hues vertical to the base line are now drawn, (1) at the posterior border of the mastoid process MRi (2) through the condyle of the lower jaw (CR2), and (3) from the mid-point of the zygoma (ZS). The point Ri, where the first vertical joins the sagittal sutiu'e is the superior Rolandic point. The point S where the third vertical ZS cuts the line UH marks the junction of the three hmbs of the lateral fissure. A line joining Ri and S will cut the second vertical CR2 at the inferior Rolandic point, Rj.
Some further points in the surgical anatomy of the cranium must be referred to: — The middle meningeal artery. This vessel, entering the middle fossa by the foramen spinosum, grooves the great wing of the sphenoid and divides into two branches. The anterior grooves the anterior inferior angle of the parietal bone, and is then continued upward and slightly backward between the coronal suture and central sulcus (fig. 1090), almost to the vertex; the posterior branch takes a lower level, running backward under the squ.imous bone to supply the parietal and anterior part of the occipital bones. If a skull, bisected antero-posteriorly, be held up to the light, it will be seen how thin are the bones over the chief branches of this vessel, thus accounting for the slight violence sometimes sufficient to rupture it. The groove it occupies in the parietal is sometimes converted into a canal. A wounded artery retracting here may be very difficult to secure. The veins which accompany the artery and which lie lateral to it
in the groove are thin-walled and sinus-like before they open into the spheno-parietal sinus, another explanation of the obstinacy of this haemorrhage. According to the point of rupture, three hsematomata should be remembered (Kronlein), anterior or fronto-temporal; middle, or temporo-parietal; and posterior, or parieto-occipital. The first two are much the most frequent, and exposure of the pterion, with free removal of the adjacent bone, will suffice for dealing with them.
Drainage of the lateral ventricle. — (1) Where the anterior fontanelle is closed, Poirier and Keen have opened the inferior cornu through the middle temporal convolution, the pin of the trephine being placed 3.1 cm. (IJ in.) behind the external auditory meatus, and about the same distance above Reid's base-line which is drawn from the lower margin of the orbit through the mid-point of the external auditory meatus. The needle should here be directed to a point
about 5 cm. (2 in.) above the opposite ear. (2) Kocher's point for draining the lateral ventricle is taken over the frontal lobe 2.5 cm. from the median line and 3 cm. in front of the upper Rolandic point. The needle is passed downward and a little backward to a depth of 4 or 5 cm.
Up to this point the outside of the cranium has been mainly considered; it remains to draw attention to some of the chir.f points in the sjirgical anatomy of the interior, especially ot the base. The three fossae are of paramount importance in fracture. In the anterior fossa the delicacy of parts of the floor, the connection of this with the nose and orbit, and the exact adaptation of its irregular surface to that of the frontal lobes, no 'water-bed' intervening, are the chief points. Thus the slightness of a fatal fissure, the frequent presence of bruising after a blow perhaps on the occiput, which has been considered to have caused only concussion, the characteristic palpebral hemorrhage, and the infection of a fracture here are all explained, together with the possibility and gravity of a fracture here from a severe blow on the nose. In the middle fossa the frequency of fractures is explained by the facts that while here, as in the other fossae, a fracture often radiates down from the vertex, the overlying vault being a region often struck, the base is weakened by numerous foramina and fissures. Further, the resisting power of the petrous bone must be lessened by the cavities for the internal ear, the carotid, and, to a less degree, by the jugular fossa. For fluids to escape through the external meatus, the dura, the prolongation of the arachnoid into the internal meatus, the membrani tympani, and probably the internal ear, must all be injured. The presence of the middle meningeal artery (fig. 1090) and the cavernous sinus in this fossa must also be remembered, especially in such operations as that on the Gasserian ganglion. Posterior fossa : It is not sufficiently recognised that fractures here are, owing to the anatomy of the parts, in some respects the most important of all. It is here that a small fissure-fracture, ultimately fatal, with severe occipital and frontal bruising and some intradural hemorrhage, has been so often overlooked, especially in the drunken. This is explained by the supposed strength of the bone, this being really very thin in places, by the thickness of the soft parts, and the abundance of hair. Further, there is no very apparent escape of cerebral contents as in the anterior and middle fosse. Blood, etc., may trickle into the pharynx far back, or a deep-seated eochymosis coming up after two days, under the muscles about the mastoid process, may call attention to the damage within.
Dura mater. — The outer layer of this membrane acts as a periosteum, by bringing bloodvessels to the bone while the inner layer supports the brain. The influence of its partitions and its damping effect on vibrations is great in blows on the head. Its varying adhesions, according to site and age, must be remembered. Thus while it is intimately connected over the base with its adhesions to the different foramina, it is more loosely connected with the vault, as is shown in middle meningeal hemorrhage. In early and later life the closeness of its connection with the bones is also more marked. It is united to the inter-sutural membranes.
Finally, the existence of the cerebro-spinal fluid with its power of lessening the evil of vibrations and its aid in regulating infra-cranial pressure, must be borne in mind. The chief collections, in which the subarachnoid meshwork is almost absent, are met with in front and behind the medulla. That in front, also lying under the pons, Hilton's 'water-bed,' sends a prolongation forward to the optic chiasma, but does not extend under the frontal or temporal lobes. The collection behind lies between the medulla and under surface of the cerebellum. Here, by the foramen of Magendie, the intra-ventricular cavities communicate with the subarachnoid space of the spinal cord.
THE HYPOPHYSIS CEREBRI
The hypophysis (pituitary body) which has now become of great clinical importance, consists of a pars anterior and pars intermedia derived from the buccal ectoderm, and a posterior pars nervosa formed by a downgrowth from the floor of the third ventricle. The gland lies in the fossa hypophyseos of the sphenoid bone, and an enlargement of it, apart from general skeletal and nutritional effect due to anomalies of its internal secretions, will cause pressure on the cavernous sinus on each side, and on the optic chiasma above. It will also expand the fossa hypophyseos, pushing down its floor at the expense of the sphenoidal air sinus. Such enlargements may be detected by lateral radiograms. The normal size of the adult hypophyseal fossa (fig. 1097) is 10-12 mm. from before backward and 8 mm. from above downward (Keith).
The hypophysis may be exposed surgically either by turning the nose to one side, and removing the upper part of the septum and floor of the sphenoidal sinus, or by Cushing's method, in which a sublabial incision is made in the vestibule of the mouth, and through it the mucosa is then separated from each side, of the nasal septum back to the sphenoidal sinus. A strip of septum is removed, and also the floor of the sphenoidal sinus, after which the hypophyseal fossa is opened and the gland e.xposed (fig. 1097).*
and zygoma — can be readily traced. The last mentioned and the glabella are alluded to on pp. 1331 and 1332; and the canine fossa should be identified as one of the antral routes. The delicacy, laxity, and vascularity of the skin are of great importance in all operations, while the abundance of large gland orifices accounts for the frequency of lupus here.
Arteries. — The supraorbital artery can be felt beating just above its notch (junction of medial with lateral two-thirds of supraorbital margin); the little frontal artery is of importance, as it nourishes the flap when a new nose is taken from the forehead; the superficial temporal, accompanied by the auriculo-temporal nerve, can be felt where it crosses the root of the zygoma just in front of the tragus, its anterior branch about 3.1 cm. (1| in.) above and behind the zygomatic process of the frontal; the occipital, accompanied by the great occipital nerve (fig. 450), pulsates to the medial side of the centre of a line drawn from the occipital protuberance to the mastoid process; the posterior auricular, rather deeply, between the auricle and the mastoid process. The external carotid lies behind the ascending
ramus of the jaw. The external maxillary (fig. 1093) crosses the jaw just in front of the masseter; if divided, both ends must be secured here. It can be felt again a little behind the angle of the mouth, just beneath the mucous membrane (it here gives off the labial branches, which can also be felt, lying deeply, if the lip is taken between the finger and thumb) ; and again by the side of the nose, as it runs up to Ithe angulusoculi. The small angular branch is, from its position, always troublesome to secure. To trace the course of the external maxillary artery a line should be drawn from a point a little above and lateral to the tip of the great cornu of the hyoid to the lower part of the anterior border of the masseter, and thence to one lateral to and above the angle of the mouth, and so onward, lateral to the angle of the nose, up to the medial angle. The anterior facial vein takes a straight course behind the tortuous external maxillary artery. The absence of valves and its communication by the angular and ophthalmic veins with the cavernous sinus, and, by the deep facial, with the pterygoid plexus, are of grave importance in infective thrombosis. The external jugular vein will be mentioned later.
opens into the mouth opposite the second molar tooth. The level of the duct, somewhat inconstant, would be usually about a finger^s breadth below the zygoma. It is accompanied by the transverse facial artery above, and the infraorbital branch of the facial nerve below.
The sheath of the parotid, continuous with those of the masseter and sterno-mastoid, is strong enough to cause most exquisitely painful tension when inflammation of the gland is present, and, together with the presence of deep processes of the gland in connection with the
mandibular (glenoid) cavity and styloid process, to explain the deep burrowing of pus which may take place into the pharynx and pterygoid region. The relation of the capsule to growths, innocent or malignant, of the parotid is also important (See figs. S65, 1092).
The parotid region would be thus mapped out (fig. 1096). Above by the posterior two-thirds of the zygoma; below, by a line corresponding to the posterior belly of the digastric (fig. 1096) ; behind, are the external auditory meatus, mastoid, and sterno-mastoid. In front the gland and socia parotidis overlap the posterior part of the masseter, to a variable degree (fig. 1096).
THE FACE 1345
Sensory nerves. — -The cutaneous nerve areas of the face are shown in fig. 774. The supraorbital nerve, the main sensory branch of the ophthalmic, emerges from the orbit with its companion artery through the notch (occasionally a foramen) at the junction of the medial third and lateral two-thirds of the supraorbital margin. A line drawn from the supraorbital notch downward across the interval between the bicuspid teeth will cross the infraorbital foramen from which emerges the infraorbital nerve, the main terminal division of the maxillarj^, at a point 1 cm. below the orbital margin. The mental foramen, the point of exit of the mental nerve, a branch of the inferior alveolar, is found on a prolongation of the same line midway between the upper and lower margins of the mandible in the adult. In the infant in whom the alveolar element of the jaw is relatively large, the mental foramen is nearer the lower margin, while in the edentulous jaw of old age it is found much nearer the upper margin.
In trephining to expose the inferior alveolar (dental) nerve, one of the common seats of neuralgia and one in which a peripheral operation is justified from the results, the ascending ramus is opened midway between its anterior and posterior borders, on a level with the last molar.
The semilunar ganglion lies at a depth of 5.5-6 cm. (2i in.) upder the eminentia articularia at the base of the zygoma. In exposing it for the purpose of excision for intractable neuralgia the following structures are encountered: (1) Skin and superficial fascia with branches of the superficial temporal artery; (2) temporal fascia and muscle with deep temporal vessels; (3) squamous bone and great wing of sphenoid, which are trephined, the floor of the middle fossa being gouged away ; (4) middle meningeal vessels and dura mater. By elevating the dura mater and superimposed temporal lobe, and securing the middle meningeal artery, the ganglion is exposed, lying in a separate compartment [cavum Meckelii] of the dura, which contains cerebrospinal fluid. The motor nerve of the muscles of mastication lies on the lower and medial aspect of the ganglion, and should not be divided.
Injection of the mandibular nerve with alcohol, by means of a long stout hypodermic needle is practised in cases of intractable neuralgia as an alternative to excision of the semilunar ganglion. A vertical line is drawn on the cheek downward from the junction of the posterior and middle thirds of the zygomatic arch, and the needle is entered on this line at a point 1.5 cm. from the lower border of the zygoma. It is directed upward and medially so as to pass through the lowest part of the mandibular notch. If the mouth is opened the notch is depressed and more room gained. The needle impinges first against the inferior surface of the great wing of the sphenoid bone, and when the point is lowered a little it engages in the foramen ovale at a depth of 4-4,5 cm. In most cases the needle can be passed thi'ough the foramen ovale into the semilunar gangUon. (Harris.)*
The maxillary nerve may be injected by passing a needle along the floor of the orbit from its infero-lateral angle in a direction backward and sUghtly medially to the foramen rotundum which lies 4.5 cm. from the surface.
Facial nerve. — In the petrous bone the course of this nerve is first outward and forward, then, having entered the facial canal, backward and downward along the medial wall of the tympanum, above the fenestra ovalis. Emerging from the stylo-mastoid foramen the nerve takes first the line of the posterior belly of the digastric, running forward and a little downward from the anterior border of the mastoid where this meets the auricle. (Godlee.) Entering at once the posterior part of the parotid, it crosses the neck of the mandible at the level of the lower border of the tragus.
The frequent paralysis of this nerve may thus depend upon — (1) cerebral causes; (2) disease of or injm-y to the petrous portion; (.3) affections after its exit— BeU's paralysis. A diagnosis may be arrived at by attention to the following. In cerebral disease the lower part of the face is chiefly affected, the eyelids usually escaping. In aU the other forms the whole side of the face is paralysed. Hemiplegia of the opposite side of the body and paralysis of the sixth nerve are usually present. In petrous paralysis, owing to involvement of the chorda tympani, there may be interference with the saliva and taste, affecting especially the anterior part of the tongue. The auditory nerve may also be affected. Here and in (3) there will be a histor}' of disease or injury. In complete paralysis the smooth side of the face and forehead, the absence of power of expression, to frown, to blow, or whistle, the open eyelids and epiphora, and subsequent liability to mischief in the cornea, the di-opping of the angle of the mouth and dribbling of saUva, the interference with mastication from paralysis of the buccinator, are the chief points.
Mandible. — Dislocation of the temporo-mandibular joint is referred to on p. 217. In the usual dislocation, from muscular action, the jaw is suddenly brought forward against the anterior part of the capsule, which tends, bj!- the action of the depressors, to give way; the elevators then pull up the mandible, a sequence that must be remembered in reduction. In the commonest fracture of
the mandible — unilateral, near the mental foramen — the larger anterior fragment will be pulled by the depressors downward and medially, the smaller posterior one upward and usually lateral to the other fragment.
Maxilla. — The boundaries of the maxillary sinus (antrum) are of much importance. The base of this irregularly pyramidal cavity corresponds to the middle and inferior meatuses on the lateral wall of the nose; toward the upper and back part is the opening into the middle meatus. The apex runs laterally toward the zygomatic process. The roof is formed by the orbital plate with the infraorbital nerve and vessels anteriorly; the floor by the junction of the alveolar arch, carrying the first molars (and often the bicuspids), with the hard palate. It may be pierced by the roots of the second bicuspid or first and second molar teeth. Anteriorly, the antrum is bounded by the canine fossa; posteriorly it is in relation with the zygomatic fossa. The cavity, present at birth, increases gradually up to the twelfth year.
The chief paths of infection are through the teeth (especially the first and second molar), the nose, and frontal sinus. The obstinacy of inflammation here is explained by the site of the opening, high up on the medial wall, and thus inadequate drainage, by the imperfectly multilocular cavity of the interior and its rigid walls. The chief sites for opening the antrum are — (a) thi'ough the sockets of the first or second molars; (b) through the canine fossa, after the reflection of mucous membrane has been detached, midway between the roots of the teeth and the infraorbital foramen (this path gives more room) ; (c) through the inferior meatus of the nose.
THE ORBIT AND EYE
The bony orbit is a pyramidal fossa with its base at the orbital margin and its apex at the optic foramen. The medial walls of the two orbits are approximately parallel, but the lateral walls diverge as they are traced forward and lie at right angles to each other. The thin floor which is formed mainly by the maxilla and corresponds to the roof of the maxillary sinus, is readily destroyed by growths extending up from the sinus and in the process pressure on the infraorbital nerve is apt to cause pain referred to the cheek. The roof formed by the orbital plate of the frontal bone is also thin, and foreign bodies thrust into the orbit may perforate it and enter the frontal lobe of the cerebrum. The medial wall is chiefly constituted by the lacrimal and lamina papyracea of the ethmoid, both very thin bones. This wall is readily destroyed by malignant growths of the nose.
Injuries of the medial wall such as may be associated with fractures of the nose bring the ethmoidal air cells into communication with the cellular tissue of the orbit. The latter may thus be distended with air on attempting to blow the nose.
The lateral wall is formed in its anterior third by the zygomatic bone, which separates the or"bit from the zygomatic fossa. The posterior two-thirds formed by the sphenoid bone separate the orbit from the temporal lobe of the brain in the middle cranial fossa. The orbit communicates with the cranimn by the optic foramen, which transmits the optic nerve and ophthalmic artery and the superior orbital fissure through which pass all the other vessels and nerves of the orbit.
In cases of fracture of the base of the skuU involving the anterior clinoid process, a traumatic communication (arterio-venous aneurysm) may be formed between the internal carotid artery and cavernous sinus, behind the apex of the orbit, giving rise to pulsating exophthalmos.
The orbital margin is larger in the transverse than in the vertical direction, and consequently there is more space on either side than above and below between it and the eyeball which is nearly spherical. The eyeball lies nearer to the medial than to the lateral margin and hence foreign bodies more commonly penetrate the orbit to the lateral side of the eye.
which foreign bodies may be hidden for a considerable time.
The structure of the eyelids. — The different layers are of much practical importance. (1) The skin is delicate and fatless, and contains pigment, the object of this being to protect the eye from bright light. It helps to explain the 'dark circles' of later life. (2) Areolar tissue. Owing to its looseness and delicacy, this is very liable to infiltration, as in oedema and erysipelas. (3)
Orbicularis. Paralysis of this, tiie palpebral portion, leads to epipiiora, tiie puncta being no longer kept in their normal baclcward direction against the conjunctiva. (4) Palpebral fascia, reaching from the orbit to the tarsal cartilage. This is usually strong enough to prevent haemorrhage, due to fractured base of skull, becoming subcutaneous. (5) Levator palpebr^e. (6) Tarsal plate; in reality, densely felted fibrous tissue. (7) Tarsal (Meibomian) glands, lashes, and sebaceous follicles.
I Localised inflammation starting in any of these last three structures, especially the last, will cause a 'stye.' The frequency with which the lid-border is the seat of that most troublesome chronic inflammation, blepharitis, and its result, 'blear eye,' is e.xplained by these anatomical points. Its circulation is terminal and slow; half skin and half mucous membrane, it is moister and more liable to local irritation than the skin; while its numerous glands readily participate in any inflammation.
Opening of duct of tarsal gland
(8) The conjunctiva. To trace this important membrane, the lids should be everted, when the following will be noted. The conjunctiva over the tarsal part of the lid is closely adherent, and through it a series of nearly straight, parallel, light yellow lines and granules, the tarsal glands, can be seen. Owing to their position here (fig. 1094) and to avoid scarring, a tarsal cyst is always opened on its conjunctival surface.
Beyond the tarsi, the palpebral conjunctiva is thicker and freely movable owing to the abundant lax submucous tissue. Underlying vessels are visible here. Leaving the eyelid the conjunctiva is reflected onto the eyeball at the fornix. Into the lateral part of the upper fornix open the ducts of the lacrimal gland. The bulbar conjunctiva is continued over the front of the ej^eball to the corneal margin. It is thin and contains fine vessels which are distinguished from subjacent episcleral vessels by the fact that they move with the conjunctiva.
These conjunctival vessels, derived from the lacrimal and palpebral arteries, become veryvisible in conjunctivitis. In deep inflammation affecting .the iris and ciliary body, the episcleral branches of the anterior ciliary arteries (which are derived from the muscular and lacrimal arteries) become engorged and are visible as a pink circumcorneal zone of congestion, deeply situated under the conjunctiva. These branches take a large share in the nutrition of the cornea, and are responsible for the vascularity of pannus and the 'salmon patches' of interstitial keratitis.
The conjunctival nerves for the upper lid and bulbar part of the membrane, and the nerves to the cornea, are supplied by the ophthalmic division of the trigeminal. The maxillary division of this nerve sUpphes the lower palpebral conjunctiva.
The differing structure of the palpebral and ocular portions has important bearings. Thus the palpebral conjunctiva is thick, highly vascular and sensitive. To this vasovilarity we owe the chemosis, or hot, red, tense swelling of purulent ophthalmia. The exquisite suffering of the same disease, or that caused by a foreign body, is explained by the numerous nerve-papillje and endbulbs. To the thickness and abundance of the connective tissue are due the contraction and permanent thickening which may occur in granular lids. The so-called granulations, met with in this disease on the palpebral conjunctiva, are really little nodules of hypertrophied lymphoid follicles, or mucous glands, which abound here.
five-sixths of the eyeball, and is intimately connected with the sheaths of the extrinsic muscles and through the check ligaments with the orbital walls. Together with the conjunctiva it must be opened in the operation of tenotomy for strabismus, and after division of a rectus tendon the muscle retains some control over the eye through its connection with the fascia bulbi. In enucleation of the eyeball both conjunctiva and fascia bulbi are divided around the cornea, where they are intimately blended. In removal of the upper jaw the attachment of the suspensory ligament of this fascia must always be left if possible, for otherwise the eyeball will tend to fall forward and the cornea suffer from its exposure (Lockwood). Finally the cavity between the two layers of the capsule is continuous with the extensions of the cerebral membranes along the optic nerve, i. e., with the subarachnoid space.
For an account of the intrinsic and extrinsic muscles of the eye the reader is referred to the section on the Eye. Reference may be made here, however, to the part played by certain fibres of the cervical sympathetic system. Emerging from the cord at the fh-st and second thoracic segments, the communicating fibres pass up the sympathetic chain in the neck to cell stations in the superior cervical ganglion. Thence continuing onward tltrough the carotid canal and superior orbital fissure, they supply (1) the dilator muscle of the u'is, (2) the unstriped muscle element in the eyelids, and (3) smooth muscle fibres, deoribed by Sappey, in the check ligaments and fascia bulbi. Paralysis of the cervical sympathetic nerve in the neck, usually in its lowest part, by trauma or the pressure of a malignant growth, causes therefore (1) narrowing of the pupil, (2) narrowing of the palpebral fissure (pseudo-ptosis), and (3) enophthalmos.
The lacrimal gland lies in a hollow at the supero-lateral angle of the orbit, protected by the zygomatic process of the frontal bone. It is not palpable normally. Its lower or palpebral portion rests on the lateral third of the fornix
the lids must be previously everted. The puncta are kept open by a minute fibrous ring.
Each is situated on a minute papilla at the junction of the medial and straight third of the lid with the lateral curved two-thirds. Close to the medial angle, in addition to the puncta and papillae, should be noted the caruncula lacrimalis, with its delicate haii's, and the plica semilunaris, which corresponds to the third eyelid of certain birds.
The lacrimal sac is a most important part of the lacrimal apparatus, from its disfiguring diseases; it lies in a bony groove, between the nasal process of the maxilla and the lacrimal bone. The medial palpebral ligament crosses it a little above its centre (fig. 1095) . Thus two-thirds of the sac are below the ligament, and in suppuration the opening is made below it also. The angular artery ascends on the nasal side of the sac.
The manipulation of a probe along the lacrimal passages should thus be practised: — the lower lid being drawn laterally and downward by the thumb, the probe is passed vertically into the punctum, then turned horizontally and passed on till it reaches the medial waU of the sac. It is then rotated somewhat forward, raised vertically, and pushed gently along the duct downward, and a little lateralward and backward, till the floor of the nose is reached, the operator aiming, as it were, for the site of the first molar tooth. The naso-lacrimal duct extends from the lower end of the lacrimal sac to the inferior meatus of the nose and is about 1 . 2 cm (J in.) in length.
If the tongue be raised, the under surface is seen to be smooth and devoid of papillse. In the middle line is the frenulum. When division of this is really required in tongue-tie, the scissors should be kept close to the bone, in order to avoid the ranine vessels.
Of these, the veins can be seen just to one side; the arteries are close by, but deeper. Farther out are two more or less distinct fringed folds, the plica; l fimbria tse, running from behind forward and, like the frenulum, disappetiring before the tip. Between these and the frenulum are the small apical mucous glands of Nuhn or Blandin. Farther back, at the junction of the mucous membrane and the alveoli, are two other projections of the mucosa, the sublingual; under these are the sublingual glands, the ranine veins, and, more deeply, Wharton's duct and the termination of the lingual nerve. The majoritj' of the ducts of the sublingual gland (Rivinian) open on the sublingual ridges. A single larger one, Bartholin's, opens with that of Wharton, or close to it, on either side of the frenulum (fig. 1096). Dilatation of one of the Rivinian ducts, more frequently dilatation of a muciparous gland — and, much more rarelj', dilatation of Wharton's duct — constitutes a 'ranula.'
The submaxillary gland can be felt nearer the angle of the jaw, lying between its fossa and the mucous membrane, especially if pressure is made from outside. The attachment of the genio-glossi can be felt behind the symphysis: the division of the muscles allows the tongue to come well out of the mouth; but when both have to be divided, the tongue loses much of its steadiness, and may easily fall
back over the larynx during the administration of the anaesthetic or, later on, in sleep. It should therefore be secured forward for a while with silk. For the same reason, in removal of one-half of the mandible, part of this muscular attachment should always be left, if possible.
Turning now to the dorsum of the tongue, this shows two distinct parts: one, the anterior two-thu'ds, the buccal, is rich in papiUic; the other, the posterior, the pharyngeal, contains abundant lymphoid follicles like the tonsil. This part possesses peculiar sensibiUty, as shown by movements of tongue and palate when a depressor is placed too far back. The two parts are separated by the v -shaped arrangement of the vallate papillEe, with the apex turned backward. Immediately behind the apical vallate papilla is a small pit, the foramen cEecum which represents the upper remains of the thyreoglossal tract, and may be the seat of lingual thyreoid growths. While the tongue is mainly a muscular organ, the fine fatty connective tissue in the septum and between the muscular bundles is the seat of that dangerous condition acute glossitis, and of gummatous infiltration. While the mouth is widely open, the pterj^go-mandibular ligament can be seen and felt beneath the mucous membrane, behind the last molar tooth. Just below and in front of the lower attachment of this ligament the lingual nerve can be felt lying close to the bone below the last molar. The simplest and surest method of dividing the nerve here, to give relief from pain in incurable carcinoma of the tongue, is to draw the tongue out of the mouth and expose the nerve where it lies superficially under the mucous membrane thus made prominent between the side of the tongue and the gums, the centre of the incision
Behind the last molar tooth can be felt the coronoid process, and higher up, just behind and medial to the tooth, the pterygoid hamulus of the sphenoid. This process is a landmark to the site of the greater palatine foramen, which lies just in front of it, and which transmits the greater palatine branch of the descending palatine artery, together with the anterior palatine nerve. The vessel and nerve run forward in grooves on the lower surface of the palatine process of the maxilla, giving off anastomosing branches toward the middle line, and join at the incisive foramen with the nasopalatine artery.
Their position must be remembered in raising the flaps during the operation for closure of a cleft in the hard palate. To ensure the vitality of the flaps the incisions must be made lateral to the vascular arch, close to and pai'allel with the upper alveolus, and should not extend beyond a point opposite to and just medial to the last molar tooth, for fear of encroaching upon the posterior palatine canal.
When the teeth are clenched, there is still a space, communicating between the mouth and pharynx behind the molar teeth, which admits a medium-sized catheter. When a patient breathes deeply through the mouth and the head is thrown back, the soft palate is raised, the pillars (arches) separated; the uvula and fauces, with the anterior and posterior pillars, with their attachments, the tonsils, and the back of the pharynx are exposed.
This portion of the pharyngeal mucous membrane would lie over the lower part of the second and the upper part of the third cervical vertebrae, the anterior arch of the atlas corresponding to the level of the posterior nares, and the body of the epistropheus (?ixis) to the level of the soft palate (fig. 1097). If a finger be introduced past the soft palate to this part of the spine and turned upward and downward, it is possible, with the aid of an anfesthetic, to examine the upper four or five and, in children, six vertebrse, as far as the anterior surfaces of their bodies. 'The part of the column which is accessible to a straight instrument introduced through the mouth is very hmited, extending, in the adult, from the lower border of the axis to the middle or lower part of the fourth cervical vertebra; in the child, owing to the small size of the face, it comprises the bodies of the axis and of the third cervical vertebra.' (Thane and Godlee, from Chipault.) The distance from the incisor teeth to the commencement of the oesophagus at the cricoid cartilage is 15 cm. (6 in.) in the adult, and the distance from the teeth to the cardiac orifice of the stomach is 48 to 50 cm. (16 or 17 in.).
and 715.
Tonsils. — The relations of the tonsils should be carefully examined. Thus, they are separated externally by the superior constrictor and pharyngeal aponeurosis from the oscending pharyngeal and internal carotid arteries. The latter vessel lies about 2.5 cm. (1 in.) behind and to the lateral side of the tonsil. When serious haemorrhage follows operations here, it usually comes from one of the numerous tonsillar branches (fig. 448). The extent to which the tonsil is covered by the anterior pillar, how far it projects upward beneath the soft palate or downward into the pharynx, have all important bearings on the mode of removal. Its position corresponds to a point a little above and in front of the angle of the jaw. The lateral surface, enclosed by an imperfect capsule and separated from the superior constrictor by connective tissue, explains how an enlarged tonsil can be dragged medialwarcl by a vulsellum, and enucleated after an incision in the mucous membrane around. It is in this connective tissue that severe infective inflammation, e. g., after scarlet fever or an imbedded pipe-stem, may set up haemorrhage or spreading cellulitis, retro-pharyngeal or otherwise.
The finger introduced downward at the back of the mouth, especially if the parts are rendered in sensitive by local anaesthetics, feels the vallate papilla, the lingual and laryngeal surfaces of the epiglottis, the arytajno-epiglottidean folds, with the cuneiform and corniculate cartilages. If the finger be moved upward behind the soft palate and turned upward to the base of the skull, and then forward, it will feel the choanae (posterior nares), separated by the vomer. Tlie other boundaries of these are, laterally, the medial pterygoid plate and palate bones; above, the basisphenoid; and below, the horizontal plate of the palate bone and the inferior nasal spine. Within each nostril would be felt the posterior ends of the two lower nasal conchte (turbinate bones); above and behind is felt the basilar process of the skull, the vault of the pharynx, and the bodies of the upper cervical vertebree (fig. 1097).
The size of the choanae, in the bony skull 2.5 cm. (Ijin.) vertically by 1.2 cm. (J in.), and the presence of anj^ adenoids, are especially to be noted. The richness of the naso-pharynx in glandular structures, its proneness to inflammation, and of this inflammation to spread to other parts, — e. g., the tympanum, — ^are well known. The finger should be familiar with the feel of
adenoids — i. e., hypertrophied post-nasal lymphatic nodules — soft bodies of irregular shape blocking up the naso-pharynx. _ To make out how far this is the case, it is well to take the nasal septum as the starting-point.
Pharyngeal hypophyseal remnants. — In the naso-pharyngeal mucosa, a few millimetres behind the posterior border of the vomer, a group of glandular cells may be found on microscopical examination in all cases (Haberfeld), corresponding in histological appearance with the pars anterior of the hypophysis. These cells are a remnant of the primitive bud that grows toward the brain in front of the bucco-pharyngeal membrane to form the pars anterior of the hypophysis. In some cases of pituitary disorder they give rise to a palpable tumour in the nasopharynx.
The palate.- — Between the diverging pillars of the soft palate is the isthmus faucium, bounded above by the free margin of the palate, and below by the dorsum of the tongue. The space between the arches (pihars), glossopalatine and pharyngo-palatine, with attachments denoted by their names, shallow above, widens and deepens below. Of its lateral boundaries, the posterior pillars come nearer each other than the anterior. The coverings of the hard palate are chiefly mucous membrane, glands, and periosteum. These are intimately blended by fibrous septa, as in the superficial layers of scalp and palm of the hand. Hence the readiness with which necrosis takes place here.
The palate is developed from three primitive processes growing down from the basis cranii, viz., (1) the mesial nasal process forming the premaxilla which lies in front of the anterior palatine foramen and bears the four incisor teeth, (2) and (3) the maxillary process of either side. The slighter cases of failure to unite affect only the soft palate which is the last part to fuse. Complete alveolar cleft palate, which occurs combined with hare-lip and may be unilateral or bilateral, represents more serious non-union. In this condition the lateral incisor may be found either on the medial or on the lateral side of the cleft, which is explained by the fact that thi& tooth is developed in the groove between the two processes (Keith).
In paring the edges of a cleft soft palate, the following structures would be, successively, cut through: — (1) Oral mucous membrane; (2) submucous tissue, with vessels, nerves, and glands; (3) glosso-palatine muscle; (4) aponeurosis of tensor palati; (5) anterior fasciculus of pharyngo-palatine; (6) levator palati and uvular muscles; (7) posterior fasciculus of pharyngopalatine; (8) submucous tissue, vessels, nerves, and glands; (9) posterior mucous membrane. The soft palate is thicker than it seems, the average in an adult being 6 mm. (i in.). The muscles widening a cleft are the tensor and levator, while the superior constrictor closes it in swallowing. Of the arteries of the palate, from the external maxillary (facial), ascending pharyngeal, and internal maxillary, the largest is the descending palatine branch of the last. This emerges from the posterior palatine canal close to the inner side of the last molar tooth.
On the face the outline of the nasal bones can be easily traced, and below them the lateral nasal cartilages, flat and also somewhat triangular. Below these are the greater alar cartilages, curved and so folded back that each forms a lateral and a medial plate. Of these, the medial meet below the septal cartilage to form the tip of the nose, while the lateral curve backward, and, together with dense masses of cellular tissue and fat and accessory cartilages, form the alse.
With the speculum, especially if the head be thrown back and the tip of the nose drawn up, the lower part of the septum, floor of the nose, and greater portion of the inferior concha (turbinate bone) can be seen. On throwing the head further back, with a good light the lower margin of the middle concha can also be made out. This is much higher up and nearly on a level with the root of the nasal bone. The septum often deviates to one side. The mucous membrane over it is, in health, dull red in colour; that over the inferior concha is thicker. The anterior extremity of the latter bone is about 1.8 cm. (| in.) behind the nasal orifice, while the opening of the naso-lacrimal duct is about 2.5 cm. (1 in.) behind and about 1.8 cm. (| in.) above the floor, concealed by the anterior extremity of the inferior concha. The opening into the maxillary sinus (antrum) is situated in about the centre of the middle meatus and 2.5 cm. (1 in.) above the floor
The olfactory area of the mucous membrane extends over the highest concha (possibly also somewhat lower) and corresponding portions of the septum. The respiratory portion is more vascular and thicker, especially over the conchse. It is firmly adherent to the periosteum and perichondrium. The veins, especially over the lower conchse, form a dense plexus, closely resembling cavernous tissue.
About 1.2 cm. (| in.) behind tlie posterior extremities of tiie inferior conchse, just above the level of the hard palate (fig. 1097), on the side of the naso-pharynx, are the openmgs of the tubce auditivce (Eustachian tubes). Oval in shape, these are bounded above and behind by the prominence of the cartilage, which is wanting below, thus facilitating the entry of a catheter. The lower part of the tube contains in early life lymphoid tissue; enlargement of this explains the deafness in certain cases of adenoids. At the upper part of the naso-pharynx, on the posterior wall, extending down laterally as far as the tubae auditivse, is the collection of lymphoid tissue known as the pharyngeal tonsil, which when hypertrophied, plays a large part in 'naso-pharyngeal adenoids.' From the periosteum of the basi-sphenoid and basi-occipital arise naso-pharyngeal fibromata.
Nasal septum. — The structure of the skeletal element of the septum, which consists of the septal cartilage, the vertical plate of the ethmoid and the vomer, is shown in fig. 1099. Slight deviations of the septum to one side are common in adults, and involve mainly the cartilage and the ethmoid bone, the vomer being but little affected as a rule.
The convexity is most commonly on the right side, and occlusion of the nares on that side with unsightly deflection of the whole nose, results in some cases during the transition from the nfantile to the adult facial conformation. Too extensive removal of the bony septum in the operation of submucous resection for the relief of this condition may cause sinking in of the bridge of the nose. More often, however, this is due to the destructive effect of congenital syphilis.
Accessory sinuses. — The communication of these air sinuses with the nasal fossae are of great clinical importance. The sphenoidal sinus opens high up into the spheno-ethmoidal recess. The posterior ethmoidal sinuses open into the superior meatus under cover of the superior concha. The infundibulum of the frontal sinus, the anterior and middle ethmoidal and the maxillary sinus all communicate with the middle meatus under cover of the middle concha. The orifice of the maxillary sinus lies at the lowest part of the hiatus semilunaris into the front and upper end of which the frontal sinus opens. Consequently infected fluid may trickle down from the latter into the maxillary sinus. The orifice of this sinus is placed high up in its medial wall so that fluid does not drain away from it readily in case of infection. When the head is held forward in a stooping position some of the pus or mucus may escape from the nostrils, since in this position the fluid contents more readily reach the orifice.
mastoid, clavicle, triangles and cervical ribs.
Bony and cartilaginous landmarks. — The body of the hyoid is nearly on a level with the angles of the jaw, and the interval between the third and fourth cervical vertebrae (fig. 1097). It divides the front of the neck into supra- and infra-hyoid regions, convenient for remembering the distribution of the deep fascia. On either side of the body are the great cornua, with the lesser cornua attached to their upper borders at the junction with the body. The upper borders of these are the guides to the lingual arteries. The outline and mobility of the body and the great cornua are easily determined by relaxing the deep fascia and pushing the bone over to the opposite side. Below the hyoid is the thyreo-hyoid space, which corresponds with the epiglottis and the upper aperture of the larynx. Thus, if the throat be cut above the hyoid, the mouth will be opened and the tongue cut into; if the thyreo-hyoid space be cut, the pharynx would be opened and the epiglottis wounded near its base. In the former case the lingual and external maxillary are the most likely vessels to be wounded ; in thyreo-hyoid, the commonest cut-throat, the superior thyreoid vessels, and the superior laryngeal nerve. The projection of the thyreoid notch, about 2.5 cm. (1 in.) below the hyoid, is much more distinct in men than in women or children. It does not appear before puberty, and thus flatness of the thyreoid must be expected
necks.
The cricoid, on the other hand, is always to be made out. It corresponds in horizontal plane to the following: — (1) The sixth cervical vertebra. (2) The junction of pharynx and oesophagus: from the narrowing of the tube here, foreign bodies may lodge at this point and cause dyspncea by pressing on the air-tube in front. The cricoid is taken as the centre of the incision in cesophagotomy, and also for ligature of the common carotid. (3) The junction of larynx and trachea. (4) The crossing of the omo-hyoid over the common carotid. (5) The middle cervical ganglion. Above the cricoid is the crico-thyreoid rnembrane. In laryngotomy, the deepest part of the incision should be kept to the middle line for fear of injuring the cricothyreoids, and as near the cricoid as possible, so as to avoid the neighbourhood of the vocal cords and the small crico-thyreoid vessels. The space is always small, and, after middle life, increasingly rigid.
The distance between the cricoid and the manubrium is only about 3.7 cm. (1| in.). When the neck is stretched, about 1.8 cm. (f in.) more is gained. Thus, as a rule, there are not more than seven or eight tracheal rings above the sternum. Of these, the second, third, and fourth are covered by the thyreoid isthmus.
The parts met with in the middle line — (a) above, and (6) below, the isthmus — high and low tracheotomy — should be borne in mind: (o) Skin, superficial fascia, branches of transverse cervical and infra-mandibular nerves, lymphatics, cutaneous arteries, anterior jugular veins — with their transverse branches smaller above — deep fascia, sterno-hyoids, cellular tissue, superior thyreoid vessels, and pre-tracheal layer of deep fascia. The importance of this last is twofold, as, first, the tube in tracheotomy may be passed between it and the trachea, and after a wound in this region this layer, continuous with the pericardium, may conduct discharges into the mediastina, (6) The surface structures are much the same, but the anterior jugular veins and their transverse branches are much larger. The inferior thyreoid veins are also larger. A thyreoidea ima may be present, and the innominate artery, especially in children, may be 1.2 cm. (2 in.) above the sternum. The trachea is also smaller, deeper, and less steadied by muscles. The thymus, too, in young children, may prove a difficulty. Thus, in children, the high operation, incising the cricoid and crico-tracheal membrane, if needful, is to be preferred. The cricoid is, however, not to be incised, if possible; the higher the tube is inserted, the greater the irritation.
The suprasternal notch, between the sternal heads of the sterno-mastoids in on a level with the disc between the second and third thoracic vertebrae. Just below the level of the cricoid cartilage, on deep pressure at the anterior border of the sterno-mastoid the transverse process of the sixth cervical vertebra may be felt. It is known as Chassaignac's carotid tubercle, and the common carotid may be compressed against it. Compression below it will command the vertebral artery as well.
The thyreoid gland enclosed in a capsule of deep fascia derived from the pretracheal layer (fig. 1070) is closely connected by this to the upper trachea and larynx. The upper somewhat pointed extremity of each lateral lobe reaches to the upper and back part of the thyreoid cartilage; here enter the superior thyreoid vessels. The lower layer and rounded extremity reaches to the fifth or sixth tracheal ring; its posterior and lower aspect is in relation to the inferior thyreoid vessels and the recurrent nerve; the lateral lobe, posteriorly, also overlaps the carotid sheath, which may be infiltrated in malignant disease of the thyreoid. The thyreoidea ima has been mentioned above.
The isthmus in the adult is opposite to the second, third, and fourth tracheal rings. At its upper border is an arterial arch formed by the superior thyreoids; over the anterior surface of the gland and isthmus the inferior thyreoid veins take origin in a plexus. The upper border of the thymus (fig. 1100) may be in relation with the lower border of the isthmus. From the upper border of the latter, the pyramidal lobe, especially on the left side, is often present, reaching by a pedicle to the liyoid. The pyramidal lobe, when present, is the persistent remnant of the thyreo-glossal duct, and occasionally cystic outgrowths persist obstinately as remnants of this duct, in the middle line, above, behind, and below (the commonest form) the hyoid bone. In short-necked people the thyreoid is relatively lower in relation to the sternum, and enlargements of the gland are apt to become mainly intra-thoraeic. An enlargement of the thyreoid is liable to give trouble by pressure on (1) the trachea, which is compressed laterally between the lateral lobes; (2) the oesophagus; (3) the internal jugular vein and carotid artery; (4) the reciu-rent laryngeal or cervical sympathetic nerves.
Parathyreoids. — These small glands, about the size of a pea, vary somewhat in number and situation. There are usually four — t^A■o behind each lateral lobe. The upper glands lie imbedded in the capsule of the thyreoid about the junction of the middle and upper thirds of the lateral lobes on the posterior aspect. The lower pair lie nearer the lower poles of the lateral lobes, sometimes separated from them by a distinct interval. Excision of all the parathyreoids gives rise to tetany in animals.
the common carotid corresponding, as far as the upper border of the thyreoid, with a line drawn from the sterno-clavicular joint to midway between the mastoid process and the angle of the jaw. The artery can be best compressed above the level of the cricoid, as here it is less deeply covered. The student should recall the deep relations of the sterno-mastoid, which he may classify as vessels, nerves, muscles, glands, and bones; or, according to their position, (1) those above the level of the angle of the jaw; (2) those between the angle of the jaw and the omohyoid; (3) those below the omo-hyoid.
Of the two heads of the sterno-roastoid, the sternal is the thicker and more prominent, the clavicular the wider. A stab through the interval wliich lies between tlie two heads might wound the bifurcation of the innominate on the right side, and the common carotid on the left, the internal jugular, vagus, and phrenic veins, according to the direction of the wound.
The anterior jugular, commencing in branches from the submaxillary and submental regions, descends at first in the superficial fascia between the middle line and anterior border of sterno-mastoid, perforates the deep fascia just above the clavicle, here entering Burns's space (p. 1361); it then curves laterally to pass beneath both origins of the sterno-mastoid a little above the clavicle, to end usually in the external jugular.
When distended, a large communicating branch between it and the common facial, which runs along the anterior border of the sterno-mastoid, must always be remembered in operations for removal of glands, etc. The varying level at which the external jugular crosses the lateral
border of the clavicular origin must be remembered in such operations as tenotomy here. These veins vary in size inversely to each other; the anterior jugulars are joined by numerous transvesre branches and become larger below. They have no valves.
Behind the stemo -clavicular joint lies the commencement of the innominate veins, the bifurcation of the innominate artery on the right, and the common carotid artery on the left; deeper still lie the pleura and lung.
The clavicle. — This bone can be felt beneath the skin in its whole length. It forms the only bony connection between the upper limbs and the trunk. As one traces it laterally toward the acromial end, it rises somewhat, particularly in children and in subjects of good muscular development. The skin over it is thin but very mobile, and consequently is not often wounded. The most important posterior relations of this bone are, passing from the medial end laterally, the subclavian vein, the subclavian artery, and the cords of the brachial plexus as they He on the first rib.
The vein occupies the angle between the first rib and the clavicle, and hence is, as a rule, the first structure compressed in growths of this bone. The artery lies on a deeper plane behind the mid-point of the clavicle, and the nerve cords extend a little further laterally. The Bubclavius muscle forms a protective cushion between the bone and these important structures, and this accounts for the rarity of injury to them in fracture of the clavicle. Behind the medial half of the clavicle the apex of the lung extends upward into the neck toa height of 2. 5-3. 7 cm. (1-1 2 in.), and consequently is liable to be wounded by a stab in the root of the neck.
Cervical triangles. — In front of the sterno-mastoid is the anterior triangle, which is subdivided into three smaller triangles by the digastric muscle above, and the anterior belly of the omo-hyoid below (fig. 1101). These smaller triangles are called, from above, the submaxillary, the superior and inferior carotid triangles.
The submaxillary or digastric triangle is bounded above by the jaw, and a line drawn back to the mastoid process; below, by the digastric and stylo-hyoid muscles; and in front by the middle line of the neck.
This space contains the submaxillary gland, and embedded in the gland is the external maxillary artery, the facial vein lying superficial to the gland; deeper than the gland are the submental vessels and the mylo-hyoid vessels and nerve. Posteriorly, and separated from the above structures by the styro-mandibular ligament, which subdivides the triangle into a submaxillary and parotid part, is the upper part of the external carotid artery running up into the parotid gland, where it gives off its two terminal and the posterior auricular branches. More deeply lie the internal jugular vein, internal carotid artery, and the vagus. The floor of the triangle is formed by the mylo-hyoid, hyo-glossus, and superior constrictor. The lingual artery may be tied here, or, better, in order to get behind the dorsalis linguae, close to its origin, by an incision similar to that for exposing the external carotid.
The superior carotid triangle is bounded above by the digastric, below by the omo-hyoid, and behind by the sterno-mastoid. It contains the upper part of the common carotid and its branches, the external being at first somewhat anterior to the internal. All the branches of the external carotid, save the three just given, are found in this space, together with their veins, the internal jugular vein, the vagus and sympathetic nerves, and, for a short distance, the accessory, together with those nerves which lie in front of and behind the carotids.
Ligature of the common carotid is usually performed at the 'seat of election,' where the vessel is more superficial, above the omo-hyoid. An incision with its centre opposite the cricoid is made 7.5 cm. (3 in.) long in the line of the carotid artery. The deep fascia along the anterior border of the sterno-mastoid having been divided, the cellular tissue beneath is opened up, the omo-hyoid identified and drawn down or divided. The sterno-mastoid is next drawn well laterally, and the artery felt for. At this stage, such veins as the communication between the common facial and the anterior jugular and the superior and middle th}Teoi_ds may give trouble. The sheath is next opened well to the medial side, opposite to the cricoid cartilage, the ascending cervical, when seen, being avoided. If the internal jugular be distended, it may be drawn aside with a blunt hook, or pressure made lightly in the upper angle of the wound. The needle should be passed from the lateral side in very close proximity to the lateral and back part of the artery, so as to avoid the vein and vagus. Ligature helow the omo-hyoid is rendered more difficult by the presence of the anterior jugular, the pretracheal muscles, an overlapping thyreoid gland, especially if enlarged, the greater depth of the artery, especially pn the left side and, here also, the closeness of the internal jugular. The collateral circulation is given at p. 1360. Ligature of the external carotid, otherwise difficult, is rendered very simple by first exposing the bifurcation of the common carotid artery, the incision similar to the last being prolonged upward. Here the facial and lingual veins and hypoglossal nerve cross the trunk, over which also lie some of the deep cervical glands. The ligatiue is usually placed between the superior thyreoid and lingual branches.
Allusion must here be made to the chief structures liable to be met with in operations on the neck. These are the internal jugular, the accessory, and phrenic nerves, the vagus and hypoglossal, the thoracic duct, low down and deep on the left side, the oesophagus and recurrent nerve in difficult operations on the thyreoid gland. Of these, the internal jugular is, in some ways, the most important. Glands, tuberculous or epitheliomatous, are often adherent to its sheath, especially those which drain the submaxillary group. When this condition is present or suspected, it is always well to begin the dissection low down in the inferior carotid triangle, where the structures are probably normal and the landmarks easy to identify. In infective thrombosis of the transverse sinus the internal jugular is often tied opposite to the cricoid cartilage, being either divided between two ligatures, or, if the thrombus has extended downward, as much of the vein as is possible is removed. This vein contains only a single pair of valves low down in the neck. In all operations here on it and the other two jugulars, the risk of entry of air is to be remembered. The accessory and phrenic nerves are alluded to on p. 1360.
The inferior carotid or tracheal triangle is bounded above by the omo-hyoid, behind by the sterno-mastoid, and in front by the middle line of the neck. It contains the lower part of the carotid sheath and its contents, with, behind^ it, the inferior laryngeal nerve and inferior thyreoid vessels, and to the medial side the trachea, thyreoid gland, and oesophagus. More deeply are the vertebral vessels; on the left side is the thoracic duct.
origin of most of them.
The superior thyreoid, arising just below the level of the great cornu of the hyoid bone, passes downward and forward to the back part of the thyreoid cartilage and upper part of the thyreoid body. Many of its branches are important in surgery. The superior laryngeal perforates the thyreo-hyoid membrane. The sterno-mastoid passes laterally into the middle of the muscle, across the carotid sheath. The crico-thyreoid crosses the space of the same name just below the lower border of the thyreoid cartilage. The small hyoid branch runs to the lower
THE NECK 1359
border of the hyoid bone. Anastomosing branches of the superior thyreoid form an arch along the upper border of the isthmus. The Ungual artery arises from the parent trunk, opposite the tip of the great cornu of the hyoid, and passes forward just above the great cornu, crossed by the hypoglossal, and thence to the side of the tongue. In the first part of its course, before it reaches the hyo-glossus, it is curved, at first ascending, and then, having descended slightly, before it reaches the hyo-glossus, and while it lies under it, its curve is gentle, with the concavity upward; beyond the hyo-glossus, as it lies on the muscles of the tongue beneath the mucous membrane, it is tortuous. The lingual vein, it will be remembered, does not run with its artery, but lies superficial to the hyo-glossus. It receives the two small venae comitantes which run with the lingual itself just before it crosses the common carotid. The line of the external maxillary (facial) artery (fig. 1093), which often arises with the lingual, has been given on p. 1343. The occipital artery, starting on the same level as the facial (i. e., at a point a little above and outside the tip of the great cornu of the hyoid bone), follows a line drawn upward and laterally, first to the interval between the transverse process of the atlas and the mastoid process, the former bone being felt just below and in front of the tip of the latter; thence, lying in the occipital groove of the mastoid, the artery ascends gradually, enters the scalp, together with the great occipital nerve, a little medial to a point midway between the external occipital protuberance and the mastoid process, to follow, tortuously and superficial to the aponeurosis, the line of the lambdoid suture.
The surface marking of the digastric and omo-hyoid, which subdivide the anterior triangle into the three smaller subtriangles above described, should be noted. The line of the posterior belly of the digastric corresponds to one drawn from the apex of the mastoid process to a point just above the junction of the great cornu and body of the hyoid bone; and from this spot, which gives the point of meeting of the two tendons, one slightly curving upward to a point just behind the symphysis menti, would give that of the anterior belly.
To trace the omo-hyoid, a line should be drawn from the lower margin of the side of the hyoid bone obliquely downward, so as to cross the common carotid opposite the cricoid cartilage and thence curving laterally under the sterno-mastoid at the junction of its middle and lower thirds, and then onward and still laterally parallel with and a little above the clavicle, as far as its centre.
Posterior triangle. — This shows in its lower part a wide<depression, the supraclavicular fossa. Here the brachial plexus may be felt, and, by pressure downward and backward immediately behind the clavicle, just lateral to and behind the lateral margin of the sterno-mastoid, the pulsation of the subclavian artery can be stopped against the first rib.
The supra-clavicular fossa should be opened out by depressing the arm, and parts relaxed by carrying the shoulder forward and turning the head to the same side. This vessel curves upward and laterally from behind the sterno-clavioular joint to disappear behind the centre of the clavicle, the highe.st point of the curve being 1.2 to 2.5 cm. (i to 1 in.) above the bone. The artery on the left side lies more deeply than the right, and does not rise so high into the neck. The subclavian vein lies at a lower level, separated by the scalenus anterior, and under cover of the clavicle. Into the above curve rise the pleura and lung. The pleura must be expected to rise 2.5 cm. (1 in.) above the clavicle, behind the clavicular head of the sterno-mastoid.
The transverse scapular and transverse cervical vessels run laterally, parallel with the clavicle. The former lies behind the bone and subclavius ; the latter also runs laterally in a transverse direction, across the root of the neck, but on a slightly higher plane, and thus a little above the clavicle.
Ligature of the third part of the subclavian is best performed by an angular incision, the horizontal portion along the centre of the clavicle, and the vertical one along the posterior border of the sterno-mastoid, with partial division of this and the trapezius when closely adjacent. The chief points to bear in mind are the venous plexus into which the external jugular, transverse cervical, transverse scapular, and cephalic veins enter; the omo-hyoid and division of the fascia which ties this to the clavicle; identification of the lateral margin of the scalenus anterior and the scalene tubercle; care of the transverse scapular artery and the descending branch of the transverse cervical. The needle is passed from above downward so as not to include the lowest cord of the brachial plexus, the vein, if distended, being depressed with a blunt hook. If the nerve to the subclavius be seen, it must be uninjured, as it occasionally forms an important part of the phrenic. The collateral circulation is given at p. 1360.
Crossing the sterno-mastoid, a little obliquely, in a line drawn from a point just below and behind the angle of the jaw which marks its origin in the union of the posterior part of the internal maxillary and the posterior auricular veins to the centre of the clavicle, runs the external jugular vein. Above, it lies between the platysma and deep fascia, and is accompanied by the group of superficial cervical nodes (p. 709). About 3.7 cm. (1| in.) above the clavicle it perforates the deep cervical fascia, its coats being blended with the opening. Gentle pressure with a finger at this point renders the vein above clearly visible. The dilated part between this point and the subclavian vein is called the sinus, and is marked by two valves, neither of which is usually perfect.
Opening into the external jugular, in the middle or lower third of its course, is the posterior external jugular, a vessel which begins in the occipital region superficially and runs down in front of the anterior border of the trapezius, across the posterior triangle.
The accessory nerve, having crossed the transverse process of the atlas at a point lying a little below and in front of the apex of the mastoid, enters the anterior border of the sterno-mastoid at about the junction of the upper and middle thirds of the muscle. Having traversed the muscle obliquely, it leaves it usually at a point a little lower down, pursues a similar course across the posterior triangle and disappears under the anterior border of the trapezius, to enter into the subtrapezial plexus with the third and fourth cervical nerves.
Above it is accompanied by a branch from the occipital, below by the transverse cervical artery. It is always seen in thorough operations on the upper deep cervical glands. The nerve is resected in spasmodic torticollis, and in recent years inveterate facial paralysis has been treated by anastomosing the facial to this nerve or the hypoglossal. A line drawn from midway between the tip of the mastoid and the angle of the mandible along the above given course of the nerve would denote its position.
Just above the centre of the sterno-mastoid, the small occipital, great auricular, and cutaneous cervical nerves emerge, the first passing upward and backward to the scalp, the second upward and forward across the upper part of the sterno-mastoid to the ear, and the last turning straight forward to the front of the neck. The small occipital and great auricular are often in intimate association with the accessory at its exit from the muscle. At this point also care must be taken not to injure the nerve in removal of glands from the posterior triangle.
The phrenic nerve, taking its largest root from the fourth cervical, would begin deeply about the level of the hyoid bone; thence descending under the sterno-mastoid, and, passing obliquely medially across the scalenus anterior (the posterior borders of the above two muscles roughly correspond to each other in the lower part of the neck), it descends under the subclavian vein and clavicle to enter the thorax.
When the internal j ugular is distended, its lateral border will be liable to overlap this nerve. The relations of the scalenus anterior should be noted here. In addition to the plurenic, which runs with a slight obliquity medially and is in close contact with the muscle, the following structures cross it medio-laterally : the subclavian vein and termination of the external jugular, the transverse scapular and transverse cervical vessels, and the omo-hyoid. At its medial margin are the thyreo-cervical trunk and vertebral arteries, and over them, the internal jugular. Behind it are the subclavian artery, the brachial plexus, and pleura.
The level of the brachial plexus (upper border) would be given by a line drawn from the cricoid cartilage to the centre of the clavicle. The lowest, medial cord (eighth cervical and first thoracic, giving off chiefly the ulnar, medial head of median, and medial antibrachial cutaneous) is just above and behind the subclavian artery. Its importance in ligature of the artery has been referred to (p. 1359).
In paralys's of the newly born, after some violent manipulation, it is usually the upper and lateral cord (fifth nerve, and axillary and median chiefly) which suffers, elevation and abduction at the shoulder and flexion at the elbow-joint being lost.
Collateral circulation after ligature of the common carotid (fig. 1102). — This takes place by means of (1) the free communication which exists between the opposite carotids, both without and within the craniujm; and (2) by enlargement of the branches of the subclavian artery on the same side as that on which the carotid has been tied. Thus, outside the cranium, the superior and inferior thyreoids are the chief vessels employed (fig. 1102). Within the cranium the vertebral replaces the internal carotid.
(a) Arrangement above the hyoid bone. — Here two chief processes can be made out: — (i) one, continuous with that in front of the sterno-mastoid, traced upward from the hyoid bone, -encloses the submaxillary gland, passing over the mylo-hyoid, and, ascending, is connected with the lower border of the mandible, gives off the masseteric and parotid fascia, and is attached to the lower border of the zygoma, and, more posteriorly, to the mastoid and linea nuchse Buprema. (ii) A special process, which forms the stylo-mandibular ligament, is important in its power of checking over-action of the external pterygoid. By both these processes the anterior border of the sterno-mastoid is tied firmly forward to the mandible about its angle, and more deeply to the styloid process. This renders all operations under the upper part of the muscle, •e. g., the removal of glands, extremely difficult.
(6) Below the hyoid bone. — The importance of the fascia here is infinitely greater. Four layers must be rememhored; (i) Superficial; (ii) pretracheal; (iii) prevertebral; (iv) carotid, (i) Superficial. This starts from the ligamentum nuchee, encases the trapezius, forms the roof of the posterior triangle where it is perforated by branches of the superficial cervical nerves and the external jugular
triangle, it meets its fellow in the middle line.
jThin behind, it is thickened anteriorly. Behind this thickened union lie the anterior jugular veins. Below, at a varying distance below the thyreoid cartilage, this layer divides into two, attached to the front and back of the manubrium. Between these (Burns*s space)
lie some fat, a small gland, a communicating branch between the anterior jugulars and a small portion of the veins, and the sternal heads of the sterno-mastoids. The sheath to the depressors of the hyoid bone is partly derived from this layer, partly from the next. Laterally, this layer gives a sheath to the posterior belly of the omo-hyoid, is attached to the clavicle, and passing on, is continuous with the sheath to the subclavius and coraoo-clavioular fascia.
(ii) Pretracheal or middle. This lies under the depressors of the hyoid, over the trachea, also encasing the thyreoid gland. Farther laterally it helps, together with the prevertebral, to form the carotid sheath. Traced downward, the pretracheal layer passes over the trachea into the thorax (middle mediastinum)
As it descends, it encases the left innominate vein, and ends by blending with the fibrous layer of the pericardium. Hilton suggested that the attachment of this fascia above, and that of the central tendon of the diaphragm below, to the pericardium served to keep this sac duly stretched, and so prevented any pressure of the lungs upon the heart.
(iii) Prevertebral. This layer passes over the longus colli and capitis upward to the base of the skull, and downward over the longus colli behind the oesophagus into the posterior mediastinum. Laterally it helps to form the carotid sheath, and, lower down, gives a sheath to the subclavian artery and so to the axillary, (iv) The carotid sheath. This is formed by septa from i, ii, and iii, meeting under the sterno-mastoid (fig. 1103).
The following uses and important points with regard to the anatomy of the deep cervical fascia should be noted: — (A) It forms certain definitely enclosed spaces in which pus or growths may form, and by the walls of which these morbid structures may be tied down and thus rendered difficult of diagnosis, while their increasing pressure may embarrass the air-passages, etc. Thus: (1) In the first space, which lies between No. 1 and the skin, the structures met with, the platysma and superficial branches of the cervical plexus, are unimportant. Any abscess here is prone to extend, but superficially. (2) In the second space, between the superficial and middle layers, lies a narrow space containing loose cellular tissue and lymphatic glands. Suppuration here is very common, but usually comes forward. (3) This is the largest and most important of all. From its contents it has been called the visceral compartment. (Stiles.)
It is bounded in front by the middle, and behind by the prevertebral layer. Its contents are — larynx, trachea, cesophagus, thyreoid, carotid sheath, glands; and below, brachial plexus, subclavian artery, and abundant loose cellular tissue for the movements of the neck. Suppuration is somewhat rarer here; but either pus or growths, if oonfined in this space, may have baneful effects, from pressure, or from their tendency to travel behind the sternum. (4) This space between the prevertebral layer in front and muscles behind, is very limited. Retropharyngeal abscess forms here, and the dyspnoea it causes is thus explained. The origin of such abscesses is chiefly twofold, either in one of the highest deep cervical nodes, e. g., from infection of the naso-pharynx (p. 717), or from disease of the upper cervical vertebrae. In the former cases CStiles, Chiene) the suppuration will be in front of the prevertebral fascia, pointing toward the pharynx; in the latter behind the above fascia, spreading laterally, behind the carotid sheath. In making his incision, now along the posterior border of the sterno-mastoid, the surgeon should keep close to the transverse processes of the vertebrae, to avoid!opening the visceral compartment and infecting the structures in it. (B) The deep cervical fascia gives sheaths or canals tc> certain veins which perforate it, e. g., the external jugular. These are thus kept patent, and a. ready passage of blood ensured from the head and neck. Further, this fact accounts for the readiness with which air may enter veins, in operations low down in the neck. The carotid sheath is another and different instance. (C) It helps to resist atmospheric pressure. (D) Hilton's suggestion as to its action on the pericardium has already been mentioned.
Bony landmarks. — The top of the sternum corresponds (in inspiration) to the fibro-cartilage between the second and third thoracic vertebrae, and is distant about 6.2 cm. (2| in.) from the spine. In the newborn child it corresponds to the middle of the first thoracic vertebra (Symington). If traced downward, the subcutaneous sternum presents a ridge (sternal angle of Louis) opposite to the junction of the manubrium and body, and the second costal cartilages on either side; this ridge usually corresponds to the disc between the fourth and fifth thoracic vertebrae. At the lower extremity of the sternum the xiphoid cartilage usually retires from the surface, presenting the depression of the epigastric angle or 'pit of the stomach.' This is opposite to the seventh costal cartilages and the expanded upper end of the recti, and corresponds to the tenth thoracic vertebra behind.
The left innominate vein crosses behind the sternum just below its upper border. Next come the great primary branches of the aortic arch. Deeper still is the trachea, dividing into its two bronchi opposite to the junction of the first and second bones of the sternum. Deepest of all is the cesophagus. About 2.5 cm. (1 in.) below the upper border of the sternum is the highest part of the aortic arch, lying on the bifurcation of the trachea. (Holden.) (Fig. 1104).
Sterno-clavicular joint. — The expanded end of the clavicle and the lack of proportion between this and the sternal facet, on which largely depends the mobility of this, the only joint that ties the upper extremity closely to the trunk, can be easily made out through the skin. Its strength, considerable when the rarity of dislocation compared with fracture of the clavicle is considered, depends mainly on its ligaments, the buffer-bond meniscus, the costo-clavicular ligament, which checks excessive upward and backward movements, and the fact that the elastic support of the first rib comes into play in strong depression of the shoulder as in carrying a weight. The relative weakness of the anterior ligament determines the greater frequency of anterior dislocation of the clavicle at this joint.
Acromio -clavicular joint. — On tracing the clavicle laterally, it is found to rise somewhat to its articulation with the acromion. This joint has very little mobility, and owes its protection to the strong conoid and trapezoid ligaments hard by. Owing to the way in which the joint-surfaces are bevelled, that of the clavicle looking obliquely downward, and resting upon the acromion, it is an upward displacement of the clavicle which usually takes place.
verse line at the junction of the manubrium and body of the sternum. It is well always to count ribs from this point and never from below, as the twelfth rib varies in size and may be obscured by the sacro-spinalis muscles. The nipple in the male, lies between the fourth and fifth, nearly an inch lateral to their cartilages. The lower border of the great pectoral corresponds to the fifth rib. The seventh, the longest of the ribs, is the last to articulate by its cartilage with the sternum. When the arm is raised, the first three digitations seen of the serratus anterior correspond to the fifth, sixth, and seventh ribs. The ninth rib
is the most oblique. The eleventh and twelfth can be felt lateral to the sacrospinalis. Owing to the obliquity of the ribs, their sternal ends are on a much lower level than their vertebral extremities.
'Thus the first rib in front corresponds to the fourth rib behind, the second to the si.xth, the thu-d to the seventh, the fourth to the eighth, the fifth to the ninth, the sixth to the tenth, and the seventh to the eleventh. If a horizontal line be drawn round the body from before backward at the level of the inferior angle of the scapula, while the arms are at the sides, the line would cut the sternum in front between the fourth and fifth ribs, the fifth rib at the nipple line, and the ninth rib at the vertebral column.' (Treves.) The most frequently broken are the sixth, seventh, and eighth. The upper four and the two lowest ribs are best covered by soft parts, and, in the case of the former, the shoulder and arm take off some of the violence that would otherwise reach them. The way in which the ribs are embedded in the soft parts (fig. 1106), and the fact that the fragments are often held in place by the periosteum, account for the difficulty which is often met with in detecting crepitus. The intercostal spaces are wider in front than behind. The three upper are the widest of all.
Cervical ribs. — It occasionallj' happens that the rib element of the seventh cervical vertebra, normally fused with the true transverse process, is segmented off as a separate, though usually rudimentary, rib. This anomaly is generally bilateral. It occurred in 3 of 260 subjects (1.16 per cent.) examined by Wingate Todd.*
The anterior extremity of a cervical rib may, according to the degree of its development (1) lie free amongst the scalene muscles; (2) be connected with the sternum by a hgameutous prolongation; (3) articulate with the upper surface of the first thoracic at about its centre by a synchondrosis, or (4) form a complete rib, articulating by a costal cartilage with the sternum.
The lowest trunk of the brachial plexus formed by the eighth cervical and first thoracic roots, the subclavian artery and less commonly the subclavian vein, curve over the upper surface of these ribs. The abnormality owes its clinical importance to the pressure effects produced on the nerve trunk in a small proportion of the cases. This pressure is manifested by ( 1) pain, going on to anaesthesia down the medial side of arm, forearm and hand; (2) paralysis of the intrinsic muscles of the hand, producing the main en griffe, and to a less extent of the muscles of the forearm; (3) vascular effects (anamia, gangrene, etc.), manifested chiefly in the hand. Todd has shown that these vascular effects are not due to mechanical pressure on the subclavian artery by the cervical rib as was formerly supposed, but are trophic lesions of the sympathetic (vasomotor) nerves. The vasomotor nerves to the arm mainly come from the second thoracic root by the communication it gives to the lowest cord of the brachial plexus, and so are exposed to pressure from the rib.
The same investigator has shown that similar symptoms may be produced occasionally by a first thoracic rib in cases where the brachial plexus has migrated caudad. In the living patient, unless a radiogram be taken showing all the vertebroe up to the base of the skuU, it is not possible with precision to ascertain with which vertebra the highest rib present articulates.
Structures found in an intercostal space. — (1) Skin; (2) superficial fascia, with cutaneous vessels and nerves; (3) deep fascia; (4) external intercostal; (5) cellular interval between intercostals, containing trunks of intercostal vessels and nerves; (6) internal intercostals; (7) thin layer of fascia; (8) subpleural connective tissue; (9) pleura (fig. 1106).
The intercostal arteries are nine aortic and two from the superior intercostal. An aortic intercostal having given off its dorsal branch, lying beneath the pleura, crosses the space obliquely upward to gain the lower border of the rib above, enters the costal groove at the angle, and runs forward between the intercostal muscles to anastomose with the anterior intercostals from the internal mammary or musculo-phrenic. Hence the rule of making the incision in empyema above the upper margin of the lower rib and in front of the angle. Along the dorsal branch a vertebral abscess may track backward.
Internal mammary artery.- — This descends behind the clavicle, the costal cartilages, and the first six spaces, about 1.2 cm. (| in.) from the edge of the sternum. In the sixth intercostal space it divides into musculo-phrenic and superior epigastric acteries. Its vense comitantes uniting join the innominate vein of the same side. A punctured wound of the artery is most easily secured in the second and third spaces; below, resection of part of a costal cartilage will be needed.
upper part of the first thoracic vertebra, the following structures are met with : — (1) In the middle line. Sterno-hyoid and sterno-thyreoid muscles, with their sheaths of deep cervical fascia, cellular tissue in which are the remains of the thymus gland, the inferior thyreoid veins, the trachea and tracheal fascia, the oesophagus, and longus colli muscles. Between the trachea and oesophagus are the recurrent nerves. (2) On each side. The apex of the lung, covered by pleura, deep cervical fascia, and membranous cervical diaphragms ("Sibson's fascia") derived from the scalenes, rises about 3.7 cm. (1| in.) above the first rib. Between it and the trachea and oesophagus lie the following : the internal mammary artery, the phrenic nerve; on the right side, the innominate vein and artery, with the vagus between the two, the cardiac nerves, and the right lymphatic duct. On the left side are the common carotid and subclavian arteries, with the left vagus between them, the cardiac nerves and the thoracic duct. Farthest back and on each side are the trunk of the sympathetic, the superior intercostal artery, and the first thoracic nerve.
The mamma. — This lies chiefly on the pectoralis major and slightly on the rectus abdominis and serratus anterior. It is usually described as reaching from the second to the sixth rib, and from the sternum to the anterior border of the axilla. It is most important to remember that the breast is often a much more extensive structure than would be included in the above very limited description. Thus — (1) the gland is not encapsuled at its periphery, its tissue branching and breaking up here to become continuous with the superficial fascia. (Stiles.) (2)
The retinacula cutis contain lymphatics and, sometimes, mammary tissue. (3) There is a lymphatic plexus, and, often, minute lobules of gland tissue, in the pectoral fascia. (Heidenhain.) Fully one-third of the whole mamma lies posterior and lateral to the axillary border of the pectoralis major so that it reaches almost to the mid-axillary line. That part of the upper and lateral quadrant known as the axillary lobe is of especial importance from its reaching into close vicinity with the anterior pectoral group of axillary nodes (p. 719). In the male the nipple is usually placed in the fourth space, nearly 2.5 cm. (1 in.) lateral to the cartilages of the fourth and fifth ribs. On the nipple itself open the fifteen or twenty ducts which dilate beneath it, and then diverge and break up for the supply of the lobules. The skin over the areola is very adherent, pigmented, and fatless. Here also are groups of little swellings corresponding to large sebaceous follicles and areolar glands. The skin over the breast is freely movable, and united to the fascia which encases the organ, and thus to the interlobular connective tissue, by bands of the same structure — the retinacula cutis. Under the breast, and giving it its mobility, is a cellulo-fatty layer, the seat of submammary abscess.
' The nerves which supply the breast are the anterior cutaneous branches of the second, third,' foui'th, and fiftli intercostal nerves, and the lateral branches of the last three. The connection of tliese trunliS serves to explain the diffusion of the pain often observed in painful affections of the breast. Thus pain may be referred to the side of the chest and bacli (along the above intercostal trunks), over the scapula, along the medial side of the arm (along the intercosto-brachial nerve), or up into the neck. The gland is supplied by the following arteries : the aortic intercostals of the second, third, fovirth, and fifth spaces, similar intercostal branches from the internal mammary, which runs outward, two small branches to each space, perforating branches from the same vessel, one or two given off opposite to each space, the long thoracic and external mammary (when present) from the axillary.
In removal of the breast elliptical incisions will usually suffice if employed on wide lines, and if attention be paid to the following points: — (1) Those details in the surgical anatomy already referred to, especially those bearing on the extensiveness of this organ, and the proportionate difference between seen and unseen disease. (2) The importance of removing in one continuous piece the whole breast, all the skin over it, the costo-sternal part of the pectoralis major, the pectorahs minor, the axillary fat, and lymi^hatics.
Outline of the lungs. Their relation to the chest-wall. — To map out the lung, a line should be drawn from the apex, a point about 2.5 cm. (1 in.) above the clavicle, a little lateral to the sterno-mastoid muscle, at the junction of medial and middle thirds of clavicle, obliquely downward, behind the sterno-clavicular joint, to near the centre of the junction of the first and second bones of the sternum. Thence, on each side, a line should be drawn slightly convex as far as a similar point on the sternum lying opposite the articulation of the fourth chondrosternal joint. On the right side the line may be dropped as low as the sixth chondro-sternal joint; on the left the incisura cardiaca may be shown by drawing a vertical line along the middle line of the sternum, from the level of the medial extremities of the fourth costal cartilages to the lower end of the gladiolus, and
by carrying two other lines, from the extremities of the first line, outward so as to meet at a point over the heart's apex (Cunningham); to mark this gap, a line should be drawn sloping laterally and downward from the fourth chondrosternal articulation across the foui'th and fifth interspaces, to a point about 3.7 cm. (1| in.) below the left nipple (male) and 2.5 cm. (1 in.) to its medial side. This point, lying in the fifth space, marks the apex of the heart. Thence the line curves medially to the sixth costal cartilage, a little medial to its chondrosternal junction, and in the lateral vertical line. Thus the lower part of the anterior surface of the right ventricle is not covered by lung. The lower border of the lung will be marked on the right side by a line drawn from the sixth chondrosternal articulation across the side of the chest down to the tenth thoracic spine. The lower border of the left lung will follow a similar line, starting on a level with a similar joint (sixth chondro-sternal joint), but much farther laterally than on the right side, i. e., in the fifth space, about 7.5 cm. (3 in.) to the left of the middle line, or a point corresponding to the heart's apex. In the nippleline the lung crosses the sixth rib, in the mid-axillary line the eighth, and opposite
the angle of the scapula (the arms being close to the sides), the tenth rib. The position of the great fissure in each lung may be ascertained approximately by drawing a line curving downward and forward from the second thoracic spine to the lower border of the lung at the sixth costal cartilage; and the smaller fissure of the right lung extends from the middle of the foregoing to the junction of the fourth costal cartilage with the sternum. It will be seen from the above that there is little lung behind the manubrium. The connective tissue here between the lung margins contains the thymus, large up to the age of puberty, and, later, its remains. The hilus (root) of the lung is referred to on p. 1230.
The pleura, following much the same line as the lung above and in front, reaches lower clown laterally and behind. Thus the two sacs starting from about 2.5 cm. (1 in.) above the medial third of the clavicle converge toward the angle of Louis (p. 1238) ; meeting here, they descend vertically, the left overlapping the right slightly, to the fourth chondro-sternal joint. Hence the right sac descends behind the sternum to the sterno-xiphoid junction and sixth chondro-sternal joint. Thence, as it curves to the back of the chest, it crosses the eighth rib close to the lateral vertical line {vide supra), the tenth in the mid-axillary, the eleventh in the line of the angle of the scapula, and thence toward the twelfth thoracic vertebra. On the left side the pleura parts company from the right at the level of the fourth chondro-sternal junction, deviating laterally and downward across the fourth and fifth interspaces; it then turns again slightly medially to meet the sixth costal cartilage. Thus, as in the case of the lung, but to a less extent, there is a small area of the pericardium, and, under it, the right ventricle uncovered by the pleura. Over the side and back of the chest, along its diaphragmatic reflection, the left pleura reaches a little lower than the right.
The deepest part of the pleural sac is where the reflection crosses the tenth rib or tenth space in the mid-axillary line. From this it ascends slightly as it curves back to the spine. (Cunningham.) The relations of the pleura to the last rib are of much importance to the surgeon in operations on the kidney. In the case of a twelth rib of ordinary length, the pleural reflection crosses it at the lateral border of the sacro-spinalis ; when a rudimentary last rib does not reach the lateral border of this muscle, an incision carried upward into the angle between the eleventh rib and the sacro-spinalis will open the pleural sac. (Melsome.)
For tapping the pleura there are two chief sites: — (1) The sixth or seventh space in front of the posterior fold of the axilla. (2) The eighth space behind, in the line of the angle of the scapula. For the incision of an empyema the first is usually chosen. The overlying soft parts are not thick, the interspace is wide enough, drainage is sufficient (especially if part of the seventh or eighth rib be resected), and this site is free from the objection that the angle of the scapula overlaps the seventh and eighth ribs, unless the arm is raised.
Outline of the heart. Its relation to the chest-wall. — The upper limit of the heart (base) will be defined by a line crossing the sternum a little above the upper border of the third costal cartilage, reaching about 1.2 cm. (J in.) to the right and about 2.5 cm. (1 in.) to the left of the sternum. Its apex point is in the fifth space, 3.7 cm. (1| in.) below the male left nipple, and 2.5 cm. (1 in.) to the medial side. This point will be at 7.5 cm. (3 in.) from the left border of the sternum. The right border (right atrium) will be given by a line, slightly convex laterally, drawn from the right extremity of the upper border to the right sixth chondro-sternal joint. If another line, slightly convex upward, be drawn onward from this point across the last piece of the sternum, just above the xiphoid cartilage, to the apex, it will give the lower border (margo acutus of right ventricle), which rests on the central tendon of the diaphragm. The left border (margo obtusus of left ventricle) will be given by a line, convex to the left, passing from the left extremity of the upper border to the apex, medial to the nippleline. This line should be 7.5 cm. (3 in.) from the middle of the sternum at the level of the fourth costal cartilage. The base of the heart is opposite four of the thoracic vertebrae, viz., the sixth, seventh, eighth, and ninth. The apex and anterior or costo-sternal surface have been mentioned. The inferior or diaphragmatic surface (chiefly left atrium and left ventricle) rests upon the diaphragm, mainly the central tendon, to which the intervening pericardium is connected, and is thus adjacent to the liver and a small portion of the stomach.
If a circle 5 cm. (2 in.) in diameter be described around a point midway between the left nipple and the lower end of the gladiolus, it will define with sufficient accuracy for practical purposes that part of the heart which lies immediately behind the chest wall, and which is uncovered by lung and (in part) by pleura. (Latham.)
THE HEART 1369
The valves. — The pulmonary valves (the highest and most superficial) lie, in front of the aortic, behind the third left chondro-sternal joint, and opposite to the upper border of the third costal cartilage. The aortic valves lie behind and a little below these, opposite to the medial end of the third intercostal space, and on a level with the lower border of the third left costal cartilage. The atrio -ventricular openings lie at a somewhat lower level than that of the aortic and pulmonary. Thus the tricuspid valves lie behind the middle of the sternum at the level of the fourth intercostal space; and the mitral valves, the most deeply placed of all, lie a little to the left of these, behind the left edge of the sternum and the fourth left costal cartilage (fig. 1107; also cf. fig. 437).
'Thus these valves are so situated that the mouth of an ordinary-sized stethoscope will cover a portion of them all, if placed over the juncture of the third intercostal space, on the left side, with the sternum. All are covered by a thin layer of lung; therefore we hear their action better when the breathing is for a moment suspended.' (Holden.)
The pericardium. — This fibro-serous sac, occupying the middle mediastinum, is triangular in shape, with the apex upward. Here its fibrous layer gives mvestment to the large vessels, except the inferior cava. It is also continuous with the deep cervical fascia. The base, connected with the diaphragm, has been referred to above. In front an area of variable size (fig. 1107), owing to the divergence of the left pleura, is in contact with the left half of the lower part of the sternum, and more or less of the medial ends of the fourth, fifth, and sixth costal cartilages, here forming the posterior boundary of the anterior mediastinum. Behind, the pericardium is the anterior boundary of the posterior mediastinum, and is in close contact with the oesophagus and aorta.
Paracentesis of pericardium. — While the seat of election must here remain an open question, each case requiring a decision for itself, the one most suitable on the whole is the fifth left space, about 2.5 cm. (1 in.) from the sternum, so as to avoid injury to the internal mammary artery and the pleura, of which the line of reflection has been shown to vary.
In incision of the pericardium to establish free drainage, a portion of the fifth or sixth left costal cartilage should be carefully resected, the internal mammary artery tied, the transversus thoracis (triangularis sterni) scratched through, and the pleural reflexion pushed aside.
Relation of vessels to the wall of the thorax. — Aortic arch. — The ascending part of the aorta reaches from a spot behind the sternum, a little to the left of the centre, on a level with the third left costal cartilage, to the upper border of the second right cartilage; thus it passes upward, backward, and to the right, and is about 5 cm. (2 in.) long. The transverse part then crosses backward to the left behind the sternum (the highest part of the arch being about 2.5 cm. (1 in.) below the notch), reaching from the second right costal cartilage to the lower border of the fourth thoracic vertebra on the left side. This part recedes from the surface, and, with the next, cannot be marked out on the surface. The third, or descending part, the shortest of the three, reaches from the lower border of the fourth to that of the fifth thoracic vertebra.
Fig. 1104 will remind the reader of many of the pressure symptoms which may accompany an aneurysm of the aortic arch; e. g., pressure on the left innominate vein, the three large arteries, trachea, and left bronchus, recurrent nerve, oesophagus, and thoracic duct. In aneurysm of the thoracic aorta, pain, usually unilateral, referred to the corresponding intercostal nerves, is a common pressure symptom.
clavicular joint.
Left subclavian artery. — A line from the end of the transverse arch, behind the left of the sternum, straight upward to the clavicle, delineates the vertical thoracic course of the long left subclavian artery; its thoracic portion lies behind the left carotid.
Innominate veins. — The left, 7.5 cm. (3 in.) long, extends very obliquely from the left sterno-olavicular joint, behind the upper part of the manubrium, to a point 1.2 cm. (| in.) to the right of the sternum, on the lower border of the first right costal cartilage. The right, about 2.5 cm. (1 in.) long, descends almost vertically to the above point from the right sternoclavicular joint.
Venae cavae. — The superior descends from the point above given for the meeting of the innominate veins in the first intercostal space, close to the sternum, and perforates the right atrium on a level with the third costal cartilage. The inferior vena cava. — The opening of this vein into the right atrium lies under the middle of the fifth right interspace and the adjacent part of the sternum.
The oesophagus. — The relations of this tube in its cervical and thoracic portions are most important, e.g., to the trachea and left bronchus; the vagi and left recurrent nerve; the pleurae, left above and right [below, aorta, and
nostic in malignant disease.
The lumen of the oesophagus is narrowed at three points: — (1) and best marked at the cricoid cartilage, (2) where it is crossed by the left bronchus, (3) as it passes through the diaphragm. The tube, 25 to 27 cm. (10 to 11 in.) long, extends from the sixth cervical to the lower ■ border of the tenth thoracic vertebra. In an adult, the distance from the incisor teeth to the cricoid is about 15 cm. (6 in.); an additional 7.5 cm. (3 in.) gives the level of the crossing of the left bronchus, while from the teeth to the opening in the diaphragm would be from 41 to 43 cm. (16 to 17 in.). To expose the tube in the neck an incision is made on the left side, much as for the higher ligature of the common carotid, but carried lower down. The depressors of the hyoid being drawn medially or divided, the pretracheal fascia is opened, which allows of the overlapping thyreoid and trachea being displaced medially, while the carotid sheath is retracted laterally. The tracheal rings are the best guide to the oesophagus. The recurrent nerve must be avoided.
organs.
Subdivision of the abdominal cavity. — Certain arbitrary horizontal and vertical planes, represented by lines drawn on the ventral surface, are used to subdivide the abdomen for topographical purposes (fig. 898). A. Horizontal planes. (1) Infracostal through the lower margins of the tenth costal cartilages (the lowest part of the costal margin). This plane crosses the body of the third lumbar vertebra. (2) Intertuhercular, passing through the tubercles, prominent points of the ihac crests, which are situated about 5 cm. (2 in.) behind the anterior superior spines. This plane crosses the body of the fifth lumbar vertebra. B. Vertical planes. (1) Median vertical, drawn upward in the middle line from the symphysis pubis. (2) Lateral vertical, drawn upward on each side parallel to the former, from a point midway between the anterior superior iliac spine and the symphysis pubis.
According to the BNA system, the lateral vertical lines are slightly curved, extending upward from the pubic tubercle on each side along the lateral margin of the rectus muscle (corresponding to the linea semilunaris).
The infracostal and intertuhercular planes, with the two lateral vertical planes that intersect them divide the abdomen into nine regions: — three median, viz., the epigastric, umbilical, and h3rpogastric and on each side three lateral, viz., hypochondriac, lumbar, and iliac (fig. 898).
Another transverse plane of practical importance, though we do not use it as a boundary of the abdominal subdivisions, is represented by Addison's transpyloric line, drawn horizontally through a point midway between the umbilicus and the sterno-xiphoid junction (or midway between the symphysis pubis and supra-sternal notch). It crosses the spine at the level of the first lumbar vertebra. It must be noted that the pylorus only lies in this plane during life when the subject is in the horizontal position. On assuming the upright position the pylorus falls at least one vertebra lower. The sterno-xiphoid plane, drawn horizontally through the junction of the body of the sternum with the xiphoid, outs the spine at the disc between the ninth and tenth thoracic vertebrte, and the umbilical plane, passing through the umbilicus, crosses the disc between the third and fourth lumbar vertebrae (though in corpulent subjects it is somewhat lower).
forms a perceptible groove in the middle fine from the xiphoid cartilage to below the umbilicus. It is a band of interlacing fibres, mostly crossing each other at right angles, that forms the main insertion of the transversus and oblique muscles, and stretches between the two recti muscles from xiphoid cartilage to symphysis. It is on the average 1.2 cm. (| in.) wide above the umbilicus. Below the umbilicus it narrows rapidly and becomes merely a thin fibrous septum between the two recti, which in this position lie close together.
In its broad supra-umbilical portion, small hernial protrusions of subperitoneal fat often force their way through interstices in the linea alba, and true peritoneal sacs may be drawn through after them. The linea alba is not very vascular, and hence was at one time the favour-
THE ABDOMEN 1371
ite site of incisions in opening the abdominal cavity. Since the resulting scar is weak and yielding, however, it is now more customary to make vertical incisions through the rectus sheath, to one side of the middle line, where the abdominal wall can be sutured in layers, and an incisional hernia prevented.
The umbilicus lies in the linea alba rather below its centre. It is somewhat prone to hernia formation (p. 1402) and is occasionally the site of congenital fistulas, which may originate in a Meckel's diverticulum (p. 1376) or a patent urachus.
When the recti are thrown into contraction the linea semilunaris on each side is made evident as a groove, extending with a slight lateral convexity from the tip of the ninth costal cartilage, where the lateral vertical line meets the thoracic margin, to the pubic tubercle.
The contraction of the recti muscles also shows up the three lineae transversae, fibrous intersections adherent to the anterior layer of the sheath of the rectus, which cros.? the substance of the muscle (1) at the umbilicus, (2) at the tip of the xiphoid, and (3) midway between the former two. A tonic contraction of one or both recti localised to one of these segments occasionally gives rise to the "phantom" tumors which occur in some hysterical cases.
The linea semilunaris shares the disadvantages of the linea alba as a site for incisions, and there is the further danger of injury to the nerve supply of the rectus, which may involve a diffuse bulge of the atrophied muscle.
In tapping the bladder above the pubes, the trocar should be introduced immediately above the pubes and driven backward and a little downward. In this operation, and in suprapubic cystotomy, the retro-pubic space or cavum Retzii is opened. This is bounded in front by the pubes and superior fascia of the urogenital diaphragm, behind by the anterior surface of the bladder. Below are the true ligaments of this viscus. The space contains fatty tissue and veins, increasing in size with the advance of life. If about ten ounces of fluid are injected into the bladder, the peritoneum will be raised sufficiently to allow of a three-inch incision being made between the recti and pyramidales immediately above the pubes. The transversalis fascia is thicker below, and is often separated from the linea alba by fat, which must not be mistaken for the extra-peritoneal layer. The peritoneal reflexion is loosely connected to the bladder and can always be peeled upward.
A transverse line drawn from one anterior superior iliac spine to the other crosses at about the level of the top of the promontory of the sacrum. Such a line will always show whether the pelvis is horizontal or not. (Holden.)
The inguinal (Poupart's) ligament corresponds to a line drawn with a slight curve downward between the anterior superior iliac spine and the pubic tubercle. The first of these bony prominences corresponds to the starting-point of the above ligament, the attachment of the fascia lata to the ilium, the meeting of the fleshy and aponeurotic parts of the external oblique (denoted by a line drawn upward from this spine to the ninth costal cartilage, or often a little anteriorly to these points), the point of emergence of the lateral cutaneous nerve of the thigh, and part of the origins of the internal oblique, transversus, and tensor fasciae latae.
The pubic tubercle marks the lateral pillar (inferior crus) of the subcutaneous inguinal (external abdominal) ring, the mouth of which corresponds to the crest of the pubes lying between the tubercle and the symphysis. The neck of an inguinal hernia is above the tubercle and Poupart's ligament; that of a femoral hernia below and lateral to the tubercle, and below the same hgament. The ring, and especially its lateral pillar, can easily be felt by invaginating the scrotal skin with a finger, and pushing upward and laterally. In a female patient, if the thigh be abducted, the tense tendon of tlu' adductor longus will lead up to the site of the ring. The abdominal inguinal (internal abdominal) ring is situated about 1.2 cm. (J in.) above the centre of Poupart's ligament; oval in shape, and nearly vertical in direction, it has the arching fibres of the transversus above it, and to its medial side the inferior epigastric artery, lying behind the spermatic cord. The pulsations of this vessel here guide the finger in the insertion of the uppermost deep sutures in radical cure of hernia. The canal runs obliquely downward and forward between the two rings. In the adult it is about 3.7 cm. (1^ in.) long, but in early life, and in adults with a large hernia dragging upon the parts, the two rings are much nearer, and may be one behind the other. For the anatomy of inguinal hernia see p. 1304.
Vessels in the abdominal wall. — The three superficial branches of the common femoral, the external pudic, epigastric, and circumfiex iliac, supply the lowest part of the abdominal wall and the adjacent groin and genitals. The others that have to be remembered are the inferior epigastrics and the epigastric branch
the abdominal branches of the lumbar arteries.
Of these, the infei'ior epigastric is the most important; its course will be marked out by a line drawn from a point just medial to the centre of the inguinal ligament, upward and medially to the medial side of the abdominal ring, and thence to a point about midway between the pubes and umbilicus, forming the lateral boundary of Hesselbach's triangle (fig. 1121). Here the vessel, which at first lies between the peritoneum and fascia transversalis, perforates the latter and, passing over the semicircular line (fold of Douglas) enters the sheath of the rectus. It then runs upward, closely applied to the back of that muscle, and, a little above the level of the umbilicus, divides into branches which anastomose with the epigastric branch of the internal mammary.
One superficial vein in the abdominal wall needs especial mention, the thoraco-epigastric, joining the veins of the chest, e. g., the long thoracic above with, the superficial epigastric below. Its valves directing the blood downward below and upward above (Stiles) may be rendered incompetent when this vessel is enlarged, as in interference with the portal vein, mth which it communicates by a vein in the round ligament, or in blocking of the inferior vena cava.
to the axillary, and those below that line to the inguinal nodes.
Nerves. — The lower seven intercostals and the ilio-hypogastric and ilioinguinal supply the abdominal wall. The sixth and seventh intercostals supply the skin over the upper epigastrium; the eighth, the area of the middle linea transversa; the tenth, that of the imibilicus ; the last thoracic, ilio-inguinal and iliohypogastric, the region above Poupart's ligament, and that of the pubes. The ilio-hypogastric supplies the skin over the subcutaneous inguinal (external abdominal) ring; the ilio-inguinal that over the cord and scrotum. The last thoracic and ilio-hypogastric cross the iHac crest to supply the skin of the buttock.
The diaphragm. — The upper limit of the diaphragm rises to the following levels in full expiration: Its central tendon to about the lower end of the body of the sternum, or the seventh chondro-sternal joint; the right half to the fifth rib, or about 1 cm. (| in.) below the nipple; the left half not rising quite so high, i. e., to the fifth space, or 2.5 cm. (1 in.) below the nipple.
Topographical relations of abdominal viscera. — These will include the peritoneum, liver and bile passages, stomach, spleen, pancreas, intestines, kidneys and ureters, and large abdominal vessels.
The peritoneal spaces. — The peritoneum presents certain potential spaces, determined by its various reflections from the parietes and abdominal viscera. In these spaces collections of fluid such as abscesses or extravasations from hollow viscera or blood vessels may collect and become shut off by adhesions or overflow in various directions into neighbouring spaces. The transverse mesocolon and great omentum together form a shelf transversely placed, which divides the greater sac into two main divisions — supra-omental and infra-omental.
The supra-omental region, in which the various forms of subphrenic abscess are found, contains the following fossa; (Barnard).* (1) Right subphrenic, between the right lobe of the liver and right cupola of the diaphi-agm, bounded toward the median line by the falciform ligament, and behind by the coronary ligament. It communicates below with (2) the subhepatic fossa or right renal pouch (Morison), which is bounded above by the visceral surface of the liver, and below by the mesocolio shelf and right kidney. It extends from the right lateral abdominal wall, its most capacious part, across the median line under the left lobe of the liver, and on its posterior aspect lie the upper pole of the right kidney, epiploic foramen, and anterior surface of small omentum. (3) The left subphrenic, also known as the anterior perigastric fossa, lies between the left dome of the diaphragm above, and the left lobe of liver, stomach, spleen and omentum below. It is bounded on the right by the falciform ligament which lies somewhat to the right of the median line. (4) The omental bursa may be regarded as a diverticulum from the subhepatic fossa with which it communicates by the epiploic foramen. Abscesses in this sac are rare, but occasionally laceration of the pancreas which is closely related to it behind gives rise to a collection of pancreatic juice and blood in the lesser sac, known as a pancreatic pseudo-cyst (Jordan Lloyd).
The infra-omental region is subdivided in its abdominal part into (1) right and (2) left compartments by the attachment of the root of the mesentery to the spine, descending from the duodeno-jej unal flexure downward into the right iliac fossa. These fossae communicate with the supra-omental regions in the neighbourhood of the hepatic and splenic flexm-es of the colon respectively, and below with (3) the pelvis. The deepest level of the peritoneum lining the pelvis constitutes in the male the recto-vesioal, and in the female the recto-vaginal fossa (pouch of Douglas).
It should be noted that with a patient in the supine position, owing to the contour of the psoas muscles and the anterior convexity of the lumbar spine, any fluid above the pelvic brim will tend to gravitate into the subphrenic spaces across the flexures of the colon which lie far back in the loins. This is undesii-able in view of the great absorbing power of the subphrenic lymphatics, and may be obviated by propping the patient in a half-sitting position.
Viscera behind the linea alba. — From above downward there are the following:— (Ij Above the umbiUcus — the left lobe of the liver, the stomach, the transverse colon, part of the great omentum, the pancreas, and cceliac (solar) plexus. (2) Below the umbilicus — the rest of the great omentum, covering in the small intestines and their mesentery. In the child, the bladder occupies a partly abdominal position; and in the adult, the same viscus, if distended, will rise out of the pelvis and displace the above structures, raising the peritoneum until, if distended half way to the umbilicus, there is an area of nearly 5 cm. (2 in.) safe for operations above the symphysis. The gravid uterus also rises behind the linea alba.
The liver (figs. 914, 941, and 1125). — In the erect position, the anterior thin margin of the liver projects about 1 cm. (| in.) below the costal cartilages, but can only be made out with difficulty in this position. It may also be displaced downward by pleuritic effusion or tight lacing. The liver is also, proportionately, much larger in small children.
Of the three more accessible surfaces, the right lateral is opposite the seventh to the eleventh intercostal arches, separated from them by the pleura, the thin base of the lung, and the diaphragm. The superior surface is accurately fitted with its right and left portions into the hollows of the diaphragm, a slightly depressed area intervening which corresponds to the central tendon. Its level corresponds to that of the diaphragm given above. On the left side, in the adult, the limit of the left lobe will be in the fifth interspace, about 7.5 cm. (3 in.) from the sternum. The antericr surface is in contact with the diaphragm, costal arches, and, between them, the xiphoid cartilage, and, below, with the abdominal wall. Both the superior and anterior siu'faoes are subdivided by the falciform ligament, an important point in subphrenic suppuration. In the right hypochondrium the anterior margin corresponds to the lower margin of the thorax; but in the epigastric region, running obhquely across from the ninth right to the eighth left costal cartilage, it crosses the middle line about a hand's breadth below the sternoxiphoid articulation (Godlee), or half-way between the sterno-xiphoid j unction and umbiUcus, i.e., in the transpyloric line (fig. 914). Behind, the anterior margin, following the right lateral surface within the costal arches, crosses the last rib toward the level of the eleventh thoracic spine. In the anterior border, a little to the right of the median vertical plane, is the umbilical notch, where the falciform and round ligaments meet. Still further to the right, and just to the left of the mid-Poupart plane, is the fundus of the gall-bladder.
Gall-bladder and bile passages. — The fundus of the gall-bladder, situated in a fossa on the under surface of the right lobe of the liver, and having the quadrate lobe to its left, lies opposite to the right ninth costal cartilage, close to the lateral edge of the rectus. This point corresponds to the site of intersection of the lateral vertical and transpyloric lines. It is in contact with the hepatic flexure of the colon and the first piece of the duodenum, into either of which, but particularly the latter, large gall-stones impacted in the neck of the gall-bladder occasionally ulcerate. A distended gall-bladder as it enlarges tends to take a line obliquely from the above point where it emerges from under the costal margin toward the umbilicus.
The long axis of the gall-bladder is directed from the fundus backward and upward. The cystic duct runs from the neck downward and forward in the gastro-hepatic omentum, and so forms an acute angle with the gall-bladder. A spiral fold of mucous membrane at the junction of the two, which fulfils the function of keeping the lumen open for the flow of bile, adds to the difficulty of passing a bougie from the gall-bladder down into the common duct.
The hepatic and cystic ducts join in the right free margin of the gastro-hepatic omentum to form the common bile-duct, 7.5 cm. (3 in.) in length, which as it runs down to open into the duodenum presents four distinct stages. (1) It first lies in the free edge of lesser omentum in front of the epiploic foramen, with the hepatic artery to the medial side, and the portal vein behind them both. (2) Behind the first part of the duodenum with the gastro-duodenal artery accompanying it. (3) In a deep groove in the head of the pancreas, between that gland and the posterior aspect of the second part of the duodenum. The pancreatic tissue siurounds it completely in 75 per cent, of cases, (Bunger) hence the jaundice that occurs in chronic interstitial pancreatitis. (4) Piercing the muscular waU of the duodenum obliquely it ends by joining the main duct of the pancreas at the ampulla of Vater and opening into the second part of the duodenum by a common orifice. This orifice, situated on the postero-medial aspect of the gut, rather below the centre of the second portion, is raised on a small papilla and is narrower than the lumen of the common duct.
The stomach. — The study of this organ by rendering its contents opaque with bismuth salts and projecting its shadow by X-rays on a fluorescent screen, has greatly modified the conception of its shape and position formed from postmortem and operative observations. Examined post-mortem, or at operations under general ansesthesia it forms a flaccid sac with its long axis directed from the fundus obliquely downward, forward, and to the right. Seen under X-rays,
with the patient standing upright, the cardiac portion (the fundus and body together) is vertical, and the smaller pyloric portion is directed backward and to the right and slightly upward (fig. 1125). The most fixed point is the cardiac orifice.
The cardiac orifice lies under the seventh left costal cartilage 2 cm. (f in.) from the sternoxiphoid junction at a depth of about 10 cm. (4 in.) from the surface. Behind, this point corresponds to the tenth thoracic vertebra.
when"any transient faintness or nausea causes loss of muscular tone (Barclay). The pylorus is slightly to the right of the middle line in the empty stomach. As the stomach fiUs it descends farther and moves a little farther to the right. The lesser curvature presents a definite notch at the junction of the cardiac and pyloric portions of the stomach — the incisura angularis.. The greater curvature reaches the umbihoal plane in the erect posture, even when the stomach is empty. When the viscus is full tliis curvature lies distinctly below this plane, being lower in women than in men (Hertz). The ■pyloric portion of the full stomach is directed backward and a httle upward, as the distended pyloric vestibule moves further to the right than the pyloric orifice and lies on an anterior plane. In the recumbent posture the greater curvature hes above the umbihcal plane, even when moderately distended, and the stomach is more obliquely placed. The fundus invariably contains gas, even when the stomach contains no food, in which case the organ forms a contracted J-shaped tube (fig. 1108). In extreme distention the left dome of the diaphragm is so pushed up by the fundus that it lies at a level as high as or even higher than the
right dome (Hertz). The pressure thus exerted on the heart accounts for the dyspnoea and cardiac pain so often associated with flatulence. The position of the pyloric sphincter is shown on the outer surface by a very constant venous ring runrling toward both lesser and greater curvatures in the subserous layer at right angles to the long axis of the pyloric canal (Moynihan).
In connection with the extravasation of contents that results from perforating ujcers of the stomach, a knowledge of the subphrenic peritoneal fossaj is important (p. 1372). Perforation is rare on the posterior surface since it is less mobile than the anterior, and protective adhesions form readily. When it does occur, extravasation into the omental bursa results, and suzih a perforation is exposed by turning up transverse colon and stomach and incising the transverse meso-colon. Perforation on the anterior surface usually gives rise to general peritonitis, but in the less sarious cases an abscess may form localised to (l) the right subphrenic space, (2) the subhepatic fossa, or (3) the left subphrenic space, according to the situation of the ulcer on the stomach.
The Spleen (fig. 1127; see also figures in Sections IX and XII). — This lies very obliquely in the left hypochondrium, its long axis corresponds closely with the line of the tenth rib. It is placed opposite the ninth, tenth, and eleventh ribs externally, being separated from these by the diaphragm; and medially it is connected with the great end of the stomach. Below, it overlaps slightly the lateral border of the left kidney (fig. 1127). Its highest point is on a level with the spine of the ninth thoracic, and its lowest with that of the eleventh thoracic vertebra. Its upper pole is distant about 3.7 (1| in.) from the median plane of the body, and its lower pole about reaches the mid-axillary line on the same rib. (Godlee.) In the natural condition it cannot be felt; but if enlarged, its notched anterior margin extends downward toward the umbilicus, and is both characteristic and readily felt.
The pancreas. — The head of the pancreas lies in the hollow formed by the three parts of the duodenum, on the bodies of the second and third lumbar vertebrae. The inferior vena cava lies behind it. The neck, body, and tail of the pancreas pass obliquely to the left and slightly upward, crossing respectively the commencement of the portal vein, the aorta, and the left kidney. The root of the transverse mesocolon is attached to the anterior margin of the gland, so that its supero-anterior surface is related to the omental bursa, and its inferior surface to the greater sac. The importance of this relation in the formation of pancreatic pseudo-cysts has been referred to above.
Pancreatic ducts. — The main duct, the duct of Wirsung, opens into the common ampulla of Vater with the bile duct. This ampuUa usually opens into the gut by a narrow orifice raised on a small papilla. A gaU-stone impacted in the ampulla may cause a flow of bile backward along the duct of Wirsung, and so give rise to acute pancreatitis (Opie). The small accessory duct of Santorini opens into the duodenum independently about 2 cm. higher up. It often anastomoses with the larger duct in the substance of the gland.
A cyst originating in the pancreas may "point" toward the anterior abdominal wall by three routes: — (1) Above the stomach through the lesser omentum; (2) between stomach and transverse colon through the great omentum; (3) below the transverse colon through the transverse mesocolon. The posterior aspect of the head of the gland, with the third part of the common bile duct may be exposed by incising the peritoneum on the lateral margin of the second part of the duodenum, and turning the gut medially toward the middle line.
Intestines. (A) Small. — The average length of the small intestine is about 6.85 m. (22| ft.), though the length as measured post mortem varies considerably with the degree of contraction of the longitudinal muscular coat. The duodentma is about 25 cm. (10 in.) in length. Of the remaining portion the upper two-fifths constitute the jejunum and the lower three-fifths the ileum, though this division is quite arbitrary. Cases are recorded in which patients have survived the removal of over 5 m. (16 ft.) of small intestine.
The first part -of the duodenum extends from the pylorus on the first or second lumbar vertebra, backward and to the right. It ends near the upper pole of the right kidney and on the medial side of the neck of the gaU-bladder, by turning down to form the less mobile second -part, which descends in front of the hilum of the right kidney to the level of the third lumbar vertebra. The third part of the duodenum crosses the body of the third lumbar vertebra horizontally in the infracostal plane, and then turns up obliquely to the left side of the spine and ends at the level of the upper border of the second lumbar vertebra in the duodeno-jejunal flexure. The first part is the most mobile, since it is covered back and front by peritoneum in the first half of its course. The second part has a peritoneal covering in front onlj' and is devoid of it where it is crossed by the commencing transverse colon. The third part is covered by peritoneum in front except where the superior mesenteric vessels pass across it to join the commencement of the mesentery. It is probably the constricting effect of these vessels on the duodenum that gives rise to the acute dilatation of the stomach which occasionally follows abdominal operations.
The duodeno-jejunal flexure, which hes on the left side of the body of the second lumbar vertebra, immediately below the body of the pancreas, is held up to the right crus of the diaphragm by a band of fibro-muscular tissue known as the suspensory ligament of Treitz. Some of the fibres of this structui-e are continued onward into the root of the mesentery. It is not found in pronogxade animals. The duodeno-jejunal flexure is the commonest site of traumatic rupture of the small intestine, since it is the point of union of a fixed and a freely movable portion of the gut.
In the operation of posterior gastro-enterostomy the duodeno-jejunal flexm'e is readily found by passing the hand along the under surface of the transverse meso-colon to the left side of the spine, the omentum and colon being turned upward. The first coil of the jejunum is anastomosed to the posterior wall of the stomach, which is exposed by making an opening in the transverse meso-colon.
In some cases the first few centimetres of the jejunum are found to be fused between the layers of the transverse meso-colon. Certain peritoneal fossas are often found on the left side of the flexure. They may give rise to retro-peritoneal hernia and strangulation of intestine. The duodenal fossaj are described on p. 1164.
Jejunum and ileum. — The mesentery contains between its two peritoneal layers the superior mesenteric vessels and their intestinal branches, the superior mesenteric plexus, lacteals and many lymph nodes on their course. These nodes are frequently enlarged in abdominal tuberculosis in children (tabes mesenterica) . The attached border of the mesentery may be marked out on the surface by a line drawn from just below the transpyloric plane and a little to the left of the middle line (the duodeno-jejunal flexure), which curves downward and to the right to end in the iliac fossa at the junction of the intertubercular and right lateral vertical lines (the ileo-caecal valve).
Meckel's diverticulum which is present in about 2 per cent, of subjects (Treves) is found in the free border of the ileum 30 cm. to 1 m. (1 to 3 ft.) above the ileo-caecal valve. It is a remains of the vitello-intestinal duct. It is usually a blind conical pouch some 6 to 9 cm. long with a free extremity, but may be attached to the umbihcus by a fibrous cord. This cord may cause acute intestinal obstruction by strangulating a coil of gut, or the diverticulum may be invaginated and form the starting-point of an intussusception.
to this part of the gut.
Intestinal localisation. — It often happens that the surgeon wishes to ascertain roughly to what part of the small intestine a given coil presenting in a wound belongs. The variations in length of the small intestine and the considerablf range of movement of the coils during peristalsis render the problem difficult, but it may be stated as a general rule that the upper third of the intestine lies in the left hypochondrium and is not usually encountered in a wound; the middle third occupies the middle part of the abdomen, and the lower third lies in the pelvis and right iliac fossa (Monks). The jejunum is thicker walled and more vascular than the ileum. The lumen steadily diminishes as we pass downward, hence foreign bodies such as gall-stones that pass through the jejunum are apt to become impacted in the lower ileum.
The most reliable indications of the level of a given coil are found, however, on inspection of the mesentery and its blood-vessels (see fig. 482 in Section V). Opposite the upper part of the bowel the mesenteric arteries are arranged in a series of large primary anastomosing loops. From these the vasa recta run to the gut 3 to 5 cm. long, straight and unbranched. Passing downward toward the lower end, the single large primary loops give place to smaller and more numerous secondary loops arranged in layers coming nearer and nearer to the bowel. Hence the vasa recta become shorter. They become also less regular and more branched, and in the lower third of the small intestine are less than 1 cm. in length. The mesenteric fat in the upper third never reaches quite to the free edge of the meusentery, so that clear transparent spaces are left near the bowel. In the lower third the fat usually occupies the whole of the mesentery right up to the intestine, and makes it thicker and more opaque.*
The average width of the mesentery, from its root at the posterior parietes to the bowel is 20 cm. (8 in.) and the longest part lies between 2 and 8 m. from the duodenum (Treves). The ileum is freely movable on a long mesentery down to the ileo-C£ecal region. In some cases however a congenital fusion of the leit half of the mesentery with the parietal peritoneum near the pelvic brim binds the bowel down a few inches above the ileo-ca3cal valve, and has been said to give rise to symptoms of intestinal stasis. (Flint,! Gray, and Anderson.)
(B) Large intestine. Ileo-csecal region. — The position of the ileo-csecal valve may be marked on the surface by the junction of the intertubercular and right lateral vertical lines, though it is often found considerably lower. It is situated on the postero-medial aspect of the caecum. The caecum, which is the
blind extremity of the colon lying below the horizontal level of the ileo-caecal valve, is approximately 6.2 cm. (2| in.) in both vertical and transverse diameters, though its size varies much with the degree of distention. It lies usually in contact with the anterior abdominal wall above the lateral half of the inguinal ligament. The orifice of the appendix (vermiform process) lies some 2 cm. below the ileo-cEecal valve. The caecum is completely covered by peritoneum as a rule, though exceptionally its posterior surface is bound down in the right iliac fossa.
The axial rotation of the midgut and descent of the OEeeum that normally take place dui'ing intra-u,terine life (p. 1168) are occasionally not completed, with the result that the cfficum and appendix may be found above and to the left of the umbilicus, or less uncommonly just below
the right lobe of the liver (3 per cent., Alglave), when an attack of appendicitis may simulate inflammation of the gall-bladder. On the other hand certain cases occur in which the CEBCum descends unusually far, proceeding downward and medially until it becomes a pelvic organ whenever the bladder and rectum are empty. This pelvic position of the ca;cum is found in 10 per cent, of infants (G. M. Smith).*
In the commonest form of intussusception, the ileo-caecal valve and lower ileum are prolapsed into the colon and carried down by the force of peristalsis toward the anus. The valve in these cases forms the apex of the intussusceptum, however far it travels.
The vermiform process (appendix) is developed at the apex of the caecum, and persistence of the apical appendix of foetal type, is not uncommon. The fact that all three tsenis coli converge at the base of the appendix is an anatomical reminder of its primitive position. The anterior tsenia is of great service in operations on the appendix, since by following it down from the colon the base of the appendix can alwaj^s be found. The adult position of the base of the appendix on the postero-medial aspect of the caecum is due to the disproportionate growth of the lateral saccule of the caecum which comes to form the apparent caecal apex.
The appendix averages 10 cm. (4 in.) in length in the adult. The position of its base only is at all constant. It lies distinctly below MoBurney's point, which is midway between the umbilicus and the right anterior superior iliac spine. This point is often the seat of greatest tenderness in appendicitis. The appendix itself may be found (1) pointing upward and to the left toward the spleen, behind the terminal ileum and mesentery; (2) hanging over the pelvic brim, in which position tenderness on rectal examination or pain on micturition results when the organ is inflamed; (3) in the retro-colic fossa; and (4) with its tip projecting to the right of the csecum in the right lateral paracolic fossa, where it causes tenderness when inflamed close to the anterior superior ihac spine. The course and to some e.xtent the gravity of abscesses originating in the appendix will depend upon the position the inflamed organ is occupying at the time of perforation.
The artery of the appendix derived from the posterior branch of the ileo-eoUo reaches it by running down behind the end of the ileum. It raises a fold of peritoneum called the mesenterioluin or mesoappendix. Very rai-ely the artery comes from the anterior branch of the ileo-colic.
The tmnice coli referred to above as converging on the base of the appendix contribute its longitudinal muscular coat. The inner circular coat is thicker, but along the attachment of the mesenteriole certain gaps for the passage of lymph and blood-vessels occur in the muscular coats. Through these gaps infection may easily spread from the mucosa to the peritoneum (Lockwood).
The appendix is essentially a lymph gland and has been called the "abdominal tonsil." The lymph follicles he in the submucosa. They are poorly developed at birth but reach their fuU development within the first few weeks of extra-uterine hfe (Berry).* ObUteration of the lumen is common but is inflammatory in origin, and not, as was once thought, a change normal in advanced age.
Pericsecal fossa. — In addition to the mesentery of the appendix certain other folds of peritoneum are usually present at the ileo-cffical junction: (1) the ileo-colic or anterior vascular fold (fig. 1109) containing the anterior branch of the ileo-cohc arterj^; (2) the ileo-caecal, or bloodless fold of Treves, running from the lower border of ileum onto the ciEcum. The appendix may be in a fossa behind either of these folds. It may also be found in the retro-colic fossa lying behind the cfficum and commencement of ascending colon.
oped before birth.
The ascending colon runs with a slight lateral convexity upward from its junction with the caecum to the hepatic flexure which lies under the ninth right costal cartilage at the level of the second lumbar vertebra and in contact with the anterior surface of the right kidnej^ and the lower surface of the right lobe of the liver. It lies lateral to the right lateral vertical plane. This description is only true of an ascending colon examined by X-raj^s in the recumbent position. When the patient stands up, the flexure sinks to the infracostal plane (third lumbar vertebra) or even lower. As the colon ascends in the angle between the quadratus lumborum and psoas, it also passes backward at an angle of 51° ■ndth the horizontal, as may be seen in a sagittal section through the right half of the abdomen (Coffey). f The caecum and ascending colon are distended as a rule with fluid contents and gas, and form the widest part of the colon.
The variations in the peritoneal attachments of the colon, which are of growing clinical importance, are explained by its mode of development (p. 1179). During intra-uterine Ufe after rotation of the midgut round an axis formed by the superior mesenteric vessels, there is a stage in which the colon has almost assumed its permanent position in the abdomen but is still provided with a free mesocolon for both ascending and descending parts. This represents the normal condition of quadruped mammals. In the normal human individual this stage is transient, and before birth the ascending and descending colons lose their mesenteries by fusion of the posterior layers with the parietal peritoneum. Meanwhile the great omentum, formed by a bulging out of the primitive dorsal mesogastrium, fuses with the transverse colon and its mesocolon. The extent of these processes of fusion varies, particularly as far as the ascending and descending colons are concerned. Thus only 52 per cent, of adults have neither ascending nor descending mesocolons (the normal condition). A mesocolon is found on the left side in 36 per cent, of all cases and on the right side in 26 per cent. (Treves). In only a
small proportion (1.8 per cent., however, does the true primitive type of ascending mesocolon persist, continuous with the mesentery of the small intestine (G. M. Smith). Such an anomaly renders the patient liable to volvulus of the ileo-0£ecal region. In the common types of incomplete fusion of its peritoneal attachments the colon is inadequately adapted to the upright position and is predisposed to ptosis. A layer of peritoneum sometimes found passing downward and medially from the parietes in the right flank onto the front of the ascending colon, known as Jackson's pericolic membrane, is probably due to persistence of an early stage in the development of the great omentum, which passes to the right across the ascending colon to join with the parietal peritoneum before the descent of the cjecum is complete, and so is the most primitive agent in fixing the proximal colon back in the right loin. This membrane is usually associated with a congenitaUy mobile ascending colon (Morle}^.*
At the hepatic flexure the colon bends forward and to the left, leaving the front of the kidney to which it is fixed, and crossing the second part of the duodenum. In the region of the flexure three inconstant peritoneal folds are met with giving it additional attachment to the neighbouring parts, viz., (1) the phreno-colic and less commonly (2) the hepalo-colic and (3) cystocolic hgaments (Testut). Thej' must not be confused with pathological adhesions acquired after birth.
The transverse colon is freely mobile except at its extremities. It crosses the abdomen with a convexity downward and forward, being separated from the anterior abdominal wall in the middle region by the great omentum.
At the mid-line it usuaUy lies near the umbihcal plane in the recumbent posture, considerably lower in the erect, but may be found anywhere from the infra-costal plane to the pubes, depending on the tonicity of the stomach. Its main artery, the middle colic branch of the superior mesenteric, must be avoided carefully in the operations of gastro-enterostomy and gastrectomy, since hgature of it causes gangrene of the transverse colon.
The splenic flexure lies far back in the left hypochondrium and is considerably higher than the hepatic flexure. It is in contact with the lower end of the spleen, and is almost invariably held firmly in position by its -phreno-colic ligament, derived from the left extremity of the great omentum.
The descending colon is of narrower calibre than the preceding parts and usually is found firmly contracted and empty. It passes downward and forward in the angle between the psoas and quadratus lumborum and obliquely across to the right the iliac fossa to end in the sigmoid or pelvic colon. The lower part of the descending colon, from the iliac crest to the pelvic brim, is often termed the iliac colon.
In its upper part it hes in front of the convex lateral margin of the left kidney. The variations in its peritoneal attachments have been referred to above (p. 1242). The operation of lumbar colostomy, common in pre-antiseptic days, was performed through an incision in the back parallel with the last rib. The colon lies 2.5 cm. (1 in.) to the lateral side of the edge of the sacro-spinalis, between the twelfth rib and ihac crest. The occurrence of a mesocolon here was a common source of difficulty in gaining access to the bowel without opening the peritoneum.
The pelvic colon (also known as the sigmoid or omega loop (Treves), is almost as long as the transverse colon, and forms a loop, the two ends of which, at the pelvic brim and at the front of the third sacral vertebra respectively, are placed somewhat closely together. The loop is thus anatomicallj^ predisposed to axial rotation, and is the commonest seat of volvulus in the whole intestinal tract.
On the left and inferior aspect of the pelvic mesocolon near its base, a small peritoneal fossa {intersigmoid) is usually found in the angle formed by the root of the mesocolon and the parietal peritoneum. It occasionaUy contains an internal hernia which may become strangulated.
In advanced life, and in the chronically constipated, certain diverticula of mucous membrane are occasionally met with which project through the vascular gaps of the muscular coat into the bases of the appendices epiploicse in this region, and also between the layers of the pelvic mesocolon. They often contain foecal concretions and may become inflamed or even perforate, forming an abscess in the left ihac fossa, f
less acute angle and constitutes the narrowest part of the colon. It is a frequent site of stricture.
The kidneys. — These lie at the back of the abdominal cavity so deeply in the hypochondriac and epigastric region as to be beyond palpation in most individuals, unless enlarged or unduly mobile. The lower end of the right being slightly lower than its fellow, encroaches in health upon the lumbar and umbilical regions, and may be palpable on deep inspiration in spare subjects. These
organs lie much higher and nearer to the vertebrae than is usually supposed to be the case, the upper two-thirds of the right and all the left kidney being behind the ribs. Relatively to the vertebra3, the kidneys lie along the sides of the last thoracic and the first three lumbar.
To mark them in from the front the following points should be noted: The upper extremity of the right should reach as high up as the seventh costal cartilage, the left up to the sixth, on either side close to the costo-chondral and inter-cliondral junctions. This level will correspond to one half way between the sterno-xiphoid and transpyloric lines. The lower end.
Posterior layer of renal fascia
about 11 cm. (4| in.) below this point, would be opposite to the subcostal line; that of the right kidney is usually lower, and may encroach upon the umbilical line. For practical piu'poses the hilus is opposite a point on the anterior abdominal wall, a finger's breadth medial to the tip of the ninth costal cartilage (Stiles), or the junction of the transpyloric and lateral vertical lines. The importance of the relation of the last rib has been mentioned at p. 1245. The lateral vertical line has one-third of the kidney to its lateral side, and two-thirds to its medial side. The shortest distance between the two kidneys, obliquely placed so as to be closer above, 'at the upper part of their medial borders' (Thane and Godlee), measures about 6.2 cm. (2| in.). On the posterior surface of the body the ividney's boundaries are indicated by the following: — (1) A line parallel with, and 2.5 cm. (1 in.) from, the mid-line, between the lower edge of the tip
of the spinous process of the eleventh thoracic and the lower edge of the spinous process of the third lumbar vertebra; (2) and (3) lines drawn from the top and bottom of this line laterally, at right angles to it, for 7 cm. (2f in.); (4) a line parallel to the first, and connecting the extremities of (2) and (3). Within this parallelogram the kidney lies (Morris).
The chief relations of the kidneys are: — posteriorly — quadratus lumborum, psoas, diaphragm, last thoracic, ilio-hypogastric, and ilio-inguinal nerves. The twelfth rib lies behind both, the right, as a rule, not reaching above the upper border. The left often reaches the eleventh rib. The pleural reflection usually crosses the twelfth rib obliquely reaching below its neck. Anteriorly — The liver, right colic flexure and second part of the duodenum (figs. 956 and 1009), on
are shown in figs. 1110 and 1111.
The anterior and posterior layers are seen to be continuous above and laterally. Medially and below they remain separate and it is in this dii-ection that the abnormally movable kidney travels. The fatty tissue between the kidney and the renal fascia is known as the perinephric fat; that outside the fascia is the paranephi'ic fat.
the renal artery may take origin from the common iliac artery. An accessory renal artery running into the lower end of the kidney from the aorta may cause kinking of the ureter and is a not uncommon cause of hydronephrosis.
The suprarenal glands are not so firmly attached to the kidneys as to the diaphragm; hence they are not encountered in operations for movable kidney and are not removed in nephrectomy.
Brode] has shown that incisions into the kidney should be made rather behind its convex border (Brodel's bloodless line). Occasionally fusion of the lower poles occurs during development across the middle hue of the body, and a single horseshoe kidney results, with double ureter and vascular supply.
by the spermatic or ovarian vessels. It crosses the brim of the pelvis just in front of the bifurcation of the common iliac, and descends on the side wall of the pelvis in front of the hypogastric artery.
The abdominal part of the ureter may be exposed extraperitoneally by an extension forward of the usual lumbar renal incision. It is found lying between peritoneum and psoas 3.7 cm. (IJ in.) from the middle line and when the peritoneum is stripped from the posterior abdominal wall the ureter is invariably carried with it.
Aorta and iliac arteries. — The aorta enters the abdomen opposite the last thoracic vertebra, a point 12 to 15 cm. (5 to 6 in.) above the umbilicus, or rather above the mid-point between the infrasternal depression and the umbilicus (Thane and Godlee), and thence, lying to the left of the mid-line, divides into the two common iliacs opposite the disc between the third and fourth lumbar vertebrae, or opposite the body of the fourth lumbar vertebra. This point is about 2.5 cm. (1 in.) below and to the left of the umbilicus, and on a level with a line drawn across the highest part of the iliac crest. A line drawn from this point, with a slight curve laterally, to just medial to the centre of Poupart's ligament, will give the line of the iliac arteries; the upper third of this line giving the average length of the common iliac. The relation of the common iliac veins is shown in fig. 1112. The right, much shorter than its fellow, lies at first behind and then somewhat lateral to its artery. The left is at first to the medial side of its artery, and then behind the right. At the upper part of the fifth lumbar vertebra behind and lateral to the right artery, the vena cava begins.
The site of some of the branches of the aorta may be thus approximately remembered as follows: The cceliac artery is given off immediately after the aorta has perforated the diaphragm; directly below this is the superior mesenteric artery. About 2.5 cm. (1 in.) lower down, or 7.5 cm. (3 in.) above the umbilicus, the renal arteries are given off. About 2.5 cm. (1 in.) above the umbilicus would be the level of the inferior mesenteric artery. The relation of the above vessels to the transpyloric line (p. 1153) is as follows: (Stiles.) The cceliac artery is two fingers' breadth, the superior mesenteric one, above the line, the renal arteries are a finger's breadth below it. The origin of the inferior mesenteric is midway between the transpyloric and intertubercular lines.
canal.
Bony boundaries. — These are the same in either sex. Above and in front is the symphysis pubis, rounded off by the subpubic ligament; diverging downward and laterally from this point on either side are the rami of the pubes and ischia, ending at the tuberosities of the latter. In the middle line behind is the apex of the coccyx, and reaching from this to the tuberosities are the sacro-tuberous (great sacro-sciatic) ligaments, to be felt by deep pressure, with the lower border of the gluteus maximus overlapping them.
The depth of the perineum varies greatly — from 5 to 7. .5 cm. (2 to 3 in.) in the posterior and lateral part to 2.5 cm. (1 in.) or less in front. In the middle hne, extending longitudinally through the perineum, is the raphe, the guide to the urethra, and 'the line of safety' (on account of the small size of the vessels here) for operations on it.
Subdivisions. — An imaginary line drawn transversely across the perineum from one tuber ischii to its fellow divides the lozenge-shaped space into two triangles — (1) An anterior, or uro-genital; and 2) a posterior, or rectal. The pelvic floor includes an upper or pelvic diaphragm (formed by the levator ani and coccygeus on each side) and a lower incomplete uro-genital diaphragm (or trigone) .
The pelvic diaphragm (figs. 1113, 1114, 1115; see also figs. 397, 399, 400) isYmade up of the levator ani coccygeus muscles. It is somewhat funnelshaped. When viewed from above or below (fig. 395), its fibres are seen to form horseshoe-like loops, arising on either side anteriorly, and passing posteriorly backward around the uro-genital apertures to be inserted chiefly in the mid-line posteriorly. The pelvic diaphragm serves primarily for the support of the abdominal viscera. For a detailed description of these muscles, as well as those of the uro-genital diaphragm, see section on the Muscular System.
The xiro-genital diaphragm (or trigone) (fig. 400), the lower diaphragm of the pelvic floor, is both morphologically and functionally different from the upper. The uro-genital diaphragm is a sphincter muscular layer, derived (with the sphincter ani externus) from the primitive sphincter cloacae. The uro-genital diaphragm is composed of superior and inferior fascial layers, enclosing the membranous urethra, the sphincter urethrae membranacese and the transversus perinei profundus. Superficial to the uro-genital diaphragm is the superficial perineal interspace (fig. 400). This is covered by the superficial perineal (CoUes') fascia, and includes the crura and bulb of the corpora cavernosa, with associated muscles, vessels and nerves.
The space in the pelvic floor on each side below the pelvic diaphragm is the ischio-rectal fossa (figs. 399, 400, 1114). In the posterior or rectal triangle, where the urogenital diaphragm is absent, the ischio-rectal fossae form large wedge-shaped spaces. The lowei- wall or base is formed chiefly by the corresponding skin and superficial fascia, and partly by the external sphincter ani ; the medial wall by the
Falciform process
muscles (levator ani and coccygeus) and inferior fascia of the pelvic diaphragm; the lateral wall by the obturator internus muscle, with the corresponding obturator fascia (with Alcock's canal, incluchng the pudic vessels and nerves) . The apex of the fossa is above, where medial and lateral walls meet. The narrow fibrous roof strip joining the medial and lateral walls just above the level of the internal pudic vessels and nerves has been called the lamina terminalis (Elliot Smith, fig. 1114). Posteriorly the fossa is bounded by the gluteus maximus and lig. sacro-tuberosum. Anteriorly on each side the ischio-rectal fossae extend as narrow spaces between the pelvic diaphragm above, the uro-genital diaphragm below, and the pelvic wall laterally (figs. 400, 401, 402).
Contents. It is traversed by the inferior htemorrhoidal branches of the internal pudic artery, with the associated veins and nerves, passing to the external anal sphincter, the skin and the adjacent mucosa. The superficial vessels and nerves, as the)' run forward to pierce the superficial perineal fascia, lie in this space, as well as the inferior clunial (perforating cutaneous) branches and branches of the fom'th sacral nerve. The inferior
THE MALE PELVIS 1385
hemorrhoidal veins traverse the fossa obUquely from the lateral wall downward and medially. They are usually somewhat dilated near the anal orifice, and when morbidly enlarged constitute the condition known as htemorrhoids ("piles")- The inner opening of an ana! fistula caused by the bursting of an ischio-rectal abscess into the gut is usually within 2 cm. of the anal margin, between the internal and external sphincters.
The central point of the perineum is in the adult nearly an inch (2.5 cm.) in front of the anus, or midway between the centre of the anus and root of the scrotum. Here the following structures meet, viz., the levatores ani, the two transverse perineal muscles, the bulbo-cavernosus, and the sphincter ani.
The comparative weakness of the attachment of the sphincter ani in front, i. e., not into a bony point, is important in the division of it, as in operation for fistula. The sphincter should never be cut through anteriorly, especially in women, where its attachment here, blending with the sphincter vaginae, is a very weak one. This point also corresponds to the centre of the lower margin or base of the uro-genital diaphi'agm (triangular ligament). Its development varies much in different bodies. A little in front of this point is the bulb, with the corpus spongiosum passing forward from it. This would also be the level of the artery of the bulb, so that in lithotomy the incision should always begin below this point. A knife introduced at the central point, and carried backward and very sUghtly upward, shoiild enter the membranous urethra just in front of the prostate, e. g., iu median lithotomy and Cock's external urethrotomy. If pushed more deeply, it would enter the neck of the bladder.
In median lithotomy, an incision 3.7 cm. (I5 in.) long is made tlirough the central tendinous point and raphe, so as to hit the membranous urethra. The following structures are divided: — • Skin and fasciae; some of the most anterior fibres of the external sphincter ani; raphe and central tendinous point; minute branches of transverse perineal vessels and nerves; base of uro-genital diaphragm Ln centre; membranous m'ethra and constrictor urethras.
The attachments and arrangements of the superficial fascia (fig. 1115) must be traced and remembered. If the two layers of which it consists, the superficial alone extends over both urethral and rectal triangles alike, and is continuous with the similar structures in adjacent regions, the only difference being that, if traced foward into the scrotum and penis, it loses its fat, and contains dartos fibres. The deeper layer, found only over the urethral triangle, is called the fascia of CoUes (fig. 1115). Attached at the sides to the rami of the pubes, behind to the base of the uro-genital trigone or diaphragm, and open in front, it forms the superficial wall of a somewhat triangular pouch, limited behind by the uro-genital trigone, and containing the superficial vessels, nerves, and muscles, the bulb, adjacent part of the urethra, and crura of the penis. Owing to this space being closed behind and open in front, and to its containing the above structures, fluids extravasated within this space will obviously tend to make their way forward into the scrotum, penis, and lower part of the abdominal wall.
The uro-genital triangle is subdivided into two planes by the inferior fascia of the uro-genital diaphragm and fascia of Colles. The structures in the swperficial -plane, between the uro-genital diaphragm and the fascia of Colles, have been given above. Those in the deeper, i. e., between the two layers of fascia of the diaphragm, are — (1) The membranous urethra; (2) deep transverse perineal muscle and sphincter of the membranous urethra; (3) the bulbo-urethral (Cowper's) glands; (4) and (5) part of the pudic artery and nerve, and branches.
The scrotum. — The skin of the scrotum is thin and delicate so that when distended, as by a hydrocele in the tunica vaginalis, it is remarkably translucent. Attached to its deep aspect is a layer of involuntary muscle, the dartos. When the dartos is contracted, as under the influence of cold, the scrotal skin becomes rugose.
To this tendency to wrinkling, with consequent irritation from retained dirt, and the presence of many sweat glands the frequency of epithehoma in this part is due. The dartos is apt to cause inversion of the skin in wounds of the scrotum, but this difficulty in suturing may be counteracted by the application of a hot sponge, which relaxes the muscle.
The superficial fascia of the scrotum is continuous with the fascia of Colles and the superficial fascia of the penis. Hence extravasation of urine under the fascia of Colles's balloons the scrotum and penis. The laxity of the areolar tissue under the dartos accounts for the great swelling that occurs in cedema of this part.
The lymphatics of the scrotum, important by reason of the e.\ten.sion of scrotal cancer, drain into the superficial inguinal nodes. Those from the anterior aspect nearest the median raph6 run to the supero-lateral glands of this group, within a few cm. of the anterior superior spine.*
The numerous large sebaceous glands that are found in the skin of the scrotum may give rise to cysts or adenomata. The deeper layers of the scrotum are derived from the abdominal wall, being brought down by the processus vaginalis in the descent of the testis.
On palpation
the Smooth firm body of the testis, pressure on which causes the characteristic "testicular sensation" can be felt to lie in front of and rather medially to the epididymis. The three parts of the latter^ the caput above, the body, and the Cauda epididymidis below, can also be distinguished. Running upward from the
THE TESTIS 1387
back of the epididymis to the subcutaneous inguinal ring the spermatic cord can be felt. The bulk of the cord is made up of its coverings, of which the cremaster muscle is the most considerable, and of the pampiniform plexus of veins. On rolling the cord between the finger and thumb the ductus deferens can be felt like a piece of whipcord in the posterior part.
The ductus (vas) deferens is thickened and nodular in tuberculous epididymitis. In varicocele the dilated and elongated veins of the pampiniform plexus feel on palpation like a bag of worms in the scrotum. It is important that the student, before studying diseased conditions, should make himself familiar with the feel of the normal parts as mentioned above and be able to identify them.
Underneath the visceral layer of the tunica vaginalis, the body of the testis is covered by a dense fibrous layer, the tunica albuginea, which accounts for the small extent of swelling in orchitis as compared with epididymitis. The lymphatics of the testis run up in the spermatic cord through the inguinal canal, and accompanying the spermatic vessels end in the lumbar lymph nodes, below the level of the renal arteries. These nodes may be reached and removed along with the vessels by making an incision in the loin above the inguinal (Poupart's) ligament, and stripping the peritoneum off the posterior abdominal wall.
On the right side of the perineum (left side of this figure) CoUes's fascia has been turned back to show the superficial vessels. On the left side the superficial vessels have been cut away with the anterior layer of the uro-genital trigone to show the deep vessels.
The epididymis is the convoluted first part of the duct of the testis, about 6 m. (20 feet) in length. Its three portions are in differing connection with the testis. Thus the cauda is held in place by connective tissue, the body by the same medium; the caput by the vasa efferentia. Thus, when tubercular disease begins here, the testis itself is more likely to be early involved.
Ductus deferens. — -The two extremities and the course of this involve several practical points. About 4.5 cm. (18 in.) long, it begins, convoluted at first and with a distinct bend upward, in the cauda epididymidis. It thence passes almost vertically upward at the back of the testis and cord to the tubercle of the pubes. Entering the canal, it lies on the grooved upper aspect of the inguinal (Poupart's) ligament, and then under the arching fibres of the internal oblique and transversus, upon the transversalis fascia. Its position, characteristic feel, and yellowish aspect are' well-known guides in operations for varicocele and hernia, while it is always to be isolated and palpated when tubercular disease below is suspected. Leaving the canal by the abdominal inguinal ring, it hooks round the inferior epigastric artery and then descends into the pelvis over the external iliac vessels. Continuing its course downward and backward over the side of the pelvis, it arches backward over the side of the bladder, superficial to the obliterated hypogastric artery, and then deep to the ureter. The two ducts now help to form the lateral boundaries of the external trigone, between the base of the bladder and the rectum. They here become dilated and sacculated and then contract again to empty into the ejaculatory ducts.
The vesiculae seminales are diverticula growing out from the lower end of the deferential ducts at an acute angle, one on each side. They lie below and lateral to the deferential ducts and are related in front to the base of the bladder and posterior surface of the prostate, behind to the rectum, and above to the reoto-vesical pouch of peritoneum, which also descends to cover the upper part of their posterior aspect. The normal vesiculae seminales can scarcely be distinguished from the base of the bladder on rectal palpation, but when diseased, as in tuberculous or gonorrhoeal vesiculitis, are enlarged and indurated and can be detected readily.
The ejaculatory ducts, formed by the union of the vesicular and deferential duct of each side, are 2-2. .5 cm. in length. The first few millimeters of their course is extra-prostatic, and then entering the posterior surface of the prostate they run side by side downward and forward through the gland, close to the middle line, to open into the urethra on the colliculus seminalis at either side of the opening of the prostatic sinus. It is by these little ducts that infection travels from the urethra to the vesiculas and epididymis in gonorrhoea.
Descent of the testis. — -The testis is developed between the tenth and twelfth thoracic segments of the embryo, and subsequently moves downward. By the third month of intrauterine life it descends into the iliac fossa; from the fourth to the seventh month it hes at the abdominal inguinal ring; during the seventh month it passes obliquely through the abdominal wall by the inguinal canal; by the eighth month it lies at the subcutaneous inguinal ring, and it reaches the fundus of the scrotum about the time of birth. The left testis is slightty earlier than the right in all these stages. The descent referred to is due in part to the common descent of organs, associated with the descent of the diaphragm, but mainly to the gubernaculum. This is a mass of fibro-muscular tissue that forms under the inguinal fold (or plica gubernalrix) of peritoneum below the testis as it lies in the iliac fossa, and in the mesorchium. It grows down obliquely through the abdominal wall from a point lateral to the inferior epigastric artery, and tunnels out a passage for the testis. As it travels down into the scrotum it carries in front of it three layers of investing fascia derived from the abdominal wall, viz., e.xternal spermatic fascia from the external oblique, cremasteric from internal oblique and transversus muscles, and infundibuliform fascia from the transversalis fascia. The gubernaculum is attached above to the peritoneum and the posterior aspect of the testis, and by its subsequent contraction it draws down into the scrotum first a diverticulum of peritoneum, the processus vaginalis, and secondly the testis, which projects into the processus from behind just as it did into the coelom.
Shortly after birth, obliteration of the processus vaginalis should occur, commencing at the deep abdominal ring and immediately above the testis. The part of the processus between these two points disappears completely. The lowest part, surrounding the testis, persists as the tunica vaginalis. Failure of obliteration, if complete, leaves a congenital hernial sac; if
only the upper part perists, and does not communicate with the tunica vaginalis, it is called a funicular sac. Cysts originating in the processus vaginalis between the upper and lower points of primary occlusion are known as encysted hydrocele of the cord.
tTndescended testis. — It occasionally happens that descent of the testis fails on one or both sides, and in these cases the organ may remain, (1) in the iliac fossa, (2) in the inguinal canal, or (3) at the subcutaneous ring. Deprived of the protection normally afforded against injury bj^ the scrotum and tunica vaginalis, the misplaced testis is subject to trauma, shows a tendency to torsion of its pedicle owing to its long mesorohium, and sometimes becomes the seat of malignant disease. A funicular hernial sac is generally present. Such testes are atrophic and functionally deficient, and it is probably owing to their small size at an early stage that the gubernaculum fails to gain a hold on them. It has been shown by Bevan* that in undescended testis the ductus deferens is usually long enough to allow the organ to be placed in the bottom of the sci-otum by the surgeon without tension provided that the spermatic artery and pampiniform plexus of veins are divided. The blood-supply of the organ is then entirely derived frotn the deferential artery, a branch of the superior vesical. In rare cases the testis descends in a wrong direction (ectopia testis) and comes to he in the perineum, over Scarpa's triangle, or on the pubes.
Penis. — The subcutaneous tissue of the penis, as on the scrotum, is devoid of fat and the delicate skin is very mobile and distensible, hence the ballooning of these parts in extravasation of urine or cedema.
In radical amputation of the penis for malignant disease the whole organ, including the crura, is removed through an incision that splits the scrotum, and the stump of the corpus spongiosum (corpus cavernosum urethras) is brought out into the perineum behind the scrotum.
Congenital malformations of penis. — At an early stage of development the urethra opens on the inferior aspect of the penis behind the glans. After the ingi-owth of epithelium that forms the glandular urethi-a, this primitive meatus should close. Occasionally, however, it persists, and the glandular urethra is represented by a groove on the under aspect of the glans. In these cases of hypospadias the glans is flexed on the penis and the prepuce is deficient IdbIow and has a pecuhar "hooded" appearance. In epispadias the upper wall of the m-ethra and corresponding part of the corpora cavernosa are absent. This condition is usually present in cases of ectopia vesicas.
The male urethra is about 20 cm. (8 in.) in length, consisting of the cavernous portion, 16 cm, (6| in.), membranous 1 cm. (| in.) and prostatic 3 cm. (IJ in.). The narrowest part is the external orifice, and next to it the membranous urethra. The prostatic urethra is the widest and most dilatable. The bulbous urethra, just in front of the uro-genital diaphragm, is wider than the rest of the penile portion, but since it forms the most dependent spot in the fixed part of the urethra (from bladder to suspensory ligament of penis) , it is specially prone to gonorrhoeal stricture. Behind the bulb, the urethra narrows suddenly as it passes through the uro-genital diaphragm and contraction of the sphincters of
a catheter.
False passages most commonly occur through the floor of the bulb on account of this, difficulty in entering the membranous urethi-a. The point of a small catheter may also be caught in the following apertm'es: (1) The lacuna magna in the roof of the fossa navicularis of the glandular urethra; (2) other crypts or lacunae in the penile part, mostly situated in the upper wall; (3) the prostatic sinus in the floor of the prostatic urethra about its centre.
It is in the region of the uro-genital diaphragm that the urethra is most liable to be damaged by a fall or blow, and the urine extravasated as a result will be beneath CoUes's fascia. In rupture of the membranous urethra urine may find its way in front of the inferior fascia of the uro-genital diaphragm by coexisting injury to this, or tlirough openings in the vessels, etc.; in a few such cases urine will make its way backward behind the fascia into the space of Retzius, ascending thence between the peritoneum and transversahs fascia. The attachment of the deep layer of superficial fascia to the base of the m-o-genital diaphragm accounts for the fact that urine extravasated from a ruptured m'ethra or thi-ough an opening behind a stricture passes not backward into the anal triangle, but forward onto the scrotum and abdominal wall.
The prostate consists of a mass of racemose glandular tubules imbedded in a fibro-muscular stroma, that surrounds the first part of the urethra and lies below the neck of the bladder. Its base is intimately connected with the bladder by the continuation of vesical and urethral mucous membrane and by the insertion of the outer longitudinal muscular coat of the bladder into the gland. The inner circular muscle fibres of the bladder become specialised round the internal urethral orifice to form the internal sphincter.
The apex of the prostate hes at the level of the lower border of the pubic symphysis and 1.5 cm. behind it. It is firmly fixed to the superior fascia of the uro-genital diaphragm (deep layer of the uro-genital trigone) and here the urethra leaves it to become the membranous part. The anterior surface directed vertically lies 2 cm. behind the lower part of the pubic symphysis in relation to the prostatic plexus of veins; and from it the dense pubo-prostatic ligaments run forward on either side to the pubes. The posterior surface is in contact with the rectum, through the anterior wall of which it may be palpated 4 cm. (I5 in.) above the anal margin. It is separated from the rectum by the two layers of the recto-vesical septum (Elliot Smith).* The lateral surfaces are supported by the anterior fibres of the levator ani, from which, however, they are separated on each side by a dense mass of fibrous tissue in which the pudendal (prostatic) plexus of veins is imbedded.
The prostatic urethra traverses the gland nearer the anterior than the posterior surface, with a slight forward concavity. Its floor is placed posteriorly and presents an eminence, the colliculus seminalis, about the centre of which is the orifice of the prostatic sinus, on either side of which open the common ejaculatory ducts. The prostate is indefinitely divided into two lateral lobes. The fissure uniting them across the middle line in front of the urethra (the anterior commissure) is fibro-muscular and contains no glandular tissue. Behind the urethra the lateral lobes are continuous and the portion of gland Ijang between bladder, ejaculatory ducts and urethra has been erroneouslj^ termed the "middle lobe." Though not a separate lobe anatomically, adenomatous hypertrophy of this part is common, when it projects up into the bladder, and prevents the proper emptying of that organ.
Capsule and sheath of the prostate. — In senile enlargement of the prostate removal may be effected by the suprapubic or by the perineal route. In the former, the bladder is opened above the pubes, the mucous membrane lying over the gland as it projects into the bladder is scratched through behind, and with the finger the whole adenomatous mass is enucleated. This process usually involves tearing out the whole of the prostatic m-ethra, and the ejaculatory ducts. The parts left behind consist of (1) the "capsule" which is simply the outer part of the gland proper stretched over the adenomatous mass, and consists of fibro-muscular tissue with a few flattened glandular tubules (C. Wallace). f Outside this (2) the fibrous "sheath" is derived from the visceral layer of pelvic fascia, in which is imbedded, on the anterior and lateral aspects of the gland, the prostatic plexus. Since these veins are not torn there is com-
paratively little hfemorrhage. In the perineal operation the posterior surface of the gland is exposed by cutting through the perineum between the bulb and external sphincter ani, and dividing the attachment of the recto-m-ethi-al muscle to the m-o-genital diaphragm and its inferior fascia. This exposes the back of the recto-vesioal septum (aponeurosis of DenonvilKers) which is split at its base, opening up the reoto-prostatic space of Proust. By a longitudinal incision into the prostate on each side the adenomatous lateral lobes may be enucleated separately, and it is claimed without injury to the urethra or ejaeulatory ducts (Hugh Young).*
The bladder lies above the pubic symphysis at birth and so is mainly an abdominal organ. The anterior surface, in contact with the abdominal wall, has no peritoneal covering, but posteriorly the peritoneal reflection descends to cover the posterior surface of the prostate, which is relatively lower than in the adult.
The adult bladder when empty forms a pyriform contracted organ behind the symphysis, and bounding the retro-pubic space of Retzius posteriorly. Into this space urine is extravasated in extra-peritoneal rupture of the bladder, and may mount up behind the abdominal wall in the extra-peritoneal tissue. The space is closed below by the pubo-pro.stafic ligaments and prostatic plexus of veins. In distention, the neck of the bladder and prostate being relatively fixed and immovable, the free a-pex rises up into the abdomen. As it does so it raises the peritoneum off the abdominal wall, so that in moderate distention 5 cm. (2 in.) of abdominal wall above the pubes are free of peritoneum, and the bladder may be tapped here safely. The upper surface and a little of the posterior are covered by peritoneum, which is also related to the upper halves of the vesiculae seminales. Below the recto-vesioal pouch the base of the bladder presents a small triangular area in contact with rectum, bounded by the peritoneal cul-de-sac above, the converging deferential ducts on each side and the prostate below. Tlirough this triangle which is rather expanded in distention of the bladder, puncture per rechmi was formerly practised. The infero-lateral surfaces are slung up by the levator ani as by a hammock. The interior of the bladder can be examined by the cystoscope in the living patient. The mucous membrane is loose and ruQ;ose in contraction, except over the trigone at the base, the angles of which are formed by the ureteric orifices and the internal meatus. The mucosa here is firmly adherent to the muscular coat and smooth. In hypertrophy of the bladder-muscle from obstruction, a fasciculated appearance of the mucosa is seen and possibly diverticula between the bands of muscle.
Rectum and anal canal. — The rectum proper extends from the end of the pelvic colon, opposite the third sacral vertebra, to the upper end of the narrow anal canal, which runs downward and backward almost at right angles to the rectum and is 3-4 cm. in length. The commencement of the rectum lies 13-14 cm. (5-5| in.) above the anus in the adult. This point is marked internally by an infolding of the mucosa on the right and anterior wall and to some extent of the circular muscle fibres, due to the angle at which the free pelvic colon turns into the fixed rectum. This shelf of mucous membrane is known as the upper transverse fold (first valve of Houston).
Under normal conditions the rectum does not form a reservoir for faecal material, which is stored in the lower end of the pelvic colon, above the upper transverse fold, leaving the rectum empty except in defsecation. The rectum proper is subdivided into two compartments by the inferior transverse fold on the anterior wall (third or great valve of Houston), situated 8-9 cm. (3-3i in.) above the anus at the level of the anterior cul-de-sac of the peritoneum, and resulting from the adaptation of the rectum to the hollow of the sacrum. This can usually be made out on digital examination. The other transverse folds are inconstant and only present on great distention.
The rectum and anal canal may be divided into three regions: (1) peritoneal from the third sacral vertebra to the lower transverse fold and anterior reflexion of peritoneum onto bladder or vagina; (2) infraperitoneal (rectal ampulla) below this and above the levator ani; (3) anal canal, below the level of the levator ani, constriction b3r which marks it off from the ampulla and converts it into an antero-posterior slit.
The mucous membrane of the rectum proper is redundant and mobUe and of a bright pink colour as seen by the sigmoidoscope. It is dotted over by rectal pits, visible to the naked eye, containing lymphoid follicles, and by the smaller and more numerous Lieberkhiin's glands. In the peritoneal chamber the mucosa is transversely plicated. In the rectal ampulla it presents longitudinal folds in which lie branches of the superior hfemorrhoidal vessels. These longitudinal folds, known as the rectal columns, converge into the anal canal, and end at the level of the anal valves half way down the canal, each uniting two adjacent valves. The anal valves probably represent the original cloacal membrane, dividing the proctoda^um (formed from the epiblast) from the hypoblastic hindgut, and persistence of this membrane gives one form of imperforate anus (Wood Jonesf). The tearing down of a valve by hard faeces may be a cause of anal fissure, etc. (Ball). The mucous membrane of the anal canal is more firmly adherent
rectal ampulla is the first to be extruded.
Peritoneal relations. — The peritoneal chamber of the rectum has no covering of peritoneum behind, and the peritoneum, at first covering its first aspect and sides, leaves the sides obliquely and finally is reflected onto the base of the bladder (or the vaginal fornix in the female), at the level of the inferior rectal fold, 8 cm. from the anus.
Blood-supply. — (1) The superior hsemorrhoidal artery, a continuation of the inferior mesenteric, reaches the rectum behind, via the pelvic meso-colon and bifurcates at once. The two branches run round on either side below the peritoneal reflection; giving ofl^ secondary branches that pierce the muscular coat about the level of the inferior transverse fold, or anterior peritoneal reflection. Joining the submucous layer, these arteries run down in the rectal columns to the anal canal, where they anastomose with (2) the middle hsemorrhoidal arteries, branches of the hypogastric (internal iliac) and (3) the inferior hasmorrhoidal branches of the internal pudendal. The veins correspond. Their free anastomosis in the hsemorrhoidal plexus under the rectal columns, the union afforded here between the portal and systemic veins, the absence of valves in the superior hsemorrhoidal veins, and the constriction they are subject to in passing through the muscular coat, are some of the anatomical causes of the frequency of haemorrhoids.
The branches of the superior hremorrhoidal artery to the rectum anastomose but little with one another, as compared with the sigmoid arteries to the pelvic colon. The main trunk of the superior hsemorrhoidal usually receives a large anastomotic branch from the lowest sigmoid artery 1-2 cm. below the sacral promontory, upon which the upper part of the rectum is dependent for its blood-supply after ligature of the superior haemorrhoidal. Hence in high excision of the rectum it is important to place the ligature on the superior hsemorrhoidal above the sacral promontory if sloughing of the gut is to be avoided.* For lymphatics of the rectum see p. 735.
Supports of the rectum. — The anal canal is fixed by its attachment to the levator ani and perineal body. After division of the perineal body and recto-urethral muscle in front, the rectum is readily separable from -the back of the prostate and recto-vesical septum. When the levator ani has been divided on each side and the peritoneum opened, as in the perineal operation for excision of the rectum, the gut cannot be pulled down freely. The hand passed up behind it in the hollow of the sacrum meets on each side with a dense fibrous layer running from the sacrum opposite the third foramen onto the side of the rectum. This is the rectal stalk (Elliot Smith) and consists of dense fibrous tissue round the nervi erigentes from second, third and fourth sacral foramina and the middle haemorrhoidal vessels. It lies about 2.5 cm. above the levator ani, and after division of it the bowel is easily freed, so that the whole of the rectum and part of the pelvic colon may be drawn out at the perineum without tension.
Rectal examination. — The following points can be made out by the finger introduced into rectum: — (1) The thickened, roll-like feel of a contracted external sphincter; (2) the narrower, more expanded, internal sphincter extending upward for 2.5 cm. (1 in.) from this; (3) the rectal insertion of the levatores ani, which here narrows somewhat the lumen of the gut; (4) above the anal canal, with its contrasting capaciousness, is the more or less dilated rectum proper; (5) the condition of the ischiorectal fossse on either side; (6) the membranous urethra in front, especially if a staff has been introduced; the instrument now occupies the middle line, and has the normal amount of tissue between it and the finger, thus differing from one in a false passage (in a child an instrument is especially distinct); (7) just beyond the sphincters, or 3.7 cm. (1| in.) within the anus, lies the prostate; (8) converging toward the base of the prostate, and forming the sides of the triangular space, are the vesiculse seminales and ejaculatory ducts. These can rarely be felt unless diseased and enlarged; any enlargement of the sacculated ends of the deferential ducts is much more perceptible; (9) it is within this triangular space that the elasticity of a distended bladder can be felt. (10) Usually the lowest of the transverse folds (folds of Houston), semilunar in form and about 1.2 cm. (J in.) in width, can be made out (fig. 1116). (11) Behind, the coccyx and its degree of pliability and the lower part of the sacrum. It may also be possible to feel enlarged sacral nodes and a growth from the other pelvic bones.
The above examination refers chiefly to the male.^ It remains to refer to rectal examination in the female. Anteriorly, the soft perinseal body and recto-vaginal septum will be met with, and, through the latter, the cervix and os uteri, and, higher up, the lower part of the cervix uteri. More laterally the ovaries may be felt, but the uterine or Fallopian tubes, unless enlarged and thickened, are not to be made out. The student should be familiar with the feel of a healthy recto-uterine or recto-vesical pouch, according to the sex, and the coils of intestine which it may contain, so as to be able to contrast this with any collection of inflammatory or other fluid or mischief descending from the upper pelvis, e. g., from the vermiform appendix. Posteriorly, certain structures are met with in either sex. After a very short interval (sphincter and ano-ooccygeal body) the finger reaches the tip of the coccyx and explores the hollow of the sacrum. On each side are the ischial tuberosity and wall of the true pelvis. The finger hooked lateralward and upward, comes on the border of the falciform process of the sacrotuberous (great sacro-sciatic) ligament, passing between the above-mentioned bones.
FEMALE GENITAL ORGANS
The external organs will be considered first, followed by the internal. Under the external organs are included, for convenience sake, the labia majora and minora at the sides; and, in the middle line, from above downward — (1) The glans clitoridis with its prepuce; (2) the vestibule; (3) the urethral orifice; (4) the
importance in a clinical examination will be alluded to here.
The labia majora are two thick folds of skin, covered with hair on their outer surface, especially above, where they unite {anterior com7nissure) in the mons Veneris. They contain fat, vessels, and dartos, but become rapidly thinner below, where they are continuous at the front of the perineum (their posterior commissure).
When the above folds are drawn aside, the labia minora, or nymphae, appear, not projecting, in a healthy adult, beyond the labia majora. They are small folds of skin, which meet above in the prepuce of the clitoris, and below blend with the labia majora about their centre. Sometimes, especially in nulliparae, they unite posteriorly to form a slight fold, the fourchette.
The glans clitoridis, covered by its prepuce, occupies the middle line above. Below it comes the vestibule, a triangular smooth surface of mucous membrane, bounded above by the clitoris, below by the upper margin of the vaginal orifice, and laterally by the labia minora. In the middle line of the vestibule and toward its lower part, about 12 mm. (J in.) below the glans clitoridis, and 25 mm. (1 in.) above the fourchette, is the meatus or opening of the urethra (figs. 1034, 1037).
The vaginal orifice lies in the middle line between the base of the vestibule above, and the fossa navicularis below. Its orifice is partially closed in the virgin by a fold of mucous membrane, the hymen (fig. 1037). This is usually crescentic in shape attached below to the posterior margin of the vaginal orifice, and with a free edge towards the base of the vestibule. In some cases it is diaphragmatic i. e. attached all around, but perforated in the centre (fig. 1037).
The schrivelled remains of the hymen probably constitute the carunculse hymenales. On either side of the vaginal orifice, at it lower part, lie the racemose, muciparous, vestibular glands (glands of Bartholin), situated beneath the superficial perineal fascia and sphincter vaginae. Their ducts run slightly upward and open, external to the attachment of the hymen, within the labia minora. In relation to the upper two-thirds of the vaginal orifice, placed between the urogenital diaphragm behind and the sphincter vaginae in front, are the vascular bulbs of the vestibule, rupture of which produces pudendal hfematocele.
Fourchette and fossa navicularis. — The fourchette, as stated above, is the posterior commissure of the labia minora. Normally the inner aspect of this is in contact with the lower surface of the hymen. When the fourchette is pulled down by the finger, a shallow depression is seen, the fossa navicularis, with the fourchette for its posterior, and the hymen for its anterior, boundary.
considered first, followed by uterus and appendages, ovary and ureter.
Examination per vaginam. — The finger, introduced past the gluteal cleft, perineum, and fourchette, comes upon the elliptical orifice of the vagina, and notes how far it is patulous or narrow; the presence or otherwise of any spasm from the adjacent muscles; then, passing into the canal itself, the presence or absence of rugae, a naturally moist or a dry condition are observed. In the anterior wall the cord-like urethra can be rolled between the finger and the symphysis ; and further up than this, if a sound be passed, the posterior wall of the bladder. The anterior wall of the vagina is about 6.7 cm. (2| in.) long. The posterior wall, 7.5 cm. (3 in.) long, forms the recto-vaginal septum, and through it any faeces present in the bowel are easily felt. The cervix uteri is next felt for in the roof of the vagina, projecting downward and backward in a line drawn from the umbilicus to the coccyx. Besides its direction, its size, shape, mobility, and consistence should be noted. The os uteri should form a dimple or fissure in the centre of the cervix. Of its two lips, the posterior is the thicker and more fleshy feeling of the two. The vaginal culs-de-sac or fornices are next explored. These should be soft and elastic, giving an impression to the finger similar to that when it is introduced into the angles of the mouth. Any resistance felt here may be due to scars, swellings connected with the uterus (displacements or myomata), effusions of blood or inflammatory material, and, in the case of the lateral culs-de-sac, a displaced or enlarged ovary, or dilatations of the Fallopian tubes. The posterior cul-de-sac is much deeper than the anterior, and, owing to the peritoneum
descending upon the posterior wall of the vagina, when the finger is placed here it is only separated from the peritoneal sac by the vaginal wall and pelvic fascia. In examination of the pelvic organs the bimanual method, by which one hand on the hypogastric region, pushes them down and steadies them as well, is always to be employed to complete an examination.
The uterus and appendages. — The normal non-gravid uterus is usually anteflexed and anteverted so as to lie with its long axis approximately at right angles to that of the vagina. Its position varies considerably with the degree of distention of the bladder in front and of the rectum behind. The distance from external os to fundus, as estimated by the passage of a sound is in the adult virgin uterus 5.5 cm. of which 3 cm. belong to the cervix and 2.5 cm. to the body. In the empty multiparous uterus the total length of the cavity is 6 cm., 2.5 cm. comprising the neck and 3.5 cm. the body.
Peritoneal relations. — In front the peritoneum is reflected from the uterus to form the utero-vesical pouch at the level of the isthmus. Behind it covers not only the uterus but the posterior fornix of the vagina, before turning off onto the front of the rectum. Laterally the peritoneum leaves the uterus and passes on to the lateral pelvic wall as a large twofold partition fig. 1118), the broad ligament.
Base of ligament
The broad ligament, bearing in its upper border the uterine tube, in front the round ligament and behind the ovary, consists of (1) an upper thin part, the mesosalpinx lying above the attachment of the mesovarium, and containing the ovarian vessels and the epoophoron, and below this (2) the thicker mesometrium, between the layers of which is a dense mass of fibrous tissue surrounding the uterine artery.
The anterior aspect of the cervix below the utero-vesical pouch of peritoneum, is readily separable from the bladder with which it lies in contact, and the peritoneum may be raised oil the uterus with ease in the lower part of its attachment both front and back. Over the upper part of the body and fundus, however, the peritoneal covering is firmly adherent, and cannot be dissected off.
The ovary, attached by its hilum to the mesovarium, lies in a fossa at the back of the lateral wall of the pelvis just between the diverging external ihac and hypogastric vessels. To feel it the finger should be pushed well up in the side of the vagina toward the lateral wall of the pelvis. On the abdominal surface its position corresponds to the middle of a line drawn from the anterior superior ihac spine of that side to the opposite pubic tubercle (Rawlings).
Supports of the uterus. — The great mobility of the body of the uterus has been referred to above. The organ derives its support almost entu'ely from the attachments of the cervix and vaginal fornices. These rest on the pelvic floor, formed by the levator ani and perineal body which support them the more efficiently since the long axis of the vagina is at right angles to that of the uterus. Above the pelvic diaphragm the cervix is held up to the pelvic walls by strong specialised bands of fibro-muscular tissue running in both antero-posterior and transverse directions. The chief of these, lying in the base of the broad ligaments is a fibrous sheath sm-rounding the uterine artery as it descends medially from the hypogastric. In the anteroposterior direction the utero-vesical ligaments hold up the cervix to the pubes in front and the sacro-uterine ligaments bind it to the anterior aspect of the sacrum behiind. While firmly supporting the uterus these bands are elastic, and so do not fix it rigidly, but allow of the cervix being drawn downward by traction with vulsellum forceps.
For lymphatics of uterus and vagina see p. 745.
The ureter. — The pelvic portion of this duct is of special importance in operations on the uterus and upper vagina. It crosses the brim of the pelvis on either side at the biftu-cation of the common ihac artery, or just in front of it, and descends on the side waU in front of the hypogastric artery, crossing the obliterated umbilical 'and obturator arteries. Curving forward and medially it passes under the base of the broad ligament, where the uterine artery crosses above it, and so gains the lateral angle of the bladder by passing across in relation to the lateral fornix of the vagina. In the base of the broad ligament the ureter lies about 2 cm. (f in.) from the side of the cervix, and this relation must be borne in mind in excision of the uterus.
Pelvic floor. — The pelvic floor of the female corresponds in general to that of the male (see p. 1383). There are, however, important differences, due to the sexual organs. The urogenital diaphragm is relatively smaller in area, due to perforation by the vagina. The pelvic diaphragm is also correspondingly modified, and the pubo-coccygeus component is more strongly developed (see section on Musculature.) The ischio-rectal fossa is similar to that of the male (p. 1384).
PARTS CONCERNED IN INGUINAL HERNIA
In inguinal hernia, as in femoral and umbilical, there is a weak spot in the abdominal wall — one weakened for the needful passage of the testicle from within to outside the abdomen (p. 1387). The parts immediately concerned are the two inguinal rings, subcutaneous (external) and abdominal (internal), and the canal. Now, it must be remembered at the outset that the rings and canal are only potential — they do not exist as rings or canal save when opened up by a hernia, or when so made by the scalpel. The canal is merely an oblique slit or flat-sided passage. The subcutaneous and abdominal rings are so intimately blended with the structures that pass through them, and so filled by them, that they are potential rings only.
The subcutaneous inguinal (external abdominal) ring. — This is usually described as a ring : it is really only a separation or gap in the aponeurosis of the external oblique, by which in the male the testicle and cord, and in the female the round ligament by which the uterus is kept tilted a little foward, pass out from the abdomen. The size of this opening, the development and strength of its crura or pillars, the fascia closing the ring — all vary extremely. Formation : by divergence of two fasciculi of the external oblique aponeurosis. Boundaries : two crura — (1) Superior, the smaller, attached to the symphysis and blending with the suspensory ligament of the penis; (2) inferior, stronger, attached to the pubic tubercle and blending with the inguinal ligament, and so with the fascia lata. On this inferior, stronger crus rests the cord (and so the weight of the testicle) or round ligament. Shape : triangular or elliptical, with the base downward and medially toward the pubic crest.
Intercrural fibres (intercolumnar fascia) (external spermatic fascia). — This, derived from the lower part of the aponeurosis of the external oblique, ties the two crm'a together, and, being continued over the cord, prevents there being any ring here, unless made with a scalpel. This is the rule in the body: when any structure passes through an opening in a fibrous or muscular
INGUINAL HERNIA
layer, it carries with it a coating of tissue froro that layer; e. g., the inferior cava passing through its foramen in the diaphi-agm, and the membranous uretlu-a thi'ough the uro-genital diaphragm. Effect of position of the thigh on the ring.— As the lower crus is blended with Poupart's hgament, and as the fascia lata is connected with this, movements of the thigh will affect the rmg much, making it tighter or looser. Thus extension and abduction of the thigh stretch the crura and close the ring. In flexion and adduction of the thigh the crura are relaxed; and this is the position in which reduction of a hernia is attempted. In flexion and abduction of the thigh, the rmg is open; and this is the position in which a patient should sit, with thighs widely apart, to try on a tru.ss, and cough or strain downward, as in rowing. If the hernia is now kept up, the truss is satisfactory.
_ Helping to protect this most important spot, and preventing its being more than a potential rmg, are not only the two crura and the intercrural fibres, but also a structure which has been called a thu-d or posterior pillar, namely, the reflected inguinal ligament. This has its base above at the lower part of the linea alba, where it joins its fellow and the aponeurosis of the external oblique, and its apex downward and laterally, where, having passed behind the medial crus it blends with the lacunar (Gimbernat's) ligament. Again, the falx inguinalis (the con-
FiG. 1119. — The Parts concerned in Inguinal Hernia. (From a dissection in the Hunterian Museum.) External oblique, cut and turned back Internal oblique External oblique
Reflected inguinal ligament
joined tendon of the internal oblique and transversahs), curving mediaUy and downward to be attached to the ilio-pectmeal hne and spine, is a most powerful protection, behind, to what 13 otherwise a weak spot and a potential ring.
Inguinal canal.— This is not a canal in the usual sense, but a chink or flatsided passage m the thickness of the abdominal wall. The descriptions of the canal usually given apply rather to the diseased than to the healthy state. It was a canal once, and for a time only, i. e., in the later months of fcetal life (p. 1387). It remains weak for a long time after, but only a vestige of it remains in the wellmade adult.
Length.— In very early life there is no canal; one ring lies directly behind the other, so as to facilitate the easy passage of the testis. In the adult it measures about 37 mm. (l^ in.) in length, this lengthening being brought about by the growth and separation of the alse of the pelvis. This increased obliquity gives additional safety. On the other hand, a large hernia has not only opened \^^dely the canal and rings, but it has pulled them close together, and one behind the other thus not only rendering repair much more difficult, but also the path to the
(1) Floor. — This is best marked near the outlet, where the cord rests on the grooved upper margin of the inguinal (Poupart's) and the lacunar (Gimbernat's) lio-ament. The meeting of the transversalis fascia with this hgament forms the floor (2) i?oo/.— The apposition of the muscles and the arched border of the internal oblique and transversus. (3) Anterior wall— Skin, superficial fascia, external oblique for all the way. Internal oblique, i. e., that part arising from Poupart's ligament, for the lateral third or so. To a slight extent, the transversus and the cremaster. (4) Posterior wall.—For the whole extent, transversalis fascia, extraperitoneal tissue, and peritoneum. For the medial two-thirds, conjoined tendon of internal oblique and transversus, and the lateral edge of the reflected inguinal hgament, when developed.
Cremaster
The transversalis fascia is thicker and better marked at its attachments below; these arefa) laterally, to medial lip of iliac erest; (b) to the ingmnal ligament between the anteriorsuperior spine and the femoral vessels, where it joins the fascia ihaca; (c) opposite the femoral vessels it Tlso joins the fascia iliaca, and forms with it a funnel-shaped sheath; (d) mecbal to the femoral vessels the fascia transversalis is attached to the terminal (.^'l°-Pe«t>,^^f ) J^^^' ^^^J^f, the conjoined tendon, with which it blends. The falx ingmnahs {conjoined tendon) needs special reference It is foriied by the lower fibres of the internal oblique and transversus (arciform fibres) arching downward over the cord to be inserted into the crest and spme and the termmai aho-pectineal) line. The fibres of the internal oblique become increasingly tendmous as they descend, and this, with the fact that below they give off the cremaster, may «ause some difficulty in theh- identification when it is desked to unite them to the upper surface of Poupart s ligament in the operation of radical cure.
The abdominal inguinal (internal abdominal) ring.— It has already been said that the term 'ring' is here misapplied except in an artiflcial sense, as when an opening is made by a scalpel; or in abnormal conditions when a hernial sac is present. The abdominal ring is not a ring in the least, but merely a tunnelshaped expansion of the transversahs fascia, which the cord carries on with it as it escapes from the abdomen.
Site. — Midway between the anterior superior iliac spine and pubic tubercle. Shape : oval, with the long diameter vertical. Boundaries : centre of inguinal (Poupart's) ligament, about 12 mm. (| in.) below. Medially, the inferior epigastric artery (fig. 1121); the position of this vessel, by its pulsation, is an important guide to the insertion of the highest sutures between the arciform fibres and the inguinal ligament. Owing to the artery lying to the medial side, the incision, in cutting to relieve the deep constriction of an inguinal hernia, should always be made directly upward, so as to avoid the above vessel. A large oblique hernia may so have altered the relations of the parts, including the artery, that it is difficult to decide whether the hernia is oblique or direct. The above incision will be safe, because, iia either case, parallel to the vessel. Coverings. — There are two chief forms of inguinal hernia : — A. The cominon form: lateral, or oblique. — Lateral, because it appears (at the abdominal ring) lateral to the inferior epigastric artery. Oblique, because it traverses the whole of the inguinal canal, entering it at its inlet and leaving it at its outlet. This form is usually congenital in origin, and is due to non-obliteration of the processus vaginalis in infancy.
B. Rarer form : medial, or direct. — Medial, because it appears medial to the inferior epigastric artery. Direct, because, instead of making its way down the whole oblique canal, it comes by a short cut, as it were, only into the lower part of the canal, and then emerges by the same opening as the other.
B. Direct inguinal hernia. — This does not come through the abdominal ring, but,«making its waj' through the posterior wall of the lower third of the canal, either through the medial or intermediate inguinal fossa. Its coverings, therefore, vary slightly with its mode of exit (vide infra).
the posterior aspect of its so-called rings and canal, as these have to bear the early stress of a commencing hernia. It is against this aspect that a piece of omentum or intestine is constantly and insidiously pressing and endeavoui'ing to make its way out. Furthermore, when either of the above constituents of hernia have made their way a little farther, and got out into the abdominal ring or into the canal, the patient is no longer sound.
allantois, passes up between the apex of the bladder and the umbilicus.
(2) The obliterated hypogastric arteries. These, the remains of vessels which during foetal life carry the impure blood of the foetus out to the mother through the umbilicus, run up and join the urachus at the umbilicus.
In relation to these cords are the following fossae : — (a) A medial one, between the virachus and the obliterated hypogastric artery. This corresponds, on the anterior surface, to the subcutaneous inguinal (external abdominal) ring. Through this fossa comes the commonest form of direct inguinal hernia, (ft) Between the obliterated hypogastric artery and the inferior epigastric artery, which runs upward and medially to form the lateral boundary of Hesselbach's triangle, is an intermediate fossa. This is the smallest of all. The rarer form of direct hernia comes tlirough here, (c) The lateral fossa is lateral to the inferior epigastric artery. It is the most distinct of the three, from the way in which the cord or round ligament passes down within a glove-like vaginal process of the transversalis fascia. This fossa corresponds to the abdominal ring.
The coverings of a direct hernia may now be considered, together with the two-fold manner of exit of this hernia. It only traverses the lower part of the canal, making its way through either the medial or the intermediate inguinal pouch, (i) The commonest form, coming through the medial inguinal pouch, either pushes its way through or stretches before it the falx inguinalis. Its coverings are: — (1) Peritoneum; (2) extra-peritoneal fat; (3) transversalis fascia; (4) falx inguinalis (unless this is suddenly burst through); (5) (6) (7). At the subcutaneous ring the three coverings are the same as in the oblique variety, (ii) This rarer form of direct hernia comes through the intermediate inguinal pouch. As a rule, the falx inguinalis does not reach over this fossa. The coverings will be the same as in the last, with two exceptions — there is no falx inguinalis, and the cremasteric fascia, if well developed, will be present.
Varieties of inguinal hernia according to the condition of the vaginal process of peritoneum. — Inguinal herniEe have above been classified according to tlieir relation to the deep epigastric artery. It remains to allude to the arrangement of these same hernias according to the varying condition of the processus vaginalis. This pouch of peritoneum, which paves the way for the passage of the testis before this organ makes its start, eventually becomes the parietal layer (p. 1387) of the tunica vaginalis below, in this fashion: During the first few weeks after birth the process becomes obliterated at two spots — one near the abdominal ring, and one just above the testis. The obliterative process, commencing first above and descending, and then, ascending from below, the shrivelling continues until nothing is lett save the tunica vaginalis below. The following are possible hernial results of an imperfect obliteration of the process: —
make its way into the scrotum. The testis is now enveloped and concealed by the hernia.
(2) If the process is closed only above, i. e., near the abdominal ring, two varieties may be met with, the infantile and the infantile encysted. In the infantile, owing to pressure above, the weak septum gradually yields and forms a sac behind the unobliterated lower part of the processus funiculo-vaginalis. Thus three layers of peritoneum may now be met with in an operation, the two of the incompletely obliterated tunica vaginalis, and the proper sac of the hernia. In the encysted infantile variety the hernial pressure causes the septum to yield and form a sac projecting into, not behind, the incompletely obliterated tunica vaginalis. Here, theoretically, two layers of peritoneum will be met with. Another variety of such an encysted hernia may be produced by rupture, not stretching, of the above-mentioned septum.
(3) If the processus vaginalis be closed below and not above, a patent tubular process of peritoneum will lead down as far as the top of the testis. Any hernia into this process is called a hernia into the funicular process. All these varieties save the congenital and hernia into the funicular process are rare in practice. Other practical points are that all hernise in children and young adults are probably of congenital origin, and, therefore, the weakness is often bilateral, though it may not be so palpably. This applies to both sexes. Again in hernia of sudden origin into the funicular process with narrow surroundings, strangulation may be very acute.
Inguinal hernia in the female. — The inguinal canal in women is smaller and narrower than in men. Inguinal hernia is, therefore, less common in the female sex, and occurs in patients who happen to be tlie subjects of an unobliterated processus vaginalis, which extends for a varying distance along the round ligament, and is called the canal of Nuok. Inguinal hernia in the female is, therefore, always congenital. It is, practically, always of the oblique variety, and travels along the round ligament toward the labium majus. Its coverings will be the same as those of the oblique variety in the male, save that the cremaster, as a distinct muscle, is absent, and any fibres of the internal oblique which may be present are but little developed.
It is continuous through the scrotum with the deep layer of the superficial fascia of the perineum. Just below the inguinal hgament it is joined to the fascia lata. From these two facts it results that in rupture or giving way of the urethra the extravasated urine may come forward by way of the genitals (p. 13S5) and from the continuity of the fascia make its way on to the abdomen, but not down on to the thigh.
Between the two layers of superficial fascia lie the superficial nodes of the groin, the superficial branches of the common femoral artery, one or two cutaneous nerves, and some veins descending to the fossa ovahs to join the great saphenous vein.
(2) Inguinal (Poupart's) ligament. — This is also known as the crural arch, a misnomer, as 'crus' means leg. A description of its shape and attachments is given on p. 1371. Owing to the connection of the fascia lata to its lower border, the fossa ovalis (saphenous opening), which is situated in the fascia lata, and has its upper cornu blending with the inguinal ligament, will be affected by movements of the thigh, much as is the subcutaneous inguinal (external abdominal) ring, being tightened and stretched when the limb is extended and abducted, relaxed when it is adducted and flexed.
The different structures are arranged in three compartments (fig. 1122), named latero-medially : — A. lateral, iliac, or muscular; B. central, or vascular; and C. medial, or pectineal. Of these, the first is the largest; the second or intermediate one lies slightly nearer to the inguinal ligament than the other two ; while the medial compartment differs from the other two by not communicating with the pelvis, being closed above {vide infra).
(A) The lateral, or iliac, compartment is bounded in front by the inguinal ligament and the iliac fascia, which is here blending with it, behind by the ihum, laterally by this bone and the sartorius, and medially by the ilio-pectineal septum, which, descending from the blending of , the iliac fascia and the inguinal ligament above, passes down to the iUo-pectineal eminence, and thence to the medial aspect of the front of the capsule of the hip-joint. This compartment transmits the ilio-psoas and femoral (anterior crural) and lateral cutaneous nerves. (B) The vascular compartment is bounded, in front, by the inguinal ligament and the transversahs fascia, which here blends with it, forming the so-called deep crui'al arch, and at the same time
descends on to the front of the femoral sheath. The posterior boundary, Cooper's ligament, is formed by the meeting of the ilio-pectineal septum laterally and the pectineal fascia or sheath — medially the lacunar (Gimbernat's) ligament, and laterally the ilio-pectineal septum. This intermediate compartment transmits the ex ernal iliac vessels and the lumbo-inguinal nerve. This lies to the lateral side of the artery, the vein medially. Between the vein and the base of the lacunar ligament is the femoral canal (vide infra). (C) The medial or pectineal compartment is bounded by the pectineal fascia, continuous with the pubic part of the fascia lata, and behind by the pubic ramus. It lodges the upper end of the pectineus muscle, and the handle of a scalpel passed upward along the muscle would be prevented from passing into the pelvis by the lacunar ligament and the blending of the pectineal fascia with the upper border of the pubic ramus.
(3) Lacunar (Gimbernat's) ligament. — This is merely tlie triangular medial attachment of Poupart's ligament. Its apex is attached to the pubic tubercle; of its three borders, the base is free toward the vein and the femoral canal. Its upper border is continuous with Poupart's ligament; its lower is attached to the terminal (ilio-pectineal) line.
(4) Fascia lata. — Two portions are described over the upper part of the thigh : ■ — (a) An iliac, lateral and stronger, attached to the inguinal ligament in its whole extent and lying over the sartorius, ilio-psoas, and rectus. (6) A pubic, medial, weaker, and much less well defined, is attached above to the terminal line and the tubercle of the pubes. The upper cornu of the fossa ovalis is at the lacunar ligament, and at the lower cornu the two portions of the fascia blend.
Their relation to the femoral vessels. — The iliac portion, being attached along Poupart's ligament, passes over these. The pubic portion, fastened down over the pectineus, which slopes down on to a deeper plane than the adjacent muscles, passes behind the femoral vessels to end on the capsule of the hip-joint.
(5) Fossa ovaUs (saphenous opening). — This is not an opening, but an oval depression, situated at the spot where the two parts of the fascia lata diverge on different levels. Though the fascia lata is wanting here, there is no real opening, as the deficiency is made up by the deep layer of superficial fascia, or cribriform fascia, which fills up the opening.
Uses of the fossa ovalis {saphenous opening). — Though a weak spot, it is so on purpose to transmit the saphenous to the femoral vein, and the superficial to the deep lymphatics. The depression is present in order to allow the saphenous vein to be protected from pressure in flexion of the thigh.
lateral to the tubercle of the pubis.
Diameters. — Vertically, 2.5 cm. (1 in.), by 1.2 or 1.8 cm. (| or f in.). Shape: oval, with its long axis downward and laterally. Two exlremities or cornua: upper blending with the lacunar ligament; lower, where the two parts of the fascia lata meet. Two borders: lateral or falciform, also known as the ligament of Hey, or femoral ligament. Semilunar in shape, arching downward and laterally from the lacunar ligament to the inferior cornu. This lies over the femoral vessels, and is adherent to thezn; to it is fixed superficially the cribriform fascia {vide infra). The medial border is much less prominent, owing to the weakness of the pubic part of the fascia lata which forms it.
(6) Femoral sheath. — This is a funnel-shaped sheath, carried out by the femoral vessels under Poupart's ligament, and continuous above (in front) with the transversalis fascia as it descends to the ligament, lining the inner surface of the abdominal wall; and (behind) with the iliac fascia, and below continuous with the proper sheath of the femoral vessels.
It is not only funnel-shaped, but large and loose, for two reasons: — {a) That there be plenty of room for the femoral vein and the slowly moving venous current in it to ascend without compression; (b) to allow all the movements of the thigh taking place — flexion and extension — without undue stretching of the vessels. By two connective-tissue septa the sheath is divided into three compartments — the lateral for the artery, the intermediate for the vein, and the medial one for the femoral canal {vide infra). Thus one septum lies between the artery and vein, and another between the vein and the femoral canal.
(7) Femoral canal. — Definition: the medial division of the femoral sheath. The fascia transversalis and fascia iliaca meet directly on the lateral side of the femoral artery, but not so closely on the medial side of the femoral vein. Hence a space exists here, perhaps to prevent the thin-walled vein, with its sluggish current, being pressed upon, but it is merely a slight gap — not a canal, unless so made by a knife or by the dilating influence of a hernia.
(8) Femoral ring. — This is mainly an artificial product. It is the upper or abdominal opening of the femoral canal. Shape: oval, with its long axis transverse. It is larger in women. Boundaries: medially, the lacunar ligament; laterally, the femoral vein; in front, the inguinal ligament and the thickening of the transversahs fascia attached to it, and called 'the deep crural arch'; behind the pectineus and Cooper's ligament, a thickened fascial bundle attached
Lymphatic node in femoral ring
The obturator artery, given off from the external iliac with the inferior epigastric, descends to gain the obturator foramen, but at a safe distance from the
strictioii
to the hnea terminalis (fig. 1122). It is closed by the septum crurale, which is a barrier of fatty connective tissue, continuous with the extra-peritoneal fatty layer, perforated by lymphatics passing upward to the pelvic nodes.
Position of vessels around the ring. — Laterally the femoral vein; above, the epigastric vessels as they ascend from the external iliac vessels, pass close to the upper and lateral aspect of the ring; immediately in front are the cord and spermatic vessels always to be remembered in this hernia in the male; toward the medial side there may be an unimportant anastomosis between the epigastric artery above and the obturator below.
If from dilatation of the above anastomosis the obturator artery comes off abnormally from the inferior epigastric, it will descend, and usually does so, close to the junction of the external iliac and common femoral vein, and thus to the lateral and so the safe, side of the ring (fig. 1123, A). In a very few cases it curves more mediallj', close to the lacunar ligament, and thus to the medial side of the ring, and is then in great danger (fig. 1123, B). In two out of
Course of femoral hernia. — At first this is downward in the femoral canal. A pouch of peritoneum having been gradually, after repeated straining, coughing, etc., pushed through the weak spot, the femoral ring, further weakened perhaps, together with all the parts in the femoral arch, by child-bearing, some extra effort will force intestine or omentum into this pouch and thus form a hernia. Thus formed, femoral hernia passes at first downward in the femoral canal as far as the fossa ovaUs, but, as a rule, does not go farther downward on the thigh, but mounts forward and upward, and somewhat laterally, even reaching the level of the inguinal ligament. The reasons for this change of position are: — (1) The narrowing of the femoral sheath, funnellike, i. e., wide above, but narrowed below; (2) the unyielding nature of the lower margin of the fossa ovalis; (3) the fact that this margin and the lateral border are united to the femoral sheath; (4) the constant flexion of the thigh; (.5) the fact that vessels (cliiefly veins) and lymphatics descend to the fossa ovaUs, the veins to join the saphenous vein and the lymphatics to join the deeper group; these descending vessels serve to loop upward or suspend a femoral hernia, and thus prevent its further course downward.
and superficial fascia are added.
Some of these may be deficient by the hernia bursting through them, or they may be matted together. Sir A. Cooper thought this especially likely to occur with the layer of femoral sheath and septum crurale, to which he gave the name oi fascia propria.
The relations of an inguinal and femoral hernia respectively to the pubic tubercle are of importance in distinguishing between them clinically. If a finger is placed on the pubic tubercle a hernia that lies above and medial to it will be inguinal, one below and lateral to it wiU be femoral.
Radical cure of femoral hernia. — The close proximity of the femoral vein always introduces difficulty in the introduction of the deep sutures for closure of the crural ring. Any closure below this point is certain to be inefiicient. The safest and simplest method is to feel for the pulsation of the femoral artery, and make allowance for the vein on its medial side. The latter vessel is then protected by the finger-tip passed up the femoral canal, so that its dorsum rests against the vein and its tip upon the linea terminalis. The sutures are then passed so as to pick up the ilio-peotineal fascia and its thickened part. Cooper's ligament, below, and the deep crural arch and Poupart's ligament above (fig. 1122). Thus, when tightened, they draw the anterior and posterior boundaries of the ring together. (Lockwood, Bassini.)
A hernial protrusion at the umbilicus, or exomphalos, may occur at three distinct periods of life, according to the anatomy of the part. Any account of umbilical hernia would be incomplete without an attempt to explain how this region, originally a most distinct opening, is gradually closed and changed into a knotty mass of scar, the strongest point in the abdominal wall.
During the first weeks of foetal life, in addition to the urachus, umbilical arteries, and vein, some of the mesentery and a loop of the intestine pass through the opening to occupy a portion of the body cavity situated in the umbilical cord, later on returning to the abdominal cavity. Occasionally this condition persists, owing to failure of development, and the child is born with a large hernial swelling outside the abdomen, imperfectly covered ^vith skin and peritoneum. To tlais condition the term congenital umbilical hernia should be applied.
Later on in foetal life it is the umbilical vessels alone which pass through this opening. At birth there is a distinct ring, which can be felt for some time after in the flaccid walls of an infant's belly. If this condition persist, a piece of intestine may find its way through, forming the condition which should be known as infantile umbilical hernia.
This condition is not uncommon. Why it is not more frequently met with is explained by the way in which this ring of infancy is closed and gradually converted into the dense mass of scar tissue so familiar in adult life. This is brought about — (1) by changes in the ring itself; (2) by changes in the vessels which pass through it.
THE BACK 1403
posterior aspect of the belly wall. In older infants these fibres lose their elasticity, become more tendinous, and then shrink more and more. As they contract they divide, as by a ligature, the vessels passing through the ring, thus accounting for the fact that the cord, wherever divided, drops off at the same spot and without bleeding.
(2) Changes in the vessels themselves. — When blood ceases to traverse these, their lumen contains clots, their muscular tissue wastes, while the connective tissue of their outer coat hypertrophies and thickens. Thus, the umbilical vessels and the umbilical ring are, alike, converted into scar tissue, which blends together. This remains weak for some time, and may be distended by a hernia (infantile).
Finally, we have to consider the state of the umbilicus in adult life. The very dense, unyielding, fibrous knot shows two sets of fibres: — (1) Those decussating in the middle line; and (2) two sets of circular fibrous bundles which interlace at the lateral boundaries of the ring. The lower part of the ring is stronger than the upper. In other words, umbilical hernia of adult life, when it comes through the ring itself and not at the side, always comes through the upper part. In the lower three-fourths of the umbilicus the umbihcal arteries and urachus are firmly closed by matting in a firm knot of scar tissue; in the upper there is only the umbilical vein and weaker scar. To the lower part run up the umbilical arteries and the urachus. Owing to the rapid growth of the abdominal wall and pelvis before puberty, and the fact that the urachus and the umbilical arteries, being of soar tissue, elongate with difficulty, the latter parts depress the umbilicus by reason of their intimate connection with its lower half.
Owing to the usual exit of an umbilical hernia of adult life being through the upper part of the ring, the constricting edge in strangulation should be sought below and divided downward. As pointed out by Mr. Wood, it is here that the dragging weight of the hernial contents and the weight of the dress tend to produce the chief results of strangulation. An incision here also gives better drainage if required.
Coverings of an umbilical hernia. — These, more or less matted together, are : — (1) Skin; (2) superficial fascia, which loses its fat over the hernia; (3) prolongation of scar tissue of the umbilicus gradually stretched out; (4) transversalis fascia; (5) extra-peritoneal fatty tissue; (6) peritoneum. If the hernia come through above the umbilicus, or just to one side, the coverings will be much the same; but, instead of the layer from the umbilical scar, there will be one from the linea alba.
Strangulated umbilical hernia of adult life. — In this, the most fatal of the strangulated hernise ordinarily met with, the following are practical points in the surgical anatomy: — 1. The coverings, including the sac, are always thin, at times so markedly so that the intra-peritoneal contents are practically subcutaneous. 2. The sac is multilocular, and one or more of its chambers may he very deep. 3. The contents are numerous, viz., omentum, often voluminous and adherent, transverse colon, and later in the history, small intestine. 4. The contents are often adherent to the sac and each other, thus explaining the irreduoibility. 5. The long duration of the presence of the transverse colon with its stouter walls accounts for the period, often prolonged, in which warning evidence of incarceration precedes that of strangulation. 6. The communication with the peritoneal sac is direct, short, and during a prolonged operation, free. Infection is thus readily brought about.
by the relations of skeleton, muscles, viscera and nervous system.
Median furrow. — This is more or less marked according to the muscular development, lying between the trapezii and semispinales capitis, in the cervical region, and the sacro-spinales lower down. The lower end of the furrow corresponds to the interval between the spines of the last lumbar and the first sacral vertebra. (Holden.)
Vertebral spines. — Those of the upper cervical region are scarcely to be made out even by deep pressure. That of the axis may be detected in a thin subject. Over the spines of the middle three cervical vertebrae is normally a hollow, owing to these spines receding from the surface to allow of free extension of the neck. The seventh cervical is prominent, as its name denotes. Between the skull and atlas, or between the atlas and epistropheus, a pointed instrument might penetrate, especially in flexion of the neck.
Of the thoracic spines, the first is the most prominent, more marked than that of the last cervical; the tliird should iDe noted as on a level with the medial end of the scapular spine, and in some cases with the bifurcation of the trachea; that of the seventh with the lower angle of the scapula; that of the twelfth with the lowest part of the trapezius and the head of the twelfth rib. The obliquity and overlapping_ of the thoracic spines are to be remembered.
Of the lumbar spines, the most important are the second, which corresponds to the termination of the cord, and the fourth, which marks the highest part of the iliac crests and the bifurcation of the abdominal aorta. The lumbar spines project horizontally, and correspond with the vertebral bodies. The third is a little above the umbilicus.
Owing to the obliquity of the thoracic spines, most of them do not tally with the heads of the correspondino; ribs. Thus, the spine of the second corresponds with the head of the third rib ; the spine of the third with the head of the fourth rib ; and so on till we come to the eleventh and twelfth vertebrae, which do tally with then* corresponding ribs. (Holden.)
considerable percentage the last rib is so abnormally short that it does not reach as far as the lateral border of the sacro-spinalis; or is so rudimentary as to resemble a transverse process (consequently the only safe method of counting ribs is from above). In these cases the lower end of the pleura maj^ pass from the lower part of the twelfth thoracic vertebra, almost horizontally to the lower edge of the eleventh, rib.
Muscles. — The student will remember the greater number and complexity and the numerous tendons of the muscles which run up on either side of the spines; the firmness and inextensibility of their sheaths; the large amount of cellular tissue between them; and the fact that toward the nape of the neclc these muscles lie exposed instead of being protected in gutters, as is the case below: all these anatomical points explain the extreme painfulness and obstinacy of sprains here.
Trapezius. — To map out this muscle, the arm should be raised to a right angle with the trunk. The external occipital protuberance should be dotted in, and the superior nuchal line passing out from this; below, the twelfth thoracic spine should be marked; and laterally, the lateral third of the clavicle and the commencement of the scapular spine. Then a line should be drawn from the protuberance vertically downward to the twelfth thoracic spine; a second from about the middle of the superior nuchal line to the posterior and lateral third of the clavicle; and a third from the last thoracic spine upward and laterally to the root of the spine of the scapula.
Cfficum and vermiform process
Latissimus dorsi. — The arm being raised above a right angle, the spines of the sLxth thoracic and the third sacral vertebra should be marked; then the outer Up of the crest of the Uium, the lower two or three ribs, the lower angle of the scapula, and the posterior fold of the axiUa, and finally the intertubercular (bicipital) gi-oove should all be marked.
A vertical line from the sixth thoracic to the thu-d sacral spine will give the spinal origin of the muscle. Another from the thu-d sacral spine to a point on the iliac crest, 2.5 cm. (1 in.) or more lateral to the edge of the sacro-spinalis, will give the origin of the muscle from the sheath of the sacro-spinalis and the ilium. A line from the sixth thoracic spine, almost transversely at first, with increasing slight obliquity over the inferior angle of the scapula to the axilla and intertubercular groove, will mark the upper border of the muscle. Another very oblique line from the point of the iliac crest upward and laterally to the axilla will give the lower border and the tapering triangular apex of the insertion. The muscle may be attached to the angle of the scaptila, or separated from it by a bursa.
Triangle of Petit. — This small space lies above the crest of the ihum, at about its centre, bounded by the anterior edge of the latissimus behind and the posterior border of the external obhque, in front. Through this gap, when the muscles are weak, a lumbar abscess occasionally, and very rarely, a lumbar hernia, may appear.
Origin of spinal nerves. — It is very important to remember the relations of these to the vertebral spines, in determining the results of disease or injury of the cord and the parts thereby affected. The above relations may be given briefly as follows: —
occiput and the sixth cervical spine. The upper six thoracic come off between
Fig. 1126. — Chief Arterial Anastomoses on the Scapula. (From a dissection in the Hunterian Museum.) Supra-spinatus Transverse scapular artery
Circumflex scapular artery Posterior circumflex artery
the above spine and that of the fifth thoracic vertebra. The origins of the lower six thoracic nerves correspond to the interval between the fourth and the tenth thoracic spines. The five lumbar arise opposite the eleventh and twelfth thoracic spines; and the origins of the five sacral correspond to the first lumbar spines. The diagram and table (fig. 1124), arranged by Dr. Gowers from anatomical and pathological data, show the relations of the origins of the nerves to their exits from the vertebral canal, and the regions supplied by each.
Scapula, its muscles and arterial anastomoses. — Amongst the landmarks in the back, the student should be careful to trace the angles and borders of the scapula as far as these are accessible. The upper border is the one most thickly covered. With the hands hanging down, the upper (medial) angle corresponds to the upper border of the second rib; the lower angle to the seventh intercostal space; and the root of the spine of the scapula to the interval between the third and fourth thoracic spines.
The axillary border of the scapula, covered by the latissimus dorsi and teres major, may best be palpated with the arm hanging to the side. The vertebral border is brought into prominence by placing the hand on the opposite shoulder. This border is held in apposition with the thorax by the serratus anterior; consequently in paralysis of that muscle, supplied by the long thoracic nerve (5, 6, and 7 C), it becomes unduly prominent, giving rise to "winged scapula." Fig. 1126 shows the chief arteries around the scapula. The anastomoses on the acromial process between the transverse scapular (supra-scapular) thoraoo-acromial, and circumflex humeral arteries are not shown. The numerous points of ossification, primary and secondary, by which this bone is developed explain, in part, the frequency of cartilaginous and other growths here.
The anatomy of the loin behind, the ilio-costal region, is of prime importance, owing to the numerous operations here. The lateral border of the sacro-spinalis and quadratus lumborum may be indicated on the surface thus. (Stiles.) That of the sacro-spinalis by drawing a line from a point on the Oiac crest 8.2 cm. (Sj in.) (four fingers'-breadth) from the middle line upward and slightly laterally to the angles of the ribs. That of the quadratus passing upward and sUghtly medially Ues a little lateral to that of the sacro-spinahs (erector) at the crest,
and a little medial to it at the twelfth rib. The ascending and descending colon lie in the slightly depressed angle between the two muscles. The iho-costal region varies greatly in space according to the length of the lower ribs, shape of the chest, and development of the ihac crest. An incision here — that for exploration of the kidney may be taken as the type — would be an oblique one, about 10 cm. (4 in.) long, starting in the angle'between the twelfth rib and the sacro-spinahs muscle and passing forward and downward toward the anterior extremity of the iliac crest. In its upper part the incision should lie 1.2 cm. (J in.) below the tweltfh rib. The anterior fibres of the latissimus dorsi are divided behind, the posterior ones of the external oblique in front. The yellowish-white lumbar fascia now comes into view, and is the first important landmark. It and the fibres of the internal oblique and transversus which arise from it are next carefully divided. The last thoracic nerve and lowest intercostal artery may also require division. If the latter is cut close to the rib, the htemorrhage is troublesome. The transversalis fascia remains to be divided. To avoid the peritoneum, the deeper part of the
incisions should always be made from behind forward. If more room is required, as in large growths or in exploration of the ureter, the incision must be prolonged beyond the iliac crest, the lumbo-ilio-inguinal incision of Morris.
The commencement of the trachea and oesophagus has been given in front as corresponding to the sixth cervical vertebra. If examined from behind, this point, o-sving to the obliquity of the spines, would be a httle lower down. The trachea, about 12.5 cm. (5 in.) long, descending in the middle line, bifurcates opposite to the interval between the third and fourth thoracic spines (or fourth and fifth bodies). The bronchi enter the lungs at about the level of the fifth thoracic spine, the right being the shorter, wider, and more horizontal. The root of the lung is opposite to the fourth, fifth, and sixth dorsal spines, midway between these and the vertebral border of the scapula. The structures in it are the bronchus, pulmonary artery, two pulmonary veins, bronchial vessels, lymphatics, and nerves. The phrenic nerve is in front, the posterior pulmonary plexus behind. On the right side the superior vena cava is in front, the vena azygos (major) arching over the root at the level of the fourth thoracic vertebra. On the left side the aorta arches over the root, and the thoracic aorta descends behind it. The oesophagus, about 25 cm. (10 in.) in length, starting in the middle line, curves twice to the left, at first gradually at the root of the neck; from this point it tends to regain the middle line up to the fifth thoracic vertebra; thence finally turns again, and more markedly to the left, and passes through the diaphragm opposite to the tenth, entering the stomach here or at the eleventh thoracic vertebra (ninth or tenth thoracic spine). In the thorax this tube traverses first the superior, then the posterior, mediastinum. At three spots, i. e., its commencement, where it is crossed by the left bronchus, and at the cardiac orifice, it presents narrowings. The relations of this tube to the pleura, pericardium, aorta, vagi, and thoracic duct are important in the ulceration of malignant disease and infected bodies, and in the passage of instruments.
The aorta reaches the left side of the vertebral column, with its arch just above the fourth thoracic spine, and thence descends on the front of the column, with a shght tendency to the left, to bifurcate opposite the fourth lumbar spine.
The spinal cord. — This, about 45 cm. (18 in.) long, extends from the foramen magnum to the junction between the first and second lumbar vertebrae. Up to the third month of foetal life it reaches to the sacral end of the vertebral canal ; later, owing to the more rapid growth of the bony wall, its lower limit is at birth opposite the third lumbar vertebra. The dura mater is continued, as a sheath, as low as the second sacral vertebra. It is anchored above to the upper cervical vertebrae and the foramen magnum, and below, as the filum terminale, to the periosteum of the coccyx. The deficiency of the spinous processes and laminae of the fourth and fifth pieces of the sacrum allows of infection, e. g., of a bed-sore reaching the membranes, and so the cord. The arachnoid and pia of the cord are continuous above with those of the brain.
The parts of the column most exposed to injury are the thoraco-lumbar and cervico-thoraoic partly because here more mobile parts are joined to those which are more fixed, and also from the amount of leverage exerted on the thoraco-lumbar region, and, in the case of the upper region, because this is affected by violence exerted on the head. The chief provisions for protection of the cord are the number of bones and joints which allow of movement without serious weakening, the thi'ee om-ves and columns, cervical, thoracic, and lumbar, ensuring bending before breaking; the large amount of cancellous tissue and the number and structure of the intervertebral discs all tending to damp vibrations; the large size of the theca vertebrahs and the way in which the cord, anchored and slung by the thirty-one pairs of nerves and the Ugamenta denticulata, about twenty in number, occupies neutral ground in the centre of the canal as regards injury directly and indirectly applied.
A line drawn joining the highest points of the iliac crests crosses the fourth lumbar spine. The needle is inserted in the median line between the third and fom-th or the fourth and fifth spines, and directed forward and slightly upward. The back must be flexed as fully as possible in order to widen the interspinous spaces. The needle is passed to a depth of about 5 cm. (2 in.) in an adult, or 1.8 cm. (f in.) in an infant. In the supine position the lowest part of the subarachnoid space ia in the mid-thoracic region, and an anaesthetic fluid, non-diffusible and of a
bifurcation of the common carotid.
Sixth. Cricoid cartilage. Ending of pharynx and larynx. Consisting of the fused fifth and sixth ganglia, the middle cervical ganglion is usually opposite this vertebra. Here the omo-hyoid crosses the common carotid, and at this spot, the seat of election, the centre of the incision for tying this vessel is placed. At this level the inferior thyreoid passes behind the carotid trunk.
Fourth. Bifurcation of trachea. Second piece of aortic arch, extending from upper border of second right costal cartilage, reaches spine. Arch of vena azygos. The superior mediastinum is bounded behind by the upper four thoracic vertebrae. Louis' angle, junction of manubrium and gladiolus. Thoracic aorta begins.
Fifth to ninth. Base of heart.
Sixth. Pulmonary and aortic valves, opposite third left costal cartilage at its sternal junction, in front. Commencement of aorta and pulmonary artery. End of superior cava, third right chondro-sternal junction in front.
Tenth. Level of tip of xiphoid cartilage. Lower limit of lung posteriorly. Upper limit of Uver comes to the surface posteriorly. QDsophagus passes through diaphragm. Cardiac orifice of stomach (sometimes). Upper limit of spleen. .
greatest importance in determining the nature of shoulder injuries, can be made out here: — The clavicle in its whole extent, the acromion process, the great tuberosity, and upper part of the shaft of the humerus. Much less distinctly, the position of the coracoid process in the infraclavicular fossa and the head of the humerus through the axilla can be made out. The anterior margin of the clavicle, convex medially and concave laterally, can be made out in its whole extent, the bone, if traced laterally, being found not to be horizontal, but rising somewhat to its junction with the acromion. The stemo- and acromio-clavicular joints have been referred to at p. 1363.
The frequency of fracture of the clavicle is explained chiefly by its exposure to shocks of varied kinds from the upper extremity, inseparable from the out-rigger-like action of the bone and its early ossification. On the other hand, the main safeguards are the elasticity and curves of the bone, the way in which it is embedded in muscles which will damp vibrations, and the bufferbond fibro-cartilages at either extremity. The looseness and toughness of the overlying skin explain the rarity of compound fracture here. The junction of the two curves is the weakest spot and the usual site of fracture. The weight of the limb acting through the coraco-olavicular ligaments and overcoming the trapezius is the chief factor in the downward displacement; the pectoralis minor and serratus anterior acting on the scapula draw the acromial fragment forward. The tip of the acromion, when the arm hangs by the side with the hand supinated, is in the same Mne as the lateral condyle and the styloid process of the radius. On the medial side, the head and medial condyle of the humerus and the styloid process of the ulna are in the same line. Thus the great tuberosity looks laterally, the head medially, and the lesser tuberosity somewhat forward. Between the two tuberosities runs the intertubercular (bicipital) groove, which,
with the arm in the above position, looks directly forward. In thin subjects its lower part can be defined. Its position can be marked with sufficient accuracy by a Hne running downward from the acromion in the long axis of the humerus. Besides the tendon and its synovial sheath, the insertion of the latissimus dorsi, the humeral branch of the thoraco-acromial artery, and the anterior circumflex artery run in the groove. When the fingers are placed on the acromion and the thumb in the axilla, the lower edge of the glenoid cavity can be felt; and if the humerus be rotated (the elbow-joint being flexed), the head of the humerus can be felt also.
The characteristic roundness of the shoulder is due to the great tuberosity lying under the deltoid (fig. 1130). In dislocation the loss of this roundness is due to the absence of the head and tuberosity and consequent projection of the acromion.
This normal projection of the deltoid renders it impossible to place a flat straight body in contact with both the acromion and the lateral epicondyle at the same time (Hamilton's dislocation test). Below the junction of the lateral and middle thirds of the clavicle, between the contiguous origins of the pectoralis major and deltoid, is the infraclavicular fossa, in which lie the cephalic vein, the deltoid branch of the thoraco-acromial artery, and a lymphatic node which may be involved in obstinate tuberculosis of the cervical groups. On pressing deeply here, the coracoid process can be made out if the muscles are relaxed, and the axillary artery compressed against the second rib.
On raising the arm and abducting it, the different parts of the deltoid can often be made out — viz., fibres from the lower border of the spine of the scapula, the lateral edge of the acromion, and the lateral third or more of the front of the clavicle; the characteristic knitting of the surface
owing to the presence of fibrous septa continuous, alike, with the skin and the sheath of the muscle and the tendinous septa which separate the muscular bundles, will also be seen. The muscle will be marked out by a base-line reaching along the above bony points, and two sides converging from its extremities to the apex, a point on the lateral surface of the humerus, about its centre. In paralysis of the deltoid, the humerus being no longer braced up against the scapula, the finger-tips can be placed between it and the acromion.
To map out the pectoralis major, a line should be drawn down the lateral aspect of the sternum as far as the sixth costal cartilage, and then two others marking the borders of the muscle — the upper corresponding to the medial border of the deltoid, the lower starting from the sixth cartilage, and the two converging to the folded tendon, which is inserted as a double
layer into the lateral tubercular (bicipital) ridge. The pectoralis minor will be marked out by two lines, from the upper border of the third and the lower border of the fifth rib, just lateral to their cartilages, and meeting at the coracoid process. The lower line gives the level of the long thoracic artery; the upper, where it meets the line of the axillary artery, that of the thoracoacromial.
When the arm is abducted and the humerus rotated a httle laterally, the prominence of a well-developed coraco-brachialis comes into view; a Une drawn from the centre of the clavicle along the medial border of this muscle to its insertion into the humerus gives the Une of the axillary artery.
the vessels and nerves in relation to them, must be remembered. The chief vessels are the axillary on the lateral wall, brought into prominence when the arm is abducted, as in removal of the mamma, and the subscapular on the posterior wall. The apex is felt, when the finger is pushed upward in an operation here, to be bounded by the clavicle in front, the first rib behind, and the coracoid somewhat laterally. The base is concave, owing to the coraco-clavicular (costocoracoid) membrane as it descends to blend with the sheath of the pectoralis minor, giving also a process to the axillary fascia which unites the anterior and posterior boundaries. This process also sends septa to the skin.
An axillary abscess, always to be opened early to avoid subsequent interference with the movements of the shoulder, is reached by an incision on the medial wall, midway between the anterior and posterior boundaries, so as to avoid the long thoracic and subscapular vessels, respectively, the back of the knife being directed toward the lateral wall. The only vessel on this wall is the superior thoracic, which lies high up. Additional safety is given by the use of Hilton's method. For exploration of the axilla the best incision is an angular one, the two limbs being placed in a line with the anterior margin of the great pectoral, and in the line of the axillary vessels. This runs from a point on the centre of the clavicle (the limb being at a right angle to the trunk) to the medial margin of the coraco-brachialis. If this be obliterated by swelling, the above line should be prolonged to the middle of the bend of the elbow, which will give the guide to the brachial also. Collateral circulation. If the first part of the artery be tied, the channels are the same as in ligature of the third part of the subclavian {q.v.). In ligature of the third part of the axillary, if the ligature be above the circumflex arteries, the chief vessels concerned are the transverse scapular (suprascapular) and thoraco-acromial above and the
posterior circumflex below. If the ligature be below the circumflex, the anastomoses will be those concerned in ligature of the brachial above the profunda (p. 1414). The lymphatic nodes in the axilla have been mentioned at p. 719, (fig. 566).
The depression of the axillary fossa is best marked when the arm is raised from the side to an angle of about 45°, and when the muscles bounding it in front and behind are contracted. . In proportion as the arm is raised, the hollow becomes less, the head of the humerus now projecting into it. When the folds are relaxed by bringing the arm to the side, the fingers can be pushed into the space so as to examine it.
The axiUary (circumflex) nerve and posterior circumflex vessels wind around the humerus under the deltoid; a hne drawn at a right angle to the humerus and a little above the centre of this muscle marks their position on the surface.
To trace the synovial membrane of the shoulder -joint is a comparatively simple matter (fig. 11.30). Covering both aspects of the free edge of the glenoid ligament, it lines the inner aspect of the capsule, whereb.y it reaches the articular margin of the head of the humerus; there is a distinct reflection, below, from the capsule on to the humeral neck before the rim of the cartilage is reached.
An extensive protrusion of synovial membrane takes place in the form of a synovial bursa, at the medial and anterior part of the capsule, near the root of the coracoid process under the tendon of the subscapularis. Another protrusion takes place between the two tuberosities along the intertubercular groove, as low as the insertion of the pectoralis major. A third synovial protrusion may be seen, but not frequently, at the lateral or posterior aspect, in the form of a bursa, under the infra-spinatus tendon. Thus the continuity of the capsule is interrupted by two and sometimes three synovial protrusions.
Shoulder-joint. — The frequency of dislocations here, nearly equal to those of all the other joints put together, calls attention to the points contributing to make the joint alike insecure and safe. Strength is given by (1) the intimate blending of the short scapular muscles, especially the subscapularis with the capsule; (2) the coraco-acromial vault; (3) atmospheric pressure; (4) the long tendon of the biceps; (5) the elasticity of the clavicle; (6) the mobility of the scapula. The weakness of the joint is readily explained by its free mobility, the want of correspondence between the articular surfaces, its exposure to injury, and the length of the humeral lever. The rent in the capsule is usually anterior and below, and to this spot the head of the humerus must be made to return. While dislocations are usually primarily subglenoid, owing to the above part of the capsule being the thinnest and least protected, they take usually a secondarily forward direction,
the groove.
as the triceps prevents the head passing backward. In addition to the above features of the lower part of the capsule, laxity is here also a marked feature, to allow of free abduction and elevation. This movement wall be accordingly much checked by any inflammatory matting of this part of the capsule.
The best incision for exploring the joint is one commencing midway between the coracoid and acromion processes and carried downward parallel with the anterior fibres of the deltoid. The cephaUc vein and biceps tendon are to be avoided. If drainage is needed, it must be BuppUed by a counter-incision behind. This may be made along the posterior border of the deltoid, part of its humeral attachment being detached if necessary. The axillary (circumflex) nerve must be avoided in the upper part of the incision.
The shaft of the humerus is well covered by muscles in the greater part of its extent, especially above. Below the insertion of the deltoid, the lateral border of the bone can be traced downward into the lateral supracondyloid ridge. The medial border and ridge are less prominent.
Attached to these ridges and borders are the intermuscular septa, each lying between the triceps and brachiaUs (anterior), and the lateral one giving origin to the brachio-radialis (supinator longus) and extensor carpi radialis longus as well. The medial extends up to the insertion of the coraco-braohialis, the lateral to that of the deltoid. The lateral septum is perforated by the anterior part of the profunda vessels and the radial (musculo-spiral) nerve, the medial by the superior and posterior branch of the inferior ulnar collateral (anastomotica magna) artery and the ulnar nerve.
The biceps has a two-fold attachment above and below. The former is of much importance in steadying the various movements, especially the upward one, and in harmonising the simultaneous flexion and extension of the shoulder- and elbow-joints. (Cleland.) The lacertus fibrosus curving downward and medially with its semilunar edge upward, across the termination of the brachial artery, strengthens the deep fascia and the origin of the flexors of the forearm. The two heads unite in the lower third of the arm. The tendon, before its insertion, becomes twisted, the lateral border becoming anterior.
Superior ulnar collateral vessels
On either side of the well-known prominence of the biceps is a furrow. Along the lateral ascends the cephahc vein. The medial corresponds to the line of the basilic vein which lies superficial to the deep fascia below the middle of the arm, and superficial and medial to the brachial vessels and median nerve.
The strength of such muscles as the deltoid, and their intimate connection with the periosteum of the humerus, account for fracture of this bone by muscular action being more common than elsewhere. The presence of muscular tissue between the fragments, together with deficient immobiUzation, explains the fact that ununited fractures are also most common in the humerus. The best incisions for exploring the humerus, e. g., in acute necrosis, etc., are (a) for the upper portion, the two already mentioned along the anterior and posterior borders of the deltoid. In the latter case the presence of the radial (musculo-spiral) nerve in the deeper part of the wound must be remembered; (6) for the lower end one parallel with the lateral intermuscular septum, deepened between the brachialis and brachio-radialis.
A line drawn along the medial edge of the biceps from the insertion of the teres major to the middle of the bend of the elbow corresponds to the brachial artery. In the upper two-thirds, this artery can be compressed against the bone by pressure laterally; in its lower third the humerus is behind it, and pressure should be made backward. The presence of the median nerve will interfere with any prolonged digital pressure applied in the middle of the arm.
In ligature of the artery here the line extends from the mid-axillary region above, prolonged to the centre of the front of the elbow. The only structures seen should be the medial edge of the biceps, the basilic vein, and the median nerve. The profunda comes off 2.5 cm. (1 in.) below the teres major, having the same relation to the heads of the triceps; thus, it first lies on the long head, behind the axillary and brachial arteries, then between the long and medial heads, and next, in the groove, between the medial and lateral heads, and courses with the radial (musculo-spiral) nerve (fig. 1132); the nutrient artery arises opposite the middle of the humerus; in many cases it arises, on the back of the arm, from the profunda; the superior ulnar collateral (inferior profunda) below the middle, and courses with the ulnar nerve through the intermuscular septum to the back of the medial condyle. The inferior ulnar collateral (anastomotica magna) is given off from 2.5 to 5 cm. (1 to 2 in.) above the bend of the elbow. Fig. 1138 will show the collateral circulation after ligature of the brachial, according as the vessel is tied above or below the superior profunda, or below the superior ulnar collateral.
The centre of the arm is a landmark for many anatomical structures. On the lateral side is the insertion of the deltoid; on the medial, that of the coracobrachialis. The basilic vein and the medial brachial cutaneous nerve (nerve of Wrisberg) here perforate the deep fascia, going in reverse directions. The superior ulnar collateral is here given off from the brachial and joins the ulnar nerve; the median nerve also crosses the artery, and the ulnar nerve leaves the medial side of the vessel to pass to the medial aspect of the limb.
The brachialis can be mapped out by two pointed processes which surround the insertion of the deltoid, pass downward into lines corresponding to the two intermuscular septa, and then converge over the front of the elbow to their insertion into the coronoid process.
The median nerve (lateral head, 5th. 6th, 7th C; medial head, Sth C. and 1st T.) can be traced by a line drawn from the lateral side of the third part of the axillary and first part of the brachial artery, across this latter vessel about its centre, and then along its medial border to the forearm, where it passes between the two heads of the pronator teres.
The ulnar nerve (Sth C. and 1st T.) lies to the medial side of the above arteries as far as the middle of the arm, where it leaves the brachial to course more medially and perforate the medial intermuscular septum together with the superior and posterior branch of the inferior ulnar collateral and so get to the back of the medial condyle. A line drawn from the medial border of the coraco-brachialis, where, in the upper part of its course, the nerve is in close relation with the medial side of the axillary and brachial arteries, to the back of the medial condyle, will indicate its course. Low down, the nerve is in the medial head of the triceps, and may be injured in operations here.
The radial (musculo-spiral) nerve (5th, 6th, 7th, and Sth C.) can be traced by a line beginning behind the third part of the axillary artery, then carried vertically down behind the uppermost part of the brachial, and then, just below the posterior border of the axilla, curving backward behind the humerus and slightly downward just below the insertion of the deltoid. Thus, passing from laterally and from before backward in its groove, accompanied by the profunda vessels, first the trunk, and then the smaller anterior division, it again comes to the front by perforating the lateral intermuscular septum at a point about opposite to the junction of the middle and lower thirds of the arm, and passes down in front of the lateral supracondyloid ridge, lying here between the brachio-radialis and brachialis anterior, to the level of the lateral condyle, in front of which it divides into the superficial (radial) and deep (posterior interosseous) radials. The former of these accompanies the radial artery to the front of the arm, the latter travels backward to the back of the forearm. A line from the lateral condyle to the insertion of the deltoid indicates the lateral intermuscular septum.
In addition to injuries caused by fracture, the nerve may be injured in crutch pressure, the sleep of intoxication, use of an Esmaroh's bandage, or the careless reduction of a dislocated shoulder with the foot in the axilla. To expose the nerve the incision begins below, over the lateral intermuscular septum, where it lies between the brachio-radialis and brachialis (anterior). Hence the incision is prolonged freely upward and backward toward the posterior border of the deltoid.
On the back of the arm is the triceps muscle, with its three heads and tendon of insertion, all brought into relief in a muscular subject when the forearm is strongly extended. Of the three heads, the medial is the least distinct, arising
below the groove (musculo-spiral) for the radial (musculo-spiral) nerve, reaching to each intermuscular septum, and tapering away above as high as the teres major. Most of the fibres of this head lie deeply. The lateral head, arising above the groove as high as the great tuberosity, appears in strong relief just below the deltoid; while the middle or long head, arising from the scapula just below the glenoid cavity, appears between the teres muscles. The tendon of insertion, passing into the upper and back part of the olecranon over a deep bursa, is shown by a somewhat depressed area. On the lateral side, an important expansion to the fascia over the anconeus is given off.
In the ossification of the humerus the epiphyses are of first importance. The upper, consisting of those for tlie head and two tuberosities, wliich form one about the seventh year, blends with the shaft between the twentieth and twentj'-fittli years. Separation usually takes place at an earlier date, this being explained by the fact that the cone-like arrangement by which the diaphysis fits into the cap of the epiphysis becomes more marked toward the date of union, and thus tends to prevent displacement. (Thomson.) The lower epiphysis. The condition of this varies with the degree of coalescence of its four centres. The first and chief, that for the capitulum (second or third year), unites with those for the trochlea and lateral epicondyle soon after puberty, and forms an epiphysis which joins with the shaft at about sixteen. The epiphysis for the medial epicondyle appears at the fifth year and unites with the shaft at the eighteenth. Injury to this epiphysis may damage the ulnar nerve and open the elbow-joint. Thus, at and after puberty, there are two chief epiphyses to remember here: — (a) the larger, consisting of capitular, trochlear, and lateral epicondyle centres. This is almost entirely intraarticular; (6) the smaller, that for the medial epicondyle; the extent to which this is intra-articular varies. The structures that would be divided in an amputation at the centre of the arm
THE ELBOW
are shown in fig. 1132. The chief points needing attention are: — (1) To leave as much of the lever of the humerus as possible; (2) clean section of the large nerves, the radial (musoulospiral) in its groove being especially liable to be frayed by the saw; (3) the difference between the amount of retraction of the free biceps in front, and the triceps behind, fixed to the bone and septa.
The bony points, epicondyles, olecranon, and head of radius, andtheir relation to one another, should be carefully studied. The medial epicondyle is the more prominent of the two, is directed backward as well as medially, and lies a little above its fellow. Above it can be traced upward the supracondyloid ridge and corresponding intermuscular septum. The lateral epicondyle is more rounded, and thus less prominent; below, and a little behind it, the head of the radius can be felt moving under the capitulum when the forearm is supinated and flexed. A depression marks this spot and corresponds to the interval between the anconeus and brachio-radialis and extensor carpi radialis longus; at the back, the upper part of the olecranon is covered by the triceps. The lower part is subcutaneous, and separated from the skin by a bursa. If the thumb and second finger be placed on the epicondyles and the index on the tip of the olecranon, and the forearm completely extended, the tip of the olecranon rises so as to be on the line joining the two epicondyles. In flexion at a right angle, the olecranon is below the line of the
Between the medial
epicondyle and olecranon is a pit, in which lie the ulnar nerve and the anastomosis between the inferior ulnar collateral and the posterior ulnar recurrent arteries. The coronoid process is so well covered by muscles, vessels, and nerves that its position cannot be distinctly made out.
The synovial membrane of the elbow-joint communicates with that of the superior radioulnar. Hence the facility with which tuberculous disease may be set up after neglected falls on the hand, in early life. At this time the weakness of the annular (orbicular) ligament leads to its being easily injured. Swelling, due to effusion into the joint, appears on either side of the triceps tendon, and soon obliterates the depression below the lateral epicondyle. The simplest incision for an infected elbow-joint is a vertical one, on the lateral side of the olecranon. A superficial swelling over the tip of the olecranon is due to effusion into the bursa between the soft parts and that bone. A deeper, less easily defined swelling in the same region is due to inflammation of the bursa between the olecranon and the triceps. A swelling on the medial side of the elbow-joint, if painful and accompanied by inflammation of the skin, may be due to mischief in the epitrochlear lymphatic node situated just above the medial epicondyle, and receiving lymphatics from the medial border of the forearm and the two medial fingers.
The hollow in front of the elbow. — The delicacy of the skin here must always be borne in mind in the application of splints. Owing to the insidious rapidity with which pressure may set up ischaemic paralysis, anterior angular splints are always to be used with caution. The M-like
arrangement of the superficial veins as usually described is by no means constant (fig. 1136), The median basilic is the vein usually chosen for venesection, owing to its larger size and its being firmly supported by the subjacent bicipital fascia which separates it from the brachial artery; but the median cephalic is the safer. The median basilic is crossed by branches of the medial antibrachial (internal) cutaneous nerve, while those of the musculo-cutaneous lie under the median cephalic. In the semiflexed position, the fold of the elbow is seen, a little above the level of the joint. This forms the base of the triangular fossa below the elbow, the lateral side corresponding to the brachio-radialis, the medial to the pronator teres, and the apex to the meeting of these muscles. The tendon of the biceps can be easih' made out in the centre of the fossa, giving off above the lacertus fibrosus from its medial side to fasten down the flexors of the forearm. Under the tendon on its medial side lie the bracliial artery and the median nerve, a little medial to it, for a short distance. The radial nerve (musculo-spiral) lies outside the fossa, between the brachio-radialis and the brachialis (anterior), and gives off its two
site to the neck of the radius.
The arterial anastomoses about the elbow-joint are as follows: The radial recurrent runs up unaer cover of the brachio-radialis to anastomose with the anterior branch of the profunda on the front of the lateral condyle. The posterior interosseous recurrent ascends, between the supinator and the anconeus, to anastomose on the back of the lateral condyle with the posterior branch of the profunda. It further joins, by a large anastomotic arch across the back of the joint, with the inferior ulnar collateral (anastomofic magna) and posterior ulnar recurrent. The anterior ulnar recurrent passes upward on the brachialis to join the anterior part of the inferior ulnar collateral under the pronator teres, on the front of the medial epicondyle. The posterior ulnar recin-rent makes for the interval between the back of the medial epicondyle and the olecranon, to join with the superior and the posterior branch of the inferior ulnar collateral.
Bony landmarks. — The -posterior border of the ulna can be easily traced down from the olecranon to the back of the styloid process; the bone becomes somewhat rounded below, and lies between the flexor and extensor carpi ulnaris. The tip of the styloid process corresponds to the medial end of the line of the wrist-joint. The radius is covered above by the brachio-radialis and radial extensors of the carpus, and the outline of the bone is less easily followed. Its styloid process is readily made out below a finger 's breadth above the thenar eminence. It is placed about 1.2 cm. (I in.) lower than that of the styloid process of the ulna.
Thus, a line drawn straight between the two processes would fall a little below that of the wrist-joint, this being shown by a line drawn between the two processes forming a slight curve, with its conoa\'ity downward (corresponding to the concavity of the lower surface of the radius and fibro-cartilage) about 1.2 cm. (5 in.) above the straight Une given above.
The bones are nearest to each
other in complete pronation, and farthest apart in complete supination. On section, the bones are found at every point nearer to the back than to the front of the limb, but increasingly so above. 'The lower the section proceeds down the Umb, the less will the bones be covered at the sides, and the more equally wUl the soft parts be distributed about the anterior and posterior aspects of the Umb. It will be noticed that where one bone is the more substantial, the other is the more slender, as near the elbow and wrist; and that it is about the centre of the limb that the two are most nearly of equal strength.' (Treves.) When the Hmb is pronated, the interosseous space is narrowed; in supination and the mid-position it is widened out. In pronation, both styloid processes can be distinctly made out; in supination, that of the radius is the more distinct, as now the skin and soft parts are stretched and raised over that of the ulna.
when the forearm is pronated, between the head of the ulna and lower end of the radius. The recessus sacciformis here may be enlarged in rheumatic and other affections. The interosseous membrane not only ties the bones together and gives attachment to muscles, but in falls on the hand it enables the ulna to participate in the shock.
The following are important points with regard to the bones. Common fractures. Olecranon.— This usually takes place at the constricted centre of the semilunar (greater sigmoid) notch or the junction of the olecranon with the shaft. A fall is here the usual cause, and the heavier the fall, the more frequently is the fracture nearer the shaft, though displacement is now likely to be slight, owing to the abundance of fibrous and muscular structures on both sides
Posterior interosseous from common interosseous of ulnar
of the fracture. The shaft of one or both hones. Usual site, about the middle or a little below it, fracture of the radius being more frequent from its connection with the hand. In these fractures the chief muscular agencies are — (1) the extensors and flexors in drawing the lower fragment or fragments upward, forward, or backward, according to the direction of the fracture; (2) the biceps in drawing the upper fragment of the radius upward; (3) the influence of the pronator teres, if the fracture is, as usual, below it, and (4) that of the quadratus in drawing the lower fragments together. Thus the chief practical points are — (a) the reduction of displacement, whether antero-posterior or lateral; (6) the greater the number of fragments, the greater the tendency to union across the interosseous space, with its embarrassing results, and the greater the need of a supinated position in the setting; (c) the risk of gangrene here from the faciUty with which the vessels are compressed against the contiguous bones, especially in flexion of the forearm; and the consequent need of attention to the width of the splints and the bandaging; (d) the readiness with which ischsemic paralysis may rapidly and insidiously be caused. Colles' fracture. Here, after a fall on the hand, the radius gives way usually at its weakest part, about
18 mm. (f in.) above its extremity, where the narrow compact tissue is suddenly expanding into cancellous. There is frequently impaction of the upper into the lower fragment. There is a three-fold displacement of the lower fragment: — (1) It is driven and drawn upward and backward. (2) It is rotated so that its articular surface looks somewhat backward. (3) It is drawn to the radial side. The chief causes of the discreditable stiffness often allowed to result are non-reduction of the deformity, adhesions in the opened wrist-joint, teno-synovitis, and prolonged immobilisation.
Separation of epiphysis. — This may take place in the radius up to about the age of eighteen: it is commoner before. Its possible importance in interfering with the symmetry of the growth of the bones is obvious. Here, as in CoUes' fracture, the level of the styloid processes of the radius and ulna, and the correspondence of the two styloid processes of the radii, are important in diagnosis. Exposure of the bones. In the case of ununited fracture or necrosis the radius may be reached — (o) Behind, by an incision in a line drawn from the lateral epicondyle to the back of the radius. The field opened here lies between the brachio-radialis and the radial extensors on the one side, and the common extensor on the other. Care must be taken of the
deep radial (posterior interosseous) nerve. (6) In front. The incision here lies in the sulcus between the brachio-radialis and the flexors. The pronator teres and the flexor subUmis must, in part, be detached from the radius. If more room is required to reach an injured upper extremity of the radius, the incision will descend from above the lateral epicondyle in the groove between the anconeus and common extensors. In the detachment of the supinator the deep radial nerve will again need attention. The ulna is more easily reached by an incision between the flexor and extensor carpi ulnaris. In removal of the lower part of the bones for myeloid sarcoma or osteitis, the ulna is reached in the interval last mentioned. The radius is best exposed by an incision between the brachio-radialis and extensor carpi radialis longus, the superficial radial nerve being the guide. (Morris.) Finally, the so-called 'carrying angle' of the forearm deserves mention. In extension the bones of the forearm are not in a straight line with the humerus, but directed sUghtly laterally, the angle at the elbow-joint being obtuse, and open laterally. This angle is so named from its facilitating carrying objects during walking. In flexion the forearm is deflected somewhat toward the middle line, mouth, etc. These properties are liable to be lost under many and widely different conditions, of wliich injuries to the epiphyses of the humerus, badly united fractures of the forearm, and osteoarthritis of the elbow-joint are instances.
Soft, parts. — Along the lateral border, of the forearm descend the brachioradialis and radial extensors of the carpus, fleshy above, tendinous below. About 3.7 cm. (I5 in.) above the styloid process of the radius, a fleshy swelling directed obliquely downward and forward from behind, across this lateral border of the forearm, denotes the extensors of the thumb crossing those of the carpus.
Along the medial border is the fleshy mass of the pronator teres and flexors, the ulna being covered by the flexor carpi ulnaris and flexor profundus. The tendon of the pronator is inserted into the radius a little below its centre — a point of importance in the treatment of fractures and in amputation. The flexor carpi ulnaris tendon can be felt just above the wrist making for the pisiform bone; and just lateral to it lies the ulnar artery, about to pass over the transverse carpal (anterior annular) ligament.
The course of the artery is denoted by the lower two-thirds of a hne drawn from the front of the medial epicondyle to the lateral edge of the pisiform bone. From the bifurcation of the brachial, a line drawn to meet the former at the junction of its middle and upper third marks the upper part of the artery, here thickly covered by muscles. In ligature of the artery in the middle of the forearm, the white line and sulcus between the flexor carpi ulnaris and sublimis must be identified. A small muscular branch will often lead down to the artery. The line of the ulnar nerve is one drawn from the interval between the medial epicondyle and the
olecranon to the medial side of the ulnar artery just above the wrist. The nerve joins the artery at the junction of the upper and middle thirds of the forearm. The median nerve runs in a hne drawn from the medial side of the brachial artery, in the elbow triangle, to a point beneath, or just to the medial side of, the palmaris longus at the mid-point of the front of the wrist. The radial artery will be marked by a line drawn from the centre of the bend of the elbow (where the brachial artery divides opposite to the neck of the radius) to a point just medial to the radial styloid process descending along the medial edge of the brachio-radialis. The muscular interval is that between the brachio-radialis and pronator teres above, and the flexor carpi radialis below. The superficial radial nerve will be marked by the same line (it lies just lateral to the artery) for its upper two-thirds; it then leaves the artery about 7.5 cm. (3 in.) above the wrist-joint, and passes to tiie back of the forearm under the tendon of the brachio-radialis. The volar interosseous artery runs down on the interosseous membrane and passes to the back of the forearm by perforating it below, having passed behind the pronator quadratus. The dorsal interosseous lies between the superficial and deep extensors. These small arteries reinforce the palmar through' the carpal arches, and thus bring down blood after ligature of the trunks above.
The front of the forearm is supplied by the miiscido-cutaneous on the lateral, and the medial aniibrachial (internal) cutaneous on the medial, side; just above the wrist the palmar cutaneous branches of the median and ulnar perforate the deep fascia (fig. 1140). The back of the forearm is supplied by the radial (mus-
The lymphatics of the upper extremity are superficial and deep; the former run with the superficial veins, the latter with the deep vessels. Occasionally a few small nodes occur below the elbow. The epitrochlear nodes lie upon the basilic vein, a little above the medial epicondyle and draining the fourth and fifth digits. The majority of the lymphatics open into the axillary nodes, and terminate, on the left side in the thoracic duct, on the right in the lymphatic duct. A few, accompanying the cephahc vein, reach the subclavian or infraclavicular nodes, and thus communicate with the lymphatics of the neck.
Paralysis of the median nerve. — (a) In forearm: Loss of pronation, (fe) At ivrisl: Diminished flexion 1111(1 tciidciicy toward ulnar adduction, (c) In the hand: Power of grasp is lessened especially in the tliunili and lateral two fingers. Owing to the loss of flexion in the phalanges of these fingers the phalanges are liable to become overextended by the action of the extensors and interossei. The thumb remains extended, adducted, and closely applied to the index, the human characteristic being thus lost, and the ' ape's hand' of Duchenne being produced. Sensation will be lost over the palmar aspect of the thumb and lateral two and one-half fingers and over the distal ends of the same fingers, to a varying degree, according to the sensory distribution of the median and other cutaneous nerves. The above apphes to lesions of the trunk. If the nerve be injured at the wrist, flexion of the wrist and fingers is less interfered with.
Paralysis of the ulnar nerve. — (a) At wrist: Power of flexion is diminished and that of ulnar adduction lost. (&) In the hand: Power of grasp will be lessened in the ring and little fingers. The interossei will be powerless to abduct or adduct the fingers, and there will be marked wasting of the interosseous spaces and hypothenar eminence. The thumb cannot be adducted. After a time, from paralysis of the lumbricals and interossei, the hand becomes 'clawed' — the first phalanges overextended, and the second and third flexed (main en griff e). Sensation will be lessened over the area supplied by the nerve.
Paralysis of the radial (musculo-spiral) nerve. — (a) In the forearm This is flexed, extension being impossible. The forearm is pronated, supination being impossible save by biceps, which acts now most strongly on a flexed elbow-joint, (b) In the wrist: This is dropped, owing to the loss of extension, (c) hi the hand: The thumb is flexed and adducted. Some slight power of extension of the second and third phalanges of the fingers remains by means of the lumbricales and interossei. Sensation is impaired over the posterior and lateral aspect of the forearm and lost to a varying extent over the distribution of the radial on the back of the hand.
Paralysis of the deep radial (posterior interosseous) nerve. — The evidence here is somewhat similar to that just given, but with the following differences, (o) In the forearm: There is no loss of extension, and the loss of supination is less as the brachio-radialis is not paralysed, (b) At the wrist: The 'drop' and loss of extension are not so marked, as the extensor carpi radiahs longus escapes. Sensation : There is no loss.
Paralysis of the musculo-cutaneous nerve. — Forearm: Power of flexion is impaired, owing to complete paralysis of the biceps and partial of the brachialis (anterior). Sensation: This is impaired over the lateral aspect of the forearm, both back and front.
Amputation of forearm. — The 'mixed' method by skin-flaps roundly arched and circular division of the soft parts, the dorsal flap being the longer, is the most generally applicable. The bones should always be sawn below the pronator teres, when possible. In sawing them they must be kept parallel, the limb being in the supinated position. As the radius is the less securely held above, it is well to complete the section of this bone first. The relative position of the vessels has been indicated above (p. 1423, and figs. 1139 and 1141).
THE WRIST AND HAND
Bony points. — On the medial side the styloid pi'ocess and, further laterally, the head of the ulna can be made out. On the lateral side, the radial styloid process descends about 1.2 cm. (| in.) lower than that of the radius, and is somewhat anterior to it. Abduction of the hand is thus less free than adduction. Between the apex of the styloid process and the ball of tlie thumb a bony ridge can be felt, with some difficulty, formed by the tubercle of the navicular and the ridge of the greater multangular (trapezium). At the base of the hypothenar eminence the pisiform can be more readily distinguished. The hook of the hamatum (unciform) lies below and to the radial side of the pisiform. On the front of the metacarpo-phalangeal joint of the thumb, the sesamoid bones can be distinguished.
At the back of the wrist and hand the triquetrum (cuneiform) bone can be felt below the head of the ulna; and more toward the middle line tlie prominence of the capitatum (os magnum), which supports the third or longest digit.
A line drawn from the base of the fifth metacarpal bone to the radio-carpal joint, slightly curved downward, will give the line of the carpo-metacarpal joints. (Windle.) When the fingers are flexed, it will be seen that in each case it is the proximal bone which forms the prom-
inence ; thus, the knuckle is formed by the head of the metacarpal, the interphalangeal prominence by the head of the first phalanx, and the distal one by the head of the second. _ Thus, the joint in each case lies below the prominence, the distal joint being 2 mm. {^t in.), the interphalangeal 4 mm. (i in.), and the metacarpo-phalangeal 8 mm. (3 in.) below its prominence.
Skin and skin-folds. — The skin over the palm is thickened over the heads of the metacarpal bones and hypothenar eminence, thinner over the thenar. It is peculiar in its absence of sebaceous glands and hair-follicles; hence the absence of boils and sebaceous cysts. It is intimately connected with the palmar fascia, hence the chief difficulty in operations when this is contracted. Over the pulp of the digits the skin is closely connected with the periosteum of each ungual phalanx. The importance of this is alluded to under the heading of whitlow (vide infra).
Skin -folds : two or three of these are seen on the palmar surface of the wrist : two lower down, and usually close together, and one less well marked, a little higher up upon the forearm. None of these corresponds exactly to the wrist-joint (fig. 1142). The lowest 'precisely crosses the arch of the OS magnum in the line of the third metacarpal bone' (Tillaux), and is not quite l.S cm. (f in.) below the arch of the wrist-joint. It is about 1.2 cm. (5 in.) above the carpo-metacarpal joint line, and indicates very fairly the upper border of the transverse carpal (anterior annular) ligament.
nence from the palm, ends at the lateral border of the hand and at the base of the index-finger. The second fold is slightly marked. It starts from the lateral border of the hand, where the first fold ends. It runs obliquely medially across the palm, with a marked inclination toward the wrist, and ends at the lateral Hmit of the hypothenar eminence. The third, lowest, and best marked of the folds starts from the little elevation opposite the cleft between the index and middle fingers, and runs nearly transversely to the ulnar border of the hand, crossing the hypothenar eminence at the upper end of its lower fourth. The first fold is produced by the adduction of the thumb; the second, mainly by the bending simultaneously of the metacarpo-phalangeal joints of the first and second fingers; and the third by the flexion of the three medial fingers. The second fold, as it crosses the third metacarpal bone, about corresponds to the lowest part of the superficial volar arch. The third fold crosses the necks of the metacarpal bones, and indicates pretty nearly the upper limits of the synovial sheaths for the flexor tendons of the three lateral fingers. A httle way below this fold, the palmar aponeurosis breaks up into its four slips, and midway between the fold and the webs of the fingers lie the metacarpo-phalangeal joints. Of the transverse folds across the fronts of the fingers, corresponding to the metacarpo-phalangeal and interphalangeal joints, the highest is placed nearly IS mm. (f in.) below its corresponding joint. The middle folds are multiple for all the fingers, and are exactly opposite to the first interphalangeal joints. The distal creases are single, and are placed a little above the corresponding joints. There are two single creases on the thumb cori-esponding to the two joints, the higher crossing the metacarpo-phalangeal joint obhquely. The free edge of the web of the fingers, measured from the palmar surface, is about 1.8 cm. (f in.) from the metacarpo-phalangeal joints. (Treves.)
of the pisiform bone, and then, a Httle lower, curving across the palm on a line with the thumb when outstretched at right angles with the index-finger. The four common digital arteries, the main branches of the superficial arch, run downward along the interosseous spaces, and bifurcate 12 mm. (J in.) above the webs of the fingers; the most medial digital does not bifurcate.
The digital arteries then descend along the sides of the fingers under the digital nerves, giving ofi twigs to the sheath of the tendons, which enter by apertures in it, and run in the vincula vasculosa. It is owing to the readiness with which these tiny twigs are strangled by inflammation that sloughing of the tendon takes place so readily and irreparably. Throughout its course the superficial volar arch deserves its name. It is only covered by the palmaris
tendons and lumbricales.
The deep volar arch, formed by the radial and communicating branch of the ulnar, lies about 1 . 2 cm. (| in.) nearer to the wrist than the superficial. It is not so curved as the superficial arch, and rests upon the interossei and metacarpal bones just below their bases. The structures separating it from the superficial arch have been already given.
brachio-radialis and flexor carpi radialis. Next to this tendon is the palmaris longus, when present. At the mid-point of the front of the wrist and usually under the palmaris longus is the median nerve. To the medial side of the palmaris longus is the flexor sublimis, the tendons for the middle and ring-finger being in front. The tendon of the flexor carpi ulnaris is most medial and between this and the superficial flexor of the finger the ulnar nerve and vessels have come up into a superficial position.
profundus
Fasciae and sheaths. — The transverse and dorsal carpal (annular) ligaments bind down and hold in place the numerous tendons about the wrist. The transverse carpal (anterior annular) , when healthy, cannot be detected. It is attached to the pisiform and triquetral (cuneiform) bones on the medial, and to the navicular and greater multangular (trapezium) on the lateral, side.
The ulnar nerve and vessels, the superficial volar, and palmar cutaneous branches of the median and ulnar pass over it. The ulnar artery and nerve are especially protected by their position between the pisiform and hook of the hamate (unciform), and also by a process of the flexor carpi ulnaris, which passes to the transverse ligament, thus forming a kind of tunnel. The flexor carpi radialis passes through a separate sheath formed by the ligaments and the groove in the greater multangular; while beneath the Hgaments lie the flexor tendons, the median nerve, and accompanying artery. Attached to its upper border is the deep fascia of the forearm, and to its lower the palmar fascia and the palmaris longus tendon, while from the lateral and medial parts arise some of the thenar and hypothenar muscles. The upper border of the transverse carpal ligament corresponds to the lower of the two lines which
cross the wrist just above the thenar and hypothenar eminences. The large synovial sheath, for all the flexors of the fingers, reaches beneath and below the transverse ligaments as far as the middle of the palm, and above the wrist for 3.7 to 5 cm. (1 J to 2 in.).
The dorsal carpal (posterior annular) ligament is attached to the back of the lateral margin of the radius above the styloid process, and medially to the back of the styloid process of the ulna, the triquetrum and pisiform. Its direction is obhque, being higher on the radial side. It contains six tendon-compartments, of which four are on the radius.
The most lateral contains the long abductor and short extensor of the thumb; the second the two radial extensors of the carpus; the third, the extensor pollicis longus; this deep and narrow groove can be identified when the hand is extended, by its prominent lateral margin; the fourth transmits the extensor communis and extensor indicis proprius; the fifth, lying between the
radius and ulna, the extensor digiti quinti; and the sixth, lying just lateral to the styloid process of the ulna, the extensor carpi ulnaris. The sheaths for the last two extensors are the only ones which follow the tendons of their insertion, the others ending at a varying distance below the carpal ligament. The lower border of the dorsal carpal corresponds to the upper margin of the transverse carpal ligament.
Sheath of flexores sublimis and profundus digitorum and flexor pollicis longus enclosed by the transverse carpal ligament Cut tendon of palmaris longus Ulnar nerve
The palmar aponeurosis, by its strength, toughness, numerous attachments, and intimate connection with the superficial fascia and skin is well adapted to protect the parts beneath from pressure.
at its attachment to the carpal ligament, spreads out fan-like below, and gives off four sKps, each of which bifurcates into two processes, which are attached to the sides of the first phalanx of each finger and into the superficial transverse ligament of the web and the deeper one which ties the heads of the metacarpal bones together. Transverse fibres pass between the processes into which each of the four slips bifurcates, and thus form the beginning of the theca, which is continued down the finger to the base of the last phalanx. It is the contraction of the palmar aponeurosis, especially of the slip to the two medial fingers, which gives rise to Dupuytren's contraction. The theca is strong opposite the first two phalanges (hgamentum vaginale), weak and loose opposite the joints (ligamentum annulare). The density of this osseo-fibrous tunnel and its close proximity to the digital nerves explain the pain in thecal inflammation. Its tendency to gape widely after section is to be remembered in amputations through infected parts.
Sjraovial membranes. — Beneath the transverse carpal ligament lie two synovial sacs, one for the flexor pollicis longus, and one for the superficial and deep flexors of the fingers. They extend above the transverse ligament for rather more than 2.5 cm. (1 in.). The two sacs may communicate. A compound palmar ganglion has an hour-glass outline, the transverse carpal ligament forming the constriction.
The creaking sensation in teno-synovitis and that of 'melon-seed' bodies often present in tuberculosis here is well known. The sheath for the long flexor of the thumb reaches to the base of the last phalanx. That for the finger-flexors gives off four processes. The one for the little finger also reaches to the base of the last phalanx. Those for the index-, middle, and third fingers end about the middle of the metacarpal bones. Traced from the insertions of the flexor
profundus, the digital synovial sheaths extend upward into the palm as far as the bifurcation of the palmar fascia (p. 1430), i. e., into a point about opposite to the necks of the metacarpal bones, denoted on the surface by the crease which corresponds to the flexion of the fingers. Thus, about 1 - 2 cm. (|in.) separates the sheaths of the lateral three fingers from the large synovial sac beneath the transverse carpal ligament. There is no synovial sheath beneath the pulp of the fingers or thumb, this part lying on the periosteum of the last phalanx.
This has an important bearing on whitlow. Infection here may be merely subcuticular, or deeper, in the latter case from the connection of the skin with the periosteum here existing the bone is soon affected, and necrosis keeps up a tedious ulcer. As the two centres of the phalanx do not unite till about the twentieth year, the distal one only requires removal; as the flexor sheath only reaches to the insertion of the flexor, i. e., into the proximal, part of the bone, both sheath and tendon may escape implication. Higher up along the fingers whitlow may be cellulo-cutaneous or thecal. While the continuity of the synovial sheath in the httle finger and thumb (fig. 1149) renders infection here more dangerous, the short gap between the digital and the palmar sacs is readily traversed by acute infection, with all the grave results of thecal suppuration.
Suppuration in the hand owes much of its gravity to the possibility of infection of the synovial tendon sheaths and consequent sloughing of the tendons. At the same time it is now recognised that unless these sheaths are primarily infected pus collects at first in certain jiotential spaces, more or less well defined, in the looser connective tissue of the hand. One of these, known as the middle palmar space (Kanavel*) is situated on the front of the metacarpals of the middle and ring fingers, and lies deeply between the flexor tendons and the interosseous muscles. Continuations of this potential space extend downward along the lumbrical muscles
on the radial side of the three medial fingers, and may lead pus from the palm to the subcutaneous tissue of these fingers or vice versa. A second potential compartment, the thenar space (Kanavel) lies in front of the index metacarpal, between the flexors of the index-finger and the adductor transversus poUicis. As in the former space, the corresponding lumbrical muscle prolongs it down to the radial side of the index -finger.
Distention of the middle pahnar space with pus leads to obliteration of the hollow of the palm and a variable extension of the swelling along the radial side of the three medial fingers. Distention of the thenar space follows the thenar eminence, obliterates the adduction crease of
the thumb, and may extend down the radial side of the index-finger. There is not in either case the extreme tenderness and pain on passive extension of the fingers that is characteristic of infection of the synovial sheaths. The pus is best evacuated by an incision on the radial side of the finger most affected, a little beliind the web, sinus forceps being passed along the lumbrical muscle into the palm, so as to avoid opening and infecting the synovial sheaths.
Deeper are the articular synovial sacs, five in number: — (1) Between the interarticular cartilage and the head of the ulna; (2) between the radius and the interarticular cartilage above, and the navicular and lunate and triquetrum below; (3) between the greater multangular and first metacarpal bone; (4) between the pisiform and the triquetral bone; (5) between the two rows of carpal bones, sending two processes upward between the three bones of the upper row, and three downward between the four of the lower row; these three processes being also continued below into the medial four carpo-metacarpal and three intermetacarpal joints.
Beneath the palmar aponeurosis covering the thenar eminence are the following structures: — Superficial volar artery, abductor pollicis brevis, opponens pollicis, radial head of short flexor, tendon of long flexor, ulnar head of short flexor, first volar metacarpal arteries, metacarpal bone of the thumb, with the tendon of the flexor carpi radialis and greater multangular.
Beneath the central part of the palmar aponeurosis are the superficial arch and its digital branches; the ulnar and median nerves, with their branches; the lle.xors, superficial and deep, with their synovial sheath; and the lumbricales; then a layer of connective tissue (the only
Fig. 1152. — Diagrams Illustrating the Insertions of the Extensor, Litmbrical and Interosseous Muscles op the Right Hand. A, Index finger. B, Middle finger. C, Ring finger. D, Little finger. IL, 2L, 3L, 4L, Lumbricales. 1D9, 2D9, 3E)9, 4D9, dorsal interossei. 1P9, 2P9, 3P9, palmar (volar) interossei. EC, Extensor communis digitorum. E9, Extensor indicis proprius. EMD, Extensor digiti quinti proprius. AMD, abductor digiti quinti (Willan : Anat. Anz. Bd. 42, 1912.)
structure, together with the deep layer of fascia over the interossei, which prevents matter pent in by the palmar aponeurosis from making its way back out through the dorsum), the deep arch, the interossei, and the metacarpal bones.
In the hypothenar eminence under the fascia are part of the ulnar artery and nerve, the abductor and flexor brevis digiti quinti, the opponens, the deep branch of the ulnar artery and nerve, and the fifth metacarpal bone.
The back of the wrist and hand. — The dorsal carpal (posterior annular) ligament has already been described. On the lateral side is the so-called 'snuff-box space' (tabatiere anatomique of Cloquet), a triangular hollow, bounded toward the radius by the long abductor and short extensor of the thumb, and toward the ulna by the long extensor. The navicular and greater multangular, ^dth their dorsal ligaments, form the floor. In the roof lie the radial vein and branches of the radial nerve. More deeply is the artery, following a line from the apex of the styloid process to the back of the interosseous space.
The different tendons have already been given. Between the first two metacarpal bones is the first dorsal interosseous muscle, wliich forms a fleshy projection against the radial side of the index metacarpal, when the thumb and index are pressed together. On its palmar aspect is the adductor polUcis. Wasting of the former muscle is a ready indication of injury or disease of the ulnar nerve.
The skin on the dorsum, by its laxity, readily allows of cedema, this being sometimes evidence of pressure on the axillary vein by carcinomatous deposits. The dorsal venous arch receives the digital plexuses, and from it the radial and posterior ulnar veins ascend. The median vein begins in plexuses at the root of the thumb and the front of the wrist.
Ganglia are common on the dorsum, in connection with the extensors of the fingers and the thumb. While usually due to a weakening of the sheath and protrusion of this and the synovial membrane, such swellings may be due to a projection of the articular synovial membrane. Owing to the laxity of the skin, the slight vascularity, the size of the tendons, their connection with joint-capsules and with each other, which fixes them, the dorsum of the wrist is the 'seat of election,' for tendon-anastomosis and other operations. Metacarpo-phalangeal dislocation. This ocom's in the thumb and the index-finger especially. The chief cause in the difficulty in reduction is the glenoid ligament. This, in reality a fibro-cartilaginous plate, is blended with the lateral ligaments on the palmar aspect of the joint, and is firmly attached to the phalanx, but more loosely to the metacarpal. Thus when dislocation occurs in violent hyperextension, the metacarpal attachment of the glenoid ligament gives way and it is carried by the phalanx over the head of the metacarpal bone. In the case of the thumb, the buttonhole-like slit with which the two heads of the flexor brevis, now displaced, embrace the head of the metacarpal, the contraction of the other short muscles, and, occasionally, a displaced long flexor, are additional causes. In the case both of the thumb and finger, tilting the phalanx well back on the dorsum of the metacarpal and then combined pressure with the thumbs forward against the base of the phalanx, when this is sharply flexed, will with an anaesthetic, be usually successful. The thumb should he, first, adduoted into the palm.
follows: hip and thigh, knee and leg, ankle and foot.
Bony landmarks. — Many of these, such as the anterior superior iliac spine and crest of the ilium and the tubercle of the pubis, have already been mentioned. The relative length of the limbs is obtained by carrying the measure from the anterior superior spine to the tip of the corresponding medial malleolus. The pelvis must be horizontal and the limbs parallel. The share taken by the femur and tibia respectively is estimated by finding the transverse sulcus which marks their meeting-point.
The head and shaft of the femur are well covered in, save in the emaciated. The head lies just below Poupart's ligament, under the ilio-psoas, and a little to the outer side of the centre of that ligament. A line drawn horizontally laterally from the pubic tubercle will cross the lower part of the head. All the head and the front of the neck, but only two-thirds of the back, are within the capsule; this intra-capsular position of the upper epiphysis, which, appearing at the first year, does not unite till eighteen or twenty, accounts largely for the extreme gravity of acute epiphysitis here. The structure of the neck, i. e., the two sets of lamellae, vertical to support the weight, transverse and intersecting in order to meet the puU of the muscles, and the wasting of these after middle life, has an important influence on injuries. The strong process, femoral spur or calcar (Merkel) which, arising from the compact tissue on the medial and under side of the neck, just above the lesser trochanter, spreads laterally toward the trochanteric (digital) fossa, also affords strength, and its degeneration probably plays an important part in the fractures of the neck.
Hip-joint. — The chief points of surgical importance are the following: — The capsule shows fibres chiefly longitudinal in front, circular behind. Of the former, the ilio-femoral or inverted Y-shaped hgament descends fi-om the anterior inferior spine to the two extremities of the anterior intertrochanteric line. It not only checks extension and strengthens the front of the joint, but it keeps the pelvis and trunk propped forward on the heads of the femurs, thus preventing waste of muscular action. It is joined on the medial side by the pubo-capsular ligament, which checks abduction. Between the two is the medial part of the front capsule, and here the ilio-psoas bursa may communicate with the joint. This fact must be remembered in tuberculous disease of the psoas, and the presence of this bursa explains certain deep-seated swellings in the front of the joint in adults. Behind, the ischio-femoral is the strongest part of the capsule, its fibres blending with the circular and weaker part of the capsule here. Dislocation usually occurs at the posterior, lower and medial part of the joint. It is to be noted that in full extension and flexion the head of the femur is in contact with the weakest spot in the capsule, in front and behind, respectively. From the deep aspect of the capsule fibres pass up at the line of reflection of the synovial membrane on to the neck- — the cervica,! Hgaments of Stanley. In intracapsular fracture these
softening may explain, a little later, an increase in the shortening.
Exploration of the joint. — This is usually effected by an oblique incision downward and slightly medially between the sartorius and rectus medially and the gluteus medius and minimus laterally. A branch of the ascending division of the lateral cu-oumflex is the only artery met with. In tapping the joint the puncture is made in the same line, 2 or 3 inches below the anterior-superior spine. 'If the instrument is pushed upward, medially, and backward beneath the rectus, it will pass into the joint a little above the anterior intertrochanteric Kne. (Stiles.)
femur is everted.
The chief structure of importance between it and the skin is the upper part of the insertion of the gluteus maxim us, that going to the fascia lata, and the bursa beneath the muscle. Tliis is often multilocular. It is, not very uncommonly, the seat of tubercular inflammation which readily invades the cancellous tissue of the trochanter. The top of the great trochanter is about 1.8 cm. (f in.) below the level of the femoral head, and, when the femur is extended is a little below the centre of the hip-joint. This part of the bone is covered by the gluteus medius.
The slightness of the prominence of the great trochanter in the living subject compared with that in the skeleton is explained by fig. 1154, which shows how the descending gluteus medius and minimus fill up the space between the ilium and trochanter. To examine the great trochanter, the thigh should be abducted, so as to relax the strong fascia lata passing upward over the tensor and glutei to the iliac crest.
Nelaton's line. — This useful guide is a line drawn from the anterior superior spine of the ilium to the most prominent part of the tuberositj^ of the ischium. In normal limbs, the top of the great trochanter just touches this line. In dislocation, fractures of the neck, and in wasting of the neck, as in osteo-arthritis, the relation of the trochanter to Nelaton's line becomes altered.
The top of the gi'eat trochanter is a guide in Adams's operation for division of the neck of an ankylosed femur, the puncture being made and the saw entered 2.5 cm. (1 in.) above and about the same distance in front of this point. Owing to the fact that in many cases of ankylosis the neck is destroyed, the above operation has been largely replaced by the simpler and more widely applicable Gant's osteotomy just below the great trochanter, from the lateral side.
Bryant's triangle. — Bryant makes use of the following in deciding the position of the great trochanter. The patient being flat on his back (1) a line is dropped vertically on to the couch from the anterior superior spine; (2) from the top of the great trochanter a straight Hne in the long axis of the thigh is drawn to meet the first; (3) to complete the triangle, a line is drawn from the anterior superior spine to the top of the trochanter. This line is practically Nelaton's. The second line will be found diminished on the damaged or diseased side.
Muscular prominences. — The tensor fasciw latoe forms a prominence beginning just lateral to the sartorius and reaching downward and somewhat backward to the strong fascia lata, 7.5 to 10 cm. (3 to 4 in.) below the great trochanter. Below this point, as far as the lateral condyle of the tibia, the strong ilio-libial band can be felt. Like the inverted Y-shaped Ugament, this band is a powerful saving of muscular action in maintaining the erect position. At the insertion of the tensor fascis lata3 it bifurcates into two layers, which enclose the muscle. The superficial is attached to the iliac crest and the sheath of the gluteus medius; the deep blends with the capsule and the reflected head of the rectus. This deeper layer is perforated by the ascending branch of the lateral circumflex. The ilio-tibial band is a guide for reaching the femur (p. 1334). The sartorius, the chief landmark of the thigh, forming a boundary of the femoral trigone (Scarpa's triangle), the adductor (Hunter's) canal, and the popUteal space, can be readily brought into view by the patient's raising his limb slightly rotated laterally. In the middle line the rectus muscle stands out in bold relief, with its tendon of insertion and the patella, when the
THE HIP AND THIGH
leg is extended. On either side of this muscle is a furrow, and on either side, again, of this furrow the vasti become prominent. Between the vastus medialis and adductor muscles is a depression indicating the adductor canal. At the upper and medial third of the thigh, if the limb be abducted, the upper part of the adductor longiis comes into strong reUef . On the medial side below, above the knee-joint, the vertical fibres of the adductor magnus end in a powerfxil tendon coming down to the adductor tubercle (fig. 1159). This replaces here the medial intermuscular septum, and the insertion of the tendon marks the level of the lower epiphysial Hne of the femur. At the lateral and back part of the thigh the vastus lateralis is separated from the biceps by a groove which indicates the lateral intermuscular septum. Of these septa, prolongations inward from the fascia lata to the linea aspera, the lateral lies between the vastus lateraUs and the biceps. It reaches from the lateral tuberosity of the femur to the insertion of the gluteus maximus. Just above the condyle it is perforated by the superior lateral articular vessel and nerve. The medial septum extends from the adductor tubercle to the trochanter. It is weak in
comparison, and separates the adductor from the vastus mediaUs. A third, the weakest of all, separates the adductor and the hamstrings. The fascia lata has the same effect as that in the neck in causing pus to burrow, especially downward, and in rendering the diagnosis of swellings beneath it difficult. Thickest above and on the lateral aspect, and again about the bony prominences at the knee-joint, at both of which sites it receives accessions from muscles, it is divided into iliac and pubic portions. The former is attached behind to sacrum and coccyx, iliac crest and the inguinal hgament, terminal Una and pubic tubercle. Here it blends with the pubic portion, which is connected with the pubic arch. At the fossa ovaUs (saphenous opening) the two may be said to separate, the iliac forming the upper cornu and lateral falciform margin, and descending over the femoral vessels and extensors. The pubic, much thinner, forms the medial margin of the fossa, and descends obliquely over the pectineus and adductor longus behind the vessels, to blend with the sheath of the ilio-psoas and capsule of the hip-joint.
The inguinal (Poupart's) ligament. — The abdomen is separated from the thigh by a fold, best marked in flexion — the inguinal furrow. In this, pressure detects the meeting of the aponeurosis of the external oblique and the fascia lata, i. e., Poupart's ligament, extending between the anterior superior spine of the ilium and the tubercle (spine) of the pubes. The line representing it should be drawn slightly convex downward, o^ving to the attachment of the deep fascia. It forms the base of the femoral trigone; its medial attachment blends with the triangular lacunar (Gimbernat's) ligament. The parts passing under the inguinal ligament and their arrangement have been given at p. 1399, fig. 1122.
The femoral trigone (Scarpa's triangle) (fig. 1159). — Immediately below the inguinal ligament a hollow is seen corresponding to this region, the lateral and medial boundaries of which are brought into view when the limb is raised, the adductor longus especially when the limb is abducted, and the sartorius when the thigh is flexed and the limb extended and rotated laterally. The floor of the femoral trigone is not horizontal, the plane of the medial part being very oblique. It is formed latero-medially by the ilio-psoas, pectineus, adductor brevis (slightly), and adductor longus.
A psoas abscess descending below the inguinal ligament usually does so on the lateral aspect of the femoral vessels; if the sheath gives way, or if the abscess follows the profunda artery, it will pass beneath the adductor longus and point toward the medial side of the thigh. (Taylor.)
Three nerves come into the thigh between the pelvis and Poupart's ligament, i. e., the lumbo-inguinal (genito-crural) in the femoral sheath, the femoral (anterior crural) between the iliacus and psoas and the lateral cutaneous close to the lateral attachment of the inguinal ligament.
The obturator nerve divides into two in the obturator foramen, the two divisions being separated by some fibres of the obturator externus, and lower down by the adductor brevis. The relations, course, and distribution of this nerve, in the medial fibres of the psoas, over the sacro-iliac joint and under the ilio-pelvic or sigmoid colon (Hilton), through the obturator foramen with its branches (from the superficial division) through the cotyloid notch to the hip, and (from the deep)
Patellar branch of saphenous
along the popliteal artery to the knee, and others to the lower third of the thigh, and sometimes the upper and medial aspect of the leg (Hilton), may be of much surgical importance, e. g., in carcinoma of the bowel, disease of the sacro-iliac and hip-joints, growths of the pelvis, and the rare obturator hernia. The distribution of the cutaneous nerves is shown in fig. 1158. Lying superficially in the base of the trigone, the inguinal lymphatic nodes can be detected in a thin person (fig. 1172).
The fossa ovalis (saphenous opening). — The depression corresponding to this Is placed just below the lacunar (Gimbernat's) ligament, with which its upper extremity blends. Its centre is about 3.7 cm. (11 in.) below and also lateral to a
line dropped vertically from the pubic tubercle. This and the other structures concerned in femoral hernia are fully described under this section (vide supra, p. 1398). The course of the great saphenous vein is given below, p. 1456.
Line of femoral artery. — A line drawn from the mid-point between the anterior superior spine and the symphysis pubis to the adductor tubercle will correspond with the course of this vessel. The sartorius usually crosses it 10 cm. ( 3 to 4 in.) below the inguinal (Poupart's) ligament. The profunda artery arises usually 3.7-5 cm. (1| to 2 in.) below Poupart's ligament.
The incision for tying tiie femoral in the femoral trigone should be about 7.5 cm. (3 in.) long, in the Kne of the artery, and begins about 7.5 cm. (3 in.) below the inguinal ligament, and runs over the apex of the triangle. The femur is flexed slightly, abducted and rotated laterally. The fascia lata being divided, the sartorius, readily recognised by its direction, is drawn laterally. The closely subjacent sheath must be opened on its lateral side. Structures that may be seen are a vein joining the great saphenous, the anterior cutaneous, saphenous nerve, and that to the vastus medialis. The collateral circulation (fig. 1156) is mainly through the following
channels: — (1) The lateral and medial circumflex above, with the genu suprema and lower muscular branches of the femoral, and the articular of the popliteal. (2) The perforating branches of the profunda above, with the vessels below first given. (3) The comes nervi iscliiadici with the articular of the popKteal.
The femoral vein Ues, below the inguinal ligament, immediately to the medial side of the artery. From this point on the vein gets to a somewhat deeper plane, though stOl very close to the artery, and gradually inclining backward, lies behind its companion at the apex of the triangle, and below lies somewhat laterally to it.
From the apex of the femoral trigone (Scarpa's triangle) a depression runs down along the medial aspect of the thigh, corresponding to the groove already mentioned between the vastus medialis muscle and the adductors. Along this groove lies the sartorius, and beneath it the adductor (Hunter's) canal, a triangular inter-muscular gap with its apex toward the linea aspera, and its base or roof formed by the fibrous expansion which ties together its boundaries, viz., the adductor longus and magnus and the vastus medialis.
The vein, which in the upper part of the canal lies behind the artery, separating it from the three adductors, lower down inclines more and more to the lateral side. The saphenous nerve lies also in the canal, but not in the sheath. The above-mentioned space terminates at about the junction of the middle and lower thirds of the thigh, in the opening in the adductor magnua
by which the artery enters the upper and medial part of the pophteal space. The saphenous, the largest branch of the femoral nerve, having crossed the femoral vessels latero-mediaUy, accompanies them as far as the opening in the adductor magnus. Here it perforates the aponeurotic roof, and is prolonged under the sartorius, accompanied by the superficial part of the genu suprema artery, to perforate the fascia lata between the sartorius and gracilis, and run with the great saphenous vein at the upper and medial part of the leg.
Pressure may be applied to the femoral artery — (1) Immediately below the inguinal ligament: it should here be directed backward so as to compress the vessel against the brim of the pelvis and the capsule of the hip-joint; (2) at the apex of the femoral trigone the pressure here being directed laterally and a little backward, so as to command the vessel against the bone; (3) in the adductor canal the pressure should be directed laterally with the same object. Care must be taken, especially above, to avoid the vein, which lies very close to the artery, and also the femoral nerve, which enters the thigh about 1.2 cm. (J in.) outside the artery, and at once breaks up into its branches, superficial and deep.
In ligature of the femoral artery in Hunter's canal, the line of the incision, in the middle third of the thigh, must exactly follow that of the vessel. It is frequently made too lateral, exposing the vastus medialis. Branches of the saphenous vein being removed, the fascia lata is slit up and the sartorius identified by its fibres descending medially. Those of the vastus medialis are less oblique and are directed downward and laterally. The sartorius having been drawn to the medial side, usually, the aponeurotic roof of the canal is opened, and the femoral sheath identified. The vein, here posterior and to the lateral side, is closely coimected to the artery.
The close contiguity of the femoral artery and vein accounts for the comparative frequency of arterio-venous aneurysms especially in the upper part, where the vessels are easily wounded. Their superficial position here further accounts for the facility with which mahgnant disease, e. g., epitheKomatous glands, may cause fatal ha;morrhage. Access to the femur. This is best attained on the lateral side of the shaft along the line of the lateral intermuscular septum (fig. 1160), the biceps being pulled backward, and the vastus lateralis detached anteriorly. On the medial side the bone may be exposed by an incision starting from a point midway between the inner margin of the patella and the adductor tubercle and passing obliquely upward and laterally, but the parts here are more vascular. Fractures of the shaft usually occur about the centre. The main tendency to displacement is of the lower fragment upward by the hamstrings. The upper fragment is anterior; this is especially marked in the upper third, owing to the action of the iho-psoas, which also rotates the upper fragment laterally. In the lower third the forward curve of the femur and its more superficial position explain the fact that it is here that compound fractures of the femur may, occasionally, occur. Ossification. The unstable nature of the tissues about the upper epiphysis, which appears at the end of the first year and unites about eighteen, and the frequency of tuberculous disease in early life are well known. In the lower epiphysis ossification begins before birth, a point of medico-legal importance in deciding whether a newly born child has reached the full period of uterine gestation. From this epiphysis, the level of which is denoted by a line drawn horizontally laterally from the adductor tubercle, and the vascular growing tendon of the adductor magnus — the origin of an exostosis is not uncommon. Displacement of this epiphysis (it unites about twenty) in boj'hood and adolescence is a grave injury from the immediate risk of the popliteal vessels. The mischief is usually done by overextension of the leg, as when this is caught in a rapidly moving carriagewheel; the epiphysis is carried forward in front of the diaphysis, the lower end of which is directed backward, endangering the vessels which are posterior and closely adjacent.
Amputation through the thigh. — This is usuaUj' performed in the lower third, by anterior and posterior flaps, the former being the longer, so as to ensure a scar free from pressure, and circular division of the muscles, vessels, and nerves. The vessels requiring attention are the femoral, which lie at the medial side, and the more posteriorly, the lower the amputation; the descending branch of the lateral circumflex, and the termination of the profunda near the linea aspera. The femoral artery has a marked tendency to retract in the adductor canal. When amputation has to be performed in the upper third of the thigh, the tendency of the ilio-psoas to flex the shortened limb and thus bring the sawn femur against the end of the stump must be remembered, and met by keeping the patient propped up and the stump as horizontal as possible. Some of the structures now divided are shown in fig. 1160.
The buttocks. Bony landmarks. — The finger readily traces the whole outline of the iliac crest. Behind, it terminates in the posterior superior iliac spine, which corresponds in level to the second sacral spine and the centre of the sacroiliac joint. (Holden.)
The third sacral spine marks the lowest limit of the spinal membranes and the cerebrospinal fluid; it also corresponds to the upper border of the great sacro-sciatic notch. The first piece of the coccyx corresponds to the spine of the ischium. (Windle.) Its apex is in the furrow just behind the last piece of the rectum.
The tuberosities of the ischium are readily felt by deep pressure on either side of the anus. In the erect position they are covered by the lower margin of the gluteus maximus. In sitting they are protected by tough skin, fasciae, with coarse fibrous fat, and often by a bursa known, according to the patients in whom it becomes enlarged, as weaver's, coachman's, lighterman's, drayman's bursa. The
dance of sebaceous glands accounts for the frequency of boils here.
Gluteus maximus. — The 'fold of the buttock' neither corresponds accurately to, nor is caused by, the lower margin of this muscle. Thus, medially, it lies below the lower margin of the muscle, as it runs laterally it crosses it, and comes to lie on the muscle. The fold is really due to creasing of the skin adherent here to the coarsely fibro-fatty tissue over the tuber ischii during extension. But in early hip disease, in which flexion of the joint is, with wasting of the muscle, almost unvaryingly present, the fold disappears with well-known rapidity. The prominence of the buttock is mainly due to the gluteus maximus, especially behind and below, and in less degree to the other two glutei in front. Under the lower edge of the gluteus maximus the edge of the sacro-tuberous (great sacro-sciatic) ligament can be felt on deep pressure.
To mark out the upper border of the gluteus maximus a line is drawn from a point on the ihac crest 5 cm. (2 in.) in front of the posterior superior spine, downward and laterally to the back of the great trochanter. The lower border is marked out by a second hne drawn from the side of the coccyx parallel with the former, and ending over the linea aspera at the junction of the upper and middle thirds of the thigh. It must be remembered that only the lower and internal fibres of the muscle are inserted into the gluteal ridge on the femur. The greater part of
Quadratus femoris
it is inserted into the fascia lata and ilio-tibial band and so Into the lateral condyle of the tibia. Weakness of the gluteus maximus and tensor fasciae lata;, with consequent laxity of the iliotibial band, gives rise to abnormal side-to-side passive mobility at the knee-joint in full extension.
Behind the great trochanter, branches of the lateral cutaneous; coming down over the crest, the lateral cutaneous branch of the last thoracic (about in a line with the great trochanter), and behind this the lateral branch of the ilio-hypogastric. Two or three oiTsets of the posterior primary branches of the lumbar nerves cross the hinder part of the ihac crest at the lateral margin of the sacro-spinahs. Two or three twigs from the posterior divisions of the sacral nerves pierce the gluteus maximus close to the coccyx and sacrum, and ramify laterally. Finally, over the lower border of the gluteus maximus, turn upward branches of the posterior cutaneous (small sciatic) and its perineal branch (inferior pudendal), and the fourth sacral nerve.
Sciatic nerve (figs. 1162, 1163). — The point of emergence below the gluteus maximus and the track of this nerve (fourth and fifth lumbar and first three sacral nerves) will be given by a line drawn from a spot a little medial to the middle of the space between the great trochanter and the tuber ischii to the lower part of the back of the thigh, where it usualty divides into the tibial and common peroneal (internal and external popliteal) nerves.
To stretch the nerve, an incision about tliree inches long is made in the line of the nerve, beginning about 3.7 cm. (IJ in.) below the gluteus maximus. The long head of the biceps which covers the nerve trunk and which is descending mediolaterally, is drawn medially. If the nerve is exposed lower down, the interval between the hamstrings is identified and these muscles drawn aside. The perineal branch of the posterior cutaneous (inferior pudenal) perforates the deep fascia about 2.5 cm. (1 in.) in front of the tuber ischii, and turns forward to supply the genitals.
Superior gluteal artery. — If a line be drawn from the posterior superior spine to the apex of the great trochanter, the limb being slightly flexed and rotated medially, the point of emergence of the artery from the upper part of the great sacro-sciatic notch will correspond with the junction of the upper and middle third of this line. (MacCormao.) The gluteal nerve emerges immediately below the artery, and sends branches into the deeper portion.
Inferior gluteal (sciatic) and pudic arteries. — The limb being rotated medially, a line is drawn from the posterior superior spine to the lateral part of the tuber ischii. The point of exit of the above arteries will correspond to the junction of the middle and lower thirds of this line. (MacCormac.)
Perineal portion of sciatic
(From a dissection by W. J. Walsham in St. Bartholomew's Hospital Museum.) The muscular branch of the inferior gluteal (sciatic) artery has been drawn inward over the tuber ischii with the reflected origin of the gluteus maximus muscle.
The patella. — ^The limb being supported in the straight position, and the extensor muscles relaxed, the natural range of mobility laterally of the patella can be estimated. This is interfered with by muscular action in inflammatory conditions.
or by early tuberculous ulceration of the contiguous cartilages. The niunerous longitudinal strise or sulci on the anterior surface of this bone can now also be detected. In these are embedded tendinous bundles of the rectus, so as to give firmer leverage. The fact that these fibres, thus tied down, are liable after stretching and tearing to fold in between the ends of the bone after fracture, is a ready explanation of the difficulty of ensuring bony union here. (Macewen.) The patella is separated from the tibia by a pad of fat and a deep bursa, save at its insertion. Owing to the lowest part of the patella being thus separated from the joint by fat, fracture here does not, necessarily, open the joint.
The bone has the following relation to the femur in different positions: — (1) In extension, the patella rises over the condyles, and in full extension only the lower third of its articular surface rests upon that of the condyles; its upper two-thirds lies upon the bed of fat which covers the
tor magnus are seen
lower and front part of the femur. (2) In extreme flexion, as the prominent anterior surface of the condyles affords leverage to the quadriceps, the patella needs to project very httle; thus, only its upper third is in contact with the femur, its lower two-thu-ds now resting on the pad of fat between it and the tibia. (3) In semiflexion the middle third of the patella rests upon the most prominent part of the condyles. (Humphry.) While the bone now affords the greatest amount of leverage to the quadriceps, it is also submitted to the greatest amount of strain from this muscle, which is acting almost at a right angle to the long axis of the patella. This position may therefore be called the 'area of danger,' as, in a sudden and violent contraction, the patella may be snapped across by muscular action, aided by the resistance given by the condyles, in the same way as a stick is snapped across the knee. The amount of separation of the fragments
in a fracture of the patella is due chiefly to the extent to which the lateral tendinous expansions of the vasti are torn; to a less degree to the haemorrhage from the numerous articular vessels (p. 1452) and synovial effusion. The lower fragment is usually the smaller, and its fractured surface tilted forward; that of the upper one usually looks backward.
The patella, the largest of the sesamoid bones, ossifies by a centre which appears from the third to the fifth year. The process is completed about puberty. The rareness with which necrosis and caries occur here, when the exposed situation of the bone is remembered, is partly
explained by the density of its tissue, especially in front, and the intimate blending of the rectus fibres with its periosteum. When the knee-joint is bent, the trochlear surface of the femur can be made out, with some difficulty, underneath the quadriceps expansion. The upper and lateral angle of this surface forms a useful landmark (Godlee) as a line drawn from it to the adductor tubercle marks the level of the lower epiphysis of the femur.
Dislocation of the patella. — The following anatomical facts account for this taking place much more frequently laterally: — (1) The medial edge of the patella is more prominent, and thus more exposed to injury; it is also well supported, as is seen when, the parts being relaxed, the
fingers are insinuated beneath each border. (2) The pull of the extensor upon the patella, ligamentum patella;, and tibia is somewhat laterally, as the tibia is directed a little laterally to the femur, to meet the medial direction of this bone; the femora being directed medially here, to bring the knee-joints nearer the centre of gravity, and, so, counterbalance their wide separation above at the pelvis. The lateral pull of the quadriceps upon the patella is, in all normal action of the muscle, counteracted by the space taken in the trochlear surface by the lateral condyle, this being wider and creeping up higher, and having a more prominent and thus protective lip. In violent contraction, however, these counteracting points may be overcome.
of the tibia is less so, while on the lateral side this condition is reversed. Descending to the lateral condyle of the tibia, the ilio-tibial band of the fascia lata can be traced. The more distinct lateral condyle is a good landmark for opening the joint in amputation and excision. It also indicates the lower level of the synovial membrane of the knee-joint.
Farther back are the biceps and fibular collateral (long external lateral) Ugament. The gap onjthe medial side between the femoral and tibial condyles is the place for feeling for a displaced medial fibro-oartilage in 'internal derangement' of the knee, and also for 'lipping' in suspected osteoartliritis. On each femoral epicondyle, posteriorly, in a thin subject, can be felt its tubercle, which gives attachment to the collateral ligament. Owing to their being placed behind the ■ centre of the bone, these ligaments become tight in extension. On the upper and posterior
part of the medial femoral epicondyle the adductor tubercle and the vertical tendon of the adductor magnus can be felt during flexion. This bony point is a guide to the lower epiphysis, the ossification of which and its occasional exostosis have been mentioned at p. 1442. The medial aspect of this epicondyle faces practically in the same direction as the head of the femur.
Ligamentum patellae and tuberosity of tibia. — These, in a well-formed leg, should, with the centre of the ankle-joint, be all in the same straight line, a useful point in the adjustment of fractures. (Holden.) Behind the upper half of the ligament is the infrapatellar pad of fat; below, the lower half is separated from the tibia by a deep bursa. The tuberosity (tubercle) of the tibia is on a level with the head of the fibula.
[Prepatellar bursa. — This usually protects the lower part of the patella and upper part of the ligamentum pateUaj. It is liable to be enlarged in those who habitually kneel much, the enlargement being either fluid or solid, and occasionally, in tertiary syphilis. Its close connection with the patella and, at the sides, with the joint itself, is to be remembered in infective inflammations of the bursa. Usually the deep fascia, passing off from the sides of the patella upward to the thigh and downward to the leg, serves to conduct inflammation away from the joint.
Synovial membrane (fig. 1167). — This, the largest of the synovial membranes, forms a short cul-de-sac above the patella, between the quadriceps extensor and the front of the femur, this process reaching about 2.5 cm. (1 in.) above the trochlear surface of the femur. At its highest point this cul-de-sac communicates with an-
Tendon of semitendlnosus
other synovial, bursa-like sac lying between the quadriceps and front of the femur. Thus, synovial membrane will usually be met with 6.2 cm. (2| in.) or more above the trochlear surface or the upper border of the patella when the limb is extended. Flexing the joint draws the membrane down very slightly. During extension, the above pouch is supported by the articularis genu (subcrureus) . Traced downward, the membrane reaches the level of the head of the tibia, being separated in the middle line from the upper part of the ligamentum patellae by fat. It here gives off to the intercondyloid notch the patellar synovial fold (ligamentum mucosum), with its free lateral prolongations, the alar folds (ligamenta alaria). These three so-called ligaments contain fat, the processes not only padding gaps, but also meeting concussions.
The enlargement of these processes, under conditions not yet understood, may certainly be a cause of 'internal derangement,' and simulate a loosened meniscus. But the synovial membrane of this joint is not only the largest: it is also the most complicated, a fact accounting for the grave peril of infective arthritis, and the well-known difficulty of effective drainage and cleansing this joint. Thus 'it passes over the gi-eater portion of the crucial ligaments, but the posterior surface of the posterior crucial, which is connected by means of fibro-areolar tissue to the front of the ligamentum postioum, and the lower portions of both crucial ligaments, where they are united together, of course cannot receive a complete covering from the membrane., (Morris.)
THE KNEE 1449
upper surfaces to their free borders, and then along their under surfaces to the tibia. Between the lateral of these and the upper and back part of the tibia is a prolongation of the synovial membrane to facilitate the play of the popliteus tendon.
Finally, amid the complications of this synovial membrane, its communication with some of the bursae mentioned below, and occasionally with the superior tibio-fibular joint, is to be borne in mind. In effusion the bony prominences are obliterated, and the patella 'floats.' The knee-joint is easUy opened by free lateral incisions lying midway between the margins of the patella and the tuberosities of the condyles, drainage-tubes being passed so as to meet above the patella. The above-mentioned complications of the synovial membrane show that such drainage wiU be often inadequate. By passing a director to the back of the joint and cutting down upon it carefully from the popliteal space, better drainage will be given, but opening the joint by an anterior flap is needed where the above fail, and, even then, cleansing of the numerous deep recesses is obviously difficult.
Structures on the head of the tibia. — From before backward these are: — (1) Transverse ligament. (2) Anterior end of medial meniscus (fibro-cartilage). (3) Lower attachment of anterior crucial. (4) Anterior end of lateral meniscus blending with (3). (5) Posterior extremity of lateral meniscus giving off a strong process to posterior crucial. (6) Posterior extremity of medial meniscus. (7) Posterior crucial ligament. Menisci. — These serve as buffer-bonds and cushions between the contiguous bones. The more frequent displacement of the medial is explained by — (a) its greater fixity, and, therefore, its feeling strains more. Thus, in addition to weaker attachments to the coronary and transverse ligaments, it is connected all along its convex border with the inside of the capsule, and strongly with the tibial collateral ligament. The lateral meniscus, on the other hand, is more weakly attached to the capsule, especially opposite to the popliteus tendon, and has no tie to the fibular collateral ligament. (&) When, in the erect position, the knee-joint is rotated laterally and slightly flexed, a common position, an especial strain is thrown upon the very important tibial collateral ligament, and from the above-mentioned connection, on the medial meniscus also.
Position of knee-joint in disease. — In inflammatory effusion, the position which best accommodates the collection of fluid is one of moderate flexion, the ligaments being now mainly relaxed. Later on, when the ligaments are softened, the hamstrings obstinately displace the leg backward, the tibia being rotated laterally by the biceps. The antero-posterior displacement is always more marked than the lateral. In straightening an anchylosed joint, the resistance of the shortened lateral, crucial, and posterior ligaments, and the facility with which a softened upper epiph.ysial line of tlie tibia may give way, must never be forgotten. Erasion and excision. — The extent and comphcations of the synovial membrane render attention to the following points imperative: — (1) Free exposure of the joint usuaUy by an anterior curved incision, the medial extremity of which must not damage the great saphenous vein. (2) The extent of the pouch under the quadriceps, it may be for 5 cm. (2 in.) above the patella, and the lateral recesses under the vasti. The pouches at the back of the joint are far more difficult to deal with, viz., the partial covering of the posterior crucial ligament, the proximity of the popliteal artery, the pouches in relation to the popUteus, gastrocnemii, and back of the femoral condyles. In erasion, the cartilage and bone, where diseased, are removed with a gouge. Owing to the removal, in addition to the synovial membrane, of the fibro-cartilages, and crucial ligaments, and the damage to lateral and patellar ligaments, there is a most obstinate tendency to flexion afterward. In excision, to avoid injury to the epiphysis, the section of the femur should not pass higher than through the upper third of the trochlear surface. Of the tibia, only 12 mm. (J in.) should be removed.
Genu valgum. — Here the natural angle at which the femur inclines medially to the tibia is increased. As shown by the late v. Mikulicz, this is due to an abnormal growth downward of the medial part of the femoral diaphysis, the epiphysial line being gradually altered from one at right angles to the shaft to one which runs obliquely from without downward and medially. The femur is not only elongated on its medial side, but bent at its lower end, the concavity of the curve being lateral. Other changes have to be remembered. Pes valgus very commonly coexists, and in the tibia there may be a compensatory curve, the concavity being medial, in the lower third, or an analogous alteration in the line of the upper epiphysis may be present, its direction being no longer at a right angle with the shaft, but obhque. In Sir W. Macewen's supra-condyloid osteotomy, a longitudinal incision, about 3.7 cm. (IJ in.) long is made where the following lines meet, viz., one transverse, a finger's breadth above the upper margin of the lateral condyle, and one longitudinal, 1.2 cm. (J in.) in front of the adductor magnus tendon. The bone is divided in front of the genu suprema and above the superior medial articular artery, above the epiphysial line and behind the upward extension of the synovial membrane under the quadriceps.
A. In front. — (1) One between the patella and skin, the bursa prepatellaris subcutanea (fig. 1167); (2) a deeper one between the ligamentum patellse and the upper part of the tibia; (3) between the skin and the lower part of the tuberosity of the tibia. This is not constant.
B. On the medial side. — (1) One between the medial head of the gastrocnemius and medial condyle, often extending between the above muscle and the semi-membranosus. This is the largest of the burs^ about the knee-joint, and, after adult life, usually communicates with the knee-joint. But, owing to the narrow communication, it is rarely possible, when the parts are relaxed by flexion of the joint, to empty the cyst. For its removal a straight incision is made over the most prominent part of the swelling, its neck found by drawing aside the tendons. A ligature is then pushed high up around the neck, and the cyst cut away. (2) One superficial to the tibial (collateral) ligament, between it and the tendon of the sartorius, gracilis, and semi
Fig. 1167. — Vertical Section op the Knee-joint in the Anteeo-posterior Direction. (The synovial bursa usually present above the upper synovial cul-de-sac is not shown.) (The bones are somewhat drawn apart.) (After Braune.)
M. tibialis post
tendinosus (3) One beneath the ligament, between it and the tendon of the semi-membranosus. (4) One between the medial condyle of the tibia and the semi-membranosus. (5) One between the semi-membranosus and semi-tendinosus. Of the above bursae, the first two alone are constant. The second and third are often one bursa prolonged.
C. On the lateral side. — (1) One between the lateral head of the gastrocnemius and the condyle; (2) one superficial to the fibular collateral ligament between it and the biceps tendon; (3) one under the ligament between it and the popliteus tendon; (4) one between the popHteua tendon and the lateral condyle of the femur. This is usually a diverticulum from the synovial membrane.
The following explanations may be given of an inflamed knee-joint usually taking the flexed position: — -(1) By experimental injections, Braune found that the capacity of the synovial sac reaches its maximum with a definite degree of flexion, i. e., at an angle of twenty-five degrees.
Anastomoses around the front and sides of the knee-joint. — The most important of these take the form of three transverse arches. (1) The highest passes through the quadriceps fibres just above the upper edge of the patella. It is formed by a branch from the deep division of the genu suprema (anastomotica magna) and one from the lateral circumflex and superior lateral articular. The middle and lowest arches lie under the ligamentum patellte. (2) The middle arch, formed by branches from the genu suprema and superior medial articular on the medial side, and the inferior lateral articular, on the lateral, runs in the fatty tissue
close to the apex of the patella. (3) The lowest arch lies on the tibia just above its tuberosity, and results from the anastomosis of the recurrent tibial and the inferior medial articular. Seven arteries thus take place in this series of anastomoses.
tendinosus and the biceps.
Popliteal tendons. — When the knee is a little bent and the foot rests on the ground, the following can be made out:— on the lateral aspect, behind the ilio-tibial band, and descending to the prominence on the lateral side of the head of the fibula, is the tendon of the biceps. This
prominence also gives attachment to the fibular collateral ligament, which splits the tendon into two parts. IJehind is the apex (styloid process) from which the posterior part of the fibular collateral ligament arises. Parallel and close to the medial border of the tendon, the peroneal nerve descends, as a rounded cord, to cross the neck of the fibula and enter the peroneus iongus. In tenotomy of the biceps an open incision should be employed to avoid injiary to the nerve and insure the division of any contracted fascial bands. On the medial side the tendons are thus arranged: Nearest to the middle of the popliteal space is the long and more slender tendon of the semi-tendinosus; next, the thicker tendon of the semi-membranosus; this and the gracilis, which comes next, appear as one tendon, but by a little manipulation the finger can be made to sink into the interval between the semi-membranosus, with its thick rounded border laterally and the gracilis medially. The sartorius can easily be thrown into relief on the medial side of the joint by telling the patient to raise the leg extended, the limb being rotated laterally and one leg crosses over the other.
Popliteal vessels. — The artery traverses this space from above downward, appearing beneath the semi-membranosus, a little to the medial side of the middle line, and then passing down in the centre of the space to the interval between the gastrocnemii. Its course corresponds with a line drawn from the medial side of the
hamstrings to the centre of the lower part of the space. The artery bifurcates on the level of a line corresponding to the tuberosity of the tibia. It lies on the popliteal surface of the femur, the oblique popliteal ligament and the popliteus. It is the second of these structures which usually prevents popliteal aneurism and abscess from making their way into the joint.
The popliteal vein, intimately adherent to the artery, lies to the lateral side above, but crosses to its medial side below. The popliteal sheath is also unusually strong. The tibial nerve crosses the artery in the same direction as the vein, by which it is separated from the artery. This nerve is the direct continuation of the sciatic nerve (fig. 1 169), and enters more into the space than its fellow branch. The close relation of the vein and nerve explains the early stiffness of the knee, the pains below, often called 'rheumatic,' and the oedema, in popliteal aneurism; also the pulsation of swelUngs not aneurismal.
The superior articular arteries (fig. 1169) course laterally and medially immediately above the femoral condyles; the way in which they cUng closely to the bone here is one provision to pre vent overstretching of the artery; the inferior ones lie j ust above the head of the fibula and below the medial condyle of the tibia (fig. 1169). The deep part of the genu suprema artery runs in front of the tendon of the adductor magnus; the superficial with the saphenous nerve.
of about 2.5 cm. (1 in.), the vessel is comparatively superficial after division of the fasciae. The nerve is generally seen first, and, with the vein, must be drawn laterally. The needle should be passed from the vein. (B) From the front, at the medial side. The thigh being flexed, abducted, and rotated laterally, a free incision is made parallel and just behind the adductor magnus tendon, commencing at the junction of the middle and lower third of the thigh. The sartorius and the hamstrings are drawn backward, and the adductor magnus forward. Care must be taken of the genu suprema (fig. 1168). The space between the hamstrings and the adductor magnus being carefully opened up, the artery will be found in fatty areolar tissue. The vein and tibial nerve are on the lateral side of the vessel. The needle is passed in lateromedially. The collateral circulation (fig. 1156) depends chiefly on the genu suprema.
The skin. — The proneness of the skin to dermatitis in the lower third of the medial and front aspect of the leg as a result of varicose veins is well known. The close contiguity of the periosteum to the skin here accounts for the difficulty in healing chronic ulcers whose callous base has become fixed to the periosteum, and the frequency with which the upper fragment of a fractured tibia perforates the skin.
Bony landmarks. — From the tuberosity (tubercle) of the tibia descends the anterior border or 'shin. ' This soon becomes sharp, and continues so for its upper two-thirds ; in the lower third it disappears, to be overlaid by the extensor tendons. It is curved somewhat laterally above and medially below. The medial border can also be felt from the medial condyle to the medial malleolus. Between these two borders lies the medial surface, subcutaneous save above, where it is covered by the three tendons of insertion of the gracilis and semi-tendinosus, and, overlying them, that of the sartorius. The tibia is narrowest and weakest at the junction of the middle and lower thirds, the most common site of fracture. Behind the medial malleolus, part of the groove for and the tendon of the tibialis posterior can be felt.
The head of the fibula can be felt distinctly, but the shaft soon becomes buried amongst muscles till about 7.5 cm. (3 in.) above the lateral malleolus, where the bone expands into a large triangular subcutaneous surface.
This lies between the peroneus tertius and the other two peronei. The peroneus longus overlaps the brevis, especially in the upper two-thirds of the leg. In the lower thii'd the brevis tends to become anterior (fig. 1173). Behind the lateral malleolus these tendons descend to the foot in a groove on its posterior border. The shaft of the fibula is placed on a plane posterior to that of the tibia, and curves backward in a du-ection reverse to that of the tibia.
Muscular compartments and prominences. — When the muscles of the leg are thrown into action by dorsi-flexion and plantar flexion of the foot or by standing on the toes, several groups of muscles stand out on the surface, owing to certain compartments, and the origin of certain muscles from, and their separation by, the deep fascia, which knits the surface into corresponding elevations and depressions. The bones and the two peroneal septa divide the leg into four compartments.
These are, medio-laterally : — (1) A medial, corresponding to the medial sm-face of the tibia. (2) An anterior, between the crest of the tibia and the anterior peroneal septum, attached to the antero-lateral border of the fibula, and separating the extensors from the peronei. Its surface-marking would be a line from the front of the head of the fibula to the front of the lateral malleolus. In this anterior compartment lie the extensor muscles and origin of the peroneus tertius, and the anterior tibial vessels and nerves. (3) A lateral or peroneal compartment, lying between the anterior and posterior peroneal septum, the latter being attached to the postero-lateral border of the fibula, and separating the peronei from the calf and deep flexors. This peroneal compartment, a narrow one, contains the two chief peronei and the peroneal (external popUteal) nerve and its three divisions. (4) Much the largest, this, the posterior, lies between the posterior peroneal septum and the medial border of the tibia, and contains the calf and deep flexor muscles, the' posterior tibial vessels and nerves, and the peroneal artery and its posterior branch.
The space between the tibia and fibula in front is mainly occupied by the fleshy belly of the tibialis anterior; lateral to this, and much less prominent, is the narrower extensor digitorum longus; lateral to this, again, are the peronei longus and brevis. Lower down, in an interval between the tibialis and the extensor of the toes, the extensor hallucis, here almost entirely tendinous, comes to the surface. Behind, the prominence of the calf is mainl}' formed by the gastrocnemius. On the patient's rising on tip-toe, the tendo Achillis starts into relief
from about the middle of the leg. Of the two heads of the gastrocnemius, the medial is seen to be the larger. On either side of the tendon, but more distinctly on the lateral side, where it is less overlapped by the gastrocnemius, the soleus comes into view. Its muscular fibres are continued on the deep surface of the tendon to within a short distance of the heel. Between the tendon and the upper part of the os calois is a bursa, oocasionaUy the seat of effusion, as in gonorrhoea.
The bones. — Their relative position and curves have been mentioned (p. 1453). Access. — That to the tibia is easy along the medial aspect. The fibula is best explored by a free incision along the line of the posterior peroneal septum, which lies between the peronei and the muscles at the back (p. 1453). The presence of the superficial peroneal (musculo-cutaneous) nerve perforating the deep fascia in the lower third below and that of the common peroneal (external popliteal) in relation to the neck of the fibula above, must be remembered. Fractures. — When,
Popliteal
Anterior tibial, giving off posterior tibial recurrent and superior fibular before piercing interosseous membrane and anterior tibial afterward
joining posterior peroneal
as is most frequent, the tibia gives way from indirect violence, the fracture is usually at the weakest spot, or the junction of the middle and lower thirds. The line of obliquity is generally marked, and from above downward and forward. The lower fragment, pulled upward by the powerful calf muscles, rides behind the upper, which projects forward under the skin. The fibula, bending more than the tibia, snaps at a higher level. Tenderness on pressure is the best guide here, as it is in suspected fractures of the upper tibia, transverse from direct violence. The most common variety of fracture of the fibula is that called after Pott, complicated with displacement of the foot. Here, from abduction of the foot, a severe strain is thrown upon the deltoid ligament, which gives way; the talus (astragalus) is pressed against the lateral malleolus, and the inferior tibio-fibular ligaments resisting, the fibula yields 5 to 7 cm. (2 to 3 in.) above the anlde, the upper end of the lower fragment being usually displaced toward the tibia. If the deltoid ligament is strong, the strain often tears off the medial malleolus. The medial margin of the foot is turned toward the ground, the lateral raised. The foot is also displaced backward. On the medial side of the ankle there is a marked projection of the lower end of the tibia; higher
up, on the lateral side, a depression where the fibula is broken. The need of replacing the^foot and the weight-bearing talus (astragalus) accurately, the fact that the ankle-joint is opened and the numerous tendons iikety to be matted are the chief points to bear in mind. In Dupuytren^s fracture there is not only fracture of the lower end of the fibula, but the inferior tibio-fibular ligaments are now torn. The foot is displaced upward and laterally, together with the lower
end of the fibula. Epiphyses.—The upper one of the tibia appears shortly before birth and includes the condyle and tuberosity. It does not fuse with the shaft till the age of twenty or later. This fact and the powerful strain of the rectus on this epiphysis explain the obscure pain sometimes complained of in young adults much given to atliletics, over the tibial tuberosity. The lower epiphysis, including the medial malleolus, appears in the second and joins about the eighteenth year. Separation here is not very uncommon up to puberty. In osteotomy of the
tibia, simple or cuneiform, when the curve is antero-posterior as well as lateral, the close vicinity of the tibiaUs anterior tendon to the lateral border of the crest must be remembered, and when the fibula does not yield to careful force, it, also, must be divided, or damage may be done to the superior and inferior tibio-fibular Ugaments, or to the epiphyses of the bones.
(figs. 1158, 1172), having passed from the arch on the dorsum over the medial malleolusjf'runs up close to the medial border of the tibia, where it is to be avoided *in ligature of the posterior tibial, to the back of the medial condyle; here this vessel is to be remembered in operations on the knee-joint; then upward along the thigh, over the roof of the adductor (Hunter's) canal, to the fossa ovalis (saphe-
chieily in the upper part.
rpntJi'nf'?hrfh^°ul^''?u'' °''-f^^ ^? T^^'^'^ thrombosis is most Hkely to occm-, reaches from the h»?„ ,f fi I ^u *° t'^l^i'ldle of the leg. (Bemiett.) The saphenous nerve joins the vein below the knee, having been under the sartorius above this point (fig. 1159 and 1160) The
surface-marking of the upper part of the vein is a line drawn from the posterior border of the sartorius or the adductor tubercle to the lower part of the fossa ovalis. The small saphenous vein passes behind the lateral malleolus, runs upward over the middle of the calf, and joins the popliteal by perforating the deep fascia in the lower part of the popliteal space. This vein is accompained by the medial sural cutaneous (external saphenous) nerve throughout its course.
The popliteal artery bifurcates at the lower border of the popliteus, about on a level with the tuberosity of the tibia. About 5 cm. (2 in.) lower down the peroneal artery comes off from the posterior tibial (fig. 1173).
The course of the posterior tibial corresponds with a line drawn from the centre of the lower part of the popliteal space to a point midway between the tip of the medial malleolus and the medial edge of the calcaneus.
In the lower third, the artery becomes more superficial, passing from beneath the calf muscles, lying between the tendo Achillis and medial border of the tibia, and covered only by the skin, deep fascia, and, lower down, by the laciniate (internal annular) ligament. It is here, in its close relation to the tendons of the tibialis posterior and flexor digitorum longiis, that it is liable to be injured in the older methods of tenotomy. The nerve is medial above, lateral below (fig. 1173).
Posterior tibial vessesls and tibial nerve
medial_border of the tibia, to avoid the trunk of the great saphenous. The deep fascia being freely opened, the medial head of the gastrocnemius is drawn backward. The tibial attachment of the soleus, thus exposed, is out through carefully, so as to allow of identification of its central membranous tendon, which must not be confused with the deep intermuscular septum over the flexor. Any sural vessels are now tied. The above-mentioned special septum is next made out, passing between the bones (vertical Une descending from oblique hne of tibia and oblique line of fibula). On division of this septum the nerve usually comes into view, the artery lying more laterally. The needle is passed from the nerve; the vense comitantes may be included. The muscles should now be fully relaxed by flexion of knee and plantar flexion of foot. The ligature will be placed below the peroneal artery.
The course of the anterior tibial artery corresponds with a line drawn from a point midway between the lateral condyle of the head of the tibia and the head of the fibula to one on the centre of the ankle-joint.
This line corresponds to the lateral border of the tibialis anterior and the interval between it and the extensor digitorum longus (figs. 1170 and 1171). This is shown when the first of these muscles is thrown into action. The accompanying nerve is in front in the middle third of the leg, lateral above and below.
Ligature of the anterior tibial artery at the junction of the upper and middle thirds of the leg. The limb being flexed and rotated medially, an incision is made, 7.5 to 10 cm. (3 to 4 in.) long, in the line of the artery, distant 2.5 cm. (1 in.) or more (according to the size of the leg) from the crest, and beginning about 5 cm. (2 in.) below the head of the tibia. If, on exposure of the deep fascia, the intermuscular septum between the tibialis and long extensor of the toes
is not well defined, the fascia must be freely slit up in the line of the artery, and the sulcus felt for. A small muscular artery may lead down to the trunk. The foot is now dorsiflexed and the artery sought for deep on the interosseous membrane. The nerve should be drawn to the outer side. The venas comitantes may be included in the ligature.
In senile gangrene the liabiUty of the tibial arteries to disease and consequent thrombosis and interference with the collateral cu-eulation accounts both for the extension of the disease and the difficulty in detecting pulsation.
The peroneal artery, given off from the posterior tibial about an inch below the popliteus, or two inches below the head of the fibula, runs deeply along the medial border of this bone, covered by the flexor hallucis longus, the nerve to which accompanies the vessel.
It gives off the anterior peroneal, through the interosseous membrane, to the front of the lateral malleolus about an inch above the level of the ankle-joint. Its continuation, as the posterior peroneal, runs behind the malleolus, to join the anastomosis about the ankle-joint.
As a general rule, in amputation 2.5 cm. (1 in.) below the head of the fibula, only one main artery — the popliteal — is divided. In amputations 5 cm. (2 in.) below the head of the fibula, two main arteries — the anterior and posterior tibials — are divided. In amputations 7.5 cm. (3 in.) below the head, three main arteries — the two tibials and the peroneal — are divided. (Holden.)
In an amputation through the middle of the leg, the anterior tibial artery would be found cut on the interosseous membrane between the tibialis anterior and the extensor hallucis longus, the deep peroneal nerve here lying in front of the vessel. The posterior tibial would be between the superficial and deep muscles at the back of the leg lying on the tibialis posterior, its nerve being to the lateral side. The peroneal would be close to the fibula in the flexor hallucis longus.
The superficial peroneal (musculo-cutaneous) nerve, having passed through the peroneus longus and then between the peroneus longus and peroneus brevis, perforates the deep fascia in the lower third of the leg in the line of the septum between the peronei and extensors. Directly after, it divides into its two terminal branches.
Amputation of the leg. — To give one instance only, amputation 'at the seat of election, or a hand's-breadth below the knee-joint, will be alluded to. Lateral skin-flaps and circular division of the muscles give an excellent result in hospital practice where the various conditions which call for such a step are usually met with. The above name was given because the pressure of the body is well carried on the prominences about the knee-joint, especially the tuberosity of the tibia, when the patient walks with the knee flexed on a 'bucket' artificial limb. Thus the scar, being central, is here not of importance. Two broadly oval lateral flaps of skin and fasciae are raised, and the remaining soft parts severed down to the bones with circular sweeps of the knife. In sawing the bone, the smaller size of the fibula and its position behind the tibia must be remembered. It is well, in order to ensure complete division of the fibula first, to roll the limb well over on its medial side, and place the saw well down on the lateral side. The parts cut thi'ough are shown in fig. 1174.
Bony landmarks. — The following are the differences between the two malleoli : The medial is the more prominent, shorter, and is placed more anteriorly than the lateral, being a little in front of the centre of the joint. The lateral descends lower by about 1.2 cm. (| in.), and thus securely locks in the joint on this side; it is opposite to the centre of the ankle-joint, being placed about 1.2 cm. (| in.) behind its fellow.
Owing to the lateral malleolus descending lower than the medial, in Syme's and Pirogoff's amputations the plantar incision should run between the tip of the lateral malleolus and a point 1.2 cm. (J in.) below that of the medial one. When a fracture is set, or a dislocation adjusted, the medial edge of the patella, the medial malleolus, and the medial side of the great toe are useful landmarks and should be in the same vertical plane, regard being paid at the same time to the corresponding points in the opposite limb. (Holden.)
On the posterior aspect of the medial malleolus is a groove for the tibialis posterior and flexor digitorum longus, the first named being next the bone. The tip and borders of the process give attachment to the deltoid ligament. The anterior border and tip of the lateral malleolus give attachment to the anterior talo-fibular and calcaneo-fibular ligaments respectively, the posterior talo-fibular arising from a pit behind and below the articular facet. The posterior border is grooved for the two peronei. The line of the ankle-joint corresponds to one about 1.2 cm. (I in.) below the tip of the medial malleolus drawn across the anterior aspect.
Effusion or tuberculous thickening shows itself first in front, between the medial malleolus and tibialis anterior and between the peroneus tertius and lateral malleolus and then behind, where it fills up the hollow between the tendo Achillis and the two malleoli. Owing to the thinness of the transverse crural (anterior) ligament, the extensor sheaths are easOy affected in neglected tuberculous disease. Owing to the way in which the joint is locked in, it is not easy to open and drain an infected ankle-joint satisfactorily. Removal of a portion of the lateral
tube and good drainage if the foot is so slung as to keep its lateral aspect dependent.
Tendons. — (A) In front of ankle. — ^Latero-medially are — (1) The tibialis anterior, the largest and most medial. This tendon appears in the lower third of the leg, lying just under the deep fascia, close to the tibia; then, crossing over the
lower end of this and the ankle-joint, it passes over the medial side of the tarsus, to be inserted into the medial and lower part of the first cuneiform and the adjacent part of the first metatarsal. (2) The extensor hallucis longus. This tendon, concealed above, appears low down in a line just lateral to the last, and then, crossing over the termination of the anterior tibial vessels and nerves (to which its muscular part lies lateral), it descends along the medial part of the dorsum to be inserted into the base of the last phalanx of the great toe. (3) and (4) The extensor digitorum longus and peroneus tertius enter a common sheath in the transverse crural ligament. The former then divides into four tendons, which
(B) Behind. — The tendo Achillis, the thickest of all tendons, begins near the middle of the leg, in the junction of the tendons of the gastrocnemii and, a little lower, (p. 1453) the soleus. Very broad at its commencement, it gradually narrows and becomes very thick. About 3 . 7 cm. (1| in.) from the heel, or about the level of the medial malleolus, is its narrowest point. After this it again expands sHghtly, to be inserted into the middle of the back part of the calcaneus. The long tendon of the plantaris runs along its medial side, to blend with it or to be attached to the calcaneus. On either side of the tendo Achillis are well-marked
furrows below. Along the medial, the tendon of the tibialis posterior and the posterior tibial vessels and nerve come nearer the surface. Along the lateral, the small saphenous vein (more superficially) ascends from behind the lateral malleolus.
(C) On the medial side. — The tendon of the tibialis posterior, which has previously crossed from the interspace between the bones of the leg to the medial side, lies behind the inner edge of the tibia above the medial malleolus, then behind this, being here under the flexor digitorum longus, the two tendons having become superficial on the medial side of the ten do Achillis. It then passes forward over the deltoid and under the laciniate (internal annular) ligament between the medial malleolus and the sustentaculum tali, and then below and close to the plantar cal-
caneo-navicular ligament {vide infra) , and so to its insertion, by numerous slips, into the tarsus and metatarsus, especially the tuberosity of the navicular. The tendon of the flexor hailucis longus cannot be felt. Having passed medially from the fibula, it crosses the lower end of the tibia in a separate furrow, then grooves the backof the talus, and passes under the sustentaculum tali on its way to its insertion.
The arrangement of the structures at the medial ankle from above downward, and mediolaterally, is as follows (fig. 1177): — tibialis posterior, flexor digitorum longus, companion vein, posterior tibial artery, companion vein, tibial nerve, flexor hailucis longus. The tibiales posterior and anterior turn the sole mediaUy, antagonising the peronei. They also bear a large
share in maintaining the longitudinal arch of the foot. The flexors not only act upon the toes, but aid the calf muscles in straightening the foot upon the leg in walking or standing upon tiptoe; hence the value of educating them in cases of flat-foot.
(D) Tendons on the lateral aspect. — The tendons of the two peronei, which arise from the fibula between the extensor digitorum longus and flexor hallucis longus, pass behind the lateral malleolus, the brevis being nearer to the bone (fig. 1177). They then pass forward over the lateral surface of the calcaneus, separated by the peroneal tubercle when present, and diverge.
The brevis — the upper one — passes to the projection at the base of the fifth metatarsal; the longus, lying below the brevis on the calcaneus, winds round the lateral border of the foot, grooving the lateral border and under surface of the cuboid. Finally, crossing the sole obliquely forward and medially, it is inserted into the adjacent parts of the first cuneiform and the back part and under surface of the first metatarsal. While in connection with the under surface of the cuboid, this tendon is covered in by a sheath from the long plantar ligament, and often contains a sesamoid bone. The two peronei evert the foot, as is seen in talipes valgus and in fracture of the lower end of the fibula; the peroneus longus aids in the support of the arch of the foot (p. 1466), and, by keeping the great toe on the ground, is important in the third stage of walking, skating, etc.
peronei in place, and surrounds them behind the fibula in one sheath with a single synovial sac, which extends upward into the leg for 3 . 7 cm. (1| in.), and sends two processes into the two sheaths in which the tendons lie on the calcaneus. Farther on, while in relation with the cuboid, the peroneus longus has a second synovial sheath.
(B) Medial. — This, the laciniate ligament, crosses from the medial malleolus to the medial surface of the calcaneus. Beneath it are the following canals : — (1) For the tibialis posterior. This tendon-sheath is lined by a sj^novial membrane extending from a point 3.7 cm. (1| in.) above the malleolus to the navicular. (2) For the flexor digitorum longus. The synovial sheath of this tendon is separate from that of the closely contiguous tibialis posterior. It extends upward into the leg about as high as the sheath just given. It reaches down into the sole of the foot; but where the tendon subdivides to enter the thecse, each of these is lined by a separate synovial sheath. Next comes (3) a wide space for the posterior tibial vessels and nerve; and, lastly, (4) a canal, like the other two, with a separate synovial sheath, for the tendon of the flexor hallucis longus. The lower margin of this annular ligament gives an attachment to the abductor hallucis and blends with the plantar fascia. The medial calcaneal vessels and nerve perforate the ligament.
(C) Anterior annular ligament. — This is a double structure. (1) Upper (transverse crural ligament), above the level of the ankle-joint, and tying the tendons down to the lower third of the leg, passes transversely between the anterior crest of the tibia and fibula. Here is one sheath only, with a synovial membrane for the tibialis anterior. (2) Lower, over the ankle-joint. This band, the cruciate ligament, is arranged like the letter -<, placed thus. It is attached by its root to the calcaneus, and by its bifurcations to the medial malleolus and plantar fascia.
This arrangement of the branches of this ligament is not constant. In this, the lower annular ligament, there are usually three sheaths with separate synovial membranes — the most medial (the strongest in each) for the tibialis anterior, the next for the extensor halluois longus, and the third common to the extensor communis and peroneus tertius. The extensor digitorum brevis has a partial origin from this ligament.
Points in tenotomy and guides to the tendons. — The tendo Achillis should be divided about 3.7 cm. (If in.) above its insertion, its narrowest point, which is about on a level with the medial malleolus. The knife should be introduced on the medial side and close to the tendon, so as to avoid the posterior tibial artery (fig. 1178).
The tibialis anterior may be divided about 25 mm. (1 in.) above its insertion into the first cuneiform, a point which is below the level of its synovial sheath. The tendon has here the dorsalis pedis on its lateral side, but separated by the tendon of the extensor hallucis longus. The knife is introduced on this side.
The tibialis posterior. — The usual rule for dividing this tendon is to take a spot 5 cm. (2 in.) above the medial malleolus, and as accurately as possible midway between the anterior and medial borders of the leg. This point will give the medial margin of the tibia, in close apposition to which the tendon is lying, and is a point at which the tendon is rather farther from the artery than it is below, and is also above the commencement of its synovial sheath. A sharp-pointed knife is used first to open the sheath freely, and then a blunt-pointed one to divide the tendon. The flexor digitorum longus is usually cut at the same time.
Owing to the risk of injury to the posterior tibial vessels, the difficulty of ensuring division of the tendons, the following open method is, nowadays, superior, being more certain, and admitting of division of ligaments, e. g., talo-navicular and anterior part of deltoid (syndesmotomy of Parker), which are always contracted in advanced talipes equino-varus. A V-shaped flap with its apex over the first metatarsal bone, and its two limbs starting, the lower below the margin of the plantar fascia on a line with the medial malleolus, the upper from a point over the head of the talus, is turned backward. The plantar fascia is divided, the tibiaUs anterior is found, near its insertion, under the upper hp of the wound, the tibialis posterior and the flexor digitorum longus in the lower, the former close to the navicular. If necessary, the calcaneoand talo-navicular and anterior part of the deltoid ligaments can be divided also.
Peronei. — The peronei longus and brevis may be divided 5 cm. (2 in.) above the lateral malleolus, so as to be above the level of their synovial sheath. The knife should be inserted very close to the bone, so as to pass between the fibula and the tendons. Division below the ateral malleolus by a small flap is easier.
(1) Medial tuberosity of the calcaneus; (2) medial malleolus; (3) 2.5 cm. (1 in.) below the malleolus, the sustentaculum tali; (4) about 2.5 cm. (1 in.) in front of the medial malleolus, and a little lower, is the tuberosity of the navicular, the medial guide in Chopart's amputation, the gap between it and the sustentaculum being filled by the calcaneo-navicular ligament and the tendon of the tibialis posterior, in which there is often a sesamoid bone; (5) the first cuneiform; (6) the base of the first metatarsal; and (7) the head of the same bone, with its sesamoid bones below. (Holden).
(B) Along the lateral aspect are : — (1) The lateral tuberosity of the calcaneus; (2) the lateral malleolus; (3) the peroneal tubercle of the calcaneus (when present), 2.5 cm. (1 in.) below the malleolus, with the long peroneal tendon below it, and the short one above; (4) the projection of the anterior end of the calcaneus, and the calcaneo-cuboid joint, midway between the tip of the lateral malleolus and the base of the fifth metatarsal bone; (5) the base of the fifth metatarsal bone; (6) the head of this bone. The greater process of the calcaneus and the muscular origin of the short extensor lie between the peroneus brevis and tertius.
Levels of joints and lines of operations. — The line of the ankle-joint has been given at p. 1459. That of the talo-calcaneal joint — the limited lateral movements of the foot take place here and at the medio-tarsal joint — corresponds, on the lateral side, to a point a little in front of the lateral malleolus and midway between it and the peroneal tubercle; on the medial
side, to one just above the sustentaculum tali. In Syme's amputation through the ankle-joint, the incision starts from the tip of the lateral malleolus, and is then carried, pointing a little backward toward the heel, across the sole to a point 1.2 em. (i in.) below the medial malleolus. The chief supply to the heel-flap is from the medial calcaneal. Care should be taken to divide the posterior tibial below its bifurcation and not to prick this vessel afterward.
In Pirogoff's amputation the incision begins and ends at the same points, but is carried straight across the sole. In each amputation the extremities of the above incision are joined by one going directly across the ankle-joint, which lies about 1.2 cm. (5 in.) above the tip of the internal malleolus.
In Chopart's medio-tarsal amputation, which passes between the talus and the navicular on the medial side, and the calcaneus and the cuboid on the lateral, the line of the joints to be opened would be one drawn across the dorsum from a point just behind the tuberosity of the navicular to a point corresponding to the calcaneo-cuboid joint, just midway between the tip of the lateral malleolus and the base of the fifth metatarsal bone. The convexity of the plantar flap should reach to a point 2.5 cm. (1 in.) behind the heads of the metatarsal bones. Owing to the tendency of the unbalanced action of the calf muscles to tilt up the calcaneus and thus thi'ow the scar down into the line of pressure, the powerful tibialis anterior tendon and those of the extensors should be carefully stitched into the tissues of the sole flap.
In Lisfranc's, or Hey's, or the tarso -metatarsal amputation, the bases of the fifth and first metatarsals must be defined. The first of these can always be detected, even in a stout 'or swollen foot; on the medial side the joint between the first cuneiform and the first metatarsal
Fig. 1179. — Vektical Section through the Cuneiform and Cuboid Bones. (One-half.) In opening the joint between the second metatarsal and the middle cuneiform, its position (the base of the former bone projecting upward on to a level 6 or 8 mm. (| or 5 in.) above the others), and the way in which it is locked in between its fellows and the cuneiform bones, must be remembered. The convexity of the plantar flap here reaches the heads of the metatarsal bones.
In marking out the flaps for the amputation of the great toe, the large size of the head of the first metatarsal, and the importance of leaving this so as not to diminish its supporting power and the treading width of the foot, and thus of marking out flaps sufficiently long and large, must be borne in mind. The dorsal incision should begin 3.7 cm. (1| in.) above the web. The line of the joint is a httle distal to the centre of the ball of the toe (fig. 1181). The sesamoid bones should be left, so as not to endanger the vitaUty of the flaps. In amputation of the other toes, the line of their metatarso-phalangeal joints lies a full inch above the web.
Bursse and synovial membranes. — The synovial sheath of the extensor hallucis longus extends from the front of the ankle, over the instep, as far as the metatarsal bone of the great toe. There is generally a bursa over the instep, above, or it may be below, the tendon.
There is often an irregular bursa between the tendons of the extensor digitorum longus and the projecting end of the talus over which the tendons play. There is much friction here. It is well to be aware that this bursa sometimes communicates with the joint of the head of the talus. (Holden.) There is a deep synovial bursa between the tendo Achillis and the calcaneus. Numerous other bursie may appear over any of the bony points in the foot, especially when they are rendered over-prominent by morbid conditions.
bones; (2) talo-calcaneo-navicular, common to these bones and the navicular; (3) between the calcaneus and the cuboid; (4) between the cuboid and the lateral two metatarsals; (5) between the first cuneiform and the first metatarsal; (6) a comphcated and extensive one, which branches out between the navicular and cuneiform bones; between the cuneiforms; between the third cuneiform and the cuboid ; between the second and third cuneiform and the second and third metatarsal bones; and between the second and third and the third and fourth metatarsal bones.
upper part of the first interosseous space.
On its medial side is the tendon of the extensor hallucis longus ; on its lateral, the most medial tendon of the extensor digitorum longus. It is crossed by the most medial tendon of the extensor brevis. The origin of this muscle should be noted on the lateral and fore part of the calcaneus.
Cutaneous nerves (fig. 1182). — The sites of these, numerous on the dorsum of the foot, are as follows: — The superficial peroneal (musculo -cutaneous) nerve, having perforated the fascia in the lower third of the leg, divides into two chief branches, medial and lateral, which supply all the toes save the lateral part of the little, and the adjacent sides of the first and second. The deep peroneal becomes cutaneous in the first space, and is distributed to the contiguous sides of the above-
mentioned toes. The sural nerve runs with the small saphenous vein below the malleolus, and supphes all the lateral border of the foot and the lateral side of the little toe. The saphenous nerve, coursing with the great saphenous vein in front of the medial malleolus, supplies the medial border of the foot as far as the middle of the instep. The cutaneous nerves to the sole (from the medial calcaneal, medial, and lateral plantar) are shown in fig. 1180.
Plantar arteries. — The line of the medial would be one drawn from the bifurcation of the posterior tibial, or about midway between the tip of the medial malleolus and the medial border of the heel, to the middle of the plantar surface of the great toe. The course of the lateral plantar runs in a line drawn from the bifurcation, first obhquely across the foot to a point a little medial to the medial side of the base of the fifth metatarsal, and thence obliquely across the foot till it reaches the first space and joins with a communicating branch from the dorsal artery. It thus crosses the foot twice. In the first part, it is more superficial, in the second
Tarsal bones. — The chief surgical points about these is the frequency with which they are diseased and their changes in taHpes. Frequency of disease. — This is explained, chiefly, by their delicate structure and the fact that on the aspect in which they are most exposed to injury the soft parts are scanty. Disease once started, often by slight injury, finds in the terminal circulation of the parts, and the frequent want of rest, other contributing causes. The numerous and complicated synovial membranes mentioned above explain the extension of the disease. The calcaneus is the only bone in which mischief is likely to remain limited. The presence of an epiphysis to this bone appearing about the age of ten and joining at puberty is to be remembered as a starting-point of disease here. Talipes. — To take one instance, a case of talipes equino-varus, of congenital origin and confirmed degree, the following are the chief structural changes which should have been obviated and now have to be met, given briefly. Calcaneus. — This is elevated posteriorly, and rotated so that its long axis is du"ected obliquely medially. Talus. — The inclination of the neck medially is much increased, and the whole bone protruded from the ankle-joint. According to some, the neck is increased in length. Navicular. — This is displaced medially so that it articulates with the medial side of the head of the talus, and its tuberosity may form a facet on the medial malleolus. Cuboid. — The dorsal surface of this is displaced downward, and bears much of the pressure in wall^ing. Tendons. — Those chiefly shortened are the tendo AchiUis and those of the tibials and flexor digitorum longus. The tendo AchiUis is displaced medially. Ligaments. — Those on the lateral side are stretched, those on the medial, especially the anterior part of the deltoid, the dorsal talo-navicular and the plantar calcaneo-navicular ligaments are shortened. The plantar fascia is also shortened, together with the abductor hallucis, which arises from it.
(A) Longitudinal arch (fig. 1181). — This is by far the most important. Extent : From the heel to the heads of the metatarsal bones. The toes do not add much to the strength and elasticity of the foot. (Humphry.) They enlarge its area and adapt it to inequalities of the ground, are useful in climbing, and in giving an impulse to the step before the foot is taken from the ground, in the third stage of walking. Two pillars. — The late Professor Humphry laid stress on the important differences between these two: — (1) Posterior pillar: This consists of the calcaneus and hinder part of the talus, viz., only two bones in order to secure solidity, and to enable the calf-muscles to act directly upon the heel, without any of that loss of power which would be brought about by many moving joint-surfaces. (2) Anterior pillar: Here there are many bones and joints to provide (a) elastic springiness, and (6) width. This anterior pillar may again be divided into two: (a) A medial pillar, very elastic, consisting of the talus, navicular, three cuneiforms, and three medial metatarsals. (6) A lateral, formed by the cuboids and two lateral metatarsals. This is stronger and less elastic, and tends to buttress up the medial pillar. Keystone : This is represented by the summit of the trochlear surface of the talus.
It differs from the keystones in ordinary arches in the following important particulars (Humphry) : (a) in not being wedge-shaped; (6) in not being so placed as to support and receive support from the two halves of the arch: in front the talus does fulfil this condition by fitting into the navicular; behind, it overlaps the calcaneus without at all supporting it; (c) this arch and the support of its keystone largely depend on ligaments and tendons; (d) it is a mobile keystone : to give it chances of shifting its pressure, and so obtaining rest, its equilibrium is not always maintained in one position.
(B) Transverse arch (fig. 1179). — This is best marked about the centre of the foot, at the instep, along the tarso-metatarsal joints. This, as well as the longitudinal arch, yields in walking, and so gives elasticity and spring.
Uses of the arches. — (1) They give combined elasticity and strength to the tread. Thus they give firmness, free quickness, and dignity, both in standing and walking, instead of what we see in their absence, viz., the lameness of an artificial limb, and the shufHing or hobbhng which goes with tight boots, deformed toes, flat-foot, bunions, corns, etc.; (2) they protect the plantar vessels, nerves, and muscles; (3) they add to man's height; (4) they make his gait a perfect combination of plantigrade and digitigrade, as is seen in man's walking, when he uses first the heel, then all the foot, and then the toes. (Hiimphry.)
Maintenance of the arch. — (1) Plantar fascia. — -This is (a) a binding tie between the pillars of the longitudinal arch; (6) it protects the structures beneath; (c) it is a self-regulating ligament and protection. Thus, having a quantity of muscular tissue attached to its upper and back part, is constantly responds by the contraction of this, to the amount of any pressure made upon the foot. (2) Plantar calcaneo-navicular ligament. — This is a thick tie-plate of fibro-cartilaginous tissue, partly elastic, hence called the 'spring-ligament,' attached to the anterior margin of the sustentaculum tali and under surface of navicular. It is thickest at its medial side, where it blends with the anterior part of the deltoid ligament, and below, where the tibialis posterior, passing into the sole, is in contact with the ligament and gives much support to the head of the talus and the navicular, while it assists the power and spring of this ligament {vide infra). The dropping of the talus and navicular and their projection on the medial side in flat-foot are largely due to the giving way of the above ligament. (3) Calcaneo-cuboid ligaments, (o) Long; (b) short. — 'These ligaments are the main support of the lateral, firm, and less elastic part of the longitudinal arch. (4) Tibialis posterior. — The reason of this muscle having so many insertions below is to brace together the tarsal bones, and to prevent their separation when, in treading, the elastic anterior pillar tends to widen out. Of these numerous offsets, that to the navicular is the most important. Thus it strengthens the calcaneo-navicular ligament by blending with it, and thus supports the arch at a trying time. By coming into action when the heel is raised, this tendon helps the calcaneo-navicular ligament to support the head of the talus, and to maintain the arch of the foot when the weight of the body is thrown forward on^to the instep. In other words, the tibialis posterior comes into play just when the heaviest of its duties is devolving upon this ligament, viz., when the heel is being raised, and the body-weight is being thrown over the instep on to the opposite foot. (5) Peroneus longus. — This raises the lateral pillar, and steadies the lateral side of the arch. Further, by its strong process attached to the first metatarsal bone, it keeps the great toe strapped down firmly against the ground; thus, keeping down the anterior pillar of the longitudinal arch, it aids the firmness of the tread. (Humphry.) (6) Tibialis anterior. — This braces up the keystone of the arch. Thus, by keeping up the first cuneiform, it maintains the navicular, and so indirectly the talus in situ.
Fig. 1172 will remind the reader of the arrangement of the superficial lymphatics of the lower extremity. These follow chiefly the saphenous veins, and enter the inguinal nodes, except those from the lateral aspect of the heel which
the inguinal glands.
The deep lymphatics of the lower limb, comparatively few in number, follow the course of the deeper vessels. After passing through some four or five glands deeply placed about the popliteal vessels (these glands also receive the lymphatics along the small saphenous vein), the lymph is carried up by lymphatics along the femoral artery to the deep inguinal nodes; one very often occupies the femoral canal.
Paralysis of the nerves of the lower extremity. — Ttie student sliould take this opportunity of considering from the surgical anatomy the results of paralysis of the nerve chiefly affected, viz., the great sciatic and its branches. Sciatic: The limb hangs flail-like, much in the position of one affected with advanced infantile paralysis. In addition to the results of paralysis of its two divisions, flexion at the knee will be lost, owing to paralysis of the hamstrings. Peroneal (external popliteal) nerve: The extensors and psronei being paralysed the foot drops, it cannot be dorsiflexed at the ankle nor abducted at the medio-tarsal joint. Adduction at the latter joint is impaired owing to paralysis of the tibialis anterior. The arch of the foot is largely lost owing to paralj'sis of the peroneus longus. Slight extension of the two distal phalanges of the four lateral toes is still possible by means of the interossei. Sensation is impaired over the distribution of the medial sural cutaneous deep, and superficial peroneal nerves. Tibial (internal popliteal) nerve: Here the calf muscles, the flexors, and the muscles of the' sole of the foot are paralysed. The ankle cannot be plantar-flexed.
meral artery, 573
of thoraco-acromial artery, 571 of transverse scapular artery, 565 (scapular) e.xtremity of clavicle, 141 Aoromio-clavicular joint, 251, 1363 Acromion angle, 144
association, of cerebral cortex, 894 auditory (cochlear), of cerebral cortex, 893 of Broca (area parolfactoria), 858, 865 cortical, of speech, 894
of upper limb, 1022
of distribution of spinal nerves, 970 functional, of cerebral cortex, 893 Areola of mammary gland, 1300, 1304
septi nasi, 541
Arterial supply of bones and joints (see corresponding bone or articulation), system, morphogenesis and variations of, ArterioliE rectae of kidney, 1247 Artery (see also "Blood-vessels"). Artery (ies), 527
Arthrodial diarthroses, 212
Articular arteries of knee-joint, 622, 1452 branches of auriculo-temporal nerve, 941 of common peroneal (external popliteal)
of profunda artery, 621
of tibial (internal popliteal) nerve, 1010 of transverse scapular artery, 565 capsules of acromio-olavicular joint, 251 of articulation of atlas with occiput, 218 of atlanto-dental joint, 222
disc of aoromio-olavicular joint, 251 of inferior radio-ulnar joint, 264 of mandibular articulation, 216 of sterno-costo-clavicular joint, 249 furrows of skin, 1284
in female (sphincter vaginae), 451 Bulbo-urethral (Cowper's) glands, 1265 Bulbous corpuscles (end-bulbs of Krause),
Calcaneal pillar, 205
Caleanean branches, lateral, of sural nerve, of peroneal artery, lateral, 626 of posterior tibial artery, medial, 626
Calcaneo-plantar cutaneous nerves, 1010 Calcaneus (os calcis), 191, 195 Calcar avis (hippocampus minor), 864, 868
of mandibular articulation, 215 of medial tarso-metatarsal joint, 308 of metacarpo-phalangeal joint of thumb,
transverse, 565
branches of uterine artery, 610 chains of lymphatic nodes, deep, 714 enlargement of spinal cord, 772 fascia, external, 347
Cloaca, 1179, 1253, 1278
Clunial (gluteal) branches, inferior, of posterior femoral cutaneous nerve, 1007 nerve, inferior medial (perforating cutaneous), 1007
veins, 658
Connecting fibro-cartilage, 211 Connections, central, of cranial nerves, 818 (for individual nerves, see "Central connections"),
branches of anterior ethmoidal artery, 554 of intercostal arteries, 589, 590 (communicans fibularis) of common peroneal nerve, 1013
of superior epigastric artery, 567 (medial sural cutaneous or tibial communicating) of tibial nerve, 1010 of ulnar nerve, 990
Deltoid branch of profunda artery, 576 of thoraco-acromial artery, 571 (internal lateral) ligament of anklejoint, 298
Descending aorta, 586
brandies of cervical plexus, 978 of lateral circumflex artery, 543 (princeps cervicis) of occipital artery, 543 of spheno-palatine (Meckel's) ganglion,
joint, 251
of inferior radio-ulnar articulation, 264 of mandibular articulation, 216 of the sterno-costo-clavicular joint, 249
portion of external cervical fascia, 347 Infra-omental region of peritoneum, 1372 Infra-orbital artery, 549, 1075
of ethmoid, 83
in middle nasal meatus. 111, 1205 of tuba? uterinte (Fallopian tubes), 1270 Inguinal abdominal (internal abdominal) ring, 430, 1371, 1396
obhque, 430, 1394
Intercuneiform articulation, 304 Interfascial (Tenon's) space, 715 Interfoveolar ligament, 430, 435 Interior of skull, 112
of pelvic, articulations, 235
of posterior talo-calcaneal joint, 301 superior, tibio-fibular joint, 295 membrane of forearm, 263, 264, 1420 muscles of foot, 454, 499
Intertrochanteric crest, 178
Intertubercular (bicipital), groove, 148 Intervaginal space of optic nerve, 1073 Interventricular foramen (foramen of Monro), 847, 874
Ischio-pubicus (Vlacovitoh), 450 Ischio-pubo-femoral musculature, 463 Ischio-rectal fossae, 441, 445, 1384 Ischium, 171
Lieutaud, vesical trigone of, 1252 Ligament (s) (see also "Ligamentum"), 211 alar (occipito-dental or check), 223 of ankle-joint, 298, 1463
of radio-ulnar joints, 261, 264 reflected inguinal (triangular fascia), 430 rhomboid (costo-clavioular), 249 round, of uterus, 1274
of occipital artery, 543
of ophthalmic nerve, recurrent, 935 of posterior ethmoidal artery, 553 of spinal nerve-trunks (recurrent), 970 of vagus, 956
ventricle of, 1222
Morphogenesis, 7 (see also "Development") Morphological axis of scapula, 145 Morphology (see also "Comparative Anatomy")
auricularis anterior (attrahens aurem), 337 posterior (retrahens aurem), 337 superior (attollens aurem), 337 auriculo-frontalis, 337
Naso-lacrimal duct. 111, 1080, 1205, 1349 Naso-palatine nerve (of Cotunnius), 962 Naso-pharyngeal adenoids, 1130, 1354
Occipito-cervioal ligament, 223 Occipito-epistrophic articulation, 223 Occipito-frontal fasciculus, 892 Occipito-frontalis, 336
arteries, lateral, 552
branches of infratrochlear nerve, 937 of maxillary nerve, inferior, 939 of ophthalmic artery, palpebral, 552 of supra-orbital artery, 553
topographic, 1375
variations and comparative, 1197 Pancreatic branches of splenic artery, 595 duct (canal of Wirsung), 1194, 1375 accessory (of Santorini), 1195
of facial nerve, 1345
of median nerve, results of, 1424 of musculo-cutaneous nerve, 1424 of nerves of lower extremity, 1469 of radial (musculo-spiral) nerve, 1424 of ulnar nerve, results of, 1424 Paramedial sulcus, 858
branches of ascending pharyngeal artery, of inferior thyreoid artery, 564 of glosso-pharyngeal nerves, 951 of spheno-palatine (Meckel's) ganglion,
Phreno-colic ligament, 1150, 1174, 1310, 1379 Phrenicohenal (lienorenal) ligament, 1310 Physiology of muscles, 320, 323 Pia mater, 771, 920
sterno-oostal ligament, anterior, 245 Radiation of corpus eollosum, 851 Flechsig's secondary optic, 890 occipito-thalamic (optic), 888
sphajricus (fovea hemisphaerica), 80 Rectal branches of lateral sacral arteries, 608 (hsemorrhoidal) of middle sacral arteries,
Tabatifere anatomique (of Cloquet), 1433 Table showing relations of cervical and thoracic nerves to branches of brachial plex-us, 993
pudic nerve, 1016
of muscles of lower extremity to nerves of lumbar and sacral plexuses, 1016 of muscles of upper extremity to cervical nerves, 993
ligament, urogenital diaphragm, 442, 1384 (lateral) ligaments of liver, 1185 Triangularis (depressor anguli oris), 333
variations and development of, 1249 Ureteral branches of renal arteries, 598 of internal spermatic artery, 601 of ovarian arteries, 602
tibialis anterioris, 483
tendinum musculorum abductoris pollicis longi et extensoris pollicis brevis, 395 extensoris digitorum communis et extensoris indicis, 395
Vastus intermedins (crureus), 468, 470 lateralis (vastus externus), 468, 470 medialis (vastus internus), 468, 470 Vater, ampulla of, 1188
lymphatic nodes of thorax, 724
vessels of abdomen, and pelvis, 733 Visual area of cerebral cortex, 893 Vitreous body or humor of eye, 1052, IO64
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'The tonn "Sftint John Gronp " was first propoHed in 1865 (Observation^ on the Ooolo^y of Houthorn Now limnswiok, Frederioton, N. B., pp. '26-32) by "* <■ i%n. L. W. JJailcy, G. F. Matthew, and C F. Hartt. Snbsequeutly, Mr. J. W. Dawson (Acad. G ol., 'inded., p. 638, 1868) prop< ><">'' asnbstituto the name Acadian for the same fm "nation. Ho nays: " This formation lias as yet boon known an the Saiut John Gr 'p; but I think this nauir ^suitable, both on acconntof the number of places known n-* Mnint John, and on account of the variety of formations occurring near Saint John, in Now Itriinswick, and would therefore propose for the group now under consideration, charactorizod by Paradoxides, Conocephatites, &c., and the oldest known member of tho Pahoo/oic of America, the name Aca<lian Group, by which I hope it will be known to geologists in whatever part of America it may be recognized."
Tlio geographic area bearing tho name of Acadia is defined by Mr. Dawson {ibid., ]i. .'>) as " distingnished from all the neighboring parts of America by the enormons and remarkable development within it of rocks of the Carboniferous and Triassie systems." This certainly renders the name inapplicable as a substitute for a well-defined local name previously given to the formation under consideration.
8aint John, N. U., is quite as well known as Trenton, New York, from which the well-known Tronton limestone is named. We would not give as a reason for changing that name that other towns in the United States bear the name of Trenton.
Mr. Matthew, in speaking of the Saint John formation, says (Trans. Roy. Soc. Canada, vol. i, p. 87, 1882): "From those reports and from the map it will be seen that tho strata of the Saint John Group All a number of narrow, trough-like basins lying between the Bay of Fundy and the central Carboniferous area of New Brunswick. Of these basins, that on which tho city of Saint John is situated is the most important, and it is here, also that the life of tho period can be studied to the best advantage. The Saint John basin lies diagonally across the ridges of Hurouian rock that are found in the eastern part of Saint John County ; and touches the ridge of Laureutian rocks that divides this county from Kings."
I cannot but think that if we pay attention to the law of 'priority, justice to tho original discoverers of this group requires that the name of ^nint John formation Hhoidd be used as expressing tho division of the Lower Cambrian, so well developed at Saint John.
The name Saint John or Acadian cannot well be applied to the Newfoundland or Braiutrec Paradoxides beds. The three localities present local differences and characters which, while permitting their being united under the general term Lower Cambrian, render it necessary to use a local name for the formation in each of the widelyHcparated localities.
thew, obtaiued a large collection of fossils from tbe typical localities at Saint Jobn, Ratcliff's Millstream, and Portland, from wbicb Mr. C. F. Hartt procured tLo collection described by bim in tbe second edition of Dawson's Acadian Geology. Subsequently wben working over tbe material, it was with great difficulty tbat more tban the common species could be identified from tbe descri[)tions, and few figures given in tbe Acadian Geology. Tbe writer at tbat time formed the plan of illustrating the original typical Hartt collection and also the entire fauna, as far as possible. His own collection afterward went to the Museum of Comparative Zoology at Cambridge, Mass., and it was not until tbe latter part of 1883 tbat tbe trustees of Cornell University came in possession of tbe Hartt collection. Through tbe co-operation of Mr. H. S. Williams, paleontologist of the university, the loan of the collection was obtained for tbe purpose of illustrating tbe type specimens and such other material as would add to our knowledge of the faumi. In writing to Mr. L. W. Bailey, of Fredericton, iX. B., and Mr. G. F. Matthew, to secure their cooperation, the writer learned for the first time that Mr. Matthew was engaged on a monograph of tbe fauna of the Saint Jobn formation. The plan of illustrating tbe entire fauna was at once changed so as to include only the H..rtt collection, and Mr. M.atthew was requested to propose specific names for the new species with tbe exception of one form with wbicb tbe writer wished to connect the names of Mr. Hartt and Mr. Matthew, tbe two gentlemen who first gave to the scientific world a definite knowledge of this early Cambrian group. Mr. Matthew kindly accepted this proposal, and the writer proceeded with tbe work, using only the material contained in the Hartt collection.
Mr. Matthew's valuable paper on tbe genus Paradoxides of tbe Saint John Group, has already appeared (Trans. Roy. Soc. Canada, vol. i, 1882), and from it we learn tbat be recognizes three well-defined species and six varieties: Paradoxides lamellatus, Hartt: P. lamellatus, var. ioWca<w«, Matthew ; P. ^ra</tcM,v, Matthew ; P. Uteminictis, 'Matthew, P Eteminicus, vars. siirkoides, breviatus, Quacocnsis, MaHcitns and pontificalis.
In tbe Hartt collection we find as ibe types of P. lamellatus a portion of tbe bead of two specimens. Tbe species appears to be of rare occurrence. Mr. Matthew illustrates but a fragment of the bead of a specimen which he considers as indicating a variety of P. lamellatus.
Two other species occur in the collection tbat were not named by Mr. Hartt. P. Acadicus, Matt., is represented by tbe larger portion of an entire individual, and P. Eteminicus, Matt., by numerous fragments of the bead. Tbe P. Micmac, figured by Mr. Dawson (Acad. Geol. 2d ed., p. 657), is not represented in tbe collection, and Mr. Matthew writes me that the original specimens were destroyed in the great Saint Jobn five of 1877, and that be is unable to identify the species. The figure is a restoration, and no description accompanies it; on this account it ap-
Jobn fauna, as an undefined and undetermined species.
In reviewing the fauna as shown in the Hartt collection, we find the Echinodermata represented by single detached plates of one species, Eocyntites primcevus, Bill. A somewhat similar form occurs in the Menevian group of Wales, under the name of Protooyatites MenerenaiSj Hicks.
Among the Brachiopods, Lingulaf Dawsoni, Matt., Acrothele Matthewi, Hartt, Obolella transversa, Hartt., Obolella, sp., Orthis Billingsi, Hartt, and Orthis, sp. ?, show how rich and varied this class must have been at the time of the deposition of the Saint John formation.
The new type representing the Gasteropoda, Harttia Matthewi, is of special interest owing to its being the oldest representative of the class known on the North American continent, and the section of the family which it approaches most nearly is doubtfully known, if at all, below the Tertiary system. Tiie species Pala;acm€af Acadiea, is as yet doubtfully referred to the gasteropoda.
Of the Pteropoda there are three species, HyoUthes Acadiea, Hartt, H. Danianus, Matt., and H. Micmac, Matt. The former is not unlike H. primordialis, Hall (Sixteenth Ann. Rep. K. Y. State Cab. Nat. Hist., p. 135*), of the Potsdam sandstone of Wisconsin, and the second approaches H. cinetus, Barr. (Syst. Sil. Boh6me, vol. iii, p. 78), of the Cambrian^ of Bohemia.
The class Pcecilopoda, order Trilobita, is the dominant type in the Saint John fauna, as it is in all the known Cambrian faunas, and is represented by Agnostus Acadici's, Hartt ; Microdiacus Dawsoni, Hartt, M. punctatus, Hartt ; Paradoxides lamellatus, Hartt, P. Acadicus, Matt., P. Eteminieus, Matt.; and varieties suricoides, breviatus, MaUeitus, pontijicalia and Quacoensis; Conocoryphe Mattheici, Hartt, C. elegans, Hartt, C. Walcotti, Matt., C. (Salteria) Bailey i, Hartt; Ptyehoparia Robbi, Hartt, P. Ouangondiana, Hartt, and variety Aurora; P. quadrata, Hartt, P. Orestes, Hjirtt, and variety Thersites, and P. tcner, Hartt.
Mr. Hartt, described, in addition to these, Conoeephalitesgeminisjnnostis = Conocoryphe Matthewi; ConocephaHtss formosus — Ptyehoparia Robbi; Conocephalites Aurora = Ptyehoparia Ouangondiana, variety Aurora; Conoeephalifes HaUi = Ptyehoparia Orestes; Conocephalites Thersites = Ptyehoparia Orestes, variety Thersites; Conocephadtesneglectus = Ptyehoparia tener. It is with great reluctance that I reduce the above-named species to varieties and synooyms of other species, and it was not until after many comparisons and a study of all the material in the collection that it was done. Good figures are given of the types of each of Mr. Hartt's species, and the student has before him the original descriptions, so that he can judge for himself and not entirely rely upon the writer to form his opinion of the value of the species.
12 CAMBRIAN FAUNA OP NORTH AMERICA. limuia
In review we And 14 genera, 26 species, and 6 varieties, distril)ute<l as follows : Echinoderniata, 1 genus, 1 species ; Bracliiopoda, 5 genera, 7 species ; Gasteropoda, 1 genus, 1 species ; Pteropoda, 1 genus, 3 species; Trilobita, 6 genera, 14 species, 6 varieties.
That Mr. Matthew's researches will increase this number of species there is little doubt, and it is not inii)robable that some of the species of Mr. Hartt which are plaeed in this paper as synonyms of some others may yet prove to be distinct.
Mr. Matthew states (Trans. Eoy. Soc. Canada, vol. i, p. 89) that among the collections made by the Canadian Geological Survey in New Brunswick, Mr. Billings recognized fragments of the genera Elliptocephalus and Salterella, and the remains of two species of Hyolithes. " Besides these, there are the supposed plant remains, Palaeophycus, Eophyton, etc., of the higher divisions of the Saint John Group."
While studying the species, the question of their correct generic reference came up, and a number of species of three different genera were found to be arranged under the genus Conocephalites, a genus that, with the greatest respect for the opinion of its author and his work, 1 cannot see the way clear to accept. The reasons for this will be found under remarks on the genus Ptychoparia. The new subgenus Salteria may be of doubtful subgeneric value, but with the characters of C. (Salteria) venuloaa, Salter, before us, a subgeneric group, appears to be indicated.
The fauna of the Saint John Group has been most happily compared by authors with that of the Paradoxides fauna of Bohemia, Wales, and Sweden. The resemblance to that of the Menevian of Wales is very striking, and the relationship so close that we are in doubt if there arc not more identical species than Microdiscus punctatua in the two faunas.
Ptychopnria Robbi Plychoparia Emmrichi.
Mr. Matthew calls attention to the close interrelationship of the sp^ cies of the Saint John Paradoxides and to the fact that they belong to SI group characterized by a continuous eye-lobe, a feature developed in Paradoxides rugulosua, Corda (Syst. Sil. Boh6me., vol. i, p. 374), of Bohemia. In the genus Anopoleuus (Quar. Jour. Geol. Soc, vol. xxi, p. 177) the eye-lobes are continuous, but of a different character from the Saint John Paradoxides. Olenellus asaphoides (Amer. Jour. Sci., vol. xiii, p. 205) shows a continuous eye-lobe in some of the younger stages of development, a character not retained in the adult individual.
In comparing the Saint John fauna of Saint John with that of other localities of the Saint John fauna in North America, the first to be noted is that of Manuel's Brock, near Conception Bay, Newfoundland, as described by Mr. J. F. Whiteaves (Amer. Jour. Sci., 3d ser., vol. xvi, p. 224, 1878^.
Mr. Whiteaves identifies of the Saint John fauna : Agnostus AcadicuSf Microdiscus Dawsoni, Mierodiscus jmnct^tUis, Paradoxides, sj). f, C. {Salieria) Baileyi, Ptyehoparia tener, Ptychoparia Orestes f.
On the authority of Mr. Alex. Murray, the shales containing this fauna are considered by Mr. Whiteaves as lower than the strata from which Mr. Billings obtained a strongly-marked Cambrian fauna that he refers to the Menevian Group (Can. Nat., 2d ser., vol. vi, p. 470, 1872).
From this hori;?on Mr. Billings described Obolella f misery Strapafollina remota, Hyolithes excellens, Paradoxides tetiellus, Paradoxides decorns, P. (Anopolemcs) vcnustus, Agraulos affinis, A. socialis, A. strenuus, Ptychoparia (Solenopleura) communis.
Mr. Billings also describes Stenotheca pauper and Scenella reticulata, from Conception Bay, the stratigraphic horizon being a little above the Manuel's Brook shales containing the Saint John fauna. To these we have to add the largo Paradoxides Bennetti, Salter (Quart. Journ. Geol. Soc, vol. XV, p. 552, 1859), and Bathyurtis=Solenopleura gregaria, Billings (Pal. Foss., vol. i, p. 303, 1805), from the Paradoxides slates of Saint Mary's Bay, Newfoundland, which gives a total of fourteen described species from Paradoxides beds above the Saint John fauna.
From the sections given by Mr. Murray (Geol. Surv. Newfoundland, p. 157, 1881), we learn 4hat the shales carrying the Samt John fauna are the lowest fossiliferous strata in Newfoundland, and that the Paradoxides beds above carry a fauna unlike the Saint John fauna. This proves the latter fauna to be the oldest known on the American continent, and when compared to the older Cambrian faunas of Wales, to
the Harlech and Longmynd gronps.
Near Saint John, N. B., there is a commingling of representative species that are distributed in the St. David's section of Wales, from the Harlech to the Upper Menevian, a fact that tells us plainly that we need not look for a close similarity in the succession of individual species in sections of the same relative geologic position when widely separated. The physical conditions of environment and the geographic distribution of species tend to variation in the assemblage of forms at localities but slightly separated, and still more when widely distant from each other.
In the Braintree argillites there are four species, Hyolithea Shaleri, Walcott (this bulletin), Paradoxides Harlani, Green (Amer. Journ. Sci., vol. XXV, p. 336, 1834), Ptychoparia Rogersi, Walcott (this bulletin), and Agraulos quadrangularis, Whitfield (Bull. Amer. Mus. Nat. Hist., vol. 1, p. 147, 1884).
The Paradoxides Harlani is of the type of Paradoxides Bennetti, of Newfoundland, as found above the Saint John fauna, and corresponds to the Bohemian group of the genus typified by P. spinosus, Boeck, and the Menevian P. Hicksii, Salter. Agraulos quadrangularis, Whitfield, is a type present in the Paradoxides horizon in Newfoundland, as A. socialis, A. strenuus, and A. affinis, Billings (Pal. Foss., vol. ii, pt. 1, p. 71), in the Menevian of Wales, as A. longicephalus, Hicks (Quar. Jour. Geol. Soc, vol. xxviii, p. 170), in Bohemia, as A. ceticephaliis, Barrande (Syst. Sil. Bohfime., vol. i, p. 405). Ptychoparia Bogersi is more of the type of Ptychoparia Emmrichi, Barrande, of Bohemia.
have been discovered in North America.
The relations of the Saint John fauna to the remaining portion of the Paradoxides fauna in Newfoundland we havo mentioned, but as yet no section has shown the connection of the Paradoxides fauna with that of the next superior or Georgian fauna. As I am engaged on a review of the latter fauna, the discussion will be omitted here to appear in a paper on that portion of the Cambrian fauna.
ides fauna
The plates are polj'gonal in outline, variable in size and form, elevated at the center, and ornamented by 9, 10, or 11 principal ridges radiating from the center with smaller ridges coming in between the larger ones, usually showing a pentagonal arrangement. The plates vary from 3 to 5 millimeters in diameter. It is quite probable that a new generic form is indicated, but in its relations to other genera nothing can be determined. Protoeystitea Menevenais, Hicks, evidently belongs to a aim I ilar type, if not to the same genus.
Lingnlaf Dawsoni, Matthew, 1884. MSS.
Shell small, broadly subellii>tical, subattenuate towards the beak; margins gradually expanding and curving from the beak to the center, where the shell has its greatest width, and thence narrowing towards the front, which is broadly rounded. General surface depressed convex, becoming more convex towards the beak.
ating lines that are seen only by the aid of a strong magnifying glass.
In form this species approaches i/i/j//M/e//a/(?rr«<jfmca, Salter (See Man, Brit. Foss. Brach., Davidson, vol. iii, p. 336), of the Menevian formation of Wales quite closely, but with only a specimen of the ventral (t) valve to compare with it, it is difficult to satisfactorily determine its specific relations.
on page 644 of the Acadian Geology as a new species of Lingula :
"Lingula, n. sp., Hartt, difl'ers from the above {A. Matthewi) in being almost straight in front, broadly ronnded at the sides, and narrowed towards and p( ' ^d at the umbo. It was also larger, thicker, and more convex."
very thiu ; on each side a segment, such as would be put off by a chord running from the umbo to the extremity of the transverse diameter, is slightly turned up on the margin.
"Inside, a strong mesial ridge, rounded and of moderate width, runs from tbe umbo to a point a little beyond the middle of the shell ; at the umbo this ridge bears a small nailhead-like process or swelling, and there are two minute and extremely short secondary ridges, originating from the head of the primary, and extending obliquely backwards. Inner surface marked with numerous indistinct and irregular concentric striae ; outer surface not visible."
A study of the type specimen of this species, which is a cast of the interior of the dorsal valve, leads to its reference to tlie genus Acrothele, as It presents characters shown in a typical form of Acrothele, A. subaidua, White (Expl. and Surv. West 100th Merid., vol. iv, pt. 1, p. 34), from the Gambrian of Utah. On the list left by Professor Hartt, reference is made to specimen No. 342 as Oholus {Biscina) nitidm, sp. uov. This specimen presents the characters of a ventral valve of Acrothele, and is of the form that the ventral valve of A. Matthewi would probably have, and although not associated with it at Saint John, I have little hesitancy in referring to it as the ventral valve of A. Mattheici. It is illustrated on plate i, fig. 4a.
The above is all the description by the author of the species and no figure is given, but, with the typical material used by him before mc, there is little diflBculty in recognizing the species.
It is closely allied to Obolella sagittalis, Salter, and Mr. Davidson's description of that species (Geol. Mag., vol. v, p. 309, 1868) reads as though it were drawn from the Saint John specimens. Figures are given of the interiors of the two valves.
Obolella? miser, Billings (Pal. Fos. vol. ii, i)t. 1, p. 69, 1874), is a closely allied species from the Saint John formation horizon. No figures accompany the description.
Orthis BilUngsi, Hartt, 1868, Acudiau Geology, Dawson, 2d ed., p. 644, fig. 223.
Description. — "Shell subquadrate to semicircular, broader than long; greatest width at the hinge-line ; moderately convex ; greatest thickness at about the middle ; depressed in fnmt. Hinge-line straight. Dorsal valve semicircular or subquadrate; de]>ressed, with a shallow sinus running from the umbo to the front. Umbo not elevated above the liinge-area, which is very narrow, and marked by fine, parallel longitudinal striie. Hinge-plate bearing two slight incurved internal processes. Ventral valve more arched than the dorsal, with a narrow, flat margin produced in the plane of the valve. Hinge-area triangular, concave, luul marked with tine parallel lines. Umbo elevated above liinge-line about one-fourth of length of shell. Foramen triangular and of moderate size. Surface ornamented by about thirty prominent rounded, radiating plicsB, increasing iu width towards the margin, becoming less elevated and slightly curved toward the ears, crossed by a number of distinctly marked, concentric, squamose lines of growth, and numerous flue concentric stria?. The radiating plica; increase by bifurcation, which takes place at about one-third the distance from the umbo to the margin."
The figure accompanying the above description is that of a rather transverse ventral valve, on which the radiating costse are unusually strong. They also bifurcate in a manner observed in but one other specimen in the collection. At first sight this shell will be separated as a distinct species from the variety, having sharp, somewhat distant ribs radiating from the beak, with finer ribs appearing between them on the cast, but other specimens occur where the two surface chai^ters are shown on the same shell, aud give the im])ressiou that we have a single variable species, the two extremes of which are shown in our figures 1, Id, of plate i. The crowding together of the increased number of ribs on the costate variety gives the bifurcating character to the ribs or costa).
The ventral valve of 0. Billingsi is little elevated, in this respect being unlike other Cambrian species, aud there does not appear to be any nearly-related species of Urthis in strata of Cambrian age. Orthis llwlisi, Salter (see Davidson's Mon. Brit. Foss. Brach., vol. iii, p. 230), is the prevailing form in the Menevian of Wales, and in some of
its phases resembles 0. Billingai. Among the Swedish forms the latter mivy be compared with 0. exporecta, LioDarsson (Bihang till K. Svenska Vet. Akad. Handlingar. Band. 3, N:o. 12, p. 12, 1876).
Plate i, fig. lo.
Associated with the preceding at Saint John, there is a bmall single dorsal (?) valve of a species of Orthis that appears to be distinct from O. BHUngsi. A moderately well-defined median sinus is shown and the surface, as preserved in the cast, was somewhat finely ribbed. Professor Hartt refers to a new species of Orthis as not being sufficiently well rei)re8ented to warrant its description, but gives another specimen, fig. Ic, plate i, as the form. This I consider as a variety of O, Billingni, and the shell under consideration may only have the same position when a larger series comes to be studied.
Ptychoparia.
Description. — A small, oval, patelliforni shell, having a low, broad ridge originating on the posterior (?) side of the interior that supports a subcordate shield-like expansion which extends out over the anterior (?) portion of the interior when we look down into the shell. The broad base of the ridge and the genersil character of the shield-like extension are well shown in the figure on plate i, fig. 3.
The character of the apex s unknown, as the onlj^ representation of the genus and species is in tae form of a cast, showing the interior of the central portion and, around the margins, the cast of the apparently smootii outer surface.
The interior ridge and shield-like expansion is of a peculiar character, and unlike that of any described recent or fossil form known to me. It is so well marked that there is little hesitancy in proposing a new genus for its reception. The genus may be included in the Oalyptraiidie nearest the genus Crepidula, if we compare the shield-like expansion with the shelf or shelly partition of Crepidula. However close or distant its relations to the latter, it certainly appears to be the representative of the Calyptrieida; type in the Cambrian, and adds another form, showing the ditterentiation of the invertebrate fauna in the oldest fauna yet known on the American continent.
certainty clearly shown.
There is no reference or record number attached to the specimen, and nothing is said of it in Mr. Hartt/s notes as published by Mr. Dawson. A scratched outline around the specimen shows that it had been noticed, but whether by one of the collectors of the specimens or by Mr. Hartt is unknown.
Formation and locality. — Cambrian. Saint John formation. The character of the slate and the embedded fossils is similar to that of the material from liatclitf 's Millstream, and it was associated in the collection with specimens from that locality.
Description. — " Shell elliptical in outline; sides more or less straight. Conical, but very depressed. Apex apparently central. Surface marked with a number of deep, concentric, irregular, sharp furrows, not always continuous, and often breaking up into smaller grooves, and all these seem at times to be impressed with lighter lines running nearly parallel with them. Of the large furrows from nine to ten can nsnally be counted. The whole surface of the shell is marked with a great number of delicate raised lines radiating from the summit to the circumference, and just visible to the naked eye."
An examination of several specimens of this species, including the tyi)C8, leads me to. think with Mr. E. P. Whitfield (Bull. Amer. Mus. Nat. Hist., vol. i, p. 141, 1884), that it is not a true Discina, but probably a univalve shell, allied to Palajacmea or Stenotheca. The material in the collection is very poor and fragmentary ; so much so that the generic reference is to be considered as merely provisional.
Theca Acadica, Ilartt. Label on Hpocimon.
Forui an elongate triangular i)yranii(l, tapering gradually and unifornaly to an acute extremity. Transverse section subtriaugular, about twice as wide as high ; the lateral angles acute from comi)re8sicn in tbe specimens in tbe collection. Ventral face slightly arched; anterior margin extending forward in a semicircular subspatulate extension. Dorsal surface rather strongly convex. Aperture unknown, but undoubtedly oblique, judging from the character of the extension of the ventral side.
Operculum unknown.
Surface of shell miirked by concentric lines of growth, parallel to the margin of tbe aperture, and exceedingly tine longitudinal strisB visible only by tbe aid of a strong magnifier.
In general form this species approaches very closely to Hyolithes AmericanuK, Billings (Can. Nat. n. ser., vol. vi, p. 215, 1872), but tqually so to the Devonian If. aelia. Hall (Pal. N. Y., vol. v, pt. 2, p. 107,) exce])t in the more rounded dorsal side.
Owing to the imperfect condition of preservation of the species illustrated from the Menevian group of Wales, it is difficult to ibake comparisons with them. Professor Ilartt's specific name is retained, as the probabilities are that the form is different from the American Potsdam and Georgian species, although allied to H. primordialis, Hall (Sixteenth Ann. Kep. State Cab. Nat. Hist., p. 135,* 1863), and also the Menevian forms of the genus in Wales.
Hyolithes Danianus, MatthewH, ld84, MSS.
Form that of an extremely elongate rounded subtriaugular pyramid that, in some examples, curves a little to one side as it becomes gradually attenuate towards the apex. Transverse section semielliptical ; moderately convex on the ventral side and still more so on the dorsal. Ventral face flattened and almost concave along the center, rounding up on each side to the somewhat rounder lateral angles. Dorsal face not very strongly convex transversely. Form of aperture unknown.
Associated operculum broad oval, or subcircular in general form. The side corresponding to the ventral side of the shell curves regularly, but is not as convex as the opposite side. The umbo is* situated
FAUNA OF THE SAINT JOHN FORMATION.
about four-fifths the diHtauce from tho dorHul niargiu, and extendH laterally as a low, rounded rid^e towards the rounded angles formed by the union of the ventral and dorsal sides of the operculum ; just in front of these ridges a slight depression exists, also a depressed area back of the umbo, or towards the dorsal margin ; the inner side shows a Hharp ridge corresponding to the umbonal ridges on the outside, and also a sharp, short, elevated ridge between the ventral margin and the ]»osition of the umbo on the outer surface. The general bo«ly of the sliell of the o])erculum appears to have becMi (piite thin.
Surface of the shell marked by transverse, concentric undulations of growth that arch slightly forward on the ventral side. Outer surface of the oi)erculum marked by fine concentric strise and very tine, somewiiat obscure, radiating stria; ; inner surface with fine, slightly irregular, radiating lines or stria;.
There is considerable range of variation in the form of the shells of this species. In some the flattening of the ventral side is lost, and only a convex surface is shown, and the dorsal surface has a narrow longitudinal lino on each side of the center. The curvature of the shell also varies considerably. A number of specimens of the operculum are associated with the shells, but none were observed attached before the mouth of the shell.
One unusually curved shell having a nearly round section, was labeled Orthoceras 1 n. sp., by Professor Ilartt, as trac(;s of what appear to be septa are shown. The distances between the septalike partitions are unequal, and in other specimens this is seen to be owing to tlie filling of cracks across the tnbe.
j nyoUthea Micmac, Matthew, 1884, MSS.
Form that of an extremely elongate, ronnded, subtriangular pyramid I tliat becomes gradually attenuate towards the apex. The true transverse section is not preserved, owing to the crushing down of the shell, I and appears to have been semielliptical or rounded subtriangular.
In form this species is not unlike Hyolithes Danianus, but the smooth |outer surface and striated inner surface distinguishes it from that and ilso any other described species known to me.
T)iii)enHinnR : Length of Ht)ociiii»ii 20""", width at tti»orturp 4'°">. Formation and locality.— CaiuhriAii. Saint John formation, aiiBooiated with Microdiscus punotatus at Uatcliff's MillHtreani, N. B.
Description. — "Head minute, transversely-elliptical, or snbcircular ; breadth and length about equal, convex but very depressed, outlines in front and on the sides sliglitly straightened. A narrow, flattened, and but very slightly elevated border goes round the front and lateral margins. This is separated from rest of shield by a narrow, shallow, flat space, or groove, which, on going posteriorly along the lateral margins, loses gradually in width toward the posterior angles of shield, which are rounded. Glabella a little less than two-thirds the length of | shield, long elliptical, depressed convex, but more elevated than other parts of the shield, about twice as long as broad, bounded anteriorly and laterally by a sharp, rather deep groove concentnc to the outer one above described. A well-marked transverse furrow, arching backwards, separates the anterior third of the glabella as a subcircular lobe. Posterior part of glabella rounded, but impressed on each side by a little lobe situated in the angle between the cheek-lobe and the glabella. These little lobes are about one-quarter the size of the anterior glabellar I lobe. Cheeks of the same width throughout, and uniting in front of j the glabella, being bounded by the two concentric grooves above mentioned. Posteriorly they are rounded ; in width they are rather greater I than the glabella. They are convex, more elevated along their inner margin, but sloping outward roundly and evenly. Glabella with its [ lobes project considerably beyond posterior margin. Surface smooth. Pygidium of this species (?) of abdut the same outline as cephalic shield. The posterior and lateral margins have a slight, raised border, separated from lateral lobes by a shallow but well-marked groove running par allel to the margin. This groove widens at the point where it bends to I go forward along the sides in such a way as to encroach on and thin out | the marginal fold, and, just before reaching the anterior margin, it narrows Itself from the inner side so as to cause the lateral lobes to widen somewhat anteriorly. These are narrow, flattened, about half as wide as the middle lobe, narrowing to a point just behind the middle lobe, where they do not unite. The medial lobe is about five-sixths of leugtL of pygidium, shield-shaped, flattened, convex, more elevated than the lateral lobe. Its anterior border is slightly concave in the middle. | The lateral angles are rounded, and the lobe is contracted a little an-
t4>iiorIy. It is bouuded by two deep and well-uiarked fiirrowR, which join one another in the middle of the nnirginalfnrrow, forniinf; a pointed arch. Medial lobe projecting further forwards than the lateral ones. A little spine is situated on its mesial line about one-fourth its length fioni front. Surface smooth."
Alter a careful study of all the specimens in the collection, fifteen in luiinbi'r, I am unable to make out sufficient difl'cronces between the form *lt>N<;ribud as A. AcadicuH and that given as A.nimilui, to ('tstablish two Hpocics. There is a certain range of variation in the specimens as {tointod out by Mr. Hartt, but that is so variable and owes its origin so largely to the condition of preservation of the various specimens that it is not evident that two species are typified.
Agno8tun Acadicvs is a type of the genus that occurs in the Menevian of Wales, as A. Cambrensis, Hicks (Quart. Jour. Geol. Hoc, vol. xxvii, J). 4(M), 1871) ; in Norway, as A. brevifrons, Angelin (Pal. Scan., p. 0, lSo'2) ; in Bohemia as A. integer, Beyr. (Sil. Syst. BohCmie., vol. i, p. 900, 185;^) ; and in the American Potsdam horizon as^. JV>o», Hall & WhitttoUl (Geol. Expl. 40th Par., vol. iv, p. 229, 1877). Agnvatus interatriv<««,. White (Expl. and Surv., West 100th Merid., vol. iv, p. 38), from the Cambrian of Utah, is an almost identical species, diit'ering princi-
Description. — " Cephalic shield semi-lunar, with thickened border crossed by numerous grooves running perpendicularly to the circumference. Glabella convex, narrow, rounded in front, conical and pointed behind, projecting beyond posterior border, without furrows or occipital groove. Cheeks convex, no eyes, and no traces of sutures. Posterior angles of shield with backward projecting opines. Pygidium subtriangular, with curved outlines, rounded in front and behind ; middle lobe distinctly marked, and divided into six segments ; lateral lobe also divided, furnished with a narrow border."
J. W. Dawson. .
Head semi-elliptical in outline, rather strongly convex, and bordered on the front and sides by a depressed furrow and raised rim, the furrow containing numerous short furrows perpendicular to the margin, as ir. M. Dawsoni, but not as strongly marked. The posterior border is strong back of the cheeks, and has the furrow continuing from the sides ; a very narrow rim extends back of the glabella ; eyes and facial suture entirely absent.
Glabella elongate conical, extending ba( kward in a strong spine as long as the glabella in medium-sized specimens and nearly as broad at the base. In some examples the spine is shorter and smaller. The glabella rises above the level of the cheeks and is about three-fifths the length of the head, bordered by strong dorsal furrows that are connected in front by a straight furrow with the depressed groove within the anterior marginal border, perceptibly marked by two pairs of oblique glabellar furrows in some examples. Cheeks convex, prominent, strongly defined by the dorsal and marginal furrows.
Thorax unknown.
The pygidium, associated with the head of this species in great numbers, has the same general outline as the head. The narrow marginal rim is well defined all around, w idest at the sides ; anterior marginal furrow very distinct; median lobe elongate-conical, extending back uearly to the marginal groove ; nine anchylosed segments are indicated by eight rather strong transverse furrows ; lateral lobes strongly convex, no furrow appearing back of the anterior marginal groove.
This is an abundant and well-marked species. Mr. Hartt evidently intended to describe it, as the name is given in his list, and selected specimens were mounted on blocks, one of which bears the name Eodisous pulchellus, Hartt, n. g., n. sp. There is considerable variation ii; tho relative proportion of the length and breadth of the head, also of the pygidium in difl^e^ent specimens, owing to an original variation, and also distortion from compression in the shales.
Primordial slates of Saint Jo!it),*N. B., by the late Mr. E. Billings. It has since b^en observed in rocks of the same age on the Kenuebecasis Kiver, N. B., where it was collected by Mr. G. F. Matthew.
In comparing with the flgnres of M. pnnctatus given by Mr. Salter, it, is observed that the nuchal spine of M. punctatus is longer and more slender, and the su^iace of the cephalic shield and pygidium are pi ictate, whereas, in the Saint John's specimens, the surface is smooth, in event of the two forms proving distinct on a comparison of specime^is, 1 i)ropose that Mr. Hartt's name, M. pxiMiellus, be given to the American species.
Description. — "This is a small species distinguished from several others found with it by the presence of a number of sharp perpendicular laminae on the anterior lobe of the glabella."
The types of this species consist of the casts of portions of two heads, both of which are illustrated on plate iii. It is, as stated by Mr. Hartt, distinguished from the associated species by the sharp perpendicular liimin?e or ridges in front of the glabella.
Mr. Matthew has indicated a variety as i*. lamelatvs, var. loricatus. Tlie elevated ridges on the front of glabell:' are variable in the two type siwcimens, and I should not consider the v riation cited by Mr. Matthew as of sutiicient importance to establish a varietal name, especially as he suggests the idea that the transverse ridges or interrui>ted elevated lines owe their origin to the condensaticn of the front id area by transfer to the glabella ; this would necessarily induce a great variation in the form and arrangement of the elevated lines in relation to eacli other, although they might retain their general relation to the frontal margin.
liis uot having time to work out the details (Acadian Geol., 2d ed., p. 057, 1868). One of these Mr. Matthew, in his valuable paper on the Puradoxides, has named P. Aeadicus, describing it as follows :
"The anterior margin is regularly rounded and strongly arched backward. The marginal fold is moderately convex and about twice as wide at the extremity as in front of the glabella. The flat area is very small, and at the suture about as wide as the marginal fold.
"The glabella is about an eighth longer than wide. It expands regularly from the base to a point somewhat in advance of the fourth furrow, whence it is regularly rounded to the front.
" The glabellar furrows are all heavily cut. The first two cross the axis of the glabella; of these the first is arched decidedly backward, and is somewhat more heavil^"^ impressed in the outer than in the middle third. The second furrow strongly indents the glabella parallel to the transverse axis ; it is more lightly impressed in the middle quarter than elsewhere. The two anterior furrows are in pairs. The third fails to cross the glabella by less than a third of the glabella's width ; it begins within the margin of the glabella and is directed forward at an angle of about fifteen degrees. The fourth furrow begins on the edge of the glabella, and scarcely extends one-quarter of the way across it.
" The occipital ring is more than twice as long as wide ; it m regularly convex and moderately arched vertically ; a little behind the middle of the ring is a short tuberculous spine. In some of the largest heads the middle half of the ring is raised into a broad, rather flat, lobe which bears the spine. The occipital furrow is more strongly impressed in the outer quarter than in the middle.
" The posterior margin is moderately arched backward ; the fold is regularly convex and moderately arched vertically. The furrow is scarcely as wide as the fold, and is rounded in the botto.Q.
" The fixed cheek is subtrapezoidal in form, iscojivex, and has an elevation at the posterior inner angle ; it is strongly depressed in front, and the bounding furrows are distinct. The ocular lobe makes an open parabolic curve, and is prominently raised all round, but especially at the extremities. The curve of the posterior third of the ocular lobe in this species is more open than in that of the preceding species or its varieties.
" Scvlpture.—PoiraUe] raised lines appear only on the fronthalf of the marginal fold, where there are about five. Elsewhere the surface of the test is covered with closely-set granulations visible to the naked eye.
In the Hartt collection there is a specimen that adds materially to our knowledge of the species and the group of species to which it belongs, as fourteen segments of the thorax, the pygidium, and a portion
of the head ar« preserved. The head parts appear to be identical with the typical form described by Mr. Matthew, and are ornamented by the {,'ranulated surface, characteristic of the species. The thorax is very broad in proportion to its length, even though the fourteen segments preserved are not considered as entirely forming it. The allied Bohemian type, Paradoxides rvgulosus, Corda (Syst. Silur. de Boh6me., p. ;U7, i)hite8 ix and xiii), has but sixteen segments and the specimen under consideration shows no traces of more than fourteen ; the anterior segments, however, are crowded down somewhat, and the head pushed to one side, which leaves the question of the actual number of segments unsettled. The median lobe is crushed together, but still shows that it had a width of 7'""" or 8""" at the twelfth segment, the ])leural lobe on each side of the same* segment extending out 12°"" from the median lobe and terminating in slightly curved mucronate points of the same length on all the segments ; posterior)/ the median and lateral lobes contract, the pleural portion of the last four segments exl)auding and bending back so as to close down to the side of the l),v<;idium ; the pleural grooves are well marked and extend out about half way on the pleural lobe. The pygidium is the type of that of r. rngulosus, {loc. cit), and corresponds to figure 19 of plate x of Mr. Matthew's paper more closely than any other.
Formation and locality. — The locality is not given with the specimen, but Mr. Matthew cites the species from Portland, N. B., and the lithologic characters of the shale correspond to specimens from that locality.
Mr. Matthew gives a very elaborate description of this fine species and divides it into P. Eteminicus and four varieties, viz: Suricoides, breviatns, Quacoensis, Malicittis, ami pontijicalis, tlie diflPerences separating each api>eariiig in the glabella, fixed cheeks, and the anterior lateral limbs. From our experience with the varying forms of Olenellus from Nevada, we should .scarcely consider these, on the evidence given, as more than varieties of one species, as Mr. Matthew has done. A number of specimens of this species occur in the collection.
Description. — " Head semicircular to seini-elliptical, more than twice as wide as long; front and lateral margins forming a regular curve; posterior margin nearly straight; posterior angles of shield flattened and rounded without spines; margin with a strong, round, rather narrow fold, which becomes narrower and lower towards the posterior angle of shield, where it disappears. This is separated from the cheek-lobes by a very deep, moderately-broad groove. This groove is arched forward in front by a large, semi-globose swelling, situated just in advance of the glabella, encroaching upon the marginal fold, causing it to be the thickest on each side of this prominence.
"The posterior margin is also folded, but the plait io more or less inclined backwards. The fold is narrow near the occipital ring, but grows more prominent and gains in width towards the posterior angle, but, like the anterior fold, it disappears at that point. Its course is not straight; at about half ihe distance of the outer angle it bends slightly backwards and downwards and then forwards slightly to disappear on the flattened or rounded angle of the shield. This fold is separated from the cheek-lobes by a groove shallower and broader than the marginal one, which it resembles, by expanding gradually into the flattened space of the outer angle. This groove follows a course parallel to the fold which it accomiianies. Length from occipital furrow, about half that of head.
" Glabella subconical, longer than wide, strongly rounded in front, and about half as wide anteriorly as posteriorly ; length about that of whole shield, strongly convex, but less elevated than the check lobes, bounded laterally and anteriorly by deep grooves, the anterior being not so deep as the posterior. Tbe sides of the glabella are impressed and divided into lobes by three pairs of deep lateral glabellar furrows. Those of the posterior pair are the longer and more deeply impressed. These furrows begin abruptly at a point somewhat in advance of the middle of the longer diameter of the glabella, and directed backwards at an angle of about 45° to the anteroposterior diameter of the shield, disappear abruptly without gaining the medial line, usually extending a little more than the third of the distance across the glabella. Those of the median pair begin also on the bounding groove very abruptly, only a little in advance of the posterior pair, but they are usually not so oblique, and extend on each side not more than a quarter of the distance across the glabella. The distance between the outer extremity of
the median and anterior furrows is somewhat less than between those of the median and posterior, and these buii slightly impress the sides of the glabella, and occasionally are scarcely visible. The anterior lobe is about as widt as the one which follows it.
"The occipital furrow is deeply cut in the outer third of its length and strongly directed forwards ; in the middle third it is not so deep and is quite strongly arched forwards. The occipital ring is narrow, strongly convex, and vertically arched, the sides being more or less narrowed, turned downwards and forwards, being projected obliquely more or less across the posterior marginal cheeii-groove towards the inner posterior angle of cheek-lobe. The ring projects backwards beyond the margin, but not beyond the posterior lateral angle of shield. The middle part is produced into a very short conical tubercle-like spine, directed slightly backwards. The cheek-lobes are strongly gibbous, and very regularly arched, the convexity being stronger anteriorly. A narrow, distinct, wavy ocular ridge begins on the cheek-lobe, just opposite the anterior part of glabella, and, thinning gradually out and arching, at first slightly forwards, curves round and is directed towards the outer angle of cheeklobe, but it usually vanishes before reaching that point. From its anterior outer side it throws ott" a very numerous set of fine, bifurcating, raised lines of ridges. These linesare directed outward from the primary line at a rather acute angle, and appear to bifurcate several times. This ocular ridge is thickened at its commencement, but is not so strongly marked at that point as in C. Baileyi. It is also more arched forward than in the latter species. The whole outer surface of the shield is covered by innumerable, close-set, raised points or granulations, just visible to the naked eye, but very distinct under the lens, appearing in the impression of the shield as minute punctures. These appear to be more distinct on the convex portions of the shield. The raised margins, cheek-lobes, glabella, occipital ring, as well as the lobe just in advance of the glabella, bear sparsely-sown, minute, short spines, which give to the surface a distinct granular appearance. These are always wanting iu the furrows and on the cheek-lobes, are more crowded on the outer halves of the cheek-lobes. They are true spines, but usually appear as granulations on the casts.
" In very young specimens, a line in diameter, the shield is semicircuhir, the cheek-lobes are extremely gibbous, and very much more convex than the glabella, and the preglabellar lobe is vei'y conspicuous."
The above description gives all the characters of the adult head of this species as shown in the specimens contained in the Uarct collection. A number of small heads show embryonic features, but as Mr. Hartt did not describe these and Mr. Matthew is at work on the species and its stages of development, we will await the appearance of his paper.
Mr. Linnarsson unites Conocoryphe coronatux, Barr. (Syst. Sil. de Boheme., vol. i, p. 424, plate xiii, tigs. 20-20), C. exxidanit^ Linnarsson (Sv. Geol. Unders. Afh., Ser. C, N:o. 35, p. 17, 1879), C. solvcnsis,
Hicks (Qnar. Jour. Geol. Soc, vol. xxvii, p. 400, plate xvi, flg. 8, 1871) and 0. Matthewi, Hartt, as a natural group chiefly characterized by the boss or elevation in front of the glabella. He speaks of C. (Elyx) laticeps, Attg. (Pal. Scan., t. 5, figs. 2-3, 1854), as the nearest allied from among Swedish species, and there appears tc be good reason for placing it very close to, if not in the G. coronatus group.
Mr. Corda proposed the generic name Ctenocephalus (Prodrom. Mon. bohm. Trilobiten,p. 142) for this type of theOonocephalidae, and in many respects it is a convenient subgeneric terra.
I know of no American species from the Potsdam or Georgian horizons that will fall within the group, although a species from the Georgian horizon, in Central Nevada, Ptychoparia Linnarsaoni, Walcott (Pal. Eureka Uist., in press), has a boss in front of the glabella much the same as that in C coronatus. The presence of large, free cheeks, well marked eyes, and facial sutures, places the species in the second division of the Conocephalidae under the genus Ptychoporia, or a subgenus of the latter.
Mr. Hartt describes a second species of this group under the name Conocephalites gemminispinosus, as follows : " Resembles C. Matthewi, but with wider and less elevated marginal folds ; clieek-lobes much more gibbous and semi-ovoid, &c., sparsely sown with minute spines, grouped two and two. Rare, at Saint John." This species does not appear on the list of numbered specimens, and I fail to find any specimens that differ from the typical forms of C. Matthewi sufl3ciently to warrant a separate specific name. Under the circumstances it appears best to place the name as a synonym of C. Matthewi, on the grounds of imperfect description, no illustration, no labeled type specimen, or a form iu the collection that can be recognized as the one referred to oy the author. Specimen No. 91 is referred to as G. Matthewi var. ?. This is a well-marked variety in its surface characters, as the scattered tubercles of C. Mattheici are crowded together and give the glabella, cheeks, frontal lobe, and margins a granulated appearance quite unlike C. Matthewi. The ocular-like ridges are also lost iu the crowding together of the tubercles; flg. 1 b., pi. iv.
Formation and localities. — Cambrian. Saint John formation, Ratclift''8 Millstream, Saint John and Portland, N. B. The variety (= granulata) is labeled Cold Brook (= Portland, on authority of Mr. Matthew).
CONOCORYPHE Walcotti, Matthew.
"n a letter received from Mr. G. F. Matthew May 22, 1884, written „]nce the preparjition of this paper, he states that he has found a spi ies of Conocoryphe in the Saint John formation, characterized by trausverse bars on the glabella, a granulated but not tuberculated surface, and other features separating it from the other species of tho genus. For this species he proposed the name Gonocoryphe Walcotti m
Subgenus SALTERIA, n. subgen.
Dr, Henry Hicks, in his description of Erinnys venulosn, refers the species to Salter (Brit. Assoc. Rep., 1865), where we find the name used and the relations of the genus to Harpides pointed out, and the fact stated that it has a great number of free segments and no facial sutures and probably no eyes. The description of Erinnys venulosa (Quart. Jour. Geol. Soc, vol. xxviii, p. 177), is of the type specfes, and gives that of the genus as far as known.
<' Head semicircular, margined all round, but with no posterior spines wider than the body. Glabella small, occupying only about two-thirds of the length and about one-fifth of the width of the head ; pyramidal iu shape, slightly raised, and indented by three pairs of furrows, the hinder ones i eaching backwards nearly to the neck-lobe, and marking ofl" triangular lobes on each side.
'' There are no distinctly-marked eyes or facial sutures, but a tolerably strongly -raised ridge strikes off on each side from opposite the upper ghibellar lobes towards the posterior angles, reaching nearly two-thirds of the distance across. From these ridges lines strike off in each direction, especially forwards, dividing and subdividing in their course and giving a veined character to the whole surface.
" Thorax composed of 24 rings ; axis narrow, convex, and tapering towards the tail ; plearfe compressed, grooved, and, including the spines, more than twice as long as the rings of the axis ; spines bent backwards from the fulcrum, at which part the surface becomes suddenly raised into a sharp, transverse ridge.
with it.
The first generic use of the name Erinnys of which we have record, was by Mr. Schrank (Faun. Boica, vol. ii. p^. 1, p. 152, 1801), for a genus of Lepidoptera. Mr. Schrank spelled the name " Erynnis." Mr. Agassiz suggested in his Nomenclator Zoiilogicus, 1846, that it be changed to Erinnys. The name was again used by Mr. J. Thompson (Arch. Ent., vol. i, 1857) for a genus of Coleoptera. In 1865 Mr. Salter proiiosed it for the genus under consideration, and in 1867 it was again proposed for a genus of Coleoptera by Mr. Oustalet (Scudder Index Univer., p. 115). As Mr. Salter's name was anticipated, it becomes
necessary to replace it, and the name Salteria is proposed in honor of the distinguished paleontologist. The generic description, as far as known, is essentially that of Salteria venulom. With it we may place 8. Baileyi, as it is an almost identical species, as far as can be determined from the head and pygidium.
Description. — "Head transversely semi-elliptical, half as long as wide; anterior margin in front more or less straight ; posterior margin quite straight ; posterior angles of cheeks slightly rounded and unfurnished with spines; facial suture never visible ; anterior margin of shield with a narrow, very elevated border, which is widest and most elevated iu front, and grows narrower and lower posteriorly, becoming obsolete, or nearly so, at the posterior angle of the shield. This border is separated from the other part of the shield by a deep, rather wide furrow, whicli is deepest in front, but grows shallower as the anterior border loses in height going posteriorly. General form of shield convex, but much depressed ; glabella more depressed than the cheek, subtriangular, depressed convex, broadly rounded in front, and separated from the cheeks and front by a deep, well-marked furrow ; width at base equal to length, which last is about seven-tenths that of shield ; very much narrowed in front. Lateral bounding furrows inclined to one another at such an angle as would cause them to meet if produced to the middle of the front margin of head. Occipital furrow deep and well marked, slightly arched forward in middle, and curving downward and forward, growing narrower at the extremities, and less deeply cut than the bounding furrow of the glabella. No lateral glabellar furrows, or very slightly marked, ever seen on casts. Occipital ring more elevated and rather wider in the center; bent forward at the sides; narrow, with a very low, spine-like tubercle in the center. Posterior furrow moderately deep and wide. Sides of shield bent slightly downward. Posterior angles flattened. Cheeks subtriangular, bounded by the straight dorsal furrow, the straight groo^'^e which separates them from the glabella and the curved marginal furrow. They are more convex or gibbous than the glabella, sloping gently toward the marginal furrow, but steeply to the other bounding grooves. In the cast they are marked on the edge of the bounding groove of the glabella .at the i)oints where the straight sides of the latter begin to curve around the front by two small, low, but well-marked ocular prominences, from each of which extends a slight ocular ridge, with a more or less outward curve toward the | posterior angle of the shield, but usually loosing itself at about half the distance in a system of delicate ramifications, which may often be traced to the posterior angles of the cheek lobes. Like ramifications are thrown
off for the whole leugth of the ridge from its auterior side, .lud these occupy the surface of the cheek lobes in fronf of the line. The surface of tiie cast sometimes appears granular, but the mould is always smooth, luid the outer surface of the shield was unfurnished with tubercular or jjraiuilar ornamentation. The posterior border on each side of glabella is very elevated in the middle, and loses height thence each way. Cei)halic shield sometimes an inch and a half in width."
On one specimen referred to this species the left posterolateral angle of tlie head shows a short, slender, rounded spine, a feature not mentioned in the original description, and a short facial suture cuts ott' a slender strip of the postero-lateral side of the cheek, carrying the spine witL it.
Tlie resemblance between the head of this species and that of G. (^(, ria) venulosa is very striking, the greatest difference appearing in the presence of a suf^ure line and postero-lateral si)ine. I suspect, however, that, as in the case with C. {S.) Baileyi, the free cheek and spine arc broken away in C. {S.) venulosa, and have not been observed, owing to that. One specimen of C. [S.) Baileyi preserves twelve segments of the thoi-ax and the pygidium. The latter is of the type of that of C. {S.) venulosa, but the thoracic segments vary considerably at the genal angle of the pleural lobes and in the rounded instead of falcate terminations of the pleurae. The true number of segments in the thorax is unknown.
Description. — "Head or cephalic shield semi-circular or semi-elliptical, more than twice as broad as long, nearly straight behind; auterior border with a very strong fold, separated from the rest of the head by a deep groove. At this point the groove bends abruptly and angularly, and arches forward on each side so as to encroach on the marginal fold and cause it to disappear at about half the distance between the middle point in front and the posterior angles of shield. The posterior marginal folds are very thin, most elevated in the middle, and sloping each way towards the occipital ring and posterior angles of shield. The axis of the outward half is more and more inclined backward from the perpendicular towards the posterior angles, which are rounded, more or less flattened, and with out backward projecting spines. The grooves separating the posterior fold from the cheeks are very deep, and are slightly directed forward. Length of glabella about sixth-tenths of anteroposterior diameter of
shield, a little wider at base thau long, and less than half as wide anteriorly; triangular, with anterior part rather broadly rounded, highly inflated, and bounded by deep grooves, which in front join in with the anterior marginal groove. There are three pairs of glabellar furrows. Those of the posterior pair impress deeply the sides of the glabella, are strongly curved backwards, aad scarcely reach a third of the distance across each side. The second and third pairs only just impress in like manner the sides of the glabella. Those of the second pair are curved backward, and extend about a quarter of the distance across the glabella. Those of the third pair are very short, and appear to be parallel with the transverse diameter, but they are not always distinct.
Occipital furrow <leep, slightly arched forward in the middle, and with the ends turned in the same direction ; occipital ring of moderate width ; the middle is produced into a spine often mure than a quarter of .an inch in length. This spine is more or less strongly directed backwards. The cheek-lobes are very gibbous, more so than the glabella. Their posterior bordci- is so strongly impressed by the posterior furrow that it arches slightly over it. The surface of the convex i>art of the shield is ornamented by very line, close-set granulations, distinctly visible to the naked eye, and by a set of delicate little tubercles more sparsely sown.!'
This distinct and finely ornamented species may be compared with Conocoryphe bufo, Hicks (Quart. Journ. Geol. Soc, vol. xxv, p. 52, 1869). In the form of the head, frontal margin, and glabella, the character of the granulose surface and absence of facial sutures and eyes, as far as known, they are very much alike. We know of the presence of the postero-lateral spines of the head in C. elegans, but not the occipital spine in C. bufo which is present in C, elegans. Conocoryphe Dalmani, Angelin (Pal. Scan., p. 63, pi. xxxiii, fig. 16, 1854), belongs to the same group of species and is very closely related to them. Liunarsson speaks of C tenuicincta, Linn., C. emarginata., Linn., C Dalmani^ and C. hufo as forming a natural group (Sv. Geol. Unders. Afh., 8e. C. N:o. 35, p. 20, 1879), and with these we add C. elegans^ as it is a similar type .and nearly identical with C. hufo and C. Dalmani. ,
In looking up the history of the generic names Conocephalus, Conocoryphe, Ptychoparia, and Conocephalites, we find that Conocephalus was first proposed by Mr. Zenker in 1833, with C. Sulzeri as the type, a trilobite without eyes and having a peculiar direction to the facial
In 1839 Mr. Eiimirich doacribed, an a diHtiiict species from C. SuJzeri, ConoccphulvH striatun, rel'erriiiff it (o the same genus, although it bns \vell-(U'Veh)j)ed eyes ami a direction of the lucial sutures ludike that of C. Siihcri.
Mr. Corda, in 1H47, observed that C. Suheri and C./<frm^«» represented two generic groups, and as the name Conocei>hiilus had been preoccwl)ie(l tor a genus- of insects in 1812, lio i)roposed two generic names for the two types, Conocoryphe being given to G. Sulzeri and Ptychoparia to C. Htrialus. This division appears to me to be one dem.auded by the cliaracters of the two types, and I fully indorse the opinion of the late Mr. ¥. li. Meek (Sixth Ann. Kep. U. S. Geol. Surv. Terr. 1872, p. 487), tiiat Mr. Corda's names should be adopted and the subsequent name, Couocephalites, proposed by Mr. Barrande in 1852, treated as a synonym. Mr. Corda used the same type species in proposing the genus Conocoryphe, and there does not appear to be sufficient reason for refusing to adopt the name. Of the value of the genus Ptychoparia paleontologists may differ, but if we unite before our minds the characters of Ptychoparia striata and P. Emmrichi, the tyi)es referred to by Mr. Corda, and then bring together the group represented by Conocoryphe Suteri, G. coronatua, C. exsuJans, Linnnrsson, G. solvensia, Hicks, and C. Matthetci, Hartt, in the same manner, we will observe differences that, to me, appear to be of undoubted generic value. This division may be carried still further if we adopt Mr. Corda's third division of Conocephalus, Ctenocephalus, as a subgenus of Conocoryphe, and place C. coronatus, G. Matthewi, C. exsulamt, and allied species under it. From Mr. G. F. Matthew's study of G. Matthewi I am very much inclined to adopt Ctenocephalus in that manner.
Mr. Meek (loc. cit.) thinks that in adopting this view the generic name Ptychoparia will necessarily be applied to nearly all the species of the Conocephalidsf described from American rocks. With some considerable exception this is true, and especially so of the group placed under the generic name of Crepice})hahis, by Messrs. Hall and Whitfield (Geol. Expl. Fortieth Par., vol. iv, p. 209, 1877). They revived the genus w hich was proposed by Mr. Owen (Geol. Surv. Iowa, Wis., and Minn., p. 576), making C. Haguei the first species.
For the purpose of i)lacing before all the means of comparing the types of the two genera, they are figured side bj' side on plate v. Ptychoparia striatus, the type of the genus, has two more segments in the thorax than P. Haguei, but that is not a character of generic value of itself. Of Mr. Owen's type of the genus Crepicephalus, G. loicensis, only the head is known, although the pygidium usually associated with the head is peculiar and might give rise to a subgeneric group, but not as defined by Mr. Owen or Messrs. Hall and Whitfield.
Ptychoparia Emmrichi, Barr. (Syst. Silur de Boheme. 1, p. 428, plate ii. Figs. 2-U), the second species arranged under the genus by Mr. Corda, diifei's in having the central portion of th ' head between the sutures in
front of the eyes narrower tlian in /'. striata, a feature quite prominent in the specieHfrom the Potsdiuu group in Wisconsin, etc. The pygidium is also more like that of P. Hnffuei, an«l the pleura have less angular extremities. If the student ^vill compare hg. 4, i)hite ii (Syst. Silur. de Bohdmo, vol. i, 1852), P. Emmrkhi, witli llg. 7 of plate xiii of the same work, I think that he will scarcely wish to place the two species in two subgeneric groups. If not, there appears to he no other way but to place Crepicephalus as a synonym of Ptychoparia for all species except P. {CrcpivephaluH) lowemis, where it may be used as a subgenus on account of the peculiar pygidiunt. The genus Loganellus 1 )evine (Geol. Canada, Pal. Foss., vol. i, p. 200), is of the same type as Ptychoparia tJmmriohi, and is considered by Messrs. Hall and VVhittield as identical with Oreciphalus = Ptychoparia Hayuti. Solenopleura Angeliu (Pal. Scan., ]>. 26) and Liostracus Angeliu each ajiproach this group. Liostracus represents the forms with the glabella devoid of furrows and the presence of ocular ridges on the fixed cheeks, and is a convenient subgeneric group. Solenopleura a])pears to be of the sajiie character as many of the species placed under the genus Batiiyurus by Mr. Billings, and 1 think can be used for such forms as Bathyurus gregarius, Billings (Pal. Fobs., vol. i, p. 363), and nearly all the species referred to the genus Bathyurus from the Cambrian. The figure of the type species of Solenopleura is copied on plate vi, ftg. 3.
Description. — " Head without movable cheeks, of moderate size, depressed convex, slightly arched in front, where the width is considerably less than behind; length about equal to breadtii in fron.t.
" Glabella ovate conical, sides straight, and doiyai iurruws so inclined as to meet if produced iu middle part of anterior ma'ff'j ; very convex; more elevated in the middle ; posterior furrows reachisig about one-third of the way across the glabella, directed strongly backwards, and reaching nearly to the base of the glabella ; middle furrows less distinctly marked, short, not so oblique as first ; anterior very short, appearing only as little pits or depressions on the sides of the glabella.
♦' Occipital ring narrow, convex, widest in the middle, narrowing towards the sides, which are turned forward, giving to it a crescent shape. Occipital furrow deep and wMI develoi)ed, widest in the middle, where it slightly impresses the base of the glabella ; narrow and slightly bent forward at the ends. Tiie ring bears a little, short, conical, tubercle-like spine in the middle, directed slightly backwards.
"Fixod clieckH, frontal limboni'tliird to oue-fourth of whole length of head, with » narrow, high, convex border, inside of which is a modorat«'I.v deep furrow ; cheek-lobes (lepressed, convex, meeting in front, risiiij,' abrnplly from the deep dorsal furrow, on the borders of which they reach their greatest elevation, which, however, is not equal to that of glabella, and sloping thence roundly towards the sides and IVoiit. 'flie posterior limb bears a deep, wide, airrow, which widens somewliat near extremity. The marginal fold is very narrow and of httle prominence, and widens a little in the outer half. The posterior margin bendssilightly backwards at extremity of limb, which is rounded."
On <'om|)aring the typo spetsimeus of P. Itohhi and P. formoaus^ and also a number of specimens of P. Robbi, I am unable to obtain gooil specific diflerences between them. The range of variation is slight and the two extremes are intimately united by specimens possessing the ciiaracters of each in a more or less fully developed condition. P.forntoum appears to have been founded on compressed specimens of P. liohhL
The representative type of P. liobbi occurs in the Menevian of Wales as the very closely related species Pttjehoparia (=Conocoryphe) applaluita, Salter (Quart. Jour. Geol. Soc, vol. xxv, p. 53, pi. xxv, figs. 1, L*, 4, 5). In Ptychoparia { = Solenopleura) cristata, Linuarssou (Afdrag ur Geol. Foreniugens, i Stockholm Fiirhandl. 1877, N:o. 40, Band, iii, N:o. 12, p. 370), from the Paradoxides beds of Sweden, we find an allied si)eciea, hiuI Mr. Linuarssou compares it with P. Emmrichi, the nearest represem.itive of the type in Bohemia.
Conovephalites ouangondianus, Hartt, 1HG8, Acadian Geology, Dawson, 2cl ed., p. 651. Description. — " Head without movable cheeks ; strongly convex in outline, somewhat subangular in front ; much narrower iu front than ht'hind, where width is greater than the length ; width in front nearly oqual to length ; anterior margin wide, with a strong fold, whose axis is strongly inclined forwards, so that it presents a short, steep, convex sUipe forward, and a long, concave slope in the inner side, being much U'ss elevated than g'lbella or fixed cheeks. Glabella long, ovate-conical, nearly twice as wide posteriorly as in front ; very convex, slightly subanguhir at the middle ; sides straight, inclined to one another so as to meet in the nuddle of front margin if produced ; rounded in front ; casts sometimes showing three pairs of short, raised, transverse lines ou the sides of the glabella, occupying the position of the ordinary glabellar furrows ; of these the two posterior are directed obliquely backwards. In some specimens there seems to be a fourth pair in ad-
vauce of the other, represented by little tubercle-like processes situated on the side of the glabella in front, just where the sides curve to the front. Glabella very much more convex than fixed cheek. Occipital ring strongly arc)!ed upward, and separated from glabella by a wellmarked groovb ; middle of posterior margin produced backwards in a short conical spine. Fixed cheeks highest along dorsal furrow, towards which they pressed abrupt round slopes, while their general surface slopes gently and quite evenly towards front of sutures. The dorsal furrows are confluent in front with the flat margin, so that the cheeklobes do not meet in front. They are highest along the straight dorsal furrows, but where they bend to go round the anterior extremity of glabella, the cheek-lobes narrowing and curving towards each other, gradually sink away and disappear in the front flattened space. The ocular lobes are veiy well developed, forming subsemicircular lappetlike lobes, curved strongly upwards, and situated about opposite the center of the head. An ocular ridge, low and rounded, but very prominent, runs from anterior margin of ocular lobes, with a curve almost parallel with front margin of shield, but slightly divergent from it to the dorsal furrow, which it gains at a point considerably back of front of glabella, and where the straight part of the dorsal furrow bends to go round the front. Posterior limb short and broadly rounded. Postmarginal furrows less deep than dorsal ; wider ; margimd fold narrow and moderately p'^ominent ; shield strongly arched transversely ; surface smooth."
This species is more fully represented by the centnil portion of the head than any other in the collection. The range of variation appears to have been small originally, but the distortion by lateral and vertical compression gives it a variety of forms. Three of these are illustrated.
A small head that appears to be uncompressed looks very much like that of P. {Solenopleura) cristata, Linnarsson. (See dc-acription of F. Rohbi.) Mr. Hartt speaks of this species as rather uncommon at Ratclitt's Mill stream, but on examii>ing al? the duplicate material we tind upwards of forty specimens. From the character of many of the specimens it appears quite probable tljat some of this material was not be fore him when he wrote the notes on the species.
Description. — "Resembles C. ovangondiamim, but differs in wider head, more depressed ; anterior margin more broadly rounded, and border more strongly reflexed and elevated."
To me the distinctive (jharacter between this species and P. ouangon(liana is in the form of the glabella. Compression and distortion may give the depressed broader form and reflexed rim, but not entirely the subquadrate glabella, that appears to be a feature of original varietal importance. With a large series of specimens of this form showing its variations, the tendency will be to deprive it even of a varietal name and unite it directly with P. Ouangondiana.
Description. — "Head minute, transversely oblong, twice as long, slightly curved in front, straight behind, very flat ; a narrow elevated fold, convex in front, concave behind, and somewhat inclined backward, goes round the margin."
There appears to be but one specimen representing this species in the collection. The strongly-marked subquadrate glabella distinguishes it at once from the associated species except P. ouangondianus, var. aurora, from which it is Si^arcely separated by the character of the frontal rim and the stronger ocular ridges. The entire length of the head is but two millimeters.
Description, — " The head-shield of this species without movable chee'ko is of medium size, length about equal to breadth in front, or to twotbirds width behind j margin arched moderately in front, with a rather wide, low border fold, widest in front, narrowing toward the sides, separated from the rest of t!ie head by a shallow groove. Glabella long, ovate, conical, or cyliudrico-conical, extremely convex, wider behind than in front, where it ii^ rounded. The sides are straight, and so inclined to one another as to meet, if produced, at a distance in advance of margin in front ab' .it eq*' . o the distance of that liiie from glabella. The glabella is flattened on the sides and never regularly convex. There are three pairs of furrows, which lightly impress the sides of the glabella, and of which traces are not always distinctly preserved, and they are apt to be otcn best in slightly distorted specimens. Dorsal furrow narrow, deep, and sharply cut ; occipital ring widest in the middle, narrowed from behind at the sides, separated from glabella by a
distinct furrow. Bears in the middle a minute tubercular spiue pointing upwards Fixed cheeks strongly convex, but much less so than the glabella, meeting in front with abrupt slopes t<oward dorsal and posterior marginal furrows, bat with gentle rounded slopes toward sides and anterior groove. Ocular ridges, marked as lightly raised lines, originating at the dorsal furrow some distance behind the front of the glabella, and rising obliquely upwards and backwards to ocular lobes which are small and semi-lunar, folded considerably upwards, and are sjjiated just opposite middle of head; width between ocular lobes about equal to the width in front. Behind the eye the suture describes a long open sigmoid curve, which is continued inward somewhat so as to give the limb a rounded outline, and make the cheek here about onethird wider than at the eye. Posterior margin of cheeks with a slight fold, more prominent in the middle ; outer half of this margin is arched backwards. Whole head arched slightly forward vertically."
The relations of this species are with both P. Eobbi and P. Ouangondiana. From the former, the character of the frontal rim and the more elongate glabella serves to separate it, and from the latter the rounded rim-like frontal border instead of the broader flattened margin. The relations of P. Orestes and P. Ouangondiana are very close.
Specimen No. 59 is recorded in M. Hartt's list as Gonocephalites Halli, and that name is scratched ou the slate besidn the specimen. The figure in the Acadian Geology (Fig. 227) was certainly not drawn from this specimen, but the description appears to have been.
Descrijition. — " Well separated from all others bj- its very convex, narrow, and long glabella, ovate, or cylindroconical, as well as by its strongly-rounded sub-angular outline in front, and by its peculiar anterior marginal fold."
I have studied the type specimens and also the representations of P. Orestes and Mr. Hartt's 6'. Halli in the collection, and it appears to be impossible to find characters that are persistent in a series of individuals to separate them as distinct species.
Description. — " Differs from the last (Conocephalitea Aurora) and also from C. Ouangondianum in the front margin being broad and flat, and bordered by a low, narrow, flattened fold or ridge, &c. Glabella in tiie vast has tliree pairs of very short raised lines on the sides."
ten are very close, and I had placed it with C. HalU under P. Orestes iu a preliminary study of the species. The material is so fragmentary and poorly preserved that it is dif&cult to satisfactorily determine the limits of many of the species.
Description. — " Minute, j^labella ovate-conical, truncate at base, rounded ill front, where it is about half as wide as at occipital furrow, slightly contracted behind, length about equal to width at occipital furrow, strongly de])r'\ispd convex, more elevated at base than at front, and higher ala- • ^Im "sed cheeks ; aspect varies with state of preservation of specii»^!7 > \: : . i,e, rounded, convex, or concave; the middle seemH to be incliuv j t< project back slightly over the occipital furrow, slopes abruptly to occipital furrow, which is moderately deep, wide, and narrowed, and slightly inclined forward at the ends, where it terminates abruptly ; bounding groove deeper than other grooves in head ; occipital ring projecting backward bodily beyond higher margin, with the axis of its fold Inclined more or less backwai'd, and produced in the middle into a short conical backward inclined spine ; anterior limb regularly arched, as if the outlines of the complete head were semicircular.
"Fixed cheeks, anterior border broad, fiat concave, rising more or less abruptly to a sharp, thin, marginal fold; width between anterior extremities of cheek sutures "qua! to or about twice width of glabella at base. Cheek-lobes but si ' - ii !y convex, and much more depressed than the i;labella. Ocular ri<:'.>8 rry distinct, thin, sharj), elevated ridges, that begin about inn'ci ci .» cr' oheek-lobes, just behind rounded front of glabella, runoutwan a , 'jacizward at an angle of 60° to 65° to the anteroposterior diameter. ^ o' me at first straight, but soon begin to bend backward more and more abruptly, forming st fragment of a s])ii'al, their extremities being slightly directed inwards. The width between the ocular lobes is about equal to twice the ler.gth of the glabella. The ocular ridges are inclined outwards and forwards. Another ridge of the same appearance begins a very sh«/rt distance behind the origin of the former, and on the very margin of the cheek-lobes, and, diverging from the margin nej-; ' opposite to the base of the glabella, bends off abruptly along the ,)' r< \"')r margin of the cheek-lobe, describing a curve, whose convexity lircctod backwards. This ridge terminates considerably outside of the ocular lobe, ..t a point distant from the ^labe'la about equal to half the width of the latter at its base. This xidge '\:^ usually found incliued in the opposite direction to the former,
viz, inward and backward. Posterior margin of fixed cheeks moderately and regnlarly S curved, the inner halves carving forwards, the outer halves backwards, with a marginal fold most elevated in the middle, but much less so than the ridges of the cheek-lobe or the anterior fold. This fold becomes double at about the middle, by thie appearance of a groove running along its summit, and it appears to run out before reaching the lateral suture. The width between the posterior extremities of cheek sutures is considerably greater than between the anterior extremities or between the ocular lobes. Glabella without furrows."
Highest at middle of base and sloping . a regular curve toward the front. Traces of two pairs of glabellar lurrows on the sides. Occipital furrow deep and concave. Occipital ring with straight parallel margins, narrow, with a short conical spine directed upward."
The type specimen, No. 341, of Mr. Hartt's list, shows Tae same ocular ridges as in P. tener and also the same ridges on the inner side of the palpebral lobes. The specimen has been compressed so as to shorten and widen the glal>ella, and give it the characters mentioned by Mr. Hnrtt. On the evidence of the material in the collection, it does not ai)pear to represent a distinct species from P. tener.
FAUNA OF THE BRAINTREB ARGIIililTES.
Wishing to examine typical si)eciinen8 of Paradoxides Harlani, the writer visited Boston, and through tl»e kindness of Mr. Alpheus Hyatt, curator in charge of the collections of the Boston Society of Natural History, he not only obtained Jiccess to the collection from the Braintroe argillites, but the loan of such specimens as were wished for study and illustration. Mr. Alexander Agassiz also gave permission to use material in the collections of the Museum of Comparative Zoology, and Mr. N. S. Shaler pV'.ced his private collection at the writer's disposal. It is owing to these favorable conditions that I am able to present at tills time illustrations .and descriptions of the fauna of the Braintree argillites.
The first notice of the presence of fossils in the patches of argillite associated with the Quincy granite in the north end of the town of Braintree, IMass., was by the late Mr. William B. Eogers, who called the attention of the members of the Boston Society of Natural History to it when exhibiting specimens of a large trilobite i'onnd at Hayward's quarry (Proc. Boston Soc. Nat. Hist., vol. vi, p. 27, 185G). SubseI quently Mr. JRogers traced the history of the trilobite described by Mr. Jacob Green as Pnradoxides Harlani, in 1834, and showed quite conclusively that it came from Hayward's quarry and was identical with the species found there. Mr. Henry D. Kogers published the best figure of the species yet given, with remarks on its discovery, «&c. (Geol. Surv. [Penii., vol. ii, p. 816, 1858).
Numerous collectors obtained specimens of Paradoxides Harlani, but I it is not until 1801 that we find any notice of other species. Mr. Albert Ordway then states that lie had found a fragment of a trilobite similar to that described in the Paradoxides beds of Newfoundland, in association with Paradoxides Bcnnetti, and which he referred to the genus Elllipsocephalus. He also mentions the discovery of " a distinct fucoidal [impression which shows three branches, each about 4 inches long, but not sufficiently well marked to aflbrd any evidence with regard to its nature" (Proc. Boston Soc. Nat. Hist., vol. viii, p. 6, 1862). The small jtrilobito is probably the same as that subsequently described by Mr. R. |P. Whitfield as Arionellus = Agraulos quadrangularis (Bull. Amer. Mus. li^^at. Hist., vol. i, p. 147, 1884). Mr. Ordway also published a figure of Itlie head of Paradoxides Harlani, when comparing that species with iPamdo.vides spinosus, Boeck, which Mr. Barrande considered as identical pith P. Harlani (Bull. Geol. Soc. France, vol. xvii, pp. 545-548, 1860). In the year 1803 a restored figure of Paradoxides Harlani, by Mr. F.
B. Meek, was published iu Diiiia's IMimual of Geology and repeated in each subsequent edition of the Mauual. This very well represents the general characters of the species.
The publication of the second described species by Mr. Whitfield gives a stronger interest to the fauna, which is now increased by the addition of another species of trilobite, Ptychoparia Eogersi, and a si)ecies of Pteropod, Jlyolithes Shaleri.
In seeking for a fauna in the Cambrian system of North America to compare with that of the Braintree argillites, we are at once directed to the Paradoxides beds of Newfoundland by the almost perfect identity of the leatling type of each locality, Paradoxides Harlani and P. Bennetti. 1 think it has yet to be decided that the two are distinct species. ByoHthes excellens, Billings y"al. Foss., vol. ii, pt. 1, p. 70, 1874), is very closely related to JT. Shaleri, more so than to any other American species, and Agraulos sociaMs, Billings {loc. cit, p. 71), is of the same type as A. quadrangularis, Whitfield, as shown by figure 1 of plate vii. Ptychoparia Rogersi does not appear to be represented in the Newfoundlaud Paradoxides beds, unless it be by Ptychoparia (Solenopleura) communis, Billings {loc. cit., p. 72).
Mr. Barrande has shown the strong resemblance between Paradoxides spinosus, of the Bohemian Basin, and P. Harlani; and the Paradoxides beds of Sweden, Bohemia, Wales, Newfoundland, and Braintree have frequently been correlated in a general manner by authors.
i'orm an elongate triangular pyramid, slightly arching towards the dorsal side and expanding regularly from the apex towards the aperture. Transverse section midway of the length, semielliptical, with a width twice as great as the height ; the lateral angles acute. Ventral face gently convex transversely, curving slightly longitudinally. Dorsal face strongly convex, and showing a slight tendency to become angular at the center, a little concave longitudinally. From the direc tion of the surface lines the aperture sippears to have been oblique. Opercolum unknown. Surface marked by lines of growth thsit on the| dorsal side are nearly transverse, and on the ventral side arched for ward ; traces of fine longitudinal lines are shown in the matrix of the | ventral side.
Description. — " The contour of the buckler in this species cannot be satisfactorily determined from our present specimen ; the anterior and posterior parts of it are well defined, but the cheeks on each side are either mutilated or obscured. The front is very much elevated above the surface of the cheeks. It rises a little before the anterior edge of the buckler, is rounded in front, and gradually tapers towards the middle lobe of the abdomen, with which it forms a regular continuation. On its posterior surface there are three transverse furrows ; the upper one crosses it a little obliquely, and there is on each side above a considerable protuberance. The cheeks were, no doubt, in the form of spherical triangles, but whether the outer angles terminated in acute prolongations cannot, from our specimen, be determined. The organs of vision appear to be entirely wanting. There are two shallow depressions on each side of the cheeks, commencing near the protuberances on tlie front, and running towards the lateral edges of the buckler. The posterior border of the buckler, where it joins the lobes of the abdomen, is marked by a transverse groove, nearly continuous with the lower transverse furrow on the front ; this groove at its commencement appears to bifurcate outwards. The abdomen and tail cannot be distinguished from each other. There are seventeen distinct articulations in both. The middle lobe is very convex, and is separated from the lateral ones by a deep channel ; it gradually tapers to an obtuse tip. In our specimen there is a small part of the tail of another trilobite deposited in this place, which at first sight api)ears to be a dislocated fragment
of jiir animal. The lateral lobes are flattened ; the costal arches arc very distinct near their insertion, and for about half their length, but towards their free extremities tliey are a good deal obliterated. There appears to have been a delicate membranaceous prolongation for a considerable distance beyond the solid portion of each rib. This organization is very apparent on the costal arches of the tail. There is a deep groove running obliqnely over the upper surface of each rib. Length of the fossil about 9 inches ; breadth, about 4 inches."
Mr. Green did not know the true locality of the specimen sent to hiin by Mr. Harlan, and it was not until twenty-two years after that Mr. W. B. Kogers announced the discovery of ai)eciraeu8 of the same species at South Braintree, near Boston, Mass., identifying the locality of the specimen used by Mr. Green in his original description. The description is unaccompanied by figures, but fortunately Mr. Green made numerous casts of the type, one of which is now before me. It is the narrow form of the species, measuring 22"'" in length by about 14°'" in width across the back of the head, and 12"'" across the wi«lest portion of the thorax. The palpebral lobes and movable cheeks are broken away, also the posterior segment of the thorax and the i)ygidium is displaced. Mr. Green describes the species as having 17 thoracic segments ; but in a very fiue specimen now in the collection of the Boston Society of ¥ tural History, 18 segments are shown between the head and pygidium ; and Mr. Henry D. Eogers gives a very perfect figure with 18 thoracic segments.
Mr. Ordway, in making a comparison between that species and the Bohemian P. spinosus (Proc. Boston Soc. Nat. Hist., vol. viii, p. 3), gives an outline figure of the head of P. Harlani, which is evidently a restored figure made up from fragments.
At the request of Mr. J . D. Dana, Mr. F. B. Meek drew a figure of P. Harlani for the Manual of Geology', from more or less fragmentary specimens in Mr. Dana's collection. This is one of the best, but not the best (see Rogers's figure), representations of the species yet published ; but in the presence of 19 segments in the thorax, and the short extension of the posterior pleurfe and other details, it varies from specimens before us. There is considerable variation in the species in the relative length and breadth of individufils. In a form similar to the type, the length is 21"™, and the greatest breadth of the thorax 10"". In two broad specimens the length is 25'"" and SS""' ; the breadth of the thorax 1C«'° and 20°°'., respectively. This variation is also shown in the pygidium, as may be seen by comparing figs, 16, c, d of plate viii. In the head the greatest variation is seen in the contour of the frontal margin and the gradual development of the frontal limb and rim. On the small specimens the frontal limb is very short and more or less rounded. With the in crease in size, the space between the glabella and the marginal rim increases in width, and the latter broadens and flattens out. Our information respecting the posterolateral spines of the head is limited. On the j narrow form, fig. 1, plate ix, they extend back to a point opposite the |
fourteenth thoracic segment ; and the movable cheek, fig. 3, plate vii, Hhows a long, well-developed spine. There is a limited range of variatiou iu the extension ot the pleuree of the thoracic segments, but the material for study is too limited to say what value may be placed upon it. In reviewing all the variations, I do not think that more than one species is indicated. A narrow and broad variety might be designated if thought desirable.
Of American species of the genus Paradoxides, P. Bennetti, Salter (Quart. Journ. Geol. Soc, vol. xv, p. 552, fig. 1, 1859), from Newfoundland, is the most nearly related. The figure accompanying Mr. Salter's description appears to have been taken from a distorted specimen, as the two specimens now before me, although imperfect, show aform very similar to that of P. Harlani.
Mr. Ordway has described the differences between P. Harlani, Green, aud P. Hpinosus, Boeck (Proc. Boston Soc. Nat. Hist., vol. viii, pp. 1-5, 18G1), and from my own observations and . comparisons I cannot but agree with Mr. Ordway that the two species are represented. Mr. Barraiide considered P. spinosua and P. Harlani as one species (Bull. Geol. Soc, France, vol. xvii, pp. 545-547, 1860). Mr. Barraude had the cast of the imperfect specimen described by Mr. Green to compare with specimeus of P. spinosua, and photographs of three specimens sent to him by Mr. W. B. Rogers. The two species are, however, very closely related.
two specimens showing portions of the thorax.
Glabella cylindro-conical, rounding rather abruptly iu front, posterior pair of glabellar furrows very faintly shown in one specimen ; dorsal furrow strongly defined; occipital furrow rounded, well marked and extending out across the flixed cheeks; occipital ring rather narrow, rising at the center and extending backwards in a short, strong spine ; fixed cheeks of medium width, moderately convex, and sloping forward to unite with the frontal limb ; ocular ridges shown only on one specimen ; starting a little back of the anterior end of the glabella, they extend obliquely backward to the small palpebral lobe; frontal limb rather narrow; it curves downward for a short distance in front of the glabella aud then up to the frontal rim. The facial sutures cut the anterior margin so as to leave a narrow frontal limb, and then extend obliquely outward and backward to the palpebral lobe;_ back of this they extend obliquely outward to the posterior margin of the head.
Thorax formed of well marked, strongly trilobed, narrow segments; the axial lobe about one-third of the entire width anteriorly, and tapering rather rapidly backward; pleural grooves very narrow. Number of segments in the thorax unknown.
uncertain. It is apparently roughened or grauulose.
Owing to the lateral compression of the specimen illustrated, the form of the glabella is too elongate. In hopes of getting better specimens the further illustration of the species is deferred.
The specific name is given in honor of Mr. W. B. Bogers, the distinguished geologist, who took so strong an interest in the discovery of the Braintree paradoxides beds in 1856.
fig. 8.
Description. — " Known only by the glabella and fixed cheeks, which are of small size, and as united are subquadrangular in form and depressed convex. Glabella quadrangular a little narrower in front than at the occipital line, squarely truncate in front and destitute of any appearance of glabellar furrows. Dorsal furrows bounding the glabella, deeply marked. Fixed cheeks about half as wide as the glabella, moderately convex in the middle. Frontal limb about as wide as the fixed cheeks, convex on the surface and strongly arched on the front border; no marginal rim exists. Palpebral lobes, one of which is visible, minute, and but slightly raised above the general surface of the fixed cheek adjacent. Occipital ring narrow. General surface smooth. This species is so entirely distinct in its quadrangular gla belli that there is no possibility of confounding it with any other American species of the genus."
We have two specimens of this species showing the central portions of the head and fixed cheeks. The glabella is more elongate and less quadrangular than in the type specimen which appears to be longitudi nally compressed, and also without the occipital ring and the postero lateral portions of the fixed cheeks. Restoring these parts in outline on the figure given by Mr. Whitfield, leads to the conclusion that "ve have but one species represented by specimens, varying considerably owing to their condition of preservation. The largest head is from the collection of Mr. N. S. Shaler, and measures 18"'"' in length. A smaller] head in the collection of the Boston Society of Natural History is 9" in length, and shows a small spine on the center of the occipital ring.
The first notice of this species is by Mr. Albert Ordway (Proc. Boston Soc. Nat. Hist., vol. viii, p. 6, 1861), v 'lere he refers it to the geiiut) Ellil)socephalus, but does not propose ,i jpecittc name. Mr. J. Marcou had ii specimen in his collection for many jears, but it does not appear to have been h )ticed until studied by Mr. Whitfield.
Genus PBOTOOABIS, n. gen.
Garapace without evidence of a dorsal sutore, rounded on the dorsal line, and bent downward on the sides ; without any rostrum. Body many -jointed — 31 segments extending out from beneath the carapace; the last segment broader than the preceding, and terminating in two spines. Type Protocaris Marahi.
In comparing Protocaris (P. Marahi) with Hymenocaris (if. vermicatida) (Salter, 1852. Bep. Br^c. Assi c, pt. 2, Notices and Abstracts, p, 58; Mem. Geol. Surv. Gt. Brit., vol. iii, y. 293, plate ii, figs. 1-4; plate v., fig. 25, 1866) we find that in tlie simple, iL>ent or folded eyeless shield or carapace they are closely related, but in the structure of the body they di£fer materially. Hymenocaris has, in one instance, 9 strong segments shown in its more elongate body, the terminal one ending in three pairs of spines ; usually 6 or 7 segments are seen, 8 or 9 are less frequent (Brit. Assoc. Bep. 1883, p. 219). Protocaris has 30 narrow segments, a large terminal segment or telson with two rather strong caudal or terminal spines.
The specimen on (^hich the genus and species is founded is compressed between the laminsB of the slate so that the entire outline of I the carapace is shown and the body is widened out. As flattened the | carapace is rounded, quadrangular in outline, with a more or less dis tinctly defined marginal rim all around. The general surface appears | to have been smooth. No evidence of eyes.
The body projecting beyond the carapace is about two-thirds as long | as the carapace, narrows posteriorly, and is made up of numerous narrow segments, each about one-third of a millimeter in breadth ; the last I segment or telson, which is 2.5°"^ long, supports two caudal spines? or 8°"" in length; 30 segments appear between the posterior edge of J the carapace and the telson; the segments appear to have been I smooth and without a spinose or crenulated posterior margin ; the tel I son and caudal spines also appear to have been smooth and withontj ornamentation.
NEW GENIJ8 ANU srECItS OF PHYLLOPODA,
IHmennionii. — Total It'iigtli, 42"""; length of carnimce, 21""" ; width, 20111111 . length of body, !/>"'"', t'xt!lu8iv« of ciiudal spines; width of body, where it passes beneath the carapace, 10"'"' ; at tolson, 4""°.
Eteminicus 10, 11, ST
Eteminicus, var. breviatus. . .10, 11, 27 Eteminicus, var. Mali'-.itus. . . 10 11, 27 Eteminicus, var. pontiflci'Ws .10, li, 27 Eteminicus, var. Quacoonais. 10, 11 Eteminicus, var. suricoides . .10, 11, 27
Pig. 1. Pabadoxides Harlani
1, A large individual preserving the body and parts of the head. The light colored portions are restored and the pygidinm, which is pushed a little out of position, replaced. The speoinien is from the collection of the Boston Society of Natural History.
Pig. 1. Pkotocaris Marshi
1 . View of the type specimen as it occcrs flattened ont on the shale. The body rings are more obscured in the anterior portion of the body than as represented in the figure. Enlarged to two diameters.
' ' The publicationa of the Oeological Surrey shall consist of the annual report of operations, geological and economic maps illnstrating the resources and classifications of the lands and reports upon general and economic geology and paleontology. The annual report of operations of the Oeological Surrey shall accompany the annual report of the Seorotary of the Interior. All special memoirs and reporta of said Survey shall be issued in uniform quarto series if deemed necessary by the director, but otherwise in ordinary octavos. Three thousand copies of each shall be published for scientific exchanges and for sale at the price of publication ; and all literary and cartographic materials received in exchange shall be the property of the United tjtates and form a part of the library of the organisation : And the money resulting from the sale of such pnblicati ons shall be covered into the Treasury of the United States."
by Congress :
That whenever any document or report shall be ordered printed by Congress, there shall be printed in addition to the number in each case stated, the " usual number" [1,900] of copies tor binding and distribution among those entitled to receive thiim.
I'nder these general laws it will be seen that none r-f the survey publications are furnished to it for ;:ratuitous distribution. The 3,000 copies of tho annual report are distributed through the document rmnii) of Congress. The 1,900 copies of each of the pnblicationH are distributed to the officers of the legislative and executive departments and to stated depositories throughout the United States.
Except, therefore, in those cases where an extra number of auy publication is supplied to this office hy special resolution of Congress, as has been done in the case of the second, third, fourth, and fifth annual reports, or where a number has been ordered for its use by the Secretary of the Interior, as in ilie case of Williams's Mineral Resources, the survey hasnocopiesof any of its publications for grrtuitoas distribution.
VI. Older Mesozoic Flora of Virginia, by Prof. Wm. M. Fontaine. Published.
VII. Silver-lead Deposito of Eureka, Nevada, by Joseph S. Curtis. Published. VIU. Paleontology of the Eureka District, Nevada, by Charles D. Walcott In press. IX. Bracbiopoda and Lamellibranchiato of the Green Marls and Clays of Kew Jersey, by B. P.
do not properly come under the heads of Annual Rbpobtb or Monoobapub.
Each of these Bulletins will contain but one paper, aud be complete in itself. They will, however, be numbered in a continuous series, and will in time bo united into volun. >a of convenient size. To facilitate this, each Bulletin will have two paginations, one proper to itself, and one which bolonga to it aa part of the volume.
A fourth series of publications having special reference to the mineral resonrcea of the United States I is contemplated. Of that series the first has been published, viz : Mineral Resources of tLe United | States, by Albert Williams, Jr. 1883. 8°. xvii, 818 pp. Price 50 cents.
| 22,944 | common-pile/pre_1929_books_filtered | cihm_14746 | public_library | public_library_1929_dolma-0014.json.gz:273 | https://archive.org/download/cihm_14746/cihm_14746_djvu.txt |
b6CXAGwTPLNcGhiv | 3.15: Chest and Wall Cabinet | 3.15: Chest and Wall Cabinet
|
Wall Cabinet
Norwegian-American Olin Ruste, 1965 Wood (pine) Little Norway Collection, Gift of Scott & Jennifer Winner MHAHS 2015.021.0010 |
|
Chest
Norwegian-American Olin Ruste, 1968 Wood (pine) Little Norway Collection, Gift of Scott & Jennifer Winner MHAHS 2014.050.0082 |
Retired farmer Olin Ruste used his woodworking skills to explore his Norwegian heritage. In the mid- to late-1960s, Ruste constructed and decorated in carved relief this wall cabinet and chest, both for his own personal use. The wall cabinet proudly displays his name carved in the lower front panel, while the chest incorporates not only the Norwegian Coat of Arms, but also the motif from the main building at Little Norway where he acted as a guide. After honing his skills, Ruste went on to successfully tackle the construction of a full-size Norwegian stubur , or storehouse, at Little Norway in 1969. | 192 | common-pile/libretexts_filtered | https://human.libretexts.org/Bookshelves/Art/Book%3A_Creators_Collectors_and_Communities_(Martin)/03%3A_Heritage_Memorialized/03.15%3A_Chest_and_Wall_Cabinet | libretexts | libretexts-0000.json.gz:1535 | https://human.libretexts.org/Bookshelves/Art/Book%3A_Creators_Collectors_and_Communities_(Martin)/03%3A_Heritage_Memorialized/03.15%3A_Chest_and_Wall_Cabinet |
wWsIBMR1W0AMzxWI | 12.5E: Exercises | 12.5E: Exercises
Practice Makes Perfect
In the following exercises, expand each binomial using Pascal’s Triangle.
- \((x+y)^{4}\)
- \((a+b)^{8}\)
- \((m+n)^{10}\)
- \((p+q)^{9}\)
- \((x-y)^{5}\)
- \((a-b)^{6}\)
- \((x+4)^{4}\)
- \((x+5)^{3}\)
- \((y+2)^{5}\)
- \((y+1)^{7}\)
- \((z-3)^{5}\)
- \((z-2)^{6}\)
- \((4x-1)^{3}\)
- \((3x-1)^{5}\)
- \((3 x-4)^{4}\)
- \((3 x-5)^{3}\)
- \((2 x+3 y)^{3}\)
- \((3 x+5 y)^{3}\)
- Answer
-
2. \(\begin{array}{l}{a^{8}+8 a^{7} b+28 a^{6} b^{2}+56 a^{5} b^{3}} {+70 a^{4} b^{4}+56 a^{3} b^{5}+28 a^{2} b^{6}} {+8 a b^{7}+b^{8}}\end{array}\)
4. \(\begin{array}{l}{p^{9}+9 p^{8} q+36 p^{7} q^{2}+84 p^{6} q^{3}} {+126 p^{5} q^{4}+126 p^{4} q^{5}+84 p^{3} q^{6}} {+36 p^{2} q^{7}+9 p q^{8}+q^{9}}\end{array}\)
6. \(\begin{array}{l}{a^{6}-6 a^{5} b+15 a^{4} b^{2}-20 a^{3} b^{3}} {+15 a^{2} b^{4}-6 a b^{5}+b^{6}}\end{array}\)
8. \(x^{3}+15 x^{2}+75 x+125\)
10. \(\begin{array}{l}{y^{7}+7 y^{6}+21 y^{5}+35 y^{4}+35 y^{3}} {+21 y^{2}+7 y+1}\end{array}\)
12. \(\begin{array}{l}{z^{6}-12 z^{5}+60 z^{4}-160 z^{3}+240 z^{2}} \\ {-192 z+64}\end{array}\)
14. \(\begin{array}{l}{243 x^{5}-405 x^{4}+270 x^{3}-90 x^{2}} {+15 x-1}\end{array}\)
16. \(27 x^{3}-135 x^{2}+225 x-125\)
18. \(27 x^{3}+135 x^{2} y+225 x y^{2}+125 y^{3}\)
-
- \(\left( \begin{array}{l}{8} \\ {1}\end{array}\right)\)
- \(\left( \begin{array}{l}{10} \\ {10}\end{array}\right)\)
- \(\left( \begin{array}{l}{6} \\ {0}\end{array}\right)\)
- \(\left( \begin{array}{l}{9} \\ {3}\end{array}\right)\)
-
- \(\left( \begin{array}{l}{7} \\ {1}\end{array}\right)\)
- \(\left( \begin{array}{l}{4} \\ {4}\end{array}\right)\)
- \(\left( \begin{array}{l}{3} \\ {0}\end{array}\right)\)
- \(\left( \begin{array}{l}{5} \\ {3}\end{array}\right)\)
-
- \(\left( \begin{array}{l}{3} \\ {1}\end{array}\right)\)
- \(\left( \begin{array}{l}{9} \\ {9}\end{array}\right)\)
- \(\left( \begin{array}{l}{7} \\ {0}\end{array}\right)\)
- \(\left( \begin{array}{l}{5} \\ {3}\end{array}\right)\)
-
- \(\left( \begin{array}{l}{4} \\ {1}\end{array}\right)\)
- \(\left( \begin{array}{l}{5} \\ {5}\end{array}\right)\)
- \(\left( \begin{array}{l}{8} \\ {0}\end{array}\right)\)
- \(\left( \begin{array}{l}{11} \\ {9}\end{array}\right)\)
- Answer
-
2.
- \(7\)
- \(1\)
- \(1\)
- \(45\)
4.
- \(4\)
- \(1\)
- \(1\)
- \(55\)
In the following exercises, expand each binomial.
- \((x+y)^{3}\)
- \((m+n)^{5}\)
- \((a+b)^{6}\)
- \((s+t)^{7}\)
- \((x-2)^{4}\)
- \((y-3)^{4}\)
- \((p-1)^{5}\)
- \((q-4)^{3}\)
- \((3x-y)^{5}\)
- \((5x-2y)^{4}\)
- \((2x+5y)^{4}\)
- \((3x+4y)^{5}\)
- Answer
-
2. \(\begin{array}{l}{m^{5}+5 m^{4} n+10 m^{3} n^{2}+10 m^{2} n^{3}} {+5 m n^{4}+n^{5}}\end{array}\)
4. \(\begin{array}{l}{s^{7}+7 s^{6} t+21 s^{5} t^{2}+35 s^{4} t^{3}} {+35 s^{3} t^{4}+21 s^{2} t^{5}+7 s t^{6}+t^{7}}\end{array}\)
6. \(y^{4}-12 y^{3}+54 y^{2}-108 y+81\)
8. \(q^{3}-12 q^{2}+48 q-64\)
10. \(\begin{array}{l}{625 x^{4}-1000 x^{3} y+600 x^{2} y^{2}} {-160 x y^{3}+16 y^{4}}\end{array}\)
12. \(\begin{array}{l}{243 x^{5}+1620 x^{4} y+4320 x^{3} y^{2}} {+5760 x^{2} y^{3}+3840 x y^{4}+1024 y^{5}}\end{array}\)
In the following exercises, find the indicated term in the expansion of the binomial.
- Sixth term of \((x+y)^{10}\)
- Fifth term of \((a+b)^{9}\)
- Fourth term of \((x-y)^{8}\)
- Seventh term of \((x-y)^{11}\)
- Answer
-
2. \(126a^{5} b^{4}\)
4. \(462x^{5} y^{6}\)
In the following exercises, find the coefficient of the indicated term in the expansion of the binomial.
- \(y^{3}\) term of \((y+5)^{4}\)
- \(x^{6}\) term of \((x+2)^{8}\)
- \(x^{5}\) term of \((x-4)^{6}\)
- \(x^{7}\) term of \((x-3)^{9}\)
- \(a^{4} b^{2}\) term of \((2 a+b)^{6}\)
- \(p^{5} q^{4}\) term of \((3 p+q)^{9}\)
- Answer
-
2. \(112\)
4. \(324\)
6. \(30,618\)
- In your own words explain how to find the rows of the Pascal's Triangle. Write the first five rows of Pascal's Triangle.
- In your own words, explain the pattern of exponents for each variable in the expansion of.
- In your own words, explain the difference between \((a+b)^{n}\) and \((a-b)^{n}\).
- In your own words, explain how to find a specific term in the expansion of a binomial without expanding the whole thing. Use an example to help explain.
- Answer
-
2. Answers will vary
4. Answers will vary
Self Check
a. After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.
b. On a scale of 1-10, how would you rate your mastery of this section in light of your responses on the checklist? How can you improve this? | 773 | common-pile/libretexts_filtered | https://math.libretexts.org/Bookshelves/Algebra/Intermediate_Algebra_1e_(OpenStax)/12%3A_Sequences_Series_and_Binomial_Theorem/12.05%3A_Binomial_Theorem/12.5E%3A_Exercises | libretexts | libretexts-0000.json.gz:4883 | https://math.libretexts.org/Bookshelves/Algebra/Intermediate_Algebra_1e_(OpenStax)/12%3A_Sequences_Series_and_Binomial_Theorem/12.05%3A_Binomial_Theorem/12.5E%3A_Exercises |
yq7fHET-qymkUpBU | The chemistry of leather manufacture, by John Arthur Wilson. | Scientific and Technologic Monographs
By arrangement with the Interallied Conference of Pure and Applied Chemistry, which met in London and Brussels in July, 1919, the American Chemical Society was to undertake the production and publication of Scientific and Technologic Monographs on chemical subjects. At the same time it was agreed that the National Research Council, in codperation with the American Chemical Society and the American Physical Society, should undertake the production and publication of Critical Tables of Chemical and Physical Constants. The American Chemical Society and the National Research Council mutually agreed to care for these two fields of chemical development. The American Chemical Society named as Trustees, to make the necessary arrangements for the publication of the monographs, Charles L. Parsons, Secretary of the American Chemical Society, Washington, D. C.; John E. Teeple, Treasurer of the American Chemical Society, New York City; and Professor Gellert Alleman of Swarthmore College. The Trustees have arranged for the publication of the American Chemical Society series of (a) Scientific and (b) Technologic Monographs _ by the Chemical Catalog Company of New York City.
The Council, acting through the Committee on National Policy of the American Chemical Society, appointed the editors, named at the close of this introduction, to have charge of securing authors, and of considering critically the manuscripts prepared. The editors of each series will endeavor to select topics which are of current interest and authors who are recognized as authorities in their respective fields. The list of monographs thus far secured appears in the publisher’s own announcement elsewhere in this volume.
4 GENERAL INTRODUCTION
the fields covered by this development have been so varied that it is difficult for any individual to keep in touch with the progress in branches of science outside his own specialty. In spite of the facilities for the examination of the literature given by Chemical Abstracts and such compendia as Beilstein’s Handbuch der Organischen Chemie, Richter’s Lexikon, Ostwald’s Lehrbuch der Allgemeinen Chemie, Abegg’s and Gmelin-Kraut’s Handbuch der Anorganischen Chemie and the English and French Dictionaries of Chemistry, it often takes a ereat deal of time to coordinate the knowledge available upon a single topic. Consequently when men who have spent years in the study of important subjects are willing to codrdinate their knowledge and present it in concise, readable form, they perform a service of the highest value to their fellow chemists.
It was with a clear recognition of the usefulness of reviews of this character that a Committee of the American Chemical Society recommended the publication of the two series of monographs under the auspices of the Society.
Two rather distinct purposes are to be served by these monographs. The first purpose, whose fulfillment will probably render to chemists in general the most important service, is to present the knowledge available upon the chosen topic in a readable form, intelligible to those whose activities may be along a wholly different line. Many chemists fail to realize how closely their investigations may be connected with other work which on the surface appears far afield from their own. These monographs will enable such men to form closer contact with the work of chemists in other lines of research. The second purpose is to promote research in the branch of science covered by the monograph, by furnishing a well digested survey of the progress already made in that field and by pointing out directions in which investigation needs to be extended. To facilitate the attainment of this purpose, it is intended to include extended references to the literature, which will enable anyone interested to follow up the subject in more detail. If the literature is so voluminous that a complete bibliography is impracticable, a critical selection will be made of those papers which are most important. -
attempt to found an American chemical literature without primary
regard to commercial considerations. The success of the venture will depend in large part upon the measure of cooperation which can be secured in the preparation of books dealing adequately with topics of
Thyrozin. By E. C. Kendall. :
The Properties of Silica and the Silicates. By Robert B. Sosman. | Coal Carbonization. By Horace C. Porter. : The Corrosion of Alloys. By C. G. Fink. | Piezo-Chemistry. By L. H. Adams.
PREFACE
The chemistry of leather manufacture is progressing more rapidly now than at any previous time. Much of the earlier work fasled to recognize the existence of important variable factors and has been rendered obsolete by recent investigations carried out under more highly refined conditions. In preparing this monograph, it was found necessary, for the purpose of correlating existing data, to conduct many special investigations and these are being reported here for the first time. Advance information on investigations under way in other laboratories has been obtained, wherever possible, so that the presentation might be made reasonably complete to the close of the year 1922.
The literature pertaining to leather manufacture is so vast and the views expressed so numerous and divergent as to make an impersonal compilation of all published papers encyclopedic in size, bewildering to the average reader, and an undertaking of questionable value. In order to fulfill the first purpose of this series of monographs, namely, to present the knowledge available in a readable form, intelligible to those whose activities may be along a wholly different line, the author has felt compelled to present the subject from his own viewpoint, making no attempt to discuss views which, in his opinion, fail to contribute anything to the development of leather chemistry. In so doing, the author is fully aware that there are others who do not share his opinions of the relative merits of various views, but he can only admit his inability to present adequately views which appear to him unsound. But, ina field so vast, there is ample room for as many volumes as there may be sides to the question worthy of presentation and it is in the preparation of additional volumes that criticism of this attitude may find its best expression.
A considerable amount of space has been devoted to the histology of skin and to the physical chemistry of the proteins because of their fundamental bearing on the chemistry of leather manufacture. Descriptions of analytic methods and practical details of leather manufacture have been given only where they seemed necessary to make the subject clearer to chemists unfamiliar with tannery routine.
period of intimate association with Professor H. R. Procter, of the University of Leeds, England, who is affectionately known throughout the world as the “father of leather chemistry” and whose books on leather manufacture have ‘been the standard for the past thirty-five years.
In the preparation of sections and photomicrographs, valuable assistance was rendered by Mr. Guido Daub, whose painstaking efforts are largely responsible for the success of this phase of the work. The sections and specimens of human skin were procured from Professor T. H. Bast, of the University of Wisconsin. Professor Arthur W Thomas, of Columbia University, supplied the skins of guinea pigs and albino rats fixed in Erlicki’s fluid. Leathers from the hides of the hippopotamus, walrus, and camel were furnished by Professor Douglas McCandlish, of the University of Leeds. Most of the remaining specimens were provided by the firm of A. F. Gallun & Sons Company, in whose laboratories the work was done. The interesting photographs illustrating the drying of gelatin blocks were furnished by Dr. beige Sheppard, of the Eastman Kodak Company.
Grateful acknowledgment is made of the generous criticisms and suggestions given by Mrs. Marion Hines Loeb, of the University of Chicago, on the general histology of skin; by Dr. Jacques Loeb, of the Rockefeller Institute, on the physical chemistry of the proteins; and by Professor A. W. Thomas, Mr. Frank L. Seymour-Jones, and Miss Margaret W. Kelly, of Columbia University, on many important points throughout the book.
The author is most deeply indebted to the late Arthur H. Gallun, whose devotion to the cause of leather chemistry has made arate a large portion of the data presented in this book.
Preparation of Sections and Photomicrographs for Study—General Histology of Skin—Cow Hide—Calf Skin—Sheep Skin—Goat Skin— Hog Skin—Horse Hide—Guinea Pig Skin—Fish Skins—Other Skins.
Donnan’s Theory of Membrane Equilibria—Swelling of Protein Jellies—The Acid-Protein Equilibrium—Repression of Swelling by Salts —The Alkali-Protein Equilibrium—Two Forms of Collagen and Gelatin—Electrical Potential Difference between Protein Jelly and Aqueous Solution—Rhythmic Swelling of Protein Jellies—Structure of Gelatin Solutions and Jellies—Relation of the Osmotic Pressure and Viscosity of Gelatin Solutions to the Swelling of Gelatin Jellies—Osmotic Pressure and Membrane Potentials—Changes in Viscosity of Gelatin Solutions with Time—Theory of Salting Out and the Stability of Colloidal Dispersions—Adsorption.
Sweating—Liming—Plumping and Falling—Fresh vs. Mellow Lime Liquors—Unhairing by Means of Other Alkalies—Unhairing by Means of Acids—Unhairing by Means of Pancreatin—Combined Bating and Unhairing by Means of Pancreatin.
Falling—Regulation of Hydrogen-lon Concentration—Deliming—Bacterial Action—Enzyme Action and Elastin Removal—FEffect of Hydrogen-Ion Concentration—Effect of Time of Digestion—Effect of Concentration of Enzyme—FEffect of Concentration of Ammonium Chloride —Distribution of Elastin Fibers in the Skins of Different Animals— Effect of Elastin Removal on the Final Leather—Digestion of Collagen during Bating.
Classification—Sources of Tanning Materials—Leaching—Effect of Temperature—Effect of Hardness and Alkalinity of the Water—Effect of pH Value on the Color of Tan Liquors—Effect of pH Value on the Oxidation of Tar Liquors—Effect of pH Value on the Precipitation of Tan Liquors—Clarifying, Decolorizing and Drying.
Practical Definition of Tannin—The Gelatin-Salt Test for Tannin— The Determination of Tannin—A. L. C. A. Method—Wilson-Kern Method—Comparison of A. L. C. A. and Wilson-Kern Methods—Effect of Washing—Conversion of Nontannin into Tannin—Effect of Aging —Effect of pH Value—Modified Wilson-Kern Method—Potential Difference of Tannin Solutions—Isoelectric Points of the Tannins—Precipitation of Tan Liquors.
The Structures of Tanned Skins—Rate of Diffusion of Tan Liquor into Gelatin Jelly—Rate of Tanning as a Function of Time and Concentration of Tan Liquor—Rate of Tanning as a Function of pH Value—Stability of the Collagen-Tannin Compound at Different pH Values—Effect of Neutral Salts upon the Rate of Tanning—Degree of Plumping of Skin as a Function of Concentration of Acid and Salt in Tan Liquors—Rapid Tannages—Theory of Tanning—Procter-Wilson Theory—Oxidation Theory.
Chromium Collagenate—Hydrolysis of Chromium Salts—Diffusion of Chromium Salts into Protein Jellies—The Time Factor in Chrome Tanning—The Concentration Factor in Chrome Tanning—Effect of Neutral Salts upon Chrome Tanning—Effect of Salts of HydroxyAcids upon Chrome Tanning—Comparison of Chrome and Vegetable Tanned Leathers—Theory of Chrome Tanning.
Combination of Chrome and Vegetable Tanning—Alum Tanning—Iron Tanning—Tanning with Colloidal Silicic Acid—Miscellaneous Mineral Tannages—Tanning with Oils—Tanning with Aldehydes and Quinones —Tanning with Syntans.
Introduction.
Leather chemistry is one of the most fascinating branches of industrial chemistry and also one of the most complex, dealing, as it does, with reactions between those poorly defined groups of substances, usually colloidal, whose compositions are still matters for speculation. The raw skin is composed largely of various kinds of protein matter and is complicated by a structure which varies considerably in different animals and even in different parts of the same skin. Conversion into leather involves the removal of some of these proteins by the action of alkalies, enzymes, or bacteria, and the interaction of the remainder with tanning materials, oils, soaps, emulsions, mordants, dyestuffs, gums, resins, and other complex materials. During these reactions the structure of the skin must be carefully preserved, or improved, and highly developed technic is required to impart to the resulting leather certain necessary, but almost indefinable, properties, many of which it is an art even to appreciate fully. When one considers the vast amount of energy expended by organic chemists upon the materials involved in making leather and the uncertainty of our knowledge concerning the individual substances, the complexity of the whole problem becomes more apparent.
Leather manufacture as an art probably antedates chemistry as a science. Well preserved specimens of leather from ancient Egypt bear testimony to the high state of development of the art over three thousand years ago. Its origin presumably dates back to the time when man first began to kill animals for food. The skins, not being palatable, were very likely discarded at first, but the value of dried skins for clothing, or protective covering, could hardly remain long undiscovered. Dried skins are hard and stiff, but would become considerably softer and more pliable after being bent and worked during use, and it was probably noticed very early that this softening action is more pronounced if the skins are worked while being dried, especially in the presence of fats, such as would naturally cling to the skins of animals crudely flayed. In rainy seasons, when the skins could not
12 THE CHEMISTRY OF LEATHER MANUFACTURE
be dried rapidly, putrefaction of the epidermal cells would cause the hair to slip and reveal the advantages of unhaired skins for certain purposes. The tanning and coloring actions of leaves, barks, and woods were probably also accidental discoveries of a prehistoric age. In fact, many of the tannery operations in use today are of ancient origin. | Secrecy and lack of accurate records make it difficult to follow the evolution of the art, especially in the matter of details essential to the production of the finer qualities of leather. But developments have not all been made by rule-of-thumb methods, as has often been supposed. The great success of a certain class of tanners, for example, has been due to the development of a science of leather manufacture, as distinct from the art, based upon a belief in the constancy of natural laws and involving the organization and classification of countless facts gained by experience or handed down from previous generations. This science, because of its high degree of specialization, has proved more powerful in a practical way than chemistry, so much so that chemistry must still be regarded as of value primarily in supplementing and not replacing the science of the tanner.
Disillusionment has been common among chemists entering this industry, as the result of the unexpected intricacy of the application of chemistry to leather manufacture, of insufficient training, of false notions of superiority over artisans who had devoted their lives to the industry, or of failure to appreciate that the tanner’s own science is usually far more reliable than the chemistry of a beginner in the industry.
~In order to make substantial progress, the chemist must, asa rule, devote himself completely to a study and explanation of the mechanism of each step of a process already in successful operation and without in any way interfering with the operation of that process. Once available, sound explanations of the mechanism of existing processes are of incalculable value in suggesting practical experiments leading to the elimination of unnecessary operations and to the improvement and development of others.
That this procedure has not been more widely adopted is easily explained. Long and costly studies are required for which there is no immediate return, and whether there will ever be a return commensurate with the cost of the studies must depend upon the skill of the chemist, which it is difficult for the tanner to judge. Moreover, the qualifications required of the chemist are extremely severe. He must have a broad, theoretical training, marked ability to advance the pure science, great skill in adapting delicate apparatus to crude, tannery conditions, and power to appreciate the viewpoint of a successful tanner. Previous contact with the industry, on the other hand, is not essential.
That close codperation between the university and the industry would be highly profitable to both cannot be denied, but there is little chance of such cooperation being brought about until each acquires. a better understanding of the needs and potentialities of the other. The stumbling block has been either the failure to appreciate the value
initiative.
The university can derive at least three important lines of advantage from cooperation with the industry, the most obvious of which is much needed financial support. But the laws af-the; conservation of mass and energy hold in industry, as in everything else. The university cannot continue to receive from the industry without returning a like amount, although this may be of a different kind. The university has vast resources of potential wealth, but it suffers from having too little in liquid form. But industry constitutes a means of converting one form of wealth into another. The university can be assured a continuous financial support from the industry, but only by supplying the industry with the means of producing this wealth.
Another advantage to be gained by the university is the viewpoint of the industry, which is necessary for the university to prepare its potential wealth so that it may be assimilated by the industry. This viewpoint will also help the university to train its students to make a greater success in industry. The third advantage lies in the fact that the industry offers a field of employment for the students of the university. The industry is always in need of men _ properly trained from its own viewpoint. But, too often, the training which men receive at the university does not equip them with a power of service to the industry that is in demand at all times. Through closer cooperation a system of training could be devised that would guarantee the opportunities of industry to men with initiative and ambition. |
The source of wealth that codperation offers to the industry consists of fundamental data and of men trained to apply these data to practical production. The possibilities for increasing efficiency in the industry are almost unlimited and so are the profits to be derived by both the university and the industry from intelligent cooperation.
Chemists within the industry have always been handicapped by lack of fundamental information. Many of the physical properties that determine the value of leather are determined by its microscopic structure, but very few tanneries have found themselves in a position to develop the means for studying the histology and chemical constituents of skin and the structure of leathers made under different conditions. Such studies are expensive and time consuming and their development in each individual tannery would be very extravagant. The _ industry could well afford to finance a laboratory to be devoted solely to such studies, which would probably cover a period of many years. That a good start has been made will be evident from a perusal of the next chapter.
The physical chemistry of the proteins is a subject of fundamental importance to leather chemistry, but, since it is also of fundamental importance to many other branches of chemistry, it should be possible for some good university laboratory to establish a great scheme for co-operative work in this field, drawing financial support from
many different fields. A. university research laboratory is also an ideal place in which to study both the physical and organic chemistry of the proteins and the natural tannins. Physical chemistry offers much the better prospects for immediate application to manufacturing practice, but both should be developed simultaneously.
ness of purpose, established a research in the fundamentals of leather chemistry, under the direction of Professor A. W. Thomas, of Columbia University, with the proviso that all results be published freely for the henefit of the industry as a whole. The results obtained during the past few years compare favorably with all previous work done on the mechanism of chrome and vegetable tanning. It will be evident from the description of this work, in the later chapters, that it must ultimately prove of great practical value and it is difficult to see how it can fail to gain the support of the entire industry in due time. It is worthy of special mention here as a demonstration of a kind of cooperation that should prove very profitable to both the university and the industry.
It is hoped that the following pages will give chemists in many fields a better understanding of the problems of the leather industry and of the opportunities for cooperative research, and also give the industry itself a clearer appreciation of the possibilities for further extending the application of pure chemistry to leather manufacture.
Histology of Skin.
Since animal skin is the basis of leather, the importance of its histology to the science of leather manufacture israpparent.> =Nevertheless scientific advancement, especially in regard to the preparation of skin for tanning, has been retarded by an insufficient knowledge of the histology of the skins of animals used in making leather. This has been due less, perhaps, to lack of appreciation of the value of histology than to the high degree of refinement of equipment and technic required for its study.
Much of the complexity of the structure of the skin is due to the manifold purposes it serves. As a means of protection for the underlying organs, it is so constructed as to act as a buffer against shocks or blows, while not interfering with the operation of any organs. It is an organ of sense, equipped with nerves sensitive to touch, pain, heat and cold, and, as an organ of secretion and excretion, it is supplied - with glands, ducts, muscles, and blood vessels. It serves also as a regulator of the body temperature, which it controls by regulating the evaporation of water from its surface and the secretion of oil to cover the surface in order to prevent too great a loss of heat.
The degree to which each constituent part of the skin is developed depends upon the extent to which it is needed by the body and also upon the amount of available nourishment. The structure of a single skin varies considerably in different regions of the body. Nerve papilla, for example, are very numerous in regions where the sense of touch is most needed, as in the finger tips, and widely scattered in other regions. The skin structure is developed to meet sudden changes of temperature to the greatest extent in the regions of. the body most exposed to such changes and to resist friction and blows where these are most frequent. In fact, the skin tends to develop a structure at each point designed to be of greatest service to the body at that point. This results in a large number of types of skin structure that must be studied, depending upon the species of animal, the general nature of its feeding, the climatic conditions under which it lived, and the region of the body from which the specimen is taken.
The number of possible types appears formidable, but tanners have learned from experience how to classify them in a general way according to the properties of the leather they yield. It seems reasonable to. believe that histologists may be able to develop a similar classification, based upon histology, that will prove extremely valuable in supplementing the tanners’ information.
Because of the large number of highly trained investigators in the medical sciences, considerable progress has been made in the histology of human skin. This work is invaluable as a guide to the student of the histology of the skins of lower animals because most skins possess a common basic structure. But the several types of skin exhibit such marked differences in details of structure of vital importance in leather manufacture that a knowledge of the histology of a few specimens of human skin alone might actually be misleading. In order to apply histology intelligently to leather manufacture, separate studies must be made of the structure of each type encountered.
Although much yet remains to be learned of the histology of skins used for leather manufacture, substantial progress has been made, the most notable work being that of Alfred Seymour-Jones.1 Systematic studies have also been under way in the author’s laboratories, for several years, dealing with the structure of the skins of different animals and the changes which they undergo during the conversion of the skin into leather. In this book much of this work is presented for the first time.
Preparation of Sections and Photomicrographs for Study.
Since much of the information given in this chapter was obtained by direct observation of sections prepared in the author’s laboratories, a description of the methods employed will probably assist in making the presentation clearer, particularly so in view of the fact that work of this kind appears not to have been general in tannery laboratories. The description, however, will be limited to the methods used in the production only of the photomicrographs appearing in this book. The subjects of microscopy, microtomy, and photomicrography are too vast in scope for adequate treatment here and the reader desiring to pursue these subjects further is referred to the several excellent works available, such as those of Gage? and Lee.’
Sampling.—In studying the entire skin of an animal, strips of about 0.5 x2 inches were cut from different parts of the skin so as ta show, not only the general structure, but also its variation throughout the skin. Care was taken, in cutting the strips, so that the later sectioning could be done in definite planes, as, for example, that including a hair follicle and erector pili muscle. It was found important that the plane selected be uniform for any given series of sections showing changes taking place during the passage of a skin through the tannery processes.
Fixing.—After a tissue dies, the structure undergoes a gradual change unless it is immediately fixed. According to Lee, the word fixing implies two things: “first, the rapid killing of the element, so that it may not have time to change the form it had during life, but is fixed in death in the attitude it normally had during life; and
second, the hardening of it to such a degree as may enable it to resist without further change of form the action of the reagents with which it may subsequently be treated. Without good fixation it ts impossible to get good stains or good sections, or preparations good in any way.” |
The photomicrographs shown in this book are from sections fixed either in Erlicki’s fluid or in alcohol. Numerous other fixing agents were tried, but they did not answer so well for the specific purposes in view. E[rlicki’s fluid is made simply by dissolving 25 grams of
potassium dichromate and 10 grams of copper sulfate in a liter of water. The strips of fresh skin were placed directly into this solution without previous washing. ‘They were transferred to fresh solu- tions daily for the first 3 days and then kept in the last bath until the solution had thoroughly penetrated them. The period of contact was usually from 5 to 7 days, after which they were washed in running tap water for about 20 hours and then dehydrated with alcohol.
The skins of the sheep, cow, calf, and guinea pig, whose sections are shown in this book, were fixed immediately after the animals were killed. Their sections may, therefore, be regarded as showing the normal structure of the living skin. The other sections exhibit structures of skins as the tanner usually receives them.
A duplicate series of strips of fresh skin was fixed in dilute alcohol, in each case, for comparison with those fixed in FErlicki’s fluid. Sections from the Erlicki fixer generally showed various details more sharply than those from alcohol alone. All specimens of skin from the unhairing and bating processes were fixed in alcohol in order to avoid possible complications due to the reactions of the Erlicki fixer with the tannery liquors. Samples of air-dry leather were not fixed, but were imbedded in paraffine either directly or after soaking in santalwood oil and then in molten paraffine.
The mixture of alcohol and xylene consisted of equal volumes of the two. The carbol-xylene is known as a clearing agent and has for its object the removal of alcohol from the specimen; it is prepared by mixing 25 cubic centimeters of melted phenol with 75 cubic centimeters of xylene. Very thick specimens had to be left in the molten paraffine for a much longer time, the object of this bath being to replace the
xylene by paraffine. The strips from the paraffine bath were suspended in aluminum beakers, having a capacity of 100 cubic centimeters, and covered with molten paraffine. The beakers were then plunged into cold water and kept there until the paraffine had completely solidified. The beakers were then heated just sufficiently to loosen the paraffine blocks, which were pulled out and cut into the proper size and shape for placing in the microtome.
Sectioning.—Really good work in preparing sections is possible only when the microtome knife is free from nicks and extremely sharp, the sharper the better. The thickness to which it is desirable to cut . the sections depends upon the particular part of the skin to be studied. For a general picture of the whole skin, a thickness of 20 microns is satisfactory.
In the sections of skin taken from the unhairing processes, it will be noticed that there would be nothing to hold the loose epidermis and hair in place, if these were not securely fastened to the slide in some way. In order to prevent the loss of important material from the sections, the entire paraffine ribbons from the microtome were fastened to the slides by means of Mayer’s albumen fixative. This is made by mixing equal parts of glycerin and well-beaten white of egg, adding 2 per cent of sodium salicylate, and filtering. A tiny drop of this fixative was spread evenly over the middle of a slide with the finger and was then covered with water. A ribbon, containing a section of skin, was then floated onto the water, which was heated over an alcohol lamp carefully so as not to melt the paraffine. This causes the ribbon to spread out flat and it was then worked into place and smoothed out with a camel’s-hair brush. Slides prepared in this way were left to dry for at least one day, the sections meanwhile becoming securely fastened. They were then freed from paraffine by flooding the slides with xylene, after which they were. washed with absolute alcohol in preparation for staining. |
Staining.—Six stains were used in preparing the sections shown in this book, with the exception of those of the human heel and scalp. These two sections were prepared in Professor Bast’s laboratory and were stained with Delafield’s hematoxylin and eosin. Where an aqueous stain was to be employed, the section was soaked, for several minutes, successively in the following strengths of alcohol: 95 per cent, 75 per cent, 50 per cent, 25 per cent, and then in water. After the staining, it was worked up through the series of solutions of alcohol in the reverse order, finally being rinsed with absolute alcohol. The six stains used were prepared as follows:
(1) Van Heurck’s logwood: 6 grams of powdered logwood extract and 18 grams of alum were ground together in a mortar and 300 cubic centimeters of water added slowly. The mixture was then filtered and 20 cubic centimeters of alcohol were added to the filtrate. The solution was kept exposed to air for several weeks, water being added to replace that lost by evaporation. The sections were kept in this stain for 3 minutes, rinsed in tap water until they turned blue, and then passed through the series of alcoholic solutions of increasing —
strength. Sections were transferred from the 95-per cent alcohol to the picro-indigo-carmine solution, where this was used for counterstaining. But where the counterstaining was done with bismarck brown, the sections were transferred from the 95-per cent alcohol to a 0.1-per cent solution of HCl in absolute alcohol, where they were kept until they turned pink and no more color was seen to wash away, after which they were rinsed with fresh alcohol and put into the bismarck brown stain.
(2) Friedlander’s logwood: 2 grams of powdered logwood extract dissolved in 100 cubic centimeters of alcohol were mixed with 2 grams of alum dissolved in 100 cubic centimeters of water and 100 cubic centimeters of glycerin. This was used like Van Heurck’s stain.
(3) Picro-indigo-carmine: To 100 cubic centimeters of 9o-per cent alcohol was added 1.0 cubic centimeter of absolute alcohol saturated with picric acid. This solution was then saturated with indigo carmine and allowed to stand with an excess of indigo carmine, with occasional shaking, for several weeks. The decanted solution was used. Sections were kept in this stain from 3 to 4 hours.
(4) Picro-red: 5 cubic centimeters of absoltite alcohol saturated with picric acid were added to 55 cubic centimeters of go-per cent alcohol saturated with the dye Leather Red-X. This solution was diluted with alcohol to 10 times its volume before using. Sections remained in this stain for 2 minutes.
(5) Weigert’s resorcin-fuchsin: 2 grams of basic fuchsin and 4 grams of resorcin in 200 cubic centimeters of water were boiled for IO minutes, 25 cubic centimeters of a 30-per cent solution of ferric chloride were then added and the boiling was continued for 5 minutes. Then a saturated solution of ferric chloride was added until all of the color was precipitated. The mixture was allowed to stand over night to cool and settle and the supernatant liquor was decanted off and discarded. The residue was dissolved in 200 cubic centimeters of boiling 95-per cent alcohol and the hot solution was filtered into a bottle. After it had cooled, 5 cubic centimeters of concentrated HCl were added. For staining, this solution was diluted with an equal volume of alcohol and sections were left in it from 60 to 90 minutes, after which they were rinsed with alcohol.
(6) Daub’s bismarck brown: To 95 cubic centimeters of absolute alcohol were added 5 cubic centimeters of saturated lime water and then more bismarck brown than would dissolve and the whole was shaken and allowed to settle, the solution being decanted off after standing for several days. Fifteen cubic centimeters of alcohol were added to the solution to replace any lost by evaporation, which would otherwise cause a precipitation of some of the dye. Sections were kept in this stain for 1 day.
Mounting.—Since the sections of untanned skin were fastened permanently to the slides before staining, the mounting of these was a very simple operation. After the sections were stained, they were rinsed successively with absolute alcohol, alcohol-xylene, carbol-xylene, and xylene. Each section was then covered with a drop of Canada
and ready for study or photographing.
Sections of leather, from the microtome, were uncurled on a piece of smooth paper and fastened by pressing on the paraffine surrounding the sections. They were then removed from the paper in a flattened condition by means of tweezers, dipped into a I-per cent solution of parlodion in equal volumes of alcohol and ether, and then transferred to slides previously coated with a thin film of santalwood oil. They were carefully smoothed out, covered with santalwood oil, and allowed to stand exposed to air until the alcohol and ether had evaporated, usually about 30 minutes. They were then washed with xylene and covered with balsam and cover glasses. As a rule the staining’ of leather sections for study is unnecessary, but a stain often assists in getting sharper photographs. Where a stain was employed on leather, the fact is noted under the photomicrograph.
Photographing.—All photographs were taken with a standard type of photomicrographic apparatus. Wratten and Wainright “M” plates — were used and developed according to the directions which accompany them. The source of light transmitted through the sections was a 6-volt mazda lamp having a concentrated filament. The light was filtered through appropriate color screens, consisting of the standard Wratten filters. The stains on the sections, together with the color screens, generally furnished all the detail or contrast necessary, but where this was not entirely satisfactory, the plates, after developing, were treated with standard intensifying or reducing agents as needed.
Certain precautions were necessary in photographing grain surfaces for comparison. The hair follicles run obliquely to the surface, in consequence of which the lights and shadows depend upon the angle at which the light strikes the openings of the follicles. This was made uniform for all skins with nearly straight follicles by using for reference the plane including the line of the follicle and intersecting the plane of the grain at right angles. A beam from a powerful arc lying in the plane perpendicular to these two planes was made to strike the grain surface at an angle of 45 degrees. ;
General.—Halftones were used to reproduce all photomicrographs excepting those in Figs. 20 to 27 inclusive, which were printed from line etchings. Because of the low magnification and consequent fineness of the fibrous tissues, a good reproduction could not be obtained by means of halftones; even a very fine screen produced an appreciable blurring effect. Line etchings, made without a screen, gave a much better result, the resulting increase in sharpness of the fine lines more than compensating for the loss in shading.
All vertical sections are shown with the outer surface of the skin upward. Under each photomicrograph is given the location or region of the body from which the specimen was taken, where this was known, the thickness at which the section was cut in the microtome, the stains applied to the section, the eyepiece, objective, and filter used in photographing, and the final magnification of the section as it appears in the book.
It is not: uncommon to find in the literature descriptions of skin structure that apparently clash. Occasionally an author will present what purports to be a general description, but which is actually based upon the examination of a single type of skin structure. Figs. 1, 2, and 3 all represent vertical sections of human skin, but the first was taken from the scalp, the second from the lower part of the back, and the third from the heel. A detailed description of one would give a very misleading picture of either of the others. In the section from the scalp, fat cells make up the greater portion of the whole, while in that from the back there are relatively very few fat ‘cells, but a great abundance of fibers of connective tissue. In the section from the heel, fat cells and connective tissues are both very prominent, but no hairs are seen. Practically, these sections represent very different types, yet all three conform to a common basic structure. A structure common to all skin may be greatly exaggerated in one type and scarcely detectable in another.
All four general classes of tissues, epithelial, connective, muscular, and nervous, are present in the skin, as well as those of the blood. These tissues either consist of cells or are the product of cells. The epithelial tissues consist of layers of cells, which cover all the free surfaces of the animal body. The connective tissues are distinguished from the other fundamental tissues of the body by the fact that their cells lie imbedded in extracellular material which appears to be the result of their activity. The various types of connective tissues are distinguished among themselves by the kind of extracellular tissue which they produce, such as bone, cartilage, etc. The muscular tissues have a well developed power of contracting, apparently without change of volume, the decrease in length being compensated by an increase ‘n diameter. The cells of the striated or involuntary muscles are long in relation to their width and are marked with transverse bands, while those of the nonstriated or involuntary muscles are spindle shaped, without transverse striations. The nervous tissue found in the skin is a protoplasmic prolongation of cells lying in the central nervous system, or in the ganglia closely associated with that system.
The skin is divided sharply into two layers, distinct both in structure and origin: a relatively very thin outer layer of epithelial tissue, the epidermis, and a much thicker layer of connective and other tissues, the derma. Raw skin, as an article of commerce, has also a third layer, the superficial fascia, known to the tanner as the adipose tissue or, more commonly, the flesh. In keeping with the nomenclature of the leather trade, the word flesh will be used only in this connection, although in anatomy flesh really means muscle tissue. In life, the adipose tissue, or flesh, connects the skin proper very loosely to the underlying parts of the body. The derma lies between the epidermis and adipose tissue.
epidermal system must be removed intelligently and with extreme care, leaving the derma to be converted into leather. The epidermal system, adipose tissue, and derma will be described in turn.
The epidermis is made up of a cellular strata originating from the ectoderm, the outer layer of the young embryo, and independently of the derma, which is derived from the mesoderm, or middle layer. These two layers grow independently throughout life and differ materially in both chemical and physical properties. In Fig. 2 the epidermis can be seen as a dark band forming the upper boundary of the skin and constituting only about 1 per cent of the total thickness. So far as its growth is concerned, the epidermis may be looked upon as a parasite, although it is a most important part of the body. It has no blood vessels of its own, but rests upon the upper surface of the derma and draws its nourishment from blood and lymph supplied by the blood vessels of the derma. It grows only through the reproduction of its own cells.
The portion of epidermis in contact with the derma is a layer of living epithelial cells, rather elongated in shape. It may be mentioned that a cell consists of a nucleus suspended in protoplasm enclosed between very thin walls acting as a semi-permeable membrane. Nourishment from the lymph and blood streams diffuses through the cell walls, and after a certain period of growth the cell divides mitotically, forming two cells. ‘This change appears to be initiated by the nucleus. In the deepest layer of the epidermis, each cell increases in height and then subdivides, forming two cells, one above the other. _ This process is repeated indefinitely. As the older cells are pushed outward, they become flattened by dehydration and other changes. During this process, the protoplasm dries up and the cells lose their power of reproduction. In the outermost layer, the cells are very dry and scaly and are gradually worn away. ‘This scaling is often very noticeable on the scalp in the form of dandruff, which, in itself, is not the result of a disease, but rather is evidence that the epidermal cells are functioning and reproducing vigorously.
Where the epidermis is very thick, as on the heel, the gradual transition which the cells undergo in their outward course gives the epidermis the appearance of having several distinct layers. The portion of the epidermis shown in the upper left hand corner of Fig. 3 is shown at a very much higher magnification in Fig. 4. Now the several strata can be seen very plainly.
The layer marked E is the uppermost part of the derma and numerous protuberances of its surface, called papillae, can be seen extending upward into the epidermis, giving the boundary between epidermis and derma a serrated appearance. D is the Malpighian layer of the epidermis, or stratum mucosum. It is built up of several rows of living epithelial cells, whose nuclei appear in the picture as dark spots or rods. ‘Tiny fibers, often called prickles, pass from cell to cell, holding them together and securing them to the derma. Extending between these prickles, which look as if they were walls in section, are protoplasmic processes and it is supposed that food passes upward
between the cells and waste from the upper layers downward. From this food the cells derive the nourishment necessary for reproduction. This layer contains no blood vessels, but very fine nerve fibers pass from the derma into this layer, forming a network between the cells and terminating in bulbous swellings or undergoing a gradual breaking up into nerve granules.
As the new cells are formed, the older ones are pushed outward where nourishment is no longer available and the protoplasm of the cells gradually dries up. Upon staining, the cells then appear as though they contained coarse granules and form the layer shown at C, which, from its appearance, has been called the stratum granulosum. The cells also contain a pigment, which is at least partly responsible for the color of the skin. This pigment, known as melanin, is thought to be a derivative of hematin containing iron and sulfur. It is very concentrated in the skin of the negro and almost entirely absent from the skin of a blonde. Apparently the pigment is formed as a protection against strong sunlight, both for the skin and the underlying tissues. The pigmented layer may thus be looked upon as a color filter. When the pigment-containing cells are collected in spots, they appear as freckles. The pigment in the negro skin is found in the deepest cells of the stratum mucosum, in the connective tissue cells of the upper part of the derma, and in the wandering cells of the lymph, found in the lymph spaces or between the cells of the epidermis or connective tissues. The pigment granules are found only in cells.
As the cells are pushed still further outward, the cell granules break down, yielding a material, called eleidin, which resists staining and gives the epidermis in this region a transparent appearance, from which it has derived the name stratum lucidum. This layer is shown at B.
The cells continue to undergo changes during their outward course, becoming drier and flatter, and finally form the very thick layer shown at A, the stratum corneum, in which the cells tend to break away from each other and to scale off. This layer is being worn away continually and is replaced by the newer cells from below. The corneous layer is a very poor conductor of heat and the waxy material usually present on its surface makes it water repellent. In the photomicrograph a duct can be seen taking a spiral course up through the corneous layer. This is the outlet of a sudoriferous or sweat gland seated in the derma. Its opening at the surface of the corneous layer is called a pore.
All of the strata noted above can be detected only where the epidermis is very thick. Elsewhere only the stratum mucosum and stratum corneum are visible. In no case have we yet observed a section of skin used for making leather where more than these two layers could be recognized in the epidermis.
The independent growth of the epidermis and derma involves a number of important appendages of the skin. In the epidermal system, the reproduction of epithelial cells produces, not only the epidermis, but also the hair and the sebaceous and sudoriferous glands. These cellular structures are composed of proteins of the class known
as keratins as distinct from the collagens and elastins of the derma. Where a portion of the epidermis is lost, through accident, it can be regenerated only by the surrounding epithelial cells spreading over the bare spot, by reproduction. The necessity for removing the epidermal system completely before tanning and without any injury to the derma makes the difference in chemical composition between the two systems a matter of great importance to the tanner.
In the class with hair belong also nails, claws, hoofs, scales, and feathers, which are all special growths of the epidermis. To the naked eye, the hair appears to pierce the skin, but actually it does not do so. An examination of Fig. 2 will show that the epidermis dips down into the body of the derma, forming a pocket, or follicle, in which the hair grows. The follicle is complex in structure because it is made up of the epidermal layers on the hair side and of the layers of the derma on the other. At its bottom, the follicle is penetrated by a projection coming from the derma and known as the hair papilla, which is supplied with both nerves and blood vessels.
A good example of a hair papilla is shown in Fig. 5 in the hair bulb from the skin of a hog. The bottom end of the bulb appears like a pair of pincers with the jaws slightly open and facing downward. A similar structure may be seen in the hair bulbs of the scalp shown in Fig. 1. Passing through the opening in the jaws into the large open space above and resembling a candle flame in shape is the papilla, which contains tiny nerves and blood vessels which supply nourishment. Lining the lymph space surrounding the papilla are numerous epithelial cells, which derive from the blood and lymph the nourishment necessary for reproduction. As new cells are formed, the older ones are pushed outward through the follicle, forming the hair. The rate of growth of the hair is determined by the rate at which the cells surrounding the papilla reproduce.
The newly formed cells of the hair, like those of the Malpighian layer of the epidermis, are very soft. As they are pushed upward, they become elongated in shape and harder. In forming the hair, they assume the shape of the follicle; if this happens to be curved, the hair will be curly. In the negro, the follicles often have a curvature of nearly go degrees, which accounts for the tightness of the curls.
The portion of the hair showing above the surface of the skin is called the shaft and the lower portion the root, which enlarges ‘nto a bulb at its lower extremity, where it is penetrated by the hair papilla. The shaft is made up of a central medulla, or pith, of rounded cells, containing eleidin granules, surrounded by a much thicker portion composed of long fibrillated cells, containing pigment, and enclosed by an outer layer of cells which become hardened in the form of overlapping scales. These scales, which give fur and wool their felting properties, open outward so as to resist the pulling out of the hair. Unless the lighting is properly adjusted and the magnification sufficiently great, the scales are not easily discernible. In Fig. 6 may be seen the scales of a tiny piece of wool. The scales of one side and the shadows of those on the other both show because the wool
can be seen on most hair, but it is not always so pronounced. .
When a hair is shed, after reaching the limit of its existence, the epithelial cells left surrounding the hair papilla keep on multiplying and soon another hair is formed to replace the one shed. Baldness results from the failure of the blood vessels of the papilla to furnish the required nourishment or from the destruction of the epithelial cells in some other way. Any serious attempt to grow hair on a bald head must be accompanied by some means of introducing living epithelial cells into the hair follicles, of which there are something like a thousand to the square inch. In other words, we cannot grow a crop without seeds or seedlings.
In old age, pigment is no longer available for the hair cells and the new hairs, containing no pigment, appear gray in color. Hair containing pigment, however, may look white by reflected light, due to the presence of tiny air bubbles among the cells.
Each hair follicle is supplied with sebaceous glands with ducts emptying into the upper portion of the follicle. A group of these glands can be seen in Fig. 2. They are lined with epithelial cells which secrete from the blood the materials required for the synthesis of the oils which they produce. When they become charged with oil, the protoplasm disappears and the cell breaks down, discharging the oil into the duct. New cells are continually being formed to replace the old ones. The oil is forced into the follicle, where it coats and lubricates the hair, and finally to the surface of the skin, which it softens and protects against the cold. In contact with air, this: oil thickens to the consistency of ear wax, to which it is related. When the ducts become clogged with dirt, the pressure behind them causes them to become distended, giving rise to blackheads. Sebaceous glands are sometimes found also in parts of the skin free from hair.
Attached to each hair follicle, just below the sebaceous glands, and extending obliquely upward through the derma, almost to the surface, is a bundle of nonstriated muscle tissue, known as the erector pili muscle. In Fig. 2 one of these muscles forms a V with the hair follicle, and the sebaceous glands may be seen within the angle so formed. The nerves supplying these muscles are known as the pilomotor nerves. These muscles contract under the influence of emotions, such as fear, surprise, anger, or other disagreeable states, or in response to cold or grazing tactile stimuli. Among the commoner visible effects are the roughening of the skin called goose-flesh and the effect of the hair standing on end, very pronounced in a frightened cat.
_ The real purpose of the erector pili muscles 1s apparently to protect the body against sudden changes of temperature by their control over the operation of the glands; they seem to act as effectively as a thermocouple in a good thermostat. Their contraction puts a pressure on the glands which causes the cells to give up their oil to the hair follicle and, in the process, the cells are destroyed. The oil is then forced up through the follicle to the surface of the skin, where
evaporation of water from the surface of the skin.
The sudoriferous or sweat glands are coiled sacs with spiral ducts leading to the surface of the skin. In Fig. 3 several of these ducts can be seen winding up through the epidermis and terminating at the surface as pores. Often the ducts seem to lead into the hair follicles above the openings of the ducts of the sebaceous glands. The sacs of the sweat glands are lined with epithelial cells, which are continuous with the cells of the Malpighian layer of the epidermis, and which secrete water, salts, urea, and other wastes from the blood and pass them out through the ducts. Where no sebaceous glands are present, the sudoriferous glands also provide an oily fluid to keep the surface of the skin soft. These glands serve the dual purpose of disposing of waste products and of permitting control of the body temperature through the regulation of the rate of evaporation of water. ;
This entire epidermal system, including the epidermis, hair, and sebaceous and sudoriferous glands, must be removed from the skin in such manner that the derma suffers no injury that can be detected in the finished leather.
The skin is connected to the underlying parts of the body very loosely by means of fibers of connective tissue, usually called adipose tissue because it is so frequently the seat of fat deposits, most numerous in the vicinity of the abdomen, which serve to protect the body against cold. The looseness of connection allows the skin very free movement and, incidentally, makes flaying a much simpler matter than it would otherwise be. ‘The adipose tissue, while not a part of the skin proper, is of importance to the tanner because much of it remains adhering to the skins received at the tannery and must be removed prior to tanning. If left on the skins, it greatly impedes the progress of tanning.
In Fig. 7 is shown a vertical section of adipose tissue from the butt of a calf skin along with the lower portion of the derma. The top quarter of the picture shows a portion of derma bound on its under side by strands of elastin fibers, appearing as compact masses of black threads; actually they are of a pale yellow color. The fat cells of the adipose tissue are arranged in layers and are held together by fibers of connective tissue. The light colored tissues are the white fibers, composed of collagen, and the dark ones are the yellow fibers of elastin. Large arteries, nerves, and veins which supply the derma traverse the adipose tissue in many places and can often be seen heavily protected with connective tissue. ‘This region is sometimes supplied also with striated muscle fibers to permit the voluntary twitching of the skin.
The removal of the adipose tissue of the skin, preparatory to tanning, is an operation known as fleshing. This is done efficiently when all of the tissues underlying the derma are cut away, leaving the derma itself entirely intact.
and the chief leather-forming constituent of the derma is collagen, the substance of the white fibers of connective tissue. Sound leather can be produced only from skins in which these fibers are well developed and abundant. The three contrasting structures in Figs. 1, 2, and 3 are typical of the extremes found in the skins of the lower animals. The tendency toward one extreme or the other depends largely upon the habits and feeding of _the animal as well as upon its species. In considering the general structure of skin, one should look upon the major portion of the derma as consisting of both fat cells and connective tissues, either of which may be very abundant or relatively scarce.
Unlike the epithelial tissues, the major portion of the connective tissues is not made up of cells, but results from the activity of migratory cells very much smaller in size than the extracellular material. The relation of these cells to the collagen fibers of calf skin can be seen in Fig. 8. The cells stain more deeply than the fibers and appear in the picture as black specks having a diameter of about 1 millimeter, which means that the actual cells have a diameter of about 1/170th of this. In the sections we have examined, the abundance of these cells diminishes with increasing age of the animal.
By examining the cross sections of fibers running pefpendicular to the plane of the page, the arrangement of the fibers, or fibrils, in bundles can be seen very plainly. Seymour-Jones regards the fibers as enclosed in very thin sheaths of what he terms “fiber sarcolemma.” ‘While we have not been able, as yet, to detect such a sheath microscopically, the investigations of Wilson and Gallun, described in Chapter 8, seem to indicate that the surfaces of the collagen fibers are very much more resistant to tryptic digestion than the material just under the surface.
Of the two kinds of fibers composing the connective tissues, the collagen fibers are very much thicker and more abundant than the elastin fibers. ‘There is usually a dense layer of elastin fibers at the lower surface of the derma, where it is attached to the adipose tissue, as shown in Fig. 7, and another in the region of the erector pili muscles. But the greater portion of the derma seems to contain relatively few elastin fibers and these are generally to be found surrounding the blood vessels and nerves traversing the derma.
The main trunk lines of blood vessels and nerves supplying the derma run parallel to the surface just above the lower elastin layer. From these trunk lines branches shoot upward and are distributed to all parts of the derma. A network of lymph ducts also is distributed throughout the skin.
Cross sections of the arteries and veins show three distinct layers: an outer layer of collagen and elastin fibers, a middle layer of nonstriated muscle tissue and elastin fibers, and an inner membrane of
flattened cells. All three layers are pronounced in the arteries, but in the veins the outer layer is very much thicker than the inner layers, which are much less developed and collapse when the vein is empty. The veins are also equipped with semilunar valves in order to prevent backflows of blood.
A cross section of an artery can be seen at the top (ot gHig.n7 It is the large circular body just to the left of the midline. To the right of the artery is a vein, which has collapsed. The circular mass just under the artery is a cross section of a bundle of nerves. Three more sections of nerve bundles are prominent, elongated in shape, two just below the vein and one to the extreme left of the artery.
In those parts of the body where the sense of touch is well developed, as in the fingers, there are numerous protuberances of the surface of the derma into the epidermis, called papille. These are very pronounced in the section of skin from the human heel shown in Fig. 3. They are arranged in definite patterns which do not change throughout life. The design of the thumb print is produced by the papillae. They seem to be absent entirely from some parts of the body, particularly where the sense of touch is not well developed and where the epidermis is very thin. They are of two kinds, one containing blood vessels furnishing-lymph to the active epithelial cells in their vicinity and the other containing the nerves sensitive to touch, pain, heat and cold. The epidermis above the papillz is thinner than at other points, the papillze serving the purpose of bringing the nerve ends nearer to those surfaces where they are most needed.
The portion of the derma immediately in contact with the epidermis has been called the “grain membrane” by Seymour-Jones because it forms the grain surface of the finished leather. Although its boundary on the side in contact with the epidermis is very sharp, on the other side it blends into the rest of the derma with no sharp change of properties. The fibers of connective tissue grow finer as they near the grain surface, in which the fibers are extremely fine and generally run parallel to the surface. They can be seen very plainly in the horizontal section of tanned calf skin shown in Fig. 150, of Chapter 16. Whether or not the fibers of the grain surface are continuous with those of the connective tissues of the derma, they seem to possess somewhat different properties. When unhaired skin is kept in boiling
somewhat changed, long after the larger collagen fibers below have passed into solution as gelatin. The outer surface is then very sharp, but the inner side, facing the remnants of the collagen fibers, appears jellylike and heterogeneous, indicating a gradual change in properties of the fibers as they pass from the derma into the grain surface. ;
It is of great importance that no damage be done to the grain surface in removing the epidermis, because it determines the appearance of the finished leather. It is therefore fortunate for the tanner that the fibers in this surface are more resistant to the action of alkalies than the epidermis above it and more resistant to the action of tryptic enzymes than the elastin fibers below it. The grain surface
however, resulting in what is known to the tanner as pitted grain.
The design of the grain surface, as seen on the skin after unhairing and tanning, is distinct for each species of animal, while the fineness of the pattern is an indication of the age of the animal. It is due to the arrangement of the hair follicles and pores, and of the papillz where these are present. The grain surfaces of the tanned skins of a number of different animals are shown in Figs. 9 and 10. They are all magnified to exactly the same extent and are directly comparable. It will be noted that the cow and calf have the same pattern, but that it is much coarser in the older animal. These designs can be used to identify different species of animal.
Cow Hide.
In selecting skin for the production of heavy, sound and durable leather, the tanner usually chooses the hide of the steer or cow. In Fig. 11 is shown a vertical section of cow hide taken from the thickest part of the butt. The specimen was fixed in Erlicki’s fluid immediately after the death of the animal. This is the type of skin suitable for manufacture into sole leather or heavy belting or harness leather. Over 80 per cent of the total thickness of. the hide is made up of heavy, interlacing bundles of collagen fibers, the chief leather-forming constituent of skin, and very few of the fat cells that tend to make the leather spongy are to be found among these fibers.
The epidermis appears as a thin, dark line forming the upper boundary of the section and occupying barely one-half of one per cent of the total thickness, the rest being the derma, the adipose tissue having been removed from this portion of the hide in flaying. The epidermis can be seen to dip down into the derma in many places, forming the follicles in which the hairs grow.
The presence of the muscles, glands and follicles in the top fifth of the derma give this region the appearance of a layer quite distinct from the lower part of the derma. Indeed, it is advantageous, in leather manufacture, to look upon the derma as divided into two distinct layers. The dividing line might conveniently be taken as that formed by the deepest points of the sudoriferous, or sweat, glands. The lower, fibrous region of the skin is often referred to as the reticular layer because of the network appearance of the collagen fibers. This name might well be accepted for most skins suitable for leather manufacture, although it might seem somewhat strained for skins in which the derma is made up largely of fat cells. The chief func-— tion of the upper layer seems to be that of a thermostat for the body and the writer, therefore, proposes the name thermostat layer as indicating its structure as well as its chief function.
reticular layer the remaining four-fifths of the section. The advantage of dealing with these layers separately is made clear by the fact that the structure of the reticular layer determines the physical properties of the leather such as tensile strength, solidity, resilience, etc., while the thermostat layer determines more particularly the appearance of the leather. In making the finer grades of leather, a great deal of attention must be paid to the thermostat layer.
The section in Fig. 11 is magnified only 19 diameters. In order to show the structure of the thermostat layer in greater detail, the upper left hand corner of this section was magnified to 85 diameters. At this greater magnification, it is shown in Fig. 12. The Malpighian and corneous layers of the epidermis can now be clearly differentiated, the latter becoming extremely thin where it lines the hair follicle. The stratum granulosum and stratum lucidum do not appear to be present in the epidermis. Attached to the base of the hair follicle and weaving its way upward to the right is the erector pili muscle. Just above this muscle and emptying into the hair follicle is a group of sebaceous glands. The empty space near the lower left hand corner is that formerly occupied by a sweat gland whose duct has wandered out of the plane of the section, reappearing as a pore to the right of the hair just at the entrance to the hair follicle. The fine, black, threadlike lines running roughly parallel to the surface and to be found throughout the thermostat layer are the elastin fibers, or yellow fibers of connective tissue. In this layer, the collagen fibers are very much finer than in the reticular layer and appear to be broken up into individual fibrils. The grain surface appears only as portions of tiny fibrils with no sharp line of division from the rest of the derma. No papillz are to be seen in this section; in fact, we found no papillz in any part of the cow hide, except in the region of the legs.
In order to present a still clearer picture of the important thermostat layer, we prepared series of sections parallel to the surface of the hide. Strips of hide imbedded in paraffine were placed in the microtome and sections, each 20 microns thick, were cut in succession from the corneous layer to a point in the reticular layer, every section being kept in order and mounted. The five horizontal sections shown in Figs. 13 to 17 were prepared from a strip of hide taken from the thigh so as to include the papillz, which were not present in the other regions. Fig. 13 is a section cut through the epidermis. In the
the center is the cross section of a hair. The stringy lines forming an oval shaped mass about the hair are the part of the corneous layer of the epidermis which dips down into the hair follicle. The heavy dots seen throughout the rest of the picture are the nuclei of the cells of the Malpighian layer of the epidermis. The irregularly shaped, light-colored patches are cross sections of the papille of the derma
Fig. 14 represents a section cut 0.30 millimeter below the upper surface of the corneous layer. It marks the plane of the derma where the ducts of the sebaceous glands empty into the hair follicles. In
the lower part of the middle of the picture can be seen the cross section of a hair and of two ducts emptying into the follicle, just above the hair, to right and left. Both the ducts and the follicle are lined with epithelial cells which are continuous with the Malpighian layer of the epidermis and of which they are appendages. The dark, thread-
being stained more lightly, are not prominent.
The section in Fig. 15 forms the plane 0.24 millimeter below that of Fig. 14. The hair whose cross section is shown in the lower part of the middle of Fig. 15 is the same as that shown ite bigs dee Loe
Location: thigh. Eyepiece: none.
Thickness ot section: 20 ,. Objective: 16-mm. Stains: Van Heurck’s logwood, Wratten filter: H-blue green. Daub’s bismarck brown. Magnification: 48 diameters.
hair follicle at this point has a much thicker wall of epithelial tissues and is more thickly bound by elastin fibers. Above the follicle, to the right and left, are the two groups of sebaceous glands whose ducts can be seen emptying into the follicle in Fig. 14. These glands resemble bunches of grapes. Each dot is a cell nucleus and the fine
lines are the thin walls bounding the cells. A portion of the erector pili muscle is visible at the midpoint of the top of the picture. It is passing obliquely upward through the plane of the section and away from the hair follicle. The contraction of this muscle exerts a pressure upon the cells and their oily contents are forced up through the ducts
and into the hair follicles at the openings shown in Fig. 14. Between the two groups of glands and the hair follicles is a mass of muscle tissue of the same kind as that constituting the erector pili muscle. Apparently the muscle extends also into this region and exerts its pressure upon the cells by a sort of pinching action.
Fig. 16 is a photomicrograph of this section taken at lower magnification so as to show the general arrangement of follicles and glands. The portion appearing in Fig. 15 can now be recognized just below the center of the picture. Associated with the hair we have been following are three others, and this tendency for the hairs to group themselves in threes and fours is very noticeable. Some of the follicles are not so deeply seated as others and have their sebaceous glands in a plane higher up. This explains why no glands are to be seen in the vicinity of some of the follicles. The short, thick lines appearing here and there are arteries or veins wandering in and out of the plane of the section.
In Fig. 17 is shown the section forming the plane 0.30 millimeter below that of Fig. 15, or a total distance of 0.84 millimeter from the upper surface of the corneous layer. A cross section of the same hair as that shown in Figs. 14 and 15 appears in the center of the picture, but this time we have cut right through the hair bulb. The black mass is the bulb and the light patch at its center is the hair papilla. To the right and left and above the hair bulb are the sweat glands. They appear as large, empty sacs, with portions of their linings of epithelial cells showing like leopard spots. In this plane the elastin fibers are much less numerous than in the regions higher up and the collagen fibers are now much larger and grouped in bundles. At a distance of 0.12 millimeter below this plane, we encounter the last of the epithelial cells of the sweat glands and therefore the lower boundary of the thermostat layer. :
The reticular layer consisted almost entirely of collagen fibers, elastin fibers being present only in the lowest region and surrounding the blood vessels and nerves traversing other parts of the reticular layer.
Calf Skin.
A calf skin, very naturally, appears much like a cow hide in miniature. In Fig. 18 is shown a vertical section from the skin of a healthy young heifer calf, which had been fixed in Erlicki’s fluid immediately following the slaughter and flaying of the animal. As a rule, the skin of a heifer calf has greater solidity and fineness of appearance than that of a steer calf and is, consequently, to be preferred for leather making. In comparing Figs. 11 and 18, it should not be overlooked that the section of calf skin is magnified more than twice as highly as that of the cow hide. In fact, in making comparisons of any photomicrographs in the book, erroneous conclusions may be drawn, if the magnifications are not taken into consideration.
skin is noticeable. This fact is doubly interesting because the structure of this layer is of much greater importance for calf skin than for cow hide; calf skins are generally used to make dressing and other leathers where fineness of appearance of the grain surface is highly valued, while cow hides more often are used for sole, belting, and harness leathers.
Another point to be noted in comparing Figs. 11 and 18 is that the sections were cut from exactly corresponding parts of the skins of the two animals. The importance of this point will be made clear from a study of Figs. 20 to 27. It is well known that a tanned skin is not uniform in structure throughout its entire area. The ‘butt is usually much thicker and has greater solidity than any other part. The ~ shanks are firm, but thin, while the flanks are thick, but spongy. In
are shown in Figs. 20 to 27. The reticular layer is - ee shank ; ee ae shank ; nearly 3 times as thick in the seuencuidert PAs ete butt as in the hind shank. In 7: butt; 8: tail. the shoulder, the reticular
layer is thinner than that
of the butt and its fibers are somewhat finer. In the belly, the collagen fibers run nearly parallel to the grain surface and offer little resistance to any tendency to pull them apart in a vertical direction, whereas many of the fibers in the butt run nearly vertically, with some running in almost any direction, making this region very resistant to distortion.
of the living skin.
In studying Fig. 18, use may be made of practically the entire description of cow hide given above. The bottom fifth of the picture shows the adipose tissue, consisting of rows of fat cells held together
mimeo LOG SLOP eS KIN 51
by strands of connective tissues. The thick band forming the lower boundary of the derma is closely interwoven with elastin fibers, but between this region and the thermostat layer, as in the cow hide, there are very few elastin fibers.
A better view of the fibers of the reticular layer may be had by referring to Fig. 8, which shows some of the fibers appearing at the left hand side of Fig. 18, but at a much higher magnification.
Fig. 28 shows a vertical section of the skin of a healthy sheep,
fixed in Erlicki’s fluid immediately after the death of the animal. Its ' structure is very different from that of the calf skin, both in the thermostat and reticular layers. A comparison of Figs. 18 and 28 indicates very plainly why sheep skin cannot be substituted for calf skin, where firmness and substance are desired. The collagen, or leather-forming, fibers of the sheep are extremely thin and not closely interwoven and tend to run parallel to the skin surface, which in itself makes for looseness of texture. Moreover, in the thermostat layer there are numerous sweat glands and fat cells, which leave empty spaces in the finished leather and make it very spongy
The proportion of fat cells to collagen fibers in sheep skins varies considerably according to the feeding of the animal, and there is often to be: found an almost continuous layer of fat cells separating the two main layers of the skin. In such cases, it 1s desirable to separate the skin into its two layers before tanning and to tan each separately rather than to try to keep them together. Usually the skins are split into two parts after the liming process and the thermostat layers, called grains, are tanned with sumac or other tanning extract to make leather © suitable for bookbinding, hat bands, etc., while the reticular layers are converted into chamois leather, for which they are particularly suitable, by means of a tannage with cod oil.
The dark, curved mass, very prominent in the upper, right hand of the picture and the smaller masses of similar appearance are portions of hair follicles. Unlike the follicles of the calf, those of the sheep turn and twist in every direction. We were unable to find one follicle lying wholly in a single plane. The curvature of these follicles is responsible for the curliness in the wool of the sheep. In _ the cow and calf, the hair is straight because the follicles are straight.
The twisting of the follicles makes the study of the structure of sheep skin more difficult than that of the calf. But the examination of several sections is sufficient to show that the general mechanism of the two skins is the same. Running from the top of the portion of hair follicle showing in the upper right part of the picture is a part of an erector pili muscle. The sebaceous glands appear to be very near the surface, while the sweat glands occupy much of the lower portion of the thermostat layer.
Vertical Sections of Calf Skin. : Locations: as noted. Eyepiece: none. Thickness of sections: 15 wu. Objective: 32-mm. Stains: Van MHeurck’s logwood, Wratten filter: F-red. Picro-indigo-carmine. Magnification: I5 diameters.
Vertical Sections of Calf Skin. Locations: as noted. Eyepiece: none. Thickness of sections: 15 wu. Objective: 32-mm. Stains: Van MHeurck’s logwood, Wratten filter: F-red. Picro-indigo-carmine. Magnification: 15 diameters.
nection with the study of the raw skin. The epidermis can be differentiated more clearly by comparing Fig. 28 with Figs. 66 and 67 of Chapter 8. The general arrangement of the elastin fibers is best shown in Fig. 83 of Chapter 9. 3
The specimen of sheep skin shown was unusually free from the fat cells that tend to separate the skin into two layers. We were able to tan it into a reasonably firm piece of leather, A section of this leather is shown in Fig. 104 of Chapter 13. The leather was soft and somewhat spongy, but is probably a good example of the type of skin often substituted for kid skin in the manufacture of glove leather.
In many respects the skin of the goat may be regarded as having a structure intermediate between that of the calf and the sheep. The fibers are fuller and firmer than those of the sheep, but are hardly equal to those of the calf. The glands and fat cells, which are responsible for the sponginess of sheep leather, are very much less abundant in goat skin, although it must be admitted that this is largely dependent upon the animal’s feeding. Both the goat and the sheep skins of the general market vary widely in quality and substance, a fact which warrants a considerable extension of the study of their structures. Calf skins, on the other hand, do not vary in quality nearly so widely. |
Like the calf, the goat has straight follicles, and, consequently, straight hair. The surface of goat skin is very much coarser than that of calf skin. A glance at Fig. 9 will show that the pattern of the calf grain is considerably finer, even than that of the kid. Roughness of grain, however, is sometimes desirable and the grain surface of goat skins is often made still coarser by mechanical means,
A vertical section of kid skin is shown in Fig. 29. This was just an average domestic skin in the condition in which fresh skins are usually received at the tannery. The epidermis is the very thin dark line forming the upper boundary of the skin. It dips down into the derma, forming a nearly straight follicle, in which the hair grows. The erector pili muscle is the thin fine running upward to the right from the base of the follicle. The opening of the sebaceous glands into the follicle can be seen just above the erector pili muscle. The fact that the collagen fibers run nearly parallel to the surface gives this skin, in its most solid part, a softness and looseness found only in the flanks of the calf skin. |
Bounding the lower surface of the derma is a layer of striated muscle tissue, which permits the animal to twitch its skin. Muscles of this kind are often found on most of the various kinds of skins used for making leather.
A typical section of chrome tanned goat skin is shown in Fig. 146 of Chapter 14. It is interesting to compare its general structure with those of the calf and sheep.
reticular layer is composed chiefly of fat cells, which have practically no value in making leather. We have here a case where the general use of the term reticular is apt to be misleading. The close relation of this structure to that of the human scalp, shown in Fig. 1, should be noted.
The epidermis, as well_as the upper surface of the derma, is very rough and irregular in appearance. As in other skins, the epidermis dips down into the derma, forming the follicles in which the hairs,
structure of a hair bulb from the hog is shown in Fig, 5.
The erector pili muscle belonging to the follicle shown in Fig. 30 did not lie in the plane of the section. A portion of one of these muscles can be seen in Fig. 84 of Chapter 9, which, because of its very much higher magnification, also shows the arrangement of the elastin fibers of the thermostat layer. The hog has relatively much fewer elastin fibers than the cow, calf, or sheep. :
The roughness of the surface of the derma is further accentuated by the presence of papillae, which seem to be rare in the skins of most of the lower animals studied. In the cow hide, papille were found only in the region of the legs, while in the calf, sheep, and goat skins, no papillae were found at all. It would be interesting to determine whether the abundance of papille makes the hog more sensitive to touch and pain than the other lower animals. The extreme roughness of the grain surface of tanned hog skin is very noticeable in Fig. 9.
After the skin has been unhaired and prepared for tanning, only a portion of the thermostat layer remains. The follicles then are simply pockets lined with the grain membrane, the lower portions protruding out from the under side of the skin. When the tanned skin is shaved down on the under side to make it smooth, the bottoms of these pockets are cut away, leaving holes wherever there were bristles in the original skin. This serves further to lower the value of leather made from hog skin. A section of tanned hog skin is shown in Fig. 107 of Chapter 13.
The outstanding peculiarity of horse hide lies in the reticular layer. In the region of the butt there is a dense mass of collagen fibers in the reticular layer so compact as to render leather made from the butt naturally waterproof and nearly air tight. A section of horse hide taken from the butt is shown in Fig. 31. The dense mass of fibers, often called the glassy layer, can be seen running horizontally across the middle of the picture and appearing much darker than the remaining fibers. The portion of the hide containing the glassy layer is known as the shell and is used to make the leather sold under the name of cordovan. The rest of the hide not only does not have this glassy layer, but the fibers of the reticular layer are very loosely inter-
The thermostat layer of horse hide resembles that of cow hide. The general arrangement of the hair follicles, the erector pili muscles, and the sebaceous glands can be seen in Fig. 31, but the full detail shown in the sections of cow hide is lacking because the specimens of horse hide were not fixed immediately after the death of the animal, as in the case of the cow hide. The section, however, represents a hide in probably the usual condition in which horse hides are received at the tannery.
Figs. 105 and 106 of Chapter 13 show a comparison of leather made from the shell and that made from the portion of hide immediately adjoining the shell. In splitting the leathers to a nearly uniform thickness, the knife of the splitting machine cuts through the lower part of the glassy layer. ‘lhe greatest contrast between the two specimens is thus shown in the lower portions.
Guinea Pig Skin.
A section of guinea pig skin is shown in Fig. 32 as an example of very small skins. Such skins can be made into fairly good leather, but their diminutive size limits the demand for them and it is questionable whether such leather could be sold at a profit. A point worthy of note is that the thermostat layer of the guinea pig skin is of practically the same thickness as that of a calf skin, which is very much larger. As shown in the description of the different parts of the calf skin, when nature provides a thinner skin, she does so almost entirely at the expense of the reticular layer, and not of the thermostat layer. It is possible that a mininium thickness for any size of animal is required for the proper operation of this important layer.
The corneous layer of the epidermis appears like a few strands of delicate threads just above the Malpighian layer, the dark line bounding the upper side of the derma. ‘The collagen fibers of the reticular layer are so fine that they appear only as thin threads even at a magnification of 70 diameters. The dark band crossing the bottom of the picture is a mass of striated muscle tissue.
Fish Skins.
The detailed structure of fish skins is very different from those of mammals. Nevertheless fish skins yield a leather comparing favorably with some of the more common types of commercial leathers. Fish leather is very tough, as a rule, and is suitable for many purposes where great strength is required. Sturgeon leather used for lacing heavy belts together has been known to outwear the belts. Tt je said that the people of New England, in the old days, made shoes and gloves from the skin of the cod fish. Other fish skins are sometimes used for making fancy leathers.
Fig. 33.—Vertical Section of Halibut Skin. Fig. 34.—Vertical Section of Cod Fish Skin. Fig. 35.—Vertical Section of Salmon Skin.
skins of the halibut, cod, and salmon. These skins have a thin epidermis covering them and which dips into the derma here and there forming follicles in which the scales grow. The scales of the fish correspond to the hairs of the warm blooded animals. The scales may be recognized by their saw-tooth edges.
A portion of the right hand side of Fig. 35 is shown in Fig. 36 at a very much higher magnification so as to show the detailed structure of the derma. The upper portion of the picture is occupied by the lower end of a scale. We have not yet identified in fish skin the machinery of a thermostat layer like that common to the skins of mammals and, being cold blooded, they probably have none. Instead of interlacing bundles of collagen fibers, ribbons of collagen running parallel to the surface make up the major portion of the skin. These ribbons do not interlace, but here and there we note bands of collagen running vertically through the skin. This adds greatly to the strength of the skin and prevents the distortion made possible in a vertical direction where all the fibers or ribbons run horizontally.
A section of tanned salmon skin, with the epidermal system completely removed, is shown in Fig. 108 of Chapter 1 3. This leather i. purposely shown in the unfinished state because the structure is thus shown more clearly. In finishing such leather, either the loose, upper portion is rolled out smoothly and coated with a finishing material or it is shaved off and the under portion is treated with a suitable finish and embossed or plated.
Other Skins.
The descriptions of skin structure given above are the result of an investigation still in progress and far from complete. But it appears that what has thus far been accomplished represents a real advance and that it is desirable to present as much as possible of what has been learned to date, even though the subject is incomplete. In the chapters on tanning, sections of leather appear which were made from skins of which we have not yet made a study. These may profitably be consulted in connection with the study of histology.
In Fig. 110 is shown a section of alligator leather. The structure of the fibers, or ribbons, in many ways resemble those of the fishes. A somewhat similar structure may be noted in the section of shark leather in Fig. 109. The uninviting hooks on the surface of the shark leather are hardly visible to the naked eye and give the leather a harsh feel. There are, of course, many kinds of sharks and it is not customary to leave these hooks on the leathers placed on the market. The fibrous structure of the horned-toad leather shown in Fig, 111 also resembles that of the fishes. In contrast to the smaller skins is the section of hippopotamus leather shown in Figs. 11 5 and 116.° Other interesting types of leather are those of the camel and walrus, shown in Figs. 112, 113, and 114.
Chemical Constituents of Skin.
By far the greater portion of the solid matter of the skin consists of protein matter. The proteins forra one of the most important and complex groups of organic compounds and are remarkable for the number of general physical and chemical properties which they possess in common and the extreme difficulty of making quantitative separations of the several members of any one group. They all contain carbon, hydrogen, nitrogen, and oxygen, and many of them also contain sulfur and phosphorus. They are all amphoteric, combining with both acids and bases, and those that do not dissolve in water swell by absorbing water. They are more or less readily hydrolyzed by boiling acid or alkaline solutions or by appropriate solutions of enzymes. Hydrolysis proceeds in steps yielding in turn bodies of decreasing complexity, the proteoses, peptones, polypeptides, and finally simple amino acids. Amines and ammonia are often found among the various hydrolytic products. The following amino acids have been isolated and identified from the hydrolytic products of different proteins: ?
Under suitable conditions, amino acids can be made to combine with each other by removing the elements of water, the amino group of one combining with the carboxyl group of another, thus
CH,.COOH,
which contains 15 glycine and 3 leucine residues and has a molecular weight of 1213. It gives the biuret test for protein, is precipitated from solution by tannin, and would have been classed as a protein had it been found in nature. Later Abderhalden and Fodor? succeeded in
and having a molecular weight of 1326.
The close resemblance of the more complex polypeptides to the natural proteins and to their first products of decomposition, the proteoses and peptones, and the fact that all proteins yield amino acids upon complete hydrolysis have established the view that the general structure of proteins is at least similar to that of the polypeptides. The above list of amino acids indicates the tremendous number of possible combinations to form proteins and of the isomeric forms that any individual protein may have.
The generally accepted methods of classifying proteins are based upon differences in solubility, speed of hydrolysis, and precipitability under definite conditions. But, since a small amount of foreign matter may alter these properties entirely for a given protein and because of the difficulty of separating and purifying proteins, this system of classification is not wholly satisfactory, although it is, perhaps, the best available at the present time. The common names applied to proteins, such as keratin, albumin, etc., do not represent individual substances, but groups of closely related proteins whose quantitative separation is very difficult.
The most important classes of skin’ proteins, in the order of increasing importance to the tanner, are the mucins, albumins, globulins, melanins, keratins, elastins, the unnamed proteins of the grain surface, and the collagens. [Except in the case of fur skins, the first five classes are of importance only because they must be removed from the skin prior to tanning, without injuring the remaining protein matter. In general, the albumins are the only skin proteins soluble in pure water. The globulins are soluble in dilute salt solutions and the mucins and melanins in dilute alkalies. The four remaining classes, which belong to the general group of proteins known as albuminoids, are insoluble in dilute solutions of acids, bases, or salts at room temperature, but all are dissolved and hydrolyzed by boiling solutions of concentrated acids or alkalies. The keratins are dissolved by strongly alkaline solutions before the remaining three classes are seriously attacked and the elastins are easily dissolved by trypsin before any injury is done to the collagen or grain surface. In boiling water, the collagen goes into solution as gelatin, leaving behind a residue of elastin and the proteins of the grain surface.
The albumins and globulins are found in the blood and lymph of the skin and also in the fluids of the muscles and nerves. By extracting powdered dog skin with a 10-per cent solution of sodium chloride, under toluene at 37° C., Rosenthal * obtained a quantity of albumins and globulins which, upon coagulating, washing with water, alcohol, and ether, and drying, gave a weight equal to 24 per cent of the total protein of the skin. But a yield of only 4.2 per cent was obtained from calf skin.
acids, bases, and salts, but are precipitated by the addition of concentrated mineral acid or by saturating a weakly acid solution with salt. Their solutions coagulate upon boiling, in the presence of a small amount of salt.
The globulins generally are insoluble in pure water at the neutral point, but dissolve in dilute neutral salt solutions, from which they can be precipitated by sufficient dilution or by saturating the solution with salt, being most readily soluble in salt solutions of moderate concentration. They dissolve freely in dilute solutions of acids and alkalies. Like albumins, their solutions coagulate upon heating. Fibrinogen, an important constituent of the blood, is usually classed as a globulin, but differs from serum globulin in being precipitated from solution by a lesser concentration of neutral salt and of coagulating at a lower temperature. It tends to clot upon exposure to air, forming the insoluble © protein fibrin, which action is favored by rise of temperature or agitation and is hindered by cooling or the addition of acids, alkalies, or concentrated salt solutions. The clotting action is supposed to be due to the action of an enzyme, thrombin, which is not a normal constituent of blood, but which is formed from the leucocytes and blood plates in the presence of calcium salts. .
The mucins are conjugated proteins, of the group known as glycoproteins, containing both protein and carbohydrate groups in their molecules. They are insoluble in pure water, but, in faintly alkaline solution, give mucilaginous solutions which are precipitated by the addition of acid. It is questionable whether mucins are abundant in the skins of mammals. It has often been assumed that the mucins form the elusive “interfibrillary cementing substance” of the skin, but the existence of a cementing substance in the fibers, other than collagen itself, has not been clearly demonstrated.
Rosenthal ® extracted calf skin, previously freed from albumins and globulins, with half-saturated lime water under toluene. Upon rendering the extract acid with hydrochloric, protein matter was precipitated, which was washed with dilute acid, water, alcohol, and ether, and dried and weighed. The yield of protein, which he called mucoid, equalled about 2.7 per cent of the total protein matter of the skin. The yield from the solid part of the butt was 4.8 per cent against only 1.2 per cent for the loose portions of the belly. Although mucoids are dissolved by dilute alkalies and precipitated by rendering the solution acid, doubt is thrown on Rosenthal’s interpretation of his results by the experiments of Thompson and Atkin,® who showed that hair and wool are partly dissolved by lime liquors and that some of the matter dissolved is precipitated by rendering the solution slightly acid. Since the newly formed epithelial cells are very much more easily attacked than hair and wool, much of the material isolated by Rosenthal may actually have been derived from this source. |
and the mucoids. Hammarsten ‘ differentiates between them as follows: “The true mucins are characterized by the fact that their natural solutions, or solutions prepared by the aid of a trace of alkali, are mucilaginous, ropy, and give a precipitate with acetic acid which is insoluble in excess of acid or soluble only with great difficulty. The mucoids do not show these physical properties, and have other solubilities and precipitation properties.”
The melanins are proteins of intense color, usually reddish-brown to black, constituting the pigment of the hair and epithelial cells. They are insoluble in water and dilute acids, as a rule, but dissolve more ‘or less readily in dilute alkalies. They may be extracted with boiling dilute alkali and precipitated by the addition of acid. They contain variable amounts of iron and sulfur in combination.
The origin of the melanins is not known with certainty, although it seems probable that they are derived from the blood and lymph. Their development is accelerated by frequent exposure to strong sunlight. Prolonged exposure is followed by a rush of blood to the skin and the production of pigment to protect the tissues against the action of the intense light. This shows itself in the apparent darkening of the color of the skin. The coloring matter of the blood, hemoglobin, belongs to the class of conjugated proteins known as chromoproteins and, like the melanins, also contains iron and sulfur.
That the blood and lymph contain substances capable of reacting to produce deeply colored bodies is well appreciated by the tanners. Skins from which the blood and lymph have not been washed are liable to develop stains very difficult to remove, unless special precautions are taken, which will be discussed in Chapter 6 in connection with the preservation of skin to be kept for a considerable period before tanning.
The chief constituent of the epidermal system, including the epidermis, hair, and epithelial cells of the glands, is the class of proteins known as keratin. The general method of preparing this material for examination is to boil the finely divided sample containing it with water and then to digest the residue with an acid pepsin solution followed by an alkaline trypsin solution and then to wash it thoroughly with water, alcohol, and finally with ether.
Keratin differs chemically from other classes of proteins in yielding a comparatively large amount of cystine, upon hydrolysis. In the following table are given the yields of amino acids obtained from keratins from different sources along with those from samples of elastin and collagen, or gelatin. The differences shown by keratins from different sources is interesting, but each sample analyzed probably consisted of a mixture of different keratins more or less contaminated by other proteins.
Keratin prepared in the manner described above is naturally very resistant to the action of dilute acids and alkalies, pepsin, trypsin, and boiling water, but it is dissolved by strong alkalies and by water heated
LYSING eae Pee oe I.1 a3 0.2 HM Pee 5.9
to 150° C. under pressure. The method of preparation may be criticized on the ground that it does not include young keratin. On the other hand, it may be contended that the proteins of newly formed epithelial cells are not keratins at first, but are later converted into keratins. However, the changes in properties with age are so gradual as to make it almost impossible to draw any sharp line of demarcation. This is a good example of the difficulty of trying to classify proteins strictly according to properties. The cells of the Malpighian layer of the epidermis are readily attacked by trypsin and by solutions of ammonia, but become very much more resistant as they are pushed upward into the corneous layer.
In the stratum granulosum of the epidermis, the protoplasm of the epithelial cells has dried up and appears like granules inside of the cells. Walker ** regards these granules as consisting of two substances, keratohyalin and eleidin, presumably stages in the transformation of the protoplasm into the wax and fatty material with which the cells of the corneous layer of the epidermis are loaded.
The yellow, elastic fibers interlacing the outer layers of the derma and enveloping the nerves and blood vessels are made up of a class of proteins called elastin. The tendons of the body have been the chief source of elastin used for study, in particular the ligamentum nuche, the tendon at the back of the head of the ox. F. L. Seymour-Jones ™ found that a piece of ligamentum nuche of about 1 square centimeter cross section gave on a testing machine an extension of 150 per cent before breaking, the strain being too small to measure; less than 5 lbs.
although the action may have been due to bacteria.
Elastin may be prepared for study by extracting this tendon with dilute sodium chloride solution, washing and then boiling it with water, then with a 1-per cent solution of potassium hydroxide, again with water, and then with acetic acid. The residue is then treated with cold 5-per cent solution of hydrochloric acid for 24 hours, thoroughly washed with water, boiled again with water, and then washed with alcohol and ether and dried. It then has a yellowish-white appearance. It is not dissolved by boiling water nor by acids and alkalies in the cold, but is easily dissolved by concentrated mineral acids upon heating. The yields of the different amino acids from a sample of elastin are given in Table I.
It is, of course, not safe to assume that elastin from skin has exactly the same properties as that from other parts of the body, but the difficulty of isolating some of the skin proteins for study has made it desirable to investigate proteins of the same general classes from parts of the body where they are more easily available, if only to get a suggestion of the properties of the skin proteins. Actually we do find that the elastin of skin behaves much like that from the ligamentum nuche, being resistant to boiling water and to cold solutions of acids and alkalies. In glue manufacture, much of the elastin remains in the scutch or residue left after boiling the skin in water. By examining sections of skin under the microscope, after special treatments, we have found that the elastin fibers are not appreciably attacked by dilute solutions of acids and alkalies or by tannery lime liquors, but are easily dissolved by neutral trypsin solutions. ‘These fibers apparently act so as to resist an increase in area of the grain surface of the skin.
The proteins of the grain surface are remarkably resistant to most of the ordinary chemical reagents. The thin fibers of this surface are not dissolved by solutions of caustic alkalies sufficiently strong to destroy the collagen fibers, epidermis and hair. In boiling water, they evidently undergo some change in composition, but remain undissolved in the form of a thin sheet while the collagen passes into solution as gelatin. They are apparently unaffected by trypsin solutions strong enough to dissolve all of the elastin fibers beneath them. But in contact with water having a pH value of about 6, they are easily attacked and liquefied by putrefactive bacteria, although this action can be checked by the addition of a sufficient amount of acid, alkali, or salt.
These fibers represent only a very small proportion of the skin by weight, but they are of great importance because they form the grain surface of finished leather, giving it its characteristic appearance. Their position in the grain surface is shown in Fig. 150 of Chapter 106. In tanning and dyeing, they take a color different from that assumed by the collagen fibers, which is noticeable when leather is cut. Any damage to the grain surface reduces the selling value of the leather materially.
Collagen is the most abundant protein of the skin and the one of greatest importance to the tanner, since it is the basis of leather. It constitutes the bulk of the substance of the white fibers of the connective tissues of the derma.
Collagen can be prepared for study from fresh skin by removing the other constituents. The adipose tissue is carefully cut away and the skin thoroughly washed. It is then extracted with several changes of 10-per cent sodium chloride solution, in a closed jar set in a tumbling machine, or agitator, in order to remove the soluble protein matter. It is then put back into the same jar with a one-tenth-per cent solution of sodium sulfide containing lime well in excess of saturation and tumbled occasionally for several days, or until the hair is quite loose.
The hair and epidermal matters are then removed by scraping the grain surface with a knife blade. The entire grain surface is then cut away, preferably on a splitting machine. The skin is then washed thoroughly to remove most of the lime and is then digested for 5 hours at 40° C. with a solution containing 1 gram of U.S. P. pancreatin, 2.8 grams of monosodium phosphate, and 18 cubic centimeters of molar sodium hydroxide per liter. This removes all of the elastin fibers. The skin is then cut into small pieces and put into a jar of water equipped with a stirring device. Hydrochloric acid is added at such rate as to maintain the solution just faintly acid to methyl orange. When no more acid is required, the pieces are left to wash in running tap water over night. Next day they are soaked in several changes of alcohol to remove the water and then in xylene, after which they are exposed to air until the xylene has evaporated. They are then ground in a mill to a fibrous powder. Collagen thus prepared is known as hide powder.
Upon heating with water to 70° C., collagen slowly passes into ~ solution as gelatin. But just what relation gelatin bears to its parent substance collagen is not known with certainty. Hofmeister *® suggested that collagen is an anhydride of gelatin and that the change from one to the other is reversible, collagen being regenerated by drying gelatin at 130°C. This heating changes the properties of gelatin so that it swells in water to a lesser extent than before and passes into solution with greater difficulty. In commenting upon Hofmeister’s work, Alexander *® says “It is extremely doubtful if collagen is regenerated under these conditions, the more probable explanation being that, upon driving off the water, the constituent particles of the gelatin approach so close as to form an irreversible gel, thus rendering it insoluble.”
C. R. Smith 17 found that gelatin dried at 100° C. and then heated to 128° loses 1.25 per cent in weight. It then swells very slowly and dissolves in water at 35° to 40°, with nearly complete restoration of its jellying power. He concedes that gelatin dried at 128° may
be converted into collagen, but that collagen itself may represent a form of gelatin which is difficult to disperse. Emmett and Giles,’ on the other hand, suggest that the conversion of collagen into gelatin involves an intramolecular rearrangement.
Plimmer ¥° says “those proteins which are resistant to the action of trypsin until they have been acted upon by pepsin will have all their units contained in the anhydride ring.” Gelatin is easily hydrolyzed by either pepsin or trypsin, while it has been generally believed that collagen is hydrolyzed by pepsin, but not by trypsin. This led the author 2° to suggest that Plimmer’s statement corroborated Hofmeister’s view of the anhydride structure of collagen. But Thomas and Seymour-Jones ** have recently demonstrated that collagen is attacked by trypsin under the right conditions. The erroneous view that collagen is resistant to tryptic digestion unless previously swollen with acid or alkali dates back to a series of studies by Kuthne,?* Ewald and Kuhne,?? and Ewald,?* which were based only upon qualitative observations.
found that trypsin acts most rapidly upon collagen at a pH value of 5.9 and that the action is not appreciably accelerated by soaking the protein previously in solutions of higher ‘or lower pH values such that the protein is not actually hydrolyzed by the acid or alkali. In studying _—the effects of time and concentra- ; en At :
In each experiment 0.5 gram of
hide powder was placed in a centrifuge tube having a capacity of Io cubic centimeters and a conical bottom graduated in units of 0.1 cubic centimeter. In order to bring the hide powder to the optimum pH value, they covered it with 5 cubic centimeters of a phosphate buffer solution having a pH value of 5.9 and a few drops of toluene to check bacterial action. The tube was shaken for 3 hours, then centrifuged for 20 minutes at 1000 times gravity, and the volume of hide powder read from the
graduations in the tube. The supernatant liquor was then run away and replaced by 5 cubic centimeters of trypsin solution having a pH value of 5.9 or by the buffer solution where a blank was being run. Toluene was added in every case as a safeguard. The solution was shaken in a thermostat at 40° C. for a stated length of time and then centrifuged and the volume of hide powder again read, the loss in volume being taken as a
measure of the amount of hide powder dissolved. | The rate of digestion of hide powder by a 0.5-per cent trypsin solution is shown in Fig. 37 as a function of the time. With a solution so concentrated in enzyme, hydrolysis takes place extremely rapidly. It is interesting to note -
6 Bipe hide oonabes also the steady hydrolysis in the se iat 1 blank (without enzyme) at 40° C. time = 30 mine, In Fig. 38 are shown the rates
of digestion of fine and coarse hide powders as functions of the concentration of enzyme. The fine powder consisted of the portion passing through a sieve of 34 meshes to the: inch and the coarse powder of the portion retained by the sieve. A much longer time is required to hydrolyze the coarse powder, as was expected. In Chapter 8 it will be shown that a concentrated solution — of trypsin produces marked hydrolysis of calf skin only after acting for nearly 40 hours. Here the time required for diffusion of the en-’ 100 200 300 400 500 600 zyme into the skin and complicamiviigrens of Trypsin per Liter tions due to the presence of preteia
Fig. 38.—Rates of digestion of fine matter other than collagen play a and coarse hide powders as func- part. In the method described above tions of the concentration of tryp- for preparing collagen for study, the a action of the enzyme does not result in any very serious loss of collagen, but all of the elastin is digested. Collagen is hydrolyzed by concentrated solutions of acids and alkalies
in the cold, if sufficient time is allowed. Upon heating the solutions, the hydrolysis proceeds rapidly. In a study of the hydrolysis of gelatin by acids, alkalies, pepsin, and trypsin, Northrop *® found that the course of the early stages of hydrolysis is similar with alkali, trypsin, and pepsin, but quite different with acid. He made a comparison of the relative velocities of hydrolysis of the various peptide linkings and observed the following important facts. Those linkages which are hydrolyzed by pepsin are also hydrolyzed by trypsin; but trypsin hydrolyzes linkages which are not attacked by pepsin. Of the linkages hydrolyzed by both enzymes, those most rapidly hydrolyzed
by pepsin are only slowly attacked by trypsin. Those linkages which are most rapidly split by pepsin or trypsin are among the more resistant to acid hydrolysis and least resistant to hydrolysis by alkali.
The chemistry of collagen and gelatin forms so large a portion of the chemistry of leather manufacture that further treatment must be reserved for the appropriate chapters.
The skin contains a number of non-protein substances in the blood, lymph, and gland secretions. The blood and lymph contain sugars, salts, particularly the phosphates, carbonates, sulfates, and chlorides of sodium and potassium, and fatty matters, including cholesterols and the lecithins, which are phosphorous compounds of fats often existing in loose combination with proteins. Sodium chloride is the chief constituent of perspiration, which also contains sulfates, phosphates, and urea, and sometimes sebum. Sebum, the secretion of the sebaceous glands, consists of cholesterols, complex oleins, higher alcohols, and soaps, and is usually found contaminated with epithelial cells, probably those of the sebaceous glands furnishing the sebum.
Of vital importance in the use of tannery liquors is the-control of hydrogen-ion and hydroxide-ion concentrations. Irregular variations in these concentrations are almost certain to result in corresponding irregularities in the properties of the leather produced. By juggling the methods of operation until a nearly uniform product was obtained and then rigidly adhering to a developed process, tanners long ago perfected means for keeping hydrogen-ion concentrations reasonably well under control, although without any appreciation as to why certain steps had to be followed. If liquors suddenly became infected with acid-producing ferments, or got beyond the control of the operator from other causes, the result was apt to be disastrous unless the tanner had learned from similar experiences how to correct the trouble.
Many of the pioneers who attempted to introduce chemical methods to the industry were handicapped by their inability to compare the activities of acids or bases of different strengths. Too much reliance upon the total concentration of acid, with little or no appreciation of its degree of ionization, has often proved very misleading. It is still not uncommon to find expensive acids being used where cheaper ones would serve the purpose as well or better. Even where an operator had come to appreciate that the determining factor was the hydrogenion concentration rather than the total titrable acidity, he was often without the means for determining hydrogen-ion concentrations and there were no easily available figures showing the degrees of ionization of the commoner acids and bases at different concentrations. In order to remedy this situation, Thomas * computed and compiled from the literature a series of tables showing the degrees of ionization of a number of acids and bases commonly used in the tannery; a range from 0.001 to 2 molar is covered. These tables are incorporated in this chapter because it is believed they will make certain portions of the book more readily comprehensible to a greater number of readers and will prove of great value for reference in experimental work on leather manufacture.
But, since the value of K*V? is negligible compared to KV, it can be dropped for the purpose of making the calculations. The following expression, therefore, was used:
For the strong acids, the experimentally determined values for 1ooa at various concentrations were found in the literature. These were plotted against values for logV and a smooth curve was drawn through the points. The desired values were then read from the curve. The hydroxide-ion concentrations of bases were obtained similarly.
The figures in the tables may be in error as much as 5 per cent, especially in the cases of the strong acids and bases, but they are the best obtainable at this time. They were obtained from conductivity data and not from measurements by the hydrogen electrode.
Boric Acid.—Calculated from K = 6.6 X 10719 at 25° C. by Lunden.* 0.8 molar is saturated solution and since this acid is exceedingly weak, only the concentrations at 0.8, 0.1, 0.01, and 0.co1 molar are given in the table.
Butyric Acid.—For concentrations 2 to 0.1 molar, calculated from Poet tO «6at 25° by Ostwald* From 0.1 to 0.001 molar calculated from Ostwald’s experimental values. |
Carbonic Acid.—This acid is very weak and its concentration in solution depends upon the pressure of carbon dioxide on the surface of the solution. For this reason no special table was prepared and only two significant concentrations are given here, taken from Kendall.® At 25° the solubility of carbon dioxide in water at 1 atmosphere of pressure of carbon dioxide is 0.0337 mole per liter. The carbonic acid in this solution is 0.33 per cent ionized and hence its concentra-
tion of hydrogen ion is 0.coo11 mole per liter, representing a pH value of 3.96. Under ordinary conditions, the partial pressure of carbon dioxide in the air is 0.000353 atmosphere, at which pressure carbon dioxide is soluble to the extent of 0.0oooo11g mole per liter, yielding a hydrogen-ion concentration of 0.000002 mole per liter or a pH value of 5.70.
Citric Acid.—For 2 to 0.4 molar, the values of Kendall, Booge and Andrews ® are given. From 0.4 to 0.1 molar, the values are extrapolated. From 0.01 to 0.001 molar, the concentrations are calculated from the measurements of Walden.’
Formic Acid.—From 2 to 0.1 molar, the values are calculated from KS A ee ae evel ue Ostwald. From 0.1 to 0.001 molar, they are calculated from Ostwald’s experimental determinations.
Gallic Acid.—From I to 0.03 molar, values are calculated from K = 4.0 X Io, as given by Ostwald. From 0.03 to 0.001 molar, values are calculated from Ostwald’s experimental values.
Hydrochloric Acid.—The figures for 2 to 0.5 molar are from Jones. Those for 0.5 to o.oor molar are calculated from Kohlrausch’s ?° experimentally determined values.
Lactic Acid.—The figures for 2 to 0.1 molar are based upon the figures of Kendall, Booge and Andrews; ® those for 0.1 to 0.001 molar are calculated from the experimental values of Ostwald.®
Oxalic Acid.—The only data available are those of Ostwald,® covering the range only from 0.03 to 0.004 molar. This acid is too highly ionized to permit calculations by the dilution law.
Phosphoric Acid.—Figures for 2 to 0.1 molar are calculated from the data of Kendall, Booge and Andrews; ® those from 0.1 to 0.001 molar from the experimental data of Noyes and Eastman.™
Tartaric Acid.—From 2 to 0.04 molar, the figures are calculated from the data of Kendall, Booge and Andrews;® from 0.04 to 0.001 molar, they are calculated from Ostwald’s ® experimental data.
Bases.
Ammonium Hydroxide.—tThe figures for this weak base are calculated, by means of the dilution law, from K = 1.8 X 10° at 25° C., as given by Noyes, Kato and Sosman.’.
upon which the calculations in the table are based.
Calcium Hydroxide.—No series of experimental data for this base could be found, but it is so similar to barium hydroxide that probably no great error would arise from the use of the barium hydroxide figures.
Potassium Hydroxide.—The 2 molar value is from Jones. Values for I to 0.4 molar and from 0.03 to 0.001 molar are calculated from Kohlrausch’s '° data; those between 0.4 and 0.03 molar are obtained by extrapolation.
Temperature.
__ All of the ‘values given in Tables II to X are for a temperature of 25°C. The temperature coefficient of ionization is small enough to be neglected for most practical purposes. The figures may, therefore, be considered valid for the range of temperature met with in the tannery.
pH Values.
The term pH value is now widely used to indicate the value of a, with change of sign, in the expression [H"] = 10+ moles per liter. The use of this term has proved confusing to some because an increasing pH value indicates a decreasing hydrogen-ion concentration. But the pH scale has proved of great value for the operator with no knowledge of chemistry. He accepts it as a standard scale of acidity and alkalinity, as he does a thermometer for temperature, without caring about its mechanism. He learns, for example, that a given liquor works best at a pH value of 5.5. When the analyst reports to him a value for this liquor of 6.5, he immediately appreciates that the addition of acid is necessary to bring the liquor back to 5.5. The routine worker adopts the pH scale almost as easily as any other system
of acid Per cent Moles Ht Percent Moles H* per liter ionized perliter pHvalue ionized per liter pH value O.00 Pac dt ee 100.0 0.0010 3.00 100.0 0.0010 3.00 OD02 Beta ee eee 100.0 0.0020 2.70 99.5 0.0020 2.70 O004 2 kn fee 100.0 0.0030 252 99.5 0.0030 2.52 OO0A Tins oa 100.0 0.0040 2.40 ° 99.4 0.0040 2.40 DOOGL i tee ee 100.0 0.0050 2.30 99.4 0.0050 2.30 C.00020 sot esha. 100.0 0.0060 3.22 99.4 0.0060 2.22 OOTP Eas Shtrase 100.0 0.0070 215 99.3 0.0070 2.15 P0080 15s as eee 100.0 0.0080 2.10 99.3 0.0079 2.10 G.000 726 ween cae 99.9 0.0090 2.05 99.3 0.0089 2.05 MOUs cee panes 99.8 0.010 2.00 99.3 0.010 2.00 O02) ccs Bt 98.8 0.020 1.70 99.3 0.020 1.70 O03. .6 0 eee 98.0 0.029 1.54 99.2 0.030 1.52 GA ae ern 97.6 0.039 1.41 08.7 0.039 1.41 O08 aie ete oan 96.8 0.048 142 08.3 0.049 1.31 AR 8 «Pompe ens ioe OR 06.4 0.058 1.24 97.6 0.059 1.23 OTE er fete 95.8 0.067 17 97.3. + 6.068 1.17 CV: wet htae c ee ee 95.6 0.076 Hi2 96.8 0.077 I.II COON eee 95.2 0.086 1.07 06.3 0.087 1.06 re SOR EE Riba 5 Cave 94.8 0.095 1.02 96.0 0.096 1.02 FO.Si 28 ko ae 92.0 0.184 0.74 92.9 0.185 rae ee ate aN ieies ieee 90.1 0.270 0.57 90.7 0.272) 2 aes G.dsdts oe anes 88.7 0.355 0.45 89.4 0.358 0.45 OR eek ee ee 87.5 0.438 0.36 87.9 0.439 0.36 OD eins cies 86.5 0.519 0.28 aie gee Soa OF eee 84.7 0.593 0.23
IONIZATION OF ACIDS AND BASES SI
of measurement. He soon learns that pH = 7 represents a neutral solution, that values increasing from 7 indicate an increasing alkalinity and values decreasing from 7 an increasing acidity.
The investigator in leather chemistry finds it logical to plot variables against —log[H"] rather than against actual hydrogen-ion concentrations because of the enormous range covered. For him the adoption of the pH scale has the advantage of eliminating the use of negative values and making his system of record conform to one more desirable for making plant reports, where the use of logarithms, negative values, and conceptions of ionization are often apt to lead to hopeless confusion.
of acid Per cent Moles H* Percent Moles Ht per liter ionized perliter pHvalue ionized perliter pH value PEQOT ONE Ge 6 a wu iste 07.7 0.0020 2.70 89.0 0.0009 3.05 RIO os es erate were DAF 0.0038 2.42 83.0 0.0017 Pte SNA eS ores oe o's 90.5 0.0054 2.27 ee 0.0023 2.64 TE a eae 88.0 | 0.0070 2.15 73.5 0.0029 2.54 ORT tases «oes s 85.90 0.0086 2.07 70.0 0.0035 2.46 Dis aes 84.2 0.0101 2.00 67.5 0.0041 2.39 ia <j re 82.7 0.0116 1.04 65.0 0.0046 2.34 lS ie ar 81.8 0.0131 1.88 63.0 0.0050 2.30 Marin vin ie 80.5 0.0145 1.84 60.5 0.0054 2:27 Dees wai le am 709.6 0.016 1.80 59.0 0.006 2.23 Tyo) 55 aa a aa 73.1 0.029 1.54 47.5 0.010 2.00 Oe Ss ere en's 69.4 0.042 1.38 42.0 0.013 1.89 5 2.0] See eR ara 66.8 0.053 1.28 38.0 ~~ 0.015 1.82 ne eeedes shies es 64.8 0.005 1.19 35.0 0.018 1.74 TICE oa eae 63.5 0.076 1.12 33.0 0.020 1.70 Ct a ki. G24~. 0.087 1.06 31.0 0.022 -1.66 Se Sree gis, ve 61.7 0.099 1.00 ,30.0 0.024 1.62 OO ence nd, aie tl5 -s 61.1 0.110 0.96 28.5 0.026 1.58 Te es 2 ee 60.7 0.121 0.92 275 0.028 1.55 i bie Seyi eee 57.6 0.230 0.64 22.8 0.046 1.34 Ee a a 56.0 0.336 0.47 20.7 0.062 1.21 Oo; Saas ee 54.7 0.438 0.36 19.8 0.079 1.10 CL Sie tees ic kee.» 54.6 - 0.536 0.27 19.0 0.095 1.02 TT tl Oe 52.9 0.635 0.20 18.8 0.113 0.95 EU ReMi Sicbn Fo: 52.0 0.728 0.14 18.0 0.126 0.90 OS er ork ess 51.4 0.822 0.09 17.9 0.143. > 0.84 a nl a ee ne 50.9 0.916 0.04 17.7 0.159 0.80 icin aoe 50.7 1.014 — 0.01 17.5 0.175 0.76 CS EN Oe 39.9 1.596 — 0.20 16.1 0.322 0.49
per liter ionized perliter pHvalue ionized =perliter pH value St a 18.7 0.00019 3.72 30.9 0.00031 3.51 10 Dn 13.4 0.00027 3.57 23.0 0.00046 3.34 I Pa 10.7 0.00032 3.49 18.7 0.00056 3.25 Sa ¢ ae 9.3 0.00037 3.43 16.7 0.00067 3.18 MERE Mears 5 vss 8.4 0.00042 3.38 15.1 0.00076 Baie “Pan Pe ee vane: 0.00046 344 13.9 0.00083 3.08 Ue Seo 7.0 0.00049 S21 12.9 0.00090 3.05 TCS hig as, eae ee 6.7 0.00054 ‘327, 12.2 0.000098 3.01 PRM oe. en 6.2 0.00056 3.25 11.5 0.00104 2.98 ER ems oe oc 5.9 0.00059 2.28 11.0 0.00110 2.06 Tha Clr ae ae 4.1 0.00082 3.09 8.0 0.00160 2.80 Oe een ee is 5 0 oR, 0.00099 3.00 6.6 0.00198 2.70 SOY he oo eee 3.0 0.00120 2.92 5.8 0.00232 2.63 GR eg once als « s 2.70 0.00135 2.87 5.2 0.00260 2.58 CRC. 8 2.50 0.00150 2.82 4.8 0.00288 2.54 RO eric?
of acid Percent Moles H* Per cent Moles H* per liter ionized __ per liter pH value ionized per liter pH value O.00Ts ela aan II.4 0.000II 3.06 0.080 0.0000008 6.10 O.002 7 oe oe 8.3 0.00017 3.77 rath: ae O.003 S358 6.8 0.00020 3.70
ODOStor ea 5.4 0.00027 3.57
O.000 Fi. ce veo 4.9 0.00029 3.54 CUOkst cieeree 4.55 0.00032 3.49 enees ae See OGOOSi0% os sorces 4.3 0.00034 3.47 ‘eit ey P tate ODOG Pesan ures 3.05 0.00036 3.44 Se oe eee oat O.0l 2o2,ce ares 3.8 0.00038 3.42 0.026 0.0000026 5.58 0,022 in oe 27 0.00054 327 lee : pha OWI ee eee aoe 0.00066 3.18
OP Oia ee 0.49 0.00294 2.53
ER eer Roe 0.43 0.00301 2.52 one poe ee Oo ee eh ewan 0.41 0.00328 2.48 0.003 0.0000240 4.62 O10). Fok ae soe 0.40 0.00360 2.44 AOE arnt or LOS nae 0.39 0.00390 2.40
of acid Per cent Moles Ht Percent MolesHt — per liter ionized perliter pHvalue ionized perliter pH val O.00T ears ieee ss sake wie % Beue. 62.0 0.0006 0.002..... Gop a Tee poe pone 51.0 0.0010 0.003..... Ree er Beer eed seo 44.5. 0.0013 0.004...... etek SO 0.0038 2.42 40.0 0.0016 — OOS eta. ee Ne COs. 0.0047 2.33 37.0 4% ..0.001g 0.006..... ay PE ep 0.0055. 2.26 34.5 0.0021 O,007 22% = ee re eae sa 0.0063 2.20 32.0 0.0022 O.005 sees eee 89.0 0.0071 2.15 30.5 0.0024 0.000 awe ak OG. O.0070.= “2 2.00 29.0 0.0026 DOIG oie ry ee COTO 0.0087 2.06 7 Be 0.0028 . O.0TOTae. ca: baqorene bees Wet Be Sey 24.0 0.0040 0.020 Reis See cea 670) 0.0158 1.80 creak Pr es O80 Ras cite een i ae 0.0221 1.66 Pa gies
of base Per cent Moles OH’ Percent Moles OH’ per liter ionized __ per liter pH value ionized jperliter pH value O00 Tete tea 12.52 0.00013 10.11 96.0 0.0010 11.00 O02 oie oan 8.90 0.00018 10.26 95.0 0.0019 11.28 0.009 Sis aw ee es 7.44 0.00022 10.34 04.0 0.0028 11.45 O.00d 56.5, Sat eer 6.48 0.00026 10.42 93.0 0.0037 11.57 CLOOSTe. aes 5.82 0.00029 10.46 92.0 ~ 0.0046 11.66 C.0062 ig? ates 5.33 0.00032 10.51 91.3 0.0055 Higa D007 E fo pe trate 4.93 0.00035 10.54 91.0 0.006 11.78 OO089 Fa O.et 4.62 0.00037 10.57 90.5 0.007 11.85 C000: a tees 4.37 0.00039 . 10.59 90.0 0.008 11.90 UT) See he Pathe 4.15 0.00042 10.62 88.4 0.009 11.95 O02) Tarte ca a 2.96 0.00059 10.77 86.0 0.017 12.23 DO s 370 as ok 2.42 0.00073 10.86 82.8 0.025 12.40 OOF Bad Sao 2.12 0.00085 10.93 81.0 0.032 12.51 Oa hess ee 1.88 0.00094 10.97 80.0 0.040 — 12.60 QAM sice 2 ace oe ere 0.00103 II.01 ae ee Accmeae 0.07% 432 ines a 1.59 O.0OI II 11.05 O.OR sib. snip 1.49 0.00119 11.08 O008cmt oss ats 1.40 0.00126 II.10 Ope ae seca 1.33 0.00133 II.12
Gowers we 0.60 0.00300 11.48 ie fpr oeile Pere ON fd oe 0.55 0.00330 11.52 Bee se rere Oeras ik cicae oe 0.50 0.00350 11.54 eae meee 4 sate D.Gweak, pee ¥, 0.47 0.00376 11.58 Sats i ae pane O.GRh ae Sues 0.45 0.00405 11.61 ya tats TOit : csntte oes 0.42 0.00420 11.62 aes Baise fee 2O ees ae te 0.30 0.00600 11.78 sack eee gates
Effect of Added Salts.
The figures given in the tables are for pure solutions of the acids or bases. The addition of sodium chloride, or other neutral chlorides, tends to increase the hydrogen-ion concentrations of acids 1% 14 15 16 and the hydroxide-ion concentration of bases.1* Neutral sulfates, on the other hand, tend to decrease the hydrogen-ion concentrations of acids. .
This contrasting effect of chlorides and sulfates on the hydrogenion concentrations of solutions of sulfuric and hydrochloric acids was shown by Thomas and Baldwin.*’ Their results for 0.1 normal acids are shown in Figs. 39 and 4o. In each case a solution of acid was
mixed with a solution of salt and diluted to 100 cubic centimeters so that the final concentration of acid was 0.1 normal and that of the salt — the concentration whose effect was being studied. The hydrogen-ion concentrations were measured, by means of the hydrogen electrode, two days after the solutions were made up.
But this is also the order of increasing degree of hydration, or the number of molecules of water combined with the individual cations at infinite dilution. Poma‘** found that chlorides increase the hydrogenion concentrations of hydrochloric acid solutions in the following order :
In extending the work of Thomas and Baldwin, Wilson ** pointed out that one of the remarkable features of their results is that when the logarithm of the concentration of hydrogen ion is plotted against the concentration of added salt, in the case of the alkali chlorides, the curves are apparently straight lines, of the general formula
m moles per liter of salt.
It was also shown that this equation is independent of the strength of the acid solution, the value for b depending only upon the kind of alkali chloride added. Curves showing the effect of adding sodium chloride to four different concentrations of sulfuric acid are shown in Fig. 41. Apparently the curves are not only straight lines, but all four have the same slope, the average value for b being 0.205.
mole per liter, which can be accounted for only on the assumption that more than three-quarters of the water present has ceased to play the role of solvent. The hydration theory assumes that this is brought about by the water combining with the salt.
If the rise in hydrogen-ion concentration is due to the removal of water by the added sodium chloride, it should be possible to determine the degree of hydration of the salt at any concentration from hydrogen-ion measurements. Assuming this to be so, we should reason as follows: From the above equation, log([H*]/a) = bm. But [H"]/a is the factor by which the acid concentration has been multiplied by adding m moles per liter of salt. Let w represent the total number of moles of water, free or combined with salt, in 1 liter of solution containing m moles of salt. The moles of free water then equal wa/[H"] and the moles of water combined with one mole of salt equal (w/m) X (1—a/[H’]). Calling this latter value h, we have
The calculated number of molecules of water combined with one molecule of sodium chloride at infinite dilution would thus be 128 x 0.205 or 20.2, which is in striking agreement with the value 26.5 obtained by Smith ** from a very different type of measurement. Calculations of the degrees of hydration at infinite dilution of the chlorides of potassium, ammonium, and lithium made from the equation h = 128b also agreed fairly well with Smith’s corresponding values.
A means is thus afforded to calculate the change of pH value that will be produced by the addition of a neutral chloride to an acid solution. Let I represent the pH value of the acid solution containing no salt, which may be found in the preceding tables. Let F be the pH value after the addition of m moles per liter of salt and H he the number of molecules of water combined with one molecule of salt at infinite dilution. Then
The use of this equation does not depend upon the validity of the theory. The measurements of Thomas and Baldwin show that it may be used for the addition of chlorides to sulfuric and hydrochloric acids by substituting the following values for H:
barium chloride 50
The effect of adding sulfates cannot, however, be attributed to hydration, since they decrease the hydrogen-i ion concentrations of acid solutions. Their action is probably due to the formation of addition compounds complicated by hydration effects. For the hydrogen-ion concentrations of sulfuric and hydrochloric acid solutions containing neutral sulfates, reference should be made to the original papers of Thomas and Baldwin.
A skin is subjected to liquors of widely different pH value in passing through the tannery. From a lime liquor having a pH value of 12.5 it may pass into a bate liquor with a pH value of 7.5, then into a pickle liquor of pH —1.5, then into a chrome liquor whose pH value is rising from 3 to 4, and then into a fat liquor at pH = 9. Or, in vegetable tanning, the skin may pass from the bate liquor to a tan liquor whose pH value may be anything from 2.5 to 5.5, depending upon the method of operation of the yards. But in spite of the wide variation in pH value to which the skin is subjected in passing through the tannery, the processes are all sensitive to comparatively small variations in pH value unless each variation is compensated by corresponding changes in the process itself. »
Physical Chemistry of the Proteins.
The physical chemistry of the proteins is one of the foundations upon which leather chemistry is built, but until comparatively recently our knowledge of the chemical reactions of the proteins was hardly sufficient to permit of quantitative treatment. Proteins did not seem to show the stoichiometric relations of orthodox physical chemistry to earlier investigators because they failed to recognize the full number of phases existing in a given system and the necessity for making measurements at definite hydrogen-ion concentrations. )
The way for the quantitative development of the physical chemistry of the proteins was paved by the appearance of Donnan’s theory of membrane equilibria, which was applied by Procter? to the swelling of gelatin and further developed by Procter and Wilson * into a quantitative theory of the swelling of protein jellies. In an extensive series of researches, Loeb * has extended this work to include also the osmotic pressure, viscosity, stability, and electrical potential differences of protein systems as well as a general theory of colloidal behavior. This valuable work is now available in book form® and should be consulted as having an important bearing upon leather chemistry.
It will be shown in this chapter that proteins conform to the classical laws of physical chemistry and that their reactions are indicated by. well established principles. Donnan’s theory forms the logical starting point for this presentation. A good discussion of Donnan’s theory is given in Lewis’ Physical Chemistry ;* we have extended it in this chapter to a consideration of the effects of valency.
This theory deals with the equilibria resulting from the separation by a membrane of two solutions, one of which contains an ionogen having one ion that cannot diffuse through the membrane, which is permeable to all other ions of the system. As an example, Donnan
takes an aqueous solution of a salt NaR, such as Congo red, in contact with a membrane which is impermeable to the anion R’ and the nonionized salt, but will allow Na* or any other ion to pass freely through it. The membrane separates the Congo red solution from an aqueous solution of sodium chloride, which will diffuse from its Solution II into the Solution I of NaR. When equilibrium is established, if a small virtual change is made reversibly at constant temperature and volume, the free energy will remain unchanged; that is, no work will ‘be done. The change here considered is the transfer of dn moles of Na* and Cl’ from II to I. The work, which equals zero, is
This equation of products, simple though it may appear, is of such fundamental importance in the quantitative development of leather chemistry that any doubt as to its validity should be dispelled at the outset. The derivation of the equation need not involve the use of thermodynamics, since it can readily be visualized. In passing from one phase to the other, the oppositely charged ions must move in pairs, since they would otherwise set up powerful electrostatic forces that would prevent their free diffusion. For this reason a sodium or a chlorine ion striking the membrane alone could not pass through it. But, since the membrane is freely permeable to both Na* and Cl’, when two oppositely charged ions strike the membrane together, there 1s nothing to prevent them from passing through into the solution on the opposite side. The rate of transfer of these ions from one solution to the other depends, therefore, upon the frequency with which they chance to strike the membrane in pairs, which is measured by the product of their concentrations. At equilibrium the rate of transfer of Na* and Cl’ from Solution II to Solution I exactly equals the rate of transfer of these ions from Solution I to Solution II, from which it follows that the product of the concentrations of these ions has the same value in both solutions.
It is interesting now to note the effect of complicating the system by the introduction of another salt, such as KBr. Following the same line of reasoning, it will be evident that equilibrium will be established only when the product [K*] X [Br’] has the same value in both solutions, and the same is true for the products [K*] & [Cl’] and [Nat] X [Br’]. In fact, with any number of mono-monovalent. ionogens present in the system, the product of the concentrations of any _pair of diffusible and oppositely charged ions will have the same value in both solutions.
of products but very little more complicated. When a polyvalent ion strikes the membrane, it will pass through only when an equivalent » number of ions of opposite sign strike the membrane at the same time and pass through with it. The rate of transfer of any dissociated ionogen from one solution to the other is evidently determined by the product of all the ions required to produce the undissociated ionogen. At equilibrium, this product will have the same value in both solutions. It, for example, the system contained the ions Nat and SO”,, then the product [Na*] X [Na*] x [SO”,], or [Nat]? x [SO”,], would have the same value on both sides of the membrane, at equilibrium. The impermeability of the membrane to the anion R’ causes an unequal distribution of ions between the two solutions. In Solution II of the simple system including only the ionogens NaR and NaCl, let
But here we have the product of equals equated to the product of unequals, from which it is apparent, mathematically, that the sum of the unequals is greater than the sum of the equals, or that
The reasoning thus indicates that the concentration of diffusible ions in Solution I, at equilibrium, is greater than in Solution II, and this has been shown to be true in numerous experiments. If we let the excess of diffusible ions of Solution I over Solution II be repre-
which shows us further that + is greater than y or that the concentration of ionized sodium chloride is greater in Solution II than in Solution I. The added sodium chloride does not distribute itself equally throughout both solutions, but, at equilibrium, it is the more concentrated in Solution II. : | |
The different distribution of ions in the solutions at equilibrium gives rise, not only to a difference in osmotic pressure, but also to an electrical difference of potential across the membrane. Donnan derived the equation for this potential difference by the following thermodynamic reasoning. :
tremely small quantity Fdn of positive electricity be transferred isOthermally from II to I. In this virtual change of the system from equilibrium, the following work terms must be considered: the change in free electrical energy represented by Fdn (ayy — 1) and the simultaneous transfer of pdn moles of Na* from II to I and of qdu moles of Cl’ from I to II, where p and q are the respective transport numbers of the ions, and hence p+q=1. The maximum osmotic work of operation of this transfer of ions is represented by the expression
mechanism of many reactions involved in leather making.
It will now be shown that this equation is still valid when other ions of any valency are added to the system. Consider the general case where an ionogen yielding the ion M** of valency a is added. By applying the above line of reasoning to the potential difference produced by the unequal distribution of the ions of the added ionogen between solutions I and II, we arrive at the equation
At equilibrium, the unequal distribution of the added ionogen between solutions I and II produces exactly the same potential difference as the unequal distribution of sodium chloride. Although the addition of any ionogen must produce a change in the measured potential difference, by disturbing the equilibrium, all ionogens present when equilibrium is again established are producing the same potential difference, regardless of valency. The potential difference can thus be calculated from the determination of the distribution of only one kind of ion between the two solutions.
The complexity of systems, such as those just described, is due to the fact that the membrane prevents the diffusion of one kind of ion from one phase to the other. A similar set of conditions is brought about whenever one of a number of ions of a system is prevented from diffusing from one phase to another, which is true for every basic tannery process. When skin protein is brought into equilibrium with various tannery liquors, the diffusion of the protein ions is prevented, not by a membrane, but by their own forces of cohesion. This will be made clear in discussing the swelling of proteins.
Swelling of Protein Jellies.
When a strip of dry gelatin is soaked in water, it swells by absorbing water, increasing in volume from 5 to Io times, depending upon the temperature of the water and the quality of the gelatin. With increasing concentration of acid, or alkali, the swelling increases to a maximum and then decreases. The property of swelling in aqueous solutions appears to be common to all proteins under conditions such that they do not pass directly into solution. The swelling caused by acids and alkalies is generally counteracted by the addition of neutral salt or by increasing the concentration of acid or alkali sufficiently.
While attempting to arrive at a rational explanation of the molecular mechanism of tanning, Procter was continually confronted by the necessity of first explaining the mechanism of swelling and to him belongs the credit of being the first to recognize the almost complete dependence of the science of leather chemistry upon the theory of swelling. In 1897 he started an investigation? of the swelling of gelatin in solutions of acids and salts which has culminated in the Procter-Wilson theory of swelling.
Procter’s general method of experimentation was as follows: Sheets of thin, purified bone gelatin were cut into portions containing exactly I gram each of dry gelatin. A portion was put into each of a series of stoppered bottles containing 100 cubic centimeters of hydrochloric acid of definite concentration. A fter 48 hours, which was shown to be sufficient for the attainment of practical equilibrium, the remaining solution was drained off and titrated with standard alkali. The gelatin plates were quickly weighed and the volume of solution absorbed was calculated from the increase in weight of the plates. The swollen
gelatin was then put back into the bottles and covered with enough dry sodium chloride to saturate the solution which had been absorbed by the gelatin. This caused the gelatin to contract and give up the absorbed solution. After 24 hours, when equilibrium was again established, the solution expelled by the salt was drained off and titrated to determine the amount of free acid which had been absorbed by the gelatin. A small amount, usually about 1 cubic centimeter, of solution always remained unexpelled by the salt and, although not strictly true, this was assumed to have the same concentration of free acid as the portion expelled, due allowance being made for the increase in volume of solution due to saturating it with salt. The acid still unaccounted for was assumed to be combined with the gelatin base. i
A further set of checks was obtained by dissolving the gelatin, dehydrated by treatment with salt, in warm water and titrating with standard alkali, using both methyl orange and phenolphthalein, the former indicating the free acid left in the jelly and the latter the total, including the acid combined with the gelatin base, which was obtained by difference.
Experimental values for the volume of solution absorbed by the gelatin, the free acid left in the external solution, the free acid in the jelly, and the acid combined with the gelatin base are shown in Table XI and in Figs. 42 and 43. These were taken from the table on page 317 of Procter’s paper, The Equilibrium of Dilute Hydrochloric Acid and Gelatin. In plotting the results, the concentration of gelatin chloride is taken as the difference between the concentrations of total chloride and free HCl in the jelly. The calculated values given along with the experimental ones will be discussed later in connection with the theory.
Procter recognized that gelatin combines with HCI forming a highly ionizable chloride and that the resulting equilibrium is a special case of the membrane equilibria described by Donnan. Instead of tracing the development of the theory of swelling from Procter’s earliest work to its present status, it will simplify matters to present the theory from the deductive reasoning furnished later by Wilson and Wilson.® They set out to prove that the entire equilibria can be determined quantitatively from the orthodox laws of physical chemistry on the simple assumption that gelatin, or any protein, combines with hydrochloric acid to form a highly ionizable chloride. It seemed that success in this would furnish substantial proof of the correctness of the theory.
In order to make the reasoning general, let us consider the hypothetical protein G, which is a jelly insoluble in water, is completely permeable to water and all dissolved ionogens considered, is elastic and under all conditions under consideration follows Hooke’s law, and com-
Now take one millimole of G and immerse it in an aqueous solution of HA. The solution penetrates G, which thereupon combines with some of the hydrogen ions, removing them from solution, and consequently the solution within the jelly will have a greater concentration of A’ than of H*, while in the external solution [H*] is necessarily equal to [A’]. The solution thus becomes separated into two phases, that within and that surrounding the jelly, and the ions of one phase must finally reach equilibrium with those of the other phase.
It is apparent from Donnan’s line of reasoning, given earlier in the chapter, that the product [H*] * [A’] will have the same value in the external solution as in the jelly phase at equilibrium, or that
where e is defined as the excess of concentration of diffusible ions of the jelly phase over that of the external solution. Where any two variables are known, all others can be calculated, for from equations (2) and (3) we get the following:
Since [A’] is greater in the jelly than in the surrounding solution, the negative ions of the colloid compound will tend to diffuse outward into the external solution, but this they cannot do without dragging their protein cations with them. On the other hand, the cohesive forces of the elastic jelly will resist this outward pull, the quantitative measure of which is e, and according to Hooke’s law
where the only variables are V and y.
If the molecules or atoms of the protein are not themselves permeable to all ions considered, the quantity a@ should not be taken as the whole of the initial volume of the jelly, but only as the free space within the original, dry jelly through which ions can pass. For our hypothetical protein, then, we shall consider the limiting case where the value of a is zero. This assumption in the case of gelatin introduces errors less than the probable experimental error because of the relatively large values for V over the significant swelling range. [quation (12) thus reduces to
Knowing the values of the constants, K and C, we can plot the entire equilibrium as a function of any one variable. Procter and Wilson *® obtained the value K = 0.00015 for the sample of gelatin used in their experiments by adding successive portions of standard HCl to a dilute solution of the gelatin and noting the corresponding rises in hydrogen-ion concentration. The difference between the concentration of hydrogen ion that would have been. found upon adding the acid to pure water and that actually found by adding it to the same
volume of gelatin solution was taken as the amount of acid combined with the gelatin, or as the value of [GH'*] in equation (1). Substituting any two sets of determinations of [GH*] and [H*] in equation (1) and solving the resulting equations simultaneously, the value of “ can be found.
equation (8). It was found to vary with the temperature and with the quality of the gelatin, but had the value 0.0003 for the sample of gelatin used by Procter and at the temperature of his experiments, 18° C,
In order to compare calculated values for V with experimental determinations of the increase in volume of I gram of gelatin, it is necessary to know its equivalent weight. Procter originally regarded gelatin as a diacid base with a molecular weight of 839, but later work by Procter and Wilson showed that it should rather be regarded as acting as a monacid base, with an equivalent weight of 768, in acid solutions not sufficiently concentrated to cause decomposition. 768
grams of gelatin combine with a limiting value of 1 mole of hydrochloric acid and the combination resembles that of HCl with a weak monacid base. For this reason we may use the value 768 as the equivalent weight of gelatin. As for the molecular weight of gelatin, no convincing figures have yet been produced and it may be questioned whether
function of the concentration of hydrochloric acid.
they would have any real value, if obtained. We look upon a plate of gelatin as a continuous network of chains of amino acids, there being no individual molecules, unless one wishes to look upon the plate of gelatin as one huge molecule.
From equation (13) and the values of the constants given above, Wilson and Wilson calculated all of the variables of the equilibrium for gelatin and hydrochloric acid over the range covered by Procter’s
The agreement between calculated and observed values is absolute, within the limits of experimental error. For this reason Procter and Wilson regard their theory as proved, but, if further corroboration is desired, it can be found in the extensive researches of Loeb, some of which will be described later. Jt is worthy of note that no other theory of swelling has yet passed the stage of qualitative speculation.
Cc. solution
absorbed by I g. [ Total chloride} [HCl] V gelatin [HC1] in jelly in jelly Initial in Calcu- Calcu- Ob- Calcu- Ob- Calcu- Ob[HCI] soln. lated lated served lated served lated served
0.006 0.0011 o35 43.4 44.1 0.0001 0.0005 0.012 0.014 0.008 0.0018 37.5 48.8 48.7 0.0002 0.0004 0.014 0.015 0.010 0.0025 41.7 54.3 59.9 0.0004 0.0004 0.016 0.015 0.010 0.0028 42.7 55.60 58.4 0.0004 0.0004 0.017 0.015 0.010 0.0032 43.2 56.2 53-7 0.0005 0.0005 0.019 0.017
0.015 0.0073 40.8 53.1 57-9 0.002 0.002 0.024 0.020 0.015 0.0077 40.2 52.3 522 0.002 0.002 0.025 0.022 0.015 0.0120 37.5 48.8 51.9 0.005 0.006 0.031 0.027 0.020 0.0122 a4 48.6 4 Oy, 0.005 0.006 0.031 0.027
0.025 0.0170 34.5 44.0 40.4 0.008 0.009 0.036 0.037 0.025 0.0172 34.3 44.7 48.1 0.008 0.009 0.036 0.031 0.050 0.0406 20.7 34.8 36.4 0.026 0.030 0.063 0.061 0.050 0.0420 26.4 34.4 31.1 0.027 0.030 0.005 0.008 aie 0.0576 24.0 212 34.0 0.041 0.043 0.082 0.079 0.075 0.0666 23.0 29.9 27.9 0.049 0.050 0.092 0.095 0.075 0.0680 22.8 29.7 29.1 0.050 0.053 0.0904 0.092 0.100 0.0930 20.7 27.0 23.1 0.072 0.072 0.121 0.126 0.100 0.09044 20.5 26.7 26.4 0.073 * 0.072 0.122 0.121 ae 0.1052 19.8 25.8 29.8 0.083 0.085 0.134 0.128 0.125 0.1180 18.9 24.6 24.4 0.095 0.090 0.148 0.148 0.150 0.1434 17.9 233 24.0 0.118 0.118 0.174 0.173 0.150 0.1435 17.9 23-3 24.2 0.118 0.118 0.174 0.172
0.175 0.1685 17,3 22.2 23.5 0.141 0.138 0.200 0.200 0.200 0.1925 16.3 21-2 20.6 0.164 0.161 0.225 0.229 0.200 0.1940 16.2 alak 227 0.166 0.165 0.227 0.225 0.200 0.1945 16.2 2I.1 22.1 0.167 0.164 0.228 0.226 0.250 0.2450 15.1 10.7 20.2 0.213 0.210 0.279 0.281 0.300 0.2950 14.0 18.2 20.0 0.261 0.260 0.332 0.332
Other proteins which do not dissolve in cold water behave much like gelatin in respect to swelling, although they apparently have different values for the constants, K and C, as well as for equivalent weight. It is interesting to reason from the theory what differences in swelling would result from changes in the values of the constants. Since V = e/C, an increase in the value of C means a corresponding decrease in the degree of swelling. The effect of a change in the value of K, the hydrolysis constant of the protein, is shown in Fig. 44 for a fixed value of C. At K=o, the point of maximum swelling occurs at
x =o and has the value 1/7/C. As K increases in value, the point of maximum swelling decreases in value and occurs at increasing values for +. At K= oo, the point of maximum has the value zero and occurs at 7 = oo
but different values for the hydrolysis constant.
tration, under constant conditions, provided the gelatin salts formed are ionized to the same extent. It was generally thought that different monobasic acids produce different degrees of swelling, following the order of the well-known Hofmeister series of the ions, until Loeb pointed out that the earlier investigators, through failure to measure the hydrogen-ion concentration, had fallen into the error of attributing to the several acids effects caused merely by differences in hydrogen-ion concentration. He found, at a fixed value for x, that practically the same degree of swelling is produced by all monobasic acids, as well as
as monobasic.
The calculation of the degree of swelling of proteins in solutions of polybasic acids is not quite so simple as for monobasic acids. Suppose | that G were to combine with the hydrogen ion but not the anion of the polybasic acid H,A. Letting x represent the concentration of the polyvalent anion in the external solution at equilibrium, zg the concentration of the anion of the.gelatin salt, and y + zg the total concentration of anion in the jelly, it is evident from the reasoning given above that
The total concentration of diffusible ions is greater in the jelly than in the external solution by the amount e and swelling in degree directly proportional to e will result. It can readily be seen that as x increases from zero, without limit, e and the degree of swelling increase to a maximum and then decrease, approaching zero, for z has a limiting value since it cannot exceed the total concentration of gelatin. At 4 =0, y=0, ande=o. As ~# increases without limit our equations approach the limiting relations
The extent of swelling by polybasic acids which combine as such with the protein will be considerably less than that caused by monobasic acids, as Loeb has shown, because fewer anions will be associated with equivalent weights of the protein. For example, for equivalent weights of gelatin sulfate and gelatin chloride, there would be only half as many sulfate ions as chloride ions. For very small values of +, we should therefore expect sulfuric acid to produce only half as much swelling as hydrochloric acid at the same hydrogen-ion concentration and this is actually the case.
Repression of Swelling by Salts.
The theory accounts quantitatively for the action of neutral salts in repressing the swelling of proteins by acid. In the system described above in which the protein G was immersed in a solution of HA, consider the addition of the mono-monovalent salt MN, neither of whose ions combine with G. At equilibrium, let the concentration of M* be represented by u in the external solution and by v in the jelly. It is evident from the general equation of products that the product
Now, if the value of x» -+ u increases while remains constant, the value of e, and consequently the swelling, will decrease. The addition of MN to the system increases u and hence must cause a decrease in the degree of swelling, since it increases z only by causing a diminution of the volume of the jelly.
It is important to recognize that the repression of swelling by salts does not depend upon any repression of ionization of the protein salt. The salt acts so as to lower the value of e, which is the measure of the force producing swelling. In some cases, the ionization may be repressed to some extent and this would assist in repressing the swelling, but in the case of gelatin chloride, the swelling is markedly reduced long before there is any repression of ionization of gelatin chloride measurable by means of calomel electrodes.
Proteins are amphoteric substances, reacting both as weak acids and as weak bases. In this respect, they retain the properties of the amino acids from which they are formed. Hydrated aminoacetic acid is capable of assuming either a positive or negative charge, or both, by ionizing as acid or base, or both, thus:
But this is essentially the same as equation (1) except for the fact that [H*] is replaced by [OH’]. It is thus apparent that proteins will behave in solutions of increasing concentration of alkali much as they do in solutions of acids so long as they undergo no chemical changes other than that of salt formation. Actually gelatin swells in alkaline solution to a maximum at a concentration of about 0.004 mole of hydroxide ion per liter, above which the swelling diminishes.
mole of hydrogen ion per liter.
The effect of valency is similar in both acid and alkaline solutions. Loeb found that the diacid bases calcium hydroxide and barium hydroxide give points of maximum swelling for gelatin only half as great as the monacid bases. For a given pH value, the amount of swell-
Seriim sal bimiwyr sey c.me eae eee ee See 47 6 perim globulin >A oes. 25. st cae ee eee ee 5.4 2 Eee albumen «then)ofic: 22). cee ae 4.8 7 Denatured :serum albumin, 3s... See 5.4 6 Oxybemoriobing ius. 3042 wos eee eee 6.7 9 Carbon monoxide hemoglobin................ 6.8 10 Reduced (hemoglobin 2.5.05 tu. s cee ee 6.8 10 Stroma globulins of blood corpuscles......... 5.0 8,9 Reds blood cellsncas si iene oe eee 4.6 iL Yeast extract proteins, (globulin). ............ 4.6 14 Csliaclin, «Ut uae tetas aaa en ee 9.2 2 Edestin ae cckos ON pet tes ee 5.6 15 Juberin >» (potata) fa, 2s can gue see ee eee approx. 4.0 12 Carrot. protein)... seen ee ee A 4.0 12 Lomato protein’ a; Soy tok ee ee ee % 5.0 12 Nuacleiccacidii, S55 come e cs io eee ae a ie 2.0 13
the protein ions rather than by the specific nature of the ions themselves.
In alkaline solution the protein ion is negatively charged, while it is positively charged in acid solution. In a solution, originally alkaline, in which the hydrogen-ion concentration is gradually increased, there must be some point at which the protein becomes electrically neutral ; that is, where it has an equivalent number of positive and negative charges. The hydrogen-ion concentration at which this occurs has
been called by Hardy! the isoelectric point of the protein. The isoelectric point of gelatin was found by Michaelis and Grineff 12 to lie at a pH value of 4.7 and this value has been repeatedly confirmed by Loeb and others.
Thomas and Kelly ** determined the isoelectric point of collagen, or rather hide powder, by means of acid and basic dyes. Portions of hide powder were first wet with solutions of different pH values, then with solutions of basic fuchsin or Martius yellow, and finally washed with solutions having the same pH values as were used to wet the portions initially. The fuchsin left the hide powder deeply stained only at pH values greater than 5 and the Martius yellow only at values below 5, indicating pH = 5 as the isoelectric point of collagen.
Porter ** observed that a point of minimum swelling of hide powder occurs at a pH value of 4.8, indicating this as its isoelectric point. Porter also found points of maximum swelling of hide powder at pH values of 2.4 in acid solution and about 12.3 in alkaline solution.
Two Forms of Collagen and Gelatin.
Quantitative experiments upon alkaline swelling are rendered difficult by the tendency for: the gelatin to pass into solution, which is very much more marked than for acid swollen gelatin. That gelatin and some other proteins undergo a change of form in alkaline solutions is apparent from recent experimental data. Lloyd ** observed a rather significant change occurring in gelatin dissolved in alkaline solution. A comparison between gelatin dissolved in acid solution and gelatin dissolved in alkaline solution was made as follows.
Two grams of gelatin were put into a flask containing 200 cubic centimeters of tenth-molar hydrochloric acid. After 6 days at 20° C., the gelatin was completely dissolved and 20 cubic centimeters of molar sodium hydroxide were added to the solution, which was then tested and found to be neutral to litmus. 220 cubic centimeters of saturated ammonium sulfate solution were then added and a white, flocculent precipitate formed, which was filtered off. The filtrate was tested and found to be free from protein. The precipitate was insoluble in cold water and was washed several times. It was dissolved in 2 cubic centimeters of hot water and set to a jelly upon cooling. A control experiment made by dissolving 2 grams of gelatin in 220 cubic centimeters of water with 1.12 grams of sodium chloride behaved in a similar manner.
For comparison, 2 grams of gelatin were put into a flask containing 200 cubic centimeters of tenth-molar sodium hydroxide. The gelatin was completely dissolved after 2 days at 20°C. 20 cubic centimeters of molar hydrochloric acid were then added to the solution, after which it reacted neutral to litmus. 220 cubic centimeters of saturated ammonium sulfate solution were added and a white, flocculent precipitate formed, which was filtered off. The filtrate, as in the
12.00 F105 10.73
previous experiment, was found to be free from protein. But the precipitate dissolved completely and rapidly in a small volume of cold water and would not set to a jelly even when the volume was reduced to 2 cubic centimeters.
Lloyd suggested that gelatin changes from a keto-form to an enolform in alkaline solution. The gelatin recovered from acid solution and which had the power of setting to a jelly would thus be regarded as the keto-form of gelatin, while that recovered from alkaline solution and which had lost the power of setting to a jelly would be looked upon as the enol-form of gelatin. Miss Lloyd regarded the change in alkaline solution as irreversible, but her experiments do not
show this. Mr. Kern, in the author’s laboratory, added hydrochloric acid to gelatin dissolved in a hot solution of sodium hydroxide until the pH value, as determined by the hydrogen electrode, was reduced to 4.7 and then allowed the solution to cool, whereupon it set to a firm jelly, indicating that the change is reversible. Miss Lloyd’s ex-
periment showed merely that it is not readily reversed by the addition only of the quantity of hydrochloric acid equivalent to that of the sodium hydroxide originally employed.
In studying the degree of plumping of calf skin as a function of pH value, Wilson and Gallun found two points of minimum, one at 5.1 and the other at 7.6. This work will be described in Chapter 9. Wilson and Kern 7° followed this with a series of experiments upon the swelling of gelatin in buffer solutions and also found two points of
A series of buffer solutions was prepared, each member of which had a final concentration of tenth-molar phosphoric acid plus the amount of sodium hydroxide required to give the desired pH value as determined by the hydrogen electrode at 20° C. The pH values ranged from 3 to 12. 200 cubic centimeters of each solution were put into a stoppered bottle and kept in a thermostat refrigerator at 7° C. After the temperature of each solution had reached 7°, a small strip of high grade gelatin of known weight was put into it. All strips were taken as nearly alike as possible and were kept in the solutions at ee for 4 days, after which each strip was quickly blotted off and weighed. The results were carefully rechecked. In Table XIII are given the gain in weight per gram of dry gelatin and the initial’ and final pH values of the buffer solutions. Fig. 45 represents the degree of swelling as a function of the pH value.
Wilson and Kern suggested that the two points of minimum represent the isoelectric points of the two forms of gelatin described by Lloyd and this view appears to be substantiated by other data available in the literature.
Experiments upon the mutarotation of gelatin led Smith 17 to suggest that gelatin exists in two forms: a sol form, having a specific rotation of [a]p =— 141 and being stable at temperatures above 36° 455 and a gel form, with a specific rotation of [a]p = — 313 and stable under 15°, a condition of equilibrium existing between the two forms at intermediate temperatures. The gel form is characterized by its power to set to a jelly, which is lacking in the sol form. Smith calculated that a concentration of from 0.6 to 1.0 gram of the gel form per 100 cubic centimeters is required to produce gelation. As the temperature is increased above 15°, the total concentration of gelatin required to produce gelation is increased because of the decreasing proportion of the gel form, which does not exist at all above et Gelatin is the only protein known to show mutarotation, but it gradually loses this property along with its jellying power, when its solutions are kept at temperatures above 70° C.
Davis and Oakes #* measured the viscosities of a series of solutions of gelatin at 40° C. at different pH values. Their results are shown jn Fig. 46. A point of minimum occurs at 8, but none at 4.7, the isoelectric point of gelatin as determined by Loeb. They commented upon this as follows: “There may be considerable difficulty in reconciling this minimum viscosity at pH about 8 with the isoelectric point at pH 4.7.” But Davis and Oakes really measured the point of minimum viscosity of the sol form, since their determinations were made at 40° C., whereas Loeb determined the isoelectric point of the gel form.
Another case of the apparent disappearance of an isoelectric point when working at a temperature of 40° C. is to be found in the work of Wilson and Daub,!® who experimented upon the bating of calf skin at
* Further Studies of the Physical Characteristics of Gelatin Solutions. C. E. Davis and Er: Oakes. _J. Am, Chem. Soc. 44 (1922), 464. : ae Critical Study of Bating. J. A. Wilson and G. Daub. J, Ind. Eng. Chem. 13 1921), 1137.
40° at different pH values. They observed that a point of minimum plumping occurred in the region of pH = 8, but not at pH = 5, the isoelectric point of collagen found by Thomas and Kelly and by Porter. But Wilson and Gallun observed points of minimum plumping of calf skin at both 5 and 8, when working at low temperatures. The recent work of Sheppard, Sweet and Benedict 2° adds further evidence of the existence of critical pH values at both 5 and 8. They obtained a
with change of pH value.
curve for the rigidity of gelatin jelly as a function of pH value exhibiting a shoulder at 5 and a flattish maximum between 7 and 9. Apparently the change in gelatin from the gel form to what has been called the sol form takes place both with rise of temperature and with rise of pH value. Since the experiments of Wilson and Kern were performed at 7° C., they were dealing with the gel form of gelatin
in acid solution and actually observed a point of minimum at pH = 4.7, the isoelectric point of the gel form. The appearance of a second point of minimum swelling at pH = 7.7 seems to indicate that between 4.7 and 7.7 the gelatin passes from the gel to the sol form and that the second point of minimum occurs at the isoelectric point of the sol form. It was only by working at temperatures as low as 7° that they were able to prevent the gelatin from passing into solution at the higher pH values.
While objection may be raised to the terms gel and sol form as applied to the two forms of gelatin and of collagen, they will serve as well as any until more is known of the transition. Lloyd’s suggestion that the change is a keto-enol tautomerism is. still speculative.
Parker Higley,*! at the University of Wisconsin, has recently investigated the absorption spectra of gelatin dispersions of different pH value and plotted a series of curves, at several densities, for the wave length of maximum absorption in the ultra violet as a function of pH value. The curves all show two points of minimum, one at pH = 4.68 and the other at 7.66, coinciding with the points of minimum swelling _ of gelatin. That the two points of minimum have a real existence is thus strikingly confirmed from an unexpected source.
It is apparent from the discussion of Donnan’s theory of membrane equilibria that the unequal distribution of ions between a jelly and its surrounding solution must give rise to an electrical difference of potential between these two phases whose measure is (RT/F) .log(x/y), where x is the hydrogen-ion concentration of the external solution and y that of the solution within the jelly and this value holds true regardless of the valence or number of ions in the system. The potential difference can therefore be calculated from the determinations of pH value in the jelly and in the external solution. Changing from natural to common logarithms and substituting the numerical value for RT/F at 20° C., we get.
supposed to be at equilibrium.
In a typical experiment,?* 1 gram of purified gelatin, powdered to a grain size between 30 and 60 mesh, was put into each of a series of solutions of different concentrations of hydrochloric acid or sodium
tin jelly and the surrounding solution.
hydroxide. The volume of each solution was 350 cubic centimeters and the temperature 20° C. After 4 hours the volume occupied by each portion of gelatin was measured, the solution filtered off, and the gelatin melted so that the pH values of both jelly and solution could be determined by means of the hydrogen electrode. The gelatin was then allowed to set to a jelly in the receptacle illustrated in Fig. 47 and the potential difference between the jelly and external solution was then measured with a Compton electrometer. The results of such a series are shown in Table XIV along with calculations of the potential differences made from the pH determinations. The calculated and observed results are at least of the same sign and order of magnitude, which is a good agreement considering the nature of the experiments and the dilutions of the solutions. It will be shown later that the method is capable of very much better agreement where the complications involved in melting and resetting of the jelly are avoided, as in the measurement of potential difference between a solution of gelatin and a protein-free solution with which it is in equilibrium and from which it is separated by a semi-permeable membrane, especially where the solutions have greater conductivities.
According to the theory, the concentration of free acid in an acidswollen jelly should be less than that in the external solution and, likewise, the concentration of free alkali in an alkali-swollen jelly should be less than that in the external solution with which it is in equilibrium.
O.0OLONGE Cl -- wues ees 28 4.44 235 + 1.09 + 63.0 + 56.0 D.00OSN PE Clas nates 20 4.56 3.55 + 1.01 + 58.6 Ache O.0000N EiGl ewes eae 18 4.79 3.0245 Oe + 51.0 + 26.5 O:000IN SHES. a eae 16 4.85 4.24 + 0.61 + 36.0 + 15.0 Wekett uaGctnet ese coleanas 17 4.89 4.97 — 0.08 — 4.5 — 17.5 O.000IN- Na@H Wor... 18 4.98 5.96 — 0.98 — 57.0 — 59.0 0,.0002N"= NaOH... ...ci5 9 28 5.06 6.24 —1.18 —680 — 61.0 0.0005N NaOH 7.4 50.2.4. 537 5.50 6.46 — 0.96 — 56.0 — 70.0 COOION NaOHus.. 3. ss d0 6.74 7.30 — 0.56 — 33.0 — 66.0 0.0020N NaOH) 2225... .. 47 0.54 10.56 —1.02 —59.0 —46.0 0.0040N NaOH ......... 48 10.15 11.08 — 0.93 — 48.0 — 36.0
This is verified by the figures in Table XIV, which show, for pH values of the external solution less than 4.7, that the hydrogen-ion concentration is greater in the solution than in the jelly, while for pH values of the external solution greater than 4.7, the hydrogen-ion concentration is less or the hydroxide-ion concentration greater in the solution than in the jelly.
Sheppard and Elliott 24 made a study of the causes of the reticulation of the surfaces of photographic negatives that has a bearing upon a similar kind of trouble sometimes occurring in the vegetable tanning of skins. During the fixing or washing of a negative, the wet gelatin layer sometimes becomes more or less finely wrinkled or corrugated, the network of puckers forming a pattern extending either over the whole of the negative or only over part of it. They found that this reticulation can be produced by the combined action of a swelling agent and a tanning agent.
Fig. 48 represents a print from a negative treated to produce reticulation by Mr. Daub in the author’s laboratories. The plate was flashed, — developed, fixed with sodium thiosulfate, washed, and then immersed in a solution of wattle bark extract containing 5 grams of tannin and 0.2 mole of acetic acid per liter; the temperature was kept at
28°C. After several minutes the gelatin surface began to pucker at isolated points and this action gradually spread over the entire surface, producing series of ridges of swollen gelatin with valleys of hardened and contracted gelatin in between. Following this action, the silver particles migrated from the hardening portions into the swelling ridges, giving the negative the mosaic-like appearance shown in the print. Often the puckering became well pronounced before the
liken the effect to the production of Liesegang rings.
The acid tends to cause a swelling of the gelatin while the tannin tends to cause a hardening and contracting action. But the acid diffuses relatively very rapidly whereas the diffusion of the tannin is greatly retarded both by its high molecular weight and by its tendency to combine with the gelatin, forming a compound less permeable and having a much lower power of swelling than the original gelatin. The action becomes greatly accelerated as the temperature is raised towards the melting point of the gelatin jelly. When the action is prolonged
at higher temperatures, provided the jelly does not dissolve, a second and much coarser series of puckers begins to form, tending to mask the finer pattern. In the coarser pattern, the peaks of the ridges may be from one to several millimeters apart.
The reticulation of the surface of skin in tanning is a very serious matter as the pattern formed is permanent and materially reduces the selling value of the leather. The pattern formed on skins is usually of the coarser variety and would hardly pass as an artistic sample of embossing, which the photographic negative might do, because of the fineness of the pattern and distribution of silver particles. The reticulation of skin may attend the injudicious use of acid in attempting to plump the leather during tanning, or it may occur where acid-producing ferments get the upper hand in a yard where fresh liquors are normally used. The corrective is to prevent the swelling action, either by neutralization of the acid or by the addition of salt.
Structure of Gelatin Solutions and Jellies.
Procter’s *° investigations of the behavior of gelatin jellies led him to regard them as having a structure consisting of a network of molecules cohering to each other, but leaving interstices large enough to permit the passage of water and simple molecules and ions. The long chains of amino acids making up the protein molecules are peculiarly fitted to produce such a structure through combination of the acid and basic terminals of these chains. A hot solution of gelatin may be looked upon as a true solution consisting of individual gelatin molecules, or at least of comparatively small polymerized groups, but the molecules orientate themselves, as the solution cools, so as to leave a minimum of free energy, the most active acid groups tending to unite with the most active basic groups until a continuous network is formed throughout the system. A block of jelly might thus be looked upon as an enormous, single molecule. Such a view is not radical in the light of modern theories of crystal structure.
According to the Procter-Wilson theory of swelling, when a block of gelatin jelly is immersed in a solution of hydrochloric acid, the solution passes into the jelly, filling up the interstices. Of the ionized gelatin chloride, which then forms, the chloride ions remain in the solution in the interstices while their corresponding gelatin cations form part of the network and are not in solution in the same sense as the anions. In tending to diffuse into the outer solution, the anions exert a pull upon the cations forming part of the network, causing an increase in volume of the jelly proportional to the pull exerted, so long as the elastic limit is not exceeded. That gelatin jellies are truly elastic and follow Hooke’s law may be taken as proved chemically by the agreement between calculated and observed results shown in Table XI. More recently Sheppard and Sweet 28 proved by measure-
to the breaking point.
Loeb’s work on the viscosity of gelatin solutions, to be discussed presently, indicates that the initial step in gelation is the combination of individual molecules to form large aggregates, possibly in a manner similar to the growth of crystals. Bogue *’ pictures this process as the formation of catenary threads by the union of the individual molecules end to end. The manner in which fibrous curds of soap are formed led McBain ?® to a similar view regarding the structure of soap jellies and solutions. He attributes the elasticity of gels to the formation of an exceedingly fine filamentous structure. Innumerable molecules placed lengthwise and held together by forces of residual valence are assumed to make up these fine threads, which may be microns or millimeters in length.
Considering the nature and variety of the amino acids composing the gelatin molecule, as shown in Table I of Chapter 3, we should hardly expect the polymerization of gelatin to take place along a single line, but in every direction and probably with cross chains growing to support chains increasing in length in other directions. The increasing viscosity of gelatin solutions with time, upon cooling, would thus be attributed to the increasing size of the particles; the formation of a rigid jelly to the final union of the large particles, forming a structure continuous throughout the entire system.
There is an abundance of evidence to support Procter’s view of the structure of jellies and Loeb’s view that gelatin solutions, after standing for a time at temperatures below 35° C., always contain particles of jelly consisting of aggregates of gelatin molecules. A number of supporting lines of evidence are given in a review of the literature by Thompson.?®
Graham showed long ago that the velocity with which crystalloids diffuse through gelatin jellies is only very little less than the velocity through pure water. This slight reduction in velocity is in no way comparable with the apparently great physical difference in state between the jelly and water. Although the viscosity of a gelatin jelly is too great to be measured by the methods usually applied to liquids, simple molecules move through it as though in a medium of viscosity nearly that of water. The network theory explains this by assuming that the diffusing substance actually is moving through the pure water or aqueous solution in the interstices of the network. Any slight diminution in velocity can be accounted for by the small portion of any cross section of the jelly occupied by the gelatin network. The same holds true for gelatin solutions, the diffusing substance being able to pass through the particles of jelly in suspension almost as rapidly as through the solution surrounding the particles.
78 Colloid Chemistry of Soap. J. W. McBain. Brit. Assoc. Advancement Sci. Third Report on Colloid Chemistry (1920), 2. ( pies of Gelatin Solutions. F. C. Thompson. J. Soc. Leather Trades Chem. 3 T1919), 209.
Thompson shows from the work of Dumanski *° that the conductivity of a solution of potassium chloride in gelatin jelly is no less than in pure water when a correction is made for the small volume actually occupied by the gelatin network, whereas, if the apparent viscosity had any effect, the conductivity should be reduced by the gelatin to\a minute fraction of its value in pure water. |
The vapor pressure of even a 20-per cent gelatin jelly is practically the same as that of water, indicating the presence of pure water in accordance with the network theory.
By placing a strain upon gelatin jelly in one direction, double refraction is produced, a property always associated with a definite structure and with anisotropy. Even dilute solutions of gelatin show double refraction on compression or when passed between two cylinders rotating in opposite directions. With increasing strain, the effect is increased up to a point corresponding to an elastic limit. This indication of structure even in gelatin solutions corroborates the views of Loeb and of Bogue.
The fact that the viscosity of gelatin solutions is lowered by simply agitating the solution is another piece of evidence in favor of the existence of a structure in gelatin solutions and still further evidence is furnished by Loeb’s work on the viscosity of gelatin solutions and Bogue’s measurements of plasticity, to be described later.
tions to the Swelling of Gelatin Jellies.
In an extensive series of experiments, Loeb has shown that the variations in osmotic pressure and viscosity of gelatin solutions with change of pH value or of concentration of salt, parallel the corresponding variations in the degree of swelling of gelatin jellies, which is what would be expected on the basis of the theory of protein-salt formation described above. This parallelism is shown by the curves in Figs. 49 to 54.
In each determination *! of the two series of experiments performed to get the curves shown in Fig. 49, 1 gram of powdered gelatin was put for 1 hour at 20° C. into 100 cubic centimeters of acid solution of definite strength. The volume of the gelatin was measured, after settling, in a graduated cylinder and the pH value of the jelly was determined after melting. The volume is plotted against the pH value of the jelly and not that of the external solution, which was always lower, as explained in the discussion of the theory of swelling.
The curves in Fig. 50 were obtained by rapidly heating to 45° C. solutions of 0.8-per cent gelatin containing different amounts of acid, maintaining this temperature for 1 minute, cooling rapidly to 24°, and immediately determining the viscosity at 24°. The viscosity is plotted against the pH value of the gelatin solution.®2
In the experiments whose results are shown in Fig. 51, collodion bags, cast in the form of Erlenmeyer flasks having a volume of 50 cubic centimeters, were filled with I-per cent gelatin solutions containing different amounts of acid. Each bag was closed with a rubber stopper fitted with a glass tube serving as a manometer and put into
Variables as Functions of pH Value.
Fic. 49.—Volume of powdered gelatin. Fic. 50.—Viscosity of gelatin solution. Fic. 51—Osmotic pressure of gelatin solution.
a beaker containing dilute acid solution of the same kind as was used in making up the gelatin solution. When osmotic equilibrium was established, the level of solution in the manometer was recorded and plotted against the pH value of the gelatin solution.** The measurements were made at 24°.
the variation in each case is due to the same fundamental cause, namely, the establishment of a Donnan equilibrium. In the viscosity measurements, the solutions contain aggregates of gelatin molecules capable of swelling with change of pH value and, since the viscosity must increase with the increasing volume occupied by the gelatin, we should
Variables as Functions of Concentration of Added Salt.
Fic. 52.—Volume of powdered gelatin. Fic. 53.—Viscosity of gelatin suspension. ' Fic. 54.—Osmotic pressure of gelatin solution.
gelatin particles.
In the experiments on osmotic pressure, we have an application of the Donnan equilibrium which is considerably simpler than that involved in the swelling of jellies, although of a similar kind.
In the swelling and osmotic pressure experiments, we note that the points of maximum given by sulfuric acid are only half as great as those given by hydrochloric acid, which is in harmony with the theory, since the divalent sulfate ion has no greater diffusion pressure than
concentrations of gelatin salt.
In Figs. 52, 53, and 54 are given curves showing the depressing effect of increasing concentration of neutral salt upon the volume of powdered gelatin,** the viscosity of a suspension of powdered gelatin,** and the osmotic pressure of a solution of gelatin.*® Again we find a parallelism in the results that would be expected from the theory.
Osmotic Pressure and Membrane Potentials.
A discussion of the mechanism of the osmotic pressures exerted by protein solutions may serve to make the theory of swelling, which is the more important in leather chemistry, a little clearer. The collodion bags used in Loeb’s experiments were permeable to water and simple acids, bases, and salts, but not to dissolved proteins. Let us consider a solution of gelatin chloride and hydrochloric acid contained in a collodion bag which is brought into contact with pure water. Hydrochloric acid diffuses out through the membrane until equilibrium is established between the external solution and the gelatin solution inside the bag. The outside solution contains only hydrochloric acid, but the inside solution contains both hydrochloric acid and_ gelatin chloride. At equilibrium, in the outside solution, let
This assumes that the gelatin exerts no osmotic pressure of its own, which may not be strictly true. A correction would have to be made by adding to e an amount corresponding to the osmotic pressure of the gelatin. But Loeb ** has shown that any such correction that may be necessary is less than the probable experimental error of measurement.
When +, y, and zg are determined in the solutions, the osmotic pressure can be calculated. At 24°C. the osmotic pressure, in terms of millimeters pressure of a column of water, equals 2.5¢ X 10°. For casein chloride, Loeb found that the observed osmotic pressure approximated the value 250000e as closely as the determinations could be made.
Because of the unequal distribution of ions between the inside and outside solutions, there must be an electrical difference of potential set up between the two solutions whose measure at 20° C., as in the case of the jellies, is given by the formula
In determining the potential difference between the inside and outside solutions, Loeb used an apparatus similar to that shown in Fig. 47. The collodion bag containing the inside solution was hung in the. beaker filled with the external solution. The manometer tube of the collodion bag was replaced by a funnel. ‘The capillary tube of the right hand calomel cell was dipped into the funnel so as to make contact with the inside solution. ‘Lhe potential difference of the system was then measured by means of a Compton electrometer. S
Osmotic Inside Outside (a) P.D (millivolts ) Moles pressure solution solution minus Calcu- ObNaNO; per liter (mm. ) (a) (b) Ch lated = served INOUE Tt or eee 435 3.58 3.05 0.53 31.2 31 | O.0002d1 tera sine ee 405 3.56 3.08 0.48 28.3 28 ) CL0004BS On se ki cael any 3.51 3.10 0.41 24.0 24 : G.00007 5. oe suse Siew 335 3.46 3.11 0.35 20.7 22 i G.OCLQS oo ecgis none ae 280 3.41 3.14 0.27 16.0 16 ' COD 30 cas ki oats eee 215 3.30 ait7 0.19 11.2 12 ODO070 cae. orca aa ec 134 3.32 3.20 0.12 7.0 7 GORE s 2. Oe aoe 85 3.20 3:22 0.07 4.1 4 OO3T2 cance ces ae 63 3.25 3.24 0.01 0.6 O
Further quantitative proof of the correctness of the theory is furnished by the data in Table XV, showing the depressing effect of increasing concentration of neutral salt upon the osmotic pressure and potential difference of a system in which an acid solution of gelatin is separated from a gelatin-free solution by means of a collodion membrane.*’ The osmotic pressure curve is plotted in Fig. 54. When equilibrium was established, the pH values of both inside and outside solutions were determined and the potential differences were determined in the manner described above. The potential differences were also calculated from the pH determinations, the factor 58.8 being used for 24°. The agreement between calculated and observed results is as nearly perfect as could be hoped for.
With increasing concentration of salt, the pH values of the inside and outside solutions approach each other. According to the theory, the distribution of any ion between the two solutions is similarly affected by the addition of salt; i.c., the logarithms of its concentration in the inside and outside solutions, respectively, approach each other, bringing about a lessening of the difference in total concentration of diffusible ions between the two solutions. It is this effect rather than any supposed repression of ionization of the protein salt that is responsible for the reduction in the swelling of jellies and the osmotic pressure, viscosity, and potential difference of protein systems.
Changes in Viscosity of Gelatin Solutions with Time.
When hot solutions of gelatin are allowed to cool, their viscosities increase with time until they finally set to rigid jellies. Loeb attributes this to the formation of aggregates of gelatin molecules, the viscosity increasing with the average size of the gelatin particles. The curves in Figs. 55 and 56 show that this increase in viscosity with time
10 20 30 40 = 50 10 20 30 40 £50 Time in Minutes Time in Minutes Fic. 55.—Increase in viscosity with Fic. 56.—Change in viscosity with time of 2-per cent solutions of time of 2-per cent solutions of gelatin sulfate of different pH gelatin chloride at different temvalues. ; peratures.
is materially influenced both by the pH value and temperature of the gelatin solution.** The effect of pH value was determined by rapidly heating 2-per cent gelatin solutions containing different amounts of sulfuric acid to 45° C., cooling rapidly to 20°, and then maintaining
this temperature while viscosity measurements were made at intervals of 5 or 10 minutes. An increasing concentration of acid tends to prevent the formation of aggregates; the viscosity increases most rapidly at the isoelectric point.
The effect of temperature was determined by rapidly heating 2-per cent gelatin chloride solutions having a pH value of 2.7, to 45°"G5 cooling rapidly to the temperature at which the viscosity measurements were to be made, and maintaining this temperature while determina-
tions were made at intervals of 5 or 10 minutes. The remarkable point to be observed is that the viscosity increases with time at temperatures below 35° C., but decreases with time at higher temperatures.
Bogue *® measured the viscosities of gelatin solutions at different temperatures by means of a Macmichael torsional viscosimeter. At each temperature he made measurements for a number of different speeds of rotation of the cup. A set of these is shown in Pigess%,
The continuous lines cover the range of actual observation and the dotted portions represent the curves extrapolated to zero speed of rotation. For all temperatures above 34° C. the extrapolated curves pass through the origin, indicating truly viscous flow. But for lower temperatures, the curves do not pass through the origin; they indicate a finite deflection for an infinitesimal speed of rotation, showing that here we have an example of plastic flow. The gelatin solutions at ‘lower temperature actually possess a measurable degree of rigidity. This is further evidence in support of Smith’s view that at temperatures above 35° gelatin in solution exists in a form having no power of gelation. As the temperature is lowered, some of this sol form changes into a gel form which has the power of gelation. As the temperature is lowered, the proportion of gel form to sol form increases until at 15° and lower temperatures all of the gelatin exists in the gel form. The structure of the aggregates of molecules of the gel form is such as to impart to the solution the rigidity observed by Bogue.
When an acid solution of gelatin contained in a collodion bag at 20° C. is brought into equilibrium with a pure aqueous solution of the acid, the solution actually is separated into 3 phases. The gelatin solution within the bag has a hydrogen-ion concentration less than that of the external solution, but greater than that of the solution absorbed by the aggregates of gelatin molecules suspended in the gelatin solu_tion. Loeb *” has shown that, with increasing proportion of aggregates to dissolved gelatin, the variation of pH value produces an increasing effect upon viscosity, but a decreasing effect upon osmotic pressure measurements, as would be expected.
Theory of Salting Out and the Stability of Colloidal Dispersions.
Protein solutions and other so-called emulsoid colloids differ from the suspensoid colloids, such as colloidal gold, in requiring relatively very high concentrations of salt to precipitate their sols. It is generally admitted that the stability of colloidal dispersions is increased by the electrical charge usually associated with the particles. However, but little quantitative work has been done on the actual determination of this charge.
Powis *°.measured the potential difference at the oil-water boundary of an emulsion of cylinder oil and found that the emulsion was stable only when the absolute value of the potential difference exceeded 30 ~ millivolts. When it was reduced to any value lying between plus or minus 30 millivolts, coagulation took place, but at a rate which was independent of the voltage.
It was pointed out by the author *4 in 1916 that Donnan’s theory of membrane potentials is applicable to suspensoids as well as to protein jellies. A gold sol may be taken as a typical example. When gold is dispersed in water, the presence of chloride, bromide, iodide, or
hydroxide ion in concentrations ranging from 0.00005 to 0.005 normal has a marked stabilizing effect on the sol produced and the particles are negatively charged. The effect seems to be due to the ability of these ions to form stable compounds with the gold. Fluoride, nitrate, sulfate, and chlorate ions decrease the stability of gold sols, which is significant in view of the fact that they do not form stable compounds with gold.*?
In Fig. 58 let A and B represent two gold particles stabilized by potassium chloride. In combining with the gold, the chloride ions have imparted their negative charges to the particles. But the potassium ions are still left in solution, although their field of motion is restricted to the thin film of solution wetting the particles because they must continue to balance the negative charges on the particles. The volume
of the film of aqueous solution enveloping a particle will be measured by the surface area of the particle and the average distance that the potassium ions are able to travel from the surface.
Let us now consider the case where an amount of potassium chloride — is present in the sol too small to cause precipitation. The enveloping film will contain potassium ions balancing the charges on the particles as well as ionized potassium chloride. The surrounding solution will have potassium and chloride ions only in equal numbers. In the surrounding solution let
As was shown in the discussion of Donnan’s theory, the product [K*] [Cl’] must have the same value both in the enveloping film and in the surrounding solution at equilibrium. Hence
The surface layer of solution will have a greater concentration of ions than the surrounding solution by the amount 2y + z— 2x. This unequal distribution of ions will give rise to a difference of potential between the enveloping film and the surrounding solution whose
It is thus evident that the difference of potential between the enveloping film and the surrounding solution will be a maximium when there is no free potassium chloride present and will decrease, approaching _ zero, as the concentration of potassium chloride is increased without limit.
between the surrounding solution and each enveloping film. The electrostatic repulsion is determined by this potential difference rather than by the absolute electrical charge on the particles because the surface film completely envelops the particles and endows them with its own properties. |
When enough potassium chloride has been added to lower the potential difference to a point where it is no longer able to overcome the attractive forces between the particles and the surface tension of the enveloping film, the particles move toward each other and the enveloping films of two or more particles blend into one, as shown in Fig. 59. It is at this point that the actual charges themselves come into play and probably determine the nature of the precipitate.
We have now only to substitute for the solid particle with its enveloping film the molecular network with aqueous solution filling up the interstices to make this theory of salting out apply to gelatin and similar proteins.
By referring back to Loeb’s data in Table XV, it will be noted that the potential difference between an acid solution of gelatin and a gelatinfree solution with which it was in equilibrium was reduced to less than one millivolt by the addition of 0.031 mole per liter of sodium nitrate. If we may assume a similar lowering of potential difference between highly dispersed gelatin particles and the dispersion medium by the addition of this quantity of salt, it would follow that coagulation as a function of this difference of potential is not independent of the properties of the disperse phase. A gelatin solution shows no tendency to precipitate in the presence of 0.03 mole of sodium nitrate, but Powis found that his emulsion of cylinder oil ceased to be stable when the potential difference was reduced to 30 millivolts. Halfsaturating a gelatin solution near the neutral point with ammonium sulfate will cause its precipitation, but we have as yet no data indicating the extent to which the potential difference is lowered before the precipitation begins.
Thomas * has called attention to the fact that the stability of colloidal dispersions may be determined more, in some cases, by the attraction between the dispersed phase and dispersion medium than by the difference of potential at the interface. The low degree of attraction between oil and water was probably responsible for the coagulation of Powis’ emulsion at 30 millivolts. Apparently a potential difference of less than one millivolt is sufficient to prevent the precipitation of certain protein solutions because of the attraction existing between the protein and water. The attraction between sugar and water appears to be so great that no potential difference at all is required to keep it‘in solution.
Loeb’s work, taken in conjunction with investigations in the author’s laboratories, indicates that the lowering of the potential difference of protein systems is not brought about by repression of ionization of the protein salts, as has often been supposed, but rather by the mechanism of the Donnan equilibrium just described. In gelatin systems in which the potential difference has been lowered to a very small value, we find no repression of ionization of gelatin chloride measurable by means of calomel electrodes. Moreover, there is no need to postulate such repression in order to account quantitatively for the observed results. |
An application of this theory of salting out to soap solutions furnishes a needed addition to McBain’s** theory of soap solutions, in .which it would be well also to look upon the micelle as an aggregate of monovalent ions rather than as a complex polyvalent 10n.
C. S. Salmon. J.
Ever since Gibbs showed that the concentration of the solute must be greater at the surface than in-the bulk of solution where the solute lowers the surface tension of the’ solution, there has been a tendency to look upon this proof as an explanation of the fact that substances of great specific surface reduce the concentration of solute in many different kinds of solution with which they are brought into contact, The error in this tendency lies in the fact that Gibbs’ work applies only to the lowering of the surface tension by a substance actually in solution. Since, in many cases, it has not been found possible to determine the actual concentration of solute in the layer of solution immediately in contact with the surface of the material causing a> decrease in concentration of solute in the bulk of solution, any con_ clusions as to the causes of such decrease have been open to question. In the case of gelatin, however, it has been found possible to measure concentrations in the absorbed solution and this has thrown considerable light on the phenomenon known as adsorption.
Adsorption is a term now widely used to indicate the removal of solute from solution by a material in contact with the solution. An empirical formula was proposed by Freundlich #® which agrees approximately with some observed results over limited ranges, provided the two constants required in the formula can be selected to suit the findings. The formula may be represented as follows:
where w is the amount of solute removed from solution by unit quantity of the adsorbing material, x is the final concentration of solute, and a and b are constants selected to suit the occasion. Freundlich mentions that b may vary from o.1 to 0.5, but a very much more. ' The very nature of the equation makes it capable of fitting a great variety of data, especially since the constants may be selected as desired, but it doesn’t explain anything. Referring back to Table XI, we find that the total quantity of chloride in the gelatin jelly at equilibrium, represented by V(y ++ z), can be represented as a function of the hydrogen-ion concentration by the use of Freundlich’s formula. Letting V(y + z) = 7.33x°-#?, we can plot a curve for the total quantity of hydrochloric acid, combined and uncombined, which has been absorbed by the jelly that agrees fairly closely with both the calculated and observed results given in Table XI, although not quite so well as do the calculated and observed results with each other. Plotting logV(y +z) of the above equation against logx, we get a straight line, but the observed results never give a perfectly straight line, but vary in the same directions as do the calculated results of Table XI. The curve for the concentration of gelatin chloride shown in Fig. 42 also can be represented approximately by Freundlich’s formula by letting z—o0.10x™*. The formula is a convenient means of represent-
Adsorption, so far as it pertains to gelatin jellies, is a manifestation of chemical combination complicated by the separation of the solution into two phases. We see no reason for looking upon adsorption by other materials in any different light. In the case of suspensoids, we are dealing with two phases of the solution apparently analogous to those of gelatin systems, the film of solution enveloping the particles corresponding to the solution absorbed by the jelly.
For a more elaborate treatment of certain phases of modern theories of the physical chemistry of the proteins, the reader is referred to Loeb’s “Proteins and the Theory of Colloidal Behavior” ** and to Bogue’s “Chemistry and Technology of Gelatin and Glue.” *®
Preservation and Disinfection of Skin.
Practically every country in the world supplies hides and skins for leather manufacture. The skins from large, fully grown animals are usually called hides, those from half grown animals of the larger variety kips, while those from small or very young animals, or those intended for furs, are ¢alled skins. For example, as the calf grows into a cow, its skin remains a skin until it reaches a weight of about I5 pounds in the wet state, when it becomes a kip, while it becomes a hide at about 30 pounds. These figures are necessarily arbitrary, but serve to indicate the general scheme of classifying skins according to size. A bull hide may weigh more than 100 pounds. A sheep skin always remains a skin because it never assumes great size. The skin of the full grown East Indian buffalo is called a kip because it is smaller than the ordinary cow hide. For convenience, the term skin is used in its general sense throughout this book to include hides and kips, except when referring to specific cases.
The fact that animals are generally raised and slaughtered for food rather than for purposes of leather manufacture makes the tanner’s chief raw material a by-product of the packing industry. For this reason a decreasing consumption of leather has but little influence upon the continued supply of skins, although it does tend to lower their market value. On the other hand, a brisk demand for leather generally does not in itself stimulate the raising and slaughtering of cattle, but rather has the effect of increasing the vigilance against damage to the existing supply of skins by putrefaction, careless handling, or the ravages of insects. Raw skins are highly putrescible and, since a considerable period of time usually elapses between the slaughter and the first tannery operation, it 1s necessary to subject them to some method of preservation as soon as possible after flaying.
Salting.
The commonest method of preserving skins, where they do not have to be transported very long distances and where salt is reasonably cheap and plentiful, is salting or curing, as it is sometimes called. The skins are laid out flat, flesh side up, and covered with salt in amount equal to about one quarter of their weight. Often they are placed in piles so arranged that the sides are higher than the center, which keeps the brine from flowing away, but this is undesirable unless
the skins have previously been washed free from blood. Sometimes they are soaked in a concentrated solution of salt first and then covered with dry salt. The object is to get the salt to diffuse completely through the substance of the skins, which may require only a few days for light skins or weeks for heavy hides. Each skin is then folded up, hair side out, and in this condition sent to the market.
Where the blood and lymph have been removed from the skins immediately after flaying and enough pure salt has been used to give a nearly saturated solution in the skins, putrefaction is reduced to an almost negligible degree and the skins may be kept for a long time with comparative safety. Common salt is most widely used, but sodium sulfate and other neutral salts are also effective and actually used in some places.
A defect commonly found in salted skins is the appearance of peculiar stains, usually either rusty brown or greenish blue in color, which are sometimes very difficult to remove and only become intensified and darkened through contact with sulfide-lime liquors or vegetable tan liquors, substantially lowering the market value of the leather. Because they are a source of loss and annoyance to the tanner, efforts have been made, from time to time, to determine their cause
haired skins are pickled with a solution of sulfuric acid and salt, but others are resistant even to this process as ordinarily conducted. These stains received the name salt stains from the general belief that they were caused by the salt used in curing. At any rate, it was appreciated that their frequency of occurrence was influenced by the composition of the salt and the method of its application.
The percentage of stained skins was especially high in those parts of Europe where edible salt is taxed and the salt used for curing must be denatured. The use of commercial aluminum salts, particularly those containing iron, was looked upon with suspicion and the scientific men of the industry began to seek other denaturing materials that would tend to prevent rather than to cause stains.
One important school of thought regarded bacterial action as being largely responsible for the formation of the stains and sought denaturing materials capable of checking bacterial growth. Paessler * found that the percentage of stains appearing on skins could be greatly reduced by curing with salt denatured with 3 per cent of its weight of anhydrous sodium carbonate. His discovery was put into general use and had the important effect of considerably decreasing the percentage of stained skins. : |
Schmidt ? showed that bacterial action could be effectively checked by using salt previously sprinkled with a I2-per cent solution of zinc chloride and this method has been used to some extent to prevent salt
in preventing salt stains.
Romana and Baldracco * suspected the blood and lymph as the source of the stains and tried washing the skins very thoroughly after flaying and before adding the salt. On skins thoroughly washed they found no stains at all. They also found that the stains could be prevented by adding to the salt used in curing 1 per cent of its weight of sodium fluoride.
- Kitner ° suggested that many stains are caused by delaying the salting operation until bacterial action has already considerably advanced. He advised a more thorough elimination of water by heavily salting the skins, draining off as much brine as possible, and then resalting. The brine drained off carries with it proteins which are very susceptible to putrefaction.
Yocum ® observed that salt stains occurred much more frequently in summer than in winter and were most abundant where the skins had had greatest contact with the air or had been kept for the longest period in the salted condition. Tests for iron were obtained on pieces of filter paper previously moistened with acetic acid and placed on the stains. Where stains still appeared on the finished leather, he obtained a test for iron in the stained, but not in the unstained parts. But iron was often found in the ash of fresh skins which showed no stains when tanned at once without salting. This seemed to indicate that the staining was due to a change in the condition of the iron present which enabled it to combine with the skin. He was able to produce stains on skins by treating them with hemoglobin and suggested that the hemoglobin of the blood might have been the source of the staining material.
Becker 7 made extended studies of yellow, orange, and red stains on skins and isolated from them bacteria which, in pure cultures, were able to produce the corresponding stains. He also found that adding salt, up to 10 per cent of the weight of the skin, favored the action of these bacteria, while greater amounts retarded it. He warned against the use of an insufficient quantity of salt in curing, storing the skins in a warm, damp atmosphere, and of allowing dirt and filth to remain on the skins. As a means of preventing these stains, he recommended dipping the skins in a 0.25-per cent solution of mustard oil, followed by the application of plenty of clean salt denatured with sodium carbonate. Not being able to reproduce the blue stains by bacterial action alone, he admitted that these might be due to chemical changes other than those involving bacteria. ,
tained that most of the salt stains he had examined in France were not caused by bacterial action. Particularly bad cases of staining were traced to the presence of crystals of calcium sulfate in the salt used for curing. ‘The stains themselves always contained considerable quantities of calcium phosphate as well as iron. ‘The stained regions always: gave more intense qualitative tests for iron than the unstained regions, but analysis showed the same actual quantity of iron in both. He pictured the stain formation as follows: Calcium sulfate present in the salt used for curing is precipitated as phosphate through contact with ammonium phosphate derived from the nucleic acids of the skin. The ammonium sulfate thus liberated then reacts with insoluble ferrous carbonate, naturally occurring in the skin, forming the soluble ferrous sulfate, which forms a stain by combining with the skin protein.
Abt attempted to follow the progress of the staining under the microscope and found that the cell nuclei disappear as the staining increases. ‘The connective tissues gradually disintegrate, but he could find no bacteria between the altered fibers, nor did the disintegration resemble the type of decomposition producd by bacteria. He thought the iron probably originated either in the chromatin of the cell nuclei or from the blood. A second type of stain contained no calcium phosphate, but the epithelial cells were strongly pigmented. These stains he regarded as due to the fixation of the pigment by mineral matter in such a way as to prevent its decomposition by the lime liquors later on. Abt also recommended adding sodium carbonate to salt to be used for curing because it precipitates the calcium salts present and also exerts an antiseptic and dehydrating action.
Although Abt contended that most of the stains which he had examined were not caused by bacterial action, he admitted that bacteria might play an important part in the formation of other types of stains. In fact, he *° isolated an organism from one stain capable of producing a brown color on gelatin in the presence of traces of calcium phosphate and iron.
At least three different explanations have been offered to account for the effectiveness of sodium carbonate in preventing salt stains. Abt attributed it to the precipitation of calcium salts which might be present in the salt used for curing. Paessler and others looked upon it as due to the production of an alkalinity unfavorable to the action of the bacteria thought to be responsible for the stains. Moeller,?+ however, suggested that the staining is a tanning action, due to such agents as the melanins or to iron and sulfur bacteria, but that this tanning action cannot proceed in alkaline solution. It is, of course, obvious that the sodium carbonate has the important effect of preventing iron salts from passing into solution, in which condition they would be free to combine with the skin forming the stains.
Summing up the work of various investigators, it would appear that salt stains are of several kinds and inay be produced directly by bacteria, such as Becker’s chromogenic organisms, or by soluble iron
salts. These iron salts may be introduced in the salt used for curing or may be formed from the insoluble iron salts already present in the skin, either by chemical action, as described by Abt, or through the intervention of bacteria.- The blood and lymph of skins furnish, an excellent medium for bacterial growth and contain compounds of both iron and phosphates.
The following simple rules represent the best means known to the author for preventing these undesirable stains and, it would seem, ought to be quite effective, if carefully observed at the point of slaughter. Immediately after flaying, the skins should be washed very thoroughly in running water to remove as much blood, lymph, and other soluble matter as possible and then salted uniformly in all parts with plenty of clean salt, free from iron and containing about 4 per cent of its weight of anhydrous sodium carbonate. During the time required for the salt to diffuse completely through the skins, they should be kept in a cool place and the brine formed should be allowed to drain away, carrying with it any soluble proteins not previously washed out. Salt equal in amount to at least one quarter of the weight of the skins should be used. Proper curing of skins is necessary, not only: to prevent the formation of stains, but also to prevent putrefaction that would otherwise impair the yield and substance of the leather.
Drying.
In tropical countries, like Java and India, from which skins are often transported very long distances, the simplest and most economical method of preserving skins is to dry them. ‘This is true for all regions where salt and antiseptics are scarce. Moreover, drying reduces the weight of the skin by about 70 per cent. In the absence of moisture, putrefactive bacteria are practically without action on the skin proteins, although the drying does not always kill the bacteria.
When this method of preserving skins is intelligently controlled, very little damage to the skin results. In hot climates, care must be exercised to prevent excessive heating of parts of the skin which are still wet or the protein matter may decompose. Sometimes skins are dried so rapidly that the outer layers feel quite dry, while the interior is still moist enough to permit putrefaction. Skins packed and shipped in this condition are liable to considerable damage. Defects of this kind usually cannot be detected until the tanner attempts to soak the skins back, when they may actually disintegrate or the grain and flesh layers may tend to separate, due to the hydrolysis of the protein matter in the interior. If the drying has been unduly prolonged at high temperatures, the tanner may have considerable difficulty in soaking the skins back to their normal water content.
The skin tissues continue to live for some time after the death of the animal and, in the living condition, are not readily subject to putrefaction. It is therefore desirable to dry skins as soon as possible after flaying. ‘They should first be cleansed thoroughly by washing away all the blood and lymph and then suspended freely in a current
of cool air until dry. Where conditions are such that drying cannot be effected sufficiently rapidly to prevent putrefaction, as in damp climates, it is customary to treat the skins first with some antiseptic, such as naphthalene, which acts also to protect the skins against the attacks of insects during drying.
The advantages of drying, as a means of preserving skins, are simplicity and speed of operation, independence of a supply of preservative material, and low transportation costs for the skins. The disadvantages are the difficulty of wetting the skins back later to their normal water content, the almost impossibility of detecting damage to the skin proteins until they are wet back, and the fact that dried skins may carry disease-producing bacteria or their spores in a form likely to spread infection.
Salting and Drying.
Sometimes the methods of salting and drying are combined to advantage. ‘The skins are first salted in the usual manner, the brine is allowed to drain away, and they are then allowed to dry slowly. The salt has the effect of hindering putrefaction during the drying.
This method is extensively used in some parts of India, but the salt used is a native earth which, according to Procter,!? consists chiefly of sodium sulfate mixed with sand containing insoluble compounds of iron and aluminum. This material is made into a very thin paste, which is brushed onto the flesh side of the skins. Next day more of the paste is rubbed onto the flesh side of the outstretched skin and rubbed into it with a porous brick. After 3 or 4 saltings, the skins are dried under cover and are ready for export. The iron present in the salt sometimes causes a staining of the skins when they are kept for a long time in a moist atmosphere.
Pickling.
Skins may be preserved by pickling in a solution of sulfuric or hydrochloric acid and sodium chloride. A solution made about N/20 as to acid and 2N as to salt is efficient. This method is not in general use for fresh skins because of the complications involved in attempting to bring them into an alkaline condition later on for unhairing. But for sheep skins, already dewooled, it is a widely used method and convenient, because the skins are then ready for chrome tanning without further treatment.
The value of this method for preserving sheep skins is increased by the fact that wool is often more valuable than the skin. The skins are frequently purchased by wool pullers, who remove the wool by methods to be described in Chapter 8, and then lime, bate, and pickle them, in which condition they are stored or resold to tanners. ‘This method of preservation permits the immediate use of the wool without destroying the skin or forcing it directly into the tanning process.
In pickling, the skins are usually thrown into a vat, equipped with a paddle wheel for keeping the liquor and skins well stirred and containing a strong solution of salt with a definite excess of sulfuric acid, which is controlled by analysis. The skins are left in the pickle liquor until equilibrium has been practically reached, which is determined by noting when there is little further decrease in concentration of acid with time. This may require anywhere from 4 to 24 hours, depending upon the thickness and condition of the skins and upon the equilibrium concentration of acid selected. Equilibrium is reached more quickly when more concentrated solutions of acid are used, but, if too strong a solution is used, it may be necessary to remove some of the acid prior to tanning by washing the skins in a concentrated neutral salt solution. After pickling, the skins are allowed to drain and are then stored in a damp condition until the tanner is ready to put them into process.
Disinfection.
Infectious diseases among cattle are common in many countries, particularly in Asia. For this reason some kind of disinfection of skins to be transported from infected areas is necessary in order to prevent the spread of disease germs. Much attention has been paid to preventing the spread of rinderpest,. foot-and-mouth disease, and. the much dreaded anthrax, which occasionally proves fatal to human beings infected with it. Various governments have issued rules to be followed in disinfecting skins from regions known to be infected. The greatest precautions have been directed against the spread of anthrax because of the danger to human life, but any treatment effective against this disease may be considered effective against the others as well.
The spore, on the other hand, is very resistant to methods of disinfection that do not cause some injury to the skins, and it is this that makes the problem of disinfecting skins a difficult one. Anthrax spores have been found in dried skins and in blood clots on hair and wool, but seldom, if ever, in wet salted skins.
Practical methods of disinfection are limited because so many disinfectants are injurious to the skin and reduce its value for leather making. Consequently only a few workable methods have been devised. Of these, the best known is that of Seymour-Jones,'* who recommends its employment at the point of export rather than of import because of the danger of spreading the disease during transit. It consists in soaking the dried skins for from I to 3 days in a I-per cent solution of formic acid containing 0.02 per cent of mercuric chloride. They are then soaked for an hour in a saturated solution of common salt, drained, and baled for shipment.
Procter and Seymour-Jones?* studied the rate of absorption of formic acid and mercuric chloride during the soaking operation at a . number of different concentrations, using 1 liter of solution per 100 grams of dried skin. The concentration of acid in the solution always fell slowly during a period of 20 hours, but that of the salt at first increased and then dropped, finally approaching a limiting concentration. The initial increase in concentration of mercuric chloride was. found to be the result of a greater initial rate of absorption or pene-
Process for sterilizing skins.
tration of water and acid than of the salt. The results of one of their experiments are shown in Fig. 60. a The absorption of water caused by the acid renders the skin almost as soft as in the fresh state and the subsequent immersion in saturated sodium chloride solution brings it into a condition resembling that of salted skins. Seymour-Jones points out that skins in this condition are not only properly disinfected, but that they present less of a gamble to the tanner because they show any defects in the skin that would not be visible when the skin is in the dried state. aS Schattenfroh ‘® proposed a method of disinfection involving the © Seymour-Jones Anthrax Sterilization Method. H. R. Procter and Arnold Seymour-
soaking of infected skins in a solution containing 10 per cent of sodium chloride and 2 per cent of hydrochloric acid at 40° C. for 3 days. Much debate has waged over the relative merits of the Seymour-Jones and Schattenfroh methods. Tilley,’ after experimenting with both methods, concluded that the Seymour-Jones process is effective, but only provided the concentration of mercuric chloride is as high as 0.04 per cent and the skins are not subjected within a week to treatment with sodium sulfide or other substance that would neutralize the disinfectant. It should, therefore, be effective where the disinfection is carried out at a foreign port before shipping. Seymour-Jones,'* in reply, pointed out that neutralization of the disinfectant by sodium sulfide would take place only in the unhairing process, whereas, under conditions existing during this process, the sodium sulfide itself is a | perfect sterilizer of anthrax spores. This would seem to eliminate any possible danger of anthrax infection from skin or leather that had passed through the usual lime and sulfide method of unhairing.
Tilley found the Schattenfroh method effective when the hides were allowed to remain in the acid-salt solution for 48 hours or longer. Schnurer and Sevcik,?® however, applied the Schattenfroh process to very heavy hides and obtained 4 positive tests of infection out of 11 made after the hides had been in a solution containing 2 per cent of hydrochloric acid and Io per cent of sodium chloride for 72 hours. They attributed the more favorable results obtained by Schattenfroh to the fact that he experimented with very thin skins. Using the Seymour-Jones process on very heavy hides, they found it. necessary, in order to get complete sterilization in 24 hours, to increase the concentration of mercuric chloride to 0.2 per cent, but hides so treated were found by Eitner not to have suffered for tanning purposes. They also found it necessary to degrease heavy sheep skins before applying the Seymour-Jones process, as otherwise a ten-fold dose of mercuric chloride was required.
Seymour-Jones objected to the Schattenfroh method on the ground that it is workable only under laboratory conditions and that its factors of time, temperature, and general manipulation are not suited to practical operations. Ponder,?? investigating methods of disinfection for the Leathersellers Company of London, and Abt,*4 of the Pasteur Institute, Paris, working for a syndicate of French tanners, both reported in favor of the Seymour-Jones process. Apparently neither process does any injury to the skins that can be detected in the finished leather, according to the findings of numerous investigators.
Abt, however, has pointed out that hides would contain no anthrax spores, if they were dried in the sun immediately after flaying, and this view is supported by Seymour-Jones.
As received at the tannery, skins contain much material unsuitable for leather manufacture and which would introduce serious complications, if not removed as early in the process as possible. For this reason every effort is made to remove each undesirable constituent as soon as it can be done efficiently. The preparation of skin for tanning is carried out in a department of the tannery known as the beamhouse and includes, not only the removal of the undesirable parts, but also the regulation of the degree of swelling of the skin proteins.
Ears, cheeks, hoofs, and tails are trimmed from skins still possessing them and the flesh, or adipose tissue, is removed by working the skin in a fleshing machine, which forces the flesh side of the skin against a revolving roller set with sharp blades, which cut away the adipose layer. The trimmings and fleshings make up the tannery by-. product known as glue stock and are disposed of for manufacture into glue and gelatin.
On the hair side of the skin, the epidermis is made up of a network of membranes, forming the walls of the epithelial cells, impermeable to the soluble proteins of the skin as well as to other material having large molecules or consisting of aggregates of molecules, while on the flesh side the adipose tissue consists of layers of fat cells bound together by extensive series of semi-permeable membranes. It will, therefore, be readily appreciated why the adipose tissue must be removed before the skin can be thoroughly cleansed and freed from soluble protein matter. ;
The collagen fibers of the skin are joined together at the lower boundary of the derma in such manner as to give increased strength to the skin. In fleshing, it is important to remove all of the adipose tissue without cutting into the derma, which would weaken its structure as well as lower the leather yield. But reference to Fig. 7 will show: that this is not difficult where the skin is in its normal state. The lower boundary of the derma is sharply defined and the adipose tissue is not joined securely to it at all points. But where the skin has undergone partial or complete drying, satisfactory fleshing becomes a more difficult operation.
During the ordinary methods of drying, protein jellies suffer a change of shape, as well as of size, depending upon their initial shape, the resistance offered to shrinkage in any direction, the rate of drying, and many other factors. This was prettily illustrated by Sheppard
SOAKING AND FLESHING 143
and Elliott! with blocks of gelatin jellies. The photographs shown in Figs. 61 to 64 were kindly furnished by Dr. S. E. Sheppard of the Eastman Kodak Co. Fig. 62 shows four stages in the drying of a cube of 20-per cent gelatin jelly which was freely suspended in the air. No. 1 represents the original block of jelly, Nos. 2 and 3 intermediate stages in the drying, and No. 4 the dried block. At first the drying naturally proceeds most rapidly at the corners, or trihedral angles, and the faces of the cube become curved outward, as shown in No. 2, giving convex surfaces under tension. This is rapidly followed by the drying and hardening of the edges, forming a rigid framework, so that the bulk of the jelly now behaves as though suspended inside of a rigid wire frame. The faces now gradually recede and the edges become somewhat incurved until a sort of inner cube is formed with connected flanges reinforcing it, any cross-section through this having an J-beam structure, as though the drying proceeded in a manner developing the greatest resistance to stress. The flange-like edges appear to form sections of hyperboloids with a common focus at the center of the cube. Fig. 61 shows three stages in the drying of a sphere of gelatin jelly. Even here the drying is not uniform, but the surface becomes puckered and wrinkled.
The dried forms of two cylinders of gelatin jelly are shown in Fig. 64 and their end views in Fig. 63. One base of the first and both bases of the second cylinder were allowed to adhere to rigid surfaces during the drying. The shrinkage in area of these bases being prevented, the reduction in volume had to be compensated by greater shrinkage in other directions. In the drying of a thin coat of gelatin jelly on a glass plate, the shrinkage takes place almost entirely in the direction perpendicular to the plane of the glass surface.
Upon soaking dried blocks of gelatin in water, the swelling proceeds in the direction counter to that followed during drying and the blocks tend to assume the shapes and sizes they possessed before drying.
During the drying of skin, the distortions of shape suffered by the insoluble protein constituents are further complicated by the tendency for the fibers to adhere to each other. Before a skin can be fleshed satisfactorily, it is necessary to soak it in water long enough so that all of the insoluble protein constituents may swell to their normal sizes and shapes. When the skin is not uniformly swollen, the boundary between the derma and adipose tissue cannot be made to lie in a single plane. The fleshing machine would then cut the skin so as to leave the flesh side apparently smooth, but in so doing would either leave a considerable amount of adipose tissue on the skin to interfere with the proper cleansing of the skin or else injure the skin by cutting into the derma. The flesh side would look smooth enough upon coming from the machine, but would be ragged and irregular in thickness after the skin had been soaked further or swollen in the liquors used later. F. L. Seymour-Jones says that in Europe it is customary not to flesh
goat skins usually flesh them after liming.
Heavy, dried hides not only require a more drastic treatment than light, fresh skins, but are also better able to stand it without injury to the resulting leather. In order to get better and more uniform results, the tanner sorts the skins he receives according to weight and general condition. A suitable number of skins, all as nearly alike as possible, are assembled into a unit lot and kept together throughout the process. The treatment is then determined by the average size and condition of the skins as well as by the kind of leather desired. Very large hides are often cut into two sides along the line of the back bone, for convenience in handling.
Where the skins come to the tannery in a perfectly fresh condition, the soaking and fleshing operations are extremely simple. After the skins have been trimmed, the adhering blood and dirt are removed by tumbling the skins for half an hour or more in an open drum through which water is flowing. They are then fleshed, after which they are soaked in several changes of clean, cold water containing salt or a small quantity of alkali, the object of which is to free them from soluble protein matter that would otherwise coritaminate the liquors used to loosen the hair and epidermis. The purpose of the salt, or alkali, is to render the globulins soluble so that they may be removed along with the albumins.
For dried, or partially dried, skins it 1s necessary to soak the skins both before and after the fleshing operation. The first soaking is primarily for the purpose of swelling the insoluble proteins back to their normal sizes and shapes so that the fleshing operation may be carried out efficiently. The second soaking is for the purpose of freeing the skin from soluble protein matter.
The time required for the first soaking depends upon the extent to which the skins have been dried. Completely dried skins absorb cold water extremely slowly. Since skins, as received at the tannery, are almost invariably contaminated with proteolytic bacteria, the use of warm water in soaking is somewhat risky, unless the process is very carefully watched. It is usually preferable to hasten the swelling of dried skins by adding small quantities of acid or alkali to the soak waters.
Because of the attention centered on the Seymour-Jones process of disinfecting skins, described in the preceding chapter, formic acid has often been used as a swelling agent, although other acids can be used equally as well by applying a simple system of chemical control. Alka_ lies, however, are more suitable where the skins are subsequently to be treated with alkaline liquors to loosen the hair. Sodium sulfide is most commonly employed to swell dried skins because it requires less careful control than the use of more caustic materials, such as sodium hydroxide. In soaking, a gallon of water is usually used per pound of wet skin or for one-fifth of a pound of completely dried skin. Making the initial concentration of alkali about 0.02 normal is usually enough to initiate the swelling without causing damage either to the skin cr the hair. The
solution after using is then only very faintly alkaline, the greater portion of the alkali having combined with the protein matter. The alkaline liquor is used only for the first soaking after which the skins are moved into fresh water each day until swollen to normal.
Sometimes the absorption of water and softening of the skins is assisted by tumbling them in revolving drums with water between successive soakings. This is usually done with heavy, dried hides or sides.
As a rule, salted skins can be fleshed after soaking for only one day, or less. After fleshing, it has been the custom to soak the skins in successive changes of water until practically all of the salt has been removed. ‘The salt diffuses out from the skin much more rapidly than the soluble protein matter, so that continuing the soaking until all of the salt has been removed is not unduly prolonging the process where it is desirable to free the skin as far as possible from soluble protein matter. This custom, however, has created a widespread, but erroneous, impression that it is dangerous to carry salt into the lime liquors. On the contrary, salt assists in the unhairing and plumping of skins by the ordinary lime liquor. Its action in this respect appears to be due to the fact that it increases the hydroxide-ion concentration of alkaline solutions in general.’ 7 :
Defects in finished leather are often traceable to the soaking operation. Although bacterial action is the chief source of danger, the skin may suffer from other causes. The tissues of the body do not necessarily die with the animal, but may continue to live for an indefinite period, if sufficiently well supplied with nourishment. For this reason it is conceivable that the sudden chilling of a fresh skin may exert an effect upon the muscles and glands of the thermostat layer. If, for example, the erector pili muscles were suddenly contracted and paralyzed by chilling, the result would be a permanent roughening of the surface of the skin. There have been cases where an unusual roughness of the grain surface of leather seemed to result from the sudden immersion of the warm skins, before tanning, in water near the freezing point. But the danger from proteolytic bacteria makes the use of warm water undesirable for soaking. Cold water should be used, but the operations should be so conducted that the temperature of the skins falls eradually. :
How long the various parts of the skin continue to live and function after the animal has been flayed remains to be determined. We do know, however, that the skin undergoes changes of one sort or another practically from the moment of flaying. McLaughlin? noted that the rate of swelling of hide in saturated lime water decreases during the first two or three hours following the flaying of a freshly killed animal. A strip of hide put into lime water containing undissolved lime in excess 30 minutes after flaying swelled about 30 per cent more in 120
after the flaying.
This is, of course, not surprising in view of the fact that many changes are known to occur in skin, after the death of the animal, all of which would tend to retard the swelling in lime water. The coagulation of the blood, during which fibrinogen is converted into fibrin, would tend to retard the penetration of lime into the skin and the partial drying of some of the tissues would act in a similar manner. Decomposition of some of the protein constituents would yield simpler bodies capable of forming salts of calcium, which would serve to repress the swelling of the proteins by calcium hydroxide. It is possible also that some of the proteins capable of swelling are gradually broken down into simpler bodies not having the power to swell.
Where the preservation of a skin has been done carefully and intelligently, these changes appear not to have any detrimental effect upon the leather produced. The author has tested this by comparing the tannage of skins properly preserved and kept for months before tanning with the tannage of skins put into process within an hour of the death of the animals; no appreciable differences could be detected by chemical, physical, or microscopical examinations of the final leathers. But where there is carelessness in handling, the skins may suffer irreparable damage before the soaking operation has been completed.
The commonest source of danger in soaking is bacterial action. Although the inner surface of the skin on the living animal may be free from bacteria, it acquires them from the atmosphere very rapidly from the instant of flaying and acts as an ideal medium for the reproduction of bacteria. By the time the skin reaches the soak vats, it is usually contaminated with countless millions of bacteria. Many species of these bacteria are known to secrete enzymes, which may prove as harmful as the bacteria themselves. The chief practical object to be gained from a study of the bacteria common to tannery soak waters is to find means of destroying them, or at least of preventing them from doing any damage to the skins. An extensive series of investigations of the bacteria and enzymes present in tannery liquors has been made by Wood.*
SoleclusMecleclesles
* Properties and Action of Enzymes in Relation to Leather Manufacture, J. T. Wood, J. Ind. Eng. Chem. 13 (1921), 1135. ; ° Der Gerber, 1895-6; J. Soc. Chem, Ind., 1896-7.
variety of enzymes, many of which act energetically on hide substance.
Fig. 65, taken from Wood’s paper, shows a typical plate culture on gelatin of a soak water used for softening dried sheep skins, in which no chemicals were used. The development of the colonies had to be stopped by the application of formaline vapor before many of the species had time to develop; otherwise the whole plate would have been liquefied.
Rideal and Orchard ® examined the action of B. fluorescens liquefaciens on gelatin to which had been added Io per cent of Pasteur’s solution to serve as nutrient medium. The gelatin was completely liquefied in three and one-half days. It was shown that the liquefaction of the gelatin was due to an enzyme secreted by the bacteria. The liquefied gelatin was alkaline and had a slight odor suggesting putrefaction, but contained no hydrogen sulfide. A notable feature was the small amount of ammonia and volatile bases produced; only 0.2 gram of ammonia per 100 cubic centimeters was produced even after 16 days’ incubation.
In bacterial action of a certain type, one of the first effects to be noticed is the loosening of the hair, a condition known to the trade as hair-slippiness. Either the bacteria, or the enzymes which they secrete, act upon the soft epithelial cells of the Malpighian layer of the epidermis, liquefying them and thus effecting a separation of the whole of the epidermis and hair from the rest of the skin. This action alone is not harmful, but the bacteria develop rapidly and soon begin to attack the fibers in the grain surface and the skin is permanently injured. ‘This effect shows itself in the finished leather in the form of dull spots, or what is known as pitted grain. In some cases the bacteria attack the heavier collagen fibers without injuring the fibers of the grain surface. When the bacteria attack the proteins of the thermostat layer, they weaken the connection between the fibers of the grain surface and those of the reticular layer; in the finished leather the grain surface then tends to peel off and its looseness of connection with the main body of the skin gives it the appearance known as pipy grain. :
Chemists not familiar with the chemical composition of fresh skin sometimes fall into the error of assuming that the presence of nitrogenous matter in a used soak liquor indicates that the collagen fibers have been attacked. One of the objects of soaking skins is to remove the soluble proteins so that they will not be carried forward to contaminate the liquors used to loosen the hair.
Bacteria may become lodged just under the grain surface of the skin and resist the action of the various liquors through which the skin passes. They then become the source of many most annoying troubles. They may produce dull spots or stains or hydrolyze the fats used later to soften the leather. Hydrolyzed and oxidized fats are the _ common sources of spews appearing on the surface of finished leather.
In the use of what is known as the putrid soak, bacteria are put to work by being made to assist in the softening of dried hides. But this method is not only an obnoxious one, but one so difficult to control that some damage very often accompanies the softening action. The method is seldom used in modern countries, but in some parts of India dried skins are softened by soaking them in putrid pools of liquor containing all kinds of tannery refuse.
to prevent bacterial action in the soaking operation. In a study of the effect of hydrogen-ion concentration upon the activities of putrefactive bacteria, the author has found that they are most active between the pH values 5.5 and 6.0. This probably explains the value of using alkaline soak waters; the liquefaction of skin by bacteria at a pH value of 5.5 is usually greatly retarded or even completely checked by raising the pH value to 12. A similar effect is observed by lowering the pH value to about 3 by the addition of acid.
Procter’ has pointed out the advantages of using sulfurous acid in the soak waters. It assists in the absorption of water by the skin and at the same time prevents bacterial action. He found that no putrefaction takes place, even if the skins are later retained for a considerable time in water, and the acid has little or no solvent effect on the collagen fibers, whose strength is well preserved.
Alkalies are about equally effective as acids both in the softening of dried skins and in checking bacterial action and are generally preferred because they assist rather than retard the action of the lime liquors in loosening the hair. 3
Aside from the use of acids and alkalies, the chief precaution taken against bacterial action in the soaks is the use of plenty of clean, cold water. If the temperature of the water is not allowed to rise above 1o° C. and plenty of clean water is used, the skins are not likely to ' suffer any serious damage from the soaking operation itself.
Unhairing and Scudding.
After the skins have been trimmed, cleansed, freed from adipose tissue and soluble matter, and have again become soft through absorption of their normal water content, they are ready for the series of operations involved in the removal of the epidermal system. It will be recalled from Chapter 2 that this system includes the epidermis, hair, and the sebaceous and sudoriferous glands and differs from the true skin under it in origin, structure, method of growth, and chemical composition. The several parts of the epidermal system differ markedly in their resistance to chemical reagents and it is rather fortunate for the tanner that the part most readily digested is the portion of the Malpighian layer resting on the grain surface. When the epithelial cells of this layer are destroyed, the rest of the epidermis and the hair become completely separated from the true skin and can easily be removed mechanically.
What is probably the oldest method known for unhairing skins received the name sweating from the nature of the process in its more highly developed state. It consists of little more than the putrefaction of the cells of the Malpighian layer. Since it is only necessary to allow a fresh skin to remain for a day or two in a warm, damp place to cause a loosening of the hair, the method was probably discovered very early in the history of the human race. It is not improbable that the accidental discovery of this action first revealed to the ancients the advantages of unhaired skins for certain purposes.
‘Because of the danger of serious damage to the skins in the sweat chambers, unless the process was very carefully watched and controlled, it ceased to be popular for the best grades of skins after safer methods of unhairing were devised. It is still in use in some tanneries for the lower grades of skins, such as the cheaper classes of dried hides and sheep skins where the wool is valued more highly than the skin.
The skins are generally hung from beams in a closed room in which the air is kept warm. and humid. The temperature, humidity, and ventilation must be carefully controlled. During the process a considerable quantity of ammonia is evolved and this assists in the unhairing action. Just as soon as the hair slips easily, the skins are removed from the sweat chamber and dumped into saturated lime water. The lime water serves to retard further bacterial action and to cause the skins
the sweat chamber are in a very flaccid and slimy condition.
Wilson and Daub? recently made a study of the sweating process under the microscope. Pieces of fresh sheep skin were kept in a closed receptacle having an atmosphere saturated with water vapor at 38° C. At frequent intervals strips of skin were removed for sectioning and examining under the microscope. At the end of 42 hours, the wool could be rubbed off with ease and the skin had apparently suffered no damage. The odor of ammonia in the receptacle after the first day was very pronounced. |
The first sign of action visible under the microscope was the separation of the cells of the Malpighian layer from one another and from the surface of the derma. This action gradually spread to the outermost layers of cells of the sebaceous and sudoriferous glands. On the second day the action had proceeded so far that the epidermis, glands’ and wool were completely separated from the derma and many of the epithelial cells had completely disintegrated. A section of the skin after being in the sweat chamber for 42 hours is shown in Fig. 66. The upper portion of the section is shown in Fig. 67 at a much higher magnification.
It will be noted that the corneous layer is still intact, but the Malpighian layer has almost completely disintegrated, the linings of the hair follicles are broken up, and the glands have all been loosened and separated from the derma. Fig. 66 should be compared with Fig. 28, which represents a section from the same skin fixed in Erlicki’s fluid within an hour after the death of the animal.
In practice, the systematic cleaning of the sweat chambers is necessary in order to prevent the increase of undesirable organisms that may be carried in from time to time. Hampshire? investigated the cause of a pitting, or liquefaction in spots, of the grain and flesh surfaces of sheep skins, a damage known to the trade as run pelts. He found that the pitting was caused by several species of wormlike organisms belonging to the family Nemathelminthes and growing to a length of about one millimeter. Apparently they are killed by simple drying. They were found in great numbers in the sweat chambers, but not on skins which had not yet entered the chambers. In laboratory experiments, they produced a pitting of the skin in the presence of a small amount of ammonia, such as is always present in the sweat chambers. It was found that uniform slipping of the wool could be produced by incubating the skin in a clean vessel which excluded all organisms other than those present on the incoming skin, and skin treated in this way was free from pitting. It would seem that the danger of run pelts can be completely avoided by making certain of the cleanliness of the sweat chamber before the skins enter.
Upon coming from the sweat chamber, the skins are usually put
*The Mechanism of Unhairing. J. A. Wilson and Guido Daub. Presented before th Leather Division at the 64th meeting of the American Chemical Society. Publication ee photomicrographs reserved for this book. :
into saturated lime water and left there for a few hours or over night. Although this treatment is not essential and is sometimes omitted, it has the advantage of decreasing the danger of damage to the skins through putrefaction. The next step is the actual removal of the hair and epidermis. In modern practice, this is accomplished by means of an unhairing machine in which the skin is backed by a rubber slab and blunt knife blades pass over the hair side, under low pressure, rubbing
rotate as they pass over the skin.
The skin is then placed over a beam and scudded. The beam, from which the beamhouse derived its name, is a convex wooden slab sloping upward from the floor, at an angle of about 30°, to a point about three feet higher, which gives it a length of about six feet. The beamster, leaning over the beam, pushes a specially designed, two-handled knife over the skin downward and to left and right, forcing the remnants of the glands, lime soaps, dirt, and any remaining hairs out of the hair follicles and pores.. This operation is known as scudding.
operation, but the author knows of no machine that can replace a good beamster for scudding calf skins after liming. Scudding can usually be done better by hand than by machine because the hair follicles slope in many different directions. If the knife stroke is made in the direction of the hair, from root to tip, the dirt in the follicles is easily squeezed out, whereas there is a tendency for-it to be trapped by a stroke in the opposite’ direction. There is a sufficient degree of transparency to a limed skin to enable the beamster to see the dirt and pigment in the follicles and he directs his knife first one way and then another until the skin appears clean. He is also on the lookout for fine hairs not removed by the machine. The bulb of a new hair is as deeply seated as that of an old one, but there may not be enough of the new hair protruding above the surface of the skin to be gripped by the knives of the unhairing machine.
After the scudding operation, the skins are washed thoroughly to remove as much lime as possible. This washing is of considerable importance because any great excess of lime carried forward interferes with the later processes. It is customary to wash the skins in a revolving drum through which fresh water is continually passing. Wood ® followed the removal of lime during washing and showed that little is to be gained by continuing the washing for more than two hours. The tendency, however, is to wash the skins for a shorter time than this and to take care of the residual lime by other means. Fig. 68 shows the extent of lime removal with time during a typical washing operation. The lime left in the skins appears to approach a limiting value, due to the lime which has carbonated as well as that in chemical combination with the skin.
Liming.
The commonest method in use today for effecting the separation of the epidermal system from the true skin is also one of ancient origin and is known as liming from the fact that saturated lime water is used. Formerly a lime liquor was prepared simply by filling a vat with water and adding calcium hydroxide greatly in excess of saturation. The skins, after soaking, were put into this liquor and allowed to remain there until the hair and epidermis had become so loosened that they could be rubbed off with very little pressure. Often the skins were removed each day and fresh lime added in order to hasten the action. But with a fresh lime liquor it usually required weeks for the skins to get into a state where the hair would slip easily. It was discovered that less time was required for each succeeding lot of skins passing through a given liquor. The longer a liquor was used the more it became charged with ammonia, other protein decomposition products, bacteria and enzymes, all of which assisted in loosening the hair, The older liquors, however, attacked the collagen fibers to a greater extent and also produced less swelling of the skin proteins than fresh liquors.
As more was learned of the action of lime liquors, it became cus-tomary to employ a series of liquors for each lot of skins. The skins were put first into the oldest liquor in order to start the loosening of the hair. Each day they were moved into a fresher liquor and finally into one quite fresh. This system is still in use in some tanneries, but the modern tendency is toward quicker methods.
When lime alone was used in making lime liquors, it usually required from one to three weeks to cause the hair to slip easily, during which time a considerable amount of collagen became hydrolyzed, especially in old liquors or in liquors not kept completely saturated with lime at all times. Bacteria are very sensitive to changes in pH value and many proteolytic bacteria present in lime liquors which are comparatively inactive at a pH value of 12.5, that of an ordinary lime liquor, become very active as the pH value falls to lower values. In order to guard against the danger of incomplete saturation of the liquors with lime, mechanical agitators have been devised, one of the simplest being a paddle wheel set in the vat. By keeping the undissolved lime continually stirred up, the solution is kept almost at the saturation point.
With increasing demand for speed of operation and conservation of the skin collagen, sharpening agents have come into wide use, the principal ones being arsenic sulfide, sodium sulfide, and sodium hydroxide. The judicious use of these materials, in conjunction with lime, has reduced the time required to unhair skins from weeks to as many days. More attention was paid also to temperature. In some of the old tanneries not equipped to heat the liquors, a much longer time had to be allowed for unhairing in winter than in summer. It 1s now customary to maintain a uniform temperature of from 20° to 25° C. the year round.
Arsenic disulfide was one of the first sharpening agents to be employed. It was mixed with the lime before slaking in the proportion of about one part of sulfide to twenty-five parts of lime and from this mixture a liquor was made of such concentration that the hair would not be damaged, but would slip easily in two or three days. Sodium sulfide is now used more commonly than arsenic, being cheaper and somewhat more effective in loosening the hair. It is used at about 0.01 molar concentration in a solution kept saturated with lime.
The action of a lime liquor sharpened with sodium sulfide upon a calf skin is illustrated in Fig. 69. A fresh calf skin was put into a solution containing 0.7 gram of Na,S per liter and calcium hydroxide well in excess of saturation. The liquor was agitated frequently and kept at a temperature of 25°C. Strips of the skin were examined at intervals as in the study of the sweating process. The skin from the sweating process was in a soft, flaccid condition, while that from the lime liquor was plump and rubbery, but the fate of the epithelial cells of the Malpighian layer was the same in both cases. Sections of specimens taken at intervals showed these cells slowly disintegrating and leaving the corneous layer, hairs, and glands separated from the derma. Fig. 69 shows a section taken after the skin had been in the lime liquor for 48 hours. Part of the upper region of the section is shown at
in life.
The lime has completely destroyed the Malpighian layer of the epidermis and the corneous layer appears as a nearly continuous line somewhat separated from the true skin. The epithelial cells of the hair follicles have been completely broken up leaving the hair, with adhering patches of corneous layer, free to be swept out by the action of the unhairing machine. The sudoriferous glands have disintegrated, leaving empty spaces, and the sebaceous glands may be seen lodged in pockets opening into the hair follicles. The erector pili muscles are still intact and can be seen runing upward to the left from the region of the hair bulbs. In the thermostat layer, as well as in the deepest layer of the skin, the elastin fibers appear as fine, black threads. These fibers do not appear prominently in Fig. 18 because this section was stained with the object of showing greater detail in other parts.
Although the hair loosening operation can be effected easily in a single liquor acting for two or three days, some tanners still prefer to use a series of liquors, claiming that they get a result better adapted for the particular kinds of leather they desire to make. They lessen the extra amount of labor involved in handling the skins by a system of reeling from vat to vat. The skins are all hooked or tied together, the head of one to the tail of another, and the whole lot is passed over a reel from one vat to another, the last skin in being the first to come out. The skins are put first into the oldest liquor and then reeled into a fresher liquor each day until ready to be unhaired.
Plumping and Falling.
When animal skin is immersed in dilute solutions of acid or alkali, the protein matter ‘swells by absorbing some of the solution, but the effect to a casual observer is not so much one of swelling as of increased resiliency of the skin, due to its fibrous structure. ‘The collagen fibers, in swelling, tend to fill up the interstices between them and the full increase in volume of the protein matter is not evident from the appearance of the skin. .A skin in which the fibers are not swollen may con-_ tain practically as much water as one whose fibers are swollen, as in lime water, but the bulk of the water in the first skin is held only loosely between the fibers and may be squeezed out by the application of slight pressure, whereas that in the second is present within the substance of the fibers, like the water absorbed by a solid block of gelatin jelly, and cannot be removed, except by the application of enormous forces. During the swelling of the protein matter, the tanner observes in the skin an increasing resistance to compression, to which he has given the name plumping, the term falling indicating the reverse action.
a skin had become completely fallen during the bating process which consisted of a sensitive thickness gauge in which the pressure exerted upon I square centimeter of skin could be varied by means of weights. The point of complete falling of a skin was taken as that at which no recovery in thickness of the skin took place upon removing the weights. The apparatus was also used to measure the apparent modulus of elasticity of the skin and this was considered to be a measure of the degree of plumping.
This method suggested to Wilson and Gallun® another which is more suitable for certain purposes. Their apparatus consisted of a Randall and Stickney thickness gauge ** with a flat, metal base upon which a small piece of skin could be placed, and a plunger, having a circular base I square centimeter in area, capable of pressing on the surface of the skin under constant pressure. The apparent thickness of the skin, as shown on the dial of the instrument, being determined by the position of the plunger, decreased with time as the plunger caused an increasing degree of compression. For this reason and in order to get comparative readings, all gauge readings were taken a fixed length of time after dropping the plunger onto the skin. In order to measure the degree of plumping of skin in a given liquor under fixed conditions, they first measured the resistance to compression of a small piece of skin under standard conditions. This same piece of skin was then subjected to the conditions of the test and its resistance to compression measured again. In each case the gauge reading was taken as a measure of the resistance to compression. The ratio of the final to the initial gauge reading is a measure of the degree of plumping of the skin. Their measurements of the degree of plumping of calf skin as a function of pH value are given in Chapter 9.
If a skin in the alkaline state is plumped or swollen excessively, it suffers permanent distortion and the value of the final leather is lowered. Some knowledge of the degree of plumping of skin in liquors used for unhairing is therefore much to be desired.
Atkin ® was able to reason from the work of Procter, Wilson, and Loeb, which was discussed in Chapter 5 in connection with the swelling of protein jellies, that arsenic disulfide is preferable to sodium sulfide for certain kinds of skin where fineness of grain surface is of paramount importance in the finished leather. Loeb showed that diacid bases produce a maximum swelling of gelatin jelly only half as great as that produced by monacid bases. Atkin confirmed this for the swelling of hide powder and showed that the weak base ammonium hydroxide produces as much swelling as sodium hydroxide at the same pH values. When arsenic disulfide is slaked with lime and used in a fresh liquor, the solute consists only of calcium hydroxide, calcium sulfhydrate, and calcium sulfarsenite. But when sodium sulfide is used as the sharpening agent for a lime liquor, sodium hydroxide and -sodium
sulfhydrate are present. It would therefore be expected that the use of sodium sulfide would result in a greater plumping of the skin than the use of arsenic sulfide, which gives a liquor containing only divalent cations. In actual practice, when arsenic sulfide is used to sharpen lime liquors for the unhairing of goat skins in the manufacture of glazed kid leather, the final leather has a smoother and silkier grain surface than when sodium sulfide is used in the lime liquors.
It might be inferred from this that it is preferable to use arsenic sulfide for all kinds of skin where smoothness of grain is desired, but this is not necessarily so. All skins are not equally sensitive to injury through plumping. What may prove to be excessive plumping for goat skins may not have any deleterious effect at all on a calf skin and one type of calf skin might be more resistant to permanent distortion than another. The greater speed of action and lower cost of sodium sulfide makes its use preferable in all cases where it does no harm to the skins.
It sometimes happens that a skin can be unhaired less readily the more it is plumped. This seems to be due to the overlapping scales of the hair, which open upward as shown in Fig. 6. When the skin is put into a liquor in which it swells considerably, the hair becomes tightly pinched by the skin and at the same time the scales become distended, their ends wedging themselves into the sides of the follicles in such manner as to resist any attempt to pull the hair out. If the fine hairs are not removed from a skin while it is still in the alkaline condition, but are allowed to remain in place until after the tanning operation, they again become firmly fixed in place, apparently because of the distention of the hair scales and the permanent plumping of the skin produced by the tannage.
Fresh vs. Mellow Lime Liquors.
A much used lime liquor, charged with decomposition products of the skin, bacteria and enzymes, is usually referred to as mellow. Where unsharpened lime liquors are used, a mellow liquor causes a much more rapid loosening of the hair and much less plumping of the skin than a fresh liquor. This difference is not due to any difference in hydroxideion concentration for Wood and Law? have shown that a mellow lime liquor has a pH value practically the same as that of pure saturated lime water. They found also that the pH value is but little affected by the addition of small quantities of sodium sulfide and this has been confirmed in the author’s laboratories. The decrease in plumping power of a lime liquor with use may be ascribed to the calcium salts formed, which tend to repress the swelling of proteins by calcium hydroxide. But the increasing power to loosen the hair must be attributed to the protein decomposition products, bacteria, enzymes, or the lesser swelling of the skin at the same pH value, or possibly to a combination of all four factors. |
an old lime liquor in which skins had been worked for 3 to 4 weeks and obtained a count of 50,000 bacteria per cubic centimeter of a type capable of developing in ordinary nutrient gelatin containing ammonia. They identified Micrococcus flavus liquefaciens and B. prodigiosus, both of which are known to produce proteolytic enzymes. The bacteria found on the roots of wool from the sweating process were found to be capable of growing in a liquid as alkaline as 0.05 normal. These appear to be similar to the bacteria commonly present in mellow lime liquors and Wood considers it highly probable that the unhairing action both in the sweat chamber and in mellow lime liquors is due to the same bacteria, not necessarily belonging to a single species.
Stiasny * also showed that bacteria play an important role in old lime liquors. An untreated mellow lime liquor caused a loosening of the hair of calf skin in 24 hours, but in a test where chloroform was added to the same liquor to check bacterial action the liquor was not able to cause any loosening of the hair in 3 days. A portion of the untreated liquor was freed from ammonia by heating to 60° C. and passing carbon dioxide-free air through it for 4 hours. It then showed an unhairing power as great as before, but a lesser solvent action on the hide substance, indicating that the unhairing action is due to bacterial action rather than to the ammonia ordinarily present in mellow liquors.
Since sterile lime water appears to have but little unhairing action on skins, it was long thought that bacteria were necessary for this action, where no sharpening agent was employed. But Schlichte ® found that skin previously sterilized by the Seymour-Jones process, with mercuric chloride and formic acid, could be unhaired easily after two weeks of contact with saturated lime water under sterile conditions. Wood and Law," however, pointed out that the action may have been influenced by the previous swelling of the skin in the sterilizing solution. This is intelligible from the viewpoint of Stiasny,‘ who regards proteins as peptones held together relatively loosely by means of secondary valency forces. The peptones are considered to be built up of peptides held together by forces of primary valence. He as-sumes that the swelling of a protein jelly causes a diminution in the forces holding the peptones together. On this basis, the swollen protein, or one in which the bonds between the peptones had been weakened through previous swelling, would be attacked by hydrolyzing agents much more readily than the unswollen protein. In support of this view, he finds that collagen is attacked by trypsin very much more rapidly when swollen by potassium thiocyanate or iodide solutions and that the action then goes only to the peptone stage.
hydrolyze proteins to a lesser extent than the hydroxides of sodium or ammonium because of the higher valency of the cations. The swelling of proteins in alkaline solution is due to the pull of the cations of the protein salt, which tend to diffuse from the region of high concentration of ions in the jelly to the region of lower concentration in the surrounding solution. If this pull is sufficiently great, we might reasonably expect a breaking up of the units making up the protein jelly. A sodium or ammonium ion exerts its entire pull upon a single unit, whereas the pull of a divalent cation is divided between two units, making the tendency towards decomposing the protein only half as great. This valency effect, however, is not the only one playing a part in sterile unhairing liquors because the mere replacement of half of the hydroxide ions of lime water by sulfhydrate ions is sufficient to cause a very marked increase in the rate of unhairing. Wood and Law suggested that Schlichte’s observation of the unhairing power of sterile lime water is further complicated by the formation of sulfur compounds by the action of lime on the easily dissolved sulfur of the hair. Such compounds are capable of loosening the hair.
Unhairing by Means of Other Alkalies.
Pure solutions of sodium hydroxide and sodium sulfide quickly destroy the hair and epidermis when sufficiently concentrated. A 2-per cent solution of Na,S at 25°C. will dissolve the hair and epidermis from the surface of a calf skin in about 2 hours, during which time only a comparatively small amount of collagen is destroyed. This treatment has been applied with considerable success to heavy hides, especially those which had previously been dried, and was a great help in speeding up the production of army leathers during the war. The hides were put into the sulfide solution, which was agitated by means of a paddle wheel. After several hours the hides were transferred to a solution of sodium bicarbonate or calcium chloride in order to stop the caustic action of the sodium sulfide. They were then washed and were ready for bating or tanning. The hair was completely dissolved from the surface of the hides in the sulfide liquor, but the action was so rapid that they had to be removed before the sulfide had diffused into them to the depth of the hair bulbs. As a result, the hair bulbs were usually left in the hides intact, as could be shown by examining sections under the microscope, but this apparently did not lower the value of the leather in any way.
With this method of unhairing, it was found economical to use the same liquor for a number of consecutive lots of skins, adding just enough fresh sodium sulfide each time to maintain the necessary concentration. The liquors soon became heavily charged with protein decomposition products which are soluble in alkaline solution, but are precipitated by rendering the solution faintly acid. Kadish and
Kadish ** made use of this fact in a scheme for recovering this nitrogenous matter as fertilizer. The waste liquors were run into a mixing chamber where they were reacted upon by sulfuric, sulfurous, or other acid. The precipitated nitrogenous matter was separated from the mother liquor and the hydrogen sulfide was recovered separately in such manner as to make the entire operation continuous.
Using sodium hydroxide instead of the sulfide, a similar unhairing action is obtained, but the skin becomes much more swollen and plumped. For the finer grades of light skins, where a smooth grain surface is required, neither sodium hydroxide nor sulfide solutions can be used alone because of the rough grain resulting from the excessive plumping.
It is not an uncommon practice in dewooling sheep skins to paint them on the flesh side with a paste made of a mixture of lime and sodium sulfide. The skins are then folded, wool side out, and left until the sulfide has diffused into the skins as far as the hair bulbs. When these are destroyed, the wool can be pulled or brushed out. As a rule, the skins are thrown over a beam and the wool is worked off by a beamster. The skins are then limed, washed, bated, and pickled, in which condition they may be kept until required for tanning. Sometimes the paste is made from lime and arsenic sulfide.
Solutions of ammonia in twice-molar concentration have a very marked unhairing action on fresh skins. The author found that fresh calf skins could be unhaired quite satisfactorily after only two hours’ immersion in such a solution. The skin swells but very little and the grain surface is left remarkably smooth and silky. If the skin is left in the solution longer than is necessary, however, there 1s danger of it suffering damage because of the powerful action of the ammonia on the collagen fibers. Since the unhairing’ powers of ammonia have long been known, it has often been wondered why its use has not become widespread. In an investigation, the author found that it could not be relied upon for unhairing the ordinary run of skins in commerce because its action is influenced by the previous treatment of the skin. On some skins, the ammonia would loosen the hair only in patches. In one experiment, a piece of fresh calf skin was cut into two pieces. One was put directly into twice-molar ammonia solution and the hair was loosened quite satisfactorily in two hours. The other was soaked in molar acetic acid for an hour, washed, neutralized with ammonia, and then put into the twice-normal ammonia solution. But there was no appreciable loosening of the hair after several hours.
Stiasny “* studied the effect of adding different salts upon the unhairing action of ammonia. He used a series of liquors each consisting of half-normal ammonia and 0.07 normal chloride of sodium, calcium, barium, or zinc. One liquor contained ammonia alone. A piece of fresh calf skin was put into each. After 2 days the piece in am-
monia alone had increased in weight 65.5 per cent, the one in the solution containing sodium chloride 45.8 per cent, in calcium chloride 14.9 per cent, in barium chloride 19.8 per cent, and in the solution containing zinc chloride 31.4 per cent. The hair was loosened in the solution of ammonia alone and in the one containing sodium chloride, but not in the others. Atkin’ has pointed out that the difference in repression: of swelling by the different salts may be attributed to the valency of the cation. It is, of course, evident that the difference in unhairing action may be explained in the same way. Stiasny, however, looked upon the difference in action as due to the formation of complexes between the ammonia and the divalent cations, giving salts of the type Ca(NH,),Ch.
In 1916, Mr. J. T. Wood sent the author a piece of calf skin which had been sterilized by the Seymour-Jones process. The formic acid had caused a loosening of the hair, which Mr. Wood says was marked in 8 days. Thuau*® and Nihoul !’ had previously shown that sulfurous acid will cause a loosening of the hair of skins, if used in solutions that will prevent the swelling of the skin, as in the presence of salt. Marriott’® found that salted hide could be unhaired by immersion in 0.25-per cent acetic acid solution for Q days.
In no case was the hair loosening by means of acid as satisfactory as can be obtained in alkaline solution. The acid seems to attack only the deepest layer of the epithelial cells of the Malpighian layer, leaving most of the epidermis intact, to be removed with the hair. It seems doubtful that acid will ever replace alkaline solutions for unhairing.
In 1913, Rohm ** described a process for unhairing and bating skins in one operation, involving the use of an alkaline solution of pancreatin. Since then pancreatin has often been listed as an unhairing agent. In 1920, Hollander *? described Réhm’s process as having a number of advantages over the old system of liming and claimed that it depends entirely upon enzyme action for unhairing. According to his description, the skins ‘are first soaked for 1 day in dilute sodium ‘hydroxide solution and then transferred to a dilute solution of sodium bicarbonate to which the enzyme is added after the swelling due to the alkali has been counteracted. Twenty-four hours later the hair is completely loosened and can be rubbed off.
determining the specific rdle played by the enzyme. They made a preliminary examination by soaking pieces of thoroughly cleansed calf skin in 0.05 molar sodium hydroxide solution for 1 day, replacing the solution next day by 0.1 molar sodium bicarbonate solution, and 5 hours later transferring the pieces to a solution made by diluting 18 cubic centimeters of molar sodium hydroxide, 2.8 grams of monosodium phosphate, and 1 gram of U.S.P. pancreatin to 1 liter. The pH value of the solution was found to be 7.52 at 25° C., lying well within the range of optimum activity of this enzyme. Two experiments were run at a temperature of 25° C., but in one the solutions were left exposed to air, as would be the case in practice, while in the other they were covered with a layer of toluene to check bacterial action. After the pieces had been in the enzyme solutions for 24 hours, the hair of the pieces from the solutions exposed to air could be rubbed off with the greatest ease, leaving the erain surface clean and white, but that of the pieces from the solutions under toluene remained firmly fixed. This seemed to indicate that the unhairing action obtained at 25° was not due to the enzyme, but probably to proteolytic bacteria or their products.
Because of the doubt thus cast upon the role played by pancreatin sn this method of unhairing, Wilson and Gallun carried the investigation further, paying particular attention to the action of pancreatin at 4o° C., the temperature of its maximum activity. The studies were made upon pieces of fresh calf skin, about 5 x3 inches, which had been thoroughly soaked and cleansed. Each experiment was carried out both at 25° and at 4o°C. The action of the enzyme solution upon the skin in each test was compared with the action of a blank identical with the enzyme solution except for the fact that it contained no enzyme. This solution was prepared by diluting 18 cubic centimeters of molar sodium hydroxide solution and 2.8 grams of monosodium phosphate to 1 liter and all enzyme solutions were made by adding to it 1 gram of pancreatin per liter. The pH values did not vary more than o.1 from the value 7.6 in any case. The enzyme solutions and blanks as well as solutions used for the pretreatment of the skin were all covered with a layer of toluene to check bacterial ‘action. The results were checked on separate occasions with pieces of skin from different sources.
The effect of pancreatin upon skin not previously soaked in sodium hydroxide solution, or any other swelling agent, was studied first. After 24 hours of contact of skin and solution, little action was noticeable either at 25° or 40°, but after 48 hours the collagen fibers of the skin in the enzyme solution at 40° began to dissolve very rapidly, the action proceeding from the flesh side, but there was no indication © of the hair becoming loosened. On the other hand, the skin in the blank at 40° and those at 25° in both blank and enzyme solution still remained but little affected. It was evident that pancreatin has a more powerful solvent action upon the collagen fibers than upon the epidermis of a skin not previously swollen with acid or alkali. The time factor involved in the destruction of the collagen fibers is in-
teresting. The action seemed to indicate that the fibers were coated with some material more resistant to tryptic digestion than the collagen beneath it. Possibly this supposed covering may be found to bear some relation to what Seymour-Jones 7? has called the fiber “sarcolemma.”’ |
In the next series of experiments, the pieces of skin were kept for 24 hours in 0.05 molar sodium hydroxide solution at 25° and 40° C., respectively. The solutions were then replaced by 0.1 molar sodium bicarbonate solutions of corresponding temperatures, and 5 hours later by the enzyme and blank solutions, in which the skins remained for 24 hours. The unhairing action in the enzyme solution at 40° was completely satisfactory, indicating that, at this temperature, pancreatin may be considered an unhairing agent for calf skin previously swollen in dilute sodium hydroxide solution. A very slight unhairing action was noticeable in the blank at 40°, evidently due to the previous treatment with alkali. No unhairing action could be detected in the blank or enzyme solution at 25°.
The preceding series of experiments was then repeated exactly, except that 0.05 molar hydrochloric acid solution was substituted for the alkali as the swelling agent. At 25° there was no visible unhairing action either in the blank or enzyme solution. In the hydrochloric acid solutions in the bath at 40°, the pieces of skin began to jelly; there was no further change in the piece transferred to the blank at 40°, but the piece put into the enzyme solution at 40° was quickly destroyed, the collagen passing into solution, leaving the epidermis and hair floating in the liquor. The opposite effects of acid and alkali upon the skin at 40° is interesting. 0.05 molar sodium hydroxide solution hydrolyzes the epidermis more rapidly than the collagen fibers, whereas 0.05 molar hydrochloric acid hydrolyzes collagen much more rapidly than it does the epidermis.
The experiment was repeated except for the fact that the pretreatment with hydrochloric acid was done at 25° and the digestion with pancreatin at 40°. After the skin had been in the pancreatin solution for 24 hours, the hair was completely loosened, showing that the effectiveness of pancreatin as an unhairing agent depends upon the previous swelling of the skin, but regardless of whether the swelling is caused by acid or alkali. The fact that pretreatment with sodium hydroxide in the experiment with alkalies was done at 40° did not seriously influence the result for, when another piece of skin was soaked in 0.05 molar sodium hydroxide solution at 25° for a day and then in the pancreatin solution at 40°, the unhairing action was entirely satisfactory.
pretreatment with ammonia, more at 40° than at 25°. After the pieces had been in the blank and enzyme solutions for 24 hours, they all showed some unhairing action, but in no case was it entirely satisfactory. The degree of action might be given a very rough rating by calling that in the enzyme solution at 40° 75 per cent, that in the blank at 40° 50 per cent, and that in both blank and enzyme solutions at 25° 25 per cent. Evidently the pretreatment of skin with ammonia, which is itself an unhairing agent, does not assist the unhairing action of pancreatin nearly so much as pretreatment with materials whose action is primarily to swell the skin.
Combined Bating and Unhairing by Means of Pancreatin.
Wilson and Gallun extended their investigation to an examination of the effect of the pancreatin upon the elastin fibers of the skin, the work of Wilson and Daub having indicated previously that the fundamental action of bating is the removal of elastin fibers from the skin. The work of Wilson and Daub will be described in the next chapter. Pieces of skin were taken from the various experiments after the pancreatin had acted upon them. These were imbedded, sectioned, stained, and mounted for examination, as described in Chapter 2.
When the pancreatin method of unhairing is used in practice, the liquors are left exposed to air. The experiments of Wilson and Gallun show that the hair loosening can then be effected at a temperature of 25°C., but that the action is apparently not due to enzyme, but rather to bacteria, since it is checked by covering the solutions with toluene. But, if pancreatin is not the active agent, we should expect the action not to be accompanied by elastin removal. Fig. 71 corroborates this view; where the hair loosening was effected by a pancreatin solution at 25°, exposed to air, the epidermis is disintegrated and the hair loosened, but the elastin fibers remain undissolved and show in the upper half of the picture as fine, black threads running nearly horizontally.
In the unhairing experiments where the skin from the enzyme solutions at 40° C. had not previously been swollen with acid or alkali, microscopic examination showed that all of the elastin had been dissolved away from the flesh side of the skin in 24 hours, but none from the region just under the epidermis. The hard corneous layer of the epidermis had apparently acted as a membrane impermeable to the enzyme. In the ordinary methods of unhairing, such as liming, the unhairing agent acts upon the cells of the Malpighian layer, which lie between the corneous layer and the derma. The impermeability of the corneous layer to the enzyme explains why the pancreatin did not attack the Malpighian layer and loosen the hair. In acid or alkaline solutions, the corneous layer swells considerably and is thereby rendered more permeable. It is also attacked by the enzyme, when in the swollen condition, as shown by the fact that no corneous layer could be found in the sections examined.
Fig. 72 shows a section of calf skin which had been soaked in sodium hydroxide solution previous to digestion with pancreatin at 40° C., under toluene. Not only is the epidermis destroyed and the hair loosened, but the skin is completely bated, as shown by the absence of elastin fibers.
An interesting attempt to unhair skins by means of enzymes naturally occurring in the skin is that of H. C. Ross.** A 1-per cent solution of ammonium hydroxide is used to inactivate the foreign enzymes, while the thrombase found in the skins is activated by the addition of calcium lactate or polysulfide. It is mentioned that the thrombase may be assisted by the addition of trypsin or other proteolytic enzymes which will work in an alkaline medium. The unhairing is effected without destroying the epidermis, so that large sections thereof can be removed with the hair attached. Subsequent bating is unnecessary. In preparing dressing leathers, the solutions are heated, while for sole leathers cold liquids are employed, these allowing plumpifg to take place to a greater extent. How nearly the actual mechanism of this method of unhairing is suggested by the description of the patent is open to question, but it would be interesting — to see a study made of it along lines similar to those of the experiments of Wilson and Gallun.
Skins prepared for unhairing and scudding by means of pancreatin solutions are unhaired on a machine, scudded on the beam, and then washed, after which they are ready for tanning without further treatment. Skins from lime liquors are unhaired, scudded, washed and then either bated, delimed, drenched, or pickled before tanning. Some tanners put the skins directly into old vegetable tan liquors without giving them one of these treatments, but the tan liquor then becomes a deliming agent and has little value other than that of removing lime.
Apparently anything that will hydrolyze the newly formed cells of the epidermis without injuring the rest of the skin is a satisfactory unhairing agent. Lime owes its popularity to the safety attending its use. Its limited solubility makes it possible to maintain a constant hydroxide-ion concentration at about 0.03 mole per liter simply by using an excess. This concentration is high enough to retard putrefaction considerably and yet not great enough to injure the skin itself, since the solute is a diacid base. It is entirely possible, however, that the popularity of lime will wane when some of the newer methods of unhairing reach a higher stage of development.
Perhaps the most curious of all the processes involved in making leather is that of bating. Little is known of its origin because it WaSea secret process, but: it is at least some centuries old. After the skins are taken from the lime liquors, unhaired, scudded, and washed, they still contain lime in the form of carbonate and in combination with the skin proteins. At this stage they are plump and rubbery and tanners have experienced many difficulties due to putting the stock directly into certain types of vegetable tan liquors when it was in this condition. The object of bating is to prepare the unhaired skins for tanning and originally consisted in keeping. them in a warm infusion of the dung of dogs or fowls until all plumpness had disappeared and the skins had become so soft as to retain the impression of thumb and finger when pinched and sufficiently porous to permit the passage of air under pressure. When hen or pigeon manure was used, the process was called bating, and when dog dung was used, it was called puering, but the term bating is now applied to the process generally, regardless of the materials used. The difference in terminology naturally disappeared with the advent of artificial bating materials.
A common method for treating light skins was to put them into a vat filled with a liquor containing about Io0 grams of dog dung per liter, kept at a temperature of 40° C. by means of steam. A paddle wheel kept the liquor and skins in motion. During the action, the skins gradually lost the plumpness acquired in the lime liquors and became soft and raggy. The completion of the process was determined by the attainment of a certain degree of flaccidity, which the workmen could judge only after long experience. Hen or pigeon manure was sometimes used for light skins, but was more commonly applied to heavy hides because it penetrates more rapidly than dog dung, due apparently to the fact that it contains also the urinary products, especially urea.
For many years this remained one of the mysterious processes of the tannery. It gave some tanners an improved product, which they could get in no other way known to them. But during the past thirty years there has been a persistent effort to determine the essential reactions of bating so that it might be carried out more reliably and with less offensive materials, or that it might be done away with
entirely by treating the skins differently at other stages. For example, it had been suggested that the only important function of the bate is the removal of the insoluble lime compounds from the skin before tanning. But this was contested by those who believed that merely removing the lime was not sufficient. They regarded bating as a process necessary for the removal of certain undesirable protein constituents of the skin. In order to settle this question, investigators have made extensive studies of dungs, and of the skins and liquors, both before and after the process. -
The greatest pioneer work in this field has been carried out by J. T. Wood, whose investigations, coupled with practical developments by O. Rohm and others, have led to the almost complete replacement of the obnoxious dungs by pancreatic enzymes. In his book, Wood ? says: ‘When learning the trade as an apprentice every fault in the leather was attributed to this part of the work, and the troubles and miseries of the ‘puer shop’ first caused me to take up the study of puering. I was determined to know the causes underlying the process. Puering is not only a filthy and disgusting operation, but is prejudicial to health, and in the nature of it is attended by more worry and trouble than all the rest of the processes in leather making put together.”
Wood found the mineral matter of dungs to consist chiefly of the sulfates, chlorides, carbonates, and phosphates of sodium, potassium, ammonium, and calcium, and some silica. The most important organic constituents seemed to be the bacteria, enzymes, cellulose materials, and fats. He found both peptic and tryptic enzymes, a rennin, an amylolytic enzyme, and a lipase. Since the bate liquor is usually faintly alkaline, it seemed likely that trypsin was active in the process and it was later shown that this enzyme does produce some of the effects of dung upon the skin. Wood also isolated from dog dung a species of B. coli which was found to yield an enzyme capable of acting upon the skin like trypsin.
Artificial bates are now to be found upon the market which contain pancreatin, ammonium chloride, and supposedly inert fillers and these have largely supplanted the dung bates formerly used. But materials other than those containing tryptic enzymes have also appeared on the market, as bates, to revive the old question as to the fundamental object to be attained by bating. These materials apparently give satisfactory results for some kinds of leather, even though some of them consist merely of carbohydrates, which yield organic acids by fermentation. The dung bates evidently had several different functions, but apparently all manufacturers of artificial bating materials did not concentrate their attentions upon the same functions. Numbers of preparations of quite different properties are sold as bating materials and this has served to aggravate the confusion as to what constitutes a bating material. The several purposes served by these materials will be considered separately.
The one property which all of the various types of bating materials have in common is that of reducing the degree of swelling of the protein constituents of the limed skin, which action is known to the trade as falling. Indeed it would have been practically impossible for any artificial preparation to pass as a bate that did not have this property, because the degree of flaccidity of the skin was the accepted measure of the nearness to completion of the bating process.
It will be apparent from the discussion of the swelling of protein jellies given in Chapter 5 that the degree of falling of a skin must be a function of hydrogen-ion concentration and also of the concentration of neutral salts.
Wilson and Gallun 2 measured the degree of plumping of calf skin as a function of pH value by means of their method, which is described in Chapter 8. Pieces of unhaired skin, each about 2 centimeters square, were cut from the butt of a calf skin so as to insure the greatest degree of uniformity of structure. These were freed from lime by washing in a 1I2-per cent solution of sodium chloride containing a small amount of hydrochloric acid, and then neutralized in cold, saturated sodium bicarbonate solution. They were then washed and bated by keeping at 40° C. for 24 hours in a solution containing 0.1 gram of U.S.P. pancreatin, 2.8 grams of monosodium phosphate, and 18 cubic centimeters of molar sodium hydroxide solution per liter, giving a pH value of 7.7. Microscopic examination showed that this procedure removed all of the elastin fibers. The pieces were then washed in cold, running tap water, having a pH value of 8, for 24 hours. They were then kept in distilled water in the refrigerator at 7° C. until used for the tests. The condition in which the skin existed in this state was taken as a standard, as it was found to be easily reproducible.
A series of 24 large reservoirs of test solutions was prepared, each having a final concentration of tenth-molar phosphoric acid plus the amount of sodium hydroxide required to give the desired pH value as determined by the hydrogen electrode. A range of pH values from 4 to II was covered.
In each test a piece of skin in standard condition was placed in the Randall and Stickney thickness gauge described in Chapter 8. The gauge reading in every case was taken exactly five minutes after dropping the plunger onto the piece of skin. This was called the initial gauge reading. The skin was then shaken with water to bring it back to its natural shape and then put into 200 cubic centimeters of standard buffer solution of the desired pH value and kept in a thermostat refrigerator at 7° C. so as to reduce to a minimum any tendency towards putrefaction. After 24 hours, each solution was replaced by fresh buffer solution. After 4 days more, there being
practically no change taking place in the pH values of the solutions, it was assumed that equilibrium was established and the pieces were removed and their thicknesses measured again. ‘The results are given in Table XVI. The ratio of the final to the initial gauge reading is a measure of the degree of plumping of the skin and this is plotted as a function of the pH value in Fig. 73.
The significance of these two points of minimum plumping has been discussed in Chapter 5. By comparing Fig. 73, with Fig. 45, it will be seen that the plumping of calf skin varies in much the same way as the swelling of gelatin with change of pH value. Apparently collagen undergoes a change of form, possibly an internal rearrangement, in passing from an acid to an alkaline solution and the two points of minimum represent the isoelectric points of the two forms.
The degree of plumping at any point between 4.5 and g.O is relatively so small that the skin would pass as completely bated, if judged solely by its fallen condition. Wood, who was probably the first to apply the hydrogen electrode to tannery liquors, observed that the pH value of fresh dung bate liquors varied from about 4.7 to 5.4, whereas the bating of a pack of skins raised it to points lying
BATING 177
between 6.4 and 8.4. In a lime liquor, which has a pH value of about 12.5, the skin is very plump and rubbery. But when it is brought into equilibrium with a liquor having a pH value lying between 4.5 and 9.0, it becomes fallen and flaccid.
The author has observed that when putrefaction starts in protein solutions the pH value of the solution generally tends to shift into the region 5.5 to 6.0, regardless of what it may have been in-
itially. The putrid dung bates would, therefore, tend to reduce the pH value of the limed skin from 12.5 to a value approaching 6. But the bate liquor contains phosphates, which act as buffers, and the full drop in pH value is prevented. The phosphate is thus a safeguard against putrefaction of the skin, which would be quickly damaged if the pH value were allowed to drop to the range of maximum rate of putrefaction,
Many so-called bating materials probably serve chiefly to reduce the pH value of limed skins to the region of minimum plumping. The value of this fallen condition is readily apparent for skins which are to be tanned in vegetable tan liquors. ‘Tannins diffuse only very slowly through swollen skin, but when the skin is in a fallen condition, the tarinins are enabled to diffuse rapidly into the spaces between the fibers, greatly hastening complete penetration. There is a fallacy in the assumption that plump leather can be produced only by putting skin into the tan liquors in a plump condition. The solidity of the resulting leather is determined more by the reaction of the liquor itself than by the degree of plumping of the skin when first put into the liquor. |
The manufacture of materials capable of bringing limed skin into the condition of minimum plumping is obviously a simple matter. It is only necessary to incorporate a buffer material with one which will tend to lower the pH value of the limed skin to a final value of about 8. Among the materials used for this purpose are boric acid, ammonium chloride, weak organic acids and materials yielding acids by fermentation, and acid sodium phosphate. The author observed five successive lots of skins pass through an artificial bate liquor containing sodium phosphate, which was entirely uncontrolled, and 0.5 was the greatest deviation in pH value from the normal value of 8.0 during the entire period of operation. Whére it is desired only to bring the skins into a fallen condition, the process can be carried out very effectively using only sodium phosphate and the occasional addition of hydrochloric acid to maintain a pH value of about 8.
Although the degree of plumping of a skin is a function of the hydrogen-ion concentration, the action of a bate liquor in lowering the pH value of limed skin has an importance independent of the question of plumping. Nearly 80 per cent of the bated weight of a skin is due to water, or rather bate liquor. Even though the skin may be washed, the water will assume a pH value depending upon the substances held in combination with the skin. This adhering solution will therefore have an effect upon the tan liquor into which the skins are put. If the pH value of this adhering solution is very variable, difficulty will be experienced in vegetable tanning because the rate of tanning, the rate of diffusion of the tan. liquor into the skin, the color value of the tan liquor, and its tendency to oxidize are all functions of the pH value. Keeping constant the pH value of the solution adhering to the skins entering the tan liquors is a factor of great importance and one which made the old dung bates almost a necessity to the tanner who had no other way of controlling the pH value. The actual pH value, within limits, was probably of less importance than keeping it constant at some arbitrary value, which could be met by establishing conditions in the tan yard to correspond.
Many persons have looked upon bating chiefly as a process for removing the combined lime from the skins. In using a dung bate, Wood found from 3 to 6 per cent of lime, calculated as calcium oxide on the dry skin, before bating and only from 0.5 to 0.9 per cent after bating and all of this appeared to be present as neutral salt.
Artificial bates, however, do not all have the property of removing calcium from the skin. Upon investigating the operation of a bate liquor containing phosphates and ammonium chloride and having a pH value of 8.4, the author found no diminution of the calcium content of the skin during bating, although the skins had become completely fallen and practically all of the lime had been converted into neutral or insoluble salts. Apparently insoluble calcium phosphate had formed in the skin, where it remained. In cases like this, the process can hardly be called efficient as a means of deliming. Where nearly complete removal of calcium compounds is essential for the best operation of later processes, it is much better to employ a properly controlled acid liquor, such as those to be described in the next chapter.
Bacterial Action.
Bacteria play an important role in the action of dung bates, being instrumental in the removal of lime from the skin as well as in lowering the pH value to the region of minimum plumping. Some of the bacteria, or their products, also attack portions of the skin itself, as shown by the appearance of nitrogenous matter in solution. In Fig, 74 is shown a typical plate culture on gelatin? of a dung bate liquor in actual use.
Becker * isolated 54 varieties of bacteria from dog dung and studied the actions of many of them upon skin. He found one, which he called B. erodiens, capable of producing a falling action of limed skin similar to that of the dung bate itself. An artificial bacterial bate was developed independently by Wood in England and by G. Popp and H. Becker in Germany, but they later joined forces and _ perfected the artificial bate known as erodin, which consists of a nutrient material to which a pure culture of B. erodiens is added before using. This material has been used on a commercial scale and found to be a satisfactory substitute for dung for some kinds of leather.
Since B. erodiens does not secrete tryptic enzymes, Wood has suggested adding to it bacteria obtained from the roots of wool in the sweating process which secrete a mild form of proteolytic ferment. The susceptibility of erodin liquors to become contaminated by foreign bacteria presents an obstacle to any very widespread increase in their use. In using erodin, Wood has observed that the fresh liquor
during the bating operation.
Cruess and Wilson ® isolated 10 varieties of bacteria from pigeon dung and found that the falling of limed skins could be brought about by pure cultures in dilute skim milk. If the bating operation were unduly prolonged, the skin proteins became hydrolyzed, but they found
that danger from this source could be greatly minimized. by using a liquor containing 0.5 per cent of glucose. They pointed out that the glucose was decomposed into acids which checked bacterial action and assisted in the removal of lime from the skin.
The prevailing opinion is that bating is not produced directly by the bacteria, but rather by the products which they secrete. Of these, the enzymes are regarded as the most important because the reduction in pH value of the skin, with consequent falling, can be brought about by simple chemical means not generally regarded as constituting the process of bating. |
Enzyme Action and Elastin Removal.
Wood * separated the enzymes from dog dung by precipitation from solution with alcohol and showed that the enzymes, in conjunction with ammonium compounds, were capable of bating skins. In view of the fact that the bate liquor was alkaline, it seemed pretty certain that trypsin must be the principal enzyme acting. Wood and Law’ later showed that there were at least five different enzymes present in dog dung, as follows:
Where a skin contains an abundance of fat cells, the lipase probably
exerts an important function in hydrolyzing and emulsifying the fats. In 1908 Rohm ® patented the use of the enzymes of the pancreatic juice and ammonium salts as a bating material. This mixture now known as oropon has come into wide use and has largely supplanted the dung bates formerly used.
Recently there has been a concerted effort to determine just what part is played by pancreatin in the bating process. As a measure of the elastin content of skin, Rosenthal ® used the per cent of nitrogenous matter that could be rendered soluble by tryptic digestion. By this method he found that bating with oropon reduced the elastin content of calf skin from 10.36 to 0.31 per cent, calculated on the dry basis. The author’s later investigations of the bating process by means of the microscope, however, indicate that Rosenthal’s method of determining the elastin content of skin is unreliable. Apparently a large portion of the matter included as elastin was derived from the other protein constituents of the skin or their hydrolytic products.
Upon examining a dung bate liquor used to bate sheep grains, Wood found that nitrogenous matter had been dissolved equivalent to only one per cent of the total protein matter of the skins. As nearly as can be judged from microscopic observations, this represents approximately the percentage of elastin present in the skin.
Seymour-Jones *° also suggested that the function of bating is the removal of the elastin fibers of the skin. In collaboration with J. T. Wood, Seymour-Jones carried out an interesting experiment on the bating of sheep skin. The “flywing” grain of a sheep skin was split from the main body of the skin, called simply flesh for convenience,
and both grain and flesh were cut into halves along the backbone. One grain and one flesh were bated with pancreol, a pancreatin preparation similar to oropon, while the other halves were delimed with acetic acid, but not bated. All four pieces were then tanned with sumac. There was comparatively little difference between the bated and unbated flesh halves, but the grain samples were very different from each other. The bated grain was soft and even, with the hair-holes clean and clear, but in the unbated grain the hair-holes appeared to be glued up and the surface had a rough, contracted appearance. He concluded that elastin present in the region of the grain membrane must be digested. before tanning in order to produce a satisfactory grain surface, but that the bating of the skin under the grain is not only unnecessary, but often undesirable.
The difference which Seymour-Jones found between the two grains was probably not due entirely to the bating process, since one was treated with acetic acid while the other was not. This means that the unbated grain would be subjected to the action of tan liquor at a lower pH value than the bated grain. But as the pH value of a fresh tan liquor is lowered, there is an increasing tendency for it to produce in the grain layer of a skin the rhythmic swelling described in Chapter 5. This shows itself first in a roughening of the grain, similar to that described by Seymour-Jones, and with further drop in pH value the corrugation of the surface appears. The roughening of the grain which had not been bated may have been aggravated by the © presence of the elastin fibers, but the chief cause was probably the lower pH value.
Wilson and Daub *: ?? undertook to settle definitely the question of the removal of elastin in the bating process by means of the microscope. They prepared sections of calf skin taken both before and after bating with a solution of pancreatin and found that the process removes all of the elastin fibers, if sufficiently prolonged. Fig. 75 shows a section of calf skin taken after liming, unhairing, scudding, and washing, but before bating. The elastin fibers show as a thick, black band just under the grain surface; the magnification here is not sufficiently great to show each individual fiber. Another layer of elastin fibers — appears at the flesh boundary. The main body of the skin contains no elastin fibers excepting those surrounding blood vessels, nerves, and muscles. Fig. 76 shows an adjoining section of the same skin taken after bating for 24 hours in 0.oI-per cent pancreatin solution at 40° C., having a pH value of 7.5.
The author has recently received a letter from Mr. L. Krall of Geneva, Switzerland, claiming priority in discovering, by means of the microscope, that the chief function of bating is the removal of elastin fibers from the skin. His experiments, performed at the University of Geneva from 1914 to 1916, proved that the elastin fibers of skin can be entirely removed by digestion in an infusion of dog dung at 40°C. His photomicrographs show that the action of dung is
practically identical with that found by Wilson and Daub for pancreatin, thus furnishing further evidence of the soundness of Wood’s conclusion that pancreatin is the active constituent of dung in bating. Krall’s important paper ‘* was unfortunately buried in a private bulletin.
After examining hundreds of sections of skin, taken before and after bating, at high magnifications and with the employment of a great variety of stains, Wilson and Daub came to the conclusion that the removal of elastin is the primary function of bating and that the other actions associated with dung bates can all be produced by the simple chemical control of the processes other than bating. The falling of the skin, however, always accompanies the removal of elastin because the range of pH values over which pancreatin acts upon elastin is such as to reduce the plumping of limed skin to the point accepted as a measure of the completion of the bating process.
In studying the progress of bating, Wilson and Daub observed cross sections of skin taken before and after bating and estimated the per cent of elastin removed by the treatment. For this purpose, the sections were prepared and stained as described in Chapter 2. The enzyme which they employed was a commercial sample of U.S.P. pancreatin which showed by analysis: water, 6.3 per cent; ash, 6.8 per cent; nitrogen, 11.0 per cent; chlorine, 1.7 per cent; phosphates,
for determining tryptic activity described by Sherman and Neun,’* 10 milligrams of the sample acting upon I gram of casein in 100 cubic centimeters of solution for 1 hour at 40° C. and at pH value of 7.33 digested 51 milligrams of nitrogen, As a matter of caution, it should be pointed out that this does not give a correct measure of the activity of the enzyme so far as its power to digest elastin is concerned. The author suggests that the elastin-digesting power of a bating material be determined solely by the amount of elastin which a given sample can digest from skin under rigidly defined conditions. The activity of the sample on casein or gelatin may be entirely misleading as regards its value as a bating material.
For each series of experiments, Wilson and Daub cut a piece of limed and unhaired calf skin into strips about 2x0.5 inches. There is a small, but appreciable, difference in time required for complete removal of elastin from skins of different thickness and for this reason care was exercised in selecting all strips for any one series from the same part of the same skin, so as to have them all as nearly identical as possible. Each strip was put into 500 cubic centimeters of liquor, a volume large enough to prevent the skin from seriously altering the concentration of the liquor. The liquors were all put into dark brown bottles to shield them from the light and were kept in a large Freas thermostat for the stated lengths of time at 40° + 0.01° C., the optimum temperature for most enzyme actions.*°
18 Ferments in the Tannery. L. Krall. Societe Anonyme, anc. B. Siegfried. Zofingue, Switzerland. Private bulletin, June, 1918. 14H. C. Sherman and D. E. Neun. J. Am. Chem, Soc. 38 (1916), 2199. < The Chemistry of Enzyme Actions. K. G. Falk. The Chemical Catalog Co., New ork,
Every liquor contained 0.02 mole per liter of added phosphoric acid to act as a buffer, in addition to the enzyme, and the potassium hydroxide required to give the desired hydrogen-ion concentration. The pH value of each liquor was determined both before and after the digestion period by means of Hildebrand electrodes and a Leeds and Northrup potentiometer, excepting where it was proved by previous test that the results obtained by the Clark and Lubs series of indicators were sufficiently accurate. Except for the more strongly acid and alkaline solutions, the change in pH value during digestion was practically negligible. Estimates of the per cent of elastin removed were made on the basis of removal from the grain layer only. In some cases all of the elastin was removed from the grain layer before half of it was removed from the flesh layer. Since the shaving operation removes practically all of the flesh elastin, its removal in bating is of little importance,
As a rule, a preliminary series covering a very wide range was run, followed by a second series covering only the active range of the enzyme. A third series was usually run as a check.
It is well known that the hydrogen-ion concentration is an important factor in determining the rate of digestion by enzymes. Using 0.1 gram of pancreatin per liter and digesting for 24 hours, complete removal of elastin from the skin was obtained only between the pH values 7.5 and 8.5. <A portion of the pancreatin was put into a collodion sac and dialyzed against running tap water in a dark room for 16 hours and used in a duplicate series in such quantity as to represent 0.1 gram per liter of the original pancreatin. The results were identical with those obtained with the undialyzed enzyme. A series was then run in which the concentration of pancreatin was increased to 1.0 gram per liter. Complete removal of elastin was obtained between the pH values 5.5 and 8.5. The results of the two series, which are shown in Fig. 77, were carefully checked to insure their accuracy. The per. cent of the total elastin which was removed js plotted against the pH value of the solution taken after digestion and cooling to Bis ;
The peculiar relation of the curves to each other is significant. They nearly coincide at all pH values above 7.5, but at 6.0 the stronger solution is still at its optimum activity, while the weaker one has apparently entirely lost its elastin-digesting power. When an enzyme has been found to have different optimum pH values with different substrates, it has been supposed that the effect of the hydrogen-ion concentration upon the substrate has been the determining factor. But here we have the same enzyme and the same substrate, with a change in the optimum range due merely to a change in concentration of the enzyme.
An explanation is suggested by the work of Northrop,’® ’” who has shown that the activity of an enzyme solution is not necessarily a function of the apparent total enzyme concentration, but that a portion of the enzyme may be inactivated by combining with peptone or other foreign matter. He has pointed out further that the extent of the formation of addition compounds between protein and enzyme depends upon the concentration of protein ion, which in turn is a function
of the hydrogen-ion concentration. If some protein other than elastin is responsible for the inactivation of a portion of the enzyme, we should expect such action to be a minimum at the isoelectric point of this protein.
After bating, the strips of calf skin were all carefully examined for the “bated feel,’ which apparently bears no relation to elastin removal, but corresponds to a condition of minimum swelling of the skin proteins. The only strips passing this test were those from liquors having pH values between 6.1 and 9.8. The average of these is 8, which is also the midpoint of the optimum range for the more
ond point of minimum plumping of calf skin found by Wilson and Gallun and shown in Fig. 73. It is worthy of note that at 40° C. Wilson and Daub found no indication of a point of minimum except at 8. On the basis of the theory of the existence of two forms of collagen, discussed in Chapter 5, it would appear that at 40° Wilson and Daub were dealing only with the form stable at higher temperatures and pH values and whose isoelectric point appears to be at 7.7. The following explanation is therefore suggested tentatively. At a pH value of 7.7, practically all of the enzyme is left free to attack
the elastin, but as the pH value is decreased and the concentration of collagen cation correspondingly increased, more and more enzyme is removed from the field of action by combining with it. In the weaker enzyme solution at pH = 6 practically all of the enzyme is in combination with collagen, whereas in the stronger solution the excess of enzyme is still sufficient to digest elastin. It is interesting . also to note that Thomas and Seymour-Jones '* found that pancreatin attacks collagen at an increasing rate as the pH value is lowered irom 8 to 6. In dealing with the effect of hydrogen-ion concentration upon enzyme action, it is evidently necessary to know the effect of the
pik is interesting to compare the optimum pH values for tryptic digestion found by other investigators : 19 for albumose Michaelis and Davidsohn 20 found 7.7; for casein Sherman and Neun?! found 8.3, while Long and Hull *? found 5.5 to 6.3; and for fibrin Long and Hull 22 found 7.5 to 8.3. The total range of 5.5 to 8.3 corresponds closely to the range found by Wilson and Daub, 5.5 to 8.5, for complete removal of elastin by the more concentrated enzyme solution.
At pH values less than 3.0 there was a marked destruction of the collagen fibers, evidently due to acid hydrolysis, and the strips were much swollen and rubbery, but no removal of elastin could be detected.
pH value of each liquor was brought to 7.6 and this did not change during digestion. Each strip of calf skin was kept in a separate bottle. The bottles were removed from the thermostat at fixed intervals during 24 hours.
Complete removal of the elastin was effected by the stronger enzyme solution in 6 to 8 hours, but in the weaker solution 24 hours were required. The progress of the digestion is shown in Fig. 78. The time required to start the digestion, 2 hours for the stronger and 5 hours for the weaker solution, was apparently the time required for
Effect of Concentration of Enzyme.
Two identical series of solutions were prepared in which the individual members differed only in concentration of pancreatin. One series was kept in the thermostat for 5 hours and the other for 24 hours. The results are shown in F ig. 79 and furnish a study in economy, Complete removal of elastin is effected by 0.1 gram of pancreatin in 24 hours or by 1.1 grams in 5 hours,
A study of bating would not be complete if it did not include the effect of ammonium chloride, one of the most abundant constituents of commercial bating materials. Aside from its use as a filler, it has been assumed to be beneficial in removing lime from the skins and tending to maintain a slight alkalinity favorable to tryptic digestion. Two series of solutions were prepared in which the concentration of enzyme was 0.1 and 1.0 gram per liter, respectively. To each successive member of each series increasing amounts of ammonium chloride were added and the pH values of all members were brought to 7.6. The time of digestion was 24 hours. The results are shown in Fig. 80.
In working with very dilute enzyme solutions, a distinct activating effect was noted upon the addition of 0.5 gram per liter of ammonium chloride, while larger amounts showed an inhibitory effect. With thin calf skin the activating effect was not detectable with the solution containing 0.1 gram per liter of enzyme after a 24-hour digestion period, because all of the elastin was removed without adding any ammonium chloride. In order to show the activating effect in these experiments, strips from heavier skins were used, which require a somewhat longer time for complete removal of elastin under
enzyme. ,
This behavior of ammonium chloride is interesting in view of the finding of Thomas ?* that potassium bromide in concentrations of 0.0 to 0.1 mole per liter has an inhibitory effect upon the action of malt amylase, but in greater concentration has an activating effect.
At concentrations greater than 50 grams per liter the ammonium chloride exerted a destructive action upon the collagen fibers, probably due to the formation of free ammonia.
Distribution of Elastin Fibers in the Skins of Different Animals.
It is well appreciated by tanners that skins of different animals and of animals of different ages must be treated differently in bating, as well as in other processes. It has been noted, for example, that the bating of a cow hide is less effective than the bating of a calf skin under the same conditions. The reason for this will be made apparent by comparing Figs. 81 and 82, both of which were photographed at exactly the same magnification. They represent the upper portions of the skins taken after liming, unhairing, scudding, and washing, but before bating. Fig. 81 is from a full grown cow hide,
while Fig. 82 is from a young heifer calf skin. It will be noted that the older skin has relatively fewer elastin fibers, although they extend into the skin to a greater absolute depth. This greater depth necessitates leaving the hide in the bate liquor for a longer time, so that the enzyme may diffuse to the most deeply seated fibers, but, on the other hand, there is less reason for removing the elastin fibers from the heavier skin, because they are relatively fewer. : Fig. 83 shows the elastin fibers of a sheep skin before bating and Fig. 84 those of a hog skin. The elastin fibers of the hog skin are very sparsely. scattered; the heavy band of elastin fibers passing obliquely upward to the right, across the center, is apparently there for the purpose of protecting the erector pili muscle, which it surrounds. Figs. 81, 82, 83, and 84 should be compared with Figs. 11, 18, 28, and 30, respectively, of Chapter 2, which show sections taken from the same skins when fresh.
Effect of Elastin Removal on the Final Leather.
Wilson and Daub attempted to determine the practical value of bating by comparing bated and unbated skins. A limed calf skin was cut into halves along the line of the backbone, the elastin was completely removed from one half by means of pancreatin, while the other half was simply treated with dilute ammonium chloride solution having a pH value of 8, in order to reduce its degree of plumping to that corresponding to what is accepted as the bated state. Both halves were then thoroughly washed. It was recognized that an exact comparison of the two halves during tanning could not be made, if the pH values of the absorbed solutions were very different. Every effort was made to have the pieces identical, excepting for elastin content.
The most noticeable difference was observed during the early stage of vegetable tanning. The surface layers of the skin naturally tan ‘ more rapidly than the fibers in the interior and there is a tendency for the grain surface to expand temporarily to a greater extent than the rest of the skin. The elastin fibers in the unbated half evidently tended to prevent this expansion and the result of the tension produced was a slightly harsh feel, although the grain appeared tight and smooth to the eye. The grain of the completely bated half, however, actually expanded, giving the skin temporarily a wrinkled appearance, although the grain felt very soft and silky. When both halves had become completely tanned, this difference had almost disappeared. In the finished leather, the only difference in appearance was a slightly lighter color in the bated half. Photomicrographs of exactly corresponding points on the grain surface of the two halves are shown in Fig. 85. The difference in appearance of the grain surface in the two cases is practically negligible. In carrying out practical tests of this kind, tanners usually fail to appreciate the importance of having the test pieces in equilibrium with solutions of
While bated and unbated finished leathers appear much alike to the eye, there are perceptible physical differences, such as one might expect to find in view of the fact that the elastin fibers have been removed from under the grain of the bated leather. The desirability of completely, or even partially, removing elastin from skin depends upon the use to which the leather is to be put. Bated leathers are
usually a little softer than unbated leathers, but this is desirable for some leathers and undesirable for others. Wood ** believes that. it is not necessary, or even desirable, to remove all of the elastin in bating, but that it is sufficient for the elastin fibers to be broken up or weakened, in order that the desired suppleness may be obtained.
Digestion of Collagen during Bating.
Although Thomas and Seymour-Jones have shown that pancreatin hydrolyzes collagen, the work of Wilson and Daub indicates that no serious loss of collagen occurs where the pH value is kept within the limits 7.5 to 8.0 and the action is stopped just as soon as all of the elastin fibers have been dissolved. Unduly prolonging the bating operation is sure to result in a very considerable hydrolysis of collagen, with corresponding decreases in the yield and firmness of the leather. Often an apparently heavy loss of collagen during
bating may be attributed to a previous breaking down of the collagen by excessive liming, putrefaction, or contact with liquors containing much ammonia. Manufacturers of glove leather sometimes make use of these agencies in order to get a very soft leather. They leave the skins in the lime liquor until a considerable amount of hydrolysis of collagen has taken place and then subject the skins to a prolonged bating. Much valuable collagen is thus lost, but the skins are thereby rendered more suitable for a specific purpose.
Drenching and Pickling.
In the final preparation of the skin for tanning, the pH value of the solution absorbed by the skin and with which the skin is in equilibrium must be adjusted to suit the particular method of tanning to be employed. During liming, this solution has a pH value of about 12.5; during bating, a pH value of about 7.5. Before skins can be tanned properly by any of the common methods of tanning, the pH value of this solution must be lowered considerably below the value 7-5. During vegetable tanning, the pH value of the liquor is usually less than 5 and in chrome tanning less than 4. By using tan liquors containing the proper excess of acid, the adjustment of pH value may be made in the tan liquor itself. But this is often a very difficult matter where the process is not under rigid chemical control.
For certain classes of leather, it is customary to subject the bated skins, before tanning, to a process known as drenching. Sometimes the bating process is omitted, as entirely unnecessary, and the skins are drenched directly after the washing following the unhairing process. The drench liquor is prepared by mixing 5 to 10 grams of bran per liter of water at 30° to 35° C. and allowing the mixture to ferment, with the formation of organic acids. The skins are put into this liquor contained in a vat equipped with a paddle wheel which keeps the liquor well stirred. In some tanneries, the fermentation is carried out in special tanks and only the clear, decanted, acid solution used on the skins. The acid: dissolves any lime remaining in the skin and brings the skin into a more suitable condition for tanning. The particles of bran also exert a sort of cleansing action upon the skin, tending to absorb dirt and greases. The treatment is usually continued for several hours, but the completion of the process is determined by skilled workmen, who have learned to judge by the feel and appearance of the skin just when it is ready for the particular tanning process to be employed. |
During the process, there is a considerable evolution of gas, which tends to cause the skins to float to the surface. In a drench in actual use, Wood * found that the gases had the following composition:
drenching, trimethylamine being the chief.
It was found that the starch of the bran is converted into glucoses and dextrin by the action of an amylolytic enzyme, cerealin, discovered by Mege Mouries.? It resembles the diastase of translocation described by Brown and Morris? in their work on the germination of grass seeds. It transforms starch into dextrin and glucose, whereas ordinary malt diastase transforms starch into dextrin and maltose. The action of cerealin is much slower than that of diastase. The sugars are then fermented by bacteria (Bacillus furfuris) with the formation of the organic acids listed above. The principal acid produced is lactic; the acetic acid is produced directly from the glucoses without any preliminary alcoholic fermentation by yeasts.
In the hands of experienced operators, the drenching process seldom gives much trouble, but it is not quite foolproof. If the acidity of the liquor increases rapidly and the skins are not removed in time, they become excessively swollen and may even be destroyed by hydrolysis, especially if the liquor is very warm. How much enzymes play a part in this hydrolysis is not yet known. Apparently danger from this source can be prevented by adding salt to the liquor to repress ‘the swelling of the skin just as soon as it becomes very noticeable.
In his review of the damage to skins that may be caused by improper control of the drenching operation, Wood * points out that the discovery of the effectiveness of salt in preventing the destruction of skin in an acid liquor that would otherwise cause excessive swelling represents the origin of the modern pickling process.
Sometimes the fermentation may not proceed in the usual manner and the liquor, instead of becoming acid, turns slightly alkaline, frequently becoming bluish black, due to the presence of chromogenic bacteria. Under these conditions the skin is rapidly attacked by proteolytic organisms, but may be saved if transferred in time to a solution of acid and salt.
of gas, the skins may be damaged by the formation of gases inside of the skin which burst out through the grain surface, leaving small holes. A damage very similar in appearance may be caused by proteolytic bacteria developing on the grain surface, each colony forming a small hole. This usually results from operating the drench at too high a temperature. A high temperature, especially in the presence of an excess of acid over that normally present, may result in a considerable amount of hydrolysis of collagen and the leather will feel rather spongy and empty.
When bacteria attack the grain during drenching, the surface of the finished leather may show dull patches, as though it were etched. In one instance, Eitner® found that this was caused by Bacillus megaterium, which formed a slimy film over the grain surface, which was attacked by a proteolytic enzyme secreted by the bacillus.
Wood and Wilcox ® showed that if the acids ordinarily found in the drench are used in pure solution in the proportions in which they occur in the drench, the action upon the skin is the same, except for being more rapid. With the appreciation of the fact that the active constituent of the drench is the acid formed, tanners began to substitute pure solutions of organic acids, such as lactic and acetic. These could be used with safety, simply by adding the acid at such rate as to keep the solution just neutral to methyl orange. Hydrochloric acid, being cheaper, is often used, although it makes the control more delicate. In this way practically all of the lime can be removed from the skins and the skins then combine with a sufficient amount of the acid so that they do not reduce the acidity of the ordinary vegetable tan liquor into which they may be put.
But even when pure solutions of acid were employed to drench skins, no fixed rule could be made for all tanneries. If the vegetable tan liquors contained a considerable amount of salt and other soluble nontannins, the drench could be operated at a lower pH value with safety. Where fresh liquors of tanning materials containing a relatively small proportion of nontannin were used, there was danger of the skins being damaged by the rhythmic swelling described in Chapter 5, whenever the pH value of the drench fell below some fixed value, which depended upon the composition of the tan liquor employed. This trouble can be avoided by the addition of salt to the tan liquor, but the remedy may be almost as undesirable as the disease, since many tan liquors are precipitated by the addition of salt. In general, the purer the first tan liquor into which the skins are put after drenching, the more delicate must the control of the drenching operation be.
It sometimes happens that the tan liquors employed contain easily fermentable sugars, which are continually being converted into organic acids. In such cases, the use of a drench prior to tanning may be undesirable and even the bating operation may be unnecessary, where
the removal of elastin is not important. The tan liquor itself actually becomes a drench and the lime salts formed serve to prevent rhythmic swelling. Where the skins have been drenched prior to putting into the tan liquor, the acid present may prove excessive and the skins will be spoiled.
One tanner may employ a non-acid tan liquor preceded by a drench, another may use acid tan liquors and do away with the drenching operation, and yet both may produce the same kind of finished leather. But one would not dare to adopt only a part of the other’s methods, which might prove disastrous; he must adopt all or none. This will serve to explain why it is not possible to outline quantitatively a rigid system of bating, drenching, deliming, or any other process, so that it may be used in any tannery. All fundamental operations in any one tannery are interdependent and a change, even one for the better, in one operation might necessitate a corresponding change in nearly every other operation. |
The pickling operation differs from drenching chiefly in the fact that salt is used in conjunction with the acid. Formerly it was the customary practice to soak the limed or bated skins in a vat containing dilute sulfuric acid until they became somewhat swollen and then to transfer them to a saturated solution of sodium chloride, which repressed the swelling. Now it is more common to use the acid and salt in solution together, the preliminary swelling having been found unnecessary and sometimes undesirable. A satisfactory pickle liquor for most purposes consists merely of a molar solution of sodium chloride to which sulfuric acid is added in the desired amounts.
Pickle liquors are used for a number of different purposes, the .
chief of which are the preparation of skin for chrome tanning and the preservation of unhaired skins so that they may be kept for an indefinite period before tanning.
In preparing skins for chrome tanning, the concentration of acid most desirable to use depends upon the degree of basicity of the chrome liquor employed. The more concentrated the acid in the pickle liquor, the more quickly does the system tend to reach a condition approximating equilibrium. Furthermore, the more concentrated the acid solution absorbed by the skin, the more quickly will the chromium salts penetrate into the interior of the skin during the tannage. On the other hand, if the concentration of acid is too great, the rate of fixation of chromium by the skin will be reduced to an undesirable degree, unless the excess of acid is neutralized by the addition of sodium bicarbonate, borax, or other agent, during the tannage.
Pickling has the advantage over drenching that it is extremely easy to control chemically. If the concentration of salt is not allowed to fall below half-molar, the pickle liquor can be controlled by simple titrations, using methyl orange as indicator. Regardless of the variable amounts of lime which the skins may contain before pickling, they
can all be brought into a uniform condition simply by so regulating the concentration of acid that all skins finally reach equilibrium with solutions of the same concentration. When used in this way, the pickling process becomes a stabilizer of inestimable value in chrome tanning.
When the equilibriumi concentration of acid is maintained at 0.05 normal or greater, the pickling of light skins requires only a few hours, but for weaker solutions and for heavy hides, the stock must remain in the liquor over night. In acid solutions greater than 0.01 normal, there is practically no danger of the skins being attacked by bacteria. The salt present is sufficient to prevent undue swelling at any pH value so that the process may be considered entirely safe, if only ordinary care is used.
For preserving skins, after bating, it is sufficient to bring them into equilibrium with a solution containing I mole of sodium chloride and 0.01 mole of sulfuric acid per liter. The liquors may be used for several consecutive lots of skin as the calcium sulfate formed is soluble in acid solution. The skins are usually pickled in vats equipped with paddle wheels, which keep the skins and. liquor in motion, greatly hastening the attainment of equilibrium. After equilibrium has been established, the skins are withdrawn from the liquor and thrown over wooden horses to drain. They may then be kept in a damp condition for many months.
It is often desired to tan such skins later in vegetable tan liquors of such composition that they would be precipitated by the salt and acid present in the skins. In such cases, the skins are first depickled by soaking in paddle vats containing a solution of half-molar sodium chloride to which borax is added at such rate as to keep the solution neutral to methyl orange. When equilibrium has been established, the skins are transferred to a wash wheel and the salt washed out by means of running water. They are then ready for tanning. Depickling is unnecessary in the case of chrome tanning.
In the control of pickle liquors, it must not be assumed that the _ decrease in concentration of acid is caused only by its neutralization ' by lime. Two other factors contribute to the decrease. The bated skins usually contain about 80 per cent by weight of water, only 20 per cent representing collagen. Part of the decrease is caused by the dilution by this water. The author has found that 1 gram of collagen combines with approximately 0.00133 gram equivalent of acid. By making allowance for the decrease in concentration of acid caused by dilution and by combination with the collagen, the amount consumed in neutralizing lime can be roughly approximated.
Vegetable Tanning Materials.
It has been known since prehistoric times that raw skin is colored and rendered imputrescible by contact with aqueous solutions of materials obtained from many forms of plant life. The active principle, - which is widely distributed throughout the vegetable kingdom, is a class of complex organic compounds known as tannin. By vegetable tanning is meant the combination of tannin with the protein matter of skin to form leather.
Among the materials which have assumed commercial importance as a source of tannin for leather manufacture are barks, woods, leaves, twigs, fruits, pods, and roots. Tanning extracts obtained from different sources show very different properties, which is due in a large measure to the foreign matter extracted with the tannin.
Classification.
Many attempts have been made to classify tanning materials according to their behavior in tanning practice, but this varies so widely with the nature and proportions of foreign matters extracted with the tannin that attempts at classification on this basis have not yet resulted in any scheme of great practical value. The properties of a tanning extract depend more, in many cases, upon the method of extraction or the conditions under which it is used in the tannery than upon its source in nature. By suitably controlling the conditions of tanning, it has been found possible to get practically the same result from tanning materials otherwise exhibiting markedly different properties. |
The tannins themselves, however, seem to fall chemically into two general classes, which have been named pyrogallol and catechol from the fact that tanning materials usually yield the one or the other of these two substances upon dry distillation. Upon fusion with sodium hydroxide, the pyrogallol tannins yield sodium gallate while the catechol tannins yield sodium protocatechuate. The pyrogallol tannins contain about 52 per cent of carbon as against about 60 per cent in the case of the catechol tannins. The two classes exhibit a number of different properties by which they may be differentiated.
All tannins seem to possess in common the property of precipitating gelatin from solution and this is used as a test to indicate the presence of tannin in solution. ‘The reagent is made by dissolving 10
grams of gelatin and 100 grams of sodium chloride in 1 liter of water. One drop of the gelatin-salt reagent is added to 5 cubic centimeters of the solution suspected of containing tannin. Under ordinary conditions, a precipitate is formed if more than a trace of tannin is present. The sensitivity of this test and the conditions under which it may fail to operate will be discussed in Chapter 12.
When ferric salts are added to tannin solutions, a deep blue color is formed in the presence of pyrogallol tannins and a deep green in the presence of catechol tannins. All tannins are precipitated by lead acetate, but if the solution is first made approximately normal to acetic acid, the pyrogallol tannins only are precipitated by the addition of lead acetate, the catechol tannins remaining in solution. On the other hand, the catechol tannins are precipitated by the addition of an excess of bromine water, while the pyrogallol tannins remain in solution.
A common method for differentiating between pyrogallol tannins and those of the catechol group is to add 10 cubic centimeters of 40-per cent formaldehyde solution and 5 cubic centimeters of concentrated hydrochloric acid to 50 cubic centimeters of the tannin solution and to boil the mixture for half an hour in a flask fitted with a reflux condenser. Catechol tannins are completely precipitated by this treatment. The solution is cooled and filtered. To 10 cubic centimeters of the filtrate are added 5 grams of sodium acetate crystals and 1 cubic centimeter of a I-per cent iron alum solution. A strong bluish violet coloration will appear if pyrogallol tannins are present, but none if the original solution contained only catechol tannins.
The separation of the tannins into these two groups and the extensive studies made of the reactions of the many different kinds of tanning materials have furnished the basis for a scheme of qualitative recognition of vegetable tanning materials which is sometimes of value in detecting adulteration in commercial tanning extracts. One of the best of these qualitative schemes is that of Procter.*
When liquors containing pyrogallol tannins undergo fermentation in the tan yard, they usually deposit finely divided ellagic acid, which appears as sludge in the bottom of the vat or as bloom on the surface of the leather. Catechol tannins, on the other hand, yield a difficultly soluble material called reds, or phlobaphenes.
Only the more important raw materials will be mentioned here; for more comprehensive lists, the reader is referred to the standard work of Dekker 2 and to the books of Procter* and Harvey.* Among the barks used most widely as a source of tannin are those of the several varieties of oak. Oak bark is one of the few materials furnishing both pyrogallol and catechol tannins, although the latter predominate. Tan-
ning extracts obtained from oak bark have long been favorites for the production of leather where firmness and solidity are desired. Hemlock bark is used extensively in the United States for the manufacture of heavy leathers. Extracts made from the barks of the larch, spruce, and fir are used to a very considerable extent both in America and in Europe. The barks of the mimosa, or wattle, the mallet, and the several species of mangrove, which are grown in Australia and South Africa, are very rich in tannin. Babool bark is commonly used in India and willow and birch in Russia. The leather known as Russia calf was originally tanned with birch bark, to which it owed its characteristic odor. As a general rule, the tannins of the barks belong to the catechol group.
Among the woods, that of the quebracho, grown in South America, is probably richest in tannin, ‘The tannins of chestnut and oak woods find application in the manufacture of sole leather for blending with other materials. Quebracho tannin is of the catechol type, while that of chestnut and oak woods is of the pyrogallol type. The extract obtained from the cutch wood of India is widely used as a mordant jn the dyeing of leather, Recently an extract of the wood of the osage Orange tree has appeared on the market both as a natural dyestuff and as a tanning agent.
The most important extracts obtained from leaves and twigs are those of the gambier of India and the sumac of Sicily. The stoner belongs to the catechol and the latter to the pyrogallol group. Gambier is one of the mildest tanning materials known, a property which it apparently owes to the large amount of nontannins present in the extract. It is used as a mordant and, in mixtures with other materials, in the manufacture of light leathers. Sumac is commonly used to tan the grain splits of sheep skins for hat bands, etc., and as a mordant. It is rather easily decomposed by boiling water.
A variety of unripe nuts and pods form a much used source of tannin, usually of the pyrogallol type. These often contain easily fermentable sugars and, by their use in tanning, it is often possible to do away with the acid drench to which skins are sometimes subjected prior to tanning. The light colors obtained when using materials like these, which yield acids by fermentation, may be explained, in the light of recent Investigations, by the fact that the color of a tan liquor as well as that of the leather it produces becomes lighter the lower the PH value. The pods of the algarobilla and divi-divi, grown extensively in Central and South America, and the dried, unripe nuts of the myrobalan tree of India are used jn mixtures with other materials that do not yield acids so readily. In the preparation of some mixtures, valonia, from the acorn cups of the Turkish oak, is favored. Another easily fermentable tanning extract is obtained from the babool pods of India, which contain both pyrogallol and catechol tannins.
Among the roots used as a source of tanning extracts, those of the palmetto, grown in the United States, and the canaigre, grown in Mexico and Australia, are perhaps the most common. The latter is rich in catechol tannin and has a tendency to ferment rather easily.
Where there is no chemical control of the tan liquors, the selection of tanning materials must be governed by the nature of the operations preceding and following the tanning process, as well as by price and availability of the materials. While quebracho extract, for example, is an excellent tanning material, its pure solutions are hardly suitable for receiving consecutive lots of raw skin containing much lime. Their naturally low acidity would be quickly neutralized and the tannin would then be precipitated by the lime, or oxidized, and cease to tan properly. But this danger would be greatly lessened by the use of a mixture of tanning extracts containing acid-producing materials, like those in dividivi or myrobalans.
Leaching.
It is still common to find tanneries equipped to extract the tannin from the raw materials grown in neighboring districts, although the manufacture of tanning extracts has now become a separate industry, which has proved useful in making a greater variety of materials available to the individual tannery.
One of the oldest systems for leaching raw materials, and the one most commonly used in tanneries, is known as the open vat method. The bark, or other material, is broken into small pieces and then shredded in a bark mill. The leaching tanks are usually arranged in batteries of about eight and are fitted with perforated false bottoms on which the bark is placed. The bottom of each tank is fitted with a pipe through which liquor may be drawn off or pumped from one tank to another. When fresh bark is put into a given tank, liquor is run onto it which has been used to leach the bark in all of the seven other tanks. This strong liquor is finally drawn off and pumped into a storage tank. The bark is then leached with liquor which has passed through only six other tanks. The eighth leaching of this bark is made with fresh water, after which the bark is dumped and discarded.
Fresh water is used to leach only the most nearly exhausted bark. As the liquor becomes stronger in tannin, it is run onto fresher bark, and finally onto the previously unleached bark. As soon as each tank is dumped, it is again filled with fresh bark and becomes the head vat in the cycle, which is continuous. The object of this system of leaching is to get final liquors as concentrated as possible. In the tannery, the liquor in the storage tank is used as needed, but in the extract plant it is necessary to evaporate off most of the water so as to make its subsequent transportation practical.
The extraction of the raw material is often facilitated by the use of mechanical devices. Sometimes the leaching tanks are equipped with mechanical stirrers or with pipes for bubbling air up through the liquor. In another system, the tanks are replaced by revolving drums, used on the same principle as the open vats, the liquor being pumped from one drum to another. In still another system, the bark, or other material, is forced through a trough in one direction, by means of a screw conveyor, while water flows over the bark in the
opposite direction. At the point of entry of the fresh water, the bark is practically exhausted and is dumped onto a pile from which it is subsequently moved to the furnaces for fuel, or is disposed of in some other way. At the point of entry of the bark, the liquor is richest in tannin and is conducted to the storage tank.
In many extract plants, autoclaves are employed in order to leach the bark under pressure, which increases the yield obtained. The liquor is pumped from one autoclave to another, just as in the open vat system. In a system only recently devised, the raw materials are leached in autoclaves under a vacuum. ‘The advantage claimed for this is that the liquor may be kept boiling at a very low temperature, giving increased yields, but not at the expense of the quality of the extract. The relative merits of the pressure and vacuum systems will probably be brought out more clearly when they have been more thoroughly investigated.
The rate at which tannin can be extracted from the raw material increases with the temperature of the water used, but so also does the rate at which the dissolved matter decomposes. The variation of the ratio of these two rates with temperature determines the optimum temperature that it is desirable to employ and this is different for different materials. It is customary to extract the fresh material at a low temperature and to increase the temperature of extraction until the material is practically exhausted. In using the open vat system for ordinary barks, it is a good plan to have the fresh water at the boiling point and to allow its temperature to fall slowly to about 60° C. as it passes over fresher bark. The temperature of the liquors can be controlled by having suitable heating coils placed in the tanks just under the false bottoms. :
Effect of Hardness and Alkalinity of the Water.
When a very hard, alkaline water is used in leaching, the tannin yield is very low and the extract is dark in color and of poor quality. This has been the subject of numerous investigations, from which the general conclusion has been drawn that the use of a soft water in leaching is imperative. But the recent work of Wilson and Kern seems to indicate that the question of hardness of the water used is of less importance than the pH value of water and liquor.
Effect of pH Value on the Color of Tan Liquors.
Wilson and Kern ° made a special study of the effect of pH value on the color of gambier and quebracho liquors. Two tan liquors were prepared, one from gambier and the other from quebracho extract. To
each was added sufficient phosphoric acid to bring the pH value to 2. 5 as determined by the hydrogen electrode. The phosphoric acid was added to act as a buffer in preventing large changes in pH value upon long standing. To equal portions of each, sodium hydroxide was added to give series of tan liquors ranging in pH value from 3.0 to 12.0 and all having a tannin content of 1 per cent, as determined by the Wilson-Kern method, to be described in the next chapter. The gambier series varied in color from light straw at 3.0 to a very deep red at 12.0. The quebracho series was similar in color excepting that the liquors of lower pH value had a touch of violet. Either series suggested a standard series of colors such as is used in the indicator method of determining hydrogen-ion concentration, except for the fact that a light precipitate formed in all liquors having a pH value of 4.0 or less. The difference in color was evidently a true indicator effect, for any member of one series could be made to match any other member simply by bringing it to the same pH value. All members of either series appeared practically identical when brought to a pH value of 3.0. This complete reversibility of color change, however, was not found when liquors at higher pH values were allowed to stand long exposed to air.
Two complete series of each extract were poured into test tubes; the tubes of one series of each were tightly stoppered, while the others were left open to the air. Next day the liquors in the stoppered tubes showed practically no change, but the others had become darker in color, the more so the higher the pH value. When the liquors in a series not exposed to air were all brought to a pH value of 3.0, they all assumed practically the same color. But when those of a series that had been exposed to
value during the period of reoe tan liquor to form a precipitate when sacle to air; furthermore a pre- brought to a pH value of 3 varies cipitate settled out from those with its pH value during a period of whose pH values had been in the exposure to air. vicinity of 9. ;
This precipitate formation is very curious. A complete series of each extract was allowed to stand exposed to air in shallow dishes for 3 days; the liquors were then made up to original volume and poured
into 100-cubic centimeter graduate cylinders. Each was brought to a pH value of 3.0 by the addition of hydrochloric acid and allowed to stand over night. Next day the volume of precipitate from 100 cubic centimeters of original liquor was read from each cylinder. The results are shown in Fig. &6.
Keeping a solution of either extract exposed to air while its pH value is 9 causes it to yield an enormous precipitate when its pH value is subsequently brought to 3.0. But keeping it exposed to air when its pH value is greater than 10 apparently prevents its precipitation when brought to 3; all such liquors remained brilliantly clear. The addition of a great excess of acid, however, caused all liquors to precipitate, while any precipitate could be completely redissolved by th addition of sufficient alkali. |
Another interesting fact is that the liquors exposed to air when their pH values lay between 8 and 9 gave much trouble with the hydrogen electrode. After bubbling hydrogen through them for only a few minutes, the voltage would fall rapidly towards zero. Even when brought to a pH value of 3.0, the liquors still gave this trouble, making it necessary to check the results by means of indicators. No such trouble was encountered with liquors exposed to air at pH values below 7 or above 10. Apparently pH —9 is a critical point in the oxidation of tan liquors.
The curves in Fig. 86 show that this effect of oxidation is appreciable at all pH values from 6 to about 10. Most hard waters have pH values lying within this range and many of them have pH values higher than 8. :
Wilson and Kern ® also studied the effect of pH value on the precipitation of quebracho liquors. Four series of solutions of solid quebracho extract were prepared according to the official method of the American Leather Chemists Association,’ except for the additions of sulfuric acid, hydrochloric acid, sodium hydroxide, and calcium hydroxide, respectively, to the four series to produce approximately the desired pH value before making each solution up to the required volume. The pH values were finally determined at 20° C. by means of the hydrogen electrode and the solutions were analyzed according to the official method. The effect of the added acid of ne upon the per cent of insoluble matter found is shown in
ig. 87.
The solution receiving no addition of acid or alkali had a pH value of 4.60. As the pH value was lowered from this, by the addition of either sulfuric or hydrochloric acid, there was an increase in the per cent of insoluble matter found, sulfuric acid proving the more effective in causing precipitation. With increasing pH value, there
was first a decrease in the amount of insoluble matter and the unfiltered solution gradually became more nearly transparent. In the case of the liquors containing sodium hydroxide, this continued without a break, the liquor having a pH value of 11.35 being quite transparent. But at the neutral point, an abrupt change occurred in the solutions containing calcium hydroxide; with further rise in pH value, the tannin was precipitated in increasing amounts.
If these data may be applied
quantitatively to raw tanning materials in general, it is evident that the precipitation of tannin by lime may be prevented by keeping the pH value of water and liquor, during extraction, under 7. But to avoid appreciable oxidation effects, the material should not be ex-
as the optimum pH value for leach- pH Value of ‘Tan tiqnees ing, since, with decreasing values rie 98 pe ; 8 ' f Fic. 87.—Effect of pH value on per ere 1S an increasing amount o cent of insoluble matter in solution
Clarifying, Decolorizing and Drying.
In the manufacture of tanning extracts for sale, it is desirable that the extract should be clear, have a good color, and be dried to a degree sufficient to make handling and shipment easy. Clarification, which consists merely of the removal of finely divided matter in suspension, is effected by settling and decantation, by filter-pressing, or by centrifuging.
Where the extract manufacturer has carried the extraction of the raw material nearly to the limit, the extract is apt to have a dark color, which is-not desirable. This seems to be due to the extraction of foreign matters at the high temperatures used, or, in some cases to oxidation. A common method of clarifying and decolorizing some extracts is bymmeans of blood albumin. The tan liquor is treated with a solution of blood albumin and then heated to a temperature of 70° C., at which the albumin coagulates and carries down with it the suspended matters, some of the deeply colored bodies, and some tannin. The clear liquor is decanted off and the sludge is filter-pressed to re-
way, the color of the extract is greatly improved.
A number of other methods of decolorizing involve the treatment of the tan liquor with chemicals.. Sulfur dioxide and sodium bisulfite are often used. Some brightening of the color would naturally be expected from the lowering of the pH value of the liquor by sulfur dioxide, but the total effect seems to be more complex than this, | since some of the suspended and difficultly soluble matters are thereby rendered soluble. Apparently the reducing action of sulfur dioxide plays: aapart... 4
There are naturally numerous methods in use for drying extracts. Since high temperatures and contact with the air during drying are undesirable, much of the drying is done in specially constructed vacuum dryers. As these have been greatly improved, from time to time, it has become possible to dry extracts to greater extents without causing them to suffer any damage. Formerly it was customary to reduce the water content of most extracts only to from 50 to 60 per cent, but now it is not uncommon to find extracts on the market having a water content as low as Io per cent.
Some idea of the volume of literature which has appeared dealing with the composition of tanning materials may be gained from the bibliography, compiled by Dean,’ of the more important papers published prior to 1910, which lists 273 papers. It is remarkable that the greatest work on the organic chemistry of the tannins was accomplished by the same man who did most to elucidate the complex structure of the proteins, Emil Fischer. Among the numerous papers by Fischer and his coworkers, telling of their work which led to the discovery of the composition of tannin, may be mentioned one entitled “Synthesis of Depsides, Lichen-Substances and Tannins,” 2 which is something in the nature of a review. The tannin studied by Fischer was that obtained from nutgalls, the so-called gallotannic acid and purest form of pyrogallol tannin.
As early as 1852, Strecker * concluded that tannin was a compound of glucose and gallic acid. He was supported by the works of van Tieghem,* who found glucose among the hydrolytic products of tannin, and Pottevin,? who effected the hydrolysis with the enzyme of Aspergillus niger. But the variation in proportion of glucose found weakened the view, which gave way to that of Schiff,* who regarded tannin as digallic acid:
HO COOH.
Although Schiff’s formula for tannin was widely accepted, it was shown very definitely that digallic acid is not tannin. The formula showed no asymmetric carbon atom in the molecule to account for the optical activity of the natural tannin and it could not account for the high molecular weights observed. By observing the electrical conductivity, hight absorption, and behavior towards arsenic acid, Walden? showed that Schiff’s digallic acid is very different from natural tannin. » Fischer and Freudenberg * first set out to determine whether the
glucose found by Strecker was really a constituent or only a chance impurity of tannin. They started with the purest technical tannin available. Assuming that the tannin molecule had no carboxyl group, they proceeded to separate it from acid impurities by rendering its solution slightly alkaline and extracting it with ethyl acetate, a method discovered independently and published previously by Paniker and Stiasny.° As they had anticipated, the tannin dissolved in the ethyl acetate, leaving the sodium gallate in the aqueous solution. They accepted this as proof that the tannin possessed no free carboxyl group. Applying this method of purification to different kinds of commercial tannin, they obtained products that were practically identical.
After hydrolyzing the purified tannin with sulfuric acid, they found between 7 and 8 per cent of glucose. In the purest sample of tannin examined, they found one molecule of glucose combined with ten molecules of gallic acid. No phenolcarboxylic acid other than gallic could be found in tannin, even when the hydrolysis was effected by means of alkali. With excess of alkali and exclusion of air, large yields of alkali salt of gallic acid were obtained in relatively pure condition.
It appeared to Fischer that the surest way to prove his assumptions regarding the structure of tannin was to synthesize it. He started out with the idea that tannin contains no carboxyl and that, consequently, the gallic acid must all be bound as an ester, a condition that would be fulfilled by regarding tannin as an ester-like combination of one molecule of glucose with five molecules of digallic acid, after the manner of pentacetyl glucose.
The investigations of Fischer and his collaborators are so extensive as to require treatment in a separate volume and the reader is referred to the recent book by Freudenberg,’® who is continuing Fischer’s work on the tannins. Fischer ‘* succeeded in preparing penta-m-digalloylB-glucose, which was proved to be an isomer of the tannin from Chinese nutgalls. The formula for the so-called gallotannic acid may thus be written
THE TANNINS 215
Freudenberg has suggested a classification of the tannins more distinctive than the catechol-pyrogallol system mentioned in Chapter 11. He would divide them into two main classes, the first consisting of hydrolyzable tannins in which the benzene nuclei are united to larger complexes through oxygen atoms, and the second of condensed tannins, in which the nuclei are held together through carbon linkages. Where both kinds of compounds are present, as in ellagic acid, the classification is decided by the genetic connection with other tannins.
The first group embraces three classes: (1) depsides, esters of phenolycarboxylic acids with each other or with other oxyacids; (2) the tannin class, or esters of phenolcarboxylic acids with polyatomic alcohols and sugars; and (3) glucosides. The most important criterion of the first group is hydrolysis to simple components by enzymes, particularly tannase or emulsin. Freudenberg and Vollbrecht?? have recently discussed the isolation and determination of the activity of tannase, which is secreted by Aspergillus niger.
The second group of tannins are not decomposed to simple components by enzymes. They are generally, but not always, precipitable by bromine and condense to amorphous tannins, or reds, of high molecular weight, when treated with oxidizing agents or with strong acids. They are divided into two classes according to whether or not phloroglucin is present. With the exception of some simpler ketones, oxybenzophenones and oxyphenylstyrylketones, the catechins belong to the phloroglucin class, which include the tannins of quebracho and probably also those of oak bark.
That the reds, or phlobaphenes, precipitated by acid from solutions of quebracho and gambier extracts are oxidation products is indicated by the curves in Fig. 86, which show that the quantity of precipitate obtained is greatly increased by previous oxidation. The actual composition of the phlobaphenes is not yet known. The ellagic acid, or bloom, formed in solutions of tanning extracts of the pyrogallol group, is of very much simpler composition than the phlobaphenes. The formula
Practical Definition of Tannin.
The great classical work on the structure of the tannins is still too far from complete to enable one to apply organic chemistry to practical tanning, excepting, perhaps, in the study of the reactions
of particular groups present in the tannin molecules. The structures of the tannins of the catechol group are still entirely unknown. As in the case of the proteins, it has been found necessary to deal with the general properties of the tannins from the standpoint of physical rather than organic chemistry.
All tannins seem to have the property of precipitating gelatin from solution and of combining with the protein matter of hide. fibers, forming a compound resistant to washing. Any natural vegetable material having this property in aqueous solution has generally been accepted as tannin, and this has been made the basis for the various methods of determining tannin now in use. The portion of soluble matter which neither combines with collagen to form a compound resistant to washing nor precipitates gelatin from solution is known as nontannin, 5
In testing a solution for the presence of tannin, it is customary to add to it one drop of a solution made. by dissolving 10 grams of gelatin and 100 grams of sodium chloride in a liter of water, a precipitate or turbidity indicating the presence of tannin. This reaction has been the subject of numerous investigations for more than a century. Its sensitivity as a means of detecting tannin in solution has recently been studied by Thomas and Frieden.1* They found that the added gelatin is completely precipitated when the ratio of gelatin to tannin does not exceed 0.5; a great excess of gelatin prevents precipitation.
Thomas and Frieden studied the precipitation of tannin by gelatin at different pH values and concentrations of salt. Using a gelatin solution containing no salt, they obtained a maximum precipitation of gallotannic acid, in pure solution, at a pH value of 4.4; at pH values below 4 or above 5, the solutions became opalescent, but no precipitate formed. The effect of adding sodium chloride was to widen the range of pH value over which a precipitate was obtainable: it apparently had no effect upon the sensitivity of the test between the pH values 4 and 5. Using various commercial tanning extracts, they found that the optimum range for precipitation of tannin by gelatin varied from 3-5 to 4.5, quebracho, wattle, and hemlock precipitating most readily at pH values slightly above 4.0 and gambier, oak, and larch at values slightly below 4.0.
The limits of dilution at which tannin could be detected by means of the gelatin-salt reagent were found to depend upon the proximity of the solution to the optimum pH value for precipitation, which is different for each kind of extract, but apparently always lies between 3-5 and 4.5. At the optimum pH value, gambier, the least sensitive to the test, could be detected at a concentration of 1 part of tannin to I10,000 parts of water. Wattle, the other extreme, could be detected at a dilution of 1 to 200,000. When the commercial extracts
were simply diluted with distilled water, no attention being paid to the final pH values, the sensitivity of the tests was greatly decreased. ‘The least sensitive was then hemlock at 1 part in 6,500 and the most sensitive was gambier at I part in 30,000. They also found that the age of the gelatin-salt reagent has no effect on the sensitivity of the test, provided bacterial action is prevented by means of toluene.
Although a general discussion of analytic methods is outside the scope of this book, the question of determining tannin demands some attention here because of its importance in leather chemistry and the fact that the methods in common use do not determine the actual tannin content of tanning materials, but include as tannin a variable fraction of nontannin, which, in the extreme case of gambier, is twice as great as the tannin content itself.
For more than a century leather chemists have struggled with the question of determining tannin and numerous methods have been proposed. Of these, the only one which has really survived is that known as the hide powder method. But even this is used in different parts of the world with different modifications. For a review of the various methods proposed up to 1908, the reader is referred to Procter’s book.*® It will serve our purpose here to give an outline of the official method of the American Leather Chemists Association, which is similar in principle, although not in all details, to those employed in various parts of Europe.
“American Standard” hide powder is specially prepared by giving it a light tannage with chrome alum, washing it practically free from soluble matter, and squeezing it until it contains not less than 71 nor more than 74 per cent of water. The solution of tanning material for analysis must contain not less than 0.375 nor more than 0.425 gram of tannin per 100 cubic centimeters, as found by this method. To 200 cubic centimeters of this solution is added such an amount of the wet hide powder as contains not less than 12.2 nor more than 12.8 grams of dry hide powder and the whole is shaken for 10 minutes. The detannized solution is separated from the powder by squeezing through linen and is then filtered through paper, after the addition of kaolin, the solution being returned to the paper until the filtrate is quite clear. The amount of residue from an aliquot portion of this filtrate, after correcting for the water introduced by the hide powder, is taken as a measure of the nontannin in the original material. The difference between the total soluble matter and the nontannin is called
us here. 3
It will be apparent from the discussion of the equilibria of protein systems in Chapter 5 that the method involves two false assumptions: one that the hide powder combines only with tannin; the other that the solution absorbed by the collagen jelly has the same concentration as that in the surrounding solution. It may be mentioned that the former assumption introduces errors vastly greater than the latter. As long ago as 1903, Procter and Blockey 1” showed
75 43.7 56.3
that hide powder removes from solution considerable amounts of such nontannins as gallic acid, quinol, and catechol. Wilson and Kern 18 showed this even more strikingly by subjecting pure solutions of gallic acid to the A.L.C.A. method of tannin analysis. By varying the concentration or the proportion of hide powder, practically any results desired could be obtained. Tables XVII and XVIII show that the A.L.C.A. value for tannin decreases with increasing concentration of the solution and increases with the proportion of hide powder. Using a solution of I gram of gallic acid per liter, the method indicates a tannin content for the sample of about 60 per cent, even though it contains none at all.
With the object of avoiding the palpable errors of the A.L.C.A. method, Wilson and Kern !® set out to devise a method that would determine exactly what is called for in the practical definition of tannin, namely, that portion of the soluble matter of vegetable tanning materials which will precipitate gelatin from solution and which will form compounds with hide fiber which are resistant to washing. The principle of their method is to shake a convenient amount of the tannin solution with a known quantity of purified hide powder until all tannin has been removed from solution, as determined by the gelatin-salt test. The tanned powder is then washed free from soluble matter including the nontannin removed from solution by the hide powder, which is responsible for the large errors in the A.L.C.A. method. It is then carefully dried and analyzed for tannin as in the regular procedure for vegetable-tanned leathers, and from this figure the per cent of tannin in the original material may readily be calculated.
In order to show the workability of this method, Wilson and Kern selected 8 typical tanning materials showing great differences in properties, especially in so-called astringency.. The solid quebracho extract and the four liquid extracts of oak bark, larch bark, chestnut wood, and osage orange are typical samples of the best of these materials on the American market. The gambier is the ordinary pasty product from the East Indies; the sumac, consisting of ground leaves and small twigs, is from Palermo; and the hemlock bark came from the forests of Wisconsin. The extracts were simply dissolved in hot water, cooled slowly, and made up to the mark. The bark and sumac were finely ground and leached by percolation, only the extracted portions being used after making up to a definite volume. In each teser ie grams of hide powder (of known hide substance content) were put into a wide-mouthed, rubber-stoppered, half-pint bottle, the tanning material dissolved in 200 cubic centimeters of solution was added, and the whole was shaken in a rotating box for 6 hours.
The amount of material that could be used was limited by the amount of tannin that the hide powder was capable of taking up in 6 hours. On the other hand it was desirable not to use too little, since the less the amount of tannin fixed per unit of hide substance,. the less the accuracy of the method, since the tannin was determined by difference. Whenever the liquor, after the 6-hour shaking, gave a turbidity or precipitate with the gelatin-salt reagent, the test was repeated with less material.
The tanned powder was washed by shaking with 200 cubic centimeters of water for 30 minutes, squeezing through linen, and repeating the washing operation until the wash water showed no color and gave no test with ferric chloride solution. Except for the osage orange and chestnut wood extracts, which
Sie SU Pee Aan ee ages mre era) ee eee JoIqurer) ec eote ec eee eee eee ee sane JoIquier) C9 Ege Se Pins 8 Oe 8:70) a18-79 (816 ce JOIquier)
are unusual in several respects, not more than 12 washings were required to free the powders from nontannin, which shows that the line of demarcation between tannin and nontannin is fairly sharp for the commoner materials. The wash water continued to extract coloring matter from the powders tanned with osage orange until after the fiftieth washing, while as many as 25 washings were required to free the powders tanned with chestnut wood from soluble matter producing a dark color with ferric chloride. All wash water was tested with the gelatin-salt reagent, but in every case the test was negative.
The washed powders were dried at room temperature for 24 hours or longer and then analyzed for water, ash, fat and hide substance. The per cent of hide substance was taken as the per cent of nitrogen multiplied by 5.62. The difference between 100 and the sum Oietie percentages of water, ash, fat and hide substance was taken as the per cent of tannin in the tanned powder. The parts of tannin per 100 parts of hide substance divided by the parts of tanning material used per part of hide substance gave the per cent of tannin in the original material. The results for the 8 materials examined are given in triplicate in Table XIX.
The two methods just described give very different results. A careful comparison is therefore desirable, especially since it will assist in giving a better understanding of the vegetable tanning process and of what is ordinarily called tannin. It should be remembered that the great majority of tannin values quoted in the literature were obtained either by the A.L.C.A. method or by some method based upon similar principles. The Wilson-Kern method is still too new to have found general acceptance.
Insoluble Soluble Matter Method A.L.C.A
Material Water Matter Nontannin Tannin Tannin Method CHeBIACHO 55... 17.87 ma6 6.96 68.01 47.41 43 Hemlock Bark.... . 8.90 74:33 6.71 10.00 6.17 63 De a Sie rn 52.66 3.68 19.46 24.20 12.88 88 Panenusatk...<s = 51.08 5.88 20.90 22.14 11.71 89 Chestnut Wood.... 58.90 1.50 13.80 25.80 11.90 117 COME Eat wee ss 5's 9.25 47.20 17.990 25.50 9.61 166 Osage Orange..... 46.05 3.45 10.63 39.87 13:37 198 SEES eee eeore 5.30 18.57 24.95 7.79 220
For the sake of comparison, Wilson and Kern analyzed_ the 8 materials they studied by both methods and the results are given in Table XX. The percentage error in the A.L.C.A. method is calculated on the assumption that the results of the Wilson-Kern method are correct. Although the enormous errors in the A,L.C.A. method
Wet Hide Powder
(73 per cent Apparent Percentage water) Used to Per cent of Error Detannize 200 cc. Tannin by Due to Grams Tan Liquor ALL IGaeS Ant Cas Material per Liter Grams Method Method ONERERCHO © eos wee 3 93.3 68.18 44 46.7 67.56 43
are nothing short of sensational, they are probably not at all exaggerated. But the extent of these errors is less surprising in view of the large proportion of such nontannins as gallic acid that appear as tannin by the A.L.C.A. method, as shown in Tables XVII and XVIII.
The need for arbitrary limits in the A.L.C.A. method was clearly shown by the gallic acid experiments, but was more strongly emphasized by similar experiments upon actual tan liquors. The effect of altering the proportion of hide powder with solutions of the 8 tanning materials is shown in Table XXI and in Figs. 88, 89, and 90. In Figs.
88 and 8&9 the short, vertical lines are placed at points on the curves corresponding to the smallest amount of hide powder that would completely detannize the solutions under the conditions of the A.L.C.A. method, as determined by the gelatin-salt test. The crosses indicate the points corresponding to the quantity of hide powder called for in the A.L.C.A. method. The zero points represent the percentages of tannin found by the Wilson-Kern method and the broken portions of the curves are extrapolated.
No scientific reason has ever been given for the selection of the particular amount of hide powder called for in the A.L.C.A. method. So far as the principle of the method is concerned, any of the values given in Table X XI might be accepted as correct, since the solutions were completely detannized in every case. ‘This should be borne in
which have been found by this or similar methods.
As would be expected, the greatest errors in the A.L.C.A. method are obtained with those materials containing the greatest proportion
terials which give the least errors by the A.L.C.A. method are most 20 40 60 80 astringent, while those giving greatseer cee Ape est errors are least astringent. The
a pserabrie a order of the materials in Table XX Fic. 900.—Effect of variation in amount might almost be taken as the order of hide powder used upon the error fdectees . Ith * involved in determining tannin by 2! Gecreasing stringency, althoug the A.L.C.A. method. an exact parallelism cannot be claimed. Quebracho and hemlock
@ ps of nontannin to tannin. Quebracho, z a. having least nontannin, gives the 2 smallest error. However, if the queee, bracho is mixed with gallic acid to x 200 make the proportion of nontannin 5 4160 to tannin about the same as in the ex 160 case of the gambier, it gives errors & 140 nearly as great as in the case of the # 120 gambier, which is shown in Table 100 XXII.
- 80 Comparison of the two methods 3 60 has brought out at least one fact of # 40 practical significance: Those ma©
Powder Percentage Analysis of Mixture of 5 (73 per Parts of Quebracho Extract to 9 Percentage Error in cent water) Parts of Dry Gallic Acid A. L. C. A. Method Used to
200 Cc. A.L. C. A. Method Kern Alone ence of Tan Liquor Insoluble Soluble Matter Method (from Gallic Gambier Grams Water Matter Nontannin Tannin Tannin Fig.90) Acid Alone DSigunecs 5.80 3.96 33-87 56.37 16.93 44 233 273 CaS a a 5.80 3.06 37.14 53.10 16.93 43 214 229 oh Pn aap 5 80 3.06 44.07 46.17 16.93 39 173 190 ete eG ee eae 3.90 53.39 36.85 16.93 33 118 121 Sie es 5.80 3.96 63.34 26.90 16.93 -18 59 72
between astringency and the ratio of nontannin to tannin. Astringency appears to be a function of the rate of combination of tannin and protein, In the experiments listed in Table XIX, the hide powder
fixed more than twice as much tannin from the quebracho liquors in 3 hours as from the gambier liquors in 6 hours. But, when enough gallic acid was added to the stronger quebracho liquors to give them the same ratio of nontannin to tannin as in the gambier, the hide powder did not remove anywhere nearly all the tannin in 6 hours. Upon addition of the gelatin-salt reagent to the liquors after the 6-hour shaking, huge precipitates were formed, suggesting a great reduction in astringency. That the effect was only one of slowing’ up the tanning action was proved by the fact that the hide powder was able to detannize the solution completely in 24 hours. This also explains the mild action of tan liquors which have been used a great many times and have consequently accumulated a large amount of nontannin.
The polemics following the publication of the Wilson-Kern method served to stimulate investigations of the properties of tanning materials. At the 17th annual meeting of the American Leather Chemists Association a formal discussion 7° of the Wilson-Kern method was staged, and the chief aim of the opposition was apparently to show that the low results obtained were due to losses of tannin in the manipulation. It was contended that a certain proportion of the tannin of a liquor will form a stable compound with hide only after long contact, and, further, that even tannin which has already combined with the hide powder will be removed to an appreciable extent during the washing required by the Wilson-Kern method, but no substantial evidence was offered in support of these contentions:
Effect of Washing.
Certain differences in behavior of the several different tanning materials have caused a widespread belief that some tannins form more stable compounds with skin that others; for example, the tannin from gambier is supposed to form a compound with skin less stable than that from hemlock bark. It has also been supposed that mixtures of tanning materials behave differently in this respect from the individual materials.
Wilson and Kern ** made a careful study of the possible losses of tannin during the washing operation involved in their method and came to the conclusion that any such loss was too small to have any effect upon the determination. Table XXIII shows that practically the same results are obtained for a great variety of tanning materials, whether the tanned hide powders were washed 15, 25, or 50 times. Theoretically, tanning may be reversible, but the rate of hydrolysis is so small as to have no bearing on the Wilson-Kern method, which holds equally well for both mild and astringent tanning materials.
20 Printed in full, J. Am. Leather Chem. Assoc. 15 (1920), 451. 71 Nature of the Hide-Tannin Compound and Its Bearing upon Tannin Analysis. J. A. Wilson and E, J. Kern. J. Ind. Eng. Chem, 12 (1920), 1149.
in Powder Per cent Tannin in
Used to Extract. Value Obtained Extract Detannize from Analysis of Gramsin 200 cc. Tanned Powder Washed 2zoocc. Solution 15 25 50 Extract Solution Grams Times Times Times OuebhrachOse a sche e Sens ee ae ee 3.80 10.44 46.84 47.25 46.90 Graber. We ee ee ee oor 10.00 10.44 7.87 7.89 7.67 Gambier-quebracho mixture*.... 6.90 10.44 20.67 20.34 20.43 chestrintewood ste crate bane. 13.60 10.32 tee 13.99 13.93 Hemlock sparke.u.e sees eee 13.00 10.32 23.47 23.38 23.50 Chestnut wood - hemlock bark AUSTUIPO ra ae eee 13.30 10.32 alee 18.73 19.05 Oaksbark ao. t ee ee oe 13.60 10.40 15.52 15.36 15.35 Barchiibar’ fi0cs sien? ost Sete Oe 10.32 —.t 11.29 _ 11.28 ITH AC yen PE ee chen haa ie 13.00 10.39 16.36 16.29 16.39 Wattles bark couicrcta cere eee nie 8.00 10.32 24.66 24.16 24.73
Conversion of Nontannin into Tannin.
In criticizing the Wilson-Kern method, Schultz 2 said, “We have taken the nontannins and washings and reconcentrated them under a high vacuum to the original volume of 200 cc. and have tanned hide powder with it, and, by the calculations employed, we have found a definite percentage of tannin.” He mentioned also that the concentrated liquor gave a positive test for tannin with the gelatin-salt reagent. It might look at first sight as though the detannized liquor and wash waters, before concentrating, really had contained tannin and Schultz evidently so regarded it. Wilson and Kern confirmed Schultz’s experimental finding while analyzing a sample of gambier _ extract by their new method. The detannized liquor and 15 wash waters, all of which gave no test with the gelatin-salt reagent, were concentrated to 200 cubic centimeters, whereupon they were found to give a bulky precipitate with the reagent. But, when diluted back to 3200 cubic centimeters, they still gave a bulky precipitate with the gelatin-salt reagent, showing that a most Important chemical change had taken place during the concentrating.
Another sample of gambier was analyzed by the new method and found to contain 7.94 per cent of tannin. The detannized liquor and 17 wash waters, 3600 cubic centimeters in all, were evaporated to 250 cubic centimeters, analyzed by the new method, and found to contain
GAMBIER EXTRACT.
Two hundred cubic centimeters of solution containing 9.00 grams of extract were detannized with 12 grams of air-dry hide powder, containing 10.40 grams of hide substance, and then the tanned powder was washed 17 times with a total of 3400 cubic centimeters of water. The residual liquor and wash waters were evaporated to 250 cubic centimeters and used to tan 12 grams of fresh hide powder, which was afterwards washed as usual.
a ee ra cer ah Ol Ges 0.14
Pee eloratorm extract)... ..<..c.s<ecseccec cs 0.39 0.42 Boeeevearetance (N x 5.62). ........0isceecece 76.86 79.38 rer SCINETETICE) oo... kas ccc ecco ccs 5.28 3.82 Per 100 grams hide substance: permet TATS 4) Fs. yess cad os ccc e'e 6.87 4.81 Pereeiabe Sed, OTAMS.. 2... cece cece eccs 86.54 86.54 Peter tainitt in extract... ....0..esesese: e704 5.56
of the wash waters, 13.50 per cent.
In order to show that this increased amount of tannin would have combined with the hide powder had it been present in the original solution, Wilson and Kern made up a new solution of this extract, concentrated and diluted back several times, and then analyzed it by the new method, finding 12.69 per cent tannin. If the concentrating had been continued a little longer, the figure 13.50 would probably have been reached or passed. The results are shown in Table XXV.
Dissolved 60.00 grams of extract in 1 liter of water. Concentrated to 250 cubic centimeters and diluted back to 1 liter. Repeated 3 times, the fourth time diluting to 2 liters. Two hundred cubic centimeters of diluted solution, containing 6.00 grams of original extract, were detannized with 12 grams of air-dry hide powder containing 10.37 grams of hide substance, which was afterwards washed as usual.
ale aah gl a Se ee a Un 0.18
Peelerororm extract } iis eescies Shas koe. e. 0.42 eieuvstance (Ni x5.62)......,..02e. dilou. Le. 75.62 Memmnttes by dillerence) <6. cs os os odo ceek cnc ak 5.55 Per 100 grams hide substance:
In spite of the great change in the tan liquor produced by concentrating, it is not shown to any appreciable extent in the analyses by the A.L.C.A. method shown in Table XXVI. Concentrating the tan liquor and diluting back caused a rise in per cent of tannin by the new method from 7.94 to 12.69, but the rise in the A.L.C.A. method is only from 26.14 to 26.40, which difference is so small as even to be attributable to experimental error. The reason for this small difference is probably that the nontannins which are convertible into tannin all combine with the hide powder initially, even though they are easily removed later by washing. ¢
Liquor Liquor
insolublesmatter ss Aco: sear 7.66 8.62 Nonatantitt -. .50.. eee ee 18.33 17.57 SLANT. civic kon he corset eee 26.14 26.40
Just what chemical actions are involved in the conversion of nontannin to tannin must remain a matter for speculation until more ~ data are available; oxidation, condensation, and polymerization may all be involved. It is conceivable that gallic acid might be converted into digallic acid under suitable conditions, and it seems extremely likely that a polymerized form of digallic acid would have tanning properties. A solution of pure gallic acid gives no test for tannin, but Wilson and Kern found that after boiling for some time it gives a bulky precipitate with the gelatin-salt reagent, and will then apparently tan skin. A detannized solution, which gives no test for tannin, can be made to give a strong test merely by passing oxygen gas through it. Long exposure to air has a similar action. It is evident that the Wilson-Kern method furnishes a valuable means of studying the conversion of nontannin into tannin, and might conceivably be applied to a study of the formation of tannin in nature and to the aging of barks. :
The conversion of nontannin into tannin is apparently responsible for two factors of great importance to tanners of heavy leathers, namely, the time factor in tanning and the aging of leather. In the A.L.C.A. discussion referred to, Alsop ?* remarked that sole leather tanned slowly not only contains more tannin, but actually consumes
less tanning material than the rapid tannages. In a private communication to the author, H. R. Procter has called attention to the fact that leather stored for a long time, or aged, before washing contains more tannin than if it had been washed immediately after tanning. A number of critics have said that the Wilson-Kern method is weak because it does not include as tannin all of the material that can be made to combine with hide substance by aging. This argument, however, is weak because the Wilson-Kern method offers a very satisfactory means of studying the aging properties of different tanning materials. An application of the method to such a study is shown in Table XX VII for ten commercial extracts or mixtures thereof.
Errect or AGING UPON PER CENT oF COMBINED TANNIN IN LEATHER.
Three 12-gram portions of hide powder were used to detannize 200 cubic centimeters each of the solutions of tanning materials noted in Table XXIII. One portion in each case was washed 25 times immediately after tanning and the other two were allowed to dry without washing. Of these one was kept exactly 30 days and then washed 25 times; the other was kept just 1 year and then washed 25 times.
Immediately 30 Days 1 Year By
after before before * A.L.C. A. Extract Tanning Washing Washing Method aslo ees sven se es eee 47.25 53.00 54.50 60.87 A 7.80 10.49 14.13 25.61
Oe ES 23.38 24.87 25.46 26.68
Chestnut wood-hemlock bark mixture 18.73 20.45 21.25 25.64 6 0 | Oe, 15.30 17.23 20.08 26.19 rg ek ows as os oeen esos 11.29 13.22 18.73 22.96 MERRIE, Os arose ks coc cee ees 16.29 17.94 17.90 25.51 eSMVAT Po ole dass cise cease ues 24.16 25.80 26.61 33.55
It is interesting to note that in no case does aging for an entire year raise the tannin value to a point as high as that given by the A.L.C.A. method. Aging the gambier-tanned powder for a year raised the tannin content to about the same value as is produced by merely concentrating the liquor before tanning, as indicated in Tables XXIV and XXV. The change taking place upon aging is probably of the same nature as that described above as the conversion of nontannin into tannin.
In the manufacture of vegetable-tanned upper leather, the effect of aging is probably not very marked. In actual practice, Wilson and Kern found barely 50 per cent as much tannin in the leather coming from a certain upper leather yard during a 3-year period as was put into it, according to the analyses by the A.L.C.A. method of the
extracts used. About half of the tannin seemed to be mysteriously disappearing until they applied their new method to the control of the yard and found that the amounts of tannin used and those found in the finished leather then checked easily within the limits of experimental error.
In the manufacture of sole leather, one would expect the effects of aging to be much more pronounced. It seems reasonable to suppose that the Wilson-Kern method could be applied to a sole leather yard by keeping the tanned powders in the dried state for a sufficient length of time before washing to correspond to the conditions under which the sole leather was kept. That the A.L.C.A. method is no more reliable for heavy leather work than for upper leather is indicated by the following figures which have been made available to the author: Of 100 Ibs. of tannin, as determined by the A.L.C.A. method, that enter the leach house, only 39 lbs. appear as combined tannin in the finished leather. Losses in the spent tanning material, waste liquors, and water soluble matter from the leather were determined only by the A.L.C.A. method, but even with all this taken into consideration, there remains a large wilsed=kurn Wsthod loss that can be accounted for only on the assumption that the A.L.C.A. method gives _ results much too high.
study of the effect of adding acetic and hydrochloric acids to extracts of quebracho, mimosa, mangrove,
. of acid affected practically all of the determinations made. Fig. 91, taken from a paper by Wilson and Kern,”> shows how the determination of tannin, by both the A.L.C.A. and the Wilson-Kern methods, is affected by change of pH value. The latter method gives a practically constant value over the wide range 3.6 to 7.3. Where the falling off in per cent of tannin occurs at pH values higher than 7, indicated by the broken line, the results should not be considered as found by this method because in each case the residual solution gave a test for tannin, by the gelatin-salt test, whereas the method specifies that the determination is to be discarded whenever such a test is
Im order to meet the demand for a simpler method, Wilson and Kern 2° modified their method as follows: Standard hide powder is further purified by washing with water to free it from soluble matter, then dehydrating with alcohol, then soaking in two changes of xylene, and then drying. The tan liquor is filtered, as in the A.L.C.A. method, and only the soluble portion used, 100 cubic centimeters being shaken with 2 grams of purified hide powder for 6 hours. The tanned powder is allowed to wash over night in a specially designed percolator and is then dried and weighed. The increase in weight of the dry powder represents the weight of tannin in the roo cubic centimeters of solution used. Wilson and Kern compared the modified and original procedures of their method and found that they give practically identical results for all ordinary extracts. For further details, the original papers should be consulted.
Potential Difference of Tannin Solutions.
In Chapter 5 it was pointed out that the stability of a colloidal dispersion is determined less by the absolute value of the electrical charge on the particles than by the electrical difference of potential between the film of solution wetting the particles and the bulk of the surrounding solution. In the Procter-Wilson theory of tanning, to be discussed in Chapter 13, the astringency of a tan liquor in practice is assumed to be a function of the potential difference between the solution immediately in contact with the tannin particles and the bulk of the tan liquor as well as of the potential difference between the tan liquor and the collagen jelly. Grasser *’ studied the electrochemistry of tannin solutions, but obtained confusing results of rather doubtful value, which may be due to his failure to control or measure the hydrogen-ion concentrations of the liquors.
Thomas and Foster *° were more successful. Using the U-tube electrophoresis method described by Burton,” they succeeded in measuring the potential differences of tannin solutions under different conditions. Table XXVIII shows a series of values obtained for tan liquors made from 8 typical tanning materials. It is interesting | to find gambier, the mildest tanning material, with the lowest potential difference and quebracho, the most astringent, with the highest potential difference. The order of decreasing conductivity of these solutions
was sumac, gambier, oak bark, larch bark, hemlock bark, chestnut wood, osage orange, quebracho. It is evident that the potential difference is not a simple function of the conductivity, but is influenced by the kind as well as the amount of electrolyte present.
Extract Matter per liter volts
Gambler s(Cubeyts ccs. wash ee se oe ee 18.7 — 0.005 OakeDatiasce cere calcaneus ee 17.0 — 0.009 Ciresiniutewood-thrsh ies ono 17.8 — 0.009 Hemlockmoat Kit, o. tek cee 16.7 — 0.010 SUMACT. + ictal buss «lia pee see 19.6 — 0.014 BALCH SHAT Rawat sa he ak ale ae 19.5 — 0.018 (Jsape ornige 7 tet ae ee 13:7 — 0.018 (?) Onebracho7= 2. oo vee ee eee 11.0 — 0.028
If the absolute value of the electrical charge on the particles remains constant, according to the theory given in Chapter 5, the potential difference at the surface should decrease with increasing concentration of electrolyte, or increase with decreasing concentration. Thomas and Foster found that the potential difference of solutions of quebracho extract actually does increase with decreasing concentration, as shown in Table XXIX. The addition of acid decreases the value of the potential difference by lowering the absolute value of the electrical charge, which holds true for negatively charged dispersions in general. This is shown in Table XXX.
Isoelectric Points of the Tannins.
Thomas and Foster 2° later extended their investigations in an attempt to determine the isoelectric points of tannins from different sources. The various tanning extracts were dissolved in a citrate buffer mixture having a pH value of 2.0 and the solutions were finally adjusted to the desired pH values by means of the hydrogen electrode. The buffer was apparently necessary to eliminate, or delay, the secondary actions, such as diffusion of the boundaries and change of reaction of the extracts due to electrolysis, which behavior had nullified previous experiments.
Between the pH values 2.5 and 2.0, the direction of migration of the tannin particles changed from anodic to cathodic in solutions of the extracts of oak bark, hemlock bark, wattle bark, sumac, and gambier. In the case of quebracho, there seemed to be no movement in the U-tube at the pH values 3.0 or 2.5, but at 2.0 the movement seemed to be slightly cathodic. Quebracho was precipitated by the buffer and only the clear, supernatant liquor could be used, which may account for the inability to obtain more definite results.
Until they are located more definitely, the isoelectric points of the tannins may be accepted as lying between the pH values 2.0 and 2.5, at least those of hemlock, oak, and wattle barks, sumac, and gambier.
Precipitation of Tan Liquors.
In the hope of throwing some light upon the colloidal nature of the tannins, Thomas and Foster studied the action of various electrolytes upon a great variety of tan liquors. Aqueous solutions of different tanning extracts were made up so that 100 cubic centimeters of solution contained 4 grams of solid matter. The solutions were made at 85° C., cooled to 25°, and then adjusted to final volume. The stock solution was then centrifuged for 5 minutes at 1000 times gravity in
order to throw down coarse suspended matter. Portions of 25 cubic centimeters were put into 100-cubic centimeter, graduated oil tubes. Then 25 cubic centimeters of the electrolyte were added, the solutions were allowed to stand for 15 to 30 minutes for precipitation to start, and were then centrifuged for 5 minutes at 1000 times gravity, The volumes of the precipitates were recorded and plotted against the concentrations of electrolyte employed.
The results may be most conveniently studied by grouping them wader the names of the various electrolytes used. Each available extract was not tested with all electrolytes because, in some cases, preliminary experiments indicated that further work would be fruitless.
Monovalent Cations.
Potassium chloride. Concentrations of potassium chloride from 0.02 to 4 molar gave only negligible amounts of precipitate with gambier and quebracho. Oak bark gave a gradually increasing salting out effect.
MM MM M M M 234 6M MM MM MM M oM
10050 2510 4 2 7 10050 2010 495% Concentration of Acid Concentration of Sulfuric Acid Fic. 92.—Precipitation of Tannins by Hie 03.—Precipitation of Tannins by Hydrochloric and Phosphoric Acids. Sulfuric Acid. ©
Since gambier and quebracho represent extreme types of tanning extracts, no further tests were made with this salt. It must be borne in mind that the solutions to which the neutral salts were added were made simply by dissolving the extracts in distilled water and had pH values in the vicinity of 4.5.
Hydrochloric acid. Concentrations from 0.01 to 6 molar were used. Gambier and quebracho gave large amounts of precipitate only at high concentrations of acid and, since this was not a simple colloid precipitation, no further experiments were attempted. A salting out effect was obtained with oak bark. (See Fig. 92.)
Sulfuric acid. Quebracho, hemlock bark, oak bark, and larch bark gave progressively increasing amounts of precipitate with increasing concentration of acid, as shown in Fig. 93. No precipitate was obtained with sumac until molar concentration was reached, when gummy
sulfate. At 4 molar concentration, a flocculent precipitate was formed.
Phosphoric acid. Gambier began to give an appreciable precipitate only at 4 to 7 molar concentration. With sumac a gummy mass was thrown out at 2 molar, as was observed upon the addition of sulfuric acid and aluminum sulfate, and at 4 to 7 molar a flocculent precipitate formed which left the supernatant solution almost colorless. Quebracho was progressively salted out. (See Fig. 92.)
Acetic acid. Experiments with quebracho, sumac, gambier, and oak bark were run with concentrations of acid from 0.005 to 4 molar. There was no appreciable precipitation in any case. At the higher concentrations the suspended matter began to dissolve.
Concentration of Acid Concentration of Barium Chloride Fic. 94.—Precipitation of Tannins by Fic. 95.—Precipitation of Tannins Formic and Lactic Acids. by Barium Chloride.
gave no precipitation up to 4 molar, at which concentration the suspended matter began to dissolve. Quebracho and quercitron bark were precipitated, but the precipitate redissolved at from 2 to 4 molar.
. Lactic acid. Concentrations from 0.005 to 2 molar were employed. The effects of this acid were similar in kind, but not in degree, to those with formic acid. (See Fig. 94.) The precipitates with quebracho and quercitron redissolved at lower concentrations of lactic than of formic acid. Since lactic is the weaker acid and since this redissolving was not found with hydrochloric or sulfuric acids, the effect must be due to chemical properties other than those of the hydrogen ion. This is an important point to consider in the chemical control of tan liquors.
Calcium chloride. Concentrations up to 2 molar were used. As with barium chloride, increasing amounts of precipitate were obtained with the different tanning materials used, as shown in Fig. 96. At the same concentration of these salts the different extracts gave in some
MMMM MM M M 2 3M
20010050 2010 4 B T 800 40020010060 2010 4 Concentration of Calcium Chloride Concentration of Aluminum Sulfate Fic. 96.—Precipitation of Tannins F'1c. 97.—Precipitation of Tannins by
cipitation of negatively charged colloidal dispersions, aluminum sulfate is not only a powerful precipitant, but it also gives the “irregular series” or “tolerance zone” which is typical of the action of weak base cation-strong acid anion salts, as shown by Buxton and
was obtained with gambier, sumac, oak bark, and quercitron bark. Precipitation generally set in at 0.00125 molar concentration, rose rapidly to a maximum, dropped off into a “tolerance zone,” and then started upward again, as shown in Fig. 97.
Those which gave no “irregular series,” at least up to 0.5 molar concentration of the salt, were osage orange, quebracho, camel cutch, chestnut wood, chestnut oak bark, hemlock bark, and larch bark, shown
in Fig. 98. Precipitation started at 0.00125 molar and increased gradually to about 0.1 molar, where there was an abrupt upward trend similar to a salting out effect. These extracts are not so sensitive to precipitation by dilute solutions of aluminum sulfate as those shown
The effect of hydrogen-ion concentration upon the precipitation of solutions of quebracho, gambier, larch bark, and oak bark by sulfuric, hydrochloric, and formic acids is shown in Figs. 99, 100, IoI, and to2. Solutions of sumac, hemlock bark, and wattle bark were not precipitated by these acids with increasing acidity to pH =1. It is evident that the volume of precipitate formed is not a function of
different shapes.
Wherever a precipitate formed, the amount invariably increased with increasing hydrogen-ion concentration where hydrochloric and sulfuric acids were used. But an increasing concentration of formic acid dissolved the precipitate, or the suspended matter in cases where no precipitate had previously formed.
The precipitates obtained with hydrochloric acid were found to be soluble in strong alcohol and in 9 molar lactic acid. On shaking up with water, these precipitates dispersed, but gradually settled out more or less completely in 24 hours. In the case of oak bark and quebracho, it was found that approximately two-thirds of the original solid matter present had been precipitated at pH = 1.
When the pH value was increased by the addition of sodium hydroxide, there was increasing solution, clear liquids being obtained in every case at pH = 8. The effect of adding calcium hydroxide, however, is very different, as will be recalled from Fig. 87 of Chapter 11.
The conduct of the extracts examined by Thomas and Foster shows that they contain.a large amount of colloidal matter of a type of dispersion with properties between those of the intermediate and hydrophilic dispersions. From the colloidal point of view, vegetable tanning materials furnish an almost unexplored field; the work outlined in this chapter cannot be considered as more than a good start.
Raw skin is readily putrescible in the wet state. Upon drying, the collagen fibers become glued together and the skin becomes very stiff. Although the dried skin will not putrefy, it again becomes putrescible as soon as it comes into contact with water. Thousands of years ago the discovery was made that the properties of skin substance change completely when the wet skin is brought into contact with the aqueous extract of those forms of plant life which have since come to be classed as vegetable tanning materials. The action which brings about this change of properties is known as vegetable tanning and the compound of skin protein and tannin as leather. Under normal conditions, the fibers of leather do not glue together upon drying and they are not putrescible even in the wet state.
The practice of tanning is greatly complicated by the necessity for endowing the leather with many delicate properties, according to the use to which it is to be put, all of which are markedly affected by slight differences in manipulation. The effect produced by any single change in the tanning process depends upon the nature of every one of the numerous operations preceding and following that in which the change has been made. In the manufacture of one type of leather, a skin may be subjected to scores of different operations and a slight change in any one of these may necessitate changes in nearly all of the others in order to preserve the specific properties desired in the finished leather. It is this fact that renders most practical treatises of leather manufacture of so little value to the tanner. Were he to try to adopt an operation described in the literature which was better in itself than the one he was using, he might find that the change would spoil his leather because of its failure to harmonize with all of the other operations peculiar to his particular process. There are, however, certain broad principles of tanning which are followed generally.
‘Two conditions may be accepted as essential to successful tanning: the first that the natural physical structure of the skin shall be changed but very little; the second that the degree of tannage shall be as nearly uniform as possible throughout the skin. The second condition, in a large measure, is essential to the first.
The physical means widely adopted to preserve the natural struc-_ ture of the skins during tanning is to suspend them freely from sticks with the heads hanging downward in the tan liquors, care being taken to see that the unhaired skin is free from creases or wrinkles, which
would be permanently fixed by the tannage. Usually the lower end of each skin is tacked onto a stick and the skin is then spread out carefully so that it hangs in its natural condition when immersed in the tan liquor. The supporting stick rests upon a rectangular frame floating in the liquor. The skins are not subjected to any violent mechanical agitation until the grain surface has been “set” by the tannage and the tannins have penetrated into the skin for a considerable distance.
If skins from the beamhouse were put directly into strong tan liquors of such reaction that the rate of combination of tannin with the skin protein was abnormally great compared to the rate of dif- fusion of tannin into the interior of the skin, the tendency for the outer layers to assume an area different from that of the skin as a whole would cause a distortion of the skin that would be permanent. In such a case, the liquor is called very astringent. The fact is often overlooked that the reaction of the solution previously absorbed by the skin may be as important in bringing about this condition as the reaction of the tan liquor itself. In fact a given tan liquor may appear very astringent to a pickled skin and yet very mild to a skin taken directly from the bate liquor. The distortion may show itself as coarse wrinkles, as the finer reticulation illustrated in Fig. 48 of Chapter 5, or merely as a rough grain surface. Since these distortions greatly lower the value of the leather, every effort is made to avoid them.
The practical means adopted by the tanners to eliminate this danger is to hang the skins from the beamhouse first in a tan liquor which has been used to tan a great many lots of skins previously and in which the ratio of nontannin to tannin is very great. Each day the skins are then moved into stronger and fresher liquors until completely tanned. The effect of an increasing ratio of nontannin to tannin in the tan liquor is to increase the ratio of the rate of diffusion of the tannin into the skin to the rate of combination of the tannin with the skin protein. This has the obvious effect of making the rate of combination more uniform throughout the skin, and consequently lessening the tendency towards distortion. The ideal process would be the one in which combination was entirely prevented until the tannin was uniformly distributed throughout the skin and then allowed to proceed uniformly by a suitable change of reaction of the liquor. Another safeguard which tanners have been forced to adopt, without understanding its mechanism, is so to regulate the reactions of both the tan liquors and the solution absorbed by the skin proteins just prior to tanning that the tanned and untanned portions of the skin protein do not tend to assume greatly different specific volumes.
The progress of the diffusion of the tan liquor into the skin is determined by cutting off a strip and observing the color of the freshly exposed portfon. The raw portion is white and the tanned layers usually a deep brown. When the tannin has penetrated almost to the middle of the skin, it is customary to take the skins off from the sticks and pile them into vats known as handlers or layers. The name handler is used when the skins are handled from vat to vat at fre-
quent intervals until completely tanned. The name layer is used for the vats in which heavy hides are laid away for long periods, during which the tannin diffuses very slowly into the interior. Although hardly more than a week is consumed in the diffusion of the tan liquor into a light skin, months are required in some processes of sole leather manufacture. :
Where great solidity is required, as in sole leather, it is not sufficient merely to convert all of the collagen into leather. The volume of the collagen fibers increases as more tannin combines with them. After the hides have become completely colored throughout, it is customary to treat them with very strong tan liquors with the object of getting as much tannin fixed as possible, and mechanical agitation of one kind or another is often employed. Usually the weight of sole leather is further increased by the incorporation of glucose and magnesium sulfate in the leather.
The Structures of Tanned Skins.
In the manufacture of leather for definite purposes, the choice of the kind of skin is of the greatest importance. By varying the nature of the tanning process, the properties of the leather can be varied, but not sufficiently to make one kind of skin suit all purposes. Advantage is taken of the variety of skins furnished by nature in order to simplify the tanning process itself.
Fig. 103 shows a vertical section taken from the butt of a steer hide tanned for sole leather. The natural solidity of this hide 1s so great that a heavy degree of tannage would not have been necessary in order to produce a leather suitable for shoe soles. This particular leather was heavily tanned with oak bark extract, but was not loaded — with glucose and magnesium sulfate.
A section of vegetable tanned calf skin is shown in Fig. 143 of Chapter 14, where it was put for direct comparison with chrome tanned calf made from part of the same skin. It is interesting to compare its structure after tanning with that of calf skin in the fresh state, shown in Fig. 18 of Chapter 2. The leather is typical of the finest grade of finished shoe upper leather.
Fig. 104 shows a section of vegetable tanned sheep skin just as it came from the tan liquors. Note the great contrast which it presents to the leather made from steer hide or calf skin. The holes and empty spaces left by the wool and glands give the leather a sponginess that makes it unsuitable for many purposes. The upper layer is often split from the rest of the skin and used in bookbinding, for hat bands and for the linings of expensive shoes instead of cloth. Sheep skin leather is sometimes used as a substitute for kid leather in the manufacture of gloves, where its softness is an asstt. The raw skin is shown in Fig. 28. |
Fig. 105 is a section of vegetable tanned leather from the butt, or shell, of a horse hide. This is finished leather ready for use in the manufacture of the uppers of heavy, waterproof shoes. The raw
hide, at much lower magnification, is shown in Fig. 31. It will be noted that the leather has been split into layers through the portion known as the glassy layer, only the upper layer being used. The compactness of the fibers in the bottom third of the leather makes it waterproof and almost airtight. Leather from this part of the horse hide is known as Cordovan. The section should be compared with Fig. 145 of Chapter 14, which shows a section from the same butt which has been chrome tanned; the contrast is. striking.
The peculiarity of the horse hide is that this compact fibrous structure is found only in the butt, the rest of the hide being very loose in texture. Fig. 106 shows a section taken from the same piece of leather as that shown in Fig. 105, but from a point further up the back beyond the boundary of the glassy layer. Its softness and
The section shown in Fig. 107 is that of a vegetable tanned hog skin.
A section of the fresh skin is shown in Fig. 30. When the flesh side of the leather was shaved to make it smooth, the bottom of the pocket of the hair follicle was cut away, leaving the hole running right through the leather, as shown in the figure. This is typical of hog leathers; wherever there were bristles in the original skin, holes pierce the final leather. The roughness of the grain surface of the leather gives it a place in the manufacture of saddles, football covers, purses, etc. | )
Fig. 108 shows a vertical section of salmon leather taken directly from the vegetable tan liquors. It should be compared with the section of fresh skin shown in Fig. 36. The gap in the upper portion is the follicle once occupied by a scale. The structure of the leather makes it suitable for belt lacings.
The raspy feel of certain kinds of shark leather is explained by the section shown in Fig. 109. Shark leather has recently been tried for shoe uppers, in which case the hooks are removed prior to tanning. The fibrous structure resembles that of other fishes.
Fig. 110 shows a vertical section of vegetable tanned alligator skin. This type of leather finds an outlet in the manufacture of bags and cases. Fig. 111 shows a section of leather made from the skin of a horned toad.. Although these skins are very small, they make very pretty doilies and fancy purses. In both the alligator and toad skins, the fibrous structure resembles that of the fishes.
A section of leather made from camel skin is shown in Fig. 112. It is remarkable for its compact structure, which would make it suitable for belting leather or for light soles. Figs. 113 and 114 show portions of the section of a vegetable tanned walrus hide and Figs. Ir5 and 116 show sections of the tanned hide of a hippopotamus.* The most remarkable thing about these hides is their great size. The actual thickness of the walrus leather was 24 millimeters and that of the hippopotamus leather 30 millimeters. In order to show the entire
Thickness of section: 20 u. Objective: 16-mm. Stain: Daub’s bismarck brown. Wratten filter: H-blue green. Tannage: vegetable. Magnification: 70 diameters.
Tannage: vegetable. Magnification: 30 diameters.
Portions of Vertical Section of Walrus Leather. Fic. 113.—Region of Grain Surface. fic, 114.—Region 22 Millimeters Below Grain Surface.
Portions of Vertical Section of Hippopotamus Leather. Fic. 115.—Region of Grain Surface. Fic. 116.—Region 28 Millimeters Below Grain Surface.
high would be required.
The walrus must be very sensitive to touch, if we may judge from the highly developed papillae which protrude everywhere from the grain surface. In neither of these leathers were the roots of the hair removed and the fat cells surrounding the hair bulbs of the walrus were still-intact as though the unhairing liquors had not penetrated that deeply. Except for the huge collagen fibers in the reticular layer, and the great size of the hide, the walrus hide resembles that of the common hog. It is interesting to compare the fibers of these leathers with those of the smaller skins, but the differences in magnification must be taken into consideration.
It has often been supposed that the tanning action consists of a coating of the skin fibers with tannin, but observations of sections under the microscope indicate that this is not the case. The outer surfaces of the skin act as filters, permitting only the soluble matter to pass into the interior, where it subsequently diffuses into the substance of the fibers, which assume a uniform color throughout when tanning is finally complete. In finished leather, contrary to what seems to be the general belief, we find no coating of the surfaces of the fibers nor any material precipitated in the spaces between them.
Rate of Diffusion of Tan Liquor into Gelatin Jelly.
The great length of time required to tan heavy leathers is due to the very slow rate of. diffusion of the tannin into the interior of the hides. Because of the difficulty of measuring the extent of penetration of tan liquors into raw hides, studies of the rate of diffusion are usually made with tubes of gelatin jelly. Hoppenstedt ? noted that different tanning extracts diffused into gelatin jelly at different rates, the order of increasing rate of diffusion being mangrove bark, quebracho, hemlock bark, algarobilla, valonia, oak bark, myrobalans, chestnut wood, gambier, divi-divi, sumac.
Later Thomas ** showed that the rate of diffusion of tanning extracts into gelatin jelly increases with the ratio of nontannin to tannin in the extract. For typical samples, he found the rate of diffusion increasing in the order quebracho, hemlock bark, larch bark, oak bark, chestnut wood, gambier, sumac, agreeing with the results obtained by Hoppenstedt. This is also the order for decreasing astringency of these materials, as ordinarily used. The same order is roughly borne out in experiments dealing with the rate of diffusion into cow hide.
The action of nontannins in increasing the rate of diffusion of tannins into skin may be explained as follows: Tannins and certain nontannins form compounds with collagen, but the collagen-tannin compound is very stable, while the collagen-nontannin compounds are
MEGEITABLE TANNING 257
considerably dissociated. The nontannins, having a much smaller molecular weight than the tannins, diffuse more rapidly into the skin. When the slowly moving tannin reaches a point where it would combine with collagen, it cannot do so because the point is already occupied by nontannin. Tannin that would otherwise have combined with collagen near the surface of the skin is thus enabled to proceed into the interior and the measured rate of penetration is thereby increased. ‘This action is more marked the greater the concentration of nontannin capable of combining with collagen. The collagen-tannin compound being much the more stable, tannin replaces nontannin as fast as the collagen-nontannin compound hydrolyzes.
According to the Procter-Wilson theory of tanning, to be discussed presently, the rate of tanning, and also of the combination of collagen with certain nontannins, can be decreased either by increasing the electrolyte concentration or by lowering the positive electrical charge which collagen possesses in acid solution, which can be accomplished by decreasing the acidity. We should therefore expect the constituents of a tan liquor, both tannin and nontannin, to penetrate skin more rapidly as the acidity of the tan liquor is decreased to the isoelectric point of collagen.
Thomas prepared a 5-per cent dispersion of gelatin in hot water containing 0.1 per cent ferric chloride and poured it into a series of test tubes to three-quarters of their capacity. When the dispersions had set to jelly, equal volumes of solutions of different extracts were poured on top of the jellies, which were then placed in an ice box. All of the extract solutions were made to contain 1 per cent of dry solid matter. Tannin and some nontannins react with ferric chloric giving very deep green or blue colors, which served to indicate the extent of the penetration. In 96 hours the gambier had penetrated 18.0 millimeters as against only 4.8 millimeters by the quebracho. It was, of course, the extent of penetration by certain nontannins that was measured, as these diffuse more rapidly than the tannin.
Wilson and Kern * treated a large volume of a dispersion of gelatin in dilute ferric chloride solution with tartaric acid until its pH value was reduced to 2.5, as determined by the hydrogen electrode. Equal portions were then treated with sodium hydroxide to give the desired pH values, which ranged from 2.5 to 11.0. Dilutions were such that the final dispersions contained 5 per cent of gelatin and 0.1 per cent of ferric chloride, as in the experiments of Thomas.
Solutions of gambier and quebracho extracts were treated with tartaric acid to give a pH value of 2.5. Equal portions were then treated with sodium hydroxide to give series of pH values the same as in the series of jellies. Each final liquor contained 1 gram of solid matter of the original extract per 100 cubic centimeters. aeaye
The gelatin dispersions were poured into test tubes and allowed to set. Onto each was poured a given volume of tan liquor having the same pH value as the jelly. Both the quebracho and gambier series
were run in duplicate. They were kept in the ice box and examined at intervals for 96 hours. The extent of the diffusion of the tan liquors into the jellies is shown in Fig. 117, the measurements being taken after 96 hours. In each case the duplicate series were practically identical.
Gambier, which has a high
ratio of nontannin to tannin, begins to penetrate at a pH value of 3.0 and reaches its maximum rate at pH = 6.0. Quebracho, on the
Tan Liquor.
An extremely important series of investigations of the nature of the vegetable tanning process has recently been begun by Thomas and Kelly, which promises to throw much light on the mechanism of this very complex process. Their first studies*® were devoted to the effects of time and concentration. In their preliminary experiments, portions of purified hide powder were shaken with definite quantities of unfiltered solutions of tanning extracts for stated lengths of time, washed free from soluble matter, and then analyzed for the purpose of determining the amount of tannin combined with a unit of hide substance. © In the more concentrated liquors, however, an error was introduced by the occlusion of insoluble matter by the hide powder, which was included as combined tannin because it was not removed later by washing.
In their most recent work, Thomas and Kelly adopted a method practically identical with the modified Wilson-Kern method of tannin analysis described in Chapter 12, except for the fact that no attempt was made to detannize the various solutions completely. All tan liquors were centrifuged and filtered and only the clear filtrates used in the experiments. The use of filtered liquors with hide powder gave results which were more uniform and which probably represent actual tanning conditions more. closely, since the surfaces of the whole skin act as filters, permitting only the soluble matter to come into contact with the great bulk of the skin protein.
Tan Liquor. Time, 24 hours. Tan Liquor. Time, 24 hours.
Portions of purified hide powder equal to 2 grams of anhydrous substance were shaken with I00 cubic centimeters of tan liquor of the desired concentration and for fixed intervals of time. The powder was then washed until the. wash water no longer gave a dark color upon the addition of a drop of ferric chloride solution. It was found that the ferric chloride test is capable of detecting I part in 75,000 of either gallic acid or pyrogallol. The powders, freed from soluble matter, were dried in a current of warm air and then completely dried in the oven. The increase in weight of the absolutely dry material was taken as the amount of tannin fixed by 2 grams of hide powder.
bark, gambier, oak bark, and wattle bark extracts. The mild action of gambier, as contrasted with the astringency of quebracho, is graphically shown by the steep rise of the quebracho curve compared
with that of the gambier series. It is remarkable that all extracts give curves of similar shape and having points of maximum at the relatively low concentrations ordinarily used in practice. Thomas and
Kelly showed definitely that the rise and fall in the curves cannot be attributed to variations in hydrogen-ion concentration, but is due to the increasing concentration of the other constitutents of the tan liquors.
One explanation given for the appearance of points of maximum in the curves is that the rate of combination of tannin and hide substance increases so rapidly, with increasing concentration of tan liquor,
that it soon reaches a point where the surfaces of the hide fibers quickly become so heavily tanned that they are rendered less permeable to the tannin remaining in solution. The interior of the fibers are thus prevented from tanning so rapidly, which accounts for the smaller amount of tannin fixed by the hide powder in the stronger solutions. Another explanation is furnished by the work of Thomas and Foster,° who observed that the electrical difference of potential at the surface of tannin particles decreases with increasing concentration of tan liquor. This would lessen the attraction between the tannin particles and the protein jelly and thus cause a decrease in the rate of combination. This seems the more probable explanation because a greater rate of diffusion of tan liquor into skin is obtained in practice by using more concentrated solutions. The curves represent the resultant of two effects: the increasing concentration of tannin tends to cause an increase in the rate of tanning and the increasing concentration of nontannin tends to cause a decrease in the rate of tanning. The point of maximum represents the point at which the effect of the increasing concentration of nontannin becomes greater than that of the tannin.
These curves are in agreement with the findings of a number of investigators that highly concentrated tan liquors are very much less astringent than those of moderate concentrations. In practice, the degrees of astringency of tan liquors seem to follow curves similar to those in the figures. The use of concentrated liquors in tanning has been suggested by Seymour-Jones* and by Enna,® but the idea seems not to have been widely adopted, probably because it introduces complications in the later processes not easily overcome without some loss in quality of the finished leather.
Thomas and Kelly® next turned their attention to the effect of the pH value of tan liquors upon the fixation of tannin by hide substance. The procedure adopted was the same as in the studies of the effect of concentration. In each case the pH value of the tan liquor, as determined by the hydrogen electrode, was adjusted to the desired value by the addition of sodium hydroxide or hydrochloric acid, Figs. 120 and 121 show the effect of change of pH value on the rate of the tanning of hide powder by solutions of quebracho, gambier, oak bark, wattle bark, hemlock bark, and larch bark ex. tracts. The curves contain a mine of information that requires careful study.
The most elaborate set of curves is that for hemlock bark exiract, 8 Ind. Eng Chose eed eae Tanning Extracts. A. W. Thomas and S. B. Foster, . erates. Tanning of Sole Leather. Alfred Seymour-Jones. J. Soc. Leather Trades Chem.
which may be discussed as typical. In the concentration experiments, a tan liquor containing 24 grams of solid matter per liter gave a much greater rate of tanning than one containing 80 grams per liter, but the curves in Fig. 121 show that this is dependent upon the pH value; at pH = 5, the more dilute solution tans at the greater rate, while at 2 and at 8, the more concentrated solution tans at the greater rate.
In tanning for 24 hours, there is a steep rise in all curves to the left of pH = 5, which is exactly what one would expect, knowing that the positive electrical charge on collagen increases as the pH value falls from the isoelectric point and that the tannins are negatively charged at pH values higher than 2. In some cases a falling off in rate of tanning as the pH value drops below 2 is noticeable, but it must be remembered that the great tendency for collagen to swell and to hydrolyze at high acidities makes it difficult to get reliable data at pH values as low as 2.
The most curious parts of the curves are those bétween the pH values 5 and 8. Since tannin particles are negatively charged in this region, the question that naturally arises is the possibility that the collagen may become increasingly positive with rise of pH value from 5 to about 8. This might seem an absurd view were it not for the two points of minimum plumping of calf skin found by Wilson and Gallun and shown in Fig. 73 of Chapter 9. Here it was suggested that collagen undergoes a change of form, possibly an internal rearrangement, in passing from an acid to an alkaline solution and that the two points of minimum, at pH = 5.0 andsat pli t="7.7, 1epresent the isoelectric points of the two forms. We may refer to collagen stable in acid solution as form A and collagen stable in alkaline solution as form B. As the pH value is increased from 5.0 to 7.7, if the conversion of form A into form B proceeds at a greater rate than the formation of negatively charged ions of form A, then we should expect the net charge on the collagen structure to become increasingly positive, which would result in an increased rate of tanning.
The question was raised in discussion as to whether any fixation of tannin actually took place at pH values below 2 and above S2ein all of the experiments described, the powders were washed with disstilled water immediately after being taken from the tan liquor. Distilled water usually has a pH value of about 5.8, due to dissolved carbonic acid, and this would tend to make the pH value of the solution absorbed by the collagen jelly approach the value 5.8 before it was all washed out and the observed fixation of tanning might have occurred during the washing rather than during the shaking with tan liquor. Thomas and Kelly showed, however, that fixation actually does take place at pH values below 2 and above 8.
They prepared a solution of wattle bark extract containing 40 grams of solid matter per liter and hydrochloric acid to bring the pH value to 0.87. Four portions of hide powder were tanned with this solution for 24 hours in the prescribed manner and then two were
washed with distilled water and two with a hydrochloric acid solution having a pH value of 0.87 until no more tannin could be extracted. The latter two were then washed free from hydrochloric acid with distilled water. The two powders washed with the acid solution were found to contain an average of 0.739 gram tannin combined with the original 2 grams of hide powder against 0.987 gram tannin for the powders washed with distilled water. This shows that, although washing with distilled water causes an increase in combined tannin found, there is actually a fixation of tanning taking place at pHi'0.87;
the Same pH Value as the Tan Liquor Used in Tanning.
They then prepared two series of solutions of hemlock bark extract, containing 24 grams of solid matter per liter and having pH values ranging from 1 to 10, as determined by the hydrogen electrode. Portions of hide powder were tanned in each series for 24 hours in the prescribed manner and then the powders of one series were washed with distilled water, while those of the other were washed free from soluble tannin with solutions having the same pH values as the liquors in which the powders were tanned. For pH values of 4 or less, the solutions used for washing contained only hydrochloric acid; for pH values from 5 to 9, they were made from M/rs sodium phosphate adjusted to the desired pH value with HCl or N aOH ; for pH = 10, a solution of sodium hydroxide was used. The final washing was done with distilled water. The results are shown in
Fig. 122. The two curves are not identical, but show plainly that tannin combines with hide substance at all pH values from I to Io. Where a buffer solution was used to wash the hide powder tanned at pH = 5, a greater fixation of tannin occurred. Salts at low concentration have the property of increasing the fixation of tannin at pH = 5, as will be shown later.
While studying the action of solutions of acid and alkali upon leather previously freed from water soluble matter, Wilson and Kern* found that tannin was extracted by dilute solutions of alkali, but not of acid. In an attempt to locate the pH value at which the collagentannin compound begins to hydrolyze, they performed the following experiment. A large amount of purified hide powder was tanned with quebracho extract at a pH value of 4.6, washed free from all soluble matter with distilled water, and then dried. Seven large reservoirs of buffer solutions were prepared by making up solutions of tenthmolar phosphoric acid with sodium hydroxide to produce the pH values 5, 6, 7, 8, 9, 10, and 11, respectively. Eight-gram portions of the tanned powder were put into Wilson-Kern extractors ™ and extracted with 4 liters of buffer solution, taking just 6 hours for all of the solution to percolate through the tanned powder. Each portion was extracted with a solution of different pH value. The extracted powders were washed free from buffer solution with distilled water and were then dried and analyzed for comparison with the original powder. All extracts were brought to a pH value of 4 and then tested for tannin with the gelatin-salt reagent. The buffer solutions extracted only negligible amounts of nitrogen from the powders. The results are shown in Table XXXII.
mR ey aa se nw ees fe 0.2 0.4 0.5 0.4 0.6 0.3 0.5 0.4 Hide substance (N x 5.62).. 84.2 83.9 83.9 83.9 84.2 847 84.9 85.3 Tannin (by difference)..... 15.6 15.7 15.6 15.7 15.2 15.0 14,60) Gi43 Per cent of total tannin ex-
Test for tannin in extract...... neg. neg. meg. pos. pos. pos. pos.
Leather tanned at pH = 4.6 is apparently resistant to hydrolysis by solutions having pH values up to some point between 7 and 8, but is at least partially hydrolyzed, and with increasing speed, as the
pH value is increased above 8. This adds some weight to the suggestion that 7.7 represents the isoelectric point of one form of collagen. But, taken in conjunction with the finding of Thomas and Kelly that collagen and tannin form stable compounds at pH values greater than 8, it also supports their view that the collagen-tannin compound formed in alkaline solution is different from that formed in acid solution, which will be made clearer when their later experiments are described.
Adding Sodium Chloride Adding Sodium Sulfate
Fic, 123.—Effect of Sodium Chloride Fic. 124—Effect of Sodium Sulfate and pH Value upon the Rate of and pH Value upon the Rate of Tanning. Time, 24 hours. Tanning. Time, 24 hours.
lock extracts, at different pH values, has recently been studied by Thomas and Kelly.'’* In each test, 100 cubic centimeters of tan liquor, a weighed amount of salt, and the equivalent of 2 grams of water-free hide powder were put into a bottle and shaken, in a rotating box, for 24 hours. The contents were then transferred to a Wilson-Kern extractor, filtered, and washed until the washings gave no coloration with ferric chloride solution. The tanned powders were then dried in a vacuum at 100° C. and weighed, the increase in weight of the dry powder being taken as tannin fixed.
In order to guard against including as fixed tannin any matters rendered insoluble by the added salt, blanks were run leaving out the hide powder and corrections were made where necessary.
The insoluble matter of the extracts was first removed by centrifuging strong solutions, which were then diluted to contain 40 grams of solid matter of the tanning extract per liter, after adjusting the pH value to 2, 5, or 8, by addition of hydrochloric acid or sodium hydroxide.
The effect of sodium chloride is shown in Fig. 123 and that of sodium sulfate in Fig. 124. At pH =2, both salts retard tanning to a very considerable extent, although sodium sulfate is always much more effective in this respect than sodium chloride. In each case the extent of the retardation is greater the higher the concentration of salt. At pH =8, the action of the salts is similar, but less pronounced. At pH = 5, the action is still less pronounced and is even reversed by concentrations of sodium chloride less than twice molar, which seem to cause an increase in rate of fixation of tannin.
The marked reduction in the rate of tanning at pH = 2 exerted by the salts is probably due primarily to the reduction of the electrical differences of potential between the collagen jelly and the liquor on the one hand and between the liquor and the surface film surrounding the tannin particles on the other. The potential difference between collagen jelly and liquor is probably at its maximum value in the vicinity of pH = 2 and, consequently, the depressing action of salt should be greatest at this point. According to the Procter-Wilson theory of tanning, a diminution in this potential difference must result in a decrease in rate of tanning. The greater effect of sodium sulfate may be attributed to the divalent sulfate ion, as explained in Chapter 5.
With the decreasing potential difference between the liquor and the surface film of solution in contact with the tannin particles, there would be an increasing tendency for the tannin particles to form aggregates and finally to precipitate out, further decreasing the rate of combination of tannin with collagen.
The effect of hydration of the added salt is to remove water from the role of solvent, as explained in Chapter 4, and this would cause a virtual increase in concentration of tannin. Thomas and Kelly point out that opposed to this, within certain limits, would be the tendency for the salt to cause an aggregation of the particles of tannin. These opposing actions may explain the behavior of sodium chloride at pH=s5. At this point the potential difference between the collagen jelly and the liquor would be near its minimum value and hence would be but little affected by the salt. The effects of hydration and of aggregation would therefore be much more pronounced at this point, and Thomas and Kelly suggest that the increase in rate of tanning by molar and half-molar sodium chloride may be due to the hydration effect and the decrease in rate of tanning by the stronger sodium chloride solution and the sodium sulfate solutions to the aggregation factor. They are continuing their studies of the action of salts upon the vegetable tanning process.
Acid and Salt in Tan Liquors.
Tanners of heavy leathers usually attach much importance to the degree to which the skin is swollen, or plumped, during the tanning operation. It is generally assumed that greater yields of leather are obtained when the skin is tanned in a highly plumped condition. If | the plumping by means of acid is carried to excess, however, the skins will be ruined. The first sign of danger in this direction is a wrinkling and reticulation of the grain surface of the skin. A rapid tanning of the surfaces of the skin follows, rendering them almost impermeable to the tannin remaining in solution, and the fibers in the interior remain taw and swell considerably, assuming a glassy appearance. If left long in this condition, especially in warm liquors, the collagen hydrolyzes and the skin is damaged beyond hope of recovery.
TABLE XXXIII.
DEGREE OF PLUMPING OF CALF SKIN Propucep BY TAN Liguor CONTAINING 25 GRAMS OF OAK BARK ExtTrRAcT PER LITER AND Lactic ACID AND SopIUM CHLORIDE AS SHOWN IN THE TABLE.
Moles per Liter Gauge Readings in MM. Final Lactic Sodium (average of triplicates ) pH Value acid chloride Initial Final Ratio *.. “at 26°U None None 1.346 2.150 1.60 4.63 0.0025 bi 1.411 2.343 1.66 3.904 0.0050 ‘ 1.383 2.699 205 3.74
Wilson and Gallun** studied the-effect of acids and salts upon the plumping of calf skin in tan liquors, using their method, which is described in Chapter 8. The effect of lactic acid and of sodium chloride upon the degree of plumping of calf skin in a solution of oak bark extract is shown in Table XXXIII and in Figs. 125 and 126.
For this experiment a piece was selected from the butt of a calf skin, after liming, unhairing, and washing, of as nearly uniform thickness as possible and cut into squares having a side of about 2 centimeters. These were delimed by washing with several changes of 0.o1-molar hydrochloric acid containing 10 per cent of sodium chloride, then kept over night in a saturated solution of sodium bicarbonate containing 10 per cent of sodium chloride, washed thoroughly, and
finally bated for 5 hours at 40° C. ina solution of 1 gram per liter of pancreatin, having a pH value of 7.6. The pieces were then washed for 24 hours in running tap water and were kept under distilled water in a refrigerator at 7° C. until used. The resistance to compression of each piece of skin was measured by means of a Randall & Stickney thickness gauge with a flat, metal base, upon which the piece of skin was placed, and a plunger, having a circular base I square centimeter in area, capable of pressing on the surface of the skin under constant pressure. The gauge reading was taken, in every case, exactly two minutes after dropping the plunger onto the skin.
eepeoeOr o.0 4,0 4.5 O10 0,8 (016 Ok 0.5 pH Value of Tan Liquor Moles Sodium Chloride per Liter Fic. 125.—Effect of pH Value of Tan Fc. 126.—Effect of Sodium Chloride Liquor upon Degree of Plumping upon Degree of Plumping of Calf of ‘Calf Skin. Skin in Tan Liquor Acidified with
7 Eleven tan liquors were prepared as indicated in Table XXXII.
The gauge readings of pieces of the standard skin were taken and they were then shaken with water to bring them back to their normal shape, after being compressed in the gauge. They were then put into the tan liquors and allowed to remain there for 24 hours at 20°C. The final eauge readings were then taken. In each case 3 pieces of skin were put into 100 cubic centimeters of tan liquor and the agreement between the triplicate determinations was satisfactory. The degree of plumping caused by the liquor is measured by the ratio of the final to the initial gauge reading.
The actions of the acid and the salt are not exactly the same as they would be in pure water, but are complicated by the tanning action of the liquor, which decreases the swelling power of the skin. The general tendency of the acid, nevertheless, is to swell the skin and the action of the salt to counteract this swelling.
of various compositions. Unfortunately the pH values of the liquors were not determined and, in many cases, it is not clear how much of the change observed is due to variation of hydrogen-ion concentration.
Rapid Tannages.
Numerous accounts appear in the literature of attempts to hasten the tanning process, especially for heavy leathers. But few of these have yet developed to a point where the mechanism of the process is well defined. In many cases, it appears likely that the added accelerator acts only indirectly by bringing about a more favorable reaction of the tan liquor itself.
One process for hastening tanning that seems, on the face of it, to merit further investigation is that described by Cross, Greenwood, and Lamb.’* In the course of investigations on the hemi-celluloses of seed endosperms, the authors studied their compounds with tannin, which may be made to form apparently homogeneous jellies. From previous experience in the dyeing of silk, the authors conceived the idea of controlling the astringency of the tannin by using it in the form of a compound with the hemi-cellulose. They found that the use of “gum tragasol” in conjunction with the tannin solution caused a very rapid penetration of tannin into the skin. Complete penetration of very thick hides was obtained in two or three days, although the reduced rate of combination between collagen and tannin required the keeping of the hides in the liquor for a somewhat longer time than this.
formed of a starch solution.
Another process intended to hasten the tanning of heavy hides is that of C. W. Nance?” and known as the vacuum process. The hides are put into a tank, which is then evacuated to a pressure of 0.5 lb. per square inch. The temperature is then gradually raised to the point at which water boils at this pressure. The tan liquor is introduced and the temperature allowed to fall slowly to permit the hide to absorb tan liquor to replace the water lost by boiling. By a proper regulation of temperature and pressure as well as concentration of tan liquor, it is claimed that an enormous reduction in time of tanning can be effected. ;
Attempts have been made at various times to hasten the tanning process by the application of an electric current. The hides are placed between. carbon electrodes and the current turned on; in moving towards the anode, the tannins are thus made to penetrate the hide. Ridea] and Evans 18 pointed out that to get good results the conductivity of and ta ae Bos Colorin uthlauegs: © F: Crm G. Vs Greenwood
the liquor must be very low and that the cathodes should be made of carbon and the anodes of copper. Williams *® found that a direct current causes a rapid destruction of pure gallotannic acid, which did not take place when an alternating current was used. Following the presentation of Rideal and Evans’ paper, J. G. Parker said that he had experimented with electrical tanning and doubted that it had any advantages over systems not involving the use of the electric current. At any rate, it has not been adopted very widely as yet.
Much attention has been paid recently to the effect of adding organic compounds containing sulfonic groups to vegetable tan liquors upon the rate of penetration of the tan liquor into the hide. Among the materials commonly used may be mentioned the lignosulfonic acids obtained from the so-called sulfite cellulose, a by-product in the manufacture of paper from wood pulp, and also the synthetic products known as syntans, discovered by Stiasny, which will be discussed in Chapter 15. These materials act much like certain nontannins naturally occurring in vegetable tanning materials in lessening the astringency of the liquors and hastening the penetration of tannin into the skin.
Apparently they have lower molecular weights than the tannins, which enable them to diffuse into the skin more rapidly. Since they actually combine with the collagen, they retard the combination of the true tannins with collagen, which thus permits tannin to diffuse into the interior that would otherwise have combined with collagen at the outer surface. This makes them valuable materials to use in the early stages of tanning. Whether or not the sulfonic groups which they possess are harmful for some kinds of vegetable tanned leathers has been the subject of debate, but has not yet been clearly settled.
The acid character of these sulfonic groups gives the liquors a very low pH value, which in turn causes a lightening of the color of both the liquors and the leather. In some cases there seem to be combinations between the tannins and the sulfonic compounds, resulting in compounds less easily precipitable than the original tannins. The synthetic materials seem also to cause a reduction of some of the more highly oxidized tannins, which may explain in part the lesser tendency of certain mixtures to precipitate upon the addition of acid.
Theory of Tanning.
Until it became possible to treat the chemistry of the proteins in a quantitative manner, there was little hope of developing a quantitative theory of tanning. Numerous attempts to determine the relative combining weights of gelatin and tannin led only to variable and often apparently contradictory results because of the failure to appreciate the existence of uncontrolled variable factors. A review of the older Set on theories of tanning would be of little more than historical value.
development of the chemistry of the proteins. One school of thought treats the theory of tanning from the viewpoint of the physical chemistry of the proteins and the other from that of organic chemistry.
The line of investigation of the physical chemistry of the proteins started by Procter led naturally to the conception of the mechanism of tanning formulated by Procter and Wilson.2® The work leading to the formulation of this theory is given in detail in Chapter 5 and need not be repeated here. When in equilibrium with a tan liquor having a pH value lying in the range 2 to 5, collagen may be looked upon as constituting an aggregate of complex cations balanced by much simpler anions held in the solution immediately in contact with the collagen structure by the same forces that hold all oppositely charged ions together. We may assume that the collagen composing a hide fiber has a structure corresponding to that of gelatin when set to a jelly.
The theory may be pictured very simply by considering a piece of skin in contact with a solution containing only tannin and the acid HA. When equilibrium is established between the collagen and the acid, in the tan liquor let
The equilibrium conditions are exactly analogous to those described for gelatin, from which it is apparent that there will be an electrical difference of potential between the jelly phase and the external solution expressible quantitatively by : rope as log — RY oe oe VA
Each tannin particle is negatively charged and, consequently, must have associated with it an equivalent number of cations held in the solution immediately in contact with the particle, which we may call the surface film for convenience, although it makes no difference to the theory whether the tannin particle is solid, like a gold particle, or a jelly particle capable of absorbing solution. Let the concentration of these cations be represented by z, and the concentration of the anion A’ in the surface film by y,; the total concentration of cation then equals y, + 2,. The electrical difference of potential between the surface film and bulk of solution then equals
It is evident that E and FE, are of opposite sign.
According to the Procter-Wilson theory, the first important action in the mechanism of tanning results from the tendency for EF and FE, to neutralize each other. The initial rate of tanning will, therefore, be measured by the sum of the absolute values of the potential differences, or
In this expression, z is measured by the absolute value of the electrical charge on the collagen and 2, that on the tannin particles, while x represents the hydrogen-ion concentration of the tan liquor. For a fixed value of x, an increase in value of either zg or g, evidently causes an increase in the rate of tanning.
It is apparent that an increase in u, provided it does not increase z or 4, will cause a decrease in rate of tanning. This explains, in part, the retarding effect of salts upon the rate of tanning. If u is increased without limit, the value of the above expression becomes zero.
When the surface film surrounding the tannin particle has joined the solution constituting the jelly phase of the collagen and thus neutralized the potential difference which each had against the external solution, the actual charges on the collagen and tannin are free to neutralize , each other, as in the combination of any two oppositely charged ions which tend to form a slightly dissociated salt.
Like the physical chemistry of the proteins, outlined in Chapter 5, this theory is capable of almost indefinite extension by mathematical treatment. Since the quantitative testing of the theory has only just been begun, such extensions may well be left for some future time. It is worthy of note, however, that the theory has proved a valuable guide in the development of tanning processes and no facts observed in tanning practice have yet been shown to be out of harmony with it.
It is interesting to speculate on the probable combining ratio of collagen and pentadigalloyl glucose. Taking the author’s value of 750 as the equivalent weight of collagen and assuming that each digalloyl
radical is capable of combining with collagen, we arrive at a combining ratio of 340 parts of tannin to 750 parts of collagen, or 45.3 per 100 parts of collagen. It may be only a coincidence, but this ratio represents the minimum possible for vegetable tanned leather to pass as fully tanned, at least in the author’s experience. On the other hand, when skins are allowed to remain in the tan liquors for months, the ratio approaches the value of 90 parts of fixed tannin per 100 of collagen, but the author has never known it to pass this value in practice. Of course it is appreciated that different tannins may have different molecular weights, which would cause some deviation in the ratio to be expected. Any supposition as to the combining proportions of collagen and tannin is admittedly highly speculative in view of our meagre knowledge of the mechanism of tanning, but where so little is known, such speculations are valuable in forming a nucleus from which to build.
The Procter-Wilson theory does not concern itself with the constitutions of the collagen cation and tannin anion, nor does it deal with possible combinations of collagen and tannin where these have electrical charges of the same sign, a condition which rarely, if ever, occurs in tanning practice.
Thomas and Kelly 74 have recently started an investigation to determine the nature of the combination of collagen and tannin at different pH values. Trunkel ?* had previously shown that the waterinsoluble compound of gelatin and tannin can be resolved into its components by digesting with ethyl alcohol, provided the digestion is carried out before the precipitate has dried. After drying, the gelatintannin compound is unaffected by alcoholic digestion. Thomas and Kelly studied the effect of alcohol upon collagen tanned at different pH values.
Tan liquors were prepared having pH values of 1, 3, 5, 7, and 9. In the study of hemlock bark extract, portions of hide powder containing I gram of dry protein were shaken for 24 hours, at room temperature, with 50 cubic centimeters of tan liquor containing 2.7 grams of solid matter of the hemlock extract. The tanned powders were then filtered and washed in Wilson-Kern extractors until the wash water gave no color upon addition of ferric chloride. The wet powders were then transferred to Thorn extractors and extracted with g5-per cent alcohol. In this type of extractor, the material is extracted by the hot vapors as well as by the condensed solvent.
At intervals the alcoholic extracts were transferred to beakers, evaporated to dryness, dried for 4 hours im vacuo at 100° C. and weighed. After apparently complete extraction, the tanned powders also were dried im vacuo and weighed, the loss of tannin due to the alcohol extraction being calculated by comparison with a control series not treated with alcohol.
Table XXXIV shows the results obtained from weighing the residues from the alcoholic extracts and Table XXXV those obtained from the dry weights of the extracted leathers. Apparently alcohol decomposes most easily those leathers which were tanned at pH values lying between 3 and 5, the region in which tanning is usually done in practice. It is also apparent that leathers tanned at pH values greater than 5 are much more resistant to decomposition than those tanned at values less than 5. Table XXXV also shows the effect of extracting previously dried leathers with alcohol; drying evidently brings about a more permanent fixation of the tannin.
ExtTRACTION BY ALCOHOL OF FIXED TANNIN FROM LEATHERS TANNED WITH Hemiock Bark Extract AT DIFFERENT pH VALuges. Ficures OBTAINED BY WEIGHING THE Dry RESIDUES FROM THE ALCOHOLIC EXTRACTS.
a ee eee 0.6 0.0
A curious finding is that the figures in Table XXXV show a smaller loss of tannin than those in Table XXXIV. Some light is thrown upon this difference by a series of experiments with gambier. These were similar to the hemlock series except for the fact that the 50cubic centimeter portions of tan liquor contained 2 grams of dry gambier solids. Table XXXVI shows the results obtained by weighing the dry leathers after extraction with alcohol. The leather tanned at a pH value of 9 actually shows a gain in weight upon extraction with alcohol. Thomas and Kelly suggest the hypothesis that this gain may be due to an oxidation of the alcohol to aldehyde followed by an
that oxidized tannins present in leather cause an oxidation of unsaturated oils used in fatliquoring leather, as determined by the ratio of oxidized to unoxidized fatty acids subsequently extracted from the leather. It is therefore not unreasonable to suppose that tannins which have been oxidized at a pH value of 9 may be able to bring about an oxidation of the alcohol molecule.
EXTRACTION By ALCOHOL OF FIXED TANNIN FROM LEATHERS TANNED WITH GAMBIER EXTRACT AT DIFFERENT pH VALUES. FIGURES OBTAINED BY WEIGHING Dry LEATHERS AFTER THE ALCOHOL EXTRACTION.
The most important finding in this work is that the kind of fixation of tannin by collagen at pH values lower than 5 is different from that at pH values greater than 5. The simple theory of Procter and Wilson does not take into consideration the complex organic reactions which apparently occur in tanning with liquors having a pH value greater than 5, nor the changes in the collagen-tannin compound which take place upon drying and aging.
Oxidation Theory.
Of the various theories of tanning treating the subject from the standpoint of organic chemistry, the oxidation theory supported by Meunier, Fahrion, and others is the only one meriting serious consideration. Meunier ** and his co-workers found that skin could be converted into leather by bringing*it into contact with a solution of benzoquinone. The color of the skin changed successively to light rose, to violet, and to brown. A leather of remarkable resistance to boiling water was obtained. An observation of great theoretical significance was that a portion of the quinone was reduced to quinol during the tanning action. Meunier concluded that part of the quinone had been reduced by the oxidation of the collagen and that only the oxidized collagen entered into combination with the remaining quinone. He likened the action to that of quinone upon aromatic amines:
Although the tanning of skins by means of chromium salts is only of comparatively very recent origin, a large proportion of the world’s supply of light leathers is now tanned by this process. In 1858 Knapp? described a process for tanning skins with salts of aluminum, iron, and chromium, but chrome tanning did not come into prominence commercially until after the appearance of the patents of Augustus Schultz, of New York, in 1884. In Schultz’s process, the skins, after bating or deliming, were tumbled in a solution of potassium bichromate and hydrochloric acid until the chromate had completely penetrated the skins, after which they were allowed to drain. They were then tumbled in a solution of sodium thiosulfate acidified with hydrochloric acid, which reduced the chromate to chromic salt, in which condition it combines with the skin protein, yielding a very stable leather.
Schultz’s system of tanning is known as the two-bath process. In 1893 Martin Dennis patented a system for tanning skins directly in a solution of basic chromium chloride along the lines suggested by Knapp in 1858. This one-bath process was naturally to be preferred to the two-bath process and soon gained precedence over it, except in the manufacture of glazed kid leathers, where the two-bath process seemed to yield a leather having more desirable properties. No explanation has yet been forthcoming as to why this should be so, although the author believes that the same results can be obtained by the one-bath process, if the reaction of the liquor is made to equal that of the liquor present in the skins during the second bath of the two-bath process. In the ordinary two-bath process, the acidification of the sodium thio-. sulfate causes a deposition of sulfur in the leather, which affects its properties, but a similar result can be obtained by the use of sodium thiosulfate in the one-bath process. On the other hand, the precipitation of sulfur in the two-bath process can be avoided by using sodium bisulfite as the reducing agent. Basic chromium sulfate was found to be superior to the chloride for one-bath tanning, as well as cheaper, and is now almost universally used. |
CHROME TANNING 279
by Procter? in which acidified sodium bichromate solution is reduced to chromic salt by the addition of a solution of glucose. A great variety of reducing agents have since been suggested or patented for the purpose. A very convenient method, described independently by Balderston * and Procter,* consists in passing sulfur dioxide gas into a solution of sodium bichromate until the reduction is complete. The equation usually given for the reaction is as follows:
end product probably being much more complex than this.
In modern practice, it is customary to pickle the skins from the beamhouse before chrome tanning, as described in Chapter 10. This has the advantage of bringing all skins into a uniform condition. After pickling, the skins are put either into a drum or a paddle vat and tumbled or paddled with chrome liquor until completely tanned, which condition is determined by placing a cutting in boiling water. Any untanned portions are converted into gelatin and this causes the piece of skin to shrivel up and curl. When the skin is completely
tanned, it is apparently entirely unaffected by boiling water. The rate
of penetration of the chromium salts into the skin, the rate of tanning, and the properties of the resulting leather are markedly influenced by changes in concentration of chromium salt, neutral salt, and hydrogen ion. Conditions are made even more complex by the important effects of time, temperature, and degree of hydrolysis of the chromium salts. All of the variables must be adjusted to suit each other as well as the condition of the skin as it enters the tan liquor and the processes to which it is to be subjected after tanning. Probably no two tanneries operate exactly alike and very few would dare to deviate far from the practice found to give good results under their particular conditions of operation. .
Chromium Collagenate.
It now seems fairly well established that acid and basic radicals form definite salts with proteins. There is nothing novel about the assumption that chromium, or other metallic radical, can form with collagen a series of salts that might be called chromium collagenates. Moreover, such an assumption is a convenient one, even though it may be shown later that the compound formed is much more complex than would be indicated by the term chromium collagenate.
convert I00 grams of collagen into the chromium salt would be (152x 100)/(6x 750), or 3.38 grams. Lamb and Harvey ® found that chrome leather showing less than 2.8 to 3.0 per cent of chromic oxide, based on the dry leather, was invariably undertanned. Based upon actual collagen, the figure would be about 3.4. That the figure 3-38 has some significance will be made more apparent later. This value assumes that all of the three bonds of the chromium ion have entered into combination with the protein and we should expect such a compound to be extremely stable, which chrome leather undoubtedly is.
The most exhaustive studies yet made of the combination of collagen and chromium at measured concentrations of hydrogen ion, chromic oxide, and neutral salt are those of Thomas and his collaborators, which will be given in some detail.
Hydrolysis of Chromium Salts.
Being a salt of a strong acid and a weak base, chromic sulfate hydrolyzes to a very considerable extent in aqueous solution, yielding free sulfuric acid and a series of basic chromic sulfates. Thomas and COMMERCIAL CHROME DIQUOR) Baldwin ® = fol ae change in
immediately degree of hydrolysis of chromic salts, under various conditions, by measuring changes in hydrogen-ion concentration. Studies were made of solutions of C.P. chromic sulfate and chromic chloride and also of a typical commercial chrome liquor, which showed by analysis: Cr.Onz, 14.3 per cent; Fe.O3, 1.9 per cent; immediately Al,Os, 0.2 per cent; SOs, 23.5 per cent; Cl, 0.2 per cent; and = ba= sicity corresponding to the formula Cr(OH)1.2(SOu)o.9, the sulfate
LO. 8720 “320 M46 dium sulphate. Grams Cro0z per Liter Effect of dilution: Fig. 127 Fic. 127.—Effect of Dilution upon the shows the pH values of both chro-
trations. Strong solutions of each were diluted to increasing extents and the hydrogen-ion measurements were made immediately and also after the diluted solution had stood for 7 or 9 days. With both mate-
rials, the effect of dilution is naturally to raise the pH value, but, upon standing, the pH value of the commercial liquor continues to rise, while that of the chromic sulfate falls.
‘Effect of added acid or alkali: Fig. 128 shows the effect of adding sulfuric acid or sodium hydroxide to solutions of the commercial chrome liquor and of pure chromic sulfate. In each case a given amount of concentrated chrome liquor was mixed with a definite volume of standard sulfuric acid or sodium hydroxide and the mixture was diluted to 50 cubic centimeters. The hy-
drogen-ion concentration was deter- COMMERCIAL mined immediately after mixing 4,0 ane and diluting and also after definite |
length of time; after the addition of B 4,5 acid, the hydrogen-ion concentra- 4 eer: tion continues to fall for many days, « a SULFATE approaching, but never reaching the § 3,5 ot value it had before the addition of & the acid. & 3,0 ‘ The lowering of the hydrogen- & ae ion concentration by the addition of 7*® a alkali causes an increase in the de- 2,0 Shlemaetietats gree of hydrolysis of the chromium - a eee
salt and the hydrogen-ion concen- 1B EL tration continues to rise towards the = | ~ _ | after 30 de; value it had before adding the a alkali. The long time required for such systems to reach equilibrium, after a disturbance, increases the difficulty of investigations of the BG «Add ed’ 0. 2M 1p 20¢00x ua0H chemistry of chrome tanning. og. c ae ee eee eee ° rams Chromic Oxide
Effect of neutral salts: In 5, 128 Rffect of Added Acid or Chapter 4 it was pointed out that Aitatin unde tain Ledeen ae the hydrogen-ion concentration of Chrome Liquors. acid solutions is increased by the addition of neutral chlorides and decreased by the addition of neutral sulfates. The effect of increasing concentration of different salts in solutions of sulfuric and hydrochloric acids was shown in Figs. 39 and 40. In Fig. 129 are shown the changes in hydrogen-ion concentration occurring when various salts are added to solutions of the commercial chrome liquor and of pure chromic sulfate. The curves are strikingly similar to those in Figs. 39 and 40. The time effect is shown in the case of sodium chloride; the other measurements were made 30 days.
equilibrium.
In order to avoid the complications obtained by mixing chlorides with chromic sulfate, Thomas and Baldwin also studied the effect of neutral chlorides upon a solution of pure chromic chloride. Fig. 130 shows the effect of adding increasing amounts of various neutral salts
Chrome Liquors Containing 13.86 Grams of Chromic Oxide per Liter.
to a solution of the green modification of chromium chloride; measurements of hydrogen-ion concentration were made immediately after adding the salt and diluting to definite concentration and also after the solutions had stood for 50 days. Where no salt was added, there was a rise in pH value upon standing.
The complex nature of the time effect after adding salt to a chrome liquor is shown in Fig. 131. Commercial chrome liquor and sodium chloride were mixed and diluted so that the final concentration of sodium chloride was twice molar and of chromic oxide 13.86 grams per liter. Determinations of hydrogen-ion concentration were made every
all neutral salts‘and that sulfates are even more effective than chlorides. ‘he amount of alkali required to start precipitation in a chrome liquor was determined by titrating 10 cubic centimeters of filtered liquor with o0.IN sodium hydroxide until the first permanent turbidity appeared, as seen by looking through the liquor. tor a given chrome liquor, 3.7 cubic centimeters of standard alkali were required. To another portion of 10 cubic centimeters was added 0.04 gram molecule of sodium chloride; in this case 6.8 cubic centimeters of the standard alkali were required to start precipitation. Kepeating the experiment, taking in each case 10 cubic centimeters of the chrome liquor and 0.02 gram molecule of added salt, the following amounts of standard alkali were required to start precipitation in the presence of the neutral salt indicated: none, 3.7; KBr, 3.9; KCl, 40; KNO,, 4.2; NH Cl ais Nace 5-4; MgCh, 0.2; MgsO,, 10.5; NazsO,, 11.4; and (NH,)25O,, 11.6. cit least some of the effect ot the chlorides may be attributed to their action in increasing the hydrogen-ion concentration of the liquor. ‘lhe sulfates, however, decrease the hydrogen-ion concentration, but, since they increase the stability of the chrome liquor, it seems likely that they form addition compounds with the chromium salt less easily precipitated than the simpler salt.
Diffusion of Chromium Salts into Protein Jellies.
In vegetable tanning, the rate of diffusion of tannin into the fibers of the skin increases with increasing pH value. In chrome tanning, the reverse is true. An increasing pti value causes the molecules of chromium salt to form aggregates ot increasing size, greatly reducing the rate at which they dittuse into the skin.
When neutral skin substance is brought into contact with a chrome liquor, both the free acid present in the liquor and the basic chromic sait begin to dittuse into it. But the greater rate of diffusion of the acid causes the liquor to become more basic. Procter and Law +¥ studied the relative rates of dittusion of the free acid and chromium salt of a chrome liquor into gelatin jelly by allowing a faintly alkaline solution of gelatin and phenolphthaiein to set in a Nessler tube and pouring the chrome liquor on top of the jelly. As the acid diffuses into the jelly, it discharges the color of the phenolphthalein, while the extent ot diffusion of the chromium salt:can be followed by its color the combination of both acid and chromium with the gelatin has a retarding eftect upon the rate of diffusion. )
this differential diffusion may not occur where the common practice of pickling skins prior to tanning is used. When the skins contain a great excess of acid, the chromium salt diffuses into them very rapidly but the rate of combination of chromium and collagen is corresponding! agers and : becomes necessary to neutralize some of the acid Rees the skins can become completely tanned meated by the chromium cai » oven note ee ea
The Time Factor in Chrome Tanning.
The progress of the chrome tanning of hide powder with time has been studied by Thomas, Baldwin, and Kelly.11 12 They first examined the action of the commercial chrome liquor described above. The chrome liquor was diluted to contain 17 grams of chromic oxide per liter. Two hundred-cubic centimeter portions were poured upon 5-gram portions of hide powder in glass-stoppered bottles. These mixtures were kept at room temperature (about: 20-00: ); agitated frequently, and Gltered off at definite intervals,—1, 2, 4, 6, 8, 12, 24, 48, 72, and 96 hours. They were filtered by suction on a dry paper in a Buchner funnel, the Gltrate was set aside for analysis, and the tanned powder was washed with 500 cubic centimeters of water in order to remove chromium salts
The filtered liquors were analyzed for hydrogen ion, acidity, and chromic oxide and the tanned powders for sulfate, chromic oxide, ash, and hide substance (nitrogen x 5.62).
Measurements of hydrogen-ion concentration were made immediately upon filtration of the liquors and, in order to exclude the possibility of attributing natural hydrolytic changes to absorption by hide substance, parallel measurements were made upon a portion of the chrome liquor having no contact with hide powder. The parallel sets of measurements are shown in Fig. 132.
In Fig. 133 are shown the amounts of chromic oxide and of sulfate combined with 1 gram of skin protein at different intervals of time. These were obtained from the analyses of the washed powders after tanning. The broken lines represent calculations made from analyses of the chrome liquors on the assumption that the concentration is uni-
form throughout all of the solution present in the system during tanning, We know from Chapter 5 that this assumption is not true, that the solution absorbed by the collagen jelly is less concentrated than the outer solution. This explains why these curves show lower values for combined sulfate and chromic oxide. Thomas and Kelly were well aware of this fact and presented the calculations made from the analysis of the solutions for the purpose of demonstrating the fallacies in this
Liter.
method, which is commonly used for measuring the extent of “adsorption” of substances from solution by skin and other materials. The discrepancy is increased in the case of the sulfate determination by the fact that some combined sulfate is removed by washing, whereas the chromium-collagen compound is very stable. |
They next .studied the action of a solution of pure chromic sulfate, but, using the same procedure, got only erratic results. They found it necessary, when using the pure salt, to soak the hide powder in water before adding the chrome liquor. The fact that the pure salt gave a solution very much more acid than the commercial salt may have had something to do with this. Five-gram portions of hide powder were
placed in each of a series of glass-stoppered bottles, 50 cubic centimeters of water were added to each, and the powders were allowed to soak over night. Then 150 cubic centimeters of chromic sulfate solution were
added, making 200 cubic centimeters of liquor with a concentration of 16.4 grams of chromic oxide per liter. The rest of the experiment was performed just as in the case of the commercial chrome liquor, except for the fact that a time period of 64 days was covered.
The variation in hydrogen-ion concentration in the control liquor and in the filtrates from the tanning tests is shown in Fig. 134. The trend of the curves is different from that of those in Fig. 132.
The amounts of chromic oxide and of sulfate combined with 1 gram of hide substance are shown in Fig. 135. When the calculations were. made from the analyses of both leathers and liquors, the same sort of differences were noted as with the commercial chrome liquor. The only reliable figures are those obtained from the analyses of the leathers, shown by the continuous lines. The amount of chromic oxide combined with 100 grams of hide substance approaches a limiting value of 13.8 grams. Because this is almost exactly 4 times the author’s value of 3.38 grams, calculated to be the smallest amount of chromic oxide required to convert 100 grams of collagen into the chromium salt, Thomas and Kelly referred to it as tetrachrome leather.
A comparison of Figs. 133 and 135 will show that the rate of tanning is very much less in the chromic sulfate solution, in which the hydrogenion concentration is about 20 times as great as in the commercial liquor. It will also be noted that the amount of chromic oxide combined with I gram of skin protein is greater for the commercial liquor after 4 days than the limiting value in the case of the pure chromic sulfate and has not reached a limiting value in 4 days. The significance of this will be made more apparent presently.
The effect of the concentration of a chrome liquor upon the fixation of chromium by skin protein has been studied by Baldwin ** and by Thomas and Kelly.***° A solution of the commercial chrome liquor, described above, was made having a concentration of 202 grams of chromic oxide per liter and this was used at various dilutions to study the effect of concentration. A 200-cubic centimeter portion of each dilution was poured into a bottle containing hide powder equivalent to 5 grams of water-free hide powder. Another portion of each solution was set aside and at the expiration of 48 hours the hydrogen-ion concentration was determined. The bottles were shaken at intervals for 48 hours and the contents were then filtered off by suction. Analyses were made of the liquors and of the tanned powders after washing and drying, the methods employed being the same as in the studies of the time factor. ,
Fig. 136 shows the variation in hydrogen-ion concentration in the filtrates and also in the control liquors which had no contact with hide powder. Fig. 137 shows the effect of concentration upon the amount of chromic oxide fixed by 1 gram of skin protein in 48 hours. Where the calculation was made from the analyses of the liquors, a ridiculous result was obtained, as expected. In this calculation it is assumed that the decrease in concentration of the liquor represents the amount of solute combined with the hide powder, but the concentration of the stronger liquors is actually increased by the introduction of hide powder,
Increasing Concentration.
due to the absorption of a greater proportion of water to chromium salt than existed in the solution before the introduction of the hide powder. It is interesting to note that the method of calculation giving these ridiculous results is the same in principle as that of the official method of tannin analysis of the American Leather Chemists Association, described in Chapter 12. The determination of combined chromium by analysis of the washed leathers corresponds to the Wilson-Kern method of tannin analysis, also described in Chapter 12.
The reason for the point of maximum at a concentration of 15 grams of chromic oxide per liter is not entirely clear, although a number of causes may be assigned to the falling off in rate of combination at higher concentrations, among which may be mentioned the increasing hydrogen-ion concentration, as shown in Fig. 136, the increasing salt concentration, and the probability of the formation of addition com-: pounds, It is interesting to compare this curve with those for the rate
ter 13.
The experiments just described were repeated exactly, except for the fact that the hide powders were kept in the chrome liquors for 8.5 months. The results are shown in Fig. 138. Curiously enough a point of maximum occurs having a value of 26.6 grams of chromic oxide per 100 grams of skin protein, which is approximately 8 times the author’s calculated minimum of 3.38. Moreover a point of inflection occurs in the curve at a point giving just half of the maximum value. On the
Chromium with Hide Substance.
assumption that they had obtained octachrome collagen, Thomas and Kelly calculated the combining weight of collagen as 94, a value of the same order of magnitude as those of the amino acids making up the protein molecule. This degree of combination of collagen and chromium is the highest ever reported in the literature.
The fact that only a tetrachrome collagen was obtained after 64 days of contact with chromic sulfate solution, whereas an octachrome collagen was obtained with the commercial chrome liquor may possibly be explained by the differences in hydrogen-ion concentration of the two series of liquors. On this assumption, only half of the total number of carboxyl groups are capable of attaching chromium bonds at the higher acidities. The possibility is thus suggested that a series of collagen salts from monochrome to octachrome might be obtained by tanning hide powders for a sufficient length of time at different pH
tanned hide powder does not lose any measurable amount of chromium upon several hours’ washing, they decided to allow tetrachrome collagen to remain in contact with solutions of varying chromium content for several months.
.Chromium and Sulfate with Tetrachrome Collagen.
Portions of tetrachrome collagen containing just 5 grams of hide substance were placed in a series of 12 bottles and covered with 200cubic centimeter portions of chrome liquor of various concentrations. The bottles were kept sealed to prevent evaporation and were shaken once a week. At the end of 8.5 months the contents were filtered and
the powders washed free from soluble matter, dried, and analyzed. The results are shown in Fig. 139. They show that a hydrolysis of the chrome collagen and collagen sulfate compounds takes place in water and in very dilute chrome liquor, which was also shown by an increase in hydrogen-ion concentration.
With further increase in concentration of the chrome liquor, there is a steady addition of Cr,O; and SOs, approaching the condition of octachrome collagen. But with further increase in concentration the
curve does not fall below the tetrachrome value. This shows that the curve in Fig. 138 does not represent the equilibrium condition of a reversible reaction. On the contrary, it suggests that the fall in the curves is due to the increasing hydrogen-ion concentration, which inhibits the combination of collagen and chromium.
Effect of Neutral Salts upon Chrome Tanning.
In studying the effect of neutral salts upon the chrome tanning of calf skin, Wilson and Gallun 1° selected sodium sulfate and the chlorides of ammonium, sodium, lithium, and magnesium because of their different degrees of hydration in aqueous solution. The commercial chrome
Fig. 141.—Strips of Chrome Leather, All Originally of Equal Area, Taken After Tanning for 24 Hours and Then Boiling in Water for 5 Minutes and Drying. Compare with Curves in Fig. 140.
mixture which they used showed by analysis: Cr2Os3, 24.2 per cent; Fe,Os;, 0.6 per cent; Al,Os, 2.7 per cent; SOs, 39.5 per cent; Cl, 0.4 per cent; and basicity corresponding to the formula Cr(OH)1.4(SO.)o.s. Solutions of this chromium preparation were mixed with solutions of the various neutral salts so as to give liquors containing 17 grams of chromic oxide per liter and definite quantities of salt.
In each test a strip of pickled calf skin, 16 square inches in area, was covered with 200 cubic centimeters of chrome liquor, in a bottle, and shaken at intervals for 24 hours. The pieces of skin were then washed by shaking with successive changes of water until the wash water gave only a very faint test for chloride or sulfate. Strips of equal area were cut from each piece and immersed in boiling water for 5 minutes, in order to determine the nearness to complete tannage. The remaining portions were cut into small pieces, dried and analyzed. The effect of increasing concentration of the chlorides of ammonium, sodium, lithium, and magnesium upon the amount of chromic oxide combined with a unit of hide substance in 24 hours is shown in Fig. 140. In Fig. 141 are shown the strips of skins after being subjected to the action of boiling water for 5 minutes. The appearance of these strips parallels the curves, in a rough sort of way; that is, they generally show the greatest shrinkage in area where the amount of combined chromic oxide is smallest. The first strip in each series proved to be fully tanned and showed no shrinkage in area.
In another series of tests, chrome liquor having a concentration of 10 grams of chromic oxide per liter was used and the effect of sodium sulfate was studied in addition to the effect of the chlorides noted above. The results for the chlorides were practically the same as in the first experiment, except for the observation of a point of minimum in the sodium chloride curve at 2 moles per liter of salt and a slight rise to 3 moles. In the case of the sodium sulfate, there was a steady drop in fixation of chromic oxide from 10.09 grams per 100 of hide substance when no added salt was present to 3.57 when the solution was saturated with the salt.
Wilson and Gallun attributed the action of the chlorides, in part, to their hydration. The removal of .water from the réle of solvent would have the practical effect of increasing the concentration of all of the constituents of the chrome liquor, expressed in terms of the free solvent. Fig. 137 shows that increasing the concentration of the chrome liquor from 17 grams of chromic oxide per liter does retard the rate of combination of collagen and chromium. That the chlorides actually concentrate the solute in the free solvent is also indicated by the fact that they increase the hydrogen-ion concentration as measured by the hydrogen electrode. But at half-molar concentration the effect. only of magnesium chloride is in its expected relative position; being most highly hydrated it should produce the greatest effect, which it does. At 3-molar concentration all 4 chlorides are in an order inverse to that expected unless it may be assumed that at very high concentrations of chrome liquor a further increase in concentration causes an increased rate of tanning.
The action of sulfates is in a category different from that of the chlorides, as shown by the fact that they decrease the hydrogen-ion concentration of acid solutions and of chrome liquors. Wilson and Gallun suggested that the retarding action of sodium sulfate was probably due to the formation of addition compounds between the added salt and the chromium compounds which tan less readily than the original chromium compounds, but that the action was further complicated by the hydration of the sodium sulfate.
In the hope of throwing further light on this complex action, Thomas and Foster 2“ studied the actions of sodium chloride, sodium sulfate, and sucrose upon chrome tanning. They prepared a pure chrome liquor by reducing pure sodium bichromate with sulfur dioxide and then expelling the excess of this gas. Portions of hide powder equal to 5 grams of hide substance were covered with 50 cubic centimeters of
water in bottles and allowed to stand over night, when the salt or sugar to give the desired concentration was added. Finally 150 cubic centimeters of chrome liquor were added, of such concentration that if it were diluted to 200 cubic centimeters it would contain 3, 15.5, or 100 grams of chromic oxide per liter. The mixtures were rotated in a tumbling machine for 48 hours, filtered through muslin bags, and washed well with tap water and 3 times with 200-cubic centimeter portions of distilled water. The washed powders were then dried and analyzed as usual.
The effect of increasing concentration of sodium sulfate, sodium chloride, and of sucrose is shown in Fig. 142. Analysis of the filtrates from the series of chrome liquors of intermediate concentration showed that increasing concentration of sodium chloride lowered the pH value from 2.90 to 2.20, while sodium sulfate raised it to 3.01. This contrasting effect is similar to that shown in Fig. 120. |
The curves representing the effect of sodium chloride all have points of minimum followed by an upward trend, which, in the case of sodium sulfate, is shown only where the chrome liquor is very concentrated. But sucrose is evidently without effect, except at 4-molar concentration.
Because sucrose, which is hydrated in aqueous solution, shows no retarding effect upon chrome tanning up to 3-molar concentration, Thomas and Foster concluded that the retarding effect of the salts is probably due to some cause other than their hydration. They suggested that chlorides, as well as sulfates, form addition compounds with chromium salts rendering them less dissociated and, consequently, less active in combining with the skin protein. They liken the action to the decrease in toxicity of mercuric chloride in the presence of sodium chloride, which Rona and Michaelis '* ascribe to the formation of the complex ions HgCl,;’*and HgCl,’”.. Upon increasing the concentration of salt still further, the hydration effects a virtual concentration of the chromium ions to such an extent that the retarding action of the addition compound formation is counterbalanced by the activity of the high concentration of chromium ion and the curves begin to slope upward.
It may be questioned as to whether we are safe in drawing conclusions regarding the effect of hydration from the experiments with sucrose. Corran and Lewis *® found that potassium and chloride ions are soluble in the water of hydration of sucrose. The effect of neutral salts upon the hydrogen-ion activities of acid solutions, described in Chapter 4, seem to indicate that ions are not soluble in the water of hydration of salts. Thomas and Foster ascribe the retardation of chrome tanning by 4-molar sucrose to the formation of a compound with chromium, analogous to the combination with other hydroxy compounds, such as tartrates. As will be shown presently, such compounds of chromium have no tanning power. :
While investigating the failure of certain types of chrome liquor to tan pickled calf skin, Procter and Wilson *° found that the tanning action is checked and may even be reversed by the introduction of salts of hydroxy-acids into the chrome liquor.
After the addition of Rochelle salt (potassium sodium tartrate) to a chrome liquor, a change occurs in the liquor which requires a considerable length of time for completion. Immediately after the addition, the chrome liquor is still precipitable by alkali, but the precipitate slowly redissolves with time. If the liquor is allowed to stand for several hours before the addition of alkali, no precipitate forms at all. A color change in the liquor is also noticeable.
A chrome liquor was made by rendering a solution of chrome alum basic with sodium carbonate and from this a series of solutions was prepared having a concentration of 13 grams of chromic oxide per liter and Rochelle salt in concentration ranging from zero to 50 grams per liter. A piece of calf skin was put into each solution, which was agitated occasionally for 24 hours. At the end of this time, all pieces in solutions containing 10 grams per liter or less of Rochelle salt were completely tanned, as determined by the boiling test, but those in the stronger solutions were not. ‘These solutions all gave precipitates upon addition of sodium carbonate; that containing 25 grams of the salt per liter gave a slight precipitate and that containing 50 grams gave none. The piece in the solution containing 25 grams became tanned after the addition of sodium carbonate but that in the solution containing 50 grams could not be made to tan, regardless of the amount of alkali added. That the action of the Rochelle salt was on the chromium salts and not on the skin was proved by washing the skin that was still not tanned and placing it in a liquor containing no Rochelle salt, in which it quickly became fully tanned.
The same results were obtained when the experiment was repeated with sodium citrate. The sodium salts of lactic, gallic, and salicylic acids were also found to prevent the precipitation of chrome liquor by alkali. Procter and Wilson attributed the action of Rochelle salt to the formation of a complex chromi-tartrate ion analogous to the cupri-tartrate ion of Fehling’s solution.
The fact that Rochelle salt will dissolve precipitates of chromic hydroxide led Procter and Wilson to suspect that it might have the power to decompose chrome leather. They soaked a piece of fully tanned leather in a normal solution of Rochelle salt over night and found, next day, that it would not stand the boiling test. But after washing and soaking in fresh chrome liquor, containing no Rochelle salt, it soon became fully tanned again. It was found that chrome leather can be detannized by Rochelle salt solution and then tanned again in fresh chrome liquor repeatedly, showing that chrome tanning is a reversible action, under certain conditions.
The extent to which chrome leather can be freed from chromium by Rochelle salt was shown by soaking a piece of chrome leather in a normal solution of Rochelle salt for two weeks. The solution was colored a deep green and the skin, after thorough washing, was found to be practically free from chromium and resembled a piece of bated skin. Upon heating with pure water, it was gradually converted into gelatin and the solution set to a firm jelly upon cooling. This work has since found application in preparing chrome leather wastes for manufacture into glue and jor the stripping of the chrome from the surface of leather to be retanned with vegetable tanning materials.
Comparison of Chrome and Vegetable Tanned Leathers.
Ever since chrome tanning was first introduced, the relative merits of chrome and vegetable tanned leathers have formed the subjectmatter for debate. Too often, however, the attempt was made to compare a poor grade of one kind of leather with a good grade of the other, without taking into consideration differences in the original skins and in the methods of manufacture of the leathers. Since the resistance of a leather to tearing, for example, is a function of the grease content, the moisture content, and the extent to which the thickness of the original skin has been reduced by splitting, any comparison between two kinds of leather must take all of these factors into consideration. There are, however, certain differences between chrome and vegetable tanned leathers that are incontrovertible and more or less independent of the details of manufacture. These only will be considered in making the comparison. | rie
Figs. 143 and 144 represent vertical sections of vegetable and chrome tanned leathers made from the same skin. After bating, the skin was cut into halves along the line of the back bone. One half was tanned with chrome liquor and the other with vegetable tanning materials. When finished, each leather represented an excellent specimen of shoe upper leather of its particular kind. The sections shown in the figures are from the finished leathers and were cut from exactly corresponding points on the skin. a
The outstanding difference in appearance is the much larger size of the fibers of the vegetable tanned leather. In the chrome tanned leather, the fibers are thin, as in dried, raw skin, but in the vegetable tanned leather, the fibers have grown to such an extent that they almost completely fill the interfibrillary spaces. But this difference in size of the fibers is only what one would expect from the fact that 100 grams of skin protein combined with 57.0 grams of tannin, in the case of the vegetable tanned leather, as. against only 7.2 grams of chromic oxide, in the other. This difference is responsible for the greater weight and solidity of vegetable tanned leather. Either leather can be made tough and as soft as desired by the introduction of a sufficient amount of oil, but the vegetable leather is capable of
empty. :
Another outstanding difference between the two kinds of leather is the relatively high sulfuric acid content of the chrome tanned leather compared to the negligible amount present in the vegetable leather. This particular sample of leather showed by analysis 6.65 grams of sulfuric acid per 100 grams of skin protein, which is typical of leathers of this type on the market. It should be recognized, however, that this sulfuric acid is not entirely free, but is combined either with the chromium compounds or with the skin protein. Only a trace of acid is free at any one time, but as soon as this trace is removed by washing with water, more is immediately liberated by hydrolysis.
Attempts to free chrome leather from sulfuric or other mineral acid, without damaging the leather in some way, have not been successful, so far as the author is aware. Reducing the content of sulfuric acid much below that normally occurring in chrome leather seems to cause brittleness, although the cause of this is not known. In making comparative tests, the author has always found shoes made from vegetable much more comfortable, especially on long walks, than shoes from chrome leather and has attributed at least part of this difference to the hydrolyzable sulfate present in the chrome leather.
The rise of chrome tanning has been favored by its speed and comparative simplicity. The manufacture of vegetable leathers requires a much longer time and more labor. In the manufacture of light leathers, not sold by weight, tanners have naturally preferred to switch to the quicker method of tanning with chromium salts, although some of the best grades of upper leather are still tanned with vegetable ‘tanning materials. In the manufacture of heavy leathers, sold by weight, tanners have been forced to adhere to the older method of vegetable tanning in order to get profitable yields. Incidentally, the author believes that they also get better leather. |
In Fig. 145 is shown a vertical section of chromed tanned horse hide, which should be compared with Fig. 105, of Chapter 13. Both of these sections are from corresponding points of the same hide, which was cut in two after bating, half being tanned in chrome liquor and half in vegetable tan liquors, as in the experiment with calf skin. The difference between the two kinds of tannage is even more noticeable here.
Fig. 146 shows a fine specimen of chrome tanned goat skin, such as is used in making kid shoes. Fig. 147 represents an unusually fine specimen of ooze, or suede, leather. This leather is worn with the flesh side out, which gives it a velvety appearance. For the best grades, only slink skins are used because these are usually free from the blood vessels which are ordinarily abundant at the flesh boundary of the skin and detract from the appearance of leather finished on the flesh side. In comparing the various sections, any differences in magnification noted must be taken into consideration.
The simplest theory of chrome tanning is that it consists of the combination of chromium and collagen, forming a series of salts that might be called collagenates of chromium. From this chemical theory, there are theories of many shades and kinds all the way down to the assumption that chrome tanning consists of a precipitation of colloidal chromic oxide upon the surfaces of the skin fibers.
In following chrome tanning by means of the microscope, the author has observed the chrome liquor diffuse into the skin and also into the substance of each fiber, but without any visible sign of precipitation. When tanning was complete, each fiber looked like a transparent rod of green glass. This is similar to the phenomenon observed in vegetable tanning.
Thompson and Atkin ** recently attempted to apply the ProcterWilson theory of vegetable tanning to chrome tanning. The electrical charge on the collagen may be accepted as positive during chrome tanning and it seemed improbable to Thompson and Atkin that combination takes place between positively charged collagen and a positively charged chromium ion or complex. In a review of 80 papers dealing with chromium salts, they found numerous contradictions on points of importance, but one fact seemed to stand out as definitely established. Chromic sulfate exists in solution in two modifications, one green, the other violet.. At any temperature between 0° and 100° C., a definite equilibrium exists between the two forms in solution, the green being more stable at high and the violet modification at lower temperatures. In the change from violet to green by raising the temperature, equilibrium is quickly reached, but in the reverse action, following a lowering of the temperature, equilibrium is reached only after a long time. Thompson and Atkin offered the theory that chrome tanning is effected by an anion or negatively charged colloidal particle containing chromium and arising from the green modification of chromic sulfate. The action would then be similar to that described in the Procter-Wilson theory of vegetable tanning.
In support of their theory, Thompson and Atkin cite a number of investigations showing that anodic migration occurred in the electrophoresis of solutions of the green modification of chromic sulfate. It was pointed out by Seymour-Jones,?? however, that this theory would be acceptable only provided it could be shown that all chrome liquors capable of tanning contain this negatively charged chromium complex.
Bassett ** electrolyzed solutions obtained by the reduction of potassium bichromate with sulfur dioxide. With fresh, dilute solutions, no precipitate was obtained with either barium chloride or ammonium hydroxide, indicating the absence of sulfate or chromic
type Seon: When fresh green solutions, containing a
slight excess of sulfur dioxide, were electrolyzed under dilute sulfuric acid, a green boundary moved to the anode and a violet boundary to the cathode. With lapse of time the anodic migration decreased in speed and finally ceased altogether.
Seymour-Jones points out that the cessation of anodic migration on standing is important to the theory, since it implies the breaking up of the negative complex to potassium sulfate, potassium sulfite, and chromic sulfate, ‘and, consequently, the absence of chromium in a negative complex in ordinary chrome liquors. Moreover, if the green solution is due to chromic anion and the violet to chromic cation, pure violet solutions should not tan, according to the ThompsonAtkin theory, but Burton 24 found that the violet modification tans more rapidly than the green. This seemed a natural finding in view of the fact that Blockey 2° had previously shown that the hydrogen-ion concentration of solutions of the green modification is very much higher than that of solutions of the violet modification.
Ricevuto 2* electrolyzed a 10-per cent solution of chrome alum and observed migration only to the cathode. Upon addition of sodium hydroxide, the solution became turbid and some particles moved to the anode. When the solution was rendered alkaline, the particles moved entirely to the anode, from which Ricevuto concluded that chrome tanning is possible only in alkaline solution, which we know . to be quite contrary to fact.
Seymour-Jones carried out a number of electrophoresis experiments on various chromic solutions for the purpose of testing the Thompson-Atkin theory. A U-tube was used which was provided with a stopcock in each arm a little above the bend. The chromic solution was placed in the bend below and up to the top of the stopcock. Above this was placed a 0.05-molar solution of sodium sulfate. The U-tube was connected by stoppers with electrodes in small distilling flasks, copper in saturated copper sulfate serving as the cathode and platinum in saturated sodium chloride solution as the anode. Diffusion of these solutions was prevented by cotton wool plugs. The ordinary house current of 110 volts D. C. was used, passing through © a lamp filament to reduce the amperage to a convenient amount. The results are given in Table XX XVII.
Wherever chrome liquor moved to the anode, it was of a pure green color, while that moving to the cathode was of a bluish green. The basic chromic chloride, which showed no anodic migration at all, was used to tan hide powder, which it did in quite the normal manner. This proves that the Thompson-Atkin theory is not of general application and suggests that it may not hold in any case.
25 Investigation of One Bath Chrome Liquors. J. R. Blockey. J. Soc. Leather Trades Chem, 2 (1918), 205. — : = , 2 1g SN od Bes Rai) 88 Kolloid Z. 3 (1908), 114.
Seymour-Jones 77 experimented upon the ultrafiltration of basic chromic sulfate, such as is used in tanning, and found no colloidal matter. A chrome liquor was prepared by reduction of a solution of sodium bichromate with sulfur dioxide, the excess sulfur dioxide being driven off by boiling. The dark green solution contained 269.9 grams of chromic oxide per liter. This was ultrafiltered through hard filter papers impregnated with 1-per cent and 5-per cent gelatin solutions, respectively, which were subsequently hardened with 4-per cent formaldehyde solution. The solution was also ultrafiltered through a
collodion disc. In every case the solution passed through unchanged, no colloidal particles being retained by the filter. The same result was obtained when the solution, diluted with 3 volumes of water, was allowed to remain in a collodion bag suspended in air. The original, concentrated solution and one diluted to 10 volumes with water were dialyzed in collodion bags against water, which was changed frequently. In less than 18 hours even the concentrated solution had completely dialyzed through the membrane, the liquid remaining in the bag being colorless. This shows that we are not dealing with a colloidal dispersion in chrome tanning.
T. W. Richards and F. Bonnet 7° electrolyzed a basic chromic sulfate solution and found the migration entirely cathodic and there were 19.3 grams of Cr transported per 96,580 coulombs. From this they concluded that each atom of chromium cannot be associated with more
than two positive charges and probably with not more than one. Assuming that the sulfate ion alone migrates anodically with a mobility of 70, the mobility of the chromium group is 41 assuming a single charge and 243 assuming a double charge, but the latter figure appears much too high. They suggest that the cation may be Cr(OH).*, which Siewert *° and Whitney *° had shown to be the most pees cation in boiled solutions of chromic chloride or nitrate.
The author’s view of the mechanism of chrome tanning is as follows: Although the degree of ionization of the carboxyl groups of the protein, in which a hydrogen ion passes into solution, may become extremely small with increasing acidity, it never becomes zero. This means that, even if the electrical charge on the protein structure is predominantly positive, there still remain a relatively small number of negatively charged groups scattered throughout this structure. Cr(OH).*, or ions of a similar nature, diffuses into the jelly composing the fibers of the skin and combines with these negatively charged groups wherever encountered. Having neutralized the electrical charges on each other, both the collagen and chromium groups become capable of ionizing further, the chromium group giving off another hydroxide group and the collagen a hydrogen ion. With a repetition of this process, all three bonds of the chromium become united directly with the collagen structure. The fundamental assumption underlying this view is that however small may be the concentration of negatively charged groups in the collagen structure under the conditions of tanning, it is very much larger than would result from the dissociation of the chromium compound of collagen.
This theory is not antagonistic to the Procter-Wilson theory of vegetable tanning, but actually supplements it. In vegetable tanning, the tannin probably attaches itself to the amino or other basic groups of the protein structure; in chrome tanning, the chromium attaches itself to the carboxyl or other acid groups. This is corroborated by the fact that chrome tanning apparently does not lessen the capacity of the skin for combination with vegetable tanning materials, or vice versa. Wood *! found that plates of gelatin tanned with chromium were capable of combining with as much tannin as before the chrome tanning, suggesting that the chromium and tannin are not attached to the same groups in the protein structure. This is not in accord with the Thompson-Atkin theory, in which both chromium and tannin would be attached only to the positively charged groups of the protein. That the collagen undergoes a chemical change in chrome tanning is proved by the fact that it loses its property of being convertible into gelatin by contact with boiling water.
Of the innumerable substances capable of combining with. collagen, the only ones classed as tanning agents are those whose compounds with collagen are but little dissociated, imputrescible, incapable of swelling greatly in water, and stable under ordinary condition and which cause the skin fibers to lose their tendency to glue together during drying. The suitability of a material as a tanning agent naturally depends upon its availability and cost, the simplicity of its use, and the properties of the leather which it yields. The high quality and yield of leather given by the natural vegetable tanning materials and the simplicity of tanning with chromium compounds make these two classes of materials the favorites in leather manufacture. Other materials, however, find a place in the manufacture of special types of leather, either alone or in conjunction with vegetable or chrome tanning materials.
Attempts to combine the advantages of both chrome and vegetable tanning have met with some success for certain classes of leather. During the war there was a demand for vegetable tanned leather for shoe uppers, but the length of time required for the tanning of hides to produce this leather made it impossible to meet the demand. The tanning could be done quickly enough with chrome liquors, but the resulting leather was not suitable. It was found, however, that the leather could be made to serve the purpose tolerably well by giving it a partial tannage in vegetable tan liquors after it had been completely tanned with chrome. The best example of this was the so-called chrome retan army upper leather, a vertical section of which is shown in Fig. 148. This leather was made from cow hide and was first tanned with chrome liquor and then hung in vegetable tan liquor for a few days, or until the tan liquor had penetrated more than half of the thickness of the hide. The hide was then split down to the required thickness, although the splitting was done before the retanning in some cases. The lightly colored band running across the lower half of the picture represents the inner layer of the hide to which the tan liquor did not penetrate. It appears nearer to the flesh surface only because the hide was split after retanning. It will be noted that the fibers in the retanned portions are larger than those in the pure chrome layer. At the lower left hand corner, a fiber can be
Eyepiece: none.
Thickness of section: 40 p. Objective: 16-mm. “Stain: none. Wratten filter: K3-yellow. “'Tarinage: chrome plus vegetable. Magnification: 54 diameters,
decreases noticeably.
The advantage of the preliminary chrome tanning lies in the speed with which the subsequent vegetable tanning operation may be carried out. The chrome tanned hides may be put at once into liquors stronger than usual, which hastens the rate of penetration, and it is not necessary to wait for complete diffusion, since the chrome tanning of the middle layer renders it imputrescible. ‘The vegetable retanning adds firmness to the leather and also reduces the sulfuric acid content of the chrome leather to about half its normal value. i
Alum Tanning.
The use of aluminum salts for tanning skins dates back to. very early times and is still applied to some kinds of leathers and in the manufacture of some furs. It never gained the popularity accorded to chrome tanning, however, because the initial compounds formed between collagen and aluminum compounds are much less stable than the ones formed with chromium compounds. Assuming that aluminum hydroxide is a stronger acid than chromium hydroxide, our theory of chrome tanning offers a plausible explanation of this fact. It would then be more difficult for all three bonds of the aluminum to combine with collagen. Where only two bonds of the aluminum are combined with collagen, we should expect the resulting compound to be very much more readily hydrolyzed than where all three bonds are combined. After drying and storing for months, alum leathers become much more stable and resistant to washing, suggesting that the combination of the third bond of the aluminum with collagen requires a long time.
Some support is given to this view by the work of Lumiere and Seyewetz! and of A. and L. Lumiére* on gelatin. They studied the combination of both chromium and aluminum salts with gelatin and found maximum limiting values for the extent of combination of metal with protein, under the conditions of their experiments. They found that 100 grams of gelatin combine with a maximum of 3.6 grams of Al,O, or 3.2 to 3.5 grams of Cr.O;. Taking 768 as the equivalent weight of gelatin and assuming that it combines with all three bonds of the chromium or aluminum, we calculate that 100 grams of gelatin would combine with 3.30 grams of Cr.O3 or 2.21 grams of AI,Os. The-agreement in the case of the chromic oxide is good, but the observed amount of combined alumina is about fifty per cent greater than that calculated, which, however, would be expected if only two bonds of the aluminum combined with the gelatin.
In any case alum tanning must be conducted very differently from chrome tanning. Chrome leather is resistant to washing immediately after tanning, but if freshly tanned alum leathers are washed, aluminum salts are given up and the skins swell as in dilute acid.
1 Composition of Gelatin Rendered Insoluble by Salts of Cl i ioxi Lumiére and A. Seyewetz. Bull. soc. chim, 29 (1903), 1077. Bara atm eed oe 2 Action of Alums and Aluminum Salts on Gelatin. A. and L. Lumiére. Brit, J. Phot. 53 (1906), 573. .
OTHER METHODS OF TANNING 313
In practice the skins are tumbled in a solution of basic aluminum sulfate and enough sodium chloride to prevent undue swelling of the skin. It is sometimes desirable to add enough sodium bicarbonate to the liquor, after the alum has completely penetrated the skins, to bring it to the point at which precipitation just begins. After a few hours longer, or next day, the skins are rubbed with a mixture of egg yolk, cottonseed oil, and flour, but are not washed. They are then allowed to dry thoroughly. Sometimes the egg yolk mixture is added to the tanning bath. The skins are kept in the dried state for weeks, or months, to give the aluminum time to become permanently fixed. The skins are then soaked in water to remove the salt and are fatliquored and colored and finished according to the kind of leather required.
In tanning skins for furs, it is customary to work the alum solution into the skin from the flesh side, supplemented with oils to keep the skin soft. Work of this kind is usually done by hand and requires some skill in order to get the best results. Fig, 149 shows a section of alum tanned fur, known as Persian lamb. Skins for this fur are from specially bred lamb slinks. In this particular skin, the wool and skin were dyed black with logwood and iron salts.
The tanning properties of ferric salts have been known for more than a century, but attempts to manufacture iron tanned leathers have met with so many difficulties that the subject still remains in the experimental stage at this late date. Procter*® points out that part of the trouble is due to the fact that iron salts are oxygen carriers. Ferric salts readily give up oxygen to certain kinds of organic matter, being reduced to the ferrous state, in which they take up oxygen from the air, under suitable conditions, returning to the ferric state. In this way a slow oxidation of the leather occurs, with consequent deterioration. )
Jettmar* found the greatest difficulty in iron tanning to be that of proper neutralization of the leather. If chrome leather contains too high a proportion of sulfuric acid, it becomes very brittle upon drying and assumes a.very dark green color. But the proper degree of neutralization of chrome leather is a comparatively simple matter. In attempting to neutralize iron tanned leather, Jettmar found that the iron salts became colloidally dispersed and were washed out of the leather. Apparently the neutralization is necessary to bring about a permanent combination between iron and collagen, but the iron compounds pass into the colloidal state, upon neutralization, before they have had the opportunity to combine with the collagen. Since colloidal ferric oxide carries an electrical charge of the same sign as that on the collagen in acid solution, there would be no tendency for
the two to combine. This difficulty was partly overcome by using a strong solution of neutral salt to prevent the formation of colloidal ferric oxide during the neutralization. The iron tanned leather was improved in quality by retanning it with formaldehyde.
Rohm * patented the use of the salt FeSO,Cl for tanning. It is obtained by the action of chlorine upon ferrous sulfate. Just why this salt should have unusual tanning properties is not made clear.
A good summary of much of the work done on iron tanning is contained in a paper by Jackson and Hou,°® who carried on an extensive investigation of the tanning properties of iron salts. They pointed out that investigators generally seem to have the idea that the salt responsible for the tanning action has the formula FeOHSOs,, whereas this salt is not stable in solution, but invariably gives a precipitate of hydrated ferric oxide. They attribute the brittleness usually associated with iron tanned leathers to improper tanning, resulting from the precipitation of this hydrated ferric oxide. They showed that ferric sulfate is much more readily precipitable than chromic sulfate by diluting a solution of the two. With increasing dilution, there was a progressive precipitation of iron, but the chromium remained in solution.
Jackson and Hou prepared iron tanned leather which they were convinced compared favorably with other mineral tanned leathers. Its character seemed to lie between that of alum and chrome leathers. It would not stand the action of boiling water, but would shrink when brought into contact with water having a temperature above 75° C. They summarize the chief factors in their findings as follows: The iron salts must be kept in the ferric state by using an excess of a - proper oxidizing agent and by means of an after oxidation. During tanning, the acidity of the liquor must be so adjusted as to give a basic salt of iron in which the ratio of equivalents of hydroxide groups to equivalents of acid radical is never less than 1:5 nor more than 1:3. Neutralization must be effected so gradually as to effect a uniform fixation of iron throughout the skin. The leather must be dried before subsequent treatment in order to minimize the reactions between free iron and materials used later that would give the leather an undesirable color.
During the war the scarcity of tanning materials forced Germany to investigate every available source, including iron salts, and had the war continued long enough, she might have been forced to produce iron tanned leathers on a large scale. But, unless iron leathers are produced which are at least the equal of chrome leather, it is doubtful that they will ever be made on an extensive scale, except in cases of emergency, because the total cost of tanning material used in making chrome leather is small compared to the loss in selling price that would result from even a very small depreciation in quality of the leather. 7 :
Tanning with Silicic Acid.
Like tannin, colloidal silicic acid’ is negatively charged and precipitates gelatin from solution. In 1862 Thomas Graham’ studied the precipitation of gelatin by silicic acid and reported as follows: “Silicate of gelatine falls as a flaky, white and opaque substance, when the solution of silicic acid is added gradually to a solution of gelatine in excess, The precipitate is insoluble in water and is not decomposed by washing. Silicate of gelatine, prepared in the manner described, contains 100 silicic acid to about 92 gelatine. In the humid state the gelatine of this compound does not putrefy. When a solution of gelatine was poured into silicic acid in excess, the co-silicate of gelatine formed gave, upon analysis, 100 silicic acid with 56 gelatine.”
This experiment inspired Hough ® to experiment with silicic acid as a tanning agent. He found that a purified silica sol is much too easily precipitated to be of any value as a tanning agent, but finally prepared a solution of silicic acid capable of tanning by adding a thirtyper cent solution of sodium silicate to a thirty-per cent solution of hydrochloric acid until the concentration of free acid was reduced to decinormal. If the acid is poured into the sodium silicate solution, the silica will be precipitated when the neutral point is approached ; the silicate must always be poured into the acid solution whose strength must not be allowed to fall below decinormal. The tanning proceeds a little faster than is the case with vegetable tanning, light skins being fully tanned in from 3 to 5 days, and heavy bull hides in about a month. ‘The leather usually contains from 17 to 24 per cent of silica; in fact one of the difficulties of the process is to prevent too great a combination of silica with the skin protein. The leather is pure white and may be finished like ordinary chrome leathers.
Hough attributes the failure met with in attempting to combine silica and vegetable tanning to the fact that both the silica and tannin are negatively charged and tend to combine with the same amino groups of the collagen structure. On the other hand, good leathers were produced by a combined silica and alum tannage, probably because the alum attaches itself to the carboxyl groups of the collagen. The presence of alum, however, seemed to retard the tanning, pos sibly on account of the condensation of aluminum silicate on the surface of the skins hindering the penetration. But by giving the skins a preliminary chrome tannage and then putting them into the silica liquors, the raté of tanning was increased and the final leather had greater solidity and firmness. :
In discussing the evolution of the different methods of tanning, Thuau ® states that one serious fault with silica tanning is that the leather, after keeping for a few months, tears very easily, probably because of the action of the silicic acid on the leather fibers. If
Miscellaneous Mineral Tannages.
Sommerhoff ?° claims to have discovered that certain insoluble sulfides, silicates, hydroxides, and phosphates of the heavy metals have a marked tanning effect on skin, when freshly precipitated or colloidally dispersed. In one experiment, copper sulfate was precipitated with disodium phosphate. “he jelly-like precipitate was filtered off and then suspended in water and shaken with a piece of hide, which became completely tanned in about two hours. ‘The leather contained about 13 per cent of ash. Whether Sommerhoff really obtained a
seems not to have been carried very far.
Garelli ++ found that the tanning properties of cerium chloride are much like those of aluminum salts, provided the solution used for tanning 1s made sutficiently basic and dilute. Wiauth properly adjusted conditions, he obtained a pliable, white leather containing about 9g per cent of Ce,03. Garelli and Apostolo’* were not so successful in attempting to tan skin with salts of bismuth. lf any compound between the bismuth and collagen were formed, it was unstable, the skin returning to the raw condition upon washing in cold water.
‘he experiments of Apostolo ‘* seem to indicate that freshly precipitated suitur has tanning properties. He added a small amount of lactic acid to a concentrated solution of sodium thiosulfate, which became turbid, due to the precipitation of sultur. Into the turbid solution he put a piece of skin, which apparently absorbed all of the free suitur. ihe skin was withdrawn long enough to add a little more acid to berate more sultur. ‘Lhe skin was returned to the liquor and it again absorbed all ot the sultur in suspension. ‘his was repeated a llumver ot times, care being taken to avoid using acid in excess of the amount of sodium thiosuitate present. ‘he leather obtained is described as white, extraordinarily soft, and of beautiful appearance. it did not swell when lett for 24 hours in cold water, and when dried and stretched again had lost none of its quality. ‘The leather gave up only I per cent of sulfur to carbon disulfide and this seemed to have been merely mechanically held, as the remaining skin seemed still to be fully tanned, and contained 2.5 to 3.5 per cent of sulfur. . The leather was decomposed, however, when brought into contact with hot water.
rendered insoluble by contact with aqueous solutions of either bromine or chlorine, in the presence of salt to prevent swelling. The gelatin evidently combines vigorously with either element. Raw skin was found to be affected similarly. Iodine had no such effect on either gelatin or skin. The authors suggested the use of chlorine or bromine as a preservative for skin and also as a tanning agent to be used prior to tanning by other methods for all kinds of skins. The leather obtained is absolutely imputrescible and resistant to cold, but not boiling, water.
One of the commonest examples of oil tanned leather is the ordinary chamois leather. This is made from the reticular layer of sheep skin, which is split from the grain layer so that the two may be tanned separately for very different purposes. The flesh splits are soaked with cod oil and pummeled in specially designed machines in order to assist the penetration of the oil. A combination of oil with the skin protein takes place with the evolution of acrylic aldehyde and other pungent products and the development of a considerable amount of heat. Oxidation of the oil occurs simultaneously. The pummeling, or stocking, is stopped occasionally and the skins are spread out to cool off, after which the stocking is continued. The completion of the process can only be determined by practice. After tanning, the splits are soaked for a few hours in warm water and then pressed to remove uncombined oil, which is sold under the name moellon degras. The oil still adhering to the skins is removed by washing with a solution of sodium carbonate. The skins are then bleached in strong sunlight.
The nature of the combination of oils with collagen has been studied by Fahrion*® and by Meunier.*® According to Fahrion, the unsaturated, free fatty acids are the active tanning agents of the fish oils in chamoising. The active acids have at least two double bonds and upon oxidation they assume a peroxide structure represented by the formula
Representing collagen by the simplified formula R’NHz, the combination of oxidized fatty acid and collagen, according to Fahrion’s view, would yield the following compound:
genni G OH
These hydroxy-acids are then converted into lactones which are retained by the fibers, being resistant to the alkaline washing which completes the manufacture of chamois leather.. The aldehydes formed in the process probably also exert a tanning action on the skins.
According to Meunier, the tanning power of fish oils is due to the presence of free fatty acids possessing four double bonds of which at least two are capable of combining with oxygen to give the peroxide structure shown above. Thus if a skin, previously dehydrated with alcohol, be treated with an alcoholic solution of oleic acid, a soft leather is obtained, but after draining off the alcohol to remove the excess of oleic acid, the skin does not show any sign of being tanned when placed in water. Substituting the fatty acids of rape oil for oleic, a yellow leather somewhat more resistant to the action of water is obtained. These acids belong chiefly to a series possessing two double bonds and include a little linolenic acid, with three double bonds. Substituting the fatty acids of linseed oil, rich in linolenic acid, the leather obtained is still more resistant to water, but is not the equal of that made from the fatty acids of cod oil possessing four double bonds.
Tanning with Aldehydes and Quinones.
Payne and Pullman‘ patented the use of formaldehyde as a tanning agent in 1898. Since then a number of investigators have studied the action of various aldehydes upon gelatin and skin protein. Some aldehydes, like benzaldehyde, show little or no tanning power. The use of formaldehyde has frequently been suggested as a means of preparing skins for tanning with vegetable tanning materials by the newer rapid methods, in which stronger tan liquors are used. The formaldehyde adds very little weight to the leather, but its combina-
Hey 1® observed that formaldehyde has tanning properties only in solutions having a pH value greater than 4.8 and that the best practical results are obtained when the pH value lies between 5.5 and 10.0. At higher pH values the skin becomes swollen and the surface be-. comes almost impermeable to the formaldehyde not combined with the skin at the surface. Meunier suggests that oxidation of the skin proteins, affecting the amino groups, precedes combination with either aldehydes or quinones, whose tanning properties were discussed in Chapter 13. When quinone combines with skin protein, part of the uncombined quinone is reduced to quinol, which Meunier attributes to the oxidation of protein.
Meunier also studied the action of gallic acid, naphthols, quinol, pyrogallol, diaminophenol hydrochloride, and resorcinol upon gelatin. When these substances are dissolved in dilute solutions of sodium carbonate and exposed to air, they act slowly upon gelatin, rendering it insoluble in boiling water. Without access to the air, however, this action is not obtained.
Tanning with Syntans.
In vegetable tanning, in slightly acid solution, combination takes place between positively charged protein and negatively charged colloidal particles of tannin. A distinct advance in the science of tanning was made when Stiasny *® discovered that water soluble products can be obtained by mixing phenolsulfonic acids with formaldehyde, under the right conditions, in which the particles formed are negatively charged in acid solution, precipitate gelatin dispersions, and possess marked tanning properties. Equal parts of cresol and sulfuric acid are heated, with stirring, for two hours, the temperature being kept at about Io a Oe The mixture is then cooled to 35° C. and 1 molecule of formaldehyde is added for each molecule of cresol present. The important point to be observed is that the formaldehyde must be added very slowly and the temperature must not be allowed to rise above 35° or the ordinary insoluble products may be obtained.
Resides cresols, naphthalenes and higher hydrocarbons are also used in the preparation of these synthetic materials, now commonly called 18 Formaldehyde Tannage. A. M. Hey. J. Soc. Leather Trades Chem. 6 (1922), 131.
Raw skin can be tanned by simply immersing in a pure solution of these syntans, provided the concentration and acidity are properly adjusted. With, decreasing acidity, they seem to lose their tanning properties. A typical commercial syntan preparation examined by the author showed a titrable acidity of 0.65 gram equivalents per liter and a pH value of 0.63. Grasser found that concentrated solutions of Neradol D, the original syntan, actually cause a gelatinization of raw skin, which might have been expected from its high acidity. But when used at sufficient dilution, no ill effects were observed at all and a tough, white leather was obtained. Since syntans add much less weight to skin than natural vegetable tanning materials, they are seldom used: alone, but appear to have valuable properties when used in conjunction with other materials for certain kinds of leather. |
Like formaldehyde and quinone, syntans act upon skin in such a way as to lessen the astringent effects of strong tan liquors upon it. Syntans, having a lower molecular weight than tannins, diffuse into the skin at a much greater rate and also combine with it. This partial — tannage lessens the rate of combination of the tannin with the skin, thereby increasing its rate of diffusion. The syntan solution may be used as a drench for deliming the skins prior to vegetable tanning or may be added directly to the tan liquors. Like any strongly acid material, however, it must be used with caution and proper control.
The high acidity of ordinary syntan solutions makes them suitable ‘for the bleaching of leather, the color of the leather becoming lighter with increasing acidity, or decreasing pH value, within limits.
Another valuable property of these syntans is their power to effect the solution of phlobaphenes and other difficultly soluble tannins. Grasser found that the phlobaphenes of quebracho were rendered soluble by solutions of Neradol D or sodium phenolsulfonate, but not by the free sulfonic acid. The action of the sodium salt, however, may be attributed at least partly to the pH value of its solution, since the author found phlobaphenes to be very soluble at pH values above 7. Since the phlobaphenes are probably oxidized tannins, it is possible that the syntans exert a reducing action upon them, but the real nature of the action is not known.
The method of determining the extent of penetration of Neradol D in tanning is to wash a strip of the skin, make a cutting, wash the cut portion, and then treat it with a few drops of dilute ferrous ammonium sulfate solution, which color the tanned layers a deep blue.
Another material that should be mentioned in connection with syntans is the waste sulfite liquor from the paper mills, known as sulfite cellulose. This material, purified for tanning purposes, is sold under the name of spruce extract. The active tanning agent of this material appears to be the free lignosulfonic acids. Spruce extract possesses undoubted tanning properties, but does not yield a satisfactory leather when used alone in the ordinary way. But when mixed
with other materials, such as quebracho extract, it acts much like many natural vegetable tanning materials. Its very low costs finds it a place as a filler in the manufacture of sole leather. Hill and Merryman 2! describe a method of increasing the filling properties of spruce by the use of syntans. Sole leather is first soaked in a concentrated solution of spruce and then drummed with a solution of syntan. They claim that the spruce is precipitated inside of the leather _ by the syntan, greatly increasing the weight and at the same time brightening the color and lessening the need for bleaching.
Finishing and Miscellaneous Operations.
The mere conversion of raw skin into leather does not, as a rule, make it suitable for the various purposes for which leather is used. For some kinds of leather, more work is required in the operations following the actual tannage than in the tanning and all preceding operations put together. Each of the innumerable kinds of finished leather requires a special series of operations after tanning and nothing short of an encyclopedic work could adequately treat the details of operations, even for the commoner leathers. For this reason, the following brief treatment is limited to the fundamental principles underlying the few general processes common to large classes of leathers.
In vegetable tanning there is often a deposit of phlobaphenes or of ellagic acid on the surfaces of the leather which, if left there, would ~ interfere with the coloring of the leather, giving rise to irregularities. It also frequently happens that the color of the leather becomes dark through oxidation and this may not be entirely uniform over the surface of the leather. Bleaching is a process designed to give the leather a lighter and more uniform color before it is sent to be dyed and fatliquored. It usually consists in giving the leather a bath first in a dilute alkaline solution and then in an acid one, sodium carbonate and sulfuric acid generally being used for the purpose. .
When the leather is soaked in dilute sodium carbonate solution, the phlobaphenes and ellagic acid pass into solution, being soluble at pH values greater than 7. At the same time the tannins are stripped from the surfaces of the leather; it was shown in Chapter 13 that this stripping action proceeds at an increasing rate as the pH value is increased above 8. The sodium carbonate solution is usually allowed to act for only Io or I5 minutes and the leather is then rinsed to free it from the soluble products on the surface. It is then treated with a dilute solution of sulfuric acid, which checks the action of the sodium carbonate and at the same time lightens the color of the remaining fixed tannins by lowering the pH value, the color being a function of pH value, as pointed out in Chapter 11. In this way the grain surface is cleared and the color brightened. After the bleaching, it is customary to replace the tannin lost from the surface by giving the leather a short tannage in clear tan liquor.
The use of sulfuric acid in bleaching leather has been condemned on the ground that it slowly destroys the leather, if not subsequently removed. When sulfuric acid is present in vegetable tanned leather in excess of I per cent of the weight of the leather, the leather may look all right for two or three years, but gradually deteriorates and in time will become as tender as blotting paper. The tanner usually takes care that the amount of acid used is not excessive or counteracts it by using an alkaline fatliquor, which neutralizes any acid left in the leather. Other bleaching agents sometimes employed are sodium bisulfite, organic acids, and syntans.
Stuffing and Fatliquoring.
Although the tanning of skin lessens the tendency for the fibers to glue together upon drying, it does not lubricate them so that they slip easily over one another. In fact, when leather is dried after tanning, without further treatment, it is usually very stiff and will crack upon bending sharply. In order to give it the desirable softness and pliability and to increase its tensile strength and resistance to tearing, oils and greases are incorporated into it to lubricate the fibers.
The amount of oil added to leather varies greatly according to the use to which the leather is to be put. In sole leather, where stiffness is desired, only 2 or 3 per cent of sulfonated oil is used and this is often added along with the concentrated tan liquor or other material used to fill and weight the leather. Waxed leathers, used for waterproof shoes, may contain as high as 30 per cent of oils, waxes, and stearin.
The direct application of oils and greases to leather, either by hand or by drumming in the molten greases, is known as stuffing and is used where it is desired to incorporate a large amount of grease into the leather. Where only a small amount of oil is desired in the leather and it is essential to have it fairly uniformly distributed, it is best to apply the oil in the form of an emulsion, in which case the process is known as fatliquoring.
In dry stuffing, the dried leather is treated with hot, molten greases, which penetrate rapidly. This method is suitable only where it is desired to have a finished leather containing upwards of 20 per cent of grease. For leathers with less grease, it is preferable to apply the greases to the wet leather. In belting leather, for example, it is customary to swab a mixture of cod oil and tallow over the surfaces of the leather while thoroughly wet. The leather 1s then hung in a drying chamber in which the temperature is gradually raised. As the water passes out of the leather, the oil and tallow diffuse in. When a small amount of oil is rubbed onto dry leather, the surface tends to remain oily, but when applied to wet leather, the surface of the leather after drying is not oily. For this reason it has been assumed that the evaporation of water from the leather draws the oil into the leather, but this view has been contested by
Moeller? who considers the action of oils upon wet leather as similar to that of cod oil in chamoising. According to his view, the vegetable tanning material causes an oxidation of the unsaturated fatty acids, as indicated by the formation of oxidized acids and the simultaneous disappearance of water from the leather, water presumably being essential to the reaction. The oxidized fatty acids then act as a tanning agent. When dry leather is oiled, this action proceeds so slowly that the leather always remains oily, whereas wet leather, after oiling, dries without retaining the oily condition.
The effect of grease in increasing the tensile strength of leather was demonstrated in a special investigation by Whitmore, Hart, and Beck,? who found that a petrolatum-paraffin mixture was quite as effective as the commoner cod: oil-tallow mixture. Bowker and Churchill ? showed that grease in excess of a certain amount does not add to the tensile strength, but may actually decrease it. This agrees with some observations made by the author in the stuffing of strap leather, in which the tearing strength decreased with increase of grease content above 21 per cent.
Light leathers, such as those for shoe uppers, are fatliquored rather than stuffed because fatliquoring leaves the grain surface in a much better condition for coloring. The common emulsifying agents are sulfonated oils, soaps, and moellon degras, the by-product from the manufacture of chamois leather. For a review on the literature of emulsions, the reader is referred to the paper by Thomas.t In the manufacture of chrome leathers, it is sometimes necessary to neutralize a portion of the sulfuric acid of the leather before applying the fatliquor, which is done by drumming the leather in a calculated quantity of sodium bicarbonate or borax solution. A fatliquor may be made simply by shaking a mixture of sulfonated neatsfoot oil, neutral neatsfoot oil, and hot water. Or the sulfonated oil can be replaced by soap and moellon degras. Van Tassel *® proposed the use of stearamid as an excellent emulsifying agent in making fatliquors. Larger quantities of fatliquor are used for vegetable tanned leathers than for chrome. A finished chromé leather generally contains from 4 to 8 per cent of oil against from 10 to 15 per cent for vegetable tanned upper leathers. )
The skins are thoroughly wet with hot water and drummed with a small volume of hot fatliquor for. about half an hour, at the end of which time practically all of the oil should be separated from the solution. It has often been thought that the oil globules actually penetrate the leather during fatliquoring, but Albert F. Gallun {renin
Wl aS of Ola: Crecien aa Beaten Ge Penne, Cheat ae Harness Leather. R. C. Bowker and J. B. Churchill. A. W. Thomas. J. Ind fs, : ay Nes Emulsifying Agent and Its Pee i ee 3 : were Jr. J. Am, Leather Chem. Assoc. 9 (1914), 236. y Practice. E. D, Van Tassel,
an unpublished work, showed that they do not do so. By splitting skins into layers immediately after fatliquoring, he found by analysis of each layer that the oil had not penetrated a measurable distance. Upon drying, however, the oil slowly diffuses into the interior and tends, in time, to distribute itself uniformly throughout the skin. The author split a skin into five layers after it had been dried after fatliquoring and found the highest percentages of oil in the outermost layers and the lowest in the layer just under the grain surface. This is probably due to the fact that the fibers of the flesh side of the skin offer more surface to the oil globules than the grain surface and hence the greater portion of the oil adheres to the flesh side.
The discussion of the stability of colloidal dispersions given in Chapter 5 may be applied to fatliquoring. The oil globules possess a negative electrical charge which gives the surface film of solution surrounding each globule an electrical difference of potential against the bulk of solution. The condition of leather to be fatliquored may be taken as that of leather in equilibrium with a solution having a pH value of from 4 to 5. The leather thus carries a positive electrical charge. The effect of putting such leather into a fatliquor, although similar in some respects to the immersion of skin in a vegetable tan liquor, is very different in at least two ways: the oil globules are very much larger than tannin particles and are not stable at pH values much below 6. The negatively charged globules will tend to combine with the positively charged leather and there may actually be some combination. But the emulsion is quickly broken up by the soluble matter present in the leather. The stability of the emulsion may be increased by making it more strongly alkaline, but this must be done with extreme caution or the leather will be ruined by overneutralization.
Experience shows that the more quickly the emulsion is broken up during fatliquoring, the greater the difficulty of setting a uniform distribution of the oil throughout the leather upon drying. For this reason the water soluble matter contained in leather to be fatliquored may exert a detrimental effect. The soluble tanning matters remaining in the leather have a tendency to break up the emulsion and, if present in too great an amount, may break the emulsion before the fatliquor has had time to serve its purpose properly and the leather will dry hard and crack easily. On the other hand, a leather practically free from soluble matter takes the fatliquor so well that it may become too soft after drying unless a smaller amount of oil is used in fatliquoring than is applied to leathers containing much soluble matter.
Penetration of Dispersions through Grain Surface.
It is interesting to note how small the particles of a dispersion would have to be in order to pass between the fibers constituting the erain surface of the leather, without distortion and assuming they could pass without coalescing or combining with the leather. Fig. 150 shows a horizontal section of vegetable tanned calf skin comprising the grain surface. The view is that looking down on the uppermost sur-
face which has been cut away from the leather below it at a thickness of less than 15 microns. (The exact measurement of thickness could not be made because this was the first cutting of the paraffin block at 15 microns that included any leather at all and was taken so as not to lose the upper surface.) The section was stained for 2 minutes in a I-per cent solution of indigo carmine, The specimen was taken from a skin about to be fatliquored.
The average distance between the fibers of the surface is about 2 microns. If size of particle alone counted, it would merely be necessary to prepare the dispersion so as to get particles having a diameter less than this. The large empty spaces in the figure are the openings of the empty hair follicles. In the ordinary course of fatliquoring, these probably become filled with oil as soon as the emulsion breaks.
Fatty Acid Spews.
‘This deposit, known to the trade as spew, usually consists of saturated fatty acids having a high melting point. For this reason, many tanners try to avoid the use of oils containing much stearin or free stearic or palmitic acids. Where sulfonated oils have been used, the deposit may contain sulfonated fatty:acids, which are more difficult to remove from the surface of the leather than pure stearic or palmitic acid. Although the spew does no harm to the leather, it ig undesirable because it detracts from its appearance. Its removal, however, is a comparatively simple matter and may be effected by wiping the surface with a cloth wet with naphtha or with a soap solution.
Fahrion® found that the splitting of a fat, with the liberation of saturated fatty acids, is not the only cause of spew of this kind. Glycerides may appear on the surface of leather which have a lower melting point than those left in the leather. But when the fatty acids are liberated from the spew, they are found to have a higher melting point and a greater tendency to crystallize than the fatty acids liberated from the glycerides remaining in the leather. A glyceride mixture is likely to cause spewing if another mixture can be separated from it by fractionation which has a lower melting point, but a higher content of saturated fatty acids. He points out that the less the tendency of a fat to crystallize, the more suitable it is for purposes of fatliquoring.
When fatliquors containing saturated fatty acids are used, the danger of spewing can be greatly lessened by incorporating in the fatliquor materials like mineral oils or sulfonated castor oil. These remain liquid at ordinary temperatures and are solvents for the fatty acids and glycerides which form ordinary spews.
When a piece of finished leather spews, it is often noted that the greatest deposits of fatty acids occur where the leather is thinnest. This is due simply to the fact that leathers fatliquored in the ordinary way have a higher total fat content in the thin parts than in the heavier
regions. In fact the fat content of the various parts may be taken as inversely proportional to the thickness. This is easily explained by the fact that the oil globules are deposited only on the surfaces of the leather during fatliquoring. Equal areas of leather thus receive the same amount of oil. If the butt is twice as thick as the shanks, it will receive only half as much oil per unit volume. For the same reason, if a very thick skin is fatliquored along with a very thin one, the thick one will not get enough oil, while the thin one will get more than its share.
A type of spew less common, but more difficult to remove, than that made up of saturated fatty acids is the resinous spew caused by the oxidation of unsaturated fatty acids in the leather. If a vegetable tanned leather contains much soluble tanning material, the tendency for the free tannin to absorb oxygen from the air increases upon fatliquoring due to the resulting increase in pH value. The oxidized tarinin seems to give up its oxygen readily to the unsaturated fatty acids of cod and similar oils. The higher the pH value of the solution in the leather and the greater its content of free tannin and oxidizable fatty acids, the greater will be the danger of the formation of resinous spews, consisting of oxidized fatty acids.
Most tanners appreciate that it is undesirable to allow a large amount of soluble neutral salts to remain in the finished leather and, since such salts are easily washed out during the process, there is no good reason why they should not be removed before finishing. Nevertheless leathers are occasionally found on the market showing a deposit of salt crystals on the surface, resembling spew. It is, of course, an easy matter to differentiate between such salt deposits and ordinary fatty spews.
When leather is kept in a cool, damp place for a long time, it is apt to be subject to the growth of molds. Sometimes these show the light green color of the common mold penicillium glaucum, but often they appear like a white, powdery deposit, resembling the spew sometimes occurring on leathers fatliquored with sulfonated neatsfoot oil.
Coloring.
Leather is dyed either before or after the fatliquoring process, depending upon the kind of leather produced and the nature of the other operations. Natural dyestuffs are still employed for coloring some kinds of leather, but have been largely supplanted by artificial products. In coloring vegetable tanned leather, basic dyestuffs are usually preferred because they combine readily with tannin and give more intense shades than the acid dyestuffs.
When vegetable tanned leathers are to be colored with basic dyestuffs, they must first be washed so that no free tannin will diffuse into the dye bath, where it would be precipitated by the dye and tend to cause spottiness and discoloration of the leather. The leather is sometimes given a short rinsing in sodium carbonate solution in
order to free the grain surface from precipitated tannin and to strip off any excess of fixed tannin, the object being to get clearer and more uniform coloring. The leather is then drummed in a solution of a salt of titanium or antimony, such as titanium potassium oxalate or antimony potassium tartrate, which serves the double purpose of acting as a mordant and of precipitating any remaining free tannin that might otherwise diffuse into the dye bath. The leather is then given a thorough washing and is then drummed in a solution of the dyestuff. Since basic dyestuffs are precipitated by hard waters, where these must be used, they should first be acidified with acetic acid, which will prevent precipitation.
An objection to the use of acid dyes is the fact that strong acids are necessary to develop the color. The sulfuric acid often used exerts a detrimental effect upon vegetable tanned leathers, if not neutralized after coloring. Where later neutralization is objectionable, it is much better to use formic acid to develop the color since this acid appears to have no harmful effects whatever, if not used in excess. It has often been stated that acid dyes are faster to light than basic ones, but this is not uniformly true for leather.
Chrome leather may be dyed in a manner similar to that of vegetable tanned leather if it is first given a light surface retanning with a vegetable tanning material, such as gambier or sumac. The leather, after tanning and neutralizing, is drummed for a short time in a dilute tan liquor, washed, and then mordanted with a titanium or antimony salt, washed again and finally colored, after which it is fatliquored. Where the fatliquoring may cause a bleeding of the color, the dyeing must follow the fatliquoring.
By the use of acid dyestuffs, chrome leather may be dyed directly, without the necessity for a vegetable retanning. In this case, however, either the fatliquoring must be done before the coloring or else the color must be fixed in some way before fatliquoring. One method of accomplishing this is to divide the coloring operation into two parts, the leather being dyed first with an acid dye and then with a basic dye. Since the two kinds of dyestuffs coprecipitate each other from solution, forming insoluble lakes, they show little tendency to bleed into the fatliquor. .
Direct colors may be used on either chrome or vegetable leathers. Alizarine and developed dyes find a use in the coloring of chrome leather. Sulfide dyes are frequently used where it is necessary to get a color very resistant to washing. For lists of the individual dyes and details of their application to leather, the reader should consult the various practical handbooks on leather dyeing.
The shade of colored leathers may be darkened, or “saddened,” by drumming them in solutions of salts of iron, copper, or other heavy metals. In the production of black leathers, it is common to drum the leather first in a slightly alkaline solution of logwood extract and then in a solution of ferrous sulfate to develop the black. This is often topped by a second dyeing with some artificial black dyestuff.
The chemistry of leather dyeing has not yet overtaken the art, although the process is primarily a chemical one. The effect obtained from a given color bath is a function of pH value, concentration, temperature, etc., but the literature contains no record of investigations of leather dyeing under rigidly controlled conditions of pH value, etc., like those on tanning described in Chapters 11 to 14. One nae infer that similar principles are involved in both tanning and
Finishing.
For descriptions of the numerous mechanical operations and machines used in making leather, including splitting, shaving, slicking, samming, drying, staking, rolling, brushing, boarding, plating, glazing, and embossing, reference should be made to books treating the subject from a more obviously practical viewpoint, like those of Procter,’ Lamb,® and Rogers.®
When the leather has been dried, after coloring, it is subjected to various mechanical operations in order to give it the desired physical properties. Ordinary shoe upper leather is coated with a size or finish in order to make it water repellent and more pleasing to the eye. These finishes usually have as a base an aqueous dispersion of gelatin, casein, blood albumin, egg albumin, gum tragacanth, or Irish moss, and are often mixed with colors or pigments. Another popular finishing material consists of a mineral pigment ground in a solution of shellac and borax in water; this is sprayed onto the grain surface of the leather by means of an atomizer. |
Patent leathers are coated with a varnish made from boiled linseed oil, driers, and pigments. The leather is dried in a hot oven after the varnish has been applied. The surface is then rubbed smooth and a second coat applied, after which it is again dried in the oven. This may be repeated several times to get the desired effect. The surface of the leather is finally exposed to the sun or to ultra-violet rays for several hours.
Suede or ooze calf leathers are made from the skins of slinks, chrome tanned, colored, and finished on the flesh side. The so-called buck leathers are made from chrome tanned cow hide, split to give a sufficiently thin layer, including the grain. The grain is buffed on an emery wheel and then dusted with a dry pigment. The names of many of the commoner leathers indicate the method of finishing rather than the animal furnishing the skin. ee of Leather Manufacture. H. R. Procter. D. Van Nostrand, New York
pH value of acid solutions, 89-90 pH value of chrome liquors, 283 precipitation of chrome liquor by alkali, 284
Ammonium sulfate, effect upon
pH value of acid solutions, 89-90 pH value of chrome liquors, 282 precipitation of chrome liquor by alkali, 284
Amylolytic enzymes, 174, 181, 200 Inthrax, disinfection against, 139-41 Attimony salts in mordanting leather,
pH value of acid solutions, 89-90 pH value of chrome liquors, 283 precipitation of vegetable tan liquor,
Conductivity of gelatin dispersions, 120 Connective tissue, 23, 33, 35, 38-64 Co-operation between university and industry, 12-4
Imbedding specimens of skin, 17 Inactivation of enzymes, 187-91 Interfibrillary cementing substance, 68 Spee of acids and bases (tables), O-
Nervous tissue, 23
Neutral salt effect, 89-93, 146, 281-4 Nitric acid, ionization of, 78, 80 Nucleic acid, isoelectric point of, 108 Nucleus of a cell, 25, 46
Su DIE Iielly EX
Thermostat layer of skin, 31, 39-64 horizontal sections of, 44, 45, 46, 47 vertical sections of, 41, 153, 159, 170,
| 125,995 | common-pile/pre_1929_books_filtered | chemistryofleath00wils | public_library | public_library_1929_dolma-0011.json.gz:2965 | https://archive.org/download/chemistryofleath00wils/chemistryofleath00wils_djvu.txt |
TMjSdC33YrC_6Kmn | Macroeconomics | 50 Trade and Efficiency
What you’ll learn to do: define, calculate, and illustrate consumer, producer, and total surplus
Earlier in this course we introduced the concept of efficiency and pointed out that there are several types. Productive efficiency means producing the most output possible with the available resources. In other words, it means producing without waste. If you recall the production possibilities frontier, operating inside the frontier means the society is not producing efficiently, since all resources are not being used. Productive efficiency occurs only on the PPF.
But there are an infinite number of points on the PPF. What is the optimal point on the PPF, or what is the optimal quantity of each good for society to produce? The answer to this critically important question is given by allocative efficiency. Allocative efficiency maximizes the net social benefit of some product. These same ideas about efficiency can be applied to individual markets. When markets are free and competitive, equilibrium results in the efficient amount of a good or service is produced. By contrast, anytime there is a price ceiling or price floor, or when market participants do not buy and sell at the equilibrium price, the amount of the product being supplied will be inefficient. and society will suffer a deadweight loss.
Learning Objectives
- Explain why voluntary trade benefits both parties and why it leads to allocative efficiency
Getting a Good Deal or Making a Good Deal
Why do people make transactions? Is it because the seller has a surplus of goods or the buyer has a shortage of them? Not exactly. The short answer is that people make transactions because they value the same goods differently at the margin. Remember that marginal analysis involves weighing the benefits and costs of choosing a little bit more or a little bit less of a good.
Suppose Bill loves to snack on apples, while Angie thinks apples are just okay. Suppose they each have a basket containing a dozen apples. Because Bill loves apples, he places a higher value on one more apple than Angie does. That’s what “at the margin” means. Bill is considering one more apple. Suppose Bill thinks another apple would be worth $1.00, while Angie thinks another apple is only worth $0.10. If Bill offered to buy an apple for $0.50 from Angie, would she agree to the transaction?
Since Angie thinks the apple is only worth $0.10, then it would be to her advantage to sell one to Bill and use the $0.40 profit for something she values more than apples. Would Bill benefit from the deal? Since he thinks an apple is worth a dollar, if he could get it for fifty cents, he would be making $0.50 profit. If two parties differ on what some good is worth, they can each benefit from trading the good from the person who values it less to the person who values it more.
If trading one apple is good for both parties, would trading more be better? What motivated the transaction in the first place? It was the difference in opinion between Bill and Angie about what an apple is worth. The value one places on an item depends on tastes in general (in this case it was taste for apples), and how much more of a good a person would like (or how many apples were already consumed). If Angie is very hungry, it’s likely she would value an apple more than normal. Similarly, if Bill had just eaten five apples, he probably would value one more less than he normally values apples.
This suggests another idea we’ve looked at before: the law of diminishing marginal utility. Because of diminishing marginal returns, the more of something you already have, the less one more unit is worth to you. Thus, we can graph Bill’s marginal value curve as shown in Figure 1. Similarly, Angie’s marginal value curve has a similar shape, but it’s lower on the graph to reflect the fact that Angie likes apples less than Bill does.
Try It
Trade and Efficiency
What this means is that the more apples Bill has, the less he values another. Similarly, the less apples Angie has, the more she values one more. Thus, as Angie sells more apples to Bill, her marginal value increases while his decreases. That suggests an answer to the question posed above: Bill and Angie should keep trading apples until they place the same value on them. This is shown in Figure 2, where Bill has bought three apples from Angie. At that point, they will have maximized the benefits from trading apples. Economists describe these benefits from trading as an improvement in allocative efficiency. [1]
Try It
Glossary
- allocative efficiency:
- when benefits of trade are maximized and the mix of goods being produced represents the mix that society most desires
- law of diminishing marginal utility:
- as we consume more of a good or service, the utility we get from additional units of the good or service tend to become smaller than what we received from earlier units
- marginal analysis:
- comparing the benefits and costs of choosing a little more or a little less of a good.
- This page summarizes ideas from Chapter 3 of Armen A. Alchian & William R. Allen, Exchange & Production: Competition, Coordination, & Control, Wadsworth Publishing Company, Belmont, California. 1983. ↵ | 1,170 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/sacmacroeconomics/chapter/trade-and-efficiency/ | pressbooks | pressbooks-0000.json.gz:81479 | https://library.achievingthedream.org/sacmacroeconomics/chapter/trade-and-efficiency/ |
F78Mwmj0pOIYQZzt | ENG 106 | 10 Week 10 – Poems of Protest, Resistance and Empowerment
Leigh Hancock
We live in a turbulent time. America has been at war for most of the past two decades. Income and wealth inequality are at an all-time high in our country, with subsequent surges in homelessness, opiod addiction and percentage of incarcerated citizens (the highest in the developed world). Climate change and covid-19 have each caused huge disruptions for the most vulnerable populations worldwide. Racial inequality and oppression, most profoundly expressed in the Black Lives Matter movement, has finally become visible to almost every American. The chasm between our two main political parties verges on civil war.
So it seems fitting to end this text with a look at poems of protest, resistance and empowerment–then and now. From Walt Whitman’s “O Captain! My Captain!” to Woodie Gutherie’s “Roll on Columbia” to the gospel songs sung by slaves to the fiery poetry of Allen Ginsberg and Audre Lorde, poems and songs have been integral to the fight for justice and liberty…a fight that is far from over.
As the Poetry Foundation states,
Pithy and powerful, poetry is a popular art form at protests and rallies. From the civil rights and women’s liberation movements to Black Lives Matter, poetry is commanding enough to gather crowds in a city square and compact enough to demand attention on social media. Speaking truth to power remains a crucial role of the poet in the face of political and media rhetoric designed to obscure, manipulate, or worse. Such poems call out and talk back to the inhumane forces that threaten from above. They expose grim truths, raise consciousness, and build united fronts. Some insist, as Langston Hughes writes, “That all these walls oppression builds / Will have to go!” Others seek ways to actively “make peace,” as Denise Levertov implores, suggesting that “each act of living” might cultivate collective resistance. All rail against complacency and demonstrate why poetry is necessary and sought after in moments of political crisis. (https://www.poetryfoundation.org/collections/101581/poems-of-protest-resistance-and-empowerment)
(Sadly, despite these inspiring words, the Poetry Foundation itself has come under recent fire for its lack of response to the Black Lives Matter movement, criticism that has resulted in the resignation of its Board President.)
Please choose one or more of the links below to explore and discuss in our discussion forums and journals this week.
- A long list of links to protest poetry: https://poets.org/protest-poetry
- “Poetry in a Time of Protest” by Edwidge Danticat, The New Yorker, https://www.newyorker.com/culture/cultural-comment/poetry-in-a-time-of-protest
- “POems of Resistance: A PRimer” The New York Times, https://www.nytimes.com/2017/04/21/books/review/poltical-poetry-sampler.html
- “The Poems that Poets Turn to in a Time of Strife,” The New York Times, https://www.nytimes.com/2020/06/11/books/poetry-poets-recommendations.html
- “Poetry Foundation Leadership Resigns after Black Lives Matters Comment,” https://www.nytimes.com/2020/06/09/books/poetry-foundation-black-lives-matter.html
- Statement from the Academy of American poets on BLM: https://poets.org/black-lives-matter | 604 | common-pile/pressbooks_filtered | https://openoregon.pressbooks.pub/eng106/chapter/week-10-multiple-interpretations/ | pressbooks | pressbooks-0000.json.gz:6597 | https://openoregon.pressbooks.pub/eng106/chapter/week-10-multiple-interpretations/ |
0PxULCgT3W79LGFf | A 12 Teaching Techniques of the Holidays Cookbook | The Technique
I was looking to improve engagement of students during times of online teaching to save me from “talking at them.” I was using the Best Forestry Practices: A Guide for the Boreal Forest in Ontario government-issued guide in class to reinforce the lecture and textbook, but it felt like it could be so much more. The course textbook is more general, and this document provided relevance to the region where the students live and study. I wanted to give it more intention in the course while moving it into the study time as a way of “flipping the classroom.”
I took some time to create a set of questions that are tied to forest blocks/locations learners would be assigned in my course. For each forest block, learners need to determine interventions for their site, and I thought the questions could help scaffold complicated aspects of this task. The result of this investment in the development of questions connected to the guide is an interactive application of the text that navigates students in different directions based on their answers to questions relevant to their forest block.
The final result
This Interactive Boreal Forest Guided Planning by DzhamalA is licensed under a CC 4.0 international license
How I Use It
After students have reviewed the ways that the course text will be utilized for assignment and testing, they are introduced to the Best Forestry Practices: A Guide for the Boreal Forest in Ontario interactive guide. I then explain how the guide will be used to help them produce a forest management plan. I provide learners with their forest block. Now we can begin to work with it!
The step-by-step instructions are as follows:
- To begin producing their plan/assignment, students select a number from a hat. This determines the site (forest block) they will focus their interventions on.
- Students are then given the “shape” of their forest block – a GIS file provided by me that includes the location of the block they are assigned.
- Students then begin to “find” and assess the block (i.e., go to it online or visit the site in person).
- Once each student knows their location and their forest blocks state they are responsible for, they are ready to do the branching activity and begin to answer questions contained within it.
To aid learners’ independent use of the [H5P] interactive guide, the guide begins with an interactive video that outlines what they need to do at each step in their plan development within the branching activities provided. This video includes knowledge checks at a few key points to assure the students are ready to start. The rest is up to each learner!
Feedback from Learners
An interactive technique where the students can see the real-world impact of implementing a silvicultural intervention is something I am passionate about. Hands-on learning and relating to real-world experiences always leaves a longer lasting impact in learners’ perspectives and knowledge than mere text work.
In discussions with students that I had presented this to, it became clear that their active involvement and use of the interactive guide would enhance knowledge retention. This discussion sparked a greater interest in finding solutions “outside the box” for local challenges that “hit home.”
A Short Task to Challenge You!
Let see if you have enough information to initiate your holiday plans…
One Final Task
Is this something you can use in your classroom? How might you utilize it? If you share your results somewhere on social media, share a link to this lesson for context. | 772 | common-pile/pressbooks_filtered | https://ecampusontario.pressbooks.pub/12techniquesoftheholidays/chapter/2022-lesson3/ | pressbooks | pressbooks-0000.json.gz:21380 | https://ecampusontario.pressbooks.pub/12techniquesoftheholidays/chapter/2022-lesson3/ |
58d2e3EakoO2nVzA | 5: Stereochemistry at Tetrahedral Centers | 5: Stereochemistry at Tetrahedral Centers
After you have completed Chapter 5, you should be able to
- fulfill all of the detailed objectives listed under each individual section.
- use molecular models in solving problems on stereochemistry.
- solve road-map problems that include stereochemical information.
- define, and use in context, the new key terms.
This chapter introduces the concept of chirality, and discusses the structure of compounds containing one or two chiral centers. A convenient method of representing the three-dimensional arrangement of the atoms in chiral compounds is explained; furthermore, throughout the chapter , considerable emphasis is placed on the use of molecular models to assist in the understanding of the phenomenon of chirality. The chapter continues with an examination of stereochemistry—the three-dimensional nature of molecules. The subject is introduced using the experimental observation that certain substances have the ability to rotate plane-polarized light. Finally, certain reactions of alkenes are re-examined in the light of the new material encountered in this chapter.
-
- 5.2: Optical Activity
- Identifying and distinguishing enantiomers is inherently difficult, since their physical and chemical properties are largely identical. Fortunately, a nearly two hundred year old discovery by the French physicist Jean-Baptiste Biot has made this task much easier. This discovery disclosed that the right- and left-handed enantiomers of a chiral compound perturb plane-polarized light in opposite ways. This perturbation is unique to chiral molecules, and has been termed optical activity.
-
- 5.4: Enantiomers and the Tetrahedral Carbon
- Stereoisomers are isomers that differ in spatial arrangement of atoms, rather than order of atomic connectivity. One of the most interesting types of isomer is the mirror-image stereoisomer, a non-superimposable set of two molecules that are mirror images of one another. The existence of these molecules are determined by a a concept known as chirality.
-
- 5.8: Meso Compounds
- A meso compound is an achiral compound that has chiral centers. A meso compound contains an internal plane of symmetry which makes it superimposable on its mirror image and is optically inactive although it contains two or more stereocenters. Remember, an internal plane of symmetry was shown to make a molecule achiral.
-
- 5.9: Racemic Mixtures and the Resolution of Enantiomers
- A racemic mixture is a 50:50 mixture of two enantiomers. Because they are mirror images, each enantiomer rotates plane-polarized light in an equal but opposite direction and is optically inactive. If the enantiomers are separated, the mixture is said to have been resolved. A common experiment in the laboratory component of introductory organic chemistry involves the resolution of a racemic mixture.
Thumbnail: Two enantiomers of a generic amino acid that are chiral. (Public Domain; unknonw author via Wikipedia ) | 583 | common-pile/libretexts_filtered | https://chem.libretexts.org/Courses/Alma_College/Organic_Chemistry_I_(Alma_College)/05%3A_Stereochemistry_at_Tetrahedral_Centers | libretexts | libretexts-0000.json.gz:16639 | https://chem.libretexts.org/Courses/Alma_College/Organic_Chemistry_I_(Alma_College)/05%3A_Stereochemistry_at_Tetrahedral_Centers |
Je_3AUcAVrpMdvtA | 1.2: Atomic Structure - The Nucleus | 1.2: Atomic Structure - The Nucleus
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Objective
After completing this section, you should be able to describe the basic structure of the atom.
Key Terms
Make certain that you can define, and use in context, the key terms below.
- atomic number
- atomic weight
- electron
- mass number
- neutron
- proton
The Nuclear Atom
The precise physical nature of atoms finally emerged from a series of elegant experiments carried out between 1895 and 1915. The most notable of these achievements was Ernest Rutherford's famous 1911 alpha-ray scattering experiment, which established that:
- Almost all of the mass of an atom is contained within a tiny (and therefore extremely dense) nucleus which carries a positive electric charge whose value identifies each element and is known as the atomic number of the element.
- Almost all of the volume of an atom consists of empty space in which electrons , the fundamental carriers of negative electric charge, reside. The extremely small mass of the electron (1/1840 th the mass of the hydrogen nucleus) causes it to behave as a quantum particle, which means that its location at any moment cannot be specified; the best we can do is describe its behavior in terms of the probability of its manifesting itself at any point in space. It is common (but somewhat misleading) to describe the volume of space in which the electrons of an atom have a significant probability of being found as the electron cloud . The latter has no definite outer boundary, so neither does the atom. The radius of an atom must be defined arbitrarily, such as the boundary in which the electron can be found with 95% probability. Atomic radii are typically 30-300 pm.
The nucleus is itself composed of two kinds of particles. Protons are the carriers of positive electric charge in the nucleus; the proton charge is exactly the same as the electron charge, but of opposite sign. This means that in any [electrically neutral] atom, the number of protons in the nucleus (often referred to as the nuclear charge ) is balanced by the same number of electrons outside the nucleus. The other nuclear particle is the neutron . As its name implies, this particle carries no electrical charge. Its mass is almost the same as that of the proton. Most nuclei contain roughly equal numbers of neutrons and protons, so we can say that these two particles together account for almost all the mass of the atom.
Because the electrons of an atom are in contact with the outside world, it is possible for one or more electrons to be lost, or some new ones to be added. The resulting electrically-charged atom is called an ion .
Atomic Number (Z)
What single parameter uniquely characterizes the atom of a given element? It is not the atom's relative mass, as we will see in the section on isotopes below. It is, rather, the number of protons in the nucleus, which we call the atomic number and denote by the symbol Z . Each proton carries an electric charge of +1, so the atomic number also specifies the electric charge of the nucleus. In the neutral atom, the Z protons within the nucleus are balanced by Z electrons outside it.
Atomic numbers were first worked out in 1913 by Henry Moseley, a young member of Rutherford's research group in Manchester.
Moseley searched for a measurable property of each element that increases linearly with atomic number. He found this in a class of X-rays emitted by an element when it is bombarded with electrons. The frequencies of these X-rays are unique to each element, and they increase uniformly in successive elements. Moseley found that the square roots of these frequencies give a straight line when plotted against Z; this enabled him to sort the elements in order of increasing atomic number.
You can think of the atomic number as a kind of serial number of an element, commencing at 1 for hydrogen and increasing by one for each successive element. The chemical name of the element and its symbol are uniquely tied to the atomic number; thus the symbol "Sr" stands for strontium, whose atoms all have Z = 38.
Mass Number (A)
The mass number equals the sum of the numbers of protons and the number of neutrons in the nucleus. It is sometimes represented by the symbol \(A\), so
\[A = Z + N \nonumber \] A = Z + N
in which \(Z\) is the atomic number and \(N\) is the neutron number .
Elements
To date, about 115 different elements have been discovered; by definition, each is chemically unique. To understand why they are unique, you need to understand the structure of the atom (the fundamental, individual particle of an element) and the characteristics of its components. Atoms consist of electrons, protons, and neutrons. Although this is an oversimplification that ignores the other subatomic particles that have been discovered, it is sufficient for discussion of chemical principles. Some properties of these subatomic particles are summarized in Table \(\PageIndex{1}\), which illustrates three important points:
- Electrons and protons have electrical charges that are identical in magnitude but opposite in sign. Relative charges of −1 and +1 are assigned to the electron and proton, respectively.
- Neutrons have approximately the same mass as protons but no charge. They are electrically neutral.
- The mass of a proton or a neutron is about 1836 times greater than the mass of an electron. Protons and neutrons constitute the bulk of the mass of atoms.
The discovery of the electron and the proton was crucial to the development of the modern model of the atom and provides an excellent case study in the application of the scientific method. In fact, the elucidation of the atom’s structure is one of the greatest detective stories in the history of science.
| Particle | Mass (g) | Atomic Mass (amu) | Electrical Charge (coulombs) | Relative Charge |
|---|---|---|---|---|
| electron | \(9.109 \times 10^{-28}\) | 0.0005486 | −1.602 × 10 −19 | −1 |
| proton | \(1.673 \times 10^{-24}\) | 1.007276 | +1.602 × 10 −19 | +1 |
| neutron | \(1.675 \times 10^{-24}\) | 1.008665 | 0 | 0 |
In most cases, the symbols for the elements are derived directly from each element’s name, such as C for carbon, U for uranium, Ca for calcium, and Po for polonium. Elements have also been named for their properties [such as radium (Ra) for its radioactivity], for the native country of the scientist(s) who discovered them [polonium (Po) for Poland], for eminent scientists [curium (Cm) for the Curies], for gods and goddesses [selenium (Se) for the Greek goddess of the moon, Selene], and for other poetic or historical reasons. Some of the symbols used for elements that have been known since antiquity are derived from historical names that are no longer in use; only the symbols remain to indicate their origin. Examples are Fe for iron, from the Latin ferrum ; Na for sodium, from the Latin natrium ; and W for tungsten, from the German wolfram . Examples are in Table \(\PageIndex{2}\).
| Element | Symbol | Derivation | Meaning |
|---|---|---|---|
| antimony | Sb | stibium | Latin for “mark” |
| copper | Cu | cuprum | from Cyprium, Latin name for the island of Cyprus, the major source of copper ore in the Roman Empire |
| gold | Au | aurum | Latin for “gold” |
| iron | Fe | ferrum | Latin for “iron” |
| lead | Pb | plumbum | Latin for “heavy” |
| mercury | Hg | hydrargyrum | Latin for “liquid silver” |
| potassium | K | kalium | from the Arabic al-qili, “alkali” |
| silver | Ag | argentum | Latin for “silver” |
| sodium | Na | natrium | Latin for “sodium” |
| tin | Sn | stannum | Latin for “tin” |
| tungsten | W | wolfram | German for “wolf stone” because it interfered with the smelting of tin and was thought to devour the tin |
Recall that the nuclei of most atoms contain neutrons as well as protons. Unlike protons, the number of neutrons is not absolutely fixed for most elements. Atoms that have the same number of protons, and hence the same atomic number, but different numbers of neutrons are called isotopes. All isotopes of an element have the same number of protons and electrons, which means they exhibit the same chemistry. The isotopes of an element differ only in their atomic mass, which is given by the mass number (A), the sum of the numbers of protons and neutrons.
Carbon Isotopes
The element carbon (C) has an atomic number of 6, which means that all neutral carbon atoms contain 6 protons and 6 electrons. In a typical sample of carbon-containing material, 98.89% of the carbon atoms also contain 6 neutrons, so each has a mass number of 12. An isotope of any element can be uniquely represented as \(^A_Z X\), where X is the atomic symbol of the element. The isotope of carbon that has 6 neutrons is therefore \(_6^{12} C\). The subscript indicating the atomic number is actually redundant because the atomic symbol already uniquely specifies Z. Consequently, \(_6^{12} C\) is more often written as 12 C, which is read as “carbon-12.” Nevertheless, the value of Z is commonly included in the notation for nuclear reactions because these reactions involve changes in Z.
In addition to \(^{12}C\), a typical sample of carbon contains 1.11% \(_6^{13} C\) ( 13 C), with 7 neutrons and 6 protons, and a trace of \(_6^{14} C\) ( 14 C), with 8 neutrons and 6 protons. The nucleus of 14 C is not stable, however, but undergoes a slow radioactive decay that is the basis of the carbon-14 dating technique used in archaeology. Many elements other than carbon have more than one stable isotope; tin, for example, has 10 isotopes. The properties of some common isotopes are in Table \(\PageIndex{3}\).
| Element | Symbol | Atomic Mass (amu) | Isotope Mass Number | Isotope Masses (amu) | Percent Abundances (%) |
|---|---|---|---|---|---|
| hydrogen | H | 1.0079 | 1 | 1.007825 | 99.9855 |
| 2 | 2.014102 | 0.0115 | |||
| boron | B | 10.81 | 10 | 10.012937 | 19.91 |
| 11 | 11.009305 | 80.09 | |||
| carbon | C | 12.011 | 12 | 12 (defined) | 99.89 |
| 13 | 13.003355 | 1.11 | |||
| oxygen | O | 15.9994 | 16 | 15.994915 | 99.757 |
| 17 | 16.999132 | 0.0378 | |||
| 18 | 17.999161 | 0.205 | |||
| iron | Fe | 55.845 | 54 | 53.939611 | 5.82 |
| 56 | 55.934938 | 91.66 | |||
| 57 | 56.935394 | 2.19 | |||
| 58 | 57.933276 | 0.33 | |||
| uranium | U | 238.03 | 234 | 234.040952 | 0.0054 |
| 235 | 235.043930 | 0.7204 | |||
| 238 | 238.050788 | 99.274 |
Sources of isotope data: G. Audi et al., Nuclear Physics A 729 (2003): 337–676; J. C. Kotz and K. F. Purcell, Chemistry and Chemical Reactivity, 2nd ed., 1991.
Example \(\PageIndex{1}\)
An element with three stable isotopes has 82 protons. The separate isotopes contain 124, 125, and 126 neutrons. Identify the element and write symbols for the isotopes.
Given : number of protons and neutrons
Asked for : element and atomic symbol
Strategy :
- Refer to the periodic table and use the number of protons to identify the element.
- Calculate the mass number of each isotope by adding together the numbers of protons and neutrons.
- Give the symbol of each isotope with the mass number as the superscript and the number of protons as the subscript, both written to the left of the symbol of the element.
Solution :
A The element with 82 protons (atomic number of 82) is lead: Pb.
B For the first isotope, A = 82 protons + 124 neutrons = 206. Similarly, A = 82 + 125 = 207 and A = 82 + 126 = 208 for the second and third isotopes, respectively. The symbols for these isotopes are \(^{206}_{82}Pb\), \(^{207}_{82}Pb\), and \(^{208}_{82}Pb\), which are usually abbreviated as \(^{206}Pb\), \(^{207}Pb\), and \(^{208}Pb\).
Exercise \(\PageIndex{1}\)
Identify the element with 35 protons and write the symbols for its isotopes with 44 and 46 neutrons.
- Answer
-
\(\ce{^{79}_{35}Br}\) and \(\ce{^{81}_{35}Br}\) or, more commonly, \(\ce{^{79}Br}\) and \(\ce{^{81}Br}\).
Summary
The atom consists of discrete particles that govern its chemical and physical behavior. Each atom of an element contains the same number of protons, which is the atomic number ( Z ). Neutral atoms have the same number of electrons and protons. Atoms of an element that contain different numbers of neutrons are called isotopes . Each isotope of a given element has the same atomic number but a different mass number ( A ), which is the sum of the numbers of protons and neutrons. The relative masses of atoms are reported using the atomic mass unit ( amu ), which is defined as one-twelfth of the mass of one atom of carbon-12, with 6 protons, 6 neutrons, and 6 electrons. | 2,909 | common-pile/libretexts_filtered | https://chem.libretexts.org/Courses/Smith_College/Organic_Chemistry_(LibreTexts)/01%3A_Structure_and_Bonding/1.02%3A_Atomic_Structure_-_The_Nucleus | libretexts | libretexts-0000.json.gz:26137 | https://chem.libretexts.org/Courses/Smith_College/Organic_Chemistry_(LibreTexts)/01%3A_Structure_and_Bonding/1.02%3A_Atomic_Structure_-_The_Nucleus |
qul6oUw0tFrK5z6m | 20.26: Sugar Consumption in the US Diet | 20.26: Sugar Consumption in the US Diet
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Learning Objectives
- Sugar Consumption in the US Diet between 1822 and 2005
Research conducted by
Stephan Guyenet and Jeremy Landen
Case study prepared by
Robert F. Houser and Georgette Baghdady
Overview
Sugar has many forms: cane sugar, beet sugar, honey, molasses, fruit juice concentrate, glucose, sucrose, fructose, high-fructose corn syrup, maple syrup, brown rice syrup, barley malt syrup, agave nectar, to list a few. High-fructose corn syrup, in particular, was introduced into the US food industry in the early \(1970s\) and has become ubiquitous in processed foods and soft drinks. Many of the added sugars in packaged foods and beverages could be considered "hidden sugar" because, if we do not examine the ingredients list on food labels or know sugar's many aliases, we are most likely unaware of how much sugar we consume each day.
To explore sugar consumption trends in the US, researchers Stephan Guyenet and Jeremy Landen compiled data on caloric sweetener sales spanning \(184\) years. They extracted annual caloric sweetener sales per capita for \(1822\) to \(1908\) from US Department of Commerce and Labor reports, and for \(1909\) to \(2005\) from the US Department of Agriculture (USDA) web site. The researchers adjusted the sales data for post-production losses using the USDA's \(1970-2005\) loss estimate of \(28.8\) percent to obtain reasonable estimates of annual per capita consumption of added sugars. Post-production losses of a food commodity occur at the retail, foodservice and consumer levels from, for example, spoilage, pests, cooking losses and plate waste.
Guyenet presents a striking graph and regression analysis of sugar consumption in the US from \(1822\) to \(2005\) in a blog to promote awareness and discussion.
Questions to Answer
Do different time periods between \(1822\) and \(2005\) reveal different trends in sugar consumption in the US diet? Can a regression graph be used to make predictions outside the range of the study data?
Design Issues
The data represent added caloric sugars such as cane sugar, high-fructose corn syrup and maple syrup, not naturally occurring sugars such as those in fruits and vegetables. Thus the data do not represent total sugar consumption. The data are not direct measures of consumption, but rather estimates derived from sales figures by adjusting for losses before consumption. The adjustment, applied across all years, is based on the USDA loss estimate from \(1970-2005\), which may or may not underestimate sugar consumption in earlier time periods.
Descriptions of Variables
| Variable | Description |
| year | All years from 1822 to 2005 |
| sugar_ consum | Estimated consumption of added sugars in the US diet in pounds per year per person |
Data Files
Sugar.xls
Links
By 2606, the US Diet will be 100 Percent Sugar, a blog by Stephan Guyenet
How to Spot Added Sugar on Food Labels
Dietary Sugars Intake and Cardiovascular Health: A Scientific Statement From the American Heart Association
Sugar: The Bitter Truth, a lecture by Robert H. Lustig
60 Minutes: Is Sugar Toxic?
References
- Johnson, R. K., Appel, L. J., Brands, M., Howard, B. V., Lefevre, M., Lustig, R. H., Sacks, F., Steffen, L. M., Wylie-Rosett, J. (2009). Dietary sugars intake and cardiovascular health: A scientific statement from the American Heart Association. Circulation, 120, 1011-1020. | 712 | common-pile/libretexts_filtered | https://stats.libretexts.org/Courses/Cerritos_College/Introduction_to_Statistics_with_R/20%3A_Case_Studies_and_Data/20.26%3A_Sugar_Consumption_in_the_US_Diet | libretexts | libretexts-0000.json.gz:9952 | https://stats.libretexts.org/Courses/Cerritos_College/Introduction_to_Statistics_with_R/20%3A_Case_Studies_and_Data/20.26%3A_Sugar_Consumption_in_the_US_Diet |
VO43R3I_vBeL6Hzy | OER by Discipline Guide: University of Calgary | Cumming School of Medicine
Department of Anesthesiology, Perioperative and Pain Medicine (Clinical)
Palliative Care
Health Promotion in Health Care: Vital Theories and Research
This open access book first discusses the theory of health promotion and vital concepts. It then presents updated evidence-based health promotion approaches in different populations (people with chronic diseases, cancer, heart failure, dementia, mental disorders, long-term ICU patients, elderly individuals, families with newborn babies, palliative care patients) and examines different health promotion approaches integrated into primary care services.
Licence: CC BY 4.0
No suggested OER currently available for the following subjects:
- Acute and chronic pain
- Anesthesiology
- Critical care
- Perioperative
- Simulation
- Vascular
Please refer to the Libraries and Cultural Resources (LCR) Staff Directory to connect with a librarian supporting this subject area.
Know of an open educational resource (OER) not listed?
Contact us at<EMAIL_ADDRESS>Already using an OER? Have you adapted or created an OER?
Let us know by completing the OER Adoption and Creation Sharing Form | 213 | common-pile/pressbooks_filtered | https://pressbooks.openeducationalberta.ca/oerguideucalgary/chapter/anesthesiology-perioperative-pain-medicine-clinical/ | pressbooks | pressbooks-0000.json.gz:51311 | https://pressbooks.openeducationalberta.ca/oerguideucalgary/chapter/anesthesiology-perioperative-pain-medicine-clinical/ |
MZ72RAEg0zYzMlpz | MHCC Biology 112: Biology for Health Professions | 60 Changes in Enzyme Activity
It would seem ideal to have a scenario in which all of an organism’s enzymes existed in abundant supply and functioned optimally under all cellular conditions, in all cells, at all times. However, this is not true for a variety of reasons. First, it would require a lot of energy to produce all an organism’s enzymes all the time. Also, cellular needs and conditions constantly vary from cell to cell, and change within individual cells over time. The required enzymes of stomach cells differ from those of fat storage cells, skin cells, blood cells, and nerve cells. Furthermore, a digestive organ cell works much harder to process and break down nutrients during the time that closely follows a meal compared with many hours after a meal. As these cellular demands and conditions vary, so must the amounts and functionality of different enzymes.
Since the rates of biochemical reactions are controlled by activation energy, and enzymes lower and determine activation energies for chemical reactions, the relative amounts and functioning of the variety of enzymes within a cell ultimately determine which reactions will proceed and at what rates. This determination is tightly controlled in cells.
Regulation
Enzymes can also be regulated in ways that either promote or reduce enzyme activity. There are many kinds of molecules that inhibit or promote enzyme function, and various mechanisms by which they do so.
- In some cases of enzyme inhibition, an inhibitor molecule is similar enough to a substrate that it can bind to the active site and simply block the substrate from binding.
- In other cases, an inhibitor molecule binds to the enzyme in a location other than the active site, called an allosteric site, but still manages to block substrate binding to the active site (Figure 4).
- Some inhibitor molecules bind to enzymes in a location where their binding causes a change in the shape of the enzyme that makes the enzyme less likely to bind to its substrate.
- There are also activator molecules that can increase the ability of an enzyme to bind to its substrate.
Cofactors and Coenzymes
Many enzymes do not work optimally, or even at all, unless bound to other specific non-protein helper molecules. They may bond either temporarily through ionic or hydrogen bonds, or permanently through stronger covalent bonds. Binding to these molecules promotes optimal shape and function of their respective enzymes – they activate the enzyme. Two examples of these types of helper molecules are cofactors and coenzymes. Cofactors are inorganic ions such as ions of iron and magnesium. Coenzymes are organic helper molecules, those with a basic atomic structure made up of carbon and hydrogen. Like enzymes, these molecules participate in reactions without being changed themselves and are ultimately recycled and reused. Vitamins are the source of coenzymes. Some vitamins are the precursors of coenzymes and others act directly as coenzymes. Vitamin C is a direct coenzyme for multiple enzymes that take part in building the important connective tissue, collagen. Therefore, enzyme function is, in part, regulated by the abundance of various cofactors and coenzymes, which may be supplied by an organism’s diet or, in some cases, produced by the organism.
Effect of environmental conditions
Enzyme activity is subject to influences of the local environment. In a cold environment, enzymes function more slowly because the molecules are moving more slowly. The substrate bumps into the enzyme less frequently. As the temperature increases, molecules move more quickly, so the enzyme functions at a higher rate. Increasing temperature generally increases reaction rates, enzyme-catalyzed or otherwise. You may have noticed that sugar dissolves faster in hot coffee than in cold ice tea – this is because the molecules are moving more quickly in hot coffee, which increases the rate of the reaction. However, temperatures that are too high will reduce the rate at which an enzyme catalyzes a reaction. This is because hot temperatures will eventually cause the enzyme to denature, an irreversible change in the three-dimensional shape and therefore the function of the enzyme (Figure 5).
Denaturation is caused by the breaking of the bonds that hold the enzyme together in its three-dimensional shape. Heat can break hydrogen and ionic bonds, which disrupts the shape of the enzyme and will change the shape of the active site. Cold temperatures do not denature enzymes because cold does not cause chemical bonds to break.
Enzymes are suited to function best within a certain temperature, pH, and salt concentration range. In addition to high temperatures, extreme pH and salt concentrations can cause enzymes to denature. Both acidic and basic pH can cause enzymes to denature because the presence of extra H+ ions (in an acidic solution) or OH- ions (in a basic solution) can modify the chemical structure of the amino acids forming the protein, which can cause the chemical bonds holding the three-dimensional structure of the protein to break. High salt concentrations can also cause chemical bonds within the protein to break in a similar matter.
Typically, enzymes function optimally in the environment where they are typically found and used. For example, the enzyme amylase is found in saliva, where it functions to break down starch (a polysaccharide – carbohydrate chain) into smaller sugars. Note that in this example, amylase is the enzyme, starch is the substrate, and smaller sugars are the product. The pH of saliva is typically between 6.2 and 7.6, with roughly 6.7 being the average. The optimum pH of amylase is between 6.7 and 7.0, which is close to neutral (Figure 3). The optimum temperature for amylase is close to 37ºC (which is human body temperature).
References
Unless otherwise noted, images on this page are licensed under CC-BY 4.0 by OpenStax.
Text adapted from: OpenStax, Concepts of Biology. OpenStax CNX. May 18, 2016 http://cnx.org/contents/b3c1e1d2-839c-42b0-a314-e119a8aafbdd@9.10 | 1,255 | common-pile/pressbooks_filtered | https://openoregon.pressbooks.pub/mhccbiology112/chapter/changes-in-enzyme-activity/ | pressbooks | pressbooks-0000.json.gz:67569 | https://openoregon.pressbooks.pub/mhccbiology112/chapter/changes-in-enzyme-activity/ |
tqcZNLh9ooMP8a4t | Foundations of Learning and Instructional Design Technology | 42
Tadd Farmer and Richard E. West
Editor’s Note: The following article was originally published in Educational Technology and is used here by permission of the editor. For more information on open badges, “Open Badges: trusted, portable digital credentials, Doug Belshaw” is an excellent presentation from Doug Belshaw, who worked on the original project. Also, the K–12 BadgeChat on Flipboard from the Open Badge Alliance contains many curated articles and information related to K–12 use of open badges.
Farmer, T., & West, R. E. (2016). Opportunities and challenges with digital open badges. Educational Technology, 56(5), 45–48. Retrieved from http://www.academia.edu/29863552/Opportunities_and_Challenges_with_Digital_Open_Badges
In 2011, Arne Duncan, Secretary of the U.S. Department of Education, gave a speech at the MacArthur Foundation Digital Media and Lifelong Learning Competition and detailed the need to establish certifications of achievement recognizing informal learning experiences. He said, “Today’s technology-enabled, information-rich, deeply interconnected world means learning not only can—but should—happen anywhere, anytime. We need to recognize these experiences” (Duncan, 2011, para. 14). Informal learning settings such as web-based and blended learning environments, after-school and extracurricular activities, and vocational and work-based training programs are becoming increasingly prevalent. However, participants in these environments have difficulty being recognized for the competencies they develop.
This inability to recognize learning in informal contexts is one of many concerns with traditional assessing approaches. A second concern is that traditional credentials are not always effective communicators of a student’s skill or knowledge. When a student is given an “A” at the conclusion of a course, what does that grade symbolize? How easy is it for a student, parent, or teacher to look inside that grade to discern the specific competencies acquired by a particular student? On a larger scale, how easy is it for a potential employer to analyze the degree and GPA of a prospective employee and understand the full range of that prospect’s skills and competencies? Such indicators fail to provide a transparent picture of an individual’s experience and qualifications.
These two challenges of how to recognize and reward informal learning, and how to increase transparency in traditional grading practices are two credentialing challenges begging for a solution. In the last several years, advances in the field of microcrendentialing, specifically digital badging, has shown promise in solving these assessment challenges.
What are Digital and Open Badges?
The definition for digital and open badges includes both concepts of structure and function for the users. Structurally speaking, digital badges are small digital images that represent an individual’s learning within a specific domain. These images are embedded with rich metadata that increases transparency into what is actually learned (Gamrat, Zimmerman, Dudek, & Peck, 2014; Gamrat & Zimmerman, 2015). This metadata could include information about the badge issuer (institution name, date of issue, rubric and requirements for the badge) and badge earner (name, evidence of learning, and feedback from the issuer), providing a more transparent picture of what has been learned and the observable evidence of that learning.
Open badges are a unique type of digital badge with additional affordances built into the technology that allow for the credential to be integrated into any compatible learning or portfolio system. While some digital badges are useful indicators of learning within a closed system (e.g. Khan Academy, Duolingo), open badges can be exported into open backpacks that collect and display these microcredentials from many different formal and informal learning systems.
Because of their digital and open affordances, open badges can also serve a variety of functions, including as a map of learning pathways or trajectories (Bowen & Thomas, 2014; Newby, Wright, Besser, & Beese, 2015; Gamrat & Zimmerman, 2015), “descriptions of merit” (Rughinis & Matei, 2013), signposts of past and future learning (Rughinis & Matei, 2013), a reward or status symbol (Newby et al., 2015), promoters of motivation and self-regulation (Newby et al., 2015; Randall, Harrison, & West, 2013), “tokens of accomplishment” (O’Byrne, Schenke, Willis, & Hickey, 2015), a learning portfolio or repository (Gamrat et al., 2014), and a goal-setting support (Gamrat & Zimmerman, 2015).
Benefits of Open Badges
This long list of functions served by open badges illuminates some of the major benefits and affordances of badges, including positive effects on motivation, guidance, and recognition.
Using digital badges as an incentive for learning or performance is a common practice. Upon completion of a badge, learners are awarded a badge that becomes an outward symbol of a successful learning experience. Careful badge design could even create appeal for a learner’s intrinsic motivation by rewarding effort and improvement instead of performance (Jovanovic, Devedzic, 2014), and by providing choices for learners, thus increasing their autonomy and self-direction (West & Randall, 2016).
In fact, many organizations with badging structures include self-direction as a major component. The Sustainable Agriculture & Food Systems Major (SA&FS) at University of California, Davis allows students to create completely customized badges (content and criteria) that will recognize an individual’s learning and achievements across various learning contexts (University of California, Davis, 2014).
Additionally, as badges increase learner autonomy and choice, they can also improve how we guide and scaffold students to new, engaging, and personalized learning experiences that are relevant to their preferences, abilities, and aptitudes. Indeed, Green, Facer, Rudd, Dillon, and Humphreys (2005) argued that there were four key aspects of personalized learning through digital technologies, including giving learners choices, recognizing different forms of skills and knowledge, and learner-focused assessment. Open badges address these key attributes of personalized learning by increasing learning options, assessing discrete skills at a micro level, and credentialing learning both within and without traditional formal institutions. These badges can then be organized into learning paths that provide guidance to learners in particular domains. An example is from Codeschool (https://www.codeschool.com/paths), which uses paths to direct students through micro-learning activities within certain areas. In this way, badges help scaffold students in taking ownership of their learning process.
Digital badges not only illuminate the learning pathways for future learning, but can also recognize learning experiences that previously have not been easily acknowledged through a credential. By design, badges are microcredentials that display learning discrete competencies along with relevant data. Mehta, Hull, Young, & Stoller, (2013) suggested that this could potentially offer a solution to the medical training profession by helping medical students gain important competencies while staying current on their learning. He suggested that medical students could earn a badge for a specific procedure, test, or even medical explanation. That badge would be displayed on the learner’s profile and would reflect their learning across a variety of settings. Additionally, each badge could include an expiration date that would ensure that medical professionals were current in their training, a feature that has also been suggested for other domains such as teacher education (Randall et al., 2013).
Examples in Open Badging
Over the last several years, open badges have attracted attention as a way to solve many difficult educational problems. As of March 2013, Mozilla Open Badges, a major host of the badging community, had 700 unique registered issuers that linked to over 75,000 digital badges (Gibson, Ostashewski, Flintoff, Grant, & Knight, 2015). Other research estimates that over 2,000 organizations have currently implemented badging into their learning environments (Jovanovic & Devedzic, 2014). From analyzing web search trends in more recent years, we can assume that these numbers have only increased.
The attention received by digital badges is increasing due to examples of successful badging programs in secondary and higher education environments. Teacher Learning Journeys (TLJ) developed through a partnership between Penn State University and NASA, National Aeronautics, and the National Science Teachers Association (NSTA) provides an example of a successful badging program for inservice teachers. This partnership worked together to create 63 professional development activities as part of the TLJ for each teacher. Teachers were asked to browse the various activities and plan which activities they wanted to participate in to develop their teaching abilities. Additionally, teachers were offered two levels of competencies for each activity: badges and stamps (a lower achievement). Through a careful case study of program participants in TLJ, researchers discovered that the badging structure provided learning pathways that allowed teachers to self-regulate their professional development and learning. Teachers were given options of various content badges, and could choose the level of performance they wanted to develop within the desired content. This program included the principle of self-regulation that are important characteristics in establishing higher levels of motivation (Pink, 2011).
Purdue University’s badging system, known as Passport, allows faculty members create, design, and issue their own badges in support of all learning (Bowen & Thomas, 2014). Passport has been a successful tool in establishing badges for intercultural learning courses, educational technology courses, and even for LinkedIn proficiencies through the university’s career center. By enabling faculty members to become badge creators, Purdue is encouraging the development of an assessment culture based on transparency, competency, and recognition.
Institutions of higher learning are not the only organizations experimenting with open badges. Primary and secondary schools are also beginning to implement badging systems to motivate, direct, and recognize student learning. The MOUSE Squad, an organization aimed at helping disadvantaged students, utilizes badges to motivate, assess, and recognize student learning both in school and with after school programs. A case study of the program outlined the successful experience of a young girl named Zainab who immigrated to the United States from Nigeria at age 12. Through engaging in the MOUSE program, Zainab gained technological skills in a social collaborative experience to create a device for the visually impaired that would alert them when food was placed on their plate. The skills and competencies developed by Zainab were represented as badges on her college application and helped her earn a full scholarship to the University of Virginia (O’Byrne et al., 2015).
Badges can recognize learning beyond the physical walls of an organization as well as beyond the typical organizational schedule. One leader in the area of digital badges, although these badges are not open and compliant with the Open Badge Infrastructure, is Khan Academy. In addition to course content, Khan Academy uses a digital badge structure that acts as learning pathways for future learning as well as recognition of skills and competencies previously developed. In addition to concrete content skills, Khan Academy is notable for its collection of badges issued for “soft skills” such as listening, persistence, and habit formation (“Badges,” 2015)—an idea that may begin to spread to open badge systems as well.
Challenges in Digital Badges
While digital badges offer promise for solving some difficult educational challenges, critics have pointed out several concerns, particularly with issues of scope, awareness, and assessment practices.
With so many institutions experimenting with badging systems, it is possible that the flood of badges is undermining the efforts to use badges as an effective assessment tool. In their assessment of badges, West and Randall (2016) hypothesized that unless the badging community can show how badges can be a rigorous and meaningful assessment tool, the idea of badges will fade away without making any difference on the educational environment. This flood of badges, particularly “lightweight” badges, can clutter the badging landscape and hinder the ability for the end user (e.g. employer, academic institution, etc.) to determine the value and quality of badges. Therefore, the responsibility of the badging community is to create and issue badges that are rigorous and meaningful.
Another challenge to open badges is the struggle to be recognized outside of their native badging ecosystem. In badging, an ecosystem is made up of badge developers, earners, issuers, and end users that interact with each other to learn, display, and recognize competencies. Ecosystems can be local in nature, where badges are intended to be used within an individual’s learning space, or global where badges are designed to be displayed and recognized beyond the institution’s community. While both badging ecosystems can serve an important purpose, creating a global badging ecosystem requires organizations outside the institution to recognize and accept the badge performance and assessment. This recognition is difficult to achieve with institutions who have standards, requirements, and objectives that often do not align. However, because of the portability of the open badge technology, it is possible for like-minded institutions of learning to form consortiums where badges could hold value with peer institutions within the consortium. Professional organizations with a vested interest in those skills might consider endorsing these badges to give them increased weight and importance (Ma, 2015).
Much like any start-up organization trying to enter into a new market, new ideas, such as open badges, require brand awareness by consumers to begin gaining cultural acceptance. Generally speaking, consumers must be made aware through positive interactions with a product or idea before they are willing to embrace it. Although open badges are becoming more common in work and educational settings, a lack of awareness about badges persists. Decision makers in government, business, and education appear to be generally unaware of the potential of badges to motive, direct, and recognize learning.
The inability of badges to be diffused and implemented into a wider educational context may be due to a larger struggle between traditional and competency-based grading. Competency demands mastery of content and allows for the variables of time, resources, and location of learning to vary (Reigeluth & Garfinkle, 1994). Traditional approaches to assessment allow for student’s learning to vary while keeping other variables constant. Open badges can be used in a competency approach to assessment that encourages students to redo and rework problems until they have mastered the skill and fulfilled the requirements for the badge.
Conclusion
The inability to effectively recognize informal and formal learning competencies in traditional business and educational contexts begs for new ways of assessment and new forms of credentials. Well designed digital open badging systems offer potential solutions. While badges are becoming increasingly common, proponents of widespread adoption of badges face difficult challenges in creating common norms around the scope for badges and the learning they represent, how to successfully build badge awareness and credibility that extends beyond institutional boundaries, and how to effectively navigate to more competency-based styles of assessment. What is needed for an innovation like open badges to be successful, at this stage, are additional examples of effective badging practices, along with rigorous research into the principles of quality badging. Scholars could study how teachers, learners, and organizations have implemented open badging successfully, and what challenges they have faced. Other research could investigate how to increase awareness and acceptance of badge credentials, the most effective scope and granularity for effective badges, how badges may or may not contribute to effective e-portfolios and overcome the challenges these portfolios have traditionally faced, how to effectively scale and manage badging systems, and how badges may contribute to enhanced motivation and self-regulation. By exploring these and other issues, we can better determine whether open badges are another technological fad, or a potentially disruptive innovation.
Application Exercises
- What are two informal learning experiences you have participated in that could be assessed with an open badge?
- Think of a skill you would like to learn. Then, look for different resources that offer badges in that skill. Compare the resources, and pick one that you would prefer to use. Explain your choice.
- The authors list several challenges to spreading the use of badges more fully. Choose one of those barriers and share some strategies you think would help address that concern.
References
Badges. (Accessed 2015, December 14). Retrieved from https://www.khanacademy.org/badges
Bowen, K., & Thomas, A. (2014). Badges: A common currency for learning. Change: The Magazine of Higher Learning, 46(March 2015), 21–25. http://doi.org/10.1080/00091383.2014.867206
Duncan, Arne. “Digital badges for learning.” MacArthur Foundation Digital Media and Lifelong Learning Competition. Hirshhorn Museum, Washington D.C. September 15, 2011. Retrieved from http://www.ed.gov/news/speeches/digital-badges-learning
Gamrat, C., & Zimmerman, H. T. (2015). An Online Badging System Supporting Educators’ STEM Learning. 2nd International Workshop for Open Badges in Education.
Gamrat, C., Zimmerman, H. T., Dudek, J., & Peck, K. (2014). Personalized workplace learning: An exploratory study on digital badging within a teacher professional development program. British Journal of Educational Technology, 45(6), 1136–1148. http://doi.org/10.1111/bjet.12200
Gibson, D., Ostashewski, N., Flintoff, K., Grant, S., & Knight, E. (2015). Digital badges in education. Education and Information Technologies, 20(2), 403–410. http://doi.org/10.1007/s10639-013-9291-7
Green, H., Facer, K., Rudd, T., Dillon, P. & Humphreys, P. (2005). Personalisation and digital technologies. Bristol: Futurelab. Retrieved February 17, 2016, from http://www.nfer.ac.uk/publications/FUTL59/FUTL59_home.cfm
Jovanovic, J., & Devedzic, V. (2014). Open badges: Challenges and opportunities. Advances in Web-Based Learning – ICWL 2014, 8613, 56–65. http://doi.org/10.1007/978-3-319-09635-3
Ma, X. (2015, April). Evaluating the implication of open badges in an open learning environment to higher education. In 2015 International Conference on Education Reform and Modern Management. Atlantis Press. Retrieved February 17, 2016, from http://www.atlantis-press.com/php/download_paper.php?id=20851
Mehta, N. B., Hull, A. L., Young, J. B., & Stoller, J. K. (2013). Just imagine. Academic Medicine, 88(10), 1418–1423. http://doi.org/10.1097/ACM.0b013e3182a36a07
Newby, T. J., Wright, C., Besser, E., & Beese, E. (2015). Passport to creating and issuing digital instructional badges. In D. Ifenthaler, N. Bellin-Mularski, & D. Mah (Eds.), Foundations of digital badges and micro-credentials: Demonstrating and recognizing knowledge and competencies. New York, NY: Springer.
O’Byrne, W. I., Schenke, K., Willis III, J. E., & Hickey, D. T. (2015). Digital badges: Recognizing, assessing, and motivating learners in and out of school contexts. Journal of Adolescent & Adult Literacy, 58(6), 451–454. http://doi.org/10.1002/jaal.381
Pink, D. H. (2011). Drive: The surprising truth about what motivates us. New York: Riverhead Books.
Randall, B. D., Harrison, J. B., & West, R. E. (2013). Giving credit where credit is due: Designing open badges for a technology integration course. TechTrends, 57(6), 88–96.
Reigeluth, C. M., & Garfinkle, R. J. (1994). Envisioning a new system of education. In C. M. Reigeluth and R. J. Garfinkle (Eds.), Systemic change in education. Englewood Cliffs, NJ: Educational Technology Publications.
Rughiniş, R., & Matei, S. (2013). Digital badges: Signposts and claims of achievement. Communications in Computer and Information Science, 374, 84–88. http://doi.org/10.1007/978-3-642-39476-8_18
University of California, Davis (2014). Sustainable agriculture & food systems (SA&FS): learner-driven badges (Working Paper). Retrieved from Reconnect Learning website: http://www.reconnectlearning.org/wp-content/uploads/2014/01/UC-Davis_case_study_final.pdf
West, R.E., Randall. D.L. (2016). The case for rigor in open badges. In L. Muilenburg & Z. Berge, (Eds.), Digital badges in education: Trends, issues, and cases (pp. 21-29). New York, NY: Routledge.
Dr. Richard E. West is an associate professor in the Department of Instructional Psychology & Technology at Brigham Young University, where he has taught since receiving his PhD in Educational Psychology and Instructional Technology from the University of Georgia. He researches social influences on creativity and innovation, online social learning, open badges and micro credentials, and K-16 technology integration. He is the co-founder of the Creativity, Innovation, and Design group at BYU http://innovation.byu.edu and co-developer of the BYU Ed Tech Badges http://badgeschool.org. His research is available on Google Scholar, Academia.edu, and richardewest.com.
Tadd Farmer is a current doctoral student in the Learning, Design, and Technology program at Purdue University. As a former middle school teacher, Tadd’s graduate research now explores how online education can provide meaningful learning experiences for students, and supportive and empowering environments for teachers. His current research projects include understanding the concerns of K-12 online teachers, investigating innovative methods for improving online student self-efficacy, and examining disciplinary differences in the design of online STEM courses. | 4,152 | common-pile/pressbooks_filtered | https://pressbooks.pub/lidtfoundations/chapter/open-badges/ | pressbooks | pressbooks-0000.json.gz:89760 | https://pressbooks.pub/lidtfoundations/chapter/open-badges/ |
3HAnBwggYs_Vgd6- | Introduction to Criminology | 6. Biological Influences on Criminal Behaviour
6.1 Genetics
Dr. Gail Anderson
It is a common misconception that the link between biology and crime is primarily genetic, yet there is much more to biology than the study of genes. However, our genes do have a profound influence on us, and a great deal of research has been conducted on the genetics of behaviour. As behaviour is highly complex, in almost all cases, any behavioural trait will be influenced by a large number of genes, not just two or three. Therefore, “a gene for crime” or for any complex behaviour cannot exist. Most behaviour is governed by thousands of genes, with each contributing a small amount towards a person exhibiting that behaviour.
Most behaviours are not criminogenic on their own, but under the right circumstances could lead to a person offending. For example, impulsivity is a behaviour that could potentially lead to a criminal event, such as not considering the consequences of stealing a car for a joy ride. Of course, impulsivity could equally result in buying way too many red shoes! How such a behaviour is enacted is greatly influenced by many other factors including socioeconomic status (SES), education, and peers. Therefore, any relationship between genes and behaviour is modulated by myriad genes and the number of genes a person has that influences that behaviour will increase their likelihood of exhibiting that behaviour.
Heritability Studies
A great deal of genetic and environmental research has been conducted using twin and adoption studies. These studies compare the impacts of genes and the environment on behaviour.
Twins are a perfect study group as there are two types of twins: monozygotic (MZ) and dizygotic (DZ). MZ (“identical”) twins began as a single zygote (one egg and one sperm) that, very shortly after fertilisation, divide into two, resulting in two genetically identical babies, aside from small early mutations that may occur (Jonsson et al., 2021). DZ twins result from two zygotes and only share 50% of their genes (actually, we share 99% of our DNA with every other human being, but of the 1% that is different between all people, siblings share 50%). DZ twins in general share 100% of their environment and 50% of their genes, whereas MZ twins, in general, share 100% of both their environment and genes. Comparing behaviours between DZ and MZ twins helps us understand whether environment or genes has a greater influence on a behavioural trait. As both types of twins share the same environment, any differences relate to genetics. A great many twin studies have been conducted globally over the last 100 years and have consistently shown both a heritable component to criminogenic behaviour and an environmental component (e.g., Anderson, 2020a; Kendler et al., 2015).
One problem with twin studies is the assumption that each set of twins share the same environment, but MZ twins, who look identical, may share more of their environment than DZ twins, who look less similar and may be different sexes. Such factors would impact the results (Burt & Simons, 2014). Adoption studies offer a much more powerful method of separating the effects of genes and the environment by comparing adopted children with their adopted and biological families. In such situations, biological parents can only contribute biological effects, and adoptive parents can only contribute environmental effects on the behaviour of adopted children, as the studies focus on children adopted by non-relatives, neatly separating biological and environmental effects. Many large studies conducted worldwide have shown that a child is much more likely to offend if their biological rather than adoptive parents were offenders, and even more likely if both are offenders (Mednick et al., 1987). These findings show both a heritable relationship and the impact of the environment.
Gene X Environment Interactions (GxE)
People with different genetic backgrounds may react differently to the same environment. We know many risk factors influence the likelihood of committing a crime—such as child abuse, low SES, and peer pressure, but most people who experience these environmental factors do not turn to crime and may be exemplary members of society. Likewise, privileged, wealthy people with supportive peers and abuse-free childhoods may still commit many crimes. We now understand that persons with certain genetic backgrounds are more sensitive to specific environmental triggers than others (Mullineaux & DiLalla, 2015). Someone without a predisposition for criminal behaviour may never offend, irrespective of an adverse environment, and a person with a predisposition for criminal behaviour may never offend if they do not experience adversity. Adversity may be any form of hardship, which includes trauma, physical, sexual or emotional abuse, starvation, or any form of severe suffering. For example, as we will discuss later, males with a certain form of a gene for a neurotransmitter or chemical messenger have a higher predisposition for aggressive behaviour only if they are severely physically abused as a child. If they are not abused, that is, they are never exposed to this trigger, they are no more likely to be aggressive than any other male (Caspi et al., 2002). A predisposition together with an adverse environment increases risk but still does not guarantee a criminal outcome because gradients in each either increase or decrease risk (Gajos et al., 2016). Several models predict these variations, such as the diathesis stress model, which suggests that a genotype has a number of different alleles or different gene variants, and each adds a tiny bit of risk (Bersted & DiLalla, 2016). If the person is exposed to a bad environment, then they are very likely to be antisocial, but if they are exposed to a good environment, they may not show any antisocial behaviour at all. So, this model predicts that the basic causes of antisocial behaviour are triggers in the environment interacting with the person’s genotype (Boardman et al., 2014). For example, it has been shown that children with certain risk factors are at greater risk of antisocial behaviour if they experience parental conflict (Feinberg et al., 2007). These findings help identify not only environmental triggers but protective factors that can ameliorate or even eliminate risk.
Epigenetics
The genome is a person’s complete set of genetic instructions or blueprint (the DNA sequence), and it is controlled by the epigenome, an array of chemicals that tell the genome which genes should be turned on (expressed) and which should be turned off. The epigenome can also change in response to experiences, altering the way a gene is expressed—that is, what the gene actually does—without changing the DNA sequence. Therefore, a person’s genome remains the same, but its functions may change in response to experiences (DeLisi & Vaughn, 2015). For example, astronauts Scott and Mark Kelly are MZ twins, but only Scott spent a year in space. See the NASA twins study revealing that space flight can cause genetic changes. Studies of their DNA before and after the space travel showed that, although their DNA remained identical, stressors experienced on the flight had changed Scott’s DNA expression (Garrett-Bakelman et al., 2019).
Interestingly, although only the expression of the genes changes and not the DNA sequence, these epigenetic changes can be passed on to the next generation, so they are heritable (National Human Genome Research Institute, 2016). This very exciting new area is only just being explored, primarily as it relates to healthcare, but some work has been done on criminogenic behaviour that helps explain GxE interactions. The epigenome is changed by the environment to allow the body to respond; changes may occur in neural development or in neurotransmitter or hormonal function, which could impact behaviour. Studies on rodents show that maternal care could result in gene expression changes in the first week of life, with increased maternal care resulting in calmer offspring that exhibit less stress to new environments than those with low maternal care (Weaver et al., 2004). When rat pups were abused for 30 minutes a day during their first week of life, the brain changes lasted a lifetime, resulting in rats that abused their own offspring (Roth & Sweatt, 2011). In both studies, the changes could be reversed with medication.
Many studies on children have shown that early life adversity and parenting decisions have an epigenetic effect on a child’s developing brain that can impact their future behaviour, mental abilities, reaction to stress, and resilience to further adversity, making them less able to cope, and such changes can be transgenerational (DeLisi & Vaughn, 2015). This is a very new understanding and means that the experiences of your parents can epigenetically affect their DNA, which will impact the way your genes and even your children’s genes will be expressed. In other words, a person’s ancestor’s experiences can genetically impact later generations. Studies show that this epigenetic effect can increase antisocial behaviour and callous unemotional aggression, reduce empathy, increase depression and reduce normal stress responses, resulting in a lack of fear of danger or consequences (DeLisi & Vaughn, 2015; Rutter, 2012).
When the communist government of Romania fell in 1989, the world was horrified to see images of hundreds of thousands of children abandoned and warehoused in appalling conditions, without the most basic necessities of life, and no human contact except abuse. This lack of basic care and human contact together with extreme deprivation and institutionalisation meant many of these children exhibited cognitive problems. What 100,000+ Children Taught Us About Neglect in Early Childhood describes some of these issues. Imaging studies showed that these children had less total grey and white matter in the brain and an enlarged amygdala—a part of the brain responsible for dealing with emotions (Mehta et al., 2009). These findings may be a result of developing epigenetic coping mechanisms and reduced responses to extreme institutionalisation. See Romania’s Abandoned Children about the impacts of institutionalisation. In other studies of abused children, epigenetic changes increased their likelihood of developing post-traumatic stress disorder in response to adversity experienced in their adult lives (Mehta et al., 2013). Kayla Bourque is a Vancouver example of a high-risk violent offender with a history of animal abuse who was adopted from a Romanian orphanage. See B.C. animal killer called ‘psychopathic’ for more on Kayla Bourque.
It has long been accepted that experiencing an abusive childhood increases risk for later offending. These studies not only show the environmental impacts of such abuse but now also a major biological impact on a child’s developing brain, making them more susceptible to later environmental triggers, potentially resulting in antisocial behaviour, an inability to deal with stressors, as well as a lack of parenting skills. Moreover, these changes can be transgenerational.
Residential Schools
Epigenetic studies help us understand why atrocities such as residential schools not only had major and long-lasting impacts on the Indigenous children who were abused, but also how the effect of this abuse is magnified as it is perpetuated biologically through the next generations, as discussed in Can Trauma Be Inherited?.
These intergenerational impacts, although considered here in a scientific context, clearly illustrate the connections between the many aspects of knowledge, including the cognitive, spiritual, emotional and physical elements, which are all parts of Indigenous epistemologies (Doetzel, 2018; Simpson, 2011; Smith, 2012). In many cases, the disruption of these interconnections has also prevented the passage of traditional, ancestral knowledge to subsequent generations (Monchalin, 2016).
Social Implications
When considering any heritable factor that impacts a physical characteristic with social implications, it must be separated from the social effect. When certain heritable characteristics such as skin colour or ancestry put a person at a social disadvantage—for example, by making them more likely to experience poverty, a lack of education, starvation or abuse—their lack of success, or increased risk, is blamed on the inherited factor. In reality, this is a social construct and a result of systemic discrimination. Possessing that heritable characteristic greatly reduced that person’s chances of success in that particular society, and it is purely the environmental disadvantages that caused the outcome, not genetics or physical differences themselves. This discrimination, rather than ancestry, in part explains the disproportionate number of Indigenous persons who are incarcerated in Canada as well as African-Americans incarcerated in the United States.
as a result of your genes, genetics – the study of heredity and genes
Deoxyribonucleic acid. A single molecule which is comprised of two polynucleotide chains which coil to form the well-known double helix. It carries all an organism’s genetic material and is formed into chromosomes.
different variants of the same gene. For example, the gene for eye colour has alleles for brown, blue, green, grey or violet eyes.
The genetic blueprint for a person, their genetic instructions.
chemical messengers in the body which act between nerve cells which produce extremely rapid responses and have a major impact on behaviour.
biological messengers that are secreted into the bloodstream by glands such as ovaries or the pancreas to communicate instructions to parts of the body for example, to release adrenalin.
something that carries on over several generations.
behaviours that hurt or harm or lack concern for other people’s welfare. Usually, it includes behaviour considered to be disruptive or aggressive. However, such a concept is a social construct in that its definition is not an actual fact but relates to human opinion. Something that is antisocial in one context may not be in another. For example, violence is almost universally considered an antisocial behaviour but not in war.
the state of being placed or kept in an institution in which life and actions are highly controlled; refers to a person developing deficits in life and social skills due to becoming used to living in an institution.
Something that exists due to human interaction. | 2,947 | common-pile/pressbooks_filtered | https://kpu.pressbooks.pub/introcrim/chapter/6-1-genetics/ | pressbooks | pressbooks-0000.json.gz:65011 | https://kpu.pressbooks.pub/introcrim/chapter/6-1-genetics/ |
dVUY3HYBYts8FZy- | 5.7: Summary Questions | 5.7: Summary Questions
5.7 Summary Questions
1. Assign a crown class to each tree illustrated below.
2. Where on this tree should the live crown be measured?
3. Determine LCR for each tree illustrated.
- The data in Table 4-4 below are from an evenaged stand in the stem exclusion stage. They represent the average live crown ratios (LCR) of trees sampled in the stand by species. Data were collected by MHCC Forest Measurements I students in February 2010.
- Do the LCR’s reflect a stand with high or low crown competition? Explain.
- Do the LCR’s of each species seem reasonable given their shade tolerance?
- These data were gathered in February. Does the time of year pose any problems for estimating LCR on deciduous species like red alder?
- Which species would you expect to dominate this stand in the future? Why?
Answers to Summary Questions
- Trees on the ends of the illustrations are hard to determine, given that we do not know what is on the other side of them. I assume there are trees beyond what is shown, so am using crown size as a partial indicator of the amount of light they are receiving. Position in the crown is key. The following are what I would assign, but I think the starred one (*) is borderline, and could be assigned the next higher crown class.
- Since LCR is simply a ratio, any scale can be used to measure. I used the 20 scale on my triangular engineer’s ruler to obtain fairly good precision. So your values may differ, but LCR% should be similar.
Trees with slope measurements from left to right:
Tree 1: (70-14) = 70% Tree 2: (70-38) = 40% Tree 3: (70-22) = 60%
(70+10) (70+10) (70+10)
- The following answers refer to the data presented in Table 4-4.
- The bulk of the trees in this stand are Douglas-fir, with an average live crown ratio of 40%. This indicates to me a canopy experiencing high crown competition. As crown closure occurs, trees drop low branches that are being shaded (particularly shade intolerant or intermediate species like red alder and Douglas-fir). Foresters often refer to a lower limit of 30% LCR as their cut-off for vigorously growing trees. If I were managing this stand, I would seriously consider a thinning to increase light availability to the trees I wanted to maintain on the site.
- We would expect the live crown ratios to be the shortest on the shade intolerant species, and longest on the shade tolerant. Our measurements show this pattern; red alder<Douglas-fir<western hemlock. However, since only one western redcedar was measured, we don’t have a representative sample for this species.
- These trees were measured in the winter, with no leaves, and only buds to indicate where the bottom of the crown was. I would take the red alder LCR estimates with a grain of salt.
- I would expect Douglas-fir to continue to dominate in the future, followed by western hemlock. Red alder is a short-lived species, and is already subordinate in the forest. | 670 | common-pile/libretexts_filtered | https://bio.libretexts.org/Bookshelves/Botany/Forest_Measurements_-_An_Applied_Approach_(DeYoung)/05%3A_Stand_Characteristics/05.7%3A_Summary_Questions | libretexts | libretexts-0000.json.gz:41413 | https://bio.libretexts.org/Bookshelves/Botany/Forest_Measurements_-_An_Applied_Approach_(DeYoung)/05%3A_Stand_Characteristics/05.7%3A_Summary_Questions |
4GFh_n-K5fputQVJ | 3.1.8: Personality Theory in Real Life- ...and in Death! | 3.1.8: Personality Theory in Real Life- ...and in Death!
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Arthur Benjamin Niemoller was a fine example of a man who had achieved integrity in old age, which is not to say that his later years were entirely easy. As he prepared to travel from Ohio to Massachusetts for the first graduation of one of his grandchildren from college (me), his wife lapsed into a coma due to a serious blood infection. Knowing it was unlikely that she would survive, or that she would even know if he was there, he chose to attend my graduation. After the ceremony was over, and everyone returned to my mother’s house for a party, the call had come from the doctor. My grandmother had died. I spent the next week in Ohio, helping my grandfather make the funeral arrangements for my grandmother. We had a service in Montgomery, Ohio where they had lived for many years, and then another in Putnam, Connecticut, where there is an old family graveyard. My grandfather made it very clear that he was glad he had attended my graduation, because he was proud of his family and wouldn’t have wanted to miss it.
Figure \(\PageIndex{1}\)
Arthur Benjamin Niemoller (1912-1998) lived a long and full life.
But the story doesn’t end there. I attended graduate school at Wayne State University in Detroit, which isn’t too far from the Cincinnati area, where Montgomery is located. I began visiting my grandfather regularly, which was quite interesting because I’d had very little contact with him before that (my family has never been close). He was a very active man. He was a Sunday school teacher and church council member at the local Presbyterian church, he belonged to a retired men’s club, he had season tickets to the opera, and he regularly attended the symphony. He had many friends, some of whom had also lost their spouses to old age. Most surprising, however, was that in his late 70s he joined two other men in forming a new company. He was responsible for developing the computer programs that calculated the materials needed and the cost of those materials for building an isolated phase bus (something for carrying industrial strength electrical currents in power plants, I never really understood what he did). He was very proud of his work, and always eager to show me his new computer programs. We developed a relationship I will always treasure.
The last time I saw my grandfather, he had been given 3 weeks to live. He had been suffering from dementia for several years, and typically wasn’t sure who was visiting him. He thought I was his son Donny, and it didn’t help that my wife and my aunt are both named Donna. On that last day I saw him, he was not the excited man of 80 years old who had a new computer program to show me. In fact, it took a while for me to convince myself he was actually still alive. It is frightening to see what can happen to the human body as a result of what is simply a natural process (old age, that is, dementia is certainly not a given with old age). Before I left, I prayed to God, deeply and sincerely, that my grandfather would finally just die. I was the last person in our family to see him alive. It is even more frightening, though merciful nonetheless, to think that my prayer was answered. I was satisfied that his life had been a good one, and content that his suffering was ended.
Has there been anyone in your life who meant a great deal to you but who has died? Were you able to participate in their dying process, and if so, how difficult was it? Imagine what it might be like to face death yourself, and think about how you might want others to treat you. Do your feelings and expectations fit within the cultural expectations and/or traditions of your family and community? | 876 | common-pile/libretexts_filtered | https://socialsci.libretexts.org/Courses/Clinton_College/Psychology_of_Religion_-_Perspectives_and_Cultures_(McCullers)/03%3A_Erikson_and_Considerations_for_the_Stages_of_Life/3.01%3A_Erik_Erikson/3.1.08%3A_Personality_Theory_in_Real_Life-_...and_in_Death | libretexts | libretexts-0000.json.gz:4199 | https://socialsci.libretexts.org/Courses/Clinton_College/Psychology_of_Religion_-_Perspectives_and_Cultures_(McCullers)/03%3A_Erikson_and_Considerations_for_the_Stages_of_Life/3.01%3A_Erik_Erikson/3.1.08%3A_Personality_Theory_in_Real_Life-_...and_in_Death |
75F_MPA0wfmR3RAA | Atwater, Minnesota: 1934-1935 | 87 P.T.A. committee meets at the Broman coffee shop
February 17, 1935
Dear Corinna,
Sunday P.M. H and G are cutting out paper dolls—Daddy snoring on the Davenport—Myron practicing at the M.E. Church with Miss Steen. This morning at S.S. I taught them all, the song Edwin McHugh sings. I picked it out on the piano last night—I start it on C—and play it in the key of F. Phyllis Swenson asked me to write it off for her so she could play it so I have done that since dinner. I made it into 4/4 time and started it on the 4th beat. It’s pretty low but that’s the way I like to sing it. First I play the simple air—then I go down an octave and cross my hands like Tillie and then I play it higher in octaves. It makes an effective offertory for a short one and I think I’ll use it tonight. Everyone at S.S. liked both words and the tune.
Friday eve, Gladers took Myron, H and G and me to Willmar to hear an Italian singer—Mario Capelli—tenor. It was in the M.E. Church—he sang part of operas—children’s songs—hymns—all kinds—even “Wagon Wheels”. He is the best I’ve ever heard—gave a talk on “Ship-wreck”, also. He advised every one to stay on the right course—to avoid ship-wrecked lives.
Yesterday the P.T.A. committee met at the Broman coffee shop to plan our eats for next Wed. eve. Mrs. Swenson is chairman—Mrs. Melin, Betty, Bessie, Mrs. Ed Miller and I are the hostesses. We are going to have sponge cake and whipped cream with a cherry on top. Betty and I have charge of table decorations so we borrowed Katherine Strong figures she made of Geo and his stern father and the chopped down cherry tree. Herbert lent us two handsome figures of Uncle Sam to have at each end of the table also. Then we will put a narrow strip of red and blue crepe paper along the edge of the tablecloth. The speaker is to be Mr. Utne of the State Board of Education on Tax Revision of State Aid to schools. We have just been reading that in the League and I certainly hope I can hear him. Suppose we’ll have to be beating cream about that time.
Yes, I mean a congoleum rug for the dining room. They don’t even have new catalogs down here at Lundgrens so I can’t even pick it out yet. I wish I could get to Mpls. and pick something out for myself once.
Winnie is back again. She stopped in after church this noon. Byron’s job at the Gas plant is over but he will work for a few weeks at changing the meters for the city. I could tell from her attitude that both she and Byron feel out of sorts with the world. It’s too bad but what they need is more preparation and concentration and sacrifice. Where’s Russy now in his book? Music, I mean.
Now everybody has cleared out and I am alone in the house. Will try to catch up in my Reading a little. Dorothy Brown is to marry Burton (not Bernard) Thorpe this week. Do you know him? Love from Mother. | 703 | common-pile/pressbooks_filtered | https://mlpp.pressbooks.pub/atwater1934/chapter/chapter-87/ | pressbooks | pressbooks-0000.json.gz:59191 | https://mlpp.pressbooks.pub/atwater1934/chapter/chapter-87/ |
wQA0zJxR-_uYfIJy | Community and Public Health Nursing Instructor Guide | Chapter Nine: Trauma-Informed Care
Practical Application: Book Activity
Practical Application
Setting the Scene
Stressful time often denotes being bombarded with many things at one time, perceived or actual, without sufficient time or ability to address them emotionally, cognitively, spiritually, and/or physically. The same goes for trauma — rapid exposure to numerous traumas one after another lessens one’s ability to process the event before the next onslaught. This creates a cumulative effect, making it more difficult to heal from any singular trauma.
Think About It
Imagine an event that was particularly stressful (but not traumatic) in your life. Revisit this period as an observer watching the events unfold.
- What made this event particularly stressful? Was it difficult to manage one situation before another circumstance came along demanding your time?
- How did you process the event? What were the resources you used? Did you learn anything from processing it?
- Are there any tools you’d use to process similar situations moving forward?
- Suppose in your work area you were exposed to multiple poor patient outcomes over several days.
- How do you think this situation might impact you and your role as a nurse?
- Would you be able to use some of these same resources that you used to process your stressful event? Why or why not?
Practical Application: Additional Guidance
Exercise Title
Reflecting on Stressful Events and Building Resilience Application Practice
Objectives
- Understanding Stress and Trauma:
- Explore the impact of cumulative stress and rapid exposure to trauma.
- Recognize the challenges of healing from singular traumatic events.
- Personal Reflection:
- Identify coping strategies and resources used during a stressful time.
- Professional Application:
- Apply personal insights to the nursing role.
- Consider resilience-building tools for managing work-related stress.
Preparing for the Exercise
- Setting the Scene:
- Discuss the concept of cumulative stress and its parallels with trauma.
- Emphasize the importance of processing events effectively.
- Reflective Practice:
- Encourage students to choose a specific stressful event from their lives.
- Remind them to observe the events as an objective observer.
Exercise Components
- Personal Reflection (30 minutes):
- Answer the following questions:
- What made the chosen event particularly stressful?
- Was it challenging to manage multiple situations demanding your attention?
- How did you process the event? What coping mechanisms or resources did you use?
- Did you learn anything from this experience?
- Answer the following questions:
- Workplace Scenario (45 minutes):
- Imagine exposure to multiple poor patient outcomes over several days.
- Discuss potential impacts on your well-being and nursing role.
- Consider whether the same coping resources would apply in this professional context.\
- Resilience-Building Discussion (20 minutes):
- Explore tools for resilience:
- Self-Care: Prioritize physical, emotional, and spiritual well-being.
- Support Networks: Connect with colleagues, mentors, and friends.
- Mindfulness Practices: Ground yourself in the present moment.
- Professional Boundaries: Set limits to prevent emotional overload.
- Explore tools for resilience:
Evaluation and Assessment
- Assess students’ reflections, depth of insight, and ability to apply personal experiences to professional contexts.
Integration into Curriculum
- Alignment with Course Objectives: Integrate trauma-informed care principles into nursing courses.
- Sequencing: Determine the appropriate timing and sequencing of the exercise within the course curriculum to complement other content and activities.
- Integration of Theory and Practice:
- Include case studies related to stress management and resilience.
Resources and Support
- Learning Resources: Provide students with access to relevant literature, articles, and resources on epidemiology or disaster nursing, including:
- Student Support: Share school/University resources for mental health support groups and counseling.
- Faculty Support: Offer guidance, feedback, and support to students as they engage in the exercise, addressing any questions or concerns they may have about the scenario or related topics.
Conclusion
By reflecting on personal stressors and considering resilience-building strategies, nurses enhance their ability to provide trauma-informed care and maintain well-being in challenging environments. Remember to customize this activity to the needs of your students.
Additional Activities
Role-playing/Communication Exercise
Scenario Title
Trauma-Informed Care
Objective
To enhance nursing students’ understanding and application of trauma-informed care principles when interacting with patients who have experienced trauma. It focuses on fostering empathy, building trust, and creating a safe environment for healing.
A patient arrives with injuries from a car accident. The patient appears distressed and avoids eye contact. You suspect the patient may have experienced trauma related to the accident.
Communication Activity
- Pre-Exercise Preparation
- Brief participants on trauma-informed care principles and the importance of creating a safe and supportive environment for patients who have experienced trauma.
- Review Trauma-Informed Care Principles:
- Safety
- Trustworthiness and transparency
- Peer support
- Collaboration and mutuality
- Empowerment, voice, and choice
- Cultural, historical, and gender issues
- Discuss Communication Strategies:
- Use of non-judgmental language
- Active listening skills
- Respect for patient autonomy
- Recognizing triggers and managing emotions
- Scenario Introduction
- Introduce the scenario to participants and assign roles. Provide background information about the patient’s potential trauma history related to the car accident.
- Scenario Description:
- The patient arrives in the emergency department with visible injuries and signs of distress.
- The nurse’s role is to provide compassionate care while applying trauma-informed communication techniques.
- Role-Play Interaction
- Participants engage in a role-play interaction where the nurse applies trauma-informed communication strategies to assess and provide care for the patient.
- Role-Play Guidelines:
- Nurse focuses on building rapport and establishing trust with the patient.
- Nurse demonstrates empathy and validates the patient’s feelings and experiences.
- Nurse uses open-ended questions and active listening to gather information sensitively.
- Nurse respects the patient’s boundaries and autonomy throughout the interaction.
Debriefing and Feedback
After the role-play, conduct a debriefing session where each participant reflects on their experience, provides feedback, and discusses lessons learned.
Debriefing Questions:
- How did you approach the patient to build trust and establish safety?
- What communication techniques did you find effective in this scenario?
- Were there any challenges in applying trauma-informed care principles? How did you address them?
- How did the patient respond to your communication approach?
Feedback:
- Participants provide feedback to each other based on observed communication skills, empathy, and adherence to trauma-informed care principles.
- Facilitator offers guidance and additional insights on effective communication strategies in trauma-informed care.
Reflective Practice
This activity could occur on a discussion board or by uploading a video using Flip or Canvas Studio.
How can nurses consistently incorporate trauma-informed care principles to promote patient-centered healing and recovery?
Interactive Module
Create an interactive escape room using Google Forms that challenges students to solve puzzles related to the chapter topic. These NCLEX-style questions can be a starting point.
- Which action best demonstrates trauma-informed care by a nurse?
- Providing detailed explanations without considering the patient’s readiness to receive information.
- Using open-ended questions to explore the patient’s feelings and preferences.
- Directing the patient’s decision-making process to expedite treatment.
- Minimizing patient autonomy to ensure compliance with treatment plans.
- A nurse is caring for a patient with a history of trauma. Which intervention is most appropriate to promote a trauma-informed approach?
- Engaging the patient in shared decision-making regarding their care plan.
- Implementing restrictive measures to prevent potential harm to the patient.
- Limiting communication to essential medical information only.
- Encouraging the patient to conform to hospital routines without discussion.
- Which statement by the nurse best demonstrates trauma-informed communication?
- “I need to perform this procedure now, so please cooperate.”
- “Can you tell me if there’s anything specific that makes you feel more comfortable during medical exams?”
- “You seem upset, but we don’t have time to discuss your feelings right now.”
- “I know what’s best for you, so please trust my judgment.”
- A nurse is caring for a patient who becomes agitated during a procedure due to past trauma. Which action by the nurse demonstrates trauma-informed care?
- Administering sedative medication without discussing options with the patient.
- Ignoring the patient’s distress to focus on completing the procedure efficiently.
- Restraining the patient to ensure safety and prevent disruptive behavior.
- Asking the patient about their past experiences and triggers to better understand their reaction.
- What is the primary goal of trauma-informed care in nursing practice?
- Minimizing patient involvement in decision-making to reduce stress.
- Applying rigid protocols to ensure consistent treatment outcomes.
- Creating a safe and supportive environment for patients with trauma histories.
- Promoting healthcare provider convenience by streamlining patient care processes.
Case Study: Delivering Trauma-Informed Care
Background
Owen is a 35-year-old man who was admitted to the hospital after a motor vehicle accident. He sustained multiple fractures and internal injuries. During the initial assessment, Owen appears withdrawn, avoids eye contact, and exhibits signs of anxiety when approached by healthcare providers. He discloses a history of childhood abuse and recent domestic violence.
Scenario
Clinical Presentation
Owen is in significant pain but hesitates to accept pain medication. He expresses fear about being touched and feels unsafe in the hospital environment. Owen’s vital signs are stable, but he exhibits signs of emotional distress and hypervigilance.
Nursing Assessment and Intervention
The nurse recognizes Owen’s signs of trauma and decides to implement trauma-informed care principles:
- Building Trust and Safety:
- The nurse introduces themselves calmly and explains his role in Owen’s care.
- Uses non-threatening body language and maintains a respectful distance, respecting Owen’s personal space.
- Empowering Patient Autonomy:
- The nurse explains Owen’s treatment options, including pain management strategies, and encourages him to make decisions about his care.
- Offers choices when possible, such as adjusting bed positioning or selecting comfort measures.
- Sensitive Communication:
- Engages in open-ended conversations to understand Owen’s concerns and preferences.
- Validates Owen’s emotions and assures his that his feelings are understood and respected.
- Safety Planning:
- Collaborates with the healthcare team to create a plan for minimizing triggers and ensuring a safe environment for Owen.
- Implements strategies to reduce noise and limit unnecessary interruptions to promote a calm atmosphere.
- Trauma-Informed Documentation:
- Records information in a factual and non-judgmental manner, focusing on Owen’s responses to interventions and any observed triggers or concerns.
Outcome
Through consistent application of trauma-informed care principles, Owen gradually begins to trust the nursing team. He becomes more receptive to pain management interventions and actively participates in discussions about his treatment plan. Owen’s anxiety levels decrease, and he demonstrates improved coping strategies during his hospitalization.
Questions for Reflection and Analysis
- What steps can you take to ensure Owen or similar patients feel comfortable with their nursing team?
- What types of body language might make Owen uncomfortable? Feel safe?
- Why is it important to offer choices to patients, especially those with trauma?
Simulation
Scenario
Trauma-Informed Care in a Community Outreach Program
Objective
To enhance nursing students’ understanding and application of trauma-informed care principles when interacting with individuals in a community setting who have experienced trauma. Nursing students will practice communication skills, empathy, and creating a supportive environment to facilitate healing and trust outside of traditional healthcare settings.
Setting
A community health center or outreach location, with simulated community members and interactive props.
Roles
- Nurse (Primary role)
- Community Member (Role-played by a student or a standardized patient)
- Observer
Materials Needed
- Scenario briefing cards
- Trauma-informed care guidelines
- Simulation equipment (basic medical supplies, community health education materials)
- Feedback forms
Simulation Outline
- Pre-Simulation Briefing
- Introduce trauma-informed care principles, review scenario details, and assign roles.
- Review Trauma-Informed Care Principles:
- Safety
- Trustworthiness and transparency
- Peer support
- Collaboration and mutuality
- Empowerment, voice, and choice
- Cultural, historical, and gender issues
- Discuss Simulation Objectives:
- Emphasize the importance of empathy, cultural sensitivity, and creating a safe environment for community members who have experienced trauma.
- Simulation Introduction
- Introduce the simulation scenario to participants and set expectations.
- Scenario Description:
- The community member (role-played or standardized) seeks assistance at a community health outreach event due to past trauma experiences, including domestic violence.
- They are hesitant to engage with healthcare providers and may exhibit signs of distress or anxiety.
- The nurse’s role is to provide trauma-informed care while offering support and resources to meet the community member’s needs.
- Role-Play Interaction
- Participants engage in the role-play interaction, applying trauma-informed care principles to assess and provide support for the community member.
- Key Actions for the Nurse:
- Approach the community member with respect and cultural sensitivity, acknowledging their experiences.
- Use non-judgmental language and active listening skills to understand the community member’s concerns and preferences.
- Collaborate with the community member to identify their needs and goals for support.
- Provide information on available community resources and empower the community member to make informed decisions about their health and well-being.
Debriefing and Feedback
After the simulation, conduct a debriefing session where each participant reflects on their experience, provides feedback, and discusses lessons learned.
Debriefing Questions
- How did you establish trust and safety with the community member during the simulation?
- What communication techniques were effective in promoting a trauma-informed approach in a community setting?
- Were there any cultural considerations or challenges in applying trauma-informed care principles? How did you address them?
- How did the community member respond to your approach? What improvements could be made?
Feedback:
- Participants provide feedback to each other based on observed communication skills, empathy, and adherence to trauma-informed care principles.
- Facilitator offers guidance and additional insights on effective communication strategies in trauma-informed care within diverse community settings.
Competency Assessment
Demonstration
- Conduct literature reviews on trauma-informed care practices, exploring current research, guidelines, and innovative approaches in nursing and healthcare.
- Initiate or participate in quality improvement projects within clinical settings to enhance trauma-informed care delivery and patient outcomes.
- Engage in community-based projects focused on raising awareness about trauma-informed care principles and promoting resilience within communities.
Clinical Activities/Opportunities
- Substance Use Clinics/Programs: Participate in clinical experiences in programs that support individuals recovering from substance use disorder, many of whom have experienced trauma.
- Postpartum Support: Participate in postpartum care and support services that address the emotional and psychological needs of new parents who have experienced trauma.
- Rehabilitation Services: Learn about trauma-informed approaches to rehabilitation and recovery for patients recovering from injuries or surgeries related to trauma. | 3,133 | common-pile/pressbooks_filtered | https://viva.pressbooks.pub/cphnursing-instructor/chapter/chapter-9/ | pressbooks | pressbooks-0000.json.gz:18823 | https://viva.pressbooks.pub/cphnursing-instructor/chapter/chapter-9/ |
K1_4t70Dbmt3GqDz | 21.8: Exercises | 21.8: Exercises
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Write the chemical formula and Lewis structure of the following, each of which contains five carbon atoms:
- an alkane
- an alkene
- an alkyne
What is the difference between the hybridization of carbon atoms’ valence orbitals in saturated and unsaturated hydrocarbons?
On a microscopic level, how does the reaction of bromine with a saturated hydrocarbon differ from its reaction with an unsaturated hydrocarbon? How are they similar?
On a microscopic level, how does the reaction of bromine with an alkene differ from its reaction with an alkyne? How are they similar?
Explain why unbranched alkenes can form geometric isomers while unbranched alkanes cannot. Does this explanation involve the macroscopic domain or the microscopic domain?
Explain why these two molecules are not isomers:
Explain why these two molecules are not isomers:
How does the carbon-atom hybridization change when polyethylene is prepared from ethylene?
Write the Lewis structure and molecular formula for each of the following hydrocarbons:
- (f) 4-methyl-2-pentyne
Write the chemical formula, condensed formula, and Lewis structure for each of the following hydrocarbons:
- (f) 3,4-dimethyl-1-pentyne
Give the complete IUPAC name for each of the following compounds:
-
(c)
(d)
(e)
(f)
(g)
Give the complete IUPAC name for each of the following compounds:
-
(c)
(d)
(e)
(f)
Butane is used as a fuel in disposable lighters. Write the Lewis structure for each isomer of butane.
Write Lewis structures and name the five structural isomers of hexane.
Write Lewis structures for the cis–trans isomers of
Write structures for the three isomers of the aromatic hydrocarbon xylene, C 6 H 4 (CH 3 ) 2 .
Isooctane is the common name of the isomer of C 8 H 18 used as the standard of 100 for the gasoline octane rating:
- What is the IUPAC name for the compound?
- Name the other isomers that contain a five-carbon chain with three methyl substituents.
Write Lewis structures and IUPAC names for the alkyne isomers of C 4 H 6 .
Write Lewis structures and IUPAC names for all isomers of C 4 H 9 Cl.
Name and write the structures of all isomers of the propyl and butyl alkyl groups.
Write the structures for all the isomers of the –C 5 H 11 alkyl group.
Write Lewis structures and describe the molecular geometry at each carbon atom in the following compounds:
- cis -3-hexene
- cis -1-chloro-2-bromoethene
- 2-pentyne
- trans - 6 -ethyl-7-methyl-2-octene
Benzene is one of the compounds used as an octane enhancer in unleaded gasoline. It is manufactured by the catalytic conversion of acetylene to benzene:
Draw Lewis structures for these compounds, with resonance structures as appropriate, and determine the hybridization of the carbon atoms in each.
Teflon is prepared by the polymerization of tetrafluoroethylene. Write the equation that describes the polymerization using Lewis symbols.
Write two complete, balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
- 1 mol of 1-butyne reacts with 2 mol of iodine.
- Pentane is burned in air.
Write two complete, balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
- 2-butene reacts with chlorine.
- benzene burns in air.
What mass of 2-bromopropane could be prepared from 25.5 g of propene? Assume a 100% yield of product.
Acetylene is a very weak acid; however, it will react with moist silver(I) oxide and form water and a compound composed of silver and carbon. Addition of a solution of HCl to a 0.2352-g sample of the compound of silver and carbon produced acetylene and 0.2822 g of AgCl.
- What is the empirical formula of the compound of silver and carbon?
- The production of acetylene on addition of HCl to the compound of silver and carbon suggests that the carbon is present as the acetylide ion, . Write the formula of the compound showing the acetylide ion.
Ethylene can be produced by the pyrolysis of ethane:
How many kilograms of ethylene is produced by the pyrolysis of 1.000 10 3 kg of ethane, assuming a 100.0% yield?
Why do the compounds hexane, hexanol, and hexene have such similar names?
Write condensed formulas and provide IUPAC names for the following compounds:
- ethyl alcohol (in beverages)
- methyl alcohol (used as a solvent, for example, in shellac)
- ethylene glycol (antifreeze)
- isopropyl alcohol (used in rubbing alcohol)
- glycerine
Give the complete IUPAC name for each of the following compounds:
(a)
(b)
(c)
Give the complete IUPAC name and the common name for each of the following compounds:
(a)
(b)
(c)
Write the condensed structures of both isomers with the formula C 2 H 6 O. Label the functional group of each isomer.
Write the condensed structures of all isomers with the formula C 2 H 6 O 2 . Label the functional group (or groups) of each isomer.
Draw the condensed formulas for each of the following compounds:
- dipropyl ether
- 2,2-dimethyl-3-hexanol
- 2-ethoxybutane
MTBE, Methyl tert -butyl ether, CH 3 OC(CH 3 ) 3 , is used as an oxygen source in oxygenated gasolines. MTBE is manufactured by reacting 2-methylpropene with methanol.
- Using Lewis structures, write the chemical equation representing the reaction.
- What volume of methanol, density 0.7915 g/mL, is required to produce exactly 1000 kg of MTBE, assuming a 100% yield?
Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
- propanol is converted to dipropyl ether
- propene is treated with water in dilute acid.
Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
- 2-butene is treated with water in dilute acid
- ethanol is dehydrated to yield ethene
Order the following molecules from least to most oxidized, based on the marked carbon atom:
Predict the products of oxidizing the molecules shown in this problem. In each case, identify the product that will result from the minimal increase in oxidation state for the highlighted carbon atom:
(a)
(b)
(c)
Predict the products of reducing the following molecules. In each case, identify the product that will result from the minimal decrease in oxidation state for the highlighted carbon atom:
(a)
(b)
(c)
Explain why it is not possible to prepare a ketone that contains only two carbon atoms.
How does hybridization of the substituted carbon atom change when an alcohol is converted into an aldehyde? An aldehyde to a carboxylic acid?
Fatty acids are carboxylic acids that have long hydrocarbon chains attached to a carboxylate group. How does a saturated fatty acid differ from an unsaturated fatty acid? How are they similar?
Write a condensed structural formula, such as CH 3 CH 3 , and describe the molecular geometry at each carbon atom.
- (f) formaldehyde
Write a condensed structural formula, such as CH 3 CH 3 , and describe the molecular geometry at each carbon atom.
- 2-propanol
- acetone
- dimethyl ether
- acetic acid
- 3-methyl-1-hexene
The foul odor of rancid butter is caused by butyric acid, CH 3 CH 2 CH 2 CO 2 H.
- Draw the Lewis structure and determine the oxidation number and hybridization for each carbon atom in the molecule.
- The esters formed from butyric acid are pleasant-smelling compounds found in fruits and used in perfumes. Draw the Lewis structure for the ester formed from the reaction of butyric acid with 2-propanol.
Write the two-resonance structures for the acetate ion.
Write two complete, balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures:
- ethanol reacts with propionic acid
- benzoic acid, C 6 H 5 CO 2 H, is added to a solution of sodium hydroxide
Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
- 1-butanol reacts with acetic acid
- propionic acid is poured onto solid calcium carbonate
Yields in organic reactions are sometimes low. What is the percent yield of a process that produces 13.0 g of ethyl acetate from 10.0 g of CH 3 CO 2 H?
Alcohols A, B, and C all have the composition C 4 H 10 O. Molecules of alcohol A contain a branched carbon chain and can be oxidized to an aldehyde; molecules of alcohol B contain a linear carbon chain and can be oxidized to a ketone; and molecules of alcohol C can be oxidized to neither an aldehyde nor a ketone. Write the Lewis structures of these molecules.
Write the Lewis structures of both isomers with the formula C 2 H 7 N.
What is the molecular structure about the nitrogen atom in trimethyl amine and in the trimethyl ammonium ion, (CH 3 ) 3 NH + ? What is the hybridization of the nitrogen atom in trimethyl amine and in the trimethyl ammonium ion?
Write the two resonance structures for the pyridinium ion, C 5 H 5 NH + .
Draw Lewis structures for pyridine and its conjugate acid, the pyridinium ion, C 5 H 5 NH + . What are the hybridizations, electron domain geometries, and molecular geometries about the nitrogen atoms in pyridine and in the pyridinium ion?
Write the Lewis structures of all isomers with the formula C 3 H 7 ON that contain an amide linkage.
Write two complete balanced equations for the following reaction, one using condensed formulas and one using Lewis structures.
Methyl amine is added to a solution of HCl.
Write two complete, balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.
Ethylammonium chloride is added to a solution of sodium hydroxide.
Identify any carbon atoms that change hybridization and the change in hybridization during the reactions in Exercise 20.26.
Identify any carbon atoms that change hybridization and the change in hybridization during the reactions in Exercise 20.39.
Identify any carbon atoms that change hybridization and the change in hybridization during the reactions in Exercise 20.51. | 2,191 | common-pile/libretexts_filtered | https://chem.libretexts.org/Bookshelves/General_Chemistry/Chemistry_-_Atoms_First_2e_(OpenStax)/21%3A_Organic_Chemistry/21.08%3A_Exercises | libretexts | libretexts-0000.json.gz:3799 | https://chem.libretexts.org/Bookshelves/General_Chemistry/Chemistry_-_Atoms_First_2e_(OpenStax)/21%3A_Organic_Chemistry/21.08%3A_Exercises |
mbJBOHcTWfiEoSE1 | 4.2: Bollywoodization, Immaterial Labor, and Mass Creativity | 4.2: Bollywoodization, Immaterial Labor, and Mass Creativity
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- Shanti Kumar
- University of California Press
The term Bollywood was coined in the 1970s to capture—often pejoratively—the similarities between India’s national Hindi film industry based in Bombay (now Mumbai) and the globally dominant Hollywood film industry in the United States. However, as Ashish Rajadhyaksha argues, Bollywood in recent times has been used not just to describe Hindi films produced in Bombay but also to refer to “a more diffuse cultural conglomeration involving a range of distribution and consumption activities from websites to music cassettes, from cable to radio.” 3 Therefore, Rajadhyaksha uses the term Bollywoodization to signify a very recent phenomenon in Indian cinema that has emerged since the 1990s as a result of the “synchronous developments of international capital and diasporic nationalism.” 4
In the dominant “national” model of Indian cinema, the relationship between production and consumption has always been clearly demarcated, dividing those who make films (directors, producers, writers, actors, and other crew members or below-the-line workers) from those who watch films (moviegoers, fans, and consumers of film-based media, memorabilia, and culture). As Derek Bose argues in Brand Bollywood , when hundreds of formulaic Hindi films are being mass-produced in Bombay, the process of filmmaking often resembles the assembly-line mode of industrial production on a factory floor. 5 Recounting a time in the 1990s when industry output had reached over 900 films per year and over 14,000 titles were registered with the Indian Motion Pictures Producers Association (IMPPA), Bose writes, “Actors like Govinda and Anil Kapoor were doing as many as five shifts a day and Mahesh Bhatt acquired the distinction of being India’s first ‘director by remote control.’ At any given time, he had three or four projects on the floor and he would sit at home, instructing various assistants on telephone to can his shots. Films were thus directed by proxy, in keeping with the best traditions of assembly-line production.” 6
Many of these films were major box office hits because the assembly-line mode of mass production was sustained by a national network of financier-distributors whose monopoly over clearly demarcated distribution territories could ensure that mass audiences would always throng into theaters to watch their favorite movie stars on the big screen. The fairly standardized model of formulaic filmmaking and the national system of financing and distribution did not allow for—or did not require—much input from the mass audiences in relations of production. In an industry driven by what Tejaswini Ganti calls “the ratio of hits to flops,” filmmakers considered the commercial success or failure of films “as an accurate barometer of social attitudes, norms, and sensibilities, thus providing the basis for knowledge about audiences.” 7 Of course, the failure—or the fear of failure—of big-budget, big-star films was always a good reason for producers to incorporate audience feedback into the production process. But the creative power of the mass audiences to reframe cinematic narratives or to reshape filmmaking practices was limited in the national model of mass production, mass distribution and mass consumption in Indian cinema.
However, with the Bollywoodization of Indian cinema since the late 1990s and early 2000s, a more diffused, global model of cultural production has emerged where the relationship between film producers and consumers has, of necessity, become less hierarchical and more transversal. The changes in creative and industrial practices produced by the Bollywoodization of Indian cinema have been deftly analyzed by Aswin Punathambekar in From Bombay to Bollywood: The Making of a Global Media Industry . Contrasting the new Bollywoodized mode of production with the traditional model of filmmaking in Indian cinema, Punathambekar argues that the “ongoing changes in the domain of marketing and promotions are emblematic of broader reconfigurations of relations between capital, circuits of information and forms of knowledge . . . in Bombay’s media world.” 8 For instance, discussing the growing centrality of paratexts such as trailers, posters, music videos of song and dance sequences, and media events such as the mahurat (ritual inauguration of a new production) and promotional tours by film stars and singers, Punathambekar examines how marketing and promotion have become new sites of decision making, communication, and knowledge about the film commodity even before a film is released or produced.
Since the paratexts and media events discussed by Punathambekar are not traditionally considered integral parts of the filmmaking process or the film commodity, the labor involved in their production (including advertising, marketing, promotion, spot films, web sites, online chat sessions with fans, and games and contests for mobile devices) is what Lazzarato would define as immaterial labor. To recall Lazzarato’s definition outlined earlier, immaterial labor consists of two types of work in the capitalist production of a commodity (such as a film): informational labor (such as the use of digital technologies, paratexts, media events, marketing, and promotion materials before, during, and after production) and cultural labor (the production of affective value through the circulation of the film commodity in social life—such the pleasures of producing and consuming the texts and paratexts of a film, the thrill of participating in media events, the social bonds of sharing and recommending “free” marketing and promotional materials about the film to online and offline friends, and so on). Taken together, the two types of immaterial labor—informational and cultural—produce affective value for the film commodity in all aspects of social life.
The affect of immaterial labor is, of course, difficult to track. As Thrift points out, there are many definitions of affect, and they are often “associated with words like emotion and feeling, and a consequent repertoire of terms like hatred, shame, envy, fear, disgust, anger, embarrassment, sorrow, grief, anguish, love, happiness, joy, hope, wonder.” 9 However, Thrift finds that these words are not good translations of affect and therefore proposes to move away from definitions that focus on individualized emotions. Instead, Thrift favors approaches that define affect in terms of general tendencies and lines of forces. Of these approaches, Thrift highlights four: affect as embodied knowledge, affect theory associated with but differentiated from psychoanalytic conceptions of libidinal drives, the Spinozian-Deleuzian notion of affect as emergent capacities, and neo-Darwinian frameworks of affect as a universal expression of emotion. Summarizing his extensive review of the literature on these four approaches to affect, Thrift writes, “Four different notions of affect, then. Each of them depends on a sense of push in the world but the sense of push is subtly different in each case. In the case of embodied knowledge, that push is provided by the expressive armoury of the human body. In the case of affect theory it is provided by biologically differentiated positive and negative affects rather than the drives of Freudian theory. In the world of Spinoza and Deleuze, affect is the capacity of interaction that is akin to a natural force of emergence. In the neo-Darwinian universe, affect is a deep-seated physiological change involuntarily written on the face.” 10
Although affect—as general tendencies and lines of force—is a widespread and crucial element of urban life, Thrift argues that the affective register has been largely neglected in the study of cities. Defining urban life through the concept of “affective cities,” Thrift argues that affects like anger, fear, joy, and hope manifest themselves in “the mundane emotional labor of the workplace, the frustrated shouts and gestures of road rage, the delighted laughter of children as they tour a theme park or the tears of a suspected felon undergoing police interrogation.” 11 Equally, for Thrift, affect in urban life is evident in the “mass hysteria” surrounding major media events like the spectacular life or the death of a global superstar or the roar of a crowd celebrating a point scored by their team in a sports stadium. To Thrift’s descriptions of the affective registers in urban culture, one could add, in the Indian context, the many ways Bollywood culture permeates the everyday lives of Indians in terms of fashion, clothing, style, song and dance, rituals, and so on. One can also point to the affective domain of “mass worship” of Bollywood stars and Bollywood culture along with the “mass fanaticism” of fans who flock to see their favorite film star at a shooting location or in a film city, or the masses of cinemagoers who insist on catching a new release in a cinema hall on the first day in cities and towns across India.
As Amit Rai’s brilliant work on affect in India’s new media assemblage demonstrates, film (in the traditional sense of movie-making and movie-going) is now only one of the many elements in a highly diffuse agglomeration of material and immaterial practices of production, distribution, and consumption in Bollywood. 12 Therefore, filmmakers have to make creative decisions about the filmmaking process in relation to a range of immaterial practices taking place—or which have already taken place—in diverse locations, such as malls, multiplexes, homes, and local marketplaces, and on multiple platforms, such as movie theaters, television channels, FM radio, online media, and cell phones. Foregrounding the affective connectivities between cinema and other media technologies along with the sensations generated among bodies, populations, and various graphical interfaces at locations such as the single-screen cinema hall, the multiplex, the mall, the television screen at home, and the mobile phone in public places, Rai redefines Bollywood as a new media assemblage that is “necessarily constellated, remediated and multiply overlapping.” 13 Rai argues that through remediation of old and new media connectivities and sensations in and through Bollywood, affect plays a crucial role in the transformation of technologies, labor, and aesthetics in production and consumption practices of everyday life in India.
In many ways, affect has always been a central concern in Indian cinema and in the production of creativity in India more generally. In Bombay before Bollywood , Rosie Thomas argues that the spectator-subject of mainstream Hindi cinema has always been addressed and moved through film primarily by affect. Tracing the genealogy of Bollywood through the history of Bombay cinema, Thomas finds that in commercial Hindi films, the emphasis was—and still is—more on emotion and spectacle and less on the tightness of a linear narrative. Or, as Thomas puts it, the emphasis was more “on how things would happen rather than what would happen next, on a succession of modes rather than linear denouement, on familiarity and repeated viewings rather than ‘originality’ and novelty, on a moral disordering to be (temporarily) resolved rather than an enigma to be solved.” 14 The pleasure value of repeat viewing, for instance, was recognized by filmmakers early on, and was built into film narratives by foregrounding the affective power of stars, music, spectacle, emotion, and dialogue. Thomas argues that affect was thus “structured and contained by narratives whose power and insistence derived from their very familiarity, coupled with the fact that they were deeply rooted (in the psyche and in traditional mythology).” 15
Thomas claims that “all Indian classical drama, dance and music draw on this aesthetic,” and argues that the traditions of rasa theory deeply inform the production practices of Indian cinema. However, she also finds that most filmmakers do not make any conscious reference to this cultural heritage. Similarly, Thomas wonders whether or not the emergence of the spectator-subject of Indian cinema—who is primarily addressed and moved by aesthetic modes of affect (rasa) in film narratives—can be related in any useful way to a more general history of the evolution of the “social audience” in India. Arguing that traditions of Bollywood cannot be used to provide neat, causal explanations of contemporary Indian cinema and culture, Thomas suggests that traditions (such as rasa theory) must be seen “as a framework of terms of reference within which certain developments have been stifled, others allowed to evolve unproblematically, and which can be used to throw light on the different possibilities of forms of address which might be expected or tolerated by an Indian audience.” 17
As Rajinder Dudrah and Amit Rai remind us, the role of affect (or rasa) in Indian cinema cannot be understood simply through critiques of the political economy of the Hindi film industry (to make money, filmmakers have to produce emotional melodramas with song and dance to reach a “mass audience”) or through cultural studies of the textual pleasures of moviegoing for spectator-subjects of Indian cinema (Indians like Bollywood films because emotional melodramas are part of their essential cultural traditions). 18 Highlighting the risks of reading rasa as the “essence” of Indian culture and cautioning against the dangers of embracing elitist or high-brahminical ideologies of rasa as the pinnacle of Hindu philosophy or aesthetics, Dudrah and Rai examine rasa in Bollywood as a “contact zone” of affect. In this zone of affective contagion, Bollywood is a new media assemblage “through and in which bodies, sensations, capital, sexualities, races, technologies and desires rub up against each other, producing differing and differential rhythms, speeds, juices (or rasas), intensities, technologies, combinations, codes, possibilities, and even languages.”
Bollywood’s affect (or rasa) thus functions as “a framework of terms of reference” at the infrastructural level of cinema and urban life for the creation of new architectures of cities and film cities in India. In the next section, I discuss how the affective value of Bollywood circulates at the infrastructural level in the immaterial production and management of mass creativity through the concept of the film city in urban India. | 2,897 | common-pile/libretexts_filtered | https://socialsci.libretexts.org/Bookshelves/Sociology/Precarious_Creativity%3A_Global_Media_Local_Labor_(Curtin_and_Sanson)/04%3A_Film_City-_Cinema_Affect_and_Immaterial_Labor_in_Urban_India/4.02%3A_Bollywoodization_Immaterial_Labor_and_Mass_Creativity | libretexts | libretexts-0000.json.gz:39724 | https://socialsci.libretexts.org/Bookshelves/Sociology/Precarious_Creativity%3A_Global_Media_Local_Labor_(Curtin_and_Sanson)/04%3A_Film_City-_Cinema_Affect_and_Immaterial_Labor_in_Urban_India/4.02%3A_Bollywoodization_Immaterial_Labor_and_Mass_Creativity |
GRbl7nYh6HoI_GeE | Vaccine Practice for Health Professionals: 1st Canadian Edition | About eCampusOntario
eCampusOntario is a not-for-profit corporation funded by the Government of Ontario. It serves as a centre of excellence in online and technology-enabled learning for all publicly funded colleges and universities in Ontario and has embarked on a bold mission to widen access to post-secondary education and training in Ontario. This textbook is part of eCampusOntario’s Open Library, which provides free learning resources in a wide range of subject areas. These open resources can be assigned by instructors for their classes, downloaded by learners to electronic devices or printed through the University of Waterloo print on demand service. These free and open resources are customizable to meet a wide range of learning needs, and we invite instructors to review and adopt the resources for use in their courses.
About the Authors
Oona St-Amant, PhD, MScN, BScN, RN, Assistant Professor, Ryerson University, Faculty of Community Services, Daphne Cockwell School of Nursing, Toronto, Ontario, Canada
Jennifer L. Lapum, PhD, MN, BScN, RN, Professor, Ryerson University, Faculty of Community Services, Daphne Cockwell School of Nursing, Toronto, Ontario, Canada
Vinita Dubey, MD, MPH, CCFP, FRCPC, Associate Medical Officer of Health, Toronto Public Health, Ontario, Canada
Kim English, RN, BScN, MN, Professor, Trent/Fleming School of Nursing, Trent University, Peterborough, Ontario, Canada
Karen Beckermann, RN, BSc, MSc(A), DPA, Associate Director, Vaccine Preventable Diseases, Toronto Public Health, Toronto, Ontario, Canada
Che-Sheu (Sue) Huang, RN, BScN, Health Promotion Specialist, Toronto Public Health, CDC – Vaccine Preventable Diseases Program, Toronto, Ontario, Canada
Carly Weeks, BA, MA, Health Reporter, The Globe and Mail, Toronto, Ontario, Canada
Kathleen Leslie, PhD, JD, RN, Assistant Professor, Faculty of Health Disciplines, Athabasca University, Athabasca, Alberta, Canada
For more information:
Dr. Oona St-Amant
Ryerson University
<EMAIL_ADDRESS>415-979-5000 ex. 7986
350 Victoria St.
Toronto, ON M5B 2K3
Note to Teachers Using This Resource
We encourage you to use this resource and would love to hear if you have integrated it into your curriculum. Please consider notifying Dr. St-Amant if you are using it in your course, identifying the healthcare discipline and the number of students. Please help us support future OER efforts by reporting your adoption of this resource at https://openlibrary.ecampusontario.ca/report-an-adoption/. | 461 | common-pile/pressbooks_filtered | https://ecampusontario.pressbooks.pub/immunizationsmohawkcollegeedition/chapter/about-ecampusontario-and-authors/ | pressbooks | pressbooks-0000.json.gz:17437 | https://ecampusontario.pressbooks.pub/immunizationsmohawkcollegeedition/chapter/about-ecampusontario-and-authors/ |
ckjL4Xig9IbTrTsc | 1.4: Basics of Singing 3- How to Learn a Song | Depending upon a person’s culture and background, one or more ways were already enculturated before that person came in contact with any formal education system that taught music. Young children are exposed to music through their parents, either singing to them or playing it for them in a variety of mediums. In today’s society, toddlers can manipulate a smart phone to play a youtube video of toddler tunes. A person is exposed to music in some form anytime there is interaction with the outside world. You can hear music in commercials, in stores, video games, even rings of a cell phone. With that said, what are the typical ways most people learn a song?
First, the general population of people learns by ear. For many generations, music was not written down, but passed on by rote (someone who knew the song would sing or play it for others, and they would copy it). Today, one hears the piece of music on some media device, and over time can sing along with the song. There are advantages and disadvantages to this method. First, an advantage is the ability to practice wherever the person is, with access to the song a smart phone away. Second, the body of music out there to hear is nearly infinite; access has never been easier than today with many ways to freely listen. Also, one can listen to different singers performing the same piece to get different takes on how to perform the piece. One disadvantage of this method is the singer’s desire to try and copy the original artist’s voice. No matter who it is, that performer’s voice is unique, as is the singer trying to copy. In order for the singer to copy the original artist, a contrived sound is created with tension in the throat. Try singing like Louie Armstrong for more than 10 seconds and you will instantly feel the extreme of this issue. Another disadvantage of this method is lack of creativity on the part of the learner. If one only learns from someone else’s style of singing, one’s own interpretation of the text and music is lost. If you have ever listened to the same song with different singers, you will notice variations in the performance. Finally, a disadvantage of learning by ear is time. If a piece of music must be sung in a great hurry for an event, then the ability to read the music fast becomes invaluable. To put this in perspective, imagine you become a famous singer. A large media corporation such as Disney calls you up and wants you to perform on the soundtrack of their next movie. The company flies you to their studio, send you to the booth with the sheet music, sets up the microphone, and is ready to record. You ask to hear a recording of the song first, and are met with blank stares. There is no recording, because you are the first. Now a great gig was lost, and your reputation is tarnished.
There is nothing wrong with learning music by ear. However, being able to learn a song several different ways gives the singer an edge over other singers, and increases the learning curve. Here are other methods to learn a song other than by a recording with the vocals: 1. Learn by rote; 2. Speak the text out loud; 3. Use sheet music; 4. Sing along with a karaoke track; 5. Sing a cappella; 6. Record yourself; and 7. Solfedge.
Learning by rote simply means someone sings a line of the song and you sing it back. Cultures have taught music in this way for millennia, and some religious groups still use this method today in services where a leader sings a line, and the congregation responds. If learning a song by rote, typically a person sings a line (or phrase), then sings a second phrase, puts them together, sings a third, adds that, and so on. Many people who teach groups to sing use this method.
Speaking the text of the song out loud is a technique for understanding the meaning of the lyrics, as well as a way to decide what is the most important word of each phrase (more on that later). The act of speaking it audibly is important for this technique to have its full effect. Try looking up the lyrics to a song you know already somewhat well. Speak the text, and then listen to the song. You may notice the meanings of parts of the song seem different. You are now linking meaning to words that were not important before you underwent this exercise. This can also help with memorization of songs.
Using sheet music to learn a song is standard practice in most formal voice lessons. Music reading literacy is like reading literacy; it opens up new ways to learn material, sometimes more quickly. If you have never read music before, it can be daunting to look at a piece of music. There are many instructional methods out there to learn how to read music. Just learning the note names and how long you hold a note (rhythm) is just the beginning (like learning the alphabet). A simple open resource can be found here: http://www.wikihow.com/Read-Music
Singing along with a karaoke track is a method to utilize after you feel comfortable singing the song with the vocals behind you. Some singers feel very confident singing with the vocal track behind them, and then when it is removed, suddenly their voice goes away. This is due to a subconscious method for singing where the singer is hearing the voice and then following it a split second later. I call it “cheat-singing.” You are only cheating yourself when using this, because as soon as the other vocal is not there, you are stuck. Singing with a karaoke track, or a live accompaniment if available, eliminates cheat singing as an option (unless the accompanist is playing your notes and you are cheat-singing to that). The track also assists the singer in reminding them of the right pitch centers, something not available if the singer sings without any accompaniment, or a cappella.
There is an advantage to singing a cappella. Without anything to use as a crutch, the singer is forced to sing solo. This exposes any vocal issues that were hiding behind either the accompaniment or the other vocalist. It can be hard to diagnose all issues listening and singing at the same time. That’s where recording yourself is useful. Very few people actually enjoy listening to themselves sing. In a recording, the singer hears how he or she sounds to everyone else. This can be discouraging, but useful as a tool to improve. Video recording is a better method than just audio, because any physical issues that occur can be diagnosed as well (ex. You see your head leaning forward when trying to sing a high note).
Solfedge is a system to learn music developed by a Hungarian named Zoltan Kodály. He created a system of syllables for notes in the scale (Do-re-mi-fa-sol-la-ti-do), which in turn help the singer know what direction the note tends to move. It helped save Hungarian folk music, which was in danger of disappearing altogether. Once a singer learns the system, singing a phrase for the first time becomes easier (cue Sound of Music). This is an excellent method for sight reading music. Excellent sight readers can look at a piece of music, and sing it correctly the first time without hearing it. Professional sight readers are employed all around the world, in church choirs, radio choirs in Europe, and media companies.
One method of learning a song by itself is not better or worse than another. However, if the singer uses the best of all methods, he or she can learn music well and quickly.
Supplemental Videos
Assignment on Videos
After watching the demonstration video, enter the secret number at the top of your assignment.
Write in complete sentences answers to the following questions.
1. In your own words, what was the content of the video?
2. What are two things you found most interesting about the content of the video?
3. Think of a singer you have seen and heard. Who are they, and what do they demonstrate in terms of this concept?
4. Name 3 positive things you do while singing that relate to this concept.
5. What 2 things can you improve on relating to this concept? | 1,838 | common-pile/libretexts_filtered | https://human.libretexts.org/Bookshelves/Music/Music_Performance/Voice_Class_(Fisher)/01%3A_Unit_1/1.04%3A_Basics_of_Singing_3-_How_to_Learn_a_Song | libretexts | libretexts-0000.json.gz:31788 | https://human.libretexts.org/Bookshelves/Music/Music_Performance/Voice_Class_(Fisher)/01%3A_Unit_1/1.04%3A_Basics_of_Singing_3-_How_to_Learn_a_Song |
6BXfSuDUpjvnE7fp | 3.1: Regulations | 3.1: Regulations
SBX7-7
For many years, water agencies conducted water conservation programs as public outreach. They often set goals of fairly minimal savings over long periods of time—in other words, goals that were easy to achieve. Rebates were intended to help people save water, but also make them feel good and appreciate the water agency at the same time. Meanwhile, water agencies often had their own revenues in mind. They did not want people to be wasteful with water, but they also calculated a certain demand in order to set rates. They did not want too much conservation without planning for a reduction in revenue.
SBX7-7 changed everything. In 2009, Governor Schwarzenegger signed into law SBX7-7, the Water Conservation Act of 2009, which required retail water suppliers to determine their baseline per capita water use and reduce water use by 20% of their baseline by 2020.
What happens if a retail water supplier misses its target? Compliance with SBX7-7 determines eligibility for state water grants and loans. Failure to meet the target establishes a violation of law for administrative or judicial proceedings. This means a supplier wouldn’t be eligible for many grants and loans that suppliers rely on to fund infrastructure, and could have legal actions taken against it.
No doubt in 2020 some water suppliers will not meet SBX7-7 goals either intentionally or unintentionally. What will actually happen to them? Some may be penalized with proceedings and some may not be because they made a good faith effort. This will be interesting to see.
State Water Resources Control Board Mandatory Measures
While SBX7-7 set a long-term goal of 20% by 2020, in July of 2014, mandatory measures from the State Water Resources Control Board (SWRCB) were enacted to combat the severity of the drought. The table below walks you through the executive and regulatory decisions about the drought.
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January 2014 |
Governor Brown declared a drought state of emergency. |
|
April 2014 |
Governor Brown signed an Executive Order (April 2014 Proclamation), which asked for reductions of 20% by all Californians with an emphasis on outdoor conservation. The order prohibited HOAs from punishing homeowners who limit their watering, |
|
July 2014 |
State Water Resource Control Board (SWRCB) asked for mandatory reductions with an emphasis on outdoor reductions. |
|
March 2015 |
SWRCB adopted an expanded mandatory emergency conservation regulation, which prohibited:
Water suppliers are tasked with enforcement and ordered to report data monthly to the SWRCB. |
|
April 2015 |
Governor Brown directed the SWRCB to implement mandatory water reductions in urban areas to reduce urban use overall by 25% compared to 2013. Instructions to the SWRCB included considering relative per capita water usage of each supplier’s service area and requiring areas with higher use to cut consumption more. |
|
May 2015 |
SWRCB adopted an emergency conservation regulation with residential gallons per capita per day (R-GPCD targets). |
|
January 2016 |
Mandatory measures are extended through October 2016 with adjustments to R-GPCD possible for suppliers for climate and growth. |
|
May 2016 |
Prohibited measures described above become permanent. Water suppliers are allowed to “self-certify” their conservation targets by analyzing their water demand (average of 2013 and 2014) and their water supply and using a target for any shortfall. |
So while SBX7-7 concentrated on long-term conservation goals compared to a baseline of total water production, the SWRCB mandatory measures concentrated on short-term conservation goals, particularly in the residential sector and particularly outdoors.
The goals (or targets) were widely criticized for not being fair. This is usually referred to as having "equity issues." While the SWRCB separated out commercial, industrial and institutional water use and concentrated strictly on a residential water reduction, it tended to penalize the water suppliers with higher per capita consumption with larger goals. Water suppliers with higher per capita consumption tended to be inland areas with higher water demand—meaning it was simply hotter inland and the plant water needs were much greater.
And then the winter of 2017 was wet. In Northern California, it was unbelievably wet breaking records. In Southern California, it was slightly wetter than average. In the Santa Clarita Valley, while it "felt" like a break from the drought, you can see that Water Year 16/17 (October 2016 – September 2017) was only slightly wetter than average with around 20 inches of rain for the entire year.
Is the drought over? Certainly, if you rely on imported water from the State Water Project, there was plenty of water in 2017. But most Southern California communities that used groundwater still found their groundwater supplies below average. For some parts of Southern California, including Ventura and Santa Barbara Counties, the drought was definitely not over. Looking at the graph above, would you say the drought was over in the Santa Clarita Valley?
As of this writing, the State Water Resources Control Board is implementing targets by service area to include an indoor component, a landscape component, a water loss requirement, and separate measures for commercial, industrial, and institutional users.
Building Codes
What type of regulations govern the building of a home? In terms of water use, how does a developer decide what type of toilet to use? Or aerators to install? Or landscaping to put in? These sorts of choices are governed by layers of codes, including city, county, state, and federal. In most instances, when there are overlapping standards, the most stringent apply.
Cal Green Building Code (2014 update)
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Indoors |
Water Use |
|
Toilets |
1.28 gallons per flush |
|
Showerheads |
2.0 gallons per minute at 80 psi |
|
Bathroom faucets |
1.2 gallons at 60 psi |
|
Kitchen faucets |
1.8 gallons at 60 psi |
|
Outdoor |
|
|
Controllers |
All controllers shall be weather-based or soil-moisture-based and shall have a rain shut off |
All of the indoor devices listed above have a specific flow or flush rate. This is the rate from the manufacturer and may not be the rate in real life. Toilets, for example, leak over time and may use more than 1.28 gallons per flush. Similarly, faucets have a rating at 60 pounds per square inch, but it is entirely possible to have more pressure inside a house and use more water because of it.
Building codes are very useful in driving long-term demand downwards, primarily inside the home. In California; if there was a change to the code that forbid turf grass from being installed in new homes, demand could be driven down further outside rather than simply relying on controllers.
The graph above shows the savings in 2020 in the Santa Clarita Valley as a result of various measures, including incentives (rebates), plumbing code and standards, pricing and water loss reduction. Note that 9% of the savings are from conservation pricing and 25% of the savings are from plumbing codes and standards. These are powerful ways to drive demand down.
Try It!
Conduct a quick inventory of a bathroom at home. What can you tell about the flow rate of these devices?
|
Toilets |
___________ gallons per flush |
|
Showerheads |
___________ gallons per minute at 80 psi |
|
Bathroom faucets |
___________ gallons at 60 psi |
- Which type of regulation (SBX7-7, SWRCB restrictions, or Building Code) do you think will result in the most savings over time?
- Which measure prohibited by the SWRCB would be the most difficult for customers to prevent? | 1,630 | common-pile/libretexts_filtered | https://workforce.libretexts.org/Bookshelves/Water_Systems_Technology/Water_132%3A_Water_Supply_and_Demand_in_California_(Anagnoson)/03%3A_Demand-Side_Management/3.01%3A_Regulations | libretexts | libretexts-0000.json.gz:45179 | https://workforce.libretexts.org/Bookshelves/Water_Systems_Technology/Water_132%3A_Water_Supply_and_Demand_in_California_(Anagnoson)/03%3A_Demand-Side_Management/3.01%3A_Regulations |
F9xyVtQJT-Q75grx | A Vindication of the Rights of Woman | A Vindication of the Rights of Woman
Chapter 7: Modesty Comprehensively Considered and Not as a Sexual Virtue
Modesty! Sacred offspring of sensibility and reason! true delicacy of mind! may I unblamed presume to investigate thy nature, and trace to its covert the mild charm, that mellowing each harsh feature of a character, renders what would otherwise only inspire cold admiration—lovely! Thou that smoothest the wrinkles of wisdom, and softenest the tone of the more sublime virtues till they all melt into humanity! thou that spreadest the ethereal cloud that surrounding love heightens every beauty, it half shades, breathing those coy sweets that steal into the heart, and charm the senses—modulate for me the language of persuasive reason, till I rouse my sex from the flowery bed, on which they supinely sleep life away!
In speaking of the association of our ideas, I have noticed two distinct modes; and in defining modesty, it appears to me equally proper to discriminate that purity of mind, which is the effect of chastity, from a simplicity of character that leads us to form a just opinion of ourselves, equally distant from vanity or presumption, though by no means incompatible with a lofty consciousness of our own dignity. Modesty in the latter signification of the term, is that soberness of mind which teaches a man not to think more highly of himself than he ought to think, and should be distinguished from humility, because humility is a kind of self-abasement. A modest man often conceives a great plan, and tenaciously adheres to it, conscious of his own strength, till success gives it a sanction that determines its character. Milton was not arrogant when he suffered a suggestion of judgment to escape him that proved a prophesy; nor was General Washington when he accepted of the command of the American forces. The latter has always been characterized as a modest man; but had he been merely humble, he would probably have shrunk back irresolute, afraid of trusting to himself the direction of an enterprise on which so much depended.
A modest man is steady, an humble man timid, and a vain one presumptuous; this is the judgment, which the observation of many characters, has led me to form. Jesus Christ was modest, Moses was humble, and Peter vain.
Thus discriminating modesty from humility in one case, I do not mean to confound it with bashfulness in the other. Bashfulness, in fact, is so distinct from modesty, that the most bashful lass, or raw country lout, often becomes the most impudent; for their bashfulness being merely the instinctive timidity of ignorance, custom soon changes it into assurance.[1]
The shameless behaviour of the prostitutes who infest the streets of London, raising alternate emotions of pity and disgust, may serve to illustrate this remark. No, they were only bashful, shame-faced innocents; and losing their innocence, their shame-facedness was rudely brushed off; a virtue would have left some vestiges in the mind, had it been sacrificed to passion, to make us respect the grand ruin.
Purity of mind, or that genuine delicacy, which is the only virtuous support of chastity, is near a-kin to that refinement of humanity, which never resides in any but cultivated minds. It is something nobler than innocence; it is the delicacy of reflection, and not the coyness of ignorance. The reserve of reason, which like habitual cleanliness, is seldom seen in any great degree, unless the soul is active, may easily be distinguished from rustic shyness or wanton skittishness; and so far from being incompatible with knowledge, it is its fairest fruit. What a gross idea of modesty had the writer of the following remark! “The lady who asked the question whether women may be instructed in the modern system of botany, consistently with female delicacy?” was accused of ridiculous prudery: nevertheless, if she had proposed the question to me, I should certainly have answered—They cannot.” Thus is the fair book of knowledge to be shut with an everlasting seal! On reading similar passages I have reverentially lifted up my eyes and heart to Him who liveth for ever and ever, and said, O my Father, hast Thou by the very constitution of her nature forbid Thy child to seek Thee in the fair forms of truth? And, can her soul be sullied by the knowledge that awfully calls her to Thee?
I have then philosophically pursued these reflections till I inferred, that those women who have most improved their reason must have the most modesty —though a dignified sedateness of deportment may have succeeded the playful, bewitching bashfulness of youth.[2]
And thus have I argued. To render chastity the virtue from which unsophisticated modesty will naturally flow, the attention should be called away from employments, which only exercise the sensibility; and the heart made to beat time to humanity, rather than to throb with love. The regulation of the behaviour is not modesty, though those who study rules of decorum, are, in general termed modest women. Make the heart clean, let it expand and feel for all that is human, instead of being narrowed by selfish passions; and let the mind frequently contemplate subjects that exercise the understanding, without heating the imagination, and artless modesty will give the finishing touches to the picture.
She who can discern the dawn of immortality, in the streaks that shoot athwart the misty night of ignorance, promising a clearer day, will respect, as a sacred temple, the body that enshrines such an improvable soul. True love, likewise, spreads this kind of mysterious sanctity round the beloved object, making the lover most modest when in her presence. So reserved is affection, that, receiving or returning personal endearments, it wishes, not only to shun the human eye, as a kind of profanation; but to diffuse an encircling cloudy obscurity to shut out even the saucy sparkling sunbeams. Yet, that affection does not deserve the epithet of chaste which does not receive a sublime gloom of tender melancholy, that allows the mind for a moment to stand still and enjoy the present satisfaction, when a consciousness of the Divine presence is felt—for this must ever be the food of joy!
As I have always been fond of tracing to its source in nature any prevailing custom, I have frequently thought that it was a sentiment of affection for whatever had touched the person of an absent or lost friend, which gave birth to that respect for relics, so much abused by selfish priests. Devotion, or love, may be allowed to hallow the garments as well as the person; for the lover must want fancy, who has not a sort of sacred respect for the glove or slipper of his mistress. He could not confound them with vulgar things of the same kind.
This fine sentiment, perhaps, would not bear to be analyzed by the experimental philosopher—but of such stuff is human rapture made up!— A shadowy phantom glides before us, obscuring every other object; yet when the soft cloud is grasped, the form melts into common air, leaving a solitary void, or sweet perfume, stolen from the violet, that memory long holds dear. But, I have tripped unawares on fairy ground, feeling the balmy gale of spring stealing on me, though November frowns.
As a sex, women are more chaste than men, and as modesty is the effect of chastity, they may deserve to have this virtue ascribed to them in rather an appropriated sense; yet, I must be allowed to add an hesitating if:— for I doubt, whether chastity will produce modesty, though it may propriety of conduct, when it is merely a respect for the opinion of the world, and when coquetry and the lovelorn tales of novelists employ the thoughts. Nay, from experience, and reason, I should be lead to expect to meet with more modesty amongst men than women, simply because men exercise their understandings more than women.
But, with respect to propriety of behaviour, excepting one class of females, women have evidently the advantage. What can be more disgusting than that impudent dross of gallantry, thought so manly, which makes many men stare insultingly at every female they meet? Is this respect for the sex? This loose behaviour shows such habitual depravity, such weakness of mind, that it is vain to expect much public or private virtue, till both men and women grow more modest—till men, curbing a sensual fondness for the sex, or an affectation of manly assurance, more properly speaking, impudence, treat each other with respect—unless appetite or passion gives the tone, peculiar to it, to their behaviour. I mean even personal respect—the modest respect of humanity, and fellow-feeling; not the libidinous mockery of gallantry, nor the insolent condescension of protectorship.
To carry the observation still further, modesty must heartily disclaim, and refuse to dwell with that debauchery of mind, which leads a man coolly to bring forward, without a blush, indecent allusions, or obscene witticisms, in the presence of a fellow creature; women are now out of the question, for then it is brutality. Respect for man, as man is the foundation of every noble sentiment. How much more modest is the libertine who obeys the call of appetite or fancy, than the lewd joker who sets the table in a roar.
This is one of the many instances in which the sexual distinction respecting modesty has proved fatal to virtue and happiness. It is, however, carried still further, and woman, weak woman! made by her education the slave of sensibility, is required, on the most trying occasions, to resist that sensibility. “Can any thing,” says Knox, be more absurd than keeping women in a state of ignorance, and yet so vehemently to insist on their resisting temptation? Thus when virtue or honour make it proper to check a passion, the burden is thrown on the weaker shoulders, contrary to reason and true modesty, which, at least, should render the self-denial mutual, to say nothing of the generosity of bravery, supposed to be a manly virtue.
In the same strain runs Rousseau’s and Dr. Gregory’s advice respecting modesty, strangely miscalled! for they both desire a wife to leave it in doubt, whether sensibility or weakness led her to her husband’s arms. The woman is immodest who can let the shadow of such a doubt remain on her husband’s mind a moment.
But to state the subject in a different light. The want of modesty, which I principally deplore as subversive of morality, arises from the state of warfare so strenuously supported by voluptuous men as the very essence of modesty, though, in fact, its bane; because it is a refinement on sensual desire, that men fall into who have not sufficient virtue to relish the innocent pleasures of love. A man of delicacy carries his notions of modesty still further, for neither weakness nor sensibility will gratify him—he looks for affection.
Again; men boast of their triumphs over women, what do they boast of? Truly the creature of sensibility was surprised by her sensibility into folly—into vice;[3] and the dreadful reckoning falls heavily on her own weak head, when reason wakes. For where art thou to find comfort, forlorn and disconsolate one? He who ought to have directed thy reason, and supported thy weakness, has betrayed thee! In a dream of passion thou consentedst to wander through flowery lawns, and heedlessly stepping over the precipice to which thy guide, instead of guarding, lured thee, thou startest from thy dream only to face a sneering, frowning world, and to find thyself alone in a waste, for he that triumphed in thy weakness is now pursuing new conquests; but for thee—there is no redemption on this side the grave! And what resource hast thou in an enervated mind to raise a sinking heart?
But, if the sexes be really to live in a state of warfare, if nature has pointed it out, let men act nobly, or let pride whisper to them, that the victory is mean when they merely vanquish sensibility. The real conquest is that over affection not taken by surprise—when, like Heloisa, a woman gives up all the world, deliberately, for love. I do not now consider the wisdom or virtue of such a sacrifice, I only contend that it was a sacrifice to affection, and not merely to sensibility, though she had her share. And I must be allowed to call her a modest woman, before I dismiss this part of the subject, by saying, that till men are more chaste, women will be immodest. Where, indeed, could modest women find husbands from whom they would not continually turn with disgust? Modesty must be equally cultivated by both sexes, or it will ever remain a sickly hot-house plant, whilst the affectation of it, the fig leaf borrowed by wantonness, may give a zest to voluptuous enjoyments.)
Men will probably still insist that woman ought to have more modesty than man; but it is not dispassionate reasoners who will most earnestly oppose my opinion. No, they are the men of fancy, the favourites of the sex, who outwardly respect, and inwardly despise the weak creatures whom they thus sport with. They cannot submit to resign the highest sensual gratification, nor even to relish the epicurism of virtue—self-denial.
To take another view of the subject, confining my remarks to women.
The ridiculous falsities which are told to children, from mistaken notions of modesty, tend very early to inflame their imaginations and set their little minds to work, respecting subjects, which nature never intended they should think of, till the body arrived at some degree of maturity; then the passions naturally begin to take place of the senses, as instruments to unfold the understanding, and form the moral character.
In nurseries, and boarding schools, I fear, girls are first spoiled; particularly in the latter. A number of girls sleep in the same room, and wash together. And, though I should be sorry to contaminate an innocent creature’s mind by instilling false delicacy, or those indecent prudish notions, which early cautions respecting the other sex naturally engender, I should be very anxious to prevent their acquiring indelicate, or immodest habits; and as many girls have learned very indelicate tricks, from ignorant servants, the mixing them thus indiscriminately together, is very improper.
To say the truth, women are, in general, too familiar with each other, which leads to that gross degree of familiarity that so frequently renders the marriage state unhappy. Why in the name of decency are sisters, female intimates, or ladies and their waiting women, to be so grossly familiar as to forget the respect which one human creature owes to another? But, why women in health should be more familiar with each other than men are, when they boast of their superiour delicacy, is a solecism in manners which I could never solve.
In order to preserve health and beauty, I should earnestly recommend frequent ablutions, to dignify my advice that it may not offend the fastidious ear; and, by example, girls ought to be taught to wash and dress alone, without any distinction of rank; and if custom should make them require some little assistance, let them not require it till that part of the business is over which ought never to be done before a fellow-creature; because it is an insult to the majesty of human nature. Not on the score of modesty, but decency; for the care which some modest women take, making at the same time a display of that care, not to let their legs be seen, is as childish as immodest.[4]
I could proceed still further, till I animadverted on some still more indelicate customs, which men never fall into. Secrets are told—where silence ought to reign; and that regard to cleanliness, which some religious sects have, perhaps, carried too far, especially the Essenes, amongst the Jews, by making that an insult to God which is only an insult to humanity, is violated in a brutal manner. How can DELICATE women obtrude on notice that part of the animal economy, which is so very disgusting? And is it not very rational to conclude, that the women who have not been taught to respect the human nature of their own sex, in these particulars, will not long respect the mere difference of sex, in their husbands? After their maidenish bashfulness is once lost, I, in fact, have generally observed, that women fall into old habits; and treat their husbands as they did their sisters or female acquaintance.
Besides, women from necessity, because their minds are not cultivated, have recourse very often, to what I familiarly term bodily wit; and their intimacies are of the same kind. In short, with respect to both mind and body, they are too intimate. That decent personal reserve, which is the foundation of dignity of character, must be kept up between women, or their minds will never gain strength or modesty.
On this account also, I object to many females being shut up together in nurseries, schools, or convents. I cannot recollect without indignation, the jokes and hoiden tricks, which knots of young women indulged themselves in, when in my youth accident threw me, an awkward rustic, in their way. They were almost on a par with the double meanings, which shake the convivial table when the glass has circulated freely. But it is vain to attempt to keep the heart pure, unless the head is furnished with ideas, and set to work to compare them, in order, to acquire judgment, by generalizing simple ones; and modesty by making the understanding damp the sensibility.
It may be thought that I lay too great a stress on personal reserve; but it is ever the hand-maid of modesty. So that were I to name the graces that ought to adorn beauty, I should instantly exclaim, cleanliness, neatness, and personal reserve. It is obvious, I suppose, that the reserve I mean, has nothing sexual in it, and that I think it EQUALLY necessary in both sexes. So necessary indeed, is that reserve and cleanliness which indolent women too often neglect, that I will venture to affirm, that when two or three women live in the same house, the one will be most respected by the male part of the family, who reside with them, leaving love entirely out of the question, who pays this kind of habitual respect to her person.
When domestic friends meet in a morning, there will naturally prevail an affectionate seriousness, especially, if each look forward to the discharge of daily duties; and it may be reckoned fanciful, but this sentiment has frequently risen spontaneously in my mind. I have been pleased after breathing the sweet bracing morning air, to see the same kind of freshness in the countenances I particularly loved; I was glad to see them braced, as it were, for the day, and ready to run their course with the sun. The greetings of affection in the morning are by these means more respectful, than the familiar tenderness which frequently prolongs the evening talk. Nay, I have often felt hurt, not to say disgusted, when a friend has appeared, whom I parted with full dressed the evening before, with her clothes huddled on, because she chose to indulge herself in bed till the last moment.
Domestic affection can only be kept alive by these neglected attentions; yet if men and women took half as much pains to dress habitually neat, as they do to ornament, or rather to disfigure their persons, much would be done towards the attainment of purity of mind. But women only dress to gratify men of gallantry; for the lover is always best pleased with the simple garb that sits close to the shape. There is an impertinence in ornaments that rebuffs affection; because love always clings round the idea of home.
As a sex, women are habitually indolent; and every thing tends to make them so. I do not forget the starts of activity which sensibility produces; but as these flights of feeling only increase the evil, they are not to be confounded with the slow, orderly walk of reason. So great, in reality, is their mental and bodily indolence, that till their body be strengthened and their understanding enlarged by active exertions, there is little reason to expect that modesty will take place of bashfulness. They may find it prudent to assume its semblance; but the fair veil will only be worn on gala days.
Perhaps there is not a virtue that mixes so kindly with every other as modesty. It is the pale moon-beam that renders more interesting every virtue it softens, giving mild grandeur to the contracted horizon. Nothing can be more beautiful than the poetical fiction, which makes Diana with her silver crescent, the goddess of chastity. I have sometimes thought, that wandering with sedate step in some lonely recess, a modest dame of antiquity must have felt a glow of conscious dignity, when, after contemplating the soft shadowy landscape, she has invited with placid fervour the mild reflection of her sister’s beams to turn to her chaste bosom.
A Christian has still nobler motives to incite her to preserve her chastity and acquire modesty, for her body has been called the Temple of the living God; of that God who requires more than modesty of mien. His eye searcheth the heart; and let her remember, that if she hopeth to find favour in the sight of purity itself, her chastity must be founded on modesty, and not on worldly prudence; or verily a good reputation will be her only reward; for that awful intercourse, that sacred communion, which virtue establishes between man and his Maker, must give rise to the wish of being pure as he is pure!
After the foregoing remarks, it is almost superfluous to add, that I consider all those feminine airs of maturity, which succeed bashfulness, to which truth is sacrificed, to secure the heart of a husband, or rather to force him to be still a lover when nature would, had she not been interrupted in her operations, have made love give place to friendship, as immodest. The tenderness which a man will feel for the mother of his children is an excellent substitute for the ardour of unsatisfied passion; but to prolong that ardour it is indelicate, not to say immodest, for women to feign an unnatural coldness of constitution. Women as well as men ought to have the common appetites and passions of their nature, they are only brutal when unchecked by reason: but the obligation to check them is the duty of mankind, not a sexual duty. Nature, in these respects, may safely be left to herself; let women only acquire knowledge and humanity, and love will teach them modesty.[5] There is no need of falsehoods, disgusting as futile, for studied rules of behaviour only impose on shallow observers; a man of sense soon sees through, and despises the affectation.
The behaviour of young people, to each other, as men and women, is the last thing that should be thought of in education. In fact, behaviour in most circumstances is now so much thought of, that simplicity of character is rarely to be seen; yet, if men were only anxious to cultivate each virtue, and let it take root firmly in the mind, the grace resulting from it, its natural exteriour mark, would soon strip affectation of its flaunting plumes; because, fallacious as unstable, is the conduct that is not founded upon truth!
Would ye, O my sisters, really possess modesty, ye must remember that the possession of virtue, of any denomination, is incompatible with ignorance and vanity! ye must acquire that soberness of mind, which the exercise of duties, and the pursuit of knowledge, alone inspire, or ye will still remain in a doubtful dependent situation, and only be loved whilst ye are fair! the downcast eye, the rosy blush, the retiring grace, are all proper in their season; but modesty, being the child of reason, cannot long exist with the sensibility that is not tempered by reflection. Besides, when love, even innocent love, is the whole employ of your lives, your hearts will be too soft to afford modesty that tranquil retreat, where she delights to dwell, in close union with humanity.
- "Such is the country-maiden's fright, When first a red-coat is in sight; Behind the door she hides her face, Next time at distance eyes the lace: She now can all his terrors stand, Nor from his squeeze withdraws her hand, She plays familiar in his arms, And every soldier hath his charms; >From tent to tent she spreads her flame; For custom conquers fear and shame." ↵
- Modesty, is the graceful calm virtue of maturity; bashfulness, the charm of vivacious youth. ↵
- The poor moth fluttering round a candle, burns its wings. ↵
- I remember to have met with a sentence, in a book of education that made me smile. "It would be needless to caution you against putting your hand, by chance, under your neck-handkerchief; for a modest woman never did so!" ↵
- The behaviour of many newly married women has often disgusted me. They seem anxious never to let their husbands forget the privilege of marriage, and to find no pleasure in his society unless he is acting the lover. Short, indeed, must be the reign of love, when the flame is thus constantly blown up, without its receiving any solid fuel. ↵ | 5,543 | common-pile/pressbooks_filtered | https://pressbooks.library.torontomu.ca/avindicationoftherightsofwoman/chapter/7/ | pressbooks | pressbooks-0000.json.gz:89098 | https://pressbooks.library.torontomu.ca/avindicationoftherightsofwoman/chapter/7/ |
S5SPeOjS-y2i04nb | 19.2: Bayesian Hypothesis Tests | 19.2: Bayesian Hypothesis Tests
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In Chapter 11 I described the orthodox approach to hypothesis testing. It took an entire chapter to describe, because null hypothesis testing is a very elaborate contraption that people find very hard to make sense of. In contrast, the Bayesian approach to hypothesis testing is incredibly simple. Let’s pick a setting that is closely analogous to the orthodox scenario. There are two hypotheses that we want to compare, a null hypothesis h 0 and an alternative hypothesis h 1 . Prior to running the experiment we have some beliefs P(h) about which hypotheses are true. We run an experiment and obtain data d. Unlike frequentist statistics Bayesian statistics does allow to talk about the probability that the null hypothesis is true. Better yet, it allows us to calculate the posterior probability of the null hypothesis , using Bayes’ rule:
\(\ P(h_0 | d) = \dfrac{P(d | h_0)P(h_0)}{P(d)}\)
This formula tells us exactly how much belief we should have in the null hypothesis after having observed the data d. Similarly, we can work out how much belief to place in the alternative hypothesis using essentially the same equation. All we do is change the subscript:
\(\ P(h_1 | d) = \dfrac{P(d | h_1)P(h_1)}{P(d)}\)
It’s all so simple that I feel like an idiot even bothering to write these equations down, since all I’m doing is copying Bayes rule from the previous section. 259
Bayes factor
In practice, most Bayesian data analysts tend not to talk in terms of the raw posterior probabilities P(h 0 |d) and P(h 1 |d). Instead, we tend to talk in terms of the posterior odds ratio. Think of it like betting. Suppose, for instance, the posterior probability of the null hypothesis is 25%, and the posterior probability of the alternative is 75%. The alternative hypothesis is three times as probable as the null, so we say that the odds are 3:1 in favour of the alternative. Mathematically, all we have to do to calculate the posterior odds is divide one posterior probability by the other:
\(\ \dfrac{P(h_1 | d)}{P(h_0 | d)}=\dfrac{0.75}{0.25}=3\)
Or, to write the same thing in terms of the equations above:
\(\ \dfrac{P(h_1 | d)}{P(h_0 | d)} = \dfrac{P(d | h_1)}{P(d | h_0)} \times \dfrac{P(h_1)}{P(h_0)}\)
Actually, this equation is worth expanding on. There are three different terms here that you should know. On the left hand side, we have the posterior odds, which tells you what you believe about the relative plausibilty of the null hypothesis and the alternative hypothesis after seeing the data. On the right hand side, we have the prior odds , which indicates what you thought before seeing the data. In the middle, we have the Bayes factor , which describes the amount of evidence provided by the data:
The Bayes factor (sometimes abbreviated as BF ) has a special place in the Bayesian hypothesis testing, because it serves a similar role to the p-value in orthodox hypothesis testing: it quantifies the strength of evidence provided by the data, and as such it is the Bayes factor that people tend to report when running a Bayesian hypothesis test. The reason for reporting Bayes factors rather than posterior odds is that different researchers will have different priors. Some people might have a strong bias to believe the null hypothesis is true, others might have a strong bias to believe it is false. Because of this, the polite thing for an applied researcher to do is report the Bayes factor. That way, anyone reading the paper can multiply the Bayes factor by their own personal prior odds, and they can work out for themselves what the posterior odds would be. In any case, by convention we like to pretend that we give equal consideration to both the null hypothesis and the alternative, in which case the prior odds equals 1, and the posterior odds becomes the same as the Bayes factor.
Interpreting Bayes factors
One of the really nice things about the Bayes factor is the numbers are inherently meaningful. If you run an experiment and you compute a Bayes factor of 4, it means that the evidence provided by your data corresponds to betting odds of 4:1 in favour of the alternative. However, there have been some attempts to quantify the standards of evidence that would be considered meaningful in a scientific context. The two most widely used are from Jeffreys (1961) and Kass and Raftery (1995). Of the two, I tend to prefer the Kass and Raftery (1995) table because it’s a bit more conservative. So here it is:
| Bayes factor | Interpretation |
|---|---|
| 1 - 3 | Negligible evidence |
| 3 - 20 | Positive evidence |
| 20 - 150 | Strong evidence |
| $>$150 | Very strong evidence |
And to be perfectly honest, I think that even the Kass and Raftery standards are being a bit charitable. If it were up to me, I’d have called the “positive evidence” category “weak evidence”. To me, anything in the range 3:1 to 20:1 is “weak” or “modest” evidence at best. But there are no hard and fast rules here: what counts as strong or weak evidence depends entirely on how conservative you are, and upon the standards that your community insists upon before it is willing to label a finding as “true”.
In any case, note that all the numbers listed above make sense if the Bayes factor is greater than 1 (i.e., the evidence favours the alternative hypothesis). However, one big practical advantage of the Bayesian approach relative to the orthodox approach is that it also allows you to quantify evidence for the null. When that happens, the Bayes factor will be less than 1. You can choose to report a Bayes factor less than 1, but to be honest I find it confusing. For example, suppose that the likelihood of the data under the null hypothesis P(d|h 0 ) is equal to 0.2, and the corresponding likelihood P(d|h 0 ) under the alternative hypothesis is 0.1. Using the equations given above, Bayes factor here would be:
\(\ BF=\dfrac{P(d | h_1)}{P(d | h_0}=\dfrac{0.1}{0.2}=0.5\)
Read literally, this result tells is that the evidence in favour of the alternative is 0.5 to 1. I find this hard to understand. To me, it makes a lot more sense to turn the equation “upside down”, and report the amount op evidence in favour of the null . In other words, what we calculate is this:
\(\ BF^{\prime} = \dfrac{P(d | h_0)}{P(d | h_1)}=\dfrac{0.2}{0.1}=2\)
And what we would report is a Bayes factor of 2:1 in favour of the null. Much easier to understand, and you can interpret this using the table above. | 1,466 | common-pile/libretexts_filtered | https://stats.libretexts.org/Courses/Cerritos_College/Introduction_to_Statistics_with_R/19%3A_Bayesian_Statistics/19.02%3A_Bayesian_Hypothesis_Tests | libretexts | libretexts-0000.json.gz:9917 | https://stats.libretexts.org/Courses/Cerritos_College/Introduction_to_Statistics_with_R/19%3A_Bayesian_Statistics/19.02%3A_Bayesian_Hypothesis_Tests |
Q-_qGr70hPQvt6xO | Machine-gun drill regulations : provisional, 1917 / prepared and ed. at the Army War College, December, 1917. | upon a straight line.
Band of fire: A band of fire is formed when the cone_of fire^ is directed at one point and the gun is so elevated that the rnaxHGiun ordinate of the trajectory will not be greater than the^ height of a man. " ' ^
gun, when the leaf is laid down.
Barrage (curtain of fire) : A machine-gun barrage is the combined sheaf of several p;i,ii],^ i\\ }nr\^, rmio-P It may be employed defensively, but, normally, it is delivered over the heads of friendly troops to cover their advance. AYhen it is moved forv/ard by time table, or at a stated distance in advance of the leading elements of the attack, it is termed a creeping barragr.
diis fire two or more guns must be employed, and such differences made in the elevation of the guns or each pair of guns tliat their beaten zones will overlap and a greater total depth of beaten zone be thus secured.
Combined sigJits and searching fire: As a means of adjustment, ^ must not be confused with tliese methods Vviien used in Are for eft'ect. As a method of adjustment, they are used wheix_the range can not be determined with suflicient precision to admit of the use of a single elevation. In fire for effect they are used on cleep targets, which would be but partially covered by a single elevatTon.
sumed to bo 12 inches.
Distance: Space betwecm elements in the direction of depth. Distance is measured from the back of tlie man in front to the breast of the man in rear. The distance between ranks is 40 inches in both line and column.
Distributed fire, traversing fire, or trap traversing: This method of fire is employed against linear targets and is applied by means of a series of short bursts, of from 5 to 10 shots. The object being to_cover_as wide a front as possible with effective ,^X^ and v\'ithout using more" mhmunifion than is absolutely necessary.
carts.
File: Two men, the front-rank man and the corresponding man of the rear rank. The front-rank man is the file leader. A file which has no rear-rank man is a blank fde. The term file applies also to a single man in a single-rank formation.
File closers: Such officers and noncommissioned officers of a company as are posted in rear of tlie line; for convenience, all men posted in the lino of file closers.
the right time.
Fire discipline: That condition resulting from training and practice v.iiich insures an orderly and efficient working of the personnel in the delivery of fire.
battle.
Front: The space, in v,-idth, occupied by an element, either in line or in column. The front of a man is assumed to be 22 inches. Front also denotes the direction of the enemy.
Head: The leading element of a column.
Horse length: A term of measurement. For convenience in estimating space a horse length is considered as 3 yards ; by actual measurement it is about S feet. — — —
, Indirect fire: There are two kinds of indirect fire:
First. When the target is visible but indistinct. In this case an ojaxiliary aiming mark is selected and the sight so corrected that the cone ofTTrewIirstrike the target.
Inferral: Space between elements of the same line. The interval between men in ranks is 4 inches and is measured from elbow to elbow. Between companies, squads, etc., it is measured from the left elbow of the left man or guide of the group on the right to the right elbow of the ris:ht man or guide of the group en the left.
is called a line of columns.
Machine guns (machine gun, heavy type) : A-Weap_on._firing nfie ammunition, aiitomatijcajly. It is provided with a stable mount, suitable mechanism' for controlling the motion of the barrel in elevating^ and azimuth, and is capable of sustained firing. i^.a dsi-f'lt'.--ri.
Mask (obstruction) : At] obiect, or a feature of the terrain, which prevents the rjunner from seeing the target. Friendly troops which prevent firing on a target.
movements.
Position in readiness: In .attajck, is a position in which the troo])s are ready to move to The "attack but are held until more accurate information of the enemy may be secured.
Tlie order in which the daily work is taken up can not be precisely prescribed. The following is suggested as a logical arrangement. Variations will suggest th/emselves to the instructor during the course of instruction. The main point is to have the instruction progressive with as little loss of time as possible In passing from one subject to another.
SpeciGltsts. — All men of machine-gun companies must thoroughly understand the mechanics and the service of the gun. so that they may be readily interchanged and the fire of the gun may not be interrupted by casualties. To this end all specialists attend, during the first two weeks, the drills of the gun squads in the forenoon, during the second two weeks in the afternoon, and during such other hours as they are not receiving instruction in their special duties. The latter are given in detail under heading " Specialists."
1. A Drill Regulation prescribes fixed movements and gives the basic principles vrhich govern the instruction and training necessary for the maneuvering of troops in peace and war. Instruction is imparted by means of explanations, lectures, fixed drills, or ceremonies, and by field and combat exercises.
2. The object of fixed movements (drills and ceremonies) is to teach a methodical and systematic nmnner in the performance of duty and to insure prompt obedience to commands and orders. Therefore, all drills should be cxecuteil with great attention to detail.
of second nature.
3. Field and combat exercises are for the purpose of illustrating the application of. given principles to concrete cases in the field. In these exercises assumed situations are employed, each exercise being conducted as it v\-ould be under the actual war conditions assumed, and concluded with a discussion on the ground of the exercises and principles involved. These exercises serve as a guide as to the best way of dealing with the usual problems M'hich may arise. But every problem which arises has its own best solution, and this solution must be evolved by the officer on the spot. His success will depend upon the extent to whicli he has prepared himself by previous thought and study and by previous practice in the solution of similar problems.
^^^^^^T-'TT^iTructioii iu peace must tlierefore be conducted with a view, first, of drilling the personnel thoroughly in their. habitual duties ; second, of affording otiicers and men practice and experience in dealing with the situations and difficulties apt. to arise in canipaign.
In order that this instruction will follow a definite and logical plan unit commanders should prepare weekly or monthly programs of instruction for their organization.
5. It is essential that the machine-gun officers possess a certain amount of mechanical ability, be resourceful, have plenty of initiative, be thoroughly familiar with the Infantry Drill and Field Service Regulations, and understand the application of combat principles to concrete cases on the battle field.
6. Officers rshould be trained to tliink quickly and logically and to assume responsibilities unhesitatingly. Errors of judgment should always be pointed out by the proper commanders, but such errors should not be criticized harshly, as such criticism causes timidity and consequent inaction, which are generally more productive of harm than is misdirected zeal.
7. It is the duty of all machine-gun commanders to impart instruction in accordance with the principles announced herein. The means employed should conform to the spirit of these regulations, but in the application of given principles to the solution of practical problems the methods prescribed are to be taken as guides only. Great latitude should be allowed in adapting these methods to the peculiar conditions of different cases, and subordinates should be encouraged in every way possible to exercise their skill and ingenuity in solving the problems which present themselves in service.
On the one hand, uniformity of mechanisms and commands is requisite, in order that the efficiency of instructed personnel may be uninterrupted, due to the differing opinions of changing unit commanders, and that reserves returning to the ranks may fulfill important duties from the beginning of their renewed serviceT i>n the other hand, no progress toward improved metliods^is possible*\viThout study and-tggtTrf-yitg^jestgfl (^TnTfTgig^' nntt* variations.
To secure the ol)jects first mentioned the methods, mechanisms, and commands prescribed herein will be habitually practiced. To develop ideas regarding improvements of materiel and methods officers vrill be encouraged to investigate, to develop and to report upon suggestions from any source for the improvement of efficiency, with a view to iheir adoption by the proper authority. But such investigations vrill not be permitted to interfere with proficiency in prescribed methods.
8. A progressive order should be followed in all instruction. The annual course of instruction should commence with the smallest unit and proceed to the larger ones in succession, culminating in the field maneuvers.
9. The efficiency of nn instructor is measured not only by his knowledge of his subject but also by his ability to hold the..attention of those whojn he is endeavoring to instruct. When the men lo.se intej-est and their attention wanders, continuation of the exercise is useless. Hence short and frequent drills arc better tJian long ones, and effort must he made to vary the exercises so as to avaid monotony.
10. The instructor maintains a military bearing and, by a quiet, firm demeanor, sets a proper example to the men. Faults are corrected gradually, without nagging or shouting.
command.
12. Thorough training of the individual soldier is the basis of efficiency. Great precision and attention to detail are essential in this instruction in order that the soldier may acquire that habit of implicit obedience to orders and of accurate performance of his individual duties ivhich is indispensable in combined training.
13. If nil the individuals of a company, including the officers, are tliorouglily trained, a comparatively short period of work in formal company drills, occupation of positions, marches, etc.. v.ith tlie company as a vrhole will suffice to produce an efficient oi-ganization for field service. On the other hand, no amount of drill of ;) c-ompany as a wholo is likely to nroduce an ethcient nruaniziiijcu if its meml)ers are not thoroughly instructed aj
14. Iiistructiou of the gun squad as a whole will not be taken up to tlie exclusion of individual training until the men are thoroughly proficient in the nomenclature and operation of all those parts of the guns, instruments, and other materiel which the men are called upon to handle in actual firing.
It will often be the case that sections and platoons will be detached from their companies and required to act upon their own resources. It is therefore important that special emphasis he laid vpon the instruction of sections and platoons as independent iniits.
15. So far as concerns the enlisted personnel, the most important element of a company's efficiency on the battle field is its fire discipline. The basis of good fire discipline, as of all other matters, is thorough individual instruction, and it can be secured and maintained only by constant and vigorous drills and other exercises. To this end gam squads will be given daily such exercises as will serve to fix their attention and cultivate their dexterity.
neither men nor animals will be idle.
17. Guns, carts, harness, and other materiel will be properly cleaned, put in order, and inspected by an officer as soon as practicable after each drill or exercise. When stables are held after drill, such men as may be needed vvdll be detailed to clean and place the materiel in proper order.
18. Both morning and afternoon hours will be utilized for instruction, sufficient time being allowed for the police of barracks, stables, and grounds and for the care of the personal equipments and effects of thr» men. All work should normally be done under the immediate direction of noncommissioned officers and under the supervision of officers.
Practical understanding: of the functions of all parts of the materiel. In addition, company officers must be able to dismount and to assemble each part of the mechanism without reference to handbooks and without assistance other than the necessary labor, and to perform with skill all the duties required in the qualitlcation of crunners.
Thorou5i-h kuowled,cre of animals under the saddle and in draft ; how best to ride, control, and manage them in order to conserve their strength ; how to train, care for, and condition them in order to secure obedience, handiness, and endurance.
21. Commands are employed in drill at attention. Otherwise, either a command, sicDiof, or order is employed, as best suits the occasion, or one may be used in conjunction with another.
22. Signals should be freely used in instruction, in order that officers and men may readily know them. In making signals the saber, rifio, pistol, or headdress may be held in the hand.
23. r)fiicers and men fix their attention at the first word of command, the first note of the bugle or whistle, or the first motion of the signal. A signal includes both the preparatory command and the command of execution ; the movement commences as soon as the signal is understood, unless otherwise prescribed.
24. Except in movements executed at attention, commanders or leaders of subdivisions repeat orders, commands, or signals whenever such repetition is <leemed necessary to insure prompt and correct execution.
section leaders, guides, and buglers are equipped with whistles.
The major and his staff will use a whistle of distinctive tone : the captain and company buglers, a second whislle of distinctive tone; and platoon and section leaders, a third whistle of distinctive tone.
voice inadequate.
Before or during an engagement special signals may be agreed upon to facilitate the solution of such special difficulties as the particular situation is likely to develop, but it must be remembered that simplicity and certainty are indispensable qualities of a signal.
OEDEKS.
26. In these regulations an order embraces instruction or directions given orally or in writing in terms suited to the particular occasion and not prescribed herein.
27. In action, the preliminary disposition of machine-gun units and their subsequent control is by means of orders or instructions issued verbally on the ground.
If practicable, the subordinate leaders may be assembled at a convenient place from vvhich the situation and plan can be explained. Clear and concise instructions are given as to the part that each unit is to take in the combat.
28. Orders should be simple and convey definite ideas. Vvhen issuing orders a commander does not encroach upon the functions of a subordinate by prescribing details of execution unless it bo necessary.
The commander prescribes what is to be done, the details of execution being left to the subordinate. It is only by constant study and practice that a commander becomes proficient in issuing simple verbal orders. Frequently a drill regulation command will be the simplest means of conveying the will of the connnander to the troops. When this is so, the drill regulation command should be used.
concerned.
The preparatory command should be given at such interval oi time before the command of execution as to admit of bein^r prop erly understood ; the command of execution should be given at the instant the movement is to connnence.
proportioned to the number of men for whom it is Intended.
Each preparatory command is enunciated distinctlv. with a rising inflection at the end, and in such manner that' the command of execution may be more energetic.
The command of execution is firm in. tone and brief.
31. Majors and commanders of units smaller than a ))attalion repeat such commands of their superiors as are to be executed by their units, facing their units for that purpose. The battalion is the largest unit that executes a movement at the command of execution of its commander.
practice firing.
Cdniuicncc firing/: Ofiicers charged with fire direction and control open fire as soon as practicable. When given to gun squads the signal is equivalent to Fike at Will.
WHISTLE SIGNALS.
34. Attention to orders: A short blast of the whistle. This signal is used on the march or in combat when necessary to fix the attention of troops, or their commanders or leaders, preparatory to giving commands, orders, or signals.
When the guns are firing, each squad leader suspends firing find fixes his attention at a sJiort blast of his platoon or section leader's whistle. The subsequent commands or signals are [repeated and enforced by the squad leader. If a squad leader's lattention is attracted by a whistle other than that of his platoon lor section leader, or if there are no orders or commands to 'Convey to his squail, his gun resumes firing at once. I Suspend Firing : A long blast of the v/histle.
' 35. The following arm signals are prescribed. In making •signals either arm may be used. Officers who receive signals jon the firing line " repeat back " at once to prevent misunder'standing.
times.
Squads right, Maech : Raise the arm laterally until horizontal ; carry it to a vertical position above the head and swing it several times between the vertical and horizontal pt>sitions.
Squads left, Maech : Raise the arm laterally until horizontal ; carry it downward to the side and swing it several times between the downward and horizontal positions.
Squads right ahout. Maech (if dismounted), or To the rear, Maech (if mounted) : Extend the arm vertically above the head ; carry it laterally dowmvard to the side and sv/ing it several times between the vertical and downvrard positions.
To change direction, or column right (left). Maech : The hand on the side tov/ard which the change of direction is to be made is carried across the body to the opposite shoulder, forearm horizontal ; then swing in a horizontal plane, arm extended, pointing in the new direction.
zontal.
^l.s- skirmishers, guide center, Maech: Raise both arms laterally until horizontal ; swing both simultaneously upward until vertical and return to the horizontal ; repeat several times.
As skirmishers, guide right {left), Maech: Raise both arms laterally until horizontal ; hold the arm on the side of the guide steadily in the horizontal position ; sv\'ing the other upward until vertical and return it to the horizontal ; repeat several times.
Assemble. Maech: Raise the arm vertically to its full extent and describe horizontal circles. (If Action has been given, at this signal the carts rejoin the "Firing Company.")
Riglit {left) into line: Signal a change of direction to the right (left), followed by describing small circles with the hand while the arm is extended to the right (left).
The signals jjlafrjon, section, and squad are intended primarily for connnunicatiou between the captain, platoon, section, and squad leaders. The signal platoon, section, or squad indicates that the platoon commander is to cause the signal shown to be executed by platoon, section, or squad.
Range or change clcration: To announce range extend the arm toward the leaders or men for whom the signal is intended, fist closed ; by keeping the fist closed battle sight is indicated ; by opening and closing the fist, expose thumb and fingers to a number equal to the hundreds of yards ; to add 50 yards describe a short horizontal line with the forefinger. To change elevation the fire controller indicates the new range. The fire observer indicates the amount of increase or decrease by pointing upward for increase, downward for decrease, and exposing the number of fingers.
What range arc you using? or What is the range? Extend the arms toward the person addressed, one hand open, palm to the front, resting on the other hand, fist closed.
front.
Distributed or traveising fiire: Extend arm to the front, palm to the left, and wave the hand up and down with a chopping motion, at the same time moving the hand and arm from right to left, or left to right, as it is desired that the fire be distrii3uted.
Searching fire, mils up: Extend arm to the front, describe a vertical circle in front of the body with the arm extended. Indicate mils as in Up mils.
scribe a vertical circle in front of the body. Indicate mils.
To siring cone of fire to the right or left: Extend the arm in full length to the front, palm to the right (left) ; swing the arm to right (left), and point in the direction of the new target.
Up mils: Extend the arm downward, with palm to the
front, and wave upward with a full swing of the arm. Indicate number of mils by thrusting closed fi.st to the front once for each D mils, and upward once for each single mil. Thus, for 4 mils thrust upv.-ard four times ; for G mils thrftst to the front once and upward once.
To left mils: Same as above, substituting left for right.
37, For communication between the firing line and the reserve or commander in the rear, the subjoined signals are prescribed and should be memorized. In the absence of signal flags, the headdress or other substitute may be used. In transmission of signals their concealment from the enemy's view should be insured.
38. For convenience in designation herein, the terms dismounted find mounted are used. The organization is considered mounted when tlie animal transportation prescribed as part of tlie equipment of the organization is present. It is dismounted when the individual mounted men are dismounted and none of the animal transportation is present.
39. Cross references to paragraphs herein are shown thus : (ST), the number in parentheses calling attention to paragraph number 87 of these regulations.
40. Movements that may be executed toward either flank are explained as toward but one flank, it being necessary to substitute the word '• left " for " right, " and the reverse, "to have the explanation of the corresponding movement tov\'ard the other iiank. The commands are given for the execution of the movements toward either flank. The substituted word of the command is placed within parentheses.
41. Any movement may be executed either from the halt or when marching, unless otherwise prescribed. If at- a halt, the command for movements involving marching need not be prefaced by fonrard. as: 1. CoUcnni right (left). 2. Maech.
double time precedes the command of execution.
43. In successive movements executed in double time the leading or base unit marches in quiel- time when not otherwise prescribed: the other units march in double time to their places in the formation ordered and then conform to the gait of the leading or base unit. If marching in double time, the command double time is omitted. The leading or base unit marches in quiek time, the other units continue at double time to their places in the formation ordered, and then conform to the gait of the leading or base unit.
44. To hasten the execution of a movement begun in quick time, the command : 1. Double time, 2. Maech. is given. The leading or base unit continues to march in quick time, or re-
mains at a halt if already halted ; the other units complete the execution of the movement in double time and then conform to the sait of the leading or base unit.
45. To stay the execution of a movement when marching, for the correction of errors, the command : 1. In place. 2. Halt, is given. All halt and stand fast, v.'ithout changing the position of the pieces. To resume the movement the command : 1. Resume, 2. Makch, is given.
46. To revoke a preparatory command, or, being at a halt, to begin anew a movement improperly begun, the command : As You Weke, is given, at which the movement ceases and the former position is resumed.
47. Unless othervvise announced, the guide of a company, or subdivision of a company, in line is right; of a battalion in line or line of subdivisions or of a deployed line, center; of a rank in column of squads, toward the side of the gTiide of the company.
48. The turn on the moving pivot is used by subdivisions of a column in executing changes of direction. Elements other than the base unit, vshen mounted, move at a double time.
49. Partial changes of direction may be executed :
By interpolating in the preparatory command the word half, as Column half right (left), or Right (left) half turn. A change of direction of 45 degrees is executed.
By the command: Incline to the Right (Left), the guide or guiding element moves in the indicated direction and the remainder of the command conforms. This m.ovement effects slight changes of direction.
50. The "designations, line of sections (line of platoons ), (line of companies), refer to the formations in which the sections, each in column of squads, are in line.
line with an interval of about 10 yards between squads.
In coluinn of subdivisions the guide of the leading subdivision is charged with the step and direction ; the guides in rear preserve the trace, step, and distance.
51. The squad, the section, the platoon, the company, and the battalion, both mounted and dismounted, execute the rests, eyes right or left, the facings, the salutes, march in quick and double time, mark time, execute the half step, side step, back step, and change step in the same manner and by the same commands as given in the school of the soldier (GO). The halt is executed (82) by substituting the designation of the unit, as: 1. Battalion, 2. Halt.
52. The battalion, company, platoon, and section, all resume attention, oblique, resume the direct march, and preserve alignment, and in addition the battalion and the company dismounted take intervals and distances and assemble in the some manner and by the same commands, substituting in the command the words " section,"' " platoon.*' *' company. "" or " battalion " for " squad." as given for the squad dismounted.
The same rule applies to detachments, details, etc.
53. To insure uniformity of interval betv.-een files when falling in. and in alignments, each man places the palm of the left hand upon tlie hip, fingers pointing downward. In the first case the hand is dropped by the side when the next man on the left has his interval; in the second case, at the command Front.
54. The posts of officers, noncommissioned officers, etc.. in the various formations of the company and battalion are shown in plates imder the various headings. For the position of the machine-gun company in the Infantry regiment see the Infantry Drill Regulations.
In all changes from one formation to another involving a change of post on the part of any of these, posts are promptly taken by the most convenient route as soon as practicable after the command of execution for the movement ; oflicers and noncommissioned ofiicers who have prescribed duties in connection with the movement ordered take their new posts when such duties are completed.
the ranks.
55. The staff of an officer forms in single rank 3 paces in rear of him, the right of the rank extending 1 pace to the right of a point directly in rear of him. Members of the staff are arranged in order from right to left as follows: General staff officers, adjutant, aids, other staff officers, arranged in each classification in order of rank, the senior on the right. The Hag of a general officer and the orderlies are 3 paces in rear of the staff", the Hag on the right. When necessary to reduce the front of the staff and orderlies each line executes twos right or fours right, and folio vrs the commander.
and orderlies do not change position.
57. For ceremonies, such of the noncommissioned staff" officers as are dismounted are formed 5 paces in rear of the color, in order of rank from right to left. In column of squads they march as file closers.
58. Other than for ceremonies, noncommissioned staff officers and orderlies accompany their immediate chiefs unless otherwise directed. If mounted, the noncommissioned staff" officers are ordinarily posted on the right or at the head of the orderlies.
59. In all formations and movements a noncommissioned officer commanding a platoon or company takes tlie same post as an officer in a like situation.
60. The instructor explains briefly each movement, first executing it himself, if practicable. He requires the recruits to take the proper positions unassisted and does not touch them for the purpose of correcting them, except v/hen they are unable to correct themselves. He avoids keeping them too long at the
uniformity.
61. In order that all may advance as rapidly as their abilities permit, the recruits are grouped according to proficiency as instruction progresses. Those who lack aptitude and quickness are separated from the others and placed under experienced drill masters.
At the command fall out the men may leave the ranks, but are required to remain in the immediate vicinity. They resume their former places at attention at the command Fall In.
constraint, iu front of the center of the body, fingers joined, left hand uppermost, left thnmb ehisped ])y the tliumb and forefinger of the right iiand ; preserve silence and steadiness of position.
Raise slightly the left heel and right toe; face to the right, turning on the right heel, assisted by a slight pressure on the ball of the left foot ; place the left foot by the side of the right. Left face is executed on the left heel in the corresponding manner.
" To face in marching " and advance turn on the ball of either foot and step off with the other foot in the new line of direction ; to face in marching without gaining ground in the new direction turn on the ball of either foot and mark time.
69. To the rear: 1. About, 2. Face.
Carry the toe of the right foot about a half-foot length to the rear and slightly to the left of the left heel, without changing the position of the left foot ; face to the rear, turning to the right on the left heel and right toe ; place the right heel by the side of the left.
70. 1. Hand. 2. Salute.
Raise the right hand smartly till the tip of the forefinger touches the lovv'er part of the headdress above the right eye, thumb and fingers extended and joined, palm to the left, forearm inclined at about 45 degrees, hand and wrist straight; at the
cadence is at the rate of ISO steps per minute.
The instructor, when necessary, indicates the cadence of the step by calling one, two, three, four, or left, rigid, the instant the left and right foot, respectively, should be planted.
73. All steps and marchings and movements involving march are executed in quick time unless the squad be marching in (louhJc time, or double time should be added to the command; in the latter case double time is added to the preparatory command. Example: 1. Squad right, double tt)iic, 2. Makcu. (School of the squad.)
right leg. left knee straight.
At the command march, move the left foot smartly straight forward 30 inches from tlie right, sole near the ground, and plant it without shock ; next, in like manner, advance the right foot and plant it as above ; continue the march. The arms swing naturally.
If at a halt, at the first command, shift the weight of the body to the right leg. At the command march, raise the forearms, fingers closed, to a horizontal position along the waistline: take up an easy run witii the step and cadence of double time, allovring a natural swinging motion to the arms.
77. Being in march : 1. IJarlc time, 2. March,
At the command march, given as either foot strikes the ground, advance and plant the other foot ; bring up the foot in rear and continue the cadence by alternately raising each foot about 2 inches and planting it on line v\-ith the other.
March,
Carry and plant the right foot 15 inches to the right, bring the left foot beside it, and continue the movement in the cadence of quick time. The side step is used for short distances only and is not executed in double time.
2. Halt.
At the command halt, given as either foot strikes the ground, plant the other foot as in marchin.s; ; raise and place the tirst foot by the side of the other. If in double time, drop the hands by the sides.
At the command march, given as the right foot strikes the ground, advance and plant the left foot ; turn to the right about on the balls of both feet and immediately step off with the left foot.
At the command march, given as the right foot strikes the ground, advance and plant the left foot; plant the toe of the right foot near the heel of the left and step off with the left foot.
tion, discipline, control, and order.
87. The gun squad proper consists of a corporal and 8 privates. However, for instructional purposes the men are grouped into squads of from 3 to 11 men each.
The movements in the school of the squad are designed to make the squad a fixed unit and to facilitate the control and movement of the company. If the number of men grouped is more than 3 and less than 12 they are formed as a squad of 4 files, the excess above 8 being posted as file closers. If the number grouped is greater than 11, two or more squads are formed and the group is terined a section.
For the instruction of recruits these rules may be modified.
88. The corporal is the squad leader, and when absent is replaced by a designated private. If no private is designated the senior in length of service acts as leader.
the file closers.
Vvheu the corporal leaves the ranks to lead his squad, his rear-rank man steps into the front rank, and the file remains blank until the corporal returns to his place in ranks, when his rear-rank man steps back into the rear rank.
integrity of these squads.
Men are taught the necessity of remaining with the squad to which they l^elong, and in case it is broken up or they become separated therefrom to attach themselves to the nearest squad and section leaders, whether these ])e of their own or another organization.
The men assemble at attention, and are arranged by the corporal in double rank, as nearly as practicable in order of height from right to left, each man dropping his left hand as soon as the man on his left hfis his interval. The rear rank forms with distance of 40 inches.
The instructor then commands : Count off.
At this conmiand all except the right file exeentes eyes right, and. beginning on the right, the men in eacli rank count one, tico, three, four; each man turns his head and eyes to the front as he counts.
At the connnand dress, all men place the left hand upon the hip (whether dressing to the right or left) ; each man. except the base file, when on or near the new line executes eyes right, and, taking steps of 2 or 3 inches, places himself so that his riglit arm rests lightly against the elbow of the man on his right, and so that his eyes and shoulders are in line with those of tlie men on his right ; the rear-rank men, in addition, cover in file.
The instructor verifies the alignment of both ranks from the rigiit fiank and orders up or back sucli men as may be in rear or in advance of the line; only the men designated move.
directions.
Wh; iiever rhe position of tlie base file or files necessitates a considej-able movement by the squad, such movement will be executed by marclung ro tiie front or oblique, to the flank or backward, as the case may be, without other command, and at the trail.
the opposite direction ; tliey recover intervals, if lost, by .crradually opening out or closing in ; they recover alignment by slightly lengthening or shortening the step ; the rear-rank men cover their file leaders at 40 inches. ,
In double rank, the front-rank man on the right, or designated flank, conducts the march ; when marching faced to the flank, the leading man of the front rank is the guide.
At the second command the rear-rank men march backward 4 steps and halt ; at the command march all face to the right and the leading man of each rank steps off ; the other men step off in succession, each following the preceding man at 4 paces, rearrank men marching abreast of their file leaders.
The front-rank man on the right stands fast, the rear-rank man on the rigiit closes to 40 inches. The other nien face to the right, close by the shortest line, and face to the front.
1. 2, 3, and 4 of the rear rank, in the order named, move straight to the front, each stepping off so as to follow the preceding man at four paces. The command halt is given when all have their distances.
THE OBLIQUE MAECH.
98. For the instruction of recruits, the squad being in column or correctly aligned, the instructor causes the squad to face half right or half left, points out to the men their relative positions, and explains that these are to be maiixtained in the oblique march.
Each man steps off in a direction 45 degrees to the right of his original front. He preserves his relative position, keeping his shoulders parallel to those of the guide (the man on the right front of the line or column), and so regulates his steps that the ranks remain parallel to their original front.
The movement is executed by each rank successively and on the same ground. At the second command, the pivot man of the front rank faces to the right in marching and takes the half step : the other men of the front rank oblique to the right until opposite their places in line, then execute a second right oblique and take the half step on arriving abreast of the pivot man. All glance toward the marching flank while at half step and take the full step without command as the last man arrives on the line.
Right (left) half turn is executed in a similar manner. The pivot man makes a half change of direction to the right and the other men make quarter changes in obliquing.
rank men oljlique to the right, place themselves abreast of the pivot and mark time. In the rear rank the third man from the right, followed in column by the second and first, moves straight to the front until in roar of his front-rank man, when all face to the right in marching and mark time ; the other number of the rear rank moves straight to the front four paces and places himself abreast of the man on his right. Men on the new line glance toward the marching flank wliile marking time and, as the last man arrives on the line, both ranks execute foricard, march, without command.
The third command is given immediately after the second. The turn is executed as prescribed in the preceding paragraph, except that all men, on arriving at the new line, mark time until the fourth command is given, when all halt. The fourth command should be given as the last man arrives on the line.
At the second command, the front rank tvs'ice executes squad right, initiating the second squad right v/hen the man on the marching Hank has arrived abreast of the rank. In the rear rank the third man from the right, followed by the second and first in column, moves straight to the front until on the prolongation of the line to be occupied by the rear rank ; changes direction to the right ; moves in the new direction until in rear of his front-rank man, when all face to the right in marching, mark time, and glance toward the marching flank. The fourth man marches on the left of the third to his new position ; as he arrives on the line both ranks execute forward, march, Avithout command.
The third conmiand is given immediately after the second. The turn is executed as prescribed in the preceding paragraph, except that all men, on arriving on the new line, mark time until the fourth command is given, when all halt. The fourth command should be given as the last man arrives on the line.
mands : Follow Me.
If in line or skirmish line, Xo. 2 of the front rank follows in the trace of the corporal at about 3 paces ; the other men conform to the movements of No. 2, guiding on him and maintaining their relative positions.
2. March.
The corporal places himself in front of the squad, if not already there. Moving at a run, the men place themselves abreast of the corporal at half-pace intervals, Xos. 1 and 2 on his right. Nos. 3 and 4 on his left, rear-rank men on the right of their file leaders, extra men on the left of No. 4 ; all men conform to the corporal's gait.
^Yhen tlie squad is acting alone, skirmish line is similarly formed on No. 2 of the front rank, Vvdio stands fast or continues the march, as the case may be ; the corporal places himself in front of the squad when advancing and in rear when halted.
front rank is the guide.
107. The normal interval beiveen skirmishers is one-half pace, resulting practically in one man per yard of front. The front of a squad thus deployed as skirmishers is about 10 paces.
TO INCREASE OR DIMINISH IXTEP.VALS.
108. If assembled, and it is desired to deploy at greater than the normal interval ; or if deployed, and it is desired to increase or decrease the interval: 1. As skirmishers (so many) paces, 2. March.
110. If standing: Kxeel.
Half face to the right ; carry the right toe about 1 foot to the left rear of the left heel ; kneel on right knee, sitting as nearly as possible on the right heel ; left forearm across the left thigh, right hand resting on right leg.
handling: the company.
116. The instruction described for the company dismounted is applicable, with obvious modifications, to the instruction of any number of platoons, sections, or squads.
in detail in Tables of Organization.
118. For technical and tactical purposes, the enlisted personnel of the comi^any is assigned to sections and platoons. The sections are organized to meet the special conditions of service which they are called upon to perform. A gun section consists of 1 sergeant, who is the section leader, 2 section agents, and 2 gun squads.
A platoon consists of a lieutenant, a range taker, 3 platoon agents, and 2 gun sections. One of the company mechanics is assigned to each platoon in the field.
119. The company is divided into 9 sections, the first 6 sections being gun sections. The train, commanded by the train lieutenant, consists of the seventh and eighth sections. The seventh section is the combat train section and consists of two 4-nnile wagons, the kitchen wagon, and two spare gun carts, v\-ith the stable sergeant in charge of the ammunition v>agons and the mess sergeant in charge of the kitchen wagon ; the eighth section consists of the supply wagon, the water and ration carts, and is commanded by the supply sergeant. The nintli section is the company commander's detail and consists of the company agents, signalmen, and scouts commanded ])y the signal corporal. (See Pis. I to VI, inclusive.)
120. The company dismounted is formed in double rank with the platoons arranged from right to left in the order of their permanent numbers, except that the ninth section, plus the platoon and section agents, forms on the right of the first platoon and is connnanded by the reconnaissance officer. The members of the seventh and eighth sections in the order named habitually take their places in the line of file closers.
ISl. The posts of ofncers and noncommissioned officers are as shown in Plate I. The company range taker is the right guide of the company ; the phitoou range takers are the phitoon guides; the platoon range taker of the left platoon is also the left guide of the company.
In platoon movements the post of the platoon guide is at the head of the platoon if the platoon is in column, and on the guide flank if in line. Tlie guides of a column of squads place themselves on the flank opj)osite the file chasers.
122. In taking intervals and distances, unless otherwise directed, the right and left guides, at the first command, place tliemselves in the line of file closers, face to the flank, and each st(^ps off with the file nearest him. In asscmblinf/ the guides and file closers resume tlieir positions in line.
123. In movements executed simultaneously by platoons or sections (as platoons or sections right, or platoons or sections column rirjM), platoon leaders or section leaders repeat the preparatory command {platoon or section right, etc.) apjilicable to their respective platoons or sections. The command of exe-. cution is given by the captains only.
124. At the sounding of the assembly the first sergeant takes position G paces in front of wliere the center of the company is to be. faces it, draws saber, and commands : Fall In.
the center of tlie company will be 6 paces from and opposite the first ser.ueant : the squads and sections form in thoir proper places on the left of the ri.dit uuide. superintended by the section and squad leaders, who then take their posts.
The salutes of the section leaders is not returned by the first sergeant. The first sergeant notes the presence or absence of the men not assigned to sections, then faces about, salutes the captain, and reports: Sir, all present or accounted for, or the names (^f the unauthorized absentees, and. without command, takes his post. r>Ien who are known to be absent by proper authority are not reported absent by the section leaders.
The captain places himself 12 paces in front of the center of and facing the company in time to receive the report of the first sergeant, whose salute he returns, and then draws saber.
TO DISMISS THE COMPANY.
125. Being in line at a halt, the captain directs the first sergeant: Dismiss the companii. The ofiicers fall out; the first sergeant places himseli'. faced to the front. 3 paces to the front and 2 paces from the nearest flank of the company, salutes, faces toward opposite flank of the company, and commands : 1. Inspection, 2. Akms, 3. Port, 4. Aems, 5. Dismissed.
ALIGNMENTS.
126. The alignments are executed as prescribed in the school of the squad, the guide being established instead of the flank file. The rear-rank man of the flank file keeps his head and eyes to the front and covers nis h\e leaders.
At each alignment the captain places himself in prolongation of the line. 2 paces from and facing the tlank toward which the dress is made, verifies the alignment, and commands : Fkont.
127. At dismounted formations, if a squad contains less than 6 men, it is increased to that number by transfers from other squads, or it is broken up and its members assigned to other squads or posted in the line of file closers.
128. Being in line at a halt: 1. Open ranks, 2. March.
At the command marcli the front rank executes right dress; the rear rank and the file closers march backward four steps, halt, and execute light dress; the lieutenants pass around their respective Hanks and take posts, facing to the front 3 paces in front of their respective platoons ; the train lieutenant takes post 1 pace to the left of the reconnaissance officer. The captain aligns the front rank, the rear rank, and file closers, takes post 3 paces in front of the right guide, facing to the left, and commands : Front.
At the command march, the lieutenants resume their posts in the line of tile closers ; the rear rank closes to 40 inches, each man covering his file leader ; the file closers close to 2 paces from the rear rank ; the captain takes his post.
soon as it has completed the squad riglit.
In the second case, at the command march, the right squad marches forward; the remainder of the company executes the squads right (101) column left (131) on the same ground as the right squad, and 1'ollows the right squad. The right squad in moving olT takes four short steps and then the full step.
133. Being in column of squads, to form line to the flank : 1. Squads right (left), 2. Maech, 3. Guide eight (left) ; or 1. Squads right (left), 2. Maech, 3. Company, 4. Halt.
Halt, 5. Feont.
At the first command the corporal of the leading squad commands: Right turn. The corporals of the other squads command : Forward, if at a halt. At the second command the leading squad turns to the right on a moving pivot. The command hrdt is given when the leading squad has advanced the desired distance in the new direction; it halts; its corporal then commands: Right {left) dress.
The squads in rear continue to march straight to the front ; ouch, when opposite the right of its place in line on the left of the preceding squad executes right turn at the command of its corporal ; each is halted on the line at the command of its cc.rporal, who then commands: Right dress. All dress on the first squad in line.
At the first command the corporals of the squads in rear of the leading one command: Right oblique. If at a halt, the corporal of the leading squad commands : Forward. At the sees ond command the leading squad moves straight forward ; the rear squads oblique as indicated. The command halt is given v.^heu the leading squad has advanced the desired distance; it halts ; its corporal then commands : Left dress. Each of the rear squads when opposite its place in line resumes the original direction at the command of its corporal ; each is halted on the line at the command of its corporal, who then commands : Left dress. All dress on the first squad in line.
TO rOEM FLANK COLUilN OF FILES FROM LINE.
136. Movements in flank column have no disciplinary value. Their use should be limited to the rare occasions necessitating a narrow front of the column. They are executed in quick time only.
ivard, 4. March.
At the second command all face to the right. At the fourth command all take the full step. Individuals not in the two ranks move so as to preserve the relative positions they had in line.
The corporal commands the squad. Xo. 1 is the gunner, Xo. 2 is the loader, Xos. 3 and 4 are ammunition men, Xos. o and 6 are spare men and are in charge of the belt-filling station, Nos. 7 and 8 are drivers.
141. The object of the preliminary drills is to insure individual expertness aud clean-cut movements in handling the gun by night as well as by day ; therefore, night drills or drills with the men blindfolded must be held until all movements are executed smoothly and without false motions.
target.
3. Tripod on the left, clamps tight, strap around trail and buckled, traversing clamp sufficiently tight to prevent the tripod head from coming out of the socket and to prevent it from swinging around when the tripod is being carried, legs to the rear, tripod head over trail.
4. Gun on the right, muzzle pointing to the front, stem in, bottom plate slide closed, covers locked, handle block pin screwed in. T head pointing straight up and down, rear sight leaf lowered with slide set at 600, barrel disk tight and sleeve secured with locking pin. trigger pushed and mainspring released, heads in traversing handles screwed home, water jacket filled (see note below), oil reservoirs filled.
TO FORM THE GUN SQUAD.
144. The instructor indicates the place of formation, about 8 paces in rear of the gun, and commands : Fall In. At this command the squad assembles as in " The school of the squad " (91). The instructor then commands: Call Off. Commencing on the right the men call off alternately, front and rear rank, " One," " Two," " Three," " Four," and so on.
145. Posts. At the command Posts, No, 1 wi-11 repeat the order ; and all men move at double time to positions as folhjws : No. 1 will pass behind the gun and fall in on the left of the tripod; No. 2 will fall in on the right of the gun; No. 3 will fall in on the left of the ammunition box ; Nos. 4, 5, and 6 will fall in about 5 paces in rear of No. 3, No. 4 being on the right.
posed.
No. 2 vrill attend to the points mentioned in paragraph 143. section 4, and will inspect the tool box, making certain that the contents are complete. (The inspection of the tool box is done twice only during the drill : once by the first Xo. 2 and once by the last No. 2. )
No. 3 will examine the belt and see that the dummies are correctly placed in the box, and v^ill then lock the box. The catch on the ammunition box will be toward the front. He will th.en report " Correct " to Xo. 2, who will report " Gun and amuumition correct " to No. 1, who in turn will report '"AH correct " (or otherwise) to the instructor.
TO MOUNT THE GUN.
147. Note. — The instructor will now bring the team to the left of the spot where the gun is to be mounted, so that they may see all movements clearly and listen to explanations. He will then act as No. 1, himself, giving and repeating the order Mount Gun, and will point out a spot which will be about 30 yards from the target where the gun is to be mounted.
On the command Mount Gun, No. 1 picks up the tripod with his right hand at the balance, steadies it with the left hand, and moves forward at a run to the designated position. He then places the tripod on the ground, unclamps the legs, swings legs to the front and clamps them in such position that the socket will be upright and at a convenient elevation. He then sits down behind the tripod and withdraws elevating pin with the right hand and the trunnion pin with the left hand. While adjusting the tripod, the following points must be attended to : The left forearm must be supported by the left thigh and the clamping handles should, if possible, both be manipulated with the right hand.
As soon as the tripod is nearly in position. No. 2 pushes the bottom plate slide to the rear, grasps the right handle block with the left hand, passes the right hand over the water jacket and lifts the gun so that the barrel will be pointing to his right, under his right arm, moves forward at a run, and takes position at the right of the tripod and facing it.
He must reach the position at the moment No. 1 is removing the elevating and trunnion pins. He places his right foot between the front legs of the tripod, kneels on the left knee, supporting the weight of the gun on the right knee. With the assistance of No. 1 he puts the gun in position, inserts the trunnion pin, and turns it down. He then removes the stem and lies down opposite the feed box of the gun, placing the belt box in position in line with the feed box.
No. 1 assists No. 2 in adjusting the gun to the tripod and inserts the elevating pin. After putting in the elevating pin No. 1 will at once level the gun, adjust the traversing clamp to see that it is moderately tight, and take the correct hold ; eyes must be directed toward the target.
No. 3 takes two ammunition boxes and places them in reach of No. 2, then returns to his original position. The catches should be to the front and the boxes must not be placed in such a position that No. 2 is likely to knock them over as he lies down. The ammunition' must be at hand by the time No. 2 is ready for it. •' ... .>
When the men have made sufficient progi'ess in the foregoing lessons, they will be exercised in combining them and coming into action. Three aiming marks will be pointed out on the landscape target by the instructor, one of which should be in the foreground, one in the middle distance, and one in the background.
The instructor will name the range and target and at the command or signal Action the gun will be mounted, loaded, and laid. As soon as No. 2 puts up his hand, the aim and sight setting will be checked, and then the various points taught in the earlier lessons will be criticized. No. 2 must not be allowed to adjust the sights. Each number must perform the duties laid down for him in the earlier lessons and the aiming marks given by the instructor must be service targets and not haystacks, windmills, or steeples.
149. xVt the command Dismount Gun, Xo. 1 removes both pins and carries the tripod back to its original position, clamps the legs and lays the tripod on the ground on the left of the gun. In folding the legs he first loosens the clamps, allowing the tripod to collapse, next seizes the tripod head with both hands, and with a sharp upward, forward, and downward movement folds up the legs. He then tightens the clamps, and, if necessary, aligns the tripod head over the trail and lies down on the left of the tripod.
No. 2 passes the ammunition box to No. 3, lifts the gun from the tripod, replaces the stem before leaving the gun position, and then double times l)ack to the original position. Before placing the gun on the ground he ^ill close the bottom plate slide and reset the sight at 600 yards.
brings back both ammunition boxes to the original position.
Note. — At the beginning of this exercise it is well to divide the action of dismounting the gun into two parts, the dismounting of the tripod being mastered first by all members of the team, after the instructor has shown how the tripod is dismounted. When all of the numbers have made reasonable progress with the tripod, the instructor will then continue the instruction in mounting the gun and dismounting the gun.
150. Efliciency having been attained under the preceding paragraphs, with the tripod in its highest position, the gun squad is then instructed in mounting the gun on hillsides, uneven trround. and in the several positions of the tripod. (Pis. 30 to 40. inclusive. :\l. G. F. M.)
and No. 2.
At the command Load, No. 1 holds the roller handle in its rearmost position with the right hand and advances his left hand to the left of the feed box, ready to grip the tag of the belt.
No. 2 opens the ammunition box. holds the end of the belt with his forefinger (right hand recommended) on the brass tag at the point where it joins the fabric, and pushes the tag of the belt through the feed^box as far as possible.
No. 1 grips the tag. then pulls the belt through the feed box as far as possible, and releases the roller handle. He again pulls the roller handle to the rear, pulling the belt to the left a second time as far as it will go, and again releases the roller handle. The gun is now loaded for automatic fire and No. 1 resumes his hold on the gun.
TO load for single shots.
153. 1. Single shots, 2. Load. At the command Load, No, 1 pulls the roller handle to its rearmost position ; No. 2 passes the tag of the belt through the feed box ; No. 1 holds the roller handle in its rearmost position with the right hand, grasps the tag of the belt with the left hand and pulls it straight through the feed box as far as it will come. He then releases the roller handle and without pulling on the belt he again pulls the roller handle to its rearmost position and releases it. The gun is now loaded for single shots : by bringing the roller handle to the rear after each shot without pulling the belt, the gun will fire single shots. To change from single shots to automatic fire at any time, it is necessary to pull the roller handle to its rearmost position, pull the belt to the left, and release the roller handle. The gun being loaded for automatic fire, single shots may be fired by first operating roller handle once without pulling belt.
TO lay the gux.
154. Note. — It is an advantage to combine the adjustment of sights with laying the gun; therefore, instruction in aiming should be given prior to instruction in laying the gun.
The tar.cret being indicated l>y tr.e instructor, the C(.unmand is iriven: 1. 'Ran^'c i.SOO yanJr;) rUjlit {left) (2) (this being tlie deflection in points of windage to the right (left), 2. At (such AN object). At the first command. Ivo. 1 raises tlie rear sight leaf (unless the range announced is less than 500 yards, when the battle sight will be used) and moves the slide until the line of sight coincides with the line on the leaf corresponding to the range ordinate. He then taps the gun over until the correct direction is obtained and elevates or depresses until the aim i' correct. Should a fairly large change in direction be nocessar\-. No. 1 will order No. 2 to loosen the clamp, swing roughly on the target, order No. 2 to tighten, and then lay accurately by tapping. It is most important that while tapping the gun or manipulating the elevating wheel, the correct hold should be maintained with the other hand. As soon as the aim is correct, he then grasps both handles, places the thumbs on the trigger, releases the safety catch, and by calling Ready, orders No. 2 to put up his hand. Care must be exercised when checking the aim to prevent the gun being moved as No. 1 moves his head to one side to allow the aim to be viewed by the instructor.
155. The gun being mounted and loaded, or assumed to be loaded: 1. Range {800) right {left) (2), (this being the deflection in points of windage to the right or left), 2. At (such an ob.ject), 3. Fixed {distrihiited, searching, ranging) fire, 4. {So manij) rounds {as 1 belt, etc.), 5. Commence Firing.
The details and methods to be used in teaching the different kinds of fire are given in the Machine-Gun Firing ?.I;inual. For definitions of the different kinds of fire see " Definitions."
At tlie first and second commands the operations prescribed in the previous paragraph are performed. The third and fourth connnands are preparatory and indicate the class of fire and th(^ number of rounds to be fired. These commands are given when necessary.
At the conunand Co>[^rENCE Firing, No. 1 instantly presses the trigger without deranging his aim and at the same time maintains a steady hold on the handles.
TO SUSPEND FIBIXG.
156. The instructor blows a long blast on his whistle, and repeats same if necessary, and commands Suspend Firing. Firing stops ; No. 1 releases the pressure on the trigger. The gun is left loaded and in a position of readiness for an instant resumption of firing. The corporal and No. 1 continue their observations of the target, the aiming point, or the place at which the target disappeared or at which it is expected to reappear.
TO CEASE FIKING.
157. At the command Cease Firing, No. 1 releases the pressure on the trigger, grasps the roller handle with right hand, and brings it to its rearmost position not less than three times, pulls the trigger, and lays down the rear sight. No. 2 grasps the upper and lower feed-box pawls with the thumb and forefinger of the left hand, presses them together, and with the right hand withdraws the belt from the feed box, replacing it in the ammunition box.
TO UNLOAD.
158. At the command Unload, No. 1 will lower the sight leaf, if it be raised, with the left hand ; at the same time he will pull the roller handle to its rearmost position and immediately allow it to fly forward, repeating this motion at least three times. He will then press the upper and bottom pawls of the feed box with the right hand, the upper pawls being pressed with the thumb and the l)ottom pawls with the finger, taking care to keep the hand clear of the entrance to the feed box. No. 2 will withdraw the belt and pack it carefully in the box ; No. 1 will then release the mainspring by pressing the trigger.
SQUAD DltlLL,
160. The gun mule and ammunition mule being hitched, as described on page ITS, the drivers take their positions at the head of the mules and remain at attention. The gun squad -falls in, facing to the front, with the center of the rear rank 3 paces to the front of the gun mule, the squad leader taking post as in the Squad Dismounted.
162. The squad leader commands: Fall In, placing himself so that the center of the rear rank of the squad will be .3 paces to the front of the gun mule. Members of the gun squad fall in at a run.
TO MARCH TO THE KEAE.
165. 1. To the rear. 2. Makch. At the command march the gun cart turns to the left about on the arc of a circle whose radius is 2 yards, followed in trace by the ammunition cart.
166. To march to the rear for a few paces: 1. Backward, 2. March. At the command march, the drivers rein back^ the mules, and the men execute backward march as in the school of the soldier.
TO OBLIQUE.
167. 1. Right oblique. 2. March. At the command march the gun and ammunition carts, respectively, execute a half turn to the right and move off in the oblique direction.
TO PREPARE rOR ACTION,
170. The command is: Action. At this command the carts, if moving, halt. The squad leader marks the place at which the gun is to be set up. No. 1 secures the gun : No. 2 the tripod ; No. 3 the water box and one ammunition box ; No. 4 the tool box. condensing device, and one ammunition box ; Nos. 5 and G secure the belt-filling machine and loose ammunition.
The Nos. 1. 2, 3, and 4, as soon as they have secured their equipment, move forward as described in paragraph 147, and, under the direction of the corporal, mount the gim.
TO REASSEMBLE THE SQUAD.
171. The command is : Assemble. At this command the gun is dismounted, the carts move up at a run to their original positions, and halt ; the squad resumes its original formation.
in Plates III and IV or in column of squads as in Plate II.
The post of the section leader when the section is in line is 3 paces in front of the center of the interval between squads. When the section is in column of squads his post is on the left of the driver of the leading mule.
The section in column of squads marches to the front, to the rear, obliques, and halts in the same manner and by the same commands as prescribed for the squad, substituting " section " for " squad."
TO CHANGE DIEECTION.
• 173. Being in column of squads: 1, Column right (left), 2. March. At the first command the leader of the leading squad commands : Right turn. The leader of the rear squad commands. Foru-ard, if at a halt.
At the second command, the leading squad turns to the right as prescribed (164). The rear squad marches squarely up to the turning point and turns on the same ground and in a similar manner to the leading squad.
turn, double time.
At the second command the right squad executes a change of direction as described in paragraph 164; the left squad executes right half turn and. when opposite its position in the new line, it again executes right haif turn, and comes up abreast of the right squad with an interval of 10 yards and takes up the quick time.
line, 2. Makch, 3. Seetion. 4. Halt, 5. Front.
At the first command the leader of the leading squad commands: Foncard : if at a halt, the leader of the squad in rear commands : Right oblique. The command liait is given when the leading squad has advanced the desired distance. It halts and its leader connnands : Left dress.
The rear squad, when opposite its place in line, resumes the original direction and is halted on the line at the command of its leader, who then commands : Left dress.
The leading squad is halted at the fourth command, and dressed to the right bj' the squad leader. The rear squad, when on the new line, halts and dresses to the right. When all are dressed the command front is given. •
In the second case, at the command march the right squad marches forward; the remaining squad executes squads right and then column left, and follows the right squad.
right.
At the second command the right squad moves forward twice squad distance, is halted and dressed to the right by its squad leader. The left squad executes squads right, and when opposite its place in the new line executes squads left, placing itself abreast of the right squad with 3 pace interval between carts. The command front is given by the section leader when the alignment is verified.
At the command march all move off. the left squad upon gaining its interval marches to the front. The base squad halts at the fourth command. The left squad when abreast of the new line is halted and dressed. The command front is given by the section leader when the alignment is verified.
2. March, 3. Froiit.
At the command march the leading squad executes left turn. advances squad distance, and halts. The remaining squads, if at a halt, move forward and, in succession, execute squads left, coming up abreast of the leading squad, and halt, with an interval of 3 paces between carts.
Stand fast.
At the command of execution the right squad executes squads right. The remaining squads, in succession from the right, execute squads right when uncovered by the squad on their right.
185. The platoon marches to the front, to the rear, obliques, and halts in the same manner, and by the same commands as prescribed for the squad mounted, substituting "platoon" for " squad."
Forward.
At the command march the leading section turns to the right ; the rear sections march squarely up to the turning point of the leading section and turn at the command of their leaders.
At the first command the leaders of the units in rear of the leading one command : Right oblique. If at a halt, the leader of the leading unit commands: Foricarcl. At the second command the leading unit moves straight forward ; the rear units oblique as indicated. The command halt is given when the leading unit has advanced the desired distance ; it halts ; its leader then commands : Left dress. Each of the rear units when opposite its place in line resumes the original direction at the command of its leader ; each is halted on the line at the command of its leader, who then commands : Left dress. All dress on the first unit in line.
Executed by each section as described in the section mounted (175). In forming tlie platoon in line, it dresses on the left squad of the left section. In forming column of sections, section leaders verify the alignment before taking their posts. The platoon leader commands: Front, when the alignments have been verified.
When front into line is executed in double time, the commands for halting and aligning are omitted, and the guide is toward the side of the first unit in line.
if at a halt.
At the second command the leading unit turns to the right. The command halt is given when the leading unit has advanced the desired distance in the new direction. When halted, its leader commands: Right dress.
The units in rear march straight to the front ; each, when opposite the right of its place in line, executes right turn at the command of its leader. Each is halted on the line at the command of its leader, who then .commands: Right dress. All dress on the first unit in line.
In the second case at the command march, the right squad marches forward ; the remainder of tlie platoon executes squads right and then column left, and follows the right squad.
195. Being in line: 1. On right squad, 2. Close, 3. Front.
At the first command, the leader of the right squad commands : Forward. The leaders of the left squads command : Squads right. At the second command the right squad moves forward twice squad distance (20 yards) and halts. The remaining squads execute squads right and, in succession, when opposite their place in the new line, squads left, placing themselves abreast of the right squad with 3-pace intervals between carts.
3. Platoon, 4. Halt.
At the first command all squad leaders, except the leader of the base squad, command : Left oblique. The leader of the base squad commands : Forioard. At the command of execution, all move off and the squads, in succession from the right, upon gaining their interval, march to the front. Only the base squad halts at the fourth command. The remaining squads, when abreast of the new line, halt.
parade by tlie first sergeant, as prescribed in paragraph 120.
After the company is formed, the first sergeant conunands : Stable Details Fall Out. At this command all section leaders and drivers fall out. Tlie senior section leader takes command, marches the details to the stables, and commands: Haeness. At this command, all drivers and section leaders fall out, and under the supervision of the respective section leaders the mules are harnessed.
When all mules are harnessed the senior section leader commands : Hitch. At the command the mules are led to the carts and hitched, and the drivers take their posts.
When the drivers and section leaders have fallen out, the first sergeant marches the company to the gun sheds .and commands : Equipment. At this command squad leaders take charge of their squads, secure all ecpiipmeiit that is to be placed
POSTS OF OFFICEES AND NONCOMMISSIONED OFFICEES.
202. The post of the company commander is 10 paces to the front of the center of the company. The post of the platoon leader is 3 paces in front of the center of his platoon. The post of the section leader is 1 pace in front of the center of the interval between squads.
203. The first sergeant takes post 5 paces in front of the center of the company and commands: Fall In — Report. At the first command, the section leaders and squads fall in, as in Plate III. At the second command, the section leaders verify tlieir sections, salute, and report, as in paragraph 124. When all have reported the first sergeant faces about, salutes the captain, and reports (124).
204. The captain places himself 10 paces in front of the center of and facing the company in time to receive the report of the first sergeanf, whose salute he returns, and then draws saber.
205. The captain directs the first sergeant: Dismiss the cornpan]). The officers fall out, the first sergeant conducts the company to the park, whei-e it is halted in close line, as shown in Plate III, and commands : Equipment. At this command the squad leaders take command of the gun squads and supervise the cleaning and replacing of all equipment.
When the equipment is removed from the carts the senior section leader commands : Uxhitch. At tliis command the mules are unhitched, under the supervision of the section leaders. The senior section leader then commands: Unharness. The mules are led to the sta])les and the harness removed. The commands unhitch ajid. unharness may be given at the same time, in which case the two duties will be performed in succession.
The harness is cleaned and the mules cared for as in paragraphs 38.S-44S. The senior section leader then forms the details, marches them to the company parade, and dismisses them.
206. The company marches to the front, to the rear, obliques, and halts, in the same manner and by the same commands as prescribed for the squad mounted, substituting " company " for " squad."
The leading unit turr,^- to the right as prescribed in paragraphs 164 and 174, The rear units march squarely up to the turning point, and turn on the same ground and in a manner similar to the leading unit.
At the first command the leaders of the units in rear of the leading one command : Right oblique. If at a halt, the leader of the leading unit commands : Forward. At the second command the leading unit moves straight forward. The rear units oblique as indicated. The command Halt is given when the leading unit has advanced the desired distance. It halts, and its leader commands: Left Dress. Each of the rear units,
when opposite its place in line, resumes tlie original direction at the command of its leader ; each is halted on the line at the connnand of its leader, who then commands : Left Dkess. All dress on the first unit in line.
209. Being in column of squads, to form column of platoons or sections ; or, being in line of platoons or sections, to form the company in line: 1. Platoons (sections) right (left) front into line, 2. March, 3. Company, 4. Halt, 5. Feont.
175 and 188, the necessary commands being substituted.
In forming the company in line the dress is on the left squad of the left platoon ; if forming in column of platoons, platoon leaders verify the alignment before taking their posts.
been verified.
When front into line is executed in double time, the commands for halting and aligning are omitted, and the guide is toward the side of the first unit in line.
At the first command the leader of the leading unit commands: Right turn. The leaders of the other units command: Forward, if at a halt. At the second command the leading unit turns to the right. The command, halt, is given when the leading unit has advanced the desired distance in the new direction. It halts, and its leader commands: Right Dress.
The units in the rear continue to march straight to the front, each when opposite the right of its place in line, executes right turn, at the command of its leader, and is halted on the line at
In the second case, at the command march, the right squad marches forward. The remainder of the company executes 'squads right and then column left and follows the right squad.
At the first command the leader of the leading unit commands, squads right. At the second command the leading unit executes, squads right, and moves off in the new direction. The units in rear march up, and, when opposite their place in the new column, execute squads right.
At the second command the right squad moves forward twice squad distance (20 yards) and halts. The remaining squads execute squads right, and, in succession, when opposite their place in the new line, left turn, placing themselves abreast of the right squad with 3-pace intervals between carts.
squad commands : Foewaed.
At the command^of execution all move off and the squads, in succession from the right, upon gaining their proper interval, march to the front. Only the base squad halts at the fourth command. The remaining squads halt when abreast of the new line.
222. Captains repeat such preparatory commands as are to be immediately executed by their company. In movements executed in route step, or at ease, the captains repeat the commands of execution if necessary.
their companies.
223. When the companies are to be dressed, captains place themselves on that flank toward which the dress is to be made, 6 paces from the nearest gun cart.
and takes his post.
The battalion executes halt, rest, marcMng squads right, to the rear, route .^tep, at ease, obliques and resumes the direct march, as explained for the squad.
When the formation of the battalion admits of the simultaneous execution by companies, platoons, or sections of movements, the major may cause such movements to be executed by prefixing, when necessary, coinpanies, platoons {sections) to the commands prescribed, or platoons right by squads.
to FORil the battalion.
224. For purposes other than ceremonies : The battalion is formed in column of squads. The companies having been formed, the adjutant posts himself so as to be facing the column, when formed, and 6 paces in front of the place to be occupied by the leading squad of the battalion; he draws saber; adjutant's call is sounded or tlie adjutant signals : Assemble.
The companies are formed, at attention, in column of squads in their proper order. Each captain, after halting his company, salutes the adjutant ; the adjutant returns the salute, and when the last captain has saluted, turns about and reports. " Sir. the battalion is formed." He then joins the major.
formed in line or in line of sections.
The companies having been formed, the adjutant posts himself so as to be six paces to the right of the right company when line is formed, and faces in the direction in which the line is to extend. He draws saber and adjutanVs call is sounded.^
halted and dressed to the right.
When the left company is on the line, tlie adjutant, moving by the shortest route, takes post, facing the battalion, midway between the post of the major and the center of the battalion.
their posts.
AVhen all parts of the line have been dressed and officers and others have reached their posts, the adjutant turns about and reports to the major : " Sir, the battalion is formed ; " the major directs the adjutant : " Take Youk Post. Sir," and draws saber. The adjutant takes his post, passing to the right of the major.
tain marches his company off and dismisses it.
227. The commands given in company drill are equally applicable to battalion drill, making the necessary substitution, " battalion " for " company." " company " for " platoon," etc.
228. Machine-gun principles are divided into two classes — fundameiital and .special. The fundamental principles apply generally w'liile the special principles apply to the use of the guns in particular forms of combat, such as attack, defense, advance guards, rear guard, village fighting, and outposts.
must also be considered.
229. The maximum effective use of machine-gun organizations may be expected only when its personnel is thoroughly conversant with the powers and limitations of the gun. well grounded in the principles of its use. thoroughly drilled in the mechanical operation of the gim. and trained by practical exercises to apply principles to concrete cases.
230. Machine-fiun fire is concentrated infantry fire. From this statement are deduced the tactical principles governing its employment. A machine gun has special characteristics. Its fire may be concentrated on a single objective or it may be traversed to cover a wide front.
231. Due to the fixed mount from which the gun is fired, and the mechanical control of elevation and direction, the human element — nerves and excitement, so productive of errors in infantry fire — is to a large extent eliminated.
232. The machine gun aimed and fired by one man delivers an ideally controlled fire. It presents an infinitesimal target and is of such small height that it can generally be moved under cover.
It is comparatively easy to conceal from view and to secure for it effective cover against fire. The machine gun properly mounted and in the hands of properly trained men is for all practical purposes as mobile as infantry in the actual fire fight.
A machine gun, properly handled, is at work in most cases for a few minutes at a time. The machine gun is fired to kill and is not to be used as a mere means of wasting ammunition. The consumption of ammunition will at times be very great, and adequate provision must be made for a plentiful supply.
The machine gun must be amply supplied with ammunition when it goes into position, and proper means must be assured for replenishing this supply. This can only be effected by methodical training of the personnel and by previous arrangements.
233. A machine gun, being a piece of machinery and working at a high rate of speed, subject to a rapid succession of shocks, parts will break, and stoppages will occur. However, the mechanism of a machine gun is not much more complicated than that of the modern magazine rifle. With properly trained men, stoppages and breakages may be corrected within a few seconds.
The tactical rule for working machine guns in pairs arises from the fact that these stoppages occur. This rule is not to be construed that guns .ire to be posted at regular intervals and that adjacent guns should necessarily be posted in such manner to fire on the same objective. It does mean that in the distribution of .guns two guns should be covering any given objective.
234. Machine guns on the march are extremely vulnerable and are for tlie time out of action! However, in well-trained liands, they may be brought into action in a few seconds. Hence the principle that machine guns once located in a suitable fire position should noTlJe moved~ without good and sufficient reason^, and when moved the new position should be selected before thg guns are to be moved, and the movement "macTe flS rapidly "af possible.
235. It is a cardinal principle that the machine gunner does. not hesitate to risk tbp loss pf his gun,,. He must also be prepared to disable it at the last moment in such a manner that if captured it can not be turned upon his own force. If it is a question of leaving the position or staying, the machine gunner
upon the final outcome of the combat.
236. The introUiictiuii of a machine-gun organization into the regiment and the bnttalion organization into the brigade and division, while facilitating the collective employment of machine guns, it does not necessarily follow that the guns should always be so employed. It will often be advisable to detail sections and platoons to work under the orders of battalion commanders. The organization of the company into three platoons facilitates this division, and when the tactical situation is such that it is necessary to make tliis distribution, it should be made without hesitation.
237. The battalion ^ omnianUor under whom the guns are to operate should understand the mission of the guns and the reasons which prompted their assignment to his battalion.
freedom in the execution of the details of his task.
238. The various missions which may be assigned to the machine-gun organization demand the most careful preparation and organization on the part of machine-gun commanders of all grades.
The battalion and company commanders must have a definite gTasp of the situation and fully tmderstand the part they may be called upon to act. Guns temporarily detached should be returned to the control of the company commander the moment the I'easun for detaching them has ceased to exist.
239. During the action machine-gun commanders maintain, by means of agents, the closest possible touch with the next hirrher machine-gtm commander, the commander of the troops under whose orders they are operating, and also with adjoining troops. It is most important that subordinate commanders keep in close touch with the commanders of units to which they may be attached and under whose command they come.
240. Telephones and buzzers can not be relied upon always for purposes of communication. Steps should therefore be taken to maintain communication by visual signaling and by agents or runners. •_;
241. Cooperation is the ke.vuote of macliine-gun tactics, not only between tlie machine guns and tlie troops witn wliich they are worlcing, but also between the guns themselves. The grouping oi' machine guns* into companies and battalions, thus centralizing control, has facilitated the execution of comprehensive schemes of macliine-gun cooperation.
242. The machine-gun commander should take every possible precaution to insure cooperation not only between the guns of his company, but also between his company and the machine guns on either flank.
243. To insure concealment when on the jnflXfe machine gunners disguise their identity as such by adopting the formation of neighboring troops. Other means of escaping detection should be devised and constantly practiced. When machine guns are moving they should w^atch and avoid areas that may be swept by shell fire.
244. To obtain concealment while in position, the fewest possible number of men should he near the guns — two will usually be sufficient. When time, tools, etc., are available, machine-gun emplacements should be dug ; but if it is not possible to construct a satisfactory emplacement, it is considered better to merely seek cover from view, as a hastily-made emplacement merely serves to draw the attention of the enemy.
245. Masks and gloves will facilitate concealment when facing strong sunlight. Special precautions must be taken to prevent the location of machine-gun positions by the artillery. The action of machine guns shelled by artillery is largely dependent upon the tactical situation.
A change of position of 50 yards or so, or the temporary cessation of fire, the guns and detachments getting under cover, may mislead the enemy and enable the guns, later, to obtain a good target readily.
The progress of the firing line must therefore be watched cnrefully with a view to pusliing on a certain number of macliine guns to closely support it whenever possible.
4. Fire from a forward position.
249. Every opportunity for the use of overhead fire should be seized. All suitable ground, buildings, etc., should be utilized for this purpose when possible.
jected to it. which assists the subsequent advance.
251. Often it may be possible to push machine guns forward where the ground is favorable, so that they can assist the advance of troops on their right and left.
Opportunities of this kind should not be neglected. It is possible for machine guns thus employed to remain undetectefl, although well in front, provided the preliminary reconnaissance is properly conducted.
252. Enemy machine guns, are the weapons most likely to stop an attac-lc! Every effort should be made to locate them with field glasses or telescopes, with a view to concentrating the fire of machine guns on them, and also to indicate their position to rhe artillery.
253. The machine-gun conunander must be fully informed of the plan of operation at the earliest possible moment. He should make a careful reconnaissance of the ground prior to the attack. The machine-gun commander is informed of the intended action of the automatic rifles. Having made the reconnaissance and received his orders, the machine-gun commander assigns definite tasks to his companies, platoons, or sections. The guns may be divided into groups, some to go forward with the infantry, some to cover their advance, and others to act as a reserve.
. 254. In this manner each machine gun, or group of machine guns, is given a definite tasli. Before action commences every gun squad sliould thorouglily understand what is expected of it. It must be clearly understood by all officers that the machine guns have definite tasks, that they are under the orders of the machine-gun commander,
255. The machine guns in the attack are separated into three classes: (1) Guns going forward with the attacking infantry, (2) guns that are to cover the infantry advance, and (3) guns in reserve.
1. The guns to go forward with the attacking infantry,
(a) The number of machine guns to go forward depends upon the tactical situation, the front to be attacked, the nature of the ground, the number of guns available, etc. (&) The time of their advance is determined by the terrain and the success of the firing line. They should very rarely advance with the leading line of riflemen. This is the duty of the automatic rifles, the fire of which should suffice to hold the position won until it can finally be consolidated _by the machme^guns. ' "^
~TTTel3rogress of the firing line must be carefully watched, so that the guns may be brought forward at the earliest possible moment.
enemy position being attacked.
Some will be pushed out in front of the line to keep down enemy fire while the infantry are getting out of their trenches and througli their obstacles. These may be in saps, crops, folds in the ground, etc.
When the attacking firing line masks the fire of the machine guns, the machine guns should, if possible, direct their fire past the flanks of the attacking troops so as to keep down flanking fire and prevent flank attacks.
If attacking troops are forced to lie down between the enemy's position and the guns, the machine guns must keep down the fire of the enemy's rifles and machine guns.
Wlien tlieir role of covering fire is completed, they should automatically come again under the control of the machine-gun commander.
Orders to the machine guns detailed for this task may, if necessary, include general instructions to govern their action after the task has been completed, pending receipt of further orders from the machine-gun commander. It must, however, be remembered that it is usually dangerous to prescribe to a subordinate at a distance anything that he should be better able to decide on the spot with a fuller knowledge of local conditions, for any attempt to do so may cramp his initiative in dealing with unforeseen developments. 3. Tlie guns as reserve.
Guns kept as a reserve will be under the control of the machine-gun battalion or company commander, acting under the instructions of the regimental, brigade, or division commander. Owing to their characteristics, machine guns are valuable as a reserve of fire power, and when kept in reserve in the hands of the commanding officer may prove of the utmost value at the critical moment. It must be remembered, however, that a great development of fire power is most useful in thp oppiiin^ gtnges of m^ nttnHc, to povpr th^ advnnce of tbft jjifantry, nnd it is a mistake to keep guns in reserve if they can be usefully employed in supporting the advance. These guns may be used for long-range searching fire on ground behind the enemy's line, which is likely to hold supports or reserves, but must be available to move forward at once when required.
256. The great fire power of machine guns relative to the space they occupy, the rapidity with which they may be brought into or out of action, and the ease with which they can change the direction of their fire render them especially suitable for the protection of threatened Jianks and for filling gaps w^hich may appear laterally or in'depthr*^ny of the guns mentioned in the Ijrevious paragraphs may at times be employed in this manner.
257. During an attack it may be advisable to continue to hold certain tactical points which have been captured until the attacking troops have made good their next objective. The characteristics of machine guns fit them for this duty ; their use will
fantry.
258. Arrangements for ammunition supply, belt filling, ammunition depots, etc.. mast be made before the action connnences. An officer may be placed in charge of these arrangements.
with the commanding officer.
260. As far as possible, the guns of a company should be kept together. If this can not be arranged, in no case should_ an isoInted junc1-i1rip£TniJjp ]>rony]it into nr-tio]]. for a siHgle^un may I)e"TemporarrTy disabled by a jam or a breakdown of its mechanism at the decisive moment.
261. An officer commanding a group of machine gims should avoid becoming involved in a duel with the enemy's machine guns, but should use his fire against important targets — the enemy's batteries, reserves, and supports.
262. In occupying a defensive position a special reconnaissance should be made. Not only the position itself, but the ground in front, in rear, and on the flanks must be thoroughly reconnoitere<l. The distribution of all the guns, regimental, brigade, and division, is made under the direction of one officer, the senior machine-gun officer of the command, In this manner, and in this manner only, is it possible to employ a number of guns properly coordinated in a comprehensive scheme.
In the occupati(m of a defensive position the duties of the automatic rifles must be carefully considered and coordination established between the two weapons to insure mutual support.
4. A proportion of the guns are kept in reserve. When the ground is suitahle, these may be used for indirect or overhead fire if the results are likely to justify the expenditure of ammunition, and the readiness of the guns to take up other tasks is not impaired. It will often be found advisable to prepare macliine-gun emplacements at important tactical points in rear of the front line, and to detail guns for their occupation if necessary. Preparation in this respect will facilitate a rapid readjustment of the fire upon any point.
.">. ^>econdary^ positions and lines of re^iTf^i^ipTit are reconI'loiterelHi "and "steos are taken to insure that the (lerachmenrs are familiar with them. In case of a withdrawal becoming necessary, machine guns in supporting positions cover the retirement of the infantry and guns in the front line.
(3. Cooperation is aiTanged with the automatic rifles of the companies, which can c"ov?r tne less important approaches or small depressions or hollows which the machine guns can not sweep.
264. Each machine-gun team should k-^.ow the line of retirement, and the positions of the guns on its riglit and le^l. A range card is made for each, gun position.
and as uTuch cover as time permits provided for the men.
266. Firing at the longer ranges reduces the effect and betrays one's strength and position prematurely to the enemy. In the defense it is advisable to let the enemy approach to vrithiu short range, and then open fire, especially when the dei'ender is in a strong position.
267. It will often be a gain to keep the guns silent at the beginning of the hostile advance, while only the point of the enemy's advance guard or a thin liiie of skirmishers is in sight, and to wait until fire can be opened upon the main advance. Ranges are measured beforehand, and, if possible, marked. In all cases, the sudden and unexpected opening of heavy fire will produce more effect than the expediture of the same amount of ammunition when the tire gi-adualiy develops and does not come as a surjin^ to the attacking force.
26 §^ IirnlT cases the machine guns should, if possible, be protected from fire from the front. At the same time they should be able to flank the front of tlie position with fire. Thus, although each machine gim may be fired to the flank, its front is swept by the fire of another machine gun.
machine gun from the tripod and fire from the top of the parapet, (b) Lift the machine (r\m and tripod out of the trench and fire it from some previously selected sjjot.
269. Arrangements for firing at night should be made. The day and night gun positions will probably be different ; the changes from the one to the other should be made just after dark and just before dawn.
270. Comnmni cation between the machine-gim units must be arranged v>ith care. JMachine-giui officers must keep in touch with neighboring guns and with the firing line.
to recognize, such as crcssrouds or single objects, or places v/hicli can easily be located on the map. It is important that gnns sIiouUl merge into the surroundings, and straight edges or distinct shadows should not be m.ade.
272. Banks of rivers, canals, and railway ditches, fold ; in the ground, hedges, palings, or walls, also mounds of earth, may be used either to afford a covered line of approach and supply to a gun position or else a gun position itself. V\lien firing over the top of the cover greater protection is given if hollows are scooped out for the front legs of the tripod.
doors in line or past the sides of the house. When firing from a window, door, or hole in the roof, the gun should be placed well back for concealment. When firing from a cellar care should be taken not to cause a cloud of dust to rise and give away the ]iositioii. A means of retirement and nlt^i'native emplaceiuents should lie arranged. Overhead fire and observation mayoften be obtained from high buildings.
274. Woods and crops provide cover from view, facilities for communication, and good lines of approach or supply. In neither should guns be placed too near to the front edge. In woods it will often be possible to construct hasty overhead cover.
275. If a barricade has been constructed across a road, machine guns should not be put on the barricade itself, but, if possible, in a concealed position to a flank from which they can sweep the road.
276. Haystacks do not as a rule afford a very satisfactory position, but guns may be placed in a hollow in front or behind, firing past the side, or else in a hollow on top, firing through the front face of the stack. A machine gun concealed in a field which is covered with cornstalks, manure heaps, or mounds of roots is difficult to locate.
277. Wood stacks, planks, logs of trees, and farm inmlen-.entt; may be used to conceal guns ; cover from fire can often be obtained by the additioiT'of bricks or sand bags.
279. Marching constitutes the principal occupation of troops in campaign and is one of the heaviest causes of loss. This loss may be materially reduced by proper training and by the proper conduct of the march.
280. The training of machine-gun organizations should consist of systematic physical exercises to develop the general pl:ysique and of actual marching to accustom men to the fatigue and hardship incident thereto.
Before mobilization troops should be kept in good physical condition and so practiced as to teach them thoroughly the principles of marching. At the tirst opportunity after mobilization the men should be hardened to cover long distances without loss.
281. With new or untrained troops, the process of hardening the men to this work must be gradual. Immediately after being mustered into the service the physical exercises and marching should be begun. Ten-minute periods of vigorous setting-Tjp exercises should be given three times a day to loosen and develop the muscles. One march should be made each day with full equipment, beginning with a distance of 2 or 3 miles and increasing the distance daily as the troops become hardened, until a full day's march under full equipment may be made without exhaustion.
282. A long march should not be made with untrained troops. If a long distance must be covered in a fevr days, the first march should be short, the length being increased each succeeding day.
283. Special attention should be paid to the fitting of the shoes and the care of the feet. Shoes should not be too wide or too short. Sores and blisters on the feet should be promptly dressed during halts. At the end of the march feet should be bathed and dressed ; the socks and, if practicable, the shoes should be changed.
march and after arrival in camp. On the march the "use of water should, in general, be confined to garglin.cr the mouth and throx'it or to an occasional small drink at the most.
285. Except for urgent reasons, marches should not begin before an hour after daylight, but if the distance to be covered necessitates either breaking camp before daylight or making camp after dark, it is better to do the former.
286. A halt of 15 minutes should be made after the first half or three-quarters of an liour marching; thereafter a halt of 10 minutes is made in each hour. The number and length of halts
' may be varied, according to the weather, the condition of the roads, and tiie equipment carried by the men. When the day's '. march is long a halt of an hour should be made at nooa and the , men allovred to eat.
287. The rate of march is regulated by the commander of the leading company of each regiment, or, if the battalions 'bo separated by greater than normal distances, by the commander of the leading company of each battalion. He should maintain
I leads.
288. The marclung efficiency of an organization is judged by ^ the amount of straggling and elongation and the condition of I the men at the end of the march.
2f to 3 miles per hour.
290. The marching capacity of trained infantry in small commands is from 20 to 25 miles per day. This distance will decrease as the size of the command increases. For a complete division the distance can seldom exceed 12^ miles per day unless the division camps in colunm.
pline.
The march order should contain such instructions as will enable the troops to take their proper places in column promptly. Delay or confusion in doing so should be investigated. On the other hand, organization commaudei-s should be required to time their movements so that the troops will not be formed sooner than necessary.
^ The nttrseshoer, the saddler, the company clerk, the cooks, and two privates march with the field train, under command of tlie officer in charge of the train.
292. The machine-gun commander habitually accompanies the commanding officer of the unit to which he is attached. A machine-gun reconnaissance party marches with the advance element of the command
PROTECTION OF THE MARCH.
293. A column on the march in the vicinity of the enemy is covered by detachments called advance guards, rear guards, or flank guards. The object of these covering detachments is to facilitate the advance of the main body and to protect it from surprise or observation.
They facilitate the advance of the main body by promptly driving off small bodies of the enemy who seek to harass or delay it ; by removing obstacles from the line of advance, by repairing roads, bridges, etc., thus enabling the main body to advance uninterruptedly in convenient marching formations.
They protect the main body by preventing tbe enemy from firini? into it when in close formation ; by holding the enemy and enabling the main body to deploy before coming under efl'ective fire ; by preventing its size and condition from being observed by the enemy and in retreat by gaining time for it to make its escape or to reorganize its forces.
enemy on a wide front.
297. With advance guards the machine gun will supply a useful stiffening which will often make it possible to use a smaller number of men, or, again, by increasing the number of machine guns the advance guard may be given a striking force that will enable it to take a more strongly aggressive tone toward the enemy.
298. As the preliminary action of the advance guard draws to a close and the main body deploys into line and begins the more serious engagement, it will generally be well to withdraw the machine guns from the position which they have occupied to meet the first emergency, in order to assign them to the work they are to do in the actual battle.
299. The characteristics of machine guns render them, as a rule, more suitable for employment with the reserve than with the support, but the size of the support may necessitate machine guns being attached to it.
an advance for long periods.
302. In occupying a rear-guard position with machine guns the ordinary principles of the defense apply, but the following points should be specially noted :
6. A proportion of the machine guns should occupy the positions in rear, before all the machine guns retire from the forward position. Thus the retirement of the last gun can be covered.
303. Rear-guard fighting is particularly well adapted to their power of suddenly opening a heavy fire, and the business of the machine-gun commander will be to choose, if possible, a position from which this fire will come as a sui-prise to the pursuing troops. Having accomplished his object of checking the enemy's movement and forcing him to deploy for the attack, he will fall back to another position where he can repeat the same maneuver.
304. The ease with which a machine gun can be concealed, its mobility, its adaptability to night firing, and its concentration of fire on a narrow frontage makes it the ideal resisting weapon for use wth an outpost for the purpose of covering roads, bridges, defiles, or other marked lines of approach.
of riflemen. However, the maeliine gun is solely for the purpose of increasing the stopping power of the outpost, and in return it must have the protection of the outpost.
303. Aside from the use of machine guns in covering defiles, advantage may be taken of their characteristics of concentratedflre power to place them in salients and reentrants and at other points where the establishment of a heavy firing line is not feasible.
307. The size and disposition of the outpost with the number of guns assigned to the different subdivisions thereof depends upon many circumstances, such as the size of the whole camp, the proximity of the enemy, and the situation with respect to him. the nature of the terrain, etc.
308. The guns attached to the outpost, if sufficient in number, may be placed at or near the line of resistance, with a section covering each of the main avenues of approach, or if too few in number to admit of such a distribution, emplacements should be prepared or firing positions reconuoitered and located covering the line of approach, the guns being held in reserve at a central point in rear from which tliey may be moved easily and quickly to that portion of the line v.iiere they are needed.
309. Unless an attack is imminent, machine guns assigned to the outi30st do not occupy their fire position during the day, but are held as reserves in their sector. However, emplacements or firing positions are prepared, routes marked, range cards made, and all preparations for immediate action completed.
310. The night position for each gun is very carefully selected and arrangements made for night firing, and the gun placed in position before dark. The guns are so located that an enemy in advancing must pass over or occupy ground swept by their fire.
311. The avenues of approach to be covered must be considered in the order of their importance and an endeavor made to leave unprotected no approach by which an enemy might advance.
4. The disposition to be made of his carts.
313. The machine-gun commander upon arriving at the designated subdivision of the outpost to which he is assigned is given the location of the infantry sentinel or sentinels. He then —
with the unit to which he is attached.
314. Sentinels over machine guns as part of an outpost are, at night, 'posted in pairs, two men to each gun in position. Usually one sentinel will be sufficient during the day.
action of patrols, etc.
(?) What the signal is for- opening fire, and whether or not he is to open fire on his own iniiiative. I In case of an attack at night, No. 2 sentinel catls the other I men of the gun squad.
Relieving gun detachments and sentinels will assure them! selves that they are fully conversant with the instructions for i the gun squad and the sentinel as described in this and the pre: ceding paragraph. In addition, relieving sentinels should be , Informed whether or not the gun has been fired during the pre' vious relief; and if so, at what target and from what gun [ position.
315. As soon as the ritlemeu have made good one edcje of a viUage, machine guns are brought up in close support. They then searcli windows, doorways, roofs, etc., liliely to be held by the enemy.
320. Ammunition supply is of vital imp(»rtance in any engagement and must be given very careful consideration and forethought. It is a subject that is very much neglected in our Army. The duties of the various commanders with respect to ihe supply of ammunition are outlined in the chapter on the " r>uties of the personnel, before and during combat."
with the gun at all times.
The belt-filling station must be established as near the gun position as the terrain and the enemy's fire will perrair. At this station will l)e the 3,500 rounds, 2 water boxes, and the beltfilling machine.
322. It is the duty of the fire controller (section leader, platoon leader, or company com.mander) to mark the place for the belt-filling station and establish it with Nos. 5 and 6 as loaders.
After establishing this station the fire controller next causes the ammunition on the ammunition cart to be unloaded, providing he expects to remain in his position, and immediately sends the ammunition cart to the combat train to refill.
323. During the time the position is being occupied it is the duty of the commander of the combat trains to communicate with the fire controller and inform him of the best meeting place for the ammunition carts and the combat train. As soon as the ammunition carts are refilled from rhe combat train the combat train must refill from the ammunition train. The succeeding paragraph may apply at times during the offense.
bat trains to unload their ammunition at some place convenient
I and accessible to the ammunition carts. The ammunition carts I can then refill, carry anmnmition forward as far as permissible, I and also unload. From that point forward the ammunition i must be carried by hand to the belt-filling station, and from ' the belt-filling station to the gun positions. If ammunition j must be carried over fi.re-swept ground froui the amnuuiition , carts to the belt-filling station, the cases may be dragged or ; opened and the bandoleers carried by the men. If the men are I required to crawl forwarJi, then five bandoleers is a good load I per man.
326. General reconnaissance is the function of the infantry and cavalry. Machine-gun commanders should be kept sufliciently well informed of the situation to enable them to use their guns effectively.
The machine-gun commander makes such special reconnaissance as is necessary to insure the proper posting and the effective employment of the gitns in the execution of the assigned tasks. For this purpose the machine-gun commander is assisted by reconnaissance officers and scouts.
2. AVhen necessary that guns be brought into action quickly, promptness in opening fire is the main consideration. No time should be wasted in selecting positions, for in such a case concealment will be out of the question. The machine-gun commander with an eye for groun.d may, however, make use of the cover afforded in his immediate front and thereby gain some little advantage.
8. All machine-gun commanders invariably precede their commands to the position to be occupied. Every effort should be made to conclude all preliminary arrangements for action prior to the arrival of the guns. Delay in opening fire must not be caused by lack of timely reconnaissance and preparation.
4. The machine-gun connnander should accompany the commander of the troops on the preliminary reconnaissance, should be kept constantly informed as to the tactical situation and the plan of action, and should receive early instructions as to the special tasks to be performed by the machine guns.
5. At the earliest opportunity the machine-gun officer reconnoiters and selects the positions for the companies, or sections, in accordance with the instructions he has received and the tactical requirements of the situation. He informs his subordinate commanders when and where they are to report to receive instructions and undertake their own reconnaissance. It Is important that the subordinate commanders be given concise and detailed instructions.
(/) The time for quitting transportation should 1)0 specified at this time. if. determined, otherwise this information should be sent back later on.
7. As soon as positions are selected and routes determined, agents or scouts may be sent to meet the machine-gun organizations and guide them by the best routes to their positions.
S. Reconnaissance oflicers accompany advanced troops in order that they may secure early information as to the enemy and give the machine-gun commander detailed information as lo the ground, favorable positions, and routes. A reconnaissance officer operating in this manner, as well as one arriving with his commander, examines the neighborhood of the position, locates his own troops and those of the enemy ; prepares firing
commanding ofticer and relieves the latter of details.
9. Company reconnaissance oflicers are habitually under the orders of the machine-gun commander on marches in the presence of the enemy. Scouts may be employed to assist reconnaissance officers and supplement the information secured by them.
RECONXAISSAXCE OFFICEES.
327. A reconnaissance officer attached to advanced troops sliould, as soon as possible a^ter the determination of the enemy's location, submit to the machine-gun commander a report, giving all obtainable information as to the enemy and describing the most suitable positions for the machine guns. This report should be accompanied by a sketch, showing the enemy's position, the selected gun positions, the characteristics of the country intervening between the two, and such other important information as may be readily set forth. The report should embrace information as to —
328. 1. L'ntil all elements of the command are in position, agents are especially careful, even without instruction, to watch for and render information to the captains, officers, men of the various details, and others entitled to it.
information to others.
(&) Seek the best routes of approach and study ihe ground in and around the pojiition. to enable hira to guide elements into new positions and to transmit information bet^^'een the major and neighboring troops.
4. Agents must keep in mind the following :
(a) Before starting with a message they ask the following questions, if their information is not clear : (*L) What is the official designation of the one to whom the message is to be delivered?
(h) Important messages in writing should have their purport understood by the bearer, so that, if necessary, they may be destroyed to prevent their felling into the hands of the enemy.
thereon.
(7j) If avrare of the na^i;ure of the message carried, after delivering it, report any circumstances affecting the situation which have arisen since leaving the sender. (l) Always repeat a verbal message, word for word, in the presence of the sender, making certain they understand the meaning of the message. (711) After diligent search, if the person to whom the message is sent can not be found, endeavor to lind some other person who can take advantage of the information conveyed. Whether this can be done or not. always report back to the sender with full statement of facts in the case. (n) Unless otherwise directed, always report back to the sender whether or not the message was delivered, (o) When a messenger carries a message unsealed or not marked " Confidential " he will permit commanders along the route to read it.
and date wiien they read the contents.
Wlien it is desirable that neighboring troops get information from a message sent to a superior that fact is noted on the envelope, and it is the duty of the messenger to see that they get it. He must see that they initial the envelope and record the hour and date thereon.
2. After hiiving received his orders the major makes a special reconnaissance, assisted by reconnaissance officers and scouts, in order to obtain information concerning —
opened,
(/) Orders for flanli protection and reconnaissance, unles covered by orders froni higher authoritj". 7, Orders comnumicatlon witli —
them to it.
3. Superintends the work of the signal corporal and signal private in establishing communication with the various gun positions. It is a general rule that the buzzer wire should be laid from reay- to front. The hand reel will then be in front, and if a forward movement is made the length of the wire can easily be extended.
THE SIGNAL CORPORAL.
336. 1. Under general supervision of the battalion sergeant major, has charge of, and is responsible for. all signal equipment of the battalion, makes such tests and repairs as he ma.v be authorized to make, and at the first opportunity reports to the adjutant all trouble which he can not remedy.
2. Commands the battalion signalmen on the march. .3. Learns from the leading company commander when communication is to be estal)lished and at once reports to the major.
established or broken.
G. Learns from the adjutant or major what artificial cover is required for the station, and, assisted by signalmen and agents, constructs it at the first opportunity.
When the company is part of the machine-gun battalion, the position of the captain is with his company, and is such that— («) He can best control his company. {b) He can keep in easy communication with battalion headquarters.
tion carts, communication between the belt-filling stations and the combat train. (PI. YII.) (c) Giving instruction to the train lieutenant to keep ammunition carts replenished with ammunition.
and supports.
Note. — Arrangements must be made previous to the attack and each gun given explicit instructions as to its duty. The captain will rarely be able to command his guns in this situation, but will rely upon the platoons, sections, and gun squads carrying out the preconceived plan of action.
{a) Securing by personal reconnaissance and the assistance of scouts such information of the enemy, our own troops, or the terrain as is desirable or ordered.
required for the direction and conduct of fire.
(cZ) Observing the field of action, watching for movements of the enemy and our troops fiat may affect the situation, and keeping his commanding officer informed as to changes in the situation. Note. — For detailed duties of reconnaissance officers and scouts, see paragraphs 327-329.
345. Under the captain's direction — (a) Is responsible for all signal property. (&) Makes such repairs as he may be authorized to make.
(a) Give commands ordered by the captain. (&) One acts as horse holder for the captain, (c) Act as messengers when directed.
observer and platoon and captain. (PI. VIII.) (c) Specifies the kind and rate of fire. (/) Gives commands for opening fire.
(/) AVhen his squad is ready, signals Ready. At the platoon or section leader's order, or signal, to commence firing he gives the proper command for his gunners to open fire.
(g) If a time has b^eu set for opening fire, he opens fire at the specified time without command. 7. Carefully instructs his squad covering —
355. 1. Carries the gun.
2. Personally cleans and looks after the gun, insures that the I mechanism is working smoothly and that water jacket is full. I 3. Observes his own fire when possible.
383. Under the direction of the train lieutenant he commauds th(^ kitchen wagon while in the held and is responsible for the preparation and delivery of meals to the men while on the march and during engagements.
367. It is essential that a iiuichino-gim ofRccr have a thorou?:li and practical knowledge of ho^Y to care for, condition, and tralQ the animals under his charcre. Deficiency in this knowledge will result in material and avoidable wastage of animals in time of war. The animal requires intelligent care in order that his health and strength may be preserved ; he must be in hard and physically tit condition, else the amount of useful work he is able to'perform will be greatly reduced and his power of resistance to injury and disease lowered ; and he requires careful training in ordei* that he may work intelligently and obediently and with the minimum expenditure of muscular and nervous energy. Oflicers should make themselves thoroughly acquainted with the physiology- of the animals under their charge and with the effects of different m.ethods of treatment, changes of diet, etc.. upon the systems and power of endurance of these animals. In addition, they should have a familiar knowledge of the symptoms and treatment of the diseases that are common to horses and mules, what to do in emergencies, and a good knowledge of the effects of medicines issued. They should also possess a practical understanding of the principles of horseshoeing. The ofhcer in charge of horses and mules must carefully instruct his men in the treatment, stabling, watering, feedinL-. grooming, and exercising of the horses, and by continuous supervision and in.«?truction insure himself that his instructions are thoroughly understood and fully caiTied out. 13G
sudden or abrupt movement.
An animal must never be struck or threatened about the head. Such treatment quickly makes him head shy and renders his proper control difficult and exasperating.
Never kick, strike, or otherwise abuse an animal. On rare occasions punishment may be necessary, but it must be administered immediately after the offense has been committed, and tlien only in a proper manner with whip or spur and never in the heat of anger.
Before taking an animal out, carefully examine him and make sure that he is tit for work. In particular — Has he eaten his food, especially his grain? Is his breathing normal?
After taking the animal out, always vralk him the first mile to start the circulation in his legs. Habitual disregard of this rule leads to foot and leg trouble that will render him unserviceable before his time.
TO COOL A HEATED ANIMAL.
369. To be certain of no ill effects, an animal brought to the stable in a heated coudifioii must be cooled out and dried before he is left tied up in his stall. To cool the animal, walk him about slowly under a blanket if the air is chilly. Occasionally interrupt the walking by giving him a good brisk rub down and two or three swallows of water. Walking is especially valuable, because this gentle exercise keeps the nuLscles uKning slowly and so assists in working any excess of blood out of them and out of his vital organs. The brisk rub'oing dries him and assists in bringing the blood back to the skin, and so aids in restoring the circulation to the normal. If tlie surface of the body becomes chilled, or if the cooling out is too sudden, the congestion existing in the lungs or in the feet may not be relieved, and pneumonia, lamiuitis. or other troubles will then result. A sudden stoppage of hard work is always bad for the feet and is very liable to result in laminitis. The water given in small quantities slowly cools the horse internally and so aids in sending the blood back to the surface and restoring the normal circulation and temperature. The cooling-oiit process must aUcatjs he a [irudual one. To throw water on any part of a heated horse is particularly dangerous.
hock, and inside of his hind quarters sponged with cool water.
When he comes in wet with rain lie should be scraped, then blanketed, and his head. neck, loins, and legs rubbed. If the weather is cold, an extra blanket should be put on for 20 minutes. The wet blanket should bo changed when he dries.
Never wash the legs. This practice is one of the surest means of causing scratches. The legs should be rubbed dry and bandaged loosely with thick bandages. Scraps of gunny sacks are satisfactory for this purpose. It is far more important to have the legy warm and dry than clean. The best method of treating nuuldy legs in order to avoid scratches is to bandage them ; this liceps ihem warm until they are dry. and then lirush them clean.
370. The stable personnel includes the stable sergeant, the liorseshoer, the farrier, the saddler, the drivers of field and combat vehicles, and the stable detail.
371. The lieutenant in command of the train is responsible to the captain for all duties in connection with the care of the horses and mules, the stables and stable mana.wment. He is assisted by the stable sergeant, v\iio has Immediate charge of the stable personnel, of tlie jx^lico and sanitar.v condition of the stable, corral and picket line, and is the custodian of the forage and the stable property. He will keep records of forage, of the property in his charge, and of the animals.
member of the stable personnel will assume his duties.
Sufficient men are detailed as stable police to perform the general police and to remove all manure as it is dropped, either in stables, on the prcket line, or in the paddocks, during the day. The stable police also assist in the feeding, watering, and bedding of the horses.
number for duty.
A record will be kept of the departure and return of all animals, except those participating in habitual formations or duties, and the stable sergeant will satisfy himself that persons taking out animals have proper authority to do so.
der the direction of the stable sergeant.
The beddin.g is taken up, carefully shaken out, and assorted. All parts of the bedding which can be used again are taken to the bedding racks and spread thereon for a thorough drying; parts which can not be used again are sent to the manure heap.
Special attention is necessary in this matter, as the allowance of straw. 100 pounds per month per animal, is Insufficient under most favorable conditions. In the evening the dried bedding, mixed with such fresh bedding as may be necessary, is laid down. The bed must be soft and even with the thickest part toward the manger.
Manure and other refuse must not be allowed to accumulate in or near the stable. It will be disposed of daily in the manner prescribed by the commanding officer.
each stable.
Animals will be assigned permanent stalls, by section, in the usual order of their formation. They will be placed on the picket line in the same order. Over each stall will be placed the name and number of the animal and the name of the man to whom assigned.
Tlie presence of unauthorized persons about the stables at any time is prohibited. This applies to men of the organization who have no duties to perform as well as to strangers. The stable sergeant is charged with enforcing this rule.
373. In a stable with a loft, ventilation from the top is always insufficient, and the openings in the sides, above the liorses, should be kept open except when it is necessary to close those on the windward side to keep out rain or snow.
precaution taken to have good ventilation.
374. Foul air and dami)ness are the causes of many diseases of the horse; hence the importance and economy of spacious, clean, dry, and well-ventilated stables.
It is impossible to give the horse too much fresh air, even in the coldest weather. The stables should be considered as merely a shelter from storms. The more nearly the air of the stables approaches the purity and temperature of the outside air the
of the animals.
xV practical and satisfactory test that a stable is properly cleanwl and ventilated is that on entering it the sense of smell detects no apparent change from the air outside.
to prevent the escape of animals.
375. Stall floors should be kept in thorough repair at all times. If of wood, broken planks must be immediately replaced and spikes kept driven well into the wood. If of dirt, only clay should be used. Gravel, ashes, or sandy earth is not suitable.
The sloping of the stall floor from the manger is injurious and uncomfortable for the animal, causing him to stand in an unnatural position, with the forelegs higher than the hind ones. It is natural for a horse to paw a hollow for his front feet, so that he can stand with his hind quarters elevated.
contents assigned to places and kept in order.
If practicable, all woodwork within reach of the horses should be protected with sheet metal or painted with a thin coat of gas tar ; other woodwork and brick should be painted a light shade and then kept clean and free from dust.
mash or other soft food.
During the day, except in very cold or stormy weather, the animals, when not being used or fed, should stand at the picket line or in the paddocks. In hot climates, however, if there is not sufficient shade on the picket line or in the paddocks, it is better to keep them in the stables during the heat of the day.
377. In permanent or semipermanent camps cantonment stables are built when practicable. They are usually sheds without sides, wide enough for a double row of stalls. The double stalls should not be less than 9 feet wide by 10 feet deep.
Ample ditches should be dug back of the stalls. All rules for the management of the permanent stable that are applicable apply equally for the cantonment stable.
378. Permanent picket lines of l^-inch manila rope or of f-inch steel wire cable are erected near every stable, to which animals are tied for fresh air, for grooming, and to permit the stable to be cleaned.
The picket-line supports should be posts not less than 6 by S inches by 9 feet long, spaced 50 feet apart, the end posts securely guyed. The line is run through the posts. One end of the line should be provided witii a means of taking up slack in the line.
379. Shallow trenches should run along each side of the line beliind the animals to carry off the rain and the ground upon which the animals stand filled and graded with a slight slope from the Hue.
kept smooth, In the manner indicated for stall floors.
381. Troops in camp may have no stable, in which case aninuils are cared for entirely on the picket line and in the corral. If space of ground permits, a corral may be built adjoining the picket lines. The corral fence is built from such materials as can be secured.
382. It is a good plan to build a corral fence around and inclosing the picket lines of new organizations. This is also true of organizations having a nevr lot of animals or camped close to other mounted commands, thus avoiding the often serious annoyance of lost animals. Such a corral also assists in the pi went ion of the spread of contagious diseases among the animals.
383. Field picket lines should be carried by all organizations ]i:',ving animal transportation while in the field, and are used wlienev J the troops go into temporary camps.
This field picket line may be stretched between the wagons or ustH.l as a ground line. If used as a ground line, it should consist of 1-inch manila rope 45 feet long, into iron rings at each end, 20 feet of ^-inch rope for a reeve rope, two end pins, and a center pin.
384. The auimals are tied on the line so tliose in eacli section stand togetlier. Precautions sliould be talcen to tie animals of mean disposition where they can not injure their neighbors by ticking or biting. In cold, wet, or windy weather animals like to stand with their tails to the wind, and effort should be made to place the lines so that this will be possible. In hot weather endeavor should be made to get as much shade as possible; if the camp be permanent, shade for the lines nuist be extemporized. Continued standing in the hot sun will seriously debilitate the animals.
385. The sanitation of the picket lines in a permanent or semipermanent camp demands constant attention. Ditches should be cut to allow them to drain easily, and manure and foul litter must be removed daily. During the fly season the lines should be sprinkled once a week with crude oil or other inflammable material and burned off.
up, the position of the lines should be changed.
If there be an extreme range of daily temperature, horse covers are of value. The use of covers, however, is liable to abuse. A horse can stand great cold when properly acclimated. A cover saves feed, but its use makes the animal dependent upon it and renders him much more liable to colds and chills than if his coat had been entirely relied upon to afford him proper protection. Cold rains will tell on the condition of uncovered horses unless they get extra food.
386. Drill or work requiring the use of the animals of the command is followed immediately by stables: the horses and mules are then thoroughly groomed and the harness and equipment cared for and put away in good order. The lieutenant in charge of the train is pi'osent and in immediate supervision of this work. He is assisted by the stable sergeant.
On Sinidays or holidays the animals are thoroughly groomed once during the day. This is usually done at morning stables. The lieutenant in charge of the train or some other officer of the company is present at this time.
On A\-ork days mornincr stables Jire held for the animals before they go out. At that time each section leader superintends the removal of manure and foul litter from his stalls or picket lino, seeing' that it is placed in piles convenient for carting away : he causes the men of his section, after cleanin;r their stalls, to look over and carefully examine the animals t© see that they ai-e fit for work (oG8). and he causes each to be l)rushed clean of dirt or manure. The lieutenant in charge inspects the general condition of the animals and stables at this time.
On returning: from a drill or exercise and after a march the animals are unbridled, their collars and traces removed, and the irirths loosened. The men then put on stable clothes, relieve themselves, and prepare for the work of caring for the equipment and grooming. After the bits and collars are cleaned, the remainder of the harness is removed from the horses and disposed of deliberately, the necessary cleaninu' being done at the same time and in the most convenient manner. After the allotted lime has been given for the care and disposal of the harness and equipment, the animals are groomed and cared for.
Th.e horses of officers are groomed by specially detailed men.
The men are marched to the picker line, take the position of stand to heel at the direction of the senior sergeant present, and then begin work as soon as the senior sergeant commands: Co m r. I enve f/ro om i na.
387. Grooming is essential to the general health and condition of the domesticated animal. Horses and mules improperly groomed, with ragged manes, unkempt pasterns, feet improperly looked after, forms an indication of an inefficient organization. Clean animals, properly harnessed and smartly turned out. add to the esprit of an organization and give a fair indication of its discipline and efficiency.
face answers equally well.
The currycomb should never be used on the legs from the knees and hocks downward nor about the head, and when occasionally required to loosen dried mud or matted hair on the fleshy parts of the body it must be applied gently.
To groom the horse proceed as follows :
First clean the front legs, then the hind legs. They will thus have time to dry while the rest of the grooming is being done. Next, on the near side, with the currycomb in the right hand, fingers over back of comb, and the brush in the left hand, begin brushing at the upper part of the neck, the mane being thrown to the other side out of the way ; thence proceed to the chest, shoulders, back, belly, flanks, loins, and rump. In using the brush the man should stand well away from the horse, keep his arm stiff, and throw the weight of the body against the brush. The principal work of the brush should follow the direction of the hair, but in places difficult to clean it may be necessary to brush against it, finishing by leaving th(^ hair smooth. After every few strokes clean the brush from dust with the currycomb.
Finally go
over the legs once more and clean out the hoofs. In cleaning the mane and the tail begin brushing at the end of the hair and gradually work up to the roots, separating the locks with the fingers so as to get out all scurf and dirt. Tails require frequent washing with warm water and soap. The skin under the flank and between the hind quarters must be soft, clean, and free from dust. Currycombs, cords, or common combs nmst never be applied to the mane or tail ; the brush, fingers, and cloth are freely used on both.
into a rope. The ends are then bent together, cut off square and rubbed on a board until they form a soft, even straw brush. The wisp should be workerl forward and backward well into the coat, so that full advantage may be obtained from the friction. After finishing with the wisp the coat should be laid flat.
Hand rul)bing is beneficial. Wlien an animal has had very hard, exhausting work his legs should be hand rubbed and afterwards ])andaged, taking care that the bandages are not tight. An exhausted animal should also be given stimulants and warm gruel.
personal supervision, see that the grooming is properly done.
No horse or mule should be considered in order until he is thoroughly clean, his mane and tail brushed out and laid flat, his eyes and nostrils wijied or washed, and hoofs put in order.
At each stable the feet and shoes are carefully examined. Aninuiis requiring shoeing are reported to the chief of section, who notifies the stable sergeant.
with warm water and castile soap.
Teasing in grooming should not be permitted. It is a bad practice to attempt to make an animal submit to rough or harsh grooming. To do so means that he will be provoked into kicking, striking, or biting, and perhaps confirmed in these bad habits. If he objects to the use of the brush or currycomb, the hand or cloth should be gently used instead. Careful work will usually win the animal into submitting to the proper use of the grooming tools.
The object of grooming is not merely to clean the coat. The skin nuist be rubbed and massaged to keep the animal healthy and in condition. An abundance of friction applied to the skin when the horse returns from his work is of special value in keeping him healthy and fit.
Quick grooming is to be encouraged. Under ordinary conditions a horse or mule should be thoroughly groomed in 20 minutes. On the other hand, at least that much time should be devoted to him. Each section leader, after the necessary time has been devoted to grooming and after he has made a thorough inspection of every animal in his section and finds them all satisfactorily groomed, 'reports to the officer in charge: First {such) section in order. The officer, after making an inspection, may, if the grooming is satisfactory, permit the section leader to dismiss the men.
388. To confirm recruits in a thorough and systematic method of grooming and to impress upon them the amount of time to be ordinarily devoted to the different parts of the animal they are required to groom by detail during their instruction.
To groom by detail the instructor causes the men to stand to heel and commands: 1. By detail, 2. Commence Geooming. Clean and brush front legs from the knees down, rubbing luider the fetlocks and around the coronets with the brush and hand ; time, 2 minutes. 3. Chaxge. Same as at second command, the hind legs from the hocks down ; lime, 2 minutes. 4. Change, On the near side, with currycomb and brush, groom neck, shoulders, arm, elbow, back, side, flank, loins, croup, and the hind leg to the hock ; time, 4 minutes. 5. Change. First on the near side, after finishing upon the offside, groom chest between the forelegs, the belly, and between the hind legs ; time, 3 minutes. 6. Change. Same as 4, on the offside ; time. 4 minutes. 7 Change. Brush head, ears, and throat ; with the hand rub the throat and between the forks of the lower jaw ; time, 1 minute.
9. Change. Brush out the tail ; time, 2 minutes. 10. Change. With the grooming cloth, or with a damp cloth or sponge, if the parts are foul, wipe out the eyes and nostrils ; wipe the muzzle, dock, sheath, and up between the hind legs ; time, 2 minutes. 11. Change. Clean out the feet ; time, 2 minutes. 12. Change. Complete any unfinished work. 13. Cease Grooming. 14. Stand to Heel.
389. To judge the cleanliness of an animal, the hand may he passed the reverse way of tlie liair to cret a view of the skin. When the points of th.e tinG:ers are run firmly against the set of tho coat lines of j?ray are left on the coat of a dirty skin and tlie points of the finwrs are covered with scurf. Between the branches of tlie under jaw. under the crovrnpiece of the halter, at the bends of the kness and hocks, "under the belly and lietween the forelegs and thig:hs are the places usually nes'lected wlien the v/ork is not tlwrough and which should be looked at in the inspection.
390. Animals should never be hurried in turning around in their stalls. Should the stalls or driveways be covered with ice or be otherwise slippery, sand or litter should be sprinkled on them.
391. Horses are particularly terrified by fire. Should a fire occur in the stables tliey must i>e led. backed, or ridden out of tlie stable. If they are unwilling, a coat or gunny sack should be thrown over their eyes. Care should be taken that they do not break back into the stables.
392. The lieutenant in charge should make it a point to visit the stables occasionally at odd times of the day. The habits and peculiarities of animals may be rauch better studied when the men are away than when grooming is going on.
All animals should be fed three times a day — at reveille, in the middle of the day. and at night. This rule must be rigidly enforced on the march, the noon grain being carried on the animal or in the Magon.
The forage ration for a horse is 14 pounds of hay and 12 pounds of oats, corn, or barley. For a mule it is 14 ]>ounds of hay and 9 pounds of oats, corn, or barley. To each animal 3 pounds of bran may be issued in lieu of that quantity of grain. A dpsirnble (usrribution of the grain ration is, for a horse which
is getting 12 pounds per day, 3 pounds in the morning, 3 or 4 pounds at noon, and the rest at night. Hay, as a rule, is not fed in the morning : about one-third of the ration should be fed at noon, except on the march, and the remainder at night,
394. A bran m.ash acts as a mild laxative anrl should be fed once or twice a week to stabled animals, A little dry bran mixed with the oats is of value in compelling more thorough mastication and prevents greedy animals from bolting their grain. In spring or early summer the animals should be grazed daily when practicable. A lump of salt should be kept in each manger.
Before feeding hay it should be thoroughly shaken out with a fork so as to get rid of dust and seed : it is also advisable to moisten the hay before feeding it. The grain, if possible, should be run over wire screens or allowed to fall through the air to remove dust.
is certain that the animals are thoroughly cool.
Never feed grain to a horse when heated or fatigued. Grain is a highly concentrated food that requires high digestive power. Abnorn.al temperature impairs the power of the digestive organs. If the animal has been worked to the point of fatigue, all bodily functions are for a time injuriously affected. For that reason he must be rested and his normal digestive power restored before concentrated food of any kind 's given to him. ( >a the other hand, hay, being a bulky food, will not hurt a ii')]'se, however heated or fatigued he may be.
In the morning feed is usually placed in the manger at or herore reveille. The noon feed of hay is tisually placed in the nmnger while the organization is at drill, but the grain is not fod until the animals are thoroughly cool. Tlie evening feed is placed in the mangers after the stables have been thoroughly policed for the night.
395. Immediately after a full feed the stomach and bowels are distended. If hard work is given at once, they press against tlio lungs and impede their power of expansion, thus leading to lildwing and distress. Fast work should therefore be avoided alter a full feed. Moreover, though such work rarely results
in colic, it interferes with digestion to such an extent that looseness of the bowels occurs and the food passes through undigested and is wasted. Food remains in the stomach about one and onehalf hours. Fast or heavy work should therefore be deferred from one and one-half to two hours after a full feed.
396. All animals do not require the same amount of forage; the amount given each nmst be l)ased, therefore, upon his individual requirements, which should be closely watched by the stable sergeant. AVhen a horse or mule leaves some of his grain his ration should be reduced that amount. The amount to be fed each animal each meal should be chalked up on a small blackboard placed so as to be easily seen by the men distributing the grain. A convenient arrangement is a board about 12 inches high by 4 inches wide divided by two horizontal lines into three 4-inch squares. In the uppermost square should be marked in pounds tlie morning feed of grain, in the center square the noon feed, and in the bottom square the night feed.
When forage can n(^t he obtained grazing should be required at every spare moment, especially early in the morning when the dew is on the grass, but not if it is covered with frost.
All forage should be inspected by the lieutenant in charge to see that ir is up to weight and contract specification,'::. A forage book showing daily entries of all forage drawn, fed. and remaining on hand, together with the number of the public and private animals fed, will be kept by the stable sergeant and checked daily by the lieutenant in charge. All ofiicers should be familiar with the characteristics of good forage and the manner in which it is commercially graded for contract specifications. To obtain this knowledge olhcers should be encouraged to visit large commercial stables.
Barley possesses a husk so tough and indigestible that it should always be crushed before being fed, else a very great part of its nutrient value is lost.
Sudden changes in food are to be avoided. The digestive organs are frequently unable to accommodate themselves to a sudden change and scouring, constipation, or colic may result. If sudden changes become necessary the ration of the new feed
pounds per cubic foot.
Tlie standard bushel in the United States contains 2,150.4 cubic inches. A cubic yard contains 21.69 bushels. A box 16 by 16.8 by 8 inches holds 1 bushel ; a ])ox 12 by 11.2 by 8 inches holds half a bushel ; a box 8 by 8 by 8.4 inches holds 1 peck ; a box 8 by 8 by 4.2 inches holds one-half peck or 4 quarts.
397. Give the animal an opportunity to drink before leaving the picket line or stable and before putting the bit in his mouth. Animals must be watered quietly and without confusion : the manner in which this duty is performed is an indication of the discipline of a command.
They are to be led to and from water at a walk. This must be carefully explained j to the untrained man who thinks, because an animal puts up i his head to get his wind after his first fill, that he is fi.nished. i In the field or on the march the watering is from the most j convenient running water ; in garrison it is usually from troughs,
the chill to pass off.
Watering is under the immediate direction of the stable serI geant in garrison and the section leader in the field, but if they , are liable to meet those of other commands at the watering ; place a commissioned officer should supervise 'this duty.
All animals should be watered before feeding or not until two hours after feeding. Ordinarily they should be watered twice a day; in hot weather three times a day. In very cold w^eather once a day. about noon, is sufficient. A horse will rarely drink freely very early in the morning.
If a mounted command is to march a long distance without water, so that it will bo necessary to camp on route, the animals are fed and denied water until ,1ust before starting, when they are permitted to drink freely. The command marches in the afternoon and does not encamp until it has accomplished at least half of the distance and moves early next morning to reach water.
Watering the horses on the march depends in a great measure upon the facilities to be had. If nothing is known as to the country over which the day's march is to be made, water call should be sounded shortly before leaving the camp and every horse given an opportunity to drink. As many animals, however, will not drink at an early hour, or until after exercising, the horses should be watered at the first opportunity. On severe marches frequent watering is of great benefit.
Except as directed in paragraph 369, never water a horse when heated unless the exercise or march is to be resumed immediately ; if the exercise or march is to be resumed at once, water will be of the greatest benefit to the horse, no matter how heated he may be, but a horse should not be called upon to do fast work for at least half an hour after a big drink.
All officers must understand the principles of proper shoeing and must supervise the work of the horseshoers, being especially careful to see that the knife is not used improperly.
corporated :
The foot should be prepared so that it will approximate as nearly as possible to a state of nature, and only such trimming is allowed as is absolutely necessary for the purpose of fitting and securing the shoe.
therefore, weakens them and prevents them from performing their function. The practice of using the Icnife to trim the bars or to cut a notcli at the junction of tlie frog and bar at the heel (called " opening the heel " in civilian shops) always tends to produce contracted feet.
the nipper.s.
^^■ith a Hat foot it is frequently necessary to remove a part of the outer ed^e of the wall in order that the nails may be driven in the vdiite line, where they belong. This is the only case v.-here it is permitted to rasp the outside wall. The outer coating of the wall and the layers of dead horn on the sole and frog serve to retain the moisture in the hoof.
circumstances.
V,'hen shoes are left on the feet too long, corns and other ailments are the result. Ordinarily a shoe should be replaced at least once a montii. The lightest shoe that will last for this time is the best shoe. It should carefully follow the form of the foot, or, if the foot is broken, the shoe follows the original form of the foot. Its length is regulated by the bulb of the frog.
The ground surface of the shoe sliould be level and smooth, except for use in snow, v\heu the ground surface should be concaved to prevent balling. That portion of the upper surface which presses against the bearing surface of the foot must be level, smooth, and accurately shaped to support it. and when the upper shoe surface is wider than the bearing surface the inner edge must be concaved to avoid excessive sole pressure. This is one of the most important requisites of correct horseshoeing. Concussion of the sole against the inner edge of the upper shoe surface invariably produces soreness.
399. One side of the shank of a horseshoe nail is flat. The other side is concave and also has a bevel near the point. This bevel, as it enters into the horn, forces the point of the nail in the direction of the other, the flat, side. Therefore in driving a nail always hold it with the Hat side toward the outside edge of the shoe.
from the bottom of the hoof.
400. In garrison, at the discretion of the colonel or of the commanding officer. th(> animals may be left unshod, but shoes will bo kept ready for each animal.
7. Arc the heels of the shoe correct in width and thickness and are they properly rounded, without sharp edges or points? Is their length even with the bulb of the frog?
or both nostrils of an animal it must be immediately reported.
To prevent contagion to man or beast, an animal that shows any decided symptom of glanders is to be isolated at once and confined or tied up in some locality where no other animal can approach him.
! 404. A glandered animal should be killed as soon as possible. I The stall in which he stood is torn down and all the woodwork I burned and the ironwork disinfected, or otherwise it is closed, ' and must remain empty until the rack, manger, and every f p;irt of the iron and v/oodwork, as also the vessels used in I watering and feeding and his saddle antl bit, have been three I or four times thoroughly washed with a 5 per cent solution of
carbolic acid or a 1 to 1.000 solution of corrosive sublimate; all parts to which the latter has been applied should be thoroughly scrubbed with hot water to remove all traces of tlio poisonous salt. The application of a lime wash to all the stalls, after complete disinfection, will be desirable. Small articles, such as bits, etc.. can be disinfected by keeping them immersed for a half hour in boiling water. All articles of little value that have been used with a glandered horse, such as halters, bridles, horse cloths, saddle cloths, blankets, nose bags, currycombs, brushes, etc., should be destroyed.
Stables occupied by infected or suspected horses should be disinfected daily by washing exposed surfaces with a 5 per cent solution of carbolic acid, and nose bags, halters, buckets used for drinking water, etc.. should be carefully washed with the same solution or with boiling water.
DRESSINGS.
Absorbent cotton: i pound, for eye pads. Antiseptic gauze : 1 package, for dressing of wounds. Oakum : 3 pounds, to be used in dressing wounds. Red flannel bandages: 1 dozen.
trained horse and to improve a badly trained one.
5. He should have a practical knowledge of the care of horses, both iu garrison and in the field ; he should understand how to detect and treat the minor ailments to which they are liable; and he should be a good groom.
GENERAL PROVISIONS.
407. For the preliminary exercises the horses are saddled and equipped with the snaffle bit only, saddles stripped. Spurs are not worn. These exercises are conducted at first in a riding hall or on an inclosed course out of doors.
HORSE EQUIPMENT.
408. The instructor indicates the different articles of horse equipment, instructs the men in the nomenclature of the various parts, and explains the use of these parts.
TO FOLD THE SADDLE BLANKET.
409. The blanket, after being well shaken, will be folded into six thicknesses, as follows: Hold it well up by two adjacent corners, the longer edges vertical ; double it lengthwise, so the fold will come between the " U " and " S," the folded corner in the left hand ; take the folded corner between the thumb and forefinger of the right hand, thumb pointing to the left; slip the left hand down the folded edge two-thirds of its length and seize it with the thumb and second finger; raise the hands to the height of the shoulders, the blanket extended between them ; bring the hands together, the double fold falling outward ; pass the folded corner from the right hand into the left hand, between the thumb and forefinger, slip the second finger of the right hand between the folds, seize the double folded corner; turn the left disengaged corner in and seize it with the thumb and forefinger of the right hand, the second finger of the right
I hand stretching and evening the folds ; after evening the folds, i grasp the corners and shake the blanket well in order to i smooth the folds ; raise the blanket and hold the upper edge ' between the chin and breast ; slip the hands down halfway, the
first two fingers outside, the other fingers and thumb of each .hand inside; seize the blanket with the thumbs and first two ' fingers, let the part under the chin fall forward ; hold the * blanket up, arms extended, even the lower edges; retake the
Approach the horse on the left side, with the blanket folded and held as just described ; place it well forward on his back by tossing the part of the blanket over the right arm to the right side of the horse, still keeping hold of the middle points ; slide the blanket once or twice from front to rear to smooth hair, being careful to raise the bhmket in bringing it forward; place the blanket with the forefinger of the left hand on the withers and the forertnger of the right hand on the backbone, the blanket smooth ; it should then be well forward with the edges on the left side; remove the locks of mane that may be under it ; pass the buckle end of the surcingle over the middle of the blanket and buckle it on the near siile a little below the edge of the blanket.
TO SADDLE.
413. For instruction, the saddle may be placed 4 yards in rear or in front of the horse. The stirrups ai'e crossed over the seat, the right stirrup uppermost ; the cincha and cincha strap are crossed above the stirrups, the strap uppermost.
viously explained, the instructor commands: Saddle.
Seize the pommel of the saddle with the left hand and the cantle with the right ; approach the horse on the left side from the direction of the croup and place the center of the saddle on the middle of the horse's back, the front end of the side bars about three fingers' width behind the points of the shoulder blades ; let down the cincha strap and cincha ; pass to the right side, adjust the cincha and straps and see that the blanket is smooth ; return to the left side, run the left hand, back up, down the withers so as to raise the blanket slightly under the pommel arch, in order that the withers may not be pinched or jtressed upon; take the cincha strap in the right hand, rem U
under the horse and seize the cincha ring with the left hand, pass the end of the strap between the ring and safe and through the ring, then up through the upper ring from tlie outside; if necessary, make anotlier fold in the same manner.
McClelland saddle.
The strap is fastened as follows: Pass the end through the upper ring to the front and seize it with the left hand ; place the fingers of the right hand between the outside folds of the strap ; pull slQwly from the horse with the right hand and take up the slack with the left ; cross the strap over the folds, pass the end of it, with the right hand, underneath and through the
Another method of fasteuing the cincha strap is as follows: Pass the end through the upper ring to the rear; seize it with the right hand, place the fingers of the left between the outer folds of the strap; pull slowly from the horse with the left hand and take up the slack with the right ; pass the end of the strap underneath and draw it through the upper ring until a loop is formed ; double the loose end of the strap and push it through the loop and draw the loop taut. The free end should then be long enough conveniently to seize with the hand.
should be a little looser tlian the cincha.
In saddling the horse the cincha must be tightened gradually, and not with violence, a practice that if persisted in renders a horse ill tempered and mean in saddling.
FITTING THE SADDLE.
414. Great care must be taken in the fitting and adjustment of saddles to prevent sore backs. There are six axioms in saddle fitting:
To fit the saddle: 1. The saddle, without blanket, is placed In its proper position on the back. It should be noted whether the upper or lower edges or the front or rear of the 5?ide bars gouge into the back at any place. If this occurs, or if the saddle when lifted from the back a distance corresponding to the thick-
ness of the blanket otherwise fails perceptiblj' to conform to the outlines of the back, the test and remedy described below (5) should be made and applied.
2. The existence of wither pressure is determined by blanketing and saddling the horse and placing an assistant in the saddle. The hand is run over the top and along both sides of the withers beneath the blanket. To make the test effective the man in the saddle should lean forward, and the examiner should not be satisfied with anything less than the introduction of his entire hand.
3. It is noted that the central line of the back and also that the loins bear no weight even when the assistant in the saddle leans to the front, rear, or either side.
4. To determine if the blade bones have unhampered movement, the hand is passed underneath the blanket from the front until the play of the shoulder blade can be felt. The fore leg is raised and advanced to its full extent to the front by an assistant while the hand is in this position. If this can be done while the man in the saddle is leaning forward without pinching the fingers between the side bars and the shoulder blade, the fit in this respect is satisfactory. The test should be made on both shoulders. If the fingers are pinched, the blade bones will also be pinched and the action of the horse restricted. To correct the diflaculty the saddle must be raised, assuming that it is at the proper place on the back, by placing under it a greater thickness of blanket or by attaching pieces of felt under the side bars.
5. To ascertain whether the pressure of the side bars is evenly distributed the saddle is ridden for half an hour or more. On completion of the ride the saddle is carefully un girthed and lifted from the blanket without disturbing the latter in any way. The blanket will be found to bear the imprint of the side bars, and an examination of this depression will show at a glance whether the bars press evenly from top to bottom and from front to rear. This examination must be made quickly, as the elasticity of the blanket soon causes it to lose the impression of the^ side bars. Any irregularity in the fit of the side bars may be remedied by the introduction of pieces of felt to fill up the spaces between the side bars and the blanket. With very little practice these pieces of felt may be cut to the
required shape and thickness with a very shai-p knife. Some edges will need to be as thin as a knife edge ; other parts may require the addition of more than one thickness. After determining where these pieces of felt are to rest, they are attached to the side bars with glue and bound in place* by sheepskin tacked to the side bars. The most radical alterations in the fit of the side bars can be effected in this manner. The method is simple and quick and can easily be performed by the average saddler.
6. The cincha should be sufficiently tight to keep the saddle in its place and no tighter. Generally speaking, correct cinching has been obtained when the flat of the hand is easily admitted under the quarter ring safe. With most horses, after exercising for a while the cincha will be found too loose and should be taken up.
A tight cincha restricts the animal's breathing, and also brings too much pressure upon and strangles the tissues. Especially is this apt to be the case under the quarter and cincha ring safes, when strangulation soon causes lumps, puffs, and sores,
7. Care is taken that the quarter straps are so adjusted and the cincha so selected that the cincha ring safe will be a sufficient distance from the quarter ring safe to avoid pinching and galling the skin between them.
Stand on the left side of the horse ; unbuckle and remove the surcingle, if in use; cross the left stirrup over the saddle; loosen the cincha strap and let down the cincha; pass to the right side, cross the right stirrup, then the cincha over the saddle; pass to the left side, cross the cincha strap over the saddle ; gi-asp the pommel with the left hand, the cantel with the right, and remove the saddle over the croup and place it in front or rear of the horse as may be directed, pommel to the front ; grasp the blanket at the withers with the left hand and at the loin with the right, remove it in the direction of the croup, the edges falling together, wet side in, and place it across the saddle, folded edge on the pommel, marked side of the blanket upper-
Halter briciie, model ol lyli
head, letting them rest on his neck ; take the crownpiece in the right hand and the lower left branch of the curb bit in the left, the forefinger against the mouthpiece ; bring the crownpiece in front of and slightly below its proper position ; insert the left thumb into the left side of the mouth above the tush; press
upon the lower jaw, insert both bits by raising the crownpiece, then with tlie left hand draw the ears gently under the crownpiece, beginning with the left ear; arrange the forelock, secure the throat latch and the curb chain, take care to adjust them properly.
The bridle with snaffle bit only is put on in a similar manner. A bridle with curb bit only is not permitted to be used on the horses of individually mounted men. The curb when used alone is a powerful instrument requiring such dexterity in its use that only an expert horseman on a perfectly trained horse is capable of using it with sufficient delicacy and discretion to obtain perfect control without injuring the horse.
A horse quickly resents and is easily frightened by abrupt or sudden movements about his head. Bridling should, therefore, be done in a most deliberate and careful manner. The ears are especially sensitive, and extreme care nuist be used in drawing them under the crownpiece and into their place. A reliable test that a horse has not been mistreated in bridling is that he permits, without sign of fear or resentment, the gentle stroking of his ears.
417. Except in the field, or when equipped for field service or when the duty is such as to make it necessary to tie up a horse, the halter is taken off before bridling, the reins being first passed over the neck.
If the halter is not taken off, the halter strap is tied in the left pommel ring, or, if the horse be not saddled, around his neck. AVhen the halter is to remain on, care should be taken that the halter rope is untied from the manger before attempting to bridle a horse that is liable to pull back.
TO FIT THE SNAFFLE BRIDU:.
418. 1. The cheek straps are adjusted so that they are of even length and so that the snafTle rests easily in, but does not draw itp the corners of the mouth. A mouthpiece that is too low strikes the tushes and makes them sore ; one that it too high causes the horse discomfort and makes the corners of his mouth sore.
it causes the same trouble at the base and sides of the ear.
3. The throat latcli is bucliled loosely, being only sufficiently tight to prevent the crownpiece from slipping over the horse's ears. Generally speaking, it should permit the entire flat of the hand to be inserted between it and the throat when the horse's head is reined in. A tight throatlatch interferes with the large blood vessels of the neck, with the gullet, and also with the windpipe.
4. The mane and forelock are carefully smoothed out under the crownpiece to avoid causing a sore at the poll and also to present a neat and tidy appearance.
paragraph.
2. A curb bit is selected with a mouthpiece of such length that the branches bear easily against the horse's lips. A narrow bit pinches the lips, while a wide one works about and bruises the lips and the bars. The mouthpiece is best examined for width by inspecting it from the underside of the lower jaw.
3. The cheek straps are adjusted so that the mouthpiece of the bit rests as near as possible opposite the chin groove, but touching neither the tushes nor the corners of the mouth. Generally speaking, the bit should rest about 1 inch above the tushes of horses and about 2 inches above the corner teeth of mares. It rides below the snaffle.
4. The curb chain is fastened outside and below the snaffle. It must be twisted to the right until it lies flat, and it should rest in the chin groove opposite the mouthpiece of the bit. If not properly adjusted it will have a tendency to ride up and press upon the sharp bones of the lower jaw. The curb chain should be loose enough to admit the flat of two fingers between it and the chin groove when the branches of the bit are in line with the cheek straps. When brought to bear, the branches of the curb bit should make an angle of about 45° with the line of the horse's mouth.
Stand on the left side of the horse; pass the reins over the horse's head, placing them on the bend of the left arm ; unbuckle the throatlatch, grasp the crownpiece with the right and assisting with the left hand, gently disengage the ears ; grasp the bit with the left hand, and gently disengage it from the horse-s mouth by lowering the crownpiece ; place the crownpiece in the palm of the left hand, take the reins in the right hand, pass them together over the crownpiece, make two (u- three turns around the bridle, then pass the bight between the brow band and crownpiece and draw it snug.
turned over on the shoulders.
Turn the tails of the coat under about 9 inches, the folded edge perpendicular to the back seam. Fold over the sides to form a rectangle not more than 34 inches across, according to the size of the coat. Roll tightly from the collar with the hands and knees and bring over the whole roll that part of the skirt which was turned under, thus binding the roll.
422. Spread the shelter half on the ground, roll straps underneath, and fold over the triangular part on the rectangular part. Turn under the roll strap edge of the shelter half so that the width of the fold will be 8 inches. Fold the blanket once
across the longer edges and lay the blanket on the shelter half, folded edge within 1 inch of the roll strap edge of the shelter half. Fold the sides of the blanket and of the shelter half inward, width of folds about 11 inches. The shelter tent pole and pins are now laid on the blanket at the edge farthest from the roll strap edge, pole on one si<le of the center line, pins on the other, so as to allow the roll when completed, to bend at the center. Place the underclothing on the blanket. If the coat is to go in the roll, spread it smoothly over the blanket.
Roll tightly toward the roll strap edge, using hands and knees, and bring over the entire roll the part of the shelter half which was turned under, thus binding the roll. Buckle the two available roll straps about the roll, passing them around twice. The roll thus formed should be about 44 inches long.
When the slicker is carried, either with or without the overcoat, it is suspended vertically from the collar, folded two or three times across its short dimension so as to leave the outside of the slicker out, and then thrown across the horse's withers, collar to the left and coat hanging evenly on the two sides. The slicker is then secured in the middle, with center pommel coat strap only.
by saddlebag straps.
The blanket roll, made as prescribed, is strapped to cantle with one short strap and to the saddlebag rings with two long (60-inch) straps; short strap drawn tightly.
The canteen is snapped to right cantle ring.
The lariat, attached to the picket pin by lariat strap, is neatly and tightly wound about the picket pin and secured. The picket pin is then snapped to left cantle ring.
TO STAND TO HEEL.
426. The instructor commands: Stand to Heel. Each man stands at attention 1 yard in rear of and facing his heel post. At the picket line he is 1 yard in rear of and facing his horse.
427. The instructor commands : Stand to Horse. Each man places himself, facing to the front, on the left side of his horse, eyes on a line with the front of the horse's head, so that he can see along the front, and takes the position of attention, except that the right hand, back uppermost, grasps both reins, forefinger between them, about 6 inches from the bit. The reins are on the horse's neck.
428. 1. Prepare to mount, 2. Mount.
At the first command drop the right rein, take two back steps, stepping off with the left foot, at the same time sliding the right hand along the left rein; half face to the right; this should
place the man about opposite the girth; with the aid of the left hand take both reins in the right, forefinger between the reins, and place the right hand on the pommel, the reins coming into the hand on the side of the forefinger and held so as to feel lightly the horse's mount, the bight falling on the right side. Place a third of the left foot in the stirrup, with the assistance of the left hand if necessary ; rest upon the ball of the right foot ; grasp a lock of the mane with the left hand, the lock coming out iDetween the thumb and forefinger.
At the command mount, spring from the right foot, holding firmly to the mane and keeping the right hand on the pommel ; pass the right leg, knee bent, over the croup of the horse without touching him; sit down gently in the saddle; let go the mane, insert the right food in the stirrup, pass the reins into the left hand and adjust them.
POSITION OF THE SOLDIER.
429. The body should be balanced on the middle of the saddle, head erect and square to the front, chin slightly drawn in. Buttocks should bear equally, and as flat as possible, upon the middle of the saddle. Reins come into the left hand on the side of the little finger and leave it between the thumb and forefinger; little finger between the reins, right rein above it; the other fingers are closed, thumb pointing to the right front in prolongation of the forearm and pressing the reins firmly on second joint of the forefinger. The end of the reins fall to the
! front and outside of the right rein. The left forearm is held I close to the body without pressure, the back of the hand nearly I vertical ; the left hand in front of the pommel of the saddle I and as close to the top of the horse's withers as possible, with' out resting on the pommel. The right hand rests behind the I thigh, arm hanging naturally. The feet are inserted in the ! stirrup so that the ball of foot rests on the tread of the stirrup, \ heel slightly lower than the tread.
on a level with the lower part of the inner ankle bone.
The length depends somewhat on the formation of the man ; a man with a thick, heavy thigh requires a shorter stirrup than a man with a thin, flat one. For long distances at the gallop and trot, a shorter stirrup is required than at a walk.
When riding, the stirrups take up, in a measure, the weight of the body in its descent to the saddle, by yielding of the ankles to prevent shock. This action is an easy, quick stiffening of the muscles, which distributes the downward motion between the feet, thighs, and seat.
If. after the man has exercised a shoi-t time at the slow trot, he has a close seat, his leg in proper position, with his heel down, but does not easily keep his stirrup, then Wie stirrup requires shortening.
At the first command seize the reins with the right hand, in front of and near the left, forefinger between the reins so that they come in on the side of the forefinger ; place the right hand on the pommel ; let go with the left hand, grasp a lock of the mane, the lock coming out between the thuml) and forefinger ; take the right foot out of the stirrup; partly disengage the left foot, body erect.
At the command di.wiount, rise upon the left stirrup, pass the right leg, knee bent, over the croup of the horse without touching him ; descend lightly to the ground, remove the left foot from the stirrup and place it by the side of the right, body erect ; let go the mane ; place the end of the reins on the neck near the pommel of the saddle with the right hand, which then seizes the left rein ; face to the left, take two short steps, left foot first. Slip the right hand along the left rein, and take the position of stand to horse,
GATHERING THE HORSE.
432. Before the horse is required to execute any movement be should be given a preparatory signal. This signal should be given at the time of the preparatory command or signal.
Whatever the nioveinent to be executed, the sij^nal is ahxays the same. Its oliject is to attract his attention and to prepare liini for a movement. This is called gathei^infj the horse.
Ha vine: a light pressure of the bit airainst the horse's mouth and a liaiit feel of the lov/or legs against his sides, the rider, in order to gather him. increases the pressure of the lower legs, with heels well shoved down, and slightly increases the tension of the reins. These pressures are increased intermittently until the elastic movement of the horse under the rider indicates that the former has observed the signal.
If when at a halt the horse backs or when marching decreases the gait, the tension applied to the reins has been too great. If when at a Iialt the horse moves forward or when marching he increases the pace or gait, the impulse given him with the legs has not been met or controlled by the reins.
433. Being at a halt : 1. Foncard, 2. March. At the first command the rider gathers the horse ; at the second he simultaneously (1) pushes his buttocks to the front, (2) acts with both legs according to the temperament of the horse, (3) eases the reins by slightly relaxing the fingers, giving the wrist, without losing contact. The aids cease to be active as soon as obedience is obtained.
434. Being at the walk: Halt. The rider sits well (ToAvn in the saddle and gathers the horse; he then simultaneously (1) closes the fingers on the reins, bending the wrist and if necessary moving the hands in and back with the body; (2) slightly increases the pressure of the legs; (3) imposes the weight of his body against the horse's back by convexing his loins backward.
the horse has completed the movement desired.
In order to prevent the horse from halting entirely on the forelegs, the rider must increase the pressure of his legs to induce the horse to engage his hind legs farther under the mass. By convexing his loins and imposing his weight against the muscular activity of the horse's back the rider limits the functionizing of the muscles whicli control impulsion and thus permits the hind legs to participate in stopping or in reducing the gait. It is faulty to lean back in an exaggerated position, because of the tendency to permit the legs and thighs to go forward and to act with a dead pull of the reins on the horse's mouth : if done abruptly, it is painful to a horse and may cause him to halt in a hard and jolty manner.
ESTABLISHING CONFIDENCE.
435. The first object to be attained in elementary instruction in equitation is to establish the confidence of the rider. Many recruits, especially those who have never before had any experience with horses, entertain an instinctive and unreasoning timidity, which can be overcome only by slow, careful, and quiet instruction, involving judgment and tact on the part of the instructor.
Only quiet, gentle, and well-trained horses are used in the instruction of recruits. Effort must be made to avoid falls or other accidents which might spoil the beginner's nerve and so retnrd his progress.
AVith this object in view the beginner is permitted to use the same horse for the fir.st few mounted lessons. "When it is Seen that he is beginning to understand his mount, horses and riders are changed, usually with each lesson, and the training of a soldier should be considered incomplete and unsatisfactory until the average animal goes quietly and pleasantly with him at any gait.
For the first few lessons, both as a measure of security and to avoid weariness, stirrups should be used. In some cases greater security is also afforded if the stirrups are connected by a strap passing under the horse's belly and of such length thai the man's knees are not drawn away from the saddle. The
strap saves falls, because it prevents the rider's legs from flying out in any direction ; and the contidence it instills enables him to acquire balance more quickly.
Later lessons, ])oth for the purpose of acquiring confidence and learning balance, must include riding without s:.irrups. Confidence is also imparted through riding without reins. This is one of the best ways for a beginner to acquire a good strong seat, which is independent of the reins. Fixity of the seat helps 1o produce good Imnds.
The early mounted lessons are conducted at a walk. The trot and then later the gallop are taken up as soon as practicable, but not until the instructor judges that the confidence acquired justifies proceeding to the faster gaits.
minutes, or 117J yards in a minute.
The maneuvering trot is at a rate of 8 miles an hour, or 1 mile in 7| minutes, or 234 J yards a minute. For purposes of individual instruction the rate of the trot may be diminished to the rate of G or 6^ miles an hour by the command slow trot. At the command trot out, the rate is 8 miles an hour.
437. The walk is a gait in which the feet are lifted in succession and put down in the order of their lifting. If the right front foot begins the gait, the other feet are lifted in the following order : Left hind, left front, right hind. The walk should be free, easy, and elastic.
438. The trot is a gait at which the horse springs from one diagonally disposed pair of feet to the otlier ; between tlie beats all the feet are in the air. The right front and the left hind are called the right diagonal, the left front and the right hind the left diagonal.
THE GALLOP.
439. The gallop is the most rapid of gaits. It must not be used unnecessarily over long distances, particularly on hard roads, where the concussion on the feet is severe, nor when the saddle is packed. However, when the rapidity of the normal trot is not sufricient the rider, when out alone, would take the gallop in preferenr-e to increasing the speed of the trot.
The horse is said to lend right when the feet on the right side are more advanced than the corresponding feet on the left side. AMien the feet are advanced in the inverse order the horse is said to lead left.
If the horse be leading right, the first beat is marked by the left hind foot, the second by the nearly simultaneous placing of the right hind and left front feet, and the third by the placing of the right front foot. The horse then leaps into the air from, and advances, the right front foot. In leading left the beats are right hind, left hind, and right front, left front.
right, and leads left in turning to the left.
He gallops false when he leads left in turning to the right, or conversely. A horse is united when he gallops right (left) in front and right (left) beliind. He is disunited when he gallops right in front and left behind, or conversely.
The gallop should be begun on the circle, because the feet are then favorably placed for taking and maintaining the proper lead. The horses thus start off more calmly, and the rider is enable to regulate the pace by describing a circle of greater or less circumference.
Dnring the gallop the command at case is frequently given. The riders execute the suppling exercises which htivo been indicated as necessary in each case; they abandon themselves completely to the motion of tlie horse, and thus acquire ease and flexibility. Prolonged periods at the gallop on calm and free-moving horses are most favorable for easily obtaining this result.
440. The mule when hitched is led and maneuvered by means of the Inidle. \Vhen leading the mule, the soldier takes position on his near side, holding the reins near the bit in the right hand and the loose end of the reins in the left hand.
To gather the mule, the riglit hand is raised slightly until it touches his lower jaw. The mule must always be gathered before moving, l^efore halting, and before changing gait or direction.
The mule must never be faced or threatened by the man leading him. He must l)e taught by quiet and gentle treatment to effect all changes of gait and direction evenly. He should not be turned short, but on the arc of a circle of 2 yards' radius. He should be led with a loose rein and urged on, if he lags, from the rear.
as follows :
On the right-hand heelpost the bracket will be placed to receive the reins, bridle, breast strap, and traces. On tlie lefthand heelpost the bracket will be placed to receive the breeching and saddle.
TO HARNESS.
443. The instructor causes a mule to be harnessed; points out and names the various parts of the harness and explains their use. He then has the harness taken off and replaced on the brackets.
The harness being on the heelposts, the instructor causes the men to stand to heel and commands: Hakness. At this command each driver places the harness upon the mule in the folio v.ing order :
Saddle and hrcecMng. — The driver grasps the saddle in his left hand, slips his left forearm under saddle, grasps the breeching in his right hand, and approaches the mule on the near side ; places the breeching on the mule gently and lifts the saddle into position on the mule's back, being careful that the turnback is tight. He then tightens the belly band.
Breast fit rap and traees. — The driver grasps the neckband with the left hand, the two traces being folded over and held in the left hand. He then releases the halter shank from the manger and passes it through the opening between the breast strap and the neckband. The neckband is then passed over the mule's head and placed in position with shoulder straps so adjusted that the breast strap will remain horizontal.
the check rein to the saddle.
If the halter has not been removed, the halter shank should be passed around the mule's neck and fastened. The driver then takes post on the near side of the mule, grasping the lead rein 6 or S inches from the bit and holding the shank of the lead rein in his left hand.
P^ach driver leads his mule to the front of the shafts and backs him into position. The shafts are raised and inserted in the shaft loops. He then buckles the shaft-loop straps suffi-
side is similarly fastened.
Quarter straps. — The n.ear-side quarter strap is passed under the trace, between the shaft and the quarter-strap loop, around the shaft, and buckled. The off-side quarter strap is similarly fastened.
Tlie driver then takes post on the near side of the mule and near his head, grasping the lead rein in his right hand, with the loose eu'l in his left hand, and remains at attention.
Bridle and checlcrein. — The driver unsnaps the checkrein from the saddle, takes off the bridle ; unties the halter shank from around the nude's neck and holds it in his left hand.
Breast strap and traces. — The trace on the near side is pulled forward out of the loin loop and is passed over the breast strap between the two shoulder straps. The trace on the offside isarranged in a similar manner. The breast strap is raised with the left hand and the neck band passed over the mule's ears. The left forearm is passed under the neck band and the mule is then tied to- the manger.
Saddle and hreeching. — The bellyband is loosened. With the left hand under the forward edge of the saddle and the right hand grasping the hip straps the harness is lifted upward and to the rear clear of the mule. The left forearm is slipped under the saddle, and the breeching is brought forward so that the back strap can be grasped by the left hand. The harness is nov/ replaced ou the bracket.
Dutch collar, saddle, and breeching.
When the soldier has become familiar with harnessing and unharnessing he should be thoroughly instructed in the fitting of harness. Tliis subject should be given proper attention, everything being done to impres's upon the soldier its importance.
its normal position.
A checkreiu that is too tight puts the animal at a disadvantage when he is required to pull a heavy load ; in addition, it wili cause him to fret and is apt to make him vicious.
Breast strap. — The breast strap should be so fitted by means of the shoulder straps that it will remain horizontal and Uear on the fleshy part of the mule's breast. If the breast strap is too low it will make the animal awkward in movement.
Saddle. — The saddle should be placed in rear of the withers approximately 4 fingers' breadth from the shoulder blade. In no case should it be placed so that it will come in contact with the backbone or withers.
Breeeh strap. — The breech strap should be so adjusted that it will bear quickly when the mule is required to check the movement of the cart, but will not impede his movement while pulling. This adjustment is very important. It can best be made by watching the mule while pulling and tightening the
Hip straps. — The liip straps sliould be of such length that the breech will bear Just below the point of the buttocks. The lower the breech strap is adjusted, the less does it assist the mule in checking the movement of the cart.
Traces. — The length of the traces must depend in great measure on the size of the animal, and for this reason no set rule can be given. Care must always be taken, however, to place the mule as near his load as possible and to see that the traces form a straight line from the breast strap to the singletree.
CARE OF HAKXESS.
448. Breaks and rips in harness should be repaired without delay. Temporary repairs may be made by the driver, but he should take the harness to the saddler for permanent repairs as soon as possible.
Harness must be kept clean and in good condition no matter how often the conditions of weather require it to be \yorked on. At least once each week every harness should be given a general overhauling, parts separated, buckles and fastenings disengaged, and all leather and metal parts cleaned with harness soap and rubbed.
Wlien leather shows signs of drying out it should be given a light coat of neat's-foot oil. The oil can be rubbed in on the rough side of the leather so as to discolor tan leather but slightly.
Leather must not be soaked with water. Just enough water is used with saddle soap to produce a lather. Leather may be cleaned with castile soap and then coated with the lather of saddle soap. Saddle-soap lather should be left on, and after about 15 minutes the leather rubbed with a dry cloth.
BLANKET.
450. The blanlcet should, if possible, be kept dry and free from sand, caked dandruff, and hairs. It should be frequently shaken out and well switched, if necessary, to restore its pliabilit.\- and remove dust and hair. In warm weather, when the animal sweats freely, a fresh, clean bearing surface on the blanket should be placed next to the back.
It is not a good plan to dry the sweat-soaked surface of a folded blanket in the sun and put this dried surface next the back the following morning. Sucli drying hardens the dandruff mixed with sweat and dust that is always present, and makes this part of the blanket rough and hard. It is preferable to double the sweat-soaked folded blanket on itself, so it will remain moist and soft.
Care must be taken that tlie blanket is free fi-om sand and dust and that the mane lies properly. The blanket is placed, with no wrinkles in any of its folds, in position in such a manner that it will not disturb the mane or ruffle the hair of saddle bed.
UN SADDLING.
451. On arriving in camp and having dismounted, the cincha is eased off about 3 inches and the bearing of the saddle changed l)y moving it to rear or front at least an inch. The saddle is left on the back for 10 minutes to enable the almost bloodless skin beneath (caused by weight of rider and pack) and the tired saddle muscles to regain to some extent their lost tone, while the rider attends to the bridle and halter and the religious duty of closely examining the feet for loose shoes, rocks, nails, bruises, thrush, and interfering sores. The saddle is then removed, the blanket turned over, and let so remain In place until the back has dried.
Never remove the saddle and blanket in such a way as to expose a wet back either to the hot rays of the sun or to a sudden cooling-. The pressure of the saddle restricts the blood supply and so weakens the tissues of the back. In this condition a hot sun more readily burns or inflames the skin, while a sudden cooling contracts the blood vessels and prevents the proper return of the blood to nourish the tissues. In either case sores and swellings may result.
rubbed and massaged to dry it and restore the circulation.
452. If any dry spots are noticed on the sweaty skin while the blanket is being turned over, they are inflammations of the skin, produced by unequal distribution of weight, and are liable to puff up later if not attended to. Their location should be marked well and not neglected. When the back is dry the blanket is removed and the back taken care of. The spots referred to are massaged vrell from front to rear, the saddle bed bathed with clean water, dried, and let the animal roll if he will. Should small swellings appear, however, the blanket is kept in place until a soaking wet gunny sack is procured. The blanket is then removed and the swelling vigorously massaged ; tlie wet folded gunny sack pack is tlien put over the back and secured. The animal is not allowed to roll if it can be avoided, and the pack is kept wet during the night. In the majority of cases the animal will be ready for careful saddling in the morning.
453. Should a gall have been produced the place should be bathed and disinfected with a creolin or carbolic-acid solution (1 ounce to the quart of water), the spot protected from the Hies, cold packed if necessary, and the animal led until nature effects a cure. Close attention to cleanliness, disinfection, and stimulation of the wound will hasten the process. A solution of aloes or alum in water (one-half ounce of either to a pint of water) as a stimulant may be used.
produced if the rider is not a careful one.
Irrespective of the fit of the saddle and condition of blanket, the things that cause galls and " bunches " most frequently are carelessness in balancing and securing the pack, a lounging, shifting seat, and a sloppy method of handling the reins, inattention to proper cinching, unequal length of stirrups, neglect
BITTING.
455. The inside of the lower jaw is often injured by ignorant liandling of the curb rein. These injuries appear above the bridle teeth or " tusks " and present inflamed places that sometimes exhibit ulcers. Quite often the bone is splintered. Less frequently the under part of the jaw, in the vicinity of the curb groove, is bruised and perhaps fractured more or less completely.
456. These injuries should be treated by putting the animal on a simflle at once and placing it high enough in the mouth to avoid any pressure on the injured parts. If ulcers appear, they are washed out frequently with a saturated .solution of boracic acid. When the bone is splintered it is usually a serious nuitter and requires the services of a trained veterinarian.
See to it that the vehicle is well greased.
Vehicles in column should never be stopped when it can possibly be avoided. The adjustment of the load or the picking up of articles dropped off should be done without stopping, if at all possible. Stopping an entire column for any but a serious cause is inexcusable, and is a form of carelessness or willfulness that should be punished.
steady pace without cracking the whip or coming in too close.
"When followed by other vehicles, or when driving in a place where other vehicles are liable to be following, always signal before slackening the gait or changing direction. Signals are made by liolding the hand or whip vertically for slackening and horizontally for turning.
459. The driver should sit firmly Imt comfortably in the seat, body erect without stitYness, and elbows close to the sides, with the point almost touching the hips.
HOLDING THE REINS.
460. Place both reins in the left hand, the left rein over the forefinger and the right rein under the middle finger. Thus you liave two fingers between the reins. The reason for this is that it giyes much more scope for play of the wrist on the mouths than if you only have one finger between the reins. The thumb shoidd point straight to the front and should not be pressed down on the reins. The forefinger will be held well out, pointing to the right rear. This will keep the rein close to the knuckle, and the pair may be easily moved from side to side by simply turning the bfick of the hand up or down ; up for left turn and down for right turn.
The right hand is known as the whip hand and, in addition to holding the whip, is used to assist the left hand in shortening the reins by pulling them through from loehind the rein hand.
is often caused by neglect of this precaution.
In all movements from a halt each driver gathers both of his horses just before they are to move; if in march and the gait or direction is changed, both horses are gathered just before they change gait or direction. Care should be taken that both the horses move off together and change the gait at the same time.
In starting a cart or wagon it is especially important that both the horses of the team should throw their weights into the collars gradually but simultaneously. Unremitting attention is required upon the part of every driver in order that each horse shall at all times do its proper share of the work.
By observing these important rules, a team is enabled to pull steadily together, and the horses are not fatigued by jerks, which make them balky, gall their shoulders, and break the harness.
TO START.
462, Feel all the animals' mouths, and, if necessary, give' them the word to go, dropping the hand to them at once until the vehicle is fairly off. The wheelers ought to start the wagon, and this can be effected by touching them with the whip if they require it. It is never safe to start without having the whip in the right hand ready for immediate use. The whip is to the driver what the leg is to the rider ; that is, it keeps the team up to their bits. As* soon as the team is going straight, take the right hand off the reins, at the same time keeping it close by ready for any emergency.
PULLING ur.
463. To pull up, shorten all the four reins by passing the left hand up to the right or else by pulling all the four reins through from behind, as before explained : then., having the right forefinger on the left lead rein, the middle finger on the left Avheel. and the lower fingers of the right hand on the right reins, pull both hands l)ack toward the body, and if necessary lean back a little.
Should the team be getting the better of you and you find thai: you can not stop it. it will be found a great assistance to place the right leg over all the four reins, as you may be able to stop them by the extra power and leverage by the position of the leg. Of course, it is understood the brake has been applied.
Alter position of bits if the team pulls hard.
Always take a pull at the team to steady it just before you arrive at the crest of a hill, and begin to descend slowly, holding the leaders steady, and with just enough traction to keep their single trees from hitting them.
or the wheelers pulled down.
If, while going down a hill and especially when near the bottom, you find a wheeler slipping on his hocks, do not try to pull him up. but drop the hand and allow the team to go a trifle faster.
465. Constant and intelligent supervision of adjustment of the bearing parts of harness, packs, and saddles is productive of better results than medication in keeping transportation animals in serviceable condition.
Animals in a command lose fle.sh rapidly for the first 10 days of a march, and during this period the adjustment of all parts of the harness, more especially the collars, should be given close attention.
466. Feeding .should be done soon after reaching camp, a little hay being offered first. Animals are watered before feeding grain when possible. Grain is offered immediately after watering, and what remains of the hay for thai day is then placed before the animal. The morning water must of necessity be governed l,)y circumstances. If absolutely sure of water on the road, say one hour after breaking camp, it would be needless waste of time and energy to water immediately before or after the morning feed on the line.
467. Collars of steel, such as those furnished to artillery commands, are preferable to leather for military use, when properly adjusted and cleaned. When improperly adjusted they are inferior to the leather article. Steel collars are adjusted by means of bolts and plates. Leather collars by means of top straps and hames. When these methods will not produce the desired results the use of collar pads must be resorted to. Felt collar pads are not desirable as they soon become stiff and hard.
A collar should fit snugly to the sides of the neck without compressing it, and its bearing surface should rest squarely on the bed of muscles situated on the front of the shoulder. When in position there should be a space between its lower part and the windpipe sufficiently large to comfortably admit the insertion of the open hand, back up, as far as the wrist.
the protection of the top of the neck against rubbing.
To prevent blistering of the top of the neck on' hot, sunny days, it will be found that a wet sponge or a wet piece of folded gunny sack, properly secured to the top of the collar and wetted at intervals, is effective.
The bearing surface of steel collars and neck plates should be washed carefully soon after making camp.. They should never be seoured irifh sand or rubbed with an abrasive substance, for the reason that the steel beneath the zinc platino may be thus exposed. The exposed steel rusts quickly, pits rapidly from the action of the acid sweat, and acts as a rasp would on the soft tissues with which it com.es in continual contact.
The bearing surface of leather collars should not be scraped unless considered absolutely necessary to remove accumulated dirt due to negligence. If scraped, they should be boned smooth and then slightly oiled. Leather collars may bo easily cleaned
vrith a damp sponge. They should be thus cleaned each evening. A careful man \vill not let his collars remain, on the ground overnight, Init will hang them on a wagon pole or put them in some safe place where they will be protected from the rain and the dust of the camp.
468. On arrival in. camp collars are left in position for about 15 minutes. Their weight on the hot. tender skin affords sufficient pressure to prevent the formation of swellings so often observed after the collai- is suddenly removed. Normal circulation will establish itself gradually under collar pressure alone, and the skin of the shoulders and neck will regain its tone and elasticity.
Mter removal of the collar, the shoulder and neck is bathed with clean water ; this removes sand and dust that would otherwise remain in the hair, where it may not be reached by the horse brush.
Animals v/ith narrow, lean shoulders should not be placed in the collar. For these, if they must be harnessed, a breast strap (Dutch collar) should be used.
Care must be taken in putting a collar on a horse that the mane hangs naturally beneath the neck plate. . If the collar is a steel (me, care is taken when snapping it in place to see that the skin of the upper part of neck is not pinched between the ne<.-k plate and the collar itself.
If swellings appear on the shoulders they are massaged to reriiove them and in addition a cold-water pack is applied during the night ; a wet sack properly adjusted and held in place will answer the purpose. If a gall appears it should not be greased, but washed with water and soap, drietl thoroughly, and a weak solution of alum (one-half ounce to a pint of water) or a solution of aloes in vrater (one-half ounce to the pint) applied. If the animal must be worked, a chambered (cut-out) pad is placed over the spot to remove pressure. Greasy ointments serve as a trap for dust and sand, and consequently should never be used.
Leather traces stretch considerably in wet weather. A difference of, lialf an inch in the length of traces will cause trouble on the shoulder of the shorter side. It is also liable to produce lameness due to irritation of extensor muscles. If the point of attachment of the trace to the collar should be too high it will cause a downward pull on top of neck, with its consequent irritation. If too low it will cause the collar to " ride," and nearly all the pressure v/ill be on the point of the shoulders and on the windpipe.
horsemanship of the personnel.
470. The breeching should be fairly loose ; otherwise it is lialile to chafe the quarters and to interfere with the free play of the muscles. It should be taken up, as the animals become thin.
to chafe the soft, thin skin of the under part of the body.
471. Yoke straps should be adjusted with a view to the height of the pair. They should never be permitted to trespass on the bearing surface of the collars.
472. Backstraps should be so adjusted as not to let the saddles ride the withers, but at the same time there should not be sufficient strain on them to cause the crupper to irritate the under part of the tail.
473. BcUyhands and cinchas should never be unduly tiglitened, as they cause cinch sores near the elbow and quarterstrap sores beneath the ring shields.
When a cinch gall appears, the cause is removed, the place kept clean, and a solution of aloes or alum in water applied. Either of these will stimulate the gall and deter insects from alighting on the wounds.
reins are not a necessity.
475. A driving bit sliould be smooth and jointed. It should be so adjusted that it will not lift the corners of the mouth. If placed too high in the mouth, the animal uses his molar teeth to press against it and gains for himself the reputation of a hard-mouthed puller.
The men sliould be taught to beware of thread ends in collar pads and of knots in headstalls, throatlatches. bell-ybands, cinclias. and surcingles, and to be careful that buckles are not turned toward the skin. These readily produce irritations and abrasions and are plain evidence of negligence and carelessness on the part of the rider or driver as well as loose supervision on the part of those superior in rank.
476. To keep his animals in the collar and otf the lead line should be the aim of each driver. This can be accomplished with little irouble. barring accidents, if the harness is kept in proper shape and tit and necks and shoulders are kept clean.
mercial railways is a function of the Quartermaster Corps.
To enable the quartermaster properly to estimate for cars, he should be informed as to the exact number of men and animals and the amount of materiel and equipment to be transported for each separate company and headquarters. Except in theaters of actual operations, the quartermaster must also be given such itemized lists of property and \Yeiglits as will enable him to prepare bills of lading. To assist the quartermaster, each company commander and each headquarters should furnish a list of the numbers and kinds of cars required for the unit.
478. Whenever practicable sleeping cars are provided for the personnel on journeys of 24 hours' or greater duration. Sufficient cars are furnished to provide a section for each three men and for each two officers. In determining the number of cars allowance must be made for employees of the sleeping-car companj' and of the railroad. These employees include a porter for each car, two cooks for each tourist kitchen car, a sleepingcar conductor, and a railroad agent. Each of these employees utilizes one berth.
479. Tourist sleepers usually contain 14 or 16 sections and tourist kitchen cars 12 sections. A standard sleeper has 13 or 14 sections, including the drawing room and stateroom.
480. When day coaches nuist be utilized and the journey is considerable a seat should be provided for each man. On this basis a standard day coach will carry about 30 men.
481. The carts are ordinarily transported in box cars. 40 feet long and 9 feet wide: a car of these dimensions will carry eight gun carts and eiglit annnunition carts, leaving enough free space to facilitate loading and unloading.
water cart make one carload.
483. Harness, officers' baggage, and such of the personal equipment of the men as are not necessary on the journey are carried in a baggage car provided for the purpose.
484. Box cars are provided for forage, annnunition, and other property according to the necessities. Unless the companies are to detrain in the theater of operations, ammunition should be boxed and carried in a special car.
485. Box cars are usually 40 feet in length. The interior cross section is about 9 by 8 feet. The load capacity varies from 40,000 to 100.000 pounds. It is inadvisable, however, to load a car to its capacity, and 40,000 pounds may be asstimed as the load and 2,400 cubic feet as the cubical capacity of the average box car.
486. The weight limits the amount of annnunition and of oats which can be carried in a single box car. Cubical capacity limits the amount of military stores of other kinds, especially hay.
One thousand two hundred pounds, or 100 rations, of oats occupy a space of about 40 cubic feet: 1,400 pounds, or 100 rations, of baleil hay occupy a space of about 120 cubic feet. When access must be had to the forage during the journey, 1.200 rations is a suitable load for a forage car.
487. Animals are carried in stock cars or palace stock cars. If palace stock cars are not available, a box or stock car should be provided for eAch six privately owned officers' mounts.
carry about 20 mules.
488. The amount of baggage, forage, and rations to be taken depends upon circumstances and should be definitely prescribed in tlie order directing the movement ; ordinarily rations and forage sufficient for three days after the completion of the journey is ample. More than this is generally mmecessary and causes delay and congestion in entraining and detraining.
489. When movements from garrison or semipermanent camps are contemplated, ample notice should, if possible, be given so that the necessary arrangements concerning property not pertaining to the field equipment may be made. Not less than 48 hours should be allowed for the orderly transaction of this business.
When sufficient time is not available for these purposes the security and care of such property as is left behind devolves upon the troops remaining in the garrison or camp.
490. The time required for loading each train carrying machine-gun companies depends upon the facilities for loading, and especially upon the amount of equipment and supplies to be carried.
491. Delays and confusion in loading are chiefly due to lack of advance preparation of a definite and rational plan or to failure to follow such a plan during the loading. A common mistake is the attempt to rush the loading by assigning cars so as to begin the loading of all companies simultaneously vrithout adequate facilities or cars therefor. In general, confusion will be eliminated and time will be saved by making up each train complete before spotting it at the loading places. For the storage of cars and the making up of trains ample switching facilities should be set aside. It is especially important that the loading platforms for any one organization be not widely separated. The number of trains which can be loaded simultaneously thus depends upon the available switching facilities. As under .a suitable plan similar cars for the several organizations are loaded from the same platforms, the heavier stores for each organization may be transported to the loading platforms before the departure of the preceding organization. Care must be taken to avoid interfering with the loading and to keep the stores to be loaded on any one train separate from those going on another.
492. Sufficient tags should be kept on hand to mark all equipment not carried in the cars with the men or not otherwise readily identified. The loading of each class of property should be under the immediate charge of an officer, who should list all items going into each separate car^ noting on each list the markings and number of the car.
493. Whenever practicable each company occupies one train with all of its personnel, animals, and materiel complete. It is, however, preferable to have trains of moderate size with good speed rather than long trains with low speed.
Total 13
In making request upon the quartermaster for transportation the necessary sleeping-car section should be specified. The number of cars then depends upon the type of sleeper furnished.
For movements of a few hours in the theater of operations the personnel may have to ride on the flat cars. As in such cases the equipment is limited, the harness and stores may be carried on the flat cars with the carts.
the cars by the mechanics.
The blanket roll of each man is tagged and the rolls of each squad are tied into a bundle. These bundles, together with the officers' baggage, are carried in the baggage car.
Rations and kitchen equipment which will be needed during the journey or immediately upon arrival are placed under the charge of one of the cooks, who sees that they are loaded in the baggage car so as to be immediately accessible.
If the animals will probably be unloaded during the journey, each section leader collects the feed bags belonging to his section and turns them over to the stable sergeant, who makes a memorandum thereof. The stable sergeant sees that the feed bags, necessary grain measures, a few bandages and disinfectants, and stable tools are placed in the center of the forage car so as to be readily accessible.
The men take their packs, slickers, overcoats, canteens, and haversacks or saddlebags with them in the cars. Such arrangements are made as will avoid the necessity for carrying these articles while at work and insure their being properly guarded and Jivaiiable at the proper time.
498. So far as practicable all stores, forage, etc., should be at the loading places before the train arrives (491). Similarly each company, complete with all its materiel, anim.als, and personnel, except those men needed as guards over stores, should arrive, so that the animals may be unharnessed and harness and carts placed convenient to the loading places before its train is spotted.
499. As soon as the animals have been unhitched they should be taken to the vicinity of the place at which the harness is to be loaded and there unharnessed. The two mules are held by a driver designated by the section leader.
When harness sacks are avaUable tlio harness of each animal is packed in its sack, plainly marked (492). The horse equipment of officers and individually mounted men are placed in gunny siicks or. if sacks are not avaihible, wrapped in saddle blankets, plainly tagged. The horse equipments of officers are placed in the baggage car, or, if a separate car is provided, in the car with their mounts. The horse equipment of individually mounted men are phiced in the car with the harness.
The drivers take the animals to a designated place and secure them. If the stables or permanent picket lines are available, they should be secured there and left under the charge of two drivers detailed as guards.
The animals are given a feed of hay. which should have been withheld from them for some hours before. AVhenever practicable they should be watered about one hour before they are loaded.
DOO. All animals having been unhitched and secured, the company falls in, each man carrying his individual equipment or saddlebags, canteen, and slicker. These articles are deposited on the ground and a guard placed over them. The necessary details are made and the loading is started as scon as the cars have been inspected and turned over to the organization.
501. Each train connuander should detail an officer to accompany the quartermaster in the latter's inspection of the cars, made after the train is made up and before it is turned over to the troops for loading.
Passenger cars must be clean, fully supplied with water and ice and sufficiently lighted and heated. Common defects are lack of water, ice. and illumination.
Stock cars must be inspected with special care to see that they are in good order througliout. Common defects are loose boards, rotten flooring, broken fixtures, protruding nails, and filthy condition. These are sources of danger and discomfort to the animals and of loss to the Government. Such cars should be rejected. In time of peace the commanding officer should not hesitate to suspend the movement until proper cars have been provided. In time of war it is usually necessary to be content with what can be obtained. Such repairs as are practicable should be made, and a report should be forwarded setting forth the conditions. '
spected.
502. As soon as the cars have. been accepted they are prepared for loading. The officer detailed to load the animals, accompanied by the stable sergeant and one or more of the mechanics, makes a detailed inspection of the stock cars. All projecting nail points are bent and splinters are removed. The breast bars on the doorways opposite the loading platform are examined, put in place, and the doors themselves securely fastened. Such repairs as may be necessary are made with the material available. The cars should be clean and the floor covered with at least 21 inches of sand or sawdust. In permanent garrison material lor this purpose should be kept on hand. The brake handles of the flat cars should be removed, so that the carriages may be run from one car to another.
503. <3rdinarily a section carr be usefully employed in loading a box car. A noncommissioned officer and about six men should be inside the car to stow the property. The remaining me« pass the packages in.
504. Ordinarily no attempt is made to load more than one vehicle car at a time. Frequently the length of the loading platform will be such that several of the cars must be reached by running the carriages across other cars.
The vehicles are secured with 2 by 4 inch timbers, as follows : Pieces nailed to the floor of the car on both sides of each wheel prevent transverse motion ; in front and rear of each wheel, longitudinal motion ; over the lowest part of the fellows and nailed to the timbers which lie alongside the wheels, vertical motion. All these pieces can be of the uniform length of 9 feet.
505. The necessary timber and nails are furnished by the quartermaster. For each car h)aded with ammunition and gun carts, 432 feet of timber (cut into 9-foot lengths) and 10 pounds of nails are required ; for cars loaded with fleld wagons 270 feet of timber and 8 pounds of nails.
506. As each flat car is loaded the mechanics nail the securing timbers in place. A gun squad should be detailed to bring the timbers and put them in position for nailing.
the wheels that are placed tire to tire.
507. When ample time is available it may be desirable to remove such articles as pauling, lanterns, etc., from the carts and carry them properly paclied in a ])ox car with other stores.
508. The animals should not be loaded until the loading of all carts and stores has been completed. Whenever possible loading pens and chutes to be found at railroad stations should be used. In any case especial care must be taken th.it the animals have secure footing in passing into the car.
For each car being loaded four selected noncommissioned officers, a mechanic, and a squad should be detailed. Two of the noncommissioned officers work inside the car. The remaining noncommissioned officers work at the door of th.e car. Two of the members of the squad collect the halter shanks and .see that they are turned over to the stable sergeant at the forage car. The remaining men assist the noncommissioned officers at the doors. When chutes are available all these men, except the noncommissioned officers, should remain outside the runways until they are called for. When pens and chutes are available the animals are penned by carload lots. A noncommissioned officer and a squad are assigned to work in each loading pen, the remaining men bring the nnimals from the holding pens as soon as the preceding lot has been loaded. As the animals arrive the men in the loading pen remove the halter shanks and pass them to the men detailed to collect them. The gate to the runway Is kept closed until the gangplank is in place, the side gates closed against the car, and the noncommissioned officers in place. Everything being in order, the gate is opened and one of the men leads"^ the gentlest animal in the pen up the runway. The remaining men cause the animals to follow as closely as possible. This is accomplished without shouting or otherwise exciting them. Animals that hold back are slapped or gently struck acro.ss the rump with a halter shank. The noncommissioned officio's inside the car place themselves near the door and keep them quiet by speaking to them. When the first animal arrives one of the noncommissioned officers takes him from the man leading hii'! and leads him to one end of the car. After this the noncommissione<l officers confine themselves to keeping the animals quiet and preventing them from leaving the car. The animals
are thus allowed to pack themselves in the car. It is desirable that as many as practicable be placed in each car not provided with separate stalls. With animals not trained in loading each noncommissioned officer may be assisted in the car by two men whose duty it is to hold the last animal received in place across the car.
The car having been filled, the noncommissioned officers inside the car first put up the breast bar and then leave the car. The gangplank is swung back, the side gates slipped back, and the car door closed. The mechanic fastens the door securely.
509. When loading pens are not available and the animals must })e loaded from a platform similar methods are used, except that all the animals are led into the car. The halter tie ropes are taken off after entering the car and turned over to the men collecting them, as the men who led the animals pass out. In leaving the car the men must be careful to avoid interfering with animals just entering.
or ramps must be improvised.
For loading the carts such platforms or ramps are preferably placed at the end of the cars. For animals the ramp should be well supported, have strong sides, and the bottom provided with cleats to give a secure footing. By taking advantage of shallow cuts and using baled hay, platforms may be readily improvised.
ramps ready prepared on the cars.
511. It is not necessary to wait for an engine each time cars must be spotted during loading or unloading. By uncoupling the cars and distributing 20 or more men along the sides of those to be moved, two or more cars may be readily shifted. Care must be taken to have men ready to handle the brakes and to give signals in such a way as will cause all the men to work together.
512. The animals having been loaded, the men fall in at the place where their equipments were left, secure them, and are marched to the coaches. The assignment of men to particular coaches should have been made beforehand, so that the men may enter without delay.
513. So far as practicable sections are kept together. In each car the senior noncommissioned officer occupies a seat next the door at one end of the car and the next senior, except in the officer's car, a seat next the other door. These noncommissioned officers preserve order and see that no one leaves the car without authority.
The cooks are in the kitchen car or in the car next to the baggage car used as a kitchen. The first sergeant, stable sergeant, supply sergeant, company clerk, and mechanics are in the car with the officers.
Before entering the train the company commander cautions the men not to leave the cars without specific orders; that complaints are to be made to him and not to the train crew ; and gives such other instructions as may be necessary.
The sleeping-car conductor or the porters and the train conductor should be informed as to the orders relative to the introduction of unauthorized articles into the train, and requested to impart this information to their subordinates.
514. The train conductor should be requested to notify the company connnander immediately before any halt of 10 minute.-^ or longer is to occur. During such stops an officer, accompanied by the quartermaster and stable sergeants, the chief meclianic. and one or more mechanics, inspects the stock and flat cars and make any repairs which may be necessary and practicable. When the duration of the stop is considerable, gurirds should be posted on the flat cars.
for exercise, feeding, and watering.
AVhen the journey is to exceed 24 hours, suitable arrangements sliould be made with the railroad authorities for the stop lor feeding. It is desirable that the place for unloading should be selected several hours beforehand, so that the proper notice may be given to the station agent and other railroad officials. In order that delays may not result in its being necessary to reload the animals at night, a station for unloading should be selected that, without unexpected delays, will be reached at about noon.
516. The necessary requirements for a suitable feeding station are : Water and a platform, or, preferably, a chute for taking the animals out of the cars.
dins: in the cars, etc., are also desirable.
517. Before reaching the feeding station the senior noncommissioned officer in each car details a guard to remain in the car, causes the drivers to get out their grooming kits, and cautions; the men tliat the remaining equipment, except pistols, is to be left in the car.
l'l)oii reaching the feeding station the men, except the mess sergeant, cooks, and guards, are notified to leave the cars and fall in at a designated place. Rolls having been called, the drivers are formed separately from the other men.
518. Two gun squads are detailed to assist the stable sergeant in preparing the forage. These men are at once marched to the forage car. The stable sergeant, upon reaching the forage car, gives the halter tie ropes to one of the detail, who. assisted by another man, takes them to the stock cars and distributes them as they are needed. These men are responsible for collecting the tie ropes and turning them over to the stable sergeant when the animals are reloaded.
The stable sergeant causes the remaining men of his detail to put one feed of oats in each feed bag and to distribute one feed of hay at the feeding places.
The feed bags are not taken to the feeding places until the animals have been watered, when all the men assist in this distribution. No attempt is made to give the animals their own feed bags.
519. The supply sergeant, and the mechanics not engaged in unloading the animals proceed, as soon as the rolls have been calleil, to the flat cars, where they make such repairs as may be necessary. Having completed these repairs, the mechanics begin on the stock cars as soon as the latter have been unloaded.
As soon as an officer is available, one is detailed to inspect all this work, to cause any additional repairs that may be necessary to be made, and to superintend the resanding of the cars.
Two squads for each car to be unloaded and the necessary mechanics are marched to the unloading place. Four selected noncommissioned officers and a mechanic are detailed for each place or chute where a car is to be unloaded. These men remain at the same chute or platform until all of the cars there have been emptied. The two squads for each car is sufficient to provide one man for each two animals to be unloaded.
Men are held in ranks until needed.
An officer should be in charge of nnloadinc: each car. • 520. Two of the selected noncommissioned ofhcors of tlie special detail- are assigned to Avork inside the car, th(^ remaining; two working outside the car at the door. The mechanic removes the fastenings and assists in opening the door.
The principal dithculty in unloading is to prevent the animals from leaving the car before the gangway, gates, etc., are in place and to avoid overcrowding in the doorway.
521. As soon as the car is in place the door is opened enough to permit the noncommissioned officers who work inside to enter. These men at once enter, leaving the breast bar in place, and quiet the animals nearest the door by speaking to and caressing them.
Everything being in readiness, the door is completely opened and the gangway, gates, etc., put in position as quickly as possible. If a loading pen is avaihible, the men assigned to the car go into the pen to catch the animals up after they enter it. If no pen is available, the men line themselves up on either side of the door, each one taking an animal in turn as he leaves the doorway. All men being in their places, the noncommissioned officers inside the car remove the breast bar. All four of the selected noncommissioned officers endeavor to make the animals leave the car quietly and in single file.
522. As soon as Ihe animals of the first lot have been caught up pairs are formed in column and led around at a slow walk. A noncommissioned officer should be designated to lead the column of this first lot. As each succeeding car is unloaded and the animals caught up the extra men join the rear of the column.
523. If ample feeding lots are available a separate lot should be assigned each separate car. Effort is made to keep together the animals that have been in the same car and to reload them together. Men remain Mith the pairs when they catch up and do not attempt to find their own animals, unless the latter are with the same carload to which the driver is assigned. In this case a driver may be alluvred to take his own animals .after they are tied up for grooming and feeding.
legs induced by the long standing in the cars. For this retison the exercise should be continued for 10 or 15 minutes after the unloading of tlio last car has been completed.
525. Hay having been distributed and the exercising completed, the animals are properly secured and then groomed while they are eating hay. During the grooming particular attention is paid to cleaning and hand rubbing the legs thoroughly. All kicks, cuts, and abrasions are reported to the stable sergeant, who visits all the animals at this time.
526. During the grooming a special detail proceeds to the stock ca.rs and renew the sanding, if material therefor is available. Tools for this purpose may frequently be had from the railroad or stockyard authorities, or they may be taken from the carts. Sometimes it may be necessary to detail a certain number of men to draw water for the animals,
527. The grooming is continued until the animals must be watered, which should be in time to allov/ them to eat their oats before it is necessary to begin reloading.
At the proper time the officer in charge of feeding causes the filled feed bags to be taken and distributed after all the animals liave been watered. He then details a squad to collect the feed bags and turn them over to the stable sergeant at the forage car after they have been removed from the animals.
528. At least tvro hours should be allowed for the unloading, feeding, and reloading. In all loading and unloading, particular care must be exercised to avoid any shouting or excitement on the part of the men. These are the principal causes of excitement on the part of horses or mules, which, in turn, is the source of most difficulties in handling the animals.
529. Upon arrival at the detraining station complete and early Information as to the facilities for unloading and other conditions is essential to the orderly planning and conduct of the detraining. E^or this purpose each train should be met as it arrives by an officer or officers from preceding organizations.
530. The detraining should -ordinarily be so conducted as to release the cars as rapidly as possible and thus avoid congestion in the detraining station. Following this principlej the men take all of their equipment with them upon leaving the coaches ; the stock cars are unloaded first, the flat cars next, and finally the baggage cars and the box cars.
531. Upon firrival the noncommissioned officers cause the men to take their equiiDment. but no one leaves the cars except the officers and the first sergeant until ordered to do so. The necessary plan for unloading having been made, the men are ordered to leave the cars and fall in at a designated place. Rolls having been called, the mess sergeant and the cooks proceed directly to the baggage car containing the kitchen equipment and the rations. The remainder of the company is marched to a suitable place where the men may leave their equipment. The men having deposited their equipment, a gtiard is placed, the necessary details are made, and the work of unloading begun.
532. ^Vhenever practicable, arrangements are made at once for unloading the kitchen equipment and necessary rations for the first meal and for transporting them to a suitable place. Such men as are necessary are detailed to assist the mess sergeant and cooks in this work. The animals are unloaded as heretofore described, but are arranged by .squads and sections as they are unloaded and are secured at once, care being exercised that they are not tied to movable or flimsy structures. The feed bags are not filled, but hay is fed at once. Two or more men are set to vrork to sort the feed bags out by sections, and later, when the animals are being harnessed, to turn them over to the section leader.
During the imloading of the horses the qtiartermaster sergeant, the mechanics not assisting at the stock cars, and one gun squad proceed to the ilat cars and begin the removal of the chocks preparatory to unloading. As the timbers are removed they are taken to a suitable place, and one man is left with them as guard until they are finally disposed of.
533. The animals having been unloaded, secured, and given a feed of hay. work on unloading the carts and wagons is begun. Usually a part of the men may be usefully employed in unloading the baggage and box cars at the same time.
534. As the carts and wagons are unloaded they are run to a suitable place and arranged in proper order in park or column convenient for hitching in. A guard is posted over the park as soon as the vehicle is placed.
535. Ordinarily the company should harness, hitch, and clear the vicinity of the station as soon as the animals, vehicles, and harness have been unloaded. When the box cars have not been
536. While the foregoing methods of loading and unloading outline the principles \yhich should be foliov.'ed, the details of the plan adopted must be varied to conform to the conditions of eacli particular place.
transport service.
The necessary preliminaries before embarking, routine details on board Army transports, and methods of disembarking are prescribed in the Army Transport Service Regulations, a copy of which will be secured by the commander of each organization designated for oversea service.
538. For oversea transportation all carts and wagons should be knocked down. Harness and horse equipments, except such as are needed for use during the trip, will be boxed and marked to show the section to which they belong.
The men retain in their possession their personal equipments.
^Ul carts and wagons should be fully equipped before embarking and should be stored where they will be accessible. For expeditions into the theater of operations it is obligatory that all of the personnel, materiel, and ammunition of a company be carried on the same vessel.
539. Animals are led aboard if docking facilities permit, otlier\\ise tliey are lightered to the transport and hoisted aboard, if necessary, by means of slings or other appliances, with which the transport should be provided.
In calm water the animals may be lowered into the water or driven overboard from low ports and required to s\^im ashore. In such case the first overboard may be led from small boats.
camps and temporary camps.
542. Semipermanent camps are used for troops in mobilization, concentration, or maneuver camps, and during such pauses in operations as permit the better care of troops.
days at most.
544. In large commands the halt order should assign camp sites to the next smaller commands, and the commanders of the latter should locate their respective commands to the best advantage on the area assigned them.
545. Even in small commands, the commanding officer, or an officer designated, should precede the column to look over the camping ground and decide on the arrangement of the camp, so that on arrival the command may immediately occupy the ground assigned it. and comn^anders may be promptly informed as to arrangements for water, fuel, forage, and rations.
546. If the area of the available ground is sufficient and suitalile, the camp of the company or battalion should conform to Plate IX and the Plates A and B, published in the Field Service Regulations. When the camp site has a restricted, area, intervals and distances are reduced.
Under service conditions, camp sites that will permit the encampment in regular order, as indicated in the plates, will not often be available and regularity must be sacrificed.
on substantial posts, and corrals when practicable. The equipment therefor is classed as equipment " B," and is not carried on division trains, but when required is brought up by other' transportation.
549. Lack of sufficient rest renders troops unfit for hard work and diminishes their power of resisting disease. Therefore commanders should secure for the troops, whenever possible, their accustomed rest. Every effort must be made to provide adequate shelter for both men and animals.
550. Men should not be on damp ground. In temporary camps and in bivouac they raise their beds, if suitable material, such as straw, leaves, or boughs, can be obtained, or use their ponchos or slickers. In cold weather and when fuel is plentiful the ground may be warmed by lires, the men making their beds after raking away the ashes.
as possible.
552. Suitable tents or other shelter must be provided for workshops for mechanics and for kitchens. Condemned canvas can be utilized for these purposes in camps of a duration too short to justify suitable buildings.
cold winds, rain, or snow in winter lose condition very rapidly.
553. The detailed arrangements of the normal semipermanent camps are given in Plate IX. Whenever practicable the width of the camps therein shown should be somevvdiat extended.
Tlie picket line should be well drained by cutting ditches about 12 feet on either side of the line and throwing the earth to the center. Whenever practicable the ground should be covered with broken stone, sand, or cinders. Particular care must be taken to provide dry footing not only on the picket line but around the watering places in semipermanent camps.
hot weather are provided for the animals, if practicable.
555. To prevent stampeding in camp it will in most cases be sufficient for the men to go quietly among the animals at the first sign of fright and speak to them. If horses are stampeded, men should mount the fastest animals within reach, place themselves in front of the herd, and conduct it back to camp. V/ith old horses the sounding of stable call may prevent or stop a stampede.
556. One of the greatest difficulties with animal transportation in campaign is to secure sufficient long forage. On this account the greatest attention should be given to grazing at every opportunity.
The animals are either held on the halter rope, picketed on the lariat, turned loose in inclosed pastures, or if there has been opportunity for sufficient training they may be herded.
Special effort should be made to give them an hour or two of grazing in the morning while the dew is on tlie grass (not clover), especially if the supply of hay at night has been short, and in such cases they should not be disturbed until the last moment, time lost being made up by more rapid marching.
Should protection from an enemy be necessary the animals are taken out to graze under charge of an officer as soon as possible after camping. They are taken as far as is safe, in order to keep the nearer grass for night. It is occasionally practicable to arrange the camp so as to use the wagons and natural obstacles to inclose a space for night grazing.
THE SELECTION OF CAMP SITES IN THE FIELD.
557. In campaign, tactical necessity may leave a little choice in the selection of camp sites, but under any conditions the requirements of sanitation should be given every consideration consistent with the tactical situation.
water.
Good roads should lead to the camp. Interior communication throughout the camp should be easy. A camp near a main road is undesirable on account of dust and noise.
through the camp of another.
The site should be sufficiently high and rolling to drain off storm water readily, and, if the season be hot, to face the breeze. In cold weather it should preferably have a southern exposure, with woods to break the prevailing winds. In warm weather an eastern exposure, with the site moderately shaded by trees, is desirable.
The site should be dry. For this reason porous soil, covered with stout turf and underlaid by a sandy or gravelly subsoil, is best. A site on clay soil, or where the ground water approaches the surface, is damp and unhealthful.
Alluvial soils, marshy ground, and ground near the base of hills or near thick v/oods or dense vegetation are undesirable as camp sites on account of dampness. Ravines and depressions are likely to be unduly warm and to have insufficient or imdesirable air currents.
Proximity to marshes or stagnant w^ater is undesirable on account of the dampness and mosquitoes and the diseases which the latter transmit. The high banks of lakes or large streams often make desirable camp sites.
sudden freshet.
The occupation of old camp sites is dangerous, since these are often permeated by elements of disease vrhich persist for considerable periods. Camp sites nmst be changed promptly when there is evidence of soil pollution, or when epidemic disease threatens, but the need for frequent changes on this account may be a reflection on the sanitary administration of the camp.
washing clothing.
If the stream be small, the water supply may be increased by building a dam. Small springs may be dug out and each lined with a gabion, or a barrel or box, with both ends removed, or with stones, the space between the lining and the earth being filled with puddled clay. A rim of clay should be built to keep out surface drainage. The same method may be used near swamps, streams, or lakes to increase or clarify the water supply.
560. Water that is not known to be pure should be boiled 20 minutes ; it should then be cooled and aerated by being poured repeatedly from one clean container to another, or it may be purified by approved apparatus supplied for the purpose.
561. Arrangements should be made for men to draw water from the authorized receptacles by means of a faucet. The dipping of water from the receptacles ar the use of a common drinking cup sJionld he proJiibited.
562. On the march, including camps, the daily requirements of water may be estimated at 6 gallons per man or 10 gallons per horse, in permanent or' semipermanent camps the supply should be sufficient to provide from 25 to 30 gallons per man and 15 gallons per hor>?e per day.
the same character.
A narrow trench for the fire, about 1 foot deep, under the pole, protects the fire from the wind and saves fuel. A still greater economy of fuel can be effected by digging a similar trench in the direction of the wind and slightly narrower than the diameter of the kettles. The kettles are then placed on the trench and the space over ^t and between the kettles filled in with stones, clay, etc.. leaving the flue rtmning beneath the kettles. The draft can be improved by building a chimney of stones, clay, etc., at the leeward end of the flue.
drainage and improves the draft.
564. The lack of portable ovens can be met by ovens constructed of s^one and covered witlf earth to retain the heat. If no stone is. available, an empty barrel with one head out is laid on its side and covered with vv-et clay to a depth of 6 or more inches, and then with a layer of dry earth equally thick. A flue is constructed with clay above the closed end of the barrel, which is then burned out with a hot Are. This leaves a baked clay covering for the oven.
A recess can be similarly constructed with boards or even brushwood, supported on a horizontal pole resting on upright posts, covered and burnt out as in the case of the barrel.
and ends.
565. Food must be protected from flies, dust, and sun. Facilities must be provided for cleaning and scalding the mess equipment of the men. Kitchens and the ground around them must be kept scrupulously clean.
kitchen fire or in an improvised crematory.
567. In temporary camps, if the soil is porous, liquid refuse from the kitchens may be strained through sacking into seepage pits dug near the kitchen. Boards or poles covered with brush or grass and a layer of earth may be used to prevent the access of flies. The strainer should also be protected from flies. Pits of this kind in clay soil will not operate successfully. All pits should be filled with earth when the camp is abandoned.
DISPOSAL OF EXCKETA.
568. Immediately on arriving in camp sinks should be dug. This is a matter of fundamental sanitary importance, since the most serious epidemics of camp diseases are spread from human excreta.
One sink is usually provided for eacli company, and one for the officers of each battalion. Those for the men are invariably located on the side of camp opposite the Ivitchens. All sinlis should be so placed that they can not pollute the water supply or camp site as a result of drainage or overflow. To insure this, their localities and their distance from camp may be varied.
straddle, will suffice.
In camps of longer duration, and when it is not possible to provide latrine boxes, as for permanent camps, deeper trenches should be dug. These may be used as straddle trendies or a seat and back rest provided from poles or other available material. They should be screened by brush, condemned canvas, or other material. "When open trenches are used, special care must be taken to insure that all excreta is covered with earth, lime, or ashes as soon as it is deposited.
570. In permanent or semipermanent camps special sanitary facilities for the disposal or disinfection of excreta will ordinarily be provided. When trenches r.re used in such camps they should be at least G feet deep and 12 feet long and not more than 2 feet wide. Seats are walled to the ground and provided v/ith lids to keep flies from reaching the deposits; urinal troughs discharging into the trenches are provided. Each day the latrine boxes are thoroughly cleaned, outside by scrubbing, and inside by applying when necessary a coat of crude oil or whitewash. The pit is burned out daily with approximately 1 gallon of crude oil and 15 pounds of straw. When filled to within 2 feet of the surface, such latrines are discarded, filled with earth, and their position marked.
In permanent camps urine tubs should be placed in the company streets at nightfall ; they are emptied after reveille. Their location should be plainly marked and thoroughly and frequently disinfected.
571. In camps of some duration guard and other duties follow closely the custom in garrison. Machine-gun organizations provide guards for their parks, picket lines, and for such
other places within their camps as may be necessary. These are known as interior guards and it should ordinarily be sufficient to furnish for each picket line a double sentinel from the or.canization to which the line pertains.
The guard is, when practicable, mounted by battalion or regiment, the necessary officers and noncommissioned officers being detailed by roster. The necessary sentinels for stores, etc., are also detailed by battalions or regimental roster; especially in permanent or semipermanent camps all members of guards are sent to join their organizations at reveille.
V.'hen prisoners are to be guarded during the march, they are either turned over to the organization commander or marched v\-ith and guarded by the company to vv'hich the officer of the day belongs. The protection of the camp in campaign is provided for by means of outposts (305).
The camp is policed daily after breakfast and all refuse burned. Tent \yalls are raised immediately after breakfast and the bedding and clothing aired daily, v.^eather permitting.
572. When troops bivouac for the night the necessity for extensive sanitary precautions is not great ; however, shallow sink trenches are dug to prevent general pollution of the vicinity. If the cooking be collective, shallow kitchen sinks should be dug. If the cooking be individual, the men should be required to build their fires- on the leeAvard Hank of the camp ov bivouac.
arranged for ceremonies is prescribed by Army Regulations.
When forming for ceremonies the companies of the battalion and the battalions of the regiment are posted from right to left in line and from head to rear in column, in the order of rank of their respective commanders present in the formation, the senior on the right or at the head.
face to the front.
574. At the command present arms, given by the colonel, the lieutenant colonel, and the colonel's staff salute; the major's staff salute at the major's command. Each staff returns to the carry or order when the command order anus is given by its chief.
on tiieir own parades and informally inspected.
At adjutants eall, except for ceremonies involving a single battalion, each battalion is formed on its own parade, reports are received, and the battalion presented to the major. At the second sounding of adjuianfs eall the regiment is formed.
GENERAL RULES.
576. The adjutant posts men or otherwise marks the points where the column changes direction -in such manner that its Hank in passing will be about 12 paces from the reviewing officer.
of the line, is indicated by a marker.
Officers of the same or higher grade, and distinguished personages invited to accompany the reviewing officer, place themselves on his left ; their staifs and orderlies place themselves, respectively, on the left of the staff and orderlies of the reviewing officer ; ail others who accompany the revievring officer place themselves on the left of his staff, their orderlies in rear. A staff officer is designated to escort distinguished personages and to indicate to them their proper positions.
577. While riding around the troops, the reviewing officer may direct his staff", flag, and orderlies to remain at the post of the reviewing officer, or that only his personal staff and flag shall accompany him ; in either case the commanding officer alone accompanies the reviewing officer. If the reviewing officer is accompanied by his entire staff, the staff officers of the commander place themselves on the right of the staff of the reviewing officer.
The reviewing: officer and others at the reviewing? stand salute the color as it passes ; when passing around the troops the reviewing officer and those accompanying him salute the color when passing in front of it.
mander.
579. After saluting the reviewing officer, the commanding officer of the troops turns out of the column, takes post on the right of the reviewing offi.cer, and returns saber; the menibers of his staff accompanying him take post on the right of the reviewing oHicer's staff and return saber. When the rear element of his command has ]oassed, without changing his position, the commanding officer of the troops salutes the reviev.ing officer; he and the members of his staff accompanying him then draw saber and rejoin his command. The commanding officer of the troops and the members of his staff are the only ones who turn out of the column. •
580. If the person reviewing the command is not mounted, the commanding officer and his staff, on turning out of the column «fter passing the reviewing officer, dismount preparatory to taking post. In such case the salute of the commanding officer, prior to rejoining his command, is made with the hand before remounting.
581. WJien the rank of the reviewing officer entitles him to the honor, each regimental or battalion color salutes at the command present arms, given or repeated by the major of the battalion with which it is posted ; and again in passing in review.
officer is passing in front of and in rear of the organization.
Each band, immediately after passing the reviewing offiicer, turns out of the column, takes post in front of and facing him, continues to play until its regiment has passed, then ceases playing and follov.'s in rear of its regiment ; the band of the following regiment commences to play as soon as the preceding band has ceased.
flourishes, or ruffles are sounded by all the field music.
584. The formation for review may be modified to suit the ground, and the present onus and the ride around the line by the reviewing officer may be dispensed with.
585. If the post of the reviewing officer is on the left of the column, the troops march in review with the guide left ; the commanding officer and his staff turn out of the column to the left, taking post as prescribed above, but to the left of tlie reviewing officer ; in saluting, the captains give the command : 1. Eiics, 2. Left.
pass in review in quick time only.
587. In reviews of brigades or larger commands, each battalion, after the rear has passed the reviewing officer 50 paces, takes the double time for 100 yards in order not to interfere with the march of the column in rej^r ; if necessary, it then turns out of the column and returns to camp by the most practicable route ; the leading battalion of each regiment is folloAved by the other units of the regiment.
588. In a brigade or larger review a regimental commander may cause his regiment to stand at ease, rest, or staek arms and fall out and resume attention, so as not to interfere with the ceremony.
589. When an organization is to be reviewed before an inspector junior in rank to the commanding officer, the commanding officer receives the review and is accompanied by the inspector, who takes post on his left.
590. The bati alien having been formed in line or in line of sections : (If the battalion is formed in line of sections, the front of the battalion may be reduced by causing the section to close to 10-pace intervals. The command will be: 1. On right section, to 10 paees, 2. Close. Ten paces being the interval between squads in line.) The major faces to the front; the reviewing
The reviewing ofRcer approaches to about six paces from the major, the latter salutes, takes post on his right, and accompanies him around the battalion. The band plays. The reviewing officer proceeds to the right of the band, passes in front of the captains to the left of the line, and returns to the right, passing in rear of the file closers and the band.
On arriving again at the right of the line, the major salutes, halts, and when the reviewing officer and staff have passed moves directly to his post in front of the battalion, faces it, and commands: 1. Pass in revieii', 2. Platoons {squads) right {left) turn, 3. March. 4. Forward, 5. Maech.
and halts.
At the last command, given when the band has changed direction, the battalion moves off, the band playing; without command from the major, the column changes direction at the points indicated ; the major takes his post 30 paces in front of the band immediately after the second change ; the band having passed the reviewing officer, turns to the left out of the column, takes post in front of and facing the reviewing officer, and remains there until the review terminates.
The major and staff salute, turn the head as in eyes right. and look toward the reviev,-ing officer when the major is 6 paces from him ; they return to the carry and turn the head and eyes to the front when the major has passed 6 paces beyond him.
AVithout facing about, each captain or'special unit commander, except the drum major, commands : 1. Eyes, in time to add, 2. Right, when at 6 paces from the reviewing officer, and commands Feont when at 6 paces beyond him. At the command Eyes the company officers armed with the saber execute the first motion of present saber ; at the command Right all turn head and eyes to the right, except drivers, the company officers complete present saher, and the noncommissioned officers armed
with the saber execute the first motion of present saber; at the command Feoxt all turn head and eyes to the front, and officers and noncommissioned officers armed with the saher resume the carry saber ; without arms in hand, the first motion of the hand salute is made at the command Right, and the second motion not made until the command Feo^tt.
Noncommissioned staff officers, noncommissioned officers in command of subdivisions, and the drum major salute, turn the head and eyes, return to the front, resume the carry or drop the hand at the points prescribed for the major. Olucers and dismounted noncommissioned officers in command of subdivisions with arms in hand render the saber salute. Drivers charged with the gait, trace, and direction do not execute eyes right.
If the reviewing officer is entitled to a salute from the color the regimental color salutes when at 6 paces from him, and is raised when at G paces beyond him.
The major, having saluted, takes post on the right of the reviewing officer, returns saber and remains there until the rear of the battalion has passed, then salutes, draws saber, and rejoins his battalion. The band ceases to play when the column has completed its second change of direction after passing the reviewing officer.
of sections.
At the colonel's command, Pass ix Review, the captain gives the necessary command for forming his company in column of squads, moves off in time to follow the organization, preceding it at proper distance.
592. If dismounted, the officer receiving the parade, and his staff, stand at parade rest, with arms folded, while the band is sounding off; they resume attention with the adjutant. If mounted, they remain at attention.
A (or other) company, present or accounted for; or, A (or other) company (so manjO, officers, or enlisted men absent; and resume the order saber. At the same command given by the re;?imental adjutant, the majors similarly report their battalions.
594. At adjutanVs call the battalion is formed in line or in line of sections, but not presented. The major takes post at a convenient distance in front of the center and facing the battilion.
Tie adjutant, from his post in front of the center of the battalioi, commands : 1. Parade, 2. Rest ; the battalion executes parale rest. The adjutant directs the band : Sound Off.
Th* band, playing in quick time, passes in front of the line of officer to the left of the line and back to its post on the right, when it ceases playing. At evening parade when the band ceases playing, retreat is sounded by the field music and, following, the last note and while the flag is being lowered, the band tays the Star-Spangled Bannee.
Just before the last note of retreat the adjutant comes to attentiai and, as the last note ends, commands : 1. Battalion, 2. Attrition. When the band ceases playing he turns about and reprts : Sir, the parade is formed. The major directs the adjutan: Receive the reports, sir.
The rports received, the adjutant turns about and reports: Sir, all o'c present or accounted for; or. Sir, (so many) officers or enlistd men are absent, including in the list of absentees those froi the band and field music reported to him by the drum major pnr to the parade.
band playing; the captain of the center or right center company is the guide and marches on the major ; the officers are halted at 6 paces from the major by the senior, who commands : 1. Officers, 2. Halt. They halt and salute, returning to tiie carry saber ^Yith the major. The major then gives such :nstructions as he deems necessary, and commands : 1. Officers, post, 2. March.
when the last company has passed, the ceremony is conclided.
The band continues to play while the companies are in narch upon the parade ground. Companies are marched to their respective parades by their captains.
When the company officers have saluted the major, hi may direct them to form lino with the .staff, in which case t^ey individually move to the front, passing to the right and left of the major and staff, halt on the line established by tb staff, face about, and stand at attention. The music cease when the officers join the staff. The major causes the compiuies to pass in reviev/ under the command of their first sergants by the same command as before. The company officer return saber v.ith the major and remain at attention.
595. The regiment is formed in line or in line of msses ; the formation having proceeded up to, but not including the Present, the parade proceeds as described for the battUon, with the following exceptions :
The second major is the guide and marches on the colonel.
After being dismissed by the colonel, each major moves individually to the front, turns outvcard, and followed by his staff resumes his post by the most direct line. The colonel directs the lieutenant colonel to march the regiment in review; the latter moves to a point midway between the colonel and the regiment and marches the regiment in review as prescribed. If the lieutenant colonel is not present, the colonel gives the necessary commands for marching the regiment in review.
The captain returns saber, inspects the lieutenants, the ranks,
and the tile closers, beginning on the right of each and returning by tlie left and rear. Each man as approached executes Inspcctio'i. Pistol, and after being passed by the inspector executes R(\t'uni, Pistol. The buglers raise their bugles for inspection. During the inspection of the ranks the lieutenants face abou\ and stand at ease; they may be directed to accompany the eiptain or to assist in the inspection. Upon the completion of ;he inspection the lieutenants face to the front and resume the attention. The captain causes the company to close ranks (129).
598. Shoitd the inspector be other than the captain, the lattei', after conmanding Front, adds Rest, and faces to the front (when the irspector approaches, the captain faces to the left) brings the company to attention, faces to the front, and salutes. The salute aclnowledged, the captain carries saber, faces to the left, command?: Prepare for Inspection, and again faces to the front.
them as he may designate; the men, without accoiiterments, stand uncovered near their respective bunks ; in camp they stand covered without accouterments. in front of their tents'; upon the approach of tlie inspector the first sergeant commands : Attention, salutes, and leads the way through the quarters or camp.
MOUNTED INSPECTIONS.
601. Inspections will habitually be mounted. Machire-gun organizations carry, for inspection mounted, every article that is prescribed as a part of the regular equipment and for which there is a specially designated place on the transportation, ^he signalmen and scouts are assigned, three to each gun sqtad.
602. The company being in line or in close line, the captain commands: 1. In -front of the carts, 2, Fall In. The .gun squads fall in in front of the carts, as described in paragraph 162. The captain then causes the company to open ranks, as described in paragraph 128, and aligns the company oi the right equad.
the buglers. All mounted men dismount and stand lo horse.
The captain then takes post 5 paces to the front of the right of the company. If the inspection is to be conducted by him. he faces to the left and commands : Prepaee fop. Inspection. He then passes down in front of the platoon leade'S, inspecting them, and returns to the right of the company ii front of the section leaders, inspecting them.
The inspection of the dismounted men is car'ied on by the company commander, assisted by the platoon haders, if he so desires, as in the company dismounted.
equipment, he gives the command : Izvtspection Equipment.
At this command the gun squads secure the guns, tripods, etc.. and mount tliem as described in paragraph 147 10 paces in front of their respective positions. The ammunition boxes, tool boxes, water boxes, etc., are placed in line as described in paragraph 147. The men take position as described in paragraph 147 and remain at attention during the inspection. The carts, signalmen, and agents do not move.
For this inspection the captain may direct each platoon leader to inspect the equipment of his platoon. This inspection of equipment should cover the following points :
(1) Roller handle should be straight — when the roller handle is on the dead stop the tail of the roller handle should not touch tlie roller. (?) Recoil spring and fusee.
cartridges are even vrith the ends of the brass strips. Turn a few cartridges around in the belt to see if they fit very tightly.
603. The company having been .inspected, the captain commands : Replace EquiPxMent. At this command the equipment is returned to its original position, and the men fall in in front of the carts.
604. While inspecting the company or accompanying the inspector the captain does not return his saber while mounted; if dismounted, he returns saber.
605. Should the inspector be other than the captain, the latter prepares the company for inspection and awaits the arrival of the in&ijector. Upon the approach of the inspector the captain, at his post, salutes. The inspector returns the salute and informs him of the character of the inspection desired ; the captain gives the necessary commands, faces to the front, and, when inspected, accompanies the inspector.
607. The battalion staff officers place themselves in line with 1-pace intervals about 20 paces in front of the coUiran, opposite the center, in order of rank from right to left ; the noncommissioned staff form in a similar manner 3 paces in rear of the staff officers ; the guard of the standard marches to the front and takes post 5 paces in rear of the center of the line of the noncommissioned staff. The major takes post in front of the center of the column 3 paces in front of the staff.
return, saber when inspected.
610. The inspector, commencing at the head of the column, inspects the noncommissioned staff and guard of the standard. The noncomimissioned staff and guard of the standard may be dismissed as soon as inspected.
611. The captain of each company not undergoing inspection brings the men to rest. As the inspector approaches the company the captain brings it to attention : as soon as he himself has been inspected he gives the necessary com,mands. returns saber, and accompanies the inspector. The inspector proceeds as in company inspection. At its completion the captain causes the company to cZo.se ranks and brings the company to rest. Upon intimation from the inspector, the major may direct that each company in turn be dismissed as soon as inspected.
612. The battalion may be inspected in line. The inspection is conducted according to the same principles as when formed in column. The major and his staff are inspected at their posts in front of the center of the line; the band, which remains at its post on the right, is next inspected ; then the companies in order from right to left.
On the approach of the inspector, if he be other than the company commander, the organization is brought to attention and aligned by the company commander.
ticable, by a review.
The adjutant is provided with the muster roll of the field, stair, and band, the surgeon with the hospital roll ; each captain with the roll of his company. A list of absentees, alphabetically arranged, showing cause and place of absence, accompanies each roll.
After muster, the mustering officer, accompanied by the company coumianders and such other officers as he may designate, verifies the presence of the men reported in hospital, on guard, etc.
619. The President of the United States will be received with regimental standards or colors, officers and troops saluting, the drums giving four ruffles and the bugles sounding four flourishes. The ruffles and flourishes will be followed by the na-
An ex-President and the Vice President of tlie United States will be received with the same honors as prescribed for the President, except that the flourishes will be followed by a march in lieu of the national anthem.
The President of a foreign Republic, a foreign sovereign, or a member of a royal family will be received with the same honors as the President of tlie United States, except that the national anthem of their country will be played.
Officers of the following grades of rank will be received with regimental standards or colors, officers and troops saluting, and field music playing, as follows: General, four ruffles and flourishes ; lieutenant general, three ruflles and flourishes ; major general, two ruffles and flourishes; brigadier general, one ruffle and flourish.
flourishes.
620. To the members of the Cabinet, the Chief Justice, the President pro tempore of the Senate, the Speaker of the House of Representatives, American or foreign ambassadors, and governors within their respective States and Territories, the same honors are paid as to the general, except that a foreign ambassador will be received vrith the national anthem of his country and that the number of guns fired as personal salute will be as prescribed in Army Regulations ; to the Assistant Secretary of AYar and to American or foreign envoys or ministers the same honors as to the lieutenant general ; to officers of the Navy the honors due to their relative rank ; to officers of marines and volunteers, and militia, when in the service of the United States, the honors due to like grades in the Regular service ; to officers of a foreign service the honors due to their rank.
In rendering personal honors, vsdien the command " Present arms " is given, officers and men in uniform who are not in formation and are in view and within saluting distance shall salute and shall remain in the position of salute until the end of ruffles and flourishes, or, if none, until " Order arms."
music sounding " To the Color " or " To the Standard." Officers or enlisted men passing tlie uncased color will render the prescribed salute; with no arms in hand, the salute will be the hand salute, using the right hand, the lieaddress not to be removed.
622. Whenever the national anthem is played at any place when persons belonging to the military service are present, all officers and enlisted men not in formation shall stand at attention, facing toward the music (except at retreat, when they &hall face toward the flag). If in uniform, covered, they shall salute at the first note of the anthem, retaining the position of salute until the last note of the anthem. If not in uniform and covered, they shall uncover at the first note of the anthem, holding the headdress opposite the left shoulder, and so remain until its close, except that in inclement weather the headdress may be held slightly raised.
When played by an Army band the national anthem shall be played through without repetition of any part not required played upon official occasions.
The same marks of respect prescribed for observance during the playing of the national anthem of the United States shall be shown toward the national anthem of any other country when played upon official occasions.
623. No honors are paid by troops when on the march or in the field, except that they may be called to attention, and no salute is rendered when marching in double time or at the trot or gallop.
624. The commanding officer is saluted by all commissioned officers in command of troops or detachments. Troops under arms will salute as prescribed in drill regulations.
625. Wlien making or receiving official reports or on meeting out of doors all officers will salute. Military courtesy requires the junior to salute first, but when the salute is introductory to a report made at a military ceremony or formation to the representative of a common superior — as, for example, to the adjutant, officer of the day, etc. — the officer making the report, whatever his rank, will salute first ; the ofiicer to whom
received and understood the report.
626. Salutes shall be exchanged between officers and enlisted men not in military formation, nor at drill, work, games, or mess, on every occasion of their meeting, passing near, or being addressed, the officer junior in rank or the enlisted man saluting first.
When an officer enters a room where there are several enlisted men the word " attention " is .given by some one who perceives him. when all rise, uncover, and remain standing at attention until the officer leaves the room or directs otherwise. Enlisted men at meals stop eating and remain seated at attention.
An enlisted man, if seated, rises on the approach of an officer, faces toward him, stands at attention, and salutes. Standing, he faces an officer for the same purpose. If the parties remaiji in the same place or on the same gi'ound, such compliments need not be repeated. Soldiers actually at work do not cease work to salute an officer unless addressed by him.
Before addressing an officer, an enlisted man makes the prescribed salute with the weapon with which he is armed, or, if unarmed, with the right hand. He also makes the same salute after receiving a reply.
627. In uniform, covered or uncovered, but not in formation, officers and enlisted men salute military persons as follows: ■\Vith arms in hand, the salute prescribed for that arm (sentinels on interior guard duty excepted) ; without arms, the righthand salute.
Officers and enlisted men will render the prescribed salutes in a military manner, the officer junior in rank or the enlisted man saluting first. When several officers in company are saluted, ail entitled to the salute shall return it.
Except in the field, under campaign or simulated campaign conditions, a mounted officer (or soldier) dismounts before addressing a superior officer not mounted.
post of the commander.
In public conveyances, such as railway trains and street cars, and in public places, such as theaters, honors and personal salutes may be omitted when palpably inappropriate or apt to disturb or annoy civilians present.
629. Officers and enlisted men passing the uncased color will render honors as follows: If in uniform, they will salute as required in paragraph 628 ; if in civilian dress and covered, they will uncover, holding the headdress opposite the left shoulder v.ith the right hand ; if uncovered, they will salute with the right-hand salute.
Sentinels on post doing interior guard duty conform to the foregoing principles, but salute by presenting arms wiien armed with the rifle. They vvill not salute if it interferes with the proper performance of their duties. Troops under arms will salute as prescribed in drill regulations.
630. Commanders of detachments or other commands will salute officers of grades higher than the person commanding the unit by first bringing the unit to attention and then saluting as required.
ers will exchange salutes, both commands being at attention.
632. Salutes and honors, as a rule, are not paid by troops actually engaged in drill, on the march, or in the field under campaign or simulated campaign conditions. Troops on the service of security pay no compliments whatever.
633. If the command is in line at a halt (not in the field) and armed with the rifle, or with sabers drav/n, it shall be brought to " present arms " or " present sabers " before its commander salutes in the following cases : When the national anthem is played, or when " To the Color " or " To the Standard " is sounded during ceremonies, or when a person is saluted who is its immediate or higher commander or a general officer, or when the national or regimental color is saluted.
the position of salute vrhile the national anthem is being played ; also at retreat and during ceremonies when " To the Color " is played if no band is present. If not under arms, the orj^anizations shall be brought to attention at the hrst note of the national anthem, " To the Color," or " To the Standard," and the saltite rendered by the officer or noncommLssioned officer in command, as prescribed in regulations, as amended herein.
Marine Corps.
637. Soldiers at all times and in all situations pay the same compliments to officers of the Army, Navy, Marine Corps, and Volunteers, and to officers' of the National Guard in uniform as to officers of their own regiment, corps, or arm of service.
warning calls.
638. Fii'st call, guard mounting, full dress, overcoats, drill, stable, water, and boots and saddles precede the assembly by sucli intervals as may be prescribed by the commanding officer.
Adjutant's caU.—The signal for the companies or guard details to assemble on the camp or garrison parade ground; it follows the assembly at sucli interval as may be prescribed by the commanding officer. It is also used as a signal for the battalions to form regiment, following the first adjutant's call at such interval as the commanding officer may direct.
Army Regulations.
Assembly, reveille, retreat, adjutant's call, to the color, the flourishes, and the marches are sounded by all the musicians united; the other calls, as a rule, are sounded by the musician of the guard or orderly musician ; he may also sound the assembly when the musicians are not united.
The drill signals are taught in succession, a few at a time, until the officers and men are thoroughly familiar with them, some drills being specially devoted to this purpose.
The memorizing of tliese signals will be facilitated by observing that signals for all moveuieuts to the right are on the ascending scale; that signals for the correspoudinc.- movement to the left are corresponding signals on the descending scale; that the changes of gait are all upon the same note.
NOMENCLATURE AND CAEE.
644. The soldier is first taught the nomenclature of the parts of the pistol necessary to an understanding of its action and use the proper measures for its care and preservation, as given in Ordnance Pamphlet descriptive of the pistol.
645. Whenever men fall in ranks with the automatic pistol the officer or noncommissioned officer in charge will command : 1. Raise, 2. Pistol, 3. Withdraw, 4, Magazine, 5. Open, 6. Chamber, 7. Close, 8. Chamber, 9. Insert, 10. Magazine, 11. Return, 12. Pistol.
in a safe condtion.
646. The pistol with cartridge in chamber is habitually carried cocked and locked, whether in the hand or in the holster. The hammer will not be lowered while a cartridge is in the chamber.
647. In campaign, the pistol should habitually be carried with a magazine in the socket, loaded with seven ball cartridges, chamber empty, hammer down. The extra magazines should also be loaded with seven ball cartridges each.
648. When action seems imminent, the pistol should be loaded by command. It may then be returned by command to the holster till the time for its use arrives.
649. Recruits are first taught the motions of loading and firing without using cartridges. However, the automatic action and the effect of ball cartridges in operating the slide can not be taught without firing ball cartridges. Practice without cartridges is very necessary to acquire facility in the exact movements of the manual, and in aiming, holding, and trigger squeeze.
To execute the movements without cartridges, first withdraw magazine, open chambers, and examine both pistols and magazines to assure that none contain ball cartridges.
not so loaded.
650. All the movements in loading pistol should be practiced without kxDking at it. In order to do this successfully it is necessary to know exactly where the magazines are carried so the hand may find them without fumbling. Also, since the projection at the front of the magazine base is on the same side as the bullets, and the magazine must be inserted in the socket with these to the front, the magazine should be carried in the pocket with the projection to the left and should be withdrawn from the pocket with the same grasp as is prescribed for icithdraw magazine.
651. This manual must be practiced with all the precision and exactness required for the manual for the rifle. Accidents will be reduced to a minimum and familarity with the pistol gained.
the right hand and grasp the stock, back of hand outward. .
At the command pistol, draw the pistol from the holster, reverse it, muzzle up, the hand holding the stock with the thumb and last three fingers; forefinger outside of the guard; barrel to the rear, and inclined to the front at an angle of about 30 degrees ; hand as high as the neck and 6 inches in front of the point of the right shoulder. This is the position of raise pistol, and it may be similarly taken from any position.
With tip
of right forefinger press stud releasing magazine, and then catch magazine with little finger under projection at front of magazine base. Raise magazine about an inch, then close tlr,;mb and second finger on sides of magazine, giving a secure grasp with which it can be withdrawn from socket and placed inside belt (in pocket of shirt or otherwise disposed of without throwing it av.-ay). Ilight hand then grasps stock, back of hand to the left.
2. Chamber.
' Carry the pistol to the left hand (if not already there) barrel to the left, frciit end of slide grasped between the thumb and forefinger of left hand ; right hand grasping stock, back of hand up: right thumb under slide stop. Hold left hand steady and push forward with right hand till slide reaches end of stroke; engage slide stop, and come to raise pistol. Should the pistol be cocked and locked, it must be unlocked, so that the slide can move.
1. Close, 2. Chambee.
At the connnand eliamher, release slide stop with right thumb and let hammer down gently. To let hammer down, pull dowmward with point of right thumb till hammer presses against grip safety and forces it home; then while continuing this pressure on hammer, pull trigger ; and while continuing pull on trigger let the hammer down. While letting hammer down, grasp stock firmly ])etween the palm and last three fingers to prevent pistol rotating in hand.
magazine in socket : 1. Insert, 2. Magazine.
Lower pistol into left hand as in witMraw magazine, grasp magazine with tip of right forefinger on projection at base of magazine, withdraw from pocket, and insert in pistol. To make sure that magazine is home strike base of magazine with palm of right hand. Bring the pistol to the position of raise pistol. 33325°— 18 11
Pistol.
Lower the pistol and raise tlie flap of the holster with the right thumb ; insert the pistol in the holster and push it down ; button the flap with the right hand. If the pistol be loaded and cocked, the command, 1. Lock, 2. Pistol, must precede the command " Return."
position, chamber empty: 1. Load, 2. Pistol.
Place pistol in left hand, barrel down, butt of pistol up, barrel pointing to left front and downward, slide grasped between thumb and forefinger. Push forward with right hand until the slide is fully open, then release slide, allowing it to move forward, and load cartridge into chaml^er. Come to raise pistol. If the last shot in the magazine has been fired, to reload; same command, but execute witlidraic magazine, insert magazine, close chamher. As soon as the pistol is loaded it will be immediately locked by the commands, 1. Lock, 2. Pistol. Should the command for locking pistol be inadvertently omitted it will be locked without command.
659. To unload pistol, being in any position, loaded : Execute by the commands, 1. Withdraic. 2. Magazine. 3. Open, 4, ChamEEE, 5. Close, 6. Chamber, 7. Insert, S. ^Magazine.
Magazine, 5. Open, 6. Chamber.
To avoid accidents, individual men out of ranks, in barracks, or camp will first witlidraic magazine, then open chamher, whenever the pistol is removed from the holster for cleaning, for examination, or for any oth-^r purpose. Accidental discharges will not occur if the above rule is always observed, and failure to observe it must be considered a military offense, whether or not accident results.
the arm is extended toward the target ; the feet far enough apart Mahout S to 10 inches) as to insure steadiness; weiglit of hody boruc equally upon both feet; riglit arm fully extended but not locked ; left arm hanging naturally.
THE GRIP.
662. Grasp the stock as higii as possible with the thumb and last three fingers, the forefinger alongside the trigger guard, the thumb extended along the stock. The barrel, hand, and forearm should be as nearly in one line as possible when the weapon is pointed toward the target. The grasp should not be so tight as to cause tremors, but should be firm enough to avoid losing grip. The lower the stock is grasped the greater will be the movement or jump of the muzzle caused by recoil. If the hand be placed so that the grasp is on one side of the stock, the recoil will cause a rotary movement of the weapon toward the opposite side.
The releasing of the sear causes a slight movement of the muzzle, generally to the left. The position and pressure of the thumb along the stock overcomes much of this movement.
To do uniform shooting the weapon must be held with exactly the same grip for each sliot, not only must the hand grasp the stock at th-7 same point for each shot, but the tension of the grip must be uniform.
THE TKIGGEll SQUEEZE.
663. The trigger must be squeezed in the same manner as in rifie firing. The pressure of the forefinger on the trigger should be steadily increased and should be straight back, not sideways. The pressure should continue to that point beyond which the slightest movement will release the sear. Then, when the aiu: is true, the additional pressure is applied and the pistol fired. When the pistol is fired the greatest effort should be taken to hold the pistol to the mark as nearly as possible. This will be of great benefit in automatic firing.
pasters are 10 paces distant from the squad. The instructor commands, 1. Raise, 2. Pistol, and cautions " Position and Aiming Drill." The men take the position prescribed in parata'aph 661. At the command : 1. Squad, 2. Fike, slowly extend the arm till it is nearlj' horizontal, the pistol directed at a point about 6 inches below the bull's-eye. At the same time put the forefinger inside the trigger guard and gradually feel the trigger. Inhale enough air to comfortably till the lungs and gradually raise the piece until the line of sight is directed at the point of- aim, i. e.. just below the bull's-eye at 6 o'clock, \yhile the sights are directed upon the mark, gradually increase the pressure on the trigger until it reaches that point where the slightest additional pressure will release the sear. Then, when the aim is true, the additional pressure necessary to fire tlie piece is applied so as not to derange the alignment of the sights. The weapon will be held on the mark for an instant after the hammer falls and the soldier will observe what effect, if any, the squee7.ing of the trigger has had on his aim.
QUICK FIKE.
665. Being at the 7'aisc pistol, chamber and magazine empty : 1. Quiclc-fire exercise, 2. One. Lower the forearm until it is nearly horizontal, pistol pointing at the target, 3. Two. Thrust the pistol forward to the position of aim. siiapping the pistol just before the arm reaches its full extension. Then look through sights to verify the pointing. 4. Theee.
In this exercise the soldier must keep his eyes fixed upon the mark. He should constantly practice pointing the pistol until he acquires the ability to direct it on the mark in the briefest interval of time and practically without the aid of the sigiits. In other words, the pistol in this exercise is accurately pointed instead of accurately aimed. In night firing pointing the pistol is the only method that can be used. After careful practice in this exercise it is surprising what good results can be obtained at night.
666. Boiii,!! at raise pistol, the pistol loaded and locked: To fire: With the rii;ht thumb release the safety lock, if in the locking position ; extend the arm, hrini;ing- the sights on the target, and press the trigger.
Tlie energy of recoil causes the mechanism of tlie pistol to eject the empty cartridge case, load, and prepare the pistol for the next shot. Pressure must be entirely relieved from the trigger after each shot in order that the trigger may reengage the sear. At the firing of the last cartridge, as the slide moves to the rear, it is automatically locked in the open position by the slide stop, thus calling attention to the fact that the magazine is empty.
FlPvE.
At the command ready the pistols are cocked or the safety hitches are released. At the command fire, each man aims and fires by steadily increasing the pressure of his grip. It is important that no attempt be made to pull the trigger.
669. As soon as practicable the recruit is taught the use, nomenclature, and care of his rifie. When fair progress has been made in the instruction without arms, he is taught the manual of arms. Instruction without arms and that with arms alternate.
all other times it is carried unlocked, with the trigger palled.
Second. Whenever troops are formed under arms, pieces are immediately inspected at the commands: 1. Inspection, 2. Akms, 3. Order {rigid shouUlcr, port). 4. Aems.
on guard, or for combat.
Fifth. Fall in is executed with the piece at the order arms. Fall out, rest, and at ease are executed as without arms. On resuming attention the position of order arms is taken.
Sixth. If at the order, unless otherwise prescribed, the piece is brought to the right shoulder ;it the command march, the three motions corresponding with the first three steps. Movement.s may be executed at the trail by prefacing the preparatory command with the words at frail: as. I. At trail, foricard. 2. M.'UJCii ; the trail is taken at the command march.
When the facings, alignments. oi)en and cl(;se ranks, taking intervals or distances, and assemblings are executed from the ordei*, raise the piece to the trail while in motion and resume the order on halting.
of arms :
First. In all po.sitions of the left hand at the balance (center of gravity, bayonet unfixed) the thumb clasps the piece; the sling is included in tlie grasp of the hand.
nbont 3 inches from the ^iround, barrel to the rear, the left haiul above and near the right, steadying the piece, fingers extended and .joined, forearm and wrist i^traight and inclining downward, all fingers of the right hand grasping the piece. To complete the order, lower the piece gently to the ground with the right hand, drop the left quickly by the side, and take the position of order arms.
Allovring the piece to drop througii the right hand to the ground, or other similar abuse of the rifle to produce effect in executing the manual, is prohibited.
Fourth. Tlie cadence of the motions is tiiat of quick time ; the recruits are first required to give their whole attention to the details of the motions, the cadence being gradually acquired as they become accustomed to handling their pieces. The instructor may require them to count aloud in cadence with the motions.
Fifth. The manual is taught at a halt and the movements are, for the purpose of instruction, divided into motions and executed in detail : in this case the ccmnuand of execution determines the prompt execution of the first motion, and the commands two, three, four, that of the other motions.
To execute the movements in detail, the instructor first cautions: By the nurdhers; all movements divided into motions are then executed as above explained until he cautions : Witliout the numhers; or commands movements othei> than those in the manual of arms.
Sixtli. Whenever circumstances require, the regular positions of the manual of arms and the firings may be ordered without regard to the previous position of the piece.
may be carried in any manner directed.
672. Position of order arins standing: The butt rests evenly on the ground, barrel to the rear, toe of the butt on a line with toe of, and touching, the right shoe, arms and hands hanging naturally, right hand holding the piece between the thumb and fingers.
674. Being at order .arms: 1. Port, 2. ApwMS.
With the right hand raise and throw the piece diagonally across the body, grasp it smartly with both hands ; the right, palm down, at the small of the stock ; the left, palm up, at the balance ; barrel up. sloping to the left and crossing opposite the junction of the neck with the left shoulder ; riglit forearm horizontal : left forearm resting against the body ; the piece in a vertical plane parallel to the front.
Let go with the right hand ; lower and carry the piece to the right with the left hand; regrasp it with the right hand just above the lower band ; let go with the left hand and take the next to the last position in coming to the order. (Two) Complete the order.
With the right hand raise and throw the piece diagonally
across the body : carry the right hand quickly to the butt, embracing it. the lieel ItetVNoen the first two fingers. (Two) Without changing the grasp of the right hand, place the piece on the right slioulder, barrel up and inclined at an angle of about 4-5 degrees from the horizontal, trigger guard in the hollow of the shouhler, right elbow near the side, the piece in a vertical plane perpendicular to the front; carry the left hand, thumb and fingers extended and joined, to the small of the stock, tip of the forefinger touching the cocking piece, wrist straight and elbow down. (Theee) Drop the left hand by the side.
Carry the piece with the right hand and place it on the left shoulder, barrel up, trigger guard in the hollow of the shoulder ; at the same time grasp the butt with the left hand, heel between first and second fingers, thumb and fingers closed on the stock. (Two) Drop the right hand by the side.
Grasp the piece with the right hand at the small of tlic stock. (Two) Carry the piece to the right with the right hand, regrasp it with the left, and take the position of port arms.
Left shouhler arms may be ordered directly from the order right shoulder or present, or the reverse. At the command arms execute port arms and continue in cadence to the position ordered.
Carry the right foot 6 inches straight to the rear. left knee slightly bent ; carry the muzzle in front of the ceiUer of the body, barrel to the left; grasp the piece with the left }i:uid just below the stacking swivel, and with the right hand below and against the left.
688. Being at right shoulder arms : 1. Rifle, 2. Salute.
Carry the left hand smartly to the small of the stock, forearm horizontal, palm of hand down, thumb and forefingers extended and joined, forefinger touching end of cocking piece; look toward the person saluted. (Two) Drop left hand by the side; turn head and eyes to the front.
Carry the left hand smartly to the right side, palm of the
hand down, thumb and lingers extended and joined, forefinger against piece near the muzzle; look toward the per.son saluted. (Two) Drop the left hand by the side; turn the head and eyes to the front.
If the bayonet scabbard is carried on the belt : Execute parade rest ; grasp the bayonet Avith the right hand, back of hand toward the body; draw the bayonet from the scal)bard and fix it on the barrel, glancing at the nuizzle; resume the order.
If the bayonet scabbard is carried on the belt: Execute
parade rest ; grasp the handle of the bayonet firmly with the right hand, pressing the spring with the forefinger of the right hand : raise the bayonet until the handle is about 12 inches above the muzzle of the piece; drop the point to the left, back of the baud tov/ard the 1iody, and. glancing at the scabbard, return the bayonet, the blade, passing between the left
resume the order.
If the bayonet scabbard is carried on the haversacl^ : Take the bayonet from the rifle with the left hand and return it to tlie scabbiird in the most convenient manner.
If marching or lying down, the bayonet is fixed and unfixed in tlie most expeditious and convenient manner and the piece returned to the original position.
regularity, but not in cadence.
1911 rifle. — If the bayonet scabbard is carried on the belt : Execute parade rest ; grasp the handle of the bayonet firmly with the right hand, pressing the spring with the forefinger of the left hand ; raise the bayonet until the handle is about 12 inches above the muzzle of the piece ; drop the point to the left, back of the hand toward the body, and, glancing at the scabbard, return the bayonet, the blade passing between the left arm and the body ; regrasp the piece with the right hand and resume the order.
692. Charge Bayonet. — Whether executed at halt or in motion, the bayonet is held toward the opponent as in the position of guard in the Manual for Bayonet Exei*cise.
At the second conniiand take the position of port arms. (Two) Seize the bolt handle with the thumb and forefinger of the right hand, turn the handle up, draw the bolt back, and glance at the chamber. Having found the chamber empty, or having emptied it, raise the head and eyes to the front.
1003 rifle. — At the preparatory command push the bolt forward, turn the handle down, pull the trigger, and resume port a^rms. At the command arms, complete the movement order(;d.
ward just enough to engage the follower, raise the fingers of the left liand. push the bolt forward, turn the handle down, pull the trigger, and resume vort arms. At the command arms complete the movement ordered.
696. The squad being in line at a halt: Stack Ar.MS.
Each even number of the front rank grasp:^ his piece with the left hand at the upper band and rests the b;itt between his feet, barrel to the front, muzzle inclined slightly to the front and opposite the center of the interval on his right, the thumb and forefinger raising the stacking swivel ; each even number of the rear rank then passes his piece, barrel to the rear, to his file leader, who grasps it between the bands with his right hand and throws the Initt about 2 feet in advance of that of his own piece and opposite the right of the interval, the right hand slipping to the upper band, the thumb and forefinger raising the stacking swivel, which he engages with that of his own piece; each odd number of the front rank raises his piece with the right hand, carries it well forward. barr»^l to the front; the left hand, guiding the stacking sv.'ivel. engages the lower hook of the swivel of his own piece with the free hook of that of the even number of the rear rank ; he then turns the barrel outvrard into the angle formed by the other two pieces and lowers the butt to the ground, to the right of and against the toe of his right shoe.
The loose pieces are returned by the even numbers of the
front rank : each even number of the front rank grasps his own piece with the left hand, the piece of his rear-rank man with his right hand, grasping both between the bands ; each odd number
of the front rank grasps his piece in the same way with the right hand, disengages it hy raising the butt from the gi'ound and then, turning the piece to the right, detaclies it from the stack ; each even number of the front rani-: disengages and detaches his piece by turning it to tlie left, and then passes the piece of his rear-rank man to him and all resume the order.
698. Should any squad have Nos. 2 and 3 blank files. No. 1 rear rank takes the place of No. 2 rear rank in making and breaking the stack ; the stacks made or broken, he resumes his post.
loading. Loadings are executed in line and skirmish line only.
700. Pieces having been ordered loaded are kept loaded without command until the command unload, or inspection arms, fresh clips being inserted when the magazine is exhausted.
701. The aiming point or target is carefully pointed out. This may be done before or after announcing the sight setting. Both are indicated before giving the command for firing, but may be omitted when the target appears suddenly and is unmistakable ; in such case battle sight is used, if no sight setting is announced.
702. The target or aiming point having been designated and the sight setting announced, such designation or announcement need not be repeated until a change of either or both is necessary.
1903 rifle. — At the command load each front-rank man or skirmisher faces half right and carries the right foot to the right, about 1 foot, to such position as will insure the greatest firmness and steadiness of the body ; raises or lowers the piece and drops it into the left hand at the balance, left thumb extended along the stock, muzzle at the height of the breast, and turns the cutoff up. With the right hand he turns and draws the bolt back, takes a loaded clip and inserts the end in the clip slots, places the thumb on the powder space of the top cartridge, the fingers extending around the piece and tips resting on the magazine floor plate ; forces the cartridges into the magazine by pressing down with the thumb ; without removing the clip, thrusts the bolt home, turning down the handle; turns the safety lock to the " Safe " and carries the hand to the small of the stock. Each rear-rank man moves to the right front, takes a similar position opposite the interval to the right of his front-rank man, muzzle of the piece extending beyond the front rank, and loads.
lOl": rifle. — At the command load each front-rank man or skirmisher faces half right and carries the right foot to the right, about 1 foot, to such position as will insure the greatest firmness and steadiness of the body ; raises or lowers the piece and drops it into the left hand at the balance, left thumb extended along the stock and the muzzle at the height of the breast. With the right hand he turns and draws the bolt back, takes a loaded clip and inserts the end in the clip slots, places the thumb on the powder space of the top cartridge, the fingers extending around the piece and tips resting on the magazine fioor plate ; forces the cartridges into the magazine by pressing down with the thumb ; without removing the clip, thrusts the bolt home, turning down the handle ; turns the safety lock to the " Safe " and carries the hand to the small of the stock. Each
rear-rank man moves to the right front, takes a similar position opposite the interval to the right of his front-rank man, muzzle of the piece extending beyond the front rank, and loads.
as nearly as practicable in the position of load.
If kneeling or sitting, the position of the piece is similar; if kneeling, the left forearm rests on the left thigh ; if sitting, the elbows are supported by the knees. If lying down, the left hand steadies and supports the piece at the balance, the toe of the butt resting on the ground, the muzzle off the ground.
cartridges may be used.
707. Unload. — Take the position of load, turn the safety lock up and move the bolt alternately backward and forward until all the cartridges are ejected. After the last cartridge is ejected the chamber is closed by pressing the follower down with the fingers of the left hand, to engage it under the bolt, and then thrusting the bolt home. The trigger is pulled. The cartridges are then picked up, cleaned, and returned to the belt, and the piece is brought to the order.
repeats same, if necessary, or commands : Suspend Firing.
Firin? stops ; pieces are held, loaded and locked, in a position of readiness for instant resumption of firing, rear sights unchanged. The men continue to observe the target or aimin.2: point, or the place at which the target disappeared, or at which it is expected to reappear.
Firing stops; pieces are loaded and locked ; the sights are laid down, and the piece is brought to the order. Cease tiring is u.sed for long pauses to prepare for changes of position or to steady the men.
712. Commands for suspending or ceasing fire may be given at any time after the preparatory command for firing whether the firing has actually commenced or not.
713. In order to keep the rifle in good working condition, it is necessary that it be kept well oiled and cleaned. The rifle should be inspected each day during campaign to insure that the mechanism is working properly and that the cartridges in the magazine have not become rusted.
The rifle should never be placed where it can fall and injure the sights ; it should never be placed in the bottom of a wagon where the jolting will injure the sights.
weather or when the dust is blowing, except in case of necessity.
Great care should be taken to avoid getting dust or mud in the ■ mechanism. Dust in the breech mechanism will cause this mechanism to fail to function; the bolt will not open and the gun will be useless to the operator.
A rag: sboiild never be put in the nniz;:le of a gun in order to keep out dampness, because a rag will invariably collect moisture, and the result will be a rusty bore at that point.
In a windy and dusty country, it is a wise precaution to cut the toe out of a sock and slip the sock over the breech mechanism. This will keep out dust and the sock can easily and quickly be removed. In trenches, where mud is plentiful, the use of the sock will keep mud out of the breech mechanism. Mud or a rag in the muzzle is very dangerous, and if the gun bo fired it will inevitably result in bursting the barrel or some part of the breech mechanism.
In case of gas coming in contact with the gun — either from gas shells or a gas attack — it is imperative that the gun be cleaned immediately after such attack and thorouglily oiled.
The chamber of a gun is the part that will ordinarily give the most trouble in service. Dust, dirt, sand, mud. and rust all cause the chamber to grip the cartridge tightly, and in many cases it will be impossible to extract the shell from the chamber. The chamber should be cleaned vviienever the gun is cleaned.
At the command drair, unhook the saber with the thumb and first t\vo fingers of the left hand, thumb on the end of the hook, fingers lifting the upper ring; grasp the scabbard with the left hand at the upper band, bring the hilt a little forward, seize the grip with the right hand, and draw the blade 6 inches out of the scabbard, pressing the scabbard against the thigh with the left hand.
degrees with the horizontal, the saber, edge down, in a straight line with the arm ; mal^e a slight pause and bring back of the blade against the shoulder, edge to the front, arm nearly extended, hand by the side, elbow back, third and fourth tingers back of the grip ; at the same time hook up the scabbard with the thumb and first two fingers of the left hand, thumb through the upper ring, fingers' supporting it ; drop the left hand by the side.
This is the position of carry saber dismaiintcd.
Officers and noncommissioned officers armed with tlie saber unhook the scabbard before mounting; when mounted, in the first motion of drair saber they reach with the right hand over the bridle hand and without the aid of the bridle hand draw the saber as before; the right hand at the c<irry re5?ts on the right thigh.
On foot the scabbard is carried hooked up.
715. When publishing orders, calling the roll, etc., the saber is held suspended from the right wrist by the saber knot ; when the saber knot is used it is placed on the wrist befoi-^ drawing saber and taken off after returning saber.
At the command prcsc7it. raise and carfy the saber to the front, base of the hilt as high as the chin and 6 inches in front of the neck, edge to the left, point 6 inches farther to the front than the hilt, thumb extended on the left of the grip, all fingers gra.«;ping the grip.
At the conuuand "labcr, or arms, lower the saber, point in prolongation of the right foot and near the ground, edge to the left, hand by the side, thumb on left of grip, arm extended. If mounted, the hand is held behind the thigh, with the point a little to the right and front of the stirrup.
In rendering honors with troops officers execute the first motion of the salute at the command present, the second motion at the command arws: enlisted men with the saber execute the first motion at the command arms and omit the second motion.
Bein,::; at the present saber, should the next command be order arms ofTicers and noncommissioned officers armed with the saber order saber; if the command be other than order arr)\s, they execute carry saber.
Take the position of parade rest, except that the left hand is uppermost and rests on the right hand, point of saber on or near the ground in front of the center of the body, edge to the right.
the scabbard.
721. Officers and noncommissioned officers armed with the saber, on all duties under arms, draw and return saber without waiting for command. All commands to soldiers under arms are given with the saber drawn.
722. Being at a carry : 1. Return, 2. Saber.
At the command return carry the right hand opposite to and 6 inches from the left shoulder, saber vertical, edge to the left ; at the same time unhook and lower the scabbard with the left hand and grasp it at the upper band.
At the command saber drop the point to the rear and pass the blade across and along the left arm ; turn the head slightly to the left, fixing the eyes on the opening of the scabbard, raise the right hand, insert and return the blade ; free the wrist from the saber knot (if inserted in it), turn the head to the front, drop the right hand by the side; hook up the scabbard with the left hand, drop the left hand by the side.
Officers and noncommissioned officers armed with the saber, when mounted, return saber without using the left hand; the scabbard is hooked up on dismounting.
723. At inspection enlisted men with the saber drawn execute the first motion of present saber and turn the wrist to show both sides of the blade, resuming the earry when the inspector has passed.
TO MAKE CAMP.
724. The captain indicates the site for the tents, the picket line, and the parlv. and comniands : Make Camp. The picket line is then placed in position, wagons unloaded, animals, carts, and guns are cared for, after which tents are pitched.
SHELTER TENTS.
725. The shelter tont or temporary camp is used in the field when halts are not to be of snlTicient duration to justify the bringing up of semipermanent camp equipage, or when same is not available. The\- will of necessity vary greatly in form, dimensions, and area occupied, and in the means available for the improvisation of camping expedients. The regulations and plates prescribed are given as conforming to usual conditions and should govern in all instruction in the selection and occupation of shelter-tent camp sites. In actual service the dispositions in camp must be adapted to the ground and must be made so as to derive the maximum benefit from the meager camp equipn-ent carried. The camp will in this latter instance, therefore, sc idom be ideally regular. Whenever possible, companios should be camped in line or in column of platoons. The principal advantage accruing in camping in column is the freedom afforded for withdrawing independent platoons from camps when it is desired to send them on detached missions.
TO PITCH SHELTEB TENTS.
726. Being in line or in column of platoons : Form for Shelter Tents. Each section leader arranges for pairing odd men in his squads as far as practicable. If after this has been done any man in the section, including the section leader, remains unpaired, the first sergeant is notified. Having arranged pairs between the men left over in the several sections, the first sergeant reports the company formed, and, with the company clerk, with whom the first sergeant pitches, takes his place to the right of the headquarter's detail. The first sergeant having re-
ported, the officer in charge causes the compauy to take intervals as prescribed in the squad (94). As each man faces to the front he places his pack and other equipment on the ground.
727. The officer aligns the men and commands : Pitch Tents. The men open their packs and take out the shelter half, poles and pins ; the front-rank man places one pin in the ground at the point where his right heel, kept in position until this time, was planted. Each then spreads his shelter half, triangle to the rear, flat upon the ground the tent is to occupy, rear man's half on the right. The halves are then buttoned together. Each front-rank man joins his pole, inserts the top in the eyes of the halves, and holds the pole upright beside the pin placed in the ground ; his rear-rank man. using the pins in front, pins down the front corners of the tent on the line of pins, stretching the canvas taut ; he then inserts a pin in the eye of the rope and drives the pin at such distance in front of the pole as to hold the rope taut. Both then go to the rear of the tent ; the rear-rank man adjusts the pole and the front-rank man drives the pins. The rest of the pins arc then driven by both men, the rear-rank man working on the right.
729. The double shelter tent is formed by buttoning together the square ends of two single tents. Two complete tents, except one pole, are used. Two guy ropes are used at each end, the guy pins being placed in front of the corner pins.
The double shelter tents are pitched by Nos. 1 and 2 front and rear rank, and by Nos. 3 and 4, front and rear rank ; the men falling in on the left are numbered, counting off if necessary.
the tent pin.
All the men spread their shelter halves on the ground the tent is to occupy. Those of the front rank are placed with the triangular ends to the front. All four halves are then buttoned together, first the ridges and then the square ends. The front corners of the tent are pinned by the front-rank men, the odd number holding the poles, the even number driving the pins. The rear-rank men similarly pin the rear corners.
While the odd numbers steady the poles, each even number of the front rank takes his pole and enters the tent where, assisted by the even number of the rear rank, he adjusts the pole to the center eyes of the shelter halves in the following order : First, the lower half of the front tent ; second, the lower half of the rear tent; third, the upper half of the front tent; fourth, the upper half of the rear tent. The guy ropes are then adjusted.
SINGLE SLEEPING BAG.
730. Spread the poncho on the ground, buttoned at the feet, button side to the left ; fold the blanket once across its short dimension and lay it on the poncho, folded side along the right side of the poncho ; tie the blanket together along the left side by means of the tapes provided ; fold the left half of the poncho over the blanket and button it together along the side and bottom.
731. Spread one poncho on the ground, button end at the feet, button side to the left ; spread the blankets on top of the poncho : tie the edges of the blankets together with the tapes provided ; spread a second poncho on top of the blankets, button end at the feet, button side to the right ; button the two ponchos together along both sides and across the end.
733. To pitch all types of army tents, except shelter tents: INIark each line of tents by driving a vrall pin at the spot to be occupied by the right (left) corner of each tent. P'or pyramidal tents the interval 1)etween adjacent pins should be about 30 feet, which will give a passage of 2 feet betw^een tents. If the tripod is used, spread it on the ground where the center of the tent is to be. Spread the tent on the ground to be occupied, door to the front, and place the right (left) front wall loop over the pin. The door (or doors, if more than one) being fastened and held together at the bottom; the left (right) corner wall loop is carried to the left (right) as far as it will go and a wall pin driven through it, the pin being placed in the line with the right (left) corner pins already driven. At the same time, the rear corner wall loops are pulled to the rear and outward, so that the rear and side walls of the tent are stretched. Wall pins are then driven through these loops directly in rear of the corresponding front corner pins, making a rectangle. Unless the canvas be wet. a small amount of slack should be allowed before the corner pins are driven. According to the size of th.e tent, one or tv\'o men, crawling under the tent if necessary, lit each pole or ridge or upright into the ring or ridge-pole holes, and such accessories as hood. fly. and brace ropes are adjusted. If a tripod be used, an additional man will go under the tent to adjust it. The tent, steadied by the remaining men, one at each corner guy rope, will then be raised. If the tent is of the ward or storage type, corner poles will nov/ be placed at the four corners. The four corner guy ropes are then placed over the lower notches of the large pins driven in prolongation of the diagonals at such distance as to hold the walls and ends of the tent vertical and smooth when the guy ropes are drawn taut. A wall pin is then driven through each remaining wall loop, and a large pin for each guy rope is driven in line with the corner guy pins already driven.
The guy ropes of the tent are placed over the lower notches, while the .sruy ropes of the fiy are placed over the upper notches and are then drawn taut. Brace ropes, when used, are then secured to stakes or pins suitably placed.
or placed in their receptacle.
One man holds each guy and when the ground is clear the tent is lowered and folded or rolled and tied, the poles or tripod and poles fastened together, and the remaining pins collected.
TO FOLD TENTS.
735. Common, wall, hospital, and storage tents. — Spread the tent tlat on the gi'ound, folded at the ridge so that bottoms of the side walls are even, ends of the tent forming triangles to the right and left ; fold the triangular ends of the tent in toward the middle, making it rectangular in shape; fold the top over about 9 inches; fold the tent in two by carrying the top fold over clear to the foot; fold again in two from the top to the foot; throw all guys on tent except the second from each end ; fold the ends in so as to cover about two-thirds of the second widths of canvas; fold tlie left end over to meet the turned-in edge of the right end. then fold the right end over the top. completing the bundle ; tie with the two exposed guys.
Pyramidal tent. — The tent is thrown toward the rear, and the back wall and roof canvis pulled out smooth. This may be most easily accomplished by leaving the rear corner wall pins in the ground with the wall loops attached, one man at each rear corner guy. and one holding the square iron in a perpendicular position and pulling the r-anvas to its limit away from the former front of the tent. This leaves the three remaining sides of the tent on top of the rear side, with the door side in the middle.
Now carry the right front corner over and lay it on the left rear corner. Pull all canvas smooth, throw guys toward square iron, and pull bottom edges even. Then take the right front
corner and return to the right, covering the right rear corner. This folds the right side of the tent on itself, with the crease in the middle and under the front side of the tent.
Next carry the left front corner to the right and back as described above; this when completed will leave the front and real' sides of the tent lying smooth and flat and the two side walls folded inward, each on itself.
Place the hood in the square iron which has been forced downward toward the bottom of the tent, and continue to fold around the square iron as a core, pressing all folds down flat and smooth and parallel with the bottom of the tent. If each fold is compactly made and the canvas kept smooth, the last fold will exactly cover the lower edge of the canvas# Lay all exposed guys along the folded canvas except the two on the center width, which should be pulled out and away from bottom edge to their extreme length for tying. Now, beginning at one end, fold tov/ard the center on the first seam (that joining the first and second widths) and fold again toward the center so that the already folded canvas will come to within about 3 inches of the middle width. Then fold over to the opposite edge of middle width of canvas. Then begin folding from opposite end, folding the first width in half ; then, making a second fold to come within about 4 or 5 inches of that already folded, turn this fold entirely over that already folded. Take the exposed guys and draw them taut across each other, turn bundle over on the under guy, cross guys on top of bundle, and draw tight. Turn bundle over on the crossed guys and tie lengthwise.
| 74,351 | common-pile/pre_1929_books_filtered | machinegundrillr00unit | public_library | public_library_1929_dolma-0023.json.gz:4798 | https://archive.org/download/machinegundrillr00unit/machinegundrillr00unit_djvu.txt |
RffBqxuq6lmVx9WQ | Building Information Modeling using Revit for Architects and Engineers | Chapter 14: Site Modeling
3D site modeling covers all elements added around the building structure including vegetation, infrastructure, vehicles, and contouring land or topography. 2D site design consists of property lines, topography lines, and the building pad. A building pad is required when topography is added to a 3D model because it can cut through the topography where a floor is not able to.
There are 3 methods for creating topography in Revit.
- Placing points at a specific location and assigns each point an elevation height
- Import a CAD filed that has lines or points with assigned elevations, usually acquired from a GIS shapefile.
- Import a CAD file that has been generated by a civil engineering program.
14.1 Create topography with CAD import
- In the Project Browser, double click Site under the Floor Plans section
- In the View tab, click the Import CAD icon
- Select the Topography file that was downloaded from Canvas
- Click Open
TIP
If the topography does not appear at the top of Level 1 change the Top Offset to a negative number until it is just above the floor. This example was adjusted to -48’ 6” - Open the 3D view from the Project Browser
- Click the Massing & Site tab
- Click the Toposurface icon
- Under the Tools panel, click the Create from import drop-down menu
- Click the Select Import Instance
- Select the linked CAD file
- In the Add Points from Select Layers window, uncheck the 0 layer
- Click OK
- Click the green checkmark to finish
TIP
These CAD files may have too many points and can be simplified by clicking the Simply surface icon
Figure 14.1 Toposurface created using a linked CAD file.
Add a Building Pad to the Imported CAD file Toposurface
- In the Site view go to the Massing & Site tab
- Click the Building Pad icon
- Use the Pick Lines tool to select the edges of the roof and floors that are visible then clean up the lines using the Trim tool
- Click the green checkmark to finish drawing the building pad
Figure 14.2 Building Pad cutting through the CAD imported topography
14.2 CREATE TOPOGRAPHY BY PLACING POINTS
- Open the Site view
- Click the Massing & Site tab
- Click the Toposurface icon
- Click the Place Point icon
- On the Options Bar change the elevation to 0’ 0”
- To the right of the existing model click to place a nonlinear line similar to Figure 14.3
- Change the Elevation to 10’ 0” and create another nonlinear line
- Continue to complete lines with 20’, 30’, 30’, and 0’ elevations
- Click the green checkmark to finish the toposuface
Figure 14.3 Toposurface created by placed points
TIP
14.3 ADD A BUILDING PAD
- In the Site view go to the Massing & Site tab
- Click the Building Pad icon
- Use the Rectangle tool to draw a shape between the 20 and 30-foot levels as shown in Figure 14.4
Figure 14.4 Building Pad drawn in the Site view - Click the green checkmark to finish drawing the building pad
- Select the building pad and change the Level to see how the toposurface responds to the building pad.
- Use the Section box to cut through the Building pad
Figure 14.5 Building Pad at Level 2 with a section box cutting the toposurface | 747 | common-pile/pressbooks_filtered | https://uta.pressbooks.pub/buildinginformationmodeling/chapter/chapter-14-site-modeling/ | pressbooks | pressbooks-0000.json.gz:14309 | https://uta.pressbooks.pub/buildinginformationmodeling/chapter/chapter-14-site-modeling/ |
wR6VpLlh9p-vhHaA | 1.5: Key Terms | Skip to main content
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determinants
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factors that influence health; can include events, characteristics, or other entities that change a health condition or the level of a health problem
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disability-adjusted life years (DALYs)
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estimates the number of healthy years lost across the population due to premature death and disability from a select condition
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disparities
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inequalities or differences
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downstream
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describes interventions that focus on the behavior of individuals to modify the risk of disease, prevent illness, or manage chronic conditions
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general mortality
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the number of deaths across a large population, such as a geographic region or country, reports of which include information about leading causes of death across the population and estimates of years of potential life lost when people die prematurely
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global nursing
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the use of evidence-based nursing processes to promote sustainable planetary health and equity for all people
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health care continuum
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the spectrum of health care services delivered in public health, acute care, ambulatory care, and long-term care settings
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health care utilization
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the extent to which a population accesses and uses different health care services
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health inequities
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avoidable inequalities related to health that stem from a form of injustice
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infant mortality
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the rate of infants who die before their first birthday
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life expectancy
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the average number of years a newborn is expected to live if current death rates remain constant
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midstream
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describes interventions that occur within a specific organization
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morbidity rate
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the prevalence or incidence of a specific health condition, disease, or diagnosis within the population
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outcomes
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in a population health context, all possible results that may come from exposure to interventions aiming to prevent or treat a condition
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population
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a group of people that may receive care in various settings at the local, regional, national, and global levels
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population health
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an approach to supporting the health of people through research, data analysis, and health programming that considers the impact of public policy and environmental, social, behavioral, and other factors that might facilitate or hinder health for all
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quality of life
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indication of enjoyment and satisfaction people have, given their multidimensional experiences in health, relationships, activities, and life circumstances
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risk factors
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aspects of personal behaviors, lifestyle choices, exposures, or attributes that generally increase the likelihood or severity of acquiring a health condition
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social determinants of health
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conditions and social factors that affect outcomes and risk related to health, functioning, and quality of life
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transitional care
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efforts aimed at coordinating health care as clients receive services in various areas of the health care continuum
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upstream
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describes interventions that involve enacting policies that change regulations, increase access, or provide economic incentives to impact health across a population | 620 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Nursing/Population_Health_for_Nurses_(OpenStax)/01%3A_What_Is_Population_Health/1.05%3A_Key_Terms | libretexts | libretexts-0000.json.gz:1714 | https://med.libretexts.org/Bookshelves/Nursing/Population_Health_for_Nurses_(OpenStax)/01%3A_What_Is_Population_Health/1.05%3A_Key_Terms |
P4VA68PssKYOtPF6 | The Poetic Sequence: An Open Anthology | A Street in Bronzeville (1945)
Gwendolyn Brooks
This sequence of poems is arranged as it was in Gwendolyn Brooks’ eponymous 1945 collection, A Street in Bronzeville. In later anthologies of her work, and online, editors have divorced the poems from the larger sequence, as too often happens. Reading them together in the original order, one can see how they build upon one another for emotional and lyric effect. Brooks’ estate holds the copyright on these poems, so I have pulled them together via links from disparate sites. You can click the links below to read them in order. I have also pulled them together in a single document here for ease of reading.
the old marrieds
kitchenette building
the mother
southeast corner
hunchback girl: she thinks of heaven
a song in the front yard
the ballad of chocolate Mabbie
the preacher: ruminates behind the sermon
Sadie and Maud
the independent man
when you have forgotten Sunday: the love story
of De Witt Williams on his way to Lincoln Cemetery
the vacant lot
References
- “the old marrieds,” copyright by Gwendolyn Brooks, is available through the Chicago Literary Archive.
- “kitchenette building,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website.
- “the mother,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website.
- “southeast corner,” copyright by Gwendolyn Brooks, is available at the Morgan Library and Museum.
- “hunchback girl: she thinks of heaven,” copyright by Gwendolyn Brooks, is available through the Chicago Literary Archive.
- “a song in the front yard,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website.
- “the ballad of the chocolate Mabbie,” copyright by Gwendolyn Brooks, is available through the Chicago Literary Archive.
- “the preacher: ruminates behind the sermon,” copyright by Gwendolyn Brooks, is available through the Chicago Literary Archive.
- “Sadie and Maud,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website.
- “the independent man,” copyright by Gwendolyn Brooks, is available through the Chicago Literary Archive.
- “when you have forgotten Sunday: the love story,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website.
- “of De Witt Williams on his way to Lincoln Cemetery,” copyright by Gwendolyn Brooks, is available at the Morgan Library and Museum.
- “the vacant lot,” copyright by Gwendolyn Brooks, is available on the Poetry Foundation website. | 508 | common-pile/pressbooks_filtered | https://wisconsin.pressbooks.pub/poeticsequence/chapter/a-street-in-bronzeville-1945/ | pressbooks | pressbooks-0000.json.gz:87426 | https://wisconsin.pressbooks.pub/poeticsequence/chapter/a-street-in-bronzeville-1945/ |
GBlFPHHbkF5AHkQU | 25.6: Examples | 25.6: Examples
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- Last updated
- Save as PDF
Example \(\PageIndex{1}\): Calorimetry
The specific heat of aluminum is 900 J/kg·K, and that of water is 4186 J·K. Suppose you drop a block of aluminum of mass 1 kg at a temperature of 80\(^{\circ}\)C in a liter of water (which also has a mass of 1 kg) at a temperature of 20\(^{\circ}\)C. What is the final temperature of the system, assuming no exchange of heat with the environment takes place? How much energy does the aluminum lose/the water gain?
Solution
Let us call \(T_{Al}\) the initial temperature of the aluminum, \(T_{water}\) the initial temperature of the water, and \(T_f\) their final common temperature. The thermal energy given off by the aluminum equals \(\Delta E_{Al} = C_{Al}(T_f − T_{Al})\) (this follows from the definition ( 13.2.1 ) of heat capacity; we could equally well call this quantity “the heat given off by the aluminum”). In the same way, the thermal energy change of the water (heat absorbed by the water) equals \(\Delta E_{water} = C_{water}(T_f −T_{water})\). If the total system is closed, the sum of these two quantities, each with its appropriate sign, must be zero:
\[ 0=\Delta E_{\mathrm{Al}}+\Delta E_{\mathrm{water}}=C_{\mathrm{Al}}\left(T_{f}-T_{\mathrm{Al}}\right)+C_{\mathrm{water}}\left(T_{f}-T_{\mathrm{water}}\right) \label{eq:13.20} .\]
This equation for \(T_f\) has the solution
\[ T_{f}=\frac{C_{\mathrm{Al}} T_{\mathrm{Al}}+C_{\mathrm{water}} T_{\mathrm{water}}}{C_{\mathrm{Al}}+C_{\mathrm{water}}} \label{eq:13.21} .\]
As you can see, the result is a weighted average of the two starting temperatures, with the corresponding heat capacities as the weighting factors.
The heat capacities \(C\) are equal to the given specific heats multiplied by the respective masses. In this case, the mass of aluminum and the mass of the water are the same, so they will cancel in the final result. Also, we can use the temperatures in degrees Celsius, instead of Kelvin. This is not immediately obvious from the final expression (\ref{eq:13.21}), but if you look at (\ref{eq:13.20}) you’ll see it involves only temperature differences, and those have the same value in the Kelvin and Celsius scales.
Substituting the given values in (\ref{eq:13.21}), then, we get
\[ T_{f}=\frac{900 \times 80+4186 \times 20}{900+4186}=30.6^{\circ} \mathrm{C} \label{eq:13.22} .\]
This is much closer to the initial temperature of the water, as expected, since it has the greater heat capacity. The amount of heat exchanged is
\[ C_{\text {water }}\left(T_{f}-T_{\text {water }}\right)=4186 \times(30.6-20)=44,440 \: \mathrm{J}=44.4 \: \mathrm{kJ} \label{eq:13.23} .\]
So, 1 kg of aluminum gives off 44.4 kJ of thermal energy and its temperature drops almost 50\(^{\circ}\)C, from 80\(^{\circ}\)C to 30.6\(^{\circ}\)C, whereas 1 kg of water takes in the same amount of thermal energy and its temperature only rises about 10.6\(^{\circ}\)C.
Example \(\PageIndex{2}\): Equipartition of energy
Estimate the speed of an oxygen molecule in air at room temperature (about 300 K).
Solution
Recall that in Section 13.2 I mentioned that the average translational kinetic energy of a molecule in a system at a temperature \(T\) is \(\frac{3}{2}k_{B}T\) (Equation ( 13.2.7 ), where \(k_B\), Boltzmann’s constant, is equal to 1.38 × 10 −23 J/K. So, at \(T\) = 300 K, a molecule of oxygen (or of anything else, for that matter) should have, on average, a kinetic energy of
\[ \left\langle K_{\text {trans}}\right\rangle=\frac{3}{2} k_{B} T=\frac{3}{2} \times 1.38 \times 10^{-23} \times 300 \: \mathrm{J}=6.21 \times 10^{-21} \: \mathrm{J} \label{eq:13.24} .\]
Since \(K = \frac{1}{2}mv^2\), we can figure out the average value of \(v^2\) if we know the mass of an oxygen molecule. This is something you can look up, or derive like this: One mole of oxygen atoms has a mass of 16 grams (16 is the atomic mass number of oxygen) and contains Avogadro’s number of atoms, 6.02 × 10 23 . So a single atom has a mass of 0.016 kg/6.02 × 10 23 = 2.66 × 10 −26 kg. A molecule of oxygen contains two atoms, so it has twice the mass, \(m\) = 5.32 × 10 −26 kg. Then,
\[ \left\langle v^{2}\right\rangle=\frac{2\left\langle K_{\text {trans}}\right\rangle}{m}=\frac{2 \times 6.21 \times 10^{-21} \: \mathrm{J}}{5.32 \times 10^{-26} \: \mathrm{kg}}=2.33 \times 10^{5} \: \frac{\mathrm{m}^{2}}{\mathrm{s}^{2}} \label{eq:13.25} .\]
The square root of this will give us what is called the “root mean square” velocity, or \(v_{rms}\):
\[ v_{r m s}=\sqrt{2.33 \times 10^{5} \: \frac{\mathrm{m}^{2}}{\mathrm{s}^{2}}}=483 \: \frac{\mathrm{m}}{\mathrm{s}} \label{eq:13.26} .\]
This is of the same order of magnitude as (but larger than) the speed of sound in air at room temperature (about 340 m/s, as you may recall from Chapter 12). | 930 | common-pile/libretexts_filtered | https://phys.libretexts.org/Courses/Merrimack_College/Conservation_Laws_Newton's_Laws_and_Kinematics_version_2.0/25%3A_Thermodynamics/25.06%3A_Examples | libretexts | libretexts-0000.json.gz:11495 | https://phys.libretexts.org/Courses/Merrimack_College/Conservation_Laws_Newton's_Laws_and_Kinematics_version_2.0/25%3A_Thermodynamics/25.06%3A_Examples |
ZzcfzwM33SgWOaDQ | Western Civilization | 207 Module Overview
Module 6 contains the following content – all original by author or contained in the Lumen textbook.
Textbook Reading – Chapter 6, Julius Caesar-The Decline and Fall of the Roman Empire
Discussion Forum:
This discussion will be based on the textbook reading for the chapter. For your initial post in this discussion please answer the following questions: “Do you think the government and conditions in the Roman Empire were better or worse than those of the Republic? What were some of the advantages of rule by Emperor and what were some of the drawbacks?”
Initial posts must be at least 200 words in length and have at least one quote from the textbook.
After posting your initial post you are required to reply to at least one other student. Replies must be at least 100 words in length and have at least one new quote from the textbook (not a quote you used in your initial post and not a quote that is in the post you are replying to).
All posts must be made by the deadline for the discussion forum to receive full credit.
Short Essay:
Submit your short essay for Module #6 here. The question for this essay is: “Based on the textbook, what do you think were the main reasons for the fall of the Roman Empire? Were the factors that led to the fall of the Roman Empire present from the beginning (during the reign of Julius Caesar) or only due to events near the Empire’s end?”
This essay must be at least 500 words in length and have at least one quote from the textbook to recieve full credit.
Quiz: Some questions are from the Boundless text, some are original. The course Map links to the quiz. | 384 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/herkimerwesterncivilization/chapter/module-overview-5/ | pressbooks | pressbooks-0000.json.gz:88626 | https://library.achievingthedream.org/herkimerwesterncivilization/chapter/module-overview-5/ |
EuIAcVmANOXPDhAX | 2.6.2.7: Publication Formats and the Information Lifecycle | <IP_ADDRESS>: Publication Formats and the Information Lifecycle
Publication Formats and the Information Lifecycle
Movie: Information Cycle
Activity: The Information Lifecycle
A Closer Look at Common Formats
Tip: Evaluating Articles
selected template will load here
This action is not available.
We can also categorize sources by publication format. That’s because of the difference in time and effort sources in each format require for their production.
Sources in particular formats simply cannot exist until there has been enough time for people to create them. The result is that the sources that are created toward the end of the information lifecycle may come to very different conclusions about the event than did those sources created early on.
Sometimes the information presented in the later formats is more valid and reliable that what is in those produced earlier.
A very good example is that conclusions about the Columbine High School shooting in 1999 and the causes of that tragedy reached by books—which took years to complete after the event—were likely to be very different than the conclusions reached by news coverage created early on. For instance, many early reports concluded that the two teens responsible for the shooting had been shunned by their classmates and that it was the pain of their exclusion that had moved them to take revenge. Consequently, many K-12 schools nationwide took steps to try to ensure that all students felt included in their student bodies.
Movie: Information Cycle
This video explains what kinds of information sources about an event can exist at any point in time during and after that event.
An interactive or media element has been excluded from this version of the text. You can view it online here: https://ohiostate.pressbooks.pub/choosingsources/?p=837
View Movie | View Text Version
Books – Usually a substantial amount of information, published at one time and requiring great effort on the part of the author and a publisher.
Magazines/Journals – Published frequently, containing lots of articles related to some general or specific professional research interest; edited.
Newspapers – Each is usually a daily publication of events of social, political and lifestyle interest.
Web sites – Digital items, each consisting of multiple pages produced by someone with technical skills or the ability to pay someone with technical skills.
Articles – Distinct, short, written pieces that might contain photos and are generally timely. Timeliness can mean that it’s something that is of interest to readers at the point of publication or that is something the writer is thinking about or researching at a given point of time.
Tip: Evaluating Articles
Evaluating whether articles are credible enough for your information need is similar to evaluating any other source. There’s more information on evaluating in Evaluating Sources.
Conference Papers – Written form of papers delivered at a professional or research-related conference. Authors are generally practicing professionals or scholars in the field.
Blogs – Frequently updated websites that do not necessarily require extensive technical skills and can be published by virtually anyone for no cost to themselves other than the time they devote to content creation. Usually marked by postings that indicate the date when each was written.
Documentaries – Works, such as a film or television program, presenting political, social, or historical subject matter in a factual and informative manner and often consisting of actual news films or interviews accompanied by narration.
Online Videos – Short videos produced by anybody, with a lot of money or a little money, about anything for the world to see. Common sites for these are YouTube and Vimeo.
Podcasts – Digital audio files, produced by anyone and about anything, that are available for downloading, often by subscription. | 786 | common-pile/libretexts_filtered | https://bio.libretexts.org/Courses/San_Diego_State_University/BT@SDSU/02%3A_Resources_and_Reading_Materials/2.06%3A_Choosing_and_Using_Sources_-_A_Guide_to_Academic_Research_(Lowry)/2.6.02%3A_Types_of_Sources/2.6.2.07%3A_Publication_Formats_and_the_Information_Lifecycle | libretexts | libretexts-0000.json.gz:18170 | https://bio.libretexts.org/Courses/San_Diego_State_University/BT@SDSU/02%3A_Resources_and_Reading_Materials/2.06%3A_Choosing_and_Using_Sources_-_A_Guide_to_Academic_Research_(Lowry)/2.6.02%3A_Types_of_Sources/2.6.2.07%3A_Publication_Formats_and_the_Information_Lifecycle |
zx4BXn0ZVzzYoMg5 | Dr. B. Mure's materia medica : $b or, provings of the principal animal and vegetable poisons of the Brazilian Empire, and their application in the treatment of disease | DR. B. MURE’S
MATERIA MEDICA,
OR
Provings of the principal Animal and Vegetable Poisons
OF THE
BRAZILIAN EMPIRE;
AND THEIR APPLICATION IN THE TREATMENT OF DISEASE.
TRANSLATED FROM THE FRENCH
AND
ARRANGED ACCORDING TO
HAHNEMANN’S METHOD,
BY
CHARLES J. HEMPEL, M.D.
FELLOW AND CORRESPONDING MEMBER OF THE PENNSYLVANIA HOMŒOPATHIC
COLLEGE; HONORARY MEMBER OF THE HAHNEMANN SOCIETY OF
LONDON, &C., &C.
NEW-YORK:
WILLIAM RADDE, No. 322 BROADWAY,
PHILADELPHIA: RADEMACHER & SHEEK.—BOSTON: OTIS CLAPP.—ST.
LOUIS: J. G. WESSELHOEFT.—LONDON: JAMES EPPS,
112 GREAT RUSSELL-STREET, BLOOMSBURY.—MANCHESTER:
H. TURNER, 41 PICCADILLY.
1854.
ENTERED according to Act of Congress, in the year 1853, by
WILLIAM RADDE,
In the Clerk’s Office, of the District Court, for the
Southern District of New-York.
HENRY LUDWIG, Printer,
45 Vesey-street.
TO THE BRAZILIAN PEOPLE.
Though the precious metals hidden in the Brazilian soil, may be never
so abundant; though the splendor of its precious stones, may be never
so brilliant; though the crops which the soil yields to the farmer, may
be never so rich: yet there are, in the Brazilian empire, treasures
of a far, greater importance, and infinitely more necessary to human
happiness. They are the powerful means which this vast country furnishes
for the cure of disease.
Previous to Hahnemann’s discovery, we were ignorant of a positive method
of determining the use of drugs. We knew that they existed, but we did
not know how to use them; and popular experience, more successful than
the wisdom of the School, had alone picked up a few stray fragments from
the rich harvest which had been abandoned for want of the proper means
of gathering. Providence at last permitted Hahnemann and his disciples
to discover the method of applying remedies to diseases in a positive
and efficacious manner. The dominion of mere palliatives is at an
end.—Homœopathy, by attacking the cause of disease, destroys the chronic
miasms, which are transmitted from generation to generation; dries up
the fountain-heads of epidemic and contagious diseases; enables the
infant-body, by a positive hygiene, to resist the deleterious influences
to which it might be exposed in the course of its existence; and, by
preserving human life, which is the most precious capital of nations
and the first element of their greatness, Homœopathy will insure their
prosperity, provided they adopt it without reserve.
We admire the bold hunter who skims the sharp points of the rocks, for
the purpose of snatching the down from the little ones of the eider; the
indefatigable diver, who, by dint of patient toil, succeeds in bringing
up the diamond from the sands of the river, or the pearl from the bosom
of the sea. Should not the people of Brazil sympathise with the patient
and courageous experimenters, who, under the auspices of Hahnemann,
discover a world of wonderful uses in the neglected products of this
country?
The work which we here offer to the Brazilian people, is not a work of
fiction intended to amuse, but a serious work detailing a series of
painful sensations voluntarily endured by a few devoted men, who were
desirous of finding out the therapeutic uses of the poisonous animals
and plants, the pathogenetic symptoms of which will be found described
in this volume. We shall be amply compensated for the patience and
devotedness which the composition of such a work requires, by the
consciousness that it will do its share in diminishing the sufferings of
mankind.
B. MURE, _Rio Janeiro_.
NOTE TO THE READER:—The symptoms in the following work, are arranged in
groups of five; the figures in the text indicate the numerical order of
these groups.—ED.
CROTALUS CASCAVELLA.
We commence the publication of our provings by the symptoms of the
Crotalus Cascavella, not so much on account of the importance of
the symptoms which the poison of this dangerous reptile produces on
the healthy body; but because the unfortunate experiment which was
attempted a few years ago, on a sick person, offers a fair opportunity
of contrasting the hazardous and uncertain results of a merely clinical
experimentation, with the positive advantages of Hahnemann’s method of
proving.
A popular notion,—and the therapeutics of the Old-School was gradually
built up of such notions,—attributed to the poison of the crotalus
cascavella, the power of curing the elephantiasis of the Greeks, a malady
which, in Brazil, goes by the name of _morphea_, or _Lazarus’-evil_.
A disciple of Hahnemann might have verified this belief without any
difficulty, and without endangering human life. But the Old-School who
does not acknowledge our method of proving, had to remain in doubt about
this curative virtue of the cascavella, until a patient and physician
would be found sufficiently bold and logical to apply to a frightful
disease a still more frightful remedy. Mariano José Machado, fell a
victim to his heroic attempt, and, by his death, dissipated the illusory
hopes founded on the curative virtue of the poison of the cascavella.
Now what conclusion shall we draw from this fact? That the practitioner
who advised the attempt, has been imprudent and censureable? God forbid
that we should commit such an act of injustice. A patient has succumbed
to a clinical experiment; let us honor the heroic courage with which he
braved the serpent’s bite; let us honor the zeal of the practitioner,
who persuaded him to risk a few years of a loathsome existence for the
chance, though uncertain, of a cure. The unhappy Machado has been saved a
few years of cruel suffering; but what a joy it would have afforded him
and his miserable fellow-sufferers, if the remedy for their loathsome
disease had been known! what a glory it would have been to the physician
who should have conducted them to the haven of relief![1]
However, a homicide has been committed on this occasion, and though the
perpetrators may be free from blame, yet we may justly condemn the
deceitful science that has to resort to such dangerous practices, in
order to augment its resources and enlarge its boundaries. Like unto the
vile poisoner who, when his poisons fail him, resorts to the stiletto, as
a means of gratifying his cupidity or his ambition, allopathy sacrifices
human life, and, like him, will have an ignominious end. The solemn
homicide, which was committed a few years ago in this capital in the
name of science, may be of use to the world, by hastening the glorious
recognition of the homœopathic healing art, in these distant regions.
If it was permitted as recently as four years ago, when the name of
Hahnemann was scarcely known in this country, to kill a man for the
purpose of trying a drug, we venture to say that, at this period, nobody
would either dare to propose or accept such a murderous practice.
It will be seen, in studying the symptoms which we have obtained from the
poison of the crotalus, that there are very few among them which resemble
the tuberculous lepra, and that this terrible malady will, therefore,
have to be cured by some other means. Fortunately, homœopathy teaches us
the method of discovering a suitable remedy in the place of the crotalus
poison, which we now know has to be abandoned as a remedy for lepra,
and the success which we have already obtained, enables us to indulge
the hope, that the Brazilian lepra, as well as the elephantiasis of the
Arabs, will soon disappear entirely, under the operation of the suitable
dynamised homœopathic agent.
The crotalus will become a useful adjunct to the lachesis proved by
Doctor Hering; it is my belief that it affects the organism longer and
more thoroughly than the latter, and will effect many cures which had to
remain incomplete under the use of lachesis.
The serpent from which this poison has been extracted, was caught in
the province of Ceara. In this operation I was aided by the young
practitioner who alone, four years ago, had protested against the
dangerous experiment which was made in the hospital of the leprous
patients, of which he was at that time chief physician. His noble heart
revolted against the practice of risking human life, for the sake of
a medical doctrine, and, soon after, he imitated the glorious example
which Hahnemann had set him fifty years previous, by abandoning a
lucrative practice, and the direction of two hospitals. Having first
protested against the bite which the reptile was caused to inflict upon
his patient, he now voluntarily exposed his own life for the purpose of
extracting the poison, which was to be suitably attenuated in order to
convert it into a curative agent. Several drops of the poison spirted
on his face, and might have ended his life, if the inner corner of the
eye had been touched as I first feared it was. At this day, when his
suspicions have been abundantly confirmed by the physiological provings,
Dr. J. V. Martins, is one of the firmest adherents of our rising School.
May he live to see the error which he had instinctively rejected,
completely extinguished by the brilliant light of medical truth.
This terrible serpent is found in the province of Ceara, whence it was
brought to Rio Janeiro. This species generally attains a length of from
four to five feet but the animal from which the poison was taken for
our provings, was three feet long. Its oval-triangular head one half of
which is provided with shields, shows a round depression in front of the
eyes, which are covered with a large elliptical shield, serving as a lid.
The body is big, conical, its movements are sluggish; its upper surface
is covered with scales, the dorsal scales being keeled and somewhat
lanceolate, the scales of the tail being quadrangular and smaller. The
belly is provided with one hundred and seventy large transversal plates;
there are twenty-five plates belonging to the tail, the three first of
which are divided in shields. The extremity of the tail is furnished
with seven or eight capsules of the consistence of parchment which,
when agitated, produce a shrill sound. The color of the crotalus is
a yellowish-brown, much lighter under the belly, with twenty-four or
twenty-six regular long rhomboïdal lines on each side of the back. When
irritated and during the excessive heat, the crotalus spreads a very
fetid musk-like odor. The molar teeth which are few in number, but long
and excessively poisonous, are inserted in exceedingly dilatable jaws.
Every body knows that the poison of this reptile acts with a frightful
intensity; and it was not without great danger that Doctors Mure and
Martins succeeded in obtaining a few drops of it, by compressing from the
living animal the gland which secretes it.
FIRST EXPERIMENT.
1. First day: Heavy pain in the back part of the orbit, and at the left
eyebrow.—Second day: Pain under the right orbit and at the forehead,
right side.—Third day: Dry cough with tickling in the throat, at
night.—Fourth day: Headache extending over the forehead and then the
rest of the head. 5. Fifth day: Smell all day like that of the crotalus,
insipid, nauseous, like the odor perceived in a hospital. Sixth day:
Lancinations in various parts of the body.—Seventh day: Contraction with
pressure at the right eyeball which felt as if drawn out.—Eighth day:
Yellowish diarrhœa.—Ninth day: Pain in the middle of the forehead. 10.
Tenth day: Rheumatic pain in the right shoulder.—Eleventh day: Rheumatic
pain in the left wrist.—Twelfth day: Violent cramps in the heel.
SECOND EXPERIMENT.
(The drug is taken at 10 o’clock in the evening.)
_Spitting of black blood._ 15. Prickling all over the body. Starting
during sleep. Sleeplessness. Fright at night, without knowing about
what. 20. Sleep in the morning. The tip of the nose is drawn up as by a
string which is fastened to a central point of the forehead. Tingling in
the throat. Salt taste in the mouth which cannot be removed by drinking
sugar-water. 25. Pulse a little heavy. Small red conical pimples on the
wrist. Painful pulling on the sides of the neck in turning the head.
Feeling of coldness in the stomach, after having eaten. Sensation as if a
peg were sticking in the middle portion of the liver. 30. Aching pain at
the gums, left side. Circular pain round the abdomen, terminating at the
navel. Two lancinations under the right shoulder, as if with a dagger,
arresting the breathing and reverberating in the chest. Sensation as of
a grain of sand in the outer canthi of the eyes. Burning pinching at
the pylorus. 35. Constriction in the thyroid body. Sensation as if the
right lower limb, from the hip to the heel, were shorter; this sensation,
though illusory, causes him to limp. The left eye feels as if drawn
towards the temple. Burning and constriction in the throat.
_Second day_: Pain in the inner head. 40. The feet are cold. The arms are
weak. Contusive feeling at the inner side of the right shoulder-blade.
Painful heaviness in the loins. Appearance of a blue dazzling light
before the eyes. 45. Borborygmi. Painful pressure in the temples. Desire
to vomit. Sensation, below the breasts, of subcutaneous ulceration.
Lancinations in the dorsal spine as from needles. 50. The prover imagines
he hears some one walking behind him. The cranium presses on the brain
on all sides like an iron helmet. Pulling in the pit of the stomach.
Itching on the thighs. Titillating itching in the ears. 55. Swelling
of the right ear. Deafness. Dreams about parties with illuminations;
quarrels, battles. Frontal headache, as if the forehead would split,
with weight above the eyes, especially at night. Pain in the stomach
extending to the navel. 60. Weariness of the arms and lower limbs.
Smarting in the nostrils. _Cutting sensations all round the eyeball as
if cut out with a penknife._ Pain in the left cheek. Sweat and debility
after eating. 65. Greenish spitting in the morning. Sensation in the
head, as if some living being were walking about in a circle. Shocks in
the brain so violent that one is near losing one’s equilibrium. Continual
twitching of the eyebrows, especially the left. Black, bloody froth
around the lips, in the morning. 70. Tongue of a scarlet-red. Jerking in
the fingers. Pain in the elbow as if the bones were pulled. Sensation as
if a thread were rolling in the eye and were pulling the eyeball toward
the temple. Acute pulling in the thigh, with momentary paralysis in the
right pelvic extremity. 75. Acute lancinations in the right temple.
Very thirsty. Belly-ache after drinking. Pressure in the whole abdomen,
in the direction of the navel. The abdomen is exceedingly sensitive.
80. Great desire for food, suddenly passing off at the sight of the
latter. Loathing of meat. Yellow rings around the eyes. Discharge of an
albuminous substance from the rectum, preceded by tenesmus and urging.
Falling of the rectum for ten minutes. 85. Pain in the hollow of the hand.
_Third day._—Pain in the chest which reaches as far as the back.
Sensation as of an opening in the pit of the stomach through which air
passes. Sleeplessness with agitations. Headache as if the forehead would
split. 90. Headache, nosebleed, and excited feeling in consequence of
having been roused from sleep suddenly. Drawing-up of the lower limb from
the hip to the foot, with crampy pain. Leucorrhœa. Small pimples on the
hairy scalp. The toes remain bent. 95. The nails are red. Sensation as
of water in the chest, with efforts to throw it up, and sensation as if
the heart were floating in a liquid. Constant yawning. Itching of the
tongue. Smarting at the tips of the fingers. 100. Sensation as of dust
in the throat. The pimples at first look like flea-bites, after which
they become elevated like little cones and constitute the centres of an
exfoliation less extensive than that caused by the elaps coralinus, with
a little black speck remaining in the middle. Itching in the canthus of
the eye. Acute sensation of burning and redness of the skin which is
perceptibly sunken in at the opening of the right nostril. The prover
imagines he hears some one moan. 105. The thorax and head feel as if
pressed upon by an iron armor. Sensation as of bands round the abdomen.
Pain in the elbows. Pain in the jugular veins when moving the neck.
Abundant discharge of nasal mucus, at night. 110. Foul taste, or taste
as of onions in the mouth until it is rinsed. Burning and prickling at
the tip of the tongue. Swoon which passes off in the open air. Anorexia
all day, and a good deal of appetite in the evening. Pain above the right
breast. 115. The soup falls into the stomach quite suddenly, and lies
there like a stone, with pain in the back. Stitch in the left side when
drawing breath after drinking. Lancinations in the side.
_Fourth day._—Violent lancinations in the uterus while washing one’s-self
with cold water, the lancinations become frightful when using warm water,
with weight at the uterus. Itching under the feet. 120. Formication in
the feet as high up as the ankles. Prickling in the bends of the knees.
Faint feeling at the stomach. While in a clairvoyant state, he speaks to
somebody who does not answer him. 125. Feeling of fright at night. First
the blood is felt rising in the carotid arteries several times; this
is followed by a faint feeling and lastly by a sensation as if a valve
were suddenly opened. Violent blow at the epigastrium. All his limbs
tremble. Chilliness all over which continues even under the bed-cover.
130. Violent ache at the vertex, and sensitiveness of the hairy scalp
to the touch. Extinction of the voice. Great weakness. Depression of
spirits. Suffocative oppression and fear of another paroxysm. 135.
Sensation as if a red-hot iron were sticking in the vertex. The eyelids
feel heavy. Pain in the lower gums as if they had been touched by a
red-hot iron. Excessive weight at the diaphragm. Continual contusive pain
between the two shoulders, and sometimes slow and measured lancinations
when inclining backwards, as if a vertebra had been fractured. 140.
Constrictive pain in the thyroid body as if strung together with a string.
_Fifth day._—Coldness in the back after eating. Drawing from the neck
to the epigastrium. Pain in the right clavicle. Weight on the orbits,
at night. 145. The feet are icy-cold. Headache above the eyes, at ten
o’clock in the morning. Stomach-ache when eating, as if too empty. The
heart feels as if beating from above downwards. Internal pain between the
shoulders. 150. The inner nose is ulcerated. He is pursued all over by
the idea of death, especially when alone. He can only think of death with
great depression of spirits. Ineffectual desire to weep. Lancinations
in the meatus and auditorius. 155. Vermillion-colored metrorrhagia.
Paralysis of the tongue. She stands for ten minutes on the window-sill,
and she is arrested when on the point of precipitating herself out of the
window. She rises suddenly at three o’clock, uttering two shrill cries
and throwing herself forward. The vermillion-colored metrorrhagia with
which she had been affected since the morning, disappears suddenly. 160.
Profuse flow of tears. The hands are cold. The hands tremble. Loss of
memory. Second attack at six o’clock, after which she seats herself in
an arm-chair. 165. Burning forehead. Palpitation of the heart. Weeping.
She plays with her fingers like a child. The suffocative oppression
increases. 170. Magnetic state, she hears nothing, and again sees the
phantom of death, an immense, black, fleshless skeleton; her tears and
mania increase. Vacant stare. Pressive points in the abdomen.
_Sixth day._—Bone-pain and swelling of the left clavicle. Dream about
a horse which is bathed in a pond and gets drowned gradually. 175.
Piteous moaning during sleep. Even while awake one feels as if one were
falling out of bed. Acute pain at the sacro-lumbar articulation. Loss of
consciousness, one hears and sees nothing. Coldness in the back. 180.
Oppression of breathing, as though there were not air enough in the
house. Contraction of the toes. Desire for snow, without desiring either
water or wine. Itching at the epigastrium. Heat in the thighs. 185. She
exclaims several times: he is in the lions’ den, but they will not bite
him. At six o’clock in the evening, another fit of mania. Magnetic state,
during which she does not answer any questions but hears a strange voice
on her left side and behind her; she follows it, and tilts against the
doors which had been closed and which she scratches with her nails. Three
very nearly similar attacks succeed each other, they are occasionally
interrupted by silly laughter and always end with a flood of tears. She
exclaims again: he is in the den, but the lions will not eat him.
_Seventh day._—Fainting from hunger, before eating. 190. Contusive pain
at the occiput. Somnolence the whole morning. Another attack of mental
alienation, she hears voices which she follows, and sheds a flood of
tears. Her head feels heavy, with stupor. The humeral extremity of the
left clavicle continues to swell. 195. Intermittent metrorrhagia twice a
day, and alternating with the paroxysms of mania. Involuntary emission
of urine during sleep. Pain across the umbilical region, with alternate
sensation of spreading out and pinching together. Swelling of the three
last toes of the left foot. Excoriation and pustules on the toes of the
left foot. 200. Suffocative oppression. Pain in the bones, especially
in the joints, at the shoulder-blades, elbows, at the phalanxes of the
fingers, at the knees, hip and under the toe-nails. Pressure at the right
hip as with the blade of a knife. The metrorrhagia ceases. She cannot
bear seeing any one on her right side, without experiencing palpitation
of the heart and a real fatigue from pleasure.
_Eighth day._ 205. Dreams about enormous shaggy spiders walking towards
one and attempting to crawl over one’s person. Pain in the large
psoas-muscle resembling lancinations. Suffocative oppression. A circular
spot between the two breasts which is black at the upper and red at the
lower portion. Hepatic spots of a bright-yellow color, or freckles on the
upper part of the right hands. 210. Small red pimples on the left foot,
like those which appeared on the hand on the second day of the proving.
Obstinate constipation. Lancinations, as if stabbed with a knife, in
the uterus and anus, especially while washing herself with cold water.
Pains in the lower parts of the belly when taking a cold drink. Excessive
sensitiveness of the epigastrium, which does not even allow the pressure
of the clothes. 215. The molar teeth are excessively sensitive and set on
edge. Vomiting after breakfast in consequence of drinking tepid water.
Flushes of heat in the face. Violent itching at the calves. Small red
pimples with a white tip. 220. While drinking cold water, the veins of
the bend of the knee have a deep-black color. Buzzing in the ears while
going down-stairs.
_Ninth day._—Ache, at night, in the upper molares, with inflammation
of the gums. Spitting of blood mixed with thick phlegm. Dreams about
dead persons and phantoms. 225. Loathing of food. Very deaf, after a
month. She feels as though her eyes were falling out. Slight pain under
the lids. Discharge of white mucus from the mouth. 230. Discharge of a
bright-red blood from the nose. The last phalanges feel as if broken. The
tips of the fingers are blue. The nails are bare. Yellow complexion. 235.
Pain in the left side. She feels uncomfortable in consequence of having
her courses, and is out of humor on account of having them. Aversion
to talking; sensitive mood. Desire to move about. 240. She answers all
questions with: no. Small red pimples all over. Tightness of the head,
from above. Cramps in the arms, as if the nerves had been tied up in a
knot during a venesection.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MORAL AND MENTAL SPHERE: 1. She answers no, whenever she is asked a
question. Sensitive mood. Aversion to talking. Sensation as if one were
falling out of bed, even while awake. 5. Loss of consciousness. She
exclaims: he is in the lions’ den, but they will not bite him. Magnetic
state; she hears a strange voice, follows it and tilts against the doors;
she has three such attacks, occasionally interrupted by laughter and
tears. Ineffectual desire to weep. Loss of memory. 10. Magnetic state;
she hears nothing, and sees a black skeleton. Mania. He thinks he will
die, especially when alone. Depression of spirits. Despair. 15. Anguish.
HEAD: Sensation as of a red-hot iron in the vertex. Lancinations in right
temple. Violent ache at the vertex. Burning forehead. 20. Contusive pain
at the occiput. Tightness of the head, from above. Her head feels heavy,
with stupor. Sensation in the head as if some thing alive were walking
about in a circle. Shocks in the brain. 25. Painful pressure in the
temples. Sensation as if the brain were pressed upon by an iron helmet.
Headache as if the forehead would split, with weight above the eyes.
Pain in middle of forehead. Pain in the interior of the head. 30. Pain
under the right orbit and in right side of forehead. Frontal headache,
afterwards all over the head. Sensitiveness of the having scalp.
EYES: Pain under the lids. Sensation as though her eyes would fall out.
35. Profuse lachrymation. Heavy pain at back part of orbit and left
eyebrow. Vacant stare. Weight on the orbits, at night. The eyelids feel
heavy. 40. Itching of the canthus. Yellow rings round the eyes. Blue
dazzling light before the eyes. Twitching of the eyebrows. Sensation as
if the eyeball were pulled towards the temple by a thread. 45. Sense of a
grain of sand in the outer canthi. The left eye feels as if drawn towards
the temples. Contractive pressure at right eyeball, which felt as if
drawn out. Cutting round the eyeball.
EARS: Buzzing in the ears while going down-stairs. 50. Lancinations in
the meatus auditorius. He imagines he hears some one walking behind him.
Sensation as if some one were moaning. Titillating itching in the ears.
Deafness. 55. Swelling of the right ear.
FACE: Yellow complexion. Alteration of the features. Formication in the
face. Flushes of heat in the face. Pain in left cheek.
NOSE: 60. Ulceration of the inner nose. Discharge of a bloody liquid from
the nose. Sense of burning and redness of the skin, with depression, at
the orifice of the right nostril. Nosebleed. Smarting in the nostrils.
65. Insipid, nauseous smell all day, as in a hospital. The tip of the
nose is drawn up.
TEETH: Pain in lower gums as from a red-hot iron. Aching in the upper
molares, at night, with inflammation of the gums. The molar teeth are
sensitive and set on edge. 70. Aching pain in left gums.
MOUTH: Paralysis of the tongue. Burning and prickling at the tip of the
tongue. Itching of the tongue. Tongue of a scarlet-red. 75. Pain in the
tongue. Spitting of black blood. Spitting of blood, mixed with thick
phlegm. Discharge of white mucus from the mouth. Greenish spitting in the
morning. 80. Black, bloody froth around the lips in the morning. Thick,
viscid saliva which it is difficult to get out.
TASTE AND GASTRIC SYMPTOMS: Salt taste in the mouth, not removed by
drinking sugar-water. Taste as of onions in the mouth, before rinsing
it. Aversion to food. 85. Desire for snow. Desire for food, passing off
on seeing it. Thirst. Fainting from hunger. Coldness in the back after
eating. 90. Anorexia all day. The soup descends into the stomach quite
suddenly, and lies there like a heavy body, with pain in the back.
Stitch in the left side, after drinking when drawing breath. Colic after
drinking. Aversion to meat. 95. Sweat and debility after eating. Desire
to vomit.
THROAT: Constriction of the throat. Sensation of a lump in his throat.
Difficulty of swallowing. 100. Sense of dust in the throat. Burning and
constriction in the throat. Tingling in the throat.
STOMACH: Stomach-ache, when eating, as if too empty. Faint feeling at the
stomach. 105. Pulling in pit of stomach. Sensation of an opening in pit
of stomach, through which air passes. Pain from stomach to navel. Burning
pinching at the pylorus. Feeling of coldness in the stomach, after eating.
ABDOMEN: 110. Sensitiveness of the epigastrium. Pressive points in the
abdomen. Lancing pains in the large psoas-muscle. Pains in lower part of
belly when taking a cold drink. Pain across the umbilical region, with
alternate sensation of spreading out and pinching together. 115. Itching
at the epigastrium. Shock at the epigastrium. Falling of the rectum.
Weight at the diaphragm. Sense of bands round the abdomen. 120. Pressure
in abdomen, towards the navel. The abdomen is sensitive. Discharge of an
albuminous substance from the rectum, preceded by tenesmus. Borborygmi.
Sense of a peg sticking in the middle of the liver. 125. Circular pain
round the abdomen, terminating at the navel.
STOOL: Constipation. Yellowish diarrhœa.
URINARY AND SEXUAL ORGANS: Emission of a deeply-colored urine.
Metrorrhagia (vermillion-colored). 130. Feels uncomfortable in
consequence of having her courses. Metrorrhagia alternating with mania.
Lancination in uterus, especially when washing one’s self with warm
water, with weight at the uterus. Leucorrhœa.
BRONCHIAL SYMPTOMS: Aphonia. 135. Pain in the larynx. Dry cough, with
tickling in the throat, at night.
CHEST: Round spot between the breasts, black above and red below.
Swelling of the humeral extremity of the left clavicle. Palpitation of
the heart. 140. Suffocative oppression. Oppression of breathing, as
from want of air. Bone pain and swelling of the left clavicle. Anxious
breathing. The heart feels as if beating from above downwards. 145. The
thorax feels as if encased in iron. Pain in the right clavicle. Violent
pains in the chest. Pain above the right breast. Sensation of water in
the chest, and as if the heart were floating in a liquid. 150. Copious
sweat on the chest. Ulcerative feeling under the breast.
BACK: Coldness in the back. Slow lancinations between the shoulders,
when inclining backwards. Acute pain at the sacro-lumbar articulation.
155. Internal pain between the shoulders. Contusive pain between the
shoulders. Lancination in the dorsal spine, as from needles. Painful
heaviness in the loins. Contusive feeling at inner side of right
shoulder-blade.
NECK: 160. Constrictive pain in thyroid body. Swelling of the jugular
veins. He feels the blood rise in the carotid arteries, followed by faint
feeling and sensation as if a valve were opening. Drawing from the neck
to the epigastrium. Pain in the jugular veins when moving, the neck. 165.
Constriction in thyroid body. Painful pulling in the sides of the neck
when turning the head.
UPPER EXTREMITIES: Lancinations under the right shoulder arresting
the breathing. The bitten hand and arm are inflamed and very painful.
Sensation of swelling in the forearm. Violent pain in the whole arm.
Weakness of the arms. 170. Cramps in the arms as if the nerves had
been tied up in a knot, during a venesection. Rheumatic pain in right
shoulder. Trembling of the hands. Slight pain in the hollow of the hand.
Pulling pain in the elbows. 175. Pain in the elbows. Enormous swelling
of the hand. Feeling of coldness in the hand. Jerking in the fingers.
Smarting of the tips of the fingers. 180. The tips of the fingers are
blue. The last phalanges feel as if broken. She plays with her fingers.
Nails are red. The nails are bare. 185. Rheumatic pain in left wrist.
LOWER EXTREMITIES: Sensation as if the whole right lower limb were
shorter; this causes him to limp. Acute pulling in the thigh, with
momentary paralysis. Itching on the thighs. Drawing-up of the lower
limb, with crampy pain. 190. Pressure at right hip as from a knife. Heat
in the thighs. Sense of burning heat in the legs. Prickling in the bends
of the knees. Itching of the calves. 195. Cold feet. Sense of coldness in
the feet. The feet are icy-cold. Itching under the feet. Formication in
the feet. 200. The toes remain bent. Contraction of the toes. Swelling of
the three last toes of the left foot. Violent cramp of the heel.
SLEEP: Sudden rising at three in the morning, and uttering two shrill
cries, with throwing herself forward. 205. Dreams about dead persons and
phantoms. Dreams about spiders attempting to crawl over her. Disposition
to slumber. Somnolence, the whole morning. Moaning during sleep. 210.
Involuntary urination during sleep. Dream about a horse which is drowned
in a pond. Yawning. Dreams about illuminations, quarrels. Sleeplessness.
215. Starting during sleep. Fright at night, without knowing about what.
FEVER: Chilliness all over. Sense of chilliness. Pulse heavy. 220. Pulse
98 to 104.
CUTANEOUS SYMPTOMS: Bright-yellow spots on upper part of right hand.
Red pimples on left foot. Red pimples all over. Red pimples with white
tips. 225. Pustules on the left toes. Pimples on the hairy scalp. Pimples
resembling flea-bites, afterwards becoming raised and exfoliating,
leaving a black point in the centre. Red pimples on the wrist.
GENERAL SYMPTOMS: Pain in left side. 230. Trembling of the whole body.
She cannot see any one on her right side without feeling a palpitation of
the heart, and a real fatigue from pleasure. Desire to move about. Pain
in the joints, shoulder-blades, elbows, &c. Trembling of the limbs. 235.
Weakness. Torpor. Pains in the whole body, inducing a moaning. Swoon.
Lancinations in the side. 240. Prickling all over. Weariness of the arms
and lower limbs. Lancinations in various parts of the body.
ELAPS CORALLINUS.
ELAPS. ELAPS VENUSTISSIMUS (SPIX.) VIPERA CORALLINA.
The elaps corallinus is found quite frequently in the woods all along
the coast of Brazil, and its bite is much dreaded. Its colors are more
brilliant and more agreeably combined than those of any other serpent
in Brazil. Its head is small, covered with large polygonal scales; it
swells behind and is continuous with the neck from which it is scarcely
distinguished as regards size. It has round and small eyes; the jaws
which are little dilatable, are furnished with sharp teeth accompanied
by fangs that rest on the venomous glands. The body is about two
feet and a half in length; it is round, rather big in proportion to
the head, and terminates in a sharp tail. The upper part is covered
with smooth rhomboïdal scales; the belly is covered with two hundred
transverse shields; the tail numbers fifty shields, which are disposed
in two parallel rows. Its colors are disposed in the shape of rings of
a vermillion-red, alternating with black rings, each two rings being
separated by circular lines of a greenish white. The upper part of the
head is black; likewise the first colored ring of the neck; the shields
of the jaws are white, and are separated from each other by black lines.
As in the case of the crotalus cascavella, the poison was taken from the
living reptile, not without danger.
As soon as I had determined to institute provings with the poison of
the cobra-coral, several of these reptiles were, at my request, brought
to me on the same day, so frequent are they in the forests of Sahy. The
animal which I selected was wrapt up in a piece of linen-cloth, and,
after its head had been steadied with a little wooden pin, some eight or
ten drops of poison were pressed out of its jaws by means of a pair of
steel-pincers, which I received on one hundred grains of sugar of milk,
and at once subjected to the process of trituration in my mechanical
mortar. They received six thousand successive turns. One grain of this
mass was triturated a second time, and a grain of this second trituration
a third time, each receiving three thousand turns.
Even while triturating the drug in my mortar, the most striking
effects were produced by the simple emanations ascending from it. This
phenomenon, however, is observed whenever I cause a somewhat active drug
to be triturated in the mortar.
The symptoms which I have collected, are not a great many, but they
can be depended upon. Most of the symptoms were experienced by several
provers, and some of them have already been confirmed by treatment, among
which may be mentioned the oppression in going up-stairs, the vesicular
eruption on the feet and the deafness. This last symptom is of great
importance on account of its being so obstinate. For pulmonary affections
the poison of the cobral may likewise prove a valuable remedy, especially
for the second stage of phthisis, characterised by bloody cough and
derangement of the digestive functions. It may likewise be serviceable in
mental alienation and cutaneous eruptions.
The special action which this poison seems to exercise on the right side,
the paralysis, the lancinations, have appeared to me worthy of attention.
The gyratory motions, the desire to move to and fro, the scaling off of
the epidermis and several symptoms relating to the disposition and the
mind, seem to deserve the attention of the philosophical physician.
There certainly exist remarkable analogies between the symptoms of
the cobral and those of the lachesis. The differences, however, are
sufficiently numerous to refute the doctrine that all serpent-poisons
act almost alike and that the cobral, for instance, may be resorted to
as a perfect succedaneum of the lachesis. I am convinced of the contrary
to such an extent that it is my belief that the poison of serpents alone
would, if sufficiently proved, furnish the safest and most rapid means of
combating all human infirmities. Every epoch in the history of the world
is undoubtedly possessed of therapeutic means which are more particularly
homœopathic to the general character of the ruling maladies. Hence it
is probable that when the human species shall have been freed from the
miasms which now undermine its vitality, the simple flowers on the fields
will be sufficient to control the remaining indispositions. Whereas we,
unfortunate heirs of the chronic miasms of all ages, lepra, scrofula,
syphilis and a host of other subtle plagues, are compelled to employ the
most frightful agents in order to meet the intensity of our diseases.
_First to third day._—1. Reveries in the day-time, one imagines one is
receiving blows. One imagines one hears some one speak. One hears talking
without comprehending. Absence of mind. 5. Nightmare and congestion about
the head. Anxious dreams. Weight in the right parietal region and pain
which penetrates to the nape of the neck. Beating at regular intervals
in the nape of the neck, like the ticking of a clock. Weight in the
forehead and above the orbits. 10. Boring pain from the vertex to the
right eyebrow. Pain on the right side, which seems to be seated in the
cerebellum. Sweat on the forehead and nape of the neck. The head falls
forward with violence. Painful constriction in the temples and eyes. 15.
Violent throbbing of the external carotid. Horrid pains when inclining
the head backwards; less when inclining it forwards. Tension in the nape
of the neck. Stiffness which prevents the head being turned. Sensation
as of a foreign body in the right temple. 20. Lancinations in the outer
angle of the left eye. Boring pain from the lower jaw to the right eye,
and then from the right eyelid to the ear. Desire to close one’s eyes
as in fever. Sharp pricking in the inner canthi of the eyes. Aching
pains around the eyes, with vanishing of sight. 25. Continual buzzing
as from a fly in the meatus auditorius. _Constant deafness._ Ringing in
the ears. Discharge of a serous fluid from the left ear. Distressing
prickling in the superior nasal fossa. 30. Swelling of the gums on the
last three molar teeth. Prickling as if caused by strong spice, after
having triturated the drug. Prickling at the tip of the tongue. Sour
eructations, desire for cold water, ice. Loathing of food, acidity after
every mouthful of food. 35. Pressive constriction in the throat. Burning
from the larynx to the tongue as from peppermint, with desire for fresh
air. The food descends in the œsophagus as if turned round like a screw.
At other times the soup falls heavily and precipitately, as if through
a metallic tube into the stomach, which trembles violently. Watery,
yellowish diarrhœa, which is mixed with slime, attended with rumbling in
the bowels. 40. Urine almost red. Urine profuse. Urine red. Constriction
of the sphincter. Continual discharge of prostatic fluid. 45. Thickening
of the skin of the prepuce, with inflammation. Excoriation on the back
of the penis, which causes a continual itching. Weakness of the genital
powers, impotence. Lancinations and prickings in the penis. Weight and
swelling of the testicles. 50. Spitting of black coagula of blood, with
painful tearing as if proceeding from the heart. Almost constant cough.
Sensation in the chest and at the sternum as if the pleuræ would be
torn off, and as if the two lungs would be separated from each other by
force. Inability to incline to the right side, in consequence of a very
painful pulling in the right lung. Violent itching, drawing, pricking
at the epigastrium, which hinders drawing a full breath. 55. A chronic
loss of breath when going up-stairs, disappears after the second day
of the proving. Violent fit of dry cough which finally ends in raising
black blood, with frightful tearing pains in every part of the lungs,
and especially in the right side, at the upper part of the chest. Taste
of blood in the mouth previous to the paroxysm of cough, succeeded by a
desire to vomit. Burning in the hands while preparing the drug. Prickling
in the back of the right hand. 60. Pulling in the right hand, which
extends to the ring-finger. Pains in the elbows. Crampy constriction
in the phalanxes of the fingers and under the nails. Lancinations and
prickling in the back of the hand. The blood remains congested in the
hand, which is of a violet color and as if paralysed; it has to be kept
erect in order to prevent the congestion. 65. A black blood spirts out
of the finger when pricking it ever so little. Vesicular eruption on the
feet. Pains in the knees. Pains in the knees as if bruised and contused,
especially in the left knee, which does not bear contact, and where the
pain is as keen as if the part had been sprained.
_Third to sixth day._—Sensitiveness _of the right side_. 70. Inability
to rise in the morning in consequence of the pain in the right side.
Slight phlyctænæ make their appearance here and there, especially on
the extremities; the epidermis surrounding them sometimes scales off.
Drowsy the whole day, but sleepless nights. Dreaming about the business
of the day. Pain in the forehead. 75. Red eyebrows. The eye is extremely
sensitive to cold water. Stoppage of the right nostril, improved by
resting on the same side. Bad smell from the nose. Pulling in the
œsophagus. 80. Violent headache, if the desire for food is not satisfied
on the instant. Suffocative oppression after eating. Bloating of the
stomach after eating. Pulling in the pit of the stomach. Violent hunger.
85. Pressure at the right hypochondrium. Pressure in the left side, which
extends to the vertebral column. Dull pain in the right lung, worse when
walking. Congestion of blood to the throat, which is caused by the pain
in the lung. Sense of spraining and stiffness in the knee joint.
_Seventh day._—90. Painful pressure at the nape of the neck, as if the
cerebellum had settled downwards. Eyes red and inflamed. Blood oozes from
the eyes. Glassy look. Bitter, salt taste in the mouth. 95. Noisy and
violent borborygmi. Stitch in the side. Falling of the rectum. Hoarse
voice. Violent beating of the heart. 100. Pain as if bruised in the
sides of the neck. Painful drawing at the inner side of the arm, from
the axilla to the wrist, but felt especially at the bend of the elbow.
The right hand feels as if paralysed. Shuddering from the hand to the
shoulder when dipping the former into cold water. A good deal of distress
in the whole abdomen. 105. The left foot is swollen and blue, with red
spots. Drawing-up of the feet. Twitching in the parotid gland. The saliva
tastes salt. Crusty eruption over the ear and a part of the cheek. 110.
Itching in the ear, in the evening. Red urine, with cloudy sediment.
Pinching sensation at the helix and lobe of the ear. Discharge of a
greenish-yellow liquid from the ear, in the morning. Painfulness of the
parotid gland. 115. Itching pimple on the legs. Discharge of blood from
the ear. Swelling of the inguinal gland. The left groin is painful to
contact. Colic with urging to stool. 120. Blackish and frothy diarrhœa.
The urine is very thick and deposits a red sediment.
SECOND EXPERIMENT.
_First day._—Tension in the nape of the neck and inability to turn the
head. Dark, almost red complexion. Pain in the urethra while urinating.
125. Pricking in the left gums. Desire for food, with aversion to
eating. Lassitude in the limbs. Prickling under the toe-nails. Sense of
excoriation at the nape of neck. 130. Violent pains in the lumbar region,
like a band extending to the uterus. Weight at the uterus. Weight at the
stomach after eating. Acidity, nausea and faint feeling. Weight at the
left side of the uterus. 135. Unquenchable thirst. Feeling of coldness
in the chest after drinking. The lower limbs give way. Pain in the
right instep as after a forced journey. Colic gradually spreading all
through the colon, from the cœcum to the rectum. 140. Sleeplessness with
uneasiness. Weight at the vagina, in consequence of an attack of hysteric
colic. After a continued congestion of the blood to the thoracic
viscera, it seems to rush to the viscera of the abdomen. Prickling in
the uterus, vagina and pubic region, extending to the epigastrium, with
painful lancinations. Lancinations at the umbilicus from above downward,
extending to the womb. 145. Vomiting of green bile, followed by bilious
diarrhœa. Buzzing in the ear. In cleaning the meatus auditorius, small
balls of hardened and black wax are taken from it.
_Second day._—Dull pain in the right lung, worse while walking, with
distress and rush of blood to the throat. Prickling and pulling in the
right lung. 150. Blear-eyedness. Constriction of the thorax as by a
corset. Pressure under the right arm. White, albuminous leucorrhœa.
Sensation as of sand in the eyes. 155. Discharge of white and watery
mucus from the nose. Constant tickling at the nose. Great weight at the
uterus when rising, worse during a walk. Coryza when exposed to the least
current of air; sneezing. Acute contusive pain at the inner side of the
left leg, and sensation as if something were rising and descending in
the tibia. 160. Difficulty of opening the eyes. Sensation as if long and
white filaments were floating before the eyes. In closing the eyes, every
thing looks red, dotted with black points. Itching in the right meatus
auditorius. Stoppage in the œsophagus, after eating, as if a sponge had
lodged there. 165. The beverage is arrested in the œsophagus as by a
spasmodic contraction of this organ, after which it falls heavily into
the stomach. Lancinations from above downward in the posterior muscles
of the trunk, from the occiput to the sacrum, attended with pains in
the temples. Lancinations in the soles of the feet, while seated; they
disappear by walking. Pains in the forehead. Discharge of black blood,
between the menstrual periods. 170. In the morning the hairy scalp, at
the occipital protuberance, feels as if raw. Violent itching in the
vagina. Prickling as with thousands of pins. Aching pain in the left
side. Cramps in the calves, worse in the afternoon.
_Third day._—175. Breakfast agrees pretty well, but the dinner distresses
him. Very sensitive to the cold. Warmth in the hollow of the hand,
after dinner. Coldness in the back. Blear-eyed. 180. Sensation, in the
right eye, of a gauze having a bluish-white or mother-of-pearl color.
Sense of stiffness and spraining in the knee-joint. Disposition to
faint. Sleeplessness or else drowsiness, with distressing dreams about
the business of the day. 185. Lancinations in the vagina. Heat in the
left nostril, and swelling of the nasal septum. Weight in the vagina, on
the left side, and acute pain which prevents her from going up-stairs.
Sensations in the abdomen as of a tube which can suddenly be closed by
means of a valve, and through which a column of some liquid is poured
into the abdomen, where a violent rumbling takes place. The left eyebrow
is painful and drawn down. 190. Eructation tasting like spoiled eggs in
the throat. Lancinations which proceed simultaneously from the groins and
cross each other at the symphysis pubis. Violent diarrhœa, consisting of
sanguinolent mucus and yellow bile, whereas it had been green heretofore.
Sensation, while walking, of a black disk of four inches in diameter,
at the distance of a few paces from the eye. Discharge of black blood
with stool, with acute colic as though the intestines would be twisted
together. 195. Stye at the left eye, with violent lancination. Tickling
and reddish streaks of the sclerotica. Red spot on the knee-pan. Violent
colic as though the intestines would become twisted amongst each other.
Bloody dysentery, followed by sleep. 200. The menses appear before their
regular period. Pressure between the shoulders. Greyish gauze before
the eyes, like a cloud, which becomes thicker; at first it is of the
size of a penny, and spreads until finally it covers the whole field
of vision. Sensation as if an iron bar were pressing on the loins.
Lancination in the stye on the left eye. 205. Lancinations in the dorsal
muscles, especially in raising the arms. The right side is numb and as if
paralysed, from the shoulder to the knee. Pulling at the cardiac orifice,
with sensation of hunger and boring feeling extending to the vertebral
column. Pain in the spinal marrow, from the nape of the neck to the
sacro-lumbar articulation. The neck remains twisted when turning it,
with constriction in the thyroid gland. Crampy constriction at the bend
of the elbow, especially when moving it. 210. Weight in the stomach after
the introduction of food; it turns, with desire to vomit. Constrictive
pain at the bend of the elbow and knee. Itching in the meatus auditorius.
This itching spreads in the interior of the cheek all along the duct of
steno. Watery saliva. 215. The viscous saliva is more abundant. Changing
one’s position is painful, one would like to remain seated or lying.
Diarrhœa consisting of undigested food. The teeth are loose; one is
unable to chew bread. Loose cough.
_Fourth day._—220. Complete paralysis of the right side, with inability
to rise in the morning. Violent itching in the left eye. Complete
blindness for five minutes. The right hand is benumbed; a stitch is felt
through the thickness of the metacarpus. Smarting under the nails. 225.
Painful drawing at the inner part of the arm, from the axilla to the
wrist; but especially distressing at the spot where the prover had been
bled. Small red tetter at the corner of the right nostril, spreading
to the cheek, with tickling. Stoppage of the nostrils, one has to
breathe by the mouth. Suffocative oppression while eating. 230. Violent
distress throughout the thoracic viscera. Cyanosis and reddish spots of
the extremities. Violent itching under the axilla, and appearance of a
tetter. The blood rushes to the right hand, which is of a violet color
and as if paralysed. Shuddering up to the shoulder when dipping the
hand in water. 235. The arm and hand are swollen, blueish, and covered
with red spots, likewise the right leg and foot. Cramps in the whole of
the right side. Cramps in the calves. Swelling of the stomach. Acute
lancinations, from time to time, in the fourth toe of the left foot, as
if pierced by a needle. 240. Quick and transitory lancinations in the
back, sides and arms. Pain at the roots of the hairs on the occiput.
Fruit and cold drinks lie in the stomach like ice. Sudden colic, with
diarrhœa. Lancinations and stitches in the upper part of each lung.
245. Bloat in the region of the diaphragm. After taking a cold drink,
shuddering from the head to the feet, and chattering of the teeth.
Lancinations in the inner side of the knee. Lancinations from the root of
the nose to the ear. Sensitiveness in the pit of the stomach. 250. The
tips of the fingers peel off, which is painful. Redness and pain under
the nails, the parts look as if raw. Biting one’s hand during sleep,
without waking. Pressure between the shoulders. Liquids descend in the
œsophagus with a sound like glou-glou. 255. The nose continues to swell
and the pain extends to the ear. Prickling in the eyebrows, especially
the left. Acute pain in the iliac bone, on the right side, as though the
crest were swollen and the periosteum inflamed. The right leg up to the
knee is cold as ice. Frontal headache. 260. Discharge of black, liquid
blood from the bowels. Borborygmi and noisy flatulence. Constriction of
the sphincter, a quarter of an hour after the discharge. The peristaltic
motion of the intestines takes place from below upwards; the blood
seems to flow backwards in the abdomen, with violent pain and frightful
palpitations, succeeded by lancinations which prevent walking.
_Fifth day._—Dreams about dead persons; she kisses dead persons, falls
into pits where her feet get entangled; she walks sideways. 265.
Quarrelsome, irritable mood, with agitation of the mind. Good appetite.
The heel begins to peel off the same as the fingers. While dreaming she
bites her forearm. Vertigo so as to fall forwards. 270. Sensation as
if falling forward, though the prover remains immoveable. When raising
the hand to the right side of the nape of the neck, a penetrating pain
is felt which spreads to the ear. Stitch in the side, a whole day. The
breathing through the nose is interrupted. One hears some one talking.
275. Violent itching of the hairy scalp.
_Sixth day._—Strange illusion of hearing; she heard whistling and
ringing, and rises to see where it is. Frightful dreams; she buries a
dead person and, with a knife, digs about in his wounds. Afterwards the
experiences a burning remorse and sheds a flood of tears. She dreams
that she has a fight with a man condemned to the galleys. 280. Desire to
strike and pick a quarrel. Mental excitements. Itching of the soles of
the feet, which continue to peel off. Small pimple with a good deal of
itching. Slight discharge of a clear mucus from the urethra. 285. At the
least contrariety the body shudders and the blood boils, with pricklings.
Lassitude in all the limbs.
_Seventh day._—Desire to go to the country and play about in the
grass. Desire to be alone; for days she remains in the corner of the
anti-chamber. Sound sleep. Plans about travelling, &c. 290. She hears
distant whistling. Bread tastes flat, like the triturated poison which
had been swallowed for the purpose of proving it. She wants to leave the
house at the moment when she is going to bed. She retires to a distant
room to work. Irresistible desire to cry out with all her might. 295.
Loathing of meat, bananas, and particularly bread. Desire for oranges,
acids, and especially for sour beef. Profuse cold sweat all over the body.
_Eighth day._—During a whole month, bread does not mix up with other
food, it returns by the nose the whole day, whereas the other kinds of
food are either digested naturally or thrown up again by the mouth.
Metrorrhagia. 300. Violent aversion to light; one prefers to be in the
dark. Violent diarrhœa, continued. Breaking out of little pimples with an
oval base, they dry up and are followed by desquamation of the epidermis.
_Ninth day._—Complete loss of appetite, she eats nothing but oranges.
Bruising pain in the upper portion of the deltoid muscle, as if she
had received a violent blow on the shoulder. 305. Tongue black or of a
dark-red color. The tetter at the wing of the nose peels off. Yellow,
irregular spots on the hand and around the fingers, over a considerable
space. A red, transversal bar of an inch in thickness is seen in opening
the eyes, and a red disk when shutting them. Boils on the arm. 310.
Profound ennui. Depression of spirits; desire to be in a deep cavern,
where nobody can be seen. Absence of thought. Complete loss of one’s
self, so that the time passes away without one being conscious of it in
the least.
_Tenth day._—After eating an orange and bread, the orange returns by the
mouth and the bread by the nose. 315. Coldness at the back part of the
thighs. Furfuraceous tetter and itching at the hairy scalp. She feels
hungry and yet is unable to eat. Small miliary pimples upon a red base
at the corner of the nose. Violent hunger. 320. Burning in the stomach
which extends to the duodenum. Suffocative oppression after eating. Pain
in the right side, as if in the pleura, striking to the axilla. Constant
hunger which cannot be appeased on account of the continual vomiting.
Small suppurating pimples on the hands, fingers, wrists, gums, at the
inside of the cheeks. 325. Violent itching at the abdomen, especially
while walking. Innumerable white pimples at the inside of the thighs,
which get inflamed in the day-time and prevent one from walking in the
evening. Burning of the eyebrows. Drowsy in the day-time, especially at
two o’clock, and sleepless at night. Tickling at the root of the nose,
as from worms. 330. Tongue swollen and whitish, in the morning. Bloating
around the eyes which appear sunken in the morning. The arterial blood
spirts from the nose and ears. Formication at the anus as if a worm were
gnawing at the parts. Suppression of urine. 335. Tickling and frightful
formication at the vulva. Very thirsty; desire for milk. Cold sweat all
over. Slow digestion, one has to drink after every mouthful that one
swallows. Excessive horror of rain. 340. Discharge of a black blood from
the womb. Noise as from a valve closing in the trachea and causing a
column of air to ascend to the pharynx.
_Eleventh day._—Discharge of blood from the ear. The bread returns by the
nose.
_Twelfth day._—Loathing of bread and other food. 345. Decided taste for
oranges and salad. Watery vomiting in the morning. Ellyptical pimples
full of serum. Acute pains in the descending colon. Small red pimples at
the tips of the fingers.
_Thirteenth day._—350. The gums become loose near to the roots of the
teeth. The intestines seem to turn violently about one other, after which
they feel for a few moments as if twisted together like a cord, and then
are suddenly strung together as by a knot, causing a sensation as if the
abdomen would be choked from side to side. Extreme sensation of coldness
after drinking and as if ice-water were rising and descending through a
cylindrical opening in the left lungs. Vomiting of food.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL AND MORAL: 1. He imagines he is receiving blows. Absence of mind.
Horror of rain. Complete forgetfulness of one’s-self. 5. She wants to go
out at the moment of retiring to bed. Irresistible desire to cry out.
Vertigo, she falls forwards. Depression of spirits, she desires to be
in a cavern, alone. Desire for country-air and sport. 10. Desire for
solitude. Plans about travelling, &c. Quarrelsome.
HEAD: Pain in cerebellum, right side. The hairy scalp at the occipital
protuberance feels raw, in the morning. 15. Painful constriction in the
temples and eyes. Horrid pains when inclining the head backwards. Weight
in forehead. Weight in right parietal region and pain penetrating to the
nape of the neck. Sensation as of a foreign body in right temple. 20.
Pain in the forehead. Boring pain from vertex to right eyebrow. Pain at
the roots of the hairs on the occiput. Itching of the hairy scalp.
FACE: Dark complexion. 25. Itching in the ear and cheek. Lancinations
from the root of the nose to the ear. Boring pain from the lower jaw to
the right eye, and then from the right eyelid to the ear.
EAR: Pinching at helix and lobule. Itching in the ear. 30. The cerumen is
hardened and black. Itching in the right meatus. Deafness. Illusion of
hearing, she hears a whistling and ringing. He imagines he hears some one
speak. 35. Ringing. Constant buzzing in the meatus. Buzzing. Discharge of
a serous fluid from the left ear. Discharge of blood from the ear. 40.
Discharge of a greenish-yellow liquid from the ear, morning.
EYES: Stye at left eye, with lancination. Tickling and red streaks of
the sclerotica. The left eyebrow is painful and drawn down. Blood
oozes from the eyes. 45. Blindness for some minutes. Violent itching
in the left eye. Prickling in the eyebrows. Aversion to light. Burning
of the eyebrows. 50. Bloating around the eyes, in the morning. Aching
pain around the eyes, with vanishing of sight. Sharp prickling in the
inner canthi. Desire to close one’s eyes. Lancination in outer canthus
of left eye. 55. The eye is sensitive to cold water. Red eyebrows. Eyes
red and inflamed. Difficulty of opening the eyes. Sand in the eyes. 60.
Blear-eyed. Glassy look. Sensation in the right eye as of a gauze of a
blueish-white or mother-of-pearl color. Black disk at a few feet from the
eye, when walking. Greyish gauze before the eyes, gradually spreading
over the whole field of vision. 65. Red bar before the eyes when opening
them, and a red disk when shutting them. When closing the eyes, every
thing looks red, dotted with black points. Sense of long, white filaments
before the eyes.
NOSE: Tickling at the nose. Stoppage of right nostril. 70. Bad smell from
the nose. Distressing prickling in the superior nasal fossa. Tickling at
the root of the nose. Swelling of the nose, with pain extending to the
ear. Stoppage of the nostrils. 75. Heat in left nostril, and swelling of
the septum. White and watery mucus is discharged from the nose.
TEETH: The teeth are loose. Prickling in left gums. Swelling of the gums
on the last three molares. 80. Looseness of the gums at the roots of the
teeth.
MOUTH: Salt tasting saliva. Bitter, salt taste in mouth. Prickling at the
tip of the tongue. Tongue swollen and whitish, in the morning. 85. Tongue
black or dark-red.
THROAT: The beverage is arrested in the œsophagus as by a spasmodic
contraction of this organ, after which it descends like a heavy weight.
Pulling in the œsophagus. Constriction with pressure, in the throat.
Sensation as if the food turned like a screw while passing down. 90.
Burning as from peppermint, from the larynx to the tongue. Sensation
as of a valve in the trachea causing a column of air to ascend in the
pharynx. Stoppage in the œsophagus, after eating, as if a sponge had
lodged there.
GASTRIC SYMPTOMS: Vomiting of green bile, followed by bilious diarrhœa.
Weight at the stomach, after eating. 95. Acidity, with nausea and faint
feeling. Violent thirst. Cold feeling in the chest, after drinking.
Desire for food, with aversion to eating. Desire for food causing
a violent headache, unless satisfied at once. 100. Violent hunger.
Suffocative oppression after eating. Bloating of the stomach after
eating. Acidity after every mouthful of food. Aversion to food. 105.
Desire for cold water, ice. Sour eructation. Sense of coldness after
drinking, as if ice-water were rising and descending through an opening
in the left lung. She has to drink after every mouthful she swallows.
Watery vomiting in the morning. 110. She feels hungry, but is unable
to eat. Hunger, with continual vomiting, preventing one from appeasing
the hunger. Aversion to meat, bread. Desire for oranges, acid. Loss
of appetite. 115. Bread returns by the nose, and does not mix up with
the other kinds of food, for a month. Bread tastes flat, like the
poison. Fruit and cold drinks feel like ice in the stomach. Shuddering
and chattering of the teeth, after taking a cold drink. Suffocative
oppression while eating. 120. Eructations tasting like spoiled eggs.
The dinner distresses him. Pulling in pit of stomach. The food descends
violently into the stomach, which trembles.
STOMACH: Burning in the stomach. 125. Sensitiveness of the pit of the
stomach. Swelling of the stomach. Pulling at the cardiac orifice, with
sense of hunger and boring to the spine. Weight in stomach, with desire
to vomit, after eating.
ABDOMEN: Lancinations from the navel to the womb. Pains in the loins as
from a band, extending to the uterus. Colic spreading from the cœcum
to the rectum. Swelling of the inguinal glands. Colic, with urging to
stool. Borborygmi. 130. Falling of rectum. Distress in abdomen. Pressure
in right hypochondrium. Itching, drawing and pricking at epigastrium,
hindering breathing. The intestines turn about one another, and then feel
twisted as by a cord, and strung together in a knot, with strangulating
sensation in the abdomen. 140. Formication at the anus, as from worms.
Acute pains in the descending colon. Itching at the abdomen, especially
when walking. Sensation as if the blood in the abdomen were flowing
backwards, with violent pain and palpitations, succeeded by lancinations.
Sudden colic, with diarrhœa. 145. Bloat in region of diaphragm. Sense of
an iron bar pressing on the loins. Sensation in the abdomen as of a tube
which can be closed by a valve and through which liquid is poured into
the abdomen. Lancinations from both groins to the symphysis pubis.
STOOL: Blackish and froth, diarrhœa. 150. Lienteria. Constriction of
the sphincter. Watery, yellowish diarrhœa, with slime, also rumbling.
Discharge of black, liquid blood from the bowels. Constriction of the
sphincter, after bloody stool. 155. Bloody dysentery. Diarrhœa consisting
of bile and bloody mucus. Discharge of black blood at stool, with colic
as though the bowels would be twisted.
URINARY AND SEXUAL: Red urine, with cloudy sediment. Thick urine with red
sediment. 160. Pain in urethra while urinating. Red urine. Suppression
of urine. Discharge of mucus from the urethra. Itching excoriation on
the back of the penis. 165. Impotence. Lancinations and prickings in
the penis. Weight and swelling of the testes. The skin of the prepuce
is thick and inflamed. Discharge of prostatic fluid. 170. Discharge of
black blood between the menses. Prickling in the uterus, vagina and pubic
region. White, albuminous leucorrhœa. Weight at the uterus. Weight at the
vagina, after an attack of hysteric colic. 175. Horrid formication at the
vulva. Discharge of black blood from the womb. Metrorrhagia. Itching in
the vagina. Premature menses. 180. Weight in the vagina, with acute pain
preventing her from going up-stairs.
BRONCHIAL: Coryza from the least currents of air. Constant cough. Fit
of dry cough which ends in raising black blood, with tearing pains in
every part of the lungs and especially in right side, superiorly. Taste
of blood in mouth before coughing. 185. Loose cough. Hoarseness. Chronic
loss of breath on going up-stairs. Violent distress in the chest.
Sensation as if the pleura would be torn, and as if the lungs would be
split by force.
CHEST: 190. Spitting of black blood, with painful tearing as if
proceeding from the heart. Constriction of the chest. Stitches in upper
part of each lung. Painful pulling in right lung on which account he is
unable to lean to the right side. Dull pain in right lung, worse when
walking. 195. Dull pain in right lung, worse when walking, with rush of
blood to the throat. Prickling and pulling in right lung. Palpitation of
the heart.
BACK: Lancinations in the dorsal muscles. Pain in the whole spinal
marrow. 200. Pressure between the shoulders. Coldness in the back.
Lancinations from the occiput to the sacrum, with pain in the temples.
NECK: Sense of excoriation at the nape of the neck. Painful pressure
at nape of neck. 205. The parotid glands are painful. Bruising pain in
sides of neck. Twitching in the parotid glands. Tension in nape of neck.
Stiffness of the neck. 210. Beating in the nape of neck, like the ticking
of a clock. Throbbing of the external carotid. When raising the hand to
the right side of the neck, a penetrating pain in feet, spreading to the
ear. The neck remains twisted when turned.
UPPER EXTREMITIES: Painful drawing at the inner side of the arm. 215.
Itching under the axilla, with tetter. The arm and hand are swollen,
blueish, covered with red spots, also the right leg and foot. Bruising
pain in the deltoid muscle. Painful drawing from axilla to wrist, at
inner side. Crampy constriction at the bend of the elbow. 220. Pains in
the elbows. Warmth in the hollow of the hand, after dinner. The right
hand feels numb, with a stitch through the metacarpus. The hand looks
congested, and is as if paralysed. Lancinations in the back of the hands.
225. Pulling in right hand. Prickling in the back of the right hand.
Burning in the hands while preparing the drug. The right hand feels as if
paralysed. Smarting under the nails. 230. The tips of the fingers peel
off. Redness and pain under the nails, the parts look as if raw. Crampy
constriction in the phalanxes and under the nails.
LOWER EXTREMITIES: The lower limbs give way. Acute pain in the right
iliac bone, as though the crest were swollen and inflamed. 235. Coldness
behind the thighs. Cramps in the calves. Lancination at inner side of the
knee. Cramps in the calves. Icy-coldness of the right legs. 240. Pains
in the knees, especially the left, as if bruised and contused. Sense of
spraining and stiffness in the knee-joint. Contusive pain at inner side
of left leg, with sensation as if something were rising and descending
in the tibia. The soles of the feet itch and peel off. Drawing-up of the
feet. 245. The left foot is swollen and blue, with red spots. Pain in
the right instep, as from walking. Lancinations in the soles of the feet
while seated, ceasing when walking. Dartings in the left fourth toe, now
and then. The heel peels off. 250. Prickling under the toe-nails.
FEVER: Sensitive to cold. Sweat on the forehead and nape of neck. The
arm shudders when dipping the hand in water. Shuddering of the arm when
dipping the hand into cold water. 255. Cold sweat all over.
SLEEP: Sleeplessness with uneasiness. Drowsy all day, no sleep at night.
Dreams about previous business. Nightmare, with congestion about the
head. 260. Anxious dreams. She dreams that she buries a dead person and
digs in his wounds with a knife. She dreams that she is fighting with a
man condemned to the galleys. She bites his hand during sleep. Dreams
about dead persons, she kisses them and falls into pits. 265. Dreams
about business.
CUTANEOUS: Red spot on the knee-pan. Boils on the arm. Crusty eruption
on the ear and cheek. Itching pimple on the legs. Vesicular eruption on
the feet. 270. Phlyctænæ here and there, especially on the extremities.
Pimples full of serum. Red pimples at the tips of the fingers. Miliary
pimples at the corner of the nose, upon a red base. Furfuraceous tetter
at the hairy scalp. 275. Suppurating pimples on the hands, fingers,
wrists, gums, &c. Numerous white pimples at the inside of the thighs,
inflamed in the day-time. Little pimples, followed by desquamation.
Yellow spots on the hand and fingers. Red tetter from the corner of the
right nostril to the cheek.
GENERAL: 280. Lassitude in the limbs. Congestion first to the chest, then
the abdomen. Stitch in the side. Pressure in left side, extending to the
vertebral column. Black blood spirts out of the finger when pricked.
285. The right side feels sensitive, with inability to rise in the
morning. Prickling as by spice, after triturating the drugs. Spirting of
arterial blood from the nose and ears. Pain in the right side, up to the
axilla. Stitch in the side. 290. Lassitude in all the limbs. At the least
contrariety the body shudders and the blood boils, with prickling. Cramps
in the right side. Quick lancinations in the back, sides and arms. The
extremities look blue, with reddish spots. 295. Paralysis of the right
side. The right side is numb and as if paralysed. Constrictive pain at
the bend of the elbow and knee. A change of position is painful. Aching
in left side. 300. Disposed to faint.
PEDICULUS CAPITIS (COMMON LOUSE).
It is scarcely necessary to give a description of this species which
is sufficiently known; we shall content ourselves with indicating the
principal characteristics which distinguish it from the other vermin
living on the surface of the human body. The louse is of an oval form;
flattened, longer than the crab-louse; its head is very small; its
thorax is composed of three not very distinct rings; the abdomen is all
of one piece, rounded off on the sides; it is ash-colored, whereas the
crab-louse is entirely white. The lice which have been made use of in our
provings, were taken from the head of a healthy child of five years.
Even before undertaking this experiment we expected to derive from it
important results. We entertained the belief that nature pointed out to
us the louse as a specific for the hereditary psora, in which belief we
were strengthened by the fact that psorin develops the lice-malady in
healthy persons. And we are now prepared to affirm that we have found the
louse one of the most useful agents in diseases of children. We offer the
following pathogenesis with a sincere pleasure which none but those who
devote themselves to such patient investigations, can appreciate.[2]
SYMPTOMATIC ARRANGEMENT ACCORDING TO HAHNEMANN.
MORAL AND MENTAL: 1. Depression of spirits. Dulness of feeling. Merry in
the evening. Very merry. 5. Irascible. Sad without cause. Sensation as if
raised off the ground by the hair. She is waked in the night by an attack
of dizziness, and inability to open the eyes. Dizziness while walking;
the cerebellum feels compressed, with beating and an acute pain on rising
in the morning.
HEAD: 10. Frontal headache. Headache at intervals, and abating all at
once. Headache in the evening. Heaviness of the head. Dulness of the
head, on rising, with beating in the right temple. 15. Heaviness at the
vertex. Violent headache, with dizziness and nausea, in the forenoon.
Violent headache, worse on stooping. Headache, with nausea, when walking.
Violent headache, and darting in the forehead, when walking. 20. Dull
pain in the head, on rising from bed. Headache and pressure at the
nasal eminence. Lancinations in the forehead. Dartings in the forehead.
Dartings in the right parietal bone. 25. Intermittent dartings in the
head, worse when stooping. Heat about the head. Itching of the hairy
scalp, in front. Contraction of the hairy scalp. Itching of the left
temple. 30. Itching of the hairy scalp. Shuddering over the left side of
the hairy scalp. Falling of the hair.
FACE: Dark complexion. Warmth of the face, afternoon. 35. Itching of the
beard. The face is red and bloated. Sweat in the face. Scarlet-redness
of the face. Itching at the right lower part of the face. 40. Heat in
the face. Tingling pain in the right cheek. Itching of the face and hairy
scalp. The left cheek is swollen.
NOSE: Tickling and prickling at the left wing of the nose. 45.
Inflammation of the nasal fossæ. Dartings in the root of the nose.
Itching of the tip of the nose.
EARS: Itching in the left ear, evening. Buzzing in the ears. 50. Hot
ears. Itching of the right ear. Whizzing in the ears, when whistling.
Cracking in the right ear, when eating.
EYES: Itching of the left eyelid. 55. Rings around the eyes. Dilatation
of the pupils. Smarting of the eyes as from weeping. The eyes feel weary,
are red and smart. Sensation as of sand in the eyes. 60. Smarting around
the eyes.
TEETH: The lower jaw feels tired, as from chewing too much. Dartings in
the right upper molares.
MOUTH: The lips are black and cracked. Dry, swollen and red lips. 65.
Burning and prickling on the border of the tongue, which is red and
cracked.
GASTRIC: Hunger, with inability to swallow; the pharynx seems to
contract, followed by fainting and desire to vomit, at noon. Aversion
to food. Constant nausea in the evening. Difficult digestion, with
contraction of the stomach. 70. Colic and diarrhœa after dinner.
THROAT: Sore throat, getting worse until evening. Scraping in the throat.
Sore throat every evening. Transitory choking, especially after supper.
75. Dryness of the throat. Scraping at the tonsils, when swallowing. Sore
throat, with constriction of the pharynx. Constant swallowing of saliva.
STOMACH, &c.: Stomach-ache, and dartings in the umbilical region. 80.
Violent colic. Slight colic.
STOOL: Soft stool, in the evening. Diarrhœa evening and next morning.
Hard and scanty stool.
URINARY, GENITAL, &c.: 85. Frequent and copious discharge of a watery,
yellow-greenish urine. Red urine. Yellow, clear urine. Frequent and
copious micturition. Continual erection, without desire. 90. Leucorrhœa.
Shifting pain in the uterus, in the evening. Painful stitch in the
uterus. Painful dartings, heat and itching in the uterus.
BRONCHIAL, CHEST: Thirst with hoarseness, towards evening. 95. Dry and
convulsive cough. Numbness while drawing breath. Pain in the breasts,
when drawing breath. Pain in the chest, worse when touched. Oppression on
the chest, in the evening.
BACK: 100. Tickling at the nape of the neck and between the shoulders.
Itching of the nape of the neck and back. Frequent pain in the loins,
when standing. Itching of the back.
EXTREMITIES: Bruising pain on the shoulders and arms. 105. Darting at the
arms. Itching of the forearm, in the evening. Pain in the bend of the
right arm. Itching of the forearm, in the evening. Tickling at the left
wrist. 110. Tickling at the wrists. Darting in the back of the left hand.
Itching at the backs of the hands. Itching of the back of the hand, with
redness and swelling of the veins. Tremor of the hands. 115. Darting and
itching at the first phalanx of the middle-finger. Tingling in the tips
of the middle and index fingers. Itching at the ring-finger. Itching of
first phalanx of right index-finger. Redness and itching at the right
hip. 120. Itching as from nettles in the bend of the thigh. The skin on
the left thigh peels off. Weakness of the lower limbs. The knee and upper
portion of the left lower limb feel tired. Violent lancination above the
left knee-pan. 125. Beating above the left knee-pan. Weariness of the
knees, especially the left, in the evening. Intense itching at the right
instep. Cold sweat at the feet, followed by excessive coldness, in the
evening. Ganglion under the foot, hard, swollen, and painful when walking.
SLEEP, FEVER: 130. Yawning. Drowsy. Uneasy sleep. Restless night.
Frequent waking. 135. Dreams about a mob, then amorous dreams with an
emission. Confused dreams about being pursued. He dreams that he is
dissecting one of his friends. He dreams that he sees people skate on the
Seine, in summer. She dreams that she sees acquaintances walk on water.
140. She dreams that she is sick in a dirty hospital, full of vermin;
water flows from her mouth. Dream about large-lice. She dreams that she
sees a large, black figure flying to the clouds. He dreams that he is
to die in a prison, whence he escapes by crawling out. Shuddering all
over, eight or ten times in succession. 145. Shuddering in the evening.
Shuddering and twitching. Fever.
CUTANEOUS: Pimples in the face, on the forehead, temples, chin, &c.,
vesicular with a black point in the centre. Miliary pimples at the nape
of the neck, on a red base. 150. Red pimples on the hands, passing off
soon. Red, inflamed pimples on the temples, shoulders, arms, legs.
Inflamed pimples on the back, red all around, white in the middle, with
a black point in the centre. Red inflamed pimples in the face, evening.
Smarting pimples on the back, white at their tips. 155. Red inflamed
pimples on the left shoulder and arm. White blotches above the left
breast. A number of small pimples on the left knee, black at the centre.
Small red pimples on the feet, on taking them out of the warm water. Red
pimples on the shoulders. 160. Small red pimples and itching on the right
calf. Red pimples with a black point in the middle, on the right side of
the neck. Miliary pimples on the calves, with itching. Miliary eruption
at the inside of the thighs, with itching. Former pimples at the nape of
the neck reappear. 165. Miliary pimples at the inside of the arms. White
pimples on the forehead.
GENERAL: Increase of physical strength. Swelling of the breasts, face,
and then of the whole body. Itching all over. 170. Face, hands and
feet look red. Tickling all over. Starting when sitting or lying in
the evening. Prickling all over, the whole day. Prickling all over,
especially at the front part of the thigh. 175. Weariness, dizziness,
faint feeling. Shivering, heat and dryness of the extremities. Itching of
the skin. Heaviness. Itching here and there, at night.
ELEIS GUINEENSIS. (JACQ.)
ELE.—PALM-TREE.
This species is spread all over South-America; it prefers cultivated
and sunny regions. Its trunk, which is from 25 to 30 feet high, is
covered by the persistent bases of the leaves. The top-leaves form a
thick tuft; they are large, pennate, with numerous folioles, ensiform,
alternate and sessile, attached to a strong rachis or spike the petioler
portion of which is garnished with long and sharp prickles. The flowers
are monœcious with a papyraceous perianthus having six divisions. The
male flowers have six stamens and three internal, erect and converging
folioles. They form ramose spathes in fusiform masses, placed between
the bases of the leaves. The female flowers are scattered; the ovary is
sub-cylindrical, surmounted by a short style with a bilobate stigma. The
fruit is oval, oleaginous, of a reddish yellow, surrounded by a hard and
angular pericarp. We have had it drawn of a large size in comparison to
the tree.
The fruit is triturated.
_First day_ (in the morning).—1. Ennui when alone. Bitter eructations.
Nausea. Drowsiness in the day-time. 5. Heat in the face. Throbbing pain
in the nape of the neck. (In the afternoon): pain in the middle of the
chest, as if pricked by pins. The breathing is embarrassed. Hammering
pain all through the head. 10. Vacillating gait. Loss of appetite.
Beating at the left arm, as if drumming on it with the finger.
_Second day._—Swelling of the right leg. Pain at the foot when walking,
whenever the foot touches the ground. 15. The same pain is felt when
touching the sole of the foot with the hand. Itching all over. He feels
strong and healthy. Small vesicles on the swollen leg. They break when
pressed upon, a little fluid spirting out. 20. Similar vesicles break
out on the left leg, arm and on various other parts of the body, without
any swelling. Merry mood, and laughter, even when alone. Remembrance
of a former shipwreck. Pain at the right knee as from a blow. Pains at
the right leg as if stung. 25. Continual itching all over. Pain as if
contused at the right side of the chest. Swelling, roughness and itching
of the skin of the right leg. The skin seems to be thicker. Acute pain at
the lower past of the left leg, as if a penknife had been thrust in.
_Third day._—30. The leg is less swollen. Colic after taking a cold
drink. Sadness. Pain at the bend of the knee, as from a blow. Desire to
vomit. 35. Violent colic. Weakness of the legs. At candle light the sight
becomes confused; when writing he makes the letters much larger than
usual. Throbbing pain in the calves. Breathing embarrassed, with a sigh.
40. Hammering pain at the tibia, nape of the neck and right foot. Pains
in the right shoulder, as from a blow. The sight is weaker than before.
Shuddering. White urine. 45. Blackish stool. Constrictive pain around
the neck as if a string were tied round. Good appetite. Out of humor.
Disobedient. 50. Wants to cry (weep).
_Fourth day._—The foot swells up more and more. Hammering pain in the
foot all the time. Lancinations in the throat when swallowing. Pain in
the abdomen, with sensation as if bruised. 55. Throbbing toothache.
Prickling in the larynx when drawing breath. He approaches his hand to
the fire without burning himself, whereas another person got burnt at
the same distance. An hour after, he feels very keenly that he had been
burnt. Stinging pain in the throat when swallowing saliva.
_Fifth day._—60. Bad smell in the mouth, after drinking water. Cough with
lancinations in the sides. Heat in the tongue when taking dinner, so
violent that he was obliged to stop eating.
_Sixth day._—The swelling of the leg increases. The vesicles on the right
leg and foot have dried. Other vesicles break out on the left leg and arm.
_Tenth day._—65. After a complete disappearance of all the symptoms, he
smells of the drug and afterwards takes 10 drops of the mother-tincture.
After taking them, bad smell in the mouth. Foul eructations. Merry mood.
Hammering in the temple. 70. Lancinations in the right side of the chest,
every 5 minutes, less during rest. Breaking out of vesicles which are
full of water and larger than the former ones. Itching every 5 minutes,
especially at the legs. On each side of the pit of the stomach the skin
appears thicker, with pain in the last false ribs as if a peg were stuck
in there.
_Eleventh day._—Swelling of the right eye. 75. He is unable to look at an
object steadily. Lancinations in various parts of the body, especially
when going down-stairs. Tumor at the left arm. No sleep at night in
consequence of the violent itching. Swelling of the left eye. 80.
Frequent diarrhœa. He vomits up a cake as soon as he had eaten it.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL AND MORAL: 1. Out of humor. Sad. Ennui when alone. Merry.
HEAD, &c.: 5. Hammering in the temple. Hammering in the head. Hot face.
EYES, EARS, NOSE: Swelling of the left eye. Swelling of the right eye.
10. Unable to look at an object steadily. Confused sight at candle-light.
Throbbing toothache. Bad smell in the mouth, after drinking water.
Violent heat in the tongue when taking his dinner.
GASTRIC: 15. Foul eructations. Colic, after taking a cold drink. Desire
to vomit. Nausea. Bitter eructations. 20. Loss of appetite. He throws
up cake immediately after eating it. Shootings in the throat when
swallowing. Bruising pain in abdomen.
STOOL: Black stool. 25. Frequent diarrhœa. White urine. Prickling in
larynx when drawing breath. Cough, with lancinations in the sides.
Lancinations in the right side of the chest, less during rest. 30.
Contusive pain at right side of chest. Embarrassed breathing. Pricking
pain in middle of chest. Constrictive pain around the neck. Throbbing
pain in nape of neck.
EXTREMITIES: 35. Swelling at the left arm. Beating at the left arm. The
hand gets burnt when holding it near the fire. Swelling of the right
leg. Throbbing pain in the calves. 40. Sharp sticking pain at lower part
of left leg. Swelling, roughness and itching of right leg. Pain at the
right leg as if stung. Bruising pain at the bend of the knee. Bruising
pain at the right knee. 45. Pain at the foot when walking or touching
the sole. Drowsy. Shuddering. Itching all over. The skin on each side of
the stomach appears thicker, with sticking pain in the last false ribs.
50. Itching every few minutes, especially at the legs. Vesicles here
and there, containing a fluid. Vesicles on the swollen leg, containing
a fluid. Hammering pain at the tibia, nape of the neck and foot.
Vacillating gait. Lancinations in various parts, especially when going
down-stairs.
MIMOSA HUMILIS. (WILD.)
MIM.
This species which is one of the smallest of the genus Mimosa, is found
in the prairies around Rio-Janeiro. Its stem is feeble, rather woody,
ramose, pubescent above and covered with very sharp prickles. The leaves
are bipinnate, the pinnæ being three- or four-paired, with small,
linear folioles, which close at the least contact; there are from 6 to
12 on each side of the spike. The flowers are small, sessile, forming
pretty silky tufts of a violet color. The fruit is somewhat triangular,
flattened, covered with long and stiff hairs, and surrounded by a
persistent pericarp, divided in two capsules, each of which contains one
seed.
_First day._—1. Twitching of the arm, which extends even to the chest.
Smarting pain in the legs, with lameness of the knee. Headache, with
weakness of the stomach. Stomach-ache after breakfast. 5. Drowsiness.
Flatulence and rumbling in the bowels. Yawning. Ptyalism. Shuddering.
10. Trembling of the legs. Lancinations in the legs and hands. Sneezing.
Coryza and discharge from the nose. Inflamed eyes. 15. Papulæ on the
left leg. Constipation. Depression of spirits.
_Second day._—Frequent waking at night. Dry cough in the morning. 20.
Stomach-ache after breakfast. Vertigo. Halo around the candle-light.
Numbness of the hands. Stiffness of the bends of the knees. 25. Sense of
heat in the head. The head seems larger than usual. Yawning. Indolent
indifference. Flatulent colic in the evening. 30. Frequent stools, with
colic. Papulous excrescence of the size of an almond on the right leg,
painful and itching. The same swelling at the instep. Drowsy in the
evening. Difficult breathing.
_Third day._—35. Inflammatory swelling of the scrotum. Itching of the
eyes. Pressure at the nape of the neck and the right temple. Papulous
excrescence at the tendo-Achillis. Dimness of vision. 40. Pain in the
sides of the head. Diarrhœa.
_Fourth day._—Swelling of the left ankle, with redness, tension and
lancinations. The excrescences on the leg disappear; similar ones appear
on the left arm. Easy stool. 45. Numbness of the arm and right hand,
passing off when moving the parts. The left eye becomes inflamed. Want of
breath.
_Fifth day._—Bleeding of the gums. The papulæ disappear. 50. Acute
lancinations, now in the legs, then in the arms. Violent lancinations in
the back as from a penknife. Drowsy in the evening, with frequent waking
at night.
_Sixth day._—Inflammatory swelling of the left hand. Shuddering.
_Eighth day._—55. Flatulence. Diarrhœa.
_Tenth day._—Diarrhœa. Whizzing in the ears.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: 1. Vertigo. Indifference. Depression of spirits. Pain in the
sides of the head. 5. Headache, with weak stomach. Heat in the head.
The head feels as if swollen. Coryza, fluent. Itching of the eyes. 10.
Dimness of sight. The left eye is inflamed. Inflamed eyes. Whizzing in
the ears. Bleeding of the gums.
GASTRIC SYMPTOMS, &c.: 15. Ptyalism. Stomach-ache after breakfast.
Flatulent colic. Diarrhœa. Easy stool. 20. Frequent stools with colic.
Rumbling. Dry cough. Oppressed breathing.
EXTREMITIES: Pressure at nape of neck. 25. Lancinations in the back.
Twitching of the arm. Smarting in the legs, with lame knee. Trembling of
the legs. Lancinations in the legs and hand. 30. Stiffness of the bends
of the knees. Numbness of the arm and right hand. Lancinations in the
legs and arms. Inflammatory swelling of the left hand. Swelling of left
ankle, with redness. 35. Yawning. Drowsy. Shuddering. Papulæ on left leg
and arm. Papulous excrescence on the right leg and instep.
CERVUS BRAZILICUS (NOBIS).
CERV.—BRAZILIAN STAG; GUAZOUTI. PORTUG: GOUAZOUPITA.
This stag whose forms are extremely fine and graceful, inhabits the
forests of Brazil. Its size is about the same as that of our stag.
Its skin the color of which never changes, is of a brownish fallow,
being rather lighter towards the abdomen, the posterior part of the
thighs and the tail. The inferior surface of the lower jaw, the part
above and below the eyes, the interior of the ears and the abdomen are
white; a black line encircles the jaws and gradually disappears under
the lower one. The eyes of the guazouti are black, it has no canine
teeth; its mouth, which is very slender, tapers to a muzzle. The horns
which, in every case, are not very high and extremely regular, are at
first straight; they curve forward in the second year, send forth three
antlers, the anterior being placed about two inches above the burr,
which is turned a little inward, and the other two at the superior and
posterior part of the staff. The horns become bigger as they grow older,
but the number of antlers remains the same. We triturate the skin, which
should be used fresh and covered with the hair.
_First day._—1. Copper taste in the mouth, and a sensation of heat in
the throat when taking the drug. Light or comatose sleep, with dreams
about men who are dressed in black, about pistol-shots, imprisonment.
Uneasiness. At five o’clock in the morning, the head feels heavy and
dull, especially the front part. 5. Constant heat in head. At half past
nine the left side of the tongue feels hurt. Languid feeling, he wants to
lie down. Unable to work. Sensation of goose-flesh as if some one were
cutting cork close to him. 10. Repeated yawning. He feels cold though he
is wrapt up well. Slumbers from half past two to three o’clock. Slight
diarrhœa. 15. The heat in the face increases (at four o’clock). Dark-red
spots, with inflammation of the right side of the face. Head dull and
heavy. Heat about the legs. At six o’clock, slight pain around the navel,
which, however, does not last long. 20. Pricking at the right nasal wing.
At noon, the head feels compressed as by a band tied together at the
nape of the neck. Bruising sensation in the left toes. Frequent pain,
now in the left buttock, and then in the thigh. The left leg feels weak.
25. Small callosity above the internal ankle of the left foot. General
feeling of weariness and of being bruised.
_Second day._—Restless sleep as the first night. Wakes several times at
night, always preoccupied with the idea of quarrelling with somebody
who frightened him. The dulness continues. 30. Weight at the forehead.
Tight feeling at the inner side of the right leg, with red spots.
Appearance like incipient erysipelas. Shuddering with twitching. Yawning.
35. Intermitting pain in the right groin after walking. Taste of doughy
bread in the mouth. The sight is very sensitive to light, he cannot open
his eyes in a spot which is illumined by the sun. At eight o’clock in
the evening, pain in the right groin as if pricked with a pin, in the
direction of the joint, for a quarter of an hour. The same pain is felt
in the navel in a recumbent posture.
_Third day._—40. Numbness of the arm on which he had been lying at night.
Hardness of the left leg, with lancinations. Mottled appearance of the
face. Red and humid spots on the left leg. Quiet and short sleep, he
wakes four times at night. 45. Dulness of the head; same weight at the
forehead. Heat in the right leg, where the red spot is; this is sensitive
to contact. Taste as of doughy bread in the mouth. Depression of spirits
in the day-time. Erection in the evening, with desire to lie down.
_Fourth day._—50. Numbness of the hands and legs. Uneasiness in the left
leg.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: 1. Depression of spirits. Weight at forehead. The head feels
heavy and dull. Heat in the head. 5. The head feels compressed as by a
band tied behind. Sensitiveness to light. Left side of the tongue feels
sore. Taste of doughy bread. Copper taste in mouth, with heat in throat.
10. Mottled appearance of the face. Hot face. Pricking at right nasal
wing. Pain in right groin after walking. Pricking pain in the right groin
and navel. 15. Slight pain around the navel. Diarrhœa. Erection.
EXTREMITIES, &c.: Numbness of the arm on which he had been lying. The
left leg feels weak. 20. Tight feeling at inside of right leg, with red
spots. Hardness of the left leg, with lancinations. Heat at the legs.
Heat in the right leg, where the red spot is. Bruising sensation in
left toes. 25. Uneasiness in left leg. Restless sleep. Yawning. Quiet
sleep, with frequent waking. Dreams about men dressed in black, about
imprisonment, &c. 30. Yawning. Shuddering with twitching. Sensation of
goose-flesh. Cold feeling. He feels weary and sore. 35. Languor. Numbness
of the hands and legs. Incipient erysipelas. Callosity above the left
inner ankle. Red and humid spots on left leg. 40. Dark-red inflamed spots
in face, right side.
GUANO AUSTRALIS.
This substance, which has been used for some years past as manure, is
found on the coasts of Patagonia—and principally on the Lobos Island
near the coast of Peru. We have proved the different varieties of guano,
and likewise the crystalline particles formed by the condensation of
ammonical vapors which rise from the guano in abundance. Our hope to
discover in these crystals a more active normal agent, has not been
realized, so that, in the end, we have found the freshest possible guano
preferable for medicinal purposes. It is triturated in the same way as
all other substances.
_First day._—1. Internal shuddering for three minutes in the morning.
Violent headache. Pain in the forehead when inclining the head forward,
at 6 o’clock in the morning. Violent itching at the back, and painful
smarting after scratching, at 7 o’clock in the morning. 5. Formication in
the right nasal fossa, at 7 and a half o’clock. Pain with pinching behind
the ears, at 8 o’clock in the morning. Dizziness, objects turn from below
upward, at 9 o’clock in the morning. Nausea with profuse flow of saliva.
Pale face with faint feeling, at noon. 10. Lassitude, at half past two in
the afternoon. Desire to vomit, at half past two in the afternoon. While
eating, pain at the pit of the stomach and desire to vomit. Profuse sweat
all over, after eating. Aching in the forehead and temples, worse when
stooping, at half past three. 15. Pain at the styloid process of the left
wrist. Pain in the lungs which stops the breathing, for three minutes.
Swelling of the right index-finger. Itching of the genital organs. Water
feels extremely cold to the hands, they feel like ice when keeping them
in the water a little longer. 20. Pain at the feet which prevents one
from pressing them to the ground, at 5 o’clock in the evening. Red spot,
with itching at the back, and smarting pain after scratching. Violent
headache as if the head were incased in iron.
_Second day._—Beating at the left commissure of the lips, at 6 o’clock in
the morning. Itching in the right nostril and frequent sneezing, for one
hour, at half past 6 o’clock. 25. Great weakness. She remains at the spot
where she happened to have located herself.
_Third day._—Painful ganglion on the left arm, with redness and itching;
when scratching the arm, it remains insensible until the skin was off;
lasts for half an hour, at 6 o’clock in the morning. Headache: he feels
as if the head were opened, at 8 o’clock in the morning. Smarting
ganglion below the right calf, hindering walking, and lasting until night.
_Fourth day._—30. Nausea, one cannot bear seeing persons eat, at 7
o’clock in the morning. Painful ganglion at the left elbow. Small itching
pimples. Violent beating of the heart; feeble breathing, for five
minutes. Large hard and red place on the back, with pricklings as from a
thousand pins. This sensation commences at 9 o’clock and lasts all night.
_Fifth day._—35. Profuse sweat on the arms and hands; the skin on the
thighs is insensible; a prick is not felt; for two days they are covered
with little pimples. Cramp at the pit of the stomach before eating.
_Sixth day._—Violent pain at the right knee, as though pieces of flesh
would be torn from him, at 7 o’clock in the morning. Burning under the
soles of the feet, she cannot keep her shoes on. Cramp at the left thumb,
for an instant.
_Seventh day._—40. Sensation as if the gums were cut with penknives,
after which they bleed for half on hour, at 6 o’clock in the morning.
Formication in the right nostril, for five minutes, at 10 o’clock.
Sensation of hammering in the nape of the neck, at 3 o’clock in the
afternoon. Pain in the abdomen as if pierced by sharp points, at 9
o’clock in the evening.
_Eighth day._—Tongue white and thickly coated. 45. Bitter bilious taste
in the mouth, at 6 o’clock in the morning. Deep sleep. She dreams that
she is playing with wild beasts.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: 1. Dizziness, objects turn from below upward. Headache.
Headache as if the head were encased in iron. Headache as if the head
would split. 5. Aching pain in forehead and temples. Pain in forehead
when inclining the head forward. Pale face, with faint feeling. Pinching
pain behind the ears. Cutting in the gums, followed by bleeding. 10.
Tongue coated white. Beating at the left commissure of the lips.
Formication in right nasal fossa. Itching in right nostril, with sneezing.
GASTRIC, &c.: Bilious taste in mouth. 15. Cramp at pit of stomach before
eating. Nausea, cannot bear seeing people eat. Pain at pit of stomach,
with desire to vomit, while eating. Sweat all over, after eating. Nausea,
with flow of saliva. 20. Desire to vomit. Sharp piercing-sticking pain in
abdomen. Itching of the genital organs. Palpitation of the heart. Pain in
the lungs, arresting the breathing.
EXTREMITIES, &c.: 25. Hammering sensation in nape of neck. Itching of
the back, with smarting after scratching. The hands feel like ice in
cold water. Pain at the left wrist. Swelling of the right index-finger.
30. Cramp at the left thumb. Burning at the soles. Pain at the feet when
pressing them to the ground. Pain at right knee, as if the flesh would be
torn off. Internal shuddering, in the morning. 35. She dreams that she
is playing wild beasts. Itching, red spot on the back. Hard and red spot
on the back, with pricklings. Smarting ganglion below the right calf.
Painful ganglion on left arm, with redness. 40. Weakness, no desire to
stir. Lassitude. Profuse sweat on the arms and hands, with insensibility
of the skin and little pimples.
HIPPOMANE MANCINELLA. (L.)
HIPP. MANCINELLA VENENATA, TUSS.
Although the poisonous properties of the mancinella have been very much
exaggerated, it is nevertheless a very poisonous tree, which, happily,
becomes more and more rare, owing to its being rooted up with great care
wherever it shows itself. It is a tree from 12 to 15 feet high, with
a trunk having a white and soft wood and covered with a greyish bark.
Its branchy top gives it the appearance of a European fruit-tree. Its
leaves are alternate, oval-acute, somewhat cordate at their base, with
fine indentations, and a red gland at their apex. They are attached
to long petioles; stipulate while young. Flowers monoïchous, forming
long terminal spikes, the male flowers being above, the female below
or at the axilla of the leaves. The male flowers have a bifid perianth
whence emanate the stamens, the united filaments of which form a column
that supports the anthers. The female flowers have a perianth with two
or three divisions and a rudimentary foliole; the ovary is round and
superior; style straight, terminating in 6 or 7 red, radiating, reflexed
stigmata. The fruit is round, pulpy, from 5 to 6 inches in diameter,
umbilicate at the top, and inclosing a wooden kernel with seven monosperm
compartments.
The fresh leaves are triturated. When we were informed that a mancinella
had been discovered near Rio, we requested Mr. Ackermann, a pupil of
the institute, to repair to the spot for the purpose of verifying the
identity of the plant, and collecting its juice. Having accomplished his
mission, he drunk a portion of the liquid, on the 10th of January, 1847,
in a public sitting of the institute. He was joined in the proving by
several of our pupils. Some of the following symptoms were so violent,
that they had to be counteracted by antidotes. The pathogenesis of the
mancinella is one of the most precious additions which our Brazilian
provers have furnished to our Materia Medica.
Prover: M. E. T. Ackermann.
FIRST PROVING.
_First day._—1. Merry mood, desire to sing. Is disposed to take every
thing in good part. Buzzing in the ears and whizzing like the wind, when
walking. Urine scanty and whitish. 5. Sensation of heat and trembling in
the chest. Constant eructations like volumes of air. Watery vomiting.
Violent pain in the abdomen, as if he had been struck by the point of a
stick.
_Second day._—10. Heavy sleep, and late waking. Evanescent ideas.
Sensation of paralysis immediately after rising, his hand trembles a good
deal; he is unable to open the door of his room. Absence of thought.
Disposed to be silent. Deep tranquillity of mind, in the morning. 15.
Sadness. Drowsy after breakfast. Embarrassed breathing when falling
asleep again. Redness of the skin. Sweat in the palm of the hands whereas
the rest of the body is perfectly dry. 20. Pain at the lower part of
the head, and weight as if he had knocked it against any thing. Small
pimples. Beating pain at the left side of the neck. Pain all around the
neck like beats with a hammer. Pain at the right side of the head while
hearing the strokes on an anvil, he felt as though he were struck with a
hammer. 25. Pain at the nape of the neck and forehead when stooping; it
is a dull, confused pain which he cannot describe. In the day-time the
hands become red. Sense of weight over the eyes. His nose is looser than
usual. Pain all round the head as from a blow after having remained in
the sun for a time. 30. Redness and heat of the ears. Alternate hunger
and loss of appetite. Weak stomach. Loathing. Profuse urine, but always a
little white. 35. Acute pain with weight in the pit of the stomach, for a
minute. Eructation during an expiration, like a volume of hot air, which
ascends to the mouth with a feeling of oppression. Metallic taste in the
mouth. White expectoration. Beating pain in the abdomen after breakfast.
40. Disagreeable sensation while hearing the noise of a saw. When hearing
blows with a hammer the counter-shock is felt in the whole body. He
alternately lays himself down and raises himself again. Swelling of the
veins of the hands. Constant pain all day, in the wrist and metacarpus,
as if strings were tied round very tightly. 45. Three slight beats on the
arm, as if touched with the finger. Easy stool. The face is yellow and
the body red. Copious emission of wind. Weak all over in the day-time.
50. Two attacks of colic and diarrhœa, with pulling and pinching in the
bowels, at midnight.
_Third day._—Sad, then merry dreams. Every thing is unpleasant to him.
The headache continues and renders him impatient. Feeling of tenderness
and deep pity. 55. Profuse and whitish urine. The chest dilates a good
deal, when drawing breath, even with the mouth closed. The chest feels
bruised, with embarrassed respiration. The constrictive pain at the wrist
shifts to the middle of the arm for an hour, after which it returns again
to the wrist.
_Fourth day._—Lancinating pain in the left temple. 60. Buzzing in the
ears, and drumming noise when walking against the wind. Lancinating
pain in the chest. Prickings through the heart. The moral emotions are
accompanied by an indescribable malaise, beating pain in the chest and
loss of speech. When making the least exertion, he is attacked with
violent cough and painful prickings in the throat. 65. When commencing
to talk, a sudden suffocation and violent beatings in the chest.
Suffocation and beatings in the chest when attempting to cough. Beating
pain in the head and nape of the neck, with inability to bend the head
forwards for the purpose of writing. Weak chest. Thirst every hour in
the day-time; desire for water, with aversion to wine or any other
liquor. 70. The weakness increases. Sadness. Colic and diarrhœa. Full
and frequent inspirations. Urine clear and abundant, but whitish. 75.
Lancinations in the bladder when commencing to urinate, he feels relieved
after urinating. Pulling and dragging pain in the bowels.
_Fifth day._—Headache. Pain in the chest when making the least motion.
The breathing is no longer embarrassed. 80. Extraordinary desire to
smoke. Pricking in the feet when sitting. Weakness all over. Pain in
the bends of the knees as if bruised. 85. Constriction round the thighs
and legs as if a thread had been tied around. Lancinations in the
groins. Sexual desire. Continual thirst in the day-time. Dry mouth. 90.
Depression of spirits. Sadness. Cold extremities. Profuse and clear
urine. Deep sleep in the day-time. 95. Aversion to work.
_Sixth day._—Dream about ghosts and phantoms. Headache. Sad in the
morning. Increasing thirst in the day-time, until evening. 100. Heaviness
all over. Profuse and clear urine. Loathing of every thing. Aversion to
work. Desire to lie down.
_Seventh day._—105. Headache with vertigo, especially in the morning,
after eating a piece of bread. Sensation as of a blow in the abdomen,
followed by stool. Formication in the right hip, and lancinations when
walking. Continual thirst. Sadness. 110. Clear and profuse urine.
_Eighth day._—The urine becomes natural again.
_Ninth day._—The previous symptoms disappear. Active mind, disposed to
work. Good appetite.
_Eleventh day._—115. Tetter of an inch in diameter on the left arm; it
disappears on the following day. Beating pain in the neck, abating for
a few moments by reclining the head. Pricking in the mouth when eating
bread. Desire to remain lying. Frequent stool. 120. Swelling of the left
ankle. Pricking for two hours at the left knee-joint.
_Twelfth day._—Lancinating pain in the head. Heaviness at the head. Pain
at the head after thinking, as from bandaging the head from temple to
temple with the skin of a bladder. 125. Confused pain in the head when
writing. Lancinating pain in the head, as soon as one sets about eating.
Contusive pain at the clavicles, when turning the head right or left.
SECOND PROVING.
_First day._—(The drug was taken at half past seven in the evening.)
One hour after, violent headache, with painful lancinations. The pains
continued all night, with sleeplessness.
_Second day._—130. The headache continues, especially at the temples
and above the eyes. Acute pain at the elbow-joints. Taste of blood in
the mouth. Rheumatic pain at the shoulder-blade. Repeated, violent
lancinations in the right side of the abdomen. 135. Lancinations at
irregular intervals, in the left shoulder-blade and muscles, from the
left side of the chest. Headache all day. Constant dryness in the throat.
Taste of blood in the mouth all day.
_Third day._—Painful lancinations in the head, temples, and over the
eyes. 140. Intense lancinating pains in the left side. Lancinations
in the hypochondria and shoulder-blades. The pain at the elbow-joint
continues. Lancination in the right knee-joint. Excessive heaviness
and dulness of the head. 145. Constant drowsiness. Incessant headache.
Intense, lancinating and constrictive pain in the muscles of the upper
part of the right arm, for more than an hour. Continued formication in
both feet, especially the left. Taste of blood in the mouth, as if blood
had ascended in the throat, and had left the taste of it in the mouth.
150. Frequent and violent lancinations in the abdomen and bowels. Almost
complete loss of appetite. Comatose, constantly drowsy. The head feels
very heavy, with constant pain in it.
_Fourth day._—No sleep at night. 155. The headache becomes intolerable.
Taste of blood in the mouth. Attack of diarrhœa, with pain and tenesmus.
First a natural stool, followed by frequent, painful discharges, first
of black, fetid substances, then of a watery liquid; the attack lasts
upwards of two hours. Lancination in the muscles of the right knee, also
in the ribs and right side. 160. Pains in the hypochondria. Lancinating
pain in the bowels. Lancinating pain in the left shoulder. The headache
continues. Complete loss of appetite. 165. No sleep.
ARRANGEMENT ACCORDING TO HAHNEMANN.
1. MENTAL AND MORAL: Taciturn. Deep repose of mind. Evanescent ideas.
Merry. 5. Sadness. Feeling of tenderness. Sad, then merry dreams.
HEAD: Heaviness and dulness of the head. Lancinating pain in the head.
10. Pain at the head, as if bandaged all round, after thinking. Headache
with vertigo, after eating bread in the morning. Headache, especially
in the temples, and above the eyes. Violent headache with painful
lancinations. Pain as from a blow all round the head, when staying in the
sun. Weight above the eyes. 15. Pain at nape of neck and forehead, when
stooping. Pain and weight at lower part of the head. Lancinating pain in
left temple.
FACE, GASTRIC: Face yellow, and body red. 20. Buzzing in the ears.
Redness and heat of the ears. Buzzing and whizzing in the ears. Dry
mouth. Loathing. 25. Loathing of every kind of food. Loss of appetite.
Watery vomiting. Desire to smoke. Thirst every hour, with aversion to
wine or liquor. 30. Alternate hunger, and loss of appetite. Pricking in
the mouth when eating bread. Eructations, like volumes of air rising
upwards. Hot air rises during an expiration. Taste of blood in the mouth.
35. Metallic taste in mouth. Dryness of the throat.
STOMACH, BOWELS: Weak stomach. Acute pain and weight in pit of stomach.
Lancinations in the groins. 40. Pulling and dragging pain in the bowels.
Sensation as of a blow in the abdomen, followed by stool. Violent
lancinations in right side of abdomen. Pains in the hypochondria.
Lancinations in abdomen and bowels. 45. Sticking pain in abdomen. Beating
pain in abdomen, after breakfast. Flatulence.
STOOL, URINARY, GENITAL: Easy stool. Colic and diarrhœa, with pulling and
pinching in the bowels. 50. Diarrhœa, with pain and tenesmus. Natural
stool, followed by painful discharges, first of black and fetid, then of
watery, liquid substances. Frequent stool. Dartings in the bladder, when
commencing to urinate. Profuse urine, rather white. 55. Urine scanty and
whitish.
CHEST: Full and frequent inspirations. Weak chest. Contusive pain at
the clavicles when turning the head. Sense of heat and trembling in the
chest. 60. Suffocation and beating in the chest, when attempting to
talk or laugh. Violent cough and painful prickings in the throat, after
the least exertion. The chest feels bruised, with oppressed breathing.
Lancinating pain in the chest. Considerable dilatation of the chest, when
drawing breath. 65. Embarrassed breathing. Prickings through the heart.
BACK, EXTREMITIES: Beating pain at left side of neck, or all around it.
Pain at right side of neck as if struck with a hammer. Rheumatic pain at
the shoulder-blade. 70. Dartings in the left shoulder-blade and muscles,
from the left side of the chest. Beating pain in the neck, abating when
reclining the head. Lancinating pain in the left shoulder. Intense
darting and constrictive pain in the muscles of the upper part of the
right arm. Tetter on left arm. 75. Slight beats on the arms as with a
finger. Acute pain at the elbow-joints. Constrictive pain in wrist and
metacarpus, all day, shifting to the arm. His hand trembles after rising,
as if paralyzed. Sweat in the palm of the hand. 80. The veins of the hand
are swollen. Formication in the right hip, and lancinations when walking.
Constrictions around the thighs and legs. Bruising pain in the bends of
the knees. Pricking at left knee-joint. 85. Dartings in the right knee
joint. Swelling of the left ankle. Pricking in the feet when sitting.
Formication in the feet.
SLEEP, &c.: Heavy sleep. 90. No sleep at night. Dream about ghosts and
phantoms. Constant drowsiness. Deep sleep in the day-time. Red skin. 95.
Pimples. Desire to lie down. Aversion to work. Indescribable malaise,
with beating pain in the chest and loss of speech. Nervousness, the blows
of a hammer produce a counter-shock in the whole body. 100. Beating
pain in the head and nape of the neck, with inability to bend the head
forwards. Cold extremities. Heaviness all over. Painful dartings in the
head, temples, and above the eyes. Darting in the muscles of the right
knee, ribs and right side. 105. Weakness in the day-time.
HURA BRAZILIENSIS. (WILLD.)
HURA.—ASSACÙ.—OASSACÙ.
This plant inhabits the equatorial regions of South-America, the
provinces of Para, Rio-Negro, and the neighborhood of the Amazon, where
it is very frequent. It resembles the hura crepitans; its leaves are
alternate, somewhat cordate, rounded, glabrous, serrate; rolled up and
stipulate while young. The petiole is provided at its top with two large
glands. Flowers monoïchous; the male flowers having a short, urceolate
perianth, and covered with a scaly bract; they form elongated, peduncled,
terminal husks. The female flowers, which are twice as long as those
of the hura crepitans, have their perianth resting against the ovary,
which is surmounted by a long and infundibiliform style, terminated by a
stellate stigma; they are solitary and placed near the male flowers. It
is from this tree that the Indians draw the milky juice called Assacù by
the Brazilians.
A man affected with lepra, and who had sought refuge in the solitary
regions of the Amazone, took, by the advice of an Indian whom he met
there, a considerable quantity of a juice known under the name of Assacù,
flowing from the trunk of a tree, which has been described by Willdenow,
under the name of hura braziliensis. He was cured; and the president of
the province of Para, informed the imperial government of it. Since then,
this juice has been very generally used by leprous patients without,
however, curing them.
The first and third provers of this drug, on a voyage to Brazil, in
1842, had both been attacked with the lepra. Under homœopathic treatment
they seemed both to have got well, though one might have inferred from
the gravity of their symptoms, that they had been palliated rather than
cured. The frightful symptoms of compression of the spinal marrow, which
supervened in the case of one of the provers, point to the Assacù as a
powerful remedy for various forms of myelitis. The symptoms of nervous
excitement, the twitching, the irritability of the temperament exhibited
by all the provers, favor the doctrine that the lepra is a particular
lesion of the nervous system. If the exanthems and the insensibility
of the skin characteristic of the lepra, have been less marked in our
provings, it is undoubtedly because these phenomena belong to some
chronic form which a continued use of the drug and a real poisoning are
alone capable of producing.
These four provings have been instituted with a single drop of the
fifth attenuation. It is our rule to avoid repeating the dose lest the
chronological succession of the symptoms which we regard as important,
should be disturbed. We do not believe that repeated doses can do much
good, and if a prover should not experience any effects from one dose, we
should prefer dropping this proving, and resort to some other drug, to
which his organism should be more sensible.
First prover: Aug. Joly, 29 years of age, bilious-nervous temperament,
healthy constitution.
_First day._—Took one drop of the 5th attenuation at ten o’clock at night.
1. One hour after, itching at the ribs and sternum, at the biceps and
the posterior parts of the right arm. Doughy mouth, in the morning, on
waking. Dreams about a ball, about houses in process of erection. In
the morning, itching at the arms, legs, outer parts of the tibia. 5. The
upper and lower eyelids are inflamed and blueish. Itching at the right
arm, at the lower and inner portion of the humerus, owing to a little
pimple which is forming. Taste of blood in the mouth. Whizzing in the
ears, especially the right. Clusters of miliary pimples on the back,
arms, legs and chest. 10. Irritated by the least contrariety. Desire
to vomit, sick stomach. Rheumatic pain at the left arm. He looks weary
as if he had been carousing all night, though he slept well all night.
Pinching at the right side of the tongue. 15. Lancination in the canal of
the urethra. Prickling around the eyes, and especially around the right
one. Sensation as if small pimples would break out on the inside of the
eyelids. Nervous beating in the eyelids. Rheumatic pain at the sacrum,
especially when stooping. 20. Contusive pain at the lumbar region.
Miliary eruption in the joints.
_Second day._—Dry mouth in the morning. Acute pain in the lumbar region
and at the sacrum, as from a fall. Smoky taste of the water which is
drank at breakfast. 25. Pain in the ileo-femoral articulation. Pain all
along the left thigh. Sneezing, and frequent blowing, as when a catarrh
is about setting in, followed by involuntary discharge from the nose of
a lemon-colored mucus, with tickling. Constant pain in the lower part
of the lumbar regions, worse when stooping or sitting down. Lancinating
pain at the top of the head. 30. Slight desire to vomit at eleven o’clock
in the morning. Dizziness. He dreams that he was swimming in a river
with warm and dark-green water; afterwards that he was on a plantation
in Brazil, where men drew water from a yellow pond. Moist, intermittent
heat, mounting every fifteen minutes from the feet to the face. Prickling
at the right eye. 35. Sense of heat mounting to the clavicles. (At a
quarter of ten o’clock:) Dry nose, he cannot blow it; with itching at the
interior of the nose.
_Third day._—In the morning, the pain at the sacrum had disappeared. (At
ten o’clock and a half:) The pain at the sacrum returns worse, after
moving a box. Burning at the right index-finger, a red spot extending
from the nail to the second phalanx. Numbness; almost amounting to
insensibility. 40. (At half past twelve:) Pain as from a splinter under
the thumb-nail. In the evening, tickling under the arms and along the
dorsal spine. No sleep at night, frequent waking, feverish agitation.
_Fourth day._—Heat in the hands, in the morning. At two o’clock, a small
vesicular pimple on the back of the left hand; for four hours. 45.
Stiffness in the trapezoid muscle, near its attachment at the occiput.
Pain at the left forearm as from a blow. Small vesicular pimples, and
itching at the ribs, arms, and at every prominent process of the bones.
_Fifth day._—In the morning, the pimples on the arms have almost
disappeared; there remains only a little itching at the sternum. Heat at
the tips of the right fingers. 50. Sensation as if a small portion of the
nail of the right index-finger had become detached. At half past six in
the evening, heat and passing sweat. At half past seven in the evening,
sensation of burning, smarting on the left side of the chin, in the
beard, as from an incipient tetter. Sensation under the masseter muscle,
as from a recent blow on the parotid. At eight o’clock in the evening,
the spot becomes sensible to contact; a small swelling is observed
extending below the zygomatic arch. 55. Sensation at the supinator muscle
of the forearm, as from an incipient tetter. Small pimples on the inner
surface of the lower lip. Stiffness of the trapezoid muscle and the neck.
Prickling as from dust, at the border of the lower lid of the right eye.
60. Itching at the back, legs, arms, at the same time.
_Sixth day._—Fleshy excrescenses on the inner surface of the lips. At
four o’clock, weariness in the legs, in going up-stairs. At eight o’clock
in the evening, painful stiffness of the neck. The pain in the masseter
muscle, which had already decreased in the morning, disappeared entirely
in the evening. Weight in the testicles in walking, at five o’clock in
the evening. 65. Taste of blood in the throat before breakfast.
_Seventh day._—Itching at the right lower eyelid, as if a pimple would
appear. At three o’clock, sensation as of dust in the left eye. Sense of
weight at the eyes, as if they had been strained.
_Eighth day._—No sleep all night. 70. Pressive pain at the cranium. Heat
in the nails of the left hand.
_Ninth day._—Straining sensation in the upper part of the sacrum,
preventing him from standing erect, at noon. Taste of blood in the throat
before breakfast. Sputa mixed with blood. 75. Sense of giving way in
the knee-joint, in going down-stairs, at two o’clock. At four o’clock,
pain in the renal region, which keeps increasing; it decreases at five
o’clock. Prickling in the left eye, and intolerable itching, with nervous
irritation which spreads to the heart, but passes off soon.
_Tenth day._—Prickling in the left eye as from dust. Smarting sensation
in the beard as from a pimple at each hair, at nine o’clock. 80. Burning
sensation at the inner canthus of the right eye, at half past nine in the
evening. The carunculæ lachrymales look inflamed.
_Eleventh day._—Itching at the anterior surface of the tibia, at
night, and smarting sensation as from a tetter. Appearance of a small
red circle, with a small dark-red pimple in the middle; followed by
peeling off. Itching at the hairy scalp, especially behind and in the
mastoid process, as from a tetter. 85. Sensation as if he had torn off a
hang-nail, or as from a splinter in the ring-finger of the left hand. At
ten o’clock, smarting at the bend of the right elbow, on the outside.
_Twelfth day._—Tickling at the left arm, with small vesicular pimples.
Itching in the beard, with small pimples which form a crust under
the chin. Itching and small crusty pimples on the hairy scalp. 90.
Constrictive sensation at the anus; at half past five o’clock.
_Thirteenth day._—Painful sensation at the upper and lateral portions
of the sacrum, as if strained or bruised. Clusters of small miliary
pimples at the bend of the elbow, with redness around the pimples after
scratching them. The pimples cease to be vesicular; other pimples appear
on the insteps. Prickling sensation in the eyes all day, with redness
and smarting at the border of the lids. 95. Sensation as if there were
dust or foreign bodies in the eyes. The right eye is more sensible than
the left. Weariness in the legs, after noon. Pain in the left knee as
from a sprain, with lancinations below the pain.
_Fourteenth day._—Contractive sensation below, and at the right side
of the coccyx. 100. Rheumatic pain at the left side of the neck, the
splenius, complexus and trapezoides muscles.
_Fifteenth day._—Rheumatic pain at the neck, with difficulty of turning
the head to the left side, in the morning. Pain in the head like a
weight on the skull, extending to the mastoid processes. Sense of
loathing with nausea. Oppression at the stomach when standing erect.
105. Pale face, with rings around the eyes and redness at the margin of
the eyelids. Pains in the head like a beating in the sides and at the
vertex, reverberating in the mastoid processes, and extending to the
sterno-mastoid muscles. Sense of constriction in the upper part of the
throat. Yellowish, heavy and frothy expectoration, ever since he took
his drug. The affective sphere is very active. 110. Painful stiffness
of the neck, which prevents one from turning the head to the left side.
Sensation, in closing the eyes, as though the eyelids were cold. Pain
from the occiput to the vertex, with beating, and acute pains.
_Sixteenth day._—Horrid pain in the sacro-lumbar region, at the
articulation of the last lumbar vertebra and sacrum, when attempting
to raise a weight. Pain as when straining a ligament; numb pain in the
left thigh, along the course of the sciatic nerve. 115. Inability to
stoop without experiencing acute pains in the sacro-lumbar region; he
is obliged to lie down. Fainting when trying to sit down, caused by the
violence of the pain at the sacrum; sense of tearing. Nervous spasms,
convulsions, cramps in the calves and toes during the fainting spell.
Sense of shuddering at the rectum. Tickling like worms creeping along
in the rectum. 120. In spite of the pains, he slept pretty well in the
night, from the fifteenth to the sixteenth. Desire to urinate, every
half hour. He urinates a long time. Watery urine, with a greenish tint.
Cramp in the right middle, and ring-finger. 125. Pulse interrupted
for two minutes, ringing in the ears, roaring in the head, beating in
the temples. During and after the fainting-spell disposition to love
everybody, especially those around you. He often thinks of death, but
he is not afraid of dying; he even feels as though he would die without
regret. He reproaches himself with everything bad he has done, even the
least trifles, and considers himself very guilty for having done them.
During the nervous attacks, he thinks of his salvation. The sense of
smell is very acute, he even smells persons at a distance.
_Seventeenth day._—130. The pain at the sacrum seems to decrease, but he
is not yet able to rise from bed, nor stir about in it, he has to remain
lying on the back. He has an appetite, but eats little. A sort of painful
glandular swelling behind the masseter muscle, below the right ear.
Dulness of the head, in front. Sense of oppression at the forehead.
_Eighteenth day._—135. Frequent waking at night. He wakes earlier than
usual. Doughy mouth, in the morning. Foul, bloody sputa, of the color of
chocolate with milk. The pain at the sacrum is feebler, it seems to have
spread over a larger space, rises a little towards the dorsal and lumbar
muscles, and to the dorsal vertebræ. 140. The head, above the eyebrows,
is still somewhat dull. Weakness in the finger-joints and wrists. The
gland at the neck continues painful, with lancinations. Taste of blood in
the throat. Flushes of heat. 145. The breathing is painful, as if there
were a sore in the lumbar region.
_Nineteenth day._—Deep and long sleep. Nosebleed, in the morning. Pimple
at the forehead. Weight above the eyes, he is unable to read long. 150.
Sense of weariness in the arms, though lying down. The pain at the sacrum
decreases; sometimes, however, it rises again to the cervical vertebræ.
Prickling in the eyes. A cluster of pimples breaks out at the wrist, on
the external and inferior surface of the radius; they are vesicular,
(like those which he had after his return from Brazil.) Bloating
sensation in the eyes. 155. Throbbing at the sacrum, without pain. Pale
face, eyes sunken, with redness around the eyelids.
_Twentieth day._—No stool from the sixteenth to the twentieth day. Hard
and difficult stool. The pain at the sacrum is much less, though he
still feels a violent throbbing in this region, but painless. 160. Rose
at eight o’clock, his legs were weak and his head felt heavy; he laid
down again an hour after, with very cold feet. He feels a pain at the
iliac bones, though not all the time. There are fever pimples on the arm,
and the remaining pimples contain a little water which spirts out when
pressed. Sensation in the glutei muscles as if bruised. Full and slow
painless beatings in the sacro-lumbar region.
_Twenty-first day._—165. Restless night, dreams about crime, dead bodies,
children with their heads half cut off, and of others whose heads were
being cut. Pain in the glutei muscles as if bruised, now on the right,
then on the left side. Pain as if bruised at the sacrum, with heat
mounting to the face, at nine o’clock in the morning, shortly after
rising. Cramp in the toes. Beatings in the left temple. 170. Painful
stitch and beating sensation between the shoulder-blades.
_Twenty-second day._—Lascivious dream with emission. Heat mounting to the
face, with oppression of the chest. Acute pain in one of the right toes.
Weight at the sacrum, but less bruising in the glutei muscles; weakness
in the knee joints, with cracking, either in going up or down-stairs,
175. Sensation as if a warm liquid were flowing from a sore in the lumbar
region. Heat mounting to the face, at seven o’clock in the evening.
Weakness of the legs in going up or down-stairs.
_Twenty-third day._—Restless night, heat and sweat all night. Dream about
work, vast business. 180. Dizziness at two o’clock, waves before the
eyes; the sight becomes dim when writing. Sparks and zig-zag movements
before the eyes, when walking or sitting. Weak legs. Weight in the upper
lids. Frontal headache. 185. Pressure at the forehead, with damp coldness
at the feet and hands. The headache extends to eyebrows and eyes.
Short-lasting oppression at the throat, in the region of the tonsils. The
eyes are red, with blue dark margins; face pale, yellow, dull. Less pain
in the renal region; but he is unable to stand any length of time without
experiencing an uneasiness in the stomach which extends to the chest with
oppression. 190. Sclerotica red, inflamed, and the capillaries injected.
Beating pressure at the sclerotica. Weakness of the knee-joint, when
walking or going up and down-stairs. Hiccough four hours after eating.
_Twenty-fourth day._—Restless sleep. 195. Slight prickling pain at the
sacro-lumbar articulation, in going up-stairs. Sense of oppression at the
chest.
_Twenty-fifth day._—Pressure at the forehead. Heat in the sacro-lumbar
region; sense of oppression at the chest, and rush of blood to the
larynx, with suffocative oppression; taste of blood and tearing in the
chest.
_Twenty-sixth day._—Restless sleep. 200. Throbbing and weakness in the
sacro-lumbar region. Nausea while riding in a carriage, before breakfast.
Sense of heat in the renal region, after a long ride in a carriage.
Slight aching pain at the forehead and vertex.
_Twenty-seventh day._—Restless sleep. 205. Beatings in the lumbar region,
with slight pullings or shudderings. Weakness in the lumbar region.
Weakness in the knee-joint; sense as if sprained, after a walk.
_Twenty-eighth day._—Restless sleep, with dreams about work, wild beast
devouring meat in a public slaughter-house. Sense of heat with throbbing
and fatigue in the lumbar region and above the iliac bones. 210.
Paleness, cold hands and feet, with weakness all over while the pains
last.
_Twenty-ninth day._—Dream about revolution, gun-shots, demolition of
some public edifice; he walked among the ruins. Sense of well-being, in
the morning on rising. Doughy mouth every morning, with sputa that has
the color of chocolate with cream, and fœtid smell. Spits blood in the
morning that seems to come deep out of the throat. 215. Swelling of the
left lower gums, over the molar teeth, outside, with toothache in this
region. Small pimples on the right knee, with smarting as from a tetter
and painful itching when touching them; they emit a fluid when pressed
upon; itching at the tibiæ.
_Thirtieth day._—The swelling of the gums continues, but the toothache
is less. The cheek threatens to swell. Taste of blood in the mouth and
throat, very marked, with scratching or tearing sensation when drawing
breath. 220. Headache at two o’clock, as from a nail in the vertex, with
violent toothache, swelling of the gums, after a walk. Beatings in the
left side of the face, extending up to the eye. The feet, and mostly the
whole body are constantly damp and cold, with weakness. Uneasiness at the
stomach. His breakfast does not seem to sit well on his stomach; he eats
with a good appetite, however (from the twenty-fourth day).
_Thirty-first day._—Restless night. Intolerable erections, sexual dreams,
with emissions. 225. Large pimples on the legs, around the root of each
hair. In the evening, large pimples, swollen, like mosquito-bites, with
violent itching, and raw feeling when touched.
_Thirty-second day._—Weakness, with painful stitch in the lumbar region.
Uneasiness in the stomach, every day after the noon-meal. Violent
headache on the left side.
_Thirty-third day._—230. Sense of tearing and spraining in back when
sitting (for one minute). Spitting of blood, with sense of rawness in the
throat and the respiratory passages, after talking. Contractive sensation
on the skin of the forehead. Pimples all over the body, similar to those
above described; suffocative sensation rising to the larynx.
_Thirty-fourth day._—Taste of blood in the mouth during an embrace. 235.
General emaciation. Inability to incline forward; he can only walk by
reclining the trunk backwards; when inclining forward ever so little, he
feels a pulling in the lumbar region and is obliged to straighten himself.
_Thirty-fifth day._—Uneasiness at the stomach from the noon-meal until
four in the afternoon. Irritable mood.
_Thirty-eighth day._—Frequent desire to urinate. 240. Clear urine, after
a return of the pain in the sacro-lumbar region. Tearing sensation in the
renal region; acute pain, with faint feeling and pale face.
_Forty-sixth day._—Cold sweat at night.
_Fifty-fifth day._—Pale, sickly face; rings around the eyes. Red lips.
245. Emaciation. Weakness in the sacro-lumbar region. Dimness of sight,
and prickling in the eyelids. (From this period, he gradually gets
better.)
Second prover: Chr. Dieudonné Joly, twenty-four years old,
sanguine-nervous temperament, robust constitution.
At eight o’clock in the evening, took one dose of assacù of the fifth
attenuation.
_First day._—Contraction of the papillæ on the tongue, immediately. 250.
Heaviness of the head. Acute pain in the right kidney while walking, with
urging to urinate, at nine o’clock in the evening; for two minutes.
_Second day._—In the morning, while walking, pain as if sprained in the
left coxo-femoral articulation, for some moments. Prickling at the margin
of the eyelids, in the day-time. Face looks weary, with rings around the
eyes. 255. Lancinations in the left index and thumb. Dull lancinations in
the right hand. Itching at the left side and calf. Stitch in the right
index-finger at eight o’clock in the evening. Feeling as of sand in the
left eye, at ten o’clock.
_Third day._—260. Nocturnal emission. Sneezing at noon, as when a
catarrh is about setting in. At two o’clock, dark redness and almost
complete insensibility of the sides of the neck in the region of the
sterno-cleido-mastoideus-muscles; he pricks the parts and does not feel
any pain until one hour after.
_Fourth day._—No sleep at night, and drowsy in the day-time. Livid
complexion at noon. 265. At nine o’clock in the evening, itching at the
left eyelids.
_Fifth day._—Violent nosebleed, at seven o’clock in the morning. Stinging
in the ball of the right thumb. Slight pain in the medius of the left
hand.
_Sixth day._—Itching at the margin of the left eyelids. 270. At noon,
pimple at the right lower part of the lower jaw. At ten o’clock in the
evening, in bed, smarting and itching of the puncta lachrymalis and the
left lower eyelid.
_Seventh day._—At two o’clock: Aching pain like a stitch in the side,
under the right lower ribs, for one minute.
_Tenth day._—At three o’clock in the afternoon, slight colic, and nausea.
Dull and heavy head, with weak legs.
_Eleventh day._—275. At eleven o’clock, hypochondria, sadness, despair;
he imagines that he is abandoned by his family.
_Twelfth day._—Fatigue, and weakness of sight.
_Thirteenth day._—Eyes red, with weak sight, he reads with difficulty.
The upper and lower limbs feel weak.
_Fourteenth day._—Eyes weary, sight weak. 280. Short, dull, painful
lancinations in the pectoral muscles, rather internal, without impeding
the breathing.
_Fifteenth day._—Weariness of the eyes, pressure at the superior portion
of the orbits. Headache. At nine o’clock in the evening, lancinating pain
in the biceps and triceps muscles of the arm, similar pain between the
shoulder-blade and the spinal column, in the trapezoid muscle. The throat
feels dry and irritated, compelling one to cough. 285. Dryness of the
glottis; causing a cough as from a cold.
_Sixteenth day._—Itching at the margin of the eyelids.
_Seventeenth day._—Sense of stoppage in the ears; afterwards as if
air-bubbles were passing through the left ear (for two or three seconds).
Small smarting pimples on the lower part of the right leg.
_Twenty-third day._—Diarrhœa.
_Twenty-seventh day._—290. Nocturnal emission. Weight at the frontal
muscle. Heat about the head. Painful stitch in the ileo-cœcal region,
recurring several times when walking or moving about. Slight nausea.
_Thirtieth day._—295. Pain as from weariness in the outer portion of the
left crural muscle when pressing upon it.
_Thirty-first day._—This pain is very marked and continues all day.
_Thirty-second day._—Violent headache in the left side of the head.
_Thirty-third day._—Headache in the side of the head.
_Thirty-fourth day._—In the evening, slight pain in the lumbar muscles as
from weariness.
_Thirty-fifth day._—300. The weariness in the loins continues in the
morning. At 9 o’clock in the evening, slight pain as from weariness, with
an acute lancination in the lumbar region, for one second.
_Thirty-sixth day._—At noon, long-lasting lancinating pain under the left
big toe. A good appetite for some days past.
_Thirty-seventh day._—305. Hard, scanty and difficult stool. Absence
of mind. Not disposed to work. Peevish. Red eyelids. 310. Lazy, weary.
Constant yawning.
_Thirty-eighth day._—Hungry, two hours after a copious meal. Tightness at
the stomach, in the evening.
_Thirty-ninth day._—At five o’clock in the morning, violent sensation
of hunger, with tensive and pressive pain at the stomach; when lying,
the pain extends to the umbilical region. 315. The pain during a walk
continues; pressure after eating; painful sensation of hunger. Acute pain
at the stomach, with constant hunger. Frequent desire to urinate. The
urine deposits a white sediment. At noon, pressive pain at the stomach,
before and after eating. 320. Acute pain, like a stitch, at the anterior
surface of the right lung, which hinders breathing. Absence of mind, he
makes many mistakes, mistakes one month for another, for several days. He
mistakes the street twice. During the last days of the proving, frequent
urination with whitish deposit.
Third prover: Mme. Al. j., 26 years old, sanguine temperament, good
constitution.
_First day._—Took one dose of the 5th attenuation, at 10 o’clock in the
evening.
In the morning on waking, doughy taste in the mouth, and great
drowsiness. 325. She dreams about death, burial. Small painful pimples
on the left side of the tongue. Burning at the stomach. Stiffness at the
nape of the neck. Weakness of the legs and arms. 330. Nausea at two
o’clock. Fever: face of a scarlet-red, hands burning-hot. Depression of
spirits, has no desire to do any thing, nothing pleases him. White spots
on the tongue. Frequent desire to urinate. 335. Feeling of weariness all
over. Sense of pain with heat at the sacrum.
_Second day._—Lancinating pain, zig-zag, in the uterus, at half past six
in the morning. Slight leucorrhœa. Dry cough. 340. Pain in the groin,
compressive sensation as during parturition. Lancination from the lumbar
region to the coccyx.
_Third day._—Restless night, frequent waking. On waking, sense of
weariness, as if strained. Acute pain in the palm of the left hand,
proceeding from the index, and describing a circle extending to the
carpal articulation of the thumb. 345. Very weary, especially the left
leg. At half past 12, third night, writhing colic. Violent diarrhœa
at one o’clock, with pains similar to those which she had experienced
on her return from a voyage to Brazil. Fetid stool, with white little
worms. 350. The diarrhœa continues and is succeeded by a great weakness
of the chest. Violet-colored cheeks. Heat in the cheeks and temples. Red
forehead. Small miliary vesicles on the right cheek, on the middle of the
forehead and on the left cheek. 355. Listless, she attends to things as
if she took no sort of interest in them.
_Fifth day._—Dreams about a church-yard; she placed torches on the
graves. On waking, her face is bloated and scarlet-red. Blotches on the
right cheek, similar to those which she had after her return from a
voyage to Brazil (at this time an enormous crusty tetter commenced in
this way). Intolerable heat at the chest, at two o’clock, violent pain
and burning sensation at the sternum.
_Sixth day._—360. Restless sleep. Nervousness, impatience, at half past
12. Dry heat in the hands.
_Seventh day._—Small vesicular pimple at the right wrist-joint. Marked
feeling of heaviness from the parietal bone to the lower attachment of
the sterno-mastoideus muscle, at the upper side of the sternum. 365. At
two o’clock: the weight, at times, descends to the forehead, with heat.
Small pimple on the right wrist, red at its base, containing a fluid.
_Eighth day._—No sleep. Twisting pain in the left side, or lancinations
around the pelvis; the pain passes off soon and extorts cries from her,
at 9 o’clock in the morning. Burning all over.
_Ninth day._—370. Twisting pain at the scapulo-humeral articulation.
Acute pain under the breast. Half past twelve: the pain at the
scapulo-humeral articulation recurs from time to time with great
violence. Five o’clock in the evening: the pain is constant but less,
always of the same kind. Half past nine: miliary eruption in the face.
375. Small red pimples on the right cheek, smarting on the right cheek,
the eruption first showed itself at 7 o’clock in the morning. Miliary
eruption on the shoulders, with itching, in the evening. Red vesicular
pimples, they break when pressed upon, and discharge a smart stream of
water.
_Tenth day._—Dulness of the head, in the morning, on rising. Red face,
the little pimples are less apparent. 380. Pain at the stomach, as from
hunger, though she is not hungry. She swallows her saliva. She has to eat
to quiet her pain.
_Eleventh day._—Headache, slight beating at the forehead, during a
considerable portion of the night. The headache continues with a
heaviness in the forehead, in the morning.
_Twelfth day._—385. Small pimples on the back, with itching. Nosebleed,
at 8 o’clock. Hard stool for 8 days. Nosebleed, at 10 o’clock.
_Thirteenth day._—390. Restless night, dream about a sea-voyage.
Heaviness of the head, nosebleed on rising. Headache, heaviness with
beating in the forehead, all day. Red pimples on the shoulders, with
pricking when touched. Lancination and pricking in the left little
finger, three or four different times.
_Fourteenth day._—395. Hot and red face. Itching red pimples on the
shoulders.
_Fifteenth day._—Sense as of crumbs in the eyes. Sclerotica red, with
margins around the eyes, red eyelids, red face. Red pimples on the sides
of the hips, smarting.
_Sixteenth day._—400. Sharp pain, followed by an acute lancinating pain
about the heart.
_Seventeenth day._—At eight o’clock in the morning, sharp, lancinating
pain, by fits and starts, at the right side of the sacrum, more or less
violent. Ten o’clock in the evening: wry neck on the right side.
_Eighteenth day._—While slumbering, sensation as if she were hanging
three feet from the ground. Sensation as if she would fall into a ditch.
405. Coldness and heat, alternating at night.
_Nineteenth day._—Acute pain at the left hip, at 9 o’clock in the
morning. The pain recurs at 9 o’clock in the evening, and continues for
several days at the same hour. Pain at the uterus as if compressed. Pain
at the heart, which is at times very sharp, almost unbearable. 410. The
breathing is arrested; this pain makes her very uneasy. Lancinating pain
in the head.
_Twentieth day._—Pain at the left knee, as if sprained.
_Twenty-first day._—Writhing colic, and diarrhœa, five times in the day.
_Twenty-second day._—Restless night. 415. In the evening, pain at the
loins and on each side of the ovary. Violent lancinations with prickling,
afterwards lancinating pain in the vagina; appearance of the menses, but
very slight.
_Twenty-third day._—Pain in the uterus as if a sharp instrument were
thrust in. Lancinating pain above the left breast. Pain at the right
little toe, like an intermittent throbbing, with intolerable prickling,
at half past 10 o’clock in the evening.
_Twenty-fourth day._—420. Sleep disturbed by a violent itching caused by
small pimples on the shoulders. In the morning, the pain of the little
toe returns, but it does not last as long as the day previous. Pain in
the renal region, with sense of weariness in the region of the sacrum.
Cold and heavy pain at the left hip. Painful pricking in the wrist and
along the left hand, between the middle and ring-finger.
_Twenty-fifth day._—425. Prickings and stitch above the left breast,
hindering breathing, whether walking or sitting. Acute pain when drawing
breath.
_Twenty-sixth day._—Sense as if sprained in the left knee and cracking
when walking.
_Twenty-eighth day._—Restless night. Desire to cry. 430. Fever, inability
to close her hand. Sad, vexing thoughts.
_Twenty-ninth day._—Sensation as if floating in the air. No sleep.
Starting in bed. 435. Sensation as if she were falling to the ground.
Lancinating pain under the heart; it continues, more or less feeble. Bad
digestion, the stomach feels yet full since supper.
_Thirtieth day._—Restless night, starting during sleep. Sense of
weariness in the lumbar region, all night. 440. Pain at the sacrum
as from a recent blow, this pain increases until four o’clock in the
evening. Pressure at the sacrum, with weariness in the left thigh.
Heaviness at the sacrum, when sitting. Sensation as if worms were
crawling in the posterior and external portion of the sacrum.
_Thirty-first day._—The pain at the sacrum obliges her to keep bent;
this pain shifts up and down from the sacrum to the left thigh, and is
accompanied by chattering of the teeth, which interrupts the speech, and
by cold hands and feet. 445. Quickly-passing tingling and twisting pain
in the right leg, at three o’clock in the evening, when lying. Twisting
pain extending from the sacrum into the left leg, and obliging her to lie
down. Every paroxysm of pain excites a nervous laugh, with moanings like
those of a sick child. Sensation as if dogs had bitten her where the pain
is felt. Sensation as if she had a plaster at the region of the kidneys.
450. The pain descends along the vastus externus muscle. Mottled face,
in the beginning of the proving it became red, now it is sometimes pale.
She cannot walk, without fearing to fall. No solicitude for the future,
generally speaking; tears with ennui; she thinks of death without fearing
it. The pain at the sacrum is worse when sitting, and obliges her to lie
down.
_Thirty-second day._—455. Sleep during the night, but the pain in the
renal region returns as soon as she rises from bed. The pain is seated
in the sacro-lumbar articulation; it extends to the glutei muscles with
sensation as though she were gnawed by dogs. At times the right thumb
feels numb.
_Thirty-third day._—Pain in the vertebral column. Sense of luxation, with
pain in the glutei muscles, of the same nature as the day previous.
_Thirty-fourth day._—460. Twisting sensation in the groin. Nosebleed,
when lying. Vesicular pimples all over, with red spots as if the skin had
been rubbed. Large blotches on the legs like mosquito-bites. Sensation
in the renal region and buttocks as if gnawed by dogs. 465. Continual
sneezing for two hours.
_Thirty-seventh day._—Sensation in the thighs, as if bitten by dogs. The
pimples increase during an increase of temperature, and leave large red
spots in the renal region and on the hips. Since she had the pains in the
sacrum, she is unable to sleep or rest on the stomach.
_Thirty-eighth day._—Uneasiness, sometimes she cries in the street. 470.
Acute headache, like a circle which rolls quickly over the forehead.
Dizziness. Profuse nosebleed from both nostrils. The nosebleed is
preceded by a smell of blood. Red face, with little pimples between the
skin and flesh. 475. Heat at the face. Sensation as if the skin of the
face were stretched too much. Frequent emission of watery urine. Sense of
coldness in the right-thigh.
_Fortieth day._—480. Dreams about dead bodies, assassins, decayed oxen,
yellow water. Continual nosebleed, especially in the morning. The pains
in the renal region decrease.
_Forty-third day._—Nervous twitching at the left lower eyelid.
_Forty-fifth day._—Flow of sad thoughts; she imagines she will lose
somebody who is dear to her. 485. She cries every moment, and, for
several days past imagines she is seeing the dead person before her eyes.
_Fifty-eighth day._—Painful sensibility of the whole right half of the
head, especially when touching it. Lancinations in the jaws, pain at the
right arm. Impatience, anger; she bites her hands, and gets mad because
her ideas flow too slowly.
Fourth prover: Mlle E. R. 17 years, sanguine temperament, good
constitution. 490. At 8 o’clock in the morning, the ball of the thumb of
each hand is painful. 9 o’clock: her feelings are excited and she cries
a good deal. 10 o’clock: numbness of the right index, every minute. Half
past 10: cold and clammy feet, followed by heat for three hours. Half
past 11: short lancinations in the last two left molares, lower jaw;
numbness in the bend of the right arm. 495. Lancination in the right
index-finger, and especially in the articulation of the last phalanx.
Sensation of a small ball under the left breast; at the same time,
lancination under the left shoulder, for 5 minutes. At noon, large red
spot on the lower part of the left cheek. Half past 12: heat at the face,
for half an hour. Half past 12: small pimples on the left cheek, above
the nose and near the lower lip; they are red, with a small white point
in the middle. 500. At two o’clock, beating in the right index-finger.
At half past 2, lancination in the gums. At a quarter past four; pain in
the gums corresponding to the left eye, with heat in the face. Burning in
the left cheek, weight at the eyes, lancinating pains in the ears. Pain
at the outer ankle, as from a blow. 505. Frontal headache, at half past 9
in the evening. Cold sweat on the face. Pressure in the orbits, as from a
violent headache. The teeth and gums are painful when pressing the teeth
against each other; the pain extends to the nose. Toothache on the left
side.
_Second day._—510. Half past seven, white-coated tongue. Slight pain
shifting from the left ear, where it commenced, to the left orbit.
Small pimple at the inside of the left elbow, causing a smart itching.
Half past 7, lancinations in the right side, every second. Cold feet.
515. Eight o’clock, pain as if the right arm had been stretched a long
time, contusive pain at the back of the right hand, especially at the
middle-finger. Lancinations in the gums on the right side. Itching at
the forehead. Small pimples at the forehead. Suffocative oppression
in the chest, especially when thinking of any thing contrary. 520. The
oppression ascends and immediately after descends again. Heat mounting to
the face. Pain at the sternum. Lancinations in the temples. Pain in the
gums on the left side. 525. Discouraged, does not wish to do any thing.
Weight at the arms. Suffocative oppression in the chest. Ten o’clock in
the evening, pain in the orbits as from a violent headache, or as from
looking fixedly at the same object.
_Third day._—Half past 6 in the morning, the right cheek is quite
swollen, without toothache. 530. Red pimple on the left cheek, in the
middle, and on the left side of the neck, with a good deal of itching.
Nine o’clock, beating at the right side of the thorax, almost under
the shoulder. Half past 3, pain at the right wrist; all the veins and
fibres hurt her. Half past 8, oppression at the stomach. Twisting colic.
535. Nine o’clock, heat at the face. Half past 10, desire to cry. Since
taking the drug, the least thing irritates her; at such times she feels
oppressed, with desire to cry, she blushes, sighs a good deal, several
times a day. Less appetite. Pain at the chest, especially the left
breast, when lying; the pain gradually passes to the right side.
_Fourth day._—540. Since the first day, she wakes sooner than previously;
her sleep was heavy and she was unable to open her eyes. Now she opens
them easily, and the ideas come to her at once. Half past 5, shuddering
all over, she feels oppressed, wants to cry. Colic, with cold feet. Eight
o’clock, the shuddering extends over the legs; she feels oppressed and
has cold feet. 545. Nine o’clock, prickling at the tongue on the left
side, causing a good deal of water to accumulate in her mouth. Nervous
pain shifting speedily from the orbits to the forehead, and disappearing
at once. She sighs a good deal. Ten o’clock, she feels sick at the
stomach, as from hunger, generally she is not hungry till noon. Hungry,
sometimes shortly after a meal. 550. Pain as from pressing strongly on a
sore behind the right ear, and under the neck, at the larynx; pain when
moving the head. Cold feet, at 10 o’clock in the morning. Hunger, with
pain in the stomach, at 11 o’clock. Tightness at the root of the nose,
for an instant. Short lancinations all over the face, with tightness of
the head emanating from the temples. 555. Slight contusive pain under the
false right ribs.
_Fifth day._—At noon, oppression hindering breathing. Oppression in the
chest, causing her to sigh a good deal. Numbness of the head. The face,
and head, from the vertex, pain her horribly. 560. Contusive pain between
the ring- and little finger, only for a moment; reaching up to the elbow.
Tightness at the back of the head. Pain as from weariness in front of and
behind the neck. Frequent desire to urinate. The left cheek is very red.
565. Redness of the wing of the nose. Shuddering along the back and legs
while taking breakfast. At 5 o’clock, oppression and sighs. Pain in the
ear, and half of the jaw, followed by pricking in the ear. At a quarter
past 5 o’clock, colic and shuddering. 570. At 8 o’clock, pain as from
weariness between the shoulders. At 9 o’clock, oppression on the chest.
She sighs a good deal. Internal trembling. Cold sweat on the feet. 575.
At half past 10, red blotch on the right shoulder; hot feet, after lying
down, in bed.
_Sixth day._—At 6 o’clock, colic, with diarrhœa and internal trembling.
Shuddering at half past 6. Red spot and itching at the forearm. At 7
o’clock, colic with diarrhœa and shuddering. 580. Nervous laughter
which causes her to shudder. Cold feet, shuddering in the left leg.
At 8 o’clock, cracking in the right forearm. Lancination in the left
gums, reaching to the right ear. At a quarter past 8, red spot like a
flea bite, on the back of the left hand. 585. Dulness of the head, with
weight at the orbits. Cold feet, especially the left. At 9 o’clock,
oppression on the chest, with sighing. At 11 o’clock, weight at the
orbits, as from sleep. Crampy pain at the right wrist, shifting to
the arm and then to the axilla. 590. Colic at the stomach. Oppression
and sighing. Trembling of the right arm, and beating at the anterior
surface of the wrist. At a quarter past 11, rheumatic pain at the right
shoulder. Small vesicular pimples on the lower lip, itching a good
deal. 595. Pain as from having been lying in a wrong position, under
the arm, under the right sight side of the chest. Painful beating above
the right breast. Painful lancinations in the head, striking to the ear
and the left teeth, and then shifting to the upper part of the orbit.
Drowsy at noon. Pain between the shoulders, worse by pressing against the
sternum. 600. Contusive pain at the left leg. Painful stitch at the outer
breast, extending under the arm. Hungry, but satiated at once. Itching
at the right outer ankle. Numbness of the right arm, as far as the left
index-finger, all the muscles hurt him. 605. At one o’clock, formication
in the soles of the feet. At half past one, contusive pain in the back,
at the hips and in the renal region. Strong pressure at the left temple.
Drowsy at 2 o’clock. Colic at half past 3. 610. At 4, beating at the
outer side of the right wrist. Nervous shuddering all through the chest,
and passing between the shoulders. Lancination from the left side of the
head to the eye, temples, above the ear and in the lower jaw. Whizzing
in the ears. Pain at the stomach as from hunger. 615. Lancination in the
left breast. Lancination in the first phalanx of the middle-finger. At
4, toothache on the left side, affecting the eyes. Violent pain in the
back as if weary, and affecting the lumbar region. Pain at the stomach,
oppression, sighs. 620. Lancination in the left gums. At 4, beating in
the right external ankle. Lancination in the whole jaw. Redness, and heat
mounting to the face; cheeks and forehead are redder than the rest of the
face. At half past 8, oppression, pain at the stomach, as from hunger.
_Seventh day._—625. At 6, colic, diarrhœa and shuddering. At 8, merry,
with desire to laugh, followed by shuddering in the head and legs.
Cold feet. Lancination in the left lower gums, tightness of the nose,
felt even in the jaw. Feelings excited, oppressed, as from some great
misfortune. 630. Nervous pain below the bend of the right elbow,
descending to the ring- and little fingers, at 10 in the morning. Painful
pressure on the left shoulder, which is very sensitive, at 11 in the
morning. Beating at the right shoulder. At 11, lancination in the gums
and left eye. Stiff neck, the least motion causes a pain in the nape of
the neck and gums. 635. Weight at the eyes and in the head. Numbness at
the nape of the neck. Sensation as of a bar through the jaws, from ear
to ear, with tightness of the head. Tightness at the root of the nose.
640. The teeth are painful when chewing. Pain in the back, under the
right shoulder, accompanied by beatings in the chest. Cold feet at one
o’clock. Beatings in the right side of the chest. Heat in the face and
drowsy after dinner. 645. Weight at the orbits. Pain in the side, with
lancinations in the right breast. Pain in the bend of the right elbow,
worse when moving it. Beating at the lip of the right index-finger.
Suffocative oppression, causing her to sigh a good deal. 650. Colic,
yawning. Beatings at the tip of the tongue, on the left side. At half
past 2, pain in the renal region when sitting. Heat and pain in all the
toes. Numb pain from the wrist to the upper part of the right arm. 655.
Stiffness and beating in the left side of the neck, especially when
moving the head. At half past 8 in the evening, beating in the right
orbit, afterwards in the sides. Beating at the root of the nose. Painful
stitches in the right side, hindering breathing. At a quarter past 10,
aching and contusive pain in the right side. 660. Pain as from weariness
below the right shoulder. Head heavy and dull, the least motion affects
her eyes and the region of the orbits. Lancinations in the gums and heat
in the face.
_Eighth day._—At 6, colic and diarrhœa. Lancination in the left breast,
at 2 in the evening. 665. Pain in the right renal region. At noon, pimple
on the forehead, left side. At 2, heat in the face. At 4, beating in the
right, and sometimes left orbit. At 6, painful stitch in the right side,
hindering breathing. 670. At 7, sadness, desire to weep. Rush of blood
to the head. Heat in the face. At 10, nosebleed. At 11, cold and clammy
feet, while lying down. 675. Hot feet, some time after.
_Ninth day._—At 6, pain in the right thigh, high up, at the outer side,
causing her to limp. Painful stitch in the left breast. At half past 7,
desire to weep, oppression as from some emotion. At half past 8, desire
to weep, the least trifle makes her sad; she starts when hearing a
door opened suddenly. 680. She is oppressed and breathes heavily. Pain
in the right wrist, striking to each finger. Hot face. Great desire to
weep, even while singing, followed by oppression, at half past 9 in the
morning; she weeps. Acute nervous pain from the shoulder to the left
breast. 685. Pain at the bend of the right elbow. Heaviness in the eyes
and desire to sleep, at a quarter of one. Beating in the left side of the
abdomen. Beating in the pit of the stomach, reverberating in the whole
chest. Frequent ineffectual urging to stool. 690. Tight pain above the
ears, with numbness of the jaw. Heaviness in the whole head. Lancination
in the left lower gums; shortly after, lancination in the upper gums.
Stiffness of the nape of the neck. Hot face. 695. Loud whizzing in the
left ear. Drowsy. Numbness of the gums. Deep sighing, yawning. Mounting
of heat to the face, now and then. 700. Pain in the left gums striking
to the eye and behind the ear. At one o’clock, heat, no appetite.
Lancinations in the gums, reverberating in the whole head. Violent
beating at the left temple. Numbness of the left wrist, the whole hand
is painful. 705. Acute pain in the left gums, the whole left side of the
head is numb. Warm hands and cold sweat, at 3 in the afternoon.
_Tenth day._—Torpor of the head, with numbness in the upper gums and the
muscles of the eye. Pain at the right hip, at one o’clock. Tightness
at the epigastrium; her feelings are very much excited, as if some
misfortune should happen to her, at 2 in the afternoon. 710. Pain in the
right ear. Pain in the left cheek and gums. Beating in the arm and right
wrist. Weight at the right orbit, at 3. Little appetite. 715. Cold sweat
in the face, at half past 6. Suffocative oppression. Drowsy, at half past
8. Hot face, at 9.
_Eleventh day._—Restless sleep. 720. Doughy mouth, at 6 in the morning.
Inflammation of the left puncta lacrymalis. Pain at the right gums and
cheek, at noon. Burning of the cheeks, from one to four.
_Twelfth day._—Small pimples in the face, at 6 in the morning. 725.
Pain in the renal regions, at 9. Weakness of the legs. Beating under
the right hip. Pain at the gums, at 11. At 2 in the afternoon, pain and
beating under the left shoulder. 730. At 8, small pimples on the chin,
itching a good deal. At half past 8 in the evening, colic and cold sweat.
_Thirteenth day._—Eyes bloated, surrounded by margins. Colic and
diarrhœa. Uneasiness when lying down. 735. Leucorrhœa. The period sets in
8 days before its time. Profuse menses. At half past 6, lancination in
the left gums. At 7, lancinations in the jaw. 740. Tightness at the root
of the nose. Numbness of the right arm. At 9, whizzing in the right ear.
Pain and beating on the right shoulder. At 10, beating in the left little
finger, thumb and index-finger. 745. Burning at the whole hand. Violent
itching at the index-finger, the whole of the left arm is painful,
especially the wrist joint. At half past 10, beating pain near the right
internal ankle. Hot feet. Toothache, on the left side. 750. At 11, pain
and itching at the left foot, violent pain in the whole of the right
foot. Violent pain near the inner canthus of the left eye. Pain in the
left wrist-joint. Beating in the right index-finger. At noon, bloating of
the lower eyelids. 755. Redness on the left side of the nose. Pain in the
wrist and bend of the left arm. Contusive pain at the right knee. Pain in
the left gums. Pain in the legs as from weariness. 760. At 2, lancinating
pain shifting from the knees to the right elbow, then to the shoulder,
to the right foot, right wrist, and lastly to the knees. At half past
2, nervous pain in the renal region. Pain behind and in the right ear.
Colic. Pain in the left gums, striking to the root of the nose. 765.
Pain in the left wrist. Pain as from weariness in the back, near the
left shoulder. Whizzing in the right ear. Pain as if her arm were pulled
violently. Painful stiffness in the left side of the neck.
_Fourteenth day._—770. At half past 6, pain in the wrist. Pain behind the
head and in the neck, reverberating in the left gums. Stiff neck. Pain
and beating in the elbow, at the right forearm and in the bend of the
left elbow. Rheumatic pain in the right shoulder, passing under the arm.
775. Painful stitch in the left breast. At noon, the left foot burns,
the right foot is cold. Heat and pain at the right index-finger. At half
past one, heat at the feet, especially the right foot. Pain at the right
little toe. 780. At 2, pain at the tip of the tongue. At 10, pain in the
left gums.
_Fifteenth day._—At 10 in the morning, pain at the gums. Suffocative
oppression of the chest. At 9 in the evening, nervous trembling of the
right arm.
_Sixteenth day._—785. At noon, beating at the right middle and
index-finger.
_Seventeenth day._—Dreams about purchases. At half past 9, pain at the
right arm, shifting to the little finger. Pain at the left breast, almost
under the shoulder. Numbness of the right wrist. 790. Beating at the
right shoulder. Lancination in the left gums. At half past 10, pain in
the whole right hand. Pain in the right orbit. Pain at the left wrist and
in the whole hand. 795. Pain in extending the left arm. At noon, nervous
shuddering. Burning pain with red spot above the right elbow. Nervous
pain shifting from the eye to the gums, with beating at the left temple.
Violent beating in the left side of the thorax, under the shoulder. 800.
Heaviness at the left orbit. Lancinations in the right wrist and thumb.
Drowsy, at 2. Numbness of the arm. At 3, pain in the back and chest. 805.
Beating at the right temple. Violent pain like a stitch, in the left
breast. At 2, slight itching at the knee, below the lower lip, changing
to an acute pain when rubbed, which lasts all day.
_Eighteenth day._—Dreams about mutilated bodies, dead bodies, with the
arms cut off. At half past 6, pain under the lower lip, with swelling on
the left side, and a large red pimple in the centre of the swelling. 810.
At 8, pain and prickling at the right shoulder. Beating above the right
knee. At 5, cold feet, hot face.
_Nineteenth day._—Dreams about children, prisoners being set free. At
half past 8, cold feet. 815. At 3, pain in the orbits and forehead. At
half past 4, pain at the gums passing to the left eye. Pain at the right
wrist, between the thumb and index-finger, also near the bend of the
arm. Nervous beating in the left orbit. The skin on the forehead feels
stretched. 820. Impatient; she wants to break every thing. Absence of
mind at work. She imagines she is alone in the world and lost. Weeping
without cause, followed by nervous laugh. Sad, melancholy; she thinks of
the future, feels unhappy.
_Twentieth day._—825. At one o’clock in the afternoon, sickness at the
stomach after eating. Hemicrania, pains all through the head. Drowsy,
with nausea. Tightness of the back part of the head. Sharp pain behind
the ears. 830. The least thing hurts her, causing horrible pains in the
forehead, temples and under the chin. Lancination behind the neck, on the
left side. Beating in the left breast. Cold feet. At 5, shuddering all
the time. 835. Headache when walking. Horrible pain and beating in the
chest. Involuntary closing of the eyelids. Pain in the gums. Internal
trembling. 840. Rush of blood to the head; she turns red.
_Twenty-first day._—From the 11th to the 21st day, profuse menses with
leucorrhœa. At half past 2, pain and beating in the left shoulder. At 3,
beating in the left side of the head. Drowsy: heaviness of the head.
_Twenty-second day._—845. No sleep. Colic with diarrhœa, from the 18th
day. Heaviness of the head. From the 23d to the 28th day, horrible colic,
every morning, with diarrhœa, and pains in the middle of the back.
Nervous, she starts when a chair is moved with a little noise. 850. She
turns red, and her chest feels oppressed. Every day, after breakfast,
she has an attack of oppression on the chest. Difficult digestion after
breakfast; after noon she turns pale.
_Thirty-third day._—She feels hot at the hands, feet and face, though the
hands are cold and clammy to contact; she thinks this is likewise the
case with her feet and face. Cold sweat on the face and body.
_Thirty-fourth day._—855. The eyes are bloated and smaller. Painful
pimples when touched, on the left cheek and at the eyebrows.
_Thirty-fifth day._—Starting from the least noise. Yawns all the evening.
_Thirty-eighth day._—Violent pain in the chest, shifting to the left
breast, sometimes to the right, especially when moving the arm. 860.
Headache.
_Thirty-ninth day._—Pain and sense of weariness in the renal region.
Dreams about travelling and parties. Drowsy at one in the afternoon.
Hot face. 865. Coryza. Face dull and dark, with paleness, mottled with
red spots. Pain in the renal region, as from falling on the sacrum.
Copper taste in the mouth. Pain in left side hindering breathing. 870.
Inflammation of the right eye.
ARRANGEMENT OF THE SYMPTOMS ACCORDING TO HAHNEMANN.
MENTAL AND MORAL: 1. Sensation as if floating in the air. Dizziness.
She imagines she sees a dead person, and cries. Sensation as if falling
to the ground. 5. Sensation as if hanging three feet from the ground.
Listless. Absence of mind, he makes mistakes. She imagines she is alone
in the world. Laughter with shuddering. 10. Weeping, followed by a
nervous laugh. Sad, thinks of the future. Desire to weep, with oppression
and tendency to start. Merry, with desire to laugh, followed by
shuddering in the head and legs. Depression of spirits. 15. Impatience,
because her ideas flow too slowly. Impatience. Peevish. Sadness, despair,
he imagines he is abandoned. Thinks of his salvation during a paroxysm.
20. Irritable.
HEAD: Lancinating pain at the top of the head. Beating pain from the
occiput to the vertex. Pain in the head, like a weight. Headache down
to the eyebrows and eyes. 25. Contractive sensation in the skin of the
forehead. Headache as from a nail in the vertex. Aching pain at the
forehead and vertex. Headache on the left side. Semilateral headache.
30. Heat about the head. Slight beating at the forehead. Weight at the
frontal muscle. Dulness of the head, in the morning. The right half of
the head is painfully sensitive. 35. Headache as if a circle were rolling
over the forehead. Frontal headache. Dulness of the head, with weight at
the orbits. Numbness of the head. The face and head, from the vertex
pain her horribly. 40. Tightness at the back of the head. Painful darting
in the head, striking to the ear, teeth, and then shifting to the orbit.
Pressure at left temple. Heaviness of the head. Tightness of back part of
the head. 45. Rush of blood to the head. Beating in left side of head.
Headache. Hemicrania. Heaviness of the head. 50. Torpor of the head, with
numbness of the upper gums and muscles of the eye.
FACE: Weary look. Burning smarting in the beard, left side. Hot face.
Swelling below the zygoma, with sensitiveness to contact. 55. Pale face,
with sunken eyes. Beating in the left side of the face. Livid complexion.
The face looks weary. Sensation as if the skin of the face were stretched
too much. 60. Mottled face, red and pale alternately. Cold sweat in the
face. Lancinations all over the face, with tightness proceeding from the
temples. Swelling of the right cheek. The left cheek is very red. 65.
Cold sweat in the face. Mounting of heat to the face. Burning of the
cheeks.
EYES: Bloated eyes. Inflammation of the left eye. 70. Beating in left
orbit. Pain in the orbits and forehead. Heaviness at left orbit. Pain
shifting from the eye to the gums. Pain in right orbit. 75. Beating in
the orbits. Beating in the right orbit, afterwards in the sides. Nervous
pain shifting from the orbits to the forehead. Pressure in the orbits as
from a severe headache. Sensation as of crumbs in the eyes. 80. Redness
of the sclerotica, with margins around the eyes, red lids. Weariness
of the eyes, with pressure at the superior portion of the orbits. Weak
sight. Dimness of sight and prickling in the lids. Beating pressure at
the sclerotica. 85. Red eyes, with pale face. Prickling in the eyes.
Bloating in the eyes. Sense as of dust in the eyes. Violent pain near the
left inner canthus. 90. Inflammation of left puncta lachrymalis. Smarting
and itching of the puncta lachrymalis, in the evening, in bed. Burning
at right inner canthus. Involuntary closing of the eyelids. Bloating
of the lower eyelids. 95. Twitching of left lower eyelid. Itching at
the eyelids. Prickling at the margin of the eyelids, in the day-time.
Sensation of coldness in the lids when closing them. Beating in the lids.
100. Sparks and zig-zag before the eyes. Dizziness, with waves before the
eyes.
EARS: Stoppage of the ears, as if air-bubbles were passing through the
left ear. Pain shifting from the left ear to the orbit. Lancinating pains
in the ears. 105. Pain in the ear and jaw, followed by pricking in the
ear. Pain in the right ear. Tight pain above the ears, with numbness of
the jaw. Pain in the right ear. Whizzing in right ear. 110. Sharp pain
behind the ears.
NOSE: Dry nose, with itching inside. Redness on the left side of the
nose. Redness of the wing of the nose. Beating at the root of the nose.
115. Nosebleed. Tightness at the root of the nose.
TEETH: The teeth and gums are painful when pressed against each other.
Short lancinations in the last two molares. Toothache on left side,
affecting the eyes. 120. Lancination in left lower gums, with tightness
of the nose and jaw. Darting in the gums and left eye. Sensation as of
a bar through the jaws, from ear to ear. The teeth are painful when
chewing. Lancinations in the jaws. 125. Numbness of the gums. Pain in
left gums striking to the eye. Lancinations in the gums, affecting the
whole head. Acute pain in the left gums, the whole left side of the head
being numb. Pain in the right gums and cheek. 130. Pain in left gums.
Toothache on left side. Lancination in the left gums. Swelling of the
left lower gums, with toothache.
MOUTH: Beating at the tip of the tongue. 135. Pain at the tip of the
tongue. Pricking at the tongue, with flow of water. White-coated tongue.
White spots on the tongue. Contraction of the papillæ on the tongue,
immediately. 140. Pain under the lower lip, with swelling and a red
pimple in the centre of it. Fleshy growths on the inner surface of the
lips.
GASTRIC: Coppery taste in mouth. Doughy taste every morning, with
chocolate-colored sputa and fetid smell. Smoky taste of the water. 145.
Violent sensation of hunger early in the morning, with tensive and
pressive pain at the stomach. Difficult digestion after breakfast. Sick
at the stomach, after eating. Hungry, shortly before a meal. She has to
eat to quiet her pain at the stomach. 150. Hungry after a good meal.
Uneasiness after dinner, every day. Loathing and nausea.
STOMACH: Oppression at the stomach, when standing. Uneasiness in the
stomach and chest, after standing. 155. Tightness at the stomach,
evening. Burning at the stomach. Oppressive pain at the stomach, before
and after eating. Pain at the stomach, with oppression, sighs. Beating in
pit of stomach, affecting the whole chest.
ABDOMEN: 160. Pain in the renal region as from falling on the sacrum.
Pain and feeling of weariness in the renal region. Colic with diarrhœa,
also every morning. Colic and cold sweat, or diarrhœa. Pain in the renal
region. 165. Tightness at the epigastrium, with excited feelings. Beat
in left side of abdomen. Colic with diarrhœa and shuddering. Twisting
colic. Twisting sensation in the groin. 170. Pain in the renal region,
with sense of weariness in the sacrum. Sensation as of a plaster in the
region of the kidneys. Pain at the loins and on each side of the ovary.
Lancinations around the pelvis, extorting cries. Compressive pain in the
groin. 175. Painful stitch in the ileo-cœcal region, again when stirring.
Acute pain in the right kidney, while walking. Tearing sensation in
the renal region. Sense of heat in the renal region. Shuddering at the
rectum. 180. Constrictive sensation at the anus.
STOOL, URINE: Ineffectual urging to stool. Constipation. Hard stool.
Diarrhœa succeeded by weakness of the chest. 185. Fetid stool with white
little worms. Lancination in the urethra. Watery urine with a greenish
tint. Urine with white sediment. Frequent desire to urinate. 190.
Frequent emission of watery urine.
SEXUAL: Nocturnal emission. Distressing erections. Taste of blood in
the mouth, during an embrace. Weight in the testicles in walking.
195. Profuse menses with leucorrhœa. Premature and profuse menses.
Lancinating pain in the vagina. Compressive pain at the uterus.
Lancinating pain in the uterus, in zig-zag. 200. Pain in the uterus as if
a sharp instrument were thrust in. Leucorrhœa.
BRONCHIAL, CHEST: Dry cough. Constant sneezing. Dry throat, she has
to cough. 205. Suffocative sensation rising to the larynx. Sense of
constriction in the upper part of the throat. Sneezing, with discharge
of lemon-colored mucus from the nose. Pain behind the right ear and at
the larynx as from pressing on a sore. Spitting of blood, with sense
of rawness in the throat and the respiratory passages, after talking.
210. Spits blood, coming deep out of the throat. Yellowish, heavy and
frothy expectoration. Oppression of the chest, with rush of blood to
the larynx, taste of blood, and tearing in the chest. Shifting pain in
the chest. Severe pain and beating in the chest. 215. Beating in left
breast. Pain in left side, hindering breathing. Stitch-like pain in the
left breast. Suffocative oppression of the chest. Painful stitch in the
left breast. 220. Deep sighing. Pain from the shoulders to the left
breast. Oppressed and heavy breathing. Painful stitch in left breast.
Suffocative oppression, with sighing. 225. Darting in left breast. Aching
and contusive pain in the right side. Painful stitches in the right side,
hindering breathing. Lancination in left breast. Painful stitch at the
outer breast, extending under the arm. 230. Painful beating above the
right breast. Pain at the right side as if strained. Contusive pain under
the false right ribs. Sensation as of a small ball under the left breast.
Acute pain when drawing breath. 235. Stitch above the left breast,
hindering breathing. Acute pain under the breast. Stitch-like pain at the
anterior surface of right lung, hindering breathing. Pain and burning at
the sternum. Intolerable heat at the chest. 240. Painful lancinations
in the pectoral muscles. Stitch-like pain under the right lower ribs.
Rheumatic pain at the sternum when stooping. Lancinating pain under the
heart.
NECK: Painful glandular swelling below the right ear. 245. Painful
stiffness of the neck. Rheumatic pain at left side of neck. Dark
redness and numbness of the sides of the neck, even a prick is not felt.
Heaviness along the side of the neck. Wry neck on the right side. 250.
Pain as from weariness in front of, and behind the neck. Numbness at
the nape of the neck. Stiffness of the nape of the neck. Stiffness and
beating in left side of neck. Painful stiffness in left side of neck.
255. Darting behind the neck, left side.
BACK: Tickling under the arms and along the dorsal spine. Horrid pain in
the sacro-lumbar region, when attempting to raise a weight. Contractive
sensation below the coccyx. Pain in the glutei muscles and sacrum, with
heat mounting to the face. 260. Painful stitch and beating between the
shoulder-blades. Sensation as of a warm liquid flowing from a sore in the
lumbar region. Throbbing at the sacrum. Painful breathing as from a sore
in the lumbar region. Beating in the lumbar region, with slight pulling
or shuddering. 265. Sense of heat, with throbbing and fatigue, in the
lumbar region. Prickling pain at the sacro-lumbar articulation in going
up-stairs. Inability to stoop forward, he then feels a pulling in the
lumbar region. Weakness in the sacro-lumbar region. Tearing and spraining
in the back, when sitting. 270. Painful weariness in the loins. Twisting
pain at the scapulo-humeral articulation. Pain in the sacrum, accompanied
by chattering of teeth. Twisting pain in the sacrum, exciting a nervous
laugh, with moanings. Pressure at the sacrum, with weariness in left
thigh. 275. Sense of worms crawling in the sacrum. Pain in the sacrum as
if gnawed by dogs. Sense of weariness in the lumbar region. Heaviness at
the sacrum when sitting. Pains in the sacrum preventing sleep, she has to
lie on her stomach.
UPPER EXTREMITIES: 280. Pain between the shoulders, worse when pressing
against the sternum. Pain in the back as if weary, affecting the lumbar
region. Pain and beating in left shoulder. Pain and prickling at right
shoulder. Weary pain near the left shoulder, behind. 285. Violent beating
under the left shoulder. Beating at the right shoulder. Rheumatic pain
in the right shoulder. Painful beating on the right shoulder, in the
left little finger, thumb, &c. Pain under the right shoulder, behind,
with beating in the chest. 290. Painful pressure on the left shoulder.
Rheumatic pain at the right shoulder. Pain at the right arm, shifting
to the little finger. Numbness of the arm. Burning pain above the right
elbow, with red spot. 295. The left arm is painful, with violent itching
of the index-finger. Trembling of the right arm. Pain as if her arm were
pulled. Pain in the bend of the left arm. Numbness of right arm. 300.
Pain in the bend of the right elbow. Numb pain from the wrist to the
upper part of the right arm. Crampy pain at right wrist, shifting to the
axilla. Pain at the right wrist, all the veins and fibres hurt. Painful
prickings in the wrist and along the left hand. 305. Pimple at the wrist,
on a red base. Pain at the right wrist. Dartings in right wrist and
thumb. Numbness of the right wrist. Pain in the wrists. 310. Numbness of
the left wrist, the hand being painful. Pain in right wrist, striking to
each finger. Beating in the arm and right wrist. Nervous pain from the
right elbow to the ring- and little fingers. Cracking in right forearm.
315. Numbness of the right arm, all the muscles hurt him. Trembling of
the right arm. Weight at the arms. Lancinating pain in the muscles of
the upper arm, and in the trapezoid muscle. Sense of weariness in the
arm, though lying down. 320. Pain in whole right hand. Burning at the
whole hand. Contusive pain at the back of the right hand. The ball of
the thumb of each hand is painful. Acute pain in the palm of the left
hand, proceeding from the index to the thumb in a circle. 325. Dry heat
in the hands. Dartings in the right hand. Heat in the nails of the left
hand and at the tips of the right fingers. Beating at right middle and
index-finger. Heat and pain at right index-finger. 330. Beating at the
tip of the right index-finger. Darting in first phalanx of middle-finger.
Contusive pain between the ring- and little fingers. Numbness of the
right index-finger. Lancination and pricking in left little finger.
335. Stitch in the right index-finger. Stinging in the ball of the
right thumb. Weakness of the finger-joints and wrists. Sensation as if
a portion of the nail of the right index-finger had become detached.
Sensation as of a splinter in the ring-finger. 340. Lancination in the
right index-finger.
LOWER EXTREMITIES: Beating under the right hip. Pain in right hip. Cold
and heavy pain at the left hip. Acute pain at the left hip. 345. Pain as
if sprained in the left hip-joint, when walking. Pain in right thigh,
high up, causing her to limp. Sensation in the thighs, as if bitten by
dogs. Sense of coldness in the right thigh. Weary pain on the left thigh,
when pressed upon. 350. Pain along the left thigh. Pain in the legs as
from weariness. Contusive pain at left leg. Tingling and twisting pain
in the right leg. Itching and smarting at the tibia, in front, at night.
355. Beating above the right knee. Slight itching at the knee, changing
to an acute pain when rubbed. Contusive pain at right knee. Spraining
sensation in left knee, with cracking when walking. Pain at the left
knee as if sprained. 360. Pain as from a sprain in left knee, with
dartings below the pan. Violent pain in the feet. Beating pain near the
right inner ankle. The left foot burns, the right foot is cold. Cold and
clammy feet, while lying down. 365. Beating in the right outer ankle.
Formication in the soles of the feet. Bruising pain at the outer ankle.
Cold and clammy feet, followed by heat. Heat and pain in the toes. 370.
Intermittent throbbing pain at the right little toe, with prickling.
Lancinating pain under the left big toe. Cramp in the toes. Pain as from
a splinter under the toe-nail.
SLEEP: Frequent yawning. 375. No sleep. Drowsy, with nausea. Restless
sleep. Heavy sleep at first, afterwards easy sleep and ready awakening to
consciousness. Starting during sleep. 380. Restless night, heat and sweat
all night. Drowsy in the afternoon. Dreams about travelling. Dreams about
dead bodies. Dreams about purchases. 385. Dreams about prisoners. Dreams
about dead bodies, decayed oxen, assassins. Dreams about a church-yard,
she places torches on the graves. Dreams about a sea-voyage. Dreams
with emissions. 390. Dreams about a revolution, &c. Restless sleep, with
dreams about wild beasts in a slaughter-house. Dreams about children with
their head half cut off. He dreams, that he was swimming in a river with
warm and green water.
FEVER: Moist heat mounting from the feet to the face. 395. Pulse
interrupted with roaring in the head. The body feels damp and cold. Cold
sweat at night. Burning all over. Alternate coldness and heat at night.
400. Fever, with inability to close her hands. Shuddering all over, with
oppression. Shuddering along the back and legs while taking breakfast.
Shuddering through the chest and between the shoulders. Cold feet, with
shuddering in the left leg. 405. Warm hands and cold sweat. Cold feet and
hot face. Shuddering. Cold feet with shuddering. She turns red and her
chest feels oppressed. 410. Cold sweat on the face and body.
CUTANEOUS: Miliary eruption in the joints. Vesicular pimples on left arm,
with itching. Miliary pimples at the bend of the elbow, with redness
around. Small red circle on the tibia, with red pimple in the middle.
415. Pimples all over, similar to those on the legs. Small smarting
pimples on the right knee, containing a fluid. Large pimples on the
legs, around the root of each hair. Painful pimples on the left side of
the tongue. Smarting red pimples on the right cheek. 420. Itching, red
pimples on the shoulders. Smarting red pimples on the side of the hips.
Vesicular pimples all over, with red spots. Miliary eruption in the face.
Large blotches on the legs. 425. Pimples leaving red spots behind. Small
itching pimple at the inside of the left elbow. Itching and pimples at
the forehead. Large red spot on the lower part of the left cheek. Small,
red pimples on the left cheek, with a white point in the middle. 430. Red
blotch on the right shoulder. Red spot and itching at the forearm. Red
spot on the back of the left hand. Red pimples on the left cheek. Small
vesicular pimples on the lower lip, itching. 435. Pimples in the face
and on the chin. The skin on the forehead feels stretched. Face mottled
with red spots. Painful pimples on left cheek and eyebrows. Itching of
the back, legs, arms. 440. Contusive pain in the back and the hips.
Lancinating pain shifting from the knees to the right elbow, shoulder,
right foot, &c. Uneasy when lying down. Pain in the back and chest. The
hands, feet and face feel hot to her, but clammy to others. 445. Liable
to starting. Internal trembling. Weakness of the legs and arms. Sense
of weariness as if strained, on waking. Weakness of the extremities.
450. Emaciation. Paleness, cold hands and feet, with weakness during the
pains. Fainting spell, with spasms, cramps in the calves and toes.
LEPIDIUM BONARIENSE (D. C.).
LEP. MASTRUCO.
This plant is very common in the neighborhood of Rio, where it is
found along the roads and in stony regions. It is herbaceous, with
numerous glabrous, erect stems, attaining a height of from twenty to
thirty inches; the radical leaves are petiolate, finely indented; the
superior leaves are alternate, sessile and almost linear. It blossoms
in September. The flowers, which form terminal spikes, are supported by
filiform pedicles; calix with four folioles; corol small, cruciform, with
four hypozynous petals, six tetradynamous stamens, short style, small,
subelliptical pod, which is somewhat crenated at the top; root fibrous,
simple, erect.
The fresh leaves are triturated.
In Brazil the Lepidium bonariense is used for similar purposes as the
Arnica. It is universally used in domestic practice. The pathogenesis of
this plant may be perhaps welcome to our profession.
_First day._—1. Sleeps well until midnight; no sleep since then; has
pains all over when stirring. Heat all over, with dull pain; she had the
most pain on the left side. Violent pain in the left arm before rising;
she cannot stretch it; the more she covers it, the greater is the pain;
the pain ceases on uncovering the arm.
_Second day._—Dizziness at nine in the morning; her head fell forward and
she imagined the floor was sinking under her; every thing turned with
her. 5. At eleven, heat in the face, left side. Dull pain at the stomach,
followed by desire to vomit. Cold as when she had her spasms. Hunger
after dinner. In the evening, hot face. 10. Pain as if scratched, for an
hour, followed by heat, at the feet. Beating pain above the left ear.
Acute stitching pain in the lower gums, for an hour. Itching in the right
ear, worse when stooping, for half an hour. Dreams that she is talking
with dead people; very restless. 15. Sad on waking.
_Third day._—On rising, pain as from a crown pressing on her head.
Pain round the right ear, as if pricked with pins, ceasing by rubbing
the part; for a quarter of an hour. Stitch in the right lung for five
minutes. Pain at eminence in the left cheek, with redness. 20. Heat in
the mouth, on the left side, as from eating spice. Palpitation of the
heart, felt in the side, with violent pain hindering breathing; worse
when stooping, ceasing when lying down. At noon, boring pain at the
vertex, left side, extending to the ear. Heat in the nose, and sensation
as of a current of cold air in the left nasal fossa. Pain in the nape of
the neck, right side, ceasing by rubbing the part and moving the neck.
25. Sensation as if a knife were slowly penetrating into the heart,
ceasing when pressing for a few minutes strongly against the region of
the heart. Prickings at the shoulder-blade, extending along the right
side of the neck. Itching at the right nostril. Pricking at the skin,
followed by itching. Pricking in the ear, down the jaw. 30. Lancination
in the right breast, less when standing erect. Stitching pain under
the axilla, in a half-moon shape. Prickings between the breasts. Pain
as from a band on the right side, worse when pressed upon, hindering
breathing. Lancination in the spine of the shoulder-blade, shifting to
the other shoulder; less when standing erect. 35. Prickings in the left
hypochondrium. Stitch under the axilla. Desire for chocolate, salad,
green fruit. Great thirst for vinegar. Lancination in the heart, in the
evening. 40. Oppression after eating. Convulsive trembling of the heart.
Pain at the pit of the stomach after eating, worse when walking, or when
touching the part. The blood which is discharged on the second day of the
courses is darker and coagulated.
_Fourth day._—Band in the side as the day before. 45. Passing
lancinations in the abdomen, sides and breasts. Lancinations from the
elbow to the shoulder-blade. Heaviness and pressure on the bladder when
urinating. The menses cease after twenty-four hours. Short sleep. 50.
Desire to vomit all night. Formication above the left shoulder. Slight
spitting of blood after coughing. Cutting as with a penknife below the
left breast. Heat in the throat with desire to vomit, and noise in the
ears when swallowing the saliva. 55. Constrictive pain in the head.
Vertigo, with disposition to fall forward. Thick expectoration, which it
is difficult to get loose, with roaring in the ears. Painful stitch at
the knee, less when walking. Stitch in the cheeks. 60. Lancinations under
the axilla. Colic in the umbilical region. Hard hearing. Throbbing at the
epigastrium. Very sad, thinks of sickness. 65. Pain in the bone of the
left thumb, with trembling when attempting to use it. When attempting to
read her eyes fill with tears.
_Fifth day._—Sad, uneasy, quarrelsome, dissatisfied, deep sleep.
_Sixth day._—Dim eye as if looking through a white gauze; when looking
at the sky, the air looks gray. Her left eye is full of water; the pain
is worse when moving, it follows the eyebrow, for six hours. 70. Crampy
pain at the right ring-finger, extending to the elbow, contracting the
flexor communis digitorum, with redness at the lower part of the nail;
for twenty minutes, it passes off in the open air. Toothache on the right
side, at one o’clock. Water in the eye, worse in the open air, ending
with itching, for ten minutes. Heat in the corner of the left nostril,
and stitch at the tip of the nose, for fifteen minutes. Pain at the
forehead, with beating in the left side, for ten minutes. 75. Merry, she
laughs about every thing. Desire to vomit after dinner, when inclining
her head forward. Difficult digestion, weight on the stomach. Salt,
thick and difficult sputa. Pains for five minutes, from the shoulder
to the middle of the back, with lancinations hindering breathing. 80.
Pain passing quickly through the right side of the head, from the top of
the left parietal bone to the eyebrow. Desire for tea. Lancinations in
the ears. Pain at the cardia as if cut with a penknife, short-lasting.
Thirst, dry mouth. 85. No sleep at night, the whole body feels tired as
in the third night.
_Seventh day._—Pain in the left lung, striking through the back, and
worse when carrying any thing heavy; for twelve hours. Stitch in the left
side; when drawing breath, the pain is felt like a cut with a knife, and,
after a short interval, coalesces with the former pain; three times.
Urine clear, white and not very thick. Sense as of a string at the right
breast, painless. 90. Pain in the teeth of the left lower jaw, striking
to the ear, and rendering her deaf for three minutes. She feels as if a
string were pulled from the shoulder to the ear. Toothache, the teeth
are soft and on edge, all day; every day since she took the drug, not
at night. Violent drawing pain from the shoulder to the ear, hindering
the motion of the head for three minutes. Shuddering, with paleness, and
margins around the eyes. 95. The fever abates by covering herself and
exciting a profuse perspiration; it is succeeded by malaise.
_Eighth day._—Cough at night, light sleep. Sad dreams, with fear on
waking, for a quarter of an hour. Itching at the tongue, like prickings,
for five minutes. Itching at the nipples, swelling of the glands,
hardness of the breasts; the itching does not last long. 100. Pain at the
pit of the stomach, which strikes to the left breast and shifts about;
stitch in both places at the same time. Itching under the chin, from
ear to ear; proceeding from the throat. Dry hacking cough which causes
a desire to spit, and, after repeated efforts, produces a salt saliva.
Pain in the left lower jaw, extending to the shoulder, for five minutes.
Pain as if a penknife were thrust in, with itching at the biceps muscle.
105. Pricking at the temple with itching, which spreads all over, all
day. Pain at the shoulder-blade as if a pin were stuck through the bone,
for three minutes. Pain in the middle-finger, while running, the finger
remained stretched for some minutes. Pain from the left hip to the knee,
with weakness of the leg which abates when sitting down. Pain and beating
in the left jaw, for ten minutes. 110. Vertigo and desire to vomit in the
evening. Cough with hoarse voice.
SECOND PROVING.
_First day._—Heavy sleep, with numbness on waking; sensation as if the
whole body were bruised. Drawing pain from the throat to the arm; her
tongue is thick as if very much swollen.
_Second day._—The left arm is very numb, pain in the left shoulder, as if
beaten by hammers. 115. Stitching pain at the pit of the stomach, after
eating. Crampy pain in the right hand, followed by shuddering all over.
_Third day._—No sleep until midnight. At seven in the morning, itching
at the corner of the right lip. Nose swollen on the left side, with
pain, which is less in the open air and worse when the parts are touched.
120. Painless lachrymation. Itching on the back of the hands. Weariness.
Desire to vomit, worse after half an hour; passes off by stirring
about. Pain in the pit of the stomach as from a band cutting the body
in two, for half an hour. 125. Pain at the bend of the knee, as if a
tendon were slowly drawn inwards. Buzzing in the left ear. Rheumatic
pain at the right shoulder-blade, for some minutes. Drowsy from noon
to three o’clock. Headache above the orbits and in the temples, worse
when raising the eyes or touching the parts. 130. Pain in the pectoralis
major, commencing under the axilla, and, in a few minutes, extending
to the heart. Worm-colic in the lower part of the abdomen, for five
minutes, with ineffectual effort to go to stool, and with tenesmus.
Frequent yawning. Pain at the right arm, like a blow with the hammer, and
numbness. Vertigo while steadying a basin with water, the head inclining
forward. 135. Pain in the right cheek, passing off by pressing on the
bony eminence. Compression as by a band around the waist, especially
at the epigastrium. Feeling of weakness in the stomach, with faint
feeling. Crampy pain in the right side of the neck, extending to various
parts of the shoulder and arm; relieved by pressure. Colic caused by
the damp air. 140. Coldness at the stomach, extending over the chest as
far as the throat. Pain with twitching of the muscles under the right
breast, extending and diminishing towards the axilla. Rheumatic pain and
stiffness of the left index-finger, which remains stretched for some
minutes. Contusive pain at the right hip, lessened by pressure. A cake
remains arrested in the œsophagus, after which it suddenly falls into
the stomach with a shaking sensation; the same symptom is experienced in
drinking. 145. Heat at the tip of the tongue as from spice, and sensation
as if the papillæ would expand and open. The abdominal functions are
regular. Dark urine. Stitching pain in the left axilla. Shuddering and
cold sweat in the air. 150. Violent coryza, inflammation, itching at the
nose. The limbs feel bruised. Desire for cressis, with loathing when
seeing it. Contraction of the leg, with stiffness of the bend of the knee.
_Fourth day._—Sensation as if a knife were plunged into the epigastrium
from without inwards. 155. Dry cough, with loss of breath. Violent
shock across the middle of the back. Throbbing in the head, from within
outwards, causing her to incline the head forwards. She imagines she is
abandoned in a church-yard, pursued by a phantom, and cries though nobody
hears her, with loss of voice next morning. Lancination from the ear to
the shoulder. 160. Beating in the forehead, causing her to incline her
head forward, not long. Sensation like a blow at the left big toe. Merry
after the sadness of the previous days (curative effects). Desire for
fruit and loathing of food.
_Fifth day._—Bleeding from the right nostril, the blood is black and
coagulated, with itching. 165. Pain in the right eye as from some round
weight, resting upon it, with itching in the inner canthus. Pain in the
shoulder extending around the neck like a band, with stitch in the pit of
the stomach and nape of the neck. Pricking and pressing pain around the
head. Crampy pain in the left hand. The nose bleed continues until one
o’clock, when it becomes violent, with red and bright blood.
_Sixth day._—170. Deep sleep. Pain as if a penknife were stuck along the
jaw, short-lasting. Crampy pain behind the neck, for five minutes. Short
pain from the temple to the chin, as if the face were cut with a razor.
Beating in the pit of the stomach, with pricking, worse when drawing
breath, not long. 175. Pain from the left ear to the lower part of the
neck, along the course of the carotid, worse when inclining the head
toward the right. The left ear feels as if stopped up, she does not hear
any thing with it. Loathing of meat.
_Seventh day._—Pain in the back as from a nail, extending to the
intra-scapular region. Pain in the right side arresting the breathing.
180. Shuddering all over as when the fever commences. Heat after the
cold, especially in the renal region. Constrictive pain at the heart,
extending to the left axilla. Desire to vomit, for half an hour.
Pricking at the tip of the middle-finger, drawing it up, so that she is
unable to stretch it.
THIRD PROVING.
_First day._—185. Very drowsy, shuddering in the legs as before an
attack of fever, very short. At 8, stitch in the left side, disappearing
of itself. At 11, tightness in the forehead as if pressed upon, for 15
minutes. Constant physical and moral torpor. Constant dull pain in the
head. 190. Frequent yawning. Desire to vomit before eating. Violent
headache at 4 in the afternoon. Dull pain in the abdomen, especially on
the right side, not aggravated by pressure. Headache with heat at the
forepart of the vertex. 195. Absence of ideas; inability to think, with
indifference for every thing. Comatose condition without being able to
sleep. Weight at the eyelids, with desire to close them. The outer air
feels very fresh. Pricking in the left side of the face. 200. Thirst.
Desire for coffee. Internal heat, and restlessness after lying down,
she has to get up again. Pulling at the forehead and at the root of the
nose. Heat in the stomach, with feeling of dryness and irritation. 205.
Throbbing in the back, which seems to proceed from the aorta. Aversion
to milk. Desire to walk about. Passing heat in the back, followed by a
general shuddering.
_Second day._—No sleep at night, general restlessness followed by
prickings all over, all night. 210. Eyelids weary, she raises them with
difficulty all night. At 4, pains in the abdomen, on the right side, the
same as the night previous.
_Third day._—The same restlessness, as the night before, followed by
sleeplessness. Pain in the left arm, she is scarcely able to raise it,
not long. Sickness at the stomach, followed by a desire to vomit, before
a meal. 215. Lancinations in the right eye, without redness, for three
hours.
_Fourth day._—Sickness at the stomach before eating. Weariness in the
legs for three hours. Heat in the back, not long, followed by shuddering.
FOURTH PROVING.
_Second day._—At 10 in the morning, pain all along the trunk, from above
downwards. 220. Pulling in the course of the left sartorius muscle. At
2, pain in the left gluteus maximus, as if contracted and twisted. At 6,
pain as if cut with a penknife, under the left axilla.
_Third day._—Laming pain at the left arm, when holding it still for a
time. Dreams about dead bodies, at night.
_Fourth day._—225. At 11, distress at the pit of the stomach, with desire
to vomit. Physical and moral prostration, loss of appetite, loathing
of food. At 2, heat in the head, with cold sweat and a little fever.
Constant desire to gape. At 6, heat in the head, no sweat. 230. Diarrhœa.
At 8 in the evening, violent colic, less when sitting, flatulence from
the bowels. Sour eructations.
_Fifth day._—At 7 in the morning, the abdomen feels sensitive as if sore.
Sensitiveness of the hairy scalp. 235. Short breathing. The abdomen feels
better. At 11, burning in the eyes. At 12, quick beating on the right
shoulder, as with a little hammer, for a minute. At 2, stitch in the
abdomen, on the left side. 240. From 4 to 7, faint feeling in the stomach.
_Sixth day._—At half past 6, pain in the gluteus maximus, for one hour.
_Seventh day._—At 3, palpitation of the heart. At night, while lying,
suffocative fit. Foul eructations all day. 245. Nightly pain in the whole
abdomen. At 5, buzzing in the right ear, for two minutes.
FIFTH PROVING.
_First day._—Violent lancinations in the right side of the chest for a
few minutes, below the third rib, every few moments. Acute pain at the
inner side of the right tibia.
_Second day._—Heaviness of the body. 250. Drowsy all day. Bad night,
nervous restlessness. Pains in the left brain, spreading from above the
left eye (which experiences a contractive sensation) to the vertex, the
back part of the head, and lastly to the nape of the neck where they
remain seated for a time. The pains seem to be seated in the cerebral
membranes, and succeed each other, never appear simultaneously. Sharp
stitching pain, in the region of the heart, with lancinations under
the false ribs. Violent headache, as if a hammer were beating inside
and as if the brain were bounding in an empty space, for half an hour.
255. Sharp pain in the right lower jaw-bone, all the teeth being sound.
Palpitation of the heart.
_Third day._—Night less restless. Sleeps all the time. Heaviness of the
head, with an undefined feeling of malaise in the brain, especially on
the left side. 260. Painful sensation at the right zygoma, for a short
time.
_Fourth day._—On waking, acute pains in the head and posterior cervical
muscles. Intense lancinating pains in the muscles of the right hand, and
its phalangeal articulations. Two hours, similar sensations in the right
shoulder-blade, accompanied by pains in the right wrist, all these pains
are well marked, but short.
_Fifth day._—Restless night, without any apparent cause; no sleep.
_Sixth day._—265. Prickling in the eyes, in the evening, as from some
astringent body. Eyeball and lids congested. Lancinations in the right
shoulder-blade.
_Seventh day._—Continual redness and pain in the eyes. Lancinating pains
above the eyes and in the temples.
_Eighth day._—270. Eyes still red, but less; no prickling.
_Ninth day._—Eyes well.
_Thirteenth day._—Acute and repeated pains in the cervical muscles, and
those of the left shoulder-blade. Violent headache in the morning, which
lasts until 2 o’clock.
_Fourteenth day._—Heavy and drowsy.
_Fifteenth day._—275. Recurrence of the pains in the neck and
shoulder-blade, in the morning. Heavy and drowsy; unable to apply himself
to a serious work; at 3, continued his work with ease.
_Sixteenth day._—Acute pains in the muscles of the neck and
shoulder-blade. Violent headache, in the evening, with sense of
compression in the forehead; from temple to temple. Dry mouth and throat.
_Seventeenth to nineteenth day._—280. Violent headache, all day, from
ten every morning until night. Violent palpitation of the heart. Violent
pains in the muscles of the neck, thigh and left leg, frequently
recurring, but short. (Rising of air in the evening, without acidity).
_Twentieth day._—No headache. Same symptoms as on the preceding days, in
the muscles of the left side. 285. Passing palpitations. Eructations.
Loathing of food, especially meat. Pains in the maxillary bones, as if
all the teeth were affected.
_Twenty-first day._—Lancination above the left eye and in the left
temple. 290. Lancinations in the left jaw-bone. No appetite, loathing of
meat.
_Twenty-second and -third day._—No appetite. Pains in the left side of
the head. 295. Palpitations of the heart.
_Twenty-fourth day._—The stomach feels better. Slight darlings in the
head, always on the left side.
_Twenty-fifth day._—The appetite returns.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL AND MORAL: 1. She imagined the floor was sinking under her.
Inability to think. She imagines she is pursued by a phantom in a
church-yard, cries, with loss of voice next morning. Vertigo, with desire
to vomit. 5. Vertigo when stooping slightly. Sad and quarrelsome.
HEAD: Painful pressure on the head. Headache, with heat at front-part of
vertex. Headache above the orbits and in the temples. 10. Constrictive
pain in the head. Headache, with sense of compression in forehead.
Beating headache, as if the brain were bounding. Pains in the left brain,
spreading to the occiput and nape of the neck. Boring pain in the vertex.
15. Pricking and pressing pain round the head. Throbbing in the head,
causing one to bend it forward. Pricking at the temple, and itching all
over. Tightness of the forehead. Pulling at the forehead and root of the
nose. 20. Lancinations in left side of the head. Heaviness of the head,
with indescribable malaise in the brain, especially the left. Heat in the
head, with cold sweat and fever. Sensitiveness of the hairy scalp.
FACE, EYES, EARS: Pain in the right cheek, passing off by pressing on the
bone. 25. Pricking in left side of the face. Cutting pain from the temple
to the chin, across the face. Heat in left side of the face. Heat in the
corner of the left nostril, with stitch in the tip. Nose swollen and
painful on the left side. 30. Coryza, inflammation, itching of the nose.
Discharge of black blood from the right nostril. Heat in the nose, with
sensation as of a current of cold air in left nasal fossa. Buzzing in
the right ear. Beating pain above the left ear. 35. Itching in the right
ear, worse when stooping. Dartings in the ears. Buzzing in left ear.
Pricking pain round the right ear. Prickling in the eyes. 40. Burning in
the eyes. Eyelids weary at night. Redness and pains of the eyes. Dartings
in the right eye. Dimness of sight as if looking through a white gauze.
45. Lachrymation, with itching. Pain in right eye as from a round weight
resting upon it.
TEETH, JAWS: Sticking pain in the jaw. Painful beating in the left jaw.
Lancinations in the left jaw. 50. Pains in the jaws, as if in the teeth.
Pain in the lower teeth, with deafness. Toothache, as if soft and on
edge. Stitching pain in the lower gums. Itching under the chin, from ear
to ear.
MOUTH, THROAT: 55. Pricking itching at the tongue. Drawing pain from the
tongue to the arm, with sensation as if the tongue were swollen. Smarting
at the tip of the tongue. Dry mouth and throat. Heat in the throat with
desire to vomit and noise in the ears on swallowing.
GASTRIC: 60. Aversion to meat. Desire for tea. Desire for fruit, with
loathing of food. Desire for cressis, with loathing when seeing it.
Desire for chocolate and salad, vinegar. 65. Desire for coffee. Desire to
vomit. Sour eructations. Foul eructations. Prostration with loathing of
food. 70. Loathing of food. A cake descends into the stomach suddenly,
with a shaking sensation. Oppression after eating.
STOMACH, BOWELS: Faint feeling in stomach. Distress in pit of stomach,
with desire to vomit. 75. Heat in stomach, with feeling of dryness.
Sickness at the stomach, followed by a desire to vomit, before eating.
Pain at the pit of the stomach, after eating. Stitching pain in the pit
of the stomach after eating. Weak feeling in the stomach. 80. Pain in
the pit of the stomach, as if cut through. Beating and pricking in the
pit of the stomach. Throbbing at the epigastrium. The abdomen feels
sensitive. Cutting pain at the cardia. 85. Lancinations in the abdomen
and sides. Worm-colic, with tenesmus. Compression as by a band round the
waist. Colic in damp air. Sense as of a knife being plunged into the
epigastrium. 90. Colic. Stitch in left side of abdomen.
STOOL, URINARY, &c.: Diarrhœa. Weight and pressure at the bladder when
urinating. Dark urine.
BRONCHIAL: 95. Dry cough, with loss of breath. Cough with hoarseness.
Hacking cough, with salt saliva. Cough with slight spitting of blood.
Salt, thick sputa. 100. Stitch in the right lung. Pain in the right
side, arresting the breathing. Twitching pain in the muscles under the
right breast. Coldness from the stomach to the throat. Pain in the
pectoralis major. 105. Sense as of a string at the right breast. Pain
in the left lung, through to the back. Itching at the nipples, swelling
of the glands, hardness of the breasts. Sensation as of a band in the
side. Pricklings between the breasts. 110. Pain all along the trunk.
Lancinations in the right chest. Shortness of breath. Palpitation of the
heart, with pain hindering breathing. Convulsive trembling of the heart.
115. Sense as of a knife slowly penetrating into the heart. Constrictive
pain at the heart, extending to the left axilla. Palpitation of the
heart. Sharp stitching pain in the region of the heart, with lancinations
under the false ribs.
BACK: Acute pains in the muscles of the neck and shoulder-blade. 120.
Pricklings from the shoulder-blade along the right side of the neck.
Sensation as if a string were pulled from the shoulder to the ear. Crampy
pain in right side of the neck, extending to the arm. Darting from the
ear to the shoulder. Pain from the shoulder round the neck, like a band,
with a stitch in the pit of the stomach and nape of the neck. 125.
Crampy pain behind the neck. Pain in the side of the neck, worse when
turning the head to the right side. Throbbing in the back. Passing heat
in the back, followed by shuddering all over. Darting in the spine of
the shoulder-blade, shifting to the other shoulder. 130. Pains from the
shoulder to the back, with lancinations hindering breathing. Sticking
pain at the shoulder-blade. Shock across the back. Pain in the back as
from a nail.
UPPER EXTREMITIES: Stitching pain in the left axilla. 135. Formication
above the left shoulder. Pain under the left axilla, as if cut with a
penknife. Quick throbbing on the right shoulder. Violent pain in left
arm, worse when covered; she cannot stretch it. Pain as from a blow at
the right arm, with numbness. 140. Numbness of the left arm, with pain
in the shoulder as if beaten by hammers. Darting from the elbow to the
shoulder-blade. Pain in left arm, she can scarcely raise it. Laming
pain at left arm, when holding it still. Crampy pain in left hand.
145. Itching on the back of the hands. Crampy pain in the right hand,
followed by shuddering all over. Lancinating pains in the muscles of the
right hand and shoulder-blades. Rheumatic pain and stiffness of left
index-finger. Crampy pain at the right ring-finger. 150. Pain in the bone
of the left thumb, with trembling when attempting to use it. Prickling at
the tip of the middle-finger, which draws it up.
LOWER EXTREMITIES: Contusive pain at the right hip. Pulling along the
left sartorius muscle. Pain in left gluteus maximus as if contracted.
155. Contraction of the leg, with stiffness of the bend of the knee.
Acute pain at inner side of right tibia. Pain from the left hip to the
knee, with weakness of the leg. Pain in the bend of the knee as if a
tendon were slowly drawn inwards. Pain as if scratched at the feet,
followed by heat. 160. Sense as of a blow at the left big toe.
SLEEP, &c.: Desire to gape. No sleep after midnight, with pains all
over when stirring. Comatose condition, but no sleep. Heavy sleep, with
numbness and sense as if bruised on waking. 165. Drowsy, and shuddering
in the legs. Restless at night, followed by prickings all over. Heavy and
drowsy. Restless night. Suffocative fit at night. 170. She dreams that
she is talking with dead persons. Sad dreams with fear on waking. Dreams
about dead bodies. Internal heat with restlessness; she has to rise. Heat
after the cold, especially in the renal region. 175. Shuddering and cold
sweat in the air. Violent pain in the muscles of the neck, thigh and left
leg. The limbs feel bruised.
PANACEA.
We regret to say that we lost the drawings and the notes which we had
collected about the tree called by the Brazilians “panacea” on account of
the many ailments for which they use it. It is called in Brazil, _azougue
dos pobres_ (mercury of the poor), _cabedula_, and _erva carneira._
This tree is exceedingly common in Brazil; knowing its name, foreign
homœopathists will find it perhaps easier to procure the plant.
_First day._—1. Heaviness in the forehead, worse when drowsy, at 10 in
the evening. Heat followed by considerable cold, at half past 10.
_Second day._—Bitter mouth, in the morning after rising, at 5. Pain at
the shoulder-blade by turning the head to the left side. 5. Nausea.
Spasmodic yawning arrested suddenly. Cramp from the index-finger to the
elbow. Violent headache, worse when inclining to the left side, at 6.
Pain at the forehead and temples. 10. Pain at the loins as if bruised, at
6. Globus hystericus at the pit of the stomach, she cannot lace herself.
Hunger, with loathing of food. Fainting turn. Pain from the right wrist
to the elbow. 15. Vertigo with increase of the headache, at 6. Heaviness
of the head. Drowsy. Tearing, from the chest to the throat, at 7. Pain
like a blow with a hammer, at the left shoulder. 20. Dizziness, she
inclines backwards as if she would fall, at half past 7 in the evening.
Pain at the navel as if cut by a penknife, all around the abdomen and
terminating in the loins. Heat at the tongue, with sensation as if little
drops of ice-water were upon it, at 9 in the morning. Pain at the temples
as if in a vice. Very drowsy at noon, with heaviness of the eyes. 25.
Cramps from the feet to the bends of the knees. Empty feeling in the
stomach, with desire to eat. Hunger causing a burning at the stomach. The
knees give way, at 4 in the evening. Desires to be alone. 30. Shuddering
in the open air, at 7 in the evening. She cannot kneel for any length of
time. Pain in the chest, rising upwards, with pulling. Pain above the
orbits as if a rusty saw were rapidly moved across the part. Sensation as
if the toe-nail were torn off. 35. Weariness as after a long journey, at
8 in the evening.
_Third day._—Numbness of the left hand, it cannot be stirred, at 6 in the
morning. Pain as if stabbed with a knife, in the sides and navel. Pain in
a decayed tooth, as if a penknife were thrust in, at 7 in the morning.
Aching pain at the vertex, with dizziness; this pain shifts to the left
eye, followed by sensation as if a rocket were rushing out of it, at
half past 7. 40. Sense of choking at 9 in the morning. Trembling of the
right hand. Dissatisfied with herself, every thing is unpleasant to her.
Headache which increases her dissatisfaction. Shuddering all over.
HAHNEMANN’S ARRANGEMENT.
HEAD, &c.: Vertigo. Dissatisfied with herself, more so when she has the
headache. Pain at the temples as if in a vice. Aching pain at the vertex
with dizziness, shifting to the left eye, with sensation as if a rocket
were rushing out of it. Heaviness in the forehead. Headache worse when
inclining the head to the left side. Sawing pain above the orbits. Pain
in a decayed tooth, as if a penknife were thrust in. Heat at the tongue,
with sensation as if little drops of ice-water were upon it. Sense of
choking.
GASTRIC, &c.: Hunger with burning at the stomach. Nausea. Hunger, with
loathing of food. Bitter mouth, after rising from bed. Globus hystericus
at the pit of the stomach. Empty feeling in the stomach. Pain in the
sides and navel as if stabbed with a knife. Cutting pain; from the navel
all around the abdomen. Pulling pain in the chest. Tearing from the chest
to the throat. Pain at the loins as if bruised.
EXTREMITIES: Pain at the shoulder-blade when turning the head to the left
side. Pain in the right forearm. Trembling of the right hand. Numbness of
the left hand. Cramp from the index-finger to the elbow. Cramps in the
legs. Sensation as if the toe-nails were torn off. Pain at left shoulder
as from a blow. Spasmodic yawning. Shuddering all over. Shuddering in the
open air. Heat followed by cold. Weariness. Fainting turn.
SOLANUM TUBEROSUM ÆGROTANS.
SOL. T. ÆG.—DISEASED POTATO.
A description of the potato in a work destined for European
pharmaceutists and physicians, would be entirely useless; so well and so
universally known is this plant in Europe. However, since our work will
get into the hands of persons who are less familiar with the productions
of the European continent, we deem it advisable to subjoin a drawing and
a short description of this plant. The potato is a native of Chili; it
is an herbaceous plant, with a branchy stem about one or two feet high.
Its leaves are pinnatifid, with leaflets that are oval, entire, slightly
hairy on their lower surface and almost opposite. Smaller folioles
sometimes arise between the larger ones. The flowers constitute corymbs
either erect or inclined; calice in five parts; corol of a white violet
with five equal divisions; five stamens attached to the basis of the
corol; one style and stigma, fleshy berry with two chambers. The roots
develop tubercles of different sizes and called potatoes. The potato-rot
first reveals itself by brown spots irregularly distributed through
the interior of the tubercles; gradually these spots are transformed
into white points of a cottonny appearance which may be compared to
the cryptogamia termed byssus, and found on damp wood. From this point
a general process of decomposition sets in, and the potato exhales an
insupportable nauseous odor. In our provings we have made use of a potato
in an entire state of decomposition, without, however, being completely
rotten; there were brown portions intermingled with those byssus-shaped
parts described above.
HOMŒOPATHIC TREATMENT OF THE POTATO-ROT.
Human pathology is not the only field of the homœopathist. He should take
an interest in every species of suffering, and endeavor to restore the
harmony of the organic kingdom wherever it has been disturbed by some
accidental cause. Homœopathy is a vast, unitary science. The healing art
is one; there is no such thing as one healing art for man and another for
the animal, though it is on man that we should prove our drugs because he
is the complex of the various kingdoms of nature.
The question now occurs, how is the potato-rot to be treated? It is
evident that the great point is to _prevent_ the disease, and, for this
purpose, we must endeavor to remove the cause. _Principiis obsta_, has
ever been the fundamental rule of medical treatment.
In order to attain this end, we have deemed it necessary first to
ascertain the effects which the diseased potato would produce on a
healthy person and afterwards to find out what drugs produce similar
effects. We might have instituted our provings on the potato itself, and,
among a number of drugs, might have discovered the one that would produce
a disease similar to the rot. But this mode of investigation would have
been too long and uncertain, whereas the proving on the human body is
simple and direct, and is, we think, the true mode which Providence has
designed we should pursue even in regard to the potato-rot.
It is true, man cannot be assimilated to the myriads of organized
beings that surround us; man constitutes the highest link in the chain
of beings; he is the complex of the animal life on our globe, and the
most perfect type to which all inferior existences can be referred; he
is a microcosm containing all the wonders of the universe; he is the
responsible administrator of this earth. Man alone is able to produce a
true pathogenesis by revealing the most evanescent as well as the most
characteristic and most permanent symptoms, or lesions of sensation.
On plants and animals we can only perceive disordered functions,
disorganizations of tissues, or acute pains as manifested by gestures or
cries; but the truly dynamic action can only be properly perceived and
described by man.
The veterinary homœopathist does very well in selecting his remedy by
the human pathogenesis. Why should not the same mode be applicable to
vegetables? We have invited our fellow-beings to try it; we have not
only invited them to teach, and to cure, and to make themselves sick,
in order to discover the true means of healing; but we have encouraged
them to suffer themselves to be persecuted, and even imprisoned, as a
reward for their labors of love, we have said to them; whilst the world
is hesitating whether it should accept or reject the blessing offered by
Hahnemann, let us lose no time; there are other regions where the evil is
still triumphant, and where truth is not even known by name; let us expel
error from its last hiding-places. And we have never failed in meeting
corresponding souls that would hear us and follow us. And thus it is that
homœopathy, this physical reflex of the Christian redemption, combats
evil by itself, pursuing it from region to region until it shall have
been exterminated from the world.
Now let us describe the practical part of our proving.
From the first, frontal headaches, with pressure above the orbits, have
been observed with much regularity not only by the three provers whose
symptoms are published, but also by other provers who continued the
proving only for a few days.
Until the 20th day, these headaches were often accompanied by fever,
with chill, heat, sweat, shudderings followed by sore throat, cough and
greenish mucous expectoration.
The palpitation of the heart which occurs during the whole period of
the proving, and with particular violence at the end of the third
proving, appears to be represented in the case of the second prover by
violent muscular pulsations occurring in the same chronological order.
The hard, large-sized, fragmentary stools, and their painful expulsion
which sometimes caused a falling of the rectum; the frequent emission of
flatulence preceded or accompanied by colic, with sensitiveness of the
abdominal integuments in the case of the first prover, are very constant
symptoms of this drug; they were observed from the first and increased
until the last days of the proving.
We will likewise point to the general or partial weakness, which, in the
case of the third prover, were followed by violent pains in the loins.
The white coating of the tongue which was observed on the first day,
gradually limited itself to a yellow line along the middle. Among the
less general symptoms which were observed during the whole time of the
proving, we may note the want of appetite, the bitter taste of food,
the cutaneous eruptions, the swelling of the mucous membrane of the
palate, the thick urine, and lastly the pain in the groin or the right
ileo-femoral articulation.
In the emotive sphere the drug induced a great irritability. The dreams
about a change of form occurred very generally to the three provers. The
second prover had the same dreams on two successive nights.
After a careful comparison of the symptoms of the Solanum tuberosum
ægrotans with those of the other known remedies of our Materia Medica, we
have found them to agree with the symptoms of the following drugs which
we enumerate in the order of their importance:
1. _Bryonia_;
2. _Arsenicum_;
3. _Plumbum_;
4. _Nux-vomica_;
5. _Sepia_;
6. _Strontiana_;
7. _Viola-tricolor_;
8. _Squilla_;
9. _Pulsatilla_;
10. _Graphites_;
11. _Alumina_;
12. _Mercurius_;
13. _Natrum-mur_;
14. _Ignatia_;
15. _Calcarea_.
We have no doubt that Bryonia and Arsenicum will prevent the rot; but, to
be frank, we believe that, in this case at least, the isopathic method
of treatment will prove more successful than the homœopathic. It is
well known that the mode of preparing our drugs for medicinal purposes,
modifies their action a good deal. This result is principally obtained by
rubbing them down with sugar of milk, which is not an inert substance as
Hahnemann believed, but is on the contrary endowed with the most useful
powers of action. The sugar of milk effects a preliminary digestion of
the drug, and, by imparting to it vital qualities, fits it for medicinal
purposes. Do we not know that certain animal products are preferable
to corresponding mineral substances? Is not the calcarea prepared from
the oyster-shell preferable to the chemically prepared carbonates and
phosphates of lime? Are not the poisons of serpents destined to occupy
the first rank among the polychrests?
To return to our subject, the medicinal preparation obtained from the
diseased potato is not the original poison as used by nature, but the
poison modified in consequence of its having been previously engrafted on
a living tubercle.
Our mode of inoculating either the isopathic or homœopathic preparation
is as follows. Before putting the potato in the ground we perforate it
with a big needle, and into this hole we insert a single globule of the
third attenuation.
This operation is simple and easy. It can be applied on a large scale and
we think that by its means the potato will be preserved for a long time
yet to the European continent.
First prover: _Van-Dyck_, 26 years old, of a sanguine nervous temperament
and a robust constitution.
_First day._—1. Painful stitch in the right side, a few moments after
taking the drug. Acidity and eructations, at 9 in the evening.
_Second day._—On waking, weight above the eyes and in the forehead, as
the morning after being intoxicated. Shuddering and sensation of cold
internally, at noon. 5. Scanty and difficult stool, in the shape of small
hard balls, in the evening.
_Third day._—He dreams that he is to dress and draw the body of a drowned
man; this body bounded up every moment and fell back either on his
clothes or on his drawing board. The mucous membrane of the palate seems
to detach itself here and there. Cross; he blames every thing, and cannot
bear that any thing near him should be disturbed.
_Fourth day._—Difficult stool in small red balls.
_Fifth day._—10. Stool as above.
_Sixth day._—Horrid colic, as if the bowels were violently twisted; 15
minutes after, hard and copious stool, followed by two almost liquid
stools (at night).
_Seventh day._—Copious and liquid diarrhœa, of a greenish yellow, in the
morning. Prickling around the eyelids; on their internal surface they are
red and congested. Tongue coated white. 15. White sordes on the teeth.
(Profuse lachrymation). Little appetite. Pulse rather agitated.
_Eighth day._—The median line of the abdomen from the sternum to the
hypogastrium is painful to the touch. 20. Thirst. Little appetite.
Sensation of warmth about the head, at 4 in the evening.
_Ninth day._—Dreams about magic, men being transformed into speaking
animals, changes at night, &c. Heat in the canal of the urethra, after
urinating. 25. The urine deposits a yellowish sediment. Small pimples on
the back, causing a violent itching. Sneezing in going up-stairs.
_Tenth day._—Heaviness on the eyes. Slight beating in the temples. 30.
Mounting of heat to the head from time to time.
_Eleventh day._—Pricking around the eyelids, on waking. Itching of the
back. Sweat on doing the least work. Heaviness of the head.
_Twelfth day._—35. Heaviness in the head which is at times very violent,
especially when raising the head again after stooping. Smarting and
prickling in the eyes. No stool for five days past.
_Thirteenth day._—Heaviness of the head, worse in the morning than
evening. Ordinary stool. 40. Difficult digestion. Sneezing after going
up-stairs. Likes to loiter about.
_Fourteenth day._—Heaviness of the head. Ordinary stool. 45. He would
like to go to bed, but is too lazy, at 10 in the evening. Pains in the
thighs, above the knee-pan.
_Fifteenth day._—(Lachrymation on waking). Slight heaviness of the head.
Greenish yellow coating on the tongue, along the middle. 50. White slime
on the teeth. Headache at noon. Lancinations in the region of the heart.
Chilliness with chattering of the teeth. Smarting at the eyes, in the
evening. 55. Not much appetite. Sneezing. Lips cracked, bleeding and
almost raw.
_Sixteenth day._—Smarting at the eyelids. Tongue slightly coated white.
60. White mucus on the teeth. Dreams about his daily business. Flatulence
and eructations. Agitated pulse. Sneezing at 4 in the afternoon. 65.
Smarting and prickling at the eyes.
_Seventeenth day._—Colic followed by two stools at 4 in the morning. The
right umbilical region is painful to contact.
_Eighteenth day._—Colic. Not much appetite. 70. Sneezing at 5 in the
evening.
_Nineteenth day._—Prickling in the throat, inducing cough. Dry cough.
_Twenty-third day._—Heaviness of the head on waking.
_Twenty-fourth day._—Headache aggravated by the smell of alcohol and
disappearing at 3 in the evening.
_Twenty-fifth day._—75. Colic on waking. Frequent emission of flatulence.
Pains between the shoulders (at 10 in the evening).
_Twenty-sixth day._—He dreams that his hands are cut in pieces. Tickling
in the throat causing a cough.
Second prover: _Charles Dieudonné Jolly_, 24 years old, nervous-sanguine
temperament, robust constitution.
_First day._—80. Pressure at the root of the nose. Dreams about religious
things.
_Second day._—Heaviness of the head, in the morning. The head and
especially the forehead, feel dull as during a catarrh, all the
afternoon. Colic after eating. 85. Sexual dream, followed by a dream
about women that are changed to animals.
_Third day._—Frequent emission of flatulence, in the morning. Tongue
slightly coated white, in the morning. Colic and twisting in the stomach
after eating. Salt taste in the throat. 90. Pressure in the forehead and
above the orbits.
_Fifth day._—Slight yellowish-white coating on the tongue, in the
morning. Heat in the face, at half past 4 in the afternoon. Pain as if
sprained at the right coxo-femoral articulation, posteriorly. Flow of
ideas, at 5. 95. Beating at the middle portion of the triceps brachialis,
at 8.
_Seventh day._—Wakes very early since the third day. Itching at the ball
of the thumb, at 9 in the evening.
_Eighth day._—Wakes very early. Thin yellowish coating on the tongue, in
the morning. 100. Prickling in the lumbar muscles, at 6 in the afternoon.
_Ninth day._—Stitch in the left ring-finger, at 7 in the morning. Stitch
and sharp pinching in the right groin, near the inguinal ring; this pain
was felt shortly after an ordinary stool, while raising one leg as if one
would mount three steps at once, at 11 in the morning. Beating in the
left thigh at 4 in the afternoon, while sitting. Drowsy at half past 7,
waking very early.
_Tenth day._—105. Beating under the right shoulder, at 9 in the evening.
Drowsy at 8 o’clock in the evening.
_Eleventh day._—Weight in the left testicle, the whole day, also in the
evening while sitting.
_Twelfth day._—Violent pulsations at the lower part of the vastus
internus muscle, in a demi-circle, for an hour and a half, in the morning.
_Thirteenth day._—Beating in the lumbar muscles at 4 in the afternoon.
_Fourteenth day._—110. Headache. Repeated sneezing, at half past 8 in the
evening.
_Fifteenth day._—Sense of weariness in the muscles of the right thigh,
after walking. Involuntary crowding of heterogenous ideas on one’s mind
while listening to a discourse or attending to some work; frequently
during the proving.
_Sixteenth day._—Tongue coated white, in the morning. 115. Contraction
and beating at the left superior eyelid, at 7 in the evening. Slight
colic and copious flatulence all night.
_Seventeenth day._—Restless sleep. Flatulence in the evening. Hard and
scanty stool.
_Eighteenth day._—120. He dreams that he will fall from a tower. Violent
beating of the heart in raising himself. Pricking in the right side of
the tongue, from noon until 3. Roughness in the throat, with thirst, in
the evening. Cough and yellowish mucous expectoration, at night.
_Nineteenth day._—125. He dreams that he is in danger of falling from
the roof of a house. Swelling of the mucous membrane of the internal
alveolar margin of the two incisores and the left canine tooth. Violent
frontal headache and coryza all day. Pain as if sprained at the right
scapulo-humeral articulation, after having rested on the elbow, in the
evening, in bed. Restless night.
_Twentieth day._—130. Confused dreams. Agitated pulse in the morning.
Coryza.
_Twenty-first day._—Confused dreams. Frontal headache. 135. Coryza.
Agitated pulse. Sweats all over, in the morning, in bed. Strong
pulsations at the perineum, loins and right ring-finger, at half past
4. Violent frontal headache at 5 in the afternoon, while walking. 140.
Large, hard, fragmentary stool. Urinates all the time during stool.
_Twenty-third day._—Strong pulsations in the vertebral region, in the
morning while lying. Whizzing in the left ear, at 5 in the evening.
Disposed to remember past journeys; flow of ideas about theories, &c.
_Twenty-fourth day._—145. Aching pain in the right hypogastric region,
towards the ring, after a long walk.
_Twenty-fifth day._—Reddish urine, with mucus floating in it.
Third prover: Mme _Al. J—_, 26 years old, of sanguine temperament, good
constitution.
_First day._—Tearing in the chest and throat, immediately.
_Second day._—Sexual dream. Dull colic in the hypogastric region, at
night.
_Third day._—150. Dream about witchcraft. Difficult digestion accompanied
by twisting in the stomach, after breakfast and dinner. Hard and knotty
stool; after stool, renewed urging, with smarting at the anus. Falling of
the rectum. Sense of contraction at the sphincter. 155. After stool, the
rectum alternately descends and returns again. The falling of the rectum
is accompanied by shuddering all over, for ten minutes.
_Fifth day._—Palpitation of the heart, at 11 in the evening, while lying.
_Sixth day._—Palpitation of the heart, at 7 in the morning. Colic at the
stomach, after eating, at 6 in the evening.
_Seventh day._—160. Tearing in the throat, at 8 in the morning. Tongue
coated white.
_Eighth day._—Restless sleep, she dreams that she is eating human flesh.
The least thing puts her out of humor. Palpitation of the heart, at noon.
165. Palpitation of the heart, at 11 in the evening, at three different
periods.
_Ninth day._—Thick tongue, at 2 in the morning.
_Eleventh day._—Restless sleep. Cold sweat at night, while lying.
_Twelfth day._—Sense of spraining in the ileo-femoral articulation,
causing a pain in the womb; while making a trifling exertion. 170.
Flatulence; sometimes is unable to expel them. Headache. Contraction
of the sphincter ani. Lancinating pain at the forehead, until 9 in the
evening. Twisting colic. 175. Stool always hard and difficult. Heat
at the anus, after stool. Weeping of the right eye, for some minutes.
Frequent urging to stool. Shuddering all over, every moment, at 9 in the
evening. 180. Eructations in the evening. Flatulence in the evening.
Quarrelsome mood.
_Thirteenth day._—No sleep. Heat all over, with sweat. 185. Agitated
pulse. She dreams that she is floating in a river and cannot get out.
Flushes of heat in the face, now and then, especially while eating. These
flushes are followed by chilliness. (Is unable to close her hand). 190.
Irregular pulse, at times feeble, at others strong. Frontal headache with
dulness, and disposition to incline forwards. Lazy. Weary all over, she
has to lie down, at noon. Little appetite. 195. Pressure at the chest.
Thirst. Shivering while drinking cold water, or washing her face with it.
Headache ceasing for a while and then recommencing again. Lancinations
with sensation as if the brain would fly to pieces, in going up-stairs.
200. Vivid redness on the right malar eminence. Small red pimples on
the cheeks. Shuddering now and then. Congestion of the sclerotica. Red
face at three in the evening. 205. Flush of heat all over, at half past
3. Sensation, while stooping as if the brain would bound in the skull.
Heat at the vertex, which spreads all over, at 4. Sensation in the left
hypochondrium as if a spring were rolled out. Sense of fainting, she
has to stand still. 210. Acute pain in the right pectoralis major when
drawing breath. Borborygmi. Twisting of the bowels, at half past 10.
Colic and shuddering. Dry cough in the evening. 215. Headache decreases
in the evening. Flatulence. Red and hot face. The skin of the face peels
slightly.
_Fourteenth day._—Heat at night, disturbing the sleep. 220. Sense of
weariness in the limbs, on waking. Dulness of the forehead. Tongue
coated white. In the morning, taste of raw potatoes. Menstrual blood
rose-colored, at 9 in the morning. 225. Borborygmi, in the morning. At
the least movement she feels as if a hollow body were turning rapidly
round in the chest, with a rattling noise; she then fancies she will
faint, at 8 in the morning. Frontal headache all day. Smarting and
painful sensation at the fifth dorsal vertebra, when the clothes rub
against the part. Little appetite. 230. Stiffness of the posterior
cervical muscles. Dark redness and warmth of the cheeks. Heat all over
in cold and damp weather. The menstrual flow is interrupted. Repeated
sneezing, followed by a slight cough, every evening at 5, from the tenth
day. 235. Smell of blood, as if nosebleed would take place, at 7 in the
morning.
_Fifteenth day._—Restless sleep. Last evening’s dinner does not sit well
on her stomach, with acidity at night. Doughy mouth, in the morning.
Weariness all over, when rising. 240. Drawing pain in the right lower
limb, posteriorly, from the gluteus maximus to the heel. The menstrual
flow is interrupted. When bending the knee, pulling pain in the posterior
and internal muscles of the thigh. Hypochondria. Sadness. 245. Every
thing is disagreeable to her, she would like to go far away. Small
pimples on the lower part of the neck and on the right knee, they are
very red at the base, with a white point in the centre; they disappear in
an hour. Sense of weight in the nape of the neck, at half past 11. The
head feels heavy, she can scarcely keep it erect. Pain as from weariness
in the back and the posterior muscles of the thighs and arms. 250.
Dulness of the head. Pain as if bruised, hindering her movements in bed.
Very hot hands. Slight nosebleed, at 11 in the morning. She walks with
difficulty, she fears, she will lose her muscular powers. 255. The pain
is worse in the day-time and less in the evening. The menstrual flow is
interrupted. The epidermis of the face peels off. Numerous small pimples
on the face. Desire to stretch.
_Sixteenth day._—260. No sleep; disturbed sleep. Oppression, owing to the
dinner of last evening not sitting well on her stomach, she has to rise
at 3 in the morning. Eructations followed by rumbling in the stomach,
ceasing after drinking a glass of water with sugar. Tongue coated white,
with a yellow line along the middle. (She would like to break every
thing, on account of not being able to understand a certain phrase). 265.
Doughy mouth, in the night. Alternate heat and shuddering, in the night.
(Has the taste of potatoes in the mouth, all night, from last evening’s
dinner). Beating in the left temple. Stiffness in the posterior cervical
muscles. 270. The sacrum is painful when touched or during a walk. After
eating, choking and difficulty of breathing, caused by dryness of the
mouth. Very fine pimples and intolerable itching at the labia majora.
_Seventeenth day._—Restless sleep. Is roused at 4 in the morning by
a stomach-ache with eructations, for an hour. 275. Headache during a
half-slumber. Heaviness at the vertex in the evening. Shuddering and
burning, in the evening, in bed. Palpitation of the heart, while lying
down. Ringing in the ears as if she would faint. 280. Acute stitch-like
pain in the left side, preventing her from turning about in bed. The hair
in the axilla sticks together.
_Eighteenth day._—Heaviness at the vertex. Disturbed sleep. Pain at the
stomach and redness of the face after breakfast.
_Nineteenth day._—285. Feels well all over. Prickings at the right
internal surface of the sternum.
_Twentieth day._—Sore throat; she is unable to swallow her saliva, in the
evening. Distressing pain in the lumbar region, she cannot keep herself
erect.
_Twenty-first day._—She feels as if a piece of flesh had grown out in
her throat. 290. Lancinating pain in the left iliac region, less in the
right. Good appetite. Is unable to walk erect. Complains a good deal
about her pain in the loins.
_Twenty-second day._—She is waked by a violent shrill cough which last
five hours. 295. The pains in the loins are worse when stooping. Acute
pain as if the sacrum were out of place. The pain in the loins causes
her to cry out; she walks bent forward, at 11. The least movement
causes her an acute pain in the sacro-lumbar articulation. Pain in the
posterior part of the right thigh as if a penknife were thrust in. 300.
Pain in the left gluteus muscle, accompanied by nausea. Sensation as if
something would become detached from the sacrum. She can neither remain
standing nor sitting. Pressure as from an iron bar at the sacro-lumbar
articulation, obliging her to lie down when she feels better. Formication
at the sacrum. 305. Cough as from obstruction of the pharynx.
_Twenty-third day._—Restless sleep. Acute lancinating pain above the
right breast, for two hours, in the morning. Pain as if sprained all
along the vertebral column, and extending down the posterior muscles
of the lower limbs to the heels. The face is dark red. 310. She walks
inclined forwards. Heaviness in the stomach, her dinner does not sit well
on her stomach, at 9 in the evening. Walking is hindered by the pain in
the lumbar vertebræ. Desire for coffee.
_Twenty-fourth day._—Her dinner hurts her all night. 315. Palpitation of
the heart, in the night, three different times. Colic with loud emission
of flatulence. Incoherent dreams. The pain in the loins is less. Twisting
pain through the uterus, at nine in the evening.
_Twenty-fifth day._—320. Itching wakes her at four in the morning. Dreams
about a witch, actors changing to yellow and black. Sense of spraining in
the right groin. Slight nosebleed, at six in the evening. Thick urine,
with appearance of white mucus some time after standing.
_Twenty-sixth day._—325. Dreams about fire, then a comedy. The urine
continues to show white flocks after standing.
_Twenty-seventh-day._—Slight nosebleed after supper. Violent itching at
the labia majora, at two.
_Twenty-ninth day._—Hard, difficult and large stool.
_Thirtieth day._—330. Dreams about a revolution, about a city being
destroyed by fire and the sword. Sour eructations exciting her cough.
Smarting and itching at the vulva, at two in the afternoon.
_Thirty-second day._—Canine hunger at dinner. Acidity, bitterness and
regurgitations after dinner, 335. Hard and large stool. Difficult,
fragmentary stool. Painful stool, making the tears rush to her eyes; the
sclerotica becomes red in consequence of the efforts she is obliged to
make. Soapy pale-yellow urine. Colic along the large gut, at nine in the
evening.
_Thirty-third day._—340. Pulling at the stomach, at two in the morning.
Mouth dry. Large, dry, hard, difficult stool. Stool breaking off after
one half is expelled. Pain and smarting at the rectum, caused by the
violent efforts required to expel the stool. 345. Not disposed to
work, at eight in the evening. Irresistible drowsiness. Turbid urine,
of a dingy-yellow, and covered with an oily pellicle. Dreams about
persecutions. Stitches during sleep as though needles were stuck in the
spinal marrow; this wakes her. 350. Starting during sleep. Dry mouth with
tearing sensation in the chest, at two in the morning. She rises in the
night, imagining that thieves are hidden behind the curtains, but she
dares not look behind and begs somebody else to do it.
_Thirty-fourth day._—Restless sleep. Anxiety on waking. 355. Cracked
tongue, in the morning. Violent palpitations and pulsations with
sensation as though the heart were turning about very briskly. The
flatulence presses on the uterus. Hard, dry, large stool, expelled with
difficulty, and causing the tears to rush to her eyes. Regurgitations and
eructations at three. 360. Noisy flatulence, at nine in the evening.
_Thirty-fifth day._—Light sleep. Hoarseness on waking. White-coated
tongue. Desire for liquor and oranges.
_Thirty-sixth day._—365. Dry cough day and night.
_Thirty-seventh day._—Dry cough on waking. Burning in the hand and all
over. Hard and tense pulse. Tongue white in the middle and red at the
tip. 370. Pain at the vertex. Sensation as of water splashing in the
head. The posterior cervical muscles are stiff. Scarlet-redness of the
cheeks. Headache aggravated by work. 375. In bed the sweat smells like
potatoes. Tongue very red. Burning hands, with somewhat uneasy pulse.
_Thirty-eighth day._—The breasts have been painful during the whole time
of the proving, the pain is worse when moving the arms, it then seems
to become seated at the external border of the pectoralis major. Feels
chilly all over, cannot get warm, at half past five in the evening. 380.
Scarlet-redness of the cheeks. After dinner, her clothes feel too tight.
Dry cough for six minutes, at half past ten in the evening. Her thoughts
dwell upon her future, which she imagines will be wretched.
_Fortieth day._—Dry cough, in the evening. 385. Dull colic in the lower
abdomen.
_Forty-first day._—Premature menses. Discharge of black coagulated blood.
For five days the menstrual blood has a very fetid smell, similar to
the smell of spoiled fish. Turbid urine of a dingy yellow, depositing a
copious whitish sediment.
_Forty-second day._—390. Burning thirst, as though her mouth were salt.
Twitching of the right lower limb. Sensitiveness of the hairy scalp and
of the roots of the hairs. Tearing at the vertex; she cannot bear the
least covering on her head.
_Forty-third day._—Hoarseness on rising which disappears immediately. The
same hoarseness in the evening, not long.
_Forty-fourth day._—395. Tearing sensation in the throat, with
accumulation of phlegm which it is difficult to get loose. Expectoration
consisting of yellowish lumps. The phlegm seems to cover the whole
anterior portion of the throat. The pain in the throat disappears after
talking and stirring about. Sensitiveness of the hairy scalp, every day;
she feels a pulling in it which does not allow her to bear the comb.
400. In the morning, raising of black coagulated blood. In the morning
she blows bloody mucus from the nose. Nosebleed every morning, from
forty-second to forty-fourth day. She dreams of battles, dead bodies and
an immense pool of blood.
_Forty-fifth day._—She dreams about green men, covered with moss and
living in the water; these men were changed to dogs.
_Forty-sixth day._—405. At dinner, the dishes taste to her bitter as gall.
_Forty-seventh day._—Sensation as of some obstacle in her throat which
she is unable to expel, followed by the expectoration of a small, hard,
yellowish-gray lump. The urine deposits less, though still turbid. When
attempting to sing, violent palpitations of the heart prevent her from
articulating the sound; her breathing is stopped, she feels as though she
would faint. (Her face is scarlet-red.)
_Fiftieth day._—410. Strong palpitations of the heart, with oppression,
and disposition to faint. She is on the point of fainting, a glass of
water brings her to.
_Fifty-first day._—Palpitation of the heart.
_Fifty-second day._—Heat on the malar eminences and forehead, when going
out to the open air. Palpitations of the heart, after supper. 415. The
palpitation was irregular, stopped for a moment, and then reappeared with
redoubled vigor. These palpitations are accompanied by oppressions, less
when lying down. Alternate subcutaneous pulsations or beatings above
the knee-pan, in the two legs. She does not wish to hear anything in
explanation and is out of humor. Red face, and congestion of blood to the
sclerotica.
_Fifty-third day._—420. Palpitation of the heart the whole day. It is
caused by the act of swallowing. The palpitation is instantaneous and
corresponds to the superior portions of the thorax. (Her lower limbs
tremble on account of the hunger.)
ARRANGEMENT ACCORDING TO HAHNEMANN.
EMOTIVE SPHERE.—1. Quarrelsome, irritable mood. Dread of work.
Hypochondriac mood. She wants to enjoy a change of scenery, &c. She
fancies she is miserable, and dwells much on the future.
SENTIENT SPHERE.—5. Crowd of ideas. His attention is easily disturbed by
other things.
HEAD: Heat in the head, evening. Heaviness of the head; in the vertex;
on stooping and then raising the head again. Catarrhal dulness of the
head, especially the forehead. 10. Headache at noon; increased by the
smell of spirits. The head feels too heavy, she has to make an effort to
support it. Pressure above the eyes, on waking. In the forehead: violent
pain, all day; stitching pain; with dulness of the head, and disposition
to fall forwards. Slight beating in the temples. 15. Sensation as if the
hair would be torn out on the vertex.
EYES: Prickling about the lids, the surface of which is red. Spasmodic
contraction and twitching of the left upper lid. Burning in the lids.
Prickling and burning in the eyes. 20. Congestion of the conjunctiva.
Lachrymation on waking.
EARS: Ringing in the left ear.
NOSE: Repeated sneezing, followed by feeble cough. Nosebleed.
FACE: 25. Face hot and red. Mounting of heat to the face, now and then.
Upper lip bleeding, cracked.
TEETH: Swelling of the mucous membrane of the inner margin of the two
incisores. Teeth covered with white mucus.
MOUTH: 30. Dry mouth. Salt taste. Taste of raw potatoes. The mucous
membrane of the velum palati seems to become detached here and there.
Tongue swollen, cracked, early in the morning; coated white or
yellowish-white; or coated white, with red tip, or yellowish along the
median line. 35. Prickling in the right half of the tongue.
THROAT: Inflamed fauces, she is unable to swallow the saliva.
APPETITE: Canine hunger. Food tastes bitter as gall. Great desire for
liquor and oranges.
GASTRIC SYMPTOMS: 40. Eructations followed by rumbling in the stomach.
Sour eructations causing a cough. Acidity, bitterness, and gulping-up,
after eating. Cardialgia after breakfast, dinner, and supper.
STOMACH: Pain in the stomach, with red face, after breakfast. 45.
Spasmodic pains, griping-tearing at night.
ABDOMEN: Pains and working in the bowels, early in the morning.
Painfulness of the abdomen to contact along the median line. _In the
abdomen_: pain after eating; spasmodic pains, as though the bowels became
twisted together; dull pains in the hypogastric region, at night; pain
with chilliness; rumbling: the clothes cause a feeling of tightness.
Emission of flatulence, also with colic. 50. Pain, as if sprained, in the
right groin.
STOOL AND ANUS: Frequent urging to stool. Stool scanty, with straining,
passing off in small, black lumps; she has to strain until tears come;
hard, large, lumpy; with violent burning in the anus and rectum; hard and
large, followed by two liquid stools. Copious, greenish-yellow diarrhœic
stool. Constipation for five days. 55. Violent colic previous to stool.
Alternate protrusion and retraction of the rectum during stool, with
feeling of chilliness in the body.
URINARY ORGANS: Urine reddish, mingled with mucus. Thick urine;
it becomes covered with white mucus after standing; turbid, of a
dingy-yellow, with copious white sediment; turbid, dingy-yellow, covered
with an oily pellicle. Pain in the urethra, after urinating.
SEXUAL PARTS: 60. Weight in the right testicle, the whole day.
Suppression of the menses. Menses smelling of foul fish, mixed with black
coagula. Small pimples and intolerable itching of the labia. Spasmodic
pains striking through the uterus. 65. Burning and itching in the vagina.
WINDPIPE: In the windpipe: tearing, prickling, with cough; tearing, with
phlegm; sensation as of an obstacle, followed by cough and expectoration
of a lump of hard, yellowish-gray mucus. Hoarseness, on walking. Cough,
with expectoration of yellow mucus, at night. Dry cough, day and night.
70. Cough, as from stoppage in the pharynx. Expectoration of lumps of
black blood, early in the morning.
CHEST: Constriction and difficulty of breathing, caused by dryness of the
mouth. Oppression after supper. Tearing in the chest, also with dryness
of the mouth. 75. Sensation, on making the least motion, as though a
hollow body were moving about in the chest quickly and with a noise,
after which she fancies she will faint, early in the morning. Prickling
as from a thousand pins, on the inner surface of the sternum. Violent
stitching pain above the right breast. The mammæ are painful, especially
when raising the arm. Congestions to the chest. 80. Acute pain in the
left side, like a stitch. Painful stitches in the right side. Palpitation
of the heart, for moments; at night; when lying; when raising one’s-self;
as though the heart would turn; with fainting feeling; with oppression of
the chest (less when lying); irregular (after eating).
BACK: Violent beating in the spine, early, when lying. Prickling
sensation in the spine, during sleep, waking her. 85. Stinging pain in
the large dorsal muscle, right side, when drawing breath. Burning and
painful sensation on the fifth dorsal vertebra, caused by the friction
of the clothes. Sensation of weariness in the whole back. Stiffness in
the muscles of the back. Sense of weight in the back part of the neck.
90. Sensation as if something on the os-sacrum became detached. Pain at
the sacrum, when walking or touching the part. Tingling at the os-sacrum.
Beating in right shoulder. Prickling in the psoas-muscles. 95. Violent
beating in the loins. Pain in the lumbar vertebræ, impeding walking.
Intolerable pain in the lumbar region, obliging her to walk bent.
UPPER EXTREMITIES: Feeling of weariness in the muscles, posteriorly.
Pain as if sprained, in the right upper arm, after leaning on the elbow.
100. Beating in the middle portion of the triceps brachealis. Heat in
the hands. Stinging in the left little finger. Beating in the right
ring-finger.
LOWER EXTREMITIES: Acute pains in the hip-joint, caused by the least
motion. 105. Painful pressure on the hip-joint, as with an iron bar,
compelling her to lie down. In the left gluteus muscle: beating; pain,
accompanied by loathing. Lancinations in the posterior part of the right
thigh. Weary feeling in the muscles of the right side, after walking.
Feeling of dislocation in the hip-joint, with pain in the womb, after a
slight exertion. 110. Shooting pain in the posterior and inferior femoral
muscles, when bending the knee. Beating in the internal femoral muscles.
Alternate heating and throbbing above the patella, in both limbs. Pain as
if sprained, in the whole of the vertebral column, striking through the
posterior parts of the thigh, and extending down to the heels. Drawing
pain in the posterior part of the right lower limb, from the gluteus
muscle down to the heel.
GENERAL SYMPTOMS: 115. General and partial debility. Debility, she
is about to faint. Weariness in all the limbs, on waking. Pain as if
bruised, in bed, preventing her from stirring. Cold water causes a sense
of oppression.
SKIN: 120. Small pimples on the back; causing a violent itching. Small
red pimples on the cheeks. The skin in the face peels off a little.
SLEEP: Irresistible drowsiness. Very sleepy in the evening. 125. Restless
sleep. Starting from sleep, as in affright. Sleepless. Confused dreams,
about fires, revolution, corpses, thieves, &c. Amorous dream. 130. He
dreams that he is to dress or draw the body of a drowned person, but is
prevented in consequence of the body falling all the time on the clothes
or paper. Dreams about men who become transformed to talking animals. He
dreams that his hands are cut to pieces. He dreams that he is falling
from a steeple. 135. She dreams that she is eating human flesh. She
dreams that she is swimming in a river, and that she cannot get out of it.
FEVER: Chilliness and sensation of internal coldness. Coldness, with
chattering of teeth. Repeated chilly creepings through the whole body,
in the evening. 140. Feeling of coldness all over, she is unable to
get warm, her cheeks being very red, in the afternoon. Heat all over,
with sweat. Violent paroxysms of heat, suddenly passing through the
whole body, and proceeding from the vertex. Alternate burning heat and
chilliness, at night, in bed. Exhalations from the skin, when performing
the least work. 145. Sweat all over, early in the morning, in bed. Cold
night-sweat. The sweat smells of potatoes, in bed. Pulse irritated;
irregular; hard and tense.
PLUMBAGO LITTORALIS (NOBIS).
P. LIT. PICAO DA PRAIA.
This is a creeper, inhabiting the shores in the bay of Rio Janeiro. Its
stem is herbaceous, rounded, covered with short and rather stiff hairs.
Its leaves are simple, opposite, gradually tapering to a short channelled
petiole adhering to that of the opposite side, and forming tufts at
certain intervals whence arise adventitious roots. They have a smooth,
trapezoid, coarsely intended limb. The flowers form little axillary
heads, with from 15 to 20 flowers each, arising from an involucre with
five divisions and supported by a somewhat filiform pedicle. Calix
tubulous, monophyllous, with five teeth, and much shorter than the
tube of the corol. The corol is monopetalous, of a yellowish white,
tubulous, puffed up at its extremity, with five reflexed divisions, and
five stamens with bilocular, connivent anthers which are longer than
the corol. Ovary one-celled, flat at the top, whence proceeds a slender
style, terminated by a glandular stygma which is longer than the
stamens. Fruit monospermous, elongated, with a crustaceous integument
which is covered with a number of stiff hairs that are bent over, and
which presents irregular longitudinal furrows. The root is perennial and
ramose. We employ the leaves.
_First day._—1. Weakness of the joints of the lower extremities,
immediately. Vertigo. Slight pain in the right side of the neck, for five
minutes. Body and head are very warm. 5. Cold extremities. Violent sexual
desire at 11, disappearing afterwards during the remainder of the day.
_Second day._—Headache in the morning. Pain in the sides of the chest.
Weakness of the lower limbs. 10. Aversion to every thing. Taciturn.
Acute pain in the left ear, for some minutes. Hot face, with sickness at
the stomach. Passing pain in the left arm. 15. Passing pain in the left
lower limb, for ten minutes. Very drowsy after noon. Headache after a
walk. Acute pain in the left lower limb, in the evening. In the evening,
pain in the limbs. 20. Pain in the head. Internal heat. At night, very
hot internally. Pulse hard and small. Passing and lancinating pains in
various parts. 25. Lancinations in various parts of the head. Lancinating
pain in the kidneys; the parts were all painful as if pricked. Pain at
the right shoulder. Painful burning pricking at the right shoulder.
Catarrhal sore throat. 30. Frequent and scanty flow of saliva. Passing
pains at the neck. Constant pain in the head. Slight sense of heaviness
at the stomach. Sense of chilliness at every motion. 35. Vertigo for 3
or 4 minutes, after eating. Heat in the eyes. Sensitive smell all day.
Constant headache, especially in the forehead. Pain in the left lumbar
region. 40. Heaviness of the head, with vertigo. Drowsy after 9. No
stool, red urine.
_Third day._—Pain in the right lower limb, in the morning. Pain at the
neck. 45. Heaviness of the head and on the eyelids. Taciturn. Sad.
Extremely languid. Pricking in various parts of the thorax. 50. Unable
to lean on an arm, on account of the pain in the thorax. Pain in the
temples. Weak stomach. Painful palpitation of the heart. Heat in the
limbs. 55. Hot arms with cold hands. At 9 in the evening, hard and small
pulse, pain in the right lower limb, all day. Vertigo. Heaviness of the
head. Drowsy. 60. Heat in the eyes. Passing pains in various parts of
the trunk. Passing pain at the humerus. Constant pain at the right hip
and lower limb. Passing pains at the neck. 65. Sexual desire as above.
Headache. Internal heat, coming and going momentarily. Pain in the ribs
when bending forward; feeble pulse. Pain and constriction of the throat.
70. After a walk, heat in the head lasting all day. Pains here and there,
which seem to shift. Red urine. Excessive heat about the head.
_Fourth day._—Aversion to every thing, in the morning. 75. Pain in
the neck. Pain at the back. Headache. Heat in the face. Pain in the
stomach. 80. Pain at the heart. Pain in the chest when straining.
Pain at the humerus when lifting any thing. Slight headache above the
brows. Palpitation of the heart. 85. Agitated pulse. Ulceration of the
commissure of the lips. Constant pain in the iliac region. Milk-colored
spittle. Easy discharge of urine. 90. When drawing breath, pain below
the last false ribs, left side. The same pain on the right side, less
lasting. Stool hard, inodorous. Headache, at night. Pain, with difficult
breathing. 95. Little saliva. An old pain in the chest is worse.
_Fifth day._—Profuse saliva in the morning. Inflammation and lachrymation
of the left eye. Lips dry and cracked at the corners. 100. Heaviness at
the stomach. Extreme languor. Hot fever, vertigo, uneasy pulse. Acute
pains all over for three hours. Pain in the ribs and at the nape of the
neck, in the evening. 105. Violent pain in the eyes. Frontal headache.
Taciturn for some time. Painful stitch in the region of the heart.
Stomach-ache. 110. Pains in the joints hindering movement.
_Sixth day._—Stomach-ache. Pain in the back, while sitting. Languor
and general prostration. Profuse saliva. 115. Bitter mouth. Headache.
Pain here and there. The right lower limb is always painful. 120.
White-colored spittle.
_Seventh day._—Pain in the belly. Pain at the right shoulder. Frightful
dreams, about dead bodies. 125. Pain in the forehead. Heaviness in the
stomach.
_Eighth day._—Pain in the joints. Pain at the right ribs. Pain in the
forehead. 130. Slight pain at the right shoulder. Pain in the lower
limbs. Passing pains above the right ear.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: 1. Vertigo after eating. Vertigo. Taciturn. Excessive heat
about the head. 5. Dartings in the head. Pain in the temples. Frontal
headache. Sensitive smell, all day. Acute pain in the left ear. 10. Heat
in the eyes. Inflammation and running of the left eye.
GASTRIC, &c.: Profuse saliva. Ulceration of the commissure of the lips.
Milky spittle. 15. Bitter mouth. Aversion to every thing. Painful
constriction of the throat. Sore throat. Heaviness at the stomach. 20.
Pain in the iliac region. Pain in the kidneys as if pricked. Pain below
the false ribs when drawing breath. Costiveness with red urine. Violent
sexual desire.
CHEST, &c.: 25. Pain at the right ribs. Prickings in the chest. Pain in
the chest, on which account he is unable to lean on the arm. Pain in
the sides of the chest. Painful stitch in the region of the heart. 30.
Pain at the heart. Palpitation of the heart. Passing pains at the neck.
Pain in the back. Pain at the right shoulder. 35. Pain at the humerus
when lifting any thing. Burning pricking at right shoulder. Weakness of
the joints of the lower limbs. Weakness of the lower limbs. Drowsy. 40.
Dreams about dead bodies. Hot arms with cold hands. Internal heat, coming
and going. Sense of chilliness when stirring. Heat in the limbs. 45. Very
hot, internally, at night. Pulse hard and small. Prostration. Darting
pains here and there. Acute pains all over, for three hours. 50. Pain in
the joints.
SOLANUM OLERACEUM. (VELLOZ.)
SOL. OL.—PORTUG.: GYQUIRIOBA, JUQUERIOBA.
This is an herbaceous plant with a creeping and somewhat ligneous,
cylindrical stem, the upper branches being covered with short and
crooked thorns. The leaves, of a dark green, are alternate, irregularly
pennate; the folioles are long, lanceolate, almost sessile on a thorny
spike; there are from 7 to 9, those at the top being the largest. The
flowers are supported by ramose pedicles, which do not grow out of axils;
calice campanulate, with five divisions; corolla of a greenish white,
monopetalous, with five equal, rotaceous, somewhat reflexed divisions
alternating with those of the calix. Five stamens with erect, converging
and bilocular anthers; their filaments are short, with the exception of
one, which is longer than the rest. Ovary oval, surmounted by a filiform
style. Berry spherical with two compartments, of a dark green, with white
spots. This solanum grows on the shores around Rio Janeiro, in damp and
shady places. We employ the flower.
1. Scanty urine. Short-lasting menses. Toothache at night. Acute catarrh.
5. Suffocating cough. Pain in the face. Toothache. Pain and swelling
of the face and throat, with inflammation. No sleep for two nights. 10.
Stye on the right lower eyelid. Swelling of a cervical glands. Continual
redness of the face. Difficult digestion. Pain at the internal canthi
of the eyes. 15. Inflammation of the left upper eyelid. Tickling at
the lower limbs. Pustules all over, first white, then red, with an
intolerable itching now and then. Lancinating pain in the stomach not
lasting long. Sense of chilliness in the left side of the chest, after
drinking. 20. Violent pain in the left cheek, spreading over the whole
face. Discharge of fetid yellow mucus from the left nostril. Sadness.
Irritable. Drowsiness with headache. 25. Herpetic eruption at the ankle.
Nettle-rash fever. _Sore throat._ Itching. Ptyalism. 30. No appetite.
Tongue coated white. No sleep. Drowsy for four hours in the middle of
the day. Discharge of white mucus from the vagina. 35. Swelling of the
mammary glands with profuse effusion of milk, on the second day. Drowsy
all day. Shortly after taking the drug the breasts of a negro-woman of 60
years began to swell and discharged a quantity of milk.
ARRANGEMENT ACCORDING TO HAHNEMANN.
1. Sad. Irritable. Toothache. Pain in the face, also with swelling of the
face and throat, and inflammation. Redness of the face. 5. Pain in left
cheek, spreading over the face. Stye on right lower lid. Inflammation of
left lower lid. Pain at the inner canthi. Discharge of fetid yellow mucus
from left nostril. 10. Difficult digestion. No appetite. Tongue coated
white. Chilly feeling in left chest, after drinking. Sore throat. 15.
Ptyalism. Lancinating pain in the stomach. Scanty urine. Short-lasting
menses. Discharge of white mucus from the vagina. 20. Swelling of the
mammary glands, with discharge of milk. Tickling at the lower limbs. No
sleep. Drowsy with headache. Itching pustules all over, first white, then
red. Herpes at the ankle. Nettle-rash with fever.
PAULLINIA PINNATA.
PAUL.—PAULLINIA TIMBO (VELL).—PORTUG.: GUARATIMBO, TIMBO-SIPO, CURURU—APÉ.
This beautiful liana is commonly found in the woods of Brazil; its stem,
of a flexible and tenacious wood, furnishes slender, slightly pubescent
branches with deep parallel furrows. The leaves are alternate, with
winged petioles; they are composed of five folioles which are almost
sessile, oval-lanceolate, crenulate, irregularly bizugate. The flowers
are small, in spikes, situated on axes that are accompanied by leaflets
arising from the axillæ of the leaves. Calix with five folioles, corolla
with four petals, alternating with the folioles of the calix; eight
stamens; ovary with three uni-ovulate chambers. Capsule pear-shaped and
sharp, divided at its superior part in three tubercles. Root with long
fasciculate branches which are a little hairy at their extremity. We
employ the fresh root.
_First day._—1. Loathing, tongue thick and doughy, in a few minutes. She
dreams about a leprous woman, which disgusts her.
_Second day._—Very chilly. Colic followed by a reddish diarrhœic stool
mixed with slime. 5. Headache as if the head were covered with a cap
of lead on which one strikes. Loathing of food. Desire for dainties.
Frequent and ineffectual desire to urinate. Pain of the soles in walking,
increased by pressure. 10. Lancinating pain in the heel.
_Third day._—Sensation in all the limbs as if bruised. Dizzy, her head
inclines forwards. The feet feel numb, after going up-stairs. The arms,
chest and head, except the ears, are very cold. 15. Desire to vomit. Her
tongue feels as if it were as thick as a finger. Burning when urinating.
She likes to remain quiet and shut up. Dreams about a leprous patient
whose sores bleed. 20. Her chest feels as if it would open, with a
cracking noise. Stitch under the right eye.
_Fourth day._—Shuddering on rising. Sharp pain during stool, as if a
penknife had been plunged into the abdomen. Prickling at the left eye,
which weeps and is very much inflamed. 25. Redness of the sclerotica.
Buzzing in the left ear for 15 minutes. Pain in the groin as if the
nerves were cut. Crampy pain in the left side of the hypogastrium.
Itching and tingling in the throat. 30. Pain at the eyebrows meeting from
opposite side at the root of the nose. Heat in the soles. Oppression and
burning in both sides of the chest. Pressure in the hypogastrium. Pain
as if a string had been strung round the hypochondria. 35. Intolerable
itching, with sense of burning in the chest. Beating in the temple
and above the left eye. Pain at the navel as from a penknife. Painful
sensation as from an iron bar, compelling the head to incline forwards.
Constant ennui. 40. Loathing at the sight of food. Desire for the taste
and smell of coffee. General lassitude.
_Fifth day._—Pain in the lower limbs, which become stiff by walking.
Cramp in the palm and fingers of the left hand, extending to the arm.
45. Violent pain in the side as if a stone were pressed in. Itching and
suppuration behind the head.
_Sixth day._—Hammering in the vertex, reverberating in the temples.
Restless sleep. She dreams that she wishes to open her chest in order to
look into it. 50. Pressure at the chest and sides, as if pressed upon by
iron sheeting, and then pierced with penknives, causing an acute pain.
Nausea. Lancinating pain in the left nipple, as if a penknife were thrust
in, at regular intervals. Sawing pain as if the cartilage of the left ear
were cut; this pain extends to the left side of the neck. Prickings as
from a thousand needles in the left thigh, high up, for several minutes.
_Seventh day._—55. Pressure as from an iron band around the waist; and
stitches in the upper part of the thorax, worse during motion. Crampy
pain in the left hand, for a moment. Sensation, while talking, as if a
stone were burying itself in the stomach. Pain as if a knife were plunged
into the right side.
_Eighth day._—She dreams that a scabby dog full of sores is walking
towards her; she took hold of the dog, who bit her; then she uttered loud
cries, in the midst of which she awoke with a severe pain in the chest.
60. She feels bruised all over. Headache as if her head would split.
Lachrymation, especially of the left eye. Very hungry at dinner. Stabbing
sensation in the ovaries, for a moment. 65. Painful stitches in each side
of the abdomen.
_Ninth day._—Burning in the chest. Pain at the right ankle, as if
sprained. Tingling in the throat. Pain in the loins as if bruised; she is
unable to raise herself after stooping. 70. Pain at the right shoulder,
disappearing by friction. Numbness in the shoulder. Intense itching under
the arm.
SECOND PROVING.
_First day._—Sense of scraping in the throat. Heat in the front part of
the chest. 75. Short breathing. Passing in the region of the liver. Acute
pain at the left wrist. Rumbling in the right hypochondrium. Pain in the
left hypochondrium. 80. Pain in the right parietal region, as if pressed
from within outwards. Internal trembling in the umbilical region and the
left hypochondrium. Pain in the whole abdomen, worse when touching it.
Pain at the heart, at 2 in the afternoon. Lancination in the præcordial
region. 85. Chilliness, first of the upper part of the body, and then
all over. Alternate heat and chilliness in the face. Dry mouth. Rough
tongue with sensation as if larger. Obnubilation. 90. Lancination, as
after chewing cloves; a constant symptom. Numbness of the arms. Trembling
of the lower limbs. In walking, she feels as though she were walking
backwards. Lazy, not disposed to work. 95. Desire to lie down. Rough
voice. Yellowish, bitter, difficult and tenacious expectoration. No
appetite. At 6, the pain at the heart extends to the last ribs. 100.
Acute pain in the middle of the head, on the right side. Headache, on
the left side. Out of breath, with desire to vomit. Pain above the eyes,
penetrating to the brain. Pain at the left breast. 105. Pain in the right
side of the chest, at half past 7 in the evening. Melancholy. Pain in the
right temple. Weakness and heaviness in the lower limbs. 110. Numbness in
the sole of the right foot and at the knee. Pain in the shoulder-blades.
Red spots in the face and on the chest. Shooting in the jaws. Sadness and
drowsiness all day.
_Second day._—115. Desire to vomit on waking. Pain at the left groin, at
8. Weak feeling in the chest. Pain in the left temple. Pain in the left
arm, extending to the back. 120. Pain in the middle of the head as if a
nail were thrust in. Itching in the hand and fingers, obliging one to
scratch until the skin is off. Deep ennui. Acute pain in the right side
of the chest, at 4 in the afternoon. 125. Pain in the left thigh. Pain in
the right teeth. Contusive pain in the region of the liver, in touching
the right ribs; worse when walking. Chilliness all over in the evening.
130. Pain near the right elbow; at 9 in the evening.
_Third day._—Acute lancinations under the right arm. Pain at the neck.
Lancinations in the left side. Heaviness of the head; with pain in the
right temple. 135. Heat in the face. Lancination under the right breast,
at one o’clock. Dull pain in the left ear, at 2. Lancinations in the
liver. Headache at night.
_Fourth day._—140. Pain in the whole abdomen. Extraordinary desire for
coffee and fruits. Constipation, for two days. Toothache continued. Pain
under the right arm. 145. Pain at the internal part of the right arm.
Lancinations in the right side of the chest, at 4 in the evening.
_Fifth day._—Dreams about dead persons. Vision of dead persons. Headache,
in the region of the right temple. 150. Pain from the arm to the chest,
at 8 in the morning. Heat in the chest, around the breast, which feels
as if pressed together by an iron band. Staggering gait. Bitter mouth.
Profuse saliva. 155. Shortness of breath. Pain in the left arm when
stretching it. Pain in the neck, less in the open air. Pain in the right
side of the chest, below the clavicle and the right axilla, at 6 in the
evening. No sleep.
_Sixth day._—160. Diarrhœa. Pain in the right side of the chest.
Rheumatic pain in the knees. Pain around the navel. Pain in the chest.
165. Headache all day. Desire to walk. Lancinations in the splenetic
region, at noon. Pain in the right shoulder, at one o’clock. Chilliness,
at 3. 170. Shuddering with drowsiness and arthritic pains. Lancinations
in the right side of the chest, at half past 3. Lancinations in the right
breast, at 6 in the evening. Heaviness of the head and forehead.
_Seventh day._—Short breathing. 175. Pain under the sternum. Pain in the
right wrist. Pain in the joints. Pain in the right ear. Blood-streaked
saliva. 180. Headache in the evening, with inability to stoop. Violent
cough, with inflamed throat. Fear of being phthysicky. Sad dreams.
_Eighth day._—When drawing breath, the chest feels as if opened. 185. Dry
and short cough.
_Ninth day._—Headache in the morning. Weariness of the lower limbs. Pain
in the left side of the chest, as far as the arm, as if the parts were
scratched.
_Tenth day._—Pain around the umbilicus. 190. Lancinations in the right
side of the chest. Lancinations in the right eye, with lachrymation. Heat
all along the back. A good appetite all day. Dreams about dead persons,
with tears on waking. 195. Dry and short cough.
_Eleventh day._—Oppression on the chest. Dry cough. Pain in the right
side of the chest. No appetite. 200. Ulceration at the lower limbs, with
itching.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL AND MORAL: 1. She likes to be alone and quiet. Ennui. Melancholy.
Dizzy, her head inclines forward. 5. In walking she imagines she is
walking backwards. Staggering gait. Vision of dead persons.
HEAD: Headache in the evening, with inability to stoop. Heaviness of the
head, with pain in right temple. 10. Acute pain in middle of the head.
Pain in head as from a nail. Pressing pain from within outwards, in right
parietal region. Splitting headache. Beating in the temple and above
the left eye. 15. Pain as from an iron bar compelling the head to stoop
forward. Hammering in the vertex. Headache as if the head were covered
with a cap of lead on which one strikes.
EARS, EYES, &c.: Dull pain in left ear. Sawing pain in the cartilage of
the left ear, extending to the neck. 20. Buzzing in left ear. Alternate
heat and chilliness in the face. Shooting in the jaws. Pain in right
teeth. Darting in right eye, with lachrymation. 25. Pain above the eyes,
penetrating to the brain. Stitch under the right eye. Prickling in left
eye, which runs and is inflamed. Pain at the eyebrows, towards the root
of the nose.
GASTRIC: Rough tongue, with sensation as if larger. 30. Bitter mouth. Out
of breath, with desire to vomit. Loathing at the sight of food. Desire
for coffee. Desire to vomit. 35. Loathing, with tongue thick and doughy.
Desire for dainties. Itching and tingling in the throat. Scraping in the
throat. Yellowish, tenacious expectoration. 40. Sensation, while talking,
as if a stone were burying itself in the stomach.
ABDOMEN: Pain around the navel. Lancinations in the splenetic region.
Contusive pain in the region of the liver. Pain in the region of the
liver. 45. Pain in abdomen, worse when touched. Pain in right side, as if
a knife were plunged in. Painful stitches in each side of the abdomen.
Constrictive pain round the hypochondria. Cutting pain at navel. 50. Pain
in the side as if a stone were pressed in. Crampy pain in left side of
hypogastrium. Pain in the groin as if the nerves were cut. Colic followed
by a reddish diarrhœic stool. Constipation. 55. Diarrhœa. Sharp pain
during stool, as from a penknife. Ineffectual desire to urinate. Burning
when urinating. Stabbing sensation in the ovaries.
BRONCHIAL: 60. Blood-streaked saliva. Cough with inflamed throat.
CHEST: Her chest feels as if it would open, with cracking. Itching and
burning in the chest. Oppression and burning in the sides of the chest.
65. Burning in the chest. Lancing pain in left nipple. Pressure at the
chest and sides as from iron sheeting, followed by sensation as if
pierced by a penknife. Acute pain in the right side of the chest. Weak
feeling in the chest. 70. Pain at the right breast. Dartings in the right
breast. Pain under the sternum. Pain under the right clavicle. Shortness
of breath. 75. Heat around the breast which feels compressed. Dartings in
right side of chest. Scratching pain in left side of chest. When drawing
breath, the chest feels as if being opened. Pain at the heart. 80.
Lancination in the præcordial region.
BACK: Heat along the back. Pain in the neck. Pain in the shoulder-blades.
EXTREMITIES: Numbness in the shoulder. 85. Numbness of the arms. Itching
under the arm. Dartings under the right arm. Pain from the left arm to
the back. Cramp in the palm and fingers of the left hand. 90. Pain in
the lower limbs, which become stiff by walking. Prickings in left thigh,
high up. Trembling of the lower limbs. Numbness in right foot and knee.
Rheumatic pains in the knees. 95. Pain at right ankle as if sprained.
Lancing pain in the heel. Pain of the soles in walking. Heat in the
soles. The feet feel numb after going up-stairs.
FEVER, SLEEP: 100. Shuddering with drowsiness and arthritic pains.
Chilliness. Shuddering on rising. Chilly. Restless sleep. 105. She
dreams that a scabby dog is walking towards her; it bit her, and she
cried out. She dreams that she wishes to look into a chest. Dreams about
a leprous woman.
CUTANEOUS, GENERAL: Ulcers at the lower limbs, with itching. Red spots
in the face. 110. Itching and suppuration behind the head. Pain in the
joints. Distressing itching in the hand and fingers. Desire to lie down.
Bruised all over. 115. Lassitude. Sensation in the limbs as if bruised.
BLATTA AMERICANA (LAM.)
BLATTA.—KAKERLAT AMERICANA (SAR.) PORTUG.: BARATTA.
The blatta americana, which is very common in Brazil, where it inhabits
human dwellings, is an orthopterous insect, with an elongated, oval,
rather flat body, from 12 to 16 lines in length, of a brown-red which
becomes paler under the belly. The prothorax is smooth, shining, of an
ochre yellow, with two large brown spots, which are sometimes united in
one. In the male the elytræ reach beyond the belly by a few lines; in
the female they are a little shorter. They are marked with numerous
longitudinal streaks which bifurcate near the dotted margin terminating
the elytræ. The wings are striate and reticular, of the length of the
elytræ. The antennæ which are longer than the body, exhibit at their base
a small yellowish point. The feet are provided with black prickles and
terminate in a tarsus with five articulations.
We triturate the whole insect, if possible alive, for 15 minutes; after
which we take two or three grains of this paste and rub them down with
100 grains of sugar of milk in order to obtain the first trituration.
_First day._—1. Aching pain in the temples. Numbness and heaviness of
the head. Formication in the toes, at 7 in the morning. Pain shifting
from the back to the shoulder-blade. 5. Prickings in the left side of
the neck. Heat in the urethra when urinating. Stitch as by a fly, in
the corner of the left eye, at 10 in the morning. Sense of weariness in
the bends of the knees. Yellowness of the face. 10. Yellowness of the
sclerotica. (When the prover had the jaundice, for which the blatta is
considered empirically as a specific, he felt a number of pains which
have been reproduced in this proving, such as general prostration,
weariness, &c.) Frequent yawning, watery discharge from the nose.
Lachrymation. Passing bloating at the pit of the stomach. 15. Drowsy in
the afternoon. Acute pains in the temples, every now and then, at 4 in
the afternoon. Chill and shuddering for half an hour. Pain at the right
leg, from the toes to the knees. Slight colic. 20. Pain in the back,
right side. Shuddering; sense of heat and slight moisture all over. Pain
in the transverse colon, duodenum and pit of the stomach. Pain at the
left little toe. Pain in the right side of the chest. 25. Shuddering for
one hour. The pain in the temples continues. Yellow color of the urine,
increasing more and more. Salt saliva.
_Second day._—Pain in the temple, with lancinations now and then. 30.
Sense of weariness in the bend of the knee. Pain in the feet, here and
there, and sometimes in the sole. Lazy. Frequent yawning. Acute pain
in the chest, afternoon. 35. Cramp in the right leg. Weary when going
up-stairs. Violent pain in the chest, with want of breath. Urine of a
bright-yellow, albuminous. The proving was interrupted by an accident.
HAHNEMANN’S ARRANGEMENT.
1. Aching in the temples. Numbness and heaviness in the head. Acute
pains in the temples. Pain in the temple, with lancinations now and
then. Stitch in canthus of left eye. Yellowness of the sclerotica.
Lachrymation. Bloating at the pit of the stomach. Pain in the transverse
colon. Heat in the urethra when urinating. Bright-yellow, albuminous
urine. Acute pain in the chest, afternoon, also with want of breath. Pain
shifting from the back to the shoulder-blade. Pricklings in the left side
of the neck. Formication in the toes. Sense of weariness in the bends
of the knees. Pain in the feet, here and there. Chill and shuddering.
Shuddering, with sense of heat and moisture all over. Weary when going
up-stairs.
DELPHINUS AMAZONICUS.
DELPH. DELPHINUS GEOFFROYI (DESM.) PORTUG.: PEIXE BOI.
This dolphin is from 9 to 10 feet long; its body is large and
cylindrical, of a brownish-gray color above and a pure white below. Its
jaws, of equal length, are long, narrow, linear, armed on each side with
26 large conical, somewhat rugose teeth, with wide crowns. Its forehead
is bomb-shaped, the eyes a little above the commissure of the lips. The
pectoral fins are of considerable size, brownish at their extremities,
and placed very low; the dorsal fin is elevated and semilunar. This
dolphin, as its name shows, inhabits the mouth of the Amazon. It has a
thick and fibrous skin, which we employ in medicine.
(Before trying the drug, the prover had paroxysms of cough with
suffocation, during which a hernia protruded with much force.)
_First day._—1. Slight pain at the navel, after five minutes. Feeling of
a quantity of air in the stomach, with grumbling in the abdomen. Pain at
the loins, on rising in the morning. Eructations. 5. Violent smarting and
excoriating pains, shifting from the right thigh to the heel, then to
the right shoulder; these pains are aggravated by contact. In moving the
right toes, the bones cracked as if notched. Quickly passing pain at the
right eyebrow (when coughing, the hernia did not protrude any longer with
so much force.)
_Second day._—Doughy mouth. 10. He has not been troubled with
suffocation and the cough is less. Headache. Violent colic with soft and
strong-smelling stools. Pain in the loins. Hard abdomen, especially on
the right side, where he feels like a ball which is painful when touched,
in the evening. 15. Dry lips.
_Third day._—Restless and disturbed sleep. (Cough continues.) Pain in
the loins. The hardness in the abdomen has shifted to the left side. 20.
Bleeding from the left nostril. (Before taking the drug he bled from the
right nostril.)
_Fourth day._—Acid stomach. (Cough with suffocation.) Erections, with
sexual desire. Itching at the anus as from worms. 25. The bones of the
thorax are affected with rheumatic pains.
AMPHISBŒNA VERMICULARIS.
AMPH.
This species moves either backwards or forwards, as occasion may require,
and is quite frequent in the woods of Brazil. Its body is cylindrical,
from two feet to two and a half long, terminated by a very obtuse
tail. It has no scales properly speaking, but its skin is divided into
quadrilateral compartments disposed in rings round the body; 228 on the
trunk and 26 on the tail. The lower lip is divided into six long and
narrow plates; the head is small, rather sharp, protected by scutellæ,
and not distinguished from the neck. It has small eyes; the jaw is
not dilatable, the teeth are conical, bent, unequal and distinct from
each other; the nostrils are on the sides, and pierced in a single
naso-rostral plate. The amphisbœna is of a brownish color above, and
a pinkish-white under the belly. The poison was taken from the living
animal by cutting off part of its jaw, which was triturated immediately.
1. Debility. Sadness and lassitude in the morning, which leaves one
while walking. Tender sadness which disposes one to be gentle and meek.
Violent pain in the whole of the vertebral column, worse when walking,
moving the arms or stooping. 5. Painful and large pimple on the left
side of the upper lip, suppurating. Acne rosacea miliaris (a dry itch
cured), covering extensive ellyptical spots; after the eruption healed, a
furfuraceous desquamation took place wherever a pimple had been situated.
Wakes at midnight, for ten consecutive nights. Disturbed sleep.
_Fifteenth day._—Depression. 10. Ennui. Impatience. Weight in the
forehead and parietal regions. Weight at the forehead. Vertigo as if one
would fall towards one side and is then impelled towards the opposite
side by a contrary oscillation. 15. Pain at the inner canthus of the
right eye as if a stye would form. Repeated beating at the right side
of the forehead as if hail-stones fell upon it. Sweat about the head.
Horrible headache, with sensation as if the feet were in the brain.
Dizziness when turning round. 20. Constant twitching at the upper
eyelids, especially the left. Constriction of the right eye as if strung
together with a cord. Shooting pain in the outer angle of the left eye.
Sensation as of a grain of sand in the right eye. Weariness of the
eyes, in the evening, with pain and pricking when looking at the light.
25. Lachrymation and constriction of the left eye. Pain in the meatus
auditorius, as if air were rushing in. Pricklings and heat at the right
malar eminence. Dull pain _in the right lower jaw-bone_. Lancination
and pain all through the right side of the head. 30. Pains in the right
lower jaw, and considerable swelling aggravated by air and dampness.
Swelling of the right lower jaw, worse in the open air. The teeth feel
elongated and set on edge, especially the right lower molares. The
toothache is worse in the evening and afternoon. Chewing is painful,
but the contact of liquids is not painful. 35. Swelling of the tonsils.
Deglutition is difficult, one is not able to swallow saliva. Protrusion
of umbilical hernia. Chilliness and pains at the epigastrium. Tearing
pain at the navel, all day. 40. Suppuration of inguinal hernia. The
hernia is painful, and air is felt in it. Lancination in the navel as
from a stiletto. Constipation. The miliary acne rosacea spreads over
the chest, neck and back, with itching which is worse in the morning and
decreases in the evening. 45. Gradually a white vesicle forms on every
pimple, discharging a clear serum, after which the eruption dries up on
the fifth day. Breaking out of little pimples, especially on the forearm.
Painful swelling of the arm, on the fifteenth day. Cramp in the left leg.
Painless drawing up of the legs. 50. Cramp in the left leg; it remains
behind in walking as if paralyzed.
ARISTOLOCHIA MILHOMENS. (NOBIS.)
ARIST. ARISTOLOCHIA GLANDIFLORA (GOM.)—ARISTOLOCHIA CYMBIFERA (MART.)
SNAKE-ROOT.
A climbing plant with a glabrous stem; leaves alternate, uniformly
cordate, pedati-nerved, with reticulate little veins between the nerves;
they are supported by long petioles, furnished with a large, entire,
reni-form, amplexicaule stipule. Flowers solitary, upon a sulcate
peduncle from four to five inches long. Perianth single, large, of a
yellowish brown, tuberculated, curved, divided into two lips; the upper
lip sharp, lanceolate, and somewhat bent outwards; the lower lip, twice
as long as the other, at first dilated at the base, and expanding into a
large oval disk with undulate borders. The whole flower is covered with
prominent nerves. Stamens six epigynous. Ovary glabrous, surmounted by a
stygma with six short and rounded lobes.
We employ the flower.
_First day._—1. Restless sleep. He dreams that he is neither able to
work, drink or walk. Gurgling at the right frontal eminence, for one
minute. Doughy mouth the whole morning. 5. Thirst. Pain in the right
groin. Numbness of the left leg. Numbness of the lower part of the calf.
Borborygmi in the stomach and bowels. 10. Lancinations in the whole of
the left lower limb. The left leg is red and swollen. The head feels
heavy. Very thirsty, with bitter mouth. No appetite. 15. Stitch in the
ball of the left thumb, at half past three in the afternoon. Torpid
sensation at the vertex. Pricking in the right testicle. Pricking at the
right thigh. Pricking at the lower part of the left leg. 20. Itching
at the inside of the left thigh. Prickings here and there, over the
body. Pain at the ball of the right thumb, at 7 in the evening. Torpid
sensation in the cerebellum. Stitch under the heel. 25. Itching at the
left outer ankle, at 8. Itching at the skin of the prepuce. Crampy pain
at the right inner ankle. Contusive pain at the left pectoral muscle,
which is sensitive to contact, at night.
_Second day._—Restless sleep. 30. He dreams about a sheep and dog covered
with red scarfs; the first was lifted off the ground and seized by the
latter in the middle of the back; the dog was suspended by the back, by
some individual accompanied by a number of persons. Afterwards an intense
sexual dream with emission. Painful stitch under the shoulder-blade, as
after receiving a blow. Sense of embarrassment behind the left inner
ankle. Uneasiness in the thighs, followed by pricking, at 2 in the
afternoon. 35. Contusive pain at the left knee. Lancinations at the
forepart of the left outer ankle, at 7 in the evening. Fulness of the
stomach. Stitching pain at the right thigh. In the morning, the leg is
swollen and violet-colored; it becomes inflamed by walking, and, towards
evening, changes to a blackish red. 40. Loss of appetite. The whole leg
is covered with irregular blackish spots formed by extra-vasated blood.
Urinates more frequently than usual. Burning head. Continual thirst, with
bitter mouth. 45. The lips and gums are excoriated. Complete loss of
appetite. The left leg is painful as if excoriated; the pain shifts to
the right inner ankle, where it becomes more acute.
_Third day._—Lancinating pains at the apex of the heart, which arrests
the breathing all night. The temples are painful to contact, the whole
day. 50. Stiffness of the leg, with inability to stand for a few minutes.
Stitching pain between the shoulders. Dull pain at the lower part of the
lumbar region and at the abdomen. Burning pains at the anus. The lips and
gums are raw as before. 55. Itching above the bend of the right elbow.
Crampy pain in the left tendo-Achillis. Partial numbness around the
ankles. Contusive pain below the left knee-pan, at 3 in the afternoon.
Lancinations in the lower part of the right leg and at the inner ankle,
at half past 3. 60. The upper and lower part of the left arm is painful
to the touch, at half past 4. Painful lancinations at the inner part of
the left knee. Stitch in the articulation of the first phalanx of the
little finger, at 8 in the evening.
_Fourth day._—Pain at the dorsal part of the left index. Colic, followed
by stool the first part of which is soft, the latter diarrhœic, twice in
succession, in the morning. 65. Malaise as if something would accumulate
at the inside of the right leg, above the knee, in the evening and during
part of the night.
_Fifth day._—Difficulty of using the lumbar region. Sensation as if the
skin of the right leg would fall upon the ankles, like a stocking; he
frequently puts his hand there for the purpose of raising the skin again.
Itching at the forepart of the right leg. Pricking at the inside of the
right leg. 70. A difficulty at the lower part of the tendo-Achillis. Easy
stool.
_Sixth day._—Itching at the internal ankle of the left foot. Itching at
the left thigh. Pain above the right inner ankle. 75. Disgusting dreams.
_Seventh day._—Malaise after waking in the morning; he is unable to fall
asleep again; he feels as if something near the ankles inconvenienced
him for several hours. This pain increases towards three, changing
to a contusive pain. The ankles feel swollen. 80. Acute pain in the
sacro-lumbar region. Pain in the right side.
_Eighth day._—Pain at the pit of the stomach. The pain in the legs
continues. Permanent pain above the left inner ankle. 85. Smarting at the
inner and upper right thigh, in the evening. Acute lancination in the
head, evening.
_Ninth day._—Acute lancination in the left side of the head, evening.
_Tenth day._—Violent lancination behind the head. The forepart of the
left leg is painful to contact. 90. Shootings in the cerebellum.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD. Head heavy. The head is burning hot. Throbbing in the right frontal
eminence for a minute. Sensation of torpor at the vertex. 5. His temples
are very sensitive to touch during the whole day. Acute lancination
in the head. Acute lancination in the left side of the head. Severe
lancination behind the head. Shooting in the cerebellum. 10. Sensation of
torpor in the cerebellum.
MOUTH: Mouth pasty through the whole morning. Excoriations of the lips
and gums. Excoriations of the lips and gums as on the second day.
APPETITE: Anorexia. 15. Want of appetite. Complete anorexia. Thirst.
Great thirst with bitterness of the mouth. Continual thirst and bitter
mouth.
STOMACH: 20. Borborygmus in the stomach and intestines. Fulness of the
stomach. Pain at the scorbiculus.
STOOL AND ANUS: Colic, followed by a stool, at first soft, then
diarrhœic, twice in succession. Easy stool. 25. Burning pains at the
anus.
URINARY AND GENITAL: He makes water more frequently than usual. Itching
on the skin of the prepuce. Pricking in the right testicle.
CHEST: Lancinating pain at the apex of the heart which takes away his
breath at night. 30. Bruised pain over the left pectoral muscle, which is
sensitive to the touch at night.
BACK: Painful spot under the scapula, as if from having received a blow.
Sharp pain between the shoulders. Pain in the right side. Uneasiness in
the lumbar region. 35. Dull pain at the lower part of the lumbar region
and in the hypogastrium. Acute pain in the sacro-lumbar region.
SUPERIOR EXTREMITIES: The upper and lower parts of the left arm are
painful to the touch. Itching above the bend of the right arm. Stinging
in the hypothenar eminence of the left hand. 40. Pain in the hypothenar
eminence of the right hand. Pain in the dorsal portion of the left index.
Pricking in the joint of the first phalanx of the little finger.
INFERIOR EXTREMITIES: Pain in the right groin. Lancinations through the
whole extent of the left inferior extremity. 45. The left leg is red and
inflamed. Swelling of the left leg. The leg is swollen and violet-colored
in the morning; it becomes inflamed by fatigue and turns blackish red
towards evening. The whole leg is covered by large irregular patches
formed by extra-vasated blood. Malaise as if something were collected in
the internal part of the right leg above the knee. 50. The pains in the
legs continue. Uneasiness, then pricking in the thighs. Stiffness of the
leg, with impossibility of standing up for a few minutes. Pricking on the
internal surface of the right leg. Smarting on the internal superior part
of the right thigh. 55. Pricking in the right thigh. Acute pain in the
right thigh. Itching on the right thigh. Itching on the internal surface
of the left thigh. The upper part of the left leg is painful to the
touch. 60. Itching on the anterior part of the right leg. Bruised pain in
the left knee. Bruised pain under the left patella. Painful lancinations
in the internal part of the left knee. Prick as from a pin in the lower
part of the left leg. 65. Swelling of the lower part of the calf.
Cramplike pains in the left tendo-Achillis. Uneasiness in the lower
part of the tendo-Achillis. Prick under the heel. Malaise after waking
in the morning; he cannot go to sleep again; he feels as if something
incommoded him about the malleoli for several hours. This pain increases,
becoming a bruised pain. 70. Partial swellings around the malleoli. The
malleoli appear swollen. Feeling as if the lower part of the right leg
had a tendency to fall down upon the malleoli, as a stocking might do; he
often carries his hand there as if to raise it up. Cramplike pain in the
right internal malleolus. Pain above the right internal malleolus. 75.
Lancinations in the lower part of the right leg and internal malleolus.
The left leg is painful as if excoriated; the pain passes to the right
internal malleolus and becomes more acute. Lancinations in the anterior
part of the left external malleolus. Itching on the left external
malleolus. Itching on the left internal malleolus. 80. Persistent pain
above the left internal malleolus. Disagreeable sensation behind the left
internal malleolus.
SLEEP: Disturbed rest. Unquiet sleep. Dreams. Disgusting dreams. 85. He
dreams that he can neither act nor drink nor walk. He dreams of a sheep
and a dog, covered with red scarves; the former, elevated above the
ground, shook his head and was seized by the dog in the middle of his
back; the dog himself was suspended by the back by a man accompanied by
many other individuals. Afterwards, a very amorous dream with pollution.
GENERAL: Prickings in different parts of the body.
RESINA ITU.
ITU.
This rosin which comes to us from the province of St. Paul, is used
empirically for hernia.
_First day._—1. Stupefying pain in the head, worse when stooping. Vertigo
as if one would fall to the right. Earache when the least dampness sets
in, extending to the articulation of the jaw. Numbness at the tarsal
joint, after sitting. 5. Pain in the abdomen, from within outwards.
Sense of chilliness at the hypogastrium, especially in the evening.
_Second day._—Light sleep at night, but continual. Continual hiccough.
Aching pain in the forehead and eyes. 10. Beating in the right temple.
The pain extends to the ear and the articulation of the jaw. Pain on the
left side like wry-neck. Lancination in the forehead, right side. Nausea
worse during motion. 15. Pain in the left hypochondrium, when inclining
forwards.
_Third day._—Violent itching near the sternal extremity of the right
clavicle, followed by a moist tetter, which scatters in six hours.
_Fourth day._—Violent itching at the right arm; it is covered with red
pimples, rounded like pins’ head. The itching ceases in the day-time, but
the eruption lasts all day. Pimples on the left side of the neck; they
itch as much, though less inflamed. 20. Numbness of the legs. On rising
from a chair one is unable to stand straight.
_Fifth day._—Stiffness of the nape of the neck, which prevents one from
raising or inclining the head. Pain at the nape of the neck, penetrating
to the forehead and causing a numbness and heaviness which carries the
head forward. The pimples on the arm and neck scatter gradually.
_Sixth day._—Cramps at the left tarsal joint. 25. Involuntary stools.
_Seventh day._—Sudden report in the ear, with frightful pain extending to
the teeth, for several minutes; this paroxysm recurs four times in the
morning, from hour to hour. Numbness in the tarsal joint every time one
rises from a seat. Profuse painless diarrhœa. Copious, yellow, diarrhœic
stools.
_Eighth day._—30. Reports in the ears, as often as eight times a day.
Profuse sweat after the reports. Air aggravates the pain. Lancinating
pain in the region of the liver, worse when walking or stooping.
Heaviness of the head, it inclines forwards. 35. Heaviness at the eyes
when walking. Burning pain at the anus after sitting. Twinkling of the
eyes. Burning in the eyelids. Muscæ volitantes like pins’-heads. 40. Pain
from the ear to the teeth, less but longer than previously. Lancinating
pain in the orbit of the left eye, extending to the eyebrow. Toothache
worse when taking a cold drink.
_Ninth day._—Burning at the vulva followed by violent itching. Crampy
pain at the tendo-Achillis. 45. Bright-yellow stool, which cannot be
retained as soon as one stands up. Repeated sneezing. Coryza. Crampy pain
from the calf to the heel. Heaviness in the legs and weariness towards
evening.
_Twelfth day._—50. Acute pain in the knee-joint. The tongue feels big,
as if it filled the whole mouth, though the swelling is but trifling.
Red tongue. Difficulty of moving the tongue and talking. Inflammation of
the tonsils. 55. Pain in the throat and sensation as of a lump in the
pharynx. Pain in the left breast worse when walking. Itching at the left
breast and nipple, especially in the morning. Pain at the posterior iliac
spine when stretching the leg or rising, several days in succession.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: 1. Vertigo as if one would fall to the right. Stupefying
pain in the head. Aching pain in forehead and eyes. Beating in the
right temple. 5. Twinkling of the eyes. Burning in the eyelids. Muscæ
volitantes. Lancing pain in left orbit. Earache in damp weather. 10.
Sudden report in the ear, with pain extending to the teeth. Coryza.
Toothache worse after a cold drink.
GASTRIC, &c.: Hiccough. Nausea. 15. The tongue feels big as if filling
the mouth. Difficulty of moving the tongue. Red tongue. Inflamed tonsils.
Sore throat with sensation of a lump. 20. Lancing pain in the region of
the liver worse when stooping. Involuntary stools. Diarrhœa, yellow.
Burning pain at the anus after sitting. Burning at the vulva.
CHEST, &c.: 25. Itching at the left breast and nipple. Pain in left
breast. Stiffness of the nape of the neck. Pain like wry neck. Pain from
nape of neck to forehead, causing a numbness and heaviness. 30. Pain at
the posterior iliac spine when stretching the leg. Heaviness in the legs.
Acute pain in the knee-joint. Cramps at left-tarsal joint. Numbness of
the legs and tarsal joints. 35. Numbness at the tarsal joint. Crampy pain
at tendo-Achillis. Moist tetter with itching at right clavicle. Itching
red pimples on the right arm. Pimples on left side of neck. 40. Sense of
chilliness in hypogastrium.
TRADESCANTIA DIURETICA. (MART.)
TRAD. TRADESCANTIA COMMELINA (WELL.) PORTUG.: TRAPŒRAVA.
This herbaceous plant is pretty common in Brazil. Its ramose and
cylindrical stems are erect or a little inclined; the leaves are
alternate, sheathed, somewhat lanceolate, and constituting at the
extremity of the branches tufts whence arise long pedicles each of which
carries from four to six flowers; perianth double, three-leaved, the
outer one having sharp, herbaceous divisions, and the inner one being
petaloïd and blue-colored. Stamens six fertile; a free tri-locular ovary,
surmounted by a simple style. We employ the leaves.
_First day._—1. Vertigo. Pain in the left side of the chest. The
breathing is embarrassed as when one is affected with catarrh.
_Second day._—Yellowish, copious urine, depositing at the bottom of the
vessel an ash-colored, copious sediment. 5. The urine has an acrid smell.
Inflammation of the scrotum which is painful and very red. Difficult
breathing, sighing as from want of air. The symptoms continue from the
third to the fifteenth day. The breathing is very painful. 10. The
inflammation of the scrotum decreases since the twelfth day. Whitish
discharge from the urethra. Pain when urinating. Thin stream of urine.
Diarrhœa. The testicles return by the inguinal ring.
MURURE LEITE.
MUR. L.
This rosin is used as an anti-syphilitic.
1. Blennhorrhœal discharge. Ulcers on the legs. Yellow and fetid
urine. Cracking sensation in the tibia. 5. Profuse flow of saliva.
Small painless pimple which terminates in suppuration, with smarting.
Spot at the instep, painful in the middle and insensible all round the
circumference. Numbness of the left arm. Numbness of the limbs. 10.
Sciatica. Swelling of the face as in the elephantiasis of the Greeks.
Pain in a former cicatrix on the left side of the tongue. Cold hands.
Heaviness of the head. 15. Pains in the head, recurring on the third and
fourth day. Pain in the left ear, on the first day. Stool easier. Heat
in the eyes. Sore eyes. 20. Drowsy day and night. Constant restlessness
during sleep. Exaltation of ideas. Loathing of food, loss of appetite.
Pain at the left shoulder, hindering breathing when walking. 25. Pustules
on the penis. Eruption on the legs. Toothache for four days. Pimples on
the occiput, on the fourteenth day. Vomiting, on the sixteenth day. 30.
Urging to stool, with soft fæces. Little appetite. Severe pain in the
thighs. Prickings in the tongue. Heaviness of the head.
HAHNEMANN’S ARRANGEMENT.
1. Pain in the head. Heaviness of the head. Pain in left ear. Swelling
of the face. 5. Heat in the eyes. Sore eyes. Toothache for four days.
Prickings in the tongue. Flow of saliva. 10. Pain of a former cicatrix
at the tongue. Loathing of food. Vomiting. Blennorrhœa. Yellow and fetid
urine. 15. Pain at left shoulder, hindering breathing when walking.
Numbness of left arm. Cold hands. Severe pain in the thighs. Cracking
in the tibia. 20. Painful spot at the instep, insensible all round.
Sciatica. Drowsy. Restless sleep. Pustules on the penis. 25. Pimples on
the occiput. Numbness of the limbs.
CANNABIS INDICA.
CANN. IND. HASCHICH. PANGO.
This is an intoxicating, herbaceous plant, with an erect stem which is
furrowed its whole length. Leaves alternate, palmate, composed of five
almost linear, serrate folioles on slender petioles. Flowers dioïchous,
with a monophyllous greenish perianth, in groups of two, placed at the
base of the leaves, and constituting a terminal spike. The male flowers
with five reflexed divisions, five stamens with almost vesicular, pendant
anthers; female flowers with an entire perianth that is split only on one
side. Fruit ovoïd, with one seed. The haschich which has been introduced
into Brazil by the blacks, is called by them pango; they are severely
forbidden to grow it in Brazil. It can only be procured with difficulty.
We employ the leaves.
This narcotic develops a good many symptoms in those who make use of it.
It is our belief that, if it had been sufficiently proved, it would be
used as much as opium and belladonna. The few symptoms which we give
below, are simply intended to stimulate others to continue the proving of
this interesting agent.
1. Dizziness when stooping, vertigo, the head inclines backwards.
Aching in occiput and temples. Beating headache at vertex. 5. Slight
pain at the pit of the stomach. This pain is followed by a very marked
pricking sensation. These pains cease after eating. Little appetite. 10.
Contraction of the eyelids. Twinkling of the eyes. Pale face. Haggard
looks. Languid eyes, heaviness of the head. Loss of appetite. 15. Very
hungry. Bitter mouth. Tongue coated white. Urine thick and reddish.
Very drowsy, even in the day-time. 20. Weary pain in the bend of the
right elbow. Vivid, sometimes extatic dreams. Chill and heat all over.
Shuddering. Pain in the joints.
PETIVERIA TETRANDRA. (GOM.)
PET. MAPPA GRAVEOLENS (WELL.) PIPI. ERVA DE PIPI.
This bush is common in the fields around Rio-Janeiro, where it blossoms
the whole year. Its branches are erect, somewhat sarmentose, slightly
pubescent at their extremities, with alternate, glabrous, somewhat
undulate leaves. Flowers small, scattered over long axillary or terminal
spikes; perianth persistent, herbaceous, with four linear divisions.
Stamens four, alternate with the divisions of the perianth and a little
taller. A single ovary, surmounted by a style, divided into ten reflexed
stigmata. Capsule flattened, containing a single seed. The roots are
branching and very fibrous; they smell strongly of garlic.
We employ the recent root.
Prover: _Dr. Manuel Duarte Moreira._
1. Merry, disposed to sing. Deep sleep, longer than usual, for the first
three days. Drowsy all day, with frequent yawning, but no desire to
lie down. Insignificant or unpleasant dreams, scarcely recollected on
waking. 5. Sleeps longer, the first day. Headache, on waking. Sleepy with
yawning, after breakfast, the first day. Drowsy after dinner, but no
sleep, second day. Shuddering all over, sweat; the hair stands on end,
second day, 9 in the morning. 10. Heaviness of the head on waking, eight
hours after taking the drug. Weight at the vertex, which seems to press
on the brain, with heaviness of the eyelids and difficulty of opening
them, without sleep. Deep-seated and dull pain in the upper part of the
brain, worse when touched, talking or sitting; less when walking or
moving about, first day. Same symptom on the second day, but less. Sense
of fullness in the head, second day. 15. Sense of fullness in the head,
as if it would split, especially after twelve o’clock, on the third day.
Sensation as if hot water were thrown on the hairy scalp, penetrating
to the brain, second day. The headache disappears on the third day,
it becomes lighter and changes. Sight feebler and dimmer than usual.
Painful heat at the margin of the eyelids, worse when closing the eyes.
20. Dim sight after dinner, second day. Fetid breath. Sensation in the
throat as if one had swallowed some astringent substance. Sensation in
the mouth and throat as if one had eaten some acrid and resinous fruit,
second day, in the morning. Dull pain in the bowels and hypogastrium,
second day. 25. Constipation for three days. Copious urination, in the
morning. Light-colored, watery urine, without smell or sediment, third
day. Violent lancinations cinder the right breast, at each inspiration.
Slight pain at the sternum, when stooping. 30. The voice becomes hoarse
from much coughing. Weariness and numbness of the left arm, with pain in
the humero-cubital articulation, first day. Numbness of the tips of the
fingers, especially the ring-finger. Sensation at the middle of the right
thigh as if bitten by an ant; itching and heat after scratching. Cramp
in the calves during the night, second day.
Second prover: _Mlle. Norma_, 21 years old, sanguine temperament, good
constitution, pale face, melancholy disposition, chestnut-colored hair.
35. Disposed to laugh and jest, first day. Sad, desires to weep; shortly
after, involuntary weeping, sixth day, morning. Long, deep sleep, the
first three days. Sleeps all day, with frequent gaping, but no desire to
lie down. Dreams about quarrelling, she does not recollect her dreams
on waking. 40. First day, sleeps longer than usual in the morning.
Headache on waking. Somnolence after breakfast, with gaping, first day.
Drowsy after dinner, second day. Sad dreams about sick persons in her
family, fifth day. 45. Profuse, cold sweat, and chilliness all over,
with shuddering after the first sleep, sixth day. Shuddering throughout
her body, when lying down. Febrile heat, pale face, cold hands, on the
evening of the sixth day. Two small dark-yellow spots on the neck.
Headache, with a small and feeble pulse; heat in the face, especially
on the right cheek, which is felt very intensely, though the skin feels
cool, first day. 50. Painful stitch in the forehead, worse when opening
the eyes, with external heat of the head on the first day, at 2 in the
afternoon. Stabbing sensation in the right temple, first day, at 3 in the
afternoon. Dull pain, with beating in the left temple, third day. Aching
pain in the temples. Pain in the forehead, with compressive sensation
in the brain, aggravated by walking. 55. Eyes half closed, swollen
externally, surrounded by blue margins, especially near the nose, for
three days. Weight on the eyelids constraining her to close her eyes; in
this state she sees a variety of figures, sixth day. The veins of the
nose are swollen and bluish. Redness and heat of the left ear, for some
minutes, third day. Stomach-ache with sensation of coldness internally.
60. Acute and seated pain in the whole stomach, when rising from a chair,
suffocation, with cold feet, which obliges her to remain in bed, on the
evening of the sixth day. Pains in the muscles of the superior and inner
side of the elbow, like stings of ants. Contusive pain in the arms and
legs. Heaviness and weariness of the limbs, sixth day, morning. 65.
Numbness of the lower limbs, with aversion to exercise. Contusive pain in
the arms and legs, sixth day. Cold feet, in bed, morning.
Third prover: _Mlle. Silvia_, 20 years old, sanguine temperament, good
constitution, gay disposition.
Disposed to sing. Regular and deep sleep, longer than usual, the first
three days. 70. Sleeps all day, with frequent yawning, but no desire
to lie down. Unpleasant dream which she does not recollect on waking.
Wakes at 4 in the morning, falls asleep again a quarter of an hour
afterwards. Light and disturbed sleep, after breakfast, first day, 9 in
the morning. Deep sleep at 10, same day. Deep sleep, second day. 75.
General prostration, with disposition to lie down, but no sleep, third
day, 9 in the morning. Sad dreams, which she does not recollect. No
sleep in bed. Profuse and cold sweat, after her first sleep. Prickings
at the right shoulder, followed by inflammatory redness for 15 minutes.
80. Lancinations or shootings through the whole body, as if needles were
stuck in; followed by itching from the elbow to the hands, with small
violet-colored spots on the arm, back and feet, second day. Pain at
the outer part of the left arm, with a large, red, inflamed spot like
erysipelas. Heat on the surface of the body as from exposure to the sun,
the feet being cold. Pain at the vertex, as from a blow, dull pain on
the top of the head, left side, worse when turning the head or walking,
second day, 11 o’clock in the morning. Benumbing and deep-seated pain
with pressure, in the temples, and dull pain on the vertex, second day.
85. At the moment if lying down in bed, explosion in the head, the noise
passing through the ears, third day. Deep-seated pain, at times in the
forehead, at times in the nape of the neck. Aversion to exercise, she
wants to remain quiet. Laming numbness of the arm and legs, fifth day,
morning. Heaviness in the forehead, when stooping, here and there, sixth
day, noon. 90. Weight in the eyes, and prostration as from sleepiness,
without however being sleepy. Sensitiveness to the light of day. Redness
of the conjunctiva, especially near the internal angle of the left eye.
Sudden inflammation of the left eye at dinner, continuing for three
days. The flame of the candle looks yellow, and seems surrounded by a
red halo. 95. Redness of the wing of the nose and left cheek, third day.
Frequent sneezing after 12, fifth day. Redness on the left cheek. Sharp
lancinations in the epigastrium from within outwards, fifth day, evening.
Lancination in the stomach after dinner, seventh day. 100. Pain in the
throat, with difficulty of swallowing saliva. Catarrh from the third to
the fifth day. When lying down, sensation in the spine as if she had
strained it by lifting a heavy weight, first and second day, evening; the
pain is aggravated by raising herself again or by inclining backwards,
and disappears when she inclines forwards. Numbness at the wrist, along
the course of the cubital nerve, with sensitiveness to contact, second
day, evening. Shooting throughout the body, followed by itching at the
back part of the forearm, second day, morning. 105. Redness and intense
inflammation at the outer part of the left forearm, second day, 11 in
the morning. Burning pain at the left radius, with contusive sensation
when touched, third day. Violent itching of the ball of the left thumb,
followed by inflammatory swelling, third day, evening. Weariness of the
arms and legs, and numbness as after a long walk, fourth day, morning.
Painful numbness at the outer parts of the arms and legs. 110. Cold
feeling in the interior of the bones, fourth day, noon. Numbness of the
anus and legs, with deep-seated pain at times in the forehead, at others
in the nape of the neck, with aversion to motion, fifth day, morning.
Excessive coldness penetrating to the bones, hands and feet, seventh
day. Sudden numbness of the knees, with dull pain in the tibia, first
day, noon. Acute and lancinating pain in the metatarsal bone, which
corresponds to the left little toe. 115. Painful pricking in the left
fifth toe, eighth day, morning, a few moments after, the same toe feels
as if it would turn round from above downwards.
Fourth prover: _Miss Célia_, 17 years old, sanguine temperament, good
constitution, pale face, cheerful disposition, auburn hair.
Evanescent and confused ideas. Want of memory. Passing recollection,
which escape from her mind without her thinking of it. Sadness unto
tears, with headache, second day. 120. Deep sleep, commencing early, and
lasting longer than usual, for three days. Drowsy all day, with frequent
yawning, but no desire to lie down. Unpleasant dreams which she does
not recollect on waking. Quiet sleep in spite of the disturbing dreams
which she forgets on waking, second day. Prostration as from sleepiness,
without desiring to sleep. 125. Dreams about dead bodies, she wakes with
a start and cold sweat all over her body. Sensation as if the finger
were pressed on the right temple, with sensitiveness to contact, second
day, noon. Lancinating pain in the right temple, suddenly shifting to
the left temple and thence to the vertex, where a burning sensation is
experienced, second day. Pain and heat in the forehead, with pressure
on the eyes, second day, three in the afternoon. Dull pain at the root
of the nose, evening. 130. Numbness and compressive sensation as if a
warm bandage were wrapped round the head. General prostration as from
sleepiness. The voice seems to come from afar. The body seems insensible
when she is lying down, and she feels as if in a swoon. When walking she
feels as if she did not touch the soil, and as though she would fall.
135. Painfulness of the eyes, as if the eyeballs were driven out of the
orbits by some foreign body. Sensation as if the head were full of warm
water. Sadness, tears; in her sadness she remains seated, motionless,
speechless (all these symptoms occurred within an hour, second day, after
12). Headache, with weight on the eyes, second day. Sensation as if
stung by ants under the left lower eyelid. 140. Nose slightly inflamed
and shining. Dull pain at the root of the nose, on the evening of the
first day. Pain at the left wing of the nose, which spreads to the
opposite side, followed by bloating on the dorsum of the nose, second
day, at noon. Sense of heat in the face, though the skin feels cool.
Sensation as if a needle had been stuck in the upper lip from within
outwards, eleventh day, on rising in the morning. 145. Toothache. Dry
mouth. Burning tongue as from hot water, on rising from bed. On going to
bed, flow of watery and cold saliva, depositing an ash-colored sediment
and whitish granulations, which taste and smell like bile, but are not
bitter. Sharp and lancinating pain striking through the spleen from below
upwards, second day. 150. Slight colic in the descending colon. From
11 in the morning until evening she urinates every five minutes, with
heat in the urethra, second day. She urinates three or four times an
hour, without pain, third day. Urine colorless, on the following days.
Tightness and beating in the region of the heart, fourth day, evening.
155. Deep-seated and dull pains in the chest, under the sternum. Dull
pain in the posterior cervical region, when moving, the neck, second
day, noon. In the right wrist-joint she feels an internal, sharp pain
which seems to be more violent externally. A similar pain is felt at the
left wrist, but less intense. Pain from the humero-cubital articulation
to the wrist. 160. Numbness at the posterior and internal part of the
forearm. Sharp pain, and sensation of painful roughness at the forearm,
first day, evening. Pain in the right hand, from the circumference to
the centre. Sudden pain at the left little finger, striking through
the whole forearm, becoming seated at the humero-cubital articulation
and increasing gradually, with sensation of constriction, second day,
morning. Shooting, and itching at the internal and upper part of the
forearm, second day, morning. 165. Pains in the last fingers of the
right hand as if they had been struck with a hammer, second day, noon.
Sweat in the palm of the hands, second day, evening. Twisting sensation
in the scapulo-humeral articulation, when stooping, third day. Sense of
paralysis in the forearms and the phalangeal articulations, the fingers
feeling numb, third day, evening. Heat in the skin of the arm, as if
slightly burnt, after rubbing the hand over it. 170. Slight crampy
pain in the tendons of the palms of the hands, and in the forepart
of the wrist. Similar pain in the tendons of the ring-fingers, sixth
day. Renewed crampy pain in the hands, ninth day. Cramp in the right
ring-finger, tenth day. Slight cramps in the hands, twelfth day. 175.
Numbness from the knee to the sole of the foot, where it becomes seated,
first day, noon. Weakness and numbness of the legs, especially when
rising, first day, after 12 in the day-time. Weakness in the legs and
knees when stooping. Weakness in the legs, so that the knees give way,
second day, after 12. Pain at the forepart of the tibia, as from a blow.
180. Contusive pain at the calf, aggravated by contact. Dullness of the
sentient faculty when lying, as if the body were numb.
Fifth prover: _Miss Nina_, 14 years old, sanguine temperament, cheerful
disposition, red face, auburn hair.
The least cause excites her mirth; she would like to sing. Regular sleep,
generally longer than the three first days. Drowsy all day, with frequent
yawning, without any desire to go to bed. Dreams which she is unable to
recollect. Lachrymation, with sensation as of sand in the eyes. Urine
more profuse and of a lighter color. Numbness of the right arm.
Sixth prover: _Mr. Cyprien Huet_, 51 years old, sanguine temperament,
robust constitution, serious disposition, red conjunctiva, weak sight,
redness of the margin of the eyelids.
Very gay. He laughs and sings all day. Deep sleep, commencing sooner and
ending later than usual, for four days. Quarrelsome dreams, second day.
Violet-colored spots elongated horizontally, on the right hypochondrium.
Dull pain at a point on the hairy scalp, and pressure at the occiput
on the right side. 195. Boring pain at the top of the forehead, second
day. Contusive pain at the zygomata. Violent lancinations in the upper
part of the forehead and in the left side of the head, for one minute,
second day, noon. Pain in the upper part of the left parietal bone, as
if the skull would split. Boring pains in the right upper lid, first
day. 200. Dull pain at the right eye, as from a blow, relieved by
pressure, second day, noon. Slight pain in the nose. Intense and sudden
itching on the dorsum of the nose. Stoppage of the right ear, with hard
hearing. Contusive pains in the outer parts of the orbits. 205. Sensation
as of a pustule on the cheek, of the size of a pea, for some seconds.
Violent itching at the same place. Sensation in the throat as from
swallowing some astringent substance. Borborygmi when lying down, second
day, morning. Lancination in the hypochondria. 210. Mucous diarrhœa,
dark-colored, mixed with fæcal matter in hard and single fragments,
third day. Light-colored and copious urine, second and third day. Dry
heat in the palms of the hands, for several days. Sense of contusion in
the muscles of the right forearm, at the inner side between the radius
and cubitus, first day, morning. Crampy pain in the muscles of the right
hand, especially at the thumb, first day, morning. 215. Dull pain and
numbness, as is experienced when pressing the brachial nerve where it
passes over the internal condyle of the humerus; aggravated by contact,
first day, noon. Violent crampy pain in the muscles of the palm of the
right hand, for five minutes. Crampy pain in the left little finger.
Numbness of the fingers of the right hand for several hours, first day,
after 12. Lancination and heat at the tip of the right thumb, as if
there were a whitlow, extending to the first phalangeal articulation.
220. Heaviness and numbness of the extremities, first day, evening.
Contusive pain at the forearm. Itching at the last fingers. Numbness
of the extremities after rising from bed, second day, three different
times. Itching in the palm of the left hand. 225. Pain in the external
middle part of the right forearm, as if needles were thrust in. A similar
feeling at the left arm, but less distinct. On rising from bed, in the
morning, numbness and itching at the right foot, first day. Dull pain in
the knee-joint and bend of the knee, especially the first day. Numbness
and slight itching of the right leg, down to the foot, second day, noon.
230. Slight, acute and circumscribed pains in the groins, repeatedly
and at intervals. Heat in the loins, second day. Dry heat all over,
especially in the palms of the hands. General weakness, every morning
after rising from bed.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL, MORAL, HEAD: 1. Sad. Sad, motionless, speechless. Confused ideas.
Merry, disposed to sing. 5. Boring pain at the top of the forehead.
Lancinations in forehead and left side of the hand. Splitting pain in
left parietal bone. Pain and head in forehead, with pressure on the eyes.
Numbness and compressive sensation at the head as from a warm bandage.
10. Sensation as if the finger were pressed on the right temple. Lancing
pain in the temples, shifting to the vertex where she feels a burning.
Pain at vertex, as from a blow. Numb pain, with pressure, in the temples.
Heaviness in the forehead when stooping. 15. Headache, with small pulse
and hot face. Painful stitch in forehead, worse when opening the eyes.
Stabbing sensation in right temple. Dull, beating pain in left temple.
Compressive pain in forepart of head. 20. Headache on waking. Heaviness
of the head, also at the vertex. Sense of fullness in the head, as if
it would split. Sense as if hot water were thrown on the hairy scalp.
Deep-seated pain in upper part of the brain, less when walking about. 25.
Dull pain at a point on the hairy scalp.
EYES, &c.: Lachrymation and feeling as of sand in the eyes. Boring pains
in right upper lid. Dull pain at the right eye as from a blow. Pain as if
the eyes were driven out. 30. Stinging under the left lower lid. Redness
of the conjunctiva. The flame of the candle looks yellow. Eyes half
closed, bloated. Weight at the eyelids, she has to close them and then
sees figures. 35. Dimness of sight. Painful burning at the margin of the
eyelids. Toothache. Sense of heat in the face. Itching of the dorsum of
the nose. 40. Nose inflamed, shining. Pain at the alæ nasi, followed by
bloating of the dorsum of the nose. Stoppage of the right ear. Report in
the ears when lying down. The left ear is hot and red.
MOUTH, STOMACH, &c.: 45. Stitching in the upper lip. Dry mouth. Burning
in the tongue. Flow of saliva in the evening, with ash-colored sediment
and granulations tasting like bile. Sore throat with difficulty of
swallowing saliva. 50. Astringent sensation in the throat. Lancinations
in the epigastrium and stomach. Stomach-ache, with cold feeling
internally. Acute pain in stomach when rising from a chair. Circumscribed
pains in the groins. 55. Rumbling. Lancing pain in the spleen. Dull pain
in bowels.
STOOL: Constipation. Slimy diarrhœa. 60. She urinates every five minutes,
with heat in the urethra. Light-colored urine.
BRONCHIAL: Cough with hoarseness. Suffocation, with cold feet, in bed.
Fetid breath. 65. Pain at the sternum when stooping. Deep-seated pain
under the sternum. Tightness and beating in the region of the heart.
EXTREMITIES: Heat in the loins. Twisting sensation at the shoulder-blade,
when stooping. 70. Sensation in the spine as if strained when lying
down. Prickings at right shoulder, followed by inflammatory redness.
The left arm feels weary and numb. Pain at left arm, with large, red,
inflamed spot. Burning pain at left radius. 75. Inflammatory redness at
left forearm. Sense of paralysis at the forearm and phalanges. Shootings
and itching at the inner forearm. Numbness at the inside of the forearm.
Sharp pain and rough feeling at the forearm. 80. Pain in the forearm.
Contusive sensation at right forearm. Pricking pain at the outer and
middle part of the right forearm. Numbness of the right fingers. Stinging
pains at the elbow. 85. Numbness at the wrist with sensitiveness to
contact. Internal sharp pain in right wrist. Crampy pain in the palm
of the hand. Sweaty in the palms of the hands. Pain in the fingers of
the right hand, as from a blow. 90. Pain in the right hand. Dry heat in
the palms of the hands. Crampy pain in the muscles of the right hand.
Numbness of the tips of the fingers. Itching and inflammatory swelling
of the ball of the left thumb. Cramp in the ring-finger. 95. Sudden pain
from the little finger to the extent of the forearm, with constriction
at the elbow. Darting and heat at the tip of the right thumb. Numbness
of the lower limbs. Biting sensation at right thigh, with itching and
smarting after scratching. Cramp in the calves, at night. 100. Numbness
of the legs, also with weakness. Contusive pain at the calf. Numbness and
itching of the right leg. Sudden numbness of the knees. Dull pain in the
knee joint. 105. Lancing pain in the metatarsal bone. Painful pricking in
the left fifth toe, followed by a sensation as if it would turn.
SLEEP: Drowsy, yawning. Deep sleep. Drowsy after breakfast and
dinner. 110. Light sleep. Sad dreams about sick persons. Dreams about
quarrelling. Unpleasant dreams. Sad dreams. 115. Dreams about dead
bodies, she wakes with a start and covered with cold sweat. Quarrelsome
dreams.
FEVER: Febrile heat, pale face, cold hands. Heat all over. Dry heat all
over. 120. Shuddering all over. Cold feeling in the bones. Profuse cold
sweat and chilliness, first part of the night.
CUTANEOUS: Violet-colored spots on the right hypochondrium. Two yellow
spots on the neck.
GENERAL: 125. Heaviness and numbness of the extremities. Weakness every
morning. The body feels insensible when lying down, as if in a swoon.
Prostration. Dartings through the whole body, followed, by itching and
violet-colored spots on the arm, back and feet. 130. Numbness of the arms
and legs. Contusive pain in the arms and legs. Heaviness of the limbs.
JANIPHA MANIHOT. (KUNTH.)
JAN. JATROPHA MANIHOT. (LIN.) MANIHOT UTILISSIMA. (POHL.) MANIOCA MANDI.
The manioca which is cultivated, a good deal in South-America, for its
nutritious root, is a bush with a round and ramose stem, often growing
to the size of three feet high. Its leaves, which are of a sea-green
color, and supported by long petioles, are alternate, palmate, with
five to seven lanciolate, smooth and entire lobes. The flowers, which
are monoïchous, form branching panicles either terminal or axillary;
their perianth is calicoïd, campanulate, with five deep divisions of
a light-yellow color, changing to a brown at the extremity of the
divisions. Flowers male, ten stamens, with alternately long and short
filaments inserted in a fleshy disk, which, in the female flowers,
surrounds the base of a sub-globular ovary, with three uni-ovulate
chambers; no style, but three stygmata presenting six or seven thick,
compressed lobes that constitute a thick and sinuous mass. The roots,
which are tuberculous and very big, contain an abundance of milky juice
which is very poisonous when fresh, and which is extracted first by
pressure and afterwards by the desiccation of the feculent portion that
constitutes the chief nutriment of the Brazilian farmer. It is this juice
that we employ in medicine.
On the second of July, 1845, a large quantity of this dangerous liquid
was expressed before the institute, and an ounce of it was taken by Dr.
Jo. Vincente Martins, and several pupils among whom Messrs. Antonio de
Souza, Dias and Chedifer, seemed to be the most eager. The symptoms were
so violent that most of the provers were obliged to antidote them. We
trust that the devotedness of the Brazilian physicians will excite a
corresponding enthusiasm among their brethren in other parts.
_First day._—1. Eructations, at half past 6 in the morning. Slight
feeling of dryness in the œsophagus. Slight weight in the stomach. Drowsy
in the day-time. 5. Thirst. Falls asleep late. Stool easier than common.
Pain at the velum palati. Pain in the orbits. 10. Pain in the chest.
Weakness of the knees in going up-stairs. Sad. Feeble. Dizzy. 15. Acute
pain in the left arm, at night.
_Second day._—Vague pain in the abdomen, while urinating, at 6 in
the morning. Copious light-colored, watery, fetid stools. Renewed
ineffectual urging to stool, at 8. Appetite when commencing breakfast,
it suddenly ceases after taking a little milk. 20. Sense of swelling in
the left tonsil. Profuse sweat during sleep, ceasing on waking. Watery,
greenish, fetid stools. Slight dull pains in the stomach and bowels, with
rumbling. Sudden pain, with lancination in the urethra, above the fossa
navicularis, for two minutes. 25. Tenesmus and pressure in the sphincter
ani, with pricking, at 3 in the afternoon. Weight in the head, especially
high up in the forehead, at 4 in the afternoon. Drowsy, at 4 in the
afternoon. Distressing dreams, he wants to save a child from asphyxia,
but the parents refuse to have it treated. Dizzy. 30. Wakes in bad humor.
Trembling of the knees and limbs, with violent emotion when hearing other
persons talk about the malady which he fears he is afflicted with. Pain
in the side of the chest and in the shoulders, worse during motion.
_Third day._—Uncertain and transitory, but very acute pains in the
stomach. Fetid sweat in the axillæ and about the scrotum. 35. Doughy
mouth, with bad breath. Noise in the ears like that of rushing steam.
Slight heat in the urethra. Swelling of the ankles, rather less at
night. Pain in the back. 40. Pain at the left elbow. Moral and physical
prostration.
_Fourth day._—Heaviness in the stomach, all night, eased by placing the
hands upon the part. Optical illusions. Bitter mouth. 45. Pain in the
forehead and the nasal fossæ.
_Fifth day._—Pain at the inside of the thigh. Dreams about a fire with
little flames like those which were observed during the examination at
the institute of Rio Janeiro from the tenth attenuation of the crotalus
cascavella, by means of the solar microscope.
_Sixth day._—Drowsy. Diarrhœa in the morning. 50. Pain at the loins. Icy
coldness of the knees.
_Seventh day._—Icy coldness under the shoulder-blades, in bed, even when
well covered. Cold feet and hands.
_Eighth day._—Rheumatic pain in the right thigh. 55. Icy coldness in the
arm, even to the marrow. The whole head, especially the nape of the neck,
is cold.
ARRANGEMENT ACCORDING TO HAHNEMANN.
Dizzy. Sad. Bad humor on waking. The whole head and especially the nape
of the neck, are cold. Weight in the head. Pain in forehead and nasal
fossa. Optical illusion. Pain in the orbits. Whizzing in the ears.
Eructations. Thirst. Appetite at breakfast, ceasing suddenly after
tasting milk. Doughy mouth. Dry feeling in the œsophagus. Pain at velum
palati. Sense of swelling in left tonsil. Dull pain in stomach and
bowels. Weight at the stomach. Tenesmus, and pressure in sphincter ani,
with pricking. Watery, fetid stool. Ineffectual urging to stool. Painful
darting in the urethra. Heat in the urethra. Vague pain in the abdomen
when urinating. Pain in the side of the chest, during motion. Pain in the
chest. Fetid sweat in the axillæ. Acute pain in the left arm. Pain at the
left elbow. Icy coldness in the arm. Cold feet and hands. Rheumatic pain
in the right thigh. Trembling of the knees and limbs. Swelling about the
ankles. Weakness of the knees: Icy coldness under the shoulder-blades, in
bed. Distressing dreams. Drowsy. Dream about little flames. Sweat during
sleep. Prostration.
MELASTOMA ACKERMANI.
MELAST. TAPIXIRICA.
This species has never yet been described by authors. It is a bush with
round branches, triangular at their extremities, and covered with a
brownish bark. The leaves are opposite, supported by short and hairy
petioles; their limb is oval, reticulate, covered with stiff hairs, and
traversed on its lower surface by five thick almost parallel nerves
running from the base to the summit of the leaf. The flowers are sessile
supported by terminal axes. We employ the leaves.
_First day._—1. In the morning, pain in the region of the sternum.
Sneezing. Heat all over. Palpitation of the heart. 5. Buzzing in the left
ear. Acid stomach. Profuse saliva. Shuddering, then sweat. Vertigo.
_Second day._—10. Looseness of the teeth. Lancination and prickings at
the vertex. Stitches at the feet, ankles and wrists. (Disappearance
of an inveterate diarrhœa with colic). Itching and heat at night.
Tenesmus with constriction of the sphincter. 15. Pain at the perinæum.
Light-colored and foaming urine. Hardness of the penis, even when there
is no erection. Fetid urine. Digging in the teeth. 20. Heat and pricking
at the anus. Pricking in the urethra. Weakness of the thighs. Profuse
urine. Lancinations in the perinæum, the urethra and the testicles.
25. Rumbling. Urine more cloudy and less foaming. Pain in the abdomen.
Prostration. Pale face. 30. Drowsy in the day-time. Urine with white
sediment. Albuminous urine. Horrid pain and pulling from the perinæum
to the groin, for six hours; while seated and not passing off in any
position. Violent shuddering for four hours, followed by heat without
sweat. 35. White coated tongue. Bitter mouth. Pain in the loins. Red
urine without smell, with bloody coagula. Headache and sensitiveness of
the hairy scalp. 40. Œdema of the legs. Eruption on the lips, especially
the upper. Internal heat.
SEDINHA.
Herbaceous plant, with a slender, round and pubescent stem; the leaves
are opposite, lanceolate and very sharp; their upper surface is hairy
and of a darker green than their lower surface, which is covered with
long, silky hairs. This plant is quite common in the neighborhood of
Rio-Janeiro. We employ the leaves.
1. Aching pain at the sternal articulation of the fourth ribs. Internal
itching, with desire to scratch, in the pit of the stomach. Sensation
in the region of the liver as if penknives were thrust in. Tenesmus.
5. The urine burns like boiling water. Restless dreams about murders,
monstrous animals. Distress on seeing any one eat. Pain in the pit of
the stomach in raising one’s-self. Pressure in the temples and vertex.
10. Bone-pains above the eyes. Constant yawning for two days. Pain in
the abdomen, after dinner, apparently proceeding from the pit of the
stomach, with slight colic. The teeth are sensitive and set on edge,
especially the right upper incisores. Itching in the left ear, with a
good deal of ear-wax. 15. Digging pain in the right lung. He raises a
bloody mucus. Desquamation on the back of the hand, extending to the
nails, where the skin becomes loose and forms hang-nails. Itching at the
pubis. Pimples and itching on the back, chest and arms. 20. Colic in the
evening, with incarcerated flatulence; relief is obtained by the emission
of flatulence. Toothache after eating, with bleeding and sensitiveness
of the gums. Pain in the bad teeth. Headache as if from water-bubbles
enclosed here and there in the forehead. Sense of excoriation in the
urethra. 25. Slight pain in urinating. Discharge from the urethra of a
water mixed with little mucous flocks. Heat on the back of the hand as
if scorched by the sun, followed by desquamation. The gums are extremely
sensitive, and the incisor teeth set on edge. Ludicrous dreams; he is
pursued by crocodiles and he drives them away by sneezing. 30. Coffee
aggravates the symptoms; the incisor teeth are set on edge, with sense of
coldness in these teeth which descends from time to time. Caries of an
incisor tooth.
SPIGGURUS MARTINI. (NOBIS.)
SPIG. SPIGGURUS SPINOSA (FR. CUV.) HISTRIX SUBSPINOSUS. THE PORCUPINE.
This little animal is common in Brazil where it lives on trees and
secures itself by means of its hind-feet, it uses its tail, which is
pretty long, as a means of descending. Its length, from the muzzle to
the tip of the tail, is about a foot; the tail is almost as long as
the trunk. The upper parts of the body are covered with sharp prickles
about an inch and a half long, and attached to the skin by means of a
very thin pedicle. The head-prickles are white at the base, black in the
middle and of a yellowish-brown at the top, the dorsal prickles are of
a sulphur-yellow at their base. The prickles on the rump and the first
third of the tail, are black at their extremity. All the prickles are
very close together, mingled with a few long and fine hairs. The lower
limbs are covered with a grayish fur, interspersed with little prickles;
the tail is furnished with prickles at its upper part, and is covered
with stiff and black hairs; the extremity of the tail is bare.
We triturate the prickles taken from one of the sides.
Prover: _Jo. Vincente Martins._
_First day._—Took one dose of the third trituration at 8 in the morning.
1. Desire to vomit and nausea at the sight of food, immediately. At
night, sense of dryness and fullness in the stomach. Very drowsy after
dinner.
_Second day._—5. Wakes early. Merry and quiet dreams. Sense of fullness
in the abdomen, at 5 in the morning, when lying. Diarrhœa. Transitory
pains in the toes, right temple and one of the right cuspidati. 10. Pains
at the lower extremity of the right forearm. Pain at the right zygoma.
Pain at the first incisor. Bleeding of the gums. Pain in one half of the
head. 15. Buzzing in the ears. The knees give way, likewise the tarsal
joints. The toothache becomes obstinate. After dinner all the pains
cease. Shuddering with chattering of the teeth. 20. Cough with pains in
the chest. Stitch in the region of the heart, left side, which stops
his speech for two minutes. Pain at the right arm, from the hand to the
elbow, as if extending the arm were prevented by a string. Improvement
when turning the arm or lifting a weight, or moving it about; aggravation
as soon as these movements cease. After breakfast, boring pain through
the bones of the skull. 25. Aggravation when lying down, and improvement
when walking in the open air. Pains in the stomach, as if strung together.
_Third day._—Quiet sleep with merry dreams; in the morning he dreams of
insects and a serpent which it was difficult to kill. Painful sensation
at the articulation of the jaw. Whizzing and buzzing from the left ear
to the back part of the head. 30. Long-lasting prickings at the zygoma.
Very much disposed to write, in the morning, ceasing after breakfast.
Heaviness of the head from 10 to 11. Abundant desquamation in the region
of the whiskers and at the knee. The whizzing in the ears continues. 35.
Acute pain in the intercostal muscles, in the evening, while riding on
horseback. Prickings on the vertex from time to time, especially on the
right side. Pain at the lower extremity of the forearm. Dizziness in
the back part of the head when writing. Roaring in the ears, as from a
distant gale. 40. Bitter mouth and throat, with salt taste. Nausea, with
piercing pain in the back, for 15 minutes.
_Fourth day._—Boring pain through the skull-bones. Cough as the day
before. General weakness. 45. Drowsy all day. Lancination in the left
side of the head, through the skull-bones; inability to move the head,
for three minutes. When sitting or rising, lancinating pain in the right
big toe hindering walking, for two minutes. 50. Painful swelling of the
abdomen, before dinner. Itching of the pubis after taking tea.
_Fifth day._—Disposed to yawn, with flow of saliva. Lachrymation. Stitch
in the left side, for five minutes, hindering gaping. 55. Shootings in
the epigastrium, for several minutes. Pain in the left side, at the
moment when he attempted to gape. Acute pain from the left ear to the
jaw, for two minutes. Constriction from the neck to the diaphragm, with
heaviness of the head and arms. 60. Numbness for half an hour. Pain in
the right side, for two minutes, as if a plug were thrust in. Pain in
the urethra after urinating, worse when stooping in order to pick up
something. Pain around the navel. Continued swelling and pain of the
abdomen, down to the left groin. 65. Drowsy. Good appetite. Nausea after
dinner. Shuddering from time to time. Heat and numbness of the feet. 70.
Merry dreams, at night.
_Sixth day._—Itching all over, with bleeding after scratching. Pain in
the right arm, as if the bones were broken, with inability to grasp
any thing. Deafness on the left ear, as if stopped. Inconsistent and
capricious mood.
_Tenth day._—The scales on the head and in the whiskers are less;
before, they were so thick that he did not feel either the cold or
heat, and was insensible to water. Irritable, he quarrels about the
least trifle. Cracks between the toes. Violent pain in the left kidney.
Constant whizzing in the ears. 80. The speech is sometimes embarrassed.
He discovers some gray hairs. His hair falls off. Every thing is
disagreeable to him; he desires to travel.
ARRANGEMENT ACCORDING TO HAHNEMANN.
Dizziness behind the head. Capricious mood. Every thing is disagreeable
to him, he desires to travel. Prickings on the vertex. Darting through
the left skull-bones. Hemicrania. Boring pain in the skull, after
breakfast. Heaviness of the head. The hair falls off. Lachrymation.
Deafness on the left ear. Whizzing in the ears. Buzzing in the ears.
Pain in the articulation of the jaw. Bleeding of the gums. Pain at the
right zygoma. Prickings at the zygoma. Bitter mouth, with salt taste.
Nausea, with piercing pain in the back. Desire to vomit at the sight of
food. Drowsy after dinner. Embarrassed speech. Constrictive pain in the
stomach. Dry and full feeling at stomach, at night. Painful swelling of
the abdomen, before dinner. Shootings in the epigastrium. Pain in right
side as from a plug. Pain around the navel. Violent pain in the left
kidney. Sense of fullness in the abdomen. Pain in the urethra, after
urinating, worse when stooping. Itching of the pubis, after taking tea.
Cough with pain in the chest. Stitch at the heart. Constriction from the
neck to the diaphragm. Pain in the intercostal muscles. Pain in right
arm, as if broken. Pains at lower end of the right forearm. Pain at the
right arm, as if the stretching were prevented by a string. The knees
give way. Heat and numbness of the feet. Cracks between the toes. Lancing
pain in the right big toe. Yawning. Morning-dream about a serpent.
Merry dreams. Shuddering. Shuddering, with chattering of the teeth.
Desquamation at the whiskers. Itching all over, with bleeding after
scratching. Pains in the toes, right temple. Feels better in the open air.
CONVOLVULUS DUARTINUS. (NOBIS.)
CONVUL. DUART. CALONYCTION SPECIOSUM. (D. C.) IPOMEA BONA NOX. (LINN.)
CONVOLVULUS PULCHERRIMUS. (WELL.) MORNING-GLORY.
This is a climbing plant, cultivated in America and Europe. Leaves large,
entire, cordate, alternate, on long petioles, generally arising from the
axil of the flower-bearing branches. Calix with five unequal folioles,
the three outer ones sharp, the two inner ones oval and foliaceous. Corol
white, large expanding into a large circular limb. Stamens five, adhering
by their filaments to the tube of the corol which is shorter than the
stamens. Anthers linear acuminate. The base of the ovary is surrounded
by a glandular disk; style very long, filiform, terminated by a shaggy,
bilobate stygma; fruit with a coriaceous tegument. There are two or three
flowers on the flower-bearing pedicels; they resemble a trumpet in shape,
whence their Brazilian name “herva trombetta.” This plant blossoms in the
summer-months. We employ the flower.
Prover: _Dr. Manoel Duarte Moreira._
1. Heat and burning of the skin all over, with prickings like the stings
of insects. Profuse sweat in bed, several nights in succession. Red spot
on the right cheek when rising from bed, it disappears in the course of
the day. Shuddering in the day-time, several different times. 5. Small
red spot in the right side of the neck. Drowsiness in the evening, in
three provers. Prostration, in two provers. Dreams about quarrels.
10. Reveries in the day-time. Dreams about dead persons and about the
incisores falling out. Dreams that one flies along an illuminated
street; appearance of a ghost; waking with a start. Languor. Sinking of
the moral strength, in two provers. 15. Hypochondria. Mental languor.
Discouragement. Pain in the left temporal region, in relation with the
eye. Pain at the right cheek. 20. Pain in the frontal region. Dizziness,
in three provers. Pain all over the head, especially along the median
line. Pain in the frontal region, with heat at the root of the nose, in
three provers. Two small spots on the forehead, disappearing in a few
minutes. 25. Pain in the whole head, from the morning until 5 o’clock
in the evening. Acute pain in the left temporal region, in the morning,
on two consecutive days, in two provers. Headache, at times at the
vertex, at others at the occiput. Pain in the temples. Violent pain at
the vertex, evening. 30. Pressure in the frontal region. Headache on the
left side. Heaviness and dizziness in the frontal region, two days in
succession. Burning in the frontal region, ceasing after taking a cold
bath. Violent pain at the vertex, morning. 35. Vertigo with fainting.
Slight pain at the vertex. Inflammation of the left eye. Dark redness of
the face. Slight heat in the upper part of the œsophagus. 40. Sore throat
for eight days. Sense of swelling at the tongue. Toothache. Swelling of
the gums. Bad taste in the mouth. 45. Spitting up of mucus. Heat and
dryness at the anterior and superior part of the œsophagus, in three
provers. Slight pain on each side of the thyroid cartilage. Appetite
when rising in the morning, in two provers. Stomach-ache for three days.
50. Decrease of the appetite. Pain in the abdomen, with internal heat.
Violent colic with pulling, in two provers. Constipation, the first days,
in eight provers. Red urine. 55. Yellow sediment in the urine. Numbness
of the left scapular region. Pain at the left shoulder. Numbness of the
arm, worse when hanging down. Numbness of both arms. 60. Deep-seated pain
in the left forearm. Numbness of the right index- and middle-finger. Pain
in the left wrist-joint. Deep-seated pain under the right breast. Pain at
the right knee. 65. Deep-seated pain in the calves. Pain at the forepart
of the left leg, for four days. Laming pain of the legs and thighs for
several days. Deep-seated pain, first in the left, then in the right
thigh. Numbness of the left leg and heel. 70. Shooting stitch in the
right knee.
ARRANGEMENT ACCORDING TO HAHNEMANN.
MENTAL, MORAL, HEAD: 1. Vertigo with fainting. Dizziness. Pain all
over the head. Headache, at the vertex and at times at the occiput. 5.
Pressure in the frontal region. Burning in the frontal region. Pain in
the left temporal region, also acute. Pain in the frontal region, also
with heat, at the root of the nose.
EYES, &c.: Inflammation of the left eye. 10. Swelling of the gums.
MOUTH, STOMACH, &c.: Sense of swelling at the tongue. Sore throat. Heat
in upper part of the œsophagus. Bad taste in the mouth. 15. Decrease of
appetite. Stomach-ache for some days. Pain in abdomen, with internal
heat. Colic, with pulling. Constipation. 20. Red urine. Yellow sediment
in the urine. Deep-seated pain under the right breast. Pain on each side
of the thyroid cartilage. Numbness of the left scapular region.
EXTREMITIES: 25. Pain at left shoulder. Deep-seated pain in left
forearm. Numbness of the index- and middle-finger. Numbness of the arms.
Deep-seated pain in the calves. 30. Laming pain of the legs and thighs.
Deep-seated pain in the thighs. Numbness of the left leg and heel.
Shooting stitch in the right knee.
SLEEP: Quarrelsome dreams. 35. Reveries. Dreams about dead persons and
about teeth falling out. He dreams that he is flying along an illuminated
street. Burning of the skin all over, with stinging. Profuse sweat in
bed. 40. Shuddering, repeatedly. Red spot on the right cheek, when rising
from bed, also on the neck. Prostration, also moral.
BUFO SAHYTIENSIS. (NOBIS.)
BUFO. BUFO AGUA (LAT.) TOAD.
This toad is found all over America; it inhabits swamps and marshy
regions. It is as big as two fists, though its size varies a good deal.
It is readily known by its enormous rhomboïdal parotids, whence it sends
forth a large quantity of poison. Its head is flat, triangular, more
large than long; it shows a strong osseous edge, commencing at the tip of
the muzzle, thence stretching towards the inner angle of the eye, round
this organ, and finally terminating behind the lids. The eye and the
tympanic wall are very large. The trunk, which is very large anteriorly,
in consequence of the large development of the parotides, is covered,
on each side of the dorsal spine, with two irregular rows of large
elliptical or conical bladders; sometimes there are such bladders on the
sides. The anterior extremities do not reach to the end of the trunk; the
posterior extremities reach beyond the muzzle by the length of the fourth
toe. The toes are rather flattened; the first toe is longer than the
second. Its colors are various, consisting of a number of brown spots,
which coalesce on the back, and are separated on the abdomen by yellowish
dots.
The horrible croaking of these animals is well known, and might rouse the
indignation of the most phlegmatic individual.
By exciting the animal, we caused it to spirt its saliva, which we
collected on a little sugar of milk, and at once prepared, by trituration.
Prover: _Bruno Vidal._
_First day._—1. Extreme heaviness of the head, at 2. Aversion to work,
with inability, the whole afternoon.
_Second day._—Pain at the sacrum, worse when rising, stooping or sitting.
Almost continual expansive pressure in the orbits, and sensation of
internal itching; he is obliged to rub his eyes with the palm of his
hand. 5. Itching at the pubis. Itching at the face. Violent itching at
the lips.
_Third day._—Pain at the inner part of the right knee. Easy stool. 10.
Itching, almost all over. Not disposed to study. Less active than usual.
Expansive pressure and itching in the orbits. The pain at the sacrum
continues.
_Fourth day._—15. The pain at the sacrum is less; the pain at the knee
has ceased. Expansive pressure and itching in the orbits. Itching almost
all over. Constant erections without desire; not disposed to intellectual
labor, not very active.
_Fifth to tenth day._—Laziness of mind as before. 20. Constant
erections, but no desire. Itching and expansive sensation in the orbits.
_Eleventh day._—No sleep.
_Twelfth day._—Prickling at the right big toe.
_Thirteenth day._—Crampy pain at the outer side of the right leg. 25. Red
pimple, which breaks and leaves a black spot in its place. Pricking in
the pit of the stomach. Pinching at the inside of the left elbow.
_Fourteenth to fifteenth day._—Pressure at the cartilages of the false
ribs. Loathing of study.
_Seventeenth to eighteenth day._—30. The eyes are red and smart. A former
fungus bleeds. The orbits feel larger, and as if they were in contact
with the orbital walls. Aversion to work. He is apt to forget things
which he had been occupied with a moment ago.
_Nineteenth day._—35. The eyes smart and are painful when touched.
_Twentieth to Thirty-fifth day._—Careless. Lazy and discouraged. No
disposition to work. Weak memory. 40. The upper portion of the orbits
seems to be in contact with the orbital walls, especially at night. He
is obliged to rub his face in the morning. Formication of the lower jaw.
Itching at the lumbar vertebræ. Itching at the anus. 45. A black spot on
the right outer ankle, which had remained after a pimple, continues.
_Thirty-sixth day._—Large red pimple on the occiput.
_Thirty-eighth day._—Very gay in the evening. Disposed to talk about
merry things.
_Thirty-ninth day._—Gay. Lively. 50. The pimple at the nape of the neck
remains. Itching at the lumbar vertebræ. Pain in front of the lobule
of the left ear. Ganglion on the sole of the right foot. Excoriation
of the left masseter muscle, discharging a little sanguinolent humor.
55. Heaviness of the head after a walk. The eyes smart and are painful
when touched. Sleeps for an hour, in the middle of the day, contrary to
habit. Sad, he avoids company. He is unable to act with decision, he
forms projects and does not accomplish them. 60. Tingling in the lumbar
region. Dreams every night, does not recollect his dreams on waking.
Pressure on the right side of the forehead. Taciturn and gloomy. Painful
sensation under the false ribs. 65. Itching at the sacrum. (Sense of
weakness in the whole left side of the head.) Prickings in the tips of
the fingers of the right hand and the left toes. Pimples on the forehead.
Weakness of mind and memory, less in the evening. 70. Acute lancinations
in the left temple. Acute pain in the right wrist. Continual headache.
Pain in the extensor muscles of the right arm. Pimple on the right wrist.
75. Violent itching. Drowsy. Poetical and philosophical dreams. Exalted
imagination.
ARRANGEMENT ACCORDING TO HAHNEMANN.
1. Sad, he avoids company. Exalted imagination. Indolence of mind. Merry
and talkative. 5. Pressure on the right side of the forehead. Darting
in the left temple. Heaviness of the head. Expansive pressure in the
orbits, and sensation of internal itching. The eyes are red and smart.
10. The orbits feel larger, and as if in contact with the orbital walls.
Formication of the lower jaw. Violent itching at the lips. Itching of the
pubis. Erections without desire. 15. Pain under the false ribs. Tingling
in the lumbar region. Pain at the sacrum, worse when rising. Itching at
the lumbar vertebræ. Prickings in the tips of the right fingers. 20.
Acute pain in the right wrist. Pain at the right knee. Prickling at
the big toe. Poetical dreams. Red pimple, leaving a black spot after
breaking. 25. Excoriation at the left masseter muscle. Aversion to work.
Itching all over.
JACARANDA CAROBA. (D.C.)
JAC. BIGNONIA CAROBA. (WELL.)
This is a tree with white wood, the ramose top of which attains a height
of from 20 to 28 feet. Leaves pennate, tri- or quadrijugate, composed
of from five to nine opposite, sessile, glabrous and oval folioles.
Flowers large, violet-colored, on pedicles that are expanded at their
extremities, and forming ramose terminal panicles. Calix tubulous,
with five teeth, corolla tubulous, slightly pubescent externally, and
expanding at its summit into a limb with five obtuse divisions. Stamens
five, one of which is rudimentary; ovary avoïd, surmounted by a simple
style terminating in a bilamellary stygma. The husks are linear and flat.
The caroba is very common in Brazil, in gardens and on plantations; it
blossoms in September. We employ the flower.
Several varieties of the caroba are used in Brazil for the treatment of
syphilitic diseases. For our provings we have selected the Jacaranda
caroba, which has furnished results as complete as could be desired. We
consider this drug of great importance in the treatment of chancres.
_First day._—1. Stitch at the heart; the heart seems to beat slowly in
placing the hand upon it, at 9 in the evening. Stitch and pulling below
the stomach, on the right side, at midnight. Dryness and pricking all
over.
_Second day._—No sleep at night and drowsy in the day-time. 5. Dry mouth,
in the morning, in bed. One does not feel any longer the beats of the
heart, in the morning, in bed. The heart beats regularly again after
going into the open air. Painful stitch at the heart, almost constantly.
Full and slow pulse, in the morning, in bed. Weary while talking. 10.
Drawing pain on the right side, from the axilla to the false ribs, at
9 in the morning. Dull pain under the sternum, in raising the head
and drawing breath. He eats little, though his appetite is good, at 9
in the morning. General weakness, in the morning. Slight pain at the
articulation of the second phalanx of the fingers of the right hand,
at half past 9 in the morning. 15. Weakness of the legs. Pain as if
bruised in the right knee, while walking, at 10 in the morning, of short
duration. Sense as if bruised in the muscles and bones of the legs.
Slight drawing pain from the eye to the right lower jaw, followed by
shuddering in the same region, at 11 in the morning; this pain recurs,
changing to a contusive pain. Sensitiveness of the malar bone when
pressing on it with the finger. 20. Sensation of painfulness at the
apex of the heart, on the right side, at noon. Hurried breathing, with
sense of fullness under the sternum, several times in the course of
the day. Painful stitch under the false right ribs, at noon. No stool.
Momentary drawing in the flexor communis digitorum, left wrist, at half
past 12, afternoon. 25. Pulling from the lower extremity of the forearm
to the right little finger, for one hour. Weariness of the limbs, and
desire to remain seated. Weakness of the limbs; and lumbar region, at 2.
Slight pain in the right ribs, below, at half past 2. Painful fullness
in the right temple, shifting a moment after to the left temple, and
disappearing in the left side of the nape of the neck, in the evening,
in the open air. 30. Sense of fullness in the head, in the afternoon.
Dull pain between the forehead and right temple; it disappears in the
evening, by shifting to the opposite side. Pain as if excoriated at the
left side of the tongue. Pulling from the lower jaw to the middle of
the neck, on the right side, in the evening. Fullness in the pit of the
stomach, with feeble, hurried breathing; sometimes a strong and long
inspiration, with strong and sudden expiration, in the afternoon. 35.
Lancinating pain in the region of the heart. Continued prickings under
the sternum. Painful stitch on the left side of the navel. Sensation,
while walking, as of dull thorns or little pieces of straw between the
thighs, or as if stiff and dry moss is applied to a raw sore. Itching at
the anus, while sitting. 40. Pain at the left elbow, striking through
the whole forearm by fits and starts, in the evening. Dull pain in the
right wrist-joints, penetrating to the middle of the forearm; a similar
sensation at the left arm, but slighter. Pain as if bruised in the bones
of the right forearm, and lancination from the wrist to the forearm, at
6 in the evening. Acute deep-seated, drawing pain under the left last
rib, at 6 in the evening. Palpitation of the heart in going up- and
down-stairs, with acute pain, as if it were pushed with the tip of the
finger, at 9 in the evening.
_Third day._—45. Doughy mouth, at 6 in the morning. The heart seems to
beat in the pit of the stomach, at 6 in the morning; its beats are no
longer felt under the left breast. The beating of the heart recommences
during motion, but is slow and feeble. Noise in the ears, like the
flapping of the wings of a butterfly, at 8 in the morning. Sneezing
and fluent discharge from the nose, at half past 8 in the morning.
50. Itching at the left commissure of the lips, at 9 in the morning.
Fatiguing drawing pain in the anterior cervical muscles, extending to
the right ear, at half past 9 in the morning. Colic; flatulence shifts
about in the abdomen, followed by emission of inodorous flatulence, at
half past 9 in the morning. Painful stitch in the integuments of the
abdomen, between the navel and the pit of the stomach, a little on the
right side, at 10 in the morning. Dull pain above the wrist and in the
radius, at half past 10 in the morning. 55. Dull crampy pain in the right
elbow, shifting afterwards to the left elbow. Pain as if bruised in the
right side, at a quarter of 11 in the morning. Painful stitch at the
heart, shifting at once to the other side, as if one had two hearts, at
11 in the morning. Extensive aching pain from the right upper part of
the forehead to the eye, at noon. Slight pain in the right temple, as
if several dull points were pressed upon it at the same time; dull pain
in the right orbit. 60. Coryza at half past 12. Mouth dry and doughy.
Sensation in the skin as if grasped, on the right side of the navel, at
one in the evening. No stool. Lancination from the elbow to the middle
of the forearm, thence to the left wrist, from 9 to 3 in the evening.
65. Stoppage of the nose, at 3 in the evening. Boring pain at the right
external carotid, at half past 3 in the evening. Vertical pullings above
the pit of the stomach, at 4 in the evening.
_Fourth day._—Stiffness of the loins and pain in the abdomen and
hypochondria as if bruised, at 6 in the morning. Soft and easy stool,
(previous to the proving the stools were generally hard and painful.)
70. The inflammation of the anus has disappeared. Coryza, with heaviness
and weariness at the vertex, forehead and eyes, at 9 in the morning.
Coryza, with digging, lancinating pain in the left side of the forehead,
corresponding to the palatine arch of the same side, at noon. Dry lips,
mouth and tongue. Intense itching between the left ring- and little
finger, and a red, itching spot on the second phalangeal joint of the
ring-finger. 75. A red spot, with a yellowish pellicle and itching at
the forepart of the wrists, at noon. Heat at the left ear, with burning
digging pain extending to the left nostril, at half past 2 in the
evening. Sensation as if the left ear were stopped up, at half past 3 in
the afternoon.
_Fifth day._—The coryza has ceased.
_Sixth day._—80. Dreams about objects, which he defends courageously
against thieves, who lay a thousand snares for him; also about unknown
fruits, which he desires to taste, but which disappear immediately. Dull
pain at the outer side of the right eyebrow, passes off in the open air.
Acute pain in the left testicle, when walking. A good deal of appetite.
Rheumatic pain in the right knee, it disappears by motion. 85. Slight
pinching at the extremity of the prepuce. Dull pain in the right temporal
region, at 10 in the morning.
_Seventh to thirteenth day._—Slight pains in the left testicle when
walking, or by the pressure of the clothes.
_Fourteenth day._—Heat and swelling of the scrotum, near the left groin,
with pain when rubbing or touching it. Slight suppuration between the
glans and prepuce, on the right side.
_Fifteenth day._—90. The swelling of the scrotum is less, the suppuration
of the glans worse.
_Sixteenth day._—Itching at the forehead, as if mosquitoes were walking
about there.
_Eighteenth day._—The swelling of the scrotum has disappeared, the
testicle is less painful; the suppuration has spread to the outer side
of the prepuce, without affecting the glans. Swelling of the right
groin which is painful when touched. Pain as from a plug pressing
perpendicularly against the forehead, right side. 95. Violent sneezing.
Dreams about a frightful storm, with smashing and burning of palaces, or
crushing gigantic mountains, from which issue columns of smoke.
_Nineteenth day._—Profuse watery discharge from the nose. Food tastes
flat or acid, sugar-water tastes like vinegar.
_Twenty-first day._—Acute pain in the prepuce, as if a small bundle of
fibres were seized. 100. Prickling at the prepuce. Profuse discharge of
a yellowish white liquid from the prepuce, smelling like ordinary pus.
Heat and pain of the penis, the inflammation being worse in bed. The
prepuce cannot be drawn back. General malaise, nausea, debility. 105.
The swelling of the scrotum has entirely ceased. The testicle remains a
little swollen and painful. (The excrescence at the anus has considerably
decreased for eight days past.) Dreams about combats, dead persons; he
picks up very small heads, which had been partially calcined on a pan
with coals; these heads opened their eyes and spoke to him in an angry
tone.
_Twenty-second day._—The pain and inflammation of the prepuce are less.
110. The pain in the testicle keeps decreasing. Very weary in the
evening, he has to lie down. The suppuration and inflammation of the
prepuce augment in the evening, the whole prepuce is affected. Itching at
the scrotum.
_Twenty-third day._—Acute pain, with lancinations at the anus, as if
a large needle were stuck in three or four times. 115. Prostration; a
trifling exercise fatigues him and compels him to lie down. Weariness of
the knees. Sensation of a greenish-yellow pus from the prepuce.
_Twenty-fourth day._—Profuse secretion of a greenish-yellow liquid from
the prepuce. The internal membrane of the prepuce is inflamed.
_Twenty-fifth day._—120. Itching at the anus, in the morning. The
inflammation of the prepuce is less on the right side, it shifts to the
left. Itching and prickling at the margin of the prepuce. Emission of a
light colored urine, four or five times a day.
_Twenty-sixth day._—The inflammation on the inner side of the prepuce has
ceased, whereas the margin has become inflamed over night; and it is raw
and bleeds here and there. 125. The contact of the urine causes tearing
pains, which affect the whole organism, and leave a considerable malaise
behind. The nervous system, head and neck are painfully affected by
these pains. The orifice of the urethra looks like two small lips, which
are inflamed on the inner side; on touching them, a slight itching is
experienced there, extending to the middle of the penis.
_Twenty-seventh day._—130. Internal chilliness, as if the blood would
freeze in the vessels, in the open air, for fifteen minutes. Erections,
which the continual swelling of the prepuce renders painful. Total
suppression of the sexual desire, with relaxation of the penis.
_Twenty-eighth day._—Sound sleep. The inflammation and suppuration of the
glans diminish considerably in the morning.
_Twenty-ninth day._—135. He is able to take a long walk without getting
tired.
SECOND PROVING.
_First day._—Sense of constriction at the throat, until evening.
Rheumatic pain in the left shoulder-blade.
_Second day._—The pain in the shoulder-blade continues until evening.
_Third day._—Restless sleep; frightful dreams. 140. Dull pains in the
head, in the day-time.
_Fourth day._—Itching pimple at the glans, of the size of half a grain of
corn.
_Fifth day._—Restless sleep, and eccentric dreams. Painless suppuration
of the pimple on the glans; with itching; it looks like a chancre.
Heaviness of the head, which is painful all day.
_Sixth day._—145. Restless night; sleep is frequently disturbed, with
extreme difficulty to fall asleep again. The chancrous pimple on the
glans has dried up; there remains in its place a red point; the place is
not painful. The throat is very dry.
_Seventh day._—Restless at night, with uneasy and unrefreshing sleep.
_Eighth day._—Rheumatic pain in the right calf. Restless night.
_Ninth day._—150. Sleep more quiet. The pain in the calf continues; it is
intense and hinders walking.
_Tenth day._—Sore throat, with constriction of the pharynx and difficult
deglutition. The pain in the calf has shifted to the shoulder blade,
extending from the last ribs to the neck. The neck is so painful that it
is only with difficulty and pain that the head can be turned to the right
side.
_Eleventh day._—155. Similar pain in the shoulder-blade and neck. The
constriction of the throat continues.
_Twelfth day._—Same symptoms as on the eleventh, but less intense. No
sleep at night, and drowsy in the day-time. Pain in the nape of the
neck. 160. Pain under the sternum. Weariness and prostration. Emission
every night. Heat at the anus. Prickings around the anus. 165. Fever.
Prostration, so that he is scarcely able to speak. Dry cough. Cough,
with white, watery expectoration. Ulcers on the legs. 170. Pains in the
joints. Sore eyes. Pain in the right leg. Bad taste in the mouth, in the
morning. Headache, in the day-time. 175. Catarrh. Pressure at the pit of
the stomach. Nausea when eating. Pain in the back and chest. Acute pain
at the hypogastrium, when pressing upon it. 180. He wakes with a start,
twice in the night. He dreams loud all night. Pain in the left arm, in
the morning. Redness at the left arm. Painful stitch under the right
ribs, when drawing breath, for half an hour.
ARRANGEMENT ACCORDING TO HAHNEMANN.
HEAD, &c.: Dull pain in right temple, as if several points were pressed
upon it. Frontal headache. Dull pain between the forehead and right
temple, shifting to the other side and there disappearing. Sense of
fullness in the head. Painful fullness in right temple, shifting to the
left and disappearing in the nape of the neck. Pain in right side of
forehead as from a plug pressing against it. Itching at the forehead
as from vermin crawling about there. Heaviness of the head, it aches
all day. Sore eyes. Flapping in the ears as of wings. Stoppage of the
left ear. Heat at the left ear, with burning digging pain extending to
the left nostril. The malar bone is sensitive to pressure. Drawing pain
from the eye to the right lower jaw, followed by shuddering in the same
region. Sneezing and fluent coryza. Coryza, with heaviness and weariness
at the vertex, forehead and eyes. Coryza, with digging and lancing pain
in left side of forehead. He dreams about fighting with thieves. Catarrh.
GASTRIC, &c.: Food tastes flat or acid. Bad taste in the mouth, in the
morning. Nausea when eating. Dry mouth, in the morning, in bed. Raw
pain at left side of the tongue. Mouth dry and doughy. Sore throat with
constriction of the pharynx and difficult deglutition. Constrictive
sensation at the throat. Stitch and pulling below the stomach. Fullness
in pit of stomach, with hurried breathing. Pulling from above downwards
in the pit of the stomach. Pressure at the pit of the stomach. Bruising
pain in right side. Painful stitch in the integuments of the abdomen,
between the navel and the pit of the stomach. Colic with flatulence.
Acute drawing pain under the left last rib. Painful stitch on the left
side of the navel. Swelling of the right groin, painful when touched.
Sensation on right side of navel, as if the skin were seized. Acute pain
at the hypogastrium when pressing upon it. No stool. Soft and easy stool.
Itching at the anus while sitting. Heat at the anus. Prickings around the
anus. Acute pain with lancination in the anus. Excrescence at the anus.
The orifice of the urethra looks like two small inflamed lips, itching
when touched. Heat and pain of the penis. Discharge of a yellowish white
liquid from the prepuce. Prickling in the prepuce. Pain in prepuce, as if
a small bundle of fibres were seized. The prepuce cannot be drawn back.
Suppuration between the glans and prepuce. Acute pain in left testicle
when walking. Heat and swelling of the scrotum. Slight pinching at the
prepuce. Emission every night. Itching pimple at the glans, suppurating
like a chancre, and leaving a red point when dry. Suppression of the
sexual desire. Painful erections, owing to the swelling of the prepuce.
The contact of the urine causes tearing pains, which affect the whole
organism. Itching and prickling at the margin of the prepuce.
CHEST: Dry cough, with white, watery expectoration. Painful stitch under
the right ribs, when drawing breath. Drawing pain from the right axilla
to the false ribs. Dull pain under the sternum when raising the head
and drawing breath. Hurried breathing, with sense of fullness under the
sternum. Painful stitch under the false right ribs. Prickings under the
sternum. Pain at the apex of the heart. Lancing pain in the region of the
heart. Palpitation in going up- or down-stairs, as if pushed with the tip
of the finger. Sensation as if the heart beat in the pit of the stomach.
Painful stitch at the heart, shifting to the right side. Stitch at the
heart, which seems to beat slowly. The beats of the heart are not felt in
the morning, in bed. Drawing pain from the front part of the neck to the
ear. Pulling from the lower jaw to the middle of the neck. Boring pain at
the right external carotid. The neck is so painful that the turning the
head is difficult and painful. Weakness of the lumbar region.
EXTREMITIES: Rheumatic pain in left shoulder-blade. Pain in the back and
chest. Pain in the left arm, in the morning. Redness at the left arm.
Dull crampy pain in right elbow, shifting to the left. Pulling from the
forearm to the right little finger. Pain from the left elbow through
the forearm. Bruising pain in the bones of the right forearm, with
lancination. Dull pain from the wrist-joint to the middle of the forearm.
Red spot with a yellowish pellicle on the wrists. Drawing in the flexor
communis digitorum. Red, itching spot on the ring-finger. Sense as of
thorns between the thighs when walking. Ulcers on the legs. Pain in the
right leg. Weakness of the legs. Bruising pain in the legs. Rheumatic
pain in the right calf. Rheumatic pain in right knee, disappearing by
motion. Bruising pain in the right knee.
SLEEP: No sleep at night. Dreams about a frightful storm, mountains
from which smoke issues, &c. Restless sleep, with frightful dreams.
Dreams about combats, calcined head, which spoke to him angrily, &c.
Loud dreams. Fever. Internal chilliness. Dryness and prickings all over.
Weariness of the limbs. Weakness in the morning. Weary while talking.
Malaise, nausea, debility. Stiffness of the loins, and bruising pain in
the abdomen and hypochondria. Pains in the joints. Prostration; he is
easily tired. Weary in the evening.
CANNA ANGUSTIFOLIA.
C. ANG. CANNA GLAUCA. PORTUG.: IMBIRI.
This plant inhabits damp regions, or the borders of brooks. Its stem
is erect, cylindrical, growing to a height of about six feet out of a
rhizoma sending off numerous rootlets. It is provided with knots, whence
arise large alternate clasping leaves, whose lanceolate limbs have strong
midribs, sending off fine parallel transverse nerves. At its summit the
stem bears the flower-bearing pedicels. Flowers alternate, on short
peduncles, and accompanied by bracts. The corol has a double perianth,
with three divisions adhering to the triangular, greenish and glandular
ovary; the stamens present the changing characters so common in this
family. We use the leaves.
An infusion of the leaves was recommended for the lepra; but this
empirical application of the drug has been abandoned. 1. Whitish
expectoration in the morning. Numbness at the instep. He dreams about
doctors, treatment. Vertigo on waking. 5. Heat at the anus. Lancinations
at the feet, legs and hands. Pain in the chest. Swelling of the fingers.
Weakness of sight. 10. Itching of the skin. Weariness in the chest.
Peeling off of the skin. Roughness in the throat. Excited sexual desire.
15. Too sudden emission of the semen, and without thrill. Heat at the
ears. Constipation.
HEDYSARUM ILDEFONSIANUM. (NOBIS.)
HED. DESMODIUM. PORTUG.: AMOR DO CAMPO. BARBA DE BOI. CARAPICHO. ENGL.:
BURDOCK.
The brownish and ligneous stem of this plant is about three feet high;
it is ramose, pubescent, especially above. Leaves alternate, pennate,
trifoliate; folioles oval and slightly tomentose, on a hairy, bistipulate
petiole. The flowers which are small and seated on filiform, unifloral
peduncles, form loose, terminal spikes. Fruit oval, hairy, on bent
peduncles, and attaching itself very intimately to clothes and to the
hairy skin of animals, on which account the Brazilians call it barba de
boi.
1. Painful tearing from the loins to the navel. This pain is less on the
second day. Sudden appearance of a yellowish discharge from the urethra.
No sleep for several nights. 5. Itching of the penis. Pain and pricking
at the eyes. The fingers contract with pain. Redness and smarting at
the penis. Diarrhœa. 10. Profuse urination. Pain in the upper and lower
limbs. Smarting in the eye, with lachrymation. Redness of the sclerotica.
Fever and rheumatic pains. 15. Constipation. Painful swelling of the
penis, with erysipelatous inflammation. Thin stream of the urine, in
consequence of the glans being swollen.
MYRISTICA SEBIFERA. (SWARTZ.)
MYR. VIROLA SEBIFERA (AUBLET). PORT.: UCUUBA.
This is a tree of some height, the trunk and branches of which are
covered with a thick, brownish and reticulate bark. Leaves alternate,
oblong, cordate, rather tomentose on their lower surface, and supported
by short petioles. Flowers in tufted panicles, ramose, arising from
the axil of the leaves or the extremities of the branches; they are
dioïchous, with a simple, urceolate perigone having three divisions.
Male flowers with six stamens, the filaments of which are attached to
each other, and are inserted in a glandular disk. The female flowers are
smaller, one unilocular, ovary, style wanting, stygma bilobed. Capsular
berry, with two valves, containing an oleaginous seed, surrounded by an
aril crenated above. This tree is found in the provinces of Para and
Rio-Negro. We use the red juice which is acrid and very poisonous and is
obtained by cutting into the bark.
_First day._—1. Vertigo from right to left, on waking in the morning.
Difficulty of swallowing the saliva. Constriction of the isthmus of the
pharynx; this pain increases progressively. Pain and pressure from within
outwards at the right frontal eminence. 5. This pain intermits now and
then and is less in the open air. Pain in the finger-nails, with swelling
of the phalanxes. Painful pinching in the right calf.
_Second day._—He is unable to fall asleep in the evening, in bed.
Confused dreams about houses which one is building, commencing at the
upper stories. 10. The buccal cavity, the tonsils and the upper part of
the pharynx are painful to contact, the soup, when chewing or swallowing
it, seems to make these parts sore. Burning sensation in the throat. The
urine is discharged less frequently. Dizziness, in the morning. He is
indifferent and careless in regard to his business. 15. Sensation as if
a foreign body, of the size of a walnut, had lodged in the interior of
the left inguinal region, the whole morning. The face is highly colored.
Tingling in the left thumb-joint. Stiff hands as from squeezing something
in one’s hands for a long time. Pain in the left hand; thirst. 20. He
swallows his saliva with less pain and more ease. The urine is scanty
and discharged less frequently, though he has drank a good deal; it is
of a reddish yellow. The pains in the hands increase when the hands are
joined. He is in the habit of drinking two tumblers of water before going
to bed, and he urinates immediately afterwards; on the second day he
drinks in the evening, but does not urinate. Pinching at the right side
of the neck.
_Third day._—25. Restless sleep, he dreams about violent quarrels. Marked
copper-taste in the mouth, followed by spitting of blood for 20 minutes.
No urine since 5 o’clock in the evening, on the second day. Since 4 in
the afternoon he has been unable to fix his mind upon any one point; he
continually repeats in his mind a tune, which irritates him, and of which
he cannot rid himself. The whole mouth is painful. 30. Two pimples on the
left cheek, they disappear in an hour.
_Fourth day._—At night, hard pressure in the sides of the thorax, though
this does not hinder the breathing. Restless sleep, with dreams about
occupations that are entirely different from his ordinary business;
afterwards dreams about disputes. Tongue white-coated and cracked. His
head feels heavy. 35. Stools mixed with yellow mucus. Bitter mouth.
Palate insensible, with loss of taste.
_Fifth day._—Restless sleep. Violent starting during sleep. 40. Pain at
the frontal eminence, at noon. He is unable to concentrate his attention
on one object, though he has important business to attend to.
ARRANGEMENT ACCORDING TO HAHNEMANN.
Indifferent and careless about business. He keeps repeating a tune
against his will; this irritates him. Quarrelsome dreams. Is unable to
fix his mind. Vertigo from right to left. Painful pressure at frontal
eminence from within outwards. Pain at the frontal eminences. Pimples on
the left cheek. Coppery taste in the mouth. Constriction of the pharynx,
painful. Soreness of the mouth, tonsils and pharynx. Tongue white-coated
and cracked. Difficulty of swallowing saliva. Sensation as if a small
body had lodged in the left inguinal region. Stools mixed with yellow
mucus. Scanty urine, with less frequent discharges. Hard pressures in
the sides of the thorax, at night. Pinching at the right side of the
neck. Stiffness of the hands. Tingling in left thumb-joint. Pain at the
finger-nails, with swelling of the phalanxes. Painful pinching in right
calf. Confused dreams about building houses. No sleep in the evening.
OCIMUM CANUM. (D. C.)
OCIM. OCIMUM INCANESCENS (Mart.) OCIMUM FLUMINENSE (WELLS.) PORTUG.:
ALFAVACA.
This is an herbaceous plant having an aromatic odor, with an erect and
ramose stem, about 16 or 20 inches high; it is pubescent, quadrangular
and grooved towards the upper branches. Leaves opposite, oval, finely
indented, on petioles of the same length, as the limbs of the leaves.
Flowers whorled, forming terminal spikes; each whorl is provided with
two foliaceous bracts. Calix with five divisions, the upper being oval,
large and entire; the other four are sharp and inferior. Corol tubulous,
inverted, with a bilabiate limb; the upper lip divided into four lobes;
the lower lip composed of a single lobe, which is longer. Stamens four,
with free and outward-bent filaments, and two other stamens, which are
shorter and somewhat geniculate at their base; style filiform and bifid.
Root vertical, fibrous, rather ramose. We use the leaves.
The ocimum canum is destined to become one of the most important remedial
agents in Brazil, where it is used as a specific for the diseases of the
kidneys, bladder and urethra. Those who wish to devote themselves to our
art, had better set about proving this drug.
1. Turbid urine, depositing a white and albuminous sediment. Burning
during micturition. Urine of a saffron color. Diarrhœa, several attacks
a day. 5. Crampy pain in the kidneys. Renal colic, with violent vomiting
every 15 minutes; one wrings one’s hands, and moans and cries all the
time. Red urine with brick-dust sediment after the attack. Itching at the
breasts. Engorgement of the mammary glands. 10. The tips of the breasts
are very painful; the least contact extorts a cry. Compressive pain in
the breast, as is the case with wet-nurses. Dreams about being poisoned.
Dreams about her parents, friends, children. Lancinations in the labia
majora. Swelling of the whole vulva. 15. Falling of the vagina, so as to
issue even from the vulva. Thick, purulent urine, with an intolerable
smell of musk. Swelling of the inguinal glands. Heat, swelling and
excessive sensibility of the left testicle. Numbness of the right thigh,
for two days.
SOLANUM ARREBENTA. (VELL.)
SOL. AR. PORTUG.: ARREBENTA CAVALLOS.
This bush grows spontaneously in the provinces of Rio Janeiro, along
roads and in cultivated places. It is from 10 to 16 inches high; its
branches which bifurcate regularly, are, while young, covered with strong
thorns growing from above downwards. Leaves slightly pubescent, cordate,
with five obtuse lobes; their nerves are furnished with a few irregularly
distributed thorns. The flowers are supported by peduncles arising from
the axils of the leaves in groups of two or three. Calix with five parts,
very prickly on the outside; corol with five divisions; five stamens; a
style. Berry red, fleshy, with two chambers, containing a large number
of small seeds. Roots fibrous, arising from a common rhizoma. We use the
leaves.
1. Loss of appetite. Superficial ulceration below the left nipple.
Vertigo after bathing. Painful boil below the right axilla. 5. Pain at
the pectoralis major. Suppuration of the boils. Headache. Slight fever.
Swelling of the stomach. 10. Difficult digestion. Urticaria. Dreams about
quarrels and murders. Waking with a start. Doughy mouth in the morning.
15. Constant thirst. Impatient and irritated by trifling causes. Redness
of the face, and rush of blood to the brain. Flash of heat all over.
Paleness and greenish color of the skin after a few days of proving. 20.
Swelling of the axillary glands. Lancinations in the breasts. Glandular
tumor in the right breast.
ILLICIUM ANISATUM.
ANISUM STELLATUM.
Both the illicium anisatum and the millefolium, which have been
introduced into our practice empirically, will undoubtedly become
important adjuncts in the homœopathic materia medica, the former in
gastric affections, the latter in those of the chest. We publish the
following symptoms in the hope of facilitating their employment in the
treatment of disease.
1. Dizziness. Buzzing in the ears. Ringing in the ears, followed by
sleep. Bloating of the stomach. 5. Retention of urine. Pain in the loins.
Bilious stools. Acute catarrh. Constipation. 10. Pain in the spleen. Heat
from the abdomen to the stomach and chest, shifting about here and there,
and decreases in the course of the day. 15. Rumbling in the abdomen. Acid
stomach. Satiety after eating but little. Nausea. Uncertain pains in the
head. The pains are less in the evening and worse in the morning. Flow of
saliva. Watery discharge from the nostrils. 20. The stools are compact
and dark-colored. Drowsy at twilight. Pain at the spleen. Heat at the
navel and in the œsophagus. Violent erections. Nocturnal emissions. 25.
Pains in the chest, also the left side, and feeling of emptiness after
coughing. Pain in the back and chest. White expectoration. Disturbed
sleep.
MILLEFOLIUM.
_Second day._—1. Headache as if the skull would fly to pieces. Stitches
in the chest. Oppression, dyspnœa. Burning eyes. 5. Tongue coated and
swollen. Urine red, frequent and copious.
_Third day._—Headache less violent. Prostration. Malaise in all the
limbs. 10. Dry mouth. Lips cracked. Stomach-ache. Cough with frothy
expectoration. Cough and vomiting. 15. Fever with shuddering, internal
and external heat, for four hours. Hot fever. Thirst. Hot hands and feet.
FOOTNOTES
[1] This case has been reported in detail, in the Medical Gazette of
Paris, of the 5th of January, 1839, by the attending physicians, _Maïa_
and _Reis_. We transcribe it for the benefit of our readers.
Mariano José Machado, fifty years old, of athletic form, bilious-sanguine
temperament, was afflicted with elephantiasis leontina Alibert. The whole
body, especially the extremities, were insensible. The skin and the
cellular tissue were thickened, hard, rugose and covered with tubercles
which were somewhat raised but not ulcerated. A few pustules under the
arms, looked like itch-pustules, and seemed to indicate a complication
with this disease. The epidermis and nails began to alter, and the
fingers had lost their normal shape. Internally, the patient felt quite
well, enjoying both vigor of mind and body. After six years of suffering,
he had come to the determination to try this dreadful experiment, which
would either lead to death or a deliverance from his horrible affliction.
On the morning of the fourth of September, at fifty minutes past eleven
o’clock, he was bit by a rattle-snake, the crotalus cascavella, in
the two last fingers near the metacarpus. He felt neither the bite,
nor the poison as it penetrated into the wound. A few drops of blood
came out of the wound, and the hand began immediately to swell.—In
five minutes: slight feeling of coldness in the hands.—Twelve o’clock:
slight pain in the hollow of the hands.—Twenty minutes: the hand swells
a good deal.—Thirty minutes: swelling of the jugular veins. Alteration
of the features. Formication in the face.—Fifty-five minutes: the
sense of swelling extends through the whole forearm.—Twenty minutes
past one: trembling of the whole body.—Thirty-six minutes past one:
the head is affected, with frequent pulse, difficulty of moving the
lips, disposition to slumber, constriction of the throat, violent pain
in the whole arm, the hand swells more and more.—Thirty-eight minutes
past one: sense of chilliness; the patient covers himself.—Forty-eight
minutes past one: pain in the tongue and larynx, increased pains and
swelling of the bitten hand; sense of coldness in the feet.—Twenty-five
minutes past two: difficulty of swallowing,—anguish,—copious sweat on
the chest.—Fifty minutes: weakness of the arms,—nosebleed,—anguish,
now and then,—restlessness,—pulse 96.—In three hours and forty
minutes: pulse 100.—Fifteen minutes: intensely violent pains in the
arms.—restlessness.—Thirty minutes: pulse 98,—red face,—continual
bleeding of the nose.—Thirty-five minutes: the patient drinks some wine
and water without any difficulty, and changes his linen which was all
wet from the perspiration.—Intense redness all over.—In four hours:
pulse 100,—the whole of the skin, especially on the bitten arm, is
very red,—violent pains in both arms, which do not leave the patient
any rest,—constriction of the throat,—impeded respiration.—Fifty
minutes: pulse 104,—the body is very hot all over,—flow of saliva.—In
five hours, thirty minutes: torpor,—copious emission of urine,—thick,
viscid saliva, which it is difficult to get out of the mouth,—muscular
debility,—frequent moaning on account of the pains which he feels
in the whole body,—quiet breathing,—pulse full and frequent, skin
soft,—the bitten hand swells enormously.—In seven hours: somnolence
with moaning,—after waking the pains in the arms are less, but he
experiences violent pains in the chest,—sensation of a lump in his
throat,—copious emission of urine,—great difficulty of swallowing, white,
viscid saliva,—discharge of a bloody liquid from the nose,—inability to
swallow a drink composed of water, sugar and brandy.—In eight hours:
the sweating abates,—restlessness,—moaning,—emission of urine.—In nine
hours, ten minutes: the moaning ceases,—deep sleep.—In ten hours: takes
an infusion of guaco,—pulse 108,—the bloody discharge from the nose
ceases,—shrivelling of the tuberculous formations on the arms and in
the face, they exhibit an erysipelatous redness.—In ten hours, twenty
minutes: emits two ounces of a natural urine,—a few minutes’ quiet
sleep, without moaning.—In ten hours, forty minutes: the pains abate
a good deal, but he complains of pains in the thighs and feet, where
he had felt a considerable coldness until now,—pulse 108,—ordinary
thirst,—the patient sits up in order to drink, and swallows the drink
with ease.—In eleven hours: takes four spoonfuls of a strong infusion
of guaco.—In eleven hours, forty-five minutes: emits a deeply-colored
urine,—pulse 119,—the bitten hand and arm are very much inflamed and
intensely painful,—restlessness.—In twelve hours: quiet sleep, disturbed
by eructations,—pulse 112,—emission of urine.—In twelve hours, thirty
minutes: restlessness,—screams,—despair.—In twelve hours, forty minutes:
emission of urine,—pulse 116,—sensation of burning heat in the legs,
which he uncovers.—In thirteen hours: emission of urine,—quiet,—he takes
an infusion of guaco.—In fourteen hours: he sits up in bed, and drinks
water, during which he moves about violently and screams.—In fifteen
hours: emission of urine,—the swelling of the lower lips abates,—the
salivation ceases.—In fifteen hours, forty-five minutes: pulse
110,—involuntary motion of the right thumb and left foot.—In seventeen
hours: the patient feels very sick,—pulse 100,—frequent moaning.—In
nineteen hours: excessive debility,—involuntary motion of the lower
jaw, and lower extremities,—bloody urine.—In twenty hours: accelerated,
intermitting pulse,—increase of the convulsive motions,—the swelling of
the extremities, and the redness of the skin are less,—extreme difficulty
of swallowing,—anxious respiration.—In twenty hours, fifty minutes:
diminution of the convulsive motions.—In twenty hours, fifty-five
minutes: the convulsions cease.—In twenty-one hours: he takes an ounce
of lizard-oil, which he swallows with difficulty.—In twenty-one hours,
thirty minutes: death.—In a few minutes, the blue-colored body, swoll
considerably.—Twenty-three hours after death, the body had swollen
enormously, was covered with blue and red spots, and smelt so horridly
that no post-mortem examination could be made.—HEMPEL.
[2] To avoid unnecessary repetition, the natural order of the
symptoms has been left out, it being nearly the same as Hahnemann’s
arrangement—_Ed._
TABLE OF CONTENTS.
Page.
Introduction, 3
Crotalus Cascavella, 5
Elaps Corallinus, 22
Pediculus Capitis, 40
Eleis Guineensis, 45
Mimosa Humilis, 49
Cervus Brazilicus, 51
Guano Australis, 54
Hippomane Mancinella, 57
Hura Braziliensis, 65
Lepidium Bonariense, 101
Panacea, 115
Solanum Tuberosum Ægrotans, 117
Plumbago Littoralis, 138
Solanum Oleraceum, 142
Paullinia Pinnata, 144
Blatta Americana, 151
Delphinus Amazonicus, 153
Amphisbœna Vermicularis, 155
Aristolochia Milhomens, 157
Resina Itu, 162
Tradescantia Diuretica, 165
Murure Leite, 166
Cannabis Indica, 168
Petiveria Tetrandra, 170
Janipha Manihot, 182
Melastoma Ackermani, 185
Sedinha, 187
Spiggurus Martini, 188
Convolvulus Duartinus, Morning Glory, 192
Bufo Sahytiensis, Toad, 195
Jacaranda Caroba, 199
Canna Angustifolia, 209
Hedysarum Ildefonsianum, (Burdock), 210
Myristica Sebifera, 211
Ocimum Canum, 214
Solanum Arrebenta, 216
Illicium Anisatum, 217
Millefolium, 218 | 83,487 | common-pile/project_gutenberg_filtered | 70350 | project gutenberg | project_gutenberg-dolma-0013.json.gz:1724 | https://www.gutenberg.org/ebooks/70350.txt.utf-8 |
0p2Cw3UP8mQhDyQQ | 9.9: Exercises | Why not?
Prepare a table identifying several energy transitions that take place during the typical operation of an automobile.
Explain the difference between heat capacity and specific heat of a substance.
Calculate the heat capacity, in joules and in calories per degree, of the following:
(a) 28.4 g of water
(b) 1.00 oz of lead
Calculate the heat capacity, in joules and in calories per degree, of the following:
(a) 45.8 g of nitrogen gas
(b) 1.00 pound of aluminum metal
How much heat, in joules and in calories, must be added to a 75.0–g iron block with a specific heat of 0.449 J/g °C to increase its temperature from 25 °C to its melting temperature of 1535 °C?
How much heat, in joules and in calories, is required to heat a 28.4-g (1-oz) ice cube from −23.0 °C to −1.0 °C?
How much would the temperature of 275 g of water increase if 36.5 kJ of heat were added?
If 14.5 kJ of heat were added to 485 g of liquid water, how much would its temperature increase?
A piece of unknown substance weighs 44.7 g and requires 2110 J to increase its temperature from 23.2 °C to 89.6 °C.
(a) What is the specific heat of the substance?
(b) If it is one of the substances found in Table 9.1, what is its likely identity?
A piece of unknown solid substance weighs 437.2 g, and requires 8460 J to increase its temperature from 19.3 °C to 68.9 °C.
(a) What is the specific heat of the substance?
(b) If it is one of the substances found in Table 9.1, what is its likely identity?
An aluminum kettle weighs 1.05 kg.
(a) What is the heat capacity of the kettle?
(b) How much heat is required to increase the temperature of this kettle from 23.0 °C to 99.0 °C?
(c) How much heat is required to heat this kettle from 23.0 °C to 99.0 °C if it contains 1.25 L of water (density of 0.997 g/mL and a specific heat of 4.184 J/g °C)?
Most people find waterbeds uncomfortable unless the water temperature is maintained at about 85 °F. Unless it is heated, a waterbed that contains 892 L of water cools from 85 °F to 72 °F in 24 hours. Estimate the amount of electrical energy required over 24 hours, in kWh, to keep the bed from cooling. Note that 1 kilowatt-hour (kWh) = 3.6 10 6 J, and assume that the density of water is 1.0 g/mL (independent of temperature). What other assumptions did you make? How did they affect your calculated result (i.e., were they likely to yield “positive” or “negative” errors)?
A 500-mL bottle of water at room temperature and a 2-L bottle of water at the same temperature were placed in a refrigerator. After 30 minutes, the 500-mL bottle of water had cooled to the temperature of the refrigerator. An hour later, the 2-L of water had cooled to the same temperature. When asked which sample of water lost the most heat, one student replied that both bottles lost the same amount of heat because they started at the same temperature and finished at the same temperature. A second student thought that the 2-L bottle of water lost more heat because there was more water. A third student believed that the 500-mL bottle of water lost more heat because it cooled more quickly. A fourth student thought that it was not possible to tell because we do not know the initial temperature and the final temperature of the water. Indicate which of these answers is correct and describe the error in each of the other answers.
Would the amount of heat measured for the reaction in Example 9.5 be greater, lesser, or remain the same if we used a calorimeter that was a poorer insulator than a coffee cup calorimeter? Explain your answer.
Would the amount of heat absorbed by the dissolution in Example 9.6 appear greater, lesser, or remain the same if the experimenter used a calorimeter that was a poorer insulator than a coffee cup calorimeter? Explain your answer.
Would the amount of heat absorbed by the dissolution in Example 9.6 appear greater, lesser, or remain the same if the heat capacity of the calorimeter were taken into account? Explain your answer.
How many milliliters of water at 23 °C with a density of 1.00 g/mL must be mixed with 180 mL (about 6 oz) of coffee at 95 °C so that the resulting combination will have a temperature of 60 °C? Assume that coffee and water have the same density and the same specific heat.
How much will the temperature of a cup (180 g) of coffee at 95 °C be reduced when a 45 g silver spoon (specific heat 0.24 J/g °C) at 25 °C is placed in the coffee and the two are allowed to reach the same temperature? Assume that the coffee has the same density and specific heat as water.
A 45-g aluminum spoon (specific heat 0.88 J/g °C) at 24 °C is placed in 180 mL (180 g) of coffee at 85 °C and the temperature of the two become equal.
(a) What is the final temperature when the two become equal? Assume that coffee has the same specific heat as water.
(b) The first time a student solved this problem she got an answer of 88 °C. Explain why this is clearly an incorrect answer.
The temperature of the cooling water as it leaves the hot engine of an automobile is 240 °F. After it passes through the radiator it has a temperature of 175 °F. Calculate the amount of heat transferred from the engine to the surroundings by one gallon of water with a specific heat of 4.184 J/g °C.
A 70.0-g piece of metal at 80.0 °C is placed in 100 g of water at 22.0 °C contained in a calorimeter like that shown in Figure 9.12. The metal and water come to the same temperature at 24.6 °C. How much heat did the metal give up to the water? What is the specific heat of the metal?
If a reaction produces 1.506 kJ of heat, which is trapped in 30.0 g of water initially at 26.5 °C in a calorimeter like that in Figure 9.12, what is the resulting temperature of the water?
A 0.500-g sample of KCl is added to 50.0 g of water in a calorimeter (Figure 9.12). If the temperature decreases by 1.05 °C, what is the approximate amount of heat involved in the dissolution of the KCl, assuming the specific heat of the resulting solution is 4.18 J/g °C? Is the reaction exothermic or endothermic?
Dissolving 3.0 g of CaCl 2 ( s ) in 150.0 g of water in a calorimeter (Figure 9.12) at 22.4 °C causes the temperature to rise to 25.8 °C. What is the approximate amount of heat involved in the dissolution, assuming the specific heat of the resulting solution is 4.18 J/g °C? Is the reaction exothermic or endothermic?
When 50.0 g of 0.200 M NaCl( aq ) at 24.1 °C is added to 100.0 g of 0.100 M AgNO 3 ( aq ) at 24.1 °C in a calorimeter, the temperature increases to 25.2 °C as AgCl( s ) forms. Assuming the specific heat of the solution and products is 4.20 J/g °C, calculate the approximate amount of heat in joules produced.
The addition of 3.15 g of Ba(OH) 2 ·8H 2 O to a solution of 1.52 g of NH 4 SCN in 100 g of water in a calorimeter caused the temperature to fall by 3.1 °C. Assuming the specific heat of the solution and products is 4.20 J/g °C, calculate the approximate amount of heat absorbed by the reaction, which can be represented by the following equation:
Ba(OH) 2 ·8H 2 O( s ) + 2NH 4 SCN( aq ) ⟶ Ba(SCN) 2 ( aq ) + 2NH 3 ( aq ) + 10H 2 O( l )
The reaction of 50 mL of acid and 50 mL of base described in Example 9.5 increased the temperature of the solution by 6.9 ºC. How much would the temperature have increased if 100 mL of acid and 100 mL of base had been used in the same calorimeter starting at the same temperature of 22.0 ºC? Explain your answer.
If the 3.21 g of NH 4 NO 3 in Example 9.6 were dissolved in 100.0 g of water under the same conditions, how much would the temperature change? Explain your answer.
When 1.0 g of fructose, C 6 H 12 O 6 ( s ), a sugar commonly found in fruits, is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 1.58 °C. If the heat capacity of the calorimeter and its contents is 9.90 kJ/°C, what is q for this combustion?
When a 0.740-g sample of trinitrotoluene (TNT), C 7 H 5 N 2 O 6 , is burned in a bomb calorimeter, the temperature increases from 23.4 °C to 26.9 °C. The heat capacity of the calorimeter is 534 J/°C, and it contains 675 mL of water. How much heat was produced by the combustion of the TNT sample?
One method of generating electricity is by burning coal to heat water, which produces steam that drives an electric generator. To determine the rate at which coal is to be fed into the burner in this type of plant, the heat of combustion per ton of coal must be determined using a bomb calorimeter. When 1.00 g of coal is burned in a bomb calorimeter (Figure 9.17), the temperature increases by 1.48 °C. If the heat capacity of the calorimeter is 21.6 kJ/°C, determine the heat produced by combustion of a ton of coal (2.000 10 3 pounds).
The amount of fat recommended for someone with a daily diet of 2000 Calories is 65 g. What percent of the calories in this diet would be supplied by this amount of fat if the average number of Calories for fat is
9.1 Calories/g?
A teaspoon of the carbohydrate sucrose (common sugar) contains 16 Calories (16 kcal). What is the mass of one teaspoon of sucrose if the average number of Calories for carbohydrates is 4.1 Calories/g?
What is the maximum mass of carbohydrate in a 6-oz serving of diet soda that contains less than 1 Calorie per can if the average number of Calories for carbohydrates is 4.1 Calories/g?
A pint of premium ice cream can contain 1100 Calories. What mass of fat, in grams and pounds, must be produced in the body to store an extra 1.1
10
3
Calories if the average number of Calories for fat is
9.1 Calories/g?
A serving of a breakfast cereal contains 3 g of protein, 18 g of carbohydrates, and 6 g of fat. What is the Calorie content of a serving of this cereal if the average number of Calories for fat is 9.1 Calories/g, for carbohydrates is 4.1 Calories/g, and for protein is 4.1 Calories/g?
Which is the least expensive source of energy in kilojoules per dollar: a box of breakfast cereal that weighs 32 ounces and costs $4.23, or a liter of isooctane (density, 0.6919 g/mL) that costs $0.45? Compare the nutritional value of the cereal with the heat produced by combustion of the isooctane under standard conditions. A 1.0-ounce serving of the cereal provides 130 Calories.
Explain how the heat measured in Example 9.5 differs from the enthalpy change for the exothermic reaction described by the following equation:
Using the data in the check your learning section of Example 9.5, calculate Δ H in kJ/mol of AgNO 3 ( aq ) for the reaction:
Calculate the enthalpy of solution (Δ H for the dissolution) per mole of NH 4 NO 3 under the conditions described in Example 9.6.
Calculate Δ
H
for the reaction described by the equation. (
Hint
: Use the value for the approximate amount of heat absorbed by the reaction that you calculated in a previous exercise.)
Calculate the enthalpy of solution (Δ H for the dissolution) per mole of CaCl 2 (refer to Exercise 9.25).
Although the gas used in an oxyacetylene torch (Figure 9.7) is essentially pure acetylene, the heat produced by combustion of one mole of acetylene in such a torch is likely not equal to the enthalpy of combustion of acetylene listed in Table 9.2. Considering the conditions for which the tabulated data are reported, suggest an explanation.
How much heat is produced by burning 4.00 moles of acetylene under standard state conditions?
How much heat is produced by combustion of 125 g of methanol under standard state conditions?
How many moles of isooctane must be burned to produce 100 kJ of heat under standard state conditions?
What mass of carbon monoxide must be burned to produce 175 kJ of heat under standard state conditions?
When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?
How much heat is produced when 100 mL of 0.250 M HCl (density, 1.00 g/mL) and 200 mL of 0.150 M NaOH (density, 1.00 g/mL) are mixed?
If both solutions are at the same temperature and the specific heat of the products is 4.19 J/g °C, how much will the temperature increase? What assumption did you make in your calculation?
A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 °C to 27.93 °C. What is the heat capacity of the calorimeter and its contents?
Before the introduction of chlorofluorocarbons, sulfur dioxide (enthalpy of vaporization, 6.00 kcal/mol) was used in household refrigerators. What mass of SO 2 must be evaporated to remove as much heat as evaporation of 1.00 kg of CCl 2 F 2 (enthalpy of vaporization is 17.4 kJ/mol)?
The vaporization reactions for SO 2 and CCl 2 F 2 are and respectively.
Homes may be heated by pumping hot water through radiators. What mass of water will provide the same amount of heat when cooled from 95.0 to 35.0 °C, as the heat provided when 100 g of steam is cooled from 110 °C to 100 °C.
Which of the enthalpies of combustion in Table 9.2 the table are also standard enthalpies of formation?
Does the standard enthalpy of formation of H 2 O( g ) differ from Δ H ° for the reaction
Joseph Priestly prepared oxygen in 1774 by heating red mercury(II) oxide with sunlight focused through a lens. How much heat is required to decompose exactly 1 mole of red HgO( s ) to Hg( l ) and O 2 ( g ) under standard conditions?
How many kilojoules of heat will be released when exactly 1 mole of manganese, Mn, is burned to form Mn 3 O 4 ( s ) at standard state conditions?
How many kilojoules of heat will be released when exactly 1 mole of iron, Fe, is burned to form Fe 2 O 3 ( s ) at standard state conditions?
The following sequence of reactions occurs in the commercial production of aqueous nitric acid:
Determine the total energy change for the production of one mole of aqueous nitric acid by this process.
Both graphite and diamond burn.
For the conversion of graphite to diamond:
Which produces more heat, the combustion of graphite or the combustion of diamond?
From the molar heats of formation in Appendix G, determine how much heat is required to evaporate one mole of water:
Which produces more heat?
or
for the phase change
Calculate
for the process
from the following information:
Calculate for the process
from the following information:
Calculate Δ H for the process
from the following information:
Calculate for the process
from the following information:
Calculate the standard molar enthalpy of formation of NO(
g
) from the following data:
Using the data in Appendix G, calculate the standard enthalpy change for each of the following reactions:
(a)
(b)
(c)
(d)
Using the data in Appendix G, calculate the standard enthalpy change for each of the following reactions:
(a)
(b)
(c)
(d)
The following reactions can be used to prepare samples of metals. Determine the enthalpy change under standard state conditions for each.
(a)
(b)
(c)
(d)
The decomposition of hydrogen peroxide, H
2
O
2
, has been used to provide thrust in the control jets of various space vehicles. Using the data in Appendix G, determine how much heat is produced by the decomposition of exactly 1 mole of H
2
O
2
under standard conditions.
Calculate the enthalpy of combustion of propane, C 3 H 8 ( g ), for the formation of H 2 O( g ) and CO 2 ( g ). The enthalpy of formation of propane is −104 kJ/mol.
Calculate the enthalpy of combustion of butane, C 4 H 10 ( g ) for the formation of H 2 O( g ) and CO 2 ( g ). The enthalpy of formation of butane is −126 kJ/mol.
Both propane and butane are used as gaseous fuels. Which compound produces more heat per gram when burned?
The white pigment TiO 2 is prepared by the reaction of titanium tetrachloride, TiCl 4 , with water vapor in the gas phase:
How much heat is evolved in the production of exactly 1 mole of TiO 2 ( s ) under standard state conditions?
Water gas, a mixture of H 2 and CO, is an important industrial fuel produced by the reaction of steam with red hot coke, essentially pure carbon:
(a) Assuming that coke has the same enthalpy of formation as graphite, calculate for this reaction.
(b) Methanol, a liquid fuel that could possibly replace gasoline, can be prepared from water gas and additional hydrogen at high temperature and pressure in the presence of a suitable catalyst:
Under the conditions of the reaction, methanol forms as a gas. Calculate for this reaction and for the condensation of gaseous methanol to liquid methanol.
(c) Calculate the heat of combustion of 1 mole of liquid methanol to H 2 O( g ) and CO 2 ( g ).
In the early days of automobiles, illumination at night was provided by burning acetylene, C
2
H
2
. Though no longer used as auto headlamps, acetylene is still used as a source of light by some cave explorers. The acetylene is (was) prepared in the lamp by the reaction of water with calcium carbide, CaC
2
:
Calculate the standard enthalpy of the reaction. The
of CaC
2
is −15.14 kcal/mol.
From the data in Table 9.2, determine which of the following fuels produces the greatest amount of heat per gram when burned under standard conditions: CO( g ), CH 4 ( g ), or C 2 H 2 ( g ).
The enthalpy of combustion of hard coal averages −35 kJ/g, that of gasoline, 1.28 10 5 kJ/gal. How many kilograms of hard coal provide the same amount of heat as is available from 1.0 gallon of gasoline? Assume that the density of gasoline is 0.692 g/mL (the same as the density of isooctane).
Ethanol, C 2 H 5 OH, is used as a fuel for motor vehicles, particularly in Brazil.
(a) Write the balanced equation for the combustion of ethanol to CO 2 ( g ) and H 2 O( g ), and, using the data in Appendix G, calculate the enthalpy of combustion of 1 mole of ethanol.
(b) The density of ethanol is 0.7893 g/mL. Calculate the enthalpy of combustion of exactly 1 L of ethanol.
(c) Assuming that an automobile’s mileage is directly proportional to the heat of combustion of the fuel, calculate how much farther an automobile could be expected to travel on 1 L of gasoline than on 1 L of ethanol. Assume that gasoline has the heat of combustion and the density of n–octane, C 8 H 18 density = 0.7025 g/mL).
Among the substances that react with oxygen and that have been considered as potential rocket fuels are diborane [B 2 H 6 , produces B 2 O 3 ( s ) and H 2 O( g )], methane [CH 4 , produces CO 2 ( g ) and H 2 O( g )], and hydrazine [N 2 H 4 , produces N 2 ( g ) and H 2 O( g )]. On the basis of the heat released by 1.00 g of each substance in its reaction with oxygen, which of these compounds offers the best possibility as a rocket fuel? The
How much heat is produced when 1.25 g of chromium metal reacts with oxygen gas under standard conditions?
Ethylene, C 2 H 4 , a byproduct from the fractional distillation of petroleum, is fourth among the 50 chemical compounds produced commercially in the largest quantities. About 80% of synthetic ethanol is manufactured from ethylene by its reaction with water in the presence of a suitable catalyst.
Using the data in the table in Appendix G, calculate Δ H ° for the reaction.
The oxidation of the sugar glucose, C
6
H
12
O
6
, is described by the following equation:
The metabolism of glucose gives the same products, although the glucose reacts with oxygen in a series of steps in the body.
(a) How much heat in kilojoules can be produced by the metabolism of 1.0 g of glucose?
(b) How many Calories can be produced by the metabolism of 1.0 g of glucose?
Propane, C 3 H 8 , is a hydrocarbon that is commonly used as a fuel.
(a) Write a balanced equation for the complete combustion of propane gas.
(b) Calculate the volume of air at 25 °C and 1.00 atmosphere that is needed to completely combust 25.0 grams of propane. Assume that air is 21.0 percent O 2 by volume. (Hint: We will see how to do this calculation in a later chapter on gases—for now use the information that 1.00 L of air at 25 °C and 1.00 atm contains 0.275 g of O 2 .)
(c) The heat of combustion of propane is −2,219.2 kJ/mol. Calculate the heat of formation, of propane given that of H 2 O( l ) = −285.8 kJ/mol and of CO 2 ( g ) = −393.5 kJ/mol.
(d) Assuming that all of the heat released in burning 25.0 grams of propane is transferred to 4.00 kilograms of water, calculate the increase in temperature of the water.
During a recent winter month in Sheboygan, Wisconsin, it was necessary to obtain 3500 kWh of heat provided by a natural gas furnace with 89% efficiency to keep a small house warm (the efficiency of a gas furnace is the percent of the heat produced by combustion that is transferred into the house).
(a) Assume that natural gas is pure methane and determine the volume of natural gas in cubic feet that was required to heat the house. The average temperature of the natural gas was 56 °F; at this temperature and a pressure of 1 atm, natural gas has a density of 0.681 g/L.
(b) How many gallons of LPG (liquefied petroleum gas) would be required to replace the natural gas used? Assume the LPG is liquid propane [C 3 H 8 : density, 0.5318 g/mL; enthalpy of combustion, 2219 kJ/mol for the formation of CO 2 ( g ) and H 2 O( l )] and the furnace used to burn the LPG has the same efficiency as the gas furnace.
(c) What mass of carbon dioxide is produced by combustion of the methane used to heat the house?
(d) What mass of water is produced by combustion of the methane used to heat the house?
(e) What volume of air is required to provide the oxygen for the combustion of the methane used to heat the house? Air contains 23% oxygen by mass. The average density of air during the month was 1.22 g/L.
(f) How many kilowatt–hours (1 kWh = 3.6 10 6 J) of electricity would be required to provide the heat necessary to heat the house? Note electricity is 100% efficient in producing heat inside a house.
(g) Although electricity is 100% efficient in producing heat inside a house, production and distribution of electricity is not 100% efficient. The efficiency of production and distribution of electricity produced in a coal-fired power plant is about 40%. A certain type of coal provides 2.26 kWh per pound upon combustion. What mass of this coal in kilograms will be required to produce the electrical energy necessary to heat the house if the efficiency of generation and distribution is 40%?
Which bond in each of the following pairs of bonds is the strongest?
(a) C–C or
(b) C–N or
(c) or
(d) H–F or H–Cl
(e) C–H or O–H
(f) C–N or C–O
Using the bond energies in Table 9.3, determine the approximate enthalpy change for each of the following reactions:
(a)
(b)
(c)
Using the bond energies in Table 9.3, determine the approximate enthalpy change for each of the following reactions:
(a)
(b)
(c)
Draw a curve that describes the energy of a system with H and Cl atoms at varying distances. Then, find the minimum energy of this curve two ways.
(a) Use the bond energy found in Table 9.3 and Table 9.4 to calculate the energy for one single HCl bond (Hint: How many bonds are in a mole?)
(b) Use the enthalpy of reaction and the bond energies for H 2 and Cl 2 to solve for the energy of one mole of HCl bonds.
Explain why bonds occur at specific average bond distances instead of the atoms approaching each other infinitely close.
When a molecule can form two different structures, the structure with the stronger bonds is usually the more stable form. Use bond energies to predict the correct structure of the hydroxylamine molecule:
How does the bond energy of HCl( g ) differ from the standard enthalpy of formation of HCl( g )?
Using the standard enthalpy of formation data in Appendix G, show how the standard enthalpy of formation of HCl( g ) can be used to determine the bond energy.
Using the standard enthalpy of formation data in Appendix G, calculate the bond energy of the carbon-sulfur double bond in CS 2 .
Using the standard enthalpy of formation data in Appendix G, determine which bond is stronger: the S–F bond in SF 4 ( g ) or in SF 6 ( g )?
Using the standard enthalpy of formation data in Appendix G, determine which bond is stronger: the P–Cl bond in PCl 3 ( g ) or in PCl 5 ( g )?
Complete the following Lewis structure by adding bonds (not atoms), and then indicate the longest bond:
Use the bond energy to calculate an approximate value of Δ H for the following reaction. Which is the more stable form of FNO 2 ?
Use principles of atomic structure to answer each of the following: 4
(a) The radius of the Ca atom is 197 pm; the radius of the Ca 2+ ion is 99 pm. Account for the difference.
(b) The lattice energy of CaO( s ) is –3460 kJ/mol; the lattice energy of K 2 O is –2240 kJ/mol. Account for the difference.
(c) Given these ionization values, explain the difference between Ca and K with regard to their first and second ionization energies.
| Element | First Ionization Energy (kJ/mol) | Second Ionization Energy (kJ/mol) |
|---|---|---|
| K | 419 | 3050 |
| Ca | 590 | 1140 |
(d) The first ionization energy of Mg is 738 kJ/mol and that of Al is 578 kJ/mol. Account for this difference.
The lattice energy of LiF is 1023 kJ/mol, and the Li–F distance is 200.8 pm. NaF crystallizes in the same structure as LiF but with a Na–F distance of 231 pm. Which of the following values most closely approximates the lattice energy of NaF: 510, 890, 1023, 1175, or 4090 kJ/mol? Explain your choice.
For which of the following substances is the least energy required to convert one mole of the solid into separate ions?
(a) MgO
(b) SrO
(c) KF
(d) CsF
(e) MgF 2
The reaction of a metal, M, with a halogen, X 2 , proceeds by an exothermic reaction as indicated by this equation: For each of the following, indicate which option will make the reaction more exothermic. Explain your answers.
(a) a large radius vs. a small radius for M +2
(b) a high ionization energy vs. a low ionization energy for M
(c) an increasing bond energy for the halogen
(d) a decreasing electron affinity for the halogen
(e) an increasing size of the anion formed by the halogen
The lattice energy of LiF is 1023 kJ/mol, and the Li–F distance is 201 pm. MgO crystallizes in the same structure as LiF but with a Mg–O distance of 205 pm. Which of the following values most closely approximates the lattice energy of MgO: 256 kJ/mol, 512 kJ/mol, 1023 kJ/mol, 2046 kJ/mol, or 4008 kJ/mol? Explain your choice.
Which compound in each of the following pairs has the larger lattice energy? Note: Mg 2+ and Li + have similar radii; O 2– and F – have similar radii. Explain your choices.
(a) MgO or MgSe
(b) LiF or MgO
(c) Li 2 O or LiCl
(d) Li 2 Se or MgO
Which compound in each of the following pairs has the larger lattice energy? Note: Ba 2+ and
K + have similar radii; S 2– and Cl – have similar radii. Explain your choices.
(a) K 2 O or Na 2 O
(b) K 2 S or BaS
(c) KCl or BaS
(d) BaS or BaCl 2
Which of the following compounds requires the most energy to convert one mole of the solid into separate ions?
(a) MgO
(b) SrO
(c) KF
(d) CsF
(e) MgF 2
Which of the following compounds requires the most energy to convert one mole of the solid into separate ions?
(a) K 2 S
(b) K 2 O
(c) CaS
(d) Cs 2 S
(e) CaO
The lattice energy of KF is 794 kJ/mol, and the interionic distance is 269 pm. The Na–F
distance in NaF, which has the same structure as KF, is 231 pm. Which of the following values is the closest approximation of the lattice energy of NaF: 682 kJ/mol, 794 kJ/mol, 924 kJ/mol, 1588 kJ/mol, or 3175 kJ/mol? Explain your answer.
Footnotes
- 4 This question is taken from the Chemistry Advanced Placement Examination and is used with the permission of the Educational Testing Service. | 6,718 | common-pile/libretexts_filtered | https://chem.libretexts.org/Bookshelves/General_Chemistry/Chemistry_-_Atoms_First_2e_(OpenStax)/09%3A_Thermochemistry/9.09%3A_Exercises | libretexts | libretexts-0000.json.gz:3706 | https://chem.libretexts.org/Bookshelves/General_Chemistry/Chemistry_-_Atoms_First_2e_(OpenStax)/09%3A_Thermochemistry/9.09%3A_Exercises |
F91XofQIGwuwHcS8 | Introduction to Electricity, Magnetism, and Circuits | 2 Gauss’s Law
Chapter Outline
Flux is a general and broadly applicable concept in physics. However, in this chapter, we concentrate on the flux of the electric field. This allows us to introduce Gauss’s law, which is particularly useful for finding the electric fields of charge distributions exhibiting spatial symmetry. The main topics discussed here are
- Electric flux. We define electric flux for both open and closed surfaces.
- Gauss’s law. We derive Gauss’s law for an arbitrary charge distribution and examine the role of electric flux in Gauss’s law.
- Calculating electric fields with Gauss’s law. The main focus of this chapter is to explain how to use Gauss’s law to find the electric fields of spatially symmetrical charge distributions. We discuss the importance of choosing a Gaussian surface and provide examples involving the applications of Gauss’s law.
- Electric fields in conductors. Gauss’s law provides useful insight into the absence of electric fields in conducting materials.
So far, we have found that the electrostatic field begins and ends at point charges and that the field of a point charge varies inversely with the square of the distance from that charge. These characteristics of the electrostatic field lead to an important mathematical relationship known as Gauss’s law. This law is named in honor of the extraordinary German mathematician and scientist Karl Friedrich Gauss (Figure 2.0.2). Gauss’s law gives us an elegantly simple way of finding the electric field, and, as you will see, it can be much easier to use than the integration method described in the previous chapter. However, there is a catch—Gauss’s law has a limitation in that, while always true, it can be readily applied only for charge distributions with certain symmetries.
(Figure 2.0.2)
Candela Citations
- Download for free at<EMAIL_ADDRESS>Retrieved from<EMAIL_ADDRESS>License: CC BY: Attribution | 390 | common-pile/pressbooks_filtered | https://openpress.usask.ca/physics155/chapter/2-gausss-law/ | pressbooks | pressbooks-0000.json.gz:65176 | https://openpress.usask.ca/physics155/chapter/2-gausss-law/ |
SntoPwinxtBj4tNe | Proactive Thinker - Volume 1: Communication | Apply for the Communication Badge
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oZ19yUmNQU_MA9EP | College Physics | Chapter 11 Fluid Statics
11.2 Density
Summary
- Define density.
- Calculate the mass of a reservoir from its density.
- Compare and contrast the densities of various substances.
Which weighs more, a ton of feathers or a ton of bricks? This old riddle plays with the distinction between mass and density. A ton is a ton, of course; but bricks have much greater density than feathers, and so we are tempted to think of them as heavier. (See Figure 1.)
Density, as you will see, is an important characteristic of substances. It is crucial, for example, in determining whether an object sinks or floats in a fluid. Density is the mass per unit volume of a substance or object. In equation form, density is defined as
where the Greek letter [latex]{\rho}[/latex] (rho) is the symbol for density, [latex]{m}[/latex] is the mass, and [latex]{V}[/latex] is the volume occupied by the substance.
DENSITY
Density is mass per unit volume.
where [latex]{\rho}[/latex] is the symbol for density, [latex]{m}[/latex] is the mass, and [latex]{V}[/latex] is the volume occupied by the substance.
In the riddle regarding the feathers and bricks, the masses are the same, but the volume occupied by the feathers is much greater, since their density is much lower. The SI unit of density is [latex]{\text{kg/m}^3},[/latex] representative values are given in Table 1. The metric system was originally devised so that water would have a density of [latex]{1 \text{g/cm}^3},[/latex] equivalent to [latex]{(10^3\text{ kg/m}^3}.[/latex] Thus the basic mass unit, the kilogram, was first devised to be the mass of 1000 mL of water, which has a volume of 1000 cm3.
| Substance | ρ(103 kg/m3 or g/mL) | Substance | ρ(103 kg/m3 or g/mL) | Substance | ρ(103 kg/m3 or g/mL) |
|---|---|---|---|---|---|
| Solids | Liquids | Gases | |||
| Aluminum | 2.7 | Water (4ºC) | 1.000 | Air | [latex]{1.29\times10^{-3}}[/latex] |
| Brass | 8.44 | Blood | 1.05 | Carbon dioxide | [latex]{1.98\times10^{-3}}[/latex] |
| Copper (average) | 8.8 | Sea water | 1.025 | Carbon monoxide | [latex]{1.25\times10^{-3}}[/latex] |
| Gold | 19.32 | Mercury | 13.6 | Hydrogen | [latex]{0.090\times10^{-3}}[/latex] |
| Iron or steel | 7.8 | Ethyl alcohol | 0.79 | Helium | [latex]{0.18\times10^{-3}}[/latex] |
| Lead | 11.3 | Petrol | 0.68 | Methane | [latex]{0.72\times10^{-3}}[/latex] |
| Polystyrene | 0.10 | Glycerin | 1.26 | Nitrogen | [latex]{1.25\times10^{-3}}[/latex] |
| Tungsten | 19.30 | Olive oil | 0.92 | Nitrous oxide | [latex]{1.98\times10^{-3}}[/latex] |
| Uranium | 18.70 | Oxygen | [latex]{1.43\times10^{-3}}[/latex] | ||
| Concrete | 2.30–3.0 | Steam 100º C | [latex]{0.60\times10^{-3}}[/latex] | ||
| Cork | 0.24 | ||||
| Glass, common (average) | 2.6 | ||||
| Granite | 2.7 | ||||
| Earth’s crust | 3.3 | ||||
| Wood | 0.3–0.9 | ||||
| Ice (0°C) | 0.917 | ||||
| Bone | 1.7–2.0 | ||||
| Table 1. Densities of Various Substances |
As you can see by examining Table 1, the density of an object may help identify its composition. The density of gold, for example, is about 2.5 times the density of iron, which is about 2.5 times the density of aluminum. Density also reveals something about the phase of the matter and its substructure. Notice that the densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. The densities of gases are much less than those of liquids and solids, because the atoms in gases are separated by large amounts of empty space.
TAKE-HOME EXPERIMENT: SUGAR AND SALT
A pile of sugar and a pile of salt look pretty similar, but which weighs more? If the volumes of both piles are the same, any difference in mass is due to their different densities (including the air space between crystals). Which do you think has the greater density? What values did you find? What method did you use to determine these values?
Example 1: Calculating the Mass of a Reservoir From Its Volume
A reservoir has a surface area of [latex]{50.0\text{ km}^2}[/latex] and an average depth of 40.0 m. What mass of water is held behind the dam? (See Figure 2 for a view of a large reservoir—the Three Gorges Dam site on the Yangtze River in central China.)
Strategy
We can calculate the volume [latex]{V}[/latex] of the reservoir from its dimensions, and find the density of water [latex]{\rho}[/latex] in Table 1. Then the mass [latex]{m}[/latex] can be found from the definition of density
Solution
Solving equation [latex]{\rho=m/V}[/latex] for [latex]{m}[/latex] gives [latex]{m=\rho{V}}.[/latex]
The volume [latex]{V}[/latex] of the reservoir is its surface area [latex]{A}[/latex] times its average depth [latex]{h}:[/latex]
The density of water [latex]{\rho}[/latex] from Table 1 is [latex]{1.000\times10^3\text{ kg/m}^3}.[/latex] Substituting [latex]{V}[/latex] and [latex]{\rho}[/latex] into the expression for mass gives
Discussion
A large reservoir contains a very large mass of water. In this example, the weight of the water in the reservoir is [latex]{mg=1.96\times10^{13}\text{ N}},[/latex] where [latex]{g}[/latex] is the acceleration due to the Earth’s gravity (about [latex]{9.80\text{ m/s}^2}[/latex] ). It is reasonable to ask whether the dam must supply a force equal to this tremendous weight. The answer is no. As we shall see in the following sections, the force the dam must supply can be much smaller than the weight of the water it holds back.
Section Summary
- Density is the mass per unit volume of a substance or object. In equation form, density is defined as
[latex]{\rho\:=}[/latex] [latex]{\frac{m}{V}}.[/latex]
- The SI unit of density is [latex]{\text{kg/m}^3}.[/latex]
Conceptual Questions
1: Approximately how does the density of air vary with altitude?
2: Give an example in which density is used to identify the substance composing an object. Would information in addition to average density be needed to identify the substances in an object composed of more than one material?
3: Figure 3 shows a glass of ice water filled to the brim. Will the water overflow when the ice melts? Explain your answer.
Problems & Exercises
1: Gold is sold by the troy ounce (31.103 g). What is the volume of 1 troy ounce of pure gold?
2: Mercury is commonly supplied in flasks containing 34.5 kg (about 76 lb). What is the volume in liters of this much mercury?
3: (a) What is the mass of a deep breath of air having a volume of 2.00 L? (b) Discuss the effect taking such a breath has on your body’s volume and density.
4: A straightforward method of finding the density of an object is to measure its mass and then measure its volume by submerging it in a graduated cylinder. What is the density of a 240-g rock that displaces [latex]{89.0\text{ cm}^3}[/latex] of water? (Note that the accuracy and practical applications of this technique are more limited than a variety of others that are based on Archimedes’ principle.)
5: Suppose you have a coffee mug with a circular cross section and vertical sides (uniform radius). What is its inside radius if it holds 375 g of coffee when filled to a depth of 7.50 cm? Assume coffee has the same density as water.
6: (a) A rectangular gasoline tank can hold 50.0 kg of gasoline when full. What is the depth of the tank if it is 0.500-m wide by 0.900-m long? (b) Discuss whether this gas tank has a reasonable volume for a passenger car.
7: A trash compactor can reduce the volume of its contents to 0.350 their original value. Neglecting the mass of air expelled, by what factor is the density of the rubbish increased?
8: A 2.50-kg steel gasoline can holds 20.0 L of gasoline when full. What is the average density of the full gas can, taking into account the volume occupied by steel as well as by gasoline?
9: What is the density of 18.0-karat gold that is a mixture of 18 parts gold, 5 parts silver, and 1 part copper? (These values are parts by mass, not volume.) Assume that this is a simple mixture having an average density equal to the weighted densities of its constituents.
10: There is relatively little empty space between atoms in solids and liquids, so that the average density of an atom is about the same as matter on a macroscopic scale—approximately [latex]{10^3\text{ kg/m}^3}.[/latex] The nucleus of an atom has a radius about [latex]{10^{-5}}[/latex] that of the atom and contains nearly all the mass of the entire atom. (a) What is the approximate density of a nucleus? (b) One remnant of a supernova, called a neutron star, can have the density of a nucleus. What would be the radius of a neutron star with a mass 10 times that of our Sun (the radius of the Sun is [latex]{7\times10^8\text{ m}}[/latex] )?
Glossary
- density
- the mass per unit volume of a substance or object
Solutions
Problems & Exercises
1:
[latex]{1.610\text{ cm}^3}[/latex]
3:
(a) 2.58 g
(b) The volume of your body increases by the volume of air you inhale. The average density of your body decreases when you take a deep breath, because the density of air is substantially smaller than the average density of the body before you took the deep breath.
4:
[latex]{2.70\text{ g/cm}^3}[/latex]
6:
(a) 0.163 m
(b) Equivalent to 19.4 gallons, which is reasonable
8:
[latex]{7.9\times10^2\text{ kg/m}^3}[/latex]
9:
[latex]{15.6\text{ g/cm}^3}[/latex]
10:
(a) [latex]{10^{18}\text{ kg/m}^3}[/latex]
(b) [latex]{2\times10^4\text{ m}}[/latex] | 2,017 | common-pile/pressbooks_filtered | https://pressbooks.online.ucf.edu/algphysics/chapter/density/ | pressbooks | pressbooks-0000.json.gz:40948 | https://pressbooks.online.ucf.edu/algphysics/chapter/density/ |
VQT6rPZWeLHugzGB | Early World Civilizations | 31 Ancient Egyptian Art
Learning Objective
- Examine the development of Egyptian Art under the Old Kingdom
Key Points
- Ancient Egyptian art includes painting, sculpture, architecture, and other forms of art, such as drawings on papyrus, created between 3000 BCE and 100 CE.
- Most of this art was highly stylized and symbolic. Much of the surviving forms come from tombs and monuments, and thus have a focus on life after death and preservation of knowledge.
- Symbolism meant order, shown through the pharaoh’s regalia, or through the use of certain colors.
- In Egyptian art, the size of a figure indicates its relative importance.
- Paintings were often done on stone, and portrayed pleasant scenes of the afterlife in tombs.
- Ancient Egyptians created both monumental and smaller sculptures, using the technique of sunk relief.
- Ka statues, which were meant to provide a resting place for the ka part of the soul, were often made of wood and placed in tombs.
- Faience was sintered-quartz ceramic with surface vitrification, used to create relatively cheap small objects in many colors. Glass was originally a luxury item but became more common, and was used to make small jars, for perfume and other liquids, to be placed in tombs. Carvings of vases, amulets, and images of deities and animals were made of steatite. Pottery was sometimes covered with enamel, particularly in the color blue.
- Papyrus was used for writing and painting, and and was used to record every aspect of Egyptian life.
- Architects carefully planned buildings, aligning them with astronomically significant events, such as solstices and equinoxes. They used mainly sun-baked mud brick, limestone, sandstone, and granite.
- The Amarna period (1353-1336 BCE) represents an interruption in ancient Egyptian art style, subjects were represented more realistically, and scenes included portrayals of affection among the royal family.
Terms
scarabs
Ancient Egyptian gem cut in the form of a scarab beetle.
Faience
Glazed ceramic ware.
ushabti
Ancient Egyptian funerary figure.
Ka
The supposed spiritual part of an individual human being or god that survived after death, and could reside in a statue of the person.
sunk relief
Sculptural technique in which the outlines of modeled forms are incised in a plane surface beyond which the forms do not project.
regalia
The emblems or insignia of royalty.
papyrus
A material prepared in ancient Egypt from the stem of a water plant, used in sheets for writing or painting on.
Ancient Egyptian art includes painting, sculpture, architecture, and other forms of art, such as drawings on papyrus, created between 3000 BCE and 100 AD. Most of this art was highly stylized and symbolic. Many of the surviving forms come from tombs and monuments, and thus have a focus on life after death and preservation of knowledge.
Symbolism
Symbolism in ancient Egyptian art conveyed a sense of order and the influence of natural elements. The regalia of the pharaoh symbolized his or her power to rule and maintain the order of the universe. Blue and gold indicated divinity because they were rare and were associated with precious materials, while black expressed the fertility of the Nile River.
Hierarchical Scale
In Egyptian art, the size of a figure indicates its relative importance. This meant gods or the pharaoh were usually bigger than other figures, followed by figures of high officials or the tomb owner; the smallest figures were servants, entertainers, animals, trees and architectural details.
Painting
Before painting a stone surface, it was whitewashed and sometimes covered with mud plaster. Pigments were made of mineral and able to stand up to strong sunlight with minimal fade. The binding medium is unknown; the paint was applied to dried plaster in the “fresco a secco” style. A varnish or resin was then applied as a protective coating, which, along with the dry climate of Egypt, protected the painting very well. The purpose of tomb paintings was to create a pleasant afterlife for the dead person, with themes such as journeying through the afterworld, or deities providing protection. The side view of the person or animal was generally shown, and paintings were often done in red, blue, green, gold, black and yellow.
Sculpture
Ancient Egyptians created both monumental and smaller sculptures, using the technique of sunk relief. In this technique, the image is made by cutting the relief sculpture into a flat surface, set within a sunken area shaped around the image. In strong sunlight, this technique is very visible, emphasizing the outlines and forms by shadow. Figures are shown with the torso facing front, the head in side view, and the legs parted, with males sometimes darker than females. Large statues of deities (other than the pharaoh) were not common, although deities were often shown in paintings and reliefs.
Colossal sculpture on the scale of the Great Sphinx of Giza was not repeated, but smaller sphinxes and animals were found in temple complexes. The most sacred cult image of a temple’s god was supposedly held in the naos in small boats, carved out of precious metal, but none have survived.
Ka statues, which were meant to provide a resting place for the ka part of the soul, were present in tombs as of Dynasty IV (2680-2565 BCE). These were often made of wood, and were called reserve heads, which were plain, hairless and naturalistic. Early tombs had small models of slaves, animals, buildings, and objects to provide life for the deceased in the afterworld. Later, ushabti figures were present as funerary figures to act as servants for the deceased, should he or she be called upon to do manual labor in the afterlife.
Many small carved objects have been discovered, from toys to utensils, and alabaster was used for the more expensive objects. In creating any statuary, strict conventions, accompanied by a rating system, were followed. This resulted in a rather timeless quality, as few changes were instituted over thousands of years.
Faience, Pottery, and Glass
Faience was sintered-quartz ceramic with surface vitrification used to create relatively cheap, small objects in many colors, but most commonly blue-green. It was often used for jewelry, scarabs, and figurines. Glass was originally a luxury item, but became more common, and was to used to make small jars, of perfume and other liquids, to be placed in tombs. Carvings of vases, amulets, and images of deities and animals were made of steatite. Pottery was sometimes covered with enamel, particularly in the color blue. In tombs, pottery was used to represent organs of the body removed during embalming, or to create cones, about ten inches tall, engraved with legends of the deceased.
Papyrus
Papyrus is very delicate and was used for writing and painting; it has only survived for long periods when buried in tombs. Every aspect of Egyptian life is found recorded on papyrus, from literary to administrative documents.
Architecture
Architects carefully planned buildings, aligning them with astronomically significant events, such as solstices and equinoxes, and used mainly sun-baked mud brick, limestone, sandstone, and granite. Stone was reserved for tombs and temples, while other buildings, such as palaces and fortresses, were made of bricks. Houses were made of mud from the Nile River that hardened in the sun. Many of these houses were destroyed in flooding or dismantled; examples of preserved structures include the village Deir al-Madinah and the fortress at Buhen.
The Giza Necropolis, built in the Fourth Dynasty, includes the Pyramid of Khufu (also known as the Great Pyramid or the Pyramid of Cheops), the Pyramid of Khafre, and the Pyramid of Menkaure, along with smaller “queen” pyramids and the Great Sphinx.
The Temple of Karnak was first built in the 16th century BCE. About 30 pharaohs contributed to the buildings, creating an extremely large and diverse complex. It includes the Precincts of Amon-Re, Montu and Mut, and the Temple of Amehotep IV (dismantled).
The Luxor Temple was constructed in the 14th century BCE by Amenhotep III in the ancient city of Thebes, now Luxor, with a major expansion by Ramesses II in the 13th century BCE. It includes the 79-foot high First Pylon, friezes, statues, and columns.
The Amarna Period (1353-1336 BCE)
During this period, which represents an interruption in ancient Egyptian art style, subjects were represented more realistically, and scenes included portrayals of affection among the royal family. There was a sense of movement in the images, with overlapping figures and large crowds. The style reflects Akhenaten’s move to monotheism, but it disappeared after his death. | 1,833 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/herkimerworldcivilization/chapter/ancient-egyptian-art/ | pressbooks | pressbooks-0000.json.gz:77377 | https://library.achievingthedream.org/herkimerworldcivilization/chapter/ancient-egyptian-art/ |
SfpY3dodU_8-Ts7_ | Estimating the cost of buildings; a systematic treatise on factors of costs and superintendence, with important chapters on plan reading, estimating the cost of building alterations, and on system in the execution of building contracts, by Arthur W. Joslin. | PREFACE TO FIRST EDITION
All of the matter contained in this volume appeared in substantially its present form in Carpentry and Building during the three years just passed. At the time of its writing I had no idea of its appearing in book form, but the articles were so well received that I have listened to the publishers of Carpent ry and Building [Building Age], and numerous acquaintances among builders and architects, and have slightly revised Jlie various papers for publication as a book under the general head of "Estimating the Cost of Buildings." Unfortunately, I have been obliged to undertake this revision at a time when I have been very busy in the conduct of our business. Had this not been the case I should have liked to have enlarged upon a number of the subjects treated, and may do so at some future time.
This volume is dedicated to my wife, whose loving presence in my home has made it possible for me to find pleasure there and the time to undertake such matters as this.
At the time of writing the first edition of this book I started out with the assumption that its circulation would be almost wholly among those who understood "plan reading." It has since developed that there is a demand for the book in evening classes in Industrial, Trade, Y. M. C. A. and similar schools where the students have little er no knowledge of plan reading and must of necessity acquire such knowledge before taking up the study of estimating from plans. I am therefore starting the Second Edition with chapters on this subject and have endeavored to treat it in language so simple that it will be readily understood by all. Suitable illustrations accompany these chapters, and it is hoped by both Publishers and Author that a much more useful book is being offered in this edition.
Definition of a Plan and General Explanations
A plan is a set of ' ' conventional ' ' signs usually drawn to scale, to illustrate the design of the structure that is to be built. A properly drawn plan, correctly read or understood, conveys a perfect mental picture of the completed work.
Scale of Drawings
The ratio of the plan to the work is as the scale of the plan to 12 inches. Thus on a ^-inch scale plan every part that can be measured is 1/96 of the intended length, width, height or thickness, for there are 96 one-eighth inches in 12 inches. Likewise a J-inch scale plan shows everything reduced 1/48 from the intended size or dimension. A ^-inch scale shows things reduced to 1/24 actual size. A J-inch scale to 1/16 actual size. A IJ-inch scale to J actual size. A 3-inch scale to J actual size. A 6-inch scale to 4 actual size. Drawings made the actual size of the parts are termed * * full size details. ' ' Drawings made to J-inch scale or larger, up to but not including full size, are termed "scale details."
Most building plans are drawn J-inch or |-inch scale. This means that each J-inch or ^-inch, as the case may be, on the plan, represents one foot in the structure. Therefore a floor plan that measured 10 in. on one of its sides, if drawn to the scale of J-inch, would mean 40 ft. in the actual building, as there are 40 onequarter inches in 10 inches.
If the plan was drawn to the scale of |-inch and measured 10 in. on one of its sides, it would mean 80 ft. in the actual building, as there are 80 one-eighth inches in 10 inches.
Full Size Drawings
Details drawn to large scale or full size are made to show essential particulars that it is impossible to show on J-inch or J-inch scale plans. On all drawings where figures are supplied they are given in numerals followed by the customary signs for feet and inches; thus a dash to the right of and just above the figure signifies feet, two dashes similarly placed signifies inches ; six feet and nine inches would be written on a plan as follows 6'-9", or twenty-one feet and three- f ourths . of an inch, thus 23/-0}". The different plans usually furnished for a building are floor plans, elevations, sections and more or less scale details. Basement and cellar plans come under the head of floor plans.
Elevations are plans of the sides of buildings, and they show doors, windows, pitch of roofs, etc., which can not be fully shown or made clear on a floor plan. Thus, a floor plan can, by the conventional sign, show the location of a window in a wall, but it can not show its height, width of casings, thickness of stool, whether having backhand molding or not, manner of cutting up sash into lights of glass, etc. All of these things must be determined from the elevations, and in particular work these J-inch or J-inch scale elevations are further supplemented by large scale or full size elevations and sections.
A sectional drawing is a representation of the construction of a building, or part of same, showing of what members or parts the building, or part of same, are made up.
" Cross hatching" is a series of diagonal lines filling in the entire space between two or more lines defining the outline of any member or part of the building cut through and brought into view by a sectional drawing. Where members
building brought into view by a sectional drawing, but not cut through, are elevations. Thus a drawing taken on an imaginary line through a building would be in part a sectional, and in part an interior elevation, drawing.
Public improvements sometimes require the literal cutting in two of a building and the destruction of one part. The part left standing, showing the ends of joists, walls, partitions, etc., and the walls of various rooms with doors, base, trim, mantels, etc., all in plain view, is a living example of a sectional drawing.
sectional drawing.
A cellar, basement or floor plan is the view of a building if it were sawed in two horizontally somewhere about half way between the floor and the ceiling, and the upper part removed.
and this will be explained later.
Plans are usually accompanied by specifications, which in great measure describe at length the kind and quality of the materials to be used in carrying out the work, and the methods and order of performing it.
Assuming that the reader -knows very little about plans, the first thing he should do is to read the specifications carefully. This will help him to determine the meaning of some of the lines or signs on the plan.
You probably found in reading the specifications that all walls, piers, chimneys, etc., were to have footings. Now, as footings are below the cellar floor and cannot be seen on the plan, and as you probably know without being told that they extend beyond the parts over them, you at once identify the irregular dotted line "A" as the outline of the footing for the chimney and the
io ESTIMATING THE COST OF BUILDINGS
two piers built in conjunction therewith. If you know so little about a plan as to be in doubt as to how a chimney is shown, the fact that the inner rectangle is marked "Ash Pit" ought to help to identify the pair of parallel lines inclosing it as a chimney, shown in plan.
Details of Chimney
Having made up your mind it probably is a chimney that is shown, the parallel lines, which will be found by using a scale rule, are 4" apart, it is at once determined that it is the brick wall which makes the chimney. Now observe the smaller rectangle inclosed in double lines (B) about one inch apart by scale and above the ash pit as you look at the plan. It is known that a chimney has a flue or flues, and you should readily identify this as a flue having a flue lining. The double lines, one inch apart by scale, with the four inch wall around it, should convince you beyond a doubt that it is a chimney that is shown. If further evidence is necessary there is the circle marked "Heater," and the dotted lines from heater to flue, meaning of course the smoke pipe leading as they do from the heater to the flue. The figures within the flue "8/12" signify that it is an 8" x 12" flue, which you know to be one of the sizes in general use.
The method of noting size on the plan (8/12) is a sort of short hand, as there is not room to write out the size in full with "inch signs" added to numerals (8" x 12").
The cleanout door for the ash pit is indicated by a line on the outside wall of the chimney. It is marked "Door," is 15 in. in length by scale, and its size is probably given in the specifications.
If, using a carpenter's rule, each one- fourth (%") of an inch means one foot (l'-0") in the actual work, it naturally follows that one-sixteenth of an inch represents three inches ; one-eighth of an inch six inches, and three-sixteenths of an inch nine inches in actual work. Such dimensions as 1", 2", 4", 5", 7", 8", 10", 11" are determined by "eye" when using the carpenter's rule. If a scale rule is used there are graduations reading to each inch.
Having thoroughly analyzed the small portion of a plan shown in Fig. 1, we will now analyze a complete set of plans for a small dwelling. The set of plans are shown in the following diagrams, of which
All of these drawings are made to scale of J" to 1'. Each drawing is supplemented by numerous notes and figures, also by detached sections and elevations from J" to f " scale.
Analysis of the Foundation and Cellar Plan
Probably the first thing observed upon looking at the cellar plan, Fig. 2, is that two parallel lines form a somewhat irregular rectangle. The outer line represents the outside of the founda-
tion upon which the house is to be erected. The inner line, which is figured in several places as being 16" from the outer line (see A-B), represents the inside line of foundation. The figures 16" between these lines at several places call attention to the fact that the foundation wall is 16" thick.
Notice that wherever this dimension is put on the plan between lines representing the outside and inside lines of the foundation, there are small arrows, thus: -* 16" -e- These arrow points are called "witness marks," and they convey the information that
the 16" is from one of these marks to the other. Ordinarily the shaft of the arrow would be towards the figures, as in the case of the dimension 34'-0" at the top of the plan "C," which, by the location of the witness marks at the right and left of it, shows that these figures represent the length of the building on that side.
The reason for reversing the arrows in the case of the 16" dimension is that the two parallel lines are so near together that there is not room to continue the shaft lines towards each other and leave room for the figures. The usual custom in regard to the "extended arrows," or dimension lines, put on plans is to make them of red or diluted black ink, so that when the blue print is made they come out as a faint line. While faint they are easily distinguishable, but not heavy enough to be confused with the full prominent lines of the plan.
The witness marks or arrow heads are put on drawings in black ink so that when blue-printed they will stand out prominently and call particular attention to the points between which the dimension is taken. In laying out work from a plan figures should always be followed in preference to dimensions obtained by scaling the plan. In using the figures particular care should be taken to note to which lines or points the witness marks refer.
Where 'intermediate measurements, as well as over all, are given, as in the dimension next below the 34'-0" referred to, the said intermediate figures should be checked to see that their total agrees with the "over all" figure. Thus the figures (on the line of figures under 34' -0") ll'-O" from outside of wall to center of mullion window, 16'-6" from center of mullion window to center of single window, and 6'-6" from center of single window to outside wall are found to total 34'-0".
Go down further on the plan to the line of figures D, and we find the figures 19'-0", witnessed from outside of wall to a line continued from the center of a column, followed by the figures 15'-0", witnessed from center of column to outside of the opposite wall. We find that the dimensions 19'-0" and 15'-0" added also give us 34'-0". As the outermost witness marks in the case of the last two of these lines of dimensions are from the same lines on the plan as those of the line C, each should total 34'-0", as in C.
Failure to do so is evidence that there is an error somewhere in the figuring. By comparing plans over and under the one in question, checking their figures, and by using the scale rule where figures are manifestly incorrect, a correction can usually be made by the person attempting to lay out the work from the plans. Failing to discover the error by the above method the matter should be referred to the architect or his representative who
addition of unnecessary lines
makes the plan complicated, and it is made plain in other places that footings are required, the plan is just as clear as though they were shown.
Now look at Fig. 3, which is
a section through the foundation wall. The thickness of wall at the top and bottom, respectively 16" and 2'-0", is shown here ; also the depth of the cellar from under side of first floor construction when plastered to the top of concrete (7'-6") ; the shape and location of footing; size of the sill and its location on the wall ; and several other points of construction. You have probably noticed that the vertical lines representing the wall are not continuous as at A. The lines are "broken," as it is called to compress the drawing into a smaller space. If you scale the distance figured 7'-6" you will find that it falls short of this figure. The height of wall as shown in this section being broken twice, once above and once below the line B, which denotes the outside grade, establishes the fact that the amount of Avail above and below the grade is variable, as is
elevations.
Also notice that this section shows a 4" x 6" sill laid flatways on the wall and far enough from the outer edge of the wall, so that when it is studded up above the sill and outside boards put on, the outside line of boarding is flush with the outside of the foundation.
Now to refer back to Fig. 2 in the lower right-hand corner, we find the note, " All measurements are Outside of Frame." If you look carefully at the dimension lines you will see that lines extending from the corners to which dimensions are figured, are by scale, about 1" short of the full line representing the outside line of the foundation (see F).
A glance at Fig. 2 shows that the floor joist C is sized onto the sill about 1", that there is an under and upper floor, denoted by the two lines drawn parallel to the line representing the upper edge of the joists; and that the ceiling of the cellar is sheathed or plastered, as denoted by the line below and parallel with the line representing the bottom edge of the joist. The specifications probably confirm the matter of the two floors and state whether ceiling is sheathed or plastered. The plans have frequently to be considered with each other and with the specifications, and then coupled with some little knowledge of construction, in order to have them convey to the person attempting to read them what the arohitect intends to have built.
In the upper right-hand corner of Fig. 2, and within the pair of parallel lines representing the foundations, are two divisions plainly marked "Range and Heater Coal." The lines which bound and form the partitions are about 1" apart by scale, indicating that the partition G would be composed of 1" or $•" boards, which should be nailed to the studs H, about 30" apart by scale. The door is at J, partly open to show the swing, and behind the door is the * ' Hopper. ' '
In the lower right-hand corner of Fig. 2 is another compartment, marked "Cold Closet," shown by lines similar to those denoting the coal bin, except that there are two parallel lines on each side of the studs, This, of course, means that the cold closet
partition is boarded on each side of the studs, and an examination of the door K shows that this is of double construction also. The lines inside of the cold room are to represent shelves, and as a plan could not show how many and there is no section given, the note "3 Sh's" (3 shelves) is added. Possibly the specifications would mention this, but whether they did or not, the note settles the question of how many shelves, and the drawing shows the width.
noted.
Fig. 4 is a typical column like those on the cellar plan Fig. 2 near W. C., and foot of stairs. The detail illustrates a side elevation of floor joist A ; section of girder B ; elevation of column C ; section of concrete floor D ; elevation of small block of cast concrete usually sold with columns E, and a section of the footing under the column F. For convenience in drawing, this column is shown "broken," but the figures give the correct dimension between floor and ceiling, and agree with the section shown in Fig. 3,
Outside of the lines representing the foundation on Fig. 2, to the right and left at the top, are the piers supporting the front and rear porches. The size of the piers is figured as well as drawn to scale, and the footings in all cases are shown dotted.
We have now examined in detail nearly everything shown on this cellar plan except the stairs indicated at M, which start straight with two steps, take a right angle turn with "winders" and continue up to the first floor. See bent arrow marked "up.'' The stairs are shown in full lines about halfway up, when they change to dotted lines. The upper part of these stairs can be seen on the First Floor Plan, where the arrow is noted "Down."
The height of the foundation out of the ground, the style of the cellar windows and other similar particulars are obtained by referring to the elevations which show all four sides of the building.
the same outline as the foundation and cellar plan shown in Fig, 2. Notice, however, that the two parallel lines are much nearer together than on the foundation plan. If you try a scale rule on
FIRST, SECOND AND ATTIC FLOOR PLANS 19
these lines you will find that they scale 6 in. apart. In an ordinary frame house or other structure the outside is assumed to be 6 in. through. This thickness is made up as follows : Studding, 4 in. ; outside boards, 1 in. ; plastering, 1 in. ; total, 6 in. To be accurate the studding is 3J in., the outside boards £ in., the plastering J in. The shingles, clapboards or other outside wall covering and the base inside are not taken into account in making -£ in. or smaller scale drawings. The draughtsman assumes that you know of the existence of these parts and that you will look to the elevations, large scale and full-size details and the specifications, for more particulars in regard to them. All interior partitions that are built of 4-in. studs are also assumed to be 6 in. and are so drawn. Partitions shown a little less than 6 in. by scale are of 2 in. x 3 in. studding, and if shown even thinner than those implying 3-in. studding, they may be assumed to be built of 2 x 3 or 2 x 4 set flatways.
Partitions marked E on the plan Fig. 5 are of 3-in. studding ; those marked F are of studs set the 2 in. way. The partition which divides the dining room from the living room and is figured 10 in. is for a large single sliding door. When the door is opened, it slides into a pocket, about 3 in. wide, made by the two partitions G.
Windows in general, on small scale drawings for frame buildings, are shown by two parallel lines between the lines representing the outside wall, the length of these lines being the scale width of the sash. A typical window is shown at H. Where windows are grouped they are shown as at J, representing a mullion window, and at K, representing a triple window. These same parallel lines between partition lines would represent a sash in a partition. To find the style, height, etc., of these windows shown in the outside wall, the elevations must be referred to.
Doors are shown by an opening in the parallel lines representing a wall or partition as at L. From these openings there are lines at an angle with a segment of a circle faintly shown. The line at an angle represents the door and the faint line shows which way it swings. Notice that each door is figured for size. Wood,. style and thickness or any other particulars must be obtained from other drawings and the specifications.
The door marked M represents a double swing door. Notice that the angular line is dotted, shows both sides of the partition, and that the segment of circle, showing swing of door, continues each way from the partition. At the outside doors (from reception hall to porch, and back hall to rear porch) you see a line about 2 in. by scale from the outer line of the two denoting the outside wall and running 5 in. or 6 in. by scale beyond the opening shown for the door. This shows the threshold and also implies a riser or difference in height between the levels of the floor in the building and on the porch. If you will step outside of your own front door and look at the threshold of it, I think you will see at once the conditions just explained and the logic of the method of showing them on the drawing.
and equipment of various kinds.
Next examine the stairs going up from the reception hall. The first riser N is carried around at right angles until it stops against the partition that follows down under the second run of stairs X, the corner being a quarter circle. This is called a block step. The newel 0 starts on this block step, the next riser (2) is also a block step, and ends in a small quarter circle against the newel. Next are the risers Nos. 3, 4, 5, 6, a platform, a right angle turn and risers 7, 8, 9, where the stairs have reached a height somewhat above halfway to the second floor, and a closet is put in under them.
The balance of these stairs will be seen at A on the second floor plan, Fig. 6, where the riser numbers are picked up at No. 9, and continued to No. 15. Notice that the arrow at the start of these stairs on Fig. 5 says ''Up 15 R." Now look at the stairs going up out of the kitchen where arrow says "Up 14 R." Here we find five risers up to the level of the platform of the front stairs. There is a door from the kitchen to these stairs, also a door at the top, on the platform, to cut them off from the kitchen and the front stairs. This part flight to the platform is called a "box flight/' as it is between two walls; consequently it does not require posts, rails and balusters, but has a wall rail on the right as you go up, shown by the parallel lines close together. The lines representing the rail turn with a quarter circle at right angles
at each end, and is fastened there to the partition.
As we have six risers from the reception hall, and five risers from the kitchen, the fact is established that the height of each riser in the box flight from the kitchen is increased enough to
cover the distance from the first floor to the platform. An arrangement of stairs like this is called a "combination stair." Besides the box flight from kitchen to the platform, there is the flight of stairs leading to the cellar (A). Here the arrow says "Down." This is between partitions and is a box flight at the start, but as you go down into the cellar it becomes an open flight.
The partition between these stairs and the front stairs at P, would have to stop even with the under side of the stringer of the upper run of the front stairs (risers 7, 8, 9, etc.) in order to make "head room" for the cellar flight, At the point where this partition occurs we have gone up 7 risers and down 5 risers from the first floor. As the average riser is about 8 in. high we have in the 12 risers about 96 in. or 8 ft. Out of this must come the depth of the stringer under risers 7, 8, 9, etc. As this would be only 5 in. or 6 in. you readily see that there is ample head room for the cellar flight. There is no way that this stopping of the partition under the upper run can be shown on the floor plans, but when the arrangement of stairs is studied the fact must be evident.
The chimney in the corner of the living room is clearly indicated. The 8-in. x 12-in. flue shown on the cellar plan Fig. 2 is in evidence. As the corner of the chimney having this flue comes into the kitchen the inference may be drawn that this flue also serves for the kitchen range, which is shown in the corner of the kitchen Q. The kitchen boiler marked B is in a niche back of the range.
Notice that the part of the chimney showing in the kitchen and boiler niche has no line enclosing it as in the dining room at F. This shows that this much of the chimney is exposed and requires the brickwork to be laid up neatly and possibly of better brick than the rest of the chimney. This is one of the points that is undoubtedly settled by the specifications.
The Bookcases and Fireplace
The fireplace is fully shown and carefully figured even to the face brick lining, hearth, dump to ash pit under, etc. Notes on the plan at this point show that a seat and bookcases are worked in around the chimney corner. The large scale or full-size drawings do not come as a rule until after a contract with the builders is made and it is about time to build in the special parts; in consequence the estimator has to determine the requirements from the small scale drawings, the specifications and his experience with work in general and his consultations with the architect.
reference to the elevation will show which of the various lines represent steps, posts, rails, etc. Large scale details are shown of the front porch and living room bay, and these will be taken up later and references made to the first floor plan.
The Second Floor Plan
We will now study the second floor plan, Fig. 6, but at much less length than was devoted to the first floor plan. Here we see the same outline as the first floor, except the front of the building, where the dotted lines B show the outline of the first floor. As the parallel lines representing the front wall of the building show, the second floor overhangs to the face of the two projections on the front wall of the first floor, and the part of the second story front wall over the porch has a still further overhang or projection in the form of a square bay C. Everything in regard to partitions, doors and windows explained in connection with the first-floor plan applies to the second floor.
In the bath rooms a bowl, bath tub and water closet are shown. As each of these fixtures is noted, you cannot help locating them on this plan. The conventional methods of showing these fixtures never varies much from the way they are shown here, and, even if the fixtures were not noted, no difficulty should be experienced in identifying them.
The Chimney
Notice the chimney D. Here we have a plain rectangularshaped affair with two 8 x 12 flues. If you look at the drawing carefully you will see that the two flues are side by side, having no brick withe (partition) between them. The flue No. 1 is the same one shown in the plan of the chimney on both the foundation and first-floor plans. The other flue, No. 2, is for the fireplace. As this starts midway between the first and second floors, drawing the flue on the first floor over all the lines showing the fireplace would only serve to complicate the first-floor plan, and no attempt is made to show it there.
The part of the plan marked E is the front porch roof. The roof and gutter lines are shown, and the fact that it is a shingle roof is noted. The dotted line shows the outline of the frieze of
While discussing the foundation and cellar plan attention was called to the fact that all dimensions were to "the outside of frame." This note applies throughout all the plans. Take the dimension 34 ft. referred to on the foundation plan ; compare the same side of the first and second-floor plans and you will see that it is the same on both. You will also see that the 11-ft. dimension at the left, and 6-ft. 6-in. dimension at the right, which are to the center of the windows, or mull ion windows, also applies to all three plans. An examination of the elevations of this side of the
house will show by the lines drawn over the plan, running through the center of the windows, and groups of windows, that they center over each other and at the same figured distance from the corners of the building called for by the floor plans.
that the line representing the inside line of the wall is discontinued shortly after it passes the partitions that intersect it as at C, but that the line denoting the outside of the wall is continued to the corner. This is to show that while the studding, boards, wall shingles, etc., continue to the outside corners, the plastering occurs only when the inside of the wall is in a room or finished part of the attic.
The balance of the outline of the house at attic floor level is shown by a dotted line D. The dot and dash lines E show the roof plan, those around the outline being the line of the outside of cornices and rakes, and the one through the center being the ridge of the roof.
Everything else necessary to know on this plan can readily be determined by applying the explanations given with the first and second floors and by reading the notes.
Drawings
We will next take up for consideration the various elevations, of which Fig. 8 represents the front, Fig. 9 the rear, Fig. 10 the left side and Fig. 11 the right side elevations. These are all drawn to ^-in. scale, but are here reproduced one-third that size or to a scale of %2 in- equals one foot. An elevation drawing of
the side of a building is one in which every part that can be seen, if you were standing directly in front of the center of a side of a building, and at sufficient distance so that all perspective effect was lost, was brought forward into a vertical plane and pictured as though it was a flat surface.
ELEVATIONS AND ROOFS
In drawings of this kind true heights, widths and other measurements may be obtained, whereas a perspective drawing like a photograph, cannot be measured in the ordinary way. Look at the upper part of Fig. 8 at A, where the front slope of the roof is shown. As far as this drawing goes it might be a vertical surface. Now look at the left side elevation in Fig. 10 and you will see that it is a sloping surface.
If you scale the vertical distance A on both Figs. 8 and 10 you will find that they are the same. As you look at this elevation (Fig. 8) your judgment must tell you that the surface A is the
main roof, the surface B the bay-window roof, and the surface C the porch roof. From this drawing you may scale the true vertical height of these roofs, but to get the pitch or slope of them you must refer to either one or the other of the side elevations which are at right angles to the front. Look at the side elevations, Figs. 10 and 11, where the roofs are marked B and C.
Thus from the elevation drawings you can obtain all information relative to door and window heights, widths, style, etc., size and slope of roofs, style of cornice, porches, balustrades and outside trim generally, so far as such parts may be intelligently shown at such a reduction from the full size. Conventional methods of drawing or notes also make clear the materials used for wall and roof coverings. When all of the above are taken with the floor plans and specifications, a true mental picture of the structure is produced, and all of the drawings may be read as figured, or
upon or carrying out the erection of the building.
To make perfectly clear to the estimator or builder the style and construction of cornices, porches, bay windows, etc., large scale drawings are given as follows : f -in. scale section and elevations of front porch, Fig. 12; f-in. scale section through living room bay, Fig. 13, and IJ-in. scale section through main cornice, Fig. 14. The J-in. scale typical section through wall and roof
LARGE SCALE DETAILS AND BLOCK PLAN
of house, from footings to roof (Fig. 15), provides an opportunity to show size of joists and rafters, and heights of stories properly figured. For purposes of publication these drawings are presented to a scale one-third of that mentioned.
There is also shown, at a scale of 40 ft. to the inch, a "block plan," as in Fig. 16. The main purpose of this plan is to show the location of the house on the lot. It should, and usually does, show many other things necessary to know and inconvenient to
put on the general plans. Among these things are the following : Dry wells and locations ; sewer, gas and water mains, their distances from the house and the direction in which connections of the above take to reach the house ; cesspools and locations ; walks. retaining walls, driveways and fences ; size and shape of lot ; points of the compass, etc.
them and their relation to each other. So much has been offered in explanation of the several floor plans, small sections and elevations that it would seem that further words would only confuse the reader. However, a few words in explanation of some of
Fig. 13 is a section through the living room bay and is also drawn f in. to 1 ft., but published one-half this size. It shows the bay as it would look if cut in two on the line D-D, Fig. 8, and
the left-hand piece was removed, so that you would see the construction from the main sill on the foundation up through to a point a foot or so above the second floor.
Everything revealed by this "autopsy," that is actually cut through, is cross-hatched, or in the case of large members like the sill and girt, shown in imitation of a large piece of end wood, the growth rings and checking being simulated. The joists and studding, the sides of which stand revealed, are drawn in imitation of a large piece of timber or plank as seen sideways, the side grain being simulated.
half this size.
Fig. 15 is a scale section through the house, from footing course to roof, making no attempt to show anything except story heights, joists and rafter sizes, height of rough window openings, etc.
Many architects and draughtsmen use colors and different types of cross-hatching to show the materials of which the various parts are constructed. For instance, red is used to show brick in plan or section, yellow to show wood, and blue to show stone, etc. While these different colors and the several types of cross-hatching are frequently used, custom varies as to their
necessity.
The proper reading or understanding of plans is a progressive study. As you grasp the meaning of one thing shown, the meaning of other parts adjacent, become apparent. As knowledge of actual construction and architecture is acquired, the meaning
of the lines becomes more and more evident, and while sufficient explanations have been given above to start the student on his way, he must be ever observant of things structural and architectural if progress is to be made.
Knowledge Required by the Estimator
No one should undertake to estimate quantities from plans until he has reached a point where a drawing is as easily read or comprehended as so much printed matter is read and understood by a person taking up a book or paper dealing with a subject with which he is familiar.
It is to be hoped that a careful study of the preceding chapters, and the drawings which accompany same, will have prepared the student to come up to the above requirements and thus enable him to follow the subject intelligently.
There have been a number of books written on this subject, but in the main they tell how many, brick there are to the foot in various thicknesses of walls, how much waste there is on lumber, how much work of various kinds a man ought to do in a day, and so on. Now all of this is very essential, but the problems that confront most beginners when a large plan is given them to estimate on are more like these : Where am I going to begin ? How am I going to know when I have taken off all the materials of a given kind? And how shall I go at it to know that I have omitted no important item?
Most men engaged in any of the various trades connected with the building business who get to positions where it becomes a part of their duty to " survey " quantities, and estimate costs on same, I assume are able to perform the ordinary operations of arithmetic, such as addition, subtraction, multiplication and division, both of simple numbers and of fractions or decimals. I shall also assume that they understand more or less of mensu-
planes and the contents of various shaped solids.
In the chapters dealing Avith "estimating" I shall not enter into the matter of "costs" any more than to try and show how you can work out for yourself the cost per unit of the various items going to make up a building. As the cost of the various commodities entering buildings, also the labor necessary to install them, are so variable in different parts of the country, my reasons for this must be plain.
I shall treat the question from the point of view of the man figuring the "general contract." In the natural order of things he has either been a journeyman mason or carpenter before circumstances placed him in the lists as superintendent or contractor.
No one man can know everything about all trades, and so it will be impossible for him to figure everything. Nevertheless, if he has had his eyes and ears open he should know enough to estimate at least two-thirds of everything entering a building. Such items as electric work, plumbing, heating and ventilating and a few others require to be figured by men having an intimate personal knowledge of these trades. It is very embarrassing, when called upon to submit a bid for a building, to have to chase all over town to get sub-bids to cover three- fourths of the job before being able to make up a figure. Your own judgment and ability should enable you to make a figure on the work with but little assistance from others.
It is an unwritten law in the building trades that if a subbidder has figured some portion of the work for you, and you have used his bid in making your figure, he should be awarded that part of the work in event of your success in obtaining the contract. This is only just and proper, as he has given of his time and brains to assist you in making a price for the work.
My experience has been that you can get closer bids for such parts of the work as you wish to sublet if the parties estimating know that you have actually got the work to let out.
I trust that the above remarks have prepared the reader to take up with me the actual study of the subject in hand. Please bear in mind that opinions vary and that none of us are perfect.
I am not claiming to know all that there is to know on this subject, but having for more than 14 years done enough figuring to keep about 150 men employed, on the average, and the firm's accounts showing credits on the profit side of the ledger, I feel that what I may have to say will be of help to many.
Method of Estimating
In general practice no two buildings which you are called upon to figure will be exactly alike; nevertheless, you can have a general system or method and vary it to suit individual cases. By having such a system and always following it as closely as circumstances will permit, you become more expert and eliminate the possibility of errors. Bear with me for stating some things that are obvious to the average reader, and remember that there probably will be, among those who follow this subject with me, men to whom very little is plain. It is in order to make things clear to them that I go into these seeming trifles.
When a plan and specification is handed to you and you are requested to make a bid for the work, the first thing to do before commencing to figure is to look the plan over for 15 or 20 minutes, or longer if necessary, until you have a sort of "mind picture" of the building. The next thing in order is to view the site. It is not safe to put in a figure on a job if you have not seen the site, unless it is in a locality with which you are entirely familiar. The circumstances of site may make a good deal of difference in your prices per unit for materials. For instance, the structure may be on a side hill, or removed from the traveled road; there may be no water near, or the site may be covered with trees ; or in the case of a town or city building you may be so hemmed in with buildings as to make the handling of materials very difficult. All of these things are going to affect your price and you should know them. I have often gone 100 miles to have a look at the site of some structure on which I was figuring, not staying at the site more than half an hour, but always coming back with enough extra information to feel amply paid for the time and expense.
Next read your specifications all through, not only those parts that you intend to figure yourself, but everything. You can conveniently use the time you are traveling to and from the site for doing this. You will now have an intelligent idea of what you are about to estimate upon.
Provide yourself with a suitable book for your estimates. I have found that the most convenient book for this purpose is one of the loose-leaf kind, with pages about 6x9 in., also having an index. Number your estimates, as for instance, No. 51; put down the title of the building, together with owner's and architect's names, the date, etc. ; and as your estimate will use up several pages, number the pages. You will find that keeping an index of your estimates under the owner's or architect's name, or both, will be valuable to you if you should want some time afterward to refer to them. With the loose-leaf book you can take out several sheets and take them with you to an architect's office, home of an evening, or anywhere else without carrying the book with you. When your book becomes full you can remove everything but your index, and by running tapes through the holes bind a hundred or so estimates and file away.
Now take the plans apart, and if you have space to do it, spread out your several elevations and sections, or better still, tack them up in front of your table. Leave all of your floor plans on the table, with the foundation or cellar plan on top, first floor next, and so on.
Now open your specifications at the first item, which will probably be "clearing the site." Having visited the site, you can now set a price on the work you will have to perform before you can begin your excavation. The cost of this item will be largely a matter of judgment. We will assume, for example, that it is a suburban site; perhaps there are 10 large trees to cut down and the stumps to remove, a lot of underbrush to be cut, and the limbs and brush from the trees to be burned up or otherwise disposed of. Then reason as follows: The average tree will require a day's time to cut down and lop off the limbs and brush ; to get out the stump it will take two men a day ; this makes 30 days ' time for the 10 trees. Now for the brush : After sizing it up you conclude that a couple of men can cut it all down in a day, and that it will take them another day to gather it up, together with the limbs of the trees, etc., and burn it up. Thus you have a total of 34 days' work, which, if done by laborers at $2 a day, would be $68, giving you the cost of this item.
Before starting the excavation you will put up "batters," and if the work is large you will probably require the services of an engineer and his helper for a day. A few minutes' study of the plan will tell you how many posts you have got to drive and how much lumber these and the boards for them will require. Picture yourself there with a carpenter or two and a laborer, and determine how long it will take to put up the batters and get the marks on them; then the cost of the lumber, plus the amount you have determined upon for labor, plus the cost of the engineer and his helper for a day, gives you the cost of this item.
Excavation and Ground Work
The common "unit of measure" used in estimating excavations is the cubic yard, or 27 cu. ft. Look up your sections and see how much larger than the size of the building your excavation will have to be on account of the projection of the footings. This determined, get the area of the building, allowing sufficiently all around for projection of footings, and consult your elevations for the natural grades and the depth of the cellar, taking the depth to the 'bottom of the concrete for the general cellar level, and put it down on the estimate sheet (Fig. 17, for example, sizes assumed). Now, if there is some deeper part, as, for instance, a boiler room, take this area by its depth below the former depth used. Now take your footings, which are probably below the depths just figured, taking the outline of the building first, then your cross walls, and pier and chimney footings next. Then if there are areas, bulkheads, etc., set down their dimensions. Continue thus through the entire excavation. Now I would advise that you do not proceed at once to carry out the result of these measurements, getting the number of yards and putting a price on them, but proceed to the next item, putting down the dimensions for it as I have done for excavation. There are several reasons for this: First, you want to get through with the plan as soon as possible, roll it up and have it out of the way. Second, you can take the estimate sheets with you in your pocket and figure up an item at your desk, at home of an evening, while on a railroad train, or anywhere, in fact, that you happen to have a few minutes, thus utilizing a lot of time that you usually let go to waste. Third, I find that without the plan in front of you to distract your attention, you can concentrate your thoughts upon the figuring much better, thus carrying out your results quickly and accurately. Fourth, by this method of taking off the quantities you can drop the work at any stage of the surveying of the plan or carrying out the results of the measurements and figuring the cost, by
finishing the item you are working on and take it up again later the same day, or a week from then, a glance at your estimate sheets showing you just where you left off.
with each item as we go along.
Now to get back to the item of excavation: By figuring out the dimensions set down under this heading you will find 32-, 503J cu. ft., which makes within a few feet of 1204 cu. yd., so
we set down the number of yards as 1204. In putting a price on this work you must consider how you are going to handle the job, whether with wheelbarrows or carts; the kind of soil, wet or dry, clay or gravel, etc. ; also, how far you have got to carry the excavated material to pile it up or dump it.
If ordinary digging piled up within 100 ft. or so from the cellar, it will cost you around 30 cents per yard, and if, as it often happens in the city, the excavated material has to be carted a couple of miles to a dump, the cost will be around $1.50 per yard. In this case I have assumed about the first conditions and set the price at 35 cents per yard, making the cost of this item $421.40.
Shoring and pumping is usually all a matter of judgment. You will have to analyze the work to be done the same as I have done on the ' ' clearing the site ' ' item, making up your mind how many days ' labor will probably go into pumping, and how much labor and stock it will require to do the shoring. On all such items as this, which are purely the result of analysis and judgment, it is better to reason out and put down the cost while the plan is right before you, and you have reached and are considering the item. As a rule this takes little time.
Piling
Perhaps the building is on piles, and if so there will be a piling plan showing the number and disposition of them. By starting at some corner of the building and going around the outline, taking next all cross walls running in one direction, then cross walls in the opposite direction, then angular cross walls, followed by the isolated bunches for piers, chimneys, etc., it resolves itself into a matter of care and counting to get the total number.
If you are familiar with the locality and are having this work done often you will know the length required and for what you can get them driven. The cutting of piles, after they have been driven and excavated around, is usually done by the general contractor and costs in the vicinity of 20 cents each. If unfamiliar with the locality and costs, you will call upon some one who makes this work his business and get a price per stick, driven,
Borings
On jobs of any size it is customary for the owner or architect to have borings made. A plan is then made showing location of each boring, with a record of the various soils and substances underlying the surface, and the depth of each is noted on the plan. By consulting this plan you can see just what kind of soil you have to excavate, whether shoring and pumping will be necessary, and at what depth a secure foundation is to be found.
Footings
We will assume that our building has concrete footings, so on the estimate sheet we put down this item, and after it make a "memo." of the mixture, so as to have it before us later when we put a price on the concrete, per cubic yard. The abbreviations as I have written them stand for 1 part of Portland cement, 3 parts sand and 5 parts broken stone. We will commence by taking off the footings the same way we went at the counting of the piles, taking' the outline, then cross walls in one direction, and so on. By carrying out the results we find that we have within a few feet of 68 cu. yd., and for such a mixture in this vicinity we make the price about $6.50 per yard.
If there were piles under the building the chances are that the footings or "pile cappers" would be of block granite. This would not change your method of taking off, and in carrying out the result you can make it either cubic yards or perches, according to the way you are in the habit of figuring stone work.
Foundation Walls, Walks, Grading
The common "unit" in stone work is the perch (24.75 cu. ft.), although many use the cubic yard. In taking off the quantity of stone work proceed about the same as for footings, outline first, etc. If the wall varies in height and thickness on the different sides of the building, set down the number of feet in length of each different height and thickness separately. Reference to the plans and sections will give you the desired information, and frequently the depth of foundations is shown dotted on each elevation, and numerous scale sections are often put on the foundation plans to show more fully all of various dimensions of walls. According to the figures I have assumed, there are slightly under 236 perches, so we carry out the cost on that number.
In order to set a price on the stonework you must know or find out the price per perch, or cubic yard, for the kind of stone called for, delivered at the site ; the number of perches that the average mason in your locality will lay in a day; the amount of attendance he will require; the quantity and quality of mortar required per perch, and the prices for sand, lime and cement. Knowing these, you can readily work out the probable cost per perch or cubic yard. For example, I will work out the cost of a perch of wall laid up of local rubble, according to present conditions here. It is customary in this vicinity for the party selling the stone to measure the wall when built to determine the number of perches and charge the purchaser the number thus found. Local rubble per perch, delivered, is $1.75 ; mortar, 1 part Portland cement at $2.20 per barrel, 4 parts sand at $1 per cubic yard, makes cost of materials for a cubic yard of mortar as follows :
One mason at 60 cents per hour, one laborer to make and carry mortar, and two laborers to handle stone to the mason and assist him in placing them on the wall, all at 30 cents per hour, should in a day, under normal conditions, lay from six to seven perches of wall ; call it six perches, thus :
In case of a wood building where there is an underpinning shown above grade, or a retaining wall, or any other stonework required to be laid up with more care, or of better stone than used in foundations, the dimensions should be taken off separately and price for same made to suit the quality of stone and kind of work required. Many builders figure this kind of work by the face foot instead of by the cubic yard or perch, but if you figure this way the thickness of the wall must be taken into account in making the price.
Concrete or Granolithic Floors, Walks, Etc.
The customary unit of measure for these items is the square yard (9 sq. ft.). The simple operation of getting the square feet in a space inclosed by walls or other bounds needs no explanation. If the plan is irregular in outline, divide by imaginary lines into several squares, rectangles or triangles, and compute the area in square feet, then reduce to square yards.
If there are, as is usual, different thicknesses on differently prepared foundations, with varying top finishes, each kind should be taken care of separately, and then the price of each made to suit the circumstances, See page 2 of the estimate sheet shown in Fig, 18,
This is simply a matter of obtaining the running feet of each size, and in making price, you must consider the depth the pipes are laid, and the nature of the soil. If your plan is large and
there are many long runs of drain, a very convenient way to take same off is to use a 5-ft. pocket tape. On a J-in. scale drawing multiply the number of inches of drain on the plan by 4 and you have the number of feet and no possibility of making a mistake in addition.
tion will usually tell you the depth below inlet of drain, diameter, and whether walled up or filled with coarse stone. By taking one typical well and analyzing as follows, determine the price : Typical well 4 ft. deep below inlet, 3 ft. diameter, filled to within 2 ft. of grade with coarse stone, equals 2 yd. excavation at 50 cents, about 1^ cu. yd. of stone, which can usually be gathered up around the premises (chips and refuse resulting from foundation and underpinning work), worth deposited in hole, say, 60 cents, representing 2 hr. for a laborer, plus 1 hr. more for a laborer to fill over and level off surplus earth, 30 cents, plus 1 hr. time for foreman at 50 cents to locate the well and oversee the operation, making total cost $2.40.
mine price.
I went to some length in analyzing the stonework and dry well, to give you an idea how to dissect, so to speak, anything upon which you wish to make a price. Consider each component part separately and compile the results. This method must be used to find the cost of any part or unit of measure met with in estimating the cost of building operations.
Grading
This item is largely a matter of judgment, especially if no great amount of earth is to be moved, and you do not have to purchase loam, as is usually the case in ordinary building operations. Thus you size up the situation and make up your mind about how many days it would take a certain number of men to perform the work, assisted, if necessary, by so many days' work for a team, plus a foreman's time to oversee the operation. If a large job, you have excavation of a certain number of cubicyards to bring lot to sub-grade, the purchase, teaming and spreading so many cubic yards of loam, etc., readily found by surveying the plans. You then figure out, at unit prices, the various items covering the work, for your total.
Sodding is always figured by the square foot or square yard. It will vary in cost from 6 to 12 cents per foot, according to circumstances. I shall not offer any explanation as to obtaining the quantity from plans, as it is a simple operation of finding areas.
Brickwork
If the building under consideration is a wooden structure, about all the brick necessary will be that for piers, chimneys, fire stopping, and possibly underpinning. For piers and chimneys the best way is to figure the number of brick per foot of height, multiplying by the whole number of feet. For instance, assuming five courses to 1 ft., an 8-in. pier has 10 brick per foot, a 12-in. 22J brick, a 16-in. 40 brick, etc. Set down on your estimate sheet the number, length and size of piers and carry out result later. See page 3 of estimate sheet, Fig. 19.
It may be here stated that brick from various localities vary greatly in size. The smaller brick lay up about five courses to 1 ft. The larger brick will sometimes lay up 14 in. in five courses. With the smaller ones it requires 22^ brick to lay 1 cu. ft. of wall. As this is the generally recognized number per cubic foot, I shall use it in treating the subject of brickwork; but in actual practice you will have to regulate the number of brick per cubic foot, or face foot for the various thicknesses of wall, to the size of brick you intend using.
Chimneys, especially without fireplaces, are also best figured by finding the number of brick per foot in height and multiplying by total feet in height. If there are fireplaces, find the number of brick per foot in the base and multiply by the number of feet in height to the point in chimney above fireplace, where it is drawn1 into the flue or flues, with necessary withes (partitions between flues in a chimney), proceeding with balance of chimney as for any ordinary one. You must also add enough brick to head over the chimney under the fireplaces and for hearths.
thus the explanation on walls will cover this item.
I think the best way to figure walls is to measure the face feet of each thickness, and after taking out the "outs" multiply by the number of brick per foot for each thickness. The prevailing custom in this locality is to allow openings out at about three-
quarter their size, unless they are very large, in which case we allow them out at full size. We make no allowance for very small "outs." It was at one time customary to allow the corners
of surveying the brick is to work from the various foundation and footing levels, at which the brickwork starts, up to the top of the first floor, then from top of first floor to top of second floor, and so on to the top of the structure.
Should the outside or any partition Avail be of uniform thickness through several stories you can simplify matters some by taking the total height of the several stories in one measurement. For the purpose of illustration, however, we will assume that the walls, both outside and partitions, are of various thicknesses not only from one story to another, but in each story.
Method of Procedure
Now with the basement or cellar plan before you and sections and elevations where you can refer to them, proceed as follows : Take a prominent corner of the outside wall and work around the entire outline of the building. For instance, on the side you have taken for a start the wall is figured 20 in. The elevation for this side shows from top of foundation (probably about 6 in. under finished grade) to top of first floor to be 3 ft. at one end and 7 ft. at the other, making an average height of 5 ft.; then set down on the estimate sheet as shown in Fig. 3, the dimensions 5 ft. x 60 ft. x 20 in. There are several windows scaling 3 ft. wide and with an average height of 4 ft. 6 in. ; then under heading of "outs" put down 3 ft. x 3 ft. x 20 in. x 4 (times) ; I am assuming four windows, and the size, 3 ft. x 3 ft., saves fractional figuring, and gives about three-quarters actual size.
Proceeding to the next piece of outside wall, set down as above, not forgetting that in taking the first dimension you have got the corner and should allow it off on measuring this wall. This would be 20 in. ; but in figuring brick I never work in any fraction of a foot for length, except 6 in. or J ft. Life is too short to work down any finer than this on brickwork, and if you were to work down to each actual inch in taking wall lengths and heights on a large building where there were 200,000 of brick, it might make an actual difference of 2000 or 3000 of brick, or from $40 to $60 at current prices of brickwork. This variation on a job of this size is of no moment, and there would be the difference between an hour and six or seven hours in taking off
arid figuring up the number of brick, to say nothing of the mental * ' wear and tear. ' ' Now, having taken your outside walls, proceed to take off the partitions.
Partition Walls
Begin with the thinnest walls, probably 8 in., taking all that run in one direction first, then all in the opposite direction next, followed by the walls that run at angles, setting down on a scrap of paper each length and adding up. Assume that we total up 62 ft. of 8-in. wall all the same height from a stone or concrete footing to top of first floor, which is 10 ft. 6 in. ; then set down on your estimate sheet 62 ft. x 10 ft. 6 in. x 8 in. Now take 12 in., 16 in. and any other thickness of walls, each in their turn, in the same manner that we took the 8-in. walls, and set down the dimensions. Then set down the "outs" for all these walls. Should any of the cellar be deeper than the 10 ft. 6 in.— the general depth assumed— take the one or more places that are deeper and set do-wn the length, by the extra depth, by the thickness. Having gone through the basement in this manner you are not apt to have missed anything or have taken any piece of wall twice. Now take the first story, working from top of first to top of second floors for height, proceeding thus to the top of the wall.
Now after you are through with the plan and are ready to figure out the number of brick, take your estimate sheet and do so, following the dimensions you have set down from the plans. In figuring up the number of brick, work out first the number of brick in chimneys and piers and set down to one side. Now you can figure all of the wall dimensions into cubic feet and add up ; take out the total cubic feet of "outs," obtaining the net cubic feet of brickwork and multiplying by the number of brick per cubic foot (22J) ; or beginning with 8-in. walls, get the total number of face feet less the face feet of "outs" in 8-in. walls and multiply by the number of brick per face foot for an 8-in. wall (15?). Proceed in a similar manner with 12-in., 16-in., 20-in., 24-in., etc., walls, adding the resulting number of brick for each thickness to the number previously obtained in chimneys -and piers for the total number of brick in the job,
Of course, the prices I have used above will vary with the locality; but by separating 1000 of brick, laid, into the above items and considering each item separately, you may readily obtain the cost in your locality.
Face Brick
In treating brickwork above I have assumed that the walls right through were of one kind of brick. While in some buildings you figure this will be the case, in more of them there will be several kinds of brick. For instance, the exterior on one or more elevations may be faced with selected water struck, or any one of the numerous colored face brick. Then, perhaps, the boiler room, elevator shaft, or some other parts of the interior, may be lined with glazed brick.
I have found by experience that you are less apt to make errors if you take off the brickwork of a building as though they were all of one kind and then proceed to take the face, glazed, hollow, or other kinds, separately; after computing the number of each kind take them out of the total survey of common brick as you would so many '"outs." See estimate sheet, Fig. 3.
Ground Brick
Often the arch brick and brick for angular corners, etc., have to be ground to the shapes required to properly execute the work. In cases of this kind, after having estimated the face brick, take off the surface feet of arches, etc., and after computing the number deduct from the face brick, as I have deducted face from common brick on the estimate sheet. Grinding arch and corner brick usually costs us in this locality about 5
cents each (labor of grinding only). We deliver to the parties doing the work sufficient brick and they grind each brick for its proper place in the arch, numbering them to correspond with numbers on a setting plan of arch, and deliver each arch packed in a barrel.
Washing and Pointing
In nearly all cases it will be necessary to point up the brickwork of exterior walls, also, around stone or other trimmings, windows, etc., before the job can be called complete. This is usually called for in the specifications. The only proper way to make a good job of this is from a swing stage, after the regular mason's stage has been taken down. In the large cities there are men who make a business of this class of work, and after talking with most of them in Boston I find that they have no systematic way of arriving at the cost of the work, it being largely a matter of judgment with them as to what a job will cost.
This is one of the items that you can best analyze while the plan is right before you. I go at it as follows : The men work in pairs— mason and helper— on a stage about 10 ft. long. I look at the plan to see how many times they will have to hang the stage and then judge as to about how long they ought to be coming down with the stage each time. For instance, we will say they have got to hang stage eight times, and will be one and one-half days coming down; we then have 12 days for the two men; the 12 days for the mason at $4.80, and 12 days for the tender at $2.40, making a total for labor of $86.40, to which we must add the teaming of the stage to and from the job ; use of, and wear and tear to same, say $15 ; brushes and muriatic acid, $6 ; a little cement, sand, etc., $5 ; all making a total of $112.40. Now I assume that the man wants a little profit, and put the job down for $125.
Waterproof Coating of Walls
Occasionally the inside surface of all or a part of the outside walls is coated with hot pitch or asphalt, or some of the waterproof paints now on the market. The cost is usually figured by the square yard. To determine the number of square yards it is only necessary to "survey" the inside surface of such walls
as are to be treated, taking out the larger "outs." This being a simple process, will require no explanations. With R. I. \V. paint so used on a large job recently done in Boston, the result was as follows:
Flue Linings
As a rule, nowadays, chimneys have terra cotta flue linings. In getting the number of feet of each size, refer to the basement plan. Look over the chimneys and see what the sizes are. For instance, you see that some are 8 in. by 12 in., some 12 in. x 12 in. and some 12 in. x 16 in. Set down on a piece of paper each size. Now take one chimney showing, for instance, in the cellar two 8 in. x 12 in. flues, lined ; refer to the elevation which shows the top of this chimney ; measure from point on elevation where flue starts to its intersection with roof, or to the top, if lining is carried to top, and set down number of feet under 8 in. x 12 in., twice for the two flues. Now follow this chimney up by referring to first floor plan. Here may be a fireplace, in which case the lining would start about 5 ft. up from floor and run to the roof boards or chimney top, as in case of other two flues. Assume this to be a 12 in. x 12 in. flue ; refer again to elevation, and scale on same from 5 ft. above first floor to top, and set down the number of feet under 12 in. x 12 in. Follow this chimney floor by floor to the top in this manner, and when completed take the next chimney, and so on until finished. Now add up total feet of each length and set down on your estimate sheet.
In figuring the price I usually add from 5 cents to 15 cents per foot to the cost delivered for handling from team, carrying and setting, loss from breakage, thus getting total cost per foot installed in building.
Floors
In nearly all cases where there are cut stone trimmings it is safer to get a sub-bid for the work, specially if there are mouldings, columns, brackets, carving, etc. If you have only a few sills, steps, lintels, etc., and have kept your eyes and ears open, you probably know about the price per running foot for the work in various kinds of stone and styles of cutting. Assuming that the trim is simple, take off and set down on your estimate sheet, Fig. 20, the number of feet and sills, lintels, etc., together with a little sketch of same, with a note on the kind of cutting, and later figure same up. Or, if you choose, go to a granite or limestone man and get his figure on your schedule as put down on the estimate sheet.
By careful tabulation of time on an average building containing $4000 worth of cut granite, in just such trimmings as I have used for example on the estimate sheet, I found the cost of all handling and setting of granite was 20 per cent, of the cost of the stone delivered. Further observation on other buildings has verified this cost. The mortar required for setting such granite as I have listed is amply provided for by the brick displaced by the stone, as it is not customary, in taking off quantity of brick, to deduct anything for stone or terra cotta trimmings, except in the case of some very large belt courses. So we put down for setting about 20 per cent, of the cost of the granite delivered at the site, or, in round numbers, $175.
Limestone
Practically everything I have said in regard to granite will apply to limestone, except that the setting, as a rule, I have found will cost only about 7 to 8 per cent, of the cost of the stone. There are several reasons for this, as follows: The granite usually sets in area ways; on top of rough foundation walls; in most cases one or two sides are rough splits, making
it hard to handle it on rollers; and in such cases as above it is usually hand set. Limestone, on the other hand, is sawed on the sides where the granite is split, usually sets in brickwork, thus giving a level bed to work from, and in most cases is derrick set, as it usually comes in places accessible to the derrick.
In order to prevent, as far as possible, the discoloration of limestone by the cement used in the mortar of adjoining masonry, it is becoming customary for architects to call for the painting of beds, backs and unexposed ends of all pieces of stone with one of the waterproof paints now on the market, such as " Antihydrene " or "R. I. W." waterproof, paint. Where this is to be done you will have to use your judgment as to about how much paint and labor will be required to do the work, as such work as this cannot be put on a yard basis; or in taking a bid for the limestone you can require stone to be delivered at the building painted.
Terra Cotta Trimmings and Floor Arches
In a general way there is no great difference between terra cotta used as trimmings and granite or limestone, except 'again in the setting. My judgment in the matter is that it will cost to set terra cotta nearly as much as granite, as in the burning a great many pieces are more or less warped, and in order to make courses appear as straight as possible the masons have to spend considerable time with it. Then, too, all of the hollow places in it, except those that overhang the ashlar line, have to be filled solid with brick and mortar; and in the case of cornices, more or less iron work has to be put in to anchor it to the walls. All these things tend to make the cost of setting high, and, as a rule, I figure about 20 per cent, of the cost of the material for handling same from cars to building and setting in place in the wall.
The various forms of terra cotta for floor construction are sold by the square foot, delivered. Any of the large concerns will quote you a square foot price on application. To this must be added the cost of centering, laying and mortar. The quality of mortar will, of course, be determined by your specifications. If you have framing plans showing all floor beams and girders, you can make a more accurate survey of the area than from the
TERRA COTTA FLOORS AND PARTITIONS 57
regular floor plans, as the floor openings are more clearly and accurately shown, and there is less on the plan to distract and confuse. If your building is irregular in plan, obtain the area of a floor as I have explained under the head of concrete floors. Set down your areas and "outs" on the estimate sheet and carry out the result in square feet and price later.
To determine the cost, erected in the building, we must add to the cost of the material per foot delivered, the cost of centering; carrying blocks; materials for making and the carrying of mortar; and the laying of the blocks by the masons. As the plank for centering can be used several times, it is only necessary when considering this item to put down a fraction of the cost of material. For instance, with spruce at $28 per 1000 ft., I should figure as follows:
Of course, the deeper the block the more mortar will be required, and also, as they are heavier to handle, a mason will lay less in a day. Then other circumstances may tend to slightly increase or decrease the cost of labor and mortar, and these must be considered and price made accordingly for each job.
For obtaining the number of square feet of terra cotta block partitions, begin with the basement plan, or, if there are no block partitions there, with the first floor plan. Take all partitions running horizontally, beginning at the top of the plan and working down to the bottom, setting down each measurement on a piece of paper. Then take all partitions running at right angles
to the ones just taken (vertically as you face the plan), also setting down measurements with former figures; then take all partitions running in any other direction. Add these results for total running feet of partition and set down on your estimate sheet the result of your addition multiplied by the height of story. For instance, 92 ft. by 10 ft., as shown on the estimate sheet. Now count your doors and other "outs" and take an average opening; for instance, a 2 ft. 8 in. by 6 ft. 8 in. door. The allowance made in which to set the frame plus the skeleton frame of spruce or coarse pine, usually set up from floor to ceiling before partition is built, will make the actual opening about 3 ft. 6 in. by 7 ft. 6 in. This makes the 26 sq. ft. "out." I find the general custom is to allow about one-half, as there is considerable loss by breakage in cutting blocks, and also extra time is consumed around openings. Thus on the estimate sheet I have allowed 15 sq. ft. per door, multiplied by the number of doors. Openings much smaller than doors I should ignore, and much larger ones set down separately, allowing, as the opening gets larger, nearer to the actual number of square feet in the opening. Proceed in this manner throughout the building, floor by floor, until the survey is completed. By taking off the partitions in the manner I have described, you will not be nearly as apt to get confused as you would be if you started at any point and tried to take partitions running in all directions as you proceeded. I should let -the figuring out of the number of square feet of terra cotta floors and partitions, the quantities of which we have put down on the estimate sheet, go until you have rolled up and put away your plan.
Price of Block Partitions
In making a price per foot for the blocks erected in the building proceed in the same way we did for establishing the price of floor arches, which, without going too much into detail, would be about as follows :
In making the price per foot for labor you must consider the number of feet in the job; the arrangement of the partitions, the height of the building, etc., as all of these are factors in making up your mind as to how many blocks per day a mason
and his laborers can lay. On some jobs the average will be as low as 125 blocks per day, while on others you can get it up to nearly 300. I have had one mason and one laborer, where conditions were extremely favorable, lay 300 blocks per day.
Reinforced Concrete Floors
As there are a number of systems of reinforced floors on the market, more or less complex, it will be better to get a bid from specialists to cover such parts of the work. However, if conversant with the system called for, and you can subdivide and analyze the materials and labor entering into it, make your own price. The explanations offered for obtaining areas and analyzing costs under the head of "terra cotta floor arches" would sufficiently cover this item.
Steel and Iron Work
Unless the plan calls for a limited quantity of structural sfteel and cast iron in such simple forms as beams, channels, columns, etc., without complex framing in the case of steel, and plain columns and plates in the case of cast iron, I would advise you to get a sub-bid from some one in this line of business. If, however, the quantity is limited, make a schedule on the estimate sheet, and after you are through with the plans figure it into pounds and carry out the price at so much per pound, erected in the building and painted if called for.
Referring to the estimate sheet, Fig. 20, the first item is one set of three 15 in., 42 Ib. beams, having four separators. By referring to Carnegie's, or any other of the rolling mill hand books, you will find tables giving size and weight of standard separators, and tables giving weight of bolts of all sizes, and thus you can readily figure out the weight of this set of beams complete, which would be as follows:
Total weight of set 2,583
Now while the cast-iron separators will cost a little less, and the bolts a little more per pound than the steel beams, their weight is so small a part of the whole weight that I would figure out the cost on the basis of the pound price of steel. Thus we would estimate as follows:
Steel beams made into sets and delivered at site, 3J cents a pound, erection and field painting f cent a pound, make a total of 4 cents per pound, set in building. On this basis the entire list of steel beams which weigh 6094 Ib. cost in the building $243.76.
located in the structure, and whether it is necessary to handle with jacks, hand rigging, or steam. Assume that the job is large enough to make it economy to set up a derrick and engine. This set of beams we have figured out come to the site on a team ; you put a chain 011 them, give a signal, and in five minutes they are up 50 ft. in the building, and set on the wall in their place. Now J cent per pound, which in this case is about $6.50, will pay the entire cost, including rental of engine and derrick, coal, oil, etc., if your rigging is constantly working. Add to this the cost of painting, which should not exceed another ^ cent per pound, and you have a cost of J cent per pound erected in the building.
On the other hand, you may have no steam rigging, and you will have to call out seven or eight laborers to roll .the set of beams off the team and then run them 40 or 50 ft. into the building on a block roller, and hoist with a hand rigging 14 or 15 ft. ; the whole operation, including shifting your breast derrick around and guying it, consuming three to four hours' time and a couple of hours for the foreman, and costing about as follows :
you have in hand.
In regard to putting a steam hoisting rigging on a job, let me say here that unless the building is either high, of very heavy construction, and of considerable area, thus enabling you to keep rigging working practically all of the time, do not install it, but use breast derricks with hand winches. The ordinary charge for use of a large derrick and engine is about $18 per week, the engineer's wages will be about $21 per week; two tag men $18 per week each ; coal and oil will cost about $10 per week, which add up to $85. Then the cost of teaming the apparatus to and
from the job, setting up derrick, and raising it from floor to floor as the work progresses, will cost perhaps $250 more. Now, perhaps the outfit will be in use 10 weeks, which will make a total cost of $1100. You can readily see that unless there is considerable heavy material to handle, it will cost less to put it up in some other way.
Go through your plan and make a list of the structural cast iron. This you can also figure into pounds and carry out your price, after you have laid aside the plan. Under the same conditions, the cost of setting and painting will be about the same as for steel. As a rule, cast iron costs less per pound, in such forms as I have scheduled, than steel, and you will have to acquaint yourself with the prices in your neighborhood. In carrying out cost on the estimate sheet I have allowed 2^ cents per pound, which is the average for such shapes in this vicinity.
If the plans in hand call for steel that is very complex in framing, or of a decided^ special character, boiler plate or cast iron facias and column casings, fire escapes, iron stairs, cast or wrought iron grills, etc., you will have to have a sub-bid from someone in this line of business. All small iron work, such as anchors, timber dogs, bolts and joint bolts, truss rods and straps, and joist hangers, you can easily figure yourself, first making a list of them on your estimate sheet. Anchors, dogs and standard hangers are sold at fixed prices, which you can obtain. The other small iron can be figured into pounds, and the pound price obtained, the cost determined. The cost of setting all this small iron is ordinarily covered by the prices you will set on the parts of the work in which they are used. For instance, in figuring floor frame, the price you use for labor, per 1000, should include setting hangers, dogs, joint bolts, wall anchors, etc.
Marble, Mosaic and Terrazzo Work
As a rule, most marble work that goes into buildings is of such a character that it will be necessary to get a subbid from a marble worker. However, if it is very plain work, and you choose to inform yourself on the prices per square foot for the several kinds of marble most in use, and your judgment is good in forming* an estimate of the labor and materials required to set the work up, you can make a price that is very close.
Mosaic floors are easily figured if they are of the ordinary patterns, such as a plain field, with simple isolated ornaments and line borders of different colors. The prices for field, borders, and ornaments in each locality are practically standard, and thus making a price for a mosaic floor simply resolves itself into the number of square feet of field and border, at their respective prices per square foot, plus so many ornaments at so much apiece, plus so many square feet or square yards of concrete foundation, of a given thickness at its price per square foot or square yard.
Terrazzo floors also are laid at standard prices with which you can easily acquaint yourself. The price will vary from 15 cents per square foot in very large areas, say 5000 sq. ft. or more, to 24 or 25 cents for the ordinary job of several hundred square feet and up. If in very small quantities, say less than a couple of hundred feet, or if laid between strips of marble or slate, cutting the floor up into comparatively small panels, the price will vary from 30 to 40 cents per square foot. This floor, like a mosaic floor, also has to have a foundation of concrete prepared for it, and the cost of same would be worked out as any other job of floor concreting would.
Roofing and Metal Work
Slate roofing is easily figured by any one who can measure the area of a roof. Quotations can always be obtained from dealers at a few moments' notice, for slate of almost any size or color. Then you analyze as follows, and determine the price per square (100 sq. ft.) laid on roof:
A 10 x 20 in No. 1 Monson black slate bored and countersunk per square, at site, $8.20 ; galvanized nails, 2 lb., at 5 cents per pound, 10 cents ; tar paper at 2J cents per pound, 1^ Ibs. per yard, makes 42 cents per square; labor of putting on paper, handling and laying slate, $3 per square, making total of $11.72 per square complete. Now, this multiplied by the number of squares, of course gives you the cost of your roof. While I have set the labor above $3 per square, this would vary from $2 to $10, according to the shape of your roof.
The former price would pay (in Boston) for a perfectly plain roof, while the latter price would not be high for some roofs which are all hips, valleys, towers, etc. Occasionally in putting on a slate roof a certain number of course at eaves, ridges, valleys, hips, etc., are called for to be bedded in elastic cement. This increases the cost of labor per square, plus the cost of the required amount of elastic cement. In cases of this kind I would put down on the estimate sheet so many squares at the price I had worked out for the roof generally, then put down the number of squares bedded, and multiply by the additional cost per square. To bed slate requires about 100 Ibs. of elastic cement to the square, the cost of which would be about $3 and it would make the labor cost from $2 to $4 additional. Now, as we have above assumed, a comparatively plain roof, the additional cost on the number of squares which are bedded would be as follows :
The item of slating we will not carry into the estimate sheet, as, while we are dealing with hypothetical building, from the general dimensions and materials I have assumed, such a building would have some kind of a flat roof, such as tin, copper, plastic, or composition (tar and gravel).
In the case of composition roofs, the cost per square will depend upon the quality and number of layers of paper used, whether mopped and graveled in coal tar, pitch, or asphalt, the method of laying and mopping the paper, and the cost of labor. Only an experienced roofer can carefully analyze the cost per square, but in every locality there are standard prices for the several grades of composition roofs most called for, which prices it is your own fault if you do not know and when conditions are normal you may use. If conditions are abnormal, it becomes a matter of judgment with the roofer as to what the probable cost will be, and if your judgment is good you can probably arrive at the result as well as the average roofer. In taking off roofing from plans you would proceed as in any other case where you simply want the square feet. In setting down on estimate sheet I should put the number of squares, as in most cases you will have only to make several multiplications, taking but two or three minutes, and it avoids making your estimate sheets too numerous. If there are skylights, scuttles, etc., in the roof, it is not customary to figure them out, unless they are quite large, say 100 sq. ft. or more, as the extra labor involved cutting and flashing around them offsets any saving in materials effected.
The price per square for the roof usually includes the edge cleat, and flashings around chimneys, scuttles, skylight curbs, party and battlement walls, to a total width of 8 or 9 in. ; any more flashing than this must be figured by the square foot or square (100 sq. ft.) at the unit price for the kind called for. Such flashing might be zinc, tin, galvanized iron or copper. Reference to your plans and sections will show you the heights of skylight curbs, walls, pent houses, etc., that require covering, and obtaining the square feet is a simple matter. In this case, as in the roofing, you can set down the number of squares and carry out your price later. Thus, on estimate sheet we have put down seven squares of 16 ounce copper, and four squares 24
keep informed as to same.
At the present time, in this market, 16 ounce copper flashings, roofing, etc., are worth $40 per square. Zinc, tin and galvanized iron are all worth about the same in the above situations, and a fair price for them to-day would be $12 per square.
Metal Skylights
Ordinary galvanized iron skylights, hipped, with condensation gutters, and glazed with \ in. wired glass, furnished and set complete on curb already prepared, are worth about 75 cents per square foot measured flat. Thus, if your skylight opening measured over all, on the outside of the curb, 6 ft. by 10 ft., we would call it a 60-ft. skylight, and at the price I have used above would be worth $45. If a skylight of the character just described were either very small or very large the cost per square foot would be greater than quoted. Take, for example, a skylight 3x4 ft., which is 12 sq. ft. The laying out would take just as long as for the 6 x 10 ft. one. A brake would bend a rafter bar for the larger just as quick as for the smaller. The difference in labor, making, erecting and glazing might be 12 hr., which at 45 cents per hour would be $5.40. In the stock the savings would be about as follows: About 35 sq. ft. of galvanized iron at 4 cents, making $1.40; 50 cents worth of solder; about 60 sq. ft. of glass at 24 cents per foot, amounting to $14.40. Thus the total saving in cost between the larger and smaller skylights would be about $22. This would make the 3 x 4 ft. "skylight cost $23, or nearly $2 per square foot. You can readily see from the above analysis that, as the size decreases, you must increase the price per foot. In the case of very large skylights, the increase is mainly caused by light structural steel reinforcement required to make the skylight not only self -sustaining, but capable of withstanding snow loads.
In the average job the skylights met with are of such ordinary sizes that the standard price, with such adjustments as your judgment dictates, can be safely used. For your guidance, I will give a few more prices on skylights that might be termed
"Standard." A 16-ounce copper skylight similar to the first galvanized iron one described is worth about $1.20 per square foot; skylights that pitch both ways, having gable ends formed by the curb, are worth about 10 per cent, less than hipped sky-
lights. Flat skylights, that is, those having only one pitch, and that about the same as the roof in which they are located, are worth in 16-ounce copper about 90 cents, and in galvanized iron about 50 cents, per foot.
rough plate and J in. wired rough plate glass cost about the same, thus the use of either would not affect price ; £ in. rough plate (not wired) would decrease the price about 15 cents per square foot of glass area (not curb opening area).
As wall copings are usually of only three or four sizes, it is not difficult to keep posted on the prices they are each worth a running foot, applied to the wall, both in galvanized iron and copper. In case of any ordinary size, in either metal, the labor is substantially the same. As an example, we will work out the cost on a 24 gauge galvanized iron coping for a 12 in. wall. Allowing 5 in. to turn down each side of wall and bend at edge to form drip we have a total width, extended, of 22 in. The chances are that a 24 in. wide sheet of metal would be used, and if the 2 in. were cut off it would be waste, so that the metal worker would probably turn down a little more each side and use the whole sheet ; then we have 2 sq. ft. of metal at 4 cents, making 8 cents, and labor to make and apply 15 cents, making cost per linear foot 23 cents. Now, as the metal man wants a little profit, the fair cost per foot for you to figure would be 25 cents. If copper was used, the change in price would come on the difference in cost between galvanized iron and copper. To-day, with copper at 27 cents per pound, the 2 sq. ft, would cost 56 cents, thus the coping would cost the metal man 48 cents more per linear foot. If you were covering a 16-in. instead of a 12-in. wall, 4 x 12 in. more of metal would be required per linear foot, as 4 in. is onesixth of 24 in. (the extended width used to make the coping we have worked out a price upon) we must increase the cost of the stock per linear foot one-sixth. So instead of 8 cents we have 9 1-3 cents per foot for stock, labor being practically the same, the cost is increased to 24 1-3 cents per foot. In putting the metal man's profit on to this we will take up the fraction by adding 2 2-3 cents, thus giving us 27 cents as the price to use in our estimate. You can see how easy it is, from the above illustrations, to figure yourself the cost of skylights and copings, if you take the little trouble required to keep posted on the cost of sheet metals and get a line on labor, as performed by metal workers, by keeping your eyes and ears open and asking your metal man a few leading questions now and again.
In the case of metal cornices, bay windows, etc., the work is of such a character that the only sure way of getting a close estimate is to call in the metal man. While you could in most cases figure out the required amount of stock as well as the average cornice maker, only his experience can determine the probable cost of the labor. As the labor on cornices, etc., is frequently from 75 to 95 per cent, of the total cost, you might get very far astray by trying to figure such work yourself.
Frame, Studding and Furring
As estimating the carpenter work will probably prove of more than usual interest to a large percentage of the readers of this work, I shall try to be a little more explicit and go somewhat more into details.
As my estimate sheets have assumed a brick building, some of the items under the head of carpenter work will not appear on them. Nevertheless, I shall try and make the text so clear as to render it unnecessary.
My observation has led me to believe that a majority of the carpenters, in estimating their work, figure out the quantities of lumber, hardware, etc., and put a price on them, and then "lump" the labor, judging, or guessing, the latter amount. Now, if a man is doing one class of work all the time, for instance, dwellings costing three or four thousand dollars, he can judge the cost with considerable accuracy ; but if he was to estimate a wooden building of an entirely different character, such as a freight shed or a coal pocket, his judgment, or guess, in the matter of labor, would probably be far astray.
In the various classes of buildings, the labor bears a certain average ratio to the amount of stock. If you build a freight shed and it costs you $5 or $6 more per 1000 ft. to frame and erect same than the generally recognized cost, you have a poor crew, or they are badly managed, or both. On the other hand, if you can hold the cost down $1 or $2 from the recognized cost, you have an exceptional crew, well managed.
In figuring practically all branches of carpenter work I advise the builder to determine a cost per ' ' unit ' ' installed in the building. By a system of time slips, similar to the ones explained and illustrated in Chapter 25, you can soon establish labor costs upon which to base your estimates.
Under this head include all girders, sills, floor joists, rafters, and collar beams. The unit of measure I make 1000 ft. board measure. If, as probably would be the case, we had framing plans, the first thing to do is to separate them from the regular plans and elevations, putting the latter to one side for the time being.
Take the first floor frame, and begin with the heaviest timber first, probably the girders. Now, on the estimate sheet put down the heading thus: Spruce (or H. P.) frame; then piece by piece set down your schedule as follows :
Floor Joists
Look over the plan and see what your largest floor joists are, usually under partitions, or trimmers and headers around stairs or other openings. Put these timbers down next. Now take off the regular floor joists, beginning at one side or the top of the plan, according to the way the joists run; taking each "bay" or division complete before proceeding to the next. In this way continue listing frame on all floors and the roof.
You are probably sufficiently able to figure the schedule into board feet, so I will offer no explanations. This accomplished, we must determine the percentage of waste and add this to the net schedule. On a frame of comparatively heavy timber, if sawed to your order, the waste should not be over 10 per cent. If you do not have time to order the stock in from the mills, but must take it out of stock from local lumber yard or wharf, the Avaste will run from 10 to 20 per cent. By studying your building a little to see if the time required to put in the foundation is going to permit the ordering of frame from the mills, leaving any leeway for possible delays in freight, you can make up your mind as to the waste. The prices you know or can readily obtain. Such timber as I have listed should be installed in the building
While the process just described is the most accurate, there are other methods for determining the amount of frame that are quicker, and the results are close enough for all practical purposes.
If the plan is very regular and there is considerable uniformity in lengths of timber, I advise that you schedule the quantities as we have just done. If, however, the plan is irregular and there are all sorts of lengths of joists, the number of board feet can be obtained from the area of the floor. For instance, quite a part of the floor is of 2 x 12 in. joists, 16 in. on centers, and the balance of 2 x 10 in. joists, 14 in. on centers. Then we proceed in this manner : On a scrap of paper set down the several dimensions that will give you the area of that part of the floor that is of 2 x 12 in. joists, thus:
figured out they equal 1443 sq. ft. Now, if these 2 x 12 in. joists were 1 x 24 in., and they were all laid down flat, they would not only cover the 16 in. from one center to the next, but lap onehalf over on the second space, thus, as the 1 x 24 in. is the 2 x 12 in. joist changed to board feet, and laid flat as above, they cover the whole area one and one-half times, so one and one-half times the area of floor occupied by these joists, or 2165 ft., is the number of feet board measure (net) of lumber required. Now, by adding the percentage of waste you have arrived at a sufficiently correct result with less trouble than by scheduling. By the same reasoning any size or spacing of joists or studding can be figured into the number of feet board measure of stock required to joist
this rule in your mind.
Take an area of 962 sq. ft. of flooring having 2 x 10 in. joists 14 in. on centers; 2 x 10 in. changed to board measure equals 1 x 20 in. joists, thus as 14 in. is to 20 in., so is 962 sq. ft. to the number of feet board measure of timber in the floor. Put in the form of the examples in proportion you used to see in your arithmetic, it looks as follows :
words, it is as follows : as to every 14 in. there are 20 in. of lumber, then the relation of the area (962 sq. ft.) is to the result we seek as 14 is to 20, as 14 is seven-tenths of 20, then 962 ft. is seven-tenths of the number of board feet. Work this out and you will find the result to be 1374 and a fraction, as shown by the example in simple proportion.
This last paragraph is somewhat verbose, but I want the less educated of the readers to grasp the principle upon which this method of figuring is based. In using this method of figuring, do not take out the stair, chimney and other openings unless they are very large ; even then they should not be taken out of their full size, as the larger joists around the opening usually offsets the difference in board feet that would be saved if they were figured out. In figuring a first floor by this rule the girders should be added to the result obtained, and in case of a frame structure the sills also.
Figuring Rafters
This method is by far the quickest and most accurate by which to obtain the quantity of frame in pitch roofs, but care must be taken to add to the result thus obtained from the area, the hips, valleys and ridges. Any roof that is at all cut up with hips, gables, dormers, etc., must of a necessity have so many different lengths of rafters that the scheduling piece by piece is a laborious job; so also is the figuring of the schedule thus obtained into board measure laborious. These two facts, coupled with the fact that the roof framing plan does not show the rafters at their cor-
Any complicated framing, such as trusses, etc., should be considered separately, and the price must be worked out to suit the complexity of the design. In case the building you are figuring has framing of this character, make a new heading on your estimate sheet, such, for instance, as "Truss Framing;" now set down under this the schedule of sizes and lengths and figure out later. The labor of framing and erecting trusses often runs from $25 to $75 per 1000 ft. board measure of stock.
Next time you have a job with one or more trusses to build note the quantity of stock and keep a memoranda of the labor required. You can then figure out a labor cost per 1000 ft. that will guide you the next time you encounter something similar when estimating. Bear in mind, also, in figuring this special framing, that in most cases the stock will cost more per 1000 on account of unusual sizes and lengths, the elimination of certain defects permissible in "merchantable" lumber, the planing of the stock, etc.
If you have ever kept any account of the labor required to install studding and furring in a building you doubtless found that the cost per 1000 ft. was several times that of other framing. Inasmuch as there is so great a difference in cost, I think it advisable to treat the two classes of frame separately on nearly all occasions. Under this head I include all wall framing, including posts and girts, all stud partitions, rafters, collar beams and hanging ceilings where the stock used is smaller than 2x6 in., strap furring on ceilings, brick walls, etc.
Outside Walls of Frame Buildings
We will begin with the outside walls of a frame building; usually there would be but two or three heights of plate. Assume the main house, two stories high, with 20 ft. posts and an ell one
story high with 10 ft. posts. "We begin by obtaining the girt of the main house, say 118 ft. ; this multiplied by the height, which is 20 ft., gives us the area of the outside walls of the main house. Now we have for "outs" the windows, doors, and the place where the ell adjoins the main house. As the door and window openings are of no great size, and the studs around them are usually heavier than the rest, we take no notice of them. Where the ell joins the main house is probably a partition, and as this will be taken with the other inside partitions later, we take the space out. Call this space 18 x 10 ft. Now take the girt of the ell, which will be three sides of it ; call it 58 ft. ; then the area of the ell walls are 10 ft. by 58 ft. For results we have :
Total net area 2,760
Except for the posts and girts and around window and door openings, the wall is probably of 2 x 4 in. studding 16 in. on centers. Now, if we change our 2 x 4 in. studding to board measure we have 1 x 8 in. Thus, on 16 in. spacing, our area of walls is to the quantity of studding as 16 in. is to 8 in. As 16 in. is twice 8 in., then the wall area (2760) is twice the number of board feet in the walls. But this does not compensate for the additional frame required for posts and girts. We have allowed the area of the door and window outs to compensate for the increased size of studding around their openings. I have found from experience in ordinary frame buildings, with 4 x 8 in. posts and girts, 4 x 4 in. plates and 3 x 4 in. studs around openings, the area, as we have just figured it out, so nearly equals the number of board feet of frame in the walls, plus what we would naturally add for waste, that if you assume the said area to be the number of feet board measure you are sufficiently correct. So under the heading of ' ' Stud and Furring, ' ' on your estimate sheet put down this item as follows : 2760 sq. ft. outside walls ; this followed by your other items of studding and furring, can be carried out into a total number of feet, board measure, and a
Stud Partitions
In measuring the plans for stud partitions follow the same method that I have used in the case of the brick walls in the basement and the terra cotta block partitions. The chances are that the partitions will be of 2 x 3 in. and 2 x 4 in. studs 12 and 16 in. on centers, and occurring on all floors. Take the floor plan of the basement, first or other floor that you are going to measure
and begin at the top of plan, taking all partitions of 2 x 4 in. studding running horizontally as you look at the plan ; then take all running vertically, following this by taking the partitions that run in other than these two directions. On a scrap of paper set down the total running feet of partitions; now refer to the sectional plans for the height. Having found same, perform the multiplication, and the result will be the square feet of partitions, of 2 x 4 in. studs, for this story. Next take the partitions of 2 x 3 in. studs in the same manner. Continue throughout the entire building in this manner, floor by floor, performing all the multiplications as you go. When this is done and they are all added up you will have the total area of all partitions of each size of studding. Then we set down on the estimate sheet the resulting areas to be figured into board feet later. You will doubtless note the fact that I have paid no attention to the door openings in these partitions. As the studding is almost invariably doubled around openings, not considering them will compensate for the extra studding thus required. Using the area again as a basis from which to figure, the three items of studding I have entered on the estimate sheet result as follows : 2 x 4 in. studding changed to board measure equals 1 x 8, or 8 in. of stock to every 1 ft. of partition ; as an example in proportion expressed
316J ft. board measure. The number of feet board measure for the three items of studding that we have figured out above are "net," and to them we must add a certain percentage of waste. There is no item of stock that goes into a building upon which there is as much waste as studding. Not one man in 20, in ordering studding, gets enough to do the job once in five times. Figuring studding as above, one-fourth, or 25 per cent., will cover the waste, if the pieces are used up as they should be.
Furring
In figuring the quantity of furring, work from the areas to be furred, determining number of board feet by proportion. In taking areas from the plan, work as follows: Take the first-floor plan (or basement plan if there is any ceiling or wall furring required there) and obtain the area of same inside of walls. Of course the ceiling is of the same area as floor, thus in the floor area you have the ceiling area. Now, if any brick or stone walls are furred, obtain running feet of these walls and multiply by the height of the story. These two results added give you the total area to be furred in this story. In this manner continue throughout the entire building, adding all the areas thus obtained together and setting down the result on your estimate sheet as I have done. Now, using the rule of proportion again, taking the first item of furring to demonstrate same, we work out
Hanging Ceiling
Frequently the framework of a ceiling, where there is no attic, is of light members hung from the rafters or roof joists ; in such cases obtain the area of the ceiling from the upper floor plan and use the rule of proportion to find the quantity of stock in board feet. Thus, referring to the estimate sheet, we assume a ceiling of 1 x 6 in. rough spruce, 20 in. on centers, of 3104 sq. ft. area. This is expressed and performed by proportion, as follows :
The stock with which to hang the ceiling frame to the rafters or joists is usually refuse picked up around the building, and your estimate will be sufficiently accurate if you do not consider same at all.
Bridging
If the floor joists are cross bridged in the center of the span, proceed as follows : Beginning with the first-floor framing plan, scale each stretch of bridging, setting down on a scrap of paper ; in this way go through the entire plan and add for the total length. Assume the bridging to be 1 x 3 in. and the length measured on plans to be 964 ft. The diagonal distance between timbers (from the top edge of one to the bottom edge of the next joist) is near enough to one and one-half times the straight length to always call it so. As the two pieces of 1 x 3 in. equal a 1 x 6 in., we have one-half of one board foot for each extended linear foot of bridging. Add to 964 ft. 482, or one-half itself, to give us the extended or diagonal length of the bridging, and we have 1446 ft. As there is \ ft. board measure of each foot in length of bridging, thus one-half of 1446, or 723 ft., is the number of feet, board measure (net), of stock required.
As rough spruce, furring, bridging stock, etc., frequently gets put to a good many uses, such as staying, bracing, staging, etc., before being used where intended, 25 per cent., or one-fourth, is little enough waste to allow over the net survey. As the number of board feet in all of the, items under the head of studding and furring is 6875 ft., net, and plus one-fourth for waste makes 8594 ft., we will call the quantity 8600 ft, or eight and sixtenths thousands, expressed decimally 8.6.
The average cost of labor on these parts of a building, with carpenters' wages at 41 cents per hour, should be right around $20 per 1000 ft. The quantity of nails per 1000 ft. of stock will be about double that required for frame. Thus we work out a price as follows :
Boarding and Measuring Roof Surfaces
As there is quite a difference in labor between square edged and matched boards, that may be used for wall and roofing covering and under floors, I think it is advisable to survey and keep quantities separate. Square edged boards are usually used for under floors, pitch roofs and wall covering. Obtaining the areas of floors and walls has been sufficiently explained under other headings, consequently I shall not go into the matter here. However, not having explained the method of obtaining pitch roof
areas, I will endeavor to do so now. With most plans there is a drawing of the roof showing all ridges, hips and valleys. Where there is no such drawing the lines of the roof are sometimes indicated by dotted lines on the attic floor plan. Not infrequently the roof is shown in no other way than by the elevations. In case the roof is shown by either" of the first two methods, you must refer to the elevations for part of the dimensions. In order to make matters as clear as possible, I will demonstrate by a few drawings.
In Fig. 23 we have a roof plan. I am paying no attention to architecture in this plan ; simply drawing a roof that has hips, valleys and dormers in order to illustrate all ordinary roof forms. Figs. 24, 25, 26 and 27 are the four elevations and are of
the correspondingly numbered sides as Fig. 23. We will begin by obtaining the area of the section of roof marked A in Fig. 23. By scaling the ridge we get 32 ft. 6 in., and by scaling the roof at gutter line, paying no attention to the wing that projects 2 ft.
on this side, we get 45 ft. Now, by referring to the elevation of the front, Fig. 26, we obtain the length of the rafter, which is 17 ft. 9 in. This section of the roof, as developed in Fig. 29, is called a trapezoid. We will now obtain the area, for the time being paying no attention to the gap made by the roof over the projection of 2 ft. As the length of roof is 32 ft. 6 in. at the
ridge and 45 ft. at the gutter line, we next obtain the average width. This is done by adding both of the above dimensions together and dividing by 2. We find this to be 38 ft. 9 in. Thus this section of roof measures 17 ft. 9 in. by 38 ft. 9 in., making the area 688 sq. ft. Now, out of this area we take the triangle covered by the roof of the projecting wing. Refer to either Fig.
23 or 24 and scale the distance across the projection where it intersects the main roof at the gutter line. We find this to be 19 ft. Refer to Fig. 26 and scale the distance from gutter line to the intersection of the ridge of projecting roof with main roof, which we find to be 13 ft. 6 in. Thus we have a triangle, the base of which is 19 ft. and the altitude 13 ft. 6 in. To obtain the area of a triangle we multiply the altitude (13 ft. 6 in.) by one-half of the base (9 ft. 6 in.), which gives an area of 128+ sq. ft. By subtracting this last area from the 688 sq. ft. we have the net area of this side of the roof, which is 560 sq. ft.
In order that the reader may understand the theory of computing the area of triangles picture in your mind a triangle such as the one we have just figured out, or the one shown in Fig. 28, which is a developed plan of the rear section of roof E. If you were to cut this triangle in two, as shown by the dotted line in Fig. 28, and took the half marked X and turned it around so that it occupied the space marked X', you would have a rectangle, one dimension of which would be the altitude and the other onehalf of the base of the triangle. The same principle applies when we obtain the average length of the roof section shown in Fig. 29. Here the space X, if cut off, turned around, and made to occupy the space marked X',
time. The way I should proceed
to obtain the area of this side of the roof would be as follows : If the plans are not too large, spread the four elevations out on the table so that you can see them all at once and reach them with your rule to scale lengths. We will take for this illustration the side of the roof marked B in Fig. 23. Either on the roof plan, Fig. 23, or the side elevation, Fig. 25, scale with the rule the distance from gutter line to ridge. The number of feet you read mentally, at once ; half this number of feet mentally before lifting your rule and place the point of your pencil at the middle of the distance ; now holding the pencil where you placed it a moment, turn your rule around, let the side of it from which you are reading touch the pencil point and lay approximately parallel with the gutter or ridge lines, as drawn on plan. Having done this read immediately the distance from the right angled or rake end of the roof to the point on hip where the rule crosses it. The whole operation is but the work of a moment, and we have obtained the average length of
this section of the roof. We will not bother with inches and will call the length thus obtained 39 ft. Now, refer to the front elevation, Fig. 26, and scale the length of the rafter, which, in round numbers, is 18 feet— again ignoring the inches— and we have obtained both dimensions of the piece of roof, B, and can compute the area. Thus we have 18 X 39 ft- = = 702 sq. ft.
Out of this we must take the area occupied by the walls and roof of the dormer window. Refer again to side elevation, Fig. 25 scaling width of dormer ; note mentally 6 ft. ; then refer to the
front elevation, Fig. 26 ; scale from the intersection of the front wall of dormer with main roof to the average or center of the dormer roof, as seen in the elevation D, Fig. 26 ; read 10 ft. and mentally calculate the area 6 x 10 ft. — 60 sq. ft. Subtract the latter number of square feet from 702 sq. ft. and we have 642 sq. ft. as the area. Thus we see the whole operation is done in a minute's time, making no drawings, half the calculations being done mentally while shifting the rule from scaling one dimension to another, and a result thus obtained is sufficiently accurate for all practical purposes.
Proceed in the same manner to get the area of the roof of small dormer on this side of the main roof. First refer to the side elevation, Fig. 25. Scale rafter and read 5 ft. ; now refer to either of the end elevations, Figs. 26 or 27, or to the roof plan, Fig. 23, and scale the section of roof marked D across the center (that is, half way between the dormer cornice and ridge line), and read
8 ft., the inches again being left out of consideration. Thus one side of this roof is 5 x 8 ft., equaling 40 sq. ft., which multiplied by 2 gives the area of both sides of the dormer roof. Fig. 32 is a developed plan of one side of this dormer roof; the dotted line across it shows where to get the average length.
As it usually takes but three or four minutes to figure the area of the average roof, I think it better to make the calculations on a scrap of paper and then carry to the estimate sheet the net roof area, as follows: 1669 sq. ft. (net roof area), add to this, if the item is going on to the estimate sheet under the head of frame, the size and spacing of rafters, thus: 1669 sq. ft. (net roof area) 2 x 8 in.— 20 in. o. c. Having the information on your estimate sheet as last shown, you can figure the amount of frame by proportion, as previously explained, and your area for boards, and shingles or slates, is right before you. Do not think, because I put down the areas accurately, not eliminating the odd inches, and figure out the result decimally, that I would do this myself in actual practice, or expect you to do it. I do it here because I do not want my mathematics criticised, and in order to carry out an
exact result of the area,' as shown by the plans and elevations above referred to. It also shows to what accuracy you can go, and withooit much trouble, if there is any reason for so doing. The time to make this roof survey is when you have reached it, surveying under the head of * ' frame. " As I explained under that heading, it is necessary in computing the feet, board measure, of the frame in a roof, that there should be added to the result obtained from the area the schedule, or feet board measure, of the hips, valleys, ridges, etc. I will now endeavor to show you how to obtain sufficiently accurate lengths of these members. In doing so I will use Fig. 23 of the diagrams. The lines which represent the hips and valleys on this plan are the bases of right angled triangles, of which triangles the rise of the roof is the altitude and the hip or valley rafter the hypothenuse. Now if
ONE SIDE OF DORMER ROOF
we scale the length of the hip or valley as indicated on the plan of the roof, Fig. 23 from & to c, we have the length of the base of the triangles, after which refer to an elevation (in this case either Fig. 24, 26 or 27) and scale the height, or rise, of main roof, and the lower roof covered by the sections marked C. The results in this case are the altitudes of the triangles. Having the lengths of any two sides of a right angled triangle, the third can be obtained by a process in arithmetic. However, as this involves figuring in square root, and all you want is an approximately correct length of the hip or valley upon which to base an estimate, it may be quickly laid out and the required length obtained on the roof plan, Fig. 23. As the two hips on this plan are at right angles to one another, let one of the hips represent the base of the triangle as from & to c. As you have scaled the rise of
the main roof and found it to be 12 ft. 6 in., scale from c along the other hip 12 ft. 6 in., and make a dot with the pencil at this point (d) ; now turn your rule around and scale from & to d, as indicated by the dotted line, and the distance as read from the rule will be the length of the hip or the remaining side of the triangle called the hypothenuse. The same process applied to the valley, where the rise of roof is 9 ft. 6 in., the scale distance on the dotted line from b to d gives the length of the short valley. In the case of this roof the length of the long valley, which runs to the ridge, would be the same as .the hip.
In the case of roofs of different pitches intersecting, the lines on the plans indicating the valleys would not show at right angles to one another. In such cases assume the line representing one valley to be the base of the triangle and lay off at right angles to this by your eye the rise of the roof, for the altitude of the triangle, making at the point thus obtained a dot with your pencil. Now scale the uncompleted side or hypothenuse of the triangle thus laid out, and you have the length of the valley. All hip and valley rafter lengths may be obtained from the plans in this way and set down piece by piece in your "frame" schedule, to be figured into board measure later. The lengths of the ridges may be scaled directly from the roof plan, Fig. 23, or from the elevations, Figs. 24, 25, 26 and 27, as their true lengths are shown in each.
You will probably notice that in figuring out the wall area of a typical frame house I did not include the gables. All gables being triangles, or in the case of Gambrel roofs a trapezoid surmounted by a triangle, I purposely delayed touching on the subject until after I had demonstrated by the drawings of a roof how to obtain areas of irregular shaped planes. In actual practice the gable areas should be taken off at the time of surveying the walls of the building, the total area being entered on the estimate sheet under the head of "studding." This item of studding should be noted "outside walls," so that it is distinguishable from the partition areas, thus making it possible to look back for area when figuring boarding and clapboards, or other wall covering. Sometimes under floors, and even walls, are boarded diagonally. This increases the waste somewhat, and in most cases about doubles the labor. When the above is the case, make a separate item and figure out the probable cost at which
to carry out your price. I usually make a few diagonal lines after the heading of the item covering this part of the boarding to distinguish it from ordinary boarding, thus: '* J-in. square (or ni'tch'd) spruce ////."
Matched boards are always used under slate, metal or composition roofs and often for wall boarding. Theoretically there is more waste on matched than square boards, as the loss in milling and matching is surveyed in when boards are marketed. In actual practice, unless the boards are very narrow, say less than 5J in. face, the waste would not be any more than on square boards used in the same place. The principal reasons for this are that the matched boards are usually of sounder stock, more uniform in widths and lengths, and they are handled and cut with a little more care. If laid at right angles with the nailings 25 per cent, is ample waste allowance, and if laid diagonally 33 1-3 per cent, is sufficient.
With carpenters' wages at 41 cents per hour, an ordinary job of square boards should cost to lay from $5 to $7 per 1000 ft. board measure. Matched boards should cost from $8 to $10 per 1000 ft. If either of the above are laid diagonally the labor would be nearly double. In case of very small jobs considerably cut up the cost would be somewhat more than the maximum price quoted above. If the building was of large, unbroken areas, the cost .should be somewhat less than the minimum prices quoted. The work upon which one is engaged must be watched to see what the costs are, and then there is established a basis upon which to work, in arriving at the probable cost of work upon which the estimate is being made.
Plank Floors
It is almost needless to say that if your floors were of plank you would proceed to obtain areas as for boards, not forgetting to multiply your net areas by the thickness of plank before adding waste. The labor per 1000 ft. board measure would be somewhat less than for 1-in. stock, as the time consumed to lay a plank of a given size, 2 in. thickness, is not double that of a board of same size.
Shingles, Clapboards and Outside Finish
When you have reached this item in the specifications and entered it upon the estimate sheet, look back under ' ' frame, ' ' Fig. 22, and see what the roof area was. Now, knowing what 1000 shingles will lay at various distances to the weather, divide the area by this amount to obtain the number of thousands. Next size up the roof and determine the number of shingles a man should lay in a day and compute from this the labor cost per 1000. With your rule scale the lengths of valleys, dormer cheeks and any other places requiring flashings, and compute the number of square feet of zinc, tin .or copper required. This settled, divide the number of square feet of flashings by the number of thousands of shingles, and thus obtain the number of feet per 1000 shingles. Having obtained all of the above, not forgetting nails, though not mentioned, tabulate, and you have the cost per 1000 laid complete, thus:
Wall shingling would be worked out in the same manner as above, the quality of the shingles and nature of the walls to a great extent affecting the price.
Clapboards
In this market clapboards are sold by the 1000 pieces, 4 ft. long. Thus, if they are laid 4 in. to the weather, one clapboard will cover 1^ sq. ft. Refer to the item of "studding and furring" on estimate sheet No. 6, Fig. 22, for the outside wall area. You will remember that in taking the wall area we did not figure out the windows and doors, so with the four elevations within easy reach scale and figure out the area of these openings. In doing* this, work in even feet, not bothering with inches. For
instance, if an opening scaled 3 ft. 6 in. x 5 ft. 9 in., calculate mentally 3 x 6 ft. = 18 sq. ft. Set this down on a scrap of paper, noting the number of such openings. Continue in this way throughout the elevations; then note any other "outs," such as the parts of wall that are covered by piazzas, wide belts, cornices, etc. Obtain and total all of above "outs" and subtract from the total Avail area, thus getting the net surface o be clapboarded. This divided by the number of feet one (or 1000) clapboards will cover, at the distance they are laid to the weather, gives the total number of clapboards.
Usually the clapboards are laid over some specified brand of sheathing paper. Proceed, as in the case of the shingles, to work out a price per 1000 clapboards laid on wall, including paper, nails, etc.
Outside Finish
Under this heading we have cornices, rakes, belt courses, balustrades, columns, pilasters, window caps, corner boards, saddle boards, water tables, brackets and so on, almost indefinitely. In some cases you can group several of these items under one subheading and figure at the same price per foot, thus saving time and condensing the matter on the estimate sheets. I find that in nearly all cases it is safer to figure the price per "unit" complete in place on the building. Let us consider each of the subdivisions of outside finish separately.
Cornices
If there are several types of cornice, differing greatly in the quantity of stock and labor to construct each, make several headings, such, for instance, as main cornice, piazza cornice, dormer
cornice or rakes. Under each heading put down the number of feet in length of the cornice, with the additional data of the number of inches of plain stock and the number of inches of moulding, size and spacing of modillions, dentils, etc. In speaking of inches above, I mean board measure inches — (1 x 1 in. x 1 ft.). It is possible that somewhere on the plans there will be
3 in. or 1 in. scale drawings of the principal parts of the outside finish, in which case you can scale quite accurately the various members of cornices, etc. In case there is nothing but the small scale drawings, you must be guided as much by judgment as by the plans in figuring out the inches of stock. Let us assume an ordinary cornice with wood gutter, brackets and other usual parts for the purpose of demonstration : Take the plain parts first, facia over gutter 4 in., facia under gutter 4 in., plancier 12 in., frieze, two members, one 8 in. and one 12 in., all J in. thick, these making a total of 40 in. of stock per running foot of cornice. Now take the mouldings : Gutter 4 in. x 5 in. = 20 in. ; gutter fillet, f in. J in. = 1 in. ; bed moulding, f in. x 3 in. = 3 in. ; frieze mouldings, one J in. x 2 in. and one 1J in. x 3 in., both equaling 8 in., these making a total of 32 in. of moulding per running foot of cornice.
Next the brackets, say 3 in. thick, 12 in. long and 8 in. deep, 18 in. on centers, with face band sawed to pattern. Now let us compile the results :
Bracket 3 x 8 x 12 in. = 2 ft. B. M. stock, -f y4 waste = Zy2 ft. stock, at 8 cents per foot, -j- planing and sawing (say 7 cents) = 27 cents each ( 18 in. o. c. — y$ bracket per foot) .18
We have now worked out everything but the labor. I find that the best way to arrive at the cost per foot for labor is to look at the elevations, pick out a stretch of cornice shown on one of them, and then try and picture yourself with a good man (carpenters usually work in pairs on such work) putting on this particular piece of cornice. In doing this don't forget that you
have got to build a stage; line, cut and fur the rafter ends, and pick out and get on to the stage the boards and mouldings. Suppose this piece of cornice to be 30 ft. long, and you conclude that with one man's help you could do all of the above preliminary work and construct the cornice in a day (8 hr.). With wages at 41 cents per hour, this means 16 hr. at 41 cents = $6.56 -^30 = $0.22 per foot. This represents what you could do yourself. Did you ever hire a man that could, or would, do as much work for you as you can do for yourself ?
The pine and mouldings have also got to be taken from a team outside the building and carried in and piled up until used. The cornice is going to require a few nails, some elastic cement, sheet lead, etc. ; hardly enough per foot of these latter to make an item under ' ' stock, ' ' which we figured out above ; at the same time, on the whole cornice, they will cost a few dollars. Considering all these things, probably 33 or 34 cents per foot will be nearer the actual cost per foot for labor and sundries than 22 cents.
I have made it a rule to increase by one-half the labor on any given piece of work after having figured out what I thought I could do it for myself, assuming this increase to cover the items of stock too trivial to figure out at so much per foot (or unit), and the lost labor that goes into every job and must be provided for: I might also add that in actual practice this rule gives nearer the correct average costs than any other that I have used.
It has taken me quite a while to tell you this, but with a little practice you can figure out running foot costs on cornices in about one-half the time you will be reading my explanations and analysis.
Belt Courses
Belt courses can be figured out in the same manner as cornices. If several of the cornices, belts, rakes, etc., are of very similar design and size, they can be grouped in measuring, and the cost on the one cornice or belt, that is the nearest to being the average, be worked out in detail and this cost used for all. In many cases the result thus obtained will be about as accurate as though each different cornice or belt had been considered separately, and varying costs been worked out and used.
Corner Boards
If corner boards are of the usual plain kind they can be taken in linear feet and the number of feet by the inches in width set down on the estimate sheet. For instance, if we had a corner made of one 5-in. and one 6-in. board, both J in. thick, and found by measuring plans that there were 124 ft. in length, we would enter same on estimate sheet as follows:
The stock you can figure readily if you know the prevailing prices, not forgetting to add to the cost per foot a sufficient amount to cover waste. The labor can be worked out the same way I worked out the building of the cornice, unless you have noted the time and figured out the cost per foot on some building, and thus have a basis to work from. The best way to measure the plans for corner boards is to have in front of you the first floor plan, and within sight and reach have one or more of the elevations. Now, look at the floor plan, and take a prominent corner, which locate on one of the two elevations upon which it will show and scale the height. Set down the result on a scrap of paper; then take the next corner (to the right or left, as you choose), locating this corner on the elevations and scale the height, setting down under the former figures. Proceed in this way around the building until you reach the corner at which you started, noting and setting down any corners showing on elevations that are not apparent on the first-floor plan, such as on overhanging second stories, dormer windows, etc., as you have the various elevations before you. Add the figures you have put down on the scrap of paper, and thus obtain the total linear feet
of corner board, which latter you enter on the estimate sheet with the total width, thickness and kind of lumber. Having done this, proceed to the next item, leaving the figuring out of the cost until through with the surveying of plan. The above explanation for surveying plans for corner boards would apply where a building was somewhat irregular in plan and with several different lengths of corners. By checking from the floor plan you avoid the possibility of missing any corner and of getting any corner twice. As each complete corner appears on two elevations, there is a probability of the latter error occurring if floor plan is not referred to. Of course, if the building is perfectly plain and all corners run to the main cornice, the latter being level all around the structure, you need only to glance at any floor plan; count the corners; lay your rule on any elevation, scale the height ; multiply the height by the number of corners, mentally or otherwise, and thus obtain total linear feet.
Saddle Boards
Saddles can be measured either on the roof plan, if there is one, upon which they all show, or from the several elevations. Some care must be used in working from elevations not to get the same stretch of saddle measured twice, as each run of saddle board will show on two elevations. Enter the total linear feet, width and other particulars on the estimate sheet in same manner as corner boards.
Water Table
This can be more conveniently measured on the first floor plan than from the elevations. In measuring begin at some one corner and work around the outline of the building until you arrive at the starting point, setting down on a scrap of paper each length as obtained and adding for the total. The total number of feet, with the particulars (inches of plain stock and molding), are then carried to the estimate sheet.
In ordinary frame structures the corner boards, saddle boards and water table are usually of dimensions sufficiently alike to permit of their being all surveyed together and the cost carried out at one price per linear foot
Window Caps
Where windows have molded caps there is usually some one of the cornices that is of about the same section, and you will find that you can simplify matters somewhat by measuring caps with such a cornice. In measuring a cap I always allow 2 ft. extra length over face measurement to cover returns.
Piazza Facia
The plain board or facia that goes over the sill of the piazza I usually make a separate item, and include with it the risers and face stringers of all outside steps and the base board of lattice work. Carry to the estimate sheet the total running feet and make note of the average width and thickness. Most of the measurements for all above piazza and step parts are readily obtained from the first floor plan, but if you choose the elevations may be used. In any case, you must refer to the elevations for the widths.
Piazza Floors and Steps
These are simple matters of areas and should be taken from the floor plans. I usually take both under one heading, measuring the steps double, as the treads are usually of 1£ or 1^ in. stock, and the cost of labor per "square" or square foot is greater than for the piazza flooring. Of course, the result can be worked out more minutely if you make two separate items; but the step area is usually such a small part of the total area of piazzas and steps that the costs carried out will be but slightly affected if you consider them jointly.
Columns and Pilasters
If there are piazza columns and pilasters make a note on the estimate sheet of the number, size and description of each kind. If you are unable to figure out costs for these parts delivered at the building, you can confer with a mill man and obtain prices from him. To the price delivered should be added the cost of the labor handling and setting, thus carrying out the cost for them set complete in the building. In determining the labor cost per column or pilaster for handling and setting, apply the rule I have given for figuring labor on cornices. This rule is
readily applicable to any item of outside or inside finish, and in the absence of statistics of costs obtained from actual erection of similar parts in structures you have built, I know of no other way of arriving at the probable cost. Many men take other men 's word for the cost of labor per given unit, but so few men make any attempt to prove their opinions in such things that you will do better to rely upon your own judgment.
Balustrades.
Balustrades can be best figured by the linear foot erected. The quantity is most readily obtained from the floor plans, but you must refer to the elevations for the style of rails and balusters. Sometimes in the absence of elevations a full description of balustrades will be given in the specifications. In analyzing a foot in length of balustrade you have 1-0 of top rail of specified section, 1-0 of bottom rail ditto, and as many balusters of the required size and spacing as it takes to make 1 ft. 0 in. The labor you can determine by the rule I have already given. As all ordinary sizes and shapes of rails and balusters are sold at standard prices in each locality, you should experience no difficulty in making a very close estimate of the probable cost per foot.
If the parts are of special design, you must exercise your judgment in working out costs, or refer the particulars to your mill man and get his prices for material delivered, to which must be added the labor. Where small posts or buttresses occur in balustrades count same and make a price each, installed. As an example of entering columns, posts and balustrades on the estimate sheet see Fig. 22.
Lattice.
I find the most convenient way to figure lattice is by the square toot. The quantity you will have to take from the elevations, and in measuring for same remember that the border boards cover up, as a rule, almost their entire widths of lattice. The spruce framing necessary to fur for lattice work is in most cases so small a factor that it need not be considered. If, however, it should appear to you that enough furring will be required to make it worth while to take note of it, take a typical panel of
lattice, work out the number of feet board measure of furring and studding necessary for this particular panel, and then divide the quantity by the number of square feet of lattice in the panel. This will give you the quantity of furring per square foot of lattice, and in making your cost it can be put in at its value.
I don't know as it is necessary to further enumerate outside finish, as I have given enough examples to enable you to subdivide and work out costs on the numerous items under this heading. The nature of the plan's and details for these parts will have to be the determining factors in the number of subheadings into which you will divide the work for convenience in measuring and analyzing costs. As, in the general run of good work nowadays, no two jobs will be exactly alike, judgment will be a large factor in making the unit prices.
Windows, Doors, Inside Finish and Floors
Ordinarily the windows of a building are quite uniform in size and detail. This is especially true if we leave out of consideration the basement or cellar windows. In figuring I make one typical window the "unit" upon which to carry out the estimated cost of the windows of a structure. In figuring the cost of a window include the frame, sashes, weights, cord, hardware, blinds and trimmings, stool, apron, casings, edge casings, stopbeads and rough grounds ; also in working out the cost of labor per window consider the labor on all of the above enumerated parts, together with the time involved in taking these materials off the teams and carrying them into the building, and the handling and distributing to the various rooms until installed. By taking a window which seems to be a fair average in size and detail and carefully working out the cost on all the parts and operations— as above noted— and using the cost thus obtained for all windows, the resulting figures will be, in nearly all cases, as accurate as though you had made 15 or 20 different prices for as many kinds and* sizes of windows. However, if there happens to be several very large and out of the ordinary windows, such, for instance, as a large tripple, with pilaster casings, semi-circular transom, leaded or plate glass, etc., it is wise to leave them out of the general enumeration and figure the cost separately. Also if there are a number of very simple windows, such as small cellar sashes with plank frames and no inside finish, make them a separate item. Thus in the case of almost any building an accurate result can be obtained by making no more than three items of windows.
The costs of stock-size and ordinary detail windows, frames and blinds are standard in every locality and can be readily obtained if you do not already know them. You should also have a common and plate glass price list at hand and keep posted on the discounts ; these vary from time to time, but if you are buying much glass you will receive the notice of any change in dis-
counts from your local dealer. The members making up the finish of a window are easily figured at moulding prices, which are usually for a certain amount per square inch of section, per foot of length.
As an example we will work out the cost of an average window, such as would be found in the hypothetical building of which we are making a survey and estimate :
Having thus worked out a cost on, an average window, carry out the cost for all windows as shown on Fig. 33, by multiplying by the whole number. You will find that the result of using this average price will, in most cases, give a probable cost as accurate as you would obtain if you made a dozen different kinds of windows and used a separate cost on each. By including all windows in the count, calling a mullion two, and a triple three windows, etc., and not excepting the simple cellar and attic windows, you save yourself a lot of time, and wearisome figuring. There are almost invariably several windows in a building that are considerably more expensive than the average, and the difference in cost between the cellar and other very simple windows and the average window upon which your price is based will usually compensate for the former.
All I have said about windows will apply to doors, except that in many buildings it may be policy to separate doors into two or more classes. I advise that this be done in the case of doors,
because there are usually but two or three classes and sizes of doors in a building, and the same structure would have perhaps 20 kinds and sizes of windows. Thus subdividing the doors will not complicate matters or seriously interfere with speed in figuring. Take one door of each class and dissect and analyze it in the same way I did the windows. Begin Avith the grounding of rough opening and figure everything to make a complete door and trimmings installed in the building.
Base and Mouldings
Base and moulding should always be figured together and in running feet. In making a price per foot include grounds, base and moulding, and labor for all of these items of stock; not forgetting in determining the labor item to take into account the miscellaneous handling of the stock from a team into the building and its distribution to the various parts of the structure preparatory to actual installation. If there are several kinds of base, measure each kind and work out the cost separately. In measuring the plan I find the best way to proceed is as follows: Assume part of the building to have 8-in. base and IJ-in. moulding of white wood and the balance 9-in. base and 2-in. moulding of quartered oak. Take a piece of paper and at top of same make memos. as follows :
102 .. 112
Now begin with the first floor plan and take a room in one corner of the plan: Scale one way, say 12 ft., double for the two sides of the room and set down 24 ft. ; then scale room the other way, double and set down; note the doors, say two, each eliminating about 3 ft. of base; under "outs" set down 6 ft. If
there is a closet to this room, take the base in this next and enter measurements under the proper heading of dimensions and kind of wood. Continue your measurements throughout the entire floor, taking the rooms in the order that the plan suggests to you as being least apt to lead to confusion.
Having completed the first floor, take the second in the same way, also the third, etc., until the whole building is measured. Then, by adding up the gross measurements and "outs" separately, and deducting the latter from the former, you have the net running feet of each kind. I have carried out a few measurements under the headings and performed the subtraction of "outs" to show how it is done. The net amounts thus obtained can now be carried to the estimate sheet and the price per foot and total costs be figured after you are through with the plan. Sometimes a building is laid out so nearly alike on each floor that the result will be sufficiently accurate if a typical floor is measured and the quantity thus obtained is multiplied by the number of floors.
Chair Rails, Etc.
Chair rails, picture moulding, and all similar parts of inside finish can be measured in the way demonstrated above for base and mouldings, the total running feet in each case being carried to the estimate sheet. Where grounds are required, figure both stock and labor in making the price per linear foot installed.
Clothes Closets
Having, in surveying the base, taken care of the closet base, and in making price for doors included all finish and labor for same, all that is left for us to figure in an ordinary clothes closet are the hook cleats, hooks and shelf.
Refer to the floor plans and count the closets, putting down on estimate sheet, Fig. 33, the number. With plans still before you pick out a closet that represents about the average size and on the figuring pad put down the number of feet of hook cleat, length and width of shelf and number of hooks as follows :
Having done this, figure out the cost of these materials and determine the length of time that will probably be required by a carpenter to install same and add for a total cost per closet. It may happen that several closets included in the count of 19, as set down on estimate sheet, have a case of drawers in addition to the cleats, hooks and shelf. In this case enter on estimate
sheet, Fig. 33, the number, and work out the price, complete, installed. If you are not familiar with mill work and cannot reason out a price for yourself, put down height, width, depth and number of drawers and kind of wood, and after you are
and then carry out the cost.
In the same manner all special closets, such as for china and linen, pantries and pot closets, or any small room with out-ofthe-ordinary finish, may be analyzed and a cost worked out to suit the conditions found.
Stairs are now usually built by men who do nothing else, and bids for the stair work of a building can readily be obtained at short notice. However, I think it is better to keep posted as to the cost of rails, balusters, newels and similar parts of stairs, and to take the trouble to see how long a man is occupied in erecting and finishing different staircases on the work, and thus prepare yourself to make sufficiently accurate costs for use in the estimates. There is such a decided similarity in stairs found in ordinary apartment houses and dwellings that in a short time you get well enough acquainted with the costs per flight to look at a flight on the plan and sections, read the specifications covering it and make a price "off the reel" to use a slang phrase, as close as you could get if you figured for half an hour or called in a stair builder. Of course you cannot apply any such snap judgment to complicated and out-of-the-ordinary flights, and on such as these it may be wise to call up your mill man or stairbuilder and ask some questions and prices before making out a cost yourself. And so I might go on indefinitely with inside finish, but I think I have given enough examples to "blaze the way" and your own judgment will carry you through any other items under this head that you will encounter. If you do not always feel secure in your own judgment, list the items and write down brief description ; then go and talk it over with the mill man. Then, having made a price, if you obtain the job, see how your prices work out, and thus check and correct your judgment. In the long run it is much more satisfactory and safer to figure this way than it is to take a lump sum bid from a mill man for all finishing materials and to try and lump the labor of installing them.
You have noticed that under the various subdivisions of inside finish I include "grounds" in working out a price. This item usually appears in the specifications after "studding and fur-
ring," but if you were to take up the surveying of the quantity at that time you would have to go all through the plans and spend perhaps 15 minutes' time. By ignoring it then, and taking it with "doors," "base," "chair rails," etc., your survey serves you a double purpose, and it is just as easy to include the cost of grounds and labor in figuring a door, or a foot of base, as not to, and results are more accurate. Upper floors are best figured by the "square" (100 sq. ft.) laid and smoothed complete. If there are several different kinds of woods used, some having more labor expended upon them, such as in laying borders, high class smoothing, etc., each kind should be surveyed separately. In cases of this kind the best method in which to make the survey is to take the dimensions of each room or compartment separately, setting same down on a scrap of paper under the head of the kind called for. For example, assume that there are some quartered oak floors, 2J in. wide, matched, and that the rooms where same occur all have borders 2 ft. wide; other rooms have Rift Georgia hard pine, 2£ in. wide, matched, no borders, and still more rooms with slash North Carolina pine, 4 to 6 in. wide and j Hatched ; also that all floors are laid over heavy sheathing paper, and that the oak and Georgia pine floors are to be protected as soon as completed by covering them all over with good serviceable paper, which is to be renewed as often as necessary to keep these floors in condition until building is turned over to the painter. Then proceed as follows : On your figuring pad make the headings thus : • " Oak, " " Geo. " " N. C. P. " Take the first floor plan and begin in one corner, scaling dimensions of this room, which we will call "Geo.," and enter dimensions under this heading. If this room was 14 ft. 6 in. x 16 ft. it would go down on the figuring pad thus :
14 ft. 6 in. x 16 ft.
Take the next room or closet, scale, and enter dimensions where they belong, proceeding in this way throughout the entire floor, choosing a course from room to room that suggests itself as being least apt to lead to confusion. After all of the floors in the building have been taken in this way, a few minutes' figuring will give the number of squares of each kind, and these totals can be carried to the estimate sheet, Fig.
34, with brief descriptions, and a cost per square for each worked out later. In taking off the floors in this manner there will probably be no "outs" worth taking into account. If there are any of consequence, note of their dimensions should be taken at the time of scaling the compartment in which they occur, and they should be entered on the figuring pad under the head of "outs" and in a parallel column with the particular kind of floor you are surveying. The results obtained by such a survey as just described will be very accurate, if any care is taken in scaling dimensions. To simplify the figuring as much as consistent with reasonable accuracy, work in feet and half feet only. Thus, if a room scaled 14 ft. 8 in. one way, call it 14 ft. 6 in. ; or, if 14 ft. 10 in., call it 15 ft. By the time you have been through the whole plan the differences thus made will be pretty well averaged.
If there is only one kind of flooring in the building, or possibly a very little of a second kind, the survey may be made much quicker and with sufficient accuracy by proceeding as follows : Assume a rectangular plan, say, 60 x 80 ft. inside of walls, cut by partitions into numerous rooms or offices, such as would be the case in an apartment block or office building. Look at the floor plan and see about how many partitions there are running substantially parallel with each dimension of the building and practically continuous. Say that there are five partitions more or less continuous the 60-ft. way and four the 80-ft. way. The average partition by the time it is plastered and based, will be near enough to 6 in. to call it so. Then cut the 80-ft. dimension five times 6 in. or 2J ft., making it 77^ ft., and the 60-ft. dimensions four times 6 in., or 2 ft., making 58 ft. Then the area to have an upper floor will be 58 ft. by 77 ft. 6 in., less what "outs," such as stairways, large chimneys, small areas of tile in toilet rooms, etc., there may be. These figured out, and a net area or number of squares is obtained for one floor. If the succeeding floors are of nearly the same area, multiply by the number of stories in the building. Now, if there are a few squares or some other kind of flooring, survey same, room by room, figure a total and subtract from the grand total for the whole building. By this method the floors of a very large building can be surveyed in several minutes. If you are hurried with your plan and must give it up to
Now, as there will be some little handling of the flooring stock and moving of other stock and cleaning up to make room for the floor layers, I should figure $26 per square ; thus in the estimate sheet shown in Fig. 34 we carry out the cost of the 21 squares at this price. By analyzing as above, work out the cost, installed complete, of any kind of flooring. In the locality of Boston carpenters never lay floors except small quantities met with in jobbing. We let the labor of laying to a contracting floor layer at so much per square, or in some cases for a lump sum for the entire building. If such is the case in your community and you are not posted on costs, you should become acquainted with the standard prices per square charged for the various kinds of work.
In every building there are miscellaneous special items or parts that must be listed and probable costs be computed. Amon<r these will be such items as store fronts, bulk heads, cabinets of various sorts for gas or electric meters, standards for plumbing fixtures and boards or panel work to cover pipe slots, scuttle and ladder to roof, cellar and coal bin partitions, etc. As you come to any such item in the specifications proceed to list the materials and probable labor on the estimate sheet. Many of these items are so briefly explained in specifications, and so meagerly shown on plans— if shown at all— that their cost is pure conjecture. In making a price in such cases you will of necessity have to be governed by local customs, supplemented by your familiarity with the architects' practice.
Plastering
If the plastering in a building is not of a complicated character, it may be easily and accurately figured by any one who can survey the quantities, as the prices per yard for the several kinds of work are standard in every locality. Where there are cornices, panels, enriched mouldings, columns and pilasters with capitals, and all similar parts out of the ordinary, the work will have to be figured by an expert plasterer. For purpose of illustrating methods for surveying quantities, we will assume that the building in hand has no plastering out of the ordinary. Say, for instance, that the boiler room ceiling is two-coat work on wire lathing, and that several sets of steel beams and the cast iron columns are wrapped with wire lathing and plastered two heavy coats for the purpose of fireproofing them; that the balance of the work is two coats— brown mortar, and sand and lime-putty skimming— on IJ-in. spruce lath. Included in the last kind is the cellar ceiling except boiler room.
Take the framing plan that shows location and length of the steel beams; scale the length and note the size and number of beams making up the sets. Assume a set of three 15-in. 42-lb. beams, carrying a 20-in. brick wall over 17-f t. openings ; the girt of this set will be 15 in. plus 15 in. plus 19 in., these figures being the dimensions of the two sides and soffit of the set to be wired and plastered; thus the area to plaster is 4 ft. 1 in. by 17 ft. This is so near to 4 x 17 ft. that we put it down so. Now proceed to the other sets of beams, setting down on the figuring pad the several dimensions as for the first set. Having taken all beams, lay aside framing plans and take regular floor plans. Look up the columns next. Assuming the number, length and size of columns shown on estimate sheet No. 5 in Fig. 21, under the head
Of course, you know without my telling you that the circumference of a circle is slightly over three times its diameter— to be exact, 3.1416, or three and one-seventh times. For purposes of estimating such items as we are now considering, three times the diameter is sufficiently correct, as an inch or two, more or less, in the circumference of a column will make so slight a difference in materials and no difference in labor, that it is not worth while to take it into account. Now put all of your dimensions into square feet, and by dividing by nine obtain the square yards, or the unit of measure by which all ordinary plastering is figured. The number of yards thus obtained carry to the estimate sheet and enter with brief description.
2 ft. 6 in. by 14 ft. x 5 times:
these last two dimensions, with the dimension of 4 x 17 ft. assumed above, being for the three items of sets and single beams listed under the head of "Steel Work" on estimate sheet No. 4, shown in Fig. 20.
Next take the boiler room ceiling, ceiling perhaps 17 x 24 ft., which makes practically 45 sq. yd. Enter this on estimate sheet with description. This brings us down to the balance of the building, which is all one kind of work. To be real accurate in obtaining this part of the survey, take the dimensions of ceiling and walls of each room separately, room by room and floor by floor, to the end, setting down dimensions on your figuring pad and computing into feet and yards, which latter quantity, after subtracting the "outs," we carry to estimate sheet.
scale room both ways and put down ceiling dimension thus: 14 x 16 ft. ; then looking at above dimensions compute mentally the perimeter, or outline, of room thus : twice 14 is 28, plus twice 16, which is 32, makes 60 ft. ; then under ceiling dimensions enter 9 x 60 ft. for wall dimensions.
Custom Avith regard to "outs" varies with locality, but in Boston and vicinity plasterers in figuring subtract one-half of the "outs," unless they are of such size as to amount to nearly the whole end of a room, or are of similar proportions. In a building such as the one in hand the only outs will be doors and windows; the average rough door opening will be about 3x7 ft, or 21 sq. ft. one side, or 42 sq. ft. two sides ; the average window will be about 3x5 ft. or 15 sq. ft. In the buildings of this class there are usually about the same number each of doors and windows. Now with the "outs" for doors and windows as assumed above we have 57 sq. ft., total of a door opening (two sides) and a window (one side). This 57 sq. ft. is practically 9 sq. yds., or an average of 3 sq. yds. per door side, or per window side. Then to allow out of the total survey the customary amount, we halve the 3 sq. yds., giving us 1J sq. yds. per door, or per window, side.
Having obtained the quantity of plastering by measuring each room and computing the dimensions thus obtained into square feet and square yards, no attention, meamvhile, having been paid to doors and windows, we next count the number of doors and multiply by two for the number of "sides," and to this add the number of windows. Thus we obtain the number of "sides" out. Say, for example, that there are 44 doors, two of which are in the outer wall; these would make 86 "sides"; also that there are 42 windows in outside walls that come in plastered compartments ; these make 42 more "sides." Thus we have a total of 128 "sides" to allow out at 1J sq. yds. each, or 192 sq. yds. This quantity we subtract from the whole survey and obtain the number of yards upon which to compute the cost. If there were "outs" other than for doors and windows their dimensions should be set down on figuring pad under this head ("outs") at time of making the room by room survey, and their resulting area in square feet be deducted from the total square feet before reducing to square vards,
Surveying Plastering
All that I have said before in these articles under other heads in regard to figuring in feet and half feet should be applied in surveying plastering. Now that I have shown you how to make an accurate survey of the plastering, which you must admit will
give you the correct result if the arithmetical operations are correctly performed, I will give you another way to survey the building for plastering that will be nearly as accurate, that you can perform in one-eighth of the time consumed by the first-
method ; neither will it be necessary for you to look at the plan. In making these last two statements I am assuming that you have listed the quantities and areas of materials in the building in the same general way that we have surveyed our hypothetical structure. Taking the building in hand, with materials shown on estimate sheets Nos. 1 to 8, inclusive, and the same plastering specification assumed for the first survey, proceed as follows: Take the fireproofing of beams and columns first. Refer to estimate sheet No. 4, in Fig. 20. Having listed the beams and sets of beams there scheduled under the head of "Steel Work," you will recall, upon looking at same, their location in the building, and how much of them will be exposed and thus require fireproofing. That set of three 15-in. 42-lb. beams 19 ft. 6 in. long you know must be over an opening about 17 ft. wide, because such a set should have bearings on the walls of 14 in. or 15 in. You also know that if bolted close together they would measure about 18 in. from outside to outside of flanges, because the flange on a 15-in. beam is at least 5J in. So you comprehend in a fraction of the time that I consume in telling you that this set of beams require wiring and plastering of the following dimensions : 15 in. + 15 in. -f- 18 in. = 48 in. = 4 ft. x 17 ft. long, and you enter these figures on the pad. In this manner you go through the list of steel. Now take estimate sheet No. 5, in Fig. 21, and refer to the list of cast iron, picking out the parts requiring fireproofing, which in this case are the columns. The dimensions for plastering you can read at a glance and immediately enter on the figuring pad, under those for steel. Both items of materials requiring fireproofing having been looked through and the dimensions of quantities obtained, proceed to compute into square yards and enter the number of yards and brief description on estimate sheet No. 8, in Fig. 34, under the head of ''Plastering." Now go right through the estimate sheets until you come to the first item that gives you the area of some plastered portion of the building. Begin with the sheet No. 1, in Fig. 17. No dimensions there that indicate plastering. Sheet No. 2 ; in Fig. 18, an item of 492 sq. yds. of concrete floor is shown. We know that the ceiling is of the same size as the floor, so we have here, all figured into square yards, the area of plastering
for basement ceiling. Remembering while on this item that the boiler room ceiling was wire lathing, you probably recall the approximate size of same. If you do not, a reference to sheet No. 1, under the head of "Excavation," may show you the size of the room, measured outside of surrounding walls. You recall that the boiler room was%about 3 ft. deeper than the rest of the cellar, and immediately identify the second dimension under "Excavation" as the size of boiler room, measured outside of the walls and their footings ; so you shrink the figures about 2 ft. each way and call the size of the boiler room 16 x 22 ft. 6 in. Thus you have the information you were looking for without recourse to the plans, and you can compute it into square yards and carry the number of same, with particulars, to estimate sheet No. 8 in Fig. 34, under "Plastering."
As you have taken the size of the whole basement ceiling from the number of square yards of concrete scheduled, which in this case we are assuming covers the entire floor, the 40 sq. yds. determined upon as the area of the boiler room ceiling must be subtracted from the total of 492 sq. yds., leaving 452 sq. yds. of the two coat on wood lath plastering; this you enter up in the corner of the figuring pad and again refer to estimate sheets for more information as to plastered areas.
On estimate sheet No. 6, in Fig. 22 under head of "studding and furring," we find listed the partition areas. To use these areas for plastering we must double them, for in surveying partitions for studding we measure one side only, whereas they must be plastered both sides; so we take the first three items— 2364, 1724, 944— which are square feet of partitions, add them and double them, making 9864 sq. ft. of plastering. This quantity reduced to square yards makes 1096. This we carry to the corner of the figuring pad under the 452 sq. yds. previously set down there.
Looking still further into the schedule of studding and furring, we recognize in the item of 11,232 sq. ft. of J in. x 2 in. furring, all of our ceilings— basement excepted— which was lathed directly on the joists, and in the item of 3104 sq. ft. of J in. x 3 in., the furring of the exterior brick walls, where plastered. Then the total of these two divided by 9, which makes
1593, are the number of square yards of plastering in ceilings and outside walls. This quantity set down on figuring pad under the other two items, and the three added, gives us a total of 3141 sq. yds.
Next we must find the "outs," so we look along through the estimate sheets until we come to the doors and windows on sheet No. 7, in Fig. 33. Here we find 42 windows, 4 entrance and vestibule doors and 40 inside doors. Assuming that there are two entrance doors, which would be in outside walls and two vestibule doors, which would come in partitions, we figure up the number of sides as follows :
Total 128 sides
Allowing out 1J sq. yds. per side, we have 192 sq. yds. to deduct from our total yards, which was 3141, making 2949 sq. yds. This quantity we carry to estimate sheet 8, in Fig. 34, under head of * * Plastering, ' ' and later carry out a price on same. Thus you see it is possible to make a reasonably accurate estimate of plastering from data taken from the estimate sheets, if quantities of materials have been entered as I have suggested.
Under the head of "Plastering" the specifications often call for the temporary closing of the building, also make provision for drying the plaster. The cost of these items is largely a matter of judgment, especially as regards drying. Temporary closing is usually a matter of supplying and installing screens, of cotton cloth on frames of furring, in all window openings, and the making and hanging of batten doors of coarse materials to exterior door openings. Knowing the number and approximate size of windows and outside door openings, you should be able to analyze and determine the cost of same, without any special instructions. To determine the cost of drying plastering you must take into account the size of the job, the length of time required to perform same, the price of coal, the method of drying,
whether with the regularly installed heating apparatus or with salamanders, and the probable amount of attendance required. Some plasterers of my acquaintance have reduced the cost of drying to a price per yard (of plastering) basis by keeping a careful account of the total cost of drying on a number of jobs, finding the cost per yard on each job and thus obtaining an average. One plastering contractor of large experience in Boston is figuring the cost of drying at 6 cents per yard for work done in cold weather. Of course work done in late spring, summer and early fall can be dried out for less per yard than this, as Nature lends her assistance to the task.
I have discussed the subject of estimating painting with a great many contracting painters, and I find there is a great variation in methods of arriving at probable costs. In one particular only do I find them practically unanimous, and that is that the unit of measure is a square yard. The cost per square yard is determined by the number of coats to be applied. In Boston the generally accepted price per coat per square yard is eight cents ($.08). This of course is for plain work : either painting, filling, shellacing, varnishing, staining, etc. Washing old work preparatory to painting and rubbing down between coats, if thoroughly done in each case, are each usually considered to be worth as much as one coat of paint, thus being worth 8 cents per yard.
Such work as elaborate cornices and other complicated outside finish can hardly be considered on the above basis, and I find that the painters when estimating compensate for extra work at these points by doubling, tripling, etc., the yards of surface, being governed in doing so wholly by their judgment. Thus, if a building wall was 20 ft. high from underpinning to the first member of •the cornice, and the cornice was quite elaborate and had a profile of about 4 ft., the painter, instead of figuring the wall 24 ft. high, would double the 4 ft., to compensate for the extra labor involved and figure wall 28 ft. high. He would then multiply by the distance around the structure and reduce to square yards and set the price according to the number of coats to be applied. If this cornice was painted in several colors, he would probably triple or quadruple the 4 ft., according to his judgment. The balustrades, columns, belts, etc., would be treated in a similar manner to the cornice, their complexity and the number of colors being the governing factors as to the amount the actual surface should be increased to compensate for increased labor required.
PAINTING 117
is to increase the height one eighth, to cover the butts of the clapboards. If the wall is of shingles (painted, not stained), or of brick, the height is increased one-fourth. The reason for this larger increase in the case of shingles or brick is because of the fact that walls of these materials are quite rough, and much more brush work, as well as more paint, is required to coat them.
In measuring a wall surface no attention is paid to windows, the wall being considered solid. The windows are then measured over-all, outside of casings, and this surface doubled. Thus a window that measured 4 x 6 ft. out to out of casings would be worked out as follows: (4x6 ft. x 2) -j- 9 = 5^ sq. yd., or practically 5 sq. yd. As it is almost the invariable custom to draw the sash in a different color from the casings, stool and cap, the doubling of the surface is to compensate for extra time involved in cutting in the two colors. You can readily see that if the sash and casings were all one color that a painter could paint both frame and sash in about the same time that it would require to paint each if colors were different. If the windows have blinds they would be figured from $.75 to $1 each pair, according to size and number of coats. Four- fold blinds for one window opening would be counted as two pairs. Except in the case of very large or very small blinds, the size makes so little difference in labor, and still less in quantity of paint, that it is not customary or necessary to take the size into account.
In measuring shingled walls or roofs that are stained (brush coated, not dipped) the surface would be taken as explained above for painting. But as the cost of stain necessary to coat a given surface, also the labor of applying it, is somewhat less than paint, the cost per yard, per coat, is figured less. The customary price per yard for stain as above is about 7 cents per coat.
In figuring plastered walls which are painted, measure the total height from floor to ceiling, not taking out for base and moulding, chair rail and picture moulding. The extra labor cutting up to these parts as a rule involves more time than the painting of the surface under them would consume.
In measuring walls no attention is paid to windows or doors.
The same rule used for measuring the outside of the windows is applied to the inside of them and also to doors. As doors and windows are generally of about the same size in most buildings many painters in surveying plans, call each side of a window or door 5 yd., and each side of a door with transom 6 yd. of surface, price per yard of course being based on the number of coats.
Either a base and moulding, chair rail or picture moulding is figured 1 ft. wide, the running feet being surveyed and then reduced to square yards. A sheathed dado would be figured into actual surface, the length being multiplied by the height and the square feet thus obtained reduced to yards. In the case of ordinary paneled dado the height would be figured double ; and if there were raised panels, carved mouldings, etc., triple or quadruple or even more as judgment dictated.
Pantries, china closets, linen closets, store cases, counters, etc., can usually be worked out in surface yards, following the rule for increasing surface as given above for dado work.
are wholly matters of judgment rather than yards of surface.
In figuring tinting of walls and ceilings with water colors, cold water paint, or the various prepared substances of a similar nature, proceed to survey surfaces as above outlined for plastered walls. If plastering is first sized this is taken into account in making the price per yard. Sizing for this kind of work is worth less per yard than for lead and oil painted work, as it is mixed and applied thinner, thus taking less stock and labor. Ceilings and walls of stores, offices or other similar apartments, are usually conceded to be worth from 8 to 10 cents per yard for one coat size and one coat water color. Rooms in dwellings are usually figured somewhat more, running from 10 to 20 cents per yard.
If stories are of unusual height, thus requiring more staging and climbing, the costs or areas must be increased to compensate for the extra labor required. The costs for all substances similar to water colors are about the same as. above quoted.
The total cost of any job of painting divides about as follows: 75 per cent, labor and 25 per cent, stock. So you can see that the estimating of costs for this work is more a matter of judgment than actual surface to be coated. By a reasonably close adherence to the above rules one should be able to make a sufficiently accurate estimate of the cost of a job of painting to use in making bids upon a whole structure. When the work is quite complicated you will do better to call in a painter and get bona fide bids.
The plumbing of most buildings is of such a character that in order to get anything like an accurate cost one must call in a contracting plumber and get a figure; or, better still, call in several plumbers, and use the bid of the one who submits the lowest price.
There will be times, however, when the plumbing is quite simple, and so nearly like jobs that you have done in the number, arrangement and quality of fixtures, that you can judge quite closely of the cost. When such is the case and you feel that the job you are figuring is not going to be figured down to the danger point by your competitors, it may be safe for you to use your judgment and make a price yourself. In order to school your judgment on plumbing costs it is a good plan to count, and make note of, the number of fixtures in the building, and then when you have received your bids from plumbers and chosen the one you will use in making up your figure, you can work out the cost per fixture for this job. If this is done on every job you figure or do you will soon have quite a line on the plumbing costs, and as above suggested there will be jobs figuring from time to time that will compare favorably with these first mentioned ones, and then you can make a reasonably close and safe figure yourself. In enumerating fixtures, count one for each of the following : watercloset, bathtub, lavatory, sink, kitchen boiler, set of trays, each urinal in a range of urinals, large house tank, large brick set grease trap, etc.
Gas Piping
In the average run of work the cost per outlet is standard in each locality. Knowing the standard price per outlet, figuring the cost of installing the system of piping then becomes simply a matter of counting the outlets and multiplying by the cost in your locality. Your own judgment will tell you that if the outlets are very much spread out more piping must be run in order
to install the system than if of about the average distance apart and arrangement. This state of affairs will of course increase the price per outlet. The same rule carried to the opposite extreme will reverse the matter, making less piping to install a given number of outlets, thus making cost per outlet less.
By counting and entering on the estimate sheet the number of outlets, and then looking over the arrangement of them on the plans, you can readily judge about what proportion to increase or decrease your standard "outlet price" for the job in hand. As the gas-piping is usually such a very small percentage of the whole work a little difference in cost, either way, will have but a very slight effect upon your total figure for the work. When you actually let the piping job take note of the price per outlet and thus check and cultivate your judgment.
Electric Light Wiring
Practically all that I have said in regard to gas piping applies to electric light wiring. There are two classes of light wiring: one called conduit work, which consists of a system of tubes or pipes similar to gas piping, running to all outlets and switches and arranged in such a way that all circuits can be made and into which the wires are drawn by means of a long flexible piece of steel called a snake.
The other system is called knob and tube work, the wires being run on earthenware knobs, and where passing through joists or studs, through short sections of earthenware tubes.
For each class of wiring there is about a standard price per outlet for the general run of work, and by posting yourself on these prices you can make fairly close estimates. If the work is of a complicated character it will be wiser and safer to have subbids from electrical contractors, using in your estimate the lowest figure.
If, when estimating a job, you will count the outlets and then work out the price per outlet from your lowest sub-bid, you can obtain information in regard to costs for future use.
unless the job in hand compares in size, system and general Conditions for performing work, with some plant you have recently had installed, it is safer to call a heating contractor and have sub-bids for the work, using, in making up your figures, the lowest bid received, if from responsible parties. There will be times, however, when the plant is so decidedly like something you have done before that you can note any minor changes that would increase or decrease the cost, and use your judgment as to the probable change in price on account of the differences.
Most contracts made with general contractors to-day are exclusive of plumbing, heating and electric work, so you will seldom be called upon to figure these parts of a building. Notwithstanding this you will be wise to make notes as to the quantity and quality of each of the parts of the work and if possible find out what they are costing. The information thus obtained will be of great help to you in judging costs or letting contracts^ for these parts of a building.
Having now considered all of the various items going to make up the average building we next take up matters that are not often mentioned in the specifications, but, nevertheless, just as necessary to consider, as they add to the cost of the whole work.
Miscellaneous Expenses, Lockers, Profits, Etc.
In the very first part of this article I suggested visiting the site for the purpose of seeing under what conditions you would be compelled to work. Having done this you found out the cost of making a round trip, also cost of board and lodging in the vicinity and other similar details. Now make up your mind how long the work will take; how many times you or your superintendent will probably have to visit the job while the work is being put through; how many mechanics you will send whose fare and board you will have to pay, and any other minor items of cost of a similar nature you will be put to on account of the work. Compute these estimated costs and enter upon your estimate sheet under the head of expense.
Watchman
If you are going to employ a watchman figure up his wages for the length of time you expect to keep him, making this an item on estimate sheet, as shown in Fig. 35.
Sundry Expenses
On a job of any size there are a number of little items of cost, each in itself quite small, but in the aggregate sometimes totaling quite a sum. Among them are such items as follows: building plan and tool lockers and sheds to protect materials; fences, walks or barricades over dangerous places to provide for public travel, or your own convenience in handling the work or protecting your help ; cleaning up and carting away debris, resulting from building operations, from time to time ; protection of trees, shrubbery, lawns, walks, etc. ; sanitary provision for the workmen; water for building purposes; final cleaning of building, washing windows, etc. ; telephone connections ; insurance and bond; and so on indefinitely. On a building we recently constructed, costing about $160,000, I found upon tabulating the
cost of the above items that they amounted to nearly 2 per cent, of the total cost of the work. Thus you see that it is wise to consider these items collectively, or in some cases individually, en-
tering upon your estimate sheet their probable cost. In determining this amount you will have to be governed largely by your judgment, based on previous experience. By taking these items one by one and judging the cost of each, then adding for a total, you will be apt to arrive at a probable cost much more accurately than by lumping them. Keep the cost of these items
Total Cost
Now, having considered all the items going to make up the completed structure found in the specifications and some that are not mentioned, but just as necessary to a complete execution of the work within the meaning of the said specifications, plans and contract, we now bring the total of each sheet to the last one, setting them down in their order, and adding for the total estimated cost. This we find to be $30,684.12.
Profit
If you expect to remain long in business you must have profits. Just how much this should be, you are your own best judge. If you are doing business in a small way, are your own foreman and have no office to maintain, bookkeeper to pay, or other kindred expenses, the amount you add to the estimated cost will represent nearly net profit; assuming, of course, that your estimate has been carefully made and that you can make it work out substantially as you have figured.
If you have to maintain offices, superintendent, bookkeeper, stenographer, telephone, team, etc., you have a certain fixed expense per year which you can readily total up. Now this can be figured to a percentage of the total business you can, or do, handle per year. Having ascertained this percentage you must take it into account in putting profit on the job. For instance, if you want to make a net profit of 10 per cent, on the job upon which you are bidding and you find that the office expense averages about 3 per cent., your gross profit should be 13 per cent.; so we add 13 per cent, to the total estimated cost, making the bid for the work $34,673. Our own experience has been that the fixed expenses of doing business, on a basis of our doing about $250,000 per year, are about 3 per cent. This includes a fixed salary for each partner per year and all expenses connected with running the office, shop and yard, etc. In talking with other contractors I find that they have fixed expenses from the above to as high as 7 or 8 per cent. Success in doing business in the contracting lines in a great measure depends upon
Area and Contents of Building
Now that our building is all figured up it is an excellent plan to make note of the area and cubical contents of the building and to figure out, from the estimated cost, the cost per square and per cubic foot.
In order to have the information thus obtained of any value to you, the method of measuring every job must be as nearly uniform as possible. There cannot be much chance for a lack of uniformity in obtaining areas, but there are great chances in computing cubical contents. I will give you my methods for computing these quantities and trust that they may be of value to you.
Compute the area of the first floor from outside to outside of walls ; if the building is irregular in shape divide by imaginary lines into squares, rectangles, triangles, etc., and compute each division and add for total area. In the case of a dwelling or similar structure with piazzas, measure same and add to area of main building one-half of their area. If the second -story overhangs the whole or any part of piazzas, treat that particular part same as main house, adding full area to first floor area. Porches, piazzas without roofs, unless quite extensive, bulkheads, etc., take no notice of.
Enter the area obtained on the estimate sheet. Now divide the amount of estimate, as completed, by the number of square feet, thus obtaining the price per square foot which the building in hand figures. In this case it is practically $7.20.
To obtain the cubic contents multiply the1 area obtained for the first floor, exclusive of the piazzas, by the height of the building, taken from the bottom of the footings to the average height of the roof. Multiply the area of the piazzas by their height taken from the bottom of the piers, or other foundation, to the average height of their roofs; in case of a flat roof surmounted by a balustrade, take height to the top of balustrade. In case of an uncovered piazza or platform take height from bottom of piers
total, entering said total contents on estimate sheet.
Having done this compute from the estimated cost the cost per cubic foot. With the contents assumed for the building we are dealing with, the cost is practically 20 cents per cubic foot, as shown in Fig. 35.
If you will take the trouble to always work out the square and cubic foot costs on every building you figure or build you will find that the information thus obtained will be of great value to you, especially in approximating the cost of prospective buildings for owners or architects.
If you have several hundred estimates to look back to you can always find several that compare favorably with the building you want to approximate, thus having a price at hand to use for such figuring. You can also check your detailed estimate to some extent by the cubic foot price. For instance, if you were to figure a similar building to" the one we have just been through together a month from now, when there has been no material change in price of stock and labor, and upon working out a cubic foot price it came out, say, 13J cents, you should go over your figures again to see if there has not been an error made in some computation; or addition of a column of costs; or some important item omitted. Failing to find any errors, analyze the two' estimates side by side and account for any such difference in costs. If there is any such difference in cost there are reasons for it and they can usually be found, if carefully looked for. You will be surprised to find how near the costs per cubic foot will run on similar buildings.
Examples of Making Approximate Costs
As an example of short methods for determining approximate costs, I will give in detail my answer to a correspondent who wanted information in regard to a building 40 x 70 ft. and about 20 ft. high, structure to be of cheap construction, roof flat, finish plain, etc., same to be built for some summer amusement enterprise.
At first glance I should say in reply to his request that such a building was worth about $.02J per cubic foot. The cubic feet may be computed by multiplying the size of the building as given, 40 x 70 ft., by the height of structure from grade to the average height of the roof. Assuming the structure to be built upon posts 7 or 8 ft. apart, the bottom of sill to be about 1 ft. from grade, the roof to have a pitch of J in. to 1 ft., the ridge running parallel with the length of the building and the building being 20 ft. high from bottom of sills to extreme height of roof, there is a total height— grade to average height of roof —of practically 20 ft. Thus 40 x 70 x 20 ft. gives the number of cubic feet in building, making 56,000 cu. ft., which at $.02^ per foot makes $1400. In this manner an approximate cost is arrived at quickly, but you must be in possession of cubic foot costs that have 'been worked out in other structures in order to determine about what price to use.
Now to analyze this building for approximate cost a little more thoroughly and thus see how near the mark we come when assuming a cost of $.02^ per foot let me demonstrate another short cut in estimating.
I will assume a foundation of posts about 8 ft. apart, set about 3 ft. 6 in. in the ground around the entire outline of the building; also two rows of posts, same spacing, the length of the building, for girders under floor joists. This would make 60 posts, which, set in place and cut off to receive sills and girders, would be worth at least $1 each, making $60.
much less than 2 x 8 in. placed 20 in, on centers, and if of this size and spacing each square foot of floor area would require £ i't. B. M. of frame. In order to cover sills, girders and waste, I call it 1J ft. B. M. per square foot of floor. Now work out a cost per square foot for first floor complete, thus:
Now I take the outside walls. The perimeter of the building is 220 ft. This multiplied by the height, which averages about 19 ft. 6 in., gives us the area of the walls, same being about 4290 sq. ft. I will assume 2x4 studding 20 in. on centers covered with some form of siding, and work out a price per square foot as follows :
I now take up the cost of the roof, assuming that there is a 40-ft. span, which will require either trusses or columns and girders to support same. I will call the rafters 2x6 in., 18 in. on centers, which equals f ft. B. M. of frame per square foot of roof. Without going into a lot of figuring to determine accurately how much lumber would be required for trusses, I assume a quantity equal to that already figured out for rafters, thus making each square foot of roof take 1^ ft. B. M. net of frame. Add something to this for waste and call it 1^ ft. B. M., and work out a cost per square foot of roof.
I next consider the doors and windows. Six windows complete I figure as worth about $5 apiece, not stopping to go into an analysis of the cost, knowing without doing so that anything in the shape of a double hung window of average size is worth at least that amount. This makes $30 for windows. There are to be three doors, and these I figure at $8 each, complete, making $24. Now I allow something, say $40, for such outside finish as would be required, and the whole ground, except painting, is covered with sufficient accuracy for an approximate cost.
Assuming that walls would have two coats of paint outside and that there would be some little painting inside about doors and windows, I refer to my wall area (4290 sq. ft.) and immediately call this 500 sq. yd., which at $.12 per yard for two coats of cheap paint makes the cost of painting $60. Thus I have as costs:
To this total must be added something to cover overhead expenses and for profit, and I should consider 10 per cent, little enough, so I add $121.80 to the approximate net cost of $1218.05, making $1339.85. Having arrived at this last amount as representing the cost of the structure plus a fair profit, I would be prepared to tell a prospective owner or architect that a building of this character and size could be built from $1200 to $1400, the exact price depending upon circumstances of site, size and spacing of timber, quality of materials used, etc., and the amount of profit a contractor happened to want at the time of figuring.
Since writing the above I have looked back in my estimates for something similar in the way of a building and found my estimate made in April, 1907, for a structure of the same char-
acter, which we built in Wonderland Park, Revere, Mass. This building was 30 x 98 ft., and practically 23 ft. high, and on the basis of our bid figured out $.02} per cubic ft. The building was erected upon 12 to 14 ft. spruce piles, driven into the marsh by a hand machine, and the facade was quite ornamental. Otherwise, the similarity between the two buildings is very marked, if I draw correct inferences from the correspondent's description of his proposed structure. Our price as above gave us a reasonable profit.
I have taken some time and used a good many words in describing this method of making an approximate figure, but I made the actual computation in about 6 minutes before starting to explain them, and if the correspondent is half a mathematician he can do likewise.
Razing, Shoring and Temporary Protection
In the preceding chapters on the subject of estimating I assumed a new building for the purpose of illustration. I think I made it plain, although I do not recall having expressed it in so many words, that I do not consider the estimating of costs of buildings an exact science. While results are reached, as a rule, by various mathematical processes, the element of judgment enters so largely into each and every item, especially in methods of measuring plans for quantities, allowances for Avaste and determining cost of labor, that on the whole such estimating may be considered more as an art than a science.
I doubt if it will be questioned that determining the probable cost of alterations and remodeling operations requires the exercise of even greater judgment than new work. Nearly all that I wrote on the main subject in the preceding chapters can be applied in a measure to the work now in hand, and in the matter to follow I will try and bring out details of the subject especially applicable to alteration work.
In the first place, have a method or system and stick as close to it as circumstances will permit. My former chapters suggested taking up the items in the order in which they appear in the specifications, not forgetting meanwhile some matters seldom or never mentioned there. In case there are no specifications take up the items in the logical order in which the work would be done.
Before beginning to figure at all you should visit the building which it is proposed to alter and carefully note existing conditions. This is an absolute necessity, as, at best, it is difficult to make plans for an alteration show with accuracy just what is to
the cost of accomplishing it.
It is very important to know whether you are going to have a vacated building or must. do the work in such a manner that the business of all occupants can be carried on. If the latter is the case you must find out about how much room you will have given you at a time in which to work, and what measures for the protection of occupants' stocks must be taken.
These two questions settled, you can see what advantages or disadvantages you will have to work under. It is highly probable that some work will have to be done overtime. At "double time" and by artificial light, construction work of all kinds is most expensive— so expensive, in fact, as to be prohibitive at times.
The loose-leaf book sheets described and used in my former chapters are perfectly adaptable for the present case, and as the carrying of quantities to the same was sufficiently described there, I will not use them in this case, but stick wholly to text.
This is the first and usually a very important item. Generally there is a little of everything to pull down and get into shape to be used over again or be carted away. By taking each part separately; such as stone work, brick work, plastering, frame, etc., and analyzing it to determine the probable amount of labor involved, and adding for a total, a much closer and more accurate estimate will be made than if you try to consider them collectively.
Bear in mind while making this analysis, that such of the razed materials as are to be removed must be brought out to some place accessible to the teams. In some cases this involves considerable handling under adverse circumstances. In any case the probable cost is a matter of judgment rather than mathematics. Where materials are to be used over again it is unwise to make any allowance for them unless there are large quantities in excellent shape. There are any number of little items and wholly unforeseen circumstances that develop in an alteration job, and the salvage on materials is needed to offset them.
As the work of razing progresses many existing parts that are to be retained must be shored. As most of the material used in shoring is heavy timber or old steel beams kept in stock for the purpose, the cost of this part of the work is practically all labor and teaming. By making a mental survey of about the quantity of material required one may judge of the teaming to and from the job. Now by taking each separate wall, floor or other part to be shored, and mentally analyzing, we are able to determine the probable labor required to place shores and remove them when other, or permanent, support has been installed. Labor of cutting needle holes in brick or stone, or slots in masonry walls, holes through floors of frame or other construction, must be foreseen and taken into account.
It may be possible to do all shoring on a large job without a great quantity of timber and iron if the work is arranged in such a way as to permit of certain parts being shored and secured and then the material may be used over several times. This saves considerable in teaming, but it must be a matter of judgment with you whether to resort to this saving or not, as it may involve other expenditures that would soon more than offset any saving made. In the large cities where numbers of difficult and extensive jobs of shoring are done every year there are contractors who make a specialty of this work, and there will be cases when it will be advisable for you to take sub-bids and sublet such work to one of these men.
Temporary Partitions
These are usually made of matched stock J in. thick. In cases where extreme precautions must be taken against dust it is customary to paste paper on the exposed side. I have found that the cheapest way to paper partitions if there is much area, is to have a paper hanger do the work, using wall paper that can be found in any wall paper store, that is out of style, and can be purchased for 2 or 3 cents per roll. This should be put on with the face of paper toward boards, thus leaving the plain color of back in sight, and two thicknesses should be applied, otherwise the boards will season enough in a few days to break
the paper at each joint. By assuming imaginary lines on your plan in the various places where you have concluded that these partitions will have to be erected, it is a simple matter to obtain areas and quantity of stock required.
Masonry, Iron and Steel, Roof and Metal Work
Most excavation in alteration work has to be done under very adverse conditions, and the labor involved to get excavated material to the street or to the teams must be taken into account. As the conditions are seldom twice alike the cost is all a matter of judgment. You must frequently excavate considerably more than strictly implied by the plans, in order to make room in which to handle materials or to give the men a chance to work. After listing on the estimate sheet the dimensions of the several excavations you must mentally average the conditions and determine upon a price per cubic yard, or other unit, including the disposition of the material, on the premises or elsewhere. Under conditions frequently occurring in our city (Boston) the cost, including teaming away, will be as high as $2 per cubic yard.
Concrete Foundation Work
It is generally easy to locate on the plan the new foundations, and there should be sections showing thicknesses and other particulars. If no sections are shown you must use your judgment and take the chances. I am sorry to say that the larger part of our architects give very meager sections, either from their inability to foresee conditions or unwillingness to spend the time and money necessary to have test pits dug side of existing foundations, so that it may be known to a certainty what conditions exist. There is no difference in the method of taking off quantities or entering dimensions on the estimate sheet than would be the case in a new building. There may be, however, and there usually is, a great difference in the cost, and practically all of it comes in the labor. Frequently the concrete must be mixed in an alley or a distant part of the cellar, then carried in pails or mortar hods to the location of the work and be deposited in shovelsful. These conditions, coupled with the fact that there is seldom much in bulk in a place, and many places, make the cost run from $8 to $15 per cubic yard for the ordinary mixtures. Pick out what seems to be an average piece of foundation and
picture yourself there with the help and putting it in. Arriving at what you consider a fair estimate of the labor, figure out what it would be per cubic yard for the number of yards in the piece of your foundation used for the experiment, and you have a fairly accurate cost per yard for labor, to which you can add costs of materials, which latter would be as usual in any work, old or new, thus obtaining a price per yard to use for the whole quantity.
All my explanations above for concrete apply fully to foundations of other materials. The price might be different on account of local conditions, but the method of arriving at a cost would be the same as for concrete.
Areas of new concrete floors would differ in no way but price (and this all on the labor) from new work. In making good existing floors, where they have been broken out to get in new foundations, pipe trenches, etc., do not measure or assume too small an area. Nine times out of ten, unless you are there yourself, about twice as much as was necessary will be broken out. This statement about cutting out to admit of the installation of new parts holds good on more than this one item. In fact, it must be borne constantly in mind when figuring an alteration of any kind. In making price of concrete floors picture to yourself the disadvantages under which the particular job in hand will have to be done and be governed accordingly.
The brick work found in the usual alteration job would not be altogether unlike that in a new building. The only difference that amounts to anything is that instead of the continuous and connected walls, there are detached walls, parts of walls, openings made or filled up, etc. The work being thus disconnected and scattered, will cost a great deal more for labor than would be the case under normal conditions. In making a survey of the number of brick required it is seldom advisable to take into account any old brick taken out, as the cleaning and care of these latter until such time as they can be used, usually costs as much as new brick delivered when and where wanted. Quanti-
ties should be entered on your estimate sheet the same as demonstrated for new brick work (see estimate sheets in preceding chapters). In taking off quantities I always disregard all openings cut in existing brick work for doors, windows, etc., and immediately after making brick survey, count and enter on estimate sheet the number of these openings, noting the average size of same and thickness of walls in which they occur.
In making a price per 1000, laid, proceed the same as for new brick work, taking care to fully consider the question of labor before assuming the probable cost. In my judgment a first-class mason will only be able to lay one-half as many brick per day as on new work, on account of the usual peculiar disadvantages attending alteration work. Now consider the openings to be cut in walls : The cost in this case is probably from 90 to 95 per cent, labor, so that in most cases you can consider it purely a labor item. Picture yourself cutting the average opening and toothing and bricking up the new jambs. Having determined to your own satisfaction how long it would take, figure the cost of labor involved, not forgetting before carrying said cost to the estimate sheet, that you are not going to cut these holes yourself, but that some man in your employ about half as interested to see it done as you are, will do the work, and adjust the supposed cost accordingly.
The item of washing and pointing will invariably cost more than on new work of equal area. This work, in either case being almost wholly a matter of judgment as well as labor, must be analyzed as such and in the same manner as in Chapter IX.
Cut Stone
The only difference in cost of cut stone of any kind, or ornamental terra cotta, would be the additional labor involved in setting it under adverse conditions, and with little or no rigging in many cases. Being wholly a matter of judgment, you can see the great benefit of having some reliable data at hand from which to draw conclusions. Otherwise the estimate for cost is a guess, pure and simple.
other than that you must fully consider the labor cost per unit of each of the above items, and make it sufficient to cover the cost on the particular job in hand, considering all of the surrounding conditions tending to make whole more expensive.
Iron and Steel
The process of taking quantities from plans would be no different than in the case of new work, except that, as generally drawn, plans for alterations are apt to be somewhat vague, and the architect, to protect himself and the owner, embodies clauses in the specifications that compel the builder to "supply all needed materials whether shown or specified" to accomplish the desired result. While this is decidedly wrong, there seems to be no immediate help for contractors, on account of the general lack of organization among them. This makes it necessary for the builder, when estimating, to foresee the possible wants of the job beyond that shown and listed, and figure upon them. Having found and listed all of the iron and steel shown and "implied," compute into pounds and set a price. The cost of setting will usually be as much as double that of new work for reasons before stated, and not infrequently the handling and setting will cost as much as the material itself.
We recently had occasion to set eight 2-ton girders and six 1-ton columns all built up of structural shapes and costing $70 per ton delivered, where the cost of erection exceeded the cost of material, being about $75 per ton. These girders went into the ceiling and the columns extended through the first floor to the foundations in the cellar, in a large and busy jewelry store, where business was never suspended for a moment during the operation. All handling was done with hand rigging, and everything was taken into the second-story windows and lowered into place, preparations having been made for this by building tunnels on the store ceiling— which fortunately was quite high— for the girders and boxes about 4 ft. square through the store in which to lower and set the columns. While circumstances are seldom as adverse as this, they are usually of such a nature as to require the exercise of fine judgment to arrive at a safe probable cost for labor.
Roofing and metal work, and marble and mosaic work, are subject to the same changes in price as most other items entering into alterations, but, as a rule, the increase is not so marked. There would be no material change in method of listing quantities, but care must be used where old and new work join, to figure enough material. There will be cases where it will be cheaper to tear away and dispose of existing work and supply new than to retain same, even though the plans and specifications permit of said retention. A little analysis of questionable parts should determine for you the better course to pursue in estimating.
Carpenter Work, Plastering, Painting, Plumbing, Etc.
In alteration work that, is not too extensive I should make one item of frame, boards and furring, entering on estimate sheet the quantities of each item, care being taken to extend your measurements sufficiently to care for all razing of existing parts thought probable or possible. Compute into feet, B. M., and add for a total and determine upon a price for labor of installation. Having settled this latter, compute total price per ' ' unit ' ' ( 1000 ft., B. M.) labor and stock and carry out this price.
Materials resulting from the razing of parts of the work and stock bought and used for staging, temporary partitions, may frequently be used, but old and second-hand materials always involve more labor, and to hold same on premises and care for them until such times as they can be used costs money. In nine cases out of ten it is wiser to make no allowance for such materials. My advice would be to consider carefully before allowing anything for salvage on old materials of any kind resulting from the work of alteration.
The method of obtaining quantities, also the classification for all work coming under the above head, would be practically the same as for new work. The principal point to keep constantly in mind is to make ample allowance in measurements where old and new parts join. It must also be borne in mind that it usually costs more, both in labor and stock, per unit to match old work than to carry it out entirely new.
If an alteration is at all extensive there will be very little plastering left, except in parts of the building that are practically unchanged. There is hardly an item in the building
where the increase in cost per unit is as great on diminishing quantities. For instance, in an ordinary case of new work of reasonable extent, we would figure 40 cents per yard for twocoat work on wood laths. If we were going to put a new ceiling on a room of ordinary size in an unoccupied house, say, 25 sq. yd. area, the actual cost would surely be in the vicinity of $25, or $1 per square yard. If we were to go into an occupied house or place of business to put on a patch of a couple of square yards the cost would probably be about $5, or $2.50 per square yard. If there was but a single square yard under the last stated circumstances the cost would not be affected enough to take notice of. In the light of these facts, you can see that in alterations, where the work is in detached areas, frequently joining existing work, that the plastering operation almost becomes patching. Many times it will be cheaper not to try to save much plastering. In surveying for plastering, if a ceiling or side wall had about' half its area of old plastering left, thus leaving about one-half new, I would either measure as though the entire space was new and use 40 cents per yard as the cost (two coats on wood laths), or take as near as possible the actual area to cover and double the price. Such a rule as above would apply to an average case of alteration work, but as each case presents differing circumstances it must not be applied inflexibly, but varied as the dictates of your judgment suggest. The question of drying plaster on work of this character is seldom much of an item, as there is usually an existing heating plant in operation, and the principal items of cost against drying would be setting radiators temporarily. The item must not be lost sight of, however, as in all cases it costs something and under some conditions would closely approximate new work.
In surveying quantities for painting in remodeling work, provision must always be made to cover the entire walls or wood work of a room with the last coat if a good job is desired. It is practically impossible to paint a part of a room and have it match or look like the part that was left undone, no matter how good the undone part may be. Thus the principal point to remember in measuring painting on an alteration job, is to con-
PLUMBING, HEATING, ELECTRIC WORK 143
sider the last coat as covering practically everything usually painted. The price per coat on the several coats preceding the final one will also be more than would be the case in new work; but how much will be wholly a matter of judgment. The increase in cost in average cases would be about 30 per cent.
Plumbing, heating and electric work, etc., would be either figured by men of the respective trades or must be "sized up" as outlined in Chapter XX. This "sizing up" must be on a liberal basis, as considerable of the existing work will be damaged or absolutely destroyed in the performance of the other parts of the work. The above, coupled with the fact that the work usually has to be done in cramped quarters and possibly overtime, makes necessary the careful consideration of the matter before forming an opinion as to the probable cost.
Now, having treated practically all of the items entering into an ordinary alteration job that differ enough from new work to make necessary special treatment, we come to the items of "expense," such as watchmen, telephone, lockers and sheds, insurance and bond, carting debris, etc. All of these should be considered separately, and the estimated cost entered on the estimate sheet.
Having thus determined the probable cost, looking at matters from the safe side, which, by the way, is the only way on remodeling if you wish to make money, add what you think you should have for profit, not forgetting in doing this the fixed office expenses connected with your particular business.
From my own point of view, an alteration, if of any extent or in any way complicated, will require double the personal supervision, involve one in more chances for accidents to workmen and the public, and develop more expenditures for unforeseen conditions than a new operation of twice the size, considered in dollars and cents. I would, therefore, recommend that the margin of profit be figured as large as from 10 to 20 per cent. If you cannot get the work on about this basis letyour competitor have it, and put your feet up on the desk and smoke.
An Interesting Example of Alteration Work
I have purposely left until the last the consideration of a phase of figuring the above described class of work, and now will try to show you how to arrive at the probable cost of some operations that can hardly be figured on a "stock unit" basis. I do not know of a better way to explain than to cite an instance that came to me several days ago. A man owning a fivestory building in a part of Boston where land is worth about $60 per square foot and rents are in proportion, has a first floor occupied as a store, about 18 ft. 6 in. high, and a second story occupied as offices, 12 ft. high. The extreme height of the first story was brought about by lowering the first floor about 6 ft. in the course of remodeling the structure, from a dwelling to a store and office building, some 10 years ago. Now a store of 10 ft. to 11 ft. in height and offices of 9 ft. to 9 ft. 6 in. will bring about as much rent and sometimes more than the higher ones, and he is considering the possibility of working another floor into the space between the street, or first, and the third floors, thus gaining space to divide into offices that would bring in about $4000 more rent per year. The question he asked me was, "What will it cost to put another floor into the building, moving the present second floor up or down, so as to leave an 11-ft. high store, and cut up the new story gained into offices, practically like the present second story?" Now, right here was a matter that could not be figured on a "stock unit" basis or guessed at with any degree of accuracy, namely, the raising or lowering of the present second story. By telling you how I arrived at what I thought would be about the cost you can see how to handle such out of the ordinary operations.
Lowering the Floor
The first question to decide was, whether to raise or lower the existing second floor, and after a half hour's examination of the premises I concluded that it would be more economical to lower
the floor than to raise it, as there were no partitions in the store, and the existing second floor had considerable steel and heavy frame in it to take care of the 24-ft. span between party walls and support the partition loads coming over it the rest of the way up in the building. The new floor to be put in could be much lighter on account of the spans being cut in half by the partitions. I then proceeded to analyze as follows : Razing all finish, doors, plumbing and heating, etc., in second story and storing for the time being on the first floor; I pictured myself there with two carpenters and four laborers, and concluded that in one week I could accomplish the above work. This would represent an expenditure of $129.60, made up as follows:
The next thing was to shore the present third floor, doing it in such a way as to support the second story bearing partitions and not have shores interfere with the lowering of the second floor. This, I assumed, could be accomplished by putting a 6 x 6 in. strut in the main partitions about every 8 or 10 ft., same running from street floor to the partition cap under third floor joists. As these could not be inserted in one length, I assumed that the most logical way to install shores was to use pieces about 20 ft. long, which could be shoved through a hole cut in the second floor between two joists, the top being placed under the partition cap (the lath and plaster between two studs on one side of partition having been removed to make room for it), and the bottom to rest upon a piece of oak plank with two jack screws under it, and the distance from here to the first floor to be taken up by cribbing. When these shores are all in place I would then turn the jacks all up together, until the weight on the studs nearest the shores had been relieved. There would then remain to be relieved of weight the four or five studs between shores in the middle of the space. I am assuming, as is usual in our construction, that the partition cap is either 2 or 3 in. thick, and, this being the case, you can readily see that, while the shores would relieve the weight
Laying Out Main Partition
I should now lay on the existing main or supporting partition the exact location of the new floor, which is to be inserted when the present second floor is lowered. The top of the joists of this new floor would be about 9 ft. 5 in. from the ceiling. Now I would relieve the weight on the partition from shore to shore •(the large ones already in place) by a little temporary shoring of the third floor by a plank on the ceiling and several studs driven in under it, and cut off the studs 3 in. higher than the top of the joists of the proposed new floor. Now I would slip a piece of hard pine 3 in. thick by the width of the studding under the ends of the studs (previously removing the bottom of partition, which was cut loose), letting this piece run tight to each shore. Next I would nail the bottom of all studs to the shoe piece, putting a chunk of studding under where it intersects the main shores, spiking it securely, and then run braces of studding from the shores to the center of the shoe piece in a manner similar to that in which you would truss the space over a large door opening in a partition.
When all of this work is done the weight in the center of the building from the third floor up is all transferred to the first floor, which, if not strong enough in itself, can be shored from the cellar bottom, and we are free to lower the present second floor the required 6 or 7 ft. Now figure up the stock and labor that would probably be necessary to have accomplished the above result. The building is 90 ft. deep. I assume 10 large shores, 6 x 6 in. x 20 ft., = 600 ft. B. M., at
existing second floor about 7 ft. 6 in.
I found upon examination that the second floor had steel girders composed of two beams about every 9 ft., and that the joists between them ran in the same direction. It was fair to assume that the girders entered the party walls 8 in., and the joists 4 in. After consideration, I made up my mind that the easiest way to cut this floor loose for lowering was to slot the walls under the girders down to the new level and to cut the joists off about 6 in. from the wall and to put in a 5-in. trimmer from girder to girder, using hangers to carry the trimmer from the girders and also hanging each joist to the trimmer. Before doing this, however, the floor must be prepared for lowering by running a 3 or 4 in. plank along the ceiling about 3 ft. from the wall and parallel to the party walls, and erecting cribbing at intervals of 8 or 9 ft. from the first floor to within the length of an extended jack screw of the plank stringer. Then place the extended jacks and take the weight with them.
Now having in my mind ?s eye this floor down to the new level, there remains to be done, when the new third floor has been put in and the new second floor studded out, the removal and teaming to the locker of the jacks, crib stock, shores, etc., and this I assumed could be clone for about $75. Thus I had costs as follows :
The new floor and partitions, the repairs to the floor that is Jowered and the necessary changes in openings of front and rear walls are readily figured in the usual way on a "stock unit" bash and the cost thus worked out, added to the $827.25, is the supposed cost of the whole operation, to which should be added profit. On a job of this character 25 per cent, would be little enough, as there are many hazards, and from its being so different from the ordinary operations there is a liability to underestimate in spots.
Thus by dividing a large operation into a number of smaller ones and considering each division separately, a pretty accurate analysis of the cost can be made, when considering the operation as a Avhole, one would be wholly at sea. In actual practice a number of these minor operations would be carried on simultaneously, thus entailing less time than would appear from the analysis of parts.
I have assumed that the person figuring work of this character" is capable of taking a crew of men and superintending the operations, for if he cannot do this it is improbable that he will ever be able to estimate with any accuracy upon such work. I think I may safely say, however, that it is possible for a man to become fairly expert in estimating new work, even if he could not take help and perform it, if he thoroughly understands plans and has access to tabulations of costs that have been worked out by others. Such men should never let opportunities go by to get right onto the work and see it performed, making notes of the time required, methods pursued and order adopted, in the various parts of the work, as information so gained is of vastly more help in analyzing the questions that come up than copious writings such as this.
Steps Necessary to Start Building Operations
A builder who has the reputation of doing good work, finishing it promptly at or before the agreed time, and paying his bills, does not want for plenty of work at good prices. I am going to try and explain to the readers, as I see it, how to secure a reputation for doing good work, how to get the contracts completed on or before time, and in doing both of these things make sure of plenty of work at prices that return something more than a mere living.
To do good work it is necessary to buy first-class materials and take proper care of them after they come into your possession ; hire first-class workmen and see that they are properly directed and supervised. Buying first-class materials does not always imply paying the top market price. A builder with a reasonable amount of capital and Avhose credit is known to be good, usually gets the best materials for less than the indifferent builder of doubtful credit pays for inferior goods.
Care should also be exercised in the placing of sub-contracts, letting work only to such men as are of good character and who have established a reputation in their particular line.
All material purchased for a building should be delivered at such times as will insure some one in authority being present to receive it, and should then be unloaded with such care as the nature of the material requires. If protection from the elements is necessary see that canvas, lumber, sheds, etc., as needed, are at hand. Three-fourths of the jobs I see in process of construction look as if there had been a cyclone in the vicinity the day before. All sorts of stock is strewn through the building and round the
premises ; window frames are mixed up with brick ; outside finish on the floors is being walked over ; mortar bed is so placed as to spatter the face brickwork and the debris of several months' operations is still under foot, scattered about the premises. I do not need to tell the reader that the best of stock delivered on one of these jobs soon becomes second or third grade stock, causing annoyance to the owner and architect, and often causing the rejection of material, even after some of it is in place. Replacing stock thus damaged is a constant drain on the possible profit of the job. The improper handling and storing of stock in this way can have but one result upon the labor, and that is to make it cost more than it should.
The cause of most of these evils is the contractor himself. If the foreman finds that the contractor will not stand having stock so handled, he will very soon do differently. If he will not follow suggestions or orders from headquarters, in regard to these matters, it is time to get a new foreman.
When Starting a Job
When about to start a new job of any size go to the site with the foreman who is to be put in charge of the work, taking the plans along, and spend anywhere from an hour to a day right on the spot studying the conditions. Determine the location of the derrick and engine if the work requires them; locate the office locker, tool and stock shanties; pick out a place to make mortar ; a place or places to pile brick ; places to pile up lumber and a place to frame it; map out a good road to or around the building, locating it in such a way that all materials are readily handled from the teams to the appointed places, or so that heavy materials may be pulled under the reach of the derrick boom and be taken from the teams and piled outside or landed on the building without any unnecessary or double handling.
In locating all piles of materials and shanties try to foresee the various trenches that will have to be opened or yard work that will have to be done and figure out the probable time that such excavations or work will have to be started, taking care not to pile materials in these places that will not be used up before the time for doing the work arrives. For instance, there may be some retaining walls, catch basins and drains which, upon due
reflection, you may conclude better be left until the superstructure is up. This being the case, you may safely pile such brick and lumber on this part of the lot as will be used in the superstructure, knowing that they will all be incorporated in the building by the time you are ready to take up the retaining wall and drain work. On the other hand, it might seem advisable to open these trenches for drains and walls and put them in at once thus getting something done while you are assembling the more complicated materials for the principal work. You would then pile stock elsewhere or delay delivery for a few days until such time as the drains were in and filled over, after which you could use the location for piling stock.
Having thus mapped out the matters above referred to, the next step is to put the work in operation. Build the office and install the foreman with a complete set of plans and specifications. Next build the tool shanty and begin installing the equipment of hand tools, such as picks, shovels, bars, barrows, scythes, axes, timber dollies, rollers, peavies, ropes and blocks, winches, lanterns, etc. Everything that there is a possible chance of wanting should be included, so that, should there arise the want of anything, it is immediately at hand. This avoids delay and delay is expense. Enough work can frequently be accomplished with the proper tools to pay for them several times over on a single job.
Now give the foreman as many men as he can use to advantage and begin to pile up stock. Don't be afraid to pile up stock. Lots of time is lost on the majority of jobs by negligence in ordering materials and piling them up in advance of their being wanted. A job that requires 500,000 brick should have at least 100,000 piled up on the premises while the foundation is going in and before a brick is laid. When brickwork is started plans should be made to have about as many brick delivered per day, or per week if they are coming by cars, as will be laid in the corresponding time.
The foreman can accomplish but little on the job if the "office" neglects its share of the work. We have left him on the work with a complete set of plans and specifications, an office locker, tool locker and plenty of tools, and we will assume that some "stock" materials are already arriving and being piled up for immediate and future use.
Among the ' t stock ' ' materials above referred to would be such as follow: cement, crushed stone, common brick, sand, lime, boards, furring, studding, etc. A reference to the estimate sheets tells the quantities of all such materials, and a little work at the telephone will soon demonstrate who has the particular kinds you want. Get the prices, determine from whom you will buy and give orders for delivering certain quantities in a given space of time.
We neglected to state that we consider it necessary to install a telephone in the foreman 's office at the building as soon as possible. We then instruct the foreman as to what has been ordered, as well as from whom, and as to what deliveries have been agreed upon, instructing him to see that the deliveries are kept up as agreed, using the telephone to that end, and notifying the office if his telephoning does not bring results.
But to get back to the office end. Here the work should be divided in such a way that some one man is responsible for each particular job. If there are two or more partners there should be an immediate agreement as to who is. to run the job in hand. We do not mean by this that the remaining partners should have nothing to say about the job. They should be advised of all matters of consequence which arise and a free discussion of the best course to pursue, under the circumstances, agreed upon. We all know that two or three heads are better than one. We simply mean that all matters pertaining to the job, whether they are with the architect, owner, city departments, material men, subcontractors or foreman, should be brought before the partner in charge of the job, and all orders, decisions, correspondence, etc., be attended to by said partner. Several men cannot run one job successful^. There will be confusion in ordering material, conflicting orders given to the foreman and sub-contractors, conflicting statements made to the architect or owners, the net result of which will be confusion on the work and loss of confidence of
the above conditions exist.
Should the builder, or firm of builders, have a superintendent in their employ and he be chosen to run any particular job, all orders and correspondence pertaining to the job should be attended to by him. Otherwise the foreman and other employees on the job and the sub-contractors will not pay the attention to his orders that they should. It is not a necessity that the superintendent transact all the business of the job with the architect or owners, although no harm would be done if he is sufficiently diplomatic and entirely in your confidence. It is fair to assume, however, that a superintendent would refer more matters pertaining to the job to his employer or employers for a decision than a partner would. Especially would this be the case until such time as a superintendent had demonstrated to his employer his ability and fitness to handle all matters relating to the job.
The Man in Charge of the Job
It now having been agreed upon, in the office, who is to handle the job we have in hand, the party chosen must begin his part of the work at once. A full set of plans and specifications should be on file in the office at all times, and if the building is of any size or at all out of the ordinary, a second set of plans is a great convenience, if not an absolute necessity. By having this extra office set you can lend the drawings to material men and sub-contractors with whom you are doing business and not leave the office without plans of the operation. We have seldom seen the time when, the office set of plans being loaned, something did not come up before they were returned which called for a reference to them. If the architect or owners will furnish only one set of plans and specifications we should buy the two extra sets. We have, however, never met a refusal from a reputable architect to furnish three or four sets of plans. As they usually have five or six sets printed to send out for bids, it is not an additional expense to them to supply the contractor's reasonable wants in this respect.
We find the most convenient way to keep plans in the office is flat in a draw. Have a case of large, shallow drawers in the office and take a drawer for each job, labeling it and taking pains to
put each plan back in the right drawer when through with it. It is a serious inconvenience to have to unroll plans and weight them down when using them, and the method described overcomes this objection, and is now in use nearly everywhere by architects, engineers and contractors. Another thing is to cut each sheet down to the smallest size possible, without cutting into the actual working drawing. This saves handling lots of superfluous paper every time you refer to the plans.
We left the foreman supplied with tools, help and some materials. It is now necessary to let the sub-contracts, especially those for such parts of the work as will be soon wanted. Among these would be cut stone and steel and iron work. In all cases more or less work must be done on these materials before they can be delivered for installation in the building. The ! or ^ in. scale drawings, with such larger scale plans and sections as are usually a part of the contract drawings, are sufficient for taking off quantities, and the contracts should be made at once to permit the sub-contractor to purchase such stock as may be required if he does not have it already on hand.
A contract should be drawn up with each sub-contractor binding him to furnish certain materials at certain specified times (erected in the building if his contract covers erection), with a penalty of so much a day for failure to comply with the times of delivery or installation set forth in said contract. You will seldom have to pay any bonus if you take a little care in setting the dates, giving them just about as little time as it is possible in which to get out the material, and, if a part of their contract, to install it. What bonus you may have to pay will be money well spent.
While the sub-contractors are figuring and before the job is a week old, you should carefully study the plan yourself and considering the total time allowed you, for the completion of the whole work, make a written schedule of the condition the job should be in each Saturday from start to completion, setting forth clearly what part of your own and each sub-contractor's work should be done. Set your dates for sub-contractors and deliveries of materials from this schedule. Keep the schedule in your desk and compare the condition of the job with it frequently and make it a point to keep the work ahead of the schedule.
and are ahead.
Having thus laid out what must be accomplished in order to complete the work on time and knowing the quantities of material required, you can readily figure out about how many laborers, masons and carpenters should be employed to accomplish the required result. Don't forget to take into account bad weather. Provide the foreman with ample help and see that he is kept supplied with sufficient stock to work every man to advantage.
With the ordinary stock materials piling up on the site and the principal sub-contracts let, you must now find time for scheduling dimension frame, window frames, etc., and getting your orders placed in time to have deliveries made that will permit of your keeping, or beating, your scheduled time.
Other matters must also have your attention. You and your sub-contractors must have details and you must foresee those wanted first and take steps with the architect to get them. Don't request him to make them for you "as you will need them soon." Tell him that you must have them at once or the work will be seriously delayed. It is well to impart this information to the architect by letter, following the first letter with others if necessary, until such times as you get your details. If it gets to a point where you are actually delayed by his failure to furnish certain details, set it forth clearly in a letter to him and claim an extension of time from date of letter until the drawings required are forthcoming.
By keeping copies of all your letters and preserving all of his, in a file or files provided for the particular job in hand, information that may save you from trouble or lawsuits before the work is completed, accepted and paid for, is in your possession.
All of the office work enumerated above must be done at such times as not to interfere with other jobs you may be superintending, figuring or periodically visiting. The writer makes it a rule to visit one or more jobs every morning before going to the office, spend the middle of the day in the office (say from 10 a. m. to 2 or 3 p. m.) and then visit the same or other jobs in the afternoon before going home. Of course things will come up fre-
quently that upset this routine and this plan must be changed to suit. Whatever comes up, work ' * under way ' ' must not be neglected and you must plan to take care of it all in some way.
Job Superintendence
Upon visiting the job it is a good plan to go from top to bottom of the building, taking notice of everything that is going on, whether being done by your own men, your sub-contractors, or the owners' sub-contractors. Also look at the stock piles to see that materials are 'being delivered fast enough so that there is no danger of shortage occurring, necessitating the laying off of help.
Having "taken in" everything about the work, now look up the foreman and give him your orders. If you have seen anything in your rounds of the work that is not going just right call his attention to it, letting him know what you want done, and if it is something concerning the way men are doing some piece of work, let him take it up with the men himself. By permitting the foreman to nmke all corrections with the help he can maintain a proper discipline on the work. Of course there are cases when you will see something being done so radically wrong that stock is being spoilt, or wasted rapidly, or the men 's lives or limbs are being endangered, and in such cases you should either correct things at once or stop all work, get the foreman, and with him straighten the matter out. Storming around and hollering to the help confuses them, and calling the foreman down before the help makes him small in his own and the help's eyes. If the foreman needs censure take him to one side and give it to him; never allow yourself to do so in the presence of the help, owner or architect if you can possibly avoid it.
Go Over the Job with Foreman
Having given the foreman time to straighten out any little matters you have seen that need immediate attention, I would then go over the job with him, pointing out the parts of the work that you want pushed faster or that you want taken up next, sug-
gesting (or ordering if you see fit) that this or that thing be done next, or in a certain way ; that certain shifts be made in the help ; that this or that stock be used next, or for a particular purpose. Give him directions or orders for the sub-contractors under your control, and any other orders, directions or suggestions that may seem to you to be necessary for the proper conduct and progress of the work. Then ask him if there is any sto'ck wanted, or will be wanted in a few days, which should be ordered at once. Remember that two heads are better than one, even if one of them is the foreman's. You may have thought that you saw everything, but he will undoubtedly call your attention to a number of little things wanted that escaped you altogether, that are just as necessary and important as the big things, if the work is to run smoothly and logically.
The writer frequently finds it necessary to tell the foreman to erect some particular part, or do some certain thing, at once, or within the next few days, the doing of which seems illogical to him. In this case it is probably because we want certain parts erected so that we, or a sub-contractor, may make measurements for something that has to be gotten out or made to order, and we have mapped out in our own mind about when this particular stock will be wanted, and knowing about how long it will take to get it out and deliver it, know best when the work that makes it possible to get measurements should be done. It is just as well to let the foreman know why you want work of this kind done and impress upon him the absolute necessity of its being done on or before a certain time. No one likes to do work that seems illogical, and the foreman will see the logic and necessity of the matter when explanations are made and will accomplish the results you desire with more spirit and dispatch.
You may think these latter suggestions somewhat unnecessary, but we have seen many jobs delayed because nobody gave any attention to matters that required something to be done so that measurements of special material could be obtained, until the work was practically ready for these materials, and then there would be a shifting or laying off of help and a wait of days, or even weeks, for this particular stock.
them rather than from the building itself. It is only by determining the wants of your job from the plans and by having scheduled the times at which certain things will be wanted, that you can avoid vexatious delays, assuming, of course, that you get drawing and details from the architect fast enough, and we will VTO on- record as saying that in nine cases out of ten it is your own fault if you do not.
The foreman will probably want decisions as to the exact meaning of the plans and specifications, especially in parts of them where they are a trifle vague or susceptible of a double interpretation. These matters should be gone over with a foreman carefully and a ruling and definite instructions given him by you, unless it appears to be something that should be referred to the architect for a decision. In the latter case the matter should be referred to the architect at once, and by letter if possible, and his instructions or interpretations be obtained and followed unless there is some very good reasons for disagreeing with him. In this case have the matter out with him, and after coming to an agreement give orders or directions to the foreman. All these things being looked after, it is time to move on to another job or the office and take up the matters concerning this and other jobs.
Assuming that we are back to the office again, there will be the materials to order that you and the foreman have determined are wanted. The telephone and letters soon take care of this and gejt them off your mind. Then there are details that are wanted, and you take the matter up with the architect by letter.
All details for the job should be sent to the office, not to the building. Upon receiving a detail look it over carefully; first to see that it conforms to the general plans, large scale drawings that may have been a part of the contract plan and the specifications ; second, to see that the work illustrated by the drawings is so laid out as to be practicable and make a good workmanlike job and will fit into the structure under the existing circumstances, as is intended by the architect; third, to thoroughly familiarize yourself with the detail and all that it is intended to communicate to you, so that you can explain its meaning fully
Consult the Architect
If in looking over the detail you see anything about it that is not clear, or will not work out right, or make a first-class job, or that you think is in excess of your contract plans and specifications, go to the architect at once, or at the very first opportunity, taking the drawing with you, and discuss the whole matter with him and mutually agree upon everything before leaving. If this necessitates corrections or changes in the drawings have them made by the architect. You can then take the drawing back to the office knowing what it all means, and you are ready to distribute, and correctly explain the information it contains, to all parties concerned without further delay. Adopting this course will save you from the possibility of giving wrong explanations and from later misunderstandings with the architect and others.
Having now agreed with the architect in regard to the detail it should be absolutely and faithfully followed, even though you may not see the sense and logic of it all. The architect probably sees it and, if the matters fall within your contract, it is none of your business unless he chooses to explain.
Now, if there are parts of the detail relating to several of the sub-contractors ' and to some of your own work, you should make sufficient copies to give each party concerned a drawing and have one left for the office, so that the original can go to the job to be kept there ; or better and easier still, trace from the detail only that part which concerns each particular branch of the work, with enough of the adjoining parts of other work in each case to make the copy clear as to the location of the work, and give to each sub-contractor or material man the copy intended for. him. Make a complete copy for the office unless you are fully satisfied that, after the thorough study you have given the detail, you will not need it in the office, and send the original to the job to be kept there at all times for the guidance of the foreman and all others concerned. To illustrate the point clearly, let us assume a detail through the outside wall and a window in a brick building, beginning just below the first floor level and extending above the second floor. This drawing would show in section and broken
elevations, drawn to full size, the following parts of the structure; stone or terra cotta water table or belt course; stone or terra cotta sill and lintel of window ; second story belt or cornice of stone or other material, if there happens to be one ; the window frame and sash, with sections of the sill, jamb, mullion, head, sash, stop beads, edge casings, casings, stool and apron; the base and moulding; chair rail; picture moulding; the steel beam or other lintels over windows back of stone work; the size of the brick, with thickness of mortar joints and elevation of the bond ; and even other parts not mentioned. But these are sufficient for illustration.
Now proceeding according to the second plan outlined we would take a piece of tracing paper of sufficient size to get off all that concerns the stone or terra cotta trimmings; trace the section of water table, or first story belt, showing the brick above and below it for a couple of inches; then trace the section of stone sill and lintel, showing an inch or two of the brick lines and enough of the window frame sill and head to show the connection between the parts. Next trace the section of the second story belt or cornice, also showing line of brick above and below, and make elevations of any parts necessary to fully illustrate the work shown in section, such, for instance, as the corner of sill showing raised lug, etc. Only a small part of the drawing as a whole has now been copied, but you have everything on this drawing that the cut stone man wants, and you can turn it over to him. In the same way trace section of iron lintels for the steel man, window frame and sash for the sash man, and "finish" for the finish man.
In case you are going to make a schedule of finish yourself to take figures on later, when you have all the details concerning it, take a piece of paper about 3 ft. 6 in. square, place one corner over a pattern of moulding, trace and number it No. 1. Next take another moulding, numbering it No. 2, and so on, until you have traced, one under the other, each different pattern of moulding. Now make a schedule of numbers down in the lower right hand corner, allowing room to increase the size of the schedule later, and in a place for remarks note the purpose of the moulding and kind of wood.
away in the plan drawer for this job, to be taken out a little later when the next detail showing finish comes along and other patterns are to be copied onto it. This method, as can readily be seen, takes a little time, but the labor is well spent and will save the time it has taken ten times over before the end of the job. All the sub-contractors have the information they Avant as far it goes; you have a copy of members of finish as far as detailed and you have the original for the job, where it belongs. These copies will all serve to save you telephoning and explaining, bothering the foreman and thus interfering with your work ; saves the architect's time and patience in explaining things that you should explain; overcomes the possibility and probability of misunderstandings and consequent mistakes, while greatly facilitating the getting out of the several materials and parts. You must admit that all of these benefits compensate for the trouble and time involved in making the copies.
This daily routine of visiting the various jobs; receiving the information for the work from the details; transmitting the information to all parties concerned ; purchasing the materials ; seeing that the sub-contractors get around as agreed and perform their work properly; keeping the foreman informed as to what you want done ; when you want it done, and well supplied with help, as well as with details and stock ; all stuck to persistently from the minute a contract is signed until the job is completed is sure to have results.
Guard against one thing, and that is, allowing your energy and persistence to cease when you get along toward the end of a job. By this time you are about starting, or are in the midst of other jobs and are losing interest in the one nearing completion; at least, I am assuming that you are because I always do myself. It is then that I bring all of my will power into action, determined at all hazards to visit this particular job as often, or even oftener, than before and see every single thing done, and that expeditiously, in order that I can have the time that all this is taking to devote to the other, and for the time, more interesting jobs. This almost invariably results in the jobs being done on time, and if I have succeeded in getting ahead of my schedule a little every now and then, in getting an acceptance ahead of contract time.
Handling Work at a Distance, Timekeeping and Divided Costs
In writing the above, I have assumed that the job was so located that it was possible to see it every day, or at least three or four times a week. If the building happens to be 100 or 200 miles from the office, the method of handling must be modified somewhat and how we manage such work will now be explained.
It is of course out of the question for you to see such a job daily or even several times a week. I generally plan to visit once a week work that I can readily reach and get back from in a day, getting up early in the morning so as to get a train around 6 to 6.30 A.M., thus getting to the work as early as possible. I choose for the regular weekly trip the pay day, having time taken up to 5 P.M. of the second day preceding the one on which I make my visit, so as to enable me to have all the envelopes made up in the office the day before pay day. These I take home with me the night before going to the job, so as to go direct from home to the station.
Having reached the job, I go through the same routine I have described for the daily visit to the nearby job, except that it lakes longer, as there is more to see, more to explain to the foreman and more planning ahead for future work I want done and materials that the work will require. Having established the day for this weekly visit, I make it known to everybody with whom I am doing business, sub-contractors, material dealers, etc., notifying them that if they want to see me at the building about anything to come there that day, and that if there is anything about which I want to see them there I will notify them, giving them as much notice as possible. I also try to have the architect or his representative make his visits to the work on these days. Now I let nothing, except of the utmost importance, interfere with my weekly trip. By making a long day at the job, spending a great deal of time with the foreman and subcontractors, explaining work and ordering materials as far
next visit.
Isolated work like this requires a very competent foreman ; one of the kind of men who is resourceful, of good executive ability, temperate and trustworthy. In fact, you want a man as good as yourself, and you cannot expect to find him for $18 to $20 per week. The right man is cheap at any price under $40 per week, plus board and railroad fares, if the job is of any size. If 25 or 30 men are employed, he can handle the work enough better than an ordinary foreman to save you his week's wages every day that the job lasts. If anything comes up between visiting days that cannot be settled over the telephone, which I instruct the foreman to use freely if necessary (preferably in the evening, as it does not then interfere with his or my day's work), then another trip must be made as soon as possible.
If the job is of fair size, say $25,000 or more, enough help will be employed to make a timekeeper desirable, if not an absolute necessity. I find that it is usually possible to employ some young man locally who is well vouched for and with at least a high school education, who will work for from $10 to $15 per week, making as long a day as circumstances require. If one cannot be found locally, there is always one to be found in the city who will go anywhere you want him. In addition to keeping the time he can look up freight that is arriving, arrange for teaming, chase up local sub-contractors and material men, tally and check quantities of materials, check the bills for them sent to the job from the office for this purpose before they are entered in our books to the dealer's credit, assist the foreman in laying out work, take charge of a small crew of men on some kinds of work under direction of the foreman, and so on indefinitely. In fact, it is surprising the amount of petty detail work that such a man can do if properly handled, and it serves to relieve the foreman and give him the greater part of his time right on the job with the help.
The three most important duties that I give to the timekeeper are keeping the daily journal or "log book," keeping the divided time and checking quantities of materials. For these purposes
HANDLING WORK, TIMEKEEPING, ETC. 165
I provide him with two books and fully instruct him. I give him these instructions in the presence of the foreman, and require him to perform the duties involved under the foreman's superintendence and inspection.
In the journal I have him take a page for each day, putting the date on the top line ; follow this with the weather, the number of men of each trade employed— first our own men and then those of all sub-contractors, including any employed by the owner; a complete resume of all materials received at the job and from whom ; a synopsis of the work that is being performed by our own help and all sub-contractors; make note of who visits the job, as, for instance, the architect, owner, sub-contractor, material man, inspector, superintendent, member of firm or any one, in fact, not a regular and daily visitor ; also particular record of any accident or unusual happening; in fact, any and everything that suggests itself as of possible value to me to know about, that takes place. This will consume about one hour's time, not all put in at one time, and just about fill one page of the book 14 or 15 in. long, on the average.
The value of this record may be almost worthless on one job and on the next one contain information that would win you a lawsuit ; as, for instance, the information it might contain in regard to delays by sub-contractors working for the owner or delay in delivery of material that he was to furnish; record of visits of an inspector and of some order given by him ; particulars of and names of witnesses to an accident of some kind that you might be sued for six months after the work was completed, etc. Taking so little time and liable to be of so much value, under circumstances that might arise, by all means insist upon this journal being kept if a timekeeper is employed.
The checking of bills is very important if you do not want to pay for materials not received. Brick, for example, which are purchased by the thousand delivered, coming in two-horse carts containing from 1000 to 1800 brick, are usually accompanied by duplicate slips, one to be left by the teamster with some one in authority at the job and the other to be signed by said person and returned to the party selling the brick by the teamster. With common brick costing $7 or $8 per thousand it is almost as cheap to permit yourself to be cheated out of a hundred or two
of brick to a load as to undertake to count each load, on account of the time and expense involved in doing so. To take the foreman from his work is out of the question. Here the timekeeper can be made use of by giving him a laborer or two and having a load counted now and again, especially, if upon looking at the load before it is dumped, it appears to be small for the number of brick called for by the slips. When a dealer knows that you are apt to count a load at any time and do actually do so every day or two, he will see that every cart going to your job contains full count. I do not mean to imply that all dealers take advantage of contractors in this way, but I do know that some of them do, and when in some distant place, dealing with strangers, it is worth while having the word go abroad that you are going to get what you pay for in quantity and quality.
Brick coming by cars are usually piled regularly, even if only common brick, and always if face brick. In this case, timekeeper should measure and cube the contents of the car before a brick is taken from same. It can readily be determined by the cubic contents if the car contains the number of brick called for by the bill of Jading.
In a similar manner lumber can be approximately suryeyed on the teams or cars before unloading ; sand, gravel and crushed stone checked up with accompanying slips; schedules of steel, lumber, window frames, doors, etc., checked; and all materials be checked and accounted for and practically none of the foreman's time be drawn upon to do so. All shortage, real and apparent, should be called to the attention of the "office" and the shipper immediately, so that the matter can be straightened out at once. Letters or the telephone will accomplish this. All slips received with loads should be retained by the timekeeper, and all bills for materials should be sent to the job as soon as they are received at the office, for him to check and "0. K." if they are correct. The journal and duplicate slips furnish an accurate record of materials received, and in a very little time the timekeeper will go through them all. We do not place the amount of invoices to the credit of the party selling until the bills have been checked and "0. K.'d" as above.
works per week, but the number of hours each man has on each division or class of work. For this purpose I have devised time slips, copies of which may be seen in Carpentry and Building, June, 1906, page 193. On the first morning of the "work
READY FOR USE
week," which in our case is Friday, the timekeeper makes a slip for each man employed, fills in the dates and rate of wages and puts them all on a Shannon file with those of each class of help together. Our slips are punched on the top edge to fit this file, although the illustration above referred to does not show punching.
see who are present and at what they are going to work. He
then makes several rounds of the job during the day, one being right after the noon hour and one starting in time enough before the end of the day to see what all of the men are doing and who are there at the end of the day.
Upon coming to each man on this final round he questions him as to the various divisions or classifications of the work he has been engaged upon and how many hours upon each class, entering upon the slip the hours thus obtained under their proper heading. The help are cautioned to notice the time of day if shifted from one class of work to another and the timekeeper's several trips and part that he may take in assisting the foreman at superintendence, also familiarize him with the shifts that are made during the day, and between the individual workmen and the timekeeper a very accurate resume of the day's work can be obtained and immediately entered.
Should a new man come on at any time during the week, a slip is immediately made out for him and inserted in the file with other help of his class. At the end of the week this file contains each man's total time, from which a report for the payroll can be made out, and a couple of hours' time will pick out the total number of hours and the cost in dollars and cents for each class of work for the week. Now remove the slips from the file, securing pieces of string through the holes, lay to one side and make new slips for the next week and put them on the file.
Now in the book provided for the purpose have the timekeeper record these hours and costs, each under its proper heading. The best book for this purpose is one about 10 x 14 in., with ledger ruling, two columns to a page. On the first page of the book write the heading of the class of work first encountered and under same write the word * ' labor. ' ' On the opposite page write the same heading and the word "stock." The two ledger pages will then have the appearance indicated in the reduced f ac-simile presented herewith.
Where the nature of the item is such that there will be stock or other credits, instead of using both columns for charges against the item, the right hand column may be used for * * credits, ' ' as shown on the reduced pages.
Now on this left hand, or "labor" side, both columns, enter "labor"; on the right hand, or "stock" side, one column, enter all stock, quantity and cost, immediately after checking up the bills and before sending them back to the office. Also on this
part of the cost of this class of work.
The "labor" if you choose can be subdivided several times for each class of work. As, for example, on a large factory job you might want to divide the cost of the labor under the head of "windows" into handling and setting frames, jointing in sash, stop beads and finish and applying hardware ; to enable you at completion of work on windows to more thoroughly analyze and tabulate your costs. This may readily be done by making four entries of hours for the week instead of one, adding after each entry the name of subdivision. .Before starting another heading leave room enough to make all probable entries under the classification started. Generally speaking, the two double columned pages will take care of almost any division of the work for a pretty large job.
At the completion of the job, or before, if the work under the heading is completed, the unit costs can be worked out accurately by simply adding up each column, totaling them and dividing by the known unit. Take the item of brick work ; run down through the stock side and get the total number of brick, divide total cost of labor and stock by the number of thousands of brick and you have the cost of brick per 1000 laid in the building.
If you want to analyze further it is possible to go down through the "stock" columns and pick out the quantity and cost of lime, cement, sand, stage stock, etc. In the labor column, if you have made provision to do so, you can pick out the labor of making and carrying mortar, handling and carrrying brick, building and taking down stage (unless you make this latter a separate item, which I usually do on jobs of any size), laying brick and washing and pointing. Thus you can work out the cost of 1000 brick, laid in the wall, in detail and with accuracy.
we give below costs that we have recently worked out.
Brickwork 601 M; laid from September 1 to December 20, 1907. Water struck brick 12 in. and 16 in. vaulted walls with some 12 in. and 16 in. partition walls having heat, ventilation and fireplace flues. Mortar 1 part lime, 2 parts Portland cement and sand about 6 parts.
It will be noticed from the time of the year in which part of this work was done that brick would have to be heated, also the water for mortar, and that unusual precautions would have to be taken to protect the work nights. The sundry expense item above is for fuel for this heating, canvas and boards for protection, railroad fares for imported help, etc. This price is for the brick right through, about one-fifth of the total quantity being laid in the exterior face of walls, the brick being culled to get the best for this purpose.
Stonework— Broken coursed ashlar backed with rubble. First story 2 ft. 6 in. thick ; second story 2 ft. thick. Mortar, 4 sand to 1 Portland cement, with very little lime. All stone taken from adjoining fields and farms, the maximum haul being about one mile. The only cost of stone was the labor of gathering and teaming. Stone were large field boulders split with plugs and feathers and hammer broken to shape. Total number cubic yards 704.
From these two examples will be seen the possibilities of obtaining costs if proper care is taken in keeping the divided labor and stock books. It does not seem necessary to discuss the value of this information to a contractor, but I am constrained to add that, out of all the builders in the city of Boston, I only know of four or five who make any attempt to obtain such itemized costs from their work.
In the case of items like excavation, stonework or concrete, where there is apt to be a little difference between the estimated and the actual quantity, and where the stock column does not show up the number of units, the foreman and the timekeeper should take measurements every few days while the work is going on to determine the actual quantity and enter them in the journal, so that at completion the known quantity can be used from which to analyze and tabulate the unit costs.
While the time sheets are divided into the usual classifications made when figuring upon work generally met with, if any particular job calls for some special division not made, one of those not used can be scratched out and the new one written in. In the same manner subdivision of labor on the listed items can be made ; thus over * * windows ' ' write * * frames, " " hanging, " " casing, ' ' etc.
All the information secured in this way is of vast importance. The very fact that builders generally make no attempt to work out these unit costs accounts for the wide range in their figures and the large percentage that find their way into the bankruptcy court. Both timekeeper and foreman should not underestimate the importance of keeping time slips and cost book accurately, entering everything as promptly as possible and questioning men about items of labor, stock or sundry expense if there is the least doubt in their minds as to where it belongs. When the timekeeper attends to all the duties above enumerated he will find that he is occupied every minute. A young man of the right sort, however, will become interested and learn a great deal during the six or seven months' course of a fair-sized job.
On our last large job the timekeeper was a graduate civil engineer earning $30 per week in a city of 30,000 people, and he gave up his position and came to work for us at $20 for the sake of the experience he could get in practical building con-
struction and costs in connection therewith. He made a good man for us, as he could use a transit, understood plans and could assist the foreman materially in laying out work, and he knew the local freight yards, teamsters, material dealers, etc.
On this particular job, which was 250 miles from Boston, we tried an experiment in the matter of handling the payroll, by making a deposit of several thousand dollars in a local bank and arranging for the timekeeper to draw on it by check for his payroll, freights, and sundry small bills with people with whom we did so little business that we did not want to open an account. We required all bills and payroll to be verified by the general foreman or foreman-carpenter, and every check to be countersigned by one of these two men as well as by himself.
Every week, immediately after drawing the payroll, he sent the office a copy of the payroll in detail, together with all cash expenditures for such items as carfares, oil for lanterns, postage, stationery and the like, giving us the amount and number of the check. All bills and freights he paid he sent to us at once (not waiting until reporting payroll), writing any explanation and the number of check on the face of the bill.
In the office when the first deposit was made in the local trust company the bookkeeper charged said "trust company" and credited "cash." Upon receipt of a receipted bill or a payroll report, with amount and number of check with which it was paid, the bookkeeper credited the "trust company" and charged the "job." From the weekly reports and a knowledge of expected freights we in the office were able to tell, without prompting from the timekeeper, when it was time to send more money to the trust company, and accordingly sent it. In ten months' time the trust company handled about $40,000 and there never was a difference between the books in the office and the timekeeper's cash account but once, and that was of about 40 cents. This, upon investigation, our bookkeeper found to be an interest charge for an overdraft that the timekeeper had made when we let the cash get too low.
This job was visited by the writer every two weeks, staying two days, running in an extra trip several times when something came up that made it necessary,
The building was fireproof construction (except the roof, which was mill construction), five stories high, with a ground area of 10,000 sq. ft., and we succeeded in completing same in two months and one day less than the contract time of one year, building for the same people meanwhile two smaller buildings amounting to about $8000. This was made possible by systematic handling of the job through ample stock being supplied in advance of the wants of the work ; constant reports of the progress or delays on the job by almost daily letters to the office, followed by advice, suggestions or orders from the office, sent immediately upon receipt of reports from the job.
We have perhaps touched on bookkeeping in these last few paragraphs more than anticipated when the article was commenced, but as this part of the building business is as important as any other part, we do not consider the remarks out of place. If results are to be accomplished there must be system all along the line : in estimating, working out the costs, keeping the books, purchasing the materials, letting sub-contracts, superintending the job and dealing with the owner and architect.
One thing must be guarded against, however, and that is not to have your system too cumbersome or expensive. The narrow margins in the business make it necessary to hold down to the lowest possible level the office or "overhead" expenses. The firm that can do business with an "overhead" expense of 3 or 3^ per cent, of the year 's total business has a much better chance to stay in the "game" and make profit than the concern that allows the same expense to get up to 8 or 10 per cent.
The first three pictures shown herewith relate to a wing of the Eastern Maine Insane Hospital at Bangor, the contract for the erection of which was dated August 10 and the building accepted on June 9 of the following year, the cost of the structure complete being about $165,000. The work was done in 62 days less than the contract time, but there was no bonus for completing it before the time called for by the contract. This is the building from which the examples of unit costs on brick and stonework were taken. Of the three views relating to this building, the first two show the condition of the work September 18; that is, a trifle more than a month after the contract was dated, while the third picture shows the appearance of the wing
dated.
The fourth picture shows a 24-classroom schoolhouse in the Roxbury district of Boston, which was completed in 79 days less than the contract time, the city offering a nominal bonus for finishing the work ahead of time. The contract in this case was signed March 27 and the building was accepted December 12 of the same year. The cost of the structure complete, exclusive of furniture, was $160,000.
We are now nearly at the end of our remarks, and find that we have up to this moment neglected to mention two important points that should have been touched upon before.
First— You will recall my having discussed at some length the necessity of doing some work at seemingly illogical times in order to make possible the procuring of measurements for parts of the work that require considerable time to get out. In many cases it would be physically impossible to do some parts of the work until the building was farther advanced, and at the same time it is desirable, if not absolutely necessary, to have the measurements from which to lay out and get out some special part of the work. This might be some iron stairs up through the building in a masonry well with the walls changing in thickness at different stories ; or the exact dimensions of several rooms that are going to be filled with special case work. The architect has probably given the details, but has broken the lines at a number of points, thus "putting it up to" the contractor to give absolute working figures.
In many cases of this kind that come to my notice the general contractor is waiting for the sub-contractor to assume responsibility and make figures, while the sub-contractor is waiting for the general contractor or architect to do the same thing, and the foreman hardly dares to and is waiting for some one of the first three to take the responsibility. The net result is that the measurements are not obtained until the building has nearly reached a point where the special work must be installed, and then there is a wait of days, or even weeks, for the material.
In a case of this kind the superintendent should "take the bull by the horns" and establish measurements for everybody to follow. Before doing this, study the part of the plan involved
carefully, noting fixed structural parts and put figures in ink on the working drawings at the job for every one to follow, with positive instructions to the foreman to see that the parts concerned are built to the figures made, thus becoming responsible yourself to the architect, the owner, the sub-contractor and everybody concerned for the accuracy and reliability of the information imparted. If you do not dare to assume these responsibilities, you need more training as mechanic or foreman.
Second— The building business is made up of vexatious things, and it takes courage to meet them all promptly and straighten them out. The first inclination when you hear that something is going wrong, and the architect and owner are kicking, is to keep away from them and the building until the thing straightens itself out. This is all wrong and you hurt yourself in everybody's eyes by doing so. If we hear, directly or indirectly, that something is going wrong at the job, we make it a point to get there as soon as our legs or a car can take us and find out at first hand what is the matter, and follow it right up with the architect, owner, sub-contractor or whoever may be concerned, until everything is settled, and matters left running smoothly. Having done this, we feel better, the load being off of our mind, and the architect and owner respect you for having come up like a man, faced the "music" and seen it through.
The object of this article has been to try and make clear to the reader how system of the right kind in the office, on the job, and in your own handling of both, may be obtained, getting thereby the maximum of results with the minimum of expense.
By I. P. HICKS
Presents a system of simple and practical application for estimating materials and labor chiefly as applied to suburban residential work. One of the most serviceable books for contractors and builders as well as for carpenters, who will find it to contain also a very complete treatment on framing roofs of all descriptions.
The "Guide" was designed by a man who understood the needs of the young carpenter and builder, and the knotty problems of the daily work are solved in the simplest and best ways.
By FRED T. HODGSON, Architect
The book aims to give a careful consideration to all the items and elements of cost in construction, beginning at the foundation of the building and progressing to the finished structure. Young contractors and builders especially will find it to cover the subject in a plain, practical way, with detailed consideration of cost factors, items and quantities.
There is a detailed estimate of a $5,ooo house and additions: detailed estimates of kitchen, dining room, parlor, den, halls, bedrooms, conservatory, basement, bathroom, closets, etc., all figured out and measured by the quickest and simplest methods. The author also tells how to estimate by cubing, by the square of floors or walls, and by the process of comparison, and gives hints and practical suggestions for taking measurements and making tenders for work.
By EDWARD NICHOLS
Tells how to go about making an estimate intelligently. As a practical example, a complete plan of a house is given, and the estimates of cost are worked out from this, with bills of material and working data.
By WM. ARTHUR
matter which branch of building operation you may be interested in, you are sure to find this new reference work of exceptional value. It covers everything that the contractor and builder, architect or owner has to think about from the operation of the latest building law to the figuring of overhead expenses and the insuring of work against fire, etc. There are hundreds of ways of losing money in building if one is not careful, and the information given in this book will enable you to avoid them. Much new matter on construction with specially prepared tables is included. The author has been actively engaged in the building business as architect, contractor, consulting expert and appraiser for many years and he has treated his subject simply and thoroughly. The young man just starting in business will find this book equal to years of experience.
CONTENTS
Relations Between the Contractor and the Architect; Relations Between the Contractor and the Owner or Real Estate Agent ; Relations Between the Contractor and Dealers and Subcontractors ; Relations Between the Contractor and his Workmen ; Reading Plans and Specifications ; The Preparation of Estimates ; Building Contracts ; Nature of Contracts ; General Contracting or Subletting ; Method of Work ; Buying of Material ; Best Paying Work ; Speculative Building or Ready-made Houses ; Office Equipment ; Bookkeeping; About Keeping Costs; Builders' Law; Insurance and Bonds; Hand and Machine Labor; Weights, Measures, and Their Use; Foundations; The Superstructure: (i) Walls and Masonry; (2) Floor Loads; Loads upon Posts, Columns. Lintels, Rods, and Ropes ; Concrete Forms and Work ; Construction Notes from the San Francisco Fire; A Short Chapter; Fire Loss and Safe Building; Where to Locate; The Ideal Education for a General Contractor; The High Schools, Libraries, and Tradesmen; A Little Library; Big Contracts; Miscellaneous.
IS a modern working guide for all who figure the cost of building construction, either in detail or approximately. It gives the actual time, labor and material required on every operation, in all classes of residential and municipal work, 'as recorded and checked by the author and other experts on thousands of jobs, finished under varying condi.tions, in different sections of the country. Special stress is laid on those items that are affected by varying conditions and the reasons for the difference, as found by experience, are given.
While particularly intended for the every-day use of contractors, builders, architects and engineers, this book, because of its practical nature, is indispensable to the insurance adjuster and appraiser. The new edition contains 744 pages, but by the use of thin paper is reduced to pocket size. Part I. deals with Approximate Estimating, and Part II. with Detailed Estimating. It is very comprehensive, and covers all work and materials entering into building construction. The chapter on Reinforced Concrete work gives the actual cost, writh illustrations, of all the latest types of construction used by the Aberthaw, Ferro-Concrete, Trussed Concrete Steel, Hy-Rib, Hennebique and Roebling Construction Companies, with full information as to cost of forms, quantity of material, labor required, etc.
The large amount of valuable data added on Ornamental Iron Work, Stairs, Concrete, Apartment Houses, Comparative Costs, etc., makes the new edition well worth the price, even to those who have the last previous one.
These blanks have been prepared with the idea of furnishing to contractors and builders a convenient form upon which to make an estimate and record of cost of work which they figure on and execute. Space is provided for recording all the material usually required on Residences, Schools, Stables, Garages, Apartment Houses, small Factories, and Office Buildings.
By J. C. PLANT
A practical working guide for the contractor, architect and owner. With forms and an explanation of duties and responsibilities incident to public and private contracts.
AN INITIAL FINE OF 25 CENTS
WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE.
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u1dLi8qY3ddvxOWi | Conservation | Distributed Proofreading Team at http://www.pgdp.net
CONSERVATION
BY CHARLES L. FONTENAY
_The people of Earth had every means of power
at their command, yet they used none of it. Was
it due to lack of knowledge and technique; or
was there a more subtle, dangerous reason?_
Worlds of If Science Fiction, April 1958.
The yellow sands of the spaceport stretched, glaring and empty, in
every direction. There was no sign of life from the little group of
buildings a mile away.
In the control room of the tall, round-nosed starship, technicians
labored and officers conferred while the red needles that showed rocket
tube temperatures sank slowly toward zero on their dials.
"Maybe Earth's depopulated, Tom," suggested John Gray, the executive
officer. He ran his fingers through close-cropped red hair and peered
through the port with thoughtful gray eyes.
"Hardly, John," replied Commander Tom Wallace, frowning. "The scout
rockets showed some good-sized cities, with smoke."
"I was off duty then and haven't had time to read the log," apologized
John. "What gets me is that they should have a robot-controlled
space relay station orbiting outside the atmosphere, and a deserted
spaceport. It just doesn't jibe."
"That's why we have to be just as careful as though we were landing
on an alien planet," said the commander. "We don't know what the
conditions on Earth are now. How long has it been, John?"
"Two hundred and fifty-eight years," answered John. "Ten years, our
time."
"Pick three for briefing, John. This is going to be a disappointing
homecoming for the crew, but we'll have to send out an exploration
party."
The landing ramp slid out from just above the rocket tubes, and the
armored car clanked down to the sand. John steered it across the wide
expanse of the spaceport toward the group of buildings. Above and
behind him, a woman swept the terrain with binoculars from the car's
observation turret. In the body of the car, another woman and a man
stood by the guns.
The buildings were just as lifeless when they drew near, but there
was an ominous atmosphere about them. They were windowless, of heavy
concrete. Through slits in their domed roofs, the noses of a dozen
cannon angled toward the ship.
"John, there's someone there," said the girl in the turret, tensely.
"You can't see it through the windshield, but there are some smaller
guns poking out near the ground and they're following us."
John stopped the car and switched on the loudspeaker.
"Hello, the spaceport!" His amplified voice boomed out across the sand
and reverberated against the buildings. "Is anybody there? We come in
peace."
There was no reply. The big guns still angled toward the starship, the
little ones focussed on the car.
"They may be robot-controlled," suggested Phil Maxwell, the gunner on
the side of the car toward the forts. "Any sign of an entrance, Ann?"
"Nothing but the gunports," replied the girl in the turret.
"Don't fool with them, John," said Commander Wallace, who was tuned
in from the ship on the car's communications system. "If they're
robot-controlled, they'll be booby-trapped. Move out of range and
continue with your exploration."
Two days later, the car emerged from the desert into comparatively
fertile country. The four explorers found a broken concrete highway and
followed it between rolling, treeless grasslands. Near dusk, they saw
smoke on the horizon--and ran into a roadblock.
A segment of the highway had been thrown up into a ten-foot wall,
barring their progress. Over the edge of the wall, the muzzles of
heat-guns pointed at them as they brought the car to a halt some
distance away. John got the commander on the car radio.
"We could swing around it, but we don't know whether they have
vehicles that could outrun us," he reported. "And my conception of our
mission is to establish contact."
"That's right," agreed Tom. "But stay in the car until you get a
friendly reaction. Then you're on your own--and I'm afraid you're
expendable, John."
John switched on the loudspeaker and made overtures to the roadblock.
After a moment, a lone figure stepped around the edge of the mound of
earth and concrete and approached the car slowly. The man was dressed
in the drab, baggy uniform of a professional soldier.
"If you come in peace, leave your vehicle and identify yourself,"
called the soldier. "You will not be harmed."
"Take over, Phil," ordered John. He slipped from the driver's seat and
climbed through the turret. Jumping to the ground, he approached the
soldier, his arms swinging freely at his sides.
"John Gray, executive officer of the starship Discovery, returned from
a colonizing mission to Deneb III," said John, holding out his hand.
The soldier ignored the out-stretched hand, saluting formally instead.
"Arrive in peace," he said. "If you will leave your vehicle here, you
will be escorted as deevs to Third Sarge Elfor, commander of the town
of Pebbro."
John returned to the car and held a brief consultation with his
companions. Although he was in command of the exploration party,
planetary operations of the starship's personnel were conducted on a
somewhat democratic basis. The commander listened in, but left them to
their own judgment.
"Communications blackout for a while then, commander," said John. "I
see no reason to let them know about the personal radios right now."
The quartet emerged from the car wearing small packs of emergency
rations and equipment. Behind the roadblock, the sight that met their
eyes was unexpected.
The robot-controlled space relay station, the heavily armed pillboxes
at the spaceport and the heat-guns poked across the roadblock at them,
all had made it logical to anticipate a powerfully equipped task force.
Instead, they found a troop of 19th century cavalrymen, armed for the
most part with 13th century weapons. There were no more than a dozen
heat-guns in evidence, and their bearers also carried short swords and
long-bows with quivers of arrows.
The four from the starship were given mounts and, with no outward
indications of hostility, were escorted to the town whose smoke they
had seen.
The town was another surprise. They had expected either a fortress or
an outpost of brick and log buildings. It was neither. The buildings
were tremendous cubes and domes of steel and concrete, sleek and
modern, windowed with heavy glass bricks. Skeins of cables, coils and
loops of aerials bespoke the power that must be at their command.
But the people walked.
Not a car or a truck was to be seen. Men and women in the gray
military uniforms walked or trotted up and down the broad paved
streets. Occasionally a horse-drawn wagon passed, hauling a load of
vegetables or manure. It was as though a cavalry post of the old West
carried on its slow-moving duties in a super-modern setting.
Third Sarge Elfor was a middle-aged man of military bearing, with a
sandy handle-bar mustache. He sat behind a huge desk in one of the
town's biggest buildings. There were elevators, open and deserted, in
the lobby, but they had to climb ten flights of stairs to reach his
gleaming office.
"The Topkick sends you greetings from Kansity, capital of the Earth,"
he said. "We have watched your ship since it approached the outer
atmosphere. We have listened to your communications since you left your
ship, and have been interested in the indications that you are of Earth
but unfamiliar with it. We are interested also in your use of a vehicle
that can travel for three days without refueling. But we do not find a
record of any ship named Discovery, and we do not know what you mean by
Deneb III."
"The Discovery left Earth 258 years ago," replied John. "We established
a colony on Deneb III, the third planet of the star Deneb, before
returning to Earth."
"You are the descendents of the ship's original crew, then?"
"No," said John. He explained as well as he could the extension of
subjective time at near-light speeds.
"Mmm. And you have left a colony on a planet of another star." They
could not tell from the Third Sarge's tone what he thought. After a
moment's meditation, he said:
"We shall talk again tomorrow. Tonight you are our guests and will be
accorded all courtesy as deevs. Are you husbands and wives, or shall we
billet men and women separately?"
"However it suits your convenience," answered John. "You may billet us
all together if you prefer."
Third Sarge Elfor took them at their word. They were conducted to a
single room, evidently in the heart of officers' quarters. Here again
they ran into the same anomaly that had impressed them since they
landed.
There were gleaming electric fixtures, but orderlies brought them
tallow candles as dusk fell. There was plumbing of the most advanced
order, but when they turned the taps no water came. The orderlies
brought buckets full of hot water for their baths in the bright-tiled
tub.
"I don't understand this at all, Ann," said John. He was towelling
himself vigorously, while she brushed the quartet's clothing clean
of the dust of the road. Phil lolled in luxurious undress on one of
the four beds, reading a book from the well-stocked bookcase. Fran,
preparing for her bath, was binding up her hair before a full-length
mirror. "Even the cold water doesn't run a drop."
"Plumbing gets out of order in the best of families, John," Ann
reminded him with a smile.
He glanced affectionately at her. Blue-eyed, black-haired Ann had been
John's companion in the six-months exploration of Deneb III, and their
seven-year-old son now was learning to read in the starship's school.
John and Ann clashed like flint and steel in the crowded confines of
the starship and consequently maintained no association while aspace.
But they were a happy team in the free, challenging atmosphere of a
planet.
"Electricity, too, at the same time?" he asked. "And it's not just
that. The whole place reeks of latent power and high science, but they
use an absolute minimum of it."
"I've got a partial solution to the garrison state of affairs and the
military set-up, anyhow," said Phil from the bed. "They've had a war
since we've been gone."
"That's no surprise," commented Fran. Chubby, blonde Fran and dark,
stocky Phil had been companions for a year aboard the Discovery. They
had volunteered jointly for the exploration mission. "They should have
had several of them in 250 years."
"This was an interplanetary war," retorted Phil mildly. "Or rather, it
wasn't war, but occupation of the Earth by the enemy. The Jovians were
smart enough not to attack Earth directly, but threw their strength
at the crucial moment behind the weaker side in the war between
Eurasia and the American Alliance. Then they moved in to take over the
war-weakened victors."
"The classic role of the strong neutral," commented John drily. "What
were the Jovians like?"
"Evidently everybody on Earth knew from first-hand experience when
this book was written a century ago. There are no descriptions and
no illustrations. There are some hints, though: methane-breathing,
cold-loving. They had domed, refrigerated cities."
"What are you reading--a history book?" asked Ann curiously.
"Yes, it's the newest book of the whole lot, and the only one that
isn't brittle and dog-eared. At that, it's the worst-made book of them
all. It looks like it was printed on a hand-press and bound by hand."
"Pioneers, oh pioneers!" trilled Fran softly. "But what are they doing
in the midst of all this technology?"
Supper in the officers' mess was a glittering affair in the military
tradition. Their conversation developed some new revelations. Third
Sarge Elfor was commander of the whole area that surrounded Pebbro
for hundreds of miles, including the abandoned spaceport. The Topkick
was ruler of the nation, and the nation was the top echelon in a
co-operating hierarchy of countries of the world. For some reason, the
simplified terms for enlisted men's grades had replaced higher ranks in
Earth's military systems: such titles as "sarge" and "topkick." Inquiry
developed that none of the officers was familiar with such designations
as "captain" and "commander."
"But why is the spaceport deserted?" asked Phil. "Is space travel at
such a low ebb on Earth now?"
"You are mistaken in thinking the port deserted," replied Elfor. "The
big guns in the pillboxes are zeroed on your ship. If it tries to blast
off, it will be destroyed."
There was no enmity in his tone, no threat. It was a simple statement
of fact. He didn't elaborate, and the four from the starship discreetly
asked no more about it.
After the meal, they retired with Elfor and several members of his
staff to a quiet lounge. Like every other place they had seen in the
building, it was lit with candelabra. They relaxed in comfortable,
leather-covered chairs and the men enjoyed the long-forgotten luxury
of good cigars. White-aproned servitors brought them wine in fragile,
long-stemmed glasses.
"You asked about space travel from Earth," said Elfor. "Yes, you might
call it at a low ebb. Yours is the first ship to blast down in fifty
years, except the scout ships in the Jupiter sector.
"It is such an unusual occurrence that the Topkick is being informed
daily of developments. When the men of your starship have been assured
of our peaceful intentions, it will be hangared underground and the
personnel quartered here until further orders from the Topkick.
Meanwhile, you are the deevs of the hour and we shall drink to your
return to Earth."
He stood and raised his glass. They all arose. The glasses clinked
together.
"Conserve!" shouted the Third Sarge and gulped his wine.
It was a warm moment. For the first time, John felt the genuine glow,
the thrill of homecoming, as he and Phil drained their glasses and
performed the ancient rite of the spacemen when he sets foot on Earth
once more. As in one motion, they hurled the empty glasses through the
open door, to smash to pieces against the farther wall of the adjoining
corridor. There was a second crashing tinkle on the heels of the first
as the glasses of the women followed them closely.
It was only when he turned back to Elfor, his face alight, that John
realized something was wrong. The Third Sarge stood with his mouth open
in astonishment. There was something of horror on the faces of the
other Earthmen. Dead silence hung in the room.
"Sleep in peace," said Elfor at last, in a strained voice. He turned on
his heel and left the room. The staff members followed, coldly.
"Well, what do you make of that?" asked John, turning to the others
with outspread hands. "Do you suppose those glasses were valuable
heirlooms or something?"
"They looked like ordinary wine-glasses to me," said Fran. "I don't get
it, but it looks like we slipped up somewhere."
The orderly who escorted them to their room cast an occasional
side-long glance, full of awe, at them. Their heat-guns had been taken
from their room.
"I don't know what we're in for, Tom," John said gravely into his
pocket transmitter when he had tuned in to the ship. "This place is the
biggest mess of contradictions I ever ran into. You'd think from the
way they live that it's a decadent society living on the ruins of a
former civilization.
"The perplexing thing is that they obviously have power and know how to
use it, but don't."
"Your job is to find the motivation, John," replied the commander.
"Remember, we couldn't understand the underground living habits of the
Deneb IV natives until we lost half a search party in one of their
semi-annual meteor showers. Do you have any recommendations for the
ship?"
"I'd advise you blasting off and taking an orbit," answered John, "but
every gun at the spaceport is trained on the ship. I wouldn't take any
chances that they don't have atomic weapons. Despite these swords and
spears, we've seen several regulation heat-guns around here."
"It might interest you to know that they're keeping us awake aboard
with a battery of spotlights on us all night," said Tom drily.
"Spotlights." John swore softly. "And all we have to see by are
candles!"
They didn't sleep well that night. They had the distinct impression
that armed guards clanked by occasionally outside in the corridor.
There was no indication that they were prisoners the next day, however.
Third Sarge Elfor and the other officers were cordial at breakfast and
lunch, although they caught some quizzical glances directed at them
from time to time. Their movements were not hampered. They were given
the run of the town.
After noon their armored car was brought in, hauled by four teams of
horses. Flanked by a troop of soldiers, it was pulled around a corner
and vanished from their sight.
"If they're so curious about how it runs, why aren't they quizzing us
instead of letting us go on a sight-seeing tour?" wondered Ann, staring
after the disappearing vehicle.
"I've built up a theory on these Earthmen...." began Phil. But he was
interrupted as an officer and a squad of soldiers approached them. The
officer saluted smartly.
"Deev John Gray, Third Sarge Elfor sends greetings and desires that you
confer with him. The others will be free to continue their inspection
of the military city of Pebbro."
"Very well," agreed John. "Ann, you'd better come along with me to take
notes on the conference. We'll see you two tonight, if not sooner."
He motioned to the officer to lead the way, and the group went up the
street, leaving Phil and Fran standing in the shadow of a towering
building.
"What's your theory, Phil?" asked Fran.
"Simple," he answered. "The Jovian war wiped out civilization. They've
just climbed back up part of the way, but they still don't know how to
operate the machinery and use the power they have available."
"I don't know about that," said Fran doubtfully. "They seem to know
how to handle those cannon and searchlights at the spaceport all right."
"Automatic control, probably, or--" Phil paused. He was peering through
a barred window at street level. "Say, Fran, look here! Unless I miss
my guess, this is a central power station!"
Fran stooped to look.
"I think you're right," she said. "But it's deserted."
"Proof of my theory," he said triumphantly. "Now, if we can just find a
door somewhere...."
John and Ann had been back from a very routine conference with Elfor
for more than an hour, and were enjoying the informality of the
officers' cocktail lounge in their building. They were aroused by
a commotion in the street outside and, along with several off-duty
officers in the lounge, ran to the window to see what was up.
Phil and Fran, seated in a military jeep, were surrounded by excited
soldiers. Some sort of argument was in progress, and John and Ann heard
the word "credentials" mentioned.
Just as several of the soldiers, with drawn swords, dragged the
couple from the jeep, one of the officers from the lounge hurried to
the scene. The soldiers stood aside and saluted. There was a heated
discussion, with much gesticulating, then Phil and Fran were released
and headed for the lounge.
The officer got into the jeep and shifted gears. All the soldiers
whipped out their swords and stood rigid, presenting arms, as he drove
it to the curb at the opposite side of the street. Then he turned off
the engine and got out. A guard was posted around it, and a little
later a team of horses arrived to pull it away.
"How did you people get into such a predicament?" asked John when the
show was over and the four of them were enjoying drinks.
"Oh, I don't think it was as serious as it looked," said Phil lightly.
"We ran across a whole garage full of jeeps. We drove that one all
over town before this gang stopped us and wanted to see our written
authority for driving it. Everybody else saluted us. That's the
military mind for you."
"Didn't it occur to you that their objections might be something other
than mere military regulations?" asked John in some asperity.
"Phil has a theory--" began Fran, but Phil silenced her with a shake of
the head.
"My theory can wait until I have proof for it, and I expect that in
short order," said Phil, winking at Fran. "We've made good use of our
time while you and Ann were in conference."
Phil and Fran were eager to know what John and Ann had learned from
their conference with Elfor.
"Not much," he confessed. "Elfor is pretty close-mouthed. He's more
anxious to learn about us than to give us information about their
set-up.
"We did find out, though, that they've located the records of the
Discovery's departure in the archives of Kansity. There seems to be
something irregular about it, but I couldn't get Elfor to go into
detail."
The first hint John and Ann had of Phil's method of proving his theory
was when he quietly stripped and went into the bathroom as they were
preparing for supper that evening. Ann was about to remind him he had
forgotten to get the orderly to bring his bath water, when they heard
the sound of a shower roaring. All three crowded to the door, to find
Phil luxuriating under a steaming downpour.
"What goes on here?" demanded John. "Phil, how did you know they'd
started the water pumps?"
Phil smiled triumphantly.
"Try the lights," he suggested.
The others trooped back into the bedroom and Ann flicked the switches.
White light blazed in the room, overpowering the feeble gleam of the
candles.
"What is this, Fran?" asked John. "You were with Phil."
"We found proof of Phil's theory that these people just don't know how
to operate their own machinery," replied Fran happily. "We found their
main pumping station. It was in good shape, and it didn't take us long
to get the engines started and the main switches thrown."
The electric lights suddenly faded and died, leaving them in
candle-light again. At the same time, the sound of the shower gurgled
to a stop in the bathroom. Phil appeared at the door with a towel,
dripping.
"Don't tell me their machinery's given out so soon," he growled.
"Phil, this is no time to talk about discipline," snapped John angrily,
"but you and Fran probably have pulled something a lot worse than the
jeep this time. Neither of you is qualified in social psychology, but
even so you should have been able to read the signs that they do know
how to operate their machines. For some reason, they just don't operate
them."
In less than five minutes, Third Sarge Elfor appeared at their door
with a squad of armed men. All of these soldiers carried heat-guns.
"Two of you were observed in the vicinity of the power station today,"
said Elfor. "You are warned that you are suspected of having activated
the power supply of the military city of Pebbro."
"We don't deny that," admitted John carefully. "We are ignorant of your
customs, and hope no harm has been done."
"Your claim to ignorance will be determined at a formal hearing,"
retorted Elfor sternly. "We have given you the benefit of every doubt
and treated you as honored deevs. I regret that this makes it necessary
that all of you be placed under arrest. Your meal will be served to you
in your quarters."
As soon as Elfor had gone, leaving armed guards outside their door,
John tuned in the starship on his pocket transmitter.
"I would have advised against Phil's action, in view of our lack of
understanding of the situation," he reported to Commander Wallace. "But
I confess I wouldn't have anticipated that the result would be so
extreme.
"I can't fathom their reactions, Tom. In a crazy sort of way, I suppose
they fit in with all the other contradictions of their social set-up.
Have you had any luck with the ship's calculator?"
"Not enough data," answered Tom. "Maybe this new stuff will help, and
you might scrape for everything else you can transmit. I'd hate to try
a rescue operation, because that might force us to head back for Deneb
III. But if they don't decide to blast the ship in the next hour or so,
there's a chance we can pull out of this trap at our end."
John did not ask for details, for he knew their conversation probably
was monitored.
The four of them sat up half the night poring over the books in their
room. They gleaned nothing except from the "history" Phil had been
reading the night before. Unfortunately, it was not a general history,
but the flowery story of a high military family. The sort of references
they found were, "after the Jovian invaders had been driven from Earth"
and "Second Sarge Vesix participated in the bombardment that destroyed
the Jovian tyrants." No details.
What did emerge from their study was a picture of the rise of a
military aristocracy on the ashes of an earlier civilization which had
been ground to pieces under the heels of alien rulers.
There was good news from the starship at dawn.
"We're orbiting," said Commander Wallace with quiet pride. "Shortly
after I talked with you last night, they called on us to surrender or
be blasted. I asked time for a conference of officers and promised to
fire a rocket from the nose if we decided to surrender.
"I fired the rocket all right, but it was an instantaneous smoke
screen rocket. I still don't know whether their guns are manned or
robot-controlled, but I gambled that their firing was keyed to the
sight of the ship blasting off instead of to vibration. We were half
a mile up before they could swing into action, and we didn't get a
scratch."
A rescue mission with one of the scout rockets was too risky against
the strong forces of the Earthmen. Tom mentioned that fast planes had
followed them into the stratosphere. But one thing was done for the
imprisoned four.
Soon after breakfast, they were taken under guard to a Spartan
courtroom, presided over by Third Sarge Elfor.
"We have received a warning from your colleagues," Elfor said grimly.
"They broadcast to us a short time ago that if harm came to you, this
city and others will be destroyed before they leave the solar system.
In case you knew of this and it has in any way raised your hopes, I
wish to remind you that Earth's cities have been destroyed before. This
threat will not affect our decision to mete strict justice to you.
"You are charged with being enemies of the people of Earth, and with
having landed on Earth under false colors with the intent of sabotage
and espionage. Your prosecutor will be Fifth Tech Jatoo, representing
the nations of Earth. You will be permitted to speak in your own
defense."
Jatoo was a slender, thin-faced man with the air of an experienced
attorney.
"The governments of Earth make these charges against the joint
defendants," he began matter-of-factly: "That they are members of a
rebellious and traitorous group who are allied with the Jovians and
maintain an illegal, secret base on some planet or moon of the solar
system; that they came here under the guise of strangers, with the
specific intent of espionage and sabotage of Earth's defense against
the Jovian enemy; and that they actually began such operations.
"We shall present the following major evidence in support of these
charges:
"First, that the defendants did travel from the Numex spaceport to the
military town of Pebbro in a vehicle, the motive power of which is
still unknown but which obviously must utilize fuel, in violation of
the conservation laws;
"Second, that the defendants' colleagues did not approach the peoples
of Earth in peace, but remained enfortressed in an armed space vessel;
"Third, that the defendants Phil Alcorn and Fran Golden did throw the
switches activating the electrical system and powered water system of
the military town of Pebbro, that the above-named two defendants did
utilize a military power vehicle for pleasure purposes and that all the
defendants did unnecessarily destroy glass drinking vessels, all in
violation of the conservation laws;
"And, fourth, that the starship Discovery, listed in ancient records as
having departed on a colonizing mission to the third planet of the star
Deneb, was not scheduled to return to Earth for another seventy-five
years and therefore could not be the ship in which the defendants
arrived, as claimed."
Elfor inclined his head toward the quartet from the starship, who sat
behind a long table on the side of the room opposite Jatoo.
"You may state what your defense will be," he said.
"Our defense to the first three items of evidence," answered John, who
had been taking notes, "is that we have been absent from Earth for
more than 250 Earth-years and that we were, and are, ignorant of your
laws and customs. Thus, we are innocent of intent to violate them. Our
defense to the fourth item of evidence is that certain improvements
were made in the engines of the starship Discovery while colonization
of Deneb III was in progress, making it possible for us to return to
Earth ahead of schedule. Our defense to all three charges made against
us is that they are false."
It was a monotonous trial, with a parade of witnesses brought to the
stand by Jatoo, all of whom testified to seeing the defendants perform
one or more acts of "unconservation."
"In the courts of Earth, a case can be decided only on the evidence
presented," said Third Sarge Elfor when John had offered his brief
defense for the quartet. "The defendants have presented no evidence,
only argument. The fact that the defendants' clothing corresponds
to that in use two and a half centuries ago cannot be considered
competent, as it could be copied easily.
"For the safety of Earth, the defendants are found guilty and remanded
for immediate execution. In view of the existence of doubt as to
their treasonable intent and their previous status as deevs, they are
accorded the honor of death by power weapons. Conserve!"
Shocked and silent, the four were led to a courtyard outside. As they
walked, John switched on his pocket transmitter with a casual, almost
unnoticeable gesture, and murmured a report to the ship.
"I'm sorry, John," said the commander, his voice tense with emotion.
"There's no possibility of rescue, and I know it's small satisfaction
to you that your deaths will be avenged."
The quartet's hands were bound behind them and they were lined up
against a wall. The Third Sarge, attended by a good-sized retinue,
stood at ease nearby, smoking a cigar, to direct the execution
personally.
"'Power weapons' to them apparently mean regulation heat-guns,"
remarked Phil, almost jocularly. "That's what the fellow has."
A soldier was standing square in the center of the courtyard, a pistol
dangling from his grip. At a signal from Elfor, he lifted it.
"Looks like I'm first," said John, bracing himself. "Be seeing you,
somewhere."
He gritted his teeth for the wave of unbearable heat that was sure
to come. Instead, there was a silent explosion in the midst of the
courtyard and the soldier who had held the gun writhed on the ground,
incinerated.
"John! The gun exploded!" cried Phil in amazement. "I've only seen
that happen once before!--Remember that crewman who wouldn't take the
trouble to keep his gun clean?"
John was thinking fast.
"I remember," he said in a low voice. His heart was still racing from
the reaction of his near brush with death. "There's a pattern here. If
I could only get a chance to talk over things sensibly with this Third
Sarge...."
There was great excitement among the soldiery. Several of the men were
crowded around the corpse of the marksman. Elfor stood nervously, his
hand on his own holstered gun.
"They're concealing weapons," he barked to his aides. "Search them!"
A squad of guards swarmed over the four prisoners. There was an excited
twitter when they discovered the pocket transmitters. They removed the
little packets, snapping the aerial wires, and carried them to Elfor.
He glanced at them, took one in his hand, and ordered:
"Execute them!"
Another guard with a heat-gun took his position in the center of the
courtyard. He handled the weapon somewhat gingerly, but checked its
mechanism and prepared to follow orders.
He waited for the command from Elfor. But the Third Sarge now was
staring hard at the little transmitter in his hand. Instead of ordering
the guard to fire, he strode across the courtyard and thrust the tiny
radio before John's face.
"Is this true?" he demanded. He pointed at the well-known symbol
stamped on the packet, the red diagram of an atom that warned against
opening the lead-shielded mechanism without precaution.
"You mean, is it atomic-powered?" asked John. "Yes it is."
"It is a weapon?"
"No, it's a radio transmitter."
"But it operates?"
"Certainly it operates. Why in thunder do you think I'd be carrying a
useless transmitter?"
"It has been many years since this sign was seen on a working mechanism
on Earth," said Elfor soberly. "You are familiar, then, with atomic
power?"
"I'm not an atomic technician," answered John carefully, "but there
are several on the Discovery who can build anything from one of these
little transmitters to the engines of a spaceship, with the proper
equipment."
The Third Sarge stood in silent thought for several minutes. He
was high in the councils of his country, or he would not have been
commander of the zone that guarded Numex spaceport. He knew the reason
for the basic slogan "Conserve!" and he knew, as 99 per cent of his
subordinates did not, what circumstances would make that slogan
meaningless.
"Guard!" he growled. "Unbind the deevs! John Gray, come with me in
peace."
"You'd better give me back that transmitter, first," suggested John
drily. "I'd hate to escape execution just to get H-bombed by my own
ship."
It was the next afternoon that the four were escorted by a
trim-uniformed guard of honor across the flat spaceport to the
Discovery.
"The Jovians wanted to reduce Earth to colonial status, to be exploited
for its natural resources," John explained to his companions as they
walked. "All atomic installations were destroyed, all technicians and
scientists exterminated systematically and all scientific books burned.
They were very thorough about it.
"The successful revolt was accomplished with a concealed stock-pile
of atomic weapons. Since that time, they've been garrisoned against
the return of the Jovians. But atomic power was gone and so were
the scientists who could bring it back and the books from which new
scientists could learn.
"It's because they can't replace even so small a thing as an electric
light bulb that destruction or unnecessary use of any sort of equipment
is the rankest sort of treason. They've been saving all their
technological capital for a last-ditch stand against the expected
invasion.
"And it was their faulty, groping sort of maintenance that saved our
lives, because even a heat-gun deteriorates in 150 years. That gun
hadn't been fired since the Revolt!"
"Then we can be their salvation?" suggested Phil.
"Yes. The scientists who built the Deneb colony can rebuild the
technology of our own Earth. It will take a long time ... there'll have
to be schools and we'll all have to work hard ... but maybe some of us
will be able to go back, in 30 or 40 years, say, when the Discovery
can return to Deneb."
They were nearing the ship, and John saw the officers crowding the main
port, watching them come.
"It's sort of inconsequential, I know," said Ann then. "But several
times the Third Sarge referred to us as 'deevs.' Did he mention to you
what a deev is?"
John smiled.
"It's an ancient military slang term, just like 'sarge' and 'topkick,'"
he replied. "'Deev' is just plain old D.V. Distinguished Visitor. And I
suppose we are, at that." | 7,250 | common-pile/project_gutenberg_filtered | 60462 | project gutenberg | project_gutenberg-dolma-0011.json.gz:1623 | https://www.gutenberg.org/ebooks/60462.txt.utf-8 |
Vm_FHcJ7JIbjIe87 | 9.3: Cardiovascular Assessment | 9.3: Cardiovascular Assessment
A thorough assessment of the heart provides valuable information about the function of a patient’s cardiovascular system. Understanding how to properly assess the cardiovascular system and identifying both normal and abnormal assessment findings will allow the nurse to provide quality, safe care to the patient.
Before assessing a patient’s cardiovascular system, it is important to understand the various functions of the cardiovascular system. In addition to the information provided in the “Review of Cardiac Basics” section, the following images provide an overview of the cardiovascular system. Figure \(\PageIndex{1}\) [1] provides an overview of the structure of the heart. Note the main cardiac structures are the atria, ventricles, and heart valves. Figure \(\PageIndex{2}\) [2] demonstrates blood flow through the heart. Notice the flow of deoxygenated blood from the posterior and superior vena cava into the right atria and ventricle during diastole (indicated by blue coloring of these structures). The right ventricle then pumps deoxygenated blood to the lungs via the pulmonary artery during systole. At the same time, oxygenated blood from the lungs returns to the left atria and ventricle via the pulmonary veins during diastole (indicated by red coloring of these structures) and then is pumped out to the body via the aorta during systole. Figure \(\PageIndex{3}\) [3] demonstrates the conduction system of the heart. This image depicts the conduction pathway through the heart as the tissue responds to electrical stimulation. Figure \(\PageIndex{4}\) [4] illustrates the arteries of the circulatory system, and Figure \(\PageIndex{5}\) [5] depicts the veins of the circulatory system. The purpose of these figures is to facilitate understanding of the electrical and mechanical function of the heart within the cardiovascular system.
Assessing the cardiovascular system includes performing several subjective and objective assessments. At times, assessment findings are modified according to life span considerations.
Subjective Assessment
The subjective assessment of the cardiovascular and peripheral vascular system is vital for uncovering signs of potential dysfunction. To complete the subjective cardiovascular assessment, the nurse begins with a focused interview. The focused interview explores past medical and family history, medications, cardiac risk factors, and reported symptoms. Symptoms related to the cardiovascular system include chest pain, peripheral edema, unexplained sudden weight gain, shortness of breath (dyspnea), irregular pulse rate or rhythm, dizziness, or poor peripheral circulation. Any new or worsening symptoms should be documented and reported to the health care provider.
Table \(\PageIndex{1}\) outlines questions used to assess symptoms related to the cardiovascular and peripheral vascular systems. Table \(\PageIndex{2}\) outlines questions used to assess medical history, medications, and risk factors related to the cardiovascular system. Information obtained from the interview process is used to tailor future patient education by the nurse. [6] , [7] , [8]
| Symptom | Question |
Follow-Up Safety Note: If findings indicate current severe symptoms suggestive of myocardial infarction or another critical condition, suspend the remaining cardiovascular assessment and obtain immediate assistance according to agency policy or call 911. |
|---|---|---|
| Chest Pain | Have you had any pain or pressure in your chest, neck, or arm? |
Review how to assess a patient’s chief complaint using the PQRSTU method in the “
Health History
” chapter.
|
|
Shortness of Breath
( Dyspnea ) |
Do you ever feel short of breath with activity?
Do you ever feel short of breath while sleeping? Do you feel short of breath when lying flat? |
What level of activity elicits shortness of breath?
How long does it take you to recover?
Have you ever woken up from sleeping feeling suddenly short of breath
How many pillows do you need to sleep, or do you sleep in a chair ( orthopnea )? Has this recently changed? |
| Edema |
Have you noticed swelling of your feet or ankles?
Have you noticed your rings, shoes, or clothing feel tight at the end of the day? Have you noticed any unexplained, sudden weight gain? Have you noticed any new abdominal fullness? |
Has this feeling of swelling or restriction gotten worse?
Is there anything that makes the swelling better (e.g., sitting with your feet elevated)? How much weight have you gained? Over what time period have you gained this weight? |
| Palpitations |
Have you ever noticed your heart feels as if it is racing or “fluttering” in your chest?
When did palpitations start? Have you previously been treated for palpitations? If so, what treatment did you receive? |
|
Dizziness
( Syncope ) |
Do you ever feel light-headed?
Do you ever feel dizzy? Have you ever fainted? |
Can you describe what happened?
Did you have any warning signs? Did this occur with position change? |
| Poor Peripheral Circulation |
Do your hands or feet ever feel cold or look pale or bluish?
Do you have pain in your feet or lower legs when exercising? |
What, if anything, brings on these symptoms?
How much activity is needed to cause this pain? Is there anything, such as rest, that makes the pain better? |
| Calf Pain | Do you currently have any constant pain in your lower legs? | Can you point to the area of pain with one finger? |
Objective Assessment
The physical examination of the cardiovascular system involves the interpretation of vital signs, inspection, palpation, and auscultation of heart sounds as the nurse evaluates for sufficient perfusion and cardiac output.
For more information about assessing a patient’s oxygenation status as it relates to their cardiac output, visit the “ Oxygenation ” chapter in Open RN Nursing Fundamentals .
Equipment needed for a cardiovascular assessment includes a stethoscope, penlight, centimeter ruler or tape measure, and sphygmomanometer . [10]
Evaluate Vital Signs and Level of Consciousness
Interpret the blood pressure and pulse readings to verify the patient is stable before proceeding with the physical exam. Assess the level of consciousness; the patient should be alert and cooperative.
As a general rule of thumb, findings of systolic blood pressure in adults less than 100,or a pulse rate less than 60 or greater than 100,require immediate follow-up. For more information on obtaining and interpreting vital signs, see the “ General Survey ” chapter. Keep in mind that excessive drowsiness, restlessness, or irritability can be symptoms of hypoxia.
Inspection
- Skin color to assess perfusion. Inspect the face, lips, and fingertips for cyanosis or pallor. Cyanosis is a bluish discoloration of the skin, lips, and nail beds and indicates decreased perfusion and oxygenation. Pallor is the loss of color, or paleness of the skin or mucous membranes, as a result of reduced blood flow, oxygenation, or decreased number of red blood cells. Patients with light skin tones should be pink in color. For those with darker skin tones, assess for pallor on the palms, conjunctiva, or inner aspect of the lower lip.
- Jugular Vein Distension (JVD) . Inspect the neck for JVD that occurs when the increased pressure of the superior vena cava causes the jugular vein to bulge, making it most visible on the right side of a person’s neck. JVD should not be present in the upright position or when the head of bed is at 30-45 degrees.
- Precordium for abnormalities. Inspect the chest area over the heart (also called precordium ) for deformities, scars, or any abnormal pulsations the underlying cardiac chambers and great vessels may produce.
-
Extremities:
- Upper Extremities: Inspect the fingers, arms, and hands bilaterally noting Color, Warmth, Movement, Sensation (CWMS). Alterations or bilateral inconsistency in CWMS may indicate underlying conditions or injury. Assess capillary refill by compressing the nail bed until it blanches and record the time taken for the color to return to the nail bed. Normal capillary refill is less than 3 seconds. [11]
-
Lower Extremities:
Inspect the toes, feet, and legs bilaterally, noting CWMS, capillary refill, and the presence of peripheral edema, superficial distended veins, and hair distribution. Document the location and size of any skin ulcers.
- Edema: Note any presence of edema. Peripheral edema is swelling that can be caused by infection, thrombosis, or venous insufficiency due to an accumulation of fluid in the tissues. (See Figure \(\PageIndex{6}\) [12] for an image of pedal edema.) [13]
- Deep Vein Thrombosis (DVT) : A deep vein thrombosis (DVT) is a blood clot that forms in a vein deep in the body. DVT requires emergency notification of the health care provider and immediate follow-up because of the risk of developing a life-threatening pulmonary embolism . [14] Inspect the lower extremities bilaterally. Assess for size, color, temperature, and for presence of pain in the calves. Unilateral warmth, redness, tenderness, swelling in the calf, or sudden onset of intense, sharp muscle pain that increases with dorsiflexion of the foot is an indication of a deep vein thrombosis (DVT). [15] See Figure \(\PageIndex{7}\) [16] for an image of a DVT in the patient’s right leg, indicated by unilateral redness and edema.
Auscultation
Heart Sounds
Auscultation is routinely performed over five specific areas of the heart to listen for corresponding valvular sounds. These auscultation sites are often referred to by the mnemonic “APE To Man,” referring to Aortic, Pulmonic, Erb’s point, Tricuspid, and Mitral areas (see Figure \(\PageIndex{8}\) [17] for an illustration of cardiac auscultation areas). The aortic area is the second intercostal space to the right of the sternum. The pulmonary area is the second intercostal space to the left of the sternum. Erb’s point is directly below the aortic area and located at the third intercostal space to the left of the sternum. The tricuspid (or parasternal) area is at the fourth intercostal space to the left of the sternum. The mitral (also called apical or left ventricular area) is the fifth intercostal space at the midclavicular line.
Auscultation usually begins at the aortic area (upper right sternal edge). Use the diaphragm of the stethoscope to carefully identify the S1 and S2 sounds. They will make a “lub-dub” sound. Note that when listening over the area of the aortic and pulmonic valves, the “dub” (S2) will sound louder than the “lub” (S2). Move the stethoscope sequentially to the pulmonic area (upper left sternal edge), Erb’s point (left third intercostal space at the sternal border), and tricuspid area (fourth intercostal space. When assessing the mitral area for female patients, it is often helpful to ask them to lift up their breast tissue so the stethoscope can be placed directly on the chest wall. Repeat this process with the bell of the stethoscope. The apical pulse should be counted over a 60-second period. For an adult, the heart rate should be between 60 and 100 with a regular rhythm to be considered within normal range. The apical pulse is an important assessment to obtain before the administration of many cardiac medications.
The first heart sound (S1) identifies the onset of systole, when the atrioventricular (AV) valves (mitral and tricuspid) close and the ventricles contract and eject the blood out of the heart. The second heart sound (S2) identifies the end of systole and the onset of diastole when the semilunar valves close, the AV valves open, and the ventricles fill with blood. When auscultating, it is important to identify the S1 (“lub”) and S2 (“dub”) sounds, evaluate the rate and rhythm of the heart, and listen for any extra heart sounds.
Listen to a normal S1/S2 sound. It may be helpful to use earbuds or a headphone:
Query \(\PageIndex{1}\)
Auscultating Heart Sounds
- To effectively auscultate heart sounds, patient repositioning may be required. Ask the patient to lean forward if able, or position them to lie on their left side.
- It is common to hear lung sounds when auscultating the heart sounds. It may be helpful to ask the patient to briefly hold their breath if lung sounds impede adequate heart auscultation. Limit the holding of breath to 10 seconds or as tolerated by the patient.
- Environmental noise can cause difficulty in auscultating heart sounds. Removing environmental noise by turning down the television volume or shutting the door may be required for an accurate assessment.
- Patients may try to talk to you as you are assessing their heart sounds. It is often helpful to explain the procedure such as, “I am going to take a few minutes to listen carefully to the sounds of blood flow going through your heart. Please try not to speak while I am listening, so I can hear the sounds better.”
Extra Heart Sounds
Extra heart sounds include clicks, murmurs, S3 and S4 sounds, and pleural friction rubs. These extra sounds can be difficult for a novice to distinguish, so if you notice any new or different sounds, consult an advanced practitioner or notify the provider. A midsystolic click , associated with mitral valve prolapse, may be heard with the diaphragm at the apex or left lower sternal border.
A click may be followed by a murmur. A murmur is a blowing or whooshing sound that signifies turbulent blood flow often caused by a valvular defect. New murmurs not previously recorded should be immediately communicated to the health care provider. In the aortic area, listen for possible murmurs of aortic stenosis and aortic regurgitation with the diaphragm of the stethoscope. In the pulmonic area, listen for potential murmurs of pulmonic stenosis and pulmonary and aortic regurgitation. In the tricuspid area, at the fourth and fifth intercostal spaces along the left sternal border, listen for the potential murmurs of tricuspid regurgitation, tricuspid stenosis, or ventricular septal defect.
Listen to a heart murmur caused by mitral valve regurgitation:
Query \(\PageIndex{2}\)
S3 and S4 sounds, if present, are often heard best by asking the patient to lie on their left side and listening over the apex with the bell of the stethoscope. An S3 sound, also called a ventricular gallop , occurs with fluid overload or heart failure when the ventricles are filling. It occurs after the S2 and sounds like “lub-dub-dah,” or a sound similar to a horse galloping. The S4 sound, also called atrial gallop , occurs immediately before the S1 and sounds like “ta-lub-dub.” An S4 sound can occur with decreased ventricular compliance or coronary artery disease. [18]
Listen to a S3 ventricular gallop:
Query \(\PageIndex{3}\)
Listen to a S4 atrial gallop:
Query \(\PageIndex{4}\)
A pleural friction rub is caused by inflammation of the pericardium and sounds like sandpaper being rubbed together. It is best heard at the apex or left lower sternal border with the diaphragm as the patient sits up, leans forward, and holds their breath.
Carotid Sounds
The carotid artery may be auscultated for bruits . Bruits are a swishing sound due to turbulence in the blood vessel and may be heard due to atherosclerotic changes.
Palpation
Palpation is used to evaluate peripheral pulses, capillary refill, and for the presence of edema. When palpating these areas, also pay attention to the temperature and moisture of the skin.
Pulses
Compare the rate, rhythm, and quality of arterial pulses bilaterally, including the carotid, radial, brachial, posterior tibialis, and dorsalis pedis pulses. Review additional information about obtaining pulses in the “ General Survey ” chapter. Bilateral comparison for all pulses (except the carotid) is important for determining subtle variations in pulse strength. Carotid pulses should be palpated on one side at a time to avoid decreasing perfusion of the brain. The posterior tibial artery is located just behind the medial malleolus. It can be palpated by scooping the patient’s heel in your hand and wrapping your fingers around so that the tips come to rest on the appropriate area just below the medial malleolus. The dorsalis pedis artery is located just lateral to the extensor tendon of the big toe and can be identified by asking the patient to flex their toe while you provide resistance to this movement. Gently place the tips of your second, third, and fourth fingers adjacent to the tendon, and try to feel the pulse.
The quality of the pulse is graded on a scale of 0 to 3, with 0 being absent pulses, 1 being decreased pulses, 2 is within normal range, and 3 being increased (also referred to as “bounding”). If unable to palpate a pulse, additional assessment is needed. First, determine if this is a new or chronic finding. Second, if available, use a doppler ultrasound to determine the presence or absence of the pulse. Many agencies use doppler ultrasound to document if a nonpalpable pulse is present. If the pulse is not found, this could be a sign of an emergent condition requiring immediate follow-up and provider notification. See Figures \(\PageIndex{9}\) [19] and \(\PageIndex{10}\) [20] for images of assessing pedal pulses.
Capillary Refill
The capillary refill test is performed on the nail beds to monitor perfusion , the amount of blood flow to tissue. Pressure is applied to a fingernail or toenail until it pales, indicating that the blood has been forced from the tissue under the nail. This paleness is called blanching . Once the tissue has blanched, pressure is removed. Capillary refill time is defined as the time it takes for the color to return after pressure is removed. If there is sufficient blood flow to the area, a pink color should return within 2 to 3 seconds after the pressure is removed. [21]
Edema
Edema occurs when one can visualize visible swelling caused by a buildup of fluid within the tissues. If edema is present on inspection, palpate the area to determine if the edema is pitting or nonpitting. Press on the skin to assess for indentation, ideally over a bony structure, such as the tibia. If no indentation occurs, it is referred to as nonpitting edema. If indentation occurs, it is referred to as pitting edema . See Figure \(\PageIndex{11}\) [22] for images demonstrating pitting edema.
Note the depth of the indention and how long it takes for the skin to rebound back to its original position. The indentation and time required to rebound to the original position are graded on a scale from 1 to 4. Edema rated at 1+ indicates a barely detectable depression with immediate rebound, and 4+ indicates a deep depression with a time lapse of over 20 seconds required to rebound. See Figure \(\PageIndex{12}\) [23] for an illustration of grading edema. Additionally, it is helpful to note edema may be difficult to observe in larger patients. It is also important to monitor for sudden changes in weight, which is considered a probable sign of fluid volume overload.
Heaves or Thrills
You may observe advanced practice nurses and other health care providers palpating the anterior chest wall to detect any abnormal pulsations the underlying cardiac chambers and great vessels may produce. Precordial movements should be evaluated at the apex (mitral area). It is best to examine the precordium with the patient supine because if the patient is turned on the left side, the apical region of the heart is displaced against the lateral chest wall, distorting the chest movements. [24] A heave or lift is a palpable lifting sensation under the sternum and anterior chest wall to the left of the sternum that suggests severe right ventricular hypertrophy. A thrill is a vibration felt on the skin of the precordium or over an area of turbulence, such as an arteriovenous fistula or graft.
Life Span Considerations
The cardiovascular assessment and expected findings should be modified according to common variations across the life span.
Infants and Children
A murmur may be heard in a newborn in the first few days of life until the ductus arteriosus closes.
When assessing the cardiovascular system in children, it is important to assess the apical pulse. Parameters for expected findings vary according to age group. After a child reaches adolescence, a radial pulse may be assessed. Table \(\PageIndex{3}\) outlines the expected apical pulse rate by age.
| Age Group | Heart Rate |
|---|---|
| Preterm | 120-180 |
| Newborn (0 to 1 month) | 100-160 |
| Infant (1 to 12 months) | 80-140 |
| Toddler (1 to 3 years) | 80-130 |
| Preschool (3 to 5 years) | 80-110 |
| School Age (6 to 12 years) | 70-100 |
| Adolescents (13 to 18 years) | 60-90 |
Listen to pediatric heart tones:
Query \(\PageIndex{5}\)
Older Adults
In adults over age 65, irregular heart rhythms and extra sounds are more likely. An “irregularly irregular” rhythm suggests atrial fibrillation , and further investigation is required if this is a new finding. See the hyperlink in the box below for more information about atrial fibrillation.
Listen to atrial fibrillation:
Query \(\PageIndex{6}\)
For more information on atrial fibrillation, visit the following web page: CDC Atrial Fibrillation .
Expected Versus Unexpected Findings
After completing a cardiovascular assessment, it is important for the nurse to use critical thinking to determine if any findings require follow-up. Depending on the urgency of the findings, follow-up can range from calling the health care provider to calling the rapid response team. Table \(\PageIndex{4}\) compares examples of expected findings, meaning those considered within normal limits, to unexpected findings, which require follow-up. Critical conditions are those that should be reported immediately and may require notification of a rapid response team.
| Assessment | Expected Findings | Unexpected Findings (Document and notify the provider if this is a new finding*) |
|---|---|---|
| Inspection | Apical impulse may or may not be visible |
Scars not previously documented that could indicate prior cardiac surgeries
Heave or lift observed in the precordium Chest anatomy malformations |
| Palpation | Apical pulse felt over midclavicular fifth intercostal space |
Apical pulse felt to the left of the midclavicular fifth intercostal space
Additional movements over precordium such as a heave, lift, or thrill |
| Auscultation | S1 and S2 heart sounds in a regular rhythm |
New irregular heart rhythm
Extra heart sounds such as a murmur, S3, or S4 |
| *CRITICAL CONDITIONS to report immediately |
Symptomatic tachycardia at rest (HR>100 bpm)
Symptomatic bradycardia (HR<60 bpm) New systolic blood pressure (<100 mmHg) Orthostatic blood pressure changes (see “Blood Pressure” chapter for more information) New irregular heart rhythm New extra heart sounds such as a murmur, S3, or S4 New abnormal cardiac rhythm changes Reported chest pain, calf pain, or worsening shortness of breath |
See Table \(\PageIndex{5}\) for a comparison of expected versus unexpected findings when assessing the peripheral vascular system.
| Assessment | Expected Findings | Unexpected Findings (Document or notify provider if new finding*) |
|---|---|---|
| Inspection |
Skin color uniform and appropriate for race bilaterally
Equal hair distribution on upper and lower extremities Absence of jugular vein distention (JVD) Absence of edema Sensation and movement of fingers and toes intact |
Cyanosis or pallor, indicating decreased perfusion
Decreased or unequal hair distribution Presence of jugular vein distention (JVD) in an upright position or when head of bed is 30-45 degrees New or worsening edema Rapid and unexplained weight gain Impaired movement or sensation of fingers and toes |
| Palpation |
Skin warm and dry
Pulses present and equal bilaterally Absence of edema Capillary refill less than 2 seconds |
Skin cool, excessively warm, or diaphoretic
Absent, weak/thready, or bounding pulses New irregular pulse New or worsening edema Capillary refill greater than 2 seconds Unilateral warmth, redness, tenderness, or edema, indicating possible deep vein thrombosis (DVT) |
| Auscultation | Carotid pulse | Carotid bruit |
| *CRITICAL CONDITIONS to report immediately |
Cyanosis
Absent pulse (and not heard using Doppler device) Capillary refill time greater than 3 seconds Unilateral redness, warmth, and edema, indicating a possible deep vein thrombosis (DVT) |
Query \(\PageIndex{7}\)
“ Sternum_composition.png ” by Anatomography is licensed under CC BY-SA 2.1 Japan
Query \(\PageIndex{8}\)
“ Sternum_composition.png ” by Anatomography is licensed under CC BY-SA 2.1 Japan
- “Diagram of the human heart” by Wapcaplet is licensed under CC BY-SA 3.0 ↵
- “Diagram of the human heart” by Wapcaplet is licensed under CC BY-SA 3.0 ↵
- “ 2018 Conduction System of Heart.jpg ” by OpenStax is licensed under CC-BY-3.0 . ↵
- “ Arterial System en.svg ” by LadyofHats , Mariana Ruiz Villarreal is in the Public Domain ↵
- “ Venous system en.svg ” by Lady of Hats Mariana Ruiz Vilarreal is in the Public Domain ↵
- This work is a derivative of Clinical Procedures for Safer Patient Care by British Columbia Institute of Technology licensed under CC BY 4.0 ↵
- Felner, J. M. (1990). An overview of the cardiovascular system. In Walker, H. K., Hall, W. D., & Hurst, J. W. (Eds.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., Chapter 7). Butterworths. www.ncbi.nlm.nih.gov/books/NBK393/↵
- Scott, C. & MacInnes, J. D. (2013, September 27). Cardiac patient assessment: putting the patient first. British Journal of Nursing, 15 (9). doi.org/10.12968/bjon.2<IP_ADDRESS>91↵
- Scott, C. & MacInnes, J. D. (2013, September 27). Cardiac patient assessment: putting the patient first. British Journal of Nursing, 15 (9). doi.org/10.12968/bjon.2<IP_ADDRESS>91↵
- Felner, J. M. (1990). An overview of the cardiovascular system. In Walker, H. K., Hall, W. D., & Hurst, J. W. (Eds.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., Chapter 7). Butterworths. www.ncbi.nlm.nih.gov/books/NBK393/↵
- This work is a derivative of Clinical Procedures for Safer Patient Care by British Columbia Institute of Technology licensed under CC BY 4.0 ↵
- “ Swollen feet at Harefield Hospital edema.jpg” by Ryaninuk is licensed under CC BY-SA 4.0 ↵
- Simon, E. C. (2014). Leg edema assessment and management. MEDSURG Nursing, 23(1), 44-53. ↵
- This work is a derivative of Clinical Procedures for Safer Patient Care by British Columbia Institute of Technology licensed under CC BY 4.0 ↵
- This work is a derivative of Clinical Procedures for Safer Patient Care by British Columbia Institute of Technology licensed under CC BY 4.0 ↵
- “ Deep vein thrombosis of the right leg.jpg ” by James Heilman, MD is licensed under CC BY-SA 3.0 ↵
- “Cardiac Auscultation Areas” by Meredith Pomietlo for Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- Felner, J. M. (1990). An overview of the cardiovascular system. In Walker, H. K., Hall, W. D., & Hurst, J. W. (Eds.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., Chapter 7). Butterworths. www.ncbi.nlm.nih.gov/books/NBK393/↵
- “DSC_2277.jpg” by British Columbia Institute of Technology is licensed under CC BY 4.0 . Access for free at https://opentextbc.ca/clinicalskills/chapter/2-5-focussed-respiratory-assessment/ ↵
- “DSC_2314.jpg” by British Columbia Institute of Technology is licensed under CC BY 4.0. Access for free at https://opentextbc.ca/clinicalskills/chapter/2-5-focussed-respiratory-assessment/ ↵
- A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M., Inc.; c1997-2020. Capillary nail refill test; [updated 2020, Aug 9] https://medlineplus.gov/ency/article/003247.htm ↵
- “ Combinpedal.jpg ” by James Heilman, MD is licensed under CC BY-SA 3.0 ↵
- “Grading of Edema” by Meredith Pomietlo for Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- Felner, J. M. (1990). An overview of the cardiovascular system. In Walker, H. K., Hall, W. D., & Hurst, J. W. (Eds.), Clinical methods: The history, physical, and laboratory examinations (3rd ed., Chapter 7). Butterworths. www.ncbi.nlm.nih.gov/books/NBK393/↵ | 5,851 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Nursing/Nursing_Skills_(OpenRN)/09%3A_Cardiovascular_Assessment/9.03%3A_Cardiovascular_Assessment | libretexts | libretexts-0000.json.gz:8157 | https://med.libretexts.org/Bookshelves/Nursing/Nursing_Skills_(OpenRN)/09%3A_Cardiovascular_Assessment/9.03%3A_Cardiovascular_Assessment |
BEfhja3AyfIWFaI_ | 1.9: Soul Music | 1.9: Soul Music
Soul Music
Soul music has its roots most firmly implanted in gospel music, both in lyrical content (messages of love and relationships, though not necessarily spiritual) and especially in the emotional and embellished vocal style. Like Gospel, Soul vocal styles incorporate many notes per syllable in an embellished and improvisational approach. The lyrical content, with roots in Gospel, was intertwined with the civil rights movement, singing of equality, love, and respect for your fellow human being.
The soul styles of the northern and southern USA had differing qualities. Southern styles often had a gritty and energetic vocal quality, and the instrumental playing was usually intense and energetic. Northern styles would usually had a more refined sound with improvisation and embellishments less pronounced. One possible reason for this is that gospel singing varied from church to church and region to region, developing in isolation without the aid/influence of radio.
Atlantic Records
Atlantic Records was formed in 1947 and was largely responsible for the success of soul artists like Ray Charles, Otis Redding, Aretha Franklin, and others. Later on, Atlantic would distribute recordings from a very diverse group of artists. But early on they were best known as a primary distributor of soul music. Atlantic’s recording studio was in New York but they would move artists to different studios (such as Stax studios in Memphis using Booker T and the MGs) depending on what kind of soul music they wanted to produce.
Ray Charles
Ray Charles – (1930–2004) Blind since the age of 6, Ray Charles nevertheless learned piano, trumpet, saxophone, and clarinet. He also learned to read and write music in braille as well as studying composition. Charles never actually sang gospel in church, but incorporated it into his rhythm and blues music. He was unique in his ability to synthesize country, jazz, rhythm and blues, blues, and gospel, sometimes using the story line lyrics of country and even recording albums of country covers.
Charles spent a few years starting in the late 1940s performing around the country with his group the McSon Trio. The group made their first recordings in 1948-49. Charles was eventually signed to Swingtime Records, and later Atlantic Records where he had his first great commercial success. Songs like “I’ve Got a Woman” (1954) provided Charles with radio play and wide exposure, and he quickly became one of the best known names in Soul. By 1959, Charles’ reached a new commercial high point with the single, “What’d I Say?” which became a top 10 hit on the pop charts. “I’ve Got a Woman” and “What’d I Say?” are examined in more detail below in Listening Examples 9.1.
In 1962, Charles released his groundbreaking album Modern Sounds in Country and Western Music where he integrated the sounds of soul and blues with country and folk music in a revolutionary way. He blends the song forms and melodies of country and folk with stylistic norms from soul such as embellished vocal melodies and uneven beat subdivisions from blues.
Otis Redding
Otis Redding (1941–1967) was the biggest selling singer at Stax records whose emotional vocal style was a mixture of the rock aggressiveness of Little Richards and the smoother gospel style of Sam Cooke. He was also a hit songwriter, writing many of his own songs including “Respect”, the song that became best known in the version recorded by Aretha Franklin. Redding used gospel techniques like melismas that built tension, and put on energetic live performances as evidenced by the album Live in Europe from 1967 which includes a high-energy version of his hit “Can’t Turn You Loose” (1965) and an intense, soul-infused cover version of “Satisfaction” by The Rolling Stones. He died in a plane crash in 1967, only 3 days after recording what would become his biggest hit, “(Sittin’ on) The Dock of the Bay”, co-written with Steve Cropper. More on that song in Listening Examples 9.1 below.
Aretha Franklin
Aretha Franklin (1942–2018) was one of the most influential and well known soul singers in American popular music. The daughter of a minister, Franklin spent her youth singing gospel music in her father’s church. In her teens she began traveling to other churches and concert halls, performing and meeting gospel singers like Mahalia Jackson, Sam Cooke, and others.
She moved to New York at age 18 to sing secular music like the blues. She was encouraged by producers to tone down the gospel influence for a more restrained approach. This changed in 1966 when Franklin was signed to Atlantic records and was encouraged to put that energy and emotion back into her music. At Atlantic Franklin had many hits including “Respect” (1967) which was No. 1 on both the pop and Rhythm and Blues charts.
“Respect” (Found in Listening Examples 9.1 ) was written by Otis Redding, but Franklin’s version became even more popular than Redding’s. The lyrics gained new meaning when sung from a female perspective. Initially a song about a troubled relationship between two people, Franklin’s version of “Respect” became an anthem for gender equality at a time when the discrepancy between males and females was heavily in the advantage of the male. The use of the horn section is apparent, and the vocal style of Franklin is reminiscent of the style of gospel singers like Mahalia Jackson and the blues styles of Bessie Smith and Ma Rainey. The form is comprised of an instrumental opening, three vocal sections (A section), an instrumental section (B), another A section, the C section ( the R-E-S-P-E-C-T breakdown), followed by a fragment of another A section.
Listening Examples 9.1
Ray Charles: “Confession Blues” (1949) is Ray Charles’ first recording and features the McSon Trio. Listen to the lyrics and try to identify the form. Stylistically, what does this song closely resemble?
Ray Charles: “I’ve Got A Woman” (1954) was an early hit song by Ray Charles. Lyrically, it is a reflection of attitudes on gender roles in the 1950s with lines like “ She’s there to love me, Both day and night. Never grumbles or fusses, Always treats me right. Never runnin’ in the streets, Leavin’ me alone. She knows a woman’s place, Is right there, now, in her home “. Lyrics here: I Got a Woman Lyrics It presents the listener with an interesting hybrid form, blending elements of 12-bar blues form with and overall AABA structure. The A sections use elements of the AAB lyrical scheme, but bring back the A line one more time after the B line, such as the following from the first A section:
A – Well, I got a woman, way over town, That’s good to me, oh yeah
A – Said I got a woman, way over town, Good to me, oh yeah
B – She gives me money when I’m in need, Yeah, she’s a kind of friend indeed
A – I got a woman, way over town, That’s good to me, oh yeah
Ray Charles: “What’d I Say?” (1959) was a No. 1 hit on the rhythm and blues charts and No. 6 on the pop charts. The single release included two separate versions on each side. Side A was a standard rhythm and blues version with Charles accompanied by a band, while side B features a soul version with call and response between Charles and a gospel-style vocal group as well as Jazz styled nonsense syllables. Formally, it is a 12-bar blues that incorporates “stop-time” where the bass and drums will cut out and let the electric piano play solo for a brief period.
“Careless Love” is a traditional country/folk song reinterpreted by Charles with gospel-style vocals and a horn section, taken at a slow tempo reminiscent of brooding blues songs by performers like B.B. King. It was released on Charles’ album “Modern Sounds in Country and Western Music” (1962).
Otis Redding: “Sittin’ on the Dock of the Bay” by Otis Redding. I play the chords to an entire section of “Sittin’ on the Dock of the Bay” (including the short intro). Notice how many chords are being played as opposed to a form like 12-bar blues. There are five different chords being played multiple times (compared to 3 in 12 bar blues form) and the entire section is 16 bars long.
Aretha Franklin:
Sam Cooke
Sam Cooke – (1935–1964) was the son of a Baptist minister, surrounded by gospel music as a child. He began working as a professional singer in 1951 taking the lead vocal duties in the gospel group, the Soul Stirrers. In 1956 he left the Soul Stirrers and branched out into secular music, releasing “You Send Me” in 1957, launching a pop music career in which he would blossom into a hit songwriter. When listening to “You Send Me” in Listening Examples 9.2 below, notice how Cooke embellishes certain syllables with many notes in an improvisation style. Formally, there are two contrasting sections that make up the entire piece; the A section (“You Send Me…”etc), two B sections (“At first I thought it was infatuation…”) incorporated in between, and it it is laid out as follows: AABAAABA. Cooke takes some gospel influenced improvisational liberties during the 4th and 5th iterations of the A section.
Cooke’s recorded output was often smooth and pop-friendly. Songs such as “Cupid”, “Chain Gang”, and “Twistin’ the Night Away” were generally toned-down, and the gospel vocal embellishments are rare (“You Send Me” is an exception to this generalization). By contrast, the 1963 live recording Live at the Harlem Square Club showcased a looser, more raw Sam Cooke; high energy, heavily embellished vocal melodies, and an almost scream-like vocal timbre. Cooke was tragically shot and killed under mysterious circumstances in 1964.
James Brown
James Brown – (1933–2006) Began performing as a child dancing on the streets for tips to save money for his aunt who was left to raise him after his parents left. Brown learned to sing gospel in a local church, and joined a gospel group in his twenties, becoming the lead singer. A change to secular music brought a name change to the Famous Flames.
Brown had his first hit with “Please Please Please” (1956) as the leader of the Famous Flames. The music featured a triplet pattern in the piano common in gospel and doo wop (dividing the beat into 3 parts instead of 2 parts) and doo wop-style backing-vocals (featuring nonsense syllables and echoes of the lyrics).
The stage act developed by Brown became legendary, with dramatic and intense vocal embellishments and complex dancing including dance steps, the splits, and drops to his knees. His vocal sound had a large expressive range: it could be soft and tender, or aggressive and growly like Little Richard. He also gave vocal cues to his band; each time he gave a certain “call”, horns or backing vocals would respond with a riff or short vocal phrase.
By the 70’s his music developed to include high energy funk alongside his earlier rhythm and blues. Brown developed drug problems (he had long been anti-drug), and these drug problems resulted in domestic violence charges and other legal troubles in the late 80’s that landed him in prison for two years. Nevertheless, he was popular with fans of rhythm and blues and funk his entire career.
Stax and Volt Records
Stax records (and its subsidiary, Volt) became the starting point for many soul artists’ careers. Based in Memphis Tennessee, this company attracted performers of Memphis Soul, a brand of soul music that combined the energy of Little Richard with gospel based singers like James Brown. The records that came out of Stax were often consistent because the studio group, Booker T and the MGs, played on many of the records. The group was named after their organist/arranger Booker T. Jones. They were also creatively involved in the songwriting and arranging process. In particular, guitarist Steve Cropper was a songwriter that co-wrote many hit songs at Stax with artists like Otis Redding and Wilson Pickett.
Wilson Pickett (1941-2006) Singer who began working at Stax, co-wrote “In the Midnight Hour” with Steve Cropper, became a No. 1 hit on the Rhythm and Blues charts in 1965. Cropper was an important songwriter for Stax. “In the Midnight Hour” used a parallel movement where multiple horns playing lines that move higher or lower in tandem, that became a signature sound of Memphis soul known as the “Memphis Horn Sound”.
Exercise 1
The first part of the article linked provides a short background into Berry Gordy and Motown. Later it contains a detailed analysis of some of the rhythmic characteristics of the Soul music from Motown and how these rhythms led to funk music. This analysis is, in part, a response to critics who were disapproving of the repetitive nature of popular music styles that didn’t fully comprehend it’s subtlety and nuance. Please read pgs. 1-5 (short bio of Gordy and Motown) and “Theorizing the Groove”, pgs. 14-20.
Listening Examples 9.2
Sam Cooke:
- “You Send Me” A section played by Todd Smith
- “You Send Me” B section played by Todd Smith
- “You Send Me” original recording by Sam Cooke
James Brown:
- “Please Please Please” live from the TAMI show in 1964. Notice the theatrical style of Brown as he performs the famous “cape routine”. The routine goes as follows: He performs in such a passionate way that he collapses from exhaustion and is assisted offstage by a bandmate, but as he’s being led off he has a change of heart. He throws the cape off his back and hobbles back to the microphone to finish the song. He repeats this a number of times, and the audience goes wild each time! Formally, the song uses a relatively new (for us) song form: Repeated A sections. This form allows for James Brown to improvise musically and theatrically over top of the form as it simply cycles the same music over and over.
Wilson Pickett:
Motown Records
Motown was a record company that created a specific brand of soul music (known aptly as “Motown”) that sought to gain the respect of white audiences for African Americans, not simply acceptance of the music. Motown represents the northern variety of soul music with it’s emphasis on refined imagery and arrangements.
Founded by songwriter Berry Gordy Jr. (born 1929) who named Motown after Detroit which is known as the Motor City. Motown artists sang of love and other subjects that a broad spectrum of humanity could identify with. With Motown one can see many No. 1 hits in both the Pop and R&B charts.
Gordy emphasized a sophisticated, refined image for his performers. Performers were molded through training in ‘sophisticated’ ways of walking, speaking and dancing. Musically, producers at Motown used refined background arrangements including orchestral strings, jazz bands, and other instruments. Compared to the singers at Stax records, Motown singers sang in a polished and conservative style. Blue notes and improvisational gospel-style singing were rarely used, and the music was often aimed specifically at a white audience. To draw listeners in, Motown producers often used catchy, repetitive rhythms and bass lines. Gordy, for the most part, had complete control over the artists working at Motown, and very few were in control of their own work.
The Funk Brothers
The regular studio group for Motown records was the Funk Brothers. This group was unique in that they had a background in jazz and rhythm and blues and had highly developed instrumental skills. Like Stax records with Booker T and the MGs, Motown recordings with the Funk Brothers feature more active contributions from the studio band than most other studio groups, many of whom were there simply to provide straightforward background music for the singers.
The Funk Brothers used three guitarists, each with their own role and style. Robert White played full chords on the beats with a warm tone, Eddie Willis played blues-styled melodic fills, and Joe Messina would stress the backbeat (beats 2 & 4) with bright percussive chords. Bassist James Jamerson played walking bass lines on his electric bass guitar with chromatic notes and syncopated rhythms instead of the usual overly simplified bass patterns. Earl Van Dyke was the leader and keyboardist, often playing a grand piano. Organ, horns, vibraphone, and other percussion instruments were often incorporated into the texture.
Smokey Robinson
Smokey Robinson – (Born 1940) Singer and highly successful songwriter. Robinson and his group, The Miracles, were one of the first groups signed to Motown by Gordy who was most impressed with Robinson’s songwriting abilities. Robinson wrote songs for Marvin Gaye, the Temptations, and other groups at Motown. In addition to his song-writing duties he produced many of Motown’s recordings and eventually became the vice-president of Motown.
The Temptations
The Temptations were an all male group, and were one of the most popular on the Motown label. Smokey Robinson was their primary songwriter for their early hits. He also produced many of their recordings including “My Girl” (1965) which Robinson co-wrote, becoming one of their biggest hits. It used a polished and lush background with a variety of instruments including orchestral brass and strings, similar to a Phil Spector recording. It reached No. 1 on both the Pop and Rhythm and Blues charts.
The Temptations’ sound changed over the years, and as the lineup was constantly changing, so was the lead vocalist. Up to 1965, the lead vocalist was a tenor (higher-range male singer) named Eddie Kendricks, but starting with “My Girl” it became baritone (lower-range male singer) David Ruffin. In the later 1960’s Ruffin left the group and Norman Whitfield became their producer. With Whitfield, their sound evolved into the funk stylings of James Brown and Sly and the Family Stone.
The Supremes
The Supremes were one of the most popular girl groups at Motown, led by lead singer Diana Ross. Their refined sound and image was characteristic of Motown groups, and they were highly successful, appealing to more mature audiences. Most of their hits were written by the song-writing team of Holland-Dozier-Holland. The songs from this team often featured a “hook” (a simple and very catchy melody) over and over again. The form of these songs often followed a format of “Repeated A Sections” that would reenforce these melodic hooks. Put simply, a section of music is repeated over and over, while the lyrics would change
Stevie Wonder
Stevie Wonder – (Born 1950) Began his career as a child. At age 13, he already had his first hit song (Motown’s second hit) “Fingertips (Part II)” in 1963. It reached No. 1 in both the Rhythm and Blues and Pop charts. Born blind and singing with a gospel-styled voice, he became known as a child prodigy and a young Ray Charles. Wonder learned many instruments as a child including harmonica, percussion, and piano.
When he turned 21, Wonder renegotiated his contract with Motown and gained complete control over his recordings, something that most Motown artists would never have. This period marked a significant change in his music that saw him embrace funk, gospel, and jazz, as well as Latin and African rhythms.
The “classic period” of Wonder’s music began with Music of My Mind (1972) and culminated with Songs in the Key of Life (1976). This period saw Wonder embrace new music technology such as synthesizers.
Jackson 5
When Stevie Wonder grew out of the child star image, Berry Gordy Jr. began looking for another similar performer. He found what he was looking for in Michael Jackson (1958-2009) and his brothers. The group became the Jackson Five. Gordy and Motown writers created songs that fit the youthful image and would attract the attention of teens and preteens. These young fans became the Jackson 5’s primary audience.
The Jackson’s father had been their manager and remained so when they signed to Motown. However, he was denied complete control the way Stevie Wonder had and so he moved the group to a different label. Later on, Michael Jackson had an enormously successful solo career after leaving the group.
Listening Examples 9.3
Smokey Robinson and the Miracles : In “You Really Got a Hold on Me” the triplet-pattern (three accents per beat) in the piano and the drums are very common in Soul music and pop music in general around this time. Notice the use of “stop time”, reminiscent of early rock and roll, during the section where Robinson sings “Hold Me! Hold Me! Hold Me!” etc. Also, the song features the relatively new form (see ch. 8) called verse-chorus form.
The Supremes: “Where Did Our Love Go?” became The Supremes’ first No. 1 hit on the pop charts. The music resonated with Americans struggling to understand the JFK assassination, the Cold War, and the emerging Vietnam War. Formally, the songs is simple; 16-bar A sections repeated over and over until the song fades out, also known as Repeated A sections . The chord sequence consists of 5 chords that continuously repeat over each A section throughout the song. The “hook” featured in this song is the vocal melody that continually repeats over every A section throughout the entire song (with the exception of a brief baritone saxophone solo).
The Temptations: “My Girl” Uses a new song form. Look at the lyrics here: My Girl – Lyrics What form is it?
Stevie Wonder: A young Stevie Wonder plays “Fingertips” showcasing his skill as a performer and harmonica player. “Sir Duke” uses complex chord changes from jazz, long complex gospel/soul/blues style melodies influenced by in part by African music, horn sections, electric instruments, and funk grooves inspired by artists like James Brown. The “Duke” would be Duke Ellington, and the song is a celebration of music history and the important figures that have contributed to a positive evolution of music. Finally listen to “Signed, Sealed, Delivered” live (1973).
Jackson 5: “I Want You Back” was the debut and first hit by the Jackson Five, reaching No. 1 on the pop charts. | 4,754 | common-pile/libretexts_filtered | https://human.libretexts.org/Courses/Western_Washington_University/Popular_Music_(Smith)/01%3A_Readings/1.09%3A_Soul_Music | libretexts | libretexts-0000.json.gz:21660 | https://human.libretexts.org/Courses/Western_Washington_University/Popular_Music_(Smith)/01%3A_Readings/1.09%3A_Soul_Music |
IwvIXKKEBlc39Eq- | 10.7: In Re Bonner – 151 US 242 (1894) | 10.7: In Re Bonner – 151 US 242 (1894)
U.S. Supreme Court
In re Bonner, 151 U.S. 242 (1894)
In re Bonner
No. 8, Original
Argued November 27-28, 1893
Decided January 15, 1894
151 U.S. 242
ORIGINAL
Syllabus
When a person accused of crime is convicted in a court of the United States and is sentenced by the court, under Rev.Stat. § 5356, to imprisonment for one year and the payment of a fine, the court is without jurisdiction to further adjudge that that imprisonment shall take place in a state penitentiary under Rev.Stat. § 5546, and the prisoner, if sentenced to be confined in a state penitentiary, is entitled to a writ of habeas corpus directing his discharge from the custody of the warden of the state penitentiary, but without prejudice to the right of the United States to take any lawful measures to have the petitioner sentenced in accordance with law upon the verdict against him.
Where a conviction is correct, and where the error or excess of jurisdiction is the ordering the prisoner to be confined in a penitentiary where the law does not allow the court to send him, there is no good reason why jurisdiction of the prisoner should not he reassumed by the court that imposed the sentence in order that its defect may be corrected.
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The court discharging the prisoner in such case on habeas corpus should delay his discharge for such reasonable time as may be necessary to have him taken before the court where the judgment was rendered, in order that the defects in the former judgment for want of jurisdiction, which are the subjects of complaint, may be corrected.
The petitioner, John Bonner, a citizen of the United States, represents that he is now and has been since the 23d of May, 1893, unlawfully deprived of his liberty by one P. W. Madden, as warden of the penitentiary of Iowa situated in Anamosa, in that state. He sets forth as the cause of his restrain and detention that at the October term, 1892, of the United States Court for the Third Judicial Division of the Indian Territory, he was indicted for the larceny, in May previous, in the Chickasaw Nation, within the Indian Territory, of four head of cattle, of the value of fifty dollars, the property of one Robert Williams, who was not a member of any Indian tribe; that during that month, he was arraigned before the same court and pleaded not guilty to the indictment, and was tried and found guilty. The statute under which the indictment was found is contained in section 5356 of the Revised Statutes, and is as follows:
“Every person who, upon the high seas, or in any place under the exclusive jurisdiction of the United States, takes and carries away, with intent to steal or purloin, the personal goods of another shall be punished by a fine of not more than one thousand dollars, or by imprisonment not more than one year, or by both such fine and imprisonment.”
The court, by its judgment, sentenced the petitioner to imprisonment in the penitentiary at Anamosa, in the State of Iowa, for the term of one year, and to the payment of a fine of $1,000. It also added that the marshal of the court, to whose custody he was then committed, should safely keep and convey the petitioner, and deliver him to the custody of the warden of the penitentiary, who would receive and keep him in prison for the period of one year in execution of the sentence. The petitioner also sets forth that the warden of the penitentiary has no other authority to hold him than the said judgment and order of commitment.
The petitioner alleges that the said sentence and order of commitment are void; that the court was without power or jurisdiction under the law to render the judgment, and that he had applied to the United States judge of the Northern District of Iowa for a writ of habeas corpus to be released from confinement, and that the writ was denied to him. He
Home Page 151 U. S. 244
therefore prays that this Court will issue the writ of habeas corpus to the said warden to appear before this Court and show what authority, if any, he has for restraining the petitioner of his liberty, and that upon final hearing he may be discharged.
An order was issued from this Court in October last to the warden to show cause why the writ should not be granted as prayed. The warden returns answer that he holds the prisoner by virtue of a warrant of commitment issued upon the judgment and sentence of the United States court as above stated, of which a copy is annexed to the petition, and that at the time of the petitioner’s conviction and of the judgment and sentence, there was no penitentiary or jail suitable for the confinement of convicts, or available therefor, in the Indian Territory, and that the state penitentiary at Anamosa had been duly designated by the Attorney General, under section 5546 of the Revised Statutes of the United States, as the place of confinement for prisoners convicted of crime by that court, and that the order of the court for the confinement of the petitioner in that penitentiary under its sentence of imprisonment was in pursuance of that designation.
So much of section 5546 of the Revised Statutes as bears upon the question under consideration in this case is as follows:
“All persons who have been or who may hereafter be convicted of crime by any court of the United States whose punishment is imprisonment in a district or territory where, at the time of conviction, there may be no penitentiary or jail suitable for the confinement of convicts or available therefor shall be confined during the term for which they have been or may be sentenced in some suitable jail or penitentiary in a convenient state or territory, to be designated by the Attorney General, and shall be transported and delivered to the warden or keeper of such jail or penitentiary by the marshal of the district or territory where the conviction has occurred. ”
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MR. JUSTICE FIELD, after stating the facts in the foregoing language, delivered the opinion of the Court.
The petitioner asks for the issue of the writ of habeas corpus in order that he may be thereby set at liberty, on the ground that his imprisonment in the penitentiary at Anamosa, in Iowa, is in pursuance of a judgment of a court which possessed no authority under the law to pass sentence upon him of imprisonment in the state penitentiary, upon his conviction of the offense for which he was indicted and tried. That is a sentence which can only be imposed where it is specifically prescribed, or where the imprisonment ordered is for a period longer than one year, or at hard labor. To an imprisonment for that period or at hard labor in a state penitentiary infamy is attached, and a taint of that character can be cast only in the cases mentioned.
Section 5356 of the Revised Statutes of the United States, under which the defendant was indicted and convicted, prescribes as a punishment for the offenses designated fine or imprisonment — the fine not to exceed $1,000, and the imprisonment not more than one year — or by both such fine and imprisonment. Such imprisonment cannot be enforced in a state penitentiary. Its limitation, being to one year, must be enforced elsewhere. Section 5541 of the Revised Statutes provides that:
“In every case where any person convicted of any offense against the United States is sentenced to imprisonment for a period longer than one year, the court by which the sentence is passed may order the same to be executed in any state jail or penitentiary within the district or state where such court is held, the use of which jail or penitentiary is allowed by the legislature of the state for that purpose.”
And section 5542 provides for a similar imprisonment in a state jail or penitentiary where the person has been convicted of any offense against the United States and sentenced to imprisonment and confinement at hard labor. It follows
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that the court had no jurisdiction to order an imprisonment when the place is not specified in the law, to be executed in a penitentiary, when the imprisonment is not ordered for a period longer than one year or at hard labor. The statute is equivalent to a direct denial of any authority on the part of the court to direct that imprisonment be executed in a penitentiary in any cases other than those specified. Whatever discretion, therefore, the court may possess in prescribing the extent of imprisonment as a punishment for the offense committed, it cannot, in specifying the place of imprisonment, name one of these institutions. This has been expressly adjudged in In re Mills, 135 U. S. 263 , 135 U. S. 270 , which in one part of it presents features in all respects similar to those of the present case.
There, the petitioner, Mills, was detained by the warden of the state penitentiary in Columbus, Ohio, pursuant to two judgments of the District Court of the United States for the Western District of Arkansas sentencing him in each case to confinement in the penitentiary of that state. Application was made by the prisoner for a writ of habeas corpus on the ground that the court by which he was tried had no jurisdiction of the offenses with which he was charged, and on the further ground that his detention in the penitentiary under the sentences, neither of which was for a longer period than one year, was contrary to the laws of the United States. The first position was not considered tenable, but the second was deemed sufficient to authorize the issue of the writ. The Court held that, apart from any question as to whether the court below had jurisdiction to try the offense charged, the detention of the petitioner in the penitentiary upon sentences neither of which was for imprisonment longer than one year was in violation of the laws of the United States, and that he was therefore entitled to be discharged from the custody of the warden of the institution. “A sentence simply of imprisonment,'” said the Court,
“in the case of a person convicted of an offense against the United States where the statute prescribing the punishment does not require that the accused shall be confined in a penitentiary cannot be executed by confinement in that institution except in cases where
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the sentence is ‘for a period longer than one year.’ There is consequently no escape from the conclusion that the judgment of the court sentencing the petitioner to imprisonment in a penitentiary in one case for a year and in the other for six months was in violation of the statutes of the United States. The court below was without jurisdiction to pass any such sentences, and the orders directing the sentences of imprisonment to be executed in a penitentiary are void.”
The Court added: “This is not a case of mere error, but one in which the court below transcended its power,” citing Ex Parte Lange, 18 Wall. 163, 85 U. S. 176 ; Ex Parte Parks, 93 U. S. 18 , 93 U. S. 23 ; Ex Parte Virginia, 100 U. S. 339 , 100 U. S. 343 ; Ex Parte Rowland, 104 U. S. 604 , 104 U. S. 612 ; In re Coy, 127 U. S. 731 , 127 U. S. 738 , and Hans Nielson, Petitioner, 131 U. S. 176 , 131 U. S. 182 .
Counsel for the government admits that upon the authority of that case, construing the Revised Statutes, the petitioner should not have been sentenced to imprisonment in the penitentiary, but he claims that the judgment and sentence are not for that cause void, so as to entitle the petitioner to a writ of habeas corpus for his discharge, and he asks the Court to reconsider the doctrine announced, contending that neither the reason of the law nor the authorities sustain the position. According to his argument, it would seem that the court does not exceed its jurisdiction when it directs imprisonment in a penitentiary, to which place it is expressly forbidden to order it. It would be as well, and be equally within its authority, for the court to order the imprisonment to be in the guard house of a fort, or the hulks of a prison ship, or in any other place not specified in the law.
We are unable to agree with the learned counsel, but are of opinion that in all cases where life or liberty is affected by its proceedings, the court must keep strictly within the limits of the law authorizing it to take jurisdiction, and to try the case, and to render judgment. It cannot pass beyond those limits in any essential requirement in either stage of these proceedings, and its authority in those particulars is not to be enlarged by any mere inferences from the law or doubtful construction of its terms. There has been a great deal said
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and written, in many cases with embarrassing looseness of expression, as to the jurisdiction of the courts in criminal cases. From a somewhat extended examination of the authorities, we will venture to state some rule applicable to all of them, by which the jurisdiction as to any particular judgment of the court in such cases may be determined. It is plain that such court has jurisdiction to render a particular judgment only when the offense charged is within the class of offenses placed by the law under its jurisdiction, and when, in taking custody of the accused and in its modes of procedure to the determination of the question of his guilt or innocence, and in rendering judgment, the court keeps within the limitations prescribed by the law, customary or statutory. When the court goes out of these limitations, its action, to the extent of such excess, is void. Proceeding within these limitations, its action may be erroneous, but not void.
To illustrate: in order that a court may take jurisdiction of a criminal case, the law must in the first instance authorize it to act upon a particular class of offenses within which the one presented is embraced. Then comes the mode of the presentation of the offense to the court. That is specifically prescribed. If the offense be a felony, the accusation in the federal court must be made by a grand jury summoned to investigate the charge of the public prosecutor against the accused. Such indictment can only be found by a specified number of the grand jury. If not found by that number, the court cannot proceed at all. If the offense be only a misdemeanor, not punishable by imprisonment in the penitentiary, Mackin v. United States, 117 U. S. 348 , the accusation may be made by indictment of the grand jury, or by information of the public prosecutor. An information is a formal charge against the accused of the offense, with such particulars as to time, place, and attendant circumstances as will apprise him of the nature of the charge he is to meet, signed by the public prosecutor. When the indictment is found, or the information is filed, a warrant is issued for the arrest of the accused, to be brought before the court, unless he is at the time in custody, in which case an order for that purpose is made, to the end in
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either case that he may be arraigned and plead to the indictment or information. When he is brought before the court, objections to the validity or form of the indictment or information, if made, are considered, or issue is joined upon the accusation. When issue is thus joined, the court must proceed to trial by a jury, except in case of the accused’s confession. It cannot then proceed to determine the issue in any other way. When the jury have rendered their verdict, the court has to pronounce the proper judgment upon such verdict, and the law, in prescribing the punishment either as to the extent or the mode or the place of it, should be followed. If the court is authorized to impose imprisonment, and it exceeds the time prescribed by law, the judgment is void for the excess. If the law prescribes a place of imprisonment, the court cannot direct a different place not authorized. It cannot direct imprisonment in a penitentiary when the law assigns that institution for imprisonment under judgments of a different character. If the case be a capital one and the punishment be death, it must be inflicted in the form prescribed by law. Although life is to be extinguished, it cannot be by any other mode. The proposition put forward by counsel that if the court has authority to inflict the punishment prescribed, its action is not void though it pursues any form or mode which may commend itself to its discretion, is certainly not to be tolerated. Imprisonment might be accompanied with inconceivable misery and mental suffering by its solitary character or other attending circumstances. Death might be inflicted by torture or by starvation, or by drawing and quartering. All these modes, or any of them, would be permissible if the doctrine asserted by him can be maintained.
A question of some difficulty arises which has been disposed of in different ways, and that is as to the validity of a judgment which exceeds in its extent the duration of time prescribed by law. With many courts and judges, perhaps with the majority, such judgment is considered valid to the extent to which the law allowed it to be entered, and only void for the excess. Following out this argument, it is further claimed that therefore the writ of habeas corpus cannot be
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invoked for the relief of a party until the time has expired to which the judgment should have been limited. But that question is only of speculative interest here, for there is here no question of excess of punishment. The prisoner is ordered to be confined in the penitentiary, where the law does not allow the court to send him for a single hour. To deny the writ of habeas corpus in such a case is a virtual suspension of it, and it should be constantly borne in mind that the writ was intended as a protection of the citizen from encroachment upon his liberty from any source — equally as well from the unauthorized acts of courts and judges as the unauthorized acts of individuals.
The law of our country takes care, or should take care, that not the weight of a judge’s finger shall fall upon any one except as specifically authorized. A rigid adherence to this doctrine will give far greater security and safety to the citizen than permitting the exercise of an unlimited discretion on the part of the courts in the imposition of punishments, as to their extent, or as to the mode or place of their execution, leaving the injured party, in case of error, to the slow remedy of an appeal from the erroneous judgment or order, which in most cases would be unavailing to give relief In the case before us, had an appeal been taken from the judgment of the United States Court of the Indian Territory, it would hardly have reached a determination before the period of the sentence would have expired and the wrong caused by the imprisonment in the penitentiary have been inflicted.
Much complaint is made that persons are often discharged from arrest and imprisonment when their conviction, upon which such imprisonment was ordered, is perfectly correct, the excess of jurisdiction on the part of the court being in enlarging the punishment, or in enforcing it in a different mode or place than that provided by the law. But in such cases, there need not be any failure of justice, for where the conviction is correct and the error or excess of jurisdiction has been as stated, there does not seem to be any good reason why jurisdiction of the prisoner should not be reassumed by the court that imposed the sentence in order that its defect may be corrected.
Home Page 151 U. S. 260
The judges of all courts of record are magistrates, and their object should be not to turn loose upon society persons who have been justly convicted of criminal offenses, but, where the punishment imposed, in the mode, extent, or place of its execution, has exceeded the law, to have it corrected by calling the attention of the court to such excess. We do not perceive any departure from principle, or any denial of the petitioner’s right, in adopting such a course. He complains of the unlawfulness of his place of imprisonment. He is only entitled to relief from that unlawful feature, and that he would obtain if opportunity be given to that court for correction in that particular. It is true, where there are also errors on the trial of the case affecting the judgment not trenching upon its jurisdiction, the mere remanding the prisoner to the original court that imposed the sentence to correct the judgment in those particulars for which the writ is issued would not answer, for his relief would only come upon a new trial, and his remedy for such errors must be sought by appeal or writ of error. But in a vast majority of cases, the extent and mode and place of punishment may be corrected by the original court without a new trial, and the party punished as he should be, while relieved from any excess committed by the court, of which he complains. In such case, the original court would only set aside what it had no authority to do, and substitute directions required by the law to be done upon the conviction of the offender.
Some of the state courts have expressed themselves strongly in favor of the adoption of this course, where the defects complained of consist only in the judgment — in its extent or mode, or place of punishment — the conviction being in all respects regular. In Beale v. Commonwealth, 25 Penn.St. 11, 22, the Supreme Court of Pennsylvania said:
“The common law embodies in itself sufficient reason and common sense to reject the monstrous doctrine that a prisoner whose guilt is established by a regular verdict is to escape punishment altogether because the court committed error in passing the sentence. If this court sanctioned such a rule, it would fail to perform the chief duty for which it was established. ”
Home Page 151 U. S. 261
It is true that this language was used in a case pending in the supreme court of a state on writ of error, but if then the court would send the case back to have the error, not touching the verdict, corrected and justice enforced, there is the same reason why such correction should be made when the prisoner is discharged on habeas corpus for alleged defects of jurisdiction in the rendition of the judgment under which he is held. The end sought by him — to be relieved from the defects in the judgment rendered to his injury — is secured, and at the same time the community is not made to suffer by a failure in the enforcement of justice against him.
The court is invested with the largest power to control and direct the form of judgment to be entered in cases brought up before it on habeas corpus. Section 761 of the Revised Statutes, on this subject provides that:
“The court, or justice, or judge shall proceed in a summary way to determine the facts of the case by hearing the testimony and arguments, and thereupon to dispose of the party as law and justice require.”
It would seem that in the interest of justice and to prevent its defeat, this Court might well delay the discharge of the petitioner for such reasonable time as may be necessary to have him taken before the court where the judgment was rendered, that the defects, for want of jurisdiction, which are the subject of complaint in that judgment may be corrected. Medley, Petitioner, 134 U. S. 160 , 134 U. S. 174 .
In the case of Coleman v. Tennessee, 97 U. S. 509 , a party who had been convicted of a capital offense, and the judgment had been confirmed by the Supreme Court of that state, was discharged by judgment of this Court because it was held that the state court had no jurisdiction to try a soldier of the army of the United States for a military offense committed by him while in the military service, and subject to the articles of war. But as it appeared that the prisoner had been tried by a court martial regularly convened in the army for the same offense, and sentenced to be shot, and had afterwards escaped, this Court, in reversing the judgment of the Supreme Court of Tennessee, stated that that court could turn the prisoner over to the military authorities of the United States. He was so turned
Home Page 151 U. S. 262
over, and the punishment was commuted to life imprisonment, and he was sent to Fort Leavenworth to serve it out.
In some cases, it is true that no correction can be made of the judgment, as where the court had, under the law, no jurisdiction of the case — that is, no right to take cognizance of the offense alleged — and the prisoner must then be entirely discharged; but those cases will be rare, and much of the complaint that is made for discharging on habeas corpus persons who have been duly convicted will be thus removed.
Ordered that the writ of habeas corpus issue, and that the petitioner be discharged from the custody of the warden of the penitentiary at Anamosa, in the State of Iowa, but without prejudice to the right of the United States to take any lawful measures to have the petitioner sentenced in accordance with law upon the verdict against him.
Contributors and Attributions
- Authored by : US Government. Located at : https://supreme.justia.com/cases/federal/us/151/242/case.html . License : Public Domain: No Known Copyright | 5,814 | common-pile/libretexts_filtered | https://biz.libretexts.org/Bookshelves/Constitutional_Law/Constitutional_Law_(Lumen)/10%3A_Punishment_and_the_8th_amendment-_What_constitutes_cruel_and_unusual_punishment/10.07%3A_In_Re_Bonner__151_US_242_(1894) | libretexts | libretexts-0000.json.gz:43876 | https://biz.libretexts.org/Bookshelves/Constitutional_Law/Constitutional_Law_(Lumen)/10%3A_Punishment_and_the_8th_amendment-_What_constitutes_cruel_and_unusual_punishment/10.07%3A_In_Re_Bonner__151_US_242_(1894) |
4VmiWAA2yzaTo9MR | Canadian History: Pre-Confederation - 2nd Edition | Chapter 8. Rupert’s Land and the Northern Plains, 1690–1870
8.6 Fur Trade Wars
The two companies found themselves increasingly in conflict in the West. NWC forts and trading posts glared across rivers at their HBC opposites, strange mirror images of Euro-Canadian commercial activity in a land dominated by Ojibwa and Cree. Competition between the English company and Montreal traders had been bloody since before the Conquest; the fact that they were both saluting the Union Jack after 1763 did little to ameliorate feelings. Moves were made in 1790 on the part of the NWC’s leadership to have Britain end the HBC monopoly, but that effort came to nothing.
The Montreal Factions
Relations within the NWC itself were hardly placid. The costs associated with long-distance transportation of goods and personnel to and from Montreal ate into profits. Tensions rose between the “winterers” and the agents, resulting in reorganizations and then, in response, breakaway partnerships such as the XY Company (a.k.a. the New North West Company). The 1790s and the first decade of the 19th century saw the Nor’Westers’ profitability and share of the fur supply rise while their unity fractured and healed. Their accomplishments in the West were hurried and impressive.
The pace had been set by people like Peter Pond (c. 1740-1807), a bizarre and homicidal individual whose efforts in the West in the 1780s took him into the Athabasca system, a first for a non-Indigenous person and a seminal moment in the history of the NWC. A decade later (making good use of Pond’s maps) Alexander Mackenzie (1764-1820), another NWC agent, explored the river than now bears his name and then, four years later, he crossed the whole continent, emerging near the main village of the Nuxalk (Bella Coola). (Mackenzie was the first European to cross the continent; his accomplishment predates the American expedition of Lewis and Clark by a decade.)
The NWC subsequently sent out two other missions: one headed by Simon Fraser (1776-1862) in 1808 and the other by David Thompson (1770-1857) in 1811. In the process the company moved into what is now northern British Columbia, what Fraser called New Caledonia. A few years later they closed the loop by purchasing John Jacob Astor’s Fort Astoria in 1812, which transferred to the NWC the Pacific Fur Company’s (PFC) control of posts reaching as far north as Thompson Rivers Post (Fort Kamloops). This expansion on the part of the NWC carved a path running northwest from Lake of the Woods to the Mackenzie River, right across the southwesterly course of the HBC’s growth. Repeatedly the companies’ representatives would come to blows.
The Western Nations
This situation was not assisted by a change in Indigenous attitudes toward trade. For peoples like the Dënesųlįné (Chipewyan) and the most northwestern of the Cree, having a trading post on their doorstep or even just somewhat nearer to their territory was an important advantage. Mackenzie reported that such groups normally travelled hundreds of miles to trade, journeys that took them away from their homelands, their hunting, and their other customary practices. They were, therefore, happy to encounter forthcoming traders who would “relieve them from such long, toilsome, and dangerous journies; and were immediately reconciled to give an advanced price for the articles necessary to their comfort and convenience.”[1]
Others were not so favourably impressed. The Niitsitapi and A’aninin (Grôs Ventres) nursed a growing hostility toward the fur traders who were supplying their Cree adversaries with arms. Conflict broke out sporadically. Events in the cordillera region took a similar turn from 1795 when the Ktunaxa (Kutenai) and Salis (Flathead) acquired guns from the NWC and American traders for use (successfully in 1810 and 1812) against their Piikáni (Piegan) enemies. The Piikáni thus joined the ranks of First Nations embittered against the newcomers. Even the Cree turned on the Euro-Canadians. In 1779 at Fort Montagne d’Aigle on the Saskatchewan River and again in 1781 at Fort des Trembles on the Assiniboine River, the Cree demonstrated their unwillingness to be cowed by arrogant traders.[2] The possibility arose in 1779-80 that the western Plains people — whose lands were increasingly saturated with fur traders of varying moral quality — would turn the newcomers out of the Plains entirely. Smallpox intervened in 1780 and further serious talk of a clearing of the West did not arise.
Conflict in the northwest was endemic after the fall of Wendake and the Beaver Wars, as Indigenous peoples worked toward a readjustment of territory and resources. The 18th century witnessed British American expansion into the trans-Appalachian west, causing further disruptions in traditional territories and invasions by displaced populations. Pressures were growing from all sides and they would not be relieved by landscape-scouring epidemics. Movement into new territories required adjustments and usually the occupants put up a fight. Some of the social and cultural changes that came with these movements and activities can only be described as revolutionary.
Key Takeaways
- Montreal traders were setting the pace in the West and entering into direct competition with the HBC in Rupert’s Land, regardless of the latter’s monopoly.
- Political and social changes in the Western nations were manifest in changing attitudes toward the Europeans and Euro-Canadians.
Attributions
Figure 8.12
A journey from Prince of Wales’s Fort, in Hudson’s Bay, to the northern ocean : undertaken by order of the Hudson’s Bay Company for the discovery of copper mines, a north west passage, & c. in the years 1769, 1770, 1771 & 1772 by Samuel Hearne is in the public domain.
Figure 8.13
Franklin map fur route<PHONE_NUMBER> c0c67ca7d3 o huge map (2) by Kayoty is in the public domain.
Long descriptions
Figure 8.12 long description: Title page of Samuel Hearne’s account of his travels in the North. The account is titled, “A journey from Prince of Wales’s Fort in Hudson’s Bay, to the Northern Ocean. Undertaken by order of the Hudson’s Bay Company, for the discovery of copper mines, a north west passage, etc., in the years 1769, 1770, 1771, and 1772.” The account was published in London in 1795.
Media Attributions
- A journey from Prince of Wales’s Fort in Hudson’s Bay, to the Northern Ocean. © 1795 by Samuel Hearne is licensed under a Public Domain license
- Barry M. Gough, “POND, PETER,” in Dictionary of Canadian Biography, vol. 5, (University of Toronto/Université Laval, 2003). Accessed November 26, 2014, http://www.biographi.ca/en/bio/pond_peter_5E.html . ↵
- Olive Patricia Dickason, Canada’s First Nations: A History of Founding Peoples from Earliest Times, 3rd edition (Don Mills: OUP, 2002), 175-6. ↵
Technically, the north-central part of what is now mainland British Columbia, as well as an administrative centre at Fort St. James. In practice, “New Caledonia” was used to refer to most, if not all, of the mainland colony.
Established at the mouth of the Columbia River in 1811 by John Jacob Astor’s Pacific Fur Company, Astoria was the first American position on the northwest coast. It was soon sold to the North West Company.
Fur trade venture created by New York–based entrepreneur John Jacob Astor. It established Fort Astoria on the northwest coast, but lasted for less than three years in the face of increased competition in the North American fur trade. Also known as the PFC. | 1,560 | common-pile/pressbooks_filtered | https://opentextbc.ca/preconfederation2e/chapter/8-6-fur-trade-wars/ | pressbooks | pressbooks-0000.json.gz:39839 | https://opentextbc.ca/preconfederation2e/chapter/8-6-fur-trade-wars/ |
JPCQBnyTgdVP3Jqo | Elements of descriptive geometry, with applications to isometric projection and othe forms of one-plane projection; a text-book for colleges and ingineering schools by O. E. Randall. | PREFACE
The aim of this treatise is to make a clear presentation of the theory of projection, to show the application of this theory as a medium of expression, and by the discussion and proof of a great variety of problems to enable the student to make a ready and intelligent use of this medium in the representation of all forms of magnitudes.
As by far the greater part of practical drafting is done from the standpoint of the third quadrant, there seems to be no good reason why the principles of descriptive geometry, which are so directly and extensively applied in practice, should not also be presented from the standpoint of the same quadrant.
from the third quadrant.
In the establishment of principles great effort is made to be explicit ; but in the application of these principles, for which purpose a great many unsolved problems are assigned, the student is left largely to his own resources^
As the principles of projection are fundamental in all branches of drafting, it follows that no attempt at extensive application of these principles in such subjects as machine drawing, gearing, architectural drawing, etc., should be made until the principles themselves have been thoroughly established. For this reason the attention of this work is largely confined to theoretical considerations, although a number of simple practical applications such
treated as applications of descriptive geometry.
It is hoped that the system of notation which is introduced will be found both simple and expressive; and that the method of locating given parts which may be employed in the assignment of work in the recitation room and in the drafting room will be found usefiil.
DEFINITIONS AND ASSUMPTIONS
1. The Subject defined. Descriptive geometry is that branch of mathematics which seeks, through the medium of an exact process of graphic expression, to represent geometrical magnitudes which occupy given positions in space, and also through the same medium of expression to solve such problems as relate to these magnitudes.
2. Representation of Magnitudes of Two Dimensions. A magnitude of two dimensions, such as a plane geometrical figure, may be easily and directly represented, graphically, upon a single plane, since every characteristic of such a magnitude may be determined from a single standpoint of observation, and the whole may be outlined upon the very plane in which the magnitude exists.
problems in plane geometry furnish an illustration of this fact.
3. Representation of Magnitudes of Three Dimensions. A magnitude of three dimensions does not exist in a single plane, neither can its characteristics be completely determined from a single standpoint of observation ; therefore the process of representation must necessarily be different from that employed in connection with magnitudes of two dimensions.
4. Projection. Since the points and lines of magnitudes of three dimensions do not exist in a single plane, as is the case with magnitudes of two dimensions, it will be necessary to determine some plane of representation and to establish some process by which reference to this plane may be made.
2 DESCRIPTIVE GEOMETRY
The plane of representation, or the plane upon which the representation is made, is called the plane of projection^* and the process by which reference to this plane is made is called projection.
tion for the observer, and a plane of projection.
When the point of sight and the plane of projection are given, the projection of an object, for simplicity a point, is accomplished when the point is literally thrown forward along its visual rayf until it rests upon the plane. In other words, the projection of a point upon any plane is the intersection of the visual ray of the point with that plane.
The point may occupy a position between the observer and the plane of projection, or the plane of projection may stand between the observer and the point; but in either case the projection of the point is found by the process stated above.
point and its projection will be identical.
5. Systems of Projection. It is evident that the character of the projection of a magnitude, which consists of a collection of points, will depend upon the relative positions of the magnitude, the observer, and the plane of projection.
There are two principal systems of projection, depending upon the position of the observer with reference to the plane of projection, — the scenographic projection and the orthographic projection.
projection.
As this is the position which would naturally be assumed by an observer, the projection upon the plane will correspond with that made upon the retina of the eye, and the picture will be true to nature. This system is employed whenever it is desired to represent an object as it appears, rather than to show its exact dimensions ; but on account of difficulties attending the operation of the
projection, the system is not practicable for problematic work.
The orthographic projection — the system which will be employed throughout this work — is that system in which the point of sight is assumed at an infinite distance from the plane of projection.
In this system, since magnitudes are assumed within a finite distance of the plane of projection, visual rays to the various points of such magnitudes may be regarded as parallel lines, and may be assumed perpendicular to the plane of projection.
Under these conditions the orthographic projection of a point upon any plane is the point in which a straight line drawn through the point perpendicular to the plane pierces the plane.
6. Planes of Projection. As a rule it is not possible to learn all the characteristics of magnitudes of three dimensions from a single standpoint of observation, and for this reason more than one plane of projection is usually needed.
There are two principal planes of projection, — a horizontal plane called the horizontal plane of projection or H, and a vertical plane perpendicular to H and called the vertical plane of projection or V.
8. Quadrants. The planes H and V divide space into four right dihedral angles know^n as the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant.
The first quadrant is above H and in front of V, the second quadrant is above H and back of V, the third quadrant is below II and back of V, and the fourth quadrant is below II and in front of V.
9. Projecting Lines. In orthographic projection the visual rays are called projecting lines, and are assumed perpendicular to the plane on which projection is made.
12. Revolution of the Planes of Projection. The primary position of H is horizontal, and the primary position of V is vertical, giving horizontal and vertical projections on two distinct planes perpendicular to each other.
In order that projections upon // and V may be represented upon a single plane, one of the planes of projection is revolved about G-L as an axis until it is coincident with the other.
dicular to V and is called the vertical projecting line of M,
iV is a point in the second quadrant. Its horizontal projection is n,, and its vertical projection is n". The line N-n^f is perpendicular to H and is called the horizontal projecting line of N, The line N-n'' is perpendicular to V and is called the vertical projecting line of iV.
O is a point in the third quadrant. Its horizontal projection is o^p and its vertical projection is o". The line O-o^^ is perpendicular to H and is called the horizontal 'projecting line of 0. The line 0-(?" is perpendicular to V and is called the vertical projecting line of 0.
P is a point in the fourth quadrant. Its horizontal projection is jt?„ and its vertical projection is p". The line P-p,, is perpendicular to H and is called the liorizontal projecting line of P. The
line of F.
It will be noticed in Fig. 1 that the horizontal and vertical projecting lines of a point determine a plane which is perpendicular to both H and V and is therefore perpendicular to G-L ; also that the straight lines in which this plane intersects H and V are perpendicular to G-L at the same point and pass respectively through the horizontal and vertical projections of the point.
Observe that when the horizontal and vertical projections of a point are given, the point itself is definitely located, for the horizontal and vertical projecting lines, determined by the projections of the point, lie in the same plane and intersect at the only point which can have its horizontal and vertical projections at the points given.
Observe that the distance of a point from H is in each case indicated by the distance of its vertical projection from G^-i, and that the distance of the point from V is in each case indicated by the distance of its horizontal projection from G-L.
projections coincide with the point itself.
14. Representation of the Point upon H and V in their Position of Coincidence. In Fig. 2 the projections m,,, m'^; riff^n"; Of,,o"; and Pfn P" ^^® those previously found in Fig. 1 and represent points in the first, second, third, and fourth quadrants respectively.
If the plane H. be revolved about G-L as an axis until that portion of H back of V falls on V above //, and that portion of If in front of V falls on V below ff, the point m" will remain stationary, while the point m,, will move in the arc of a circle with a as a center, and fall at m, in the line m"-a produced.
The point n" will remain stationary, while the point n,, will move in the arc of a circle with 5 as a center, and fall at n^ in the line 6-n" produced. The point o" will remain stationary, while the point o,, will move in the arc of a circle with (^ as a center, and fall at o^ in the line o"-d produced.
regarding the plane of the paper as vertical, represents both that portion of V above H and that portion of H back of F, and where that portion of the plane of the paper below G-L represents both yO, that portion of V below
falls upon that portion of
H in front of F, the horizontal projections will remain stationary, while the vertical projections will move in arcs of circles with centers in G-L^ and fall upon H in straight lines drawn through the corresponding horizontal projections perpendicular to G-L,
Fio. 4
After the revolution of the plane V into coincidence with // the projections will again be expressed as shown in Fig. 3, where that portion of the plane of the paper back of G-L^ regarding the plane of the paper as horizontal, represents both that portion of M behind V and that portion of V above H, and where that portion of the plane of the paper in front of G-L represents both that portion of If in front of V and that
It will be observed that whether we revolve H into coincidence with V or whether we revolve V into coincidence with H the result will be the same. When working on the
more natural.
Again referring to Fig. 1, let us first project the four points Jf, iV, 0, and P upon H alone. As the plane V is perpendicular to H it will in this projection appear as a straight line coincident with G-L., and the four projections will appear as shown in Fig. 4, where that portion of the plane of ^^,
the paper back of G-L represents IT back of F, and where that portion of the plane of the paper in front of G—L ^ — represents H in front of V. i^,
Now project the four points upon V alone. The plane H in this projection will appear as' a straight line coincident with G-L, and the four pi'ojections will appear as shown in Fig. 5, where that portion of the plane of the paper above G-L represents V above //, and where that portion of the plane of the paper below G-I^ represents V below H.
THE POINT, LINE, AND PLANE 9
other, and so that the two projections of each point shall fall upon the same straight line perpendicular to G-L^ the result will be precisely the same as that expressed in Fig. 3.
It will be observed that whether we revolve H into coincidence with F, or V into coincidence with H^ or whether the projections are made upon H and V independently and afterwards combined as shown above, the result is the same.
The object of the transformation is to make it possible to represent upon a single plane, projections which belong primarily upon two planes perpendicular to each other.
It is immaterial by which method the transformation is made ; the essential thing is that the student shall be able to pass in imagination, without any difficulty or hesitation, from the position of perpendicularity to that of coincidence, and vice versa.
Returning now to Fig. 3, which expresses the common result of the three methods of transformation, it will be noticed that when a point, as Jf, is in the first quadrant, its horizontal projection will be in front of G-L and its vertical projection will be above G-L ; that when a point, as iV, is in the second quadrant, its horizontal projection will be back of G-L and its vertical projection will be above G-L ; that when a point, as 0, is in the third quadrant, its horizontal projection will be back of G-L and its vertical projection will be below G-L ; that when a point, as P, is in the fourth quadrant, its horizontal projection will be in front of G-L and its vertical projection will be below G-L.
Conversely, referring to Fig. 3, if a horizontal projection, as w,, is situated in front of G-L., it will be known that the point M must be in front of F, that is, either in the first quadrant or in the fourth quadrant ; and if the vertical projection, as m', of the same point M is situated above (?-Z, it will be known that the point M must be above H^ that is, either in the first quadrant or in the second quadrant, and therefore it will be known that the point M must be in the first quadrant.
If a horizontal projection, as m,, is situated back of G-L^ it will be known that the point N must be back of F, that is, either in the second quadrant or in the third quadrant; and if the corresponding vertical projection, as n\ is situated above G-L^ it will be
known that the point JV must be above JI, that is, either in the first quadrant or in the second quadrant, and therefore it will be known that the point JV must be in the second quadrant.
If a horizontal projection, as o,, is situated back of G—L, it will be known that the point 0 must be back of F, that is, either in the second quadrant or in the third quadrant; and if the corresponding vertical projection, as o', is situated below G-L, it will be known that the point 0 must be below JJ, that is, either in the third quadrant or in the fourth quadrant, and therefore it will be known that the point 0 must be in the third quadrant.
If a horizontal projection, as jt?,, is situated in front of G-L, it will be known that the point F must be in front of V, that is, either in the first quadrant or in tlie fourth quadrant; and if the corresponding vertical projection, as />', is situated below G-L^ it will be known that the point P must be below i/, that is, either in the third quadrant or in the fourth quadrant, and therefore it will be known that the point F must be in the fourth quadrant.
It will be observed, from a comparison of Figs. 1, 2, and 3, that the horizontal and vertical projections of a point, in the transformed position shown in Fig. 3, must lie in the same straight line perpendicular to G-L.
It will be also observed that in the transformed position the distance of the horizontal projection of a point from G-L still indicates the distance of the point itself from F, and that the distance of the vertical projection of -a point from G-L still indicates tlie distance of the point itself from //.
15. To assume a Point at Random. To assume a point at random, assume its projections at random, provided they fall in the same straight line perpendicular to G-I^.
23. Projection of the Straight Line upon H and V in their Primary Position. As a straight line may be regarded as made up of an infinite number of consecutive points, the projection of the straight line will be the locus of the projections of these points.
The projecting lines of these points, since they are drawn from points in a straight line and perpendicular to a plane, constitute a plane perpendicular to the plane of projection.
The plane made up of these projecting lines is called the projecting plane of the line. If the projection is being made upon H, the projecting plane is called the horizontal projecting plane; and if the projection is being made upon F, the projecting plane is called the vertical 2yrojecting plane.
a straight line in the
third quadrant. 3/ and A^ represent any two points of the line but in no sense limit the length of the line. The horizontal projection of M is m^p and the vertical projection of M is m". The horizontal projection of A^ is n^j, and the vertical projection of A^is n". The horizontal projection of the line is then rrij-nj^, and the vertical projection of the line is m"-n".
The projection of a straight line, then, may be found by finding the projections of two of its points and drawing a straight line through these two projections. This will be true whatever the quadrant occupied by the line.
It will be noticed that when the horizontal and vertical projections of a straight line are given, the line is in general definitely determined, for the horizontal and vertical projecting planes determined by the projections of the line intersect in the only line which can have its horizontal and vertical projections in these lines.
It will be also noticed that the two projections of a line determine the position of the line with reference to H and V. For example, in Fig. 6 the vertical projection of the line shows that the line slopes downward to the right, the horizontal projection shows that the line approaches Fas it extends toward the right,
ward toward V to the right.
24. Representation of the Straight Line upon H and V in their Position of Coincidence. In Fig. 7 the projections 'mj-rtj^ and m"-n" are those previously found in Fig. 6, and represent a straight line in the third quadrant.
If the plane V remains stationary and the plane // be revolved as previously directed, the points m" and n" will remain stationary, while the points ?/?,, and w,, will revolve and fall at the points m, and n, respectively. The line m-n,, then, will represent the horizontal projection of the line M-N after H has been revolved, and the result may be expressed as shown in Fig. 8.
It will be easily seen that we shall obtain the same result if we allow the horizontal plane of projection to remain stationary and revolve Fas directed in Section 14.
It will be observed that the two projections of the line in Fig. 8 bear the same relation to G-L as they did in Fig. 6, and therefore reveal just as much in regard to the position of the line itself.
25. Projections of Straight Lines occupying Various Positions with Reference to H and F. In Fig. 9, M-N represents a straight line in the third quadrant perpendicular to H. The horizontal projection is a point m,, n,. The vertical projection is a straight line m^-n' perpendicular to G-L and parallel to M-N. That portion
the distance between M and N.
In the same figure 0-F represents a straight line in the third quadrant perpendicular to V. The vertical projection is a point o\ p'. The horizontal projection is a straight line o-p^ perpendicular to G-L and parallel to 0-P. That portion of the horizontal projection included between o, and p, is equal to the distance between 0 and P.
H and.F take their position of coincidence.
In Fig. 11, Jf-xY represents a straight line in the third quadrant, parallel to // but oblique to V. The vertical projection rnl-n' is parallel to G-L and at the same distance below G-L that M-N is
below H. The horizontal projection m-Uj is parallel to M-N^ and makes the same angle with G-L that M-N makes with V. That portion of the horizontal projection nicluded between m, and n^ is equal to the distance between 31 and N.
In the same figure 0-P represents a straight line in the third quadrant, parallel to Fbut oblique to H. The horizontal projection 0,-pj is parallel to G—L and at the same distance back of G-L that 0-P is back of V. The vertical projection o^-p' is parallel
to 0-P and makes the same angle with G-L that 0-P makes with H. That portion of the vertical projection included between o' and p^ is equal to the distance between 0 and P.
In Fig. 15, 3f-N represents a straight line located by the point M\n the third quadrant and by the point N in the first quadrant. The line pierces F at a' and pierces if at 5,. The section M-h^ of the line is in the third quadrant, the section h-a' is in the second quadrant, and the section a'-N is in the first quadrant.
In Fig. 17, Jf-A^ represents a straight line located by the point M in the fourth quadrant and by the point A^ in the second quadrant. The line pierces H at 5,, runs through the first quadrant, and pierces F at a^
26. Observations. When a straight line is parallel to a plane of projection, the projection upon this plane of any definite portion of the line will be equal in length to the portion in question.
If a straight line is parallel to H and oblique to F, its vertical projection will be parallel to G-L and its horizontal projection will make the same angle with G-L that the line itself makes with V.
If a straight line is parallel to Fand oblique to ^, its horizontal projection will be parallel to G-L and its vertical projection will make the same angle with G-L that the line itself makes with H.
projections at random.
28. To assume a Point upon a Straight Line. In Fig. 21 let m-Uf and m'—n' represent the horizontal and vertical projections of a straight line in the third quadrant. Assume one of the projections of the point, say the horizontal, o,, anywhere on the line m-Tif. Through o^ draw a straight line perpendicular to G-L and note its intersection o' with m'-7i'. The point o' is the vertical projection of the required point.
If a point is situated on a line, its horizontal projection must be on the horizontal projection of the line, and its vertical projection must be on the vertical projection of the line.
29. To assume Two Straight Lines which intersect. See Fig. 22. Draw at random the two projections, m,-w, and m'-n', of one of the lines. Assume upon this line any point as P. Through p, and p' respectively draw at random the horizontal and vertical
projections of the other line.
30. The Projections of Parallel Straight Lines. The projecting planes of parallel straight lines are necessarily parallel whatever the plane of projection ; therefore the intersections of these planes with the plane of projection, or in other words the projections of the lines, must be parallel.
31. The Projections of Straight Lines which are Perpendicular to Each Other. The projections of two straight lines which are perpendicular to each other are perpendicular to each other only when one or both of the lines are parallel to the plane of projection, since it is only under these conditions that the projecting planes of the lines are perpendicular to each other.
in the third quadrant perpendicular to H and 3 units from V.
34. Problem 10. Given a point Jf, 6 units hack of V and 4 units below //, also a point iV, 4 units in front of V and 4 units above H ; required to draw the projections of the straight line located by the points M and N.
37. Representation of the Plane. The line in which a plane intersects H is called the horizontal trace of the plane. The line in which a plane intersects V is called the vertical trace of the plane.
the plane in two points.
If either trace of a plane is parallel to G-L, the other trace must also be parallel to G-L, otherwise G-L would intersect the plane while it was parallel to a straight line in the plane.
As a plane is completely determined either by two intersecting straight lines or by two parallel straight lines, it is evident that a plane is definitely located bv its traces.
In Fig. 23, S-8^ represents the horizontal trace, and S-s' represents the yertical trace of a plane S which is oblique to both H and V. The plane is supposed to extend without limit in all directions, and therefore passes through all the quadrants, although in the diagram only that portion of the plane which lies in the third quadrant is represented.
It will be observed that the traces S-s^ and S-s' make the same angle with G-L after revolution as before, and therefore reveal just as much in regard to the location of the plane.
such traces are needed.
39. Representation of Planes occupying Various Positions with Reference to H and F. Fig. 25 represents a plane in the third quadrant, perpendicular to R but oblique to V. Under these conditions the vertical trace must be perpendicular to G-L and the horizontal trace must make the same angle with G-L that the plane makes with V.
Fig. 26 shows how the traces of the plane in Fig. 25 will appear after H and V take their position of coincidence, no change taking place in the relation of the traces to G-L.
Fig. 27 represents a plane in the third quadrant, perpendicular to V but oblique to H. Under these conditions the horizontal trace must be perpendicular to G-L and the vertical trace must make the same angle with G-L that the plane makes with H.
In all the foregoing cases, in order that the diagrams may be more easily understood, only limited portions of the planes have been taken into consideration ; but planes must be regarded as
lines which locate them.
When a plane is oblique to G-L^ as the plane S in Figs. 31 and 32, it passes through all the quadrants. Its horizontal trace extends both in front and back of G-L and its vertical trace extends both above and below G-L. The traces S-s^^ and S-s" limit that portion of the plane in the first quadrant, the traces S-s^ and S-s^' limit that portion of the plane in the second quadrant, the traces S-s^ and S-s' limit that portion of the plane in the third quadrant, and the traces S-s J J and S-s' limit that portion of the plane in the fourth quadrant.
41. To assume a Series of Parallel Planes. Since the intersections of a series of parallel planes by an oblique plane is a series of parallel straight lines, it follows that the horizontal traces of parallel planes must be parallel; also that their vertical traces must be parallel.
42. To assume a Straight Line in a Plane.
Principle. If a straight line in a plane pierces H it must pierce it in the horizontal trace of the plane, and if it pierces V it must pierce it in the vertical trace of the plane ; for the horizontal trace of the plane is the only line in common between the plane and H^ and the vertical trace of the plane is the only line in common between the plane and V,
Assume another point, as iV", anywhere in the vertical trace. The point n' is the vertical projection of this point, and the horizontal projection must be in G-L at n,.
^ the plane S^ it must be a point ^^*^^^ in the plane. The line 3I-N is ^^^.^y^^ : therefore a line of the plane.
the plane.
Principle. If a straight line is in a plane and is parallel to F, it will be parallel to the vertical trace of the plane, and its vertical projection will be parallel to the vertical trace of the plane.
upon this line.
44. Proposition 1. If a straight line is perpendicular to a plane, its horizontal projection will be perpendicular to the horizontal trace of the plane, and its vertical projection will he perpe7idicular to the vertical trace of the plane.
Proof. Since the line is perpendicular to the given plane, the horizontal projecting plane of the line must be perpendicular to the given plane. The horizontal projecting plane of the line is also perpendicular to H, and therefore since it is perpendicular
both to the given plane and to H^ it must be perpendicular to their intersection, which is the horizontal trace of the given plane. Since the horizontal trace of the given plane is perpendicular to the horizontal projecting plane of the given line, it must be perpendicular to any line of the horizontal projecting plane passing through its foot, as the horizontal projection of the given line.
By a similar course of reasoning in connection with the vertical projecting plane of the given line we may prove that the vertical projection of the given line must be perpendicular to the vertical trace of the given plane.
45. Proposition 2. If the two projections of a straight line are perpendicular respectively to the two traces of a given plane, the line itself will, in general, be perpendicular to the plane.
Proof. The horizontal projecting plane of the line is perpendicular to the horizontal trace of the given plane and therefore perpendicular to the plane. The vertical projecting plane of the line is perpendicular to the vertical trace of the given plane and therefore perpendicular to the plane. Since the horizontal and vertical projecting planes of the line are both perpendicular to the given plane, their intersection, which is the line itself, must be perpendicular to the plane.
to V and makes an angle of 60 degrees with IT.
48. Problem 15. Given a plane which makes an angle o/*30 degrees with H, and whose horizontal trace is parallel to G—L and 4 units hack of V ; required to draw the vertical trace.
determined in Problem 15.
50. Problem 17. Given a plane which is oblique to G-L, whose horizontal trace is back of F, and whose vertical trace is above H ; required to draiv the projections of a straight line in this plane.
SUPPLEMENTARY PLANES OF PROJECTION
52. Supplementary Planes of Projection. While H and Fare the principal planes of projection, projection may be made upon any plane which we may choose for that purpose. Any plane other than H OT V which is used as a plane of projection is spoken of as a supplementary plane of projection.
The most common supplementary plane of projection is a profile plane of projection, — a plane perpendicular to both K and V and consequently perpendicular to G-L.
It will also be observed that when the projections of a point upon IT, F, and F are given, the position of the point with reference to these three planes of projection is definitely determined.
Revolve the plane F about its vertical trace as an axis until that portion of the plane F in front of V falls on V to the left of the axis, and that portion of F back of V falls on V to the right of the axis.
Each profile projection will move in a plane parallel to IT, and in the arc of a circle with center in the axis. MF will fall upon V at a point as far to the left IR
This is the picture of the four points which the observer would have if he stood at an infinite distance to the right and looked along visual lines parallel to G-L. H would appear as a horizontal line corresponding with G-L in Fig. 35, and the vertical plane would appear as a vertical line corresponding with
Here points in the first quadrant have their profile projections to the left of the vertical line and above the horizontal line; points in the second quadrant have their profile projections to the right
of tlie vertical line and above the horizontal line; points in the third quadrant have their profile projections to the right of the vertical line and below the horizontal line; points in the fourth quadrant have their profile projections to the left of the vertical line and below the horizontal line.
Distances of points in front or back of V are indicated by the distances of their profile projections to the left or right of the vertical line. Distances of points above or below H are indicated by the distances of their profile projections above or below the horizontal line.
54. Representation of the Straight Line upon a Profile Plane of Projection. The profile projection of a straight line is determined by the profile projections of two points of the line.
Now if we revolve the profile phane of projection about its vertical trace P-p' until it coincides with F, MP will fall at mp^^ and NP will fall at np^\ The line mp^-np^' is the profile projection of M-N after the revolution.
equal to the distance of M from V. For the same reason NU will fall at nu^, and the line mu^^-nic^ will represent in revolved position the supplementary projection of the line M-N.
56. Revolution of the Supplementary Planes. After projection has been made upon a supplementary plane of projection the plane is revolved about either its horizontal trace or its vertical trace
The revolution is always made in such a way that that portion of the supplementary plane above R or in front of V, according as the axis is in H or in V, shall move toward the principal projections already made upon // or F, and that that portion of the supplementary plane of projection below H or back of V shall move in the opposite direction or away from the principal projections on H or V.
Illustration of this practice may be seen in Fig. 36, where the supplementary projection of M-N upon P back of V is revolved to the right, or away from the projection m'-n' ', also in Fig. 38, where that portion of the supplementary plane P in front of V is revolved toward the left and that portion back of V is revolved toward the right, the former toward and the latter away from the projection m'-n' ; again in Fig. 40, where that portion of the supplementary plane U below // is revolved toward the right, or away from the projection m-n,.
In case the supplementary plane is on the left of the magnitude, that portion of the supplementary plane above // or in front of F, according as the axis of revolution is in H or in F, is revolved, according to the rule, toward the right, or in a direction opposite to that assumed by supplementary planes on the right of the magnitude.
57. Problem 19. Given a straight line in the third quadrant and oblique to H and to V; required the supplementary projection of the line upon a profile plane of projection assumed on the left of the line.
58. Problem 20. Given a straight line in the second quadrant and oblique to H and to V; required the supplementary projection of the line upon a plane parallel to the horizontal projecting plane of the line and assumed on the left of the line. .
59. Problem 21. Given a straight line in the fourth quadrant and oblique to H and to V ; required the supplementary projection of the line upon a plane parallel to the vertical projecting plaiie of the line.
60. Problem 22. Given a plane parallel to G-L but oblique to H and to V; required the angle which the plane makes with H; also the angle which the plane makes with V. Solve by use of a supplementary profile plane of projection.
61. Problem 23. Given a plane parallel to G-L but oblique to H and to V; required the traces of a number of planes parallel to the given plane. Solve by use of a supplementary profile plane of projection.
62. Problem 24. Given a plane parallel to G-L and passing through the fourth^ first, and second quadrants ; required the traces of a plane parallel to the given plane and passing through the fourth, third, and second quadrants. Solve by use of a supplementary profile plane of projection.
NOTATION
63. To distinguish between a point in space and its projections on H and F, the point itself will be represented by the capital letter and its projection by the small letter.
64. The horizontal and vertical projections of a point, as M^ will be represented by m, and mJ respectively, and will be read m sub one and m prime one respectively.
65. If a point, as M, is made to occupy several positions in the same problem, its horizontal and vertical projections will be represented in order by w,, m'; m,,^ m"-, w,,,, m'^'-, etc.
67. If a point, as Jf, is revolved into H^ its revolved position will be represented by m^, and the vertical projection of the point in this revolved position will be represented by m^.
68. If a point, as Jf, is revolved into F, its revolved position will be represented by m^, and the horizontal projection of the point in this revolved position will be represented by m^.
71. If a point, as Jf, is projected upon a plane, as T, other than H or F, this projection will be represented by JfT, and the horizontal and vertical projections of this projection will be represented by mtf and mt' respectively.
72. If a point, as M^ is projected upon a plane, as P, and if this projection is projected upon another plane, as (>, the last projection will be represented by MPQ^ and its horizontal and vertical projections will be represented by mpq, and mpq^ respectively.
73. If in the last case MPQ should be revolved into //, its revolved position would be represented by mpqjj ; if revolved into F, its revolved position would be represented by mpq^,
represented by full lines.
76. The projections of given or required lines, when invisible, and the projections of all construction lines will be represented by broken lines consisting of dashes about \ inch in length and separated by very small spaces, thus :
METHOD OF LOCATING GIVEN PARTS
81. Coordinate Planes of Reference. Conceive a profile plane of projection F perpendicular to G-L^ passing through the center of the drawing space and cutting the plane of the drawing in a straight line to be known as the axis of Y.
will be considered minus distances.
82. The Point. A point will be located by giving its distances from P, F, and H. The distance of a point from P is the same as the distance of its horizontal projection from the horizontal trace of the plane P, or as the distance of its vertical projection from the vertical trace of the plane P. The distance of a point from V is the same as the distance of its horizontal projection from G—L. The distance of a point from H is the same as the distance of its vertical projection from G-L.
In giving the position of a point in space its distance from P will be mentioned first, its distance from V second, and its distance from H last. 31 = 2, 5, 4 means that the point 31 is 2 units to the right of P, 5 units in front of F, and 4 units above H ; that the horizontal projection of 31 is 2 units to the right of Y and 5 units in front of G-L ; that the vertical projection of 31 is 2 units to the right of Y and 4 units above G-L. The letters 3f, ^, 0, P, Q, and P will be used in connection with points.
83. The Straight Line. A straight line will be located by giving the position of two of its points. [Jf = — 2, 2, — 5 ; iV = 2, — 4, 6] indicates a straight line passing through the points 3f and JSF but not necessarily limited by them.
Straight lines will be specified by the letters of the points used in locating them ; for example, a straight line passing through the points M and N will be spoken of as the line M-N,
The angles which the horizontal and vertical traces make with G-L will always be measured, the former clockwise, the latter contra-clockwise, starting from G-L on the right of the vertex.
trace will be mentioned first.
T = 4, 30°, 45° means that the vertex is 4 units to the right of Y\ that the horizontal trace runs forward toward the right, making an angle of 30 degrees with G-L ; and that the vertical trace runs upward toward the right, making an angle of 45 degrees with G-L.
S = 0°, 4, 3 indicates that the traces are parallel to G-L ; that the horizontal trace is 4 units in front of G-L ; and that the vertical trace is 3 units above G-L.
Planes will be specified by the letters aS^, T, ZJ, and W. The horizontal traces will be represented hj S-s^, T-t^, d-Uf, W-w^; and the vertical traces will be represented by S-s\ T-t\ U-u', and W-w', the capital letter being placed at the vertex.
85. Scale. Problems of this book whose given parts are located with reference to three coordinate planes of projection have been designed to the scale of one quarter inch to the unit, and in the solution of these problems it will be found convenient to make use of tliis scale.
PROBLEMS RELATING TO THE POINT, LINE, AND PLANE
86. Introductory Statements. As a rule the solution of a problem will be divided into two parts : (1) the analysis, or general theory of solution, in which a clear and logical statement of the method of procedure without reference to any diagram will be made; and (2) the construction, or actual graphic work necessary in the solution, in which the suggestions of the analysis will be followed in order.
geometry should be checked.
A check in drafting is an application of some graphic process by which the accuracy of construction may be tested. No one can be absolutely sure of the accuracy of his results until they have been carefully tested.
The nature of the check for any particular problem may be determined by a study of the various conditions which must be satisfied by the processes of construction.
about a rectilinear axis occupying a definite position.
Principle. A point is being revolved about an axis when it moves in a plane perpendicular to the axis and retains a constant distance from the axis. A point situated in the axis will not move during revolution.
Through o,, the horizontal projection of O, draw o,-a, perpendicular to rrij-n,. This line must be the horizontal trace of the plane containing 0 and perpendicular to the axis, and therefore the plane in which 0 moves during revolution.
distance from the axis.
This distance is 0-a,, which is the hypotenuse of the rightangled triangle O-o-a^. The base of this triangle is equal to the distance of the horizontal projection of the point 0 from the axis, and the altitude is equal to the distance of the point 0 from H^ or, what is the same thing, the distance of the vertical projection of the point 0 from G-L. Therefore lay off from a^ upon a-o.
the revolved position of 0.
Construction, Fig. 45 shows how the work is done when the planes H and V occupy their position of coincidence. The line 0,-a, is drawn through o^ perpendicular to w -w, , and a^-Ojj is made equal to the hypotenuse of a right-angled triangle whose bas^ is equal to o^-a^ and whose altitude is equal to o'-h.
It will be noticed in Fig. 44 that if the point 0 is so situated that its horizontal projection falls on m-n^, the base of the triangle will vanish and the hypotenuse will be equal to the altitude. In such a case then the distance of the point from the axis, or the
required to revolve the point about the line as an axis into V.
Analysis. From what has been said in connection with Problem 25, it will be evident that the vertical trace of the plane of revolution must pass through the vertical projection of the given point and must be perpendicular to the given line ; also that the radius of the arc in which the point moves will be equal to the hypotenuse .^^ of a right-angled triangle whose base
This must be the vertical trace of the plane of revolution. Make a'-o^ equal to the hypotenuse of a right-angled triangle c-d-e^ whose base c-d is equal to o'-a^ and whose altitude c-e is equal to b-o^.
It will be noticed, as in Problem 25, that if the point 0 is so situated that its vertical projection falls on m'-n\ the base of the triangle will vanish and the hypotenuse will be equal to the altitude. In such a case then the radius of the arc of revolution will be equal to the distance of the horizontal projection of the point from G-L.
95. Problem 33. Given a straight line in space parallel to H^ also given a point in space ; required to revolve the point about the line as an axis until the plane of the point and the line is parallel to H.
given line and let 0 represent the given point.
As in Problem 25, o-a^ represents the horizontal trace of the plane containing the point and perpendicular to the axis, and therefore the plane in which 0 moves during revolution.
After revolution the horizontal projection of the point 0 must fall somewhere upon o-a, produced, and at a distance from a, equal to the hypotenuse of a right-angled triangle whose base is equal to o-a, and whose altitude is equal to o'-d'^ since the axis is not in H but at a distance b-d' below H.
The point o,, represents the horizontal projection of 0 in the required revolved position, and o", at the same distance below H as M-N and in a straight line through o,^ perpendicular to G-L^ represents the vertical projection of 0 in this position.
96. Problem 34. Given a straight line in space parallel to V, also given a point in space ; required to revolve the point about the line as an axis until the plane of the poiiit and the line is parallel to V. See Fig. 48-
97. Problem 35. G-iven a straight line in space parallel to G-L, also given a point in space; required to revolve the point about the line as an axis until the plane of the point and the line is parallel to H^ and again until the plane of the point and the line is parallel to V.
Fig. 50
constant distance from the axis M-N, the horizontal projection o, of the point must move in the arc of a circle with center at the point where the axis pierces H; and its vertical projection o' must move in a straight line o'-o'" drawn through o' parallel to G-L.
Construction. Fig. 5 0 shows how the work is done when the planes ^and V occupy their position of coincidence. The line m'-n' represents the vertical projection of the given line, and the point m, represents the horizontal projection of the same line. The points o, and o' represent the two projections of the given point in its first position.
With m, as a center and with m-Oj as a radius draw the circle Of—Of-Offf, This circle represents the path of the horizontal projection of the point during revolution. Through o' draw the straight line o'-o'" parallel to G-L. This line represents the path of the vertical projection of the point during revolution.
Now when 0 occupies such a position that its horizontal projection falls at o„, its vertical projection will take the position o" in a straight line through o^^ perpendicular to G-L.
45 degrees and 135 degrees.
101. Problem 39. Given a straight line perpendicular to F, also given a point in space ; required to revolve the point about the line as an axis.
Analysis and Construction, In Fig. 51 let M-N represent the given line, and let 0 (Op o') represent the given point. Since the point 0 must move in a plane perpendicular to M-N and therefore parallel to F, and since the point 0 must retain a constant distance from the axis M-N^ the vertical projection of the point, namely o^ must move in the arc of a circle with center at the point where the axis pierces F; and its horizontal projection o, must move in a straight line o-o^, drawn through o, parallel to G-L. Now if the point 0 occupy the several positions indicated in the diagram, the projections will fall at Op (?'; o,p o"\ 0,,,, o'" ; etc.
103. Problem 41. Given the straight line [Jf = 0, 1, 6; iV^= 0, 6, 6] and the point 0 = 3, 4, — 2 ; required to revolve the poi7it 0 about M-N as an axis through arcs q/* 60 degrees and 90 degrees,
104. Problem 42. 6^^vew two intersecting straight lines, one of which is perpendicular to H and the other oblique to H; required to revolve the latter about the former as an axis.
Analysis and Construction. In Fig. 52 let M-N (m—n^, m'—n') represent the line perpendicular to H, and let M-0 (nif-Of, m'-o') represent the line oblique to J7.
move as explained in Problem 36.
When the line M-0 occupies such a position that its horizontal projection falls at m-o,,, the vertical projection of 0 will fall at o", and the vertical projection of the line in this position will fall at m'-o".
may be found.
105. Problem 43. Given two intersecting straight lines one of which is perpendicular to V and the other oblique to V; required to revolve the latter about the former as an axis.
Analysis and Construction. In Fig. 53 \QtM-N{m-nj, m'-n^) represent the line perpendicular to F, and let M-0 {m^-Oj, m'-o') represent the line oblique to V.
106. Problem 44. Draw the two projections of a straight line passing through the point M = — 4, — 4, 2, running parallel to V, and making ayi angle of QO degrees with If.
107. Problem 45. Draw the two projections of a straight line passing through the point Jf = — 4, 3, —1, running parallel to H^ and makiyig an angle of 45 degrees with V.
108. Problem 46. Given the straight line [M = — 4, 5, 1 ; iV= 4, 2, 6] ; required to find the true distance between M and iV, and to determine the angle which the line makes with H.
Analysis. Revolve the line about an axis through M perpendicular to H until the line is parallel to V. The vertical projection of any portion of the line in this new position will be equal in length to the assumed portion of the line itself, and the angle which this vertical projection of the line in this new position makes with G-L will indicate the angle which the line itself in true position makes with H.
109. Problem 47. Given the straight line [M = — 4, 5, 1 ; N — 4:^ 2, 6] ; required to find the true distance between the points M and iV, and to determine the angle which the line makes with V.
Analysis. Revolve the line about an axis through M perpendicular to V until the line is parallel to H. The horizontal projection of any portion of the line in this new position will be equal in length to the assumed portion of the line itself, and the angle which this horizontal projection makes with G-L will indicate the angle which the line itself in true position makes with V.
110. Problem 48. Draw the two projections of a straight line 5 units long, passing through the point M = 2, — 4, — 1, making an angle of ZO degrees with i/, and in such a position that its horizontal projection makes an angle of 45 degrees with G-L,
Analysis. First draw the projections of the line when it passes through the given point, is parallel to F, and makes the required angle with H. Then revolve the line about an axis through the given point perpendicular to H until the horizontal projection of the line makes the required angle with G-I^. The two projections of the line in this last position will be the required projections.
Construction. See Fig. 54. The projections of the point M are m,, m'. The projections of the line, when the line is parallel to V and makes an angle of 30 degrees with i/, are m-nfj and m'-n'\ where rrif-n,, is parallel to G-L and where m'-n" is 5 units long
When the line is revolved to its final position, ?i,, will move in an arc of a circle to n,, and n'^ will move in a straight line parallel to G-L., to 7i'. The required projections are then
The line just located is in the third quadrant and runs from the given point downward to the left and toward V,
114. Problem 52. Draw the two projections of a straight line 4 units long, passing through the point Jf = 1, — 1, — 3, 7naking an angle of 45 degrees with F, and in such a position that its vertical projection makes an angle of 60 degrees with G-L.
Analysis. First draw the projections of the line when it passes through the given point, is parallel to H., and makes the required angle with V. Then revolve the line about an axis through the given point perpendicular to F, until the vertical projection of the line makes the required angle with G-L. The two projections of the line in this last position will be the required projections.
to H and makes an angle of 45 degrees with F, are m-n,^ and m'-n"^ where m,-n,j is 4 units long and makes an angle of 45 degrees with G-L^ and where mJ-n" is parallel to G-L,
When the line is revolved to its final position, n" will move in the arc of a circle to n'^ and n,, will move in a straight line parallel to G-L, to Uj. The required projections are then m-n, and m'-n'.
118. Problem 56. Draw the two projections of a straight line 6 units long, passing through a point M = 0, —3, —1, makiiig an angle o/ 60 degrees with H, and lying in a profile plane.
Analysis. First draw the projections of the line when it passes through the given point, is parallel to F, and makes the required angle with H. .Then revolve the line about an axis through the given point perpendicular to H until the horizontal projection of the line makes the proper angle with G-L (see Section 104).
119. Problem 57. Given a rectangular card whose dimensions are 6 units by 4 units, whose surface is parallel to F, whose long edges are perpendicular to If, and whose upper right-hand vertex is a point B = 2, — 1, — 1 ; required (1) to draw the two projections of the card in the given position^ and (2) to revolve the card about its right-hand vertical edge as an axis, through angles of SO degrees, 45 degrees, 60 degrees, and 90 degrees, and to draw the corresjjonding projectio7is.
Construction. See Fig. 56. The projections of the card in its first position are a-b^ and a'-b'-d'-e', where b^ and b' are the projections of B, where a'-b' is 4 units long, and where a'-e' is 6 units long.
When the card is revolved about B-D as an axis through an angle of 30 degrees, the two projections of the card are a^^-b^ and a"-b'-d'-e", where the angle a^-b^-a^^ is 30 degrees, and where a" and e" are in a straight line through a,, perpendicular to G-L.
determined when we remember that horizontal projections will
move in arcs of circles and that vertical projections will move in straight lines parallel to G-L (see Section 98).
angular card situated in the third quadrant^ ivhose dimensions are 6 units hy 4 units^ whose surface is parallel to H^ and whose long edges are perpendicular to V ; required (1) to draw the projections of the card in the given position^ and (2) to revolve the card about its left-hand edge as an axis, through angles of 30 degrees, 45 degrees, 60 degrees, and 90 degrees, and to draw the corresponding projections.
quadrant, whose dimensions are 6
units hy 4 units, whose surface is parallel to V, and whose long edges are perpendicular to II; required (1) to draw the projections of the card in the given position, and {2) to revolve the card about one of its vertical edges as an axis, through angles o/ 30 degrees, 45 degrees, 60 degrees, and 90 degrees, and to draw the corresponding projections.
122. Problem 60. Given a rectangular card whose dimensions are 5 units by 3 units, whose surface is parallel to II, whose long edges are parallel to V, and whose left-hand back vertex is A = — S, — 4, — 1 ; required (1) to draw the projections of the card in the given position ; {2) to revolve the card about its left-hand edge as an axis until the surface of the card is inclined 30 degrees to H, and to draw the corresponding projections ; and (S) to revolve the card in its last position about a vertical axis through J until the horizontal projections of the
In taking its second position the card is revolved about an axis through A perpendicular to V. The surface of the card will remain perpendicular to Fand its vertical projection will take the position a'-h" equal to a -ft', and making an angle of 30 degrees with a'-h'. Its horizontal projection will be a-bf-d^^-Cf, where A and U have made no change in position and where 5,, and c?„ fall in a straight line through b" perpendicular to G-L.
Upon a,, which makes no
change in position, construct the q rectangle a-bj^j-d^j-Cj, equal in every respect to a-b^-df-e, but having its edges inclined 45 degrees to G-L. This is the horizontal projection of the card in its final position.
The vertical projection of A will remain at a'. The vertical projection of B must be in a straight line through b" parallel to G-L^ and also in a straight line through 5,^, perpendicular to G-L, or at b'"'
The vertical projection of ^ must be upon a straight line through e' parallel to G-L, and also upon a straight line through e,f perpendicular to G-L, or at e'^.
123. Problem 61. G-iven a rectangular card whose dimensions are 6 units hy 4 units, whose surface is parallel to F, whose long edges are parallel to H, and whose right-hand upper vertex is jE" = 4, — 2, — 1 ; required (1) to draw the projectioyis of the card in the given position; \2) to revolve the card about its right-hand vertical edge as an axis until the surface of the card is inclined 30 degrees to F, and to draw the corresponding projections ; and (3) to revolve the card in its last position about an axis through E perpendicular to V until the vertical projections of the edges of the card are inclined 45 degrees to G-L, and to draw the corresponding projections.
125. Problem 63. Given an hexagonal card whose side is 3 units, whose surface is parallel to F, two of whose sides are parallel to H, and whose extreme left-hand vertex is A = — 4, — 1, — 4 ; required (1) to draw the projections of the card iri the given position ; {2) to revolve the card about a vertical axis through A until the surface of the card makes an angle of QO degrees with F, and to draw the corresponding projections ; and (3) to revolve the card in its last position about an axis through A perpendicular to V until the vertical projections of the sides which were parallel to H in the last position shall make an angle of 45 degrees with G—L, and to draw the corresponding projections.
In taking its second position the card is revolved about a vertical axis through A. The surface of the card will remain perpendicular to H and its horizontal projection will take the position «,-g,, equal to a^-e^, and making an angle of 60 degrees with a,-e^. Its vertical projection will be a'-b"-d"-e"-f'^-g", where a' has made no change in position, where b" is at the intersection of a straight line through b' parallel to G-L, with a straight line through bj^ perpendicular to G-L, where d" is at the intersection of a straight line through d^ parallel to G—L, with a straight line through dj, perpendicular to G-L, etc.
In taking its third position the card is revolved about an axis through A perpendicular to F. The vertical projection will change in position but not in character.
Upon a\ which makes no change in position, construct the polygon a'-b"'-d'"-e"'-f"'-g'" equal in every respect to a'-b"-d"e"-f"-g'\ but having the sides which were originally parallel to G-L now inclined at an angle of 45 degrees to G-L. This is the vertical projection of the card in its final position.
126. Problem 64. Given an hexagonal card whose side is 3 units, whose surface is parallel to H, two of whose sides are parallel to V, and whose extreme left-hand vertex is A = — 4, — 4, — 1 ; required (1) to draw the projections of the card in the given position; {2) to revolve the card about an axis through A perpendicular to V until the surface of the card makes an angle of 60 degrees with H, and to draw the corresponding projections ; and {3) to revolve the card in its last position about an axis tlirough A perpendicular to H until
Case 1. To find the poiyit in which the line intersects If.
Analysis. Since the point in which the line intersects H must be both in ^ and in the line, itself, its vertical projection must be both in G-L and in the vertical projection of the line, and therefore at their intersection. The horizontal projection of the required
point must be both in a straight line perpendicular to G-L through the vertical projection just found and also in the horizontal projection of the line, and therefore at their intersection.
given line.
Produce the vertical projection m'-7i' to meet G~L at a'. The point a' is by analysis the vertical projection of the required point. At a' draw a straight line perpendicular to G-L to meet the horizontal projection of the line at a„ which is both the horizontal
According to Section 55 the line mUj^-nUji is the supplementary projection of M-N. Produce mUjj-nUjj to meet the horizontal trace U-u, in au,^ which is the supplementary projection of the point in which M-N intersects //. According to Section 55 the points a, and au, should be in the same straight line perpendicular to U-u^.
Analysis. Since the point in which the line intersects V must be both in V and in the line itself, its horizontal projection must be both in G-L and in the horizontal projection of the line, and therefore at their intersection. The vertical projection of the required point must be both in a straight line perpendicular to G-L through the horizontal projection just found, and also in the vertical projection of the line, and therefore at their intersection.
vertical projection just found.
Construction. See Figs. 59 and 60. Produce the horizontal projection of the line to meet G-L at 6,. At this point draw a straight line perpendicular to G-L to meet the vertical projection of the line at h\ which is the required point.
Chech. See Fig. 60. Project M-N upon the supplementary plane IF, which is assumed parallel to the vertical projecting plane of M-N^ and proceed as in Case 1.
Analysis 1. If the straight line connecting the two points be revolved about its horizontal projection as an axis into H^ the line will be seen in its true length (see Sections 26 and 87).
Analysis 2. If the straight line connecting the two points be revolved about its vertical projection as an axis into F, the line will be seen in its true length.
Analysis 3. If the straight line connecting the two points be revolved about the horizontal projecting line of one of its points as an axis until the line is parallel to F, the vertical projection of the line in this revolved position will be equal in length to the line itself (see Sections 26 and 104).
Construction 2, See Fig. 62. Let M and N represent the given points. Following Analysis 4, revolve M-N about the vertical projecting line of M until M-N is parallel to H (see Section 105). M will remain stationary, but N will move, its vertical projection
here suggested may be checked by using one of the other methods.
135. Problem 73. Find the distance between the two points Jf = — 6, — 6, 2 and A^ = 6, 2,-4 hy Analysis 2.
136. Problem 74. Find the distance between the two points M =— Q^ 6, 2 and N— 4:^ — 4:^ — 4: by Analysis 3.
137. Problem 75. Find the distance between the two points Jf = 0, — 6, 1 and A^ = 0, 2, 8 by any method^ and check it by another.
Analysis. If we connect any two of the given points by a straight
line, such a line must lie in the required plane and must pierce H and V in the corresponding traces of the plane (see Section 42). A straight line connecting either one of the points just used with
other two, is a line of the required plane.
Construction. See Fig. 63. Let Jf, A, and 0 represent the three given points. Connect Jf and A" by a straight line and produce it to intersect H in a, and V in b'. The point a^ is a point in the
horizontal trace of the required plane, and the point h' is a point in the vertical trace. Connect N and the remaining point 0 by a straight line. The point e, in which N-0 intersects H is another point in the horizontal trace, and the point d' in which N-0 intersects V is another point in the vertical trace. S-s, drawn through a^ and e, is the horizontal trace of the required plane, and S-s' drawn through h' and d^ is the vertical trace.
straight lines, and to bisect the angle.
Analysis 1. Revolve the plane of the angle about its horizontal trace or its vertical trace into the corresponding plane of projection. The angle between the two lines will then be seen in its true size (see Section 87), and may be bisected.
Analysis 2. Revolve the plane of the angle about some straight line which is in the plane and parallel to one of the planes of projection, until the plane is parallel to that plane of projection. The projection of the angle upon this plane of projection will then be equal to the angle itself and may be measured and bisected.
Construction. See Fig. 64. Let Jf-iVand N-0., intersecting at iV, represent the two given lines. Following Analysis 1, produce M-N to meet H at a, and produce N-0 to meet H at b,. The line Sf-S-Sf through a, and 6, is the horizontal trace of the plane of the given angle. Revolve this plane about s^f-S-s^ as an axis into IT. The points a, and 5,, which are points in the sides of the angle and also in the axis, will remain stationary. The vertex N will fall at njj (see Section 87). The angle a-nj-b^ is the required angle. Bisect this angle by the line nj^-d, intersecting s^-S-s, at d,.
When the plane of the angle is revolved back to its original position, dj will remain stationary and N will take its old position. The horizontal projection of the bisector in true position will be at n^-d, and its vertical projection will be at n'-d'.
their traces are Jcnow7i.
Case 1. When the horizontal traces of the two planes intersect within the limits of the drawing and when the vertical traces of the same planes also intersect within the limits of the drawing.
Analysis. The intersection of the horizontal traces must be a point common to both planes and therefore a point in their intersection. For the same reason the intersection of the vertical traces must be another point in the required intersection.
Cheek. Connect any point in
jj the line of intersection with any point in the vertical trace of one of the planes, and note whether this line intersects IT in the horizontal trace of the same plane. Apply the same test with ref-
given planes whose horizontal
traces do not intersect within the limits of the drawing. The vertical traces intersect at a' horizontally projected at a,, locating one point in the required intersection. Pass an auxiliary plane U
parallel to V. The plane U cuts the plane iS in a straight line B-U parallel to S-s' and vertically projected in b'-e' parallel to S-s' (see Sections 30 and 41). The plane U cuts the plane T in the line D-E vertically projected in d'-e'. The point e' in which the two vertical projections intersect must be the vertical projection of the point in which the lines B-E and D-U intersect, and is, according to analysis, the vertical projection of a point in the required intersection. Since the point JS is in the plane £/, its horizontal projection e^ must be upon U-u^, and therefore at the intersection of U-Uf and a straight line through e' perpendicular to G-L.
Analysis. The given line must intersect the given plane in the line in which any auxiliary plane containing the given line intersects the given plane. The point in which the given line crosses this line of intersection must be the required point.
152. Problem 90. Find
the point in which the j^Zawe determined hy the two liyies \_M = — 6, 6, 6 ; .¥•= 0, 2, 1] and [il^= - 6, 6, 6 ; 0=2, 8, 4] is intersected hy the line [(^ = - 4, 2, 2 ; i^ = 2, 6, 8].
point from the playie.
Analysis. By Section 44 we know that the horizontal projection of the required line must be perpendicular to the horizontal trace of the given plane, and that the vertical projection of the required line must be perpendicular to the vertical trace.
The distance of a point from a plane is measured on a straight line drawn from the point perpendicular to the plane. If then we find the point in which such a line intersects the given plane, the distance from the given point to this point of intersection will be the required distance.
Construction. See Fig. 69. Let S represent the given plane and let 0 represent the given point. Through o, draw o^-d^ perpendicular to S-Sf and through o' draw o'-d' perpendicular to >S-s'. 0-D is the required line.
By Problem 89 find the point D in which the line 0-D intersects S. The distance 0-D^ which is found by revolving the horizontal projecting plane of 0-D about o^-d, into H (see Problem 72), is the required distance.
Chech. To tes^; the perpendicularity of the line, draw through D some line of the plane and note whether this line is perpendicular to 0-D. To test the distance of the point from the plane, revolve the vertical projecting plane of 0-D about o'-d' into V.
Principle. The projection of a straight line upon a plane is the line in which a plane drawn through the given line perpendicular to the given plane intersects the given plane (see Section 23).
Analysis 1. If through any point of the given line we draw a straight line perpendicular to the given plane, the plane of the given line and this auxiliary line will be the projecting plane of the given line, and will intersect the given plane in the required projection.
The projection of N upon S is NS^ horizontally projected at ns, and vertically projected at ns' . Therefore ms-ns, is the horizontal projection and ms'-ns' is the vertical projection of the required projection.
perpendicular to a given straight line.
Analysis. From Section 44 we know that the horizontal and vertical traces of the required plane will be perpendicular respectively to the horizontal and vertical projections of the given line. We know, then, the direction of each of the required traces. If a straight line be drawn through the given point parallel to either of these traces, it must be a line of the required plane, and, unless parallel to G-L^ will intersect one of the planes of projection in a point of the corresponding trace of the required plane. A straight line through the point thus found and perpendicular to the corresponding projection of the given line will be one of the required traces.
The other required trace will pass through the point in which the trace just found intersects G-L^ and will be perpendicular to the remaining projection of the given line.
Construction. See Fig. 71. Let
M-N represent the given line, and let 0 represent the given point. Through 0 draw 0-A parallel to the horizontal trace of the required plane. Since this horizontal trace is to be perpendicular to m,-
The point a' in which 0-A intersects F is a point in the vertical trace of the required plane, and S-s^ drawn through a' perpendicular to m'-n' is the required vertical trace. S-s^ drawn through >S^ perpendicular to m-n^ is the required horizontal trace.
Analysis, If through the given point we draw two straight lines parallel respectively to the two given lines, the plane of these two lines will be parallel to the two given lines, since a plane is parallel to a straight line when it contains a straight line parallel to that line.
Check. By Section 43 assume any point in the plane now determined. Through this point draw two straight lines, one parallel to one of the given lines and the other parallel to the other. The points in which these two lines intersect H and V should lie in the horizontal and vertical traces already located.
parallel to a given plane.
Analysis. The traces of the required plane will be parallel to the corresponding traces of the given plane, and will be fully known when one point in each trace is determined. A straight line through the given point and parallel to either trace of the given plane will be a line of
Analysis. Through any point of the first line draw a straight line parallel to the second line. The plane of the first line and the auxiliary line will be the required plane.
Construction. See Fig. 74. Let y¥-i\^ represent the line through which the plane is to be passed, and let 0-P represent the line to which the plane is to be parallel.
Analysis 1. If we pass a plane through the given point and the given line, and revolve this plane about one of its traces into the corresponding plane of projection, the line and the point will be shown in their true relation. From the revolved position of the point draw a straight line perpendicular to the revolved position of the line, and upon this line measure the required distance.
intersected by the given line. A straight line from this point of intersection to the given point will be perpendicular to the given line and will therefore be the line upon which the required distance may be measured.
Following Analysis 1, draw the line 0-P through 0 parallel to M-N and produce it to intersect if at pj. Find <x,, the point in which M-N intersects H. S-s,^- drawn through p^ and a,, is the horizontal trace of a plane
and <x, will remain stationary. Since A and Jtf are points of the line Jf-iV, <x,-m^is the revolved position of the given line.
Analysis. This problem is embodied in Problem 117, since in finding the shortest distance from a point to a straight line, a straight line is drawn from the given point perpendicular to the given line.
If in the solution of Problem 117, Analysis 1 is followed, a counter revolution will be necessary in order to determine the projections of the line required in Problem 120.
Construction. Making use of the results obtained in Fig. 75, revolve the plane S back to its original position. 0 will take the position ((?,, o') which it originally occupied, and B^ which is a point on M-N^ will move back in a plane perpendicular to S-s, until its horizontal projection takes the position hj and its vertical projection takes the position h' in the straight line througli h^ perpendicular to G-L.
which the line makes with its projection on that plane.
Analysis 1. By Problem 99 project the given line upon the given plane, and by Problem 80 measure the angle between the line itself and its projection.
Analysis 2. If through any point of the given line a straight line be drawn perpendicular to the given plane, it will intersect the given plane in one point of the projection of the given line upon this plane. The line itself will intersect the plane in another point of this projection. A straight line through the two points just found will be the projection of the line upon the plane.
The line itself, the projection of the line, and the straight line drawn perpendicular to the plane, together, form a right-angled triangle. In this triangle the line itself is the hypotenuse, the projection of the line is the base, and the straight line perpendicular to the plane is the altitude.
The oblique angle at the base of the triangle is the required angle, and since the triangle is right-angled the angle at the vertex must be the complement of the required angle.
Following Analysis 2, through some point of M-N, as M, draw M-B perpendicular to S and produce it to intersect j^ at h,. Find the point a, in which M-N intersects H. is the horizontal trace of the
189. Problem 127. To find the angle between two given planes.
A dihedral angle is measured by the plane angle formed by two straight lines perpendicular to the edge at the same point, one line lying in one face and the other line lying in the other face.
Analysis 1. Pass a plane perpendicular to the line of intersection of the two given planes. This plane will intersect the given planes in straight lines perpendicular to the line of intersection at the same point. The angle between these two lines is the required angle.
Analysis 2, Assume any point between the faces of the dihedral angle. Through this point draw two straight lines, one perpendicular to one face and the other perpendicular to the other face, /^y The angle formed by
(see Section 45). The line cut from >S^ by ?7, — the line forming one side of the required plane angle, — pierces H'dtd^; the line cut from T hj £/, — the line forming the other side of the same angle, — pierces IT at g,, and it only remains to find the vertex of the angle, which is the point in which U is intersected by A-B.
U will cut the horizontal projecting plane of A-B in a straight line perpendicular to A-B^ piercing H at c,, and intersecting A-B at the vertex of the angle sought.
Revolve the horizontal projecting plane of A-B about a-h^ as an axis, into H. The line a,-hjj is the revolved position of A-B^ and c-fjifj drawn through c, perpendicular to a-hj^ is the revolved position of the intersection of U and the horizontal projecting plane of A-B, The point /^^ is the revolved position of the vertex, and
With the vertex in true position revolve TJ about TJ-u^ as an axis, into H, The points d^ and e^ will remain stationary and the vertex F will fall at /y, where c^-f^^ is equal to Cj-fjjj^.
Suggestion. In this case the edge of the dihedral angle is the horizontal trace of the given plane. The auxiliary plane, which is perpendicular to the edge, is therefore perpendicular to II. Its horizontal trace will be perpendicular to the horizontal trace of the given plane, and its vertical trace will be perpendicular to G-L.
195. Problem 133. Griven either trace of a plane and the angle which the plane makes with the corresponding plane of projection ; required to determine the other trace.
angle which the plane makes with H are given.
Any plane perpendicular to this horizontal trace will cut from the plane whose vertical trace is sought a straight line, and from H another straight line, both of which will be perpendicular to the horizontal trace at the same point. These two lines will form a plane angle measuring the given dihedral angle, and if revolved into H about the side in iT, will be seen in true size.
Through any point of the given horizontal trace draw two straight lines in H^ the first perpendicular to the trace and the second making an angle with the first equal to the measure of the given dihedral angle.
Revolve the plane of these two lines about the first line as an axis until perpendicular to //. The second line in this position must be a line of the plane whose vertical trace is sought, and must pierce F at a point in this trace.
Construction. See Fig. 78. Let S-s, represent the given horizontal trace, and let the angle A represent the measure of the given angle which the plane makes with //.
Revolve the plane of the three
lines, b-df^ b^-djj^ and d-dj^ about b-df as an axis until the plane occupies its true position, which is perpendicular to H. The line d-dfj will take the position d-d' perpendicular to G-L^ and the point d„ will take the position d' on the line d-d'^ and at the distance d,-djj below G-L. The point c?', then, is the point in which B-D^ in true position, pierces F, and is therefore a point in the required vertical trace. S-d'-s' is the required vertical trace.
In case the given horizontal trace does not intersect G-L within the limits of the drawing, assume another point upon the horizontal trace and proceed as above to find another point in the vertical trace.
Check. Assume some point on the horizontal trace other than those already used, and proceed as above to locate an additional point on the vertical trace already determined.
196. Problem 134. Given the horizontal trace [S = — 4, 3, 0; s, = 4, 6, 0] of a plane S, and given the angle 60 degrees which the plane S makes with H; required the vertical trace of the plane S.
197. Problem 135. Given the vertical trace [^ = —5, 0, 0; s' = 8, 0, 5] of the plane S, and given the angle 30 degrees which the plane S makes with V; required the horizontal trace of the plane S.
198. Problem 136. Given the horizontal trace [S = —b, —4, 0; s^ = 5, — 4, 0] of the plane S, and given the angle 60 degrees which the playie S makes with H ; required the vertical trace of the plane S.
to both.
Analysis 1. Through one of the lines pass a plane parallel to the other line, and project the second line upon this plane. This projection must be parallel to the second line and intersect the first line. At this point of intersection erect a straight line perpendicular to the plane.
This line must be perpendicular both to the first line and to the projection of the second line. It will remain in the projecting plane of the second line and therefore intersect the second line. It will be perpendicular to the second line since it is perpendicular to the projection of the second line on a plane to which the second line is parallel. It is therefore perpendicular both to the first line and to the second line.
Analysis 2. In case we are required to find simply the shortest distance between two straight lines not in the same plane, we may proceed as follows : Through any point of one of the lines pass a plane perpendicular to the other line. Project the first line upon this plane. The distance from the point in which the second line intersects the plane to the projection of the first line upon the plane is the required distance.
Following Analysis 1, draw through M-N the plane S parallel to 0-P. To do this, draw through any point of M-N., as 2>, the line D-E parallel to 0-P. Find the point e, in which D-E pierces
H', also find the point a, in which M-N pierces IT, thus locating the horizontal trace S-Sj. Find the point h' in which M-N pierces F; also find the point /' in which D-E pierces F, thus locating the vertical trace S-s'.
Project 0-P upon S, To do this, draw through any point of 0-P, as 7f, the line K-KS perpendicular to aS', and find its intersection, KS^ with S. The point KS is one point in the projection of 0-P upon S (see Section 161), and since 0-P is parallel to S, KS-X drawn parallel to 0-P is the required projection.
At the point X, where KS-X crosses Jf-iV, draw X- Y perpendicular to S (see Section 154), and note the point Y in which it intersects 0-P. X-Y is the required line, and if the true length of its intercept between M-N and 0-P is desired, it may be found by Problem 72.
Check. The points x^ and x'., which are found independently, should fall in the same straight line perpendicular to G-L. The same should be true of y, and y'.
A more severe check would be made by drawing the auxiliary plane, in the first part of the construction, through 0-P parallel to M-N instead of through M-N parallel to 0-P,
entirely independent of it.
In the above problem, if one of the two given lines is perpendicular to the plane of projection, the required line will be parallel to the plane of projection, and its own projection will pass through the point projection of the line which is perpendicular to the plane and will be perpendicular to the projection of the other given line.
If one of the two given lines is parallel to the plane of projection, the projection of the required line upon this plane will be perpendicular to the projection of the parallel line upon this plane.
200. Problem 138. G-iven the two straight lines [Jf= — 5, 3, 5 ; N = 5, 3, 5] and [0 = - 4, 2, 6 ; P = 4, - 4, - 3] ; required the projections of the straight line perpendicular to both.
201. Problem 139. G-iven the two straight lines [M= — 5, 3, 5; ]Sr= 5, 3, 5] and [0 = 2, -Q, 1; F = 2, 1, - 6] ; required the projections of the straight line perpendicular to both,
202. Problem 140. Given the two straight lines [M= — 5, —6, - 6 ; iV^= 3, 1, - 2] and [0 = -i, - 6, - 3 ; P = 4, - 7, - 6] ; required the shortest distance between the two lines.
GENERATION AND CLASSIFICATION OF LINES
203. Generation of Lines. We may regard a line as the generation resulting from the movement of a point which in the course of the generation occupies an infinite number of consecutive positions at infinitely small distances apart.
The portion of the line generated by the point while moving from one position to its consecutive position is called an elementary line^ and while in theory it may be regarded as having length, practically speaking it has none.
movement to a plane, the line is called a curve of double curvature.
205. Curves of Single and of Double Curvature. The character of a curve, whether of single or of double curvature, will depend upon the law which governs the motion of the generating point, and there may be as many distinct curves as there are distinct laws governing the motion of a point.
If the generating point moves in a plane and retains a constant distance from a fixed point in the plane, it will generate a curve of single curvature called the circle.
If the generating point moves in a plane and in such a way that the sum of its distances from two fixed points in the plane is a constant quantity, it will generate a curve of single curvature called the ellipse.
If the generating point moves in a plane, and in such a way that its distance from a fixed point in the plane is equal to its distance from a fixed straight line in the plane, it will generate a curve of single curvature called the parabola.
If the generating point moves in a plane, and in such a way that the difference of its distances from two fixed points in the plane is a constant quantity, it will generate a curve of single curvature called the hyperbola.
If the generating point moves in such a way as to retain a constant distance from a fixed straight line, and to have a uniform motion both around and in the direction of the straight line, it will generate a curve of double curvature called the helix.
206. Representation of Curves. Curved lines like straight lines may be represented by their projections on IT and F, and when so represented they are in general definitely determined.
ing point in its consecutive positions, and are usually curved lines.
If the curve is of single curvature and its plane is parallel to the plane of projection, its projection upon this plane is a curve of the same character and magnitude as the original curve.
The projection of a curve of double curvature is always a curve whatever the relation of the curve to the plane of projection. The projection of the helix upon a plane perpendicular to its axis is a circle.
207. Tangents to Curves. A straight line is tangent to a curve at a given point when it represents the rectilinear path in which the generating point is moving at the instant it passes through the point of tangency.
In Fig. 80 let A-B-D represent a curve generated by a point moving under some law. Suppose that when the generating point reaches the position i?, the law under which it is moving ceases to act and the point is allowed to move freely in the direction B-E^ in which it is moving at this instant. The straight line B-E is tangent to the curve at the point B.
Or, a straight line is tangent to a curve at a given point when the line contains the given point and its consecutive point. In Fig. 81 let B represent any point on the curve A-B-D. Through B draw any secant, as B-F^ cutting the curve at B and F. Now if the point B remain fixed and the point F be made to move along the curve toward B^ the secant will gradually approach the position of a straight line tangent to the curve at the point B. Finally, when the point i^ has taken the position consecutive to B^ or practically the position B itself, the line B-F will take the position B-E and be tangent to the curve at the point B, Two curves are tangent to each other when they have two consecutive points in common, or when they are both tangent to the same line at a common point.
single curvature lies in the plane of the curve.
If two lines, straight or curved, are tangent to each other, their projections will also be tangent to each other, since the projections of the two ^ . consecutive points common to the two lines will also be consecutive and be common to the two projections of these lines.
Construction.^ In Fig. 82 let A-B and D-E represent the axes of the ellipse, let F and F' represent the foci of the ellipse, and let P represent the point assumed on the curve.
point assimied on the curve.
Construction. In Fig. 83 let A-C represent the axis of the parabola, let A-B represent the directrix, let D represent the vertex, and let P represent the point assumed on the curve.
Construction. In Fig. 84 let A-B represent the axis of the hyperbola, let F and F' represent the foci, let A and B represent the vertices of the two branches of the curve, and let P represent the point assumed on the left-hand branch of the curve.
If a curve is rolled out upon a rectilinear tangent to the curve, so that the consecutive points of the curve fall consecutively upon the tangent, that portion of the tangent covered between the first and last points of contact will represent the rectification of that portion of the curve between these same points.
The work of rectification is accomplished graphically by dividing the curve into a large number of small arcs, so small that the chords of the arcs may for practical purposes be taken as equal in length to the arcs themselves, and by taking the summation of these chords.
In Fig. 85 let it be required to rectify the portion A-B of the curve A-B-D. Set the dividers at some sufficiently small distance and apply this distance as a chord successively to the curve, starting with the point A. In this particular case the chord is applied six _^.____________ times, leaving the little arc Q-B whose chord
times to the straight line A-D^, starting with J,, adding to the sum the little distance 6 -^^ which is the chord measure of the little arc Q-B on the original curve. The distance A^-B, is the rectified length of the arc A-B.
213. The Helix. The helix is a curve of double curvature generated by a point moving uniformly both around and in the direction of a given straight line from which it retains a constant distance.
pitch of the helix.
If, to an observer looking along the axis in that direction in which the generating point is moving, the circuit of the generating point about the axis is clockwise, the helix is called a righthanded helix.
the axis of the helix, assumed for convenience perpendicular to H,
With a^ as a center and with a-dj as a radius, equal in length to the radius of the helix, draw the circle d^-dj-d,,- • — c?^^. The circumference of this circle will be the horizontal projection of the helix, since the generating point retains a constant radial distance from the axis.
Let D (df, d') represent the position of the generating point when in H, Beginning with d, divide the circumference of the circle into any number, say eight, equal parts. The points of division are c?,, cZ,,, (?,,p •••, dj^. Lay off upon a'-h', downward from G-L^ a distance a'-e' equal to the pitch of the helix. Divide this distance a'-e' into the same number of equal parts as the circumference of the circle has been divided into, and through the points of division, 1, 2, 3, 4, • • •, e\ draw horizontal straight lines.
While the generating point is making one circuit of the axis it moves through a vertical distance equal to a'—e'. Therefore, since the two motions are uniform, while the generating point is making any fractional part of the circuit it must move through the same fractional part of the total vertical distance.
When the generating point has made one eighth of its circuit its horizontal projection will be at d,,. Its vertical projection must be on a straight line through d,, perpendicular to G-L^ and on a straight line through 1 parallel to G-L^ and therefore at d".
If we draw vertical lines through c?,,^ c?,,,,, • • •, c?^^' ^^^^ ^ote their intersections with the corresponding horizontal lines, we shall obtain the points d'", d"'\ •••, t?^-^, other points in the vertical projection of the helix.
215. To assume a Point upon the Helix. See Fig. 86. Assume the horizontal projection of the point anywhere upon the horizontal projection of the helix, and through this point draw a straight line perpendicular to G-L to intersect the vertical projection of the helix in the required vertical projection of tlie point.
on the Curve.
Analysis. Since the generating point of a helix retains a constant distance from the axis, the curve may be traced upon the surface of a right circular cylinder whose axis is the axis of the helix.
Assuming the axis of the cylinder perpendicular to //, the portion of the base a^-b^-c^-d^-e^-f^j represents the horizontal projection of the portion of the helix in question.
Let a, represent the point in which the helix pierces H. Let B represent the point consecutive to a, (greatly magnified in its distance from a,), and let h^ represent the horizontal projection of B. Let C represent the point consecutive to B and let c^^ represent the horizontal projection of C
horizontal projections.
Connect a^ and ^ by a straight line ; also connect a^ and h^ by a straight line. These two lines together with the horizontal projecting line of B form a right-angled triangle in which a^-hj is the horizontal projection of a-B.
Practically speaking, the two lines a-B and aj-h, are identical with the arcs of which they are chords. For this reason the angle B-a,-hj measures the slope of the helix, that is, the constant inclination of the curve to H^ or the angle which a rectilinear tangent to the helix at any point makes with H,
Connect B and C by a straight line ; also connect h, and c^^ by a straight line. These two lines together with the two projecting lines B-hf and C-Cj^ form a quadrilateral in which B-C will make the same angle with H as that made by a^-B^ since the uniform motions of the generatinp- point give to each elementary portion of the helix the same inclination to H.
If the plane of the triangle a-B-hj be revolved about B-hj as an axis until it coincides with the plane of the quadrilateral B-c^,^ the line a-h^ will take the position a^^-h^^ which is a continuation of Cj-hj\ and the line a-B will take the position a^-B^ which is a continuation of C-B,
If the plane of the triangle a^-C-c^^ be revolved about C-c^^ as an axis until it coincides with the plane of the quadrilateral C-c?,,, the line a^-h^-c^, will take the position a^^-h^-c^^^ which is a continuation of d^-G^^ ; and the line a^-B-C will take the position a„-C, which is a continuation of D-C.
The line a^^-B is tangent to the helix at the point B, since it contains B and its consecutive point C. The line (i,-hf is the horizontal projection of this tangent and is itself tangent to the horizontal projection of the helix at the points,. The tangent a^^-B pierces H a.t a,^^ at a distance from 5,- equal to the rectification of the arc a-h^.
Again, a^^-C is tangent to the helix at the point C, since it contains C and its consecutive point D. The line a^j-hj-Cj^ is the horizontal projection of this tangent and is itself tangent to the
That portion of the tangent a,-B between the points a,, and B is the rectified length of the curve a-B, and that portion of the tangent a^^-C between the points a,^, and C is the rectified length of the curve a^-B-C.
We have now considered three consecutive points, a„ B, and C\ of the helix, and it will be evident that the same process of reasoning may be applied indefinitely to the consecutive points of the curve.
We may conclude, then, that the horizontal projection of a rectilinear tangent to a helix at any point on the curve, provided the axis of the helix is perpendicular to If^ will be tangent to the horizontal projection of the helix at the horizontal projection of thepoint of tangency ; also that the tangent itself will pierce H upon the horizontal projection of the tangent and at a distance from the horizontal projection of the point of tangency equal to the rectification of that portion of the horizontal projection of the helix between the point in which the helix pierces H and the horizontal projection of the point of tangency.
By use of these principles we can draw the two projections of a rectilinear tangent to the helix when the axis of the helix is assumed perpendicular to //.
Construction. Let the helix be represented as in Fig. 88. Assume any point, as E, upon the curve (see Section 215). At e, draw e^-f^ tangent to the horizontal projection of the helix. Upon this tangent lay off from e, a distance e^-ff equal to the rectification of the arc e-d^, where d^ is the point in which the helix pierces H, and where e, is the horizontal projection of the point of tangency. The line e-f, is the horizontal projection of the required tangent, and /, is the point in which this tangent pierces H. The vertical
of the required tangent.
By this process the position of the vertical projection of the tangent to the helix is determined by two points, e' and /', and the unsatisfactory task of drawing a rectilinear tangent to an irregular curve is avoided.
whose radius is 4 and pitch 10 intersects a horizontal plane 4 above H,
219. Problem 146. Fiyid the point in which the right-handed helix whose radius is 4 and pitch 9 intersects a plane containing the axis and making an angle of 45 degrees with V,
220. Generation of Surfaces. We may regard a surface as the generation resulting from the movement of a line which in the course of the generation occupies an infinite number of consecutive positions at infinitely small distances apart. The moving line is called the generatrix^ and the various positions which it occupies during the generation are called elements of the surface.
The portion of the surface generated by the line while moving from one position to its consecutive position is called an elementary surface^ and while in theory the distance between the two consecutive elements must be taken into account, practically speaking the two elements may be regarded as one and the same.
221. Classification of Surfaces. The character of the surface generated will depend both upon the character of the generatrix and upon the nature of its motion.
Depending upon the character of the generatrix we have two classes of surfaces: first, those which are generated by straight lines, or those which have rectilinear elements ; and second, those which are generated by curved lines, known as surfaces of double curvature.
Depending upon the nature of the motion of a rectilinear generatrix w^e have (1) the plane which may be generated by one straight line moving in such a way as to touch another straight line and always remaining parallel to its first position ; (2) the single curved surface which may be generated by a straight line moving in such a way that any two of its consecutive positions shall be in the same plane ; and (3) the warped surface which may be generated by a straight line moving in such a way that no two of its consecutive positions shall be in the same plane.
cylhidrical surface.
When the rectilinear generatrix moves in such a way that all its positions pass through a common point and no three of its consecutive positions lie in the same plane, the surface is a conical surface.
When the rectilinear generatrix moves in such a way that consecutive positions intersect two and two and at the same time in such a way that no three consecutive positions lie in the same plane, the surface is a convolute.
curved surface.
If the generatrix is a straight line and does not lie in the same plane with the axis, the surface is a warped surface of revolution^ since from the nature of the generation consecutive elements of the surface cannot lie in the same plane.
If the generatrix is a curved line, as it will be in all cases save those mentioned above, the surface will be one of double curvature, or a double curved surface of revolution.
224. Double Curved Surfaces of Revolution. If the generatrix of a double curved surface of revolution is the circumference of a circle and the axis is a diameter of the circle, the surface generated is that of a sphere.
If the generatrix is the curve of an ellipse and the axis is one of the axes of the ellipse, the surface generated is that of the ellipsoid of revolution. The ellipsoid of revolution is called a prolate or an ohlate spheroid according as the long or the short axis is used.
hyperholoid of revolution.
225. Representation of Surfaces. Surfaces which exist within definite limitations are usually represented by projecting upon H and V the limiting lines as seen from the two principal standpoints of projection. Other surfaces are too irregular in their formation to be represented in this way, and all that is attempted is to represent by projection a sufficient number of the elements of the surface to reveal tlie character of some small portion of the surface under consideration.
that point.
A plane is tangent to a surface at a given point when it contains all the rectilinear tangents to the surface at that point. In other words, if a plane is tangent to a surface, and any cutting plane be passed through the point of tangency, the cutting plane will cut from the surface a line, and from the tangent plane a straight line, tangent to the first line at the point of tangency.
determine their plane.
If the surface has rectilinear elements, the tangent plane must contain the rectilinear element passing through the point of tangency, since the rectilinear tangent Xo a rectilinear element is the element itself. This element is the element of tangency.
If the surface is of single curvature, we may say that a plane is tangent to the surface at a given point when it represents the plane in which the generatrix is moving at the instant in which it passes through the point of tangency.
For this reason we may say that a plane is tangent to a single curved surface at a given point when it contains both the element through the point of tangency and its consecutive one. If through the element containing the point of tangency we pass a secant plane, it will cut the surface in two distinct lines, one of which is the element through the point of tangency and the other another
CLASSIFICATION OF SUEFACES 87
line somewhat removed from the first. If this secant plane be revolved about the element of tangency as an axis toward the position of the tangent plane, the element of tangency will remain stationary and the second line will gradually approach the position of the first ; and when the second line takes the position consecutive to the element of tangency, or practically the position of the element of tangency itself, the secant plane will take the position of the tangent plane.
If a plane is tangent to a single curved surface at a given point, it will be tangent to the surface all along the rectilinear element containing the point of tangency. For if through any point of this element a cutting plane be passed oblique to the elements, it will cut from the consecutive element (which is also a line of the tangent plane) a point consecutive to the assumed point.
These two consecutive points lie in the tangent plane and at the same time lie on the line cut from the surface by the oblique plane. A straight line through these two points is tangent to the line cut from the surface at the assumed point, and lies in the tangent plane. The tangent plane is then tangent to the surface at this point, since it contains two rectilinear tangents to the surface at this point.
If then a plane is tangent to a single . curved surface, any plane passed oblique to the element of tangency will cut from the tangent plane a straight line wliich will be tangent to the line cut from the surface at the point where the element of tangency intersects the oblique plane.
Two surfaces are tangent to each other when they are both tangent to the same surface at a common point, or when planes passed through their point of contact cut from the two surfaces lines which are tangent to each other at the point of contact.
227. Normals to Surfaces. A straight line is normal to a surface at a given point when it is perpendicular to the plane which is tangent to the surface at that point.
when laid out on a plane.
Just as a curved line is rectified by rolling the curve out on a rectilinear tangent to the curve, so a surface is developed by rolling the surface out on a plane tangent to the surface.
In cases of prisms and pyramids, or of any surfaces made up of plane faces, the plane of one of the faces is taken as the plane of development, and the successive faces are brought into coincidence with the plane of development by revolving them one after another about the edges as axes.
In cases of cylinders and cones, or other surfaces of single curvature, a plane tangent to the surface along some element is taken as the plane of development, and the surface is tlien rolled out element after element, peeling off, as it were, the outer coating of the surface and spreading it out on the plane.
The development of a surface may be used as a templet, or pattern, for cutting out a plane surface form, which by a process converse to that employed in development may be made to take the shape of the original surface.
230. Shade Lines. Objects in nature, as a rule, are exposed to some source of light so that some portions of their surface are in the light and other portions are in the dark.
The sun is usually taken as the source of light, and on account of its great distance from the earth we may safely consider such solar rays as fall upon terrestrial objects of finite dimensions as parallel.
The source of light is conventionally assumed in such a position that the rays shall be parallel to that diagonal of a cube (the cube resting on H in the first quadrant with one face coincident with V) which slopes downward to the right toward V.
When the position of the object is definitely known it will be easy to determine which portions of the surface are in the light and which portions' are in the dark.
Those lines on a surface which separate light portions from dark portions are called shade lines, and in the drawing, for purposes of clearness, are represented a little heavier than the ordinary line.
In Fig. 89, remembering the direction taken by rays of light, it is evident that the upper, the left-hand, and the front faces of the cube are in the light and that all the others are in the dark.
represented by a heavy broken line.
When two lines of the surface, one a shade line and the other an ordinary line, are projected upon the same line, it is customary to give preference to that line which is visible. For example, in Fig. 89 the lines A-E and F-L have a common horizontal projection ttf-e^, but the line A-E is the visible line, and inasmuch as it is not a shade line the projection a-e, is made light.
REPRESENTATION OF SINGLE CURVED SURFACES
231. Cylindrical Surfaces and the Cylinder. The cylindrical surface is a single curved surface which may be generated by a moving straight line which during the movement touches a given curved line and always remains parallel to its first position (see Section 222).
The generating line is called the generatrix^ the curved line is called the directrix^ and the various positions occupied by the generatrix are called the rectilinear elements of the surface.
The intersection of a cylindrical surface by any plane which is not parallel to the elements is called a section^ or base, of the surface. When this plane is taken perpendicular to the elements, the section is called a right section^ and according to the nature of this section cylindrical surfaces are classified as circular^ elliptical, parabolic, hyperbolic, etc.
often serve as a convenient base.
A plane parallel to the elements of a cylindrical surface and cutting the surface will cut the surface in elements, since all the elements of such surfaces are parallel.
the elements of the surface is called the axis of the cylinder.
If one of two parallel straight lines is revolved about the other as an axis, the surface so generated is cylindrical, and the cylinder so generated is a cylinder of revolution whose right section is a circle.
anywhere but which must not be regarded as limiting the surface, and by projecting its extreme elements, that is, those elements which from the observer's position appear to limit the surface.
dicular to V and whose bases are right sections. See Fig. 100.
Case 3. To represent the cylinder tvhen its base is on H. See Fig. 101. Let the circle whose center is a^ represent the base on H^ and let A-B represent the axis. Tangent to the circular base and parallel to a-b^ draw the straight lines d,-e, and f^-g,. These lines represent the horizontal projections of the extreme or limiting elements, as seen from the observer's standpoint while projecting on i/, since no elements can occupy positions at greater distance from the horizontal projecting plane of A-B. The vertical projections of I) and F are d' and/' respectively. Through d' and /' and parallel to a'-b' draw the straight lines d'-e' and f-g\ to represent the vertical projections of these elements.
a!—V draw the straight lines k^-V and These lines represent the vertical projections of the extreme or limiting elements, as seen from the observer's standpoint while projecting on F, since no elements can occupy positions at greater distance from the vertical projecting plane of A-B. Through k^ and m^ and parallel to a-b^ draw the straight lines k^-l^ and m-n^^ to represent the horizontal projections of these elements.
It will be evident that if the dimensions or position of the cylinder be changed, the projections of the cylinder will also be changed. It will also be evident that a cylinder of definite dimension and position will have
cylinder when the plane of its
base is oblique to H but perpendicular to V. In Fig. 102 the circle whose center is a, represents the horizontal projection of the base ; the straight line k'-m'
included between the two vertical lines k,-k' and m—m\ each drawn tangent to the circle whose center is a,, represents the vertical projection of the base, and A-B represents the axis.
in the previous case. The lines k'-V and m'-n' represent the vertical projections of the highest and lowest, and therefore the extreme, elements as seen from the observer's standpoint while projecting on V.
233. To assume a Rectilinear Element of the Cylinder. Let the cylinder be represented with a circular base on H^ as shown in Fig. 103. Assume any point, as E^ in the circumference of the
the cylinder be represented as in Fig. 103. Assume at random the
horizontal projection o, of the point. Draw o-d,-ef parallel to a^-bf, to represent the horizontal projection of the element con-
ment pierces // either at d, or at e^ according as 0 is assumed on the upper or on the lower surface of the cylinder. Assuming the point on the lower surface of the cylinder, the element in question will be vertically projected at e'-o\ and the point 0 must be
235. Problem 147. G-iven a cylinder whose axis is oblique to H and V and whose base is a circle in V; required to draw the two projections of the cylinder and to assume a point upon the surface.
236. Problem 148. Given a cylinder whose right section is a circle and whose axis is in such a position that its horizontal projection is inclined 30 degrees to G-L and its vertical projection is inclined 60 degrees to G-L; required to draw the two projections of the cylinder and to assume a point upon the surface.
237. Problem 149. Given a cylinder whose right section is a circle and whose axis is parallel to G-L; required to draw the two projections of the cylinder and to assume a point upon the surface.
238. Problem 150. Given a cylinder whose base is a circle on If and whose axis is in a profile plane and oblique to H ; required to draw the two projections of the cylinder and to assume a point upon the surface.
239. Conical Surfaces and the Cone. The conical surface is a single curved surface which may be generated by a moving straight line which during the movement touches a given curved line and constantly passes through a given fixed point (see Section 222).
The generating line is called the generatrix^ the curved line is called the directrix, the fixed point is called the vertex, and the various positions occupied by the generatrix are called rectilinear elements of the surface.
It is evident from the nature of the generation of the conical surface that there will be generated simultaneously, on opposite sides of the vertex, two equivalent portions of the surface. These portions of the surface are called nappes of the* surface.
drical.
The intersection of a conical surface by any plane not containing the vertex is called a section, or base, of the surface. When this plane is taken perpendicular to the axis* the section is called a right section, and conical surfaces are classified according to the nature of this section as circular, elliptical, parabolic, hyperbolic, etc.
A plane containing the Vertex of a conical surface and intersecting the surface will cut the surface in elements, since all the elements of such surfaces pass through the vertex.
If the base of a conical surface is a closed *'^ curve, like a circle or an ellipse, the space inclosed by the conical surface is called a ^. cone, and the straight line connecting the center of the base with the vertex is called the axis of the cone.
240. To represent the Cone. A cone is usually represented by projecting the vertex, a base, and the extreme or limiting elements.
Case 1. To represent a circular cone whose axis is perpendicular to H and whose base is a right section. See Fig. 104, in which A-B represents the axis of the cone and in which F-D-G-E represents the circular base.
Through the point 6, and tangent to the circle whose center is a, draw b-d, and b-e^. These lines represent the horizontal projections of the extreme or limiting elements as seen from the observer's standpoint while projecting on H^ since no elements can occupy positions at greater distance from the horizontal projecting plane of A-B. The vertical projections of D and E are d' and e' respectively, and the lines b'-d' and b'-e' are the vertical projections of these elements, ^i^- 1^^ Tangent to the circular base and perpen-
dicular to G-L dr^wf-f and g-g'. Connect/' and b\ also connect g' and b', by straight lines. These lines represent the vertical projections of the extreme or limiting elements as seen from the observer's standpoint while
It will be evident that if the dimensions or position of the cone be changed, the projections of the cone will also be changed. It will also be evident that a cone of definite dimension and position will have definite projections fully determining the cone.
SINGLE CURVED SUEFACES
It must be remembered that in assuming the circular base and the vertex, both at random, we have represented a cone at random and not one of definite dimension and position.
Case 4. To represent the cone
tvJien the plane of its base is oblique to H but perpendicular to V. See Fig. 107. The circle whose center is a, g^ represents the horizontal projection of the base, and the straight line f'-g' included between the two vertical lines/,-/' and g-g', each drawn tangent to the circle whose center is ap represents the vertical projection of the base. B represents the vertex and A-B represents the axis.
The lines b'-f and b'-g^ represent the vertical projections of the highest and the lowest elements, and therefore the extreme elements, as seen from the observer's standpoint while projecting on V.
projection o, of the point at random. Draw bf-0f-d,-e, to represent the horizontal projection of the element containing the point 0. This element pierces H either
under surface of the cone.
Assuming the point on the upper surface of the cone, the element in question will be vertically projected at b'-d', and the point 0 must be vertically projected at o' on the straight line through 0, perpendicular to G-L.
243. Shade Lines. Shade lines upon cylindrical and conical surfaces, since such lines are purely imaginary elements of the surface, unless they occur at the intersection of base and surface, are best not represented by heavy lines.
When the plane of the base of a cylinder or cone is perpendicular to the plane of projection, the projection of the base upon this plane of projection is a straight line, and as a rule will represent a line in space, which is partially a shade line and partially not.
For the sake of appearance the projection of the base under these conditions will be drawn either wholly a heavy line or wholly a light line according as the portion which should be represented as a shade line exceeds or does not exceed in length that portion which should be represented as a light line.
In Fig. 99, remembering the direction taken by the rays of light, it is evident that the upper base of the cylinder and that portion of the surface to the left and limited by the two elements D-E and F-G will be in the light, and that the remainder of the surface will be in the dark. Therefore the only shade lines to be represented in this case are D-M-F and E-L-G.
When projecting oniT, D-M-F is visible and its horizontal projection d-m-f, is drawn as a heavy line. When projecting on Fthe portion M-F of the shade line D-ilf-i'' and the portion L-G of the shade line E-L-G are visible. Since, then, only the small portion w!-f of the vertical projection of the upper base should be represented as a heavy line, the whole line is made a light line. Since the larger portion V -g^ of the vertical projection of the lower base should be represented as a heavy line, the whole line is made a heavy line.
In Fig. 104 the shade line to be represented is approximately D-F-E. Since the larger portion f'-e' of the vertical projection of the base should be made a heavy line, the whole line f'-g' is made a heavy line.
244. Problem 151. Given a cone whose axis is oblique to If and V and whose base is a circle on V; required to draw the two projections of the cone and to assume a point upon the surface.
245. Problem 152. Given a cone whose axis is perpendicular to H, whose vertex is 1 unit below If, and whose right section at the distance of 8 units below If is a circle 6 units in diameter; required to draw the two projections of the cone and to assume a point upon the surface.
246. Problem 153. Given a cone whose base is a circle on If and whose axis is in a profile plane and oblique to If; required to draw the two projections of the cone and to assume a point upon the surface.
247. The Convolute. The convolute is a single curved surface which may be generated by a straight line moving tangentially to a curve of double curvature. The generating line is called the generatrix, the curved line is called the directrix, and the various positions occupied by the generatrix are called the rectilinear elements of the surface.
Since a rectilinear tangent to a curved line contains two consecutive points of the curve, two consecutive tangents must have a point in common and therefore intersect. The consecutive elements of the convolute, then, will intersect, and since the directrix is of double curvature, only those elements which are consecutive will, in general, intersect.
convolute.
248. To represent the Helical Convolute. The helical convolute is represented in Fig. 87, where for purposes of clearness the distances between consecutive positions of the generatrix are greatly magnified.
The curve a -^-C-i>-^-7^ represents the helical directrix. The straight lines a^-B-C, a^^-C-D, aj^^^-D-E, etc., represent positions of the generatrix or rectilinear elements of the surface.
It will be noticed here, as stated above, that only consecutive elements intersect; for example, a^^-C-D intersec^ts its preceding consecutive element, a^-B-C, at C; it also intersects its succeeding consecutive element, a^^^-B-E, at B ; but it does not intersect the element ay-E-F, which is not consecutive to it.
If we conceive a large number of these tangents or elements of the surface to be drawn at small distances apart, we may form an idea of the character of the surface.
The curved line a,-a,,-a,, -a,,,,-, etc., traced through the various points in which the elements pierce H^ is the intersection of the surface with H and may be taken as the base of the surface.
From the method by which these points <x„, a,,,, a,,,,, etc., are found (see Section 216), it will be seen that the base of the helical convolute, in case the axis of the helical directrix is taken perpendicular to H^ is the involute of that circle which represents the horizontal projection of the directrix.
the helical directrix and the base on H is considered.
Since the generatrix extends without limit in both directions from the point of tangency on the helix, there will be generated simultaneously on opposite sides of the helical directrix two distinct portions of the surface. These two portions of the surface are called nappes of the surface, and their line of separation, which is the helical directrix, is called the edge of regression.
From the nature of the helical directrix and the relation of the generatrix to the directrix it is evident that if the generation be extended beyond one circuit of the axis, the surface will consist of a series of overlapping surfaces whose base or intersection with H will have the form of a spiral.
251. The warped surfac3 may be generated by a straight line moving in such a way that its consecutive positions do not remain in the same plane. Evidently there can be as many warped surfaces as there are distinct laws restricting the motion of straight lines in this way.
252. The Warped Surface with Two Linear Directrices and a Plane Directer. The warped surface with two linear directrices and a plane directer is generated by the movement of a straight line which constantly touches
under consideration.
254. To assume a Rectilinear Element of the Hyperbolic Paraboloid. See Fig. 109. Let M-JSf smd 0-P represent the rectilinear directrices, and let *S^ represent the plane directer.
Assume any point, as A^ upon the directrix M-N^ and through A^ by Section 172, draw the plane T parallel to .S'. By Section 151 find the point B in which the directrix 0-P intersects S, and
connect A and ^ by a straight line. A-B is an element of the surface, since it touches the two directrices and lies in the plane T which is parallel to the plane directer.
By Section 254 assume a number of rectilinear elements of the surface in the vicinity of X. These elements are A-B^ D-E^ F-G, K-L^ etc. These elements, beginning with A-B^ intersect the plane *S' in the points Y, W, B, Q, etc. The line Y-W-B-Q is the intersection of S and the warped surface, and must contain X.
256. The Warped Surface with two Curvilinear Directrices and a Plane Directer. The warped surface with two curvilinear directrices and a plane directer is generated by a moving straight line which always touches two curvilinear directrices and remains parallel to a plane directer.
surface at G; and so on. L-K-G-F is the intersection of the plane through the point A with the horizontal projecting surface of 0-P, The point X, in which 0-P crosses L-K-G-F, is the point in which 0-P intersects the plane through the point A, The straight line A-X is the required element, since it is in a plane parallel to S and touches the two directrices M-N and 0-P,
the plane directer, the surface is called a right conoid. ,
260. Problem 154. Assume a rectilinear element upon the warped surface whose rectilinear directrices are [^4 = — 6, 3, 1 ; B = 1, 6, 6] and [C = 4, —2, 1; i> = 4, —2, 6] and whose plane directer is ^ = 4, 30°, 20°.
261. Problem 155. Assume a rectilinear element upon the warped surface whose rectilinear directrices are [^ = — 4, — 4, 2 ; ^ = — 4, 4, 6] and [6' = 0, 1, 6 ; D = 6, 6, 1] and whose plane directer is ^=6, 30°, 60°.
262. Problem 156. Assume a rectilinear element upon the warped surface whose rectilinear directrices aj-e [A = — 6, — 3, 4 ; B = 6, — 3, 4] and [C = — 2, — 5, 6 ; i> = 4, 1, 2] and whose plane directer is S = 0, 30°, 60°.
263. Problem 157. Given a warped surface with two curvilinear directrices and a plane directer^ the latter coincident with V; required to draw a rectilinear element of the surface.
264. Problem 158. Given a warped surface with two curvilinear directrices and a plane directer, the latter parallel to G-L hut oblique to H and V; required to draw a rectilinear element of the surface.
265. Problem 159. Given a warped surface with one rectilinear directrix and one curvilinear directrix and a plane directer; required to draw a rectilinear element of the surface.
directrix is perpendicular to II and the plane directer is H.
267. The Warped Surface with Three Linear Directrices. The warped surface with three linear directrices is generated by a straight line moving in such a way as to touch the three directrices.
nappe is a warped surface with three rectilinear directrices.
This surface is represented by locating the three rectilinear directrices and a sufficient number of the rectilinear elements, or positions occupied by the generatrix, to reveal the character of that portion of the surface under consideration.
Connect A and 6^ by a straight line which intersects 0-P at JT, since A-G and 0-P are in the same plane. A-K-G is an element of the surface, since it touches the three directrices.
270. To assume a Point upon the Surface of the Hyperboloid of One Nappe. First assume an element of the surface and then assume a point upon the element, or follow the directions of Section 255.
Assume a point A on one of the directrices M-N. Assume a number of points, 1, 2, 3, 4, etc., on one of the other directrices 0-F. Through A and 1, A and 2, A and 3, etc., draw the straight lines A-l-B, A-2-D, A-^-A\ A-4i-F, etc. These lines are elements of a conical surface with vertex at A.
272. Problem 161. Assume a rectilinear element upon the hyperholoid of one nappe whose three directrices are [^ = — 6, 6, 2 ; B=-l, -1, 6], [C = -2, -2, 1; D-2, 5, ^, and [^=0, 6, 1; F=^, 3, 6].
273. Problem 162. Assume a rectilinear element upon the hyperhaloid of one nappe whose three directrices are [^ = — 6, — 2, G ;' ^ = - 1, 5, 2], [(7 = 0, 2, 2 ; i> = 0, 2, 6], and [^ = 2, - 2, 1 ; i^-6, 4, 6].
274. Problem 163. G-iven a warped surface with three curvilinear directrices^ one in //, another in F, and the third in the third quadrant; required to assume a rectilinear element of the surface.
275. The Helicoid. The helicoid is a warped surface generated by a straight line moving uniformly around and along a rectilinear directrix which it intersects and with which it makes a constant angle.
276. To represent the Helicoid. The helicoid is represented by locating the directrix or axis (which is usually taken perpendicular to H)^ a number of the more important rectilinear elements of the surface, and the base or intersection of the surface with H.
To do this we must know the angle which the generatrix makes with the directrix, and the vertical distance through which the generatrix moves for each circuit of the directrix.
In Fig. 114 let A-B represent the directrix, or axis, assumed perpendicular to H. Through any point C (<?,, c^) on the axis draw C-D parallel to V and making the given angle with the axis. Since C-D is taken parallel to V its horizontal projection c^-d, will be parallel to G-L^ and its vertical projection c'-d' will make the same angle with a'-V that the generatrix makes with the directrix.
Since the generatrix moves uniformly around and along the directrix, each point of the generatrix will generate a helix whose pitch will be equal to the total rise or fall of the generatrix per revolution, and whose radius will be equal to the distance of the point from the directrix.
Lay off upon a'-h' downward from c' the distance c '-(?'' equal to the total fall of the generatrix per revolution, and through e^ draw c^-d}^ parallel to c'-d' . The line c^'-d^' is the vertical projection of the generatrix at the end of one circuit.
horizontal projection is the circle d-djj-djjj—djj,f- • • • , and whose vertical projection d!-d"-d"^-d""-d^ may be found by Section 214.
of the point D takes the position c?,,, or when the horizontal projection of the generatrix takes the position c-dff, the vertical projection, d", of D in this position will fall upon the vertical projection of the helix generated by I) and on the straight line through d^^ perpendicular to G-L,
This shows that in moving from
the first position to this position all points of the generatrix have moved downward a distance equal to the distance of d" below G-L. Therefore, to obtain the vertical projection of C for this position of the directrix, lay off upon a'-h' downward from c' a distance c'-c" equal to the distance of d" below G-L. The point c" is the vertical projection sought, and the straight line e"-d" is the vertical projection of the generatrix in this position. In the same way we may find the horizontal and vertical projections of the generatrix in other positions, as may be seen from the diagram.
The generatrix in its first position pierces j^ at c?,, in the second position it pierces II at e^^ in the third position it pierces H at /,, etc. Since these various positions of the generatrix represent elements of the surface, the curve dj-e-f-g^- • • • will represent the base of the surface.
If the angle between the generatrix and the directrix is a right angle, the surface becomes a right conoid. The generatrix is a straight line and moves in such a way as to touch two directrices, one rectilinear and the other curvilinear, and remains parallel to a plane directer H^ to which the rectilinear directrix is perpendicular.
In Fig. 115 let A-B represent the axis of a helicoid, and let D-A and D-E represent two generating elements of the surface, equally inclined to the axis, parallel to F, and intersecting at D.
While the generating lines D-A and D-E generate their respective helicoidal surfaces, the three points F, D, and G will generate their respective helices, and the straight line F-K will generate a cylindrical surface whose diameter is equal to l,-fr
If in this particular case the pitch of the helicoids is made equal to the distance F-G^ or some multiple of it, the surface generated by the two sides D-F and D-G of the isosceles triangle D-F-G will be the surface of a triangular-threaded screw.
After a half revolution the two generating lines will take the positions indicated in vertical projection by d"-a" and d"-e" respectively, and after a complete revolution they will take the positions indicated in vertical projection by d'"-a"' and d"'-e"' respectively. We may regard the thread of a triangular-threaded screw as generated by the surface of an isosceles triangle which moves uniformly around and along the surface of a right circular cylinder in such a way that the base of the triangle always rests on the surface of the cylinder, and the plane of the triangle always contains
of the triangle per revolution
is equal to its base, the screw is called single threaded ; if equal to twice the base of the triangle, it is called double threaded;
The helices generated by the points F, D, and G may be represented by Section 214, remembering that the pitch in each case is equal to the length of the base of the triangle.
In Fig. 116 let A-B represent the axis of a helicoid, and let D-E and F-G^ equal in length, perpendicular to the axis, parallel to F, and at a stated distance apart, represent two generating ele-
If in this particular case the
pitch of the helicoidal surfaces is made equal to twice, or four times, or six times, etc., the distance D-F^ the surface generated by the three sides K-D, D-F^ and F-L of the square K-D-F-L will be the surface of a square-threaded screw.
In Fig. 116 the pitch is made equal to four times the distance D-F. After a half revolution the three generating lines D-K^ D-F^ and F-L will take the positions indicated in vertical projection by d"-k'', d''-f\ and f'-l" ; and after a complete revolution they will take the positions indicated in vertical projection by d''^-k"'^ d'"-r\ and f"'-l"'.
along the surface of a right circular cylinder in such a way that one side of the square always remains on the surface of the cylinder and the plane of the square always contains the axis of the cylinder.
If the downward movement of the generating square per revolution is equal to twice the side of the square, the thread is called single threaded, if equal to four times the side of the square it is called double threaded, and if equal to six times tlie side of the square it is called triple threaded.
Fig. 116 represents a double-square-threaded screw. The inner cylinder is represented in plan by k-Oj-k,-p, and in elevation by k' -n' -r' -q' . The generating square in its original position, when its plane is parallel to T, is represented in plan by k-d, and in elevation by k'-d'-f'-V.
The helices generated by the four vertices K, i>, 7'', and L of the square may be represented by Section 214, remembering that the pitch of each helix is equal to four times the side of the generating square.
The thread directly below the one just generated is generated by the square Z- W-X- Y, which moves below the square K-D-F-L and at a distance equal to the side of the square.
REPRESENTATION OF SURFACES OF REVOLUTION
284. General Properties of Surf aces of Revolution. The intersection of a surface of revolution by a plane perpendicular to the axis is the circumference of a circle, since from the nature of the generation of such surfaces (see Section 223) each point of the generatrix generates the circumference of a circle whose plane is perpendicular to the axis.
If two surfaces of revolution have a common axis, and the surfaces either intersect or are tangent to each other, their line of intersection or of tangency will be the circumference of a circle whose center is in the common axis and whose plane is perpendicular to the axis. For if through the axis and any point of the line of intersection or of tangency we pass a plane, it will cut from the two surfaces two lines which will either intersect or be tangent at the assumed point. If now these two lines with their point of intersection or of tangency be revolved about the common axis, the lines will generate their respective surfaces, and the point of intersection or of tangency, which will remain common to the two surfaces, and therefore generate their line of intersection or of tangency, will generate the circumference of a circle whose center is in the axis and whose plane is perpendicular to the axis.
Two surfaces of revolution are tangent to each other when they are tangent to the same surface at a common point, or when planes passed through their point of contact cut from the two surfaces lines which are tangent to each other at the point of contact.
A plane tangent to a single curved surface of revolution at a given point will be tangent to the surface all along the rectilinear element passing through this point (see Section 226).
285. The Meridian Plane and the Meridian Line. Any plane containing the axis of a surface of revolution is called a meridian plane and its intersection with the surface is called a meridian line.
All meridian lines of the same surface of revolution are the same. If a plane is tangent to a surface of revolution at a given point, it will be perpendicular to the meridian plane of the surface passing through this point. For if through the point of tangency we pass a plane perpendicular to the axis, it will cut from the surface the circumference of a circle, from the tangent plane a straight line tangent to the circle at the point of tangency, and from the meridian plane a straight line which is the radius of the circle at the point of tangency, and therefore perpendicular to the rectilinear tangent. Through the point of tangency and parallel to the axis draw a straight line. This line is in the meridian plane, is perpendicular to the plane passed perpendicular to the axis, and is therefore perpendicular to the rectilinear tangent.
to the meridian plane.
286. Representation of Surfaces of Revolution. Surfaces of revolution are usually represented by -jr^ assuming their axes perpendicular to H^ although this is not necessary. The intersection of the surface with H^ or the horizontal projection of some important section of the surface made by a plane perpendicular to the axis, is taken for the horizontal projection of the surface, and the vertical projection of the meridian curve whose plane is parallel to V is taken as the vertical projection of the surface. 287. To assume a Point upon any Surface of Revolution. Analysis and Construction. Let the surface of revolution be represented as in Fig. 117, where A-B represents the axis, where the circle e-f^ represents the horizontal projection of the largest horizontal circle of the surface, and where d'-e'-f'-g' represents
Assume at random the horizontal projection p^ of the required point. The horizontal projecting line of the point must intersect the given surface in all the points of the surface which can have their horizontal projection at p^ . Through this horizontal projecting line and the axis of the surface pass the meridian plane S, which will cut from the surface a meridian curve. The points in which this meridian curve is intersected by the horizontal projecting line of the point must be the points in question.
Revolve the plane >S^ about A-B as an axis until the plane is parallel to F. The horizontal trace will then take the position ^S-s,,, the point p, will take the position jo,,, and the vertical projection of the horizontal projecting line will take the position p""-p^-p^^. The plane of the meridian curve is now parallel to V and the vertical projection of the meridian curve will be identical with the vertical projection of the surface.
The points p"'\ p^^ p^\ the points in which the vertical projection of the horizontal projecting line in revolved position intersects the vertical projection of the meridian curve in revolved position, must represent the vertical projections of the required points in revolved position.
After the counter revolution p,j will take the position jt?,, p"^' will take the position p'^ p^ will take the position p'\ and p^^ will take the position Jt?"^ Therefore any one of the three points p\ p", or p'" may be taken as the vertical projection of the point upon the surface which has its horizontal projection at p^ .
surface.
293. Problem 174. Given a sphere whose center is in the second quadrant and equidistant from H ajid V; required to represent the sphere and to assume a point upon the siirface.
sume a point upon the surface.
297. The Hyperboloid of Revolution of One Nappe. The hyperboloid of revolution of one nappe is a warped surface of revolution generated by the revolution of a straight line about a rectilinear axis not in the plane of the generatrix.
To represent the hyperboloid of revolution of one nappe we must know the relation of the generatrix to the axis. This may be expressed by giving the distance of the generatrix from the axis and the inclination of the generatrix to a plane perpendicular to the axis. The distance of the generatrix from the axis will, of course, be measured on a straight line perpendicular to the two (see Section 199).
rectilinear axis.
When the generatrix occupies a position parallel to F, the angle which its vertical projection makes with G-L must equal the angle which the generatrix makes with H -, and the perpendicular distance from the point in which the axis pierces H to the horizontal projection of the generatrix must equal the distance of the generatrix from the axis (see Problem 137, Analysis 2).
Therefore through any point, as e\ on the vertical projection of the axis draw d'-e^-f\ making w^ith G-L the angle which the generatrix is to make with H. Draw d-e-g, parallel to G-L and at
SURFAC ES OF REVOLUTION
a distance from the point in which the axis pierces H equal to the distance which the generatrix is to be from the axis. D-E-F represents the generatrix in a position parallel to V and between the axis and V.
From the nature of the generation every point of the generatrix will generate the circumference of a circle whose plane is perpendicular to the axis and whose radius is equal to the distance of the point from the axis.
generate circumferences of circles of gradually increasing radii.
It will be also observed that the circumference of the circle generated by a point of the generatrix at any given distance above the plane of the circle of the gorge will have the same radius as the circumference of the circle generated by a point of the generatrix at the same distance below the plane of the circle of the gorge.
the plane of the circle of the gorge.
The circumference of the circle d,-p-q,-r,, generated by the point 7), the point in which the generatrix D-E-F pierces H, is called the base of the surface.
If through E we draw another straight line G-E-K parallel to V and making the same angle with H as D-E-F^ and revolve this line about the axis A-B^ it will generate a surface identical with the one which we have been considering, since for any given distance above or below the plane of the circle of the gorge points upon the two generatrices are equidistant from the axis.
The surface can then be generated by the revolution of two distinct straight lines. Therefore through any point of the surface two rectilinear elements of the surface may be drawn.
Since every element of the surface intersects the circumference of the circle of the gorge, and since the circle of the gorge is the smallest circle of the surface, the horizontal projection of each element of the surface must contain a point in the horizontal projection of the circumference of the circle of the gorge and yet cannot intersect it. Therefore the horizontal projection of each element of the surface must be tangent to the horizontal projection of the circle of the gorge.
298. To assume a Rectilinear Element of the Hyperboloid of Revolution of One Nappe. See Fig. 118. Assume any point, as P, upon the base. Through p, draw p-o, tangent to the horizontal projection of the circle of the gorge. This is the horizontal projection of an element of the surface piercing // at P and crossing the circle of the gorge at 0. P is vertically projected at p' and 0 is vertically projected at o'. Therefore p'-o' is the vertical projection of the element in question.
299. To assume a Point upon the Surface of the Hyperboloid of Revolution of One Nappe. First assume an element of the surface and then assume a point upon the element.
Or we may assume the horizontal projection of the point at random, through it draw the horizontal projection of the element containing the point, thence the vertical projection of the same element as explained above, and finally the vertical projection of the point upon the vertical projection of the element.
300. To determine the Meridian Curve of the Hyperboloid of Revolution of One Nappe. We shall consider the section of the surface made by the meridian plane parallel to F, for the vertical projection of this curve will be equal in every respect to the curve
itself. In Fig. 118, S-s, is the horizontal trace of a meridian plane parallel to V. This plane intersects the circumference of the circle of the gorge at M and N. Therefore m' and n' are two points in the vertical projection of the required meridian curve.
For the same reason / and q' are two more points in the vertical projection of the curve, since B and Q are the two points in which this same meridian plane intersects the base of the surface.
To find other points of the curve, draw horizontal planes, for example T. This plane cuts the generatrix D-E-F at X (x^, x') and cuts the surface itself in the circumference of a circle whose horizontal projection is x-x^^-Xj, and whose vertical projection is x"-x^". This circumference intersects the meridian plane at X (Xff^ x"), also at X (2-,,^ 2;'"), locating two points in the required curve.
Since the surface is symmetrical with reference to the plane of the circle of the gorge, the meridian curve in vertical projection will be symmetrical with reference to the vertical projection of the circle of the gorge. Therefore, having determined the points x'' and x'" in the vertical projection of the curve, corresponding points 1/" and y"' below m'-n' may be obtained by drawing U-u' parallel to m'-n' and at the same distance below m'-n' as T-t' is above, and by taking 1/" and y'" at the same distance from a'-b' as x" and x'". By this process we may find as many points in th« curve as may be desired.
OF SINGLE CURVATURE
301. General Instructions. Note carefully the conditions imposed by the problem ; then by an application of the principles already established with reference to tangency, determine at least two
gency and must be a line of the required plane (see Section 226). Since the required plane will be tangent to the surface all along this element of tangency, a straight line tangent to the surface at any point on this element will be a line of the required plane (see Section 226).
Case 1. When the base of the cylinder is a circle on H. Construction, In Fig. 119 let A-B represent the axis of the cylinder, and let 0, assumed as in Section 234, represent the point on the surface.
Through d, draw S-d,-Sf tangent to the circular base at d.. This is a line of the required plane, since it is tangent to a curve of the surface at a point on O-I). As this tangent is also in H it is the required horizontal trace. To draw the required vertical trace, connect S with e' and produce.
Cheek. Through F^ any point on the element 0-7), draw F-G parallel to s-S. This must be a line of the required plane, since it is drawn through a point F in the plane parallel to a line s^-S also in the plane, and
Through d, draw d^-g^ tangent to the horizontal projection of the base. The line d-g, is the horizontal projection, and the line d'-a'-c' is the vertical projection of a line tangent to the base of the cylinder at the point D on the element 0-D., and therefore a line of the required plane. D-G pierces H at g, and pierces V at k'^ two more points in the required traces. The two traces S-s, and S-s' are now located.
Construction. Let the cylinder be represented as in Fig. 121. . In assuming the point upon the surface, take the horizontal projection o, at random. Through this point draw a profile plane cutting the surface of the cylinder in the circumference of a circle
tion 0-0 jj. Therefore either Ojj or hjj may be taken as the revolved position of the point upon the surface. Let us take the point 0, which in this revolved position is vertically projected at o^ but in true position is vertically projected at o'.
The element 0-D through 0 is a line of the required plane, and since this line is parallel to G-L^ we know that the traces of the required plane will both be parallel to G-L,
center is Cjj,
This line is the revolved position of a line tangent to a curve of the surface at a point on 0-D, and therefore is the revolved position of a line of the required plane. The line JE-F in true position pierces H at e^ a point in the required horizontal trace, and pierces V in f\ a point in the required vertical trace. The two traces S-s^ and S-s' are now located.
in the traces already found.
303. Problem 179. Given a cylinder whose base is a circle on V and whose axis is oblique to H and V ; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
304. Problem 180. Given a cylinder whose axis is oblique to II and F, the plane of whose base is perpendicular to H but oblique to F, and the vertical projection of whose base is a circle; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
305. Problem 181. Given a cylinder whose axis is [^ = 0, 4, 0 ; ^ = 0, 8, 6] and whose base on H is a circle of S-unit radius ; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
306. Problem 182. Given a cylinder whose axis is oblique to H and V and whose base is a circle in a plane parallel to H and above it ; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
Analysis. The required plane will contain an element of the surface of the cylinder. Therefore a straight line through the given point and parallel to the elements of the cylinder will be a line of the required plane (see Section 42) and should pierce H and V in points of the required traces.
Since the required plane will be tangent to the surface all along the element of tangency, any plane oblique to the elements of the cylinder will cut from the surface a curved line, from the auxiliary line parallel to the elements a point, and from the required plane a straight line passing through this point and tangent to the curve at a point on the element of tangency. Therefore, if through any point of the auxiliary line we draw a plane cutting from the surface of the cylinder a curved line, the straight line through the assumed point and tangent to the curve will be a line of the required plane.
cylinder, and let 0 represent the point assumed without the surface.
Through 0 draw 0-1) parallel to the elements of the cylinder and produce it to pierce // at d^ . Through d^ draw s-d-e-S tangent to the circular base at e, . According to analysis this is a line of the required plane, and since it is in H^ it is the required horizontal trace. Through 0 draw 0-G parallel to s-S piercing F at ^' . S-g'-s' is the required vertical trace.
Since from the point c?, another straight line may be drawn tangent to the base of the cylinder, another plane answering the conditions of the problem may be constructed.
Through F^ the point in which 0-D pierces the plane of the base of the cylinder, draw a rectilinear tangent to the curve of the base. This tangent will be vertically projected in f-g\ tangent to the vertical projection of the base, and horizontally pro.jected in f-g -a f. F-G is by analysis a line of the required plane and pierces H at I, and pierces V at m'. S-s, drawn through c?, and l^
In true position this line
pierces ^ at 6?,, a point in the required horizontal trace ; and pierces V at e\ a point in the required vertical trace. The two traces S-s, and S-s' are now located.
The element of tangency is that one determined by the point K, Since through o^ another straight line may be drawn tangent to the circle Cjj, another plane answering the conditions of the problem may be constructed.
Check. Through some point of the element of tangency draw a profile plane cutting from the cylinder a circle. A rectilinear tangent to this circle at the point assumed is a line of the required plane and should pierce H and V in the traces already located.
point tangent to the cylinder.
310. Problem 186. Given a cylinder whose axis is oblique to H and V and whose base is a circle in a plane parallel to V and in front of it ; required to assume a point without the surface and to draw through this point a plane tangent to the cylinder.
311. Problem 187. Given a cylinder whose axis is [^ = — 4, 0, — 4 ; ^ = — 4, 6, 4] and whose base on V is a circle of S-unit radius; also given the point 0 = 2, 4, 2 ; required to draw through the point a plane tangent to the cylinder.
Through any point D of M-N draw D-E parallel to A-B. D-E pierces H at e, and pierces F at/'; M-N pierces H at g, and pierces Fat k^. The plane U whose traces are located by the
points just found will, by analysis, be parallel to the required plane. The horizontal trace of the required plane, then, must be parallel to U-u, and must also be tangent to the circular base on H whose center is a^ . Therefore draw the horizontal trace S-s^ under these conditions, and through S draw the vertical trace S-s' parallel to
Through any point D
of the given line M-N draw D-E parallel to the axis A-B. The plane of the two lines M-N and D-E is parallel to the required plane. D-E pierces the plane of the base of the cylinder at E^ and M-N pierces the same plane at F. The line E-F is the intersection of the auxiliary plane with the plane of the base of the cylinder, and must be parallel to the intersection of the required plane with the plane of the base.
The intersection of the required plane with the plane of the base must also be tangent to the curve of the base. Therefore k-g-li^ drawn parallel to e-f^ and tangent to the circle whose center is a^ is the horizontal projection, and k'-g'-V is the vertical projection of the intersection of the required plane with the plane of the base. K-G-L, which is a line of the required plane, intersects // at kf and intersects V at l\ points respectively in the horizontal and vertical traces of the required plane.
auxiliary plane must be parallel to the required plane.
Draw a profile plane P cutting the cylinder in the circle whose center is C, and cutting the auxiliary plane U in the line F-G. The intersection of the required plane by the profile
plane must be parallel to F-G and be tangent to the circle C, since the required plane is both parallel to the auxiliary plane and tangent to the surface of the cylinder (see Section 226).
The line k-ljj drawn parallel to ^,-^^ and tangent to the circle Cjj is the revolved position of the intersection of the required plane with the profile plane. In true position K-L pierces H at k, and pierces V at V, points respectively in the horizontal and vertical traces of the required plane. The two traces S-s^ and S-s' may now be drawn.
Since another straight line tangent to the circle Cjj and parallel to f-Qji may be drawn, another plane answering the conditions of the problem may be constructed.
Check. Through some point on the element of tangency draw a straight line parallel to the given line M-N^ and note whether this line pierces H and V in the traces now located.
313. Problem 189. Given a cylinder whose axis is oblique to H and V and whose base is a circle on V ; required to assume a straight line and to draw a plane tangent to the cylinder and parallel to the line.
314. Problem 190. Given a cylinder whose axis is oblique to H and F, the plane of whose base is perpendicular to H but oblique to F", and the vertical projection of whose base is a circle ; required to assume a straight line and to draw a plane tangent to the cylinder and parallel to the line.
315. Problem 191. Given a cylinder whose axis is parallel to G—L; required to assume a straight line in a profile plane a7id to draw a plane tangent to the cylinder and parallel to the line.
316. Problem 192. Given a cylinder whose axis is oblique to H and V and whose base is a circle in a plane parallel to H and above it; required to assume a straight line parallel to G-L and to draw a plane tangent to the cylinder and parallel to the line.
Analysis. Since the surface of a cone is of single curvature, the rectilinear element of the surface through the point of tangency is the element of tangency, and is therefore a line of the required plane (see Section 226).
- Since the required plane will be tangent to the surface all along this element, a line tangent to the surface at any point on this element will be a line of the required plane.
Fig. 128
df draw S-d^-s^ tangent to the circular base at d, . This is a line of the required plane, because it is tangent to a curve of the surface at a point on 0-D. Since this tangent is also in H, it is the required horizontal trace. Connect S and e' by a straight line and produce it to represent the required vertical trace.
Check. Through F, any point on the element of tangency 0-D, draw F-G parallel to s^-S. This line must be a line of the required plane, since it is drawn through a point F in this plane and parallel to a line s^-S also in this plane, and should therefore pierce V in the vertical trace already found.
to V hut oblique to H.
Construction. In Fig. 129 let A-B represent the axis of the cone, let the circle whose center is a^ represent the horizontal projection of the base, let the straight line g'-k'-a'-d' represent the vertical projection of the plane of the base, and let 0 represent the point on the surface.
Through d, draw d-g, tangent to the horizontal projection of the base. The line d-g, is the horizontal projection and d'-g' is the vertical projection of a line tangent to the base of the cone at a point D on the element B-O-D, and therefore a line of the required
318. Problem 194. Given a
cone whose axis is oblique to H and V and whose base is a circle on V ; required to drau) a plane tangent to the cone at a point on the surface.
a plane tangent to the cone at a point on the surface.
320. Problem 196. Given a cone whose axis is oblique to H and V and whose base is a circle in a plane parallel to H and above it ; required to draw a plane tangent to the cone at a point on the surface.
According to analysis this is a line of the required plane, and since it is in iT, it is the required horizontal trace. Through S and e' draw the required vertical trace S—s'.
Through F, the point in which B-0 intersects the plane of the base of the cone, draw a rectilinear tangent to the curve of the base. This tangent will be vertically projected in f-g'^ tangent
of the required plane, pierces If and V in the traces now located.
322. Problem 198. Given a cone whose axis is oblique to H and V and whose base is a circle on V ; required to assume a point tvithout the surface and to draw through this point a plane tangefit to the cone.
323. Probem 199. Given a cone whose axis is oblique to H and V, the plane of whose base is perpendicular to V but oblique to H, and the horizontal projection of whose base is a circle ; required to assume a point without the surface and to draw a plane through this point and tangent to the cone.
Analysis. Since the required plane must contain the vertex of the cone, a straight line through the vertex of the cone and parallel to the given line will be a line of the required plane. A plane containing this auxiliary line and tangent to the cone will be the required plane.
vertex of the cone and the point of tangency F on the base.
Since another straight line may be drawn through d, and tangent to the circular base, another plane answering the conditions of the problem may be constructed.
V in the traces now located.
326. Problem 202 . G-iven a cone whose aMS is oblique to H and V and whose base is a circle on V; required to assu^ae a straight line in a profile plane and to draw a plane tangent to the cone and parallel to the line.
327. Problem 203. Given a cone whose axis is oblique to H and F, the plajie of whose base is perpendicular to H but oblique to r, and the vertical projection of whose base is a circle ; required to assume
328. Problem 204. Given a cone whose axis is oblique to If and V and whose base is a circle in a plajie parallel to V and in front of it; required to assume a straight line and to draw a plaiie tangent to the cone and parallel to the line.
Analysis. Since the surface of the helical convolute is of single curvature, the rectilinear element of the surface through the point of tangency will be the element of tangency, and therefore be a line of the required plane (see Section 226).
Since the required plane will be tangent to the surface all along the element of tangency, a straight line tangent to the surface at any point of this element of tangency will be a line of the required plane.
Check. Through 0, or through any point on the element of tangency, draw a straight line parallel to S-s^ and note whether it intersects V in the vertical trace already located.
Analysis. A plane through the given point and intersecting the surface will cut from the surface a line, usually curved, and from the required plane a straight line running through the given point and tangent to the curve. Therefore, through the given point pass a plane cutting from the surface a curved line. Through the given
point and tangent to this curved line draw a straight line. This straight line is a line of the required plane and will pierce H and V in points of the required traces.
The element of the surface through the point of tangency just determined on the curve of the surface is the element of tangency and is a line of the required plane.
Through 0 pass the plane U parallel to II. The plane U cuts the helical directrix at the point i>, and since the plane is parallel to B, it cuts the surface of the convolute in a curve similar to the curve cut from the same surface by the plane R, but starting from the point 2>.
The plane U cuts the element whose horizontal projection is e-ff at a point horizontally projected at ^^ where e^-g^ is equal to the rectified arc e^-d^ (see Section 216).
In the same way other points in which the plane U cuts the elements of the surface may be found. The curve d^-g-m-n^ • • • is then the horizontal projection of the curve cut from the helical convolute by the plane U.
Through o^ draw o-q^ tangent to the curve d-g-m^-n^ at the point q,. The line o^-q, is the horizontal projection and the line o'-q' is the vertical projection of a straight line through 0 and tangent to the curve cut from the surface by the plane U. 0-Q is then a line of the required plane and pierces V in r\ a point in the required vertical trace. Through Q and tangent to the helical directrix draw the element of tangency Q-W-X, piercing j^ at w^ and piercing V at x\ points in the required traces. Through w^ draw the required horizontal trace S-s^ tangent to the base of the surface at w^. Through S and x' draw the required vertical trace S-8\ which should also pass through r', and check the work.
Analysis. Assuming the axis of the convolute perpendicular to H^ with some point on the given line as a vertex construct a cone whose elements shall make with H the constant angle which the elements of the convolute make with H.
Through the given line pass a plane tangent to this auxiliarycone. Such a plane will be parallel to the required plane, since it contains the given line and an element on the cone which is parallel to the element of tangency on the convolute.
of the convolute parallel to V. The elements of the right circular cone generated by the revolution of the line n'-f about the vertical line through n' will make the same angle with H as the elements of the convolute. The circle whose center is n^ is the base of the cone and n' is the vertex of the cone.
Through M-N and tangent to the cone draw the plane U (see Section 321). The horizontal trace U-u^ will be tangent to the circular base. The vertical trace U-u' will pass through w'.
Tangent to the base of the convolute and parallel to U-u^ draw S-Sj^ the required horizontal trace. Through S and parallel to U-u^ draw S-s'^ the required vertical trace.
conditions of the .problem.
Since the convolute is unlimited in extent, having its base in the form of a spiral, an unlimited number of planes answering the conditions of the problem may be constructed.
Oheok. Through any point, as K, on the element of tangency draw a straight line K-L parallel to /S-s,, and note whether it pierces V in the vertical trace already located.
332. General Instructions. By Section 226 straight lines which are tangent to a surface of double curvature at a point on the surface, lie in a plane tangent to the surface at this point. Therefore through the point of tangency draw two planes cutting from the surface two simple curved lines intersecting at the point of tangency. Tangent to these curved lines at the point of tangency draw two straight lines which shall determine the required plane.
When the given surface is one of revolution, it will be found convenient to use as the cutting planes the meridian plane and a plane perpendicular to the axis.
Sometimes an auxiliary surface may be passed tangent to the given surface at the point of tangency; then of course a plane tangent to the auxiliary surface at the point of tangency will also be tangent to the given surface at the point of tangency.
0, assumed as in Section 287, represent the point on the surface.
By Analysis 1 draw through 0 a vertical meridian plane T, cutting the sphere in a great circle. Revolve T about its horizontal trace into H. The center of the great circle will fall at Cjj and the point of tangency will fall at Ojj. Through Ojj draw Ojj-a^ tangent to the circle Cjj. This last line is the revolved position of a tangent to the sphere at the point 0. This tangent in true position pierces H at a,, a point in the required horizontal trace.
SURFACES OF DOUBLE CURVATURE
Through 0 pass another plane TJ parallel to //. This plane cuts the sphere in a small circle whose horizontal projection is o,-o„-5, and whose vertical projection is o^^-V . Through 0 draw 0-D tangent to the small circle at 0. 0-D is another line of the required plane, and pierces V at d! ^
surface at this point,
336. Problem 211. Given a sphere in the second quadrant with its center equidistant from H and V ; required to assume a point upon the surface and to pass a plane tangent to the surface at this point.
Analysis 1. See Section 332.
Ajialysis 2. Determine the meridian curve of the surface which contains the given point, and draw a rectilinear tangent to the curve at this point. If this tangent is revolved about the axis of the ellipsoid as an axis, it will generate a conical surface which will be tangent to the surface of the ellipsoid in the circumference of a circle containing the point of tangency (see Section 284).
The remainder of the construction corresponds with that given in connection with the sphere (see Section 333). Check. Construct a*ccording to Analysis 2.
338. Problem 213. Solve the above problem by Analysis 2.
339. Problem 214. Given an ellipsoid of revolution with the long axis perpendicular to V; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
340. Problem 215. Given an ellipsoid of revolution with the long axis parallel to G—L; required to assume a point upon the surface and to draw a plane tangent to the surface at this point.
revolution.
Analysis. The directions given in connection with the solution of the foregoing problems will be sufficient for the solution of all problems relative to tangency of planes to surfaces of revolution.
line and tangent to a given sphere.
Analysis 1. After the required plane is constructed, an auxiliary plane through the center of the sphere and perpendicular to the given line will cut from the sphere a great circle, from the line a point, and from the required plane a straight line passing through the point and tangent to the great circle. Therefore, through the center of the sphere and perpendicular to the given line, pass a plane cutting the sphere in a great circle and cutting the line in a point. Through this point and tangent to the circle draw a straight line. This line together with the given line will determine the required plane.
Analysis 2. If through any point of the given line a series of rectilinear tangents to the sphere be drawn, they will form the elements of a cone whose axis will contain the point on the line and the center of the sphere. The surface of this cone will be tangent to the sphere in the circumference of a small circle whose plane will be perpendicular to the axis of the cone.
Analysis 3. If from each of two points on the given line a series of rectilinear tangents to the sphere be drawn, they will form the elements of two cones whose axes will contain the points on the line and the center of the sphere, and whose surfaces will be tangent to the sphere in the circumferences of small circles, which may be taken as the bases of the cones. The planes of these small circles will be perpendicular to the axes of their respective cones, and will intersect in a straight line which will be a chord of the sphere.
The circumferences of these two circles will, as a rule, intersect in two points on the surface of the sphere, which will be the points in which the chord of the sphere intersects the surface of the sphere, and which will be the points at which the required planes will be tangent to the sphere. For a straight line drawn through the vertex of either cone and one of these points of tangency is an element of this cone and will therefore be tangent to the sphere at this point of tangency. A straight line through the vertex of the other cone and this same point of tangency is an
Following Analysis 1, pass the plane U through the point C and perpendicular to M-N (see Section 165). Find the point D in which U is intersected by M-N (see Section 151).
U will fall at Cj^. Through d^ draw ^jr^n-ft tangent to the circle Cjj at Cjf. The straight line of which ^ji-d^f-fj is the revolved position passes through D and is tangent to the great circle cut from the sphere by ?7, and is therefore a line of the required plane. Produce this line to meet H in /,. Through /, and a^ draw S-s^^ the required horizontal trace. Through S and h' draw S-s', the required vertical trace.
Chech, Assume any point, as (7, in the vertical trace of U, After the revolution of U^ G will take the position ^^^, and the vertical trace U-u' will take the position U-gji, The point kjj^ the point in which U-gjj intersects e^-/,, is the revolved position of the point in which E-F crosses the vertical trace of Z7, or, in other words,
Following Analysis 2, take the point ^ — the point in which M-N pierces H — as the vertex of a cone whose elements are tangent to the sphere. The lines a-d^ and a-e^^ each tangent to the horizontal projection of the sphere, will represent the horizontal projections of the extreme elements of the cone. The line a-c^ represents the horizontal projection of the axis of the cone, and U-d-e-iij represents the horizontal trace of the plane of the circle of tangency, which circle may be taken as the base of the cone.
Determine the point F in which M-N intersects U. Revolve U about its horizontal trace U-u^ as an axis into H. F will fall at fjj^ and the circle of tangency will fall at d-hjj-e^. Through fjj draw fii-kji-lj tangent to the circle d^-kj^-e, at the point kj^.
This line is, by Section 321, the revolved position of a line of the plane containing the line M-N and tangent to the cone, and is therefore a line of the required plane.
In true position this line F-K-L pierces H at Z,. Through a, and If draw the required horizontal trace S-s^. Through >S^ and h' draw the required vertical trace S-s'.
Chech. The required plane is tangent to the cone along the element A-K., and since this element is tangent to the sphere at the point A', K is the point at which the required plane is tangent to the sphere. The required plane must then be perpendicular to the radius K-C. The projections of K in true position are h^ and lc\ where the distance of k' from G-L is equal to k-kj^. Therefore S-Sf and S-s' should be perpendicular respectively to k^-c, and k'-c'.
traces.
Following Analysis 3, take for the vertices of the cones the points D and E^ which are assumed upon M-N in such a way that i> is at the same distance below H as the center of the sphere.
This line of intersection will pierce the surface of the sphere in the two points in which the circumferences of the two bases intersect, and which by analysis are the points of tangency sought.
To find these points of tangency revolve the plane of the base of the cone whose vertex is D about its horizontal trace /,-^, into H. The circular base whose center is 0 will take the position of the circle whose center is Ojj, where o-Ojj is equal to the distance of (?' from G-L. The intersection of the planes of the two bases
points of tangency sought.
Through Vj, and tangent to the circle Ojj draw rjj-w^. This is the revolved position of a line of the required plane, since it is the revolved position of a straight line tangent to the sphere at the point at which the required plane is to be tangent. The line R-W in true position pierces // at w^ and pierces V at x\ where x-x' is equal to Xj-^Xjj measured on a straight line, x-x^^ perpendicular to Wf-Xf.
Check. The two traces should cross G-L at the same point. Or, the two traces, S-s^ and S-s\ should be perpendicular respectively to the two projections of the radius R-C.
may be constructed.
343. Problem 218. Given a sphere whose center is in G-L^ and given a straight line parallel to G-L and in the third quadrant; required to draw a plane contaiyiing the line and tangent to the sphere,
344. Problem 219. Given a sphere whose center is in G-L^ and given a straight line situated in a profile plane and in the third quadrant; required to pass a plane through the line and tangent to the sphere.
345. Problem 220. Given a sphere in the second quadrant equidistant from H and F, also given a straight line in the first quadrant; required to pass a plane through the line and tangent to the sphere.
INTERSECTION OF SURFACES BY LINES
346. General Instructions. If the given line is a straight line or a curved line of single curvature, pass an auxiliary plane through the line and determine its intersection with the given surface. The point or points in which the given line intersects the lines cut from the surface by the auxiliary plane will be the points sought.
Since an infinite number of planes may be drawn through a straight line, it will be wise, in connection with straight lines, to use those auxiliary planes which will cut from the surface the simplest lines. If the given line is a curved line of single curvature the plane of the curve must be used as the auxiliary plane.
347. On the Character of Lines in which Planes intersect Surfaces. Since prisms and pyramids have plane surface faces, the intersections of these faces by planes will always be straight lines whatever the position of the cutting plane.
Since the elements of cylindrical surfaces are parallel straight lines, the intersections of such surfaces by planes which are parallel to the elements are parallel straight lines.
Since the elements of conical surfaces all pass through the vertex, the intersections of such surfaces by planes which contain the vertex will be straight lines passing through the vertex.
and r, the two points required.
350. Problem 223. Find the points in which a straight line intersects the surface of a prism whose edges are oblique to II and V.
face of an hexagonal prism.
352. Problem 225. Given a hollow square prism ; required to find the points in which a given straight line intersects
intersects the surface of the frustum of a square pyramid.
356. Problem 229. Given a hollow square pyramid ; required to find the points in which a given straight line intersects the outer and the inner surface of the pyramid.
required.
358. Problem 231. Given a right circular cylinder in the third quadrant with axis parallel to G-L; required to find the points in which a given straight line intersects the surface of the cylinder.
359. Problem 232. Given a right circular cylinder in the third quadrant with axis perpendicular to H ; required to find the points in which a given straight line intersects the surface of the cylinder.
Through J, the vertex of the cone, and parallel to the given line, draw A-D piercing H at d^ . U-d-h^-Uf is the horizontal trace of the auxiliary plane. This plane intersects the surface of the cone in two elements, A-E and A-F, which are
of a cone.
364. Problem 237. Given a hollow cone; required to find the points in which a given straight line intersects the inner and the outer surface of the cone.
intersects the surface of a sphere.
Analysis. Since the intersection of a sphere by any plane is a circle, the auxiliary plane may be passed through the line at random. ^ig. 140
To determine the points in which M-N intersects this circle, revolve the plane U about its horizontal trace into H, The center A of the circle cut from the sphere falls at a^, and the line M-N falls at mj^-iij^. The points Xjj and ^^, the points in which mjj-rijj intersects the circumference of the circle a^, are the required points in revolved position. The points X and F, whose projections are {x,^ x') and (y^ y') respectively, are the required points in true position.
outer siCrface.
Analysis. Take as the auxiliary plane one of the projecting planes of the given line, as in the preceding problem. Find the two semicircles in which this plane intersects the outer and inner surfaces of the hemisphere. The points in which the given line intersects these semicircles will be the required points.
367. General Instructions. Pass a series of auxiliary planes intersecting both the given plane and the given surface in lines. The points in which these two sets of lines intersect will be common to both the plane and the surface, and will therefore be points in their line of intersection.
Pass the auxiliary planes in such a way as not only to cut from the given surface the simplest lines, but also in such a way as to simplify the work of construction.
found convenient to pass the auxiliary planes through the edges.
If the given surface is one of revolution, it will be found convenient to pass the auxiliary planes perpendicular to the axis of revolution, since such planes will cut circumferences of circles from the surface.
The plane of the face A-D-G-E, which is the plane U, contains the two edges A-E and D-G. This plane, which may be used as an auxiliary plane, cuts S in the line K-L, crossing A-E and D-G at X and Z respectively. X-Z is the line of intersection between the plane S and the face A-D-G-E.
In this case the auxiliary planes are perpendicular to H^ since the edges of the prism are perpendicular to H, The method of construction is the same when the edges are oblique to i/, but the auxiliary planes will then be oblique to H.
volve the plane >S, in Fig. 147, about S-8^ as an axis into H. The three vertices X, F, and Z will fall respectively at a:^, yj^^ and Zj^. The true size of the intersection is Xjj-yj^-Zjj (see Section 87).
development.
Starting with this face in the plane, roll the prism from left to right, bringing first the face B-D-G-F and later the face A-D-G-E into coincidence with the original plane.
Since the plane of the base of the prism is perpendicular to the edges of the prism, the straight line A-B-D-A\ where A-B, B-D, and D-A' are made equal respectively to a-b^^ h-d^, and d^-a, of Fig. 147, may represent the development of the base of the surface.
The edges of the prism will, in development, take the positions A-E, B-F^ D-G^ and A'-E\ all perpendicular to A-A' and all equal to the altitude of the prism.
prism.
The vertices of the triangle of intersection, X- Y-Z of Fig. 147, will in development take the positions A', F, Z, and X' (Fig. 148) where A-X^ B- F, D-Z^ and A'-X' are made equal respectively to a^-x', h'-y', d'-z\ and a'-x' of Fig. 147. The line X-Y-Z-X^ of Fig. 148 represents the line of intersection in development.
The plane surface E-X-Y-Z-X'-E'-E (Fig. 148) is the templet or pattern of that portion of the surface of the prism below the plane S^ and might be used in the construction of a duplicate prism to take the place of that portion of the prism now there.
370. Problem 242. Given a triangular prism whose edges are oblique to IT and F", and given a cutting plane perpendicular to the edges of the prisyn ; required to find the intersection^ the true size of this intersectio7i^ and the development of the surface of the prism.
Note. In developing this surface use the cutting plane as a basal plane.
371. Problem 243. Given a square prism whose edges are parallel to G—Ly and given a cutting plane oblique to H and V ; required to find the intersection^ the true size of this intersection, and the development of the surface of the prism.
372. Problem 244. Given an hexagonal prism whose edges are oblique to H and F, and given a cutting plane parallel to H ; required to find the intersection., the true size of this intersection., and the development of the surface of the prism.
Revolve the plane S in Fig. 149 about S-s' into V. The points X, r, Z, and W will fall at x^, y^, z^\ and w^ respectively (see Section 91), and x^'-y^'-z^^-w^ will represent the true size of the intersection.
The triangle A-B-D, Fig. 150, in which A-B, B-D, and A-D are equal respectively to A-B,* h-d^^ and A-D of Fig. 149, represents the face A-B^D of Fig. 149. Then since the face A-D-E^ Fig. 149, is revolved about the edge A-D as an axis, it will in development take the position A-D-E, Fig. 150, where A-I), D-E, and A-E are equal respectively to A-D, dj-e,, and A-E of Fig. 149.
structed.
The vertices of the polygon of intersection will in development take the positions X, r, Z, TV, and X' in Fig. 150, where A-X, A-Y, A-Z, A-W, and A-X' are made equal respectively to ^-X,f A-Y, A-Z, A-W, and A-X of Fig. 149.
The surface A-B-D-E-F-B' , Fig. 150, represents the development of the surface of the pyramid. The broken line X- Y-Z- W-X' represents the development of the line of intersection. The surface X-B-D-E-F-B'-X'-W-Z-Y represents the development of that portion of the surface of the pyramid below the plane >S^.
In cases of oblique and irregular pyramids the edges of the pyramid will not be equal, neither will the sides of the base necessarily be equal, as in the case just considered.
374. Problem 246. Given an oblique pentagonal pyramid, and given a cutting plane perpendicular to V hut oblique to H ; required to find the intersection, the true size of this intersection, and the development of the surface of the pyramid.
375. Problem 247. Given a triangular pyramid, and given a cutting plane parallel to G—L hut oblique to Hand V ; required to find the intersection, the true size of this intersection, and the development of the surface of the pyramid.
376. Problem 248. Given an oblique hexagonal pyramid, and given a cutting plane parallel to H ; required to find the intersection, the true size of this intersection, and the development of the surface of the pyramid.
377. Problem 249. To find the intersection of a right circular cylinder whose axis is perpendicular to H by a plane ; to draw a rectilinear tangent to the curve of intersection ; to find the true size of the intersection, and to develop the surface of the cylinder.
Pass an auxiliary plane T through the axis and perpendicular to S-Sf. T cuts the cylinder in two elements, A-B and D-E, and intersects S in a straight line F-G. F-G crosses A-B and D-E at K and E respectively, two points of the required curve of intersection.
Owing to the position which the plane T occupies with reference to S-Sj, the points K and E must be respectively the highest and the lowest points of the curve of intersection.
Pass another auxiliary plane U perpendicular to H and parallel to S-Sj. The plane U cuts the cylinder in two elements, L-M and N-0, and intersects the plane S in the straight line P-O-M. The line P-O-M crosses L-M and N-0 at M and 0 respectively, two more points of the required curve.
Case 2. To draw a rectilinear tangent to the curve of intersection. Analysis. A rectilinear tangent to the curve of intersection will be tangent to the surface of the cylinder at the given point, and will therefore lie in a plane tangent to the cylinder along the element passing through this point. The rectilinear tangent will also be in the plane of the curve which is the cutting plane. The required line will therefore be at the intersection of these two planes.
Since a rectilinear tangent to
a curve shows the direction of the curve at the point of tangency, such tangents, when determined in sufficient number, are helpful in drawing the curve through the points already located. Case 3. To find the true size of the intersection. Analysis and Construction. See Fig. 151. Revolve the plane S^ which is the plane of the curve of intersection, about S-s' into V. Any point, as Jf, will fall at m^, and other points may be found in the same way. The curve determined by the revolved positions of these points is the required curve of intersection.
Case 4. To develop the surface.
Aiialysis and Construction. Take the plane W^ Fig. 151, as the plane of development. Starting with the element of tangency N-0 in this plane, roll the cylinder along the plane away from F, bringing the successive elements into contact with W.
Since the plane of the base of the cylinder is perpendicular to the elements, the curve of the base will roll out into a straight line perpendicular to the elements.
The character of the development is shown in Fig. 152, where N-0 represents the element of tangency, and where N-N' drawn perpendicular to N-0 and made equal to the rectification of the curve of the circular base of the cylinder represents the development of the base.
The elements through A, Z, i), etc., in Fig. 151, will take the positions A-K, L-M, D-E^ etc., in Fig. 152, where N-A^ A-L, L-D, etc., are made equal respectively to the rectified arcs w,-a,, a-lf^ If-df, etc., of Fig. 151.
The points 0, K^ Jf, E, 0, Fig. 151, which are situated upon the elements just named, will in development take the positions 0, K, M, E, 0' in Fig. 152, where N-0, A-K, L-M, etc., are made equal respectively to the distances of the same name in Fig. 151.
378. Problem 250. Given a right circular cylinder whose axis is perpendicular to H, and given a cutting plane; required to find the intersection hy passing the auxiliary planes parallel to H.
379. Problem 251. G-iven a right circular cylinder whose axis is perpendicidar to H, and given a cutting plane which is parallel to G-L hut oblique to H and V; required to find the intersection, to draw a rectilinear tangent to the curve of intersection, to find the true size of the intersection, and to develop the surface of the cylinder.
381. Problem 253. To find the intersection of an oblique cylinder by any plaiie^ to draw a rectilinear tangent to the curve of intersection^ to show the true size of the intersection, and to develop the surface of the cylinder.
of the cylinder and perpendicular to H.
Construction. Let the cylinder be represented as in Fig. 153, and let S^ in this case assumed perpendicular to the elements of the cylinder, represent the given cutting plane.
Pass an auxiliary plane T through the axis and perpendicular to H. This plane cuts the cylinder in two elements, A-B and D-E, and intersects the plane S in F-G. F-G crosses A-B and D-E at B and E respectively, two points in the required curve of intersection.
Owing to the position of the plane T with reference to S-s^^ the points B and E will be respectively the lowest and the highest points of the curve of intersection.
Pass another auxiliary plane U parallel to T. This plane cuts the cylinder in two elements, K-L and M-N, and intersects the plane S in 0-P, where 0-P is necessarily parallel to F-G. 0-P crosses K-L and M-N at L and N respectively, two more points in the required curve.
Analysis. See Problem 249, Case 2.
Construction. See Fig. 153. Let it be required to draw a rectilinear tangent to the curve of intersection at the point L. Draw the plane W tangent to the cylinder along the element K-L (see Section 302). The intersection of the planes 1^^ and S is Q-L-B, the required tangent.
will fall at 5^, and other points may be found in the same way. The curve traced through the points thus found is the curve required. The tangent E-L will, when revolved, take the position r-ljj and be tangent to the revolved position of the curve. Case 4. To develop the surface.
a line of reference.
Construction. Take the plane W, Fig. 153, as the plane of development, and take the point of observation to the left of the plane. Starting with the element of tangency A-i, in this plane, roll the cylinder along this plane toward F, bringing the successive elements of ^he surface into contact with W.
perpendicular to K-L and equal in length to the rectification of the true size of the right section of the surface made by tlie plane S^ represents the development of this section.
The points X, B, X, E, etc., of Fig. 153 will, in Fig. 154, take the positions X, B^ X, E^ etc., where the distances L-B^ Z-X, L-E^ etc., are made equal to the rectified arcs Iji-hji^ hi~^^n~^in ^H~^H~^H—^Ht etc., of Fig. 153.
The elements through the points i, i?, E^ X, etc., Fig. 153, will in development, since they are perpendicular to the plane of the section, take the positions L-K^ B-A^ E-D^ etc.. Fig. 154.
The points K^ A, D, etc.. Fig. 153, which are situated upon the elements just named and also situated in the base of the surface, will in development take the positions if, A, Z>, etc., Fig. 154, where the distances L-K, B-A, E-D, etc., are made equal to the actual distances of the same name in Fig. 153.
The tangent r-k^^ tangent to the base of the cylinder at the point A:,, Fig. 153, will in development take the position B-K, Fig. 154, where L-R is made equal to Ijj-r, of Fig. 153.
382. Problem 254. G-iven an oblique cylinder with its axis in a profile plane, and given a cutting plane parallel to G-L hut oblique to H and V; required to find the intersection, to draw a rectilinear tangent to the curve of intersection, to find the true size of the intersection, and to develop the surface of the cylinder.
383. Problem 255. Given a right circular cylinder with its axis parallel to G-L, and given a cutting plane oblique to H and V; required to find the intersection, to find the true size of the intersection, and to develop the surface of the cylinder.
384. Problem 256. Given an oblique cylinder and a cutting plane oblique to the elements of the cylinder; required to find the intersection, to draw a rectilinear tangent to the curve of intersection, to fijid the true size of the intersection, and to develop the surface of the cylinder.
385. Problem 257. To find the intersection of a right circular cone hy an oblique plane, to draw a rectilinear tangent to the curve of intersection, to find the t7'ue size of the intersection^ and to develop the surface of the cone.
Analysis and Construction. See Fig. 155. Revolve the plane S about S-s, into H. After revolution any point, as N, will fall at n^j^ and other points may be found in the same way.*
Analysis and Construction. Take the plane Z, Fig. 155, as the plane of development. Starting with the element of tangency, R-P, in this plane, roll the cone along this plane toward V, bringing the successive elements into contact with the plane Z.
Since the cone is one of revolution and the plane of the base is perpendicular to the axis, the curve of the circular base will roll out into the arc of a circle whose radius is equal to the slant height of the cone.
The character of the development is shown in Fig. 156, where B represents the vertex of the cone. The arc P-D-M-Q-A-L-P\ with center at B^ with radius equal to the slant height of the cone, and equal in length to the rectification of the curve of the circular base of the cone, represents the development of the base.
To represent the elements in development, make P-i>, P-M., P-Q-, etc.. Fig. 156, such that the rectification of their arcs shall be equal to the rectification of the corresponding arcs of the same name upon the base'of the original cone, and connect these points with B.
etc., equal respectively to the distances of the points R, K^ 0,X, etc., on the surface of the cone, from the vertex, and trace the curve E-K-0-X-G-N-R' through these points.
In Fig. 155 the true distance from ^ to A^ is expressed by the distance h'-n\ since the element B-L is parallel to V. The distance B-0 is expressed by h'—o' for the same reason.
The distance from B to any other point on the surface may be found by revolving the cone about its axis until the element on which the point stands is parallel to V. The vertical projection of the required distance in this position will be equal to the distance itself.
For example, suppose it is required to find the distance B-X on the element B-Q. After revolution the element B-Q will take the position B-M^ vertically projected at h'-m'. The point x' will take the position x" and h'-x'^ will be the measure of the distance B-X.
The tangent R-I of Fig. 155 will in development take the position ^-/, Fig. 156, where P-I is drawn tangent to P-D-M-A-F' at P, and where P-I is made equal to p,-i,, Fig. 155.
386. Problem 258. Given a right circular cone with axis perpendicular to H, and given an intersecting plane oblique to H and V; required to find the intersection hy passing auxiliary plaiies parallel to H.
387. Problem 259. Given a right circular cone with axis perpendicular to i/, and given an intersecting plane parallel to H; required to determine the character of the intersection.
388. Problem 260. Given a right circular cone with axis perpendicular to H^ and given an intersecting plane passing through the axis; required to determine the character of the intersection.
389. Problem 261. Given a right circular cone with axis perpendicular to H^ and given an intersecting plane making a smaller angle with H than the elements of the cone; required to determine the character of the intersection.
of a right circular cone is cut by a plane perpendicular to the axis, the curve of intersection is the circumference of a circle ; and when cut by a plane containing the axis, the intersections are elements.
By examination of the results obtained in Problems 261-263, and by reference to treatises on solid and analytic geometry, it may be shown that when a right circular cone with axis perpendicular to H is cut by a plane making a smaller angle with H than the elements of the cone, the curve of intersection is an ellipse; when cut by a plane making the same angle with H as the elements of the cone, the curve of intersection is a parabola; and when cut by a plane making a greater angle with H than the elements of the cone, the curve of intersection is a hyperhola.
393. Problem 264. To find the intersection of any cone by a plane, to draw a rectilinear tangent to the curve of intersection, and to find the true size of the intersection.
Fig. 157, and let S represent the intersecting plane.
Pass the auxiliary planes through the vertex B and perpendicular to H. Then all the auxiliary planes will intersect in a common straight line through the vertex and perpendicular to H. This straight line will intersect S 2X A (see Section 151), which is therefore a point common to all the lines cut from S by the auxiliary planes.
Let T represent one of the auxiliary planes. This plane intersects the surface of the cone in two elements, B-D and B-E, and intersects the plane S in the line F-A, passing through the point A previously located. F-A crosses B-D and B-E at K and L respectively, two points in the required curve of intersection.
Another auxiliary plane U will intersect the surface of the cone in the elements B-M and B-N, and will intersect the plane S in the line I- A. I- A crosses B-M oxidi B-N dX 0 and P respectively, two more points in the required curve.
trace of the plane W tangent to the cone along the element B-L-E (see Section 317). The intersection of the planes W and S is the required tangent. This intersection pierces H at q^ and must also pass through L. Therefore Q-L is the required tangent.
For example, A-F will in revolved position fall at a^-f^. The points K and L upon this line A-F will move in planes perpendicular to S-s^ and will therefore fall at hj^ and l^j respectively, upon lines through h^ and l^ perpendicular to S-s^.
394. Problem 265. G-iven an oblique cone with base on F, and given a cutting plane oblique to G—L; required to find the intersectio7i, to draiv a rectilinear tangent to the curve of intersection^ and to find the true size of. the intersection.
395. Problem 266. Given an oblique cone tvith axis in a profile plane, and given an intersecting plane parallel to G—L but oblique to H and V; required to find the intersection, to draw a rectilinear tangent to the curve of intersection, and to find the true size of the intersection.
396. Problem 267. Given a right circular cone with axis parallel to G-L, and given a chitting p>lane oblique to G-L ; required to find the iyitersection, to draw a rectilinear tangent to the curve of intersection, and to find the true size of the intersection.
397. Problem 268. To find the intersection of any surface of revolution by a pla7ie, to draw a rectilinear tangent to the curve of intersection, and to find the true size of the, intersection.
Let T represent one of the auxiliary planes perpendicular to A-B. This plane cuts the given surface in the circumference of a circle whose vertical projection is d'-e' and whose horizontal projection is d-g-e-h,. This same plane intersects S in the straight line 6r-/i-i^ parallel to S-s^. G-K-F crosses the circumference IJ-G-E-K at G and K, two points of the required curve of intersection.
Pass a meridian plane U perpendicular to S-s^, cutting from the surface a meridian curve and cutting S in a straight line JI-L which intersects the axis at M.
To find the points in which Af-L intersects the meridian curve, revolve the plane U about the axis A-B until it is parallel to V. The vertical projection of the meridian curve will then be identical with the vertical projection of the surface, and the vertical projection of M-L will fall at m'-l", M remaining stationary. The points n" and o'\ the points in which the line m'-V crosses the vertical projection of the meridian curve, are the vertical projections of
the revolved positions of the lowest and the highest points of the required curve of intersection. The projections of N in true position will fall at n^ and ?^', and the projections of 0 in true position will fall at 0, and o'.
Case 2. To draw a rectilinear tangent to the curve.
By analyses previously given, a rectilinear tangent to the curve, cut from any surface by a plane, may be drawn whenever a plane can be drawn tangent to the surface at the point of tangency.
Analysis and Constructio7i. See Fig. 158. Revolve the plane S^ the plane of the curve, about S-s^ into H. Any point of the curve, as 0, will fall at o^^, and other points may be found in the same way.*
404. General Instructions. Pass a series of auxiliary planes so as to cut lines from the two surfaces. The points in which the lines of one surface intersect the lines of the other are necessarily in both surfaces and therefore in their line of intersection.
Pass the auxiliary planes in such a way as not only to cut from the surfaces the simplest lines but also in such a way as to make the work of construction as simple as possible.
If the two surfaces are of revolution, with intersecting axes, it will often be found convenient to pass a series of auxiliary cutting spheres with centers at the intersection of the axes. A sphere of this character will cut from the two surfaces circumferences of circles which, lying on the surface of the sphere, will as a rule intersect. These points of intersection must lie on the line in which the given surfaces intersect, since they are common to both surfaces.
cone and parallel to the axis of the cylinder.
Construction. Let the cylinder be represented with its base on H, and let the cone be represented with its base on F, as shown in Fig. 159. The axis of the cylinder is represented by A-B and the axis of the cone is represented by C-D.
axis of the cylinder will be common to all the auxiliary planes.
Through D draw D-E parallel to A-B and produce it to meet IT at Cf and to meet V at f. The horizontal traces of all the auxiliary planes must pass through e^ and the vertical traces of all the auxiliary planes must pass through f.
Through e^ draw any horizontal trace, as S-s^^ cutting the base of the cylinder. Through >S' and /' draw the vertical trace S-s\ S is one of the auxiliary planes and cuts the cylinder in two elements, G—K—L and M—N-0 ; and cuts the cone in two elements, P-D and Q-D.
The element G-K-L of the cylinder crosses the two elements of the cone at K and i, two points of the required curve of intersection. The element M—N-0 of the cylinder crosses the two elements of the cone at ^Y and 0, tAvo more points of the curve.
obtain any number of points on the required curve of intersection.
If it is desired to obtain a point of the curve upon any particular element of the cylinder or of the cone, we have but to draw the traces of the auxiliary plane through the points in which this element pierces the corresponding planes of projection.
It will be noticed that since the horizontal and vertical projections of the curve of intersection are found independently, the accuracy of the work may be tested by noting whether the horizontal and vertical projections of the several points of the curve lie in straight lines perpendicular to G-L.
When projecting on 7/, that portion of the curve which lies upon the upper surface of the cylinder and also upon the upper surface of the cone, and between extreme elements, will be visible and should be so represented.
When projecting on F, that portion of the curve which lies upon the front surface of the cylinder and also upon the front surface of the cone, and between extreme elements, will be visible and should be so represented.
at a given point.
Analysis. Since the curve of intersection lies upon both surfaces, the required tangent must lie both in a plane tangent to the cone at the given point, and in a plane tangent to the cylinder at the same point. Therefore draw two planes, one tangent to the cylinder and the other tangent to the cone at the given point. The intersection of these two planes is the required tangent.
The surface of the cylinder and the curve which lies upon it may be developed by methods previously given (see Section 377). The surface of the cone and the same curve which also lies upon this surface may be developed by the method given in Section 421, yet to be explained.
two cylinders.
Construction. Let the two cylinders be represented with their two bases on H, as shown in Fig. 160. The axis of one cylinder is represented by A-B, and the axis of the other cylinder is represented by C-D,
other auxiliary planes.
Through any point on the axis (7-i>, as i), draw D-E parallel to the other axis A-B. C-D pierces H at c^ and D-E pierces H at e,. S-c-e-Sf is the horizontal trace of an auxiliary plane, and one to which all the other auxiliary planes must be parallel.
The plane S cuts the cylinder whose axis is A-B in two elements, F-G and K-L, and cuts the other cylinder in two elements, jyr-A^and 0-G, These elements cross in the points iV", G, i, and P, four points in the required curve of intersection.
intersection.
If it is desired to determine a point upon any particular element of either cylinder, we have but to pass the auxiliary plane so as to cut from the cylinder this element.
When projecting on ff^ that portion of the curve of intersection which lies on the upper surfaces of both cylinders and between extreme elements will be visible.
When projecting on F, that portion of the curve of intersection which lies on the front surfaces of both cylinders and between extreme elements will be visible.
Analysis. See Problem 275, Case 2. The required tangent will be the intersection of two planes, — one tangent to one cylinder at the point in question, and the other tangent to the other cylinder at the same point. Therefore draw two planes under these conditions and find their line of intersection.
The surfaces of the cylinders and the curves of intersection which are common to both surfaces may be developed by rules previously given (see Problem 253, Case 4).
Analysis. Draw the auxiliary planes through the two vertices.
Construction. See Fig. 161. Let A-B represent the axis of the first cone, which is right circular with base parallel to H-, and let C-D represent the axis of the second cone, whose base is a circle with its plane perpendicular to V. The vertical trace of the plane of the base of the second cone is S-s\ and the intersection of this plane with the plane of the base of the first cone is the line U-G- W.
A straight line through the two vertices will be common to all the auxiliary planes. Therefore through the two vertices draw B-D and produce it to meet the plane of the base of the first cone at E^ a point common to all the lines cut from this plane by the auxiliary planes. This line B-D pierces S, the plane of the base of the second cone, in F^ a point common to all the lines cut from *S^ by the auxiliary planes.
The same auxiliary plane intersects the plane S in the line F-G^ which must cross the base of the second cone in points of the elements cut from the second cone by this auxiliary plane.
To find these elements, revolve S about S-s' into V. The center of the circular base of the second cone will fall at c^, the point F will fall at /^, and the point G will fall at g^.
The line /^-^^-m^ represents the revolved position of F-G^ and the points n^' and rrJ^ represent the revolved positions of the two points in which F-G crosses the base of the second cone.
After the counter revolution M and N will take the positions (mp m') and (ti^ n') respectively, where m, and n, are at the same distances from G-L as M and N respectively are from the axis of revolution S-s'.
The two elements cut from the second cone by this auxiliary plane are then D-M and D-N. These elements cross the tw^o elements cut from the first cone by this same plane at 0, P, Q^ and B^ four points of the required curve of intersection.
Other auxiliary planes may be drawn in the same way, and a sufficient number of points may be determined to locate the required curve of intersection.
That which has been said in previous sections regarding the determination of visible and invisible portions of the curve of intersection, the construction of rectilinear tangents to this curve, and the development of the surfaces, may be said of these surfaces also.
408. To determine in advance the Nature of the Curves in which Cylinders and Cones intersect. The nature of the curve of intersection will depend upon the relative size and position of the intersecting surfaces. The surfaces may intersect so that a portion of one will remain entirely outside of the other, giving one continuous curve of intersection, as in Fig. 159; or they may intersect so as to have one distinct curve of ingress and another distinct curve of egress, as in Fig. 160; or the two surfaces may lie between two planes to which the surfaces are both tangent, in which case the curve of ingress will be tangent to the curve of egress on opposite sides of the surfaces, as in Fig. 161.
The nature of the curve of intersection may be determined in advance by drawing, under the same conditions as the auxiliary planes are drawn, tangent planes to the surfaces.
If in Fig. 159 we draw, as one of the auxiliary planes of this problem, the plane T tangent to the cylinder along the upper surface, the position of its vertical trace T-t' shows that such a plane intersects the cone, and that a portion of the cone remains entirely outside the cylinder.
The plane W drawn under the conditions mentioned above and tangent to the cylinder along the under surface does not cut the cone, showing that a portion of the cylinder remains outside the cone.
uous curve, as shown in the figure.
If both the planes T and W had intersected the cone, the indication would be that the cylinder passed through the cone, giving two distinct curves of intersection.
If the base of the cone had fallen wholly within the two vertical traces T-t' and W-w', the indication would be that the cone passed through the cylinder, giving two distinct curves of intersection.
This last condition is illustrated in Fig. 160, where the cylinder whose axis is C-D intersects the cylinder whose axis is A-B in two distinct curves. The base of the cylinder whose axis is C-D falls wholly within the two planes T and U, which are drawn under the same conditions as the auxiliary planes of this problem, and tangent to the cylinder whose axis is A-B.
If the two vertical traces T-t' and W-w' in Fig. 159 had included and had been tangent to the base of the cone, the indication would be that the two surfaces were included by the tangent planes bringing the curves of intersection into a position of tangency. This condition is illustrated in Fig. 161, where the first cone whose axis is A-B intersects the second cone in two tangent curves. In Fig. 161 the two planes whose intersections with the plane of the base of the first cone are U-U and U-JV are tangent to the first cone and are also tangent to the second cone, as may be seen from the revolved position of the lines in which these tangent planes intersect S, the plane of the base of the second cone.
diameters, one horizontal and the other vertical, axes not intersecting.
415. Problem 284. Fi7id the intersection of two cylinders of unequal diameters, the larger vertical, the smaller inclined at an angle of 60 degrees to H, axes intersecting.
Construction. In Fig. 162 let C represent the center of the sphere and let A-B, passing through the center of the sphere, represent the axis of the cylinder.
Pass the auxiliary planes parallel to A-B and perpendicular to H. The horizontal trace of the auxiliary plane containing the axis is S-Sj. This plane cuts the sphere in a great circle and cuts the cylinder in two elements which intersect the circumference of the circle in four points of the required curve of intersection.
To find these points, revolve the plane S about S-s, into H. C will fall at Cjj and the great circle will fall at Cjj-gjj-ljj-kjj. The axis A-B will fall at a-bjj, and the two elements in which the auxiliary plane intersects the cylinder will fall at d-e^j and f-g^^
Since the auxiliary planes U and W, which are drawn tangent to the cylinder, both intersect the sphere, there are, according to Section 408, two distinct curves of intersection, as may be seen from the drawing.
The rectilinear tangent to the curve at any given point will be the intersection of two planes, one tangent to the cylinder at the given point and the other tangent to the sphere at the same point.
center of the sphere.
419. Problem 288. Find the intersection of a sphere and a cylinder when the axis of the cylinder does not pass through the center of the sphere, and when some of the elements of the cylinder remain wholly outside the sphere.
Casp: 1. To find the intersection.
Analysis 1. Pass the auxiliary planes through the vertex of the cone and perpendicular to //, cutting elements from the cone and semicircles from the hemisphere.
in a semicircle.
To find the points in which these elements intersect the semicircle, revolve >S^ about a vertical axis through B until it is parallel to V. The two elements B-E and B-B will then be vertically projected at h'-r" and h'-p" respectively, and the vertical projection of the semicircle will be coincident with the vertical projection of the hemisphere. Therefore u" and q" are the vertical projections of the revolved positions of two points of the required curve of intersection.
whose vertical projection coincides with the vertical projection of the hemisphere. This plane will locate the points of the curve whose vertical projections fall on the vertical projection of the hemisphere.
A rectilinear tangent to the curve of intersection at any point will be the intersection of two planes, one of which is tangent to the hemisphere at the given point and the other tangent to the cone at the same point.
421. Problem 290. To develop an oblique cone.
Analysis. The intersection of the surface of any cone by the surface of a sphere whose center is at the vertex of the cone is a curve whose points are all equidistant from 'the vertex of the cone, because the curve lies on the surface of the sphere as well as on the surface of the cone.
For this reason, in the development of the cone, this particular curve of intersection will roll out into the arc of a circle whose center is the vertex of the cone and whose radius is equal to the radius of the sphere.
If upon this arc, starting from any point, we lay off successively the actual arc distances between the points in which the elements of the cone cut the curve of intersection before development, and if we connect these points of division and the center of the arc by straight lines, these straight lines will represent the elements of the cone in development.
To determine the positions in development of the points on this curve through which the various elements of the cone pass before development, we must determine the actual distances between these points measured along the curve before development.
the elements of the cylinder, the curve of the base will roll out into a straight line to which the elements of the cylinder will remain perpendicular (see Problem 249, Case 4).
division on this curve are now revealed.
Returning now to Fig. 164, start with F'^\, any point on the arc, and make the distances F''-0'\ 0''-Q'\ Q'^-G'\ etc., such that their rectified lengths shall be equal respectively to the rectified distances F-0, 0-Q, Q-G, etc., of Fig. 165. Through B'' and the points just determined draw B''-F'^-D'\ B'^-(y^-N'\ etc., to represent in development the elements of the cone passing through the points F^ O, Q, etc., of Fig. 163.
Let it now be required to develop the curve of the base of the cone. In Fig. 164 make B''-iy\ B'-N\ B''~P'\ etc., equal respectively to B-D, B-N, B-P, etc., of the original cone, Fig. 163. The curve D'^-N'^-P'^-B'^-D'j represents the curve of the base of the cone in development. In the same way we may find the development of any curve on the surface of the cone.
422. Problem 291. Find the intersection of a sphere hy a cone when the axis of the cone contains the center of the sphere, and when the vertex of the cone is outside the surface of the sphere.
423. Problem 292. Find the inter sectioyi of a sphere mid a cone when the vertex of the cone lies outside the surface of the sphere, and when some of the elements of the cone lie wholly/ outside the sphere.
424. Problem 293. Given a sphere and a point without the surface; required to determine a cone tvith vertex at the point and with surface tangent to the sphere, and to determine the circle of tangency between the two surfaces.
be required to find the
intersection of an inverted right circular cone by a right circular cylinder, as represented in Fig. 166. A-B represents the axis of the cone and D-E represents the axis of the cylinder, the two axes intersecting at D and lying in a plane parallel to V.
An auxiliary sphere with center at B and with radius equal to ^^-f will cut the surface of the cone in the circumference of a circle whose vertical projection is f-g^ and whose horizontal projection i^f-m-g-Uj. The same sphere will cut the surface of the cylinder in the circumference of another circle whose vertical projection is h'-V. The circumferences of these two circles intersect in two points vertically projected at (m', 71') and horizontally projected at nij and n^ respectively. M and N are two points of the required curve of intersection, and others may be found in the same way.
The meridian plane of the axes will cut the cone and the cylinder in those elements which, when projecting upon F, appear as extreme elements. These elements intersect at 0 and P respectively, the lowest and the highest points of the curve of intersection.
When projecting on i/, if we regard the inverted cone as hollow, that portion of the curve of intersection lying on the upper surface of the cylinder will be visible.
The rectilinear tangent to the curve of intersection at any point will be the intersection of two planes, one tangent to the cone at the given point and the other tangent to the cylinder at the same point.
By use of methods already explained we may develop both of the given surfaces and show the character of the curve of intersection when rolled out into a plane surface.
429. Introductory Statements. In making a working drawing of a solid it is customary to place the object in such a position that the plane of two of its dimension lines is parallel to the plane of projection. This results in the representation of only one face of the object at a time.
It is sometimes desirable, however, to show three dimension faces of a solid in one view, and without going to the trouble of making a perspective drawing. This is accomplished by isometric projection.
0-Z represent the three edges of a right trihedral angle with vertex at 0. Through the vertex 0 draw a straight line P—O-o' equally inclined to the three edges. Through any point o' on P-O-o' pass a plane F perpendicular to P-0-o\ and project the three edges of the right trihedral angle upon this plane. Since the edges themselves are equally inclined to the line P-0-o\ and therefore equally inclined to the plane F, and since they form the three edges of a right trihedral angle, the three projections o -a;', o^-y\ and o^-z^ will radiate from o^ so as to form angles of 120 degrees.
The lines 0-X^ 0-Y, and 0-Z are called coordinate axes. The plane Fis called the isometric plane of projection ; the point o\ the projection of 0, is called the isometric origin; and the lines o'-x', o'-y\ and o'-z', which are the projections upon the plane F of the original axes 0-X, O-Y, and 0-Z, are called the isometric axes.
The planes determined by the lines 0-X and 0-F, 0-Y and 0-Z^ and 0-Z and 0-X are called coordinate plafies^ and the projections of magnitudes lying on these planes between the limiting axes will fall between the projections of these limiting axes.
The axis 0-Y is given a position directly beneath the line P-0. As a result the isometric axis o'-«/' has a vertical position, the axis o'-x' makes an angle of 30 degrees with a horizontal line on the right, and the axis o'-z' makes an angle of 30 degrees with a horizontal line on the left. For this reason the isometric axes and all straight lines parallel to them are easily represented upon the drawing board by use of the T-square and the 30-degree triangle.
Each of the three dimensions — length, breadth, and thickness — of a solid are measured on straight lines perpendicular to the plane of the other two, corresponding with the three edges of a right trihedral angle.
It is therefore possible to place a solid in such a position that its three principal dimension lines shall coincide with the three coordinate axes 0-X^ 0-T, and 0-Z of Fig. 167. When the magnitude occupies this position its projection upon the plane V will reveal the characteristics of three dimension faces of the object, and the projection is called isometric.
Whenever a solid is projected upon a plane to which its principal dimension lines are equally inclined, the projection is called isometric, since on account of this equality of inclination the projections of equal distances measured upon these dimension lines, or upon lines parallel to them, will be equal.
The projection of any magnitude may be said to be isometric whenever this projection is determined by reference to isometric axes which themselves are the isometric projections of the three coordinate axes to which the magnitude is referred, coordinates with reference to the isometric axes appearing as the isometric projections of the corresponding coordinates used in connection with the original coordinate axes.
430. The Isometric Scale. The inclination of each of the three coordinate axes 0-X, 0-Y^ and 0-Z to the plane of projection is 35°. 16'. By trigonometry the isometric projection of one foot
If this length is divided into twelve equal parts, each one of these divisions will represent the isometric projection of an inch measured under the conditions mentioned above. In the same way we may subdivide the inch and thus establish an- isometric scale by which we may determine the length in isometric projection of any distance measured upon the coordinate axes or upon any lines parallel to these axes.
Since drawings are usually made either on a smaller or a larger scale than tlie object represented, and since on account of the equal inclination of the coordinate axes to the plane of projection, the projections of distances measured along these lines are equally foreshortened, there is no good reason why any other than the ordinary foot scale should be used in connection with this form of projection. The isometric scale is therefore not used in practical drafting.
431. Shade Lines. In isometric projection the rays of light are assumed parallel to the plane • of projection and inclined at an angle of 30 degrees with the horizon. With these exceptions, shade lines in isometric projection are determined and represented precisely as in orthographic projection.
If the cube to whose diagonal rays of light in orthographic projection have been referred (see Section 230) is so placed that the diagonal passing through the upper right-hand front vertex of the cube is perpendicular to F, and so that the right-hand vertical edge of the cube is still in a vertical plane, the diagonal passing through the upper left-hand front vertex of the cube in its first position — the diagonal to which rays of light in orthographic projection were referred — will in the new position be parallel to V and make an angle of 30 degrees with H,
In isometric projection, then, rays of light may be referred to the same diagonal of the cube as in orthographic projection, provided the cube occupies the position indicated above.
432. General Instructions in regard to Solution of Problems. The isometric projection of a point whose coordinates with reference to two coordinate axes are known is the intersection of the isometric projections of the two coordinate lines of the point.
The isometric projection of a point whose coordinates with reference to three coordinate planes are known is the intersection of the isometric projections of the three coordinate lines of the point.
The isometric projection of a straight line is the straight line determined by the isometric projections of two points of the given line. Since the orthographic projections of parallel lines are parallel, the isometric projections of parallel lines will be parallel whether the lines themselves are parallel to the coordinate axes or not.
by the isometric projections of the points which determine the line.
The isometric projection of a surface determined or limited by lines, straight or curved, is that surface determined by the isometric projections of the determining or limiting lines.
To draw the isometric projection of a magnitude of three dimensions, place the magnitude in such a position that its three principal dimension lines shall be either coincident with or parallel to the three coordinate axes 0-X, 0- F, and 0-Z ; then the isome1> ric projections of the principal dimension lines of the magnitude will be either coincident with or parallel to the isometric axes.
coordinates with reference to two rectangular axes are known.
In Fig. 168 let o'-x\ o'-y\ and o'-z' represent the isometric axes. Place the two rectangular axes to which the point is referred in coincidence with 0-X and 0-Z respectively. Then o'-x' and 0 -z' are the isometric projections of the rectangular axes.
ISOMETRIC PROJECTION
Of course the same result will be obtained if after drawing the line a'-d' we lay off upon it the remaining coordinate a'-d' equal to o'-h'. The axes to which the point is referred may be assumed in coincidence with 0-X and 0- F, or in coincidence with 0-Z and 0- Y.
434. Problem 299. To find the
isometric projection of a point whose coordinates with reference to three rectangular coordinate planes are known.
represent the isometric axes.
Place the three coordinate axes, to whose planes the point is referred, in coincidence with 0-X, 0-F, and 0-Z respectively. Then o'-x'^ o'-i/\ and o'-z' are the isometric projections of the coordinate axes.
Make o'-a' equal to the distance of the point from the plane ^-0- rand through a' draw a'-b' parallel to o'-z'. Make a'-b' equal to the distance of the point from the plane X-O-Y, and through b' draw b'-d^ parallel to o'-y'. Make b'-d' equal to the distance of
the point from the plane Z-O-X, The point d' is the isometric projection of the point in question.
The lines e'-d', d'-f, and b'-d' are the isometric projections of the three coordinate lines of the point D.
isometric projection of a straight line when the coordiiiates of two of its points with reference to three rectangular coordinate planes are known.
In Fig. 170 let o'-x', o'-y\ and o'-z' represent the isometric axes. Place the coordinate axes to whose planes the line is referred in coincidence with 0-X, 0- F, and 0-Z. Then o'-x^, o'-y', and o'-z' are the isometric projections of these coordinate axes.
437. Problem 302. To find the isometric projection of a triangular card when the coordinates of its three vertices with reference to three rectangular coordinate planes are known.
metric projections of the three vertices Jf, iV, and F. The triangle m'—n'—p' is the projection sought.
438. Problem 303. To make an
isometric projection of a cube. I See Fig. 173. Let o'-x', o'-y', and o'-z' represent the isometric axes. Place the cube so that one of its vertices shall coincide with the origin of coordinates, 0, and so that its three adjacent edges shall coincide with the three coordinate axes 0-X, 0-Y, and 0-Z.
The isometric projections of these three edges will fall on the isometric axes, and the isometric projections of the remaining edges will be parallel to these three axes.
Make o'-a' and o'-d! each equal to the edge of the cube. Through a' draw a'-e' parallel to o'-d'. Through d' draw d'-e' parallel to o'-a' and intersecting a'-e' at e'. The figure o'-a'-e'-d' represents the isometric projection of the upper face of the cube.
Make o'-h' equal to the edge of the cube. Through a' draw a'-f parallel to o'-h'. Through h' draw h'-f parallel to o'-a' and intersecting a'-f at /'. The figure o'-a'-f'-b' represents the isometric projection of the right-hand face of the cube.
to o'-d'. Through d' draw d'-g' parallel to o'-h' and intersecting h'-g' at g'. The figure o'-h'-g'-d' represents the isometric projection of the left-hand face of the cube.
G-E will be in the light, and the three remaining faces will be in the dark. Therefore the visible shade lines are G-B^ B-0^ 0-A,
See Fig. 174. Place the upper
front vertex of the pedestal at the origin 0. Make o'-a^ and o'-h' each equal to the side of the square pedestal ; also make o'-d' equal to the altitude of the pedestal. The pedestal is now completed by drawing through a', b', and d' straight lines parallel to the proper axes.
Knowing the relation of the horizontal dimensions of the pillar to the horizontal dimensions of the pedestal, we can determine the distance between the corresponding faces of the pillar and pedestal. Make o'-e' equal to the distance between the left-hand face of the pillar and the left-hand face of the pedestal, and through e' draw e'-f-k' parallel to o'-z'. Make e'-f equal to the distance between the right-hand face of the pillar and the right-hand face of the pedestal, and through /' draw f'-g' parallel to o'-x' . Make f'-k'
prism to be inscribed within a rectangular prism whose rectangular bases circumscribe the hexagonal bases of the given prism, and whose altitude is equal to that of the given prism.
rectangle of this base.
The isometric projection of the circumscribing prism is represented in Fig. 175 by o' -a^ -e^ -d' -h\ where o'-a' and o'-d' are equal respectively to the horizontal dimensions of this prism, and where o'-h' is equal to the altitude of the prism.
To draw the isometric projection of the upper base of the hexagonal prism, make o'-Z', o'—m\ d'-n\ etc., of Fig. 175 equal respectively to 0-X, 0-M^ D-N^ etc., of Fig. 176, and connect the points thus found by straight lines.
To complete the projection of the prism, find the isometric projection of the lower base by the process just explained and connect the corresponding vertices of the two bases.
of the frustum.
Construction. See Figs. 177 and 178. Fig. 178 represents in plan the two bases of the frustum and their circumscribing squares. B-G-K-F represents the circumscribing square of the larger base
The isometric projection of the circumscribing prism is represented in Fig. 177 by o' -a' -e' -d' -h' , where o'-a' and o'-d' are each made equal to the side of the circumscribing square of the larger base of the frustum, and where o'-U is made equal to the altitude of the frustum.
The isometric projection of the lower base of the frustum is represented in Fig. 177 by V -m' -'nJ -p' - • • •, where h'-V^ h'-7n\ b'-n'-, etc., are made equal respectively to i?-Z, B-M, B-N^ etc., of Fig. 178.
The isometric projection of the circumscribing square of the upper base of the frustum is represented in Fig. 177 by q'-r'-ii'-w\ concentric with o'-d'-e'-a' and having its side equal to the side of the square Q-B-U-W oi Fig. 178.
ously explained.
The isometric projection of the edges of the frustum may now be represented by connecting the vertices of the upper base with the corresponding vertices of the lower base.
The point F^ for example, one apex of the lid, is at the distance F-g above the horizontal plane and at the distance F-k back of the vertical plane. The point F is also in the plane of the left-hand end of the box, and in isometric projection will be located with reference to the isometric axes o'-z' and o'-y' .
vertical plane.
In Fig. 179 make d'-q' and q'-p' equal respectively to D-q and q-P of Fig. 180, locating p' . Through p\ which is the isometric projection of P, draw p'-s' parallel to o'-x'^ to represent the inner horizontal edge of the lid.
by tracing the required curve through these projections.
If the curve is of single curvature, locate, by reference to two rectangular axes, a sufficient number of points on the curve to determine the curve accurately. Find the isometric projections of the rectangular axes and then by use of the known coordinate distances determine the isometric projections of the points which locate the curve.
445. Problem 309. To make an isometric drawing of a circle. See Figs. 182 and 183. Fig. 183 represents the circle referred to the four sides of a circumscribing square A-B-C-D, any two of whose adjacent sides may be taken as rectangular axes of reference. The coordinates of a number of points, E, Z, F, M, G, iV, JT, P, on the circumference, including the points of tangency, are here determined.
Fig. 182 shows the isometric projection of the circle in three positions. First, when the isometric projections of the axes A—B and A-D coincide with the isometric axes o'-x' and o'-z' respectively. Second, when the isometric projections of the axes D-C and D-A
coincide with the isometric axes o'-x' and o'-y' respectively. Third, when the isometric projections of the axes C-D and C-B coincide with the isometric axes o'-z' and o'-y' respectively.
In each case the isometric projections of the points are found by use of the coordinate measurements made in Fig. 183. For example, the point p\ Fig. 182, is obtained by making o'-w' and w'-p' equal respectively to ^-/^Fand W-P of Fig. 183.
curve.
See Figs. 184 and 185. Let Fig. 185 represent the curve when referred to two rectangular axes, one of which is 0-A tangent to the curve at D and the other 0-B tangent to the curve at F,
the curve are determined with reference to these axes.
The isometric projection of this curve is shown in Fig. 184, where the isometric projections of the axes 0-A and 0-B coincide with the isometric axes o'-y' and o'-x' respectively, and where the isometric projections of the points W, B, Z>, etc., are found as previously explained.
We may draw the isometric projection of this curve when the curve occupies any desired position with reference to the coordinate axes 0-X, 0- Y, and 0-Z, whether in the plane determined by any two of these axes or in the space-angle determined by the three axes.
The isometric axis o'-x' represents the isometric projection of G-L^ o'-z' represents the isometric projection of P-pp and o'-y' represents the isometric projection of P-p'.
In Fig. 186 make o'-w' equal to the distance of Jf from the plane P, and through w' draw w'-r' parallel to o'-z'. Make w'-r' equal to the distance of M from F, and through r' draw r^-m' parallel to o'-i/'. Make r'-m' equal to the distance of M from H. The point m' is the isometric projection of Jf, and other points may be found in the same way.
448. Oblique Projection. In orthographic and in isometric projection the observer is assumed at an infinite distance from the plane of projection, and the resultant parallel projecting lines are taken perpendicular to the plane of projection.
tion, the system of projection is called oblique projection,
449. Cavalier Perspective or Cabinet Projection. When the projecting lines are assumed parallel to each other and at an inclination of 45 degrees to the plane of projection, the system of projection is called cavalier perspective or cabinet projection.
In Fig. 188 let a'-B represent a straight line perpendicular to V and piercing it at a'. Through B draw a projecting line B-b' at an inclination of 45 degrees to Tand piercing Fat 5'. The line a'-b' is the cabinet projection of a'-B,
No restriction whatever is made upon the direction which the projecting lines shall take so long as they are inclined at an angle of 45 degrees with the plane of projection. In any given problem, however, the projecting lines must be parallel.
450. Observations. Since the projecting lines are inclined 45 degrees to the plane of projection, the cabinet projection of a straight line perpendicular to the plane of projection will be equal to the line itself.
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dbByyAtzbbpUMUSB | Human Biology | 24 Chapter 44: Ecology and the Biosphere
44 | ECOLOGY AND THE BIOSPHERE
Figure 44.1 The (a) deer tick carries the bacterium that produces Lyme disease in humans, often evident in (b) a symptomatic bull’s eye rash. The (c) white-footed mouse is one well-known host to deer ticks carrying the Lyme disease bacterium. (credit a: modification of work by Scott Bauer, USDA ARS; credit b: modification of work by James Gathany, CDC; credit c: modification of work by Rob Ireton)
Introduction
Why study ecology? Perhaps you are interested in learning about the natural world and how living things have adapted to the physical conditions of their environment. Or, perhaps you’re a future physician seeking to understand the connection between human health and ecology.
Humans are a part of the ecological landscape, and human health is one important part of human interaction with our physical and living environment. Lyme disease, for instance, serves as one modern-day example of the connection between our health and the natural world (Figure 44.1). More formally known as Lyme borreliosis, Lyme disease is a bacterial infection that can be transmitted to humans when they are bitten by the deer tick (Ixodes scapularis), which is the primary vector for this disease. However, not all deer ticks carry the bacteria that will cause Lyme disease in humans, and I. scapularis can have other hosts besides deer. In fact, it turns out that the probability of infection depends on the type of host upon which the tick develops: a higher proportion of ticks that live on white-footed mice carry the bacterium than do ticks that live on deer. Knowledge about the environments and population densities in which the host species is abundant would help a physician or an epidemiologist better understand how Lyme disease is transmitted and how its incidence could be reduced.
44.1 | The Scope of Ecology
Ecology is the study of the interactions of living organisms with their environment. One core goal of ecology is to understand the distribution and abundance of living things in the physical environment. Attainment of this goal requires the integration of scientific disciplines inside and outside of biology, such as biochemistry, physiology, evolution, biodiversity, molecular biology, geology, and climatology. Some ecological research also applies aspects of chemistry and physics, and it frequently uses mathematical models.
Climate change can alter where organisms live, which can sometimes directly affect human health. Watch the PBS video “Feeling the Effects of Climate Change” (http://openstaxcollege.org/l/climate_health) in which researchers discover a pathogenic organism living far outside of its normal range.
Levels of Ecological Study
When a discipline such as biology is studied, it is often helpful to subdivide it into smaller, related areas. For instance, cell biologists interested in cell signaling need to understand the chemistry of the signal molecules (which are usually proteins) as well as the result of cell signaling. Ecologists interested in the factors that influence the survival of an endangered species might use mathematical models to predict how current conservation efforts affect endangered organisms. To produce a sound set of management options, a conservation biologist needs to collect accurate data, including current population size, factors affecting reproduction (like physiology and behavior), habitat requirements (such as plants and soils), and potential human influences on the endangered population and its habitat (which might be derived through studies in sociology and urban ecology). Within the discipline of ecology, researchers work at four specific levels, sometimes discretely and sometimes with overlap: organism, population, community, and ecosystem (Figure 44.2).
Figure 44.2 Ecologists study within several biological levels of organization. (credit “organisms”: modification of work by “Crystl”/Flickr; credit “ecosystems”: modification of work by Tom Carlisle, US Fish and Wildlife Service Headquarters; credit “biosphere”: NASA)
Organismal Ecology
Researchers studying ecology at the organismal level are interested in the adaptations that enable individuals to live in specific habitats. These adaptations can be morphological, physiological, and behavioral. For instance, the Karner blue butterfly (Lycaeides melissa samuelis) (Figure 44.3) is considered a specialist because the females preferentially oviposit (that is, lay eggs) on wild lupine. This preferential adaptation means that the Karner blue butterfly is highly dependent on the presence of wild lupine plants for its continued survival
Figure 44.3 The Karner blue butterfly (Lycaeides melissa samuelis) is a rare butterfly that lives only in open areas with few trees or shrubs, such as pine barrens and oak savannas. It can only lay its eggs on lupine plants. (credit: modification of work by J & K Hollingsworth, USFWS)After hatching, the larval caterpillars emerge and spend four to six weeks feeding solely on wild lupine (Figure 44.4). The caterpillars pupate (undergo metamorphosis) and emerge as butterflies after about four weeks. The adult butterflies feed on the nectar of flowers of wild lupine and other plant species. A researcher interested in studying Karner blue butterflies at the organismal level might, in addition to asking questions about egg laying, ask questions about the butterflies’ preferred temperature (a physiological question) or the behavior of the caterpillars when they are at different larval stages (a behavioral question).
Figure 44.4 The wild lupine (Lupinus perennis) is the host plant for the Karner blue butterfly.
Population Ecology
A population is a group of interbreeding organisms that are members of the same species living in the same area at the same time. (Organisms that are all members of the same species are called conspecifics.) A population is identified, in part, by where it lives, and its area of population may have natural or artificial boundaries: natural boundaries might be rivers, mountains, or deserts, while examples of artificial boundaries include mowed grass, manmade structures, or roads. The study of population ecology focuses on the number of individuals in an area and how and why population size changes over time. Population ecologists are particularly interested in counting the Karner blue butterfly, for example, because it is classified as federally endangered. However, the distribution and density of this species is highly influenced by the distribution and abundance of wild lupine. Researchers might ask questions about the factors leading to the decline of wild lupine and how these affect Karner blue butterflies. For example, ecologists know that wild lupine thrives in open areas where trees and shrubs are largely absent. In natural settings, intermittent wildfires regularly remove trees and shrubs, helping to maintain the open areas that wild lupine requires. Mathematical models can be used to understand how wildfire suppression by humans has led to the decline of this important plant for the Karner blue butterfly.
Community Ecology
For example, Karner blue butterfly larvae form mutualistic relationships with ants. Mutualism is a form of a long-term relationship that has coevolved between two species and from which each species benefits. For mutualism to exist between individual organisms, each species must receive some benefit from the other as a consequence of the relationship. Researchers have shown that there is an increase in the probability of survival when Karner blue butterfly larvae (caterpillars) are tended by ants. This might be because the larvae spend less time in each life stage when tended by ants, which provides an advantage for the larvae. Meanwhile, the Karner blue butterfly larvae secrete a carbohydrate-rich substance that is an important energy source for the ants. Both the Karner blue larvae and the ants benefit from their interaction.
Ecosystem Ecology
Ecosystem ecology is an extension of organismal, population, and community ecology. The ecosystem is composed of all the biotic components (living things) in an area along with the abiotic components (non-living things) of that area. Some of the abiotic components include air, water, and soil. Ecosystem biologists ask questions about how nutrients and energy are stored and how they move among organisms and the surrounding atmosphere, soil, and water.
The Karner blue butterflies and the wild lupine live in an oak-pine barren habitat. This habitat is characterized by natural disturbance and nutrient-poor soils that are low in nitrogen. The availability of nutrients is an important factor in the distribution of the plants that live in this habitat. Researchers interested in ecosystem ecology could ask questions about the importance of limited resources and the movement of resources, such as nutrients, though the biotic and abiotic portions of the ecosystem.
Visit this site (http://openstaxcollege.org/l/ecologist_role) to see Stephen Wing, a marine ecologist from the University of Otago, discuss the role of an ecologist and the types of issues ecologists explore.
44.2 | Biogeography
Many forces influence the communities of living organisms present in different parts of the biosphere (all of the parts of Earth inhabited by life). The biosphere extends into the atmosphere (several kilometers above Earth) and into the depths of the oceans. Despite its apparent vastness to an individual human, the biosphere occupies only a minute space when compared to the known universe. Many abiotic forces influence where life can exist and the types of organisms found in different parts of the biosphere. The abiotic factors influence the distribution of biomes: large areas of land with similar climate, flora, and fauna.
Biogeography
Biogeography is the study of the geographic distribution of living things and the abiotic factors that affect their distribution. Abiotic factors such as temperature and rainfall vary based mainly on latitude and elevation. As these abiotic factors change, the composition of plant and animal communities also changes. For example, if you were to begin a journey at the equator and walk north, you would notice gradual changes in plant communities. At the beginning of your journey, you would see tropical wet forests with broad-leaved evergreen trees, which are characteristic of plant communities found near the equator. As you continued to travel north, you would see these broad-leaved evergreen plants eventually give rise to seasonally dry forests with scattered trees. You would also begin to notice changes in temperature and moisture. At about 30 degrees north, these forests would give way to deserts, which are characterized by low precipitation.
Species distribution patterns are based on biotic and abiotic factors and their influences during the very long periods of time required for species evolution; therefore, early studies of biogeography were closely linked to the emergence of evolutionary thinking in the eighteenth century. Some of the most distinctive assemblages of plants and animals occur in regions that have been physically separated for millions of years by geographic barriers. Biologists estimate that Australia, for example, has between 600,000 and 700,000 species of plants and animals. Approximately 3/4 of living plant and mammal species are endemic species found solely in Australia (Figure 44.6ab).
Figure 44.6 Australia is home to many endemic species. The (a) wallaby (Wallabia bicolor), a medium-sized member of the kangaroo family, is a pouched mammal, or marsupial. The (b) echidna (Tachyglossus aculeatus) is an egg-laying mammal. (credit a: modification of work by Derrick Coetzee; credit b: modification of work by Allan Whittome)Sometimes ecologists discover unique patterns of species distribution by determining where species are not found. Hawaii, for example, has no native land species of reptiles or amphibians, and has only one native terrestrial mammal, the hoary bat. Most of New Guinea, as another example, lacks placental mammals.
Plants can be endemic or generalists: endemic plants are found only on specific regions of the Earth, while generalists are found on many regions. Isolated land masses—such as Australia, Hawaii, and Madagascar—often have large numbers of endemic plant species. Some of these plants are endangered due to human activity. The forest gardenia (Gardenia brighamii), for instance, is endemic to Hawaii; only an estimated 15–20 trees are thought to exist (Figure 44.7).
Figure 44.7 Listed as federally endangered, the forest gardenia is a small tree with distinctive flowers. It is found only in five of the Hawaiian Islands in small populations consisting of a few individual specimens. (credit: Forest & Kim Starr)
Energy Sources
Energy from the sun is captured by green plants, algae, cyanobacteria, and photosynthetic protists. These organisms convert solar energy into the chemical energy needed by all living things. Light availability can be an important force directly affecting the evolution of adaptations in photosynthesizers. For instance, plants in the understory of a temperate forest are shaded when the trees above them in the canopy completely leaf out in the late spring. Not surprisingly, understory plants have adaptations to successfully capture available light. One such adaptation is the rapid growth of spring ephemeral plants such as the spring beauty (Figure 44.8). These spring flowers achieve much of their growth and finish their life cycle (reproduce) early in the season before the trees in the canopy develop leaves.
Figure 44.8 The spring beauty is an ephemeral spring plant that flowers early in the spring to avoid competing with larger forest trees for sunlight. (credit: John Beetham)
In aquatic ecosystems, the availability of light may be limited because sunlight is absorbed by water, plants, suspended particles, and resident microorganisms. Toward the bottom of a lake, pond, or ocean, there is a zone that light cannot reach. Photosynthesis cannot take place there and, as a result, a number of adaptations have evolved that enable living things to survive without light. For instance, aquatic plants have photosynthetic tissue near the surface of the water; for example, think of the broad, floating leaves of a water lily—water lilies cannot survive without light. In environments such as hydrothermal vents, some bacteria extract energy from inorganic chemicals because there is no light for photosynthesis.
The availability of nutrients in aquatic systems is also an important aspect of energy or photosynthesis. Many organisms sink to the bottom of the ocean when they die in the open water; when this occurs, the energy found in that living organism is sequestered for some time unless ocean upwelling occurs. Ocean upwelling is the rising of deep ocean waters that occurs when prevailing winds blow along surface waters near a coastline (Figure 44.9). As the wind pushes ocean waters offshore, water from the bottom of the ocean moves up to replace this water. As a result, the nutrients once contained in dead organisms become available for reuse by other living organisms.
Figure 44.9 Ocean upwelling is an important process that recycles nutrients and energy in the ocean. As wind (green arrows) pushes offshore, it causes water from the ocean bottom (red arrows) to move to the surface, bringing up nutrients from the ocean depths.
In freshwater systems, the recycling of nutrients occurs in response to air temperature changes. The nutrients at the bottom of lakes are recycled twice each year: in the spring and fall turnover. The spring and fall turnover is a seasonal process that recycles nutrients and oxygen from the bottom of a freshwater ecosystem to the top of a body of water (Figure 44.10). These turnovers are caused by the formation of a thermocline: a layer of water with a temperature that is significantly different from that of the surrounding layers. In wintertime, the surface of lakes found in many northern regions is frozen. However, the water under the ice is slightly warmer, and the water at the bottom of the lake is warmer yet at 4 °C to 5 °C (39.2 °F to 41 °F). Water is densest at 4 °C; therefore, the deepest water is also the densest. The deepest water is oxygen poor because the decomposition of organic material at the bottom of the lake uses up available oxygen that cannot be replaced by means of oxygen diffusion into the water due to the surface ice layer.
In springtime, air temperatures increase and surface ice melts. When the temperature of the surface water begins to reach 4 °C, the water becomes heavier and sinks to the bottom. The water at the bottom of the lake is then displaced by the heavier surface water and, thus, rises to the top. As that water rises to the top, the sediments and nutrients from the lake bottom are brought along with it. During the summer months, the lake water stratifies, or forms layers, with the warmest water at the lake surface.
As air temperatures drop in the fall, the temperature of the lake water cools to 4 °C; therefore, this causes fall turnover as the heavy cold water sinks and displaces the water at the bottom. The oxygen-rich water at the surface of the lake then moves to the bottom of the lake, while the nutrients at the bottom of the lake rise to the surface (Figure 44.10). During the winter, the oxygen at the bottom of the lake is used by decomposers and other organisms requiring oxygen, such as fish.
Temperature
Temperature affects the physiology of living things as well as the density and state of water. Temperature exerts an important influence on living things because few living things can survive at temperatures below 0 °C (32 °F) due to metabolic constraints. It is also rare for living things to survive at temperatures exceeding 45 °C (113 °F); this is a reflection of evolutionary response to typical temperatures. Enzymes are most efficient within a narrow and specific range of temperatures; enzyme degradation can occur at higher temperatures. Therefore, organisms either must maintain an internal temperature or they must inhabit an environment that will keep the body within a temperature range that supports metabolism. Some animals have adapted to enable their bodies to survive significant temperature fluctuations, such as seen in hibernation or reptilian torpor. Similarly, some bacteria are adapted to surviving in extremely hot temperatures such as geysers. Such bacteria are examples of extremophiles: organisms that thrive in extreme environments.
Temperature can limit the distribution of living things. Animals faced with temperature fluctuations may respond with adaptations, such as migration, in order to survive. Migration, the movement from one place to another, is an adaptation found in many animals, including many that inhabit seasonally cold climates. Migration solves problems related to temperature, locating food, and finding a mate. In migration, for instance, the Arctic Tern (Sterna paradisaea) makes a 40,000 km (24,000 mi) round trip flight each year between its feeding grounds in the southern hemisphere and its breeding grounds in the Arctic Ocean. Monarch butterflies (Danaus plexippus) live in the eastern United States in the warmer months and migrate to Mexico and the southern United States in the wintertime. Some species of mammals also make migratory forays. Reindeer (Rangifer tarandus) travel about 5,000 km (3,100 mi) each year to find food. Amphibians and reptiles are more limited in their distribution because they lack migratory ability. Not all animals that can migrate do so: migration carries risk and comes at a high energy cost.
Some animals hibernate or estivate to survive hostile temperatures. Hibernation enables animals to survive cold conditions, and estivation allows animals to survive the hostile conditions of a hot, dry climate. Animals that hibernate or estivate enter a state known as torpor: a condition in which their metabolic rate is significantly lowered. This enables the animal to wait until its environment better supports its survival. Some amphibians, such as the wood frog (Rana sylvatica), have an antifreeze-like chemical in their cells, which retains the cells’ integrity and prevents them from bursting.
Water
Water is required by all living things because it is critical for cellular processes. Since terrestrial organisms lose water to the environment by simple diffusion, they have evolved many adaptations to retain water.
- Plants have a number of interesting features on their leaves, such as leaf hairs and a waxy cuticle, that serve to decrease the rate of water loss via transpiration.
- Freshwater organisms are surrounded by water and are constantly in danger of having water rush into their cells because of osmosis. Many adaptations of organisms living in freshwater environments have evolved to ensure that solute concentrations in their bodies remain within appropriate levels. One such adaptation is the excretion of dilute urine.
- Marine organisms are surrounded by water with a higher solute concentration than the organism and, thus, are in danger of losing water to the environment because of osmosis. These organisms have morphological and physiological adaptations to retain water and release solutes into the environment. For example, Marine iguanas (Amblyrhynchus cristatus), sneeze out water vapor that is high in salt in order to maintain solute concentrations within an acceptable range while swimming in the ocean and eating marine plants.
Inorganic Nutrients and Soil
Inorganic nutrients, such as nitrogen and phosphorus, are important in the distribution and the abundance of living things. Plants obtain these inorganic nutrients from the soil when water moves into the plant through the roots. Therefore, soil structure (particle size of soil components), soil pH, and soil nutrient content play an important role in the distribution of plants. Animals obtain inorganic nutrients from the food they consume. Therefore, animal distributions are related to the distribution of what they eat. In some cases, animals will follow their food resource as it moves through the environment.
Other Aquatic Factors
Some abiotic factors, such as oxygen, are important in aquatic ecosystems as well as terrestrial environments. Terrestrial animals obtain oxygen from the air they breathe. Oxygen availability can be an issue for organisms living at very high elevations, however, where there are fewer molecules of oxygen in the air. In aquatic systems, the concentration of dissolved oxygen is related to water temperature and the speed at which the water moves. Cold water has more dissolved oxygen than warmer water. In addition, salinity, current, and tide can be important abiotic factors in aquatic ecosystems.
Other Terrestrial Factors
Wind can be an important abiotic factor because it influences the rate of evaporation and transpiration. The physical force of wind is also important because it can move soil, water, or other abiotic factors, as well as an ecosystem’s organisms.
Fire is another terrestrial factor that can be an important agent of disturbance in terrestrial ecosystems. Some organisms are adapted to fire and, thus, require the high heat associated with fire to complete a part of their life cycle. For example, the jack pine—a coniferous tree—requires heat from fire for its seed cones to open (Figure 44.11). Through the burning of pine needles, fire adds nitrogen to the soil and limits competition by destroying undergrowth.
Figure 44.11 The mature cones of the jack pine (Pinus banksiana) open only when exposed to high temperatures, such as during a forest fire. A fire is likely to kill most vegetation, so a seedling that germinates after a fire is more likely to receive ample sunlight than one that germinates under normal conditions. (credit: USDA)
Abiotic Factors Influencing Plant Growth
Temperature and moisture are important influences on plant production (primary productivity) and the amount of organic matter available as food (net primary productivity). Net primary productivity is an estimation of all of the organic matter available as food; it is calculated as the total amount of carbon fixed per year minus the amount that is oxidized during cellular respiration. In terrestrial environments, net primary productivity is estimated by measuring the aboveground biomass per unit area, which is the total mass of living plants, excluding roots. This means that a large percentage of plant biomass which exists underground is not included in this measurement. Net primary productivity is an important variable when considering differences in biomes. Very productive biomes have a high level of aboveground biomass.
Annual biomass production is directly related to the abiotic components of the environment. Environments with the greatest amount of biomass have conditions in which photosynthesis, plant growth, and the resulting net primary productivity are optimized. The climate of these areas is warm and wet. Photosynthesis can proceed at a high rate, enzymes can work most efficiently, and stomata can remain open without the risk of excessive transpiration; together, these factors lead to the maximal amount of carbon dioxide (CO2) moving into the plant, resulting in high biomass production. The aboveground biomass produces several important resources for other living things, including habitat and food. Conversely, dry and cold environments have lower photosynthetic rates and therefore less biomass. The animal communities living there will also be affected by the decrease in available food.
44.3 | Terrestrial Biomes
The Earth’s biomes are categorized into two major groups: terrestrial and aquatic. Terrestrial biomes are based on land, while aquatic biomes include both ocean and freshwater biomes. The eight major terrestrial biomes on Earth are each distinguished by characteristic temperatures and amount of precipitation. Comparing the annual totals of precipitation and fluctuations in precipitation from one biome to another provides clues as to the importance of abiotic factors in the distribution of biomes. Temperature variation on a daily and seasonal basis is also important for predicting the geographic distribution of the biome and the vegetation type in the biome. The distribution of these biomes shows that the same biome can occur in geographically distinct areas with similar climates (Figure 44.12).
Tropical Wet Forests
Tropical wet forests are also referred to as tropical rainforests. This biome is found in equatorial regions (Figure 44.12). The vegetation is characterized by plants with broad leaves that fall off throughout the year. Unlike the trees of deciduous forests, the trees in this biome do not have a seasonal loss of leaves associated with variations in temperature and sunlight; these forests are “evergreen” year-round.
The temperature and sunlight profiles of tropical wet forests are very stable in comparison to that of other terrestrial biomes, with the temperatures ranging from 20 °C to 34 °C (68 °F to 93 °F). When one compares the annual temperature variation of tropical wet forests with that of other forest biomes, the lack of seasonal temperature variation in the tropical wet forest becomes apparent. This lack of seasonality leads to year-round plant growth, rather than the seasonal (spring, summer, and fall) growth seen in other biomes. In contrast to other ecosystems, tropical ecosystems do not have long days and short days during the yearly cycle. Instead, a constant daily amount of sunlight (11–12 hrs per day) provides more solar radiation, thereby, a longer period of time for plant growth.
The annual rainfall in tropical wet forests ranges from 125 to 660 cm (50–200 in) with some monthly variation. While sunlight and temperature remain fairly consistent, annual rainfall is highly variable. Tropical wet forests have wet months in which there can be more than 30 cm (11–12 in) of precipitation, as well as dry months in which there are fewer than 10 cm (3.5 in) of rainfall. However, the driest month of a tropical wet forest still exceeds the annual rainfall of some other biomes, such as deserts.
Tropical wet forests have high net primary productivity because the annual temperatures and precipitation values in these areas are ideal for plant growth. Therefore, the extensive biomass present in the tropical wet forest leads to plant communities with very high species diversities (Figure 44.13). Tropical wet forests have more species of trees than any other biome; on average between 100 and 300 species of trees are present in a single hectare (2.5 acres) of South America. One way to visualize this is to compare the distinctive horizontal layers within the tropical wet forest biome. On the forest floor is a sparse layer of plants and decaying plant matter. Above that is an understory of short shrubby foliage. A layer of trees rises above this understory and is topped by a closed upper canopy—the uppermost overhead layer of branches and leaves. Some additional trees emerge through this closed upper canopy. These layers provide diverse and complex habitats for the variety of plants, fungi, animals, and other organisms within the tropical wet forests. For instance, epiphytes are plants that grow on other plants, which typically are not harmed. Epiphytes are found throughout tropical wet forest biomes. Many species of animals use the variety of plants and the complex structure of the tropical wet forests for food and shelter. Some organisms live several meters above ground and have adapted to this arboreal lifestyle.
Figure 44.13 Tropical wet forests, such as these forests of Madre de Dios, Peru, near the Amazon River, have high species diversity. (credit: Roosevelt Garcia)
Savannas
Savannas are grasslands with scattered trees, and they are located in Africa, South America, and northern Australia (Figure 44.12). Savannas are hot, tropical areas with temperatures averaging from 24 °C to 29 °C (75 °F to 84 °F) and an annual rainfall of 10–40 cm (3.9–15.7 in). Savannas have an extensive dry season; for this reason, forest trees do not grow as well as they do in the tropical wet forest (or other forest biomes). As a result, within the grasses and forbs (herbaceous flowering plants) that dominate the savanna, there are relatively few trees (Figure 44.14). Since fire is an important source of disturbance in this biome, plants have evolved well-developed root systems that allow them to quickly re-sprout after a fire.
Figure 44.14 Savannas, like this one in Taita Hills Wildlife Sanctuary in Kenya, are dominated by grasses. (credit: Christopher T. Cooper)
Subtropical Deserts
Subtropical deserts exist between 15 ° and 30 ° north and south latitude and are centered on the Tropics of Cancer and Capricorn (Figure 44.12). This biome is very dry; in some years, evaporation exceeds precipitation. Subtropical hot deserts can have daytime soil surface temperatures above 60 °C (140 °F) and nighttime temperatures approaching 0 °C (32 °F). In cold deserts, temperatures can be as high as 25 °C and can drop below -30 °C (-22 °F). Subtropical deserts are characterized by low annual precipitation of fewer than 30 cm (12 in) with little monthly variation and lack of predictability in rainfall. In some cases, the annual rainfall can be as low as 2 cm (0.8 in) in subtropical deserts located in central Australia (“the Outback”) and northern Africa.
The vegetation and low animal diversity of this biome is closely related to this low and unpredictable precipitation. Very dry deserts lack perennial vegetation that lives from one year to the next; instead, many plants are annuals that grow quickly and reproduce when rainfall does occur, then they die. Many other plants in these areas are characterized by having a number of adaptations that conserve water, such as deep roots, reduced foliage, and water-storing stems (Figure 44.15). Seed plants in the desert produce seeds that can be in dormancy for extended periods between rains. Adaptations in desert animals include nocturnal behavior and burrowing.
Figure 44.15 To reduce water loss, many desert plants have tiny leaves or no leaves at all. The leaves of ocotillo (Fouquieria splendens), shown here in the Sonora Desert near Gila Bend, Arizona, appear only after rainfall, and then are shed.
Chaparral
The chaparral is also called the scrub forest and is found in California, along the Mediterranean Sea, and along the southern coast of Australia (Figure 44.12). The annual rainfall in this biome ranges from 65 cm to 75 cm (25.6–29.5 in), and the majority of the rain falls in the winter. Summers are very dry and many chaparral plants are dormant during the summertime. The chaparral vegetation, shown in Figure 44.16, is dominated by shrubs and is adapted to periodic fires, with some plants producing seeds that only germinate after a hot fire. The ashes left behind after a fire are rich in nutrients like nitrogen that fertilize the soil and promote plant regrowth.
Figure 44.16 The chaparral is dominated by shrubs. (credit: Miguel Vieira)
Temperate Grasslands
Temperate grasslands are found throughout central North America, where they are also known as prairies; they are also in Eurasia, where they are known as steppes (Figure 44.12). Temperate grasslands have pronounced annual fluctuations in temperature with hot summers and cold winters. The annual temperature variation produces specific growing seasons for plants. Plant growth is possible when temperatures are warm enough to sustain plant growth and when ample water is available, which occurs in the spring, summer, and fall. During much of the winter, temperatures are low, and water, which is stored in the form of ice, is not available for plant growth.
Annual precipitation ranges from 25 cm to 75 cm (9.8–29.5 in). Because of relatively lower annual precipitation in temperate grasslands, there are few trees except for those found growing along rivers or streams. The dominant vegetation tends to consist of grasses and some prairies sustain populations of grazing animals Figure 44.17. The vegetation is very dense and the soils are fertile because the subsurface of the soil is packed with the roots and rhizomes (underground stems) of these grasses. The roots and rhizomes act to anchor plants into the ground and replenish the organic material (humus) in the soil when they die and decay.
Figure 44.17 The American bison (Bison bison), more commonly called the buffalo, is a grazing mammal that once populated American prairies in huge numbers. (credit: Jack Dykinga, USDA Agricultural Research Service)
Fires, mainly caused by lightning, are a natural disturbance in temperate grasslands. When fire is suppressed in temperate grasslands, the vegetation eventually converts to scrub and dense forests. Often, the restoration or management of temperate grasslands requires the use of controlled burns to suppress the growth of trees and maintain the grasses.
Temperate Forests
Temperate forests are the most common biome in eastern North America, Western Europe, Eastern Asia, Chile, and New Zealand (Figure 44.12). This biome is found throughout mid-latitude regions. Temperatures range between -30 °C and 30 °C (-22 °F to 86 °F) and drop to below freezing on an annual basis. These temperatures mean that temperate forests have defined growing seasons during the spring, summer, and early fall. Precipitation is relatively constant throughout the year and ranges between 75 cm and 150 cm (29.5–59 in).
Because of the moderate annual rainfall and temperatures, deciduous trees are the dominant plant in this biome (Figure 44.18). Deciduous trees lose their leaves each fall and remain leafless in the winter. Thus, no photosynthesis occurs in the deciduous trees during the dormant winter period. Each spring, new leaves appear as the temperature increases. Because of the dormant period, the net primary productivity of temperate forests is less than that of tropical wet forests. In addition, temperate forests show less diversity of tree species than tropical wet forest biomes.
Figure 44.18 Deciduous trees are the dominant plant in the temperate forest. (credit: Oliver Herold)
The trees of the temperate forests leaf out and shade much of the ground; however, this biome is more open than tropical wet forests because trees in the temperate forests do not grow as tall as the trees in tropical wet forests. The soils of the temperate forests are rich in inorganic and organic nutrients. This is due to the thick layer of leaf litter on forest floors. As this leaf litter decays, nutrients are returned to the soil. The leaf litter also protects soil from erosion, insulates the ground, and provides habitats for invertebrates (such as the pill bug or roly-poly, Armadillidium vulgare) and their predators, such as the red-backed salamander (Plethodon cinereus).
Boreal Forests
The boreal forest, also known as taiga or coniferous forest, is found south of the Arctic Circle and across most of Canada, Alaska, Russia, and northern Europe (Figure 44.12). This biome has cold, dry winters and short, cool, wet summers. The annual precipitation is from 40 cm to 100 cm (15.7–39 in) and usually takes the form of snow. Little evaporation occurs because of the cold temperatures.
The long and cold winters in the boreal forest have led to the predominance of cold-tolerant cone-bearing plants. These are evergreen coniferous trees like pines, spruce, and fir, which retain their needle-shaped leaves year-round. Evergreen trees can photosynthesize earlier in the spring than deciduous trees because less energy from the sun is required to warm a needle-like leaf than a broad leaf. This benefits evergreen trees, which grow faster than deciduous trees in the boreal forest. In addition, soils in boreal forest regions tend to be acidic with little available nitrogen. Leaves are a nitrogen-rich structure and deciduous trees must produce a new set of these nitrogen-rich structures each year. Therefore, coniferous trees that retain nitrogen-rich needles may have a competitive advantage over the broad-leafed deciduous trees.
The net primary productivity of boreal forests is lower than that of temperate forests and tropical wet forests. The aboveground biomass of boreal forests is high because these slow-growing tree species are long lived and accumulate standing biomass over time. Plant species diversity is less than that seen in temperate forests and tropical wet forests. Boreal forests lack the pronounced elements of the layered forest structure seen in tropical wet forests. The structure of a boreal forest is often only a tree layer and a ground layer (Figure 44.19). When conifer needles are dropped, they decompose more slowly than broad leaves; therefore, fewer nutrients are returned to the soil to fuel plant growth.
Figure 44.19 The boreal forest (taiga) has low lying plants and conifer trees. (credit: L.B. Brubaker)
Arctic Tundra
The Arctic tundra lies north of the subarctic boreal forest and is located throughout the Arctic regions of the northern hemisphere (Figure 44.12). The average winter temperature is -34 °C (-34 °F) and the average summer temperature is from 3 °C to 12 °C (37 °F–52 °F). Plants in the arctic tundra have a very short growing season of approximately 10–12 weeks. However, during this time, there are almost 24 hours of daylight and plant growth is rapid. The annual precipitation of the Arctic tundra is very low with little annual variation in precipitation. And, as in the boreal forests, there is little evaporation due to the cold temperatures.
Plants in the Arctic tundra are generally low to the ground (Figure 44.20). There is little species diversity, low net primary productivity, and low aboveground biomass. The soils of the Arctic tundra may remain in a perennially frozen state referred to as permafrost. The permafrost makes it impossible for roots to penetrate deep into the soil and slows the decay of organic matter, which inhibits the release of nutrients from organic matter. During the growing season, the ground of the Arctic tundra can be completely covered with plants or lichens.
Figure 44.20 Low-growing plants such as shrub willow dominate the tundra landscape, shown here in the Arctic National Wildlife Refuge. (credit: USFWS Arctic National Wildlife Refuge)
Watch this Assignment Discovery: Biomes video (http://openstaxcollege.org/l/biomes) for an overview of biomes. To explore further, select one of the biomes on the extended playlist: desert, savanna, temperate forest, temperate grassland, tropic, tundra.
44.4 | Aquatic Biomes
Abiotic Factors Influencing Aquatic Biomes
Like terrestrial biomes, aquatic biomes are influenced by a series of abiotic factors. The aquatic medium—water— has different physical and chemical properties than air, however. Even if the water in a pond or other body of water is perfectly clear (there are no suspended particles), water, on its own, absorbs light. As one descends into a deep body of water, there will eventually be a depth which the sunlight cannot reach. While there are some abiotic and biotic factors in a terrestrial ecosystem that might obscure light (like fog, dust, or insect swarms), usually these are not permanent features of the environment. The importance of light in aquatic biomes is central to the communities of organisms found in both freshwater and marine ecosystems. In freshwater systems, stratification due to differences in density is perhaps the most critical abiotic factor and is related to the energy aspects of light. The thermal properties of water (rates of heating and cooling) are significant to the function of marine systems and have major impacts on global climate and weather patterns. Marine systems are also influenced by large-scale physical water movements, such as currents; these are less important in most freshwater lakes.
The ocean is categorized by several areas or zones (Figure 44.21). All of the ocean’s open water is referred to as the pelagic realm (or zone). The benthic realm (or zone) extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor. Within the pelagic realm is the photic zone, which is the portion of the ocean that light can penetrate (approximately 200 m or 650 ft). At depths greater than 200 m, light cannot penetrate; thus, this is referred to as the aphotic zone. The majority of the ocean is aphotic and lacks sufficient light for photosynthesis. The deepest part of the ocean, the Challenger Deep (in the Mariana Trench, located in the western Pacific Ocean), is about 11,000 m (about 6.8 mi) deep. To give some perspective on the depth of this trench, the ocean is, on average, 4267 m or 14,000 ft deep. These realms and zones are relevant to freshwater lakes as well.
Marine Biomes
The ocean is the largest marine biome. It is a continuous body of salt water that is relatively uniform in chemical composition; it is a weak solution of mineral salts and decayed biological matter. Within the ocean, coral reefs are a second kind of marine biome. Estuaries, coastal areas where salt water and fresh water mix, form a third unique marine biome.
Ocean
The physical diversity of the ocean is a significant influence on plants, animals, and other organisms. The ocean is categorized into different zones based on how far light reaches into the water. Each zone has a distinct group of species adapted to the biotic and abiotic conditions particular to that zone.
The intertidal zone, which is the zone between high and low tide, is the oceanic region that is closest to land (Figure 44.21). Generally, most people think of this portion of the ocean as a sandy beach. In some cases, the intertidal zone is indeed a sandy beach, but it can also be rocky or muddy. The intertidal zone is an extremely variable environment because of tides. Organisms are exposed to air and sunlight at low tide and are underwater most of the time, especially during high tide. Therefore, living things that thrive in the intertidal zone are adapted to being dry for long periods of time. The shore of the intertidal zone is also repeatedly struck by waves, and the organisms found there are adapted to withstand damage from the pounding action of the waves (Figure 44.22). The exoskeletons of shoreline crustaceans (such as the shore crab, Carcinus maenas) are tough and protect them from desiccation (drying out) and wave damage. Another consequence of the pounding waves is that few algae and plants establish themselves in the constantly moving rocks, sand, or mud.
Figure 44.22 Sea urchins, mussel shells, and starfish are often found in the intertidal zone, shown here in Kachemak Bay, Alaska. (credit: NOAA)
The neritic zone (Figure 44.21) extends from the intertidal zone to depths of about 200 m (or 650 ft) at the edge of the continental shelf. Since light can penetrate this depth, photosynthesis can occur in the neritic zone. The water here contains silt and is well-oxygenated, low in pressure, and stable in temperature. Phytoplankton and floating Sargassum (a type of free-floating marine seaweed) provide a habitat for some sea life found in the neritic zone. Zooplankton, protists, small fishes, and shrimp are found in the neritic zone and are the base of the food chain for most of the world’s fisheries.
Beyond the neritic zone is the open ocean area known as the oceanic zone (Figure 44.21). Within the oceanic zone there is thermal stratification where warm and cold waters mix because of ocean currents. Abundant plankton serve as the base of the food chain for larger animals such as whales and dolphins. Nutrients are scarce and this is a relatively less productive part of the marine biome. When photosynthetic organisms and the protists and animals that feed on them die, their bodies fall to the bottom of the ocean where they remain; unlike freshwater lakes, the open ocean lacks a process for bringing the organic nutrients back up to the surface. The majority of organisms in the aphotic zone include sea cucumbers (phylum Echinodermata) and other organisms that survive on the nutrients contained in the dead bodies of organisms in the photic zone.
Beneath the pelagic zone is the benthic realm, the deepwater region beyond the continental shelf (Figure 44.21). The bottom of the benthic realm is comprised of sand, silt, and dead organisms. Temperature decreases, remaining above freezing, as water depth increases. This is a nutrient-rich portion of the ocean because of the dead organisms that fall from the upper layers of the ocean. Because of this high level of nutrients, a diversity of fungi, sponges, sea anemones, marine worms, sea stars, fishes, and bacteria exist.
The deepest part of the ocean is the abyssal zone, which is at depths of 4000 m or greater. The abyssal zone (Figure 44.21) is very cold and has very high pressure, high oxygen content, and low nutrient content. There are a variety of invertebrates and fishes found in this zone, but the abyssal zone does not have plants because of the lack of light. Hydrothermal vents are found primarily in the abyssal zone; chemosynthetic bacteria utilize the hydrogen sulfide and other minerals emitted from the vents. These chemosynthetic bacteria use the hydrogen sulfide as an energy source and serve as the base of the food chain found in the abyssal zone.
Coral Reefs
Coral reefs are ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean. They are found within 30˚ north and south of the equator. The Great Barrier Reef is a well-known reef system located several miles off the northeastern coast of Australia. Other coral reef systems are fringing islands, which are directly adjacent to land, or atolls, which are circular reef systems surrounding a former landmass that is now underwater. The coral organisms (members of phylum Cnidaria) are colonies of saltwater polyps that secrete a calcium carbonate skeleton. These calcium-rich skeletons slowly accumulate, forming the underwater reef (Figure 44.23). Corals found in shallower waters (at a depth of approximately 60 m or about 200 ft) have a mutualistic relationship with photosynthetic unicellular algae. The relationship provides corals with the majority of the nutrition and the energy they require. The waters in which these corals live are nutritionally poor and, without this mutualism, it would not be possible for large corals to grow. Some corals living in deeper and colder water do not have a mutualistic relationship with algae; these corals attain energy and nutrients using stinging cells on their tentacles to capture prey.
Watch this National Oceanic and Atmospheric Administration (NOAA) video (http://openstaxcollege.org/l/marine_biology) to see marine ecologist Dr. Peter Etnoyer discusses his research on coral organisms.
It is estimated that more than 4,000 fish species inhabit coral reefs. These fishes can feed on coral, the cryptofauna (invertebrates found within the calcium carbonate substrate of the coral reefs), or the seaweed and algae that are associated with the coral. In addition, some fish species inhabit the boundaries of a coral reef; these species include predators, herbivores, or planktivores. Predators are animal species that hunt and are carnivores or “flesh eaters.”
Figure 44.23 Coral reefs are formed by the calcium carbonate skeletons of coral organisms, which are marine invertebrates in the phylum Cnidaria. (credit: Terry Hughes)
Estuaries: Where the Ocean Meets Fresh Water
Estuaries are biomes that occur where a source of fresh water, such as a river, meets the ocean. Therefore, both fresh water and salt water are found in the same vicinity; mixing results in a diluted (brackish) saltwater. Estuaries form protected areas where many of the young offspring of crustaceans, mollusks, and fish begin their lives. Salinity is a very important factor that influences the organisms and the adaptations of the organisms found in estuaries. The salinity of estuaries varies and is based on the rate of flow of its freshwater sources. Once or twice a day, high tides bring salt water into the estuary. Low tides occurring at the same frequency reverse the current of salt water.
The short-term and rapid variation in salinity due to the mixing of fresh water and salt water is a difficult physiological challenge for the plants and animals that inhabit estuaries. Many estuarine plant species are halophytes: plants that can tolerate salty conditions. Halophytic plants are adapted to deal with the salinity resulting from saltwater on their roots or from sea spray. In some halophytes, filters in the roots remove the salt from the water that the plant absorbs. Other plants are able to pump oxygen into their roots. Animals, such as mussels and clams (phylum Mollusca), have developed behavioral adaptations that expend a lot of energy to function in this rapidly changing environment. When these animals are exposed to low salinity, they stop feeding, close their shells, and switch from aerobic respiration (in which they use gills) to anaerobic respiration (a process that does not require oxygen). When high tide returns to the estuary, the salinity and oxygen content of the water increases, and these animals open their shells, begin feeding, and return to aerobic respiration.
Freshwater Biomes
Freshwater biomes include lakes and ponds (standing water) as well as rivers and streams (flowing water). They also include wetlands, which will be discussed later. Humans rely on freshwater biomes to provide aquatic resources for drinking water, crop irrigation, sanitation, and industry. These various roles and human benefits are referred to as ecosystem services. Lakes and ponds are found in terrestrial landscapes and are, therefore, connected with abiotic and biotic factors influencing these terrestrial biomes.
Lakes and Ponds
Lakes and ponds can range in area from a few square meters to thousands of square kilometers. Temperature is an important abiotic factor affecting living things found in lakes and ponds. In the summer, thermal stratification of lakes and ponds occurs when the upper layer of water is warmed by the sun and does not mix with deeper, cooler water. Light can penetrate within the photic zone of the lake or pond. Phytoplankton (algae and cyanobacteria) are found here and carry out photosynthesis, providing the base of the food web of lakes and ponds. Zooplankton, such as rotifers and small crustaceans, consume these phytoplankton. At the bottom of lakes and ponds, bacteria in the aphotic zone break down dead organisms that sink to the bottom.
Nitrogen and phosphorus are important limiting nutrients in lakes and ponds. Because of this, they are determining factors in the amount of phytoplankton growth in lakes and ponds. When there is a large input of nitrogen and phosphorus (from sewage and runoff from fertilized lawns and farms, for example), the growth of algae skyrockets, resulting in a large accumulation of algae called an algal bloom. Algal blooms (Figure 44.24) can become so extensive that they reduce light penetration in water. As a result, the lake or pond becomes aphotic and photosynthetic plants cannot survive. When the algae die and decompose, severe oxygen depletion of the water occurs. Fishes and other organisms that require oxygen are then more likely to die, and resulting dead zones are found across the globe. Lake Erie and the Gulf of Mexico represent freshwater and marine habitats where phosphorus control and storm water runoff pose significant environmental challenges.
Figure 44.24 The uncontrolled growth of algae in this lake has resulted in an algal bloom. (credit: Jeremy Nettleton)
Rivers and Streams
Rivers and streams are continuously moving bodies of water that carry large amounts of water from the source, or headwater, to a lake or ocean. The largest rivers include the Nile River in Africa, the Amazon River in South America, and the Mississippi River in North America.
Abiotic features of rivers and streams vary along the length of the river or stream. Streams begin at a point of origin referred to as source water. The source water is usually cold, low in nutrients, and clear. The channel (the width of the river or stream) is narrower than at any other place along the length of the river or stream. Because of this, the current is often faster here than at any other point of the river or stream.
The fast-moving water results in minimal silt accumulation at the bottom of the river or stream; therefore, the water is clear. Photosynthesis here is mostly attributed to algae that are growing on rocks; the swift current inhibits the growth of phytoplankton. An additional input of energy can come from leaves or other organic material that falls into the river or stream from trees and other plants that border the water. When the leaves decompose, the organic material and nutrients in the leaves are returned to the water. Plants and animals have adapted to this fast-moving water. For instance, leeches (phylum Annelida) have elongated bodies and suckers on both ends. These suckers attach to the substrate, keeping the leech anchored in place. Freshwater trout species (phylum Chordata) are an important predator in these fast-moving rivers and streams.
As the river or stream flows away from the source, the width of the channel gradually widens and the current slows. This slow-moving water, caused by the gradient decrease and the volume increase as tributaries unite, has more sedimentation. Phytoplankton can also be suspended in slow-moving water. Therefore, the water will not be as clear as it is near the source. The water is also warmer. Worms (phylum Annelida) and insects (phylum Arthropoda) can be found burrowing into the mud. The higher order predator vertebrates (phylum Chordata) include waterfowl, frogs, and fishes. These predators must find food in these slow moving, sometimes murky, waters and, unlike the trout in the waters at the source, these vertebrates may not be able to use vision as their primary sense to find food. Instead, they are more likely to use taste or chemical cues to find prey.
Wetlands
Wetlands are environments in which the soil is either permanently or periodically saturated with water. Wetlands are different from lakes because wetlands are shallow bodies of water whereas lakes vary in depth. Emergent vegetation consists of wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water’s surface. There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes (Figure 44.25). The three shared characteristics among these types—what makes them wetlands—are their hydrology, hydrophytic vegetation, and hydric soils.
Figure 44.25 Located in southern Florida, Everglades National Park is vast array of wetland environments, including sawgrass marshes, cypress swamps, and estuarine mangrove forests. Here, a great egret walks among cypress trees.(credit: NPS)
Freshwater marshes and swamps are characterized by slow and steady water flow. Bogs develop in depressions where water flow is low or nonexistent. Bogs usually occur in areas where there is a clay bottom with poor percolation. Percolation is the movement of water through the pores in the soil or rocks. The water found in a bog is stagnant and oxygen depleted because the oxygen that is used during the decomposition of organic matter is not replaced. As the oxygen in the water is depleted, decomposition slows. This leads to organic acids and other acids building up and lowering the pH of the water. At a lower pH, nitrogen becomes unavailable to plants. This creates a challenge for plants because nitrogen is an important limiting resource. Some types of bog plants (such as sundews, pitcher plants, and Venus flytraps) capture insects and extract the nitrogen from their bodies. Bogs have low net primary productivity because the water found in bogs has low levels of nitrogen and oxygen.
44.5 | Climate and the Effects of Global Climate Change
All biomes are universally affected by global conditions, such as climate, that ultimately shape each biome’s environment. Scientists who study climate have noted a series of marked changes that have gradually become increasingly evident during the last sixty years. Global climate change is the term used to describe altered global weather patterns, including a worldwide increase in temperature, due largely to rising levels of atmospheric carbon dioxide.
Climate and Weather
A common misconception about global climate change is that a specific weather event occurring in a particular region (for example, a very cool week in June in central Indiana) is evidence of global climate change. However, a cold week in June is a weather-related event and not a climate-related one. These misconceptions often arise because of confusion over the terms climate and weather.
Climate refers to the long-term, predictable atmospheric conditions of a specific area. The climate of a biome is characterized by having consistent temperature and annual rainfall ranges. Climate does not address the amount of rain that fell on one particular day in a biome or the colder-than-average temperatures that occurred on one day. In contrast, weather refers to the conditions of the atmosphere during a short period of time. Weather forecasts are usually made for 48-hour cycles. Long-range weather forecasts are available but can be unreliable.
To better understand the difference between climate and weather, imagine that you are planning an outdoor event in northern Wisconsin. You would be thinking about climate when you plan the event in the summer rather than the winter because you have long-term knowledge that any given Saturday in the months of May to August would be a better choice for an outdoor event in Wisconsin than any given Saturday in January. However, you cannot determine the specific day that the event should be held on because it is difficult to accurately predict the weather on a specific day. Climate can be considered “average” weather.
Global Climate Change
Climate change can be understood by approaching three areas of study:
- current and past global climate change
- causes of past and present-day global climate change
- ancient and current results of climate change
It is helpful to keep these three different aspects of climate change clearly separated when consuming media reports about global climate change. It is common for reports and discussions about global climate change to confuse the data showing that Earth’s climate is changing with the factors that drive this climate change.
Evidence for Global Climate Change
Since scientists cannot go back in time to directly measure climatic variables, such as average temperature and precipitation, they must instead indirectly measure temperature. To do this, scientists rely on historical evidence of Earth’s past climate.
Antarctic ice cores are a key example of such evidence. These ice cores are samples of polar ice obtained by means of drills that reach thousands of meters into ice sheets or high mountain glaciers. Viewing the ice cores is like traveling backwards through time; the deeper the sample, the earlier the time period. Trapped within the ice are bubbles of air and other biological evidence that can reveal temperature and carbon dioxide data. Antarctic ice cores have been collected and analyzed to indirectly estimate the temperature of the Earth over the past 400,000 years (Figure 44.26a). The 0 °C on this graph refers to the long-term average. Temperatures that are greater than 0 °C exceed Earth’s long-term average temperature. Conversely, temperatures that are less than 0 °C are less than Earth’s average temperature. This figure shows that there have been periodic cycles of increasing and decreasing temperature.
Before the late 1800s, the Earth has been as much as 9 °C cooler and about 3 °C warmer. Note that the graph in Figure 44.26b shows that the atmospheric concentration of carbon dioxide has also risen and fallen in periodic cycles; note the relationship between carbon dioxide concentration and temperature. Figure 44.26b shows that carbon dioxide levels in the atmosphere have historically cycled between 180 and 300 parts per million (ppm) by volume.
Figure 44.26 Ice at the Russian Vostok station in East Antarctica was laid down over the course 420,000 years and reached a depth of over 3,000 m. By measuring the amount of CO2 trapped in the ice, scientists have determined past atmospheric CO2 concentrations. Temperatures relative to modern day were determined from the amount of deuterium (an isotope of hydrogen) present.
Figure 44.26a does not show the last 2,000 years with enough detail to compare the changes of Earth’s temperature during the last 400,000 years with the temperature change that has occurred in the more recent past. Two significant temperature anomalies, or irregularities, have occurred in the last 2000 years. These are the Medieval Climate Anomaly (or the Medieval Warm Period) and the Little Ice Age. A third temperature anomaly aligns with the Industrial Era. The Medieval Climate Anomaly occurred between 900 and 1300 AD. During this time period, many climate scientists think that slightly warmer weather conditions prevailed in many parts of the world; the higher-than-average temperature changes varied between 0.10 °C and 0.20 °C above the norm. Although 0.10 °C does not seem large enough to produce any noticeable change, it did free seas of ice. Because of this warming, the Vikings were able to colonize Greenland.
The Little Ice Age was a cold period that occurred between 1550 AD and 1850 AD. During this time, a slight cooling of a little less than 1 °C was observed in North America, Europe, and possibly other areas of the Earth. This 1 °C change in global temperature is a seemingly small deviation in temperature (as was observed during the Medieval Climate Anomaly); however, it also resulted in noticeable changes. Historical accounts reveal a time of exceptionally harsh winters with much snow and frost.
The Industrial Revolution, which began around 1750, was characterized by changes in much of human society. Advances in agriculture increased the food supply, which improved the standard of living for people in Europe and the United States. New technologies were invented and provided jobs and cheaper goods. These new technologies were powered using fossil fuels, especially coal. The Industrial Revolution starting in the early nineteenth century ushered in the beginning of the Industrial Era. When a fossil fuel is burned, carbon dioxide is released. With the beginning of the Industrial Era, atmospheric carbon dioxide began to rise (Figure 44.27).
Figure 44.27 The atmospheric concentration of CO2 has risen steadily since the beginning of industrialization.
Current and Past Drivers of Global Climate Change
Since it is not possible to go back in time to directly observe and measure climate, scientists use indirect evidence to determine the drivers, or factors, that may be responsible for climate change. The indirect evidence includes data collected using ice cores, boreholes (a narrow shaft bored into the ground), tree rings, glacier lengths, pollen remains, and ocean sediments. The data shows a correlation between the timing of temperature changes and drivers of climate change: before the Industrial Era (pre-1780), there were three drivers of climate change that were not related to human activity or atmospheric gases. The first of these is the Milankovitch cycles. The Milankovitch cycles describe the effects of slight changes in the Earth’s orbit on Earth’s climate. The length of the Milankovitch cycles ranges between 19,000 and 100,000 years. In other words, one could expect to see some predictable changes in the Earth’s climate associated with changes in the Earth’s orbit at a minimum of every 19,000 years.
The variation in the sun’s intensity is the second natural factor responsible for climate change. Solar intensity is the amount of solar power or energy the sun emits in a given amount of time. There is a direct relationship between solar intensity and temperature. As solar intensity increases (or decreases), the Earth’s temperature correspondingly increases (or decreases). Changes in solar intensity have been proposed as one of several possible explanations for the Little Ice Age.
Finally, volcanic eruptions are a third natural driver of climate change. Volcanic eruptions can last a few days, but the solids and gases released during an eruption can influence the climate over a period of a few years, causing short-term climate changes. The gases and solids released by volcanic eruptions can include carbon dioxide, water vapor, sulfur dioxide, hydrogen sulfide, hydrogen, and carbon monoxide. Generally, volcanic eruptions cool the climate. This occurred in 1783 when volcanos in Iceland erupted and caused the release of large volumes of sulfuric oxide. This led to haze-effect cooling, a global phenomenon that occurs when dust, ash, or other suspended particles block out sunlight and trigger lower global temperatures as a result; haze-effect cooling usually extends for one or more years. In Europe and North America, haze-effect cooling produced some of the lowest average winter temperatures on record in 1783 and 1784.
Greenhouse gases are probably the most significant drivers of the climate. When heat energy from the sun strikes the Earth, gases known as greenhouse gases trap the heat in the atmosphere, as do the glass panes of a greenhouse keep heat from escaping. The greenhouse gases that affect Earth include carbon dioxide, methane, water vapor, nitrous oxide, and ozone. Approximately half of the radiation from the sun passes through these gases in the atmosphere and strikes the Earth. This radiation is converted into thermal radiation on the Earth’s surface, and then a portion of that energy is re-radiated back into the atmosphere. Greenhouse gases, however, reflect much of the thermal energy back to the Earth’s surface. The more greenhouse gases there are in the atmosphere, the more thermal energy is reflected back to the Earth’s surface. Greenhouse gases absorb and emit radiation and are an important factor in the greenhouse effect: the warming of Earth due to carbon dioxide and other greenhouse gases in the atmosphere.
Evidence supports the relationship between atmospheric concentrations of carbon dioxide and temperature: as carbon dioxide rises, global temperature rises. Since 1950, the concentration of atmospheric carbon dioxide has increased from about 280 ppm to 382 ppm in 2006. In 2011, the atmospheric carbon dioxide concentration was 392 ppm. However, the planet would not be inhabitable by current life forms if water vapor did not produce its drastic greenhouse warming effect.
Scientists look at patterns in data and try to explain differences or deviations from these patterns. The atmospheric carbon dioxide data reveal a historical pattern of carbon dioxide increasing and decreasing, cycling between a low of 180 ppm and a high of 300 ppm. Scientists have concluded that it took around 50,000 years for the atmospheric carbon dioxide level to
increase from its low minimum concentration to its higher maximum concentration. However, starting recently, atmospheric carbon dioxide concentrations have increased beyond the historical maximum of 300 ppm. The current increases in atmospheric carbon dioxide have happened very quickly—in a matter of hundreds of years rather than thousands of years. What is the reason for this difference in the rate of change and the amount of increase in carbon dioxide? A key factor that must be recognized when comparing the historical data and the current data is the presence of modern human society; no other driver of climate change has yielded changes in atmospheric carbon dioxide levels at this rate or to this magnitude.
Human activity releases carbon dioxide and methane, two of the most important greenhouse gases, into the atmosphere in several ways. The primary mechanism that releases carbon dioxide is the burning of fossil fuels, such as gasoline, coal, and natural gas (Figure 44.28). Deforestation, cement manufacture, animal agriculture, the clearing of land, and the burning of forests are other human activities that release carbon dioxide. Methane (CH4) is produced when bacteria break down organic matter under anaerobic conditions. Anaerobic conditions can happen when organic matter is trapped underwater (such as in rice paddies) or in the intestines of herbivores. Methane can also be released from natural gas fields and the decomposition that occurs in landfills. Another source of methane is the melting of clathrates. Clathrates are frozen chunks of ice and methane found at the bottom of the ocean. When water warms, these chunks of ice melt and methane is released. As the ocean’s water temperature increases, the rate at which clathrates melt is increasing, releasing even more methane. This leads to increased levels of methane in the atmosphere, which further accelerates the rate of global warming. This is an example of the positive feedback loop that is leading to the rapid rate of increase of global temperatures.
Figure 44.28 The burning of fossil fuels in industry and by vehicles releases carbon dioxide and other greenhouse gases into the atmosphere. (credit: “Pöllö”/Wikimedia Commons)
Documented Results of Climate Change: Past and Present
Scientists have geological evidence of the consequences of long-ago climate change. Modern-day phenomena such as retreating glaciers and melting polar ice cause a continual rise in sea level. Meanwhile, changes in climate can negatively affect organisms.
Geological Climate Change
Global warming has been associated with at least one planet-wide extinction event during the geological past. The Permian extinction event occurred about 251 million years ago toward the end of the roughly 50-million-year-long geological time span known as the Permian period. This geologic time period was one of the three warmest periods in Earth’s geologic history. Scientists estimate that approximately 70 percent of the terrestrial plant and animal species and 84 percent of marine species became extinct, vanishing forever near the end of the Permian period. Organisms that had adapted to wet and warm climatic conditions, such as annual rainfall of 300–400 cm (118–157 in) and 20 °C–30 °C (68 °F–86 °F) in the tropical wet forest, may not have been able to survive the Permian climate change.
Watch this NASA video (http://openstaxcollege.org/l/climate_plants) to discover the mixed effects of global warming on plant growth. While scientists found that warmer temperatures in the 1980s and 1990s caused an increase in plant productivity, this advantage has since been counteracted by more frequent droughts.
Present Climate Change
A number of global events have occurred that may be attributed to climate change during our lifetimes. Glacier National Park in Montana is undergoing the retreat of many of its glaciers, a phenomenon known as glacier recession. In 1850, the area contained approximately 150 glaciers. By 2010, however, the park contained only about 24 glaciers greater than 25 acres in size. One of these glaciers is the Grinnell Glacier (Figure 44.29) at Mount Gould. Between 1966 and 2005, the size of Grinnell Glacier shrank by 40 percent. Similarly, the mass of the ice sheets in Greenland and the Antarctic is decreasing:
Greenland lost 150–250 km3 of ice per year between 2002 and 2006. In addition, the size and thickness of the Arctic sea ice is decreasing.
Figure 44.29 The effect of global warming can be seen in the continuing retreat of Grinnel Glacier. The mean annual temperature in the park has increased 1.33 °C since 1900. The loss of a glacier results in the loss of summer meltwaters, sharply reducing seasonal water supplies and severely affecting local ecosystems. (credit: modification of work by USGS)
This loss of ice is leading to increases in the global sea level. On average, the sea is rising at a rate of 1.8 mm per year. However, between 1993 and 2010 the rate of sea level increase ranged between 2.9 and 3.4 mm per year. A variety of factors affect the volume of water in the ocean, including the temperature of the water (the density of water is related to its temperature) and the amount of water found in rivers, lakes, glaciers, polar ice caps, and sea ice. As glaciers and polar ice caps melt, there is a significant contribution of liquid water that was previously frozen.
In addition to some abiotic conditions changing in response to climate change, many organisms are also being affected by the changes in temperature. Temperature and precipitation play key roles in determining the geographic distribution and phenology of plants and animals. (Phenology is the study of the effects of climatic conditions on the timing of periodic lifecycle events, such as flowering in plants or migration in birds.) Researchers have shown that 385 plant species in Great Britain are flowering 4.5 days sooner than was recorded earlier during the previous 40 years. In addition, insect-pollinated species were more likely to flower earlier than wind-pollinated species. The impact of changes in flowering date would be mitigated if the insect pollinators emerged earlier. This mismatched timing of plants and pollinators could result in injurious ecosystem effects because, for continued survival, insect-pollinated plants must flower when their pollinators are present.
KEY TERMS
nonliving components of the environment
total mass of aboveground living plants per area
deepest part of the ocean at depths of 4000 m or greater
rapid increase of algae in an aquatic system
part of the ocean where no light penetrates
(also, benthic zone) part of the ocean that extends along the ocean bottom from the shoreline to the deepest
parts of the ocean floor
study of the geographic distribution of living things and the abiotic factors that affect their distribution
ecological community of plants, animals, and other organisms that is adapted to a characteristic set of
environmental conditions
living components of the environment
branches and foliage of trees that form a layer of overhead coverage in a forest
width of a river or stream from one bank to the other bank
frozen chunks of ice and methane found at the bottom of the ocean
long-term, predictable atmospheric conditions present in a specific area
individuals that are members of the same species
ocean ridges formed by marine invertebrates living in warm, shallow waters within the photic zone
invertebrates found within the calcium carbonate substrate of coral reefs
study of interaction between living things and their environment
human benefits and services provided by natural ecosystems
wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending
above the water’s surface
species found only in a specific geographic area that is usually restricted in size
biomes where a source of fresh water, such as a river, meets the ocean
seasonal process that recycles nutrients and oxygen from the bottom of a freshwater ecosystem
to the top
altered global weather patterns, including a worldwide increase in temperature, due largely to
rising levels of atmospheric carbon dioxide
warming of Earth due to carbon dioxide and other greenhouse gases in the atmosphere
atmospheric gases such as carbon dioxide and methane that absorb and emit radiation, thus trapping
heat in Earth’s atmosphere
effect of the gases and solids from a volcanic eruption on global climate
individuals that are members of different species
part of the ocean that is closest to land; parts extend above the water at low tide
Chapter 44 | Ecology and the Biosphere 1313
Milankovitch cycles
neritic zone
net primary productivity
ocean upwelling
oceanic zone
pelagic realm
permafrost
photic zone
planktivore
predator
Sargassum
solar intensity
source water
thermocline
weather
cyclic changes in the Earth’s orbit that may affect climate
part of the ocean that extends from low tide to the edge of the continental shelf
measurement of the energy accumulation within an ecosystem, calculated as the total amount
of carbon fixed per year minus the amount that is oxidized during cellular respiration
rising of deep ocean waters that occurs when prevailing winds blow along surface waters near a
coastline
part of the ocean that begins offshore where the water measures 200 m deep or deeper
(also, pelagic zone) open ocean waters that are not close to the bottom or near the shore
perennially frozen portion of the Arctic tundra soil
portion of the ocean that light can penetrate
animal species that eats plankton
animal species that hunt and are carnivores or “flesh eaters”
type of free-floating marine seaweed
amount of solar power energy the sun emits in a given amount of time
point of origin of a river or stream
layer of water with a temperature that is significantly different from that of the surrounding layers
conditions of the atmosphere during a short period of time
CHAPTER SUMMARY
44.1 The Scope of Ecology
Ecology is the study of the interactions of living things with their environment. Ecologists ask questions across four levels
of biological organization—organismal, population, community, and ecosystem. At the population and community levels, ecologists
explore, respectively, how a population of organisms changes over time and the ways in which that population interacts
with other species in the community. Ecologists studying an ecosystem examine the living species (the biotic components)
of the ecosystem as well as the nonliving portions (the abiotic components), such as air, water, and soil, of the
environment.
44.2 Biogeography
Biogeography is the study of the geographic distribution of living things and the abiotic factors that affect their
distribution. Endemic species are species that are naturally found only in a specific geographic area. The distribution of
living things is influenced by several environmental factors that are, in part, controlled by the latitude or elevation at which
an organism is found. Ocean upwelling and spring and fall turnovers are important processes regulating the distribution of
nutrients and other abiotic factors important in aquatic ecosystems. Energy sources, temperature, water, inorganic
nutrients, and soil are factors limiting the distribution of living things in terrestrial systems. Net primary productivity is a
measure of the amount of biomass produced by a biome.
44.3 Terrestrial Biomes
The Earth has terrestrial biomes and aquatic biomes. Aquatic biomes include both freshwater and marine environments.
There are eight major terrestrial biomes: tropical wet forests, savannas, subtropical deserts, chaparral, temperate
grasslands, temperate forests, boreal forests, and Arctic tundra. The same biome can occur in different geographic
locations with similar climates. Temperature and precipitation, and variations in both, are key abiotic factors that shape the
composition of animal and plant communities in terrestrial biomes. Some biomes, such as temperate grasslands and
temperate forests, have distinct seasons, with cold weather and hot weather alternating throughout the year. In warm, moist
1314 Chapter 44 | Ecology and the Biosphere
This OpenStax book is available for free at http://cnx.org/content/col11448/1.10
biomes, such as the tropical wet forest, net primary productivity is high, as warm temperatures, abundant water, and a
year-round growing season fuel plant growth. Other biomes, such as deserts and tundra, have low primary productivity due
to extreme temperatures and a shortage of available water.
44.4 Aquatic Biomes
Aquatic ecosystems include both saltwater and freshwater biomes. The abiotic factors important for the structuring of
aquatic ecosystems can be different than those seen in terrestrial systems. Sunlight is a driving force behind the structure
of forests and also is an important factor in bodies of water, especially those that are very deep, because of the role of
photosynthesis in sustaining certain organisms. Density and temperature shape the structure of aquatic systems. Oceans
may be thought of as consisting of different zones based on water depth and distance from the shoreline and light
penetrance. Different kinds of organisms are adapted to the conditions found in each zone. Coral reefs are unique marine
ecosystems that are home to a wide variety of species. Estuaries are found where rivers meet the ocean; their shallow
waters provide nourishment and shelter for young crustaceans, mollusks, fishes, and many other species. Freshwater
biomes include lakes, ponds, rivers, streams, and wetlands. Bogs are an interesting type of wetland characterized by
standing water, lower pH, and a lack of nitrogen.
44.5 Climate and the Effects of Global Climate Change
The Earth has gone through periodic cycles of increases and decreases in temperature. During the past 2000 years, the
Medieval Climate Anomaly was a warmer period, while the Little Ice Age was unusually cool. Both of these irregularities
can be explained by natural causes of changes in climate, and, although the temperature changes were small, they had
significant effects. Natural drivers of climate change include Milankovitch cycles, changes in solar activity, and volcanic
eruptions. None of these factors, however, leads to rapid increases in global temperature or sustained increases in carbon
dioxide. The burning of fossil fuels is an important source of greenhouse gases, which plays a major role in the greenhouse
effect. Long ago, global warming resulted in the Permian extinction: a large-scale extinction event that is documented in
the fossil record. Currently, modern-day climate change is associated with the increased melting of glaciers and polar ice
sheets, resulting in a gradual increase in sea level. Plants and animals can also be affected by global climate change when
the timing of seasonal events, such as flowering or pollination, is affected by global warming.
ART CONNECTION QUESTIONS
1. Figure 44.10 How might turnover in tropical lakes
differ from turnover in lakes that exist in temperate
regions?
2. Figure 44.12 Which of the following statements about
biomes is false?
a. Chaparral is dominated by shrubs.
b. Savannas and temperate grasslands are
dominated by grasses.
c. Boreal forests are dominated by deciduous trees.
d. Lichens are common in the arctic tundra.
3. Figure 44.21 In which of the following regions would
you expect to find photosynthetic organisms?
a. the aphotic zone, the neritic zone, the oceanic
zone, and the benthic realm
b. the photic zone, the intertidal zone, the neritic
zone, and the oceanic zone
c. the photic zone, the abyssal zone, the neritic
zone, and the oceanic zone
d. the pelagic realm, the aphotic zone, the neritic
zone, and the oceanic zone
REVIEW QUESTIONS
4. Which of the following is a biotic factor?
a. wind
b. disease-causing microbe
c. temperature
d. soil particle size
5. The study of nutrient cycling though the environment is
an example of which of the following?
a. organismal ecology
b. population ecology
c. community ecology
d. ecosystem ecology
6. Understory plants in a temperate forest have adaptations
to capture limited ________.
a. water
b. nutrients
c. heat
d. sunlight
7. An ecologist hiking up a mountain may notice different
biomes along the way due to changes in all of the
following except:
a. elevation
b. rainfall
c. latitude
d. temperature
Chapter 44 | Ecology and the Biosphere 1315
8. Which of the following biomes is characterized by
abundant water resources?
a. deserts
b. boreal forests
c. savannas
d. tropical wet forests
9. Which of the following biomes is characterized by short
growing seasons?
a. deserts
b. tropical wet forests
c. Arctic tundras
d. savannas
10. Where would you expect to find the most
photosynthesis in an ocean biome?
a. aphotic zone
b. abyssal zone
c. benthic realm
d. intertidal zone
11. A key feature of estuaries is:
a. low light conditions and high productivity
b. salt water and fresh water
c. frequent algal blooms
d. little or no vegetation
12. Which of the following is an example of a weather
event?
a. The hurricane season lasts from June 1 through
November 30.
b. The amount of atmospheric CO2 has steadily
increased during the last century.
c. A windstorm blew down trees in the Boundary
Waters Canoe Area in Minnesota on July 4,
1999.
d. Deserts are generally dry ecosystems having
very little rainfall.
13. Which of the following natural forces is responsible
for the release of carbon dioxide and other atmospheric
gases?
a. the Milankovitch cycles
b. volcanoes
c. solar intensity
d. burning of fossil fuels
CRITICAL THINKING QUESTIONS
14. Ecologists often collaborate with other researchers
interested in ecological questions. Describe the levels of
ecology that would be easier for collaboration because of
the similarities of questions asked. What levels of ecology
might be more difficult for collaboration?
15. The population is an important unit in ecology as well
as other biological sciences. How is a population defined,
and what are the strengths and weaknesses of this
definition? Are there some species that at certain times or
places are not in populations?
16. Compare and contrast ocean upwelling and spring and
fall turnovers.
17. Many endemic species are found in areas that are
geographically isolated. Suggest a plausible scientific
explanation for why this is so.
18. The extremely low precipitation of subtropical desert
biomes might lead one to expect fire to be a major
disturbance factor; however, fire is more common in the
temperate grassland biome than in the subtropic desert
biome. Why is this?
19. In what ways are the subtropical desert and the arctic
tundra similar?
20. Scientists have discovered the bodies of humans and
other living things buried in bogs for hundreds of years,
but not yet decomposed. Suggest a possible biological
explanation for why such bodies are so well-preserved.
21. Describe the conditions and challenges facing
organisms living in the intertidal zone.
22. Compare and contrast how natural- and humaninduced
processes have influenced global climate change.
23. Predict possible consequences if carbon emissions
from fossil fuels continue to rise.
Adapted from:
OpenStax, Biology. OpenStax. May 20, 2013. <http://cnx.org/content/col11448/latest/>
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V2GYLPFoF04DYqwX | 9.2: Direct Materials Budget | 9.2: Direct Materials Budget
Learning Outcomes
- Create a direct materials budget
Hupana Running Company is off to a great budgeting start!! We have put together a sales budget, so we know how many pairs of our amazing running shoes we intend to sell, then we created a production budget, so now we know how many we need to produce each quarter to meet sales and finished inventory needs!
Ok, so next, we will need to figure out, based off the information in our production budget, what we need for direct materials! Remember, the number of pairs of shoes we sell each quarter, does not necessarily match the number of pairs we need to produce each quarter. Keeping that information in mind, let’s move on to our direct materials budget.
In order to complete this budget, let’s look at a few pieces of important information.
- How many units of raw materials are required for each pair of shoes?
- How many units do we need to meet our production budget?
- How many units of raw materials would we like to have in our ending inventory?
- What do we currently have in our raw materials inventory?
- How many units of raw materials do we need to purchase?
- How much does each unit of raw material cost?
Let’s assume we are showing 250 units of raw material in our ending inventory coming into the new year. Each pair of shoes we make requires 5 units of raw materials. Let’s also note that our buyer has secured a price for our raw material of $2 per unit for the entire year! Yeah to our buyer for doing great work on an annual contract! This will certainly help us in our budgeting process right?
This information will help our buyers to purchase raw materials, especially if it has a long lead time to receive, or if we like to receive it close to needing it (this might be called JIT or just-in-time inventory!).
| Hupana Running Company Direct Materials Budget | |||||
|---|---|---|---|---|---|
| Quarter | Q1 | Q2 | Q3 | Q4 | Total |
| Required production in pairs | 450 | 500 | 500 | 600 | 2050 |
| Units of raw material needed per pair | 5 | 5 | 5 | 5 | 5 |
| Units of raw material needed to meet production | 2250 | 2500 | 2500 | 3000 | 10250 |
| Plus desired ending raw material inventory | 500 | 500 | 500 | 500 | 500 |
| Total units of raw materials needed | 2750 | 3000 | 3000 | 3500 | 10750 |
| Less units in beginning raw material inventory | 250 | 500 | 500 | 500 | 250 |
| Units of raw materials to be purchases | 2500 | 2500 | 2500 | 3000 | 10500 |
| Cost of raw material per unit | $2 | $2 | $2 | $2 | $2 |
| Cost of raw material to be purchased | $5,000 | $5,000 | $5,000 | $6,000 | $21,000 |
What information is helpful? We now know how much money we need to have each quarter to cover the cost of our raw materials. Our buyer is happy and so is our production manager, knowing that we will have raw material in stock for production!
We can use this information to start working on the next part of our budget! What comes next? Well labor of course!
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YSzclo1vieF9qWky | 1.2: Subsets | 1.2: Subsets
After completing this section, you should be able to:
- Represent subsets and proper subsets symbolically.
- Compute the number of subsets of a set.
- Apply concepts of subsets and equivalent sets to finite and infinite sets.
The rules of Major League Soccer (MLS) allow each team to have up to 30 players on their team. However, only 18 of these players can be listed on the game day roster, and of the 18 listed, 11 players must be selected to start the game. How the coaches and general managers form the team and choose the starters for each game will determine the success of the team in any given year.
The entire group of 30 players is each team’s set. The group of game day players is a subset of the team set, and the group of 11 starters is a subset of both the team set and the set of players on the game day roster.
Set is a subset of set if every member of set is also a member of set . Symbolically, this relationship is written as .
Sets can be related to each other in several different ways: they may not share any members in common, they may share some members in common, or they may share all members in common. In this section, we will explore the way we can select a group of members from the whole set.
Checkpoint
Every set is also a subset of itself,
Recall the set of flatware in our kitchen drawer from Section 1.1,
. Suppose you are preparing to eat dinner, so you pull a fork and a knife from the drawer to set the table. The set is a subset of set , because every member or element of set is also a member of set . More specifically, set is a proper subset of set , because there are other members of set not in set . This is written as . The only subset of a set that is not a proper subset of the set would be the set itself.
Checkpoint
The empty set or null set, , is a proper subset of every set, except itself.
Graphically, sets are often represented as circles. In the following graphic, set is represented as a circle completely enclosed inside the circle representing set , showing that set is a proper subset of set . The element represents an element that is in both set and set .
Figure 1.5Checkpoint
While we can list all the subsets of a finite set, it is not possible to list all the possible subsets of an infinite set, as it would take an infinitely long time.
Example 1.11
Listing All the Proper Subsets of a Finite Set
Set is a set of reading materials available in a shop at the airport, . List all the subsets of set .
- Answer
-
Step 1: It is best to begin with the set itself, as every set is a subset of itself. In our example, the cardinality of set is . There is only one subset of set that has the same number of elements of set .
Step 2: Next, list all the proper subsets of the set containing elements. In this case, . There are three subsets that each contain two elements: , , and .
Step 3: Continue this process by listing all the proper subsets of the set containing elements. In this case, . There are three subsets that contain one element: , , and .
Step 4: Finally, list the subset containing 0 elements, or the empty set: .
Your Turn 1.11
Consider the set of possible outcomes when you flip a coin, /**/S = \{ {\text{heads, tails}}\} /**/ . List all the possible subsets of set /**/S./**/
Example 1.12
Determining Whether a Set Is a Proper Subset
Consider the set of common political parties in the United States, . Determine if the following sets are proper subsets of .
- Answer
-
- is a proper subset of , written symbolically as because every member of is a member of set , but also contains at least one element that is not in .
- is a single member proper subset of , written symbolically as because Green is a member of set , but also contains other members (such as Democratic) that are not in .
- is subset of because every member of is also a member of , but it is not a proper subset of because there are no members of that are not also in set . We can represent the relationship symbolically as or more precisely, set is equal to set ,
Your Turn 1.12
Consider the set of generation I legendary Pokémon, /**/L = \{ {\text{Articuno, Zapdos, Moltres, Mewtwo}}\} /**/ . Give an example of a proper subset containing:
Example 1.13
Expressing the Relationship between Sets Symbolically
Consider the subsets of a standard deck of cards: ; ; ; and .
Express the relationship between the following sets symbolically.
- Set and set .
- Set and set .
- Set and .
- Answer
-
- . is a proper subset of set .
- . is a proper subset of set .
-
R or R = R . is subset of itself, but not a proper subset of itself because is equal to itself.R ⊆ R or R = R
Your Turn 1.13
Exponential Notation
So far, we have figured out how many subsets exist in a finite set by listing them. Recall that in Example 1.11, when we listed all the subsets of the three-element set \(L=\{\) newspaper, magazine, book\} we saw that there are eight subsets. In Your Turn 1.11, we discovered that there are four subsets of the two-element subset, \(S=\{\) heads, tails \(\}\). A one-element set has two subsets, the empty set and itself. The only subset of the empty set is the empty set itself. But how can we easily figure out the number of subsets in a very large finite set? It turns out that the number of subsets can be found by raising 2 to the number of elements in the set, using exponential notation to represent repeated multiplication. For example, the number of subsets of the set \(L=\{\) newspaper, magazine, book \(\}\) is equal to \(2^3=2 \cdot 2 \cdot 2=8\). Exponential notation is used to represent repeated multiplication, \(b^n=b \cdot b \cdot b \cdot \ldots \cdot b\), where \(b\) appears as a factor \(n\) times.
FORMULA
The number of subsets of a finite set is equal to 2 raised to the power of , where is the number of elements in set : .
Checkpoint
Note that , so this formula works for the empty set, also.
Example 1.14
Computing the Number of Subsets of a Set
Find the number of subsets of each of the following sets.
-
The set of top five scorers of all time in the NBA:
\(S=\{\) LeBron James, Kareem Abdul-Jabbar, Karl Malone, Kobe Bryant, Michael Jordan -
The set of the top four bestselling albums of all time:
\(A=\{\) Thriller, Hotel California, The Beatles White Album, Led Zepplin IV \(\}\). - \(R=\{\) Snap, Crackle, Pop \(\}\).
- Answer
-
-
. So, the total number of subsets of
S is 2 5 = 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 = 32 S is 2 5 .= 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 = 32 -
. Therefore, the total number of subsets of
A is 2 4 = 16 A is 2 4 .= 16 -
. So, the total number of subsets of
R is 2 3 = 8 R is 2 3 .= 8
-
. So, the total number of subsets of
Your Turn 1.14
Equivalent Subsets
In the early 17th century, the famous astronomer Galileo Galilei found that the set of natural numbers and the subset of the natural numbers consisting of the set of square numbers,
Sequences and series are defined as infinite subsets of the set of natural numbers by forming a relationship between the sequence or series in terms of a natural number, . For example, the set of even numbers can be defined using set builder notation as . The formula in this case replaces every natural number with two times the number, resulting in the set of even numbers, . The set of even numbers is also equivalent to the set of natural numbers.
Who Knew?
Employment Opportunities
You can make a career out of working with sets. Applications of equivalent sets include relational database design and analysis.
Relational databases that store data are tables of related information. Each row of a table has the same number of columns as every other row in the table; in this way, relational databases are examples of set equivalences for finite sets. In a relational database, a primary key is set up to identify all related information. There is a one-to-one relationship between the primary key and any other information associated with it.
Database design and analysis is a high demand career with a median entry-level salary of about $85,000 per year, according to salary.com.
Example 1.15
Writing Equivalent Subsets of an Infinite Set
Using natural numbers, multiples of 3 are given by the sequence . Write this set using set builder notation by expressing each multiple of 3 using a formula in terms of a natural number, .
- Answer
-
or . In this example, is a multiple of 3 and is a natural number. The symbol is read as “is a member or element of.” Because there is a one-to-one correspondence between the set of multiples of 3 and the natural numbers, the set of multiples of 3 is an equivalent subset of the natural numbers.
Your Turn 1.15
Example 1.16
Creating Equivalent Subsets of a Finite Set That Are Not Equal
A fast-food restaurant offers a deal where you can select two options from the following set of four menu items for $6: a chicken sandwich, a fish sandwich, a cheeseburger, or 10 chicken nuggets. Javier and his friend Michael are each purchasing lunch using this deal. Create two equivalent, but not equal, subsets that Javier and Michael could choose to have for lunch.
- Answer
-
The possible two-element subsets are: {chicken sandwich, fish sandwich}, {chicken sandwich, cheeseburger}, {chicken sandwich, chicken nuggets}, {fish sandwich, cheeseburger}, {fish sandwich, chicken nuggets}, and {cheeseburger, chicken nuggets}. One possible solution is that Javier picked the set {chicken sandwich, chicken nuggets}, while Michael chose the {cheeseburger, chicken nuggets}. Because Javier and Michael both picked two items, but not exactly the same two items, these sets are equivalent, but not equal.
Your Turn 1.16
Example 1.17
Creating Equivalent Subsets of a Finite Set
A high school volleyball team at a small school consists of the following players: {Angie, Brenda, Colleen, Estella, Maya, Maria, Penny, Shantelle}. Create two possible equivalent starting line-ups of six players that the coach could select for the next game.
- Answer
-
There are actually 28 possible ways that the coach could choose his starting line-up. Two such equivalent subsets are {Angie, Brenda, Maya, Maria, Penny, Shantelle} and {Angie, Brenda, Colleen, Estella, Maria, Shantelle}. Each subset has six members, but they are not identical, so the two sets are equivalent but not equal.
Your Turn 1.17
Check Your Understanding
9. Explain what distinguishes a proper subset of a set from a subset of a set.
10. The ________ set is a proper subset of every set except itself.
11. Is the following statement true or false? \(A \subseteq A\).
12. If the cardinality of set \(A\) is \(n(A)=10\), then set \(A\) has a total of ________ subsets.
13. Set \(A\) is ________ to set \(B\) if \(n(A)=n(B)\).
14. If every member of set \(A\) is a member of set \(B\) and every member of set \(B\) is also a member set \(A\), then set \(A\) is ________ to set \(B\). | 2,611 | common-pile/libretexts_filtered | https://math.libretexts.org/Bookshelves/Applied_Mathematics/Contemporary_Mathematics_(OpenStax)/01%3A__Sets/1.02%3A_Subsets | libretexts | libretexts-0000.json.gz:43509 | https://math.libretexts.org/Bookshelves/Applied_Mathematics/Contemporary_Mathematics_(OpenStax)/01%3A__Sets/1.02%3A_Subsets |
udMVMb_1_R3ezbol | The Underground Railroad | He had the good fortune to escape from Edward H. Hubbert, a ship timber merchant of Norfolk, Va. Under Hubbert’s yoke he had served only five years, having been bought by him from a certain Aldridge Mandrey, who was described as a “very cruel man,” and would “rather fight than eat.” “I have licks that will carry me to my grave, and will be there till the flesh rots off my bones,” said Emanuel, adding that his master was a “devil,” though a member of the Reformed Methodist Church. But his mistress, he said, was a “right nice little woman, and kept many licks off me.” “If you said you were sick, he would whip it out of you.” From Mandrey he once fled, and was gone two months, but was captured at Williamsburg, Va., and received a severe flogging, and carried home. Hubbert finally sold Emanuel to a Mr. Grigway of Norfolk; with Emanuel Mr. G. was pretty well suited, but his wife was not—he had “too much white blood in him” for her. Grigway and his wife were members of the Episcopal Church.
In this unhappy condition Emanuel found a conductor of the Underground Rail Road. A secret passage was secured for him on one of the Richmond steamers, and thus he escaped from his servitude. The Committee attended to his wants, and forwarded him on as usual. From Syracuse, where he was breathing quite freely under the protection of the Rev. J.W. Loguen, he wrote the following letter:
SYRACUSE, July 29, 1857.
MY DEAR FRIEND, MR. STILL:—I got safe through to Syracuse, and found the house of our friend, Mr. J.W. Loguen. Many thanks to you for your kindness to me. I wish to say to you, dear sir, that I expect my clothes will be sent to Dr. Landa, and I wish, if you please, get them and send them to the care of Mr. Loguen, at Syracuse, for me He will be in possession of my whereabouts and will send them to me. Remember me to Mr. Landa and Miss Millen Jespan, and much to you and your family.
Truly Yours,
MANUAL T. WHITE. | 466 | common-pile/pressbooks_filtered | https://pressbooks.library.torontomu.ca/theundergroundrailroad/chapter/emanuel-t-white/ | pressbooks | pressbooks-0000.json.gz:91453 | https://pressbooks.library.torontomu.ca/theundergroundrailroad/chapter/emanuel-t-white/ |
t1oF13UR6WMUn8b4 | Dr. Chase's recipes; or, Information for everybody: an invaluable collection of about eight hundred practical recipes ... By A. W. Chase, M.D... | VO THl TSNTH K D I T I O IT .
Iir bringing a penuanent work, or one that is designed so to oe, before the public, it is expected of the Author that he gl.ve hia reasons for such publication. If the reasons are founded in truth, the people consequently seeing its necessity, will appreciate its advantages, and encourage the Author by. quick and extensive purchases, they alone being the judges. Then:
First. — Much of the information contained in " Dr. Chase'a Receipes; or Information for Everybody," has never before been published, and is adapted to every day use.
Second. — The Author, after having carried on the Drug and Grocery business for a number of years, read Medicine, after being thirty-eight years of age, and graduated as a Physician lo qualify himself for the work he was undertaking ; for, having oeen familiar with some of the Recipes, adapted to these oranches of trade, more than twenty years, he began in " Piflyaix," seven years ago, to publish them in a Pamphlet of only t few pages, since which time he has been traveling between New York and Iowa, selling the work and Prescribing, so that ap to tnis time, " Sixty-three," over ttoenty-three thousand cop>es have r>«>en sold. His travels have brought him in contact with ail tlasses of Professional and Business men. Mechanics. ParriPrs. and Farmers, tnus enabling him to obtain from them, many additional items, always having had his note book with hum. and whenever a prescription has been given before him, 5r a remark made, that would have a practical bearing, it has oeen noted, and at the first opportunity tested, then if good, written out in plain language expressly for the next edition of
this work. In this way this mass of information has been col< lected, and ought to take away an objection which some persons Oave raised : " It is too much for one man to know ! " because tncy did not realize that the work had been made up from other» as well as the Auther'a octudL every day experience, instead of from untried books. Yet from the nature of some of the Recipes, jue has occasionally found its way into some of the earlier editions, which have needed revision, or to be entirely dropped. This, with a desire to add to the vanous Departments, at every edition, has kept us from having it Stereotyped until the present, tenth edition.
Third. — Many of the Recipe books published are very large, containing much useless matter, only to increase the number, consequently costing too much — this one contains only about eight hundred recipes, upon only about four hundred difFerenI subjects, afl of which are valuable in daily, practical life, and at a very reasonable price — many of them are without arrangement— this one is arranged in regular Departments, all of a class being together — many of them are without remark, or explanation— this one is fully explained, and accompanied with remarks upon the various subjects introduced by the Recipes under consideration— those remarks, explanations, and suggestions accompanying the Recipes, are a special feature of this work, making It worth double its cost as a reading book, even if there was not a prescription in it
FotTRTH. — The remarks and explanations are in la/rge type, whilst the preservptive and deseripti'oe parts are in a little smaller type, which enables any one to see at a glance just what they wish to find.
Fifth. — It is a well known fact that many unprincipled per ftona go around " gulling" the people by selling single Recipe* for exorbitant prices. The Author found a thing, calling him-
■elf a man, in Battle Creek, Mich., selling a Washing-Fluid Recipe for two dollars, which he obtained of some ; but if he could not obtain that, he would take twe sliiHings, or any other sum between them. A merchant gave a horse for the " White Cement" Recipe. The late Mr. Andrews, of Detroit, Mich., ghve three hundred dollars for a Recipe, now improved and in (his work, to cure a bone spavin upon a race mare of his. He removed the spavin with it and won the anticipated wager with aer. The Author has, himself, paid from twenty-five to fifty, and seventy-five cents, and one to two, three five, and eight dollars for single items, or Recipes, hoping thereby to improve hia work ; but often finding that he had much better ideas already embodied therein.
The amount paid for information in this work, and for testing by experiment, together with traveling expenses, and cuts used in illustrating it, have reached over two thousand dollars, and all for the purpose of making a book worthy to be found in "Everybody's" library, and to prevent such extortions in the price of Recipes. Yet any single Recipe in the work which a person may wish to use, will often be found worth many times the price of the book, perhaps the lives of those you dearly love, by having at hand the necessary information enabling you to immediately apply the means within your reach, instead of giving time for disease to strengthen, whilst sending, perhaps miles, for a physician. Much pain and suffering, also, will often be saved or avoided, besides the satisfaction of knowing how many thmgs are made which you are constantly using, and also being able to avoid many things which you certainly would aixnd, if fou knew how they were made.
Sixth. — It will be observed that we have introduced a number of Recipes upon some of the subjects ; this adapts the work to all circumstances and places ; the reason for it is thia ; we havt become acquainted with them in our practice and joumeyinga, and know that when the articles cannot be obtained for one vay, they may be for some other way ; as also that one prescnption is better for some than for other persons ; therefore, ire give the variety that all may be benefitted as much aa possi*
tiii PRKPAOl
ble. For instance, there are twenty different preecriptidM for different diseases, and conditions of the eye; tiiere are also s dozen different liniments, &c., &c. ; yet the Author feels well assured that the most perfect satisfaction will be experieneed in them as a whole. And although it could not be expected that special advantages of particular Recipes could be pointed out to auy great extent, yet the Author must be indu]<^ed in reff*rring to a few, in the various Departments. All, or nearly all, Mer chant* and Grocers, as also most Families, will be more or leas beuefited by the directions for making or preserving butter, preserving eggs, or fi-uit, computing interest, making vinegar, and keeping cider palatable, &c. In ague sections of coi>ntry, none should be without the information on this subject; and in fact, Uiere is not a medical subject introduced but what will be found more or less valuable to every one; even Physicians will be more than compensated in its perusal; whilst Consumptive, Dyspeptic, Rheumatic, and Fever patients ought, by all means, to avail themselves of the advantages here pointed out. The treatment in Female Debility, and the. observations on the Changes in female life are such that every one of them over thirteen or fourteen years of age should not be without this work. The directions in Pleurisy and other Inflammatory diseases cannot fail to benefit every family into whose bands the book shall fall.
The Good Samaritan Liniment, we do not believe, has its equal in the world, for common uses, whilst there are a number of other liniments equally well adapted to particular cases. And we would not undertake to raise a family of children witb out our Whooping Cough Syrup and Croup Remedies, knowing their value as we do, if it cost a hundred dollars to obtain them Tanners and Shoemakers, Painters and Blacksmiths, Tinners ind Gunsmiths, Cabinet Makers, Barbers and Baker? will find is their various Departments more than enough, in single recipes, to compensate them for the expense of the work ; and Farriers and Farmers who deal in horses and cattle, will o*len find that Department to save a hundred times its cost in sin^lo cases
caying : " I have come ten miles out of my way to get it, for 1 staid over uight with a farmer, who had one, and had been benefitted more than $20, in curing a horse by its directions." A gentleman near this city says he had paid out dollars after dollars to c'ure a horse of spavin, without benefit, as directed by oilier books, of recipes ; but a few shillings, as directed by thia^ cured the horse. Another gentleman recently said to me: ■* Your Eye Water is worth more than $20." 1 could fill pages of similar statements which have come to my knowledge since I commenced the publication of this work, but must be content by asking all to look over our References, which have been voluntarily accumulating during the seven years in which the work has been in growing up to its present size and perfection ; and the position in society, of most of the persons making these statements is such, many of which are entire strangers to the Author and to each other, that any person can see that no possible complicity could exist between us, even if we desired it
Families will find in the Baking, Cooking, Coloring and Miscellaneous Departments, all they will need, without the aid ot any other " Cook Book ; " and the Washing-Fluid, which we have used at every washing except two for nearly eight years, is worth to every family of eight or ten persons, ten times the cost of the book, yearly, saving both in labor and wear of clothes.
Seventh.— Many of the articles can be gathered from garden, field or woods, and the others will always be lound with Druggists, and most of the preparations will cost only trum mu-hnlf to as low as ane-sivteenth as much as to purchase them already made ; and the only certainty, now-a-days, of having a grjod aiticle, is to make it yourselC
Fenallt.— There is one or two things fact about this book ; It is the biggest humbug of the day; or it is the best work of the kind, published in the English language. If a careful perusal does not satisfy ali that it is not tJu first, but that it is the last, then will the Author be willing to acknowledge that Testing, Experimenting, Labor, Travel and Study, to be of no account in qualifying a man for such a work, especially when that work h«ia been the long cherished object of his life, for a lasting bene-
C FEKPAOI
fit to hi* fsllow creaturea, S8\ing them from extortion, In buying single i€cipefl, and alio giviiig them a reliable work, for every emergency, more th in fof tus own pecuniary benefit. Were it not so, I should have Rept iue work smaller as heretofore, for the eighth edition of two hundred and twenty- four pages when handsomely bound sold for One Dollar, but in this edi-
tion you get a Dollar's worth of book, even if common reading Oiatter, besides the most reliable practical information, by which you will cften save, not only doUars and cents, but relieve suffering and prolong life. It is, in fact, a perfect mass of the mosi valuable methods of accomplishing the things spoken of, an Encyclopedia upon the various branches of Science and Art, treated of in the work, which no family can afford to do without ; indeed, young and old, " Everybody's" book. And the " Taxes" nor " Times" should be, for a moment, argued against the purchase of so valuable a work, especially when we assure you thai the book is sold only by Traveling Agents, that aU may have a chance to purchase ; for if left at the Book Stores, or by Advertisement only, ru)t One in Mfty would ever see it.
Some persons object to buying a book of Recipes, as they are constantly receiving so many in the newspapers of the day, but if they had all that this book contains, scattered through a number of years of accumulated papers, it would be worth ma^ than the price of this work to have them gathered together, carefully arranged in their appropriate departments, with an alphabetical index, and handsomely bound ; besides tl»e advantage of tbtir having pap«ed under the Author's carefully pruning and grafting hand.
" To uproot error and do good should be the first and highest aspiration of every intelligent being. He who labors to promote tb. physical perfection of his race — he who strives to make mankind intelligent, healthy, ana happy — cannot fail to have reflected un his own soul the benign smiles of those whom he has been the instrument of benefitting." The Author has recieved too many expressionn of gratitude, thankfulness, ana favor, in regard to the value of " Dr. Chase's Recipes; or Infor mation for Everybody," to doubt in the least, the truth of tn( foregoing quotaiion: and trusts ^at the following quotatinq
May these reasons speedily become the governing principloa tnfoughout the world, especially with all those who have taken upon themselves the vows of our "Holy Religion;" knowing that it. is to those only who begin to love God, and right actions, her«, with whom the glories of Heaven shall ever begin. Were they thus heeded, we should no longer need coroboratiug testimony to our statements. Now, however, we are obliged to array every point before the people, as a Minor, that they may judge uTider standingly, even in matters of thomost vital imporAnce to themselves ; consequently we must Ite excused lor thia engthy Preface, Explanatory Index, and extended I?eferencea following it. Yet, that there are some who will let the work go by them as one of the " Humbugs of the day," notwithstanding all that has or might be said, we have no doubt ; but we beg to refer such to the statement amongst our References, of the Rer. C. P. Nash, of Muskegon, Mich., who, although he allowed it thus to pass him, could not rest satisfied when he saw the reliatbility of the work purchased by his lesn incredulous neighbors ; then if you will, let it go by ; but it is hoped that all purchaser* may have suflScient confidence in the work not to allow it to lay idle ; for, that the designed and greatest possible amount <rf good shall be accomplished by it, it is only necessary that it should be generally/ ir^jpodueed, and daHjf uted, is the positive knowledge of the
Vinegar, in Three Weeks — in Barrels without Trouble — E'rom Sugar, Drippings from Sugar Hogsheads, &e., —From Acetic Acid and Molasses — From Apple Cider— la Three Days, Without Drugs — Quick Process by Standing upon" Shavings, 39-40
SALOON DEPARTMENT.
Apple Cider; to Keep Sweet with but Trifling Expense — To Prepare for Medicme — Artificial Cider, or Cider WiUiout Apples ; to ilake in Kegs or to Bottle, or i»? Barrels, for Long Keeping, with Directions About
Syrups ; to make the various Colors — Syrups Artificial ; vailbus Flavors, as Raspberry, Strawberry, PineApple, Sarsaparilla, »&c. — Lemon Syrup ; Common— Lemon Syrup ; to save the loss of Lemons — Soda
Wines ; Currant, Cherry, Elderberry, and other Berry Wines — Rhubarb, or English Patent Wine — Tomato Wine — Wine from white Currants — Ginger Wine, — Blackberry Wine — Port Wine — Cider Wine — Grape
Ague Medicines ; Dr. Krider's Ague Pills — Ague Bitters — Ague Powder — Ague Mixture, without Quinine — Ague Cured for a Penny — Ague Anodyne — Tonio Wine Tincture, a positive cure for Ague without Quinine, 77-80
Alterative Syrup, or Blood Purifier— Alterative ; very strong — Alterative Cathartic, powder— Alterative for Diseases of the Skin — Alterative, Tonic and Cathartic, Bitters, 14»-148
Bums; Salve for Burns, Frost-Bitcs, Cracked Nipples, »!cc. ; very successful, — Dr. Downer's Salve for Burns, — Poultice for Burns and Frozen Elesli, — Salve from the Garden and Kitciien, for Burns, ei^ti preparations, 110-11)
Cancers, to cure, Methods of Dr. Eandolfi (Snrccon General to the Neapi>litan Army,) — Dr. II. G. dudkins'— L. S. lIodgkin.s'— Kev. C. 'C. Cuylers'— Great ' English Hemedy — American, Red Oak Bark, Salvo fn)m the Aiihes — I'rof. K. S. Newtou's — Prof. Calkins". t «tec., altogether fourteen prescriptions, ^Yith Cautions against the use of the Knife, showing when the Treatment should commence, «fcc., 9*J -lOU
Cod Liver Oil, made Palatable and more Digestible, . . . 119
Consumptive Syrup, very successful, with directions about Travel — Remarks on tho Use of Fat Meats aS Preventive of Consimiplion, Ac, — Chlorate of Potash in Consumption, new renaedy — Itational Treatment for Consumption, claimed to be the best in the world 119 126
Cough Lozenges, two preparations — Pulmonic Wafers for 'Joughs— Coughs from Recent Colds, remedyCough jyii,\ture for Recent Colds— Cough CandyCough Syrup— Cough Tincture— Cough Pill, ni>-l'J^
Carminatives, for Children, 182
Dyspepsia; Treatment from Personal Experience, witb Cautions about Eating between Meals, especially against Constant Nibbling; also Father Piukney's
Diarrhea Cordial — Injection for Chronic Diarrhea — Diarrhea Tincturo, Drops and Syrup ; also for Flux and • Chronic Diarrhea in Adults and Children, when accompanied with Canker, 17&-178
Kclectic Emetic, 105
iSye Water — often acknowledged to be worth mote than Twenty Dollars — India Prescription for Sore Eyes — Dr. Cook's Eye Water — Preparation for excessive Inflammation ot the Eves— Sailor's Eye Preparation -Father Pinkney's P'^paration for very bad Sore Eyes — Indian Eye Wuver — Poultices for the Eve — Films, to remove from the Eye — Eye Salve — Sore Eyes, to remove the Granulations — Altogether, twenty-two Prescriptions, for diflerent conditions oi
Fevers ; General improved Treatment, for Bilious, Ty- j phoid and Scarlet Fevers, Congestive Chills, «&c. ; >; also valuable in arresting Diarrhea, Summer Complaint, Cholera-Infantum and all forms of Fever ia Children — Lemonade, nourishing for Fever Patients — Prof. Hufeland'8 Drink for Fever Patients, or for excessive Thirst 80-87
Fever-Sore Plaster or Black Salve; has saved two different Hilnds that two different physicians, in each case, said must be cut off-.Red Salve for Fever-Sores— Indian Cure for Fever Sores— Kitridge's Salve f©r FeverSores— Fever-Sore Poultices, Oiutments, and Salve for Fever-Sores, Abscesses, Broken rjrcasts, &c., eleven preparations, 159 161
Female Debility and Irregularities, Explanations and Treatment — Female Laxative Pills — Female Laxative and Anodyne Pills — I'ills for Painful Menstruation — Injection lor Female ComplaintsPowder for excessive
Inflammation of the Throat, (Laryngitis) — Gargle for Sore Throat — Sore Throat Liniment, with a {synopsis, (general view), of Dr. Fitch's Treatment of Throat Dispsses, 92-Vo
Inflammation of the Lungs— Inflammation of the Pleura, (pleurisy), with such full explanations 0f general Inflammations that no dilticulty will be experienced in Treating the Disease in any of its forms, 195-208
[nflammation of the Liver — Eclectic Liver Pill — Liver Pili, Improved — Liver Drops, for obstinate cases — Ointment for Ulcerated Liver, Ague Cake, &c. ; very pucccssful, 146- 1 47
Liniments; Good Samaritan, Imjjroved — Liniment for Old Sores— Dr. Raymond's Liniment— German Rheu matic Liquid or Lmiment— Cook's Electro-Magnetic Liniment — Liniment for Spinal Aflections — Great Loudon Liniment — Gum Liniment — Patent Liniment — Lobelia and Cayenne Liniment — Liniment, said to b« St. John's &c,. 114-118
Ointment for Old Sores — Mead's Salt-Rheum Ointment ; has proved very successful — Judkin's — Sisson's Green Ointment — exceedingly good — Dr. Kittredge's 'celebrated Ointment for '-Pimpled Face," "Prairie Itch," &c., — Dr. Gibson's Ointment, for very bad Skin Dfceaees — Itch Ointment — Magnetic Ointment, said to be T rask'9, with Stramonium Ointment and Tincture
Uheumalic Liniment — Inflammatory Rheiunatism; to cure — Dr. Kittredge's Remedy for Rheumatism and Stiffened Joints, from Rheumatism — French Remedy for Chronic Rheumatism — Bitters for Chronic Rheumatism ; very successful ; Green Bay Indian's Remedv for Rheumatism — New Remedy, &c. ; iioetoe preparations, 135-138
Sick-Headache; to cure — Periodical Headache — Headache Drops — Tincture of Blood-root for certain Headaches— Charcoal for certain Headaches, 104-107
Teeth ; Extracting with little or no Pain — Tooth Powder ; Gxcellent — Teeth ; to remove Blackness — Tooth Cordial ; Magnetic — Homeopathic Tooth Cordial — Neuralgia ; internal Remedy— King of Oils, for Neuralgia and Rheiunalidm '. 184-18?)
Tanning Sheep Skins; applicable for Mittens, DoorMats, R'Jbes, &c., — Tanning Fur and other Skins; Fifty Dollar Recipe — Tanning Deer and Woodchuck Skins, for Whips, Strings, &c., — Process of Tanning Calf, Kip and Harness, in from Six to Thirty DaysCanadian Process also, with Mr. Rose's modification,
Chrome Green— Chrome Yellow — Green ; durable and Cheap — Paris Green; two processes — Prusian Blue; two processes — Pea Brown — Rose Pink, 232-238
Iron or Wood; to Bronze, Representing Bell-metal, . . 241 Mill Picks ; to Temper; three Preparations — Mill Picks and Saw Gummers; to Temper — Mill Pick Tempering, as done by Church, of Ann Arbor, 236 237
superior to the Patent Trusses, 241
Varnishes ; Transparent ; for Tools, Plows, «&c. — Varnish ; Transparent Blue, for Steel Plows — Varnish, Seek-No-Further, for Iron or Sleel — Varnish ; Black,
Linimeui for SlilJ Necks, from Poll-evils— English J>ta ble Liuimeul, Very Strong— Liniment for One Shilling a Quart, Valuable iu Strains, Old Swellings, &c. ;
Poll-Evil and Fistula, Positive Cure — Poll-Evil and Fistula, Norwegian Cure ; Eight Methods, all of which have Cured Many Cases — Poll-Evils, to Scatter, &c. ;
ftmg-bone and Spavin Cure, often acknowledged worth the Value of the Borse— O. B. Bangs' Method for Recent Cases — llawson's Ring-bone and Spavin Cure, has Cmed Ring-bones as Thick as the Ai"m — Indian
I'olish ; for New Furniture — Polish ; for reviving Old Furniture ; equal to the " Brother Jonathan,' and Polish for removing Stains, Spots and Mildew from Furniture, 269-270
Stains; Mahogany on Walnut as Natural as Nature — Rose Wood Slain; Very bright Shade, used cold — Rose- Wood Stain; light Shade, used hot — Rose-pmu, Slain and Varnish; also used to imitate Rose- Wood —
Kair Restorative; equal to Wood's, for a Trifling cost; four preparations; cheap and Reliable — Hairlnvigorators, tiioo preparations; will stop Haii ^om Falling 27&-276
Breads ; Yankee Brown Bread — Graham Bread — London Baker's superior Loaf Bread— New French Method of making Bread — Old Bachelor's Bread, Biscuit and Pie-Crust — Baking Powders, for Biscuit, without Shortening, 290-i«W}
fakes ; Federal — Rough and Ready — Sponge Cake, with Sour milk — Sponge Cake, with Sweet Milk — Berwick Sponge Cake, without Milk — Surprise CaKe — Sugar Cake — Ginger Cake — Tea or Cup Cake — Cake without Eggs or Slilk — Pork Cake, without Bntier, MUft or Eggs — Cider Cake — Ginger Snaps- -J ell Cake and, Roll Jell Cake- -Cake Table, showing how to make Fifteen different kinds, as Pound, Genuine Whig, Shrewsburry, Training, Nut Cake, Short, Cymbals. Burk, and Jumbles, — Ginger Bread, — Wonders,—' Cookies — York — Biscuit — Ck)mmon and Loaf CakesMolasses Cake — Marble Cake — Silver Cake, and Gold Cake, fiuisin^ with Bride and Fruit Cakes — Frosting for Cakes, &c. — Excellent Crackers — Sugar Crackers—Naples Biscuit — Buckwheat Short-cake, ^vithout Shortening, most excellent ; and Y'east Cake, . . . 281- 2^
Pies; Lemon Pie, extra nice — Pie-Crust Glaze, which prevents the juices from soaking into the crust— Ap>ple-custard Pie, the nicest ever eaten— Paste for Tarts, 293-206
Puddings; Biscuit Pudding, without Re-baking— Old English Christmas Plum Pudding— Indian Pudding ; to Bake — Indian Pudding, to Boil — Quick Indian Pudding — Flour Pudding, to boil— Potatoe Pudding— Green Corn Pudding — Steamed Pudding — Spreading and Dip Sauces for Puddings, 295-29?
fourth the Expense of Common, 834
Cements ; Cements for China, &c., which Stands Fire and Water — Cement, Cheap and Valuable — German and Russian Cement — Cement, Water Proof, for Cloth and Belting — Cement or Furniture Glue, for House Use — White Cement and Cement to prevent Leaks about Chimneys, Roofs, &c. — Scrap Book Paste or
Meats; to Preserve — Beef; to Pickle for Long KeepingMichigan Farmer's method — Beef; to Pickle for Wm ler or Present Use, and for Drying, very nice — Mutton Hams; to Pickle for Drying — Curing, Smoking and Keeping Hams— T. E. Hamilton's, Maryland Premium method— Pork; to have Fresh from Winter Killing, for Summer Frying — Salt Pork for Prying; Nearly Equal to Fresh — Fresh Meat ; to Keep a Week or Two, in Bummer — Smoked Meat ; to Preserve for Years or for Sea Voyages — Rural New Yorker's Method, and the New England Farmer " Saving his Bw^on," 309-811
Starch Polish 329
Soaps ; Soft Soap, for Half the Expense and One-Fourth the Trouble of the Old Way — German Erasive Soap — Hard Soap — Transparent Soap— One Hundred Pounds of Good Soap for One-Dollar and ThirtyCenta— Chemical Soft Soaj>--Soap Without Heat — Windsor or Toilet Soap — Variegated Toilet Soap, &c., 304-306
WHITEWASH AND CHEAP PAIKT8.
Brilliant Stucco Whitewash ; Will Last on Brick or Stone, Twenty to Thirty Years — Whitewash ; Very Nice ^or Rooms — Paint; to Make Without Lead or Oil — White Paint; a New Way of Manufacturing — Black and Green Paint ; Durable and Cheap for Out- . Door Work— Milk Paint; for Bams, Any Color, 325-328
Dark— Snuff Brown— Madder Red— Oreen on Wool cr Silk, with Oak Bark— Green, with Fustic— Blue; Quick P*rocc88 — Stocking Yam or Wool; to Color Between a Blue and Purple — Scarlet with Cochineal, for Yun or Cloth— Pink— Orange— Lac Red— Purple—Silver Drab ; Light Shade— Slate ; on Woolen or Cotton— Extract of Indigo or Chemic,"u8ed in Coloring; to Make — Wool; to Cleanse — Dark Colors; to Extract and Insert Lierht, 848-84fl
Jurable Colors on Cotton; Black— Sky Blue— Lime Water and Strong Lime Water ; to Make for Coloring Purposes — Blue on Cotton or Linen, with Logwood — Green— Yellow — Orange — Red — Muriate ef Tin, Liquor ; to Make, 847-84B
Dolors for Silk; Green; Very Handsome, with Oak Bark — Green or Yellow, on Silk or Woolen ; in Five to Fifteen Minutes Only— Mulberry— Black — Spots; to Remove and Prevent Spotting when Coloring Black on Silk or Woolen— Light Chemic Blue — PAUT)le — Yellow — Orange— Crimson — Cinnamon or Brown — on Cotton and Silk, by a New Process ; very Beautiful, S49-35)
Interest Tables, Showing the Interest at a Glance : At Six, Seven, Eight, Nine, and Ten Per Cent, on all Sums from One Dollar to One Thousand Dollars, From One Day to One Year, and for Any Number of Years ; Also, Legal Literest of all the Different Stales, and the Legal Conseguences of Taking or Agreeing upon Usurous Rates m the Different States 852-8W
GL08SARIAL, EXPLANATORY, DEPARTMENT.
This Department embraces Tables of Rules for Administering Medicines, Having Reference to Age and Sex — Explanations of MedicaJ Abbreviations, Apothecaries Weights and Measures — also, an Explanation of About Seven Hundred Technical Terms found in Medical Works, Many of which are Constantly Occurring m the Common Writings and Literature of the Day, which are not explained in English Dictionaries,. . . . 361-884
Possession, Connected with his Study of IMedioine.
" I hereby certify that A. W. Chask haa prosecuted the Study of Medicine under my instruction during the term of two years aod sustains a good moral character.
Eclectic Medical Ihstitutb, Cin., O. Bjiow All Men by these Presents, That A. W. Chase has sustained an honorable examination before the Faculty of this Institute, on all the departments of Medical Science, «&a * * Wherefbre we, the Trustees and Faculty, * * » by the authority vested in us by the Legislature of'^the State of Omo,do confer on him the Degree of Doctob of Medicine.
ANN ARBOR REFERENCES.
f- The following statements are given by my neigTibora, to whom I had sent the eighth edition- of my " Recipes," asking their 'Opinions ofltAvalue for the people, most of whom had previous'ly purchased earlier editions of the work, and several of them 'nsed many of the Recipes ; and surely their position in'scKsety must place their statements above all suspicion of complieity vrith ,the author in palming off a worthless book ; but are designed to henefii tht people by increasing the spread of genuine praetioai [information :
Hon. Alphkub Fblch, one of our first lawyers, formerly % Senator in Congress, and also ex-Gtovemor of Michigan, says : — ■PleaseTMXjept my thanks for the copy of your *' Recipes," which you were so good as to send me. The book seems to me to sont&in rmieh uduable yiraetical informatum, and I have no doattf prill be extensively usefuL
A. WiNOSEiiL, Profeesor of Geology, Zoology and Botany, In the University of Michigan, and also State Geologist, says : — I have examined a large number of Recipes in Dr. Chase's published collsction, and from my knowledge, either experimental or theoretical, of many of them, and my confidence in Dr Chase's carefulness, judgment, and conscientiousness in the selection of such only as ure proved useful, after full trial, I feel no hesitation in saying that they may all be received with the utmost confidence in their pracGcal value, except in those cases, where the Doctor has himself qualified his recommendations.
Jamks C. Watson, formerly Professor of Astronomy, and now Professor of Physics, In the University of Michigan, author of a " Treatise on Comets," also of " Other Worlds, or the Wonders of the Telescope, " says : — I have examined your book of practical Recipes, and do not hesitate to say that so»far as my observation and experience enable me to judge, it is a work which should find its way into every family in the land. The information Vhich it contains could only have been collected by the most careful and long continued research, and is such as is required in every day life. I can heartily recommend your work to the patronage of the public.
Rev. L. EJ, Chapen, Pastor of the Presbyterian Church, says: Allow me to express to you my gratification in the perusal of your book. I do not regard myself as qualified to speak in re-
fard to the whole book, for you enter into Departments in which have no special knowledge, but where I understand the subject I find many things of much practical value for every practical man and house-keeper: and judging of those parts which I do not, by those which 1 do understand, I think that f ou have furnished a book that most families can afford to have at any reasonable price.
Rev. Geo. Smith, Presiding Elder of the M. K Church, Ann Aj-bor, says : — I take pleasure in saying that so far as I have examined, I have reason to believe that your Recipes are genuine, and not intended as a catoh-penny, but think any person Tiurchasing it will get the worth of their money.
Rev. Geo. Taylor, Pastopof Ann Arbor and Dixboro M. K Church, writes as follows: — As per your request, I have carefiil!y examined your book of Recipes, recently issued, and take pleasure in adding my testimony to the many you have already received, that I regard it as the best compilation of Recipes have ever seen. Several of these Recipes we have used in out family for years, and count each of them worth the cost of your book.
Elder Samuel Coknelius, Pastor of the Baptist Church, writes: — I have looked over your book of "Infopnation for Everybody," and as you ask my judgment of it, I say tlmt it gives evidence of much industry and care on the part of the oompUer, and containB iuformaUoa whjrii must b« valuable to
all classes of business men, In toMTi and country, and especially to all families who want to cook well, and Lave pleasant, healthy drinks, syrups and jellies; who wish to keep health when they enjoy it, or seek for it in an economical way. I thank you for the cojiy you sent to me, and hope you may make a great many familiet healthy and happy.
Rev. F. a. Blades, of the M. E. Church, and Pastor in charge^ for two years, of Ann Arbor Station, says : Dr. Chase — Dear Sir— Your, work of Recipes, I have examined — and used some of them for a year past — I do not hesitate to pronounce it a valuable work — contaming information for the Million. I hope yon will succeed in circulating it very generally — it is worthy a place in every bouse.
Eqkrbach & Co., Druggists, of Ann Arbor, say: — We have been filling prescriptions from " Dr. Chase's Recipes," for three or four years, and freely say that we do not know of any dissatvffaciion arising from want of correctness ; but on the other hand, we know tiiat they give general satisfaction.
Rev. S p. Hildreth, of Dresden, O., a former neighbor, inclosing a recent letter, says: I have carefully examined your book, and regard it as containing a large amount of Information which will be valuable in every household.
Rev. William C. Wat, of the M. E. Church, Plymouth, Mich., Bays; — I have cured myself of Laryngitis, (inflammation of the throat,) brought on by long continued and constant public speaking, by the use of Dr. Chase's black oil, and also know a fever sore to have been cured upon a lady, by the use of the same article.
OPINIONS OF THE ANN ARBOR PRESS.
A Nfw book. — Dr. Chase, of this city, has laid on our table a new edition of his work entitled " Dr. Chase's Recipes, or Information for Everybody," for making all sorts of things, money not excepted. We would not, however, convey the idea that the Doctor tells you how to make spurious coin, or counterfeit bills, but by practicing upon the maxims laid down in this work, money-making is the certain result. Buy a book, and
adopt the recipes in jour households, on your farms, and in your business, and success is sure to follow. The work is neatly printed, elegantly bound, and undoubtedly embodies more useful information than any work of the kind now before the public.
Students, or others, wishing to engage in selling a saleable work, will do well to send for circulars describing the book, with terms to agents, &c., for it is indeed a work which " Everybody " ought to hove. — Michigtm 8((Ue Netoa, Arm Arbor.
Db. a. W. CHABB.of this city, has pl&ced on our table a copy of his " Recipes, or Information for BSverybody." Beginning with a small pamphlet, the Doctor has swelled his work to a bound volume of about 400 pages; an evidence tha* ais labors are appreciated. The volume nvmishes many re^^ipes and much information of real practical value. — Michigan ^rgu«, Ann Arbor.
Dr. CHASE'S RECIPES.— The ninth edition of Dr. Chase's Recipes has been recently published, revised, illustrated and enlarged,— comprising a very large collection of practical information for business men, mechanics, artists, farmers, and for families generally. The recipes are accompanied with explanations and comments which greatly increase the value of the wort. It ii a handsomely bound volume, ->-'^ v'^ •. — Ann Arbor JoumaL
Dk. chase, of Ann Arbor, has favored us with a copy of his book of recipes, which has, in an unprecedented short time, reached the ninth edition, showing its popularity wherever it has been ini,roiluced. It contains " information for everybody," for making all sorts of things. It is a valuable work for every on<*— many single recipes being worth much more than the cost of the book. Rev. Mr. Frazer, the gentlemanly agent for the work, is now in the city, and will call upon our citizens eiving them an oppprtunitv to secure a copy. The work is neatly pnnted, elegantly bound, and undoubtedly embodies more usefhl information than any work of the kind now before the public.
Dr. chase, of Ann Arbor, has favored us with a copy of Recipes which he has published, * * * * who claims that they have been made up from his own and others' every day expenence. There are certainly a great many useful recipes in this work that might be found to richly repay its cost to any family. — Michigan Farmery Detroit.
The following wholesale dealers of Detroit, and others with whom I have dealt for years, say : — We have been acquainted with Dr. A W. Chase for several years in the Drug and Groceiy business, and we are well satisfied that he would not do a business which he did not know was all right. His information in ♦iie furiD of recipes can be depended upon.
Was first built in 1864, (22x70 feet, four stories, including the basement, which is used for the Press-room), mainly for the purpose of enabline the proprietor to meet the increasing demand for "Dr. Chase's Rkcipks," at which time one-half of one story gave ample room for one Department of the business. But in 1865 he purchased the Peninsular Courier, and began to do
Adopting the motto— good work for the least possible price — it soon became necessary to occupy the whole of one story for each branch or Department; and ultimately finding our rooms to small for the work demanded at our hands, in the summer of 1S6S, we made an addition of 40x70 feet, finishing each story in one room, the Bindery, Compositors, Press-room and Office being each 39x68 feet, putting in a 22 horse Boiler and Engine, one of Hoe's largest "Jobbers," upon which a sheet 39x56 inches can be printed — no other Press in tne State equal to it in size, — also another large Adams' Book Press, upon which sixteen octavo pages can be worked, (while nearly all other Western printmg establishments can only work eight pages, our press-work costing only one-half as much as theirs), with much other macninery and furnishing employment for OVER FORTY HANDS, and
URGEST, CHEAPEST, AND BEST FAMILY NEWSPAPER IN THE STATE
In proof of this assertion we have only to state that at the time of its purchase the circulation was less than 300, now OVER SIXTEEN HUNDRED coT^'\e.s, (beitiff more than double that of any other fafer in the County,) and our subscription list is constantly increasing. — Devoted to News, Politics, Temperance, Morality and Religion — Soundly Republican, alive, in all its Departmen**,
VlNEGrAR. — Merchants and Grocers who retail vinegar ahould always have it made under their own eye, if possible, from the fact that so many unprincipled men enter into its Manufacture, as it affords such a large profit. And I would fiirther remark, that there is hardly any article of domestic use, upon which the mass of the people have as little correct information as upon the subject of making vinegar. I shall be brief in my remarks upon the different points of the subject, yet I shall give all the knowledge necessary, tha families, or those wishing to manufacture, may be able tc have the best article, and at moderate figures. Remembci this fact — that vinegar must have air as well as warmth, and especially is this necessary if you desire to make it in a short space of time. And if at any time it seems to be " Dying, " as is usually called, add molasses, sugar, alcohol, or cider — whichever article you are making from, or prefer — for vinegar is an industrious fellow ; ho will either work or die, and when he begins to die you may know he haa worked up all the material in his shop, and wants 'more. Remember this in all vinegars, and they will never die, if Uiey have air. First, then, upon a small scale, for family ise.
To Make in Threk Weeks. — Molasses 1 qt. ; yeast 1 pt. ; warm rain water 3 gals. Put ali into a jug or keg, and tie a piece of gauze over tlie bung to keep out flies and let in air. In hot weather set it in the sun ; in cold weather set it by the stove or in the chimney corner, and in three weeks you will have good vinegar.
never have trouble for want of good vinegar.
2. A con-espondent of tlie Dollar Newspaper says: "Th« cheapest mode of making good vinegar is, to mix 5 qts. of warm rain water with 2 qts. of Orleans molasses, and 4 qts of yeast. In a few weeks you will have the best vinegar you ever tasted." He might well say, " The best vinegar you ever tasted," for it would have double the necessary strength, and three or four times the strength of much that is sold ; yet this strength "would cost less to make, than to buy by the quart.
3. In Barrels Without Trouble. — Merchants and Groeers, who retail vinegar, can always keep a good supply on hand by having about two or three barrels out of which to sell, by filling the first one they sell out, before quit* empty, with
Keeping this proportion to fill the barrel ; the vinegar and mother which is left in the barrel makes it work much quicker than if put into empty barrels ; so pass around on ■ho next barrel as it is nearly out, having three barrels, and anless you sell more than a baxrel a week, you need nevei oe out of vinegar. Some recommend to use alum, creani of tirtar. <tc., in vinegar, but / say, never. It is always advisable to have a hole in the top of the barrel, if standing on end; if on the side, the bung out and a gauze over it, to keep out flies aiul let air in.
4. From Sugar, Drippings from Sugar Hogsheads, Ac. — Dealers who retail mola.sses, often have from five to fifty pounds of sugar left in the barrel after selling out the molasses. Each pound of this, or other sugar, dissolved in two gallons of soft water, makes that amount of good vinegar by either of the above plans. Rinsings of molasses barrels or drippings of sugar hogsheads brought to this degree of sweetness, is as good for vinegar as any other material. Small beer, lager beer, ale, &c., which have become sour, make good vinesrar bv reducing with water; small beer will need but little water ; lager beer will need as much water as beer, or a little more ; and ale, twice aa muclx water aa ale ; they will all need yeast, a quart or two t» each barrel, unless put into barrels which have some vin-
cess in all cases if there is vinegar in the barrel.
5. Fkom Acetic Acid akd Molasses. — Acetic acid 4 lbs; molasses 1 gal. ; put them into a 40 gallon cask, aud fill it up with rain water ; shake it up and let stand from one to three weeks, and the result is good vinegar.
If this does not make it as sharp as you like, add a little more molaases. But some will object to this because an acid is used: let me say to such, that acetic acid is concentrated vinegar. Take 1 lb. or 1 pt. or any other quantity of this acid, and add seven times as much soft water, and you have just as p;ood vinegar as can be made from cider, »nd that xnstanta/Keousli/.
6. Fro»i Apple Cider. — As there are those who will not have any bi'.t cider vinegar, and have plenty of cider out of wVich to make it, I will give you the best plan of proceeding for manufacturers :
Have a loom where it will not freeze ; place on end as many barrels or large casks, witho ut heads, to hold as much as you wish to m«ke T £ill these one-third full of soft water, and the oilier two i,hirds with apple cider ; yeast 2 q is. to each cask.
In a fe»< weeks you will have good vinegar j without the yeast it wuuld be all the season in becoming good. Then fill up into barrels for sale, leaving a little, say one-eighth, in the opt^a barrels, and fill them up with water and cider as before, and it will become good much quicker than before. If bhe water is objected to, use the cider without it, but pure cider makes vinegar too strong for any one to use, and requires much longer time in making. These barrels may havo boards over them to keep out flies and dirt. If the reuiier can give it his attention, by having a barrel of good cider vinegar to sell out of, he can always koep it up, if, when ue draws out two or three gallons of the vinegar, he will go to his cider, kept for the purpose, and replaee the vinegar with the cider ; or if making with molasses and water or any other article, fill up with the same ; but take notice, if you forget or neglect, and draw your vinegar nearly all out before you fill in, it does not keep to the point of sharpness desired, unless you have two or three barrel* as mentioned in recipe No. 8
Persons who hav« old sour cider on hand can in this way, or as mentioned in No. 6, have good vinegar from it immediately, as it comes around into vinegar much quicker tha3 new cider.
7. In Three Days avithout Drugs, — The philosophy of making vinegar quickly, is this : The means that will expose the largest surface of the vinegar fluid, of a certain temperature, to the air, will convert it into vinegar in the shortest time ; and as there is no way by which so great a surface can be exposed as by the shavings process, and at the same time control the temperature, that plan has been adopted, as explained in the wood cut accompanying, and in th* descriptive note :
through it, ,
Outer portion of the tub, which should be fllK-il witli the sliavings to within an au iucb or two of the false top
Vinegar Gekkratob.
i^EBCRiiTivE Note. — Tdosc wishing to manufacture, to sell at wholesale , will prepare a tub, or square box, and arrange it aa shown in the accompanying cut, knowing that the taller and larger the tub, the quicker will the vinegar become good. The air holes are bored through every other, or every third stave» around the whole tub. These holes are to be about one foot oi eighteen inches from the bottom ; they must also be bored slanting down as you bore inward, othe-nise the vinegar would run out and waste as it drips down the side of the tub. Now take beech ma'ile oi
basswood boards — and they are valuable in the order namedcut them off about eighteen inches in length, and plane thick, heavy shavings from the edges ; and if they do not roll up and Btay in nice rolls, you must roll and tie them up with small cord , or clean corn cobs will do, but they will only last one season, whilst the shavings will last several years. If cobs are used, they must be put in lij^yers, each layer crossing the other, to pre vent their packing too close. Then wet or soak them thorough ly in water, and till up llie tub or tubs with them, unti". you ait within two or three feet of the top, at which place you will nai a stout hoop around, upon the inside of the tub, which shall support the false top, which has been made and fitted for that purpose, through which false top you will have bored good sized gimlet holes about every two inches all over its whole surface, through each of which holes a small cord, about four or five inches in length, is to be drawn, having a knot tied upon its upper end to keep it in its place, and to prevent the vinegarfluid from working out too fast. The size of these holes, and the size of the cord, must be such as to allow the amount ol vinegar being made to run tlu'ough eveiy twelve hours, or it time can be given to put it up so often, it may run through every six hours. You will cork all around between the false top and th« tub witli cotton, which causes the vinegar-fluid, hereafter to be described, to pass through the gimlet holes and drip from the en is of the fuuiII cords, evenly, all over the shavings, otherwise, i*" the false top was not exactly level, the vinegar-fluid n'ould all run off at tiie lowest point, down the side of the tub, apd be a very long time in becoming good, whilst if it drips slowly and all over and down tlirough the shavings, it soon comes around into good viiicgai The holes bored for that pur p( se, i^ warm weather, oxidizes or ncctifies the vinegar-fluid, by aford'ug the <?co essential points of quicKiy making good vinegar, that i'', air and heat, without the expense of a fire to warm the fluid, or room in which the vinegar is made. Now bore five oiie-iMch holes through the false top, one of them through the center, and the others two-thirds of the distance each way, lowRrds the outside of the tub, into which holes drive as many pins, having a three-quarter inch hole bored through them lengthwise, which makes them tubes ; cut the tubes off' an inch br'ow the top of the tub, so as to be out of the way of the main c( ver or loose boards which will be thrown over the top of the It b for the purpose of keeping out flies and dirt, and also to keep the heated ai; in, which comes up through the tubes ; thia ai** becomes heated by the chemical action of the air upon the i^inegar fluid as it drips along down through the shavings in the Uit), becoming so hot that it would be uncomfortable to hold the hand therein. The space between the false top and the covei is railed the vinegar fluid space; and it must be sufficiently tight til tiic joints of the tub, or box, to hold the fluid when put in. Now taJie a barrel of good vinegar and pour it into the top oi
the tub, and let it drip through the gimlet holes, from* the cords, over the shavings, two or three times, each time putting in one gallon of highwiues, or two or three gallons of cider, as the case may be, wliich sours the shavings and greatly helps the starting process of the vinegar-making. Without the addition to the strength of the vinegar as it runs through, it would part with nearly all of its own strength or acidity, to the shavings and thus lose its own life. If you have not, nor cannot obtain, vinegar, to start with, you must begin with weak vinegar-fluid, and keep adding to it every time tliroufih until it becomes very sour ; then you will consider yourself ready to begin to make vinegar in double quick time, by using any of the fluids mentioned in the foregoing vinegar recipes. But manufacturers generally use highwiues thirty to forty per cent above proof, one gallon ; water, eleven gallons ; but persons living a great distance from market will find a cheaper plan by using ninety eight per cent alchol, one gallon ; water fifteen gallons ; either of which make good vmegar, using yeast ot course, with either article, from one pint to one quart to each barrel being made. Another tub or vat must be se'u in the ground, imder the generator, or in a cellar, as the case may be, to hold as much vinegar as the space between the false and real top will contain, or as much as j'ou wish to make at one time; from Avhich it is to be carried up in buckets, (or a wooden pump having a leather sucker is quicker and easier to raise it,) to the top of the generator until it becomes good vinegar, which it will do in the time mentioned at the head of this recipe, if passed through the generator by the faucet every twelve hours which it must be ; and if the tubs are fifteen or twenty feet high, it will only need passing through once, or twice at most.
Some Avill have no vinegar but that made from apple cider; then put in one-third water, and it makes vinegar as strong as anybody ought to use ; but if they will have it at full strength, make it so, only it requires a little longer time to make.
If those who have cider which has been standing a long time, and does not become vinegar, will reduce it one third with water, and pass it through this machine, they will grind out first rate vinegar in one or two days' time. Sour beer or ale, the artificial cider, also, if it gets sour, make good vinegar when mixed with some other vinegar in making. Small beer, also drippings from sugar hogsheads in place of molasses, &c. Nothing having sugar or alcohol in it should be thrown away, as all will make good vinegar, which is as good as ca?h, and ought to be saved— if for no other purpose than to have the more to give the worthy poor.
J* 'vaa at first thought to be absolutely necessary to mafco the "inegar-fluid of about seventy-five degrees of heat, and also to keep the room of the same temperature ; but it has been found that by keeping the heat in the tub by the false top and the loose cover, that in warm weather it does very well without heating up the fluid, although it would make a little q^uicker with it ; and if desired to make in cold weather, you must heat the fluid and keep the room warm also.
If families choose to try this plan, they can make all they will need in a keg not larger than a common churn, whilst wholesalers will use tubs as tall as thair rooms will admit.
The first merchant to whom I sold this recipe, made all the vinegar he could retail by placing strips of board across the centre of a whisky barrel, which supported the shavings in the upper half only, allowing the vinegar to stand in the lower half ; as his room was so low, he could only use the one barrel and a wash tub at the top instead of the false-top and space as represented in our cut; it took him only a week to make i^in this way. I used the vinegar over a year. The strength of the fluid he used was good common whisky, one gal. ; water, four gals. So it will be seen that all kinds of spirit, or articles containing spirit, can be made into vinegar.
Remark — If you wish to make sugar into vinegar, do not attempt to run it through the generator, as it forms mother in that way, and soon fills up the little holes ; but make it by standing in a barrel, as mentioned under that head, No. 4.
8. Quick Process, by Standing upon Shavings. — Take 4 or 5 hogsheads or casks, and set them side by side, having a faucet near the bottom ; then fill up the casks full of shavings prepared as in the foregoing recipe, or clean corn-cobs, putting Bome turning shavings over the top, after having put on an old coffee sack to keep the fine shavings from falling down among the coarse on§s ; this is to keep in the warmth ; now sour the shavings with the best vinegar, by throwing it on the shavingf and letting it stand half a day or so; then draw ofl" by the faucet at the bottom, and throw it on again, adding 1 qt. of highwines to each ban el each time you draw it ofl", as the shavings absorb the acid, and t'^e vinegar would become flat, but by adding the'spirit the shavings become soured or acetified, and the vinegar gets better also. When the shavings are right, take highwines 30 or 40 per cent above proof 1 gal. ; molasses 1 qt. ; •oft water 14 gals. ; (river or well water will do, but not u goo*
sour to baiTel up.
Mr. Jackson, a Grocer, of Jackson, Michigan, has boon making in this waj for several years. He uses also, Mour ale, rinsings of sugar hogsheads, or the drippings, and throws this fluid on the shavings, and draws off and returns from one to three times each day until siiiBcieutly sour to barrel up, which only requires a few drawings ; he then fills his barrels only two-thirds full, and leaves the bungs out summer and winter, and if he finds a barrel is getting weak in Btrength, he puts in a quart of highwines, which recruits the strength, or gives it work again, which, as I remarked before, if you give him stock to work on, and air, he labor* — without both, he dies. Bear this in mind, and your vinegar will improve all the time, no matter how, or of what i* is made. He fills the tubs only one-third or one-half full when making, does not heat, but uses yeast, and only work* them in warm weather, and in winter fills the tubs with good vinegar, and lets them stand over until spting, whe» they are ready for work again.
three hundred barrels of vinegar in one season.
It might not be amiss, in closing this lovrj subject, to say that when you have no vinegar to begin with in either of the processes, that if you commence with the fluid quite weak at first, it begins to sour quicker than if begun with at full strength, then as it begins to become sour, add more of the spirit, cider, sugar, or molasses, &c., UBtil you get the desired point of strengih. So you might go on until a swallow of it would strangle a man to death, and remove every particle of skin from his throat.
BUTTER. — To Preserve any Length of Time. — First -work out all the buttermilk. Second — use rock salt. Tliird —pack in air-tight jars or cans. Fourth — keep in a cool place,
long. A short recipe, but it malces long butter.
Merchants, who take in more butter than they can sell during the warm months, can put it into jars and cover the jar with about half an inch of lard over the top of the but ter, and place it in the cellar ; or they can put about aw
inch or two of brine in place of the lard, and have it do well, first working out all the huttermilh which may remain, when bought in. It would be well for them to have their regular customei-s to furnish them butter, to whom they furuidh the right kind of salt, as the rock, or crystal salt, does not contain so much lime as the common, which u evaporated by artificial heat. Let sugar, and saltpeter, and dl other pe^fjAs, alone, if you wish good butter, either for proiscnt use or long keeping.
2. Making — Directions fok Dairymen. — If butter makers car dairymen, will use only shallow pans for their milk — and ?he larger the Gurface, and the less the depth of the milk the better — then put into each pan, before straining, 1 qt. of cold spring-water to every 3 qts. of milk, they will find the cream will begin to rise immediately, aud skim eveiy 13 hours, the butter will be free from all strong taste arising from leaves, or coarse pasturage.
It is a fact, also, that high or up-land makes better butter than when the cows are kept on rich bottom pasturage. The object of the cold water is double : it cools the milk, so that the cream rises before the milk sours, (for when milk becomes sour it furnisl^es no more cream,) and also improves the flav^or.
3. Storing — The (Illinois) Prairie Parmer's Method. — First, work the buttermilk carefully from the butter ; then pack it closely in jars, laying a thin cloth on top of the butter, then a thin layer of salt upon the cloth ; now have a dry cellar, or make it so by draining, and dig a hole in the bottom of it for each jar, packing the dirt closely and tightly around the jar, alhjwing the tops of the jars to stand only an inch or so above the top of the cellar bottom ; now place a board with a weight ujjon each jar to prevent removing by accident, and all is safe.
Merchants who are buying in butter, should keep each different lot separate, by using the thin cloth and salt, then another cloth over the salt before putting in the next lot, for mixed butter will soon spoil, besides not selling as well, acd finally cover the top as before described. If kegs or barrels are used, the outside must be as well painted as possible to prevent outside tastes, and also to preserve the wood.
FRUITS TO KEEP.— Without Loss op Color or Flavor — To each pound of rosin, put in 1 oz. of tallow, and 1 oz. of beeswax. Melt them slowly over the fire in an iron kettle, and be careM and not let it boil. T>U^ Uie JiiruU separately and rub
It over Trith whiting or fine chalk (to prevent the coating from adhering to the fruit,) then dip it into the sohition once and hold it up a moment to Bet the coating ; then pack away carefully in baiTcls or boxes in a cool place. When you dip oranges or lemons, loop a thread around to hold them; for pears or apples, insert a pointed stick to hold them by, then cut it off with a pair of sharp, heavy shears. Oranges or lemons cannot be put in boxes but must be placed on shelves, as the accumulated weight would mash them down.
It is now a well established fact that articles put up scientifically air-tight, may be kept fresh and fair for any length of time, or until wanted for use. This composition makes good sealing for air-tight cans or bottles, pouring it around the top of the can cover, and dipping the neck of the bottle into it. A patent has been secured for a compo sition for preserving fruit, of different proportions, however, from the foregoing, but the agent, at the Ohio State Fair in 1859, had such poor success in selling rights at three dollars that he reduced the price to twenty-five cents, and still but few would take hold of it, so that I think not much more will be done with the patent. I purchased twenty recipes for one dollar, but finding his composition to stick togetJier and tear off pieces wherever they touched each other, I went to work to improve it, as above. The patented proportions are, rosin 5 lbs., lard or tallow 8 oz., beeswax 4 oz. The patentee is John K. Jenkins, of Wyoming, Pa., and the patent was issued December 8, 1858. It does not work well on peaches or other juicy garden fruits.
EGGS. — To Preserve for Winter Use. — For every three gallons of water, put in 1 pt. of ficsh slacked lime, and common salt 1-2 pt. ; mix well, and let the barrel be about half full of this fluid, then with a dish let down your fresh eggs into it, tipping the dish after it fills with water, so they roll out without cracking the shell, for if the shell is cracked the egg ffH] spoil.
If fresh eggs are put in, fresh eggs will come out, as 1 have seen men who have kept them two, and even four, years, at sea. A piece of board may be laid across the top of the eggs, and a little lime and salt kept upon it, which keeps the fluid as strong at the top as at the bottom. This will not fail you. They must always be kept covered with the brine. I*'am'.li«« in towns and cities by this plan can hav3 eggs for winter ase at symmer prices. I have put up foLtv dozen , with entire success
The plan of preserving eggs has undoubtedly come from a patent secured by a geutleuian in England in 1791, Jaynes, of Sheffield, Yorshlre, ■which reads as follows:
2. English Patented Method. — " Put into a tub 1 bn. "Winchester measure, of quick lime, (which is fresh slaclied lime,) salt 32 oz. ; cream of tartar 8 oz. Use as much water as will give that consistency to the composition as will cause an egg to swim with its top just above the liquid. Then put and keep the eggs therein, which will preserve them perfectly sound at least 2 years."
Persons who think it more safe can follow this English plan. I desire in all cases to give all the information I have on each subject. Consequently I give you the follovfing also :
3. J. "W. Cooper, M. D.'s, Method op Keeping and ShtpfiNG Game Eggs. — " Dissolve some gum shellac in a sufficient quantity of alcohol to make a thin varnish, give each egg a coat, and after they become thoroughly diy, pack them in bran or saw dust, with their points downwards, in such a manner that they cannot shiit about. After you have kept them as long as you desire, wash the varnish carefully off, and they will be iii the same state as they were before packing, ready for eating or hatching."
This would seem to be from good authority, as Dr. Cooper has been engaged for the last thirty years in raising nothing but the best game fowls, and he has frequently imported eggs. He invariably directed them to be packed as above, and always had good success with them, notwithstaading the time and distance of the journey. He has also published a work upon Game Fowls. His address is Media, Delaware Co., Pa.
This last plan would be a little more troublesome, but still T"Quld not be very much to prepare all that families woulf* wish to use through the winter, or even for the retai V / ; as the convenience of having them in a condition to ship would be one inducement to use the last method, for tyith the first they must be taken out and packed in oats or flomething of that sort, to ship ; with the last they are always ready ; and weather permitting, about Christmas or New Year's, fresh and good eggs in cities always command Bufficient price to pay for all trouble and expense in th« •oreservation and shipment.
The Sex of Eggs. — Mr. Genin lately addressed tli« Academy des Sciences, France, on the subject of the sex of eggs. He affirms that he is now able, after having studied the subject for upwards of three years, to state with assurance that the eggs containing the germ of males, have wrinkles on their smaller ends, while female eggs are smooth at the extremities.
long to other departments :
4. To Increase the Laying. — " For several years past I have spent a few weeks of the latter part of August on the Kennebec river, in Maine. The lady with whom I have stopped is a highly accomplished and intelligent housewife. She supports a "h'^nncry " and from her I derived my information in the matter. She told me that for many years she had been in the habit of administering to her hens, with theii common food :
alternate day to 1 doz. fowls.
" Last season, when I was with her, each morning she brought in from twelve to fourteen eggs, having but sixteen hens in all. She again and again experimented in the uiait«r by omitting to feed with the Cayenne for two or three days. The consequence invariably was that the product of eggs fell off five or six per day. The same effect of u.sing the Cayenne is produced in winter as in summer." — Bustrm Transcnpt.
milk 1 cup.
Beat the eggs and flour together, then stir in the milk. Have a skillet with a proper amount of butter in it, made hot, for frying this mixture ; then pour it in, and when one side is done brown, turn it over, cooking rather slowly ; if a larger quantity is needed, it will require a little salt stirred in but for this amount, the salt in the butter in which yon fry it, seasons it very nicely.
ttrlskly, and it will at once become clear, when without the taking it would take from 6 to 7 qts. of alcohol to cut the cam,)hene, while with the least it is the best.
These proportions make the best burning fluid wtich can be combined. Many put in camphor gum, altlm, &c., the first to improve its burning qualities, the last to prevent explosion, but they are perfectly useless for either, from the tact that carapnor adds to the smoking properties, and nothing can prevent the gas arising from any fluid that wil] burn, from explosion, if the fire gets to it when it is eonSned. The only safety is in filling lamps in day-time, or far from fire or lights j and also to have lamps which are perfect in their construction, so that no gas may leak out »long the tube, or at the top of the lamp ; then let who will %y he can sell you a recipe for non-explosive gas or fluid, you may set him down at once for a humbug, ignoramus, or knave. Yet you may set fire to this fluid, and if not confined it will not explode, but will continue to burn until all is consumed. Families cannot make fluid any cheaper than to buy it, as the profit charged on the alcohol is usually more than tkat charged on fluid ; but they will have a better article by this recipe than they can buy, unless it is made from the same, and it is best for any one, even the retailer, only to make small quantities at a time, and get the freshest camphenc possible. When made in large quantities, even a barrel, unless sold out very soon, the last part 18 not as good as the first, owing to the separation of the camphene from the alcohol, unless frequently shaken, whilst being retailed out.
INTEREST.— Computing by One Multiplicaton and Onb i)rvisiON, AT ANY Kate Per Cent.— Multiply the amount by ihe number of days, (counting 30 days to each mouth.) Divided by 60 gives the interest at 6 per cent. do 45 " " 8 "
ExAMPi^E.— f 150 at 3 months and 10 days, or 100 days, is loOOO, divided by 60 gives $2,50 which is the interest at 6 per cent ; or divided by 45 gives $3,33 intei-est at 8 per cent, «fec.
the interest on any giren sum of money for any number of yearsj mouths or clays. Keduce the yeai"3 to months, add in the months if any, take one-third of the days and set to the right of th« months, in decimal form, multiply this reeult by one-half th< principal, and you have the interest ieqi'.ired.
The above example ia at six per cent. Rule to obtain th« interest at any other rate : For seven per cent increase the interest at six per cent by one-sixth, for eight per cent by one-third, for nine per cent by one-half, for ten per cent by two-thirds, for eleven per cent by five-sixths, for twelve per cent multiply by two. Twelve per cent is the highest rate of interest allowed by any State, except Minnesota, which, I believe, allows fifteen per cent.
In pointing off, persons will observe to point off as many figures in the product or answer as there are decimal points in the multiplicand. The balance, or remainder, sLow you tlie dollars and cents.
COUNTERFEIT MONEY.— Seven Rules for DeTECTiNG. — First — Examine the form and features of all human figures on the notes. If the forms are graceful and features distinct, examine the drapery — see if the folds lie natural ; and the hair of the head should be observed, and Bee if the fine strands can be seen.
Second. — Examine the lettering, tbe title of the bank, or the round handwriting on the face of the note. On all genuine bills, the work is done with great skill and perfectness, and there has never been a counterfeit but was defective in the lettering.
Third. — The imprint, or engraver's name. By observing the great perfection of the different company namesin the evenness and shape of the fine letters, counterfeiters never get the imprint perfect. This rule alone, if strictly observed, ^dli detect every counterfeit note in existence.
FeURTH. — The shading in the back-ground of th« vigfcette, or over or around the letters forming the name of the bank, on a good bill is even and perfect, on a counterfeit is irregular and imperfect.
Fifth. — Examine well the figures on the other parts of the note, containing the denomination, also the letters. Examine well the die work around the figures which stand for the denomination, to see if it is of the same character as that which forms the ornamental work surrounding it.
Sixth. — ^Never take a bill that is deficient in any of the •bove points, and if your impression is bad when you first •ee it, you had better be careful how you become convinced to change your mind — whether your opinion is not alt«red as you become confused in looking into the texture of the workmanship of the bill.
Seventh. — Examine the name of the State, name of the bank, and name of the town where it is located. If it has been altered from a broken bank, the defects can plainly be seen, as the alteration will show that it has been stamped oa.
INKS— Black Copying, or Wkiting Fluid. — Rain wat« 3 gals. ; gum arable i lb. ; brown sugar i lb. ; clean coperas i lb. ; powctered nutgalls i lb. ; bruise all, and mix, shaking occasion ally for 10 days, and strain ; if needed sooner, let it steep in an Iron kettle until the strength is obtained.
This ink can be depended upon for deeds or records which you may wish some one to read hundreds of years to come. Oxalic acid one-fourth oz. was formerly put in, but since the use of steel pens it does not work well on them. If not used as a copying ink, one-fourth the gum or sugar is sufficient as it flows more free without them.
2. Common Black. — Logwood chips 1 lb. ; boiJ in H gals, of water until reduced Lo 2 qts. ; pour off, and repeat the boilu:g i^in as before ; mix the two waters, 1 gal. in all ; then add Iw-chromate of potash { oz. ; prussiate of potash i ge. ; prussitte of iron (prussian blue) I oz. ; boil again about 5 minutes, atid itrain and bottle for use.
YovL will find none of the guminess about this ink that IS found iu that made from the extract of logwood ; yet it 18 not presumed that this will be as durable as the gall inks, for deeds, records, &c., &o., but for schools and common usft
pared with it, which was made two years ago.
3. Red — The Very Best.— Take an ounce vial and put into it a tea-spoon of aqua ammonia, gum arabic the size of 2 peas, and 6 grs. No. 40 carmine, and 5 grs. No. 6 or 8 caiinine also; fill up with soft water and it is soon ready for use.
This forms a beautiful ruling ink. I sold thg book in the Pike County Bank, 111., from the fact that this ink was BO much better than what they could get of any other make. Speaking of banks, makes me think of what a gentleman of Michigan City, Ind., told me about a black ink for banking purposes which would never fade, composed of twa articles only :
thrown to the public.
4. Blue. — Take sulphate of indigo and put it into water until you get the desired depth of color ; that sold in [little boxes foi blueing clothes is the article desired.
This does well for school children, or any writing not of importance to keep ; but for book keeping it is not good, as the heat of a safe in a burning building fades away the color.
5. Indelliblk. — Nitrate of silver 11 grs. ; dissolve it in 30 grs., (or about a tea-spoon) of water of ammonia; in 85 grs. (or 2i tea-spoons) ot rain water, dissolve 20 grs. of gum arabic. When the gum is dissolved put into the same vial also 22 grs. of carbonate of seda, (sal-soda.) When all is well dissolved, mix both vials, or their contents, and place the vial containing the mixture in a basin of water, and boil for several minutes, or until a black compotmd is the result. Wheji cold it is ready for use. Ilave the linen or other goods starched and ironed, and })erfectly dry ; then write with a quill pen.
If twice the amount is made at a time it will not cost any more, as the expense is only from the trouble of weighing, so little is used of the materials. Soft soap and boilinjj cannot eflface it. nor years of wear. Use only glass vessels, i
6. Powder— Black. — Sulphate of copper 1 dr. ; gum arable i oz. ; ci>pperas 1 ox. ; nutgalls and extract of logwood 4 ozs. ov:h ; all to be pulverized and evenly mixed. — Scientific American.
About one oz. of the mixture will be required to each ^-int of boiling water used. It will be found a valuable color for boot, shoe and harness-edge, also. It should stand a couple of weeks before using, or it may be steeped a few hours if needed sooner.
HONEYS. — Artificial Cuba Boswr —Good brown sugar 10 lbs. ; water 1 qt. ; old bee brea'' honey in the comb 2 lbs.; cream of tartar 1 tea-spoon ; gum arable 1 oz. ; oil of peppermint 3 drops; oil of rose 2 drops. Mix and boil 2 or 3 minutes and have ready 1 qt. more of water in which an egg is put well beat up ; pour it in, and as it begins t© boil, skim well, remove from the fire, and when a little cool, add 2 lbs. of nice bees' honey, and strain.
This is really a nice article, looking and tasting like honey. It has been shipped in large quantities under the name of " Cuba Honey." It will keep any length of time as nice and fresh as when first made, if sealed up. Some persons use a table-spoon of slippery elm bark in tliis amount, but it will ferment in warm weather, and rise to the 'op, requiring to be skimmed oflF. If it is to be used only iov eating purposes, the cream-of-tartar and gum arable may oe left out, also the old bee-bread honey, substituting for it mother pound of nice honey.
2. Domestic Honey. — Coffee sugar 10 lbs. ; water 8 lbs. ; cream of tartar 2 ozs. ; strong vinegar 2 table-spoons : the white of 1 egg well beaten ; bees' honey i lb. ; Lubin's extract of honeysuckle 10 drops.
First put the sugar and water into a suitable kettle and place upon the fire ; and when luke-warm stir in the cream of tartar, and vinegar; then continue to add the egg; and when the sugar is nearly melted put in the honey and stir until it comes to a boil, take it off, let it stand a few minutes, then strain, adding the extract of honeysuckle last, let stand over night, and it is ready for use. This resembles, candied honey, and is a nice thing.
4. Premium Honey. — Common sugar 4 lbs. ; water 1 pt. ; let them come to a boil, and skim ; then add pulverized alum J oz. ; remove from the fire and stir in cream of tartar ^ oz. ; and watci or extract of rose 1 table-spoon, and it is fit for use.
This took the premium at an Ohio State Fair. We use the recipes for common sugar and the one using Lubin'a extract of honeysuckle, and desire nothing better.
JELLIES — Without Fruit. — Take water 1 pt. and add to it pulverized alum i oz., and boil a minute or two ; then add 4 lbs. of white crushed or coffee sugar, continue the boiling a little, strain while hot; and when cold put in half of a two shilling bottle of extract of vanilla, strawberry, or lemon, or any other flavor you desire for jelly.
This will make a jelly so much resembling that made from the juice of the fruit that any one will be astonished alid when fruit cannot be got, it will take its place admirably. I have had neighbors eat of it and be perfectly aston» ished at its beauty and palatableness.
BAKING POWDERS— Without Drugs.— Baking soda 6 ozs. ; cream of tartar 8 oz. ; first dry them from all dampness by putting them on a paper and placing them in the oven for a short time, then mix and keep dry, in bottles or boxes.
The proper amount of this will be about one tea-spoon to each quart of flour being baked. Mix with cold water, and bake immediateli/. This contains none of the drugs generally used for baking powders ; it is easy made, and does not cost over half as much as to buy them already made. This makes biscuit very nice without milk or shortening. Yet if milk is used, of course it would be that much richer. The main object of baking powders is for those who are " Keeping bach, " as it is called, or for those who are far from civilized conveniencies, and for those who prefer this kind of bread or biscuit to that raised with yeast or sour milk and saleratus. I stand among the latter class.
then add the sugar ; if desired to have a very nice article, use gelatine in place of the. glue, and treat in the same manner ; when the sugar is dissolved in the glue pour it into moulds or a pan and cut it into squares, for convenience, before it gets too hard. This dissolves very quickly by placing the edge of a piece in the mouth, and is not unpleasant to the taste, ani is very handy for office or house use. Use to stick together torn bills, paper, &c., by softening the edge of a piece, as above, then touching the parts therewith and pressing together for a moment only.
Remarks. — If saloon keepers, and grocers, who deal in wine, beer, cider, &c., will follow our directions here, and Diake some of the following articles, they, and their customers, will be better pleased than by purchasing the spurious articles of the day ; and families will find thcra equally applicable to their own use. And although we start with an artificial cider, yet it is as healthy, and is more properly a small beer, which it should be called, but from its close resemblance to cider, in taste, it has been so named.
CIDERS. — Artificial, or Cider without Apples.— To cold water 1 gal., put dark brown sugar 1 lb. ; tartaric acid i oz. ; yeast 3 table-spoons, and keep these proportions for any amount desired to make ; shake it well together. Make it in the evening and it will be fit for use the next day.
I make in a keg a few gallons at a time, leaving a few quarts to make into next time — not using yeast again until the keg needs rinsing. If it gets a little sour make more into it. In hot weather draw in a pitcher with ice ; or if your sales are slow, bottle it and keep in a cool cellar according to the next recipe.
follows :
Put into a barrel, hot water 5 gals. ; brown sugar 30 lbs. ; tartaric acid t lb. ; cold water 25 gals. ; hop or brewers' yeast 8 pts. ; work the yeast into a paste with flour i lb. ; shake or atir
all well together; fill the ba.rel full, and let it work 24 to 4« hours, or until the yeast is done working out at the bung, by having put in a little sweetened water occasionally to keep tba baiTel full.
When it has worked clear, bottle it, putting in two or three broken raisins to each bottle, and it will nearly equal champagne. Let the bottles lay^n a cool place on the sid» — (observe also this plan of laying the bottles upon the side, in putting away apple-cider or wine) — but if it is only for your own retail trade you can make as follows in the next recipe, and have it keep until a barrel is retailed. The first recipe will last only three or four days in hot weather, and about two weeks in winter.
3, In Barrels for Long Keeping. — If retailers wish to keep this cider with the least possible loss of time, or families for their own drink or for the harvest field, proceed as follows :
Place in a keg or barrel, cold water 20 gals. ; brown sugar 15 lbs., and tartaric acid i lb. only, not using any yeast, but if you have them, put in 2 or 3 lbs. dried sour apples, or boil them and pour in the expressed juice ; without the yeast it will keep, in a cool cellar, for several weeks, even in summer. The darker the sugar the more natural will be the color of the cider.
Dr. 0. B. Reed, of Belle River, Mich,, with whom I read medicine, drank of this cider freely, while sick with bilious fever, knowing its composition, and recommended it to his patients as soon as he got out amongst them again, as a drink that would allay thirst, with the least amount of fluid, of any thing with which he was acquainted. But some will prefer Prof. Hufeland's drink for Fever Patients, which see.
4. Apple Cider, to Keep Sweet, with but TriFLING Expense. — Two things are absolutely necessary to preserve cider in a palatable state for any considerable time ; that is, to clear it of pomace, and then to keep it in a cool place, and the cooler the place the better. And theo if kept air-tight, by bottling, it is also better, but farmers cannot tj\ke the time nor expense of bottling. Some persons leach it through charcoal, and others boil, or rather scald and skim, to get clear of the pomace. In the firs^ place, cider, that is designed to keep over winter, should bo
fhea when made :
Stand in open casks or barrels, and put into each barrel about i pt. each of hickory, (if you have them, if not other bard wood), tshes and fresh slaclced lime ; stir the ashes and lime first into I qt. of new milk ; then stir into the cider. It will cause all the oomace to rise to the surface, from which you can skim it as it nses, 01 you can let it remain about 10 hours, then draw off by a faucet near the bottom, through a strainer, to avoid the hardened pomace.
It is now ready for bottling, or barreling, ii* too much trouble to bottle. If you barrel it, it has been found essential to sulphur the barrel. The sulphuring is done by dipping cotton cloth into melted sulphur, and drying it; then cutting into strips about two by six inches. Put about three gallons of cider into the barrel j^fire one end of the jtrip of the sulphured cloth, and introduce it into the bunghole, and hold it by means of the bung, giving it air sufficient to let it burn, keeping the smoke in as it burns, when vou will push the bung in tight and shake the barrel until the sulphur-gas is absorbed into the cider ; then fill up the barrel with cider, and if not already in the cellar, place it there, and you have accomplished the two points first spoken of If the above plan is too much labor, get oil barrels, if possible, to keep your cider in, (as vinegar can scarcely be made in an oil barrel, )the oil coming out a little and forming an air-tight coat on the top of the cider in the barrel
5. Jtlake your cider late m the Fall, and when made, put " hito each barrel, immedii.tely, ground mustard i lb.; salt 3 oz.; pulverized chalk 2 oz. ; stir them up in a little of the cider, then pour into the barrel, and shake well.
Take mustard seed, unground, 1 lb. ; isinglass 1 oz. ; alum pul verized 1 oz. ; put all into the barrel, leave the bung out, and shake or stir once a day for four days, then take new milk 1 qt., and half a dozen eggs, beat well together, and put them into the cider and stir or shake again, as before, for 2 days; then let It settle until you see that it is clear, and diaw off by a faucet.
And if you wish to use in place of wine, in medicine, put it into bottles ; but if designed for family use you can barrel it, bunging it tight, and keep cool, of course, and you will have a very nice article, if the cider was not made too near a well, or running stream of water ; .jut it is found that if made too near these, the cider does not keep. Judge ye why !
In some parts of England, by using only ripe, sound apples, letting it work clear, racking off about twice, bottling, &c., &c., cider is kept from twenty to thirty years. When cider is drawn off and bottled, it should not be corked until the next day after filling the bottles, as many of them will burst. Then lay on the side.
ST RUPS.— To MjiKE THE Various Colors.— Powder cochineal 1 oz. ; soft water 1 pt. ; boil the cochineal in the wafer foi a few minutes, using a copper kettle; while boiling, add 30 gra. of powdered alum, and 1 dr. of cream of tartar ; when the coloring matter is all out of the cochineal, remove it from the fire, and when a little cool, strain, bottle ana set aside for use.
This gives a beautiful red, and is used in the strawberry syrups only. Colored rather deep in shade. Pine apple ia left without color. Wintergrecn is colored with tincture of camwood, (not deep.) Lemon and ginger with tincture of turmeric. (See Tinctures.) The two last named syrupa »re not colored high — a light shade "only.
• 2. Artificial, Various Flavors. — The ground-work of aU syrups ought to be the same, t. e.. Simple Syrup ; to make it, take 2^ lbs. of the best coffee sugar, which is found not to crystalize, and water 1 pt., or what is the same, 60 lbs. sugar, waler 8 gals.
Take orris root, bruised, any quantity, say i lb., and just h !nd4f»mely cover it with dilute alcohol, (76 per cent, alcohol, and water, equal quantities,) so that it cannot'be made any stronger 3i the root.
This is called the " Saturated Tincture ;" and use sufficieut of this tincture to give the desired or natural taste of the raspberry, from which it cannot be distinguished.
The saturated tincture of orris, as above, 2 ozs., acetic-ether, 2 drs. ; mix, and use sufficient to give the desired flavor — a very little only is required, in either case.
5. P[NE Apple flavor is made by using to suit the taste, of butyric-ether. If persons have any doubt of these facts simply, try them. Some think syrups even for fountains, charged with carbonic acid gas, that it is best to use about three-fourths oz. of tartaric acid to each gallon, but I prefer none unless the fountain is charged with the supercarbonate of soda, in which case it is necessary to use about three-fourths oz. of the acid to each pound of sugar. See Soda Syrups.
This, above plan, for making simple syrup, is the true vay of making all syrups ; but some people think they must ise more water, that the syrup may be cheaper. Others will object to using artificial flavors. Oh ! they say : *' I Duy the genuine article." Then, just allow me to say, don't Imy the syrups nor the extracts, for ninety-nine hundredths of them are not made from the fruit, but are artificial. Rather make your own, as given under the head of Jams and Extracts. For the more watery syrups, see *' Soda Syrups."
Simple syrup, as above, and nice golden syrup, equal quantities of each, and mix well ; then use a few drops of oils of winiergreen and sassafras to each bottle, as used.
in some towns, using very high flavor, and in others jaljsr cient to percieve it, merely. All will soon get a ph ,i of their own, and like it better than that of others. This mixture of golden syrup makes the sarsaparilla a bo. atiful dark color without other coloring.
7. Lemon Syrup, Common, — Was formerly made >y dissolving four pounds of crushed sugar in one quart of water, by boiling, and adding three ounces of tartaric ac d and flavoring with the oil of lemon ; but it is best made an follows :
quart.
Rub the acid and oil in three or four spoons of the syrup_ then add the mixture to the remainder, and dissolve with gentle heat. Citric acid is not as likely to cause inflammation of the stomach as the tailaric, hence, its better adaptation to syrups calculated for drinks, and especially in disuise.
9. Lemon Sykup — To Save the Loss of Lemons. — Where you have lemons that are spoiling or drying up, take the insidea which are yet sound, squeeze out the juice, and to each pint put l^ lljs. white sugar, and a little of the peel ; boil a few minutes, strain and cork for use.
This will not require any acid, and one-half tea-spoon of soda to three-fourths of a glass of water with two or thiee table-spoons of syrup, makes a foaming glass. Some persons think they ought to put in water, but if water is added the syrup will not keep as well, and takes more of it.
10. Soda Syrup, With or Without Fountains. — The con*mon or more watery syrups are made by using loaf <jr crushert sugar 8 lbs. ; pure water 1 gal. ; gum arabic 2 oz. ; mix in h brass or copper kettle; boil until the gum is dissolved, then skim and strain through white flannel, after which add tananc acid 5J oz. ; dissolved in hot water ; to flavor, use extract <>{ lemon, orange, rose pine-apple, peach, sarsajmrilla, strawberry, &c„ i oz. to each bottle, or to your taste.
jipcr curbonato of soda, made fine ; stir well and be ready to iriuk, or use the soda iu water as mentioned in the " ImpeCJul Creaui Nectar ; " the gum arabic, however, holds the jdrbouic acid so it will not fly , off as rapidly as common ioda. The above is to be used ivithout fountains, that is to aaake it up as used, in glasses, or for the cheaper fountains which have an ounce of super-carbonate of soda to the gallon of water ; but for the fountains which are charged, in the cities, with carbonic acid gas, no acids are used in the lyrupa.
11. Cream Soda, Using Cow's Cream, for FotmTAXNS.-. Nice loaf sugar o lbs.; sweet rich cream 1 qt. ; water 1^ gills; warm jD:ra(lually so as not to burn ; extract of vanilla f ©z. ; exis^ci of nutmeg i oz.
Just bring to a boiling heat, for if you cook it any length of time it will crystalize ; use four or five spoons of this syrup instead of three as in other syrups. If used without a fountain, tartaric acid one-quarter pound is added. The tendency of this syrup is to sour rather quicker than other syrups, but it is very nice while it lasts ; and if only made in small quantities and kept cool, it more than pays for the trouble of making often.
12. Cream Soda, without a Fountain. — Coffee sugar 4 lbs ; water 3 pts. ; nutmegs grated 3 in number ; whites of 10 egga well beaten ; gum arable 1 oz. ; oil of lemon 20 drops ; or extract equal to that amount. By using oils of other fruits you can make as many flavors fi'om this as you desire, or prefer.
Mix all and place over a gentle firo,,and stir well about thirty minutes ; remove from the fire, strain, and divide into two parts ; into one-half put supercarbonate of soda eight ounces ; and into the other half put six ounces tartaric acid ; shake well, and when cold they are ready to use, by pouring three or four spoons, from both parts, into separate glasses which are one-third tnll of cool water ] stir each and potir together, and you have as nice a glass of cream soda as wafc ever drank, which can also be drank at your leisure, as the ^Tim and eggs hold the gas.
13. Soda Water, Without a JVIachtne for Bottling. — In each gallon of water to be used, carefully dissolve ^ lb. of erupheu sugar, and 1 oz. of super-carbonate of soda ; then fill t>«lf-pint botUes with this w»l.er, have your corks ready , now
mediately cork and tie down.
These bottles must be handled carefully without shaking, and keep cool, until needed; a little more or less sugar can be used to suit the taste of different persons.
OYSTER SOUP.— To each dozen or dish of oysters put J^ pt. water ; milk 1 gill ; butter J^ oz. ; powdered crackers to thicken. Bring the oj^sters and water to a boil, then add the other ingredients previously mixed together, and boil from 3 to 5 minutes only.
Each one will choose to add salt, pepper, &c., to their own taste. Keep about these proportions if you should have to cook for an oyster supper, for parties, «fcc.
TRIPE^To Prepare and Pickle. — First sew it up, after it is turned inside out ; be careful to sew it up tight, that no lime gets into it ; now have a tub of lime-water, the consistence of good thick white-wash ; let it remain in from 10 to 20 minutes, or until when you take hold of it, the dark outside skin will come oflf; then put it into clean water, changing three or four times to weaken the lime, that tiie hands be not injured by it ; then with a dull knife scrape olT all of the dark surface, and continue to soak and scrape several times which removes all offensive substances and smelL After this, let it soak 20 or 30 minutes in 2 or 3 hot waters, scraping over each time ; then pickle in salt and water 12 hours, and it is ready for cooking ; boil from 3 to 4 hours, cut in strips to suit, and put it into nice vinegar with the various spices, as desired ; renew the vinegar at the expiration of 1 week, is all that will be required further.
MOLASSES CANDY KWD POP-CORN BALLS— Candy. — Equal quantities of brown sugar and molasses, and put them into a suitable kettle — copper is the best — and when it begins to boil, skim it well, and strain it, or else pour it through a fine wire sieve to free it of slivers and sticks which are often found in the sugar ; then return it to the kettle and continue to boil, until, when you have dipped your hand in cold water and passed one or two fingers through the boiling candy and immediately back to the cold water, w'hat adheres, when cold, will crush like dry egg shells, and does not adhere to the teeth when bitten. When done, pour it on a stone or platter which has been greased, and as it gets cool begin to throw up the edges and work it by pulling on a hook or by the hand, until bright and glistening like gold ; the hands should have a little flour on them occasiou*
»I1t; now keep the mass by a warm stove, (if much is made at oue time), and draw it into stick size, occasionally rolling Iheni to keep round, until all is pulled out and cold, then with shears clip a little upon them, at proper lengths for the sticks, ind they will snap quickly while yet the stick will bend ; nc px)lor no butter, no lard or llavor is used or need be, yet any oil can be used for flavoring, if desu'ed, when poured out to cool.
Sugar left in molasses barrels works very nicely in thia preparation. Pulverized white sugar sprinkled amongst it will prevent it from sticking together.
candy that is perfectly white, proceed as follows :
Best cofifee sugar 2^ lbs. ; the nicest syrup li pts. ; boi! very carefully, until when tried as above, it crisps like egt^ shells, or flies like glass ; then draw and work upon the hook imtil very white.
3. Molasses Candy Without SaoAn. — Poilo-Rico molasses boiled and worked as above, has a cream shade according to the amount of pulling, and most jiersons prefer it to the mixture of sugar and molasses, as in the lirst.
4. Pop Corn Balls.— Pop the corn, avoiding all that is not aiccly opened; place i bu. of the corn upon a table or in a large dripping pan ; put a little water in a suitable kettle with sugar 1 lb. ; and boil as for candy, until it becomes quite waxy in water, when tried as for candy ; then remove from the fire and dip into it 6 to 7 table-spoons of thick gum solution, made by pouring boiling water upon gum arable, over night, or some houi-s before ; now dip the mixture upon different parts of the corn, putting a stick, or the hands, under the corn, lifting up and mixing until the corn is all saturated with candy mixture ; then with the hands press the corn into balls, as the boys do snow balls, being quick, lest it sets before you get through.
This amount will make about one hundred balls, if properly done. White or brown sugar may be used. And for variety, white sugar for a part, and molasses or syrup for another batch. Either of these are suited to street pedilara.
5. Action of sugar or Candy on the Teeth. — M Larez, ot France, in the course of his investigations on the teeth, has arrived at the following conclusions :
First — that " refined sugar, either from cane or beet, is injurious to healthy teeth, either by immediate contact with these orfans^ or by the gas developed, owing to ita stoppage in the
stomach. Second — that if a tooth is macerated in a sati'jatftd solution of sugar, it is so much altered in the chemical coniposi tion that it becomes gelatinous, and its enamel opaque, sponjjy, and easily broken. This modification is due not to free acid, but to a tendency of sugar to combine with the calcareous basis of the teeth."
I have destroyed my own teeth, I liave no doubt now, by eQnstautly eating candies, while in the grocery business, be fore I knew its injurious effects, and I believe it to have de stroyed the Jirst teeth of all of my children which werf bo.n during my candy-eating propensities. "What say our candy-eating gentry to the above 1 *
LEMONADE. — To Carry in the Pocket. — Loaf sugar 1 lb. ; rub it down finely in a mortar, and add citric acid i oz. ; (tartaric acid will do,) and lemon essence i oz., and continue the trituration until all is intimately mixed, and bottle for use. It is best to dry the powders as mentioned in the Persian SherDet, next following.
A rounding table-spoon can be done up in a paper and carried conveniently in the pocket when persons are going into out-of-the-way places, and added to half pint of cold water, when all the beauties of a lemonade will stand belbre you waiting to IJe drank, not costing a penny a glass. This can be made sweeter or more sour, if desired. If any howevei should prefer an effervescing drink, they can follow the directions given in the next recipe.
Persian Sherbet. — Pulverized sugar 1 lb. ; super-carbonate of soda 4 ozs. ; tartaric acid 3 ozs. ; put all the articles into the stove oven when moderately warm, being separate, upon papei or plates ; let them remain sufficiently long to dry out all dampness absorbed from the air, then rub about 40 drops of lemon oil, (or if preferred any other flavored oil,) thoroughly with the 6\igar in a mortar — wedge-wood is the best — then ad.d the soda and acid, and continue the rubbing until all are thoroughly mixed.
Bottle and cork tight, for, if any degree of moisture is ermitted to reach it, the acid and soda neutralize each ther, and the virtue is thus destroyed. A middling siacd table-spoon or two tea-spoons of this put into a half pint glass and nearly filled with water and quickly drank, makes an agreeable summer beverage ; and if three or four glasses of it are taken within a short time, say an hour or two, it has tht effect of a gentle cathartic, hence lor those habit
ually costive it vrould be found nearly or quite equal to the seidlite powder, and for children it would be the pleasantest of the two. [The printers have tried it, and can bear testimony to its good qualities.]
BEERS. — Root Beer.— For each gallon of water to be used, take hops, burdock, yellow dock, sarsaparilla, dandelion, and spikenard roots, bruised, of each i oz. ; boll about 20 minutes, and strain while hot, add 8 or 10 drops of oils of spruce and sassafras mixed in equal proportions , when cool enough not tc scald your hand, pat in 2 or 3 table-spoons of yeast ; molasses ^ of a pint, or while sugar i lb. gives it about the right sweetness.
Keep these proportions for as many gallons as you wish to make. You can use more or less of the roots to suit your taste after trying it ; it is best to get the dr'- ""M>ib. or dig them and let them get dry, and of course you can add any other root known to possess medicinal properties desired in the beer. After all is mixed, let it stand in a jar with a cloth thrown over it, to work about two hours, then bottle and set in a cool place. This is a nice way to take alteratives, without taking medicine. And families ought to make it every Spring, and drink freely of it for several weeks, and thereby save, perhaps, several dollars in doctors' bills,
2. Spruce or Aromatic Beer. — For 3 gals, water put in 1 qt. and ^ pt. of molasses, 3 eggs well beaten, yeast 1 gill. Into 3 qts. of the water boiling hot put 50 drops of any oil yon nish the flavor of; or mix 1 oz. each, oils sassafras, spruce and wiutergreen, then use 50 drops of the mixed oils.
Mix all, and strain ; let it stand two hours, then bottle, oearing in mind that yeast must not be put in when the fluid would scald the hand. Boiling water cuts oil for beers, equal to alcohol
3. Lemon Beer. — Water 30 gals. ; ginger root bruised 6 ozs. ; cream of tartar i lb. ; coffee sugar 13 lbs. ; oil of lemon 1 oz. ; or i oz. of the oil may be used, and 6 good sized lemons, sliced : yeast 1^ pts.
Boil the ginger and cream of tartar, about twenty to thirty minutes, in two or three gallons of the water; then strain it upon the sugar and oils or sliced lemons, which have been rubbed together, having warm water enough to make the whole thirty gallons just so you can hold your hand in it *it)iout burning, or about seventy degrees of heatj then
work up the yeast into a paste, as for the eider, with five or six ounces of flour. Let it work over night, skimming off the yeast, or letting it work over as the cider, then strain and bottle for use. This will kesp fifteen or twenty days. The Port Huronites think it a splendid drink.
Boil the ginger thirty minutes in three qts. of the water ; then add the other ingredients, and strain ; when cold, put in the white of an egg, well beaten, with one tea-spoon of lemon essence — let stand four days, and bottle. It will keep for months — much longer than if yeast was used ; the honey, however, operates mildly in place of yeast.
6. i'HitADKi.PQiA Beer. — Water 3t> gals. ; brown sugar 20 lbs. ; ginger, bruised, IJ lbs. ; cream of tartar i lb. ; super carbonate of soda 3 ozs. ; oil oi lemon, cut iu a little alcohol, 1 tea-spoon whites of 10 eggs, well beuleu ; hops 2 ozs. ; yeast 1 qt
The ginger root and hops should be boiled twenty oi thirty minutes in enough of the water to make all milk warm, then strained into the rest, and the yeast added and llowcd to work over night; skimmed and bottled.
6. Patent Gas Beer. — Ginger 2 ozs. ; allspice 1 oz. ; cinnamon i oz. ; cloves i oz. ; all bruised or ground ; molasses 2 qts. , cold water H gals. ; yeast 1 pt.
Boil the pulverized articles, for fifteen or twenty minutes, in the molasses; then strain into your keg, and add the water, then the yeast ; shake it well together and bung down. If made over night it will be ready for use the next day. This beer is ahead of all the pops and mineral waters of the day, for flavor, health or sparkling qualities or speed in making. Be careful you do not burst the keg. In hot weather, draw in a pitcher with ice. I have sold this in the principal towns of Ohio, Indiana and Michigan, traveling with a caravan, and obtained two dollars for the recipe of the man who kept the inside stand, and blowod the head out of the first keg of it which he made,
7. Corn Beer, Without Yeast.— Cold water 5 gals. ; eouod nice com 1 qt. ; molasses 2 qts. ; put all into a keg of this slise; shake well, and hi 2 or 3 days a fermentation will have been brought on as nicely as with yeast. Keep it bunged tight
It may be flavored with oils of sprtice or lemon, if desirhA, bf pouring on to the oils one or two quarts of the water, boiling hot. The corn will last five or six makings. If it gets too ss'^ur .idd more molasses and water in the same pro portions. It is obeap, healthy, and no bother with yeast.
8. Strc-'^'g Bi!.ER, English Impro\^d. — Malt 1 peck; conrse brown suj,. ' 6 lbs. ; bops 4 oz. ; good yeast 1 lea-cup ; if you have not nit. '^ take a little over 1 peck of barley, (twice the amount o' oats s-ill do, but are not as ^od,) and put it into an oven after the bread is drawn, or into a stove oven, and steam the moisture from them. Grind coarsely.
Now pom' ujx)n the ground malt 8^ gals, of water at 170 or 172 ® ot heat. The tub in which you scald the malt should have a false bottom, 2 or 3 inches from the real bottom ; the false bottom should ^e bored full of gimlet holes, so as to act as a steamer, to keep i^ck the malt meal. When the water is poured on, stir them well, and let it stand 3 hours, and draw ofl by a faucet ; put in 7 gals, more of water at 180 to 182 ° ; stir it well, and let it stand 2 hom-g and draw it off Thee put on a gal. or two of cold water, stiriowell and draw it ofl ; you should have about 5 or 6 gals. Put the 6 lbs. of coarse brown su^ar in an efjual amount of water; mix with the wort, and bod li to 2 hours with the hops ; you should have eight gals, when boiled ; when cooled to 80 <^ put in the yeast, and let it work 18 to 20 hours, covered with a sack; use sound iron hooped kegs or porter bottles, bung or cork tight, and in two weeks it will be good sound beer, and will keep a long time ; and for persons of a weak habit of body, and especially females, 1 glass of this with tlieir meals is far better than tea or coffee, or all the ardent spirits in the universe. If more malt is used, not exceeding i a bushel, the beer, of course, would have more spirit, but this strength is sufficient for the use of families or invalids.
9. Ale, Home-Brewed — How it is Made. — The follow, mg formula for the manufacture of a famous home-brewed ale of the English yeomanry, will convey a very clear idea of the components and mixture of ordinary ales. The middle classes of the English people usually make their ale in q -lantities of two barrels, that is, seventy-two gallons.
For this purpose a quarter of malt, (8 bus.) is obtained at the iwalt-house — or, if wished to be extra strong, nine bushels of milt — are taken, with hops, 12 lbs. ; yeast, 5 qts.
The malt, being crushed or ground, is mixed with 72 gals, of water at the temperature of IGOP , and covered up for 3 hours, when 40 gallons ai'e drawn olf, into which the hops are put, and left to infuse. Sixty gallons of water at a temperature of 170® are then added to the malt in the mash- tub, and weii
mixed, and after stauding S liours, sixty gallons are drsxwn off The wort from these two mashes is boiled with the hops for 3 hours, and after being cooled down to 65 ° , is strained through a flannel bag into a fermenting tub, where it is mixed with the yeast and left to work for 24 or 30 hours. It is then run into barrels to cleanse, a few gallons being reserved for filling up the casks as the yeast works over.
Of course when the yeast is worked out it must be bunged It* one-half a pint of ihis was taken each meal by men, and hail that amount by females, and no other spirits, tea noi coffee, during the day, I hesitate not in saying that I firmly believe it would conduce to health. I know that this, which a man makes himself, or some of the wines mentioned in this work, home-made, are all that any person ought to allow themselves to use in these days when dollars and cents are the governing influences of all who deal in such articles.
10. Porter, Alb, or Wine, to Prevent Flatness in Parts of Bottles for the Invalid. — Sick persons who are recommended to use ale, porter, or wine, and can only take a small glass at a time, nearly always find the last of the bottle flat or stale.
This plan prevents communication with the external air.
11. Cream Nectar, Imperial. — First, take water 1 gal. ; loaf sugar 8 lbs., tartaric acVi 8 oz. ; gum arable 1 oz. ; put into a suitable kettle and place on the fire.
Second, take flour 4 tea-spoons; the whites of4 eggs, well beaten together, with the flcur, and add water i pt. ; when the 8rst is blood warm put in the second, and boil 3 minutes, and it is done.
Directions : Three table-spoons of the syrup to a glasa half or two-thirds full of water, and add one-third tea-spoon i)f super- carbonate of soda, made fine; stir well, and drink at your leisure.
B^"In getting .up any of the soda drinks which are spoken of, it will be found preferable to put about eight ounces of super-carbonate, often called carbonate of eoda, into one pint of water in a bottle, and shake when you wish to make a glass of soda, and pour of this into the glsss until it foams well, instead of using the dry soda as directed.
18, GutoEft Pop.— Water 5i gals. ; ginger root, bruised, i lb. ; tartaric acid i oz. ; -white sugar 2i lbs. ; whites of 3 eggs, -well beaten ; lemon oil 1 tea-spoon ; yeast 1 gilL
Boil the root for thirty minutes in one gallon of the water, strain off, and put the oil in while hot ; mix. Make over night, and in tJie morning skim and bottle, keeping out dediments.
tartar, and 3 lemons sliced.
DiiiECTiONS: In making 5 gals, boil the ginger and lemons 10 minutes in 2 gals, of the water; the sugar and cream of tartar to be dissolved in the cold water, and mix all, and add i pint of good j^east ; let it ferment over night, strain and bottle in the mornmg.
This is a valuable recipe for a cooling and refreshing beverage ; compoiinded of ingredients highly calculated to aisjist the stomach, and is recommended to persons suffering with Dyspepsia or Sick Headache. It is much used in European countries, and persons having once tested its virtues will constantly use it as a common drink. And for saloons, or groceries, no temperance beverage will set it aside.
14. Siiam-Champagne — A Puuely Temperance DRmK. — Tartaric acid 1 oz. ; one good sized lemon ; ginger root 1 oz. ; white sugar 1^ lbs. ; water S4- gals. ; yeast 1 gill.
Slice the lemon, and bruise the ginger, mix all, except the yeast, boil the water and pour it upon them and let stand until cooled to blood heat ; then add the yeast and let it stand in the sun through the day ; at night, bottle, tieing the corks, and in 3 days it will be fit to use. — Mrs. BeecJier.
Boil the hops twenty minutes in the water, strain into a jar, and stir in the flour, sugar, and salt, and when a little cool add the yeast, and after four or five hours cover up, and stand in a cool place or on the ice for use.
Boil the hops for thirty minutes in the water, strain, and let cool until yoxi can well bear your hand m it; then stir in the flour aud yeast; keep in a warm place until the fermentation is well under way, and then let it work in a cooler plac8 six to eight hours, when it should be put in pint botr ties about half full, and closely corked, and tied down. By keeping this in a very cool cellar, or ice-house, it will keep for months, fit for use. But as it is often troublesome to obtain yeast, to start with, I give you the " Distillers' Jug Yeast," starting without yeast.
Boil the hops in the water until quite strong, strain, and Btir in the malt flour ; and strain again through a coarse cloth, and boil again for ten minutes; when lukewarm, stir in the sugar, and place in a jug, keeping it at the same temperature until it works over ; then cork tight, and keep in a cold place.
Boil the potatoes, after peeling, and rub them through a cullender; boil the hops in two quarts of water, and strain into the potatoes; then scald sufiicient Indian meal to make them the consistence of emptyings, and stir in the yeast and let rise ; then, with unscalded meal, thicken so as to roll out and cut into cakes, drying quickly, at first, to prevent souring. They keep better, and soak up quicker, than if made with flour.
, ICE CREAM.— Fresh cream i gal. ; rich milk i gal. ; white sugar 1 lb. ; some do use as much as 2 lbs. of sugar to the gallon, yet it leaves an unpleasant astringency in tbe throat after eating the cream, but please yourselves.
Dissolve the sugar in the mixture, flavor with extract to suit your taste, or take the peel from a fresh lemon and steep onemlf of it in as little water as you can, and add this — it Quakes the lemon flavor better than the extract — and no fl&vor will bo universally please as thp lemon ; keep the same proportion for any amount d.esired. The juice of strawberries or raspberriet gives a beautiful color aud flavor to ice creams ; or alniut i on
About half an hours' constant stirring and occasional B«raping down and beating together, will freeze it. The old-fashioned freezer which turns in a tub of ice, makes smoother and nicer ice-cream than all the patent freezers I have seen ; and the plan of using the genuine cream and milk gives sufficient profit ; but I will give you the best substitutes there are, in the following recipe, but the less you eat of either the better will it be for health.
starch i lb.
First dissolve the starch in one quart of the milk, then mix all together and just simmer a little, (not to boil.) Sweeten and flavor to suit your taste, as above ; or —
Fh'st soak the moss in a little cold water for an hour, and rinse well to clear it of sand and a certain peculiar taste ; then Bteep it for an hour in the milk just at the boiling point, but not to boil ; it imparts a rich color and flavor without eggs or cream. The moss may be steeped twice.
It is the Chicago plan. I have eaten it and know it to be very nice. A few minutes rubbing, at the end of freezing, with the spatula, against the side of the freezer, givea ice-cream a smoothness not otherwise obtained.
■WINE8. — Currant, Cherry, and other Berry "Wines. — The juice of either of the above fruits can be used alone, or in combinations to make a variety of flavors, or suit persons who have some, and not the other kinds of fruit.
Express all the juice you can, then take an equal amount of boiling water and pour on the pressed fruit, let stand 3 hours, Kjueeze out as much as there is of juice, and mix, then add 4 lbs. 01 brown sugar to each gallon of the mixture ; let stand until worked, or 3 or 4 weeks, without a bung in the kej, or barrel, simply putting a piece of gauze over the bung hole to keep out CJes ; when it is done working, bung it up.
A cool cellar, of cotirse, is the best place for keeping wines, as they must be kept where they will not freeze. Some persons use only one-fourth juice, in making fruit w'mea, and three-fourths water, but you will bear in mind
that the wine will be good or bad, just in proportion to tha water and sugar used. If care is used when you express the juice, to prevent the pulp or seeds from entering or remaining in the juice, uo other straining or racking will be needed. Most persons also recommend putting in brandy, but if any spirit is used at all, let it be pure alcohol, from one gill to one-half pint only per gallon, but the strength of juice I recommend, and the amount of sugar, remove all Necessity for any addition of spirit whatever. Bear inmlrd that all fruit of which you are to make wine ought to be perfectly ripe, and then make it as soon as possible thereafter, not letting the juice ferment before the addition of the sugar. If bottled, always lay them on the side.
of the garden rhubarb.
To each gal. of juice, add 1 gal. of soft water in wbich 7 lbs. of brown sugar has been dissolved ; fill a keg or a barrel with this proportion, leaving the bung out, and keep it filled with sweetened water as it works over until clear ; then bun^ down or bottle as you desire.
These stalks will furnish about three-fourths their weight in juice, or from sixteen hundred to two thousand gallons of wine to each acre of well cultivated plants. Fill the barrels and let them stand until spring, and bottle, as any wine will be better in glass or stone
3. ("^ome persons give Mr. Gaboon, of Kenosha, Wis., credit for originating pie-plant wine, but that is a mistake ; it has long been made in England, and has even been patented in that country. They first made it by the following directions, which also makes a very nice article, but more applicable for present use than for keeping.
For every 4 lbs. of the stalks cut fine, pour on 1 gal. of boiling water, adding 4 lbs. brown sugar ; let stand covered 24 hours, having also added a little cinnamon, allspice, cloves and nutmeg, bruised, as may be desired for flavoring ; then strain and let work a few days, and bottle.
begins — tWft ought to be done in making any fruit wine. Something of the character of a cheese press, hoop and cloth, is the best plan to squeeze out the juice of toniatoea or other fruits, hot the wine stand in a keg or ban'el for two or three months ; then draw off into bottles, carefuUj avoiding the sediment. It makes a most delightful wine having all the beauties of flavor belonging to the tomato, and I have no doubt all its medicinal properties also, either as a tonic in disease, or as a beverage for those who are in the habit of using intoxicating beverages, and if such persons would have the good sense to make some wine of this kind, and use it instead of rot-gut whisky, there would not be one-hundredth part of the "snakes in the boot " that now curse our land. It must be tasted to be appreciated. I have it now, which is three years old, worth more than much pretended wine which is sold for three or four shillings a pint.
5. Tomato Cultivation, for Early and Late. — The Working Farmer say-s of the tomato plant, " that it bears 80 per cent of its fruit witliin 18 inclies of thegrouud, while more than iialf the plant is above that pai't. Wlien the branches are cut tliey do not bleed, and they may tlierefore be shortened immediately above the large, or early-setting fruit.
" The removal of the small fruit on the ends of the branches is no loss, for the lower fruit will swell to an unnatural size by trimming, and both a greater weight and D\e;isuro of fruit will be the consequence, besides obtaining a large portion five to fifteen days earlier. The trimming should be done so as to have a few leaves beyond the I'ruit, to insure perfect ripening. The importance of early manuring is too evident to need comment. The burying of the removed leaves immediately around the plant is a good practice, both by insuring full disturbance of the soil, and by the presenting of a fertilizer progressed precisely to the point of fruit making. The portions buried decay rapidly, and are rapidly assimilated." If wanted very early and large, trim off all except two or three upon each plant.
6. To ripen late tomatoes, pull the plants having green tomatoes on them, before tlie commencement of frosts, and hang them in a well ventilated cellar.
7. The Tomoto as Food. — Dr. Bennett, a professor of some celebrity, considers the tomato an invaluable article of diet, and ascribes to it various important medical properties.
Mrst — that the tomato is one of the most powerf\il aperienta for the liver and other organs; -vviiere cal&niel is indicated, it is probably one of the most elTective and least harmful remedial agents known to tlie profession. Second — that a chemical extract will be obtained from it that will siqyercede the use of calomel in the cure of disease. Third — that he has successfully treated Diarrlicea with this article alone. Fourth — that when used as an article of diet, it is an almost sovereign remedy for Dyspepsia and indigestion. Fifth — that it should be constantly used for daily food, either cooked or raw, or in the form of catchup ; it is the most healthy article now in use.
Knowing personally the vakie of the tomato in disexse, for food and wine, I freely give all the information regarding it which I can, that others may make as free use of it as health and economy demand, consequently, I give you the next item, which I have learned just as the type were being set, upon this subject in 1860.
8. Tomatoes as Food for Cattle. — Mr Davis, the editor of the " Michigan State News/' Ann Arbor, Mich.. Bays, " that he has fed his cow, this season, at least ten bushels of tomatoes."
of rich and delicious milk.
He did not think of it until after the frosts, when ob serving them going to waste, he thought to see if she would eat them, which she did freely, from the commencement. I have also known pigs to eat them, but this is not common In 1862, I found my cow to eat them as freely as spoken of by Mr. Davis.
8. Wine, from White Currants. — Ripe, white currants, any quantity; squeeze out the juice, and put on water to gel out as much more as there is of the juice, .and mix the two, and to eacli gallon put 3i lbs. of sugar; let it work without boiling oi skimming for 2 or 3 months, then rack otf and bottle.
root, bruised, 1 oz. ; cayenne 5 grs. ; tartaric acid 1 dr. ; 'let stand 1 week and filter, or draw off by faucet above the sediment. Now add 1 gal. of water in which 1 lb. of crushed sugar haa been boiled. Mix when cold. To make the color, boil J oz. of cochineal, f oz. of cream of tartar, i oz. of saleratus, and i oz. of alum in 1 pt. of water until you get a bright red color, and use a proper amount of this to bring the wme to the desired color.
This wine is suitable for nearly all the purposes for whirh any wine is used, and a gallon of it will not cost more thao a pint of many wines sold throughout the country for medicinal purposes, represented to be imported from Europe. Let a man, suffering with a bad cold, drink about half a pint of this wine hot, on going to bed, soaking his feet at the same time in hot water fifteen or twenty minutes, and covering up warm and sweating it out until morning, then washing off his whole body with cool or cold water, by means of a wet towel, and rubbing briskly with a coarse dry towel for four or five minutes, will not be able to find hia cold or any bad effects of it in one case out of a hundred. Ladies or children would take less in proportion to age and strength. Females in a weakly condition, with little or no appetite, and spare in flesh, from food not properly digesting, but not yet ripened into actual indigestion^ will find iilmost entire relief by taking half a wine-glass of this wine twenty minutes before meals, and following it up a mouth or two, according to their improved condition. For family use it is just as good without color, as with it.
11. Blackberry Wine. — Mash the berries, and pour 1 qt. ot boiling water to each gal. ; let the mixture stand 24 hours, stirring occasionally ; then strain and measure into a keg, adding 3 lbs. of sugar, and good rye whisky 1 pt., or best alcohol i pt. to each gal.
Cork tight, and let it stand until the following October, and you will have wine fit for use, without further straining or boiling, that will make lips smack as thev never smacked under its influence before.
I feel assured that where this fruit is plenty, that this wine should take the place of all others, as it is invaluable in sickness as a tonic, and nothing is better for bowel disease. I therefore give the recipe for making it, and having tried it myself, I speak advisedly on the subject.
sour without it.
12. Laavton Blackberry — Its Cultivation.- An editor at Coldwater, Mich., says of this fruit, " that where it is best known it is one of the most popular small fruits tliat has ever been cultivated. It has been known to produce over one thousand full-grown ripe berries in one season on a single stalk ; the average size of fruit being from threefourths to one and a half inches in diameter; quality excellent, very juicy, seeds very small, and few in number. Five quarts of berries will make one gallon of juice, which, mix^d with two gallons of water and nine pounds of refined sugar, will make three gallons of wine, equal in quality to the best grape wine. Professor jMapes and many others, who have tested the qualities of the same as a wine-fruit, speak 3 1 it in terms of the highest praise.
Mash th ' grapes without breaking the seed ; tJien put them into i barrel with the sugar and alcohol, au<i fill up with rain water, and let it lie a few weeks in the sun; or if tlie weather hat become cold, in a warm place; then in the cellar until spring ; then rack off and bottle, or place in perfectly clean kegs or barrels, and you have a better article than nine-tenths of what is represented as imported Port.
14. Cider Wine. — Prof. Horsford, a celebrated cliemist, communicated the following recipe to the Horticultural Society of Massachusetts, and recoumiends it for general trial :
" Let the new cider from sonr apples, (ripe, sound fruit preferred,) ferment from 1 to 3 weeks, as the weather is warm or cool. "Wheu it has attained to a lively fermentalion, add totach gallon, according to its acidity, from | a lb. to 2 lbs. of w hite crushed sugar, and let the whole ferment until it possesses precisely the taste which it is desired should be permanent. In tliif condition pour out a quart of the cider and add for each gallon \ oz. of sulphite of lime, not sulphate. Stirthe powder and cider until intimately mixed, and return the emulsion to the fermenting liquid. Agitate briskly and thoroughly for a tew moments, and then let the cider settle. Fermentation will cease at onca-
When after a few days, tlie cider has become clear, draw off carefully, to avoid the sediment, and bottle. If loosely corked which is better, it will become a sparkling cider wine, and may oe kept indefinitely long.
This has been tried with varied success ; those who do flot think it too much to follow the directions, obtain a good article, but others, supposing it to do just as well without sugar, or drawing oflF, or bottling, have found but little satisfaction -they have no rea.son*to expect any ; and yet they might be well satisfied to obtain a good wine from the or ehard, even with all the above requisitions.
15. Ghape WmB. — " Ripe, freshly picked, and selected, tame grapes, 20 lbs. ; put them into a stone jar and pour over them 6 qts. of fx)iling soft water ; when sufiiciently cool to allow it, you will squeeze them thoroughly with the hand ; after which allow them to stand 3 days on the pomace with a cloth thrown over the jar, then squeeze out the juice and add 10 lbs. of nice crushed sugtu", and let it remain a week longer in the jar ; then take off the scum, strain and bottle, leaving a vent, until done fermenting, when strain again and bottle tight, and lay the bottles on the side in a cool place,"
This wine is the same as used by the Rev. Orrin Whitmore, of Saline, Mich., for sacramental purposes. I have lasted it myself, and would prefer it for medicinal uses to nine-tenths of the wines sold in this country. With age, it is nice. I am of the opinion that it might just as well remain in the jar until it is desired to bottle, and thus save the trouble of the extra straining. For I have now wine, four years old in my cellar, made in Evansville, Ind., from the grape, which was made without the addition of any particle of matter whatever. Simply, the juice pressed out, hauled in from the vinery, put into very large casks in a cool cellar, aot even racked off again under one year from the time of Qiaking, It tastes exactly like the grape itself; this, you will perceive, saves much trouble in racking, straining, &c [ am told by other wine makers also, that if care is observed ^hen the juice is pressed out to keep clear of the pomace, that wine is better' to stand without racking or straining, and that nothing is found in the barrels, after the first year, save the crude tartar or wine-stone, as some call it, which all grape wine deposites on the sides of the ca,sk. These wines are every way appropriate for sacramental and medieinaJ
purposes, and far more pure than can be purchased once in a hundred timea, and if one makes their own, they have the satisfaction of knoicing that their wines are not made of what ij Tulgarly, yet truly called, " Rot-gut whisky."
10. CoLOKiNG Fon Winks. — White sugar 1 lb. ; water 1 ^ill • put into an iron kettle, let boil, and burn to a red blaok, and thickremove from the fire and add a little hot water to keep it froin hardening as it cools ; then bottle for use.
desired, but for family use I never use any color.
17. Stomach Bitteus, Equal to Hostetters', for OitbpouiiTii ITS Cost, a_nd Schiedam Sciinapps Exposed. — European Gentian root \\ oz. ; orange peel 2\ nz. ; cinnamon i oz. ; anise seed ^ oz. ; coriander seed \ oz. ; cardamon seed \ oz. ; ungroimd Peruvian bark ^ oz. ; gum kino J oz. ; Lraise all these articles, and put them into the best alcohol 1 pt. ; let it stand a week and pour off the clear tincture ; then bo'l 'he dregs a few minutes in 1 qt. of water, strain, and press out f.U the strength ; now dissolve loaf sugar 1 lb. in the hot liquid, adding 3 qts. cold water, and mix witk the spirit tincture Ilist poured off, or you can add these, and let it stand on the dregs if preferred.
18. NOTE. — ScniEDAM Schnapps, Falsely so Called — It Is generally known that in Schiedam, Holland, they make the best quality of Gin, calling it " SchU.dam Schnapps;" consequently it might be expected that ur.j/rincipled men would undertake its imitation ; but hardly ceuld it have been expected thai so base an imitation would sl«.rt into existence under the guidance of a man, who, at least, calls hi-mself JumoraUe.
" Take geutian root, i lb. ; orange peel, i lb. ; puds, \ lb. ; (bui if this last cannot be obtained, ixxiua aurantior, unripe oranges,) or agaric, i lb. ; best galangal, i lb. ; centaury, } lb. ; — cost $1,20. Put pure spirit, 10 gals., upon them and let them stand 2 weeks; stir it every day, and at the end of that time put 3 gals, of this to one barrel of good whisky ; then bottle and label; and here follows the label :
AROJ^IATIC SCHIEDAM SCHNAPPS, A Stjperlattvi Tonic, JOiuretic, Anti-Dyspeptic, and Invigorating Cordial.— Tms ^Iedical Beverage is manufactured at Schiedam, m Holland, and is warranted free from every injurious property iud ingredient, and of the best possible quality.
Its extraordinary medicinal properties in Gravel, Gout, Chronic Rheumatism, Incipient Dropsy, Flatulence, Colic Pains of the Stomach or Bowels, whether in adults or infants. In all ordiqary cases of obstruction in the Kidneys, Bladder and Urinary Organs, in Dyspepsia, whether Acute or Chronic, in general Debility, sluggish Circulation of the Blood, Inadequate Assimi-
I purchased the foregoing recipe of an extensive dealer in E-vansville, Ind. ; he put up the stuff in quart bottles, and labeled it as I have shown you ; his label was got up in splendid style, bronzed letters, and sent out to the world as pure " Scfiiedam Schnapps " at $1 per bottle."
I have given you the whole thing, that the tJumsands into whose hands this book may fall, shall know what confidence, or that no confidence whatever, can be placed in the " Advertised Nostrums" of the day, but that the only security we have is to make our own, or go to those whom we know to be scientific. Obtain tlieir prescription and follow their counsel. Eveiy person knows that real Holland Gin possesses diuretic and other valuable properties ; and who would not suppose he was getting a genuine article from this Ftami7ig, Bronze-crested Label, pointing out especially all the complaints that Bchiedam-lovers are wont m complain off And yet not one drop of gin to a barrel of it. And my excuse for this exposure is that they and all who n^ay have an' occasion to use such articles, may know that " good whisky" ought to be afi"orded at less than $4 per gallon, even if $1,30 worth of bitter tonics are put into 3^ barrels of Xhe previous stuff.
Whenever you buy an article of medicine which is not regularly labeled by the Druggist, have him, m all cases, icrite the name upon it. In this way you will not only save money, but perhaps life. Arsenic, phosphorus, laudanum, acids, &c., should always be put where ch.ldren cannot get at them. And always purchase the best quality of drugs to insure success.
ALCOHOL — In Medicines, Preferable to Brandy, Rum, or Gin, of the Present Day. -There is no one thing doing so much to bolster up the tottering yet strong tower of Intemperance, as the old Pogy Physicians, who are constantly prescribing these articles to their patients,
and one-half of the reason for it is to cover the faults o^ their own constant use of these beverages. This unnecessary call for these articles thus used as a msdicine, keeps up ■d large demand ; and when we take into consideration the almost impossibility of obtaining a genuine article, the sin )i' prescribing them becomes so much the greater, when it is also known by all really scientific men that with alcohol (vyhich is pure) and the native fruit wines, cider, and cidei wines, (which every one can make for themselves, and can thus know their purity,) that all the indications desired to be fulfilled in curing disease can be accomplished without their use.
Then, when it is deemed advisable to use spirits to preserve any bitters or syrups from souring, instead of 1 qt. of brandy, rum or gin, use the best alcohol i pt., with about 2 or 3 ozs. of crushed sugar for this amount, increasing or lessening according to the amount desired in these proportions. If a diuretic effect is desired, which is calculated to arise where gin is prescribed, put 1 dr. of oil of juniper into the acohol before reducing with the water; or if the preparation admits of it you may put in from 1 to 2 ozs. of juniper berries instead of tlie oil. If the astringent effect is desired, as from brandy, use, say, J oz. of gum kino or catecliu, either, or a half of each may be usfd. If llie sireating or opening properties are required, as indicated by the prescription of rum, sweeten with molasses in place of the sugar, and use 1 dr. of oil of carraway, or 1 to 2 ozs. of the seed for the above amount, as the.iuniper berries for gin.
as preferred by the patient
Bui no one should use any of the descriptions of aWhol as » constant beverage, even in medicine, unless advised to do so by a physician w?w is not hiimelf a taper.
If families will follow the directions above gi'V'en, and use proper care in making some of the various fruit wines as given in this book for medical use, preparing ruder, &c., which is often u.-ed in prescriptions, they would sfddom, if ever, be obliged to call for the pretended pure brandies, rums, gins, &c., of commerce, and intemperance would die a natural death for want of support.
And you will please allow me here to correct a common error, with regard to the presence of alcohol in wines. It is generally supposed that wine made from fruit, without putting Bome kind of spirits into it, does not contaiu any
■Joohol ; but a greater mistake does not exist in the world. Any fruit, the juice of which will not pass into the vinous fermentation by which alcohol is produced, will not make wine at all ; distillation will produce brandy or alcohol from any of these fermented liquors.
There is no wine, of any note, containing less than 10 parts of alcohol to 100 parts of the wine ; and from that amount up U) 25i parts; currant 20^; gooseberry 1 If ; cider from 5 to 9 parts ; porter 4^ ; even small beer 1 J paits or qts. to 100 qts..
So it will be seen that every quart of fruit wine not made for medicine, or sacramental purposes, helps to build up the cauBC (intemperance) which we all so much desire not to BQCOurage. And for those who take any kind of spirits for fc'.ie sake of the spirit, let me give you the following :
\GUE MEDICINES.— Dr. Krieder's Pills.— Quinine 20 gia. ; Dover's powders 10 gi^s. ; sub-carbonate of iron 10 grs. ; mix with mucilage of gum arable and fonn into 20 pills. DoseTwo, each hour, commencing 5 hours before the chUl should set m. Then take one night and morning, until all are taken.
I cured myself of Ague with this pill after having it hang on to me for three years with all the common remedies of the day, five weeks being the longest I could keep it off, until I obtained the above pill. This was before I had studied medicine. I have cured many others with it also, never having to repeat the dose only in one case.
In attacks of Ague, it is best to take an active cathartic immediately after the first ' fit,' unless the bowels are lax, which is not generally the case, and by the time the cathartic has worked oif well, you will be prepared to go ahead with the ' cure ' as soon as you know ita periodical return
2. For very young children, nothing is better tlian 5 or 6 grB. of quinine in a 2 oz. vial with 1 table-spoon of white sugar, then fill with water. Dosb — a tea-spoon given as above, as tc time. A thick solution of licorice, however, hides the taste of the quinine quite effectually.
3. Ague Bitters. — Quinine 40 grs. ; capsicum 20 grs. ; cloves J oz. ; cream of tartar 1 oz. ; whisky 1 pt. ; Mix. Dose — 1 to 3 table-spoons every 2 hours, beginning 8 hours before the chili comes on, and 3 times daily for several days. Or, if preferred without spirits, take the following :
4. Ague Powdek. — Quinine 10 grs. ; capsicum 4 grs. ; mix and divide into 3 powders. Directions — Take one 4 hours before the chill, one 2 hours, and the third 1 hour before the chill sJiould commence, and it will very seldom commence again. Or
5. Ague Mixture without Quinine. — Mrs. Wadsworth, a few miles south of this city, haa been using tlie following Ague mixture over twenty years, curing, she says, more than forty cases, without a failure. She takes —
Mandrake root, fresh dug, and pounds it ; then sqeezes out the juice, to obtain 1^ table-spoons, with which she mixes the same quantity of molasses, is dividing into 3 equal doses of 1 table-spoon each, to be given 2 hours apart, commencing so as to take all an hour before the chill.
It sickens and vomits some, but she says, it will scarcely ever need repeating. Then steep dog-wood bark, (some call it box-wood,) make it strong, and continue to drink it freely for a week or two, at least.
6. Ague Cure, by a Clairvoyant. — There is no doubt in my mind but what there is much virtue in the following clairvoyant prescription, for I have knowledge of the value of one of the roots." See Cholic remedy :
wine glass five or six times daily.
7. Ague Cured for a Penny. — It has been discovered that nitric acid is of great value in the treatment of Intermittent Fever, or Ague. A physician administered the article in twenty-three cases of such fever, and it was succesafuJ in all but one, in interrupting the paroxysms, and there ooourred no relapse.
In the majority of cases, 5 or 6 drops of the strong acid, given ID a little gum mucilage, every 2 hours, until 60 drops had been tbken, were found sufficient to break the fever, and restore the patient to health. The foregoing confirms the following :
8. AatnE Anodyne. — Muriatic acid and laudanum, of each I oz. ; quinine 40 grs. ; brandy 4 ozs. Take 1 tea-spoon 9, 6, and ? hours before the chill, until broken ; then at 7, 14, and 21 dayn after, take 3 doses, and no relapse will be likely to occur.
I am well satisfied that any preparation of opium, as laudanum, morphine, &c., which effect the nerves, are valuable in ague medicine, from its intimate connection with, if not entirely confined to, the nervous system; hence the advantage of the first Ague pill, the opium being in the Dover's powder.
I have given this large number of preparatioiis, and follow with one or two more, from the fact that almost every physician will have a peculiar prescription of his own, and are generally free to contribute their mite for the benefit of the world ; and aa I have seen about as much of it as most book-makers, I have come in for a large share. The nature of the articles recommended are such also as to justify their insertion in this work.
9. Pebrifugei Wine. — Quinine 25 grs.; water 1 pt.; sulphuric acid 15 drops ; epsom salts 3 oz. ; brandy 1 gill ; loaf sugar 2 ozs. ; color with tincture of red sanders. Dose. — a wineglass 3 times per day.
This is highly recommended by a regular practicing physician, in one of the ague holes (Saginaw) of the west. It, of course, can be taken without any previous preparation of the system.
10. Tonic Wine Tincttjiie. — A positive cure for Ague without quinine. Peruvian bark 2 ozs. ; wild cherry tree bark 1 oz ; cinnamon 1 dr. ; capsicum 1 tea-spoon ; sulphur 1 oz. ; port wine 2 qts. Let stand a week, shaking occasionally. All the articles are to be pulverized. Dose — A wine-glass every 2 or 8 hovu-3 through the day until broken, then 2 or 3 times per day until all is used.
Always buy your Peruvian bark, and pulverize it your•elf, as most of the pulverized article is greatly adulterated. This is the reason why more cures are not perfermed by it
Soot scraped from a chimney, (that from stove pipea dnes not do,) 1 table-spoon, steeped in -water 1 pt., and settled with 1 egg beaten up in a little water, as for other coffee, with svirar and cream, 3 times daily with the meals, in place of other coffee.
Many persons will stick up their noses at these " Old (jirandmother prescriptions," but I tell many " upstart Physicians " that our grandmothers are carrying more information out of the world by their deaths, than will ever be possessed by this class of " sniffers," and 1 really thank God, 80 do thousands of others, that He has enabled me^ in this work, to reclaim such an amount of it for the benefit of the world.
12. BalmOny J of a pint basin of loose leaves, fill with boiling water and steep ; drink the whole in the course of the day, and repeat 3 or 4 day?, or until well.
It has cured many cases of Ague. It is valuable in Jaundice, and all diseases of the Liver ; and also for worms, bj the mouth and by injection. It Is also valuable in Dyspepsia, Inflammatory, and Febrile diseases, generally.
NIGHT SWEATS.— To Releive.— After Agues, Fe vers, &c., and in Consumption, many persons are troubled with " Night Sweats j" they are caused by weakness or general debility. For its relief :
gill of cold sage tea.
It should be taken two or three times during the day, and at bed time ; and the cold sage toa should be used freely aa a drink, also, until cured. It will even cure Ague, also, by repeating the above dose every hour, beginning twelve tc fifteen hours before the chill.
Fevers — General Improved Treatment ^ob Bilious, Typhoid, and Scarlet Fevers, CongestiveChills, &c. Also Valuable in Diarrhea, SummerComplaint, Cholera-Infantum, and all Forms oi Fever in Children. — The symptoms of Fever are generally understood, yet I will give the characteristic features by which it will always be detected : cold chills, followed bj
a hot skin ; a quickened pulse, with a weak and languid feeling of distress ; also, loss of appetite, thirst, restlessness, Bcanty excretions ; in fact, every function of the body is more or less deranged. Of course, then, that which will restore all the different machinery to healthy action, will restore health. That is what the following febrifuge has done in hundreds of cases — so attested to by " Old Doctor Cone," from whose work on " Fevers and Febrile Diseases," I first obtained the outlines of the treatment, and it gives me pleasure to acknowledge my indebtedness to him through fourteen years of neighborhood acquaintance, always finding him as willing to communicate, as qualified to practice, and daring, in breaking away from " Medical Society Rules," t* accomplish good.
Febkifuge for Fevers in General.— Carbonate of ammo nia 2 clrs. ; alum 1 dr. ; capsicum, foreign gentian, Colombo root, and Prussiate of iron, all pulverized, of each, i dr. ; mix, Iv putting into a bottle, adding cold water 4 ozs. Dose — One tea-spoon to a grown person, every 2 hours, in common cases of fever. It may be sweetened if preferred. Shake well each time before giving, and keep the bottle tightly corked.
The philosophy of this treatment is, the carbonate of ammonia neutralizes the acidity of the stomach, and determines to, and relaxes the surface ; and with the capsicum is a hundred per cent more efficient. The alum constringes, soothes, and aids in relieving the irritated and engorged mucous membrane of the stomach, and finally operates as a gentle laxative. The Colombo and gentian are gently astringent am stimulating, but chiefly tonic, and the Prussiate of iron is tonic ; and in their combination are, (as experience will and has proved) the most efficient and safe Febrifuge, in all forma and grades of fever, yet known. We therefore wish to sf-?te that, after twenty-five years' experience in the treatunut of disease, we have not been able to obtain a knowIftdse of any course of treatment that will begin to compare with that given above, for the certain, speedy, and effectual cure of all forms of fever ; and all that is requisite. Is, to liave sufficient confidence in the course of treatment recommended ; to use it from three to five, and in extreme eases, seven days, as directed, and that confidence will be inspired io all who use it, whether Physician (if unprejudiced) or
nature require time for their accomplishment.
After the patient has been twonty-four hours without fever, or if the patient be pale, blanched, -with a cool but face and feeble pulse, at the commencement of fever, prepare the following :
3. Febrifugh Tea. — Take Virginia snake root and valerian root, of each 2 drs. ; boiling water 1 pt. Pour the boiling water on the roots and steep i an hour, and give a tea-spoon of the Febrifuge and a table-spoon of this Tea together, every 2 hours, and after he has been another 24 hours without fever, give it every 3 or 4 hours, imtil the patient has good appetite and digestion, then 3 times daily, just before meals, until the patient nas gained considerable strength, when it may be entirely discontinued ; or he may continue the simple infusion to aid digestion.
A strong tea of wild cherry bark makes the best substitute for the snake root tea, and especially if mercury has been previously used in the case, and If it has, it is best to continue the cherry bark tea until the patient is entirely reeovered.
A patient using this treatment, if bilious, may vomit bile a few times, or if there is conjestion of the stomach, he wil; probably vomit occasionally for a few hours, but it will soon subside. It will not purge, except a patient be very bilious, in which case there will probably be two or three bilious discharges ; but it gives so much tone to the action of tl. e stomach and bowels as to secure regular operations : but if the bowels should not be moved in two or three days, give injections of warm water, or warm water with a little salt in it.
Give the patient all the plain, wholesome diet, of any kind, he will take, espcially broiled ham, mush and rich milk, boiled rice, milk or dry toast, hot mealy potatoes, boiled or roasted, with good fresh butter, &c., &c. ; and good, pure, cold water, or tea and coffee, seasoned to the taste, aa drinks, and keep the person and bed clean, and room quiet and undisturbed by conversation, or any other noise, and see that it is well ventilated.
If there should be extreme pain in the head when the fever is at the highest, or in the back or loins, and delirium at night, with intolerance of light and noise j in such cases.
8. Fevek Liniment. — Sulphuric ether and aqua ammonia, of each 1 oz ; muriate of ammonia i oz. ; mix, and shake the hot tie, and wet the scalp and all painful parts, every 2 or 3 houiB, until the pain abates. Keep tightly corked.
e renewed every three or four hours.
Besides the above treatment, dip a towel in cold water, and rub the patient off briskly and thoroughly, and be careful to wipe perfectly dry, with a clean, hot and dry towel j this may be repeated every three or four hours, if the skin be very hot and dry ; but if the surface be pale, cool, moist, livid, or lead- colored, omit the general sponging ; but tha face, neck and hands may be washed occasionally, but be sure to wipe perfectly dry with a clean, hot and dry towel. But if he be very pale and blanched, with a cool or coldsurface, or have a white circle around his mouth and nose, or be covered with a cold, clammy perspiration, give the Febrifuge every hour, until the above symptoms disappear, giving the patient hot coffee or tea, pennyroyal, sage, balm, or mint tea, as hot as he can sup them, and as freely as possible, and make hot applications to his person, and put a bottle of hot water to the soles of his feet ; and after this tendency to prostration is overcome, then give the Febrifuge once in two hours as before only.
Children will use the medicine in all respects as directed for grown persons, giving to a child one year old a fourth of a tea-spoon, or fifteen drops ; if under a year old, a little less, (we have frequently arrested Cholera Infantum with the Febrifuge, in children under six months old, and in some instances under a month old,) and increase the dose in proportion to the age above a year old, giving half a tea-spoon to a child from three to six, and three-fourths of a tea-spoon from six to ten years, old and so on ; and be sure to offef children some food several times a day, the best of which is broiled smoked ham, good stale wheat bread boiled in good
rich milk, mush and milk, boiled rice, etc. ; but animal diet agrees best, and especially in cases of Summer Complaint, or Cholera Infantum, the diet had better be almost exclusively animal. It will be difficult to use tho infusion of snake root with children that are too young to obey the mandate of parents, and the Febrifuge may be made sweet, with white or loaf sugar, for young children, so as to cover its tasce as much as possible, but older children will be benefited very much by the use of thf infusion of snake root and valerian, and should take it as prescribed for adults, of course adapt ing the dose to the age of the patient.
4. Note. — The above treatment, if persevered in for a abort time, is effectual in arresting Diarrhea, Summer Complaint, Cholera Infantum, and all forms of Fever in children. Give it every two hours, or if the patient be very feeble and corpse-like, give it every hour until there is reaction, and then give it every two hours, as prescribed for fever in general, and you 'will be satis* fled with the result after a short time.
5. Typhoid Fever. — If the patient be Typhoid, that is, if his tongue be brown or black, and dry in the centre, with glossy red edges ; if he have Diarrhea, with thin, watery, or muddy stools, and a tumid or swollen belly, he will probably have a rapid, or frequent, and small pulse, and be delirious and rest but little at night j under these circumstances, give the Febrifuge in the Tea, No. 2, as for fevers in general, every two hours, and give, also, the following :
each 4 oz.
Shake the vial, and give forty drops every four hours, in mth the other medicine, until the tongue becomes moist, and the Diarrhea is pretty well subdued, when you will discontinue this preparation, and continue the Febrifuge and snake root tea, as directed for fever in general.
Note. — We do not believe that one case of feverinathnusund will develope Typhoid symptoms, unless such cases have b^eu injured in the treatment of the first stage, by a reducing coiu^e oi' medicine, as bleeding, vomiting, especially emetic tartar, purging, especially with calomel, and compound extract of colocynth or oil, salts, or infusion of senna, and the common cooling powder, which is composed of saltpetre or nitre, and tartar emetic or ipecac, all of which irritate the mucous membrane of the
MEDICAL DEPABTMENT. S5
rfomach and bowels, and consequently produce determinatioa itf blood to these parts, that results in irritation, engorgement, iongestion, inflammation, and consequently Typhoid Fever.
Tf fever is attended witli the Dysentery, or Bloody Flux, it jhould be treated in the same manner precisely as Typhoid Fever, as it is nothing but Typhoid Fever with inflammation of the large, and sometimes small bowels. The treatment given for Typhoid Fever above, will cure all forms of Dyseu tery as it does fever, but the bloody and slimy discharges trill continue for two or three days after the fever is subdued and the appetite and digestion are restored, and at times, especially if the patient discharge bile, which will be green, there will be a good deal of pain at stool, which, however, will soon subside.
7. Scarlet Fever. — If you have Scarlet Fever, treat it in all respects as fever in general, and if the patient's throat should show any indications of swelling, apply the FeverLiniment No. 3, and make the application of cold water in the same manner as there directed ; and it had better be reoeated every three or four hours until the swelling is entirely subdued, when the wet cloth should be substituted by a warm, dry, flannel one ; but if the patient's throat should aicerate, give a few drops of the Febrifuge every half hour, or hour, until the dark sloughs separate, and the throat looks red and .clean, when you need only give the medicine at regular intervals, as recommended for fever in general, that is, every two hours. If this treatment be pursued at the onset, the throat will seldom, if ever, ulcerate.
8. Congestive, or Sinking Chill. — In case of Conges • tive, or Sinking Chill, give the Febrifuge as directed for fever in general ; but if the patient be insensible and cold, or drenched in a cold perspiration, give the Febrifuge in a tablespoon of the snake root and valerian tea every hour until the patient becomes warm, and then give it every two hours to within twelve hours of the time he anticipates another chill, when you will give the following
9. Stimulating Torac. — Sulphate of quinine 20 grs. ; pulverized capsicum 30 grs. ; pulverized carbonate of ammonia 90 grs. ; mix and put into a bottle, and add 15 tea-spoons of cold water, and give a toa-spoon, together with a tea-spoon of the Febrifuge,
enake root and valerian tea, for 15 hours.
The patient should lie in bed and drink fteely of pennyroyal tea, or hot coffee, or some other hot tea, and after the time has elapsed for the chill, give the same as for fever in general, until the patient is entirely recovered. ITie abova treatment will arrest any form of Ague, and the after treat ment will, with any degree of care, prevent its return. Or the Ague may be arrested most speedily, by taking one grai« of quinine in a tea-spoon of the Febrifuge every hour for six hours preceeding a paroxysm, and then pursue the abor« tonic course.
I have given the foregoing treatment for fevers, because 1 know that it is applicable in all cases, and that the articles are kept by all druggists. But there is a better, because quicker method of cure, and I am very sorry to say thai; for want of knowledge, in regard to the value of the medicine-, it is not usually kept by Druggists. I mean the Tincture of Gelseminum. It is an unrivaled Febrifuge. It relaxes the system without permanent j)iOstration of strength. Its tpecific action is to cloud the vision, give double-sightedness and inability to open the eyes, with distressed prostration; which will gradually pass off in a few hoars, leaving the patient refreshed, and if combined with quinine, completely restored. To administer it :
10. Take the tincture of gelseminum 50 drops, put into a vial, and add 5 tea-spoons of water ; quinine 10 ^. Suake when used. Dose — One tea-spoon in half a glass ot sweetened water, and repeat every 2 hours.
specific action as mentioned above, give no more.
Dr. Hale, of this city, one of the more liberal class of physicians, (and I use the term, liberal, as synonymous with the term, successful,) prefers to add twenty-five drops of the tincture of veratrum viride with the gelseminum, and give as there directed. And in case that their full specific action should be brought on, give a few spoons of brandy, to raise the patient from his stupor, or what is preferable :
applicable in all cases of fever, except in Typhoid accompanied with its own excessive prostration ; without the additiot of the veratrum it is applicable in all cases of fevers above described. Of course, in all cases where the fever is thus subdued, you will continue quinine, or some other appropri ate tonic treatment, to perfect a cure, and prevent a relapse. Lemonade, NouHisHiKa, Fon Fevek Patients. — Aitowroot 2 or 3 tea-spoons rubbed up with a little cold water, in a bowl or pitcher, which will hold about 1 qt. ; then squeeze in the juice of half of a good sized lemon, with 2 or 3 table-spoons of white sugar, and pour on boiling water to fill the dish, constantly stirring whilst adding the boiling water.
fer the following :
13. Prop. Hufeland's Drink for Fever Patients or Excessive Thirst. — Cream of tartar i oz. ; water 3 qts. ; boil until dissolved ; after taking it from the fire add a sliced orange witli from li to 3 ozs. of white sugar, according to the taste of the patient ; bottle and keep cool.
To be used for a common drink in fevers of all grades, and at any time when a large amount of drink is craved by iiic invalid. Neither is there any bad taste to it for those i'i heaSth,
UTERINE HEMORRHAGES.-Pbof. Piatt's Treatment Twenty Years Without a Failure. — Sugar of lead 10 grs. ; ergot 10 grs. ; (>pium 3 gre. ; epicac 1 gr. ; all pulverized and well mixed. Dose — 10 to 13 grs., given in a little honey or Byrup.
In very bad cases after child-birth, it might be repeated in thirty minutes, or the dose increased to fifteen or eighteen grains ; but in cases of rather profuse wasting, repeat it once at the end of three hours, will usually be found all that is necessary, if not, repeat occasionally as the urgency of the case may seem to require.
erust coflfee, there was but little trouble with Dyspepsia • but since the days of fashionable intemperance, both in eating and drinking, such as spirituous liquors, wines, beers, ale, tea, and coffee, hot bread or biscuit, high seasoned food, over-loading the stomach at meals, and constant eating and drinking between meals, bolting the food, as called, that is, twallowing it without properly chewing, excessive venery, want of out door exercise, with great anxiety of mind as to bow the means can be made to continue the same indulgenees, &c., all have a tendency to debilitate the stomach, and bring on, or cause, Dyspepsia.
And it would seem to the Author that the simple state ment of its cause — the truth of which no one can reason ably doubt — would be sufficient to. at least, suggest its cure But I am willing to state, that, as a general thing, this overindulgence would not be continued, nor would it have been allowed, had they known its awful consequences. I know that this was true in my own case, in all its points ; this was, of course, before I had studied, or knew but little, of the power of the human system, or the practice of medicine, and it was for the purpose of finding something to cure myself, that I commenced its study ; for it was by years of over-indulgence at table, and between meals, in the grocery business which I was carrying on, that I brought on such a condition of the stomach that eating gave me the most intolerable suffering — a feeling almost impossible to describe j first a feeling of goneness or want of support at the stomach, heat, lassitude, and fiaally pain, until a thousand deaths would have been a great relief; drink was craved, and the more I drark the more intolerable the suffering— apple cider, vinegar and water made palatable with sugar, excepted. It might be asked at this point, what did I do ? I would ask, what could I do ? Eat, I could not, drink I could not ; then what else was to be done, only, to do without either. What, starve ? No.
Treatment. — Take, — no, just stop taking " Throw all medicine to the dogs" — yes, and food also. What, sUrve ? No, but simply get liungrn/ ; whoever heard of a dyspeptic being hungry? at least, those who eat three meals a day. They eat because the victuals taste good — mouth-hunger, only.
All physicians whose books I have read, and all whose prescriptions I have obtained, say : " Eat little and often ; ^rink little and often." I say eat a little, and at the right time, that is, when hungry at the stomach j drink a little, and ac the right time, that is, after digestion, and it is of j 6t as much importance to eat and drink the right thing, as at the r ^ht timd.
Persons have been so low in Dyspepsia, that even ona tea-spoon of food on the stomach would not rest ; in such cases, let nothing be taken by mouth for several days ; bu* inject gruel, rice water, rich broths, &c. ; but these cases occur very seldom. •
First. — Then, with ordinary cases, if there is much heat of the stomach, at bed time, wet a towel in cold water, wringing it out that it may not drip, and lay it over the stomach, having a piece of flannel over it to prevent wetting the clothes. This will soon allay the heat, but keep it OP during the night, and at any subsequent time, as may be needed.
Second. — In the morning, if you have been in the habit of eating about two large potatoes, two pieces of steak, two slices of bread, or from four to six hot pancakes, or two to four hot biscuits, and drinking one to three cups of tea or foffee, — hold, hold, you cry; no, let me go on. I have nany times seen all these eaten, with butter, honey, or moiASses, too large in amount to be mentioned, with a taste of every other thing on the table, such as cucumbers, tomatoes, &c., &c., and all by dyspeptics ; but,
You will stop this morning on half of one potato, two inches square of steak, and half of one slice of cold, wheat bread — or I prefer, if it will agree with you, that you use the " Yankee Brown Bread," only the same quantity ; eat very slow, chew perfectly fine, and swalloio it witlioiit water, tea, or coffee ; neither must you drink any, not a drop, until one hour before meal-time again, then as little as possible, so as ygu think not quite to choke to death.
food taken? If you did, take less next time, or cliai»<« the kind, and so continue to lessen the quantity, or chai»^e the kind until you ascertain the proper quantity and kind which enables you to overcome this exceeding suffering after meals ; nay, more, which leaves you perfectly comfortr able after meals.
Lastly — You now have the whole secret of curing the worst case of dyspepsia in the world You will, however, bear in mind that years have been spent in indulgence ; do not therefore expect to cure it in days, nay, it will take months, possibly a whole year of self-denial, watchfulness and care : and even then, one over loading of the stomach at a Christmas pudding will set you back again for motiths. Make up your mind to eat only simple food, and that, in small quantities, notwithstanding an over-anxious wife, or other friend, will say, now do try a little of this nice pie, pudding, or other dish, no matter what it may be. Oh ! now do have a cup of this nice coffee, they will often ask j but 710, NO, must be the invariable answer, or you are again a " goner." For there is hardly any disease equally liablfl to relapse as dyspepsia ; and indulgence in a variety of food, or over-eating any one kind, or even watery vegetables or fruit, will be almost certain to make the patient pay dear foi the whistle.
Then you must eat only such food ar you know to agree with you, and in just as small quantities as will keep you in health. Drink no fluids until digestion is over, or about four hours after eating, until the stomach has become a little strong, or toned up to bear it, then one cup of the " Dyspepsia Coffee," or one cup of the " Coffee Made Healthy," ma-s be used. But more difficulty is experionced from ovordrinking, than over-eating. Most positively must Dvspept'cs avoid cold water with their meals. If the saliva and gastrio juice are diluted with an abundance of any fluid, they nerer have the same properties to aid, or carry on digestion, which they had before dilution ; then the only hope of the DyS' peptic is to use no fluid with his food, nor until digestion has had her perfect work.
ATKMgli for health — two, and even three, are often eaten. Most persons have heard of the lady who did not want a ^' cart load," but when she got to eating, it all disappeared, and the retort, " Back up yo\ir cart and I will load it again," was /ust what I would have expected to hear if the load had beeti given to a Dyspeptic, which it no doubt was ; then learix the proper amount of food necessary for health, and wheu that is eaten, by yourself or child, stop. If pudding is on the table and you choose to have a little of it, it is all right -have some pudding ; if pie, have a piece of pie ; or cake, have a piece of cake ; but do not have all, and that after you have eaten twice as much meat victuals as health requires. If apples, melons, raisins or nuts aie on the table, and yoa wish some of them, eat them before meal, and never after iij if surprise is manifested around you, say you eat to live, not live to eat. The reason for this is, that persona will eai> all they need, and often more, of common food, then eat nuts, raisins, melons, &c., until the stomach is not only filkot beyond comfort, but actually distended to its utmost capacity of endurance ; being led on by the taste, when if the reverse course was taken, the stomach becomes satisfied when a proper amount of the more common food has been eaten, atter the othei-s.
Are you a Grocer, and constantly nibbling at raisins, candy, cheese, apples, and every other edible ? Stop, until just before meal, then eat what you like, go to your meal, and return, not touching again until meal-time, and you are safe ; continue the nibbling, and you do it at the sacrifice of future health. Have you children or other young persons under your care 1 See that they eat only a reasonable quantity at meals, and not anything between them j do this, and I am willing to be called a fool by the younger ones, which I am sure to bo , but do it not, and the fool will suffer for his folly.
voice, or gpare the guilty.
In recent cases, and in cases brought on by over-indulgence, at some extra rich meal, you will find the " Dyspeptic Tea," made from " Thompson's Composition," will be all sufficient, as spoken of under that head, which see.
2. The wild black cherries, put into Jamaica rum, i* highly recommended, made very strong with the cherries, and without sugar ; but I should say put them into some ot the domestic wines, or what would be still better, make a wine directly from them, according to directions under th« head of " Fruit Wines."
3. Old " Father Pinkney," a gentleman over 90 years of age, assures me that he has cured many bad cases of Dyspepsia, where they would give up their over indulgences, by taking :
Blue flag root, washed clean, and free from specks and rotten streaks, then pounding it and putting into a little warm water, and straining out the milky juice, and adding suflScient peppersauce to make it a little hot. Dose — one table-spoon 3 times daily.
It benefits by its action on the liver, and it would be good in Liver Complaints, the pepper also stimulating the stomach. See " Soot-Cofiee " No. 12, amongst the Ague medicines.
LARYNGITIS, — Inflammation of the Throat. — This complaint, in a chronic form, has become very prevalent, and is a disease which is aggravated by every change of weather, more especially in the fall and winter months. It is considered, and that justly, a very hard disease to cure, but with caution, time, and a rational course of treatment, it can be cured.
The difficulty with most persons is, they think that it is an uncommon disease, and consequently they must obtain some uncommon preparation to cure it, instead of which, some of the more simble remedies, as follows, will cure nearly every case, if persevered in a sufficient length of time. First, then, take the :
Alterative for Diseases of the Skln. — Compound tino ture of Peruvian bark 6 ozs. ; fluid extract of sarsaparilla 1 ll». ; extract of conium i oz. ; iodide of potash, (often called hydrio .date) i oz. ; iodine i dr. ; dissolve the extract of conium and thi
In the next place, take the :
2. GARGiiic FOB Sore Throat. — Very strong sage tea i pt. , strained honey, common salt, and strong yinegar, of each 2 tablespoons ; cayenne, the pulverized, one rounding tea-spoon ; steeping the cayenne with the sage, strain, mix, and bottle for use, gargling from 4 to a dozen times daily according to the severity of tht ease.
Tllis is one uf the very best gargles in use. By persevering some three months, I cured a case of two years standing where the mouths of the Eustachian tubes constantly discharged mattei at their openings through the tonsils into the patients mouth, he having previously been quite deaf, the whole throat being also diseased. I used the preparation for ** Deafness " albo as mentioned under that head.
for the breath, the nose.
Besides the foregoing, you will wash the whole surface twice a week with plenty of the " Toilet Soap," in water, wiping dry, then with a coarse dry towel rub the whole surface for ten minutes at least, and accomplish the coarse towel part of it every night and morning until the skin will remain through the day with its flushed surface, and genial heat ; this draws the blood from the throat and other internal or gans^ or in other words, equalizes the circulation ; know, and act, upon this fact, and no inflammation can long exist, no matter where it is located. Blood accumulates in the part inflamed, but let it flow evenly through the whole system, and of course there can be no inflammation.
8. Sore Throat Liniment. — Gum camphor 2 ozs. ; castile soap, shaved fine, 1 dr. ; oil of turpentine 1 table-spoon ; oil of origanum i oz. ; opium i oz. ; alcohol 1 pt. In a week or ten davs it will be fit for use, then bathe the parts freely 2 or 3 times daily.
This liniment would be found useful in almost any throat or other disease where an outward application might be needed. If the foregoing treatment should fail, there is no alternative
tinue them for a long time.
I mention the emetic plan last, from the fact that so many people utterly object to the emetic treatment. But when everything else fails, that stepss in and saves the patient, which goes to show how unjust the prejudice. By the phrase, a long time, I mean several weeks, twice daily a< first, then once a day, and finally thrice to twice a week, &c A part of this course you will see, by the following, is cor roborated by the celebrated Lung and Throat Doctor, S. S. Fitch, of New York, who says " ft is a skin disease, and that purifying medicines are necessary to cleanse the bloodtaking long, full breaths," &c. This is certainly good sense. His treatment of throat diseases is summed up in the following :
Note. — " Wear but little clothing around the neck — chew often a little nut-gall and swallow the juice — wear a wet cloth about the throat at night, having a dry towel over it — bathe freely all over as in consumption, and especially bathe the throat with cold water every morning, also wash out the inside of the throat with cold water — avoid crowded rooms — gargle with a very weak solution of nitrate of silver — chewing gold thread and swallowing the juice and saliva from it — borax and honey occasionally, and gum arable water, if much irritation — use the voice as little as possible until well, also often using a liniment externally."
I had hoped for very much benefit from using croton oil externally, but time has shown that the advantage derived from it is not sufficient to remunerate for the excessive irritation caused by its continued application.
4. Smoking dried mullein leaves in a pipe not having been used for tobacco, is said to have cured many cases of Laryngitis. And I find in my last Eclectic Medical Journal so strtng a corroboration, taken from the Medical and Surgical Reporter, of this fact, that I cannot refrain from giving tho quotation. It says : " in that form of disease ia which there is dryness of the trachea, with a constant desire to clear the throat., attended with little expectoration, and considerable pain in the part afiected, the mullein smoked through a pipe, acts like a charm, and affords instant relief. It seems to act as an anodyne in allaying irritation, while it promotes expectoration, and removes that gelatinous mucus
wliioli gathers in the larynx, and, at the same time, by some unknown poioer, completely changes the nature of the diaease, and, if persevered in, will produce a radical cure/'
We read in a certain place of a gentleman who was walk iug around and through a great city, and he came across an inscription " To the unknown God " — and directly we find him explaining that unknown Being to the astonished inhabitants. And I always feel, like this old-fashioned gentleman, to cry out, upon every convenient occasion, my belief, that it was that God's great wisdom, seeing what waa required, and His exceeding goodness, providing according to our necessities, this wonderful, and to some, that unknown power in the thousands of plants around us. What matters U to us ho*7 it is done ? If the cure is performed, it is suffi cient.
Since the publication of the foregoing, in the ninth edi tion, I have been smoking the dried mullein, and recommending it to others. It has given general satisfaction for coughs and as a substitute for tobacco in smoking, exhilerating the neives, and allaying the hacking coughs from recent colds, by bioathing the smoke into the lungs. In one instance, aftei retiring, I could not rest from an irritation in the upper portion of the lungs and throat, frequently hacking without relief only for a moment ; I arose, filled my pipe with mullein, returning to bed I smoked the pipeful, drawing it into ilie lungs, and did not cough again during the night.
An old gentleman, an inveterate smoker, from my suggestion, began to mix the mullein with his tobacco, one-fourth at first, for awhile j then half, and finally three-fourths ; at this point he rested. It satisfied in place of the full amount of tobacco, and cured a cough which had been left upon him after inflammation of the lungs. The flavor can hardly be distinguished from the flavor of tobacco smoke, in rooms.
It can be gathered any time during the season, the centre Btem removed, carefully dried, and rubbed fine, when it is ready for use. It gives a pipe the phthysic, as fast as it cures one on the patient ; but the clay pipe, which is to be osed, can be readily cleansed by burning out.
(Surqeon-Gteneral of the Neapolitan Army) and several Successful American Methods. — The principle upon which the treatment is based, consists in transforming a tumor of a malignant character, by conferring upon it a character of benignity, which admits of cure. This transformation is effected by cauterization with an agent looked upon as a specific, viz : chloride of bromine, combined, oi not, with other substances, which have already been tried, but have hitherto been employed separately. The iniernal treatment is merely auxiliary. (Cancers may be known from other tumors by their shooting, or lancinating pains ; and if an open sore, from their great fetor. — Author.) The formulas for the caustics are, with the exception of a few cases, the following :
mixed with a sufficient quantity of flour to form a viscid paste.
At Vienna, he used a mixtui'e of the same substances in different proportions, chloride of bromine 3 parts ; chloride of zinc 2 ;aarts ; chloride of gold and antimony, each 1 part ; made into a thick paste with powdered licorice root. This preparation should be made in an open place, on account of the gases which are disengaged.
The essential element is the chloride of bromine, which has often been employed alone ; thus, chloride of bromine from 2i to 4 drs., and put licorice root as much as sufficient.
The ehloride of zinc is indispensable in ulcerated cancers, in which it acts as a hemastatic, (stopping blood.) The chloride of gold is only useful in cases of encephaloid (brain- like) cancers, in which it exercises a special, if not a specific action. Cancers of the skin, (epitheliomas,) lupas, and small cystosar comas, (watery or bloody tumors,) are treated with bromine mixed with baailicon ointment in the
proportion of one part of bromine to eight of the ointment ; the application should not extend to the healthy parts, it« gction being often propagated through a space of one or two lines. The paste is only allowed to remain on about twentyfour hours J on removing the dressing a line of demarkation is almost always found separating the healthy from the morbid parts. The tumor ia itself in part whitish and part reddish, or marbled with yellow and blue. The caustic is replaced with the poultice, or with compresses smeared with basilicon ointment only, which are to be removed every three hours until the scar is detached ; the pain progressively diminishing in proportion as the mortification advances, the line ot demarkation daily becomes more evident j about the fourth or fifth day the cauterized portion begins to rise, and from the eighth to the fifteenth day it becomes detached, or can be removed with forceps, and without pain, exposing < a suppurating surface, secreting pus of good quality and covered with healthy granulations. If any points remain of less satisfactory appearance, or present traces of morbid growth, a little of the paste is to be again applied, then dres. the sore as you would a simple ulcer; if the suppuratioc proceeds too slowly, dressit with lint dipped in the following, solution :
In the majority of cases healing takes place rapidly, cicatrization progressc*3 from the circumference to the center, no complications supervene, and the cicatrix (scar,) resembles that left by a cutting instrument. His internal remedy, to prevent a relapse, is,
Chloride of bromine 2 drops; powder of the seeds of water fennel 23 grs. ; extract of hemlock (Conium Maculatum) 12 grs. ; mix and divide into 20 pills ; onjs to be taken daily for 2 months, and after that, 2 pills daily for a month or two longer, 1 night and morning, after meals.
In any case of Cancer, either the foregoing, internal remedy, or some of the other Alteratives, should be taken two or three weeks before the treatment is commenced, and should also be continued for several weeks after its cure.
Chloride of zinc the size of a hazel nut, and pats enough watei TvJlh it to make a thin paste, then mixes with it equal parts of flour, and finely pulverized charcoal, sufficient to form a tolerable siifl' paste.
8. L. S. HoDGKiNs* Method. — This gentleman is a merchant, of Eeding, Mich. The method is not original with him, but he cured his wife with it, of cancer of the hreasi, after having been pronounced incurable. Some vrould use it because it contains calomel — others would not use it fo! the same reason; I give it an insertion from the fact that 1 am well satisfied that it has cured the disease, and from its singularity of composition.
Take a while oak root and bore out the heart and bum th^ chips to get the ashes, i oz. ; lunar caustic i oz. ; calomel J oz. , gaits of nilre (salt petre) f oz. ; the body of a thousand-legged worm, dried and pulverized, all to be made fine and mixed with I lb. of lard.
Spread this rather thin upon soft leather, and apply to the Cancer, changing twice a day j will kill the tumor in three or four days, which you will know by the general appearance ; then apply a poultice of soaked figs until it comes out, fibres and all ; heal with a plaster made by boiling red beech leaves in water, straining and boiling thick, then mix with beeswax and mutton tallow to form a salve of proper consistency. To cleanse the system while the above is being dsed, and for some time after:
Take mandrake root, pulverized, 1 oz. ; epsom salts 1 oz. ; put Into pure gin 1 pt., and take of this 3 times daily, from 1 tea to a table-six)on, as you can bear. He knew of several other curea from the same plan.
4. The juice of pokeberries, set in the sun, upon a pewter dish, and dried to a consistence of a salve, and applied as a plaster, has cured cancer.
5. Poultices of scraped carrots, and of yellow dock root, have both cured, and the scraped carrot poultices, especially, not only cleanse the sore, but remove the very offensiv» smell or fetor, which is characterittic of canceiB.
6. A gentleman in Ohio cures tliem by making a tea of ihe yellovr dock root, and drinking of it freely, washing the sore with the same several times daily for several days, then poulticing with the root, mashed and applied twice daily, even on the tongue.
has kuovFn several cases cured as follows :
Take the narrow-leaved dock root and boil it in soft watei umil very strong, wash the ulcer with this strong decoction 3 times in tlie 2i hours, fill the cavity also with the same 2 minutt.sj, each lime, ihxin bruise the root, and lay it on gauze, and lay the gau'se next to tue ulcer, and wet linen clotlis in the decoction and liiy over the poulUce ; and each time let the patient drink a wine- glass of the Strom tea of the same root, with ^ of a glass oi port wine sweetcnoJ with honey.
days, as follows :
Dilute nitric acid 1 oz ; honey 2 ozs. ; pure water 2 pts. ; mix. Dose — Three table-spoons frequently; to be sucked past tha teeth, through a quill or tube.
Lowell Mason was cured, is as follows :
Take chloride of zinc, blood-root pulverized, and flour, equal quantities of each, worked into a paste and applied until the mass comes out, then poultice and treat as a simple sore.
The Rural New Yorker, in reporting this case, says, in applying it, " First spread a common sticking-plaster much larger than the cancer, cutting a circular piece from the center of it a little larger than the cancer, applying it, which exposes a narrow rim of healthy skin ; then apply the cancer piaster and keep it on twenty-four hotirs. On removing it, the cancer wi'.l be found to be burned into, and appears the color of an old shoe-sole, and the rim outside will ap pear white and parboiled, as if burned by steam.
10. Armenian Mkthod. — lu Armenia, a salve, made by boiltag olive oil to a proper consistence for the use, is reported by an eastern traveler to have cured very bad ca^es.
11. Figs boiled in new milk until tender, then split and ap plied hot — changing twice daily, washing t})C parts every change, with some of the milk — diiuking 1 gill of the milk also at often.
And continueing from three to four months, is also reported to have cured a man ninety-nine years old by using only six pounds, whilst ten pound.s cured a cjise of ten jears* standing. The first application giving pain, but afterwards relief, every application.
12. Red Oak Bark — A salve from the ashes, has long been credited for curing cancer, and as I have recently seen the metliod given for preparing and using it, by Isaac Dillon, of Oregon, published in a paper near him, I cannot keep the benefit of it from the public. . The directions were sent to him by his father, John Dillon, Sen., of Zanesville, O., and, from my knowledge of the Dillon family, I have the utmofit confidence in the prescription. It is as follows :
Take red oak bark ashes 1 peck ; put on to thera, boiling water G qts. ; let it stand 12 hours ; then draw ofl' the ley and boil to a thick salve ; spread this, pretty thick, upon a thick cloth a little larger than the cancer, and let it remain on 3 houre; if it Is too severe, half of that liuie ; the same day, or the next, applj a^ain 3 hours, whicli will generally etlect a cure; after the last plaster, wa.sh the .soie with warm milk and water; then apply a healing salve made of muitou t4illow, bark of elder, with a iittl« umn and bees-wax, (some root of while lilly may be added,) stewed over a slow lire; when the sore begins to matterale. wash it 3 or 4 times daily, renewing the salve each lime; avoid slrong diet, and strong drink, but drink a tea of sassafras root iiid spice- wuod tops, tor a week before and after the plaster.
13. Puoip. R. S. Newton, of Cincinnati, uses the chloride of zinc, a saturated solution, (as strong as can be made,) or makes the chloride into a paste, with thick gum solution.
In eases of large tumors he often removes the bulk of them with a knile, then applies the solution, or paste, as he thinks best, to destroy any remaining roots which have been sftveied by the knile.
14. Prof. Calkins, of Philadelphia, prefers a paste made firom yellow-dock, red -clover, and poke, using the leaves' only, of either article, in equal quantities.
Boiling, straining, and simmering to a paste, applying from time to time, to cancerous growths or tumors, until tlie entire mass is destroyed, then poultice and heal as usoa)
But Dr. Beach, of N. Y., who is a man of much experi fince in cancers, «ays beware ol' the kuife, or any plastej whioa ilestroi/H the cancer or tumor ; but first use discutients (meaicines wliich have a tendency to drive away swellings,) unless already ulcerated, then, mild poultices to keep up a dlcciiarge from the ulcer, with alteratives, long continued, kebpiag the bowels regular, &c., &c. The Vienna }'Jiysi cians, as well as Dr. Beach, allow the inhalation of a few drops of chloroform where the pain is excruciating. And i would say, apply a little externally, also, around the sore.
time w bey in with them.
COiSVfVENESS— To Cure.— Costive habits are often brought oiTi by neglecting to go to stool at tlie usual nine ixix most persons liave a regular daily pas.sage, and the iiulsi usual time is at rising in the morning, or immediately aitei breakfast ; but hurry, or negligence, for the want of an un derstanding of the evil arising I'rom putting it off. these callh of nature are suppressed j but let it be understood, nafurtlike a good workman or student, has a time for each duty ; then not only let her work at her own time, but if tardy j;o at this time and uot only aid but solicit her call, or iu otiun words :
"Hie above with .attention to diet, using milk, roasted apples ■ivA if not dyspe|)tic, uncooked apples, pears, peaciies, tfcc., at meal time, '• "^'ankeo Brown Bread," or bread made of unbolted wiieat, if preferred, and avoiding a meat diet, will in most caaef ■oon remedy the difficulty. However:
2. 'n vkuy OnsTif atr Cases — Take extract of henbane i di. , extract »rc<il<>cynih * dr., extract of nux vomica 3 grs. ; carefully w Ilk into pill nia&s and form into 15 pills. Dose — one piil iiighi and monung.
After it has stood for several days, t;ike a table-spoon of it three times daily, before eating, until it operates, then hali tile (ju:intit,y, or a little less, just sufficient to establish a daily ae.ion of the bowels, until all is taken. Or, the second pill under the head of Eclectic Liver Pill may be taken as an liltenitive to bring about the action of the liver, which is, of course, more or less inactive in most cases of long continued costiveiicss.
4. Corn .Meai< — 1 table-spoon stirred up in sufflcient cold vialer to drink well, and drank in the morning, innnediaiely aflei risiufr, Lfis, with pei-severance, cured many l)ad cases.
5. A Fresh Egg — Beat in a gill of water and drank on rising in the morning, and at each meal, for a week to ten days, has cured obstinate cases. It might be increased to two or three at a time, as the stomach will bear.
CHRONIC G(^UT— To Curk.— " Take hot vinegar, and put iiiio it all the table salt which it will uissolve, and bathe the parts affected with a sotY piece of flannel. Uub in with the hand, and dry the fool, &c., by the fire. Repeal this operation four times in the 24 hours, 15 minutes each time, for four days ; then twice a day for the same period ; then once, and follow this rule whenever the symptoms show themselves at any future time.'
The philosophy of the above formula is as follows : Chronic g<mt proceeds from the obstruction of the free circulation oi the blood (in the parts affected) by the deposit of a chaiky 3ubst;incc, which is generally understood to be a carbouaie and phosphate of lime. Vinegar and salt dissolve these ; and the old chronic compound is broken up. The carbonate of lime, &c., become acetate and muriate, and these being soluble, are taken up by the circulating system, and di»i harged by secretion. This fact will be seen by the g<iuty joints becoming less and less in bulk until they assume their natural size. During this process, the stomach and bowels should be occasionally regulated by a gentle purgative. Abstinence from spirituous libations; exercise in the open air, and especially in the morning; freely bathing the whole surface ; eating only the plainest food, and occupying the time by study, or useful employment, are very desirable asBifitants.
2, GooT Tincture. — Veratnim viride, (swamp hellebore) \ oz. ; f>piiiin i <)Z. ; wine ^ pi. ; let them stand for several days. Dose — 15 to 30 drop.s, acronliiig to the robustness of tiie patient, at intervals of two to four hours.
M. Husson, a French officer, introduced this remedy in gout some sixty years ago, and it became so celebrated that it sold as high as from one to two crowns a dose. It is considered valuable also in acute rheumatism. In gout it removes the paroxysms, allays pain, and procures lest and sleep, reduces the pulse and abates fever.
3. Ooffee has recently been recommended, not only for Erout, L»ut gravel also. Dr. Mosley observes^ in his " Treatise on Coffee," that the great use of the article in France is supposed to have abated the prevalence of the gravel. In the French colonies, where coffe is more used than in the English, as well as in Turkey, where it is the principal beverage, not only ti>e gravel but the gout is scarcely known. Dr. Faar relates, as an extraordinary instance of the effect of 3oft"be on goiH the case of Dr. Deveran, who was attacked with gout at th<> age of twenty-five, and had it severely till he was upwar/e of fifty, with chalk stones in the joints of his hands ani< feet ; but for four years preceeding the time when the tu-zrount of his case had been given to Dr. Faur to lay befor*- the public, he had, by advice, used coffe, and had 00 ret-int of the gout afterward.
PA r-A LYSIS,— If Recent— To Cure.— When paralysif--. /^numb palsy) has existed for a great length of time, but little benefit can be expected from any treatment ; but if recent, very much good, if not a perfect cure will be the result of faithfully governing yourself by the following direcvions with this :
Paralytic Liniment.— Sulphuric ether 6 ozs. ; alcohol 2 ozs. ; laudanum 1 oz. ; oil of lavender 1 oz. ; mix and cork tightly. In a recent case of paralysis let the whole extent of the numb surface be, thoroughly bathed and rubbed with this preparation, for several minutes, using the hand, at least 3 times daily, at the same lime tai\e internally, 20 drops of the same, in a little sweetened water, to prevent translation upon some internal organ.
It may be used in old cases, and, in many of them, will undoubtedly do much good ; but I do not like to promise what there is no reasonable chance to perform. It is weJJ
in very recent cases to keep the parts covered with flannels with a large amount of t'rictiun by the hand ; also, elect ricitj scientilicaliy applied, that is by a Physician or some one \vh(i lias studied the nature and operations of the electrical ma chine.
This liniment should be applied so freely, that abtut an ounce a day will be consumed, on an arm or leg, and if a whole side is palsied, proportion oily more. In cases of pain:' in the stomach or side a tea-spoon will be taken with unusual success ; or for pain in the head, apply to the surface, always bearing in mind that some should be taken internally wlmnever an external application is made. la sprains and bruise? where the surfoce is not broken it will be found very efficacious. It may be, successfully, rubbed over the seat of anj internal disease accompanied with pain.
are enlarged from colds, or epidemic sore throat.
Take No. six 1 oz. ; molasses 2 ozs. ; and liot water 4 ozs. . mix and sip a little into the throat often, swallowing a little al%), it keeps up a discharge of saliva from those parts and iluis relieves their swollen condition ; and stimulates to renewed heallhj action.
It has proved very efficacious in the above epidemic cases, which leave the tonsils much indurated (hardened), as well IS swollen, with a tendency to chronic inflammation of the whole larynx, or throat, often with little ulcers. In thai case :
Put I'J grs. of nitrate of silver to 1 oz. of water with 3 or 4 drops of creosote, and swab the throat with it, and lay a tlaunel wet with turpentine upon the outside.
The worst cases will shortly yield to this mild treatment Should there, however, be a disposition to fever, you might also put the feet into hot water fifteen or twenty minutes with occasional sponging the whole surface.
SICK HEAD ACHE— To Curk.— Sick head ache, pioper, arises from acidity, or over-loading the stonnich ; when it is not from over eating, all that is necessary, is to soak the feet in hot water about twenty minutes, drinking at the same time some of the herb-teas, such s^s oen ay royal catnip, oi mint, &c., then get into bed, caver up warm and keep up a
Tweating process for about an hour, by which time relief will have been obtained ; but when food has been taken which remains in the stomach, it is much the best way to take an ametic, and the following is the :
2. Eclectic Emetic— Which is composed of lobelia, and ipecacuanha, equal parts, and blood root half as much as of sither of the others, each pulverized sei)arately, and mix tl;oroughly. DoBE- Half a common tea-spoon every 15 or 20 min ates in some of the warm teas, for instance, camomile-flowers, pennyroyal, or boneset — drinking ft-eely between doses of the same tea in which you take it; continue until you get a free and full evacuation of the contents of the stomach.
After the operation, and when the stomach becomes a little settled, some nourishment will be desired, when any of the mild broths, or gruel, should be taken, in small quantities, without fear of increasing the difficulty.
" There is, probably, no emetic surpassing this, either in eflBcacy of action, or efficiency in breaking up morbid, unhealthy conditions of the s^^stem generally ; and exciting healthy action. It is excellent in croup, chronic affections of the liver or stomach, (fcc, and in fact, when and where ever an emetic is needed." — Beach.
But after a full trial of both, upon my own person and others, 1 prefer lobelia seed alone, pulverized when used. The manner of administering them has been the cause of bringing the lobelia emetic into disrepute. I take " Thompson's Composition" tea, made as there directed and drink two saucers of it, fifteen minutes apart, and with the third I stir in one rounding tea-spoon of lobelia seed, pulverized, •and drink it; then every fifteen minutes I take another saucer of 'the tea until free vomiting takes place, not taking any more of the lobelia ; by this course I think it more efficient and thorough than the mixed emetic, and entirely free from danger of the " alarming symptoms," as they are called, brought on by continuing to give the lobelia every few minutes instead of waiting its action, and all for want of knowledge as to what that action should be ; but if you give it its own time, continuing the stimulating tea, it will have its Kp,'ci/ic action, which is to vomit, no matter at which end it is introduced. When it begins to vomit it will generally continue its action until it eiiijities the stomach, then 1 begin to substitute the composition with :
8. Brkad Tea, Used vs Takivo Emetics.— Made by takings piece of dry bread and crumbing it into a bowl, with a liliiewiil, pepper, and butter, to suit the taste, tlien pouring boiling water upon it ; this soon allays the retching, and strengthens the stomach to renewed healthy action.
Periodical Headache. — There are those who have sick headache coming ou at periods of from a i'ew weeks to i^o or three months, lasting two or three days, accompaiiicd with nausea, and occasionally with vomiting. In these caspr after using the cmotic to relieve the present attack, take the Cathartic Syrup next following :
4. CATnARTic Syrup. — Best senna leaf loz. ; jalap ior.; butternut, the inner bark of the root, dried and bniised, 2 oz. ; peppeimint leaf i oz. ; tennel seed i oz. ; alcohol ipt. ; wjiler 1^ pts. ; sugar 2 lbs. ; put all into the spirit and water, except the sugar, and let it stand 2 weeks, then strain, pressing out from the dregs, adding the sugar and siuimeriug a few minutes only, to form the syrup. If it should cause griping in any case, increase the fennel seed and peppermint leaf. Dose — One tablespoon, once a day, or less often if the bowels become too loose, up to the next period when the headache might have been expected, and it will not be forthcoming.
Tliis is a mild purgative, and especially pleasant. Most pei-sons, after a trial of it, will adopt it for their genera) cathartic, and especially for children. Increase or lessen the dose, according to the effect desired.
Females in a weak and debilitated condition, often have a headache which is purely sympathetic ; this they will distinguish by their general weakness, irregularities, and lightheadedness, often amounting to real pain ; in such cases take the following :
■>. Headache Drops. — Castor, gentian, and valerian roots, bruisod, i oz. ; laudanum 1 oz. ; sulphuric ether 1 j oz. ; alcohol i pt. ; water ^ pt. ; put all into a bottle and let stand about 10 iays. Dose — A tea-spoon as often as required, or 2 or 3 timea daily.
6. TrNCTURE OF Blood-Root. — TVIade by putting 1 oz. of the liied, bruised root, to 1 pt. of gin, and taking 1 tea-spoon, befoi« eating, every morning, and only eating a reasonable amount of "easily digested food :
Has worked wonders in cases where headaches had beea ot very long standing. And it might not be amiss to say that the majority of headaches are found amongst those who are disposed to Dyspepsia, by long continued over-eating,
hiilows :
7. " Charcoax, a Cure for Sick Headache. — It is stated that two tea-spoons of tinely powdered charcoal, drank in half a tumbler of water, will, in less than 15 minutes, give relief to the sick headache, when caused, as in most cases it is, by superabundance of acid on the stomach. "We have tried this remedy lime and again, and iis efficacy in every instance has been signally satisfactory."
AV'hen headache lias been brought on by eating too freelj of boiled beef, cabbage, &c., or any other indigestible dinner, one cup of " good tea," at tea time, eating only a slice of dry bread, will often allay the nervousness, quiet the head, and aid in getting to sleep. The " Good Samaritan '' applied to the head is also good. .
patient desires.
The jail physician of Chicago reports thirty-six favorable cases treated as above. In Boston, at the " House of Correction," the danger arising from the sudden loss of their accustomed stimulus, according to Puritanic economy, if overcome by administering, freely, a strong decoction of wormwood.
Prof. King, of Cincinnati, 0., says that from two to foui powders of the above anodyne, will nearly every time produce sleep in this whisky delirum.
TYPHUS FEVER.— To Prevent Infection.— Take nitre, (salt petre,) pulverized, J oz. ; oil of vitriol f oz. ; put the nitrp into a tea-cup and set it on a red hot shovel, adding the vitriol one-si.xth at a time, stirring it with a pipe stem; avoiding the (umes as they rise from the cup ; no danger, however, in breathing the air of the room.
The above amount is suiBcient for a room twelve by six teen feet, and less or more according to the size of olliei rooms. Dr. J. C. Smith, of Loudon, is said to have re^
solved from Parliament £5000 for making this recipe pnblio L. To purify the air from noxious effluviji in sick room*, aot of a contajiious character, Bimply slice three or f(Mir jnions, place them on a plate upon the floor, changing them ohree or four times in the twenty-four hours.
;{. DrsiNFKCTANT, FOR R00M8, Meat, AND B'isH. — CommoD lalt \ a tea-cup; sulphuric acid 2 or 3 oz. ; put alxnU \ oz. of )f tlu* acid upon the salt at a time, every 15 minutes, stirring, 'jutii all put on :
Which will purify a large room ; and for meat or fish, hang them up in a box having a cover to it, and thus confine tlie g;i8, and tainted articles of food will soon be purified, by the same operation. And notwithstanding so much waa paid for the " Smith Disinfectant," the above will be found e(jually good.
4. Coffee, dried and pulverized, then a little of it sprinkled upon a hot shovel, will, in a very few minut^ clear a room of all impure effluvia, and especially of an animal character.
5. Chloride op Lime — Half a saucer of it, moistened with an equal mixture of good vinegar and water, a few drops at a time only, will purify a sick-room in a few min utes.
SWEATING PREPARATI()N8.-^SwEATrN-o Dkops.— Ipecacuanha, saffron, Virs^inia snake root, and camphor gum. each % i>7.s. ; opium J oz. ; alcohol 3 qts.. Let stand 2 weeks, shaking occasionally. Dose — A tea-spoon in a cup of hot pennyrcjya!, spearmint, or catnip tea, every lialf hour, until perspiration is induced ; then once an hour, for a few hours.
the same time.
2. Sweating with TJcrning Alcohol.— Pour alcohol into a sancir, to about half fill it; place this under a chair; strip the person, to be sweated, of all clothing, and place him in the chair, putting a comforter over him, also ; now light a match and throw into the saucer of alcohol, which sets it on fire, and by the time the alcohol is burned out he will be in a protiise perspiration, if not, put in half as much more of alcohol and fire it again, which will accomplish the object; then rise up and draw the comforter around you, and get into bed, following up with hot teat and sweating arop8,-as m the first above.
MfemCAIi DfiPAaXMENT. 109
This last plan of sweating is also good in reusut colds, jiteurisy, inflammation of the lungs, and all othei inflammatory diseases, either in recent attacks, or of loLg standing jomplaints. See the closing remarks after the tueatmcnt ot < I'ieurisy," aUo " Ginger Wine."
IMPERIAL DROP,— For Gba\'EL and Kidjjey Complaints.— Take saltpetre 1 oz. ; putting it into an iron mortar, dropping in a live coal with it, which sets it on fire ; stir it iround until it all melts down into the solid form, blow out the coals, and pulverize it; then take an equal amount of bi-carbon&te of potassia, or galcratus, and dissolve both in soft water 2 OL-8. Dose — from 20 to 30 drops, morning and evening, in a B\vaUow of tea made from flax seed, or a solution of gum arabit^
In connection with the drops, let the patient take from A table-spoon to two or three table-spoons of onion juice — that is, all the stomach will bear — eating all the raw oniona he can, and continue it until free of the complaint. I have seen gravel the size of a common quill, crooked, and one and one-fourth inches in length, which a lady passed from the bladder, and smaller bits almost innumerable, by the eimple use of onion juice alone.
The onion juice, (red onions are said to be the best,) has, and may be injected through a catheter into the bladder ; have no fears to do this, for I know a physician of forty years' practice who has done it five times with Buccess — a physician, however, would have to be called to introduce the catheter.
2. In what is termed " Fits of the gravel," that is, where small gravel has become packed in the ureter, (tube which leads from the kidney to the bladder,) causing excruciating pain in that region, a pill of opium must be given, varying in size from one to three grains, according to the pain, strength, and age of the patient.
3. A strong decoction made by using a large handful of smart v>ecd, adding a gill of gin, and a gill each "of horse mint and onion juices, and taking all in 12 hours, has been known to discharge gravel in large quantities. — Philadelphia Eclectic Journal
The surest sign of gravel is the dark appearance of tha arine, as if mixed with coffee grounds, and a dull pain in the region of the kidney — if only inflamation, the darkness will not appear. Sec the closing remarks upon Gout.
aceti tallow 1^ om. ; oil of sweet almonds 4 tea-spoons ; grxm camphor J oz. ; made fine. Set on the stove until dissolved, constantly stirring. Do not use only just suflScient heat to melt them.
W' hilst warm, pour into moulds if desired to sell, then paper and put up in tin foil. If for your own use, put up in a tight box. Apply to the chaps or cracks two or three times daily, especially at bed time.
BURNS. — Sai.ve for Burns, Fhost-Bites, Cracked Nipples, &c. — Equal parts of turpentine, sweet oil, and beeswax ; melt tlie oil and wax together, and when a little cool, add the turjjeuline, and stir until cold, which keeps them evenly mixed.
Apply by spreading upon thin cloth — linen is the best I used this salve upon one of my own children, only a year and a half old, which had pulled a cup of hot coffee upon itself, beginning on the eye lid and extending down the face, neck and breast, also over the shoulder, and in two olaces across the arm, the skin coming off with the clothes ; id fifteen minutes from the application of the salve, the child was asleep, and it never cried again from the burOj and not a particle of scar left.
It is good for chaps on hands or lips, or for any other sore. If put on burns before blistering has taken place, they will not blister. And if applied to sore or cracked nipples every time after the child nurses, it soon cures them also. For nipples, simply rubbing it on is sufficient. I find it valuable also for pimples, and common healing purposes ^ and I almost regret to add any other preparations for the same purposes, for fear that some will neglect this ; but as there may be cases where some of the following can be made when the above cannot, I give a few others known to be valuable. The first one is from Dr. Downer, of Dixboro, within six miles of our city ; he used it in a ca.se where a boy fell backwards into a tub of hot water, scalding the whole buttock, thighs, and privates, making a bad scald in la bad place, but he succeeded in bringing him successfully through, and from its containing opium, it might be preferable to the first in deep and very extensive burns, but in that case the opium might be added to the first. It is aa follows :
inflamation of Piles, also.
a. f ouLTiCE FOR BuRNS AND FROZEN Plesh. — A. Brouson, of Meadville, Pa., says, from 15 years' experience, that Indian meal poultices covered with young hyson tea, moistened with hot water, and laid over burns or frozen parts, as hot as can be borne, will relieve the pain in 5 minutes, and that blisters, il tney Lave not, will not arise, and that one poultice is usually Bumoient.
4. tJALVE FOR BtJRNS. — Bccswax, Burgundy pitch, white pine pitch, and rosin, of each i lb. ; mutton tallow i lb. ; goose nil 1 gill ; tar i gill, mixed and melted together, and used aa other waives.
This was used successfully on a very bad case, burned all over the face, neck, breast, bowels, &c., soothing and quieting pain, giving rest and sleep directly.
5. Garden and Kitchen Salve for Burns and Frost Bites. — Liveforever and sweet clover leaves, camomile and Bweet elder, the inner bark, a handful of each ; simmer them in fresh butter and mutton tallow, of each i lb. ; when crisped, strain out and add 2 or 3 ozs. of beeswax to form a salve. Spread very thin on thin cloth.
Mrs. Miller, of Macon, Mich., cured a bad case with this, burned by the clothes taking fire, nearly destroying the whole surface. She speaks of it in equal praise for cuts and frost-bites. 8ee the Green Ointment also for Chilblains.
6. The white of an egg beat up, then beat for a long time with » table -spoon of lard, until a little water separates from thero^ I have found good for burns.
lard, is also a good application in burns.
8. Glycerine and tannin, equal weights, rubbed together into an ointment, is very highly recommended for sore or cracked nipples. See Dr. Raymond's statement in connection with the treatment of Piles.
ITCHING FEET FROM FROST BITES,- -To Cure.— Take hydrochloric acid 1 oz. ; rain water 7 ozs. ; wash the feet with it 2 or B time^ daily, or wet the socks with ihe preparation, until relic>«<L
CHILBLAINS,— To CrRE.— Publisijed by Order of thk GovEUNMEKT OF WiRTEMBURG — Mutton tnllow and lard of each % lb. ; melt in an iron vessel and add hydrated oxyde of iron 2 oz. ; stirring continually with an iron spoon, unJl ihe mass 13 of an uniform black color; tlien let it cool^nct add Vtnice-turpentine 2 oz. : and Annrnian bole l oz. ; on ot burgamot 1 dr. ; rub up the bole with a iittle olive oil before putting it in.
troublesome, long continued sores.
FELONS, — Ip Recent, to Clue in Six ITocrs. — ^Venice tuiTjentine 1 oz., and put into it half a tea spoon of water and stir with a rou^h stick until the mass looks like candied hon ey, then spread a good coat on a cloth and wrap around tho finger. If the case is only recent, it will remove the pain in 6 \\o\xf%
2 A poke root poultice on a felon cures by absorption, unless matter is already fonned ; il it is, it soon bnngs it f.o a liead, and tlius saves much pam and suffering,
3 Blue flag and hellebore roots, equal parts, boiled in milk ami water, then soak tlie felon in it for twenty minutes, as hot as can be borne, and bind the roots on the parts for ono hour, has cured many felons, when commenced in time.
kept wet with spirits ol camphor, is also good.
f). Felon Ointment.— Take sweet oil J^ pt., and stew a 3 cent pluij of tobacco in it until the tobacco is crisped; then squeeze it out and add red lead 1 oz., and boil until black; when a little gpol, add pulverized camplior gum 1 oz.
iMi-s Jordan, of Clyde, ©., paid ten dollars for this recipe, aiKi ha.s cured many bad felons, as well as fellows, wilh it. Bcid teilcws because they did not pay l;er. Certainly, this is B rational ase of tobacco.
6. Felon Salve.— A salve made by bumm-g: one tablespoon d( copperas, then pulverizing it and mixing willi the' yolk of an rgg, ia paid to relieve tlio piiin, and cure the fcloB
In twenty-four hours ; then heal with cream two parts, and soft soap one part. Apply the healing salve daily after soaking the part in warm water.
DEAFNESS. — Ip Recent, to Cure — If Not, to Relieve.— Hen's oil 1 gill ; and a single handful of the sweet clover raisec. m gardens ; stew it in the oil until the juice is ah out, strait: i! and bottle for use.
Where deafness is recent, it will be cured by puttlug three or four drops daily into the ear, but if of long standing, much relief will be obtained if continued a sufficient length of time.
2. Much has been said in France about sulphuric ether, first tried by Madam Cleret, of Paris ; and, although she lost her reason by the elation of feeling brought on, no doubt, by the honor given her for the discovery, yet the continued trial of the article does not give the satisfaction which had been hoped for, from its first success.
WARTS AND CORNS.— To Cure in Ten Minutes.— Take a small piece of potash and let it stand in the open air until it slocks, then thicken it to a paste with pulverized gum arable, which prevents it from spreading where it is not wanted.
Pare off the seeds of the wart or the dead skin of the corn, and apply the paste, and let it remain on ten minutes; wash off, and soak the place in sharp vinegar or sweet oil, either of which will neutralize the alkali. Now do not jam nor squeeze out the wart or corn, like " street-corner pedIcrs," but leave them alone, and nature will remove them without danger of taking cold, as would be if a sore is made by pinching them out. Corns are caused by pressure ; in most cases removing the pressure cures the corn. Nine of every ten«corns can be cured by using twice, daily, upon it, any good liniment, and wearing loose shoes or boots. See Good Samaritan.
2. Cure for Corns. — If a cripple will take a lemon, sat off a piece, then nick it so as to let in the toe with the corn, the pulp next the corn — tie this on at night, so that it cannot move — he will find next morning that, with a blunt knife, the corn will come away to a great extent. Two or thiee applications of this will make a " poor cripple" happy for life, — London Field.
itan liniment, which see.
4. Dr. Hauiman's Innocent and Sure Cure for Corns, Warts and Chilblains. — Nitric and muriatic acids, blue vitriol, aud salts of tartar, of each 1 oz. ; add the blue vitriol, pulver izcd, to either of the acids, and in the same way add the sail* of tartar ; when done foaming, add the other acid, and in a few days it will be fit for use.
Directions. — For frosted feet, rub them with a swab oi brush, wet with this solution very lightly, every part that is red and dry ; in a day or two, if not cured, apply again as before. For warta, wet once a week until they disappear, which will be soon, for it is a certain cure in all the above cases, and very cheap. So says the Doctor, of Anderson, Ind.
5. A gentleman in Ohio offers to pay ten dollars a-piece for all corns not cured in three days by binding a bit of cotton batting upon it, and wetting it three times a day with spirits of turpentine.
LINIMENTS.— Good Samaritan— Improved.— Take 98 i)er cent, alcohol 2 qts., and add to it the following articles : Oils of sassafras, hemlock, spirits of turpentine, tinctures of cayenne, catechu, guaicaci, (guac,) and laudanum, of each 1 oz. ; tincture of myrrh 4 ozs. ; oil of origanum 2 ozs. ; oil of wintergreen i oz. ; gum camphor 2 ozs. ; and chloroform H ozs.
I have used the above liniment over five years, and cannot speak too highly of its value; I have cured myself of two severe attacks of rheumatism with it, the first in the knee and the la.st in the shoulder, three years after ; my wife has cured two corns on the toes with it, by wetting them twice daily for a few days; and it is hard to think of anything which it has not cured, such as sprains, brui.ses, cuts, jams, rheumatism, weak back, reducing swellings, curing leg-ache in children from over-playing, for horseflesh, &c., &c. But you will allow me one remark about Uoiuie&ts — they ought in all cases to be put on aud rubbed
in from twenty to thirty minutes, and laying the hand on the part until it barns from its effects, instead of one or two minutes, as is the usual custom ; and if made by the quart, you can use them freely, as the cost is not more than about one-eighth as much as to purchase the two shilling bottles. Wetting flannel with the liniment, and binding on, is a good manner of application. Dr. Hale, of this city, has adopted this liniment for general use ; but for headache and neuralgia, he takes eight ounces of it and adds an ounce of chloroform, and half an ounce of oil of wintergreen, rubbing upon the head, holding to the nostrils, &c. The full preeription will usually cost about two dollars.
2. Liniment for Old Sores.- Alcohol 1 qt. ; aqua ammonia 4 ozs. ; oil of origanum 3 ozs. ; camphor gum 2 ozs. ; opium 3 ozs. ; gum myrrh 2 ozs. ; common salt 2 table-spoons. Mix, and shake occasionally for a week.
This was presented for insertion by H. Loomis, of Edwardsburg, Mich., hoping it might do many others as much good as it had done himself and neighbors. He showed me scars of an old sore on his leg which he had cured with it, after years of suffering; and also called '".p a young man whose father he had cured of a similar sore, years before, which had never broken out again; he used it twice daily. His leg became sore after a protracted fever. I have great contidence in it. He uses it also for cuts, bruises, horse9esh, inflammatory rheumatism, &c., &c.
3. Dr. Ratmoio's Liniment. — Alcohol 1 qt. ; oils of origanum 2 ozs., and wormwood 1 oz. ; with camphor gum 2 ozs. ; spirits of turpentine 2 ozs. ; and tincture of cantharides 1 oz. Mixtd, and used as other liniments.
last is the best liniment in the world.
4. Germ.\k RnEUMATic Fluid. — Oils of hemlock and cedar, of each ^ oz. ; oils of origanum and sassafras, each 1 07. ; aqua ammonia 1 oz. ; capsicum, pulverized, 1 oz. ; ppirits of turpentine and gum camphor, each i oz. ; put all into a quart bottle and fill with 95 per cent, alcohol.
The Germans speak equally in praise of this fluid, as a liniment, as Dr. Raymond does of his, beside.^ they say it is very valuable for cholic in man or horse. DosK. — For cholio, for man, half a tea-spoon ; for a horse, one-half to one ounce U a little warm water, every fifteen minutes, until relieved.
A gentleman purchased a horse for seventy-fire dollara, which had been strained in one of the fetlocks, worth before the strain one hundred and twenty-five dollars. lie cured him with this liniment, and sold him for the original value. lie cured his wife also of neuralgia, with the same, since I have published this recipe. Judge ye of its value.
5. Cook's Electro-Magnetic Liniment. — Best alcohol 1 gal. j oil of amber 8 ozs. ; gum camphor 8 ozs. ; castile soap, shaved fine, 2 ozs. ; beefs gall 4 ozs. ; ammonia 3 F.'s strong, 12 ozs. ; mi.x, and shake occasionally for 12 hours, and it is fit for use.
This will be found a strong and valuable liniment, and also cheap. It may be used iu swellings, strains, <kc., and rubbed upon the throat, breast, and lungs, in asthma, sore throat, &c.
6. Liniment for Spinal Affections. — Take a pt. bottle and put into it oil of origanum, wormwood, spirits of turpentine, and gum camphor, of each 1 oz., and fill it with best alcohol.
Mr. Barr, a gentleman with whom I have been acquainted for some four years, has been troubled with spinal weakness and pains, and he finds great relief from the use of this liniment; and his daughter took it internally for a cough also, with success.
7. GuEAT Londo.n Liniment. — Take chloroform, olive oil, and aqua ammonia, of each, 1 oz. ; acetate of morphia, 10 grs. Mix, and use as other liniments. Very valuable.
This liniment is ready for use in three or four days, and is very highly recommended by E. Burrows, of Matamora Lapeer Co., Mich. He prefers rum, if a good article can be got, in place of the alcohol. This would be excellent Ib cholic, or diarrhea also.
9. Patent Liniment. — In order that those who purchase the patent liniments may know what they are buying, I give a formula, from which over twelve-thousand dollars worth of liniment was sold in two years' time, but one of the partners going out of the firm, and into the livery-business, gave me the plan as follows :
Take whisky 15 gals.; and put into it 2 lbs. of capsicum, pulverized, let staud 10 days and percolate, or draw otl the whisky, free uf tlie sediment ; in the mean time take 1 gal. of spints of tur-
pef tJne and put into it oils of origanum, horse-mint, sassafras, v» beiulijck, (i ozs. each ; add gum camphor 2 lbs. Mix and it ♦ tady to sell, for the purpose of gulling those who suppose •c. i-jbody to be horteat because they are tJienmk^ so.
But that no loss may arise from the space this liniment veyipe occupies here, I will tell you how to make a good linioieut, by using a part of that with the following :
Take of the patent liniment 8 ozs. ; sweet oil and oils of origa QUiJ, sassafras and aqua ammonia, of each 2 ozs., and mix, shakuig well as used, and this mixture will make a splendid horse lini ment, with which you can easily blister, by bandaging the par'-, if desired, and wetting the bandage witlx it.
rhe first would cost less than SI. 00 per gallon, whilst the retail price, two shillings per bottle, makes it over $2.00 per quart. See where your money goes.
10. Lobelia and Cayenne Liniment. — Take a quart bottle ana put into it f oz. of cayenne, pulverized, then put in 2 ozs. of lobel.a herb, and till up the bottle with whisky; in two weeks it is 1 eaily Ibr use, and applicable for cuts, bruises, strains, sprains, iic. ; and it will heal cork cuts in the feet of oxen or horses, wntiout stopping them from labor, and with but Tcry little loieuess, by applying 2 or 3 times daily.
i know a gentleman who had a gash cut in his scalp, four inclies in length, and to the scull in depth, by a falling limb, which by the use of tliis liniment only, as strange as it may appear, it healed without pain or soreness. But some may object to it as a whisky liniment. I admit it to be such, but by knowing how to make it yourselves, you get it for a whisky price, and if it be not found as good as one-half of tlie two-shilling-a-bottle liniments, then you may tell me that I do not know when I have a good thing.
11. Liniment— Said TO BE St. John's. — For 70 doz. bottles, take spirits of turpentine and seueca oils, of each, 4 gals. ; linseed or sweet oil, 2 gals. ; oils of origanum, hemlock, juniper, amber, and lauilanum, of each, 3 qts. ; spirits of ammonia 1 qt. ; tincture of arnica 2 gals. ; camphor gum 1 lb. Put all into a keg and shake well ; when you wish to fill into small bottles, ehake it well and draw into a convenient bottle or pitcher to pour from ; and shake it well every time you till 5 bottles ; and shake the bottle whenever you use the liniment ; thus it might be called Shaking Liniment. No matter what you call it, however, it is a good one.
to prevent the knowledge of its exact composition from being found out by assistants ; it is a ■well known fact, however, that an observing mind can learn much, although not ex pressed in words. Perhaps he will blame me for publishing information gained in that way, but I obtain knowledge foi the benefit of the people ; and as I have called on the Doctor two- different times, to sell my work, but could not succeed, I do not feel under any special obligations to him, and if I did, I go in for the greatest good to the greatest number Were it not so, I should not publish much that is contained in this work, for there are many persons who have and are making fortunes out of single recipes, now published for tha benefit of the world.
Because I could not sell my Recipes to I. L. St. John, a Druggist of TifBn, 0., however, is not saying that I do not sell them to Druggists generally, as I do. In Aurora, 111., I sold to six, and in Pomeroy, 0., to seven, every one in either place, which is not common. They are, however, not only anxious to obtain information generally, but also willing to impart it to others ; and how Mr. St. John should have obtained as good recipes as the ones here attributed to him, without sometime having bought, is a little surprising ; for, as a general rule, those who put out " Patent 31edicines," are not themselves the originators of the recipes ; even Dr. Jayne is reported, I know not how truly, to have picked up the recipe, in an out-house, for his celebrated Alterative. I say, then, am I not justified in publishing these recipes ? Nay, more ! am I not honorable in thus benefiting the {)eopie ? I reat the matter with them j always willing to abide their decision.
Turpentine ar\d seneca oils, of each TJ ozs. ; sweet oil and iincture of arnica, of each 3| ozs. ; oils of origanum, hemlock, juniper, amber, and laudanum, of each IJozs. ; spirits of ammonia i oz. ; and gum camphor i oz. ; which makes u little less than 1 qt, there being 64 qts., besides the gum camphor, in the whole amount.
dnig store, made by the Doctor, which has always given good Hativslaction. And I think any one who tri3s both will be as well pleased with those made from these recipes as with that which is sent out from Tiffin, and make h for onefourth the cost of the other.
By this very simple plan cod liver oil has its peculiar unpleasantness overcome, as well as made far more easy for the stomach to dispose of. But even with this improvement, I do not consider a table-spoon of it equal, for consumption, to a glass of rich, sweet cream, with a tea-spoon of best brandy in it, to be drank at each meal.
CONSUMPTIVES.— Syrup Vert Successful.— Take tamarack bark , without rossing, (the moss may be brushed off,) 1 peck ; spikenard root i lb. ; dandelion root i lb. ; hops 2 ozs. lioil these sufficiently to get the strength, in 2 or 3 gals, of water, strain and boil down to 1 gal. ; when blood warm add 3 lbs. ot noney auvl 3 pts. of best brandy; bottle, and keep in a cool place. Dose — A wine-glass or a little less, as the stomach will bear, 3 or 4 times daily, before meals and at bed time.
Consumption may justly be called the King of diseases, but he has, many times, been obliged to haul down his colors, and give place to health, and consequent happiness, when he came in contact with the above syrup. It does not, however, contain any of the articles usually put into syrups for this disease — this of itself ought to obtain for it a consideration. I have been told, and that by a professional man, that there was not an article in it of any value for consumption. I have acknowledged it does not contain any articles cojnfnunli/ used for that disease ; but allow me to ask if they cure the disease in one case out of a hundred ? The answer is, No. I am now using this on a case within a few miles of the city, who had called one of our Professors. He promised benefit, and did benefit about one week ; subsequently, two other physicians were also called without any lasting benefit. He had not cut his wood for nearly a year, nor done other labor to any extent ; he has now taken our syrup nearly three m»nths; he was weak, spare in flesh, and coughed very much, with cold feet and surface ; he is now stout, fleshy, And scarcely any cough j surface and feet warm. What
more could be asked ? Yet he is very careless, for I calleo on him on a cold, snowy day lately, and he was in the woods, for wood. Do I need better proof of its value? iS'o one would expect sickness of the stomach to arise from its use. from the articles of which it is composed, but the first dose usually makes the person rather sick at the stomach, and sometimes vomits, but don't fear to continue its use. i had rather trust to tamarack-bark tea than three-fourths of th( consumptive syrups of the day. Let every one who is artiict ed with cough, be careful to avoid exposure as much as possible. Remember, with this syrxip^ or disease, as long sa there is life, there is hope.
But it would be deceptive and wicked to hold out to al consumptives the idea that they could be cured — -f'tctt speak like this, although 1 have never seen it in print, nor heard the remark, but my own observation says that nin*'. of every ten htreditari/ consumptives, will, in the end, di"? of the disease, while an equal number of those whose di v ease is brought on by colds being neglected, or from oeglecl of acute inflammations, &c,, may be cured. Then those who know their parents or others in their family to have gone with this disease, need hardly expect a cure, notwithstanding much benefit may be derived from care, with tht above treatment, good diet, and out-of-door exercise, while those whose systems are not tainted from parents may expect a permanent cure.
I shall now throw in a few thoughts of my own,- and from the experience of many others in the profession, whioh I hope may benefit all, needing light on the subject.
•Ftrst, then — Do not go South, to smother and die ; hat go North, for cool, fresh air, hunt, fi.sh, and eat freely cf the roasted game ; cast away care, after having trusted all in Christ, that it may be well, living or dying. Take a healthy, faithful friend with you, to lean upon when needed, in yuui rambles. So shall it be well with many who would otooiwise sink to the consumptive's grave. Have your potatoes with you, and roast them in the embers ; your corn meal also, which you will mix with cold water, having a little «uh in it, and bake on a board before the fire, and then say jou cannot make out a good-flavored meal, and a healthy one also, from your roast venison^ or broiled Jishy with coast pota-
toes and johnny-c^e., I will thon acknowledge that you are iri'ired far gone on tho consumptive's track, and especially if you bave been wandering over hills and through the valley? of our northern country in pursuit of the game of which you »re *bout to partake.
Secondly — Do not leave home after having tried everything else in vain, and just ready to wrap the mantle of the grave around you j then you need all the care of many friends, and a quiet place to die ; but strike out the first thing when you become certain that permanent disease haa fastened upon the lungs ; then you may not only reasonably expect a cure, but be almost certain. Have the means witl) you to avoid getting wet by rains ; but often wash and rab tke whole surfaco, wearing flannel next the skin, and clothe yourself according to the weather and sex ; for there is no reason why females should not pursue about the same course Ihey can dress a la Bloomer, and with their father, husband, brother, or other knoion friend, derive the same bonefit from out-door exercise, like field or forest rambles botanical huntings, geological surveys, or whatever sp<.rts o»" realities may give just the amount of exercise not to fatijuc the invalid.
For females who have familios and cannot, leave them, g^rdeninp- will be the best substitute for the travel, or of all the employments which can be engaged in.
Lastly — Those who are already far down the consumptive track and confined at home, will derive much benefit by u.«<lng, at each meal, half a pint of rich, fresh cream. In all cases it is ahead of Cod-Liver Oil, with none of its disagreeableness. And if it can be borne, a tea, to a table-spoon of the best brandy may be added.
Much is being said, now-a-days, about the necessity of constant inflation of the lungs by long-drawn breaths, hold ing the breath, also, as »ong as possible, when thus fullj inflated; but, for those whose lungs are extensively diseased, it is not only useless, but very dangerous, from the liability to burst blood-vessels in the lungs, causing hemorrhage, if not instant death. In the commencement of the disease. however, or for those in health, the practice is decidedly good.
juice of green hoarhound, each morning for a naonth, if Baid to have worked wonders in relieving the soreness dI" thf lungs, and giving tone to the general health in this disease
3. Chlorate of Potash, for Consumption —A gen tleman of Iowa read a paper about a year ago before the " American Medical Association," upon the subject of Chk> rate of Potash in Consumption, giving the history of a few cases only. For the want of a more extended trial of it, the Association thought best not to publish his paper but referred it back to him, and to the consideration of the. o^hei members for further test.
Amongst those members is Dr. A. B. Palmer, of this city one of the Vice-Presidents of the Association, and I'mt'cv 8or of " Practice, Materia Medica," -fee, in the (Jniversity of Michigan, at Ann Arbor — by the way, a gentleman and a scholar. Having had much experience in practice, he saw fit to give it a trial. He has used it »n about thirty causes, and with a single exception with marked success ; and in that case there was at first much improvement, but the patient was a German who does not unders-aud our language Very well, and from this fact when he fbuud that it caused a heat or burning sensation in the stomach instead of going to the Professor and having the f|uantity J«ssened, he abandoned it altogether. But through Prof. Pa.mer's kindness I have been permitted to refer to other aif^^s where a very marked amelioration has tjiken place. One >f these, a mar ricd lady, although her lungs were full of ^ubercles, with mudli coughing, soreness of the lungs, with sU^irp pains upon full breaths being taken, &c., finds her cough »oose, sorcnesi all gone, and that full breaths can be Uiken without pain, (or stitching, as commonly called,) and fully be^eves that if Bhe could have had this prescription early in tho disease, she would now have been well, yet derives much reb'^f from its use. Another lady has been using it only a few months, and finds that her symptoms are all very much relieved, and she has gained seventeen pounds in flesh.
^(i3 method of giving it is to put about a tea-spoon of the tfbW^rate into a glass of water, which is to be drank a Httle at a time, in from six to twenty-four hours, with other appropriate treatment.
If in any case the chlorate should cause a heat or burning sensaaon at the stomach, lessen the quantity j and unless this does occur, no apprehensions need be felt in using it It improves the general symptoms, lessening the pulse, &c., Tyhilst the Cod-Liver Oil has never done anything more than to benefit merely as food ; and from its very disgusting smell and taste, and the almost impossibility of keeping it upon the stomach, I greatly prefer the fresh sweet cream menti(iiie() above, or the fat meat, as mentioned below.
'I'he hyper-phosphites have been extensively used, but Fruf. Palmer tells me that in Paris and other parts of Europe, where he traveled during the past summer, that not one v,ell authenticated case of cure by them can be produced. Bet he feels much encouraged to hope that th« chlorate will prove itself worthy of great confidence.
The above was written one year ago; and the reports coming in since then, both in America and from Europe, more than confirms the expected benefits and hoped-for advantages from the use of the chlorate in this disease.
4. Remarls on the Use op Fat Meats — Preventive JF Consumption. — There is so much said against the use of fat meats, and e>>pecially pork, as an article of diet, that I cannot better close uiy remarks upon this subject than by giving the opposite opinions of those in high places, corroborated also by my own experience.
Dr. Dixon, of the Scalpel, some time ago, assumed the position that " the use of oils would diminish the victims of consumption nine-tenths, and that that was the whole ^cret of the use of Cod-Liver Oil, to take the place of fat meats."
'* Most individuals who avoid fat meat, also use little but ter or oily gravies, though many compensate for this want in part, at least, by a free use of those articles, and also milk, eggs, and various saccharine substances. But they consti tute an imperfect substitute for fat meat, without which, eooner or later, the body is almost sure to show the effects of deficient calorification."
Now this lady, certainly, was no farmer's wife or she would have observed that the habits of chickens are ten times more filthy than that of the hog, if it be possible; for even the hog's leavings and droppings are carefully overhauled by them, and much of it appropriated to " Ijadies' meat." But their filthiness is no argument in either case; for nature's strainer, (the stomach,) throws off all impurities. Why do so many young Uufies, young cle/y/ynien, and students die of consunjption 1 Simply because chicken or other lean meats, hot biscuit, &c., without exercise, make up the sums of their diet ; when, if they would eat fat meats, with bread not less than one day old, scrub floors, saw wood, or other arm exercise, according to sex, an hour at each end of each day, they might be spared for years — perhaps to long lives of usefulness, to their families, congregations, or the world.
5. So far as pork is concerned as food, the following rule may be safely followed : If it agrees with the stomach, which is known by its digesting without " Kising.s," as it is called, its use may be continued, but if it rises, lessen the quantity, and if it still rises, abandon its use altogether; but 1 digests better with me than mutton, or chicken, and 1 have been trying them for nearly Ji/t^ years. The same rule is good for all articles of food. As to exercise^ for men who are not regular laborers, wood-sawing is the bast, next, horseba^^iding, then walking; for women, hobing in the garden or field, next sweeping, dusting, &o., iimt^ horseback riding, walking, &o.
6. But I have recently seen a piece going the rounds of t^'S papers as the best cure for consumption in the world, WQich contains so much good sense that I will close my remarks on the subject by giving it a quotation, and let every one judge for themselves, which to try, if they see fit to give either a ti'ial. It is represented as coming from an exchanye only, but from its style of. remark, I think it must hav« started from Hall's Journal of Health :
" Eat all that the appetite requires of the most nourishing food, such as fresh beef, lamb, oysters, raw eggs, fruit, vegetables, and 3 times a day take a glass of egg-nog, made as rich as the patient can bear. Avoid all other alcoholic drinks. Bathe tv/ice ft week in water made agreably warm, and in a warm room ; after bathing rub the body and limbs witli sweet cream or sweet oil. Exercise daily in the open air ; walking is the best. Stand erect, exercise the arms and lungs freely, keep the mind cheerful ; take freely of the best cough syrup, and consumption will be a stranger to your household.
" For making the best cough syrup, take 1 oz. of thoroughwort ; 1 oz. of slippery elm ; 1 oz. of stick licorice, and 1 oz. of flax seotl ; simmer together in 1 qt. of water until the strength is entirely extracted. Strain carefully, add 1 pt. of best moUisees and i lb. of loaf sugar ; simmer them all well together, and when cold bottle tight. This is the cheapest, best, and safest medicine now or ever in use."
" A few doses of one table-spoon at a time will alleviate the most distressing cough of the lungs, soothes and allays irritation, and if continued, subdues any tendency to cousumptioQ ; breaks up entirely the whooping cough, and no better remedy can be found for croup, asthma, bronchitis, and all affections of the lungs and throat. Thousands of precious lives may be saved every year by this cheap and simple remedy, as well as thousands of dollars which would otherwise be spent in the purchase of nostrums which are both useless and dangerous." — Exchange. For egg-nog eee " Stimulant in Low Fevers."
OINTMENTS.— For Old Sores.— Red precipitate i oz ; su gar of lead i oz. ; burnt alum 1 oz. ; white vitriol ^ oz, or a littl less ; all to be very finely pulverized ; have mutton tallow made warm ^ lb. ; stir all in, and stir until cool.
Mr. Brownell, of Dowagiac, Mich., thinks there is no ointment equal to this for fever or any other old sores, from actual trial, as much so aa Mr. Loomis does of his Liniment Wo. 2.
126 DB. CHASr. 8 RECIPES.
2. JuDKiNs' Ointment. — This ointment has been long celebrated through Ohio and the Eastern States. It waa invented and put up by an old Doctor of that name, whose family took to the profession of medicine as naturally as ducks to water. I obtained it of one of the sons, who is practicing at Malaga, Ohio, from whom I also obtained Landolfi's and his own method of curing cancer, (see those recipes,) and he always uses this ointment to heal cancers and all other sores :
Linseed-oil 1 pt. ; sweet oil 1 oz. ; and boil them in a kettle on coals for nearly 4 hours, as warm as you can ; then have pulverized and mixed, borax i oz. ; red lead 4 ozs., and sugar of kad li ozs. ; remove the kettle from the fire and thicken in the p/vwder ; continue the stirring until cooled to blood heat, then stir in 1 oz. of spirits of turpeutme; and now take out a little, letting it iret cold, and if not then sufficiently thick to spread upon thin, Boft linen, as a salve, you will boH again until this poiat i« reached.
He says, and I have no doubt of it, that it is good for all kinds of wounds, bruises, sores, burns, white swellings, rheumatisms, ulcers, sore breasts, and even where there are
8. 8isson's Ointment. — Best brandy i pt. ; turpentine 1 gill ; camphor eum 1 oz. ; beefs gall i pt. ; (beefs gall bottled with i alcohol will keep nice for future use,) neats-foot oil 1 pt. Mix.
This ointment, or properly liniment, is probably not equaled for reducing swellings which arise from bad bruises, or Bwellings of long standing ; rub it in for quite a length of time, then wet a flannel in it and wrap around the parts.
4. Grtjen Ointment. — White pine turpentine and lard i lb each ; honey and bees- wax i lb. each ; melt all together and stii in i oz. of very finely pulverized verdigris.
In deep wounds and old sores this works admirably, it keeps out proud flesh and heals beyond all calculation, keeping up a healthy discharge. It was used on a horse, which had run upon a fence stake, the stake entering under the ehoulder-blade and penetrating eighteen inches alongside of the ribs ; the ointment was introduced by stiffening linen cloth with warm beeswax, and rolling it up into what is called a teut, then smearing the ointment upon the tent, and pushing it to the bottom of the wound, which kept the out-
eide from healing until it healed from the bottom, and thus saved the horse, which everybody said must die ; and ol course everybody always knows. The man owning the horse was thrown from his buggy whilst the horse was running^ and had a leg broken ; the horse was well before the man. Hiram Sisson, an old farrier and farmer, of Crown Point Essex Co., N. Y., has used this and the one bearing his Dame, No. 3, several years, and speaks of them in the highest terms. Mr. Wykoff,a few miles north of this city, has used this green ointment for several years, curing a deep cut in the thigh of a friend in a few days with it, which induced him to pay ten dollars to an English lady for the recipe ; since then he cured a bad case of chilblains, with it, upon a German boy who had not worn boot or shoe for three years, on their account. I have now known it for two years, curing cuts on horses' feet, from stepping over corn stubble in spring ploughing, by only a few applications. It is worth more than the cost of this book to any family who has not got it.
ana the world cannot beat it for general use.
5. Grekn Ointment — Honey and bees-wax, each i lb. ; spirits of turpentine 1 oz. ; wintergreen oil and laudanum, each 2 ozs. ; verdigris, finch; pulverized, J oz. ; lard H lbs ; mix by a stove fire, iu a copper kettle, heating slowly.
I have given this green ointment, varying somewhat from the first, obtained of a gentleman at Jamestown, N. Y., who was selling it in large quantities, as he uses the spirits of turpentine instead of the white pine, for that frequently is hard to get, and by some this will be preferred, for the flesh of a few persons will inflame under the free use of verdigris, and it will be seen that this last recipe has not near as much of it in as the first.
6. Dk. Kittredge's Celebrated Ointment, — For " Pimptjed-Face," " Prairie-Itch, &c. — Take a*pint bottle and put into it nitric acid 1 oz. ; quicksilver 1 oz., and let stand until the silver is cut ; then melt lard i lb. iu an earthen bowl and mix all together, and atir with a wooden spatula until cold.
Old Dr. Kittrcdge is an Allopathic Physician, but his ointment has been known, over the whole State, as death to the " Michigan or Prairie Itch," and the Doctor recommends
it for Cancerous, Scrofulous, arid Syphilitic Ulcers, alao Salt. rheum, Ring-worms, " Pimpled Face," Chronic Inflammation of the eyelids, &c. Application. — For cufcancuus eruptions, scratch ofi" the scab, warm the cerate, rub in thoroutchly once a day ; for running ulcers, spread a thin plaster, and not change oftener than once in thirty-six or forty-eight hours.
7. Mead's Salt-Riteum OrNTMHNT. — Aquafortis 1 oz. ; quickail ver 1 oz. ; good hard soap dissolved so as to mix readily 1 oz. ; prepared chalk 1 oz., mixed with 1 lb of lard ; incorporate tlie above by putting the aquafortis and quicksilver into an earthen vessel, and when done effervescing, mix with the other ingredients, putting the chalk in last, and add a little spirits of tuipentine, Sciy ^ a table-spoon.
Mr. Mead is a resident of this city, advanced in age, over ninety years, and great confidence may be placed in this recipe. He sent it for insertion in the seventh edition of this work, and iminy have tried it with satisfaction. He first proved it on himself, after sufiering with Salt-rheum for ten years ; at first it came back after two years ; he then cured it again, and now has been free from it about fourteen years. His only object in pre-scnting me the recipe was to do good to his fellow-creatures. Some physicians think that if nitrio acid one ounce and three drachms, was put upon the quicksilver, and cut or dissolved by gentle heat, that it would bo a better way to prepare it; but I never wish to change when an article works as well as this does.
First, wash the part with Castile soap and water, dry with a soft clotli, then wet the parts erupted with the tincture of iodiuB. and after this gets dry, anoint with citron ointment. When the eruption exists about parts not covered with clothing, use the following wash alternately with the tincture : Corrosive sublimate 1 dr. ; sugar of lead 3 ozs. ; white vitriol 2 scruples ; Balammoni.ac 3 drs. ; common salt 2 drs. ; soft water 1 pt. ; mix.
He had a case — a young gentleman who was engaged to be married, but the lady would not marry him until cured from the fact that a sore of a leprous or obstinate character surrounded his head where the hat came in contact with it. But patience and nine months perseverance removed the scab frorm bis crown, and crowned him with a help-meet
Let me here say, that ia any disease of long standing, Ct2>e some of the alterative medicines to cleanse the blood, while using the outward applications. The " Cathartic Alterative" is especially adapted to these skin diseases, and should be continued some time, even if you are not anxious to get married. The Citron Ointment is kept by nearly all Druggists.
10. Itch Ointment. — Unsalted butter 1 lb. ; Burgundy pitch 2 oz. ; apirits of turpentine 3 ozs. ; red-precipitate, pulverized, 1 i ozs. ; melt the pitch and add the butter, stirring well together ; then remove from the fire, and when a little cool add the spirits of turpt ntinc, and lastly the precipitate, and stir until cold.
think it the cause.
11. Magnetic Ointment. — Said to be Trask's. — Lard, rai Bins, cut in pieces, and fine-cut tobacco, equal weights; siramei well together, then strain and press out all from the dregs. ■
The above is an excellent ointment, and looks like its namesake, and its action is really magnetic. Mix this in equal parts with the first Green Ointment No. 4, and it will make a good application in Piles, Salt-Rheum, and all cutaneous or skin diseases, as well as cuts, bruises, &c. If used m Salt-Kheum, some of the alterative remedies must bo ta&^en at the same time, and long continued.
12. Stramonium OiNTiMENT. — The probaJ)ility is, that for general use, no ointment will be found superior to this, yi hen properly made. It is kept by most Druggists, but it is not half as good, generally, as if made by the following directions. I give large proportions, from the fact that it will be used ia large quantities. Stramonium is known by the namw of " Jimpson," « Stink- Weed," " Thorn-Apple," &c., from its thorny burr.
Vifk about a bushel of the leaves, while yet green, having a suitable u-on kettle placed over a slow fire ; put m a few of the Vtuvcs and mash them as you keep adding until you get
them all mashed into a pulpy mass, then put in lard 5 lb»., and stew to a crisp ; then strain and box for use. Those who live in towns and prefer to make it with less trouble, will purchase 1 dr. of the soft extract, kept by druggists, rubbing it with a little water until it is of such a consistence as to allow it to be rubbed into an ointment with lard 1 oz. This will be better than the sale ointment, but not as good as the " Home Made," above.
It is anodyne, (relieves pain,) in burns, scalds, old irritable ulcers, skin diseases, painful hemorrhoids, (Piles,) and is discutient, (driving away swellings.) and very strengthening to broken limbs, i. e., after the bones are healed to rub over the limb freely, and thoroughly ; it reduces the swelling and gives tone to the muscles, tendons, &c.
We have recently known two cases of fracture, one a compound fracture of the ancle, the other of the wrist, both in persons well advanced in life ; in both cases strength returned very slow, but with double speed by the free application of this ointment ; and in the first case it undoubtedly prevented mortification. It is valuable, also, in painful oi swelled rheumatism. Or, perhaps what would be preferable, n such cases, is a tincture made of the seeds irom the horny-burr, two ounces, to alcohol and water, of each, a half-pint. If it is not found ahead of fhe " Tincture of Arnica," I will give you my head for a " Foot-Ball." In applying it, wet cloths or brown paper, and bind upon the parts, keeping them well wet. To make this tincture, see •* Tinctures."
Good sized live toads, 4 in number; put into boiling WHter and cook very soft ; tlien take them out and boil the water down to i pt., and add fresh churned, unsalted butter 1 lb. and simmer together ; at the last add tincture of arnica 2 ozs.
This was obtained from an old Physician, who thought more of it than of any other prescription in his possession. Some persons might think it hard on toads, but you coaki not kill them quicker in any other way.
JAUNDICE.— Dr. Pkabodt's Cure,— In its Worst FoRMa. — Red iodide of mercury 7 gra. ; iodide of potassium 9 grs. ; aqua dis. (distilled water,) 1 oz. ; mix. Commence by giving 6 drops 3 or 4 times a day, increasing 1 drop a day until 12 or 15 drops are given at a dose- Give in a little water inusBdiatfii^
•tier meals. If it causes a griping sensation in the bowels, and Rillness in the head when you get up to 12 or 15 drops, go back to 6 drops, an:! up again as before.
above to be entirely successful.
i am aware that many persons will not use any preparation containing mercury in any of its forms, while there are many others who would use them for that very reason ; my object is to benefit all, without strengthening the prejudice* ©f ojiy ; for this reason I give you the following :
2. Drink for Jatjkdice. — Tie up soot and saffron, equal parts, in a cloth to the size of half of a hen's egg, let it lie in a gla*i3 of water over night; in the morning put the yolk of an «gg, beaten, into this water, and drink it. Do this 3 mornings, »kipping 3, until 9 doses have been taken.
remedies.
PILES. — Successful Remedies. — Internal Remedt. — Cream of tartar, jalap pulverized, senna, and flowers of sulphur 1 oz. each ; nitrate of potash, (saltpetre;) i oz. ; golden seal 1 oz. ; thoroughly pulverize all together, in a mortar, and give a teaBpoon three times every day, or the dose may be varied to suit the condition of the patient, taking more or less to suit circumBtauces, keeping the bowels in a solvent state.
External Application. — Inner bark of the white oak tree, boil and strain, and boil again until you obtain i pt. of the extract, very thick ; then add i pt. of the oil of the oldest and Btrongest bacon you can procure ; simmer together until a union takes place when cold. Then apply by the finger up the rectum every night until well. Be very strict to abstain from strong and stimulating diet. The above is a sure cure for blind or bleeding piles, in all cases, sooner or later.
Dr. Hariman, of Andersontown, Ind., has been very sueeessful with this plan of treating Piles ; and since I obtained the plan, now two years, I have had one opportunity of proving its efficiency, upon a gentleman who had been laid np for days, and sometimes weeks, with the complaint ; by a few applications of the external remedy he has been enabled to keep directly along with his labor.
2. Pile Cerate.— Carbonate of lead i oz. ; sulphate of morphia 15 grs. ; stramonium ointment 1 oz. ; olive oil 20 drop*, Mix, aa<* apply 3 times a day, or as occasion and pain may re-
This cerate has been highly celebrated as a remedy ia Piles. It will relieve the pain most assuredly. Piles have been cured with lamp oil applied to the parts two or three times a day. Even tallow, or any simple ointment, is good for dry Piles, that is, for pain in those parts, coming on :?ften in the dead of night, without apparent cause.
3. For External Piles, — The following Is very highlj spoken of: Take oyster shells, wash and burn them, thea Snely pulverize and rub up with fresh lard ; annoint with this, and take internally sulphur one ounce, mixed wiih three ounces of pulverized rosin ; take night and morning what will lay on a five cent piece. Take every day for the first week, then eyery three or four days, until well, continuing the ointment.
4. Mrs. Moreiiead,— Of Danville, Ind., cured herself of Piles by simply sitting in a hip-bath of warm water, every time the pains would come on, after stools, or any other time, remaining in the bath until the pains left her. Her husband cured himself by sitting in cold water, and using upon the parts an ointment made by stewing celandine in fresh lard. I give these various plans, so that if one fails, a remedy may certainly be found amongst the many given.
5. G, P. Rogers, of Ironton, 0., has known cases cured oy using the following ointment : Powdered opium and powdered rosin, one ounce each, mixed with one ounce of tallow, md anoint as required.
6. Dr. D. W. Raymond, of Conneaut, O., says : Equal weights of glycerine and tannin will cure Piles, by anointing with it, and that very speedily ; also cures sore or cracked nipples in twenty-four hours, and is remarkably good for any excoriation, or sore, of the skin. I know that simple tallow introduced into the rectum is exceedingly beneficial in Piles, which satisfies me that any preparation containing oil or any kind of grease, is good.
7. I have found in the scrap of an old newspaper, the following, and it is so e^isily tried, and speaks with so much certainty, and is so simple, that I give it an insertion :
case may require.
It has been used with complete success in old and inveterate cases where individuals had spent scores of dollars in medical advice. It is equally useful as a preventive. It will injure none, and only requires a trial."
8. Paschal Mason, living near this city, cured a Southern lady, visiting in the neighborhood, who was confined to the bed with them, by making a strong tea of the wild Bwamp-currant root, drinking occasionally for a few days only.
many cases.
ANODYNES— Hoffman's Anodyne, or Golden Tincture. — Sulphuric ether 2 ozs. ; alcohol 4 ozs. ; and etherial oil f dr. ; mix. Dose — From half to two tea-spoons, (i dr. to 2 drs.) according to the urgency or pain lor which it is given.
It is given in a little sweetened water, and much preferred by ihe Germans to laudanum, especially where laudanum causes sickness of the stomach. • It makes an excellent local application in neuralgia and other painful affections, being •second cousin to the Magnetic Tooth Cordial and Paralytic Liniment.
2. Laudanum. — Best Turkey opium 1 oz., slice, and pour upon it boiling water 1 gill, and work it in a bowl or mortar until it ib dissolved ; then pour it into the bottle, and with alcohol ol 76 per cent proofs pt., rinse the dish, adding the alcohol to the preparation, shaking well, and in 24 hours it will be ready for use. Dose — From 10 to 30 drops for adults, according to the strength of the patient, or severity of the pain.
Thirty drops of this laudanum will be equal to one grain of opium. And this is a much better way to prepare it thaa putting the opium into alcohol, or any other spirits alone, for in that case much of the opium does not dissolve. Sea the remarks occuring al'ter Godfrey's Cordial.
3. Paregoric. — Best opium ^ dr., dissolve it in about 2 tatlespoons of boiling water ; then add benzoic acid ^ dr. ; oil of anise i a fluid dr. ; clanfled honey 1 oz. ; camphor gum 1 scruple ; alcohol, 76 per cent, 11 fluid ozs. ; jdistilled water. 4^ fluid oz.s. ; macerate, (keep warm,) for two weeks. Doss — For children, 5 to 20 drops, adults, 1 to 3 tea-spoona.
Used as an anodyne and antispasmodic, allays <»ough, relieves nausea and slight pains in the stomach a»d boweb, checks diarrhea, and procures sleep. Used prinmpallj for children. See the remarks after No. 5, below.
4. Bateman's Pectoral Duops. — Opium in powd w, catechn in i)owcler, camphor gum, red saunders, rasped, of fwrh + oz. ; oil of anise 1 dr.; dilute alcohol, (alc(ihol of 76 per c*ut, and water in equal proportions,) 1 gal. Keep warm for 2 Weeks.
below.
5. Godfrey's Cordial. — Dissolve pure carbonate of potassH 1 oz. in water 5 qts., and add nice golden syrup or best molasses 8 qts., and heat until they begin to simmer ; take off the scum, and add laudanum 9 ozs., and oil of sassafras 1 dr. Mix well. Used similar to the two last.
Remarks. — It is a well known fact tkat much injury ia done to children by the use of anodynes, such as the above, and " Mrs. Winslow's Soothing Syrup," which is now taking the place, to a great extent, in towns of the foregoing, for I noticed a short time ago eighty-seven empty bottles with Mrs. Winslow's label upoli them, sitting on a counter of one of our drug stores, which led me to ask if they put up her syrup. The answer was no, a laOy in this city has fed that much to one child within the past eiyhteen months.
The question might be asked, why do you tell people how to make any of these anodynes ? Because they are good in proper cases, when properly used, and to give a place for these remarks ; for those wiio are evil disposed will find a way to accomplish their designs, whilst the well disposed will, or can, act only from knowledge, and if they do not know the evils arising from the constant use of anodynes on children, are as liable to do evil as the evil disposed.
Then let it be remembered that the constant use of opium in any of its preparations on children, or adults, disturbs th« nervous system, and establishes a nervous necessity for i\M continuation. Then use them only in severe pain, or ex. treme nervousness, laying them by again as soon as possible under the circumstances of the case. Of course we do not give a receipe for the Soothing Syrup spoken of, as its exact composition has not yet come out to the public ; but that \tf
especially for children.
RHEUMATISM' S — Infl amm atoby Rhettmatism— Bili. "WKiGnx's, AND OTHEU CuRES. — SulphuT and salt-petrc, of each 1 oz. ; gum guaiac i oz. ; colchicum root, or seed, and nutmegs, of each i oz. ; all to be pulverized and mixed with simple syrup or molasses 2 oz. Dose — One tea-spoon every 3 hours until it moves the bowels rather fi-eely ; then 3 or 4 times daily until cured.
Mr. "Wright, of the Niagara Hotel, Toledo, 0., has several times proved this to be an excellent medicine, and since I obtained it I found a man at Marshall, Mich., one Saturday evening, with his feet and legs so swollen with this disease, that he could but just crawl with two crutches. I filled this prescription and gave him a tea-spoon of it every two hours, until it moved his bowels, then every four hours, and on Monday noon he could walk quite comfortably without cana or crutch, the medicine costing only twenty cents.
valuable :
Colchicum seed, and black cohosh root, of each i oz., the root to be bruised ; best rye whisky 1 pt. ; put together and let stand 3 or 4 days. Dose — From one tea-spoon to a table-spoon 3 times daily, before meals.
The action will be to loosen the bowels, or cause a little sickness at the stomach ; and the dose may be modified not to cause too great an efiect upon the patient either way, but increasing the dose if necessary until one of these specific actions is felt, and lessening it if the action is too great in any case.
3. Rheumatic Linimekt. — Olive oil, spirits of camphor, and chloroform, of each 3 ozs. ; sassafras oil 1 tea-spoon. First add the oil of sassafras to the olive oil, then the spirits of camphor, and shake well before putting in the chloroform, shaking when used, keeping it corked, as the chloroform evaporates very fast if left open. Apply 3 or 4 times daily, rubbing it well, and always towards the body.
1 had a brother-in-law cured of a very bad case of inflammatory, or swelling rheumatism, by the use of this liniment — •ooomplished in about four days, without other treatment
He paid five dollars for the recipe after the core. But 1 would recommend the use of this in connection with " Bill Wright's Cure," above, feeling perfectly assured that no attack will stand before the internal and external combination.
4. J. B. HiTCHCox, Ypsilanti, Mich., uses spirits of ti-.rpentine 1 pt. ; tar 2 tea-spoons ; oil ot vitriol 1 tea-spoou, mixing in a mug ; then sets them on fire, letting it biun 15 minutes, and bottle for use.
He bathes the parts freely twice daily with this preparation, then binds on the mashed tory-weed, as mentioned under the head of " lleducing Swellings," and gives a little spirits of turpentine internally.
6. Alvah Raymond — Takes Rum 1 pt. ; neats-foot oil i pt.. or if the joint is stiff, skunk's oil instead of the Dther ; spirits o' turpentine 1 gill, and simmers them together, and bottle for use, rubbing it in thoroughly 3 times daily.
He also directs to soak the feet in hot water, scraping the bottoms of the feet with an old knife; then he has poke root roasted and mashed, mixing with it tar and sulphur t<7 form drafts for the feet. With this method of treatment he assures me he has been very successful for 30 years. And it bears so strong a resemblance to Dr. Kittredge's preparation, next following, for stiffened joints in rheumatism, that it gives me double confidence in them both.
6. Dr. Kittuedgr's Remedy for Rheumatism and Stiff Joints. — Strong camphor spirits 1 pt. ; neats-foot, coon, bear, or skunk's oil 1 pt. ; spirits of turpentine i pt. Shake the bottle when used, and apply 3 times daily, by pouring on a little at a time and rubbing in all you can for 20 to 30 minutes.
The old Doctor recommends this as a sure cure for chronic rheumatism, sprains, stiff-joints where they have not formed an anchylosis, that is, if the bones have not actually grown together ; and as remarked in connection with his ointment, No. 6, he has been a very celebrated Physician for many years ; but like many other men with superior minds, oh ! Low fallen. Rum, and its advocates, have got a most fear ful account to balance.
7- French and Other Remedies for Chronic Rheumatism.— Dr. Bonnet, of Graulbet, France, states in a letter to the Abeille Medicale, that he " has been long ic the habit of rrescribing :
" The essential oH of turpentine for frictions against rheumatism. And that he has used it himself with perfect success, having almost instantaneously got rid of rheumatic pains in both knees and in the left shoulder."
He was led to make the prescription from having used the oH of turpentine to wash coal-tar and other sticking mixtures from his hands. After having washed his hands in scip and water, and drying them, a pricking sensation like an electric spark upon the knuckles from a machine, lasting about two hours, was always experienced, and it is to thia exciting action that he attributes its efficacy. It may be used twice or thrice daily.
8. Chronic rheumatism has been cured in twcnty-foui hours, after two years' suffering, by using alcohol, spirits of turpentine, sweet spirits of nitre, and oil of juniper, equal parts of each ; mix ; rub well into the parts, and take ten drops at bed time in water.
9. BiTTEKS FOR Chronic Kmeumatism. — Prickly-ash berries, spikenard root, yellow poplar and dog-wood barks, of each \ lb. ; all pulverized and put into a gallon jug, and fill it up with brandy. Dose — A wine-glass of it is to be taken 3 times daily before meals.
amount, of a very bad case of this disease of long standing.
10. David Mowry, of Greenville, Ohio, says yellow poplar, dog-wood, prickly-ash, wild cherry and white-ash barks of the trees, equal quantities of each, a good large handful, boiled in 2 gals, of water, to 1, and add 1 gal. of good old rye, will, if taken freely 3 times daily, cure the worst inflammatory rheumatiiua in the world.
There is no question But what both of these preparations, and the next also, are good, if made sufficiently strong with the barks. But I should consider them much more applicable in chronic cases, or rheumatism of long standing ; and in these cases very applicable indeed, and I am well satisfied that no one will take them for the spirits. *
11. CuKONic Rheumatism, has been cured by taking the bark of a bearing crab-apple tree, and putting a sufficient amount of it into whisky to make it very strong, then taking a wine-glass three times daily, until a gallon was used.
flwamp hellebore i oz. ; prickly ash, bark or berries 1 oz. ; pok« root, cut fine, 1 oz. ; rye whisky 1 qt. ; let stand a few days before using. Dose — One tea-spoon every 3 or 4 hours increasing the dose to 2 or 3 tea-spoons, as the stomach wUl bear.
Soak the feet well and go to bed, covering up warm, and taking the '' Sweating Drops" between each dose, as there directed, for three or four hours, and repeat the sweating eyery day until the disease surrenders to the treatment. If at any time tlie heiid feels too full, or the stomach sicken* too much, drop down to the first dose of a tea-spoon, or evea less, if necessary.
this disease.
13. I know an old physician who assures mo that he hmt cured cases where all other remedies failed, with saltpetre, beginning with twenty grains, and doubling the dose every three or four hours, until it reached half an ounce, in a very robust and plethoric patient ; but this dose would be too large to venture upon by persons not of a plethoric habit. But as it is mostly prescribed, by putting a table-spoon to a pint of whisky, then a tea-spoon for a dose ; you might as well expect to dip the Atlantic into the Pacific with a teaspoon, as to cure rheumatism in that slow way. It may be token in quantities from half an ounce to an ounce and a half in the twenty-four hours, being largely diluted with water. If pain should come on in the stomach, under its use, stop it at once, and give large quantities of mucilaginous drinks, such as slippery-elm water, gum-arabic water, ftaxBced tea, &c.
14. Nkw Remedy. — Kerosene oil 3 ozs. ; skunk's oil 1 oa. ; mix, and shake when applied. Put it on quite freely, and heat it in by the stove, or by means of a hot shovel.
A firm of grocers, Slawson & Geer, of this city, have been using this mixture during the past winter upon their own persons, and have recommended to many others amongst them, one of the Clergymen, and also the President of the University, and so far as they know, it has proved very sue<!e?sful, relieving the pain directly.
The smell of the kerosene is not very pleasant, but if a pair of ankles and feet, badly swollen, so much so that you could not walk on thera for months, could be cured in two or three weeks, as it was in this case, it might be well to put up with its disagreeable smell. Rub and heat it in thor* oughly twice daily.
ASTHMA — Reatedies. — Elecampane, angelica, comfrey, and spikenard roots, with lioarhound tops, of each 1 oz. ; bruise and cteep in honey 1 pt. Dose — A table-spoon, taken hot every few minutes, until relief is obtained, then several times daily until a cure is effected.
It cured a young lady, near the " Falls of the Ohio," whom the doctors said it was wicked to disturb ; " let her die in peace," was their advice to the parents. An old lady, instead, let her live in peace. It will be found very excellent in any cough ; even low consumptives will find great relief from its use.
2. Dr. J. K. Finley, of Pittsburg, cured a lady with whom I afterwards became acquainted, and from the completeness of the cure, I was induced to write to the doctor and obtain the prescription. It is as follows :
I have very great confidence in this prescription.
3. A lady at Yellow Springs, O., tells me that she cured herself of Asthma, by using, for her common drink, a tea made of the leaves of common chestnut, which had fallen from the tree in antra n ; sweeten well, and continue its use for 2 or 3 months.
She used it for a month at first, and it returned,, when she continued its use for two months ; and ten years have elapsed without its return. It is certainly safe as well as pimple, and of easy trial.
taking 5 gr. doses, 3 times daily. Take i oz. and put U into • vial and add 32 tea-spoons of water — then 1 tea-spoon of it wUl contain the 5 grs., which put into i gill more ot water, and dnuk before meals.
COMPOSITION POWDER— Thompsons.— " Bayberry bark 2 lbs. ; hemlock bark 1 lb. ; ginger root 1 lb. ; cayenne peppci 2 ozs. ; cloves 2 ozs. ; all finely pulverized and well mixed. Dose — One-half of a tea-spoon of it, and a spoon of sugar ; p^al them into a tea-cup and pour it half full of boiling water ; l?t il stand a few minutes and fill the cup with milk, and drink freely If no milk is to be obtained, fill up the cup with hot water.
"This, in the first stages and less violent attacks of diseas* is a valuable medicine, and may be safely employed in ali cases. It is good in relax, pain in the stomacli and bowels, and to remove all obstructions caused by cold. A few doses, the patient being in bed with a steaming stone at the feet, or having soaked the feet fifteen or twenty minutes in hot water, drinking freely of the tea at the same time, will cure a bad cold, and often throw off disease in its first stages." I use it, taking, or giving, lobelia emetics as mentioned under the head of " Eclectic Emetics." I use it also, as a :
"2. Dyspkpttc Tea. — Where an attack has been broiiglit on by over-indulgence at an extra rich meal, you will find iiinnediate and generally perfect relief by having a cup of this tea made," atid drinking about one-half of it fifteen minutes before meals, and the balance just as you sit down to the meal, not taking any other fluid at all until after digestion i.s over, following up the same plan for a few days or weeks, as may be necessary. It stimulates the stomach to action, causing dijestion and absorption, preventing also the accumulation of gas, which is the cause of eructations of wind from the stomach, commonly called belching, and gives tone to the whole system.
A cup of this tea taken when going out into extreme cold, will be found a better warmer than the whisky or any other arient spirit, which so many resort to upon such occasions; and, what is best of all, it will be found :
3. A Perfect Cure for Drunkenness. — hH those who are accustomed to the excessive use of ardent, spirits, and who wish to step the practice, I say, let such have a oup of this tea made, as abp^^i directed, and drink a part of
it immediately ou rising in the morning, and th« balanc* just before meal time, keeping entirely away from tha places of temptation, they will find a warm, healthy glow spreading from the stomach over the whole system, with a desire for food, instead of " rot-gut/' Follow this up faitkfully two or three times daily, or whenever the craving begins, for the accustomed stimulus, for a few days or weeks, if necessary, and it will be found that the cayenne, which is the purest stimulant in the whole Materia Medica, with its assistant, the bayberry, which stimulate without an after prostration, have gradually supplied and satisfied the previous false appetite or cravings of the stomach ; whilst the combination has toned up the stomach together with the whole system, and again you find yourself a man. But remember, oh, remember ! your only safety is i?i keeping entirely away from places where intoxicating spirits are kept or sold !
A hiu-ned child will not play with fire. I would to God that a burned man was equally wise. For not one in a thoivsand can resist the solicitation of enemies, (called friends,) to take a glass, just one, and that one glass acts like fresh coals upon extinguisJied brands, and the fire goes ahead again with a hundred fold more energy than if thrown upon wood which had never been charred ; hence, the propriety of the sentence " plucked as a brand from the everlasting burnings,"— for if re-kindled there is but little prospect of another extinguishment of the raging fire. Dr. Thompson, notwithstanding all that has been said against him, has done more good than any other medical man that ever lived ; for he set the people to studying for themselves.
STIMXTLAJ^T— In Low Fevers, and After Uteroje Hemorrhages.— MiSTURA Spiritus vtni Gallici.— Best brandy, and cinnamon water, of each 4 fluid ozs,; the yolks of 2 eggs, well beaten ; loaf sugar ^ oz. ; oil of cinnamon 2 drops ; mixDofiK — From i to 1 (fluid) oz. ; as often as required. This makes X)th eat and drink. Of course, any other flavoring oils can b« used, if preferred, in place of the cmnamon.
This mixture is an imitation of the well-known compound termed " egg-flip." It is an exceedingly valuable stimulant and restorative, and is employed in the latter skiges of low Feverfl, and in extreme exhaustioD from atorine homorrhagea
treatment of consumption, No. 6.
ALTERATIVES.— Syrup or Blood Purifier.— Honduras sarsaparilla 12 ozs. ; guaiacum shavings 6 ozs. ; ■winter green leaf 4 ozs. ; sassafras-root bark 4 ozs. ; elder flowers 4 ozs. ; yelloTV dfjck 3 ozs. ; burdock-root 4 ozs. ; dandelion-root 6 ozs. ; bitterBweet-root 2 ozs. ; all bruised. Place these ingredients in a suitable vessel and add alcohol 1 pt., with water sufficient to cover handsomely, set them in a moderately warm place for 3 or 4 days, pour off 1 pt. of the tincture and set it aside until you add water to the ingredients and boil to obtain the strength, pour ofiF and add more water and l)oil again, then boil the two waters down to 1 qt. ; strain, and add tlie liquor first poured off, and add 2^ lbs. crushed or coffee sugar, and simmer to form a syrup ; when cool, bottle and seal up for use, Dose — One to 2 table-spoon*, according to the age and strength of the patient, J hour boV • nioals and at bed time.
This, or any othar alterative, when given, should be followed up for weeks or months, according to the disease for which it is prescribed, as scrofula, and for every disease depending upon an impure condition of the blood. It oughx to be used in sore eyes of long standing, old ulcers, salcrheum, &c. I would not give this for Jayne's Alterativo, nor Swain's, Townsend's or Ayer's Sarsaparillas, because I know it is good, and we also know what it is made of.
2. Altebativb, Vert Strok^g. — Poke, mandrake, yellow dock, sassafras, blue flag, roots, and bark of the roots, guaiac wood raspmgs, and sweet elder flowers, of each 4 ozs. ; caraway seed 3 ozb. ; bruise the roots, and put to the whole, alcohol 1 qt., and water to cover all handsomelj'- ; let stand 3 or 4 days in a warm place as the last recipe above, making every way the same except to pour off 1 qt., instead of 1 pt., as in the first, of spirit ; then boil the waters to 1 qt., adding 4 lbs. of sugar with the qt of spirit tincture. The dose being only 1 table-spoon 4 times daily as above.
But if that amount should make the bowels too loose, reduce the quantity ; and if that amount does not act upon ihe bowels at all, increase the dose to keep the bowels solvent. This may be used in the most inveterate diseases ei* long standing, syphilis not excepted.
8. Alterative Cathartic — Powder. — Rochelle salta 5 oz8.| oream of tartar 2 ozs. ; sulphur 1 oz. ; (epsom salts may be udet* but are not quite as good,) place the salts in a dripping-iAn and set in the stove oven until all the water of crystalization is dried out ; then place all in a mortar and rub finely and thoroughly
togetliei. DosB — Mix up a few spoons of the powder with mo .asses ; then take a tea-spoon every 3 or 4 hours until a fre» cathartic action is kept up for 24 to 36 hours ; then take once ov twice daily only, to act on the blood, increasing once in 10 day* to get up the cathartic action, as at first.
This alterative is especially valuable in any disease of the skin, as itch, pimples, salt-rheum, and any other eruptions where an outward application is being made, or ia about to be made, also valuable in sore eyes.
<L Altkrative, Tonic, and Cathartic Bitters. — Best rye whisky, and water, of each, 1 qt. ; best ungroimd Peruvian bark, Colombo root, and prickly-ash berries, of each, 2 ozs. ; pricklyash, black cherry, and poplar barks, of each, 1 oz. ; poke-root, mandrake-root, and cloves, of each, i oz. ; all to be the dry articles, and all to be pulverized before putting into the spirits ; Bhake every day for a week, by which time it will be ready for lase. DosK — One to 2 table-spoons at morning and evening meals.
Although this alterative is mentioned last in the list, yei it is not least in value. I first made this prescription for my own use, feeling that I needed something of just such » nature, and it worked so admirably that I gave it to others. It has given such entire satisfaction, that I am now at the tenth edition, giving it a place to do a greater good than if kept from the world.
If, in any case, it causes any griping sensations, or too great action upon the bowels, lessen the dose, and if neither of these actions are felt, increase the dose, or take it three times daily. I think any of the fruit wines will do in place of the spirits and water, by adding alcohol one-half pint.
It will be found very valuable in all cases of weakness from general debility, and especially so when tLe liver is inactive, known by constant costiveness.
After using out the spirits, it may be filled again iu the same way. It will be found very valuable in ague, ana after all fevers, preventing relapse, and strengthening up the general system.
DIURETICS— Pill, Drops, Decoction, &c.— Solidified copaiba 2 parts ; alcoholic extract of cubebs 1 part ; formed into I)ill8 with a little oil of juniper. Dosb — One or 2 pills 3 or 4 times daily. Druggists can obtain them of Tilden & Co., New York.
This pill has been found very valuable in affecticns of th» kidneys, bladder, and urethra, as inflammation from gravel, gonorrhea, gleet, whites, lucorrhca, common inflammations. &c. For giving them a sugar coat, see that heading, if desired.
2. Diuretic Dkops. — Oil of cubebs i oz. ; sweet spirits of nitre ^ oz. ; balsam of copaiba 1 oz. ; Harlem Oil 1 bottle ; oil of lavender 20 drops ; spirits of turpentine 20 drops ; mix. Dose — Ten to 25 drops, as the stomach will bear, 3 times daily.
satisfaction.
3. Diuretic Decoction. — Queen of the meadow, dwarfelder, yellow dock and poke-roots, of each 1 oz. ; dandelion, burdock, American Sarsaparilla, and blue flag roots, of each i oz. ; grind or pound all up, and thoroughly mi.x. Dose — Take up a pinch with the ends of the fingers and thumb of one hand, say J to J oz., and pour upon it 1 pi. of boiling water, steeping awhile ; when cool, take a swallow or two sufficiently often to use up the pt. in the course of the day.
Follow this plan two or three days, or as may be necessary, resuming the course once in ten or twelve days. It may be used in all obstructions of the kidneys, where the urine la high colored or scanty.
put into a bottle and covered with gin, is an excellent diuretic.
5. Diuretic for CniLDREX. — Spirits of nitre — a few drops in ft little spearmint tea — is all sufficient. For very young children pumpkin seed, or watermelon seed tea is perhaps the best.
DROPSY. — Syrup and Pills. — Queen of the meadow root dwarf-elder flowers, berries, or inner bark, juniper berries, horseradish root, pod milkweed or silkweed, often called, root of each 4 ozs. ; prickly-ash bark or ben'ies, mandrake-root, »'=i*<»rpweet bark of the root, of each 2 ozs. ; white mustard seed 1 oz. • nollaud gin 1 pt.
l*our boiling water upon all, except the gin, and keep "hoi for twelve hours ; then boil and pour off twice, and boi. down to three quarts and strain, adding three pounds of sugar, and lastly the gin. Dose — Take all the stomach will bear, four times daily, say a wine-glass or more. This will be used in connection with the following :
2. Dropsy Pills. — Jalap 50 grs. ; gamboge 30 grs. ; podo phyllin 20 grs. ; elaterium 12 grs. ; aloes 30 grs. ; cayenne &e grs. ; east^e «oap shaved, dried and pulverized, 20 grs. ; croton ou 90
Irops ; powder all finely, and mix thoroughly ; tlien form into pill mass by using a thick mucilage made of equal pa/ts of gum arable and tragacanth, and divide into S gr. pills. Dose — One pill every 2 days for the first week, then every 3 or 4 days until the water is evacuated by the combined aid of the pill with the above syrup.
In this disease the work must be very thorough, and I am inclined to think that if our directions are followed, that whoever find themselves under the operations of the medir eine will consider the work to be about as thorough as we expect. Some sickness of the stomach may be expected under the operation of the pill, but never mind it, go ahead and four or five days will satisfy most persons of the value of the treatment ; for you may expect to see the greatest evacuations, front and rear, that you ever have witnessed. Tf the patient should become weak and exhaust 5d under tha continued treatment, slack up a little and throw in beef tea, wine, &c., with rich nourishing diet, and no danger need be apprehended. The above pill will be found very valuable in bilious colic, and other cases hard to operate upon. They have operated in fifteen minutes^ but not usually so quick, of course j but it will generally be found best not to venture over one pill at a dose ; two have been taken, however* but they made a scattering among the waste paper, causing fourteen evacuations, having to call for the second " chamber" the first fire. Some have called them the " Irish Pill,*' from their resemblance to the Irish girl with her brush and Bcrub-broom. They make clean work.
IRRITATING PLASTER. -Extensively Used by Ecleorics. — Tar 1 lb. ; bur^indy pitch \ oz. ; white pine turpentine * oz. ; rosin 2 ozs. Boil the tar, rosin and gum together a short time, remove from the fire, and stir in finely pulverized mandrake root, blood root, poke root, and Indian turnip, of each 1 oz.
This plaster is used extensively lu all cases where counter irritation or revulsives are indicated ; as in chronic afieotions of the liver and lungs, or diseased joints, &c. It ia applied by spreading it on cloth and over the seat of pain, renewing it every day, wiping off any matter which may be on it, and also wiping the sore produced by it with a dry cloth, until relief is obtained, or as long as the patient caa bear it. Always avoid wetting the sore, as it will cause iuflammation, and you will be obliged to heal it «p imme^
ately, instead of which the design is to keep a running ton as long as may be necessary, using at the same time constitutional remedies as the case may require.
INFLAMMATION, — Op the Liver.— Inflammation of the liver, or as it is generally called, " Liver complaint," is of two forms, acute and chronic. The acute form ia known by a sense of weight and pain in the right side, under the short ribs, and often in that shoulder, or between the shoulders, pale or yellow appearance, often great depression of spirits, not much appetite, costiveness, high colored urine, &c., and often with fever, and sometimes with pain similar to that of pleurisy, difficult breathing, dry cough, and sometimes sickness, with vomiting.
In the chronic, or long standing complaint, in addition to the above, there is generally flatulence, with pain in the stomach, foul breath and mouth, coated tongue, indigestion, eyes yellow, stools clay colored, with great weakness and slow emaciation, frequently going on to ulceration, giving symptoms as mentioned under the head of " Ointment for Ulcerated Liver," &c.
In the acute form you will pursue the same course aa mentioned under the head of "Pleurisy," besides taking either of the Liver Pills or Liver Drops mentioned below, in full cathartic doses, until relieved ; but in the chronic form, the Pills, in connection with the " Ointment," or " Irritating Plaster," will be found all sufficient, unless Jaundice has already set in j then look to the directions under that disease.
2. Eclectic Liver I^l.— Podnphjlliu 10 grs. ; leptaodrln 20 grs. ; sanguinarin* 10 grs. ; extract of dandelion 20 grs. ; formed into 20 pills, by being moistened a little with some essential oil, as cinnamon or peppermint, &c. Dose — In chronic diseases of the liver, take 1 pill at night, for several days, or 2 may be taken at first to move the bowels; then 1 daily.
Im connection with the pill, wear the " Irritating Plaster," dver the region of the liver, washing the whole body daily, by means of towels, and rubbing dry, being careful noe to wet the sore caused by the plaster ; as an active cathartio
8. Liver Pill Imtroved.— Leptandrin 40 grs. ; podophyllin and cayenne, 30 grs. each ; sanguinarin, iridin and ipecac 15 grs. each ; see that all are pulverized and well mixed ; then form into pill-mass by using -J- dr. of the soft extract of mandrake and a lew drops of anise oil, then roll out into 3 grain pills.
Dose — Two pills taken at bed time will generally operate by morning ; but there are those that will require three, whilst one pill every night on retiring, will be found the best corrective of the liver of anything now in use, for common cases J but in very bad cases where the pill doef not arouse the liver to action, take the following :
4. LrvER Drops for Obstina.te Cases. — Tinctures of mandrake and blue flag roots, of each 1 oz. ; and of culvers root 2 ozs. Dose — For adults, 1 tea-spoon every 3 to 5 hours, increasing the dose gradually until you reach two or three tea-spoons, if the mouth does not become sore and the stomach not sickened nor the bowels moved too freely.
These drops are especially applicable in liver and spleen enlargements, and cases of very long standing disease of these organs ; and in such cases it may be well to use externally, over the liver and spleen, especialy if there is believed to be ulceration, the following :
a good handful of smartweed, wonnwood, and the bark of sumac root ; boil all together to get the strength, then strain and boil down carefully to about i pt., adding lard J lb., and simmering together ; when nearly cool add a tea-spoon of spirits of turpen tine.
Apply at night, by rubbing it over the liver or other organ which may have pain or disease located upon it, heating it in well by the stove or by a heated iron, putting it on, rubbing, and heating it in three or four times each application.
I obtained this prescription from the Rev. Mr. Fi-aser, of this city, whose nephew was so afflicted with ulceration of the liver that a council of Doctors said he must die ; the pain waa situated just under the short ribs of the right side, completely bowing him together, like the one of old who could " in no wise lift up herself." He had had a sister,
whr died some years before ; but at this juDcture ^ Am mm the invalid dreamed of meeting her, and sh'! gav« hiK ^w pr iscription, which he told his mother in the morning ; and ■jhe would not rest until it was tried, and it entirely cured *^fle patient. The Elder tells me he has given it to a great iiany persons, for pains of internal organs, ague cakes, &c., and that it has given great satisfaction — a perfect cure. The two first named articles I know to be good for what they are here recommended, but they are generally used by boiling and laying the herlDS over the affected parts, or by steaming the parts over the herbs. I see no reason why spirits frwn the other world should not be permitted to communicate with the spirits of friends here; but that they are so permitted, to communicate in such a way as to be understood by us frail mortals, I never did, nor do I now believe, neither i^.o I believe this to be the_;??-s^ dream of this character which I'as proved valuable. There are many things of a similar 'haracter in the history of a number of individuals in th« '•ange of my acquaintance, more singular and more unao countable than the above, which would be very interesting K) relate, but the nature of this work does not admit. If tjiis shall benefit any, I shall be satisfied.
Make into 40 pills.
Dose — Une pill to be taken an hour after breakfast, and one 1 an hour before retiring at night. Half a pill is enough for young, or verv old or yoxy delicate persons. Tlie pills may be easily cut if laid on a damp cloth for a few moments.
Theso. pills will be found applicable in bad Dyspepsia, nervou* hsadache, sleeplessness, palpitation of the heart, confusion of thought, determination of blood to the head, failure of ipemory, and all other forms of general nervous debility, no matter of bow long standing. Where a prominent advantage is discovced in two weeks from the commencement of the mcdicire, one a day will suffice until all are taken.
The extract is made by pulvenzing the seed or bean, and putting it into alcohol from ten to fourteen davs, then evaporating to the consistence for working i«to pill ma-ss with tha powdered gum.
This is the prescription of the Rev. John M. Dagnal, the ' Retired Physician," brought out in 1854, and to my attention, and that of the medical class, by Prof. Palmer, in the University of Michigan, in the winter of '56-7, He said when this prescription first came out he was practicing in Chicago, and many persons sent for the pills, and derived much benefit from their use, at first, but soon after they seemed to lose their efiicacy, and he presumed the reason to be that the demand was so great that something else waa substituted in place of the extract. This being the case, druggists ought to prepare the extract themselves, so as to furnish patients with the genuine article for home use. It i» undoubtedly a splendid prescription, if put up with fideUty
2. Pills — To Sugar Coat. — Pills to be sugar-ooated must be very dry, otherwise they will shrink away from the coating and leave it a shell, easily crushed off. When they are dry, you will :
Take rtarch, gum arable, and white sugar, equal parts, rubbing them very fine m a marble mortar, and if damp, they must be dried belbre rubbing together ; then put the powder into a suitable pan, or box, for shaking; now put a few pills into a small tin box having a cover, and pour on to them just a little simple eyrup, b! making well to moisten the surface only, then throw into the box of powder and keep in motion until completely coated, dry, and smooth.
If you aro not very careful you will get too much syrup upon the pi' Is; if you do, put in more and be quick about it to prevent moistening the pill too much, getting them into the powder as soon as possible.
3. Anodyne Pills. — Morphine 9 grs. ; extract of stramonium STid hyo^ciamus, of each 18 grs ; form into pill-mass by using solution of gum arable and tragacanth, quite thick. Divide into 40 pills. Dose — In case of severe i^ain or nervousness, 1 pUl taken at bed time will be found to give a quiet night of rest.
The advantage of this pill over those depending entirely npon opium or morphine for their anodvne Droperties, is, that they may be taken without fear ot consiipacion.
CROUP — Simple, but Effectual Remedy. — This disease is attended with inflammation of the windpipe, spasms of the muscles of the throat, occasioning a peculiar sound, bard to be describsd, but when once heard by a mother,
never to be forgotten ; cough, diflBicult respiration, and tevtit. The phlegm or mucous often filling, or very much obstructing the throat, and finally forming a false membrane which cuts off all possibility of breathing.
Eosed of equal parts of the tinctures of lobelia and blood-mot. I08E — According to the a§e of the child ; if 2 years old, about 1 tea-spoon every 10 to 15 mmutes until fre« vomiting takes place ', if 5 years old 3 tea-spoons, and increasing in proportion to age to 1 table-spoon for a child of 10 years, decreasing for very young children, say of 4 to 8 months, only 8 to 12 drops. Place tha feet as soon as possible into hot water, and keep them there until vomiting takes place, laying cloths wrun^ out of hot water upon the breast and throat, changing sufficiently often to keep them hot. The next morning give sufficient of the " Vegetable Physic " to move the bowels rather freely, "the emetic tincture should be given in some warm tea.
Repeat the emetic as often as the returning svmptoms demand it, which usually occur the following nighi, reoeating the cathartic every second or third day, and I will guarantee Buccess if commenced in any kind of reasonable time ; but usually no repetition will be needed if parents keep the preparation in the house so as to begin with the beginning of the disease.
2. Dutch Remedy.— Gtoose oil, and urine, equal quantities. Dose — From a tea to a table-spoon of the mixture, according to the a»e of the child. Repeat the dose every 15 minutes, if the first does not vomit in that time.
This remedy will be found valuable in mild cases, and where the first w not at hand ; and I know it to have saved a child when one of their best Doctors said it must die ; but bear in mind he had not used our first prescription j yet an old Dutch woman came in at the eleventh hour, from the next door neighbors' wash-tub, and raised the child with what she called " p — s and gooee grease." I have used it with success. ;
3. CnotJP OiNTMKNT.— Take mutton suet and nice lard, of each i lb. ; spermaceti tallow i oz. ; melt them together and add i pt. of the best vinegar, and simmer until the vinegar is nearly evaporated, skimming well, and constantly stirring, until it begins to granulate ; then add oils of amber and spruce, and pul verized sugar of lead, of each i oz. ; now remove from the fire and stir it tmtil cool. Dose— For a child of 3 jcars old, irit
from i to 1 tea-spoon every i hour, until relief i8 obtained, or until vomiting takes place ; at the same time rubbing it upon the chest, and over the throat and lungs, freely.
HYDKOPHOBIA AND SNAKE BITES— To PreVENT, AND Cure. — A. Hubbard, of Boone Co., 111., in a letter to the St. Louis Republican, says : " Eighteen yeara ago my brother and myself were bitten by a mad-dog. A sheep was also bitten at the same time. Among the many cuies oifered for the little boys, (we were then ten or twelve years/ old,) a friend suggested the following which he said would cure the bite of a rattlesnake :
" Take the root of the common upland ash, commonly called black ash, peel oflf the bark, boil it to a strong decoction, and of this, drink freely. Whilst my father was preparing the above, the sheep spoken of began to be afflicted with hydrophobia. When it had become so fatigued from its distracted state as to be no longer able to stand, my father drenched it with a pint of the asJi root ooze, hoping to ascertain whether he could depend upon it as a cure for his sons. Four hours after the drench had been given, to the astonishment of all, the animal got up and went quietly with the flock to graze. My brother and myself continued to take the medicine for 8 or 10 days, 1 gill 3 times daily. No effects of the dread poison were ever discovered on either of us. It has been used very successfully in snake bitoe, to my knowledge."
There is no doubt in the author's mind but wbat this gentieman has made a mistake in the kind of ash meant, as the upland ash is white-ash, from which flooring is made, having a thick, rough outside bark, whilst the black has a smooth bark, and grows in low, wet land, and is the same from which the flour barrel hoop is extensively manufactured. It is the upland white-ash that is to be used ; it is known, as he says, to cure rattlesnake bites, and a gentleman of this place has tried it with success in rheumatism, boiled very strong and taken in half gill doses. May vomit and purge if taken too freely. Yet a moderate action, either up or down, will not be amiss. I have cured a case of rheumatism, in a boy twelve or fourteen years of age, with the above, since it oame to my knowledge.
2. Saxon Remedy. — Gastell, a Saxon forester, now of the venerable age of eighty two, unwilling to take to the grave with him a secret of so much importance, has made public in the Leipsic Journal the means which he has used fifty ye^-'TS, and wherewith he affirms, he has rescued manj human jeings and cattle from the fearful death of Hydrophob'n.
'i'ake immediately atler the bite, warm vinegar or tepid water, "/ash the -wound clean therewith, and dry it ; then pour upon >he wound a few drops of hydrochloric acid, because mineral acids destroy the poison of the saliva.
3. Grecian Remedy. — Eat the green shoots of asparagus raw : sleep and perspiration will be induced, and the disease can bt thus cured in any stage of canine madness.
A writer in the Providence Journal, says a man in Athens, Greece, was cured of Hydrophobia by this remedy, even after the paroxysms had commenced.
4. Quaker Remedy — Fifty Years Successful. — Jacob Ely, a good old honest Quaker merchant, of Lloydsh ville, 0., gave me the following plan which his father had used since 1806 with success, to his knowledge, both on persons and domestic animals; and the New York Tribune ha« recently published something of the same character.
The dried root of elecampane, pulverize it and measure out 9 heaping table-spoons, and mix it with 2 or 3 tea-spoons of pulverized gum arable ; then divide into 9 equal portions. When a person is bitten by a rabid animal, take one of these portions and steep it in 1 pt. of new milk^ until nearly half the quantity of milk is evaporated ; then stram, and drink it in the morning, fasting for 4 or 5 hours after. The same dose is to be repeated 3 moniiuge in succession, then skip 3, and so on until the 9 doses are taken.
The patient must avoid getting wet, or the heat of the Bun, and abstain from high seasoned diet, or hard exercise, *nd, if costive, take a dose of salts. The above quantity it for an adult — children will take less according to age. Th« Tribune's publication is as follows :
If there is any virtue in the elecampane, at all, the preference, of course, is to be given to the Quaker's plan, which gives nine instead of three doses. But it bubscanciates Mr Ely's plan, as it comes from the place of his facher's former residence. Consequently it would seem to atreagthen coai dence in the first.
6. Snake Bites. — In case of being bitten by any of the po' Bonous snakes, tlie best plan is to wash oflF the place immediatdy then if the position of the wound is such th.at you can get th» mouth to the spot, suck out all the poison iu that way, or if anj other person is present, whose mouth is not sore, no dangeJ need be apprehended.
For all the poison may be upon the outside, and washed off, yet most likely penetrates more or lass into the wound, if a snake bite, as the arrangement of their teeth is aach that the poison comes out near the point and when in the wound, thus you see the propriety of aucking it out. Or :
7. Spirits of ammonia, a small vial of it, can be carried in the pocket, and if bitten, sharpen a little piece of wood to a small point, dipping this stick into the ammonia, and then penetrating the wound wath it. A piece of lunar caustic can be carried ii the pocket, and sharpened, if needed, and used the same as the stick and ammonia — and one of the celebrated English fanners has reported that this caustic, used freely on the bite of the mad dog, destroys the poison ; but to insure even a reasonable hope of success, it must be used immediaUly. This holds good in any of the sucking or caustic applications.
The National Intelliffencer, a year or two since, published a recipe for th« cure of the rattlesnake bite, which it claimed was infaixlble, it having been tried in a number of eases, and always with success. It was nothing more nor !«ss than the use of whisky as above recommended, and it
is but jnstice to say that a daughter of Wm. Reed, of the town of Pittsfield, in this county, who was bitten on the arm Bome three years ago, was cured by drinking whiaky until drunkenness and stupor were produced, and she has nevei felt any inconvenience from the bite since, which goes to show that the bite of the DeviTs tea is worse than the bit* of a rattlesnake.
9. I know an old physician who was called to a boy bitten by a rattlesnake, and in the absence of all other remedies, he cured him upon the principle that, " The hair of the iog will cure his bite," taking a piece of the snake about two inches long, splitting it on the back, and binding it upon the bite. It cleansed the wound very white, and no bad effecta were seen from it.
10. Saleratus, moistened and bound upon the bite ; then dissolve more, and keep the parts wet with it for a few hours has cured many massasauger-bites, as also bee-stings.
11. Snake Bitten Cattle. — Remedy. — Cattle or hot Bes zre usually bitten in the feet. When this is the case, ah that is necessary to do is to drive them into a mud-hole and keep them there for a few hours ; if upon the nose, bind the mud upon the place in such a manner as not to interfere with their breathing. And I am perfectly satisfied that Boft clay mud would be an excellent application to snakti bites on persons, for I know it to draw out the poisoning from ivy, and have been assured that it has done the same for snake bites, of persons as well as for cattle.
EYE preparations-Eye water.— Table salt and white vitriol, of each, 1 table-spoon ; heat them upon copper or earth en until dry ; the heating drives off the acrid or biting watercalled the water of crystalization, making them much milder in, their action ; now add them to soft water ^ pt. ; putting in white sugar 1 table-spoon ; blue vitriol a piece the size of a commen pea. If it should prove too strong in any case, add a little more Boft water to a vial of it. Apply it to the eyes 3 or 4 times daily
If the eyes are veri/ sore, or if the soreness has been of long standing, take the " Alterative Syrup," or the " Cithartic Alterative," continuing them for several weeks accord ing to the necessities of the case. I find it an excellent plan, in using any preparation for sore or weak eyes, to apply it again about twenty uiinutea from the first applkn-
tioi.. More than double speed is made by this repetition. For inflammation of any part of the body, apply this bj wetting cloths. Even for sores about the ears and groins of babes, reduce it, and three or four applications will cure tuem. I have also found it valuable for horses, as a wash, wncn they get the eye injured by straws, or otherwise, which twases the eye to water, or matierate, using it freely.
The use of this eye water enabled me to lay by the spectacles after four years' wearing, and I have since studied luedicine and graduated as a physician, without resorting a^ain to their use, by the occasional application of the ey« wator. But I need not have resorted to the use of the eye water again, had I not done ia study, as I do in all things «ise, that is, when I have anything to do, I do it with all my might. I read steadily, day by day, sixteen hours — a)ore than five other students, read altogether, who roomed tit the same house. Yet this counted in the end ; for when fhe class began to inquire and look around, near the end of the term, for one to deliver the Valedictory^ on their behalf, which is the custom in the Eclectic Medical Institute, I reoivftd that, the first honor of the class. I do not mention this to boast, by no means, but to show the necessity, as weli as the advantages, of hard study, especially to those who begin their studies late in life, and are obliged to pay their way with their own hands, and support a family also. This was my case exactly. In the commencement of my medical studies, I worked all day, reading half of the night, copying ofi" the latin terms, with their significations, on a slif of paper, which I carried in my pocket during the next day^ looking at two or three of the terms at a time, through the day, until all were committed. And thus I accomplished, • no more than what any other man may do, if he goes at it with a will, and does as I did ; and that some one may be •timulated to this course is the only object of this recitaL See " Advice to Young Men."
2. D . Raymond, of Grass Lake, Mich., who obtained the abo\ i prescription of me, adds to each ounce of water Qsed, out grain of morphine, and he tells me he has great auccesa with it; the addition of the morphine making it nearly resemble the celebrated prescription used by the English Bxirgeons in India, which is as follows :
3. India Prescription for Sore Eyes. — Sulphate of zinc 2 grs.; tincture of opium, (laudanum) 1 dr.; rose water 2 ozs.; mix. Put a drop or two in the eye 2 or 3 times daily.
Sulphate of zinc 1 oz.; sugar of lead J^ oz.; precipitated carbonate of iron y^ oz.; salt, and sugar, of each 1 table spoon ;■ the whites of 2 eggs; solt water 33 ozs.; mix the whites of the eggs, zinc, salt, lead, sugar, and iron well together, then add the water.
6. For Excessive Inflammation of the Eyes. — Pov'tice by boiling a handful of hops in water, putting in from J^ to 1 dr. of opium, Avhile boiling ; when still warm, lay the hops over the eyes and keep them wet with the water 'n which they were boiled.
A lady who had been blistered and starved, / cording to the old plan, in this disease, was soon cured by Itiis poultic . ng and washing the eyes often with the hop-water contain ing the opium, with generous diet, &c., contrary to the expectations of friends, and the predictions of enemies, to the plan.
the eye, has cured bad cases.
10. Bon, an cg%^ remove the yolk, and hav-e ready equal yarts of sulphate of zinc and loaf sugar, pul rerized ; fill the place occupied by the yolk, and squeeze out the oil through e Rnen cloth, while hot, and apply as needed. If too strong, add a little rain water.
I sold a book to a Mrs. Johnson, in Wayrie county, Mich who had used this preparation very succe^jsiully for several years, and had I not have aljiidy had ;c in my book, I
(jould not have purchased it of her for less than five dollars and she regretted very much that I was taking from her a source of profit by selling the books in her neighborhood containing the recipe.
11, Sailok's Eye Preparation. — Bum alum, and mix it with the while of eggs and put between two cloths and lay it apon the eyes ; taking salts and cream of tartar, equal parts, to cleanse the blood.
This was given to me, and very highly recommended, hy an old Scotch sailor, with whom I have had much enjoy ment, talking over the sufiforings of the sea, he having used it many times in places where nothing else could be obtained.
13. Father Pinkney's Preparation for Very Bad Sorb Eyes — Castile soap, scraped fine, and half the quantity of very finely pulverized chalk ; wet them up to a paste with strong juice of tobacco ; when desbed to apply to the eye, drop two or three drops of brandy into the box of paste ; then take ou* a bit of it where the brandy was dropped, equal in size to tl^ fourth of a grain of wheat, to the diseased eye ; wet it on a bit of glass, and put it into the eye with a camel's hair pencil.
Apply it twice daily at first, and from that to only once in two days, for from one to two weeks, will, and has cured wretched bad cases, so saj's old Father Pinkney, of Wayne Co.. Mich., who has used it over fifty years, he being over ninety years of age. Uis only object in giving it an insertion here is to do good to his fellow creatures ; and also for animals, it being equally applicable to horses or cattle.
13. Indian Eye Water.— Soft w^ater 1 pt. ; gum arable 1 oz ; white vitriol 1 oz. ; fine salt i tea-spoon; put all into a bottle and shake until dissolved. Put ipio the eye just as you retire to btjd.
I paid Mrs. Pinny, south of Ypsilanti, Mich., fifty cent* for this prescription. She would not, however, let her own family know its composition. Her husband had removed films from horses' eyes with it, and cured Mr. Chidister, a merchant of Ypsilanti, by only two applications, as the saying is, after he had " Tried everything else." It came from an old Indian, but my knowledge of the articles would lead me to say for common, at least, it would require to be reduced one-half.
necessary.
15. Verdigris and Honey, have cured inflamed eyes, by using just e-afflcient verdigris to color the water a grass color, then making it one-third honey. It is also said to prevent scara by using upon burns.
tion, used as above.
18. Films — To Remove from the Eye. — Wintergreen leaf, bruised, and stewed in a suitable quantity of hens' oil to make the oil strong of the wintergreen — strain and apply twice daily.
The above cured a boy of this city, and T am satisfied thai the hens' oil has cured recent cases, without the wintergreen, but with it, it has cured beasts also. For cases of a year or two's standing, however, it is best to use the following :
19. Lime water 1 pt. ; finely pulverized verdigris j oz. ; set on smbers for 1 hour; then strain and bottle tight. Touch the ilni over the pupil, or on the speck, 2 or 3 times daily, by putting the point of a small camel's hair pencil into the preparation, then to the eye, holding away the lids for a short time by placing the thumb and finger upon them for that purpose.
It will be found necessary to persevere for two or three months with this application, and also to use one of the " Alteratives," to cleanse the blood. This course, pursued for three months, gave sight to a young lady who had not seen light for two years, which Doctors could not do, nor were willing for others to do.
20. Eye Salve.— Take white precipitate 1 tea-spoon and rub it into a salve with 3 tea-spoons of fresh lard, and applied upon the outside of the lid of the worst chronic, (long continued), sore eyes, has cured them when they were so bad that even the eyelashes, (cilia), had fallen out, Irbm the disease.
not cure himself.
21. Sore Eyes— To Remo\'e the Granulations.— Crystal ized nitrate of silver 2 grs. ; morphia 1 gr. ; blue vitriol 1 gr. ; galammeniac 1 gr. ; pulverize each one separately, and mix.
22. Another Method — Is to take a stick of tag-alder about 2 feet long, boring a hole nearly through the middle of the stick, crosswise, filling it with salt, and plugging it up ; then put one end into the fii'e and char it nearly to the salt, then the other end the same way; and finally pulverizing and applying the gait, the same as the above, once daily only.
In either case after the granulations (little lumps) are removed from the eye, or eyes, finish the cure by using any of the foregoing eye waters which you may choose ; all the time using some of the alteratives for cleansing the blood.
FEVER SORES— PLASTER, SALVES, &c.— Black Salve. — Sweet oil, linseed oil, and red lead pulverized, of each 1 oz. (or in these proportions). Put all into an iron dish over a moderate fire, stirring constantly, until you can draw your fingei over a drop of it on a board when a little cool, without sticking. Spread on cloth and apply as other salvea
My brother, J. M. Chase, of Caneadea, N. Y. says he has used this salve about fifteen years, and knows it to be one of the best in the world for all kinds of old sores, as ulcers, fever sores, and all inflamed parts, cleaning and taking out redness or inflammation, causing a white healthy appearance in a short time, and a certain preventive of mortiflcation &c., &c., as well as to prevent soreness in more recent cuts and bruises, also ; and from my own knowledge of a salve which is very similar, I have introduced it into this work, feeling assured that whoever may have occasion to try it, will not regret the space it occupies, especially after reading the following : A gentleman said to me during the past summer, " I will give you one of the most valuable salves in the world, for I cured a man's hand, with it, which was so swollen tliat it looked more like a ham than a hand j and two Doctors aaid it must be cut off, also ulcerated." When he told me how it was made, I opened my book to the above salve, which was precisely the same as the one he used.
R»d lead 1 lb. ; bees- wax and rosin, or eacn 3 ozs. ; linseed and sweet oils, of each 3 table-spoons ; spirits of turpentir ; 1 tca-^poon; melt all, except the first and last, together, thenstiii \n the lead and stir until cool, adding the turpentine.
purify the blood :
3. Ma^tdiiake root, dried and pulverized, i oz. ; blood root, ip the same way, i oz. ; form into pills with extract of dandelion. Dose — Three pills may be taken at bed time, for 2 or 3 daya, then add another pill, and at the end of a week take any cathar tic you choose; then take iodide of potash 10 grs., and put jt into a vial with 1 oz. of water, and take 20 to 30 drops of it in a liule more water, instead of the mandrake pill, for 3 or 4 days; then that pill again, as at first.
By the time you have gone around three or four timet*, the blood will be pretty thoroughly cleansed — do not be afraid of the mandrake pill, as it will not act as a cathartic, but simply work upon the blood — if it does, reduce the number. You will be pleased with this method of purifi cation
4. Indian Curk. — G. A. Patterson, of AshtwhuU, 0., Wiis cured by an Indian physician, in Cleveland, of ou© of the worst fever sores almost ever known. The muscles of his leg were so contracted that no vje could be made of his leg in getting about. Four mouths, and the following treat ment, did the work :
A syrup of Wahoo (Euonymus Atropurpureus) — and here let me say that the Wahoo is the great Indian remedy for purifying the blood — was made by boiling very strong, then molasses ana rum added to make it palatable and keep it from souring ; this was used sufficient to keep the bowels solvent, sometimes chewing the bark of the root from which the syrup is made, preferring it a part of the time to the syrup. The sore was dressed with the following salve : Rosin 1 lb. ; mutton tallow 1 lb. ; beeswax 1 lb. ; linseed oil 1 pt. ; ambrosial (highly flavored) soap 1| ozs. ; to make it, mix in an iron kettle and simmer 2 hours, stu'ring all the time. Spread on cloth, and apply as needed. Tho contracted muscles were anointed with skunk's oil only.
Mr. Patterson also extols it very highly for all common purposes. And as I have a few other recipes for fever eorea which have been so highly recommended by those who have used them, I cannot omit their insertion, and I would especially recommend the next one following, called :
5. Kitbidok's Salve. — Bitter-sweet and sweet elder roots, of each 1^ lbs. ; hop vines and leaves, and garden plantain, top and root, of each i lb. ; tobacco 1 three-cent plug. Boil all in rain water to get out the strength ; then put the herbs in a thick cl/Ab
And press out tht juice, and boil down carefully to J pt. ; then add unsalted butter 1 lb. ; bees-wax and rosin, of each 1 oz., and simmer over a slow fire until the water is all out.
I obtained the above from S. B. Newton, a farmer Doctor near Mooreville, Mich., who had cured fever sores, with it, of thirty-five years' standing ; used it also on swellings iu every case, once upon a boy who had an eye kicked out and Bwelled very bad j he keeps it in his stable all the time foi wounds of horses and cattle, in castration, &c.,&c. Iknow it must be a very valuable salve.
6. Fevkk Sore Poultice. — Sassafras, bark of the root, drie t and pulverized very fine ; make a bread and milk poultice quitd thin, and stir in of the above powder to make it of proper con sistence, applying 8 times in the 24 hours for 3 weeks ; then heal with a salve made by thickening honey to a salve with whea« Hour.
If there are loose bones it will be quite sore wh. !e they are working out, but persevere. A case was cured by it of twelve years' standing ; the same man cured eight other cases, never having a failure, and it has proved successful on an abscess of the loins also.
7. Yeast Poultice. — Fresh yeast, the thick part, thickened with flour and applied to fever sores has proved very valuable, contmumg it for several weeks, touching any points, which does not heal readily, with finely pulverized verdigris rubbed up with a littlb lard ; then putting the poultice directly over the whole again.
dark, as I have seen many cases which had been cured.
8. Salve for Fevhr Sores, Abscesses, Broken Breasts, &c. — Thoroughly steep tobacco i oz., in soft water 1 pt., straining out from the tobacco and boUing down to 1 gill ; then have melted, lard, rosin, and bees-wax, of each i oz. simmering to a thick salve, then stirring in 1 gill of old rum, and, if necessary, continuing the simmering a little longer. To be used as other salves.
9. Ointment. — Sweet clover (grown in gardens) stewed in ijurd ; then add bees-wax and white pine turpentine, equal parts, Jo form an ointment, is highly recommended.
10. Salve for Fever Sores, Cuts, &c. — Spirits of turpentine and honey, of each ^ pt., simmered over a slow fire until they unite by stirring ; then set aside to cool until you cart put in the yolk ot an egg without its being cooked by the heat ; stir it in and return it to the fire, adding camphor gum i oz., simmer and etir until well mixed.
By putting in the egg when cool, it combines with fha other, but if put in while the salve is hot it cooks, but doca not combine. This is vejy highly recommended, as abov« indicated.
11. William Howell, a farmer living about six milet from Jackson, Mich.,^ays he had a fever sore on his shio for twenty years, sometimes laying him up for months, auf* at one time preparations were made to cut off the limb, bu an old man, in New Jersey, told him to :
day, until healed, which cured him.
And he feels assured, from using it in other cases, that all will be pleased with it who have any occasion ibr its use Apply it oftener if it becomes too offensive.
HALVES. — GuEEN MouNT.UN Salve. — Rosin 5 lbs.; Burgundy pilch, bees-wa."?, and mutton tallow, of each } lb. ; oil of hemlock, balsam of fir, oil of origanum, oil of red cedar, and Venice turpentine, of each 1 oz. ; oil of wormwood ^ oz. ; verdigris, very finely pulverized, 1 oz. ; melt the first articles together and add the oils, having rubbed the verdigris up with a little of tlie oils, and P^^^ ''- i" with the other articles, stirring well ; then pour into cold water and work as wax until cooj enough to roll.
This salve has no equal for rheumatic pains, or weakness in the side, back, shoulders, or any place where pain ma.) locate itself. ^V'hcre the skin is broken, as in ulcers, and bruises, I use it without the verdigris, making a white salve, even superior to "Pelcg White's old salve." Ic is valuable in Dyspepsia, to put a plaster of the green salve over the t.tomach, and wear it as long as it will stay on, upon the bacK also, or any place where pain or weakness rauy locate, lu cuts, bruises, abrasions, &c., spread the vriihe salve urun cloth and apply it as a sticking plaster until ^vell ; for rheumatism or weakness, spread the green salve upon soft, leather and apply, letting it remain on as long as it will stay. For corns, spread the green salve upon cloth and put upon the corn, letting it remain until cured. It has cured them.
A gentleman near Lancaster, 0., obtained one of my books having this recipe in it, and one year afterwards he told me he had sold over four-thousand rolls of the salve, curing an old lady of rheumatism in six weeks, who haii
been confined to her bed for seven weeks, covering all the the large joints with the salve, without other treatment. For roUiug oiit salves, see the cut below.
2. CoxKijx's Celebrated Saia"e. — Rosin 4 lbs. ; bees-wax, burgundy pitch, white pine turpentine, and mutton tallow, each } lb. ; cataptior gum and balsam of tir, of each i oz. ; sweet oil I oz. ; iiud alcohol i pt. Melt, mix, roll out, and U8(. as other salves, ^\'oude^s have been done with it.
3. B.VLM OF Gilead Salve. — Mutton tallow ^ lb. ; balm of gilead buds 3 ozs. ; white pme gum 1 oz. ; red precipitate i oz. ; Lard soap i oz. ; white sugar 1 table-spoon. Stew the buds in tlie tallow until the strength is obtained, and press out or strain, scrape the soap and add it with the other articles to the tallow, usiii^' siiflicient unsalted butter or sweet oil to bring it to a proper cou»irileuce to spread easily upon cloth. When nearly cool, stir 01 the red precipitate, mixing thoroughly.
Thi.s may be more appropriately called an ointment. It lo used ibr cuts, scalds, bruises, &c., and for burns by spreading very thin — if -sores get proud flesh in them, sprinkle a little burned alum on the salve before applying it. It has been in use in this county about forty years, with the greatest success.
4. Adhesive Plastek, ou Salve, for Deep "Wounds, Cuts, &c., IN Place of Stitcues. — White rosin 7 ozs. ; bees-wax and mutton tjiUow, of each i oz. ; melt all together, then pour into cold water and work as wax until thoroughly mixed, then roll out mU) suitable sticks for use.
It may be spread upon firm cloth and cut into narrow strips. In case of deep wounds, or cuts, it will be found to firwiy hold them togethei", by first pressing one end of a strip upon one side of the wound until it adheres, then draw the edges of the wound closely together, and press down the other end of the strip until it adheres also. The strips should reach three or four inches upon each side of the cut, lind run in diiierent directions across €ach other, to draw every part of the wound firmly in contact It will crack eusiiy after being spread until applied to the warm flesh, ye \f wade any softer it cannot be be depended upon lor an^ (cii^jrl) of time, but as it is, it has been worn as a strengthening plaster, and remained on over a year.
APPARATUS FOR WAKING SALVES AND LOZENOEB
The above cut represents a board prepared with atnpa apou it of the depired thickness for the diameter of the rolls of salve, also a piece of board with a handle, with which to roll tne salve when properly cooled for that purpose. *lhe salve is laid between the strips, which are generally one inch thick, then, with the handle piece, roll it until that board comes down upon the strips which makes the rolls all of one size, use a little tallow to prevent sticking to the boards or hands ; then cut off the desired length and put a label upon them, to prevent them sticking to each other.
A roller, and tin-cutter, is also represented in the same cut, with which, and another board, ha^^ng thin strips upon it to correspond with the thickness of lozenges required, you can roll the mass down until the roller touches the strips ; and thus you can get them as well as the salve, of uniform thickness; then out out with the cutter, laying them upon paper until dry.
VERMIFCGEa.— Sastoxin Lozenges.— Santonin 60 ^rs.; pulverized sugar 5 ozs. ; mucilage of gnni tragacanth suflicient to make into a thick paste, worked carefully together, that the sautouiu shall be evenly mixed throughout the whole maw
then, if not in too great a hurry, cover up the mortar i^ which you have rubbed them, and let stand from 12 to 24 hours to temper; ac which time they will roll out better tlian if done unmediately ; divide into 120 lozenges. See apparatus, above, for rolling, and cutting out. Dose — For a child 1 year old, 1 lozenge, night and morning ; of 2 years, 2 lozenges ; of 4 years, 8 ; of 8 years, 4 ; of 10 years or more 5 to 7 lozenges ; in aU cases, to be taken twice daily, and continuing until the worms Itart on a voyage of discovery.
A gentleman came into the drug store one morning, with the remark, " Do you know what your lozenges have been doing ?" As though they had killed some one, the answer was, no, is there anything wrong ; he held up both handa together, scoop shovel style, saying, " They fetched away the worms by the double handful." It is needless to attempt to give the symptoms by which the presence of worms might be distinguished ; for the symptoms of nearly every other disease is, sometimes^ manifested by their presence. But if the belly be quite hard and unusually large, with a peculiar and disagreeable breath, in the morning, foul or furred tongue, upper lip swollen, itching of the nose and anus, milky white urine, bowels sometimes obstinately costive, then as obstinately loose, with a craving appetite, then loathing food at times; rest assured that worm medicine will not be amiss, whether the person be child, or adult. It would be well to take a mild cathartic after four to six days use of the lozenges, unless the worms have passed off sufficiently free before that time, to show their general destruction. Very high praise has also been given to the following :
2. Vermifuge Oil — Prof. Freeman's. — In the May number of the Eclectic Medical Journal of Cincinnati, 0., I find so valuable a vermifuge from Prof. Z. Freeman, that I must be excused for its insertion, as the articles can always be obtained, whilst in some places you might not be able to £et tho santonin called for in the lozenges. His remarks following the recipe will make all needed explanations, and give confidence in the treatment.
oil,/ ; fluid extract of spigelia, i oz. (pink) hydrastin 10 gw. ; eynip of menth. pip. J oz. (syrup of peppcrmiut.) Dose — To a cliild 10 years of age, a tea-spoon 3 times a day, 1 hour before each meal ; if it purges too freely, give it less often.
" This is an excellent vermifuge, tonic, and cathartic, and has never failed (as well as I can judge,) to eradicate worms, if any were present, when administered for that purpose I have given no other vermifuge for the last five years, and often one tea-spoon has brought away from three to twenty of the lumbrica. Only a few days ago I prescribed one fluid drachm of it, (about one tea-spoon,) and caused the expulsion of sixty lumbricoids, and one fluid drachm, taken a, few days afterwards, by the same child, brought away forty more, some of them six inches in length. Where no worms are present, it answers the purpose of a tonic, correcting the condition of the mucus membrane of the stomach and bowels, improving the appetite and digestion, and operating as a mild cathartic."
8. Worm Tea. — Carolina pink-root, senna leaf, manna, and American worm-seed, of Ciicli I oz. ; bruise and pour on boiling water 1 pt., and steep without boiling. Sweeten well, add half bs much milk. Dose — A child of five years, may take 1 gill 3 times daily, before meals, or sufficient to move the bowels rather freel}'.
If this does not carry ofl" any worms, wait one day and lepeat the operation ; but if the bowels do not move by the first day's work, increase the dose and continue to give it until that end is attained before stopping the medicine. This plan will be found an improvement upon the old where the lozenges or oil cannot be obtained, as above.
4. Worm Cake— English RE>rEDV. — Wheat flour and jalap, of each i lb. ; calomel, grain-tin, and ginger, of each 1 oz. Alix tlioroughly and wet up as dougli, to a proper consistence to roll out ; then roll out as lozenge cakes, to three-sixteenths of an inch in thickness ; then cut out f inch square and dry them. Dose — For a child from 1 to 2 years, f of a cake ; 4 to 5 years, 1 Ortke ; from 5 to 7 years, 1} cakes ; from 7 to 10, H ; from 10 to 13, If; from 1'2 to 14, 2; from 14 to 17, 2^; from 17 to 10 years, and all above that age, 2^ cakes, but all men above tliat age 3 cakes.
'•Children may eat them, or they can be shaved o? very fine and mixed in a little treacle, honey, or preserv^es. If after taking the first dose, they do not work a* you dewxfl,
increase the dose a little. The patient to take the medicine tw'ce a week — Sundays and Wednesdays. To be taken Id the morning, fasting, and to be worked off with a little warns tea, water gruel, or warm broth. N. B. — Milk must not be used in working them off, and be careful of catching cold.— Snodin, Printer, Oakham, Eng."
I obtained the above of an English family who praised it very highly as a cathartic for common purposes, as well an for worms. And all who are willing to take calomel, I have no doubt will be pleased with its operations.
TAPE-WORM. — Simple, but Effectual Remedy. — This, very annoying and distressing, worm has been removed by taking two ounce doses of common pumpkin-seeds, pulverized, and repeated every four or five hours, for four or five days; spirits of turpentine, also in doses of one-half to two ounces, with castor oil, have proved very effectual ; the root of the male fern, valerian, bark of the pomegranate root, &c., have been used with success. But my chief object in speaking upon this subject, is to give the successes of Drs. Beach, of New York, and Dowlcr, of Beardstown, HI., from their singularity and perfect eradication of the worm, in both cases : The first is from " Beach's American Practice, and Family Physician," a large work, of three t^olumes, costing Twenty Dollars, consequently not generally circulated ; whilst the latter is taken from the " Eclectic Medical and College Journal," of Cincinnati, and therefore only taken by physicians of that school. The last was first published by the " New Orleans Medical and Surgical Journal." First then. Dr. Beach says :
" The symptoms of a tape-worm, as related to me by Miss Dumouline, who had suffered with it for twenty-five years, are in substance as follows : It commenced at the age of ten, and afilicted her to the age of thirty-five. It caused symptoms of many other diseases, great wasting of the flesh, &c. Her appetite was very capricious, being at times good, and then poor for months, during which time her symptoms were much aggravated ; sickness, vomiting, great pain in the chest, stomach
and fiide, motion in the stomach, and also in the bowels, Tfitfc pain, a sense of fullness or swelling, and beating or throbbing in the same, dizziness, heaviness of the eyes : — and ehe was altogether so miserable that she feared it would destroy her. When she laced or wore anything tight, it produced great distress. The worm appeared to rise up in h«r throat and sicken her. Her general health was very bad. At intervals, generally some time after taking medicine pieces of the worm would pass from the bowels, — often as many as forty during the day, all alive, and would swim in water.
" Tkeatment. — ]VIl83 Dumo'iiine stated tliat she bad employed twenty physicians, at different periods, and taken a hundred different kinds of medicine without expelling the worm. She had taken spirits of turpentine, but could not retain it upon the stomach. Under these circumstances I commenced my treatment. Cowage shipped from the i)od, a small tea-spoon three times a day, to be taken, fasting, In a little arrow-root jelly ; then occasionally a purgative of mandrake. In connection with this, I directed her to eat freely of garlic, and common fine salt. I gave these under the belief that each article possessed vermifuge properties, without ever having administered them for the Uipe-worm. After having taken them for some time, all her unfavorable symptoms ceased, and subsequently the remaining portion of the worm passed lifeless from her — an unprecedented circumstance.
" She immediately recovered, and has since retained lier health, and there is no evidence that there is any remaining The patient stated that the worm which passed from her during the time she was afflicted with it, would fill a peck measure, and reach one mile in length. Her relief and gratitude may be better imagined than described. I have a portion of this worm in my possession. When once the tapeworm begins to pass the bowels, care must be taken not U» break it off, for it will then grow again — it has this pceuliai property."
2. Secondly, Dr. Dowler says : " The subject of this notice is a daughter of Mr. E. Fish, of Beardstown, 111., about six years old. The only point of special interest in the case consists in the efficiency of the remedy — to me wholly new, and accidentally brought to my notice — which was used in its treatment.
prescription for wliom was, as a drink, the mucilage of elm bark, made by putting pieces of the solid bark into water. The girl was seen to be frequently eating portions of the bark during the day ; the next morning after which, upon my visiting the boy, the mother, with much anxiety, showed me a vessel containing something that had that morning passed the girl's bowels, \^ith bits of the elm bark, enveloped in mucilage, which, upon examination, proved to be about three feet of tape-worm. As I supposed the passage of the worm was accidental, and had occurred from the looseness caused by the bark, I proceeded to prescribe what I supposed a much more potent anthelmintic, a large dose of turpentine and castor oil. The turpentine and oil were given Bevo.ral times during the three consecutive days, causing pretty active purging, but with no appearance of any portions of the worm. The girl being slender, and of irritable temperment, I was forced to desist from fuither active medications ; and partly to allay irritation oi the bowels, and partly to test the influence of the bark on the worm, I dire<?ted that she should resume the use of the bark as before, bv chewing and swallowing in moderate quantities.
" On visiting her the succeeding morning, I was shown portions of the worm, mostly in separate joints, that had beeu passed over night. Feeling now some contidence in the anthelmintic powers of the elm bark, I directed the continned use of it, in "the solid form, as before, while there ehould be any portions of worm passing. In my daily calls for nome days, I had the satisfaction to learn that portions of t he worm continued to pass, from day to day, and sometimf-8 several times a day.
" f now ceased to vist my little patient, intending only an occasional visit; but my confidence in the efficacy of the dm hark being so well established, I advised its use to be contiuued for even two or three days after any portions of the worm should be seen in the evacuations. The portions of the worm expelled — even the separate joints — were alive showing more or less motion ; a sense of their presence in the rectum, from their action, seemed to urge the patient to go to stool for their removal.
my notes of the case, I find that during about seven \Teefai of the intervening time, there had been expelled, by estimate, (taking the average lengths of the joints,) about forty' fioe, feet of worm. At this time there had been no portions of the worm pa.ssed for two weeks, during which time the use of the bark had been omitted. The head of the worm, with about fifteen inches of the body attached, tiad been expelled ! But thinking that all portions of the worm or worms might not have been removed, I advised that the patient should resume the use of the bark. Very soon the next day, after doing so, further portions commenced com mg away, among them one about iix, feet long, tapering to a thread-like termination.
" The next time I took notes of the case, my estimate of the entire length of the worm that had been expelled, footed up one hundred and thirti/-fve feet^ whether one or more worms, 1 am unable to say, as in the portions I saw., there- were a head and tail, of what I supposed one worm. Since the last estimate, there have b<jen joints occasionally evacuated
'' This patient, when first treated, was thin in flesh — had been growing so for some two years — attended with the usual nervous symptoms, starting out of sleep, variable appetite, ctv,., but with no great departure from good health.
" As to the influence of this very bland agent in the dialodgment of the tape-worm, in this case, I think there can be no doubt, whathever may be the theory of its action. *
" The pas.sage of portions of the worm, so promptly, od the use of the bark, and the ceasing to do so on the discon tiiiuauce of its use — even while active purgative anthelmintics were used — leave no room to doubt its effectiveness ij» at least this case, as a worm-expelling agent.
" It seems probable that the bark, with its thick mucil^ age so interposes between the animal and the inner surface of the bowels, as to prevent its lateral grasp on their surface in consequence of which it is compelled to yield to the force* naturally operating, and is carried out with the discharges. But as my object was simply to state the practical fact* iu this c-ase, I will ofier no further reflections.
grs. ; kennes mineral 50 grs. ; sulphate of morphia 8 grs. ; powdered white sugar, gum arable, aud extract of licorice, of each 1^^ ozs. ; oil of anise 20 drops ; syrup of tolu sufficient to work into mass form ; loil out and cut into 160 lozenges. Dose — One lozenge 3 times daily. — ParinlCa Pharmacy.
The above is tho prescription of the " regulars/' but there are those, perhaps who would prefer the more rational pro■ Bcriptioa of the " irregulars," next following ; and there are those who would prefer the " Cough Candy" in place of either of the lozenges. By the insertion of the variety, all can please themselves.
2. Cough Lozenges. — Another valuable lozenge is made as follows : Extract of blood-root, licorice, and black cohosh, of eaijU i oz.; tinctures of ipecac and lobelia, with laudanum, of each J oz. ; cayenne, powdereu, 10 grs. ; pulverized gum arable and starch, of each f oz. ; mix all together, and add pulverized sugar 3 ozs. K this should be too dry to roll into lozenges, add a thick solution of gum arable to give it that consistence ; and if it should be yet too moist, at any time, add more sugar. Divide into 320 lozenges. Dose — One, 3 to 6 times daily, as needed.
8. PcTLMONic Wafers. — Pulverized sugar 7 ozs. ; tinctm-e of ipecac 3 drs. ; tincture of blood-root and syrup of tolu, of each Z drs. ; tincture of thoroughwort | oz. ; iiiorphine 1^ grs. Dissolve ike morphine in water ^ tea-spoon, having put in sulphariE ivld 2 drops ; now mix all, and add mucilage of comfrty rcvi on gum arabic, to form a suitable paste to roll and cut into ooiVLi'Uiijized wafers or lozenges. Diuections. — Allow 1 to djj.\>.\ve ia the mouth for a dose, or dissolve 6 in 3 tableBpooaij i>i warm water, and take ^ oi a. spoon 6 times daily, or oftcner if ufccl be.
faction :
5. Cough ^Mixture for Recent Colds. — Tincture of blood-root, syrups of ipecac and squills, tincture of balsam of tolu, and paregoric, equal parts of each. Dose. — Half of a tea-spoon whenever the cough is severe. It is a verj valuable medicine.
_ 6. Cough Candy. — Tincture "^f squills 2 ozs. ; camphorated tincture of opium, and tincture of tolu, of each J- oz. ; wine of ipecac i oz. ; oils of gauLlheria 4 drops, sassafras 3 drops, and of aaise-seed oil 2 drops. The above mixture is to be put into 5
ing their own compound.
7. CoroH Sykup. — Wahoo, bark of the root, and elecampane root, of each 2 ozs. ; spikenard root, and tamarack bark (unrosa* ed, but the moss may be brushed off,) of each 4 ozs. ; mandrake root i oz. ; blood-root i oz. ; mix alcohol 1 pt., with sufficient water to cover all, handsomely, and let stand 2 or 3 days ; then pour off 1 qt., putting on water and boiling twice, straining the two waters and boiling down to 3 pts. ; when cool add 3 lbs. of honey, and alcoholic fluid pomed off, with tincture of wine of ipecjic H 0Z8- ; if the cou^h should be very tight, double the ipecac ; and wash the feet daily in wann water, rubbing them thoroughly with a coarse towel, and, twice a week, extending the washing and rubbing to the whole body. Dose. — One tablespoon 3 to 5 times daily.
If the cough is very troublesome when you lie down at night or on waking in the morning, put tar and spirits of nitre, of each one tea-spoon into a four ounce vial of water shaking well; then at these times just sip about a tea-spoon from the bottle without shaking, which will allay the tickling sensation, causing the cough.
1 have cured a young lady, during the past winter, with the above syrup, whose cough had been pretty constant i'cwr over two years ; her friends hardly expected it ever to be any better, but it was only necessary to make the above amount of syrup twice to perform tlie cure.
8. Cough Tincturk. — Tinctures of blood-root and balsam of tolu, of each four ounces ; tinctures of lobelia and digitalis, of each two ounces; tincture of opium (laudanum") one ounce; tincture of oil of anise (oil of anise one-half tea-spoon in an ounce of alcohol,) one ounce. Mix. DosB. — About one-half tea-spoon three times daily, in the same unount of honey, increasing to a tea-spoon if needed to loosen and lessen the cough. It has raised cases which doctors said must die, causing the patient to raise matter reaembling the death-smell, awful indeed. It will cure cough, not by stopping it, but by loosening it, assisting the lungs and throat to throw oflf the oflfending matter, which causes the cough, acd thus sct'entiJicaUj/ making th« c\ue
(perfect; while most of the cough remedies kept for Bale, Biop the cough by their anodyne and constringing effects, retaining the mucus and all offending matters ia the blood, causing permanent disease of the lungs.
But, notwithstanding the known value of this " Cough Tincture," where the tamarack and other ingredients can be obtained, I must give my preference to the " Cough Syrup," No. 7.
9. Cough Pill.— Extract of hyoscyamus, balm of ^ilead ■buds, with pulverized ipecac, or lobelia, and balsam of tir, of each i oz. ; oil of anise a few drops to form into common sized pills. Dose — One or 3 pills 3 or 4 times daily.
Dr. Beach says he endeavored for more than twenty-five years to obtain a medicine to fulfill the indications which arc effected in this cough pill, particularly for ordinary colds and coughs ; and this admirably answers the intention, excelling all others. It allays the irritation of the mucus membrane, the bronchial tubes, and the lungs, and will be found exceedingly valuable in deep-seated coughs and all diseases of the chest. The bad effects of opium (so much used in coughs) are in this pill entirely obviated, and it is altogether bettxir than the Cough Drops, which I now dispense with. — Beach's American Practice.
WHOOPING COUGH— Strup.— Onions and garlics, sliced, of each 1 gill ; sweet oil 1 gill ; stew them in the oil, in a covered dish, to obtain the juices ; then strain and add honey 1 gill ; parCj^oric and spirits of camphor, of each \ oz. ; bottle and cork tight for use. Dose — For a chdd of 2 or 3 years, 1 tea-spoon 3 or 4 times daily, or whenever the cough is troublesome, increasing or lessening, according to age.
This is a granny's prescription, but I care not from what cource I derive information, if it gives the satisfaction that this has done, upon experiment. This lady has raised a large family of her own children, and grand children in abundance. We have tried it witL three of pur childrca also, and prescribed it in many other cases with satisfaction, for over seven years. It is excellent also in common colds p1.tended with much cough. This is from experience, too, whom I have found a vory competent teacher.
2. Dailey's Whooping Cough Syrup. — Take the strongest West India rum, 1 pt. ; anise oil 2 ozs. ; honey 1 pt. ; Iciuun juice 4 ozs. ; mix. Dose — For adults 1 table-spoon 3 or 4 times a day, — children, 1 tea-spoon, with as much sugar and watei.
Spikenard root, bruised and steeped in a tea-pot, by using half water and half spirits ; then inhalinj? the steam, when not too hot, by breathing through the spout, will relieve the soreness and hoarseness of the lungs, or throat, arising fi'om much coughing.
IN-GROWING TOE NAIL— To Cure.— We take the following remedy for a very common and very painful affliction, from the Boston Medical and Surgical Journal:
" The patient on whom I first tried this plan was a young lady who had been unable to put on a shoe for several months, and decidedly the worst I have ever seen. The edge of the nail was deeply undermined, the granulations formed a high ridge, partly covered with the skin ; and pua constantly oozed from the root of the nail, The whole toe was swollen and extremely painful and tender. My mode of proceeding was this :
" I put a very small piece of tallow in a spoon, and heated il «ntil it became very hot, and poured it on the granulations. The effect was almost magical. Pain and tenderness -were at once relieved, and in a few days the granulations were all gone, the diseased parts dry and destitute of all feeling, and the'edge of the nail exposed so as to admit of being pared away without tiny inconvenience. The cure was complete, and the trouble never returned.
" I have tried the plan repeatedly since, with the sam* satisfactory results. The operation causes but little pam, iif the tallow is properly heated. A repetition in some caaea might be necessary, although I have never met with a easje that did not yield to one application." It has now been proven, in many other cases, to be effectual, accomplishing; in one minute, without pain, all that can be effected by the painful application of nitrate of silver for several weeks*.'''
OILS — British Oil. — Linseed and turpentine oils, 'i/ eaci" < ozs. ; oils of amber and juniper, of each 4 ozs. ; Barbadoea Ur 8 oza. ; seneca oil 1 oz. ; lliz.
This 19 an old prescription, but it is worth the whole eoJt of this book to any one needing an application for cuts, bruises, swellings, and sores of almost every description, on persons, horses, or cattle ; so is the following, also :
3. Balm op Gilead Oil. — Balm of Gilead buds any quantity; place them in a suitable disn for stewing, and pour upon them sufficient sweet oil to Just cover them; stew thoroughly and press out all of the oil from the buds, and bottle for use.
3. Haklem Oil, ok Welch Medicamenttjm. — Sublimed or flowers of sulphur and oil of amber, of each 2 az. ; linseed oil 1 lb. ; spirits of turpentine sufficient to reduce all to the consistence of thin molasses. Boil the sulphur in the linseed oil until it is dissolved, then add the oil of amber and turpentine. Dose — From 15 t^ 25 drops, morning and evening.
Amongst the Welch and Germans it is extensively used for strengthening the stomach, kidneys, liver and lungs, asthma, shortness of breath, cough, inward or outward Bores, dropsy, worms, gravel, fevers palpitation of the heart, gMdiness, head-ache, &c., &c., by taking it internally , and for ulcers, malignant sores, cankers, &c., anointing externally, and wetting linen with it and applying to burns. In fact, if one-half that is said of its value is true, no other medicine need ever be made. It has this much in its favor, however, — probably no other medicine now in use, has been in use half so long, — over 160 years. The dose for a child is one drop for each year of its age.
4. On. OF Spike. — The genuine oil of spike is made from the fa^ndvl^i sqdca (broad leaved lavender,) but the commercial oil of Bpike is made by taking the rock oil, and adding 2 ozs. of spirits ot turpentine to each pint.
tie, or an open crock until dissolved ; then slowly add olive oi] and spints of turpentine, of each i pt., putting m the oil first. Let the work be done out of doors to avoid the fumes arising from the mixture ; when all is done, bottle and put in all th« cotton cloths it will dissolve, when it is fit for use.
The mixture becomes quite hot, although no heat is used in making it, from setting free what is called latent, or insensible heat, by their combining togetner. Rev. Mr. Way, of Plymouth, Mich., cured himself of sore throat by taking a few drops of this black oil upon sugar, letting it slowly dissolve upon the tofigue, each evening after preaching, also wetting cloths and binding upon the neck. It will be necessary to avoid getting it upon cotton or linen which you would not wish to show a stain. A colt which had a fistulous opening between the hind legs, from a snag, as supposed, which reduced him so that he had to be lifted up, when down, was cured by injecting twice only, of this oil to fill the diseased place. Also a very bad fever sore, apon the leg, ah ! Excuse mc, upon the limb of a young lady, wbich baffled the scientific skill of the town in which she lived. In ca.se they bite too much in any of their applicatiops, wet a piece of brown paper in water and lay it over the parts.
OPODELDOC— Liquid. — Best brandy 1 qt. ; warm it and add gum camphor 1 oz. ; salammoniac and oil of wormwood, of each J oz. ; oils of origanum and rosemary, of each i oz. ; when th« oils are dissolved by the aid of the heat, add soft soap 6 oz.
Its uses are too well known to need further description.
DLA-KRHEAS — Cokdial. — The best rhubarb root, pulverized, 1 oz. ; peppermint leaf 1 oz. ; capsicum i oz. ; cover with boiling water and steep thoroughly, strain, and add bi-carbonate of potash and essence of cinnamon, of each i oz. ; with brandy (or good whisky) equal in amount to the whole, and loaf sugar 4 oz. Dose — For an adult 1 to 2 table-spoons; for a child 1 tt 2 tea-spoons, trom 3 to 6 times per day, until relief is obtained.
This preparation has been my dependence, in my travel* and in my family for several years, and it has never failed us ; but in extremely bad cases it might be well to use, afler each passage, the following :
2. Injection Fon Chrokic Diakkhka. — New milk, with thic* mucilage of slippery elm, of each 1 pt. ; sweet oil 1 gill ; molasses i pt. ; salt 1 oz ; laudanum 1 dr. Mix, and inject what ih« Dowels will retain. .
Very many children, as well as grown persons die, annually, of this disease, who might be saved by a proper use of the above injection and cordial. The injection should ne^er be neglected, if there is the least danger apprehended.
Although I believe these would not fail in one case out of one hundred, yet I have some other prescriptions which are so highly spoken of, I will give a few more. The first from Mr. Hendee, of Warsaw, Indiana, for curing Diarrhea, or Bloody Flux, as follows :
3. DiRARRHEA TiNCTURE. — Compound tincture of myrrh 6 ozB. ; tincture of rhubard, and spirits of lavender, of each 5 ozs. ; tincture of opium 8 ozs. ; oils of anise and cinnamon, with gum camphor and tartaric acid, ot each i oz. Mix. Dose — One tea-spoon in ^ a tea-cup of warm water sweetened with loaf sugar ; repeat after each passage.
again :
4. DiARRHBA Drops. — Tincture of rhubarb, and compound spirits of lavender, of each 4 ozs. ; laudanum 2 ozs. ; cinnamon oil 2 drops. ;Mix. Dose — One tea-spoon every 3 or 4 hours, according to the severity of the case.
This speaks from ten years successful experience.
5. Diarrhea Syrup — For Cases brought on by LongConTTNUED Use op Calomel. — Boxwood, black cherry and prickly *sh barks, with dandelion root, of each 2 ozs ; butternut bark 1 oz. ; boil thoroughly, strain and boil down to 1 qt. ; then add loaf sugar 2 lbs., and alcohol 1 gill, or brandy i pt. Dose — A wine-glass from 8 to 5 times daily, according to circumstances.
This regulates the bowels and tones up the system at the game time, no matter whether loose or costive. In one case of costiveness it brought a man around all right who had been sowed up tight for twelve days. On the other hand, it has regulated the system after months of calomel-Diarrhea,
6. WiNTERGREKN Berries havc been found a valuable corrector of Diarrhea brought on by the long-continued use of calomel in cases of fever, eating a quart of them in 3 days time.
The gentleman of whom I obtained this item tells me that wintergreen essence has done the same thing, when the berries could not be obtained. In the first place, " everything else," as the saying is, had been tried in vain, and the taau's wife, in coming across the woods, found these berrici
and picked some, which when the husband saw, he crayed^ and would not rest without them, and, notwithstanding the fears of friends, they cured him. Many valuable discoveries are made in a similar manner.
For young children, in Diarrhea, or Canker, orwucn they are combined, feed a tea-spoon of it, or less, accoramg to the child's age, two or three times daily, until cured. To ovetcoHie costiveness, which may arise from its vae, scorch fresh butter, and give it in place of oil, and in quantities corresponding with oil. Children have been saved with three cents worth of this bark which " Alopath" said must die. If good for children, it is good for adults, by simply increasing the dose.
9. Sumac bobs, steeped and sweetened with loaf sugar, has been found very valuable for Diarrhea ; adding in very severe cases, alum pulverized, a rounding tea-spoon, to 1 pt. of tlie strong tea. Dose — A tea, to a table-spoon, according to the age of the child, and the severity of the case.
CHOLERA TINCTURE.— Select the thinest cinnamon bark, cloves, gimi ^uiac, all pulverized, of each 1 oz. ; very best brandy 1 qt. Mix, and shake occasionally for a week or two. Dose — A tea-spoon to a table-spoon for an adult, according to the condition and robustness or strength of the system. It may be repeated at intervals of 1 to 4 hours, if necessary, or mucL more often, according to the condition of the bowels.
This I have from an old railroad-boss who used it with hii men during the last Cholera in Ohio, and never lost a man. whilst other jobbers left the road, or lost their men in abund ance, thinking the above too simple to be of any value.
2. Isthmus Cholera Tinctcre. — Tincture of rhubarb, cay. . enne, opium, and spirits of camphor, with essence of peppermint, equal parts of each, and each as stron? as can be made Dose — From 5 to 30 drops, or even to 60, and repeal until relief ifi obtained, every 5 to 30 minutes.
alsw many others.
3 Cholera Preventive. — HoflFman's anodyne and essence of ptsrpermint, of each 2 ozs. ; tincture of ginger 1 oz. ; laudanuu /spirits of camphor, and tincture of cayenne, of each i oz. ; mix. Dose — For an adult, from a tea to a table-spoon, according o symptoms.
5. Gkrman Cholera Tincture. — Sulphuric ether 2 ozs. ; and pm mto it castor and gentian, of each i oz. ; opium and aganc, ^ach 1 dr. ; gum camphor i oz. ; let them stand 2 days, then adu alcohol 1 qt., and let stand 14 dS,ys, when it is ready for use. Dose. — One tea-spoon every 15 ©r 20 minutes, accordmg to yie urgency of the case.
I obtbaned this prescription of a German at Lawrenceburgh, Ijid., who had done very much good with it during the last cholera period in that place.
6. Egyi riAN Cure for Cholera. — Best Ja^naica ginger root, braised. 1 )z. ; cayenne 2 teaspoons ; boil all in 1 qt. of water to i pt., aud add loaf sugar to form a thick syrup. Dose. — One table-spoou every 15 minutes, until vomiting and purging ceases, then follow up with a blackberry tea.
The foregoing was obtained of a physician who practiced in Egypt, (^not the Illinois Egypt,) during the great devastation of the cholera tberf, with which he saved many lives.
7. India jf pj^scriptiom ?or Cholera. — First dissolve gum camphor i o/. \n IJ ozs. of alcohol — second, give a tea spoon of spirits of hartshorn in a wine glass of water, and follow it every 5 minutes wilh 15 drops of the camphor, in a tea-spoon of water, for 3 d^^F-es, then wait 15 minutes, and commence again as before, and continue the camphor for 30 minutes, unless there is returning heat. Should this be tha case, give one more dose and the cure is effected; let them perspire freely, (which the medicine is designed to cause,) as upon this the life depends, but add no additional clothing.
Lady Ponsonby, who had spent several years in India, and had proved the efficacy of the foregoing, returned to Dublin in 1832, and published it in the Dublin Mail, for the benefit of her countrymen, declaring that she never knew it U? fall.
cases of disease.
8. Nature's CnoLEUA Mkdictse. — Laudanum, spirits of camplior, and tinctui-e of rhubarb, equal parts of each. Dose — One table-spoon every 15 to 30 minutes until relieved.
In attacks of cholera, the patient usually feels a general uneasiness and heat about the stomach, increasing to actual distress and gi-eat anxiety, finally sickness, with vomiting and purging, surface constringed, the whole powers of the system concentrated upon the internal organs, involving the nervous system, bringing on spasms, and in the end, death. Now, whatever will allay this uneasiness, drive to the surface, correct the discharges, and soothe the nerves, caret the disease. The laudanum does the first and the last, the camphor drives to the surface, and the rhubarb conecta the alimentary canal ; and if accompanied with the hot bath, frictions, &c., is doubly sure. And to show what may be done with impunity in extreme cases, let me say that Merritt Blakeley, living near Flat Rock, Mich., came homo from Detroit, during the last cholera season, having the cholera in its last stage, that is, with the vomiting, purging and spasms j the foregoing medicine being in the house, the wife, in her hurry and excitement, in place of two-thirds of a table-spoon, she read two-thirds of a tea-cup; and gave it accordingly, and saved his life ; whilst if taken in the spoon doses, at this stage of the disease, he would most . undoubtedly never have rallied from the collapse into which he wjis fast sinking ; yet in the commencement they would have been as effectual ; so, mistake, would be gen«rally accredited for saving the patient, I say Providence did the work.
bloody flux.
If any one is permitted to die with all these prescription before them, it must be because a proper attention is no* given ; for God most undoubtedly works through the use of means, and is best pleased to see his children wear out, rather than h7-eak by coUigion of machinery on the way.
—Cholera morbus arises from a diseased condition of the bile, often brought on by over-indulgence with vegetables, espfcoially unripe fruits ; usually commencing with sickness and pain at the stomach, followed by the most excruciating pain and griping of the bowels, succeeded by vomiting and purging, which soon prostrate the patient. The person finds himself unavoidably drawn into a coil by the contrao* tion of' the muscles of the abdomen and extremities. Thirst very great, evacuations first tinged with bile, and finally, nearly ajl, very bilious.
Tbeatment. — The difficulty arises from the acidity of th# bile; then take saleratus, peppermint leaf, and rhubarb root puivjrized, of each a rounding tea-spoon, put into a cup, whi( h j'ou can cover, and pour upon them, boiling water ^ pt.; whfc-i nearly cold add a table-spoon of alcohol, or twice as muc.i brandy or other spirits. Dose — Two to 3 table-spoons ever ^ 20 to 30 minutes, as often and as long as the vomiting and ljQi!C ful purgations continue. If there should be long continued fftiii about the naval, use the "Injection" as mentioned under t'j/,(, head, in connection with the above treatment, and you will b?,(v, nothing to fear. If the first dose or two should be vomited repeat it immediately, until retained.
The above preparation ought to be made by every family, and kept on hand, by bottling ; for diseases of this character are as liable to come on in the night as at any other time ; then much time must be lost in making fires, or getting the articles together with which to make it.
2. Common Cholic. — There is a kind of cholic which some persons ure afflicted with, from their youth up, not attended with vomiting or purging. I was afflicted with it, trom my earliest recollection until I was over twenty years f>f age, sometimes two or three times, yearly.
In one of theae fits, about that age, a neighbor woman foame \i, and as soon as she found out what was the matter with me, , <»ne went out and pulled up a bunch of blue vervain, knocked Jie dirt from the roots, then cut them oflF and put a good handful of them into a basin, and poured boiling water upon them, And steeped for a short time, poured out a saucer of the tea and jave me to drink, asking no questions, but simply saying, " If you will drink this tea every day for a month, you will never nave cholic again as long as you live." I drank it, and in 15 minutes I was perfectly happy ; the transition from extreme paia to immediate and perfect relief, is too great to allow one to find words adequate to describe the diflferencc.
I continued its use as directed, and have not had a cholio pain since, nearly thirty years. I have told it to others, with the same result. It also forms a good tonic in agues, and after fevers, &c.
CARMINATIVES. — For the more common pains of th# stomach, arising from accumulating gas, in adults or child ren, the following preparation will be found very valuable, and much better than the plan of resorting to any of the opium mixtures for a constant practice, as many unwisely, or wickedly, do. See the remarks after " Godfrey's Cordial,'* and through this subject.
Compound spirits of lavender, spirits of camphor, and tincture of ginger, of each 1 oz. ; sulphuric ether and tiiicture of cayenne, of each i oz. Mix and keep tightly corked. Dose— For an adult, one tea-spoon every 15 minutes, until relieved ; for a child of 2 years, 5 drops ; and more or less, according to age and the severity of the pain.
3. CARMiNATrvE FOR Childuen.— Angelica and white rootSj. of each 4 oz. ; valerian and sculcap roots, with poppy heads, of each 2 ozs. ; sweet-flag root J oz. ; anise, dill, and fennel seed, with catmint leaves and flowers, motherwort and mace, of each 1 oz. ; castor and cochineal, of each i oz ; camphor gum 2 scruples, benzoic acid (called flower of benzoin) i oz. ; alcohol and water, of each 1 qt., or rum, or brandy 2 qts. ; loaf or cruslied sugar 1 lb. Pulverize all of the herbs and roots, moderately fine, and place in a suitable sized bottle, adding the spirits, or alcohol and water, and keep warm for a week, shaking once or twice every day; then filter or strain, and add the camphor and beueoin, shaking well ; now dissolve the sugar in another quart of water, by heat, and add to the spirit tincture, and all is complete. Dose. — For a very "oung child, from 3 to 5 drops ; if 1 year old, about 10 drops, aiid from that up to 1 teaspoon if 2 to 5 years old, &c. For adults, from 1 to 4 tea-spoons, according to the severity of the pain — to be taken in a cup of catmint or catnip tea for adults, and in a spoon of the same for children. It may be repeated every 2 to 6 hours, as needed.
i)er8piration, and produces refreshing sleep ; is also execlent for removing flatulency or wind cholic, and valuable in hysteria and other nervous affections, female debility, &c , in place of the opium anodynes.
8EIDL1TZ POWDEK&-GKNTJINK.— Rochelle salts 3 drs. ; bi -carbonate of soda 2 scruples ; put these into a blue paper, and put tartaric acid 35 grs. into a white paper. To use, pitt each
BUgar in with the acid, then pour together and drink.
This makes a very pleasant cathartic, and ought to be used more generally than it is, in place of more severe medicines. Families can buy 3 ozs. of the Rochelle-salts, and 1 oz. of the bi-carbonate of soda, and mix evenly together, using about 2 tea-spoons for 1 glass, and have the tartaric acid by itself, and use a little over ^ a tea-spoon of it for the other glass, with a table-spoon of sugar, all well dissolved, then pour together and drink while effervescing; and they will find this to do just as well as to bave them weighed out and put up in papers, which, cost three times as much, and do no better. Try it, as a child will take il with pleasure, as a nice beverage, and ask for more.
A lady once lost her life, thinking to have a little sport, by drinking one glass of this preparation, following it directly with the other ; the large amount of gas, disengaged, ruptured the stomach immediately.
DIPTHERIA — Dr. Phinney's Remedy, op Boston — Dr. Phinney, of Boston, furnishes the Journal of that city with a recipe for diptheria, which has recently been re-published by the Detroit Daily Advertiser^ containing 60 much sound sense, and so decidedly the best thing that I have ever seen recommended for it, that I cannot forbear giving it an insertion, and also ra^commend it as the dependence in that disease.
He says " the remedy on which I chiefly depend is the Actea Racemosa, or black snake-root, which is u.sed both locally as a gargle and taken internally.
As a gargle, 1 tea-spoon of the tincture is added to 2 tableBpoons of water, and gargled ei>ery hmir for tioenty-jmir hours, or till the progress of the disease is arrested; after which the interrals may be extended to an hour and a half, or more, as the symptoms may justify. In connection with the use of the gargle, or separately, the a<lult patient should take internally to the amount of two or three tea-spoons of the tincture in the course of twenty-four hours.
" In addition to the foregoing, give 10 drops of the muriated Uncture of iron 3 times In the 24 hours, and a powder from 3 to 5 giains of the chlorate of potash in the intervals.
Qcmbrane disappears usually within two days, and tfc« patient overcomes the malignant tendency of the disease. "The foregoing doses are for adults; for children they should of course be diminished according to age, &c. 14 will be observed that great importance is attached to the frequent use of the gargle — that is, every hour — in order to overcome the morbific tendency of disease by a constantly counteracting impression. In order to guard against a relapse, an occasional use of the remedies should be continued for several days after the removal of the m<5mbrane and subsidence of unpleasant symptoms. To complete the cure, a generous diet and other restorativca may be used as the intelligent practitioner shall direct."
CATHARTICS.— Vegetable Phtsic— Jalap and peppermint leaf, of each 1 oz. ; senna 2 ozs. ; pulverize all very finely, and sift through gauze, bottle it and keep corked. Dosk — Put a rounding tea-spoon of the powder and a heaping tea-spoon of BUgiir into a cup, and pour 3 or 4 spoons of boiling water upon thim ; when cool stir it up and drink all. The best time for taking it is in the morning, not taking breakfast, but drinking freely of corn-meal gruel. If it does not operate in 3 hours, repeat half the dose until a free operation is obtained.
Dr. Beach first brought this preparation, nearly in its preseii. proportions, to the notice of the Eclectic practitioners who have found it worthy of very great confidence, and L^pplicable in all cases where a general cathartic action is required. It may be made into syrup or pills, if preferred.
2. Indian Cathartic Pills.- -Aloes and gamboge, of each I oz. ; mandrake and blood-root, with g^ara mjTrh, of each i oz. ; gum camphor and cayenne, of each 1^ drs. ; ginger 4 ozs. ; all finely pulverized and thoroughly mixed, with thick mucilage (made by putting a little water upon equal quantities of ^lu arable and gum tragacanth,) into pill mass ; then formed mto common sized pills. Dose — Two to 4 pills, according to tha obustness of the patient.
Families should always have some of these cathartics, aa well as other remedies, in the house, to be prepared for accident, providence, or emergence, whichever you please to call it. They may be sugar-coated, as directed under that head, if desired.
TOOTHACHE AND NEURALGIA REMEDIES.— Magnetic Tooth Cordial and Pain Killer.— Best alcohol 1 oz. laudanum i oz. ; chloroform, liquid measiu'e, f oz. ; gum ctuQ
phor J oz. ; oil of elovea i dr. ; sulphuric ether f oz . ; and oil of Uvcnder 1 dr. If there is a nerve exposed this will quiet it. tLpply with lint. Rub also on the gums and upon the face agaiifst the tooth, freely.
In the case of an ulcerated tooth at Georgetown, Ohio, Mr. Jenkins, the proprietor of the " Jenkins' House," had been suffering for eight days, and I relieved him by bathing ths face with this preparation, using a sponge, for two or three minutes only, taking a tea-spoon or two into the mouth, for a minute or two, as it had broken upon the inside. The operation of the cordial was really mayical, according to old notions of cure.
I offered to sell a grocer a book, at Lawrenceburgh, Ind. He read until he saw the " Magnetic Tooth Cordial" menmentioned, then he says, "If you will cure mi/ toothache, I will buy one." I applied the cordial, it being late Saturday ftvening, and on Monday morning he was the first man ou hand for his book.
The Sheriff of Wayne Co., Ind., at Centerville, had been mffering three days of neuralgia, and I gave him such decided relief in one evening, with this cordial, that he gave me a three-dollar piece, with the remark, " Take whatever yuu please."
In passing from Conneatville, Pa., upon a canal boat, the cook, (who was wife of one of the steersmen,) was taken, after supper, with severe pain in the stomach. There being no peppermint on board, and as strange as it may appear, no spirits of any kind whatever; I was applied to as a physician to contrive something for her relief; I ran my mind over the articles I had with me, and could not hit upon any other so likely to benefit as the "Tooth Cordial," arguing in my mind that if good for pain where it could be applied to the spot externally, I could apply it to the point of paiu internally in this case, (the stomach,) as well. I gave her» tea-spoon of it in water, and waited five minutes without relief, but concluding to go " whole hog or none," I repeated the dose, and inside of the next five minutes she was perfectly cured. Her husband, the other steersman also, and one of the drivers, bought each a book, and the next week, in Erie, one of her neighbors bought another, upoo
equal success.
The cases are too numerous to mention more. I mention these to give confidence to purchasers, that all, who need it, will not fail to give it a trial. It is good for any local pain, wherever it can be applied. Pain will not long exist under ite use.
and apply as the other.
There are many persons who would prefer this last to the foregoing, from the presence of arnica ; and it is especially valuable as a liniment for bruises involving effusion of blood under the skin.
3. Neuraxgia — Internal Remedy. — Sal-ammoniac } dr., dissolve in water 1 oz. Dose — One table-spoon every 3 minutes, for 20 minutes, at the end of which time, if not before, the pain will have disappeared.
The foregoing is from a gentleman who had been long afflicted with the disease, who found no success with any other remedy. Instead of common water, the " Camphor Water" or " Mint AVater " might by some be preferred. The ammonia is a very diffusable stimulant, quicklj extending to the whole system, especially tending to the surface.
4. Keng of Oils, for Neuralgia and Kheumatism. — Burning fluid 1 pt. ; oils of cedar, hemlock, sassafras, and origanum, of each 2 ozs. ; carbonate of ammonia, pulverized, 1 oz. ; mix. Directions. — Apply freely to the nerve and gums, around the t(K)th ; and to the face, in neuralgic pains, by wetting brown paper and laying on the parts, not too long, for fear of blistering,— to the nerves of teeth by lint.
no relief.
5. Several years ago, I was stopping for a number of weeks at a hotel near Detroit ; whilst there, toothache was once made the subject of conversation, at which time the landlady, a Mrs. Wood, said she had been driven by it, to an extreme measure — no less than boiling wormwood herb is alcohol and taking a table-spoon of it into the mouth.
boiling liot, immediately closing the mouth, turning the head in such a way as to bring the alcohol into contact with all of the teeth, then spitting it out and taking the Becond immediately, in the same way, having the boiling kept up by sitting the tin containing it upon a shovel of hot coals, bringing it near the mouth. She said she never had toothache after it, nor did it injure the mouth in the least, but, for the moment, she thought her head had coW lapsed, or the heavens and earth come together. And iilthough the lady's appearance and deportment was such is to gain general esteem, I dared not try it or recommend >t to others. But during the last season I found a gentjeman who had tried the same thing, in the same way, except he took four spoons in his mouth at a time, and did aot observe to keep his mouth closed to prevent the contact of the air with the alcohol, the result of which was a ecalded mouth, yet a perfect cure of the pain and no recurrence of it for twelve years up to the time of conversation. And I do not now give the plan expecting it to become a general favorite, but more to show the severity of the pain, forcing patients to such extreme remedies. It would not be applicable only in cases where the pain was confined entirely to the teeth.
6. Horse-radish Eoot, bruised and bound upon the face, or other parts where pain is located, has been found very valuable for their relief. And I think it better than the leaf for drafts to the feet, or other parts.
7. Teeth — Extracting with little or no Pain. — Dr. Dunlap, a dentist of Chillicothe, 0., while filling a tooth for me, called my attention to the following recipe, given by a dental publication, to prevent pain in extracting teeth. He had used it. It will be found valuable for all who must have teeth extracted, for the feeling is sufficiently unpleasant even when all is done that can be for Js relief.
Tincture of aconite, chloroform, and alcolol of each 1 oz. , morphine 6 grs. Mix. Manner of Application. — Moisten two pledgets of cotton with the liquid and apply to the gums on each side of the tooth to be extracted, holding them to their place with pliers or some other convenient instrument for 5 to 15 minutes rubbing the gum freely inside and out.
My wife has had six teeth taken at a sitting, b it the lait two she wished to have out, she could not malcj up her mind to th« work until I promised her it should not hurt in the extraction, which I accomplished by accompanying her to Dr. Porter's dental office, of this city, and adminis tering chloroform in the usual way, just to the point ol nervous stimulation, or until its effects were felt over the whole system, at which time the teeth were tnken, not causing pain, she says, equal to toothache for one minute Not the slightest inconvenience was experienced from the effects of the chloroform. I consider this plar, and eo does Dr. Porter, far preferable to administering it untii entire stupefaction, by which many valuable lives have been lost.
8. Dektriricb which Removes Tartareous Adhesions, Arrests Decay, and Induces a ELealthy Action of thb GcMS. — Dissolve 1 oz. of borax in H pints of boiling water, and when a little cool, add 1 tea-spoon of the tincture of myrrh and I table-spoon of the spirits of camphor, and bottle for use. Directions.— At bedtime, wash out the mouth with water ; usin? a badger's hair brush (bristle brushes tear the gums and shoull never be used) ; then take a table-spoon of the dentrifice with as much warm water, and rub the teeth and gums well, each night until the end is attained.
It need not be used often, say once in three or foui months, as the teeth become black again, washing out quickly every time. "Without the washing after its use it would injure the teeth, with it, it never will. This blackneea is hard to remove, even with the brush and tooth powder.
10. Dr. Thompson, of Evansville, Ind., gives the above n twenty drop doses, three times daily, for laryngitis or bronchitis, taken in a little water, throwing it back past the teeth.
11. Tooth Powder — Excellent. — Take any quantity of finely pulverized chalk, and twice as much finely pulverized charcoal ; make very fine ; then add a very little suds made with Castile soap, and sufficient spirits of camphor to wet all u
I noticed the past season, a piece going the rounds of the papers, " That charcoal ought not to be used on the teeth." 1 will only add that a daughter of mine has used this powder over six years, and her teeth are very white, and no damage to the enamel, as yet. Six years would show up the evil, if death was in the 2>ot. Coal from basswood or other soft wood is the easiest pulverized.
ESSENCES. — Druggists* rules for making essences in to use one ounce of oil to one quart of alcohol, but many of them do not use more than half of that amount, whilst most j>f the peddlars do not have them made of over one-fourth ^hat strength. I would hardly set them away if presented I have always made them as follows :
Peppermint oil 1 oz. ; best alcohol 1 pt. And the same amount of any other oil for any other essences which you desire to make. Dose — A dose of this strength of essence will be only from 10 to 30 drops.
With most essences a man can drink a whole bottle without danger, or benefit. Peppermint is colored with tincture of tumeric, cinnamon with tincture of red sandal or sanders wood, and wintergreen with tincture of kino. There is no color, however, for essences, so natural as to put the green leaf of which the oil is made into the jar of essence, and let it remain over night, or about twelve hours ; then pour off, or filter if for sale. But if families are making for their own us<? they need not bother to color them at all. But many believe if they are high colored they are necessarily strong, but it has no effect upon the strength whatever, unless colored with the leaf or bark, as here recommended. Cinnamon bark docs in place of the leaf. See "Extracts."
TINCTURES. — In making any of the tinctures in com mon use. or in making any of the medicines called for ia this work, or in works generally, it is not only expected, but absolutely necessary, that the roots, leaves, barks, &c., should be dry, unless otherwise directed ; then :
add best alcohol i pt., keeping warm for from 4 to 6 days, or letting it stand 10 or 12 days without warmth, shaking once oi twice daily ; then filter or strain ; or it may stand upon the drega and be carefully poured off as needed.
With any person of common judgment, the foregoing directions are just as good as to take up forty times as much space by saying — take lobelia, herb and seed, 2 ozs. ; alcohol J pt. ; boiling water J pt., — then do the same thing*, over and over again, with every tincture which may be called for; or at least those who cannot go ahead with the foregoing instruction."', are not fit to handle medicines, at all ; so I leave the subject with those for whom the given information is sufficient.
In making compound tinctures, you can combine tho simple tinctures, or make them by putting the difTerent arti« cles into a bottle together, then use the alcohol and water it would require if you was making each tincture separately.
TETTER, RINGWORM, AND BARBER'S ITCH— To Cure. — Take the best Cuba cigars, smoke one a sufficient length of time to accumulate i or ^ inch of ashes upon the end of the cigar ; now wet the whole surface of the sore with the saliva fi'Om the mouth, then rub the ashes from the end of the cigar thoroughly into, and all over the sore ; do this three times a day, and inside of a week all will be smooth and well.
I speak from extensive experience ; half of one cigar cured myself when a barber would not undertake to shave me It is equally successful in tetters on other parts of the body, hands, &c *
spirits, however, it makes slaves of its devotees.
2. Narrow leaved (yellow) dock root, sliced and soaked in good vinegar, used as a wash, is highly recommended as a cure for tetter, or ring-worm.
BALSAMS.— Dr. R. W. Htjtchins' Indian Healing, pormKRiiY, Peckbam's Cough Balsam. — Clear, pale rosii^ 3 lbs., and melt it, adding spirits of turpentine 1 qt. ; balsam of tolu 1 oz t; balsam of fir 4 oza. ; oil of hemlock, origanum, with Venice turpentine, of each 1 oz. ; strained honey 4 ozs. ; mix well, and bottle. Dose— Six to 12 drops ; for a child of six, 3 to 5 drops, on a little sugar. The dose can be varied according to the ability of the stomach to bear it, and the necessity of the case.
keep warm for 5 days. i
Dr. Mitchel, of Pa., during his life, made great use of ^>is balsam, for cuts, bruises, abrasions, &c., and it will be found valuable for such purposes.
A.RTIFICIAL SKIN— For Burns, Bruises, Abrasions, &a P'iOOF Against AVater. — Take gun cotton and Venice turpentiue, equal parts of each, and dissolve them in 20 times as much eulphuric ether, dissolving the cotton fii"st, then adding the turpentine ; keep it corked tightly.
The object of the turpentine is to prevent pressure or pinching caused by evaporation of the ether when applied to a bruised surface. Water does not affect it, hence its value for cracked nipples, chapped hands, surface bruises, etc., etc.
DISCUTIENTS— To Scatter Swellings.— Tobacco and cicuta (water hemlock) leaves, of each 2 ozs. ; stramonium, (jinipsom) and solanam nigrum (garden night shade, sometimes erroneously called deadly night shade,) the leaves, and yellow dock root, of eacli 4 ozs. ; bitter-sweet, bark of the root, 3 ozs. Extract the strength by boiling with water, pressmg out, and re-boiling, straining and carefully boiling down to the consistence of an ointment, then add lard 18 ozs., and simmer together.
It will be used for stiff joints, sprains, bruises attended with swelling when the skin is unbroken, for cancerous lumps, scrofulous swellings, white swellings, rheumatic swellings, &c. It is one of the best discutients, or scatterers in use, keeping cancers back, often for months.
SMALL POX — To Prevent Pitting the Face. — A great discovery is reported to have recently been made by a Surgeon of the English army in China, to prevent pitting or marking the face. The mode of treatment is as follows :
When, in small pox, the preceding fever is at its height, and Just before the eruption appears, the chest is thoroughly rubbed with Croton Oil and Tartaremetic Ointment. This causes the whole of the eruption to appear on that part of the body to the relief of the rest. It also secures a full and complete eruption, and thus prevents the disease from attacking the internal organs. This is said to be now the established mode of treatment in the English army in China, by general orders, and ia regarded aa perfectly effectual.
It is a well known fact, that diseasa is most likely to make its attack upon the weakest parts, and especially upon places in the system which have been recently weakened by previous disease; hence, if an eruption (disease) is caui^ea by the application of croton oil mixed with a little of the Tartaremetic Ointment, there is every reason to believe that the eruption, in Small Pox, will locato upon that part instead of the face. The application should be made upon the breast, fore part of the thighs, &c., not to interfere wiib the posture upon the bed.
It has been suggested that a similar application will relieve whooping-cough, by drawing the irritation' from tho lungs ; if so, why will it not help to keep measles to the surface, especially when they have a tendency to the internal organs, called, striking in. It is worth a trial, in any of these cases. See " Causes of Inflammation," under the head of " Inflammation." ,
2. Common Swellings, to Reduce.— Tory-weed poundefJ nt as to mash it thoroughly and bound upon any common swelling, will very soon reduce the parts to their natural size.
This weed may be known from its annoyance to sheep raisers, as ic furnishes a small burr having a dent on one side of it. There are two species of it, but the burr of the other kind has no dent — is round. It will be found very valuable in rheumatisms attended with swellings.
WENS — To Cuke. — Dissolve copperas in water to makr> it very strong ; now take a pin, needl e, or sharp knife and prick, or cut the wen in about a dozen places, just sufficient to causf> it ti> bleed ; then wet it thoroughly with the copperas water, once daily.
This, followed for four weeks, cured a man residing within four miles of this city, who had six or eight of them, some of them on the head as large as a hen's egg. Tlie l>reparation is also valuable, as a wash, in erysipelas.
BLEEDINGS — Internal and External — Stypcto Balsam — For internal hemorrhage, or bleeding from the lungs, stomach, nose, and in excessive menstruation or bleeding from the womb, is made as follows :
Put sulphuric acid 2^^ drs. by weight, in a Wedgewood mortar and slowly add oi2 of turpentine 1 fluid dr., stirring it constantly with the pestle , then add slowly again, alcohol 1 fluid dr., ano
lOontinue to stir as long as any fumes arise from the miiture, thi>n bottle in glass, ground stoppered, bottles. It should be a cle«»r red color, like dark blood, but if made of poor materials n xlll be a pale, dirty red, and unfit for use. Dosk — To be given by putting 40 drops into a tea-cup and rubbing it thoroughly witn a tea-spoon of brown sugar, and then stir iu water until the cup tb nearly full, and drink immediately — repeat every hour for 3 or 4 iiours, but its use should be discontinued as soon as no more fresh blood appears. Age does not injure it, but a skim forms on the top which is to be broken through, using the medicine below i\.
This preparation was used for thirty years, with uniform duccess, by In-. Jas. Warren, before he gave it to the public ; since then, Dr. King, of Cincinnati, author of the Ecclectic Dispensatory, has spread it, through that work, and many lives have been saved by it. It acts by lessening the force of the circulation (sedative power,) as also by its astringent effects in contact with the bleeding vessels. And the probability is that no known remedy can be as safely depended upon for more speedy relief, or certainty of cure, especially for the lungs, stomach, or nose ; but for bleedings from the womb, or excessive menstruation, I feel to give preference to Prof. Piatt's treatment as shown in the recipe for " Uterine Hemorrhages." No relaxation from business ueed be required, unless the loss of blood makes it necessary, nor other treatment, except if blood has been swallowed, or if the bleeding is from the stomach, it would be well to give a mild cathartic. Bleeding f»-om the stomach will be distinguished from bleeding from the lungs by a sense of weight, or pain, and unaccompanied by cough, and discharged by vomiting, and iu larger quantities at a time than from the lungs. The blood will be darker also, and often mixed with particles of food.
Exercise in the open air is preferable to inactivity ; and if any symptoms of returning hemorrhage show themselves, oegin with the remedy without loss of time, and a reasoaable hope of cure may be expected.
8. External STVPTic Remedies. — Take a glazed earthcm vessel that will stand heat and put into it water 2^ pts. ; tincture af benzoin 2 ozs. ; alum J lb., and boil for 6 hours, replacing the water which evaporates iu boiling, by pouring in boiling water ao as not to stop the boiling process, constantly stirring. At the end of the 6 hours it is to be filtered or carefully strained and bottled, also in glass stoppered bottles. Apflication — Wet lint
and lay upon the wound, binding -with bandages tn prevent the thickened blood (coagula) from being removed from the mouths of the vessels, keeping them in place for 24 to 48 hours •will be ■ufflcient.
If any doubt is felt about this remedy, pour a few dropf of it into a vessel containing human blood — the larger the quantity of the styptic, the thicker will be the blood mas3, until it becomes black and thick. Pagliari was the first to introduce this preparation to public notice. — Eclectic Di^ pensatory.
3. Styptic Tincture — Extehnal Application. — Best brandy 3 ozs. ; finely scraped Castile soap 2 drs. ; potash 1 dr. ; mix all, and shake well when applied. Apply warm by putting lint up'ju the cut, wet with the mixture.
I have never had occasion to try either of the preparations, but if I do, it will be the " Balsam," or " External Styptic" first, and if they should fail I would try the " Tincture," for I feel that it must stop blood, but I also am certain that it would make a sore, aside from the cut ; yet, better have a sore than lose life, of course. These reraediea ire such, that a physician might pass a lifetime without ocsasion to use, but none the less important to know.
BRONCEOCEI.E— Enlauged Neck— To Curb.— Iodide of potassium (often called hydriodateofpotash,)2 drs. ; iodine 1 dr. ; water 2 \ ozs. ; mix and shake a few minutes and pour a little into a vial for internal use. Dose — Five to 10 dr(5ps before each meal, to be talcen in a little water. External Application. — "With a feadier wet the enlarged neck, from the other bottle, night and morning, until well.
It will cause the scarf skin to peel oflF several times bofore the cure is perlect, leaving it tender, but do not omit the application more than one day at most, and you may rest assured of a cure, if a cure can be performed by any means whatever ; many cures have been performed by it, and there is no medicine yet discovered which has proved one-hundreth part as successful.
2. But if you are willing to be longer in performing the cu'-*, to avoid the soreness, dissolve the same articles in alcohol 1 pt,, and use the same way, as above described, {i. e.) both internal and external.
PAIN KILLER— Said to bk Pebry Davis'.— Alcohol 1 qL ; gum guaiac 1 oz. ; gums myrrh and camphor, and cayenne pi;lverized, of each J oz. Mix. Shake occasionally for a week oe
10 days and filter or let settle for use. Apply freely to surface pains, or it may be taken iu tea-spoon doses for internal pains, and repeat according to necessities.
If any one can tell it from its namesake, by its looks or actions, we will then acknowledge that the old minister, from whom it was obtained, was greatly deceived, although ha was perfectly familiar for a long time with Mr. Davis, and his mode of preparing the pain-killer.
POISONS — Antidote. — ^When it becomes known that a p<»jtwi has been swallowed, stir salt and gi-ound mustard, of each a, heaping tea-spoon, into a glass of water, and have it drank immediately. It is the quickest emetic known.
It should vomit in one minute. Then give the whites of two or three eggs in a cup or two of the strongest coffee. If no coffee, swallow the egg in sweet-cream, and if no cream sweet-milk, if neither, down with the egg.
I have used the mustard, with success, in the case of my own child, which had swallowed a " Quarter " beyond the reach of the finger, but remaining in the throat, which, to all appearances, would have soon suffocated him. I first took " granny's plan" of turning the head down and patting on the back j failing in this, I mixed a heaping tea-spoon of mustard in sufficient water to admit its being swallowed readily ; and in a minute we had the quarter, dinner, and all ; without it, we should have had no child.
1 knew the mustard to work well once upon about twenty metk in a boat-yard, on Beile River, Newport, Mich. 1 had been furnishing them with " Switchel" at twenty cents per bucket, made by putting about a pound of sugar, a quart of vinegar, and two or three table-spoons of ginger to the bucket of water, with a lump of ice. An old man, also in the grocery business, offered to give it to them at eighteen pence per bucket, but, by some mistake, he put in mustard instead of gmger. They had a general vomit, which maoft them think that Cholera had come with tba horrors of " Thirty-Two," but as the downward effects were not experienced, it passed off with great amusement, safely establishing my custom at the twenty cents per bucket.
INFLAMMATOllY DISEASES— Description.— Before I attempt to speak of the inflammation of particular organs, I shall make a few remarks upon the subject in gen
eral,'whicli will throw* out the necessary light for those not already informed ; and I should be glad to extend my treatment to all of the particular organs of the body, but the limits of the work only allows me to speak of Pleurisy, Inflammation of the Lungs, &c. j yet, Eclectic ideas of inflammation are such, that if wc can, successfully, treat inflammation in one part of the system, (body,) we can, with but little modification, succeed with it in all of its forms : And my general remarks shall be of such a nature as to enabk any judicious person to, successfully, combat with inflammations in every part of the system. Then :
First. — Inflammation is, generally, attended with pain^ increased heat, redness, ar d swelling. Some, or all of these signs alwai/s accompanyii g it, according to the stmciure of the organ afiected.
Second. — The more loose the structure of the organ, the less severe will be the pain ; and the character of the structure also modifies the character of the pain. In mucau$ membranes, it is burning or stinging. In serous membranw it is lancinating, and most usually very sharp and cutting In fibrous structures, it is dull, aching, and gnawing. In nervous structures, it is quick, jumping, and most Tisuaily excruciatingly severe ; and in nearly all structures more (^ less soreness is soon present.
Third. — To make the foregoing information of value, it becomes necessary to know the structure of the various parts of the system. Although the ultimate portions of muscle or flesh, as usually called, is fibrous, yet, there is a loose cellular structure blended with it, which fills up afld rounds the form to its graceful beauty — hence, here, w« have more swelling, and less severity of pain. With tha rose, or red of the lips, commences the mucous membrane, which forms the lining coat of the mouth, stomach, &c., through the whole alimentary canal, also lining the urethra, bladder, uret^.rs, vagina, womb, fallopian tubes, &c., hence the heat always felt in inflammation of these organs The whole internal surface of the cavity of the body is lined by a scrolls membrane, which is also reflected or folded upoa the lungs— here called pleura, (the side,) hence pleurisy, (inflammation of the pleura or side,) and also folded upon
feie upper side of the diaphragm j the diaphragm forming a partition between the upper and lower portions of the cavity of the body, the uppxjr portion containing the lungs, teart, large blood vessels, &c., called the chest, more commonly the breast — the lower portion containing the stomach, liver, kidneys, intestines, bladder, &c., called the abdomt<i — more commonly the bowels. The sides of the abdomen are covered with a continuation of this serous membrane, which is also reflected upon the lower side of the diaphragm, liver, stomach, small and large intestines, bladder, &c., — here called peritoneum, (to extend around) in all places it secretes (furnishes) a moistening fluid enabling one organ of the body to move upon itself or other organs without friction. This serous membrane is thin, but very firm, hence the sharpness of the pain when it is inflamed, as it cannot yield to the pressure of the accumulating blood.
Fourth.- -The ligaments or bands which bind the different parts of the body together at the joints, and the gracefully contracted ends of the muscles (called tendons) which pass the joint, attaching themselves to the next bone above, or below, and the wristlet-like bands which are clasped around the joints through which these tendons play, as over a puUy, when the joint is bent, are all of a fibrous construction, hence the grinding or gnawing pains of rheumatism (inflammations), and injuries of, or near joints; and it also accounts for that kind of pain in the latter stages of intestmal inflammations, as the stomach, intestines, &c., are composed of three coats, the external, serous, — middle fibrous, internjil, mucous; and when inflammation of the external, or internal ; coats are long continued, it generally involves the middle — fibrous layer.
Fifth. — Thrs greatest portion of the substance of the lungs is of fibrous tissue, consequently, dull or obtuse pain only, is experienced when inflamed.
Lastly. — The nervous system, although of a fihrout character is so indescribably fine in its structure, that, like the telegraph wire, as soon as touched, it answers with a bound, to the <;all — quick as thought, whether pain or pleasare, jimiping, bounding, it goes to the grand citadel (the brain) which overlooks the welfare of the whole temple.
In general, the intensity of the pain attending inflammations will surely indicate the violence of the febrile (sympathetic) reaction ; for instance, in inflammation of the bronchial tubes, the pain is not very severe, consequently not much fever, (reaction) ; but in inflammation of the pleura (pleurisy) the pain is very severe, conse quently the febrilo reaction exceedingly great.
Causes of Inflammation. — In health, the blood carried evenly, in proportion to the size of the blood vessels, to every part of the body. And the vessels (arteries and veins) are proportioned in size to the necessity of the system for vitality, nutrition, and reparation. AVhatever it may be that causes the blood to recede from the surface, or any considerable portion of it, will cause inflammation of the weakest portion of the system ; and whatever will draw the blood unduly to any part of the system, will cause inflammation of that part, — for instance, cold drives the blood from the surface, consequently, if sufliciently long continued, the internal organ least able to bear the accumulation of blood upon it will be excited to inflammation — a blow upon any part, if sufliciently severe, will cause inflammation of the injured part. Also mustard poultices, drafts to the feet, &c., hence the propriety of their proper use to draw the blood away from internal organs which are inflamed. A check of perspiration is, especially, liable to excite inflammation, and that in proportion to the degree of heat producing the perspiration and the length of time which the person may bo exposed to the cold. The objeet of knowing the cause of disease is to avoid sufiering from disease, by keeping clear of its cause ; or thereby to know what remedy to apply foi itB cure or relief.
There is a class of persons who claim that ca«ses will have bheir legitimate effects, ph/siccd or moral ; physicians know that it is absurd physically ; that is, when philosophically and scientifically combated with, — for instance, a person is exposed to cold ; the blood is driven in upon the internal organs, and the one which is the least able to bear the pressure gives way before the invading enemy, and an inflammation is the result J which, if left to itself, will terminate in 'leath J but heat and moisture are applied to the constringed irface — the blood is brought bacw and "held there, and «
the cause is obviated or avoided.
Then why should it be thought impossible with Xjod that a moral remedy should be provided against moral evils ? Thanks be to God, it has been provided to the willing and obedient, through our Lord Jesus Christ, but only to the willing and obedient, morally as well as physically, for if a person will not permit a proper course to be pursued to overcome tne consequences arising to his body from cold, he must suffer, not only the inflammation to go on, but also guilt ol mind for neglecting his known duty. The same is true in either point of view, only it looks so curious that there should be those who can reason of physical things, but utterly refuse to give up their moral blindness ; the conV3quences be upou their own heads.
Just in proportion to the susceptibility of an organ to tak« oa diseased action, is the danger of exposure ; for example if a person has had a previous attack of pleurisy, or inflammation of the lungs, those organs, or the one which has been v^iseased, will be almost certain to be again prostrated, usually called relapse ; which is in most cases, ten times more severe than the first attack ; then be very careful about exposures when just getting better from these, or other disease.
Inflammation terminates by resohition, effiision, s^ippuration, or mortification. By resolution, is meant that the parts return to their natural condition ; by effusion, that blood may be thrown out from the soft parts, or from mucous membranes, — that lymph, or serum, a colorless part of the blood may be thrown out by seraus membranes, which often form adhesions, preventing the after motions of the affected parts — and here what wisdom is brought to light, in the fact that whatever is thrown out from the mucus surface never, or at least very seldom adhere, or grow up ; if it did, anj part of the alimentary canal from the mouth to the stomach, and so on through the intestines, would be constantly adhering ; so,also of the lungs ', for these various organs are more frequently affected by inflammations than any other parts of the body — by suppuration, when abscesses are formed containing pus (matter,) or this may take place upon the surface, when it is usually called canker, or corroding ulcers, cancers, &c. ; by gangrene, (mortification,) when death of
the parte take place ; in this case, if the part is sufflcicntlj extensive, or if it is an internal part, death of the whole body, if not relieved, is the result.
The methods of inflammatory termination is believed to result from the grade of inflammation — for instance, at the circumference of a boil, the inflammation is weak, serum is thrown out ; near the centre, where the inflammation i" a little higher, lymph is poured out and adhesion takes place ; — next pus — at the centre, viortifiction and consequent sloughing takes place.
In boils, the tendency is to suppuration ; in carbuncles, the tendency is to mortification; but in rheumatism, mumps, &c,, there is a strong tendency to resolution ; and it is often very difficult to avoid these natural terminations.
The five different tissues of the body also modify the inflammation according to the tissue inflamed, viz : the cellular (fleshy) tissue, is characterized by great swelling, throbbing pain, and by its suppurating in cavities — not spreading all over that tissue. Inflammation of the serous tissue, has sharp lancinating pain, scarcely any swelling, but much reaction (fever), throws out lymph, and is very liable to form adhesion — not likely to terminate in mortification, except in peritonitis (inflammation of the lining membrane of the abdominal cavity), which sometimes terminates thus in a few hours, showing the necessity of immediate action. Inflammation of the mucous tissue, is characteriz(jd by burning heat , or stinging pain (hence the heat of the stomach, bowels, &c.) — without swelling, not much febrile re« action, and never terminates in resolution (health) without a copious discharge of muciLS, as from the nose and lungs, m colds, catarrhs, coughs, <fec. Inflammation of the dermoid (skin) tissue, as in erysipelas, is characterized by burning pain — spreads irregularly over the suaface, forming blistera containing a yellowish serum, but never forms adhesions, nor suppurates in cavities, but upon the surface. Inflammation of the fibrous tissue, or rheumatic inflammation, ia characterized by severe aching or gnawing pain — is not liable to terminate in suppuration nor mortification — nearly always throwing out a gelatinous serum, often causing stifle joints, or deppsiting earthy matter, as in gout — is peculiarly Hable to change its place, being very dangerous i/ it change
mkdiojll department. 201
« any of the vital organs, as the brain, heart, stomach, &c., a a in the acute form the febrile reaction is usually quite severe. Internal inflammation will be known by the constant pain of the inflamed part, by the presence of fever, which does not generally attend a spasmodic or nervous pain, and by the position chosen by the patient, to avoid pressuie upon the afilicted organs.
Inflammation is known under two heads, acute and chnmic The first is generally rapid and violent in its course and characteristics. The laet is usually the result of the first, — ^is more slow and less dangerous in its consequences.
Treatment. — Sound philosophy (Eclecticism) teaches, that if cold has driven the blood (consequently the heat) fiom tL« surface, heat will draw it back; and thus relieve the internal engorgements (over-full organs) and if held there, suficiently long, entirely cure the difficulty (inflammation) , upon the same ground, if a person is cold, warm him ; if wet and cold, warm and dry him ; if hot, cool him ; if dry and hot, wet and cool him — equalize the circulation and pain or disease cannot exist.
The foregoing remarks must suflice for general directions j but the following special application to pZewmy and inflammation of the lungs shall be sufflcienlly explicit to enable all to make their general applications.
2. Pleurisy. — Pleurisy is an inflammation of the seroui tbembrane inveloping (covering) the lungs, which is also reflected (folded) upon the parieties (sides or walls) of the chest, (but I trust all will make themselves familiar with the description of " Inflammation in General," before they proceed with the study of pleurisy,) attended with sharp lancinating pain in the side, diflScult breathing, fever, with a quick, full, and hard pulse, usually commencing with a chill. Jn many cases the inflammation, consequently the pain, is confined to one point, most commonly about the short ribs ; but often gradually extends towards the shoulder and forward part of the breast ; the pain increasing, and often becoming veiy violent. It may not, but usually, is attended with cough, and the expectoration ia seldom mixed with blood, or very fr^'e, but rather of a glairy or mucous character. As the disease advances, the pain'ia compared to a stab with a sharp instrument, full breathing
not being indulged, from its increasing the difficulty ; the cough also aggravates the pain; great prostration of strength, the countenance expressing awxiety and suffering. The breathing is short, hurried, and catching, to avoid increase of pain J in some cases, the cough is only sligltt. It may be complicated with inflammation of the lungs, or bronchial tubes, and if so complicated, the expectoration will b* mixed or streaked with blood. Y^et it makes but very little difference, as the treatment is nearly the same — with th» exception of expectorants, quite the same; although expectorants are not amiss in pleurisy, but absolutely neces sary in inflammation of the lungs. Even Mackintosh, of the " Kegulars," says : " It must be recollected that pneumonia " (iuflammation of the lungs) " and pleuritis " (pleurisy) " Frequently co-exist " (exist together); " But neither is that circumstance of much consequence, being both inflammatory diseases, and requiring the same genera* remedies." But there I stop with hijn, for I cannot go tho bleeding, calomel, and antimony. I have quoted his words to satisfy the people that the " RegUiars " acknowledge the necessity of a similar treatment in all inflammatory diseases, the difference between the two branches of the profession, existing only in the remedies \ised. i
Causes op Pleurisy. — Cold, long applied, constrinpes (makes smaller) the capillaries (hair-like blood-vessels) which cover as a net-work the whole surface, impairing- the circulation, driving the blood internally, causing congestion (an unnatural accumulation of blood) upon the pleura, lience pleurisy. Exposures to rains, especially cold rainis, cold, wet feet, recession (striking in) of measles, gcarler. /ever, rheumatism, &c., often cause inflammation of ttau character.
Indications. — Relax the whole surface, whioii removes the obstructions — restore, and maintain, an equal oirculation, and the work is accomplished. The temperftttire of the surface and extremities is much diminished, enowing tnat the blood has receded (gone) to the internal, diseased, organs, the temperature of which is much incrcsused ; for with the blood goes the vitality (heat) of the body. This condition of the system clearly indicates the treatment, viz : the application of heat to the surface in stich a way as to b«
mg on her own work, in her own way.
TREATifENT. — It has been found that the quickest and least troublesome way in which heat could be applied to the whole surface, is by means of burning alcohol, formerly called a "Rum sweat," because rum was stronger than at present, and more pl«nty than alcohol ; but now alcohol is the most plenty, and much the strongest and cheapest. It should alw^ays be in the house (the 98 per cent.) ready for use . as described under the head of " Sweating with Burning Alcohol," (which see), or if it is day time, and fires are burning, you can give the vapor-bathsweat, by placing a pan, half or two-thirds full of hot water, under the chair, having a comforter around you ; then putting into it occasionally a hot stone or brick, until a free perspiration is i)roduced and held for from 15 to 30 minutes, according to the severity of the case ; and if this is commenced as soon as the attack is fairly settled upon the patient, in not more than one case out of ten will it be necessary to do anything more ; but if fairly established, or if of a day or two's standing, then, at the same time you are administering the sweat, place the patient's feet in water as hot as it can be borne ; have also a strong tea made of equal parts of pleurisy-root and catnip, (this root is also called white root — Doctors call it asclepias tuberosa)— into a mucer of this hot tea put 2 tea-spoons of the " Sweating Drops," irinking all at one time, repeating the dose every hour for 5 or 'i hours, using only 1 tea-spoon of the drops at other times, ex;ept the first, giving the tea freely once or tw^ce between doses. A.S soon as the sweating is over, place the patient comfortably m bed so as to keep up the perspiration from 6 to 12 hours, or antil the pain and uneasiness yield to the treatment. If necessary, after the patient takes the bed, ])lace bottles of hot water to I he feet and along the sides, or hot bricks, or stones wrapped with flannel wet with vinegar, to help keep up the perspiration; Muhtard may also be placed over the seat of pain, and upon the Feet also rubbing the arms and legs with dry flannel, which very mu( h aids the process when the attack is severe. If the pain ymknues severe, and perspiration is hard to maintain, steep cayenne, or common red peppers in spirits and rub the whole surface with it, well and long, and I will assure the blood to come out soon and see what is going on externally. Keep the patient well covered all the time, and avoid drafts of cold air. As tha painful symptoms begin to subside, the doses of medicine may be lessened, and the time between doses lengthened, until tha disease is fairly under control ; then administer a dose of tha "Ve[retable Physic," or some other cathartic, if preferred, or if that is not at hand, this course may be repeated or modified to meet returning or changing symptoms.
Wetting .he surface daily, with alcohol and water, equal pai'ts, will be found an excellent assistant in treating, any diseafaC, especially, internal iiiflmmatious, as Pleurisy, Inflammation of the Lunge, Conauicpl<;n, Bronchi ts, &c., &c.
The pleurisy root is almost a specific m pleurisy or in flammatlon of the lungs; no other known root or herb u equal to it for producing and keeping up perspiration (dmggists usually keep it,) but if it cannot be got, pennyroyal, eage, &c., or one of the minta, must be used in its j>«ace. The only objection to the foregoing treatment is tl«i«, tiH» Doctors say :
Ueigh ! I guess he wasn't very giok ; For see ! he's round in " double quick" ; But alopath holds 'em for weeks, six or seven, Whea bleeding, calomel, and antimony are given.
To illustrate : I awoke one night with severe paj» in tho left side (I had heen exposed to cold during the aJTiemoon,) could not move or draw a full breath without very much increasing the difficulty; the night was cold and fires all down ; I studied my symptoms for a few minutes, and also reflected upon the length of time which must elapse, if I waited for fires to be built ; then awoke my wifb, saying do :\ot be frightened, I have an attack of Pleurisy ; you will get me a comforter, saucer, and the alcohol, and return to bed without disturbing any one ; with persuasion, or almost compulsion, she did so ; for she desired to" build a fire and make a more thorough work of it ; but I had made up my mind and resolved to carry out the experiment upon myself, and now had the only chance. I arose and poured the saucer nearly full of alcohol, and set it on fire ; wrapping the comforter around me, I sat down upon the chair, over It, and continued to sit until the alcohol was all burned out, Hinl I in a most profuse perspiration ; the pain and difficult breathing having nearly all subsided ; I then returned to bed, the perspiration continuing for some consifi^rable longer, by retaining the comforter around me to avoid checking it as I returned to bed, during which time I ^M^ain fell asleep. When I awoke in the morning I could just realize a little pain, or rather uneasiness, upon taking a fall breath, but did nothing more, being very careful abont exposure however, through the day ; but at bed time I took another alcohol sweat, and that was the last of the pleurisy.
Again : Mr. , a medical student rooming in the
same house where I lived, awoke in the night, attacked with pleurisy, the same as myself, after exposure ; but aa he was attending the lectures of alopathic professor*. >*f
course, he must have one of them to attend him ; one was ealicd, three pints of blood were taken, calomel and antimony wore freely given ; and in about three or four days the disease gave way to time, or the treatment ; but a calomel-Diarrhea set in, and came very near terminating his life, and kept him from college and his studies over six weeks; and he said if he was ever calomelized again, he would prosecute the doer to the end of his life ; uut he graduated in that school of medicine, and no doubt is now expecting to go and do the same thing. Choose ye your servant. Shall he be reason, with common-sense rcsuils, oi shall he be silver-slippered fashion, with hio he<h-dtstroying policy? It need not oe ars'i'od thau theae woic not parallel cases, for I had the pleurisy when young, &Zid was treated in the fashionable style, and was constantly liable to, and had frequent attacks of it during my earlier life.
In chronic cases, which sometimes occur, and frequently under other treatment, it will be necessary, not only to use the foregoing treatment, but to add to it an emetic about once a week, alternating with the sweating process, with much external friction, occasionally, with the pepper and spirits to hold the blood to the surface.
Since the first publication of the foregoing, I have seen a statement going the rounds of the " Papers," that a bad case of burning had taken place in N. Y., by the alcohol process of sweating, calling it 7i€io ; but it has been in use more than /orti/ years ; I have used it, I speak safely, more than a hundred times, and never before heard of its injuring any one ; but still it is possible that some accident may have occurred in its use, or that some one has undertaken it who was not capable of prescribing j but if calomel could claim one year's use under its most accomplished prescribers with only one case of injury^ I would say, let it be continued , but in place of one, it is hundreds ; farther comment ia unnecessary.
But, those who prefer, or from the absence of alcohol, or other necessities, can take " grandmother's plan," i. «., place the feet into hot water, and drink freely of pennyroyal, sage, or other hot teas, for fifteen to twenty minutes ; then get into bed, continuing the teas for a short time, remaining in bed for a few hours ; which, if" commenced soon aft«r the
attack of colds, or even more severe diseases, will, in nine out of ten cases, not only relieve, bat prevent days, perhaps weeks, of inconvenience and suffering.
lungs, you will find explanations under the next head,
3. Inflammation of the Lukgs— Is usually, by physicians, called Pneumonia, from the Greek, Pneumon, the Lungs. It may involve the whole lung, on one or both sides, but is more generally confined to one side, and to the lower portion, than to the whole lung.
Causes. — Exposure to cold, wet, cold feet, drafts of air, especially if in a perspiration, recession of eruptive diseases, &c., and consequently more liable to come on in the winter, or cold wet changes of spring, than at any other time; and upon those whose lungs are debilitated by previous attacks, or are predisposed to, or actuallysuffering under disease.
Symptoms. — Inflammation of the Lungs, like other diseases of an inflammatory character, nearly always commences with a chill, soon followed by fever, more or less violent, according to which, the severity of the case may be somewhat predetermined, unless of a congestive character; in which case, instead of a hot and fevered surface, there will be a cold, clammy feel to the hand, as well as unpleasant to the patient. There will be difficulty in taking full breaths, as well as an increased number of breaths to the minute, which in healthy persons is generally about twenty. Dull pain, with a tightness of the chest, short and perpetual hackmg cough, scanty expectoration, which is tough, and sticks to the vessel used as a spittoon, and is more or less streaked with blood, or more like iron-rust in color, and may have so much blood in it as to make it a brighter red. The pulse vi variable, so much so that but little confidence can be placed in it. The tongue soon becomes dry and dark; but a dry and glossy tongue, with early delirium, are considered daag<^rous symptoms, that is, under " Old School treatment." But with our rational treatment we very seldom have a fat:J termination, yet it is occasional, and really wonderful that it la not more frequent, when we take into account the neglect o| some physicians and imprudence of many patients.
Indications. — As the blood has receded from the surf*\3e and centered upon the lungs ; the indications are to return it to its original vessels, by judiciously applying heaii and moisture, which is sure to relax their constringed condition, instead of cutting a hole and letting it run out (bleeding), which prostrates the patient and retards his recovery.
lliEATMENT. — ^Thc treatment of Inflammation of the Lungs in recent cases, will be, at first, the same as for " Pleurisy," that is, to ptoduce-free perspiration — soak the feet in hot water while admmistering the " Alcohol Sweat," or Vapor Bath, as there directed, with the white-root tea and " Sweating Drops," for several hours, with bottles of hot water or hot ])ricks to the feet and Bides, mustard-drafts to the feet also, as they can be borne ; and after 6 or 8 hours, the •' Vegetable," or other cathartic should be administered, and great care not to expose the patient to drafts of ail during its oiieration, especially if in perspiration. If this course is faithfully persevered in, it will call the blood to the Burface — prevent congestion of the lungs (unnatural accumidation of blood) — lessen the fever — ease the pain and aid expectoration. But if the expectoration becomes difficult, and the disease should not seem to yield in from 8 to 12 hours at farthest, or by the time the cathartic has freely operated, then, or soon after, give the " Eclectic," or " Lobelia-seed Emetic," as directed under that head ; and if called to a case wliich is already confirmed, it is best to begin with the emetic, then follow up as above directed in recent cases. An expectorant, in confirmed (established) cases will be needed— let it be composed of tincture of lobelia 1 oz. ; tincture of ipecac i oz. ; tincture of blood-root i oz. ; simple syrup or molasses 2 ozs. ; mix. Dose — One teaspoon every 2 hours, alternately with the white-root tea and " Sweating Drops," except the first dose may be 2 tea-spoons. The case must then be watched carefully ; and any part or all of the treatment may be repeated, lessened, increased, or modified, to suit returning or remaining symptoms.
Persons having this book in the house, and being governed by it, having also the leading medicines on hand ; and commencing with this disease, or inflammation of any other organs, modifying the treatment by common sense, according to the remarks on " General Inflammation," will aot have to repeat the course in one case out of ten.
In inflammations of the stomach, known by heat, according to the degree of the inflammation, drinks of slipperyelm water, or mucilage of gum arable, &c., may be freely taken ; and in inflammation of other organs, other modifications will be required ; as for Dysentery, which is an in-
freely used, as also the perspiring processes, in all cases.
In chronic inflammation, the emetic should be given once a week ; and some other time during the week, the sweating should be gone through also, with dry frictions to the whole surface, by means of a coarse towel, for fifteen to twenty minutes each time, twice daily ; and if the feet are habitually cold, wash them in cold water and wipe them dry^, at bed time, then rub tliem with a coasse cloth or the drj' hand until they are perfectly warm and comfortable ; and it may be expected that these long standing eases will soon yield to this raiumai course. »
Female Debility and Irregularities. — ^It is a self evident fact "that the finer the Avork, and the more complicated a piece of machiner}', the more liable is it to become deranged, or out of order ; and the more skillful must be the mechanic who undertakes to make any necessary repairs.
Upon this consideration I argue that the system of the female is the finer and more complicated, having to perform a ^double work, (child-bearing,) yet confined to the same or less dimensions than the male. And to perform this dovMe function of sustaining her own life, and giving life to her species, it becomes necessary in the wisdom of God to give her such a peculiar formation, that between the ages of fifteen and forty-five, or the child-bearing period., she should have a sanguineous, monthly flow, called by various names, as, monthly periods, menstruation, menses, catamenia, courses, &c., &c.
Why it should have been so arranged, or necessary, none can tell. We are left to deal with the simple fact; and it would be just as wise in us to say that it was not so, as to say there was no one \y\\o plmned it, because we cannot see and fully understand the reason why it is so. This flow varies in amount from one to three, four, or five ounces, lasting from three to four or five days only, when usual health is enjoyed. And as this book will fall into the hands of very many families who will have no other medical work for reference upon this subject, it Avill not be amiss for me to give the necessary instructions here, that all may be able to qualify themselves to meet the exigencies (demand) of all cases. A day or two previous to the commencement of these periods, for the first lime, an uneasiness often amounting to pain, in the parts, is felt, with sense of heaviness also in the womb — lying in the lower part of the abdomen.
Some females are very nervous at these periods, others have a flushed face accompanied with d'zziness and headache sickness at the stomach, &c. In young girls these new feelings produce uneasiness, for want of knowledge as to their cause and result, and should lead them to seek maternal
advice and counsel, unless they have some book of this kind which explains the whole matter. And it would certainly be advisable, in all cases, for girls to not only seek such advice from the mother, or lady with whom they may be living, but be guided by it also. And although, with many ^irls, there may be uneasiness in the mammae, often amountmg to real pain, yet, no real danger need be apprehended ; for these unpleasant sensations will continue, and increase in severity, until in healthy young females there will be what is knows as a "sAodf," which will afford immediate relief, not from the quantity of the flow, at the first few periods, tut from the fact that the organs peculiar to the female have accomplished their mj-sterious work. Ordinarily these periods begin at about fifteen years of age, some earlier or later even as much as a year and sometimes more. With girls wlio take an active part fc the labors of the house, freely romping, playing, &c., their health and strength becoming fully developed thereby, these periods come on a little earlier, and are more healthy and regular.
Allow me here to give a word of caution about taking cold at this period. It is very dangerous. I knew a young girl, who had not been instructed by her mother upon this subject, to be so afraid of being found witli this show upon her apparel which she did not know the meaning of, that she went to a brook and washed herself and clothes — took cold, and immediately became insane — remaining so as long as I knew her. Any mother who so neglects her duty to her child, in not explaining these things, nor by putting a work of this kind into her hands, runs the risk of injury to her daughter that may never be remedied, even with the best treatment, after the harm is done.
After this flow takes place, the unpleasant feelings usually subside, and the health again becomes good for the month, when all of the foregoing sensations recur again, with a larger flow and longer continued, recurring every four weeks, and is then called menses «&c., &c.
deranged in various ways.
It may be partially suppressed or entirely stopped, called, amerwrrliea, — it may become painful or imperfect, dysmenorrlisa, — it may be very free or excessive, menorrlMgia, (like hemorrhage, for the treatment of which see recipe for Uterine Hemorrhage in another part of the book), — or, it may be irregular in its recurrence and duration, or a continual glairy flow which indicates an inflammation of the parts, leiwarrhea.
soon produce general debility.
Causes. — The female organism is such that what affects tho general system of the male, much more frequently affects the organs peculiar to her system only. No reason can be given for it except the wisdom of the Creator, and the necessities of her construction. But this debility and irregularity are so interwoven together that what causes one must necessarily affect the other.
In the good old grandmother-days, when girls helped with the work of the household, warm but loose clothing, plain food, good thick-soled shoes, and absence of novels, to excite the passions, &c., such a thing as a feeble, debilitated woman or girl wa^ seldom known ; but now, sedentary habits, stimulating food, every conceivable unphysiological stj^c of dress, paper-soled shoes, checking perspiration, excitable reading, repeated colds by exposure going to and from parties, thinly clad, standing by the gate talking with supposed friends (real enemies) when they ought to be bj' the fire or in bed, all tend to general debility ; and the real wonder is that there is not more debility than there is.
Symptoms. — The very word debility, shows plainly the leading symptom, weakness. Slie appears pale, especially about the lips, nose, &c., with a bluish circle about the eyes, which appear rather sunken, she feels dull, languid, and drowsy, stomach out of order, nausea, often with fluttering about the heart ; the nervous system sometimes becoming so much involved as to bring on fits of despondency leading many to commit suicide. The feet and limbs frequently become swollen, restless in sleep, often craving unnatural food, as clay, soft stones, &c. There may also be a sensation of bearing down, or even falling of the womb, as it is called, (prolapsus uteri) which is much the most common among the married. The bowels are usually costive, often griping pains which cause much suffering. Pains in the head and back also ; but instead of being looked upon as unfavorable, they rather show that nature is trying to accomplish her work, and needs the assistance of rational remedies.
It is not to be supposed that every patient will experience all of these symptoms, at one time, or all of tlie time ; but they commence as pointed out, and if allowed to go on without proper correction, they will increase in severity until they may be all experienced in a greater or less degree.
Indications. — The symptoms indicate (point out) the treatment, that is, if there is debility, tonics are required ; paleness shows that the blood has become deficient iu iron ; and the
softness of the flesh indicates that a more nutritious diet 13 needed. The dullness and drowsy languidness indicate the necessity of out-door, active exercise. Travel, or, agreeable home company, to ramble over hill and dale, resting as often and as lomr as may be necessary, not to tire, but sufficient to create an appetite and aid digestion — using, once a week, any gentle cathartic to move the bowels once or twice only at each time, with the " I'otiie Wi?ie Tincture" given in another part of this work, or the iron and ginger^ given bolow, as deemed best or most convenient to obtain.
In cases of inf/xmmation of these organs, known by a glairy flow, cooling and astringent injections are called for, both as an act of cleanliness, as also of cure. In cases where the womb has fallen — settled low in the pelvis — tlie necessity is shown for a pessary support, until the general treatment relieves the difficulty. Costiveness, points out laxatives, whilst nature's efforts, shown by pains in the head, back, &c., call for the whole general remedies above pointed out ; and which shall be a little more particularized in the following:
Treatment. — For the weakness and general debility of the patient, let the "Tonic Wine Tincture"^' be freely taken in connection with iron to strengthen and invigorate the system ; beth-root, (often called birth-root, Indian balm, ground Illy, &c.,) the root, is the part used, Solomon's seal and columbo, spikenard, comfrey, gentian, the roots, with camomile flowers, of each 1 oz. ; with a little white-oak bark, may be added to the wine tincture to adapt it to these particular cases, taking a wine-glass, if it can be borne, from 3 to 5 times daily. Domestic wine can be used in place of the Port, in making the tonic wine tincture.
1. A very good way to take iron, is to go to a blacksmith and have him take a piece of nail-rod, a foot or two in length, and heat it, letting it cool in the cinders of the forge, which softens it; then have him file it all up for you, saving the filings on a piece of paper, with which filings, mix as much ground ginger, rubbing them thoroughly together. Dose — Half of a tea-spoon three times daily, in a little honey or mo • lasses. The natural action of the iron upon the system will be to make the stools dark, or nearly black, so do not be fearful about that condition ; for, without it, we should not be sure of the desired action of the iron. Let the use of the iron be kept up for two or three months at least, or until health is obtained.
In places where it may be difficult to get the iron filings, given in No. 1., the sweet liquor of the protoxide of iron, kept by druggists, the technical name ofwhichisZi*/. Ferri Protoxidi Dulc, may be used in place of that, a dose of which will
DK. CHASSIS hecitks.
oe about one teaspoon 3 times daily, just after meala. I have prescribed this preparation with very great success, continuing its use, in one very bad case, nearly a year.
With the above treatment, let there be a warm bath taken, once a week, putting into the water a quart or two of weaklye, made by putting a fire-shovel or two of wood ashes into the water and stirring up well, and let stand a while, then pour off into the bathing water. Castile-soap w^ill do about as well, but common soap is not as good. Wash well, and wipe off the water from the body, then with a dry coarse towel, have some one to rub the whole body and limbs briskly unti the surface glows with warmth and comfort.
For diet, moderate quantities of broiled pork, broiled beef, baked beef or mutton, wild game «&c., baked or broiled, with bread baked, at least, the day before, roast or baked potatoes, with but little butter, unless very nice, or just made, then, not very freely. This treatment, and diet, will soon overcome the softness of the flesh, and give strength for the necessary exercise, which will remove the dullness and drowsy, languid feelings. The exercise may be labor about the house, but better to be out of doors, as gardening, romping, swinging, singing and riding, or running, when it can be borne, witli agreeable company, travel, &c. The following pill will be found a gentle and excellent cathartic, or laxative :
2. Female Laxative Pill. — Aloes, macrotin, and cream of tartar, of each 2 drs. ; podophylin and ground ginger, 1 dr, each ; make into common sized pills by using oil of peppermint 15 to 20 drops and thick solution of gum Arabic mucilage. Dose— One pill at bed time, or two if found necessary, and sufficiently often to keep the bowels just in a solvent condition, but not less often than once a week.
3. Female Laxative and Anodyne Fill. — Macrotin and rhubarb, of each 10 grs. ; extract of hyoscyamus, 10 grs ; Castile-soap, 40 grs. ; scrape the soap and mix well together, forming into common sized pills with gum solution as in the above recipe. Dose — One pill, as the other, or suflicicntly often to keep the bowels solvent, but not too loose. The hyoscyamus tends to quiet the nerves without constipating the bowels.
Some females are always troubled with pains, to a greater or less degree, in the commencement of these periods, and some through the whole period. The following pill will be found very soothing and quieting to the nervous system of all such persons.
MKBICAL BBPARTMEKT. 213
4. Pill for Painful IVJenstruatiox — Anodysk — Extract of stramonium and sulphate of quinine, of each 16 grs. ; macrotia * 8 grs. ; morphine, 1 gr, ; make into 8 pills. Dose — One pill, repeating once or twice only. 40 minutes to an hour apart, if the pain does not subside. If tlie pain subsides, there is no need of repeating the dose. The advantage of this pill is that costiveness is not increased, and pain miist subside under its use.
5. Tea — Injection for Leucorrhea. — In cases of leucorrbea which continue any length of time, the following decoction, will be found very valuable as an injection :
The inner bark of the common hemlock tree, and the leaves and bark of the witch-hazel, sometimes called spotted-alder, an ounce of each, will make a quart of the decoction, a little of which, with a female syringe, should be injected, morning and evening, wliile in a recumbent position.
and pulverized alum, of each 5 grs. ; soft water, 1 pt. Simmer all over a slow fire for ten or fifteen minutes, when cool strain' and bottle, keeping well corked. When desired to use, pour out about half as much as needed and put an equal amount of soft water with it, and inject, as of the above. It may be reduced with more soft water if there should be sufficient inflammation to cause much uneasiness. A little uneasines is expected, however, and necessary.
7. . In cases of permanent falling of the womb, a good pessary may be made of a piece of tine, firm sponge, cut to a proper size to admit, when damp, of being placed in the vngirut, to hold the womb to its place. Tlic sponge should have a stout piece of small cord sewed two or three times through its center, and left of sufficient length to aid in its removal, morning and evening, for the purpose of cleansing it, using the necessary injections, &c. After having injected either No. 5 or 6 of the above, as thought preferable, the sponge having been thoroughly washed and pressed drj% it will be again introduced sufficiently high to hold the womb in place. Remembering, however, in almost all of these cases of falling of the womb, that the patient will find it necessary to keep the bed until well, or very much relieved.
ter largely into any medicine intended for its relief; and in vnost cases the iron-filings and ginger, or the sweet liquor, will be found, continued for two or three months, all the medicine required ; and the iron must not be omitted in any case whatever. Iron is the main-spoke in these female-wheels, and very valuable in general debility of males as v;ell as females.
For real hemorrhage, which may be known by the coagulation (clotting) of the blood, as the menstrual flow does not coagulate, see "Uterine Hemorrhage," or the "Styptic Balsam," but for profuse or long continued flowing or wasting, use the following :
8. Powder for Excessive Fr.ooDiNG. — Gums kiuo and catechu, of each 1 dr. ; sugar of lead and alum, of each 1-2 dr. ; pulverize all and thoroughly mix, theii divide into 7 to 10 grain powders. Dose — One every 2 to 3 hours until checked, then less often, merely to control the flow.
If any female, into whose hands this book shall come, will carefully study and use the foregoing rational remarks and prescriptions, and is not an hundred times better pleased with the results than she would have been by calling half of the physicians of the day, I should be very much disappointed, and I would be sure that the remedies did not have their common effiects, which, I feel, will not be tlie case from the great good they have already done, many times ; besides they save the delicacy of exposures, in many instances ; and they will always save the delicacy of conversing with and explaining their various feelings and conditions, to one of the opposite sex. So highly important is this fact — that the information should become general — every girl, old or young, ought to be furnished with " Dr. Chase's Recipes," and also receive all tlie additional instruction that a mother's experience can give her.
CX)LORS — Best Color for Boot, Shoe, akd Harness Edge, and Ink Which Cannot Freeze. — Alcohol 1 pt.; tincture of iron 1^ oz.; extract of logwood 1 oz.; nutgalla, pulverbeed, 1 oz.; soft water i pt.; mix. Or:
I have found shoemakers using these colors, each thinking he had the best color in the world. The sweet oil is believed to prevent the hot iron from sticking, and to make a better polish.
The first one makes a very passable ink for vrinter use, by carrying a quick hand to prevent it from spreading in the paper, from the presence of the alcohol, which, of course, is what prevents it from freezing, and that is the only argu*nent in favor of it as an ink for writing purposes.
8, Cheap Color for the Edge. — Soft water 1 gal.; extract of logwod 1 oz.; and boil them until the extract is dissolved, then remove from the fire and add copperas 2 ozs.; bi-chromate of potash and gum arable, of each i oz.; all to be pulverized.
This makes a cheap and good color for shoe or harness edge, but for cobbling or for new work, upon which you do not wish to use the " hot kit," but finish with heel-ball, you will find that if, as you pour this out into the bottle to use, you put a table-spoon of lamp-black to each pint of ii it will make a blacker and nicer finish. It makes a good color for cheap work, but for fine work, nothing will supercede the first colors given. This also makes a very good ink for writing purposes, if kept corked to avoid evaporation, which makes it gummy or sticky. See also "Grain Side Blacking."
4. Sizing for Boots and Shoes, in Treeing-out. — Take water 1 qt., and dissolve in it, by heat, isinglass 1 oz., adding more water to make up for evaporation ; when dissolved, add Btarch 6 oz.; extract of logwood, bees-wax, and tallow, of each 3 oz.; and continue the heat until all is melted and well mixed. Kub the starch up first, by pouring on sufficient boiling water for tLat purpose.
It makes boots and shoes soft and pliable, applying i\ when trceing-out, and is especially nice to clean up work which has stood long on the shelves.
5. Water-Proop Oil-Paste Blackinq. — Take camphene 1 pt., and put into it all the India-rubber it will dissolve ; when dissolved, add currier's oil 1 pt.; tallow 6 lbs.; lamp-black 2 ozs. mix thoroughly by heat.
This is a nice thing for old harness or carriage tops, aa well as for boots and shoes. Or you can dissolve the rubber in tne oil by setting them in rather a hot place for a day or two ; and save the expense of camphene, as that is of no use only as a solvent to the rubber. There are those, however, who do not like to use the rubber, thinking it rots the leather ; then use the following :
7. Neat's-Foot Oil, brought to a proper consistenc with a little bees- wax and tallow ; colored with lamp-black, will be found proof against snow or water.
8. Some, however, may prefer the following manner of preserving their boots and shoes, from a orrespondent of the Mechanics' Gazette ; but if they do ine boots must be made large, from the fact that the preparation has a tendency to shrink the leather. He says : "I have had only three pair of boots for the last six years, (no shoes) and I think I shall not require any "aiore the next six years to come. The reason is, that I treat them in the following manner :
" I p-it 1 lb. of tallow and i pound of rosin in a pot on the fire ; when melted and mixed, 1 warm the boots and apply the hot Btuft with a painter's brush until neither the sole nor the upj)er will soak in any more. If it is desired that the boots should mimediately take a polish, dissolve 1 oz. of wax in spirits of turpentine, to which add a tea-spoon of lamp-black A day after the boots have been treated with the tallow and rosin, rub over them this wax in turpentine, but not before the fire.
" Thus the exterior will have a coat of wax alone, and will ehine like a mirror. Tallow ot any other grease becomes rancid, and rots the stitching as well as the leather, but the rosin gives it that antiseptic quality which preserves the whole. Boots and shoes should be made so lar^c as to ad*
9. Black V.\uiasn for Edge.— Take 98 per cent alcohol 1 pt. ; shellac 3 ozs. ; rosin 2 ozs. ; pine turpentine 1 oz. ; lampblack i oz. ; mix, and when the gums are all cut, it is ready to use ; but bear in mind that low proof alcohol will not cut guma properly, for any varnish.
Tliis, applied to a boot or shoe edge, with a brush, gives it the shining gloss resembling much of the Eastern work. It is also applicable to wood or cloth requiring a gloss, after having been painted.
10. Varnish for Harness, TirE Best in Use. — Take 98 per cent alcohol 1 gal. ; white pine turpentine l^ lbs.; gum shellar li lbs. ; Venice turpentine 1 gill. Let these stand in a jug ii the sun or hj a stove until the gums are dissolved, then add sweet oil 1 gill, and lamp-black 2 ozs., rub the lamp-black first with a little of the varnish.
This varnish is better than the old style, from the fact that it's polish is as good, and it docs not crack when the harness is twisted or knocked about.
If you wish a varnish for fair leather, make it as the above, in a clean jug, but use no lamp-black. The pine turpentine and sweet oil make it pliable, yet not sticky.
TA.NNING, BLACKING, AND FINISHING.— Process fob Calf, Kip, and Harness, in from Six to Thirty Days. — For a 12 lb. calf skin, take terra-japonica 3 lbs. ; common salt 3 lbs.; alum 1 lb. ; put these into a copper kettle with sufficient water lo dissolve the whole by boiling.
The skin, or skins, will first be limed, haired, and treated *n every way as for the old process ; then it will be put "nto a vessel with sufficient water to cover it, at which time you will put in one pint of the composition, stirring it well ; tdding the same amount each night and morning for three >iays, when you will add the whole , handling two or three ames daily all the time tanning ; you can continue to use the tanning liquid by adding half the quantity each time, of new liquor, and by keeping these proportions for any Amount, and if you desire to give the leather the appearance of bark color, you will put in one pound of Sicily sumac.
calf skins will only require from six to ten days at mostThe japonica is put up in large cakes of about one hundred and fifty pounds, and sells, in common times, at about foux cents per pound, in New York
Byron Rose, a tanner, o'f Madison, 0., says that ono quart of oil of vitriol to fifty sides of leather^ with the japonica and alum, as above, leaving out the salt, will very much improve it ; the acid opens the pores, quickening the process without injury to the leather.
liquors in using the japonica :
The FIRST liquor is made by dissolving, for 20 sides of upper, 15 lbs. of terra japonica in sufficient water to cover the upper, being tanned. The second liquor contains the same amoimt of laponica, and 8 lbs. of saltpetre also. The third contains 20 lbs. of japonica, and 4^^ lbs. of alum. The fotirth liquor contains only 15 lbs. of japonica, an^l H Jhs. of sulphuric acid; and the leather remains 4 days in each liquor for upper ; and for sole, the quantities and time ai-e both doubled. They count 50 calf skins in place of 20 sides of upper, but let them lie in each liquor only 3 days.
3. Deer Skins — Tanning and Bitffing for Glovfs. — For each, skin, take a bucket of water, and put into it 1 qt. of lime ; let the skin or skins lay in from 3 to 4 days ; then rinse in clean water, hair, and grain ; then soak them in cold water to get out the glue ; now scour or pound in good soap suds, for half an hour; after which take white vitnol, alum, and salt, 1 tablespoon of each to a skin ; these will be dissolved in sufficient water to cover the skin and remain in it for 24 hours ; wring out as dry as convenient ; and spread on with a brush i pt. of currier's oil, and hang in the sun about 2 days ; after which you will Bcour out the oil with soap suds, and hang out again until perfectly dry ; then pull and work them until they are soft ; and if a reasonable time does not make them soft, scour out in suds again as before, until complete. The oil may be saved by pouring or taking it from the top of the suds, if left standing a short time. The buff color is given by spreading yellow ochre evenlv over the surface of the skin, when finished, rubbing it in weU with a brush.
The foregoing plan was pursued for a number of years by a brother of mine, and I have worn the gloves and know the value of the recipe ; but there are plans of using acid, and if the quantity is not too great, there is no reason in the Yorld why it may not be used ; the only caution necessary is
stroying the fiber.
4. TAOTaxa with Acid. — After having removed the hair, scouring, soaking, and pounding in the suds, &c., as m the last recipe, in place "of the white vitriol, alum, and salt, as there mentioned, take oil of vitriol, (sulphuric acid) and water, equal parts of each, and thorouglily wet the flesh-side of the skin with it, by means of a sponge or cloth upon a stick ; then foldi g up the skin, letting it lie for 20 minutes only, having tadyn a solution of sal soda and water, say one lb. to a bucke of wnter, and soak the skin or skins in that for 2 hours, whet
frou ■^^^ll Avash in clean water and apply a little dry salt,lettinn le in the salt over night, or tliat length of time ; then removg the flesh with a blunt knife, or, if doing business on a large scale, by means of the regular beam and flesh-knife ; when drye or nearly so, soften by pulhng and rubbing with the hands, and also with a piece of pumice-stone. This, of course, is the quickest way of tanning, and by only wetting the skins with, the acid and soaking out in twenty minutes, they are noe rotted
5. Another Method. — Oil of vitriol i oz.; salt 1 teacupof milk sufficient to handsomely cover the skin, not exceeding 3 qts.; warm the milk, then add the salt and vitriol; stir the skin in the Kquid 40 minutes, keeping it warm ; then dry andwork it as directed in No. 4.
6 Tanntng Sheep-Skins, Applicable fob Mittens Door-Mats, Rodes, &c. — For mats, take two long-wooled skins, make a strong suds, using hot water ; when it is cold wash the skins in it, carefully squeezing them between the hands to get the dirt out of the wool ; then wash the soap . out with clean cold water. Now dissolve" alum and salt, of each half a pound, with a little hot water, which put into a tub of cold water sufficient to cover the skins, and let them soak in it over night, or twelve hours, then hang over a pole to drain. When they are well drained, spread or stretch carefully on a board to dry. They need not be tacked if you will draw them out, several times with the hand, while drying. When yet a little damp, have one ounce, each, of saltpetre and alum, pulverized, and sprinkle on the fleshside of each skin, rubbing in well ,• then lay the flesh-sides together and hang in the shade for two or three days, turn ingthe under skin uppermost every day, until perfectly dry Then scrape the flesh-side with a blunt knife, to remove any remaining scraps of flesh, tiim off projecting points, and rub
the fleoli-side with pumice or rotten stone, and with tin hands ; they will be very white and beautiful, suitable lot a foot^mat, also nice in a sleigh or wagon of a cold day. They also make good robes, in place of the bufi'alo, if colored, and sewed together. And lamb-skins, (or sheep-skins, if the wool is trimmed off evenly to about one-half or three fourths of an inch in length) make most beautiful and warm mittens for ladies, or gentlemen.
7. Tanning Fur and Other Skins — Fifty Dollar Kecipe. — First, — Remove the legs and other useless parts, and soak the skin soft ; then remove the fleshy substances and soak in warm water for an hour j now :
Take for each skin, borax, saltpetre, and glauber-salts, of each i oz., and dissolve or wet with soft water si&cient to allow it to be spread on the flesh-side of the skin.
Put it on with a brush, thickest in the centre or thickest part of the skin, and double the skin together, flesh-side in, keeping it in a cool place for twenty-four hours, not allow iug it to freeze, however.
Second, — Wash the skin clean, and then : Take sal-soda 1 oz. ; borax i oz. ; refined soap 2 ozs. ; (Col gate's white soap is recommended as the best, but our " Whit* Hard Soap" is the same quality, ) ; melt them slowly together, being careful not to allow them to boil, and apply the mixture to the flesh-side as at first — roll up again and keep in a wwm place for 24 hours.
saturate the skin, then :
Take alum 4 ozs. ; salt 8 ozs. ; and dissolve also in hot rain water ; when sufficiently cool to allow the handling of it without scalding, put in the skin for 12. hours ; then wring out Uxe water and hang up, for 12 hours more, to dry. Repeat this last soaking and drying from 2 to 4 times, according to the desired :oftne8s of the skin when finished.
Now dip the skin in warm rain water having sufficient Baleratus in it to make it rather strong, or as in the third head of last recipe, and work and squeeze it well for a few minutes, then wring dry as convenient and put it into the vitriol mixture for fifty minutes, stirring all the time; now wring out and soak awhile ; and finally dry and work until Boft.
9. Grain-side Blacking, for Ten Cents a Barrel. — Take a barrel and put into it quite a quantity of old iron, cast or wrought, then fill nearly full of soft wMer, and add 1 pt. of oil of vitrol ; stir it up well, and in a month or two you have just as good blacking for the grain-side, as could be made by using vinegar in place of water.
in the leather.
Tanners will, of course, first apply the urine before applying the blacking, saving from ten to twenty dollars yearly, in this way, instead of the old plan of using vinegar.
10. French Finish, for Leather. — Take a common wooden pail of scraps, (the legs and pates of calf-skins are the best) and put a handful each, of salt and pulverized alum amongst them and let them stand three days ; then boil them until you get a thick paste; in using you will warm it ; in the first application, put a little tallow with it, and for the second, a little soft soap, and use it in the regular way of finishing, and your leather will be soft and pliable, like the French calf-skin.
ness, not otherwise obtained.
11. French Patent Leather. — The process which ha« been so successfully adopted by the French artisans in glazing leather, bo as to give it the repute for superior quality
and beauty which it now universally sustains, is as follows :
Work into the skin with appropriate tools three or four sue cessive coatings of drj^ing varnish, made by boiling linseed-oii with white-lead and litharge, in the proportion of one pound of each of the latter to a gallon of the former, and addiiig a portion of chalk or ochre — each coating being thoroughly dried before thp. application of the next. Ivorjr black is then substituted for the chalk or ochre, the varnish thmned with spirits of turpentine, and five additional applications made in the same manner as before, except that it is put on thin and not worked in. The leather is rubbed down with pumice-stone, in powder, and then placed in a room at 90 degs., out of the way of dust. The last varnish is prepared by boiluig i lb. of asphaltum with 10 lbs. of the drying oil used in the first step of the process, and then stirring in 5 lbs. of copal varnish and 10 lbs. of turpentine.
DRYING OILS — To Prepare for Carriage, Wagon, ajto Floor Patnttng. — Take linseed oil 1 gal., and add gum shellac 8- lbs. ; litharge i lb. ; red-lead i lb. ; umber 1 oz. Boil slowly, 2 or 3 hours, until the gums are dissolved.
Grind your paints in this (any color) and reduce with turpentine. Yellow ochre is used for floor painting. This dries quick and wears exceedingly well.
2. Drying Oil, Equal to the Patent Dryers. — Linseed-oil 2 gals., and add litharge, red-lead, and umber, of each 4 ozs., and sugar of lead and sulpliate of zinc, of each 2 ozs.
fal., and put into it gum shellac | lb. ; litharge and burned Turey umber, of each % lb. ; red-lead i lb., and sugar of lead 6 ozs. Boil in the oil until all are dissolved, which will require about 4 hours ; remove fiom the fire, and add spirits of turpentine 1 gal.t and it is done.
that place, I obtained the foregoing recipe. It was published in a work printed in Columbus, 0., devoted to tha art of painting, From this fact, and also that the gentlemen from whom I obtained it, had tested it and were using it, T have not myself tried it, but know, from the nature of the articles used, that nothing better will be required.
4. Another. — Another drj-er is made by taking linseed oil 5 gals., and adding red-lead and litharge, of each 3^ lbs. ; raw umber 1^- lbs. ; sagar of lead and sulphate of zinc, of each i lb. ; pulverize all the articles together, and boil in the oil until dissolved ; when a little cool, add turpentine, 5 gals., or to make it of a proper consistence.
The gentleman of whom I obtained this recipe paid ten dollars for it. He was using it successfully, and said he used two or three drops of it to a quart of varnish also, and especially when the varnish did not dry readily.
OIL — PAINT — To Reduce with Water. — Take gum shel lac 1 lb. ; sal-soda \ lb. ; water 3 pts. ; put all into a suitable kettle and boil, stirring till all is dissolved. If it does not all dissolve, add a little more sal-soda ; this, when cool, can be bottled for use. K it smells bad when opened it does not hm't it,
Directions for Using. — Mix up two quarts of oil paint as usual, except no turpentine is to be used — any color desired. Now put one pint of the gum shellac mixture with the oil paint when it becomes thick, and may be reduced with water to a proper consistence to lay on with a brush. Two coats will be required, and with the second coat sand may be applied if desired. I used this upon a picket-fence with white-lead and yellow ochre for the body and a little lamp-black to give it a dark shade, putting on sand with the second coat. It is still firm and good, the work being done nearly four years ago.'
The sand was applied with a tub-like box, with many email holes to allow the even spreading of the sand, as with a pepper-box. I do not regret using this kind of paint, nor the sanding, as it adds much to the durability of any outdoor painting. But a better plan of sanding is represented in the " Painter's Sanding Apparatus " below.
? Another Method.— Take soft water 1 gal., and dissolve in It, pearlash 3 ozs.: bring to a boil, and slowly add shellac \ lb.; when cold it is ready to be added to oil-paint, in equal pro* portions. The expense of these is only one-third of oil-paint
Some persons may think it bad policy to learn painters to reduce oil-paint with water, but I think every man should be told of the plan, who is going to have a job of work done, and if he makes up his mind to try apy thing of the kind, it is then his own business j and I am perfectly sincere in recommending it, for if there was any great fault in it four years would show it.
8. It is made of tin ; the tube C, enters upon the no»n<# of a small bellows ; the sand is put into the funnel B, which stands perpendicular upon the apparatus when the broad mouth-piece A, is held level in using. The funnel discharges the sand, just before the nozzle of the bellows ; and by working the bellows the sand is blown evenly 'upon the freshly put on paint, through the mouth-piece A, the escape orifice not being over the sixteenth part of an inch in depth, and may be made two and a half or three inches wide.
Many persons like the plan of sanding generally, after painting ; but from the fact that when it is desired to renew the paint, brushes cannot last long upon the sand, I think it enly proper to sand fences or fronts, where boys* knivet would be too freely used.
The skins that dry upon the top of paint, which has been left standing for any length of time, may be made fit for use again by covering them with the sal- soda-water and soaking them therein for a couple of days ; then heat them, adding oil to reduce the mixture to a proper consistence for paintmg, and straining. Painters who are doing extensive business will save many dollars yearly by this rdmple process.
Dissolve sufficient sal-soda in a bucket of water to malcc it quite strong ; wash the roof thoroughly with the aoda-watcr and let it remain until it is washed off by the rains, or after a few kours, washing off with clean water, rinsing well.
When dry give it one coat of pure Venetiaa-red, mixed with one-third boiled, and two-thirds raw linseed-oil ; tho second coat may be any color desired. The soda-water dissolves the rosin remaining after scraping ; destroys the greasy nature of the solder, and of the new tin, so that there will be sufficient '■'Grip" for the paint to adhere firmly. The pure Venetian-red is one of the most durable paints for metallic-roofs, but is often rejected on account of its color. The above mode of painting will set aside ihis difficulty.
2. Fiue-Pkoof Paint — for Roofs, «&c. — Slack stone-lime by putting it into a tub, to be covered, to keep in the steam. When slacked, pass the powder through a fine sieve ; and to each 6 qts. of it add, 1 qt. of rock-salt, and water 1 gal.; then boil and skim '".lean. To each 5 gals, of this add, pulverized alum 1 lb. pulveHzed copperas i lb.; and still slowly add powdered potasl i lb.; then fine sand or liickorj- ashes 4 lbs.
N /W add any desired color, and apply with a brush — looks better than paint, and is as durable as slute. It stops smal. leaks in roofs, prevents moss, and makes it incombustible • and renders brick impervious to wet. — Maine Farinei\
3. "Water-Proof, Oil- Rubber Patxt. — Dissolve about 6 lbs. of India rubber in 1 gal. of boiled linseed- oil, by boiling. If this is too thick, reduce with boiled-oil ; if too thin, use more rubber. ^
material.
Frostinq Glass. — The frosty appearane 3 of glass, which we oilca -oo, where it is desired to keep out tho sun, oi " Man !i observing eye," is done by using a paint composed as follows :
of it, a stick sharpened to the width of line you wish to appear in the diamonds, figures, or squares, into which you choose to lay it off"; most frequently, however, straight lines are made an inch or more from the sash, according to the size of light, then the centre of the light made into diamonds.
ORIENTAL — CaYSTAJi Painting. — The colors used are Prussian-blue, crimson, white, and yellow-lakes, Rossean, white-zinc, and No. 40 carmine. Druggists keep them, in small tubes. They must be mixed with Demar-vamish, rubbing with a table-kuife or spatula upon glass.
Directions for Making Various Shades, or Compound Colors. — Proportiou them about as follows — for green 1-5 blue, 4-5 yellow— purple, 1-6 blue, 5-6 <;rim8on — orange, i crimson, f yellow — wine-color, 113 blue, 1112 crimson — pink, add a liule crimson to white-zinc — brown, mix a dark purple and add yellow according to the shade desired — black, add crimson to dark green until llie shade siiits you — to njake the compound colors Bghter, add the lightest color in it, and make darker by using more of the darkest color in the compound. For backgroimd* —white, white-zinc, or pink wliite with turpentine and boiled iuseed oil and Demar-varnish — black, lamp-black, with asphal um-vamish and boiled linseed-oil and turpentine in equal quantities— Qesh-color, white-zinc with a small portion of crimson and chrome-yellow to suit. For sketching out the figures on the ground-work, use a little lamp-black with asphal tum-varnish, turpentine and boiled linseed-oil lo make it flow freely.
Directions for Painting.^ — Make your glass perfectly clean, and place it over the picture you wish to copy ; then with the sketching preparation, trace on the glass all tht \it.cB connected with the figures of the picture which yoa are cppying, being' careful to sketch vines very distinct; when the sketching is done and dry, proceed to lay on the background inside of the sketched lines until all the sketching is closed ; and when the background is dry, proceed to put on the colors, commencing with green, if any in th« figures, ending with yellow. When the colors are all kid, put the background upon the balance of the glass ; and when all is dry have tin foil crumpled very much in yotu hand, and then partly straightened out, and lay it ever the figure and keep it in its place by pasting paper over it in Buch a manner that it cannot slip away, letting the pa»ei cover the whole back of the glass, or a wood-back eat/ *»«
placed behind the glass, and all is complete, and will look well or ill; according to the practice nnd taste of the painter. 2. Fancy Green. — Unscorched, pulverized coffee, put into the white of an egg will, in twenty-four hours, produce a very beautiful green for fancy paiuting—proof of poi-son, in unbrofrned coffee.
Have a fi-ame of a little less si-'e than the paper to be prepared, and apply paste or thick gum solution to one side and the outer edge of it ; wet the popcr in clean water and lay it upon the frame and press it down upon the pasted side of the frame, and turn the outer part of the paper over the outside of the frame upon the paste there, which holds it firm ; and when it becomes dry it is tight like a drumhead; whilst in this condition,- with a brush saturate it with the above mixture; three or four coat« will be needed, giving each one time to dry before applyinj^ the next. Only sufficient is needed to make it transparfint, so that when you wiflh to sketch a rose, or other flower or leaf, from nature, the paper can be placed upon it like the glass in the " Orifttital Painting" ; then trace the lines ard finish it up in the same way also, as there described ; or that you may see through it in taking perspective views of distant scenery.
DOOR PLATES— To Make.— Cut your f lass the right size, and make it perfectly clean wit'i alcohol or soap; then cut a strip of tin-foU sufficiently long and wide for the name, and with a piece of ivory or other burnisher rub it lengthwise to make it smooth; now wet the glass witli the tongue, (as saliva is the best Sticking substance,) or If the glass is very large, use a weak solution of gimi arable, or the white of an egg m half a pint of water and lay on the foil, rubbing it down to the glass -nilh a bit of cloth, then also with the burnisher ; the more it is burnished the better will it look ; now mark the width on the foil which is to be the hightof the letter, and put on a straigbt-edge and hold it firmly to the foil, and with a shai'p knife cut the toil and take off the superfluous edges ; then either lay out the letters on the back of tlje foil, (so they shall read correctly on the front) by your own judgment or by means of pattern-letters, which can be
Eurchascd for that purpose ; cut with the knife, carefully holdig down the pattern or straight-edge, whichever you use ; then rub down the edge of all the letters v.'ith the back of the knife, or edge of the burnisher, which prevents the black paint or lapaa which you next put over tlie back of Uie plate, liom get-
ting unde. the foil ; having put a line above and one lyoi'-rtr the name, or a border around the whole plate or not, as you oargain for the job. The japan is made by dissolving asphaltum in just anough turpentine to cut it (see " Asphaltum Varnish ") ; apply with a brush as other paint over the back of the letters and over tlie glass, forming a background. This is used on the iron frame of the plate also, putting it on when the plate is a little hot. and as soon as it cools it is diy. A little lamp-black may be rubbed into it if you desire it any blacker than it is without it.
If you choose, you can remove every other foil letter, after the japan is dry, and paint in its place, red, blue, or other coloi'ed letters, to make a greater variety out of which for your customers to choose, as the one they desire you to follow in getting up their plate. Tin foil liein;,,' thicker than silver or gold foil, will not show the paint through il in little spots as they do ; but if these foils are desired to be used, you can put on two thicknesses by proceeding iia follows, which prevents the paint from showing through them : Lay en the first coat of the.'^e foils the same as directed for the tin-foil, and smooth it down by rubbing oa the front of the glass; then breathe on it until a dampne« is caused ; now put on the second and burnish well, havij:g paper over it ; but instead of the knife to cut around your pattern or straight-edge, take a sharp needle, using the point, make lines through the leaf around the pattern letter or straight-edge ; then with a bit of Jewelers' wood, or other hard wood, made to a narrow and pharp point, remove all up to the lines, both in and around the letters, as these foils have not the substance to peel off as the tin-foil , japanning over them the same as the other letters. Paper letters can be cut out of advertisements and put on by wetting the glass the same as for the foil, jappanning over them, and when dry, removing them and painting the places out of which they came with various colors as desired, as the japao will not peel, but makes a sharp and distinct edge ; and these painted letters look well, in this way; and by taking %dvantage of printed letters, saves the skill and time necett. sary to ibrm them.
To illustrate ; in the name given below, A may be gold foil; W will be blue; C, red; H, black; A, gold-foil; S, blue ; E, red ; M, black ; and again D, gold-foil, which any one can see makes a more showy plate than if all were of one foil, or one color.
Set your glass in the frame with putty and put a thin coat of putty over the whole plate, as the plaster of Paris filling which is generally used soon eats out the japan or paint, and spoils the job. Persons with any ingenuity can very soon make a nice plate if they will pay attention to the above rules, as well as to pay five dollars for instructions, ar^ a little practice must be had to become perfect, even if you do pay five dollars for an hour or two's telling and showing. Shellac varnish colored with lamp-black is good in place of the japan. See " Varnish — Transparent, for AV'ood.''
ETCHING AND GRINDING UPON GLASS-Fon Signs, OK Side Lights.— Take the " Asphaltum Vamisli," and with a small pencil lay out the name or design, not putting the varnish upon the letters, but around it, leaving the space which the letters of the sign are to occupy, free and clear, as seen in the following door plate, represented in the wood cut, and by the way, a very nice style of letter for that purpose also, we think:
ITie varuish is to cover the black surface in the sign or name. TMe white line around the outside represents a border which improves the appearance of the plate; when the varnish is dry iiiive some melted bees-wax and as it begins to cool, with a knife take some of it up and scrape it olf upon the edge of the glass, being etched, so as to form a wall to hold tlie acid upon the glass while etching ; now lay the glass flat and pom- a little fiouric acid on to the name, letter, or design thus prepared, and let it remain on for one hour, not allowing the glass to be touched or ui'jved for tliat time ; then pour off the acid into your bottle, and it can be used again. The asphalt prevents the acid from eraing or etching only the letter, and the wax wall prevents th« acid from flowing otf and being wasted. When you pour ott the acid wash the glass with a little water, scrape off the wax^ and remove the asphalt with a little turpentine, and all is done.
The above directions are for plain glass ; but if you desire, you can gild the letter which is etched (eat out,) or you can gild all except the letter, if desired, as described in the recipe for " Door i'lates," or you can grind the surface of the gla«8
B8 described under the head of " Glass-grinding for SigB«| Shades," &c. This applies equally well to " flashed," or what is called "stained glass," worked in the same way as above, putting the design or letters upon the stained side, which eats away the color and leaves the design clean and white ; or you can etch only a part of the way through thr Btain, which shows up the letter or flower lighter in coloi than the rest of the glass, which makes it look very beautiful for side-lights in halls, lamps, druggists' windows, &c.
There are two kinds of colored glass — one is called " Pot metal," the other " Flashed." The pot-metal glass is made by mixing the stain or coloring with the melted glass, while ■flaking, and consequently is alike all the way through. — The stained glass is made by applying tlie color to one side of the glass after it is made, then applying sufficient heat to allow it to take hold of the glass only — the color is all on one side ; this is the kind desired.
If it is desired to etch upon druggists' or other jars, it can be done by preparing the name to be put on, with the varnish and wax ; then have a lead box without top or bottom ; in shape on the lower edge to fit the shape of the jar, and press this down upon the wax to make it tight; then pour your acid into the box which keeps it in its place the same as the wax does on a flat surface. Ornaments or flourishes can be put on as well as letters.
The old plan was to cover the whole surface with wax, then remove it from the letter, which was very slow and troublesome, and if a bit of wax remained upon the bottle, the acid could not cut where the wax remained, then to hold the glass over the fumes of the acid, instead of putting the acid upon the glass.
2. Glass-Grinding for Sings, Shades, &c. — After you have etched a name or other design upon uncolored ^lass, and wish to have it show off to a better advantage by permitting the light to pass only through the letters, you can do so by :
Tah'ng a jiiece of flat brass sufficiently large not to dip wjto Uie letters, but pass over them when gliding upon the surlact" of tlie glass ; then with flour of emery, and keeping it wet, you can %rmd the wl.ole siu-lace, very quickly, to look like the groimd glHSS globes, often seen upon lamps, except the letter whiri ui eaten below the general Hurface.
grinding, if preferred.
3. FLUORie Acid, To Make for Etching Purposes. — You can make yoiiv own fluoric (sometimes called hydro-fluoric) acid, by getting tlic fluor or Derbysliire spar, pulverizing it and putting all of it into aulpkuric acid wliicli the acid will cut or disfcolve.
Druggists through the country do not keep this acid generally, but they can ^et it in the principal cities and furnish it for about seventy-five cents per ounce, and that ounce will do at least fifty dollars worth of work. It is put up in gutta pereha-bottles, or lead-bottles, and must be kept in them when not in use, having corks of the same material. Glass, of course, will not hold it, as it dissolves the glass, otherwise it would not etch upou it.
PORCELAIN FINISH— \ery Hard and White, for Parlors.— To prepare the wood for the finish, if it be pine, give one or two coats of the " Varuish—Tiansparent for Wood," which prevents the pitch from oozing out causing the finish to turn yellow ; next, give the room, at least, four ooats of pure zinc, which may be ground in only sufficient oil to enable it to grind properly, then mix to a proper consistence with turpentine or naptha. Give each coat time to dry. When it is dry and hard, sandpaper it to a perfectly smooth surface when it is ready to receive the finish, which consists of two coats of French zinc ground in, and thinned with Demar-vwrnish, until it works properly tmder the brush.
Mr. Miles, of this city, one of our (Scientific painters, has been sufficiently kind to furnish me this recipe prepared expressly for this work, therefore, the most implicit confidence may be placed in it, yet any one can judge for themselves, from the nature of the articles used, that it must be white and hard. He goes on to say that if the French-zinc in (Tarnish cannot be procured, the varnish may be whitened with zinc ground in oil as a very good substitute, being careful not to use too much, in which case it will diminish th>a gloss, and be more liable to turn yellow. A little turpentine or naptha may be added, if too thick to work well, but in no instance should oil be used to thin the paiut.
This finish, if properly applied, is very beautiful, and although purely white, may be kept clean more easily than other kinds of painting by simply using a dusting brush j or
the better way.
N. B. — Not a particle of wliite-lcad should be used where this finish is to be applied, either in the priming, or any subsequent coats, or a brush used that has been in leaa without being thoroughly cleansed, as a yellow hue will soon present '•tself, which is caused by a chemical change taking place ib;twecn the lead and zinc
' PAINTERS' ECONOMY IN MAKING COLONS. -Pri'sBiAN Blue. — 1st. Take nitric acid, any quantity, and as mucli iron shavings from the lathe as the acid will dissolvi.-; heat the iron as hot as can be handled with the hand ; then add it to Ilia acid in small quantities as long as the acid will dissolve it, then slowly add double the qnantitj' of soft water that there was of acid, and put in iron again as long as tiie acid will dissolve it 2nd. Take Prussiate of potash, dissolve il in hot water to make a strong solution, and make sufficient of it with the first to give the depth of tint desired, and the blue is made. Or:
2. ANOTnEu Method. — A very passable Prnssian-bhie is made by taking suljihale of iron (copperas) and Prussiate of potash, eqna.' parts of each, and dissolving each separately in water, then mixing the two waters.
3. Chrome Yellow. — 1st. Take sugar of lead and Pariswhite, of each 5 lbs.; dissolve them in hot water. 2nd. Take bi-chromate of potash GJ ozs., and dissolve it in hot water also, each article to be dissolved separately, then mix all together, putting in the bi-chromate last. Let stand 24 hours.
4. Chrome Green. — Take Paris-white di lbs.; sugar of lead, and blue vitriol, of each 3^ lbs.; alum lOi^ ozs.; best soft Prussian blue and chrome yellow, of each 3i lbs. IMix thoroughly while in fine powder, and add water 1 gal., stirring well and let stand 3 or 4 hours.
5. Green, Durable and Cheap. — Take spruce yellow, and color it with a solution of chrome yellow and Prusaiau-biue, until you give it the shade you wish.
G. Paris Green. — Take unslacked lime of the best quality, slack it with hot water ; then take the finest part of the powdci and add alum water, as strong as can be made, sufficient to foma a thick paste, then color it with bichromate of potash and sulphate of copper, until the color suits your fancy. N. B.— The sulphate of copper gives the color a blue tinge — the bi-cliromate ol potash a yellow. Observe this and you will never fail.
7. Another Method. — Blue vitriol 5 lbs.; p^jrar of lead 6^ lbs.; arsenic 2i lbs.; bichromate of potash U ozs.; mix them thoroughly in fine powder, and add water 3 pit., mixing well again and let stand 8 or 4 hours.
8. Pea Brown. — Ist. Take sulphate of copper, any quantity And dissolve it in hot water. 2nd. Take prussiate of potasli, dissolve it in hot water to make a strong solution ; mix of the two gjilutions, as in the blue, and the color is made.
9. Rose Pink. — Brazil wood 1 lb., and boil it for 2 houi-s, having 1 gal. of water at the end ; then strain it and boil alum 1 lb. in the shme water until dissolved ; when sufficiently cool to admit the hand, add muriate of lin f oz. Now have Pariswhite 12^ lbs., moisten up to a salvy consistence, and when tha first is cool stir them thoroughly together. Let stand 24 houra.
When any of the above mixtures have stood as mentioned, in their respective recipes, all that is necessary is to drain off the water by placing the preparations into muslin bags for that purpose, and then exposing the mixture to the air, to dry for use.
Glass, stone, or wood vessels only should be used, as tha acids soon work upon iron, tin, copper, &c., givingyou a tingo not desired in the color, and always observe that if water is to be mixed with strong acids, it must be added slowly, especially if in light vials, or you will break the vessel by means of tlie great heat which is set free by the combination Painters can u.se their own judgment about making these colors ; but if they do not do it ibr profit there will ba pleasure in testing them, eveu in vials-full only, as the chemical action is just as fine in small as in large quantities.
Bissolve saleratus 4 ozs., to water 1 qt., sufficient to cover tha flliis, and boil them in it for half an hour ; then take out, wash and dry them ; now stand them in ajar, filling it up with raiawaler and sulphuric acid, in the proportion of water 1 qt., to acid 4 ozs.
If the files are coarse, they will need to remain in about twelve hours ; but for fine files, six to eight hours will be all-sufficient. When you take them out, wash them clean, dry quickly, and put a little sweet oil upon them, to prevent rust.
workers will only require a short time to take the articles out of their files, as the soft metals with which they become filled, are soon dissolved, leaving the files about as good aa new. For blacksmiths and saw-mill men, it will require the full time.
covered when not in use.
If persons, when filing, would lift up the file, in carrying back, there would be no necessity of a re-cutting, but in draicing it back they soon turn a wire-edge, which the acid removes. It also thins the tooth. Many persons have doubted this fact ; but I know that the common three-square file, (used for sharpening saws,) when worn out and thrown by, for a year or two, may be again used with nearly tke Bame advantage as a new one. The philosophy of it is this — the action of the atmosphere acts upon the same principle of the acid, corrodes (eats off) the surface, giving a-new, a square, cutting edge. Try it, all ye doubtful ; I have tried both, -ind know their value. Boiling in the saleratuswater removes grease, and allows the acid to act upon the Bteel.
Apply a light coat of this, and you can lay away any arti cles not in constant use, for any length of time, such aA knives and forks, or mechanics' tools which are being laid by, or much exposed. But for axes or other new tools, which are exposed to the air before sold, you will find the following varnish preferable :
2. Transparent, for Tools, Plows, &c. — Best alcohol 1 gal.; gum sandarach 3 lbs.; gum mastic \ lb. Place all in a tin can which admits of being corked ; cork it tight, and shake it frequently, occasionally placing the can in hot water. WheB dissolved, it is ready to use.
varnish, and add sufficient olive oil to make it feel a little preasy ; then add nearly as much spirits of turpentine as there IS of varnish, and you will probably seek no farther.
oughly.
For ground Bteel-plows, or other ground steel, one or two eoata of this will be found sufficient to give a nice blue appearance, like highly-tempered steel ; some may wish a little more blue ; if so, add the Prussian-blue to your liking. Copal varnish is not so transparent as the Demar, but if you vrill have a cheap varnish, use No. 4.
6. Black, Having a Polish, for Iron— Pulverized gum asphaltum 2 lbs. ; gum benzoin J lb. ; spirits of turpentine 1 gal. o make quick, keep in a wann place and shake often ; shade to iuit with finely ground ivory black.
Apply with a brush. And it ought to be used on iron exposed to the weather as well as on inside work desiring a nice appearance or polish. Or :
7. Varnish for Iron. — Asphaltum 8 lbs. ; melt it in an iron kettle, slowly adding boiled linseed-oil 6 gals. ; litharge 1 lb. ; and Bulphat€ of zinc i lb. ; continuing to boil for 3 hours ; then add ilark gum amber 1| lbs., and continue to boil 2 hours longer When cool reduce to a proper consistence, to apply with a brush, with spmts of turpentine.
8. I WISH here, also, to state a fact which will benefit those wishing to secure vines or linibs of trees to the side of a white house, with nails, and do not wish to see a streak of rust diwa the white paint, as follows :
vent rust, proven by ever eight years trial.
WELDING — Cast Stkfl Without Borax.— Copperas 8 ozs. ; saltpetre 1 o?. ; common salt 6 ozs. ; black oxyde of manganese 1 oz. ; Prussiate of potash 1 nz. ; all pulverized and mixed with nice welding sand 3 lbs., &nd use it the same as you nould sand.
Higher tempered steel can be used with this better than with borax, as it welds at a lower heat — such a? pitchfork dues, toe-corks, &c. The pieces should be held together (rhile heating. I have found some blacksmiths using it
without tha Manj^aneee ; but from what I know of the purifying properties of that article upon iron, 1 am sure it must be preferable with it, as that is the principal purifyer in the next recipe.
POOR IRON, — To Improvk. — Black oxide of manganese 1 part ; copperas and common salt 4 parts each ; dissolve in soft water and boil until dry ; when cool pulverize and mix quite freely with nice welding sand.
When you have poor iron which you cannot afford to thiow away, heat it and roll it in this mixture, working for a time, re-heating, «S:e., will soon free it liom all imj)uritie8, which is the cause of its rottenness. By this process you can make good horse-nails, even out of only common iron.
WRITING UPON Iron ou Steel, Silveb or Gold, not TO Cost the Tenth Part of a Cent per Letter. — Jluriatic acid 1 oz. ; nitric acid i oz. Mix, when it is ready for use.
Directions — Cover the place you wish to mark, or write upon, with melted bees-wax ; when cold, write the name plain with a file point or an instrument made for the purpo.se, carrying it through the wax and cleaning the wax all out of the letter ; then apply the mixed acids with a feathery carefully filling each letter J let it rem?in from one to ten minutes, according to the appearance desired ; then put on some water, which dilutes the acids and stops the process. Either of the acids, alone, would cut iron or steel, but it requires the mixture to tiike hold of gold or silver. After you wash off the acids it is best to apply a little oil
MILL-PICKS, -To Temper.— To 6 qts. of soft water, put in pulverized corrosive sublimate 1 oz., and 2 hands of common salt ; when dissolved it is ready for use. The first gives toughness to the steel, whilst the latter gives the hardness. I have found those who thmk it better to add sal-ammoniac, pulverized, 2 ozs., to the above.
DiRECTiONNS. — Heat the picks to only a cherry red and plunge them in and do not draw any temper. In working mill-picks, be very careful not to over-heat th2m, but work them at as low a heat as possible. The reason why so many fail in making good picks, is that they don't work them a* as low heat as they should. With care upon that poiut, and the above fluid, no trouble will be experienced, evea OQ the best diamond burrs. Be sure to keep the pr«par*-
don covered when not in use, as it is poison. Pigs or dogi might drink of it, if left uncovered. This is the mixture which lias gained me the name of having the best prepararation in use for mill-picks, and the certificates on this subject, but as I have some others which are very highly spoken of, 1 give you a few others.
2. An English Miller, after buying my book, gave me the following recipe, for which he paid ten dollars. He had used it all his life, or from the time he began business for himself, (about thirty years,) and he would use no othof.
There must be something in this last, as the next one 1 obtained at least five hundred miles from where I did this, and both from men who knew their value, and yet they resemble each other near enough to be called " The twins."
4. MiLi.-PiCK3 AND Saw Gi'mmei^s, to Tempeu. — Saltpetre and alum, eacli 2 ozs. ; sal-ammoniac i oz. ; salt 1^ lbs. ; soft water i> gals. Ileal to a chcrry-rcd and plunge them in, and draw no temper.
The steel must never be heat above a cherry-red, and in working and drawing the picks there ought to be quite an amount of light water-hammering, even after the steel is Quite cool. Once more and I am done : yet it may be pos?jble that the last, in this case, maybe the best; read it.
BOR. Water 3 gals. ; salt 2 qts. ; sal-ammoniac and saltpetre, of each 2 >zs. ; ashes from white ash bark 1 shovel, which causes the picks to scale clean and white as silver.
I obtained this recipe of a blacksmith who paid young Mr. Church five dollars for it, he coming into the shop and showing him how to work the picks, as also the composition— his instructions were, not to hammer too cold, to avoid flaws ; not to heat too high, which opens the pores of the iteel, nor to heat more than one or two inches of tho pick when tempering The gentleman says, if care is taken io beating and wjrking, that no other tempering liquid will
equal it, yet he spoiled the first batct by over heating, ev« •ifter Mr. Church had taken all paiw to show him. Thej (the Messrs. Church) have picks sent S) them, for tempering, from Illinois and even Wisconsin
BUTCHER-KNIVES— Sprino-Temper and BeaumruL Edge. — In forging out the knif» as you get it near to its proper thickness, be veiy careful «\ot to heat it too high, and to water-hammer as for mill p'cks; when about to temper, heat only to a cherry-red and hold it in such a way that you can hold it plumb a.s you -pvi it into the water which prevents it from springing — put i' plumb into the water and it will come out straight.
Take it from tlie water to the fire and p»ss it through the blaze until a little hot ; then rub a candle over t upon both sides and back to the fire, passing it backward anc forward, in the blaze, turning it over often to keep the heat ev*n over the whole surface, until the tallow psisses off ad though \t went into the steel ; then take out and rub the candle over it again (on both sides each time) and back to the fire, passing i- as before, until it starts into a blaze, with a snap, being careml 'hat the heat i> even over the whole length and width of the toe', then rub th« tallow over it again and back, for 3 times, quickly "s it bums oflf; and lastly rub the tallow over it arain and push ** into the dual of the forge, letting it remain until cold.
If these directions are followed with dexte*nty you will have the temper alike from edge to back ; a^d the edge will be the best you ever saw, as Davy Crockett used to say " It will jump higher, dive deeper," shave mor< hogs, bend farther without breaking, and give better satisHction than all other knives put together.
It works equally well on drawing-knives and pther thin tools; and for trap-springs which are to be s*t on dry ground; but if set in water, "pop goes the weasel" the first time the trap is sprung ; but the following is ^-ie plan for tempering springs for general trapping.
2. TRA.P SPRINGS— To Temper.— For tempering o^t steel trap springs, all that is necessary ia to heat them in the d^^k jasH that you may see it is read, then cool them in lukewarm watef. This is a short recipe, but it makes long-lasting springs.
The reason why darkness is required to temper sp«-\nga is that a lower degree of heat can be seen in the night- than by day-light : and the low heat and warm water giv? xht desired temper.
SILVER PLATING— For Carkiage Work —First, let the i irts which are to receive the plate be filed very smooth ; then apply over the surface the muriate of zinc, which is made by dissolving zinc in muriatic acid ; now hold this part over a dish containing hot soft-solder, (pewtei solder is probably the softest) and with a swab apply the solder to the part, to which it adheres ; brush off all superfluous solder, so as to leave the surface smooth ; you will now take No. 2 fair, silver plate, of the right size to cover the surface of the part prepared with solder, and lay the plate upon it, and rub it down smooth with a cloth which is moistened with oil, then, with a soldering-iron, pass slowly over all the surface of the plate, which melts the solder underneath it, and causes the plate to adhere as firmly as the solder does to the iron ; then polish the surface, finishing with buckBkin.
IRON— To Prevent Welding.— Where it is desired to weld two bars of iron together, for making axletrees or other purposes, through which you wish to have a bolt-hole, without punching out a piece of the iron, you will take a piece of wet pasteboard, the width of the bar and the length you desire not to weld, and place it between the two pieces of iron, and hold them firmly upon the pasteboard while taking the heat, and the iron will weld up to the pasteboard, but not where it is ; then open the hole, with swedge and punch, to the desired size.
In this way blacksmith's tongs may be relaid, without tbe trouble of cutting the joints apart and making a new jaw. Simply fit two pieces of iron, the thickness you wish to add to the jaw of the tongs, have them of the right length and width also, then take them both between the jaws and heat them so you can pound them together, that they will fit closely for a weld ; now put a piece of the wet pasteboard between the pieces which you are to weld, having the handles of the tongs strand sufficiently apart that you may put on a link or ring to hold all firmly ; then put into the fire, and take a good welding heat ; and yet they do not weld where the paper was between them ; if they stick a little at the end, just put them on the swedge and give them a little tap with the hammer, and they will fly right apart as nice as new. I am told that the dust from the ground or floor of the blacksmith-shop is as good as the pasteboard, y^jt I have not seen that tried ; but I know there is no mis-
(!AST-IRON— To Casb-Hahdkn.— Cast-iron may be cas* hardened by heating to a red heat, and then rolling it in a conilx)8ition composed of equal parts of Prussiate of potash, sa4' ammoniac, and saltpetre, all pulverized and thoroughly mixeti; Ihen plunged, while yet hot, into a bath containing 2 ozs. of ih« Prussiate, and 4 ozs. of the sal-ammoniac to each gal. of cold water. — Scientific Artisan.
Sleigh-shoes have been drilled, by this plan, in five minutes, after a man hud spent half a day in drilling onefourth of an inch, into it. It is applicable to any article which can be heat without injury.
WROUGHT - IRON— To Case - Harden.— To case-harden wrought-iron, take tlie Prns.siate of potash, finely pulverized, and roll the article in it, if its shape admits of it, if not, sprinkle the powder upon it freely, while the h-on is hot.
This is applicable to iron-axletrees, by heating the axletfce and rolling the bottom of it in the powder, spread out for that purpose, turning it up quickly and pouring cold water upon it, getting it into the tub of cold water as quick as possible. They will wear for years, without showing wear.
2. Welding a Small Piece op Iron Upon a Largb One, with Only a Light Heat. — It is often desirable to weld a small bit of iron upon a large bar, when the largo piece must be heated equally hot as the small one. Tb save this :
powder dry for use.
When you want to perform the operation, just bring the large piece to a white heat, having a good welding heat upon the small slip ; take the large one from the fire, and sprinkle some of the powder upon the place, and bring th«
without the powder.
BRONZING— For Iron or WooD.—First, make a black paint ; then put in a little chrome-yellow, only sufficient to give it a dark-green shade ; apply a coat of this to th« article to be bronzed ; when dry, give it a coat of varnish ; and when the varnish is a little dry, dust on bronze by dipping a piece of velvet into the bronze and shaking it upon the varnish ; then give it another coal of varnish, and when dry, all is complete.
Cast-iron bells, which are now being extensively introduced to the farming community, will be much improved ia their appearance by ihu^ bronzing, and also protected from rttst, without injury to itt sound. Iron fences around yards, porches, verandas, &c., wii^ be much improved by it. It may also be aj)plied to wood, if desired.
TRUSS SPRINGS.— Directions for Blacksmiths ro Make — Better than the Patent Trusses. — After having tried the variotis kinds of trusses, over two years, having to wear one upon eaoh side, I gave them all up as worse than useless.
TRtrSS SPRING.
Then they were bent to suit the shape of the body, and to press upon the body only sufficient, after the pads are put on, to h-old hsKk. that which would otherwise protrude. The pad upon the back end of the spring I make of sole-leather, covered with cotton or linen clott, having stuffed in a little batting to raaka U rest as easy as possilble. The front pad I make by having a piece of wood turned the shape and size of a small hen's egg, fiivwiog it through the center lengthwise, putting two screws into it tliroiigh the holes represented in the end of the spring for that purp(»e. The back pad is secured by one screw only. The spring is oil^d, then covered with sheep skin, to prevent rusting. Thta it ifl secured aroimd the body with a leather strap and
buckle, or with a piece of cloth sewed into a string of suitable width to sit easy where it bears upon the hip, in passing to tie upon the other end of the spring, just back of the front pad. The bend which is given the spring, before it is bent to the shape of the body, gives it room to rise when the leg is raised, without lifting the pad from its position, saving the necessity of another strap to pass around under the thigh, as with the patent truss, which is very annoying to the wearer. Make the springs r»r Bpring-steel, about i or | of an inch in width, and about 1-16 in thickSess, and of sufficient length to have a bearing just short of the spine.
Dissolve the asphaltum and rosin in the turpentine ; then rub up the lamp-black with linseed-oil, only suffiaient to form a paste, and mix with the others. Apply with a brush.
Put all into a suitable kettle, except the turpentine, over a slow fire, at first, then raise to a higher heat until all are melted ; now take from the fire, and when a little cool, stir in the spirits of turpentine and strain through a fine cloth. This is transparent ; but by the following modifications any or all the various colors are made from it.
tiupcntine i pt.
Melt the asphaltum in the turpentme ; rub up the blue with a little of it, mix well and strain ; then add the whoU to one pint of the first^ above.
ous colors. Apply with a brush.
GOLD LACQUER FOR TIN.— Transparent, All Coir ORS. — Alcohol in a hask i pt. ; add gum shellac 1 oz. ; turmeilo ^ oz. ; red-sanders i oz. Set the llask in a warm jAace, shake frequently for 13 hours or more, then strain off the liquor, rinse the bottle and return it, corking tightly for use.
When this varnish is used, it must be applied to the work freely and flowing, or, if the work admits ef it, it may b<i dipped into the varnish, and laid on the top of the stove ta dry, which it will do very quickly ; and they must not )e rubbed or brushed while drying ; or the article may be hot when applied. One or more coats may be laid on, as the ioloT is required more or less light or deep. This is applied to lanterns, &c. If any' of it should become thick from evaporation, at any time, thin it with alcohol. And by the following modifications, all the various colors are obtained.
only a slight change of materials or combinations.
LACQUER FOR BRASS.— Transparent.— Turmeric root g-'ound tine, 1 oz.; best dragon's blood i dr.; put into alcohol 1 pt.; place in a moderate heat, shake well for several days. It must be strained through a linen cloth and put back into the buttle, and add powdered gum shellac 3 ozs.; then keep as be*
Lacquer is put upon metal for improving its appearaoce and preserving its polish. It is applied with a brush wboD the metal is warm, otherwise it will not spread evenly.
IRON — To Tin fou Solderlng ok Other Porposes. — Tak« any quantity of muriatic acid and dissolve all the zinc in it thai it will cut ; then dilute it with one-fourth as much soft water ai of acid, and it is ready for use.
This rubbed upon iron, no matter how rusty, cleanses it and leaves some of the zinc upon the surface, sa that soldei ."eadily adheres to it, or copper as mentioned below for coppering iron or steel,
solution and it immediately exhibits a copper surface.
Lettering on polished steel is done in this way; flower' ing or ornamenting can also be done in the same way Sometimes dilute muriatic acid is used to clean iho surface; the surface must be clean by filing, rubbing, or acid j then cleaned by wiping off.
COPPER — To Tin for Stew-Dishes oh Other Pcrposes.— Wash the surface of the article to be tinned, with sulphuric acid ; and rub the surface well, so as to have it smooth and fre€ of blackness caused by the acid ; then gprinkle calcined and finely pulverized sal-ammoniac upon the surface, holding it ovei a fire where it will become sufficiently hot to melt a bar of solder which is to be rubbed over the surface ; if a stew-dish pufl Ihe solder into it and swab it about when melted.
You will wipe off any surplus solder, and also for the purpose of smoothing the surface, by means of a tow or colton swab, tied or tacked to a rod. In this way any dish oi copper article may be nicely tinned.
BOX-IIETAL — To Make for Machtnery.— Copper 4 parts; lead 1 part — ziuc is sometimes substituted for the lead — eithet makes a durable box for journals.
part , lead 1 part.
BKITANNIA— To Use Old, instead op Block Tin, in Soi,DER. — Take old Britannia and melt it; and while Lot sprinkle sulphur over it and stir for a short time.
Heat the tin quite hot over a stove or heater ; then with & sponge wet with the mixture, washing off directly with elean water. Dry the tin ; then varnish it with Demar?arnish.
2. Tinning Flux — Improved. — It has been customary for tinners to use the muriate of zinc only ; but if you take 1 lb. of muriatic acid and put in all the zinc it will cut ; then put in 1 oz. of sal-ammoniac, ;;-sa will have no more trouble with old dirty or greasy seams.
equal amount of soft water.
3. Liquid Glue, for Labeling Upon Tin. — Boiling water one quart ; borax, pulverized, two ounces ; put in the borax ; then add gum shellac four ounces, and boil until dissolved.
culty entirely,
SCOURING LIQUID— For Brass, Doob-Knobs, «&c.— OU ©f vitrol 1 oz. ; sweet oil i gill ; pulverized rotton stone 1 gill ; rain-water 1^ pts. ; mix all, and shake as used.
Apply with a rag, and polish with buck-skin or old woolen. This makes as good a preparation as can be purchased, and for less than half the money. It does not give a coating, but is simply a scourer and polisher. The following gives it a silver coating :
SILVERING POAVDER— For Copper or worn Plated Goods. — Nitrat*, of silver and common salt, of each 80 grs. : cream of tartar 8i drs. ; pulverize fiiiely, mix thoroughly and botU« for UA&
When desired to re-silver a worn spoon or other articla, first clean them with the " Scouring Liquid " ; then moisten a little of the powder and rub it on thoroughly with a piece of buck-skin. For Jewelry, see " J ewelry DepaitEwnt."
keep corked for use.
Directions. — Plug both er.Js of the barrel, and let the plugs stick out three or four inches, to handle by, and also to prevent the fluid from en( -ring the barrel, causing: it to rust; polish the barrel perfectly; then rut) it well with quick-lime by means of a cloth, which removes oil or grease; now apply the brt ^ning fluid with a clean white cloth, apply one coat and set in a warm, dark place, until a red rust is formed over the whole surfacs, which will require, in warm weather, fro'^aa ten to twelve hour^s, and in cold weather, from fifteen to twenty hours, or until the rust becomes red ; then card it down with a gun-raaker's card and rub off with a clean clath ; repeat the process until tht color suits, as each coat gives a darker shade.
2. Quicker and le^^s Laborious Process. — While in Evansville, Ind., I solii one of my books to C. Keller, a man who carries on gin.smithing, extensively. He gave me the following," which ^e was using, and says it makes & dark brown, with but lit4e labor compared with the first.
Bublimate 1 oz. ; and add 1 oz. of spirits of nitxe. Have the barrel bright and put ou one coat of the mixture ; and in 1 hour after, put on another, and let the barrel stand 12 hours ; then oil it and rub it with a cloth, of course having the ends of the bar rel tightly plugged, as in the first case.
But Mr. Sutherland, the gunsmith of this city, says the brown from this recipe will soon rub off; none being permanent unless carded down properly, as directed with th« first recipe, that mixture being also superior.
3. Brownenq for Twist Barrels. — Take spirits of nitre i oz. ; tincture of steel f oz. ; (if the tincture of steel cannot be obtained, the unmedicated tincture of iron may be used, but it is not so good) black brimstone i oz. ; blue vitriol i oz. ; corrosive sublimate i oz. ; nitric acid 1 dr. or GO drops ; copperas J oz. ; mix with 1^ pts. of rain water, keep corked, also, as the other, and the process of applying is also the same.
You will understand this is not to make an imitation of twist barrels, but to be used upon the real twist barrels, which brings out the twist so as to show ; but if you use the first upon the real twist barrels, it will make the whole surface brown like the common barrel.
CASE-HARDENING— For Lock-work.— Take old boots and shoes and lay them on a fire, and burn them until charred ; now put them into a clean kettle and pulveiize them coarsely, while hot ; be careful not to get any wood coals mixed with ihem.
Directions. — Take the pulverized leather and place in a iheet-iron box, placing the articles to be hardened in the centre of the box, or amongst the pulverized leather, and cover with a sheet-iron cover ; or make the box so as to «hut up ; now blow up a fire of very dry charcoal ; the coarser the charcoal the better ; then open the fire and place the closed box in the centre, cover it up and let stand fi"om forty to sixty minutes, not blowing; but if the coals burn off and leave the box exposed, you will put on more ; at tlie expiration of the time, take the box and pour its conteuU It to clean, moderately cool or cold water — never use warm w^ter ; these articles will now be found very hard, and will eftsily break ; so you will draw the temper to suit.
BROKEN SAWS— To SIend Permanently —Pure silver 19 flirts ; pure copjier 1 part ; pure brass 2 parts ; all are to be Kied into powder and intimately mixed. K the saw is not retently broken, apply the tinning preparation of the next recipe.
Place the saw level upon the anvil, the broken edges in close contact, and hold them so ; now put a small line of the naixture along the seam, covering it with a larger bulk of powdered charcoal; now, with a spirit-lamp and a jewelcrs' blow-pipe, hold the coal-dust in place, and blow sufficient to melt the solder mixture ; then with a hammer set the joint smooth, if not already so, and file away any superfluous fto.dar ; and you will ba surprised at its strength. The heat upon a saw does not injure its temper as it does other tools, from the fact that the temper is rolled in, in place of by heat and water.
TINNING — SuPEKioR TO the Oi-d Process. — Take first, th* same as the old way ; that is, muriatic acid 1 pt., and as much pure block or sheet zinc as it will cut, in an open dish, a bowl^ or something of that character, as much heat is set free and bottles are often broken by it ; now take sal-ammoniac 4 ozs.; pulverize it and add to the other, and boil 10 minutes in a copper betlle^bear in mind, only copper is to be used to boil in.
VARNISH AND POLISH FOR STOCKS— German.— Gum shellac 10 ozs.; g\im sandarach 1 oz. ; Venice turpentine 1 drachm ; alcohol 95 to 98 proof 1 gal.; shake the jug occasionally for a day or two, and it is ready for useAfter using a few coats of this, you can have a Germanpolish, by simply leaving out 8 ozs. of the shellac j and a coat or two of the polish makes an improvement on the varnish, and does not require the rubbing, that it would if the full amount of shellac was used, in the last coat or two. It is recommended also to put upon cuts, sores, &c., burM excepted.
GALVANIZING— Without a Battery.— Dissolve cyanuret of potassium 1 oz., in pure rain or snow water 1 pt., to which add a 1 dr. bottle of the chloride of gold, and it is ready to use. Scour the article to be plated, from all dirt and grease, witlt wbitiug, chalk, or rotten stone, pulverized, and put in alcohol^
JEWELERS DEPAKTMENT.
a?lng a good brush — or the " Polishing Compouud," No. 3 ; if mere are cracks, it maj^ be necessary to put the article in a solulion of caustic potash — at all events, every particle of greaso and iirt must be removed ; then suspend the article to be plated ia Vlie cy-inuret of gold solution, with )i small strip of zinc cul ibout the.width of a common knitting-needle, hooki«g the top !)ver a stick which will reach acrwss the top of the jar holding iic solution.
Every five to ten minutes, tlie article should be taken out and brushed over with the scouring preparation ; or on smooth surikces it may be rinsed oif and wiped with a piece of cotton cloth, and return until the coating is sufficiently heavy to suit.
When the plating fluid is not in use, bottle it, keeping it corked, and it is always ready for use, bearing in mind that it is as poison as arsenic, and must be put high, out of the Tvay of children, and labeled — J-'akon, although you will have no fears in using it ; yet accidents might arise, if iti nature were not knowu. The zinc strip, as far as it reaches into the fluid, will need to be rubbed occasionally, until it is bright.
2. Galvanizing "With a Shilling Battery. — I have found some persons who thought it much better to use a simple battery, made by taking a piece of copper rod about three-eighths of an inch in thickness, and about eighteen or twenty inches long, and bend it, as seen in the accompanying cut :
SHILLING BATTERY.
The rod should be about 4 or 5 inches in the circle or bend, then run parallel, having 5 strips of sheet zinc, an inch wide and B to 8 inches long, bent in their centre around the copper, with a rivet throuf,h them, close to the rod, as shown above ; these strips of zinc are to be placed into tuinljlors, the rod resting ou top of the tumblers, which are to be nearly filled witji rain water; then pour into each tumbler a little oil of vitriol, until yoo see that it begins to work a little on llie zinc.
The article to be plated is to be suspended upon the strtj of zinc, as represented upon the long end of the rod, wbicls is to be placed as before spoken of, in a jar containing the gold solution, instead of having it upon the stick spoken of when plating without the battery. And all the operations are the same as before described.
To use, for rings, or other smooth-surfaced jewelry, wet a bit of cloth with the compound, after having skaken it, and rub the article thoroughly ; then polish by rubbing with a silk handkerchief or piece of soft buck-skin. For articles which are rough-surfaced, use a suitable brush. It u applicable for gold, silver, brass, britannia, plated goods, &o.*
CHOLIC — Cure for Horses or Persons. — Spirits of turpentine 3 ozs.; laudanum 1 oz.; mix, and give all for a dose, by putting it into a bottle with half pint of warm trater, which prevents injury to the throat. If relief is not obtained in one hour, repeat the dose, adding half an ounce of the best powdered aloes, well dissolved together, and have no uneasiness about the result.
Symptoms. — The horse often lies down, suddenly rising again, with a spring; strikes his belly with his hind feet, stamps with his fore feet, and refuses every kind of food, &c. I suppose there is no medicine in use, for cholic, either in man or horse, equal to this mixtiu-e.
For persons, a dose would be from 1 to 2 tea-spoons — children or weak persons, less, according to the urgency of the symptoms, to be taken in warm water or warm tea.
I have been familiar with it for about five years, and kno-w that it has been successful in many cases — all where it has been used. Many think it the best cholic remedy in the world.
2. Anothek.— Laudanum i oz.; sulphuric ether 1 oz. Mix, and for a horse, give all at a dose, in warm water as above. Dose for a person, as the first.
dose, except one, and in that case by repeating the dose thirty miautes after the first. There is no question but what it is good, and some would prefer it to the turpentine J know it is valuable.
BOTS — b'uRE Remedy — When a horse is attacked with bots, it may be known by the occasional nipping at their own sides, and by red pimples or projections on the innei surface of the upper lip, which may be seen plainly bj turning up the lip.
FmsT, then, Like new milk 2 qts.; molasses 1 qt.; and give ths borse the "whole amount. Secokd, 15 minutes afterwards give verr warm sage tea 2 qts. Lastly, 30 minutes after the tea, you will giv*; of currier's oiJ i pt , (or enough to operate as physic.) Lara has been used, when the oil could not be obtained, with the same succes*.
The cure will be complete, as the milk and molasses cause the bots to let go their hold, the tea puckers them up, and the oil carries them entirely away. If you have any doubt, one trial will satisfy you perfectly. In places where the currier's oil cannot be obtained, substitute the lard, adding three or four ounces of salt with it ; if no lard, dissolve a double handful of salt in warm water three pints, and give all.
RING-BONE AND SPAVINS— To Ccre.— Egyptiacum and wine vinegar, of each 2 ozs.; water of pure ammonia, spirits of turpentine, and oil of origanum, of each 1 oz.; euphorbium and cantharides, of each i oz.; glass made' fine and sifted through gauze 1 dr.; put them in a bottle, and when used let them be well shaken. This is to be rubbed upon the bone enlargement with the hand or spatula, for half an hour each morning, for six or seven mornings in succession. Then let him run until the scab comes oft" of itself without scraping, which mjures the roots of the hair. Then repeat as before, and follow njt tor 3 or 4 times blistering, and all bone enlargements will be te absorbed, if not of more than a year or two's standing.
It is also good for callous sinews, and strains of long standing, spavins, big-head, &;c., but if there are ring-bones or spavins of so long standing that this does not cause their c are, you will proceed as follows :
ready.for use, always shaking well as you use either prepaiution. Now clip the hair and prick the bone or callous part as full of holes as you can with a pegging-awl, which, is just long enough to break through the callous part only Or a better way to break up this bony substance is to have a handle like a pegging-awl handle, with three or four awls in it, •ihen tap it in with a stick and give it a wrench at the ?ame time, which does the hurting part with more speed. Thii dona, batlie the part witli vinegar, until the blood stopa flowing ; then apply the double compound as at first, for four or five mornings only, repeating again if necessary; and ninety-nine out of every hundred ring-bones or spavins will be cured ; and most of them with only the first prcparatioa. The Egyptiacum is irfade as follows :
3. Take verdigris and alum in powder, of each 1| ozs.; blue vitriol, powdf reef, i uz.; corrosive sublimate, in powder, ^ oz.; vinegar 21^ ozs.; honey i lb.; boil over a slow fire until of a proper consistence. When used it must be stirred up well, as a sediment wUl deposit of some of the articles.
If the hair does not come out again after using the last blister, use the " Good Samaritan Liniment" freelj, on the part; but the first will never disturb the growth of hair. It is best always to commence this kind of treatment early in the season, so as to effect a cure before cold weather 'tomes OD.
4. O. B. Bangs' Cukb for Reng-Bone and Spavin. — Take of cantharides pulverized ; British oil ; oils of origanum and amber ; and spirits of turpentine, of each 1 oz.; olive oil ^ oz.; oil of vitriol 'i drs.; put all, except the vitriol, into alcohol, stir the mixture, then slowly add the vitriol and continue to stir unti? the mixture is complete, which is known by its ceasing to smoke. Bottle for use.
Directions. — Tie a piece of sponge upon a stick and rub *bo preparation by this means, upon the spavin or ring-bone ^s long as it is absorbed into the parts ; twenty-four hours after, grease well with lard; and in twenty-four hours more, rash off well with soap-suds. Mr. Bangs lives at Napoleon, Mich., and has sold books for me nearly two years. He Bays one application will generally be sufficient for spavins, but may need two ; ring-bones always require two or thr«« applications, three or four days apart, which prevents tlia load of hair; if not put on oftener than once in three oc
toTii days, the hair not coming out at ail. Said to cure wind-galls, splints, &c. He obtained five dollars for curing a neighbor's horse of ring-bone, with this preparation ; stopping all lameness, but not removing the luiup.
Apply, by washing off and using lard afterwards, as above directed, washing also forty-eight hours after; and when dry, apply the first liniment once or iwice, according to directions. The object of this last is to opea the pores of the skin, and soften the lump.
6. Ring-bone Remedy. — Pulverized cantharides, oils of spike, origanum, amber, cedar, Baibadoes tar, and British oil, of each 2 ozs. ; oil of wormwood 1 oz. ; spirits of turpentine 4 ozs. ; common potash ^ oz. ; nitric acid 6 ozs. ; and oil of vitriol (sulphuric acid) 4 ozs. ; lard 3 lbs.
Directions. — Melt the lard and slowly add the acids, Btir well and add the others, stirring until cold. Clip off the hair and apply by rubbing and heating in j in about three days or when it is done running, wash off with suds and apply again. In old cases it may take three or four weeks, but in recent cases two or three applications have cured. It has cured long standing cases.
7. Rawson's Ring-bone and Spavin Cure.— Venice turpentine and Spanish-flies, of each 2 ozs. ; euphorbium and aqua ammonia, of each 1 oz. ; red precipitate i oz. ; corrosive sublimate i oz. ; lard H lbs. Pulverize all and put into the lard simmer slowly over coals, not scorch or burn, and pour off free of sediment.
Directions. — For ring-bones, cut off the hair and rub the ointment well into the lumps once in forty-eight hours. For spavins, opce in twenty-four hours for three mornings, has perfectly cured them. Wash well, each application, with euds, rubbin/!^ over the place with a smooth stick to sqeez out a thick yellow matter.
Mr. Rawaon, of Rawsonville, Mich., has cured some exceedingly ijad cases of ring-bones, one as thick as a man' . arm ; and spavins as unpromising in size. If properly cooked jt will foam like boilins' sugar.
Shave oflF the hair the size of the bone enlargement; then grease all around it, but not where the hair is shaved oflf; this prevents the action of the medicine, only upon the spavin ; now rub in as much of the paste as will lie on a three cent piece only, each morning for four mornings only ; in from seven to eight days the whole spavin will come out ; then wash out the wound with suds, soaking well, for an hour or two, which removes the poisonous effects of the uedicine and facilitates the healing, which will be done by ny of the healing salves ; but I would prefer the green ointment to aay other in this case.
Mr. Andrews, late of Detroit, who during his life, knew a good horse, and also desired to know how to take good care of them, did not hesitate to pay three hundred dollars for this recipe after seeing what it would do ; he removed a spavin from a mare's leg with it, and she afterwards won him more than the expense.
10. Bone-Spavins — Norwegian Cure. — S. B. Marshall, the Champion Horse-Shoer, and Farrier, of White Pigeon, Mich., obtained this plan of an old Norwegian Farrier, and also his plan of curing poll-evil, which see, and assures me that he has been very successful with them. I obtained them of him for the purpose of publication, and sincerely think I can recommend them to all who need them :
Take dog's grease i pt.; best oil ot origanum H ozs ; pnlver Ized cantharides i oz. Mix, and apply each momifig, for three mornings ; heatintc it in with a hot iron each time ; then skip 3 mornings, and app^y again, as before, until it has been applied 9 times ; after which wait about 10 days, and if it is not aU gvuia, go over again in the same way
He says it does not remove the hair, but that it cures the largest and worst cases. He gives a test for pood oil of origanum, saying that much of it is reduced with turpentine ; and if so reduced, that it will spread on the skin, like turpentine ; but if good, that it does not spread on the skin, but stands, like other oil, where a drop is put on. I am not certain about the genuineness of this test ; yet I find quite a difference in the spreading of the oils ; for that which is known to contain turpentine spreads fast and freely; whilst that which is believed to be pure, spreads very slowly, yet does finally spread. The pure is of a dark wine color, whilst the poor is of a lighter shade, and some what cloudy.
verized i oz.
Apply once in six to nine days only — removes the lump of spavins, splints, curbs, &c., if of recent occurrence ; and tlie man of whom I obtained it, says he has scattered pollevils before breaking out, with cedar oil, alone.
12. Another. — Alcohol and spirits of turpentine, of each i pt. ; gum camphor, laudanum, and oil of cedar, of each 1 oz. ; oila of hemlock and rhodium and balsam of fir, of each i oz. ; iodine 1 dr. ; mix.
Apply night and morning, first washing clean and rubbing dry with a sponge ; then rub the liniment into the spavin with the hand. It causes a gummy substance to ooze out, without injury to the hair — has cured ring-bones, also removing the lumps in recent cases. It cured the lameness in a c&se of three years standing.
1-3 2r:.DfT AND Spavin Liniment. — Take a large mouthed bctlie and put inio it «il of origanum 6 ozs. ; gum camphor 2 ozs. ; mercivrial oiatment 2 ozs. ; iodine ointment 1 oz. ; melt by putting the bottle into a kettle of hot water.
Apply it to bone-spavins or splints twice daily, for four or five days. Th« lameness will trouble you no more. I have had men cure their horses with this liniment and remark that this recipe alone was worth more than the price of the book,
14. Bog-Spavin and Wind-Gall Ointment, also good fob CuKBS, Splints, Hinq-bones, and Bone-Spavin. — Take pulverUed cantharides 1 oz. ; mercurial ointment 2 ozs. ; tincture of
!Mix well, and wlien desired to apply, first cut oflf the hair, wash well and anoint, rubbing it in with the hand or glove, if preferred. Two days after, grease the part with lard, and in two days more, wash oflF and apply the ointment again. Repeat the process every week, as long aa necessary.
SWEENY — LrNTMENT. — Alcohol and spirits of turpentine, of «ach 8 ozs. ; camphor gum, pulverized cantharides, and caps! cum, of each 1 oz. ; oil of spike 3 ozs. Mix.
Perhaps the best plan is to tincture the capsicum first and use the tincture instead of the powder, by which means you are free of sediment ; bathe this liniment in with a hot iron. The first case has yet to be found where it has not cured this disease when faithfully followed.
This last has cured many cases of sweeny, and also kidney complaints, 'known by a weakness in the back, of horses or cattle. Bathe the loins with it ; and give one to two tsible-spoons at a dose, daily.
rOLL-EVIL AND FISTULA— PosixrvE Cure.— Common potash i oz. ; extract of belladona i dr. ; gum arable i os. DisBolve the gum in as little water as practicable; then having pulverized the potash, unless it is moist, mix the gum water with it and it will soon dissolve ; then mix in the extract and it is ready to use ; and it can be used without the belladona, but it is more painful without it, and does not have quite as good an effect.
Directions. — The best plan to get this into the pipes is by means of a small syringe, after having cleanseo the soro with soap-suds ; repeat once in two days, until all the ca*lous pipes and hard fibrous base around the poll-evil or fistula, is completely destroyed. Mr. Curtis, a merchant of Wheaton, 111., cured a poll-evil with this preparation, by only a single application, as the mare estrayed and was not found for two months — then completely sound ; but it will generally require two or three applications.
This will destroy corns and warts, by putting a little of it upon the wart or corn, letting it remain from five to t«n minutes, then wash off and apply oil or vinegar, not squeeaing them out, but letting nature remove them.
9. Potash, .x» Make.— It rou cannot buy the potash, called ^or in the Iju.^ recipe, you oin make it by leachiiig best wood ashes and boiling down the lye to what is called black salts, and continuing the heat in a thick kettle until they are melted; th<s beat burn^ out the black impurities and leaves a whitish'gra/ lubntance, called potash.
This potash, pulverized and put into all the rat holes tbout the cellars, causes them to leave in double quick time, w mentioned in the " Rat Exterminator." The black salta will do about as well for rats, but is not quite so strong. They get their feet into it, which causes a biting worse than their own, and they leave without further ceremony.
Potash making in timbered lands is carried on very extensively ; using the thick, heavy potash-kettle to boil and melt in ; then dipping it out iato three and five pail ironkettles to cool.
3. Poll-Evil and Fistula — Norwegian Cuke. — Cover the head and neck witJi two or three blankets; have a pan or kettle of the best warm cider vinegar; holding it under the blankets; then steam the parts by putting hot stones, brick, or iron, into the vinegar, and continue the operation until the horse sweat freely; doing this 3 morniuga and skipping <J, until 9 steaminghave been accomplished.
Mr. Marshall says, the pipes, by this time, will seem to have raised up and become loose, except the lower end, which holds upon the bone or tendons, like a sucker's mouth ; the apparent rising being caused by the going down of the swelling in the parts ; now tie a skein of silk around the pipes and pull them out ; washing the parts with weak copperas water until the sore heals up and all is well. He told me that he cured, in this way, a horse which had interfered until a pipe had formed at the place of interference, upon the leg, that when drawn out was as long as his linger. See the " Norwegian Cure for Bone-Spavin."
Fill a goose-quill with the powder and push it to the hot torn of the pipe, having a stick in the top of the quill, so tnat you can push the powder out of the quill, leaving it at the bottom of the pipe ; repeat again in about four days, and in two or three days from that time you can take hold df the pipe and remove it, without trouble.
5. Poix-Erih, TO Scatter.— Take a quantity of mandrake •■oot, mash, and boil it ; strain and boil down until rather thick ; then form an ointment by simmering it Avith sufficient lard for that purpose.
Anoint the swelling oucc a day, for several days, unti) well. It has cured them after they were broken out, by putting it into the pipes a few times, also anointing around the sore.
7. Another. — Corrosive subli lale the size of a common beau-, pulverized and wrapped in tissue paper, and pressed to the bottom of the ])i))es, leaving it in eight days, tlien take out, and applying the blue ointment, (kept by druggists,) has cured them. Or:
8. Anotiter. — Arsenic, the Hize of a pea, treated in the same way, has cured tlie same disease. But if the Norwegian plan wiu work as recommended, it is certainly the best ot all.
I found one man, also, who had cured poll-evil by placing barrel of water about fifteen feet high, on a platform, upon two trees — aumiuistering a shower bath daily upon the sore ; drawing the water by a faucet, through a diuner horn placed little end down ; tying the horse so as to keep him in position until the water all runs out Fifteen or twenty baths cured him, but ifbroke out again the next season, when a few more baths made a final cure.
LOOSENESS OR SCOUTJING IN HORSES OR CATTLE— In Use ovtsk Seventy Yeaus. — Tormentil root, powdered. Dose lor a horse or cow 1 to 1 J <>z. It may be stiiTed in 1 pt. of milk and given, or it may be sloei^ed in li pts. of milk then given from y to 5 limes daily until cured.
It has proved valuable also for persons. Dose for a person would be from one-half to one tea-spoon steeped in milk j but if used for persons I should recommend that half ad much rhubarb be combined with it.
An English gentleman from whom it was obtained, had been familiar with its use nearly eighty years, and neve? knew a failure, if taken in any kind of seasonable time. The tormentil, or scptfoil, is an European plant, and very 46tringent.
gemcral favor.
i). Scouns AST> PiN-WoKMs OK lIousKS AND Cattle. — Wl.ite ttt;h baiK. biirut U) asiies aud luade iulo rather -^ stnjng i3'e ; then mix i pt. of it with warm water 1 i>t., and give ail, 2 or 3 times daily.
^V!lenever it becomes certain that a horse or cow ia troul)led witii pin-worm.s, by their pa.ssiug from the bowels, it i« best to administer the above, as they arc believed to be the cause, generally, of scours, and this remedy carries off the worms, thus curing the inflammation by removing the cause. '
boes-wax 4 ozs. ; lard 8 ozs. ; honey 2 ozs. Idelt these articles slovviy, gently bringing to ;i boil ; and as it begins to boil, remove I'rom the fire and slowly add a little less than a i)int of Bpiriis of tnrpeniine, stirring all the time this is being added, and stir until cool.
This is an extraordinary ointment for bruises, in flesh or hoof, broken knees, galled backs, bites, cracked heels, &c,, &c. ; or when a horse is gelded, to heal and keep away flies, [t is excellent to take fire out of burns or scalds in human flesh also.
CONDITION POWDERS— Said to mo St. John's.— Fenu greek, cream of tjirtar, gentian, sulj)hur, saltpetre rosin, black aniiiao'ij-, and ginger, e([ual quaiUities of each, say 1 oz. ; all to be fiiTc'y pulverized ; cayenne, also fine, half the fpiautiiy of any one ot t!;e others, say ^ oz. Mix thorouglily?
It is use<l in yellow water, hide-bound, coughs, colds, distemper, and all other diseases where condition powders are generally administered. DosK — In ordinary cases give two tea spoons once a day, in ^'^od. In extreme cases give it twio daily. If these do not give as good satisfaction as St. John's or any other condition pov/der that costs more than double what it does to make this, then I will acknowledge that travel and study are of no account in obtaining iaformatioa.
2. Cathartic Condition Powder.— Garahoge, alum, salt petre, rosin, copperas, ginger, aioes, gum-myrrh, salts, and sail, and if the liorse is in a very low contiition, put in wormwood, all the same quantities, viz., 1 oz. each. Dose — One taV.> spoon in brin twice daily ; not giving any other grain for a fe*» day» ; then once a day with oats and other good feed.
This last is more applicable for old worn-down horsea ■which need cleaning out and starting again into new life j *nd in such cases, just the thing to be desired.
HORSE LINIMENTS— For Stiff-Neck from Polv Evils. — Alcohol one pint; oil of cedar, origanum, and gum-camphor, of each two ounces; oil of amber one ounce; ase freely.
2. ExGUsn Stable Lxnimknt — Vert Strnq. — Oil of spike aqua ammonia, and oil of turpentine, of each 2 ozs. ; sweet oil and oil of amber, of each l^ozs. ; oil of origanum 1 oz. Mix.
Call this good for any thing, and always keep it in the stable a.s a strong liniment; the Englishman's favorite for poll-evils, ring-bones, and all old lameness, inflammations, &c. ; if much inflammation, however, it will fetch the hair, but not destroy it.
3. Nerve and Bone Liniment. — Take beef's gall l qt. ; alcohol 1 pt. ; volatile liniment 1 lb. ; spirits of turpentine 1 lb. ; oil of origanum 4 ozs. ; aqua ammonia 4 ozs. ; tincture of cayenne i pt. ; oil of amber 3 ozs. ; tincture of Spanish-flies 6 ozs. ; mix.
BROKEN LIMBS — Treatment, Instead of Inhfhaiilt Shooting the Horse. — In the greater number of fractures it is only necessary to partially sling the horse by means of a broad piece of sail or other strong cloth, (as represented in the fl^re,) placed under the animal's belly, furnished with two breeci\ins9 and two breast-girths, and by means of ropes and pulley* attached to a cross beam above, he is elevated or lowered, as may be required.
allowed to touch the grouud or floor. The head-stall should be padded, and ropes re;iehin<r each way to the stall, ai well as forward. Many horses will plunge about for a time, but eoon quiet down, with an occasional exception ; when they become quiet, set the bone, splint it well, padding the splinta with batting, securing carefully, then keep wet with cold water, as long as the least inflammation is present, using light food, and a little water at a time, but may be giveu often.
SUPPORTING APPARATUS IN LAMENESS OF HORSES.
If he is very restive, other ropes can be attached to the corner rings, which are there for that purpose, and will afford much additional relief to the horse.
I knew a horse's tliigh to crumble upon the race-course., without apparent cause, which lost him the stake he would have easily won; he was hauled miles upon a sled, slung, and cured by his humane owner. Then let every fair means be tried, before you consent to take the life, even of a broken-legged horse-
WOUND BALSAM— FoK lIoiisE oil llmiAS Fi,Ksn.— Gua benzoin, in powiier, (J ozs.; balbam ol' UjIu, in jxjwucr, 8 ozs.; gum slorux 2 ozs.; ■liiinldnct'iisc, iu powder, 2 ozs.; gum myrrh, m powder, 2 ozs.; Sucotoriue aloes, in powder, cl ozs.; alcohol 1 gal. JSlix them all Ujgether and put tlieni in a digester, and give them a gentle heat for three or four days ; then strain.
Medka for healing fresh wounds in every part of the body,
!)artieularly those on the tendons or joint.s. It is frecjueutr y given internally along with other articles, to great advantage in all colds, flatulency, and in other debilities of the stomach and intestines. Every gentleman, or farmer, ought to keep this medicine ready prepared in his house, as a family medicine, for all cuts, or recent wounds, either . among his cattle or any of his family. Thirty or forty drops, on a lump of sugar, may be taken at any time, for flatulency, or pain at the stomach; and in old age, where Hature rctjuires stimulation. — Every Man His Own Farner.
GREASE-IIEEL AND C0M3I0N SCRATCHES.— To Curk. — Lye made from wood ashes, and boil white-oak bark in it until it is quite strong, both in lye and bark ooze ; when it is cold, H is reaiiy lor use.
First wash off the horse's legs with dish-water or castile Boap J and when dry, apply the ooze with a swab upon a Stick which is sufllciently long to keep out of his reach, aa he will tear around like a wild horse, but you must wet all ??ell once a day, until you see the places are drying up. The grease-heel may be known from the common scratcnes by the deep cracks, which do not appear in the common kind. Of course this will fetch off the hair, but the disease has been known to fetch off the hoof j then to bring on the hair again, use salve made by stewing sweet elder bark in old bacon ; then form the salve by adding a little rosin according to the amount of oil when stewed, about a quarter of a pound to each pound of oil.
mended fur grease heel
3. Common Scratcites. — Use sweet oil 6 oz.; borax 2 oz.; sugai of lead 2 oz.; mix, and apply twice daily, after wa,-iiiing off with dish-water, and giving time to allow the legs to dry.
Those plans have been used for years, by Geo. Cleniin, of Logansport, Indiana, and he assured me that the wore! oases will be cured, of either disease, in a very few days
good for common scratches, applied, as the last, after washing with dish-water and drying. This last can be tried first, as it is easily obtained, and if it does not succeed you ■will not fail witli the other.
SADDLE AND HARNESS GALLS— Bruises, Abkasioks, (fee. — Remedy. — White lead and linseed oil mixed as for paint, i» Almost invaluable in abrasions, or galls from the saddle or collar, or from any other cause, it will speedily aid the pai't in healing.
AppJiftd with a brush to the leg of a horse, the outer coating of liair and skin of which was torn off, caused it to heal and kave no scar. It is good for scratches and all Bores upon horses, or other animals, and equally good for men. It forms an air-tight coating, and soothes pain. Every farmer should keep a pot and brush ready for use. White lead is the carbonate of the metal, and when pure is very white. That having a greyish tint is impure, being generally adulterated. For use as a paint, a lead color is pfoduccd by adding lamp-black, and a drab or stone color, by adding burned umber
In applying it for scratches, first wash them clean with soap and water, then apply. Some persons prefer lamp oil. If that is used, you will mix both together until the oil as. Bumes a light straw color. "When the horse comes in at night, his legs should be washed perfectly clean and rubbed perfectly dry. Then apply the mixture, rubbing it well tf» the skin. Two or three applications are sufficient to effect a perfect cure, no matter how bad. the case may be. — Correspondence of the Country Gentleman.
To give confidence in this, I would say that a lady, at Lafayette, Ind., told me she cured herself of salt-rheum with white-lead and sweet oil only.
2. Another. — Alcohol and extract of lead, of each 2 ozs ; fioft water 4 ozs. ; spirits of sal-ammoniac 1 oz. ; white copperai i oz. Mix all and shake as used.
man or horse.
4. Another. — White ashes and spirits of turpentine, of each 1^ table-spoons ; black pepper, ground, 1 table-spoon ; lard to make 1 pt. of all, mix well and anoint
HEAVES. — Great Relief— Heaves, the common name for any difficulty in the breathing of a horse, is susceptible of great alleviation by attention to the character and quau tity of food to be eaten by the animal, as every onr knows. If a horse suffering from this disease, is allowed to distend his stomach at his pleasure, with dry food entirely, and then to drink cold water, as much as he can hold, he js nearly worthless. But if his food be moistened, and he b'o allowed to drink a moderate quantity only at a time, the disease is much less troublesome.
A still farther alleviation may be obtained from the use of balsam of fir and balsam of copaiba 4 ozs. each ; and mix with calcined magnesia sufficiently thick to make it iulo balls ; give a middling sized ball, night and morniug for a week or 10 days This gives good satisfaction, and is extensively sold by Eberbach & Co., druggists of this city.
2. Another. — An old Farrier assures me that lobelia one tea-spoon, once a day, in his feed, for a week, and then once a week ; that you can hardly tell whether a horse ever had the heaves or not.
3. Another. — H. Sisson, another Farrier, gives me a cure which somewhat resembles the ball first given under this head, and thus each one supports the other.
He takes calcined magnesia, balsam of fir, and balsam of eopaiba, of each 1 oz. ; spirits of turpentine 2 ozs. ; and puts them all into 1 pt. of best cider vinegar, and gives for a dose 1 table-spoon in his feed, once a day, for a week ; then every other day for 2 or 3 months.
4 Another. — Mr Bangs, highly recommends the following : Lobelia, wild turnip, elecampane and skunk cabbage, equal parts of each. Make into balls of common size, and give one for a dose, or make a tincture, by putting 4 ozs. of the mixture into 2 qts. of spirits ; and after a week put 2 table-apocns into their feed, once a dar foi h mouth or two-
%. Another. — Oyster e)u!lls 1 peck ; burn into lime and pulverize; mix a single handful of it -svith ^ gill cf alcohol, then inix it with the ouU each inoniing until all given.
This for bcllowa-heavcs has done very much good. Horseradish grated and put in with the feed has benefited. Cabbage, as common feed, is good to relieve, or any juicy food, like pumpkins, &c., &;c., will be found to relieve very jnuch. Farmers who have their horses always at home, can keep them comfortable with some of the foregoing directions j but broken-winded horses might as well be knocked in the head as to attempt to travel with them, expecting any satisfaotion to horse or driver.
" Commence with a piece of pork, say a cubic inch, chopped very fine, and mixed with the wetted grain or cut feed, twice a day for two or three days. Then from day to day increase the quantity and cut less tine, until there is given with each feed such a slice as usually by a farmer's wife is cut for frying — nearly as large as your hand, cut into tifteen or twenty pieces.
" Continue this for two weeks, and the horse is capable of any ordinary work with mt distress, and without showing the heaves. I have experience and observation for the past ten years as proof of the above." — [J. , of Burlington, Vt.
DISTEMPER— To Distinguish and Cure.— If it 18 thought that a horse hap the distemper, and you do not feel certain, wet up bran with rather strong weak lye — if not too strong they will eat it greedily ; if they have the distemper, a free discharge from the nostrils and a consequent cure will be the result, if continued a few days ; but il only a cold, with swellings of the glands, no change will be discovered.
letters, says:
" You have discovered, of course, that you cannot have uninterrupted winter riding with a horse shod in the ordinary way. The sharp points of the frozen mud will wound the frog of the foot ; and with snow on the ground, the hollow hoof soon collects A hard ball, which makes the footing very ineecure. But
these evils are remedied by a piece of sole leather nailed on uader the shoe— a protection to the hoof wliich makes a surpiiainj dillcreiice in tho confidence and 8ure-fook.-aness of the animar» step."
FOUNDER— REMEi>T.— Draw about 1 gal. of blood from th« neck; then drench the K')rse with linstied-oii 1 qt.; now rub th« fore legs, long and well, with water as hot as can be borne without scalding.
foundered on wheat, two days before tlie treatment began.
PHYSIC— Bam. fou IIouses.— Bai-badoes aloes from 4 to 5, or 6 drs., (according to tlie size and strength of the horse); tar trale of potassia 1 dr.; ginger and castile soap, of each 2 drs.; oL of anise <or peppermint 20 drops ; pulverize, and make all inta one ball with thick giun solution.
Before giving a horse physic, he should be prepared foj it by feeding scalded bran, in place of oats, for two days at least, giving also water which has the chill taken off, and continue this feed and drink, during it.^ operation. If it Bhould not operate in forty-eight hours, repeat Ixalf the dose.
2. PiiYSio FOii Cattle. — For cattle, take half only of the dose, above, for a horse, and add to it glauber salts 8 ozs.; dissolve all in gruel 1 qt., and give as a drench ; for cattle are not easily managed in giving balls, neither is their construction ad:ii)ted to dry medicine.
There is not the need of preparation for cattle, generally, an for horses, from the fact of their not being kept up to grain, if they are, however, let the same precautions be observed as in " Physic Ball for Horses."
Directions. — Lift the foot and drop a little of it upon the bottom. It will need to be applied only once or twice a week — as often only as they limp, which shows that the fool is becoming tender again. It kills the old hoof, and a ne\» one soon takes its place. Have no fears about tJie result ; apply the medicine as often as indicated, and all is eaf'c.
Wasli tliG eye freely, two or three times daily. But I f)refer the "Eye Water" a§ prepared for persons ; and alloTV me here to say that what is good for man, in the line of medicine, is good for a horse, by increasing the dose to cor respond.
TA^MINGr — Principles Applied to Wn.D and Yrcious Horses. — I have thought, in closing up this D* partment, that I could not devote a page to a better pui pose than to the so-called secret of taming. For it is a secret, but it lies in a different point from what is generally believed, which I will attempt to show.
Several persons are advertising books for taming wild horses, and other persons fire going about teaching the art to classes in private. Probably the pupils get their money's worth. But, why do so many fail ? The whole secret lies ill this, that mani/ persons can never handle ahorse, with all the instruction in the icorld — it is not in them. They cannot establish a sympathy between themselves and the horse, and if they become horse trainers, they have only mistaken their calling, and the money they laid out is perhaps aa cheap a way as they could be taught their mistake.
To be a succesx/id horse trainer, he must have a sympo:' ihi/ with the horse, and a personal power of control. This reminds us of an old gentleman's remarks on the subject of sweeny. He said : " There were a great many recipes of penetrating oils, applications, etc., but the great secret was in faith," without which no person will pensevcro a sufficient length of timo'with either of them. This holds good in all diseases, as well as in handling or taming a horse.
As for recipes, they consist in using the horse-castor or wart, which grows upon the inside of the leg, grated fine, oil of cumin, and oil of rhodium, kept separate in air-tight Dottles ; these all possess peculiar properties for attracting ajd subduing animals.
•' Hub a little oil of cumin upon your hand, and approach the horse in the field, on the windward side, so that he can smell the cumin. The horse will let you come up to hin without trouble.
'*■ Ivrimediately rub your hand gently on the horse's nose^ gettiu,^ a little of the oil on it. You can then lead him any whore. Give him a little of the castor on a piece of loaf-sugar, apple, or potato.
" Put eight drops of the oil of rhodium into a lady't thimble. Take the thimble between the thumb and middle fiugei of your right hand, with the fore-finger stopping the mouth of the thimble to prevent the oil from running out whilst you are opening the mouth of thp horse.
" As soou as you have opened the horse's mouth, tip th< thimble over upon his tongue, and he is your servant. He will follow you like a pet dog. Very doubtful. — Author.
" If you want to teach him to lie down, stand on his nigh or left side ; have a couple of leather straps, about six feet long ; string up his left leg with one of them around his neck ; strap the other end of it over his shoulders ; hold it in your hand, and wLea you are ready, tell him to lie down, at the same time gently, Crmly, and steadily puMing on the strap, touching him lightly with a switch. The horse will immediately lie down. Do this a few times, and you can make him lie down without the straps.
" He is now your pupil and friend. You can teach him anything, only be kind to him — be gentle. Love him and he will luvo you. Feed him before you do yourself. Sheltei him well, groom him yuurseli', keep him clean, and at night always give him a good bed."
It will be perceived, by reference to vho following item IVom Bell's Li/e, that the secret for taming horses, by which Mr. llarey has made himself so rich and famous, instead of being a divination of his own, was probably obtained by him through some accidental contact with an old rohune, which had long disappeared from observation, and hardly held a place in public libraries :
A correspondent sends us the following : " In the Gentleman's Farriery, by Bartlett. (sixth edition) publish«d in 1702, (one hundred years ago,) page 293, is the followJog: ' The method proposed by Dr. lirackcn ifl to tie up on« oi
CABINET MAKERS DEPARTMENT. 260
tlif. fore feet close, and to fasten a cord or small rope about the other fetlock, bringing the end ot it over the horse's shouldci8 ; then }et him be hit or kicked with your foot behind that knee, at the i^aiue time pulling his nose down strongly to the manger You will bring him upon his knees, where ho should be held till he is tired which cannot be long, but if he does not lie down soon, let hnn be thrust sidewaj's against his quarters, to throw him over; by forcing him down several times in this way, you may teach him to lie down, at the same words you first used for that purpose " You will see that Mr. Kiirey '8 system is exactly the same.
From the foregoing it will be seen that he obtained the knowledge, and naturally possessing the fivvaucs^, fearless energy, and muscle sufficient to back the whole, he has become the horse tamer of the world.
POLISH— Fou New FuRKiTUKE.— Alcohol 98 per cent. 1 pt. ; gums copal and shellac, of each 1 oz. ; dragon's blood J^ oz. Mix and dissolve by setting in a wann place.
Although this professes to be for new work, it does not hurt the looks of old, not the least bit ; try it all who want their furniture to show a gloss and answer in place of lookingglasses, i
it just the thing desired,
2. Polish fou Reviving Old Furniture, Equal to tpui "Brother Jonathan."— Tiike alcohol 1^ ozs.; spirits of salU (muriatic acid) i oz. ; iinseed-oil 8 ozs.; best vinegar i pt.; and butter of antimony 1^ ozs.; mix, putting in the vinegar last.
It is an excellent reviver, making furniture look nearly equal to new, and really giving a polish to now work, alwaya shaking it as used. But if you cannot get the butter of antimony, the following will be the next best thing :
3. Polish for Rsmoving Btains, Spots, akd Mildew, from Furniture.— Take of 93 per cent, alcohol ^ pt.; pulverized rosin and gum sliellac, of each "J ox. Let these cut in the alcohol; then add linsecd-oil i pt.: shake well, and apply with a eponge, brush, or cotton tiannel, or an old newspaper, rubbing it well after the application, which gives a nice polish.
These are just the thing for new furniture when sold and about to be taken out of the shop ; removing the dust and giving the new appearance again.
4. Jet, or Polish for Wood or Leather, Black, Red, oh Blue. — Alcohol (1)8 per cent.) 1 pt. ; sealing wax, the color desired, 3 sticks ; dissolve by heat, and have it warm when applied, A. sponge is the best to apply it with.
For black on leather it is best to apply copperas watei first, to save extra coats; and paint wood the color desired also, for the same reason. On smooth surfaces, use the tallow and rotten stone as in the first polish. It may be applied to carriage-bodies, cartridge-boxes, dashes, fancy-baskets, straw-bonnets, straw-hats, &c.
FURNITURE — Finishing with only One Coat of Varniph. WOT Using Glue, Paste, or Shellac. — Take boiled linseed-oil and give the furniture a coat with a brush ; then immediately sprinkle dry whiting upon it and rub it in well with your hand., yr a brush which is worn rather short and stitF, over all the surface— the whiting absorbs the oil ; and the pores of the wood are thus filled with a perfect coat of putty, which will last lot ages ; and water will not spot it nor have any effect upon it.
For mouldings and deep creases in turned work, you can mix them quite thick, and apply them together, with the old brush, but on smooth surfaces, the hand and dry whiting are best. If black walnut is the wood to be finished, you will put a trifle of burned umber in the whiting, — if for cherry, a little Venetian-red ; beech or maple nrJl re*
quire less red. Only sufficient is to be used, in either case, to make tlie wliiting the color of the •wood, being finished. Bedstead-posts, banisters, or standards for bedsteads and all other turned articles can have the finish put on in the lathe, ia double quick time ; spreading a newspaper on the lathe to save the scattering whiting, applying it with the hand or hands, having an old cloth to rub off the loose whiting which does not enter the pores of the wood, — the same with Bmooth surfaces also.
This preparation is cheap ; and it is a wonder that furniture men have not thought of it before. Three coats of varnish without it is not as level as one with it. From the fact that some of the varnish enters the pores of the wood and does not dry smooth; but with the pores filled with this preparation, of course, it must dry smooth and level, without rubbing down.
STAINS — MAnoGANY on Walkut, Natural as Natuke. — Apply aquafortis by means af a rag tacked to a slick ; for if you use a brush it Avill very soon destroy it. Set the furniture in the hot sun to heat in the aquafortis, if no sun, heat it in by a stove or fire.
ing. Finish up in every other way as usual.
This finish is applicable to fancy tables, stands, lounges, coffinSj &c., and equally beautiful on knots and crotches, giving walnut the actual appearance of mahogany, and as it is appearances only that most people depend upon, why will not this do as well as to trasport timber from beyond the seas.
2. RosE-wooD Stain, Veky Bright Shade — Used Cold.— Take alcohol 1 gal.; camwood 3 ozs.; let them stand in a warm place 24 hours ; then add extract of logwood 8 ozs.; aquafortis 1 oz.; and when dissolved it is ready for use ; it makes a very bright grnuud, like the most beautiful rose-wood — one, two or mora coats, as you desire, over the whole surface.
ones is made by applying, in waves, the following :
Take iron turnings or chippings, and put vinegar upon them; (et it stand a few hours and it is ready to apply over the otlicr, by means of a comb made for graining ; or a comb made from thinnish India-rubber ; the teeth should be ratlier good length ; eay half an inch, and cut close together or further apart, as desired ; and with a little practice, oxcelleat imitation will be mad*.
This, for chairs, looks very beautiful to apply me darken ing mixture by means of a flat, thin-haired, brasn, leaving only a little ol" the red color in eight ; and if you want t« make the cringles, as sometimes seen in rose-wood, it is done with a single tooth or pen, bearing on sometimes har4 ?ifld then light, &o., &c. All can and must be got by prae tic«.
a lower shade, use the next recipe.
8. Rose- WOOD Stain— Lianx Shade— Take equal parts of logwood and redw'>ud chips, and boil well in just suftlcicnt water lo make a strong stain; apply it to the furniture while hot, 1 ot 2, or even 3 coats may be put on, one directly after the other, according to the depth of color desired.
4. Rose- Pink, Stai»{ and Varnish, Also Used to Imitatb RosE-wooD. — Put an ounce of potash into a quart of water, with red Banders H ozs.; extract the color from the wood end strain; then add gum shellac i lbs.; dissolve it by a quick fire — used upon logwood Etain for rose-wood imitAiion.
5. Black Walnut Stain. — Whenever persons are using walnut which has sap-edges, or if two pieces are being glued together which are different in shade, or when a poplar pannel, or other wood is desired to be used to imitate black walnut, you will find the following to give excellent sati* faction :
can while hot
When desired to use any of it, pour out and reduce with turpentine to the right shade for the work being stained. With a little practice you can make any shade desired. If used with a brush over a red stain, as mentioned in tke rose* wood stain recipes, especially for chairs and bedsteads, it very nearly resembles that wood. Mixing a little varnish with the turpentine when reducing it, prevent* it from spotting, and causes it to dry quicker. By rubbing a little lamp-black with it you oan make it a perfect black, if desired.
6. CnERKT Stain. — Take rain water 3 qts.; anotta 4 ozs.; boil vn a copper kettle until the anotta is dissolved ; then put in a piece of potash the size of a common walnut, and keep it on the fire about half an hour longer, and it is ready lor use. Bottle for keeping.
Tliis makes poplar or other light-colored woods so near the color of cherry that it is hard to distinguish ; and even improves the appearance of light-colored cherry.
over a stove fire.
It is applied to iron, frames of door plates, back-grounds m crystal painting, etching upon glass, and also for fencewire, or screens which are to go into water above mills to turn leaves and drift-wood, &c.
2. Patent Varnish, for Wood or Canva.«ss.— Take spirits of turpentine 1 gal.; asphaltum 2^ lbs.; put them mto an iron kettle which will fit upon a stove, and dissolve the gum by heat. VVhen dissolved and a little cool, add copal vamish 1 pt., and boiled linseed-oil i pt.; when cold it is ready for use. Perhaps a little lamp-black would make it a more perfect blacK.
or your clothes.
This is valuable for wood, iron, or leather; but for cloth, first make a sizing by boiling flax-seed one quart, in water one gallon ; applying of this for the first coat ; the second coat of comjpon thick black paint ; and lastly a coat of the varnish. Some think that sperm oil, the same quantity, makes a little better gloss.
8. Varnish, Transparent, for Wood. — Best alcohol 1 gnl.; nice gum shellac 2^ lbs. Place the jug or bottle in a situation to keep it just a little warm, and it will dissolve quicker than if hot, or left cold.
This varnish is valuable for plows, or any other article whert you wish to show the grain of the wood, and for pine, when you wish to finish up rooms with white, as the '' Porcelain Finish ;" a coat or two of it effectually prevents the pitch irom oozing out, which would stain the finish.
If this stands in an open dish, it will become thick by evaporation j in such cases add a little more alcohol, and it is a.s good as before. Some do use as much as three and a ._^^-nH. chase's recipes.
half pounds of shellac, but it is too thick to spread well , better apply two or more coats, if necessary. When a black varnish is wanted, you can rub laiup-black with this, for that purpose, if- preferred before the asphaltum, Isu^ given.
then add the water.
No. 2. Take for No. 2, crj'stalized nitrate of silver 1 oz.: ammonia, strongest kind, 3 ozs. ; gum arabic i oz. ; soft water 6 ozs. Observe, in making it, that the silver is to be put into the ammonia, and not corked until it is dissolved ; the gum is to be disEolved in the water, then all mi.xed, and it is ready for use.
Barbers will probably make this amount at a time, as it comes much cheaper than in small quantities ; but if families or others, for individual use, only wish a little, take drachms, instead of ounces, which you see will make only one-eighth of the amount.
Directions for Applying. — First, wash the whiskers or hair with the " shampoo," and rinse out well, rubbing with a towel until nearly dry ; then with a brush ajtply No. 1, wetting completely, and use the dry towel again to remove all superfluous water; then with anflther brush, (tooth-brushes are best,) wet every part with No. 2, and it becomes instantaneously black ; as soon as it becomes diy, wash off with hard water, then with soap and water; apply a little oil, and all is complete.
The advantages of this dye are, that if you get any stain upon the skin, wipe it off with a cloth at the time, and tho washing removes all appearances of stain ; and the whiskers or hair never turn red, do not crock, and ajre a bcauti ful black.
However, cyanuret of potas.sium 1 dr., to 1 oz. of watci. m\\ take off any stain upon the skin, arising from nitrate of silver; but it is poison, and should not tDueh .sore, places nor be left where children may get at it.
r eisuns whose liair 's prematurely gray, -will find dye less trouble in using, tV.an the restoratives ; for when once applied, nothing more needs being done for several weeks ; vhilst the restorati'p'^s are only slow dyes, and yet need Beveral applications. But that all may have the chance of choosing for themsC'es, I give you some of the best restoratives in use.
HAIR RESTORA TIVES AND INVIGORATORS.— Equal TO Wood's, Fon > T riflnig Cost. — Su^ar of lead, borax, and lac-sulphur, of efcb 1 oz.; aqua ammonia i oz.; alcohol 1 gill. These articles to scand mixed for 14 hours ; then add bay rum 1 gill ; hue table salt 1 table-spoon ; soft water 3 pts.; essence of burgamot 1 oz.
^J'his preparation not only gives a beautiful gloss, but will cause hair i< grow upon bald heads arising from all common causes ; and turn gray hair to a dark color.
Mannfr of Application. — When the hair is thin or bald, viPke two applications daily, until this amount is used up, unless the hair has come out sufficiently to satisfy you before that time ; work it to the roots of the hair with a soft brush or the ends of the fingers, rubbing well each tiiue. For gi'ay hair one application daily is sufficient. It is harmless and will do all that is claimed for it, does not ooat only a trifle in comparison to the advertised restoratives of the day; aud will be found as good or better than mosL of them.
2 Invigorator. — Vinegar of cantharides 1 oz.; cologne-Avater 1 o>. ; and rose-water 1 oz. ; mixed and rubbed to the roots of the nair, until the scalp smarts, twice daily, has been very highly recommended for bald heads, ©r where the hair is falling out.
after No. a.
3. Another. — Lac-sulphur and sugar of lead, of each 1 dr. ; tannin and pulverized copperas, each 32 grs. ; rose-water 4 ozs. ; wetting the liaii once a day for 10 or 12 days, then once or twic« a week will keep up the color.
If it is only desired to change gray hair to a dark color the la.5t will do it ; but where the hair is falling out or has already fallen, the first is required to stimulate the scalp to healthy action.
a nice dark color.
I obtained this of one of the Friends, at Richmond, Ind., and for turning white or gray hair, it is a good one. Th« litharge sets the color, as the sulphate of iron does in tK« next. There is but little choice between them.
5. Another. — Rain water 6 ozs. ; lac-sulphur ^ oz. ; sugar o^ lead i oz. ; sulphate of iron (copijcras,) i oz ; flavor with bergwnr.ot essence, if desired ; and apply to the hair daily until si3aciently dark to please.
All the foregoing restorativea will change, or color tL« gray or white hair black, or nearly so ; but let who will tell you that his restorative will give your hair its original color^ just let that man go for all he is worth at the time; for as time advances his worth will be beautifully less.
6. Hair Invigorator. — A Wheeling barber makes xxse of the following invigorator to stop hair from falling out, oi to cause it to grow in ; it is a good one, so i^ the one following it :
Take bay rum 1 pt. ; alcohol i pt. ; castor oil ^ oz. ; carbonate of ammonia i oz. ; tincture of cantharides | oz. Mix, and shako when used. Use it daily, until the end is attained.
8. StiiONG sage tea, as a daily wash is represented to stop hair from falling out ; and what will stop it from falling, is an invigorator and consequently good.
There is not a liniment mentioned in this book, but which, if well rubbed upon the scalp daily for two or three months, will bring out a good head of hair ; when the scalp ha.s become glossy and shining, however, and no fine hair growing, you may know that the hair follicle or root, is dead ; and nothing can give a head of hair in such eases, any more than grain can grow from ground which has had none scattered upon it. This condition may be known by the shining or glistCDing appearance of the scalp
All heads aa well as bodies should be often washed witli soap and clean water ; but if that is neglected too long, it becomes necessary to use somethiug stronger to remove the grease and dandruff — then the following will be found just the thing to be desired.
SHAMPOOING MIXTURES— For Five Cents pek Quakt. —Purified carbonate of potash, commonly called, salts of tartar 1 oz. ; rain water 1 qt. ; mix, aud it is ready for use.
Apply a few spoons of it to the head, rubbing and working it thoroughly ; then rinse out with clean soft water, and dry the hair well with a coarse, dry towel, applying a little oil or pomatum to supply the natural oil which has been Baponified and washed out by the operation of the mixture. A barber will make at least five dollars out of *tiis five cents (vorth of material.
2. Another excellent shampoo is made by using aqua ammonia 3 ozs. ; salts of tartar J oz. ; alcohol ^ oz. ; and soil water 2^ pts. and flavoring with bergamot. In applying, rub the head until the lather goes down ; then wash out.
nut wish to throw any other.
RENOVATING MIXTURES— For Grease Spots, SavMrooiNG, AND KiiiLiNG Bed-Bugs. — Aqua ammonia 2 ozs. ; soft water 1 qt. ; saltpetre 1 t«a-spoon ; variegated shaving soap 1 oz., or one 3 cent cake, finely shaved or scraped; mix all, shake well, and it will be a little better to stand a few hours or days before using, which gives the soap a chance to dissolve.
Directions. — Pour upon the place a sufilcient amount to well cover an^^ grease or oil which may get spilled or daubed upon coats, pants, carpets, &c., sponging and rubbing well and applying again if necessary to saponify the grease in the garment ; then wash off with clear cold water.
Don't squirm now, for these are not half it will dosome people fly entirely off the handle when a preparation is said to do many things — for my part, however, I alwaya admire an article in proportion to the labor which can be performed by it or with it. This preparation will shampoo like a charm j raising the lather in proportion to the amount of grease and dandruff in the hair. It will remove paint, even from a board, I care not how long it has been applied, if oi} was used in the paint — and yet it does not injure the
finest textures, for the simple reason that its affinity is foi grease or oil, changing them to soap, and thus loosening any substance with which they may be combined.
If it is put upon a bed-bug he will never step afterwards * and if put into their crevices, it destroys their eggn and thus drives them from the premises.
Lay the garment on a bench and scour every part thoroughly by dipping a stiflf brush into the mixture j spots of grease and the collar must be done more thorough, and longer continued than other parts, and rinse the garment in the mixture by raising up and down a few times, then the same way in a tub of soft cold water; press out the watei and hang up to dry; after which it needs brushing the waj of the nap and pressing well under a damp cloth.
Beef's gall will set the color on silks, woolen, or cotton — one spoon to a gallon of water is sufficient for this purpose. Spotted bombazine or bombazette washed in this will also look nearly equal to new.
3. Faded and Worn GAR>rENTS — To Eenew the Colok. — To alcohol 1 qt., add extract of logwood i lb. ; loaf sugar 2 oz, ; blue vitriol i oz. ; heat gently until all are dissolved; bottle foi use.
Directions. — To one pint of boiling water put three or four tea-spoons of the mixture, and apply it to the garment with a clean brush; wetting the fabric thoroughly; let dry; :hen suds out well and dry again to prevent crocking ; brush with the nap to give the polish. This may be applied to silks and woolen goods having colors ; but is most applicable to gentlemen's apparel.
COLOGNES — Imperial. — Take oils of bergamot 1 oz. ; reroll 1 dr. ; jessamine i oz. ; garden lavender 1 dr. ; cinnamon 6 drops ; tincture of benzoin 1^ ozs. ; tincture of musk i oz. ; do odorized or cologne alcohol 3 qts. ; rose water 1 pt. Mix.
Allow the preparation to stand several days, shaking occasionally, before filtering for use or bottling. This is rataoi expensive, yet a very nice article. See "llose- Water." ■ 2. CoLOQNB FOB Family Usk — Cheapkb.— Oils of rosemary
and lemon, each i oz. ; bergamot and lavender, each 1 dr. ; cinnamon 8 drops ; clove and rose, each 15 drops ; common alcohol 2 qts. Mix, and shake 2 or 3 times daily for a week.
Colognes need only be used in very small quantities; the game is true of highly flavored oils or pomades ; as too much, even of a good thing, soon disgusts those whom they were intended to please.
HAIR OILS — New York Bauuers', Star. — Castor oil Q} pts ; eilcohol IJ pts.; oil of citronella ^ oz.; lavender J oz.; mixed an(i shaken when used, makes one of the finest oils for the hair it use.
I have been told that this amount of alcohol does not cut the oil. Of course, we know that ; that is, it does not become clear, neither do we want it to do so ; it combines with the oil, and destroys all the gumminess and flavor peculiar to castor oil, by which it becomes one of the best oils for the hair which can be applied. Gills, spoons, or any other measure will do as w^ell, keeping the proportion of flavoring oils ; and if the citronella cannot be got, use some other oil in its place ; none are equal to it, however.
3. Macassar, ou Rose. — Olive oil 1 qt.; alcohol 2| ozs.; rose oil i dr.; tie chipped-alkanet root 1 oz., into 2 or 3 little muslin bags ; let them lie in the oil until a beautiful red is manrfeslod ; rhen hang them up to drain, for if you press them you get out a sediment you do not wish in the oil.
3. Fragrant, HojrE-MADE. — Collect a quantity of the leaves of any of the flowers that have an agreeable fragrance ; or fragrant leaves, as the rose-gferanium, &c. ; card thin layers of cotton, and dip into the finest sweet oil; spnnkle a small quantity of salt ou the flowers; a layer of cotton and then a layer of flowers, until an earthen-ware vessel, or a wide-mouthed glass bottle is full.
Tie, over it, a piece of a bladder ; then place the vessel in the heat of the sun ; and in fifteen days a fragrant oil may be squeezed out, resembling the leaf used. Or, an extract is made by putting alcohol upon the flowers or leaves, in about the same length of time. These are very suitable for the hair, but the oil is undoubtedly the best.
pomades, both in color and action, is made as follows :
Take beef's marrow 1 lb.; alkanet root, not chipped, 1 oz.; put them into a suitable vessel and stew tlieni as you would rciKler tiJlow ; strain through two or three thicknesses of nmsliu, and
laen aao, oi casior on t 'O-; ut^y rnai » g-" ; Oicn la&ee aTraj the peculiar freshness of the marrow ; then use the extract m the common rose- geranium to give it the flavor desired.
taiaed.
BALM OF A THOUSAND FLOWERS.— As strange as it may seem, some of the most astonishingly named ani'jles, are the most simple in their composition. Although thousands of dollars have been made out of the above named article, it is both cheap and simple :
Deoderized alcohol 1 pt.; nice white-bar soap 4 ozs.; shave the soap when put in ; stand in a warm place until dissolved ; then add oil of citroneUa 1 dr.; and oils of neroli and rosemary, of each i dr.
It is recommended as a general perfume ; but it is mora particularly valuable to put a little of it into warm water, with which to cleanse the teeth.
RAZOR STROP-PASTE.— Take the tery finest superfine flour of emery and moisten it with sweet oil ; or you may moisten the surface of the strop with the oil, then dust the flour of emery upon it, which is perhaps the best way.
Nothing else is needed. You must not take any of the coarse flours, nothing but the finest will do. It is often mixed with a little oil and much other stuft" which is of no use, and put up in little boxes and sold at two shillings, not Having more than three cent's worth of emery.
Remarks. — It may not be considered out of place ta make a few remarks here, on the art, as also on the principles, of cookery. For nearly all will acknowledge cooking not only to be an art, but a science, as well. To know how to cook economically is an art. Making money is an art, Now is there not more money made and lost in the kitcken than almost any where else ? Does not many a hard-working man have his substance wasted in the kitchen ? Doc*
not many a shiftless man have his substance saved in the kitchen ? A careless" cook can waste as much as a man can earn, which miglit as well be saved. It is not what we earn, as much as what we save, that makes us well-otf. A long and happy life is tlie reward of obedience to nature's laws ; and to beindependent of want, is not to want what we do not need. Prodigality and idleness constitute a crime against humanity. But frugality and industry, combined with moral vii'tue and intelligence, will insure individual happiness and national prosperity. Economy is an institute of nature and enforced by Bible' precept: '-Gather up the fragments, thai nothing be lost." Saving is a more difficult art than earning : some people put dimes into pies and puddings, where others only put in cents ; the cent dishes are the most healthy.
Almost any woman can cook well, if she have plenty with which to do it ; but the leal science of cooking is to be able to cook a good meal, or dish, with but little out of which to make it. This is what our few recipes shall ass'.st you iu doing
As to the principles of cooking, remember that water can, not be made more than boiling hot — no matter how much you hasten the fire, you cannot hasten the cooking, of meat potatoes, &c., one moment : a brisk boil is sufficient. When meat is to be boiled for eating, put it into boiling water at the beginning, by which its iuices are preserved But if you wish to extract these juices for soup or broth, put the meatin small pieces, into cold water, and let it simmer slowly
The same principle holds good m baking, also. Make the oven the right heat, and give it time to bake through, is the, true plan ; if you attempt to hurry it, you only burn, instead of cooking it done.
CAKES — Federal Cake.— Flour 2^ ^^^-'^ pulverized while sugar 1'^ lbs. : fresh butter 10 ozs ; 5 eggs well beaten ; carbonate ot ammonia Jg oz. ; water J^ pt., or milk is best, if you have It,
Grind down the ammonia, and rub it with the sugar. Rub the butter into the flour; noAv make a bowJ of the iknir, (unless you choose to work it up in a dish,) and put
in the iggA milk, sugar, &c., and mix well, and roll out to about a quarter of an inch in thickness ; then cut out with a round cutter, and place on tins so they touch each other and instead of rising up thicker, in baking, they fill up tne space between, and make a square-looking cake, all attached together. While they are yet warm, drench over with white coarsely-pulverized sugar. If they are to be kept m a show-case, by bakers, you can have a board as large as the tin on which you bake them, and lay a dozen or more tin«ful on top of each other, as you sprinkle on the sugar. 1 cannot see why they are called " Federal," for really, thej are good enough for any " Whig."
Ammonia should be kept in a wide-mouthed bottle, tight ly corked, as it is a very volatile salt. It is known by v^i rious names, as *' volatile salts," " sal volatile," " hartshorn/ *' hartshorn-shavings," &c., &c. It is used for smelling-bot ties, fainting, as also in baking.
2. Rouon-AND-READY Cake. — Butter or lard 1 lb.; molasses ■• qt.; soda 1 oz.; milk or water i pt.; ground ginger 1 tablespoon ; and a little oil ol lemon ; flour sufiicient.
Mix up the ginger in flour, and rub the butter or lard in also J dissolve the soda in the milk or water; put in the molasses, and use ;he flour in which the ginger and butter is rubbed up, and suSicient more to make the dough of a proper consistence to roll out ; cut the cakes out with a long and narrow cutter, and wet the top with a little mola.sses and water, to remove the flour from the cake ; turn the top down, into pulverized white sugar, and place in an oven sufficiently hot for bread, but keep them in only to bake, not to dry tip. This, and the " Federal," are great favorites in Pennsylvania, where they know what is good, and have the means to make it ; yet they are not expoasive.
Dissolve the saleratus in the milk ; beat the eggs separately ; sift the flour and sugar ; first put the sugar intc the milk and eggs, then the flour, and stir all well together, using any flavoring extract which you prefer, 1 tea-spoon — lemon, however, is the most common As soon as the flou)
U .itirred in, put it immediately into a quick oven ; and if it iS all put into a common square bread-pan, for wliich it makes the right amount, it will require about twenty to thirty minutes to bake ; if baked in small cakes, proportion ately less. '
Thoroughly beat the sugar and eggs together ; mix the cream of tartar and soda in the milk, stirring in the flavor also ', then mix in the flour, remembering that all cakes ought to be baked soon after making. This is a very nice cake, notwithstanding what is said of " Berwick," below.
5. BiiRwiCK Sponge Cake w'lTnoDT Milk. — Six eggs, powdered white sugar 3 cups ; sifted flour 4 even cups; cream of tartar 3 tea-spoons; cold water 1 cup; soda.l teaspoon; one lemon.
First, beat the eggs two minutes, and put in the sugar and beat five minutes more ; then stir in the cream of tarcar and two cups of the flour, and beat one minute; now dissolve the soda in the water and stir in, having grated the rind of the lemon, squeeze in half of the juice only; and hiially add the other two cups of flour and beat all one minute, and put into deep pans in a moderate oven. There is considerable beating about this cake, but if ifsel/ does not boat all the sponge cakes you ever beat, we will acknowl edge it to be the heating cake, all around.
see its bulk and beauty.
7. SuGAK Cake. — Take 7 eggs and beat the whites and yolka separately ; then beat well together ; now put into them sifted wliite sugar 1 lb.; with melted butter | lb., and a small teaspoon of pulverized carbonate of ammonia.
' 8. GiJfflEK Cake. — Molassea 2 cups; butter, or one-half lard If you clioose, IJ^ cups; sour milk 2 cups; ground ginger 1 tea-spoon, saleratus 1 heaping tea-spoon.
Mash the saleratus, then mix all these ingredients together in a suitable pan, and stir in flour as long as you can with a spoon ; then take the hand and work in more, just so you can roll them by using flour dusting pretty freely ; roll out thin, cut and lay upon your buttered or floured tins ; then mix one spoon ot molasses and two of water, and with a small brusli or bit of cloth wet over the top of the cakes; this removes the dry flour, causes the cakes to take a nice brown and keep them moist ; put into a quick oven, and ten minutes will bake them if the oven is sufficient!}'' hot. Do not dry them all up, but take out as soon as nicely browned.
We have sold cakes out of the grocery for years, bat nevei ouod any to give as good satistaction as those, eithei at table loi counter. They keep moist, and are sufficiently rich and igbt for ail cake eateis.
9 Tea or Cup Cake— Pour eggs; nice brown sugar 2 cups ; saleratus 1 tea-spoon ; sour imlk 3 cups ; melted butter or half lard 1 cup ; half a grated nutmeg ; flour.
Put the eggs and sugar into a suitable pan and beat together • dissolve the saleratus m the milk and add to the eggs and sugar • put in the butter and nutmeg also stir ad well: then sifl in flour sufficient to make the mass to such a consistence that it will not run from a spoon when ifted upon it. Any one preferring lemon can use that jn place of nutmeg. Bake rather slowly.
cake is made as follows, and it will keep well also:
Flour S^4 lbs. ; sii^ar 13^ lb ; butter 1 lb r water U pt." having 1 tea spoon of saleratus di.ssolved in it. Roil ihiL and bake on tin sheets.
11. Pork Cake, without Butter, Milk, ou Eggs — Al most deligiitful cake is made by the use of pork, which save« the expense of butter, eggs, and milk. It must be tasted to appreciated ; and another advantage of it is that a ou cabf make enough, some leisure day, to last the season >lirouffhB for I have eaten it two montks after it was baked, sitiil nice, and moist. '
BAKER3 AND OOOKIXG DEPARTMENT 285
Fat, salt pork, entirely free of lean or rind, chopped so fine aa to be almoat like lard 1 lb. ; pour boiling water upon it i pt. ; raisins seeded and choppod 1 lb. ; citron shaved into shreds i lb. ; sugar 2 cups ; molasses 1 cup ; saleratus 1 tea-spoon, rubbed fine and put into the molasses. Mix these all together, and stir in sifted flour to make the consistence of common cake mixtures ; then stir in nutmeg and cloves finely ground 1 oz. each ; cinnamon, also fine, 2 ozs. ; be governed about the time of baldng it by putting a sliver into it — when nothing adheres it is done. It should be baked slowly.
You can substitute other fruit in place of the raisins, if • dfisired, using as much or as little as you please, or none at all, and still have a nice cake. In this respect you may call it the accommodation cake, as it accommodates itself to th< wishes or circumstances of its lovers.
Ueat the eggs, sugar, and butter together, and stir in the flour and nutmeg; dissolve the saleratus in the cider and stir into the mass and bake immediately, in a quick oven.
13. Ginger Snaps.— Butter, lard, and brown sugar, of each i lb.; molasses 1 pt. ; ginger 2 table-spoon ; flour 1 qt. ; saleratus 2 tea-spoons ; sour milk 1 cup.
Melt the butter ard lard, and whip in tho sugar, molasses, and ginger ; dissolve the saleratus in the milk and put in ; then the flour, and if needed, a little more flour, to enable you to roll out very thin ; cut into small cakes and bake in a slow oven until snajipish.
Beat the eggs, sugar, and nutmeg together ; dissolve tho saleratus in the milk, and mix ; then stir in flour to make only a thin batter, like pan-cakes ; three or four spoons of the batter to a common round tin; bake in a quick oven I'hree or four of these thin cakes, with jelly between, form one cake, the jelly being spread on while the cake is warm
15. Roll, Jelly Cake. — Nice brown sugar 1^ cups ; 3 eggs ; sweet skim milk 1 cup; flour 2 cups, or a Utile more only; cream of tartar and soda, of each 1 tea-spoon ; lemon essence 1 teaBpoou.
cream of tartar and soda with the milk, stirring in the flavor also ] now mix in the flour, remembering to bake soon, spreading thin upon a long pan ; and as soon as done spread jelly upon the top and rail up ; slicing off only as used ; the jelly does not come in contact with the fingers, as in the last, or flat cakes.
-Molasses li cups; saleratus 1 tea ; 3 eggs ; butter, lard, or pork gravy, on a spoon ; if you use lai'd add, a littlb
Mii all by beating a minute or two with a spoon, dissuhring the saleratus in tlie milk ; then stir in flour to give the consistence of soi't-cake, and put directly into a hot o<en, being careful not to dry them up by over-baking, as it iS a soft, moist cake, that we are after.
32. Marbled Cake. — Those having any curiosity tc gratify upon their own part, or on the part of friends, will be highly pleased with the contrast seen when they take a piece of a cake made in two parts, dark and light, as follows :
Lion-r Part. — 'Wliite sugar li^ cups ; butter i cup ; sweet milk i Csip; soda i tea-spoon; creum of tartar 1 tea-spoon ; whites ol i eggs ; tlour 2^ cups ; beat and mixed as " Gold Cake.'I
Dark Paut. — Brown sugar 1 cup ; molasses i cup ; butter ^ c up , sour milk ^ cup ; soda l tea-spoon ; cream of tartar 1 tcas^poou ; tlour 2i cups ; yolks of 4 eggs ; cloves, allspice, cinnamon, and uatmeg, ground, of each i table-spoon ; beat and mixed as " Gold Cake."
Directions. — When each part is ready, drop a spoon of dark, then a spoon of light, over the bottom of the dish, in which it is to be baked, and so proceed to fill up the pan dropping the light upon the dark as you continue with the dilierent layers.
33. SiLVKK Cake. — AVhitcs of 1 doz. egg* ; fiour 5 cups; white sugar and butter, of each 1 cup ; cream or s\\ eet mi!k 1 cup; cream of tartar 1 tea-spoon; soda i tea-spoon; beat and mix as the " Gold Cake." Bake in a deep pan
34. Gold Cakk. — Yolka of \ doz. eggs ; flour 5 cups ; white sugar 8 cup* ; butter 1 cup ; cream or sweet milk 1^ cups ; soda ^ tea-spoon • cream of tartar 1 tea-spoon. Bake in a deep loaf pan.
IJeat th» eggs with the sugar, having the butter softened by the fire ; then stir it in ; put the soda and cream of tartar into the cream or milk, stirring up and mixing all together ; then sift and stir in the tieur.
35. EaiDE Cake. — Presuming that this work may fall into the hands of some persons who may occasionally have a wedding amongst them, it would be imperfect without a " wedding cake," and as I have lately had an opportunity to test this one, upon "such an oecasion," in my own family, I can bear testimony, so can tht ''printer," to its adaptsuon for ail similar displays.
Take butter 1^ lbs. ; sugar If lbs., half of whicli is to be CH^ leans sugar ; eggs well beaten, 2 lbs. ; raisins 4 lbs. ; having thfl seeds taken out, and chopped ; English currants having the grrt picked out and nicely washed 5 lbs. ; citron, cut fine, 2 lb» filled flour 2 lbs. ; nutmegs 2 in number, and mace as much in bulk ; alcohol 1 gill to i pt., in which a dozen or fifteen drop» cf oil of lemon iSive been put.
When ready to make your cake, weigh your butter and cet it in pieces, and put it where it will soften, but not. welt Next, stir the butter to a cream, and then add the sugar, and work till white. Next beat the yolks of the eggs, and put them to the sugar and butter. Meanwhile another person should beat the whites to a stiff froth and put them in. Theii add the spices and flour, and, last of all, the fruit, except the citron, whiahis to be put in about three layers, the bottom layer about one inch from the bottom, and the top one, an inch from the top, and the other in the middle, smoothing the top of the cake by dipping a spoon or two of water upon it for that purpose.
The pan in which it is baked should be about thirteen inches across the top, and five and a half or six inches deep, without scollops, and two three-quart pans also, which it will fill ; and they will require to be slowly baked about three to four hours. But it is impossibl-j to give definite rules as to the time required in baking cake. Try whether the cake ia done, by piercing it with a broom splinter, and if nothing adheres, it is done.
Butter the cake pans well ; or if the pans are lined with buttered white paper, the cake will be less liable to burn. Moving cakes while baking tends to make them heavy.
The price of a large " Bride Cake," like this, would be about twelve dollars, and the cost of making it would be about three dollars only, with your two small ones, which would cost as much to buy them as it does to make the whole three.
The foregoLag was written and printed over a year ago. The daughter came home, and took dinner with us, one year from the marriage ; and her mother set on some of the cake as nice and moist as when baked.
occasion.
37. FKoe-riNG, on Ictno, fob Cakes. — The whites of 8 egg« beat to a perfect froth aud stiff; pulverized white sugar 2 lbs.; starch 1 table-spoon ; pulverized gum arable i oz. ; the juice oi 1 lemon.
Sift the sugar, starch, and gum arabio into the beaten egg, tnd stir well and long. When the cake is cold lay on a coat of the frosting ; it is best not to take much pains in putting on the first coat, as little bits of the cake will mix up with it, and give the frosting a yellow appearance ; but on th« next day, make more frosting the same as the first, and apply a second coat, and it will be white, clear, and beautiful. And by dipping the knife into cold water as applying, you can smooth the frosting very nicely.
Qour 2 qts.
Rub thoroughly together with the hand, and wet up with cold water; beat well, and beat in flour to make quite brittle and hard ; then pinch off pieces and roil out each cracker by itself, if you wish them to resemble bakers' crackers.
the size of Boston crackers, you will say it is nice indeed.
41. BucKWira> r Suokt-cake. — Take 8 or 4 tea-cups of nice sour milk, 1 tea-epoon of soda-saleratus dissolved in the milk ; if the milk U very sour, you must use saleratus in proportion, witii i» little salt ; mix, up a dough with buckwheat flour, thicker th«u fou would mix the same for griddle-cakes, say quite stitf; put mto a buttered tin, and put directly mto the stove oveu and bake about 30 minutes ; or aa you would a short-cake from common flour.
It takes the place of the griddle-cake, also of the shorv cake, in every sense of the word — nice with meat, butter, honey, molasses, &c No shortening is used, and no need of setting your dish of batter over night, for a dmnkeo
husband to set his foot in. Wet the top a little, and warm it up at next meal, if any is left — it is just as good as whea firet made, while griddle-cakes have to be thrown away. It h also very good, cold.
"Was the beaut}' of this cake known to the majority of persons, throughout the country generally, buckwhea( would bcconjc as staple an article of commerce as the common wheat. Do not fail to give it a trial. Some persons, in trying il, have not had good luck the fii-st time ; they have failed from the milk's being too sour for the amount of saleratus used, or from making the dough too thin. I think I can say we have made it hnmlnJs of times with success, as f could eat it while dyspeptic, when I could eat no other warn) bread.
43. Yeast Cake.— Good lively j-cast 1 pt.; rye or wheat floui to form a tliit-k batter; salt 1 tea-si)Oon ; stir in and set to use when lisen, svir in Indian meal, until it will roll out good.
When again risen, i-oll out very thin; cut them intc cakes and dry in the shade ; if the weather is the leas! damp, by the fire or stove. If dried in the sun, they will "crraent.
To use: Dissolve one in a little warm water, and stir in a couple of table-spoons of flour; set near the fire, and when light, mix into the bread. If made perfectly dry, they will keep for six mouths.
BREADS— Yankee Brown Bkead. — For each good sized loaf being made, tuke H pts. corn meal, and pour boiling water upon it, to scald it properly ; let stand until only blood warm. lUen put about 1 (it. of r3'e flour upon the meal, and pour in a good bowl of emj)tyings, with a little saleratus dissolved in a gill of water, kneading in more flour, to make of the consistence of common bread. If you raise it with yeast, put a little salt ib Die meal, but if you raise it with salt-risings, or emptymgt wliich I prefer, no more salt is needed.
Form into loaves, and let them set an hour and a half, oi Until light ; in a cool place, in summer, and on the hearth, or under' the stove, in winter; then bake about two hoursMake the dough fully as stilf as for wheat bread, or a little harder ; for if made too soft it does not rise good. The old style was to use only one-third rye flour, but it does not wear if made that way ; or, in other words, most persons ge< tired of it when mostly corn meal, but I never do whs rao><tly rye flour.
Let all persons bear iu mind that bread should never bo •dten the day on which it is baked, and poutively must this bfc observed by dyspeptics. Hotels never ought to be without this bread, nor families who care for health.
2 Graham Bread. — I find in Zion's Herald, of Boaton, edited by Rev. E 0. Haven, formerly a Professor in the University at this city, a few remarks upon the " Differ ent Kinds of Bread," including Graham, which so full explain the philosophy, and true principles of breadmaking, that I give them an insertion, for the benefit of bread-makers. It says :
" Rice flour added to wheat flour, enables it to take up an increased quantity of water," [See the " New French Method of Making Bread."] " Boiled and mashed potatoes mixed with the dough, cause the bread to retain moisture, and prevent it from drying and crumbling. Bye makes a dark-colored bread ; but it is capable of being fermented and raised in the same manner as wheat. It retains its freshness and moisture longer than wheat. An admixture of rye flour with that of wheat, decidedly improves the lat ter in this respeet. Indian corn bread is much used in thi. country. Mixed with wheat and rye, a dough is produced capable of fermentation, but pure maize meal cannot be fermented so as to form a light bread. Its gluten lacks the tenacious quality necessary to produce the regular cell-structure. It is most commonly used in the form of cakes, made to a certain degree light by eggs or sour milk, and saleratus, and is generally eaten warm, Indian corn is ground into meal of various degrees of coarseness, but is never made so fine as wheaten flour. Bread or cakes from maize require a considerably longer time to be acted upon by heat in the baking process, than wheat or rye. If ground wheat be unbolted, that is, if its bran be not separated, wheat meal or Graham flour results, from which Graham or dyspepsia bread is produced. It is made in the same general way as other wheaten bread, but requires a little peculiar manage ment. Upon this point, Mr, Graham remarks :
The wheat meal, and especially if it is ground coarsely, swells consioerably in the dough, and therefore the dough should not at first be made quite so stiff as that made of superSse flour ; and when It is raised, if it is foimd too soft to mould well, a litUe
more mtsal may be added It should be remarked that dough made of wheat meal will take on the acctoua fermentation, or become sour sooner than that made of line flour. It rcquircB f hotter oven, and to be baked longer, but must not stand so long after being mixed before baking, as that made from flour.
3. BuowN BitEAD Biscurr. — Take com meal 2 qts.; rye flom 8 pts.; wheat flour 1 pt.; molasses 1 tiible-apoon ; yeast 3 tab!» spooiiS, having so<ia 1 tea-spoon mixed with it.
eaten.
4. Dyspeptics' Biscuit and Coffek. — Take Graham-flour (wheat coarsely ground, without bolting,) 2 qts.; com raeal sifled, 1 qt.; butter i cup; molasses 1 cup; sour milk to wet it up with siUeratus' as for biscuit.
Roll out and cut with a tea-cup and bake as other biscuit , and when cold they are just the thing for dyspeptics. And if the flour was sifted, none would refuse to eat them :
Fob the Coffee. — Continue the baking of the above biscuit in a slow oven for six or seven hours, or until they are browned through like coffee.
4ud sugar as other cofloe.
Dyspeptics should chew very fine, and slowly, not driokiDg until the meal is over ; then sip the coffee at their leisure, not more than one cup, however. This will be found very nice for common use, say with one-eighth coffee added ; hardly any would distinguish the difference between »t and that made from coffee alone. The plan of buying ground ccffee is bad ; much of it is undoubtedly mixed with peas, which you can raise for less than fifteen or twenty o<>uta a pound, and mix for yourself.
:hat it contains sound sense :
" To make a half-peck loaf, take f lb. of well boiled «ealy potatoes, mash them through a fine cullender or coarse neve , add i pt. of yeast, or J oz. of German dried-yeast, and H P* o^ luke-warm water, (88 deg. Fab:.} together with } lb. of floiu, to render the mixture the consistence of thin batter; this mixture is to be set aside to ferment: if set in a warm place it will nae bi le^ than 2 hours, when it resembles yeast, except in ooioc.
Tlje sponge so made is then to be mixed with 1 pt. of water, nearly blood warm— viz. 93 deg. Fahr., and poured into a halt, peck of tlour, which has previously had 1^- ozs. of salt mixed into it ; the whole should tlien be kneaded into dough, and allowed to rise in a warm place fcr 2 hours, when it should be kneaded tuto loaves and baked." *
The object of adding the maslied potatoes is to increa:«e the amount of fermentation in the fipouge, which it does tc a very remarkable degree, and consequently, renders th« bread lighter and better. The potatoes will also keep the bread moist.
(5. Old Baciieloh's Buead, Biscuit, ok Pie-Ckust.— Fioui 1 qt. ; cream of tartar 2 tea-spoons ; soda | tea-spoon ; sweet milk to wet up the flour to the consistence of biscuit dough.
Rub the flour and cream of tartar well together ; dissolve the soda in the milk, wetting up the flour with it and bake immediatdi/. If you have no milk, use water in its place, adding a spoon of lard to obtain the same richness. It does well for pie-crust where you cannot keep up sour milk.
7. New Fiiencii Method of JIaking Bread. — Take rice j lb.; tie it up in a thick linen bag, giving ample room for it to swell ; boil it from 3 to 4 hours, or until it becomes a perfect paste; mix this while warm with 7 lbs. of flour adding the usual quantities of yeast and salt ; allow the dough to work a proper time near the fire, then divide into loaves. Dust them in, and knead vigorously.
This quantity of flour and rice makes about thirteen and one-half lbs. of bread, which will keep moist much longei than without the rice. It was tested at the London Poly technic Institute, after having been made public in France, with the above results.
8. Bakino Powt)er8, for Biscuit Without Shortening. — Bi-c.'u-bonate of soda 4 ozs.; cream of tartar 8 ozs.; and properly dry them, and thoroughly mix. It should be kept in well corked bottles to prevent dampness which neutralizes the acid.
Use about three tea-spoons to each quart of flour being baked ; mix with milk, if you have it, if not, wet up with cold water ajid put directlij into the oven to bake.
add the water, brown sugar, and flour, working the mass into a smooth ]>aste; beat the eggs and mix with the paste, Raving the whites of two of them ; make two pics, baking with no top crust ; wliile these are baking, beat the whites of tlr<! two eggs, saved for that purpose, to a stiff froth and stir iu the wliite sugar; when the pies are done, spread this frosting evenly over them, and set again in tlx; oven and brown slightly.
2. PiE-CiiLST Glaze. — In making any pie which has a juicy mixture, the juice soaks into tlie crust, making it soggy and unfit to eat j to prevent this :
pie mixture.
For pies which have a top crust also, wet the top with the same bei'ore baking, which gives it a beautiful yellow brown. It gives beauty also to biscuit, ginger cakes, and is iust the thing ibr rusk, by putting iu a little sugar.
3. ArPLE l^iE ■WHICH is Dioestibi.e. — Instead of mix ing up your crust with water and lard, or butter, making it very rich, with shortening, as customary for apple pies :
Jlix it up (vciy way just ns you w ouid for biscuit, using sour milk and salernius, wiih a li'ttk lard or butter only ; mix the dough quite stirt, roll out rathcT Ihiii, lay it upon your tin, oi plate ; aud liaving ripe ajjides sliced or chopped nicely and laid on, rather thick, and sugar according to the acidity of the apples, then a top crust, and bake Avell, putting the I'gg upon tlie crusts, as mentioned in the "Tie Crust Glaze," and you have got a pie that is fit to eat.
But when you make tlie rich crust, and cook the apples and put them on, it soaks the crust, which does not bake, and no stomach can digest it, whilst our way gives you a nice light crust, and does not take half the shortening of the other plan ; yet perhaps nothing is saved pecuniarily, a:; butter goes as finely with the biscuit-cru.st-pies, when hot, as it does with biscuit ; but the pie is digestible, and wher it is cold, does not taste bad to cut it up on your plate, with plenty of sweetened cream.
4. Apple Ccstakd Pie — The Nicest Pie ever Eaten.— Peel so>u- a])i>lcs and 8tew nntil soft and not much water left in them; then rub tliem throiigli a cullender — beat 3 eggs for each pie to be baked ; and put in at the rate of 1 cup of butter and 1 of sugar for y !>>»; sesison with nutmeg
My ■wife has more recently made them with only 1 egg to each pie, vath only half of a cup of butter and sugar each, to 4 or 5 pitw; but the amount of sugar must be governed sometvhat by the cicjdity of tho apples.
Bake as pumpkin pies, which they resemble in appearance; and between them and apple pies in taste j very nice indeed. "We find them equally nice with dried apples by Diakiny: them a little more juicy.
If a frosting was put upon them, as in the "Lemon Pie,** (hen returned, fur a lew moments, to the oven, the appearance, at least, would be improved.
5. Appi.k Custard, Very Nice. — Take tart apples, that are Quite juicy, and stew and rub them, as in the recipe above, ano to 1 pt. of the apple, beat 1 eggs and put in, vviih 1 table-spoon ol sugar, 1 ol butter, and i of a grated nutiiitg.
G. Pastk for Tarts. — Loaf sugar, flour, and butter, equal weights of each; mix thonuighly by beating with a rolling-pin, for half an hour ; folding up ai;d bcatiijg again and again.
"When properly mixed, pinch ofF small pieces and roll out each crust by itself, which causoh them to dish so as to hold the tart-mixture. And if you j/ill have a short pie-crust, this is the plan to make it.
PUDDINGS— Biscuit Puddimo, "Without Re-Baking.— Take water 1 qt. ; sugar i lb. ; butter the size of a hen's egg; Qjur 4 table-spoons; nutmeg, grated i of one.
Mix the flour with just sufficient cold water to rub up ali the lumps while the balance ol the water is heating, mix all, and split the biscuit once or twice, and put into this cravy while it is hot, and keep hot until used at table. It uses up cold biscuit, and I prefer it to riv;her puddings. It 18 indeed worth a trial. This makes a nice dip gravy also for other puddings.
2. Old English Christmas Plum Pudding — Tho llarrisburg Tekf/raph furnishes its readers with a recipe for the real " Old English Christmas Plum Pudding." After having given this pudding a fair test, lam willing to endorse every word of it ; and wish for the holiday to tome oftcnei than once a year :
well stoned bat not choppetl, currants thonjug''..'- w-asbcd, 1 lb. t'iich; chop suet 1 lb. very finely, and mix wilti tn«'m-, add i lb. of flour or bread very finely crumbled ; 3 ozs. of sucar ; 1 i ozs of grated lemoa peel, a blade of mace, | of a small nutmeg, 1 tea spoon of ginger, | doz. of eggs, well beaten; work it well together, put it in a cloth, tie it firmly, allowing room to swell ; put it into boiling water, and boil not less than two hours. Ilohould not be sutfered to stop boiling.
The cloth, when about to be used, should be dipped into oiling water, squeezed dry, and floured ; and whei the pudding is done, have a pan of cold water ready, and dip it in for i. moment, as soon as it comes out of the pot, which prevents the pudding from sticking to the cloth. For a dij)gravy for this or other puddings, see the "Biscuit l*udding, without Re-Baking," or "Spreading Sauce for Puddings."
Scald the milk, and stir in th<i meal whilst boiling; then let it stand until only blood-warpi, and stir all well together, and bake about one and a half hours. Eaien with sweetened cream, or either of the pudding saucer mentioned in tlie " Christmas Pudding."
sins 1 lb.
Scald the meal, having the salt in it ; when cool stir in the beaten eggs ; dissolve the saleratus in the milk and stir in also, then the raisins; English currants, dried, currants, or dried berries, of any kind, answer every purpose, and are, in fact, very nice in place of the raisins. Boil about one and a half hours. Eaten with sweetened cream or any of the pudding sauces. Any pudding to be boiled must not be put into the water until it boils, and taken out a.* soon as 'one, or they become soggy and unfit to eat.
5. Quick Indian Pudding. — Take 1.1 cups o*" sour milk; 2 eggs well beaten ; 1 small tea-spoon of saleratus; dissolved in tiie milk; then sift in dry corn meal, and stir to the consistence of corn bread; then stir in ^ lb. of any of the fruits mentioned above; or, if you have no fruit, it is quite nice without;
Tie up and boil one hour ; sweetened cream with a little nutmeg makes a nice sauce. As I have just eaten of thui for my dinner, I throw it in extra, for it is worthy.
6. Flour Pudding, To Boil. — When persons have plenty of dried apples or peaches, aad not much of the smaller fruits ; or desire to change fn-ui them in puddings :
Take wheat flour sufficient to make a good pan of biscuit, and mix it up as for biscuit, with sour m'lij, saleratus, and a little Outter or lard, roll out rather thicker than for pie-crust; r.ow having your apples or ]ieaciies nicely stewed wet the crust ovci fith the " Pie Crust Glaze," then spread a layer ol the fruit upon i», adding a little sugar, as it lies upon the table; and if you I boose, scatler over them a handful of raisins, or any otlier of tiie dried fruits mentioned ; '•oil up the whole together, and boil 1 hour.
Eaten with any sauec »vhieh you may prefer, but the corn meal puddings ar-? Miuch the most healthy, and I prefer their taste to those made from flour.
7. Potato PuDDiNe. — Rub through a cullender G large or 12 middle sized potatoes ; beat 4 eggs, mix with 1 pt. of good milk ; stir in the iiotatoes, sugar and "seasoning to taste; butter the dis^h ; bake i an hour.
This recipe is simple and economical, as it is made of ivhat is wasted in many families, namely, cold potatoes ; tvhich may be kept two or three days, until a sufficient quantity is collected. To be eaten with butter.
Split the kernels lengthwise of the ear with a sharp knife ; then with a ca.se knife scrape the corn from the cob, which leaves the hulls on the cob ; mix it with the milk and other articles, and bake from two to three hours. To be eaten with butter and sugar.
9. Si'EAMED PcDDiKG. — Two eggs ; sugar 1 cup; sour milk 1 cup; saleratus t^ tea-spoon ; a little salt; dried whortleberries, currants, raisins, or other fruit 1 cup ; flour.
Beat the eggs and stir in the sugar; dissolve the salera tu.s in the milk, and mix in also the fruit and salt ; then thicken with flour, rather thicker than for cake ; put into a iwo-quart pun and set in the steamer, and steam an hour uad a half; and I think it will crack open on the back — if not, try again. It is worth the trotfble, especially if you Sttixe plenty of sweetened cream.
Grate the uutineg, and rub all together; these are aoout the proper proportions, hut more or less can be made, aa desired, and more or le«s nutmeg can also be used; or any other flavoring in their place. This sauce is nice on baked puddings, hot or cold ; and to tell it all, it is not bad or bi'^ad. Sec the " Biscuit Pudding," for dip-sauces.
llemove the corn from the cob, as mentioned in the " Green Corn Pudding." The splitting allows the escape of the pulp, whilst the hull is held by the cob ; season, I'urm into small cakes, and ivy to a nice brown, and you have a veiy nice omelet.
2. APPLES — To Bake— Steasiboat Style— Bettei;. tha]» PuESEHVES. — Take moderately sour apples, when ripe ; and wilh a pocket-kuile cut out the stem, and flower-end also, so aa U) rciuove the skin troni thewe cup-shaped cavities ; wash tbem, aiid place them iu a dripping-pan ; now fill these cavities wilb brown su^ar, and pretty freely between them also, with sugar; then lay on a. lew lumps of butter over the sugar; place them, thus ananged, int« the oven w hen you begin to heat m\) the stove for breakfast or dinner, and keep them in until perl'tcily bilked llirough and soft.
Take them up on plates, while hot, by means of a spoon, and dip the gravy, arising from the apple-juice, sugar and butter, over them. Should any of them be left, aftpr the meal is over, set them by until the next meal, when they may be placed in the stove oven until hot, and th^y will have all the beauty of the first baking. Or perhaps some persons may prefer them fried, as follows :
8. Fkieu Apples — Extra Nice. — Take any nice sou»- cooking apples, and, after wiping them, cut into slices about oneionrth of an inch thick: have a frying-jmn ready, in which there is a small amount oi lard, say | or f of an inch in depth. The lard must be hot before the slices of apples are put in. Let one side of them fry until brown; then turn, and put a small quantity of sugar on the browned side of each slice. By the lime Dip, other side is browned, the sugar will be melted" aiid spread over the whole surface.
3 eggs.
Dissolve the saleratus in the milk ; beat the eggs, and put in ; then the flour to make a soft batter ; chop the ap pics to about the size of small peas, and mix them well ii: the batter. Fry them in lard, as you would dough-nuts Eaten with butter and sugar.
5. Appi,e IMekange. — An Excellent Substitute for Pik oii Pudding. — First, take a deep dish and put a bottom crust into it, as for a pie; have nice sour apples, pared, sliced, and stewed, SAveetcning slightly; place a layer of the stcMcd apple upon the crust, say about half an inch in thickness, then put on a layer of nice bread, spread with butter, p.s for eating, then another layer of the apjile ; now place in the oven and bake as a pudding, or pie; when done, have the whites of eggs beaten and rni.xed with a little loaf or other white sugar, say 2 eggs tor a 2-quart dish; place this upon the merange alid return it to the oven for a few minutes, to brown the egg mixture, or frosting. Serve with sugar dissolved in a little water, adding a little iKiiter, with nutmeg, or lemon, as desired or preferred.
fi Bread, To Fut— Better than Toast.— Take bread that IS dry; the dryer the better, so it. is not mouldy; first dip it ralln-r quickly into cold Avatcr, then into eggs which are well beat, liaving a little salt in them ; then immediately fry for a o)r./rt time in hot lard until the surface is a pretty yellow or light orcwu, according to the heat of the lard.
me a.s well as this. But the following is very nice.
7. Toast— Ger.man Style.— Bakers' bread 1 loaf, cut into slices of half an inch in thickress; milk 1 qt. ; 3 eggs, and a little salt ; beat the eggs and mi.x them with the milk", and flavor as for custard, not cooking it however. Dip the sliced bread into the mixture occasionally until it is all absorbed ; then fry the pieces upon a buttered griddle. Serve, for dinner, with su gar syrup, flavored with lemon.
This is the German style of making toast; but is quite good enough for an American. And I have no doubt that home-made bread will ansAvcr all purposes ; ours does, certainly.
Do not fail to give it a trial.
9. Fkkncii Honey. — White sugar 1 lb.; 6 ofgs, leavinjj out the whites of 2; the juice of 3 or 4 lemons, and l'>e grated riml of 3; and i lb. of butter. Siir over a slow fire until it is tbou tlie consistency of honey.
did, upDn trial
10. Muffins. — To each qt. of sweet milk adc' 2 eg^ w^ll beaten ; a lump of butter half the size of an cp,<;, auo fioiu enough to make a stiff batter. Stir in i pt. of yeas*; let tliein stand until jierfectly light, and then bake on a gnddle, n tin rings, made for that purpose.
These are merely strips of tin, three-quarters of ar inch wide, made into rings from two and a half to three inches in diameter, without bottom — the ring being simuly placed on a griddle, and the batter poured in to fill it.
11. Mock Ovstehs. — Si.\, nice, plump, ears ^f rwcet corn, uncooked; grate from the cob; beat 1 egg, stirnutr ii^to it Hour and milk, of each 1 table-spoon ; season with a 'Tttle salt aiul pepper. Put about a tea-spoon of butter into a sujiuble pan l<ir frying, having mixed in the corn also, drop the mixture into the liot butter, one spoon of it in a place, turning them so as to Iry brown. Serve hot, for breakfast.
giving them a trial.
\2. Frlit Jams, Jv,lmks, a.nd Prkskrvk:* — The difference between comnu"^.! preserves, jellies, and iams, is this : I'rcsen-es are made by taking fruit and sugar, pound for pound, and simply cooKing them together until the fruit is done.
VS. Jellies are made by squeezing and straining out the juice only, of the fruit; then taking a pound of sugar for a pound of juice, and cooking until it jells, which is told by taking out a little upon a cold plate.
14. J.\MS are made by weighing the whole fruit, wa.«hing, slicing, and putting in sufficient water to cook it well, then when cool, rubbing it through a fine sieve, and with tliLs pulp, putting in as inncli sugar as there was of tin
fruH noly, and cookiug it very ciirelully, until tlic weight or' tDe jam is tlie same as the I'ruit and added sugar ; the K'iter, you see, is all gone; and this is easily told by having pr«vioaaiy weighed the kettle in which you are cooking iu The jam, if nicely done, contains more of the friiit flavor than the jell, and is as valuable as the jell to put into water as a drink for invalids ; and better for flavoring syrups foj B«»da-fouutaics, &c. Strawberries, raspberries, blackberrios jxiacr.cs, ana pine-apples, make very nice jams for flavoring syrups. Much of the flavor of the fruit resides in the skin, pits, &c. And jams made in this way, from the blackberry, are good for sore mouth, diarrhea, dysentery, &c.
peel of 2 lemons.
Break the peels, and put in with tliC others for a few days : then remove them, and you will have just what you desire, for a trifling cost, compared with the tt?enty-fivo cent bottles, which are so prominently set out as the nicest tiiins^ in the world.
This rule holds good for all fruit oils ; but for fruits, such as peaches, pine-apples, strawberries, raspberries, blackberries, &c., you will take alcohol and water equal parts, and put upon them suffipient to handsomely cover ; and in a few days you have the flavor and juices of the fruit, upon the principle of making " Bounce," which most men know more or less about. If persons will act for themselves, using common sense, working from known facta iike these, they will not need to run after every new-fangled thing which is seen blazing forth in almost every advertisement of the day.
Vanilla, nutmeg, mace, cinnamon, &c., are made by cutr tii.g up the vanilla bean, or bruising the nutmegs, cinnamon, &c., and putting about two ounces to each pint of pure spirit, or reduced alcohol, frequently shaking for about two weeks, and filtering or pouring off very carefully; if foi sale, however, they must be filtered ; for coloring any of the extracts see the " Essences," and " Syrups." For cakea and pies, however, it is just as well to pulverize nutmegs, mace, cinnamon, &c., and use the powder, for the quantity required is so small tjiat it will never be seen in the cake or pie.
MEDICATED WATERS— Rose Water— Take carbonate of magnesia i oz.; oil of rose 30 drops ; drop the oil upon lue magnesia, and rub it together ; then add, rubbing all the time, of distilled water, if you can get it, 1 qt., if not, take the purest rain or snow water,— a porcelain mortar is best, but a bowl doei very well-, — then filter througli filtering paper.
made the same as above.
4. Campitor Water. — To make camphor water, you must first put on a few drops of alcohol ; say 40 or 50 drops, to camphor gum i oz.; and rub the camphor fine, which eDniblofl you to v»'ork it up with magnesia i oz.; then gradually add water 1 qt., as mentioned in the waters above, and filtered.
WASHING FLUID— SAAaNG Half the Wash Board La BOR. — Sal-soda 1 lb.; stone lime i lb.; water 5 qts.; boil a short time, stirring occasionally ; then let it settle and pour off the clear fluid into a stone jug and cork for use; soak your white clothes over night, in simple water ; wring out, and soap whstbands, collars, and dirty or stained places; have your boiler half filled with water, and when at scalding heat, put in one common tea-cup of the fluid, stir and put in your clothes, and boil for half an hour; then rub lightly through one suds only, rinsing well in the bluing water, as usual, and all is complete.
If you wish to wash on Monday, put warm suds to the clothes whilst breakfast is being got ready ; then wring oul and soap as above, will do just as well aa soaking them ovoi night, and my wife thinks better.
For each additional boiler of clothes add half a cup of the fluid only ; of course boiling in the same water through the whole washing. If more water is needed in the boiler for the last clothes, dip it from the^ sudsing tub. Soak your woolen and calico in the suds from which you have
MISCELLANEOUS DEPjLaTMENT 803
washed the white clothes, whilst hanging them out, dipping in some of the boiling water from the boiler, if necessary ; then wash out the woolen and calico as usual — of course, washing out woolen goods before you do the calico. The fluid brightens instead of fading the colors in calico.
This plan not only saves the two rubbings which women give their clothes before boiling, and more than half of the soap — does not injure the clothes, but saves their wear in two rubbings before boiling; and is a good article for removing grease from floors, doors, and windows, and to remove tar or grease from the hands, &c.
I hope every lady into whose hands this recipe may fall, will give it a trial, as my family have now used it over seven years, not missing only two washings. It does not rot clothes, but makes them wash full or more than one-half eaiiier than the old way. Seven years ought to be considered a sufficient test.
Grermany.
I have found many women using turpentine, alcohol, ammonia, camphor gum, &c., in their washing fluids ; but none of them ought ever to be used for such purposes (one woman lost the use of her arm, for six months, by using a fluid containing turpentine) ; the -turpentine and alcohol especially, tend to open the pores of the skin, and thus make the person more liable to take cold in hanging out the clothes, as also to weaken the arm.
And here let me say, if it is possible to avoid it, never iillow the woman who washes the clothes, and thus becomes warm and sweaty, to hang them out ; and especially ought this to be regarded in the winter or windy weather. Many consumptions are undoubtedly brought on by these frequently repeated colds, in this way. It works upon the principle that two thin shoes make one cold, two colds an attack of bionchitis, two attacks of bronchitis one consumption — the end, a coffin.
bhic and liolUs it evenly in the water, so tlmtsiieckingwIllncTcl lake place. One or two table-spoons of it is sufficient for a tub of water, according to the size of tlic tub.
Chinese-blue, when it can be got, is the best, and onlj costs one shilling an ounce, with throe cents for th« acid, will give better satisfaction than Mty cents worth of the common bluing. This amount has now lasted my famiU over a year
bOAPy — Soft Soap — For Half thk Expense akd Oni FouiiTH THE TuouuLE OF THK Old Way — Take white-bar eos j 4 lbs., cut it tine and dissolve, by he.ating in soft w.iter 4 s^al-.; adding sal-soda 1 lb. When all is dissolved and well mixed \l is done.
This soap can be made thicker.or more thin, by using more or less water, as you may think best after once making it. Even in common soft soap, if this amount of sal-soda is put into that number of gallons, washing will be done much easier, and the soap will more than compensate for the ex pense and trouble of the addition.
2. German Ek-vsive, or Yei.i.ov 8o\p. — Tallow anjH aai-soda, of e!\ch 112 lbs.; rosin 56 lbs.; stone lime 28 lbs.: palm-oil 8 lbs. ; soft water 28 gals. ; or for (tmall qunntities, tallow and salsoda, of each 1 lb. ; rosinTozs. ; stone lime 4 ozs. ; palm-oil 1 oz. ; soil water 1 qt.
Put soda, lime, and water into a kettle and boil, stirring well ; then let it settle and pour off the lye. In anotlier kettle, melt the tallow, rosin and palm-oil ; having it hot, the lye being also boiling hot; mix all together stirring well, and the work is done.
y. Hard Soap, with Lard. — Sal-soda and lard, of each 6 lbs. stone lime 3 lbs. ; soil water 4 gals. ; dissolve tlie lime and soda in the water, by Iwiling, stirring, settling and pouring off; tlien return to the kettle (brass or copper) and add the lard and boil until it becomes soap ; then pour into a dish or moulds, and when cold, cut it into bare and let it dry.
This recipe was obtained by finding an over-coat with it in the pocket, and also a piece of the soap; the man kept it with him, as it irritated his salt-rheum so much less than other soaps. It has proved valuable for washing genejtllyj
and also for shaving purpoBca. It would be hotter than half the toilet soaps sold, if an ounce or two of sassafras oil was stirred into this amount ; or a little of the soap might be put in a separate dish, putting in a little of th« eil, to correspond with the quantity of soap.
4. White Hard Soap, wits Tallow. — Fresh slacked lime, Sil-soda, and tallow, of each 2 lbs. ; dissolre the soda in 1 gal. ooilin^ soft water ; now mix in the lime, stirring occasionally or a lew hours; after which let it settle, pouring off the clear liquor and boiling the tallow therein until it is all dissolved ; cool it in a flat ])0x or pan, and cut into bars, or cakes, as preferred.
It can be flavored with sassafras oil, as the last, by stirring it in when cool ; it can be colored also if desired as mentioned in the " Variegated Toilet Soap."
When any form of soda is used in making soap, it is necessary to use lime to give it causticity ; or, in other words, to make it caustic ; which gives it much greater power upon the grease, by removing the carbonic acid ; hence the benefit of putting lime in the bottom of a leach when making soap from common ashes.
a. Tkansparent Soap. — Take nice yellow bar soap 6 lbs.; cut it thin and put into a brass, tin, or copper kettle, with alcoliol i gal.; heating gradually over a slow fire, stirring until all is dissolved ; then add an oui^ce of sassafras essence, and stir unti'". well mixed ; now pour into pans about 1^ inches deep and when cold, cut into square bars, the length or width of the pan, as desired.
Beat up the rosin, mix all -together, and set aside for five days ; then put the whole into a ten gallon cask of warsi water, and stir twice a day for ten days ; at the expiration i)f which time you will have one hundred pounds of excellent soap. 4
7. Chemical Soft Soap. — J. Hamilton, an English gentleman, and proprietor of the Eagle Hotel, Aurora, Indiana, makes his soap for house use, as follows :
the labor is done.
When the caustic soda cannot be obtained of soap-makers, you will make it by taking ssoda-ash and fresh slacked lime, of each eight pounds ; dissolving them in the water with the sal-soda, and when settled, pouring off the clear liquid as in the " White Hard Soap with Tallow."
Judge Buel, says :
" My wife has no trouble about soap. The grease is put into a cask, and strong lye added. During the year, as the fat increases, more lye is stirred in ; and occasionally stirred with a stick that is kept in it. By the time the cask is full, the soap is made for use."
There is no mistake about this manner of making soap. The only object of boiling is to increase the strength of weah lye and hasten the process.
9. Windsor, oe Toilet Soap. — Cut some new, white bar soap into thin slices, melt it over a slow fire, and scent it with oil of caraway ; when perfectly dissolved, pour it into a mould and et it remain a week, then cut it into such sized squares as you
10. Variegated Toh^et Soap. — Soft water 3 qts. ; nice whita bar soap 3 lbs. ; sal-soda 2 ozs. ; Chinese vermilion, and Cliinese blue, of each, as much as will lie on a 5-cent piece ; oil of sassafras \ oz.
Shave the soap fine, and put it into the water as it begins to boil ; when dissolved, set it from the fire ; take out a cup of the soap and stir in the vermilion ; take out another cup of the soap and stir in the blue ; then pour in one of the cups and give two or three turns only with the stirring stick ; then put in the other in the same way ; and finally pour into a suitable box ; and when cold it can be cut into bars ; or it can be run in moulds, if desired ; it will become hard in a short time ; giving most excellent satisfaction. If stirred thoroughly, after putting in the colors, il would be all of a mixed color ; but giving it only two or three turns, leaves it in streaks, most beautiful.
Soap manufacturers generally use soda, in preference to wood-ashes, because less troublesome ; and to make it mora caustic, or, in other words, to absorb the carbonic-acid-gas, they must put about pound for pound of recently slacked
lime with soda-ash, or sal-soda ; dissolving by heat or stirring; or by both; using sufficient water to make the lyo support a Iresh lain egg, and drawing it off clear of the lime sediment. Thirteen hundred pounds of thetunow, ortheieabouts, with the lye, makes one ton of white boap ; and yellow soap, by using ten hundred of tallow and luiec hundred and fifty of yellow rosiu, for each ton, boiling »vitli the \ye. until they unite ; then pouring into frames, luauo to fit one upon another, to cool and harden ; finally uiicing off one frame at a time, and with a wire, having a handle at each end to draw it with, cut into slices, then baid, and cording up, as wood, to dry. If wood-ashes are useci, plenty of lime must be put into the bottom of the leach.
low, to avoid both :
Take your tallow and put a little bees-wax with it, especially a, your bees-wax is dark and not lit to sell ; put into a suitable kettle, adding weak lye and gently boil, an hour or two each day for 3 days, stirring aud skimming well ; each morning cutting it out and scraping off the bottom which is soft, adding fresh lye (be sure it is not too strong) 1 or 2, or 3. gals., according to the amount of tallow. The third uiorning use water in which alum and saltpetre is dissolved, at the rate of 1 lb. each, for 30 lbs. of UiUow ; then simmer, stir, and skim again ; let cool, and you can lake it off the water for use.
two pounds for each dozen candles.
Saltpetre and alum are said to harden lard for candles; but it can be placed amongst the humbugs of the day But I will give you a plan which is a little shorter for hardening tallow ; either will work well, take your choice :
2 Tatlow — To Cleanse and Bleach. — Dissolve alum 5 lbs., in water 10 gals., by boiling; and when it is all dissolved, add tallow 20 lbs. ; continue the boiling for an hour, constantly stir ring and skimming ; when sufficiently cool to allow it, strain through thick muslin ; then set aside to harden ; when taken ft cm the water, lay it by for a short time to drip.
Dip or mould, as you please, not expecting them to ''run" in summer nor " crack" in winter. They will also bura very brilliantly, at which, however, you will not be surprised when you consider the amount of filth thrown off ia cleansing.
pundcDt of the American Agriculturalist says :
" 1 think it would be well to call the attention of farmers to the use of coal-tar as a paint. The tar produced in coal gasworks is extensively used in England for painting fences, out buildings, &c. ; and is being introduced in this country, also. It necer alters by exposure to the weather ; and one or two goon coats will last for many years. It is the cheapest and best blues paint that can be used. Our buildings are painted with it ; all our apparatus also ; and even the wrought-iron pipe we place iu the ground is coaled with it. I think if its advantages were fully known, it would be generally used throughout the United States. The Government soak the brick used in building the fort at Throg's Neck in this tar, which renders them impervious to water ; and posts painted with it are protected from rot, when in the ground, as effectually as if they had been charred."
I know this tar is much more effectual than charring, and is not one-tenth the trouble. There are posts near this city, which have now been set over ten years, and yet no appearance of decay. The coating is still periect also.
offensive smell, from the heat of the sun.
No persons should allow themselves to set a single past without its application, and farmers who are putting out uiuch fence, cannot possibly be so short-sighted as to neglect it alter it once comes to their notice.
it is doubly important to Railroad-Companiea from the fact that these roads run through the most level portions of 30untry, and consequently the most swampy and wet, therefore fence posts are the more liable to rot. The mode of application is as follows :
Have a large iron kettle so arranged tiiat you can make aua keep the tar hot, then, after having removed the bark, if any, 6ft the end of the post into the tar ; and if the tar is not suraciently deep to take the post into it as far as you wish to tar it have a swab of cloth tied upon a broom-handle or other slick, and swab it up at least 6 to 10 inches above the ground-line when the post is set ; then lift up tlie post, letting it drip a mo ment, and lay it away upon rails or poles placed for that pur pose, not allowing them to touch each other until dry.
Two men will tar about five hundred posts in one day ; and one barrel of tar will be sufheient for that number Who then will hesitate to adopt its use 'i especially when the tar can be purchased at the g:is-works for about two dollars per barrel
MEATS— TO preserve-Beef— To PiCKLK for LoNd h^EKPiNG. — FiKST, thoroughly rub salt into it and let it remain III bulk for 24 hours to draw off the blood. Second, take it up U;tting it drain, and pack as desired. Third, have ready a pickle prepared as follows : — For every 100 lbs. of beef, use 7 lbs. 01 salt ; saltpetre and cayenne pepper, of each 1 oz.; molasses 1 ^i., and soft water 8 gals.; boil and skim well; and when cold pour it over the beef.
This amount will cover one hundred pounds, if it ha oecu properly packed. I have found persons who use noth mg but salt with the water, and putting on hot, scalding again at the end of three weeks and putting on hot again. The only object claimed for putting the brine on the meat while hot, is, that it hardens the surface, which retains tho ■\uices, instead of drawing them oif.
2. The Michigan Farmer's Method. — Is, " for each 100 lbs. of beef, use salt 5 lbs.; saltiwtre i oz. ; brown sugar 1 lb.; dissolve in sufficient water to cover the meat — two weeks after take up, drain — throw away the brine— make more the same as first, it will keep the season through — when to be boiled for eating, put into boiling water — for soups into cold water."
I claim a preference for the first plan, of drawing oiF the blood before pickling, as saving labor ; and that tho cayenne and saltpetre improves the flavor and helps preserve; and that boiling and skimming cleanse the brine very much. Of late years I pursue the following :
3. Beef — To Pickke for Winter or Present Use, and «"OR Drying. — Cut your beef into sizable pieces, sprinkle a little salt upon the bottom of the barrel only, then pack your heo.F without salt amongst it, and when packed pour over it a brriv made by dissolving G lbs. of salt for each 100 lbs. of beef in just Bufflcieut cold water to handsomely cover it.
You will find that you can cut and fry as nice as fresh, for a long time ; just right for boiling, also ; and when it gets a little too salt for frying, you can freshen it nearly as nicely as pork, for frying purposes, or you can boil of it, then make a stew for breakfast, very nice indeed. By the other plan it soon becomes too salt for eating, and the juices are drawn oflF by the salt. In three weeks, perhaps a littie loss, such pieces as are designed for drying will be ready to hang up, by soaking over night to remove the salt from the outside. Do not be afraid of this way; for it is very nice for winter and drying purposes; but if any is loft until
Long keeping.
4. Mutton Hams — To Pickle for DRvrNO. — First take weak brine and put the bams into it for 2 days, then pour o8 and apply the following, and let it remain on from 2 to 3 weeks, according to size : For each 100 lbs.; take salt 6 lbs. ; saltpetre 1 oz. ; saleratus 2 ozs. ; molasses 1 pt. ; water 0 gals., will cove> these if closely packed.
The saleratus keeps the mutton from becoming too hard.
5. CuRiNO, Smoking, and Keeping Hams. — Rosb Cottage, Muncie, Ind., Nov. 26th, 1859 : I noticed an article in the Gazette of yesterday, headed as above, from the pen of Mr. Alexander Brooks, taken from the Rural New Yorker^ and as I have some useful experience in that line, I desire to suggest my plan for curing and keeping :
To a cask of hams, say from 25 to 30, after having packed them closely and sprinkled them slightly with salt, I let them lie thus for 3 days ; then make a brine sufficient to cover them, by putting salt into clear water, making it strong enough to bear up a sound esrg or potatoe. I then add i lb. of saltpetre, and a gallon of molasses ; let them lie in the brine for G weeks — they arc then exactly right. I then take them up and let them drain ; then while damp, rub the flesh side and the end of the leg with finely pulverized black, red, or cayenne pepper; let it be as fine AS dust, and dust every part of the flesh side, then hang them ip and smoke. You may leave them hanging in the smokejouse or other cool place where the rats cannot reach them, as they are perfectly safe from all insects ; and will be a dish fit /or a t'rince, or an American citizen, which is better. Respectfully yoiu-s,
market.
If Grocers will take this plan for preparing their hamg and shoulders, there will be no need of sacking; and such as they buy in during the summer should recieve a coat of pepper immediately, to prevent annoyance from flies.
6. T. E. Hamilton's Maryland Method. — The hams of Maryland and Virginia have long enjoyed a wide celebrity. At one of the exhibitions of the Maryland State Agricultural Society, four premiums were awarded for
by Mr. T. E. Hamilton, from the following recipe :
" To every 100 lbs. take best coarse salt 8 lbs. ; saltpetre 2 ozs ; brown sugar 2 lbs.; potash IJ ozs.; and water 4 gals. Mix the above, and pour the brine over the meat, after it has lain in the tub for some 2 days. Let the hams remain G weeks in the brine, and then dry several days before smoking. I have generally had the meat rubbed with fine salt, when it is packed down."
potash keeps it from drying up and becoming hard.
7. Pork — To Have Fresh from Winter Killing, for Summer Frying. — Take pork when killed in the early part of the winter, and let it lay in pickle about a week or 10 days ; oi until just sufficiently salted to be palatable ; then slice it up and fry it about half or two-thirds as much as you would for present eating ; now lay it away m its own grease, in jars properly covered, m a cool place, as you would lard.
When desired, in spring or summer, to have fresh pork, take out what you wish and re-fry suitable for eating, and you have it as nice as can be imagined. Try a jar of it, and know that some things can be done as well as others. It is equally applicable to hams and shoulders, and I have no doubt it will work as well upon beef, using lard sufficient to cover it. So well satisfied am I of it that I have put in beef-steak, this spring, with my fresh ham, in frying for »ummer use. It works upon the principle of canning fruits to exclude the air, I put in no bone.
8. Salt Pork for Frying — Nearly Equal to Fresh. — For the benefit of thoaa who are obliged to use considerable salt pork, the following method much improves it for frying :
Cut as many slices as may be needed; if for breakfast, the mght previous, and soak till morning in a quart or two of milk ftnd water, about one-half milk, skimmed-niilk, sour milk, or buttermilk ; — rinse till the water is clear and thee Ay. It is nearly or quite as nice as fresh pork, — both the fai and lean parts.
frying, as it makes such a nice imitation of fresh fish.
9. Fresh AIbat — To Keep a Week or Two, in Summku.— Farmoi-s or others, living at a distance from butchers, can keep fresh meal very nicely, tor a week or two, by putting it into sour uiilk, or birtter-milk, placing it in a cool cellar. The bone or fat flced not be removed.
10. Smoked Meat — To Preserve for Years, or vor Sea Voyages. — How often are we disappointed in our hopes of having sweet hams during the summer 1 After carefully curing and smoking, and sewing them up in bags, and whitewashing them ; we often find that either the fly has commenced a family in our hams, or that the choice parts around the bone are tainted, and the whole spoiled.
Now this can be easily avoided, by packing them in pulvei ized charcoal. No matter how hot the weather, nor how thick the flies ; hams will keep, as sweet as when packed, loi years. The preservative qualityof charcoal will keep Ihemtill chArcoal decays ; or sufficiently long to have accompanied Cook three timea around the world.
11. The Kural New Yorker's Method.— It says ; " lu the Sprifg, cut the smoked ham in slices, fiy till partly done, pack in a stone jar alternate layers of ham and gravy. If the Lam should be very lean, use lard for gravy. Be sure and fry the ham in the lard, so that it will be well seasoned. When wanted for use, take up, finish frjdng, and it is ready for the table."
enough, it is so good and handy.
12. The New England Farmer's ** Saving his Bacon." — About a couple of years ago, we were entertained, at the house of a friend, with a dinner of eggs and bacon. We complimented our host on the superior quality of his bacon ; and were curious to inquire the way to like success in the preparation of a dainty article of diet, though one chat is better fitted for the palate of an epicure than for the stomach of a dyspeptic. To our surprise we were informed that that portion of our meal was cooked eight months before.
Upon asking for an explanation, ho stated that it was h'la practice to slice and frj' his bacon immediately on its being cured, an«l then pack it in its own fat. "When occasion came for using it, the slices, slightly re-fried, have all the freshncfsa and flavor of new bacon just prepared. By this precaution, our friend always succeeded in " Saving 7m bacon," fresh and sweet, through the hottest of weather. — AVw England Farmer.
[ also find it ucceesary to put in lard occasionally as you »re frying, as there is not generally enough brought out by the iVying to fill the crevices between the slices, which mu<»* be filled.
CANNING FRUITS— Peaches and Pears.— After paring and coring, put amongst them suflBcient sugar to make them palatable for present eating,— about 3 to 4 lbs. only for each bushel ; let them stand a while to dissolve the sugar, not using ftuy water ; then heat to a boil, and continue the boiling, with care, from 20 to 30 minutes ; or sufficiently long to heat through which expels the air.
Have ready a kettle of hot water, into which dip the can long enough to heat it ; then fill in the fruit while hot^ corking it immediately, and dip the end of the cork intr the " Cement for Canning Fruits." When cold it is bes to dip the second time to make sure that no air holes are left which would spoil the fruit. All canned fruits are to be kept in a very cool cellar.
2. Bkhries, Plums, Cherries, &c. — Raspberries, blackberries, whortleberries, currants, cherries, and plums, need not bfc boiled over 10 to 15 minutes ; using sugar to make palatable, in (ill cases ; as it must be put in some time, and it helps to preserve the fruit,
Strawberries are so juicy, and have such a tendency to fermentation, that it is almost impossible to keep them I have found it absolutely so, until I adopted the plan of using the amount of sugar above named ; if others can do wich less, they can benefit the public by telling me how tney do it.
Or what I think best, is to use a little salt, and put them into haH-gallon jugs ; for we want them in too great quantiti«ffl t« jtop on a few glass jars, such as we use for othei
fruits ; as for tin cans, I never use them ; if you do use tin cans for tomatoes it will not do to use salt with them, aa ?t has a tendency to cause rust.
From four years experience with, not only strawberries, but peaches, cherries, raspberries, pine-apples, &c., without losiug a single jar, the flavor being also perfect : Use only self-sealing glcm jars. While the fruit is heating, keep the jars filled with hot water. Fill up to the brim, and seal immediately.
As it cools a vacuum is formed which prevents bursting. In this way every kind of fruit will retain its flavor. Sometimes a thick leathery mould form, on the top — if so, all the better.
CATCHUP— Tomato Catchup— Take perfectly ripe tomatoes \ bushel; wash them clean and break to pieces; then put over the fire and let thena come to a boil, and remove from the fire ; when they are sufficiently cool to allow your hands in them, rub through a wire sieve; and to what goes through, add salt 2 tea-cups ; allspice and cloves, of each, ground, 1 tea-cup ; best vinegar 1 qt. Put onto the 'fire again and cook 1 hour, stirring with great care to avoid burning. Bottle and seal for use. If too thick when used, put in a little vinegar. If they were very juicy they may need boiling over an hour.
This recipe is from Mrs. Hardy, of the American Hotel, Dresden, 0., and is decidedly the best catchup which I have ever tasted ; the only fault I have ever heard attributed to it was, " I wish we had made more of it." " We have not got half enough of it," &c. But there are those who cannot use tomatoes in any shape ; such persons will, undoubtedly like the following :
2. Currant Catchup. — Nice fully ripe currants 4 lbs. ; sugar 1^ lbs.; cinnamon, ground 1 table-spoon ; salt, with ground cloves and pepper, of each 1 tea-spoon ; vinegar 1 pt.
PKESER\'ES — Tomato Preserves. — As some persons will have preserves, I give them the plan of making the most healthy of any in use :
Take ripe, scalded and peeled tomatoes 13 lbs. ; nice, scalding hot molasses 1 gal. ; pour the molasses upon them and let stand 12 hours i then boil until they are properly cooked ; now skim out the tomatoes, biit continue boiling the syrup until quite thick ; then pour again upon the tomatoes and put away as otlier preserves. A lable-spoon of ginger tied up in a bit of cloth and boiled in them, gives a nice flavor ; or the extracts can be used ; or lemon peel, as preferred — if sugar is used, pound for pound is the amount.
But I prefer to put them, or any other fruit, into jugs, cans, or bottles, which retains the natural flavor and does not injure the stomach, which all preserves do, to a greater or less extent. Yet I give you another, because it does so nicely in place of citron, in cakes.
Cakes. — The harder part of warter-melon, next the skin, made into preserves with sugar, equal weights ; cooking down the syrup rather m<jre than for common use, causes it to granulate, iike citron, which is kept for sale.
This chopped fine, as citron, makes an excellent substitute for that article ; and for very much less cost. Call in the neighbors, to help eat about a dozen good sized melons, knd you have outside enough for the experiment ; and if the Doctor is near he will help without a fee! They are Dice, also, in mince-pies in place of raisins.
CURRANTS— To Dry with Sugar.— Take fully ripe cur rants, stemmed, 5 lbs.; sugar 1 lb.; put into a brass kettle, stirriug at first, then as the currants boil up to the top, skim them off; boil down the juicy syrup until quite thick and pour it over tiie currants, mixing well ; then place on suitable dishes, and dry them by placing in a low box over which you can place musketo-bar, to keep away flies.
When properly dried, put in jars and tie paper over them. Put cold water upon them and stew as other fruit for eating or pie-making, adding more sugar if desired.
TIN- WARE— To Mend by the Heat of a Candle.— Take a vial about two-thhds full of muriatic acid, and put into it, little bits of sheet zinc, as long as it dissolves them ; then put in a crumb of sal-ammoniac and fill up with water, and it is ready to use.
with the preparation ; tbcn put a piece of Bhoet zinc orev the hole and hold a lighted candle or spirit lamp under the place, which melts the solder on the tin and causes the zinc to adhere without further trouble. Wet the zinc also with the solution. Or a little solder may be put on in place of the zinc, or with the zinc.
WATER FILTER— Home-made.— Rainwater is mucli healthier than hard water as a beverage; and the following will be found an easy and cheap way to fit it for drinking purposes :
Have an oak tub made, holding from half, to a barrel, according to the amount of water needed in the family; let it stand en end, with a faucet near the bottom; or, I prefer a hole through the bottom, near the front aide, with a tube in it which prevents the water from rotting the outside of the tub ; then put clean pebbles 3 or 4 inches m thicknest* over the bottom of the tub ; now have charcoal pulverized to the size of small peas {tLi>t made from hard maple is best) and put in half a bushel or so it a lime ; pound it down quite firmly, then put in more and pou id again until the tub is filled to within 8 mches of the top ; a.*d again put on 2 inches more of pebbles; then put a piece of ck ja wliite flannel over the whole top as a strainer.
The flannel can be washed occa.sionally, to remove Cxq impurities collected from the water, and it might be weU to put a flannel between the pebbles and flannel at the botU.m also. When the charcoal Decomes foul, it can be rene^.ed as before, but will work a whole season without renewiag. Put on your water freely until it becomes clear ; when you will be as well satisfied as you would be if it run through a patent filter, costing six times as much as this.
A large jar to hold the filtered water can be set in an .cebox if preferred ; or an occasional piece of ice can bt put in the water ; but if the filter is set in the cellar, v*s it should be, the water will be sufl&ciently cool for ht ilth. This makes a good cider filter, also, first straining the < ider hrough cotton to free it from the coarsest pomace.
TIRE — To Keep on the Wheel. — A correspond at of ♦he Southern Planter e,2L^% : " I ironed a wagon some years ago for my own use, and before putting on the tires I filled the fellies with linseed-oil ; and the tires have worn on h, and were never loose. \ ironed a buggy for my own use seven years ago, and the tires are now as tight as when \ at oa
My method of filling tho fellies with the oil is as follows .
I use a long, cast iron oil-heater, made for the purpose ; the cil is brouglit to a boiling lieat, llie wheel is placed on a stick, so as to hang in the oil, each felly an hour, for a common sized felly. The timber should be dry, as green timber will not take oil. Care should be taken that the oil be not made hotter than a boiling heat, in order that the timber be not burnt. Timber oliUed with oil is not susceptible to water, and is much more durable."
I was amused some time ago when I told a blacksmith how to keep tires tight on wheels, by his telling me it was a profitable business to tighten tires ; and the wagon maker will say it is profitable to him to make and repair wheels — but what will the farmer, who supports the wheel-wright and the blacksmith say? The greatest good to the greatest u umber, is my motto.
with good effect :
Water 10 gals. ; stone lime 20 lbs. ; flour of sulphur 2 lbs Boil in an iron kettle ; after settling, the clear part is to be poured off and sprinkled, freely, upon the weedy walks.
CEMENTS — Cement fok China, &c., which Stands Firb AND Watek. — With a small camel's-hair brush, rub the broken edges with a little carriage oil- varnish.
watei .
2. Russian Cement. — Much is said about cements; but there is probably nothing so white and clear, and certainly nothing better than he following :
Russian isinglass dissolved in pure soft water, snow water is bes>; for it takes 12 hours to soften it by soaking in pure soft water, then considerable heat to dissolve it ; after which it is applicable to statuary, china, glass, alabaster, «&c., &c.
In all cements the pieces must be secured until dry. It i< easy to reason that if twelve to fifteen hours are required lo 8oft«u this isinglass that no dish- washing will ever effect
it. You may j udge from the price whether you got the Russian, for thirty-seven cents per ounce, is as low as the genuine article can be purchased in small quantities, whilst the common, bear a price of only from ten to twelve cents_ »nd even less.
3. Cement, Cubap and Valuaule. — A durable cement ii Diade by burning oyster-shells and pulverizing the Vimc from them very fine; then mixing it with white of egg to a thick paste and applying it to the china or glass, and securing the pieces together until dry.
When it is dry, it takes a very long soaking for it to become soft again. I have lifted thirty pounds by the stom of a wine-glass which had been broken, and mended with this cement. Conimou lime will do, but it is not so good ; either should be fresh burned, and only mix what is needed, for when once dry you cannot soften it.
4. Cement — Water-Proof, for Cloth or Belting.— Take ale 1 pt. ; best Russia isinglass 3 ozs. ; put ihem into a common glue kettle and boil until the isinglass is dissolved ; then add 4 ozs. of the best common glue, and dissolve it with the other; then slowly add IJozs. of boiled linseed-oil, stirring all the time while adding, ajid imtil well mixed. When cold it will resemble India-rubber. When you wish to use this, dissolve what you need in a suitable quantity of ale to have the consistence of thick glue. It is applicable for earthenware, china, glass, or leather ; for harness ; bands for machinery ; cloth belia tor cracker machines for bakers, &c., &c. If for leather, shave olf as it for sewing, apply the cement with a brush while Juit, laying a weight to keep each joint firmly for 6 to 10 hoars, oj over night.
This cement will supersede " Spaulding's Prepared Glue/' and all the white cements you can scare up, if you use good articles to make it of, — not less than thirty or forty cents a pound for common glue, and three shillings per ounce for the Russian isinglass ; but the expense of thii« will cause it only to be used when dampness is to be contended with.
If you have not a glue kettle, take an oyster can ana punch some holes through the top of it, putting in a string to suspend it on a stick in a common kettle of boiling water, and keep it boiling in that way.
5. Cement, or Fu}{niture Glue, for House Use. — To mend marble, wood, glass, china and ornamental ware— take water 1 gal. ; nice glue 8 lbs ; white lead 4 ozs. ; whisky 3 qta.
Mix by dissolving the glue in the water ; remove from the firo and stir in tlie white lead, then add the \»hisky, which keeps it fluid, except in the coldest weather. Warm and stir it up when applied.
DLssolvo the glue by putting it into a tin kettle, or dish, ooutaining the water, and set this dish into a kettle of water, to prevent the glue from being burned ; when the glue is all dissol /ed, put in the lead and stir and boil until all is thoroughly mixed ; remove from the fire, and, when coo^ enough to bottle, add the alcohol, and bottle while it is yet warm, keeping it corked. This last recipe has been sold about the country for from twenty-five cents to five dollars, and one man gave a horse for it.
7. Geuman Cement. — Two measures of litharge, ami 1 each of unslacked linic and flint glass; each to be pulverized separately before mixing ; llieu to use it, wet it up with old drying-oil.
8. Scn.\r-BooK Paste, or Cement. — A piece of common glue, 2 square inches ; dissolve it iu water, adding as much pulvt.'rized alum, iu weight, as of the "glue ; uow mix fiour i^ teaep(j():i in a little water; stir it in and boil. When nearly cool slir in oil of lavender 2 tea-spoons.
Cement— Pueventinq Leaks about Chimneys, &c. — Dry (?and 1 pt. ; ashes 2 pts. ; clay dried and pulverized 3 pts. ; all to DC pulverized and mixed into a paste with linseed-oil.
Apply it while soft, as desired, and when it becomes hard, water will have no effect upon it. It may be used for walks, ind I think it would do well in cisterns, and on roofs, &c.
MAGIC PAPER.— Used to Transfeu Figures in E.\tBi?on>ERY, OR Impressions of Leaves for IIerbviuums. — 'lake lard-oil, or sweet-oil, mixed to the consistence of cream, wUh either of the following paints, the color of which is desired : Pruiiian blue, lamp-black, Venitian red or chrome green, either of (vhich should be rubbed, with a knife on a plate or stone until smooth. Use rather thin, but firm paper; put on with a epi;uge and wipe off as dry as convenient; then lay them between nncolored paper, or between newspapers, and press by laying books or some other flat substance upon them, until the fui-plua oil is absorbed, v;hen it is ready for use.
Directions. — For taking off patterns of embroidery place a piece of thiu paper over the embroidery to prevent soiling; then lay on the magic paper, and put on the cloth you wish to take the copy on, to embroider ; piu fast, and rub over with a spoon handle ; and every part of the raised figure will show upon the plain cloth. To Uike impressions* of leaves on paper, place the leaf between two sheets of this paper, and rub over it hard, then take the leaf out and place it between two sheet:^ of white paper; rub again, and you will have a beautii'ul impression of both sides of the leaf or flower. Persons traveling without pen or ink, can write with a sharp stick, placing a sheet of this papar over a sheet of white paper.
RAT DESTROYERS— Rat Exterminatou.— Flour 3 lbs ; water only sufficient to make it into a thick paste ; then dissolve, pliosphorus 1 oz., in butter li oz., by heat. Mix.
This you will leave, thickly spread on bread, whore rata can get at it ; or make into balls, which is preferable, covered or rolled with sugar. If it is desired to sell this article and you wish to color to hide its composition, work into it pulverized turmeric 2 oz. Or r
kud thicken with tiour.
It is found best to make only in small quantities, as the phosphorus loses its power by exposure. Some will object to killing rats about the house ; but I had rather smell their dead carcasses than ta,%te theu: tail-prints, left on every thing possible for them to get at, or suffer loss from their ^oo^A-prints on all things possible for them to devour, or destroy.
shrewdness.
Then §et a few grains of stiychnine, having a little fresh lean meat broiled; cut it into small bits, by using a fork to hold it, for if held by the fingers, they will smell them and not eat it ; cutting with a sharp penknife; then cut a little hole into the bits, and put in a little of the strychnine, and close up the meat together agaip.
4 Rats — To Drive Away Alive. — If you choose t« drive them away alive, take potash pulverized, and put quite plenty of it into all their hole3 about the house. lif the potash is pulverized and left in the air, it becomes pasty ; then it cau bo daubed on the boards or planks, where they come through into rooms.
Thoy will sooner leave, than be obliged to have a continual re-application of this " Doctor Stuff," every time they go through their holes. S«e " Potash to Make."
5. Scotch snufF, or pulverized cajrenne pepper, mixed tojgether, or separate ; if freely put into their burrowing-holes, will certainly send them off, at a sneezing pace.
*' Mix carbonate of barytes 3 ozs., with grease 1 lb." It produces great thirst, consequently water must be set by it, for death takes place immediately after drinking, not giving them time to go back to their holes. I obtained this at such a late day, that 1 have not had opportunity of testing it Be sure that no other animal can get at it, except ruts . and mice J for it is a most deadly poison. Should this be found as effectual as recommended, it will prove just the thing for rat-killing, as they can be gathered up and carried away, thus avoiding the stench arising from their dead carcasses.
FISH— Art of Catching.— ilix the juice of lovage or smellage, with any kind of bait, or a few drops of the oil of rhodium. India cockle also, (Coculus Indicus,) is sometimes mixed with flour dough and sprinkled on the surface of still water. This iutsxicates the fish and makes them turn up, on top of the water. Mullein seed, pulverized, and used in place of the India Bcokle is about equal to that article.
many fish. Oil of rhodium is the best plan.
'* It is generally supposed," says Mr. R. I. Pell, '• that fish are not possessed of the sense of smell. From the following experiments I am convinced they are : I placed a hook, well baited with an angle-worm, enticingly before a <?CTch weighing one and a half pounds ; he did not take the
least notice of it. It was ./ithdrawn, and a di*op of rkodiob. brought in contact with it, when it was dropped very carefully several feet behind him ; he immediately turned and Beized the bait. This experiment was several times repeated, with like success. It has been denied that fish havo the sense of hearing. I find many varieties very sensitive to noise, and by numerous experiments am convinced thai Ihcir sense of hearing is acute."
STRAW AND CHIP HATS— To Varnish Black — Bert alcohol 4 ozs.; pulverized, black sealing-wax 1 oz.; put thf m into a vial, and put llie vial into a warm place, stirring or fcuakin^ occasionally, until the wax is dissolved ; apply it when warm by means of a soft brush, beiore the fire or in the sun.
It gives stifiuess to old straw hats or bonnets, n.akes a beautiful gloss, and resists wet; if anything else is required, just apply it to small baskets also, and see how nicely they will look.
3. Sthaw Boxnets— To Color a Beautfful Slate. — First soak the Ix^nnet in rather strong warm suds for fifteen minutes, *Jii3 is to remove sizing or stitl'ening; then rinse in warm water o get out the soap ; now scald cudbear 1 oz., in sufficient wafei o cover the hat or bonnet — work the bonnet in this dye at 180 .egrees of heat, until you get a light pm-ple ; now have a bucket of cold water blued with the extract of indigo, about i oz., and work or stir the bonnet in this, until the tint pleases.
Dry, then rinse out with cold water and dry again, in the shade. If you get the purple too deep in shade, the final slate will be too dark. See " Extract of Indigo, or Chemic."
ffood common lime ; using only f or four-fifths, at most, as much ime as needed for common work — the other fourth or fifth is to be water-lime; and not to be put in only as used. Th^s sand must be coarse, and free from loam or dirt.
This white-wash is to be colored the tint desiretl for the work. Be sure to make color-wash enough at ono time, or you will find it hard to get the shades alike ; saving « little of the white-wash without color, to pencil the seams, and also for specking, as mentioned below. The col»rs used ara lamp-black, Spanish-brown, or Venetian-red, as preferred, aB<9 these are cut or dissolved in whisky; then pitting int* *• white-wash to suit
ifhcn these waslies are all prepared, wet up ns much of ijre mortar as can be put on in 20 to 40 minutes, and mix in the fourth or fifth of the cement, and put en as fast as possible ; first Tfetting the wall very wet with water. Some cement will set in SO and some iu 40 to 50 minutes. AVhen you see the time necessary for the kind you are using, act accordingly, and only mix the cement into as much mortar as your help will put on before it sets ; beginning at the top of the wall with your scaffolding ami working down, which prevents too much specking from the colors. Have a man to follow right after with a float, keeping the stucco very wet while floating down level and smooth ; and the longer it is floated and wet, the better will be the job. Even Rfter it 13 floated down well, keep a man wetting it with a brush until you get the whole line on, around the house, as the wateriaie must be kept quite wet for some considerable time, to set properly. Heed this caution, and if water never gets in br .ind the plastering from bad cornice or leaky roofs, it will neve peel oS". When this line of scaflblding is plastered, take cute .ough of the color-wash, running it through a sieve, and go over the
{)lasteriL,g ; lamp-black alone gives it a bluish slate color ; if a ittle of the brown is added with the black, it will be a little reddish, and if the red is used without the brown, it will be quite retl. I prefe: sufficient of the black only to make a gray stone color. A brovn, however, looks exceedingly well. If you choose, you can make one-half of the color-wash darker than the other — having laid it off" into blocks resembling stone, by means of a straight-edge, and piece .of board about half an inch thick, paint every other block with the darker wash to represent different shades of stone. Some of our best buildings are done in this way, and look well.
Then to give it a granite appearance, take a small paint-brush and dip it mto the white-wash, saved for this purpose ; strike it across a hammer-handle so as to throw the specks from the brush upon the wall, then the same with black and red. Pencil ths seams with the white-wash, which gives it the appearance of mortar, as in real stone-work.
No)^ jou are ready to move down the scaffold, and go ♦vei the same thing as before. After the colors have been iisso'ved with spirits, they can be reduced with water, or what is better for them and the color-wash also, is skimmedmilp- ; and where milk is plenty, it ought to be used ii? place of water, for white-wash or color-washes, as it helps to resist the weather, and prevents the colors from fading — see " P-^int, to Make without Lead or Oil," which gives you the philosophy of using milk. Speck quite freely with the wh'te, then about half as much with the black, and then ratJier fr.Qe again with the red. The proportion of lime,
probably, should not exceed one, to six or seven of sand Our University buildings, represented io th« frontispiece^ except the Laboratory, and Law-building, which have been more recently put up, are finished with it, and also whole blocks in the busincsH part of our city
J*rof. Douglas^' house is probably the prettiest color of ny in the city — an imitation of '' Frcc-stone," made with amp-black, yellow ochre, and a larger proportion of Spaiiish wown, But all will have a preference for some special color ; then, with a little ingenuity and patience, nearly any coloieJ stone can be imitated.
GRAVEL HOUSES— To Make— PsoportioiNS oy Lime, Sand, and Gravel. — It has become quite common to put up gravel houses : and many persons arc at a great loss to know what proportion of materials to use. Various proportions hare ])cen proposed ; but frwm the fact that the philosophy was not explained, no real light was given upou the subject.
All that is required to know, is, that saud and lime are to be used in proportion to the size of tiie grav^el, — say for 15 bushels of clean gravel, from the size of peas up to that of hen's eggs, it will take about 3 bushels of clean sharp sand and 1 of lime to fill the crevices without swelling the bulk of the gravel. If liie gravel is coarse, up to 5 boshels of sand may be required, bet the lime will not need to be increased but very little, if any. Then the philosophy of the thing is this — about 1 to 1^^ bushels of lime to 15 bushels of gravel, and just Mud enough to fill me crevices without increasing tlie bulk as above mentioned.
If tho gravel is fi*oe of dirt, the sand I'lso clean, and tlie weather dry, the walls can bo raised one font each day, if you have help to do that amount of labor.
Some prefer to make the gravel and sand ivto mortar and press it into bricks ; then lay into walls, but the \rall must be stronger if laid up solid, in board frames, laade to raise up as required.
Many persons argue for the eight-square or octofoo bouse ; but I like the square form much the best, carryim^ up the hall and main partiton walls of the same material. Tha eight square house looks like an old fort, or water tant. and 13 very expensive to finish ; costing much more than toe Bame room with square an^.^s; for mechanics cannot put up cornice outside, or in, in ws than double the time ie» quired for making the common square mitre.
Prof. Winchell, of the Univei"sity, and State Geologist, jn this city, has put up one of the octagons which looks Weil, however, fur the style of Jinuh is what attracts attention, instead of the style of form.
WHITEWASHES AND CHEAP PAINTS.— Brilliant Stucco Whitewash — Will Last on Brick o& Stone, Twenty to Thirty Years. — Many have hfard ot the brilliant stucco whitewash on the cast end of the President's house at Washington. The following is a recipo for it, as gleaned from the National lutellicjencer, with some additional improvements learned by experiments :
Nice unslaked lime ^ bushel ; slake it with boiling water ; cover it during the process, to keep in the steam. Strain the liquid through a fine sieve or siraiuer, and add to it, salt 1 peck ; previously well dissolved in water ; rice 3 lbs. — boiled to a thin paste, and stirred in boiling hot ; Spanish whiting ^ lb. ; clean nice glue 1 lb., which has been previously dissolved by soaking it well, and then hanging it over a slow fire, in a small kettle, immersed in a larger one filled with water. Now add hot water 5 guls.,to the mixture, stir it well, and let it stand a few days covered fr»m the dirt.
it should be put on not. For this purpose it can be kept in a kettle on a portable lurnace. Brushes more or less small may be used, according to the neatness of job required. It answers as well as oil paint for brick or stone, and is much cheaper.
There is one house in our city which had this applied twelve years ago, and is yet nice and bright. It has retained its brilliancy over thirty years.
Coloring matter, dissolved in whisky, may be put in and made of any shade you like ; Spanish brown stirred in will make red-pink, more or less deep, according to quantity. • A delicate tinge of this is very pretty for inside walls. Finely pulverized common clay, well mixed with Spanish brown, makes reddish stone color. Yellow-ochere stirred m makes yellow wa.sh, but chrome goes further, and makes a color generally esteemed prettier. In all thes i cases the darkness of the shade, of course, is determmed by the quantity of the coloring used. It is difficult to make rules, because taites are different— it would be best to try experiments on a shingle and let it dry. Green mu-it not be mixed with lime. The lime destroys the color, and the color
has un effect on the whitewash, which makes it crack ubd peel. When inside walls have been badly smoked, and you wish to make them a clean, clear white, it is well to squeeze indigo plentifully through a bag into the water you tise, be fore it is stirred into the whole mixture, or blue vitriol pul verized and dissolved in boiling water and put into whitewash, gives a beautiful blue tint. If a larger ."{uantity than five gallons be wanted, the same proportions should be o\y served.
2. Whitewash — VeuY Nice for Iloovrs. — Take whiting 4 lbs. ; white or common glue 2 ozs. ; stand *he glue in cold water over night ; mix the whiting with cold water, and heat the glue until dissolved ; and pour it into the other, hot. Make of a proper consistence to apply with a common whitewash bruslv.
beauty of this whitewash.
3. Paint — To Make without Lead oii On..— Whiting 5 lbs; Bkimmed milk 2 qts. ; fresh slaked lime 2 0Z!"<. Put the lime into a stone-ware vessel, pour upon it a suhic'ent quantity of the milk to make a mixture resembling cream; tlie balance of the milk is then to be addeil ; and lastly the wLitiug is to be crumbled upon the surface of tlie fluid, in wlii'^h it gradually sinks. At this period it must be well stirred in, or ground aa you would other paint, and it is tit fur use.
There may be added any coloring matter that suit* the fancy, (see the first whitewash for mixing colors,) to ba applied in the same manner as other paints, and in » few hours it will become perfectly dry. Another coat may then be added and so on until the work is done. This paint ia of great tenacity, bears rubbing with a coarse cloth, baa little smell, even when wet, and when dry is inodorous. The above quantity is sufficient for fifty-seven yards. — Aj*aapolis Rejfuhhcan.
" We endorse the recip'^. The casein or curd of the milk, by the action of the caustic-lime, becomes insoluble, and has been used, fur time immemorial, as a lute for chemical experiments. It is a good, and, in comparison with white load, a durable paint." — Moorts Rural New Yorker
White lead always requires two, biit some people think because they get a cheap paint that one coat ought to make a good job. Two will generally do with any except white.
4, White Paint— A New Way of Mafnuacturingl — The following was communicated by a man who was formerly a carpenter in the U. S. Navy.
'' During a cruise in the South Pacific, we went into the harbor of Coquimbo ; and as the ship had been out a long time, she was covered with rust from stem to stern. It waa the anxious wish of the commander that she should be roBtored to her original colors ; but on examining the storeroom, it was ascertained that there was not a pound of white lead ia the ship. In this emergency I bethought me of an expedient which concocted an admirable substitute, composed of the following ingredients :
" Air-slaked lime, pulverized until it was of the fineness of flour, which was then passed through a seive. Rice boiled in a large kettle until the substance was drawn eutirel^r out of the grain ; the water, then of a plastic nature, was strained to separate the grain, &c., from the clear liquid. A tub, about the size of a half barr*)l, of the prepared lime and rice-water, was mixed with 1 gallon of linseed-oil ; and the material had so much the appearance oi paint that a novice could not have told the difference.
" The ship was painted outside and inboard with the above mixture (which cost next to nothing,) and never preBcnted a finer white streak on her bends, or cleaner bulwarks and berth-deck than on that occasion, and no other kind of white paint was used during the remainder of the cruise."
5. Black and Green Paint — Durable and Citeap, for OuT-DooR Work. — Any quantity of charcoal, powdered ; a sufflcient quantity of litharage as a diyer, to be well levigated (rubbed smooth) with linseed-oil ; and when uijed, to be thinned with well boiled linseed-oil. The above forms a good black paint.
By adding yellow ochre, an excellent green is produced, which is preferable to the bright green, used by painters, for all garden work, as it does not fade with the sun.
This composition was first used by Dr. Parry, of Bath, on some spouts; which, on being examined, fourteen years afterwards, were found to bo aa perfect as when first put
6. Milk Paint, pok Barns — Any Colok.— ' Mix water lime with skim-milk, lo a pronar consistence to apply with a brush, and it is ready to use. It will adhere well to \vood, whether smooth or rough, to brick, mortar or stone, where oil has not been used, (in which case it cleaves to s(jme extent,) and forma a very hard substance, as durable as the best oil paint. It is too cheap to estimate, and any one can put it on who can use a brush." — Country Oentleman.
Any color may be giVeu to it, by using colors of the tinge desired, dissolving in whisky first, then adding in to Buit the fancy, as in the first recipe.
^To have a good glue always ready for use, just put a bottle two-thirds full of best common glue, and fill up the bottle with common whisky ; cork it up, and set by for 3 or 4 days, and it will dissolve without the application of heat.
It will keep for years, and is always ready to use without heat, except in very cold weather, when it may need to b<> set a little while in a warm place, before using.
2. Imitation of Spalding's Gluk. — First, soak in cold vatei all the glue you wish to make at one time, using only glass, earthen, or porcelain dishes; then by gentle heat dissr'lve the glue in the same water, and pour in a little nitric acid, sufficient to give the glue a sour taste, like vinegar, or from i oz, to 1 oz. to each pound of glue.
The acid keeps it in a liquid state, and prevent« it from spoiling ; as nice as Spalding's or any other, foi a very trifling expense. If iron dishes are used, the acid corrodea them and turns the glue black. Or :
more glue.
This keeps in a liquid state, docs not decompose ; and is valuable for Druggists in labeling; also for house use ; and if furniture men were not prejudiced, they would find it valuable in the shop.
4. Watkr-Proof Glue — Is made by first soaking «.ije glue in cold water, for an liour or two, or until it becomes a \itlle soil, yet retaining its original form ; then taking it from the watei and dissolving it by geutie heal, stirring in a little boiled linBCcd-oU.
mosphere.
FIRE KINDLERS.— To make Tcry nice fire kindlers, take rosin, any quauiity, and meit it, putting in I'urcacb pound being used, from 2 to 3 ozs. of tallow, and when all is hot, stir in pine saw -diist to make very thick ; and, while yet hot, spread it on* al»oul 1 inch thick, upon boards vhich have fine saw-du»t Bpriiikled upon them, to prevent it from sticking. When cold, break up into lumps about 1 inch square. But if for sale, take a thin board and press upon it, while yet warm, to lay it off into 1 inch squares ; this makes it break regularly, if you press the crease sulhciently deep, greasing tiie marking-board to prevent it from sticking.
One of these blocks will easily ignite with a match, and burn with a strong blaze long enough to kindle any wood fit to burn. The above sells readily in all our large towns and cities, at a great profit.
2. Most of the published recipCiS call for rosin 8 lbs.; tar 1 qt.; and 1 gill of turpentine ; but they make a black, sticky mess of stuff, which always keep the hands daubed. On the other hand, this makes a roein-colored kindler, which breaks nicely also when cold-; and they are decidedly a nice thing ; and much more certain to start a fire than shavings. If the tar plan is u.sed, 1 pt. is enough for 5 lbs of rosin.
melt them together with a gentle heat.
AVheu you have prepared a sufficient amout of starch, in the usual way, for a dozen pieces — put into it a piece of the polish the size of a large pea ; more or less, according to large or small washings. Or, thick gum solution (made by pouring boiling water upon gum arabic.) one table-spoon to a pint of starch, gives clothes a beautiful gloss.
PERCUSSION MATCHES— OF THE best quality.— Chlorate of potash f lb.; ghie 3 lbs.; white lead, dry, 5 lbs.; red lead i lb ; phosphorus 2f lbs. Directions. — First put the chlorate into a dish made for the purpose, deep, and of a suitable size to set into a kettle of water, which can be kept on the fire for 2 or 3 dttj a, haying 2 qts. of water on the chlorate ; then put the glue on top of the chlorate water, and let soak until all is perfectly dissolved ; then add the leads and heat up quite hot, and tholougbly mix; let cool and add the phosphoiiis, let it dissolve and
be careful never to heat hot after the phosphorus is added ; sev oc(»8ionallj^ while dipping, and if little particles of phosphortui fires, push it down into the mixture, or put on warm water; il you put on cold water, it will fly all over j-ou. Keep it rathei tliin after the phosphorus is put in, and there will be no danger ; altliough the chlorate of potaah is considered a dangerous article to work with; so is powder, yet wlien you kr.ow how to wirk with them, you can do as s;ifely with one as the other. Wheu dry give them a coat of varnish.
I have been acquainted with a man for about fourteeo years who makes them, and several others for a less time, without trouble or accident. A better match was never made to stand dampness, or bear transportation without setting on fire. I have used and sold them much of the time, and speak from knowledge. One explosion has since taken place.
The plan pursued here in preparing the splints is as follows : Sawed pine timber from four to eight inches each way, is cut off the right length for the match, then one end of it is shaved smooth, with a drawing-knife; the biock is held upon the horse by a brace from the top of the horse head against the back side of the block, so as to be out of tlie way of the knife instead of putting the block under the jaws of the horse head, as the dents made in the end of match timber would not answer; the front edge comes against a strip put on for that purpose ; then glue the other end and put ou brown paper, which holds them togethur when split; machines are used to split with which feeds up the block enough each time the knife is raised, to make tha size of the match when split the other way, or about ten to the inch. These machines cost about fifty doUais, and the work goes ahead like a young saw-mill, by simply turning a crank as shown in the figure.
A A, shows two standards bolted upon a base plank, four feet in length ; these standards support a shaft, with crank and balance wheel D, which is two feet in diameter , the hhaft has upon it an oval wheel, G, which sinks the knife, F, twice in each revolution, the knife passing down through a space in a thin iron strip, H, standing out from the two blocks, C C, under which the match block passes by the drawing of the chain seen to pass over a small drum, P, upon the shaft of the rag wheel, B, the notches being only one-fourth inch apart, and fed up by the hand, M, attached to
MATCH SPHTTINQ MACHINE.
The hand, M, is kept down into the cogs or notches by the little spiral wire spring, K ; the match block, to be split, set3 in the frame forward of the block', I, which has a pin in it to draw back the frame. A\ hen the block of matches is split, this frame goes forward to touch a catch, the same as a saw-mill, which lets anotho^ spring not .seen, raise the hand, M, when the feeding operation ceases. The frame is then drawn back and the same repeated. As the match is *plit they open and require a rounding mortise made through the base plank between the blocks, C C, which allows them to remain in a half circular form — the knife is raised by a line att^iched to a spring pole, T, the knife is screwed upon a piece of cast iron which works in the guide, N, having tho back end firmly fa.stened by a bolt through the standard, 0 This knife stands at right angles with the shaft. When the matches are split and sufficiently dry to work upon, they are dipped in melted brimstone, kept hot, and the match also kept hot on a sheet iron stove, and all the brimstone is thrown oH which can possibly be by jerking the block with the hand, it any brimstone remains upon the end it must be scraped off before dipping into the match composition. Without tho chlora'e, the com position makes a first class
' Friction Match." It ought to be known, ho^ovor, that the match business is au unhealthy occupation, from the poisonous effects of the phosphorus.
STEA.M BOILERS— To Prevtsnt Lime Deposits.— Put intc? 70ur cistern or tank, from ■which the boiler is fud, a suliicienl amount of oak tan-bark, in the piece, to color the water ralhei dark ; run 4 weeks anil renew.
2. Ohio Rivkr Plan. — Sprouts from barley, in malting, are recommended by Capt. Lumm, part owner of a steamboat, and ongineer on the Ohio and Mississippi rivers, to prevent the deposit of lime upon boiUi-s, and ho says tightens up old leaky boilers, also. It may be used in quantities of from '6 pts. to 2 or '3 qts., according to the size of boilers.
When it is put in you must know the quantity of water in the boiler, for unless you heat up quite slow it causes a foaming of the water, and might deceive the engineer about the amount of water in the boiler, but if heat up slow there is no danger of this deception.
?). To Prevent Explosion, with the Reason why •niLY Explode. — At a recent meeting of the Assouatioo for the Advancement of Science, Mr. Hyatt, of New I'ork, presented what we believe to be the true cause. Re presented the following table, showing the rapidity with which pres.'iure is douhleil by only a slight increa.se of heat.
It was stated by Mr. Hyatt, that, from experiments he had made, tliis great, increase of i^resaure could be obtained \& »xto fcren minutes, with an engine at rest. This rapid doubling of pressure, with but a small increase of heat, is clue to the conversion of what is termed latent heat, in steam, into sensible heat if we immerse a thermometer into boiling water, it stands at 212 ; if we place it in steam immediately above the water, it indicates the same temperature. The question then arises, wlial becomca of all the heat which is communicated to the water,
tince it is neither indicated by the water nor oy the steam formed from it? The answer is, it ei>**!r3 the water and couvei-ta it into &t6&m without raising its temperature. One tlwu^and degrees of heat are absorbed in the conversion of water into steam, and this is called its latent heat. And it is the sudden conversion ot latent heat into semihle heat that produces the explosion. If an engine is stopped, even if there is but a moderate fire, if the escape valve is closed, there is a rapid absorption or accumulation of latent heat. The pressure rises with great rapidity, and whou the cn^in'^^L thinks everything is safe, the explosion comes.
That this is the true cause of nearly all the explosions that occur, will be plain to every one who will look at the relations between latent and sensible heat. ]-*rof. Henry and Prof. Silliman, Jr., endorse the view. What, then, ia tlie security against explosions ? Wo know of no securities but these — a sufficiency of water in the boilers^ and the escape valves open at light pressure, when the engine is at rest. — Sprinjjield Republican.
There is no question about the foregoing explanations being founded in true philosophy ; and if engineers will be governed by them, instead of by a desire to hold on to steam for the purpose of getting ah<a<l or of keeping ahead, as the case may be, of some other . boat ; or on land, to save the expense of fuel, not one explosion would take place wncre now there is, at least, a hundred.
A series of experiments have recently been concluded oq the U. S. Steamer Michigan, and a full but voluminous report laid before the Navy Department, upon the subject of steam expansion. It would pay all interested in steam works to obtain and read it.
PLUMS AND OTHER FRUIT— To Pkevent Ln'skcts from Stinoing. — Take new, dry lime, sulphur, and gunpowder, equal parts, pulverized very fine, and throw it amongst the flowers when in luU bloom ; use it freely so that all may catch a little.
This has been tried with success. Working upon the ^►rinciple of pepper, to keep flies from meat. The injury io fiiiit being done while in blossom.
BED-ROOM CARPETS— For Twelve and a h-vlf Cexts FKR Yard. — Sew together the cheapest cotton cloth, the size of the room, and tjwik the edges to the tioor. Now paper the cloth &8 you would the sides o!' a room, with cheap room psiper; piit-
ting a border around the edfi;e 'f desired. The past* will be I 4 better if a little gum arabic is ni.Ked with it. \Vhen tboroughly dry, give it two coats of furniture or carriage varnish, and when dry it is done.
It can be washed ; and looks well in proportion to the quality and figure of the paper used. It could not be ex* pcctcd to stand the wear of a kitchen, for any length of time, but for bed-rooms it is well adapted.
COFFEF — lIoRK Healtht and Better Flavored, fob Onh-Fouutu the Expense of Common. — Coffee, by weiglit 01 measure, one-fourth, rye three-fourths.
Look them over separately, to iiemove bad grains ; then wash to remove dust, draining off the water for a moment as you take it with the hands, from the washing water, putting directly into the browning skillet, carefully stirring, all the time, to brown it evenly. Brown each one separately ; then mix evenly, and grind only as used ; settling with a beaten egg, seasoning with a little cream and sugar as usual.
hundred per cent, more healthy than all coffee.
You may try barley, peas, parsnips, dandelion roots, &c., but none of their flavors are equal to rye. Yet all of thcin are more or less used for coffee.
PICKLING FRL^TS, AND CUCUMBERS— Pickling Ar pi.ES. — Best vinegar 1 gal.; sugar 4 lbs.; apples all it will cover handsomely ; cinnamon and cloves, ground, of each 1 table•poon.
Pare and core the apples, tying up the cinnamon and cloves in a cloth and putting with the apples, into the vinegar and sugar and cooking until done, only. Keep in jars. They are nicer than preserves, and more healthy, and keep a long time ; not being too sour, nor too sweet, but an agreeable mixture of the two. It will be seen below that th«» different fruits require different quantities of sugar and vinegar, the reason for it, is, the difference in the fruit.
apples.
Treated every other way as apples. If they should begin tO ferment, at any time, simply boil down the juice ; the» boil the peaches in it for a few minutes only.
8. Peaches — To Peel. — la peeling small peaches with a knife, too much of the peach is wasted ; but by having a wire-cage, similar to those made for popping corn ; fill the cage with peaches and dip it into boiling water, for a moment, then into cold water for a moment and empty out • P'oing on in the same way for all you wish to peel. This toughens the skin and enables you to strip it oflf, saving touch in labor, as also the waste of peach. Why not, as well as tomatoes?
them again.
5. PiOKLtNG CuccMBERS. — ^Plck cach moming ; stand in weak Drine 3 or 4 days, putting in mustard pods and horseradish leaves to keep them green. Then take out and drain, covering with vinegar for a week ; at which time take out and drain again, puttihg into new vinegar, addins^ mustard seed, ginger root, cloves, pepper and red pepper pods, of each about 1 or 3 oz. ; or to suit different tastes, for each barrel.
The pickles will be nice and bfittle, and pass muster a any man's table, or market. And if it was generally known that the greenness of pickles was caused by the action of the vinegar on the copper kettle, producing a poison, (verdigris,) in which they are directed to be scalded, I think Qo one would wish to have a nice looking pickle at the expense of HEALTH ; if they do, they can continue the bad practice of thus e'-alding ; if not, just put your vinegar on cold, and add your red peppers, or cayennes, cloves, and other spices, as desired ; but the vinegar must be changed once, as the large amount of water in the cucumber reduces the vinegar so much that this change is absolutely necessary ; and if they should seem to lose their sharp taste again, jast »dd a little molasses, or spirit, and all will be right.
Apply in place of paint, not allowing the first coat to get entirely dry until the next is applied ; if it does, a skin is formed which prevents the next from penetrating the «tone. Poorly burned brick will be equally well preserved by the assae lU'ooeiM.
SEALING WAX— Red, Black, aitd Bltje.— Gum Shellac 8 oz.; Venice turpentine 4 ozs.; vermillion 2^ ozs.; alcohol 2 ozs.; camphor gum i oz. Dissolve the camphor in the alcohol, then the Bhellac, addinr the taipentine, and finally the vermillion, be"ng very careful tuat no blaze shall come in contact with its tumcB ; for if it does, it r.-ill fire verj' quickly.
B.OBt be well nibbed into the mixture.
ADVICE— To YouNo men and others, out of e.mI'LOYMENT. — Advice — How few there are that will heai advice at all ; not because it is advice, but from the fact that those who attempt lo give it are not qualified for the work they assume ; or that they endeavor to thrust it upon their notice at an inappropriate time ; or upon persons over whom no control is acceded, if claimed. But a book or paper never give offense from any of these causes ; therefore, they are always welcomed with a hope that real benefit may be derived from their 6uggcf>tions. Whether that end will be attained in this case, I leave to the judgment of those for whom it is intended ; hoping they may find themselves sufficienly interested to give it a careful perusal, and candid consideration. And although my remarks must, in tliis work, be necessarily short, yet every sentence shall he a. text for your own thoughts to contemplate and enlarge upon ; and perhaps, in some future edition of the work, I may take room and time to give the subject that attention which is really its due ; and which would be a pleasure to devote to its consideration.
First, then, let mc ask why are so many young men and other persons out of employment ? The answer is very positive as well as very plain. It is this — indolence, coupled with a dcteimination that they will do some (jreat thing, only And because that great thing does not turn up without effort, they are doing nothing. The point of difficulty is simply tins ; they look for the end, before the beginning. Bu» just consi^.er how few there are that really accomplish any great thing, even with a whole life of industry and economical perseverance. And yet most of vwc youth calculate that their beginning shall be amongst the greats. But as no one comes to offer them their expectations, indolPDce says wait;
and 80 thej are still waiting. Now mind you, as long as your expectations are placed upon a chance offer of something very remunerative, or upon the assistance of others ; even in a small way, so long will you continue to wait in rain. At this point, then, the question would arise, what can be done ? and the answer is equally plain with the other. Take hold of the first job you can find, for it will not find vou. No matter how insignificant it may be, it will be bet■cr than longer idleness ; and when you are seen doing #omething for yourselves, by those whose opinions are worth any consideration, they will soon offer you more and better jobs ; until,. finally, you will find something which agrees with your taste or inclination, for a life business. But re• member that the idle never have good situations offered them. It is the industrious and persevering eriy, who are needed to assist in life's great struggle.
There are a few lines of poetry called " The Excellent Man," which advocates the principles I am endeavoring to advance, so admirably that I cannot deny myself the pleasure of quoting them. The old proverb, " God helps those who help themselves," is as true as it is old, and after all that is said and done, in this country, if in no other, a man must depend on his own exertions, not on patronage, if b« would have or deserve success :
" They gave me advice and counsel In store. Praised me and honored me more and more Said that I only should ' wait awhile,' Oflered their patronage, too, with a smile
But with all their honor and approbation, I should long apo have died of starration, Bad there not come an excellent man. Who, bravely to help me along began
yourself honest, industrious, perserering, and faithful in every trust, and no fears need be apprehended of your final success. Save a part of your wages as a sinking fund, or rather as a floating fund, which shall keep your head above water in a storm ; or to enable you, at no distant day, tft commence a business of your own.
A poor orphan boy, of fourteen, once resolved to save half of his wages, which were only four dollars per month, for this purpose ; and actually refused, even in sickness, although really suflFering for comforts, to touch this business fund. He was afterwards the richest man in St. Louis.
His advice to young men was always this : " Go to work ; save half your wages ; no matter how small they may be, until you have what will enable you to begin what you wish to follow; then begin it, stick to it; be economical, prudent, and careful, and you cannot fail to prosper."
My advice is the same, with this qualification, however; that in choosing your occupation, you should be governed by the eternal principles of right ! never choosing that which, when done, injures a fellow creature more than it can possibly benefit yourself — I mean the liquor traffic. But with the feeling of St. Paul, when he saw the necessity of doing something different from what he had been doing, he cried out, *' Lord, what wiJt thou have me to do ?" Ask your own tastes, being governed by conscience, under the foregoing principles ; knowing that if a person has to learn a trade or business against his own inclination, it requires double dilligence to make only, half speed, and hardly ever meeting with success.
The question to be settled, then, is this : Shall I work the soil : Shall I be a mechanic, teacher, divine, physician, lawyer, merchant, druggist, or grocer, or shall it be something else ? Whenever you make up your mind what it shall be, make it up, also, to be the best one in that line of business. Set your mark high, both in point of moral purity and literary qualificaiiois.
accumulated sufficient to make a fair commencement in your studies ; then prosecute them . in all faithfulness as far as the accumulated means will advance you ; realizing that this increase of knowledge will give you increased power ia obtaining the further means of prosecuting your studies, accessary to qualify you to do one thing only in life.
Nearly all of our best men are self-made, and men of one idea, i, e., they have set themselves to be mechanics, physicians, lawyers, sculptors, &c., and have bent their whole energies and lives to tit themselves for the great work before them. Begin, then ; offer no excuse. Be sure you are on the right track, then go ahead :
Always remembering that industry, in study or labor, will Keep ahead of his work, giving time for pleasure and enjoyment; but indolence is ever behind; being driven with her work, and no prospect of its ever being accomplished.
When you have made your decision, aside from wha-t time you must necessarily devote to lal?or, let all possible time be given to the study of the best works upon the subject of your occupation or profession, knowing that one hour's reading in the morning, when the mind is calm and free from fatigue, thinking and talking with your companions through the day upon the subjects of which you have been reading, will be better than twice that time in evening reading, yet if both can be enjoyed, so much the better ; but one of them must certainly be occupied in this way.
If you choose something in the line of mercantile or trade life, do not put off, too long, commencing for yourself. Better begin in a small way and learn, as your capital increases, how to manage a larger business.
pesides feeding his family.
I knew one also to begin with sixty dollars, and in fifteen months he cleared over four hundred and fifty dollars, besides supporting his family ; then he sold out and lost all, before he again got into successful business.
Tbosc who choose a professional life, wiL hardlj find a place in the Westt, equal to the University of Michigan, Ann Arbor, to obtain their literary qualifications. An entrance fee of Ten Dollars, with Five Dollars yearly, pays for a full Literary, Law, Medical, or Civil Engineering course ; the first requiring four, the two next, two, and the last, three years. [See Frontispiece.]
Or, in the words of the Catalogue : " The University, having been endowed by the General Government, affordi education, without money and without price. There is no young man, so poor, that industry, diligence, and perseverance, will not enable him to get an education here.
*' The present condition of the University eenfirms this view of its character. While the sons of the rich, and cf men of more or less property, and, in large proportion, the sons of substantial farmers, mechanics, and merchants, are educated here, thei'e is also a ver}' considerable number of young men dependent eiitireli/ upon their own exertions — young men who, accustomed to work on the farm, or in tho mechanic's shop, have become smitten with the love of knowledge, and are manfully working their way through, to a liberal education, by appropriating a portion of their time to the field or the workshop."
edly preferable.
And that none may excuse themselves from an effort be. cause somewhat advanced in life, let me say that Doctor Eberle, who wrote several valuable medical works, did not begin his medical studies until forty-five years of age ; and, although I could mention many more, I will only add that I, myself always desired to become a physician, yet circumstances did not favor nor justify my commencement until I was thirty-eight. See the remarks following " Eye Water."
There is no occupation, however, so free and independent as that of the farmer ; and there is none, except parents, capable of using so great an influence, for good or for evil, as that of teacher.
tuace inelmea them to teach, not shrink the responsibility^ but fully qualify for the work; learning also the ways of Truth and llighteousness for themselves ; teaching it through the week-school, by action as well as by word, and in the Sabbath-school, fail not to take their stand for the right, like our President dect ; then when it comes your turn to assist in the government of the State, or Nation, the people will come to your support, as you do to your work — as they have just done to his, (1860); feeling, as now, that the governraeat must be safe in the hands of those who love God — deal honestly with their fellows ; and who, in remembering the Sabbath to keep it holy themselves, are not ashamed — nor forget, to teach the children to love the same God, and reverence His Word. Only think — a SabbathSchool Teacher — a Rail- Splitter — a Boat-man, President of the United States !
Who will hereafter be afraid of common labor ; or, let indolence longer prevent their activity ? when it is only those who begin with small things, and persevere through life, that reach the final goal of greatness; and, as in this case, are crowned with the greatest honor which man can receive — the confidence of his Nation.
Then let Industry take the place of Indolence, beginning to be great, by grappling with the small things of life — be faithful to yourself, and, you may reasonably expect, the end shall, indeed, be great.
And although it could not be expected, in a work of this kind, chat much could, or would be said, directly, regarding a future life, yet I should be recreant to duty if I did not say a vford more upon that subject. It shall be only a word . Be as faithful to God, as I have recommended you ^0 be to yourselves, and all things pertaining to a future, ▼ill bo equally prosperous, and glorious in its results.
GRAMMAR IN RHYME— For iiie Little Folks. — It is seldom that one sees so much valuable matter as th« following lines contain, comprised in so brief a space fivery young grammarian, and macy older heads, will find \t highly advantageous to commit tho " poem " to memory ;
Which reading, writing, speaking, teach.
MUSICAL CURIOSITY— Scotch Genius in TEACHrao.— A Highland piper, having a scholar to teach, disdained to crack his brains with the names of s'^raibreves, minims, crotchets and quavers. " Here, Donald," said he, " tak yer pipes, lad, and gie us a blast. So — wrra weel blawn, indeed ; but what's a sound, Donald, without sense ? Ye maun blaw forever without making a tune o't, if I dinna tell you how the queer things on the paper maun help you. You see that big fellow wi' a round, open face ? (pointing to a semibreve between two lines of a bar). He nioves slowly from that line to this, while ye beat ane wi' yer fist, and gie us a long blast. K, bow, ye put a le^ to him, ye mak' twa o' him, and he'll move twice as fast ; and if ye black his face, he'll run four times faster than the fellow wi' the white face; but if, after blacking his face, ye'll bend his knee or tie his le^ he'll hop eight times faster than the white-faced chap I showed you first. Now, whene'er ye blaw yer pipes, Donald, remember this — that the tighter those fellows' legs are tied, the faster they'll run, and the quicker they're sure to dance."
REMARKS. — It may be necessary to remark, and I do 1 ftere, once for all, that every article to be dyed, as well as everything used about dyeing, should be perfectly clean.
In the next place, the article to be dyed should be well fltoured m soap, and then the soap rinsed out. It is also an advaft^age to dip the article you wish to dye into warm water, ja* t before putting it into the alum or other preparar tioH ; for the neglect of this precaution it is nothing uneonamon to h<»ve the goods or yarn spotted. Soft water should always be used, if possible, and sufficient to cover the goods handsomely.
evenly.
Great confidence may be placed in these coloring recipes, as the author has had them revised by Mr. Storms, of this city, who has been in the business over thirty years.
COLORS ON WOOLEN GOODS.
1. CHROME BLACK— Superior to Any in Use.— For 5 lbs. of goods — blue vitriol 6 ozs. ; boil it a few minutes, then dip the goods J of an hour, airing often ; take out the good-s, and make a dye with logwood 8 lbs. ; boil J hour ; dip | of an hour and air the goods, and dip J of ao hour more. Wash iji strong suds.
oor fade by exposure to the sun.
2. BLACK ON WOOL— Fo Mixtures.— For 10 lbs. of wool -bi-chromate of potash 4 ozs. ; ground argal 3 ozs. j boil together and put in the wool ; stir well and let it remain in the dye 4 hours. Then take out the wool, rinse it slightly in clear water ; then make a new dye, into which
pt., and let the wool lie in all night. Wash in clear water
3. STEEL MIX— Dark— Black wool— it may be nat> ural or colored, 10 lbs. — white wool li lbs. Mix evenly t>* gether and it will be beautiful.
4. SNUFF BROWN— Dark, for Cloth or Wool — For 5 lbs. goods — camwood 1 lb. ; boil it 15 minutes, then dip the goods for J hour ; take out the goods, and add to the dye, fustic 2 J lbs.; boil 10 minutes, and dip the goods i hour ; then add blue vitriol 1 oz. ; copperas 4 ozs. ; dip again i hour ; if not dark enough, add more copperas. It is dark and permanent.
5. WINE COLOR.— For 5 lbs. goods— camwood 2 lbs. ; boil 15 minutes and dip the goods i hour ; boil again and dip J hour; then darken with blue vitriol IJ ozs.; if not dark enough, add copperas J oz.
6. MADDER RED.— To each lb. of goods— alum 6 ozs. ; red, or cream of tartar 1 oz. ; put in the goods and bring your kettle to a boil for i hour ; then air them and boi) i hour longer ; then empty your kettle and fill with clean water, put in bran 1 peck; make it milk warm and let it stand until the bran rises, then skim off the bran and put m madder J lb. ; -put in your goods and heat slowly untU it boils and is done. Wash in strong suds.
7. GREEN — On Wool or Silr, with Oak Bark. — Make a strong yellow dye of yellow oak and hickory bark, in equal quantities. Add the extract of indigo, or chemic, (which see,) 1 table-spoon at a time, until you get the shade of color desired. Or :
8. GREEN— With Fustic— For each lb. of goodsfustic 1 lb. ; with alum 3 J ozs. Steep until the strength ia cut, and soak the goods therein until a good yellow is obtained ; then remove the chips, and add extract of indigo or chemic, 1 table-spoon at a time, until the color suits.
9. BLUE— Quick Process. — For 2 lbs. of goods, — alum 5 ozs.; cream of tartar 3 ozs. ; boil the goods in this for 1 hour ; then throw the goods into warm water, which has more or less of the extract of indigo in it, according to the depth of color desired, and boil ugain until it suits, adding more of the blue if Doedod. It is quick and permanent.
to. STOCIKING YARN, OK- WOOL TO COLOR— Betwken a Blue and Purple. — For 5 lbs. of wool bichromate ol potash 1 oz. ; alum 2 ozs. ; dissolve them and briug tJie water to a boil, putting in the wool and boiling 1 hour J then tlirow away the dye and make another dye with litirwood chips 1 lb., or extract of logwood 2^ ozs., aud boii 1 hour. This also works very prettily on silk.
N B. — Whenever you make a dye with logwood chipf eitner boil the chips i hour aud pour off the dye, or tie u the chips in a bag and boil with the wool or other goods or take 2^ ozs. of the extract in place of 1 lb. of the chipt is \e:^ trouble and generally the better plan. In the abov reciptj the more logwood that is used the darker will be th shade '
11. oCARLET, WITH COCHINEAL— For Yarn ou Clotb. — For 1 lb. of goods — cream of tartar J oz. ; cochineal, well pulverized, i oz. ; muriate of tin 2 J ozs. ; then boil up die dye and enter the goods ; work them briskly for 10 or ib minutes, after which boil 1 i hours, stirring thu goods slowly while boiling, wash in clear water and dry in the shade.
12. PINK.— For 3 lbs. of goods— alum 3 ozs., boil and dip the goods 1 hour ; then add, to the dye, cream of tartar 4 ozs. , cochineal, well pulverized, 1 oz. j boil well and dip the goods while boiling, until the color suits.
13. ORANGE.— For 5 lbs. goods— muriate of tin 6 table-spoons ; argal 4 ozs. ; boil and dip 1 hour ; then add, to the dye, ttistic 2 J lbs. ; boil 10 minutes, and dip i hour, and add, again, to the dye, madder 1 tea-cup ; dip again J hour.
antil pleased. About 2 ozs.
14. LAC RED. — For 5 lbs. goods — argal 10 ozs. ; boil a few minutes ; then mix fine ground lac 1 lb. with muriate ot tin Ik lbs., and let them stand 2 or 3 hours; then add halt 01 the lac to the argal dye, and dip J hour ; then add the balance of the He and dip again 1 hour ; keep the dye at a boiling heat, 'v ' il the last half hour, when the dye may be cooled off.
15. PUKPLE.— For 5 lbs. goods—cream of tartai 4 ozs.; alum 6 ozs.j cochineal, well pulverized, 2 ozs. ; muriate of tin i tea-cup. Boil the cream of tartar, alum and tin, 15 minutes ; then put in the cochineal and boil 5 minutes ; dip the goods 2 hours ; then make a new dye with alum 4 ozs. ; Brazil wood 6 ozs.; logwood 14 ozs.; muriate of tin 1 tea-cup, with a little chemic; work again until j.leased.
16. SILVER DRAB— Light.— For 5 lbs. goods— alum 1 small tea-spoon, and logwood about the same amount ; boi] well together, then dip the goods 1 hour; if not dark enough, add in equal quantities alum and logwood, until suUed.
17. SLATE, ON WOOLEN OR COTTON— With Beach Bark. — Boil the bark in an iron kettle, skim out the chips after it has boiled sufficiently, and then add copperas to set the dye. If you wish it very dark add more copperas. This is excellent for stockings.
18. EXTRACT OF INDIGO OR CHEMIC— To Make. — For good chemic or extract of indigo, take oil of vitriol J lb., and stir into it indigo, finely ground, 2 ozs., continuing the stirring at first for i hour; now cover over, and stir 3 or 4 times daily for 2 or 3 days ; then put in a crumb of saleratus and stir it up, and if it foams, put in more and stir, and add as long as it foams; the saleratus neutralizes any excess of acid ; then put into a glass vessel and cork up tight. It improves by standing. Druggists keep this prepared.
19. WOOL— To Cleanse.— Make a liquid of water 3 parts and urine 1 part ; heat it as hot as you can bear the hand in it ; then put in the wool, a little at a timo, so as not to have it crowd ; let it remain in for 15 minutes ; take it out over a basket to drain ; then rinse in running water, and spread it out to dry ; thus proceed in the same liquor ) when it gets reduced fill it up, in the same proportions, keeping it at hand heat, all the time not using any soap.
20. DARK COLORS-To Extract and Insert Light, — This recipe is calculated for carpet rags. In the first place let the rags be washed clean — the black or brown rags oan be colored red, or purple, at the option of the dyer; to do
this, take, for every 5 lbs black or brown rags muriate of tin j lb.; and the lac ^ lb.; mixed with the same, as fot the lac red ; dip the goods in this dye 2 hours, boiling ^ of the time, if not red enough add more tin and lac. The goods can then be made a purple, by adding a little logwood ; be careful, and not get in but a very small handful, as more can be added if not enough. White rags make a beautiful ippearance in a carpet, by tying them in the skein and colring them red, green or purple ; gray rags will take a very ^i,ood green, — the coloring will be in proportion to the darkuess of mix.
DURABLE COLORS ON COTTON.
1. BLACK. — For 5 lbs. goods — sumac, wood and bark together, 3 lbs. ; boil J hour, and let the goods steep 12 hours ; then dip in lime water J hour ; then take out the goods and let them drip an hour ; now add to the sumac liquor, copperas 8 ozs., and dip another hour ; then run them through the tub of lime water again for 15 minutes • now make a new dye with logwood 2| lbs., by boiling 1$ hour, and dip again 3 hours ; now add bi-chromate of pot^ ash 2 ozs., to the logwood dye, and* dip 1 hour. Wash in clear cold water and dry in the shade. You may say this is doing too much. You cannot get a permanent black on cotton with Inss labor.
2. SKY BLUE.— For 3 lbs. goods— blue vitriol 4 ozs.j Doil a few minutes ; then dip the goods 3 hours, after which pass them through strong lime water. You can make thip color a beautiful brown by putting the goods through a solution of Prussiate of potash.
3. LIME WATER, AND STRONG LIME WATER.— Foe Coloring. — Lime water is made by putting stone lime 1 lb., and stroni? lime water, 1^ lbs. into a pail of water, slacking, stirring, and letting it stand until it becomes clear, then turn into a tub of water, in which dip the goods.
4. BLUE, ON COTTON OR LINEN— With Logwood In all cases, if new, they should be boiled in a strong soap suds or weak-lye and rinsed clean ; then for cotton 5 lbs. or linen 3 lbs., take bi-chromate of potash | lb. ; put in the goods and dip 2 hours, then take out, rinse j make a
wash out aud dry.
5. BLUE ON COTTON— WITHOUT Logwood.— t for 5 lbs. of rags — copperas 4 ozs. ; boil and dip 15 minutes j then dip in strong suds, and back to the dye 2 or 3 times; thco make a dye with prussiate of potash 1 oz.j oil of vit»iol i table-spoons j boil 30 minutes and rinse j then dr)*.
6. GREEN. — If the cotton is new, boil in weak-lye ox etrong .suds j then wash and dry ; give the cotton a dip in the home-made blue dye-tub until blue enough is obtained to make the green as dark as required, take out, dry, aud rinse the goods a little ; then make a dye with fustic J lb. ; logwood 3 ozs. to each lb. of goods, by boiling the dye 1 hour ; when cooled so as to bear the hand^ put in the cotton, move briskly a few minutes, and let lay in 1 hour; take out and let it thoroughly drain j dissolve and add to the dye, for each lb. of cotton, blue-vitriol J oz., and dip another hour ; wring out and let dry in the shade. By adding or diminishing the logwood and fustic, any shade of green may be obtained.
7. YELLOW. — For 5 lbs. of goods — sugar of lead 7 oz.s. ; dip the goods 2 hours j make a n-ew dye with bi-chromate of potash 4 ozs. ; dip until the color suits, wring out and dry, if not yellow enough repeat, the operation.
8. ORANGE.— For 5 lbs. goods — sugar of lead 4 ozs. ; boil a few minutes, and when a little cool put in the goods, dip 2 hours, wring out ; make a new dye with bi-chromatc of potash 8 ozs. ; madder 2 ozs. ; dip until it suits ; if the color should be too red, take off a small sample and dip it into lime water, when the choice can be taken of the sam pie dipped in the lime or the original color.
8. RED. — Take muriate of tin i of a tea-cup ; add sufiiicnt water to cover the goods well, bring it to a boiling i9eat, putting in the goods 1 hour, stirring often ; take out the goods aud empty the kettle and put in clean water, witn nic-wood 1 lb., steeping it for i hour, at hand heat ; theh put in the goods and increase the heat for 1 hear, not bringing to a boil at all ; air the goods and dip an hour as be lore ; wash without soap.
COLORING DEPARTMENT, 349
9. MURIATE OF TIN— Tin Liquor— If druggists ieep it, it is best to purchase of them already made ; but ii you prefer, proceed as follows :
Get at a tinner's shop, block tin ; -put it in a shovel and melt it. After it is melted, pour it from the hight of 4 or 5 feet into a pail of clear water. The object of this is to have the tin in small particles, so that the acid can dissolva it. Take it out of the water and dry it j then put it into a strong glass bottle ; pour over ii muriatic aeid 12 ozs. ; then slowly, add Bulphuric acid 8 ozs. The acid should be added about a table-spoon at a tiiac, at intervals of 5 or 8 minutes, for if you add it too rapidly you run the risk of breaking the bottle by lieat. After you have all the acid in, let the bottle stand until the ebullition subsides ; then stop it up with a bees-wax or glass stopper, and set it away, aud it will keep good for a year or more, or will be fit for use in 24 hours.
lb. of silk — yellow oak bark 8 ozs. ; boil it J hour ; turn off the liquor from the bark and add alum 6 ozs. j let stand until cold ; while this dye is being * made, color the goods in ehe blue dye-tub, a light blue ; dry and wash ; then dip in the alum and bark dyo ; if it doe-s not take well, warm the dye a little.
2. GREEN OR YELLOW— On Silk or Wool, in Five to Fifteen Minutes. — For 5 lbs. of goods — black oak bark or peach leaves J peck ; boil well ; then take out the bark or leaves, and add muriate of tin i tea-cup, stirring well ; then put in the goods and stir them round, and it will dye a deep yellow in from 5 to 15 minutes, according to thd strength of the bark ; take out the goods, rinse and dry immediately
N B. — For a green, add, to the above dye, extract of indigo, or chemic 1 table-spoon only, at a time, and work the goods 5 minutes, and air ; if not sufficiently dark use t.l«j same amount of chemic as before, and work again until it «uits.
hour ; wash out, and make a dye with Brazil wood 1 oi^ and logwood i oz. by boiling together ; dip in this i hour, then add more Brazil wood and logwood, in equal proportions, until the color is dark enough.
4. BLACK. — Make a weak dye as you would for black on woolens, work the goods in bi-chromate of potash, at a little below boiling heat, then dip in the logwood in the game way ; if colored in the blue vitriol dye, use about the same heat.
5. SPOTS — To Remove and Prevent when Coloring Black on Silk or Woolen. — N. B. In dyeing silk or woolen goods, if they should become rusty or spotted, all that is necessary is to make a wcak-lye, and have it scalding hot, and put your goods in for 15 minutes ; or throw some ashes into your dye, and run your goods in it 5 minutes, and they will come out a jet black, and an eveu color. I will warrant it. — Stoi'ms.
The reason that spots of brown, or rust, as it is generally called, appear on black cloths, is that these parts t'lke the jolor faster than the other parts ; but I have no doubt Mr. ^terms' plan will remove them, for he regretted much to make public the information, which he says is not generally known. And if the precaution, given in our leading remarks on coloring, are heeded, there will be but very little danger of spotting at all.
6. LIGHT C HEMIC BLUE.— For cold water 1 gal., dissolve alum i table-spoon, in hot water 1 tea-cup, and add to it ; then add chemic 1 tea-spoon at a time, to obtain the desired color, — the more chemic that is used, the darker will be the color.
7 PURPLE.— For 1 lb. of silk— haviag first obtained a light blue by dipping in the home-made blue dye-tub. aad dried, dip in alum 4 ozs., to sufficient water to cover, whea a little warm ; if the color is not full enough add a little chemic.
6. YELLOW.— Fori lb. of silk— alum 3 ozs.; sugar ot lead I ozs ; immerse the goods in the solution over night j take out, drain, and make a new dye with fustic 1 lb. j dip until the required color is obtained.
and repeat as desired.
10. CRIMSON.— For 1 lb. of silk— alum 3 ozs. ; dip at hand-heat 1 hour ; take out and drain, while making a ne\v dye, by boiling 10 minutes, cochineal- 3 ozs. ; bruised nutgalls 2 ozs. ; and cream of tartar i oz., in one pail of water j when a little cool, begin to d'.p, raising the heat to a boil continuing to dip 1 hour; wash and dry.
11. CINNAMON OR BROWN ON COTTON AND SILK. — By a New Process — Very Beautiful. — Give the goods as much color, from a solution of blue vitriol 2 ozs., to water 1 gallon, as it will take up in dipping 15 minutes; then run it through lime-water; this will m:ike a beautiful sky-blue, of much durability ; it has now to be run through a solution of Prussiate of potash 1 oz., to water 1 gal.
DIFFERENT STATES J AlSO, SHOWING WHAT KATES MAY
be contracted for, and collected j and giving thk Forfeitures when Illegal rates are Attempted to BE collected. — First, then Six percent is the Legal rate in the States of Maine, New Hampshire, Rhode Island, Connecticut, Vermont, Delaware, Maryland, Pennsylvania, Virginia, North Carolina, Florida, (^Eight per cent, is allowed in this State if agreed upon), Mississippi, Tennessee, Arkansas, Kentucky, Ohio, Indiana, Illinois, Missouri, Iowa, and New Jersey, excepting, in Hudson and Essex Counties, and the city of Patterson, in this last State, Seven per cent is allowed, when either of the parties reside therein.
Georgia.
Third ; Ten per cent, is the Legal rate in California ; Eight per cent, in Alabama and Texas, and as strange as it may appear, in Louisiana only Five per cent.
Maine and Vermont allow'no higher than iegal interest to be collected, even if agreed upon. And if paid it caa bo recovered again, but no forfeiture.
to be collected, even on usurious contracts.
In Connecticut, if usurious contracts are made, the principle only can be collected, to the lender, or, if collected, can be recovered, one-half to the informer, the other half to the State Treasuiy.
In Mississippi, although ^Ix per cent, is the legal interest ou common debts, yet for money, actually borrowed, eff/ht per cent is allowed, and although a rate may be agreed upon above what the law allows, simple interest may still be collected.
Louisiana, although allowing only^tc per cent, where no stipulation is made, permits gi'yht per cent, in agreement, and Bank interest to be si'j. per cent.
In Texas, although ei(//it per cent, only is the legal rate, yet twelve may be contracted for, but if higher rates an agreed upon, none can be collected.
and only lawful rates can be collected.
In Missouri, ten per cent, may be contracted for, but forfoite ten per cent, to the common school fund, in cases where more than lawful rates are obtained.
Wisconsin formerly permitted twelve per cent to be ^reed upon, and those who paid more than lawful rates might recover back three times the amount paid ; but more recently allows only *ew per cent., and makes all above that amount utvriovs.
collectefl .
The interest which the State allows to be collected on n^tes drawn, " with use," not specifying the rate, is called lepal, and that which some States allow to be contracted for, above the legal rate is lawful; but when a larger rate is taken, or •greed upon, it is called usurious^ and subjects the person agreeing for it, or receiving it, to l\iQ penalties^ or forfeU*'-reSy as giveu in the foregoing explanations.
Any Agent, or other person, who may know of any changes in their States from these rules, will confw a itff^t cm the Author by communicating the same.
months, and 27 days, at 6 per cent.
Turning to the tables you will see that the time is given in the left-hand column, the amounts on which you desire to find the interest are given at the heads of the various right-hand columns, the sum sought is found at the meeting of the lines to the right of the time, and down from the amount, aa folio fv a :
In the same manner, proceed with any other amounts, or any other time, or rate per cent, j and if for more than one year, multiply the interest for \ year by the number of years for whi^h the interest is sought; if for twenty, thirty, sixty, or aay other amount between ten and one hundred dollars, multiply the interest on ten dollars, by the number of tens iu the amount, which gives you the whole sum of interest sought ; the same rule holds good on hundreds, betweea one hundred and one thousand, and also, on thousands.
Again, for persons in advanced life, say from 60 years, the dose must begin to lessen about 5 grains, and from that on, 5 grains for each additional 10 years. Females, however, need a little less, generally than males. The above rules hold good in all medicines, except castof oil, the proportion of which cannot be reduced so much, and opium, and its various preparations, which mutt bt reduced generally, in a little greater proportion.
ecarles liVeights and Measures.
One pound (lb.) contains 12 ounces. One ounce (oz.) " 8 drachms. f One drachm (dr.) " 3 scruples.
One table-spoon " about half a fluid ounce. One tea-spoon " " one fluid drachm. Sixty drops make about one tea-spoon.
Whenever a tea, or table-spoon is mentioned, it means the same as it would to say spoonful ; the same of cup, in fluid measures ; but in dry measures, where a spoon, or spoonful is mentioned, the design is that the spoon should be taken up moderately rounding, unless otherwise mentioced.
Aqua. .Water.
Aqua Ammonia . . Water of Ammonia. Amenorrhea. .Absence of the menses. Antiemetie. .That which will btop vomiting; against emesis. Arseni6..A metal, the oxide of which is arsenioua acid,
Belladonna . . Nightshade.
Bergamx)t. .Perfume made from the lemon peel. Bile. .A secretion from the liver. Bilious. .An undue amount of bile. Bi-tartrate of Potash . . Cream of tartar. Blanch. .To whiten.
Catarrh. .Flow of mucus.
Cathartic. . An active purgative. Caihtter . . Tube for emptying the bladder. Carminative. .An aromatic medicioe. Caustic. .A corroding or destroying substance, as nitrate of
draughts to the feet, ke.
Congestion. .Accumulation of blood in a part, unduly. ConvalescPTire . . rmprovement in health. Cuticle. .The outer or first por-.Jon of the skin, which consists of three coat,«. Datura Stramonium . .Stink-w-ccd, jimpson, &c. Diaphoretics. .Medicines which aid or produce perspiration* Decoction. .To prepare by boiling. Dentrifice. .A preparation to cleanse the teeth. Defecation . . To pass the feces, to go to stool. Dentition . . Act or process of cutting teeth. Desiccation . .To dry, act of drying. Denudcent. .Mucilaginous, as flax-seed and gum arabio. Dermoid. .Resembling, or relating to the skin. Z^efen/cn^s. .Cleansing medicines, as laxatives and purgft*
Eclattic . . To choose.
Eclectic Physician. .Oac who professes to be liberal Ia views, independent of party, and who fa-or progress and reform in medicine.
Effete. .Worn out, waste matter.
Elaterium. .Fruit of the wild cucumber, a hydragogue. Electuary — Medicine prepared at the consistence of honey. Elixir. .A tincture prepared with more than one articlo. Emesis . . The .act of vomiting. Emetic . . Medicines which produce emesis, vomiting. Ehnnienagogue . .A medicine which will aid or bring on the menses.
Emulsion . . Mucilage, from the emolients. Enema. . An injection by the rectum. f^nnui. . Lassitude, dullness of spirit, disgustof condition, &o. Epi. . Above, or over.
Eschar' — A slough on the surface. Efcharotic . . That which will destroy the flesh. Essential. . Having reference to essences made from essen
tiveness.
Evaporcxdon . . To escape in vapor. Exacerbation. .Violent in'^rease in disease. Exanthemata . . Eruptive disease, as small-pox, scarlet fever,
Excrement . . The feces, that which passes by stool. Excretion . . That which is thrown off", become useless. Excoriation . . Abrasion, to bruise the skin. Exhalents. .Vessels which throw out fluid upon the external or internal surface of the body. Eepectorants . .That wliich produces, or aids a discharge of
Ferrum. .Iron.
Fever. .That which "Old School Physician.s" call a diseade, whilst another cla.s3 (the Thomsonians) say it is an eflFort of nature to throw off disea.se ; but Eclectics take it as an indication that the circulating medium is not regular, and go to work at once to eqiulize the circulation, by the use of diaphoretics, combined with tonics and detergents, which soon sets all to-rights ; for fever and perspiration cannot long exist together.
Flooding. .Vtcrme hcmoiThage.
Fluor. .An increaised discharge, to flow Fluor Sjjar. .Fluoride of calcium. Fluor Albus . . White flow, leucoiihea, whites, &c. Flvtx . . To flow, diarrhea.
Fusion . . To fuse, to melt.
Furor. .Very violent delirium, not accompanied by fever. Galhanum . . A resinous gum, from a genus of plants. Genus. .Family of plants, a group, all of a class, or nature. GaU..B\\e.
muuis.
Galla. .The gall-nut, an excrescence found upon the oak. Gallic Acid. .An acid from the nut-gall. Galipot. . A glazed jar, used for putting up gummy extracta. Galcanv;. .Having reference to galvanism. Gamboge. .A drastia purgative, unless combined with aro-
Gestation. .To be pregnant.
Gland. .Secreting organs having ducts emptying into cavities, which often become obstructed, causing them to enlarge ; hence, the enlargement of the thyroid gland in the neck, causing bronchoceie.
Gravd. .Crystaline particles in the urine. Green- Sickness . .Chlorosis, debility requiring iron. Griping. .Grinding pain in the stomach, or bowels. Gutta . . One drop, drops.
place.
Habit. .Good or bad habit, constitutionally, or prejudicially predisposed to do some particular thing ; medically, as consumptive habit, rheumatic habit, &o,
Hypo. .Signifies low, a low state of health, more annoying to the sufferers than to their friends, who are constaatly boring them about it ; called hysterica .n women, (from hysteria, the womb or uterus,) but blues only, when it gets hold of men; they come from the same cause, general debility • takes a strong remedy, iron, as medicine
r»i/iVmrtry. .Where medicines are distributed gratuitously to the poor ; but more recently some physicians have got to calling their offices infirmaries
Intermittent Fever. .Fever which comes on at regular periods, between which periods there is little, and sometimes no fever, an interval.
intestines. .The contents of the abdomen.
Intestinal Ctnia/. .Embracing the duodenum (the first di vision below the stomach,) the jejunum, (the the second division of the small intestines,) the ileum, (the third and longest portion of the small intestines,) the secum, (the first portion of the large intestine,) the colon, (the large intestine,) and the rectum, (the lower trap-door.)
Jesuits Bark. . First name ef Peruvian bark, from its having
been discover<nl bv Jesuit missionaries. Juglar. .Applied to veins of the th-roat. Jujube.. An East India fruit, something like a plun, lUtid
Labia . . Lips.
Italia Pudendi. .Lips, or sides of the vulva. Labial. .Of, or belonging to the lips. Labor. .Child-birth; parturition.
Lotion . . A preparation to wash a sore.
Lubricate. .To soften with oil, or to moisten with a fluid. The internal organs are covered with a membrane which throws out a lubricating fluid, enabling them to move easily upon each other.
case, as the Cholera of 1882.
Mamma . .Tlie female breast, which is compoecd of glands that secrete the milk, upon the principle that the liver secretes bile ; each organ for its specilio purpose; but secreting organs, or glauda are the more liable to get obstructed, thus pro ducing disea.se.
Maslurbation. .Excitement, by the hand, of the genital organs. The most injurious, health-destroying, soul-debjising, ol all evils introduced into th« world; because lU frequent repetition draw^ very heavily upoL \he nervous system, prostrating the energies, acstroying the memory, together with the lii'i-principle, as well as th» principles of muialitN which ought to goveru every human bciug, .letween himself and hia Cieator.
Medicated. .Having mediciao in its piCparation.
Membrane. .A thin lining, or coveiing, skin-like, as the poritoueuHi, whie-h lines ihb cavity of the bowels and covers the intestinoa; and tho periosteum, membrane, which concm the bones, &e
Organism. .Vital organization.
Organized. .Furnished with life. Orgcum. .The closing excitement of fsexual coBoeotioBi Origin. .The point of commencement. Orifice. .An opening.
ULOSSAJRIAL DEPARTMENT. 879
(hraria. .Testes; most generally applied to the female ; fomale testes, two egg-shaped bodies, (made up of little particles, or eggs,) having an attachment to the uterus in the broad ligaments, which support that organ, having tubes, oi ducts, opening from them into the uterus, called Fallopian tubes, from the man's name who first gave a description of them. One of these particles is thrown off at each menstrual flow.
gCftiifm.
Pfptie. .Digestive; hence, dyspeptic, not digesting. Percolation. .To run, or dmw through some substance, straining Premonitory.. 1o give a previous notice, as premonitory S3'mp
Ptru, .Around, a covering.
Pericardium. .Around the heart, sac containing the heart. Pericarditvi. .Inflammation of the pericardium. Perin..A testicle, male organs, con-esponding with testes, in
Period. .A certain time.
PeritHliciiy . .Returning at a certain time. Periosteum. .The membrane which covers all bones. Per^pccti'ce View. .As it appears to the eye at a certain distance J'erturbation . . To disturb.
natural course.
Pesmry. .That which will support, or hold up the womb, in prolapsus ; see our remarks on " Female Debility." Phagedenic. .An eating and fast-spreading ulcer. PhaiiTuiey. .The art ol combining and preparing medicines. Phlegm. .Mucus from the bronchial tubes, and throat. Phlogistic. .Tendency to inflammation. Phosphoi-us . .An iutlammable and luminous substance, prepared
Pulvis. .A powder ; hence, pulverize, to make fine. All thes^ words show how heavily we have drawn upon other languages, for our own, consequently, the necessity of studying the Latin and Greek, to properly understand ours.
Pyroligncoun Acid. .An acid obtained from wood; the essence of smoke ; if a little of it is put into a barrel with meat in the brine, it smokes it without trouble. I think
§ill to the barrel sufficient, perhaps a little less will o. It is obtained by inserting an old gun-barrel or other iron tube into a coal-pit, near the bottom, whgg burning; it condenses in the tube and drops from w outer end into a di.sh, then bottled for use. Quama. .A bitter Ionic ; the chips of the wood are used. Machis..Th&imi*
JtacJiitis. .Rickets, bending of the spine, and sometimes the long bones of the limbs ; may be also enlargement of th« head, bowels, and the ends of the long bones
be reduced.
Sudor. .Sweat; hence, sudorific, to sweat. Sulphate. .A combination with sulphuric acid. Sulphuric Acid. .Oil of vitriol. Suppr6»sion. .An arrest of a natural discharge. S>cppuration . . To produce ])U3. SympaOiy. .To be afl"eeted by the disease of another orgaa, u
Tannic Acid. .An acid from oak bark, an astringent. Tartaric Acid. .An achl from cream of tartar, found in grapes. Temsmus. .Difficulty and pain at stool, with a desire to go to
Zinci Sulphas. .Sulphate of Zinc, white vitriol.
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XGYMaXEN-mewxuvI | Hymns and Spiritual Songs | S. T. Francis
I AM waiting for the dawning
Of the bright and blessed day,
When the darksome night of sorrow
Shall have vanished far away:
When, forever with the Saviour,
Far beyond this vale of tears,
I shall swell the song of worship
Through the everlasting years.
2
I am looking at the brightness
See, it shineth from afar;
Of the clear and joyous beaming
Of the bright and morning Star.
Through the dark grey mist of morning
Do I see its glorious light;
Then away with every shadow
Of this sad and weary night.
3
I am waiting for the coming
Of the Lord who died for me;
Oh, His words have thrilled my spirit,
“I will come again for thee.”
I can almost hear His footfall,
On the threshold of the door,
And my heart, my heart is longing
To be with Him evermore. | 191 | common-pile/pressbooks_filtered | https://pressbooks.pub/hymnbook/chapter/i-am-waiting-for-the-dawning/ | pressbooks | pressbooks-0000.json.gz:96433 | https://pressbooks.pub/hymnbook/chapter/i-am-waiting-for-the-dawning/ |
ocGWiF0cR91hpM9Z | The hoot of the owl, by H.H. Behr. | IRISH HISTORY . . . . .
WORSHIPFUL SIRE: I stand here as the representative of the German Pfeifen Club, and have to correct a slight error that introduced itself into the address delivered by your Worship. It is not to announce the subjugation of the Pfeifen Club that I appear before you. I am not a hostage; I am an ambassador of a kindred organization. The object of our institutions is the same; our organizations follow a parallel course. The object of both is charity. Not that charity which sends ice-cream to the Greenlanders and skates to the people on the sources of old Nile; no, true charity begins at home. And where are we more at home than inside our own stomachs?
10 THE HOOT OF THE OWL.
It is, therefore, a most wonderful coincidence that both organizations, the Bohemian as well as the Pfeifen Club, struck the same idea of international charity. Both found the solution of the social question in an alcoholic solution.
The solution tendered to me by your Worship smells very nice, and I pledge myself in it to my Bohemian friends.
my unworthy mouth:
"My Sons : I am pleased to see the veneration that you have shown to me on so many occasions. Since the day that my patron, Minerva, was born out of the head of Jupiter, which circumstance forever will be the only case of cerebral pregnancy, I always had a longing for mental enjoyment, and I thank you, my sons, for all the exercises in art, literature, pedro, seven-up, and other sciences which I have witnessed in the old club-rooms. I also thank you for all the rats, mice, seagulls, neck-pieces of beef,
and all the other delicacies of which, on my behalf, you have deprived yourselves so unselfishly. I also thank you for the good taste you have shown in choosing the nocturnal hours for your celebrations, for I hate matinees. I am a bird of prey of the sub-family Nocturna, that differ from the vultures by the strength of their claws, from the eagles and hawks by the comparative weakness of their bills. But if my bill is weak, I nevertheless respect large bills and admire the courage that meets them. Owing to the weakness of my bill, I am a bird of few words; as the immortal poet Bromley sings:
u c There was an owl that lived in an oak, The more he heard the less he spoke, The less he spoke the more he heard. Oh, let us be like this wise bird/
" But I keep my watchful eye on you every night; in daytime better look out for yourselves. Like a Haruspex of old, I have examined with prophetic eye all the neckbones of beef which you have sacrificed to
success and progress.
" Being a bird of prey, I have prayed for you all the time, and I will do so now in the words of Sanctus Cremonius: 'May the Lord love you and not call for you too
VIRTUE.
SOCRATES used to say that everybody was eloquent enough on those matters which he understood thoroughly. Now, that's exactly my case in regard to virtue. There is no object in this wide world with which I am so intimately connected as with virtue. " Be virtuous and you will be happy." You have all frequently listened to this admonition, but I suspect there are very few among those present that have subjected this axiom to a practical trial. I have, and I am here to give you the benefit of my experience.
In my peculiar case, the admonition to be virtuous and happy came from an aunt of mine. But as this contemplation will occupy several hours, I consider it proper to divide the matter and look at the subject of
myself.
My aunt was an elderly lady, not exactly prepossessing in her exterior, but shockingly virtuous and as unmarried as possible. Her favorite beverage was tea of valerian with a stick in it of sulphuric ether. She wore green spectacles, always felt miserable and respectable, and between asafoetida and valerian led a most unhappy life. Her only occupation was virtue. In her leisure hours she made a most interesting collection of medicine-bottles and pill-boxes, of all shapes and sizes. So she used to sit near the peaceful slope of her favorite pill-box, looking through her green spectacles at humanity as it passed her window, and talked virtue and gossip. It took considerable time before I could separate the idea of virtue from
that of green glasses, or distinguish the odor of sanctity and the smell of a drug-store; but when I finally succeeded in doing so, I made up my mind to give virtue a fair shake.
Gentlemen, I have practiced several virtues,— moderately, of course, for I always was of temperate habits, — but somehow or other during the whole time of my experiments I felt dejected and miserable, and the happiest moment of my life was when I dropped virtue altogether.
Virtue is a swindle. I have seen people ruined by one single virtue. How would they have fared then had they possessed two, three, or more. On the other hand, I have a friend, a dear friend, who is in possession of a complete and well-arranged collection of all those vices that possibly can be practiced in this sublunary world, and he is happy, he is successful, he is at peace with himself and with the whole world. It is true I know there are instances where people have been ruined by vice; but in such
cases you will observe they always have been ruined by one vice, never by several at the same time ; and so it is evident that they were not ruined by that one vice, but by the absence of all others.
Alas! vice is no more what it was when I was young. Vice is growing monotonous; there is not enough variety in it, and it is a most melancholy fact that since Sir Walter Raleigh introduced tobacco no new vice has been invented. The inventor of a new one would be a benefactor to humanity. Now, here is an object worthy of the accumulated energies of the Bohemian congregation.
ARCHEOLOGY.
WHEN I received the order of our most gracious Sire to appear before him at the Christmas High Jinks and report on the progress made in the Archaeological Section of the organization, I began immediately my investigations by borrowing books from all libraries that had not yet had any sad experiences in my direction. The message of our most gracious Sire met me at 5 P. M., at the exact moment when my thirst for knowledge transforms itself into a thirst for something else, and I felt highly honored, but at the same time at a loss how to respond to a confidence placed in me on such an important and serious matter.
Modern history of the Bohemian Club is comparatively well known. The celebrated historians, Tommy Newcomb and
Colonel Cremony, the Baron Miinchhausen of the western hemisphere, have preserved for posterity the events which led to the formation of the present shape of this learned and moral organization. To be better understood, when I have to dive into the dark mysteries of post-tertiary times and previous geological periods, I am to repeat here the statements of Tommy and his friend Colonel Cremony, both of them such enthusiastic lovers of truth that they kept all of it to themselves.
You will recollect that the organization of this ancient order had originally the object to protect the genius of the reporter against the want of appreciation by an unenlightened public, as well as the narrowminded and merely mercenary views of the newspaper-owners. Originally of a strictly literary character, the club soon extended its welcome to sculptors and painters, because they strive in the same line — they represent things which are no realities, exactly as our newspapers palm off novelties which
are no facts and facts which are no novelties. Then the welcome was extended for exactly the same reason to lawyers and later to musicians, as the transitory character of their productions cannot inflict any serious harm. Finally some Front-Street millionaires obtained admission by carefully concealing the real amount of their fortunes.
It is a well-established historical fact that the Spartan hero Leonidas, by George Bromley persistently mistaken for General Barnes, was a prominent member of the organization. Less known it is that the greatest physician of antiquity — Hippocrates— belonged to it. The order always had a great power of attraction for medical men. It was during the last years of the reign of Philip of Macedonia, when the medical profession was suffering from an intensely healthy year; in fact, it was an epidemic of health. The professors of the Polyclinics of Stagira were suffering from starvation. They had grown so thin and
diminished in circumference that they could no more fill their chairs. Hippocrates awoke to the emergency. He saw it was impossible to reproduce the necessary rotundity to fill a medical chair by mere demonstrations a posteriori, so he started a new medical system, chiefly founded on fees, and therefore called the physiological system. He laid great stress on physiology, and wound up every lecture with the admonition, "Be very particular about fees"; and then he grew excited, stamped his feet, and swore an oath, which ever since has been called "the Hippocratic oath," and which each of the medical fraternity, even our most gracious Sire, has been compelled to swear. This oath gives us power over the life and death of our fellow-citizens.
It was towards the end of the Lias formation when the citizens of San Francisco handed in a petition to the Legislature, meeting just then at Sacramento, for a volcano. They argued that if an effete monarchy like Italy can raise two volcanoes,
this free community of loyal, hard-drinking taxpayers is at least entitled to one. Blackstone, who was then a member of the Legislature, said the point was well taken. A committee was appointed, an appropriation raised, and Telegraph Hill selected as a center for the newly created forces. Unfortunately, the head engineer, who very appropriately had been selected from amongst the most practical sailors of the Life-Saving Station, had economized with the material so that locally he only produced an eruption of the skin; but the miscalculated forces caused the Second-Street cut and a long series of earthquakes, which interfered greatly with the stability of the California coast line. It is not quite certain whether it was Divine Providence or our Board of Supervisors that restored the stability of our coast line by placing the powerful Captain Kenzel on it, whose soothing influence quieted the disturbed nervous system of Mother Earth and kept it in its position ever since. However, the
powerful Captain would not have succeeded if he had not found assistance in a Board of Health whose weight and physical proportions had grown to an extent that they spoiled a North-Pole expedition, none of the scientific staff of the expedition being able to pass through the Behring Straits.
The disturbance of the post-tertiary era finally was kept down by our Geological Survey; a few ice-cream saloons on Kearny Street being the only remainder of the glacial period; but revolutionary tendencies crept into society because society had witnessed so many violent geological disturbances and was infected by the bad example set by Nature herself. This circumstance was the cause that the powers of our public officers had to be extended, and was the first step to the development of the present despotic government of the Bohemian Club, which, although benevolent, is very powerful.
of honor once before; so he is not only his own successor, but also his own ancestor. By this circumstance he becomes a selfmade man, and as such is the first instance of a self-made man in the ancient dynasty that rules the Bohemian Club.
POPULAR SCIENCE.
IT is one of the greatest blessings of this century that science has become popularized. In bygone ages science was the monopoly of a caste. The most important discoveries were kept secret, and, as a natural consequence of such egotism, the progress of the human race was retarded. Champollion, the celebrated scholar of Egyptian antiquity, has established beyond any doubt the fact that the ancient Egyptians knew the corkscrew. The hieroglyphic sign heretofore believed to represent a snake is in fact the hieratic representation of a corkscrew slightly out of shape. But the discovery of this important instrument was never made publicly known, notwithstanding the extensive use
mysteries.
When the Caliph Omar, who was a fanatical W. C. T. U. man, destroyed the library of Alexandria with all its spiritual treasures, the key to all the spiritual comfort was lost with them. Centuries have gone by and a great amount of valuable time has been lost in the effort to open bottles unscientifically by mere brute force. The great Euclides, when studying the qualities of the spiral line, did not strike the idea of the corkscrew, and it was not until the time that French enterprise perforated the Isthmus of Suez that the corkscrew of the ancients was rediscovered. There they found the venerable antiquity at a depth of two hundred and seventy-five feet below the bottom of the Red Sea, in a shaft perforating the metamorphic formations of the surface, on a stratum of brown cake laterally compressed and evidently of volcanic origin.
To MOSES,
City and County Assessor of Egypt. Dear Baron: — We, Pharaoh I, by the grace of God, King of Egypt, send you this decoration as a Christmas-box and a token of our Royal Grace.
in the year before Our Lord 1500.
From this moment began a new era in the history of man. Discovery followed discovery. Steam-power, the telegraph, the telephone, and the great Dr. Pinchipinchi's celebrated flea-powder were discovered in rapid succession, and are at present the inalienable property of the human race. For all these benefits, of course, we are indebted to our learned organizations, the Microscopic Society, Bohemian Club, Academy of Sciences, the Society to Promote Cruelty of Insects to Man, but at the same time to public lecturers, like Artemus Ward, who expound science to the many and combine
New disciplines of science will crop out of such combinations. We have already now forensic medicine, the compound of medicine and law, but we will soon have surgical music, obstetrical aesthetics, gynaecological astronomy, and other new disciplines which will prove a benefit to the human race and consternation to the schoolma'ams. But the consternation of schoolma'ams is not the sole object of modern science, whose concentrated spirit can be absorbed only by the chosen few; science has to be diluted and sweetened by music in the same fair proportions as other mixed drinks, and is then called "science toddy."
PROGRESS IN SCIENCE.
I AM sorry, but I am unprepared. Fortunately, I have in my pocket a paper which I intended to read before our Academy of Sciences. As the evening is rather advanced, perhaps you will be kind enough not to know the difference.
The paper is on the progress that has been made last year in the sciences. The progress of unprofitable science and useless investigation has been unusually rapid, so that it is impossible to enumerate all the benefits which the human race has received by the untiring efforts of devoted scientists.
Let us begin with the heavens — Astronomy. A great astronomer has discovered in the rings of Saturn an inscription which in a careful translation reads: "Commit no nuisance"; from which inscription the
learned professor justly concludes that the population of the remote region has arrived at a state of civilization analogous to our own.
In zoology the distinguishing characteristics between the green turtle, the mock turtle, and the mocking-bird have been so well established that henceforth the mistake of putting a green turtle in a cage and expecting him to sing will not happen any more.
In regard to eulogies and necrologies for dead scientists, a marked improvement has been established. These eulogies are nowadays written during the lifetime of the dead scientist and the composition is superintended by himself. This circumstance will serve as another proof of the immortality of the soul, because the most confirmed infidel will say to himself: "If that fellow is made immortal during his lifetime, why shall I not be so after my death?"
that the real utility of lectures on moral philosophy has been established. It is my own discovery that lectures of this kind produce water; of course, not of a superior quality, but good enough for irrigation. Vegetation in its perverted taste and fanatical rejection of fermented liquors does not deserve any better fluid; and so, my dear brethren, let us be thankful that we, according to our principle of strict intemperance, do not depend on irrigation by moral philosophy.
MUSIC.
WE have been touched frequently to our very hearts in these rooms by the musical performances of our musical brethren. Frequently, roused by the strains of music, the tears have rushed to our eyes. Do you think that heaven, which is so far above, is less sensitive to the charm than we poor mortals? Of course, the quiet quartet of the amateurs or the soprano in the boudoir cannot much influence our California sky. This influence begins with the solitary flute accompanying the heartrending wails of a rat terrier addressing the moon; it gains power with the performance of the wild Italian organgrinder, and attains its maximum with the brass band that leads the bold militia warrior to glory and the destruction of sandwiches and whisky.
I recollect a body of heroes wearing rainbows instead of regimentals and having painted on their knapsacks the head of a tiger in an attitude as if his teeth were inspected by a dentist. By the first notes of their brass band the azure of our California sky turned into a delicate apple-green, and it began to rain. Half an hour later we received a telegram that Sacramento was under water. Another deluge — and the destruction of the world — was prevented by stopping the music.
You may call that a coincidence, but in this wide world there is not room for a single coincidence ; everything is immutable law, the whole universe a network of cause and effect. You may sing and say we met by chance, but in reality we did not meet by chance, but compelled by the Darwinian law of natural selection. The spheroid shape of this planet is the cause that we wear off our boots on one side, by frequently walking too much in one direction. Why are the days longer in summer than in
winter? It is the consequence of the caloric law; they are expanded by the heat in summer and contracted by the cold in winter.
I had a friend, a dear friend in Australia, who never could go shooting without being caught in a thunderstorm. The Australian Legislature, ever attentive to the agricultural interests of the country, appointed him Inspector of Thunderstorms. Five months afterwards he was killed by lightning. Why have we not a similar institution? It would be a blessing for this country if every five months a legislator was killed by lightning, like that old Roman king and legislator, Numa Pompilius, who must not be mistaken for Paul Neumann, whom I have known as a legislator, but who is no king, and, I am happy to say, is not yet killed by lightning.
CALIFORNIA.
I DIVIDE the existence of California into two periods: the first, before the foundation of the Bohemian Club, has to be considered as prehistoric. Even this period is distinguished by a very peculiar character, gradually changing to three different stages or grades, which I am to illustrate by three different experiences.
I was but a few days in San Francisco when a rough-looking individual — a Texas Ranger, as I afterwards heard — laid his hand on my shoulder, with the words, " Old horse, take a drink?" I had presence of mind enough to take the drink, and had afterwards several opportunities to get even with the gentleman in taking drinks as well as in calling him "old horse."
when the Territory of California was admitted as a State. A procession was formed, in which I participated at the side of a gentleman to whom I was not introduced. Silently we walked on, influenced and absorbed by the significance of the historical moment, when my companion abruptly remarked: "It's a long time that I have not seen you." I was astonished and answered : "I never saw you all my lifetime." "And is not that long enough?" retorted my companion in the most mellifluous accents of green Erin. That day we got very much acquainted.
The third experience was in the rooms of the Vigilance Committee, where we discussed the case of Mr. Stuart. The meeting was addressed by Jim Dows, and I recollect distinctly the words : "Gentlemen, to hang a man is a temporary and transitory matter, but the principles which we represent here are eternal."
citizen and fervent admirer of Squibob, whose untimely end I have regretted for years, until, being introduced into the Bohemian Club by Mr. Bowman and Tommy Newcomb, I discovered the place where Squibob's ghost is still walking.
My Bohemian friends, the fight for existence has not always been to me an easy matter. We all have had times when care for material things overpowered us, when we became disgusted by unprovoked jealousies. When those cares of the outer material world became discouraging I withdrew to ideal Bohemia. But Bohemia was not only to me an asylum against material cares ; it was also a shrine consecrated to literature, from where new vistas opened into the realms of the bold, original American humor, so well represented inside these walls, and outside by men like Mark Twain, Bill Nye, and many others of world-wide fame. I received here new conceptions of many things; and if I count a few triumphs in literature, I owe them to Bohemian conver-
THE SKELETON IN ARMOR.
I ALWAYS was touched to my very heart by the beautiful lines written by Longfellow on " The Skeleton in Armor." I felt a burning desire to know more about the skeleton. I began to study the Iceland Eddas, the Saemundur, and the Snorri Sturleson Edda, the most ancient numbers of the Jolly Giant, and other reliable documents of history. In the course of this reading I succeeded in diverting the subject from all romance and establishing the following historical facts.
Many thousand years ago, when the giant elk was not fossil, but trod in flesh and blood the mossy bogs of ancient Ireland, when the mastodon and the rhinoceros tichorrhinus roamed through the majestic primeval forests of sauerkraut that then
covered all northern Europe, there, on a beautiful site, embellished by a meridian cutting the coast line of the Baltic, lived a pious knight named Hans Meyer. Like all the knights of the period, Hans Meyer was in love, and, according to the enthusiastic custom of the country, killed off all the dear relations of his lady love.
The Baltic hero grew restless. He wanted to travel far away from his home into distant climes where there were no mothers-in-law. He wanted to emigrate and settle in the East Indies, where a wise law ordered widows to be burned, and decimated in this judicious way the contingent of elderly ladies. The simple-minded but thoughtful hero foresaw that he might go around the Cape of Good Hope, or cross the Isthmus of Suez with the India mail. Either way he would most necessarily want funds. To obtain them, he imitated the
signatures of wealthy fellow-citizens. But as this style of calligraphics was not considered lawful, he was sentenced to prison for life; that is, according to the rules of the mild patriarchal government of the region, he was allowed for several months inside of a penitentiary, to study the charmingly adapted architecture of the place, and then was put on board of a vessel bound for America, under the conditions never to return and to adopt the name of Pilgrim Father.
It was then the custom that no foreigner whatever was admitted on American soil without his accepting an office. No sooner heard the first of the Mohicans, who was then the President of the United States, of the arrival of another cargo of distinguished foreigners, than he asked the favor of a private interview with Hans Meyer. Hans Meyer found the first of the Mohicans busily employed smoking his calumet filled with Amiga s prim era calidad, calle de Obispo.
"Hans Meyer," said the first of the Mohicans, "glad to make your acquaintance. You see, this government is a philanthropic experiment. We want to make everybody fit to fill every office, and for that reason we appoint for each office the man who is least adapted, for his mind and capacities are most in need of being developed in that very direction. There is, viz., Flanagan, a mild Celt and an enthusiastic admirer of law and order. We make him Chief of Police. There is the tribe Levy, with its timehonored reputation for honesty. We never elect a City and County Assessor but his Christian name is Levy. In former times we used to fill the office of Coroner by some undertaker, but since we discovered that these people really understand something about that business we take a doctor. Now, my friend, the circumstance of your being an unsophisticated Northern barbarian without any education would admirably adapt you for the office of Superintendent of Public Education; but some fellow pas-
sengers of yours have stated that you know some Latin; that, of course, disqualifies you forever. Now, I will tell you what I can do. I will create a new office for your sake and make you Inspector of Mothers-in-law."
Hearing this, Hans Meyer grew pale, went to the next blacksmith and ordered a dress coat, borrowed from a tinman a stovepipe and a pair of gloves, took a drink, and had a building erected on the same thoughtful style of architecture that he had studied during his stay at the Baltic penitentiary, and disappeared from the sight of man. After some weeks his friends entered the house and found Hans Meyer stark dead, in full armor, leaning against a corner. Some said he died by an abscess of the liver, others by brandy and water on the brain. Some contended that during his sleep rattlesnakes crept into his boots. The Coroner pronounced it a womb complaint, called affection of the mother-in-law.
vine Providence in its inscrutable wisdom," and the jury gave the verdict: "Killed by the inscrutable wisdom of Providence."
DARWINISM.
ON a former occasion our most gracious Sire has proved the descent of the human race from above; he has defeated the prevailing notion of our descent from the monkey, a theory which found its chief support in the homoeopathic maxim, Simla similibus. He has proved, not only theoretically, but also practically, with imminent peril of his life, the descent from the balloon.
One day when I was in these rooms, at an early hour, when all good Bohemians were embraced by the arms of Morpheus or were embracing somebody else, I was wrapt in a brown study about Darwinism. My state of mind was caused by a conversation with our brother Harry Edwards on a previous day, which resulted in a slight headache. I was absorbed in the contemplation
of some luminous phenomena and black dots before my eyes, spectral illusions, to which I am much subjected on lonely mornings, and which, perhaps, are the ghosts of the insects killed by me in the early days of California, when suddenly my attention was attracted to the cage of our sacred bird, the Owl. This at least was no spectral illusion ; there was a letter directed to me, the same which I hold here in my hand. I think I can excuse the indiscretion of divulging the communication made to me by the Owl, because it seemed to me as if the father wishes its publication. It is as follows:
"Before I addressed these lines to you I hesitated to choose between you and Rev. Bromley, whose nocturnal habits and personal appearance are so much like my own ; but, remembering the great consideration which you always have shown me by showing homage to me in entering and
leaving the room, I consider you the most worthy for the reception of my confidence in regard to my ideas on Darwinism.
"Before entering into particulars, I must state that Darwin's idea of progressive development is entirely wrong. This world has proved a failure from its very beginning. The tops of the mountains are washed down and fill the lakes and seas, causing trouble and confusion on all sides. The sewerage of the planet is bad everywhere, and the whole universe a system of blunders, a consolidated mass, the product of a long series of incompetent engineering of antediluvian Superintendents of Streets. The grade has been so continuously changed that you cannot find an alpine height without oyster-shells, sardine-boxes, and other marine productions, which prove the locality to have been originally the bottom of the sea; on the other hand, what is now the bottom of the sea is covered by a posttertiary stratum of umbrellas, peanut-shells, and broken bottles, a proof of its having
been but a short time ago a popular picnicground for Sunday excursions. These changes of grade took place chiefly to get a job for the numerous street contractors, by whom, at that period, this planet was mainly inhabited. The constant rotation of the planetary system prevented all investigation, and it was impossible to locate the blunders and mistakes and make individuals responsible, as everybody promptly blamed his predecessor. Mr. Post-tertiary blamed Mr. Jurassic; Mr. Jurassic, Mr. Lias; Mr. Lias says it is the fault of Mr. Eocene; Mr. Eocene says it is the fault of Sabbath-breaking and a bad kind of whisky. "One of the most striking failures in creation is man, who is nearly as mean as a deadly enemy of my race, the crow, who persists in persecuting me whenever I appear in daylight, and flies at me and calls me names. Just so mankind. Like the crow, he uses unfair means and has obtained by them a position for which nature has never intended him. He is an usurper, a
on this planet is the owl.
"The human race is fast degenerating. Look at the descendant of a Northern seaking selling liquor as an Angular Saxon at a corner grocery. Look at the descendants of Milesian kings drinking it on credit.
"The cultus of the ancient Aztec, with its impressive ceremonies of human sacrifices, has degenerated into the early piety of the Young Men's Christian Association. Compare the High Priest Huichtlipochtli, wielding in his right hand the sacred flint and in his left a bleeding, palpitating heart, to the Young Men Christian Deacon, with bald head, blue eye-glasses, a set of false teeth, and an umbrella instead of the sacrificial flint knife.
"As to natural selection, the idea is simply preposterous. It is true that we owls sometimes select our own kind for food, but there ends the working of that principle. Is it natural that on the top of the dentist you always find a photographer, above the undertaker a dancing-school? Or, explain why all your friends are more or less given to drinking.
THE MOSQUITO.
MOST GRACIOUS SlRE: The letter with which you have honored me has been to me a source of great anxiety, in consequence of its most original style of calligraphics. Brother Bromley, who always has been my adviser in spiritual things, but whom I am also in the habit of consulting in important worldly matters, took your kind letter in his hands and, after having turned it from side to side, addressed me with the following words:
"My young friend, this is a Chinese letter, and as Chinese is not written in lines, but in columns, you ought to have held it this way, and you easily would have found that it is a bill for washing and ironing. When I represented my country in Tien Tsin, I received every week a document of
similar character; in fact, it was the only official correspondence I indulged in during my stay at Tien Tsin. You see here Hong Kong Shanghai Peking Ironing Washington, and here in the corner is the receipt of the bill, 'You tarn fool,' which means, payment received, and is also the polite style by which foreigners are addressed in Tien Tsin."
This explanation did not satisfy me, so I interviewed Mr. Marshall, who has lent me several times valuable assistance in deciphering letters of Charley Stoddard and other Aztec hieroglyphs.
"That lets me out," he said. "The only advice I can give you is, apply to Charley Stoddard; he is the highest authority in this style of calligraphics."
received this answer:
"Yes, I recognize my own handwriting; but you know very well that I cannot read any of my manuscripts older than twelve months."
Then I did show the letter to Dan O'Connell, who read to me fluently an advertisement of a professor to teach waltzing in three lessons. " Some unknown friend," he explained, "has heard about your affliction by gout and recommends you this new
Now I have tried the cure, took the three lessons, but, as you see, without the desired effect. Nevertheless, I am confident I would have been cured if I only had learned to waltz. Finally, thrown on my own resources, I succeeded in rinding out,—
3. That it referred to something else whose nature was doubtful. The something read sometimes like dry goods, other times more like mosquitoes.
The latter version appeared to me the more probable, being the more appropriate one for a student of entomology. Neverthe-
less, it appeared to me the safest plan to combine the two versions into one, and so, by joining the mosquito to dry goods, I obtained the mosquito bar, a liquid body, which I used to take in Sacramento before going to sleep. This substance, it is true, would not protect me against the sting of the mosquito; but, when taken in sufficient quantity, would prevent my feeling the stings — in a similar way as Tommy Newcomb cured temporarily a toothache. It was in the old rooms of the Club, where one evening he was suffering, complaining, and expressing his firm intention to get drunk. Now, if Tommy had taken that vow, I do not know a single instance of his not being true to his word; so he succeeded very well that night, and when I met him the following day at luncheon with a swollen face, I was afraid that the cure had not taken effect; but he assured me the remedy was infallible, and added: "The whole night I had the most excruciating toothache, but did n't feel it because I was drunk."
The mosquito (Tipula pipiens) belongs to the class of Diptera, which class easily can be distinguished from the rest of insects by its species having one pair of wings and three pairs of legs. Angels also have a pair of wings, but the mosquito has the advantage in the number of legs. Nevertheless, most people prefer an angel with a single pair of well-developed legs, even if the wings should be wanting, to all the six legs of the mosquito. The jaws of the mosquito are so constructed that he cannot chew, only kiss. But he makes up for the weakness of his jaws by plenty of cheek.
In his larval state he lives in the water and is strictly temperate. During his aquatic larval state he breathes atmospheric air by a pair of tubes at his anal end. This, of course, necessitates his coming at stated times to the surface of the water and sticking out his anal end with the respiring tubes and disrespect of surroundings, which
movement is very improper. But Nature sometimes is very improper, and I have frequently to blush for her. Now, this anal end is analogous to the lower end of the spinal column of our own species, which in our own larval state is used for educational purposes, but never for respiration; and, I am happy to say, is not ornamented with a pair of tubes sticking out as in the mosquito larva, because these tubes would interfere with the present style of our dress, and would even prove a serious obstacle to our sitting down.
The moment the mosquito emerges from its chrysalis in the water he does not touch water again. He spreads his wings and looks for a mate. He can as little comprehend the associations of his larval state as we can comprehend the illusions of our first love. The male mosquito henceforth has for its only object to kiss the mosquita, but the mosquita in her turn is very liberal in her kisses. She kisses promiscuously; but, although having a pair of wings, her kisses
are not those of an angel, and she, therefore, frequently comes to grief. The male mosquito only lives to kiss, but the female frequently dies for it.
There is a peculiar propensity, a kind of suicidal mania, in the whole class of dipterous insects. The housefly, for instance, repeats suicide so frequently that with her it becomes a habit. It is the prerogative of the fly to cultivate suicide as a vice. I once marked a fly by tying a knot in her left middle leg and found the same individual next morning drowning in my eye-opener, then in my coffee, then in my lunch cocktail, then in my appetizer. In my pousse cafe I saw two of her, and when I took my nightcap I did not pay any more attention to her.
The mosquito does not commit suicide by drowning, because he hates water and is ashamed of his larval existence, breathing through anal tubes and feeding on animalculae not belonging to him, but to another class; as some specimens of our own spe-
cies are ashamed of their juvenile depredations in garden and fields, belonging, who cares to whom, and of the educational action of the rattan on the lower end of their spinal column.
Now, if we compare the diet of mosquito larva and his mode of respiration to our own style of living this night, ought we not to be thankful?
ON MEDICINE.
THE science of medicine is the science which enables the student to pass his medical examination. The object of this science is to keep out of the dominion of the News Letter, and if this end has been obtained we call it the triumph of science.
Medicine branches off into two disciplines, which are called the old system and modern science. The followers of the latter call the followers of the first "old fogies"; the followers of the former call the adherers of modern science " young men." The oldest system was that of the Haruspices in ancient Rome. They examined the bowels of oxen with the naked eye and predicted out of them what would happen. Modern science examines the bowels of fools with the microscope and predicts
what has happened. Both disciplines agree on one point: they collect fees, or at least try to collect them. This is a very essential part of our science, and the discipline that treats about collecting fees is called physiology.
There are many other branches of medical science, but still there are not enough. We have forensic medicine, and our most gracious Sire has created a new science by proclaiming Dr. Leach doctor of surgical music. But we want a doctor of obstetrical aesthetics. There is a secret but intimate connection between these two apparently so different branches of human knowledge, and the connecting link is woman, or, as we scientists say, "female mankind." It is a fact already observed by the ancients that as soon as ladies approach a certain age they begin to develop in their meetings the most lively interest for medical matters and medical men. We medical men feel frequently the powerful influences exercised in their secret tribunals, called lunch parties, where
they make and unmake medical reputations. Now, we think it a delicate compliment, and well calculated to appease the wrath of the goddesses, by creating for their honor a new discipline, called "obstetrical aesthetics. "
HEROIC DEEDS OF OLD BOHEMIA.
MOST WORTHY SIRE: You will excuse my gray suit on an evening like this. I wear it partly because it agrees best with my complexion, which is also old and gray, and partly because it is appropriate to the remarks I have to make on bygone days — gray antiquity and the heroic deeds of old Bohemia. These remarks are not entirely prehistoric; if they were, they would be out of time, instead of their being at present only out of place.
I am myself a kind of Bohemian fossil, and there are moments in which I consider myself an honorary member of the Lias formation. I can sympathize with the plesiosaurus of the Ward collection, of which a specimen is kept at our Academy of Sciences, which the Creator himself
never had dared to imitate. But we will not enter on this night into the dark mysteries of a Bohemian Lias formation. Let us become post-tertiary and remember the ancestral heroes that preceded the present generation.
There is, one of the first, the learned and energetic Caxton, alias Rhodes, the discoverer of the gyascutus, the quadruped with a short fore-leg and a short hind-leg on the right side. This animal was especially created to run around a mountain-side in Oregon, sufficiently distant to escape immediate investigation.
The more ancient Bohemians will recollect that this discovery led to an equally interesting discovery of a corresponding quadruped with a short fore-leg and a short hind-leg on the left side, and which by Divine Providence was destined to run around the same mountain from the other side. As these two animals proved to be of opposite sexes, this arrangement was evidently intended to introduce them to each other, and
is another proof of the benevolent although frequently frustrated intentions of Divine Providence. The discovery of the second animal does not belong to our Bohemian brother Caxton; we owe it to one of the appropriation scientists who occupies a position in Berkeley and in the hearts of our grangers, and who wants only an initiative to run through a whole series of discoveries.
But our learned and ever-watchful brother Caxton, as many will recollect, saved on another occasion our country from a dire calamity. It was in the year A. D. 1868, when a party that had spent the evening at the Cliff House discovered the moon in the act of approaching the earth at a rate that, according to exact astronomical calculations, would have brought that celestial body in sixteen days, eight hours, and thirty-five minutes in contact with the earth. As the clash would take place south of Market Street, and, as that part of the city had already previously suffered from
the Second-Street cut, real estate south of Market Street was falling rapidly. And it was not only the giant proportions of the approaching luminary increasing in mathematical proportion; nay, the member of the returning party even discovered a second moon, a satellite of our earth hitherto unknown to astronomers. The officers of the Barbary Coast Survey, it is true, had, by an algebraic formula perfectly known to themselves, succeeded in influencing the perigee in a way to make the moon fall on England; but our esteemed brother Caxton, with a penstroke and a little printer's ink, removed the whole danger. Some pretend that the moon, having spent all her financial power in railroad tickets, was not able to reach England and had been precipitated into the Atlantic Ocean. This probably did happen to that second moon seen by the members of the Cliff House party, as this second moon is missing since that time. Now, imagine the disturbance of the moon suddenly arriving in this country with a
You must recollect that in the year A. D. 1865 a chemist had discovered a substance, otherwise useless, that would ignite the hydrogen of the ocean. Now, in itself a burning ocean would prove an assistance to the McKinley bill, and, by cutting off import, greatly favor home industry; but, unfortunately, the fire would communicate to rivers and wells, and thereby prevent bathing, cleaning of bottles, painting in water-colors, and prove a great distress to our Fish Commissioners. Our Bohemian brother Caxton, whose watchful eye had espied the danger in time, offered from his own pocket an amount of millions that would have astonished even a Californian, as well as a corner drug-store, to the chemist to desist from his diabolical plan to set fire to the ocean; and as this malevolent
chemist asked for more millions and two drug-stores, our brother Caxton threw him from the platform of a railroad-car passing Cape Horn, which feat he also executed by a small quantity of printer's ink.
I am sorry to say that our Bohemian brother Caxton did not succeed in saving the unfortunate miner who drank the water contained in a geode and became petrified and fossilized in a time of twenty minutes. But his publication of the event has gone far to warn the public against that most insidious drink — water.
What shall I say in praise of the powerful McCracken Bungletoe, alias Tommy Newcomb, who, in his great victory of mind over matter, left Mestayer under the table, and with one foot on the body of the slain warrior and the other in the spittoon, asked for another horn of whisky? Or the great Apache chief and ancient mariner, RearAdmiral Cremony? But the latter has a worthy successor in nautical lore in the inimitable Bromley, under whose flag I dared
head began to swim.
In regard to tactics on a more or less dry land, we have General Barnes, who, as the Leonidas of the nineteenth century, fought in that terrible Amador war.
Alas! we cannot deny that many of the old members are no more with us; some have paid their tribute to nature, some have reformed their morals. But that wellorganized army of young Bohemia which I see before me is a guarantee that the future will be like the past, and that a bright time is in store for old Bohemia.
The bones of this fossil monster have been found at a depth of one hundred and twenty-five feet below the green sward of this beautiful earth.
It stands twenty-five feet on its legs, is twenty-five feet long. It has been found under one hundred and twenty-five degrees of longitude, which gives to the animal the enormous length of one hundred and seventy-five feet.
a photograph by Bradley & Rulofson. As you see here, the animal fed exclusively on boa constrictors. Anybody that has conferred with Montgomery Queen on the price of boa constrictors will know the enormous price of such luxury. So the unscrupulous wisdom of Divine Providence has endowed this beatiful creature with an unlimited capacity to live on credit.
Professor Huxley, in conjunction with the Alia California and other bodies of inscrutable wisdom with whom we have been in communication, agrees that this animal has lived one hundred and twenty-five years before the Flood. That arrow-head that looks like a fragment of a broken whiskybottle has been found near his left hindleg, which circumstance proves that this animal had sufficient mental power to run away from its enemies, and proves at the same time that the San Francisco Society to Prevent Cruelty to Animals was not then in existence. One of the enormous tusks
This giant skeleton has been sold to the British Museum for the moderate sum of one hundred and twenty-five thousand dollars, and here I am on the road to an independent fortune. Now, you will say, If that man is on the way to an independent fortune, why does he take all the trouble to lecture here every night by torchlight on the sidewalk, without any protection for his learned head but the canopy of heaven?
was always considered a high honor to preside on Christmas night, when the strictest privacy protects the impressive rites and dark mysteries of Bohemia. But under the present circumstances, when we are prepared to emigrate from this sacred abode to the distant shores of Pine Street, to prepare a new home for the Pilgrim Fathers of Bohemia, you will not object when I compare you to the Mayflower. This night is the last night that the sacred rites of High Jinks are to be celebrated in these rooms. It is the first time that we celebrate the last High Jinks. May they turn out to be everlasting.
Your name, illustrious Sire, will be handed down to posterity and will turn out an eternal botheration to schoolma'ams when they pass their examination; and both of us, when, with the assistance of my medical brethren, we have shed off this mortal clay, will form a constellation in the sky, called Major Ursus, or the Bromleyades.
At this moment begins a new era in the history of man, an epoch that even reverses some laws of nature heretofore considered of universal power.
Most illustrious Collega, you will recollect a private conversation once held in this sacred room when you justly remarked that we could pay our debts by mental powers. Colonel Hawes then said that Archimedes, a Syracusan philosopher, who received his name from the Archimedean screw, has established the law that the strongest man could not lift his own body, and that even our Collega Beverly Cole, when shipwrecked, could not lift himself out of the ocean by his scalp-lock, but required a boat
to save his valuable life. You will recall that important discussion and will feel proud of this victory, which Tommy Newcomb would call a victory of mind over matter.
ON DREAMS.
NIGHT-DREAMS are private property, — they belong to the individual; but daydreams are public property, and belong to the century, or a certain stage of social and scientific development. The day-dream one hundred years ago was the philosopher's stone and the transmutation of metals. It is a remarkable anachronism that in this enlightened age the dream of the transmutation of metals has been revived in Chile by Mr. Paraf, who persuaded the unsophisticated natives of that country to buy stock in an enterprise to transmute copper into silver. Now, we all know that gold and silver can be changed, but they cannot be transmuted. Silver, it is true, is a metal that dissolves readily in alcoholic fluids and precipitates out of this solution on the tip of the
process.
The dreams of our own age turn chiefly upon vital processes. There is another conundrum which we strive to solve, and that is the origin of organic life. We look no more for the transmutation of metals, but for the transmutation of plants or animals into other species; but the laws of our Society for the Prevention of Cruelty to Animals have put a fine on Darwinian experiments. We even suppose ourselves the victim of some transmutative process from a rather doubtful ancestry, and some prominent members of the medical fraternity seek with great care and perseverance for a connecting link wherewith to excuse their own personal appearance. But there exists no connecting link, for we are entirely distinct from all other types of creation by one faculty— that of smoking tobacco. The idea that the clouds are produced by the angels smoking tobacco is exploded ; it is in direct
Academy of Sciences.
It was one of the day-dreams of our ancestors that organic life, and even the human species, could be produced by chemical processes. Goethe, in the second part of his "Faust," alludes to this day-dream when he introduces the homunculus, a human being that was the result of an alchymistic process. At present there are many who believe that organic life may be produced by certain stages of fermentation. Fermentation is sin, even when the duty is paid, and Vinegar Bitters the only refreshment permitted to the faithful. The disciples of the fermentation theory quote an experiment by which they produce fleas by moistening sawdust. I have tried the experiment, but could not raise anything, not even a self-made man, and only after many complicated processes I succeeded in raising a life-insurance agent — and that only after having added to the sawdust an addled egg.
Now, my Bohemian brethren, you cannot derive much satisfaction from such results, and, I admonish you, if you want to produce organic life, follow the old, approved method founded on the Darwinian law of natural selection and mutual affection.
SCHILLER AND GOETHE AS BOHEMIANS.
THE first traces of Bohemian sympathies in Schiller we find in his dramatic play "Die Rauber," in a passage where one of those interesting highwaymen advises to withdraw to the Bohemian forests — a delicate allusion to our midsummer celebration. In Schiller's later career we find two other and more celebrated plays localized in Bohemia, namely, "Wallenstein's Lager" and "Wallenstein's Death"; but Wallenstein's death was not caused by lager, as is erroneously supposed by ignorant people. Schiller had a medical education, but practiced medicine only for a very short time; in fact, he has killed considerably more people in his dramatical plays than by medical prescriptions. In this regard he is much my inferior, but he is a greater poet. In his
later years he was appointed Professor of History at the University of Jena. If he had remained faithful to the science of medicine, he might have become Professor of Hysterics at the Toland College, like our Bohemian brother, Professor Dr. Beverly Cole.
Let us now investigate the Bohemian qualities of Goethe and his origin. Goethe's grandsire was a blacksmith, and, as our grand Sire is at present a Taylor, Goethe may consider himself our equal ; and so he was in reality, for when he studied law he joined an organization analogous to this. In his autobiography, headed "Truth and Fiction," he describes accurately the club and also the untimely end of this benevolent institution : The club was not careful enough in selecting its members. They admitted so many respectable people that the club lost its bad reputation, and then they dissolved with such violence that some members remained dissolute ever after. Some people say that in his book "Werther's Leiden"
Goethe advocated suicide, but, after all, this advocation was not without reason. Suicide, when properly directed, could be made very useful, like the "hara kiri" of the Japanese. If, for instance, all the members of our next Legislature could be induced to commit "hara kiri" before entering Sacramento, what a blessing it would be for this country! But as it is generally the wrong people who commit suicide, a careful government ought to warn them publicly by substituting for the antiquated advice, "Go to Hewston Hastings," the impressive words, "Commit no suicide." Goethe's most celebrated play is " Faust." Faust was a great conjurer who raised the devil and took a mortgage on his soui. The formula has since been tried by many people, but without any satisfactory result, for Old Iniquity did not appear; from which circumstance one may infer how much in these dull times the value of souls has declined.
MOST GRACIOUS SIRE AND DEARLY BELOVED BRETHREN: During the past year I have assiduously studied and diligently observed. When formerly the progress of morals was the object in which my energies concentrated, it is now progress in general. To this sole object I have sacrificed my whole time. I have lived like a hermit. I have withdrawn from society. I scarcely know the inside of a saloon or the outside of a bar, because I have steered my boat out of the wild breakers of the bar, where sirens sang to Ulysses, into the quiet port of peaceful domestic intoxication. I am here to offer you the results of my observations regarding morals, science, art, and things in general.
osophy is the only science in which, since the time of Socrates, no discovery has been made. It has been reserved for my own investigations to discover the important axiom that in a free country no citizen must be tyrannized by his own principles. In astronomy I have to record the recent discovery of an old split in one of the rings of Saturn. It is true this split was known before and was called "Encke's division," or, according to the reporters of our newspapers, "Yankee division" ; but the discovery of its exact nature was reserved for our Bohemian astronomer, Colonel Hawes, who has spent many nights watching the rings of Saturn through different glasses, and even bottles. According to the statements of this eminent scientist, the split in the ring of Saturn cannot be mended and is beyond repair. The practical importance of this fact cannot be overrated, for it is more than probable that all other rings will follow the example of Saturn and split; and when all those rings that at present prevent progress
As to forest culture, we have to record a most important step. The committee has empowered a posse of intelligent schoolma'ams of both sexes to plant trees on the roadsides. These trees will be exhibited to all passers-by for a nominal entrance fee as soon as the last of our forest trees has become extinct.
The insect world has shown through all the later years a perceptible progress and enjoyable tendency to copulate and multiply. We have had grasshoppers, codlingmoths, scale-bugs, and our most gracious Sire has treated successfully, by mercurial ointment, several cases of phylloxera in persons that had come in too close a contact with the vineyard of a friend. We are uncertain whom we have to thank for this revival of the insect world — our brother Harry Edwards, for his absence, or our State entomologists, for their presence.
farmers found sufficient reason to complain ; so the inscrutable wisdom of Divine Providence, whose pet is the California granger, sent us rain enough to give him cause to complain about inundation. This dispensation of Providence is still going on, because Providence has been long enough in office to know that as soon as it stops raining the California granger will growl about unusual dryness. So the rain goes on and a new deluge is fairly started. The more thoughtful members of our Academy of Sciences make preparations to transform their hall into a Noah's ark, in order to save all those animals in their stuffed state whose ancestors Noah preserved alive. The citizens of this State are much puzzled about the cause of the flood. Heaven so far has always shown patience to their shortcomings. They are not conscious of an unusual amount of wickedness, nor is there any California Legislature expected to meet at Sacramento.
attention to the wishes of the people. It is now twelve years since we have petitioned them to have Telegraph Hill converted into a volcano, so that, at appropriate times, we could have eruptions for the benefit of tourists who write books in Boston about California dynamiters, and eruptions of the skin are but poor excuses for a real volcanic eruption. This community of honest, harddrinking taxpayers is entitled to at least one volcano. We have been frustrated in our dearest wishes; nevertheless, we have to be thankful, especially as it would not help to be otherwise.
AND POLITICAL ECONOMY.
THERE are but few problems left for the investigation of the modern scientist. One of the most interesting problems is the still insufficiently explained relation between politics and alcohol. We have spent much of our own valuable time in the study of this problem; we have distorted Darwinism into the most impossible shapes ; we have invented a long series of evolutions; we have experimented on our own system by exposing it to the action of alcohol heated up to the production of vapor and then again brought it in contact with a glacial period sucked through a straw. Then we have searched history, ancient and modern, sacred and profane, but mostly profane. The re-
suit of these investigations was an enormous accumulation of collateral facts, and in regard to explanations a new hypothesis.
Homer in his Iliad is one of the first authors offering instances of the mystic relation between patriotism and drink. Wherever this reliable historian describes a meeting of the enlightened nation of the Greeks, he never neglects the aithopaoinon — the fiery wine. He minutely describes the depas amphikypellon used by the venerable Nestor when engaged in state affairs. Learned philologists explain the two handles so expressly mentioned by Homer as means to handle more easily a cup of proportions unusual even in the heroic age; for the inspired poet and historian states at the same time that ten mortal men as they are nowadays could not have emptied it. Alas ! the world degenerates, and the cups of our days are small and have very thick bottoms. Homer also carefully notes down that before any decisive step in politics was taken the heroes took a quantity of
wine in proportion to the importance of the case : " Autar epei posios kai edetyos ex eron hento" A similar custom must have prevailed amongst the Romans. We are not quite certain, but we think it was Cicero or somebody else who first pronounced the axioma : " Vox populi, vox whisky." We now recollect distinctly the passage is to be found in Cicero's book "De Officiis," or, The Surest Way to Get into Office.
Julius Caesar also, when about to cross the Rubicon, spoke the historical word: "lacta alea esto," — Let us shake for drinks.
Now, the same phenomenon related by the ancients is witnessed, and let us say is religiously observed, by our contemporaneous generation. But you will see a very material change in the system of administering the alcohol. With Homer it is always the kings and heroes that do the drinking, and the people the paying; but during the republican government of ancient Rome the people do the drinking, and, exactly as it is in our own country, the wealthy or those that
want to become so pay for the drinks. You will observe that all political meetings, may their principles be as divergent as possible, agree in one point: after having saved their country they adjourn into adjacent barrooms, where they mix their public spirit with kindred spirits. You will say our Academy of Sciences acts differently, but you forget, firstly, that our Academy is a scientific, not a political body, and, secondly, that there is no decent barroom in the vicinity.
Now, this intimate relation between patriotism and alcohol has even entered our English language in the expression, "A man of public spirit," by which expression we infer that this worthy man takes his spirits publicly with boon companions whom he treats, but not in the solitude of his domesticity.
This is all very clear and intelligible even to the unsophisticated mind of a San Francisco city father, but now comes in the question how to account for this phenomenon.
We have stated before that we have experienced and investigated and have come rather near the solution of the problem, which is a chemical one. Here is our explanation : Political questions have no affinity to water. This is a conclusion a priori, for we have not tried the water. Neither are they soluble in fixed oils ; we have tried castor oil. Now, it requires very little chemical knowledge to see that alcohol, cold or heated up to a reasonable degree, is the only menstruum in which political questions are soluble.
ETHNOLOGY.
I AM certain you are astonished to hear me lecture on a subject so unfamiliar to me as Ethnology. It is the fault of our most gracious Sire, who ordered me to do so. He probably meant Entomology, but I understood Ethnology, and as this happened after six o'clock P. M., I am not quite certain on whose door I have to lay the cause of the misunderstanding. In such cases I always lay it at the door of the other fellow, who in this instance is our most gracious Sire.
I at first intended to follow the custom of my fellow-scientists — that is, to compile an ethnological or entomological paper of plagiarisms, in which only the errors are my own; but, on more mature reflection, I thought, as Alexander von Humboldt is
dead and Frank Pixley alive, I would not run the slightest risk to be discovered in drawing from my own bold and lively imagination.
The first stage in the existence of all nations and humanity in general is that of Midsummer High Jinks, differing from our present ones only by a large supply of nothing to eat and to drink, but agreeing with it by a total absence of houses. I am not prepared to state the exact time to which this state of affairs has lasted, but I am convinced that at the time of Julius Caesar — the author of several Latin text-books still in use in our colleges — a change must already have taken place, because this J. Caesar wrote a book, "De bello Gallico," which, as a member of our Board of Education has informed me, means "On the beautiful Calico." Now, these words would infer that the state of society had changed into that of a picnic, if it were not for the frequent occurrence of the word "castra," which word I distinctly recollect means
The present Midsummer High Jinks are a decided improvement on the original article, which I have closely studied during my stay in Australia. By the kind recommendation of Captain Schenck, I received an invitation from the daughter of an Australian chief to assist her in arranging a cabinet of insects, which she carried about her through all the wanderings of her tribe. I accepted the invitation, arranged the collection, exchanged specimens, and, as the office of State Entomologist was already filled by an intelligent carpenter, I was received in the bosom of the tribe, obtained the right to vote and at the same time different degrees of relationship, with all the privileges otherwise only conceded to Irish cousins.
Owing to a failure of our crop of kangaroos, we had to live chiefly on missionaries. Whenever the supply was exhausted
we took to stealing sheep, which change of diet at last aroused the British lion. For weeks I had breakfasted, lunched, dined, and souped on mutton. My hair, formerly straight, began to curl and grow crisp by the constant feeding on the wool-bearing sheep — as you can see now — when the catastrophe drew near. The battle was imminent. On our side, naked bodies, wooden spears, and the trust in Divine Justice and our swift feet; on the other side, thoroughbred horses, Minie rifles, and the untamed courage of the amateur soldier. The words of our valiant chief are still ringing in my ears; " There," he said, "is the enemy of our homes. Most of them are fat, tender, sleek, and in splendid condition. They will require but little cooking to be very nice. At present they are not nice ; but who would be afraid to die when the honor and glory of his country is at stake? It is not hard to die ; the biggest fool can die, and I have seen them do so frequently."
war-whoop and then followed the example of the valorous chief and climbed each a gum-tree. We gained by this maneuver the most decided victory, because the horses of the enemy got frightened and ran away with the valorous warriors of the home guard, with the exception of a few bold men whose horses refused to run and took to kicking. Those men, after having made us a present of their horses, tried very hard to join the corps d'armee. We hoped they would succeed, and ate their horses. As these horses refused to talk, it will remain a mystery forever at whose instigation their fellow-horses ran from battle. I am certain it was no bribe from our side; perhaps it was a strike for higher wages.
Alas! those happy days are passed, and I am the only survivor of that once powerful tribe. The men have been shot by prejudiced shepherds and cattleherders; the unprotected females have served as food to their affectionate neighbors; and at present I am the only living man that
language.
Alexander von Humboldt mentions in his travels a certain parrot, the parrot of the Atures, who was the only being that talked the language of that extinct race. That is exactly my case. It remains now to draw a moral for you and administer the customary admonitions :
Secondly, let us keep up the difference between the original Midsummer High Jinks and our present refined celebration by always laying in a good stock of good things ; and
ON COMMERCE.
I AM not here to discuss Christmas from a dogmatic point of view; that has been done by our most gracious Sire and other pulpits of this city. I am here to discuss a new side of the question — the commercial one. Christmas is the time when we are expected by the whole world to settle our bills, instead of running up new ones. A friend of mine, and at the same time one of the greatest authorities in Bohemian financiering, invented a new commercial system by not paying the old bills and letting the new bills grow old. It is his view on commerce which I am to develop here.
The word "commerce" is derived from the Latin merx, genitive mercis, which does not mean mercy — of which commercial people show very little to each other.
Merx means a ware, and mercari to trade. The Greek verb peirao signifies the same, but its verbal substantive peirates does not mean a merchant, and is a proof that the ancient Greek knew life-insurance companies, syndicates of mines, and similar institutions as well as we do. There are several institutions in mysterious connection with commerce; for instance, the Custom House. This institution was created for two different purposes: First, to cause investigations; secondly, to break the antennae of the butterflies imported by our most gracious Sire.
As the surface of this planet is divided into dry land and ocean, so is the commercial community divided into dry-goods merchants and liquor-dealers; but, according to the Bohemian system, they are classified as such that give credit and others that give none. There is a close connection between interest and capital; for instance, British interest will suffer when the Turkish capital is lost. But as the true Bohemian
seldom receives interest, but frequently has to pay it, he will not be such a fool as to fight for any interest. And so I hope you will all join me in the pious wish : " Peace on earth, good will to men."
PREHISTORIC RELICS.
WHEN Montgomery Avenue was begun, I expected that the earthwork necessarily connected with grading and cutting through would bring to light interesting documents of prehistoric life on this coast. My most sanguine expectations were realized, and I succeeded in securing the interesting objects which you see here and which will form the nucleus of a most valuable archaeological collection.
The objects which are before you were all found on an area extending from the corner of Montgomery Avenue and Jackson Street to a point near Stockton Street, where an empty lot is crossed by the I45th meridian.
There are ample proofs that all this district at a remote period has been covered by the sea — in fact, was the bottom of an ocean. It probably was not then inhabited by the human race, and all the objects of human skill which you see before you date from a later period.
proof. You see the remains of
a bivalve, closely related to a now living species. And here you see another example of how the sagacity of the modern geologist from an apparently insignificant object draws the most important conclusions and establishes facts of the highest scientific interest.
the unit to be used in our calculation. As the ancient Greeks had their chronology arranged in accordance to the anniversaries of the Olympics, where the tribes of this gifted race assembled and competed for the crown of the laurel, so the California geologist arranges his chronology in correspondence to Legislatures, California Olympics, where all the talent, the honesty, the virtue, the wisdom, the beauty of this country meet and conglomerate into one enlightened body. Now, if we remember that it took five California Legislatures to ruin one geological survey, we easily can form an idea how long the tertiary period must have been during which the antediluvian Gryphaea developed up to the intellect of the now living oyster.
You see here several hollow cylindrical bodies of a substance that by our State Chemist has been pronounced a silicate of potassa. These bodies have proved a great puzzle to archaeologists, until, by my untiring researches, it has been estab-
lished beyond a doubt that these bodies were objects of public worship. The prehistoric Indian imagined them inhabited by spirits, powerful but benevolent, to whom he brought offerings of small pieces of metal. The silicates are found in a state of more or less perfect preservation and in great profusion throughout that whole region, and bear testimony of the most early piety of the red man. In some excavations they have been found numerous enough to form strata; these probably were places of public worship.
It was in the fourth year of our Bohemian era that it came to pass that a great prophet arrived from China, who instigated the people to destroy these idols, and converted a great many to the Five-Gallons Monotheism. The object of their worship was the great spirit of red noses, called "LokAh Lo Pshon."
one to six. Their use was till lately a mystery to science, and I am indebted to our Board of Education for the explanation of these curious implements. According to their statement, they were called bones by the prehistoric Indian, from the Latin words "bonus bona bon," which means a bone, for they were made out of the bone of the untamed mastodon of the plains. They served for the instruction of children in arithmetic. They have been tried by the Board and found very useful in complicated calculations about spiritual matters.
As you see, the points do not exceed six. The Indian did not count more than six. The decimal system was not yet invented, and the Indian of the period relied on his sexual system.
This object for a considerable time was inexplicable, until I succeeded in restoring it to its original form.
OUR Bohemian brother, Dr. Nuttall, has enlightened us on the subject of Irish rhetorics. He has quoted specimens produced by Irish ladies when in a state of virtuous indignation or otherwise excited. But what is Irish elocution when compared to Irish history? Irish history is a history of itself. It is entirely original; it does not connect with the history of any other nation, or even with the history of the world; it is independent from chronology, or even real facts.
There comes the Fenian, the Milesian, the Erse. Nobody knows where they come from, and we only entertain a dark suspicion where they go to. They do not connect with collateral history otherwise than by the name of some great Irishmen that
appear in Greek and Roman history, viz., Ovid, Virgil, Terence— the "us" of Ovidius, Virgilius, Terentius, being merely added partly to accommodate the second declension, partly as a compliment to the United States. At the dawn of Irish history we find Orion, who, in recompense for the valuable advice which he had given at the creation of the world, got a position in the sky, where he still forms a constellation; and it is a comfort in these turbulent times to see at least one Irishman keep his position, unaffected by the rotation of other celestial bodies.
BOTANY.
THE first attempt at botanical classification was that of Pliny the Younger, who, after having failed as a stockbroker, was by the influence of a body of Haruspices in Rome appointed Professor of Botany in Pompeii and Herculaneum. He did not cause the eruption of Vesuvius, as some inaccurate historians contend, but he perished in it, and wrote afterwards a very valuable description of this most interesting catastrophe.
This ingenious scientist divided the whole vegetable kingdom into the following classes: Trees, shrubs, vegetables, chicken-salad, mushrooms, coffee, wines extra. All plants not belonging to one or the other of these great classes he lumped
take any further notice of them.
You will perceive that in this system there are six classes; the decimal notation was not yet invented, or there would undoubtedly have been ten. The ancients counted only to six, and as a natural consequence had to rely upon their sexual system. This system was afterwards improved by Linnaeus, who based on the same immoral principle his arrangement of twenty-four classes, of which the last, the Cryptogamia, is the only decent one and the only one whose study could be recommended to the Normal School, if they modestly refrained from examining it with the naked eye. This state of things could not last, and the Natural System was invented — a system which differs chiefly from the Linnaean by the male flowers being called "staminate," the female " pistillate," or vice versa. There are several natural systems, all of them more or less important, and it was left to my own exertions to de-
vise a botanical system founded on new and entirely moral principles. I divide the whole vegetable kingdom into two classes: Eatabilia and Non-eatabilia.
Let us first discuss the Non-eatabilia, which class is again divided into several orders. The most important of these are Smokeabilia, Smellabilia, and Intractabilia. The order Smokeabilia is too well known to the members of this institution to require any further discussion. Most of the Smellabilia belong to the natural order of flowers, and are used for different purposes ; for instance, bouquets presented to ladies. Their color is of great importance. At marriages we present by preference red flowers, signifying the blushes of the bride, which vary in intensity from carnation to fuchsia, but generally keep to the shade of rouge, bought at a reliable drug-store. At funerals the flowers are white and blue, the white being the symbol of the moral purity of the deceased, the blue representing the state of mind of the mourning friends, and
patient died.
The highest order of this class is known as Intractabilia, and consists of those plants which are used for educational purposes. They are, the hazel, the birch, the rattan, the bamboo, which is used for tropical improvement of the mind, and the lady's slipper. All these substances act on the mind by being brought into quickly repeated contact with the lower end of the spinal column. My esteemed collaborator and college professor, Searby, and myself owe all our moral excellence to similar demonstrations a posteriori.
I come to the second class — the Eatabilia. It is divided into three orders: i, those which may be boiled ; 2, those which may be roasted; 3, those which may be taken raw. This reminds me of a thrilling adventure in the bold career of the naval hero, Captain Schenck. During one of his perilous voyages on the Pacific Ocean he
visited his friend Liti-Li-Li-Ho-Ho, the powerful king of the Cannibal Islands. The king received his guest with all the pomp and honor usual in his cannibal empire. At the feast given in the Captain's honor the neighboring trees were decorated with girls bound fast and awaiting the moment when they should be served at the royal table. One of the most toothsome was destined for the dinner of the distinguished guest; and when the Captain was asked in what style he would have his girl served up, he astonished his cannibal friends with the words: "Your Majesty, I'll take mine raw." Now, my friends, let us continue to lead a more virtuous life, so that when in our hereafter the question is raised in what style we shall be served, our guardian angel may sing out like the Captain, "I'll take mine
THE AGE OF IRON.
WE have all been charmed by the mediaeval love of the great Scotch bard; we have identified ourselves with the valorous knight, and have fought his battles, made love to the Baronet's daughter till the romance came to an end and we had to return to stern reality, Latin grammar and the problem of Euclid.
Our sympathies with the champion of bygone days is but natural, for we are his lineal descendants and lawful heirs. The Bohemian is the knight errant of the nineteenth century, only he wields the pen instead of the battle-ax; his enemy is no more the feudal tyrant, but the modern fool; he owes his dress-coat to the tailor, not to the blacksmith. But the romantic instincts of
hemian heart
How we would enjoy it if suddenly this room would transform into a feudal hall, the flames of the gaslight into torch-bearing serfs! Here we sit at a long table, clad in steel, the trusty sword on our side. A blast of a horn pierces the air. It is the signal of the warden placed on the battlements of the tower, not the toothorn of the festive hoodlum. It is not New Year which is approaching; it is a noble guest who reins his courser at the portcullis.
Hark the sound I It comes like a distant earthquake in search of a situation. It comes nearer. It mounts the staircase like a walking blacksmith-shop. The door flings open, and in steps the valiant knight, Sir Godfrey de Newcomb from Sacramento, He takes off his iron overcoat and hangs it on the hatstand in the hall ; he puts his iron umbrella in a corner; he blows his nose with an iron handkerchief. With sounding step and clanking armor he strides
into the banquet-hall, gazes around him, and his proud eye meets the eye of Sir Walter de Mestayer Sir Godfrey de Newcomb deliberately pulls off one of his iron gauntlets and flings it on Sir Walter's pet corn. A wild combat ensues. Sir Godfrey fells Sir Walter to the ground, he puts his knee to Sir Walter's chest, his poniard to his throat, and bids him to acknowledge that Sir Godfrey de Newcomb's lady love is the greatest beauty of all ages and countries. Sir Walter pleads that he has not the advantage of a personal acquaintance, never having been introduced; but Sir Godfrey tickles his throat with the poniard, and Sir Walter signs the certificate.
Alas! these happy days are gone forever. The age of iron has passed. It is true we have in this country considerable brass and steel — sometimes more than is agreeable to taxpayers; but essentially this is an age of flannel and underwear. And still the age of iron has not passed away entirely; it survives in one form. Don 't be afraid ; I do not
refer to the railroad. The
knight wore the iron rings to protect his frame, the maiden wears them to correct her frame and to expand parts of it into the proportions required by an age of taste and refinement.
But not only the body expands in our century by concentrically and spirally arranged iron implements ; the mind expands as well. Look! Here is the iron tool [drawing a crinoline] which makes spiritual comfort accessible, at the same time, in its spiral line, the emblem of all spiritual progress, which since thousands of years prefers the spiral to the straight line.
ANCIENT BOHEMIANS.
THE wanderer who strives to gain the glory-clad peaks of Alpine heights turns round at certain points to view the scenery of the valleys through which he has passed on his road to the mountain-side. So do we Bohemian wanderers. We also have the wise custom to turn round at the end of a year and eye the past with the eyes of the present. Let us then have a retrospect as it behooves members of the ancient organization.
The first traces of Bohemian existence are lost in the dawn of prehistoric times. It seems a well-established fact that at the time of the Lias formation Bohemians did not exist. The beautiful creatures whose remains we find imbedded in the Jura limestone have been identified by modern scientists as species of pterodactylus, and it was only the angel-like wings combined with
The first certain traces of Bohemians we find in some highly ornamented sculptures in the Pyramids of Egypt. The artists of that remote period were Bohemians, and had the thoughtful custom, when they had to represent their gods, to take the models from their Bohemian brethren. Of course, they always selected for that purpose only members of characteristic beauty and purity of morals. We have here quite a gallery of well-executed copies from sculptures of that origin.
Another trace of prehistoric Bohemianism has been found in the lacustrine dwellings of Switzerland that nowadays excite the curiosity of the archaeologist as much as the shell-mounds of California. In the re-, cesses of these ancient habitations, together with split marrow-bones of the mastodon, arrow-heads, and other flint implements, was found a bill for monthly rent of a
not receipted.
In the same rate that we approach historic times the evidences of Bohemian existence multiply. You all have a vivid recollection of the Greek expedition headed by Jason that started in the year 1690, before our Christian era, for the gold mines of Colchis. Most of the Greek heroes of that period had largely invested in a mine which so considerably had fleeced them that ever afterwards it was known by the name of the " Golden Fleece." Jason, with the other heroes, chartered a steam-tug, called the "Argo," and went for ^Eetes, the superintendent of said mine and father of a most accomplished daughter, by name Medea, who was a great astrologer and fortune-teller. The word "medium" is derived from Medea. Jason tried to get some points out of her and succeeded but too well. Each hero made his pile. After having sold out, they returned in the same craft;
but the "Argo," overloaded by fortunes carelessly stowed away, sprung a leak, and at her arrival at lolkos was condemned by the naval authorities of that place. So they sold the old ship to the Government of the United States for a man-of-war and started a paper.
One of the most interesting documents has been unearthed by Mr. Schliemann, so justly celebrated for his excavations in Asia Minor. On an excursion into the ancient kingdom of Bithynia he discovered the monument that marks the ashes of the unfortunate Carthaginian, Hannibal, who, on his flight from the Romans, ended his luckless career by taking poison. Mr. Schliemann published a translation of this most interesting inscription. It runs thus :
This is to certify that General Hannibal, a native of Carthago, came to his death by an overdose of nitrate of strychnia; administered by himself. Nobody to blame.
COMMIT NO SUICIDE
As our time is valuable, I have to stop here, but will read you on another occasion the second volume of this historic work, which contains the period from the Roman King, Numa Pompilius, to the Californian Senator, Paul Neumann.
OF all the innumerable virtues which I am constantly practicing, temperance has always been my pet; and for good reasons. St. Origen, one of the highest Bohemian authorities, speaks in terms of profound and just indignation of a sin of such magnitude that it requires two to commit it. Now this sociable and otherwise rather agreeable sin must have a counterpart, or antagonist, in some double-barreled virtue, or else vice would have an advantage over virtue and would be more perfect than virtue, which is absurd. Looking over the long index of virtues practiced in this Bohemian congregation, I find temperance the virtue and counterpart of the social sin condemned by St. Origen, because we never commit a temperance without inviting a friend. Now,
my beloved brethren, this is all clear and intelligible; and, theoretically, temperance would be all right, if it were not for the existence of serious obstacles and grievous mistakes in regard to the practice of the virtue.
There are some benighted people who mistake total abstinence for temperance. Temperance is moderation in all things; total abstinence is an extreme, and as such intemperance in its worst form, because it is unnatural. Temperance is the territory that separates two extremes. Between arctic ice and the scorching heat of the tropics stretches the temperate zone. This zone is inhabited by the most temperate nations — the Americans, the Irish, the Dutch; and this is not the only circumstance from which it received its name; like the temperate zone, temperance is the intermediate state between total abstinence and total intoxication.
Through a given room diagonally.
There is another even more serious mistake interfering in the sacred cause of temperance. There exists in the mind of many people an erroneous impression that water is the most temperate beverage, and, I am sorry to say, there are fanatics who really use it as such. My dear brethren, water is really a very useful fluid. It was created for washing, for bathing at the Midsummer High Jinks, for the sale of nautical instruments, for painting in water-color, for the construction of bridges, and last, but not least, for the cleaning of bottles.
We have here in this town a microscopical society whose members are visible to the naked eye and derive their name from the circumstance that they look into glasses of the microscope. Each member of this society will state that each drop of water
swarms with myriads of living beings, each provided with individuality and actively engaged in the pursuit of happiness. We also have here a society to promote cruelty of insects to man — no, to prevent cruelty to animals. This society recognizes two reasons which justify the taking of animal life; but under no circumstances are we permitted to inflict tortures on living beings; and would it not be a torture for these myriads, engaged in the pursuit of happiness, to be exposed to the horrors of our intestinal tube? Before swallowing these poor aquatics we have to kill them, in as mild and pleasant a way as is compatible with the process. This object we obtain by diluting the water with alcohol, a method agreeable to both parties and at the same time administering spiritual comfort. Dr. Swan, who frequently assisted me in the diluting process and aided in my experiments, has seen through a microscope of 2,675 horse-power the microbes, during the diluting process, joyfully clapping their hands and singing
out: "Death, where is thy sting? Hell, where is thy victory?" which means, in the language of microbes, "We won't go home till morning."
A NEW PHILOSOPHICAL INSTRUMENT.
I WAS very much at a loss by what token I could show my friendship on such a festive day. Pondering over this subject, I entered the hall of our Academy of Sciences, where I am accustomed to take at regular intervals my semi-monthly nap. From this I was startled by a lecture given by our learned Professor of Meteorology, who developed a new theory of heat produced by inverted comic action of irradiating ether. He accounted for the length of day in summer by expansion. The day is in summer expanded by heat, and contracts in winter even beyond its natural volume by the action of elasticity. The learned Professor also produced a philosophical instrument uniting in itself the merits of thermometer, barometer, aneroid, theodolite, corkscrew,
indispensable to the traveling scientist.
You may ask how I came into possession of this valuable instrument. I borrowed it for an indefinite space of time. This is my system, but, I am sorry to say, practiced by many people without their giving me credit. Before I hand over to you this valuable instrument I have to give you some instructions as to its use.
When placed outside doors in a prominent position, this instrument will indicate every current of air by pointing to the opposite direction. As our temperature is regulated by such currents, the instrument will act as a thermometer.
You ascertain the amount of atmospheric water by the circumstance that the instrument gets wet when it rains. By a simple algebraic formula you will find abundantly the inches of rain fallen during the season, and a fraction that perhaps might remain undissolved you may donate to our grangers, who never get rain enough, or distrib-
ute it amongst the picnic parties that at present destroy the peace of mind of Harry Edwards and other butterfly catchers.
You all know the difference between a meridian and a clothes-line. This instrument, placed on a meridian on the point where it crosses a degree of latitude, will show the exact geographical position of the locality by remaining in that position.
As to electric tension and the deviations of the magnetic pole, I leave it to your own philosophical mind to find out the use of the instrument.
EDUCATIONAL METHODS.
LITERATURE is the expression of civilization; civilization itself the product of education, and education the result of certain demonstrations a posteriori by which the juvenile mind is propelled on the path of wisdom and science. According to the origin of the material which is brought in contact with the lower end of the spinal column, we distinguish several different circles of civilization, which at the same time serve as types to peculiar forms of literature. All the material used for educational development is of vegetable origin, and in discussing our object we must first separate material of monocotyledonous growth from those of dicotyledonous.
contradiction in adjecto. It is an antediluvian type nowadays, only to be met with, together with analogous organisms, in tropical countries and in some sequestered corners of the southern hemisphere, where this vegetable anachronism has not found powerful competitors in the battle of life. It is the true emblem and image of the monstrosities and inconsistencies of Chinese civilization, whose promoter the bamboo has been for one thousand years.
The rattan (Calamus Rotang) possesses considerable advantages in its civilizing power. It is a palm-tree, scarcely an inch thick, but sometimes more than four hundred feet high, or rather long, leaning on other trees and supported by brush-wood. The rattan is the promoter of Hindoo civilization, and that most extensive epic poem, the Mahabharata, is the true picture of a palm-tree four hundred feet long and only one inch thick.
peated external application of dicotyledonous growth. There are two trees nearly equally productive of humanitarian principles— the hazel and the birch.
The hazel (Corylus avellana, L.) has its sway in southern and eastern Europe, where the Mecklenburg government, in its paternal care for the welfare of its subjects, prescribes by law the length and circumference of the hazel used for civilizing purposes. Austria employs this medium chiefly for military education and owes to it most of its victories. It is the hazel which infuses patriotism into an army otherwise divided by race, language, and interest. In hoc signo vinces is the motto of the Austrian hazel, and it is under the holy hazel-tree that Slavonian, Hungarian, Roumanian, crowd and fight.
The birch is the originator of AngloSaxon civilization and the kindred types of Scandinavian and German. Its eastern boundary is the Elbe River, where the realm of the hazel begins. Being born near
this river, I have enjoyed the advantages of both educational systems. I have been laid low under the hazel and have writhed under the stimulating influences of the birchrod. The hazel has its advantages, but for classical education the birch always has been preferred. In fact, I consider this tree indispensable; and, furthermore, I am convinced that without its demonstrations a posteriori nobody ever can master the irregular verbs. To me it always was one of the inexplicable mysteries of ancient history how, without the assistance of this useful tree, the Romans ever could have learned Latin. It is evident, however, that in the essential points their method of imparting knowledge did not differ materially from ours; the name of their celebrated and still consulted lawbook, Podex J ustinianceus , is one of the many proofs of this circumstance.
There arises now the question which plant will be the emblem and promoter of the civilization springing up from this new
center on the Pacific, of this literature born in our midst, whose juvenile pranks and freaks we are enjoying so frequently in these rooms, and whose manly strength and power we like to paint in anticipation. The coniferous trees of our mountains do not yield educational material. The ruling vegetation of our plains is tarweed and wild mustard. The tarweed is quite out of the question, for it has no civilizing power. As to the wild mustard, its substance is too brittle to produce any impression on the organs by which we influence the juvenile mind. It is not the raw material, not the body of the mustard which acts on the human mind; no, it is its soul which acts on the human soul. By careful and judicious experimenting, the celebrated pedagogue, McCracken Bungletoe, has demonstrated how the most beneficial results may be obtained by squeezing the seeds of the mustard plant, adding warm water, and applying the mass obtained in this way on the same region of the human body on which, accord-
rattan, hazel, and birch were applied.
So a benevolent nature has provided ample means for the promotion of California literature, and the method to utilize our vegetable resources has been discovered by the scientifically trained mind of a true philosopher.
IMMORAL PHILOSOPHY.
MOST GRACIOUS SIRE AND DEARLY BELOVED BOHEMIAN BRETHREN: Through the whole year I have looked forward to this day. I have collected most carefully every fact connected with Bohemian progress and goodness, and now I am here to give you all the important discoveries of our last year. It is true the new vice so long sought for is not yet discovered, but that is not my fault, nor is it owing to the neglect of any other member of this organization. On the other hand, we have made the most astonishing progress in immoral philosophy.
You all recollect the important discovery made by our brother Daniel O'Connell, who, having found out that the present system by which everybody confesses his own
sins does not work well, improved the institution of confession by the amendment that henceforth everybody confess the sins of his brother. Especially among the sisters, this improved form of confession has worked wonders, and some of the sisters have not stopped confessing from the moment when the amendment of our virtuous friend, by Bohemian authority, was adopted.
I now come to record another great discovery in immoral philosophy made by our great brother in the interest of Truth. Having observed that the present system of questioning witnesses and experts under oath is a frequent source of that most heinous of crimes, perjury; and having at the same time discovered by many experiments, carefully conducted by himself, that in betting people are universally conscientious and always bet only on what they, by their best knowledge, consider true, our Bohemian brother proposes that, instead of taking the oath, the said witness or expert enters
a bet at a reasonable amount, sufficient to protect his veracity. The advantages of this system are numerous and evident:
1. It protects the sacredness of the oath, which ought not to be defiled for worldly considerations. The oath has to be used partly as a punctuation and partly as an expletive. In both capacities the oath belongs to grammar, not to law.
2. Oaths, as we all know, are recorded in heaven, and our system, by which a notary public simply enters a note referring to the bet, saves a world of trouble to the recording angel, who now, besides his office duties, may attend to other matters; for instance, may attend lectures on obstetrics, or study law; so that, in case of a change in celestial politics he were to lose his office, he could make his living, without becoming a terror to the free-lunch system.
3. There will be considerably more solemnity in the proceeding and a powerful laconism if, instead of the common phrase "I solemnly swear to speak the truth and
154 THE HOOT OF THE OWLnothing but the truth, so help me God four bits," the Judge simply but emphatically says, "You bet."
I could mention here a great many other advantages resulting from this most valuable suggestion of our distinguished brother, Daniel O'Connell, but it would be like carrying owls to Athens. I only take this opportunity to point out the folly of importing a Professor of Moral Philosophy from a far-off land when we have in our own midst moral philosophers and great minds like our brother — as you see, without any appropriation. Now, you may imagine what moral giants we would have raised if a pure-minded Legislature had voted an appropriation for a public inspector of morals, a deputy, and county officers of moral philosophy.
It is true our California climate has lately been injured by too many brass bands in the streets of San Francisco, but the virgin soil of California is still capable of producing any crop desirable to an enlightened com-
munity. We raise any kind of scientist, from the practical miner up to the professor of surgical music or medical ethics, by simply putting on California soil the manure of an appropriation. Just as the mushroom in its natural, uncanned state springs from the dung left by benevolent cattle on an otherwise barren field, so by forming a little dunghill we can raise any variety of the practical miner and granger scientist.
Brother Daniel O'Connell at the Low Jinks will lay before you a petition to our coming Legislature where you are to sign your name, each with the mention of a small sum to be utilized to act on the pure minds and giant intellects of our legislators.
chiefly found in the temperate zone, but not always of temperate habits. Most of the specimens live in clubs and look very much like the common species (homo pater familias), from which, in many instances, he can only be distinguished by his habit of keeping late hours — up to the dawn of morning —when he tries to make a face as if he had his coffee and to talk early piety.
In the first stage of his existence it is impossible to distinguish the bachelor from the common species. He spells, studies grammar, crams big words without knowing their meaning — like ordinary mortals. He fights indiscriminately with his own species, burns firecrackers on the Fourth of July, falls in love; but here is an essential difference —
he marries not one of his many first loves. Only when podagra or old age prevents him from going to the club, and he thus falls into a state of general demoralization, he flies sometimes to matrimony; but even then he does not marry, but is married.
He is an admirer of
the sunrise, but is not an early riser himself. He admires the rise of the sun in going home or in stopping at a lamp-post, in whose embrace he sometimes apostrophizes the luminary of the young day, calling him Helios, Phoebus, and other bad names. The bachelor takes his coffee in bed; he then spends some time in arranging his locks in a peculiar economical way by making a small number of hairs go very far to cover a great surface of shining epidermis. In a later stage of his development this care is abandoned for the possession of a wig, and so for the morning hours remains only the sacred duty to communicate by rubbing the
skull, by means of a silken handkerchief, to a higher degree of polish, which nevertheless is modestly hidden under the wig when steps, especially those of a lady, are heard approaching the sanctum. The rest of the day is divided into two sections by the dinner, which performance is regularly and religiously attended to by every good bachelor.
The other sex of the bachelor is not yet discovered. There exists no female bachelor. Some biologists have supposed that the old maiden is a female bachelor in disguise. This is a dangerous and at the same time absurd error. There is a law of attraction, also called natural selection, pervading all sexual creation. But the bachelor, instead of being attracted, runs away from the old maiden; at the same time he proves by such action that with all her efforts she cannot be his natural mate. It is an error to consider the old maiden distinct from the species homo, because she would be the usual female of the species if she had
not been prevented to be so by circumstances over which she had no control ; so her development became arrested and she remained in a kind of larval state.
In the later part of his existence the bachelor becomes an uncle. There is still some mystery about the propagation of the bachelor. Some scientists pretend that he propagates by eggs, which he lays, like the cuckoo of Europe, in other birds' nests. Others have observed that he propagates by a biological process called generatio tequivoca. At any rate, may the process take the one form or the other, his offspring is called " nephew." Of this commodity he generally possesses only one, to whom he delivers moral lectures in the morning and pays the debts after dinner. And the accomplishment of these two objects is the task which fills the later part of his existence and for which he has been especially created, namely, paying the debts of his nephew and trying to improve morals which do not exist.
WHEN our most gracious Sire ordered me to enlighten you on the subject of love, he gave another proof of that giant intellect which is the admiration and astonishment of all who know him, for there are few people who have experimented on this subject so extensively as myself; and, as I have carefully concealed my profound knowledge, he must have learned my secret by that species of second-sight which belongs to a great genius.
As love is a matter of great antiquity and the discussion of it will occupy more than one evening, I have found it necessary to arrange it under three heads:
III. Love, from the point of moral philosophy, or, to express it in the elegant language of a prominent clergyman, "after jumping from crag to crag to the Alpine heights of vital existence, taking a bird's-eye view of moral responsibilities."
When we analyze the idea of love metaphysically, four possibilities present themselves to us: Love may be active, passive, reflective, or — and this is the most agreeable — reciprocal, which latter form is also called "mutual affection." To love actively and not to be loved is very distressing, but the passive without the active — that is, to be loved without being able to raise a corresponding affection — is even more awkward. The reflective form of love is the one most frequently found, for everybody loves himself tenderly and considers himself a nice fellow. I can even see in this congregation some members who rejoice in the reflection that they are lovely and charming.
Present love is easily explained ; in fact, under most circumstances we cannot understand how it is possible not to be in love. Past love is just the reverse — we cannot be made to understand how we ever could have been in love; and it is one of the most convincing proofs of the wisdom of an overruling Providence that, notwithstanding our desperate efforts, we never succeed in marrying our first love, who is most frequently a circus-rider, a milliner's girl, or the wax doll in the show-window of a hairdresser. If I had been compelled to marry all my first loves, I would have died by intermittent suicide. Past love, if not reciprocally past — that is, if the other party persists in being in love — may become very inconvenient, but I have found an effectual remedy, — namely, write to the lady the following letter: "Miss Brown, Smith, or Flanagan [never Nettie, Fannie, or Addie; that spoils the whole effect] : Do not try to explain; I know all." Now, you understand, there is ahvays something to know,
and a lady must be very hardened in love if after such a statement she seeks an interview. I intend to take out a patent on this prescription, which I call the Palaerotophylaktikon, and collect a royalty from all those who will use it; none genuine unless spelled with a K. Do not infringe on the patent, and beware of imitations.
Love from a physical point of view is not the exclusive property of mankind; it belongs to the whole organic world. Even plants love, and flowers communicate their feelings by winds and insects. Linnaeus founded his system of botany entirely on the relations between male and female flowers. Modern scientists have considered this very improper, and have introduced instead the words "pistillate" and "staminate," so that even the pistillate Bostonian may now study the science of flowers without blushing. Old Linne, in his blunt way, said: "The pollen is carried to the stigma by the agency of insects visiting for the sake of the nectar." Modern text-books let
us down gently, as follows: "The kisses of the staminate flower are carried to the reproductive organs of the pistillate flower on the purple wings of the butterfly, which for this service is offered a sip of nectar on the bosom of the latter." This is decidedly more aesthetic than the old version, but less intelligible; it is very chaste, but not quite true. In the animal kingdom we retain as yet the old expressions for sexual differences. We have even in regard to our own species kept the old suggestive pronouns he and she, and also in regard to animals of lower grade there is still great room for improvement. At present we say, for instance, a bull and a cow, and do not call the bull a staminate cow.
I now come to the third part of my lecture— the moral philosophy of love. The duties of social life oblige us occasionally to commit evening calls. On such occasions make it a point to call before eight o'clock. Scarcely have you touched the bell-handle, when the door is flung open
and in the entrance stands Bridget, smiling all over and with arms lifted for an embrace; but the smiles disappear, the uplifted arms sink down, and a moment later nothing is visible but a distant view of Bridget's indignant back, for you are not one of her numerous relations, and the pistillate Irishman expects a staminate cousin, not the purple-nosed butterfly which soars on golden wings to sip nectar and water on the bosom of the parlor table. Therefore, if you do not want to wait on the doorstep, ring the bell while the cousin is still expected. I consider it my sacred duty to correct here a dangerous error in regard to the moral philosophy of love. There exists a tradition, propagated from generation to generation, that there is an inverse ratio as to the callings of the heart and those of the stomach, or, to speak more plainly, that love diminishes the appetite. Now, my Bohemian brethren, there is perhaps not one amongst us who has not been thrown in profound admiration at seeing the object
of his heart's dearest hopes eat through the whole bill of fare at the Poodle Dog, from Baltimore oysters to cheese and black coffee. Love has but little influence over the organs of digestion. I have observed in a few cases (in friends) a momentary reduction in drinks; but whether their affection was accepted or blighted, the number of drinks very soon again reached a reasonable figure.
And now for the moral: Combine the physics and metaphysics, and never lose sight of the fact that the object of your affections possesses, besides a loving heart, a sound and active stomach.
THANKSGIVING DAY.
WHEN I first heard of the celebration of Thanksgiving Day I was seized with an irresistible desire to contribute to the festivities. Pondering over this subject, a thought struck me that a most appropriate exercise on such an occasion would be a botanical lecture; for such a lecture will not only produce in the time of its duration that state of somnolence called solemnity, but when finished give a lively feeling of satisfaction that can only be compared to the internal bliss felt by a pointer who has been whipped through a course of education and is conscious of the fact that there is a vacation of twenty-four hours till the next spinal irritation.
natural system, adopted by our most gracious Sire. The lecture will be contained in two parts. The first will be so scientific that none of you will understand it; the second, which is the most interesting, so profound that it is not understood by myself.
The pumpkin belongs to the natural order of Gucurbitacea, a family of doubtful affinities. According to the immortal Linnaeus, who invented the sexual system (for before him we all propagated by generatio cequivoca), the Cucurbitacece belong to the order Moncecia. This name is derived from monos, single, and oicos, house, and means two beds in one house — an arrangement somewhat favorable to matrimonial bliss.
The pumpkin also belongs to the Phanerogams, which propagate, according to a well-established law, without any mystery or secret relations. Not so the Cryptogams, whose ways are dark, arbitrary, and without the rule of an established law. They have different modes. The first of
them is by division, as, for instance, the bacteria; that is, an individual splits in two, each of the halves in a minute's time being ready for a new division. For example, if our most gracious Sire would adopt this method of propagation, in the time of five minutes this hall would contain thirty-two Sires, and in an hour the Pacific Coast would swarm with Sires, a circumstance that would benefit immensely the Bohemian Club, but would be a serious calamity to the medical profession.
It is not my intention to mention all the different methods of cryptogamic propagation, for I always have striven to protect the morals of our organization. I will only refer here to the higher Cryptogams, that are no more a mere compound of cells, but possess spiral vessels, vessels that open by a spiral corresponding to the spiral arrangement called by us "corkscrew." These plants possess alternating generations, an arrangement called dimorphisms, from two Greek words — di, double, and
morphy, which means an Irishman; for all great scientific discoveries have been made by the Irish nation, with the sole exception of the conifers, which were discovered by the conic section of the Hebrew race. In regard to the systematical position of the pumpkin, I think the place assigned to it by our most gracious Sire is the most honorable it can ever occupy.
ON TRUTH.
THE real Queen of Bohemia is Truth. She is worshiped by our literati, admired by our penny-a-liners, imitated by our artists, and praised by me. Yes, Truth has the great prerogative to be praised by me, for my specialty is morals.
On previous occasions I have lectured on Virtue. My success was greater than desirable. With some friends the progress on the path of virtue was too rapid, according to my taste — some short-winded members of the congregation that wanted to keep up with the race and could not have seriously injured their constitutions. But if our worthy Sire will take all responsibility on his own venerable head, I am ready to cause another stampede; only I will use the precaution to discuss Virtue not in her
form Virtue is less dangerous.
The object of our present contemplation is the beauties of Truth. Truth, also called veracity, in spelling matches sometimes voracity, which means another virtue, was called Veritas by the Romans, and was worshiped in a temple near the Via Appia. This temple does not front the street. Truth frequently is hidden. The entrance to the temple of Truth is through an adjacent saloon, from which circumstance the Latin saying, In vino veritas, derives its origin. Once I had to see a friend in this saloon. By some queer coincidence all my friends develop a most remarkable thirst for Truth. On this occasion I was introduced to the high priest of the goddess, who, after having bestowed his blessing and distributed spiritual comfort all around him, invited me to a private revival in the innermost recesses of the sanctuary. Here Truth stood on a pedestal,
without any other garment but a lookingglass in her hand. "Is this Carrara marble?" I asked the holy man. "No," he said, "it is papier-mache, and hollow inside; but does she not look like Carrara marble?" " This statue," the holy man continued, "has been created at a great expense by the great Greek sculptor Phidias, after a photograph taken by our special artist, Bradley Rulofson. There was but little difficulty for the sculptor, but a world of trouble for the photographer. I never have seen a deity so particular about retouching. This peculiarity, and the circumstance of her eyes being so intensely fixed on that looking-glass, is probably the reason why the Romans consider Truth a female deity. No male deity could fix his eyes for such a length of time on a looking-glass, not even when shaving. It probably has not escaped your experienced eye that Truth is naked. Now, to you and me that matters very little ; many a time we have seen and have heard naked Truth; but we have to con-
sider that ladies, although but rarely, worship in this temple. We therefore every morning dress Truth after the latest fashion, the garments being made out of the daily papers. It now devolves upon me to take your oath that you will never divulge, always conceal, and never reveal anything that you have seen or heard in this sanctuary."
With these words the holy man produced a copy of Baron Miinchhausen's Travels. I kissed the sacred book and swore a Custom-House oath that I will remember to the end of my days. But, as we are here amongst friends whose capacity to keep secrets is proverbial, I will tell you all about it:
Truth has very little charms ; all my lady acquaintances are much prettier. Truth is plain, and, strange to say, she calls herself frequently plain Truth. But she does not mean it.
Search for Truth; and when you have found her, keep her for yourselves. When compelled to part with her, dress her up pleasantly and after the day's fashion, and never throw that pearl to your husbands.
real cause of the long dilation was an indecision on my part about the method of my travel. It would have been against my principle to travel by railroad, because under no condition would I encourage the heartless monopoly of the Central Pacific Railroad; besides, I have of late constantly been out of cash and had not the funds necessary to buy my ticket. So I decided to swim the Golden Gate, and found, when I landed
near Fort Point, a military deputation ready for my reception. They had left their muskets home, which was very considerate of them. They knew that since my good grandmother was killed by an accident with firearms my nervous system has become very susceptible, and I do not like to hear shooting.
Unprepared as I was, I was nevertheless up to the occasion, and was just beginning a speech, when they retired rather hastily; probably because they saw that I was exhausted by the long swim and the exposure of my system to undiluted water, and that again was very considerate of them.
I found the country very much changed since my last visit. On my way to the city I met a police force that evidently was not so friendly disposed as the military deputation who received me when I came out of the water. Never-
ways have been a good citizen. Not for the world would I have resisted an arrest made by a superior, well-armed force, as long as I was sober. But I was spared the ignominy of a public arrest by the intervention of an Italian bootblack. Scarce had the men of the law seen the bootblack unpacking his box on the margin of a sand-lot, when they turned from me and arrested the Italian for blocking up the sidewalk. I was very much pleased with the promptness of this action, for I always liked to see authorities doing their duty, and that bootblack had no right to be a bootblack. Why was he not a dry-goods merchant, and he could have placed as many boxes on the sidewalk as he thought fit; or that auctioneer on California Street, about whose fragrant audience you complained in your last letter as blocking up the road to the Academy of Sciences?
You know that I always longed for a position in a zoological garden. In looking round for an institution of this kind to be
whose ornament I would condescend, I met a troop of men in common citizens' garb, but each of them walking behind a rifle pointed at my head. As I was certain that these men would not fire so long as I was near, I accosted them and entered into a conversation. They were very pleasant, but told me there was neither a zoological nor a botanical garden in existence, but plenty of beer-gardens and lunch saloons; there was somewhere over the water a kind of scientific institution, but I never could be admitted there, as I was not born in Massachusetts. Soon after I had thanked them for their kindness and taken leave, I heard several shots and saw four big holes fired into nature. In order to avoid an accident, I withdrew into the chaparral, took a hasty breakfast at an Italian gardener's, borrowed a dish of veal from a French stockraiser, and retired for the sake of my health into the wilderness around Uncle Tom's Cabin, where the great number of Sunday hunters have created a climate so salubrious that
old age. Yours truly,
P. S. There has been a report in the San Francisco newspapers that I was killed. Don't believe it. It is an old trick. When the California Legislature in the year '52 put a price on the head of Joaquin Murieta, three heads of said Joaquin were handed in and paid for; and as Joaquin is still alive, it is impossible to form an idea of how many heads he could have furnished since then, if the payment had not been stopped. The old Californians are not so easily killed.
THE MICROSCOPE.
THE microscope is an implement composed of glass and brass. The brass is used in two different preparations, — first, in its purely metallic shape; secondly, in the shape of a brass band, which serves to make microscopical demonstrations more intelligible and prevents conversation with a lady neighbor. Brass was discovered in the age of bronze by a gentleman named Tubalcain. Particulars can be found in the sacred records of the Patent Office at Washington, where his name is mentioned in reference to a new process.
Glass was discovered by a Phoenician Superintendent of Public Streets, who spent considerable time in experiments to find for public improvements a sufficiently destruc-
tible and at the same time expensive substance. Modern science has provided our Superintendents of Streets with a series of more pliable, brittle, and costly bodies; but still in more sequestered localities traces of the pavement may be found that was characteristic to the age of brass. The name of this Superintendent of Streets was Flanagan Abu Baker ben Snodgrass, who was born at Sodom and Gomorrah, under the reign of the Egyptian king, Pharaoh Meyer.
It is a most melancholy fact that the great man after having discovered glass made a too free use of glasses. The police records of Tyrus, Sidon, Antiocha, and Damascus show his name on every page, and the station-house of Jerusalem exhibits still his curious and interesting autograph. On a stormy night, when he was camping out at the station-house of Tyrus, rattlesnakes got in his boots, and when he awoke next morning he found he was dead. So this man shared the fate of all discoverers; he bene-
died himself.
There is no invention that has had the same influence on spiritual as well as on material welfare of mankind. Before glass came into use no looking-glass ornamented the walls of sleeping apartments. The consequence was that the ladies could not dress, for young ladies cannot dress without seeing their faces ; they had to repair in deep undress — in fact, barefoot to a great extent — to the next river, lake, brook, or streamlet, by which act they did hurt sorely every morning the feelings of all the old maidens and shocked very much the whole male population, who, by some unaccountable coincidence, collected at the same hour in the same locality.
But glass is also a bulwark of free institutions. Some thirty years ago, when I visited the Continent to barter for an honorable degree at Giessen, I went out on a clear night to study astronomy with the assistance of some glasses obtainable at a
saloon round the corner. Dark shades on one side of the street, the other side illuminated by the pale spectral light of the full moon, which stood high over the steeple of the old Gothic church. Here I stood on a Miocene formation, surrounded by playful trilobites, on the very spot where the highway of wandering nations is crossed by some meridian. I sank into deep revery. I saw the eagle on the helmet of the Gothic chief. I saw the dark, heavy Burgundian on his way to Barbary Coast. At this moment my revery was interrupted by the harmonic sound of broken windows. The free and independent descendants of the same Goths and Vandals manifested their political antipathies by breaking the windows of the resident officer of the Government, and they broke the windows of all the inhabitants of the town. By this delicate and judicious proceeding they promoted at the same time political progress and domestic happiness.
of the bottle.
Now, after having discussed how much humanity has been benefited by brass and glass, the component parts of the microscope, you may judge for yourself how deeply mankind is indebted to the microscope itself.
IN THE NAME OF THE PROPHET.
THE text of our present contemplation is found in our sacred book, the Koran, where it is contained in the impressive words, "Kullu meskirin haram." As I have observed that some of you have become rather rusty in your Arabic, I will translate it for you. It means, All intoxicating things are forbidden. There are some heretics who read "hammam" instead of "haram," so that the passage would be "Kullu meskirin hammam," which would mean, All intoxicating drinks must be hot. May the hereafter of such heretics be hot!
Now, let us inquire why our holy prophet Mohammed — blessed be his name! — pronounced these hard and apparently cruel words. On former occasions I have incul-
cated into your minds the important truth that a symmetrical development in vice leads to a blessed life in the terrestrial existence as well as in our hereafter. I know by my own experience how difficult it is to practice several vices successfully at the same time. Our great prophet, therefore — • blessed be his name! — has arranged matters in a way that we derive almost the same spiritual benefit by practicing them one after the other. As I have done on former occasions, I will give you the benefit of my own experience.
I began my moral career by stealing apples. Then I practiced polygamy — or rather tried to practice it. Then I cultivated friendship in an alcoholic solution, and here I place myself before you and ask, What next? Now, you will recollect that the rights of individuals are limited by the rights of the nation, and, vice versa, the rights of the nation begin where the privileges of the individual end. This is exactly the case in regard to the order in which
the different vices have to be practiced; it begins in the human race where it ends in the individual. Full of vital vigor, nations step on the stage of history and ask, What next? Next they take to strong drink combined with friendship, then they introduce polygamy, and end where I began — by stealing apples.
At the time when our great prophet — blessed be his name! — preached to the nations, all Asia Minor, from the straits of Bab el Mandeb to the ports of the Caucasus, was drunk before ten o'clock in the morning. What says the great Ibrahim ben Bamboozel Abu Beker ben Smith? No true believer is expected to be drunk before eleven o'clock A. M.
Our great prophet saw immediately that the next vice was in order, which was, under the circumstances, polygamy. So, my dear brethren, let us follow the teachings of our prophet — praised be his name! — let us stop drinking and let us practice polygamy. If the laws of the country prevent us from
IT was not my original intention to inflict this lecture on you. You have to blame our most gracious Sire for it, who insisted on my lecturing to-night, and threatened, in case of disobedience, to take my place, as he has done at former occasions. To save you from such a calamity, I have complied with his wishes, and here I stand a victim of illdirected sense of duty.
My Bohemian brethren, if you consider that the day which we celebrate to-night, or the night which we celebrate to-day, is its 1 887th anniversary, you must comprehend the difficulty of saying anything that has not been said before. It is my custom under such circumstances to consult my spiritual adviser — Rev. George Bromley — to whom
" You speak about five minutes," the pious man answered; but noticing the melancholy expression that imparts a peculiar charm to my features, he called me back and addressed to me the following words of wisdom:
"You fool,- — that is to say, my son, — read to us one of the papers which you have read before at the meetings of the California Academy of Sciences. Nobody will notice the difference, and besides you are bound in justice to do so, as we have well noticed how frequently, under the disguise of profound science, you have inflicted papers belonging to this Bohemian forum upon our unsuspecting sister organization."
These were the words of the pious man, and I went immediately to the hall where I keep my manuscripts, took a drink, and selected from the treatises on trees one on the Christmas-tree and its botanical and
berry jelly.
The Christmas-tree belongs to the conifers,— that is, trees which bear cones. But it is not always that they bear cones; some of the members present will convince themselves to-night that this wonderful tree has the power to bear fruit of the most surprising kind and character. The leaves of the tree are everlasting, or evergreen, which is the symbol of persistent innocence, and not intended as a satire or allusion to the amount of innocence accumulated by the younger members. The stem is not green, but nevertheless everlasting, as it will sprout out after every forest fire, and even escape the dangers of the "State Commission for the Preservation of Forests."
After the new year the tree can no more be used, for then the season approaches when our forests are vaccinated, to protect them against phylloxera and rinderpest. In spring it produces flowers, in summer picnics, and ripens its fruit at Christmas.
Its chief occupation is to attend at forest fires. In its leisure hours it protects the springs whose waters we dilute with whisky; it also shades the tributaries of our water-works, whose contents assist and contribute so largely to our collection of microscopic animals. The same tree protects at our Midsummer High Jinks the wise and venerable head of the old Bohemian and imparts a beautiful green bloom of persistent innocence to the intelligent face of the Bohemian neophyte.
So, dear Bohemian brethren, let us do homage and bow to-night reverently before the tree that shelters our midsummer services and enlightens and illuminates the present celebration.
A CELEBRATION like that of to-day has always a tendency to recall the past. It makes us look back into our own bygone days and also into the past ages of our race. So let us then date back the present night for a millennium and a half, and let us imagine that we live at the time when Constantine the Great ruled at Byzantium. We are not Bohemians to-night; we are northern barbarians— Waraegians that fight as mercenary soldiers for the Roman Emperor, Danes that plunder the northern coasts, Normans that invade the Mediterranean — and led by our chieftains Hengist and Horsa, Angular Saxons, who found corner groceries.
The banquet of to-day is not called Christmas; its name is Yule. On the fireplace flames the yule-log, the sacred emblem of the god Balder's death. Champions
and warriors, seated on benches, occupy two sides of a long table. On an elevated seat at the head of the table presides the bold Jarl. The whole resembles a low jinks. On the walls lean torch-bearing serfs, instead of gas flames measured by cubic feet. Horns of the Urus filled with mead go from hand to hand, and the heroes walk up where the head of a wild boar is placed before the throne of the powerful Jarl.
This hall forms part of an ancient tower rising on a cliff that overhangs the wild waves of the German Ocean, not the California Market. Looking down from the stormy height, you witness the eternal warfare waged between rock and wave. The foot of the cliff is surrounded by phosphorescent breakers like this block by the fiery brokers. On the head of the wild boar the warriors lay their hands and pronounce vows according to ancient rites. In solemn chorus they sing:
The impressive ceremony is interrupted by the discordant sound of a horn. "Is that the Gjallarhorn," exclaims the bold Jarl, "that invited us to Valhalla? Or is it the toothorn of the festive hoodlum?" The door of the hall is flung open, an icy blast of the snowstorm enters.
" In Balder's name, shut that door," orders the Jarl; "even the San Francisco Morning Call would declare that weather more than partly cloudy. It is enough to give rheumatism to a rhinoceros, and at present I am oscillating between the regular school and homoeopathy, since I found out that the same liquid that cures the bite of the rattlesnake has the power to produce the same reptile in the boots, as I am convinced by my own experience."
Then a rumbling and clanking noise is heard as if a tinshop was tumbling down a flight of stairs, and in steps Viking Bromley the Terrible in full armor.
"The bold Jarl will excuse me. I took a vessel near the Straits of Gibraltar loaded with wine from the island of Cyprus. My men are bringing the casks."
Hearing these words, Hero Damm spits his mead secretly on the floor, Burke Thirstenson empties his horn hastily into his throat; both are ready for Cyprus.
And a pair of Greek maidens, fair as the day, dance gracefully into the hall, wreaths in their hair and garlands in their hands. They look very much like brothers Belknap and Swan. Standing on one leg, they spread gracefully their arms and sing an ode of Anacreon on forensic medicine.
And Bear the Virtuous, well versed in ancient lore and of venerable appearance, walks up to the elevated seat and sings before the Jarl a beautiful song of Hagbart and fair Signe, and how Signe followed her lord and master to the funeral pyre, where she was burned with all her treasures and the gold of her teeth, filled by Dr. Younger, and her library of dry-goods bills ; and then he sings into the golden strings of his harp of ancient times, and how Christmas was celebrated with our glorious ancestors ; and then he puts his harp into his coat pocket, walks gracefully up to the Jarl, and asks for a drink.
WHEN I received a notice from our most gracious Sire that he expected me to make some appropriate remarks on Ideal Bohemia, I immediately began to ponder on the beauties of Bohemia, the high objects of its organization, and the inscrutable wisdom of our most gracious Sire in having appointed me to lecture on such an exalted subject. From pondering over this subject, my mind soon fell to wandering, a habit to which I incline more or less after nine o'clock P. M., and roamed through the vast realms of other memorable things. I made some exceedingly valuable discoveries. Experience has shown me the lamentable fate of all my discoveries made after nine o'clock P. M. — I do not recollect them the
following morning. Therefore, this time I reduced the result of my philosophical researches to writing, and I am here to enlighten you on inscrutable things in general and the different species of inscrutable wisdom in particular.
Amongst inscrutable things there are three that have occupied the human mind in all ages. It is immensity of time, also called "Eternity"; immensity of space, or the "Universe" ; and, thirdly, the boundary line between necessity and free will.
Of the immensity of time anybody can form an idea who enters a dentist's office and finds there a notice: "Doctor back in five minutes." These five minutes are an immensity of time.
As to immensity of space, a San Francisco horse-car is a good illustration — a universe that has room for another universe and plenty of room on the top.
As to the boundary-line between capacity and free drinks, its limitation is found by multiplying capacity by the figure of ready
cash, and then adding the credit strained to its utmost extent in regard to time and place. The most useful of inscrutable things is the inscrutable wisdom of Divine Providence, which is indispensable to the daily press. For example: It has pleased the inscrutable wisdom of Divine Providence to take from our midst our dearly beloved mother-in-law, Barbara Scoldum. Now, there is something incomprehensible at first look in this action of inscrutable wisdom. Divine Providence in taking that particular mother-in-law will soon find that he has caught a tartar. But, in carefully studying up the case, we will find that inscrutable wisdom keeps a place in some distant part of its premises where all the good mothersin-law go, which place will be considerably warmed up immediately after the arrival of mothers-in-law. There is an arrangement that as soon as the thermometer of that place sinks below the temperature of Fort Yuma a mother-in-law is introduced to save fuel. The natural philosopher calls this ar-
rangement economy of nature. The heated term by which we were visited a fortnight ago was caused by an accumulation of mothers-in-law who had to remain in the sphere of our planet until accommodations would be provided for them in the place of their destination.
Sometimes it is a difficult task to investigate the intentions of inscrutable wisdom; for instance, the use of the heads of some of our City Fathers. Their heads are neither useful nor ornamental; they are not made for brainwork. We can prove, by a post mortem, to their owners7 own satisfaction that their heads are empty. But they serve a higher purpose ; they keep the necktie in its proper position.
The coast of California has passed through violent convulsions and cataclysms. Since the glacial period the coast has been submerged and raised to Alpine elevations. There is no mining stock that has passed through such vicissitudes of ups and downs as the hills and plains of California. Bi-
valves and remains of marine crustaceans have been found on the tops of the Sierras, and an empty sardine-box has been discovered by me in the picturesque wildernesses of Second-Street cut, which may be inspected at the rooms of our Academy of Sciences.
To protect us against further disturbances of level, against tidal waves and sudden upheavals, inscrutable wisdom of Divine Providence has created Captain Kenzel, who keeps the coast line of the Pacific in its present position.
Now, everything would be smooth and Divine Providence all right if it were not for the California Legislature that runs a biennial opposition line to inscrutable wisdom. But even with this defect, this world is a good world, and even our most gracious Sire, with the assistance of all the members of the Sideboard Committee, could not have created a better one.
ON EVOLUTION.
THE source of all organic life is the cell. From the simple cell, which constitutes the monad in the animal kingdom and the bacillus in the series of vegetable developments, branch off innumerable evolutionary series of types.
and other rational enjoyments.
The change of types which I am here to demonstrate begins in the post-pliocene age. The post-pliocene age we divide first in the age of stone implements, which is followed by the age of brass. In this age mankind got very degenerate in morals, so that, for the sake of their transgressions, a Board of Supervisors was set over them. No sooner was this board in power, when an extension was proposed of the Libyan and Arabian desert and passed. Then the Mississippi River was forced to run through the FifthStreet sewer, which sewer was repaired in the middle of the rainy season. This caused a great flood, and the term antediluvian, which we use in the Academy of Sciences, refers to the time before that event. The flood caused the age of brass, after which followed the age of iron, and at present we are in the middle of the age of steel.
organisms during these long periods can easily be followed from the gray dawn of antediluvian existence up to their present perfect organization.
When we, for instance, remember the well-known fact of a post-pliocene grasshopper developing by natural selection in the course of ages into a race-horse, we will no longer be astonished when by popular election a clodhopper develops into a regent of a university. A prominent clergyman, combining by natural selection Darwinism and sacred history, has called this law, in a popular lecture, " inverted comic action" — or was it conic action? — "of irradiating ether." Here are a few examples :
You see how an antediluvian snail has been transformed into the inkstand of the present age, a circumstance which accounts, perhaps, for the extraordinary laziness of
Here you see a dinotherium :
He looks very much like the African hippopotamus, but his African sympathies are not real. In his present stage of development he is born in the north, but feeds in the south.
Now, reflecting on these facts and looking forward into the past of antediluvian times, we find everywhere the footprints of the finger of a mighty creative power.
ONE of the most powerful inventions of the nineteenth century is the germ theory. The germ, also called microbe, leads in its wild state a migratory life, — that is, he is always found where he ought not to be; afterwards he takes to different liquids and becomes cultivated. In this circumstance the microbe resembles some young men who are shiftless and spend their school hours by being found where they ought not to be, and then take different liquors. Such young men never will pass their examination and they will not graduate, but become members of the Board of Education or book agents, and will have to recite in their old age lessons on the germ theory.
monial relations.
First, the microbe as an organism appears in different forms, which have received different names: bacterium, bacillus, vibrio, spirillum, and many others ; all of which I knew this morning, and with which Miss Allbustle, who is our principal, is perfectly acquainted and on terms of intimacy. All these organisms agree on one point — they gobble up all oxygen on which they can lay hand and make it hot for the neighborhood which Miss Allbustle calls "Surrounding medium." By this process, in a way perfectly known to Miss Allbustle, they cause fermentation and inflict incalculable misery on the human race; because, if there were no fermentation, there would not be intoxicating drinks ; if there were no intoxicating
be sin.
I now come to the microbe as a fellowcitizen. As such the microbe is exceedingly useful to the medical profession, the drugstore, and the sale of microscopes. He can raise an epidemic on a moment's notice, and is cultivated for this purpose either in gelatine or beef-tea. Whenever the state of a community becomes melancholily healthy, the same cultivated and well-trained bacteria are let loose on the community, and our doctors and the sister of Miss Allbustle, who is a female medical man, have more business on hand than they can attend to. Formerly, before the microbe became educated and cultivated, and was examined, and had to graduate as a microbe, the doctors had to go to the mountains to lasso some wild bacteria, which is a dangerous enterprise. Some bacteria have a spiral shape, somewhat like a snake or a corkscrew. They derive their name, "spirillum," either from
Thirdly, the microbe in his or her matrimonial relations : The microbe is not very affectionate. He can be tamed and made to follow his master, but he never, never will love you. He propagates by separation pretty much as they do in Indiana. So he multiplies by division, and in producing several individuals he loses his own individuality.
ADDRESS TO THE MAYOR.
THIS time I am not taken by surprise. I know I am always called for late at night, like the loose troops that cover the retreat of the really valuable army; and as it is a great strain on my nerves to keep sober a whole evening, I have committed my ideas to paper, and this is my extempore speech.
This city, inhabited by honest, hard-drinking men, has many grievances. Our pavement, for instance, is of great importance. Climate and habits dispose us to gout. You recollect Dr. Arthur Stout, the inveterate
punster of this organization. He frequently said, "Chaqu'un a son gout." Pavement is of great consequence to elderly gentlemen. It always touches my heart to see a friend, when crossing the street, how carefully he treats the cobblestones of our pavements. Public property must be treated with consideration.
Now, there is a place whose access is paved by good intentions. Why not use the same material for paving this good city? I own the material is rather friable, but there is such a supply of it, and our City Fathers are on such excellent terms with the owner of that place, that they may get the material at a nominal expense.
In the hope that you will follow this disinterested suggestion, I am convinced that a man who has filled the presidential chair of this important organization will find it an easy task to rule an insignificant city like San Francisco.
3d. Spiritual advice.
According to the generally adopted definition, a fish is a vertebrate animal that breathes through gills. Everybody sees that this is a very superficial definition ; for we have not time always to look for a spinal column, and as for the gills, they are generally removed by the cook.
My definition is : A fish is an aquatic animal without feet and without hair. Somebody might say this definition will embrace also the snake ; but the snake is amphibious, — he can live both in the water and in the boots.
The fish is essentially without hair. Fish's hair-oil has been tried at different times by several members of our Academy of Sciences on their own heads, without producing anything like the desired effect.
The fish has no feet, which circumstance saves him a world of trouble; having no feet, he has no big toe; having no big toe, he has no gout; having no gout, he is not suffering from the pavements of this good city.
I had invited a good friend to assist at this symposium; I am sorry to say that he was prevented by an attack of his old enemy, the gout.
This good friend has suggested at different times a method how to improve the pavement of San Francisco for the benefit of the gouty members of this community, who represent a considerable proportion, and at the same time to settle that most vexing question about asphalt, basalt, and Nicholson.
paved by good intentions. As our public officers always have been on excellent terms with the owner of that place, they easily could obtain the material at a nominal price.
We all know with what facility the material is to be manipulated; it is true it has no great power of resistance and will want frequent repairs, but then there is such an enormous supply of it.
In regard to the classification of fishes: We have an artificial system and a natural system. The artificial system takes up a single character for classification, but the natural system compares carefully all the characters, and judges from the totality in which style the fish ought to be served. Aquatic as their habits may be, all good fishes when cooked are served with white wine, and this is in the animal kingdom the first instance of the better hereafter that awaits us.
and those with a cartilaginous skeleton. In the first group belongs the eel, which is the only hermaphrodite amongst vertebrates. I know this is very immoral, but it is arranged so by Nature, and I am ashamed of Nature. Not so the eel ; he leads a life of permanent matrimonial bliss, interrupted only by an annual marriage trip to the sea coast, where, after having propagated, he leaves his offspring to the benevolent attentions of sharks and other fishes. At a moment's notice he withdraws to places inaccessible to his creditors. Amongst the fishes with a cartilaginous skeleton, the most remarkable is the sturgeon, whose eggs are called caviar, and here comes my spiritual advice. Never! never mistake caviar for blackberry jam!
ON BUTTERFLIES.
IT is impossible for me to tell anything new to this enlightened body of Bohemians, because everything that was in me has been brought out on former occasions, and what little brain is left I want for myself. But noticing here the presence of Dr. Swan and Judge Boalt, my old rivals in science, I am afraid they will trespass on the sacred ground of entomology, as they have done before ; and so, for the protection of science, I will sacrifice myself, as I have done before, and occupy your valuable time with a lecture on butterflies.
The butterfly lays eggs like the hen, but differs from the hen by laying her eggs but once in her lifetime. From the egg comes a caterpillar, or, as Judge Boalt justly observed, a worm. The whole occupation of
this worm consists in eating. His whole existence is a prolonged dinner-party. Several times he changes his dress by bursting it on his back and throwing it off, a new, well-fitting, unpaid dress being already underneath. When entirely satisfied he goes to sleep, calls himself a chrysalis, and awakes as a butterfly. This new existence begins with making love all around and gaining the mutual admiration of both sexes. Then he takes to morals, matrimony, and a wedding trip ; after which he dies, before making the acquaintance of his mother-in-law. In the stage of butterfly he dispenses entirely with solid food and relies altogether on liquid substances, which he calls nectar and we call drink. Now, you see his first stage of existence is a continuous dinnerparty; then comes a period of digestion and rest, after which a system of free love and drink all around; but in no stage work, if he can help it.
spects, it is not difficult to distinguish him. The butterfly leads an aerial life ; the oyster lives on the bosom of the ocean, in localities inaccessible to his creditors. Most species of the oyster are hermaphroditic — they possess both kinds of sexual organs. Therefore, the oyster enjoys the rapture of the lover and of the beloved, and thus on the bosom of the ocean (which is at the same time the bottom of the ocean) he enjoys a life of uninterrupted matrimonial bliss. But, besides this blessing, the oyster is entitled to the proud distinction of being present at all banquets given by the Bohemian Club; and I am charged by the oyster to express on this occasion his thanks for the honor of his invitation and his wish that such invitation may be extended to him at all further celebrations, and especially our Golden Anniversary, when, twenty-five years hence, he hopes to meet you all again.
| 33,810 | common-pile/pre_1929_books_filtered | hootofowl00behrrich | public_library | public_library_1929_dolma-0015.json.gz:3303 | https://archive.org/download/hootofowl00behrrich/hootofowl00behrrich_djvu.txt |
IR7zvz_GN-UVyow6 | Post-Secondary Peer Support Training Curriculum | The Power of a Hopeful Response to Suicidal Ideation
When someone we’re working with shares that they are contemplating suicide, it is important that we choose hope-based rather than fear-based responses. When we respond from fear, we react based on what we’re afraid might happen or what we think might be wrong. When we respond from hope, we respond based on what we believe is possible and with hope for co-creating something new.
The following chart is shared from Shery Mead’s Intentional Peer Support work and highlights the difference between a Hope Response (what we refer to above as a hopeful response) and a Fear Response (fear-based response) when supporting someone who expresses suicidal ideation:
| Hope Response | Fear Response |
|---|---|
| Sitting with the discomfort of the situation | Trying to calm things down: stabilization |
| Staying connected to the person | Taking care of, helper/helpee |
| Unpredictability = Possibility | Predictability: things go back to the way they were. |
Some Things to Remember
When supporting someone who is contemplating suicide, keep the following in mind:
- Remind them that they are not alone
- Express your care and concern for them–however, don’t say anything you don’t mean, as that could be triggering
- Ask them about people they care about
- Practice empathy, but don’t say anything like “I know exactly how you feel.” You don’t know exactly how they feel, even though you may have experiences something similar
- If you have felt similar things you can say, “I’ve struggled with thoughts of wanting to escape or die too.” This might help them to feel less alone. However, be cautious to not make the conversation all about you. Stay focused on them.
- If you haven’t experienced thoughts of suicide, consider saying something like, “I can sense how desperate you are from your voice.
- Don’t try to fix their problems–just listen
- Be aware of your judgements and your worldview, practice putting your judgements aside
- When the person is safe and you are able to leave, seek support for yourself. Speak to your supervisor or a counsellor at your school about your feelings. It is very important that you debrief with someone for your own well-being. | 488 | common-pile/pressbooks_filtered | https://opentextbc.ca/peersupport/chapter/the-power-of-a-hopeful-response-to-suicidal-ideation/ | pressbooks | pressbooks-0000.json.gz:53775 | https://opentextbc.ca/peersupport/chapter/the-power-of-a-hopeful-response-to-suicidal-ideation/ |
TRIJdBWo9ew7C05Q | 4.1b: Constant coefficient second order linear ODEs | 4.1b: Constant coefficient second order linear ODEs
Solving Constant Coefficient Equations
Suppose we have the problem
\[ y'' - 6y' + 8y = 0, y(0) = -2, y'(0) = 6 \nonumber \]
This is a second order linear homogeneous equation with constant coefficients. Constant coefficients means that the functions in front of \( y''\), \(y'\), and \(y\) are constants and do not depend on \(x\).
To guess a solution, think of a function that you know stays essentially the same when we differentiate it, so that we can take the function and its derivatives, add some multiples of these together, and end up with zero.
Let us try \(^{1}\) a solution of the form \(y = e^{rx}\). Then \(y' = re^{rx}\) and \(y'' = r^2e^{rx}\). Plug in to get
\[\begin{align}\begin{aligned} y''-6y'+8y & = 0 , \\ \underbrace{r^2 e^{rx}}_{y''} -6 \underbrace{r e^{rx}}_{y'}+8 \underbrace{e^{rx}}_{y} & = 0 , \\ r^2 -6 r +8 & = 0 \qquad \text{(divide through by } e^{rx} \text{)},\\ (r-2)(r-4) & = 0 .\end{aligned}\end{align} \nonumber \]
Hence, if \(r = 2\) or \(r = 4\), then \(e^{rx}\) is a solution. So let \(y_1 = e^{2x} \) and \(y_2 = e^{4x}\).
Check that \(y_1\) and \(y_2\) are solutions.
Solution
The functions \(e^{2x}\) and \(e^{4x}\) are linearly independent. If they were not linearly independent we could write \(e^{4x} = Ce^{2x}\) for some constant \(C\), implying that \(e^{2x} = C\)for all \(x\), which is clearly not possible. Hence, we can write the general solution as
\[ y = C_1e^{2x} + C_2e^{4x} \nonumber \]
We need to solve for \(C_1\) and \(C_2\). To apply the initial conditions we first find \( y' = 2C_1e^{2x} + 4C_2e^{4x}\). We plug in \(x = 0\) and solve.
\[\begin{align}\begin{aligned} -2 &= y(0) = C_1 + C_2 \\ 6 &= y'(0) = 2C_1 + 4C_2 \end{aligned}\end{align} \nonumber \]
Either apply some matrix algebra, or just solve these by high school math. For example, divide the second equation by 2 to obtain \(3 = C_1 + 2C_2\), and subtract the two equations to get \(5 = C_2\). Then \(C_1 = -7\) as \(-2 = C_1 + 5 \). Hence, the solution we are looking for is
\[ y = -7e^{2x} + 5e^{4x} \nonumber \]
Let us generalize this example into a method. Suppose that we have an equation
\[ \label{eq:6}ay'' +by' +cy = 0, \]
where \( a, b, c \) are constants. Try the solution \( y = e^{rx} \) to obtain
\[ ar^2 e^{rx} + bre^{rx} + ce^{rx} = 0 \nonumber \]
Divide by \(e^{rx}\) to obtain the so-called characteristic equation of the ODE:
\[ ar^2 + br + c = 0 \nonumber \]
Solve for the \(r\) by using the quadratic formula.
\[ r_1, r_2 = \dfrac {-b \pm \sqrt {b^2 - 4ac}}{2a} \nonumber \]
Therefore, we have \(e^{r_1x}\) and \(e^{r_2x}\) as solutions. There is still a difficulty if \(r_1 = r_2 \), but it is not hard to overcome.
Suppose that \(r_1\) and \(r_2\) are the roots of the characteristic equation.
If \( r_1\) and \(r_2\) are distinct and real (when \( b^2 - 4ac > 0 \) ), then \(\eqref{eq:6}\) has the general solution
\[ y = C_1e^{r_1x} + C_2e^{r_2x} \nonumber \]
If \(r_1 = r_2 \) (happens when \( b^2 - 4ac = 0 \) ), then \(\eqref{eq:6}\) has the general solution
\[ y = (C_1 + C_2x)e^{r_1x} \nonumber \]
For another example of the first case, take the equation \(y'' - k^2y = 0 \). Here the characteristic equation is \( r^2 - k^2 = 0 \) or \( (r - k)(r + k) = 0 \). Consequently, \(e^{-kx} \) and \(e^{kx} \) are the two linearly independent solutions.
Below is a video on the characteristic equation of a differential equation.
Solve
\[y''-k^{2}y=0. \nonumber \]
Solution
The characteristic equation is \(r^{2}-k^{2}=0\) or \((r-k)(r+k)=0\). Consequently, \(e^{-kx}\) and \(e^{kx}\) are the two linearly independent solutions, and the general solution is \[y=C_{1}e^{kx}+C_{2}e_{-kx}. \nonumber \]
Since \(\cosh s=\frac{e^{s}+e^{-s}}{2}\) and \(\sinh s=\frac{e^{s}-e^{-s}}{2}\), we can also write the general solution as \[y=D_{1}\cosh (kx)+D_{2}\sinh (kx). \nonumber \]
Below is a video on finding the finding the general solution to a differential equation.
Find the general solution of \[ y'' - 8y' + 16y = 0 \nonumber \]
Solution
The characteristic equation is \( r^2 - 8r + 16 = {( r - 4)}^2 = 0 \). The equation has a double root \( r_1 = r_2 = 4 \). The general solution is, therefore,
\[ y = (C_1 + C_2x)e^{4x} = C_1e^{4x} + C_2xe^{4x} \nonumber \]
Below is a video on finding the general solution to a differential equation involving two real irrational roots.
Check that \( e^{4x} \) and \( xe^{4x}\) are linearly independent.
- Answer
-
That \( e^{4x} \) solves the equation is clear. If \( xe^{4x}\) solves the equation, then we know we are done. Let us compute \( y' = e^{4x} + 4xe^{4x} \) and \( y'' = 8e^{4x} + 16xe^{4x} \). Plug in
\[ y'' - 8y' + 16y = 8e^{4x} + 16xe^{4x} - 8(e^{4x} + 4xe^{4x} ) + 16xe^{4x} = 0 \nonumber \]
We should note that in practice, doubled root rarely happens. If coefficients are picked truly randomly we are very unlikely to get a doubled root.
Below is a video on finding the the general solution to a differential equation.
Let us give a short proof for why the solution \(xe^{rx}\) works when the root is doubled. This case is really a limiting case of when the two roots are distinct and very close. Note that \( \frac {e^r2^x - e^x1^x}{r_2 - r_1} \) is a solution when the roots are distinct. When we take the limit as \(r_1\) goes to \(r_2\), we are really taking the derivative of \(e^{rx} \) using \(r\) as the variable. Therefore, the limit is \( xe^{rx}\), and hence this is a solution in the doubled root case.
Below is a video on finding the solution to a differential equation involving repeated roots.
Complex numbers and Euler’s formula
It may happen that a polynomial has some complex roots. For example, the equation \( r^2 + 1 = 0 \) has no real roots, but it does have two complex roots. Here we review some properties of complex numbers.
Complex numbers may seem a strange concept, especially because of the terminology. There is nothing imaginary or really complicated about complex numbers. A complex number is simply a pair of real numbers, \( (a, b) \). We can think of a complex number as a point in the plane. We add complex numbers in the straightforward way, \( (a, b) + (c, d) = (a + c, b + d) \). We define multiplication by
\[(a,b) \times (c,d) \overset{\text{def}}{=} (ac-bd,ad+bc) . \nonumber \]
It turns out that with this multiplication rule, all the standard properties of arithmetic hold. Further, and most importantly \(( 0, 1) \times (0,1) = (-1, 0 )\).
Generally we just write \( (a, b) \) as \( (a + ib)\), and we treat \(i\) as if it were an unknown. We do arithmetic with complex numbers just as we would with polynomials. The property we just mentioned becomes \( i^2 = -1\). So whenever we see \(i^2\), we replace it by \(-1\). The numbers \(i\) and \(-i\) are the two roots of \(r^2 + 1 = 0\).
Note that engineers often use the letter \(j\) instead of \(i\) for the square root of \(-1\). We will use the mathematicians’ convention and use \(i\).
Make sure you understand (that you can justify) the following identities:
- \( i^2 = -1, i^3 = -1, i^4 = 1 \),
- \( \frac {1}{i} = -i \),
- \( (3 -7i)(-2 -9i) = \dots = -69 - 13i \) ,
- \( (3 - 2i)(3 + 2i) = 3^2 - {(2i)}^2 = 3^2 + 2^2 = 13 \) ,
- \( \frac {1}{3-2i} = \frac {1}{3-2i} \frac {3+2i}{3+2i} = \frac{3+2i}{13} = \frac {3}{13} + \frac{2}{13} i \) .
We can also define the exponential \(e^{a+ib}\) of a complex number. We do this by writing down the Taylor series and plugging in the complex number. Because most properties of the exponential can be proved by looking at the Taylor series, these properties still hold for the complex exponential. For example the very important property: \(e^{x+y} = e^xe^y\). This means that \(e^{a+ib} = e^ae^{ib} \). Hence if we can compute \(e^{ib}\), we can compute \(e^{a+ib}\). For \(e^{ib}\) we use the so-called Euler’s formula .
Euler's Formula
\[ e^{i\theta} = \cos \theta + i \sin \theta \quad { \it{~and~ } }\quad e^{-i\theta} = \cos \theta - i\sin \theta \nonumber \]
In other words, \(e^{a+ib}=e^{a}(\cos (b)+i\sin (b))=e^{a}\cos (b)+ie^{a}\sin (b)\).
Using Euler’s formula, check the identities :
\[ \cos \theta = \frac { e^{i \theta} + e^{-i \theta}}{2} \quad\text{and}\quad \sin \theta = \frac { e^{i \theta} - e^{-i \theta}}{2i} \nonumber \]
Double angle identities: Start with \( e^{i (2 \theta)} = {(e^{i \theta})}^2 \). Use Euler on each side and deduce :
- Answer
-
\[ \cos (2 \theta) = {\cos}^2 \theta - {\sin}^2 \theta \quad\text{and}\quad \sin (2 \theta) = 2 \sin \theta \cos \theta \nonumber \]
For a complex number \(a + ib\) we call \(a\) the real part and \(b\) the imaginary part of the number. Often the following notation is used,
\[ \text{Re}(a + ib) =a \quad\text{and}\quad \text{Im} (a + ib) = b \nonumber \]
Complex roots
Suppose that the equation \( ay'' + by' + cy = 0\) has the characteristic equation \(ar^2 + br + c = 0 \) that has complex roots. By the quadratic formula, the roots are \( \dfrac{-b \pm \sqrt {b^2 - 4ac}}{2a}\). These roots are complex if \(b^2 - 4ac < 0 \). In this case the roots are
\[r_1, r_2 = \frac {-b}{2a} \pm i \dfrac { \sqrt {4ac - b^2}}{2a} \nonumber \]
As you can see, we always get a pair of roots of the form \( \alpha \pm i \beta \). In this case we can still write the solution as
\[ y = C_1e^{(\alpha + i \beta )x} + C_2e^{(\alpha - i\beta)x} \nonumber \]
However, the exponential is now complex valued. We would need to allow \(C_1\) and \(C_2\) to be complex numbers to obtain a real-valued solution (which is what we are after). While there is nothing particularly wrong with this approach, it can make calculations harder and it is generally preferred to find two real-valued solutions.
Here we can use Euler’s formula . Let
\[ y_1 = e^{(\alpha + i\beta)x} \quad\text{and}\quad y_2 = e^{( \alpha - i \beta ) x} \nonumber \]
Then note that
\[\begin{align}\begin{aligned} y_1 &= e^{ax} \cos (\beta x) + ie^{ax} \sin ( \beta x) \\ y_2 &= e^{ax} \cos (\beta x) - ie^{ax} \sin (\beta x) \end{aligned}\end{align} \nonumber \]
Linear combinations of solutions are also solutions. Hence,
\[\begin{align}\begin{aligned} y_3 &= \frac {y_1 + y_2}{2} = e^{ax} \cos (\beta x) \\ y_4 &= \frac {y_1 - y_2}{2i} = e^{ax} \sin (\beta x) \end{aligned}\end{align} \nonumber \]
are also solutions. Furthermore, they are real-valued. It is not hard to see that they are linearly independent (not multiples of each other). Therefore, we have the following theorem.
For the homegneous second order ODE
\[ ay'' + by' + cy = 0 \nonumber \]
If the characteristic equation has the roots \( \alpha \pm i \beta \) (when \( b^2 - 4ac < 0 \) ), then the general solution is
\[ y = C_1e^{ax} \cos (\beta x) + C_2e^{ax} \sin (\beta x) \nonumber \]
Below is a video on finding the solution to a differential equation using the principal of superposition.
Find the general solution of \( y'' + k^2 y = 0 \), for a constant \( k > 0 \).
Solution
The characteristic equation is \(r^2 + k^2 = 0 \). Therefore, the roots are \( r = \pm ik \) and by the theorem we have the general solution
\[ y = C_1 \cos (kx) + C_2 \sin (kx) \nonumber \]
Below is a video on finding the solution to a differential equation involving complex roots.
Find the solution of \(y'' - 6y' + 13y = 0, y(0) = 0, y'(0) = 10. \)
Solution
The characteristic equation is \( r^2 - 6r + 13 = 0 \). By completing the square we get \( {(r -3)}^2 + 2^2 = 0 \) and hence the roots are \( r = 3 \pm 2i\). By the theorem we have the general solution
\[y = C_1e^{3x} \cos (2x) + C_2 e^{3x} \sin (2x) \nonumber \]
To find the solution satisfying the initial conditions, we first plug in zero to get
\[ 0 = y(0) = C_1e^0 \cos 0 + C_2e^0 \sin 0 = C_1 \nonumber \]
Hence \(C_1 = 0 \) and \(y = C_2e^{3x} \sin (2x) \). We differentiate
\[ y' = 3C_2 e^{3x} \sin (2x) + 2C_2e^{3x} \cos (2x) \nonumber \]
We again plug in the initial condition and obtain \(10 = y'(0) = 2C_2\), or \( C_2 = 5 \). Hence the solution we are seeking is
\[ y = 5e^{3x} \sin (2x) \nonumber \]
Below is a video on finding the solution to an initial value problem.
Below is a video on finding the solution to a differential equation given initial values.
Below is another video on finding the solution to a differential equation given initial values.
Footnotes
[1] Making an educated guess with some parameters to solve for is such a central technique in differential equations, that people sometimes use a fancy name for such a guess: ansatz , German for “initial placement of a tool at a work piece.” Yes, the Germans have a word for that. | 2,949 | common-pile/libretexts_filtered | https://math.libretexts.org/Courses/Lake_Tahoe_Community_College/MAT-204%3A_Differential_Equations_for_Science_(Lebl_and_Trench)/04%3A_Higher_order_linear_ODEs/4.04%3A_Constant_coefficient_second_order_linear_ODEs | libretexts | libretexts-0000.json.gz:14241 | https://math.libretexts.org/Courses/Lake_Tahoe_Community_College/MAT-204%3A_Differential_Equations_for_Science_(Lebl_and_Trench)/04%3A_Higher_order_linear_ODEs/4.04%3A_Constant_coefficient_second_order_linear_ODEs |
VtSAPRba_-IQv7jn | The Theory and Practice of Model Aeroplaning | Produced by Chris Curnow, Mark Young and the Online
[Illustration: THE MOST IMPORTANT "TOOL" IN THE BUILDING OF MODEL
AEROPLANES.
[_Illustration by permission from_ MESSRS. A. GALLENKAMP & CO'S.
CHEMICAL CATALOGUE.]]
THE THEORY AND PRACTICE
OF
MODEL AEROPLANING
BY
V.E. JOHNSON, M.A.
AUTHOR OF
'THE BEST SHAPE FOR AN AIRSHIP,' 'SOARING FLIGHT,'
'HOW TO ADVANCE THE SCIENCE OF AERONAUTICS,'
'HOW TO BUILD A MODEL AEROPLANE,' ETC.
"Model Aeroplaning is an Art in itself"
London
E. & F.N. SPON, LTD., 57 HAYMARKET
New York
SPON & CHAMBERLAIN, 123 LIBERTY STREET
1910
PREFACE
The object of this little book is not to describe how to construct
some particular kind of aeroplane; this has been done elsewhere: but
to narrate in plain language the general practice and principles of
model aeroplaning.
There is a _science_ of model aeroplaning--just as there is a science
of model yachting and model steam and electric traction, and an
endeavour is made in the following pages to do in some measure for
model aeroplanes what has already been done for model yachts and
locomotives. To achieve the best results, theory and practice must go
hand in hand.
From a series of carefully conducted experiments empirical formulæ can
be obtained which, combined later with mathematical induction and
deduction, may lead, not only to a more accurate and generalized law
than that contained in the empirical formula, but to valuable
deductions of a totally new type, embodying some general law hitherto
quite unknown by experimentalists, which in its turn may serve as a
foundation or stepping stone for suggesting other experiments and
empirical formulæ which may be of especial importance, to be treated
in _their_ turn like their predecessor. By "especial importance," I
mean not only to "model," but "Aeroplaning" generally.
As to the value of experiments on or with models with respect to
full-sized machines, fifteen years ago I held the opinion that they
were a very doubtful factor. I have since considerably modified that
view, and now consider that experiments with models--if properly
carried out, and given due, not _undue_, weight--both can and will be
of as much use to the science of Aeronautics as they have already
proved themselves to be in that of marine engineering.
The subject of model propellers and motors has been somewhat fully
dealt with, as but little has been published (in book form, at any
rate) on these all-important departments. On similar grounds the
reasons why and how a model aeroplane flies have been practically
omitted, because these have been dealt with more or less in every book
on heavier-than-air machines.
Great care has been exercised in the selection of matter, and in the
various facts stated herein; in most cases I have personally verified
them; great pains have also been exercised to exclude not only
misleading, but also doubtful matter. I have no personal axe to grind
whatever, nor am I connected either directly or indirectly with any
firm of aeroplane builders, model or otherwise.
The statements contained in these pages are absolutely free from bias
of any kind, and for them I am prepared to accept full responsibility.
I have to thank Messrs. A.W. GAMAGE (Holborn) for the use of various
model parts for testing purposes, and also for the use of various
electros from their modern Aviation Catalogue; also Messrs. T.W.K.
CLARKE & CO., of Kingston-on-Thames. For the further use of electros,
and for permission to reproduce illustrations which have previously
appeared in their papers, I must express my acknowledgment and thanks
to the publishers of the "Model Engineer," "Flight," and the "Aero."
Corrections and suggestions of any kind will be gratefully received,
and duly acknowledged.
V.E. JOHNSON.
CONTENTS
INTRODUCTION.
PAGE
§§ 1-5. The two classes of models--First requisite of a model
aeroplane. § 6. An art in itself. § 7. The leading principle 1
CHAPTER I.
THE QUESTION OF WEIGHT.
§§ 1-2. Its primary importance both in rubber and
power-driven models--Professor Langley's experiences. § 3.
Theoretical aspect of the question. § 4. Means whereby more
weight can be carried--How to obtain maximum strength with
minimum weight. § 5. Heavy models versus light ones 4
CHAPTER II.
THE QUESTION OF RESISTANCE.
§ 1. The chief function of a model in the medium in which it
travels. § 2. Resistance considered as load percentage. § 3.
How made up. § 4. The shape of minimum resistance. § 5. The
case of rubber-driven models. § 6. The aerofoil
surface--Shape and material as affecting this question. § 7.
Skin friction--Its coefficient. § 8. Experimental proofs of
its existence and importance 7
CHAPTER III.
THE QUESTION OF BALANCE.
§ 1. automatic stability essential in a flying model. § 2.
theoretical researches on this question. §§ 3-6. a brief
summary of the chief conclusions arrived at--remarks on and
deductions from the same--conditions for automatic stability.
§ 7. theory and practice--stringfellow--pénaud--tatin--the
question of fins--clarke's models--some further
considerations. § 8. longitudinal stability. § 9. transverse
stability. § 10. the dihedral angle. § 11. different forms of
the latter. § 12. the "upturned" tip. § 13. the most
efficient section 13
CHAPTER IV.
THE MOTIVE POWER.
SECTION I.--RUBBER MOTORS.
§ 1. Some experiments with rubber cord. § 2. Its extension
under various weights. § 3. The laws of elongation
(stretching)--Permanent set. § 4. Effects of elongation on
its volume. § 5. "Stretched-twisted" rubber cord--Torque
experiments with rubber strands of varying length and number.
§ 6. Results plotted as graphs--Deductions--Various
relations--How to obtain the most efficient
results--Relations between the torque and the number of
strands, and between the length of the strands and their
number. § 7. Analogy between rubber and "spring"
motors--Where it fails to hold. § 8. Some further practical
deductions. § 9. The number of revolutions that can be given
to rubber motors. § 10. The maximum number of turns. § 11.
"Lubricants" for rubber. § 12. Action of copper upon rubber.
§ 12A. Action of water, etc. § 12B. How to preserve rubber.
§ 13. To test rubber. § 14. The shape of the section. § 15.
Size of section. § 16. Geared rubber motors. § 17. The only
system worth consideration--Its practical difficulties. § 18.
Its advantages 24
SECTION II.--OTHER FORMS OF MOTORS.
§ 18A. _Spring motors_; their inferiority to rubber. § 18B.
The most efficient form of spring motor. § 18C. _Compressed
air motors_--A fascinating form of motor, "on paper." § 18D.
The pneumatic drill--Application to a model aeroplane--Length
of possible flight. § 18E. The pressure in motor-car tyres.
§ 19. Hargraves' compressed air models--The best results
compared with rubber motors. § 20. The effect of heating the
air in its passage from the reservoir to the motor--The great
gain in efficiency thereby attained--Liquid air--Practical
drawbacks to the compressed-air motor. § 21. Reducing
valves--Lowest working pressure. § 22. The inferiority of
this motor compared with the steam engine. § 22A. Tatin's
air-compressed motor. § 23. _Steam engine_--Steam engine
model--Professor Langley's models--His experiment with
various forms of motive power--Conclusions arrived at. § 24.
His steam engine models--Difficulties and failures--and final
success--The "boiler" the great difficulty--His model
described. § 25. The use of spirit or some very volatile
hydrocarbon in the place of water. § 26. Steam turbines.
§ 27. Relation between "difficulty in construction" and the
"size of the model." § 28. Experiments in France. § 29.
_Petrol motors._--But few successful models. § 30. Limit to
size. § 31. Stanger's successful model described and
illustrated. § 32. One-cylinder petrol motors. § 33.
_Electric motors_ 39
CHAPTER V.
PROPELLERS OR SCREWS.
§ 1. The position of the propeller. § 2. The number of
blades. § 3. Fan _versus_ propeller. § 4. The function of a
propeller. § 5. The pitch. § 6. Slip. § 7. Thrust. § 8. Pitch
coefficient (or ratio). § 9. Diameter. § 10. Theoretical
pitch. § 11. Uniform pitch. § 12. How to ascertain the pitch
of a propeller. § 13. Hollow-faced blades. § 14. Blade area.
§ 15. Rate of rotation. § 16. Shrouding. § 17. General
design. § 18. The shape of the blades. § 19. Their general
contour--Propeller design--How to design a propeller. § 20.
Experiments with propellers--Havilland's design for
experiments--The author experiments on dynamic thrust and
model propellers generally. § 21. Fabric-covered screws.
§ 22. Experiments with twin propellers. § 23. The Fleming
Williams propeller. § 24. Built-up _v._ twisted wooden
propellers 52
CHAPTER VI.
THE QUESTION OF SUSTENTATION.
THE CENTRE OF PRESSURE.
§ 1. The centre of pressure--Automatic stability. § 2.
Oscillations. § 3. Arched surfaces and movements of the
centre of pressure--Reversal. § 4. The centre of gravity and
the centre of pressure. § 5. Camber. § 6. Dipping front
edge--Camber--The angle of incidence and camber--Attitude of
the Wright machine. § 7. The most efficient form of camber.
§ 8. The instability of a deeply cambered surface. § 9.
Aspect ratio. § 10. Constant or varying camber. § 11. Centre
of pressure on arched surfaces 78
CHAPTER VII.
MATERIALS FOR AEROPLANE
CONSTRUCTION.
§ 1. The choice strictly limited. § 2. Bamboo. § 3.
Ash--spruce-- whitewood--poplar. § 4. Steel. § 5. Umbrella
section steel. § 6. Steel wire. § 7. Silk. § 8. Aluminium and
magnalium. § 9. Alloys. § 10. Sheet ebonite--Vulcanized
fibre--Sheet celluloid--Mica 86
CHAPTER VIII.
HINTS ON THE BUILDING OF MODEL
AEROPLANES.
§ 1. The chief difficulty to overcome. § 2. General
design--The principle of continuity. § 3. Simple monoplane.
§ 4. Importance of soldering. § 5. Things to avoid. § 6.
Aerofoil of metal--wood--or fabric. § 7. Shape of aerofoil.
§ 8. How to camber an aerocurve without ribs. § 9. Flexible
joints. § 10. Single surfaces. § 11. The rod or tube carrying
the rubber motor. § 12. Position of the rubber. § 13. The
position of the centre of pressure. § 14. Elevators and
tails. § 15. Skids _versus_ wheels--Materials for skids.
§ 16. Shock absorbers, how to attach--Relation between the
"gap" and the "chord" 93
CHAPTER IX.
THE STEERING OF THE MODEL.
§ 1. A problem of great difficulty--Effects of propeller
torque. § 2. How obviated. § 3. The two-propeller
solution--The reason why it is only a partial success. § 4.
The _speed_ solution. § 5. Vertical fins. § 6. Balancing tips
or ailerons. § 7. Weighting. § 8. By means of transversely
canting the elevator. § 9. The necessity for some form of
"keel" 105
CHAPTER X.
THE LAUNCHING OF THE MODEL.
§ 1. The direction in which to launch them. § 2. The
velocity--wooden aerofoils and fabric-covered
aerofoils--Poynter's launching apparatus. § 3. The launching
of very light models. § 4. Large size and power-driven
models. § 5. Models designed to rise from the
ground--Paulhan's prize model. § 6. The setting of the
elevator. § 7. The most suitable propeller for this form of
model. § 8. Professor Kress' method of launching. § 9. How to
launch a twin screw model. § 10. A prior revolution of the
propellers. § 11. The best angle at which to launch a model 109
CHAPTER XI.
HELICOPTER MODELS.
§ 1. Models quite easy to make. § 2. Sir George Cayley's
helicopter model. § 3. Phillips' successful power-driven
model. § 4. Toy helicopters. § 5. Incorrect and correct way
of arranging the propellers. § 6. Fabric covered screws. § 7.
A design to obviate weight. § 8. The question of a fin or
keel. 113
CHAPTER XII.
EXPERIMENTAL RECORDS 116
CHAPTER XIII.
MODEL FLYING COMPETITIONS.
§ 1. A few general details concerning such. § 2. Aero Models
Association's classification, etc. § 3. Various points to be
kept in mind when competing 119
CHAPTER XIV.
USEFUL NOTES, TABLES, FORMULÆ, ETC.
§ 1. Comparative velocities. § 2. Conversions. § 3. Areas of
various shaped surfaces. § 4. French and English measures.
§ 5. Useful data. § 6. Table of equivalent inclinations. § 7.
Table of skin friction. § 8. Table I. (metals). § 9. Table
II. (wind pressures). § 10. Wind pressure on various shaped
bodies. § 11. Table III. (lift and drift) on a cambered
surface. § 12. Table IV. (lift and drift)--On a plane
aerofoil--Deductions. § 13. Table V. (timber). § 14. Formula
connecting weight lifted and velocity. § 15. Formula
connecting models of similar design but different weights.
§ 16. Formula connecting power and speed. § 17. Propeller
thrust. § 18. To determine experimentally the static thrust
of a propeller. § 19. Horse-power and the number of
revolutions. § 20. To compare one model with another. § 21.
Work done by a clockwork spring motor. § 22. To ascertain the
horse-power of a rubber motor. § 23. Foot-pounds of energy in
a given weight of rubber--Experimental determination of.
§ 24. Theoretical length of flight. § 25. To test different
motors. § 26. Efficiency of a model. § 27. Efficiency of
design. § 28. Naphtha engines. § 29. Horse-power and weight
of model petrol motors. § 30. Formula for rating the same.
§ 30A. Relation between static thrust of propeller and total
weight of model. § 31. How to find the height of an
inaccessible object (kite, balloon, etc.). § 32. Formula for
I.H.P. of model steam engines 125
APPENDIX A. Some models which have won medals at open
competitions 143
GLOSSARY OF TERMS USED IN MODEL AEROPLANING.
_Aeroplane._ A motor-driven flying machine which relies upon surfaces
for its support in the air.
_Monoplane_ (single). An aeroplane with one pair of outstretched
wings.
_Aerofoil._ These outstretched wings are often called aerofoil
surfaces. One pair of wings forming one aerofoil surface.
_Monoplane_ (double). An aeroplane with two aerofoils, one behind the
other or two main planes, tandem-wise.
_Biplane._ An aeroplane with two aerofoils, one below the other, or
having two main planes superposed.
_Triplane._ An aeroplane having three such aerofoils or three such
main planes.
_Multiplane._ Any such machine having more than three of the above.
_Glider._ A motorless aeroplane.
_Helicopter._ A flying machine in which propellers are employed to
raise the machine in the air by their own unaided efforts.
_Dihedral Angle._ A dihedral angle is an angle made by two surfaces
that do not lie in the same plane, i.e. when the aerofoils are
arranged V-shaped. It is better, however, to somewhat extend this
definition, and not to consider it as necessary that the two surfaces
_do_ actually meet, but would do so if produced thus in figure. BA and
CD are still dihedrals, sometimes termed "upturned tips."
[Illustration: Dihedrals.]
_Span_ is the distance from tip to tip of the main supporting surface
measured transversely (across) the line of flight.
_Camber_ (a slight arching or convexity upwards). This term denotes
that the aerofoil has such a curved transverse section.
_Chord_ is the distance between the entering (or leading) edge of the
main supporting surface (aerofoil) and the trailing edge of the same;
also defined as the fore and aft dimension of the main planes measured
in a straight line between the leading and trailing edges.
span
_Aspect Ratio_ is -----
chord
_Gap_ is the vertical distance between one aerofoil and the one which
is immediately above it.
(The gap is usually made equal to the chord).
_Angle of Incidence._ The angle of incidence is the angle made by the
chord with the line of flight.
AB = chord. AB = cambered surface.
SP = line of flight. ASP = {alpha} = L of incidence.]
_Width._ The width of an aerofoil is the distance from the front to
the rear edge, allowing for camber.
_Length._ This term is usually applied to the machine as a whole, from
the front leading edge of elevator (or supports) to tip of tail.
_Arched._ This term is usually applied to aerofoil surfaces which dip
downwards like the wings of a bird. The curve in this case being at
right angles to "camber." A surface can, of course, be both cambered
and arched.
_Propeller._ A device for propelling or pushing an aeroplane forward
or for raising it vertically (lifting screw).
_Tractor Screw._ A device for pulling the machine (used when the
propeller is placed in the front of the machine).
_Keel._ A vertical plane or planes (usually termed "fins") arranged
longitudinally for the purposes of stability and steering.
_Tail._ The plane, or group of planes, at the rear end of an
aeroplane for the purpose chiefly of giving longitudinal stability. In
such cases the tail is normally (approx.) horizontal, but not
unfrequently vertical tail-pieces are fitted as well for steering
(transversely) to the right or left, or the entire tail may be twisted
for the purpose of transverse stability (vide _Elevator_). Such
appendages are being used less and less with the idea of giving actual
support.
_Rudder_ is the term used for the vertical plane, or planes, which are
used to steer the aeroplane sideways.
_Warping._ The flexing or bending of an aerofoil out of its normal
shape. The rear edges near the tips of the aerofoil being dipped or
tilted respectively, in order to create a temporary difference in
their inclinations to the line of flight. Performed in conjunction
with rudder movements, to counteract the excessive action of the
latter.
_Ailerons_ (also called "righting-tips," "balancing-planes," etc.).
Small aeroplanes in the vicinity of the tips of the main aerofoil for
the purpose of assisting in the maintenance of equilibrium or for
steering purposes either with or without the assistance of the rudder.
_Elevator._ The plane, or planes, in front of the main aerofoil used
for the purpose of keeping the aeroplane on an even keel, or which
cause (by being tilted or dipped) the aeroplane to rise or fall (vide
_Tail_).
MODEL AEROPLANING
INTRODUCTION.
§ 1. Model Aeroplanes are primarily divided into two classes: first,
models intended before all else to be ones that shall _fly_; secondly,
_models_, using the word in its proper sense of full-sized machines.
Herein model aeroplanes differ from model yachts and model
locomotives. An extremely small model locomotive _built to scale_ will
still _work_, just as a very small yacht built to scale will _sail_;
but when you try to build a scale model of an "Antoinette" monoplane,
_including engine_, it cannot be made to fly unless the scale be a
very large one. If, for instance, you endeavoured to make a 1/10 scale
model, your model petrol motor would be compelled to have eight
cylinders, each 0·52 bore, and your magneto of such size as easily to
pass through a ring half an inch in diameter. Such a model could not
possibly work.[1]
_Note._--Readers will find in the "Model Engineer" of June 16,
1910, some really very fine working drawings of a prize-winning
Antoinette monoplane model.
§ 2. Again, although the motor constitutes the _chief_, it is by no
means the sole difficulty in _scale_ model aeroplane building. To
reproduce to scale at _scale weight_, or indeed anything approaching it,
_all_ the _necessary_--in the case of a full-sized machine--framework is
not possible in a less than 1/5 scale.
§ 3. Special difficulties occur in the case of any prototype taken.
For instance, in the case of model Blériots it is extremely difficult
to get the centre of gravity sufficiently forward.
§ 4. Scale models of actual flying machines _that will fly_ mean
models _at least_ 10 or 12 feet across, and every other dimension in
like proportion; and it must always be carefully borne in mind that
the smaller the scale the greater the difficulties, but not in the
same proportion--it would not be _twice_ as difficult to build a
¼-in. scale model as a ½-in., but _four_, _five_ or _six_ times as
difficult.
§ 5. Now, the _first_ requirement of a model aeroplane, or flying
machine, is that it shall FLY.
As will be seen later on--unless the machine be of large size, 10 feet
and more spread--the only motor at our disposal is the motor of
twisted rubber strands, and this to be efficient requires to be long,
and is of practically uniform weight throughout; this alone alters the
entire _distribution of weight_ on the machine and makes:
§ 6. "=Model Aeroplaning an Art in itself=," and as such we propose to
consider it in the following pages.
We have said that the first requisite of a model aeroplane is that it
shall fly, but there is no necessity, nor is it indeed always to be
desired, that this should be its only one, unless it be built with the
express purpose of obtaining a record length of flight. For ordinary
flights and scientific study what is required is a machine in which
minute detail is of secondary importance, but which does along its
main lines "_approximate_ to the real thing."
§ 7. Simplicity should be the first thing aimed at--simplicity means
efficiency, it means it in full-sized machines, still more does it
mean it in models--and this very question of simplicity brings us to
that most important question of all, namely, the question of _weight_.
FOOTNOTE:
[1] The smallest working steam engine that the writer has ever heard
of has a net weight of 4 grains. One hundred such engines would be
required to weigh one ounce. The bore being 0·03 in., and stroke 1/32
of an inch, r.p.m. 6000 per min., h.p. developed 1/489000 ("Model
Engineer," July 7, 1910). When working it hums like a bee.
CHAPTER I.
THE QUESTION OF WEIGHT.
§ 1. The following is an extract from a letter that appeared in the
correspondence columns of "The Aero."[2]
"To give you some idea how slight a thing will make a model behave
badly, I fitted a skid to protect the propeller underneath the
aeroplane, and the result in retarding flight could be seen very
quickly, although the weight of the skid was almost nil.[3] To all
model makers who wish to make a success I would say, strip all that
useless and heavy chassis off, cut down the 'good, honest stick' that
you have for a backbone to half its thickness, stay it with wire if it
bends under the strain of the rubber, put light silk on the planes,
and use an aluminium[4] propeller. The result will surpass all
expectations."
§ 2. The above refers, of course, to a rubber-motor driven model. Let
us turn to a steam-driven prototype. I take the best known example of
all, Professor Langley's famous model. Here is what the professor has
to say on the question[5]:--
"Every bit of the machinery had to be constructed with scientific
accuracy. It had to be tested again and again. The difficulty of
getting the machine light enough was such that every part of it had to
be remade several times. It would be in full working order when
something would give way, and this part would have to be strengthened.
This caused additional weight, and necessitated cutting off so much
weight from some other part of the machinery. At times the difficulty
seemed almost heartbreaking; but I went on, piece by piece and atom by
atom, until I at last succeeded in getting all the parts of the right
strength and proportion."
How to obtain the maximum strength with the minimum of weight is one
of the, if not the most, difficult problems which the student has to
solve.
§ 3. The theoretical reason why _weight_ is such an all-important item
in model aeroplaning, much more so than in the case of full-size
machines, is that, generally speaking, such models do not fly fast
enough to possess a high weight carrying capacity. If you increase the
area of the supporting surface you increase also the resistance, and
thereby diminish the speed, and are no better off than before. The
only way to increase the weight carrying capacity of a model is to
increase its speed. This point will be recurred to later on. One of
Mr. T.W.K. Clarke's well-known models, surface area 1¼ sq. ft.,
weight 1¼ lb., is stated to have made a flight of 300 yards
carrying 6 oz. of lead. This works out approximately at 21 oz. per sq.
ft.
The velocity (speed) is not stated, but some earlier models by the
same designer, weight 1½ lb., supporting area 1½ sq. ft., i.e.,
at rate of 16 oz. per sq. ft., travelled at a rate of 37 ft. per
second, or 25 miles an hour.
The velocity of the former, therefore, would certainly not be less
than 30 miles an hour.
§ 4. Generally speaking, however, models do not travel at anything
like this velocity, or carry anything like this weight per sq. ft.
An average assumption of 13 to 15 miles an hour does nor err on the
minimum side. Some very light fabric covered models have a speed of
less than even 10 miles an hour. Such, of course, cannot be termed
efficient models, and carry only about 3 oz. per sq. ft. Between these
two types--these two extremes--somewhere lies the "Ideal Model."
The maximum of strength with the minimum of weight can be obtained
only:--
1. By a knowledge of materials.
2. Of how to combine those materials in a most efficient and skilful
manner.
3. By a constant use of the balance or a pair of scales, and noting
(in writing) the weight and result of every trial and every experiment
in the alteration and change of material used. WEIGH EVERYTHING.
§ 5. The reader must not be misled by what has been said, and think
that a model must not weigh anything if it is to fly well. A heavy
model will fly much better against the wind than a light one, provided
that the former _will_ fly. To do this it must fly _fast_. To do this
again it must be well powered, and offer the minimum of resistance to
the medium through which it moves. This means its aerofoil
(supporting) surfaces must be of polished wood or metal. This point
brings us to the question of Resistance, which we will now consider.
FOOTNOTES:
[2] "Aero," May 3, 1910.
[3] Part of this retardation was, of course, "increased resistance."
[4] Personally I do not recommend aluminium.--V.E.J.
[5] "Aeronautical Journal," January 1897, p. 7.
CHAPTER II.
THE QUESTION OF RESISTANCE.
§ 1. It is, or should be, the function of an aeroplane--model or
otherwise--to pass through the medium in which it travels in such a
manner as to leave that medium in as motionless a state as possible,
since all motion of the surrounding air represents so much power
wasted.
Every part of the machine should be so constructed as to move through
the air with the minimum of disturbance and resistance.
§ 2. The resistance, considered as a percentage of the load itself,
that has to be overcome in moving a load from one place to another,
is, according to Mr. F.W. Lanchester, 12½ per cent. in the case of
a flying machine, and 0·1 per cent. in the case of a cargo boat, and
of a solid tyre motor car 3 per cent., a locomotive 1 per cent. Four
times at least the resistance in the case of aerial locomotion has to
be overcome to that obtained from ordinary locomotion on land. The
above refer, of course, to full-sized machines; for a model the
resistance is probably nearer 14 or 15 per cent.
§ 3. This resistance is made up of--
1. Aerodynamic resistance.
2. Head resistance.
3. Skin-friction (surface resistance).
The first results from the necessity of air supporting the model
during flight.
The second is the resistance offered by the framework, wires, edges of
aerofoils, etc.
The third, skin-friction or surface resistance, is very small at low
velocities, but increases as the square of the velocity. To reduce the
resistance which it sets up, all surfaces used should be as smooth as
possible. To reduce the second, contours of ichthyoid, or fish-like,
form should be used, so that the resultant stream-line flow of the
medium shall keep in touch with the surface of the body.
§ 4. As long ago as 1894 a series of experiments were made by the
writer[6] to solve the following problem: given a certain length and
breadth, to find the shape which will offer the least resistance. The
experiments were made with a whirling table 40 ft. in diameter, which
could be rotated so that the extremity of the arm rotated up to a
speed of 45 miles an hour. The method of experimenting was as follows:
The bodies (diam. 4 in.) were balanced against one another at the
extremity of the arm, being so balanced that their motions forward and
backward were parallel. Provision was made for accurately balancing
the parallel scales on which the bodies were suspended without
altering the resistance offered by the apparatus to the air. Two
experiments at least (to avoid error) were made in each case, the
bodies being reversed in the second experiment, the top one being put
at the bottom, and _vice versa_. The conclusions arrived at were:--
For minimum (head) resistance a body should have--
1. Its greatest diameter two-fifths of its entire length from its
head.
2. Its breadth and its depth in the proportion of four to three.
3. Its length at least from five to nine times its greatest breadth
(nine being better than five).
4. A very tapering form of stern, the actual stern only being of just
sufficient size to allow of the propeller shaft passing through. In
the case of twin propellers some slight modification of the stern
would be necessary.
5. Every portion of the body in contact with the fluid to be made as
smooth as possible.
6. A body of such shape gives at most only _one-twentieth_ the
resistance offered by a flat disk of similar maximum sectional area.
_Results since fully confirmed._
[Illustration: FIG. 1.--SHAPE OF LEAST RESISTANCE.]
The design in Fig. 2 is interesting, not only because of its probable
origin, but because of the shape of the body and arrangement of the
propellers; no rudder is shown, and the long steel vertical mast
extending both upwards and downwards through the centre would render
it suitable only for landing on water.
§ 5. In the case of a rubber-driven model, there is no containing body
part, so to speak, a long thin stick, or tubular construction if
preferred, being all that is necessary.
The long skein of elastic, vibrating as well as untwisting as it
travels with the machine through the air, offers some appreciable
resistance, and several experimenters have _enclosed_ it in a light
tube made of _very thin_ veneer wood rolled and glued, or paper even
may be used; such tubes can be made very light, and possess
considerable rigidity, especially longitudinally. If the model be a
biplane, then all the upright struts between the two aerofoils should
be given a shape, a vertical section of which is shown in Fig. 3.
§ 6. In considering this question of resistance, the substance of
which the aerofoil surface is made plays a very important part, as
well as whether that surface be plane or curved. For some reason not
altogether easy to determine, fabric-covered planes offer
_considerably_ more resistance than wooden or metal ones. That they
should offer _more_ resistance is what common sense would lead one to
expect, but hardly to the extent met with in actual practice.
[Illustration: FIG. 2.--DESIGN FOR AN AEROPLANE MODEL (POWER DRIVEN).
This design is attributed to Professor Langley.]
_Built up fabric-covered aeroplanes[7] gain in lightness, but lose in
resistance._ In the case of curved surfaces this difference is
considerably more; one reason, undoubtedly, is that in a built up
model surface there is nearly always a tendency to make this curvature
excessive, and much more than it should be. Having called attention to
this under the head of resistance, we will leave it now to recur to it
later when considering the aerofoil proper.
[Illustration: FIG. 3.--HORIZONTAL SECTION OF VERTICAL STRUT
(ENLARGED.)]
§ 7. Allusion has been made in this chapter to skin friction, but no
value given for its coefficient.[8] Lanchester's value for planes from
½ to 1½ sq. ft. in area, moving about 20 to 30 ft. per second, is
0·009 to 0·015.
Professor Zahm (Washington) gives 0·0026 lb. per sq. ft. at 25 ft. per
second, and at 37 ft. per second, 0·005, and the formula
_f_ = 0·00000778_l_^{·93}_v_^{1·85}
_f_ being the average friction in lb. per sq. in., _l_ the length in
feet, and _v_ the velocity in ft. per second. He also experimented
with various kinds of surfaces, some rough, some smooth, etc.
His conclusion is:--"All even surfaces have approximately the same
coefficient of skin friction. Uneven surfaces have a greater
coefficient." All formulæ on skin friction must at present be accepted
with reserve.
§ 8. The following three experiments, however, clearly prove its
_existence_, and _that it has considerable effect_:--
1. A light, hollow celluloid ball, supported on a stream of air
projected upwards from a jet, rotates in one direction or the other as
the jet is inclined to the left or to the right. (F.W. Lanchester.)
2. When a golf ball (which is rough) is hit so as to have considerable
underspin, its range is increased from 135 to 180 yards, due entirely
to the greater frictional resistance to the air on that side on which
the whirl and the progressive motion combine. (Prof. Tait.)
3. By means of a (weak) bow a golf ball can be made to move point
blank to a mark 30 yards off, provided the string be so adjusted as to
give a good underspin; adjust the string to the centre of the ball,
instead of catching it below, and the drop will be about 8 ft. (Prof.
Tait.)
FOOTNOTES:
[6] _Vide_ "Invention," Feb. 15, 22, and 29, 1896.
[7] Really aerofoils, since we are considering only the supporting
surface.
[8] I.e., to express it as a decimal fraction of the resistance,
encountered by the same plane when moving "face" instead of "edge" on.
CHAPTER III.
THE QUESTION OF BALANCE.
§ 1. It is perfectly obvious for successful flight that any model
flying machine (in the absence of a pilot) must possess a high degree
of automatic stability. The model must be so constructed as to be
naturally stable, _in the medium through which it is proposed to drive
it_. The last remark is of the greatest importance, as we shall see.
§ 2. In connexion with this same question of automatic stability, the
question must be considered from the theoretical as well as from the
practical side, and the labours and researches of such men as
Professors Brian and Chatley, F.W. Lanchester, Captain Ferber,
Mouillard and others must receive due weight. Their work cannot yet be
fully assessed, but already results have been arrived at far more
important than are generally supposed.
The following are a few of the results arrived at from theoretical
considerations; they cannot be too widely known.
(A) Surfaces concave on the under side are not stable unless some form
of balancing device (such as a tail, etc.) is used.
(B) If an aeroplane is in equilibrium and moving uniformly, it is
necessary for stability that it shall tend towards a condition of
equilibrium.
(C) In the case of "oscillations" it is absolutely necessary for
stability that these oscillations shall decrease in amplitude, in
other words, be damped out.
(D) In aeroplanes in which the dihedral angle is excessive or the
centre of gravity very low down, a dangerous pitching motion is quite
likely to be set up. [Analogy in shipbuilding--an increase in the
metacentre height while increasing the stability in a statical sense
causes the ship to do the same.]
(E) The propeller shaft should pass through the centre of gravity of
the machine.
(F) The front planes should be at a greater angle of inclination than
the rear ones.
(G) The longitudinal stability of an aeroplane grows much less when
the aeroplane commences to rise, a monoplane becoming unstable when
the angle of ascent is greater than the inclination of the main
aerofoil to the horizon.
(H) Head resistance increases stability.
(I) Three planes are more stable than two. [Elevator--main
aerofoil--horizontal rudder behind.]
(J) When an aeroplane is gliding (downwards) stability is greater than
in horizontal flight.
(K) A large moment of inertia is inimical (opposed) to stability.
(M) Aeroplanes (naturally) stable up to a certain velocity (speed) may
become unstable when moving beyond that speed. [Possible explanation.
The motion of the air over the edges of the aerofoil becomes
turbulent, and the form of the stream lines suddenly changes.
Aeroplane also probably becomes deformed.]
(N) In a balanced glider for stability a separate surface at a
negative angle to the line of flight is essential. [Compare F.]
(O) A keel surface should be situated well above and behind the centre
of gravity.
(P) An aeroplane is a conservative system, and stability is greatest
when the kinetic energy is a maximum. [Illustration, the pendulum.]
§ 3. Referring to A. Models with a plane or flat surface are not
unstable, and will fly well without a tail; such a machine is called a
simple monoplane.
[Illustration: FIG. 4.--ONE OF MR. BURGE WEBB'S SIMPLE MONOPLANES.
Showing balance weight A (movable), and also his winding-up gear--a
very handy device.]
§ 4. Referring to D. Many model builders make this mistake, i.e., the
mistake of getting as low a centre of gravity as possible under the
quite erroneous idea that they are thereby increasing the stability of
the machine. Theoretically the _centre of gravity should be the centre
of head resistance, as also the centre of pressure_.
In practice some prefer to put the centre of gravity in models
_slightly_ above the centre of head resistance, the reason being that,
generally speaking, wind gusts have a "lifting" action on the machine.
It must be carefully borne in mind, however, that if the centre of
wind pressure on the aerofoil surface and the centre of gravity do not
coincide, no matter at what point propulsive action be applied, it can
be proved by quite elementary mechanics that such an arrangement,
known as "acentric," produces a couple tending to upset the machine.
This action is the probable cause of many failures.
[Illustration: FIG. 5.--THE STRINGFELLOW MODEL MONOPLANE OF 1848.]
§ 5. Referring to E. If the propulsive action does not pass through
the centre of gravity the system again becomes "acentric." Even
supposing condition D fulfilled, and we arrive at the following most
important result, viz., that for stability:--
THE CENTRES OF GRAVITY, OF PRESSURE, OF HEAD RESISTANCE, SHOULD BE
COINCIDENT, AND THE PROPULSIVE ACTION OF THE PROPELLER PASS THROUGH
THIS SAME POINT.
[Illustration: FIG. 6.--THE STRINGFELLOW MODEL TRIPLANE OF 1868.]
§ 6. Referring to F and N--the problem of longitudinal stability.
There is one absolutely essential feature not mentioned in F or N, and
that is for automatic longitudinal stability _the two surfaces, the
aerofoil proper and the balancer_ (elevator or tail, or both), _must
be separated by some considerable distance, a distance not less than
four times the width of the main aerofoil_.[9] More is better.
[Illustration: FIG. 7. _PÉNAUD 1871_]
§ 7. With one exception (Pénaud) early experimenters with model
aeroplanes had not grasped this all-important fact, and their models
would not fly, only make a series of jumps, because they failed to
balance longitudinally. In Stringfellow's and Tatin's models the main
aerofoil and balancer (tail) are practically contiguous.
Pénaud in his rubber-motored models appears to have fully realised
this (_vide_ Fig. 7), and also the necessity for using long strands of
rubber. Some of his models flew 150 ft., and showed considerable
stability.
[Illustration: FIG. 8.--TATIN'S AEROPLANE (1879).
Surface 0·7 sq. metres, total weight 1·75 kilogrammes, velocity of
sustentation 8 metres a second. Motor, compressed air (for description
see § 23, ch. iv). Revolved round and round a track tethered to a post
at the centre. In one of its jumps it cleared the head of a
spectator.]
With three surfaces one would set the elevator at a slight plus angle,
main aerofoil horizontal (neither positive nor negative), and the tail
at a corresponding negative angle to the positive one of the elevator.
Referring to O.[10] One would naturally be inclined to put a keel
surface--or, in other words, vertical fins--beneath the centre of
gravity, but D shows us this may have the opposite effect to what we
might expect.
In full-sized machines, those in which the distance between the main
aerofoil and balancers is considerable (like the Farman) show
considerable automatic longitudinal stability, and those in which it
is short (like the Wright) are purposely made so with the idea of
doing away with it, and rendering the machine quicker and more
sensitive to personal control. In the case of the Stringfellow and
Tatin models we have the extreme case--practically the bird entirely
volitional and personal--which is the opposite in every way to what we
desire on a model under no personal or volitional control at all.
[Illustration: FIG. 9.--CLARK'S MODEL FLYER.
Main aerofoil set at a slight negative angle. Dihedral angles on both
aerofoils.]
The theoretical conditions stated in F and N are fully borne out in
practice.
And since a curved aerofoil even when set at a _slight_ negative
angle has still considerable powers of sustentation, it is possible to
give the main aerofoil a slight negative angle and the elevator a
slight positive one. This fact is of the greatest importance, since it
enables us to counteract the effect of the travel of the "centre of
pressure."[11]
[Illustration: FIG. 10.--LARGE MODEL MONOPLANE.
Designed and constructed by the author, with vertical fin (no dihedral
angle). With a larger and more efficient propeller than the one here
shown some excellent flights were obtained. Constructed of bamboo and
nainsook. Stayed with steel wire.]
§ 8. Referring to I. This, again, is of primary importance in
longitudinal stability. The Farman machine has three such
planes--elevator, main aerofoil, tail the Wright originally had _not_,
but is now being fitted with a tail, and experiments on the
Short-Wright biplane have quite proved its stabilising efficiency.
The three plane (triple monoplane) in the case of models has been
tried, but possesses no advantage so far over the double monoplane
type. The writer has made many experiments with vertical fins, and has
found the machine very stable, even when the fin or vertical keel is
placed some distance above the centre of gravity.
§ 9. The question of transverse (side to side) stability at once
brings us to the question of the dihedral angle, practically similar
in its action to a flat plane with vertical fins.
[Illustration: FIG. 11.--SIR GEORGE CAYLEY'S FLYING MACHINE.
Eight feathers, two corks, a thin rod, a piece of whalebone, and a
piece of thread.]
§ 10. The setting up of the front surface at an angle to the rear, or
the setting of these at corresponding compensatory angles already
dealt with, is nothing more nor less than the principle of the
dihedral angle for longitudinal stability.
[Illustration: FIG. 12.--VARIOUS FORMS OF DIHEDRALS.]
As early as the commencement of last century Sir George Cayley (a
man more than a hundred years ahead of his times) was the first to
point out that two planes at a dihedral angle constitute a basis of
stability. For, on the machine heeling over, the side which is
required to rise gains resistance by its new position, and that which
is required to sink loses it.
§ 11. The dihedral angle principle may take many forms.
As in Fig. 12 _a_ is a monoplane, the rest biplanes. The angles and
curves are somewhat exaggerated. It is quite a mistake to make the
angle excessive, the "lift" being thereby diminished. A few degrees
should suffice.
Whilst it is evident enough that transverse stability is promoted by
making the sustaining surface trough-shaped, it is not so evident what
form of cross section is the most efficient for sustentation and
equilibrium combined.
[Illustration: FIG. 13.]
It is evident that the righting moment of a unit of surface of an
aeroplane is greater at the outer edge than elsewhere, owing to the
greater lever arm.
§ 12. The "upturned tip" dihedral certainly appears to have the
advantage.
_The outer edges of the aerofoil then should be turned upward for the
purpose of transverse stability, while the inner surface should remain
flat or concave for greater support._
§ 13. The exact most favourable outline of transverse section for
stability, steadiness and buoyancy has not yet been found; but the
writer has found the section given in Fig. 13, a very efficient one.
FOOTNOTES:
[9] If the width be not uniform the mean width should be taken.
[10] This refers, of course, to transverse stability.
[11] See ch. vi.
CHAPTER IV.
THE MOTIVE POWER.
SECTION I.--RUBBER MOTORS.
§ 1. Some forty years have elapsed since Pénaud first used elastic
(rubber) for model aeroplanes, and during that time no better
substitute (in spite of innumerable experiments) has been found. Nor
for the smaller and lighter class of models is there any likelihood of
rubber being displaced. Such being the case, a brief account of some
experiments on this substance as a motive power for the same may not
be without interest. The word _elastic_ (in science) denotes: _the
tendency which a body has when distorted to return to its original
shape_. Glass and ivory (within certain limits) are two of the most
elastic bodies known. But the limits within which most bodies can be
distorted (twisted or stretched, or both) without either fracture or a
LARGE _permanent_ alteration of shape is very small. Not so rubber--it
far surpasses in this respect even steel springs.
§ 2. Let us take a piece of elastic (rubber) cord, and stretch it with
known weights and observe carefully what happens. We shall find that,
first of all: _the extension is proportional to the weight
suspended_--but soon we have an _increasing_ increase of extension. In
one experiment made by the writer, when the weights were removed the
rubber cord remained 1/8 of an inch longer, and at the end of an hour
recovered itself to the extent of 1/16, remaining finally permanently
1/16 of an inch longer. Length of elastic cord used in this experiment
8-1/8 inches, 3/16 of an inch thick. Suspended weights, 1 oz. up to 64
oz. Extension from ¼ inch up to 24-5/8 inches. Graph drawn in Fig.
14, No. B abscissæ extension in eighths of an inch, ordinates weights
in ounces. So long as the graph is a straight line it shows the
extension is proportional to the suspended weight; afterwards in
excess.
[Illustration: FIG. 14.--WEIGHT AND EXTENSION.
B, rubber 3/16 in. thick; C, 2/16 in. thick; D, 1/16 in. thick. A,
theoretical line if extension were proportional to weight.]
In this experiment we have been able to stretch (distort) a piece of
rubber to more than three times its original length, and afterwards it
finally returns to almost its original length: not only so, a piece of
rubber cord can be stretched to eight or nine times its original
length without fracture. Herein lies its supreme advantage over steel
or other springs. Weight for weight more energy can be got or more
work be done by stretched (or twisted, or, to speak more correctly, by
stretched-twisted) rubber cord than from any form of steel spring.[12]
It is true it is stretched--twisted--far beyond what is called the
"elastic limit," and its efficiency falls off, but with care not
nearly so quickly as is commonly supposed, but in spite of this and
other drawbacks its advantages far more than counterbalance these.
§ 3. Experimenting with cords of varying thickness we find that: _the
extension is inversely proportional to the thickness_. If we leave a
weight hanging on a piece of rubber cord (stretched, of course, beyond
its "elastic limit") we find that: _the cord continues to elongate as
long as the weight is left on_. For example: a 1 lb. weight hung on a
piece of rubber cord, 8-1/8 inches long and 1/8 of an inch thick,
stretched it--at first--6¼ inches; after two minutes this had
increased to 6-5/8 (3/8 of an inch more). One hour later 1/8 of an
inch more, and sixteen hours later 1/8 of an inch more, i.e. a sixteen
hours' hang produced an additional extension of ¾ of an inch. On a
thinner cord (half the thickness) same weight produced _an additional
extension_ (_after_ 14 _hours_) _of _10-3/8 _in_.
N.B.--An elastic cord or spring balance should never have a weight
left permanently on it--or be subjected to a distorting force for a
longer time than necessary, or it will take a "permanent set," and not
return to even approximately its original length or form.
In a rubber cord the extension is _directly proportional to the
length_ as well as _inversely proportional to the thickness and to the
weight suspended_--true only within the limits of elasticity.
[Illustration: FIG. 15.--EXTENSION AND INCREASE IN VOLUME.]
§ 4. =When a Rubber Cord is stretched there is an Increase of
Volume.=--On stretching a piece of rubber cord to _twice_ its
original (natural) length, we should perhaps expect to find that the
string would only be _half_ as thick, as would be the case if the
volume remained the same. Performing the experiment, and measuring the
cord as accurately as possible with a micrometer, measuring to the
one-thousandth of an inch, we at once perceive that this is not the
case, being about _two-thirds_ of its former volume.
§ 5. In the case of rubber cord used for a motive power on model
aeroplanes, the rubber is _both_ twisted and stretched, but chiefly
the latter.
Thirty-six strands of rubber, weight about 56 grammes, at 150 turns
give a torque of 4 oz. on a 5-in. arm, but an end thrust, or end pull,
of about 3½ lb. (Ball bearings, or some such device, can be used to
obviate this end thrust when desirable.) A series of experiments
undertaken by the writer on the torque produced by twisted rubber
strands, varying in number, length, etc., and afterwards carefully
plotted out in graph form, have led to some very interesting and
instructive results. Ball bearings were used, and the torque, measured
in eighths of an ounce, was taken (in each case) from an arm 5 in. in
length.
The following are the principal results arrived at. For graphs, see
Fig. 16.
§ 6. A. Increasing the number of (rubber) strands by _one-half_
(length and thickness of rubber remaining constant) increases the
torque (unwinding tendency) _twofold_, i.e., doubles the motive power.
B. _Doubling_ the number of strands increases the torque _more than
three times_--about 3-1/3 times, 3 times up to 100 turns, 3½ times
from 100 to 250 turns.
C. _Trebling_ the number of strands increases the torque at least
_seven times_.
The increased _size_ of the coils, and thereby _increased_ extension,
explains this result. As we increase the number of strands, the
_number_ of twists or turns that can be given it becomes less.
D. _Doubling_ the number of strands (length, etc., remaining
constant) _diminishes_ the number of turns by _one-third to
one-half_. (In few strands one-third, in 30 and over one-half.)
[Illustration: FIG. 16.--TORQUE GRAPHS OF RUBBER MOTORS.
Abscissæ = Turns. Ordinates = Torque measured in 1/16 of an oz.
Length of arm, 5 in.
A. 38 strands of new rubber, 2 ft. 6 in. long; 58 grammes weight.
B. 36 strands, 2 ft. 6 in. long; end thrust at 150 turns, 3½ lb.
C. 32 strands, 2 ft. 6 in. long.
D. 24 " " "
E. 18 " " " weight 28 grammes.
F. 12 " 1 ft. 3 in. long
G. 12 " 2 ft. 6 in. long.]
E. If we halve the length of the rubber strands, keeping the _number_
of strands the same, the torque is but slightly increased for the
first 100 turns; at 240 turns it is double. But the greater number of
turns--in ratio of about 2:1--that can be given the longer strand much
more than compensates for this.
F. No arrangement of the strands, _per se_, gets more energy (more
motive power) out of them than any other, but there are special
reasons for making the strands--
G. As long and as few in number as possible.
1. More turns can be given it.
2. It gives a far more even torque. Twelve strands 2 ft. 6 in. long
give practically a line of small constant angle. Thirty-six strands
same length a much steeper angle, with considerable variations.
A very good result, which the writer has verified in practice, paying
due regard to _both_ propeller and motor, is to make--
H. _The length of the rubber strands twice[13] in feet the number of
the strands in inches_,[14] e.g., if the number of strands is 12 their
length should be 2 ft., if 18, 3 ft., and so on.
§ 7. Experiments with 32 to 38 strands 2 ft. 6 in. long give a torque
curve almost precisely similar to that obtained from experiments made
with flat spiral steel springs, similar to those used in watches and
clocks; and, as we know, the torque given by such springs is very
uneven, and has to be equalised by use of a fusee, or some such
device. In the case of such springs it must not be forgotten that the
turning moment (unwinding tendency) is NOT proportional to the amount
of winding up, this being true only in the "balance" springs of
watches, etc., where _both_ ends of the spring are rigidly fastened.
In the case of SPRING MOTORS.[15]
I. The turning moment (unwinding tendency) is proportional to the
difference between the angle of winding and yielding, proportional to
the moment of inertia of its section, i.e., to the breadth and the
cube of its thickness, also proportional to the modulus of elasticity
of the substance used, and inversely proportional to the length of the
strip.
§ 8. Referring back to A, B, C, there are one or two practical
deductions which should be carefully noted.
Supposing we have a model with one propeller and 36 strands of
elastic. If we decide to fit it with twin screws, then, other reasons
apart, we shall require two sets of strands of more than 18 in number
each to have the same motive power (27 if the same torque be
required).[16] This is an important point, and one not to be lost
sight of when thinking of using two propellers.
Experiments on--
§9. =The Number of Revolutions= (turns) =that can be given to Rubber
Motors= led to interesting results, e.g., the number of turns to
produce a double knot in the cord from end to end were, in the case of
rubber, one yard long:--
No. of Strands. No. of Turns. No. of Strands. No. of Turns.
4 440 16 200
8 310 28 170
12 250
It will be at once noticed that the greater the number of rubber
strands used in a given length, the fewer turns will it stand in
proportion. For instance, 8 strands double knot at 310, and 4 at 440
(and not at 620), 16 at 200, and 8 at 310 (and not 400), and so on.
The reason, of course, is the more the strands the greater the
distance they have to travel round themselves.
§ 10. =The Maximum Number of Turns.=--As to the maximum number of
permissible turns, rubber has rupture stress of 330 lb. per sq. in.,
_but a very high permissible stress_, as much as 80 per cent. The
resilience (power of recovery after distortion) in tension of rubber
is in considerable excess of any other substance, silk being the only
other substance which at all approaches it in this respect, the ratio
being about 11 : 9. The resilience of steel spiral spring is very
slight in comparison.
A rubber motor in which the double knot is not exceeded by more than
100 turns (rubber one yard in length) should last a good time. When
trying for a record flight, using new elastic, as many as even 500 or
600 or even more turns have been given in the case of 32-36 strands a
yard in length; but such a severe strain soon spoils the rubber.
§ 11. =On the Use of "Lubricants."=--One of the drawbacks to rubber is
that if it be excessively strained it soon begins to break up. One of
the chief causes of this is that the strands stick together--they
should always be carefully separated, if necessary, after a
flight--and an undue strain is thereby cast on certain parts. Apart
also from this the various strands are not subject to the same
tension. It has been suggested that if some means could be devised to
prevent this, and allow the strands to slip over one another, a
considerable increase of power might result. It must, however, be
carefully borne in mind that anything of an oily or greasy nature has
an injurious effect on the rubber, and must be avoided at all costs.
Benzol, petroleum, ether, volatile oils, turpentine, chloroform,
naphtha, vaseline, soap, and all kinds of oil must be carefully
avoided, as they soften the rubber, and reduce it more or less to the
consistence of a sticky mass. The only oil which is said to have no
action on rubber, or practically none, is castor oil; all the same, I
do not advise its use as a lubricant.
There are three only which we need consider:--
1. Soda and water.
2. French chalk.
3. Pure redistilled glycerine.
The first is perfectly satisfactory when freshly applied, but soon
dries up and evaporates.
The second falls off; and unless the chalk be of the softest kind,
free from all grit and hard particles, it will soon do more harm than
good.
The third, glycerine, is for ordinary purposes by far the best, and
has a beneficial rather than a deleterious effect on the rubber; but
it must be _pure_. The redistilled kind, free from all traces of
arsenic, grease, etc., is the only kind permissible. It does not
evaporate, and a few drops, comparatively speaking, will lubricate
fifty or sixty yards of rubber.
Being of a sticky or tacky nature it naturally gathers up dust and
particles of dirt in course of time. To prevent these grinding into
the rubber, wash it from time to time in warm soda, and warm and apply
fresh glycerine when required.
Glycerine, unlike vaseline (a product of petroleum), is not a grease;
it is formed from fats by a process known as _saponification_, or
treatment of the oil with caustic alkali, which decomposes the
compound, forming an alkaline stearate (soap), and liberating the
glycerine which remains in solution when the soap is separated by
throwing in common salt. In order to obtain pure glycerine, the fat
can be decomposed by lead oxide, the glycerine remaining in solution,
and the lead soap or plaster being precipitated.
By using glycerine as a lubricant the number of turns that can be
given a rubber motor is greatly increased, and the coils slip over one
another freely and easily, and prevent the throwing of undue strain on
some particular portion, and absolutely prevent the strands from
sticking together.
§ 12. =The Action of Copper upon Rubber.=--Copper, whether in the form
of the metal, the oxides, or the soluble salts, has a marked injurious
action upon rubber.
In the case of metallic copper this action has been attributed to
oxidation induced by the dissolved oxygen in the copper. In working
drawings for model aeroplanes I have noticed designs in which the
hooks on which the rubber strands were to be stretched were made of
_copper_. In no case should the strands be placed upon bare metal. I
always cover mine with a piece of valve tubing, which can easily be
renewed from time to time.
§ 12A. =The Action of Water, etc., on Rubber.=--Rubber is quite
insoluble in water; but it must not be forgotten that it will absorb
about 25 per cent. into its pores after soaking for some time.
Ether, chloroform, carbon-tetrachloride, turpentine, carbon
bi-sulphide, petroleum spirit, benzene and its homologues found in
coal-tar naphtha, dissolve rubber readily. Alcohol is absorbed by
rubber, but is not a solvent of it.
§ 12B. =How to Preserve Rubber.=--In the first place, in order that it
shall be _possible_ to preserve and keep rubber in the best condition
of efficiency, it is absolutely essential that the rubber shall be,
when obtained, fresh and of the best kind. Only the best Para rubber
should be bought; to obtain it fresh it should be got in as large
quantities as possible direct from a manufacturer or reliable rubber
shop. The composition of the best Para rubber is as follows:--Carbon,
87·46 per cent.; hydrogen, 12·00 per cent.; oxygen and ash, 0·54 per
cent.
In order to increase its elasticity the pure rubber has to be
vulcanised before being made into the sheet some sixty or eighty yards
in length, from which the rubber threads are cut; after vulcanization
the substance consists of rubber plus about 3 per cent. of sulphur.
Now, unfortunately, the presence of the sulphur makes the rubber more
prone to atmospheric oxidation. Vulcanized rubber, compared to pure
rubber, has then but a limited life. It is to this process of
oxidation that the more or less rapid deterioration of rubber is due.
To preserve rubber it should be kept from the sun's rays, or, indeed,
any actinic rays, in a cool, airy place, and subjected to as even a
temperature as possible. Great extremes of temperature have a very
injurious effect on rubber, and it should be washed from time to time
in warm soda water. It should be subjected to no tension or
compression.
Deteriorated rubber is absolutely useless for model aeroplanes.
§ 13. =To Test Rubber.=--Good elastic thread composed of pure Para
rubber and sulphur should, if properly made, stretch to seven times
its length, and then return to its original length. It should also
possess a stretching limit at least ten times its original length.
As already stated, the threads or strands are cut from sheets; these
threads can now be cut fifty to the inch. For rubber motors a very
great deal so far as length of life depends on the accuracy and skill
with which the strands are cut. When examined under a microscope (not
too powerful) the strands having the least ragged edge, i.e., the best
cut, are to be preferred.
§ 14. =The Section--Strip or Ribbon versus Square.=--In section the
square and not the ribbon or strip should be used. The edge of the
strip I have always found more ragged under the microscope than the
square. I have also found it less efficient. Theoretically no doubt a
round section would be best, but none such (in small sizes) is on the
market. Models have been fitted with a tubular section, but such
should on no account be used.
§ 15. =Size of the Section.=--One-sixteenth or one-twelfth is the best
size for ordinary models; personally, I prefer the thinner. If more
than a certain number of strands are required to provide the necessary
power, a larger size should be used. It is not easy to say _what_ this
number is, but fifty may probably be taken as an outside limit.
Remember the size increases by area section; twice the _sectional_
height and breadth means four times the rubber.
§ 16. =Geared Rubber Motors.=--It is quite a mistake to suppose that
any advantage can be obtained by using a four to one gearing, say; all
that you do obtain is one-fourth of the power minus the increased
friction, minus the added weight. This presumes, of course, you make
no alteration in your rubber strands.
Gearing such as this means _short_ rubber strands, and such are not to
be desired; in any case, there is the difficulty of increased friction
and added weight to overcome. It is true by splitting up your rubber
motor into two sets of strands instead of one you can obtain more
turns, but, as we have seen, you must increase the number of strands
to get the same thrust, and you have this to counteract any advantage
you gain as well as added weight and friction.
§ 17. The writer has tried endless experiments with all kinds of
geared rubber motors, and the only one worth a moment's consideration
is the following, viz., one in which two gear wheels--same size,
weight, and number of teeth--are made use of, the propeller being
attached to the axle of one of them, and the same number of strands
are used on each axle. The success or non-success of this motor
depends entirely on the method used in its construction. At first
sight it may appear that no great skill is required in the
construction of such a simple piece of apparatus. No greater mistake
could be made. It is absolutely necessary that _the friction and
weight be reduced to a minimum_, and the strength be a maximum. The
torque of the rubber strands on so short an arm is very great.
Ordinary light brass cogwheels will not stand the strain.
A. The cogwheels should be of steel[17] and accurately cut of diameter
sufficient to separate the two strands the requisite distance, _but no
more_.
B. The weight must be a minimum. This is best attained by using solid
wheels, and lightening by drilling and turning.
C. The friction must be a minimum. Use the lightest ball bearings
obtainable (these weigh only 0·3 gramme), adjust the wheels so that
they run with the greatest freedom, but see that the teeth overlap
sufficiently to stand the strain and slight variations in direction
without fear of slipping. Shallow teeth are useless.
D. Use vaseline on the cogs to make them run as easily as possible.
[Illustration: FIG. 17.--GEARED RUBBER MOTOR.
Designed and constructed by the writer. For description of the model,
etc., see Appendix.]
E. The material of the containing framework must be of maximum
strength and minimum lightness. Construct it of minimum size, box
shaped, use the thinnest tin (really tinned sheet-iron) procurable,
and lighten by drilling holes, not too large, all over it. Do not use
aluminium or magnalium. Steel, could it be procured thin enough, would
be better still.
F. Use steel pianoforte wire for the spindles, and hooks for the
rubber strands, using as thin wire as will stand the strain.
Unless these directions are carefully carried out no advantage will be
gained--the writer speaks from experience. The requisite number of
rubber strands to give the best result must be determined by
experiment.
§ 18. One advantage in using such a motor as this is that the two
equal strands untwisting in opposite directions have a decided
steadying effect on the model, similar almost to the case in which two
propellers are used.
The "best" model flights that the writer has achieved have been
obtained with a motor of this description.[18]
In the case of twin screws two such gearings can be used, and the
rubber split up into four strands. The containing framework in this
case can be simply light pieces of tubing let into the wooden
framework, or very light iron pieces fastened thereto.
Do not attempt to split up the rubber into more than two strands to
each propeller.
SECTION II.--OTHER FORMS OF MOTORS.
§ 18A. =Spring Motors.=--This question has already been dealt with
more or less whilst dealing with rubber motors, and the superiority of
the latter over the former pointed out. Rubber has a much greater
superiority over steel or other springs, because in stretch-twisted
rubber far more energy can be stored up weight for weight. One pound
weight of elastic can be made to store up some 320 ft.-lb. of energy,
and steel only some 65 lb. And in addition to this there is the
question of gearing, involving extra weight and friction; that is, if
flat steel springs similar to those used in clockwork mechanism be
made use of, as is generally the case. The only instance in which such
springs are of use is for the purpose of studying the effects of
different distributions of weight on the model, and its effect on the
balance of the machine; but effects such as this can be brought about
without a change of motor.
§ 18B. A more efficient form of spring motor, doing away with gearing
troubles, is to use a long spiral spring (as long as the rubber
strands) made of medium-sized piano wire, similar in principle to
those used in some roller-blinds, but longer and of thinner steel.
The writer has experimented with such, as well as scores of other
forms of spring motors, but none can compare with rubber.
The long spiral form of steel spring is, however, much the best.
§ 18C. =Compressed Air Motors.=--This is a very fascinating form of
motor, on paper, and appears at first sight the ideal form. It is so
easy to write: "Its weight is negligible, and it can be provided free
of cost; all that is necessary is to work a bicycle pump for as many
minutes as the motor is desired to run. This stored-up energy can be
contained in a mere tube, of aluminium or magnalium, forming the
central rib of the machine, and the engine mechanism necessary for
conveying this stored-up energy to the revolving propeller need weigh
only a few ounces." Another writer recommends "a pressure of 300 lb."
§ 18D. A pneumatic drill generally works at about 80 lb. pressure,
and when developing 1 horse-power, uses about 55 cubic ft. of free air
per minute. Now if we apply this to a model aeroplane of average size,
taking a reservoir 3 ft. long by 1½ in. internal diameter, made of
magnalium, say--steel would, of course, be much better--the weight of
which would certainly not be less than 4 oz., we find that at 80 lb.
pressure such a motor would use
55/Horse Power (H.P.)
cub. ft. per minute.
Now 80 lb. is about 5½ atmospheres, and the cubical contents of the
above motor some 63 cub. in. The time during which such a model would
fly depends on the H.P. necessary for flight; but a fair allowance
gives a flight of from 10 to 30 sec. I take 80 lb. pressure as a fair
practical limit.
§ 18E. The pressure in a motor-car tyre runs from 40 to 80 lb.,
usually about 70 lb. Now 260 strokes are required with an ordinary
inflator to obtain so low a pressure as 70 lb., and it is no easy job,
as those who have done it know.
§ 19. Prior to 1893 Mr. Hargraves (of cellular kite fame) studied the
question of compressed-air motors for model flying machines. His motor
was described as a marvel of simplicity and lightness, its cylinder
was made like a common tin can, the cylinder covers cut from sheet tin
and pressed to shape, the piston and junk rings of ebonite.
One of his receivers was 23-3/8 in. long, and 5·5 in. diameter, of
aluminium plate 0·2 in. thick, 3/8 in. by 1/8 in. riveting strips were
insufficient to make tight joints; it weighed 26 oz., and at 80 lb.
water pressure one of the ends blew out, the fracture occurring at the
bend of the flange, and not along the line of rivets. The receiver
which was successful being apparently a tin-iron one; steel tubing was
not to be had at that date in Sydney. With a receiver of this
character, and the engine referred to above, a flight of 343 ft. was
obtained, this flight being the best. (The models constructed by him
were not on the aeroplane, but ornithoptere, or wing-flapping
principle.) The time of flight was 23 _seconds_, with 54½ double
vibrations of the engines. The efficiency of this motor was estimated
to be 29 per cent.
§ 20. By using compressed air, and heating it in its passage to the
cylinder, far greater efficiency can be obtained. Steel cylinders can
be obtained containing air under the enormous pressure of 120
atmospheres.[19] This is practically liquid air. A 20-ft. cylinder
weighs empty 23 lb. The smaller the cylinder the less the
proportionate pressure that it will stand; and supposing a small steel
cylinder, produced of suitable form and weight, and capable of
withstanding with safety a pressure of from 300 to 600 lb. per sq.
in., or from 20 to 40 atmospheres. The most economical way of working
would be to admit the air from the reservoir directly to the motor
cylinders; but this would mean a very great range in the initial
working pressure, entailing not-to-be-thought-of weight in the form of
multi-cylinder compound engines, variable expansion gear, etc.
§ 21. This means relinquishing the advantages of the high initial
pressure, and the passing of the air through a reducing valve, whereby
a constant pressure, say, of 90 to 150, according to circumstances,
could be maintained. By a variation in the ratio of expansion the air
could be worked down to, say, 30 lb.
The initial loss entailed by the use of a reducing valve may be in a
great measure restored by heating the air before using it in the motor
cylinders; by heating it to a temperature of only 320°F., by means of
a suitable burner, the volume of air is increased by one half, the
consumption being reduced in the same proportion; the consumption of
air used in this way being 24 lb. per indicated horse-power per hour.
But this means extra weight in the form of fuel and burners, and what
we gain in one way we lose in another. It is, of course, desirable
that the motor should work at as low a pressure as possible, since as
the store of air is used up the pressure in the reservoir falls, until
it reaches a limit below which it cannot usefully be employed. The air
then remaining is dead and useless, adding only to the weight of the
aeroplane.
§ 22. From calculations made by the writer the _entire_ weight of a
compressed-air model motor plant would be at least _one-third_ the
weight of the aeroplane, and on a small scale probably one-half, and
cannot therefore hold comparison with the _steam engine_ discussed in
the next paragraph. In concluding these remarks on compressed-air
motors, I do not wish to dissuade anyone from trying this form of
motor; but they must not embark on experiments with the idea that
anything useful or anything superior to results obtained with
infinitely less expense by means of rubber can be brought to pass with
a bicycle pump, a bit of magnalium tube, and 60 lb. pressure.
§ 22A. In Tatin's air-compressed motor the reservoir weighed 700
grammes, and had a capacity of 8 litres. It was tested to withstand a
pressure of 20 atmospheres, but was worked only up to seven. The
little engine attached thereto weighed 300 grammes, and developed a
motive power of 2 kilogram-metres per second (_see_ ch. iii.).
§ 23. =Steam-Driven Motors.=--Several successful steam-engined model
aeroplanes have been constructed, the most famous being those of
Professor Langley.
Having constructed over 30 modifications of rubber-driven models, and
experimented with compressed air, carbonic-acid gas, electricity, and
other methods of obtaining energy, he finally settled upon the steam
engine (the petrol motor was not available at that time, 1893). After
many months' work it was found that the weight could not be reduced
below 40 lb., whilst the engine would only develop ½ H.P., and
finally the model was condemned. A second apparatus to be worked by
compressed air was tried, but the power proved insufficient. Then came
another with a carbonic-acid gas engine. Then others with various
applications of electricity and gas, etc., but the steam engine was
found most suitable; yet it seemed to become more and more doubtful
whether it could ever be made sufficiently light, and whether the
desired end could be attained at all. The chief obstacle proved not to
be with the engines, which were made surprisingly light after
sufficient experiment. _The great difficulty was to make a boiler of
almost no weight which would give steam enough._
§ 24. At last a satisfactory boiler and engine were produced.
The engine was of 1 to 1½ H.P., total weight (including moving
parts) 26 oz. The cylinders, two in number, had each a diameter of
1¼ in., and piston stroke 2 in.
The boiler, with its firegrate, weighed a little over 5 lb. It
consisted of a continuous helix of copper tubing, 3/8 in. external
diameter, the diameter of the coil being 3 in. altogether. Through the
centre of this was driven the blast from an "Ælopile," a modification
of the naphtha blow-torch used by plumbers, the flame of which is
about 2000° F.[20] The pressure of steam issuing into the engines
varied from 100 to 150 lb. per sq. in.; 4 lb. weight of water and
about 10 oz. of naphtha could be carried. The boiler evaporated 1 lb.
of water per minute.
The twin propellers, 39 in. in diam., pitch 1¼, revolved from 800
to 1000 a minute. The entire aeroplane was 15 ft. in length, the
aerofoils from tip to tip about 14 ft., and the total weight slightly
less than 30 lb., of which _one-fourth was contained in the
machinery_. Its flight was a little over half a mile in length, and of
1½ minutes' duration. Another model flew for about three-quarters
of a mile, at a rate of about 30 miles an hour.
It will be noted that engine, generator, etc., work out at about 7 lb.
per H.P. Considerable advance has been made in the construction of
light and powerful model steam engines since Langley's time, chiefly
in connexion with model hydroplanes, and a pressure of from 500 to 600
lb. per sq. in. has been employed; the steam turbine has been brought
to a high state of perfection, and it is now possible to make a model
De Laval turbine of considerable power weighing almost next to
nothing,[21] the real trouble, in fact the only one, being the steam
generator. An economization of weight means a waste of steam, of which
models can easily spend their only weight in five minutes.
§ 25. One way to economize without increased weight in the shape of a
condenser is to use spirit (methylated spirit, for instance) for both
fuel and boiler, and cause the exhaust from the engines to be ejected
on to the burning spirit, where it itself serves as fuel. By using
spirit, or some very volatile hydrocarbon, instead of water, we have a
further advantage from the fact that such vaporize at a much lower
temperature than water.
§ 26. When experimenting with an engine of the turbine type we must
use a propeller of small diameter and pitch, owing to the very high
velocity at which such engines run.
Anyone, however, who is not an expert on such matters would do well to
leave such motors alone, as the very highest technical skill, combined
with many preliminary disappointments and trials, are sure to be
encountered before success is attained.
§ 27. And the smaller the model the more difficult the problem--halve
your aeroplane, and your difficulties increase anything from fourfold
to tenfold.
The boiler would in any case be of the flash type of either copper or
steel tubing (the former for safety), with a magnalium container for
the spirit, and a working pressure of from 150 to 200 lb. per sq. in.
Anything less than this would not be worth consideration.
§ 28. Some ten months after Professor Langley's successful model
flights (1896), experiments were made in France at Carquenez, near
Toulon. The total weight of the model aeroplane in this case was 70
lb.; the engine power a little more than 1 H.P. Twin screws were
used--_one in front and one behind_. The maximum velocity obtained was
40 miles per hour; but the length of run only 154 yards, and duration
of flight only a few seconds. This result compares very poorly with
Langley's distance (of best flight), nearly one mile, duration 1 min.
45 sec. The maximum velocity was greater--30 to 40 miles per hour. The
total breadth of this large model was rather more than 6 metres, and
the surface a little more than 8 sq. metres.
§ 29. =Petrol Motors.=--Here it would appear at first thought is the
true solution of the problem of the model aeroplane motor. Such a
motor has solved the problem of aerial locomotion, as the steam engine
solved that of terrestrial and marine travel, both full sized and
model; and if in the case of full sized machines, then why not models.
[Illustration: FIG. 18.--MR. STANGER'S MODEL IN FULL FLIGHT.]
[Illustration: FIG. 19.--MR. STANGER'S PETROL-DRIVEN MODEL AEROPLANE.
(_Illustrations by permission from electros supplied by the "Aero."_)]
§ 30. The exact size of the smallest _working_ model steam engine that
has been made I do not know,[22] but it is or could be surprisingly
small; not so the petrol motor--not one, that is, that would _work_.
The number of petrol motor-driven model aeroplanes that have actually
flown is very small. Personally I only know of one, viz., Mr. D.
Stanger's, exhibited at the aero exhibition at the Agricultural Hall
in 1908.
[Illustration: FIG. 20.--MR. STANGER'S MODEL PETROL ENGINE.]
[Illustration: FIG. 21.--MR. STANGER'S MODEL PETROL ENGINE.]
In Fig. 21 the motor is in position on the aeroplane. Note
small carburettor. In Fig. 20 an idea of the size of engine may
be gathered by comparing it with the ordinary sparking-plug
seen by the side, whilst to the left of this is one of the
special plugs used on this motor. (_Illustrations by permission
from electros supplied by the "Aero."_)
§ 31. The following are the chief particulars of this interesting
machine:--The engine is a four-cylinder one, and weighs (complete with
double carburetter and petrol tank) 5½ lb., and develops 1¼ H.P.
at 1300 revolutions per minute.
[Illustration: FIG. 22.--ONE-CYLINDER PETROL MOTOR.
(_Electro from Messrs. A.W. Gamage's Aviation Catalogue._)]
The propeller, 29 in. in diam. and 36 in. in pitch, gives a static
thrust of about 7 lb. The machine has a spread of 8 ft. 2 in., and is
6 ft. 10 in. in length. Total weight 21 lb. Rises from the ground when
a speed of about 16 miles an hour is attained. A clockwork
arrangement automatically stops the engine. The engine air-cooled. The
cylinder of steel, cast-iron heads, aluminium crank-case, double float
feed carburetter, ignition by single coil and distributor. The
aeroplane being 7 ft. 6 in. long, and having a span 8 ft.
§ 32. =One-cylinder Petrol Motors.=--So far as the writer is aware no
success has as yet attended the use of a single-cylinder petrol motor
on a model aeroplane. Undoubtedly the vibration is excessive; but this
should not be an insuperable difficulty. It is true it is heavier in
proportion than a two-cylinder one, and not so efficient; and so far
has not proved successful. The question of vibration on a model
aeroplane is one of considerable importance. A badly balanced
propeller even will seriously interfere with and often greatly curtail
the length of flight.
§ 33. =Electric Motors.=--No attempt should on any account be made to
use electric motors for model aeroplanes. They are altogether too
heavy, apart even from the accumulator or source of electric energy,
for the power derivable from them. To take an extreme case, and
supposing we use a 2-oz. electric motor capable of driving a propeller
giving a static thrust of 3 oz.,[23] on weighing one of the smallest
size accumulators without case, etc., I find its weight is 4½ oz.
One would, of course, be of no use; at least three would be required,
and they would require practically short circuiting to give sufficient
amperage (running them down, that is, in some 10 to 15 seconds). Total
weight, 1 lb. nearly. Now from a _pound_ weight of rubber one could
obtain a thrust of _pounds_, not ounces. For scale models not intended
for actual flight, of course, electric motors have their uses.
FOOTNOTES:
[12] Also there is no necessity for gearing.
[13] In his latest models the writer uses strands even three times and
not twice as long, viz. fourteen strands 43 in. long.
[14] This refers to 1/16 in. square sectioned rubber.
[15] Of uniform breadth and thickness.
[16] In practice I find not quite so high a proportion as this is
always necessary.
[17] Steel pinion wire is very suitable.
[18] See Appendix.
[19] As high a pressure as 250 atmospheres has been used.
[20] There was a special pump keeping the water circulating rapidly
through the boiler, the intense heat converting some of it into steam
as it flowed. The making of this boiler alone consumed months of work;
the entire machine taking a year to construct, with the best
mechanical help available.
[21] Model Steam Turbines. "Model Engineer" Series, No. 13, price
6_d._
[22] See Introduction, note to § 1.
[23] The voltage, etc., is not stated.
CHAPTER V.
PROPELLERS OR SCREWS.
§ 1. The design and construction of propellers, more especially the
former, is without doubt one of the most difficult parts of model
aeroplaning.
With elastic or spring driven models the problem is more complicated
than for models driven by petrol or some vaporized form of liquid
fuel; and less reliable information is to hand. The problem of
_weight_, unfortunately, is of primary importance.
We will deal with these points in due course; to begin with let us
take:--
THE POSITION OF THE PROPELLER.
In model aeroplanes the propeller is usually situated either in front
or in the rear of the model; in the former case it is called a TRACTOR
SCREW, i.e., it pulls instead of pushes.
As to the merits of the two systems with respect to the tractor, there
is, we know, in the case of models moving through water a distinct
advantage in placing the propeller behind, and using a pushing or
propulsive action, on account of the frictional "wake" created behind
the boat, and which causes the water to flow after the vessel, but at
a lesser velocity.
In placing the propeller behind, we place it in such a position as to
act upon and make use of this phenomenon, the effect of the propeller
being to bring this following wake to rest. Theoretically a boat,
model or otherwise, can be propelled with less horse-power than it can
be towed. But with respect to aeroplanes, apart altogether from the
difference of medium, there is _at present_ a very considerable
difference of _form_, an aeroplane, model or otherwise, bearing at
present but little resemblance to the hull of a boat.
Undoubtedly there is a frictional wake in the case of aeroplanes,
possibly quite as much in proportion as in the case of a boat,
allowing for difference of medium. Admitting, then, that this wake
does exist, it follows that a propulsive screw is better than a
tractor. In a matter of this kind constructional considerations, or
"ease of launching," and "ability to land without damage," must be
given due weight.
In the case of model aeroplanes constructional details incline the
balance neither one way nor the other; but "ease in launching" and
"ability to land without damage" weigh the balance down most decidedly
in favour of a driving or propulsive screw.
In the case of full-sized monoplanes constructional details had most
to do with the use of tractors; but monoplanes are now being built
with propulsive screws.[24]
In the case of models, not models of full-sized machines, but actual
model flyers, the writer considers propulsive screws much the
best.[25]
In no case should the propeller be placed in the centre of the model,
or in such a position as to _shorten the strands of the elastic
motor_, if good flights are desired.
In the case of petrol or similar driven models the position of the
propeller can be safely copied from actual well-recognised and
successful full-sized machines.
§ 2. =The Number of Blades.=--Theoretically the number of blades does
not enter into consideration. The mass of air dealt with by the
propeller is represented by a cylinder of indefinite length, whose
diameter is the same as that of the screw, and the rate at which this
cylinder is projected to the rear depends theoretically upon the pitch
and revolutions (per minute, say) of the propeller and not the number
of blades. Theoretically one blade (helix incomplete) would be
sufficient, but such a screw would not "balance," and balance is of
primary importance; the minimum number of blades which can be used is
therefore _two_.
In marine models three blades are considered best, as giving a better
balance.
In the case of their aerial prototypes the question of _weight_ has
again to be considered, and two blades is practically the invariable
custom.[26] Here, again, constructional considerations again come to
the fore, and in the case of wooden propellers one of two blades is of
far more easy construction than one of three.
By increasing the number of blades the "thrust" is, of course, more
evenly distributed over a larger area, but the weight is considerably
increased, and in models a greater advantage is gained by keeping down
the weight than might follow from the use of more blades.
§ 3. =Fan versus Propeller.=--It must always be most carefully borne
in mind that a fan (ventilating) and a propeller are not the same
thing. Because many blades are found in practice to be efficient in
the case of the former, it is quite wrong to assume that the same
conclusion holds in the case of the latter.
By increasing the number of blades the skin friction due to the
resistance that has to be overcome in rotating the propeller through
the air is added to.
Moreover a fan is stationary, whilst a propeller is constantly
_advancing_ as well as _rotating_ through the air.
The action of a fan blower is to move a small quantity of air at a
high velocity; whereas the action of a propeller is, or should be, to
move _a large quantity of air at a small velocity_, for the function
of a screw is to create thrust. Operating on a yielding fluid medium
this thrust will evidently be in proportion to the mass of fluid
moved, and also to the velocity at which it is put in motion.
But the power consumed in putting this mass of fluid in motion is
proportional to the mass and to the _square_ of the velocity at which
it moves. From this it follows, as stated above, that in order to
obtain a given thrust with the least loss of power, the mass of fluid
acted on should be as large as possible, and the velocity imparted to
it as little as possible.
A fan requires to be so designed as to create a thrust when stationary
(static thrust), and a propeller whilst moving through the air
(dynamic thrust).
§ 4. =The Function of a Propeller= is to produce dynamic thrust; and
the great advantage of the use of a propeller as a thrusting or
propulsive agent is that its surface is always active. It has no
_dead_ points, and its motion is continuous and not reciprocating, and
it requires no special machinery or moving parts in its construction
and operation.
§ 5. =The Pitch= of a propeller or screw is the linear distance a
screw moves, backwards or forwards, in one complete revolution. This
distance is purely a theoretical one. When, for instance, a screw is
said to have a pitch of 1 ft., or 12 in., it means that the model
would advance 1 ft. through the air for each revolution of the screw,
provided that the propeller blade were mounted in _solid_ guides, like
a nut on a bolt with one thread per foot. In a yielding fluid such as
water or air it does not practically advance this distance, and hence
occurs what is known as--
§ 6. =Slip=, which may be defined as the distance which ought to be
traversed, but which is lost through imperfections in the propelling
mechanism; or it may be considered as power which should have been
used in driving the model forward. In the case of a locomotive running
on dry rails nothing is lost in slip, there being none. In the case of
a steamer moored and her engines set going, or of an aeroplane held
back prior to starting, all the power is used in slip, i.e. in putting
the fluid in motion, and none is used in propulsion.
Supposing the propeller on our model has a pitch of 1 ft., and we give
the elastic motor 100 turns, theoretically the model should travel 100
ft. in calm air before the propeller is run down; no propeller yet
designed will do this. Supposing the actual length 77 ft., 23 per
cent. has been lost in "slip." For this to be actually correct the
propeller must stop at the precise instant when the machine comes to
ground.
Taking "slip" into account, then--
_The speed of the model in feet per minute = pitch (in feet) ×
revolutions per minute -- slip (feet per minute)._
This slip wants to be made small--just how small is not yet known.
If made too small then the propeller will not be so efficient, or, at
any rate, such is the conclusion come to in marine propulsion, where
it is found for the most economical results to be obtained that the
slip should be from 10 to 20 per cent.
In the case of aerial propellers a slip of 25 per cent. is quite good,
40 per cent. bad; and there are certain reasons for assuming that
possibly about 15 per cent. may be the best.
§ 7. It is true that slip represents energy lost; but some slip is
essential, because without slip there could be no "thrust," this same
thrust being derived from the reaction of the volume of air driven
backwards.
The thrust is equal to--
_Weight of mass of air acted on per second × slip velocity in feet per
second._
In the case of an aeroplane advancing through the air it might be
thought that the thrust would be less. Sir Hiram Maxim found, however,
as the result of his experiments that the thrust with a propeller
travelling through the air at a velocity of 40 miles an hour was the
same as when stationary, the r.p.m. remaining constant throughout. The
explanation is that when travelling the propeller is continually
advancing on to "undisturbed" air, the "slip" velocity is reduced, but
the undisturbed air is equivalent to acting upon a greater mass of
air.
§ 8. =Pitch Coefficient or Pitch Ratio.=--If we divide the pitch of a
screw by its diameter we obtain what is known as pitch coefficient or
ratio.
The mean value of eighteen pitch coefficients of well-known full-sized
machines works out at 0·62, which, as it so happens, is exactly the
same as the case of the Farman machine propeller considered alone,
this ratio varying from 0·4 to 1·2; in the case of the Wright's
machine it is (probably) 1. The efficiency of their propeller is
admitted on all hands. Their propeller is, of course, a slow-speed
propeller, 450 r.p.m. The one on the Blériot monoplane (Blériot XI.)
pitch ratio 0·4, r.p.m. 1350.
In marine propulsion the pitch ratio is generally 1·3 for a slow-speed
propeller, decreasing to 0·9 for a high-speed one. In the case of
rubber-driven model aeroplanes the pitch ratio is often carried much
higher, even to over 3.
Mr. T.W.K. Clarke recommends a pitch angle of 45°, or less, at the
tips, and a pitch ratio of 3-1/7 (with an angle of 45°). Within limits
the higher the pitch ratio the better the efficiency. The higher the
pitch ratio the slower may be the rate of revolution. Now in a rubber
motor we do not want the rubber to untwist (run out) too quickly; with
too fine a pitch the propeller "races," or does something remarkably
like it. It certainly revolves with an abnormally high percentage of
slip. And for efficiency it is certainly desirable to push this ratio
to its limit; but there is also the question of the
§ 9. =Diameter.=--"The diameter (says Mr. T.W.K. Clarke) should be
equal to one-quarter the span of the machine."
If we increase the diameter we shall decrease the pitch ratio. From
experiments which the writer has made he prefers a lower pitch ratio
and increased diameter, viz. a pitch ratio of 1·5, and a diameter of
one-third to even one-half the span, or even more.[27] Certainly not
less than one-third. Some model makers indulge in a large pitch ratio,
angle, diameter, and blade area as well, but such a course is not to
be recommended.
§ 10. =Theoretical Pitch.=--Theoretically the pitch (from boss to
tip) should at all points be the same; the boss or centre of the blade
at right angles to the plane of rotation, and the angle decreasing as
one approaches the tips. This is obvious when one considers that the
whole blade has to move forward the same amount. In the diagrams Figs.
23 and 24 the tip A of the propeller travels a distance = 2 {pi} R every
revolution. At a point D on the blade, distant _r_ from the centre,
the distance is 2 {pi} _r_. In both instances the two points must advance
a distance equal to the pitch, i.e. the distance represented by P O.
[Illustration: FIG. 23.]
[Illustration: FIG. 24.
A O = 2 {pi} R; D O = 2 {pi} _r_.]
A will move along A P, B along B P, and so on. The angles at the
points A, B, C ... (Fig. 24), showing the angles at which the
corresponding parts of the blade at A, B, C ... in Fig. 23 must be set
in order that a uniform pitch may be obtained.
§ 11. If the pitch be not uniform then there will be some portions of
the blade which will drag through the air instead of affording useful
thrust, and others which will be doing more than they ought, putting
air in motion which had better be left quiet. This uniform total pitch
for all parts of the propeller is (as already stated) a decreasing
rate of pitch from the centre to the edge. With a total pitch of 5
ft., and a radius of 4 ft., and an angle at the circumference of 6°,
then the angle of pitch at a point midway between centre and
circumference should be 12°, in order that the total pitch may be the
same at all parts.
§ 12. =To Ascertain the Pitch of a Propeller.=--Take any point on one
of the blades, and carefully measure the inclination of the blade at
that point to the plane of rotation.
If the angle so formed be about 19° (19·45),[28] i.e., 1 in 3, and the
point 5 in. from the centre, then every revolution this point will
travel a distance
2 {pi} _r_ = 2 × 22/7 × 5 = 31·34.
Now since the inclination is 1 in 3,[29] the propeller will travel
forward theoretically one-third of this distance, or
31·43/3 = 10·48 = 10½ in. approx.
Similarly any other case may be dealt with. If the propeller have a
uniform _constant angle_ instead of a uniform pitch, then the pitch
may be calculated at a point about one-third the length of the blade
from the tip.
§ 13. =Hollow-Faced Blades.=[30]--It must always be carefully borne
in mind that a propeller is nothing more nor less than a particular
form of aeroplane specially designed to travel a helical path. It
should, therefore, be hollow faced and partake of the "stream line"
form, a condition not fulfilled if the face of the blade be flat--such
a surface cutting into the air with considerable shock, and by no
means creating as little undesirable motion in the surrounding medium
as possible.
It must not be forgotten that a curved face blade has of necessity an
increasing pitch from the cutting to the trailing edge (considering,
of course, any particular section). In such a case the pitch is the
_mean effective pitch_.
§ 14. =Blade Area.=--We have already referred to the fact that the
function of a propeller is to produce dynamic thrust--to drive the
aeroplane forward by driving the air backwards. At the same time it is
most desirable for efficiency that the air should be set in motion as
little as possible, this being so much power wasted; to obtain the
greatest reaction or thrust the greatest possible volume of air should
be accelerated to the smallest velocity.
In marine engineering in slow-speed propellers (where cavitation[31]
does not come in) narrow blades are usually used. In high-speed marine
propellers (where cavitation is liable to occur) the projected area of
the blades is sometimes as much as 0·6 of the total disk area. In the
case of aerial propellers, where cavitation does not occur, or not
unless the velocity be a very high one (1500 or more a minute), narrow
blades are the best. Experiments in marine propulsion also show that
the thrust depends more on the disk area than on the width of the
blades. All the facts tend to show that for efficiency the blades of
the propeller should be narrow, in order that the air may not be acted
on for too long a time, and so put too much in motion, and the blades
be so separated that one blade does not disturb the molecules of air
upon which the next following one must act. Both in the case of marine
and aerial propellers multiplicity of blades (i.e. increased blade
area) tends to inefficiency of action, apart altogether from the
question of weight and constructional difficulties. The question of
increasing pitch in the case of hollow-faced blades, considered in the
last paragraph, has a very important bearing on the point we are
considering. To make a wide blade under such circumstances would be to
soon obtain an excessive angle.
In the case of a flat blade the same result holds, because the air has
by the contact of its molecules with the "initial minimum width" been
already accelerated up to its final velocity, and further area is not
only wasted, but inimical to good flights, being our old bugbear
"weight in excess."
Requisite strength and stiffness, of course, set a limit on the final
narrowness of the blades, apart from other considerations.
§ 15. The velocity with which the propeller is rotated has also an
important bearing on this point; but a higher speed than 900 r.p.m.
does not appear desirable, and even 700 or less is generally
preferable.[32] In case of twin-screw propellers, with an angle at the
tips of 40° to 45°, as low a velocity of 500 or even less would be
still better.[33]
§ 16. =Shrouding.=--No improvement whatever is obtained by the use of
any kind of shrouding or ring round the propeller tips, or by
corrugating the surface of the propeller, or by using cylindrical or
cone-shaped propeller chamber or any kind of air guide either before
or after the propeller; allow it to revolve in as free an air-feed as
possible, the air does not fly off under centrifugal force, but is
powerfully sucked inwards in a well-designed propeller.
[Illustration: FIG. 25.
A TUBE OF AIR.]
[Illustration: FIG. 26.
A CYLINDER OF AIR.]
§ 17. =General Design.=--The propeller should be so constructed as to
act upon a tube and not a "cylinder" of air. Many flying toys
(especially the French ones) are constructed with propellers of the
cylinder type. Ease of manufacture and the contention that those
portions of the blades adjacent to the boss do little work, and a
slight saving in weight, are arguments that can be urged in their
favour. But all the central cut away part offers resistance in the
line of travel, instead of exerting its proportionate propulsive
power, and their efficiency is affected by such a practice.
§ 18. A good =Shape= for the blades[34] is rectangular with rounded
corners; the radius of the circle for rounding off the corners may be
taken as about one-quarter of the width of the blade. The shape is not
_truly rectangular, for the width of this rectangular at (near) the
boss should be one-half the width at the tip_.
The thickness should diminish uniformly from the boss to the tip. (In
models the thickness should be as little as is consistent with
strength to keep down the weight). _The pitch uniform and large._
[Illustration: FIG. 27.--O T = 1/3 O P.]
§ 19. =The Blades, two in number=, and hollow faced--the maximum
concavity being one-third the distance from the entering to the
trailing edge; the ratio of A T to O P (the width) being 0·048 or 1 :
21, these latter considerations being founded on the analogy between a
propeller and the aerofoil surface. (If the thickness be varied from
the entering to the trailing edge the greatest thickness should be
towards the former.) The convex surface of the propeller must be taken
into account, in fact, it is no less important than the concave, and
the entire surface must be given a true "stream line" form.
[Illustration: FIG. 28.]
[Illustration: FIG. 29.]
If the entering and trailing edge be not both straight, but one be
curved as in Fig. 28, then the straight edge must be made the
_trailing_ edge. And if both be curved as in Fig. 29, then the
_concave_ edge must be the trailing edge.
§ 19. =Propeller Design.=--To design a propeller, proceed as follows.
Suppose the diameter 14 in. and the pitch three times the diameter,
i.e. 52 in. (See Fig. 30.)
Take one-quarter scale, say. Draw a centre line A B of convenient
length, set of half the pitch 52 in. -- ¼ scale = 5¼ in. = C - D.
Draw lines through C and D at right angles to C D.
With a radius equal to half the diameter (i.e. in this case 1¾ in.)
of the propeller, describe a semicircle E B F and complete the
parallelogram F H G E. Divide the semicircle into a number of equal
parts; twelve is a convenient number to take, then each division
subtends an angle of 15° at the centre D.
Divide one of the sides E G into the same number of equal parts
(twelve) as shown. Through these points draw lines parallel to F E or
H G.
And through the twelve points of division on the semicircle draw lines
parallel to F H or E G as shown. The line drawn through the successive
intersections of these lines is the path of the tip of the blade
through half a revolution, viz. the line H S O T E.
S O T X gives the angle at the tip of the blades = 44°.
Let the shape of the blade be rectangular with rounded corners, and
let the breadth at the tip be twice that at the boss.
Then the area (neglecting the rounded off corners) is 10½ sq. in.
[Illustration: FIG. 30.--PROPELLER DESIGN.
One quarter scale. Diameter 14 in. Pitch 52 in. Angle at tip 44°.]
The area being that of a rectangle 7 in. × 1 in. = 7 sq. in. plus area
of two triangles, base ½ in., height 7 in. Now area of triangle =
half base × height. Therefore area of both triangles = ½ in. × 7
in. = 3½ sq. in. Now the area of the disc swept out by the
propeller is
{pi}/4 × (diam.)² ({pi} = 22/7)
[Illustration: FIG. 31.--PROPELLER DESIGN.
Scale one-eighth for A B and B C; but sections of blade are
full-sized.]
And if _d_ A _r_ = the "disc area ratio" we have
(_d_ A _r_) × {pi}/4 × (14)² = area of blade = 10½,
whence _d_ A _r_ = 0·07 about.
[Illustration: FIG. 32.]
[Illustration: FIG. 33.]
In Fig. 31 set off A B equal to the pitch of the propeller (42 in.),
one-eighth scale. Set off B C at right angles to A B and equal to
{pi} × diameter = 22/7 × 14 = 44 in. to scale 5½ in.
Divide B C into a convenient number of equal parts in the figure; five
only are taken, D, E, F, G, H; join A D, A E, A F, A G, A H and
produce them; mark off distances P O, S R, Y T ... equal to the width
of the blade at these points (H P = H O; G S = G R ...) and sketch in
the sections of blade as desired. In the figure the greatest concavity
of the blade is supposed to be one-third the distances P O, S R ...
from PS.... The concavity is somewhat exaggerated. The angles A H B, A
G B, A F B ... represent the pitch angle at the points H, G, F ... of
the blade.
Similarly any other design may be dealt with; in a propeller of 14 in.
diameter the diameter of the "boss" should not be more than 10/16 in.
§ 20. =Experiments with Propellers.=--The propeller design shown in
Figs. 32 and 33, due to Mr. G. de Havilland,[35] is one very suitable
for experimental purposes. A single tube passing through a T-shaped
boss forms the arms. On the back of the metal blade are riveted four
metallic clips; these clips being tightened round the arm by
countersunk screws in the face of the blade.
The tube and clips, etc., are all contained with the back covering of
the blade, as shown in Fig. 35, if desired, the blade then practically
resembling a wooden propeller. The construction, it will be noticed,
allows of the blade being set at any angle, constant or otherwise;
also the pitch can be constant or variable as desired, and any "shape"
of propeller can be fitted.
The advantage of being able to _twist_ the blade (within limits) on
the axis is one not to be underestimated in experimental work.
[Illustration: FIG. 34.--THE AUTHOR'S PROPELLER TESTING APPARATUS.]
With a view to ascertain some practical and reliable data with respect
to the _dynamic_, or actual thrust given when moving through free air
at the velocity of actual travel, the author experimented with the
apparatus illustrated in Figs. 34 and 35, which is so simple and
obvious as to require scarcely any explanation.
The wires were of steel, length not quite 150 ft., fitted with wire
strainers for equalising tension, and absolutely free from "kinks."
As shown most plainly in Fig. 35, there were two parallel wires
sufficiently far apart for the action of one propeller not to affect
the other. Calling these two wires A and B, and two propellers _x_ and
_y_, then _x_ is first tried on A and _y_ on B. Results carefully
noted.
[Illustration: FIG. 35.--PROPELLER TESTING.
Showing distance separating the two wires.]
Then _x_ is tried on B and _y_ on A, and the results again carefully
noted. If the results confirm one another, the power used in both
cases being the same, well and good; if not, adjustments, etc., are
made in the apparatus until satisfactory results are obtained. This
was done when the propellers "raced" one against the other. At other
times one wire only was made use of, and the time and distance
traversed was noted in each case. Propellers were driven through
smoke, and with silk threads tied to a light framework slightly larger
than their disc area circumference. Results of great interest were
arrived at. These results have been assumed in much that has been said
in the foregoing paragraphs.
[Illustration: FIG. 36.--ONE GROUP OF PROPELLERS TESTED BY THE AUTHOR.]
Briefly put, these results showed:--
1. The inefficiency of a propeller of the fan blower or of the static
thrust type.
2. The advantage of using propellers having hollow-faced blades and
large diameter.
3. That diameter was more useful than blade area, i.e. given a certain
quantity (weight) of wood, make a long thin blade and not a shorter
one of more blade area--blade area, i.e., as proportionate to its
corresponding disc area.
4. That the propeller surface should be of true stream-line form.
5. That it should act on a cylinder and not tubes of air.
6. That a correctly designed and proportioned propeller was just as
efficacious in a small size of 9 in. to 28 in. as a full-sized
propeller on a full-sized machine.
[Illustration: FIG. 37.--AN EFFICIENT PROPELLER, BUT RATHER HEAVY.
Ball bearings, old and new. Note difference in sizes and weights.
Propeller, 14 in. diam.; weight 36 grammes.]
A propeller of the static-thrust type was, of course, "first off,"
sometimes 10 ft. or 12 ft. ahead, or even more; but the correctly
designed propeller gradually gathered up speed and acceleration, just
as the other fell off and lost it, and finally the "dynamic" finished
along its corresponding wire far ahead of the "static," sometimes
twice as far, sometimes six times. "Freak" propellers were simply not
in it.
[Illustration: FIG. 38.--"VENNA" PROPELLER.
A 20 per cent. more efficient propeller than that shown in Fig. 41; 14
per cent. lighter; 6 per cent. better in dynamic thrust--14 in. diam.;
weight 31 grammes.]
Metal propellers of constant angle, as well as wooden ones of uniform
(constant) pitch, were tested; the former gave good results, but not
so good as the latter.
The best angle of pitch (at the tip) was found to be from 20° to 30°.
In all cases when the slip was as low as 25 per cent., or even
somewhat less, nearly 20 per cent., a distinct "back current" of air
was given out by the screw. This "slip stream," as it is caused, is
absolutely necessary for efficiency.
§ 21. =Fabric-covered= screws did not give very efficient results; the
only point in their use on model aeroplanes is their extreme
lightness. Two such propellers of 6 in. diameter can be made to weigh
less than 1/5 oz. the pair; but wooden propellers (built-up principle)
have been made 5 in. diameter and 1/12 oz. in weight.
§ 22. Further experiments were made with twin screws mounted on model
aeroplanes. In one case two propellers, both turning in the _same_
direction, were mounted (without any compensatory adjustment for
torque) on a model, total weight 1½ lb. Diameter of each propeller
14 in.; angle of blade at tip 25°. The result was several good
flights--the model (_see_ Fig. 49c) was slightly unsteady across the
wind, that was all.
In another experiment two propellers of same diameter, pitch, etc.,
but of shape similar to those shown in Figs. 28 and 29, were tried as
twin propellers on the same machine. The rubber motors were of equal
weight and strength.
The model described circled to the right or left according to the
position of the curved-shaped propeller, whether on the left or right
hand, thereby showing its superiority in dynamic thrust. Various
alterations were made, but always with the same result. These
experiments have since been confirmed, and there seems no doubt that
the double-curved shaped blade _is_ superior. (See Fig. 39.)
§ 23. =The Fleming-Williams Propeller.=--A chapter on propellers would
scarcely be complete without a reference to the propeller used on a
machine claiming a record of over a quarter of a mile. This form of
propeller, shown in the group in Fig. 36 (top right hand), was found
by the writer to be extremely deficient in dynamic thrust, giving the
worst result of any shown there.
[Illustration: FIG. 39.--CURVED DOUBLE PROPELLER.
The most efficient type yet tested by the writer, when the blade is
made hollow-faced. When given to the writer to test it was flat-faced
on one side.]
[Illustration: FIG. 40.--THE FLEMING-WILLIAMS MODEL.]
It possesses large blade area, large pitch angle--more than 45° at the
tip--and large diameter. These do not combine to propeller efficiency
or to efficient dynamic thrust; but they do, of course, combine to
give the propeller a very slow rotational velocity. Provided they give
_sufficient_ thrust to cause the model to move through the air at a
velocity capable of sustaining it, a long flight may result, not
really owing to true efficiency on the part of the propellers,[36] but
owing to the check placed on their revolutions per minute by their
abnormal pitch angle, etc. The amount of rubber used is very great for
a 10 oz. model, namely, 34 strands of 1/16 in. square rubber to each
propeller, i.e. 68 strands in all.
[Illustration: FIG. 41.--THE SAME IN FLIGHT.
(_Reproduced by permission from "The Aero."_)]
On the score of efficiency, when it is desired to make a limited
number of turns give the longest flight (which is the problem one
always has to face when using a rubber motor) it is better to make use
of an abnormal diameter, say, more than half the span, and using a tip
pitch angle of 25°, than to make use of an abnormal tip pitch 45° and
more, and large blade area. In a large pitch angle so much energy is
wasted, not in dynamic thrust, but in transverse upsetting torque. On
no propeller out of dozens and dozens that I have tested have I ever
found a tip-pitch of more than 35° give a good dynamic thrust; and for
length of flight velocity due to dynamic thrust must be given due
weight, as well as the duration of running down of the rubber motor.
§ 24. Of built up or carved out and twisted wooden propellers, the
former give the better result; the latter have an advantage, however,
in sometimes weighing less.
FOOTNOTES:
[24] _Note._--Since the above was written some really remarkable
flights have been obtained with a 1 oz. model having two screws, one
in front and the other behind. Equally good flights have also been
obtained with the two propellers behind, one revolving in the
immediate rear of the other. Flying, of course, with the wind,
_weight_ is of paramount importance in these little models, and in
both these cases the "single stick" can be made use of. _See also_ ch.
iv., § 28.
[25] _See also_ ch. viii., § 5.
[26] Save in case of some models with fabric-covered propellers. Some
dirigibles are now being fitted with four-bladed wooden screws.
[27] Vide Appendix.
[28] Vide Equivalent Inclinations--Table of.
[29] One in 3 or 0·333 is the _sine_ of the angle; similarly if the
angle were 30° the sine would be 0·5 or ½, and the theoretical
distance travelled one-half.
[30] _Flat-Faced Blades._--If the blade be not hollow-faced--and we
consider the screw as an inclined plane and apply the Duchemin formula
to it--the velocity remaining the same, the angle of maximum thrust is
35¼°. Experiments made with such screws confirm this.
[31] Cavitation is when the high speed of the screw causes it to carry
round a certain amount of the medium with it, so that the blades
strike no undisturbed, or "solid," air at all, with a proportionate
decrease in thrust.
[32] In the Wright machine r.p.m. = 450; in Blériot XI. r.p.m. = 1350.
[33] Such propellers, however, require a considerable amount of
rubber.
[34] But _see also_ § 22.
[35] "Flight," March 10, 1910. (Illustration reproduced by
permission.)
[36] According to the author's views on the subject.
CHAPTER VI.
THE QUESTION OF SUSTENTATION THE CENTRE OF PRESSURE.
§ 1. Passing on now to the study of an aeroplane actually in the air,
there are two forces acting on it, the upward lift due to the air
(i.e. to the movement of the aeroplane supposed to be continually
advancing on to fresh, undisturbed _virgin_ air), and the force due to
the weight acting vertically downwards. We can consider the resultant
of all the upward sustaining forces as acting at a single point--that
point is called the "Centre of Pressure."
Suppose A B a vertical section of a flat aerofoil, inclined at a small
angle _a_ to the horizon C, the point of application of the resultant
upward 'lift,' D the point through which the weight acts vertically
downwards. Omitting for the moment the action of propulsion, if these
two forces balance there will be equilibrium; but to do this they must
pass through the same point, but as the angle of inclination varies,
so does the centre of pressure, and some means must be employed
whereby if C and D coincide at a certain angle the aeroplane will come
back to the correct angle of balance if the latter be altered.
In a model the means must be automatic. Automatic stability depends
for its action upon the movement of the centre of pressure when the
angle of incidence varies. When the angle of incidence increases the
centre of pressure moves backwards towards the rear of the aerofoil,
and vice versa.
Let us take the case when steady flight is in progress and C and D are
coincident, suppose the velocity of the wind suddenly to
increase--increased lifting effect is at once the result, and the fore
part of the machine rises, i.e. the angle of incidence increases and
the centre of pressure moves back to some point in the rear of C D.
The weight is now clearly trying to pull the nose of the aeroplane
down, and the "lift" tending to raise the tail. The result being an
alteration of the angle of incidence, or angle of attack as it is
called, until it resumes its original position of equilibrium. A drop
in the wind causes exactly an opposite effect.
[Illustration: FIG. 42.]
§ 2. The danger lies in "oscillations" being set up in the line of
flight due to changes in the position of the centre of pressure. Hence
the device of an elevator or horizontal tail for the purpose of
damping out such oscillations.
§ 3. But the aerofoil surface is not flat, owing to the increased
"lift" given by arched surfaces, and a much more complicated set of
phenomena then takes place, the centre of pressure moving forward
until a certain critical angle of incidence is reached, and after
this a reversal takes place, the centre of pressure then actually
moving backwards.
The problem then consists in ascertaining the most efficient aerocurve
to give the greatest "lift" with the least "drift," and, having found
it, to investigate again experimentally the movements of the centre of
pressure at varying angles, and especially to determine at what angle
(about) this "reversal" takes place.
[Illustration: FIG. 43.]
§ 4. Natural automatic stability (the only one possible so far as
models are concerned) necessitates permanent or a permanently
recurring coincidence (to coin a phrase) of the centre of gravity and
the centre of pressure: the former is, of course, totally unaffected
by the vagaries of the latter, any shifting of which produces a couple
tending to destroy equilibrium.
§ 5. As to the best form of camber (for full sized machine) possibly
more is known on this point than on any other in the whole of
aeronautics.
In Figs. 44 and 45 are given two very efficient forms of cambered
surfaces for models.
[Illustration: FIG. 44.--AN EFFICIENT FORM OF CAMBER.
B D Maximum Altitude. A C Chord.
Ratio of B D: A C :: 1:17. A D 1/3 of A C.]
[Illustration: FIG. 45.--ANOTHER EFFICIENT FORM.
Ratio of B D to A C 1 to 17. AD rather more than ¼ of A C.]
The next question, after having decided the question of aerocurve, or
curvature of the planes, is at what angle to set the cambered surface
to the line of flight. This brings us to the question of the--
§ 6. =Dipping Front Edge.=--The leading or front edge is not
tangential to the line of flight, but to a relative upward wind. It is
what is known as the "cyclic up-current," which exists in the
neighbourhood of the entering edge. Now, as we have stated before, it
is of paramount importance that the aerofoil should receive the air
with as little shock as possible, and since this up-current does
really exist to do this, it must travel through the air with a dipping
front edge. The "relative wind" (the only one with which we are
concerned) _is_ thereby met tangentially, and as it moves onward
through the air the cambered surface (or aerocurve) gradually
transforms this upward trend into a downward wake, and since by
Newton's law, "Action and reaction are equal and opposite," we have
an equal and opposite upward reaction.
We now know that the top (or convex side) of the cambered surface is
practically almost as important as the underneath or concave side in
bringing this result about.
The exact amount of "dipping edge," and the exact angle at which the
chord of the aerocurve, or cambered surface, should be set to the line
of flight--whether at a positive angle, at no angle, or at a negative
angle--is one best determined by experiment on the model in question.
[Illustration: FIG. 46.]
But _if at any angle, that angle either way should be a very small
one_. If you wish to be very scientific you can give the underside of
the front edge a negative angle of 5° to 7° for about one-eighth of
the total length of the section, after that a positive angle,
gradually increasing until you finally finish up at the trailing edge
with one of 4°. Also, the form of cambered surface should be a
paraboloid--not arc or arc of circles. The writer does not recommend
such an angle, but prefers an attitude similar to that adopted in the
Wright machine, as in Fig. 47.
§ 7. Apart from the attitude of the aerocurve: _the greatest depth of
the camber should be at one-third of the length of the section from
the front edge, and the total depth measured from the top surface to
the chord at this point should not be more than one-seventeenth of the
length of section_.
§ 8. It is the greatest mistake in model aeroplanes to make the camber
otherwise than very slight (in the case of surfaced aerofoils the
resistance is much increased), and aerofoils with anything but a _very
slight_ arch are liable to be very unstable, for the aerocurve has
always a decided tendency to "follow its own curve."
[Illustration: FIG. 47.--ATTITUDE OF WRIGHT MACHINE.]
The nature of the aerocurve, its area, the angle of inclination of its
chord to the line of flight, its altitude, etc., are not the only
important matters one must consider in the case of the aerofoil, we
must also consider--
§ 9. Its =Aspect Ratio=, i.e. the ratio of the span (length) of the
aerofoil to the chord--usually expressed by span/chord. In the Farman
machine this ratio is 5·4; Blériot, 4·3; Short, 6 to 7·5; Roe
triplane, 7·5; a Clark flyer, 9·6.
Now the higher the aspect ratio the greater should be the efficiency.
Air escaping by the sides represents loss, and the length of the sides
should be kept short. A broader aerofoil means a steeper angle of
inclination, less stability, unnecessary waste of power, and is
totally unsuited for a model--to say nothing of a full-sized machine.
In models this aspect ratio may with advantage be given a higher value
than in full-sized machines, where it is well known a practical safe
constructional limit is reached long before theory suggests the
limit. The difficulty consists in constructing models having a very
high aspect ratio, and yet possessing sufficient strength and
lightness for successful flight. It is in such a case as this where
the skill and ingenuity of the designer and builder come in.
It is this very question of aspect ratio which has given us the
monoplane, the biplane, and the triplane. A biplane has a higher
aspect ratio than a monoplane, and a triplane (see above) a higher
ratio still.
It will be noticed the Clark model given has a considerably higher
aspect ratio, viz. 9·6. And even this can be exceeded.
_An aspect ratio of_ 10:1 _or even_ 12:1 _should be used if
possible._[37]
§ 10. =Constant or Varying Camber.=--Some model makers vary the camber
of their aerofoils, making them almost flat in some parts, with
considerable camber in others; the tendency in some cases being to
flatten the central portions of the aerofoil, and with increasing
camber towards the tips. In others the opposite is done. The writer
has made a number of experiments on this subject, but cannot say he
has arrived at any very decisive results, save that the camber should
in all cases be (as stated before) very slight, and so far as his
experiments do show anything, they incline towards the further
flattening of the camber in the end portions of the aerofoil. It must
not be forgotten that a flat-surfaced aerofoil, constructed as it is
of more or less elastic materials, assumes a natural camber, more or
less, when driven horizontally through the air. Reference has been
made to a reversal of the--
§ 11. =Centre of Pressure on Arched Surfaces.=--Wilbur Wright in his
explanation of this reversal says: "This phenomenon is due to the fact
that at small angles the wind strikes the forward part of the aerofoil
surface on the upper side instead of the lower, and thus this part
altogether ceases to lift, instead of being the most effective part of
all." The whole question hangs on the value of the critical angle at
which this reversal takes place; some experiments made by Mr. M.B.
Sellers in 1906 (published in "Flight," May 14, 1910) place this angle
between 16° and 20°. This angle is much above that used in model
aeroplanes, as well as in actual full-sized machines. But the
equilibrium of the model might be upset, not by a change of attitude
on its part, but on that of the wind, or both combined. By giving (as
already advised) the aerofoil a high aspect ratio we limit the travel
of the centre of pressure, for a high aspect ratio means, as we have
seen, a short chord; and this is an additional reason for making the
aspect ratio as high as practically possible. The question is, is the
critical angle really as high as Mr. Seller's experiments would show.
Further experiments are much needed.
FOOTNOTES:
[37] Nevertheless some models with a very low aspect ratio make good
flyers, owing to their extreme lightness.
CHAPTER VII.
MATERIALS FOR AEROPLANE CONSTRUCTION.
§ 1. The choice of materials for model aeroplane construction is more
or less limited, if the best results are to be obtained. The lightness
absolutely essential to success necessitates--in addition to skilful
building and best disposition of the materials--materials of no undue
weight relative to their strength, of great elasticity, and especially
of great resilience (capacity to absorb shock without injury).
§ 2. =Bamboo.=--Bamboo has per pound weight a greater resilience than
any other suitable substance (silk and rubber are obviously useless as
parts of the _framework_ of an aeroplane). On full-sized machines the
difficulty of making sufficiently strong connections and a liability
to split, in the larger sizes, are sufficient reasons for its not
being made more use of; but it makes an almost ideal material for
model construction. The best part to use (split out from the
centrepiece) is the strip of tough wood immediately below the hard
glazed surface. For struts, spars, and ribs it can be used in this
manner, and for the long strut supporting the rubber motor an entire
tube piece should be used of the requisite strength required; for an
ordinary rubber motor (one yard long), 30 to 50 strands, this should
be a piece 3/8 in. in diameter, and weight about 5/8 oz. per ft.
_Bamboo may be bent_ by either the "dry" heat from a spirit lamp or
stove, or it may be steamed, the latter for preference, as there is
no danger of "scorching" the fibres on the inside of the bend. When
bent (as in the case of other woods) it should be bound on to a
"former" having a somewhat greater curvature than the curve required,
because when cool and dry it will be sure to "go back" slightly. It
must be left on the former till quite dry. When bending the "tube"
entire, and not split portions thereof, it should be immersed in very
hot, or even boiling, water for some time before steaming. The really
successful bending of the tube _en bloc_ requires considerable
patience and care.
Bamboo is inclined to split at the ends, and some care is required in
making "joints." The ribs can be attached to the spars by lashing them
to thin T strips of light metal, such as aluminium. Thin thread, or
silk, is preferable to very thin wire for lashing purpose, as the
latter "gives" too much, and cuts into the fibres of the wood as well.
§ 3. =Ash=, =Spruce=, =Whitewood= are woods that are also much used by
model makers. Many prefer the last named owing to its uniform freedom
from knots and ease with which it can be worked. It is stated 15 per
cent. additional strength can be imparted by using hot size and
allowing it to soak into the wood at an increase only of 3·7 per cent.
of weight. It is less than half the weight of bamboo, but has a
transverse rupture of only 7,900 lb. per sq. in. compared to 22,500 in
the case of bamboo tubing (thickness one-eighth diameter) and a
resilience per lb. weight of slightly more than one half. Some model
makers advocate the use of =poplar= owing to its extreme lightness
(about the same as whitewood), but its strength is less in the ratio
of about 4:3; its resilience is very slightly more. It must be
remembered that wood of the same kind can differ much as to its
strength, etc., owing to what part of the tree it may have been cut
from, the manner in which it may have been seasoned, etc. For model
aeroplanes all wood used should have been at least a year in
seasoning, and should be so treated when in the structure that it
cannot absorb moisture.
If we take the resilience of ash as 1, then (according to Haswell)
relative resilience of beech is 0·86, and spruce 0·64.
The strongest of woods has a weight when well seasoned of about 40 lb.
per cub. ft. and a tenacity of about 10,000 lb. per sq. in.
[Illustration: FIG. 47A.--"AEROPLANE ALMA."
A very effective French Toy Monoplane.]
§ 4. =Steel.=--Ash has a transverse rupture of 14,300 lb. per sq. in.,
steel tubing (thickness = 1/30 its diameter) 100,000 lb. per sq. in.
Ash weighs per cub. ft. 47 lb., steel 490. Steel being more than ten
times as heavy as ash--but a transverse rupture stress seven times as
high.
Bamboo in tube form, thickness one-third of diameter, has a
transverse rupture of 22,500 lb. per sq. in., and a weight of 55 lb.
per cub. ft.
Steel then is nine times as heavy as bamboo--and has a transverse
rupture stress 4·4 times as great. In comparing these three substances
it must be carefully borne in mind that lightness and strength are not
the only things that have to be provided for in model aeroplane
building; there is the question of _resistance_--we must offer as
small a cross-section to moving through the air as possible.
Now while ash or bamboo and certain other timbers may carry a higher
load per unit of weight than steel, they will present about three to
three and a half times the cross-section, and this produces a serious
obstacle, while otherwise meeting certain requirements that are most
desirable. Steel tubing of sufficiently small bore is not, so far as
the writer knows, yet on the market in England. In France very thin
steel tubes are made of round, oval, hexagon, etc., shape, and of
accurate thickness throughout, the price being about 18s. a lb.
Although suitable steel tubing is not yet procurable under ordinary
circumstances, umbrella steel is.
§ 5. =Umbrella Section Steel= is a section 5/32 in. by 1/8 in. deep, 6
ft. long weighing 2·1 oz., and a section 3/32 in. across the base by
1/8 in. deep, 6 ft. long weighing 1·95 oz.
It is often stated that umbrella ribs are too heavy--but this entirely
depends on the length you make use of, in lengths of 25 in. for small
aerofoils made from such lengths it is so; but in lengths of 48 in.
(two such lengths joined together) the writer has used it with great
success; often making use of it now in his larger models; the
particular size used by him weighs 13½ grammes, to a length of 25
in. He has never had one of these aerofoils break or become
kinked--thin piano wire is used to stay them and also for spars when
employed--the front and ends of the aerofoil are of umbrella steel,
the trailing edge of steel wire, comparatively thin, kept taut by
steel wire stays.
§ 6. =Steel Wire.=--Tensile strength about 300,000 lb. per sq. in. For
the aerofoil framework of small models and for all purposes of
staying, or where a very strong and light tension is required, this
substance is invaluable. Also for framework of light fabric covered
propellers as well as for skids and shock absorber--also for hooks to
hold the rubber motor strands, etc. No model is complete without it in
some form or another.
§ 7. =Silk.=--This again is a _sine qua non_. Silk is the strongest of
all organic substances for certain parts of aeroplane construction. It
has, in its best form, a specific gravity of 1·3, and is three times
as strong as linen, and twice as strong in the thread as hemp. Its
finest fibres have a section of from 0·0010 to 0·0015 in diameter. It
will sustain about 35,000 lb. per sq. in. of its cross section; and
its suspended fibre should carry about 150,000 ft. of its own
material. This is six times the same figure for aluminium, and equals
about 75,000 lb. steel tenacity, and 50 more than is obtained with
steel in the form of watch springs or wire. For aerofoil surface no
substance can compare with it. But it must be used in the form of an
"oiled" or specially treated silk. Several such are on the market.
Hart's "fabric" and "radium" silk are perhaps the best known. Silk
weighs 62 lb. per cub. ft., steel has, we have seen, 490 lb., thus
paying due regard to this and to its very high tensile strength it is
superior to even steel wire stays.
§ 8. =Aluminium and Magnalium.=--Two substances about which a great
deal has been heard in connection with model aeroplaning; but the
writer does not recommend their use save in the case of fittings for
scale models, not actual flyers, unless especially light ones meant
to fly with the wind. Neither can compare with steel. Steel, it is
true, is three times as heavy as aluminium, but it has four or five
times its strength; and whereas aluminium and magnalium may with
safety be given a permissible breaking strength of 60 per cent. and 80
per cent. respectively, steel can easily be given 80 per cent. Being
also less in section, resistance to air travel is again less as in the
case of wood. In fact, steel scores all round. Weight of magnalium :
weight of aluminium :: 8:9.
§ 9. =Alloys.=--During recent years scores, hundreds, possibly
thousands of different alloys have been tried and experimented on, but
steel still easily holds its own. It is no use a substance being
lighter than another volume for volume, it must be _lighter and
stronger weight for weight_, to be superior for aeronautical purpose,
and if the difference be but slight, question of _bulk_ may decide it
as offering _less resistance_.
§ 10. =Sheet Ebonite.=--This substance is sometimes useful for
experiments with small propellers, for it can be bent and moulded in
hot water, and when cold sets and keeps its shape. _Vulcanized fibre_
can be used for same purpose. _Sheet celluloid_ can be used in the
same way, but in time it becomes brittle and shrinks. _Mica_ should be
avoided. _Jointless cane_ in various sizes is a very useful
material--the main aerofoil can be built of it, and it is useful for
skids, and might be made more use of than it is.[38] _Three ply wood_,
from 1/50 in. in thickness, is now on the market. Four or five ply
wood can also be obtained. To those desiring to build models having
wooden aerofoils such woods offer the advantage of great strength and
extreme lightness.
Referring to Table V. (Timber) at the end of the book, apparently the
most suitable wood is Lombardy poplar; but its light weight means
increased bulk, i.e. additional air resistance. Honduras mahogany is
really a better all-round wood, and beech is not far behind.
Resilience is an important factor. Ash heads the list; but mahogany's
factor is also good, and in other respects superior.
Lombardy poplar ought to be a very good wood for propellers, owing to
its lightness and the ease with which it can be worked.
_Hollow reeds_, and even _porcupine quills_, have been pressed into
the service of the model maker, and owing to their great strength and
extreme lightness, more especially the latter, are not without their
uses.
FOOTNOTES:
[38] The chief advantage of cane--its want of stiffness, or facility
in bending--is for some parts of the machine its chief disadvantage,
where stiffness with resilience is most required.
CHAPTER VIII.
HINTS ON THE BUILDING OF MODEL AEROPLANES.
§ 1. The chief difficulty in the designing and building of model
aeroplanes is to successfully combat the conflicting interests
contained therein. Weight gives stability, but requires extra
supporting surface or a higher speed, i.e. more power, i.e. more
weight. Inefficiency in one part has a terrible manner of repeating
itself; for instance, suppose the aerofoil surface inefficient--badly
designed--this means more resistance; more resistance means more
power, i.e. weight, i.e. more surface, and so on _ad infinitum_.
It is because of circumstances like the above that it is so difficult
to _design_ really good and efficient flying models; the actual
building of them is not so difficult, but few tools are required, none
that are expensive or difficult to use.
In the making of any particular model there are special points that
require special attention; but there are certain general rules and
features which if not adhered to and carefully carried out, or as
carefully avoided, will cause endless trouble and failure.
§ 2. In constructing a model aeroplane, or, indeed, any piece of
aerial apparatus, it is very important not to interrupt the continuity
of any rib, tube, spar, etc., by drilling holes or making too thinned
down holding places; if such be done, additional strength by binding
(with thread, not wire), or by slipping a small piece of slightly
larger tube over the other, must be imparted to the apparatus.
§ 3. Begin by making a simple monoplane, and afterwards as you gain
skill and experience proceed to construct more elaborate and
scientific models.
§ 4. Learn to solder--if you do not know how to--it is absolutely
essential.
§ 5. Do not construct models (intended for actual flight) with a
tractor screw-main plane in front and tail (behind). Avoid them as you
would the plague. Allusion has already been made in the Introduction
to the difficulty of getting the centre of gravity sufficiently
forward in the case of Blériot models; again with the main aerofoil in
front, it is this aerofoil and not the balancing elevator, or tail,
that _first_ encounters the upsetting gust, and the effect of such a
gust acting first on the larger surface is often more than the
balancer can rectify in time to avert disaster. The proper place for
the propeller is behind, in the wake of the machine. If the screw be
in front the backwash from it strikes the machine and has a decidedly
retarding action. It is often contended that it drives the air at an
increased velocity under (and over) the main aerofoil, and so gives a
greater lifting effect. But for proper lifting effect which it can
turn without effort into air columns of proper stream line form what
the aerofoil requires is undisturbed air--not propeller backwash.
The rear of the model is the proper place for the propeller, in the
centre of greatest air disturbance; in such a position it will recover
a portion of the energy lost in imparting a forward movement to the
air, caused by the resistance, the model generally running in such
air--the slip of the screw is reduced to a corresponding degree--may
even vanish altogether, and what is known as negative slip occur.
§ 6. Wooden or metal aerofoils are more efficient than fabric covered
ones. But they are only satisfactory in the smaller sizes, owing, for
one thing, to the smash with which they come to the ground. This being
due to the high speed necessary to sustain their weight. For
larger-sized models fabric covered aerofoils should be used.
§ 7. As to the shape of such, only three need be considered--the (_a_)
rectangular, (_b_) the elongated ellipse, (_c_) the chamfered rear
edge.
[Illustration: FIG. 48.--(_a_), (_b_), (_c_).]
§ 8. The stretching of the fabric on the aerofoil framework requires
considerable care, especially when using silk. It is quite possible,
even in models of 3 ft. to 4 ft. spread, to do without "ribs," and
still obtain a fairly correct aerocurve, if the material be stretched
on in a certain way. It consists in getting a correct longitudinal and
transverse tension. We will illustrate it by a simple case. Take a
piece of thickish steel pianoforte wire, say, 18 in. long, bend it
round into a circle, allowing ½ in. to 1 in. to overlap, tin and
solder, bind this with soft very thin iron wire, and again solder
(always use as little solder as possible). Now stitch on to this a
piece of nainsook or silk, deforming the circle as you do so until it
has the accompanying elliptical shape. The result is one of double
curvature; the transverse curve (dihedral angle) can be regulated by
cross threads or wires going from A to B and C to D.
[Illustration: FIG. 49.]
[Illustration: FIG. 49A.--MR. T.W.K. CLARKE'S 1 OZ. MODEL.]
The longitudinal curve on the camber can be regulated by the original
tension given to it, and by the manner of its fixing to the main
framework. Suitable wire projections or loops should be bound to it by
wire, and these fastened to the main framework by binding with _thin_
rubber cord, a very useful method of fastening, since it acts as an
excellent shock absorber, and "gives" when required, and yet
possesses quite sufficient practical rigidity.
§ 9. Flexible joints are an advantage in a biplane; these can be made
by fixing wire hooks and eyes to the ends of the "struts," and holding
them in position by binding with silk or thread. Rigidity is obtained
by use of steel wire stays or thin silk cord.
[Illustration: FIG. 49B.--MR. T.W.K. CLARKE'S 1 OZ. MODEL.
Showing the position of C. of G., or point of support.]
§ 10. Owing to the extra weight and difficulties of construction on so
small a scale it is not desirable to use "double surface" aerofoils
except on large size power-driven models.
§ 11. It is a good plan not to have the rod or tube carrying the
rubber motor connected with the outrigger carrying the elevator,
because the torque of the rubber tends to twist the carrying
framework, and interferes with the proper and correct action of the
elevator. If it be so connected the rod must be stayed with piano
wire, both longitudinally (to overcome the pull which we know is very
great), and also laterally, to overcome the torque.
[Illustration: FIG. 49C.--A LARGE MODEL AEROPLANE.
Shown without rubber or propellers. Designed and constructed by the
writer. As a test it was fitted with two 14 in. propellers revolving
in the _same_ direction, and made some excellent flights under these
conditions, rolling slightly across the wind, but otherwise keeping
quite steady. Total weight, 1½ lb.; length, 6 ft.; span of main
aerofoil, 5 ft. Constructed of bamboo, cane, and steel wire. Front
skids steel wire. Back skids cane. Aerofoil covering nainsook.]
§ 12. Some builders place the rubber motor above the rod, or bow frame
carrying the aerofoils, etc., the idea being that the pull of the
rubber distorts the frame in such a manner as to "lift" the elevator,
and so cause the machine to rise rapidly in the air. This it does; but
the model naturally drops badly at the finish and spoils the effect.
It is not a principle that should be copied.
[Illustration: FIG. 49D.--A VERY LIGHT WEIGHT MODEL.
Constructed by the author. Provided with twin propellers of a modified
Fleming-Williams type. This machine flew well when provided with an
abnormal amount of rubber, owing to the poor dynamic thrust given by
the propellers.]
§ 13. In the Clarke models with the small front plane, the centre of
pressure is slightly in front of the main plane.
The balancing point of most models is generally slightly in front, or
just within the front edge of the main aerofoil. The best plan is to
adjust the rod carrying the rubber motor and propeller until the best
balance is obtained, then hang up the machine to ascertain the centre
of gravity, and you will have (approximately) the centre of pressure.
[Illustration: FIG. 49E.--USEFUL FITTINGS FOR MODELS.
1. Rubber tyred wheels. 2. Ball-bearing steel axle shafts. 3. Brass wire
strainers with steel screws; breaking strain 200 lb. 4. Magnalium
tubing. 5. Steel eyebolt. 6. Aluminium "T" joint. 7. Aluminium "L"
piece. 8. Brass brazed fittings. 9. Ball-bearing thrust. 10. Flat
aluminium "L" piece. (_The above illustrations taken (by permission)
from Messrs. Gamage's catalogue on Model Aviation._)]
§ 14. The elevator (or tail) should be of the non-lifting type--in
other words, the entire weight should be carried by the main aerofoil
or aerofoils; the elevator being used simply as a balancer.[39] If the
machine be so constructed that part of the weight be carried by the
elevator, then either it must be large (in proportion) or set up at a
large angle to carry it. Both mean considerably more resistance--which
is to be avoided. In practice this means the propeller being some
little distance in rear of the main supporting surface.
[Illustration: FIG. 49F.--USEFUL FITTINGS FOR MODELS.
11. Aluminium ball thrust and racket. 12. Ball-bearing propeller,
thrust, and stay.
(_The above illustrations taken (by permission) from Messrs. Gamage's
catalogue on Model Aviation._)]
§ 15. In actual flying models "skids" should be used and not "wheels";
the latter to be of any real use must be of large diameter, and the
weight is prohibitive. Skids can be constructed of cane, imitation
whalebone, steel watch or clock-spring, steel pianoforte wire. Steel
mainsprings are better than imitation whalebone, but steel pianoforte
wire best of all. For larger sized models bamboo is also suitable, as
also ash or strong cane.
§ 16. Apart from or in conjunction with skids we have what are termed
"shock absorbers" to lessen the shock on landing--the same substances
can be used--steel wire in the form of a loop is very effectual;
whalebone and steel springs have a knack of snapping. These shock
absorbers should be so attached as to "give all ways" for a part side
and part front landing as well as a direct front landing. For this
purpose they should be lashed to the main frame by thin indiarubber
cord.
§ 17. In the case of a biplane model the "gap" must not be less than
the "chord"--preferably greater.
In a double monoplane (of the Langley type) there is considerable
"interference," i.e. the rear plane is moving in air already acted on
by the front one, and therefore moving in a downward direction. This
means decreased efficiency. It can be overcome, more or less, by
varying the dihedral angle at which the two planes are set; but cannot
be got rid of altogether, or by placing them far apart. In biplanes
not possessing a dihedral angle--the propeller can be placed
_slightly_ to one side--in order to neutralise the torque of the
propeller--the best portion should be found by experiment--unless the
pitch be very large; with a well designed propeller this is not by any
means essential. If the propeller revolve clockwise, place it towards
the right hand of the machine, and vice versa.
§ 18. In designing a model to fly the longest possible distance the
monoplane type should be chosen, and when desiring to build one that
shall remain the longest time in the air the biplane or triplane type
should be adopted.[40] For the longest possible flight twin propellers
revolving in opposite directions[41] are essential. To take a concrete
case--one of the writer's models weighed complete with a single
propeller 8½ oz. It was then altered and fitted with two propellers
(same diameter and weight); this complete with double rubber weighed
10¼ oz. The advantage double the power. Weight increased only 20
per cent., resistance about 10 per cent., total 30 per cent. Gain 70
per cent. Or if the method of gearing advocated (see Geared Motors) be
adopted then we shall have four bunches of rubber instead of two, and
can thereby obtain so many more turns.[42] The length of the strands
should be such as to render possible at least a thousand turns.
The propellers should be of large diameter and pitch (not less than
35° at the tips), of curved shape, as advocated in § 22 ch. v.; the
aerofoil surface of as high an aspect ratio as possible, and but
slight camber if any; this is a very difficult question, the question
of camber, and the writer feels bound to admit he has obtained as long
flights with surfaces practically flat, but which do, of course,
camber slightly in a suitable wind, as with stiffer cambered surfaces.
Wind cambered surfaces are, however, totally unsuitable in gusty
weather, when the wind has frequently a downward trend, which has the
effect of cambering the surface the wrong way about, and placing the
machine flat on the ground. Oiled or specially prepared silk of the
lightest kind should be used for surfacing the aerofoils. Some form of
keel, or fin, is essential to assist in keeping the machine in a
straight course, combined with a rudder and universally jointed
elevator.
The manner of winding up the propellers has already been referred to
(_see_ chap. iii., § 9). A winder is essential.
Another form of aerofoil is one of wood (as in Clarke's flyers) or
metal, such a machine relying more on the swiftness of its flight than
on its duration. In this the gearing would possibly not be so
advantageous--but experiment alone could decide.
The weight of the machine would require to be an absolute minimum, and
everything not absolutely essential omitted.
It is quite possible to build a twin-screw model on one central stick
alone; but the isosceles triangular form of framework, with two
propellers at the base corners, and the rubber motors running along
the two sides and terminating at the vertex, is preferred by most
model makers. It entails, of course, extra weight. A light form of
skid, made of steel pianoforte wire, should be used. As to the weight
and size of the model, the now famous "one-ouncers" have made some
long flights of over 300 yards[43]; but the machine claiming the
record, half a mile,[44] weighs about 10 oz. And apart from this
latter consideration altogether the writer is inclined to think that
from 5 oz. to 10 oz. is likely to prove the most suitable. It is not
too large to experiment with without difficulty, nor is it so small as
to require the skill of a jeweller almost to build the necessary
mechanism. The propeller speed has already been discussed (_see_ ch.
v., § 15). The model will, of course, be flown with the wind. The
_total_ length of the model should be at least twice the span of the
main aerofoil.
FOOTNOTES:
[39] This is a good plan--not a rule. Good flying models can, of
course, be made in which this does not hold.
[40] This is in theory only: in practice the monoplane holds both
records.
[41] The best position for the propellers appears to be one in front
and one behind, when extreme lightness is the chief thing desired.
[42] Because the number of strands of rubber in each bunch will be
much less.
[43] Mr. Burge Webb claims a record of 500 yards for one of his.
[44] Flying, of course, with the wind. _Note._--In the "Model
Engineer" of July 7, 1910, will be found an interesting account (with
illustrations) of Mr. W.G. Aston's 1 oz. model, which has remained in
the air for over a minute.
CHAPTER IX.
THE STEERING OF THE MODEL.
§ 1. Of all the various sections of model aeroplaning that which is
the least satisfactory is the above.
The torque of the propeller naturally exerts a twisting or tilting
effect upon the model as a whole, the effect of which is to cause it
to fly in (roughly speaking) a circular course, the direction
depending on whether the pitch of the screw be a right or left handed
one. There are various devices by which the torque may be
(approximately) got rid of.
§ 2. In the case of a monoplane, by not placing the rod carrying the
rubber motor in the exact centre of the main aerofoil, but slightly to
one side, the exact position to be determined by experiment.
In a biplane the same result is obtained by keeping the rod in the
centre, but placing the bracket carrying the bearing in which the
propeller shaft runs at right angles horizontally to the rod to obtain
the same effect.
§ 3. The most obvious solution of the problem is to use _two_ equal
propellers (as in the Wright biplane) of equal and opposite pitch,
driven by two rubber motors of equal strength.
Theoretically this idea is perfect. In practice it is not so. It is
quite possible, of course, to use two rubber motors of an equal number
of strands (equality should be first tested by _weighing_). It should
be possible to obtain two propellers of equal and opposite pitch,
etc., and it is also possible to give the rubber motors the same
number of turns. In practice one is always wound up before the other.
This is the first mistake. They should be wound up _at the same time_,
using a double winder made for the purpose.
The fact that this is _not_ done is quite sufficient to give an
unequal torsion. The friction in both cases must also be exactly
equal. Both propellers must be released at exactly the same instant.
Supposing _all_ these conditions fulfilled (in practice they never
are), supposing also the propellers connected by gearing (prohibitive
on account of the weight), and the air quite calm (which it never is),
then the machine should and undoubtedly would _fly straight_.
For steering purposes by winding up one propeller _many more times_
than the other, the aeroplane can generally speaking be steered to the
right or left; but from what I have both seen and tried twin-screw
model aeroplanes are _not_ the success they are often made out to be,
and they are much more troublesome to deal with, in spite of what some
say to the contrary.
The solution of the problem of steering by the use of two propellers
is only partially satisfactory and reliable, in fact, it is no
solution at all.[45] The torque of the propeller and consequent
tilting of the aeroplane is not the only cause at work diverting the
machine from its course.
§ 4. As it progresses through the air it is constantly meeting air
currents of varying velocity and direction, all tending to make the
model deviate more or less from its course; the best way, in fact, the
only way, to successfully overcome such is by means of _speed_, by
giving the aeroplane a high velocity, not of ten or twelve to fifteen
miles an hour, as is usual in built up fabric-covered aerofoils, but a
velocity of twenty to thirty miles an hour, attainable only in models
(petrol or steam driven) or by means of wooden or metal aerofoils.
§ 5. Amongst devices used for horizontal steering are vertical "FINS."
These should be placed in the rear above the centre of gravity. They
should not be large, and can be made of fabric tightly stretched over
a wire frame, or of a piece of sheet magnalium or aluminium, turning
on a pivot at the front edge, adjustment being made by simply twisting
the fin round to the desired angle. As to the size, think of rudder
and the size of a boat, but allow for the difference of medium. The
frame carrying the pivot and fin should be made to slide along the rod
or backbone of the model in order to find the most efficient position.
§ 6. Steering may also be attempted by means of little balancing tips,
or ailerons, fixed to or near the main aerofoil, and pivoted (either
centrally or otherwise) in such a manner that they can be rotated one
in one direction (tilted) and the other in the other (dipped), so as
to raise one side and depress the other.
§ 7. The model can also be steered by giving it a cant to one side by
weighting the tip of the aerofoil on that side on which it is desired
it should turn, but this method is both clumsy and "weighty."
§ 8. Another way is by means of the elevator; and this method, since
it entails no additional surfaces entailing extra resistance and
weight, is perhaps the most satisfactory of all.
It is necessary that the elevator be mounted on some kind of universal
joint, in order that it may not only be "tipped" or "dipped," but also
canted sideways for horizontal steering.
§ 9. A vertical fin in the rear, or something in the nature of a
"keel," i.e. a vertical fin running down the backbone of the machine,
greatly assists this movement.
If the model be of the tractor screw and tail (Blériot) type, then the
above remarks _re_ elevator apply _mutatis mutandis_ to the tail.
§ 10. It is of the most vital importance that the propeller torque
should be, as far as possible, correctly balanced. This can be tested
by balancing the model transversely on a knife edge, winding up the
propeller, and allowing it to run down, and adjusting matters until
the torque and compensatory apparatus balance. As the torque varies
the mean should be used.
In the case of twin propellers, suspend the model by its centre of
gravity, wind up the propellers, and when running down if the model is
drawn forward without rotation the thrust is equal; if not adjustment
must be made till it does. The easiest way to do this _may_ be by
placing one propeller, the one giving the greater thrust, slightly
nearer the centre.
In the case of two propellers rotating in opposite directions (by
suitable gearing) on the common centre of two axes, one of the axes
being, of course, hollow, and turning on the other--the rear propeller
working in air already driven back by the other will require a coarser
pitch or larger diameter to be equally efficient.
FOOTNOTE:
[45] These remarks apply to rubber driven motors. In the case of
two-power driven propellers in which the power was automatically
adjusted, say, by a gyroscope as in the case of a torpedo--and the
_speed_ of each propeller varied accordingly--the machine could, of
course, be easily steered by such means; but the model to carry such
power and appliances would certainly weigh from 40 lb. to 60 lb.
CHAPTER X.
THE LAUNCHING OF THE MODEL.
§ 1. Generally speaking, the model should be launched into the air
_against the wind_.
§ 2. It should (theoretically) be launched into the air with a
velocity equal to that with which it flies. If it launch with a
velocity in excess of that it becomes at once unstable and has to
"settle down" before assuming its normal line of flight. If the
velocity be insufficient, it may be unable to "pick up" its requisite
velocity in time to prevent its falling to the ground. Models with
wooden aerofoils and a high aspect ratio designed for swift flying,
such as the well-known Clarke flyers, require to be practically
"hurled" into the air.
Other fabric-covered models capable of sustentation at a velocity of 8
to 10 miles an hour, may just be "released."
§ 3. Light "featherweight" models designed for long flights when
travelling with the wind should be launched with it. They will not
advance into it--if there be anything of a breeze--but, if well
designed, just "hover," finally sinking to earth on an even keel. Many
ingenious pieces of apparatus have been designed to mechanically
launch the model into the air. Fig. 50 is an illustration of a very
simple but effective one.
§ 4. For large size power-driven models, unless provided with a
chassis and wheels to enable them to run along and rise from the
ground under their own power, the launching is a problem of
considerable difficulty.
§ 5. In the case of rubber-driven models desired to run along and rise
from the ground under their own power, this rising must be
accomplished quickly and in a short space. A model requiring a 50 ft.
run is useless, as the motor would be practically run out by that
time. Ten or twelve feet is the limit; now, in order to rise quickly
the machine must be light and carry considerable surface, or, in other
words, its velocity of sustentation must be a low one.
[Illustration: FIG. 50.--MR. POYNTER'S LAUNCHING APPARATUS.
(_Reproduced by permission from the "Model Engineer."_)]
§ 6. It will not do to tip up the elevator to a large angle to make it
rise quickly, because when once off the ground the angle of the
elevator is wrong for actual flight and the model will probably turn a
somersault and land on its back. I have often seen this happen. If the
elevator be set at an increased angle to get it to rise quickly, then
what is required is a little mechanical device which sets the elevator
at its proper flight angle when it leaves the ground. Such a device
does not present any great mechanical difficulties; and I leave it to
the mechanical ingenuity of my readers to devise a simple little
device which shall maintain the elevator at a comparatively large
angle while the model is on the ground, but allowing of this angle
being reduced when free flight is commenced.
§ 7. The propeller most suitable to "get the machine off the ground"
is one giving considerable statical thrust. A small propeller of fine
pitch quickly starts a machine, but is not, of course, so efficient
when the model is in actual flight. A rubber motor is not at all well
adapted for the purpose just discussed.
§ 8. Professor Kress uses a polished plank (down which the models slip
on cane skids) to launch his models.
§ 9. When launching a twin-screw model the model should be held by
each propeller, or to speak more correctly, the two brackets holding
the bearings in which the propeller shafts run should be held one in
each hand in such a way, of course, as to prevent the propellers from
revolving. Hold the machine vertically downwards, or, if too large for
this, allow the nose to rest slightly on the ground; raise (or swing)
the machine up into the air until a little more than horizontal
position is attained, and boldly push the machine into the air (moving
forward if necessary) and release both brackets and screws
simultaneously.[46]
§ 10. In launching a model some prefer to allow the propellers to
revolve for a few moments (a second, say) _before_ actually launching,
contending that this gives a steadier initial flight. This is
undoubtedly the case, see note on page 111.
§ 11. In any case, unless trying for a height prize, do not point the
nose of the machine right up into the air with the idea that you will
thereby obtain a better flight.
Launch it horizontally, or at a very small angle of inclination. When
requiring a model to run along a field or a lawn and rise therefrom
this is much facilitated by using a little strip of smooth oilcloth on
which it can run. Remember that swift flying wooden and metal models
require a high initial velocity, particularly if of large size and
weight. If thrown steadily and at the proper angle they can scarcely
be overthrown.
FOOTNOTE:
[46] Another and better way--supposing the model constructed with a
central rod, or some suitable holdfast (this should be situated at the
centre of gravity of the machine) by which it can be held in one
hand--is to hold the machine with both hands above the head, the right
hand grasping it ready to launch it, and the left holding the two
propellers. Release the propellers and allow them a brief interval
(about half a second) to start. Then launch boldly into the air. The
writer has easily launched 1½ lb. models by this means, even in a
high wind. Never launch a model by one hand only.
CHAPTER XI.
HELICOPTER MODELS.
§ 1. There is no difficulty whatever about making successful model
helicopters, whatever there may be about full-sized machines.
§ 2. The earliest flying models were helicopters. As early as 1796 Sir
George Cayley constructed a perfectly successful helicopter model (see
ch. iii.); it should be noticed the screws were superimposed and
rotated in opposite directions.
§ 3. In 1842 a Mr. Phillips constructed a successful power-driven
model helicopter. The model was made entirely of metal, and when
complete and charged weighed 2 lb. It consisted of a boiler or steam
generator and four fans supported between eight arms. The fans had an
inclination to the horizon of 20°, and through the arms the steam
rushed on the principle of Hero's engines (Barker's Mill Principle
probably). By the escape of steam from the arms the fans were caused
to revolve with immense energy, so much so that the model rose to an
immense altitude and flew across two fields before it alighted. The
motive power employed was obtained from the combustion of charcoal,
nitre and gypsum, as used in the original fire annihilator; the
products of combustion mixing with water in the boiler and forming
gas-charged steam, which was delivered at high pressure from the
extremities of the eight arms.[47] This model and its flight (fully
authenticated) is full of interest and should not be lost sight of, as
in all probability being the first model actuated by steam which
actually flew.
The helicopter is but a particular phase of the aeroplane.
§ 4. The simplest form of helicopter is that in which the torque of
the propeller is resisted by a vertical loose fabric plane, so
designed as itself to form a propeller, rotating in the opposite
direction. These little toys can be bought at any good toy shop from
about 6_d._ to 1_s._ Supposing we desire to construct a helicopter of
a more ambitious and scientific character, possessing a vertically
rotating propeller or propellers for horizontal propulsion, as well as
horizontally rotating propellers for lifting purposes.
[Illustration: FIG. 51.--INCORRECT WAY OF ARRANGING SCREWS.]
§ 5. There is one essential point that must be carefully attended to,
and that is, _that the horizontal propulsive thrust must be in the
same plane as the vertical lift_, or the only effect will be to cause
our model to turn somersaults. I speak from experience.
When the horizontally revolving propellers are driven in a horizontal
direction their "lifting" powers will be materially increased, as they
will (like an ordinary aeroplane) be advancing on to fresh undisturbed
air.
§ 6. I have not for ordinary purposes advocated very light weight wire
framework fabric-covered screws, but in a case like this where the
thrust from the propeller has to be more than the total weight of the
machine, these might possibly be used with advantage.
§ 7. Instead of using two long vertical rods as well as one long
horizontal one for the rubber strands, we might dispense with the two
vertical ones altogether and use light gearing to turn the torque
action through a right angle for the lifting screws, and use three
separate horizontal rubber strands for the three propellers on a
suitable light horizontal framework. Such should result in a
considerable saving of weight.
[Illustration: FIG. 52.--CORRECT MANNER. A, B, C = Screws.]
§ 8. The model would require something in the nature of a vertical fin
or keel to give the sense of direction. Four propellers, two for
"lift" and two for "drift," would undoubtedly be a better
arrangement.
FOOTNOTE:
[47] Report on First Exhibition of Aeronautical Society of Great
Britain, held at Crystal Palace, June 1868.
CHAPTER XII.
EXPERIMENTAL RECORDS.
A model flying machine being a scientific invention and not a toy,
every devotee to the science should make it his or her business to
keep, as far as they are able, accurate and scientific records. For by
such means as this, and the making known of the same, can a _science_
of model aeroplaning be finally evolved. The following experimental
entry forms, left purposely blank to be filled in by the reader, are
intended as suggestions only, and can, of course, be varied at the
reader's discretion. When you _have_ obtained carefully established
data, do not keep them to yourself, send them along to one of the
aeronautical journals. Do not think them valueless; if carefully
arranged they cannot be that, and may be very valuable.
EXPERIMENTAL DATA.
FORM I.
Column Headings:
A: Model
B: Weight
C: Area of Supporting Surface
D: Aspect Ratio
E: Average Length of Flight in Feet
F: Maximum Flight
G: Time of Flight, A. average
H: M. maximum
I: Kind and Direction of Wind
J: Camber
K: Angle of Inclination of Main Aerofoil to Line of Flight
-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
A | B | C | D | E | F | G | H | I | J | K
-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
| | | | | | A | M | | |
1 | | | | | | | | | |
2 | | | | | | | | | |
3 | | | | | | | | | |
4 | | | | | | | | | |
5 | | | | | | | | | |
6 | | | | | | | | | |
7 | | | | | | | | | |
8 | | | | | | | | | |
9 | | | | | | | | | |
10 | | | | | | | | | |
11 | | | | | | | | | |
12 | | | | | | | | | |
| | | | | | | | | |
-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
FORM I.--_continued_.
Column Headings:
A: Model
B: Weight of (Rubber) Motor
C: Kind of Rubber, Flat, Square or Round
D: Lenght in Inches and Number of Strands
E: Number of Turns
F: Condition at End of Flight
G: Number of Propellers (No.) and Diameter (Diam.)
H: Number of Blades
I: Disc Area (DiscA.) and Pitch (Pitch)
J: Percentage of Slip
K: Thrust
L: Torque in Inche-Ounces
----+----+----+-----+----+----+-----+----+-----+----+----+----+
A | B | C | D | E | F | G | H | I | J | K | L |
----+----+----+-----+----+----+-----+----+-----+----+----+----+
| | | | | | | | | | | | | | |
1 | | | | | | | | | | | | | | |
2 | | | | | | | | | | | | | | |
3 | | | | | | | | | | | | | | |
4 | | | | | | | | | | | | | | |
5 | | | | | | | | | | | | | | |
6 | | | | | | | | | | | | | | |
7 | | | | | | | | | | | | | | |
8 | | | | | | | | | | | | | | |
9 | | | | | | | | | | | | | | |
10 | | | | | | | | | | | | | | |
11 | | | | | | | | | | | | | | |
12 | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | |
----+----+----+-----+----+----+-----+----+-----+----+----+----+
CHAPTER XIII.
MODEL FLYING COMPETITIONS.
§ 1. From time to time flying competitions are arranged for model
aeroplanes. Sometimes these competitions are entirely open, but more
generally they are arranged by local clubs with both closed and open
events.
No two programmes are probably exactly alike, but the following may be
taken as fairly representative:--
1. Longest flight measured in a straight line (sometimes both with and
against the wind).[48]
2. Stability (both longitudinal and transverse).
3. Longest glide when launched from a given height without power, but
with motor and propeller attached.
4. Steering.
5. Greatest height.
6. The best all-round model, including, in addition to the above,
excellence in building.
Generally so many "points" or marks are given for each test, and the
model whose aggregate of points makes the largest total wins the
prize; or more than one prize may be offered--
One for the longest flight.
One for the swiftest flight over a measured distance.
One for the greatest height.
One for stability and steering.
And one for the best all-round model.
The models are divided into classes:--
§ 2. _Aero Models Association's Classification, etc._
A. Models of 1 sq. ft. surface and under.
B. " 2 sq. ft. " "
C. " 4 sq. ft. " "
D. " 8 sq. ft. " "
E. " over 8 sq. ft.
All surfaces, whether vertical, horizontal, or otherwise, to be
calculated together for the above classification.
All round efficiency--marks or points as percentages:--
Distance 40 per cent.
Stability 35 "
Directional control 15 "
Gliding angle 10 "[49]
Two prizes:--
One for length of flight.
One for all-round efficiency (marked as above).
Every competitor to be allowed three trials in each competition, the
best only to count.
All flights to be measured in a straight line from the starting to the
landing point.
Repairs may be made during the competition at the direction of the
judges.[50]
There are one or two other points where flights are _not_ made with
and against the wind. The competitors are usually requested to start
their models from within a given circle of (say) six feet diameter,
and fly them _in any direction_ they please.
"Gliding angle" means that the model is allowed to fall from a height
(say) of 20 ft.
[Illustration: FIG. 53.--MODEL DESIGNED AND CONSTRUCTED BY THE AUTHOR
FOR "GREATEST HEIGHT."
A very lightly built model with a very low aspect ratio, and screw
giving a very powerful dynamic thrust, and carrying rather a large
amount of rubber. Climbs in left-handed spirals.]
"Directional control," that the model is launched in some specified
direction, and must pass as near as possible over some indicated
point.
The models are practically always launched by hand.
§ 3. Those who desire to win prizes at such competitions would do well
to keep the following points well in mind.
1. The distance is always measured in a straight line. It is
absolutely essential that your model should be capable of flying
(approximately) straight. To see, as I have done, model after model
fly quite 150 to 200 yards and finish within 50 yards of the
starting-point (credited flight 50 yards) is useless, and a severe
strain on one's temper and patience.
[Illustration: FIG. 54.--THE GAMAGE CHALLENGE CUP.
Open Competition for longest flight. Crystal Palace, July 27. Won by
Mr. E.W. Twining.]
[Illustration: FIG. 55.--MEDAL WON BY THE AUTHOR IN THE SAME
COMPETITION.]
2. Always enter more than one model, there nearly always is an
entrance fee; never mind the extra shilling or so. Go in to win.
3. It is not necessary that these models should be replicas of one
another. On some days a light fabric-covered model might stand the
best chance; on another day, a swift flying wooden or metal aerofoil.
Against the wind the latter have an immense advantage; also if the day
be a "gusty" one.[51]
4. Always make it a point of arriving early on the ground, so that you
can make some trial flights beforehand. Every ground has its local
peculiarities of air currents, etc.
5. Always be ready in time, or you may be disqualified. If you are
flying a twin-screw model use a special winder, so that both
propellers are wound up at the same time, and take a competent friend
with you as assistant.
6. For all-round efficiency nothing but a good all-round model, which
can be absolutely relied on to make a dozen (approximately) equivalent
flights, is any good.
7. In an open distance competition, unless you have a model which you
can rely on to make a _minimum_ flight of 200 yards, do not enter
unless you know for certain that none of the "crack" flyers will be
present.
8. Do not neglect the smallest detail likely to lead to success; be
prepared with spare parts, extra rubber, one or two handy tools, wire,
thread, etc. Before a lecture, that prince of experimentalists,
Faraday, was always careful to see that the stoppers of all the
bottles were loose, so that there should be no delay or mishap.
9. If the rating of the model be by "weight" (1 oz., 2 oz., 4 oz.,
etc.) and not area, use a model weighing from 10 oz. to a pound.
10. If there is a greatest height prize, a helicopter model should win
it.[52] (The writer has attained an altitude of between three and four
hundred feet with such.) The altitude was arrived at by observation,
not guesswork.
11. It is most important that your model should be able to "land"
without damage, and, as far as possible, on an even keel; do not omit
some form of "skid" or "shock-absorber" with the idea of saving
weight, more especially if your model be a biplane, or the number of
flights may be restricted to the number "one."
12. Since the best "gliding" angle and "flying" angle are not the
same, being, say, 7° in the former case and 1°-3°, say, in the latter,
an adjustable angle might in some cases be advantageous.
13. Never turn up at a competition with a model only just finished and
practically untested which you have flown only on the morning of the
competition, using old rubber and winding to 500 turns; result, a
flight of 250 yards, say. Arrived on the competition ground you put on
new rubber and wind to 750 turns, and expect a flight of a quarter of
a mile at least; result 70 yards, _measured in a straight line_ from
the starting-point.
14. Directional control is the most difficult problem to overcome with
any degree of success under all adverse conditions, and 15 per cent.,
in the writer's opinion, is far too low a percentage; by directional I
include flying in a straight line; personally I would mark for
all-round efficiency: (A) distance and stability, 50 per cent.; (B)
directional control, 30 per cent.; (C) duration of flight, 20 per
cent. In A the competitor would launch his model _in any direction_;
in B as directed by the judges. No separate flights required for C.
FOOTNOTES:
[48] The better way, undoubtedly, is to allow the competitor to choose
his direction, the starting "circle" only to be fixed.
[49] Or 10 per cent. for duration of flight.
[50] In another competition, held under the rules and regulations of
the Kite and Model Aeroplane Association for the best all-round model,
open to the world, for machines not under 2 sq. ft. of surface, the
tests (50 marks for each) were:--A. Longest flight in a straight line.
B. Circular flight to the right. C. Circular flight to the left. D.
Stability and landing after a flight. E. Excellence in building of the
model.
[51] On the assumption that the model will fly straight.
[52] If permitted to enter; if not see Fig. 53.
CHAPTER XIV.
USEFUL NOTES, TABLES, FORMULÆ, ETC.
§ 1. COMPARATIVE VELOCITIES.
Miles per hr. Feet per sec. Metres per sec.
10 = 14·7 = 4·470
15 = 22 = 6·705
20 = 29·4 = 8·940
25 = 36·7 = 11·176
30 = 44 = 13·411
35 = 51·3 = 15·646
§ 2. A metre = 39·37079 inches.
_In order to convert_:--
Metres into inches multiply by 39·37
" feet " 3·28
" yards " 1·09
" miles " 0·0006214
Miles per hour into ft. per min. multiply by 88·0
" min. " sec. " 88·0
" hr. into kilometres per hr. " 1·6093
" " metres per sec. " 0·44702
Pounds into grammes multiply by 453·593
" kilogrammes " 0·4536
§ 8. Total surface of a cylinder = circumference of base × height + 2
area of base.
Area of a circle = square of diameter × 0·7854.
Area of a circle = square of rad. × 3·14159.
Area of an ellipse = product of axes × 0·7854.
Circumference of a circle = diameter × 3·14159.
Solidity of a cylinder = height × area of base.
Area of a circular ring = sum of diameters × difference of diameters ×
0·7854.
For the area of a sector of a circle the rule is:--As 360 : number of
degrees in the angle of the sector :: area of the sector : area of
circle.
To find the area of a segment less than a semicircle:--Find the area
of the sector which has the same arc, and subtract the area of the
triangle formed by the radii and the chord.
The areas of corresponding figures are as the squares of corresponding
lengths.
§ 4. 1 mile = 1·609 kilometres.
1 kilometre = 1093 yards.
1 oz. = 28·35 grammes.
1 lb. = 453·59 "
1 lb. = 0·453 kilogrammes.
28 lb. = 12·7 "
112 lb. = 50·8 "
2240 lb. = 1016 "
1 kilogram = 2·2046 lb.
1 gram = 0·0022 lb.
1 sq. in. = 645 sq. millimetres.
1 sq. ft. = 0·0929 sq. metres.
1 sq. yard = 0·836 "
1 sq. metre = 10·764 sq. ft.
§ 5. One atmosphere = 14·7 lb. per sq. in. = 2116 lb. per sq. ft. =
760 millimetres of mercury.
A column of water 2·3 ft. high corresponds to a pressure of 1 lb. per
sq. in.
1 H.P. = 33,000 ft.-lb. per min. = 746 watts.
Volts × amperes = watts.
{pi} = 3·1416. _g_ = 32·182 ft. per sec. at London.
§ 6. TABLE OF EQUIVALENT INCLINATIONS.
Rise. Angle in Degs.
1 in 30 1·91
1 " 25 2·29
1 " 20 2·87
1 " 18 3·18
1 " 16 3·58
1 " 14 4·09
1 " 12 4·78
1 " 10 5·73
1 " 9 6·38
1 " 8 7·18
1 " 7 8·22
1 " 6 9·6
1 " 5 11·53
1 " 4 14·48
1 " 3 19·45
1 " 2 30·00
1 " {square root}2 45·00
§ 7. TABLE OF SKIN FRICTION.
Per sq. ft. for various speeds and surface lengths.
-----------------+-------------+-------------+-------------+------------
Velocity of Wind | 1 ft. Plane | 2 ft. Plane | 4 ft. Plane | 8 ft. Plane
-----------------+-------------+-------------+-------------+------------
10 | ·00112 | ·00105 | ·00101 | ·000967
15 | ·00237 | ·00226 | ·00215 | ·00205
20 | ·00402 | ·00384 | ·00365 | ·00349
25 | ·00606 | ·00579 | ·00551 | ·00527
30 | ·00850 | ·00810 | ·00772 | ·00736
35 | ·01130 | ·0108 | ·0103 | ·0098
-----------------+-------------+-------------+-------------+------------
This table is based on Dr. Zahm's experiments and the equation
_f_ = 0·00000778_l_^{-0·07}_v_^{1·85}
Where _f_ = skin friction per sq. ft.; _l_ = length of surface; _v_ =
velocity in feet per second.
In a biplane model the head resistance is probably from twelve to
fourteen times the skin friction; in a racing monoplane from six to
eight times.
§ 8. TABLE I.--(METALS).
--------------+------------+-----------------+-------------
Material | Specific | Elasticity E[A] | Tenacity
| Gravity | | per sq. in.
--------------+------------+-----------------+-------------
Magnesium | 1·74 | | {22,000-
| | | {32,000
Magnalium[B] | 2·4-2·57 | 10·2 |
Aluminium- } | | |
Copper[C]} | 2·82 | | 54,773
Aluminium | 2·6 | 11·1 | 26,535
Iron | 7·7 (about)| 29 | 54,000
Steel | 7·8 (about)| 32 | 100,000
Brass | 7·8-8·4 | 15 | 17,500
Copper | 8·8 | 36 | 33,000
Mild Steel | 7·8 | 30 | 60,000
| | |
--------------+------------+-----------------+-------------
[A] E in millions of lb. per sq. in.
[B] Magnalium is an alloy of magnesium and aluminium.
[C] Aluminium 94 per cent., copper 6 per cent. (the best
percentage), a 6 per cent. alloy thereby doubles the
tenacity of pure aluminium with but 5 per cent.
increase of density.
--------------+------------+-----------------+-------------
§ 9. TABLE II.--WIND PRESSURES.
_p_ = _kv²_.
_k_ coefficient (mean value taken) ·003 (miles per hour) = 0·0016 ft.
per second. _p_ = pressure in lb. per sq. ft. _v_ = velocity of wind.
Miles per hr. Ft. per sec. Lb. per sq. ft.
10 14·7 0·300
12 17·6 0·432
14 20·5 0·588
16 23·5 0·768
18 26·4 0·972
20 29·35 1·200
25 36·7 1·875
30 43·9 2·700
35 51·3 3·675
§ 10. Representing normal pressure on a plane surface by 1; pressure
on a rod (round section) is 0·6; on a symmetrical elliptic cross
section (axes 2:1) is 0·2 (approx.). Similar shape, but axes 6:1, and
edges sharpened (_see_ ch. ii., § 5), is only 0·05, or 1/20, and for
the body of minimum resistance (_see_ ch. ii., § 4) about 1/24.
§ 11. TABLE III.--LIFT AND DRIFT.
On a well shaped aerocurve or correctly designed cambered surface.
Aspect ratio 4·5.
Inclination. Ratio Lift to Drift.
0° 19:1
2·87° 15:1
3·58° 16:1
4·09° 14:1
4·78° 12:1
5·73° 9·6:1
7·18° 7·9:1
Wind velocity 40 miles per hour. (The above deduced from some
experiments of Sir Hiram Maxim.)
At a velocity of 30 miles an hour a good aerocurve should lift 21 oz.
to 24 oz. per sq. ft.
§ 12. TABLE IV.--LIFT AND DRIFT.
On a plane aerofoil.
N = P(2 sin {alpha}/1 + sin² {alpha})
Inclination. Ratio Lift to Drift.
1° 58·3:1
2° 29·2:1
3° 19·3:1
4° 14·3:1
5° 11·4:1
6° 9·5:1
7° 8·0:1
8° 7·0:1
9° 6·3:1
10° 5·7:1
P = 2_kd_ AV² sin {alpha}.
A useful formula for a single plane surface. P = pressure supporting
the plane in pounds per square foot, _k_ a constant = 0·003 in miles
per hour, _d_ = the density of the air.
A = the area of the plane, V relative velocity of translation through
the air, and {alpha} the angle of flight.
Transposing we have
AV² = P/(2_kd_ sin {alpha})
If P and {alpha} are constants; then AV² = a constant or area is
inversely as velocity squared. Increase of velocity meaning diminished
supporting surface (_and so far as supporting surface goes_), diminished
resistance and skin friction. It must be remembered, however, that while
the work of sustentation diminishes with the speed, the work of
penetration varies as the cube of the speed.
§ 13. TABLE V.--TIMBER.
Column Headings:
A. Material
B. Specific Gravity
C. Weight per Cub. Ft. in Lb.
D. Strength per Sq. In. in Lb.
E. Ultimate Breaking Load (Lb.) span 1' x 1" x 1"
F. Relative Resilience in Bending
G. Modulus of Elasticity in millions of Lb. per Sq. In. for Bending
H. Relative Value. Bending Strength compared with Weight
---------------+-----+-------+-------------+-------+-----+-----+----
A |B | C | D |E |F |G | H
---------------+-----+-------+-------------+-------+-----+-----+----
Ash | ·79 | 43-52 |14,000-17,000| 622 |4·69 |1·55 |13·0
Bamboo | | 25[A]| 6300[53] | |3·07 |3·20 |
Beech | ·69 | 43 |10,000-12,000| 850 | |1·65 |19·8
Birch | ·71 | 45 | 15,000 | 550 | |3·28 |12·2
Box |1·28 | 80 |20,000-23,000| 815 | | |10·2
Cork | ·24 | 15 | | | | |
Fir (Norway | | | | | | |
Spruce) | ·51 | 32 | 9,000-11,000| 450 |3·01 |1·70 |14·0
American | | | | | | |
Hickory | | 49 | 11,000 | 800 |3·47 |2·40 |16·3
Honduras | | | | | | |
Mahogany | ·56 | 35 | 20,000 | 750 |3·40 |1·60 |21·4
Maple | ·68 | 44 | 10,600 | 750 | | |17·0
American White | | | | | | |
Pine | ·42 | 25 | 11,800 | 450 |2·37 |1·39 |18·0
Lombardy Poplar| | 24 | 7,000 | 550 |2·89 | 0·77|22·9
American Yellow| | | | | | |
Poplar | | 44 | 10,000 | |3·63 |1·40 |
Satinwood | ·96 | 60 | |1,033 | | |17·2
Spruce | ·50 | 31 | 12,400 | 450 | | |14·5
Tubular Ash, | | | | | | |
_t_ = 1/8 _d_ | | 47 | | |3·50 |1·55 |
---------------+-----+-------+-------------+-------+-----+-----+----
_t_ = thickness: _d_ = diameter.
[A] Given elsewhere as 55 and 22,500 (_t_ = 1/3_d_), evidently
regarded as solid.
§ 14.--=Formula connecting the Weight Lifted in Pounds per Square Foot
and the Velocity.=--The empirical formula
W = (V²C)/_g_
Where W = weight lifted in lb. per sq. ft.
V = velocity in ft. per sec.
C = a constant = 0·025.
_g_ = 32·2, or 32 approx.
may be used for a thoroughly efficient model. This gives
(approximately)
1 lb. per sq. ft. lift at 25 miles an hour.
21 oz. " " 30 "
6 oz. " " 15 "
4 oz. " " 12 "
2·7 oz. " " 10 "
Remember the results work out in feet per second. To convert
(approximately) into miles per hour multiply by 2/3.
§ 15. =Formula connecting Models of Similar Design, but Different
Weights.=
D {proportional to} {square root}W.
or in models of _similar design_ the distances flown are proportional
to the square roots of the weights. (Derived from data obtained from
Clarke's flyers.)
For models from 1 oz. to 24-30 oz. the formula appears to hold very
well. For heavier models it appears to give the heavier model rather
too great a distance.
Since this was deduced a 1 oz. Clarke model of somewhat similar design
but longer rubber motor has flown 750 ft. at least; it is true the
design is not, strictly speaking, similar, but not too much reliance
must be placed on the above. The record for a 1 oz. model to date is
over 300 yards (with the wind, of course), say 750 ft. in calm air.
§ 16. =Power and Speed.=--The following formula, given by Mr. L. Blin
Desbleds, between these is--
W/W{0} = (3_v{0}_)/(4_v_) + ¼(_v_/_v{0}_)³.
Where _v{0}_ = speed of minimum power
W{0} = work done at speed _v{0}_.
W = work done at speed _v_.
Making _v_ = 2_v{0}_, i.e. doubling the speed of minimum power, and
substituting, we have finally
W = (2-3/8)W{0}
i.e. the speed of an aeroplane can be doubled by using a power 2-3/8
times as great as the original one. The "speed of minimum power" being
the speed at which the aeroplane must travel for the minimum
expenditure of power.
§ 17. The thrust of the propeller has evidently to balance the
Aerodynamic resistance = R
The head resistance (including skin friction) = S
Now according to Renard's theorem, the power absorbed by R + S is a
minimum when
S = R/3.
Having built a model, then, in which the total resistance
= (4/3)R.
This is the thrust which the propeller should be designed to give. Now
supposing the propeller's efficiency to be 80 per cent., then P--the
minimum propulsion power
= (4/3)R × 100/80 × 100/75 × _v_.
Where 25 per cent. is the slip of the screw, _v_ the velocity of the
aeroplane.
§ 18. =To determine experimentally the Static Thrust of a
Propeller.=--Useful for models intended to raise themselves from the
ground under their own power, and for helicopters.
The easiest way to do this is as follows: Mount the propeller on the
shaft of an electric motor, of sufficient power to give the propeller
1000 to 1500 revolutions per minute; a suitable accumulator or other
source of electric energy will be required, a speedometer or speed
counter, also a voltmeter and ammeter.
Place the motor in a pair of scales or on a suitable spring balance
(the former is preferable), the axis of the motor vertical, with the
propeller attached. Rotate the propeller so that the air current is
driven _upwards_. When the correct speed (as indicated by the speed
counter) has been attained, notice the difference in the readings if a
spring balance be used, or, if a pair of scales, place weights in the
scale pan until the downward thrust of the propeller is exactly
balanced. This gives you the thrust in ounces or pounds.
Note carefully the voltage and amperage, supposing it is 8 volts and
10 amperes = 80 watts.
Remove the propeller and note the volts and amperes consumed to run
the motor alone, i.e. to excite itself, and overcome friction and air
resistance; suppose this to be 8 volts and 2 amperes = 16; the
increased load when the propeller is on is therefore
80 - 16 = 64 watts.
All this increased power is not, however, expended on the propeller.
The lost power in the motor increases as C²R.
R = resistance of armature and C = current. If we deduct 10 per cent.
for this then the propeller is actually driven by 56 watts.
Now 746 watts = 1 h.p.
{therefore} 56/746 = 1/13 h.p. approx.
at the observed number of revolutions per minute.
§ 19. N.B.--The h.p. required to drive a propeller varies as the cube
of the revolutions.
_Proof._--Double the speed of the screw, then it strikes the air twice
as hard; it also strikes twice as much air, and the motor has to go
twice as fast to do it.
§ 20. To compare one model with another the formula
Weight × velocity (in ft. per sec.)/horse-power
is sometimes useful.
§ 21. =A Horse-power= is 33,000 lb. raised one foot in one minute, or
550 lb. one foot in one second.
A clockwork spring raised 1 lb. through 4½ ft. in 3 seconds. What
is its h.p.?
1 lb. through 4½ ft. in 3 seconds
is 1 lb. " 90 ft. " 1 minute.
{therefore} Work done is 90 ft.-lb.
= 90/33000 = 0·002727 h.p.
The weight of the spring was 6¾ oz. (this is taken from an actual
experiment), i.e. this motor develops power at the rate of 0·002727
h.p. for 3½ seconds only.
§ 22. =To Ascertain the H.P. of a Rubber Motor.= Supposing a propeller
wound up to 250 turns to run down in 15 seconds, i.e. at a mean speed
of 1200 revolutions per minute or 20 per second. Suppose the mean
thrust to be 2 oz., and let the pitch of the propeller be 1 foot. Then
the number of foot-pounds of energy developed
= (2 oz. × 1200 revols. × 1 ft. (pitch)) / 16 oz.
= 150 ft.-lb. per minute.
But the rubber motor runs down in 15 seconds.
{therefore} Energy really developed is
= (150 × 15) / 60 = 37·5 ft.-lb.
The motor develops power at rate of 150/33000 = 0·004545 h.p., but for
15 seconds only.
§ 23. =Foot-pounds of Energy in a Given Weight of Rubber=
(experimental determination of).
Length of rubber 36 yds.
Weight " 2-7/16 oz.
Number of turns = 200.
12 oz. were raised 19 ft. in 5 seconds.
i.e. ¾ lb. was raised 19 × 12 ft. in 1 minute.
i.e. 1 lb. was raised 19 × 3 × 3 ft. in 1 minute.
= 171 ft. in 1 minute.
i.e. 171 ft.-lb. of energy per minute. But actual time was 5 seconds.
{therefore} Actual energy developed by 2-7/16 oz. of rubber of 36
yards, i.e. 36 strands 1 yard each at 200 turns is
= 171/12 ft.-lb.
= 14¼ ft.-lb.
This allows nothing for friction or turning the axle on which the cord
was wound. Ball bearings were used; but the rubber was not new and
twenty turns were still unwound at the end of the experiment. Now
allowing for friction, etc. being the same as on an actual model, we
can take ¾ of a ft.-lb. for the unwound amount and estimate the
total energy as 15 ft.-lb. as a minimum. The energy actually developed
being at the rate of 0·0055 h.p., or 1/200 of a h.p. if supposed
uniform.
§ 24. The actual energy derivable from 1 lb. weight of rubber is
stated to be 300 ft.-lb. On this basis 2-7/16 oz. should be capable of
giving 45·7 ft.-lb. of energy, i.e. three times the amount given
above. Now the motor-rubber not lubricated was only given 200
turns--lubricated 400 could have been given it, 600 probably before
rupture--and the energy then derivable would certainly have been
approximating to 45 ft.-lb., i.e. 36·25. Now on the basis of 300
ft.-lb. per lb. a weight of ½ oz. (the amount of rubber carried in
"one-ouncers") gives 9 ft.-lb. of energy. Now assuming the gliding
angle (including weight of propellers) to be 1 in 8; a perfectly
efficient model should be capable of flying eight times as great a
distance in a horizontal direction as the energy in the rubber motor
would lift it vertically. Now 9 ft.-lb. of energy will lift 1 oz. 154
ft. Therefore theoretically it will drive it a distance (in yards) of
(8 × 154)/3 = 410·6 yards.
Now the greatest distance that a 1 oz. model has flown in perfectly
calm air (which never exists) is not known. Flying with the wind 500
yards is claimed. Admitting this what allowance shall we make for the
wind; supposing we deduct half this, viz. 250 yards. Then, on this
assumption, the efficiency of this "one ouncer" works out (in
perfectly still air) at 61 per cent.
The gliding angle assumption of 1 in 8 is rather a high one, possibly
too high; all the writer desires to show is the method of working out.
Mr. T.W.K. Clarke informs me that in his one-ouncers the gliding
angle is about 1 in 5.
§ 25. =To Test Different Motors or Different Powers of the Same Kind
of Motor.=--Test them on the same machine, and do not use different
motors or different powers on different machines.
§ 26. =Efficiency of a Model.=--The efficiency of a model depends on
the weight carried per h.p.
§ 27. =Efficiency of Design.=--The efficiency of some particular
design depends on the amount of supporting surface necessary at a
given speed.
§ 28. =Naphtha Engines=, that is, engines made on the principle of the
steam engine, but which use a light spirit of petrol or similar agent
in their generator instead of water with the same amount of heat, will
develop twice as much energy as in the case of the ordinary steam
engine.
§ 29.=Petrol Motors.=
Horse-power. No. of Cylinders. Weight.
¼ Single 4½ lb.
½ to ¾ " 6½ "
1½ Double 9 "
§ 30. =The Horse-power of Model Petrol Motors.=--Formula for rating of
the above.
(R.P.M. = revolutions per minute.)
H.P. = ((Bore)² × stroke × no. of cylinders × R.P.M.)/12,000
If the right-hand side of the equation gives a less h.p. than that
stated for some particular motor, then it follows that the h.p. of the
motor has been over-estimated.
[Illustration: FIG. 56.]
§ 30A. =Relation between Static Thrust of Propeller and Total Weight
of Model.=--The thrust should be approx. = ¼ of the weight.
§ 31. =How to find the Height of an Inaccessible Object by Means of
Three Observations taken on the Ground (supposed flat) in the same
Straight Line.=--Let A, C, B be the angular elevations of the object
D, as seen from these points, taken in the same straight line. Let the
distances B C, C A and A B be _a_, _b_, _c_ respectively. And let
required height P D = _h_; then by trigonometry we have (see Fig. 56)
_h²_ = _abc_/(_a_ cot²A - _c_ cot²C + _b_ cot²B).
§ 32. =Formula= for calculating the I.H.P. (indicated horse-power) of
a single-cylinder double-acting steam-engine.
Indicated h.p. means the h.p. actually exerted by the steam in the
cylinder without taking into account engine friction. Brake h.p. or
effective h.p. is the actual h.p. delivered by the crank shaft of the
engine.
I.H.P. = (2 × S × R × A × P)/33,000.
Where S = stroke in feet.
R = revolutions per minute.
A = area of piston in inches.
P = mean pressure in lb. exerted per sq. in. on the piston.
The only difficulty is the mean effective pressure; this can be found
approximately by the following rule and accompanying table.
TABLE VI.
---------+----------+---------+----------+---------+---------
Cut-off | Constant | Cut-off | Constant | Cut-off | Constant
---------+----------+---------+----------+---------+---------
1/6 | ·566 | 3/8 | ·771 | 2/3 | ·917
1/5 | ·603 | ·4 | ·789 | ·7 | ·926
1/4 | ·659 | 1/2 | ·847 | 3/4 | ·937
·3 | ·708 | ·6 | ·895 | ·8 | ·944
1/3 | ·743 | 5/8 | ·904 | 7/8 | ·951
---------+----------+---------+----------+---------+---------
Rule.--"Add 14·7 to gauge pressure of boiler, this giving 'absolute
steam pressure,' multiply this sum by the number opposite the fraction
representing the point of cut-off in the cylinder in accompanying
table. Subtract 17 from the product and multiply the remainder by 0·9.
The result will be very nearly the M.E.P." (R.M. de Vignier.)
FOOTNOTE:
[53] Given elsewhere as 55 and 22,500 (_t_ = 1/3 _d_), evidently
regarded as solid.
APPENDIX A.
SOME MODELS WHICH HAVE WON MEDALS AT OPEN COMPETITIONS.
[Illustration: FIG. 57.--THE G.P.B. SMITH MODEL.]
The model shown in Fig. 57 has won more competition medals than any
other. It is a thoroughly well designed[54] and well constructed
model. Originally a very slow flyer, the design has been simplified,
and although by no means a fast flyer, its speed has been much
accelerated. Originally a one-propeller machine, it has latterly been
fitted with twin propellers, with the idea of obtaining more
directional control; but in the writer's opinion, speaking from
personal observation, with but little, if any, success. The steering
of the model is effected by canting the elevator. Originally the
machine had ailerons for the purpose, but these were removed owing, I
understand, to their retarding the speed of the machine.
In every competition in which this machine has been entered it has
always gained very high marks for stability.
[Illustration: FIG. 58.--THE GORDON-JONES DIHEDRAL BIPLANE.]
Up to the time of writing it has not been provided with anything in
the nature of fins or rudder.
Fig. 58 is a biplane very much after the type of the model just
alluded to, but the one straight and one curved aerofoil surfaces are
here replaced by two parallel aerofoils set on a dihedral angle. The
large size of the propeller should be noted; with this the writer is
in complete agreement. He has not unfortunately seen this model in
actual flight.
The scientifically designed and beautifully made models illustrated in
Fig. 59 are so well known that any remarks on them appear
superfluous. Their efficiency, so far as their supporting area goes,
is of the highest, as much as 21 oz. per square foot having been
carried.
[Illustration: FIG. 59.--MESSRS. T.W.K. CLARKE AND CO.'S MODEL
FLYERS.]
For illustrations, etc., of the Fleming-Williams model, _see_ ch. v.,
§ 23.
(Fig. 60.) This is another well-constructed and efficient model, the
shape and character of the aerofoil surfaces much resembling those of
the French toy monoplane AL-MA (see § 4, ch. vii.), but they are
supported and held in position by quite a different method, a neat
little device enabling the front plane to become partly detached on
collision with any obstacle. The model is provided with a keel (below
the centre of gravity), and rudder for steering; in fact, this machine
especially claims certainty of directional control. The writer has
seen a number of flights by this model, but it experiences, like other
models, the greatest difficulty in keeping straight if the conditions
be adverse.
The model which will do this is, in his opinion, yet to be evolved.
The small size of the propellers is, of course, in total disagreement
with the author's ideas. All the same, the model is in many respects
an excellent one, and has flown over 300 yards at the time of writing.
[Illustration: FIG. 60.--THE DING SAYERS MONOPLANE.]
More than a year ago the author made a number of models with
triangular-shaped aerofoils, using umbrella ribs for the leading edge
and steel piano wire for the trailing, but has latterly used aerofoils
of the elongated ellipse shape.
Fig. 61 is an illustration of one of the author's latest models which
won a Bronze Medal at the Long Distance Open Competition, held at the
Crystal Palace on July 27, 1910, the largest and most keenly contested
competition held up to that date.
The best and straightest flight against the wind was made by this
model.
On the morning of the competition a flight of about 320 yards
(measured in a straight line) was made on Mitcham Common, the model
being launched against the wind so as to gain altitude, and then
flying away with the breeze behind the writer. Duration of flight 50
seconds. The following are the chief particulars of the
model:--Weight, 7½ oz. Area of supporting surface, 1-1/3 sq. ft.
Total length, 4 ft. Span of main aerofoil, 25 in. Aspect ratio, 4 : 1.
Diameter of propeller, 14 in. Two strand geared rubber motor, carrying
altogether 28 strands of 1/16 square rubber cord 43 in. long. The
propeller was originally a Venna, but with the weight reduced by
one-third, and considerable alteration made in its central contours.
The front skid of steel pianoforte wire, the rear of jointless cane
wire tipped; the rear skid was a necessity in order to protect the
delicate gearing mechanism, the weight of which was reduced to a
minimum.
[Illustration: FIG. 61.--THE AUTHOR'S "GRASSHOPPER" MODEL.]
The very large diameter of the propeller should be noted, being 56
per cent. of the span. The fin, high above the centre of gravity, was
so placed for transverse stability and direction. At the rear of the
fin was a rudder. The small amount of rubber carried (for a long
distance machine) should also be noted, especially when allowing for
friction in gearing, etc.
The central rod was a penny bamboo cane, the large aerofoil of
jointless cane and Hart's fabric, and the front aerofoil of steel wire
surfaced with the same material.
LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, GREAT WINDMILL
STREET, W., AND DUKE STREET, STAMFORD STREET, S.E.
FOOTNOTE:
[54] The design is patented.
_October, 1910_
A SHORT LIST OF
SCIENTIFIC BOOKS
PUBLISHED AND SOLD BY
E. & F.N. SPON, Limited,
57 Haymarket, London, S.W.
SOLE ENGLISH AGENTS for the Books of--
MYRON C. CLARK, NEW YORK
THE BUSINESS CODE COMPANY, CHICAGO
SPON & CHAMBERLAIN, NEW YORK
PAGE
AERONAUTICS 2
AGRICULTURE 2
ARCHITECTURE 3
ARTILLERY 5
BRIDGES AND ROOFS 5
BUILDING 3
CEMENT AND CONCRETE 7
CIVIL ENGINEERING 8
DICTIONARIES 11
DOMESTIC ECONOMY 12
DRAWING 13
ELECTRICAL ENGINEERING 14
FOREIGN EXCHANGE 19
GAS AND OIL ENGINES 20
GAS LIGHTING 20
HISTORICAL; BIOGRAPHICAL 21
HOROLOGY 22
HYDRAULICS 22
INDUSTRIAL CHEMISTRY 24
IRRIGATION 27
LOGARITHM TABLES 28
MANUFACTURES 24
MARINE ENGINEERING 28
MATERIALS 30
MATHEMATICS 31
MECHANICAL ENGINEERING 33
METALLURGY 36
METRIC TABLES 38
MINERALOGY AND MINING 38
MUNICIPAL ENGINEERING 45
NAVAL ARCHITECTURE 28
ORGANISATION 40
PHYSICS 41
PRICE BOOKS 42
RAILWAY ENGINEERING 43
SANITATION 45
STRUCTURAL DESIGN 45
TELEGRAPH CODES 47
WARMING; VENTILATION 47
WATER SUPPLY 48
WORKSHOP PRACTICE 49
USEFUL TABLES 52
MISCELLANEOUS 53
_Full particulars post free on application.
All books are bound in cloth unless otherwise stated._
_NOTE: The Prices in this Catalogue apply to books sold in
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AERONAUTICS
=The Atmosphere=: its characteristics and dynamics. By F.J.B.
CORDEIRO. With 35 illus. 129 pp. medium 8vo. (_New York, 1910_)
_net_ 10 6
=Theory and Practice of Model Aeroplaning.= By V.E. JOHNSON. 61
illus. 150 pp. crown 8vo. (_1910_)
_net_ 3 6
=How to Build a 20-ft. Biplane Glider.= By A.P. MORGAN. 31
illus. 60 pp. crown 8vo, limp. (S. & C. SERIES, NO. 14.) (_New
York, 1909_)
_net_ 1 6
=Flight-Velocity.= By A. SAMUELSON. 4 plates, 42 pp. 8vo,
sewed. (_1906_)
_net_ 2 0
=Resistance of Air and the Question of Flying.= By A.
SAMUELSON. 23 illus. 36 pp. 8vo, sewed. (_1905_)
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AGRICULTURE.
=Hemp.= A Practical Treatise on the Culture for Seed and Fibre.
By S.S. BOYCE. 13 illus. 112 pp. crown 8vo. (_New York, 1900_)
_net_ 2 0
=The Fertilisation of Tea.= By G.A. COWIE. With 17 illus. 68
pp. crown 8vo, sewed. (_1908_)
_net_ 2 6
=Farm Drainage.= By H.F. FRENCH. 100 illus. 284 pp. crown 8vo.
(_New York, 1904_)
_net_ 4 6
=Talks on Manures.= By J. HARRIS. New edition, 366 pp. crown
8vo. (_New York, 1893_)
_net_ 6 6
=Coffee=, its Culture and Commerce in all Countries. By C.G.W.
LOCK. 11 plates, 274 pp. crown 8vo. (_1888_)
12 6
=Sugar, a Handbook for Planters and Refiners.= By the late J.A.
R. NEWLANDS and B.E.R. NEWLANDS. 236 illus. 876 pp. demy 8vo.
(_London, 1909_)
_net_ 1 5 0
=Hops=, their Cultivation, Commerce and Uses. By P.L. SIMMONDS.
143 pp. crown 8vo. (_1877_)
4 6
=The Future of Cocoa-Planting=. By H. HAMEL SMITH. With
illustrations, 95 pp. crown 8vo, sewed. (_1908_)
_net_ 1 0
=Estate Fences=, their Choice, Construction and Cost. By A.
VERNON. Re-issue, 150 illus. 420 pp. 8vo. (_1909_)
_net_ 8 6
ARCHITECTURE AND BUILDING.
=The Hydropathic Establishment and its Baths.= By R.O. ALLSOP.
8 plates, 107 pp. demy 8vo. (_1891_)
5 0
=The Turkish Bath=, its Design and Construction. By R.O.
ALLSOP. 27 illus. 152 pp. demy 8vo. (_1890_)
6 0
=Public Abattoirs=, their Planning, Design and Equipment. By
R.S. AYLING. 33 plates, 100 pp. demy 4to. (_1908_)
_net_ 8 6
=The Builder's Clerk.= By T. BALES. Second edition, 92 pp.
fcap. 8vo. (_1904_)
1 6
=Glossary of Technical Terms= used in Architecture and the
Building Trades. By G.J. BURNS. 136 pp. crown 8vo. (_1895_)
3 6
=Chimney Design and Theory.= By W.W. CHRISTIE. Second edition,
54 illus. 200 pp. crown 8vo. (_New York, 1902_)
_net_ 12 6
=Approximate Estimates.= By T.E. COLEMAN. Third edition, 481
pp. oblong 32mo, leather. (_1907_)
_net_ 5 0
=Stable Sanitation and Construction.= By T.E. COLEMAN. 183
illus. 226 pp. crown 8vo. (_1897_)
_net_ 6 0
=Architectural Examples= in Brick, Stone, Wood and Iron. By W.
FULLERTON. Third edition, 245 plates, 254 pp. demy 4to.
(_1908_)
_net_ 15 0
=Bricklaying System.= By F.B. GILBRETH. Fully illustrated, 321
pp. 8vo. (_New York, 1909_)
_net_ 12 6
=Field System.= By F.B. GILBRETH. 194 pp. 12mo leather. (_New
York, 1908_)
_net_ 12 6
=The Building Trades Pocket Book.= Compiled by R. HALL. 12mo.
With interchangeable diary
_net_ 1 6
Ditto ditto, in leather
_net_ 2 6
=The Clerk of Works' Vade Mecum.= By G.G. HOSKINS. Seventh
edition, 52 pp. fcap. 8vo. (_1901_)
1 6
=A Handbook of Formulæ, Tables, and Memoranda=, for
Architectural Surveyors and others engaged in Building. By J.T.
HURST. Fifteenth edition, 512 pp. royal 32mo, roan. (_1905_)
_net_ 5 0
=Quantity Surveying=, for the Use of Surveyors, Architects,
Engineers and Builders. By J. LEANING. Fifth edition, 936 pp.
demy 8vo. (_1904_)
_net_ 1 5 0
=Obstruction to Light.= A Graphic Method of determining
Problems of Ancient Lights. By H.B. MOLESWORTH. 9 folding
plates, 4to. (_1902_)
_net_ 6 0
=Suburban Houses.= A series of practical plans. By J.H.
PEARSON. 46 plates and 12 pp. text, crown 4to. (_1905_)
_net_ 7 6
=Solid Bitumens=, their Physical and Chemical Properties and
Chemical Analysis. By S.F. PECKHAM. 23 illus. 324 pp. 8vo.
(_New York, 1909_)
_net_ 1 1 0
=Roman Architecture, Sculpture and Ornament.= By G.B. PIRANESI.
200 plates, reproduced in facsimile from the original. 2 vols.
Imperial folio, in wrappers. (_1900_)
_net_ 2 2 0
=The Seven Periods of English Architecture=, defined and
illustrated. By E. SHARPE. Third edition, 20 steel plates,
royal 8vo. (_1888_)
12 6
=Our Factories, Workshops and Warehouses=, their Sanitary and
Fire-Resisting Arrangements. By B.H. THWAITE. 183 illus. 282
pp. crown 8vo. (_1882_)
9 0
=Elementary Principles of Carpentry.= By T. TREDGOLD and J.T.
HURST. Eleventh edition, 48 plates, 517 pp. crown 8vo. (_1904_)
12 6
=Practical Stair Building and Handrailing.= By W.H. WOOD. 32
plates, 91 pp. crown 4to. (_1894_)
10 6
=Spons' Architects' and Builders' Pocket Price-Book=,
Memoranda, Tables and Prices. Edited by CLYDE YOUNG. Revised by
STANFORD M. BROOKS. Illustrated, 552 pp. 16mo, leather cloth
(size 6½ in. by 3¾ in. by ½ in. thick). Issued annually
_net_ 3 0
=Heating Engineers' Quantities.= By W.L. WHITE and G.M. WHITE.
4 plates, 33 pp. folio. (_1910_)
_net_ 10 6
ARTILLERY.
=Guns and Gun Making Material.= By G. EDE. Crown 8vo. (_1889_)
6 0
=Treatise on Application of Wire to Construction of Ordnance.=
By J.A. LONGRIDGE. 180 pp. 8vo. (_1884_)
1 5 0
=The Progress of Artillery: Naval Guns.= By J.A. LONGRIDGE.
8vo, sewed. (_1896_)
2 0
=The Field Gun of the Future.= By J.A. LONGRIDGE. 8vo, sewed.
(_1892_)
2 6
BRIDGES, ARCHES, ROOFS, AND STRUCTURAL DESIGN.
=Strains in Ironwork.= By HENRY ADAMS. Fourth edition, 8 plates, 65
pp. crown 8vo. (_1904_)
5 0
=The Practical Designing of Structural Ironwork.= By HENRY ADAMS. 13
plates, 194 pp. 8vo. (_1894_)
8 6
=Designing Ironwork.= By HENRY ADAMS. Second series. 8vo, sewed.
Part I. A Steel Box Girder. (_1894_)
_net_ 0 9
" II. Built-up Steel Stanchions. (_1901_)
_net_ 1 3
" III. Cisterns and Tanks. (_1902_)
_net_ 1 0
" IV. A Fireproof Floor. (_1903_)
_net_ 1 0
=A Practical Treatise on Segmental and Elliptical Oblique or Skew
Arches.= By G.J. BELL. Second edition, 17 plates, 125 pp. royal 8vo.
(_1906_)
_net_ 1 1 0
=Economics of Construction in relation to Framed Structures.= By R.H.
Bow. Third thousand, 16 plates, 88 pp. 8vo. (1873)
5 0
=Theory of Voussoir Arches.= By Prof. W. CAIN. Third edition, 201 pp.
18mo, boards. (_New York, 1905_)
_net_ 2 0
=New Formulæ for the Loads and Deflections= of Solid Beams and
Girders. By W. DONALDSON. Second edition, 8vo. (_1872_)
4 6
=Plate Girder Railway Bridges.= By M. FITZMAURICE. 4 plates, 104 pp.
8vo. (_1895_)
6 0
=Pocket Book of Calculations in Stresses.= By E.M. GEORGE. 66 illus.
140 pp. royal 32mo, half roan. (_1895_)
3 6
=Strains on Braced Iron Arches= and Arched Iron Bridges. By A.S.
HEAFORD. 39 pp. 8vo. (_1883_)
6 0
=Tables for Roof Framing.= By G.D. INSKIP. Second edition, 451 pp.
8vo, leather. (_New York, 1905_)
_net_ 12 6
=Stresses in Girder and Roof Frames,= for both dead and live loads,
by simple Multiplication, etc. By F.R. JOHNSON. 28 plates, 215 pp.
crown 8vo. (_1894_)
6 0
=A Graphical Method for Swing Bridges.= By B.F. LA RUE. 4 plates, 104
pp. 18mo, boards. (_New York, 1892_)
_net_ 2 0
=Notes on Cylinder Bridge Piers= and the Well System of Foundations.
By J. NEWMAN. 144 pp. 8vo. (_1893_)
6 0
=A New Method of Graphic Statics= applied in the Construction of
Wrought Iron Girders. By E. OLANDER. 16 plates, small folio. (_1887_)
10 6
=Reference Book for Statical Calculations.= By F. RUFF. With diagrams,
140 pp. crown 8vo. (_1906_)
_net_ 5 0
=The Strength and Proportion of Riveted Joints.= By B.B. STONEY. 87
pp. 8vo. (_1885_)
5 0
=The Anatomy of Bridgework.= By W.H. THORPE. 103 illus. 190 pp. crown
8vo. (_1906_)
_net_ 6 0
CEMENT AND CONCRETE.
=Portland Cement:= its Manufacture, Testing and Use. By D.B. BUTLER.
Second edition, 97 illus. 396 pp. demy 8vo. (_1905_)
_net_ 16 0
=Theory of Steel-Concrete Arches= and of Vaulted Structures. By W.
CAIN. Fourth edition, 27 illus. 212 pp. 18mo, boards. (_New York,
1906_)
_net_ 2 0
=Cement Users' and Buyers' Guide.= By CALCARE. 115 pp. 32mo, cloth.
(_1901_)
_net_ 1 6
=Diagrams for Designing Reinforced Concrete Structures.= By G.F.
DODGE. 31 illus. 104 pp. oblong folio. (_New York, 1910_)
_net_ 17 0
=Cements, Mortars, and Concretes;= their Physical properties. By M.S.
FALK. 78 illus. 176 pp. 8vo. (_New York, 1904_)
_net_ 10 6
=Concrete Construction, Methods and Cost.= By H.P. GILLETTE and C.S.
HILL. 310 illus. 690 pp. 8vo. (_New York, 1908_)
_net_ 1 1 0
=Engineers' Pocket-Book of Reinforced Concrete.= By E.L. HEIDENREICH.
164 illus. 364 pp. crown 8vo, leather, gilt edges. (_New York, 1909_)
_net_ 12 6
=Concrete Inspection.= By C.S. HILL. Illustrated, 179 pp. 12mo. (_New
York, 1909_)
_net_ 4 6
=Reinforced Concrete.= By E. MCCULLOCH. 28 illus. 128 pp. crown 8vo.
(_New York, 1908_)
_net_ 6 6
=Concrete and Reinforced Concrete.= By H.A. REID. 715 illus. 884 pp.
royal 8vo. (_New York, 1907_)
_net_ 21 0
=Theory and Design of Reinforced Concrete Arches.= By A. REUTERDAHL.
41 illus. 126 pp. 8vo. (_New York, 1908_)
_net_ 8 6
=Practical Cement Testing.= By W.P. TAYLOR. With 142 illus. 329 pp.
demy 8vo. (New York, 1906)
_net_ 12 6
=Concrete Bridges and Culverts.= By H.G. TYRRELL. 66 illus. 251 pp.
crown 8vo, leather
_net_ 12 6
CIVIL ENGINEERING.
CANALS, SURVEYING.
(_See also_ IRRIGATION _and_ WATER SUPPLY.)
=Practical Hints to Young Engineers Employed on Indian Railways.= By
A.W.C. ADDIS. With 14 illus. 154 pp. 12mo. (_1910_)
_net_ 3 6
=Levelling,= Barometric, Trigonometric and Spirit. By I.O. BAKER.
Second edition, 15 illus. 145 pp. 18mo, boards. (_New York, 1903_) ..
_net_ 2 0
=Notes on Instruments= best suited for Engineering Field Work in India
and the Colonies. By W.G. BLIGH. 65 illus. 218 pp. 8vo. (_1899_)
7 6
=The Sextant and other Reflecting Mathematical Instruments.= By
F.R. BRAINARD. 33 illus. 120 pp. 18mo, boards. (_New York, 1891_)
_net_ 2 0
=Practical Designing of Retaining Walls.= By Prof. W. CAIN. Fifth
edition, 14 illus. 172 pp. 18mo, boards. (_New York, 1908_)
_net_ 2 0
=The Maintenance of Macadamised Roads.= By T. CODRINGTON. Second
edition, 186 pp. 8vo. (_1892_)
7 6
=Retaining Walls in Theory and Practice.= By T.E. COLEMAN. 104 illus.
160 pp. crown 8vo. (_1909_)
_net_ 5 0
=The Barometrical Determination of Heights.= By F.J.B. CORDEIRO.
Crown 8vo, limp leather. (_New York, 1898_)
_net_ 4 6
=On Curved Masonry Dams.= By W.B. COVENTRY. 8vo, sewed. (_1894_)
2 0
=A Practical Method of Determining the Profile of a Masonry Dam.= By
W.B. COVENTRY. 8vo, sewed. (_1894_)
2 6
=The Stresses on Masonry Dams= (oblique sections). By W.B. COVENTRY.
8vo, sewed. (_1894_)
2 0
=Tables for facilitating the Calculation of Earthworks.= By D.
CUNNINGHAM. 120 pp. royal 8vo
10 6
=Handbook of Cost Data for Contractors and Engineers.= By H.P.
GILLETTE. 1854 pp. crown 8vo, leather, gilt edges. (_New York, 1910_)
_net_ 1 1 0
=Rock Excavation, Methods and Cost.= By H.P. GILLETTE. 56 illus. 376
pp. crown 8vo. (_New York, 1904_)
_net_ 12 6
=High Masonry Dams.= By E.S. GOULD. With illus. 88 pp. 18mo, boards.
(_New York, 1897_)
_net_ 2 0
=Grace's Tables for Curves,= with hints to young engineers. 8 figures,
43 pp. oblong 8vo. (_1908_)
_net_ 5 0
=Grace's Earthwork Tables.= 36 double-page tables, 4to. (_1907_)
_net_ 12 6
=Railway Tunnelling= in Heavy Ground. By C. GRIPPER. 3 plates, 66 pp.
royal 8vo. (_1879_)
7 6
=Levelling and its General Application.= By T. HOLLOWAY. Second
edition, 53 illus. 147 pp. 8vo. (_1895_)
5 0
=Waterways and Water Transport= in different Countries. By J.S. JEANS.
55 illus. 520 pp. 8vo. (_1890_)
_net_ 9 0
=Table of Barometrical Heights to 20,000 Feet.= By W.H. MACKESY, with
some practical suggestions by Sir Guildford Molesworth. 1 plate, 24
pp. royal 32mo. (_1882_)
3 0
=Aid Book to Engineering Enterprise.= By E. MATHESON. Third edition,
illustrated, 916 pp. medium 8vo, buckram. (_1898_)
1 4 0
=A Treatise on Surveying.= By R.E. MIDDLETON and O. CHADWICK. Second
edition, royal 8vo.
Part I. 11 plates, 296 pp. (_1904_)
10 6
" II. Fully illustrated, 334 pp. (_1906_)
10 6
=A Pocket Book of Useful Formulæ and Memoranda,= for Civil and
Mechanical Engineers. By Sir G.L. MOLESWORTH and H.B. MOLESWORTH. With
an Electrical Supplement by W.H. MOLESWORTH. Twenty-sixth edition, 760
illus. 901 pp. royal 32mo, French morocco, gilt edges. (_1908_)
_net_ 5 0
=The Pocket Books of Sir G.L. Molesworth and J.T. Hurst,= printed on
India paper and bound in one vol. Royal 32mo, russia, gilt edges.
_net_ 10 6
=Metallic Structures: Corrosion and Fouling and their Prevention.= By
J. NEWMAN. Illustrated, 385 pp. crown 8vo. (_1896_)
9 0
=Scamping Tricks and Odd Knowledge= occasionally practised upon Public
Works. By J. NEWMAN. New impression, 129 pp. crown 8vo. (_1908_)
_net_ 2 0
=Earthwork Slips and Subsidences= on Public Works. By J. NEWMAN.
240 pp. crown 8vo. (_1890_)
7 6
=Co-ordinate Geometry= as applied to Land Surveying. By W. PILKINGTON.
5 illus. 44 pp. 12mo. (_1909_)
_net_ 1 6
=Diagrams for the Graphic Calculation of Earthwork Quantities.= By
A.H. ROBERTS. Ten cards, fcap. in cloth case
_net_ 10 6
=Pioneering.= By F. SHELFORD, illustrated. 88 pp. crown 8vo. (_1909_)
_net_ 3 0
=Topographical Surveying.= By G.J. SPECHT. Second edition, 2 plates
and 28 illus. 210 pp. 18mo, boards. (_New York, 1898_)
_net_ 2 0
=Spons' Dictionary of Engineering,= Civil, Mechanical, Military and
Naval. 10,000 illus. 4300 pp. super royal 8vo. (_1874, Supplement
issued in 1881_). Complete with Supplement, in 11 divisions
_net_ 3 10 0
Ditto ditto in 4 vols.
_net_ 3 3 0
=Surveying and Levelling Instruments.= By W.F. STANLEY. Third edition,
372 illus. 562 pp. crown 8vo. (_1901_)
7 6
=Surveyor's Handbook.= By T.U. TAYLOR. 116 illus. 310 pp. crown 8vo,
leather, gilt edges. (_New York, 1908_)
_net_ 8 6
=Logarithmic Land Measurement.= By J. WALLACE. 32 pp. royal 8vo.
(_1910_)
_net_ 5 0
=Hints on Levelling Operations.= By W.H. WELLS. Second edition, 8vo,
sewed. (_1890_)
_net_ 1 0
=The Drainage of Fens and Low Lands= by Gravitation and Steam Power.
By W.H. WHEELER. 8 plates, 175 pp. 8vo. (_1888_)
12 6
=Stadia Surveying,= the theory of Stadia Measurements. By A. WINSLOW.
Fifth edition, 148 pp. 18mo, boards. (_New York, 1902_)
_net_ 2 0
=Handbook on Tacheometrical Surveying.= By C. XYDIS. 55 illus. 3
plates, 63 pp. 8vo. (_1909_)
_net_ 6 0
DICTIONARIES.
=Technological Dictionary in the English, Spanish, German and French
Languages.= By D. CARLOS HUELIN Y ARSSU. Crown 8vo.
Vol. I. ENGLISH-SPANISH-GERMAN-FRENCH.
609 pp. (_1906_)
_net_ 10 6
Vol. II. GERMAN-ENGLISH-FRENCH-SPANISH.
720 pp. (_1908_)
_net_ 10 6
Vol. III. FRENCH-GERMAN-SPANISH-ENGLISH.
In preparation.
Vol. IV. SPANISH-FRENCH-ENGLISH-GERMAN.
750 pp. (_1910_)
_net_ 10 6
=English-French and French-English Dictionary of the Motor-Car, Cycle
and Boat.= By F. LUCAS. 171 pp. crown 8vo. (_1905_)
_net_ 5 0
=Spanish-English Dictionary of Mining Terms.= By F. LUCAS. 78 pp. 8vo.
(_1905_)
_net_ 5 0
=English-Russian and Russian-English Engineering Dictionary.= By L.
MEYCLIAR. 100 pp. 16mo. (_1909_)
_net_ 2 6
=Reed's Polyglot Guide to the Marine Engine,= in English, French,
German and Norsk. Second edition, oblong 8vo. (_1900_).
_net_ 6 0
DOMESTIC ECONOMY.
=Food Adulteration and its Detection.= By J.P. BATTERSHALL. 12 plates,
328 pp. demy 8vo. (_New York, 1887_)
15 0
=How to Check Electricity Bills.= By S.W. BORDEN. 41 illus. 54 pp.
crown 8vo. (_New York, 1907_)
_net_ 2 0
=Practical Hints on Taking a House.= By H.P. BOULNOIS. 71 pp. 18mo.
(_1885_)
1 6
=The Cooking Range,= its Failings and Remedies. By F. DYE. 52 pp.
fcap. 8vo, sewed. (_1888_)
0 6
=The Kitchen Boiler and Water Pipes.= By H. GRIMSHAW. 8vo, sewed.
(_1887_)
_net_ 1 0
=Cookery and Domestic Management,= including economic and middle class
Practical Cookery. By K. MELLISH. 56 coloured plates and 441 illus.
987 pp. super-royal 8vo. (_1901_)
_net_ 16 0
=Spons' Household Manual.= 250 illus. 1043 pp. demy 8vo. (_1902_)
7 6
Ditto ditto half-bound French morocco
9 0
=Handbook of Sanitary Information= for Householders. By R.S. TRACY. 33
illus. 114 pp. 18mo. (_New York, 1900_)
2 6
DRAWING.
=The Ornamental Penman's,= Engraver's and Sign Writer's Pocket Book of
Alphabets. By B. ALEXANDER. Oblong 12mo, sewed
0 6
=The Draughtsman's Handbook= of Plan and Map Drawing. By G.G. ANDRE.
87 illus. and 34 plain and coloured plates, 162 pp. crown 4to.
(_1891_)
9 0
=Slide Valve Diagrams:= a French Method for their Construction. By L.
BANKSON. 18mo, boards. (_New York, 1892_) . . .
_net_ 2 0
=A System of Easy Lettering.= By J.H. CROMWELL. With Supplement by G.
MARTIN. Sixth thousand, oblong 8vo. (_New York, 1900_)
_net_ 2 0
=Plane Geometrical Drawing.= BY R.C. FAWDRY. Illustrated, 185 pp.
crown 8vo. (_1901_)
_net_ 3 0
=Twelve Plates on Projection Drawing.= By O. GUETH. Oblong 4to. (_New
York, 1903_)
_net_ 3 0
=Hints on Architectural Draughtsmanship.= By G.W.T. HALLATT. Fourth
edition, 80 pp. 18mo. (_1906_)
_net_ 1 6
=A First Course of Mechanical Drawing= (Tracing). By G. HALLIDAY.
Oblong 4to, sewed
2 0
=Drawings for Medium-sized Repetition Work.= By R.D. SPINNEY. With 47
illus. 130 pp. 8vo. (_1909_)
_net_ 3 6
=Mathematical Drawing Instruments.= By W.F. STANLEY. Seventh edition,
265 illus. 370 pp. crown 8vo. (_1900_)
5 0
ELECTRICAL ENGINEERING.
=Practical Electric Bell Fitting.= By F.C. ALLSOP. Tenth edition, 186
illus. including 8 folding plates, 185 pp. crown 8vo. (_1903_)
3 6
=Telephones:= their Construction and Fitting. By F.C. ALLSOP. Eighth
edition, 184 illus. 222 pp. crown 8vo. (_1909_)
3 6
=Thermo-electric Reactions= and Currents between Metals in Fused
Salts. By T. ANDREWS. 8vo, sewed. (_1896_)
1 0
=Auto-Transformer Design.= By A.H. AVERY. 25 illus. 60 pp. 8vo.
(_1909_)
_net_ 3 6
=Principles of Electric Power= (Continuous Current) for Mechanical
Engineers. By A.H. BATE. 63 illus. 204 pp. crown 8vo. (_1905_)
(FINSBURY TECHNICAL MANUAL)
_net_ 4 6
=Practical Construction of Electric Tramways.= By WILLIAM R. BOWKER.
93 illus. 119 pp. 8vo. (_1903_)
_net_ 6 0
=Design and Construction of Induction Coils.= By A.F. COLLINS. 155
illus. 272 pp. demy 8vo. (_New York, 1909_)
_net_ 12 6
=Switchboard Measuring Instruments= for Continuous and Polyphase
Currents. By J.C. CONNAN. 117 illus. 150 pp. 8vo, cloth. (_1908_)
_net_ 5 0
=Electric Cables, their Construction and Cost.= By D. COYLE and F.J.
O. HOWE. With many diagrams and 216 tables, 467 pp. crown 8vo,
leather. (_1909_)
_net_ 15 0
=Management of Electrical Machinery.= By F.B. CROCKER and S.S.
WHEELER. Eighth edition, 131 illus. 223 pp. crown 8vo. (_New York,
1909_)
_net_ 4 6
=Electric Lighting:= A Practical Exposition of the Art. By F.B.
CROCKER. Royal 8vo. (_New York._)
Vol. I. =The Generating Plant.= Sixth edition, 213 illus. 470
pp. (_1904_)
_net_ 12 6
Vol. II. =Distributing Systems and Lamps.= Second edition, 391
illus. 505 pp. (_1905_)
_net_ 12 6
=The Care and Management of Ignition Accumulators.= By H.H.U. CROSS.
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=Dynamo Electric Machinery.= By Prof. S.P. THOMPSON. Seventh edition,
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=Treatise on the Richards Steam Engine Indicator.= By C.T.
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=Practical Treatise on the Steam Engine.= By A. RIGG. Second
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=Slide and Piston Valve Geared Steam Engines.= By W.H. UHLAND.
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=How to run Engines and Boilers.= By E.P. WATSON. Fifth
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=Practical Method of Designing Slide Valve Gearing.= By E.J.
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=Brassfounders' Alloys.= By J.F. BUCHANAN. Illustrated, 129 pp.
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=Practical Notes on Pipe Founding.= By J.W. MACFARLANE. 15
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=Roll Turning for Sections in Steel and Iron.= By A. SPENCER.
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=Manual of Assaying Gold, Silver, Copper and Lead Ores.= By
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=Hydraulic Gold Miners' Manual.= By T.S.G. KIRKPATRICK. Second
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=Tests for Ores, Minerals and Metals of Commercial Value.= By
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=Theory and Practice of Centrifugal Ventilating Machines.= By
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=The Colourist.= A method of determining colour harmony. By
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=Engineering Thermodynamics.= By C.F. HIRSCHFELD. 22 illus. 157
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=Reform in Chemical and Physical Calculations.= By C.J.T.
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=Introduction to the Study of Colour Phenomena.= By J.W.
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=Simple and Automatic Vacuum Brakes.= By C. BRIGGS, G.N.R. 11
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Transcriber's Notes
Obvious punctuation and spelling errors and inconsistent hyphenation
have been corrected.
Italic text is denoted by _underscores_ and bold text by =equal signs=.
The OE ligature has been replaced by the separate characters.
The fractions ¼, ½ and ¾ are represented using the Latin-1 characters,
but other fractions use the / and - symbols, e.g. 3/8 or 2-5/8.
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other exponents are indicated by the caret character, for example,
v^{1·85}
Subscripts are simply enclosed in braces, e.g. W{0}.
Other symbols that cannot be represented have been replaced by words
in braces: {alpha}, {pi}, {therefore}, {square root} and
{proportional to}.
The skin friction formulæ given on pages 11 and 128 have been corrected
by comparison with other sources. Respectively, the formulæ were
originally printed as
_f_ = 0·00000778_l_^{9·3}_v_^{1·85}
and
_f_ = 0·00000778_l_ - ^{00·7}_v_^{1·85}
In ambiguous cases, the text has been left as it appears in the
original book. | 82,299 | common-pile/project_gutenberg_filtered | 41135 | project gutenberg | project_gutenberg-dolma-0006.json.gz:2363 | https://www.gutenberg.org/ebooks/41135.txt.utf-8 |
uDGYSD11ax95FfJE | 4.4: Use of Determinants in Vector Calculus | 4.4: Use of Determinants in Vector Calculus
Consider two vectors \(\mathbf{u}=u_{1} \mathbf{i}+u_{2} \mathbf{j}+u_{3} \mathbf{j}\) and \(\mathbf{v}=v_{1} \mathbf{i}+v_{2} \mathbf{j}+v_{3} \mathbf{j}\) , written as you would find them in Calculus rather than as column matrices in Linear Algebra. The dot product of the two vectors is defined in Calculus as
\[\mathbf{u} \cdot \mathbf{v}=u_{1} v_{1}+u_{2} v_{2}+u_{3} v_{3}, \nonumber \]
and the cross product is defined as
\[\mathbf{u} \times \mathbf{v}=\left|\begin{array}{ccc} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ u_{1} & u_{2} & u_{3} \\ v_{1} & v_{2} & v_{3} \end{array}\right|=\mathbf{i}\left(u_{2} v_{3}-u_{3} v_{2}\right)-\mathbf{j}\left(u_{1} v_{3}-u_{3} v_{1}\right)+\mathbf{k}\left(u_{1} v_{2}-u_{2} v_{1}\right) \nonumber \]
where the determinant from Linear Algebra is used as a mnemonic to remember the definition. If the angle between the two vectors is given by \(\theta\) , then trigonometry can be used to show that
\[\mathbf{u} \cdot \mathbf{v}=|\mathbf{u}||\mathbf{v}| \cos \theta, \quad|\mathbf{u} \times \mathbf{v}|=|\mathbf{u}||\mathbf{v}| \sin \theta \nonumber \]
Now, if \(\mathbf{u}\) and \(\mathbf{v}\) lie in the \(x-y\) plane, then the area of the parallelogram formed from these two vectors, determined from base times height, is given by
\[\begin{aligned} A &=|\mathbf{u} \times \mathbf{v}| \\ &=\left|u_{1} v_{2}-u_{2} v_{1}\right| \\ &=\left|\operatorname{det}\left(\begin{array}{cc} u_{1} & u_{2} \\ v_{1} & v_{2} \end{array}\right)\right| . \end{aligned} \nonumber \]
This result also generalizes to three dimensions. The volume of a parallelopiped formed by the three vectors \(\mathbf{u}, \mathbf{v}\) , and \(\mathbf{w}\) is given by
\[\begin{aligned} V &=|\mathbf{u} \cdot(\mathbf{v} \times \mathbf{w})| \\ &=\left|\operatorname{det}\left(\begin{array}{ccc} u_{1} & u_{2} & u_{3} \\ v_{1} & v_{2} & v_{3} \\ w_{1} & w_{2} & w_{3} \end{array}\right)\right| . \end{aligned} \nonumber \]
An important application of this result is the change-of-variable formula for multidimensional integration. Consider the double integral
\[I=\iint_{A} \ldots d x d y \nonumber \]
over some unspecified function of \(x\) and \(y\) and over some designated area \(A\) in the \(x-y\) plane. Suppose we make a linear transformation from the \(x-y\) coordinate system to some \(u-v\) coordinate system. That is, let
\[u=a x+b y, \quad v=c x+d y, \nonumber \]
or in matrix notation,
\[\left(\begin{array}{l} u \\ v \end{array}\right)=\left(\begin{array}{ll} a & b \\ c & d \end{array}\right)\left(\begin{array}{l} x \\ y \end{array}\right) . \nonumber \]
Observe that the orthonormal basis vectors \(\mathbf{i}\) and \(\mathbf{j}\) transform into the vectors \(a \mathbf{i}+\) \(c \mathbf{j}\) and \(b \mathbf{i}+d \mathbf{j}\) so that a rectangle in the \(x-y\) coordinate system transforms into a parallelogram in the \(u-v\) coordinate system. The area \(A\) of the parallelogram in the \(u-v\) coordinate system is given by
\[A=\left|\operatorname{det}\left(\begin{array}{ll} a & c \\ b & d \end{array}\right)\right|=\left|\operatorname{det}\left(\begin{array}{ll} a & b \\ c & d \end{array}\right)\right| . \nonumber \]
Notice that because this was a linear transformation, we could have also written the area as
\[A=\left|\operatorname{det}\left(\begin{array}{ll} \frac{\partial u}{\partial x} & \frac{\partial u}{\partial y} \\ \frac{\partial v}{\partial x} & \frac{\partial v}{\partial y} \end{array}\right)\right| \nonumber \]
which is called the Jacobian determinant, or just the Jacobian. This result also applies to infinitesimal areas where a linear approximation can be made, and with
\[u=u(x, y), \quad v=v(x, y), \nonumber \]
the change of variables formula becomes
\[d u d v=\left|\operatorname{det} \frac{\partial(u, v)}{\partial(x, y)}\right| d x d y \nonumber \]
where in general, the Jacobian matrix is defined as
\[\frac{\partial(u, v)}{\partial(x, y)}=\left(\begin{array}{ll} \frac{\partial u}{\partial x} & \frac{\partial u}{\partial y} \\ \frac{\partial v}{\partial x} & \frac{\partial v}{\partial y} \end{array}\right) \nonumber \]
Note that sometimes we define the change of coordinates as
\[x=x(u, v), \quad y=y(u, v), \nonumber \]
and the change of variables formula will be
\[d x d y=\left|\operatorname{det} \frac{\partial(x, y)}{\partial(u, v)}\right| d u d v \nonumber \]
We can give two very important examples. The first in two dimensions is the change of variables from rectangular to polar coordinates. We have
\[x=r \cos \theta, \quad y=r \sin \theta, \nonumber \]
and the Jacobian of the transformation is
\[\left|\operatorname{det} \frac{\partial(x, y)}{\partial(r, \theta)}\right|=\left|\begin{array}{rr} \cos \theta & -r \sin \theta \\ \sin \theta & r \cos \theta \end{array}\right|=r . \nonumber \]
So to find the area of a circle of radius \(R\) , with formula \(x^{2}+y^{2}=R^{2}\) , we have
\[\int_{-R}^{R} \int_{-\sqrt{R^{2}-y^{2}}}^{\sqrt{R^{2}-y^{2}}} d x d y=\int_{0}^{2 \pi} \int_{0}^{R} r d r d \theta=\pi R^{2} . \nonumber \]
The second example in three dimensions is from cartesian to spherical coordinates. Here,
\[x=r \sin \theta \cos \phi, \quad y=r \sin \theta \sin \phi, \quad z=r \cos \theta \nonumber \]
The Jacobian is
\[\left|\operatorname{det} \frac{\partial(x, y, z)}{\partial(r, \theta, \phi)}\right|=\left|\begin{array}{ccc} \sin \theta \cos \phi & r \cos \theta \cos \phi & -r \sin \theta \sin \phi \\ \sin \theta \sin \phi & r \cos \theta \sin \phi & r \sin \theta \cos \phi \\ \cos \theta & -r \sin \theta & 0 \end{array}\right|=r^{2} \sin \theta . \nonumber \]
So to find the area of a sphere of radius \(R\) , with formula \(x^{2}+y^{2}+z^{2}=R^{2}\) , we have
\[\int_{-R}^{R} \int_{-\sqrt{R^{2}-z^{2}}}^{\sqrt{R^{2}-z^{2}}} \int_{-\sqrt{R^{2}-y^{2}-z^{2}}}^{\sqrt{R^{2}-y^{2}-z^{2}}} d x d y d z=\int_{0}^{2 \pi} \int_{0}^{\pi} \int_{0}^{R} r^{2} \sin \theta d r d \theta d \phi=\frac{4}{3} \pi R^{3} \nonumber \] | 1,033 | common-pile/libretexts_filtered | https://math.libretexts.org/Bookshelves/Differential_Equations/Applied_Linear_Algebra_and_Differential_Equations_(Chasnov)/02%3A_II._Linear_Algebra/04%3A_Determinants/4.04%3A_Use_of_Determinants_in_Vector_Calculus | libretexts | libretexts-0000.json.gz:43069 | https://math.libretexts.org/Bookshelves/Differential_Equations/Applied_Linear_Algebra_and_Differential_Equations_(Chasnov)/02%3A_II._Linear_Algebra/04%3A_Determinants/4.04%3A_Use_of_Determinants_in_Vector_Calculus |
7BglZceExCF6j6nN | Post-Secondary Peer Support Training Curriculum | What is Peer Support?
“Peer support is a system of giving and receiving help founded on key principles of respect, shared responsibility, and mutual agreement of what is helpful. Peer support is not based on psychiatric models and diagnostic criteria. It is about understanding another’s situation empathically through the shared experience of emotional and psychological pain.”
~Mead, Hilton, & Curtis (2001)
Peer support is a supportive relationship grounded in the principles of mutuality, empathy, and connection. Peer support harnesses the personal lived experience of a difficult life situation to create a mutually supportive relationship.
Peer support is a paradigm shift away from a clinical focus. It is grounded in connection and takes a horizontal approach to support.
Peer support is about making sense of one’s own pain, and channeling that experience empathically to walk alongside, acknowledge, connect with, and support someone else who also understands the pain of a mental health, substance use, and/or trauma issue.
Peer support services are diverse and adaptable to serve many demographics. However, there are commonalities in all types of peer support service delivery. Peer support services are:
- Always voluntary & self-directed
- Based on a shared lived experience
- Rooted in hope
- Relationship based (not clinical)
- Recovery focused
- Grounded in the action of moving toward wholeness, rather than away from illness
- Different from peer-delivered services, which are services delivered by someone with lived experience but not necessarily rooted in relationship-based connections, which is essential to peer support.
The Mental Health Commission of Canada, and the BC Healthy Minds Healthy Campuses document A Guide to Peer Support Programs on Post-Secondary Campuses defines peer support this way:
Peer support involves at least two individuals with a shared or similar experience, engaging in a relationship for the development and growth of both parties. Two defining factors of peer support are an independence from societal stigma and professional authorities. Most peer support groups address societal stigma by sharing personal stories that validate an individual’s experience as normal or understandable. Often these groups are formed around a specific issue or shared challenge, such as marginalization based on race or sexual orientation. These groups tend to focus on interacting with and improving the social structure that oppresses them.
Regardless of the identity of its members, peer support groups almost always focus on anti-labelling and the empowerment of marginalized persons. Peer support is similar to other forms of support, such as self-help, professional consultation, and social networks, but differs in that it offers members of a community the opportunity to connect with others who have similar experiences and learn from them directly. | 566 | common-pile/pressbooks_filtered | https://opentextbc.ca/peersupport/chapter/what-is-peer-support/ | pressbooks | pressbooks-0000.json.gz:53663 | https://opentextbc.ca/peersupport/chapter/what-is-peer-support/ |
pG_SH998Y5Emx9Ok | Principles of Management | 46 Planning and Executing Change Effectively
Learning Objectives
- Describe Lewin’s three-stage model of planned change.
- Describe how organizations may embrace continuous change.
How do you plan, organize, and execute change effectively? Some types of change, such as mergers, often come with job losses. In these situations, it is important to remain fair and ethical while laying off otherwise exceptional employees. Once change has occurred, it is vital to take any steps necessary to reinforce the new system. Employees can often require continued support well after an organizational change.
One of the most useful frameworks in this area is the three-stage model of planned change developed in the 1950s by psychologist Kurt Lewin. This model assumes that change will encounter resistance. Therefore, executing change without prior preparation is likely to lead to failure. Instead, organizations should start with unfreezing, or making sure that organizational members are ready for and receptive to change. This is followed by change, or executing the planned changes. Finally, refreezing involves ensuring that change becomes permanent and the new habits, rules, or procedures become the norm.
Unfreezing Before Change
Many change efforts fail because people are insufficiently prepared for change. When employees are not prepared, they are more likely to resist the change effort and less likely to function effectively under the new system. What can organizations do before change to prepare employees? There are a number of things that are important at this stage.
Communicating a Plan for Change
Do people know what the change entails, or are they hearing about the planned changes through the grapevine or office gossip? When employees know what is going to happen, when, and why, they may feel more comfortable. Research shows that those who have more complete information about upcoming changes are more committed to a change effort. Moreover, in successful change efforts, the leader not only communicates a plan but also an overall vision for the change. When this vision is exciting and paints a picture of a future that employees would be proud to be a part of, people are likely to be more committed to change.
Ensuring that top management communicates with employees about the upcoming changes also has symbolic value. When top management and the company CEO discuss the importance of the changes in meetings, employees are provided with a reason to trust that this change is a strategic initiative. For example, while changing the employee performance appraisal system, the CEO of Kimberly Clark made sure to mention the new system in all meetings with employees, indicating that the change was supported by the CEO.
Develop a Sense of Urgency
People are more likely to accept change if they feel that there is a need for it. If employees feel their company is doing well, the perceived need for change will be smaller. Those who plan the change will need to make the case that there is an external or internal threat to the organization’s competitiveness, reputation, or sometimes even its survival and that failure to act will have undesirable consequences. For example, Lou Gerstner, the former CEO of IBM, executed a successful transformation of the company in the early 1990s. In his biography Elephants Can Dance, Gerstner highlights how he achieved cooperation as follows: “Our greatest ally in shaking loose the past was IBM’s eminent collapse. Rather than go with the usual impulse to put on a happy face, I decided to keep the crisis front and center. I didn’t want to lose the sense of urgency.”
Building a Coalition
To convince people that change is needed, the change leader does not necessarily have to convince every person individually. In fact, people’s opinions toward change are affected by opinion leaders or those people who have a strong influence over the behaviors and attitudes of others. Instead of trying to get everyone on board at the same time, it may be more useful to convince and prepare the opinion leaders. Understanding one’s own social networks as well as the networks of others in the organization can help managers identify opinion leaders. Once these individuals agree that the proposed change is needed and will be useful, they will become helpful allies in ensuring that the rest of the organization is ready for change. For example, when Paul Pressler became the CEO of Gap Inc. in 2002, he initiated a culture change effort in the hope of creating a sense of identity among the company’s many brands such as Banana Republic, Old Navy, and Gap. For this purpose, employees were segmented instead of trying to reach out to all employees at the same time. Gap Inc. started by training the 2,000 senior managers in “leadership summits,” who in turn were instrumental in ensuring the cooperation of the remaining 150,000 employees of the company.
Provide Support
Employees should feel that their needs are not ignored. Therefore, management may prepare employees for change by providing emotional and instrumental support. Emotional support may be in the form of frequently discussing the changes, encouraging employees to voice their concerns, and simply expressing confidence in employees’ ability to perform effectively under the new system. Instrumental support may be in the form of providing a training program to employees so that they know how to function under the new system. Effective leadership and motivation skills can assist managers to provide support to employees.
Allow Employees to Participate
Studies show that employees who participate in planning change efforts tend to have more positive opinions about the change. Why? They will have the opportunity to voice their concerns. They can shape the change effort so that their concerns are addressed. They will be more knowledgeable about the reasons for change, alternatives to the proposed changes, and why the chosen alternative was better than the others. Finally, they will feel a sense of ownership of the planned change and are more likely to be on board. Participation may be more useful if it starts at earlier stages, preferably while the problem is still being diagnosed. For example, assume that a company suspects there are problems with manufacturing quality. One way of convincing employees that there is a problem that needs to be solved would be to ask them to take customer calls about the product quality. Once employees experience the problem firsthand, they will be more motivated to solve the problem.
Executing Change
The second stage of Lewin’s three-stage change model is executing change. At this stage, the organization implements the planned changes on technology, structure, culture, or procedures. The specifics of how change should be executed will depend on the type of change. However, there are three tips that may facilitate the success of a change effort.
Continue to Provide Support
As the change is under way, employees may experience high amounts of stress. They may make mistakes more often or experience uncertainty about their new responsibilities or job descriptions. Management has an important role in helping employees cope with this stress by displaying support, patience, and continuing to provide support to employees even after the change is complete.
Create Small Wins
During a change effort, if the organization can create a history of small wins, change acceptance will be more likely. If the change is large in scope and the payoff is a long time away, employees may not realize change is occurring during the transformation period. However, if people see changes, improvements, and successes along the way, they will be inspired and motivated to continue the change effort. For this reason, breaking up the proposed change into phases may be a good idea because it creates smaller targets. Small wins are also important for planners of change to make the point that their idea is on the right track. Early success gives change planners more credibility while early failures may be a setback.
Eliminate Obstacles
When the change effort is in place, many obstacles may crop up along the way. There may be key people who publicly support the change effort while silently undermining the planned changes. There may be obstacles rooted in a company’s structure, existing processes, or culture. It is the management’s job to identify, understand, and remove these obstacles. Ideally, these obstacles would have been eliminated before implementing the change, but sometimes unexpected roadblocks emerge as change is under way.
Refreezing
After the change is implemented, the long-term success of a change effort depends on the extent to which the change becomes part of the company’s culture. If the change has been successful, the revised ways of thinking, behaving, and performing should become routine. To evaluate and reinforce (“refreeze”) the change, there are a number of things management can do.
Publicize Success
To make change permanent, the organization may benefit from sharing the results of the change effort with employees. What was gained from the implemented changes? How much money did the company save? How much did the company’s reputation improve? What was the reduction in accidents after new procedures were put in place? Sharing concrete results with employees increases their confidence that the implemented change was a right decision.
Reward Change Adoption
To ensure that change becomes permanent, organizations may benefit from rewarding those who embrace the change effort (an aspect of the controlling function). The rewards do not necessarily have to be financial. The simple act of recognizing those who are giving support to the change effort in front of their peers may encourage others to get on board. When the new behaviors employees are expected to demonstrate (such as using a new computer program, filling out a new form, or simply greeting customers once they enter the store) are made part of an organization’s reward system, those behaviors are more likely to be taken seriously and repeated, making the change effort successful.
Embracing Continuous Change
While Lewin’s three-stage model offers many useful insights into the process of implementing change, it views each organizational change as an episode with a beginning, middle, and end. In contrast with this episodic change assumption, some management experts in the 1990s began to propose that change is—or ought to be—a continuous process.
The learning organization is an example of a company embracing continuous change. By setting up a dynamic feedback loop, learning can become a regular part of daily operations. If an employee implements a new method or technology that seems to be successful, a learning organization is in a good position to adopt it. By constantly being aware of how employee actions and outcomes affect others as well as overall company productivity, the inevitable small changes throughout organizations can be rapidly absorbed and tailored for daily operations. When an organization understands that change does indeed occur constantly, it will be in a better position to make use of good changes and intervene if a change seems detrimental.
Key Takeaway
Effective change effort can be conceptualized as a three-step process in which employees are first prepared for change, then change is implemented, and finally the new behavioral patterns become permanent. According to emerging contemporary views, it can also be seen as a continuous process that affirms the organic, ever-evolving nature of an organization. | 2,408 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/tc3management/chapter/planning-and-executing-change-effectively/ | pressbooks | pressbooks-0000.json.gz:85666 | https://library.achievingthedream.org/tc3management/chapter/planning-and-executing-change-effectively/ |
1f1izxmwYH86i0GG | 10.6: Selecting Copyright for Page (Meta-Tags) | 10.6: Selecting Copyright for Page (Meta-Tags)
Each page should be marked with a copyright. This can be selected via the "Licensing" meta-tag in the collapsible "Page setting" panel on each page (see below).
Selecting the appropriate license requires more discussion about the nature of the license.
Creative Commons Licensing
The Creative Commons licenses are the most ubiquitous licensing in OER and grant "baseline rights", such as the right to distribute the copyrighted work worldwide for non-commercial purposes, and without modification. The details of each of these licenses depend on the version, and comprises a selection out of four conditions shown below.
Other licensing is possible including the GNU General Public License (GNU GPL) and the GNU Free Documentation License (GNU FPL). These are less common licensing in OER.
CC Licensing
Creative commons licenses are built in the following way.
First use CC - to indicate that the material is covered by a Creative Commons copyright, then use one or more of the following to indicate further restrictions
CC- 0 means that the material is public domain and there are no conditions
BY means that the author much be acknowledged, if this is the only condition then the copyright would be CC-BY
SA means that if the work is shared the conditions must be the same as the original. One could have CC-SA. CC-BY-SA is a common license
NC meant that only non-commercial use of the work is permitted.
ND means thar no changes can be made in the material.
Cannot ARBITRARILY Mix and Match Content from Different Licensing
Rights in an adaptation can be expressed by a CC license that is compatible with the status or licensing of the original work or works on which the adaptation is based.
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Avoid adding any content into the Libretexts that has a ND license on it. These do not play well with the community remixing aspect of the LibreTexts project. There are a few texts with this annoying license on the platform, but not many. | 517 | common-pile/libretexts_filtered | https://chem.libretexts.org/Courses/Remixer_University/Construction_Guide_for_LibreTexts_2e/10%3A_Page_Settings/10.06%3A_Selecting_Copyright_for_Page_(Meta-Tags) | libretexts | libretexts-0000.json.gz:31862 | https://chem.libretexts.org/Courses/Remixer_University/Construction_Guide_for_LibreTexts_2e/10%3A_Page_Settings/10.06%3A_Selecting_Copyright_for_Page_(Meta-Tags) |
U1Ed6-BYeg3sslPT | Spatial Humanities and Digital Storytelling: Critical Historical Approaches | Required Readings and Links
Greer, Kirsten, Katie Hemsworth, Adam Csank, and Kirby Calvert. “Interdisciplinary Research on Past Environments Through the Lens of Historical-Critical Physical Geographies.” Historical Geography 46, no. 1 (2018): 32–47. https://doi.org/10.1353/hgo.2018.0024.
https://muse.jhu.edu/article/723747
Maddison-MacFadyen, Margôt, and Adam Csank. “Mary Prince, Enslavement, Cavendish, and Historic Timber.” Historical Geography 46 (2018): 79–102. https://doi.org/10.1353/hgo.2018.0026.
Hemsworth, Katie. “Finding Commonality in the Archives.” Network in Canadian History & Environment (NiCHE) blog, July 25, 2019. https://niche-canada.org/2019/07/25/finding-commonality-in-the-archives/.
Jee, Megan (Prescott). “Web-based HGIS for Storytelling of Environmental Histories and Connections Across the North Atlantic” Network in Canadian History & Environment (NiCHE) blog, March 1, 2021. https://niche-canada.org/2021/03/01/web-based-hgis-for-storytelling-of-environmental-histories-and-connections-across-the-north-atlantic/ | 128 | common-pile/pressbooks_filtered | https://ecampusontario.pressbooks.pub/spatialhumanities/chapter/required-readings-and-links-4/ | pressbooks | pressbooks-0000.json.gz:37048 | https://ecampusontario.pressbooks.pub/spatialhumanities/chapter/required-readings-and-links-4/ |
sixWR-HPLc1P-btP | General Psychology | Psychological Disorders
Bipolar Disorder
Learning Objectives
- Describe the symptoms and risk factors of bipolar disorder
A person with bipolar disorder (commonly known as manic depression) often experiences mood states that vacillate between depression and mania; that is, the person’s mood is said to alternate from one emotional extreme to the other (in contrast to unipolar, which indicates a persistently sad mood).
To be diagnosed with bipolar disorder, a person must have experienced a manic episode at least once in his life; although major depressive episodes are common in bipolar disorder, they are not required for a diagnosis (APA, 2013). According to the DSM-5, a manic episode is characterized as a “distinct period of abnormally and persistently elevated, expansive, or irritable mood and abnormally and persistently increased activity or energy lasting at least one week,” that lasts most of the time each day (APA, 2013, p. 124). During a manic episode, some experience a mood that is almost euphoric and become excessively talkative, sometimes spontaneously starting conversations with strangers; others become excessively irritable and complain or make hostile comments. The person may talk loudly and rapidly, exhibiting flight of ideas, abruptly switching from one topic to another. These individuals are easily distracted, which can make a conversation very difficult. They may exhibit grandiosity, in which they experience inflated but unjustified self-esteem and self-confidence. For example, they might quit a job in order to “strike it rich” in the stock market, despite lacking the knowledge, experience, and capital for such an endeavor. They may take on several tasks at the same time (e.g., several time-consuming projects at work) and yet show little, if any, need for sleep; some may go for days without sleep. Patients may also recklessly engage in pleasurable activities that could have harmful consequences, including spending sprees, reckless driving, making foolish investments, excessive gambling, or engaging in sexual encounters with strangers (APA, 2013).
During a manic episode, individuals usually feel as though they are not ill and do not need treatment. However, the reckless behaviors that often accompany these episodes—which can be antisocial, illegal, or physically threatening to others—may require involuntary hospitalization (APA, 2013). Some patients with bipolar disorder will experience a rapid-cycling subtype, which is characterized by at least four manic episodes (or some combination of at least four manic and major depressive episodes) within one year.
Watch It
Not sleeping for days on end. Long periods of euphoria. Racing thoughts. Grandiose ideas. Mania. Depression. All of these are symptoms of Bipolar Disorder. In the following episode of Crash Course Psychology, Hank talks about mood disorders and their causes as well as how these disorders can impact people’s lives.
Risk Factors for Bipolar Disorder
Bipolar disorder is considerably less frequent than major depressive disorder. In the United States, 1 out of every 167 people meets the criteria for bipolar disorder each year, and 1 out of 100 meet the criteria within their lifetime (Merikangas et al., 2011). The rates are higher in men than in women, and about half of those with this disorder report onset before the age of 25 (Merikangas et al., 2011). Around 90% of those with bipolar disorder have a comorbid disorder, most often an anxiety disorder or a substance abuse problem. Unfortunately, close to half of the people suffering from bipolar disorder do not receive treatment (Merikangas & Tohen, 2011). Suicide rates are extremely high among those with bipolar disorder: around 36% of individuals with this disorder attempt suicide at least once in their lifetime (Novick, Swartz, & Frank, 2010), and between 15%–19% complete suicide (Newman, 2004).
Licenses and Attributions (Click to expand)
CC licensed content, Original
- Modification and adaptation, addition of link to learning. Provided by: Lumen Learning. License: CC BY: Attribution
CC licensed content, Shared previously
- Mood Disorders. Authored by: OpenStax College. Located at: https://openstax.org/books/psychology-2e/pages/15-7-mood-disorders. License: CC BY: Attribution. License Terms: Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction
All rights reserved content
- Depressive and Bipolar Disorders: Crash Course Psychology #30. Authored by: Hank Green. Provided by: CrashCourse. Located at: https://www.youtube.com/watch?v=ZwMlHkWKDwM&feature=youtu.be&list=PL8dPuuaLjXtOPRKzVLY0jJY-uHOH9KVU6. License: Other. License Terms: Standard YouTube License
mood disorder characterized by mood states that vacillate between depression and mania
state of extreme elation and agitation
period in which an individual experiences mania, characterized by extremely cheerful and euphoric mood, excessive talkativeness, irritability, increased activity levels, and other symptoms
symptom of mania that involves an abruptly switching in conversation from one topic to another | 954 | common-pile/pressbooks_filtered | https://pressbooks.online.ucf.edu/lumenpsychology/chapter/mood-disorders/ | pressbooks | pressbooks-0000.json.gz:44676 | https://pressbooks.online.ucf.edu/lumenpsychology/chapter/mood-disorders/ |
gmE8_DsADuVAQ1YD | Description of a new sucker (Pantosteus Jordani) from the Upper Missouri Basin / by Barton W. Evermann. | Assistant, U. S. Fish Commission.
In the following paper is given a description of a new species of sucker, Pantos¬ teus jordani, together with a discussion of the distribution of the various species of the genus Pantosteus , it being thought advisable to publish this in advance of the completion of a report upon investigations in the Black Hills region upon which I am now engaged, and of which this is to be regarded as forming a part.
PANTOSTEUS JORDANI sp. nov.
Pantosteus virescens, Jordan, Bull. 4, vol. iv, U. S. Nat. Mus., 1878, 780 (Sweet Grass Hills, Montana). Catostomus discobolus, Evermann, Bull. U. S. Fish Comm. 1891, pi. xvm, fig. 1, 41 (Red Rock River, Red Rock, Mont., and Beaverhead River, Dillon, Mont.).
Body rather stout, subterete, back gently and regularly arched from snout to ori¬ gin of dorsal, thence nearly straight to base of caudal; head small, short, and conic, interorbital space broad and but little convex; snout long, about half length of head; mouth large, broad; lower lip broad, very little incised, covered with tubercles of moderate size; upper lip also broad, extending well down on sides of mouth, tubercles in about 3 or 4 rows ; cartilaginous sheath of lower lip well developed ; caud al peduncle stout, not much compressed; scales small and much crowded anteriorly, lateral line straight and near axis of body; dorsal small, its height 14 in head and a little greater than base of fin, its origin considerably nearer snout than base of caudal; pectorals long, about equal to length of head, reaching more than half way to the ventrals; ventrals short, not reaching vent; anal about 4 longer than pectorals, reaching base of caudal ; fbntanelle reduced to a very narrow slit, practically obliterated in the older individuals; peritoneum very black; air-bladder small, the posterior part long and very slender.
Color, dark-greenish above, scales covered very closely down to the paired fins with innumerable fine dark or greenish specks, most numerous on back; under parts pale; in life, or immediately upon putting in alcohol, some specimens were observed to have a broad orange band along the side, this probably being a marking present dur¬ ing the breeding season. Young specimens 2 to 3 inches long are frequently mottled very much like the young of Catostomus teres and C. nigricans .
In the report upon the explorations in Montana and Wyoming by Dr. O. P. Jenkins and myself, I hesitated to regard the specimens which we collected at Red Rock and Dillon as being new, and identified them as Gatostomus discobolus Cope.
The narrow fontauelle and the cartilaginous sheath of the lower lip, together with the uncertainty as to the exact locality from which Prof. Cope’s types came, seemed to favor this identification. Upon the suggestion of Dr. Jordan that the types of G. discobolus were probably the young of C. latipinnis and that my specimens were prob¬ ably an undescribed species, I was induced to make a reexamination of the question. This was particularly desirable in view of the fact that so much additional material had resulted from my recent explorations in the Black Hills.
Prof. Cope’s types of Gatostomu-i discobolus consisted of “two specimens, one certainly, the other probably, from the Green River, Wyoming,”* and can not now be found, but there are twelve specimens from the Colorado Basin in the National Muse¬ um under the name C. discobolus, presumably identified as such by Prof. Cope. These are quite certainly young specimens of Pantosteus delphinus, and I am inclined to the belief that the types of G. discobolus were also the young of this species rather than the young of C. latipinnis. Should this be the case, the species would stand as Pan¬ tosteus discobolus (Cope), discobolus having priority over delphinus.
While this question can not be definitely determined, Prof. Cope’s description of G. discobolus applying equally well to G. latipinnis and P. delphinus , the probabilities are strongly in favor of this view, and I therefore adopt the name discobolus instead of delphinus for the Pantosteus of the Colorado River.
As remarked elsewhere in this paper, all the other specimens in the Museum which have been called G. discobolus (and which are from Lapwai Creek, Idaho), are undoubt¬ edly young specimens of G. catostomus.
An examination of the air bladder in several species of suckers shows marked differences. In all species of Pantosteus examined (P. generosus, plebeius , discobolus and jordani) the air bladder is quite small, the first (anterior) compartment being quite short, while the second is very long and slender, usually to 3 times the length of the first.
In one specimen of P. discobolus the air bladder was large, but this specimen had been previously cut open and examined by some one; the air bladder was detached, and may possibly belong to another fish.
In all species of Gatostomus examined ( G . latipinnis , catostomus , ardens, and grisens), the air bladder is large, very much larger than in any Pantosteus and very differ¬ ent in appearance except in G. latipinnis , in which the air bladder greatly resembles that of Pantosteus.
Pantosteus jordani is rather intermediate in its structure between Pantosteus and Gatostomus , but, on the whole, its characters indicate a closer relationship with the species of the former genus, in which it should be placed if Pantosteus and Gatosto¬ mus are to be regarded as generically distinct, the propriety of which is doubtful. The high development of the cartilaginous sheath is a character possessed by all the species of Pantosteus and is not found among the species of Gatostomus , except in G. catostomus , where it is more pronounced than in any other species of that genus.
The entire obliteration of the fontauelle, even in the most typical species of Pan¬ tosteus , is a question of age, the fontanelle being more or less evident as a very narrow slit in the young of all the species of which the young are known.
Pantosteus jordani is, on the one hand, most closely related to Pantosteus virescens Cope and P. discobolus (Cope), while on the other it resembles G. catostomus (Forst.). It is the most abundant and most generally distributed species of the family in the streams flowing from the Black Hills, and frequents the clear, colder, and swifter parts of the streams. With the exception of Hat Creek, all the streams in which it has been found are clear and cold. We did not find it at all in the South Fork of the Cheyenne nor in the Loup or Beaver Creek at Ravenna. It is apparently a fish of small size which delights in the upper reaches and colder, clearer portions of the smaller mountain streams of the Upper Missouri basin.
In connection with my study of this species I was led to an examination of all the specimens of Pantosteus and the related species of Gatostomus to be found among the collections now in the U. S. National Museum. Dr. Jordan, in his Catalogue of Fishes of North America, published in 1885, recognized but three species of Pantosteus , viz, plebeius , generosus, and guzmaniensis , and expressed the opinion that Minomus bard us and M. delphinus of Cope should be considered identical with P. plebeius , and further, that P. virescens Cope is the same as Acomus guzmaniensis Girard.
BULLETIN OF THE UNITED STATES FISH COMMISSION.
The collections made in 1880 in Colorado and Utah by Dr. Jordan and myself contain numerous specimens of Pantosteus from the Rio Grande, Colorado, and Utah basins, the study of which led Dr. Jordan to admit the three species, P. plebeius , generosus , and delphinus . He at this time regarded Acomus guzmaniensis as identical with P. plebeius, and P. virescens as being probably the same as P. delpliinus.
These collections of 1889 suggested the strong probability of the limited distribution of each species of this genus, and that each is likely confined to a single hydrographic basin. My examination of the types of all the nominal species now to be found, and the comparison with them of all the other material obtainable, confirm this view. I can see no differences of any value among the specimens from the different places in the Rio Grande basin, and must regard them all as being identical with Baird and Girard’s Catostomus plebeius, the types of which came from the Rio Mimbres, a tribu¬ tary of Lake Guzman, which is in the Rio Grande basin. All the specimens from the Colorado basin are easily referable to P. delpliinus (Cope), while all those from the Utah basin are with equal certainty P. generosus (Girard).
The only specimen from the Arkansas basin is the type of Cope’s P. virescens, which is said to have been taken in the Arkansas River at Pueblo, Colo. This specimen is about 14 inches in total length, and is in good condition. It is most closely related to P. discobolus , and, like that species, has a slender caudal peduncle and very small scales, which I count as 17-103-10, and 45 before the dorsal. I am not sure that this is really distinct from P. discobolus , and doubt if the specimen came from the Arkansas River.
Pantosteus plebeius, Jordan & Gilbert, Synopsis, 122, 1883 (Lake Guzman); Jordan, Bull. U. S. F. C., ix, for 1889 (1891), 19 (Rio Conejos, Colo., and Rio Grande at Del Norte and Alamosa, Colo.). Catostomus ( Acomus ) guzmaniensis Grd., Proc. Acad. Nat. Sci. Phila. 1856, 173 (Janos River, tributary of Lake Guzman, Chihuahua).
y and Copeland, Check List, 1876, 156.
Panto8teu8 generosus, Jordan, Bull, xii, U. S. Nat. Mus., 1878, 183 (Great Basin of Utah); ibid., Jordan and Gilbert, Synopsis, 1883, 123 (only in part); ibid., Jordan, Cat. Fish. N. A., 1885, 17 ; ibid., Bull, ix, U. S. Fish Com. for 1889 (i891). 31 and 35 (Jordan River, Sevier River, and Utah Lake).
Pantosteus platyrhynchus, Cope & Yarrow, Zool. Wheeler Survey, 1875, 673, pi. xxix, figs. 3 and 3a (Provo River, Utah); ibid., Jordan & Copeland, Check List, 156, 1876; ibid., Bull, xii, U. S. Nat. Mus., 1878, 183 (Utah Lake and tributaries); ibid., Jordan & Gilbert, Synopsis, 1883, 123 (Utah Lake).
Pantosleus delphinus, Jordan & Gilbert, Synopsis, 1883, 122 (probably from Green River) ; ibid., Jordan, Bull, ix, U. S. Fish Comm, for 1889 (1891), 27 (Eagle River, Gypsum, Colo. ; Gunnison and Uncompahgre rivers, Delta, Colo.; Rio de las Animas and Rio Florida, Durango, Colo.). f Minornus bardus Cope, Hayden’s Geol. Survey of Wyo., 1870, 436 (probably Green River).
Catostomus discobolus Cope, Proc. Am. Philo. Soc. Phila. 1874, 138; ibid., Plagopterime and Ichtliyol. of Utah, 1874,10 (“ Zuni River, Arizona;” “Arizona”); ibid., Cope & Yarrow, Zool. Wheeler Survey, 1875, 677 (Zuni River, N. M. ; “Arizona”).
now be found in the IJ. S. National Museum, together with my identification of each.
All the specimens which have been called P. jarrovii that I have been able to find are apparently from the Rio Grande and Utah basins, those from the former being P. plebeius and those from the latter P. generosus.
found, but were most likely P. discobolus , which is known to occur there.
There are seven bottles of suckers in the Museum, labeled Catostomus discobolus. Three of these lots are from the Colorado Basin and are almost certainly young spec¬ imens of P. discobolus. They have been regarded by Dr. Jordan as the young of Catostomus latipinnis ; but I find, upon comparing them with small specimens of lati¬ pinnis from the Uncompahgre and Sevier rivers, that the foutanelle is more nearly obliterated, the lower lip is broader and less deeply incised, and the cartilaginous sheath much more developed than in latipinnis Furthermore, they are not distin¬ guishable by me from specimens of what has been called P. delphinus of the same size
the scales are equally small, and the fontauelle is as imperfect.
All the other specimens in the Museum labeled Catostomus discobolus were col¬ lected by Gapt. Bendire, in Lapwai Creek, Idaho, which is in the Snake River Basin, and are undoubtedly the young of Catostomus catostomus.
The specimens collected at Amarilla, 1ST. Mex., by Dr. Y arrow have the caudal peduncle a little deeper than in other specimens of discobolus with which I have com¬ pared them, but they are certainly not generosus ; they may possibly be plebeius , but are most likely discobolus.
According to this view, Prof. Cope’s types of P.jarrovii from the Rio Grande are plebeius, those from the Utah basin are generosus, and those (if any) from the Colo¬ rado basin are discobolus. All these specimens are small and some of them, partic¬ ularly those said to be from Zufii, are in such poor condition as to render certain identification impossible. It is x>ossible that the locality labels have been confused.
In P. discobolus the lower lip is somewhat broader and the tubercles smaller than in plebeius and generosus. It bears a close external resemblance to C. latipinnis , especially in the general shape of the body, the slender caudal peduncle, and the small, subequal scales, but the eye is smaller.
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2KQZ7Jx1fLMSSQmV | Fundamentals of Anatomy and Physiology | 15.2 Anatomy and Physiology of the Female Reproductive System
Learning Objectives
By the end of this section, you will be able to:
- Describe the structure and function of the organs of the female reproductive system
- List the steps of oogenesis
- Describe the hormonal changes that occur during the ovarian and menstrual cycles
- Trace the path of an oocyte from ovary to fertilisation
The female reproductive system functions to produce gametes and reproductive hormones, just like the male reproductive system; however, it also has the additional task of supporting the developing foetus and delivering it to the outside world. Unlike its male counterpart, the female reproductive system is located primarily inside the pelvic cavity (Figure 15.2.1). Recall that the ovaries are the female gonads. The gamete they produce is called an oocyte. We will discuss the production of oocytes in detail shortly. First, let us look at some of the structures of the female reproductive system.
External Female Genitals
The external female reproductive structures are referred to collectively as the vulva (Figure 15.2.2). The mons pubis is a pad of fat that is located at the anterior, over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of hair-covered skin that begin just posterior to the mons pubis. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) extend medial to the labia majora. Although they naturally vary in shape and size from woman to woman, the labia minora serve to protect the female urethra and the entrance to the female reproductive tract.
The superior, anterior portions of the labia minora come together to encircle the clitoris (or glans clitoris), an organ that originates from the same cells as the glans penis and has abundant nerves that make it important in sexual sensation and orgasm. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body, regardless of penile–vaginal intercourse. The vaginal opening is located between the opening of the urethra and the anus. It is flanked by outlets to the Bartholin’s glands (or greater vestibular glands).
Vagina
The vagina, shown at the bottom of Figure 15.2.1 and Figure 15.2.2, is a muscular canal (approximately 10 cm long) that serves as the entrance to the reproductive tract. It also serves as the exit from the uterus during menses and childbirth. The outer walls of the anterior and posterior vagina are formed into longitudinal columns, or ridges, and the superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer, fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina to accommodate intercourse and childbirth. The thin, perforated hymen can partially surround the opening to the vaginal orifice. The hymen can be ruptured with strenuous physical exercise, penile–vaginal intercourse, and childbirth. The Bartholin’s glands and the lesser vestibular glands (located near the clitoris) secrete mucus, which keeps the vestibular area moist.
The vagina is home to a normal population of microorganisms that help to protect against infection by pathogenic bacteria, yeast, or other organisms that can enter the vagina. In a healthy woman, the most predominant type of vaginal bacteria is from the genus Lactobacillus. This family of beneficial bacterial flora secretes lactic acid, and thus protects the vagina by maintaining an acidic pH (below 4.5). Potential pathogens are less likely to survive in these acidic conditions. Lactic acid, in combination with other vaginal secretions, makes the vagina a self-cleansing organ. However, douching—or washing out the vagina with fluid—can disrupt the normal balance of healthy microorganisms and increase a woman’s risk for infections and irritation. Indeed, many doctors recommend that women do not douche and that they allow the vagina to maintain its normal healthy population of protective microbiota.
Ovaries
The ovaries are the female gonads (see Figure 15.2.1). Paired ovals, they are each about 2 to 3 cm in length, about the size of an almond. The ovaries are located within the pelvic cavity and are supported by the mesovarium, an extension of the peritoneum that connects the ovaries to the broad ligament. Extending from the mesovarium itself is the suspensory ligament that contains the ovarian blood and lymph vessels. Finally, the ovary itself is attached to the uterus via the ovarian ligament.
The ovary comprises an outer covering of cuboidal epithelium called the ovarian surface epithelium that is superficial to a dense connective tissue covering called the tunica albuginea. Beneath the tunica albuginea is the cortex, or outer portion, of the organ. The cortex is composed of a tissue framework called the ovarian stroma that forms the bulk of the adult ovary. Oocytes develop within the outer layer of this stroma, each surrounded by supporting cells. This grouping of an oocyte and its supporting cells is called a follicle. The growth and development of ovarian follicles will be described shortly. Beneath the cortex lies the inner ovarian medulla, the site of blood vessels, lymph vessels and the nerves of the ovary. You will learn more about the overall anatomy of the female reproductive system at the end of this section.
The Ovarian Cycle
The ovarian cycle is a set of predictable changes in a female’s oocytes and ovarian follicles. During a woman’s reproductive years, it is a roughly 28-day cycle that can be correlated with, but is different from, the menstrual cycle (discussed shortly). The cycle includes two interrelated processes: oogenesis (the production of female gametes) and folliculogenesis (the growth and development of ovarian follicles).
Oogenesis
Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 15.2.3). Oogonia are formed during foetal development and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the foetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.
The initiation of ovulation—the release of an oocyte from the ovary—marks the transition from puberty into reproductive maturity for women. From then on, throughout a woman’s reproductive years, ovulation occurs approximately once every 28 days. Just prior to ovulation, a surge of luteinising hormone triggers the resumption of meiosis in a primary oocyte. This initiates the transition from primary to secondary oocyte. However, as you can see in Figure 15.2.3, this cell division does not result in two identical cells. Instead, the cytoplasm is divided unequally, and one daughter cell is much larger than the other. This larger cell, the secondary oocyte, eventually leaves the ovary during ovulation. The smaller cell, called the first polar body, may or may not complete meiosis and produce second polar bodies; in either case, it eventually disintegrates. Therefore, even though oogenesis produces up to four cells, only one survives.
How does the diploid secondary oocyte become an ovum—the haploid female gamete? Meiosis of a secondary oocyte is completed only if a sperm succeeds in penetrating its barriers. Meiosis II then resumes, producing one haploid ovum that, at the instant of fertilisation by a (haploid) sperm, becomes the first diploid cell of the new offspring (a zygote). Thus, the ovum can be thought of as a brief, transitional, haploid stage between the diploid oocyte and diploid zygote.
The larger amount of cytoplasm contained in the female gamete is used to supply the developing zygote with nutrients during the period between fertilisation and implantation into the uterus. Interestingly, sperm contribute only DNA at fertilisation —not cytoplasm. Therefore, the cytoplasm and all of the cytoplasmic organelles in the developing embryo are of maternal origin. This includes mitochondria, which contain their own DNA.
Everyday Connections
Mapping Human History with Mitochondrial DNA
When we talk about human DNA, we’re usually referring to nuclear DNA; that is, the DNA coiled into chromosomal bundles in the nucleus of our cells. We inherit half of our nuclear DNA from our father, and half from our mother. However, mitochondrial DNA (mtDNA) comes only from the mitochondria in the cytoplasm of the fat ovum we inherit from our mother. She received her mtDNA from her mother, who got it from her mother, and so on. Each of our cells contains approximately 1700 mitochondria, with each mitochondrion packed with mtDNA containing approximately 37 genes.
Mutations (changes) in mtDNA occur spontaneously in a somewhat organised pattern at regular intervals in human history. By analysing these mutational relationships, researchers have been able to determine that we can all trace our ancestry back to one woman who lived in Africa about 200,000 years ago. Scientists have given this woman the biblical name Eve, although she is not, of course, the first Homo sapien female. More precisely, she is our most recent common ancestor through matrilineal descent.
This does not mean that everyone’s mtDNA today looks exactly like that of our ancestral Eve. Because of the spontaneous mutations in mtDNA that have occurred over the centuries, researchers can map different “branches” off of the “main trunk” of our mtDNA family tree. Your mtDNA might have a pattern of mutations that aligns more closely with one branch, and your neighbour’s may align with another branch. Still, all branches eventually lead back to Eve.
But what happened to the mtDNA of all of the other Homo sapiens females who were living at the time of Eve? Researchers explain that, over the centuries, their female descendants died childless or with only male children and thus, their maternal line—and its mtDNA—ended.
Folliculogenesis
Again, ovarian follicles are oocytes and their supporting cells. They grow and develop in a process called folliculogenesis, which typically leads to ovulation of one follicle approximately every 28 days, along with death to multiple other follicles. The death of ovarian follicles is called atresia and can occur at any point during follicular development. Recall that, a female infant at birth will have one to two million oocytes within her ovarian follicles, and that this number declines throughout life until menopause, when no follicles remain. As you will see next, follicles progress from primordial, to primary, to secondary and tertiary stages prior to ovulation—with the oocyte inside the follicle remaining as a primary oocyte until right before ovulation.
Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 15.2.4). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte and they can stay in this resting state for years—some until right before menopause.
After puberty, a few primordial follicles will respond to a recruitment signal each day and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles—now called secondary follicles (see Figure 15.2.4)—increase in diameter, adding a new outer layer of connective tissue, blood vessels and theca cells—cells that work with the granulosa cells to produce oestrogens.
Within the growing secondary follicle, the primary oocyte now secretes a thin acellular membrane called the zona pellucida that will play a critical role in fertilisation. A thick fluid, called follicular fluid, that has formed between the granulosa cells also begins to collect into one large pool, or antrum. Follicles in which the antrum has become large and fully formed are considered tertiary follicles (or antral follicles). Several follicles reach the tertiary stage at the same time and most of these will undergo atresia. The one that does not die will continue to grow and develop until ovulation, when it will expel its secondary oocyte surrounded by several layers of granulosa cells from the ovary. Keep in mind that most follicles do not make it to this point. In fact, roughly 99 percent of the follicles in the ovary will undergo atresia, which can occur at any stage of folliculogenesis.
Hormonal Control of the Ovarian Cycle
The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH and FSH.
As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 15.2.5). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone oestradiol, a type of oestrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting oestrogen, is known as the follicular phase.
The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more oestrogen it will produce in response to LH stimulation. As a result of these large follicles producing substantial amounts of oestrogen, systemic plasma oestrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of oestrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically, only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.
When only the one dominant follicle remains in the ovary, it again begins to secrete oestrogen. It produces more oestrogen than all the developing follicles did together before the negative feedback occurred. It produces so much oestrogen that the normal negative feedback does not occur. Instead, these extremely high concentrations of systemic plasma oestrogen trigger a regulatory switch in the anterior pituitary that responds by secreting substantial amounts of LH and FSH into the bloodstream (see Figure 15.2.5). The positive feedback loop by which more oestrogen triggers release of more LH and FSH only occurs at this point in the cycle.
It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.
In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinisation (recall that the full name of LH is luteinising hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 15.2.4). Instead of oestrogen, the luteinised granulosa and theca cells of the corpus luteum begin to produce substantial amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH and FSH secretions low, so no new dominant follicles develop at this time.
The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a non-functional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete oestrogen.
The Uterine Tubes
The uterine tubes (also called fallopian tubes or oviducts) serve as the conduit of the oocyte from the ovary to the uterus (Figure 15.2.6). Each of the two uterine tubes is close to, but not directly connected to, the ovary and is divided into sections. The isthmus is the narrow medial end of each uterine tube that is connected to the uterus. The wide distal infundibulum flares out with slender, finger-like projections called fimbriae. The middle region of the tube, called the ampulla, is where fertilisation often occurs. The uterine tubes also have three layers: an outer serosa, a middle smooth muscle layer and an inner mucosal layer. In addition to its mucus-secreting cells, the inner mucosa contains ciliated cells that beat in the direction of the uterus, producing a current that will be critical to move the oocyte.
Following ovulation, the secondary oocyte surrounded by a few granulosa cells is released into the peritoneal cavity. The nearby uterine tube, either left or right, receives the oocyte. Unlike sperm, oocytes lack flagella, and therefore cannot move on their own. So how do they travel into the uterine tube and toward the uterus? High concentrations of oestrogen that occur around the time of ovulation induce contractions of the smooth muscle along the length of the uterine tube. These contractions occur every 4 to 8 seconds, and the result is a coordinated movement that sweeps the surface of the ovary and the pelvic cavity. Current flowing toward the uterus is generated by coordinated beating of the cilia that line the outside and lumen of the length of the uterine tube. These cilia beat more strongly in response to the high oestrogen concentrations that occur around the time of ovulation. As a result of these mechanisms, the oocyte–granulosa cell complex is pulled into the interior of the tube. Once inside, the muscular contractions and beating cilia move the oocyte slowly toward the uterus. When fertilisation does occur, sperm typically meet the egg while it is still moving through the ampulla.
If the oocyte is successfully fertilised, the resulting zygote will begin to divide into two cells, then four, and so on, as it makes its way through the uterine tube and into the uterus. There, it will implant and continue to grow. If the egg is not fertilised, it will simply degrade—either in the uterine tube or in the uterus, where it may be shed with the next menstrual period.
The open-ended structure of the uterine tubes can have significant health consequences if bacteria or other infectious agents enter through the vagina and move through the uterus, into the tubes, and then into the pelvic cavity. If this is left unchecked, an infection (typically bacterial) could quickly become life-threatening due to sepsis. The spread of an infection in this manner is of special concern when unskilled practitioners perform abortions in non-sterile conditions. Sepsis is also associated with sexually transmitted bacterial infections, especially gonorrhoea and chlamydia. These increase a woman’s risk for pelvic inflammatory disease (PID), infection of the uterine tubes or other reproductive organs. Even when resolved, PID can leave scar tissue in the tubes, leading to infertility.
The Uterus and Cervix
The uterus is the muscular organ that nourishes and supports the growing embryo (see Figure 15.2.6). Its average size is approximately 5 cm wide by 7 cm long (approximately 2 in by 3 in) when a female is not pregnant. It has three sections. The portion of the uterus superior to the opening of the uterine tubes is called the fundus. The middle section of the uterus is called the body (or corpus) of uterus . The cervix is the narrow inferior portion of the uterus that projects into the vagina. The cervix produces mucus secretions that become thin and stringy under the influence of high systemic plasma oestrogen concentrations and these secretions can facilitate sperm movement through the reproductive tract.
Several ligaments maintain the position of the uterus within the abdominopelvic cavity. The broad ligament is a fold of peritoneum that serves as a primary support for the uterus, extending laterally from both sides of the uterus and attaching it to the pelvic wall. The round ligament attaches to the uterus near the uterine tubes and extends to the labia majora. Finally, the uterosacral ligament stabilises the uterus posteriorly by its connection from the cervix to the pelvic wall.
The wall of the uterus is made up of three layers. The most superficial layer is the serous membrane, or perimetrium, which consists of epithelial tissue that covers the exterior portion of the uterus. The middle layer, or myometrium, is a thick layer of smooth muscle responsible for uterine contractions. Most of the uterus is myometrial tissue and the muscle fibres run horizontally, vertically and diagonally, allowing the powerful contractions that occur during labour and the less powerful contractions (or cramps) that help to expel menstrual blood during a woman’s period. Anteriorly directed myometrial contractions also occur near the time of ovulation and are thought to facilitate the transport of sperm through the female reproductive tract.
The innermost layer of the uterus is called the endometrium. The endometrium contains a connective tissue lining, the lamina propria, which is covered by epithelial tissue that lines the lumen. Structurally, the endometrium consists of two layers: the stratum basalis and the stratum functionalis (the basal and functional layers). The stratum basalis layer is part of the lamina propria and is adjacent to the myometrium; this layer does not shed during menses. In contrast, the thicker stratum functionalis layer contains the glandular portion of the lamina propria and the endothelial tissue that lines the uterine lumen. It is the stratum functionalis that grows and thickens in response to increased levels of oestrogen and progesterone. In the luteal phase of the menstrual cycle, special branches off the uterine artery called spiral arteries supply the thickened stratum functionalis. This inner functional layer provides the proper site of implantation for the fertilised egg, and—should fertilisation not occur—it is only the stratum functionalis layer of the endometrium that sheds during menstruation.
Recall that during the follicular phase of the ovarian cycle, the tertiary follicles are growing and secreting oestrogen. At the same time, the stratum functionalis of the endometrium is thickening to prepare for a potential implantation. The post-ovulatory increase in progesterone, which characterises the luteal phase, is key for maintaining a thick stratum functionalis. If a functional corpus luteum is present in the ovary, the endometrial lining is prepared for implantation. Indeed, if an embryo implants, signals are sent to the corpus luteum to continue secreting progesterone to maintain the endometrium, and thus maintain the pregnancy. If an embryo does not implant, no signal is sent to the corpus luteum and it degrades, ceasing progesterone production and ending the luteal phase. Without progesterone, the endometrium thins and, under the influence of prostaglandins, the spiral arteries of the endometrium constrict and rupture, preventing oxygenated blood from reaching the endometrial tissue. As a result, endometrial tissue dies and blood, pieces of the endometrial tissue, and white blood cells are shed through the vagina during menstruation, or the menses. The first menses after puberty, called menarche, can occur either before or after the first ovulation.
The Menstrual Cycle
Now that we have discussed the maturation of the cohort of tertiary follicles in the ovary, the build-up and then shedding of the endometrial lining in the uterus and the function of the uterine tubes and vagina, we can put everything together to talk about the three phases of the menstrual cycle—the series of changes in which the uterine lining is shed, rebuilds and prepares for implantation.
The timing of the menstrual cycle starts with the first day of menses, referred to as day one of a woman’s period. Cycle length is determined by counting the days between the onset of bleeding in two subsequent cycles. Because the average length of a woman’s menstrual cycle is 28 days, this is the time period used to identify the timing of events in the cycle. However, the length of the menstrual cycle varies among women and even in the same woman from one cycle to the next, typically from 21 to 32 days.
Just as the hormones produced by the granulosa and theca cells of the ovary “drive” the follicular and luteal phases of the ovarian cycle, they also control the three distinct phases of the menstrual cycle. These are the menses phase, the proliferative phase and the secretory phase.
Menses Phase
The menses phase of the menstrual cycle is the phase during which the lining is shed; that is, the days that the woman menstruates. Although it averages approximately five days, the menses phase can last from 2 to 7 days, or longer. As shown in Figure 15.2.7, the menses phase occurs during the early days of the follicular phase of the ovarian cycle, when progesterone, FSH and LH levels are low. Recall that progesterone concentrations decline because of the degradation of the corpus luteum, marking the end of the luteal phase. This decline in progesterone triggers the shedding of the stratum functionalis of the endometrium.
Proliferative Phase
Once menstrual flow ceases, the endometrium begins to proliferate again, marking the beginning of the proliferative phase of the menstrual cycle (see Figure 15.2.7). It occurs when the granulosa and theca cells of the tertiary follicles begin to produce increased amounts of oestrogen. These rising oestrogen concentrations stimulate the endometrial lining to rebuild.
Recall that the high oestrogen concentrations will eventually lead to a decrease in FSH because of negative feedback, resulting in atresia of all but one of the developing tertiary follicles. The switch to positive feedback—which occurs with the elevated oestrogen production from the dominant follicle—then stimulates the LH surge that will trigger ovulation. In a typical 28-day menstrual cycle, ovulation occurs on day 14. Ovulation marks the end of the proliferative phase as well as the end of the follicular phase.
Secretory Phase
In addition to prompting the LH surge, high oestrogen levels increase the uterine tube contractions that facilitate the pick-up and transfer of the ovulated oocyte. High oestrogen levels also slightly decrease the acidity of the vagina, making it more hospitable to sperm. In the ovary, the luteinisation of the granulosa cells of the collapsed follicle forms the progesterone-producing corpus luteum, marking the beginning of the luteal phase of the ovarian cycle. In the uterus, progesterone from the corpus luteum begins the secretory phase of the menstrual cycle, in which the endometrial lining prepares for implantation (see Figure 15.2.7). Over the next 10 to 12 days, the endometrial glands secrete a fluid rich in glycogen. If fertilisation has occurred, this fluid will nourish the ball of cells now developing from the zygote. At the same time, the spiral arteries develop to provide blood to the thickened stratum functionalis.
If no pregnancy occurs within approximately 10 to 12 days, the corpus luteum will degrade into the corpus albicans. Levels of both oestrogen and progesterone will fall, and the endometrium will grow thinner. Prostaglandins will be secreted that cause constriction of the spiral arteries, reducing oxygen supply. The endometrial tissue will die, resulting in menses—or the first day of the next cycle.
Disorders of the Female Reproductive System
Research over many years has confirmed that cervical cancer is most often caused by a sexually transmitted infection with human papillomavirus (HPV). There are over 100 related viruses in the HPV family, and the characteristics of each strain determine the outcome of the infection. In all cases, the virus enters body cells and uses its own genetic material to take over the host cell’s metabolic machinery and produce more virus particles.
HPV infections are common in both men and women. Indeed, a recent study determined that 42.5 percent of females had HPV at the time of testing. These women ranged in age from 14 to 59 years and differed in race, ethnicity and number of sexual partners. Of note, the prevalence of HPV infection was 53.8 percent among women aged 20 to 24 years, the age group with the highest infection rate.
HPV strains are classified as high or low risk according to their potential to cause cancer. Though most HPV infections do not cause disease, the disruption of normal cellular functions in the low-risk forms of HPV can cause the male or female human host to develop genital warts. Often, the body can clear an HPV infection by normal immune responses within 2 years. However, the more serious, high-risk infection by certain types of HPV can result in cancer of the cervix (Figure 15.2.8). Infection with either of the cancer-causing variants HPV 16 or HPV 18 has been linked to more than 70 percent of all cervical cancer diagnoses. Although even these high-risk HPV strains can be cleared from the body over time, infections persist in some individuals. If this happens, the HPV infection can influence the cells of the cervix to develop precancerous changes.
Risk factors for cervical cancer include having unprotected sex; having multiple sexual partners; a first sexual experience at a younger age, when the cells of the cervix are not fully mature; failure to receive the HPV vaccine; a compromised immune system; and smoking. The risk of developing cervical cancer is doubled with cigarette smoking.
When the high-risk types of HPV enter a cell, two viral proteins are used to neutralise proteins that the host cells use as checkpoints in the cell cycle. The best studied of these proteins is p53. In a normal cell, p53 detects DNA damage in the cell’s genome and either halts the progression of the cell cycle—allowing time for DNA repair to occur—or initiates apoptosis. Both processes prevent the accumulation of mutations in a cell’s genome. High-risk HPV can neutralise p53, keeping the cell in a state in which fast growth is possible and impairing apoptosis, allowing mutations to accumulate in the cellular DNA.
The prevalence of cervical cancer in Australia has dropped dramatically from approximately 1200 cases in 1994, down to approximately 700 cases in 2002. However, cervical cancer cases are steadily rising in Australia with 950 new cases in 2019.
Until 2017, the method of screening for cervical cancer in Australia was through a Pap test. Pap smears sample cells of the cervix, allowing the detection of abnormal cells. If pre-cancerous cells are detected, there are several highly effective techniques that are currently in use to remove them before they pose a danger. However, women in developing countries often do not have access to regular pap smears. As a result, these women account for as many as 80 percent of the cases of cervical cancer worldwide. In 2017, the Cervical Screening Test replaced the Pap test in Australia, which is estimated to protect an additional 30% of women. The cervical screening test is designed to find evidence of the human papillomavirus (HPV), rather than looking for abnormal cells as was done in the pap smear test.
In 2006, the first vaccine against the high-risk types of HPV was approved. There are now two vaccines available in Australia. Gardasil9 is designed to protect against nine of the HPV types that are responsible for 90% of cervical cancers in women and 95% of HPV-related cancers in men, and also against 90% of genital warts in both sexes. This vaccine is administered to females aged from nine to 45, and males aged 9 to 27. Cervarix® is given to females from as early as ten years of age, up to 45 years of age and is designed to prevent early-stage cervical cancers known as pre-cancerous lesions. A recent study suggests that the HPV vaccine has cut the rates of HPV infection by the four targeted strains at least in half. Unfortunately, the high cost of manufacturing the vaccine is currently limiting access to many people worldwide.
The Breasts
Whereas the breasts are located far from the other female reproductive organs, they are considered accessory organs of the female reproductive system. The function of the breasts is to supply milk to an infant in a process called lactation. The external features of the breast include a nipple surrounded by a pigmented areola (Figure 15.2.9), whose colouration may deepen during pregnancy. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterised by small, raised areolar glands that secrete lubricating fluid during lactation to protect the nipple from chafing. When a baby nurses, or draws milk from the breast, the entire areolar region is taken into the mouth.
Breast milk is produced by the mammary glands, which are modified sweat glands. The milk itself exits the breast through the nipple via 15 to 20 lactiferous ducts that open on the surface of the nipple. These lactiferous ducts each extend to a lactiferous sinus that connects to a glandular lobe within the breast itself that contains groups of milk-secreting cells in clusters called alveoli (see Figure 15.2.9). The clusters can change in size depending on the amount of milk in the alveolar lumen. Once milk is made in the alveoli, stimulated myoepithelial cells that surround the alveoli contract to push the milk to the lactiferous sinuses. From here, the baby can draw milk through the lactiferous ducts by suckling. The lobes themselves are surrounded by fat tissue, which determines the size of the breast; breast size differs between individuals and does not affect the amount of milk produced. Supporting the breasts are multiple bands of connective tissue called suspensory ligaments that connect the breast tissue to the dermis of the overlying skin.
During the normal hormonal fluctuations in the menstrual cycle, breast tissue responds to changing levels of oestrogen and progesterone, which can lead to swelling and breast tenderness in some individuals, especially during the secretory phase. If pregnancy occurs, the increase in hormones leads to further development of the mammary tissue and enlargement of the breasts.
Hormonal Birth Control
Birth control pills take advantage of the negative feedback system that regulates the ovarian and menstrual cycles to stop ovulation and prevent pregnancy. Typically, they work by providing a constant level of both oestrogen and progesterone, which negatively feeds back onto the hypothalamus and pituitary, thus preventing the release of FSH and LH. Without FSH, the follicles do not mature, and without the LH surge, ovulation does not occur. Although the oestrogen in birth control pills does stimulate some thickening of the endometrial wall, it is reduced compared with a normal cycle and is less likely to support implantation.
Some birth control pills contain 21 active pills containing hormones, and 7 inactive pills (placebos). The decline in hormones during the week that the woman takes the placebo pills triggers menses, although it is typically lighter than a normal menstrual flow because of the reduced endometrial thickening. Newer types of birth control pills have been developed that deliver low-dose oestrogens and progesterone for the entire cycle (these are meant to be taken 365 days a year), and menses never occurs. While some women prefer to have the proof of a lack of pregnancy that a monthly period provides, menstruation every 28 days is not required for health reasons and there are no reported adverse effects of not having a menstrual period in an otherwise healthy individual.
Because birth control pills function by providing constant oestrogen and progesterone levels and disrupting negative feedback, skipping even just one or two pills at certain points of the cycle (or even being several hours late taking the pill) can lead to an increase in FSH and LH and result in ovulation. It is important, therefore, that the woman follow the directions on the birth control pill package to successfully prevent pregnancy.
Ageing and the Female Reproductive System
Female fertility (the ability to conceive) peaks when women are in their twenties and is slowly reduced until a woman reaches 35 years of age. After that time, fertility declines more rapidly, until it ends completely at the end of menopause. Menopause is the cessation of the menstrual cycle that occurs because of the loss of ovarian follicles and the hormones that they produce. A woman is considered to have completed menopause if she has not menstruated in a full year. After that point, she is considered postmenopausal. The average age for this change is consistent worldwide at between 50 and 52 years of age, but it can normally occur in a woman’s forties, or later in her fifties. Poor health, including smoking, can lead to earlier loss of fertility and earlier menopause.
As a woman reaches the age of menopause, depletion of the number of viable follicles in the ovaries due to atresia affects the hormonal regulation of the menstrual cycle. During the years leading up to menopause, there is a decrease in the levels of the hormone inhibin, which normally participates in a negative feedback loop to the pituitary to control the production of FSH. The menopausal decrease in inhibin leads to an increase in FSH. The presence of FSH stimulates more follicles to grow and secrete oestrogen. Because small, secondary follicles also respond to increases in FSH levels, larger numbers of follicles are stimulated to grow; however, most undergo atresia and die. Eventually, this process leads to the depletion of all follicles in the ovaries, and the production of oestrogen falls off dramatically. It is primarily the lack of oestrogens that leads to the symptoms of menopause.
The earliest changes occur during the menopausal transition, often referred to as peri-menopause, when a women’s cycle becomes irregular but does not stop entirely. Although the levels of oestrogen are still the same as before the transition, the level of progesterone produced by the corpus luteum is reduced. This decline in progesterone can lead to abnormal growth, or hyperplasia, of the endometrium. This condition is a concern because it increases the risk of developing endometrial cancer. Two harmless conditions that can develop during the transition are uterine fibroids, which are benign masses of cells, and irregular bleeding. As oestrogen levels change, other symptoms that occur are hot flashes and night sweats, trouble sleeping, vaginal dryness, mood swings, difficulty focussing, and thinning of hair on the head along with the growth of more hair on the face. Depending on the individual, these symptoms can be entirely absent, moderate, or severe.
After menopause, lower amounts of oestrogens can lead to other changes. Cardiovascular disease becomes as prevalent in women as in men, possibly because oestrogens reduce the amount of cholesterol in the blood vessels. When oestrogen is lacking, many women find that they suddenly have problems with high cholesterol and the cardiovascular issues that accompany it. Osteoporosis is another problem because bone density decreases rapidly in the first years after menopause. The reduction in bone density leads to a higher incidence of fractures.
Menopausal Hormone Therapy (MHT)/Hormone replacement therapy (HRT), which employs medication (synthetic oestrogens and progestins) to increase oestrogen and progestin levels, can alleviate some of the symptoms of menopause. In 2002, the Women’s Health Initiative began a study to observe women for the long-term outcomes of hormone replacement therapy over 8.5 years. However, the study was prematurely terminated after 5.2 years because of evidence of a higher than normal risk of breast cancer in patients taking oestrogen-only HRT. The potential positive effects on cardiovascular disease were also not realised in the oestrogen-only patients. The results of other hormone replacement studies over the last 50 years, including a 2019 study of preclinical and clinical evidence, which found that use of oestrogen support the cardiovascular protective benefits of timely MHT. Additionally, the study showed that although MHT is correlated with a reduced risk of breast cancer development, its correlation with ovarian cancer is still unknown. Some researchers believe that the age group tested in the 2002 trial may have been too old to benefit from the therapy, thus skewing the results. In the meantime, intense debate and study of the benefits and risks of replacement therapy is ongoing. Current guidelines approve MHT for the reduction of hot flashes or flushes, but The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) recommends that each patient requires an individual assessment of risks and benefits prior to commencement of MHT.
Section Review
The external female genitalia are collectively called the vulva. The vagina is the pathway into and out of the uterus.
The ovaries produce oocytes, the female gametes, in a process called oogenesis. As with spermatogenesis, meiosis produces the haploid gamete (in this case, an ovum); however, it is completed only in an oocyte that has been penetrated by a sperm. In the ovary, an oocyte surrounded by supporting cells is called a follicle. In folliculogenesis, primordial follicles develop into primary, secondary and tertiary follicles. Early tertiary follicles with their fluid-filled antrum will be stimulated by an increase in FSH, a gonadotropin produced by the anterior pituitary, to grow in the 28-day ovarian cycle. Supporting granulosa and theca cells in the growing follicles produce oestrogens, until the concentration of oestrogen in the bloodstream is high enough that it triggers negative feedback at the hypothalamus and pituitary. This results in a reduction of FSH and LH, and most tertiary follicles in the ovary undergo atresia (they die). One follicle, usually the one with the most FSH receptors, survives this period and is now called the dominant follicle. The dominant follicle produces more oestrogen, triggering positive feedback and the LH surge that will induce ovulation. Following ovulation, the granulosa cells of the empty follicle luteinise and transform into the progesterone-producing corpus luteum. The ovulated oocyte with its surrounding granulosa cells is picked up by the infundibulum of the uterine tube and beating cilia help to transport it through the tube toward the uterus. Fertilisation occurs within the uterine tube and the final stage of meiosis is completed.
The uterus has three regions: the fundus, the body and the cervix. It has three layers: the outer perimetrium, the muscular myometrium and the inner endometrium. The endometrium responds to oestrogen released by the follicles during the menstrual cycle and grows thicker with an increase in blood vessels in preparation for pregnancy. If the egg is not fertilised, no signal is sent to extend the life of the corpus luteum, and it degrades, stopping progesterone production. This decline in progesterone results in the sloughing of the inner portion of the endometrium in a process called menses, or menstruation.
The breasts are accessory sexual organs that are utilised after the birth of a child to produce milk in a process called lactation. Birth control pills provide constant levels of oestrogen and progesterone to negatively feedback on the hypothalamus and pituitary, and suppress the release of FSH and LH, which inhibits ovulation and prevents pregnancy.
Review Questions
Critical Thinking Questions
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DGQBDKAXbGG_t5Jz | An illustrated system of bandaging : (selected from Goffres Précis de bandages) / by order of the Surgeon-General. | BANDAGES.
Bandages receive names from their composition ; they are termed simjyle when composed of one piece, and compoiuid when composed of one or more pieces, whether separate or sewed together. The diflferent pieces of a bandage may be simple, or split into a number of tails, or perforated ; some are both spAit and perforated. .
The mode of application, as well as their shape, also give names to bandages: such as the circular, the spjiral, the crossj the spica, the invafjinated , iha fgure of ei<jht, the T handayCj etc. The appropriateness of these names is sufficiently indicated in the descriptive application of each.
There is another system of bandaging, to which the French give the name of Linge Plein, executed with handkerchiefs, napkins, cravats, square pieces of linen, etc. These appliances do not, however, justify the enthusiasm of their patron, M. Mayor. They answer very well for slings, but their application cannot be made sufficiently uniform to serve the purposes of support afforded by the ordinary bandage.
Bandages are a kind of support, whose length and breadth ought to be proportioned to the parts to which they are applied, and they should never exceed twelve yards in length and three inches in breadth ; bandages longer or wider than this are difficult to roll, hard to maintain, and awkward to apply. Ordinary bandages are from one and a half to two
and a half inclies broad and tliree yards long. The ends of a bandage are called initial and termhial; their surfaces internal and external; and their borders mperior and inferior.
Bandages may be prepared with the tissues of hemp, flax, cotton, wool, and even caoutchouc The English prefer woollen bandages, which, according to them, compress without binding tightly, and adapt themselves, by their elasticity, to the different changes of volume which a part may undergo, keep up an equable and gentle warmth, and preserve, for a long time, the liquids of fomentation. But, despite these aclvantnges, they are little employed j their cost is too great; they become easily soiler' ; shrink when washed, and absorb with great facility putrid matters, of which it is very difficult to cleanse them.
The bandages most commonly employed are such as are made from lin^n or cotton. When they are not intended to come in contact with the parts, it matters but little whether they are made of linen or cotton; in the contrary case, linen should be preferred to cotton, which heats and irritates the delicate and susceptible skin.
Dr. Gariel, who has made in surgery such happy applications of vulcanized India-rubber, has proposed bandages made with this substance. Experience has taught us that their application is easy and uniform ; but their expansion by heat, their contraction by cold, the obstacle which they oppose to cutaneous transpiration, and, above all, the difficulty of regulating, in an adequate manner, the degree of constriction, force us to regard them as only calculated to fulfill some particular indications.
"Bandages," says Hippocrates, "should be light, supple, clean, without seams or eminences, strong, in order that they may stand traction, or even offer a little more resistance." It is also important that they should be cut by a straight thread ; without this, their edges ravel, become fringed, tangled, and they are difficult to apply. Unfortunately, it is not easy to obtain a straight thread ; therefore, it has been proposed, in place of it, to secure each edge of the bandage by a whipstitch. This, however, is difficult to effect ; for, if the stitch be at all tight, the edges of the bandage offer more resistance than its body, and then the bandage compresses in an unequal manner and produces often intolerable pain. To remedy this !neonTenienoe„ the Germans fabricate their bandages with a
loose, Hf2;lit, porous tissue, woven like Bilk ribbon ; that is to say, with a long horsehair in the edges, which is immediately withdrawn, and which leaves, instead of a selvage, a series of little curls, by the aid of whicb they stretch and take with great facility. These bandages appear to be exceedingly convenient; they were long ago recommended by Percy, who gave them the name of bnndes houclecs, and they have been eulogized by all authors who have devoted themselves to the subject of bandaging It would be desirable to have them adopted in all hospital establishments, where, despite the expense, bandages are so defective.
Sometimes bandages are not long enough and have to be pieced ; this operation should be performed with care. Two processes may be adopted : in the first, the two ends are laid one upon the other and sewed together face to face ; in the second, the two extremities are brought together and secured by a seam half an inch from their edges, each end being then turned back upon its respective bandage and sewed down. There is no preference for one or the otlier of these modes of joining a bandage ; both of them enable us to avoid ridges and inequalities, and are preferable to other 'met hod :i recommended by certain authors.
In order to be abje to make u.so of a bandage, it li indispensable to roll it, upon itself in such a manner as to give it, cither the form of a single cylinder, in the centre of which is found the terminal end, while the initial end is free, or in the form of two cylinders; in this way it is rolled by its two ends until they meet at a given point. In the first case, it is called a shujlc-hf'uded roller ; in the second, it is called a douhUhf'adrd roller.
It is not such an easy matter, as at first supposed, to roll a bandage well ; a good deal of pains ought, therefore, be taken to accustom one's-self to it. A bandage badly rolled yields and escapes from the fingers, and is very difficult to apply; when, on the contrary, it is well rolled, it can be held firmly, and applied with mote dexterity, promptitude and precision. To wind a bandage well, the terminal end must be seized and folded four or five times upon itself, in the form of a small roller, which is seized with the tliumb, the index and middle fingers of each hand, in such a way as to impress several turns of rotation upon itself; when it has acquired a cert'tia volume, its axis is placed between the pulp of the thumb, of
10 ON BANDA6IKG.
the second and third fingers of the left hand, while the portion not rolled is seized between the thumb and the radial border of the right index, in order to stretch and direct it. That done, the roller is made to rotate upon itself by the aid of the middle, ring and little fingers of the right hand, which are at the same time to maintain it in the palm of the same hand. When tbe roller has been made to execute a certain number of turns, and it is perceived not to be sufficiently tight, it must be held immovable between the fingers of the left hand, while the bandage is pulled with force by the right hand. If a single traction is not sufficient, it is repeated as often as necessary, and we thus succeed in giving to the bandage the firmness necessary for its proper application.
When the bandage is to be made into a double-headed roller, each one of its ends is rolled in the same manner alternately until they meet; ordinarily, more volume is given to one roller than the other, in order that one of the ends may be fixed and the bandage terminated with more regularity.
according as they are wound in one or two rollers.
To» apply regularly the single roller handage, the roller must be held between the extremity of the thumb and the index and middle fingers of the right hand (pi. 1 , A, fig. 1), unwind it lightly, while the initial end is held upon the point diametrically opposite the wound with the pulp of the thumb and index finger of the left hand (b, fig. 1 j ; it is fixed by two or three circular turns (2, 3, 4, fig. 2), and continued until the bandage is exhausted, when it is applied to a part entirely cylindrical ; when, on the contrary, it is applied to a conical part, such as the superior or inferior limbs, it is necessary, in order to avoid the fannelsj which would cause the bandage to lose all of its solidity, to have recourse to the circumvolutions known under the name of doloires, which are interrupted by what are called reverses. This is done by making obliquely with the aid of the left thumb (A, fig. 2), on the external face of the bandage, a fold upon itself, in such a way that the superior edge becomes inferior (5, 5, G, 6, 7, 7, 8, 8, 9, 9, fig. 2), and that it thus becomes appHed alternately upon the one and the other faces.
When the bandage is not intended to cover a long surface, you may, instead of securing the initial end, let it hang free five or six inches, and fix it thus by circular turns, avS in the
solidity.
When the bandage is entirely applied it may be secured, either by proceeding as we have just intimated, or by splitting the terminal end and tieing the two strips which result from this section, or by means of a needle and thread, or, lastly, which is the most usual, by means of pins. " They should always,'^ says M. Gerdy, ''be attached in such a manner that the convexity of the part does not make the point salient; that the latter, concealed in the thickness of the turns of the bandage, does not wound either the patient in the interval, or the surgeon at the moment of the dressing. Nor should the point of the pin be turned towards the end of the bandage, because, if the points of the pins were not solidly fixed by traversing alternately the end of the bandage and the circular turns which are below, they would ea^ly become detached.''
Whatever be the method resorted to, the last turn of the bandage must be fixed at a point diametrically opposite to the part injured : we thu.^ avoid the pain of inconvenient pressure; when the length of this turn is insufiicient for following this precept, it must be shortened by folding it back to a convenient distance.
The application of the double-roller handaf/c is much more difficult, and it requires a good deal of practice to succeed iu executing it skillfully. M. Gerdy being of all authors the one who has given the best precepts with regard to it, we will borrow from him the description of the following procedure, which he designates under the name of hitercros&huj hy reverse. We have endeavored to render it comprehensible in figure o, plate 1, and in the smaller figure 7, plate 2.
" Seize," says he, '•' the two rollers with both hands, apply the external face of the bandage over one of the points of circumference of the part to be covered by the bandage ; then unwind at the same time and in an equal manner the two rollers around this part (1, 1', pi. 1, fig. 3), until you have conducted them to a point opposite to that where you commenced the bandage ; there deviate obliquely one of the two rollers above or below ; continue, on the contrary, to carry the other and its band, following a horizontal line, until this band encounters that of the first, cover it and cross it by
forming witli it an acute angle; then return and reverse obliqiiely the first roller and the band deviated over the circular which covers it and crosses it (plate 2, minor figure 7) ; then make the two rollers follow their primitive direction ; bring them back a little above the point of departure, and recommence in front the same manoeuvre made behind (2, 2^ pi. 1, fig. 3) ; go on in this way to the end of the band (3, 3', 4, 4', pi. 1, fig. 3), and secure the last circumvolutions, as well as one of the ends, by horizontal circular -turns made with the most voluminous roller."
Besides the manual regulations which we have just traced, the application of bandages is subject to other precepts, the importance of which we cannot too strongly enforce. Thus the surgeon should place himself in snch a eouvenient attitude and in such a manner as not to have to move when passing the bandage around the patient. The latter should be placed in the most «onvenienfc position for sparing him pain, and in such a way that the wounded part may not be exposed to any jdstling or intemperate pressure. The bandage should be neither too loose nor too tight; in general, all those which are not employed with a view to compression, should only be light enough to insure necessary solidity. Unfortunately, it is far from being easy to hit the proper degree of constriction ; this precision can only be acquired by habit and long practice We are disposed to think we have obtained this point when the parts form above the circumvolutions a slight pro'nun once, soft, easily depressed, and not painful to the touch. When, on the contrary, the parts are the seat of violet- colored swelling, numbness and lively pain, it is an indication that the bandage is too tight; we must hasten then to- relax it, in order to avoid the development of gangrene. For tlie rest, tlie degree of constriction given to the bandage varies p.ccording to its humidity or dryness. With a view of obtaining in this respect fixed rules, A. Berard practised some experiments, of which the following is the result :
1st. Whether a bandage is applied dry or moistened, the pressure exercised by it augments with the number of turns that it describes; if, for example, Regnier's dynanometre, upon which it is wound, marks eleven degrees at the tenth turn, it will mark a little more at the fifteenth, a little more still at the twentieth.
2d. All things being otherwise equal, a moist bandage
presses more strongly than a dry one : thus, in many consecutive experiments, the game bandage has been seen, applied dry and moist, mark two or three more degrees in the f?econd case than in the first.
3d. A bandage, whether applied dry or wet, gradually relaxee in such a way that the pressure exercised by it diminishes from day to day; but, if it is wet, the pressure diminishes much more rapidly and completely, because this phenomenon depends at once upon its dei»iccation and relaxation : therefore, the pressure exercised by a dry bandage is less, but persists longer, and is more uniform : that obtained from a wet bandage is greater, more unequal, and less constant.
4th. When a dry bandage is applied and left in place for several days, the pros^sure descends several degrees : if the bandage is then moistened without being deranged, it tishtens rapidly and to such an extent, that the pressure exceeds the degree that it had attained at the moment of application ; but in proportion as the apparatus dries, the turns of the bandage relax, the pressure diminishes anew, talis lower than ever, and even ceases sometimes entirely.
Whatever be the purposes and the form of a bandage, the man of art should kno77 how to combine eJBicacy with dexterity and elegance. A bandage well applied inspires more confidence, re-assures the patient, persuades him that all possible care has been taken to insure his cure, and gives, at the same time, a good opinion of the surgeon. In that we should imitate A. Pare, and say, with him, ''after having applied a bandage, we should see that it has- been properly doiuj, that it is comely to the view, in order to content the patients and friends, for every one in his profession should embellish his work as far as possible."
BANDAGES FOR THE HEAD.
In general, all bandages of the head flatter and please the eye when they are well applied, but they are difficult, complicated, and it is only by the aid of frequent practice that we succeed in giving them proper regularity. The spherical form of the head and the presence of the hair favoring the slipping of the bandages, we are generally much disposed to apply them too tightly -, it is, however, very essential to avoid this excess, for they then become oppressive, occasion severe pain, and may often cause dangerous complications. The best means of succeeding is to first cover the head with a cap ; this simple precaution will enable us to give to the bandage sufiicient solidity without increasing the constriction. It should be employed in all bandaging for the head, and we beg the reader to remember this statement, in order to avoid the monotony of repeating it at each description.
and a half to two inches broad.
Application. — Cover the head with a cap and fix the initial end of the bandage over the forehead by two circular turns ; then descend little by little over the eyes, making four or five additional circles; mount again over the forehead, make a last turn, and fasten the bandage on one side of the head with a pin.
Uses. — This bandage is exceedingly simple. It is used to protect the eyes, to shade them from the contact of light, and to maintain topical applications in ophthalmia, lachrymal fistula, or after the operation for cataract.
Application. — If you wish to cover the right eye, place the initial end of the bandage above this eye, and make a circular horizontal turn from the forehead, passing above the eyebrows and the ears (1, 2). Having arrived at the nape, pass under the right ear and come towards the angle of the lower jaw ; from thence mount obliquely over the cheek, the internal angle of the eye, and the root of the nose; gain the left parietal protuberance (3), re-descend to the nape, and make a circular turn of the forehead,(4); returned to the nape, repeat a similar oblique and a similar circular turn (5, G), taking care not to cover the first turns of the bandage more than half way ; repeat the same manoeuvre two or three times (7, 8, 9), and terminate by circular turns around the head (10).
Uses. — They are the same as those of the preceding bandage. This variety for the eye is not very solid ; it requires to be watched and frequently re-applied It will be understood, of course, that if the bandage is intended to cover the left eye, it should be applied in an inverse sense.
Application. — If it is the right eye which is to be covered, leave hanging over the right side of the body of the lower jaw a pendant jet, about three-quarters of a yard in length ; then carry the bandage obliquely over the cheek, mounting towards the internal angle of the right eye, the root of the nose, the forehead, the left parietal protuberance (A, 1), and descend to the nape; from there come below the right ear, and fix, by a semi-circle of the neck (a, 2), the pendant (b, 1). Arrived at the nape, ascend obliquely above the right ear, make a horizontal circle of the forehead (a, 3) to fix there the; jet (a, 1). Keturned to the nape, pass below the right ear to make a second semi-circle of the neck (a, 4), iii order to
fix the jet (b, 2), that you have taken care to raise as far as the forehead, before the passage of the circular turn. From the nape return to the forehead, making a second horizontal circle (a, 5), which will fix the jet (b, 2). Reverse then this jet, in the form of an ear, over the circular (a, 5'), and direct it towards the neck to form the jet (b, 3). From the nape, make a third semi-circle of the neck (A, 6), which will fix the jet (b, 3). Elevate this jet, it will form then the jet (b, 4), destined to be carried upon the forehead, when a third circle of the forehead (a, 7) will have fixed the ear of the jets (b, 2, and B, 3). Then fix to the neck, by a fourth semicircle (a, 8), the ear formed by the jets (b, 3) and (e, 4), and return to the nape, to make from thence a fourth circle of the forehead (a, 9). Reverse upon this circle, in the form of an ear (b, 5), what remains of the tliiee-quarters of a yard forming the pendant jet, and floish by circular turns around the head with the roller (a, lU).
Uses. — This bandage is much more solid than the preceding ; it should be employed in all cases where it is necessary to exercise pressure over the fionto-ooulo-nasal region.
Application. — Place the initial end of the bandage above the right eyebrow, and fix it by a horizontal circular turn around the forehead (I, 2). Arrived at the nape, pass below the right ear, gain the angle of the right lower jaw; ascend obliquely over the cheek, the internal angle of the eye, and the left parietal protuberance, taking the precaution to pass the bandage between it and the pavilion of the ear (3). From thence gain the nape, ascend obliquely towards the summit of the right parietal protuberance, descend towards the root of the nose, the externa] angle of the left eye, and the left angle of the lower jaw (4). Return then to the nape, and fix the two obliques by a circle around the forehead (5). The nape reached, gain the right angle of the lower jaw, and make a second oblique, which will cover the first for two-thirds, from the internal angle of the eye towards the external angle (6) ;
gain the left parietal protuberance, and cover the ^rst plane of bandage from below upwards; regain then the right parietal protuberance by acting in an inverse sense — that is to say, by covering the plane of the bandage (4) from above downwards (7); cover the left eye, make a fourth circle of the forehead (8), then two new obliques (9, lOj, and terminate by circular turns around the forehead (11).
Application. — Place the face of the bandage upon the anterior and middle part of the forehead, above the eyebrows (1, T); direct the two rollers above the cars, descend lo the na|,e, intercross the two rollers by reversinsr the inferior (1, 2, minor fig. 7) upon the superior (!', 2', minor fig. 7 ). Change them from hand to hand, bring them back upon the angles of the jaw, ascend obliquely over the cheeks and the root of the nose, where you will intercross in the form of an X, by passing the one held in the right hand below the other (2, 2'). Change hands with the rollers, and direct them over the parietal protuberances, in order to descend to the posterior part of the occiput, where you will intercross them again by repeating the reverse. From thence, after having changed hands again with the rollers, bring them back horizontally over the forehead, where you will intercross them by reversing the inferior over the superior (8, 8'); conduct them to the nape, in order, after having crossed them, to bring them back over the angles of the jaw. Repeat in this way, four or five times, the intercrossings at the nape, the X of the nose and the horizontals of the forehead (4, 4', 5, 5', 6, 6', 7, 7', !^, 8' ), and terminate by circular turns around the head, in order to i^cure the diflferent planes of the bandage, as indicated at page 8.
Uses. — The double cross fulfills for both eyes the same indications as in the single cross for one eye. The first variety is far less solid than the second ; the latter, on the other hand, is much more difficult of application.
Application. — Make two horizontal circular turns of the forehead (1, 2). Arrived at the nape, pass under the right ear, if the disease for which the bandage is applied is on the left side, and vice versa if it is on the right; then under the chin ; from whence you will mount towards the left temple in passing over the angle of the jaw; from then.ce ascend directly, between the anterior part of the ear and the external angle of the eye, to the vertex (3) ; from whence you will take an oblique direction towards the right ear, over which you will pass the bandage : then pass again under the chin, to return to the vertex, continuing to direct the bandage between the left ear and the external angle of the orbit (4) ; pass again over the right ear, return under the chin and over the vertex, in order to repeat a third vertical circle (5). Having arrived under the chin, direct your roller towards the nape (6), so as to bring it back to the forehead, in order to make a horizontal circle (7) ; arrived at the nape, conduct your bandage over the chin by passing immediately beneath the lower lip (8) ; make a second circle similar to this last (9), but a fraction of an inch lower. From the nape, pass under the chin, taking care to include a part of the lower border of the preceding turn between it and the ehin ; then, after having made a fourth and fifth vertical circle (10, 11), return under the chin, gain the nape (12), and finish by circular turns around the head (lo),.
Uses. — This bandage is em^t/loyed to insure immobility of the lower jaw in cases of fracture and luxation. It will also answer for maintaining topical applications upon and under the chin, as well as over the parotid region.
Application. — Make two horizontal circular turns of the forehead (1, 2) ; arrived at the nape, conduct the bandage obliquely under the right ear, make a semi- circle of the neck (3), pass under the chin, then cover the left angle of the lower jaw, and ascend, in passing between the external angle of the eye and the anterior part of the ear, towards the forehead. Direct then your bandage obliquely between it and the summit of the head, so as to reach the right parietal protuberance and the nape (4) ; i'rom thence come over the left parietal protuberance, pass again between the forehead and the summit of the head, and descend, after having crossed the turn (4), under the chin in passing behind the right angle of the lower jaw (5). From the chin, pass again over the left angle of the lower jaw, ascend again to the forehead, regain obliquely the nape (6), the left parietal protuberance, the right angle of the lower jaw and the chin (7), in crossing the turn (G). From the chin, pass again, for the third time, over the left angle of the lower jaw, so as to ascend again to the forehead ; descend to the nape (><)., return over the left parietal protuberance, over the right angle of the lower jaw, and redescend to the chin (9), in such a way as to have three vertical obliques behind each angle of the jaw and six obliques between the forehead and the summit of the head. From the chin, gain the nape ; then make a horizontal circle of the forehead (10), in order to fill all the turns; arrived at the nape, make a circle of the neck (11) j then, when this circle shall have reached the nape, conduct the bandage directly beneath the right ear, from thcDce over the chin, in passing immediately beneath the lower lip (12). Repeat this operation a second time, as for the simple cross (13); then make a semi-circle of the neck (14) so as to gain the left angle of the jaw; ascend again to the forehead, descend obliquely to the nape (15), pass over the left parietal protuberance, the right angle of the lower jaw, under the chin (16), over the left angle of the lower jaw, and ascend again between the forehead and the summit of the head ; gain the nape (17), the left parietal protuberance, redescend under the chin (18), and terminate by circular turns around the head (19).
C'ses. — This bandage is employed in cases of luxation or of double fractures of the body and neck of the lower jaw. Applied as we have just described it, this bandage is much more
to two inches broad, rolled into two heads of unequal size.
Application. — After having applied the face of the bandage intermediate between the two rollers over the middle of the forehead (1, 1'); direct the rollers obliquely above the ears so as to descend to the nape^ where you will intercross them in changing them from hand to hand ; from thence carry them under the chin {21), where you will intercross them by simply passing one below the other, so as to mount to the right and the left in covering the angles of the lower jaw, as far as the anterior and superior part of the forehead, where you will intercross them anew by reversing the superior (2, 2) ; then carry each of the two rollers to the nape in making the inferior bandage pass between the right parietal protuberance and the ear (3') and the bandage which has been reversed over the left parietal protuberance. At the nape, intercross each roller a second time so as to return under the chin (3) ; ascend over the angles of the lower jaw, intercross them over the forehead (4', 4'), and redescend to the nape (4) ; from the nape return a third time under the chin (5'), over the angles of the lower jaw, the forehead, and again to the nape (5, 5), in acting as we have indicated. Arrived at this point, leave the bandage which ought to make the reverse in repose, and make with the one which covers it a circle around the forehead (6), in order to inclose on each side the six obliques; then, when the circular shall have returned to the nape, make the reverse, and direct the two rollers simultaneously in front of the. chin, in order to embrace it; these, in order to avoid puckering, reverse the inferior bandage over the superior. From the chin, direct each roller towards the nape, intercross them, gain the under part of the chin (8), the angles of the jaw, the forehead, and again the nape (8', 8); repeat a second time the same manoeuvre (9', 10, 10) ; and terminate by stopping the roller (11') with the roller (11), which should make several circular turns around the head, in order to secure all the circumvolutions.
BANDAGJCS FOU THfc HJtAD. 21
Uses. — They are the same as those of the preceding bandage. The double cross for the jaw with two rollers is still more solid than that applied with one roller, but it is necessary to employ a great deal of care in its applicatiou which is excessively difficult.
Application. — If the bandage is to be applied over the right temple, make two horizoutul* circular turns around the forehead, placing the initial end above the right eyebrow (1, 2) ; arrived behind thr^ right oar. secure the turn with a pin, and make a reverse with it from above downwards (o), in order to direct the bandage under the chin. From thence mount by passing over the left ear to the vertex, descend to the right, covering half of the reverse, regain the under part of the chin (4), so as to make in the same manner three or four vertical circles, or even more, if necessary (5, 0, 7, 8). "When the parts are sufficiently covered, secure the last vertical circle in front of the temple with a pin, then make a second reverse (0), in order to direct the bandage towards the opposite temple, and maintain the whole by horizontal circular turns around the forehead.
0'.>\. — This bandage is very convenient; it is frequently emploj'ed to maintain topical applications in di>cases of the ear, of the parotid gland, and of the submaxillary and suprahyoid regions.
Application. — ^ Apply the face of the bandage horizontally over the diseased temple, the left temple f^r example; direct the two rollers towards the right temple (1, 1') where you will intercross them by reversing the superior over the inferior, then bring them back over the diseased temple (2, 2').
these form an car by twisting one over the other, and changing their direction in such a manner that one may be directed under the chin (3') and the other over the summit of the head (3), from whence they will come to be intercrossed again over the right temple, to gain a second time the under surface of the chin, the summit of the head and the left temple (4, 4'). Form then a second ear like the first, but in an inverse sense, that is to say by directing the rollers horizontally, the one over the forehead and the other over the nape (5, 5') as far as the right temple, from whence, after having,^intercrosscd them, they will be brought back over the left temple (6, 6') to make there a third ear like the first (7, 7'), make then a fourth ear like the second and terminate by horizontal circular turns around the forehead with the aid of the largest roller. Uses. — This bandage is recommended for exerting compression in the case of lesion of the temporal artery ; its action is aided by placing on each side of the wound a small graduated compress (a, e). Destined to remain in place until the obliteration of the artery and to be tighter than any other of the head, it must be applied with care and watched attentively in order to avoid the accidents which too great a compression might occasion.
Aj^pliratioiL. — Apply the face of the bandage over the anterior part of the forehead (1, 1'), direct the rollers above the eyebrows and the ears in descending obliquely to the nape where you will intercross them by reversing the inferior over the superior, in sueh a way as to bring the first from the occiput to the root of the nose (2) in passing over the summit of the head, following the track of the sagittal suture (the name recurrent is given to this turn of the bandage). Then make with the second a horizontal semi-circle of the forehead (2) in order to fix the reversed turn. Thus fixed, this is raised up over the circular to make a second recurrent which you will direct this time from the forehead to the nape in going from left to right and in covering the first for the third of its breadth (3); fix to the nape this second recurrent by a
horizontal semi-circle, make a third reversed turn towards the forehead in directing it from right to left (4) and fix it by a horizontal semi-circle (3'). Continue thus, and make successively from left to right and from right to left reversed turns from the forehead to the nape and from the nape to the forehead, in taking care to dispose them in the form of slices of melon and to secure them by circular turns until the head is completely covered (5, 6, 7, 8, 9, 10, 11, 5' 6'), then terminate the bandage by two or three horizontal circular turns with the aid of the roller (7').
Cscs. — Recourse is had to this bandage in case of wounds of the scalp, to support the sutures or topical applications to this region. It is a very elegant bandage, but is rarely used, because in order to give solidity it is necessary to apply it very tightly.
The recurrent of the head may also be executed with a single roller ; this variety does not differ from the other except in the manner of maintaining the reverse?. We will describe it in detail when we come to consider the bandages for amputation,, for which it is more particularly employed.
Componition. — A bandage two yards long and one and a quarter inches wide, to the middle of which is sewed perpendicularly, and at the distance of one and a quarter inches one from the other, two other ))andagcs half a yard long and Ibur-tit'ths of an inch broad.
AppJication. — Apply over the upper lip the" portion of the transverse bandage between the two perpendicular ones, and conduct each extremity, passing below the ears (b, 1, 1'), to the nape, where you will confide them to an assistant, after having intercrossed themj then carry obliquely as far as the root of the nose the two perpendicular bands, cross them, carry them over the forehead (A, a), the summit of the head, leaving between them an interval of one and a quarter inches. From the summit of the head direct them towards the nape, when you will secure them by a knot, after having passed them the one beneath, the other above the transverse band. Then take the two rollers of the latter (b', b*), from the hands of the assistant, and bring them around the forehead,
Qymposition. — 1st. A bandaare three yards long and fourfifths of an inch wide, made into a double roller. 2d. A long, double corapres-^, one and a half yards long and two and a half inches broad. 3d. Two graduated prismatic compresses-, two and a half inches lono: and one and a half inches broad, and having a thickness of from two and half to three inches, according to the greater or less i^alieucy of the cheeks.
Application.— WdtQ the graduated compresses (b, b) in the hollow below the check-bone, half an inch from the labial commissures ; have them held by an assistant who, placed behind the patient, approsimates them as much as possible without deranging them, in such a manner as to relax the upper lip ; then apply the centre of the long compress over the summit of the head, bring the extremities under the chin in passing over the graduated compresses, and have them held temporarily by the hand of an assistant or of the patient. Apply then the centre of the double roller bandage over the forehead (1, 1'), direct the two rollers to the nape, from whence, after having intercrossed them and changed hands, 3^ou will bring them back in passing above the long compress and the graduated compresses which the assistant then ceases to hold, over the upper lip, at the centre of which one of the pollers will pass through a transverse slit previously made in one of the bandages (2. 2') ) then draw with sufi&cient force upon the rollers, carry them back to the nape to be intercrossed again, and bring them back a second time in front of the upper lip (3, 3'), then to the nape where you will confide them to an assistant. That done, take hold yourself of the ends of the long compress, cross them under the chin ; carry them, in covering on both sides the bandages and graduated compresses to the vertex, where you will intercross them once more in order to fix them over the temples by means of pins ;
then take hold again of the two rollers at the nape, carry taVLXtS. ""'"'' ''°' ^™"*'* '' -era,''h;riz„S: Uses.— This bandage is resorted to to aid the action of su( ores in approximating the edges of wounds of the upper lip, ^^hethPr after a traumatic lesion, or after the operation for
broad.
Application. — Place the initial end (1) about the middle of the injured arm — the right for example — and secure it by two or three circular turns (2, 3 ) j arrived at the posterior and internal part of this member, ascend behind the shoulder so as to reach its superior part ; from thence descend to the axilla of the sound side, by passing obliquely in front of the chest (4), ascend obliquely behind the back, gain the superior part of the diseased shoulder, and descend under the. axilla of the same side, crossing the first turn (5, 5). Ascend again over the shoulder, re-descend to the sound axilla, ascend again behind the back, over the diseased shoulder; re-descend under the axilla of this side, and continue to act thus (8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14) until the bandage is exhausted, when the terminal end is to be secured to one of the turns, either on the anterior or posterior aspect of the chest. Thus applied, this bandage constitutes the descending spictty because the turns of the bandage cover each other from above downwards, from the upper part of the shoulder to its lower; it may be applied in an inverse sense, or from below upwards ; it then takes the name of ascending spica. The first appears to us preferable, being firmer and more regular.
Application. — Fix the initial end (1) by two circular turns at the upper part of the right arm (2, 3); having reached the internal and posterior part of this member, mount behind the right shoulder and gain its superior part; then guide youself obliquely in front of the chest, so as to descend under the left axilla, (4, 4), ascend behind it, thence over the shoulder, and descend, crossing the first turn, under the right axilla (5, 5). Now mount again over the shoulder of this side, pass obliquely in front of the chest, come under the left axilla ((5, 6), over the shoulder, in front of the chest to reach the right axilla by crossing the preceding turns (7, 7), and continue thus until there is a sufficient number of crosses in front of the sternum (8, 8, 9, 9, 10). Finish the bandage by securing the terminal end indifferently over the one or the other shoulder.
Uses. — This bandage serves to preserve contact of the fragments of the sternum in fractures of the upper part of this bone ; it is also employed to dress burns between the shoulders, in order to prevent bad cicatrization ] lastly, it will serve to maintain reduced luxations of the internal end of the clavicle forwards. In the two latter circumstances, its object is to draw the shoulders forward; it is therefore necessary to place them in this position before commencing it, and to maintain them so by the aid of an assistant during thcT whole of its application. It is useful, in order to prevent the inconvenient pressure exerted in front and especially behind the axilla, to protect these parts with wadding.
Appjlication. — Make first, from before backwards and from right to left, two or three horizontal circular turns around the abdomen (1,'2, 3); having arrived above the ^crest of the
rig"ht ilium, take an oblique direction towards the left groin, and gain the external face of the thigh of the same side (4, 4, 4) ; pass behind it, come to its internal side, mount over by passing over the left groin to above the left trochanter major (5, 5); make behind a semi-circle of the abdomen; arrived over the right trochanter major, descend in covering the right groin to the internal part of the corresponding thigh (6, 6) ; wind behind it, and ascend obliquely towards the crest of the left ilium (7, 7, 7) ; practise a posterior abdominal semi-circle ; then, from the right iliac spine, gain the external part of the left thigh (8, 8, 8); get to its internal side, ascend to the left trochanter major (9, 9), practise a posterior abdominal semi-circle, pass over the right trochanter major, descend obliquely to the internal part of the thigh of the same side (10, 10), get to its external face, and ascend over the left iliac spine (11, 11, 11) ; continue in this way until the groins are sufficiently covered (12, 12, 12, 18, 14, 14, 15, 15), then terminate with the roller (16) by circles around the abdomen.
Instead of making the cross in t^iis way by ascending (ascending spied), it may be executed, as in the succeeding case, by working it from above downwards {descending sjpica).
The spica for both groins may be also applied with a doubleheaded roller. Fo» this purpose the centre of the bandage is placed over the last lumbar vertebrae, and after having made two or three circular turns around the abdomen, crossing the turns alternately in front and behind, one of the rollers is directed from right to left and the other from left to right towards the iliac spines; from thence the external face of each thigh is gained, crossing the bandage above the pubis. Wind round the posterior face of each thigh and gain their internal side; ascend, passing obliquely over the groins, to the great trochanters, and, after having crossed the bandage over the loins, direct the rollers again towards the iliac spines, to descend again towards the external face of the thighs, reascend over the groins, gain the loins, and continue thus the number of turns necessary to cover the injured regions. The cross for both groins, with the double roller, does not compensate by any advantage the difficulties of its application; it is with much trouble, and only by subjecting the patient to painful movements, that we can make the crossing over the
Application. — The spica may be applied either to the left or right groin. If you wish to cover the latter, begin from right to left of the patient, by making two or three horizontal circular turns around the abdomen (1, 2, 3); then, after having made the bandage pass over the space included between the great trochanter and the crest of the ilium, direct it obliquely towards the iaternal part of the corresponding thigh (4,4); from there pass to its posterior part, following the fold of the buttock, gain its external part, and ascend obliquely, crossing over the first turn of the bandage, towards the great trochanter of the left side (5, o). Make a horizontal half-circle behind the abdomen, bring back your bandage between the great trochanter and the crest of the right ilium, gain obliquely the internal part of the thigh in covering the first turn of the bandage for two-thirds of its width (6, 6j, make a contour with the bandage by its posterior face, come over its external face, and ascend obliquely over the great trochanter of the left side (7, 7) ; make a new contour of the abdomen behind, redescend to the internal part of the right thigh, mount again over the great trochanter of the left side, make a third posterior abdominal circle, and continue thus as often as may be necessary for covering the right groin completely (8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17). Finish, lastly, with the roller (18) by circular turns around the trunk.
Uses. — This bandage may be employed for maintaining topical applications and all sorts of dressings over the groin; it is, nevertheless, generally reserved for those circumstances in which it is necessary to exert a solid and regular pressure over this region, when there is question, for example, of compressing engorged glands, producing pressure upon fistulous tracts, maintaining a hernia, etc. ; in these different cases it
presses between it and the points of compression.
Thus applied, this bandage constitutes the ascending sjpica. The descending spica is executed by, instead of directing the first oblique towards the point where you wish the bandage to stop below, placing it at the superior part of the thigh, and continuing the crosses from above downwards. These two modes of application of the spica for the groin may be indifferently employed ; there is no reason, that we can perceive, for prefering the one over the other.
about an inch wide.
Application — If you wish to cover one of the fingers of the right hand, after having placed the hand in a state of pronation, leave several inches of the initial end hanging on the ulnar side of the wrist, and make two or three circular turns around it (1, 'jJ) ; having arrived at the articulation of the fifth metacarpal bone with the unciform, descend obliquely towards the external side of the base of thej finger (3, 3), make several digressing turns to gain the end of the finger (4), from whence you will ascend to its base by making successive turns covering each other for two-thirds of their width (5, 6, 7, 8, 9, 10, 11); then, when the last turn shall have reached the internal side of the finger, pass over the back of the hand, wind round the first metacarpal bone about its middle (12), and reach the ulnar side of the wrist (13), where you will tie the initial and terminal ends together (14, 15).
half inches wide.
Application. — Fix the initial end at the extremity of the fingers (1, 2); ascend from thence towards the wrist, making, at the base of the thumb, proper reverses, so as to give to the
bandage sufficient solidity and regularity (3, 4, 5, 6, 7, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15), and finish by circular turns around the wrist (16, 17, 18).
an inch broad.
Application.— 'Mi^x having placed the hand in a state of semi-pronation, allow to hang on the ulnar side of the forearm, if it is the right wrist and thumb that you wish to cover, several inches of the initial end, gain the radial side of the wrist, and make one or two circular turns around it (1, 2, 3); having reached the upper extremity ef the fifth metacarpal bone, descend obliquely towards the external side of the articulation of the first with the second phalanx of the thumb (4, 4), come to its internal side and ascend, crossing the first turn, to the ^ternal side of the lower extremity of the first metacarpal bone (5, 5)j then make a horizontal semi- circle over the palmar surface of the wrist, so as to bring the bandage over the carpal articulation of the fifth metacarpal bone ; from thence gain obliquely the external face of the second phalanx of the thumb, covering the oblique (4) two-thirds (6, 6) ; come again to the internal side of t^hts phalanx, and ascend a second time obliquely towards the middle and external side of the first metacarpal bone (7, 7); go again over the palmar face of the wrist, redesccnd to the external part of the base of the thumb (8, 8), ascend again over the lower extremity' of the first metacarpal bone (9, 9), make a third semi-circle of the wrist; then^ after having continued the obliques around the thumb until its metacarpo-phalangeal articulation is completely covered (10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15), come again to the ulnar side of the forearm, where you will tie together the terminal end (16) with the initial end.
farther useful to secure extension of this member after reduction of the luxation backwards of the first metacarpal boRe from the trapezium. Like all the spicas, it may be applied from above downwards; that is to say, in directing the crosses ftom the base towards the summit of the thumb ; but this desrtnding spica is much less regular than the ascending spica, which we have just described.
Appliration . — Place the hand in a state of pronation, and fix the initial end of the bandage over the dorsal aspect of the' wrist by a horizontal circular turn (1, 2), following the direction from the radius to the ulna, if the bandage is applied to the left hand, then carry the roller obliquely over the back of the hand ; from thence conduct it, after having made a horizontal circular turn around the fingers (4), between the thumb and the index finger, from whence you will ascend obliquely over the back of the hand (5, 5), crossing the turn (8); make a horizontal circle around the wrist (6), repass obliquely over the back of the hand (7, 7,) circularly around the base of the fingers (8), come again between the thumb and the index finger, to ascend anew obliquely over the back of the hand (9), and, after having continued thus until the bandage is exhausted, terminate by circular turns around the wrist (10).
Uses. — Recourse is had to this bandage for maintaining the apparatus over the dorsal aspect of the hand and wrist ; it may equally serve to fix a graduated compress, destined to exercise compression, whether over a ganglion or over the 03 magnum, after reduction of its luxation backwards, or over the salvatella. to arrest the flow of blood after bleeding from this vein.
Application — Leave a tail of bandage^ ten inches long, free over the external and lower side of the right arm ; then, after having directed it towards the internal side, fix it by a circular turii (2); having arrived above the external condyle, gain obliquely the internal and upper side of the fore-arm (3), surround it with a horizontal circle (4), and ascend obliquely, in crossing in front of the bend of the arm, the turn (3), as far as the internal condyle (5) ; make a horizontal semi-circle backwards, pass again over the fold of the arm (6), circularly behind the fore-arm ; mount again obUquely towards the internal condyle (7), and terminate by tying the terminal end (8) and the initial end together on the outside of the arm.
Uses.: — The eight bandage for the elbow is in daily use to secure the small compress placed over the vein after venesection from the arm ; its circumvolutions leave full liberty of motion to the elbow, and allow it to be maintained in a semiflexed position until the healing of the wound.
Application. — After having placed the hand in the extended position, apply the intermediate face of the bandage over the dorsal aspect, then direct the two rollers towards the palmar face (1, 1'), where you will cross them, changing them from hand to hand; from there bring them back over the dorsal aspect, where you will cross them anew (2, 2'), so as to conduct them and cross them again over the palmar surface ; direct them then obliquely the one above the external condyle (o, 3)^ the other above the internal condyle (3' 3'),
crossing them, like the letter X, at the middle of the forearm, make a horizontal circle with your two rollers above the elbow (4, 4') ; come again above the external and internal condyles, descend obliquely towards the hand, crossing the turns again, like the letter X, at the middle of the fore-arm (5, 5, 5', 5') ; cross your bands over the palm of the hand (6, 6'), and finish by ascending towards the elbow and descending towards the hand until the bandage is exhausted. . Uses. — This bandage is employed, in the case of burns of the palmar aspect of the hand and wrist, to prevent flexion of the parts from contraction of the cicatrices.
When the burns are situated upon the back of the wrist or hand, if you wish to iffevent contraction of the cicatrices from producing extension of the hand upon the fore-arm, the flexing figure of eight for the hand must be resorted to. In order to apply it, the hand is placed in the flexed position, and the intermediate face of the bandage between the two rollers is placed over the palmar surface; the two rollers are then directed towards the dorsal aspect, then again towards the palm, fpom the hand towards the elbow and from the elbow towards the hand, alternately representing the letter X over the middle of the ^terior surface of the fore-arm.
Application. — Place the face of the bandage intermediate to the two rollers under the axilla of the sound side, then conduct each roller above the upper part of the wound going obliquely from below upwards, one behind, the other in front of the chest (1, 1') ; arrived there, change them from hand to hand for the purpose of crossing them; gain, from before backwards with the one held in the right hand, the posterior and inferior part of the wound (!'), conduct at the same time the one in the left hand under the sound axilla, turn the lat-
36k OK njLHHAQtva. .
ter, and come to fix inferiorlj by a horizontal circular turn of the chest the first oblique or recurrent turn (1' 1') (2 2) ; then raise the latter, and after having embraced in the form of a loop the turn (2), direct it obliquely from below upwards towards the superior part of the wound (2'), where you will fix it with the turn (3) which you will have conducted over it in parting from and returning towards the sound axilla after having covered successively from below upwards and from above downwards the posterior and anterior walls of the thorax (3, 3). Make now a third descending recurrent (3'), fix it by a second horizontal circle (4), then practice a fourth ascending recurrent (4'), over which you will pass anew a turn parting from and returning towards the sound axilla (5). Contiaue thus until the wound and 'dressings have been completely covered (5', 6, 6, 7, 7', 8, 8', 9, 9V10, 10', 11, 11'), and terminate by making horizontal circular turns around the chest with the roller (12). *
Uses. — -This bandage, as simple as elegant, is very convenient for maintaining topical applications or apparatus, after disarticulation at the shoulder-joint.
Application.— The fore-arm being bent at a right single upon the arm, place the base of the triangle under the hand (a), directing the apex towards the elbow, then make the ends ascend obliquely, the one in front (b) the other behind the chest to the sound shoulder where you will tie them together (c) ; gather up the angles at the apex and carry them, embracing the arm and elbow (d, e, g, h), in front of the chest to be secured by a pin to the body of the bandage (r).
upon which will be sewed perpendicularly two other bandages, a little shorter and proportion ably narrower, one about two and a half inches from the initial end (c, minor fig. 28), and the other at nearly twice the distance from the same end (b, minor figure 28). For the simple T the two supplementary bands will be replaced by a single one which will be sewed perpendicularly upon the transverse band, but at the distance of about four and a half inches from the initial end.
Application. — If you wish to apply the double T, place the initial end of the transverse band over the back of the wrist in such a manner that the two perpendicular bands correspond to the interdigital spaces of the fourth and fifth and the first and second fingers (a', a-, b*, c\ figure 28) ; conduct this iatter one between the thumb and the index (c\) the other bgtween the ring and the little finger (b^), then direct them towards the palmar face of the wrist, where you will fix them by passing the transverse band circularly around them (a'); from thence bring them back to the back of the. wrist, traversing with the one the third (B), and vf^xh the other the second interdigital space (c^). Fix this latter by a horizontal circular turn (a^), reverse it in the form of an ear (c^) over this circular, proceed to tic it over the back of the wrist with the first (b), and finish by fixing the terminal end of the transverse band with a pin (.\^). The simple T is applied in the same manner, but only two interdigital spaces are covered with the perpendicular band.
Csfs. — The double T retains more firmly than the simple T dressings over the back and palm of the hand ; both serve to prevent union between the fingers, so apt to take place in the cicatrization from burns. The simple T acts only upon two, while the double T acts upon the four interdigital spaces.
Application. — If you wish to apply this bandage over the right limb, begin at the base of the toes, making a certain number of turns, interrupted by the necessary reverses (1, 2, 3, 4, 5, 6, 7, 8). Having reached the instep, direct your bandage obliquely over the summit of the heel (9), then again over the instep, from whence you will come, passing under the sole, to cover, in front of the heel, the^ anterior border of the preceding turn (10) ; then gain, obliquely, the upper part of the tibio-tarsal articulation (10, 10), pass behind the tendo-Achillis, and .cover, on the back of the heel, the posterior border of the band 9 (11). From this point, gain obliquely the instep (11, 11), pass circularly over the plantar surface and gain, for the fourth time, the instep, in order to cross at this point the preceding turn (12). From the instep, direct yourself over the internal malleolus, behind the tendo-Achillis, pass from behind forwards and transversely under the external malleolus (13), under the sole of the foot, and ascend over the instep, in order to proceed from there to cross from l)efore backwards over the tendo-Achillis the turn 13 (14, 14); from the tendo-Achillis come again over the instep, pass over the plantar surface (15), cover from before backwards and transversely the under part of the internal malleolus, then surround the leg circularly (16, 17, 18, 19). That done, proceed with circular and- reversed turns to the lower border of the patella (20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29,
BAKDAOES FOR LOWBR EXTREMITIES. 39
30, 30, 31, 32, 33, 34, 35), which you will cover by the aid of superior and inferior crosses. To do this, direct your bandage obliquely from below upwards from the upper and outer part of the leg towards the summit of tlie internal tuberosity of the tibia (36), surround the back of the knee, and after having covered the external tuberosity of the tibia, gain obliquely, by crossing the preceding oblique below the patella, the upper and internal part of the leg (37) ; repeat this operation two or three times (38, 39, 40, 41, 42), then gain, by crossing obliquely the popliteal space, the outer and lower part of the thigh, which you will surround with a horizontal circular (43). Having reached the outer and lower face of the thigh, descend obliquely towards the internal condyle of the femur f44), cover the knee behind, pass over the external femoral condyle and gain, by crossing obliquely from below upwards above the patella the turn (44), the inner and lower face of the thigh (45). Make, in this way, two or three crosses (46, 47, 48, 49, 50), then unite them to the inferior crosses by the aid of a turn which, from the ham, will pass circularly over the patella (51), and ascend behind to the lower and outer part of the thigh. Having reached these, finish your bandage by the aid of new circular and reversed circumvolutions covering the whole upper surface of the thigh (51, 52, 53, 54, 55, 56, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 66, 67, 67, 68). Uses. — The spiral of the lower limb employed with success by Professor Velpeau in the first stage of diffuse phlegmon to obtain resolution of the inflammation and disengorgement of the tissues, is often useful for emptying purulent depots and facilitating adhesion in the parts after long and abundant suppurations. It is also used for varicose veins, oedema, and especially for producing compression throughout the whole extent of a limb when it is desired to treat aneurismal tumor by this means. Generally designated under such circumstances as Thedeiis handagey it is used with a view to compress the diseased points, to prevent the engorgement of parts sit-* uated below, and to modify the flow of blood to the tumor; to achieve the latter result, Theden, before applying the bandage, placed graduated compress over that portion of the artery situated above the aneurism, and covered the tumor with cloths saturated with his astringent wash, called eau d'arquehusade.
The^spiral of the lower limb works loose and becomes easily deranged ; it is moreover very fatiguing on account of the compression it produces, and which may determine gangrene when it is not evenly applied. These inconveniences are obviated by remedying the inequalities of the limb with wadding or tow, and securing the circumvolutions by the application of starch.
Application.- — Place the initial end three or four fingers breadth above the malleoli, over the anterior part of tbe leg, and fix it by a horizontal circular turn (1, 2) ; arrived above the internal malleolus, gain obliquely the articulation of the fifth metatarsal with the cuboid bone (3), surround the sole and back of the foot by a horizontal circular (4) and ascend obliquely, crossing over the instep tlie preceeding turn, to the external malleolus (6) ; make behind the leg a horizontal semi-circle, cover the instep again obliquely (6) and the plantar surface circularly, then ascend again over the external malleolus (7) ; continue thus until the small compress which you have previously placed over the vein is firmly fixed, and finish by horizontal circular turns around the leg with the roller (8>
f '6^^8.— This bandage may be used for maintaining dressings over the dorsal and plantar aspects of the foot, and also over the tibio-tarsal articulation, but is more particularly resorted to for compressing the opening in the saphenous vein after bleeding from the foot.
Application, — Fix the initial end by a horizontal circular turn above the knee (1, 2) ; having arrived above the external condyle of the femur, descend obliquely behind the ham to the internal tuberosity of the tibia (3) ; surround the upper
part of the leg with a horizontal circle (4), then ascend obliquely, crossiog like the letter X over the popliteal space the preceding oblique, as far as the iuternal condyle of the femur (5); make a horizontal semi-circle over the anterior and lower part of the thigh, pass again obliquely over the ham (6), circularly over the anterior and upper part of the leg, ascend again over the internal condyle of the femur (7), and continue thus to the entire expending of the bandage (8).
Usf's. — This bandage is employed for dressings over the ham ; it may be also used for compressing the popliteal artery affected with spontaneous or traumatic aneurism.
Application. — The amputation terminated, the wound covered with lint, and this sustained by a compress, .shaped like a Maltese cross, fix the initial end above the stump by several horizontal circular turns (1, 2, 3, 4); arrived over the external side of the thigh (we suppose it to be the right;, reverse the bandage from above downwards (5), so as to make a turn descend over the wound, cover it across and ascend over the opposite side of the limb (6, 6, 6). That done, practise a second reverse, but this time from left to right and from before backwards, which will permit you to cover circularly, in fixing the two reverses, the posterior, external and anterior aspects of the thigh (7, 8, 9). Having reached the middle part of the latter, make a third reverse in the direction of the tirst (10), then a second recurrent, which you will conduct, by crossing the recurrent (6) at a right angle over the middle of the stump, to the posterior face of the thigh (10); then practise, from right to left, a fourthTeverse and two circulars (11, 12); then, when you shall have arrived at the outer side of the third reverse (lOj, commence a fifth reverse (13) and a third recurrent, whidh will cover two-thirds of the second on the outside, and Hke it will be directed from the front to the posterior of the wound (13); maintain this anew by two circular turns (14, 15), and continue in this way your circulars and recurronts alternately until the stump is entirely covered (16, 16, 17, 18, 19, 19, 20, 21, 22, 22, 23, 24, 25).
Finisli by ascending and descending turns, if the amputation has been practised at the lower part of the thigh, or by circles around the pelvis, if the limb has been ablated high up, in order to avoid derangement of the apparatus by the movements of the patient.
The capeline for amputations of the thigh may be applied as follows, with the double-headed rollers unequal in their size, the larger serving for the circulars and the smaller for the recurrents.
Place the intermediate face of the bandage over the anterior face of the member above the stump, then direct them over the opposite face, where you will cross them ; pass again over the a»terior and posterior aspects, making, in this way, three or four circular turns, in order to secure the commencement of the bandage. When the latter reaches one of the sides of the limb, reverse the turn which k above, and conduct it from above downwards, over the most superficial, to form a recurrent, which you will direct transversely over the wound, from the outer to the inner side, if the bandage is applied to the right thigh. Fix this recurrent by a circular turn, then practise a second, which will pass from before backwards, and cross the first over the wound -, confine this second recurrent by a circular, continue in this way until the wound is completely covered, and terminate with the most voluminous roller, as we have indicated for the capeline with the single roller.
The latter capeline is almost entirely abandoned because of its application being more difficult than the other; it may, however, be usefully employed in armies ; it ofi"ers, in effect, much more solidity, an advantage which deserves to be taken into consideration when the patient has to be subjected to rough transportation. '
Composition. — 1st. Two pieces of linen equal in width to the length of the wound, and each as long as the space comprised between the fold of the groin and the lower part of the leg, when the solution of continuity to be re-united is transversely across the anterior region of the thigh. One of these
is to be split at one of its extreTnities, and about the third of its length, into two or three equi-distant tails ; while in the other, at its centre, and in the direction of its length, is made a number of slits equal to the tails of the other. 2d. A bandage eighteen yards long and two inches wide. 3d. Two graduated prismatic compresses made a little longer than the solution of continuity.
AppUcntiov . — The limb being in a position indicated by the wound, place over the anterior surface of the leg, and following its length, the split piece of linea in such a way that the ends shall be turned upwards and the roots correspond to the wound (a, a', a'^); let it be held in this position by an assistant, while you apply a roller bandage around the leg to within two inches of the solution of continuity (1, 2, 3, 4, 4, r>, 5, 6, 6, 7, 7, 8, S, 9, 9, 10, 10, 11, 11, 12,*13, 14, 15, 16, 17). Then confide the roller to the assistant, and apply the second piece of linen over the anterior portion of the thigh in such a way that the slits shall reach the level of the wound (b, b', b'^, c) ; take the roller from the assistant, in order that he may take charge of the latter piece of linen and secure it by a spiral of the thigh (18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 25, 26, 26, 27, 27). That done, confide again the roller (28) to the assistant, place the graduated compress over the edges of the division (d, d', e, e'), pass the tails (a', a*) through the slits (b^, b^), draw them in opposite directions until the edges of the wound are co-aptated, and fix the two pieces of linen in this position by a spiral, descending from the upper part of the thigh to the roots of the toes and covering the limb evenly.
U>ies, — Although constructed upon good principles, this bandage is rarely used to obtain union in transverse wounds of the limbs, for it can nearly always be replaced by more simple means. Applied over the upper extremities, it serves for the treatment of fractures of the olecranon, and over the lower extremities for fracture of the patella.
' Composition. — Three cravats one yard in length. Application. — Place one of the cravats, in the form of a stirrup, over the inst«p, and tie its ends together over the
plantar region (h, I, j) ; fix another over the lower third of the thigh and the upper third of the leg (a, b, b^, c, c^; d)j then introduce at the instep, under the ring formed by the first (e), a third cravat ; carry the ends directly towards the upper and lateral portions of the knee (g, f), and faslen them on each side to the super and sub-patella cravat (g^).
Uses. — Proposed by M. Mayor for fractures of the patella and rupture of the tendon, which fixes this bone to the tibia, this apparatus will also serve for approximating the lips of transverse wounds of the instep, of the leg, and of the knee.
and half a yard deep from apex to base.
Application.— l^hce the middle of the base of the triangle over the anterior face of the limb at a convenient distance from the end of the stump (a), direct and cross under the limb the two ends corresponding to this base (b, c), then bring them forward for the purpose of securing them (b^, c^); then fold the apex of the triangle over the end of the stump and attach it in front with a pin (d).
The tendency of this cravat to slip and become disarranged when placed over a coolcal stump may be prevented in the following manner : 1st. For the thigh, by means of a band going directly from the apparatus to a band around the waist; or otherwise, by directing the two ends of the handkerchief, after liaviog crossed them in front of the limb, to the waistband. 2d. For the ar/ii, the triangle may be fastened around the neck or the axilla of the sound side. 3d. For the forearm and the leg, the two extremities may be carried around the elbow or the knee.
Uses. — This triangle is very convenient for the dressing of amputations; it may advantageously take the place of the numerous turns of bandage required for the application of the capeline.
from base to apex.
Ai^pUcatlon. — Place the base of the triangle over the anterior and inferior portion of the leg (a), take the ends (b), and, after having passed one of them through the ring of the shoulder-band (e, f, g, h,) tie them together at the level of the right or left flank (c), then fold the apex over the side of the knee (l^).
U^€s. — This sling may be employed in all eases where it is necessary to maintain the leg flexed upon the thigh. It maintains flexion, and at the same time enables the patient to go about.
PLATE 1.
Fig. 1. ^fanne^ of commencing the application of the singleheaded roller: A, extremity of the thumb, and the index and middle fingers of the right hand, maintaining the roller; B, thumb and index finger of the left hand fixing the initial end.
Fig. 8. Simple cross for the lower jaw. Fig. 9. Double cross for the lower jaw, with ene roller. Fig. 10. The same bamlage with double roller. Fig. 10 (minor). Manner of making the reverse over the chin in the double cross for the lower jaw, with the double roller. Fig. 11. Cross for the head.
Fig. 29. Spiral for the lower limb (Theden's bandage). Fig. 30. Figure of eight for the foot and leg. Fig. 31. Posterior figure of eight for the knee.
| 16,905 | common-pile/pre_1929_books_filtered | illustratedsyste01goff | public_library | public_library_1929_dolma-0022.json.gz:2575 | https://archive.org/download/illustratedsyste01goff/illustratedsyste01goff_djvu.txt |
1YRF_cozXFOuxKYA | 7.6: Antiparasitic and Anthelminthic Drugs | 7.6: Antiparasitic and Anthelminthic Drugs
By the end of this section, you should be able to:
- 7.6.1 Describe the pathophysiology of common parasitic and helminthic infections.
- 7.6.2 Identify clinical manifestations related to common parasitic and helminthic infections.
- 7.6.3 Identify the etiology and diagnostic studies related to common parasitic and helminthic infections.
- 7.6.4 Identify the characteristics of drugs used to treat common parasitic and helminthic infections.
- 7.6.5 Explain the indications, actions, adverse reactions, and interactions of drugs used to treat common parasitic and helminthic infections.
- 7.6.6 Describe nursing implications of drugs used to treat common parasitic and helminthic infections.
- 7.6.7 Explain the client education related to drugs used to treat common parasitic and helminthic infections.
Parasitic Infections
In the United States, parasitic infections can affect anyone, but they disproportionately affect immunocompromised individuals, members of racial and ethnic minority groups, and those with low income. Parasitic infections are defined by the relationship been the host (human) and the parasite. Common types of parasitic infections are caused by protozoa and helminths.
- Protozoa : Protozoa are unicellular organisms that replicate within a human host. Examples of protozoal infections include those caused by Giardia, Plasmodium , and Babesia . Many of these conditions affect clients living in areas with poor sanitation because the spread can be attributed to either fecal-contaminated water or fecal–oral transfer. Signs and symptoms of protozoal infections include diarrhea, low-grade fever, nausea, greasy stools, and depressed appetite. Intestinal protozoal infections are most often diagnosed from microscopic stool samples, although molecular tests have recently been developed that may allow faster detection of infections.
- Helminths : Helminths, or worms, are large complex organisms that can be consumed while they are in a larval stage and then mature into their adult stage in the host’s gastrointestinal tract. Common signs and symptoms include abdominal pain and diarrhea; however, infections can also be asymptomatic. Similar to protozoal infections, microscopic examination of stool samples can reveal helminth eggs and aid in diagnosis.
Antiparasitic Drugs
This section covers the most frequently used antiparasitic drugs , including their mechanisms, adverse effects, indications, and contraindications. It is important to ensure that an accurate diagnosis has been made regarding the causative organism because this will dictate which medication is most appropriate for the client. Some of the most common antiparasitic drugs include:
- Metronidazole: For Giardia lamblia, Trichomonas vaginalis, Cryptosporidium parvum , and Toxoplasmosis gondii , metronidazole is the drug of choice. It provides good coverage against Entamoeba, Giardia , and Trichomonas , which are the species that cause infection.
- Tinidazole: Tinidazole is structurally related to metronidazole and has similar actions, adverse effects, and interactions. It also has a longer half-life than metronidazole, so dosing is more convenient. However, tinidazole is much more expensive than metronidazole. Tinidazole is contraindicated in clients consuming alcohol while using the drug due to risk for causing a severe flushing reaction.
- Nitazoxanide: Nitazoxanide is an alternative antiparasitic that can be used to treat giardiasis and cryptosporidiosis. Its full mechanism is unknown, but it is thought to disrupt the ability of these microorganisms to undergo anaerobic metabolism, leading to cell death. Nitazoxanide is well tolerated but can cause some gastrointestinal signs and symptoms.
- Scabicides and pediculicides: Scabicides and pediculicides are designed to treat infestations caused by lice and scabies. Lice, depending on the species, can cause symptoms on the head, body, or genitals. Collectively, this condition is known as pediculosis. Lice can be difficult to treat because if the eggs (nits) are not successfully removed from the hair after treatment, reinfestation can occur. Nit combs can be indispensable along with pediculicides. All agents in this category are applied topically to the affected area.
- Permethrin: Permethrin has a wide range of activity against a variety of arthropods, which makes it useful for lice infestations. Permethrin works by causing neuronal hyperpolarization and paralysis in the organism, leading to death.
- Lindane: Lindane has activity against lice and scabies and works by being absorbed into the parasite’s exoskeleton, leading to seizures and death.
- Malathion: Malathion comes from a group of chemicals known as organophosphates, which have been used as agricultural insecticides for many years. It works by inhibiting the enzyme acetylcholinesterase, which is responsible for metabolizing acetylcholine. This causes a buildup of acetylcholine, leading to overstimulation, paralysis, and death of the parasite.
- Spinosad: Spinosad is another topical antiparasitic with activity against scabies and lice. It works by inducing neuronal excitation and eventual paralysis and death of the organism. The most common adverse effects seen with spinosad include redness and skin irritation at the application site.
Clinical Tip
Ensure Removal of Nits
Nits are the eggs of lice that attach to the hair, and they are unaffected by pediculicides. To ensure that nits do not go on to mature into adults requiring further pediculicide treatment, it is important to carefully comb through the hair with a fine-tooth nit comb after using a pediculicide. Shaving the head is a viable alternative, but this is not a desirable outcome for many clients.
Anthelminthic Drugs
The available anthelminthic agents are broad spectrum and can treat a variety of worms, including roundworms, pinworms, hookworms, and whipworms. Because worm infections occur in the gastrointestinal tract, these agents are taken orally.
- Mebendazole: Mebendazole works by inhibiting microtubule formation in susceptible helminths and blocking glucose uptake. This action leads to eventual death of the worm, after which it can be passed through the feces.
- Ivermectin: Ivermectin is an interesting antiparasitic agent because it has activity as both a pediculicide and an antihelminth. When used topically, it can treat lice and scabies infestations; when taken orally, it can treat a variety of helminth infections. Ivermectin works by inhibiting parasite nerve and muscle tissue, causing paralysis and death of the organism.
Table 7.15 lists antiparasitic and anthelminthic drugs and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
|---|---|
| Lindane | Head lice: Apply 30–60 mL shampoo to dry hair and massage into hair for 4 min; add small quantities of water to hair until lather forms, then rinse hair and comb with fine-tooth comb to remove nits. |
|
Mebendazole
( Emverm ) |
Ascariasis: 100 mg orally twice daily for 3 days or 500 mg orally once daily. |
|
Metronidazole
( Flagyl ) |
Giardiasis:
250 mg orally 3 times daily for 5–7 days.
Trichomoniasis: 500 mg orally twice daily for 7 days. Amebiasis: 500 mg orally every 8 hours for 7–10 days. |
|
Nitazoxanide
( Alinia ) |
Giardiasis: 500 mg orally every 12 hours for 3 days. |
|
Permethrin
( Elimite ) |
Head lice: Apply enough lotion or cream to saturate hair. Leave on for 10 min and then rinse with warm water. |
|
Spinosad
( Natroba ) |
Head lice: Apply sufficient amount to cover scalp. |
Adverse Effects and Contraindications
Most oral antiprotozoal and anthelminthic drugs can cause gastrointestinal upset. Any topical scabicides and pediculicides may cause skin irritation to the area where they are applied. Excessive use of lindane is not recommended in high doses, especially in children, because it can cause central nervous system excitation and seizure. Malathion should be kept away from children because ingesting it could cause cholinergic poisoning.
Table 7.16 is a drug prototype table for antiparasitic and anthelminthic drugs featuring metronidazole. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
|
Drug Class
Nitroimidazole Mechanism of Action Causes loss of helical DNA structure and strand breakage to cause cell death |
Drug Dosage
Giardiasis: 250 mg orally 3 times daily for 5–7 days. Trichomoniasis: 500 mg orally twice daily for 7 days. Amebiasis: 500 mg orally every 8 hours for 7–10 days. |
|
Indications
Amebicide Antiprotozoal Therapeutic Effects Reduces symptoms of infection |
Drug Interactions
Disulfiram Fosphenytoin Haloperidol Mebendazole Food Interactions Ethanol |
|
Adverse Effects
Nausea Vaginitis Headache Abdominal pain Diarrhea Xerostomia Dizziness |
Contraindications
Hypersensitivity Caution: Superinfection Hepatic impairment Renal impairment Seizure disorder |
Nursing Implications
The nurse should do the following for clients who are taking antiparasitic or anthelminthic drugs:
- Monitor for signs and symptoms of anaphylaxis (e.g., shortness of breath, difficulty breathing, difficulty swallowing).
- Advise the client to take the entire prescribed course of the medication to ensure adequate treatment and to reduce the development of drug resistance.
- Instruct the client to maintain adequate hydration; monitor kidney function for renally eliminated medications.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Client Teaching Guidelines
The client taking an antiparasitic or anthelminthic drug should:
- Alert their health care provider about any signs of allergic reactions including throat swelling, severe itching, rash, or chest tightness.
- Alert their health care provider that they are taking these medications, including the dose and frequency.
- Take the drug with food if it causes an upset stomach.
- Take a missed dose as soon as they remember; however, they should not take double doses.
- Avoid taking tinidazole or metronidazole with alcohol because the interaction can cause a severe flushing reaction.
FDA Black Box Warning
Lindane Lotion
Seizures and deaths have been reported following repeated or prolonged use and in rare cases following a single application. | 2,031 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Nursing/Pharmacology_for_Nurses_(Openstax)/07%3A_Anti-Infective_Drugs/7.06%3A_Antiparasitic_and_Anthelminthic_Drugs | libretexts | libretexts-0000.json.gz:15110 | https://med.libretexts.org/Bookshelves/Nursing/Pharmacology_for_Nurses_(Openstax)/07%3A_Anti-Infective_Drugs/7.06%3A_Antiparasitic_and_Anthelminthic_Drugs |
t3LIcxQ8_CGrk_Z0 | 13.8: Reading- Personal Selling | 13.8: Reading- Personal Selling
People Power
Personal selling uses in-person interaction to sell products and services. This type of communication is carried out by sales representatives, who are the personal connection between a buyer and a company or a company’s products or services. Salespeople not only inform potential customers about a company’s product or services, they also use their power of persuasion and remind customers of product characteristics, service agreements, prices, deals, and much more. In addition to enhancing customer relationships, this type of marketing communications tool can be a powerful source of customer feedback, as well. Later we’ll cover marketing alignment with the sales process in greater detail. This section focuses on personal selling as one possible tool in the promotional mix.
Effective personal selling addresses the buyer’s needs and preferences without making him or her feel pressured. Good salespeople offer advice, information, and recommendations, and they can help buyers save money and time during the decision process. The seller should give honest responses to any questions or objections the buyer has and show that he cares more about meeting the buyer’s needs than making the sale. Attending to these aspects of personal selling contributes to a strong, trusting relationship between buyer and seller. [1]
Common Personal Selling Techniques
Common personal selling tools and techniques include the following:
- Sales presentations : in-person or virtual presentations to inform prospective customers about a product, service, or organization
- Conversations : relationship-building dialogue with prospective buyers for the purposes of influencing or making sales
- Demonstrations : demonstrating how a product or service works and the benefits it offers, highlighting advantageous features and how the offering solves problems the customer encounters
- Addressing objections : identifying and addressing the concerns of prospective customers, to remove any perceived obstacles to making a purchase
- Field selling : sales calls by a sales representative to connect with target customers in person or via phone
- Retail selling : in-store assistance from a sales clerk to help customers find, select, and purchase products that meet their needs
- Door-to-door selling : offering products for sale by going door-to-door in a neighborhood
- Consultative selling : consultation with a prospective customer, where a sales representative (or consultant) learns about the problems the customer wants to solve and recommends solutions to the customer’s particular problem
- Reference selling : using satisfied customers and their positive experiences to convince target customers to purchase a product or service
Personal selling minimizes wasted effort, promotes sales, and boosts word-of-mouth marketing. Also, personal selling measures marketing return on investment (ROI) better than most tools, and it can give insight into customers’ habits and their responses to a particular marketing campaign or product offer.
When to Use Personal Selling
Not every product or service is a good fit for personal selling. It’s an expensive technique because the proceeds of the person-to-person sales must cover the salary of the sales representative—on top of all the other costs of doing business. Whether or not a company uses personal selling as part of its marketing mix depends on its business model. Most often companies use personal selling when their products or services are highly technical, specialized, or costly—such as complex software systems, business consulting services, homes, and automobiles.
In addition, there are certain conditions that favor personal selling: [2]
- Product situation : Personal selling is relatively more effective and economical when a product is of a high unit value, when it is in the introductory stage of its life cycle, when it requires personal attention to match consumer needs, or when it requires product demonstration or after-sales services.
- Market situation : Personal selling is effective when a firm serves a small number of large-size buyers or a small/local market. Also, it can be used effectively when an indirect channel of distribution is used for selling to agents or middlemen.
- Company situation : Personal selling is best utilized when a firm is not in a good position to use impersonal communication media, or it cannot afford to have a large and regular advertising outlay.
- Consumer behavior situation : Personal selling should be adopted by a company when purchases are valuable but infrequent, or when competition is at such a level that consumers require persuasion and follow-up.
It’s important to keep in mind that personal selling is most effective when a company has established an effective sales-force management system together with a sales force of the right design, size, and structure. Recruitment, selection, training, supervision, and evaluation of the sales force also obviously play an important role in the effectiveness of this marketing communication method. [3]
Advantages and Disadvantages of Personal Selling
The most significant strength of personal selling is its flexibility. Salespeople can tailor their presentations to fit the needs, motives, and behavior of individual customers. A salesperson can gauge the customer’s reaction to a sales approach and immediately adjust the message to facilitate better understanding.
Personal selling also minimizes wasted effort. Advertisers can spend a lot of time and money on a mass-marketing message that reaches many people outside the target market (but doesn’t result in additional sales). In personal selling, the sales force pinpoints the target market, makes a contact, and focuses effort that has a strong probability of leading to a sale.
As mentioned above, an additional strength of personal selling is that measuring marketing effectiveness and determining ROI are far more straightforward for personal selling than for other marketing communication tools—where recall or attitude change is often the only measurable effect.
Another advantage of personal selling is that a salesperson is in an excellent position to encourage the customer to act. The one-on-one interaction of personal selling means that a salesperson can effectively respond to and overcome objections—e.g., concerns or reservations about the product—so that the customer is more likely to buy. Salespeople can also offer many customized reasons that might spur a customer to buy, whereas an advertisement offers a limited set of reasons that may not persuade everyone in the target audience.
A final strength of personal selling is the multiple tasks that the sales force can perform. For example, in addition to selling, a salesperson can collect payments, service or repair products, return products, and collect product and marketing information. In fact, salespeople are often the best resources when it comes to disseminating positive word-of-mouth product information.
High cost is the primary disadvantage of personal selling. With increased competition, higher travel and lodging costs, and higher salaries, the cost per sales contract continues to rise. Many companies try to control sales costs by compensating sales representatives through commissions alone, thereby guaranteeing that salespeople are paid only if they generate sales. However, commission-only salespeople may become risk averse and only call on clients who have the highest potential return. These salespeople, then, may miss opportunities to develop a broad base of potential customers that could generate higher sales revenues in the long run.
Companies can also reduce sales costs by using complementary techniques, such as telemarketing, direct mail, toll-free numbers for interested customers, and online communication with qualified prospects. Telemarketing and online communication can further reduce costs by serving as an actual selling vehicle. Both technologies can deliver sales messages, respond to questions, take payment, and follow up.
A second disadvantage of personal selling is the problem of finding and retaining high-quality people. Experienced salespeople sometimes realize that the only way their income can outpace their cost-of-living increase is to change jobs. Also, because of the push for profitability, businesses try to hire experienced salespeople away from competitors rather than hiring college graduates, who take three to five years to reach the level of productivity of more experienced salespeople. These two staffing issues have caused high turnover in many sales forces.
Another weakness of personal selling is message inconsistency. Many salespeople view themselves as independent from the organization, so they design their own sales techniques, use their own message strategies, and engage in questionable ploys to generate sales. (You’ll recall our discussion in the ethics module about the unique challenges that B2B salespeople face.) As a result, it can be difficult to find a unified company or product message within a sales force or between the sales force and the rest of the marketing mix.
A final disadvantage of personal selling is that sales-force members have different levels of motivation. Salespeople may vary in their willingness to make the desired number of sales calls each day; to make service calls that do not lead directly to sales; or to take full advantage of the technologies available to them.
How IMC Supports Personal Selling [4]
As with any other marketing communication method, personal selling must be evaluated on the basis of its contribution to the overall marketing mix. The costs of personal selling can be high and carry risks, but the returns may be just as high. In addition, when personal selling is supported by other elements of a well-conceived IMC strategy, it can be very effective indeed.
Consider the following example of Audi, which set out to build a customer-relationship program:
Audi’s goal was to not have the relationship with the customer end after the sale was made. Operating on the assumption that the company’s best potential customers were also its existing customers, the company initiated an online program to maintain contact, while allowing its sales force to concentrate on selling. Based on its television campaign for the new A4 model, Audi offered a downloadable screensaver that frequently broadcasted updated news and information automatically to the consumers’ computers. After displaying the screensaver option on its Web site, Audi sent an email to owners and prospects offering them the opportunity to download it. More than 10,000 people took advantage of the offer. Audi then began to maintain a continuous dialog with the adopters by sending them newsletters and updates. Click-through rates ranged from 25 to 35 percent on various parts of the site—well exceeding the standard rates—and car sales were 25 percent higher than they were the previous year, even in a down economy. [5]
As a result of several coordinated communication methods (TV advertising, email, downloadable screensaver, newsletters, and product information) and presumably a well-designed customer relationship management (CRM) system, Audi helped its sales force be more effective (by freeing it up to focus on sales and by connecting it with more prospective customers), which, turn, meant higher profits.
- smallbusiness.chron.com/strategic-selling-techniques-15747.html ↵
- http://www.smetimes.in/smetimes/in-depth/2010/Sep/02/personal-selling-when-and-how500001.html ↵
- http://www.smetimes.in/smetimes/in-depth/2010/Sep/02/personal-selling-when-and-how500001.html ↵
- http://www.zabanga.us/marketing-communications/how-companies-integrate-personal-selling-into-the-imc-program.html ↵
- http://www.zabanga.us/marketing-communications/how-companies-integrate-personal-selling-into-the-imc-program.html ↵
Contributors and Attributions
- Revision and adaptation. Provided by : Lumen Learning. License : CC BY-SA: Attribution-ShareAlike
- Personal Selling, From Boundless Marketing. Provided by : Boundless. Located at : https://courses.lumenlearning.com/boundless-marketing/ . License : CC BY-SA: Attribution-ShareAlike
- Phone call. Provided by : CWCS Managed Hosting. Located at : www.flickr.com/photos/122969584@N07/13780153345/. License : CC BY: Attribution
- Communicating to Mass Markets, from Introducing Marketing. Authored by : John Burnett. Project : Global Text. License : CC BY: Attribution
- Handshake. Authored by : Cytonn Photography. Provided by : Unsplash. Located at : https://unsplash.com/photos/n95VMLxqM2I . License : CC0: No Rights Reserved . License Terms : Unsplash License | 2,410 | common-pile/libretexts_filtered | https://biz.libretexts.org/Bookshelves/Marketing/Principles_of_Marketing_(Lumen)/13%3A_Promotion-_Integrated_Marketing_Communication_(IMC)/13.08%3A_Reading-_Personal_Selling | libretexts | libretexts-0000.json.gz:5434 | https://biz.libretexts.org/Bookshelves/Marketing/Principles_of_Marketing_(Lumen)/13%3A_Promotion-_Integrated_Marketing_Communication_(IMC)/13.08%3A_Reading-_Personal_Selling |
agTR-nZoSocktqRc | 7.2B: Vitamin D | 7.2B: Vitamin D
Vitamin D refers to a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, iron, magnesium, phosphate, and zinc. In humans, the most important compounds in this group are vitamin D3 and vitamin D2. Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements. Very few foods contain vitamin D; synthesis of vitamin D in the skin is the major natural source of the vitamin and is dependent on sun exposure (specifically UVB radiation).
Deficiency: Rickets
A diet deficient in vitamin D in conjunction with inadequate sun exposure causes osteomalacia (or rickets when it occurs in children), which is a softening of the bones. In the developed world, this is a rare disease. However, vitamin D deficiency has become a worldwide problem in the elderly and remains common in children and adults. Low blood calcifediol (25-hydroxy-vitamin D) can result from avoiding the sun. Deficiency results in impaired bone mineralization and bone damage which leads to bone-softening diseases, including rickets and osteomalacia.
Legs in a 2 year old child with rickets. (CC BY-SA 1.0; Michael L. Richardson, M.D.).
Rickets, a childhood disease, is characterized by impeded growth and soft, weak, deformed long bones that bend and bow under their weight as children start to walk. This condition is characterized by bow legs,] which can be caused by calcium or phosphorus deficiency, as well as a lack of vitamin D; today, it is largely found in low-income countries in Africa, Asia, or the Middle East and in those with genetic disorders such as pseudovitamin D deficiency rickets. Maternal vitamin D deficiency may cause overt bone disease from before birth and impairment of bone quality after birth. Nutritional rickets exists in countries with intense year-round sunlight such as Nigeria and can occur without vitamin D deficiency.
Vitamin D deficiency remains the main cause of rickets among young infants in most countries, because breast milk is low in vitamin D and social customs and climatic conditions can prevent adequate sun exposure. In sunny countries such as Nigeria, South Africa, and Bangladesh, where the disease occurs among older toddlers and children, it has been attributed to low dietary calcium intakes, which are characteristic of cereal-based diets with limited access to dairy products.
Synthesis in the Skin
Vitamin D 3 is produced photochemically from 7-dehydrocholesterol in the skin of most vertebrate animals, including humans. The precursor of vitamin D 3 , 7-dehydrocholesterol is produced in relatively large quantities. 7-Dehydrocholesterol reacts with UVB light at wavelengths between 270 and 300 nm, with peak synthesis occurring between 295 and 297 nm. These wavelengths are present in sunlight, as well as in the light emitted by the UV lamps in tanning beds (which produce ultraviolet primarily in the UVA spectrum, but typically produce 4% to 10% of the total UV emissions as UVB). Exposure to light through windows is insufficient because glass almost completely blocks UVB light.
Adequate amounts of vitamin D can be produced with moderate sun exposure to the face, arms and legs, averaging 5–30 minutes twice per week, or approximately 25% of the time for minimal sunburn. The darker the skin, and the weaker the sunlight, the more minutes of exposure are needed. Vitamin D overdose is impossible from UV exposure; the skin reaches an equilibrium where the vitamin degrades as fast as it is created.
Dietary Reference Intakes (USA)
Accordingly, the Dietary Reference Intake for vitamin D assumes no synthesis occurs and all of a person's vitamin D is from food intake. As vitamin D is synthesized in adequate amounts by most mammals exposed to sunlight, it is not strictly a vitamin, and may be considered a hormone as its synthesis and activity occur in different locations. Vitamin D has a significant role in calcium homeostasis and metabolism. Its discovery was due to effort to find the dietary substance lacking in rickets.
Different institutions propose different recommendations concerning daily amounts of the vitamin.The recommended daily intake of vitamin D may not be sufficient if sunlight exposure is limited. According to the United States Institute of Medicine, the recommended dietary allowances (RDA) of vitamin D are (Conversion : 1 µg = 40 IU and 0.025 µg = 1 IU) :
| Age group | RDA (IU/day) |
|---|---|
| Infants 0–6 months | 400* |
| Infants 6–12 months | 400* |
| 1–70 years | 600 (15 μg/day) |
| 71+ years | 800 (20 μg/day) |
| Pregnant/Lactating | 600 (15 μg/day) |
- Asterisk for infants indicates adequate intake (AI) for infants, as an RDA has yet to be established for infants.
For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For vitamin D labeling purposes 100% of the Daily Value was 400 IU (10 μg), but as of May 2016 it has been revised to 800 IU (20 μg). A table of the pre-change adult Daily Values is provided at Reference Daily Intake. Food and supplement companies have until July 28, 2018 to comply with the change.
Contributors and Attributions
- Wikipedia | 1,105 | common-pile/libretexts_filtered | https://med.libretexts.org/Courses/Folsom_Lake_College/NUTRI_300%3A_Nutrition_(Giordano)/07%3A_Vitamins/7.2%3A_Fat_Soluble_Vitamins/7.2B%3A_Vitamin_D | libretexts | libretexts-0000.json.gz:891 | https://med.libretexts.org/Courses/Folsom_Lake_College/NUTRI_300%3A_Nutrition_(Giordano)/07%3A_Vitamins/7.2%3A_Fat_Soluble_Vitamins/7.2B%3A_Vitamin_D |
_SMfhydt07SZfDN2 | A Guide to Physical Activity | 20 3.4 Dietary Recommendations and Nutrition Labels
Dietary Guidelines and Key Recommendations
The 2015-2020 Dietary Guidelines for Americans recommend that individuals consume foods which are nutrient-dense from each of the major food groups. Foods that are high in calories (i.e., foods that provide a large amount of energy for the body), but low in nutritional value are referred to as “calorie-dense” foods. Conversely, foods that are high in nutrients (i.e., foods containing an abundance of vitamins or minerals) but are low in calories are referred to as “nutrient-dense.” The 2015-2020 Dietary Guidelines for Americans recommend that individuals consume foods which are nutrient-dense from each of the major food groups for optimal health (DeSalvo, Olson, & Casavale, 2016; Dietary Guidelines Advisory Committee, 2016; Millen, et al., 2016).
- Vegetables
- Grains
- Fruits
- Dairy
- Proteins
- Oils
The 2015-2020 Dietary Guidelines for Americans encourage individuals to make behavioral changes in their eating patterns by focusing on small, healthy dietary shifts or substitutions (such as choosing nutrient-dense foods and beverages in place of less healthy, calorie-dense options). The Dietary Guidelines claim that these healthy behavioral shifts may be achieved by following five overreaching Guidelines: (Dietary Guidelines Advisory Committee, 2016)
- Follow a healthy eating pattern across the lifespan.
All food and beverage choices matter. Choose a healthy eating pattern at an appropriate calorie level to help achieve and maintain a healthy body weight, support nutrient adequacy, and reduce the risk of chronic disease. - Focus on variety, nutrient density, and amount.
To meet nutrient needs within calorie limits, choose a variety of nutrient-dense foods across and within all food groups in recommended amounts. - Limit calories from added sugars and saturated fats and reduce sodium intake.
Develop an eating pattern low in added sugars (Note: added sugars are not naturally found in food, and have been added in the processing or preparation of food), saturated fats, and sodium. Cut back on foods and beverages higher in these components to amounts that fit within healthy eating patterns. - Shift to healthier food and beverage choices.
Choose nutrient-dense foods and beverages across and within all food groups in place of less healthy choices. Consider cultural and personal preferences to make these shifts easier to accomplish and maintain. - Support healthy eating patterns for all.
Everyone has a role in helping to create and support healthy eating patterns in multiple settings nationwide, from home to school to work to communities.
In addition to the aforementioned five Guidelines, the 2015-2020 Dietary Guidelines for Americans outlines several Key Recommendations for how an individual may maintain healthy eating behaviors throughout the lifetime (Dietary Guidelines Advisory Committee, 2016).
- Consume a healthy eating pattern that accounts for all foods and beverages within an appropriate calorie level.
- A healthy eating pattern includes: A variety of vegetables from all of the subgroups—dark green, red and orange, legumes (beans and peas), starchy, and other. Fruits, especially whole fruits. Grains, at least half of which are whole grains. Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages. A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products. Oils.
- A healthy eating pattern limits: Saturated fats and trans fats, added sugars, and sodium.
The Dietary Guidelines’ Key Recommendations place a quantitative limit on several components of the diet which have been linked to particular public health concerns in the United States. These specified limits are as follows: (Dietary Guidelines Advisory Committee, 2016)
- Consume less than 10 percent of calories per day from added sugars.
- Consume less than 10 percent of calories per day from saturated fats.
- Consume less than 2,300 milligrams (mg) per day of sodium.
- If alcohol is consumed, it should be consumed in moderation—up to one drink per day for women and up to two drinks per day for men—and only by adults of legal drinking age.
In conclusion, the Dietary Guidelines recommend that all individuals also strive to meet the Physical Activity Guidelines for Americans (described in Chapter 1) in order to maintain a healthy body weight, promote health, and prevent chronic disease (Dietary Guidelines Advisory Committee, 2016).
Comprehension check:
Calculating your intake of added sugars and saturated fats may be challenging if you do not know how many calories you have consumed during the day. If you are unsure of your total daily caloric intake, you may follow several simple rules for limiting sugars and fats in the diet. (1) Aim for less than 6 teaspoons or approximately 25 grams (a teaspoon contains approximately 4 grams) of sugar per day (2) Follow the American Heart Association recommendations, and limit your intake of saturated foods to less than 16 grams per day. Do you know where you may find this nutritional information? (Hint: check the Nutrition Facts Label on every food product).
Dietary Reference Intakes (DRIs), Percent Daily Value (DV), and Nutrition Facts Labels
Dietary Reference Intakes (DRIs) are nutrient-based reference values which are utilized in planning and assessing diet components. DRIs include a variety of nutritional standards, and assess adequacy of nutrient intake (Williams, 1999). DRIs do not inform individuals of what specific foods should be consumed.
Daily Values are recommended averages, and are based upon a 2,000 calorie per day diet.The Percent Daily Value (DV) is based upon several DRI values and can be found on nutrition labels. Daily Values are recommended averages, and are based upon a 2,000 calorie per day diet (Williams, 1999). Percent DV is for the entire day, not just one meal or snack. Some individuals may need more or less than 2,000 calories per day (e.g., varying physical activity levels), or may have special dietary requirements (e.g., high blood pressure, leading to potential recommendations from a physician or dietician to limit sodium further and increase intake of magnesium and potassium). Therefore, percent DV may need to be adjusted for the unique needs of the individual.
Nutrition Facts Labels include DV, serving size information, total calories per serving, and an ingredient list. Processed or packaged foods often require a Nutrition Facts label; however, several exemptions include foods manufactured by small businesses and restaurants, ready-to-eat items (such as bakery items), or foods which do not contain a significant amount of nutrients (such as coffee) (Williams, 1999). Recently, the United States Food and Drug Administration (FDA) developed a new design for the Nutrition Facts labels, based upon current scientific evidence linking components of the diet, such as added sugars or saturated fats, to chronic diseases such as obesity and heart disease (U.S. Food and Drug Administration, 2018). This new label is intended to assist consumers in making healthier nutritional choices. The prudent individual will carefully examine a Nutrition Facts label to assess if a particular food product fits into their healthy eating plan.
Comprehension check:
The new Nutrition Facts label is on the right below. Do you believe the changes to the label are effective in helping consumers make prudent nutritional choices? Why, or why not?
Works Cited
DeSalvo, K. B., Olson, R., & Casavale, K. O. (2016). Dietary guidelines for Americans. Jama, 315(5), 457-458.
Dietary Guidelines Advisory Committee. (2016). Dietary Guidelines for Americans 2015-2020. Government Printing Office.
Millen, B. E., Abrams, S., Adams-Campbell, L., Anderson, C. A., Brenna, J. T., Campbell, W. W., … & Perez-Escamilla, R. (2016). The 2015 dietary guidelines advisory committee scientific report: development and major conclusions. Advances in nutrition, 7(3), 438-444.
Williams, M. H. (1999). Nutrition for health, fitness and sport (No. Ed. 5). WCB/McGraw-Hill.
U.S. Food and Drug Administration (2018, January). The new and improved nutrition facts Label – key changes. Retrieved from https://www.fda.gov/files/food/published/The-New-and-Improved-Nutrition-Facts-Label-%E2%80%93-Key-Changes.pdf | 1,658 | common-pile/pressbooks_filtered | https://openpress.usask.ca/guidetophysicalactivity/chapter/3-4-dietary-recommendations-and-nutrition-labels/ | pressbooks | pressbooks-0000.json.gz:7962 | https://openpress.usask.ca/guidetophysicalactivity/chapter/3-4-dietary-recommendations-and-nutrition-labels/ |
T4dtutJqMaBrAuNT | 16: Extinction | 16: Extinction
| Era | Period | Epoch | Approximate Duration of Era, Period or Epoch (millions of years before present) | Major Extinction Evens |
|---|---|---|---|---|
| CENOZOIC | Quaternary | Holocene | present - 0.01 |
\(6^{th}\) major extinction ? \(5^{th}\) major extinction (end of Cretaceous; K-T boundary) \(4^{th}\) major extinction (end of Triassic) \(3^{th}\) major extinction (end of Permian) \(2^{nd}\) major extinction (Late Devonian) \(1^{st}\) major extinction (end of Ordovician) |
| Pleistocene | 0.01-1.6 | |||
| Tertiary | Pliocene | 1.6-5.3 | ||
| Miocene | 5.3-23 | |||
| Oligocene | 24-37 | |||
| Eocene | 37-58 | |||
| Paleocene | 58-65 | |||
| MESOZOIC | Cretaceous | 65-144 | ||
| Jurassic | 144-208 | |||
| Triassic | 208-245 | |||
| PALEOZOIC |
Permian |
245-286 | ||
|
(Carboniferous) Pennsylvanian |
286-325 | |||
| (Carboniferous) Mississippian | 325-360 | |||
| Devonian | 360-408 | |||
| Silurian | 408-440 | |||
| Ordovician | 440-505 | |||
| Cambrian | 505-570 | |||
| PRECAMBRIAN | 570-4500 |
Each of the first five mass extinctions shown in Table \(\PageIndex{1}\) represents a significant loss of biodiversity - but recovery has been good on a geologic time scale. Mass extinctions are apparently followed by a sudden burst of evolutionary diversification on the part of the remaining species, presumably because the surviving species started using habitats and resources that were previously "occupied" by more competitively successful species that went extinct. However, this does not mean that the recoveries from mass extinction have been rapid; they have usually required some tens of millions of years (Jablonski, 1995).
It is hypothesized that we are currently on the brink of a "sixth mass extinction," but one that differs from previous events. The five other mass extinctions predated humans and were probably the ultimate products of some physical process (e.g. climate change through meteor impacts), rather than the direct consequence of the action of some other species. In contrast, the sixth mass extinction is the product of human activity over the last several hundred, or even several thousand years. These mass extinctions, and their historic and modern consequences are discussed in more detail in the modules on Historical perspectives on extinction and the current biodiversity crisis, and Ecological consequences of extinctions..
Glossary
- Extinct
- a species is assumed to be extinct when there is no reasonable doubt that the last individual has died (IUCN, 2002)
- Extinction
- the complete disappearance of a species from Earth
- Mass extinction
- a period when there is a sudden increase in the rate of extinction, such that the rate at least doubles, and the extinctions include representatives from many different taxonomic groups of plants and animals | 601 | common-pile/libretexts_filtered | https://bio.libretexts.org/Bookshelves/Ecology/Biodiversity_(Bynum)/16%3A_Extinction | libretexts | libretexts-0000.json.gz:26988 | https://bio.libretexts.org/Bookshelves/Ecology/Biodiversity_(Bynum)/16%3A_Extinction |
wt79XWFwrOgc4OWB | Introduction to Machining | 6.5 Choosing a machine
Tim A. Bacon
A machine will be selected for its ability to efficiently remove material, and its ability to repeatedly achieve a consistent tolerance. When “roughing out a part,” the majority of material will be removed in the most productive manner possible. To illustrate, grinders are designed to remove around .01 inch of material at the most. This would not be a good machine choice if .5 inches of material needed to be removed. A hobbyist might enjoy just the process of removing material without consideration of timeliness. A paid machinist, however, needs to attend to time being careful to work within project deadlines.
Referencing the picture of the bench block in Section 6.0, you’ll note that it is round. The outside shape of the part being made is called the profile of the part. The sample bench block we are creating is made of 1018 mild steel. This material comes in a flat bar that is band sawed into smaller squares so the machinist can more easily handle the part during production and the material isn’t wasted. If the outside of the profile is cut first, it will be more difficult to hold on to because a circle requires special tooling for workholding. This means if you immediately start cutting a circle out of your material, you will create more work, and the part will take more time to produce. From what we see of the bench block, the vertical mill is the best tool for this project. Again, job planning that includes tool choice leads to greater efficiency. And, efficiency equals profitability.
Machine capability is the level of accuracy a machine provides without user influence. Machine capability varies from one machine to the next. A band saw might be used for the first step in cutting a block of material to +/- .06. But, if the requirements are +/- .01, a table saw might be a better choice because it offers greater accuracy. In making these decisions, machinists need to consider machine capability. When deciding on the machine to use, consider the tolerance requirements and identify a machine that is capable of achieving those results. When machine capability is aligned with technical requirements, productivity increases.
In addition to machine capability, a profitable operation will factor in material usage and conservation. For large quantity jobs, the project plan should include optimization strategies. These strategies are identified after the steps are outlined.
Making 100 of the same part is different from a single part. When the number of parts increases, repeatability and reliability need to be considered. The plan may also shift to one that has batch processing, where a small number of features are cut on all parts before continuing to the next step. This approach is instead of making a complete part before making the next one.
Choosing the right machine for the job requires a comprehensive understanding of the machining process, materials used, tooling, equipment, and the ability to comprehend technical drawings accurately. By meticulously planning each stage of the machining process, potential risks and challenges can be anticipated. This will help to improve productivity, efficiency, and overall success.
A surface grinder can achieve an almost mirror finish with tolerances less than the thickness of a piece of paper (.003). A band saw, mentioned earlier in this book, can cut parts to within 1/16th, or .0625 (spoken as sixty-two and a half thousandths).
We will create a project plan for the bench block to be made with manual machines because we are only making one. If we had to make 100, we might want to automate the process by using CNC machines.
Choosing a CNC mill over manual machines is based on the need for large quantities, high precision, and repetitive actions. Typically, when bidding on jobs, the greater the technology of the equipment, the higher the cost to the customer. If the part can be made by manual machines, the cost to the customer could be $150 per hour. If a CNC mill is used, the customer might be charged $500 per hour. Machines that have automation or are controlled by computers are capable of running more efficiently with higher, more consistent accuracy and this costs more.
Outside processes, sometimes referred to as secondary operations, are a consideration when planning. A machinist might need to leave a part partially finished awaiting secondary operations. In this case, material is purposely left on to be removed later. The part is then sent out for heat treating to improve the characteristics of the material, such as hardness. Upon returning to the shop, the rest of the material is removed. Some other secondary operations are painting, anodizing, and polishing.
Attributions
- Figure 6.10: Vertical bandsaw by T Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 6.11: Horizontal bandsaw by T Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 6.12: Horizontal surface Grinder by T Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 6.13: Vertical CNC milling machine by T Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0 | 1,137 | common-pile/pressbooks_filtered | https://openwa.pressbooks.pub/intromachining1/chapter/wa6-5/ | pressbooks | pressbooks-0000.json.gz:46241 | https://openwa.pressbooks.pub/intromachining1/chapter/wa6-5/ |
OU6cLCrLd_vNXjMe | 13.7.6: Properties of Real Numbers | 13.7.6: Properties of Real Numbers
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Learning Objectives
By the end of this section, you will be able to:
- Use the commutative and associative properties
- Use the properties of identity, inverse, and zero
- Simplify expressions using the Distributive Property
Use the Commutative and Associative Properties
The order we add two numbers doesn’t affect the result. If we add \(8+9\) or \(9+8\), the results are the same—they both equal 17. So, \(8+9=9+8\). The order in which we add does not matter!
Similarly, when multiplying two numbers, the order does not affect the result. If we multiply \(9·8\) or \(8·9\) the results are the same—they both equal 72. So, \(9·8=8·9\). The order in which we multiply does not matter! These examples illustrate the Commutative Property .
COMMUTATIVE PROPERTY
\[\begin{array}{lll} \textbf{of Addition} & \text{If }a \text{ and }b \text{are real numbers, then} & a+b=b+a. \\ \textbf{of Multiplication} & \text{If }a \text{ and }b \text{are real numbers, then} & a·b=b·a. \end{array} \]
When adding or multiplying, changing the order gives the same result.
The Commutative Property has to do with order. We subtract \(9−8\) and \(8−9\), and see that \(9−8\neq 8−9\). Since changing the order of the subtraction does not give the same result, we know that subtraction is not commutative .
Division is not commutative either . Since \(12÷3\neq 3÷12\), changing the order of the division did not give the same result. The commutative properties apply only to addition and multiplication!
- Addition and multiplication are commutative.
- Subtraction and division are not commutative.
When adding three numbers, changing the grouping of the numbers gives the same result. For example,\((7+8)+2=7+(8+2)\), since each side of the equation equals 17.
This is true for multiplication, too. For example, \(\left(5·\frac{1}{3}\right)·3=5·\left(\frac{1}{3}·3\right)\), since each side of the equation equals 5.
These examples illustrate the Associative Property .
ASSOCIATIVE PROPERTY
\[\begin{array}{lll} \textbf{of Addition} & \text{If }a,b, \text{ and }c \text{ are real numbers, then} & (a+b)+c=a+(b+c). \\ \textbf{of Multiplication} & \text{If }a,b,\text{ and }c \text{ are real numbers, then} & (a·b)·c=a·(b·c). \end{array} \]
When adding or multiplying, changing the grouping gives the same result.
The Associative Property has to do with grouping. If we change how the numbers are grouped, the result will be the same. Notice it is the same three numbers in the same order—the only difference is the grouping.
We saw that subtraction and division were not commutative. They are not associative either.
\[\begin{array}{cc} (10−3)−2\neq 10−(3−2) & (24÷4)÷2\neq 24÷(4÷2) \\ 7−2\neq 10−1 & 6÷2\neq 24÷2 \\ 5\neq 9 & 3\neq 12 \end{array}\]
When simplifying an expression, it is always a good idea to plan what the steps will be. In order to combine like terms in the next example, we will use the Commutative Property of addition to write the like terms together.
Example \(\PageIndex{1}\)
Simplify: \(18p+6q+15p+5q\).
- Answer
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\[\begin{array}{lc} \text{} & 18p+6q+15p+5q \\ \text{Use the Commutative Property of addition to} & 18p+15p+6q+5q \\ \text{reorder so that like terms are together.} & {} \\ \text{Add like terms.} & 33p+11q \end{array}\]
Example \(\PageIndex{2}\)
Simplify: \(23r+14s+9r+15s\).
- Answer
-
\(32r+29s\)
Example \(\PageIndex{3}\)
Simplify: \(37m+21n+4m−15n\).
- Answer
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\(41m+6n\)
When we have to simplify algebraic expressions, we can often make the work easier by applying the Commutative Property or Associative Property first.
EXAMPLE \(\PageIndex{4}\)
Simplify: \((\frac{5}{13}+\frac{3}{4})+\frac{1}{4}\).
- Answer
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\( \begin{array}{lc} \text{} & (\frac{5}{13}+\frac{3}{4})+\frac{1}{4} \\ {\text{Notice that the last 2 terms have a common} \\ \text{denominator, so change the grouping.} } & \frac{5}{13}+(\frac{3}{4}+\frac{1}{4}) \\ \text{Add in parentheses first.} & \frac{5}{13}+(\frac{4}{4}) \\ \text{Simplify the fraction.} & \frac{5}{13}+1 \\ \text{Add.} & 1\frac{5}{13} \\ \text{Convert to an improper fraction.} & \frac{18}{13} \end{array}\)
EXAMPLE \(\PageIndex{5}\)
Simplify: \((\frac{7}{15}+\frac{5}{8})+\frac{3}{8}.\)
- Answer
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\(1 \frac{7}{15}\)
EXAMPLE \(\PageIndex{6}\)
Simplify: \((\frac{2}{9}+\frac{7}{12})+\frac{5}{12}\).
- Answer
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\(1\frac{2}{9}\)
Use the Properties of Identity, Inverse, and Zero
What happens when we add 0 to any number? Adding 0 doesn’t change the value. For this reason, we call 0 the additive identity . The Identity Property of Addition that states that for any real number \(a,a+0=a\) and \(0+a=a.\)
What happens when we multiply any number by one? Multiplying by 1 doesn’t change the value. So we call 1 the multiplicative identity. The Identity Property of Multiplication that states that for any real number \(a,a·1=a\) and \(1⋅a=a.\)
We summarize the Identity Properties here.
IDENTITY PROPERTY
\[\begin{array}{ll} \textbf{of Addition} \text{ For any real number }a:a+0=a & 0+a=a \\ \\ \\ \textbf{0} \text{ is the } \textbf{additive identity} \\ \textbf{of Multiplication} \text{ For any real number } a:a·1=a & 1·a=a \\ \\ \\ \textbf{1} \text{ is the } \textbf{multiplicative identity} \end{array}\]
What number added to 5 gives the additive identity, 0? We know
The missing number was the opposite of the number!
We call \(−a\) the additive inverse of \(a\). The opposite of a number is its additive inverse. A number and its opposite add to zero, which is the additive identity. This leads to the Inverse Property of Addition that states for any real number \(a,a+(−a)=0.\)
What number multiplied by \(\frac{2}{3}\) gives the multiplicative identity, 1? In other words, \(\frac{2}{3}\) times what results in 1? We know
The missing number was the reciprocal of the number!
We call \(\frac{1}{a}\) the multiplicative inverse of a . The reciprocal of a number is its multiplicative inverse. This leads to the Inverse Property of Multiplication that states that for any real number \(a,a\neq 0,a·\frac{1}{a}=1.\)
We’ll formally state the inverse properties here.
INVERSE PROPERTY
\[\begin{array}{lc} \textbf{of addition} \text{For any real number }a, & a+(−a)=0 \\ \;\;\;\; −a \text{ is the } \textbf{additive inverse }\text{ of }a & {} \\ \;\;\;\; \text{A number and its } \textit{opposite } \text{add to zero.} \\ \\ \\ \textbf{of multiplication } \text{For any real number }a,a\neq 0 & a·\dfrac{1}{a}=1 \\ \;\;\;\;\;\dfrac{1}{a} \text{ is the } \textbf{multiplicative inverse} \text{ of }a \\ \;\;\;\; \text{A number and its } \textit{reciprocal} \text{ multiply to one.} \end{array}\]
The Identity Property of addition says that when we add 0 to any number, the result is that same number. What happens when we multiply a number by 0? Multiplying by 0 makes the product equal zero.
What about division involving zero? What is \(0÷3\)? Think about a real example: If there are no cookies in the cookie jar and 3 people are to share them, how many cookies does each person get? There are no cookies to share, so each person gets 0 cookies. So, \(0÷3=0.\)
We can check division with the related multiplication fact. So we know \(0÷3=0\) because \(0·3=0\).
Now think about dividing by zero. What is the result of dividing 4 by 0? Think about the related multiplication fact:
Is there a number that multiplied by 0 gives 4? Since any real number multiplied by 0 gives 0, there is no real number that can be multiplied by 0 to obtain 4. We conclude that there is no answer to \(4÷0\) and so we say that division by 0 is undefined .
We summarize the properties of zero here.
PROPERTIES OF ZERO
Multiplication by Zero: For any real number a ,
\[a⋅0=0 \; \; \; 0⋅a=0 \; \; \; \; \text{The product of any number and 0 is 0.}\]
Division by Zero: For any real number a , \(a\neq 0\)
\[\begin{array}{cl} \dfrac{0}{a}=0 & \text{Zero divided by any real number, except itself, is zero.} \\ \dfrac{a}{0} \text{ is undefined} & \text{Division by zero is undefined.} \end{array}\]
We will now practice using the properties of identities, inverses, and zero to simplify expressions.
EXAMPLE \(\PageIndex{7}\)
Simplify: \(−84n+(−73n)+84n.\)
- Answer
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\(\begin{array}{lc} \text{} & −84n+(−73n)+84n \\ \text{Notice that the first and third terms are} \\ \text{opposites; use the Commutative Property of} & −84n+84n+(−73n) \\ \text{addition to re-order the terms.} \\ \text{Add left to right.} & 0+(−73n) \\ \text{Add.} & −73n \end{array}\)
EXAMPLE \(\PageIndex{8}\)
Simplify: \(−27a+(−48a)+27a\).
- Answer
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\(−48a\)
EXAMPLE \(\PageIndex{9}\)
Simplify: \(39x+(−92x)+(−39x)\).
- Answer
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\(−92x\)
Now we will see how recognizing reciprocals is helpful. Before multiplying left to right, look for reciprocals—their product is 1.
EXAMPLE \(\PageIndex{10}\)
Simplify: \(\frac{7}{15}⋅\frac{8}{23}⋅\frac{15}{7}\).
- Answer
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\(\begin{array}{lc} \text{} & \frac{7}{15}⋅\frac{8}{23}⋅\frac{15}{7} \\ \text{Notice the first and third terms} \\ {\text{are reciprocals, so use the Commutative} \\ \text{Property of multiplication to re-order the} \\ \text{factors.}} & \frac{7}{15}·\frac{15}{7}·\frac{8}{23} \\ \text{Multiply left to right.} & 1·\frac{8}{23} \\ \text{Multiply.} & \frac{8}{23} \end{array}\)
EXAMPLE \(\PageIndex{11}\)
Simplify: \(\frac{9}{16}⋅\frac{5}{49}⋅\frac{16}{9}\).
- Answer
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\(\frac{5}{49}\)
Simplify: \(\frac{6}{17}⋅\frac{11}{25}⋅\frac{17}{6}\).
- Answer
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\(\frac{11}{25}\)
The next example makes us aware of the distinction between dividing 0 by some number or some number being divided by 0.
Simplify: a. \(\frac{0}{n+5}\), where \(n\neq −5\) b. \(\frac{10−3p}{0}\) where \(10−3p\neq 0.\)
- Answer
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a.
\(\begin{array}{lc} {} & \dfrac{0}{n+5} \\ \text{Zero divided by any real number except itself is 0.} & 0 \end{array}\)
b.
\(\begin{array}{lc} {} & \dfrac{10−3p}{0} \\ \text{Division by 0 is undefined.} & \text{undefined} \end{array}\)
EXAMPLE \(\PageIndex{14}\)
Simplify: a. \(\frac{0}{m+7}\), where \(m\neq −7\) b. \(\frac{18−6c}{0}\), where \(18−6c\neq 0\).
- Answer
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a. 0
b. undefined
EXAMPLE \(\PageIndex{15}\)
Simplify: a. \(\frac{0}{d−4}\), where \(d\neq 4\) b. \(\frac{15−4q}{0}\), where \(15−4q\neq 0\).
- Answer
-
a. 0
b. undefined
Simplify Expressions Using the Distributive Property
Suppose that three friends are going to the movies. They each need $9.25—that’s 9 dollars and 1 quarter—to pay for their tickets. How much money do they need all together?
You can think about the dollars separately from the quarters. They need 3 times $9 so $27 and 3 times 1 quarter, so 75 cents. In total, they need $27.75. If you think about doing the math in this way, you are using the Distributive Property.
DISTRIBUTIVE PROPERTY
\(\begin{array}{lc} \text{If }a,b \text{,and }c \text{are real numbers, then} \; \; \; \; \; & a(b+c)=ab+ac \\ {} & (b+c)a=ba+ca \\ {} & a(b−c)=ab−ac \\{} & (b−c)a=ba−ca \end{array}\)
In algebra, we use the Distributive Property to remove parentheses as we simplify expressions.
EXAMPLE \(\PageIndex{16}\)
Simplify: \(3(x+4)\).
- Answer
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\(\begin{array} {} & 3(x+4) \\ \text{Distribute.} \; \; \; \; \; \; \; \; & 3·x+3·4 \\ \text{Multiply.} & 3x+12 \end{array}\)
Simplify: \(4(x+2)\).
- Answer
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\(4x8\)
EXAMPLE \(\PageIndex{18}\)
Simplify: \(6(x+7)\).
- Answer
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\(6x42\)
Some students find it helpful to draw in arrows to remind them how to use the Distributive Property. Then the first step in Example would look like this:
EXAMPLE \(\PageIndex{19}\)
Simplify: \(8(\frac{3}{8}x+\frac{1}{4})\).
- Answer
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Distribute. Multiply.
EXAMPLE \(\PageIndex{20}\)
Simplify: \(6(\frac{5}{6}y+\frac{1}{2})\).
- Answer
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\(5y+3\)
EXAMPLE \(\PageIndex{21}\)
Simplify: \(12(\frac{1}{3}n+\frac{3}{4})\)
- Answer
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\(4n+9\)
Using the Distributive Property as shown in the next example will be very useful when we solve money applications in later chapters.
EXAMPLE \(\PageIndex{22}\)
Simplify: \(100(0.3+0.25q)\).
- Answer
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Distribute. Multiply.
EXAMPLE \(\PageIndex{23}\)
Simplify: \(100(0.7+0.15p).\)
- Answer
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\(70+15p\)
EXAMPLE \(\PageIndex{24}\)
Simplify: \(100(0.04+0.35d)\).
- Answer
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\(4+35d\)
When we distribute a negative number, we need to be extra careful to get the signs correct!
EXAMPLE \(\PageIndex{25}\)
Simplify: \(−11(4−3a).\)
- Answer
-
\(\begin{array}{lc} {} & −11(4−3a) \\ \text{Distribute. } \; \; \; \; \; \; \; \; \; \;& −11·4−(−11)·3a \\ \text{Multiply.} & −44−(−33a) \\ \text{Simplify.} & −44+33a \end{array}\)
Notice that you could also write the result as \(33a−44.\) Do you know why?
Simplify: \(−5(2−3a)\).
- Answer
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\(−10+15a\)
EXAMPLE \(\PageIndex{27}\)
Simplify: \(−7(8−15y).\)
- Answer
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\(−56+105y\)
In the next example, we will show how to use the Distributive Property to find the opposite of an expression.
Simplify: \(−(y+5)\).
- Answer
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\(\begin{array}{lc} {} & −(y+5) \\ \text{Multiplying by }−1 \text{ results in the opposite.}& −1(y+5) \\ \text{Distribute.} & −1·y+(−1)·5 \\ \text{Simplify.} & −y+(−5) \\ \text{Simplify.} & −y−5 \end{array} \)
EXAMPLE \(\PageIndex{29}\)
Simplify: \(−(z−11)\).
- Answer
-
\(−z+11\)
EXAMPLE \(\PageIndex{30}\)
Simplify: \(−(x−4)\).
- Answer
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\(−x+4\)
There will be times when we’ll need to use the Distributive Property as part of the order of operations. Start by looking at the parentheses. If the expression inside the parentheses cannot be simplified, the next step would be multiply using the Distributive Property, which removes the parentheses. The next two examples will illustrate this.
EXAMPLE \(\PageIndex{31}\)
Simplify: \(8−2(x+3)\)
- Answer
-
We follow the order of operations. Multiplication comes before subtraction, so we will distribute the 2 first and then subtract.
\(\begin{array}{lc} {} & \text{8−2(x+3)} \\ \text{Distribute.} & 8−2·x−2·3 \\ \text{Multiply.} & 8−2x−6 \\ \text{Combine like terms.} &−2x+2 \end{array}\)
EXAMPLE \(\PageIndex{32}\)
Simplify: \(9−3(x+2)\).
- Answer
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\(3−3x\)
EXAMPLE \(\PageIndex{33}\)
Simplify: \(7x−5(x+4)\).
- Answer
-
\(2x−20\)
EXAMPLE \(\PageIndex{34}\)
Simplify: \(4(x−8)−(x+3)\).
- Answer
-
\(\begin{array}{lc} {} & 4(x−8)−(x+3) \\ \text{Distribute.} & 4x−32−x−3 \\ \text{Combine like terms.} & 3x−35 \end{array}\)
EXAMPLE \(\PageIndex{35}\)
Simplify: \(6(x−9)−(x+12)\).
- Answer
-
\(5x−66\)
EXAMPLE \(\PageIndex{36}\)
Simplify: \(8(x−1)−(x+5)\).
- Answer
-
\(7x−13\)
All the properties of real numbers we have used in this chapter are summarized here.
|
Commutative Property
When adding or multiplying, changing the order gives the same result \[\begin{array}{lll} \textbf{of Addition} & \text{If }a \text{ and }b \text{are real numbers, then} & a+b=b+a. \\ \textbf{of Multiplication} & \text{If }a \text{ and }b \text{are real numbers, then} & a·b=b·a. \end{array} \] |
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Associative Property
When adding or multiplying, changing the grouping gives the same result. \[\begin{array}{lll} \textbf{of Addition} & \text{If }a,b, \text{ and }c \text{ are real numbers, then} & (a+b)+c=a+(b+c). \\ \textbf{of Multiplication} & \text{If }a,b,\text{ and }c \text{ are real numbers, then} & (a·b)·c=a·(b·c). \end{array} \] |
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Distributive Property
\[\begin{array}{lc} \text{If }a,b \text{,and }c \text{are real numbers, then} \; \; \; \; \; & a(b+c)=ab+ac \\ {} & (b+c)a=ba+ca \\ {} & a(b−c)=ab−ac \\{} & (b−c)a=ba−ca \end{array}\] |
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Identity Property
\[\begin{array}{ll} \textbf{of Addition} \text{ For any real number }a:a+0=a & 0+a=a \\ \;\;\;\; \textbf{0} \text{ is the } \textbf{additive identity} \\ \textbf{of Multiplication} \text{ For any real number } a:a·1=a & 1·a=a \\ \;\;\;\; \textbf{1} \text{ is the } \textbf{multiplicative identity} \end{array}\] |
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Inverse Property
\[\begin{array}{lc} \textbf{of addition } \text{For any real number }a, & a+(−a)=0 \\ \;\;\;\; −a \text{ is the } \textbf{additive inverse }\text{ of }a & {} \\ \;\;\;\; \text{A number and its } \textit{opposite } \text{add to zero.} \\ \\ \\ \textbf{of multiplication } \text{For any real number }a,a\neq 0 & a·\dfrac{1}{a}=1 \\ \;\;\;\;\;\dfrac{1}{a} \text{ is the } \textbf{multiplicative inverse} \text{ of }a \\ \;\;\;\; \text{A number and its } \textit{reciprocal} \text{ multiply to one.} \end{array}\] |
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Properties of Zero
\[\begin{array}{lc} \text{For any real number }a, & a·0=0 \\ {} & 0·a=0 \\ \text{For any real number }a,a\neq 0, & \dfrac{0}{a}=0 \\ \text{For any real number }a, & \dfrac{a}{0} \text{ is undefined} \end{array}\] |
Key Concepts
|
Commutative Property
When adding or multiplying, changing the order gives the same result \[\begin{array}{lll} \textbf{of Addition} & \text{If }a \text{ and }b \text{are real numbers, then} & a+b=b+a. \\ \textbf{of Multiplication} & \text{If }a \text{ and }b \text{are real numbers, then} & a·b=b·a. \end{array} \] |
| Associative Property When adding or multiplying, changing the grouping gives the same result. \[\begin{array}{lll} \textbf{of Addition} & \text{If }a,b, \text{ and }c \text{ are real numbers, then} & (a+b)+c=a+(b+c). \\ \textbf{of Multiplication} & \text{If }a,b,\text{ and }c \text{ are real numbers, then} & (a·b)·c=a·(b·c). \end{array} \] |
|
Distributive Property
\[\begin{array}{lc} \text{If }a,b \text{,and }c \text{are real numbers, then} \; \; \; \; \; & a(b+c)=ab+ac \\ {} & (b+c)a=ba+ca \\ {} & a(b−c)=ab−ac \\{} & (b−c)a=ba−ca \end{array}\] |
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Identity Property
\[\begin{array}{ll} \textbf{of Addition} \text{ For any real number }a:a+0=a & 0+a=a \\ \;\;\;\; \textbf{0} \text{ is the } \textbf{additive identity} \\ \textbf{of Multiplication} \text{ For any real number } a:a·1=a & 1·a=a \\ \;\;\;\; \textbf{1} \text{ is the } \textbf{multiplicative identity} \end{array}\] |
|
Inverse Property
\[\begin{array}{lc} \textbf{of addition} \text{For any real number }a, & a+(−a)=0 \\ \;\;\;\; −a \text{ is the } \textbf{additive inverse }\text{ of }a & {} \\ \;\;\;\; \text{A number and its } \textit{opposite } \text{add to zero.} \\ \\ \\ \textbf{of multiplication } \text{For any real number }a,a\neq 0 & a·\dfrac{1}{a}=1 \\ \;\;\;\;\;\dfrac{1}{a} \text{ is the } \textbf{multiplicative inverse} \text{ of }a \\ \;\;\;\; \text{A number and its } \textit{reciprocal} \text{ multiply to one.} \end{array}\] |
|
Properties of Zero
\[\begin{array}{lc} \text{For any real number }a, & a·0=0 \\ {} & 0·a=0 \\ \text{For any real number }a,a\neq 0, & \dfrac{0}{a}=0 \\ \text{For any real number }a, & \dfrac{a}{0} \text{ is undefined} \end{array}\] |
Glossary
- additive identity
- The number 0 is the additive identity because adding 0 to any number does not change its value.
- additive inverse
- The opposite of a number is its additive inverse.
- multiplicative identity
- The number 1 is the multiplicative identity because multiplying 1 by any number does not change its value.
- multiplicative inverse
- The reciprocal of a number is its multiplicative inverse. | 3,542 | common-pile/libretexts_filtered | https://math.libretexts.org/Courses/Las_Positas_College/Foundational_Mathematics/13%3A_Additional_Foundational_Content/13.07%3A_Foundations/13.7.06%3A_Properties_of_Real_Numbers | libretexts | libretexts-0000.json.gz:38542 | https://math.libretexts.org/Courses/Las_Positas_College/Foundational_Mathematics/13%3A_Additional_Foundational_Content/13.07%3A_Foundations/13.7.06%3A_Properties_of_Real_Numbers |
Jia6beS4ycqSGmUa | AI for Teachers: an Open Textbook | Additional Content
X5GON
Searching for educational resources is important for teachers, especially when preparing a new lecture, exploring a new field or subject, or preparing an activity. This material (courseware) can be just for documentation, but sometimes the teacher might want to build new courseware from it. It is tempting and intellectually legitimate to not reinvent the wheel and to use an intelligent form of copy-paste. Of course this is often not legal, as it breaks copyright laws.
When the authors of the resources licence their work with Creative Common licences, the resources become Open Educational Resources and the teacher can reuse, transform, remix and redistribute them freely. The only obligation, usually, is to quote the original author correctly. It is therefore important to identify when a resource is open or not.
There are some collections and repositories of well-licenced open educational resources and your ministry probably has one. But what about finding these resources anywhere on the web? Can we make use of a specific search engine for this?
Project X5-GON was funded by the European Union to find and index OER, to use artificial intelligence to curate these OER and propose AI tools, typically search tools, allowing users to better find OER.
Where does the AI appear in such a process?
It will appear in all stages:
During the ingestion stage, robots will scrap the web and return OER: this is a complex process as it means recognizing the OER and therefore the licences. Part of it can be seen as a typical classification task (a common AI task).
When the robot has found a resource, the text from this resource has to be recovered. When the resource is an audio or a video file, this means using transcription.
The 5 in X5-GON refers to the 5 barriers or dimensions the project wished to address: one of these being language. So, the next step of the process is to use automatic translation tools to obtain text versions in each of the chosen languages. Again a typical AI tool.
At this point you may wonder: automatic transcription and translation are fast-growing technologies. But they still make serious mistakes. Isn’t it dangerous to rely on these? The answer is that search and recommendation algorithms don’t need the exact text. They need to position the document in a space, next to keywords and other documents.
Think about a box full of old papers that you need to organise. Ideally you would want to have a preset organisation, and file each paper in the right place. But we usually don’t have this pre-existing filing system, and end up putting the papers close to each other when they have things in common, with unwritten rules of all sorts. These two papers go together because they are from the same year, these two because they are related to cars, these two because they’re the same size, and so forth. The key term here is “next to”. We will discuss this later in the book.
Once Once raw texts have been extracted, models can be built. Documents will become vectors in some high dimensional space, and comparing vectors will allow us to answer questions, such as: which ten documents are most similar to this one? Which five documents best match this keyword?
Richer models can be obtained through training. They can answer more complex questions:
- How difficult is this course? The answer can perhaps be somewhere in the course description, or in the meta-data. This is data that’s hidden from the viewer but which are supposed to give information about a document. More likely, they can be obtained through automatically analysing the document. The lengths of sentences and words, and the words themselves, are strong indicators of the age for which a course was intended.
- Should I look at this courseware before this other one? This is the prequel to be able to have a full course built automatically from given courseware.
What is the quality of the course? This is a difficult question for AI to answer. By attempting to answer it, AI could do more harm than good. Nevertheless, being able to find out if the facts in a course are correct makes sense. After fake news, will we have fake courses?
Some links
X5-Discover (https://discovery.x5gon.org/) is a search engine.
The learning platform X5-Learn (http://x5learn.org/) allows to choose one’s courseware and get the AI to organize it in the best order. In this case, a recommendation engine is used.
More X5-GON tools (an API for developers, a version to be installed in Moodle) can be found here.
The X5GON project was funded by the European Union’s Horizon 2020 research and innovation program grant number 761758. | 1,019 | common-pile/pressbooks_filtered | https://pressbooks.pub/aiforteachers/chapter/x5gon/ | pressbooks | pressbooks-0000.json.gz:32345 | https://pressbooks.pub/aiforteachers/chapter/x5gon/ |
XgYHVq6fLQRr_PuB | Foundations of Education | 69 Feedback Qualitative-Quantitative
When should qualitative or quantitative assessments be used?
| “ | Not everything that counts can be counted, and not everything that can be counted counts. | ” |
|
—Albert Einstein |
“Test day,” to most students, means studying, reviewing, and perhaps a bit of cramming to remember as much as possible. But to a teacher, a test gathers important information – does the student really get what I’ve been trying to teach him for the past few weeks? Standardized tests, a big issue in modern education, are certainly not the only kind of test teachers use, and tests aren’t the only way teachers can assess what students have learned. But years before No Child Left Behind, educational researchers at the University of Utah predicted that American educators were going to be “increasingly required to provide evidence” that students are learning what they are supposed to learn. Consequently, teachers now and in the future will have to figure out how to measure whether students have learned the material or not – and just how much of it they’ve learned (Worthen, Borg, and White 1993). Out of this challenge have come many ways to study, classify, and apply different kinds of educational assessment.
Quantitative Assessment
Countless books and articles have been written on the subject of educational measurement, but one way in particular to classify methods of assessment is to categorize them as either quantitative or qualitative.
Quantitative assessment, as the name suggests, focuses on numbers, or quantities. Usually, something that is quantitative can be measured and expressed in units (Wikipedia 2007). For instance, a quantitative test might include multiple-choice questions or fill-in-the-blank questions – these types of questions can easily be classified as “right” or “wrong” and the results tallied to produce a grade. Each right or wrong answer is a unit, and the group of units makes a number that is supposed to show whether or not the student knows the material.
For example:
- Solve 5x + 4 = 24
- What is the name of the capital city of France? (Satterly 1984)
Quantitative tests, like multiple-choice or fill-in-the-blank, are often seen as merely encouraging rote memorization – and they often do. For instance, asking a student, “Which part of speech is used to describe a noun?” from a list of four choices does not necessarily require the student to fully understand adjectives and how to use them. On the other hand, well-constructed questions can measure learning on a variety of levels on Bloom’s Taxonomy, including application and synthesis, if they ask the student to do high-level thinking in order to come up with the best answer (Satterly 1989). A teacher might give the student a sentence and ask him to choose the word that functions as an adjective – giving him the opportunity to apply what he knows to a new situation (Bloom 1984?).
Qualitative Assessment
Qualitative assessment, on the other hand, is not based on numbers or units, but on observations that often can be subjective. Many kinds of essay questions (those asking for things like the student’s opinion on a controversial issue, an analysis of a situation, or a free-response interpretation of a literary work) are examples of qualitative assessments. Though essay tests are often graded on a scale of points, based on criteria, the teacher still has a lot of leeway in deciding what constitutes an acceptable response.
Uses for both types in the classroom
While either kind of assessment can be used for almost any set of material, in some cases a certain kind of test is especially useful. Some subjects seem to fit a certain kind of test more than others.
In math classes, for instance, quantitative assessments often come in handy to measure whether or not a student knows how to solve an equation. There is one correct answer to the problem, and each student’s answer either matches or doesn’t. Some teachers give points for each step completed correctly, while others simply mark the answer right or wrong, but each approach produces a quantitative, objective point amount that the student is awarded for that problem. An 80 on a math test shows that the student knew some of the material, or partially understood it, but didn’t know or understand all of it.
When testing students on English literature, however, qualitative methods of assessment sometimes work better – to test whether students are able to generate their own ideas about one of the novel’s themes, a teacher might give an essay test that asks students to analyze and discuss some aspect of the work at length. A student may earn an A because the teacher believes he has grasped the work at an appropriate level; or he may receive a lower grade if the teacher feels something important was missing. Even though points may be awarded for certain parts, no absolute standard applies in judging the overall quality of the essay.
Gray Areas
In his book Assessment in Schools, David Satterly discusses several major types of classroom assessment. For example, two major kinds are recall/completion and essay. There are many ways to construct each type of test, and a virtually limitless amount of questions that can be asked.
Recall/Completion
Recall/completion questions (like “In what city was the Declaration of Independence signed?”) and multiple-choice questions (like “Which number is the radius of the circle in the diagram?”) ask a student to remember a simple fact, and they are usually meant to be completely objective. There is only one “right” or “best” answer – for instance, “Philadelphia” or “4 inches.” This allows the teacher to page through a pile of tests, easily mark whether or not a student wrote the correct answer, and add that right or wrong mark to the tally of scores to produce a quantitative grade. However, few test questions can really remove teacher discretion from the grading process. The teacher may think there is a single “best” answer, but a question that asks where something occurred can, arguably, be answered to the specific city, state, country, or hemisphere. The Declaration of Independence was signed in Independence Hall, in Philadelphia, Pennsylvania, and in North America; but specific questions – asking “what city” instead of “where” – can help make the answer more clear-cut (Satterly 1989).
Essay
More so than any other type of test, essay tests contain both qualitative and quantitative aspects in full array. Most essay questions require the student to connect ideas, apply concepts to new situations, and, in general, utilize more of the higher-level thinking skills at the top of the Bloom’s Taxonomy diagram. It is indeed difficult for a student to formulate a viable solution to a current political issue if he does not thoroughly understand the arguments on both sides. Of course, the more a question moves toward the qualitative realm – and away from simple rights and wrongs – the harder it is to grade, simply because there is no absolute standard of correctness for the teacher to measure it against.
Perhaps largely due to this workable balance between the qualitative and the quantitative, a well-constructed essay questions is considered by many an excellent way to assess whether a student has reached a “deep understanding” of the material, and is able to reorganize it and reapply it (Borich and Tombari 2004).
Multiple Choice Questions
Click to reveal the answer.
What kind of test item is the following?
“Students, I’d like you to decide whether this scene from the novel is about the theme of social injustice. Be sure to back up your statement with examples from the text.”
- A. Qualitative, because there is no single right answer.
- B. Quantitative, because there is only one answer the teacher will consider correct.
- C. Quantumative, because it is an essay question with no choices.
- D. All of the above.
A. Qualitative, because there is no single right answer.
If a science teacher wants to see how much a student remembers about cell parts and their specific functions, which test method is he/she likely to choose?
- A. A qualitative method in which the student writes an essay analyzing the cell parts and proposing his own interpretation.
- B. A quantitative method in which the student answers multiple-choice questions matching the parts of a cell with their functions.
- C. A qualitative method in which the student picks one cell part to research and draw a picture of.
- D. A quantitative method in which the student writes a report giving facts about the people who discovered cell parts and the background behind each discovery.
B. A quantitative method in which the student answers multiple-choice questions matching the parts of a cell with their functions.
If an English teacher wants to measure a student’s ability to understand two selections from different periods of literature, which test method is he/she likely to choose?
- A. A qualitative method in which the student writes an essay comparing and contrasting features in the two selections.
- B. A quantitative method in which the student answers opinion questions in the multiple-choice format.
- C. A qualitative method in which the student chooses one of the two books and writes about its relevance to today.
- D. A quantitative method in which the student matches the works’ titles, authors, and historical facts.
A. A qualitative method in which the student writes an essay comparing and contrasting features in the two selections.
Which is the best example of a completion question to which there is one single “right” answer?
- A. Where was George Washington born?
- B. What was the name of George Washington’s wife?
- C. What was George Washington’s most important achievement?
- D. Who painted George Washington’s portrait?
B. What was the name of George Washington’s wife?
Which is the best example of a question to which there are many possible “right” answers?
- A. Who wrote The Adventures of Huckleberry Finn?
- B. Who is Huck’s friend and traveling companion in the novel?
- C. What is the main difference between Huck and Tom?
- D. What major American river does Huck travel down?
C. What is the main difference between Huck and Tom?
Essay Question
Click to reveal a sample response.
My subject, secondary English, deals more with qualitative assessment than many other subjects do. An English teacher probably devotes many of her tests to questions that ask students to take ideas from things they have read and apply creative thought to it. For instance, she probably includes essay questions, literary analyses, and oral/written interpretation. But English teachers also use quantitative assessments like multiple-choice and true-false. In my future classroom, I will probably try to use a mixture of qualitative and quantitative assessment: simple right/wrong questions to measure factual knowledge, whether students remember the parts of speech or all the characters’ names, and writing assignments to get students to interpret, create ideas, and think on a high cognitive level. For instance, to test students on a novel they have just read, I might use a combination of 1) an oral class discussion of the novel’s ideas and themes, 2) simple recall quizzes covering plot, character, setting, etc., 3) a writing assignment asking students to create an interpretation of a passage from the novel, 4) some kind of creative project that takes an idea from the novel and builds on it visually. Any combination of these ideas this would allow students to express their understanding in different ways and on different levels and help them really grasp what I’m trying to teach them.
References
- Borich, Gary D., and Martin L. Tombari. Educational Assessment for the Elementary and Middle School Classroom. 2nd ed. Columbus: Pearson, 2004.
- “Bloom’s Taxonomy.” Counselling Services. 2005. University of Victoria. 3 Feb. 2007 <http://www.coun.uvic.ca/learn/program/hndouts/bloom.html>.
- Phillips, Bob. Phillips’ Book of Great Thoughts and Funny Sayings. Wheaton: Tyndale, 1993.
- “Qualitative Properties.” Wikipedia. 18 Jan. 2007. Wikimedia. 3 Feb. 2007 <http://en.wikipedia.org/wiki/Qualitative_properties>.
- “Quantitative.” Wikipedia. 2 Feb. 2007. Wikimedia. 3 Feb. 2007 <http://en.wikipedia.org/wiki/Quantitative>.
- Satterly, David. Assessment in Schools. 2nd ed. New York: Basil Blackwell, 1989.
- Worthen, Blaine R., Walter R. Borg, and Karl R. White. Measurement and Evaluation in the Schools. New York: Longman, 1993. | 2,649 | common-pile/pressbooks_filtered | https://library.achievingthedream.org/hostoseducation/chapter/social-and-cultural-foundations-of-american-educationfeedbackqualitative-quantitative/ | pressbooks | pressbooks-0000.json.gz:23417 | https://library.achievingthedream.org/hostoseducation/chapter/social-and-cultural-foundations-of-american-educationfeedbackqualitative-quantitative/ |
DeaibxYPe-MwsOE6 | 10: Care of the Home and Personal Belongings | 10: Care of the Home and Personal Belongings
Maintaining a clean and organized home is an important task of the Home Health Aide/Personal Care Aide. It helps to provide a home free of infection and pests and promotes good hygiene and physical and psychological well-being. This module will explore the purpose of housekeeping and discuss how housekeeping in a patient’s home is different than in one’s own home. We will learn the importance of using proper body mechanics and how to prioritize tasks in order to be as efficient as possible. We will explore different types of cleaning products and why each are used. Finally, we will discuss important housekeeping tasks to be completed in each room of the house, as well as how to do laundry. | 165 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Allied_Health/Foundations_for_Assisting_in_Home_Care_(McLain_O'Hara-Leslie_and_Wade)/10%3A_Care_of_the_Home_and_Personal_Belongings | libretexts | libretexts-0000.json.gz:12052 | https://med.libretexts.org/Bookshelves/Allied_Health/Foundations_for_Assisting_in_Home_Care_(McLain_O'Hara-Leslie_and_Wade)/10%3A_Care_of_the_Home_and_Personal_Belongings |
m4DUhWa5x0YzDkRI | Mine timbering, by Wilbur E. Sanders, Bernard MacDonald, Norman W. Parlee and others. | PREFACE
THIS book is a collection of articles that have previously been printed in the Engineering and Mining Journal, The Mineral Industry, and the transactions of various societies, the source being stated in a foot-note to each article. The article by Mr. MacDonald was published originally in the Proceedings of the Canadian Mining Institute, and that by Mr. Parlee in the Proceedings of the Canadian Society of Civil Engineers. Permission to make this republication has been courteously granted by the Secretaries of both those societies, and the respective authors have cooperated with suggestions and in the reading of proof. The last part of the book is made up chiefly of articles that have appeared in the Engineering and Mining Journal during the last two or three years. In the absence of any treatise on this important subject, which in the hand-books and text-books on mining is dealt with only in a superficial way, it has appeared worth while to make the present collection, which is offered not as a complete treatise on the subject, but rather as a series of essays which go fully into many important details. It is hoped that a thorough and systematic treatise on mine timbering will soon be written. EDITOR.
MINE TIMBERING, BY WILBUR E. SANDERS
Timbering of shafts, stations, and levels, 7. Shafts, 7. Inclined shafts, 10. Stations for inclines, 13. Alinement of incline sets, 14. Vertical shafts, 16. Cribbed shaft timbering, 16. Halved framing for shaft sets, 18. Square-set shaft timbers, 20. One-compartment shafts, 20. Locating shaft sets, 22. Alinement of vertical shafts, 24. Repairing shafts 25. Timbering shafts in loose ground, 26. Timbering shafts in running ground, 26. Two-compartment shafts, 28. Threecompartment shafts, 29. Four-compartment shafts, 31. Ladders, 34. Shaft station sets, 35. Stations, 35. Levels, 36. Timbering levels in loose ground, 39. Timbering of the working places in a mine, 41. Posts, 41. Cribs, 41. Stulls, 42. Penning, 45. Square sets in stoping, 46. Reinforcing sets, 49. Ore chutes, 49. Waste filling, 50. Methods of framing, 50.
BY BERNARD MACDONALD
Historical, 55. Vein characteristics at Rossland, 56. Preliminary work, 56. Sill-floor construction, 57. Timbers and methods used after sill floor is laid, 60. Per tonnage cost of square-set timbering, 64. Cost data per square set, hand framed, 64. Incidental costs, 67. Limitations of the square set, 67. Reinforcement methods, 68. Angle bracing, 68. Cribbing, 68. Bulkheading, 70. Filling, 70. General remarks, 70.
mine, Atlantic, Mich., 92. Barnum mine, Ishpeming, Mich., 93. Section 16 mine, Ishpeming, Mich., 94. Soft Ore Hematite mine, Ishpeming, Mich., 96. Queen mine, Negaunee, Mich., 99.
Shaft timbering, 108. Drift sets, 110. Square sets, 112. Stulls, 112. Timber pillars, or cribs, 114. Docks, 115. Chutes, 117. Staging, 118. Ladders and sollars, 119. Miscellaneous, 119.
IN this necessarily brief article the systems of timbering dealt with are those in use among the mines of the mountainous regions of western United States. This qualification, of itself, requires no apology; for the cosmopolitan character of our miners — managers and engineers, superintendents and foremen — and their shrewd keenness in devising ways to meet the problems presented in underground workings, in selecting means peculiarly adapted to the end in view, and in improving upon well-known methods already in vogue, have placed the science of supporting mine excavations by timbers, as developed by them, far in advance of that in use among the older and less progressive mining communities. This monograph does not include the methods used in coal mining in the East, or that in use in the copper and soft iron ore deposits of Michigan and Minnesota ; nor does it treat of wood and iron cribbing for round shafts, or of iron supports now used in many European mines, nor of timbering and metal supports used in large tunnels.
The mines operated under these methods present every known characteristic of lode formation. The veins and ore deposits lie at all angles of inclination or dip; they are of all shapes and sizes, from the small seam to immense masses hundreds of feet in width, and of all lengths; while the materials comprising them and their country formations vary in texture from rock of strength sufficient to overlie considerable excavations without extraneous support, to the soft ground which requires not only immense quantities of timber and waste filling to carry the workings safely, but an eternal vigilance upon the part of those conducting the operations.
4 MINE TIMBERLVG
except in the case of prospecting hidden or blind deposits, by means of bore-holes from ;he surface downward, metal mines are tested and all are exploited during their earlier stages by shafts sunk or adit-levels driven in and with the ores. This latter is an axiom in mining during this period of development, and should be invariably followed where possible. When once the ores have been opened up so that an estimate may be made as to their extent and general characteristics, more expensive works necessary to prepare the mine for the larger operations of economic ore extraction may be safely entered upon. It sometimes happens that the required information as to orebodies beneath the surface of a mining claim is sufficiently answered in and by the workings of adjoining properties to make preliminary prospecting of the deposits unnecessary; then systematic plans for operating on a large scale may be properly inaugurated.
It is not the province of this article to touch upon methods of mining in use above ground, whether by openwork, hydraulic mining, or by other processes, but rather to deal with the support of underground excavations by the use of timbers, and the details of mining therewith connected. Nor is it intended to explain methods technically foreign to the subject, although such will be touched upon when used as adjuncts to systems of timbering, as waste filling, etc. In the figures drawn to illustrate the article, sizes of timber most frequently used have been arbitrarily taken for convenience. The figures giving dimensions are working drawings showing the methods of framing, as explained, and can easily be applied to frames and timbers of any desired dimensions.
In developing and exploiting mines the miner should remember that unnecessarily large openings for levels, shafts, and other similar workings, mean not alone the breaking down and transporting of needless quantities of material, but also the added expense of keeping in repair larger passageways than are necessary, an item of considerable importance in heavy or creeping ground. On the other hand, the larger excavations are relatively the easier and cheaper to drive. The rule should be that the size of workings must be ample to carry out their purposes properly, but not larger than is necessary for economy in operation.
It often happens that conditions, local or otherwise, are such that the strongest timbering fails to withstand the pressure to which it is subjected, and other means of support must be em-
ployed. In exceptional cases large excavations may be supported with little or no timbering, but usually waste filling must be extensively used as an adjunct to timbering if the mine is to be kept open. Swelling or "creeping" ground, resulting from the exposure of certain rocks and clays to the air, whereby they expand with a force no timbering can resist, demands prompt attention that the timbers may be relieved from abnormal strain. This is done by making use of an open lining of lagging, through the interstices of which sufficient material may be removed to relieve the unusual pressure upon the frames; a process that is continued as long as the conditions demand. The above scheme is employed at the Ontario mine, Park City, Utah, and in the Never Sweat mine, Butte, Mont., where a system of narrow "square sets/' with open lagging, placed outside of the timbers of the large three-compartment working shafts, has been successfully employed to meet just such conditions in swelling ground.
There are certain established principles connected with the use and framing of mine timbers that should be borne in mind. Pressure is best resisted in line with the grain of the wood rather than across the grain, which maybe made clear by the folio wing explanation:
Let Fig. 2 be a section of timber supporting upon end and side the weight pressures represented by the arrows a and b; a acting in line with the grain of the piece, b at right angles to the grain. As shown in Fig. 1 each individual grain or fiber of which the block is composed resists the pressure a by the strength of the combined fibers of the timber, or in other words by the full strength of the timber itself. On the other hand, Fig. 3, the pressure b acting across the grain is resisted by the power which binds
together the .bundle of fibers that make up the piece, the weight tending to crush them down one against the other until the shape and strength of the timber are destroyed. The writer has himself seen in Cralk's Colusa mine, Meaderville, Mont., 24 in. of squaresawed yellow pine crushed down to a thickness of 8 in. by the weight pressing upon its side, at right angles to the grain of the wood, while the supporting post still retained its integrity.
that the full cross-section of the timber A is supported at either end by the pieces B and D. This joint is without doubt an excellent one when, and only when, the entire pressure upon the frame comes from the direction a or c. The frame, however, is likely to be subjected also to pressures from the directions b and d, to resist which the timbers B and D offer only a portion of their cross-sections while the remaining parts x y of the pieces tend to split off from the larger portions, thereby weakening the timbers by an amount equal to the sections x' y' so removed. A similar result from the pressure c might now cause the portion x z to split off from C, in which event, there remaining, as against the pressure 6, no shoulder upon C to support B in place, the timber B would be forced from its position, causing the frame to collapse.
framing shown in Fig. 4 is not applicable.
The only satisfactory remedy for this inherent weakness of square-shoulder framing is to make use of the mitered joint or beveled hitch, as shown in Fig. 5. In this method, because of the support afforded a timber by the miter of this joint, the pressure from any of the directions a, 6, c, and d is resisted by the strength of the full cross-section of the piece against which the force acts. However, as shown in the piece C, the simple miter is not in itself sufficient to sustain any considerable thrust without a tendency to wedge apart the timbers B and D, and thus destroy the set. Without doubt the simplest and strongest joint obtainable is some combination of the square-shouldered tenon with the miter or beveled hitch. This combination is shown in the joints supporting the piece A. Here the full strength of the timber is obtained, with no tendency to split or slip, and weight up to near the point of crushing only serves to bind the set more firmly together.
sets of timbers.
Round timbers are stronger than square-sawed pieces, in which the grain of the wood has been cut and weakened by the saw. Used in the mine, round timbers are less easy to handle than are the squared; they are less easy to aline properly, and it is impossible to reinforce satisfactorily sets framed from such timbers by the usual false sets or pieces. The bark should invariably be removed from round timbers, as it collects moisture and fungus, and thus hastens the decay of the wood. It also prevents the pieces from becoming properly seasoned before they enter the mine.
TIMBERING OF SHAFTS, STATIONS, AND LEVELS
SHAFTS. — Shafts are of two kinds, vertical and inclined. The former is more frequently used in large operations, where speed and convenience in hoisting are the prime necessity — particularly in connection with the more steeply inclined deposits, and with flat ones and pockets lying entirely beneath the surface.
The usual size for single-compartment shafts, and for the hoisting compartments of the larger shafts in metal mining, is from 4 to 6 ft. in the clear of the timbers; the compartment used to carry water-columns, air- and steam-pipes, and ladders, is frequently made larger in cross-section than the working compartments. The expense of sinking shafts and of keeping them in repair in average ground increases rapidly beyond a certain size; it is therefore considered good practice to make the shafts as small as possible, keeping in view the work to be carried on through them.
Inclined Shafts. — Inclined shafts are used largely during the preliminary stages of development in veins, and other outr cropping deposits that dip below the horizontal at angles too small to allow of the economical use of vertical shafts. Similar methods of timbering both classes of shafts are in use, although at times the timbering of inclined shafts approaches more nearly to that employed in supporting the level workings; as when application is made of the threepiece and four-piece level sets to inclines (Figs. 6 and 7). The single stull piece, with head board, is often used in the mountains when the hanging wall or top rock is of such strength as to require little support.
When the three-piece level set is employed the cap is usually lengthened, and the top of each post fits into gains cut near the ends of the cap. Where a sill piece is desirable the sill is framed in the same manner as the cap, and the posts act as dividers.
A two-compartment shaft is constructed by placing a third post or girt in position at or near the center of the set in much the same manner as are located the end posts or plates.
The three-compartment shaft is similarly constructed by locating two such girts at their proper position, the tenons of the girts being V-shaped. (See Figs. 8, 9, and 10.) Behind or back of the side plates, and in line with the end plates and girts, the
set is tightly blocked and wedged in place. Pole or plank lagging is used where it is necessary to prevent falls of loose rock from the walls and sides of the shaft. Skip-ways are carried by the sill piece or bottom side plate. Guides also are attached to the end plates and center girts when safety devices are used upon the ore-skips.
Other methods of framing the four-piece set, as applied to the inclined shaft, differ from the above framing in minor details, and at the same time allow of the use of the full width of the
shaft. (See Fig. 11.) The halved system of framing, as explained under vertical shafts, is rarely used for the inclines, and then only when posts are employed to form the complete square shaft set.
Stations for Inclines. — The stations constructed for inclined shafts are of two kinds, one being so arranged that the ore cars dump directly into the hoisting skip, held in position just beneath (Fig. 12), while in the other a 25- to 75-ton ore bin is placed
beneath the station and above the shaft, from which bin the ore is drawn into the skip for hoisting to the surface at intervals. This station, while requiring more excavating to construct, is by far the most economical in the end, as the skip can be run entirely independently of the trammers or carmen. (See Fig. 13.)
Alinement of Incline Sets. — Probably the simplest method of alining the side plates of inclined-shaft sets, in order to get them in line one with another, is by the use of the combined straightedge and plumb-bob.
A straight-edge is made of a length greater by a foot or so than the distance between two sets. From the side opposite the true edge is built up a frame, one piece of which is so set that a plumb-line attached at its upper end will hang vertically along a fixed line, marked upon it, when the straight-edge coincides with the true inclination of the shaft, and at the same time simultaneously rests upon three bottom plates. To prevent the plumbline from swinging too freely it is confined at its lower end within comparatively small limits by a cleat attached to the upright piece. (See Fig. 14.) The straight-edge alone is used to locate
the end plates evenly in line with each other. (Fig. 15.) When the sets are placed they are bound in position by hanging hooks or bolts (Fig. 20), as explained under vertical shafts, and when so held are blocked and wedged firmly in place; the straight-edge,
true position during this operation.
Vertical Shafts. — The timbering of shafts varies according to the nature of the ground and the size of the shaft. Shafts sunk in some localities require little if any timbering, while in other places they are supported only by huge timbers that have been framed with the utmost precision.
PLANKS.
Cribbed Shaft Timbering. — In small shafts usually some form of cribbing is used. This system of shaft timbering is the simplest and often the cheapest in use, but it becomes cumbersome and expensive in large shafts. As usually employed it requires little framing, is easy to place, to repair or renew, and to keep properly alined, and its use enables the timbering to be kept even with the bottom of the shaft in sinking, if that be necessary.
The simplest form of cribbing is that of poles, cut to required lengths and placed in pairs across each other, either from above or below. Located in this manner it forms an openwork lining to the shaft. Strips aa nailed to the poles upon the inside corners keep the cribbing in position. (See Figs. 21 and 21A.)
Cribbing is also formed from sawed timbers of various dimensions, the most simple method being that in which planks of the required lengths are placed around the shaft, upon edge, and resting upon similar sets below or supporting similar
sets above. These sets are made to resist the outside pressure, usually, by so placing the two shorter or end pieces that they will hold apart the two longer side pieces, the former in their turn being held in their position by corner strips b within, and nailed up and down the shaft to the side pieces. (See Figs. 22 and 22 A.)
While the method of timbering is extremely simple it is unsatisfactory, and good mining practice makes use of the framed set as being stronger and in every way better. The basis of this system is some form of the tenon and mortise, whereby the ends of the two timbers forming a joint are framed with both a tenon and what might be called an open mortise, the mortise of one piece engaging the tenon of the other and vice versa, to the end that each piece supports or keys its mate in place. See Fig. 23, a, b, and c, which show the more simple forms of this method of cribbing, the latter c being excellent for the reason that it causes the edges of the planks on the sides to break joint with the edges of the end planks in a way to stiffen the shaft and prevent the sets from moving horizontally one upon another. The methods of framing planks for these styles of cribbing are shown in Fig. 23, d and e.
Halved Framing for Shaft Sets. — A development of the tenon and mortise framing of joints is of almost universal application in advanced methods of supporting vertical shafts. This method is 'applied to the cribbed system as shown in Fig. 24, a, A, b, and B. The method of framing the pieces for openwork cribbing is shown in Fig. 24, a, and for tight cribbing, Fig. 24, b.
Fig. 24 B also shows the framing of the opening from the shaft to the levels. False timbers or struts are used temporarily to hold the sides of the shaft intact while this opening is being framed into the level, or the framing can be placed before the planks are removed from the cribbing. A stronger and more satisfactory frame, however, is obtained by the combined beveled hitch and halved joint. The most satisfactory use of this combination is that in which the top and bottom of the side plates are made to break joint with top and bottom of the end plates. (See Fig. 25.) Details of this framing are given in Fig. 25, a and 6, while the method of placing the timbers is shown in the isometric perspectives A and B.
The tight cribbing has been used for large shafts in heavy ground. On the Comstock lode, Virginia City, Nev., several of the important shafts were timbered with a solid cribbing of 14-in. pieces.
Square-Set Shaft Timbers. — In the square-set system, as applied to the timbering of vertical shafts, the heavier timbers of a cross-section of 6 in. and upward are employed. A set consists of the side and end pieces, with posts used to separate the horizontal frames. In the larger shafts divisional timbers, called girts, are used to separate the compartments. The side and end pieces are called wall plates, for the reason that they frame the sides or walls of the shaft. The longer pair of plates are designated as side wall plates — usually called side plates — and the shorter pair as end wall plates, or end plates. Shafts of a single compartment are characterized as one-compartment shafts ; and those which are divided by inner struts or girts into two, three, and four divisions, as two-, three-, and four-compartment shafts. It is doubtful if shafts larger than with four compartments can be successfully operated in deep mining, unless in exceptional cases. The framing of the various sized shafts is very similar, differing only in details that will be explained later.
One-Compartment Shafts. — The timbering of a one-compartment shaft consists of two side plates, a, two end plates, b, and four posts, c, which technically make a single set, successive sets being used to the bottom of the shaft to support the sides, and a lining of plank or lagging, d, is employed to prevent falls of loose material into the opening. (See Fig. 26.) For the wall plates the halved method of joint framing is employed, and at the same time a hitch or square shoulder one inch deep is cut in the tenon as a support for the post. This halving of the timbers, if used alone, greatly weakens them, and the beveled hitch is framed from their inner faces so that their full strength may be brought to the support of the shafts. (Fig. 26, z.) The dimensions of the set are such that the plates when fixed in position are separated 5 ft. from center to center, the practice being to increase the size of the timbers in heavy ground rather than to place the frames nearer together.
In framing the sets the utmost care is taken that the measurements shall be exact, and that the timbers shall be cut true to the line, especially for all important working shafts, large and
from this line. The faces of the tenons and shoulders are made at right angles to, or parallel with, and measured from the face of the plate. These precautions are necessary because of variations in the dimensions of timbers. The halved tenons of each side plate occupy the lower portion of that timber, those of the end plates the upper part, so that when in place the side plates support the end plates by their tenons. See Fig. 27, a, showing the isometric perspective of this shaft.
Locating Shaft Sets. - - When a shaft is to be sunk from a surface too level to furnish possibilities for the disposal of the waste material coming up from below, it is necessary to elevate the top or collar of the shaft above the
accomplished by building up a
cribwork of rough timbers to the desired hight by placing logs of sufficient length in layers by fours or more across each other, with the shaft opening in the center. This cribbing is reinforced by waste filled in against it, and with this as a backing the shaft sets are located in position and blocked securely against the cribbing.
It also happens at times that the top material in which a shaft is to be sunk is too loose to support the sets by simple blocking. In this case
the limits of the shaft, and these extensions are bolted to cross timbers above or rest upon such timbers as a support, the latter being of a length sufficient to bear upon the ground to either side of the shaft, and thus support its weight until it shall have entered rock firm enough to afford secure support to the sets by blocking and wedging in the usual manner. (See Fig. 28, a and &.)
The process by which shaft sets are located and fixed in position as integral parts of the shaft is as follows : The side plates of the set to be put in place are swung to the set above by hanging hooks or bolts, which are made usually of 0.875-in. round iron, hooked at one end and threaded at the other as far as may be necessary. (See Fig. 20.) These hooks are used in pairs, the length of each being about 4 in. greater than one-half the hight
of each set from outside to outside of the wall plates, measured vertically. Thus, with plates of 12-in. cross-section in a 5-ft. set, the length of each hook would be about 3 ft. 4 in., with the bolt end threaded for 6 to 8 in. These bolts are the simplest and most easily manipulated device yet constructed for hanging a set in place. Holes are bored through each side plate, two at fixed points near either end, to receive the bolts, one hole at each end being used to hang the plates to the set above while the other holes are intended for the next succeeding set. Cast-iron washers are used between the plate and nut to give bearing to the latter when binding the sets together. The bolts having been located in the plates, the hooks attached to the loose timbers are caught upon the hooks of the set above, the end plates are put into place, their tenons resting upon the tenons of the side plates, the posts are set in the hitches cut to receive them, and the nuts are screwed down until the frame is tightly bound to the set above. If this upper set is properly level, and the framing of all the parts correctly done, the center line marked upon the new set must be level. Blocks x are placed on the two sides of each corner in line with each plate, between wall-rock and frame, and wedges are driven to tighten the set in its proper position. (See Figs. 26 and 27.) The back of each plate carries a strip nailed thereto, and resting upon this as a ledge for support is placed the plank lagging or lining of the set. Filling is stowed behind the lagging, as the planks are put in position, sufficient to prevent movement of the surrounding ground that would be likely to throw the shaft out of plumb. The same process is repeated as the sinking progresses to the bottom or sump of the shaft. In dangerous ground the practice is not to remove the bolts after the sets have been located, and it is well in any case to leave them in place for several sets from the bottom of the shaft, in order to bind the frames firmly together at this point.
Alinement of Vertical Shafts. — Various methods of alining the timbers of vertical shafts are in use, the most satisfactory probably being the combination straight-edge and plumb-bob. A double straight-edge of a length sufficient to extend over three wall plates in position — about 11 ft. for 5-ft. sets — is made, near the center of which is attached a plumb-line of a length of about 4 ft. A hole is cut in the straight-edge near its bottom end, in which the bob may swing freely, while a cleat attached
just above this point serves to confine the line so that it is quickly located at the center mark, and a line is drawn upon the flat side of the piece parallel to the true edge, with which mark the plumb-line must coincide when the true edge is exactly vertical. (See Fig. 16.)
The set, having been bound to the one above, and blocked to its approximate position, is then alined truly with the two sets above by means of the straight-edge (Fig. 15) and by the combined straight-edge and plumb-line (Fig. 16), and is brought to its exact position vertically, the wedges being driven first at one side and then the other until the set is in place. Usually the sets are alined first at the side, the side plates first at one end and then at the other being brought into position by the wedges, when the process is repeated with the end plates in order to aline the ends of the shaft. Should it be a shaft of two or more compartments the side plates are alined by blocks and wedges in line with the divisional girts separating the compartments after the corners of the shaft have been brought to their places in the same manner as has been described. If the timbers are rightly framed the inner faces of the wall plates should exactly coincide vertically with the inner faces of the sets above. The frame having thus been brought into and fixed in its true position, the lining is placed and the set is complete. (See Fig. 27.)
Repairing Shafts. — When, by reason of undue strain, weakness develops in one or more of the timbers of a shaft, the faulty pieces must be removed and replaced by new ones. Preliminary to this work several sets, particularly those next above the point at fault, are tightly bound together by the hanging bolts. If posts only are to be replaced it may be accomplished by removing the lagging adjacent, excavating enough ground from behind each post to allow of its being driven back from the shaft until it is clear of the timbers, or it may be chopped out with little trouble. The new post is then placed in position from behind, being driven or wedged into place and fitting into the hitch framed to receive each post in the plates. When necessary to replace the wall plates the lagging of the adjoining sets above and below is removed, the blocks are knocked away and the posts taken out, when the plates may be released and new ones put in place. The posts are then returned to their position, the set is bound to the plates above and below by bolts, blocked, wedged, and
alined, lining is put in, and the repairs are complete. It may happen that the ground will not stand during this process, in which case false timbers and lining must be used to hold the walls of the shaft in place.
Timbering Shafts in Loose Ground. — Shafts are frequently sunk in ground that breaks away from the walls before a set can be placed in position, and a quick process of lining the sides of the excavation is necessary. A method of false lining, largely in use throughout the West, keeps the loose earth from falling. It consists of planks of desired lengths placed vertically, and so blocked and wedged into position as to press each piece outwardly against the walls. The top end of the plank is blocked from the wall against the lagging of the last set placed in position, reaching a foot or so above the wall plates of that set. The plank is further blocked and wedged away from the wall-plates themselves, the effect of this being to throw the foot of the piece backward from the shaft against the side of the excavation, and thus prevent the material from coming in. This lining is often carried completely around the shaft. (See Fig. 29.)
FIG. 29. — LINING FOR SHAFTS IN LOOSE GROUND. Timbering Shafts in Running Ground. — In soft running ground, or loose ground too heavy to allow of placing the false
lining above described, a method of spiling is employed that is practically identical with that used for driving levels through similar material. The process consists of supporting the dangerous ground beneath the last set placed in position, by what might be termed an enclosing and protecting shield of plank spiling or forepoling, that is, advanced downward from that set piece by piece as the material is excavated from within. The spiling, a, sharpened at the foot, and often shod with iron at the head, is driven with a sledge, one plank at a time being advanced for a short distance as the material is withdrawn from before it. The spiling is held in position by the set and the material through which it is being forced, only enough of this being removed at a time to allow it to be driven a short distance; otherwise the pressure from without may force the lining into the shaft. Each plank around the shaft is driven successively one by one, until the entire shield has been advanced, when the process is repeated and continued until the shaft has been excavated to a depth sufficient to allow of the placing of another set in position, the idea being to advance the shield by successive small stages during the work.
The spiling is started at a considerable angle, but as it is driven downward it tends to approach nearer and nearer the vertical until, when the new set has been permanently located, tail pieces or bridges b are placed to hold the bottom of the planks in position, and at the same time to furnish ait opening between the plates and the foot of the shield through which to drive the spiling for the next succeeding set. These tail pieces may be permanently left in place, or removed in order to allow the planks to settle against the top of the spiling below, binding the latter in place and making a closer lining. Ledge strips c may be attached to the plates, and the usual close lining placed about the shaft as additional security, and to keep from the shaft material that otherwise might work in at the corners. The posts prevent spiling from being placed vertically so as to form a continuous close lining, which difficulty may in a measure be overcome by diagonal spiling so placed as to cover these openings, whether they occur at the sides or at the corners of the compartment shafts. Where possible the sets should be blocked and wedged to place in order that the shaft may be kept plumb, and the hanging hooks should always be retained in treacherous
ground. The above process is repeated successively until the shaft has entered firm ground, when the usual methods of timbering may be resorted to. (See Fig. 30.)
Two-Compartment Shafts. — In preliminary operations, in a mine where pumping is necessary, two-compartment shafts are employed, one of the divisions being given up to hoisting and the other to pumping and ladders. Both compartments are made of the same size, the usual practice in the West being for each division to be 4 ft. along the length of the shaft by 4 ft. 6 in. across its width, hoisting cages being most frequently constructed for operating in compartments of those dimensions. The timbering of a shaft of this size is framed in a manner almost identical with that of the one-compartment shaft, with the exception that the side plates are made longer, and that a divisional piece, called a center girt, is made to fit by tenon and mortise across the center of the side plates. Center posts are also used to
strengthen and stiffen the frame. The methods of locating and alining the sets are those used for the one-compartment shaft. Three-Compartment Shafts. — Should the mine warrant more
extensive hoisting appliances, a third and larger compartment for pumping is added to the two-compartment shaft, while the smaller compartments are given up to hoisting. Because of the jar and strain upon the timbers from winding, this work should be done in the compartments that are supported by the solid side plate, as they are more rigid and self-sustained.
Although three-compartment shafts are often enlargements from two-compartment shafts, nevertheless most of the large working shafts throughout the West are those of three compartments that have been commenced and carried to the bottom as such. Fig. 31 gives the isometric perspective of a shaft of this type. This framing is such as obtains the greatest possible stiffness and strength for the wall plates, and represents the most advanced timbering in use. The arrangement is excellent. The small cage for the use of the pumpmen, traveling closely against one of the side plates to allow space at the opposite side of the compartment for locating the water-column, air- and steam-pipes, is hoisted by an independent engine, and the safety arrangement for the ladders is carefully designed.
The sets are located in the same manner as are those of the single-compartment shaft. The side plates are hung to the plates above, the end plates are placed in position, the solid center girt is fitted into the mortise cut to receive it in the center of the solid side plate, the divisional girt is located at the joint between the long and short side plates, the eight posts are placed, and the set is tightly bound by the hanging bolts to the set above, blocked, wedged and alined. The side plates are sometimes made of a single piece, framed to receive two solid center girts, which make the shaft more rigid. Long timbers of this kind are difficult to handle in a shaft, and it is not always possible to use them. Where possible they should be placed at the stations, both above and below, in order to make the frame of the station set as strong as possible, as shown in Fig. 31.
The principal reason for the almost invariable adoption of the double-hoisting-compartment shaft in large operations throughout the West is that of balancing the loads in winding. One of the cables winds over, the other under, the same engine-shaft, and when the two drums or reels are both clutched to the shaft the weight of one cage and load acts in a measure to balance the other, thus saving power.
Four-Compartment Shafts. — Four-compartment shafts, with three hoisting divisions, may be divided into three classes, viz.: the single-width shaft, largely used throughout the Witwatersrand goldfields of South Africa; the "L" shaft, now practically abandoned for good reasons; and the double-width shaft, which it would seem is likely to come into general use as being one peculiarly adapted to the vast operations of extensive mining.
In the single-width four-compartment shaft the two end hoisting compartments are employed for raising ore, and, on occasion, for lowering timbers; the third is used in sinking and by the pumpmen, and likewise for lowering timbers into the mine, while the fourth compartment is given up to the pumps, the water-columns, air- and other pipes, and to the ladders. The framing of the timbers for this shaft is almost identical with that for the three-compartment shaft, except that the divisions are such that each section of the side plates supports two compartments. (See Fig. 32.)
The double-width four-compartment shaft practically comprises two two-compartment shafts placed side by side, the end plates being lengthened in order to form a double-width shaft. Two of the end compartments are used for the hoisting of ore and the lowering of men and timbers, one of the two remaining is employed as a cageway for pumpmen and timbermen, with its station cut on the opposite side of the shaft from that for the hoisting divisions, while the other is given up to the uses of the pump and for carrying the water-columns, air- and other pipes, and ladders. See Fig. 33, giving the plan of the shaft, and a, b, c and d the method of framing the timbers, which is similar to that for the three-compartment shaft, and Fig. 34, showing the isometric perspective of the construction.
bers are so long as to render their handling in the shaft difficult, while at the same time the excavation is nearly square in crosssection, and of a size to facilitate the breaking of ground, and the placing of the frames in position. Furthermore, the bracing received by the plates from the interior cross girts, both long and short, greatly solidifies and strengthens the set. The great capacity of this shaft, together with its compactness, strength, and rigidity, and its accessibility for repair, renders it especially adapted to extensive mining operations. As compared with the three-compartment shaft this shaft requires the excavation of but 450 cu. ft. more of material in each 100 ft. of its depth than does the former.
Ladders. — The ladders that are placed in the man-ways of a shaft, and in other inclined and vertical passageways throughout a mine, are usually made in 5-, 10- and 15-ft. lengths or thereabouts. (See Figs. 17, 18 and 19.) They consist of two supporting 2x4-in. scantlings, placed parallel about 14 in. apart, to which are fixed cross pieces or rungs at regular spaces of about 10 in. The rungs may be of wood or iron, preferably the latter, unless the mine waters are sufficiently acid to attack the iron — which is often the case in the deep workings. The wooden rungs are often simply spiked to the scantlings, or they may be set into hitches cut in the edges of the side pieces, and nailed firmly in place. Frequently the scantlings are bored, and turned rungs are fitted into the holes, the ends of the rungs being wedged to hold them in place. While this method makes an excellent ladder, the holes weaken the scantlings materially, and, furthermore, it is almost impossible to replace a rung without destroying the ladder. The most substantial ladder, and one easily repaired, is the following : The inner face of each scantling is bored at the required intervals to a depth of 1 in. in order to receive the ends of 16-in. lengths of 0.75- or 0.875-in. common iron pipe, cut exactly. At every fifth rung smaller holes, concentric with the others, are bored entirely through the scantlings, through which and through the lengths of pipe located at such points are passed 20-in. lengths of 0.75- or 0.875-in. round iron, threaded at the ends to receive nuts. When the different rungs of the ladder have been located in their places these nuts are tightened upon washers fixed between them and the scantlings, binding the ladder frame securely together. These rungs possess great strength,
easily repaired.
Shaft Station Sets. — At various depths, usually at intervals of 100 ft., levels are run from the shaft, to and through the inner workings of the mine, and at such points stations or large rooms are excavated in the walls of the shaft, and timbered to serve as centers for the storage of material of all kinds, whether coming from or to be distributed to the various working places. The construction of these stations necessitates a change from the usual shaft framing at such points, in order to obtain the needed hight for an entrance from the shaft to the station. Should the shaft have been carried below the point for a station, the obstructing wall plates at the entrance must be removed, together with their girts, and the posts both above and below. The longer posts, fitting into the gains framed in the plates, are then located, and distance pieces for the walls and girts for the center of the shaft — the same being tenoned to mortises in the posts — are placed in position, occupying that of the wall plates removed, except that the station entrance is left free of such pieces. The remaining sides of the shaft are then lined with the usual tight lagging. See the isometric perspectives of the three- and fourcompartment shafts. (Figs. 31 and 34.) False pieces or temporary struts holding in place timbers to support the walls of the shaft during this operation are used when necessary.
STATIONS. — The ordinary working station is made of a width, in the clear of its framing, of the two hoisting compartments, or of a width which is enlarged at the pumping stations by an additional chamber usually equal in width to the length of the pump compartment, for the accommodation of the pump; the usual practice being to make the inner faces of the station sets aline with those of the shaft timbers.
In hight the stations are made equal to that of the shaft entrance, less the thickness of the flooring, but the roof is made to slant downward from the second or third station set to the end of the room. The length of the station varies with the conditions, from 20 to 40 ft. being usual.
The timbering of stations consists of the four-piece level sets, enlarged and placed at such distances apart as the nature of the ground requires, usually from 5 to 10 ft. Distance pieces or girts are used to hold the sets in position, this in connection with the
usual blocks and wedging. Ordinary plank lagging prevents the fall of loose rock, and a flooring of 2- or 3-in. planking is laid, to which is screwed a turning sheet of boiler plate, whereon ore cars may be turned or slewed around. A sump tank to hold the mine water that is to be pumped to the surface is framed and placed beneath the pump division of the station.
In loose ground it is necessary to timber the station by a system of loose spiling, analogous to the method explained in driving levels through similar material.
LEVELS. — Levels include all those approximately horizontal workings through which mine transportation to and from the working places is carried on, and include adits, cross-cuts, and
drifts. An adit, usually miscalled tunnel throughout the West, is a horizontal tramway driven either within or from without the ore deposit, and connecting the interior workings of the mine with the surface, while an adit-level in contradistinction includes only those portions which are contiguous to and immediately connected with the adit, and are operated through it. A drift is a horizontal opening driven longitudinally with and in the orebody, its function being to afford a means of communication along the lode. A cross-cut is that part of a level which is driven laterally across the country formation, or across the ore deposit to connect one part of the mine with another. The methods of timbering these various openings are identical, and will be treated under one head.
The timbering of levels is accomplished by what is known as the single-piece, or the two-, three-, or four-piece set, depending upon whether one, two, three, or four timbers are employed. They are also known as the quarter, half, three-quarter and full set. The pieces are known as the post, if approximately vertical, the stull if inclined, the cap or top piece, and the sill or bottom piece. Upon the latter rest the posts of the four-piece set, the sill being used to keep the feet of the posts of a set from being forced inward by exterior pressure, and also where the ground beneath will not support the weight resting upon the set.
Where the sides of a drift are sufficiently strong, when the deposit is of a width of not more than from 15 to 20 ft., a single piece is frequently used. (See Fig. 35.) Should either of the walls prove to be weak, this single piece is supported at either end as shown in Fig. 36, forming what is called the two-piece set. If both walls are too weak to support the single piece, or should the deposit be of considerable width, posts are placed under both ends, somewhat as shown in Fig. 37, forming the three-piece set. This set is, however, usually made from framed timbers, either round or squared; the posts of the set being of equal length, and the sets nearly or quite of equal size. These sets are held in position by distance pieces, either of poles sledged into position between the sets, or of squared timber, in which case the sets are framed with a hitch to receive and support the ends of the piece. Poles
used for this purpose are called "sprags," while the square pieces are known as "girts." The framing of squared or round timbers for this set is practically identical, but round timbers because of
their unevenness usually require that a pattern shall be made as an aid to systematic framing. The three-piece set is usually made of round timbers, with the posts set with a spread or slant outward at the bottom as an aid to resist the outside pressure.
the posts being set upright, making the square set, or with a slant outward as in the three-piece set. The set consists of the cap, sill, and two posts, usually carefully framed. In adits the set is often alined with considerable exactness, and when thus placed the passage presents a pleasing appearance. In adits and crosscuts the posts are usually given a slant. Often, however, this set becomes an integral part of the regular square-set system as applied to the extraction of masses on the levels and in the stopes of the large metal mines. (See Fig. 38, a, 6 and c.) The framing of this set often becomes massive, especially in the heavier ground of adits. A center post is often placed in position for forming the double tramways. (Fig. 39.)
The ground between the sets is held in place by lagging of poles or sawed plank, which rests at either end upon the timbers. Being of comparatively small strength a lining of this character will yield to unusual pressure, and thus give evidence of incipient crushing that would soon destroy the timbers if not attended to.
Timbering Levels in Loose Ground. — For this purpose the process known as spiling or forepoling is employed, its use being somewhat similar to that described under one-compartment shafts. The spiling may be of sawed plank or of poles of the required length, sharpened at the forward ends, and with their heads protected by an iron shoe when necessary. A set having been fixed in position (see Fig. 40) a bridge y is placed upon the cap supported by the blocks x at either end. Between this bridge and the cap the spiling z is started, sloping upward at an angle.
As it is driven forward, piece by piece, the material is picked away from the point of each plank as it is forced ahead a short distance at a time. In this manner the entire shield is advanced through successive small stages until it has been driven forward through about half the distance to its final position, when a temporary false set, a, is located to support the spiling. The driving is then continued until the shield has been advanced to its place. The regular set is then fixed in position, a bridge is placed upon its cap, and the false set removed, which allows the spiling to settle upon the bridge. The same process is continued in excavating for the succeeding sets while passing through similar material until more solid ground is reached. When necessary the same
process is also applied to the sides of the opening, bridging the posts in the same manner as the cap is bridged and similarly advancing the shield. In very soft ground it is sometimes necessary to employ the same method in carrying the bottom of the level forward. In very soft or running ground the edges of the plank spiling must fit closely against each other, and at the same time the face of the working is retained by breast boards held in position by struts footing against the forward set. These boards are advanced behind the forward edge of the shield, being removed one at a time, and placed farther ahead as the material is removed from in front of it, a longer strut being used to support it in its new position.
TIMBERING OF THE WORKING PLACES IN A MINE.
As regards the process of extracting the valuable materials from their places of deposit there are in use many methods well adapted to keeping the workings open under the varying conditions. Of these the most simple are those employed in the horizontal or bedded deposits, where often the overlying rocks are of such strength as to require little support other than that furnished by the occasional pillar of ground left in place for this purpose. Even the material left in these pillars is sometimes removed, and the roof allowed to fall, when it can be done without injury to future operations.
Posts. — The method of supporting the roof of horizontal deposits by posts or props is almost universally employed, and is the most simple artificial means of keeping open the working places of mines of this character. These posts are formed of sections of trees of various diameters and of lengths up to 20 ft. They are placed in a vertical position, normal to the roof and floor of the deposit, with a flat plank, called a cap piece or head board, placed upon the top of each prop to distribute the pressure evenly upon the timber, and to give greater bearing HEAD BOARD, surface against the rock. (See Fig. 41.)
Cribs. — Another method employed is that of cribbing, or, as it is sometimes called, penning. This consists of building up a crib or pen from floor to roof of logs, laid in pairs or in greater numbers across each other. These cribs may be made solid if desired, but this is not often done, for practice prefers to make a single or double pen and fill its interior with waste material, which is usually at hand in underground workings, and the use of which greatly ^^//////^//////////m strengthens the crib. (See Figs. 42 FIG. 42 — CRIB.
and 43.) The stowing of waste in underground excavations from which the valuable materials have been extracted is often resorted to and forms a solid filling that will, with comparatively
little subsidence, support any pressure. Waste filling is frequently used in connection with and as adjunct to the various systems of timbering employed in supporting the walls of ore and other deposits. It forms the only permanent and certain means of retaining the walls of orebodies in approximately their original position.
The metal mines of the West for the most part consist of deposits that dip below the horizontal at varying degrees up to the vertical, the dip of the blanket veins and other bedded deposits depending upon the uplift of the enclosing formations, while that of the fissure veins follows the course of the fissures cutting through the earth's crust. Contact veins may present the characteristics of either of the above mentioned classes, and the chambers or isolated pockets of valuable materials may follow certain lines of deposit, or be without regularity or regular form.
In size these different deposits vary from the deposits too small to be successfully worked in a commercial way, to immense masses of ore, the extraction of which brings into use all the science of the miner and of mining. Some of the methods in use for timbering these excavations, during and after the extraction of the ores, are but the application of old methods to present use, while other systems are distinctly modern, both in origin and application.
Stulls. — Of the older methods there is principally and primarily the stull system, which is but the application of the post of the flat deposits to the use of the inclined veins. Stulls are almost universally employed in mining the smaller veins, with or without waste filling as an adjunct. They consist of sections of trees, pine, fir, oak, or other substantial woods, round, and peeled
of their bark. These sections are of all lengths up to about 20 ft., as may be required at the points to be timbered, and in diameter up to about 4 ft. The greater the diameter the greater the strength of the timber. Length beyond certain limits decreases the power to resist pressure, as the piece is more liable to bend or buckle under the weight.
Like the post the stull is placed with a head board to distribute the pressure, and to give greater bearing surface to the stull in supporting the hanging wall of the deposit, while the foot of the stull is trimmed and squared to fit more closely into the "hitch" cut into the foot-wall to prevent the timber from slipping from its place. (See Fig. 44.)
Unlike the post the stull is
not located in position in a line normal to the walls of the deposit, but at an inclination thereto approximating at a certain ratio to the dip of the vein, the angle of underlie of the stull (see Figs. 44 and 50) being about one-fourth of the angle of dip of the deposit, thus:
The reason for this underlie of the stull is that if the piece were placed at right angles to the walls of the vein a slight movement of the hanging wall would cause the stull to fall. Also the stull usually carries the weight of waste filling above the levels, and this it would be unable to do if placed perpendicular to the wall, while this weight tends to wedge the piece more tightly into place if placed at an angle above the perpendicular to the walls.
In wide veins stulls are often reinforced, so as to enable them to bear both the vertical weight of the waste filling above and the side pressure of the walls, by what is known as the double-stull method. This consists of false stulls placed beneath the stull proper, the former being placed with a foot-hitch, and the stull, supported in its position by logs resting upon FIG. 45. — STULL AND FALSE two or more of the false stulls beneath STULL. to either side, footing against the foot-
is necessary that will change the vertical weight due to waste above into a diagonal thrust against the walls. This is done as is shown in Fig. 47, a by means of the saddle-back system of bracing,
and b by the arch with key-piece. This saddle back is sometimes used, as in Fig. 48, to carry the weight of waste filling above, but it is without value to resist side pressure.
Penning. — A method of timbering known as penning is sometimes employed in the inclined veins, and is nothing more than the crib of the flat deposits applied to the incline. It consists of cribs of logs built up from the foot-wall of the vein to the hanging wall, which it supports. Occasional longer timbers are
used to tie the cribs together, and for the purpose of forming sills and caps for the passageways of the mine, as shown in Fig. 49. This method of using timbers for keeping open the working places of a mine is expensive, and requires quantities of timbering, but in connection with waste filling it is about as permanent as any method of timbering can be. It also has the advantage of a certain flexibility without weakening during movement.
Square Sets in Sloping. — This system of timbering is peculiarly adapted to the extraction of ores occurring in large masses. In fact, the size of the deposit matters little if waste filling be used in connection with the sets. The method requires vast quantities of timber, and the framing of the pieces is no small item of expense, but the handiness of the system is so great, and its adaptability to all the needs of mining operations in extracting the valuable materials from their places of deposit is such that it has replaced many of the cheaper systems of timbering. Indeed, it is a fact that its use in large operations is often found to be cheaper in the end than are many of the supposedly more eco-
nomical methods, and this in spite of the fact that the framing of the sets involves no small item of outlay. Briefly, the system consists in filling up the excavations resulting from the extraction of ores with what might be termed open blocks or cells of timber that may be added to and extended indefinitely in every direction, lengthwise of the deposit, across it, and between the levels, while the slope of the body matters little for the reason that, in following the ores between their walls, sets may be extended laterally
encroaches upon the timbering.
The set is made up of posts, cap, and girt, the former being as usual placed in an upright position, in line with the posts above and below. The cap rests upon the top of the post, and is invariably placed across the deposit, the cap of one set becoming in effect the sill of the set next above; while the girt, which likewise is set upon the post, is located along or longitudinally with
the run of the orebody. The sets are, in the best practice, framed for a hight of 7 ft. in the clear of the timbers; the reason for this being that this length obtains the full strength of the frame at the same time that it saves timber in the mine, and leaves sufficient hight for passage without inconvenience. This hight also allows of placing the reinforcing sets in position, and still permits passageway if necessary. Across the deposit the caps are made
of a length such as will set the posts 5 ft. apart in the clear of timbers, which gives room for working the air drills in the breasts of ore, and for other work at end points. Along the length of the orebody the girts are made to separate the cross frames by a distance of 4 ft. 6 in., adding somewhat to the number of such frames and thus giving greater resisting power to the sets against thrust from the side, from which direction the maximum pres-
sure usually acts against the timbers. (See Fig. 51.) In this figure the method of locating the sets is shown in isometric projection, and also that of placing the different timbers of the system.
Usually a heading or drift is first run along the level, as near to the center of the deposit as may be, although this is not essential, and along this excavation the sets are placed from which to build up the more extended timbering. On the floor of this drift are laid the two-post sill pieces, the sill girts are placed in position as is shown in the figure, then the posts are located, and upon them is placed a cap piece across the drift, while a girt connects this cross frame with the last one placed in position. The frame is now blocked and wedged against the top or back of the drift, and the set is completed. As material is removed from either side of this drift, one-post sills are laid upon the floor of the excavation and penned to the two-post sills already located,' a sill girt is placed, the post set upon the framing fitted to receive it, and cap and girt hold its top in position. It is then blocked and wedged firmly against the ground above, and also from the side. A 2-in. plank roofing is laid from cap to cap above the set, which performs the functions of a floor for the set next above as the timbering is carried up. When the footwall of the deposit is reached, the sets are carried up along its slope by means of the cap-sill, a timber which combines the functions of the cap and the sill, also shown in position in the figure. Upon these cap-sills as a foundation are built up a new line of sets, and the process is carried on to any extent by repetition. Above the sill floor, as the ground is excavated, posts are set into the gains formed by the framing of post, cap, and girt beneath, and the timbers are continued upward, outward, and lengthwise as far as may be necessary. The sets from one level are carried up to those of the level above, when short sets are placed in position to carry the weight of the upper framing.
Reinforcing Sets. — When the timbering is carried into unusually heavy ground, or where it is forced to carry a great weight, it is frequently necessary to reinforce the sets across the deposits in line with the greatest pressure, and this is done by what is known as the diagonal brace, the three-piece set, the full or four-piece set, the "N" frame brace, the "N" frame set, and the "X" frame brace. These are all shown in Fig. 51.
level to that level so that it may be loaded into cars and carried to the shaft for conveyance to the surface, a storage bin and passageway combined is necessary, and this is obtained by lining one of the sets as it is carried up from the level by a close lining of 2- or 3-in. planking, preferably the latter. These bins are designated as chutes, and the framing at the bottom of them whereby the ore is delivered into the cars is called the gate of the chute. This is made by constructing an inclined flooring, with sides, that shall project beyond the side of the chute into the tramway sufficiently far to allow the rock to fall from it into the car. Cross timbers are placed across the chutes at varying hights of about 30 ft. in order to break the fall of the rock so that it shall not destroy the gate frame. In keeping the chutes near the center of the deposit they are as often as is necessary offset toward the floor wall on an incline from one line of sets to the next lateral set on the floor above.
Waste Filling. — In average ground no system of timbering will long sustain the walls of large excavations, and waste rock from the vein and walls, especially the hanging wall, is employed for filling up the spaces between the timbers in order to make a solid filling that shall hold the ground in place. Passageways are strongly reinforced, and the flooring is removed from the different floors when waste is thrown into the excavation from above.
Methods of Framing. — There are several methods of framing the timbers of square sets in order that they shall come together from the six directions in a manner best suited to the needs of the occasion. Fig. 52 shows the method of cutting the timbers in use in the Anaconda mine, Butte, Mont., a giving the isometric perspective of the post, cap, and girt as shown separately, b showing their appearance when joined. The Eureka method of framing is shown in Fig. 53, and is very similar to the Anaconda frame, the latter having one more section cut from each side at each end of the girt. Both of these methods are used for opposing
Eureka Fra
pressure from the sides of the veins, the caps abutting against one another to secure the greatest strength from the timbers; but by transposing the timbers of this set, so that the posts shall rest end on end upon one another, vertical pressure may be best resisted. This is shown in the Burlingame frame (Fig. 54), a separated and b joined, which is the Eureka framing with the post of the latter forming the girt of the former, the cap of FIG. 53. — * EUREKA the Eureka the post of the former, and the girt METHOD. of the Eureka the cap of the former. Fig. 55
levels. The Eureka framing is now used in
some of the Anaconda mines as being the simplest and cheapest method of framing. Fig. 56 furnishes the details of framing timbers for the Anaconda set. The square-set system of timbering was originated to meet the needs of the situation as developed in the workings of the Ophir mine, on the Comstock lode, Nevada, by Philip Deidesheimer.
Important details connected with the methods of timbering herein described, and other systems now in successful operation among the metal mines of this country, are excluded from this
IN mining operations, when the ore extracted exceeds a width, of 12 or 15 ft., it has been found that the cheapest and only effective method of timbering is by the square-set system.
The system may be generally described as a rectangular skeleton framework of timbers, extending from wall to wall of the vein as exhausted, the different members of which are so framed as to stiffen and support each other, and equalize and distribute local strains after the manner of a truss.
Comstock lode, in 1860.
In Monograph IV of the United States Geological Survey, " Comstock Mining and Miners," the following reference is made, which will be found interesting under this heading:
"At the 50-ft. level (of the Ophir mine) the vein of black sulphurets was only 3 or 4 ft. thick, and could readily be extracted through a drift along its line, propping up the walls and roof, when necessary, by simple uprights and caps. As the ledge descended, the sulphuret vein grew broader, until at a depth of 175 ft. it was 65 ft. in width, and the miners were at a loss how to proceed, for the ore was so soft and crumbling that pillars could not be left to support the roof. They spliced timber together to hold up the caving ground, but these jointed props were too weak and illy supported to stand the pressure upon them, and were constantly broken and thrown out of place.
were unable to carry them off.
"The company was at a loss what to do, but finally secured the services of Philip Deidesheimer, of Georgetown, California, who visited and inspected the treasure-lined stopes of the Ophir."
During Mr. Deidesheimer's engagement at the Ophir, all the principles of square-set timbering were evolved under his immediate supervision, and the wide and rich orebodies occurring in that mine were successfully extracted without the loss of ore or injury from caving by the use of this system. The system was then used in all the mines on the Comstock lode, and subsequently in all metalliferous mines elsewhere where the orebodies exceed a width of 15 ft., the extreme width that it is practical to timber by stulling.
The "square set" has undergone numerous modifications of detail in dimensions and the framing of its members in the various camps where it has since been used, owing mainly to local conditions, the dip of the vein, and the character of the orebodies and the enclosing rock.
VEIN CHARACTERISTICS AT ROSSLAND
In the Rossland mines, the ore deposits have widths ranging up to 100 ft. or more, and lengths of several hundred feet along the veins. The veins are sheer zone fissures, the vein-filling consisting of country rock, which is now found replaced, and cemented to various degrees of completeness by auriferous pyrrhotite and chalcopyrite.
The ore and the enclosing rock may be designated as extremely hard, and the veins dip at angles of about 70 deg. These conditions facilitate and simplify timbering, without, however, doing away with its necessity.
or stopes.
The first work in opening up an ore shoot or deposit preparatory to extraction consists of running drives or drifts through it from the level stations at the shaft, which are generally cut at
distances of from 100 to 200 ft. in depth below each other. Such drives may happen to be run along either wall of the vein, or through the vein at any point or distance (usually varying) from either wall.
These drives are considered as random bores, made longitudinally through the vein to determine, in a general way, its course or strike, and the behavior and characteristics of the ore shoot. They serve, besides, as preliminary thoroughfares for the traffic, drainage and ventilation necessary for the preparatory work of stoping, to be hereafter described.
As generally run in the LeRoi vein, the drives have widths of about 6 ft., and hights of about 8 ft., and require no timbering, owing to their comparatively small size and the hardness of the vein rock.
When it is decided to begin stoping on any new level, the first work done is to excavate the ore along the drives from wall to wall of the vein, making the excavation of sufficient hight to receive the sill floor set of timbers, as the first series of square sets on the level is called, and to leave a space of 2 or 3 ft. over the set. This space serves to provide room for blocking and wedging the timbers to place, and to receive a layer of old timbers, which act as a cushion in preventing the possible breaking of the timbers by the masses of rock that must be blasted down on them, as the work of stoping out the ore above proceeds.
SILL FLOOR CONSTRUCTION
The sill floor is a framework, made of 10x10 = in. sawed timbers, laid down on the working level in the orebody. They serve as the sills or foundation timbers on which the square sets are to be erected. It is, therefore, the first as well as the most important part of the square-set system of timbering.
Figure 57 shows the sill floor as laid down and ready to receive the sill floor set of timbers. The members of the sill floor consist of three pieces: the stringer, or long sill; the spreader, or short sill ; and the butt spreader, or brace. These members, when repeatedly laid in duplicate, will make up a sill floor to any extent required by the size of the deposit.
The long sill measures 15 ft. over all, and is framed from a 16-ft. timber, which allows 6 in. to be cut from either end to square the piece and remove sun cracks.
The short sill, as framed, measures 5 ft. 4 in. in length, over all, three of which may be cut from a 16-ft. timber, if it overmeasures a few inches, as it generally does, and the ends are sound.
The butt sill or brace is framed of varying lengths to suit the existing space, which generally varies owing to local bulgings or contractions of the vein. It is framed on one end exactly like the short sill, while the other is cut square or beveled to fit or butt against the wall-rock, from which it is wedged tightly to place against the long sills.
glance at the figure.
In laying the sill floor, the long sills are set ends abutting flush against each other, and as nearly as possible parallel with the general strike of the vein, ignoring any local bulging of the walls.
The first sill is laid close and approximately parallel to the foot-wall, in which position it is leveled and held by blocking or butt braces; the other long sills are laid paralleling this one at proper distances apart, that is, 5 ft. 4- in. between centers. The cross sills fit on top of these, lying level with them, the ends being halved in framing to rest into similar halvings in the long sills, and to abut flush against each other and extend endwise from wall to wall of the vein.
When the long sills reach as near the hanging wall of the vein as desirable, they are braced from it by the butt spreaders or by blocking, wedged tightly to bring all the members into proper position. The philosophy of this design of the sill floor is as follows :
The long sill is made 15 ft. in length, so as to better sustain the superstructure of square sets erected on it when the ore upon which it rests comes to be stoped away. For instance, when the ore is being blasted from under the sill floor by the work of stoping coming from the level below, and the blasting tears away a portion of the ore upon which the sill floor rests, making an opening, as it generally does, of, say, 8x8 ft., the long sills would over-
reach such opening, and one or both ends would rest on the solid rock beyond. Nor would the short sills drop away through such opening, owing to the fact that they rest on the top of the long sills, as previously described and shown in the figure.
Through the opening thus made in the ore, the portion of the sill floor exposed would be supported by posts set on the timber sets in the stope below. Thus the long sill operates to allow the work of stoping out the ore upon which the sill floor rests to be safely conducted, if such portions of the sill floor as become exposed as the work proceeds are properly supported by posts from the timber work underneath.
TIMBERS AND METHODS USED AFTER SILL FLOOR is LAID
The first tier of square sets erected on the sill floor is known as the "sill floor sets." The assemblage of the framed timbers into square sets then proceeds upward, by floors, set over set, vertically, pari passu as the work of stoping exhausts the vein. The timber structure over any level is referred to in subdivisions as the "sill floor sets," "first floor sets," "second floor sets," and so on until it reaches the level above and catches up and supports the sill floor on that level.
carries with it the data for a general calculation of the portion of the vein exhausted over a level, as each set of timbers in place indicates that 9 ft. vertically and 5£ ft. horizontally of the vein are exhausted, 9 ft. being the bare hight and 5^ ft. the width of space required for a set of timbers. And each square set in place indicates that 24 tons of vein matter have been extracted.
Aside from the sill floor, all the timbers employed in the square-set system, except the planks for floorings and chutes, are framed from round logs. These logs are preferably of red fir, it being the strongest native timber, but pine, spruce and tamarack may be used. When cut in the woods, the logs are peeled and
allowed to season for a period of from six to twelve months, during which time they lose about one-third of their green weight, which is a very important advantage in subsequent handling. In diameter, they range from 12 to 20 in., but generally average about 16 in., and are sawed in lengths of 16 ft. 6 in.
The logs may be framed by hand or with machine saws into the various members of the square set, as follows, viz.: posts, caps, girts or braces, and butt caps. Like the members of the sill floor, these members may be duplicated to any extent required by the size of the excavation to be timbered.
spaces as may exist.
The details of framing the logs into members of the square set are plainly shown in Figs. 57 to 63, and need no further description. The philosophy of this method of framing the timbers is that the cap pieces of the various sets form continuous stringers of timbers running horizontally from wall to wall of the vein, no matter what this distance may be. Such stringers offer the end grain or greatest strength of the timbers to the walls, from which the greatest strains are generated. The posts and girts rigidly support the stringers thus formed of the several cap pieces in true horizontal position, bearing on the joints from right-angled directions, while the cap pieces and the girts support the posts in true vertical position.
The whole framework forms a strong, rigid structure, capable of indefinite extension upward and longitudinally as stoping proceeds, allowing at the same time for any expansion and contraction in width to suit such irregular widths of the vein as may occur.
Besides the functions of the various members of the squareset system to support each other in the manner described, that of the cap pieces is to receive directly and sustain the strains coming from the walls of the exhausted deposit, while that of the posts is to support the vertical weight coming from the undercut ore deposit and the broken ore lying on the floors, but strains coming from any direction are distributed over all the members of the set.
The system possesses, to a considerable degree, the qualities of a truss, and makes it possible to extract all the ore of any deposit and effectually secure the enclosing walls from caving in. When the framework comprising the sets is erected, a floor, consisting of 3-in. plank, is spiked down on the caps of each floor set. These are the working floors on which the miners operate the machine drills, in the method shown in Fig. 58. When the ore is dislodged from the vein by blasting, it falls on these floors, where the waste or second-class ore may be sorted out from the shipping ore. The shipping ore is shoveled into chutes which are built of 4-in. plank spiked to the timber framework and carried upward with the square sets, as shown in the
figures. The second-class ore, or waste sorted out, may be stored temporarily or permanently in the framework of the timbering, from whence it may be drawn off at any time through chutes, should removal elsewhere be desired.
Figures 58 and 59 are ideal longitudinal and cross-sections illustrating the method of timbering and the work of stoping as it is carried on between the levels. The original position of the level drive, as already stated, furnishes the point from which the excavation of the vein matter for the sill floor is commenced.
The step method of excavating the ore is shown in Fig. 58, where stoping is proceeding in double-headed steps, each step excavating the ore from wall to wall and having a vertical hight of 9 ft. in the clear, which allows of the erection of one floor of timber sets, which in turn provides the scaffolding from which the miners may attack the ore above.
In stoping out the ore on any level, the ordinary method is to keep the sill floor at least 30 ft. in advance of the first floor, and it about 30 ft. in advance of the second, and so on, as is shown in Fig. 58. One machine drill, or generally two, in case the vein is wide, are assigned to work the two opposite headings of any floor, going in opposite directions, working on each heading alternately. When one face is drilled and blasted, the machine drills are changed to the opposite face, and the shovelers pass the broken rock into the chutes, or sort it, if sorting is required. When the ore broken is thus removed from the face the timber gang erects another unit of timber there, and the stope is again in readiness for the machine drills, which have by this time finished drilling on the opposite face.
Generally the step method of stoping proceeds in opposite directions from a raise run through the orebody between the levels, as shown in Fig. 59. The framed timbers are delivered in the stope by dropping them down through this raise or hoisting them from the level. Sometimes the framed ends of the timbers are injured by dropping them through the raise, but as a rule no material injury is done to them, while the time gained by this method is a very important factor in cheapening the cost of timbering, compared with hoisting piece by piece from the sill floors underneath.
After the sill floor is laid and the framework started, a square set, which is made up of one post, one cap, and the brace, consumes 18 ft. 6 in. running feet of logs.
The logs peeled and seasoned cut measuring 16 ft. 6 in. cost $1.20 each delivered f.o.b. the cars at the works, or about 8c. per running foot. Therefore, the 18 ft. 6 in. required for the set would cost $1.48, or say $1.50, unloaded in the framing shed, provided the logs are not cut to waste in framing, which may be avoided with a little care and foresight.
These costs last given above may vary greatly, being increased or decreased with the completeness of the facilities for handling the framed timbers; the cost of the several items as stated may vary accordingly from time to time, but the total will be about the average cost, and will closely approximate that of carefully supervised operations. Therefore, from the foregoing it will be seen that the cost of the square set placed in the mine will come down, as follows:
When framed by machine saws, the cost of framing a square set does not exceed 30c., including the cost of power, as against 55c. by hand, a difference of 25c. per set. Therefore, if the framing is done by machinery, the cost of a set in place would be S3. 75 as against $4 as shown above when the framing is done by hand work.
The per tonnage cost for timbering by this method works out as follows : The average space to be excavated for each square set is 5.3 ft. wide by 5 ft. long, by 9 ft. in hight, or 240 cu. ft. The Rossland ores, being heavily impregnated with iron and copper pyrites, yield a ton of 2000 Ib. for each 10 cu. ft. of ore in place; therefore, from the 240 cu. ft. of vein required to be excavated for a set of timbers, the yield will be 24 tons. If the timbers were. framed by hand the cost of timbering, so far as described, would be about $0.17 per ton; if by machinery, $0.15.6, a difference of $0.01.4 per ton in favor of the machine-framed sets.
In addition to the costs above tabulated, there still remain the costs of the chutes, floors, ladders, and railings necessary for the convenience and safety of the miners and the passage of ore and supplies. These require, on an average, about 100 ft. of lumber, board measure, per square set, which, at $11 per 1000 ft., would add for the lumber $1.10, and for placing it, say $0.10, or a total of $1.20 to each square set, which would then cost, in the
case of hand framing, $5.20, or a total cost of $0.21.6 per ton of crude ore; and in the case of machine framing, $4.95, or a total cost of $0.20.6 per ton of crude ore.
INCIDENTAL COSTS
The cost of timbering, per ton of ore shipped, would be greater than the figures given above in proportion to the quantity of waste or second-class ore that would be sorted out from the crude ore extracted.
In the Rossland mines about 20 per cent, of the ore mined is sorted out and goes to the second-class ore dump to await profitable treatment, expected to come in the future. Deducting 20 per cent, of the 24 tons of crude ore in a square set, there would remain 19.20 tons as the shipping ore, against which the total costs of the square set as above, $5.20 or $4.95 as the case might be, would have to be charged. This would raise the per tonnage costs on the ore shipped to about $0.27 and $0.26 respectively.
Where there is a reasonable expectation that the second-class ore will eventually pay a profit after suitable treatment, it would be only fair to charge a pro rated cost of the timbering to it, and the cost would then remain $0.20.6 and $0.21.6 per ton as above.
In cases where, on account of bad ground, angle bracing, bulkheading, or cribbing and filling would be required, the per tonnage cost would be still further increased, but to a comparatively small extent.
LIMITATIONS OF THE SQUARE SET
The limit of the capacity of the square-set system as already described, without any reinforcing devices to withstand the pressure that may be exerted on it by the enclosing walls of an orebody when that orebody is extracted, may be reached.
This limit depends on the nature of the walls enclosing the deposit, and the extent of the excavation. If the wall-rocks are solid and do not swell on exposure to the air and dip at a high angle, the orebody may be extracted between levels, say 100 ft. apart and for a length of 200 or 300 ft. along the vein, and the pressure likely to be exerted by the walls will be sustained by the skeleton square set without reinforcement of any kind.
If, however, the vein dips at a low angle, and the wall-rocks are decomposed, or of a talcose or serpentine character, and disposed to swell, the pressure that might be exerted on the timbers, when even a comparatively small excavation of the
orebody has been made, may cause them to crush, " jack-knife," or collapse, allowing the wall-rocks to cave in and close up the stope. When the members of the square set become squeezed out of the truly right-angled position which they should occupy, their capacity to resist wall pressure or strains from any direction is practically nil.
When, owing to wall pressure or imperfect erection of the sets, " jack-knifing " of the square sets results, the cave-in which sooner or later will follow, with disastrous consequences, may be prevented by either bulk-heading, cribbing, or filling the skeleton framework of the timbers.
The cost of the foregoing methods of reinforcement, which are the only practical ones that can be successfully used in bad ground, cannot be given with any general degree of accuracy, as that is so much affected by the local conditions in each case.
REINFORCEMENT METHODS
Angle bracing. — If, after the square sets are properly erected in place, the members manifest an inclination to swing out of the right-angled positions they originally occupied to each other, this tendency may be arrested and prevented by a system of angle bracing. This consists of placing diagonal braces made of round or square timber on the sill floor and against the foot of the posts, and leaning the heads so they will fit snugly against the top of the posts underneath the caps or girts, as the care may be, of the next adjacent set. The head of this diagonal brace should lean in the direction from which the pressure comes. This method is illustrated in Fig. 62.
Cribbing. — When the square sets manifest a stronger tendency to swing than in the case referred to, the collapse threatened may be prevented by crib work. This consists of crossing alternate layers of round or square timbers of any convenient size between the posts of the sets until the space between the sill and cap is filled, as shown in Fig. 63. This crib work may extend from wall to wall through two or more rows of sets if required, and the spaces between the sets thus cribbed may be filled with waste rock, but this is called "filling," and will be referred to under that heading below.
Bulkheading. — This method of reinforcement consists of placing timbers closely together in much the same way as the crib work above referred to, and wedging them tightly between cap and sill.
Filling. — This method consists of filling the spaces between the members of the square set with any material such as waste rock, earth or sand. When the filling is done it is retained within proper bounds, and the necessary passageways are kept open through the timbers by building crib work around them as described.
Waste rock for filling purposes is generally secured from the development or dead-work that is being prosecuted in other sections of the mine, but where a large quantity is required, it is often found necessary to mine it specially for that purpose, or draw it from the waste dumps on the surface. About 8 cu. yd. of material are required to fill the vacant space of the frame of a square set, and the cost of such filling will be the cost of obtaining and placing such material, together with the crib work required to retain it within proper bounds.
occur.
Where favorable conditions, such as railway transportation and a moderate supply of timber, exist, it is comparatively cheap. If care is taken in the construction of this system in the mine, it ensures that all the ore existing may be extracted without injury to the workman or the mine. Round logs or sawed timbers of any dimension, ranging from 8 in. upwards, may be used, but the sizes are governed by the economic conditions and mining requirements.
In the mines of Rossland, the round logs or timbers used for the square sets cost $1.20 for each log 16.5 ft. in length f.o.b. the framing shed at the mine. These logs are cut in the state of Washington, and delivered over the Spokane Falls and Northern Railway on flat cars, over distances ranging from 45 to 75 miles, each flat car being loaded on an average with 60 logs. The unloading at the framing shed is done in a few minutes by cutting
railway terminus, the expense will be correspondingly increased.
In every mining camp there will be more or less variation in the method of framing, and in the cost of the square sets in place, also in the tonnage of ore to be extracted from the space occupied by each square set.
Where the dip of the vein is at a flat angle or the walls are bad, shorter posts than those described herein will probably be more advantageous; the more vertical the dip of the ore deposit, the longer the posts may be, and vice versa.
Where sawed lumber is comparatively cheap, 3-in. plank is preferable to lagging poles for floors, on account of the better floor it offers for shoveling, and the fact that it may be removed and re-used.
BY NORMAN W. PARLEE
THE method of mining to be adopted in any particular mine depends upon a number of important considerations. Among these may be mentioned the size and attitude of the orebody or deposit, the hardness and rigidity of the ore and adjacent rock, the quantity and quality of timber available and its cost, the price of labor, and the value of the product to be mined. Generally speaking, if a narrow vein is to be worked, stull timbers are used, the limit being a width of about 15 ft. As the vein widens beyond this, stulls are out of the question, and another system must be adopted. The method then employed may be the square-set system, or a filling method, except in case of soft ore, when a caving system may be followed. There are a great many modifications of all these systems to suit circumstances and conditions, and it is the intention in this paper to describe and discuss them as carried out in those mines in which the writer has worked, and in which he has become more or less familiar with the methods in successful operation.
Queen mine Negaunee, Mich.
In nearly all these mines the methods used apply principally to mass mining in large bodies of ore. The one exception is the Atlantic mine, which has a narrow deposit, and is mined entirely by the old-fashioned stull method.
LE Roi MINE, ROSSLAND, B.C.
In this mine there are one or more veins or ore shoots of varying width and carrying the minerals pyrrhotite, chalcopyrite and iron pyrites, and mixed with these more or less disseminated gold. It is the gold, however, that affords the principal value of the ore, and without it there would be no Rossland. The vein is of a pockety nature and some of the pockets are of very large size. The dip is about 70 deg., and an incline shaft was sunk at about this slope. As depth was attained it was found that the vein pitched a little steeper, and the shaft was given a steeper pitch also, thus forming what is called a "knuckle" in the shaft. This knuckle afterwards became a source of considerable trouble, because, at high speeds, the skip was liable to leave the track.
At intervals of 100 ft. drifts were run on the lead, and the deposits thus opened up. The first shaft had three compartments timbered with the ordinary square shaft sets. Sinking was carried on with three shifts of miners working eight hours each, and the rock broken was hoisted to the level above with a bucket and air hoist. As the shaft became deeper the ore and rock were hoisted by skips, run on the balanced principle. A pentice of about 15 ft. of rock was always left in the shaft at each level, and served as a protection to the shaft men working below. It was located under the two hoisting compartments, and connection was made below by a passage at the side. Each drift was usually excavated before being timbered.
At each level, drifts were run on the vein in the ordinary manner, dimensions being 6x9 ft. In the earlier workings the tracks were laid very poorly, and were often the cause of a great deal of trouble and delay, when a large output was desired. But as time passed improvements in this, and many other respects, were inaugurated, and the tracks were laid to a grade of from 7 to 10 in. per 100 ft. Track laying is a very important matter in the economy of a mine, and a good track will always pay for itself 'many times over. The tracks should not only be good, but there should be plenty of them, placed so that they will be close to the rock to be removed. In drifts movable lengths of 8 to 10 ft. should be used. This saves shoveling to a long distance, by placing them in position as soon as there is room,
and enables the mucker to work to advantage, until there is sufficient space for the ordinary 16- to 20-ft. rails. The rails are laid on 4x6-in. ties, 3 ft. in length, and placed about 4 ft. apart, the rails weighing 16 and 20 Ib. to the yard. The waste rock encountered in development was trammed to the shaft and sent
the upper levels.
When the miners began to stope on any level, an upright post was rigged, and the holes pointed upward and backward. On a narrow part of the vein a cross bar was often employed,
which enabled the muckers to tram beneath from another part of the level, while drilling operations were being prosecuted. Whenever convenient, however, the miners prefer to rig upright, as they can drill more advantageously from that position. As they climbed higher on the vein, hitches were cut in the foot-wall, and stulls were put in from foot- to hanging wall. One end was fitted into the hitch, and the other end cut with such a bevel that it fitted against the hanging wall, which had been previously faced if necessary. (See Fig. 65.) The greater the weight coming on the stull, the more securely it would remain in place. These stulls were placed tightly in position, and wedged if necessary or possible. If there was any liability of their being knocked out by blasting, a hitch was also cut in the hanging wall. Stulls were used to form floors to work from at intervals of nearly 20 ft., and such a distance apart horizontally that the lagging placed upon them would not be broken by the blasts above. They were also put up against any bad ground that required them. The lagging used on the stulls consisted of round poles, and plank chutes were run up the stope at convenient intervals.
An idea of the stope and chutes may be gathered from Figs. 64 and 66. A cross bar and stage is shown in Fig. 64, but usually most of the work is done from the broken ore resting on the stulls, and an upright post is rigged, either on this ore or on benches on the foot-wall.
But where the orebody widened, stulls could not be used. Here the stope was started by enlarging the drift to the total width of the deposit, and a face obtained right across the vein. In one case the width varied from 40 to 80 ft., and, as a back or roof of this size would be dangerous to work under without some support, the timber had to be quite close to the face. When the muck was removed mud-sills were laid down, upon which the sill posts were erected. These sills were carefully placed, and tamped with fine dirt. They were braced apart by cross ties, and had a length of 10 ft. 8 in., or two sets. The framing and manner of laying them is shown in Fig. 67. At first the sill floors were not planked over, but later it was seen that a plank floor was economical to shovel from, as often there would be rock tumbling down, or breaking through from the floors above.
neously. This meant that the rate of advance was very rapid, and difficulty was experienced in keeping the timber close enough to the face. Two parallel tracks were laid to remove the ore, one along the foot-wall side and one along the hanging wall side, and a large gang of muckers and timbermen became necessary. When the sills had been laid down square sets were erected upon them, and securely braced or spragged. Spragging a set of timber requires considerable experience on the part of the timberman. Spraggs are pieces of round lagging, cut square at each end and of varying length, and placed between the ground and
the caps or ties, as the case may be, and securely w^edged. They serve to keep the sets rigidly in their proper position, and thus prevent them from falling down during concussion after blasting. The details of the square sets are shown in Fig. 68. These were at one time framed by hand, but now a framing machine does the work. The sets are shown in position in Fig. 69. This is a view of a section across a rather narrow part of the vein. One post on the foot-wall is placed in a special manner to avoid the necessity of cutting a large hitch in the rock, which is very hard. A hitch is often made when it can be cut without too much trouble. On the hanging side an extension cap is shown,
no hitch or support being made for the end of it. The top " butt " cap on the hanging side is supported at the end by a heavy pole instead of a post. The plank floor, lagging and spraggs are shown at the top.
The posts used in the Le Roi ranged from 12 to 24 in. in diameter, the caps 12 to 15 in., and the collar braces or ties somewhat smaller. In the old days it was the custom to cover the caps
with round lagging, 16 ft. long and up to 7 in. in diameter. They thus reached over three sets, but were difficult and awkward to handle, on account of their length. The lagging was then brought to the mine in lengths of 20 ft., and they were sawed in half on the surface. A double tier of lagging was used, one tier being laid on the caps and the other at right angles to them. Still later in the history
of the mine 3-in. planks in 5-ft. lengths were laid on the caps, and a few rough holes placed on top of them, to prevent the plank being broken by the blasts. These planks were spiked with one spike in each end, and served to stiffen the timber considerably.
When the excavation on the level had advanced a reasonable distance, say about 60 ft., another floor was started on top of the timber. Overhand stoping now commenced and rock or ore was broken much more readily than on the sill floor, as it had a better chance to break, there being more free surfaces. Holes
were drilled in a face about 7 or 8 ft. in hight, and placed so as to bring the ore down to the best advantage, viz., enough holes were drilled and enough powder used to break the ore to convenient size for economical handling. If it were broken too fine it would take too long to shovel into chutes, while if it came down in the form of large boulders it was necessary to blast. The sizes most conveniently handled were lumps weighing from 25 to 50 lb., which could be rapidly and easily thrown or pulled into chutes. The holes were generally drilled in the direction of the vein or orebody, and not across it, the depth being about 7 ft. At each set-up the miners moved across the face from foot to
hanging, or vice versa, as the case might be. In this way the muckers cleaned out the broken ore behind, and, as soon as there was room, the timbermen proceeded to put up the timber.
every third set at most. The bed pieces were made of 8xlO-in. timbers, placed at proper slope for the rock to roll down, one end being on the collar brace, and the other supported by a cross piece inserted between the posts, and high enough to enable the one-ton ore cars to pass beneath. Figs. 70 and 72 show a front
and side view of a chute respectively. The chute door or gate consisted of a semicircular sheet-iron plate, with suitable stiffening to prevent deformation, and a lever attached by which to operate it. By means of these chutes properly made, and with dry ore, the car could be filled in a very few seconds.
As more floors were constructed above, the chutes were carried up the full size of a set, by spiking plank 8 ft. 8 in. in length on the caps and collar braces. To bring them closer to the ore, as in a large stope, the chutes were expanded to take in two, three, and even four or five sets. (See Fig. 71.) The chute planks were all placed vertically, and where it became necessary a bottom of short lagging was made for the rock coming from above to fall upon. A stiffening was made for the chute planks by a cross brace between the posts, half-way up and well spiked. In a wide stope, two rows of chutes and two lines of track were constructed. By this means the muckers were enabled to get the ore into the chutes without being compelled to throw it far, or to use wheelbarrows or any other device.
While any level was being developed a winze was sunk from the level above to provide ventilation. These winzes were always located in the stopes, and provided a sort of chimney by which the smoke had a chance to escape. They were also used as an easy route by which timber could be lowered to the upper floors, and later, when the ore had been all removed, or nearly so, waste rock was run in through them to fill up the stope.
As more and more floors were attacked and carried forward, more faces were worked simultaneously. Care had to be exercised in regard to approaching too near the front line of timber. The blasts might jar the timber, and possibly cause it to throw forward a few inches, even if they would not knock it down. When square sets have been disarranged in this manner, it is a very difficult matter to force them back into position again. I have had occasion, as a timberman, to use jack-screws in cases of this kind, and to spend considerable time on work which, with a little more caution on the part of the miners or the management, would have been unnecessary. One machine at a face and one machine at every other floor appeared to be a good method. This allowed the men of the timber gang to put up a line or two of timber on the intermediate floors, and they were not interfering with either the muckers or miners.
An idea of the method of attack in a stope may be gathered from Fig. 73. In this view, however, I have unfortunately shown the limit of advance on each floor rather than the actual working condition. As illustrated in the diagram it would be necessary to carry the lower faces ahead to allow a chance to work on the upper ones.
As the floors became more numerous and farther and farther away from the winzes, some method had to be adopted to get the timber into the stopes more easily, quickly and economically. An excellent plan was introduced in the Le Roi in the large stope on the 700-ft. level. A track was laid the full length of the stope
on the first floor above the level, up out of the way of the tramming tracks, and a truck carrying a small air hoisting engine placed on it. From the drum of this hoist a manila rope was carried up a special timber chute, over a pulley on an upper floor, and then down the chute to the level below. Here the timber was attached with a hook and half hitch, and hoisted to any floor desired. An idea of this arrangement may be gathered from Fig. 73, in which one timber chute is shown beside an ore chute. The timber chutes were made of 2-in. planks, spiked to the collar braces, and inclined with the vein. They were erected every 80 ft. or less, and were convenient for hoisting drills and
machines, as well as timber. The timbers could be readily dragged to any place desired by means of the " come-alongs," which were a pair of hooks attached to the center of a small pipe 3J ft. in length. A man on each end of this pipe could drag a post anywhere over the floor.
The ore was not sorted in the mine, but sent to the surface to be treated there. It was trammed to the shaft and dumped into large pockets from which the skips were loaded. The tracks at the shaft were laid directly over the pockets, and the ore was dumped from the car between the rails, or at one side of them. These pockets were capable of holding a good many tons, so that, if anything happened to the hoisting apparatus, the trammers could still work away, and fill the pockets. In the new shaft, which was put through by means of raises from each level, pockets were made with a capacity of about 200 tons.
From this somewhat detailed description it will be seen that a great deal of timber is used in this mine. The timber is not used merely to hold up the hanging wall and roof, but principally to furnish a convenient method of reaching all the ore, and to prevent loose slabs and boulders from dropping on those who must work beneath. The workings are kept closely timbered, and thus liability of accident is reduced. No staging is needed in rigging machines, the muckers have a good floor to shovel from, and chutes are handy and convenient, more so than could possibly be the case in any other mining method.
By this system all the ore is taken out between levels. The sills of one level are caught up from beneath, and timber connections made with the level below.
When a stope or level is worked out the only timber saved is the rough lagging and plank flooring, which is readily torn up and used again. Waste rock from development work in other parts of the mine is dumped down, and the old stope gradually filled up. This rock is brought up from the lower levels on cages in the new five-compartment shaft. No great attempt is made, however, to fill the stopes.
only is the deposit of immense size, but the grade of the ore is much lower, necessitating a much lower cost of extraction, in order to mine it at a profit. To accomplish this a large output is essential, and cheap and rapid means of handling it, from breaking the ore down until it finally reaches the smelter. The ore is mined in three ways in these deposits:
The open cut was on a level with the railroad track, and a tramway was built with an incline to enable a small hoist to bring the ore up high enough to dump into the railroad cars. This is quite an ordinary method and needs no further comment, the ore being broken down in the usual way. Later, however, when a considerable excavation had been made, a steam shovel was used, which handled rock of much larger dimensions. Boulders too large to go into the bucket were picked up by means of a chain. They were loaded either directly into the shipping cars, when the ore was crushed at the smelter, or into small wooden cars, and taken to the crusher first by horses, and at the present time by a small locomotive. Three steam shovels are now at wrork for this company in their low-grade orebodies, and they will tend greatly towards solving the problem of decreasing the cost, and, at the same time, largely increasing the shipments.
The milling or "glory hole" method also applies more particularly to the Knob Hill than to the Old Ironsides Mine. It consists essentially in driving a tunnel into the deposit to be excavated, as low as can be conveniently worked without the sides caving in, and then a raise to connect with the surface. At the bottom of the raise a very substantial chute is constructed from which the ore can be readily withdrawn into cars. Operations then begin on the surface and the ore is milled or broken down, being blasted into the raise. Suitable faces and benches are soon established, and a better command obtained of the size of the rock going down the chute or raise. Very deep holes are drilled and very heavy blasts set off, thus breaking the ore quite rapidly and economically. The benches are arranged in such a manner that a great amount of the rock rolls down into the chute, which is always partially filled, without much handling.
The advantages of this method are as follows: practically no expense for timber; no bad air to work in and hence no time lost ; few drill holes needed and comparatively little powder used ; the ore handled mostly by gravity.
in of the sides.
On the deeper levels of the mine the usual method of underground development was carried out. The system of mining the ore was very similar to that in vogue in the Le Roi, which has been already described. The timbers, however, were stouter, and the method of lagging was different. In arranging the lagging
the object was to place it in such a way that the broken ore could be rolled into the chutes with the least possible amount of shoveling. To accomplish this, lagging about 10 ft. long was laid on the caps, close together, and, if the poles were weak, perhaps a double layer. A space two sets square had the poles laid parallel, and the adjacent squares were poled at right angles to these. The caps and collar braces were of the same dimensions, hence it did not matter which way the lagging was arranged. In this way the poles had a good support at both ends, because they reached well over two 5-ft. sets. When it was desired to remove the muck, all that was necessary was to move a pole so that the ore could drop through. As it rolled down, with the aid of a pick or bar, another and another pole could be rolled from beneath it. In this manner the writer has rolled into the chute 40 or 50 tons in four or five hours. Any very large boulders, of course, were smashed with a sledge hammer. Fig. 75 is meant to show the arrangement of the lagging. It is a plan of the floor immediately under the ore to be mined, while Fig. 74 is an elevation of the same.
FIGS. 76 AND 77. — CHUTE ARRANGEMENT, OLD IRONSIDES MINE. A special method of chute building was adopted here. Above the first floor they were built in the shape of a long trough-like
V running from one brace down and across to the next. Poles were used for this work, and spiked securely to the square sets. Figs. 76 and 77 show the arrangement of the chutes in elevation and plan. At convenient intervals an outlet was made, and between the chute gates the ore was allowed to pile up a little. The ore was trammed to the shaft in ordinary one-ton cars, and hoisted to the surface on a cage through a vertical shaft.
BALTIC MINE, BALTIC, MICH.
The method adopted in the Baltic is peculiar to this mine, and is not used, as far as I am aware, at any other mine in the copper country. It is a simple system of walling up each tramway with waste rock, thereby keeping a roadway open, and filling in above with the gangue and country rock, as convenient. In this way the expense of putting in timber is minimized, which is offset by the walling and filling. The method is only applicable when the vein carries waste, or when waste rock is easily and cheaply obtainable.
The material mined is native copper, which occurs in a vein of lava rock both as "shot copper" of varying size scattered throughout the rock, and as "mass copper," which is solid copper of more or less irregular shape. The pitch of the vein is about 70 to 72 deg., and the width varies from 20 to 50 ft. Parts of the vein are more or less barren of copper, and this rock, called "poor rock," is picked out by the "copper pickers," and forms a good part of the filling.
The vein was opened up by shafts and drifts, and when stoping began, the drifts were widened out to the full width of the vein. After the copper rock was cleaned out from the face, the poor rock was taken back in cars, and shoveled to one side. When the "wallers" had enough rock to start on they began and walled it up on each side of the track, leaving a space of 7 ft. for a tramway. The walls were made about 7 ft. high, and heavy stull timbers laid on them as caps. These caps were placed about 3 ft. apart and covered with cedar lagging, so that no rock could come through. (See Fig. 78.)
At intervals of about 40 ft. spaces were left for chutes on one side of the track. They were built up with rock and had a timber margin for planks to be spiked to. In the bottom of the chute flatted hemlock timbers were laid, and a heavy sheet-iron plate
was fastened to them with drive bolts. The bottom of the chute was made flat because very large boulders were handled in it. For a gate a spout was used, one end of which was raised and lowered by means of a long, stout lever. The copper rock thrown
drilling with machines and blasting in the usual manner. The rock broken down was picked over by the copper pickers, the copper rock being thrown into the chutes, and the poor rock thrown back to fill up the excavation. As more and more filling accumulated, the chutes were carried upward in the form of a hole 5 ft. square, by means of heavy cribbing flatted at the ends and spiked. (See Fig. 79.) Sometimes the pickers needed wheelbarrows to get the rock into the chute or "mill."
In stoping, a good breast was carried along, and heavy holes drilled, since no damage could be done by heavy blasts, though it was not advisable to shatter the roof too much. As the room grew in hight the back got farther and farther away from the filling. This necessitated the use of long posts for the machines and staging for the miners to work from. The idea, of course, was to work as much as possible from the top of the broken rock, but as there were 100 ft. between levels, and not a very high percentage of poor rock, it became necessary to cut out the foot- or the hanging wall to fill in, and thus reach the back. This should always be done after the copper rock has been picked out, as otherwise much poor rock would be mixed with it. An attempt is made to convey an idea of the stope in Fig. 80.
This method is supposed to take out practically all the ore, and the only use made of timber is to crib the chutes, and cover the tracks. The vein rock is quite tough, and, with a slight arch in the middle of the roof, there is comparatively little danger from overhead. The greatest difficulty to be encountered will be in making connections between levels. Here the filling from
the level above will run down and mix with the copper rock below. Taken altogether, however, this is an excellent method of mining, and has given the Baltic people satisfaction up to the present time.
The Atlantic vein is similar to the Baltic, though it only averages about 15 ft. in width, and it does not carry so much copper. This rock is not picked over, but the total product
When the levels have been opened up the miners take contracts to stope out the pay rock. Each contract includes a part of the vein 99 ft. in length and extending between levels, which are about 85 or 90 ft. apart, and the price is paid on a basis of at least a width of 15 ft. The contractors first run a drift to the end of their ground and commence stoping, taking out enough rock to put in the stulls to protect the level for tramming.
of about 70 deg. to the horizontal, thereby leaving room for a track between the stulls and the hanging walls. (See Fig. 81.) At the same time they were quite steep to prevent them taking up more weight than they could safely bear. They are covered with lagging, which prevents the muck from coming down on the track. When this line of stulls is finished, stoping is commenced higher on the vein. The miners keep rigging up on the rock they break and it is trammed out from below when they are crowded for head room. In this way they are always close to the back, and work to the best advantage. They work up to within 15 ft. of the level above, and then, as the rock is withdrawn, the timbermen place stulls wherever they are needed to support the hanging, and make it safe for the muckers below. The pillars left constitute the floor of each level.
This method furnishes one of the cheapest and best methods of getting out stamp rock in the copper country. The width of the vein, its regularity and pitch or dip, make this a peculiarly valuable method to the Atlantic Company. Without it the mine would probably be operated at a loss, as the copper values do not exceed 25 Ib. per ton of rock.
Coming now to the iron country of Michigan we find a somewhat different order of things. Here we do not have the ores in regular well-defined veins, as is the case in the copper country. On the contrary, the ore occurs in blankets or deposits of more or less irregular shape, and the sustaining power of the adjacent rock is a far more uncertain quantity. The ore itself varies a great deal, some being soft and capable of caving, while much is hard, and a caving system could not be adopted. Some again is intermediate between hard and soft ore, and a combination of a caving system with some other method becomes a necessity.
BARNUM MINE, ISHPEMING, MICH.
This is a hard ore mine producing a hard hematite. The system of mining is simple and inexpensive, although about one-third of the ore is left for pillars. The levels are from 40 to 50 ft. apart, and after being driven, raises are run up to the level above at convenient intervals. When the raises are completed, the miners begin at the top and mill the ore down the raise in a manner similar to the "glory-hole" method already
described, except that the work is, of course, underground. They work from convenient benches and gradually cut out large chambers. Care must be exercised in scaling any loose rock from the roof while the men are close to it, because when they get lower down the roof will be out of reach. Wherever necessary, pillars are left 22 ft. square, one being as nearly as possible directly above the one below. Machines and tripods are employed, and the rate of drilling is slow, varying from 4 ft. to 15 ft. of hole per shift. The ore is also hard to break, and a 50-per cent, dynamite is used. There are no pockets in the mine, and the cars are hoisted to the surface by a single-compartment shaft. As the method at the Barnum is so simple, little more need be said; suffice it to say that the method is very wasteful of ore, because such a large percentage of it is left in the mine.
The ore from this mine was also fairly hard and a similar method of mining was adopted. Levels were run from the shaft to the orebody at intervals of about 60 ft., and a drift run along the foot- or hanging wall as desired. From this drift raises were driven every 50 ft. to the level above, thus making a passage for timber and ore. At 15 ft. below the upper level the raise was enlarged into a stope or room, and made of such a size that it would be safe to work in, dividing pillars being left on each side. The ore was thus removed down to the level below, and pillars were left extending across the orebody.
When the rooms had all been excavated in this manner the robbing of the pillars began. The pillars were usually 25 ft. through, and they were undercut on one side to a distance of
about 9 ft., and right across the vein. The timbermen then built cribs of timber 8 ft. square in this space, and as many as they had room for, leaving a space of 3 ft. between them for a passage. These cribs were built right up to the back, wedged down and filled with rock. (See Fig. 83.)
The next step was to undercut another 9 ft. and treat it with timber cribs and rock in a precisely similar manner. Finally the last portion of the pillar was removed and cribbed, and the pillar rested now entirely on the crib supports. The stopes on either side of the pillar were then filled with loose rock to the level of the top of the cribs, and also in between them, a passageway, of course, being left for tramming.
The pillar having been undercut to a hight of about 8 ft., another slice is removed in much the same manner, at a higher level. Mills become a necessity in order to let the ore down through the rock filling, and these are made of round poles and placed at convenient intervals. As the pillar is attacked at a
by this method it is possible to remove practically all the ore.
The filling used is obtained from two sources : part is furnished by the ordinary development work, and the remainder is obtained from the dump of a neighboring mine. It is loaded into railroad cars, and dumped directly down a raise for that purpose. This raise is tapped where desired by a rough chute, and the rock trammed in small dump cars running on tracks laid on the filling. These tracks are readily moved laterally, so that the rock is conveyed to the place desired without very much shoveling being required.
In parts of the mine where the orebody is of such nature that ore pillars are not necessary, a method of overhand stoping is prosecuted. This operation is followed directly by the filling, the ore being mined out and the excavation filled with waste rock. Where the roof is not good, cribs are built on the filling to support it.
timber erected.
The methods of mining at this mine are therefore somewhat special and varied. The cause of this variation is due to the fact that the orebody changes from place to place in hardness, width, and accessibility.. In some parts of the mine it is hard to introduce the filling, while in others it is a cheap and efficient adjunct in extracting the ore. Wherever used it forms a compact and satisfactory substitute for timber, which, to perform the same duty, would be quite expensive.
Here we have a mine which was formerly covered by Lake Angeline, a body of water of about 100 acres in extent, and 50 ft. deep in the deepest part. The water was pumped out by means of powerful pumps, and the lake bed became comparatively dry. On the margin of the old lake shafts were sunk, and the mining of the large deposits of soft ore was begun. The ore, being a soft red hematite, was very easy to break down, but it was impossible to have large chambers excavated, because of its
system of mining was soon inaugurated.
Haulage ways were, as far as possible, made in solid rock. Then raises were driven to the top of the ore deposit, at intervals of from 60 to 100 ft., and cribbed with two compartments, one for a ladder road and the other for ore. Sub-levels were also made to facilitate operations. The ore was loaded into cars holding about 2J tons, which were attached to a "bull-dog," and taken to the shaft in trains of six or seven. The bull-dog was
operated by a cable, each end of which passed around a drum run by compressed air. One engine was located at the shaft and the other at the end of the haulage way. At the shaft the cars dumped directly into the skip, and were moved up to, and away from, the shaft by hand. The idea of the bull-dog is to facilitate coupling, the cars being connected to the bull-dog instead of directly to the cable.
When the chutes were completed a "top-slicing" scheme was begun. A drift 8x8 ft. was driven parallel with the deposit, and timbered with square sets. Theso sets consisted of legs and caps
as shown in Fig. 84, and were placed 4 ft. apart. At the raise it was important to have rather stout timber, because here the timber was expected to stand the longest, and was therefore subjected to most pressure. Farther from the raise or chute the timber was much smaller, 6 to 12 in., and the caps were covered with light lagging. The caps, as a rule, were a few inches larger in diameter than the legs.
The second step in top-slicing is to begin at the farthest end of the drift and cross-cut to both foot- and hanging walls. These drifts are also 8x8 ft. and are driven parallel, and one after another, until the whole area is excavated, that around the chute being taken out last. The same procedure is followed on the opposite side of the chute. The floor is then all lagged over to prevent mud, gravel, etc., from mixing with the ore when subsidence takes place. The legs of the sets are blasted out and the overlying burden is lowered, as a consequence, all over the area in question.
Mining below this is now done by the real caving system. The miners drop down 12 or 15 ft., depending on the hardness of the ore, and run a drift as before. Side rooms are run to foot- and hanging walls, and when these are reached the most remote sets are blasted, and the roof is caved in. By working as they retreat practically all the ore is removed from beneath the lagging above, only one set usually being blasted at a time. Sometimes several rooms are worked out before caving, but it is unsafe to leave them for any length of time. It is deemed advisable to finish one room before beginning another. In this manner a whole slice is taken out, and overlying debris or " gob " is lowered once more. Then a drop is made for another and another slice, until the bottom of the deposit is reached.
Contrary to what might be expected this is a comparatively safe method of mining. The men work near the back all the time, and, should there be any danger, warning is given by the gradual crushing of the timber. No large rooms are excavated at any one time, and there is practically no danger from this source.
The system is also cheap, comparatively little timber is used, and even that is of an inferior order. Very little powder is necessary, and there is not much drilling done. Holes are drilled with machines, augurs, or hammer and drill, as the particular hardness of the ore may make advisable. The cost of mining is low, and
contracts run at $4.50 for an 8x8-ft. drift per foot of advance. The miners make from $55 to $60 per month after deducting all expenses for powder, caps, fuse and candles.
In the Queen mine, as its name implies, we have a fine example of systematic iron mining. The orebody is large and fairly regular and lends itself particularly well to methodical development. The ore is not very hard, and it is not soft enough to cave, as in the Hematite. A special method has been adopted and seems to answer the purpose very well. The system in vogue starts out as a square-set system and develops a caving system as the wrork proceeds.
The orebody is in the shape of a lens, and dips to the north at an angle of 38 deg., and also pitches to the west at 45 deg. Six shafts have been sunk, the first three on the eastern side being now worked out. From the shaft a well laid out system of haulage ways has been driven, special attention being given to prevent interference of cars with timber, and vice versa. The timber can be handled on one line of tracks often at right angles to the haulage tunnels. The main ore drift has been double tracked, and an endless cable picks up the loaded cars of ore as desired, and takes them to the shaft. The cable is operated by an engine at the shaft with a special device to keep up uniform tension. The cars are attached to the cable, which is always moving, by hand, and are detached automatically when they reach the shaft. They are dumped into pockets and sent back by the cable on the other track. The expense of operating this haulage system is only J cent per ton.
Coming now to the mining system proper, we find a face of 3 sets wide or 25 ft. carried forward, and timbered with good substantial square-set timber. Then parallel to this another similar face is driven, but with a pillar 5 sets, or 40 ft., left between. Cross-cuts are also run, blocking out the pillars into squares. (For elevation and plan of stopes and pillars see Figs. 85 and 86.) At the same time these faces are being worked on the level, another and another slice is stoped out and timbered above. In this way the orebody is honeycombed to the top of the deposit, pillars and rooms alternating throughout the level.
After the ore has been excavated in this manner .the work of taking out the pillars and caving begins. A raise 8x8 ft. is now run up through the center of the pillar, and timbered with the usual sets. Thus between the center set and the timber in the rooms outside there is a distance of two sets. The top of the pillar is taken out to the depth of one set, and caps of double length are used to connect the center with the outside sets. Negaunee, Mich.
is done on the four sides, and the top heavily lagged. The ore is then worked downward, using the long caps at each step, but without lagging. The material of the pillar is readily broken up and sent down the chutes in the outside sets; in fact, it is the most rapid method of breaking ore in the mine.
up, a flooring of poles is laid, except where there is a rock floor, and every second leg is blasted out, thus bringing down the whole mass of timbers as well as the roof.
A system called "scramming" is used to mine on the level below. The level is divided into 50-ft. squares, and in each a raise 4x9 ft., in two compartments, is run up to the lagging above, the levels being 85 ft. apart. Starting 9 ft. down, a drift is driven from the raise 25 ft. each way, and timbered with light sets. The ore is shoveled directly into the chute or a wheelbarrow is used. A second drift is run beside the first, though not always, and the bottom is lagged over. Then the legs are blasted, and the overlying debris caved, as in the Hematite mine. The process is repeated until the 2500 sq. ft. is lowered 9 ft. The miners now drop once more, and repeat the operation, and so work down to the level.
While work is progressing in the drift the timbers begin to crack, which is a good sign, because it shows that the mass above is slowly settling. If the timbers do not show that they are supporting great weight the debris has become "hung up," and is liable to come down at any moment. Seeing this the miners either blast it down, or get out of the place. When the timbers show pressure the workmen are safe, as the mingled rock and timbers settle very slowly, an inch or so a day.
the surface immediately above.
In the foregoing description of these several mining methods, little attempt has been made to go into the minute details of the various schemes presented. The systems taken up represent the actual practice, in their most essential features, of underground work in western America, outside of coal mining. Much more might be said in regard to many matters connected with them, such as their comparative expense, the percentage of ore recovered, their suitability to general conditions, etc. To go farther into these matters would make the paper unduly long. No references have been consulted, as I have gathered all the data at first hand.
practice to have sills of the level below, in the sme vertical plane with those above, surveyed and laid down accordingly, but in carrying up the sets 100 ft. it was almost impossible to go up straight enough to have post match with post properly. They would come either one side or the other of the vertical plane and be out -of plumb perhaps a foot or two. Unless they could meet the upper sets exactly, it did not really matter whether the sills below were surveyed or not, except to get the general direction of the timber. The sills of the upper level were caught up by the cross timbers, reaching two or three sills. Little attempt was made to have posts of lower sets directly under posts of upper sets. Bulkheads were often used and the rock must be blasted out carefully and not too fast.
Mr. Parlee also said that the square-set system was used wherever the ore was too hard to cave without it. It was not the intention in the paper to discuss all the methods used in each mine, but only those especially valuable. Different methods might be used under different conditions.
The chairman remarked that what Mr. Parlee had said about the impracticability of exactly connecting the timbering of adjoining levels held true in all parts of the mining world. The theory was that posts in successive levels should come under one another, and in certain mines that he had visited more or less successful attempts had been made to do this, but in most cases the method described by Mr. Parlee had to be adopted. As he had said, the main thing was to see that the vertical lines were kept true and that the timber was put in substantially. Sometimes comparatively heavy bulkheads were used. It was, of course, possible to survey with sufficient accuracy to have the posts placed perfectly plumb and in line, but this was too troublesome, and it was still more troublesome to erect great masses of sets exactly in line and plumb, especially when, as was frequently the case, there was movement going on in the orebody or hanging wall.
BY C. ST. G. CAMPBELL
IN the following paper it will be necessary to depart somewhat from the subject proper and give a brief description of the location of the mine, the method of mining the ore, the management, etc.
Section 16 is essentially a hard ore iron mine, situated threequarters of a mile from Ishpeming, a town fifteen miles from Marquette, on the south shore of Lake Superior.
The mine is worked chiefly for hard ore, there being three large lenses, each of a different grade, according to the percentages of iron and phosphorus contained. There are also two "pockets" of soft ore, which is locally known as "hematite," but after mining these pockets for some time, it was found that the ore was too high in phosphorus to compete with the soft ores of the surrounding mines. So, for the present, at least, the mining of it has ceased.
The hard ore is found with a foot-wall of decomposed diorite, resembling soapstone, and a hanging wall of quartzite or jasper. A great dike of diorite cuts across the deposit and makes the formation somewhat irregular. The three lenses dip at an average of 70 deg. with the horizontal. They have an east to west strike and vary very much in their dimensions, ranging from 10 to 700 ft.' long. The dimensions of the so-called "south vein" have not yet been determined, as it reaches below present operations.
The method of extracting this hard ore is as follows: At intervals of 60 ft., levels are run out from the vertical or hoisting shaft until the ore is reached. A tunnel is cut along the length of the lens, clinging to either hanging wall or foot-wall as the
case may be. Raises are then made every 50 ft. to the above level, or nearly so, a back of 15 ft. being left to make tramming safe. Through this back a small hole is cut to let down timber, also for the purposes of ventilation, etc. When first cut, these raises are 9 ft. in diameter and are afterwards widened until the dividing pillar is as thin as is consistent with safety, say 15 ft. in the average.
Projection of 2d and 10th levels. The levels are 370 ft. apart.
width of the vein, the shift boss using his own discretion as to the method employed. Finally, however, the stopes or raises are filled up with rock, leaving a timber tunnel for the passage of trams on the level below. Mills are also built and rock filled in around them, a process which will be described more fully later. The pillars are then mined out and their places filled in with rock. In this way all the ore is secured.
The hematite, so called, is mined by the " square-set " system, which consists of taking out slice after slice of the ore, the length and breadth of the pocket, and in its place putting timber in the
form of skeleton cubes, the sides of which measure 8 ft. These cubes or square sets, as they are called, are put in one at a time, just enough ore being taken out to allow the erection of a single square set. The pocket is worked from bottom upward, thus securing the advantage of gravity for the removal of the ore. All the ore is sent down by means of improvised chutes made of lagging.
The mine is at present 850 ft. deep and the shaft is still being sunk to tap the south vein. There are at present 13 levels, 12 of which open on to the shaft. The 4th, 5th, 6th, 7th and 8th levels have all been mined out even to the pillars. On the lower levels, tunneling and raising are being carried on, while on the first three levels the "robbing of the pillars" is not yet completed.
There are two other shafts, besides the one above mentioned. These are used for ventilation and shooting down the rock used for filling. These shafts, one of which is inclined, reach only to the second level. From there on, the rock is sent to the lower levels by means of mills.
For the most part, the "hard ore" justifies its name and is hard and compact, but occasionally it is of a slaty structure or full of cracks and fissures. In such places it is necessary to use drift sets. Similar protection is also necessary when drifting through decomposed diorite, locally known as "soapstone."
The proposition which the timberman has to handle now having been outlined, the respective applications of the different methods will be taken up in detail.
The timber is obtained, for the most part, from lumber camps, the farthest not being more than 20 miles from the mine. This timber is taken to the mine by rail and stocked near the main shaft. Second-class logs are used, knots and slight crookedness not being objectionable. The logs, cut into either 5J-, 8-, 10- or 16-ft. lengths, are lowered into the mine by means of chains attached to the bottom of the skip. The timbermen land them at the level station below with the aid of a rope, ship them on to a tram and take them to a timber-dock, where they remain until required. Between the hours of twelve and one on the day shift the miners are on the surface for lunch, and advantage is taken of this fact to lower timber. In consequence the timbermen remain below and take out timber, thus postponing their
lunch for one hour. Hemlock and white pine are used for the most part in the large timbering. Cedar is used for lagging. The captain is at present experimenting on hard wood. Squared timber is used only in the shaft and under certain special conditions elsewhere. In other places not only is timber used round, but also with the bark on. The life of a " stick " is very uncertain, depending upon the nature of the wood, the stress to which it is subjected, and the temperature, hence the moisture. On the 7th and 8th levels, immediately above the pumps, which are on the 9th level, the timber lasts only five months, after which it is quite easy to force the point of a candlestick six inches into the wood with the hand. This is exceptional, however. The average life of timber in the mine is said to be ten years. The timber is often crushed by the settling of ground, but there is little danger to life in this, owing to the slowness of settling.
SHAFT TIMBERING
The method of sinking the hoisting shaft is somewhat similar to that of raising a square set. A rectangular hole is stoped down to a depth of 10 ft., having a width of 10 ft. and a length of 18 ft., and in this hole is set up a double square set, 8x8x16 ft. This square set is suspended from the one above by means of bolts. It is then wedged into place and lagged between the timber and rock. The shaft is then sunk another 8 ft. and another double square set placed and bolted to the bottom of the former, and so the sinking and timbering proceeds. The timber in the square sets used is from 12 to 18 in. in diameter. Every time an advance of three sets (24 ft.) is made, the small shaft pump is lowered the same distance, so keeping within the 27-ft. practical pumping limit.
The shaft is then lined inside the square sets with 8x8-in. squared timbers, 18 ft. long, placed close to one another vertically, giving the shaft a box-like character. In each set and parallel to the ends of the shaft are placed cross pieces to which planks are nailed, thus dividing the shaft into four compartments. The center two are about twice the size of the end ones and are used for skip roads, while the end compartments are used for pipe, pumps and ladder ways. (See Fig. 88.)
at each side of the skip. These are placed vertically 6 in. apart.
Until lately much trouble has been experienced from water in the shaft. With a view to stopping this water downpour, troughs or garlands have been arranged to carry the water into pumps at depths of 190 and 680 ft. This has proved very effective.
The rock shafts are very much simpler in construction, being merely lined with rough unbarked logs built up like a crib. It is usual to hoist to the surface all rock from the stopes at the bottom of the mine and send it down again to the levels where the pillars are being robbed. Obviously this supply of rock would be insufficient. Hence carloads of loose rock are brought from the No. 1 hard ore mine and dumped down one or other of the shafts as required.
with a covering of poles resting on the caps, constitute for the main part what is known as the "drift set." The caps are chopped flat at the ends so as to set firmly on the legs. The pairs of legs are kept apart by studdles, which are poles 4 ft. 6 in. long and 4 in. in diameter, set close under the caps and at right angles to them. (See Fig. 89.) The legs are firmly spragged against the wall, and spaces between the legs lagged on the rock side. The lagging is nailed to the legs horizontally, one above the other, and the loose rock is piled in behind the partition so formed. The covering poles used are from 4 to 5 in. in diameter. These are laid lengthways, the ends of the poles in one direction of a set resting on a cap, and in the other direction resting on the ends of the poles of the preceding set. By means of small pieces of timber the back is caught up and wedged tightly. (See Fig. 90.) If the pressure is likely to be great, owing to caving in
of the sides of the tunnel, the legs are set wider apart at the bottom to ensure greater stability. At each end of a line of drift sets slanting props or "rakers" are propped against the legs to keep the whole steady when the blasts go off. (See Fig. 91.)
A single square set consists of four vertical legs arranged in an 8-ft. square, each leg being 8 ft. high. The legs of two opposite sides of this square set are held together by caps, which rest on
SQUARE SETS
the top of the former. The two other sides are held together, or, better still, held apart, by studdles, in this case 8 to 10 in. in diameter. The studdles are nailed in place a little lower than the cap. The legs and caps have average diameters of 18 and 12 in. respectively. The top of each set is covered with 4-in. poles, in order to prevent ore from coming down on top of the miners. The whole set is spragged securely when first built and thus remains until surrounded with other sets. For the sake of strength and continuity, the same two sides of a square set always have the caps. If the stope is fairly wide and high, chutes are built in so that each one is fed by five columns of sets. Twice attempts have been made to mine the hard ore by this system, but without success.
STULLS
In raising up along the lens the hanging wall is often loose, great masses sometimes breaking off, and, in consequence, it is necessary to prop the loose ground up by means of stulls. (See
measured from foot-wall to hanging wall and the stull cut a corresponding length. A socket is made for the end of the stull on the foot-wall by scooping out a shallow hole. The stull is then driven into place and fixed tightly by means of wedges. For obvious reasons, every endeavor is made to have the greatest stress along the line of the prop, though in some cases this is not at all possible. (See Fig. 93.)
In the raises on the 13th level, it is impossible to set up machines, owing to the narrowness of the lens and the steepness of the dip, except as follows: Two stulls are erected within 7 ft. of the breast on either side of the raise (8 ft. apart). On the top side, poles are laid halfway up to the hanging and then ore is pulled down behind these poles until a horizontal surface is
obtained. On this surface, which is about 6 ft. wide by 9 ft. long, the machine is set up. (See Fig. 94.) This is called a bench, and is used for 16 ft. of advance st oping, after which another one is built above it in the same manner. It is found expedient to remove the lower ones as soon as the top ones are built, to give free passage for ore.
Great difficulty is experienced in getting timber up into the raises. Owing to oversight, all the tackles are too short, so the logs have to be carried up the slope by the timbermen, who hold the log under one arm and use the other to pull themselves up. It is quite customary to do this for 30 ft. before the tackle comes into play.
TIMBEE PILLARS, OB CRIBS
The duty of a timber pillar is to hold up ground. It serves the same purpose as a vertical stull, only on a much larger scale. The pillar is made of rough unbarked logs, 8 ft. in length and anything from 6 in. to 2 .ft. in diameter, according to the weight the pillar is to bear.
A pair of such logs, 7 ft. apart parallel to each other, are laid directly under the "bad ground/' and on top of these are laid two more at right angles to the first two, the same distance apart and parallel to each other. Again on top of these are laid two more in the same way. The pillar is thus gradually built up to the back and eventually wedged down tightly by lagging and
small pieces of wood. Considerable experience is required to make a tight fit, owing to the unevenness of the ground and the tendency for the whole to shift. All the pillars are inspected every day by the timber boss to guard against any such failure. In laying one cross piece on top of another there is great tendency to roll; in consequence, notches or " joggles," as they are called, are cut in the lower log, into which the upper one fits. It is not usual to cut them more than 3 in. deep.
Wooden pillars are used nearly altogether in the robbing of the ore pillars in between the stopes. These ore pillars are about 25 ft. through from stope to stope. A space is cut out of the pillar, about 9 ft. through and the width of the lens, if the same be narrow, and 8 ft. high. As many pillars as can be are built in this space, 3 ft. always being left between them for walking roads, Sometimes, instead of making two pillars of the foregoing dimensions, one long pillar is made 16x8 ft. The inside of the timber pillar is now filled with loose rock, This rock steadies the pillar and takes the bulk of the weight when the back settles. The long pieces are called "edgers" and the shorter ones "cross pieces." When these pillars are securely wedged against the back, the machines are set to work again and a space similar to the first is mined out and treated with pillars. This process is carried on the width of the vein and breadth of the ore pillar until all the ore in the latter rests on timber. The stopes on either side are now filled with loose rock to the level of the top of the timber pillars, likewise the spaces in between the pillars, and the process of mining out and timbering proceeds as before, the timber pillars having as their floor the tops of pillars of the slice below. The level of the rock in the stopes is kept up to the bottom of the timber pillars.
The purpose of a "dock" is to hold back rock. It is used where loose rock is pouring down upon the track and so stopping the trams; likewise in filling the stopes, as before mentioned.
The dock is a simple cribwork like the timber pillar. Rock is dumped inside and then the running rock is allowed to bank up against it. The double length 16 ft. is more usual than the single in docks. To save timber and labor the inside edgers are
sometimes done away with, the ends of the cross pieces resting on the outer edger and on the sloping pile of rock. As the work progresses, a couple of men shovel down rock and thus keep the level of the rock up to the required hight for the cross pieces to rest upon. (See Fig. 95.)
In filling the stope a tunnel must be left for the trams, hence on both sides of the track docks are built to a hight of 8 ft. and are filled with rock in and behind. A double layer of covering poles, 4 in. in diameter, is laid across from one dock to the other and the whole is filled over with rock. It is considered advisable to leave ample space overhead in the tunnel, because the pillars sink sometimes 3 ft. or more, owing to the settling of the rock filling. It is found that the hanging wall side settles much faster than the foot-wall side.
Mills are used in robbing the pillars, to convey to the level below the ore which is mined. A mill might be called the converse of a timber pillar. It is cribwork built up like the other, but is not filled with rock. Instead, the mill is covered with cedar lagging on the outside and filled around with rock.
chute.
The mills are made either single or double, being 5 ft. 4 in. by 5 ft. 4 in., or 5 ft. 4 in. by 10 ft. The latter is the more usual form, one compartment being used for a ladder road, the other to dump rock down.
Filling pieces are used in the partition of the double mill to prevent rock from coming into the ladder-road. (See Fig. 96.) There is an enormous wear and tear on the mills, due to the falling ore, hence the soundest timber is used. Hemlock is preferred, owing to its toughness.
The life of a mill is very uncertain. On an average, a mill lasts three months when it is worked night and day for six days each week. What then happens is that the pieces of ore cut through the cribbing pieces, attacking all sides of the mill impartially. To repair 4 ft. x6 = in. iron plates for 20 ft. down and then with 3-in. planks. The wear and tear depends upon the hight of the mill, the kind of timber and the nature of the ore. The diameter of the pieces of timber is from 10 to 18 in.
It is customary to give an inclination of 15 deg. to the vertical in the mill, in order to break the fall of the ore and so save the bottom boards of the chute, and, incidentally, insure safety for trammers.
The chutes that empty the mills are 2 ft. wide at the smaller end, widening out to 4 ft. and covering all the floor space of the mill. They have an inclination of 45 deg., the mouth is 4 ft. 6 in. from the track and protrudes 1 ft. into the tunnel. All chutes are made of 3x8-in. planks. Spaces are cut out of the cribbing pieces of the mill to permit the chutes to be made. Chunks of ore, 8 in. or less in diameter, can get through the chute; anything larger than this sticks and has to be "block-holed." This is to be avoided, because the blasting soon destroys both mill and chute. (See Fig. 97.) In the case of the square chute, the ore
as a sort of chute.
The ore is kept back by means of boards fitting into slits in the sides of the chute. Sometimes it is hard to send these planks into place and so complications arise.
STAGING
When it is necessary to take ore 'off the back of a high stope, the drilling machine has to be raised within a few feet of the place to be mined. This is done by means of staging. A stage consists of three ladders, each at the apex of an equilateral triangle of 5-ft. side. The ladders are inclined outward and are wedged against the back. Planks are then placed on the rungs of the ladders, so as to make a platform. The machine is then set up on this platform. At the best it is a very shaky affair and cannot be carried to any great hight, 15 ft. being considered a very good hight for the platform of such a stage.
LADDERS AND SOLLAES
In this mine the ladders all have an inclination. This inclination tends to make climbing much easier and safer. The poles of the ladders are made of 3x5-in. white oak scantling. The rungs or "staves" are either of white oak or iron, the former being 1J in. in diameter, the latter f in. in diameter. Under the calked boots of the miners they are soon worn through and are in many cases left too long for safety.
The shaft ladders are in sections of 20 ft. The sollars are 15 ft. apart, with a hole in each large enough for a man to get through with ease. The end of the ladder protrudes through the hole.
The ladders in other parts of the mine, in the other raises, for instance, are much longer, and are made by bolting together two or more 20-ft. lengths with scantling, on the outside. The ladders are always spragged securely to prevent shaking.
The sollars are a great means of safety and prevent many serious accidents, especially in the shaft, where it is now impossible to fall more than 20 ft., in the ladder road, that is to say.
Log pike.
The foregoing information was obtained at Section 16 mine last summer. The figures given are, to the best of my knowledge, accurate. However, the character of the mine is such that rules of thumb are few and far between. When a problem presents itself, it is solved according to the ideas of the particular shiftboss in charge, subject to the approval of the captain, who makes his rounds every morning.
THE support most frequently employed for preserving the integrity of vertical and inclined shafts consists of a rectangular frame of timber, the parts of which, proportioned to any required dimensions, are so fitted together at the joints as to form a connection that will weaken the timbers forming the " set " or frame in the least possible degree. Many methods of framing the joints have been employed and many forms of joints used, but those described below are now almost universally accepted as affording the greatest possible strength while being at the same time of comparatively simple construction. Their present general use may be said to represent a survival of the fittest. (See Fig. 98.)
The connecting joints between the different timbers that are assembled to form the shaft set are made up of various shapes of the tenon and mortise, the gain and the miter, used either singly or in combination, which are the basis of all joint framing, however much they may vary from their simple forms when employed as shoulders, squared or beveled; aiid all other contrivances whatsoever for bringing together from two or more directions the parts of the set and properly connecting them at such points. In general it may be assumed that the pressure thrust is directed from without inward toward the center of the shaft, and it is for the purpose of opposing or resisting this pressure that the shaft set is designed. This hypothesis, however, is true only in part ; for through causes that are sometimes known, but often are unknown, the action of this inward pressure becomes deflected from a normal direction to one that bears upon the frame at a divergent angle, and this is especially true with regard to inclined shafts in certain formations. In such cases the remedy is usually applied whenever it may be necessary, subsequent to the timbering of the shaft.
The several parts of shaft sets are named with regard to their position relative to the shaft. Primarily the frame consists of the timbers of the rectangular set proper, together with those distance pieces, called "posts/' which retain it in position at a required distance from the adjacent sets above and below. The rectangular set of the frame is made up of jointed timbers that are known as "plates." While all of the plates of a set are properly wall plates, yet there is a distinction usually made in that the longer pair, those paralleling the greater axis of the shaft, are named " wall plates " in contradistinction to the shorter pair which are in line with, or parallel to, the shorter axis of the shaft, and which are known as "end plates," or briefly "ends." This designation is now generally applied to the plates of both the vertical and inclined shafts, although it is probable that the name originated in connection with the timbering of the latter, in which the longer timbers of the set, the one supporting the hanging wall and that supporting the foot-wall of the working, naturally were called wall plates, and this significance of the term was finally extended to comprehend the similar longer plates of vertical shafts as well.
The above are parts belonging to the simple rectangular set of the single or one-compartment shaft, but the cross-sectional area of larger shafts is usually divided, for purposes of traffic, ventilation, and the accommodation of mining appliances, into two or more compartments separated from one another by divisional girts or "centers." In sinking through firm ground the bottom of the shaft is frequently excavated for a considerable distance ahead of, or below, the timber supports, in order that ample space may be afforded for the placing of the shaft sets, and to remove the timbers thereof from any possibility of being shattered or displaced by heavy blasts beneath. This allows the use of undivided full-length wall plates. In some ground, however, this is not permissible, and the material surrounding the shaft, through which it is being driven, may be of such texture as will make it imperative that the timbering shall closely follow, if indeed it does not crowd, the excavation of the working. Under such conditions the use of full-length wall plates is impossible, and therefore it is necessary to divide or "splice" such timbers that they may be brought into position. The girts act as distance pieces between the plates in order to preserve the width of the
shaft. At the points of division of the wall plates, at the splices, the girts are known as "splice centers/' while those used to separate the compartments, at such other points of the wall plates as are not spliced but solid, receive the simple designation of "centers."
Such being briefly a description of the different parts that are assembled together to form the rectangular shaft set, I will proceed to discuss the methods whereby the timbers are cut and framed in order that they may properly and truly join together and fit exactly at the joints. (See Fig. 99.) I will assume that they are of the desired length, and that they are square-sawed to the required cross-sectional area; but in the latter instance they are certain to vary slightly from the exact dimensions and often may be more or less twisted. One side or face, therefore, is selected — the most perfect and even one — if there should be marked imperfections, and this face is taken as a basis of operations.
It is necessary in the first place that this face shall be true, that is, without bend or twist as regards both its length and its breadth. Care in this particular is essential, as it determines the exactness with which the timber shall fit its companion pieces at their common joints in the assembled set; and therefore, upon a perfect plane throughout, or by means of it, depends in large measure the perfection of the set itself. Where extreme precision is required, the selected face is worked to straight-edges, sighting from one to another until at proper points the face has been worked to line with the assumed plane which is shown when the edges of the straight-edges are brought to coincide; bends and twists are removed locally wherever it may be necessary to frame a joint. In the process of framing many prefer to select for this face the one that will be the top or uppermost side of the timber when in its place in the set, and to take all lines, measurements and angles with regard to it; but for sufficient reasons I believe that the basis of all framing should preferably be that which will become the interior face of the piece when the parts shall have been assembled.
Upon this face a center or base line is marked from end to end, either by means of a straight-edge or the chalked line, and all measurements lengthwise along the timber are laid off with reference to this line, as also are those crosswise lines which
locate and outline the shapes of the joints to be framed upon the selected face, the relative positions thereof having been established by the measurements. This base line represents a line at which, should a second imaginary plane be passed lengthwise through the center of the timber at right angles to the
plane of the selected face, it would cut or coincide with the latter throughout its length; and this line of coincidence of the two planes we have fixed upon the face of the timber by marking, so that we may employ it as a basis for the laying out and framing of the joints. (Fig. 99, A and B.)
Backward from this face to required distances there are laid off tenons, mortises, gains and miters that go to make up the joints which will allow the different parts of the set to be brought together into one complete and perfectly connected whole. (Fig. 99 C.) By thus taking all measurements from the base line toward the top or bottom part of the timber, and by projecting the points and lines thus established backward from its selected inner face towards its outer face or back, all troubles due to twists or variations in the size or shape of the pieces going to make up a properly framed set may be overcome; and the joints thus framed will be in their correct relative positions, exact in size and shape, and they will join accurately with those of the other connecting parts of the set. It is needless to say that exactness in the fitting together of the joints cannot be expected unless all necessary precision has been employed in their framing.
The joints that must be framed in the construction of a set are: those at the corners of a shaft, which connect the wall plates and the end plates at their ends; those connecting the centers and splice centers with the wall plates at the division of the compartments; and, where it is required or used, the "boxing" of the ends of the posts into the frame in order to insure that they shall retain their proper positions. The framing of the wall plates and the methods of cutting their joints are shown in Fig. 99 D and E; that of the end plates, Fig. 99 F; of the centers, Fig. 99 G; and that for the splice center in Fig. 99 H.
The wall plates and end plates are joined together at right angles to each other by a combination of the tenon and miter, or "bevel," as the latter is usually designated. The thickness of the tenon is just half that of the plate, the measurements therefor being taken from the center or base line on which is formed one face of the tenons, their lengths being equal to the widths of the mating tenons of the joints. The wall plates invariably have their tenons at the bottom half of the pieces that they may support the end plates while the set is being placed in position in the shaft, the tenons of the end plates on the contrary being framed at the upper half of the ends in order that they may rest upon and be supported by those of the wall plates when the parts are assembled. This halving the timbers in framing tenon for the purpose of support removes just one-half of their cross-section and thereby weakens the pieces at such points proportionally.
This difficulty is overcome by the use of a half right-angled miter, of 45 deg., which is framed from the face of the timber backward usually to a depth of one inch; or, in other words, the piece is so beveled that this mitered face will coincide with and abut against a similar miter that is framed upon the companion piece, both being placed in the same relative position within the joint. By means of this construction of the corner joints of a shaft set it is brought about that the full cross-section of one plate engages the full cross-section of its companion plate at their common end, at which point the two pieces are at right angles to each other, and thereby it is assured that the full strength of one of the timbers supports and is supported by the full strength of the other.
In the case of the simple divisional girts or centers, instead of tenoning through the width of the wall plates at the joints, as do the ends and splice centers, they are connected therewith by a short V-shaped tenon that is mortised into a corresponding gain framed into the inner face of the wall plates at desired points, the tenon being narrower at the bottom than at the top in order that it may not fall or be forced out of its position. (Fig. 99 G.) The shoulders of this tenon should be constructed of a width sufficient to engage the face of the plate, whereby it may afford support to the full size of that timber. The simple center with some form of the V-tenon is employed for the purpose of dividing the cross-sectional area of a shaft into compartments, save only at points where the wall plates are spliced in order to shorten them so that they may be brought to position in confined quarters.
Whenever it becomes necessary to shorten the wall plates, the timbers are so cut that the splice will coincide with the lengthwise center line of one of the cross girts or centers that divide the shaft into one or more compartments. Generally, in the threecompartment shaft, which has been taken as a type for the reason that the framing of all of the different joints employed in shaft sets may be shown in simple detail, this cutting in two or splicing of the wall plates is made to center between the pump compartment and one of the hoisting compartments. The upper halves of the wall plates at such points are removed to a width that is somewhat less than the thickness of the splice-center there to be placed, in order that the shoulders extending beyond
the sides of the engaging tenon of the center may furnish support against side pressure to the full cross-sectional area, and therefore to the full strength of the plates themselves. (Fig. 99 E and H.)
The posts are not framed, although they should be cut with precision and their ends properly shaped so that they may come truly to position and that the effects resulting from any twist of the timber may be removed. Almost invariably throughout the metal mines of the western United States gains are framed into plates and centers of the set into which the ends of the posts are boxed, the shoulders of these gains being employed to support the posts in place against the inward thrust of outside pressure. (See Figs. 98 and 99.) On the other hand, the general practice throughout the eastern portion of the country, in metal and coal mining, is to do away with this boxing of the posts, to frame no gains for their reception, but to set them flush with the top and bottom faces of the set, and to depend upon the tightness with which the assembled parts are blocked and wedged into position for retaining them in their places.
In practice certain variations of these several joints are employed, oftentimes to advantage, but the above discussion is intended to describe the practical methods of framing the typical rectangular shaft set.
BY Louis S. GATES
BINGHAM, situated in Salt Lake county, Utah, about twentyfive miles south of Salt Lake City, has become one of the largest low-grade copper camps in the West. The ore occurs in large shoots varying from 50 to 200 ft. in width, from 100 to 300 ft. in length, and in some cases proving to be continuous in depth for over 600 ft. These chambers or shoots in most cases have a well-defined foot-wall of quart zite and a hanging of limestone, although some have been found imbedded entirely in the lime. There is no well-defined dip to these bodies as with the veins, and they are found varying in dip from the horizontal to the vertical.
The ore is heavy, running about 9 cu. ft. to the ton, and carries on an average 25 to 30 per cent, iron, 20 to 25 per cent, silica, 2 to 5 per cent, copper, $1 to S3 gold, and 1 to 4 oz. silver. In mining this ore great care is exercised, for it is not uniform in texture, changing in a very few feet from hard compact sulphide to a soft disintegrated silicious ore, which, unless caught up, will run and cause a cave. The large size of the orebodies, the variable texture of the heavy ore, and the added disadvantage of having a heavy hanging wall, have made it necessary for the square-set system to be universally used in mining the large shoots.
timber at the mine.
The sills are framed from 6xlO-in. timber cut 5 ft. long, dapped 1 in. on each end and cut in 4.5 in. in order to support onehalf of the posts on each end, as shown in Figs. 100 and 101. Occasionally, where long caps are used in order to leave out a
post in the sets, so that a curve may be made in the track, a long 10-ft. sill is used. Posts are cut from 9xlO-in. timber, 6 ft. 8 in. over all, and are framed on one end only, the base setting into the sills 1 in., and the top having a tenon 1 in. long and 6x7.5 in. The caps are framed on both ends, as shown in the sketches, from lOxlO-in. timber, and since they are framed down into the posts 1 in. it is evident that the sets are 5-ft. centers on the sill and 7 ft. 4-in. centers in elevation. The braces are made
from 6xlO-in. timber cut 4 ft. 4.5 in. and framed as shown in the sketch. For lagging, 2x8-in. lumber is used; any heavier than that is too strong, for it does not bend enough in event of great weight being exerted, nor give sufficient warning of impending danger.
The size and extent of the shoot having been determined, there are two methods of opening up the stopes dependent upon the character and dip of the orebody and the heaviness, of the hanging wall. The preferable method, illustrated by Fig. 102,
is used where the hanging wall is firm and the ore solid, allowing large chambers to be opened up" without danger of excessive pressure being exerted which would cave the stope. A definite level having been determined, the sills are laid for the first set at right angles to the general strike of the shoot. The sills are only 5 ft. long, for in most cases it is inexpedient to open enough ground ahead of the timber to lay longer sills. The sills in place and tamped down, a floor of single lagging is laid and the four posts erected. The caps are placed on the posts in the same relative position as the sills below, and braces are framed to fit the top of post and cap, thereby completing the square set; no braces or girders are used to keep the posts on the sills, but in their stead the floor lagging is laid from sill to sill, and a notch is cut in the lagging next to the post which acts as a foot brace and prevents any lateral motion of the post on the sill. A double floor of lagging is placed on the caps and braces and the set blocked securely, completing the first set of the stope.
This first set having been placed in one of the drifts, as near the center of the orebody as practicable, a row of lead sets is now started running longitudinally through the orebody; after this has been done, or the sets have been carried ahead four or five sets, another row of wing sets is started on one side of the lead sets, running parallel and adjoining them. The sill floor is opened up in this manner until four or five rows of sets have been carried along before st oping on the floors is begun. This method has been found more economical, for after once getting the lead sets through, there is an excellent opportunity to slice the ore off by simply starting another row of wing sets, and it affords more place for the machines to work than the second method.
The sill floor once opened up sufficiently, the first floor is opened up exactly as the sill, by driving a row of lead sets over the lead sets on the sill floor. Care is always taken to have the sill floor at least two and preferably four rows of sets wider than the first floor, thereby making it easy to keep the broken ore on the floors. The second and upper floors are then carried up, the object being to carry the lead sets right up to the middle of the body, thereby relieving the weight on the sill floor by resolving the downward pressure of the orebody into two components, a horizontal one resisted by caps and braces, and a vertical component resisted by posts. The stope then should resemble
a pyramid of blocks, with each lower layer extending one or two blocks beyond the next higher. After the lead sets have been carried up in this manner the floors are opened out by continual slicing until the walls are reached.
of a cave were the first method used, and especially where the nature and extent of the orebody is not known. In this case, as in the first, sills and caps are placed at right angles to the general strike of the shoot, but instead of starting at the center of the body the first set is placed as near the hanging wall as possible and the lead sets driven along the hanging. This row being driven ahead, a second row is started adjoining and parallel
to the first. After two rows have been driven, st oping is begun immediately by starting a row of sets directly over the second sill row and carried up by successive floors until the hanging wall is reached; when this is done, another row is driven on the sill floor and the sets carried up to the hanging wall. The stope is continued in this manner until worked out or it is advisable to cave it and start a new one.
The double advantage of this method is manifest. First, there is always a solid breast of ore on one side of the stope, which greatly relieves the pressure on the timbers; second, should the stope cave in unexpectedly, only the ore on the floors and in the chutes is lost, for a new stope can be opened up by driving a row of sets on the sill floor, right next to the caved stope, and then carrying them up to the hanging as before. On approaching
the hanging wall it is evident that it is not always possible to remove all the ore and catch the hanging wall up with full sets. In such cases short sets are used.
Formerly, when a short set was used, the post nearest the hanging was cut the desired length, and the post in the full set, into which the small set was framed, was cut the same length. The cap and braces were placed as in a regular set, then in order to complete the full set two small posts were framed into the small set. This scheme took a lot of time and weakened the posts of the full set.
In order to overcome this disadvantage, a method illustrated by Fig. 104 is used. A glance at this sketch shows that the post of the short set is placed in the usual position on the cap below, but instead of cutting the post in the full set in two, the tenon on the cap is cut off, allowing the cap to butt right up to the post. The cap is spiked to the post to hold it in position, and a piece of 2x8-in. lagging resting on the cap below is also spiked to the post and forms the support. To prevent lateral motion of the caps on the lagging, two pieces of 2x8-in. lagging are nailed together and spiked in position to be used as a brace on the end where the tenon is cut off, thereby holding the cap as securely as necessary. This method is simple and equally as efficient as the former, as it answers all the requirements.
When mining on the foot-wall, ground posts and butt caps or butt braces are used, depending on the steepness of the footwall. These methods are shown in Fig. 105. When the footwall is very steep, a piece of lOxlO-in. timber is framed on one end as a cap or brace, as the case may be, to fit into the full set, the top is cut 1 in. deep and 9x10 in. to fit the posts, and the sides 1.25 in. deep by 6x10 in., or 1.25x9x10 in. to fit the brace or cap, and cut long enough to fit the hitch which is cut into the footwall, deep enough to make the butt cap or brace secure.
In cases where the foot-wall slopes off so much that it is impossible to place the butt cap, so that it is resting on solid ground at the point where the post is placed on it, the butt cap is framed as before, except that the bottom is cut 1 in. deep by 9x10 in. to hold a post which affords the necessary support under the post which is placed above on the cap. Frequently spreaders of lagging are placed, extending from the base of the ground post to the post of the full set, to hold it in position.
When a post shows signs of weakness, instead of putting in a false set to strengthen it, angle braces are used. For example, a post on the sill floor shows signs of weakness; the angle braces are framed to fit between the top of the post directly over the weakened one and its cap, -and extend diagonally downward to fit between the cap and the foot of the posts on each side. In
not decreasing the head room.
Economy is evident in all workings. For often, in shooting, a cap or brace is shot down on the post, injuring the tenon; instead of a new piece of timber being put in, the old one is knocked back in position, and a piece of lagging spiked to the side of each post upon which the injured member rests, reaching to the sill, or, if on the floors, a cap, thus forming a support on each end
injured timber in place.
In blocking the sets down, care is used to see that the timbermen always put the blocking as nearly as possible over the posts and never near the center of the brace or cap, on account of the leverage exerted on the timber, should the set take weight. When shooting, especially in hard ground, the timbers are faced with old lagging, and double floors are used to prevent large boulders breaking through the floors.
When much waste is broken in stoping, it is not run over the dump, but, instead, certain sets are lagged up to the hanging wall and the waste thrown in to be used as filling, making columns which greatly aid in holding back the ground. When a stope has been worked out, floors, pipes, ladders and everything movable are taken out and 1-in. holes bored in nearly all of the posts in the sill floor; powder is inserted and the whole round is shot by a battery, caving the stope.
BY CLAUDE T. RICE
AT present square-set timbering is mainly used in mining the orebodies at Bingham Canon, Utah. As the orebodies are mainly replacement deposits in the limestone along mineralizing fissures, the walls of the orebodies are generally strong except where the limestone has been shattered by faulting. Because of this strength of wall, complete filling of the stopes with waste, such as is the practice at Butte, Mont., where in some of the square-set stopes the filling or "gob" is kept within two floors of the roof of the stope, is not required.
MINING METHODS
Consequently the orebodies of Bingham are mined without much waste filling, thus resembling the open square-set stopes of some of the Leadville mines where the ores also occur in limestone. Whenever a stope shows signs of a "taking weight" a few square sets are lagged and waste is dumped into this pen, forming a waste-filled bulkhead which helps materially to steady the stope. These "pen" bulkheads work so satisfactorily that I failed to see any wooden bulkheads such as are used in some of the Boston & Montana mines at Butte.
The chutes are simply plank-lagged square sets with occasional offsets to break the fall. Owing to the softness of these sulphide ores there is no excessive amount of cutting of the lining of the chutes, and consequently neither "bricked" chutes nor the open staggered chutes which characterized the open square-set stopes of the Homestake mine, at Lead, S. D., are necessary. Two-inch planks are used for floors in the stopes. Owing to the strength of the ore and the little tendency it has to scale off, the roof sets of the stope generally do not have to
However, the mine managers at Bingham have not been quite satisfied with these advantages, but have designed, in order to save timber, a specially framed square set, which, at least as
far as my experience indicates, is peculiar to these mines. This system was first used at the Highland Boy mine of the Utah Consolidated and has later been adopted at the near-by Boston Consolidated mine. It has proved so satisfactory that the same framing of square sets is used at the Cactus mine at Newhouse, Utah, which like the Boston Consolidated is under the control of Samuel Newhouse.
butting against those of the posts below. This framing is still retained in the few square sets used at present on the Comstock. Whether the downward pressure there is greater than the side pressure, as the framing would indicate, I do not know, but I could not help noticing this feature of the framing of the original square sets, which to me at least is unique; for although I have worked in many mines, and visited many more, in which squareset timbering is used, I have not seen elsewhere this feature of butting the posts against each other.
PECULIARITIES OF THE BINGHAM PRACTICE
At Bingham Canon the sets are designed to offer the greatest resistance to side pressure and so the horns of the caps are caused to butt against each other, the cap being 10x10 in. square. In this butting of the caps there is nothing unusual, but in the posts we have the unique feature of a piece rectangular in section instead of square, the post being 10 in. wide in the direction of the girts and 9 in. wide cap-ways, thus saving an inch in the cross-section of the posts. Moreover, the posts have a bottom and a top end, for they are "bald" at the bottom and have only a 1-in. horn on top. In consequence of this framing of the post, the top mortise made up by the assembling of the caps and girts differs from the bottom mortise, and so there is a top side and bottom side to the caps and girts. This at first confuses the green timber man used to caps without a bottom or top side, but of course this is no valid objection to this square set. Naturally, it is necessary to have a tenon on the top end of the post on which to rest the caps and girts. As the botlbom of the post rests on the caps and girts it does not need to be framed, but it seems to me that it would be just as well to have the top and the bottom ends of the posts similarly framed with horns, for then there would be no such complicated arrangement of framing as the present design demands in the caps and girts. True, that would cause an extra pass of the post in the framer, but it would avoid the special framing of a cap only on the top side of the girt. If the similar framing of both ends of the post were adopted the girt would be a plain 6xlO-in. timber resembling the girt used by F. A. Heinze at the Cora-Rock Island mine at Butte, Mont., where (if my memory be correct) the girts are plain,
CRITICISM OF THE SYSTEM
This making of the girt only 6x10 in. in cross-section appears to be a step in the right direction; for the purpose of the girt or tie, or, as it is better called in some camps, the brace, is mainly to resist the side movement of the caps and is not to resist any great inward pressure in the stope as is the function of the cap. Consequently the girt does not have to be as strong as the cap. In my opinion it is a waste of timber to make the girts equal in cross-section to the caps.
Another feature that strikes me as worthy of consideration is the fact that although the vertical distance in the clear between the caps and the posts is 6 ft. 5 in., the distance in the clear capways and girt-ways in the sets is only a little over 4 ft. It might be possible to increase this distance, and effect still more economy in the timbering without endangering the stope, but this last matter of course is a point for men well acquainted with the ground to decide, and undoubtedly it has been given much thought by the Highland Boy management, which is noted for its high efficiency. I mentioned the point only because of the striking difference in these dimensions, which the managements of these mines have thought necessary. The only drawback to the girt being as narrow as 6 in. is the ease with which a floor can be torn up by a heavy blast in the stope, unless the floor is tightly wedged in place, for it has only a 3-in. hold when laid capways. But this, of course, is a very small drawback.
The arrangement of the sets is shown in Fig. 106.
Owing to the fact that the dimensions were scaled to the timbers themselves and not taken from a drawing, there may be some slight mistakes (even J in.) in some of the dimensions, but the dimensions of the sets are in the main correct.
BY W. R. CRANE
MUCH timbering is done in the copper mines of northern Michigan, although in many of them the use of timber is confined almost exclusively to the shafts, pillars being depended upon for support of the hanging wall in the stopes. The problem of support of workings several thousand feet distant, vertically, below the surface is becoming more difficult of solution with the lapse of time, owing to the rapidly increasing area of workings only partially supported, and to a less extent to the collapse of the supports, pillars, or timber in the upper levels. The enormous loads thrown upon the hanging walls of large open stopes, which are supported by pillars or timbers of only a very small proportionate part of the total area exposed, must ultimately cause their disintegration, which, when it occurs, may start a movement that may be very slight, yet the results would be difficult to conjecture.
Where portions of the vein filling are left for support of hanging wall, the idea is to remove ultimately as much of it as possible before it collapses and before any fall of roof would interfere with the operations carried on below. No systematic attempt has been made to rob pillars, except in the filling system, in which case those left standing and finally removed are the floor or chain pillars. That none too large pillars are left for the support of the hanging wall is evidenced by the rapid breaking up of such unmined portions, and that, too, in the course of but a few years.
Timbering may be used as an auxiliary to pillars, and alone, even, as temporary support, and is in fact employed extensively both ways. Probably mine support by timbering is carried on most extensively and systematically in the Calumet and Hecla and the Tamarack mines, which are among the largest and deepest in the district. It would seem, after the disturbances which have
recently occurred in several of the mines of this district, that ultimately filling of the stopes with waste must be the solution of the problem of support. No attempt is made in this connection to give details of all of the forms of timbering employed, but rather to make note of only a few typical forms which have come under our observation.
TIMBERING IN SHAFTS
The method of sinking practically all of the shafts through the surface materials, which are usually sands and gravels, is by drop shafts, consisting of frames and studdles forming sets, to which additions can be made indefinitely. These sets, when securely bound together by bolts and inclosed in a sheathing of lagging, maintain the shape and alinement of the shaft and keep out any quicksand that might enter otherwise. Below the point where the surface materials terminate, and where the shafts enter solid rock, often no timbering is necessary, for a time at least, the excavation being self-supporting.
The arrangement of the timbering used in self-supporting excavations is shown in Fig. 107. The long sleepers, running transversely with the shaft, are set in hitches cut in the sides of the shaft, and are carefully alined with the finished portion. Timbering in this manner is done in reverse order to shaft sinking, i.e., is carried on from below upward, the object being to facilitate matters. Timbers are placed FIG. 107. — SHAFT TIMBERup to the rock pentice, which is left ING' Plan and section' as a protection to the operations in the shaft below, and when it is removed, only a few pieces of timber remain to be put in place to complete the support of the tracks, ladders, etc. The
alinement of sleepers placed in this manner is rendered considerably more difficult than if carried downward continuously from the finished shaft above, the work of alinement having to be carried on through the small sinking shaft and to a point 100 ft. below the end of the working portion.
20. Props
The sleepers having been placed and securely wedged in position, the ties are next put in position, being set alternately with ends overlapping. The sleepers are 12x12 in. by 17 ft. 8 in. and are spaced 8 ft. apart, center to center. There are six 7x8-in. or 7xlO-in. ties placed between two adjacent sleepers. A partition 4 ft. high separates the hoisting compartments from the manway, which is 4 ft. wide. Posts (10x10 in.), set between the foot- and hanging walls, support the 2-in. planking of the partition, which serves as a protection against falling rock
On the up-shaft side of the sleepers are fastened planks, which extend from the top of the sleepers to the bottom of the shaft excavation, thus dividing that portion of the shaft flush with the tops of the sleepers and ties into sections or pockets, as it were, by the plank dams. These sections are filled with fine mine dirt, the placing of the dirt being accomplished by a small skip of about two tons capacity, which is provided with a small gate at the lower part of the rear end. A load of dirt is hoisted to the point in the shaft desired and the gate is opened by simply unlatching it, when the dirt runs out and is spread largely by gravity.
CONCRETE LINING
When the shaft excavation is not self-supporting, the framing employed in the quicksand and other surface materials, or similar forms, is resorted to, usually, however, without lagging. Aside from timbering, concrete linings are occasionally employed, which reach from the surface to bed rock, with which connection is made, thus effectively shutting off the water that is often encountered in large quantities in the loose surface accumulations of gravel and sand. Concrete is also used in the rock excavation of shafts, where it serves as support for the tracks, being built either in transverse ties or longitudinal stringers for the rails to rest upon and be fastened to by long bolts passing through plates in the body of the structure.
TIMBERING IN DRIFTS AND STOPES
In the workings, i.e., levels and stopes, timbering takes the form of stulls and square sets, and all imaginable combinations of the two. In the deeper levels of the Tamarack mines, stulls, both in the form of individual members and in groups of three or four, set close together (commonly known as batteries of stulls), are extensively employed. The batteries are spaced from 8 to 10 ft. apart and may be used in combination with individual stulls. Stull timbers range in size from 1 to 4 ft. in diameter. They are carefully measured and cut on the surface, and then carried below and set normal to the lode, being wedged fast.
The arrangement of timbers employed in levels, which serves as a basis for the building of square sets in stopes, is shown in Fig. 108. Further, square setting may be stopped at any time and the face of the timbering covered with lagging as shown. One form of square-set joining is shown in Fig. 109. The forms of the individual members are shown in three projections each, from A to G, while in H is shown a combination of A, B and C (a joint for a standard set) , and in I are grouped F and G and a form of C. The arrangement of timbers shown in H is a plan of the joint at A, Fig. 108, while in I is shown a plan of the joint B. The blind double ender D is used with B and C in joint at C. In H and I the dotted lines represent the members above and below the plane of the plan given, always similar, but not necessarily vertical.
Timber caps, or wall pieces, usually rough round logs, are also employed, being supported by pack walls built along the lines of the levels. A lagging of rough poles is placed on the caps and waste rock piled on these in turn. Levels are thus formed and maintained in the Baltic and Trimountain mines, where filling methods are employed; often as much as 30 to 50 ft. of waste filling may rest upon the caps.
Timber as a means of support for the mines has a wide range of usefulness in this district and will always be an important factor in mining regardless of the methods employed.
BY J. H. BATCHELLER
THE timber principally used is fir and tamarack. Bull pine, in large sticks, seems to mildew and rot too rapidly for good service, though in the form of planks, spiling, track ties and wedges it does well enough. Fir and tamarack seem to resist decay equally well, even in old workings. There is, however, one limitation to the use of tamarack : it bears end pressure well, but is too brittle to give good service under any side or transverse stress. Because of this failing, tamarack is rarely sawed into square timbers, such as caps, ties, etc., but it is cut into posts, stulls, helpers, angle braces, sprags, poles, chute cribbing and chute lining, Fir not only serves for all of the above, but is also cut into sills, caps, ties, and plates.
In a general way, there are four different principles recognized as making for economy in timbering: first, the utilization of all the products from cutting the raw material; second, the use of simple, framed joints; third, the adapting of the size and number of timbers used to the duty required; and, fourth, the use of a uniform system of timbering throughout the mines.
The saving under the first head is accomplished in the following way: The trimmings made in squaring timbers are cut into 5-ft. lengths called "slabs," which are used in covering square sets under bulkheads, and in cribbing waste-fillings. The vends of large round timbers — too short for squaring into caps, ties, or collar braces — down to about 2.5 ft. in length, are framed with a top tenon 4x4x7 in. long (Fig. 110) on one end and left flat on the other. They are used for foot-wall stope-set posts (Figs. 115 and 116). Ends shorter than 2.5 ft. are cut into wedges.
The planks — 2, 3 and 4 in. thick — are purchased ready cut. The 2-in. planks are used in chutes, flooring, and as spreader boards in tunnel sets. Three-inch planks, 5 ft. long, are employed for flooring and short chutes. Three- and 4-in. planks 8 and 10 ft. long are used in temporary slide chutes in newly started stopes, before they are cut out high enough for permanent cribbed chutes. The lagging is split cedar, 5 ft. long, and used in bulkheads (Figs. 113, 114 and 115), waste cribs,
and as temporary sprags and blocks, around newly erected square sets. The economy of material is almost perfect. A given stick of round timber will yield but little to go into the refuse pile, as the series of useful articles runs from quadruple ties 19 ft. 8 in. by 8 ft. 10 in., down to short chute cribbing 3 ft. 10 in. long by 4 in. diameter.
Under the second principle governing economy, a system of framing has been worked out to conform with the idea, first, that the less the end of a timber is cut to make a joint, the stronger the joint; and, second, that all joints are a source of weakness.
Simple joints not only economize material, but cost less in framing and in labor of erecting. Under the first, note the framed ends of the square-set timbers (Figs. 110, 111, 112 and 115), of the tunnelset timbers (Figs. 118 and 119), and of the shaft set timbers (Figs. 120 and 121).
In the framing of square sets there are several advantages in having the top tenon of the post longer than the bottom one. This arrangement leaves only a shallow hole, the bottom of which is easily reached with the fingers, to be cleaned out of the joint to make ready for stoping a new post. At the top end, the longer tenon not only gives a better hold on the newly placed cap and tie, but also gives a better chance to block the post itself to the
ground. The straight tunnel-set timbers have no framing whatever save only the shallow notch cut on the inside of the posts, at the top. This serves merely as a shoulder on which the spreader" board can rest. In the battered sets, the under side of the cap is notched at the ends, to leave a portion in the center for a spreader to the posts; then the ends are beveled merely enough to give the square ends of the posts a firm seat. In both styles of sets, the full cross-section strength of the posts is retained. The loss of strength to the cap of a battered set, from notching the under side at the ends, is partially made up by its having less distance to span than the straight-set cap. The inclinedshaft sets are of far greater strength, under this system of framing, than under the vertical-shaft system, where the plates are
joined with half-splice tenons. This method is possible in inclined shafts, where the end plates carry but little side pressure, and it gives full cross-section strength to the timbers holding the wall plates.
In recognizing that all joints are a source of weakness, note the use of double, triple, and quadruple ties (Figs. 116 and 117). At first thought, it might seem that this point does not concern the matter of "simple framed joints." However, as there is a
limit to the length and size of timbers that can be used, there will have to be many joints. By using long ties, the joints where they are supported by helpers are the simplest and strongest for
the work, as they are merely butt-end bearings. Owing to the limited size of the drawing, no full-length quadruple tie is shown in Figs. 116 and 117. They are, however, extensively used on
the sill and second floors of stopes. Above the second sets in a stope, they become impracticable because their length makes them too difficult to handle. Triple ties can be used in many places for three or four sets up, but at last they, too, are discarded when it becomes too difficult to get them into place. Double ties can be turned anywhere, and are used wherever possible.
The third principle — that of adapting the size and the number of timbers to be used, to the duty required — is illustrated in every feature of the methods of timbering, and constitutes one of the most important points of economy. The term "duty" must be understood to mean not only the amount of immediate weight a timber must hold, but also the probable
future weight and length of time it will be desired to hold. Note (Figs. 116 and 117) how the light stope sets are used like stagings to work on, while the weight of the ground is carried principally by the waste filling. Where the ground gets too heavy for the stope sets alone, the small, inexpensive, unframed helpers and angle braces are put in alongside of the square-set posts to give local relief, sufficient to serve until filling is completed around these places. On the top floors, wherever suspicious pieces of ground threaten to fall in large masses, big stulls, sometimes footed against the timbers, and sometimes on the filling, are put in temporarily until the ground is taken down and square sets erected.
are placed under the long ties, in the positions where framed posts would come, if the sets were of short length. Side helpers are put next to framed posts to hold up the failing ends of caps and ties. Angle braces are put in to prevent the sets from "riding" (or leaning). The tops and bottoms of the posts, against which they are set, must have either tenons or sprags to hold against the side thrust. This merely means that angle braces do no good if placed against the flat-bottomed helpers unless the latter are strongly held from being pushed out of position. Sometimes two angle braces are put in to lean against
each other, like a triangular truss, to take the place of a post, or center helper (Figs. 116 and 122). In this case the object is to take all possible weight from above the center of a drift and transfer it to the sides. All angle braces, stulls and helpers are sawed to measure at the time of erection, and are cut to drive home tight. They are always put in butt-end up, as it has been found they do not split lengthwise as readily that way as with the small end up.
The use of long ties — when the ground does not break too short to be opened up sufficiently — offers a number of advantages. Not only does it save one, two, or three framed posts,
respectively — as the ties are double, triple, or quadruple length — but also just twice the number of caps as posts (that is, two caps for each post). Further, there is a saving in size of the timbers put in the place of the posts. The strength of a 9-in. center helper is greater than the transverse strength of the 8xlO-in. tie on top, for the latter will almost invariably break first, or mash down, or turn over, before the helper fails. This is a saving of two inches in the diameter of the timber, for framed posts, on an average, are never less than 11 in. in diameter when
round, and they are, of course, cut from still larger timber when squared to 10x10 in. In place of the two caps saved where each center helper goes, small sprags or girts are put in and driven tight.
Besides the matter of economy, the long ties have the advantage of greater strength. Where a tie extends over the top of a helper, all the top fibers of the timber lend their tensile strength to the others in the span, which is not the case where a joint occurs. The use of long ties has also a marked tendency to
stiffen the stope timbers, and makes it easier to hold them all in good condition till filling is completed. This advantage of stiffening the stope timbers amounts to a great deal where cribbed chutes come up every four sets, from one end of the stope to the other, parallel with the pitch of the ore shoot. As ties are always placed across the stope — from foot to hanging — the chutes come up between them. The slope of a chute often necessitates the removal of a cap, thus greatly weakening the joints of the two sets on either side. However, where long ties are used on either side, at the point where a chute crosses a set, there are no caps in the way, and the girts are moved merely enough to give clearance.
The system of using double drift sets (Figs. 116, 117 and 124), at points where long life and power to bear great weight are desired, is another important feature in the timbering practice. These sets are usually put up only where a drift or a station is to be kept open for a long while under a filled stope. As the outside posts and cap in no way affect the inner set, the single set undergoes no break or change where it joins or leaves the double portion.
The use of a uniform system of timbering permits of a saving not only in material, but also in labor. All stope, drift, adit, and shaft sets, and stulls holding filling, are put in 5 ft. apart — center to center. Flooring planks, slabs, lagging and poles are cut a bare inch short of 5 ft. long; so that they can be used equally
well in all parts of the mine. Another, though minor point, is that the caps and ties are of the same cross-section; therefore, if required, a cap can always be framed from a tie. The uniformity of system lessens the amount of dimension stuff necessary to hold in stock, and saves many minor delays to the timber gangs underground.
The foregoing remarks cover some of the details of the methods, but are concerned mostly with their economic side. There is, however, an equal or larger number of points that are of great importance to the efficiency of all timbering. Attention can best
on the accompanying figures.
On comparing Figs. 110-114, 116, 117 and 123 with Figs. 115 and 122, it will be noticed that the latter show round stope-set posts, while in the former they are shown square. They were drawn square purely as a matter of convenience, and, furthermore, though not especially common, posts 10x10 in. square occasionally come in from the sawmill. The average size is 11 in. butt diameter. This does not occasion any loss in strength to the square sets. The cross-section area of the lOxlO-in. stick is only 100 sq. in., as against 95 sq. in. cross-section of the 11-in. round post. Examination of the details of the bearing
surfaces of caps and ties shows that on a lOxlO-in. post each cap will cover 16 sq. in., and each tie 24 sq. in. The total area of cross-section can be accounted for as follows:
For all practical purposes the 95-sq. in. cross-section of the 11-in. post gives as good service as the 96-sq. in. useful bearing surface of the lOxlO-in. post. There is yet another advantage, besides the economical one already pointed out. Of the two sizes, the round post, though smaller, will invariably be the stronger, because it possesses all the strength of the original outside fibers of the timber, while the squared post is weakened by having them cut.
indicates clearly the reason why bulkheads should always be started from the ties rather than across the caps. In the details of a bulkhead (Figs. 113, 114 and 115), observe that the planks from which it starts are laid across the ties. In erecting, the lagging is cribbed up till there is not room for more, then blocks are put in and wedged as tight as it is possible to strike them. Owing to their inconvenient position, it is often impossible to jamb the whole bulkhead tight by means of the top wedges alone. To accomplish this, wedges are driven in at the four corners below, over the planks, and the whole structure is keyed up tight. This is of prime importance, for the bulkhead is needed, not only to hold the ground from slacking away, but in steadying the square sets from swinging when shots are fired near by. It is also important that all newly erected timbers should be tightly blocked and spragged from the ends to the ground; likewise all flat-bottomed posts and helpers, wherever they may be in danger of being shot out. It is only by holding all timbers rigid that stope sets can be held from "riding." When once "riding" starts, it is not only difficult but expensive to stop.
The foundation planks of a bulkhead are usually cut with a saw, 5 in. back from each end, 5 in. deep, on the sides that overlie the caps; so that when a new post is to be erected on top of one of those by the bulkhead, one blow from an ax will knock off the 5x5-in. block, and make room, without chopping the grit-covered planks, for the foot of the post. As the cedar lagging is softer than the wood in the planks and timbers, the condition of a bulkhead always gives first warning, by its state of compression, of the square sets taking any excessive weight. Though not shown in the drawing, slabs are frequently used across the ties, between the foundation planks, to serve as a covering to the sets. These slabs never carry any of the weight, but merely keep small rocks from sloughing off on the men below. Bulkhead material can be used over and over, till too badly crushed and broken to bear weight. After that it — and all other useless truck — is thrown into the waste fillings. Where long ties are used, bulkheads are built in exactly the same manner, in units; only two, three or four are erected to correspond with the length of the tie.
the timbers around and above the tunnel sets were well secured by filling, the direction of the sets was changed from having the ties point perpendicularly to the direction of the adit and the strike of the vein till the ties lay parallel with the axis of the ore shoot. The pitch of the orebodies rarely coincides with the dip of the foot-wall. Most commonly it lies at some oblique angle. Where the erection of angle sets begins, it is sometimes necessary to use horizontal braces or sprags, from the straight (the original) sets, diagonally or cornerwise through the angle sets over to the foot-wall. This diagonal bracing ceases naturally when the original straight sets are worked out against the hanging wall of the stppe; and the connection between the two classes of sets is held by filling.
The particular advantage of turning the sets lies in the possibility of keeping the chutes always along in the stope, and those that start in the stope at the sill floor can be carried clear up to the level above. If the sets were continued as begun, perpendicular to the strike, the chutes at one end of the sill floor would soon run into barren ground above the ore shoot, while at the other end the stope would soon reach diagonally up and beyond the last chute started in ore on the level. From this level, on this side, it would then become necessary to run raises through barren ground in order to get chutes up to the stope for ore. There would be no way to avoid the condition, for the ore chutes could not well be made small enough to turn diagonally up through the stope sets without their being too small for any service.
Two sizes are used, known as foot-wall and hanging wall chutes. The former are 4 ft. high by 3 ft. wide in the clear inside, and the latter 3x3 ft. inside. The chute cribbing is round and varies from 4 to 10 in. in diameter. The ends are sawed so as to leave a flat tenon 5 in. long by 3, 4, or 5 in. thick, according to the diameter of the stick. (Fig. 119.) With a 5-in. tenon on each end, and the inside clearance of 3 and 4 ft. respectively, the cribbing measure is 3 ft. 10 in. and 4 ft. 10 in. The inside clearance between stope posts and ties is practically 4 ft. 2 in., so there is ample room in which to build chutes and make the turn necessary where the angle sets start away from the straight sets. Manways are made in exactly the same way as the foot-wall chutes, 4x3 ft., but are always built entirely
handled from one gangway.
Sometimes stopes are started from the sill floor in a slightly different manner from that indicated in Figs. 116 and 117. Sillfloor posts 8.5 ft. in the clear, with flat bottom and a 4x4 x7-in. top tenon, are used. On top of these regular stope-ties and caps are placed. Pillars of cribbed filling are put in to hold the stope above, and a heavy covering floor is laid over the gangways and stations left open between the pillars. On top of the pillars and heavy flooring are laid the stope sills proper, for the regular 7-ft. square-set posts, entirely independent of the sill floor below. When this procedure is followed, the single tunnel set is usually enough, and the cap is braced by means of an extension or heavy sprag put in against the end from a hitch cut in the foot-wall.
However a stope may be timbered above, it is always started on good sills. These are covered with stout poles to hold the filling against the time when the ore in the floor will be taken out by stoping from a level below.
In closing the comments directed solely to stope timbering, there are some interesting points worthy of comparison between the 7-ft. clear sets used in the Bunker Hill and Sullivan Company's mines, and the 6-ft. clear sets used by some other mining companies. It must be remembered that in each case the thickness of the flooring planks must be deducted from these measurements, which leaves these sets with 6 ft. 9 in. walking room, as against 5 ft. 9 in. in the clear for the others. The longer posts give greater efficiency to the working powers of the men in the stope. For example, only an exceptionally tall man would be unable to walk erect, with timbers or steel on his shoulders, in a 6 ft. 9-in. clearance. Furthermore, angle braces frequently have to be put in where a passageway is being used to reach a chute. A 7-in. angle brace put in across a 7-ft. square set, still leaves room for a man to run the average sized iron wheelbarrow under it; while the same timber between 6-ft. posts would stop the way.
As a matter of economy, the longer posts are desirable. It would take only 41 posts 7 ft. 10 in. long to gain a vertical hight of 321 ft. 2 in. against 47 posts 6 ft. 10 in. for the same distance. This means a total saving of 6 long posts, or of one 7 ft. 10-in.
post in every 53 ft. 8 in. In a stope of given hight, there is not, of course, any saving in the number of feet of timber put in vertically, but the use of the longer posts saves the cost of one complete floor for the whole stope — caps, ties, general material, and labor — in every 53 ft. 8 in. vertical.
Figure 118 needs but little comment. The battered tunnel sets are the cheaper, both in material and in the amount of ground necessary to be broken out. The posts are frequently given more batter, where the ground is softer and has more side weight. The drawing represents the minimum amount.
Since they are not put up on sills, battered sets are not used in places where the floor will be worked out from below. The straight tunnel sets have top and bottom spreader boards spiked to the caps and sills. There are several sizes used in the mines, varying slightly in the hight of the posts as well as in the dimensions of the timbers. The choice of a given size is governed by the place where the sets are wanted, and the duty they must fulfil. Double tunnel sets are made by placing an extra large straight set outside of the ordinary single set. Figures 116, 117, and 118 show the double sets, and 7-ft. square sets erected side by side from the same floor. The principal point is that tunnel sets of any style should always be made, as nearly as possible, free and independent of the stone sets; so that any settling or swinging of the latter will not affect the gangway.
The inclined shaft sets shown in Figs. 120 and 121 have already received comment. Where the inclination is not too great, the V tenon and mortise joint can be omitted, and then a two-compartment shaft set becomes nothing more than a two-compartment tunnel set, on a slope instead of horizontal. This latter method of timbering is successfully used in one 45-degree shaft. The limits governing its general use would be the amount of side pressure the end plates would have to carry, and also the increasing difficulty of erecting as the slope becomes greater; since there would be no V tenons and mortises to hold the end plates from dropping out while the set was being blocked and wedged.
Figures 125 and 126 show the general arrangement of the timbers at shaft stations on levels. The dotted lines in Fig. 126 show the chutes cut in the rock, just outside the shaft covering, connecting the places where the cars are dumped at the station with the chutes in the bottom compartments of the shaft.
Figures 127 and 131 show some points in detail that are quite common in use. Figure 127 shows how segments should be framed to support a long station cap, when the load is uniformly distributed along the cap. The plane of the joints should be so cut as to bisect the angle formed by the intersection of the two
adjacent segments. This practically gives them the same shape and carrying strength as an arch. Figure 130 shows at a glance how the framing should not be done. The center segment would not carry any load, but would act merely as a spreader. Furthermore, the vertical side segments would carry but little weight, while the sloping side segments would thrust almost entirely out-
ward. Figure 129 shows the manner of holding up slope timbers so that a post can be cut off. There is no opportunity for choice as to how the top ends of the sloping segments should be framed, but at the bottom ends a method is shown which is better than in Fig. 130, though not as good as in Fig. 127. The only advantage of this method in Fig. 129 is that the vertical side segments do not have to be as large timbers as in the others. For the sake of simplicity in the drawings, it is not indicated that the posts of sets must be held against the side thrust of the segments by fillings or sprags.
Figure 131 shows the details of the framing of two angle braces put in from one floor up to the tie or cap of the set above, to hold a load concentrated at one point. It is similar to the method shown in Figs. 116 and 122, save that in this case the timber supported runs across the direction of the angle braces. In these cases no sprags or cribbed fillings are necessary to hold the side posts, for the thrust is resisted by the bottom tenons. Figure 128 shows how a tunnel may be widened, say to make room for a double track, without discarding all the timbers in place. This method, however, cannot be used unless the con-
dition of the ground is favorable, for there is the weakness of two joints on that side, instead of one. In good ground, the short side post may even be safely dispensed with, and a hitch can be cut in the foot-wall for the bottom end of the sloping segment.
Slight mention has been made of stull timbering. It is a large and important part of the work, though there are but few details that seem to lend themselves to description. Nevertheless, it calls for as much, if not greater, skill and judgment on
the part of the timberman to point his stulls and balance the ground to the best advantage, as in any other work. A few features are shown in Figs. 132 and 133. It is always preferable to build the chutes on the foot, not only to get all the steepness of grade possible, but also because it is more convenient for loading cars when the level is run on a bench cut in the foot-wall. It is desirable to run a level thus, in order that it may be left intact when the next stope from below comes through the ore left in the bottom. Sometimes, when the stope is not too high and
the slope is sufficiently steep, no cribbed chute is built at all. In this case the broken rock runs down over the foot-wall in a passage kept open between two rows of stulls, lagged and filled on the outside. Figure 133 shows a cribbed manway built up into the stope alongside of the ore chute.
Before closing these notes on timbering in the Bunker Hill and Sullivan mines, some figures of costs in regard to square-set timbering will be of interest. Exclusive of the initial cost of material and freight, the total cost of square -set posts, caps, and ties, delivered at the mouth of the mine, is as follows: posts, 12. 5c.; caps and ties, lOc. each. These figures include not only
The center dimensions of a standard set are 7ft. 10 in. by 5x5 ft.; giving a contents of 195.75 cu. ft. Assume, for an example, that a set is being put up in ore carrying 20 per cent, galena (about 17.3 per cent, lead) with a heavy quartzite gangue. The specific gravities would be, approximately, galena 7.5, gangue 3.3; and under these conditions it would take about 8.61 cu. ft. of ore in place (unbroken) to make a ton. This would give 22.74 tons for the contents of one square set. There are parts of 12 timbers in each set — four posts, four caps and four ties (see Fig. 123), but only one-fourth of each of these can be charged to a single set. This would be equivalent to one post, one cap and one tie, at a total cost, for outside handling and framing, of 32. 5c. per set, or 1.429c. per ton.
panying figures are made from timbers actually in place.
In concluding, I wish to express my thanks to Mr. Stanley A. Easton, manager, and to Mr. T. H. Simmonds, superintendent, of the Bunker Hill and Sullivan Mining and Concentrating Company for the assistance they gave me in gathering information.
BY T. J. GREENWAY
IN working the Chillagoe mines, in northern Queensland, the conditions are such as render necessary the adoption of some method of square-set timbering which will permit of the use of the stunted and twisted local timber without the aid of a sawmill. After experimenting with various methods of cutting and framing round timber, I devised and adopted the method de-
years.
The square sets are made up of the usual members, namely, posts, caps and stretchers. The shape of the posts is shown in Figs. 135 and 137, and the shape of the caps and stretchers, which are alike in every respect, is shown in Fig. 138. All are
cut from rough-hewn logs which are delivered at the various mines by timber-getters in accordance with a specification requiring that the logs shall have a clear minimum length of 6 ft. 6 in., and a minimum diameter of 10 in. The heavier logs are selected for making the posts, and the lighter ones are used for making the caps and stretchers.
10 in. least diameter.
The various set members are cut to the required shapes and dimensions by a simple method of sawing and adzing the logs, accurate measuring, centering, etc., being attained by using the miter box and the angle and square templates shown in Figs. 134, 136, and 139.
A post is made by fixing a selected log in the miter box (by means of wooden wedges) with one rough end projecting out of the squared end of the miter box. This rough end is then cut off flush with the end of the miter box, and the other rough end is cut off to a length determined by the transverse gage cut in the miter box. The post, after having been thus cut square and true to the required length, is taken out of the miter box and firmly fixed in a suitable saw and frame, and the ends are then shaped into square tenons by sawing and adzing them to dimensions which are gaged and squared by means of the square template with its accompanying spirit level.
A cap or stretcher is made by fixing a log in the miter box, and cutting it to the length and shape determined by the miter cuts. It is then removed to a sawing frame, and the beveled ends are shaped into miter tenons by sawing and adzing them to the required dimensions, which are determined by means of the angle template.
underground is clearly shown in Fig. 140.
With this method of cutting and framing, the use of rough log timber for square-set timbering presents no difficulties. As need scarcely be said, such timber is, weight by weight, much cheaper and stronger than sawed timber, and it can be used in remote districts where sawed timber is practically unobtainable. In the Chillagoe district the logs are delivered at the mines at a cost of from 6c. to 8c. per running foot, and the cost of converting them .into posts, caps or stretchers is 4c. per running foot.
BY MARK IRELAND
THE orebody being worked at the Mount Rex tin mine, Ben Lomond, Tasmania, is about 100 ft. in length by 70 ft. in width. A face of 15 ft. is stoped over the whole level at one operation, this hight standing without any timber.
Double lines of logs, 20 ft. in length, and from 10 in. to 1 ft. thick at the small end, are laid longitudinally, butt to butt, and breaking joint from end to end of the orebody; they are at 10-ft. centers from wall to wall. The starting logs are single for the first 10 ft., and their ends are hitched into the solid rock. These are called "runners/' and are the logs which are picked up as the level underneath is worked up. The double layer gives a better chance of picking up. Logs are then laid from the center of the orebody and at right angles to the runners, the ends being hitched into the walls.
A space, 7 ft. wide, is left open right through the center of the orebody, and a similar space through from the cross-cut leading to the shaft. The cross logs are spiked down, 4 ft. apart, to the runners. Decking, of small spars from 3 to 6 in. thick, is then laid down. Timber cribs, or "pig-styes," are next built up, 4 ft. wide, on each side of the open spaces previously referred to, forming a skeleton drive.
The pig-styes are constructed as follows: Two logs are laid parallel, 4 ft. apart, and upon them, in notches at the ends and the middle, three cross sills are laid, two more logs are laid upon them in turn, and so on until 7 ft. high in the clear is obtained. In the spaces between the logs, waste rock is filled in as fast as built. Strong caps, 12- to 14-in. timber, are then laid 4 ft. apart across from pig-stye to pig-stye. Decking is laid over these caps as on the level. Chutes and traveling ways are then built, and 1 From Engineering and Mining Journal, July 22, 1905, Vol. 80.
the surface.
This method is strong, and very cheap as compared with square sets. But little dressing is required, only an ax, saw and auger being required; any rough, but fairly straight, timber will do. An additional advantage is that no blasting, however heavy, can injure it.
| 53,026 | common-pile/pre_1929_books_filtered | minetimbering00sandrich | public_library | public_library_1929_dolma-0015.json.gz:216 | https://archive.org/download/minetimbering00sandrich/minetimbering00sandrich_djvu.txt |
IJvog9bH2mJkM7MT | Microbiology Laboratory Manual | 11
Emilie Miller, Ph.D
Growing bacteria in culture requires consideration of their nutritional and physical needs. Food, provided in the media, is broken down by cells and used for energy and building biomass. Unlike eukaryotic cells, bacteria have options when it comes to making energy, which depend not only on the type of organic molecules in the food but also on the availability of oxygen as a final electron acceptor for respiration.
Respiration is the pathway in which organic molecules are sequentially oxidized to strip off electrons, which are then deposited with a final electron acceptor. Along the way, ATP is made. For many types of bacteria, oxygen serves as the final electron acceptor in respiration. Remarkably, oxygen is not always a requirement for respiration. For bacteria that live in environments with no air, alternative electron acceptors may take the place of oxygen.
Unlike the majority of eukaryotes, bacteria have options when it comes to making ATP. Aerobic respiration and anaerobic respiration generate ATP by chemiosmosis, and some bacteria may also ferment sugars, although the oxidation is not complete and energy is left behind. Chemical by-products and end products of these pathways are detectable and serve as the basis for many biochemical tests performed to identify bacteria.
Fermentation and anaerobic respiration are anaerobic processes—meaning that no oxygen is required for ATP production. Some bacteria have the capability (meaning they produce the appropriate enzymes) to use more than one, or even all three, of these pathways depending on growth conditions.
Based on whether oxygen is required for growth, bacteria can be considered to be either aerobes or anaerobes. However, because some bacteria may use more than one pathway, there are additional categories that describe a culture’s requirement for oxygen in the atmosphere. The three major categories are:
Strict aerobe—Bacteria that are strict aerobes must be grown in an environment with oxygen. Typically, these bacteria rely on aerobic respiration as their sole means of making ATP, but some may also ferment sugars.
Strict anaerobe—These bacteria live only in environments lacking oxygen, using anaerobic respiration or fermentation to survive. For these types of cells, oxygen can be lethal because they lack normal cellular defenses against oxidative stress (enzymes that protect cells from oxygen free radicals).
Facultative anaerobe—The most versatile survivalists there are. These bacteria typically have access to all three ATP-forming pathways, along with the requisite enzymes to protect cells from oxidative stress.
Additionally, overlapping categories include:
Microaerophile—As the name implies, these bacteria prefer environments with oxygen, but at lower levels than normal atmospheric conditions. Often, microaerophiles also have a requirement for increased levels of carbon dioxide in the atmosphere and may also be called capnophiles. These bacteria make ATP by aerobic respiration and may also ferment sugars aerobically.
Aerotolerant anaerobe—These bacteria make ATP by anaerobic respiration and may also be fermentive. However, they are “tolerant” of oxygen because they may have cellular defenses against oxygen free radicals. | 630 | common-pile/pressbooks_filtered | https://openoregon.pressbooks.pub/microbiologylaboratorymanual/chapter/growth-patterns-in-broth/ | pressbooks | pressbooks-0000.json.gz:9981 | https://openoregon.pressbooks.pub/microbiologylaboratorymanual/chapter/growth-patterns-in-broth/ |
0ATOYDFEmwmwU1Yf | Hunger in the infant / by Rood Taylor. | ROCHESTER, MINN.
Cannon and Washburn,1 and Carlson and his colaborers have given us a proved method for studying hunger objectively; its time of occurrence, its intensity, its effects, and the means by which it may be produced or inhibited. They have shown that contractions of the so-called empty stomach cause the hunger sensation. These contractions depend in part on vagus tonus. They can be increased by chemical changes in the blood, but are primarily due to a gastric mechanism as purely automatic as is that of the heart.
Impulses set up by these contractions and carried to the higher centers are, in the normal consciousness, recognized as hunger. These impulses produce secondary effects such as restlessness and irritability. They increase the reflex excitability of the central nervous system, the heart beats faster, and there are changes in the vasomotor mechanism. Well fed, sedentary adults seldom experience hunger. The prime factor in their desire for food depends not on the basis of distress due to the contractions of a hollow viscus, but on "the memory processes of past experience with palatable foods." This psychic factor is appetite, and its absolute distinction from the physical factor, hunger, must be kept in mind.
Working on dogs, Patterson, in 1914, showed the gastric hunger contractions to be much more frequent and vigorous in young than in older animals. In 1915, Carlson and Ginsburg described the great intensity of hunger contractions in the human new-born. Previous to that year no productive analytic studies of the hunger sense in the human infant had been made. Appetite and hunger were not distinguished, and the sucking mechanism alone had been analyzed.
In 1888, Auerbach distinguished the infantile type of sucking from the voluntary inspiratory type employed by the adult, and in 1894 Basch, disproving the older theory of Preyer that sucking is instinctive, showed it to be entirely reflex.
1. All references to the literature will be found at the end of the article.
Czerny, in 1893, observed that an infant awakened a short time after taking his fill from the maternal breast, would again suck vigorously if placed on it, and concluded that sucking per se could not be considered as a sign of hunger. A few years later (1900) Keller wrote that, since the normal infant sleeps three hours after nursing, although its stomach is empty in two hours, the emptying of the stomach cannot be considered a positive criterion of need for food. Pies, in 1910, considered the reddening and eczema of the lower lip which occurs in undernourished infants as a sign of hunger, and referred it directly to the infant's fruitless sucking. In 1913 Schlossmann concluded from extensive observations on semistarved infants that the sensation of hunger exists only in the imagination.
Meyer and Rosenstern studied the results of starvation in the different types of alimentary disorder, recording particularly the pulse, temperature, respiration and weight changes. Rosenstern later (19111912) wrote extensively on the general subjects of hunger and inanition in infancy. These studies are all defective in that they do not distinguish the various factors concerned. Neumann, Pfaundler, Cramer, Siiszwein, Earth, and Kasahara have discussed the subject of disturbances in the food urge largely from the point of view of imperfections in the sucking mechanism.
The present studies are concerned particularly with the gastric factors in the urge for food. The major of these, the hunger contractions, was studied by means of apparatus similar to that used by Carlson. A rubber balloon of about 20 c.c. capacity attached to one end of a small soft rubber catheter is inserted into the stomach and inflated, the catheter is attached to a bromofonn manometer with a cork float and a writing pennant which records the gastric movements on smoked paper.
The material investigated included 5 premature infants weighing from 1,200 to 2,500 gm., 40 full term new-borns under 3 weeks of age, and 11 older babies, 5 between 1 and 2 months, 2 between 3 and 4 months, 3 between 4 and 6 months, and 1 boy of 2 years with a surgically induced gastric fistula made necessary by the effects of corrosive in the esophagus. The gastric movements of some of the infants were recorded only once ; on others as many as twenty observations were made.
Carlson and Ginsburg refer to the readiness with which most infants accept and retain the tube and balloon. It is naturally impossible to secure a graphic record of the stomach movements of a raging infant. Carlson and Ginsburg did their work on full term new-borns. These infants, as a rule, sleep quietly when not disturbed. The present work was carried on in a dimly lighted, quiet room. I had less difficulty when the infant was left undisturbed in his crib than when I
The older babies resent the presence of the tube, and with them it \va> often necessary to make repeated attempts to secure tracings. Some infants finally became accustomed to the presence of the tube and slept quietly, particularly if the experiments were conducted in the evening. Most of the tracings on the 2-year-old boy with the gastric fistula were made when he was awake. The greatest problem was to keep him sufficiently interested to prevent crying and restlessness and at the same time to prevent riotous hilarity. In his case the balloon was introduced directly through the fistula.
out in these studies.
Does the presence of the balloon in the stomach act mechanically to produce gastric contractions ? Carlson states definitely that it does not, and gives the following reasons for his belief :
or intensity.
The results of this work fully confirm Carlson and Ginsburg's report that the stomach of the new-born infant exhibits greater hunger contraction than does that of the adult. The intervals between the contraction periods are often less than five minutes and usually not longer than from ten to twenty minutes. The first contraction period after a nursing is apt to consist of from five to twenty separate contractions and to last from two to eight minutes. The succeeding contraction periods frequently endure from thirty minutes to an hour or even longer. The duration of each contraction is about twenty seconds. In many of the infants the contraction time of the more powerful contractions, especially in those periods ending in partial tetanus, was about eighteen seconds. Except in the first contraction period after a nursing, endings in partial tetanus were frequently observed. Partial tetanus is sometimes present before the close of the period. With the apparatus used, the force of the single contractions usually sufficed to raise the column of bromoform 2 to 3 cm. During partial tetanus the bromoform may be raised 5 cm.
hunger contractions of the somnolent, prematurely born infant. The stomach of such an infant is in a state of nearly continuous contraction. The individual contractions require about the same length of time for their completion and are as powerful as those of the full term infant. In a tracing begun forty minutes after a feeding of 15 gm. of breast milk to a premature baby (Baby 5) weighing 1,510 gm., the record appears very like that obtained by Rogers from the crop of a pigeon in the second day of starvation. The periods of contraction last two or three minutes, with intervening periods of quiescence of about the same length. The individual contractions last twelve to fifteen seconds and raise the bromoform column 3 to 4 cm. Partial tetanus is frequent. Xine days later, when the infant was receiving more food, in spite of the fact that he had not gained in weight and that the tracing was begun five hours after his last feeding, the record obtained was similar to those from other infants.
Are the hunger contractions more frequent or more powerful in cyanosed infants? May they furnish a stimulus for crying with consequent better aeration of the lungs? In two such cases no significant increase or decrease in the hunger contractions could be observed. No records were taken from any cyanosed premature infants, although such infants are frequently slightly blue for the first few days.
Carlson, working on the adult, was unable to produce hunger contractions by any sort of stimulus acting directly in the mouth or in the stomach, except that he occasionally could, by suddenly distending the stomach, produce a few transitory contractions. He found, uniformly, that the only effect of such local stimulation was inhibitory. In general, the taste of salt, sour, bitter, or sweet ; or the chewing of agreeable, disagreeable, or indifferent substances, all produce temporary inhibition of the gastric contractions. Chewing palatable foods by the adult when hungry causes an inhibition, made more lasting by the flow of appetite juice in the stomach.
Carlson found that acid and alkaline solutions, food and liquids in the stomach, all inhibit the hunger contractions. Inhibition from the stomach is less transitory than that from the mouth. Boldyreff showed that the periodic contractions of the empty stomach were inhibited by the presence of acid in the intestine. Brunemeier and Carlson completed and enlarged this work. They demonstrated inhibition from the presence of gastric juice or acid chyme in the small intestine. This inhibition from the stomach and intestine is reflex, partly through Auerbach's plexus, but mainly through the long reflex arc with the efferent path to the stomach muscles through the splanchnics.
Inhibition from the mouth is not present in the frog (Patterson). Carlson, who suspects that such inhibition involves conscious cerebral processes, has suggested experiments in infants to settle the point.
Repeated trials with breast milk, sugar water, common salt, quinin, and lemon juice in the mouths of premature and new-born infants in my study failed to produce inhibition of hunger contractions.
In general I obtained the same results in an infant of 8 weeks. A transitory inhibition occurred occasionally when sugar water was placed in his mouth. In none of the infants did chewing or sucking on the thumb or tube produce inhibition. Nor did such movements or the presence of sugar, breast milk or other substances in the mouth induce hunger contractions.
The boy of 2 years showed inhibition when sugar or protein milk (his diet at the time) was placed in his mouth. Quinin, dilute hydrochloric acid, small amounts of sugar water, table salt in crystals or solution, did not inhibit. Benzosulphinidum solution inhibited twice. It was not used subsequently. The sight of sugar did not inhibit. He began to cry when he saw his bottle if the latter were not given him immediately. Conseqeuntly the effect of his seeing the bottle on the hunger contractions could not be registered. During the periods of quiescence the sight of the nurse who fed him did not induce hunger contractions, although he began to whine and tease when she entered the room.
Apparently inhibition from the mouth was produced by those substances only which the child regarded as food. Quinin very evidently made a profound sensory impression, but did not inhibit the contractions. Dilute hydrochloric acid did not inhibit, while unsweetened protein milk (which is slightly sour) did.
Carlson's hypothesis as to the need of conscious cerebration for the production of inhibitory reflexes from the mouth would appear to offer the correct explanation. It seems to be agreed that the new-born infant leads a subcortical reflex existence (Soltmann-Cramer). Kussmaul and Thiemich note that the new-born infant accepts sugar and rejects salt, food that is sour and bitter — action which is almost certainly purely reflex on the part of the infant.
My work shows that when 20 c.c. of water or milk are introduced into the stomach during a contraction period inhibition follows invariably. This was found true in infants of all ages. With small amounts of water the inhibition often lasted only three or four minutes, when the contraction period would be resumed.
On the other hand, it was not unusual to recover from 15 to 40 cm. of clotted milk through the stomach tube even an hour after vigorous hunger contractions had begun. This is a considerable portion of the infant's meal, and in these cases would represent from one-sixth to one-fourth of his total intake at the previous feeding. Soltmann showed that the inhibiting nervous mechanism of the heart is much less effectual in the new-born infant than in later life. It seems possible
that the nervous apparatus for the inhibition of the gastric hunger movements may likewise be immature. Or the tissue hunger may be so great as to overcome any but the strong inhibition of a heavily laden stomach and duodenum.
The vagi form the sensory pathway from the stomach to the brain. The first reflex centers are the sensory nuclei of the vagi in the medulla. A second center, possibly that for conscious hunger, is located in the optic thalami. Rogers has shown that the picking reflex in the pigeon (analogous to the sucking reflex in the babe) is abolished on removal of the thalami.
The reflex irritability (as indicated by the knee jerk) is increased synchronously with each hunger contraction (Carlson). No observations have been made on the infant's knee jerks during the hunger state ; but Zybell has shown that the electrical irritability increases during the first eighteen hours of starvation.
Let us summarize the events from the close of one meal till the end of the next. The infant sleeps. The upper stomach musculature maintains a tonic grasp on the contained food. The pyloric antrum is traversed by peristaltic waves (Cannon). The stomach gradually empties. The point of origin of the peristaltic waves rises higher and higher. The tonus rhythm of the fundus begins. The stomach empties itself more completely, the tonus rhythm becomes more intense, and the first hunger contractions appear (Rogers and Hardt).
The first contraction period is apt to be short. After a wait of perhaps twenty minutes a longer and more intense hunger period arrives ; then another and another. The infant's sleep becomes lighter. He is more easily awakened by external stimuli or by gastric discomfort. He is put to the breast, nurses vigorously, becomes fatigued (Schmidt, Cramer, Pfaundler), or experiences satiety from distention (Neisser and Brauning) and again goes to sleep.
What constitutes the hunger state? Does it result from the summation of impulses with an increasing psychic and reflex irritability? The evidence is to the contrary. The increase in the reflex excitability is synchronous with the contraction phase of the stomach, and is absent in the intervals between the contractions. In the infant who has been some hours without food the hunger contractions are nearly continuous, and it would be expected that the reflex excitability would be nearly continuously high.
In the absence of hunger contractions the infant often sucks vigorously on the tube attached to the balloon. The receptive mechanism for the institution of the sucking reflex is so delicate that it is impossible to provide, artificially, a minimal stimulus. During the hunger state, when presumably a rapid succession of hunger contractions maintains a low reflex threshold, there may often be observed a succession of
each movement providing the necessary stimulus for its successor.
The lay mind is prone to think that the crying infant is hungry. Comby and Czerny and Keller believe that hunger is a minor cause of crying. Rosenstern notes that in hunger young babies are usually quiet, but that the older infants cry more. Schlossmann remarks that the normal infant endures hunger well.
Observations on this point extending over sixteen months of study of the hunger sensation lead me to believe that in normally thriving breast fed infants, except when more than three or lour hours have elapsed since the last feeding, neither the hunger contractions themselves nor the increased irritability due to them are ordinarily immediate factors in the production of crying. Young infants sleep throughout strong contraction periods. Older infants often do the same, and are frequently quiet even from twelve to sixteen hours after a feeding. Mental factors produce crying at a very early age. And the fact that crying ceases when food or water is administered may only mean that the infant's attention is diverted to the performance of a pleasurable act.
It may be noted in this connection that the 2-year-old boy was happier when allowed to take food into his mouth, and that his outlook on life was much more cheerful on days when he could take nourishment by mouth than on other days when the esophageal constriction increased, and it became necessary to introduce the food through the gastric fistula. This feeding through the fistula was without pain, and the child submitted to it with some pleasure.
What is the time interval between feeding and the first appearance of gastric hunger contractions? Ginsburg, Tumpowsky and Carlson studied this point in thirty normal breast fed infants under 4 weeks of age. They gave no data as to gain in weight and did not determine the amount of food taken, but stated that the babes nursed till satisfied. They found the average time between nursing and the appearance of hunger contractions to be two hours and forty minutes, with a minimum of two hours and twenty minutes and a maximum of three hours and thirty minutes. My observations on twelve new-born infants under like conditions yielded these results ; a minimum of one hour and thirty minutes, a maximum of three hours and thirty minutes, and an average of about two and one-half hours.
Many infants in the first two weeks do not receive a sufficient supply of breast milk. This is particularly apt to be true of the time the babe and the mother remain in the hospital. Consequently, observations made under the conditions so far outlined may be misleading. Table 1 (A, B and C) gives the results of all satisfactory tracings obtained from normally thriving babies on whom sufficient data as to food intake and weight gain were obtained.
The time required for the development of hunger in the premature infant is noticeably short. In the case of the full term ne\v-borns the figures obtained agree fairly well with those given by Ginsburg, Tumpowsky and Carlson, but are definitely greater than those obtained by me (mentioned in a preceding paragraph) from infants whose food intake was net accurately known.
The time required for the development of hunger in any one infantis fairly constant over a short period of time, provided the amount and kind of food is not changed. This conclusion rests not only on the results shown in Table 1, but on a dozen other observations on infants whose feeding conditions remained constant during the time in which studies were made.
With the older infants difficulty in maintaining quiet, after the insertion of tube and balloon, limits the number of observations which give positive evidence as to the first appearance of hunger contractions. Many less successful observations on healthy, normally developing infants yield this negative evidence that in such infants more than a month old I did not observe the development of hunger before the end of three hours.
It should be noted further that the contraction period, the first appearance of which is recorded in Table 1, is the first one to develop after feeding. This period is usually short and is not made up of forceful contractions. With Infants J. and A. more intense and more nearly continuous contractions did not begin for four and four and a half hours, respectively.
Habits as to feeding interval affect the time required for the development of hunger chiefly as they influence the emptying time of the stomach. It has been shown that the speed of gastric emptying is proportional to the length of time during which the individual has been without food (Tobler, Haudek and Stigler), and that large feedings are emptied with relatively greater rapidity than small ones (Tobler and Bogen). Habits undoubtedly exert a more powerful influence or. the mental factors associated with appetite than on hunger itself.
Tables 2, 3 and 4 illustrate the shorter time required for the development of hunger in infants with chronic nourishment disturbance, and indicate that the presence of hunger contractions is not in itself evidence that the stomach is ready for food.
In the columns headed "Remarks" in Tables 1, 2, 3 and 4, there are notes as to material recovered with the stomach tube after the onset of gastric hunger contractions. In normal babies, however, there probably does exist a relation between the emptying time of the stomach and the interval for the development of hunger.
been made either with the relatively stiff catheter, the stomach tube.
or the Roentgen ray. The flexible tube introduced by Rehfuss should replace the catheter for this purpose ; it was used in my work. The literature contains no reports of the time required for gastric digestion in the premature infant. The emptying time in normal breast-fed infants under 1 week is usually less than one hour (Leo). The Roentgen-ray observations of Ladd and of Tobler and Bogen would indicate that in normal breast-fed infants the stomach is frequently not empty until after two to three hours. The figures obtained with the use of the stomach tube by Epstein, Czerny, Keller and Cassel indicate a delayed emptying time in gastro-intestinal disease.
Major, using the Roentgen ray, finds the emptying time delayed in dyspepsia, but accelerated in decomposition. With the same method Pisek and LeWald found the emptying time to be shorter in infants with chronic disturbances of nutrition.
These last findings, taken in conjunction with the already quoted reports of Tobler, and of Haudek and Stigler, that the emptying time is shortened by hunger, are suggestive of the results here obtained experimentally ; that is, the greater gastric hunger contraction in infants with chronic nourishment disturbance.
infants, but the contractions become much more intense. Nov. 10,
1916, the 2-year-old boy (Table 2), whose weight in spite of a calorically sufficient intake had remained stationary, and whose temperature had been irregular, developed fever and diarrhea. After eight hours of starvation, with temperature normal, the graphic record of his gastric activities resembled those of the starving pigeon and of the premature infant already mentioned. The contractions were continuous and required only twelve seconds for their completion. Next day the child was put on protein milk and thereafter improved.
evidence ol hunger periods until 5 p. m.
leave most rapidly. In Infants A. and W. the time interval for the development of hunger contractions was much longer when they received low fat and high carbohydrate, and shorter when they received high fat and low carbohydrate. This would be paradoxical if the gastric hunger contractions depended exclusively on the emptying time.
ing of the stomach.
The interval necessary for the development of hunger depends in part on the form of nourishment and is shortest with that food which least satisfies the infant's tissue need (Table 4). The question as to whether the rapid development of hunger in qualitatively poorly
nourished infants depends on the administration of food deficient in carbohydrate in particular, or on the giving of food poorly tolerated in general, is not answered. Records of the gastric contractions in infants suffering from the chronic nourishment disturbance due to long continued carbohydrate overfeeding (the "Mehlnahrschaden" of Czerny) would help to settle this point.
contraction period
Attention has already been called to the heightened electrical reactions found by Zybell in hungry infants. I also wish to mention the findings of Finklestein, Thiemich and Japha that the electrical irritability is frequently heightened in artificially fed infants, and of Czerny and Moser that there is an increase in the electrical irritability of infants suffering with "Mehlnahrschaden." It is possible that the heightened electrical irritability in all depends on the increased hunger contractions due again in part to the constant chemical stimulation reaching the stomach from the semistarved tissues.
Most premature infants and many young infants nurse poorly. The consequent effect on lactation and on the babe's nourishment is serious. An extensive literature on this subject has been developed in German, but there is surprisingly little in French and in English.
In 1888 Auerbach described the infantile manner of sucking, which depends on the chewing muscles, and Escherich showed its teleologic importance. The reflex paths and center in the medulla were demonstrated in 1894 (Basch). Cramer, Suszwein, Finklestein, Rott, Rosenstern, Barth and Kasahara have further studied the question and report results which in general support the theory that the inability to nurse well is to be attributed primarily to an imperfect nervous mechanism and not to muscular weakness.
examples.
The first baby (Baby M.), weighing 2,700 gm. at birth and presenting no anatomic peculiarities, took very little from the mother's breast during the first three weeks, although sufficient milk was expressed therefrom to feed the baby and to complement the feedings of other babies.
The second infant (Baby T.), aged 3 months, had weaned himself from the breast, had developed dyspepsia and atrophy on artificial feeding, and could be made to take his food from the bottle only with great difficulty. He seemed able to fix his attention on anything other than the act of feeding.
In these infants as well as in the five prematures, and in one typical case of congenital myxedema, hunger contractions of at least normal force and duration were present. At the time they were studied, none of the infants was able to nurse successfully. In all, the sucking reflex was qualitatively present.
This study does not solve the problem as to the causation of feeble nursing, but does limit the field of possibilities by excluding derangements of the primitive hunger apparatus.
Carlson reports Rupp's finding that hunger contractions persist during the fever excited by the administration of typhoid vaccine. The boy with the gastric fistula contracted typhoid fever from a carrier. Tracings taken while his rectal temperature ranged between 104.4 F. and 105 F., show the presence of hunger contractions.
Carlson and Ginsburg found hypertonicity and hypermotility in the stomachs of two infants with pylorospasm and stenosis. From a six weeks' old infant (Baby S.) with pyloric stenosis, I obtained records which agree with Carlson and Ginsburg's description of periods of tetanus lasting several minutes interspersed with vigorous contractions of normal duration.
Carlson suggests that pylorospasm and stenosis may be an expression of gastric hypermotility. His cases were seen late, as was the one here reported. In the absence of tracings taken at the beginning of the disease, it is likely that the hypermotility results from the inanition following the obstruction at the pylorus. And without definite knowledge that the stomach was washed empty, the long periods of tetanus observed may represent the so-called visible gastric peristalsis.
occur in young infants.
5. Inhibition of the hunger contractions from the mouth in older infants is present only as the result of stimuli, which the babe has learned to recognize as food. It does not occur with substances producing equally strong sensory impressions, but which are not considered by the infant as food.
9. Successive automatic sucking movements — • each sucking act serving as the stimulus for its successor — are present during the hunger state, when the reflex threshold is kept almost constantly low by a rapid succession of hunger contractions.
narily an immediate cause of crying.
11. The average time required for the development of hunger in healthy infants gaining in weight and receiving a known sufficient amount of food is, in prematures, under one month, one hour and forty minutes, with a maximum of two hours and twenty minutes and a minimum of forty minutes; in full term infants under two weeks, two hours and fifty minutes, with a maximum of four hours and a minimum of two hours; in infants from two weeks to four months.
12. The time required for the development of hunger in any one infant is fairly constant over a short period of time provided the amount and kind of food is not changed (Tables 1, 2, 3 and 4).
15. Hunger contractions occur in these infants long before the stomach has emptied. Consequently their presence is not in itself an indication that the stomach is ready for food.
16. The feeble nursing exhibited by most prematures and by many older infants is not due to derangement of the primitive hunger apparatus. Hunger contractions are present and of normal intensity in such infants.
tractions in infants with pyloric stenosis.
I wish to express my sincere thanks to Dr. A. J. Carlson of the University of Chicago for suggestions which aided materially in carrying out these studies; to Dr. E. P. Lyon and Dr. A. D. Hirschf elder for the loan of apparatus from the departments of physiology and pharmacology ; to Dr. F. H. Scott and Dr. F. B.. Kingsbury for advice and assistance in the construction of apparatus ; to Dr. F. W. Schultz for the use of material from the Infant Welfare Clinic; to Dr. N. O. Pearce, teaching fellow in pediatrics, and to head nurses Barber and Wenck, who cheerfully assisted in preparing the little patients for examination.
To my chief, Dr. J. P. Sedgwick, who first suggested this problem, and who allowed the free use of his material in the service at the university hospitals, I wish to express my grateful appreciation for constant stimulating interest and helpful suggestions.
Stomach, Arch. Soc. de biol.. 1905. 11, 1. Quoted by Carlson, Footnote 9.
5. Brunemeier, E. H., and Carlson, A. J. : Contributions to the Physiology of the Stomach; XIX. Reflexes from the Intestinal Mucosa to the Stomach, Am. Jour. Physiol., 1914-1915, 36, 191.
10. Carlson, A. J. : Contributions to the Physiology of the Stomach ; II. The Relation Between the Contractions of the Empty Stomach and the Sensation of Hunger, Am. Jour. Physiol., 1912-1913, 31, 175.
11. Carlson, A. J. : Contributions to the Physiology of the Stomach; III. The Contractions of the Empty Stomach Inhibited Reflexly from the Mouth, Am. Jour. Physiol., 1912-1913, 31, 212.
12. Carlson, A. J.: Contributions to the Physiology of the Stomach; IV. The Influence of the Contractions of the Empty Stomach in Man on the Vasomotor Center, on the Rate of the Heart Beat, and on the Reflex Excitability of the Spinal Cord, Am. Jour. Physiol., 1912-1913, 31, 318.
13. Carlson, A. J., Orr, J. S., and McGrath, L. W. : Contributions to the Physiology of the Stomach ; IX. The Hunger Contractions of the Stomach Pouch Isolated According to the Method of Pawlow, Am. Jour. Physiol., 1914, 33, 119.
14. Carlson, A. J., and Ginsburg, H. : Contributions to the Physiology of the Stomach; XXIV. The Tonus and Hunger Contractions of the Stomach of the New-Born, Am. Jour. Physiol.. 1915, 38, 29.
15. Carlson, A. J., and Ginsburg, H. : Contributions to the Physiology of the Stomach ; XXX. The Tonus and Contractions of the Empty Stomach of Infants With Congenital Pyloric Stenosis, Pylorospasm and Chronic Vomiting (Merycism), Am. Jour. Physiol., 1915, 39, 310.
28. Ginsburg, H.. Tumpowsky, I., and Carlson, A. J. : The Onset of Hunger in Infants After Feeding; A Contribution to the Physiology of the Stomach, Jour. Am. Med. Assn., 1915. 64, 1822.
29. Haudek, M., and Stigler, R. : Radiologische Untersuchungen iiber den Zusammenhang zwischen Austreibungzeit des normalen Magens und Hunger gefiihl, Arch. f. d. ges. Physiol., 1910, 133, 145.
33. Ladd, M.: Gastric Motility in Infants as Shown by the Roentgen Ray, AM. JOUR. CHILD. Dis., 1913, 5, 345. Ibid., The Influence of Variations of Diet on Gastric Motility in Infants, Arch. Pediat., 1913, 30, 740.
Wchnschr., 1888, 25, 981.
35. Luckhardt, A. B., and Carlson, A. J. : Contributions to the Physiology of the Stomach ; XVII. On the Chemical Control of the Gastric Hunger Mechanism, Am. Jour. Physiol., 1914-1915, 36, 37.
Therap. Monatsh., 1893, 7, 220. Abstr. in Arch. f. Kinderh., 1897, 22, 152.
40. Patterson, T. L. : Contributions to the Physiology of the Stomach ; XIII. The Variations in the Hunger Contractions of the Empty Stomach With Age, Am. Jour. Physiol., 33, 423.
41. Patterson, T. L. : Contributions to the Physiology of the Stomach ; XXXVI. The Physiology of the Gastric Hunger Contractions in the Amphibia and the Reptilia, Am. Jour. Physiol., 1917, 42, 56.
1894, 38, 68.
46. Quest, R. : Ueber den Einfluss der Ernahrung auf die Erregbarkeit des Nervensystems im Sauglingsalter, Wien. klin. Wchnschr., 1906, 19, 830. Quotes : Finklestein : Fortschr. d. med., 1902, 20; Thiemich : Revue d' hyg. et de med. d. inf., 1903, 2; Japha, A.: Ueber den Stimmritzankrampf der Kinder. Berl. klin. Wchnschr., 1903, 40, 1126.
Assn., 1914, 63, 11.
49. Rogers, F. T., and Hardt, L. L. J. : The Relation Between the Digestion Contractions of the Filled, and the Hunger Contractions of the "Empty" Stomach, Am. Jour. Physiol., 1915, 38, 274.
There is apparently a gastric element in appetite. The contractions of the stomach institute hunger. Its profuse and rich secretion causes an entirely different sensation — not painful, but pleasant. Carlson concludes that the appetite or psychic gastric juice described by Pawlow1 stimulates sensory nerve endings in the gastric mucosa. The resulting sensation resembles that which follows the first few mouthfuls of good food at a meal to which one has come hungry, and directs the flow of consciousness toward the matter of taking food.
Pediatric literature contains many references to this secretion. Bauer and Deutsch found no gastric juice in the baby's stomach after it had reached eagerly for its bottle. Pfaundler noted that in babes who nursed actively the stomach emptied sooner, and the degree of acidity attained was higher than in babes who were fed passively or through the tube. Cohnheim and Soetbeer, working with gastrotomized new-born pups, obtained juice containing hydrochloric acid even when the pups nursed on nonlactating breasts. A. H. Meyer found a great variation in gastric acidities in the same child and conjectured that the variations might depend on the presence or absence of Pawlow's appetite juice. Schmidt writes that the infant on the breast works and stimulates the secretion of gastric juice. Meisl advocates the use of a pacifier before meals to cause the flow of appetite juice. Bogen, whose material included a 31/2-year-old boy with a stenosed esophagus and gastric fistula, concludes that psychic secretion of gastric juice does occur. Nothmann, in 1909, formally investigated the question of the secretion of appetite juice by the infant's stomach, and concluded that it took place even immediately after birth. Rosenstern advised the use of pepsin and hydrochloric acid to stimulate the appetite of infants who nurse poorly. Bonniger could find in pups no relation between the kind of food and the secretion of gastric juice.
With the exceptions of the work done on pups, and Bogen's work on a S^-year-old boy, the foregoing is all brought into question because it relies on the use of the ordinary catheter or stiff stomach tube, which
does not permit accurate quantitative studies. A still more serious criticism, and one which leaves the whole subject open, is that in none of the quoted work is the possibility of a continuous secretion of gastric juice sufficiently taken into account.
In 1888 Leo found free hydrochloric acid in the stomachs of unfed new-born babes, and noted that in older infants the stomach was rarely entirely empty, so that he could usually recover a few drops of thick, yellowish acid fluid. He washed out the stomach and again inserted the tube and then obtained only wash water from the preceding washings. Consequently Leo concluded that the acid juice obtained by him from the "empty" stomach was the gastric juice remaining from the last meal, concentrated by the absorption of water. Wohlmann reported that the secretion of the infant's empty stomach is viscid, colorless, glassy, and without free hydrochloric acid. Wohlmann took his specimens from one to two hours after feeding. The teachings of Pawlow that gastric secretion depends on appetite or on food or other stimuli in the stomach impressed the medical mind so deeply that until the present decade all gastric secretion was interpreted in the light of his investigations. A. H. Meyer concluded that the passage of the stomach tube does not excite the secretion of acid gastric juice. Pawlow's published work supports the same conclusion. Engel reports a 4-week-old babe with pyloric stenosis and a jejunal fistula. From this infant, who was fed through the fistula, Engel obtained by way of the esophagus from 60 to 200 c.c. of gastric juice daily. The total acidity of this juice ranged from 60 to 70 and was nearly entirely made up of free hydrochloric acid. Engel was unable to explain his findings except on the basis of a pathologic hypersecretion, which he thought might have caused the pyloric stenosis. Alfred F. Hess, in 1913, showed that the stomach of the unfed new-born babe secretes a highly acid juice, and he concluded further that saliva does not act as a stimulus to the production of such juice. He was unable to determine a relationship between the amount of sucking and the amount of juice secreted. Sedgwick recovered acid stomach and duodenal contents three and four hours after nursing. In 1905 Boldyreff reported continuous secretion of the gastric glands in starving dogs. Ten years later Fowler, Rehfuss and Hawk concluded that, in man, the gastric glands are never idle, while Carlson demonstrated the continuous secretion of gastric juice in the empty stomach of normal adults. Referring to its secretion during the hunger state, Carlson calls it hunger juice.
It is evident that the determination of the secretion of an appetite juice in the infant's stomach must be made in conjunction with the determination of its continuous secretion.
Rehfuss, combined with any simple syringe for gentle aspiration, makes
an excellent instrument for the study of the physiology of the stomach of the infant. A smaller tip can be made for those infants who cannot swallow the ordinary tip. With this apparatus I have repeatedly recovered from the infant's stomach the entire 30 to 50 c.c. of water introduced into it and never have lost more than 2 c.c. in the washing. Furthermore, large, thick, gelatinous clumps of mucus and curd are removed without difficulty.
In order to avoid, as far as possible, contaminating the gastric juice with saliva, and to permit the carrying out of sham feeding, I converted a No. 21 F. soft rubber catheter into an outer casing for the Rehfuss tube. When in place this outer casing terminates internally in the esophagus, and externally with a suction apparatus. The whole is explained in the accompanying illustration, which is one-half actual size.
actual size.
The experimental procedure was as follows: If the babe fasted allnight, he was given water at 5 a. m. in quantity equivalent to his usual feeding. When the stomach was examined a few hours later, milk remains were never found. If the period without food were shorter, his stomach was thoroughly washed out and observations begun an hour later.
If no aspiration is applied to the stomach tube during the half hour, the amount obtained is usually less than 1 c.c. The usual procedure was to insert the tube, exert suction to empty the stomach of any content, then allow the tube to remain one-half hour without suction, and
collect the specimen, if any. Repeat the procedure, exerting gentle suction every two and one-half minutes and collect the specimen. Exert suction in the same way during a third half hour while the sham feeding progresses. The final two specimens only are listed in the accompanying table.
As a rule, no secretion was obtained for five minutes after the insertion of the tube. On one occasion gastric juice containing free hydrochloric acid was obtained within two minutes of the time at which introduction of the tube began (Baby A.). This is less than the latent time usually required by the gastric glands (Carlson, Pawlow) and is further evidence that the secretion here obtained was not produced artificially by the apparatus.
To stimulate an appetite secretion, the babe was given a pacifier threaded over the tube, or, the food to which he was accustomed was administered by a medicine dropper, or, with the artificially fed babes, from their usual nursing bottle. The infant always sucked vigorously during this procedure. If the babe sucked before sham feeding began, it has been noted in the table. As a rule, the babes slept or were quiet and did not suck, except after the beginning of the sham feeding. The presence of the tube seemed to discommode these babes very little. There certainly was no psychic excitement to depress the action of the gastric glands while the babes were smacking and sucking over their food.
In three cases only, as noted in the table, did food reach the stomach. Strictly speaking, neither these instances nor the specimens which contained blood should be considered as offering evidence on either the subject of "hunger" or "appetite" gastric juice. The only demonstrable effect of the blood, which was never present in more than a trace, was to lower the acid titration values. On the three occasions on which milk reached the stomach, larger amounts of secretion was obtained.
The titrations were done against tenth-normal sodium hydroxid, using di-methyl-amino-azobenzol and phenolphthalein as indicators. The hydrogen-ion concentrations were done by the gas chain methoG. I wish to thank Dr. J. F. McClendon for his courtesy in allowing the use of his apparatus.
The "appetite" gastric juice is characterized by its relatively profuse secretion and high acidity. Neither characteristic was present in the juice obtained after sham feeding in these infants. On the contrary, the juice obtained differed little in character and quantity from that obtained before sham feeding was begun.
It will be seen that the empty stomach of the infant continuously secretes a juice which at times is as acid as that of the adult, and that the infant's stomach does not secrete an "appetite" or psychic juice.
Reiche has demonstrated the absence of a duodenal reflux into the infant's stomach. The present findings support his conclusion. What, then, becomes of this continuous secretion under circumstances such as enforced therapeutic starvation from twenty-four to forty-eight hours? Pfaundler has conjectured that at the close of digestion the alkaline secretion of the pyloric glands gradually neutralizes the acid content of the stomach. I cannot support this view. The finding of a greater quantity of juice when a more continuous suction is maintained, the frequent absence of juice when the tube is first inserted, and Sedgwick's finding that the young infant's duodenal contents are acid, favor the conclusion that at least a portion of this juice makes its way into the intestine.
It seems probable, therefore, that the secretion of the alkaline pancreatic and intestinal juices, which in the adult regurgitate into the stomach, as demonstrated by Boldyreff, and lower the acidity of the juice in the stomach (Carlson, Rehfuss and Hawk and Boldyreff), is, in the infant, relatively deficient.
The hunger juice is delivered through the tube intermittently. The most profuse secretion is, as a rule, associated with the higher acidities ; this is also true in the adult (Carlson). The largest amounts were obtained from one of the unfed new-born babes and from the older infants. It is readily seen that the stomach of the starving infant can secrete from SO to 200 c.c., or more, of highly acid juice daily. This equals the amount Engel obtained from his case of pyloric stenosis, which has served as the clinical basis for the theory that hyperacidity or hypersecretion of the gastric juice is an etiologic factor in that disease.
Furthermore, this demonstration of the capacity of the infant's stomach to secrete a highly acid juice, makes it probable that the low acid values found during gastric digestion of milk are in part due to its binding power for acid (Aron), and in part due to the relatively slight stimulation which it exerts on the gastric glands (Pawlow, Moore and Allanson). Huenekens found a hydrogen ion concentration of 174 X 10'r' in a 9i/2-months-old infant after a meal of soup and vegetables. Most of his results were lower, however. No such studies have been made in younger infants.
Experience in the clinic of the University of Minnesota and in other clinics (Rott) has proved the advantage which is gained in feeding the premature infant by tube. Theoretical objections to the use of
early infancy.
Allaria points out the chemical and mechanical advantages of having the milk well mixed with saliva, and estimates that the infant secretes an amount equal to from 10 to 20 per cent, of the ingested food. The tube-fed infant may do without this secretion in part or altogether, but there is no evidence that his gastric secretion is less than that of the actively nursing babe.
What light does this study throw on deprivation of food as a therapeutic agent? In infancy such a measure finds its chief field in acute alimentary disorders and summer diarrheas. The significant fact is that in hunger the infant's stomach secretes continuously, but with intermittent intensity, a highly acid juice, which at least in part flows into the small intestine where it may play a disinfecting or detoxicating role.
SUMMARY
1. Description of an apparatus by which sham feeding can be carried out and gastric juice collected under conditions which give positive evidence of the amount secreted.
2. There is no appetite or psychic secretion of gastric juice in the young infant. This disproves the present view, which is based on insufficient experimental evidence.
does not occur.
6. The theoretical objections to tube feeding in prematures because of the lack of stimulation of an appetite gastric juice are not valid. However, a disadvantage may lie in this : that such feeding precludes the usual admixture of the milk with saliva.
Therapeutic starvation in acute alimentary disorders and in summer diarrheas may owe its success in part to the heightened tonus of the alimentary tract, and in part to the pouring out of highly acid detoxicating and disinfecting gastric juice into the small intestine.
REFERENCES
1. Allaria, G. B. : Ueber die Wirkung des Speichels im Anfangsstadium der Verdauung beim Saugling. Jahrb. f. Pediatria, 1911, 19, 10. Abstr. in Arch. f. Kinderh., 1911, 59, 129; ibid., Quanta saliva secerne il lattante durante la poppata? Riv. di clin. pediat, 1912, 10, 439.
Jahrb. f. Kinderh., 1914, 79, 288.
3. Bauer, L., and Deutsch, E. : Das Verhalten der Magensaure, Motilitat und Resorption bei Sauglingen und Kindern unter psysiologischen und pathologischen Verhaltnissen. Jahrb. f. Kinderh., 1898, 48, 21.
14. Meisl, A. : Ueber die Beziehungen zwischen Appetit und Magensaftsekretion. Wien. klin. Rundschau., 1907, No. 49. Quoted by Uffenheimer : Ergebn. d. inn. Med. u. Kinderh., 1907, 2, 271.
quoted by Czerny and Keller: Des Kindes Ernahrung, p. 62.
20. Rehfuss, M. E., and Hawk, P. B.: Direct Evidence of the Secretion of a Gastric Juice of Constant Acid Concentration by the Human Subject. Jour. Am. Med. Assn., 1914, 63, 2088.
AN INITIAL PINE OF 25 CENTS
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| 10,442 | common-pile/pre_1929_books_filtered | hungerininfant00taylrich | public_library | public_library_1929_dolma-0007.json.gz:3091 | https://archive.org/download/hungerininfant00taylrich/hungerininfant00taylrich_djvu.txt |
6FmCP99s3ohDaLP- | 10.6: Measuring Stellar Masses Part 2 | 10.6: Measuring Stellar Masses Part 2
Learning Objectives
By the end of this section, you will be able to:
- Distinguish the different types of binary star systems
- Understand how we can apply Newton’s version of Kepler’s third law to derive the sum of star masses in a binary star system
- Apply the relationship between stellar mass and stellar luminosity to determine the physical characteristics of a star
The mass of a star—how much material it contains—is one of its most important characteristics. If we know a star’s mass, as we shall see, we can estimate how long it will shine and what its ultimate fate will be. Yet the mass of a star is very difficult to measure directly. Somehow, we need to put a star on the cosmic equivalent of a scale.
Luckily, not all stars live like the Sun, in isolation from other stars. About half the stars are binary stars—two stars that orbit each other, bound together by gravity. Masses of binary stars can be calculated from measurements of their orbits, just as the mass of the Sun can be derived by measuring the orbits of the planets around it (see Orbits and Gravity in Chapter 2).
Binary Stars
Before we discuss in more detail how mass can be measured, we will take a closer look at stars that come in pairs. The first binary star was discovered in 1650, less than half a century after Galileo began to observe the sky with a telescope. John Baptiste Riccioli (1598–1671), an Italian astronomer, noted that the star Mizar, in the middle of the Big Dipper’s handle, appeared through his telescope as two stars. Since that discovery, thousands of binary stars have been cataloged. (Astronomers call any pair of stars that appear to be close to each other in the sky double stars , but not all of these form a true binary, that is, not all of them are physically associated. Some are just chance alignments of stars that are actually at different distances from us.) Although stars most commonly come in pairs, there are also triple and quadruple systems.
One well-known binary star is Castor, located in the constellation of Gemini. By 1804, astronomer William Herschel, who also discovered the planet Uranus, had noted that the fainter component of Castor had slightly changed its position relative to the brighter component. (We use the term “component” to mean a member of a star system.) Here was evidence that one star was moving around another. It was actually the first evidence that gravitational influences exist outside the solar system. The orbital motion of a binary star is shown in Figure \(\PageIndex{1}\). A binary star system in which both of the stars can be seen with a telescope is called a visual binary .
Edward C. Pickering (1846–1919), at Harvard, discovered a second class of binary stars in 1889—a class in which only one of the stars is actually seen directly. He was examining the spectrum of Mizar and found that the dark absorption lines in the brighter star’s spectrum were usually double. Not only were there two lines where astronomers normally saw only one, but the spacing of the lines was constantly changing. At times, the lines even became single. Pickering correctly deduced that the brighter component of Mizar, called Mizar A, is itself really two stars that revolve about each other in a period of 104 days. A star like Mizar A, which appears as a single star when photographed or observed visually through the telescope, but which spectroscopy shows really to be a double star, is called a spectroscopic binary .
Mizar, by the way, is a good example of just how complex such star systems can be. Mizar has been known for centuries to have a faint companion called Alcor, which can be seen without a telescope. Mizar and Alcor form an optical double —a pair of stars that appear close together in the sky but do not orbit each other. Through a telescope, as Riccioli discovered in 1650, Mizar can be seen to have another, closer companion that does orbit it; Mizar is thus a visual binary. The two components that make up this visual binary, known as Mizar A and Mizar B, are both spectroscopic binaries. So, Mizar is really a quadruple system of stars.
Strictly speaking, it is not correct to describe the motion of a binary star system by saying that one star orbits the other. Gravity is a mutual attraction. Each star exerts a gravitational force on the other, with the result that both stars orbit a point between them called the center of mass . Imagine that the two stars are seated at either end of a seesaw. The point at which the fulcrum would have to be located in order for the seesaw to balance is the center of mass, and it is always closer to the more massive star (Figure \(\PageIndex{2}\)).
Figure \(\PageIndex{3}\) shows two stars (A and B) moving around their center of mass, along with one line in the spectrum of each star that we observe from the system at different times. When one star is approaching us relative to the center of mass, the other star is receding from us. In the top left illustration, star A is moving toward us, so the line in its spectrum is Doppler-shifted toward the blue end of the spectrum. Star B is moving away from us, so its line shows a redshift. When we observe the composite spectrum of the two stars, the line appears double. When the two stars are both moving across our line of sight (neither away from nor toward us), they both have the same radial velocity (that of the pair’s center of mass); hence, the spectral lines of the two stars come together. This is shown in the two bottom illustrations in Figure \(\PageIndex{3}\).
A plot showing how the velocities of the stars change with time is called a radial velocity curve ; the curve for the binary system in Figure \(\PageIndex{3}\) is shown in Figure \(\PageIndex{4}\).
This animation lets you follow the orbits of a binary star system in various combinations of the masses of the two stars.
Masses from the Orbits of Binary Stars
We can estimate the masses of binary star systems using Newton’s reformulation of Kepler’s third law (discussed in Newton’s Universal Law of Gravitation in Chapter 2). Kepler found that the time a planet takes to go around the Sun is related by a specific mathematical formula to its distance from the Sun. In our binary star situation, if two objects are in mutual revolution, then the period (\(P\)) with which they go around each other is related to the semimajor axis (\(D\)) of the orbit of one with respect to the other, according to this equation
\[D^3= \left( M_1+M_2 \right) P^2 \nonumber\]
where \(D\) is in astronomical units, \(P\) is measured in years, and \(M_1 + M_2\) is the sum of the masses of the two stars in units of the Sun’s mass. This is a very useful formula for astronomers; it says that if we can observe the size of the orbit and the period of mutual revolution of the stars in a binary system, we can calculate the sum of their masses.
Most spectroscopic binaries have periods ranging from a few days to a few months, with separations of usually less than 1 AU between their member stars. Recall that an AU is the distance from Earth to the Sun, so this is a small separation and very hard to see at the distances of stars. This is why many of these systems are known to be double only through careful study of their spectra.
We can analyze a radial velocity curve (such as the one in Figure \(\PageIndex{4}\)) to determine the masses of the stars in a spectroscopic binary. This is complex in practice but not hard in principle. We measure the speeds of the stars from the Doppler effect. We then determine the period—how long the stars take to go through an orbital cycle—from the velocity curve. Knowing how fast the stars are moving and how long they take to go around tells us the circumference of the orbit and, hence, the separation of the stars in kilometers or astronomical units. From Kepler’s law, the period and the separation allow us to calculate the sum of the stars’ masses.
Of course, knowing the sum of the masses is not as useful as knowing the mass of each star separately. But the relative orbital speeds of the two stars can tell us how much of the total mass each star has. As we saw in our seesaw analogy, the more massive star is closer to the center of mass and therefore has a smaller orbit. Therefore, it moves more slowly to get around in the same time compared to the more distant, lower-mass star. If we sort out the speeds relative to each other, we can sort out the masses relative to each other. In practice, we also need to know how the binary system is oriented in the sky to our line of sight, but if we do, and the just-described steps are carried out carefully, the result is a calculation of the masses of each of the two stars in the system.
To summarize, a good measurement of the motion of two stars around a common center of mass, combined with the laws of gravity, allows us to determine the masses of stars in such systems. These mass measurements are absolutely crucial to developing a theory of how stars evolve. One of the best things about this method is that it is independent of the location of the binary system. It works as well for stars 100 light-years away from us as for those in our immediate neighborhood.
To take a specific example, Sirius is one of the few binary stars in Appendix J for which we have enough information to apply Kepler’s third law:
\[D^3= \left( M_1+M_2 \right) P^2 \nonumber\]
In this case, the two stars, the one we usually call Sirius and its very faint companion, are separated by about 20 AU and have an orbital period of about 50 years. If we place these values in the formula we would have
\[\begin{array}{l} (20)^3= \left( M_1+M_2 \right) (50)^2 \\ 8000= \left( M_1+M_2 \right) (2500) \end{array} \nonumber\]
This can be solved for the sum of the masses:
\[M_1+M_2= \frac{8000}{2500}=3.2 \nonumber\]
Therefore, the sum of masses of the two stars in the Sirius binary system is 3.2 times the Sun’s mass. In order to determine the individual mass of each star, we would need the velocities of the two stars and the orientation of the orbit relative to our line of sight.
The Range of Stellar Masses
How large can the mass of a star be? Stars more massive than the Sun are rare. None of the stars within 30 light-years of the Sun has a mass greater than four times that of the Sun. Searches at large distances from the Sun have led to the discovery of a few stars with masses up to about 100 times that of the Sun, and a handful of stars (a few out of several billion) may have masses as large as 250 solar masses. However, most stars have less mass than the Sun.
According to theoretical calculations, the smallest mass that a true star can have is about 1/12 that of the Sun. By a “true” star, astronomers mean one that becomes hot enough to fuse protons to form helium (as discussed in The Sun: A Nuclear Powerhouse). Objects with masses between roughly 1/100 and 1/12 that of the Sun may produce energy for a brief time by means of nuclear reactions involving deuterium, but they do not become hot enough to fuse protons. Such objects are intermediate in mass between stars and planets and have been given the name brown dwarfs (Figure \(\PageIndex{5}\)). Brown dwarfs are similar to Jupiter in radius but have masses from approximately 13 to 80 times larger than the mass of Jupiter. 2
These images, taken with the Hubble Space Telescope, show the region surrounding the Trapezium star cluster inside the star-forming region called the Orion Nebula. (a) No brown dwarfs are seen in the visible light image, both because they put out very little light in the visible and because they are hidden within the clouds of dust in this region. (b) This image was taken in infrared light, which can make its way to us through the dust. The faintest objects in this image are brown dwarfs with masses between 13 and 80 times the mass of Jupiter. (credit a: NASA, C.R. O’Dell and S.K. Wong (Rice University); credit b: NASA; K.L. Luhman (Harvard-Smithsonian Center for Astrophysics) and G. Schneider, E. Young, G. Rieke, A. Cotera, H. Chen, M. Rieke, R. Thompson (Steward Observatory))
Still-smaller objects with masses less than about 1/100 the mass of the Sun (or 10 Jupiter masses) are called planets. They may radiate energy produced by the radioactive elements that they contain, and they may also radiate heat generated by slowly compressing under their own weight (a process called gravitational contraction). However, their interiors will never reach temperatures high enough for any nuclear reactions, to take place. Jupiter, whose mass is about 1/1000 the mass of the Sun, is unquestionably a planet, for example. Until the 1990s, we could only detect planets in our own solar system, but now we have thousands of them elsewhere as well. (We will discuss these exciting observations in The Birth of Stars and the Discovery of Planets outside the Solar System.)
The Mass-Luminosity Relation
Now that we have measurements of the characteristics of many different types of stars, we can search for relationships among the characteristics. For example, we can ask whether the mass and luminosity of a star are related. It turns out that for most stars, they are: The more massive stars are generally also the more luminous. This relationship, known as the mass-luminosity relation , is shown graphically in Figure \(\PageIndex{6}\). Each point represents a star whose mass and luminosity are both known. The horizontal position on the graph shows the star’s mass, given in units of the Sun’s mass, and the vertical position shows its luminosity in units of the Sun’s luminosity.
We can also say this in mathematical terms.
\[L \sim M^{3.9} \nonumber\]
It’s a reasonably good approximation to say that luminosity (expressed in units of the Sun’s luminosity) varies as the fourth power of the mass (in units of the Sun’s mass). (The symbol ~ means the two quantities are proportional.) If two stars differ in mass by a factor of 2, then the more massive one will be 2 4 , or about 16 times brighter; if one star is 1/3 the mass of another, it will be approximately 81 times less luminous.
Example \(\PageIndex{1}\): calculating the mass from the luminosity of a star
The mass-luminosity formula can be rewritten so that a value of mass can be determined if the luminosity is known.
- Answer
-
First, we must get our units right by expressing both the mass and the luminosity of a star in units of the Sun’s mass and luminosity:
\[L/L_{\text{Sun}}= \left( M/M_{\text{Sun}} \right)^4 \nonumber\]
Now we can take the 4th root of both sides, which is equivalent to taking both sides to the 1/4 = 0.25 power. The formula in this case would be:
\[M/M_{\text{Sun}} = \left( L/L_{\text{Sun}} \right)^{0.25}= \left(L/L_{\text{Sun}} \right)^{0.25} \nonumber\]
Exercise \(\PageIndex{1}\)
In the previous section, we determined the sum of the masses of the two stars in the Sirius binary system (Sirius and its faint companion) using Kepler’s third law to be 3.2 solar masses. Using the mass-luminosity relationship, calculate the mass of each individual star.
- Answer
-
In Appendix J, Sirius is listed with a luminosity 23 times that of the Sun. This value can be inserted into the mass-luminosity relationship to get the mass of Sirius: \(M/M_{\text{Sun}}=23^{0.25}=2.2\)
The mass of the companion star to Sirius is then \(3.2 – 2.2 = 1.0\) solar mass.
Notice how good this mass-luminosity relationship is. Most stars (see Figure \(\PageIndex{6}\)) fall along a line running from the lower-left (low mass, low luminosity) corner of the diagram to the upper-right (high mass, high luminosity) corner. About 90% of all stars obey the mass-luminosity relation. Later, we will explore why such a relationship exists and what we can learn from the roughly 10% of stars that “disobey” it.
Key Concepts and Summary
The masses of stars can be determined by analysis of the orbit of binary stars—two stars that orbit a common center of mass. In visual binaries, the two stars can be seen separately in a telescope, whereas in a spectroscopic binary, only the spectrum reveals the presence of two stars. Stellar masses range from about 1/12 to more than 100 times the mass of the Sun (in rare cases, going to 250 times the Sun’s mass). Objects with masses between 1/12 and 1/100 that of the Sun are called brown dwarfs. Objects in which no nuclear reactions can take place are planets. The most massive stars are, in most cases, also the most luminous, and this correlation is known as the mass-luminosity relation.
Footnotes
1 Exactly where to put the dividing line between planets and brown dwarfs is a subject of some debate among astronomers as we write this book (as is, in fact, the exact definition of each of these objects). Even those who accept deuterium fusion (see The Birth of Stars and the Discovery of Planets outside the Solar System) as the crucial issue for brown dwarfs concede that, depending on the composition of the star and other factors, the lowest mass for such a dwarf could be anywhere from 11 to 16 Jupiter masses.
Glossary
- binary stars
- two stars that revolve about each other
- brown dwarf
- an object intermediate in size between a planet and a star; the approximate mass range is from about 1/100 of the mass of the Sun up to the lower mass limit for self-sustaining nuclear reactions, which is about 1/12 the mass of the Sun
- mass-luminosity relation
- the observed relation between the masses and luminosities of many (90% of all) stars
- spectroscopic binary
- a binary star in which the components are not resolved but whose binary nature is indicated by periodic variations in radial velocity, indicating orbital motion
- visual binary
- a binary star in which the two components are telescopically resolved
Contributors and Attributions
-
Andrew Fraknoi (Foothill College), David Morrison (NASA Ames Research Center), Sidney C. Wolff (National Optical Astronomy Observatory) with many contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at https://openstax.org/details/books/astronomy ). | 4,101 | common-pile/libretexts_filtered | https://phys.libretexts.org/Courses/Grossmont_College/ASTR_110%3A_Astronomy_(Fitzgerald)/10%3A_Nature_of_Stars/10.06%3A_Measuring_Stellar_Masses_Part_2 | libretexts | libretexts-0000.json.gz:39171 | https://phys.libretexts.org/Courses/Grossmont_College/ASTR_110%3A_Astronomy_(Fitzgerald)/10%3A_Nature_of_Stars/10.06%3A_Measuring_Stellar_Masses_Part_2 |
s1tGc3AOIWxqPYQl | Fundamentals of Communication | 2.2 Perceiving Others
Are you a good judge of character? How quickly can you “size someone up”? Interestingly, research shows that many people are surprisingly accurate at predicting how an interaction with someone will unfold based on initial impressions. Fascinating research has also been done on the ability of people to make a judgment about a person’s competence after as little as 100 milliseconds of exposure to politicians’ faces. Even more surprising is that people’s judgments of competence, after exposure to two candidates for senate elections, accurately predicted election outcomes (Ballew and Todorov). In short, after only minimal exposure to a candidate’s facial expressions, people made judgments about the person’s competence, and those candidates judged more competent were people who actually won elections! As you read this section, keep in mind that these principles apply to how you perceive others and to how others perceive you. Just as others make impressions on us, we make impressions on others. We have already learned how the perception process works in terms of selecting, organizing, and interpreting. In this section, we will focus on how we perceive others with specific attention to how we interpret our perceptions of others.
Attribution and Interpretation
I’m sure you have a family member, friend, or coworker with whom you have ideological or political differences. When conversations and inevitable disagreements occur, you may view this person as “pushing your buttons” if you are invested in the issue being debated, or you may view the person as “on their soapbox” if you aren’t invested. I don’t know why I even bother trying to talk to her!” Similar situations occur regularly, and there are some key psychological processes that play into how we perceive others’ behaviors. By examining these processes, attribution in particular, we can see how our communication with others is affected by the explanations we create for others’ behavior. In addition, we will learn some common errors that we make in the attribution process that regularly lead to conflict and misunderstanding.
In most interactions, we are constantly making attributions through which we invent explanations for what is happening. Why did my neighbor slam the door when she saw me walking down the hall? Why is my partner being extra nice to me today? Why did my officemate miss our project team meeting this morning? In general, we seek to attribute the cause of others’ behaviors to internal or external factors. Internal attributions connect the cause of behaviors to personal aspects such as personality traits. External attributions connect the cause of behaviors to situational factors. Attributions are important to consider because our reactions to others’ behaviors are strongly influenced by the explanations we reach.
Imagine that Gloria and Jerry are dating. One day, Jerry gets frustrated and raises his voice to Gloria. She may find that behavior more offensive and even consider breaking up with him if she attributes the cause of the blowup to his personality, since personality traits are usually fairly stable and difficult to control or change. Conversely, Gloria may be more forgiving if she attributes the cause of his behavior to situational factors beyond Jerry’s control, since external factors are usually temporary. If she makes an internal attribution, Gloria may think, “Wow, this person is really a loose cannon. Who knows when he will lose it again?” If she makes an external attribution, she may think, “Jerry has been under a lot of pressure to meet deadlines at work and hasn’t been getting much sleep. Once this project is over, I’m sure he’ll be more relaxed.” This process of attribution is ongoing, and, as with many aspects of perception, we are sometimes aware of the attributions we make, and sometimes they are automatic and/or unconscious.
Attribution has received much scholarly attention because it is in this part of the perception process that some of the most common perceptual errors or biases occur. One of the most common perceptual errors is the fundamental attribution error, which refers to our tendency to explain others’ behaviors using internal rather than external attributions (Sillars, 183). For example, when I worked at an urban college in Denver, Colorado, I often had students come into class irritated, saying, “I got a parking ticket! I can’t believe those people. If you Google some clips from the reality television show Parking Wars, you will see the ire that people often direct at parking enforcement officers. In this case, illegally parked students attribute the cause of their situation to the malevolence of the parking officer, essentially saying they got a ticket because the officer was a mean/bad person, which is an internal attribution. Students were much less likely to acknowledge that the officer was just doing his or her job (an external attribution) and that the ticket was a result of the student’s decision to park illegally.
Perceptual errors can also be biased, and in the case of the self-serving bias, the error works out in our favor. Just as we tend to attribute others’ behaviors to internal rather than external causes, we do the same for ourselves, especially when our behaviors have led to something successful or positive. When our behaviors lead to failure or something negative, we tend to attribute the cause to external factors. Thus, the self-serving bias is a perceptual error through which we attribute the cause of our successes to internal personal factors while attributing our failures to external factors beyond our control. When we look at the fundamental error and the self-serving bias together, we can see that we are likely to judge ourselves more favorably than another person, or at least less personally.
The professor-student relationship offers a good case example of how these concepts can play out. I have often heard students who earned an unsatisfactory grade on an assignment attribute that grade to the strictness, unfairness, or incompetence of their professor. I have also heard professors attribute a poor grade to the student’s laziness, attitude, or intelligence. In both cases, the behavior is explained using an internal attribution and is an example of the fundamental attribution error. Students may further attribute their poor grades to their busy schedules or other external, situational factors rather than their lack of motivation, interest, or preparation (internal attributions). On the other hand, when students get a good grade on a paper, they will likely attribute that cause to their intelligence or hard work rather than an easy assignment or an “easy grading” professor. Both of these examples illustrate the self-serving bias. These psychological processes have implications for our communication because when we attribute causality to another person’s personality, we tend to have a stronger emotional reaction and tend to assume that this personality characteristic is stable, which may lead us to avoid communication with the person or to react negatively. Now that you’re aware of these common errors, you can monitor them more and engage in perception checking, which we will learn more about later, to verify your attributions.
Physical and Environmental Influences on Perception
We make first impressions based on a variety of factors, including physical and environmental characteristics. In terms of physical characteristics, style of dress and grooming are important, especially in professional contexts. We have a general schema regarding how to dress and groom for various situations ranging from formal to business casual to casual to lounging around the house.
You would likely be able to offer some descriptors of how a person would look and act from the following categories: a goth person, a prep, a jock, a fashionista, and a hipster. The schemata associated with these various cliques or styles are formed through personal experience and through exposure to media representations of these groups. Different professions also have schemata for appearance and dress. Imagine a doctor, mechanic, congressperson, exotic dancer, or mail carrier. Each group has clothing and personal styles that create and fit into general patterns. Of course, the mental picture we have of any of the examples above is not going to be representative of the whole group, meaning that stereotypical thinking often exists within our schema. We will learn more about the negative effects of stereotypical thinking later in the chapter, but it’s important to understand how persuasive various physical perceptual influences can be.
Think about the harm that has been done when people pose as police or doctors to commit crimes or other acts of malice. Seeing someone in a white lab coat automatically leads us to see that person as an authority figure, and we fall into a scripted pattern of deferring to the “doctor” and not asking too many questions. The Milgram experiments offer a startling example of how powerful these influences are. In the experiments, participants followed instructions from a man in a white lab coat (who was actually an actor), who prompted them to deliver electric shocks to a person in another room every time the other person answered a memory question incorrectly. The experiment was actually about how people defer to authority figures instead of acting independently. Although no one was actually being shocked in the other room, many participants continued to “shock,” at very high levels of voltage, the other person even after that person was supposedly being shocked complained of chest pains and became unresponsive (Encina).
Just as clothing and personal style help us form impressions of others, so do physical body features. The degree to which we perceive people to be attractive influences our attitudes about and communication with them. Facial attractiveness and body weight tend to be common features used in the perception of physical attractiveness. In general, people find symmetrical faces and nonoverweight bodies attractive. People perceived as attractive are generally evaluated more positively and seen as kinder and more competent than people evaluated as less attractive. Additionally, people rated as attractive receive more eye contact, more smiles, and closer proximity to others (people stand closer to them).
Although some physical and environmental features are easier to change than others, it is useful to become aware of how these factors, which aren’t necessarily related to personality or verbal and nonverbal communication, shape our perceptions. These early impressions also affect how we interpret and perceive later encounters, which can be further explained through the halo and horn effects.
The Halo and Horn Effects
We have a tendency to adapt information that conflicts with our earlier impressions in order to make it fit within the frame we have established. This is known as selective distortion, and it manifests in the halo and horn effects. The angelic halo and devilish horn are useful metaphors for the lasting effects of positive and negative impressions. The halo effect occurs when initial positive perceptions lead us to view later interactions as positive. The horn effect occurs when initial negative perceptions lead us to view later interactions as negative (Hargie, 281).
Since impressions are especially important when a person is navigating the job market, let’s imagine how the horn and halo effects could play out for a recent college graduate looking to land her first real job. Nell has recently graduated with her degree in communication studies and is looking to start her career as a corporate trainer. If one of Nell’s professors has a relationship with an executive at an area business, his positive verbal recommendation will likely result in a halo effect for Nell. Since the executive thinks highly of his friend the professor and the professor thinks highly of Nell, then the executive will start his interaction with Nell with a positive impression and interpret her behaviors more positively than he would otherwise. The halo effect initiated by the professor’s recommendation may even lead the executive to dismiss or overlook some negative behaviors. Let’s say Nell doesn’t have a third party to help make a connection and arrives late for her interview. That negative impression may create a horn effect that carries through the interview. Even if Nell presents as competent and friendly, the negative first impression could lead the executive to minimize or ignore those positive characteristics, and the company may not hire her.
Summary of Perceiving Others
We use attributions to interpret perceptual information, specifically, people’s behavior. Internal attributions connect behavior to internal characteristics such as personality traits. External attributions connect behavior to external characteristics such as situational factors. Two common perceptual errors that occur in the process of attribution are the fundamental attribution error and the self-serving bias. The fundamental attribution error refers to our tendency to overattribute other people’s behaviors to internal rather than external causes. The self-serving bias refers to our tendency to overattribute our successes to internal factors and overattribute our failures to external factors. The halo effect describes a perceptual effect that occurs when initial positive impressions lead us to view later interactions as positive. The horn effect describes a perceptual effect that occurs when initial negative impressions lead us to view later interactions as negative.
The process of selecting, organizing, and interpreting information.
Focus attention on certain incoming sensory information.
Sort and categorize information that we perceive based on innate and learned cognitive patterns called schemata.
The process of assigning meaning to our experiences using schemata.
An explanation for what is happening.
Connect the cause of behaviors to personal aspects such as personality traits.
Connect the cause of behaviors to situational factors.
Tendency to explain others’ behaviors using internal rather than external attributions.
Attributing the cause of our successes to internal personal factors while attributing our failures to external factors beyond our control.
Innate and learned cognitive patterns such as prototypes, personal construct, stereotypes, and scripts.
Initial positive perceptions lead us to view later interactions as positive.
Initial negative perceptions lead us to view later interactions as negative. | 2,966 | common-pile/pressbooks_filtered | https://louis.pressbooks.pub/fundamentalsofcomm/chapter/2-2-perceiving-others/ | pressbooks | pressbooks-0000.json.gz:63822 | https://louis.pressbooks.pub/fundamentalsofcomm/chapter/2-2-perceiving-others/ |
5t2Q4nLMjmPiuBAv | 5.3: Treating Mental Illness | 5.3: Treating Mental Illness
It is important to know that while mental illness can have long-term effects on a person’s physical, psychological, and social functioning, many people can recover and lead normal lives. There are many types of treatment available. The most common types of treatment include medication and psychotherapy (counseling).
It is extremely important for a person with a mental illness to take their medication as prescribed. Home Health Aides/Personal Care Aides may come to observe patients who do not take their medication as prescribed. They should inform their supervisor and document their findings.
Sometimes a person who is suffering from a severe form of mental illness and who is unable to help themselves may need to be hospitalized for periods of time. Most people who suffer from a mental illness receive outpatient treatment , which is treatment outside of a hospital. Patients meet with a psychiatrist (a physician who specializes in treating mental health disorders) to discuss their thoughts and feelings and to obtain prescriptions for medications. Patients may also meet with a mental health therapist or social worker (specialists who focus on working with people with mental health issues by providing counseling) to talk about their thoughts and feelings and to learn better ways to cope with their stressors.
Some people go to individual therapy (therapy focused on one person) and others may go to group therapy (therapy where many people with similar problems meet with a therapist) to talk about and solve their problems. A common form of treatment is c . This treatment focuses on how a person’s thoughts, feelings, and behaviors are related. Patients are taught to recognize negative self-talk (what we tell ourselves in our head) and to turn these thoughts into more positive ones. More positive thoughts will lead to improved mood and behavior.
1. People who suffer from mental illness can recover with proper treatment.True or False. _______
2. By recognizing how negative thoughts can affect how a person behaves and feels, people can learn to turn negative thoughts into positive ones. True or False. _______
- Answer
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Add texts here. Do not delete this text first.
Mental Health, Mental Illness, and the Home Care Worker
Guidelines for Observing Behavior:
- Describe the unusual behavior. When does it occur? How often does it occur? How long does it last? Does it seem to occur during certain situations?
- Does the behavior indicate a change in the patient’s personality?
- Is the behavior or thought extreme (bizarre and seem abnormal)? Is the behavior or thought appropriate to the situation, or does it seem out of the ordinary and abnormal?
- Is the behavior harmful to the patient, to their loves ones, or to the Home Health Aide/Personal Care Aide?
It is important to remember not to draw conclusions about the behaviors observed. The job of a HHA/PCA is not to diagnose or interpret behaviors or thoughts the patient expresses. Their job is to observe, record, and report what they see and hear.
Role of the HHA/PHA with Mentally Ill Patients and their Families
Home Health Aides/Personal Care Aides play an important role in helping a patient with mental illness and their family function normally and safely. They assist patients with medications as allowed by their state, agency, and the Care Plan. They observe, record, and report any changes in mood, behavior, or side effects from medications. They should take note of what is happening in the home. Is the home unkempt? Is the patient’s personal appearance unkempt? Are children neglected?
People who suffer from a mental illness may not be able to provide for their personal care needs or to maintain a clean and safe home. It is the responsibility of the HHA/PCA to assist them to complete their activities of daily living (ADLs). This includes assisting with bathing, dressing, toileting, and self-care. This also may include assisting with light housekeeping and helping to plan, shop, and prepare meals. A HHA/PCA may also be asked to observe whether a patient is compliant (follows) their treatment plan. Do they take their medications as ordered? Do they attend psychiatric appointments?
Home Health Aides/Personal Care Aides play an important role in providing emotional support and assisting a person with mental health issues to use positive coping strategies. They also work to support the family members during the process of recovery. They must use their communication skills to listen to concerns and provide emotional support and role model healthy coping skills and effective communication skills. Be aware of including the patient in the treatment plan. Respect their confidentiality. Just because they have a mental health issue does not mean that they lose the right for confidential and respectful treatment. Be patient, compassionate, kind, and respectful of the patient and family. Most importantly, always offer hope that people with mental illness may recover.
Maintain Safety
Home Health Aides/Personal Care Aides should discuss the Care Plan with their supervisor and treatment team on a regular basis to ensure that they are always following the directions outlined in the Care Plan. This is to ensure the safety of them and their patient, and to ensure that their patient receives the proper care. In some instances, patients may require very close supervision and constant attention. These patients may be at risk to harm themselves or others. Never leave these patients alone unsupervised.
Home Health Aides/Personal Care Aides should provide observations as asked and report any concerns immediately. Maintain careful documentation and accurately record observations. Remember not to include judgments within documentation. Do not include interpretations of behaviors such as, “Mr. Alman is talking to himself today. I think he needs a higher dose of medications.” Interpreting behaviors and making diagnoses is not the responsibility of the HHA/PCA. Maintain objectivity at all times. Only report what you see, hear, smell, and can touch.
It is important to always maintain safety within the home. Never leave a patient unattended if it is required they receive constant supervision or if they have made statements to hurt or kill themselves. Help to keep the home environment clean and free of debris and pests. Provide personal care to the patient as directed in the Care Plan. People with mental illness may be unable to provide personal care for themselves and may rely on the HHA/PCA to help remind or assist them with these activities.
Observe and report noncompliance with medications and psychiatric treatment. Noncompliance means that a patient is not following the treatment plan or medical recommendations as directed. There may be many reasons for this. Some medications that people take to help them recover from mental illness may make them feel drowsy, not like themselves, have no energy, or even diminish their sexual drive. Patients may not like these side effects. Patients may also be non-compliant with treatment because they have difficulty remembering to take medications or to attend appointments. If Home Health Aides/Personal Care Aides notice noncompliance in their patient, they should try to ask them what may be happening to make them not want to take their medications or miss their treatment appointments. Whatever the reason may be record and report noncompliance and any reasons discovered. Without following the treatment plan, patients will be unable to recover from their mental illness and live a safe and functional life.
In the case of extreme, dangerous, or unsafe situations or behaviors, immediately call 911 or the emergency phone number in your area. Home Health Aides/Personal Care Aides should use their communication skills and appropriate telephone skills to accurately and calmly report the situation. Provide only the facts to emergency services and try to remain calm. Then, when it is safe, call a supervisor to report the situation.Never stay in a situation that is unsafe. | 1,678 | common-pile/libretexts_filtered | https://med.libretexts.org/Bookshelves/Allied_Health/Foundations_for_Assisting_in_Home_Care_(McLain_O'Hara-Leslie_and_Wade)/05%3A_Working_with_People_who_are_Mentally_Ill/5.03%3A_Treating_Mental_Illness | libretexts | libretexts-0000.json.gz:12001 | https://med.libretexts.org/Bookshelves/Allied_Health/Foundations_for_Assisting_in_Home_Care_(McLain_O'Hara-Leslie_and_Wade)/05%3A_Working_with_People_who_are_Mentally_Ill/5.03%3A_Treating_Mental_Illness |
TeVYpRIldQ4z2hqi | A method making possible the utilization of an Illinois joint clay, by A.V. Bleininger and F.E. Layman. An Attempt to determine the amount of heat utilized from a down-draft kiln by the waste heat drying system, by A.V. Belininger. | The person charging this material is responsible for its return to the library from which it was withdrawn on or before the Latest Date stamped below.
Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University.
In a test made some time ago the heat distribution of a down-draft kiln employed for burning hard building brick was calculated, based upon careful measurements of the kiln and exit temperatures, the composition of the waste uases, the fuel and the asbes, together with the weight of the coal and of the ware. The result was summarized as follows ;
At the close of the burn a 30-inch goose-neck was inserted into the door of the kiln which connected with an underground flue leading to the dryer. The air was thus drawn from the kiln by means of the large fan located at the dryer. A draft gauge was then connected with the ^■oose-neck for determining the "head" caused by the pull of the fan. This was found to be quite uniform and equal to 14 divisions of the Richardson-Lovejoy petroleum gauge which corresponds to about 14 inch of water by actual measurement. A thermo couple was likewise inserted into the goose-neck which was replaced later by thermometers.
was carefully measured for 108 hours.
In attempting- to calculate the amount of heat exhausted from the kiln by means of the fan we must know first the velocity of the air through the pipe. This it was only possible to approximate, since the draft gauge was not calibrated against an anemometer. The final value of the velocity accepted is lower than the actual velocity, since no attempt was made to use the Pitot tube correction factor, which is greater than unity. The theoretical velocity calculated from the head shown by the gauge, giving a lower value was hence used, neglecting the decrease in the viscosity of the hot air and other factors due to cooling between the kiln and the fan. This, it is believed, did not introduce any significant error, since evidently the velocity was fairly uniform throughout the test. The velocity is thus calculated from the formula.
second.
The time was divided into nine periods of 12 hours each and the mean exit temperature calculated for every period. These were found to be as follows :
With a pipe diameter of 30 inches and using the velocity above calculated we have a discharge of 4.18 en. in. per second or of 180,576 en. in. during 12 hours. Owing to the fact that the test was carried on during the dryest
and hottest part of the summer, with an average temperature of about 20°, the humidity approximated at 50%. This figure is purely a guess, since the hygrometer was found to have been broken during transit. However, the introduction of the atmospheric moisture factor is not an important one, numerically. Assuming a vapor tension of 8.7 mm, the volume of steam introduced for the volume of air given above would be 21194 eu. m. The barometric pressure was taken to be 750 mm.
There remains now to calculate the weights of air and steam taken through the pipe for each period as well as the heat removed. This is illustrated for the first period as follows :•
Total 75,364.980 kg. Cals.
The coal used during the burn had a calorific value of 6200. Hence the weight of coal equivalent to the amount of heat drawn from the kiln would be
20,741 pounds. During the entire burn 95,045 pounds of coal were used. The heat exhausted from the kiln during cooling then equals 28.1% of the total heat introduced, so that the heat distribution could be rearranged as follows :
The recovered heat thus amounts to the equivalent of practically 400 pounds of coal per thousand bricks, or speaking more correctly, about 130 pounds of coal per ton of burnt clay, which is more than the heat theoretically required to burn the bricks. It is evident that not all of this heat is used in drying bricks, some of it is lost on the way to the dryer and in the latter itself. That a considerable amount of the heat is derived from the hot kiln walls is apparent from the comparison of the figures in the final distribution. Owing to the fact that this test was carried on in summer, the results show the most favorable conditions under which this particular kiln operates. In winter the heat actually available for drying would be considerably less, owing to the increased loss by radiation during cooling.
A. V. Bleiningek and F. E. Layman.
A large part of Northern and Central Illinois is covered by the so-called joint clays which arc of glacial origin and vary in depth from one to five feet. These (days are weathered to different depths and in this condition they form the basis of a considerable brick industry. They are red-burning surface clays, extremely fine in "rain, but as is characteristic of glacial deposits, admixed with mineral detritus of all kinds. In a number of localities, however, they are quite uniform in composition for considerable areas ami free from excessive amounts of rock deiiris, gravel, etc.
In the weathered condition they usually work up quit" well into bricks and tiles though they are sometimes liable to check in burning. Some distance below the surface, however, they are apt to show a peculiar behavior in drying, giving rise to characteristic splitting and cracking'.
When made into bricks they split through vertically into more or less regular cubes, the same thing being observed when a bank is stripped and the surface is drying out. The loss arising from this peculiarity in attempting to make clay products out of this material is quite considerable, since the checking occurs in the drying as well as in the burning, the latter being due probably to incipient cracks.
A typical deposit of this character is found on the land of Mr. J. W. Stipes, close to the city of Urbana, 111. This clay is extremely line grained, red burning, very sticky and plastic but not high in bonding power. Within
a foot of the surface it has been (■hanged by weathering so that it does not show the peculiarity mentioned above to a striking degree but at a somewhat greater depth its true joint structure appears. There arc no differences in color noticeable between the weathered and the unweathered portion, both are of about the same yellow. The clay is comparatively free from mineral debris and stands up remarkably well in the kiln. Though at present used for the manufacture of soft-mud bricks and burnt in up-draft kilns, this process does not do the clay justice and does not bring eut its best colors, as a down-draft kiln would do. It vitrifies between cones 3 and 1. When burnt at a lower temperature it produces a fine red color.
It has been realized from experience that both weathering and thorough air drying help considerably in overcoming the difficulties encountered in the use of this clay. Hence, by allowing it to freeze through the winter it would become quite workable in the spring. The difficulty is, however, in being sure that all of the clay has been sufficiently weathered, and though the drying loss may be reduced, some loss in burning may still be found to occur. the same thing applying to the air drying.
Considering the benefit derived from air drying, it was proposed to carry this process further and to dry the clay at higher temperatures. For this purpose a sample was taken from that part of the bank, used by the Sheldon Brick Company, that had given the most trouble.
In the preliminary work, small samples of this clay were dried in a laboratory air bath at 100, 200 and 300°C. These were then pulverized, passed through an eight mesh screen, tempered, wedged and pressed into bars, 10" x |" x i/o" in a brass mould. A portion of the undried clay was also wedged and pressed in the same mould. After drying in the air at ordinary temperature the linear shrinkages were determined. It was found that the bar made from the undried clay warped very badly as well as the bar made from the clay dried at 100°, but that the bars moulded from the clay dried at 200° and 300° showed very little warping.
In tempering the dried clay it was observed that the sample dried at 100 still possessed the sticky nature of the undried clay, while the charge dried at 200° had lost to a very large extent this characteristic property. At the same time a certain granular appearance was noticed as well as a slight change in color from yellow to reddish. The sample dried at 300 worked practically the same as I he one heated to 200°. Hence, it was obvious that whatever changes had taken place in the structure of the clay occurred at aboul 200 <\ and this was the temperature chosen in tin1 work that followed.
In order to bring out the changes caused by this drying treatment, still further experiments were made. A sample of the undried clay was taken and divided into two parts. One-half was dried at 200° in a laboratory oven, the other half was left as it was. Both of these batches were placed in porcelain jar mills of one gallon size, together
with sufficient distilled water to make a fairly thick slip, and ground for one hour. The grinding action of these small mills is very slight so that the fineness of grain was affected hut little. Each of the two slips was passed through an 80 mesh sieve.
The viscosity of each of the slips was then determined by means of n Coulomb viscosimeter which had been constructed in the Department of Ceramics, University of Illinois, for the purpose of studying clay slips, as described in Vol. X, Trans. Am. Ceramic Society.
The amount of (day held in suspension in the slips was determined by evaporating the slips to dryness and weighing in small metal pans. In order to obtain the viscosities <>f lower concentrations, the slips were diluted with water, thoroughly stirred up and tested as before.
In the accompanying curves we observe clearly what great changes have been brought about by the drying treatment. It is evident that this change involves the structure of the colloidal portion of the clay, since naturally neither the size of grain was altered nor anything added to or subtracted from the (day in drying. Just how long a time would be required to bring back the clay to its original state of viscosity, if this is possible at all, would be an interesting question.
We observe from the curves that for instance in the case of the fresh (day a viscosity of 1.18 is reached with 20% of clay, while for the same viscosity 35% of the dried (day is required. The latter therefore shows a marked decrease in the viscosity characteristic of plastic clays.
In order to bring out the differences between the undried and the dried clay still further, another series of tests was made by taking these (days alone and in several proportions and making them up into round discs, 3*4 inin diameter and 7/8 in. thick. For this purpose the fresh clay was thoroughly wedged, while the dry clay was pulverized and passed through a 10 mesh screen, made up with water and tempered. The discs were made by batting the clay into a slab between two guides and passing a roller over the latter so as to obtain uniform thickness. Ten trials of each serif's were placed in a Seger volnminometer and the volume determined by displacement in kerosene after having been immersed in petroleum for 24 hours. The same process was repeated after the discs were dry. The average of ten determinations was taken as the drying shrinkage. The dry test pieces were all placed in a Caulkins mnftie kiln, tired with oil and burnt to cone 4, this temperature having previously been determined as the best maturing point of the clay. Each of the ten trial pieces of the several series which had been measured for drying shrinkage, was, after burning, again placed in the volulninometer and the volume determined. The balance of the trials were placed in water with one face exposed and allowed to stand for 48 hours, this period of time having been established as the point beyond which practically no farther absorption took place. They were then divided into classes according to the absorption found.
At the same time discs were made in similar manner from (Jalesbnrg shah- which, however, were tired at cone 2, the best temperature for this material. The results of this work are collected in the following tables, the shrinkage being expressed by per cent in volume. The percentages of loss are based upon 200 discs made from the undried Urbana clay, 200 of the dried Urbana clay, and 125 discs of A, 15, and C.
From these results it is apparent that the pre-heating of the day has greatly decreased the drying shrinkage, the difference being 11.9 per cent in volume or nearly 4 per cent in linear shrinkage, assuming for practical purposes that the linear shrinkage is one-third of that in volume. A curious fact is also the decreased burning shrinkage, so that the total shrinkage is decreased from 62.3% by volume to 49.9$ , resulting in a difference of 12.4%. Or, expressed in linear dimensions, the decrease in total shrinkage is from 20.7% to 16.6%. The loss in drying which took place in the open laboratory at ordinary room temperature has been decreased from 32.0 to 0.5%, a gain of 31.5%. The gain in burning loss was 11%' and in the total loss 42.5%.
As to the mixtures of preheated and undried clay, we observe that the shrinkage and losses decrease roughly with the increase of preheated clay and thus these results verify the observations on the preheated clay itself.
Since there is a possibility from the practical standpoint of the drying and burning losses that the same results would be obtained by the addition of sand to the clay, a short series was carried through in which 5, 10 and 15% of sand passing the 8-mesh sieve were added to the undried Urbana clay. Of each sand mixture 125 discs were made. The results of this work are collected in the following table in which the data for the undried and the preheated clay are repeated for the sake of comparison :
From these results we observe that the drying shrinkage has been decreased somewhat ami the drying loss a good deal, roughly by about 25%. The burning shrinkage also has been reduced, but unfortunately the burning loss, though showing an improvement in the .V, sand mixture, increased very rapidly with more sand. As compared with the total loss of the preheated clay, the gain has been but small and at least as far as the sand used was concerned this remedy offers but little hope for practical improvement since the losses arc still too great. Tin1 advantage of preheating this joint clay is seen from the small loss in drying and burning. An explanation of the ineffectiveness of the sand mixture perhaps is due to the fact that the clay itself is not changed in its physical properties and we have here simply a case of dilution. With larger amounts of sand we also have in burning certain volume changes which appear to be opposed to each other, so that strains are produced which result disastrously.
In order to show whether the Urbana joint clay after having been burnt apparently to a sound body really was free from incipient checking, it was determined to make rattler tests. For this purpose the burnt discs, tree from flaws, were first graded according to their water absorption and compared with discs made from Galesburg shale which had burnt to the best degree of maturity.
The rattler test was made in a Scheibell mill, consisting of a chilled iron receptacle, elliptical in cross section, with a long axis 23 in. in length and a short axis of 7y2 in., revolving 31 revolutions per minute. The rattler was first standardized with a mixture of iron jackstones in the shape of I1 4 in. cubes weighing on an average 0.9 pound and Iceland pebbles with an average length of 3% in- and a width of 2% in. The average weight was 0.7 pound. In the standardization the Galesburg discs were used, five of them in a charge which weighed about 2.2 pounds. The combination giving the most constant results was used for the comparative tests of the joint clay discs with the Galesburg test pieces. In each case the results were checked. Finally, two charges were used, 2-C, containing 75 pounds of pebbles and 50 pounds of jackstones and 2-D,
consisting of 100 pounds of pebbles and 50 pounds of jackstones. In using charge 2-C the mill was about % full and with 2-1) it was y~ full. The time of running was one hour. It was found that 2-< 1 was a more severe charge than 2-D on account of the element of impact introduced by the mill being less full.
These results show plainly that preheating has improved the resistance of the joint clay to abrasion decidedly, not, of course, due to any change affecting the mineral and chemical structure of the (day itself, but to the elimination of drying defects, incipient cracks and strains caused in drying. If it were possible to dry tin1 fresh (day without injury it would possess the same resistance to abrasion exhibited by the preheated material. The Urbana clay is evidently more brittle than tin1 Galesburg shale, but it is harder, due to the fineness of grain of the joint clay. One might venture to say, judging from the above comparison, that the latter could probably be used as a paving material for streets which are not subject to heavy travel, provided, however, that the clay would correspond uniformly to the sample tested in this work, which is somewhat questionable in the case of glacial deposits.
The addition of sand, according to the above results, contributes nothing to the resistance to abrasion, though it shows an improvement over the undried (day by lessening the checking in drying.
CONCLUSIONS.
From the results of this work it is evident that the faults of the joint (day have been overcome by this preliminary drying treatment at 200°C. The sticky nature of the clay has been destroyed, tin1 drying shrinkage reduced greatly and the burning shrinkage partly, while the losses in drying have been practically eliminated and The burning loss lowered most decidedly. If, therefore, this preheating can be carried on economically in properly constructed dryers, either tired directly or making use of the waste heal of kilns, the treatment thus suggested ought to find more extensive practical application.
At the same time there must be remembered that the dry clay can be disintegrated and screened more cheaply than the clay coming wet from the bank, thus enabling the manufacturer to remove the impurities, such as gravel, lime, pebbles and other mineral detritus, which are especially liable to be present in the glacial clays, more cheaply and thoroughly, besides making the operator independent of weather conditions. Also it is thus possible to produce wares of a higher grade from low grade material and in districts where other clays are lacking. Tt is self-evident that the increased cost of production caused by this treatment may be prohibitory in localities where it is possible to find (days which do not require this kind of preparation. The matter of the preliminary drying of clay is not new, but the changes brought about by it have not been clearly recognized and its importance in certain cases not considered. It ought to lie especially applicable for higher grades of ware such as roofing tiles, hollow ware, terra cotta, etc.
In regard to the cost of drying clays by the rotary dryer, which is the most efficient apparatus for this purpose, some data have been obtained from two firms, A and P..
Firm A recommends a rotary dryer, heated by direct Siring, <><> in. in diameter and If! ft. long. This aparatus is encased in brick. The clay is fed automatically and at a constant rate, this being very important. About 35,000 common and from 5,000 to 6,000 fire brick are required in the construction. The total weight of the dryer is about 40 tons. The cost of the dryer, complete, is $3000, to which the freight is to be added. This machine will dry 15 tons of clay per hour. It will require 8 — 12 horsepower to operate and for a material containing 15rr <>f moisture the fuel consumption would be about 500 pounds of coal per hour, at the rate of 15 tons of clay for the same length of time. Including labor and depreciation the cost of drying is estimated at 10 cents per ton.
The firm B estimates the cost of the dryer to be $3,500 and cost of erection at $600. The power required is 20 horse-power and the fuel consumption 60 pounds of good ( oal per ton of bank clay. The cost of drying is estimated to be 12 cents per ton of bank (day.
In this connection we must remember also that the size of the brick moulds, etc., must be reduced in order to correspond to the decreased shrinkage of the preheated clay, though this do;>s not mean that a saving is effected.
Further work is necessary to determine to what extent this method may be applied to materials other than the joint clay discussed in these tests.
Practically all the laboratory work of this investigation was done by the junior writer, Mr. F. E. Layman, the senior writer having planned the experiments and assisted in writing up the results. The means for carrying on the tests were furnished by the Ceramic Department of tin1 University of Illinois, through Prof. C. W. Rolfe, the director.
| 4,840 | common-pile/pre_1929_books_filtered | methodmakingposs10blei | public_library | public_library_1929_dolma-0011.json.gz:3609 | https://archive.org/download/methodmakingposs10blei/methodmakingposs10blei_djvu.txt |
Mi0Q5SXYIquSSZxm | Entrepreneurship Law: Company Creation | Unit 18 Preview and Introduction
Preview
This unit will cover the following topics:
- Applicable Employment Laws
- At-will employment – Handbooks as implied contracts
- Required Provisions
- NLRA Section 7
- Industry Specific Provisions
- Employee Benefits
- Drafting Tips
Introduction
Every company that employs people needs to have an employee handbook to provide a list of benefits, policies, expectations, procedures, legal obligations, and guidelines. Employee handbooks are unique to every employer and should provide a detailed overview of the foregoing in a way that is specific to the business.
Handbooks serve many functions. One, it is a good way to introduce employees to the company culture, mission, and values. When employees review a handbook that sets forth the company culture, mission, and values, they feel more like they are part of a team – a sense of pride and belonging – which can lead to happier, more productive employees. A handbook is instrumental for communicating what is expected of employees. The handbook will outline procedures for requesting time off, procedures for reporting misconduct, hours of work, etc. It will also provide the benefits that the company offers.
Additionally, the handbook will outline legal notices and what the employee can expect from management. For instance, the handbook will outline policies/notice when one has jury duty.
Of interest to lawyers, is that the handbook can help defend against employee claims. The handbook can serve as additional evidence in a lawsuit with an employee or former employee. It can also minimize the risk of legal claims altogether by encouraging resolution of issues through internal complaint procedures.
This unit cannot and will not provide an exhaustive list of provisions to include in an employee handbook. Your client will need you to make those judgment calls based on the company’s needs. | 388 | common-pile/pressbooks_filtered | https://psu.pb.unizin.org/expsk909/chapter/unit-18-preview-and-introduction/ | pressbooks | pressbooks-0000.json.gz:34886 | https://psu.pb.unizin.org/expsk909/chapter/unit-18-preview-and-introduction/ |
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